JPH115858A - Production of polyester supporter for photographic printing paper - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject supporter that can develop the excellent adhesion to the photographic image-forming layer by coating white polyester film having specific physical properties with a coating solution containing specific components and drying the coated film. SOLUTION: (A) A coating solution containing (i) a water-based polyurethane and (ii) a water-based epoxy group-bearing organic compound at a ratio of 10/90-80/20 on the dry basis is coated on (B) at least one face of a white polyester film with a opacity degree of >=0.3 and the b value of <2.0 and dried to give the objective supporter. The component A is included in the dried coated layer more than 60% based on the total weight of the components (i) and (ii) on the dry basis. The component B contains a white pigment and has an apparent density of 0.6-1.2 g/cm<3> containing a number of fine closed cells whereby the objective supporter for photographic printing paper having good adhesion to the photographic image-forming layer can be readily provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a process for producing a support for polyester photographic printing paper, and more particularly, to a method for forming an undercoat layer having excellent adhesion to a photographic image forming layer provided on the support. The present invention relates to a method for producing a white polyester film having the same.

[0002]

2. Description of the Related Art As a support on which a photographic image forming layer is provided as photographic printing paper, paper has been used for many years. In this application, paper is a material having excellent characteristics in terms of appearance, feel, mechanical properties, price, and the like. On the other hand, paper has the characteristic of easily absorbing and impregnating water, and it is used after being subjected to various water-resistant treatments.However, it is difficult to completely prevent absorption from the edges, and photographic processing There remains a problem that an image becomes yellowed with the elapse of time due to the remaining developer component. In addition to the water resistance, a white plastic film called synthetic paper is used in order to obtain mechanical properties, high-grade appearance, and image quality that are not available in paper.

[0003] One example of synthetic paper is a white polyester film. Polyester films are widely used because of their well-balanced properties, and can also be used for photographic printing paper. However, polyester films typified by polyethylene terephthalate and polyethylene-2,6-naphthalate have poor surface activity and adhere to a photographic image forming layer provided by overcoating a photographic emulsion mainly containing gelatin as a main component of a binder. It also has the disadvantage of being extremely poor in sex.

The adhesion to the photographic image forming layer must be exerted not only when the finished photograph is dry but also in a wet state during photographic processing represented by development processing. For this reason, when a polyester film is used as a support, there is often employed a technique in which a certain kind of polymer layer is provided on the film before the photographic image forming layer is provided to form an easily adhesive layer.

Specifically, it is known to provide a layer such as a polyester copolymer, a vinylidene chloride copolymer, a mixture of gelatin and a hydrophilic vinyl or acrylic copolymer, or a carboxy-modified polyethylene. Further, the polyester film may be subjected to a pretreatment such as a corona discharge treatment before providing the polymer layer.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide a polyester-based photographic printing paper support having excellent adhesion to a photographic image forming layer. Specifically, an object of the present invention is to provide a white polyester film provided with a photographic image forming layer and an undercoat layer exhibiting excellent adhesiveness when dry and wet.

[0007]

Means for Solving the Problems As a result of intensive studies in view of the above problems, the present inventor has found that a photographic printing paper support having excellent characteristics can be easily provided by employing a specific method. Thus, the present invention has been completed.
That is, the gist of the present invention is to provide an aqueous polyurethane and an aqueous epoxy group-containing compound in a dry weight ratio of 10/9.
A coating solution containing the coating solution at a ratio of 0 to 80/20 is concealed (O
D) The method for producing a support for a polyester-based photographic printing paper, characterized in that it is applied to at least one side of a white polyester film having a value of 0.3 or more and a value of b less than 2.0 and dried.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail.
As the polyester of the polyester film referred to in the present invention, typically, for example, polyethylene terephthalate (PET) in which at least 80 mol% of the structural units are ethylene terephthalate, and at least 80 mol% of the structural units are ethylene-2,6-naphthalate Polyethylene-2,6-
In addition to naphthalate (PEN), poly-1,4-cyclohexane dimethylene terephthalate in which 80 mol% or more of the structural unit is 1,4-cyclohexane dimethylene terephthalate, polyethylene isophthalate, polybutylene terephthalate, and the like can also be used. .

[0009] The copolymerization components other than the above-mentioned predominant constituents include, for example, diol components such as diethylene glycol, propylene glycol, neopentyl glycol, polyethylene glycol and polytetramethylene glycol;
Isophthalic acid, 2,7-naphthalenedicarboxylic acid, 5-
Ester-forming derivatives such as sodium sulfoisophthalic acid, adipic acid, azelaic acid, sebacic acid and oxymonocarboxylic acid can be used. In addition, as a polyester, in addition to a homopolymer or a copolymer,
Small proportion blends with other resins can also be used.

The intrinsic viscosity [η] of the polyester is usually 0.45 or more, preferably 0.50 to 0.55.
1.0, more preferably in the range of 0.52 to 0.90. If the intrinsic viscosity is less than 0.45, there may be a problem that productivity during film production is reduced and mechanical strength of the film is reduced. On the other hand, it is preferable that the intrinsic viscosity does not exceed 1.0 from the viewpoint of melt extrusion stability of the polymer.

As the polyester film used in the present invention, a biaxially stretched polyester film is particularly preferable in view of the required characteristics of a photographic paper support. The method for producing the polyester film can be generally known methods,
The stretching method is performed by either simultaneous biaxial stretching or sequential biaxial stretching. However, sequential biaxial stretching is particularly often performed.

A more specific method for producing such a polyester film will be described. The polyester raw material is supplied to an extruder, melt-extruded at a temperature equal to or higher than the melting point of the raw material, and extruded as a molten sheet from a slit die. Next, the molten sheet is quenched and solidified on a rotary cooling drum so as to have a temperature equal to or lower than the glass transition point to obtain a substantially amorphous unstretched sheet. In this case, in order to improve the flatness of the sheet, it is preferable to increase the adhesion between the sheet and the rotary cooling drum.

The unstretched sheet obtained in this way is
Axial stretching is performed, and here, longitudinal and horizontal sequential biaxial stretching will be described as an example. Generally, an unstretched sheet is stretched (longitudinal stretching) in the longitudinal direction of the sheet by a group of rolls having a difference in peripheral speed. First, the sheet is preheated and maintained at a temperature equal to or higher than the glass transition point and equal to or lower than the melting point. In the case of PET, the temperature is preferably in the range of 70 to 150 ° C, and in the case of PEN, the temperature is preferably in the range of 115 to 170 ° C. Thereafter, the film is stretched to a total magnification of 2 to 10 times using the difference in peripheral speed of the roll. At this time, the stretching can be performed in one stage or two or more stages. Next, the film is stretched (transversely stretched) in the transverse direction, that is, in the direction perpendicular to the longitudinal direction. That is, once the obtained uniaxially oriented film is cooled to or below the glass transition point, or without cooling, the glass transition point or more, the temperature below the melting point, 80-150 ℃ if PET,
If it is PEN, the range of 120 ° C to 180 ° C is preferable,
The film is stretched 2 to 10 times while gripping the end of the film with a normal clip.

Here, an example of the order of longitudinal stretching and transverse stretching is shown, but the order may be reversed, and each stretching may be performed by dividing it into several times. Further, division may be performed, and a part of the division may be performed alternately. For example, a method of manufacturing a high-strength film by a re-stretching method corresponds to this. The biaxially oriented film thus obtained is usually heat-treated with elongation, limited shrinkage, or lengthening within 30%. The heat treatment time is preferably in the range of 1 second to 5 minutes. At this time, 10% within or after the heat treatment step.
Within, preferably within 5%, etc.
In particular, it can be employed to keep the heat shrinkage in the vertical direction in a suitable range. Although the heat treatment temperature depends on the stretching conditions, it is still higher than the glass transition point and lower than the melting point, for example, 170 to 250 ° C. for PET and 170 to 270 ° C. for PEN.
Is preferable.

If the heat treatment is long, for example, if the treatment time is long, or if the treatment temperature is high, the crystallization of the polyester will progress too much. In addition, when the coating layer is formed by in-line coating described later, the thermal decomposition of the resin forming the coating layer will occur. May occur. If the heat treatment is too small, the shrinkage of the film will increase. In any case, conditions are selected in which the properties of the finally obtained film meet the requirements as a support for photographic printing paper.

The thickness of the resulting photographic paper support is appropriately selected depending on the use as the photographic paper, but is preferably in the range of 15 to 350 μm. When the thickness is less than 15 μm, the rigidity as a support tends to be insufficient, and when the thickness is more than 350 μm, the weight of the material as the photographic paper tends to increase and the handling tends to be poor, which is disadvantageous in terms of cost. .

Further, such a film can be bonded to a base material such as paper and used with a desired thickness. By the way, an oriented and crystallized biaxially stretched polyester film that does not contain particles, fine bubbles, and the like generally has good transparency. However, in order to obtain a clear image as a photographic paper support, the film needs to be white.

Such a white polyester film is
It can be obtained by mixing and dispersing organic or inorganic or organic particles incompatible with the polyester before film formation. In addition, by containing particles, appropriate protrusions can be formed on the film, and the film can be provided with slipperiness, which can contribute to preventing scratches in the film and improving productivity.

Examples of such particles include calcium carbonate, calcium phosphate, silica, kaolin, talc,
Titanium dioxide, alumina, barium sulfate, calcium fluoride, lithium fluoride, zeolite, molybdenum sulfide,
Examples include crosslinked organic polymer particles, calcium oxalate, and precipitated particles formed during the polymerization of polyester.

A plurality of these particles can be used, and among them, it is preferable to use at least one of so-called white pigments in view of the whiteness of the film and the concealing property. Among the white pigments, calcium carbonate, barium sulfate, and titanium dioxide are particularly preferable, and it is preferable to use these particles as one type of particles to be used.

In the case of titanium dioxide, the crystal form may be either anatase or rutile type, but is more preferably anatase type titanium dioxide from the viewpoint of whiteness and weather resistance. Further, titanium dioxide particles whose surfaces are treated with an oxide and / or an organic compound such as aluminum, silicon, and zinc for the purpose of improving the dispersibility in polyester and the weather resistance may be used.

Usually, the average particle size of these particles is preferably 0.005 to 5.0 μm, more preferably 0.01 to 5.0 μm.
範 囲 3.0 μm. If the average particle size exceeds 5.0 μm, the film surface may be excessively roughened, and the quality of the photographic image may be degraded, or the particles may easily fall off the surface. Average particle size 0.005
If it is less than μm, the formation of projections by the particles is insufficient, so that the surface of the film is liable to be scratched or the handling property of the film tends to be reduced.

Further, the content of particles is
Usually, it is 0.3 to 30% by weight, preferably 0.5 to 20% by weight, more preferably 1.0 to 20.0% by weight.
When the particle content is less than 0.3% by weight, the whiteness of the film surface is insufficient, and the quality of a photographic image, particularly, contrast and sharpness tends to be insufficient. On the other hand, when the content of the particles exceeds 30.0% by weight, there is a possibility that the particles may easily fall off, or the particles may aggregate to form coarse projections.

In the production of polyester containing particles,
The particles may be added during the polyester synthesis reaction or may be added directly to the polyester. When it is added during the synthesis reaction, a method in which the particles are added as a slurry in which the particles are dispersed in ethylene glycol or the like at an arbitrary stage of polyester synthesis is preferable. On the other hand, when it is directly added to the polyester, it is used as dried particles or water or a compound having a boiling point of 2%.
As a slurry dispersed in an organic solvent at
A method of adding and mixing with polyester using a shaft kneading extruder is preferred. The particles to be added may be subjected to a process such as crushing, dispersion, classification, and filtration, if necessary, beforehand.

As a method of adjusting the content of particles, a master material containing particles at a high concentration is prepared in the above-described manner, and is diluted with a material substantially containing no particles at the time of film formation. A method of adjusting the particle content is effective. The film of the present invention is required to have high whiteness in terms of the quality of a photographic image. Therefore, it is preferable to contain a fluorescent whitening agent in addition to the above-mentioned particles, particularly a white pigment. Any type of fluorescent whitening agent may be used as long as it has a fluorescence peak at a wavelength of 400 to 700 nm, and preferred examples thereof include trade names “UPITEC OB, MD” (manufactured by Ciba Geigy) and “OB- 1 "(manufactured by Eastman) and" Mika White "(Nippon Kayaku-Mitsubishi Chemical). The content of the optical brightener in the polyester film is usually 50 to 5000 ppm, preferably 100 ppm.
３3000 ppm. Content of optical brightener is 50p
If it is less than pm, the whiteness tends to be insufficient. When the content of the optical brightener exceeds 5000 ppm,
There is a possibility that heat deterioration may occur in a kneading and mixing step of an extruder or the like when compounding a brightener into polyester.

In addition to the whitening of the film, fine bubbles can be contained in the film for the purpose of lowering the density of the film and imparting cushioning properties. The method for producing the polyester film containing microbubbles is not particularly limited, but from the viewpoint of cost and productivity, JP-A-63-168441 and JP-A-63-19393.
It is preferable to carry out the method described in Japanese Patent Publication No. 8 or the like or a method analogous thereto. That is, a method in which a polymer incompatible with the polyester is mixed with the polyester, extruded into a sheet shape, and then the obtained sheet is stretched in at least one axis direction to form a film.

Examples of the polymer incompatible with the polyester include polyolefins such as polyethylene, polypropylene, polymethylpentene, and polymethylbutene, polystyrene, polycarbonate, polyphenylene sulfide, and liquid crystal polyester. Polypropylene is preferred in terms of productivity.
The amount of the incompatible polymer is usually 5 to 40% by weight, preferably 5 to 40% by weight, based on the polymer constituting the film.
It is in the range of 30% by weight. Incompatible polymer content of 5
If the content is less than% by weight, the content of air bubbles tends to be small, and there is a possibility that weight reduction and cushioning properties may be insufficiently provided. On the other hand, when the content of the immiscible polymer exceeds 40% by weight, the film tends to be frequently broken during stretching, resulting in poor productivity. As described above, the incompatible polymer is blended with the polyester. In this method, it is necessary to further stretch the polymer in at least one axial direction. This not only provides the mechanical strength of the film as described above, but also allows sufficient closed cells to be contained only after the stretching step. This stretching method itself does not require a special operation, and is performed within the range of conditions for producing a normal polyester film.

When polypropylene is used as the incompatible polymer, at least 95 mol% or more, more preferably 9 mol% or more.
Preferably, at least 8 mol% is a crystalline polypropylene homopolymer having propylene units. When the polypropylene is amorphous, it is not preferable because when the amorphous polyester sheet is formed, the polypropylene bleeds out on the sheet surface and contaminates the surface of the cooling drum, the stretching roll, and the like. The propylene unit is 5 mol%
When the copolymerization is carried out beyond the range, formation of closed cells tends to be insufficient.

The melt flow index (MFI) of such polypropylene is usually in the range of 0.5 to 30 g / 10 minutes. If the MFI is less than 0.5 g / 10 min, the generated bubbles become large and breakage occurs during stretching. On the other hand, if the MFI exceeds 30 g / 10 min, the clip in the tenter may be detached or the density of the tenter may increase. In some cases, the uniformity of the target is poor, the density control becomes difficult, and the productivity may be deteriorated.

In the case of using the method of forming fine bubbles by blending an incompatible polymer as described above, the raw materials are controlled in order to control the size of the bubbles and bring the density and cushioning property of the film into desired ranges. It is preferable to include a surfactant therein. Examples of the surfactant include an anionic surfactant, a cationic surfactant, an amphoteric surfactant, and a nonionic surfactant. Among them, a nonionic surfactant, particularly a silicone surfactant is used. preferable. Examples of the silicone surfactant include an organopolysiloxane-polyoxyalkylene copolymer and an alkenylsiloxane having a polyoxyalkylene side chain. The content of the surfactant is preferably 0.001 to 1.0% by weight, more preferably 0.01 to 0.5% by weight based on the raw material. When the content of the surfactant exceeds 1.0% by weight, the effect is no longer improved, and troubles in the extruder and deterioration of the polymer may be caused.

Although it is possible to obtain a certain degree of whiteness and hiding degree of the film only by including such fine bubbles, it is difficult to obtain sufficient image clarity. Therefore, it is preferable to contain the above-mentioned particles, particularly a white pigment and a fluorescent whitening agent. In addition, if necessary as additives other than the above, as long as the performance as a photographic printing paper support of the required use is not impaired, an antistatic agent, a stabilizer, a lubricant, a crosslinking agent, an antiblocking agent,
It may contain an antioxidant, a colorant (dye or pigment), a light-blocking agent, an ultraviolet absorber, and the like.

In general, a white polyester film as a support for photographic printing paper is preferable because the whiteness and hiding degree are higher, and the surface roughness on the image forming layer side is smaller, so that the finished image is excellent in sharpness. These characteristics allow the white pigment, fluorescent whitening agent, fine bubbles, and the like to be designed in accordance with the level required for photographic paper. Further, as long as the properties finally obtained satisfy the requirements as a support for photographic printing paper, a multilayer structure may be employed. For example, it may be a co-extruded laminated film. Even with such a multilayer structure, whiteness, hiding degree, and surface roughness can be designed to any values.

The whiteness of the white polyester film used in the present invention is such that the b value, which is an index indicating yellowness, is 2.0 or less,
Preferably it is 1.0 or less, more preferably 0.5 or less. If the b value exceeds 2.0, yellowness becomes strong and whiteness becomes insufficient, which is not preferable. Further, the opacity (OD), which is an index indicating the concealability of the white polyester film used in the present invention, is 0.3 or more, preferably 0.4 or more. If the OD is less than 0.3, the prevention of light transmission becomes insufficient and the photographic image becomes unclear, which is not preferable.

When fine bubbles are contained in a white polyester film, the apparent density (ρ) is usually 0.6 to 1.2 g / cm ³ , preferably 0.7 to 1.1 g / cm ³ .
g / cm ³ . If ρ is less than 0.6 g / cm ³ , rupture frequently occurs during film formation, and productivity tends to be poor. When ρ exceeds 1.2 g / cm ³ , the cushioning property, which is a characteristic of the polyester containing fine cells, tends to be poor.

Next, the coating layer provided on the white polyester film in the present invention will be described. In the present invention, the coating layer after coating the coating solution on the film,
Although formed by drying, application may be performed after the production of the white polyester film, or may be performed in a white polyester film production process. The latter method is a so-called in-line coating method. In order to perform in-line coating, the coating liquid desirably satisfies several requirements, and the coating layer provided in the present invention is preferably provided by in-line coating. Such requirements include, for example, that there is no extreme cracking of the coating layer due to stretching after coating, that the coating properties are good, that the performance is sufficiently exhibited even in a thin film, that the coating liquid is aqueous, and the like. It is to satisfy.

The in-line coating referred to here is a method in which various raw materials such as polyester are melt-extruded, and then applied at an arbitrary place from the biaxial stretching to the heat setting and winding up. A substantially amorphous unstretched sheet formed by quenching, or a uniaxially stretched film after being stretched in the longitudinal direction (also called longitudinal direction) (before being stretched in the transverse direction), biaxial before heat fixing It is applied to any of the stretched films. Among them, a method in which the film is applied to a polyester film stretched uniaxially in the longitudinal direction and stretched in the horizontal direction in a dried or undried state is excellent. The reason is that film formation and coating and drying can be performed at the same time, so there is an advantage in manufacturing cost, it is possible to apply a thin film because it is stretched after coating, and high temperature where heat treatment performed after coating is not achieved by other methods Therefore, the coating film and the polyester film are strongly adhered to each other.

In order to perform in-line coating, the coating solution is preferably an aqueous solution from the viewpoint of safety and working environment. The coating solution used in the present invention is a coating solution containing an aqueous polyester and an aqueous epoxy group-containing compound. Liquid is required. However, in order to improve the stability, dispersibility, coatability and the like of the coating solution, a small amount of an organic solvent can be used in combination as needed. The same applies to the aqueous polyester and the aqueous epoxy group-containing compound described below. Further, depending on the organic solvent contained in these raw materials, it is possible that the organic solvent is eventually contained in the coating composition.

As the organic solvent, a relatively hydrophilic one is preferably used, and specific examples thereof include aliphatic and alicyclic alcohols, glycols, esters, ethers, and amide compounds. More specifically, alcohols such as methanol, ethanol, isopropanol and n-butanol; glycols such as ethylene glycol, propylene glycol and diethylene glycol; esters such as ethyl acetate and amyl acetate; ethers such as methyl cellosolve and ethyl cellosolve. , N-butyl cellosolve, t-butyl cellosolve, dioxane, tetrahydrofuran, and the like; ketones such as acetone and methyl ethyl ketone; and acetonitrile, N-methylpyrrolidone, N, N-dimethylformamide and the like. It is. These organic solvents may be used alone or in combination of two or more as needed.

When the main component of the coating liquid and each coating agent used is water, the compound may be forcibly dispersed with a surfactant or the like. This is preferable from the viewpoint of dispersion stability of the coating solution. The self-dispersion type coating agent is a coating agent in which various hydrophilic groups are introduced into a compound by a chemical bond. For example, as nonionic, a hydroxyl group, polyether, as anionic, sulfonic acid, carboxylic acid, phosphoric acid and salts thereof, and as cationic, a hydrophilic component such as an onium salt represented by a quaternary ammonium salt may be mentioned. However, these chemical species can be introduced by copolymerization or grafting to form a self-dispersing coating agent.

As a method of applying a coating solution to a polyester film, for example, Yuji Harazaki, Maki Shoten, 1979
A reverse roll coater, a gravure coater, a rod coater, an air doctor coater or a coating device other than these can be used as shown in "Coating System" published in 1998. The thickness of the finally formed coating layer is usually 0.001 to 10 μm, preferably 0.1 to 10 μm.
010 to 5 μm, more preferably 0.015 to 2 μm
It is. If the coating layer is thin, the adhesiveness to the photographic photosensitive layer expected from the coating layer may not be sufficiently exhibited. On the other hand,
If the coating layer is thick, the coating layer acts like an adhesive, and the films wound up on the rolls adhere to each other,
What is called blocking occurs. Unnecessarily increasing the thickness of the coating layer is not preferable in terms of manufacturing cost and productivity.

The aqueous polyurethane used in the present invention means a water-soluble or water-dispersible polyurethane resin coating agent using water as a main coating medium. In the present invention, it is preferable to use at least one selected from polyester-based polyurethane, polyether-based polyurethane, and polycarbonate-based polyurethane. The polyester-based polyurethane, the polyether-based polyurethane, and the polycarbonate-based polyurethane in the present invention are polyester polyols, polyether polyols, and polycarbonate polyols, respectively, which are one of the main constituent polyols of the polyurethane. is there. In addition, acrylic polyols and the like are often used.

As the components constituting such a polyurethane resin, the following polyols, polyisocyanates,
Examples thereof include a chain extender and a crosslinking agent. The above polyester polyols can be obtained, for example, by reacting a dicarboxylic acid and a glycol according to a conventional method. Examples of the dicarboxylic acid component include aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid and 2,6-naphthalenedicarboxylic acid, aliphatic dicarboxylic acids such as adipic acid, azelaic acid and sebacic acid, and oxybenzoic acid and the like. Examples thereof include carboxylic acids and their ester-forming derivatives. Examples of the glycol component include aliphatic glycols such as ethylene glycol, 1,4-butanediol, diethylene glycol, and triethylene glycol, and 1,4-cyclohexanediene. Alicyclic glycols such as methanol, aromatic diols such as p-xylene diol, polyethylene glycol,
Examples thereof include polyoxyalkylene glycols such as polypropylene glycol and polytetramethylene glycol. These polyesters have a linear structure, but can be made into a branched polyester using a trivalent or higher ester-forming component.

Examples of polyether polyols include polyalkylene glycols such as polyethylene glycol, polypropylene glycol, polytetramethylene glycol, and copolymers thereof. Polycarbonate polyols can be obtained, for example, by reacting a carbonate ester and a diol. Examples of carbonates include ethylene carbonate, dimethyl carbonate, diethyl carbonate, diphenyl carbonate, dicyclohexyl carbonate, and the like.Examples of diols include 1,6-hexanediol, 1,4-cyclohexanediol, 4-cyclohexanedimethanol, 3-methyl-1,5-pentanediol, polyethylene glycol, polypropylene glycol, polycaprolactone diol, trimethylhexanediol,
1,4-butanediol and the like can be mentioned. Further, a polyester polycarbonate obtained by reacting a polycarbonate diol with a dicarboxylic acid or a polyester may be used.

Examples of polyisocyanates include tolylene diisocyanate, phenylene diisocyanate,
4,4'-diphenylmethane diisocyanate, 1,5
-Naphthalene diisocyanate, aromatic diisocyanate such as xylylene diisocyanate, hexamethylene diisocyanate, lysine diisocyanate, 4,
Aliphatic diisocyanates such as 4'-dicyclohexylmethane diisocyanate and isophorone diisocyanate are exemplified.

The aromatic polyurethane in the present invention is:
The above-mentioned polyisocyanate component is a polyurethane in which the polyisocyanate component is aromatic. Similarly, the aliphatic polyurethane refers to a polyurethane in which the polyisocyanate component is aliphatic. When synthesizing a polyurethane, an aromatic polyisocyanate and an aliphatic polyurethane are often used in combination, but a polyurethane having two or more kinds of aromatic polyisocyanate and aliphatic polyisocyanate in one molecule can also be particularly preferably used. . Of course, two or more aromatic polyurethanes, aliphatic polyurethanes, and copolymers of the former two types may be selected and used in combination.

Examples of chain extenders or crosslinking agents include ethylene glycol, propylene glycol, butanediol, hexanediol, diethylene glycol, trimethylolpropane, glycerin, hydrazine, ethylenediamine, diethylenetriamine, 4,4'-diaminodiphenylmethane, 4'-diaminodicyclohexylmethane, water and the like.

The polyurethane thus produced may contain a urea bond by the reaction between isocyanate and water or an amine compound. That is, the polyurethane in the present invention also includes polyurethane urea. The aqueous epoxy group-containing compound in the present invention is a coating agent for a compound containing a water-soluble or water-dispersible epoxy group using water as a main coating medium, and the compound has at least one epoxy group in the molecule. Above, preferably two or more.

Examples of such epoxy group-containing compounds include glycidyl ethers such as glycols, polyethers and polyols, glycidyl esters of carboxylic acids, and glycidyl-substituted amines.
Preferred are glycidyl ethers. These glycidyl compounds can be easily obtained by reaction with epichlorohydrin, but the synthesis method is not limited thereto. As specific examples, sorbitol polyglycidyl ether, sorbitan polyglycidyl ether, polyglycerol polyglycidyl ether, pentaerythritol polyglycidyl ether, diglycerol polyglycidyl ether, triglycidyl tris (2
-Hydroxyethyl) isocyanurate, glycerol polyglycidyl ether, trimethylolpropane polyglycidyl ether, resorcinol diglycidyl ether, neopentyl glycol diglycidyl ether,
1,6-hexanediol diglycidyl ether, ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, polytetramethylene glycol diglycidyl ether, adipic acid diglycidyl ether,
Examples include, but are not limited to, orthophthalic acid diglycidyl ether, hydroquinone diglycidyl ether, bisphenol S diglycidyl ether, terephthalic acid glycidyl ester, dibromoneopentyl glycol diglycidyl ether, and the like. Epoxy emulsions are also sold by various companies. For example, "Denacol EM-125" manufactured by Nagase Kasei Kogyo Co., Ltd.
"Denacol EX-1101""Denacol EX-
1102 "and" Denacol EX-1103 ", but are not limited thereto.

In addition, two or more of these epoxy group-containing compounds may be used in the coating solution, and it is natural that some or more kinds of the compounds are usually mixed in the course of compound synthesis. In the present invention, it is an important requirement to provide a coating layer on a polyester film using a coating solution containing the aqueous polyurethane and the aqueous epoxy group-containing compound in a certain ratio. The dry weight ratio of the epoxy group-containing compound (aqueous polyurethane / aqueous epoxy group-containing compound) is 10/90 to 8
0/20, preferably 10/9
0-75 / 25, more preferably 15 / 85-70 /
30.

When the ratio of the aqueous polyurethane / aqueous epoxy group-containing compound is less than 10/90, the coating layer provided is not excellent in adhesion to a polyester film as a support, and the water resistance of the coating layer is poor. Further, the resulting film has poor blocking properties. On the other hand, when the ratio of the aqueous polyester / aqueous epoxy group-containing compound is larger than 80/20, the adhesiveness between the obtained coating layer and the overcoated photographic photosensitive layer is unfavorably deteriorated.

The present invention is characterized in that a coating solution containing a specific plurality of compounds in a specific ratio is used as described above. However, as long as the gist of the present invention is not impaired, other compounds may be used as aqueous polyurethane and aqueous polyurethane. An amount of 40% by weight or less on a dry weight basis with respect to the total amount of the epoxy group-containing compound may be blended. For example, inorganic or organic fine particles, wax, antistatic agent, surfactant, defoamer, coating improver, thickener, antioxidant, ultraviolet absorber, foaming for the purpose of improving blocking property and slipperiness Agents, dyes, pigments and the like.

The film before coating may be subjected to a chemical treatment or a discharge treatment in order to improve the coating properties and adhesion of the coating solution to the film. Further, for the purpose of improving the coatability, adhesiveness and the like between the polyester film of the present invention and the photographic photosensitive layer, a discharge treatment may be performed after the formation of the coating layer. Various photographic papers can be made by providing at least one photographic image forming layer on the photographic paper support of the present invention.
For example, a silver halide photographic emulsion layer can be provided.

Such a photographic emulsion preferably uses gelatin as a main binder. As the silver halide emulsion, various ordinary silver halide emulsions can be arbitrarily used. The emulsion can be chemically sensitized by a conventional method, and can be optically sensitized to a desired wavelength region by using a sensitizing dye. Further, an antifoggant, a stabilizer, a hardener and the like can be added to the silver halide emulsion. Examples of the hardening agent include aldehyde, aziridine, isoxazole, epoxy, vinyl sulfone, acryloyl, carbodiimide, triazine, polymer,
In addition, maleimide-based, acetylene-based, and methanesulfonic acid ester-based hardeners can be used alone or in combination of two or more. Also, plasticizers, dispersions (latex) of water-insoluble or hardly soluble synthetic polymers, couplers, coating aids, antistatic agents, formalin scavengers, optical brighteners, matting agents, lubricants, image stabilizers, surfactants And a color fog inhibitor, a development accelerator, a development retarder and a bleaching accelerator.

The photographic light-sensitive material can be provided with an auxiliary layer such as a protective layer, a filter layer, a back coating layer, an antihalation layer, an anti-irradiation layer, and an intermediate layer, in addition to the silver halide emulsion layer. Such a photographic photosensitive layer and other layers are appropriately selected depending on the intended use, and are not limited to the examples shown here.

[0055]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to the following examples unless it exceeds the gist of the present invention. The evaluation method in the examples is as follows. (1) Dry weight of coating liquid (coating agent) It was determined according to JIS K 5407-4. (2) Intrinsic viscosity of polyester ([η]) (dl /
g) 1 g of polyester is phenol / tetrachloroethane =
Dissolved in 100 ml of a 50/50 (weight ratio) mixed solvent,
It was measured at 30 ° C. (3) Opacity (OD) The transmitted light density under the G filter was measured using a Macbeth densitometer (TD-904). (4) b value Tokyo Denshoku Co., Ltd. color analyzer TC1800MK
Using type II, b according to the method of JISZ-8722
The value was measured. (5) Apparent density of film (ρ) (g / cm ³ ) A 10 cm × 10 cm square sample was cut out from an arbitrary portion of the film, and its weight was measured. Next, the thickness at nine arbitrary points was measured with a micrometer, and the weight per unit volume was calculated from the average value and the weight. The number of measurements was five, and the average was taken as the film density. (6) Image forming layer (gelatin layer) adhesion 1 [dry] A gelatin layer containing a hardener, a latex, a matting agent, and a yellow dye for making the evaluation result easy to understand becomes 5 μm in thickness after drying. And after hardening sufficiently,
The humidity was sufficiently adjusted at 23 ° C. and 50% RH. In this atmosphere, 100 square crosscuts were made at 1 mm intervals from the surface of the gelatin layer, and Nitto Denko's "Polyester Adhesive Tape No. 31" was adhered to the crosscut with care so as to prevent air bubbles from entering. A metal roll having a load of 2 kg was reciprocated 20 times on the tape. Thereafter, the peel test was performed by bending the base polyester film side to 180 °. One end of the polyester film was connected to a 1 kg weight, and a peeling test was performed so that peeling in a 180 ° direction started after the weight dropped naturally by a distance of 45 cm. The situation at this time was visually observed and evaluated according to the following criteria.

[0056]

[Table 1] ───────────────────────────── Evaluation status ─────────────── ◎ 良好 (Good): No peeling ○ (Normal): Peeled less than 30% △ (Somewhat bad): Peeled from 30% to less than 80% × (Poor): 80% Above peeling ───────────────────────────── The evaluation result is preferably 以上 or more, more preferably ◎. (7) Image Forming Layer (Gelatin Layer) Adhesion 2 [Wet] After a gelatin layer was provided and humidified in the same manner as in (6) above, a cross cut was similarly made. Using a felt that was immersed in water and sufficiently squeezed, it was reciprocated 30 times with a load of 500 g using Taihei Rika "rubbing tester". At this time, the remaining amount of the gelatin layer was visually observed and evaluated according to the following criteria.

[0057]

[Table 2] ───────────────────────────── Evaluation status ─────────────── ◎ (good): 100% remaining ○ (normal): 70% or more remaining Δ (slightly poor): 20% or more and less than 70% remaining × (bad): 20 % Remaining ───────────────────────────── The evaluation result is preferably ○ or more, and ◎ is more preferable. (8) Practical properties as photographic paper Only the films having good adhesion to the image forming layer in (6) and (7) were evaluated as follows. A gelatin layer containing a photoreceptor was coated on one side of the film to form a photosensitive layer, and exposed and developed to form an image. The quality of the obtained image was evaluated for the following items. Resolution Rank A: High resolution was obtained and high quality.

Rank B: The resolution is slightly inferior, but practically acceptable. Rank C: Practical problem due to poor resolution. Contrast Rank A: A high-quality image with clear contrast was obtained. Rank B: The contrast is slightly inferior, but practical.

Rank C: The contrast is low and the image quality is poor. Color tone Rank A: Good color tone was shown. Rank B: Inferior color tone due to influence of yellow color. Next, a method for producing a polyester film used in Examples will be described below. (Production of Polyester A) Dimethyl terephthalate 100
Starting parts by weight and 60 parts of ethylene glycol,
0.09 parts by weight of magnesium acetate tetrahydrate was placed in a reactor as a catalyst, the reaction starting temperature was set at 150 ° C., and the reaction temperature was gradually increased with the removal of methanol, and the temperature was increased to 230 ° C. after 3 hours. After 4 hours, the transesterification reaction was substantially completed. To this reaction mixture, 0.04 part of ethyl acid phosphate and 0.04 part of antimony trioxide were added, and a polycondensation reaction was performed for 4 hours and 30 minutes. That is, the temperature was gradually raised from 230 ° C. to 280 ° C. on the other hand,
The pressure gradually decreases from normal pressure, and finally 0.3mmHg
And After 4 hours and 30 minutes from the start of the reaction, the reaction was stopped, and the polymer was discharged under nitrogen pressure. The intrinsic viscosity of the obtained polyester was 0.65. Next, the obtained polymer was treated at 225 ° C. under 0.3 mmHg under the conditions of 1 mm.
The old layer polymerization was performed for 0 hours. The intrinsic viscosity of the obtained polyester was 0.81. (Production of Polyesters B to D) Polyester A was dried, and polyesters B to D were obtained using a vented twin-screw extruder according to the formulation shown in Table 1 below.

[0060]

[Table 3] (1-1. Production of White Polyester Film: Polyester Film 1) 35 parts by weight of polyester B, 10 parts by weight of polyester C, 5 parts by weight of polyester D, and 50 parts by weight of polyester A were uniformly blended, and
After drying at 80 ° C. for 4 hours, the sheet was extruded into a sheet shape from an extruder set at 285 ° C., and rapidly cooled and solidified by a rotating cooling drum set at a surface temperature of 30 ° C. using an electrostatic application cooling method. Thus, an amorphous sheet was obtained. The obtained amorphous sheet is stretched 3.0 times in the longitudinal direction at 83 ° C., then stretched 3.8 times in the transverse direction, and heat-treated at 245 ° C. for 6 seconds to have a thickness of 188 μm and an opacity (OD). 1.
6. A biaxially stretched white polyester film having a b value of -0.6 was obtained. (1-2. Production of White Polyester Film: Polyester Films 2 and 3) Biaxial stretching was performed in the same manner as polyester film 1 except that the amount of polyester was changed as shown in Table 2 in the production of polyester film 1. A white polyester film was obtained. Table 3 below shows the film properties of the polyester films 1 to 3.

[0061]

[Table 4]

[0062]

[Table 5] (2. Production of white polyester film containing fine bubbles:
Polyester film 2) 12.5 parts by weight of polyester B, 5 parts by weight of polyester D, polyester A 7
2.5 parts by weight were blended and dried at 180 ° C. for 4 hours. Thereafter, 10 parts by weight of a crystalline polypropylene homopolymer chip having a melt flow index of 5.5 and 0.2 part by weight of a silicone-based surfactant (trade name: BH193, manufactured by Toray Silicone Co., Ltd.) were blended and uniformly blended. Thereafter, the sheet is extruded into a sheet shape from an extruder set at 290 ° C., and rapidly cooled and solidified by a rotating cooling drum set at a surface temperature of 40 ° C. by using an electrostatic application cooling method, to a thickness of 247 μm.
m of substantially amorphous sheet was obtained. The obtained amorphous sheet is stretched 2.9 times in the longitudinal direction at 83 ° C., then stretched 3.2 times in the transverse direction, and heat-treated at 245 ° C. for 6 seconds to have a thickness of 38 μm and a degree of concealment (OD). A white polyester film 7 containing biaxially stretched microbubbles having a 0.5, b value of -4.5, and an apparent density (ρ) of 1.0 g / cm ³ was obtained.

Hereinafter, a coating method for providing a coating layer on a polyester film will be described. (Coating method) During the above-mentioned white polyester film manufacturing process, the concentration of the coating solution is adjusted by using a bar coater on the film after longitudinal stretching and before horizontal stretching so that the coating solution having the composition described below has a thickness suitable for each example. Coating was performed by adjusting the coating thickness. The coating thickness in the table is that after drying and transverse stretching, that is, the thickness of the coating layer on the film after biaxial stretching heat treatment.

Next, the contents of the coating agent used in the examples will be described. (Aqueous polyurethane) Aqueous polyurethanes A1 to A6 were used. The resin is synthesized by a conventional method, neutralizing if necessary,
Dispersed in water. The composition is as follows. In addition, all of the following parts represent parts by weight.

A1: Polyester polyol (a polyester polyol comprising 664 parts of terephthalic acid, 631 parts of isophthalic acid, 472 parts of 1,4-butanediol, and 447 parts of neopentyl glycol, and adipic acid 32
1880 parts of dimethylolpropionic acid, and 1880 parts of a polyester polyol having a pendant carboxyl group) and 160 parts of tolylene diisocyanate A2: The same polyester polyol 1880 as A1 above
Aliphatic polyester polyurethane A3 consisting of 160 parts of 4,4'-dicyclohexylmethane diisocyanate in part A3: polytetramethylene glycol (molecular weight: 200
0) 31.5 parts, neopentyl glycol 17.2 parts,
Aromatic polyether polyurethane consisting of 7.8 parts of dimethylolpropionic acid, 1.5 parts of trimethylolpropane and 42.0 parts of tolylene diisocyanate A4: 31.5 parts of polyethylene glycol, 17.2 parts of neopentyl glycol, dimethylol 7.8 parts of propionic acid, 1.5 parts of trimethylolpropane, 4,4 '
Aliphatic polyether polyurethane A5 consisting of 42.0 parts of dicyclohexylmethane diisocyanate A5: polycarbonate polyol (472 parts of diethyl carbonate, 416 parts of 1,5-pentanediol,
Aromatic polycarbonate polyurethane comprising 500 parts of 1,6-hexanediol (472 parts), tolylene diisocyanate 160 parts and dimethylolpropionic acid 58.5 parts A6: 4,4'-dicyclohexyl is used instead of tolylene diisocyanate in aqueous polyurethane A5. Aliphatic polycarbonate polyurethane (aqueous epoxy group-containing compound) using methane diisocyanate Aqueous epoxy group-containing compounds B1 and B2 were used.

The contents (main components) are as follows. B1: tetraglycerol tetraglycidyl ether B2: sorbitol triglycidyl ether (aqueous acryl) polyacrylic resin compound aqueous dispersion C
1 was used.

C1: 45 mol% of methyl methacrylate,
Copolymer (melamine compound) composed of 30 mol% of n-butyl acrylate, 20 mol% of styrene, and 5 mol% of acrylic acid A melamine compound D1 was used. D1: Water-soluble melamine compounds centering on mononuclear, dinuclear, and trinuclear compounds of methylol or methoxymethyrol melamine having almost four functions Examples 1 to 11 and Comparative Examples 1 to 15 The polyester film described in Table 4 was provided with the coating layer also described in Table 4.
However, in Table 4, numerical values indicating the ratio of the aqueous polyester and the aqueous epoxy group-containing compound in the coating layer mean the weight ratio (% by weight) based on the dry weight of each coating agent. The thickness of the coating layer is the thickness on the finally completed film.

Comparative Examples 16 and 17 As shown in Table 4, each white polyester film was not provided with a coating layer.

[0069]

[Table 6]

[0070]

[Table 7] Next, the evaluation results of each example are shown in Table 5 below. In the evaluation of the photographic paper practical characteristics in the table,-means that the evaluation was not performed because the adhesiveness to the photographic image forming layer was insufficient.

[0071]

[Table 8]

[0072]

[Table 9]

[0073]

According to the present invention described above, a polyester-based photographic printing paper support provided with a coating layer having good adhesion to a photographic image forming layer can be easily provided. The industrial value of is very large.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI G03C 1/795 G03C 1/795 // C09D 163/00 C09D 163/00 175/04 175/04 B29K 67:00 B29L 7:00 9:00

Claims (6)

[Claims] 1. An aqueous polyurethane and an aqueous epoxy group-containing compound in a dry weight ratio of 10/90 to 80/2.
The coating solution containing the coating solution at a ratio of 0 has an opacity (OD) of 0.3.
A method for producing a support for polyester-based photographic printing paper, wherein the support is applied to at least one side of a white polyester film having a b value of less than 2.0 and dried. 2. The polyester-based photographic support according to claim 1, wherein the total dry weight of the aqueous polyurethane and the aqueous epoxy group-containing compound is 60% or more based on the dry weight of the coating solution. Method. 3. The process for producing a polyester-based photographic support according to claim 1, wherein the aqueous polyurethane is at least one selected from polyester-based polyurethane, polyether-based polyurethane and polycarbonate-based polyurethane. 4. The method for producing a support for a polyester-based photographic printing paper according to claim 1, wherein the white polyester film contains a white pigment. 5. The white polyester film according to claim 1, wherein the white polyester film contains a large number of fine closed cells having an apparent density (ρ) of 0.6 to 1.2 g / cm ^3. A method for producing a support for polyester-based photographic printing paper. 6. The method for producing a support for a polyester-based photographic printing paper according to claim 1, wherein the coating is performed in a process for producing the polyester film.