JP2009269197A - Method of molding nanocomposite resin, and method of manufacturing preform for optical member - Google Patents

Abstract

An object of the present invention is to provide a nanocomposite resin molding method capable of forming an optical member having excellent optical characteristics at a low cost and in a large amount by using a nanocomposite resin containing inorganic fine particles and a thermoplastic resin, and an optical material comprising the nanocomposite resin. A method for producing a preform for a member is provided.
A preform is made of a nanocomposite resin containing inorganic fine particles and a thermoplastic resin, and has convex and curved surfaces on both sides. The preform 1 includes a liquid phase 4 in which the nanocomposite resin is insoluble and a gas phase in which the solution 2 containing the nanocomposite resin and at least one solvent that imparts fluidity to the nanocomposite resin is superimposed on the liquid phase 4. The first interface 2a of the solution 2 that is in contact with the liquid phase 4 and the second interface 2b of the solution 2 that is in contact with the gas phase are made convex surfaces by interfacial tension, and at least from the solution 2 It is formed through a process of removing one kind of solvent and gelling the solution 2.
[Selection] Figure 1

Description

  The present invention relates to a method for molding a nanocomposite resin containing inorganic fine particles and a thermoplastic resin, and a method for producing a preform for an optical member comprising the nanocomposite resin.

  With recent improvements in performance, miniaturization, and cost reduction of optical information recording devices such as portable cameras and DVDs, CDs, and MO drives, optical members such as optical lenses and filters used in these optical devices Improvement of optical characteristics, size reduction, and cost reduction are strongly desired. In addition, plastic lenses can be processed into various shapes, are lighter and harder to break than glass lenses, and are more advantageous in terms of cost than glass lenses. Is also spreading rapidly.

  Along with this, there is a need to increase the refractive index of plastic lens materials and to stabilize the refractive index of plastic lenses against thermal expansion and temperature changes in order to reduce the size and thickness of plastic lenses. It has become. As one of the solutions, a nanocomposite resin in which inorganic fine particles such as metal oxide fine particles are dispersed in a thermoplastic resin is used as the material of the plastic lens, thereby improving the refractive index, thermal expansion and temperature. Various attempts have been made to suppress the variation of the refractive index due to the change.

  The refractive index and thermal stability of an optical member made of a nanocomposite resin are typically improved by increasing the amount of inorganic fine particles added, while the fluidity of the nanocomposite resin is reduced. In particular, in order to improve the refractive index, it is necessary to disperse a large amount of inorganic fine particles, and with the recent demand for higher refractive index, the decrease in fluidity of the nanocomposite resin has become remarkable. For this reason, it is difficult to obtain the fluidity of the resin necessary for the injection molding with the nanocomposite resin, and there is a concern about the transfer failure of the fine structure according to the injection molding. Therefore, conventionally, a method of forming an optical member by hot press molding a preform made of a nanocomposite resin has been proposed (see, for example, Patent Document 1).

  And as a method of manufacturing a preform using a nanocomposite resin, for example, a method of melting and mixing a thermoplastic resin and inorganic fine particles and injection molding (for example, see Patent Document 1), or a thermoplastic resin in a solvent Further, a method in which a solution in which inorganic fine particles are mixed is put into a metal or ceramic mold and the solvent is removed by heat or the like (see, for example, Patent Documents 2 and 3) is known.

Also, as a method for molding a plastic material such as plastic, there is a technique in which a plastic material is disposed between two liquid phases, and the shape of the interface contacting each liquid phase is controlled by interfacial tension, for example, to form a convex curve shape. It has been proposed (see, for example, Patent Document 4). In this technology, non-polymerizable materials such as thermoplastic materials and polymerizable materials that polymerize by electromagnetic waves such as light are used as plastic materials, and powders such as organic, inorganic, and metal materials are added as necessary. Is done.
JP 2006-343387 A JP 2003-147090 A JP 2002-047425 A JP 2003-181856 A

  In Patent Document 1, a preform is hot press-molded to form a desired optical member. Here, the nanocomposite resin is poor in fluidity, and when the adhesive interface between the nanocomposite resins is formed at the time of hot press molding, the mixing of the nanocomposite resin at the adhesive interface becomes insufficient. As a result, a weld line that becomes an optical defect may occur at the interface. Therefore, it is necessary to prevent an adhesion interface between nanocomposite resins during hot press molding.

  In addition, when producing a preform using a nanocomposite resin, injection molding may cause difficulty in molding because the nanocomposite resin is difficult to obtain resin fluidity even at high temperatures. There is a problem that the inorganic fine particles are locally aggregated and the dispersion density is not constant, and it is difficult to obtain desired optical characteristics (transparency, refractive index, etc.). In addition, optical members are required to have high quality, and the material remaining in the runner in the injection molding is discarded without being reused because there is a risk of quality deterioration. Therefore, according to the injection molding, the nanocomposite resin material Loss is relatively large, and becomes a factor that hinders reduction of preform manufacturing costs.

  On the other hand, according to the solution method in which a solution containing a nanocomposite resin is put into a mold and molded, the above-described problems caused by injection molding can be solved. However, according to the solution method, the mold is occupied while the solvent is removed, and a large number of molds are required to manufacture a large amount of the preform, which is costly.

  According to the method of forming by interfacial tension disclosed in Patent Document 4, a mold is not required, so that cost can be reduced. However, the nanocomposite resin is difficult to obtain fluidity even at a high temperature as described above, and it is difficult to control the shape of the interface by the interfacial tension, and the dispersion density of the inorganic fine particles is not constant, which is desirable. There is a problem that it is difficult to obtain the optical characteristics. In addition, if a photocurable resin is used instead of the thermoplastic resin, the type of resin is limited.

  The present invention has been made in view of such a conventional problem, and it is possible to form an optical member having excellent optical characteristics at low cost and in large quantities using a nanocomposite resin containing inorganic fine particles and a thermoplastic resin. An object of the present invention is to provide a method for forming a nanocomposite resin, and a method for producing a preform for an optical member comprising the nanocomposite resin.

The above object of the present invention is achieved by the following nanocomposite resin molding method.
(1) A method for forming a nanocomposite resin containing inorganic fine particles and a thermoplastic resin, the solution comprising the nanocomposite resin and one or more solvents that impart fluidity to the nanocomposite resin, The nanocomposite resin is disposed so as to provide an interface with an insoluble liquid phase and a fluid phase overlapping the liquid phase, the first interface of the solution in contact with the liquid phase, and the solution in contact with the fluid phase A method for forming a nanocomposite resin, comprising a step of forming a convex curved surface by interfacial tension, removing at least one kind of the solvent from the solution, and gelling the solution.
(2) A method for forming a nanocomposite resin containing inorganic fine particles and a thermoplastic resin, the solution comprising the nanocomposite resin and one or more solvents that impart fluidity to the nanocomposite resin, The nanocomposite resin is disposed in an insoluble liquid phase, the interface of the solution in contact with the liquid phase is formed into a convex curved surface by interfacial tension, at least one kind of the solvent is removed from the solution, and the solution is gelled A method for forming a nanocomposite resin, comprising a solvent removing step for converting into a nanocomposite.
(3) The nanocomposite resin according to (1) or (2), wherein the solvent removed in the solvent removal step is soluble in the liquid phase, and the solvent is absorbed into the liquid phase Molding method.
(4) The solution includes a first solvent that dissolves the nanocomposite resin to form a gel composition, and a second solvent that solates the gel composition. In the solvent removal step, the solution The method for molding a nanocomposite resin according to any one of (1) to (3), wherein the second solvent is removed from the solution and the solution is gelled.
(5) The method for molding a nanocomposite resin according to (4), wherein the first solvent is toluene and the second solvent is ethanol.
(6) The method for molding a nanocomposite resin according to (5), wherein the liquid phase is water.

The above-mentioned object of the present invention is achieved by the following preform manufacturing method.
(7) A method for producing a preform for an optical member comprising a nanocomposite resin containing inorganic fine particles and a thermoplastic resin, wherein the nanocomposite resin molding method according to any one of (1) to (6) is used. A method for producing a preform, wherein the front and back surfaces are formed into convex curved surfaces.

  According to the method for molding a nanocomposite resin according to the present invention, fluidity is imparted to the nanocomposite resin using a solvent. Thereby, it is possible to easily control the shape of the interface of the solution containing the nanocomposite resin and the solvent by the interfacial tension, and to uniformly disperse the inorganic fine particles, thereby improving the optical characteristics. Then, the solution is disposed between or in the liquid phase and the fluid phase overlapping the liquid phase, and the solvent is removed by forming the interface of the solution into a convex curved surface by interfacial tension. This eliminates the need for a mold and can reduce the cost. The nanocomposite resin thus molded is formed into a convex curved surface.

  Further, according to the preform manufacturing method of the present invention, the front and back surfaces are formed into convex curved surfaces. When the preform thus formed is hot press-molded into an optical member having a convex optical surface, the shape of the preform approximates to avoid the occurrence of an adhesive interface between nanocomposite resins. . In addition, when hot press molding is performed on an optical member having a flat or concave optical surface, since the hot press proceeds from the center of the preform, generation of an adhesive interface between nanocomposite resins is avoided. As a result, it is possible to prevent generation of a weld line that becomes an optical defect and to form an optical member having excellent optical characteristics. Furthermore, since the hot press proceeds from the center of the preform, air is easily pushed out, thereby preventing the generation of bubbles and improving the yield.

  As described above, according to the present invention, an optical member having excellent optical characteristics can be formed in a large amount at a low cost by using a nanocomposite resin containing inorganic fine particles and a thermoplastic resin.

  Hereinafter, preferred embodiments of a method for molding a nanocomposite resin and a method for producing a preform according to the present invention will be described in detail with reference to the drawings.

<First Embodiment>
FIG. 1 is a diagram showing each step in the nanocomposite resin molding method and preform manufacturing method of the first embodiment. In this embodiment, the preform 1 whose front and back surfaces are formed into convex curved surfaces is formed using a nanocomposite resin containing inorganic fine particles and a thermoplastic resin. The details of the nanocomposite resin used in the present invention will be described later.

  As shown in FIG. 1 (A), a solution 2 containing a nanocomposite resin and a solvent that imparts fluidity to the nanocomposite resin is weighed in a predetermined amount using a measuring instrument such as a dispenser, and placed in a container 3. It is supplied dropwise. The container 3 contains a liquid 4 insoluble in the nanocomposite resin.

  In this embodiment, the specific gravity of the solution 2 containing nanocomposite resin is smaller than the specific gravity of the liquid 4 accommodated in the container 3. Accordingly, as shown in FIG. 1B, the solution 2 supplied to the container 3 floats on the surface of the liquid 4, that is, the solution 2 is composed of the liquid (liquid phase) 4 and the atmosphere (gas phase (fluid phase)). Between the liquid phase 4 and the gas phase.

  In the present embodiment, the solution 2 is disposed between the liquid phase 4 and the gas phase, but the present invention is not limited to this. For example, instead of the gas phase, the liquid phase (fluid phase) insoluble in the nanocomposite resin may be superimposed on the liquid phase 4 and the solution 2 may be disposed between the two liquid phases. Further, as will be described in detail later, the specific gravity of the solution 2 may be substantially equal to the specific gravity of the liquid phase 4, and the solution 2 may be disposed in the liquid phase 4.

  In the present embodiment, the solution 2 is supplied dropwise, but the present invention is not limited to this. For example, when the solution 2 is disposed between the two liquid phases, a nozzle discharge port is provided at a position facing the two liquid phases, and the solution 2 is discharged from the nozzle to arrange the solution 2. Alternatively, the solution 2 may be dropped and floated on the surface of the lower liquid phase 4, and then the upper liquid phase may be covered.

  The first interface 2 a of the solution 2 in contact with the liquid phase 4 has a convex curved surface due to the interfacial tension acting with the liquid phase 4. Moreover, the 2nd interface 2b of the solution 2 which contacts a gaseous phase is a convex curve by the interfacial tension which acts between gaseous phases.

  The concentration of the nanocomposite resin contained in the solution 2 is preferably 10 wt. % To 90 wt. %, More preferably 15 wt. % To 50 wt. %. Depending on the phase (solution 4 or gas phase) with which the solution 2 is in contact, the concentration of the nanocomposite resin is 10 wt. If it is less than%, the interface is difficult to be a convex curved surface. The concentration of the nanocomposite resin is 15 wt. If it is at least%, it is possible to cope with various shapes in terms of thickness and radius of curvature of the convex curved surface of the interface. The concentration of the nanocomposite resin is 90 wt. If it exceeds%, the fluidity of the solution 2 is insufficient, and it becomes difficult to control the shape of the interface by the interfacial tension. The interface can be formed into a convex curved surface in a realistic time because the concentration of the nanocomposite resin is 50 wt. % Or less.

  As shown in FIGS. 1C and 1D, the solvent is removed from the solution 2 while maintaining the convex curved surface shapes of the first interface 2a and the second interface 2b of the solution 2. By removing the solvent from the solution 2, the nanocomposite resin loses its fluidity and gels and finally solidifies.

  The solution 2 is in contact with the liquid phase 4 at the first interface 2 a, and the liquid phase 4 can absorb at least one solvent contained in the solution 2 and remove the solvent from the solution 2. For example, as the liquid phase 4, water can be preferably used from the viewpoint of easy handling, and the solvent can be absorbed into the liquid phase 4 by making it hydrophilic, thereby removing the solvent. In the present embodiment, the solution 2 is in contact with the gas phase at the second interface 2b, and a volatile solvent or the like can be vaporized and removed.

  In the present invention, the solvent contained in the solution 2 may be one type of solvent as long as the fluidity can be imparted to the nanocomposite resin, but high fluidity is realized by combining a plurality of types of solvents. can do. In the present embodiment, the solution 2 includes a first solvent that dissolves the nanocomposite resin to form a gel composition, and a second solvent that solates the gel composition. These first solvent and The fluidity is imparted to the nanocomposite resin by the second solvent.

  Examples of the solvent contained in the solution 2 include acetic acid, acetone, acetonitrile, benzene, t-butanol, carbon disulfide, carbon tetrachloride, chloroform, cyclohexane, cyclopentane, decalin, dibromomethane, o-dichlorobenzene, and diethyl ether. 1,2-dichloroethane, 1,2-dichloroethylene Z, 1,2-dichloroethylene E, 1,1-dichloroethylene, dichloromethane, dimethoxymethane, dimethylacetamide, dimethyl carbonate, dimethyl ether, N, N-dimethylformamide, dimethyl sulfoxide, Dioxolane, methanol, ethanol, ethyl acetate, ethylene carbonate, dichlorodifluoromethane, chlorodigluoromethane, formamide, hexachloroacetone, hexafluorodichloropropane, hexa It is selected from, but not limited to, til phosphoramide, methyl chloride, morpholine, nitromethane, pyridine, quinoline, sulfur dioxide, 2,2-tetrachloroethane, tetrahydrofuran, tetramethylurea, toluene, trichloroethylene, butyl acetate, etc. .

  The solution 2 containing the first solvent and the second solvent loses fluidity when the second solvent is removed and gels, and further solidifies when the first solvent is removed. When at least one of the first solvent and the second solvent is absorbed and removed by the liquid phase 4, from the viewpoint of ease of handling, when water is used for the liquid phase 4, the first solvent and As a combination of the second solvent, it is preferable that either one is a hydrophilic solvent and the other is a hydrophobic solvent. For example, in the present embodiment, the liquid phase 4 is water, hydrophobic toluene is used as the first solvent, and hydrophilic ethanol is used as the second solvent. As shown in FIG. 1C, the solution 2 configured in this manner is absorbed and removed by the liquid phase 4 by ethanol as the second solvent, and thereby gelates. Further, as shown in FIGS. 1C and 1D, toluene as the first solvent is volatile, is vaporized and released into the gas phase, and is removed from the solution 2.

  By removing toluene, which is the first solvent, and ethanol, which is the second solvent, from the solution 2, as shown in FIG. 1 (E), a solid content 1 ′ that is hard enough to be deformed even by its own weight is formed. Some moisture and solvent remain in the solid content 1 ′, and these moisture and solvent are removed by drying to form the preform 1 shown in FIG. The drying condition may be either vacuum drying or air drying, and is preferably performed at 100 ° C. or lower. When it is dried at a temperature exceeding 100 ° C., the internal moisture rapidly expands and bubbles may be generated in the solid content 1 ′.

  The preform 1 formed as described above has its front and back surfaces formed into convex curved surfaces. When the preform 1 thus molded is hot-press molded to an optical member having a convex curved optical surface, for example, the shape approximates to avoid the occurrence of an adhesive interface between nanocomposite resins. Is done. In addition, when hot press molding is performed on an optical member having a flat or concave optical surface, the hot press proceeds from the center of the preform 1, thereby avoiding the occurrence of an adhesive interface between nanocomposite resins. .

  As described above, according to the nanocomposite resin molding method of the present embodiment, fluidity is imparted to the nanocomposite resin using a solvent. Thereby, the shape of the interfaces 2a and 2b of the solution 2 containing the nanocomposite resin and the solvent can be easily controlled by the interfacial tension, and the optical properties can be improved by uniformly dispersing the inorganic fine particles. it can. And the solution 2 is arrange | positioned between the liquid phase 4 and a gaseous phase, and the interface 2a, 2b of the solution 2 is shape | molded by the interfacial tension to a convex curve, and the solvent is removed. This eliminates the need for a mold and can reduce the cost. The nanocomposite resin thus molded is formed into a convex curved surface.

  Moreover, according to the preform manufacturing method of the present embodiment, the front and back surfaces of the preform 1 are formed into convex curved surfaces. When the preform 1 thus formed is hot press-molded into an optical member having a convex optical surface, the shape approximates to avoid the occurrence of an adhesive interface between nanocomposite resins. The In addition, when hot press molding is performed on an optical member having a flat or concave optical surface, the hot press proceeds from the center of the preform 1, thereby avoiding the occurrence of an adhesive interface between nanocomposite resins. . As a result, it is possible to prevent generation of a weld line that becomes an optical defect and to form an optical member having excellent optical characteristics. Further, since the hot press proceeds from the center of the preform 1, air is easily pushed out, thereby preventing the generation of bubbles and improving the yield.

  Based on the above, an optical member having excellent optical characteristics can be formed at a low cost and in large quantities using a nanocomposite resin containing inorganic fine particles and a thermoplastic resin.

Second Embodiment
FIG. 2 is a diagram showing each step in the nanocomposite resin molding method and preform manufacturing method of the second embodiment. Note that elements common to the above-described first embodiment are denoted by the same reference numerals in the drawing, and description thereof is omitted or simplified.

  As shown in FIG. 2, in this embodiment, the specific gravity of the solution 2 containing the nanocomposite resin is substantially equal to the specific gravity of the liquid 4 contained in the container 3, and the solution 2 is disposed in the liquid phase 4. Like to do. In addition, when the discharge port of the nozzle which discharges the solution 2 is provided in the liquid phase 4 and the solution 2 is discharged from the nozzle and the solution 2 is disposed, it is necessary to change the direction of the nozzle depending on the specific gravity of the solution 2. . For example, when the specific gravity of the solution 2 is smaller than the specific gravity of the liquid phase 4, the nozzle is directed upward.

  The solution 2 disposed in the liquid phase 4 has a substantially spherical shape due to the interfacial tension acting with the liquid phase 4. Then, as shown in FIGS. 2C and 2D, the solvent is removed from the solution 2 while maintaining the substantially spherical shape of the solution 2. By removing the solvent from the solution 2, the nanocomposite resin loses its fluidity and gels and finally solidifies.

  Here, also in the present embodiment, the liquid phase 4 is water, and in the solution 2, toluene as a first solvent that dissolves the nanocomposite resin to form a gel composition, and this gel composition is made into a sol. Ethanol as a second solvent is included. From the solution 2 arranged in the liquid phase 4, mainly hydrophilic ethanol is absorbed and removed by the liquid phase 4, whereby the solution 2 is gelled. Hydrophobic toluene is also gradually absorbed by the liquid phase 4 and removed, although it takes more time than volatilization and removal.

  By removing toluene, which is the first solvent, and ethanol, which is the second solvent, from the solution 2, as shown in FIG. 2E, a solid content 11 ′ that is hard enough to be deformed even by its own weight is formed. This solid content 11 ′ is dried to form the preform 11 shown in FIG.

  The preform 11 formed as described above has a substantially spherical shape, with the upper half as the front and the lower half as the back, and the front and back are formed into convex curved surfaces. When the preform 11 thus molded is hot-press molded into an optical member having a convex curved optical surface, for example, the shape approximates to avoid the occurrence of an adhesive interface between nanocomposite resins. Is done. In addition, when hot press molding is performed on an optical member having a flat or concave optical surface, the hot press proceeds from the center of the preform 1, thereby avoiding the occurrence of an adhesive interface between nanocomposite resins. .

<Nanocomposite resin>
Hereinafter, the nanocomposite resin used in the present invention will be described in detail.

[Inorganic fine particles]
The organic-inorganic composite material used in the present invention is inorganic fine particles having a number average particle size of 1 to 15 nm. If the number average particle size of the inorganic fine particles is too small, the characteristics unique to the substance constituting the fine particles may change. Conversely, if the number average particle size is too large, the effect of Rayleigh scattering becomes remarkable, and the transparency of the organic-inorganic composite material is extremely high. May fall. Therefore, the number average particle size of the inorganic fine particles in the present invention needs to be 1 to 15 nm, preferably 2 to 13 nm, and more preferably 3 to 10 nm.

  Examples of the inorganic fine particles used in the present invention include oxide fine particles, sulfide fine particles, selenide fine particles, telluride fine particles and the like. More specifically, titania fine particles, zinc oxide fine particles, zirconia fine particles, tin oxide fine particles, zinc sulfide fine particles and the like can be mentioned, preferably titania fine particles, zirconia fine particles and zinc sulfide fine particles, more preferably titania fine particles. Although it is a zirconia fine particle, it is not limited to these. In the present invention, one type of inorganic fine particles may be used, or a plurality of types of inorganic fine particles may be used in combination.

  The refractive index at a wavelength of 589 nm of the inorganic fine particles used in the present invention is preferably 1.90 to 3.00, more preferably 1.90 to 2.70, and 2.00 to 2.70. More preferably it is. If inorganic fine particles having a refractive index of 1.90 or more are used, it becomes easy to produce an organic-inorganic composite material having a refractive index greater than 1.65. If inorganic fine particles having a refractive index of 3.00 or less are used, the transmittance is 80%. There exists a tendency which is easy to produce the above organic inorganic composite material. In addition, the refractive index in this invention is the value measured at 25 degreeC about the light of wavelength 589nm with the Abbe refractometer (Atago DR-M4).

［Ｒ^１１、Ｒ^１２、Ｒ^１３、Ｒ^１４は、それぞれ独立に水素原子、置換または無置換のアルキル基、置換または無置換のアルケニル基、置換または無置換のアルキニル基、あるいは、置換または無置換のアリール基を表す。］、−ＳＯ_３Ｈ、−ＯＳＯ_３Ｈ、−ＣＯ_２Ｈ、または−Ｓｉ（ＯＲ^１５）_ｍ１Ｒ^１６ _３−ｍ１［Ｒ^１５、Ｒ^１６はそれぞれ独立に水素原子、置換または無置換のアルキル基、置換または無置換のアルケニル基、置換または無置換のアルキニル基、あるいは、置換または無置換のアリール基を表し、ｍ１は１〜３の整数を表す。］
（２）疎水性セグメントおよび親水性セグメントで構成されるブロック共重合体；
が好ましい例として挙げられる。 [Thermoplastic resin]
The structure of the thermoplastic resin used in the present invention is not particularly limited. For example, poly (meth) acrylic acid ester, polystyrene, polyamide, polyvinyl ether, polyvinyl ester, polyvinyl carbazole, polyolefin, polyester, polycarbonate, polyurethane, polythiol. Examples of the resin having a known structure such as urethane, polyimide, polyether, polythioate, polyetherketone, polysulfone, and polyethersulfone can be exemplified. In the present invention, inorganic fine particles are present at least at the end of the polymer chain or at the side chain. A thermoplastic resin having a functional group capable of forming an arbitrary chemical bond with is particularly preferable. As such a thermoplastic resin,
(1) a thermoplastic resin having a functional group selected from the following at the polymer chain end or side chain;

[R ¹¹ , R ¹² , R ¹³ and R ¹⁴ are each independently a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted alkynyl group, or a substituted or unsubstituted group. Represents an aryl group. _{], - SO 3 H, -OSO} 3 H, -CO 2 H or _{^{-Si (OR 15) m1 R 16}} 3-m1 [R 15, R 16 are each independently a hydrogen atom, a substituted or unsubstituted alkyl group, Represents a substituted or unsubstituted alkenyl group, a substituted or unsubstituted alkynyl group, or a substituted or unsubstituted aryl group, and m1 represents an integer of 1 to 3. ]
(2) a block copolymer composed of a hydrophobic segment and a hydrophilic segment;
Is a preferred example.

[Thermoplastic resin (1)]
Hereinafter, the thermoplastic resin (1) will be described in detail. The thermoplastic resin (1) used in the present invention has a functional group capable of forming a chemical bond with inorganic fine particles at the polymer chain terminal and side chain. Here, the “chemical bond” includes, for example, a covalent bond, an ionic bond, a coordination bond, a hydrogen bond, and the like, and when there are a plurality of functional groups, each can form a chemical bond different from the inorganic fine particles. It may be. Whether or not a chemical bond can be formed is determined by whether or not the functional group of the thermoplastic resin can form a chemical bond with the inorganic fine particle when the thermoplastic resin and the inorganic fine particle are mixed in an organic solvent. All of the functional groups of the thermoplastic resin may form chemical bonds with the inorganic fine particles, or some of them may form chemical bonds with the inorganic fine particles.

The thermoplastic resin used in the present invention is particularly preferably a copolymer having a repeating unit represented by the following general formula (1). Such a copolymer can be obtained by copolymerizing a vinyl monomer represented by the following general formula (2).

In the general formulas (1) and (2), R represents a hydrogen atom, a halogen atom or a methyl group, and X represents —CO ₂ —, —OCO—, —CONH—, —OCONH—, —OCOO—, It represents a divalent linking group selected from the group consisting of —O—, —S—, —NH—, and a substituted or unsubstituted arylene group, more preferably —CO ₂ — or a p-phenylene group.

  Y represents a divalent linking group having 1 to 30 carbon atoms. 1-20 are preferable, as for carbon number, 2-10 are more preferable, and 2-5 are more preferable. Specific examples include an alkylene group, an alkyleneoxy group, an alkyleneoxycarbonyl group, an arylene group, an aryleneoxy group, an aryleneoxycarbonyl group, and a combination thereof, and an alkylene group is preferable.

  q represents the integer of 0-18. More preferably, it is an integer of 0-10, More preferably, it is an integer of 0-5, Most preferably, it is an integer of 0-1.

  Z is a functional group represented by the above [Chemical Formula 1].

Specific examples of the monomer represented by the general formula (2) are given below, but the monomer that can be used in the present invention is not limited thereto.

  Other types of monomers copolymerizable with the monomer represented by the general formula (2) in the present invention include those described in Polymer Handbook 2nd ed., J. Brandrup, Wiley lnterscience (1975) Chapter 2 Page 1 to 483. Can be used.

  Specifically, for example, styrene derivatives, 1-vinylnaphthalene, 2-vinylnaphthalene, vinylcarbazole, acrylic acid, methacrylic acid, acrylic esters, methacrylic esters, acrylamides, methacrylamides, allyl compounds, vinyl ethers , Vinyl esters, dialkyl itaconates, dialkyl esters of the above fumaric acid, monoalkyl esters, and the like.

  The weight average molecular weight of the thermoplastic resin (1) used in the present invention is preferably 1,000 to 500,000, more preferably 3,000 to 300,000, and 10,000 to 100,000. It is particularly preferred that When the weight average molecular weight of the thermoplastic resin (1) is 500,000 or less, the moldability tends to be improved, and when it is 1,000 or more, the mechanical strength tends to be improved.

  In the thermoplastic resin (1) used in the present invention, the average number of functional groups bonded to inorganic fine particles is preferably from 0.1 to 20, and preferably from 0.5 to 10, per polymer chain. More preferably, it is particularly preferably 1 to 5. If the content of the functional group is 20 or less on average per polymer chain, the thermoplastic resin (1) is coordinated with a plurality of inorganic fine particles to prevent high viscosity and gelation in solution. It tends to be easy. Moreover, if the number of average functional groups per polymer chain is 0.1 or more, the inorganic fine particles tend to be dispersed stably.

  The glass transition temperature of the thermoplastic resin (1) used in the present invention is preferably 80 ° C to 400 ° C, and more preferably 130 ° C to 380 ° C. If a resin having a glass transition temperature of 80 ° C. or higher is used, an optical component having sufficient heat resistance can be easily obtained, and if a resin having a glass transition temperature of 400 ° C. or lower is used, molding tends to be easily performed.

  As described above, the nanocomposite resin used in the present invention has a high refractive index and high transparency of an organic-inorganic composite material in which inorganic fine particles are dispersed by giving a unit structure having a specific structure in the resin. It is possible to improve the releasability from the molding die without damaging.

  According to the above materials, an organic-inorganic composite material having both excellent releasability, high refraction, and transparency, and an optical device that includes both high accuracy, high transparency, and high refraction. A member can be provided.

  Examples will be described below.

A nanocomposite resin and a solution containing the nanocomposite resin and a solvent were prepared as follows.
-Thermoplastic resin: Styrene polymer-Inorganic fine particles: Zirconia particles (particle size 5nm)
Solvent: toluene, ethanol (mixing ratio (toluene: ethanol) 95: 5)
Nanocomposite resin concentration: 36.1 wt. %

  277 microliters of the above solution was weighed using a dispenser “Measuring Master mpp-1” manufactured by Musashi Engineering, and placed between water (liquid phase) and atmosphere (gas phase). This state was maintained for 6 hours, and it was confirmed that the solid content was not deformed even by its own weight. The taken-out solid content was dried at 100 ° C. for 24 hours using a blower dryer to form a preform. Under the above conditions, the diameter is 7 to 8 mm, the radius of curvature of the surface in contact with water is 3 to 4 mm, and the radius of curvature of the surface in contact with the atmosphere is 3.5 to 4.5 mm. Both were able to form a preform formed into a convex curved surface.

The above-mentioned preform was hot press-molded using a press apparatus having a concave curved molding surface having a diameter of 8 mm and a curvature radius of 4.5 mm in each of the upper mold and the lower mold. The conditions for hot press molding are as follows.
Preform preheating time: 180 ° C, 30s
・ Pressing temperature: 180 ℃
・ Pressing force: 1.95 MPa
・ Press holding time: 2 min.
Cooling rate: 2 ° C / s
・ Take-off temperature: 30 ℃
When the preform was hot-press molded under the above conditions, a good molded product without a weld line could be obtained.

It is a figure which shows each process in the shaping | molding method of nanocomposite resin of 1st Embodiment, and the manufacturing method of preform. It is a figure which shows each process in the shaping | molding method of the nanocomposite resin of 2nd Embodiment, and the manufacturing method of preform.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Preform 2 Solution 2a 1st interface of solution 2b 2nd interface of solution 3 Container 4 Liquid phase

Claims (7)

A method of molding a nanocomposite resin containing inorganic fine particles and a thermoplastic resin,
A solution containing the nanocomposite resin and at least one solvent that imparts fluidity to the nanocomposite resin has an interface with the liquid phase in which the nanocomposite resin is insoluble and the fluid phase overlapping the liquid phase. Arranged to give and
A first interface of the solution in contact with the liquid phase and a second interface of the solution in contact with the fluid phase to form a convex curved surface by interfacial tension;
A method for molding a nanocomposite resin, comprising: a solvent removal step of removing at least one kind of the solvent from the solution to gel the solution. A method of molding a nanocomposite resin containing inorganic fine particles and a thermoplastic resin,
Placing a solution containing the nanocomposite resin and one or more solvents that impart fluidity to the nanocomposite resin in a liquid phase in which the nanocomposite resin is insoluble;
The interface of the solution in contact with the liquid phase is a curved surface by interfacial tension,
A method for molding a nanocomposite resin, comprising: a solvent removal step of removing at least one kind of the solvent from the solution to gel the solution.   The method for molding a nanocomposite resin according to claim 1 or 2, wherein the solvent removed in the solvent removal step is soluble in the liquid phase, and the solvent is absorbed into the liquid phase. . The solution includes a first solvent that dissolves the nanocomposite resin to form a gel composition, and a second solvent that solates the gel composition;
The method for molding a nanocomposite resin according to any one of claims 1 to 3, wherein, in the solvent removal step, the second solvent is removed from the solution to gel the solution.   The method for molding a nanocomposite resin according to claim 4, wherein the first solvent is toluene and the second solvent is ethanol.   The method for molding a nanocomposite resin according to claim 5, wherein the liquid phase is water. A method for producing a preform for an optical member comprising a nanocomposite resin containing inorganic fine particles and a thermoplastic resin,
A method for manufacturing a preform, wherein the front and back surfaces are formed into convex curved surfaces by the method for forming a nanocomposite resin according to any one of claims 1 to 6.

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