JPH0434139B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a photographic resin-coated paper in which at least one side of a paper or synthetic paper base is coated with a resin composition comprising at least a titanium dioxide pigment and a resin, and more particularly to a resin-coated paper for use in photography. Micro grit on the coated resin surface
This invention relates to photographic resin-coated paper with good surface quality in which almost no appearance of . The term "microgrit" as used herein refers to minute foreign matter or minute grains that appear on the surface of the coated resin in photographic resin-coated paper in which at least one side of the paper or synthetic paper substrate is coated with a resin composition. There are various causes of microgrit, but for example, the formation of microgrit that appears on photographic resin-coated paper manufactured by melt-extruding photographic thermoplastic resin onto at least one side of a paper or synthetic paper substrate using a melt extruder. This is because (1) the thermoplastic resin itself tends to generate a lot of gel, and (2) the temperature cannot be maintained at the appropriate temperature when the molten resin is extruded from the melt extruder through the die into a film. , if the flow is uneven, (3) if the screen attached to the breaker plate in the melt extruder is dirty, (4) if there are cracks in the barrel liner in the melt extruder, (5) if the melt Examples include cases where the extruder is insufficiently kneaded, but these can often be resolved relatively easily by skilled engineers. However, the most difficult countermeasure against microgrit is when microgrit occurs in photographic resin-coated paper in which the paper or synthetic paper substrate is coated with a resin composition consisting of at least a thermoplastic resin and a pigment. In the first place, the method of incorporating pigments into a thermoplastic resin, preferably a polyolefin resin, is to prepare a so-called master batch in which pigments are contained in a resin at a high concentration in advance, and then dilute and mix them with a diluent resin to a desired ratio. However, it is usual to prepare and use a so-called compound in which a desired composition ratio of pigment is contained in a resin from the beginning. However, when preparing a masterbatch or compound by melt-kneading a thermoplastic resin and a pigment using an ordinary melt-kneading machine such as a Banbury mixer or a kneader, relatively coarse pigment particles are mixed in the thermoplastic resin. Alternatively, aggregates of titanium dioxide pigment tend to be dispersed as they are without being dispersed in a fine state, resulting in the presence of coarse pigment particles in the masterbatch or compound. As a result, microgrit is deposited on the resin side of a photographic resin-coated paper in which at least one side of the paper or synthetic paper substrate is coated with a resin composition comprising a pigment and a resin produced using the masterbatch or the compound. will occur. The occurrence of microgrit in resin-coated papers used as photographic supports causes serious photographic defects. That is, when a person is photographed on a photographic paper having a resin-coated paper containing microgrit as a photographic support, if microgrit appears in areas such as the face, the photograph has no commercial value. By the way, titanium dioxide pigments are usually used as pigments contained in the resin layer on the emulsion-coated side of resin-coated paper used as a photographic support because they have excellent whiteness, hiding power, resolution, etc. is well known. Resin-coated papers for photographs are also already known, for example as disclosed in US Pat. It is well known that the resin layer contains a titanium dioxide pigment, a colored pigment, a fluorescent whitening agent, and the like. Another type of photographic resin-coated paper is a resin composition containing a white pigment such as titanium dioxide, the paper base of which is polymerized and cured by electron beam irradiation, as disclosed in JP-A-57-30830. Photographic resin-coated papers coated with are also known. However, for photographic resin-coated paper in which at least one side of the paper or synthetic paper substrate is coated with a resin composition comprising at least a titanium dioxide pigment and a resin, a masterbatch or compound of the titanium dioxide pigment as described above may be used. When manufactured by using the resin-coated photographic paper, as mentioned above, there is a tendency for a large number of microgrits caused by coarse particles of the pigment, that is, titanium dioxide pigment in this case, to occur frequently on the resin surface of the photographic resin-coated paper. There was a serious problem. Therefore, an object of the present invention is to provide a method in which the generation of microgrit is prevented or significantly suppressed.
It is an object of the present invention to provide a photographic resin-coated paper containing a titanium dioxide pigment in a resin layer and having a good surface quality. That is, in a photographic resin-coated paper in which at least one surface of a paper or synthetic paper substrate is coated with a resin composition consisting of at least a titanium dioxide pigment and a resin, the titanium dioxide pigment is present in one molecule. 2 of formula A and formula B described in claim 1
The object of the present invention is to provide a photographic resin-coated paper whose surface is treated with a polyether-modified siloxane containing at least one substituent group. As a titanium dioxide surface treatment agent that significantly suppresses the generation of microgrit in the photographic resin-coated paper of the present invention, only a specific polyether-modified siloxane (hereinafter sometimes abbreviated as siloxane in the present invention) is used. be effective,
As an example, organosilicones such as those disclosed in Japanese Patent Publication No. 3430/1983, such as siloxanes such as alkyl polysiloxanes, alkylaryl polysiloxanes, and alkylhydrodiene polysiloxanes, generate enough microgrit for use in photographic resin-coated paper. cannot be suppressed. As the siloxane of the present invention, any polyether-modified siloxane can be used as long as it contains at least one of each of the two substituents of formula A and formula B described in the specification of the present application, but specific compounds are listed below. Then, it will be as follows. Titanium dioxide pigments are usually made from coarse pigment → wet grinding → classification → surface treatment (using an inorganic surface treatment agent) →
It is manufactured through filtration, washing, dehydration → drying → (coarse pulverization) → fine pulverization. The method of surface treatment of titanium dioxide with siloxane in the present invention may be carried out after the drying step in the above steps, that is, at any point between the drying step and after the pulverization, but it may be carried out before or during the pulverization. is preferable, and may also be carried out after pulverization. If surface treatment is performed after pulverization, further pulverization may be performed if necessary. The siloxane used in the present invention may be used to surface-treat titanium dioxide as it is, or may be appropriately diluted with an organic solvent such as ethanol or acetone. As a surface treatment method, for example, when processing with a steam mill, titanium dioxide and a predetermined amount of the siloxane of the present invention may be supplied to the steam mill so as to achieve the desired treatment amount, and the surface treatment may be performed while pulverizing. In addition, as a surface treatment method, for example, when processing with a Henschel mixer, titanium dioxide can be ground with a grinder such as a steam mill, and then mixed with the siloxane of the present invention in the Henschel mixer to perform the surface treatment. good. Further, if necessary, further pulverization may be performed using a pulverizer such as an air mill. If necessary, coarse pulverization using a hammer mill or the like may be performed before fine pulverization. In the present invention, the surface treatment amount of siloxane to titanium dioxide is 0.05 to 0.05 to titanium dioxide.
If it is 1.0% by weight and less than 0.05% by weight, the effect of the present invention cannot be obtained, and if it exceeds 1.0% by weight, resulting in an excessive surface treatment amount, for example, when kneading with the resin using a Banbury mixer, etc. It tends to cause slippage and does not provide sufficient dispersion. Normally, when preparing a masterbatch by kneading titanium dioxide pigment into a thermoplastic resin such as polyethylene resin using a Banbury mixer, etc., the higher the titanium dioxide content, the more difficult it is to knead; A lubricant is often used when sufficient dispersibility is not obtained to suppress this. For example, in the dispersion test disclosed in Japanese Patent Publication No. 60-3430,
Although only about 1% of the titanium dioxide pigment is added to the resin in order to obtain sufficient dispersibility, zinc stearate as a lubricant is added to the titanium dioxide pigment in an amount of 10%. Generally, masterbatches used in the photographic industry contain 30 to 50% by weight of titanium dioxide pigment in the resin for ease of handling, cost, etc. Even with surface treatment, a considerable amount of lubricant is required to obtain good dispersibility. Even so, when the above-mentioned masterbatch is applied to photographic resin-coated paper used as a photographic support, it is only possible to obtain a level that does not sufficiently suppress the generation of microgrit. In addition, commonly used lubricants such as zinc stearate and other fatty acid metals are exposed to high temperatures of 300°C or higher when melt-extruded and coated on the surface of a substrate such as paper through the die of a melt-extruder. Thermal decomposition occurs, and the decomposed gas components condense when they come into contact with the hood or exhaust hole on the die, and sometimes fall onto the resin-coated surface that is melt-extruded onto the surface of a substrate such as paper, resulting in relatively large particles. Spot-like foreign matter will be generated (this is sometimes called resin sagging).
If such foreign matter occurs, the paper can no longer be used as a resin-coated photographic paper. Therefore, in order to sufficiently suppress the generation of microgrit, it is necessary to use a relatively large amount of lubricant (for example, zinc stearate) when preparing the masterbatch.On the other hand, if a relatively large amount of lubricant is used, the resin The problem of sagging occurs, and the reality is that manufacturers of resin-coated paper for photographs are constantly troubled by this contradiction. In order to solve this problem, the present inventors conducted intensive research and as a result, it became possible to overcome the above-mentioned contradiction by applying the siloxane of the present invention to titanium dioxide surface treatment. That is, the siloxane in the present invention is
It has been found that a surface-treated titanium dioxide pigment of 0.05 to 1.0% by weight makes it possible to obtain photographic resin-coated paper with little microgrit generation and almost no resin sag, without the use of any particular lubricant. Furthermore, in order to prepare a masterbatch without the formation of microgrits, it is advantageous to include small amounts of fatty acid metal salts. In this case, in order to suppress the occurrence of resin sag as much as possible, it is sufficient to add about 0.1 to 5.0% by weight of a fatty acid metal salt such as zinc stearate to the titanium dioxide pigment when kneading with a Banbury mixer or the like. . The titanium dioxide pigment used in the practice of the present invention can be one made by a chlorine method or a sulfuric acid method, and can be a rutin type or anatase type, but the whiteness It is advantageous to use the anatase form. Furthermore, even if the titanium dioxide is so-called untreated titanium dioxide, which is not subjected to any surface treatment, various inorganic surface treatment agents such as hydrated aluminum oxide, hydrated aluminum oxide, etc. It may be so-called inorganic surface-treated titanium dioxide which has been surface-treated with silicon oxide, hydrated titanium oxide, hydrated zirconium oxide, zinc hydroxide, magnesium hydroxide, a manganese compound, a phosphoric acid compound, or a combination of several of these. The amount of these inorganic surface treatment agents to be treated is preferably 0.2 to 1.2% by weight, and 0.2 to 0.6% by weight based on titanium dioxide.
% by weight (calculated in the form of Al ₂ O ₃ ) is particularly preferred. According to the results of studies conducted by the present inventors, hydrous aluminum oxide is preferable as the inorganic surface treatment agent;
In addition, the amount of treatment is compared to titanium dioxide.
Preference is given to between 0.2 and 1.2% by weight, particularly preferred between 0.2 and 0.6% by weight (calculated in the form of Al ₂ O ₃ ). In this way, the surface is treated using hydrated aluminum oxide as an inorganic surface treatment agent at 0.2 to 1.2% by weight, particularly preferably 0.2 to 0.6% by weight (calculated in the form of Al ₂ O ₃ ) based on titanium dioxide. It has been found that not only the generation of microgrit is extremely small, but also the generation of die lip stains is significantly suppressed, and troubles during processing operations are significantly reduced. Die lip stain refers to needle-shaped or icicle-shaped deposits or stains that occur at the tip of the die lip when a thermoplastic resin composition containing titanium dioxide pigment is melt-extruded into a film from the slit die of a melt extruder. When this happens, unfortunately, it tends to grow larger and larger as the melt extrusion time elapses. If this die lip stain occurs during melt extrusion coating, streaks may appear in the vertical direction on the surface of the photographic resin-coated paper manufactured as is, or streak-like unevenness may occur due to uneven coating amount. In some cases, dirt adheres to the film and is coated, causing foreign matter to appear. As a result, the surface quality of resin-coated paper manufactured as a photographic support, for example, is significantly impaired, making it completely unsuitable as a photographic support that requires excellent surface quality and having no commercial value. In addition, the only way to completely remove die lip dirt once it has occurred is to stop production and clean the die lip, which requires a great deal of effort and time and causes a significant drop in productivity. It turns out. Resins used in the practice of the present invention include homopolymers or copolymers such as polyolefins, polystyrene, polyvinyl chloride, polyacrylic esters, linear polyesters such as polyethylene terephthalate, polycarbonates, polyamides such as nylon, cellulose esters, polyacrylonitrile, etc. For example, any resin that can be used to coat a resin film on a base paper such as ethylene-vinyl acetate copolymer and mixtures thereof may be used, but in particular thermoplastic resins such as polyolefin, polystyrene, polyethylene terephthalate, and polyvinyl chloride may be used. are preferred, and among them, polyolefin resins are particularly advantageous in terms of extrusion coating properties, good adhesion to the base paper, and cost. The polyolefin resin in the present invention refers to a homopolymer such as low density polyethylene, medium density polyethylene, high density polyethylene, polypropylene, polybutene, polypentene, or ethylene-
Copolymers consisting of two or more olefins such as propylene copolymers, linear low-density polyethylenes such as copolymers of ethylene and α-olefins, and mixtures thereof. Index (hereinafter simply referred to as MI) can be used alone or in combination. If the content of titanium dioxide pigment contained in the resin layer of the photographic resin-coated paper in the present invention is 5% by weight or less based on the resin, the hiding power will be insufficient as a photographic support; If it exceeds 40% by weight, the fluidity etc. decreases, which is undesirable.
Particularly preferred is a range of 7.5% to 25% by weight. It is preferable that a fatty acid metal salt is contained in the resin layer of the photographic resin-coated paper in the present invention.
Examples of these fatty acid metal salts include zinc stearate, calcium stearate, aluminum stearate, magnesium stearate, zirconium octylate, sodium palmitate, calcium palmitate, and sodium laurate. Further, the amount added is preferably low in order to reduce resin sag as much as possible, and is preferably in the range of 0.1% to 5% by weight based on titanium dioxide. Furthermore, in the resin layer of the photographic resin-coated paper according to the present invention, in addition to the titanium dioxide pigment and, if necessary, the fatty acid metal salt, white pigments such as zinc oxide, talc, and calcium carbonate, stearic acid amide, and arachidin. Fatty acid amides such as acid amides, tetrakis [methylene-3(3,5-di-tert-butyl-4-hydroxy-phenyl)propionate]methane, 2,6-di-tert-butyl-4-methyl-phenol, etc. Antioxidants, coloring pigments such as cobalt blue, navy blue, ultramarine, and cobalt violet, fluorescent whitening agents, and the like may be added. The photographic resin-coated paper in the present invention is a paper or a synthetic paper base (hereinafter simply referred to as base paper) that normally runs.
It is manufactured by melt-extruding a resin composition containing a heated and melted titanium dioxide pigment onto a film through a slit die. When the resin is a polyolefin resin, the melt extrusion temperature is preferably 200°C to 350°C. Further, before coating the resin composition on the base paper, it is preferable to subject the base paper to an activation treatment such as a corona discharge treatment or a fire treatment. There is no particular limit to the thickness of the resin layer of resin-coated paper, but it is generally 5.
Extrusion coatings to a thickness of the order of microns to 50 microns are advantageous. In addition, in ordinary resin-coated paper in which both sides of the base paper are coated with resin,
The resin surface containing titanium dioxide pigment has a glossy surface, a matte surface, a silky surface, etc. depending on its use.
The opposite back surface is usually a matte surface, and if necessary, the front surface or both the front and back surfaces can be subjected to activation treatment such as corona discharge treatment or flame treatment. The base paper used in the practice of the present invention may be ordinary natural pulp paper, synthetic fiber, or so-called synthetic paper made from synthetic resin film.
Natural pulp paper based on wood pulp of softwood pulp, hardwood pulp, softwood hardwood mixed pulp is advantageously used. There is no particular restriction on the thickness of the base paper, but a base paper with good surface smoothness is preferred, and its basis weight is preferably 50 g/m ² to 250 g/m ² . The base paper mainly composed of natural pulp, which is advantageously used in carrying out the present invention, can contain various polymeric compounds and additives. For example, as a dry paper strength enhancer, cationized starch, cationized polyacrylylamide, anionized polyacrylamide, carboxy-modified polyvinyl alcohol,
Sizing agents such as gelatin, fatty acid salts, rosin derivatives, dialkyl ketene dimer emulsions, petroleum resin emulsions, ammonium salts of styrene-maleic anhydride copolymer alkyl esters, etc. Pigments such as clay, kaolin, calcium carbonate, barium sulfate , titanium oxide, etc., as a wet paper strength agent, melamine resin, urea resin, epoxidized polyamide resin, as a fixing agent, polyvalent metal salts such as aluminum sulfate, aluminum chloride, cationically modified polymers such as cationized starch, etc.
As a PH regulator, caustic soda, soda carbonate, hydrochloric acid, etc., as an inorganic electrolyte, common salt, mirabilite, etc. In addition, dyes, fluorescent brighteners, latex, etc. can be contained in appropriate combinations. The photographic resin-coated paper of the present invention can be provided with various silver halide photographic emulsion layers.
For example, silver chloride, silver bromide, silver chlorobromide, silver iodobromide,
A silver chloroiodobromide emulsion layer can be provided. Also,
A multilayer silver halide photographic constituent layer can be provided by containing a color coupler in the silver halide photographic emulsion layer. As the binder for these silver halide emulsion layers, in addition to ordinary gelatin, hydrophilic polymeric substances such as polyvinylpyrrolidone, polyvinyl alcohol, and polysaccharide sulfate ester compounds can be used. Further, the above-mentioned silver halide emulsion layer can contain various additives. For example, sensitizing dyes include cyanine dyes and merocyanine dyes; chemical sensitizers include water-soluble gold compounds and sulfur compounds; antifoggants and stabilizers include hydroxy-triazolopyrimidine compounds and mercapto-heterocyclic compounds. Hardeners such as formalin, vinyl sulfone compounds, aziridine compounds, coating aids such as benzene sulfonate, sulfosuccinate salts, anti-staining agents, dialkylhydroquinone compounds, etc., development accelerators, etc.
Hydroquinone, phenidone, etc., ultraviolet absorbers, benzotriazole compounds, etc., as well as fluorescent whitening agents, sharpness-enhancing dyes, antistatic agents, PH
In addition to the regulator, a water-soluble iridium compound, a water-soluble rhodium compound, etc. can be contained in appropriate combinations during the production and dispersion of silver halide. Further, on the back side of the photographic resin-coated paper in the present invention, that is, on the support surface opposite to the side on which the photographic constituent layer, often the silver halide photographic constituent layer, is coated, anti-curl, antistatic, A coating layer consisting of a hydrophilic colloid layer called a back coat layer can be provided for the purpose of preventing adhesion and slipping. Such a back coat layer may contain a binder, a protective colloid, a curing agent, an antistatic agent, a surfactant, a matting agent, a latex, and the like. Next, in order to explain the present invention more specifically,
An example will be described. Example 1 Crude pigment → Wet grinding → Classification → Filtration, washing, dehydration →
After drying and pulverization, when producing anatase type titanium dioxide pigment by the sulfuric acid method, untreated titanium dioxide and a predetermined amount of siloxane [exemplified compound (5)] according to the present invention listed in Table 1 are placed in a steam mill. Surface treatment was performed while supplying and pulverizing. Thereafter, it was finely pulverized by passing it through an air mill. Regarding the seven types of titanium dioxide pigments obtained in this way, low-density polyethylene (density 0.92,
70 parts by weight of MI=7) and 30 parts by weight of titanium dioxide pigment were thoroughly kneaded at 150°C using a Banbury mixer to obtain masterbatches containing the above seven types of titanium dioxide pigments. On the other hand, a mixed stock of 50 parts by weight of bleached hardwood crust valve and 50 parts by weight of bleached softwood sulfite pulp was mixed with Canadian Standard Freeness 310.
ml, and further added to 100 parts by weight of pulp, 3 parts by weight of cationized starch, 0.2 parts by weight of anionized polyacrylamide, 0.4 parts by weight of alkyl ketene dimer emulsion (as ketene dimer content), and 0.4 parts by weight of polyaminopolyamide epichlorohydrin resin. A paper with a basis weight of 160 g/m ² was made.
The obtained wet paper paper was dried at 110°C and then impregnated with an impregnating solution consisting of 3 parts by weight of carboxy-modified polyvinyl alcohol, 0.05 parts by weight of a fluorescent brightener, 0.002 parts by weight of blue dye, 0.2 parts by weight of citric acid and 97 parts by weight of water. 25
After impregnating the paper with g/m ² , drying with hot air at 110°C, and calendering at a linear pressure of 90 kg/cm, both sides of the paper were subjected to corona discharge treatment to produce a base paper for photographic resin-coated paper. Next, apply high-density polyethylene (density
A 1:1 mixture of 0.96 g/cm ³ , MI=7) and low density polyethylene (density 0.92 g/cm ³ , MI=3) was coated at a resin temperature of 320°C using a melt extrusion coating machine to a thickness of 30μ. Coated. Next, 30 parts by weight of the masterbatch of the titanium dioxide pigment described above was applied to the surface of the base paper.
High-density polyethylene (density 0.96g/cm ³ , MI=7)
20 parts by weight and low density polyethylene (density 0.92g/
cm ³ , MI = 5) was coated to a thickness of 30μ at a resin temperature of 320°C.
Polyethylene resin coated papers containing titanium dioxide pigments were each produced. At that time, the surface of the polyethylene containing the titanium dioxide pigment was processed into a completely flat glossy surface, and the surface quality of the back polyethylene was processed into a paper-like matte surface. Table 1 shows the number of microgrits when resin compositions containing these titanium dioxide pigments were used. The number of microgrits was determined by the following method. <Number of Microgrits> The number of microgrits generated on the resin surface containing the titanium dioxide pigment of the photographic resin-coated paper produced by the method described in the Examples was visually counted.

[Table] From the results in Table 1, the siloxane [exemplary compound (5)] of the present invention was compared to untreated titanium dioxide.
It can be seen that all of the paper treated with a surface treatment of 0.05 to 1.0% by weight produced less microgrit and produced good photographic resin-coated papers. On the other hand, titanium dioxide surface-treated with 0.02 and 2.0% by weight both generate a lot of micro grit.
The resulting paper was unsuitable for use as a photographic resin-coated paper. Example 2 Coarse pigment → Wet grinding → Classification → Inorganic surface treatment (excluding untreated titanium dioxide) → Filtration, washing, dehydration → Drying → Coarse grinding (hammer mill) → Fine grinding to produce anatase-type titanium dioxide using the sulfuric acid method When producing pigments, prior to surface treatment with siloxane [exemplified compound (1)] in the present invention, in the inorganic surface treatment step of the above steps, sodium aluminate is added to the treatment amount as shown in Table 2. Inorganic surface treatment was performed using the solution. Thereafter, in the same manner as in Example 1, the siloxane surface treatment of the present invention was carried out at the treatment amounts shown in Table 2 (0.5% by weight based on titanium dioxide in each case). Thereafter, it was pulverized by passing it through an air mill. For comparison, comparisons were made using exactly the same procedure as the surface treatment with siloxane in the present invention, except that the siloxane in the present invention was replaced with dimethyl polysiloxane and methylhydrodiene polysiloxane. We created siloxane surface-treated titanium dioxide. Using the 6 types of siloxane surface-treated titanium dioxide of the present invention and the 6 types of siloxane surface-treated titanium dioxide for comparison thus obtained, photographic resin-coated paper was prepared in the same manner as in Example 1. Microgrit was measured in the same manner as above. The results obtained are shown in Table 2. Furthermore, die lip stain was measured by the method described below using the resin formulation described in Example 1 containing six types of siloxane surface-treated titanium dioxide according to the present invention. The results obtained are shown in Table 2. <Number of dye lip stains> A masterbatch containing the six types of titanium dioxide pigments listed in Table 2 was determined using the resin formulation described in Example 1 under the following conditions. Using a screw extruder with an extrusion port diameter of 65 mm and a melt extruder with a T-die of 750 mm width, the melt temperature
The number of stains generated on the die lip after melt extrusion for 2 hours at 320°C and screw rotation of 100 rpm is shown.

【table】

[Table] From the results in Table 2, it can be seen that the products subjected to the siloxane surface treatment of the present invention after being subjected to the hydrous aluminum oxide surface treatment prior to the siloxane surface treatment are good with less micro grit generation. On the other hand, microgrids were treated with dimethylpolysiloxane (No. 17 to 19) and methylhydrodiene polysiloxane (No. 20 to 22), which are outside the scope of the present invention, after being similarly subjected to hydrous aluminum oxide surface treatment. It can be seen that this occurs frequently, making it unsuitable for use as resin-coated paper for photography. In addition, in Nos. 14 to 16 in the present invention, that is, those in which the surface treatment amount of hydrous aluminum oxide is relatively large, the number of die lip stains increases as the amount of treatment increases, especially in the case of 2.0% by weight (No. 16). It can be seen that this occurs significantly. In addition, the resin surface containing titanium dioxide pigment of No. 11 to 16 photographic resin-coated papers was irradiated for 120 hours using a Suga Test Instruments Fedometer (FAL-25X-HCL model), and then the irradiated surface of each sample was When observed, sample No. 11 showed a slight tendency to yellow compared to samples No. 12 to 16. Therefore, prior to the siloxane surface treatment in the present invention, 0.2 to 1.2% by weight, particularly 0.2 to 0.6% by weight, of hydrated aluminum oxide is applied to titanium dioxide as a photographic resin-coated paper. It can be seen that the one with 0.5% by weight of surface treatment is the most preferable. Example 3 When producing anadase-type titanium dioxide by the sulfuric acid method through the same titanium dioxide production process as in Example 2, the inorganic surface was In the treatment step, an inorganic surface treatment was carried out using a sodium aluminate solution at a content of 0.6% by weight (calculated in the form of Al ₂ O ₃ ) based on titanium dioxide. Thereafter, titanium dioxide was obtained through the steps of filtering, washing, dehydration, drying, coarse pulverization (hammer mill), and fine pulverization (steam mill). Next, surface treatment was carried out by mixing with titanium dioxide in a Henschel mixer so that the amount of siloxane surface treatment according to the present invention as shown in Table 3 was obtained. Thereafter, it was finely pulverized by passing it through an air mill. For comparison, siloxane surface treatment with dioxide was performed using the same procedure as the surface treatment with siloxane in the present invention, except that the siloxane in the present invention was replaced with dimethylpolysiloxane. Created titanium. A masterbatch was prepared using the four types of siloxane surface-treated titanium dioxide of the present invention and three types of siloxane surface-treated titanium dioxide for comparison obtained in the same manner as in Example 1. however,
At this time, each zinc stearate was added as a lubricant in the amounts listed in Table 3. Thereafter, a photographic resin-coated paper was prepared in the same manner as in Example 1, and the microgrit was measured. In addition, during the production of photographic resin-coated paper, the degree of resin sag that adhered to or fell from the hood on the die of the melt extruder after a certain period of time was also determined. The results obtained are shown in Table 3.

[Table] (2) Dimethylpolysiloxane From the results in Table 3, in the case of the photographic resin-coated paper using siloxane surface-treated titanium dioxide in the present invention, microgrit slightly increases as the amount of lubricant (zinc stearate) decreases. Although there is a tendency for micro grit to occur, the number of micro grits generated is small in all cases, indicating that good photographic resin-coated paper can be obtained. However, even when the siloxane of the present invention is used, when the lubricant is added in an amount of 10% by weight based on the titanium dioxide pigment (No. 31), resin sag occurs significantly, and the operating conditions may deteriorate significantly. I understand. On the other hand, in the case of photographic resin-coated paper using dimethylpolysiloxane surface treatment, which is outside the scope of the present invention,
Even though the lubricant was added in an amount of 10% by weight based on the titanium dioxide pigment, a large number of micro-blits were generated, and the resulting paper was unsuitable for use as a photographic resin-coated paper. Furthermore, the occurrence of resin sagging was significant, and the operating conditions were seriously deteriorated.

Claims (1)

[Claims] 1. At least one surface of the paper or synthetic paper substrate is
In a photographic resin-coated paper coated with a resin composition consisting of at least a titanium dioxide pigment and a resin, the titanium dioxide pigment contains at least one substituent each of the following two types of formula A and formula B in one molecule. 1. A photographic resin-coated paper characterized by being surface-treated with a polyether-modified siloxane. Formula A; (In the formula, x is an integer from 0 to 4, a is a number from 1 to 50 on average, b is a number from 0 to 50 on average, R' is a hydrogen atom,
Represents an alkyl group or an acyl group. ) Formula B; [Formula] or [Formula] (In the formula, y is an integer of 0 to 4, R'' and R are saturated or unsaturated hydrocarbons having 1 to 30 carbon atoms that do not contain terminal unsaturated bonds, z represents an integer from 2 to 30.) 2 The amount of surface treatment of the polyether-modified siloxane relative to the titanium dioxide pigment is 0.05 to 1.0% by weight.
A photographic resin-coated paper according to claim 1. 3. The photographic resin-coated paper according to claim 1 or 2, wherein the titanium dioxide is surface-treated with an inorganic surface treatment agent prior to the polyether-modified siloxane surface treatment. 4. The photographic resin-coated paper according to claim 1, 2, or 3, wherein the inorganic surface treatment agent is hydrated aluminum oxide. 5 The amount of inorganic surface treatment agent treated is 0.2 to 1.2% by weight, preferably 0.2 to 0.6% by weight based on titanium dioxide.
(calculated in anhydrous form) Photographic resin coated paper according to claim 1, 2 or 3. 6. Claims 1 and 2, in which the amount of hydrous aluminum oxide treated is 0.2 to 1.2% by weight, preferably 0.2 to 0.6% by weight (calculated in the form of Al ₂ O ₃ ), based on titanium dioxide. , the photographic resin-coated paper according to item 3 or 4. 7 Claims 1, 2, 3, 4, 5, or 6 in which the resin is a thermoplastic resin
Photographic resin-coated paper as described in Section 1. 8. The photographic resin-coated paper according to claim 7, wherein the thermoplastic resin is a polyolefin resin. 9. The photographic resin-coated paper according to claim 8, wherein the polyolefin resin is a polyethylene resin. 10. The photographic resin-coated paper according to claim 1, wherein the resin composition contains a fatty acid metal salt. 11 The content of fatty acid metal salt in the resin composition is
11. The photographic resin-coated paper according to claim 10, wherein the amount is 0.1 to 5.0% by weight based on the titanium dioxide pigment.