JP2001301098A - Support for image material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a support for an image material excellent in apparent gloss feeling and smoothness and also excellent in the apparent gloss feeling and smoothness of an image forming layer when the image forming layer such as a colorant receiving layer or the like is provided on the support. SOLUTION: The support for the image material is obtained by coating both surfaces of paper with a resin having film forming capacity. The glossiness prescribed by JIS P8142 of the surface on the image forming side of the paper is 20% or more and the center average roughness (SRa value) of the surface on the image forming side of the support for the image material is 0.75 μm or less at the time of measurement under a cut-off condition of 6-7 mm.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a support for an image material for recording an image thereon, such as a support for an image material, for example, a silver halide photographic paper, an ink jet recording paper, a thermal transfer recording image receiving sheet and the like. It is about the body.

[0002]

2. Description of the Related Art Conventionally, as a support used for an image material such as silver halide photographic printing paper, ink jet recording paper, and thermal transfer recording image receiving sheet, a resin-coated support having a base paper surface coated with a resin capable of forming a film. Is well known. Image materials such as silver halide photographic printing paper, ink jet recording paper, and thermal transfer recording image receiving sheets require high smoothness and glossiness. For this reason, resin-coated supports also require smoothness and gloss. High degree is required. Various improvements have been proposed for producing a resin-coated paper-type support having high smoothness and glossiness. For example, JP-A-58-68037, JP-A-60-69649, JP-A-61-132949, JP-A-61-35442,
JP-A-63-173045, JP-A-58-37642, JP-A-63-291054, JP-A-60-126397, JP-A-61
-284762, JP-A-63-204250, JP-A-64-205
No. 41 discloses various techniques for improving smoothness. Japanese Patent Application Laid-Open No. 2000-19684 discloses a resin-coated paper-type support in which a paper provided with a coating layer made of a coating composition containing at least a pigment and a binder is used as a substrate. The paper substrate on the side where an image is to be provided is coated with a resin layer (A) containing a resin capable of forming a film, and the paper substrate on the opposite side is coated with a resin layer (B) containing a polyethylene resin as a main component. The pulp fiber length is 0.60 mm or less, and the density of the paper substrate of the image material support is 1.05 mm or less.
The support for image materials coated with a resin layer (B) having a g / cm ^{3 of} less than 200 m / min and a polyethylene resin as a main component has good apparent glossiness, curl properties and cuttability. Is disclosed. The above-mentioned publication also states that a paper substrate having a center plane average roughness SRa of 1.0 μm or less at a cutoff value of 0.8 mm is preferable from the viewpoint of glossiness. However, there is still room for improvement in the apparent glossiness and smoothness of the resin-coated paper type support, and further improved glossiness and smoothness are desired.

[0003]

SUMMARY OF THE INVENTION It is an object of the present invention to provide an image forming layer having an excellent glossiness and smoothness when an image forming layer such as a color material image receiving layer is provided thereon. It is an object of the present invention to provide a support for an image material having excellent feeling and smoothness.

[0004]

The above object is attained by providing the following support for an image material. (1) An image material support coated on both sides of a paper with a resin capable of forming a film, and the glossiness specified by JIS P8142 on the side of the paper on which an image is formed is 20. % Or more, and the center surface average roughness (SRa value) of the surface on the image forming side of the image material support.
Is 0.75 μm or less when measured under conditions of a cutoff of 6 to 7 mm. (2) The support for an image material according to (1), wherein the glossiness is 40% or more. (3) The image material support as described in (1) or (2) above, wherein the paper having a surface glossiness of 20% or more specified in JIS P8142 is a coated paper.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention relates to a paper coated with a resin capable of forming a film, the surface on which an image is to be formed of JI.
The glossiness specified by SP8142 is 20% or more, and the surface of the image material support on which an image is formed has a center plane average roughness (SRa value) of cutoff 6 to 7 m.
m is 0.75 μm or less under the condition of m. Here, the “side on which an image is formed” means the side on which an image forming layer is provided on a paper or a support for an image material. By satisfying these two conditions, it is possible to obtain a support for an image material having an excellent glossiness and smoothness. Further, when an image forming layer is provided on such a support for an image material, an image forming layer having excellent glossiness and smoothness can be obtained, and when an image is formed on this image forming layer, the image forming layer is formed. The image portion is excellent in apparent glossiness and smoothness. Here, the image-forming layer refers to an ink-jet ink receiving layer, a thermal transfer image-receiving layer, a heat-sensitive recording layer, a silver halide emulsion layer, etc., but is not particularly limited as long as it is an image-forming layer, and may be any image-forming layer. . The present inventors have found that the evaluation of the apparent glossiness of the support for an image material by a sensory test and the evaluation of the surface roughness by the center plane average roughness (SRa value) cut the center plane average roughness. Off 6
When measured under conditions of up to 7 mm, a good match was found. When the average surface roughness (SRa value) measured at a cutoff of 6 to 7 mm was 0.75 μm or less, a high apparent glossiness was observed. You have reached what you get. The irregularities on the surface of the paper are not uniform, and there are wavy irregularities of various wavelengths. Here, the measurement under the condition of a cutoff of 6 to 7 mm means that the measurement is performed on the irregularities with a wavelength of 6 to 7 mm. I do.

The method of measuring the center plane average roughness (SRa value) under the condition of a cutoff of 6 to 7 mm is as follows. Equipment used Kuroda Seiko Co., Ltd. Surface profile measuring device Nano Metro 11
0F Measurement and analysis conditions Scanning direction: MD direction of sample Measurement length: 50 mm in X direction, 40 mm in Y direction Measurement pitch: 0.15 mm in X direction, 0.2 mm in Y direction Scanning speed: 30 mm / sec Bandpass filter: 6 to 7 mm Filter tilt: -12 dB / Oct Effective range of filter tilt: up to 1/2 wavelength (3 mm here) on the short wavelength side Double wavelength (14 m here) on the long wavelength side
To m) Further, JIS P-8142 means a 75 degree specular gloss test method for paper and paperboard.

The paper used for the image material support of the present invention is J
The glossiness according to ISP-8142 is 20% or more, preferably 40% or more. As such glossy paper, paper provided with a coating layer, for example, art paper, coated paper,
Commercially available paper such as cast coat paper and baryta paper used for silver salt photographic supports and the like are also preferably used. The coating layer includes kaolin, calcined clay, heavy calcium carbonate, light calcium carbonate, satin white, titanium dioxide, aluminum hydroxide, silica, and plastic pigment as pigments, starch, modified starch, casein, polyvinyl alcohol, and SBR as binders. Is formed by applying an aqueous dispersion containing a dispersant, an antifoaming agent, a lubricant, a waterproofing agent, a viscosity modifier, a water retention agent, a preservative, and a dye as an auxiliary agent to paper. As a coating apparatus used for forming a coating layer, a roll coater, a gravure coater, a die coater, a curtain coater, a spray coater, a blade coater, a rod coater, an impregnating coater, a cast coater, an air knife coater, or the like is used. After forming the coating layer, as a finishing process,
By calendering the coating layer surface, smoothing,
Polishing may be performed.

As the resin having a film forming ability, a thermoplastic resin is preferable, and among them, a polyolefin resin is preferable. Examples of the polyolefin resin include homopolymers such as polyethylene, polypropylene, polybutene and polypentene, copolymers composed of two or more α-olefins such as ethylene-butylene copolymer, and mixtures thereof. Polyethylene resins are particularly preferred from the viewpoint of coating properties and adhesion to base paper. Examples of the polyethylene resin include low-density polyethylene, medium-density polyethylene, high-density polyethylene, linear low-density polyethylene, copolymers of ethylene with propylene, α-olefins such as butylene, carboxy-modified polyethylene, and the like, and mixtures thereof. Is mentioned. The density, melt flow rate (hereinafter simply abbreviated as MFR), molecular weight, and molecular weight distribution of the polyethylene resin can be used without any particular limitation, but usually the density is in the range of 0.90 to 0.97 g / cm3, Is 0.1g / 10
Min to 50 g / 10 min, preferably 0.3 g / 10 min MFR
Those having a range of 40 g / 10 minutes can be used alone or as a mixture.

Various additives can be contained in the resin having film forming ability. For the purpose of increasing the resolution of an image, it is preferable to add titanium dioxide.
As titanium dioxide, sulfuric acid method, chlorine method,
Various titanium dioxide pigments such as a rutile type, an anatase type, a surface treated with a hydrated metal oxide, and a surface treated with an organic compound can be used. In addition, white pigments such as zinc oxide, talc and calcium carbonate as pigments, stearic acid amides such as release agents, fatty acid amides such as arachidic acid amide, dispersants for pigments and zinc stearate as releasing agents, Fatty acid metal salts such as calcium stearate, aluminum stearate, magnesium stearate, zinc palmitate, zinc myristate, calcium palmitate, are disclosed in
No. 45, hindered phenol, hindered amine, phosphorus, various antioxidants such as sulfur, cobalt blue, ultramarine, celian blue, blue pigments and dyes such as phthalocyanine blue, cobalt violet,
Fast violet, magenta-based pigments and dyes such as manganese violet, quinacridone-based red pigments described in JP-B-4-2175, fluorescent whitening agents described in JP-A-2-254440, ultraviolet absorbers And other various additives can be appropriately combined and contained. These additives are preferably contained in the resin composition used in the practice of the present invention in combination or as a separate resin master batch or compound.

The resin coating thickness of the resin-coated paper in the present invention is suitably in the range of 4 μm to 100 μm on the image forming side, preferably in the range of 6 μm to 50 μm, and more preferably 9 μm.
Particularly preferred is a range of -35 µm. On the other side, a range of 4 μm to 100 μm is generally appropriate, and preferably a range of 6 μm to 50 μm. The resin of the resin film formed on the image forming side and the resin film formed on the opposite side are preferably the same.

In the present invention, as a method of coating a resin having a film forming ability on paper, the resin is cast on a running base paper by casting it from a slit die into a film form using a melt extruder. It is preferable to coat by a so-called melt extrusion coating method.

[0012]

The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the present invention is limited to these Examples. In the following, "%" and "part"
Represents "% by weight" and "parts by weight" unless otherwise specified. In the following, the “image forming side” has the same meaning as the “surface on which an image is formed”. Example 1 A wood pulp consisting of 100 parts of LBKP was beaten to a Canadian freeness of 300 ml with a double disc refiner, and 0.5 parts of epoxidized behenamide, 1.0 part of anionic polyacrylamide, 0.1 part of polyamide polyamine epichlorohydrin, and 0.5 part of cationic polyacrylamide were all used. Base paper having a basis weight of 170 g / m ^{2 was} produced by a fourdrinier paper machine at an absolute dry weight ratio to pulp. As a surface size, 0.04% of a fluorescent enhancer (trade name: WhitexBB, manufactured by Sumitomo Chemical Co., Ltd.) is added to a 4% aqueous solution of polyvinyl alcohol, impregnated with 0.5 g / m ² in absolute dry weight, dried, and adjusted to a density of 1.05 by calendering. I got the base paper.

After performing a corona discharge treatment on the wire side (back side) of the base paper, the following coating layer was provided. <Formation of coating liquid for coating layer> 147.5 g of ion-exchanged water 1.0 g of sodium hexametaphosphate 100.0 g of kaolin (Amazon Premium) were dispersed with a dissolver for 10 minutes. This is designated as solution A. Solution A 250 g Borax (10% aqueous solution) 50 g SN-307 (48% aqueous solution) 41.7 g (SBR latex manufactured by Sumika ABS Latex Co., Ltd.) 11 g of ion-exchanged water was mixed to obtain a coating solution for a coating layer.

The coating solution for the coating layer was applied with a wire bar coater and dried to provide a coating layer of 10 g / m ² . The coated paper provided with the above-mentioned coat layer was subjected to a super calender treatment (temperature: 80 ° C., linear pressure: 200 kg / cm 2 times). The surface of the coat layer of this coated paper,
The glossiness specified by JIS P8142 was 52%.

Next, the surface without the coating layer was coated with a high-density polyethylene to a thickness of 19 μm using a melt extruder to form a resin layer having a matte surface. This surface is the surface opposite to the image forming surface side of the image material support, and is hereinafter referred to as "back surface". After performing a corona discharge treatment on the resin layer on the “back side”, aluminum oxide (alumina sol 100, manufactured by Nissan Chemical Industries, Ltd.) and silicon dioxide (Snowtex O, manufactured by Nissan Chemical Industries, Ltd.) were used as antistatic agents. A dispersion liquid dispersed in water at a ratio of 1: 2 (weight ratio) was applied so that the weight after drying was 0.2 g / m ² .

After a corona discharge treatment is performed on the side of the coated paper on which the coating layer is provided, 10% by weight of anatase type titanium dioxide, a trace amount of ultramarine blue, and 0.01% by weight of a fluorescent whitening agent
(To polyethylene), low-density polyethylene having an MFR (melt flow rate) of 3.8 was melt-extruded to a thickness of 29 μm using a melt extruder to obtain a support for an image material of the present invention. Was. The center surface average roughness (SRa value) of the surface on the image forming side (this surface is sometimes referred to as “surface”) of the image material support is 6 to 7 mm in cutoff.
Was 0.48 μm when measured under the following conditions. The surface of the obtained image material support on the image forming side had good glossiness and smoothness in appearance.

Using the obtained support for image material, a coating material for a colorant receiving layer having the following composition was applied to prepare an image receiving sheet for ink jet. <Coating solution composition for colorant receiving layer> Silica fine particles: 9.9 parts (average primary particle diameter: 7 nm;
Aerosil 300, manufactured by Nippon Aerosil Co., Ltd.) Ion-exchange water 72.6 parts 1N ammonia water (pH regulator) 5.3 parts 9% aqueous solution of polyvinyl alcohol 31.4 parts (PVA420, Kuraray Co., Ltd., saponification degree 81.8%, polymerization degree 2000)

The coating material for the colorant receiving layer is applied at a coating amount of 200 cc / m ² using an extrusion die coater (coating step), and is heated to 80 ° C. (wind speed 3) with a hot air drier.
(8 m / sec) until the solid content concentration of the coating layer became 20%. The coating layer exhibited a constant rate of drying during this period. Immediately thereafter, it was immersed in a borax-containing solution (crosslinking agent-containing solution) having the following composition for 30 seconds to deposit 20 g / m ² thereof (a step of applying a solution containing a crosslinking agent), and then further dried at 80 ° C. for 10 minutes. (Drying step). As a result, a color material receiving layer having a dry film thickness of 32 μm was formed on the support, and an image receiving sheet of the present invention was produced. <Composition of Borax-containing solution> Borax 6% 25 parts Surfactant 10% aqueous solution 2 parts (F-144D Dainippon Ink and Chemicals, Inc.) Ion exchange water 68 3 parts Polyallylamine 20% aqueous solution (mordanting agent)
3 parts (molecular weight: 5000) Polyfix 700: 1.7 parts (manufactured by Showa Polymer Co., Ltd.)

Table 1 shows the glossiness, apparent glossiness and smoothness of the obtained ink-jet image-receiving sheet. For the evaluation of the apparent glossiness and smoothness, a relative sensory evaluation was performed in comparison with a conventional high-grade paper for inkjet. ○ Very good. △ Good. × Inferior.

Examples 2 to 5 Commercially available coated paper, cast coated paper and art paper shown in Table 1 (JIS P of the image forming side of these papers)
The glossiness specified by 8142 is indicated as “base glossiness” in Table 1) as a base paper, and a corona discharge treatment is performed on the surface of the base paper opposite to the image forming side, and the density is 0.980 g / g.
cm ³ of polyethylene was coated with a melt extruder so that the film thickness became 15 μm. Next, after a corona discharge treatment was applied to the image forming side of the base paper, the following polyethylene resin composition was coated with a melt extruder so as to have a film thickness shown in Table 1. <Polyethylene resin composition> LDPE (density 0.920 g / cm ³ ) 83.88% TiO ₂ (anatase type) 15.8% bluing agent (ultramarine) 0.3% fluorescent whitening agent 0.02% Table 1 shows the average roughness of the center plane (SRa value) when measured under the conditions of a cutoff of 6 to 7 mm of the resin film.
Shown in The resulting support for image materials had good glossiness and smoothness. Further, a colorant receiving layer was formed in the same manner as in Example 1 using the obtained support for an image material, and an image receiving sheet for inkjet was produced. Table 1 shows the glossiness, the apparent glossiness, and the smoothness of the inkjet image-receiving sheet.

Comparative Examples 1 to 3 Commercially available high-quality paper, information recording paper and coated paper shown in Table 1 (JIS P8142 of the image forming side of these papers)
The image material support was obtained in the same manner as in Examples 2 to 5, except that the glossiness specified in (1) is indicated as “base paper glossiness” in Table 1) as a base paper. Table 1 shows the average roughness of the center plane (SRa value) when the polyethylene resin film on the image forming side of the support was measured under the condition of a cutoff of 6 to 7 mm. Also, an image receiving sheet for ink jet was produced in the same manner. Table 1 shows the glossiness, the apparent glossiness, and the smoothness of the inkjet image-receiving sheet.

[0022]

[Table 1]

Example 6 In this example, when a heat-sensitive recording material was produced using the support for an image material of the present invention, the glossiness, apparent glossiness and smoothness of the heat-sensitive recording material after image formation were evaluated. Is shown. (1) Preparation of coating solution for heat-sensitive recording layer <Preparation of microcapsule solution A> The following compound (A) having a maximum absorption wavelength at 420 nm as a diazonium compound:
-1) 2.2 parts of compound (A-2) and 2.2 parts of compound (A-2) were dissolved in 16.4 parts of ethyl acetate, and 7.3 parts of isopropyl biphenyl, which is a high boiling point solvent, and tricresyl phosphate 2.5 And 0.4 part of the acylphosphine oxide compound (19) were added, and the mixture was heated and uniformly mixed.

[0024]

Embedded image

In the above mixture, as a capsule wall material, xylylene diisocyanate / trimethylolpropane adduct (takenate D110N, 75% by weight ethyl acetate solution,
4.5 parts by Takeda Pharmaceutical Co., Ltd. and Japanese Patent Application No. 5-233536
Of xylylene diisocyanate / bisphenol A adduct (30 parts by weight, ethyl acetate solution) synthesized according to the description in JP-A-2000-205, and stirred uniformly.

Separately, 77 parts of a 6% by weight aqueous gelatin solution to which 0.96 parts of ScrapA G-8 (manufactured by Nippon Seika Co., Ltd.) was added was prepared, and a mixed solution (solution) of the diazonium compound was added. The mixture was emulsified and dispersed with a homogenizer.
After adding 20 parts of water to the obtained emulsion and homogenizing it,
While stirring for 3 hours. Thereafter, the liquid temperature was lowered to 35 ° C., 6.5 parts of an ion exchange resin Amberlite IRA68 (manufactured by Organo) and 13 parts of Amberlite IRC50 (manufactured by Organo) were added, and the mixture was further stirred for 1 hour. After filtering the ion exchange resin, 0.4 part of a 1% by weight aqueous hydroquinone solution was added to 10 parts of the capsule liquid and stirred. Thus, a capsule solution A of the diazonium compound was obtained. The average particle size of the capsule was 0.8 μm.

<Preparation of coupler emulsion> Ethyl acetate 1
A solution II obtained by dissolving 3.0 parts of the coupler represented by the following formula, 3.0 parts of triphenylguanidine, 0.5 part of tricresyl phosphate and 0.24 part of maleic acid diethyl ester in 0.5 part was obtained. Was.

[0028]

Embedded image

Next, 49 parts of a 15% by weight aqueous solution of lime-processed gelatin, 9.5 parts of a 10% aqueous solution of sodium dodecylbenzenesulfonate, and 35 parts of water were uniformly mixed at 40 ° C.
Solution II was added, and the mixture was added at 40 ° C. and 1000 using a homogenizer.
0r. p. m. For 10 minutes. The obtained emulsion was stirred at 40 ° C. for 2 hours to remove ethyl acetate, and then the weight of the evaporated ethyl acetate and water was supplemented with water to obtain a coupler emulsion.

<Preparation of Coating Solution for Thermosensitive Recording Layer> 3.6 parts each of microcapsule solution A, microcapsule solution B and microcapsule solution C, 10 parts of water, coupler emulsion B1
Five parts were uniformly mixed to obtain a thermosensitive recording layer coating solution.

(2) Preparation of protective layer coating solution Itaconic acid-modified polyvinyl alcohol (KL-318;
A mixture of 100 parts of a 6% aqueous solution (trade name, manufactured by Kuraray Co., Ltd.) and 10 parts of a dispersion of 30% epoxy-modified polyamide (FL-71; trade name, manufactured by Toho Chemical Co., Ltd.) was mixed with 40% zinc stearate. 15 parts (Hydrin Z; trade name, manufactured by Chukyo Yushi Co., Ltd.) were uniformly mixed to obtain a protective layer coating liquid.

(3) Preparation of Thermosensitive Recording Material A high quality paper having a gloss on the image forming side of 66% was used as a base paper of a support for the thermosensitive recording material. The surface of the base paper opposite to the image forming side is subjected to a corona discharge treatment to have a density of 0.980 g.
/ Cm ³ of polyethylene was coated with a melt extruder so that the film thickness became 15 μm. Next, after subjecting the image forming side of the base paper to corona discharge treatment, the same polyethylene resin composition as used in Examples 2 to 5 was coated with a melt extruder so as to have a film thickness of 30 μm. did. Of the polyethylene resin film on the image forming side,
The center plane average roughness (SRa value) measured under the conditions of a cutoff of 6 to 7 mm was 0.48. On the polyethylene film, a heat-sensitive recording layer coating solution and a protective layer coating solution were sequentially coated and dried at 50 ° C. with a wire bar,
The desired heat-sensitive recording material was obtained. The amount of application as solid content is
^They were 15.0 g / m ² and 1.2 g / m ² , respectively.

<Evaluation of glossiness, apparent glossiness and smoothness of heat-sensitive recording material after recording> The obtained heat-sensitive recording material was subjected to image recording and fixing under the following conditions, and the glossiness in the image area and the appearance were evaluated. Was evaluated for glossiness and smoothness. The apparatus used for recording is a thermal head KST type (manufactured by Kyocera Corporation). (Image Recording and Fixing Conditions) The power applied to the thermal head and the pulse width were adjusted so that the recording energy per unit area was 35 mJ / mm ^2, and printing was performed on the thermosensitive recording material to record a yellow image. . Thereafter, the heat-sensitive recording material was irradiated and fixed for 10 seconds using an ultraviolet lamp having an emission center wavelength of 420 nm and an output of 40 W. The glossiness of the image portion of the heat-sensitive recording material was 20%, and the apparent glossiness and smoothness were both very good.

[0034]

In the present invention, the glossiness of the image forming side of the base paper and the average roughness of the center surface of the resin coating on the image forming side of the image material support (measured at a cutoff of 6 to 7 mm) are measured. By setting the specific range, it is possible to obtain an image material support having high apparent glossiness and smoothness, and to provide an image forming layer such as a color material image receiving layer on the image forming side of such an image material support. Is provided, an image forming layer having excellent glossiness and smoothness can be obtained. Further, the appearance of the image portion after forming an image on the image forming layer is excellent in glossiness and smoothness.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G03C 1/79 B41M 5/26 101H F term (Reference) 2H023 FA03 FA04 FA12 2H026 EE03 EE05 FF11 FF17 GG05 2H086 BA21 BA24 BA41 BA44 2H111 CA02 CA05 CA13 CA23 CA30 CA41 4F100 AK01B AK01C AK05 AK06 BA03 BA10B BA10C DD07 DG10A EG001 EH231 EH232 EJ551 EJ641 GB90 JK15 JN21 YY00

Claims (3)

[Claims] 1. A glossiness defined by JIS P8142 on an image material support on which both sides of a paper are coated with a resin capable of forming a film and on the side of the paper on which an image is formed. Is not less than 20%, and the center surface average roughness (SR
(a value) is 0.75 μm or less when measured under conditions of a cutoff of 6 to 7 mm. 2. The support for an image material according to claim 1, wherein the glossiness is 40% or more. 3. The image material support according to claim 1, wherein the paper having a surface glossiness of 20% or more specified in JIS P8142 is a coated paper.