JPH0911642A - Photographic paper - Google Patents

Abstract

(57) [Summary] [Purpose] Occurrence of blocking and weather resistance of the image when the dye receiving layer of the sublimation type thermal transfer recording photographic paper is formed from an acrylic resin capable of realizing good image quality and image storability. Prevents the occurrence of microcracking without lowering the light resistance (light resistance). [Structure] In a photographic printing paper 1 composed of a substrate 2 and a dye receiving layer 3 formed thereon, the dye receiving layer 3 is formed by dispersing silicone rubber fine particles in an acrylic resin.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printing paper suitable for sublimation type thermal transfer recording. More specifically, it relates to a photographic printing paper having a dye receiving layer capable of forming a transferred image having excellent storage characteristics such as sebum resistance, plasticizer resistance, blocking resistance and light resistance.

[0002]

2. Description of the Related Art An ink ribbon having an ink layer made of a sublimable or heat-diffusible dye and a printing paper having a dye receiving layer are superposed on each other, and the ink layer of the ink ribbon is subjected to image information by a thermal head or the like. There is known a sublimation type thermal transfer recording method in which an image is formed by heating by heating and transferring a dye from an ink layer to a dye receiving layer of a printing paper. This method has attracted attention as a method of hard copying a video image because it can form a continuous-tone full-color image.

FIG. 1 is a sectional view of a general photographic paper 1 used for sublimation type thermal transfer recording. As shown in the figure,
The photographic printing paper 1 has a laminated structure of a sheet-shaped substrate 2 and a dye receiving layer 3. Here, the dye receiving layer 3 is a layer that receives the dye transferred from the ink ribbon during thermal transfer recording and holds the image formed by the dye. Such a dye receiving layer 3 is conventionally formed of a dyeing resin such as polyester, cellulose ester, polycarbonate, polyvinyl chloride or the like.

By the way, the photographic paper as shown in FIG. 1 has recently been required to have the following properties so as to be compatible with high-speed printers: (i) High sensitivity and dyeability High, high density, capable of forming a glossy and clear image, (ii) good storage stability of the image, that is, (a) excellent fingerprint resistance and sebum resistance, specifically, When the image comes into contact with a part of the human body such as hands and fingers, the dye forming the image does not cause aggregation or discoloration, (b) excellent plasticizer resistance, specifically, When the image comes in contact with a plastic eraser containing a plasticizer or its eraser, the dye forming the image does not aggregate or discolor, and (c) the image does not discolor or discolor when exposed to light. Have high light resistance, and (d) excellent dark fade resistance.

However, the conventional dye receiving layer formed of a dyeable resin has a problem that it is not possible to sufficiently meet these requirements.

Therefore, the applicant of the present invention has proposed a photographic paper having a dye receiving layer formed of an acrylic resin such as phenoxyethyl methacrylate as a photographic paper that meets these requirements (Japanese Patent Application No. 7-59844). ). According to this printing paper, it is possible to obtain a transferred image having good quality and storability.

[0007]

By the way, it is desired that the surface of the dye receiving layer of the photographic printing paper is flat in order to effectively transfer the dye from the ink layer of the ink ribbon. In this case, the layer thickness of the dye receiving layer is such that the surface roughness of the base material of the printing paper is about 1 to 3 μm, so that the influence of the surface roughness is eliminated and the flatness of the surface of the dye receiving layer is ensured. Generally, it is set to about 5 to 8 μm.

However, when the dye receiving layer having such a layer thickness is formed of an acrylic resin, the acrylic resin is relatively less flexible than the polyester resin, so that the photographic paper is bent extremely. A large number of microcracks are generated in the dye receiving layer, which causes a problem of deterioration of image quality and deterioration of image storability.

To solve this problem, it is conceivable to add a plasticizer such as dioctyl phthalate ester to the dye receiving layer to improve the flexibility of the dye receiving layer. However, in this case, when a sufficient amount of a plasticizer is added to suppress the occurrence of cracking, the glass transition point of the dye receiving layer is excessively lowered, and the plasticizer excessively bleeds to the surface. However, there is a problem that blocking occurs.

Alternatively, it is considered that the dye receiving layer contains a butadiene rubber which is widely used for improving the toughness of plastic materials. However, since the carbon-carbon double bond is present in the butadiene polymer unit of the butadiene rubber, the weather resistance (for example, light resistance) of the dye receiving layer itself and the transferred image becomes insufficient, and the transferred image has long-term storage stability. There is concern that problems will arise.

The present invention is intended to solve the above-mentioned problems of the prior art, and it is possible to prevent blocking when a dye receiving layer is formed from an acrylic resin which can realize good image quality and image storability. Occurrence and weather resistance of the image (for example,
The purpose of the present invention is to prevent cracking from occurring in the dye-receptive layer without lowering the light resistance.

[0012]

DISCLOSURE OF THE INVENTION The present inventors have found that when silicone rubber fine particles are dispersed in a dye receiving layer made of an acrylic resin, the occurrence of blocking or image formation is prevented without impairing the desirable characteristics of the acrylic resin. The present inventors have found that it is possible to prevent the occurrence of cracking in the dye receiving layer without causing deterioration of weather resistance (for example, light resistance), and have completed the present invention.

That is, the present invention provides a photographic printing paper comprising a substrate and a dye receiving layer, wherein the dye receiving layer comprises acrylic resin and silicone rubber fine particles. is there.

The present invention will be described in detail below. The photographic printing paper 1 of the present invention is constructed similarly to the photographic printing paper shown in FIG. 1, and basically comprises a sheet-shaped base material 2 and a dye receiving layer 3 formed thereon.

As described above, the dye receiving layer 3 has a structure in which the silicone rubber fine particles are dispersed in the acrylic resin. Here, the silicone rubber does not have a reactive double bond and exhibits rubber elasticity. Therefore, by blending a silicone-based rubber in the dye receiving layer, the weather resistance (for example, light resistance) of the transferred image is not lowered, and cracking in the dye receiving layer 3 is prevented when the photographic printing paper 1 is bent extremely. Occurrence can be suppressed. Further, by dispersing such silicone rubber as fine particles in the acrylic resin, the proportion of the acrylic resin in the cross section of the dye receiving layer 3 becomes small, and the silicone rubber fine particles absorb stress to absorb the dye. The cracking of the layer 3 can be further suppressed.

The acrylic resin used in the present invention includes phenyl acrylate, phenoxyethyl acrylate, cyclohexyl acrylate and methyl acrylate.
Acrylic acid ester such as ethyl acrylate, butyl acrylate, or the like, or phenyl methacrylate, phenoxyethyl methacrylate, methyl methacrylate, isobornyl methacrylate, cyclohexyl methacrylate, ethyl. Methacrylate, allylmethacrylate,
Mention may be made of polymers containing polymerized units derived from methacrylic acid esters such as hydroxyethyl methacrylate, which may be a single homopolymer,
It may be a copolymer of a plurality of these. Or,
These acrylic acid esters or methacrylic acid esters and other monomers or oligomers copolymerizable with them,
For example, it may be a vinyl compound such as vinyl chloride, vinyl acetate, styrene, or vinyl benzoate, or a copolymer with an ester oligomer, a urethane oligomer, or the like.

If the weight average molecular weight of the acrylic resin is too small, the coating properties are not sufficient, and if it is too large, the coatability deteriorates, so 50,000 to 100.
About 10,000 is preferable.

The method for producing the acrylic resin is not particularly limited, and it can be produced by a known suspension polymerization method, bulk polymerization method, solution polymerization method, emulsion polymerization method or the like.

The silicone rubber fine particles used in the present invention include siloxane compounds as polymerized units,
It is preferable to use polymer fine particles containing methyl siloxane or phenyl siloxane in a proportion of 1% by weight or more. In this case, a siloxane compound,
Fine particles of copolymers with acrylic acid esters, methacrylic acid esters, vinyl compounds and the like can also be used.

The molecular weight of the silicone rubber fine particles is not particularly limited as long as the particle shape can be maintained during formation of the dye receiving layer 3 and during use of photographic paper. If the average particle size of the silicone rubber fine particles is too large, the surface flatness of the dye receiving layer 3 is lowered and it becomes difficult to transfer a good image. Therefore, the average particle size is preferably 2 μm or less, and more preferably 1 μm or less. .

If the content of such silicone rubber fine particles in the dye receiving layer 3 is too small, the effect of the present invention will not be sufficiently obtained, and if it is too large, the high storage property of the image based on the acrylic resin will be impaired. Since it shows a tendency, it is preferably 10 to 50% by weight, more preferably 10 to 20% by weight.

The silicone rubber fine particles can be produced by known suspension polymerization, emulsion polymerization or the like.

The dye receiving layer 3 of the photographic printing paper of the present invention may contain a dyeing property improving agent and a storability improving agent, if necessary, in addition to the above acrylic resin and silicone rubber fine particles. . Examples of such a dyeing property improving agent or a preserving property improving agent include various ester compounds (polyhydric phenol ester, polyhydric alcohol ester, phthalic acid ester, phosphoric acid ester, etc.) generally used as a plasticizer, , Polyester, polycarbonate,
Various resins such as polyacrylic acid ester and polyvinyl chloride resin can be used.

When such a dyeing property improving agent or a preserving property improving agent is contained in the dye receiving layer 3 together with the above-mentioned acrylic resin and silicone rubber fine particles, the amount thereof should not exceed 50% by weight of the dye receiving layer. Preferably.

Further, various additives can be added to the dye receiving layer 3 of the photographic printing paper of the present invention. For example, in order to improve the whiteness of the dye receiving layer 3 to improve the sharpness of the image, to give the image surface writability, and to prevent retransfer of the image formed by thermal transfer, fluorescent whitening is performed. Agents (fluorescent dyes) and white pigments can be included. As such a fluorescent whitening agent, a commercially available product such as Ubitex OB manufactured by Ciba-Geigy can be used. Further, as the white pigment, titanium oxide, zinc oxide, kaolin, clay, calcium carbonate, fine powder silica and the like can be contained. These may be used alone or in combination of two or more.

Further, in order to further improve the weather resistance of the image, the dye receiving layer 3 may contain one or more kinds of ultraviolet absorbers, light stabilizers, antioxidants, surface modifiers and the like. it can.

Further, the dye receiving layer 3 may contain a releasing agent in order to improve the releasing property from the ink ribbon at the time of thermal transfer. As the release agent, solid waxes such as polyethylene wax, amide wax, and Teflon powder, fluorine-based and phosphate-based surfactants, silicone oil, and high melting point silicone wax can be used. Among them, it is preferable to use silicone oil from the viewpoints of mold release properties and durability. in this case,
As silicone oil, oily ones also react (harden)
The type can also be appropriately selected and used. Here, as the reaction (curing) type silicone oil, a reaction cured product of alcohol-modified silicone oil and isocyanate, epoxy-modified silicone oil (epoxy / polyether-modified silicone oil) and carboxy-modified silicone oil (carboxy / polyether-modified silicone) It is possible to use a reaction cured product with an oil, a reaction cured product of an amino-modified silicone oil (amino-polyether-modified silicone oil) and a carboxy-modified silicone oil (carboxy-polyether-modified silicone oil), and the like.

Further, the dye receiving layer 3 may contain various curing agents in order to improve its mechanical strength and the like. As such a curing agent, for example, an epoxy curing agent, an isocyanate curing agent or the like can be used, and among them, a non-yellowing type polyfunctional isocyanate compound is preferable. Examples of such polyfunctional isocyanate compounds include aliphatic polyisocyanates such as hexamethylene diisocyanate (HDI) and biuret, and aromatic polyisocyanates such as toluene diisocyanate (TDI) and xylene diisocyanate (XDI). . These may be used alone or in combination of two or more.

In addition, the dye receiving layer 3 may contain an antistatic agent in order to suppress the generation of static electricity during the process of printing photographic paper or during running in the printer. As the antistatic agent, a cationic surfactant (4th
Use of various surfactants such as primary ammonium salt, polyamine, etc.), anionic surfactant (alkylbenzene sulfonate, sodium alkyl sulfate ester, etc.), zwitterionic surfactant, nonionic surfactant, etc. You can Such an antistatic agent may be contained in the dye receiving layer 3 or may be applied to the surface of the dye receiving layer 3 by coating or the like.

The base material 2 of the photographic paper of the present invention may have the same structure as that of the base material of the conventional photographic paper.
Paper such as high-quality paper, coated paper, synthetic paper, various plastic sheets, or composite sheets of these can be used.

The surface of the substrate 2 opposite to the dye receiving layer 3 is made of a silicone resin or the like in order to improve the running property of the printing paper in the printer and to prevent the printing paper from being double fed. It is preferable to form a back coat layer made of a known material.

The photographic printing paper 1 of the present invention can be manufactured by a conventional method, and a coating liquid comprising an acrylic resin, silicone rubber fine particles and, if necessary, other components on one surface of the substrate 2. It can be manufactured by applying to the substrate 2 and drying. Here, there is no particular limitation on the method for preparing the coating liquid containing the acrylic resin and the silicone rubber fine particles. For example, an acrylic resin dissolved in an organic solvent and silicone rubber fine particles dispersed in an organic solvent may be mixed, or both may be dispersed in an aqueous solvent. Rubber particles may be mixed.

The method of forming an image on the photographic printing paper of the present invention is not particularly limited, and for example, sublimation type thermal transfer recording can be performed by using a commercially available video printer or the like using an ink ribbon for sublimation type thermal transfer recording.

[0034]

In the photographic paper of the present invention, the dye receiving layer is composed of acrylic resin and silicone rubber fine particles.
Therefore, cracking in the dye receiving layer is prevented, and the storage stability of the transferred image formed in the dye receiving layer, for example, sebum resistance, light resistance, plasticizer resistance, etc. It is possible to maintain the same level of storage stability as that obtained in the case of a dye receiving layer mainly composed of.

[0035]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below based on embodiments.

Examples 1 to 7 and Comparative Examples 1 to 7 As a sheet-shaped substrate, 150 μm thick synthetic paper (FPG-150 manufactured by Oji Yuka Co., Ltd.) was prepared. On the other hand, a coating material for forming a dye receiving layer containing the components shown in Tables 1 and 2 was prepared. At this time, the total solid content was made to be a 20% solution with a 2-butanone / toluene (1/1 weight ratio) mixed solvent.

The obtained coating material was applied to the surface of the substrate with a wire bar so that the dry film thickness was 5 to 6 μm, dried with a warm air dryer at 120 ° C. for 1 minute, and further at 50 ° C. for 4 minutes.
The photographic papers of Examples and Comparative Examples were prepared by aging for 8 hours.

The components used in Tables 1 and 2 are as follows. * Acrylic resin * 1: Phenoxyethyl methacrylate / hydroxyethyl methacrylate / styrene (90
/ 5/5) copolymer (Mw = 200,000) * Silicone oil * 2: SF8427, manufactured by Toray Dow Corning * Isocyanate compound * 3: Takenate D110N,
Takeda Pharmaceutical Co., Ltd. * Silicon rubber particles * 4: Metaprene S2001
(Average particle size 0.3 μm (measured by helium-neon laser light scattering method), manufactured by Mitsubishi Rayon Co. * Butadiene rubber fine particles * 5: MBR rubber (average particle size 0.3 μm (helium-neon laser light scattering method) Made by Japan Synthetic Rubber Co., Ltd. * Plasticizer * 6: Dioctyl phthalate, Wako Pure Chemical Industries, Ltd.

[0039]

[Table 1] (parts by weight) Example Ingredient name 1 2 3 4 5 6 7 Acrylic resin * 1 100 ← ← ← ← ← ← ← Silicone oil * 2 5 ← ← ← ← ← ← Isocyanate compound * 3 5 ← ← ← ← ← ← Silicone rubber particles * 4 5 10 20 30 40 50 60

[0040]

[Table 2] (Parts by weight) Comparative example Ingredient name 1 2 3 4 5 6 7 Acrylic resin * 1 100 ← ← ← ← ← ← ← Silicone oil * 2 5 ← ← ← ← ← ← Isocyanate compound * 3 5 ← ← ← ← ← ← Fine particles of butadiene rubber * 5 − − − − 5 10 20 30 Plasticizer * 6 − 20 40 − − − −

(Evaluation) With respect to the printing papers of Examples and Comparative Examples, (1) transfer sensitivity, (2) blocking resistance,
(3) Light resistance, (4) Sebum resistance, and (5) Cracking resistance were tested and evaluated as follows. The glass transition point (Tg (° C.)) of the dye receiving layer was measured at a temperature rising rate of 20 ° C./min using DSC-7 manufactured by Perkin Elmer. The results are shown in Tables 3 and 4.

(1) Transfer Sensitivity Sublimation type thermal transfer ink ribbon (U
The highest density (OD) of the obtained image was obtained by performing black step printing with a color video printer (UP-D7000 manufactured by Sony Corporation) using PC-7010, manufactured by Sony Corporation.
Max) was measured using a Macbeth reflection densitometer (TR-924), and the transfer sensitivity was evaluated according to the following evaluation criteria.

Transfer Sensitivity Evaluation Criteria Rank State A: ODmax> = 2.4 O: 2.4>ODmax> = 2.2 B: 2.2>ODmax> = 1.8 x: 1.8> ODmax

(2) Blocking resistance In the process of forming photographic paper, a dye-receptive layer-forming coating material is applied on the surface of a sheet-like substrate and dried at 120 ° C. for 1 hour with a warm air dryer.
After drying for a minute, the coated surface and the back surface of the photographic paper substrate were overlapped, a weight (1 kg, bottom surface 5 × 5 cm) was placed thereon, and the mixture was left at 50 ° C. for 48 hours. After that, the photographic printing papers were peeled off and the blocking resistance was evaluated according to the following evaluation criteria.

Blocking Resistance Evaluation Criteria Rank State ○: When no cling is observed (no blocking) Δ: When cling is partially observed ×: When cling is entirely observed

(3) Lightfastness An image was formed on photographic paper in the same manner as in the above (1), and the image was measured with a xenon fade meter at 90,000 kJ / m ² (30
Irradiation at 65 ° C. and 65% RH. The optical densities before and after this irradiation were measured using a Macbeth reflection densitometer, the dye residual ratio was calculated according to the following formula (1), and the light resistance was evaluated according to the following evaluation criteria based on the dye residual ratio.

[0047]

## EQU1 ## Dye residual ratio (%) = (optical density after irradiation / optical density before irradiation) × 100 (1)

Light Resistance Evaluation Standard Rank State ⊚: Dye residual rate ＞ = 80% ◯: 80% ＞ Dye residual rate ＞ = 65% △ ： 65% ＞ Dye residual rate ＞ ＝ 50% × ： 50% ＞ Dye residual rate

(4) Sebum resistance An image was formed on photographic paper in the same manner as in the transfer sensitivity test of (1) above, and the image was immersed in artificial sebum at 35 ° C. for 2 minutes,
After taking out, the artificial sebum on the surface was wiped off. Then, from the optical densities before and after this treatment, the dye residual ratio was obtained by measuring in the same manner as in the light resistance test of (3), and the sebum resistance was evaluated according to the same evaluation criteria.

(5) Cracking resistance The formed printing paper was bent so that the surface of the dye-receiving layer became a mountain, and the vicinity of the fold was visually observed at that time, and the cracking resistance was evaluated according to the following evaluation criteria. did.

Cracking resistance evaluation standard rank Condition ○: No cracks were observed at all △: Microcracks were observed ×: Large cracks were observed

[0052]

[Table 3] Examples Evaluation items 1 2 3 4 5 6 7 (1) Transfer sensitivity ◎ ◎ ◎ ◎ ◎ ◎ ○ △ (2) Blocking resistance ○ ○ ○ ○ ○ ○ ○ Glass transition point (Tg (° C)) 53 53 54 54 54 54 52 (3) Light resistance ○ ○ ○ ○ ○ ○ ○ (4) Sebum resistance ◎ ◎ ◎ ◎ ◎ ◎ ○ △ △ (5) Cracking resistance △ ○ ○ ○ ○ ○ ○ ○

[0053]

[Table 4] Comparative example Evaluation items 1 2 3 4 5 6 7 (1) Transfer sensitivity ◎ ◎ ◎ ◎ ◎ ○ ○ △ △ (2) Blocking resistance ○ △ × ○ ○ ○ ○ Glass transition point (Tg (° C)) 53 38 21 52 52 54 53 (3) Light resistance ○ ○ ○ × × × × (4) Sebum resistance ◎ ◎ ○ ○ △ △ △ (5) Cracking resistance × × ○ △ ○ ○ ○

From the results shown in Table 3, the photographic printing papers of Examples 1 to 7 showed excellent results in all evaluation items. Regarding the added amount of the silicone rubber fine particles, it can be seen that the photographic printing paper of Example 1, which has the smallest amount, is slightly inferior in cracking resistance to the printing papers of the other Examples. Further, it can be seen that the photographic paper of Example 7, which has the largest number, is inferior to the photographic papers of the other Examples in terms of transfer sensitivity and sebum resistance. Therefore, the preferable addition amount of the silicone rubber fine particles is at least in the range of Examples 2 to 6, that is, 10 to 10.
It can be seen that it is 50% by weight.

On the other hand, the photographic printing paper of Comparative Example 1 is good in image storability because the dye receiving layer is composed of an acrylic resin, but since it does not use silicone rubber fine particles, it is resistant. The cracking property was insufficient. Comparative Examples 2 and 3 are examples in which a cracking resistance is improved by adding a plasticizer in place of the silicone rubber fine particles, but the amount of the plasticizer required to realize sufficient cracking resistance. As shown in Comparative Example 3, Tg of the dye-receptive layer was lowered and the blocking resistance was deteriorated. The photographic printing papers of Comparative Examples 4 to 7 are examples in which butadiene-based rubber fine particles are added in place of the silicone-based rubber fine particles to improve the cracking resistance, but the light resistance is greatly deteriorated. I understand.

[0056]

According to the photographic printing paper of the present invention, it is possible to form an image with high sensitivity and obtain an image excellent in storability. Further, the cracking resistance of the dye receiving layer is improved.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a general photographic paper.

[Explanation of symbols]

 1 photographic paper 2 substrate 3 dye receiving layer

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Haruichi Yamamoto 3-25-3 Hasune, Itabashi-ku, Tokyo Fujikura Kasei Co., Ltd. (72) Masataka Mizoguchi 3-25-3 Hasune, Itabashi-ku, Tokyo Fujikura Fujikura Kasei Co., Ltd.

Claims (5)

[Claims] 1. A printing paper comprising a substrate and a dye-receiving layer formed thereon, wherein the dye-receiving layer contains an acrylic resin and silicone rubber fine particles. 2. The printing paper according to claim 1, wherein the silicone rubber fine particles are fine particles of a polymer containing methylsiloxane or phenylsiloxane as a polymerized unit. 3. The content of polymerized units of methyl siloxane or phenyl siloxane in the silicone rubber fine particles is 1
The photographic printing paper according to claim 2, wherein the photographic printing paper has a weight% or more. 4. The photographic paper according to claim 1, wherein the content of the silicone rubber fine particles in the dye receiving layer is 10 to 50% by weight. 5. The average particle size of the silicone rubber fine particles is 2
The photographic printing paper according to any one of claims 1 to 4, which has a thickness of not more than μm.