JP2018193551A - Resin molded body, method for producing the same, and resin composition - Google Patents

Abstract

To provide a resin molded body having a property of absorbing or reflecting a specific wavelength region, high water resistance and moisture resistance, high strength, good dimensional stability, and antibacterial property, and showing peculiar optical characteristics depending on a moisture percentage, a production method of the resin molded body, and a resin composition.SOLUTION: The resin molded body comprises at least a synthetic resin having at least either an aqueous dispersion component or an aqueous emulsion component, and a composite. The composite is a composite of planar metal fine particles and a fine cellulose, in which the planar metal fine particles and at least one type of finely prepared cellulose are combined to form a composite in such a manner that each fine cellulose is at least partially or entirely taken in the planar metal fine particle, and the balance, if any, is exposed on a surface of the planar metal fine particles.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a resin molded body containing a plate-like metal / micronized cellulose composite (composite), a method for producing the same, and a resin composition.

  In recent years, in order to solve the problem of fossil resource depletion, functional materials using natural polymers, which are environmentally friendly materials that can be used continuously, have been actively developed. For example, plant materials such as cellulose are known as environmentally friendly natural polymer materials having biodegradability. Cellulose, the main component of plants and wood, is a natural polymer material that is accumulated in large quantities on the earth. In the wood, dozens or more cellulose molecules are bundled in wood to form fine fibers (microfibrils) having a high crystallinity and a fiber diameter on the order of nanometers. Furthermore, a large number of fine fibers are hydrogen-bonded to each other to form cellulose fibers, which are plant supports.

There is known a method of using this cellulose fiber by making it finer (nanofiber) until the fiber diameter becomes nanometer order. For example, a method is known in which an N-oxyl compound is used as an oxidation catalyst to oxidize part of a hydroxyl group of cellulose to at least one functional group selected from the group consisting of a carboxy group and an aldehyde group. According to this method, refined cellulose (hereinafter sometimes referred to as “CSNF”) having a cellulose I-type crystal structure having a maximum fiber diameter of 1000 nm or less and a number average fiber diameter of 2 nm to 150 nm is obtained. (For example, refer to Patent Document 1).
As an application example of micronized cellulose, for example, a packaging material having a gas barrier property such as oxygen, comprising a base material and a layer formed thereon and containing at least micronized cellulose, an inorganic layered compound and a water-soluble polymer Is known (see, for example, Patent Document 2).

  On the other hand, nano-sized particles (hereinafter referred to as “fine particles”) have properties that are not found in the bulk. For example, as the particles become smaller, the total surface area of the particles becomes larger, so the catalytic performance of the particles becomes higher. Since the melting point is lowered when the particles are nano-sized, the particles can be fired at a low temperature. Furthermore, a large change occurs in the optical properties of the particles depending on the size of the particles. An oxide or the like having a low refractive index becomes transparent when dispersed uniformly in a liquid or the like because light scattering becomes very small when the size is 1/10 or less of the wavelength range of visible light. In the case of metal fine particles, collective vibrations of free electrons in the particles resonate with a specific wavelength, and various colors appear by absorbing light of that wavelength. Due to these characteristics, the fine particles can be used for optical filters, coloring materials, catalysts, antibacterial agents, and the like.

  By controlling the shape and particle diameter of the metal fine particles, the catalytic activity and optical characteristics can be controlled. In the metal fine particles, a phenomenon occurs in which an electric field generated by free electron vibration and an external electric field (light, etc.) resonate (Localized Surface Plasmon Resonance (LSPR)). The surface plasmon resonance causes light absorption in a specific wavelength range. If the resonance wavelength range is a rod shape or flat plate shape, the resonance wavelength varies greatly depending on the aspect ratio of the major axis / minor axis, so that the metal fine particles can be applied to optical filters, heat shield films, color materials, etc. .

While studying the functionalization of micronized cellulose, a new composite material of micronized cellulose and metal microparticles, a composite of tabular silver microparticles and micronized cellulose (flat silver / micronized cellulose composite) was developed. It was done. For example, Patent Document 3 discloses a thickening color-developing antibacterial agent characterized by containing a complex of finely divided cellulose and one or more metals containing at least silver or a compound thereof. . In Patent Document 4, a metal fine particle composed of at least one kind of metal or a compound thereof forms a composite with finely divided cellulose, whereby the transmittance is minimized in the near-infrared region. An infrared shielding material is disclosed.

  In recent years, many display materials capable of repeatedly displaying and erasing information have been developed, and heat, magnetism, and light are mainly used as the display method. Such display materials are designed precisely by controlling, for example, the crystallinity of a low molecular material, the orientation of a liquid crystal material, and the molecular skeleton. Such display materials are often displayed on a card, and are used for point cards, ID cards, and the like, and are widely used. However, a dedicated device is necessary to utilize them. For this reason, there is a demand for a display material that can be used in a simpler manner and is inexpensive and highly visible.

JP 2008-1728 A JP 2012-149114 A Japanese Patent Laying-Open No. 2015-67573 JP 2014-101461 A

In Patent Document 3 and Patent Document 4, detailed description of a resin molded body in which a flat silver / fine cellulose composite (composite) obtained by combining flat metal fine particles and fine cellulose is combined with a resin is described. Absent. When a resin molded body containing a composite is produced, there is a problem in the compatibility between the composite and the resin, and it is difficult to produce an optical filter, a heat shielding film, and the like.
The present invention has been made in view of the above problems, has the property of absorbing or reflecting a specific wavelength region, has high water resistance and moisture resistance, high strength, good dimensional stability, It aims at providing the resin molding which has antibacterial property, and shows an optical characteristic peculiar with a moisture content, its manufacturing method, and a resin composition.

Since energy is required to refine the cellulose fiber at a high concentration and to obtain the refined cellulose at a high concentration, the refined cellulose is generally obtained from a low-concentration dispersion. When compounding with the resin, the concentration of the fine cellulose dispersion is low, and if the solvent in the fine cellulose dispersion is excessive, the concentration of the resin composition is low, for example, a sheet-like molded body is produced. However, energy is required to remove the solvent, and productivity is poor. When concentrating micronized cellulose by centrifugation, it is necessary to concentrate by ultracentrifuge.
Therefore, in order to solve the above problems, as a result of intensive studies by the present inventors, the density of the metal that binds to the composite when the flat metal / micronized cellulose composite (composite) is composited with the resin. Therefore, it is possible to separate the composite with a low gravitational acceleration in a short time and to concentrate the fine cellulose that binds to the composite. It has been found that it is possible to obtain

This invention is based on the said knowledge by the present inventors, and the resin molding which concerns on 1 aspect of this invention for solving the said subject is the synthesis | combination which has at least one of an aqueous dispersion component and an aqueous emulsion component. Including at least a resin and a composite,
The composite is a composite of flat metal fine particles and finely divided cellulose, in which flat metal fine particles and at least one or more refined cellulose are composited, and at least for each refined cellulose. A part or the whole is taken into the flat metal fine particles, and if there is a remainder, it is combined so that the remainder is exposed on the surface of the flat metal fine particles.

In the said resin molding, the solid content rate of the composite containing material mixed with the said synthetic resin is 1 mass% or more and 50 mass% or less, and the solid content rate of a metal is 0.01 mass% or more, 50 It is preferable that it is 0.000 mass% or less.
The resin molded body may have a minimum wavelength in which the transmittance is minimum in a wavelength region of 400 nm to 2500 nm in the transmittance spectrum.
The resin molded body may have a maximum strength of 40 N / mm ² or more and a breaking elongation of 4% or more.

In the said resin molding, the linear expansion coefficient may be 100 * 10 < ^-5 > / K or less.
In the said resin molding, content of the refinement | purification cellulose in the said resin molding may be in the range of 5 mass parts or more and 200 mass parts or less with respect to 100 mass parts of said synthetic resins.
In the resin molded body, at least a synthetic resin having at least one of an aqueous dispersion component and an aqueous emulsion component, and a hydrophilic fiber,
The haze of the resin molded body having a moisture content of 25% or more is HZ ₁ ;
When the haze of the resin molded product having a water content of 8% or less is HZ ₂ , it is preferable that HZ ₁ and HZ ₂ satisfy the following expressions (1) and (2).
HZ ₁ −HZ ₂ ≧ 15 (%) (1)
HZ ₂ ≦ 5 (%) (2)

In the resin molded body, it is preferable that at least one of the aqueous dispersion component and the aqueous emulsion component is anionic or nonionic.
In the resin molded body, the average value of the thickness h of the flat metal fine particles is preferably in the range of 1 nm to 50 nm, and the average value of the particle diameter d is preferably in the range of 2 nm to 1000 nm.
In the resin molded body, the average value of the particle diameter d of the flat metal fine particles is preferably twice or more the average value of the thickness h of the flat metal fine particles.
In the said resin molding, it is preferable that the said metal contains at least any one of gold | metal | money, silver, and copper, It is a resin molding of any one of the Claims 1-7 characterized by the above-mentioned.
In the resin molded body, the refined cellulose is fibrous, has a short axis number average axis diameter of 1 nm to 50 nm, and a long axis number average axis diameter of 0.1 μm to 10 μm. preferable.

In the resin molded body, the refined cellulose may be anion-modified refined cellulose.
In the resin molded body, the refined cellulose may be carboxymethylated cellulose in which at least a part of glucopyranose is carboxymethylated.
In the resin molded body, in the fine cellulose, at least a part of the glucopyranose OH group at the C6 position may be selectively oxidized.
In the resin molded body, the fine cellulose has a minor axis number average axis diameter of 1 nm to 10 nm, a major axis number average axis diameter of 0.2 μm to 2 μm, and a carboxy group content of 0.1 mmol. / G or more and 3.0 mmol / g or less is preferable.
In the resin molded body, the thickness of the resin molded body is preferably in the range of 1 μm to 500 μm.

Moreover, the manufacturing method of the resin molding which concerns on 1 aspect of this invention for solving the said subject is forming the above-mentioned resin molding on a support body by wet coating.
In addition, a resin composition according to one embodiment of the present invention for solving the above problems includes at least a synthetic resin having at least one of an aqueous dispersion component and an aqueous emulsion component, and a composite,
The composite is a composite of flat metal fine particles and finely divided cellulose, in which flat metal fine particles and at least one or more refined cellulose are composited, and at least for each refined cellulose. A part (part) or the whole is incorporated into the flat metal fine particles, and the rest is combined so as to be exposed on the surface of the flat metal fine particles.

According to one embodiment of the present invention, it has the property of absorbing or reflecting a specific wavelength region, has high water resistance and moisture resistance, has high strength, has good dimensional stability, has antibacterial properties, It is possible to provide a resin molded body that exhibits unique optical characteristics depending on the water content. Further, according to one embodiment of the present invention, it is possible to provide a resin molded body that can be used for a display material capable of repeatedly displaying and writing information.
Furthermore, the composite contained in the resin molded product of one embodiment of the present invention is easy to concentrate compared to the refined cellulose alone, and can be efficiently mixed and dispersed with the resin, has high productivity and high strength, and is dimensionally stable. A highly molded resin molding can be obtained.

It is a figure which shows typically an example of the resin molding which concerns on one Embodiment of this invention. It is a figure which shows typically an example of the composite_body | complex which concerns on one Embodiment of this invention. It is a figure (transmission electron microscope image) which shows the result of having observed the composite_body | complex which concerns on one Embodiment of this invention by uranyl dyeing | staining and expanding by the transmission electron microscope (TEM). The result which observed the composite_body | complex which concerns on one Embodiment of this invention with the scanning electron microscope (SEM) is shown, (A) is a scanning electron microscope image, (B) is a schematic diagram of (A). The result which expanded and observed the composite_body | complex which concerns on one Embodiment of this invention with a scanning transmission electron microscope (STEM) is shown, (A) is a scanning transmission electron microscope image, (B) is (A). It is a schematic diagram. The result which expanded and observed the composite_body | complex which concerns on one Embodiment of this invention with a scanning electron microscope (SEM) is shown, (A) is a scanning electron microscope image, (B) is a schematic diagram of (A). It is. It is a figure (transmission electron microscope image) which shows the result of having observed the composite_body | complex which concerns on one Embodiment of this invention from the cross-sectional direction with the transmission electron microscope (TEM). It is a figure which shows the result of having measured the transmittance | permeability of the micronized cellulose aqueous dispersion of Example 1. FIG. It is a figure which shows the evaluation result of the viscosity characteristic of the micronized cellulose aqueous dispersion of Example 1. 2 is a scanning transmission electron microscope (STEM) image of the composite of Example 1. FIG. 10 is a scanning transmission electron microscope (STEM) image of the composite of Example 8.

Embodiments to which the present invention is applied will be described below in detail with reference to the drawings. Note that the drawings used in the following description are for explaining the configuration of the embodiment of the present invention, and the size, thickness, dimensions, and the like of each part shown in the drawings may differ from the actual dimensional relationship.
Drawing 1 is a figure showing typically an example of the resin fabrication object concerning the embodiment of the present invention. The resin molded body of the present embodiment includes at least a synthetic resin having at least one of an aqueous dispersion component and an aqueous emulsion component, and a plate-like metal / micronized cellulose composite (composite),
The composite is a composite of flat metal fine particles and fine cellulose, in which flat metal fine particles (flat metal fine particles) and at least one or more refined cellulose are composited, It is characterized in that at least a part (a part) or the whole of each refined cellulose is incorporated in the flat metal fine particles, and the remainder is compounded so as to be exposed on the surface of the flat metal fine particles. It is a resin molding.

  Here, as a result of studying the compounding of the flat metal / micronized cellulose composite (composite) and the resin, the inventors have a good compatibility between the composite and the resin, and a specific wavelength region. It has been found that it has the property of absorbing or reflecting, has high water resistance and moisture resistance, high strength, good dimensional stability, and exhibits unique optical properties depending on the water content. Furthermore, the composite to be contained in the resin molded body of the present embodiment is easy to concentrate as compared with the refined cellulose alone, can be mixed and dispersed efficiently with the resin, has high productivity and high strength, and has dimensional stability. A high resin molding can be obtained.

  Since high energy is required to refine the cellulose fiber at a high concentration and to obtain the refined cellulose at a high concentration, the refined cellulose is generally obtained from a low-concentration dispersion. When compounding with the resin, the concentration of the fine cellulose dispersion is low, and if the solvent in the fine cellulose dispersion is excessive, the concentration of the resin composition is low, for example, a sheet-like molded body is produced. However, energy is required to remove the solvent, and productivity is poor. When concentrating micronized cellulose by centrifugation, it is necessary to concentrate by ultracentrifuge. However, in the case of a flat metal / micronized cellulose composite (composite), the density of the metal binding to the composite is high and the sedimentation coefficient is large, so the composite is concentrated at the same time as the composite is concentrated at a low centrifugal acceleration in a short time. It is possible to concentrate the refined cellulose bonded to the body, and it is possible to obtain a molded body with higher productivity, higher strength, and higher dimensional stability.

Furthermore, according to one embodiment of the present invention, it is possible to obtain a resin molded body that can be used for a display material that is simple in manufacturing process and display method and that can repeatedly display and write information.
In addition, the resin molded body as used herein refers to various forms such as a film, a sheet, and a structure formed by using a resin composition containing a synthetic resin and a composite having an aqueous dispersion or an aqueous emulsion. Point to. The resin composition contains a synthetic resin and a composite, and refers to a state before a structure is formed or reacted by heating or light.

  Although not particularly limited, the resin molded body 1 according to the present embodiment is preferably formed by aggregating a plurality of resin units. Each resin unit is considered to contain at least a synthetic resin aggregate and a complex that exists so as to cover the surface of the synthetic resin aggregate. Furthermore, the synthetic resin aggregate is formed by aggregating several to several tens of synthetic resins. In other words, the resin molded body according to the present embodiment includes a resin unit including a synthetic resin aggregate formed by aggregating a synthetic resin and a composite formed so as to cover the surface of the synthetic resin aggregate. It is preferable to provide.

Hereinafter, the details of the synthetic resin 11 and the composite 12 described above will be described.
[Complex]
The composite which is one embodiment to which the present invention is applied will be described. The inventors of the present invention have a composite having metal fine particles and fine cellulose (hereinafter referred to as “metal / fine cellulose composite”).
FIG. 2 is a diagram schematically showing a configuration of a complex which is an embodiment to which the present invention is applied. As shown in FIG. 2, the composite 12 of the present embodiment has a flat plate shape in which flat metal fine particles (flat metal fine particles) 21 and at least one or more refined cellulose 22 are combined. It is a composite of metal fine particles and finely divided cellulose, and at least a part (part) or all of each finely divided cellulose 22 is taken into the flat metal fine particles 21, and the rest is the surface 23 of the flat metal fine particles 21. , The back surface 24 and the side surface 25 are combined so as to be exposed.

Since the resin molded body of the present embodiment contains a composite, a resin molded body that selectively absorbs or reflects a specific wavelength region can be obtained, the strength of the resin molded body is improved, and dimensional stability is improved. Can be granted.
Furthermore, since the swelling ratio of the hydrophobic region of the synthetic resin 11 made of an aqueous dispersion or aqueous emulsion is different from that of water, incident light can be scattered on the interface between the hydrophobic regions. Further, by having an appropriate interaction with the synthetic resin 11, the aggregate size of the particles of the synthetic resin 11 is adjusted, or the aggregated interfaces of the synthetic resin 11 are sufficiently bound to each other.

  FIG. 3 is a diagram showing a result of observing the composite body 12 of the present embodiment with uranyl staining and enlarged with a transmission electron microscope (TEM). FIG. 4 shows the result of observing the composite 12 of the present embodiment with a scanning electron microscope (SEM), (A) is a scanning electron microscope image, and (B) is a schematic diagram of (A). . FIG. 5 shows the result of observing the composite 12 of the present embodiment with a scanning transmission electron microscope (STEM) enlarged, (A) is a scanning transmission electron microscope image, and (B) is (A). FIG. FIG. 6 shows the result of magnifying and observing the composite 12 of this embodiment with a scanning electron microscope (SEM), (A) is a scanning electron microscope image, and (B) is a schematic diagram of (A). It is.

  As shown in FIGS. 3 to 6, each refined cellulose 22 includes a part (one end part) 22 a taken in the metal fine particles 21 and a part (other end part) 22 b exposed on the surface of the metal fine particles 21. It consists of and. Then, due to the presence of the one end portion 22 a taken into the metal fine particles 21, the metal fine particles 21 and the respective refined cellulose 22 are in an inseparable state. That is, the metal microparticles 21 and the micronized cellulose 22 are at least partly physically bonded to each other when at least part of the micronized cellulose 22 (that is, one end 22a) is taken into the metal microparticles 21. It is inseparable.

Here, in the composite 12, that at least a part of the micronized cellulose 22 (that is, the one end 22 a) is taken into the metal fine particles 21 along the grain boundary of the metal fine particle unit in the growth stage of the metal fine particles 21. This is synonymous with the state in which the one end 22a of the micronized cellulose 22 is sandwiched.
In the composite 12, the “indivisible” state means that it cannot be separated into the metal fine particles 21 and the finely divided cellulose 22 by a physical method such as a centrifuge.

Note that the composite 12 includes a configuration in which all the parts (the whole) of all the refined cellulose 22 are taken into the metal fine particles 21 and no part exposed on the surface of the metal fine particles 21 exists. Also in the composite body 12 having such a configuration, as shown in FIG. 5, it is possible to confirm the presence of a portion (one end portion) 22 a taken into the metal fine particles 21 in the fine cellulose 22.
The refined cellulose 22 is cellulose having at least one side of its structure on the nanometer order, and the preparation method is not particularly limited. Usually, micronized cellulose has a fiber shape derived from a microfibril structure. Therefore, as the refined cellulose in the composite 12 of the present embodiment, the above-described fibrous one is preferable. By using fibrous refined cellulose, the composite body 12 is controlled in shape and size. Details of the refined cellulose 22 will be described later.

Observation of the complex 12 can be performed, for example, by the following method.
The composite of this embodiment is purified by high-speed cooling centrifugation, etc., cast on a transmission electron microscope grid, stained with uranyl, and observed with a transmission electron microscope. A microscopic image is obtained. According to this transmission electron microscope image, it is possible to observe the flat metal fine particles 21 and the other end portion 22b of the fine cellulose 22 exposed on the surface thereof.
The composite of this embodiment is purified by high-speed cooling centrifugation or the like, and the resulting composite is cast on a silicon wafer plate and subjected to platinum deposition treatment, and then a scanning electron microscope (trade name: S-4800, By observation with Hitachi High-Technologies Corporation, scanning electron microscope images as shown in FIGS. 4 and 6 are obtained. According to this scanning electron microscopic image, it is possible to observe the flat metal fine particles 21 and the other end portion 22b of the fine cellulose 22 exposed on the surface thereof.

Further, by purifying the complex produced by the complex production method of the present embodiment by high-speed cooling centrifugation, etc., casting the obtained complex to a grid, and observing with the above-mentioned scanning transmission electron microscope A scanning transmission electron microscope image as shown in FIG. 5 is obtained. According to this scanning transmission electron microscope image, it is possible to observe the flat metal fine particles 21 and one end of the refined cellulose 22a taken into the flat metal fine particles 21.
In addition, the composite of this embodiment is purified by high-speed cooling centrifugation or the like, and the resulting composite is cast on a grid and observed with the above-described scanning electron microscope in an undeposited state. Elemental mapping by line analysis is performed, and the detection of carbon by the flat metal fine particles 21 and the refined cellulose 22 can confirm the composite of the flat metal fine particles 21 and the refined cellulose 22.

Generally, a metal surface and a solvent do not have a strong affinity, and particles will aggregate and precipitate as they are. However, the composite of the present embodiment is reduced in the presence of metal ions and fine cellulose, whereby metal atoms are generated, and metal fine particles are generated through nucleation and growth. In this process, the metal fine particles and the finely divided cellulose fibers interact to affect the shape and aggregation of the metal fine particles, and it is considered that the composite 12 having a controlled shape and size can be obtained.
In the composite 12 thus obtained, at least a part or all of the fine cellulose 22 is taken into the flat metal fine particles 21 and the rest is exposed on the surface of the flat metal fine particles 21. To do. In the composite of this embodiment, it is preferable that the flat metal fine particles 21 and the fine cellulose cellulose 22 are inseparable from the viewpoint of dispersion stability.

(Metal fine particles)
By controlling the shape and particle size of the metal fine particles in the composite, it is possible to control the catalytic activity and optical characteristics. Free electrons on the surface of the metal fine particles may collectively vibrate due to an external electric field such as light. Since electrons are charged particles, an electric field is generated around them when they vibrate. A phenomenon in which a phenomenon in which an electric field generated by free electron vibration and an external electric field (light, etc.) resonate occurs is called localized surface plasmon resonance (LSPR). This LSPR causes light absorption in a specific wavelength range. If the resonance wavelength range is a rod shape or flat plate shape, the resonance wavelength varies greatly depending on the aspect ratio of the major axis / minor axis, so that the metal fine particles can be applied to optical filters, heat shield films, color materials, etc. .

  Among the metal nanoparticles having such an anisotropic shape, silver nanoparticles are particularly expected to be applied. For example, it is known that spherical silver nanoparticles having a particle diameter of several nanometers to several tens of nanometers have a yellowish color due to absorption in the vicinity of a wavelength of 400 nm by the LSPR. However, the anisotropically grown silver nanoparticles are not limited to this, and it is known that, for example, tabular silver nanoparticles are red-shifted in absorption peak. At this time, it has been confirmed that the absorption peak shifts to the longer wave side as the aspect ratio (that is, particle diameter / particle thickness) of the tabular silver nanoparticles increases. That is, the tabular silver nanoparticles can be used as an optical material that absorbs an arbitrary wavelength. Moreover, if the absorption wavelength is controlled in the visible light region, flat silver nanoparticles exhibiting a vivid color tone such as red and blue in addition to yellow can be obtained, and use as a functional color material can be expected. Further, depending on the aspect ratio of the tabular silver nanoparticles, the absorption peak can be shifted to the near infrared region outside the visible light region.

Note that in this specification, visible light refers to electromagnetic waves having a wavelength range of approximately 400 nm to 700 nm, and near infrared refers to electromagnetic waves having a wavelength range close to visible light (approximately 700 nm to 2500 nm) among infrared rays. . This near-infrared ray has a property close to visible light. In particular, it is known that light in the wavelength region of 700 nm to 1200 nm contained in sunlight is easily absorbed by the object surface and converted into thermal energy.
Such a near-infrared absorbing material is a functional material with high added value because it can shield heat rays. For example, by providing a layer containing a near-infrared absorbing material on a building or a car window, it is possible to provide a heat shielding effect. That is, since a power saving effect due to an increase in cooling efficiency can be expected, it can also contribute to the improvement of the power shortage problem in summer.

In the composite of this embodiment, the flat metal fine particles are flat metal fine particles, and in this embodiment, the fine particles are particles having a volume particle diameter of 10 μm or less. In the composite of this embodiment, “flat plate” is a plate-like particle.
Here, as shown in FIG. 2, the shape of the front surface 23 or the back surface 24 of the flat metal fine particles of the composite 12 is a circle having a diameter d (equivalent circle diameter). The diameter d is the particle diameter of the composite 12. The diameter d with respect to the thickness h of the flat metal fine particles of the composite 12 is defined as the aspect ratio (d / h) of the composite 12. The “plate shape” of the plate-like metal fine particles of the composite 12 indicates a plate-like particle, and the average value of the aspect ratio (d / h) is 1.1 or more.

In addition, although the shape of the surface 23 and the back surface 24 of the composite_body | complex 12 is not specifically limited, Usually, they are polygons, such as a hexagon and a triangle. When the front surface 23 and the back surface 24 are polygons, ellipses, or the like, the diameter d (equivalent circle diameter) is calculated on the assumption that the area of the front surface 23 or the front surface 24 is equal.
Moreover, the surface 23 and the back surface 24 of the composite 12 may have either large area, and both surfaces do not need to be parallel.
From the viewpoint of controlling the optical characteristics, the shape of the flat metal fine particles 21 is preferably a flat plate, and the particle diameter d, thickness h, and aspect ratio thereof are preferably within the following ranges. The particle diameter d, thickness h, and aspect ratio of the flat metal fine particles 21 are equal to the particle diameter d, thickness h, and aspect ratio of the composite 12.

The average value of the particle diameter d of the flat metal fine particles 21 is preferably 2 nm or more and 1000 nm or less, more preferably 20 nm or more and 500 nm or less, and further preferably 20 nm or more and 400 nm or less.
The average value of the thickness h of the flat metal fine particles 21, that is, the average value of the distance h between the front surface 23 and the back surface 24 is preferably 1 nm or more and 100 nm or less, and more preferably 5 nm or more and 50 nm or less.
In addition, said average value is calculated | required, for example by measuring 100 particle | grains.
The aspect ratio (average value of d / average value of h) of the flat metal fine particles 21 is 1.1 or more, preferably 2.0 or more, and more preferably 2.0 or more and 100 or less. More preferably, it is 2.0 or more and 50 or less.

The composite 12 of the present embodiment can change the color tone by arbitrarily changing the average value of the particle diameter d and controlling the aspect ratio. Moreover, the composite_body | complex 12 should just contain the metal microparticle 21 and the refined cellulose 22, and may contain the other component.
The shape and size of the metal fine particles in the present embodiment can be evaluated using a scanning electron microscope, a transmission electron microscope, and a scanning transmission electron microscope.
Examples of the method for measuring the particle diameter d and thickness h of the flat metal fine particles and the method for calculating the aspect ratio include the following methods.

(1) Particle diameter measurement method The dispersion containing the composite 12 is cast on a copper grid with a support film for transmission electron microscope observation and air-dried, and then observed with a scanning transmission electron microscope. A scanning transmission electron microscope image as shown is obtained. The diameter of the flat metal particles in the scanning transmission electron microscope image approximated by a circle is calculated as the particle diameter in the plane direction. The average value is obtained by measuring 100 particles.

(2) Thickness measurement method As shown in FIG. 7, a dispersion containing the composite 12 is cast on a polyethylene terephthalate (PET) film 26, air-dried, and fixed with an embedding resin 27. By cutting in the direction and observing with a transmission electron microscope, a transmission electron microscope image as shown in FIG. 7 is obtained. FIG. 7 is a diagram (transmission electron microscope image) showing the result of observation of the flat metal fine particles 21 from the cross-sectional direction using a transmission electron microscope. The thickness of the flat metal fine particles in the transmission electron microscope is calculated as the thickness perpendicular to the plane direction. The average value is obtained by measuring 100 particles.

(3) Aspect Ratio Calculation Method The average value of the diameter d (equivalent circle diameter) with respect to the average value of the thickness h of the tabular metal fine particles 21 and the aspect ratio of the tabular metal fine particles 21 (d (Average value of / average value of h)).
The method for measuring the particle diameter and thickness of the flat metal fine particles and the method for calculating the aspect ratio are examples, and the method for measuring the particle diameter and thickness of the flat metal fine particles and the calculation of the aspect ratio in the present embodiment. The method is not particularly limited to these.

  The metal or metal compound which comprises the flat metal fine particle 21 is not specifically limited, Arbitrary metals or metal compounds can be used according to a use. Examples of the metal or metal compound constituting the flat metal fine particles 21 include gold, silver, copper, aluminum, iron, platinum, zinc, palladium, ruthenium, iridium, rhodium, osmium, chromium, cobalt, nickel, manganese, and vanadium. And metals such as molybdenum, gallium, and aluminum, metal salts, metal complexes and alloys thereof, oxides, and double oxides. Among them, it is preferable to include at least one of gold, silver, and copper. In particular, when at least silver is included, the composite 12 can shield light having a wavelength from the visible light region to the near infrared region, and has antibacterial properties. Can also be given. The ratio of the metal contained in the composite 12 is not particularly limited.

(Refined cellulose)
The refined cellulose may have at least one side of its structure as long as nanometer order, and the preparation method is not particularly limited. Usually, since the refined cellulose has a fiber shape derived from a microfibril structure, the refined cellulose used in the method for producing a composite according to the present embodiment is preferably a fiber in the following range. By using fibrous fine cellulose, it is possible to produce a composite with a more controlled shape and size.

The refined cellulose 22 contained in the composite 12 in the resin molded body 1 of the present embodiment can control the particle diameter and shape by controlling the growth of the generated metal fine particles. Further, in the resin molded body, dimensional stability can be imparted with the improvement of the strength of the resin molded body.
Furthermore, since the swelling ratio of the hydrophobic region of the synthetic resin 11 made of an aqueous dispersion or aqueous emulsion is different from that of water, incident light can be scattered on the interface between the hydrophobic regions. Further, by having an appropriate interaction with the synthetic resin 11, the aggregate size of the particles of the synthetic resin 11 is adjusted, or the aggregated interfaces of the synthetic resin 11 are sufficiently bound to each other. In addition, if the minor axis diameter of the refined cellulose is too large, scattering by the light interface occurs regardless of the water content, and the haze of the resin molded body 1 is increased. Therefore, the minor axis diameter of the refined cellulose 22 is sufficiently large. Small is preferable.

  The kind of plant cellulose used as a raw material for fine cellulose is not particularly limited. As a raw material of the fine cellulose, for example, cotton linter, bamboo, hemp, bagasse, kenaf and the like can be used in addition to wood-based natural cellulose. Moreover, as a raw material of refined cellulose, for example, non-wood based natural cellulose such as bacterial cellulose, squirt cellulose, and valonia cellulose, and regenerated cellulose represented by rayon fiber and cupra fiber can be used. Preferably, natural cellulose having crystalline form I is desirable because of its high material properties such as mechanical properties, thermal properties and chemical resistance.

Although it does not specifically limit as a refinement | purification processing method of a cellulose, For example, the method of refinement | miniaturizing using the chemical modification | denaturation and mechanical treatment of a cellulose other than the mechanical processing by a grinder is mentioned.
Bacterial cellulose can also be used as refined cellulose. Further, finely regenerated cellulose fibers obtained by dissolving various natural celluloses in various cellulose solvents and then performing electrospinning may be used.
The chemical modification method of cellulose is not particularly limited. For example, N-oxyl compounds such as 2,2,6,6-tetramethyl-1-piperidine-N-oxy radical (hereinafter referred to as “TEMPO”) are used. The oxidation method, the dilute acid hydrolysis treatment, the enzyme treatment, and the like that have been used in combination with the mechanical treatment can be used.

  The refined cellulose used in the present embodiment is preferably anion-modified refined cellulose. Although the anion-modified fine cellulose is not particularly limited, for example, anion-modified cellulose such as carboxylated cellulose (hereinafter referred to as “oxidized cellulose”), carboxymethylated cellulose, and phosphate esterified cellulose is defibrated. Can be obtained by: In the anion-modified micronized cellulose, the introduced functional groups such as carboxy group, carboxymethyl group, and phosphate group serve as a base point in the production of metal fine particles, and it is easy to control the shape and size of the composite.

Carboxymethylated cellulose can be obtained from a cellulose raw material by a known method. For example, an etherification agent such as monochloroacetic acid and a catalyst, an alkali metal hydroxide such as sodium hydroxide or potassium hydroxide, is added to cellulose raw material, and water or a solvent mainly composed of lower alcohol such as methanol, ethanol, isopropyl alcohol, etc. It is obtained by reacting below.
The carboxymethylated cellulose is sufficient if at least a part of glucopyranose is carboxymethylated, and the degree of substitution of carboxymethylcellulose is preferably 0.01 or more and 0.60 or less.

  In particular, as shown in the method of Patent Document 4, in the oxidation reaction using N-oxyl compounds such as TEMPO, the primary hydroxyl group at the 6th position of the glucopyranose unit of the cellulose molecular chain on the crystal surface is highly selective. Oxidized cellulose that has been converted to a carboxy group via an aldehyde group can be obtained. Since an electrostatic repulsive force acts between celluloses having a carboxy group introduced on the crystal surface in this way, cellulose single nanofibers (hereinafter referred to as “CSNF”) dispersed to microfibril units in an aqueous medium. .) Can be obtained. Therefore, when CSNF is used, it is easy to control the shape and size of the composite.

The oxidation reaction using the N-oxyl compound will be described in detail later.
If this CSNF is used, a composite whose shape and size are sufficiently controlled can be produced. CSNF that is fibrous and has a uniform minor axis diameter is suitable for controlling the size and shape of the composite. CSNF regularly has carboxy groups on the fiber surface. This carboxy group is suitable for producing a complex because a metal ion is coordinated when the complex is produced and becomes a starting point for producing the complex.
Since CSNF selectively oxidizes the hydroxyl group at the C6 position on the microfibril surface of cellulose, the cellulose maintains type I crystals and has almost no decrease in crystallinity. be able to. Further, since the ionicity can be controlled by the amount of carboxy groups introduced by the TEMPO oxidation reaction conditions, and the amount of carboxy groups introduced by the TEMPO oxidation reaction conditions can be controlled, the synthetic resin 11 applied to the resin molded body 1 is used. It is possible to adjust the charge amount derived from the carboxy group according to the above. Cellulose has three hydroxyl groups per glucose unit, and has a high hydrophilicity because it has a structure in which a number of hydroxyl groups are exposed on the microfibril surface by being fibrillated to the nano level. The swelling rate of becomes extremely high.

Therefore, by using CSNF, the resin molded body 1 has characteristics of high strength, high elastic modulus, low linear expansion coefficient, and high heat resistance. Furthermore, since ionicity control is possible, it is preferable to use CSNF also in the control of optical characteristics by moisture content.
The viscosity characteristics of the micronized cellulose are preferably as follows. 0.5 wt% dispersion of the fine cellulose (25 ° C.) is, 30 mPa · s or more 2000 mPa · s or less at a shear rate of ^{1s -1,} 200mPa · ^20mPa · s or more at a shear rate of 100s ^-1 It is preferable that it is s or less. More preferably, when the viscosity (25 ° C.) of the 0.5 mass% dispersion of fine cellulose is 100 mPa · s to 1000 mPa · s when the shear rate is 1 s ⁻¹ , and the shear rate is 100 s ⁻¹ . 30 mPa · s or more and 80 mPa · s or less.

  When the viscosity characteristics of the refined cellulose are within the above range, the refined cellulose is reduced in viscosity, and therefore can be used at a high concentration, and the composite can be produced with high productivity. If the viscosity characteristics are within the above range, the crystal structure and the surface structure are maintained, and the carboxy group is regularly used as a starting point for complexing with the metal fine particles, so that the complex is stably controlled in shape. Can be manufactured. Furthermore, if the viscosity characteristic is within the above range, the metal salt and the refined cellulose can be uniformly mixed in the step b described later, and the reduction reaction can be promoted uniformly in the step c.

The refined cellulose preferably has a minor axis number average axis diameter of 1 nm to 50 nm, a major axis number average axis diameter of 0.1 μm to 10 μm, and a minor axis number average axis diameter of 1 nm to 10 nm. The number average axis diameter of the major axis is more preferably 0.2 μm or more and 2 μm or less.
If the number average axis diameter of the minor axis of the micronized cellulose is less than 1 nm, a highly crystalline rigid micronized cellulose structure cannot be obtained, and it becomes difficult to obtain a composite whose size and shape are sufficiently controlled. . Moreover, it becomes difficult to obtain the resin molded body 1 having high strength and good dimensional stability. On the other hand, when the number average axis diameter of the minor axis of the refined cellulose exceeds 50 nm, the viscosity of the dispersion of the refined cellulose is increased and the operability is deteriorated. In the step b described later, the metal salt and the refined cellulose are made uniform. In step c, the reduction reaction cannot proceed uniformly, and it is difficult to obtain a complex whose size and shape are sufficiently controlled. In addition, the strength of the resin molded body 1 may be reduced.

If the number average axis diameter of the major axis of the fine cellulose is less than 0.1 μm, it is difficult to obtain a composite whose shape and size are controlled. On the other hand, if the number average axis diameter of the major axis of the refined cellulose exceeds 10 μm, the viscosity of the dispersion of the refined cellulose becomes high and the operability is deteriorated. It is difficult to uniformly mix, and in step c, the reduction reaction cannot proceed uniformly, and it is difficult to obtain a complex whose size and shape are sufficiently controlled. It becomes difficult to mix the synthetic resin 11 and the composite-containing material.
The number average axis diameter of the minor axis of the micronized cellulose is obtained as an average value obtained by measuring the minor axis diameter (minimum diameter) of 100 fibers by observation with a transmission electron microscope and atomic force microscope. On the other hand, the number average axis diameter of the major axis of the fine cellulose is obtained as an average value obtained by measuring the major axis diameter (maximum diameter) of 100 fibers by observation with a transmission electron microscope and observation with an atomic force microscope.

Although the measuring method is not specifically limited about the short axis diameter of a refined cellulose used by this embodiment, and a long axis diameter, For example, it can measure with the following method. A solution obtained by dispersing finely divided cellulose in water so that the solid content concentration is in the range of 0.001% by mass or more and 0.01% by mass or less is developed on mica and naturally dried. Then, the minor axis diameter and major axis diameter of the refined cellulose can be confirmed (measured) by observing the refined cellulose with a transmission electron microscope.
The crystallinity of the fine cellulose is preferably 70% or more.
If the crystallinity of the micronized cellulose is less than 70%, a rigid micronized cellulose structure cannot be obtained, and it becomes difficult to stably produce a composite, and the strength of the resin molded body 1 is reduced. There is.

The amount of carboxy groups in the refined cellulose is preferably 0.1 mmol or more and 3.0 mmol or less, and more preferably 0.5 mmol or more and 2.0 mmol or less per 1 g of dry mass of the refined cellulose.
When the amount of carboxy groups in the micronized cellulose is less than 0.1 mmol / g, the dispersibility is poor. On the other hand, when the amount of carboxy groups in the refined cellulose is 3.0 mmol / g or less, the crystal structure of the refined cellulose is sufficiently retained, the shape control performance is good, and the optical property is determined by the moisture content of the resin molded body 1. Easy to control characteristics.

When the cellulose fiber is dispersed to the microfibril unit, the light transmittance at a wavelength of 660 nm is increased. In a dispersion having a solid content concentration of 1%, the refined cellulose preferably has an optical path length of 1 cm, a wavelength of 660 nm, and a light transmittance of 80% or more using the dispersion medium as a reference.
Although refined cellulose is not specifically limited, What was manufactured with the following method can be used.

(Oxidation process)
Examples of natural cellulose used as a raw material for fine cellulose include wood pulp such as mechanical pulp, chemical pulp, and semi-chemical pulp. Specifically, bleached and unbleached kraft wood pulp, hydrolyzed kraft wood pulp, sulfite wood pulp, etc., as well as used paper, bacterial cellulose, valonia cellulose, squirt cellulose, cotton cellulose, hemp cellulose and mixtures thereof are used. be able to. Moreover, you may use any of the substance which processed these physically and chemically. It is preferable to use various wood pulps as a raw material from the viewpoint of ease of material procurement and price.

  In the presence of an N-oxyl compound, as a method for oxidizing cellulose using a co-oxidant, alcoholic primary carbon is selectively oxidized while maintaining the crystal structure of cellulose as much as possible under relatively mild conditions in water. Is possible. Examples of the N-oxyl compound include TEMPO, 2,2,6,6-tetramethyl-4-hydroxypiperidine-1-oxyl, 4-methoxy-2,2,6,6-tetramethylpiperidine-N—. Examples include oxyl, 4-ethoxy-2,2,6,6-tetramethylpiperidine-N-oxyl, 4-acetamido-2,2,6,6-tetramethylpiperidine-N-oxyl. Among these, TEMPO is preferable.

The amount of the N-oxyl compound used is not particularly limited as long as it is an amount as a catalyst. Usually, the usage-amount of an N-oxyl compound is about 0.01 mass%-about 5.0 mass% with respect to the whole quantity of solid content of the wood type natural cellulose to oxidize.
Examples of the method for oxidizing cellulose using an N-oxyl compound include a method in which wood-based natural cellulose is dispersed in water and oxidized in the presence of an N-oxyl compound. At this time, it is preferable to use a co-oxidant together with the N-oxyl compound. In this case, in the reaction system, the N-oxyl compound is sequentially oxidized by a co-oxidant to produce an oxoammonium salt, and cellulose is oxidized by the oxoammonium salt. According to such oxidation treatment, the oxidation reaction proceeds smoothly even under mild conditions, and the introduction efficiency of the carboxy group is improved. When the oxidation treatment is performed under mild conditions, it is easy to maintain the crystal structure of cellulose.

As a co-oxidant, halogen, hypohalous acid, halohalic acid or perhalogenic acid, or a salt thereof, halogen oxide, nitrogen oxide, peroxide, etc., as long as it can promote the oxidation reaction Any oxidizing agent can be used. From the standpoint of availability and reactivity, sodium hypochlorite is preferred as the co-oxidant.
The amount of the co-oxidant used is not particularly limited as long as it is an amount capable of promoting the oxidation reaction of cellulose. Usually, it is about 1% by mass to 200% by mass with respect to the total solid content of the wood-based natural cellulose to be oxidized.

Along with the N-oxyl compound and the co-oxidant, at least one compound selected from the group consisting of bromide and iodide may be further used in combination. Thereby, the oxidation reaction of a cellulose can be advanced smoothly and the introduction efficiency of a carboxy group can be improved.
As such a compound, sodium bromide or lithium bromide is preferable, and sodium bromide is more preferable from the viewpoint of cost and stability.
The amount of the compound used is not particularly limited as long as it is an amount capable of promoting the oxidation reaction of cellulose. Usually, it is about 1% by mass to 50% by mass with respect to the total solid content of the wood-based natural cellulose to be oxidized.

The pH of the reaction system during the oxidation reaction of cellulose is preferably 9-11.
When the pH is 9 or more, the reaction can be efficiently advanced. It is known that the oxidation efficiency by the N-oxyl compound is significantly reduced when the pH is out of the range. In the above oxidation treatment, as the oxidation proceeds, a carboxy group is generated, which lowers the pH in the reaction system. Therefore, the pH of the reaction system is preferably maintained at 9 to 11 during the oxidation treatment. Examples of a method for maintaining the pH of the reaction system at 9 to 11 include a method of adding an alkaline aqueous solution in accordance with a decrease in pH.

Examples of the alkaline aqueous solution include sodium hydroxide aqueous solution, lithium hydroxide aqueous solution, potassium hydroxide aqueous solution, ammonia aqueous solution, tetramethylammonium hydroxide aqueous solution, tetraethylammonium hydroxide aqueous solution, tetrabutylammonium hydroxide aqueous solution, and benzyltrimethylammonium hydroxide. Examples include organic alkalis such as aqueous solutions. Among these, an aqueous sodium hydroxide solution is preferable from the viewpoint of cost and the like.
The reaction temperature of the oxidation reaction of cellulose is preferably 4 ° C. or higher and 50 ° C. or lower, and more preferably 30 ° C. or higher and 50 ° C. or lower.

  Although the oxidation reaction itself with a normal N-oxyl compound proceeds sufficiently even in the region of 4 ° C. or more and 50 ° C. or less, when the oxidation reaction is performed in the temperature region of 30 ° C. or more and 50 ° C. or less, the crystal structure of the cellulose fiber is maintained. It was found that the dispersion of fine cellulose obtained as it was was reduced in viscosity. This is because the amorphous region periodically exists in the major axis direction of the cellulose microfibril, so that the oxidation reaction by the N-oxyl compound proceeds to the amorphous region, and the generated glucuronic acid unit has pH 9 in the reaction temperature region. It is considered that it is decomposed because it is unstable under the conditions of ˜11, and as a result, shortening of the fiber proceeds. When the reaction temperature exceeds 50 ° C., sodium hypochlorite self-decomposes due to side reaction, so that the oxidation reaction itself stops.

  The degree of oxidation in the oxidation treatment of cellulose can be appropriately set in consideration of the reaction temperature, the desired amount of carboxy groups, and the like. However, it is preferable that at least the amount of sodium hydroxide used in the oxidation reaction is 1.0 mmol / g or more and 5.0 mmol / g or less per dry mass of natural cellulose as a raw material. When the amount of sodium hydroxide added is less than 1.0 mmol / g, the amount of carboxy groups introduced is small, and sufficient electrostatic repulsion between microfibrils required for dispersion as CSNF cannot be obtained. On the other hand, if the amount of sodium hydroxide added exceeds 5.0 mmol / g, decomposition other than the amorphous region proceeds, the microfibril surface structure is lost, and the yield before and after the oxidation treatment is significantly reduced.

The oxidation reaction with the N-oxyl compound can be stopped by adding a primary alcohol to the reaction system. At this time, the pH of the reaction system is preferably maintained within the above range. The primary alcohol to be added is preferably a low-molecular-weight primary alcohol such as methanol, ethanol, or propanol in order to quickly terminate the reaction, and ethanol is particularly preferable from the viewpoint of safety of by-products generated by the reaction. .
The reaction solution after the oxidation treatment may be directly subjected to a refinement process, but in order to remove a catalyst such as an N-oxyl compound, impurities, etc., the oxidized cellulose contained in the reaction solution is recovered and washed with a washing solution. It is preferable. Oxidized cellulose can be collected by a known method such as filtration using a glass filter or a nylon mesh having a 20 μm pore size. Distilled water is preferable as the cleaning liquid used for cleaning the oxidized cellulose.

(Miniaturization process)
The micronization step is a step of defibrating oxidized cellulose by light mechanical processing to obtain a micronized cellulose dispersion.
In the method of refining cellulose, first, a solvent is added to cellulose and suspended.
Although it does not specifically limit as a solvent, The thing similar to the solvent in which refined cellulose is disperse | distributed can be used, Among these, water is especially preferable. If necessary, the pH of the suspension may be adjusted in order to improve the dispersibility of the cellulose and the refined cellulose to be produced. Examples of the alkaline aqueous solution used for adjusting the pH include the same alkaline aqueous solution as mentioned in the description of the oxidation step of oxidized cellulose.
Subsequently, the cellulose is refined by subjecting the suspension to physical defibrating treatment.

Examples of physical fibrillation treatment include high-pressure homogenizer, ultra-high-pressure homogenizer, ball mill, roll mill, cutter mill, planetary mill, jet mill, attritor, grinder, juicer mixer, homomixer, ultrasonic homogenizer, nanogenizer, underwater collision And other mechanical treatments. By performing such physical fibrillation treatment on, for example, TEMPO oxidized cellulose, the cellulose in the suspension is refined, and a dispersion of CSNF having a carboxy group on the fiber surface can be obtained.
Since the refined cellulose obtained as described above maintains the crystal structure, the composite can be stably produced.

The obtained dispersion liquid can be used as a reaction field for reducing and precipitating metal fine particles as it is, or by diluting, concentrating, solvent substitution and the like as necessary.
The finely divided cellulose dispersion liquid may contain other components than the components used for adjusting the cellulose and pH, as long as the effects of the present invention are not impaired. Other components are not particularly limited, and can be appropriately selected from known additives depending on the application. Specifically, as other components, organometallic compounds such as alkoxysilanes or hydrolysates thereof, inorganic layered compounds, inorganic needle minerals, antifoaming agents, inorganic particles, organic particles, lubricants, antioxidants Agents, antistatic agents, ultraviolet absorbers, stabilizers, magnetic powders and the like. The composite may be produced after mixing the aqueous dispersion component and the aqueous emulsion component with the finely divided cellulose dispersion.

[Production method of composite]
Although the composite of this embodiment is not specifically limited, For example, it can manufacture with the following method.
a) preparing a solution or dispersion containing at least one type of micronized cellulose and preparing a micronized cellulose-containing liquid;
b) preparing a solution or dispersion containing at least one kind of metal salt and at least one kind of micronized cellulose, and preparing a metal salt and a micronized cellulose-containing liquid; When,
c) reducing the metal ions in the metal salt and the refined cellulose-containing liquid, preparing a reaction liquid to obtain a complex dispersion, and a reaction liquid preparation step,
Have
The refined cellulose used for producing the composite is preferably anion-modified refined cellulose. Since the metal ion is reduced in a state where the metal ion is coordinated to the functional group introduced by anion modification, and metal fine particles are generated based on the metal ion, the composite and shape control are facilitated.

(Process a: Refined cellulose dispersion preparation process)
In the composite manufacturing method of the present embodiment, in step a, at least one type of fine cellulose dispersion is prepared.
The solid content concentration of the refined cellulose dispersion in at least one kind of refined cellulose dispersion is not particularly limited, but is preferably 0.01% by mass or more and 90% by mass or less, and more preferably 0.1% by mass or more and 50% by mass. % Or less is more preferable.
When the solid content concentration of the fine cellulose dispersion is less than 0.01% by mass, it is difficult to control the shape of the composite. On the other hand, when the solid content concentration of the fine cellulose dispersion exceeds 90% by mass, the viscosity of the fine cellulose dispersion increases, and in step b (metal salt and fine cellulose-containing liquid preparation step), metal salt and fine It becomes difficult to uniformly mix the cellulose with cellulose, and in the step c (reaction liquid preparation step), the reduction reaction cannot proceed uniformly.

The solvent for dispersing the fine cellulose is not particularly limited as long as the fine cellulose is sufficiently dissolved or dispersed. From the viewpoint of environmental load, it is preferable to use water as the solvent.
From the viewpoint of the dispersibility of the fine metal particles and fine cellulose, it is preferable to use water or a hydrophilic solvent as the solvent. Although it does not specifically limit as a hydrophilic solvent, Alcohols, such as methanol, ethanol, isopropanol, are preferable.
The pH of at least one type of fine cellulose dispersion is not particularly limited, but is preferably pH 2 or more and pH 12 or less.

(Process b: Metal salt and refined cellulose containing liquid preparation process)
In the composite production method of the present embodiment, in step b, a solution or dispersion containing at least one metal salt and at least one refined cellulose is prepared, and the metal salt and the refined cellulose-containing solution are prepared. prepare.
A method for preparing a solution or dispersion containing at least one metal salt and at least one micronized cellulose is not particularly limited. For example, a solution or dispersion containing at least one type of fine cellulose (a fine cellulose dispersion) and a solution containing at least one metal salt (metal salt-containing solution) are prepared, and the fine cellulose dispersion is prepared. While stirring the liquid, it can be prepared by adding a metal salt-containing solution to the finely divided cellulose dispersion. Further, a solid metal salt may be added directly to the fine cellulose dispersion, or the fine cellulose dispersion may be added to the metal salt-containing solution.

Metal salts include silver nitrate, silver chloride, silver oxide, silver sulfate, silver acetate, silver nitrite, silver chlorate, chloroauric acid, sodium gold chloride, potassium gold chloride, platinum chloride, platinum oxide and platinum oxide. It is preferable that there is at least one selected. These metal salts may be used individually by 1 type, and may be used in combination of 2 or more types.
When preparing a metal salt-containing solution, the solvent used in the metal salt-containing solution is not particularly limited as long as the metal salt is sufficiently dispersed or dissolved.
From the viewpoint of environmental load, it is preferable to use water as the solvent.

From the viewpoint of solubility of the metal salt, it is preferable to use water or a hydrophilic solvent as the solvent. Although it does not specifically limit as a hydrophilic solvent, Alcohols, such as methanol, ethanol, isopropanol, are preferable.
Further, the concentration of the metal salt in the metal salt-containing solution is not particularly limited.
The concentration of the metal salt and the metal salt in the fine cellulose dispersion is not particularly limited, but is preferably 0.002 mmol / L or more and 20.0 mmol / L or less. In particular, when CSNF is used as micronized cellulose, the metal ion is coordinated to the carboxy group present on the fiber surface. Is preferred. If the concentration of metal salt (concentration of metal ions) exceeds the amount of carboxy groups present on the surface of the refined cellulose, CSNF may aggregate.

The solvent used for the metal salt and the refined cellulose-containing liquid is not particularly limited as long as the refined cellulose is sufficiently dispersed or dissolved.
From the viewpoint of environmental load, it is preferable to use water as the solvent.
From the viewpoint of the dispersibility of the composite, it is preferable to use water or a hydrophilic solvent as the solvent. Although it does not specifically limit as a hydrophilic solvent, Alcohols, such as methanol, ethanol, isopropanol, are preferable.
The solid content concentration of the refined cellulose in the metal salt and the refined cellulose dispersion is not particularly limited, but is preferably 0.01% by mass or more and 90% by mass or less, and 0.1% by mass or more and 50% by mass or less. More preferably.

If the solid content concentration of the refined cellulose is less than 0.01% by mass, it is difficult to control the shape of the composite. On the other hand, when the solid content concentration of the refined cellulose exceeds 90% by mass, the viscosity of the refined cellulose dispersion increases, and it becomes difficult to uniformly mix the metal salt and the refined cellulose in step b. In this case, the reduction reaction cannot proceed uniformly. When the composite is used as a conductive material, it becomes difficult to sinter at a low temperature when the solid content concentration of the fine cellulose becomes high, and a step of removing the fine cellulose is necessary.
The solvent for the metal salt and the refined cellulose-containing liquid is not particularly limited as long as the refined cellulose is sufficiently dissolved or dispersed.

From the viewpoint of environmental load, it is preferable to use water as the solvent.
From the viewpoint of the dispersibility of the fine metal particles and fine cellulose, it is preferable to use water or a hydrophilic solvent as the solvent. Although it does not specifically limit as a hydrophilic solvent, Alcohols, such as methanol, ethanol, isopropanol, are preferable.
The pH of the metal salt and the refined cellulose-containing liquid is not particularly limited, but is preferably pH 2 or more and pH 12 or less.
The temperature of the metal salt and the refined cellulose-containing liquid is not particularly limited, but when water is used as the solvent, it is preferably 4 ° C. or higher and 100 ° C. or lower.

(Process c: Reaction liquid preparation process)
In the composite production method of the present embodiment, in step c, metal ions in the metal salt and the refined cellulose-containing liquid are reduced, and a reaction liquid is prepared to obtain a composite dispersion.
The method for reducing the metal ions in the metal salt and the refined cellulose-containing liquid is not particularly limited, and a known method can be used. For example, a method using a reducing agent, ultraviolet rays, electron beams, liquid plasma, or the like can be employed. A known reducing agent can be used as a reducing agent used for reducing metal ions.

Examples of the reducing agent include metal hydride-based, borohydride-based, borane-based, silane-based, hydrazine and hydrazide-based reducing agents. In general, in the liquid phase reduction method, sodium borohydride, dimethylamine borane, sodium citrate, ascorbic acid and alkali metal ascorbate, hydrazine, and the like are used as the reducing agent.
The amount of reducing agent added in the metal salt and refined cellulose-containing liquid (reducing agent concentration) is not particularly limited, but should be equal to or greater than the concentration of metal salt and metal salt in the refined cellulose-containing liquid. Is preferable, and more preferably 0.002 mmol / L or more and 2000 mmol / L or less.

If the concentration of the reducing agent in the metal salt and the refined cellulose-containing liquid is equal to or less than the concentration of the metal salt in the metal salt and the refined cellulose-containing liquid, unreduced metal ions remain in the metal salt and the refined cellulose-containing liquid. Resulting in.
Although there is no particular limitation on the method of adding the reducing agent in the case of reducing the metal ion in the liquid containing the metal salt and the refined cellulose using the reducing agent, the reducing agent is dissolved or dispersed in a solvent such as water in advance, The solution or dispersion may be added to the metal salt and refined cellulose-containing solution.

Moreover, the addition rate of the reducing agent with respect to the metal salt and the refined cellulose-containing liquid is not particularly limited, but it is preferably added by a method in which the reduction reaction proceeds uniformly.
In addition, although the manufacturing method of the composite_body | complex of this embodiment is not specifically limited, It is preferable that the above-mentioned process a, process b, and process c are included at least. Another process may enter between each process.
The composite 12 may be further coated with another metal or metal oxide to improve stability. The metal or metal oxide used for coating is not particularly limited. Examples of such metals or metal oxides include gold, silver, copper, aluminum, iron, platinum, zinc, palladium, ruthenium, iridium, rhodium, osmium, chromium, cobalt, nickel, manganese, vanadium, molybdenum, and gallium. And metals such as aluminum, metal salts, metal complexes and alloys thereof, or oxides and double oxides.

Although not particularly limited, when the resin molded body 1 is produced, the composite may be fractionated and concentrated as necessary from the composite dispersion. When the amount of the solvent is excessive, the concentration of the resin composition to be described later becomes low. For example, when forming the resin molded body into a sheet, energy is required to remove the solvent, and productivity is poor. By concentrating the composite, the solid content concentration of the resin composition is increased, and the amount of solvent in manufacturing the molded body is reduced. Therefore, the molded body can be efficiently manufactured. Examples of the fractionation / concentration method include centrifugation, gel filtration column, gel electrophoresis, lyophilization, ultrafiltration, precipitation, and the like. A plurality of fractionation and concentration methods may be combined. Hereinafter, the complex dispersion and the complex recovered by fractionation or concentration are referred to as a complex-containing material.
When concentrating micronized cellulose by centrifugation, it is necessary to concentrate by ultracentrifuge. However, when a plate-like silver / micronized cellulose composite (composite) is composited with a resin, since a metal with high density is bound, the sedimentation coefficient is increased, and compared with the case of a micronized cellulose dispersion alone, It is possible to concentrate very efficiently. For this reason, it is possible to reduce the ratio of the solvent when compounding with the resin, and it becomes possible to obtain a molded body efficiently.

[Synthetic resin]
The resin molded body 1 according to the present embodiment includes a synthetic resin 11 having at least one of an aqueous dispersion component and an aqueous emulsion component. Here, the aqueous dispersion and the aqueous emulsion are sometimes referred to as an aqueous dispersion and an aqueous emulsion, respectively, and any aqueous resin dispersed in an aqueous dispersion medium containing water is included in this embodiment. In addition, the expression synthetic resin 11 is used as a general term for aqueous dispersions and aqueous emulsion resins.
These aqueous dispersions and aqueous emulsions are those in which water is used as a main dispersion medium and a polymer is dispersed in a particle size of submicron to several microns. By volatilizing these dispersion media, the polymers are deformed and fused to form a continuous structure.

Aqueous dispersions and aqueous emulsions have the advantage that the degree of freedom in design is higher than that of water-soluble monomers and water-soluble oligomers as a resin, and materials can be selected according to the intended performance and function. Furthermore, the addition of an emulsifier and the introduction of a hydrophilic group into the resin imparts dispersion stability in the dispersion medium, but the synthetic resin 11 itself is hydrophobic and has high water resistance and moisture resistance. . Therefore, it is difficult to be influenced by the external humidity environment, and when the moisture content of the resin molded body 1 is changed, there is no significant deformation, and the structure as the resin molded body 1 can be maintained.
In addition, the aqueous dispersion and aqueous emulsion have a high degree of polymerization of the synthetic resin 11, but the synthetic resin 11 forms individual fine particles, so that the viscosity as a coating liquid is low. Therefore, even if the composite-containing material that is a constituent material of the present embodiment has a high viscosity, good mixing properties can be obtained.

  As described above, the aqueous dispersion and the aqueous emulsion in the present embodiment are dispersed as resin particles in an aqueous dispersion medium containing at least water. And the resin particle has distribution to some extent in particle diameter. At the time of coating and molding of the resin molded body 1 before molding, the interaction with the composite-containing material to be mixed and other components, the melting temperature, etc. affect the agglomeration form of the resin particles when deforming and fusing. For this reason, the particle diameter of the synthetic resin 11 does not correspond to an element that uniquely determines the size of the hydrophobic region made of the synthetic resin 11 in the structure of the resin molded body 1. However, when the particle diameter of the synthetic resin 11 is too small, the specific surface area is large, so that the interaction with the refined cellulose 22 and other components in the composite 12 mixed by the electrical action on the surface of the resin particles is large. This makes it easier to cause fusion between the synthetic resins 11. As a result, the size of the hydrophobic region made of the synthetic resin 11 is reduced. In this case, since there are a large number of interfaces between the hydrophobic region and the hydrophilic region, scattering by the light interface occurs regardless of the water content, and the haze of the resin molded body 1 increases. On the other hand, when the particle diameter of the synthetic resin 11 is too large, it becomes difficult to uniformly disperse the synthetic resin 11 and the other components including the refined cellulose 22 in the composite body 12 when the resin molded body 1 is molded. . Therefore, the particle size of the aqueous dispersion or aqueous emulsion is preferably in the range of 0.01 μm or more and 10 μm or less, which is an appropriate size for the purpose of this embodiment.

Aqueous dispersions and aqueous emulsions are roughly classified into anionic, cationic and nonionic properties depending on ionicity. In the present embodiment, any use is not limited. However, when the micronized cellulose 22 of the composite 12 to be mixed is anionic, mixing the cationic synthetic resin 11 may inhibit the charge. Or nonionic properties are preferred.
As the synthetic resin 11 composed of an aqueous dispersion or an aqueous emulsion, for example, vinyl acetate, urethane, acrylic, styrene, phenol, amino, amide, polyester, ethylene, polyvinyl alcohol are used. . These may be used alone, or may be copolymerized or used in combination of two or more. A reactive synthetic resin 11 may also be used. In that case, for example, a curing agent, a curing catalyst, a photopolymerization initiator, a chain transfer agent, and the like can be used in combination. Here, in order to improve the brittleness caused by the phase separation between the synthetic resin 11 and the composite body 12 constituting the resin molded body 1, the synthetic resin 11 preferably has flexibility, and a urethane type is more preferable. preferable. In the urethane system, a polyester system, a polyether system, a polycarbonate system, and the like have been developed depending on the kind of polyol constituting the urethane structure, and any of them can be used.

(Method for producing resin molded body 1)
Hereinafter, the manufacturing method of the resin molding 1 which concerns on this embodiment is demonstrated.
The resin molded body 1 in the present embodiment is not particularly limited, but includes at least a synthetic resin having at least one of an aqueous dispersion component and an aqueous emulsion component, and a plate-like metal / micronized cellulose composite (composite), The composite is a composite of flat metal fine particles and finely divided cellulose, in which flat metal fine particles and at least one or more refined cellulose are composited, and at least for each refined cellulose. It can be formed by a resin composition that is partly (partially) or wholly incorporated into the plate-like metal fine particles, and the rest is composited so as to be exposed on the surface of the plate-like metal fine particles.

  A resin composition can be obtained by mixing a synthetic resin 11 composed of an aqueous dispersion or an aqueous emulsion and a composite-containing material. At this time, the mixability with the synthetic resin 11 can be improved by dispersing the composite-containing material in advance with water or an aqueous solvent. For the purpose of not reducing the solid content concentration of the coating liquid in wet coating, the composite-containing material may be subjected to a dispersion treatment in the synthetic resin 11 as it is. Cellulose fibers may be refined in a dispersion medium of aqueous dispersion or resin particles of an aqueous emulsion to obtain a refined cellulose dispersion, and the composite may be dispersed in a dispersion medium of resin particles of an aqueous dispersion or aqueous emulsion. Even if it is prepared, when there is no problem in dispersibility and the subsequent formation of the resin molded body 1, various known dispersion treatments and composite production are possible.

  Examples of the dispersion treatment include homomixer treatment, mixer treatment with a rotary blade, high pressure homogenizer treatment, ultrahigh pressure homogenizer treatment, ultrasonic homogenizer treatment, nanogenizer treatment, disc type refiner treatment, conical type refiner treatment, double disc type refiner treatment, There are grinder processing, ball mill processing, kneading processing with a biaxial kneader, underwater facing processing, and the like. Among these, the mixer treatment with a rotary blade, the high-pressure homogenizer treatment, the ultra-high pressure homogenizer treatment, and the ultrasonic homogenizer treatment are preferable from the viewpoint of miniaturization efficiency. Of these processes, two or more processing methods can be combined and distributed.

  Here, the solid content of the composite-containing material mixed with the synthetic resin 11 is preferably 1% by mass or more and 50% by mass or less, and more preferably 10% by mass or more and 30% by mass or less. The solid content of the composite-containing material is the total amount of fine cellulose and metal fine particles. When the solid content of the composite is less than 1% by mass, swelling due to water content of the composite-containing material in the resin molded body 1 is difficult to occur, and as a result, the cloudiness and opacity may decrease. On the other hand, when the amount exceeds 50% by mass, the hydrophobic region due to the synthetic resin 11 is dispersed in the matrix of the refined cellulose 21 in the composite 12, and it becomes difficult to control the moisture content of the resin molded body 1 itself. Since the interface of the region is relatively reduced, the resulting opaque opacity may be reduced.

The solid content of the metal contained in the composite-containing material is preferably 0.01% by mass or more and 50.00% by mass or less, and more preferably 0.05% by mass or more and 10% by mass or less. If the solid content is within this range, the optical properties of the composite are sufficiently exhibited.
The resin composition includes at least water as a solvent, but may further include a known solvent other than water. From the viewpoint of mixing with the composite 12, it is preferable to use a hydrophilic solvent as the solvent. Although it does not specifically limit as a hydrophilic solvent, Alcohols, such as methanol, ethanol, isopropanol, are preferable. Of these solvents, ethanol is preferred.

Although there is no restriction | limiting in particular as a method of forming the resin molding 1 using the resin composition which mixed the synthetic resin 11 and composite containing material prepared in this way, The resin composition has fluidity | liquidity. Therefore, the resin molding 1 can be obtained by wet-coating and curing on a support such as a resin substrate or a glass substrate.
As a coating method, a known method can be used. Specifically, bar coating, dip coating, spin coating, flow coating, spray coating, roll coating, gravure roll coating, air doctor coating, blade coating, wire doctor coating, knife coating Methods, reverse coating method, transfer roll coating method, micro gravure coating method, kiss coating method, cast coating method, slot orifice coating method, calendar coating method, die coating method and the like can be used.

For the purpose of improving the wettability and adhesion of the base material to which the resin composition obtained by mixing the synthetic resin 11 and the composite-containing material is applied, the base material may be pretreated. The pretreatment method is not particularly limited. For example, an anchor layer may be formed in advance, or corona treatment, plasma treatment, flame treatment, or the like may be performed.
The resin molded body 1 can be formed by drying the resin composition coated on the support, that is, by removing excess dispersion medium in the system. Further, the resin molded body 1 may be additionally heated after the production of the resin molded body 1 for the purpose of improving the reaction of the resin and improving other characteristics. Moreover, when using a photoreactive material, you may irradiate the resin molding 1 with the light of the wavelength which advances reaction.

The resin molded body 1 formed in this way is shown in FIG.
The thickness T of the resin molded body 1 obtained in this embodiment is preferably in the range of 1 μm to 500 μm, more preferably in the range of 10 μm to 200 μm, and particularly preferably in the range of 20 μm to 100 μm. When the thickness T is less than 1 μm, the strength of the resin molded body 1 becomes extremely weak and unsuitable for production. On the other hand, if the thickness exceeds 500 μm, the drying speed is very long, and the productivity is extremely lowered, and excessive moisture remains in the resin molded body 1.

By using a composite-containing material, it becomes possible to obtain a resin composition at a high concentration more efficiently than mixing a finely divided cellulose alone with a resin to form a composite, and a resin molded product with a thick film efficiently. Can be obtained.
As the support for forming the resin molded body 1, for the purpose of improving the visibility, a layer having a metallic luster or a layer having various colors may be used. These layers having metallic luster and various colors can be formed in advance on the side of the support on which the resin molded body 1 is formed, or if the support is transparent, the support It is also possible to form the body on the surface opposite to the side on which the resin molded body 1 is formed.

  As another support for forming the resin molded body 1, a laminate in which a moisture retention layer having moisture retention properties is laminated may be used for controlling the water absorption speed and transparency. The moisturizing agent constituting the moisturizing layer is not particularly limited, and examples thereof include cellulose, cellulose derivatives, chitin, chitosan derivatives, starch, hyaluronic acid, alginic acid, gelatin, kaolin, dextrin, glycerin, polyglycerin, D-sorbitol, PVA and the like. In particular, glycerin and sorbitol are preferable. Moreover, only one type of moisturizing agent used for the moisturizing layer may be used, and two or more types may be used in combination.

(Various additive materials)
In the present embodiment, a thermosetting resin may be further added to the resin molded body 1. When the thermosetting resin is used, the step of removing the dispersion medium such as water contained in the coated resin composition and the molding step of fusing the particles of the synthetic resin 11 can proceed simultaneously. .
In addition, since the resin can be selectively cured by irradiating the resin molding 1 with active energy rays such as ultraviolet rays and electron beams, a photo-curable resin may be further added. . In addition, you may insert a heating process for the purpose of removing a solvent or improving the reactivity in the process of hardening reaction.

By adding these thermosetting resins and photocurable resins to the resin molded body 1, the binding property between the hydrophobic regions of the synthetic resin 11 made of an aqueous dispersion or an aqueous emulsion can be improved, Adjustment suitable for various purposes, such as controlling the water absorption rate of the refined cellulose 22 in the mechanical properties and the composite-containing material, can be made.
Moreover, in order to form a crosslinked structure for the purpose of improving water resistance and abrasion resistance, the resin molded body 1 may contain various crosslinking agents. Although it does not limit as a crosslinking agent which forms a crosslinked structure by heating, For example, an oxazoline, a divinyl sulfone, a carbodiimide, a dihydrazine, a dihydrazide, an epichlorohydrin, a glyoxal, an organic titanium compound, an organic zirconium compound etc. can be used. Moreover, it is also possible to mix and use two or more of them. Among these, carbodiimide is preferable because it can efficiently form a crosslinked structure without applying large energy.

Furthermore, when the resin molding 1 is irradiated with active energy rays such as ultraviolet rays and electron beams to cure the resin, a photocrosslinking agent or a photopolymerization initiator may be used. These types are not particularly limited, and examples include acetophenone photopolymerization initiators, benzoin photopolymerization initiators, benzophenone photopolymerization initiators, thioxanthone photopolymerization initiators, and thioxanthone photopolymerization initiators. it can.
In addition, in the range where aggregation or precipitation does not occur in the resin composition obtained by mixing the synthetic resin 11 and the composite-containing material, a function to be added for the purpose of adjusting the viscosity, adjusting the drying speed, improving the affinity with different materials, etc. Depending on the situation, various organic solvents including water can be mixed.

At this time, in order to relieve shock caused by mixing different solvents, for example, the addition rate, pH adjustment, stirring method, temperature, and the like can be appropriately selected.
Moreover, the resin molding 1 may contain a metal etc. as another additive. Examples of the metal contained in the resin molding 1 include platinum group elements such as gold, silver, platinum, palladium, ruthenium, iridium, rhodium, and osmium, as well as iron, lead, copper, chromium, cobalt, nickel, manganese, and vanadium. Further, metals such as molybdenum, gallium, and aluminum, alloys thereof, oxides, double oxides, carbides, and the like can be used.
The resin molded body 1 can be mixed with known additives for the purpose of improving moldability, suppressing deterioration, and improving the dispersibility of the optical material. For example, a heat stabilizer, a stabilizing aid, a plasticizer, an antioxidant, a light stabilizer, a flame retardant, a lubricant, and an antistatic agent may be included.

  In the range where aggregation and precipitation do not occur, various additives including water-soluble polysaccharides and various resins may be included for the purpose of increasing the charge repulsion in the resin composition and controlling the viscosity of the dispersion. Good. For example, chemically modified cellulose, carrageenan, xanthan gum, guar gum, gum arabic, sodium alginate, agar, solubilized starch, glycerin, sorbitol, antifoaming agent, water-soluble polymer, synthetic polymer and the like can be included. Alternatively, various solvents may be included for imparting functionality such as coatability and wettability. For example, alcohols, cell solves, glycols and the like can be included. Furthermore, various dyes, pigments, organic fillers, inorganic fillers and the like may be included for the purpose of imparting design properties. Further, for the purpose of improving the reactivity, the pH can be adjusted by adding an acid or an alkali.

(Effect of this embodiment)
Since the resin molded body 1 according to the present embodiment includes the composite 12 having absorption in a specific wavelength region, the resin molded body 1 preferably has a minimum wavelength (λmax) in which the transmittance is minimum in a wavelength region of 400 nm to 2500 nm. . The specific wavelength can be absorbed or reflected by the effect of the composite 12.
The method for measuring the transmission spectrum is not particularly limited, but can be measured by the following method. The reference was measured in the sky, and the light transmittance of the resin molding was measured with a spectrophotometer UV-3600 (manufactured by Shimadzu Corporation) from a wavelength of 220 nm to 2500 nm. The wavelength at which the light transmittance is minimized from the obtained light transmittance is defined as λmax (nm) of the resin molded body.

Moreover, the resin molding 1 which is this embodiment improves the strength of the resin molding by the effect of the composite 12. It is preferable that the maximum strength of the resin molded body is 40 N / mm ² or more and the elongation at break is 4% or more.
The maximum strength and elongation at break are not particularly limited, but can be measured by, for example, the following method. The resin molded body 1 is cut into a strip with a width of 15 mm, and a small desktop tester EZ-LX (manufactured by Shimadzu Corporation) is used, with a load cell of 1.000 N and a tensile speed of 5 mm / min, with an interval of 50 mm between the evaluation parts. Thus, the tensile strength (N / mm ² ) and elongation at break (%) can be measured by detecting the elongation and strength in the long side direction while chucking both ends. The resin molded body is conditioned in a constant temperature and humidity chamber at 23 ° C. and 47 to 50% RH one day or more before measurement, and measurement is also performed in the same environment.

Furthermore, the resin molding 1 which is this embodiment has high dimensional stability, and a linear expansion coefficient becomes low. The linear expansion coefficient of the resin molded body of the present embodiment is preferably 100 × 10 ⁻⁵ / K or less, more preferably 10 × 10 ⁻⁵ / K or less. When the linear expansion coefficient is within this range, the dimensional stability becomes high.
The linear expansion coefficient is not particularly limited, but can be measured by the following method. The resin molded body was cut into a strip of 15 mm in length and 4 mm in width, and the elongation in the long side when heated at 5 ° C./min from 15 to 180 ° C. while chucking both ends with a tension of 50 mN It measures using apparatus TMA / SS-6000 (made by Seiko Instruments), and calculates a linear expansion coefficient from the sample elongation from 140 degreeC to 160 degreeC more than Tg.

About control of the optical characteristic of the resin molding 1 by this embodiment, it is possible to use the moisture content of the resin molding 1 as a parameter | index. The water content of the resin molded body 1 can be changed, for example, by immersing the resin molded body 1 in a dry state in water. When the haze of the surface when the moisture content of the resin molded body 1 reaches saturation when sufficiently immersed in water is HZ ₁ , the moisture content is dehumidified and the moisture content shows a moisture content in an equilibrium state with normal temperature and normal humidity. when the haze was HZ _2, it is preferable to satisfy HZ 1 -HZ ₂ ≧ 15 (%) of. In order to ensure visibility, it is preferable to have a difference of 15% or more as haze due to a change in moisture content, and it is more preferable to have a difference of 30% or more. Furthermore, the haze of the resin molded body 1 can be generally used as the resin molded body 1 having transparency at normal temperature and humidity by setting HZ ₂ ≦ 5 (%). In other words, when the haze when the moisture content of the resin molded body 1 is 25% or more is HZ ₁ and the haze when the moisture content of the resin molded body 1 is 8% or less is HZ ₂ , HZ ₁ − It is preferable to satisfy HZ ₂ ≧ 15 (%).

Here, “the state where the resin molded body 1 is dried” refers to a state where the moisture content of the resin molded body 1 is 8% or less. Or the state which reached the equilibrium in the humidity environment where the moisture content of the resin molding 1 is lower than normal temperature normal humidity. The above-mentioned “room temperature and humidity” means “23 ° C., 50% RH”, and “room temperature and humidity” means “23 ° C., 50% RH environment”.
The resin molded body of the present embodiment can repeatedly write and erase various types of visible information using reversible changes in transparency due to changes in moisture content.
More specifically, with such a configuration, the transparency is reversibly changed from a transparent state to a cloudy and opaque state only by changing the moisture content.

  The difference between the transparent state and the cloudy opaque state is estimated as follows. That is, in the transparent state (that is, when the resin molding 1 is in a dry state), the hydrophobic region by the synthetic resin 11 containing at least one of the aqueous dispersion component and the aqueous emulsion component, and the refinement of the composite The hydrophilic region of cellulose 22 is distributed in phase separation. Here, since the refractive index of the synthetic resin 4 and the refined cellulose 22 is close, and the minor axis diameter of the fiber of the refined cellulose 22 is smaller than the wavelength of visible light, the light incident from one side is not scattered and is opposite. Transparent to the side, so it looks transparent. On the other hand, in the case of a cloudy opaque state (that is, when the resin molded body 1 is in a wet state), the interface between the particles of the synthetic resin 11 and the refined cellulose 22 is caused by swelling of the refined cellulose 22 of the composite. The difference in refractive index is caused, and it is refracted and scattered many times at the interface, so that it appears cloudy. The swelling behavior of the refined cellulose 22 is controlled only by the amount of water taken in by the refined cellulose 22, that is, the moisture content of the refined cellulose 22. Therefore, the transparency can be controlled by controlling this moisture content. It becomes possible.

[Usage method of resin molding]
Although the resin molding of this embodiment is not specifically limited, For example, it can apply to an optical filter, a thermal insulation film, an antibacterial film, personal care goods, cosmetics, a medical material, etc. Furthermore, by using a reversible change in transparency due to a change in moisture content, it is possible to easily and inexpensively provide a labeling material that can be repeatedly written and erased with visible information.

EXAMPLES Hereinafter, although an Example demonstrates this invention further more concretely, this invention is not limited to a following example.
<Example 1>
(Production of refined cellulose)
(Reagents and materials)
・ Cellulose: Bleached kraft pulp (Fletcher Challenge Canada "MACHENZIE")
・ TEMPO: Commercial product (Tokyo Chemical Industry Co., Ltd., 98%)
Sodium hypochlorite: Commercial product (Wako Pure Chemical Industries, CL: 5%)
・ Sodium bromide: Commercial product (Wako Pure Chemical Industries, Ltd.)

(Oxidation process)
70 g of softwood kraft pulp was suspended in 3500 g of distilled water to prepare a suspension.
To this suspension was added a solution prepared by dissolving 0.7 g of TEMPO and 7 g of sodium bromide in 350 g of distilled water, and cooled to 20 ° C.
To this solution, 450 g of an aqueous sodium hypochlorite solution having a concentration of 2 mol / L and a density of 1.15 g / mL was added dropwise to start an oxidation reaction. The temperature in the system during the reaction was always kept at 40 ° C. Further, the pH in the system was lowered during the reaction, but the pH was kept at 10 by successively adding a 0.5N aqueous sodium hydroxide solution.
When sodium hydroxide reached 3.0 mmol / g based on the mass of cellulose, an excessive amount of ethanol was added to stop the reaction.
Then, after filtering the mixture after reaction with a glass filter, the cellulose oxide was obtained by repeating the water washing and filtration by sufficient quantity of water.

(Miniaturization process)
1 g of oxidized cellulose obtained by TEMPO oxidation was dispersed in 99 g of distilled water.
And the refinement | purification process was performed to the dispersion liquid containing an oxidized cellulose using the high pressure homogenizer, and the refinement | purification cellulose aqueous dispersion whose content of refinement | purification cellulose is 1 mass% was obtained.

(Manufacture of complex)
Subsequently, 250 mg of silver nitrate was dissolved in 50 mL of distilled water to prepare an aqueous silver nitrate solution.
Sodium borohydride (250 mg) was dissolved in distilled water (50 mL) to prepare a sodium borohydride aqueous solution.
0.2 L of the above-mentioned fine cellulose aqueous dispersion is put in a container, and while stirring with a stirring blade, 2.4 g of an aqueous silver nitrate solution is added at room temperature (25 ° C.) to prepare a dispersion containing fine cellulose and silver nitrate. did. Subsequently, a sodium borohydride aqueous solution was added to the dispersion containing finely divided cellulose and silver nitrate and reacted to produce a composite dispersion. The complex in the obtained complex dispersion is referred to as complex A.

(Recovery of complex-containing materials)
The complex A dispersion is diluted in a 200 mL centrifuge tube, centrifuged at 10,000 × g (g is gravitational acceleration), the precipitated complex is recovered, and the solid content concentration is 10% by mass. A complex A-containing material was obtained.

<Preparation of Resin Composition and Resin Molded Body 1>
(1) Preparation of Resin Composition Synthetic resin I (polyurethane dispersion hydran HW171, manufactured by DIC) and the composite A-containing material prepared by the above-described procedure have a solid content mass ratio of 70:30 in this order. Were mixed overnight with a stirrer to prepare a resin composition of synthetic resin I and composite A. In addition, the solid content rate of the silver in a resin composition was 0.05 mass%.
(2) Production of Resin Molded Body 1 The prepared resin composition was applied to a PET film (Lumirror T60-75 μm: Toray) with an applicator, dried in an oven at 120 ° C. for 10 minutes, and then peeled off. Thus, a resin molded body 1 having a thickness of 50 μm was produced.

<Example 2>
A resin molded body 1 was produced under the same conditions as in Example 1 except that the film thickness of the resin molded body was changed to 20 μm in Example 1.
<Example 3>
In Example 1, resin molded body 1 was produced under the same conditions as in Example 1 except that the thickness of the resin molded body was changed to 100 μm.
<Example 4>
The synthetic resin I and the complex A-containing material were prepared so that the solid mass ratio was 90:10 in this order. Otherwise, the resin molded body 1 was produced under the same conditions as in Example 1.

<Example 5>
The synthetic resin I and the composite A-containing material were prepared so that the solid mass ratio was 50:50 in this order. Otherwise, the resin molded body 1 was produced under the same conditions as in Example 1.
<Example 6>
Synthetic resin I and synthetic resin II (polyurethane dispersion Evaphanol HA560, manufactured by Nikka Chemical Co., Ltd.) and the composite A-containing material were prepared in this order in a solid content mass ratio of 40:40:20. Otherwise, the resin molded body 1 was produced under the same conditions as in Example 1.

<Example 7>
Synthetic Resin I, Synthetic Resin III (Polyurethane Dispersion Hydran UV-100S, manufactured by DIC), Photopolymerization Initiator I (Irgacure 2959, manufactured by BASF), and Complex A-containing material in this order in terms of solid content mass ratio 55:24 1:20, and the resin composition was applied to a PET film (Lumirror T60-75 μm, manufactured by Toray Industries, Inc.) with an applicator and dried in an oven at 120 ° C. for 10 minutes. UV cured at / cm ² . Otherwise, the resin molded body 1 was produced under the same conditions as in Example 1.
<Example 8>
In the production of the composite, 4.8 g of an aqueous silver nitrate solution was added to prepare a composite B, and the same amount of the composite B-containing material was used instead of the composite A-containing material. Otherwise, the resin molded body 1 was produced under the same conditions as in Example 1.

<Comparative Example 1>
In the production of the composition and the resin molded body 1, a resin molded body 1 was produced under the same conditions as in Example 1 except that the same mass of water was used instead of the composite A-containing material.
<Comparative Example 2>
A resin molded body 1 was produced under the same conditions as in Example 6 except that the same mass of water was used instead of the composite A-containing material.
<Comparative Example 3>
In the production of the composite, the resin molded body 1 was formed under the same conditions as in Example 1 except that gelatin, which is a water-soluble polymer having the same mass, was used instead of fine cellulose, and a product C as silver fine particles was obtained. Produced. In Comparative Example 3, silver fine particles are merely generated in an aqueous gelatin solution, and gelatin and silver do not form a composite.

<Evaluation method>
About Examples 1-8 and Comparative Examples 1-3, the evaluation result of refined cellulose is shown in Table 1, FIG. 8, FIG. 9, the evaluation result of the composite is shown in Table 2, and the STEM of the composite A and the composite B The images are shown in FIGS. 10 and 11, the production conditions of the resin molded body 1 are shown in Table 3 below, and the evaluation results of the resin molded body 1 are shown in Table 4.
About the oxidized cellulose and refined cellulose obtained in Example 1, the measurement and calculation of the amount of carboxy groups, crystallinity, number average axis diameter of major axis, light transmittance and rheology were performed as follows. The evaluation results of the obtained refined cellulose are shown in Table 1, FIG. 8, and FIG.

[Measurement of carboxy group content]
For the oxidized cellulose before the dispersion treatment, the amount of carboxy group was calculated by the following method.
0.2 g of dry weight equivalent of oxidized cellulose was taken in a beaker, and 80 mL of ion-exchanged water was added.
Thereto was added 5 mL of 0.01 mol / L sodium chloride aqueous solution, and 0.1 mol / L hydrochloric acid was added while stirring to adjust the whole to pH 2.8.
Then, using an automatic titration apparatus (trade name: AUT-701, manufactured by Toa DKK Co., Ltd.), a 0.1 mol / L sodium hydroxide aqueous solution was injected at 0.05 mL / 30 seconds, and the conductivity every 30 seconds was measured. The pH value was measured and the measurement was continued until pH 11.
From the obtained conductivity curve, the titration amount of sodium hydroxide was determined, and the content of carboxy group was calculated.

[Calculation of crystallinity]
The crystallinity of TEMPO oxidized cellulose was calculated.
For TEMPO-oxidized cellulose, using a sample horizontal multi-purpose X-ray diffractometer (trade name: Ultimate III, manufactured by Rigaku), X-ray output: (40 kv, 40 mA) under the condition of 5 ° ≦ 2θ ≦ 35 ° The line diffraction pattern was measured. Since the obtained X-ray diffraction pattern is derived from the cellulose I-type crystal structure, the crystallinity of TEMPO-oxidized cellulose was calculated by the following method using the following formula (2).
Crystallinity (%) = [(I22.6-I18.5) /I22.6] × 100 (2)
However, I22.6 is the diffraction intensity of the lattice plane (002 plane) (diffraction angle 2θ = 22.6 °) in X-ray diffraction, and I18.5 is the diffraction of the amorphous portion (diffraction angle 2θ = 18.5 °). Indicates strength.

[Calculation of number average shaft diameter of major axis of fine cellulose]
The number average axial diameter of the major axis of the refined cellulose was calculated using an atomic force microscope.
First, after diluting the micronized cellulose aqueous dispersion to 0.001%, it was cast on a mica plate by 20 μL and air-dried.
After drying, the shape of the refined cellulose was observed in the DFM mode using an atomic force microscope (trade name: AFM5400L, manufactured by Hitachi High-Technologies Corporation).
The number average axial diameter of the major axes of the fine cellulose was determined by measuring the major axis diameter (maximum diameter) of 100 fibers from an image observed with an atomic force microscope, and obtaining the average value.
[Measurement of light transmittance of micronized cellulose dispersion]
The light transmittance was measured for the finely divided cellulose aqueous dispersion.
One of the quartz sample cells is filled with water as a reference, and the other is filled with a finely divided cellulose aqueous dispersion so that bubbles are not mixed. It was measured with a meter (trade name: NRS-1000, manufactured by JASCO Corporation).

[Rheological measurement]
The rheology of a dispersion of 0.5% by mass of fine cellulose was measured with a rheometer (trade name: AR2000ex, manufactured by TA Instruments Inc.) using a cone plate with an inclination angle of 1 °.
The temperature of the measurement part was adjusted to 25 ° C., and the shear viscosity was continuously measured at a shear rate of 0.01 s ⁻¹ to 1000 s ⁻¹ . Table 1 shows the shear viscosity when the shear rate is 1 s ⁻¹ and 100 s ⁻¹ .

[Λmax measurement of complex]
The light transmittance was measured for the composite-containing materials of Examples 1 to 8 and the product C of Comparative Example 3.
A sample or reference was placed in a quartz sample cell, and the light transmittance from a wavelength of 220 nm to 1300 nm at an optical path length of 1 cm was measured with a spectrophotometer UV-3600 (manufactured by Shimadzu Corporation). The complex-containing material was appropriately diluted with water and measured in a quartz cell so that bubbles were not mixed. From the obtained light transmittance, the wavelength at which the light transmittance was minimized was defined as λmax (nm) of the dispersion. The results are shown in Table 2.

[Observation of product]
A dispersion containing the composites of Examples 1 to 8 and Comparative Examples 1 and 2 was cast on a copper grid with a supporting film and air-dried, and then scanned with an electron microscope (trade name: S-4800, Hitachi High-Technologies Corporation). The product A of Example 1-8, the composite B, and the product C of the comparative example 3 were observed in STEM mode.

[Calculation of average particle size]
The composite-containing materials of Examples 1 to 8 and the dispersion of the product C of Comparative Example 3 were cast on a copper grid with a support film for transmission electron microscope observation and air-dried, and then observed with a scanning transmission electron microscope. . The equivalent-circle particle diameter is calculated as the particle diameter in the plane direction from the area when the flat metal particles in the scanning transmission electron microscope image are approximated by a circle. The average value was obtained by measuring 100 particles.

[Calculation method of average aspect ratio]
The average aspect ratio of the composite-containing materials of Examples 1 to 8 and the product C of Comparative Example 3 was a value obtained by dividing the average particle diameter obtained as described above by the average thickness. The dispersion containing the sample is cast on a polyethylene terephthalate (PET) film, air-dried, and fixed with an embedding resin, cut in the cross-sectional direction with a microtome, and observed with a transmission electron microscope. A transmission electron microscope image of the observed flat metal fine particles was obtained. The thickness of the flat metal fine particles in the transmission electron microscope was calculated as the thickness perpendicular to the plane direction, and the average value was obtained by measuring 100 particles.
As the average value of the diameter d (equivalent circle diameter) with respect to the average value of the thickness of the flat metal fine particles and the aspect ratio of the flat metal fine particles 21 (average value of d / average value of h) obtained as described above. Calculated.

[Tensile properties of resin molding 1]
The obtained resin molded body 1 was cut into a strip shape having a width of 15 mm, and a small tabletop testing machine EZ-LX (manufactured by Shimadzu Corporation) was used, with a load cell of 1.000 N and a tensile speed of 5 mm / min. The elongation and strength in the long side direction were detected while chucking both ends at intervals, and the maximum strength (N / mm ² ) and elongation at break (%) were measured. The resin molded body was conditioned in a constant temperature and humidity chamber at 23 ° C. and 47 to 50% RH one day or more before measurement, and the measurement was performed in the same environment.

[Linear expansion coefficient of molded resin 1]
The resin molded body 1 is cut into a 15 mm long, 4 mm wide strip, and stretched in the long side direction when heated at 5 ° C./min from 15 to 180 ° C. while chucking both ends with a tension of 50 mN. The linear expansion coefficient was calculated from the linear expansion coefficient from 20 ° C. to 40 ° C. and the sample elongation from 140 ° C. to 160 ° C., which is equal to or higher than Tg, using a mechanical apparatus TMA / SS-6000 (manufactured by Seiko Instruments).

[Measurement of light transmittance of resin molded body 1]
The reference was measured in the sky, and the light transmittance of the resin molding 1 was measured with a spectrophotometer UV-3600 (manufactured by Shimadzu Corporation) from a wavelength of 220 nm to 2500 nm. From the obtained light transmittance, the wavelength at which the light transmittance was minimized was defined as λmax (nm) of the resin molded body 1.

[Haze of resin molding 1]
About the obtained resin molding 1, after immersing in water for 1 minute, the surface water | moisture content was wiped off, and Haze Mater NDH200 (made by Nippon Denshoku) was used about the surface on the opposite side to PET at the time of formation of the resin molding 1 immediately after. The haze was measured. The value of this time was the HZ _1. Furthermore, after the sample immersed in water was dried in an oven at 60 ° C. for 30 minutes and then conditioned for 2 days in a thermostatic chamber at 23 ° C. and 50% RH, the haze was measured in the same manner. The value of this time was the HZ _2. At this time, when satisfying the following formulas (1) and (2), “◯” was set, and when not satisfying, “×” was set.
HZ ₁ −HZ ₂ ≧ 15 (%) (1)
HZ ₂ ≦ 5 (%) (2)

[Visibility]
With respect to the resin molded body 1 under the same conditions as those measured for haze HZ ₂ , writing was performed on the resin molded body 1 using a writing instrument capable of holding moisture, and a sensory evaluation was performed as to whether the resin molded body 1 could be visually confirmed. . Note that “◎” indicates that the visibility was extremely high, “○” indicates that the visibility was high, “△” indicates that the visibility was high enough to be used, and “×” indicates that the visibility was low. As evaluated.
[Repeated durability]
The visibility when the resin molded body 1 was dipped in water for 1 minute and dried in a 60 ° C. oven for 30 minutes 100 times was visually evaluated. As in the case of the visibility evaluation described above, “◎” indicates that the visibility is extremely high, “○” indicates that the visibility is high, and “△” indicates that the visibility is high enough to be used. Those with low visibility were evaluated as “x”.

FIG. 8 is a graph showing the results of measuring the transmittance of the finely divided cellulose aqueous dispersion of Example 1. FIG. 9 is a graph showing the evaluation results of the viscosity characteristics of the finely divided cellulose aqueous dispersion of Example 1.
From the results of Table 1, FIG. 8, and FIG. 9, it was found that in Example 1, high crystallinity, high transmittance in the visible light region, and low viscosity refined cellulose could be produced.
Table 2 shows λmax, average particle diameter, average thickness, and average aspect ratio of the composite A, the composite B, and the product C prepared in Comparative Example 3 prepared in Examples 1 to 8.

A resin molded body 1 was produced under the conditions shown in Table 3. Table 4 shows the results of producing the resin molded body 1 under the conditions described in Table 3 and evaluating the mechanical characteristics, linear expansion coefficient, minimum value of transmittance (λmax), haze, and visibility.
In Example 1 to Example 8, the mechanical properties are controlled by the composition, and high dimensional stability is exhibited. From the haze characteristics and visibility, reversible transparency change due to change in moisture content is utilized. It becomes possible to repeatedly write and erase various types of information that can be visually checked. Furthermore, the optical characteristic which shields the specific wavelength range by a composite_body | complex is shown. On the other hand, in Comparative Examples 1 to 3, the mechanical properties were not good, and the haze properties and visibility were not good.

  The resin molded body 1 of the present embodiment can sufficiently exhibit the optical characteristics of the metal / micronized cellulose composite, and the composite has good mechanical characteristics and dimensional stability of the resin molded body and has antibacterial properties. A resin molded body can be obtained. Furthermore, it is possible to easily and inexpensively manufacture a display material in which writing and erasing of each information can be repeated due to a change in moisture content.

DESCRIPTION OF SYMBOLS 1 ... Resin molding 11 ... Synthetic resin 12 ... Flat metal / micronized cellulose composite 21 ... Flat metal fine particle 22 ... Micronized cellulose 22a ... Micronized cellulose (metal) Part taken into the interior of the fine particles
22b: Fine cellulose (exposed portion on metal fine particle surface)
23 ... Front 24 ... Back 25 ... Side 26 ... PET layer 27 ... Embedded resin layer d ... Particle diameter h ... Particle thickness

Claims (14)

A synthetic resin having at least one of an aqueous dispersion component and an aqueous emulsion component, and a composite,
The composite is a composite of flat metal fine particles and finely divided cellulose, in which flat metal fine particles and at least one or more refined celluloses are composited, and at least for each refined cellulose. A resin molded body characterized in that a part or all of the resin is incorporated in the flat metal fine particles, and if there is a remainder, the remaining is exposed on the surface of the flat metal fine particles.   The solid content of the composite-containing material mixed with the synthetic resin is 1% by mass to 50% by mass, and the solid content of the metal is 0.01% by mass to 50.00% by mass. The resin molded product according to claim 1.   3. The resin molded body according to claim 1, wherein the resin molded body has a minimum wavelength at which the transmittance is minimum in a wavelength region of 400 nm to 2500 nm in the transmittance spectrum of the resin molded body. The resin molding according to any one of claims 1 to 3, wherein the resin molding has a breaking strength of 40 N / mm ² or more and a breaking elongation of 4% or more. 5. The resin molded body according to claim 1, wherein a linear expansion coefficient of the resin molded body is 100 × 10 ⁻⁵ / K or less.   The content of fine cellulose in the resin molded product is in a range of 5 parts by mass or more and 200 parts by mass or less with respect to 100 parts by mass of the synthetic resin. The resin molded product according to item 1. A synthetic resin having at least one of an aqueous dispersion component and an aqueous emulsion component, and at least hydrophilic fibers,
The haze of the resin molded body having a moisture content of 25% or more is HZ ₁ ;
If the water content was the haze of 8% or less of the resin molded body and HZ _2, wherein the preceding claims, characterized in that HZ ₁ and HZ ₂ satisfies the following formula (1) and (2) Item 7. The resin molded article according to any one of Items 6 above.
HZ ₁ −HZ ₂ ≧ 15 (%) (1)
HZ ₂ ≦ 5 (%) (2)   The resin molded product according to claim 7, wherein at least one of the aqueous dispersion component and the aqueous emulsion component is anionic or nonionic. The average value of the thickness h of the flat metal fine particles is in the range of 1 nm to 50 nm,
The average value of the particle diameter d is the range of 2 nm or more and 1000 nm or less, The resin molded object of any one of Claims 1-8 characterized by the above-mentioned.   The average value of the particle diameter d of the said flat metal fine particle is 2 times or more of the average value of the thickness h of the said flat metal fine particle, The any one of Claims 1-9 characterized by the above-mentioned. Resin molded body.   The said metal contains at least any one of gold | metal | money, silver, and copper, The resin molded object of any one of Claims 1-10 characterized by the above-mentioned.   The resin molded body according to any one of claims 1 to 11, wherein a thickness of the resin molded body is in a range of 1 µm to 500 µm.   A step of preparing a composite, a step of preparing a resin composition, and a step of preparing a resin molded body, wherein the resin molded body according to any one of claims 1 to 12 is wet-coated on a support. A method for producing a resin molded body, characterized by being formed by a process. A synthetic resin having at least one of an aqueous dispersion component and an aqueous emulsion component, and a composite,
The composite is a composite of flat metal fine particles and finely divided cellulose, in which flat metal fine particles and at least one or more refined celluloses are composited, and at least for each refined cellulose. A resin composition characterized in that a part or all of the resin composition is incorporated in the flat metal fine particles, and if there is a remainder, it is combined so that the remainder is exposed on the surface of the flat metal fine particles.