JP4616629B2 - Method for producing support for imaging material - Google Patents

Description

  The present invention relates to a support for image material in which both sides of a paper substrate (hereinafter sometimes abbreviated as base paper) mainly composed of natural pulp are coated with a polyolefin resin, and more specifically, a molten resin. It is related to a support for imaging materials that can be peeled off from the cooling roll when coated on the base paper surface and the lip stain of the extruder is small, so that a homogeneous image surface can be obtained and stable high-speed production can be achieved. is there.

  2. Description of the Related Art Conventionally, a resin-coated paper image material support in which a base paper surface for the image material support is coated with a resin capable of forming a film is well known. For example, a technique relating to a support for image material in which both surfaces of a base paper are coated with a polyolefin-based resin is disclosed (for example, see Patent Document 1). Since the rapid development of silver halide photosensitive materials, photographic papers with both sides of the base paper coated with polyolefin resin have been put to practical use. Today, there are a wide variety of image output types. Accompanying this trend, various image receiving layers are provided on a support for image material, so that they are widely used as various image receiving papers for thermal transfer, ink jet, electrophotography and the like (for example, see Patent Document 2).

  In many cases, the support for an image material usually contains a titanium dioxide pigment in a resin layer for the purpose of enhancing the sharpness of an image output to the image material (see, for example, Patent Document 3). When a pigment such as titanium dioxide is blended in the resin layer, various additives are added to improve the dispersibility of the pigment, processing suitability, etc. In general, metal soap is used as a lubricant. . However, although metal soap exerts its effect when added in an appropriate amount, it has been found that, in continuous operation, itself causes contamination of rolls and the like due to the effects of thermal decomposition and the like. In particular, the cooling roll with which the melted resin is in direct contact is likely to be contaminated with a soil composed mainly of a metal soap decomposition product, and the soil tends to accumulate as the continuous operation time increases.

  If a large amount of dirt on the cooling roll begins to occur during production, the peelability from the cooling roll deteriorates and the tendency of the resin layer to be removed on the cooling roll side increases, resulting in unevenness on the smooth resin layer surface. start. The unevenness causes a serious quality failure because it reduces the surface smoothness of the image material support.

Further, when the molten resin is applied to the base paper surface, the molten resin is cast and applied in the form of a film from a slit die. (Hereinafter, sometimes referred to as die lip dirt) tends to adhere. When die lip dirt adheres, it causes the occurrence of vertical streak-like unevenness on the surface of the resin film, and the image material support thus obtained has the surface homogeneity significantly impaired.
U.S. Pat. No. 3,501,298 JP 2002-294599 A JP 2000-241935 A

Accordingly, an object of the present invention is to provide a support for an image material in which both sides of a base paper containing natural pulp as a main component are coated with a polyolefin resin. Further, the present invention provides a method for producing a support for image material that can obtain a homogeneous image surface and can stably produce at a high speed because the die lip contamination of the extruder is small.

As a result of intensive studies to solve the above problems, the present inventors have found the following present invention. That is, the first invention is a method for producing a support for an image material in which both surfaces of a base paper are coated with a polyolefin-based resin layer, and the side on which an image forming layer is provided (hereinafter sometimes referred to as the front side). The resin layer comprises a resin composition in which at least two master batches , a master batch using a metal soap containing at least zinc as a lubricant and a master batch using a metal soap containing calcium or lithium as a lubricant, are mixed. And a method for producing a support for image material.

2nd invention is a manufacturing method of the support body for image materials whose total amount of the metal soap in the resin composition in 1st invention is 0.1 mass% to 1.0 mass%.

A third invention is an invention of a method for producing a support for imaging material, wherein the ratio of zinc-based metal soap is 25 mol% to 75 mol% in the metal soap in the resin composition in the first or second invention. It is.

The present invention relates to a method for producing a support for an image material in which both surfaces of a base paper containing natural pulp as a main component are coated with a polyolefin resin, wherein the resin layer on the side where the image forming layer is provided is a metal containing at least zinc The molten resin composition is applied to the base paper surface by using a resin composition in which at least two master batches of a master batch using soap as a lubricant and a master batch using metal soap containing calcium or lithium as a lubricant are used. In this case, it is possible to provide a method for producing a support for imaging material, which has good peelability from a cooling roll and less die lip contamination of an extruder, so that a homogeneous image surface can be obtained and high-speed production can be stably performed. it can.

As described above, the present invention suppresses the occurrence of cooling roll stains and die lip stains, and provides a method for producing a support for imaging material having a uniform surface. It has been clarified that one factor that worsens the cooling roll stain and the die lip stain is the decomposition of the metal soap contained in the polyolefin resin layer. That is, when a polyolefin resin containing a metal soap having low heat resistance is extruded from a slit die into a film state using a melt extruder, these substances are thermally decomposed because they are extruded at a high temperature. As a result, a sticky denatured product is formed, and this cohesive denatured product is deposited on the chill roll, causing chill roll contamination. On the other hand, when the molten resin is extruded from the slit die, the pyrolysis substance adheres to the tip portion of the die lip to form ice column-shaped die lip dirt.

  Since the metal soap is a metal salt of a higher fatty acid, it is known that its heat resistance and properties as a lubricant change variously by changing the type of the fatty acid and the metal. In general, the processing lubricity of lubricants can be divided into internal lubrication and external lubricity, making it easy to mix resin and additives such as pigments uniformly, preventing friction that occurs locally between molecules, The action of improving the fluidity so as to be easily extruded from the melt extruder is referred to as internal lubricity. On the other hand, the effect of preventing the resin from sticking to a processing machine or the like at the temperature at the time of melt processing is called external slip. The functions of these metal soaps vary depending on the type of base resin to which the metal soap is added. Particularly, polyolefin resins exhibit internal lubricity when the metal is lithium, calcium, etc., and zinc is an external lubrication. Great effect as sex.

  As the metal species in the metal soap, zinc is generally used, but by changing to lithium, calcium, magnesium, or aluminum, etc., the heat resistance of the metal soap is improved. It is one of the effective means to use these as countermeasures against die lip contamination. It has also been found that a certain effect can be obtained when a composite in which a plurality of the above-mentioned lubricants are mixed is used as the lubricant.

  However, in the present invention, in the present invention, when using a lubricant with a different metal species alone or when using a composite of different types of metal soaps as a lubricant, the writer is more excellent in resistance to cooling roll and die lip. A resin formulation was found. That is, the object is achieved by making the resin layer on the front side a resin composition in which a master batch using a metal soap containing at least zinc and a metal soap containing calcium or lithium as a lubricant is mixed. It came to.

  The total amount of metal soap contained in the resin composition is preferably in the range of 0.1% by mass to 1.0% by mass, and more preferably between 0.2% by mass and 0.6% by mass. When the lubricant content is too small, the releasability from the cooling roll is insufficient, and when it is too much, dirt is generated due to excessive lubricant bleed out.

  Of the two types of metal soap blended in the resin composition, the ratio of the zinc-based metal soap is preferably in the range of 25 mol% to 75 mol%. When the zinc-based metal soap ratio is too high, heat resistance cannot be improved. When the zinc-based metal soap ratio is too low, the function of external lubrication is insufficient, so that cooling roll dirt and die lip dirt are not reduced.

  The metal other than zinc, lithium and calcium used in the present invention is not particularly limited as long as the effects of the present invention are not impaired, and magnesium, aluminum, and the like can be used.

  Further, the type of fatty acid in the metal soap used in the present invention is not particularly limited as long as it does not inhibit the effect of the present invention, and stearic acid, palmitic acid, montanic acid, behenic acid and the like can be used. Any combination of fatty acids may be used. In particular, in order to provide heat resistance as a metal soap, it is preferable to use a fatty acid having 14 or more carbon atoms. Furthermore, in the present invention, a fatty acid having a hydroxyl group can be used. For example, as the metal soap using 12-hydroxystearic acid, lithium 12-hydroxystearate, calcium 12-hydroxystearate, zinc 12-hydroxystearate and the like are preferably used.

As the polyolefin resin to be coated on the side on which the image constituent layer of the base paper for the image material support in the present invention is provided, low density polyethylene, medium density polyethylene, high density polyethylene, linear low density polyethylene, or a mixture thereof Is preferred. Among them, various densities, melt flow rates (hereinafter simply abbreviated as MFR), molecular weight, and molecular weight distribution can be used. Usually, the density is in the range of 0.90 to 0.97 g / cm ³ and the MFR is 0. 0.1-50 g / 10 min, preferably those having a MFR in the range of 0.3-40 g / 10 min can be used advantageously alone or in admixture. When the resin has a multi-layer structure, for example, the outermost layer resin having an MFR of 5 to 20 g / 10 minutes, the lower layer resin having an MFR of 2 to 10 g / 10 minutes, etc. Resins having other properties and configurations can also be used.

  In the present invention, the coating thickness of the polyolefin resin that covers the surface on which the image-constituting layer of the base paper for the image material support is provided is useful in the range of 4 to 70 μm, preferably in the range of 6 to 45 μm. The range of 9 to 35 μm is particularly preferable.

  Various pigments such as titanium dioxide can be contained in the polyolefin resin layer covering the surface of the support for image material in the present invention on the side on which the image constituting layer is provided. As a method of incorporating the titanium dioxide pigment into the polyolefin resin, a so-called master batch in which the titanium dioxide pigment is previously contained in the polyolefin resin at a predetermined concentration is prepared, and mixed in a desired ratio with the polyolefin resin for dilution. Dilute and use. When producing this masterbatch, it is preferable to contain various metal soaps in order to improve the dispersibility of the titanium dioxide pigment.

  In order to produce these master batches, a Banbury mixer, a kneader, an extruder for kneading, a roll kneader, or the like can be usually used, and two or more of these various kneaders may be used in combination.

As the polyolefin resin used for the preparation of a masterbatch composed of these titanium dioxide pigment and polyolefin resin, those having suitable physical properties relating to the kneadability of the titanium dioxide pigment and polyolefin resin are preferable. Specifically, a low-viscosity polyolefin resin or a medium-viscosity polyolefin resin having a density in the range of 0.917 to 0.925 g / cm ³ and an MFR of ³ to 12 g / 10 minutes is preferable.

  In preparing a polyolefin resin composition comprising a titanium dioxide pigment and a polyolefin resin, it is preferable to prepare the polyolefin resin composition in the presence of an appropriate amount of an antioxidant. Specifically, hindered phenol-based antioxidants described or exemplified in JP-A-1-105245, hindered amines, sulfur other than phosphorus-based antioxidants described or exemplified in JP-A-55-142335. An appropriate amount of various antioxidants such as a system is preferably present, but it is particularly preferable that an appropriate amount of a hindered phenol-based antioxidant is present. The amount of the antioxidant present in the preparation of these polyolefin resin compositions is preferably as small as possible for the above reasons, but is preferably in the range of 50 to 3000 ppm, and more preferably in the range of 50 to 1000 ppm.

  In the present invention, the polyolefin resin that covers the surface of the image material support on which the image constituting layer is provided may contain various additives in addition to the titanium dioxide pigment, the metal soap, and the antioxidant. White pigments such as zinc oxide, talc and calcium carbonate, fatty acid amides such as stearic acid amide and arachidic acid amide, blue pigments and dyes such as cobalt blue, ultramarine blue, ceria blue and phthalocyanine blue, cobalt violet, fast violet, manganese Various additives such as magenta pigments and dyes such as violet, fluorescent whitening agents and ultraviolet absorbers described or exemplified in JP-A-2-254440 can be appropriately combined and contained.

  The base paper surface opposite to the side on which the image constituting layer of the support for image material in the present invention is provided is coated with a film-forming resin containing at least a polyolefin-based resin. As the resin capable of forming a film other than the polyolefin-based resin, thermoplastic resins such as polycarbonate resin, polyester resin, and polyamide resin are preferable, and the above-described polyethylene resin is particularly preferable from the viewpoint of melt extrusion coating property.

  In the resin coating layer having a film forming ability on the base paper surface opposite to the side on which the image constituting layer of the support for image material of the present invention is provided, in the same manner as the polyolefin resin layer on the side on which the image constituting layer is provided, a white pigment, fatty acid amide , Fatty acid metal salts, various antioxidants, blue pigments and dyes, magenta pigments and dyes, fluorescent whitening agents, ultraviolet absorbers, and other various additives may be included in appropriate combinations.

  Further, the surface of the image material support opposite to the side on which the image forming layer is provided is preferably a resin similar to the resin on the front side, and the coating thickness is particularly balanced with the resin on the front side. It is preferable to set appropriately within the range, and generally a range of 4 to 70 μm is useful, preferably a range of 6 to 45 μm, and particularly preferably a range of 9 to 35 μm.

  The image material support of the present invention is characterized in that it can be processed at a higher speed. In order to provide a fixed amount of the coating resin layer on the base paper surface as the traveling speed during processing increases, the number of extrusions of the molten resin must be increased by increasing the number of rotations of the extrusion screw. Therefore, as the traveling speed is increased, the shear stress of the molten resin increases, and as a result, the frequency of occurrence of cooling roll stains and die lip stains accompanying the promotion of resin deterioration increases. At a traveling speed in a relatively low speed region of 150 m / min or less, there are cases where the frequency of occurrence increases as the traveling speed increases even though the frequency of occurrence of cooling roll dirt and die lip dirt is low. In the present invention, processing at a higher speed is possible. Specifically, the effect appears at 200 m / min or more, and stable workability can be maintained even at 400 m / min or more.

  As a method of coating the resin on the base paper surface of the image material support in the present invention, the resin composition is cast on the traveling base paper using a melt extruder, and is coated in a film form from the slit die. It is preferable to coat by the so-called melt extrusion coating method. In that case, it is preferable that resin temperature is 270 degreeC-350 degreeC. By this range, it becomes especially favorable about adhesiveness, resin deterioration prevention, and a homogeneous surface quality.

  The slit die is preferably a flat die such as a T-type die, an L-type die, or a fishtail die, and the slit opening diameter is preferably 0.1 to 2 mm. Moreover, it is preferable to subject the base paper to activation treatment such as corona discharge treatment and flame treatment before coating the resin composition on the base paper. Also, the resin layer can be coated on the base paper that travels after the ozone-containing gas is sprayed on the molten resin composition in contact with the base paper described or exemplified in Japanese Patent Publication No. 61-42254. Moreover, it is preferable to coat the base paper by a so-called tandem extrusion coating method in which the front and back resin layers are extrusion-coated sequentially or continuously.

  Further, the surface resin layer side of the image material support on which the image constituting layer is to be coated is processed into a glossy surface, fine rough surface, matte surface or silky surface as described in JP-B-62-19732. In general, it is preferable to process the back resin layer on the opposite side to a matte surface.

  The titanium dioxide pigment used in the present invention is preferably a surface treated with an organic substance. Examples of organic substances used for the surface treatment include onoganopolysiloxane compounds such as dimethylpolysiloxane, dimethylphenylpolysiloxane, and methylhydrogenpolysiloxane described or exemplified in Japanese Patent Publication No. 61-26652, and Japanese Patent Publication No. 60-3430. A silane coupling agent such as alkyltrimethoxysilane or γ-aminopropyltriethoxysilane described in or exemplified above, a polyhydric alcohol compound such as trimethylolethane or trimethylolpropane described or exemplified in JP-B-3-35652, Examples thereof include alkanolamine compounds such as triethanolamine and triisopropanolamine, or inorganic salts thereof, but it is more preferable to use a titanium dioxide pigment treated with a silane coupling agent.

  The treatment amount of these organic surface treatment agents is preferably as small as possible for the reasons described above, but is preferably in the range of 0.05 to 2.5% by mass with respect to the titanium dioxide pigment, 0.05 to The range of 1.5% by mass is more preferable.

  The titanium dioxide pigment used in the practice of the present invention may be surface treated with an inorganic substance such as hydrous aluminum oxide or hydrous silicon oxide before being surface treated with an organic substance. In that case, appropriate processing as described or exemplified in Japanese Patent Publication No. 63-11655, Japanese Patent Publication No. 1-38291, Japanese Patent Publication No. 1-38292, Japanese Patent Publication No. 1-105245 is performed. It is preferable.

  The base paper mainly composed of natural pulp used in the present invention includes normal bleaching treatment such as chlorine, hypochlorite, chlorine dioxide bleaching, and alkali extraction or alkali treatment, and hydrogen peroxide as necessary. , Wood pulp of softwood pulp, hardwood pulp, mixed softwood hardwood pulp that has been subjected to oxidative bleaching treatment with oxygen, etc., and combinations thereof, and various types such as kraft pulp, sulfite pulp, soda pulp, etc. Can be used.

  The base paper used in the present invention can contain various additives at the time of preparing the paper slurry. As sizing agent, fatty acid metal salt or fatty acid, alkyl ketene dimer emulsion described or exemplified in JP-B-62-7534, epoxidized higher fatty acid amide, alkenyl or alkyl succinic anhydride emulsion, rosin derivative, etc., dry paper Anionic, cationic or amphoteric polyacrylamide, polyvinyl alcohol, cationized starch, vegetable galactomannan, etc. Calcium, titanium dioxide, etc., fixing agents such as water-soluble aluminum salts such as aluminum chloride and sulfuric acid bands, etc., pH regulators such as caustic soda, sodium carbonate, sulfuric acid, etc., other JP-A-63-204251, JP-A-1 -266537 Colored pigment according or exemplified in Japanese, colored dye, that allowed to contain in combination as appropriate fluorescent whitening agent is advantageous.

  In addition, a composition comprising various water-soluble polymers or hydrophilic colloids or latexes, antistatic agents, and additives is applied to the base paper used in the practice of the present invention by size press or tab size press or blade coating. It can be contained or applied by coating such as coating or air knife coating. As a water-soluble polymer or hydrophilic colloid, starch-based polymer, polyvinyl alcohol-based polymer, gelatin-based polymer, polyacrylamide-based polymer, cellulose-based polymer, etc. described or exemplified in JP-A-1-266537 can be used as emulsions and latexes. Petroleum resin emulsion, emulsion or latex of copolymer comprising at least ethylene and acrylic acid (or methacrylic acid) as described or exemplified in JP-A-55-4027 and JP-A-1-180538, styrene -Emulsions or latexes of butadiene, styrene-acrylic, vinyl acetate-acrylic, ethylene-vinyl acetate, butadiene-methyl methacrylate copolymers and their carboxy-modified copolymers, etc. Examples of the inhibitor include alkali metal salts such as sodium chloride and potassium chloride, alkaline earth metal salts such as calcium chloride and barium chloride, colloidal metal oxides such as colloidal silica, and organic antistatic agents such as polystyrene sulfonate. , Pigments such as clay, kaolin, calcium carbonate, talc, barium sulfate, titanium dioxide, etc., pH regulators such as hydrochloric acid, phosphoric acid, citric acid, caustic soda, etc. It is advantageous to contain these additives in appropriate combinations.

The thickness of the base paper used in the present invention is not particularly limited, but the basis weight is preferably 50 to 250 g / m ² .

  In the present invention, the surface of the polyolefin resin layer on the side where the image constituting layer of the support for image material is provided can be subjected to activation treatment such as corona discharge treatment or flame treatment. Further, after the activation treatment, the undercoat layer treatment described or exemplified in JP-A-1-102551, JP-A-1-166035 and the like can be performed.

  On the back resin layer surface of the support for image material in the present invention, various back coat layers can be applied for antistatic purposes after performing activation treatment such as corona discharge treatment and flame treatment. . In addition, the back coat layer includes JP-B-52-18020, JP-B-57-9059, JP-B-57-53940, JP-B-58-56859, JP-A-59-214849, JP-A-58-184144. An inorganic antistatic agent, an organic antistatic agent, a hydrophilic binder, latex, a curing agent, a pigment, a surfactant, and the like described or exemplified in each publication such as No. 1 can be contained in appropriate combinations.

  The image material support in the present invention is coated with various image forming layers, for color photographic printing paper, for black and white photographic printing paper, for phototypesetting printing paper, for electronic phototypesetting printing paper, for laser light sensitive printing paper, It can be used in various applications such as for copying photographic paper, for reversal photographic materials, for silver salt diffusion transfer method negatives and positives, for printing materials, for thermal transfer image receiving paper, and for electrophotographic image receiving paper.

  For example, a silver chloride, silver bromide, silver chlorobromide, silver iodobromide, silver chloroiodobromide photosensitive emulsion layer can be provided. A multilayer silver halide color image constituting layer can be provided by incorporating a color coupler into the silver halide light-sensitive emulsion layer. Further, an image constituting layer for silver salt diffusion transfer method can be provided. As binders for these image-constituting layers, hydrophilic polymer substances such as polyvinyl pyrrolidone, polyvinyl alcohol, and polysaccharide sulfate compounds can be used in addition to ordinary gelatin.

  Moreover, various additives can be contained in the above-mentioned image forming layer. Examples include sensitizing dyes such as cyanine dyes and merocyanine dyes, chemical sensitizers such as water-soluble gold compounds and sulfur compounds, antifoggants or stabilizers such as hydroxy-triazolopyrimidine compounds and mercapto-heterocyclic compounds. Formalin, vinyl sulfone compounds, aziridine compounds, etc. as hardening agents, alkylbenzene sulfonates, sulfosuccinates, etc. as coating aids, other fluorescent brighteners, sharpness improving dyes, antistatic agents, pH adjusters Further, water-soluble iridium, a water-soluble rhodium compound and the like can be appropriately combined and contained during the production and dispersion of silver halide.

  The support for image material in the present invention can be used as a support for various ink jet recording materials by applying various ink image receiving layers. These ink image-receiving layers can contain various binders for the purpose of improving the drying property of the ink, the sharpness of the image, and the like. Specific examples of such binders include various types of gelatin such as lime-processed gelatin, acid-processed gelatin, enzyme-processed gelatin, gelatin derivatives such as gelatin reacted with dibasic acid anhydrides such as phthalic acid, maleic acid, and fumaric acid. , Normal polyvinyl alcohol of various saponification degrees, carboxy-modified, cation-modified and amphoteric polyvinyl alcohol and derivatives thereof, starches such as oxidized starch, cationized starch and etherified starch, cellulose derivatives such as carboxymethylcellulose and hydroxyethylcellulose , Polyvinyl pyrrolidone, polyvinyl pyridium halide, sodium polyacrylate, methacrylic acid copolymer salt, polyethylene glycol, polypropylene glycol, polyvinyl ether, alkyl vinyl ether-maleic anhydride copolymer , Styrene-maleic anhydride copolymer and salts thereof, synthetic polymer such as polyethyleneimine, conjugated diene copolymer latex such as styrene-butadiene copolymer, methyl methacrylate-butadiene copolymer, polyvinyl acetate, Vinyl acetate polymer latex such as vinyl acetate-maleic acid ester copolymer, vinyl acetate-acrylic acid ester copolymer, ethylene-vinyl acetate copolymer, acrylic acid ester polymer, methacrylic acid ester polymer, ethylene- Functional group such as acrylate group copolymer, acrylic polymer such as styrene-acrylate ester copolymer or latex of copolymer, vinylidene chloride copolymer latex, etc. or carboxyl group of these various polymers Functional group-modified polymer latex with monomer containing melamine Aqueous adhesives such as thermosetting synthetic resins such as fats and urea resins, and synthetic resin adhesives such as polymethyl methacrylate, polyurethane resins, unsaturated polyester resins, vinyl chloride-vinyl acetate copolymers, polyvinyl butyral, alkyd resins, etc. Inorganic binders such as alumina sol and silica sol described or exemplified in JP-B-3-24906, JP-A-3-281383, JP-A-6-92011, and the like can be mentioned alone or in combination. It can be used in combination.

  The ink image-receiving layer of the ink jet recording material according to the present invention can contain various additives in addition to the binder. For example, as a surfactant, an anionic surfactant such as a long chain alkylbenzene sulfonate, a long chain, preferably a branched alkylsulfosuccinate, a polyalkylene oxide of a long chain, preferably a branched alkyl group-containing phenol Nonionic surfactants such as ethers and polyalkylene oxide ethers of long-chain alkyl alcohols, fluorinated surfactants described in JP-B-47-9303, US Pat. No. 3,589,906, etc. Silane coupling agents such as ethoxysilane, N-β- (N-vinylbenzylaminoethyl) -γ-aminopropyltrimethoxysilane, polymer hardeners, active halogen compounds, vinyl sulfone compounds, aziridine compounds, epoxy compounds , Acryloyl compound As a hardening agent such as an isocyanate compound, and a preservative, a p-hydroxybenzoate compound, a benzisothiazolone compound, an isothiazolone compound, etc. described or exemplified in JP-A-1-102551, JP-A 63-204251, As an ultraviolet absorber such as hydroxymethane sulphonate soda, p-toluene sulphonate soda, etc. as a yellowing inhibitor, such as colored pigments, colored dyes, fluorescent brighteners, etc. described or exemplified in Kaihyo 1-266537 etc. , A benzotriazole compound having a hydroxy-di-alkylphenyl group at the 2-position, an antioxidant, a polyhindered phenol compound described or exemplified in JP-A-1-105245, a pencil writing agent, a starch granule, Organic or inorganic particles such as barium sulfate and silicon dioxide 0.2 μm to 5 μm microparticles, organopolysiloxane compound described or exemplified in JP-B-4-1337, etc., as pH adjuster, caustic soda, sodium carbonate, sulfuric acid, hydrochloric acid, phosphoric acid, citric acid, octyl alcohol, Various additives such as a silicon-based antifoaming agent can be appropriately combined and contained.

  The image material support in the present invention can be used as various electrophotographic recording material supports coated with various toner image-receiving layers. These toner images can contain various binders, antistatic agents, pigments and the like for the purpose of improving the image density, toner fixability, transportability and the like. Specific examples of the binder include polyester resins, polyacrylate resins, polycarbonate resins, polyvinyl acetate resins, polyvinyl butyral resins, styrene-acrylate resins, resins having ester bonds such as vinyl toluene-acrylate resins, polyurethane resins, and the like. Resin having urethane bond, resin having amide bond such as polyamide resin, resin having urea bond such as urea resin, other polycaprolactam resin, styrene resin, polyvinyl chloride resin, vinyl chloride-vinyl acetate copolymer resin, Examples thereof include polyacrylonitrile resin. In addition to these resins, mixtures or copolymers thereof can also be used. Specific examples of the antistatic agent are not particularly limited, and various antistatic agents can be used. For example, fatty acid salts, sulfate ester salts, sulfate salts of aliphatic amines and aliphatic amides, phosphate ester salts, sulfonate salts, aliphatic amine salts, quaternary ammonium salts, and betaine amphoteric salts, imidazoline amphoteric salts Examples of the metal oxide include zinc oxide, titanium dioxide, tin oxide, aluminum oxide, magnesium oxide, and barium oxide. Specific examples of the pigment are not particularly limited, but various inorganic and organic pigments such as clay, talc, kaolin, aluminum hydroxide, potassium carbonate, titanium dioxide, barium sulfate, zinc oxide, satin white, plastic pigment, etc. Coating pigments can be used. Moreover, a mold release agent, a plasticizer, surfactant, dye, etc. can be suitably combined and contained as needed.

  EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, the content of this invention is not restricted to an Example.

(Examples 1 to 10)
After beating mixed pulp consisting of hardwood bleached kraft pulp, hardwood bleached sulfite pulp and softwood bleached sulfite pulp so that freeness (CSF) becomes 350 ml, cationized starch, anionized polyacrylamide, alkyl ketene dimer emulsion, polyamide A stock slurry was prepared by adding epichlorohydrin resin, fluorescent brightener, blue dye and red dye.

  After that, the stock slurry is placed on a long paper machine running at 200 m / min, and a web is formed while giving an appropriate turbulence, and the linear pressure is in the range of 15 kN / m to 100 kN / m in the wet part. After performing the adjusted three-stage wet press, after processing with a smoothing roll, and after performing the two-stage machine calendar process in which the linear pressure was adjusted in the range of 30 kN / m to 70 kN / m in the subsequent drying part, Dried.

Then, a size press solution consisting of carboxy-modified polyvinyl alcohol, fluorescent whitening agent, blue dye, sodium chloride and water was pressed at 25 g / m ² size in the middle of drying. It was dried to 8 mass% and machine calendered under the condition of a linear pressure of 50 kN / m to produce a base paper for an image material support having a basis weight of 170 g / m ² .

Next, after the corona discharge treatment was performed on the base paper surface (back surface) opposite to the side on which the image forming layer is provided, 35 parts by mass of low density polyethylene resin (density 0.92 g / cm ³ , MFR = 2 g / 10 min) A compound resin composition comprising 65 parts by mass of a high density polyethylene resin (density 0.96 g / cm ³ , MFR = 20 g / 10 min) was melted at a resin temperature of 320 ° C. to a thickness of 28 μm at a running speed of the base paper of 300 m / min. Extrusion coated.

Next, low-density polyethylene resin (density 0.92 g / cm ³ ; MFR = 8.5 g / 10 min) is mixed with anatase-type titanium dioxide, antioxidant and metal soap, and the titanium dioxide concentration is adjusted to 50% by mass. The master batch was prepared, and the master batch was blended with a low-density polyethylene resin for dilution having a density of 0.92 g / cm ³ and MFR = 4.5 g / 10 minutes to obtain a resin composition for extrusion coating. Moreover, the titanium dioxide in the resin composition was adjusted to 12% by mass. Subsequently, after the front side of the base paper was subjected to corona discharge treatment, the resin composition was extrusion coated at a resin temperature of 315 ° C. to a thickness of 30 μm at a running speed of the base paper of 300 m / min.

  The metal soap to be contained in the master batch is the one shown in Table 1, and the type and blending ratio (mass) of the metal soap in the resin composition for extrusion are the values shown in Examples 1 to 10 in Table 2. Adjusted. In addition, the front side of the resin layer of the resin-coated paper was processed into a glossy surface, and the surface quality of the resin layer on the back side was processed into a matte surface such as paper.

Furthermore, after the corona discharge treatment on the back resin surface of the resin-coated paper, the following back coat coating solution was applied on-machine. As a dry weight, a backcoat coating solution comprising a colloidal silica: styrene-based latex = 1: 1 and further containing an appropriate amount of a coating aid of polystyrene sulfonate sodium 0.021 g / m ² is used as a latex component (solid mass). As a result of calculation, it was coated at a coating amount of 0.21 g / m ² to obtain a support for image material.

(Comparative Examples 1-3)
Except for adjusting the type and blending ratio of the metal soap contained in the resin composition covering the base paper surface on the front side to the blending shown in Comparative Examples 1 to 3 in Table 2, the same as in Example 1, for image materials A support was obtained.

(Comparative Example 4)
A support for imaging material in the same manner as in Example 1 except that the type and blending ratio of the metal soap contained in the resin composition covering the base paper surface on the front side are adjusted to the blending shown in Comparative Example 4 in Table 2. Got. However, the two types of metal soaps were used as a premixed composite.

(Comparative Examples 5-6)
Except for adjusting the types and blending ratios of the metal soaps contained in the resin composition covering the base paper surface on the front side to the blends shown in Comparative Examples 5 to 6 in Table 2, the same as in Example 1, for image materials A support was obtained.

  Table 2 shows the image clarity of the image material support obtained as described above, and the evaluation results of the peelability of the polyethylene resin composition and the cooling roll and the die lip stains during production. In addition, each evaluation was performed by the method shown below.

[Peelability]
The peelability of the polyolefin resin composition on the front side and the cooling roll was evaluated by measuring the peel angle shown in FIG. The peel angle was measured 8 hours after the start of production, and the judgment criteria were as follows.
A: The peel angle is 0 ° to less than 1 °, and the peelability is very good.
○: The peel angle is 1 ° to less than 3 °, which is good.
(Triangle | delta): A peel angle is 3 degrees-less than 5 degrees, and peelability falls a little.
X: Peeling angle is 5 ° or more, and peeling is poor.

[Die lip dirt]
Eight hours after the start of melt extrusion, the tip of the die lip was observed to visually determine the state of occurrence of ice column-like dirt. Judgment criteria are as follows.
(Double-circle): Die lip dirt is hardly seen and it is very good.
○: Die lip contamination is small and good.
Δ: Die lip smudges occur sparsely, but practically acceptable.
X: Die lip stains are frequently generated, and there are practical problems.

[Image clarity]
The image quality measuring device ICM-2DP type manufactured by Suga Test Instruments Co., Ltd. was used, and the support for image material coated with a resin using an optical comb width of 2 mm was evaluated. The evaluation criteria are as follows.
A: Image clarity is very good.
○: Good image clarity.
Δ: Image clarity is slightly inferior, but is in a practically acceptable range.
X: The image clarity is poor and there is a problem in practical use.

<Result evaluation>
As can be seen from Table 2, since Examples 1 to 10 are metal soap formulations in the preferred range of the present invention, the peelability is good and the occurrence of die lip contamination is small, so that sufficient surface smoothness is obtained. It is obtained and shows good image clarity. The total amount of metal soap was the upper and lower limits of Example 1 and Example 10, and the mixing ratio of zinc-based metal soap was the limit of Examples 8 and 9. In the case of Comparative Examples 1 to 3 using metal soap alone or Comparative Example 4 using a composite lubricant premixed with metal soap, sufficient peelability cannot be obtained and die lip stains frequently occur. As a result, the surface smoothness of the material support was significantly impaired. In Comparative Examples 5 and 6, a metal soap having magnesium and aluminum was used, but the combination of these and zinc stearate did not exhibit the effect of the present invention.

(Examples 11 to 16)
Except for adjusting the types and blending ratios and running speeds of the metal soaps contained in the resin composition covering the front side base paper surface to the blends shown in Examples 11 to 16 in Table 3, the same as in Example 1 A support for imaging material was obtained.

(Comparative Example 7)
Except for adjusting the type and blending ratio of metal soap contained in the resin composition covering the base paper surface on the front side, the total amount of metal soap added, and the running speed to the blending shown in Comparative Example 7 in Table 3, Examples In the same manner as in Example 1, an image material support was obtained.

(Comparative Example 8)
Image material in the same manner as in Example 1 except that the type, blending ratio and running speed of the metal soap contained in the resin composition covering the front side paper surface are adjusted to the blending shown in Comparative Example 8 in Table 3. A support was obtained. However, the two types of metal soaps were used as a premixed composite.

  Table 3 shows the image clarity of the image material support obtained as described above, and the evaluation results of the peelability of the polyethylene resin composition and the cooling roll and the die lip stains during production. Each evaluation was performed in the same manner as in Example 1.

<Result evaluation>
As can be seen from Table 3, Examples 11 to 14 have a metal soap prescription within a preferred range in the present invention, so that the peelability is good and the occurrence of die lip contamination is small, so that the good image clarity is impaired. It was possible to increase the processing speed to 400 m / min. Furthermore, it was found that processing up to 450 m / min was possible by applying the metal soap formulation shown in Examples 15 and 16. As in Comparative Examples 7 and 8, when a single metal soap was used or a composite lubricant by premixing was used, the die lip soiling deteriorated and good surface smoothness could not be obtained.

  The support for image material of the present invention is used for applications such as inkjet recording paper, electrophotographic transfer paper, photographic paper support, thermal recording paper, thermal transfer image-receiving paper, etc. As a support for image material conveyed to a printer device or a developing processor in the form of winding, high-speed and stable production can be achieved without impairing surface smoothness on the front side.

The conceptual diagram of the peeling angle at the time of peelability evaluation of this invention.

Explanation of symbols

1 Cooling roll 2 Press roll 3 Web 4 Peeling roll 5 Peeling angle

Claims (3)

A method for producing a support for an image material in which both surfaces of a base paper are coated with a polyolefin resin layer, wherein the resin layer on the side on which the image forming layer is provided is a master batch using a metal soap containing at least zinc as a lubricant, A method for producing a support for imaging materials, comprising a resin composition in which at least two master batches of a master batch using a metal soap containing calcium or lithium as a lubricant are mixed. The method for producing a support for an image material according to claim 1, wherein the total amount of the metal soap in the resin composition is 0.1% by mass to 1.0% by mass. The method for producing a support for imaging material according to claim 1 or 2, wherein the ratio of zinc-based metal soap to 25 mol% to 75 mol% of the metal soap in the resin composition.

Images