JPH0619520B2 - Water resistant photographic paper support - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a water resistant photographic printing paper support. More specifically, the present invention relates to a water-resistant photographic printing paper support having an electron beam curable resin coating layer provided on one or both sides of a base paper.

At present, as a photographic support for water-resistant photographic paper for color photography or black-and-white photography, a support having both sides of the paper coated with a polyolefin layer and having a photosensitive silver halide emulsion layer on at least one side of the coated surface. Is used. The polyolefin coating layer generally contains a highly light-reflecting white pigment such as titanium dioxide and optionally a tinting dye or a fluorescent whitening agent, the composition of which is the photographic image obtained. The sharpness of is important.

On the other hand, as a method for coating the paper with the polyolefin, the molten polyolefin is extruded from a T-die of an extruder into a film, extruded on a running paper, and the two are stuck together by a cooling roll and a press roll. The coating method is generally used.

However, in the case of the melt extrusion coating method of polyolefin, the dispersibility of the white pigment of polyolefin is poor, the content of the white pigment cannot be increased, and it is difficult to form a thin layer, resulting in poor production efficiency. Therefore, the concentration of the white pigment is usually 8 to 15% by weight of the polyolefin, and only a relatively low concentration can be produced.

Therefore, the photographic printing paper using the polyolefin-coated paper obtained by such a method has a drawback that the sharpness of the photographic image is low. This is because when the white pigment concentration is relatively low, some of the incident light rays on exposure are reflected on the surface of the polyolefin layer, but most of the light rays are scattered on the pigment particles away from the surface. This is because the sharpness of the photographic image is reduced.

Further, since the polyolefin is used in a molten state at about 300 ° C. during coating, the cellulose fiber on the surface is dehydrated by the rapid heating of the paper surface. Then, the surface of the paper is deformed due to the partial readjustment of the fibers which occurs after such rapid dehydration and cooling, which affects the smoothness.

In order to remedy these drawbacks of the polyolefin-coated photographic papers, they are water-resistant and have a high content of white pigments, which results in photographic images with high sharpness and controlled residual in the base paper. As a method for completely retaining water, JP-A-57-49946, JP-A-57-27257, JP-A-57-30830,
As described in JP-A-57-120934, a method has been proposed in which one side or both sides of a photographic base paper is coated with a white pigment-containing synthetic resin which is cured by an electron beam.

The synthetic resin binder which is cured by this electron beam is mainly composed of a resin having two carbon-carbon double bonds and a polymerizable resin such as acrylic acid ester and methacrylic acid ester of monovalent, divalent and trivalent alcohols. It is made of monomers.
However, when a resin containing a carbon-carbon double bond as described in JP-A-57-49946 (a urethane acrylate described in U.S. Pat. No. 4,092,173) is used, the photographic printing paper support is It spills, cracks, or turns yellow when exposed to sunlight.

It is considered that such a phenomenon is caused by the rapid curing of the resin by the electron beam, the large shrinkage of the resin during the curing, and the selection of the raw material used for the resin synthesis.

In view of such circumstances, the present inventors have found that the surface smoothness, flexibility, scratch resistance, warpage resistance and weather resistance are excellent, and the water resistance coated with a synthetic resin containing a high concentration of white pigment In order to obtain a photographic paper support, as a result of detailed examination of the compound having a carbon-carbon double bond, which is the composition raw material of the synthetic resin binder, it was found that the synthetic resin binder for synthetic resin coating was an aliphatic polyisocyanate and / or an oil. Polyisocyanate having an aromatic polyisocyanate as a main component (A), polyols containing polytetramethylene ether glycol and / or polycaprolactone polyol (B), and a unit amount containing active hydrogen and a carbon-carbon double bond Urethane resin containing carbon-carbon double bond obtained by reacting with body (C)
(I), and 15 (wt)% or more of white pigment are contained. If these are coated on the surface of the base paper and then polymerized and cured by electron beam irradiation, surface smoothness, flexibility, warpage resistance Found that it is possible to obtain a photographic printing paper support excellent in water resistance and scratch resistance and having a large white pigment content,
The present invention has been achieved.

The present invention will be described in more detail below.

The urethane resin (I) containing a carbon-carbon double bond used in the synthetic resin binder of the present invention is a polyisocyanate (A).
It is obtained by reacting a polyol (B), an active hydrogen and a monomer (C) containing a carbon-carbon double bond.

The polyisocyanate (A) is a polyisocyanate containing an aliphatic polyisocyanate and / or an alicyclic polyisocyanate as a main component, and examples of the aliphatic polyisocyanate include hexamethylene diisocyanate and lysine ethyl. Examples thereof include ester diisocyanate and tetramethylene diisocyanate.

Further, as the alicyclic polyisocyanate, 3-isocyanatomethyl-3,5,5-trimethylcyclohexyl-isocyanate (hereinafter abbreviated as isophorone diisocyanate), w, w'-diisocyanatodimethylcyclohexane, 4, 4'-methylenebis (cyclohexyl isocyanate) and the like.

Further, polyisocyanate having a terminal isocyanate obtained by reacting these isocyanate compounds with trimethylolpropane, water, etc. and dimerization reaction products and trimerization reaction products of these compounds are also included as the polyisocyanate of the present invention. Can be used.

Further, as the polyisocyanate (A), it is possible to use other aromatic diisocyanates together with the above-mentioned aliphatic polyisocyanate and alicyclic polyisocyanate in a range not exceeding 50% by weight. If the content of other aromatic diisocyanate exceeds 50% by weight, the weather resistance of the photographic paper support,
It is not preferable that the surface property is remarkably deteriorated.

Other aromatic diisocyanates that may be used include 2,4
-Tolylene diisocyanate, 2,6 tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate,
Examples thereof include naphthalene-1,5-diisocyanate.

Urethane resin containing carbon-carbon double bond of the present invention
The polyols (B) used in the production of (I) are polyols containing polytetramethylene ether glycol and / or polycaprolactone polyol.

Polytetramethylene ether glycol is obtained by ring-opening polymerization of tetrahydrofuran in the presence of a catalyst according to a known method, and in the present invention, the number average molecular weight thereof is 500.
Those in the range of up to 5000 can be used. A polytetramethylene ether glycol-based copolymer obtained by ring-opening polymerization of tetrahydrofuran and propylene oxide, ethylene oxide or the like at the same time can also be used.

Polycaprolactone polyol is produced by ring-opening polymerization of ε-caprolactone in the presence of a catalyst having the following polyhydric alcohol as an initiator according to a known method, but as the polycaprolactone polyol used in the present invention, Those having a number average molecular weight in the range of 250 to 5000 are used.

Examples of the polyhydric alcohol which is a polymerization initiator of ε-caprolactone include ethylene glycol, diethylene glycol, 1,2-propylene glycol, dipropylene glycol, 1,3-butanediol, 1,4-butanediol, 1,
Polymerization product of 6-hexanediol, neopentyl glycol, trimethylolpropane, glycerin, pentaerythritol, polytetramethylene ether glycol and polyhydric alcohols of these as initiators, ring-opening polymerization of ethylene oxide, propylene oxide, butylene oxide or Aliphatic polyhydric alcohols such as copolymerization products; cyclohexanedimethanol, cyclohexanediol, hydrogenated bisphenol A and polymerization products obtained by ring-opening polymerization of ethylene oxide, propylene oxide and butylene oxide using these glycols as an initiator, or Cyclohexyl group-containing polyhydric alcohols such as copolymerization products; bisphenol A, hydroquinone bis (2-hydroxyethyl ether), p-xylylene glycol, bis (β-
(Hydroxyethyl) terephthalate and ethylene glycol, propylene oxide,
Polyhydric alcohols containing an aromatic group such as a polymerization product or a copolymerization product to which butylene oxide is added; and a glycol having a carboxyl group such as dimethylolpropionic acid and diphenolic acid, and a third group such as N-methyldiethanolamine Polyhydric alcohols having various functional groups such as glycol having a primary amine can also be used.

In the present invention, the polyols (B) can use other polyols together with polytetramethylene ether glycol and polycaprolactone polyol, and the other polyols are urethane resins having a carbon-carbon double bond ( It can be used by mixing in a range of 0 to 80% by weight, preferably 0 to 60% by weight of the polyols used in the production of I).

When the content of polytetramethylene ether glycol and / or polycaprolactone polyol is less than 20% by weight of the used polyol, the photographic paper support coated with a synthetic resin has warpage resistance, flexibility, scratch resistance, and surface smoothness. It is not preferable because it has poor properties.

Polyols other than polytetramethylene ether glycol and polycaprolactone polyol which can be mixed and used have two or more active hydrogens in the molecule and usually have a molecular weight of 50 to 5,000 and are generally used for polyurethane production. Known polyhydroxy compounds such as low molecular weight polyols, polyethers, polyesters, polyacetals, polythioethers, polybutadienes having a hydroxyl group, acrylic polyols, epoxy polyols, oil-modified polyols, castor oil, etc. Is mentioned.

The low molecular weight polyols include ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, 1,3-butanediol, 1,4-butanediol, pentaethylene glycol, hexamethylene glycol, neopentyl glycol, and 2 -Ethyl-1,3-hexanediol, N-
Diols such as alkyldiethanolamine and bisphenol A are used. Further, a diol having a carboxyl group such as dimethylolpropionic acid may be partially mixed and used.

Also, low molecular weight polyhydric alcohols such as trimethylolpropane, trimethylolethane, pentaerythritol, glycerin, triethanolamine, triisopropanolamine, and an adduct of 1 mol of ethylenediamine and 4 mol of propylene oxide can be used.

Examples of polyethers include polymerization products or copolymerization products of ethylene oxide, propylene oxide and the like. Further, polyethers or mixed ethers obtained by condensation of the low molecular weight glycols, and products obtained by addition polymerization of these polyethers and the low molecular weight glycols with ethylene oxide and propylene oxide can also be used.

As polythioethers, it is particularly preferable to use thioglycol alone or a condensation product of thioglycol with other glycols.

Examples of the polyacetals include water-insoluble polyacetals obtained from 1,4-butanediol and formaldehyde or from 4,4'-dioxyethoxydiphenylmethane and formaldehyde.

Examples of polyesters include a reaction product obtained by a dehydration condensation reaction from a polybasic acid and a polyhydric alcohol. Examples of polybasic acids include succinic acid, adipic acid, phthalic acid, terephthalic acid, maleic acid, fumaric acid and their acid anhydrides, and examples of polyhydric alcohols include ethylene glycol, propylene glycol and 1,4-butanediol. , Neopentyl glycol, dipropylene glycol, trimethylolpropane, glycerin, pentaerythritol and the like.

As the monomer (C) containing active hydrogen and carbon-carbon double bond used for producing the urethane resin containing carbon-carbon double bond of the present invention, 2-hydroxyethyl acrylate and 2-hydroxyethyl methacrylate are used. , 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate, trimethylolpropane diacrylate and other (meth) acrylic acid hydroxyalkyl esters, crotonyl alcohol, allyl alcohol, cinnamic alcohol, unsaturated alcohols such as hydroxystyrene, Examples thereof include N-alkanol-substituted (meth) acrylamides such as N-methylol acrylamide, N-methylol methacrylamide, N-hydroxyethyl acrylamide and N-hydroxyethyl methacrylamide.

The urethane resin (I) containing a carbon-carbon double bond in the present invention is a polyisocyanate (A), a polyol (B) and a monomer containing an active hydrogen and a carbon-carbon double bond ( It is produced by reacting C), but this production reaction is essentially a reaction between an isocyanate group and a hydroxyl group, and is usually solvent-free or the presence of an organic solvent inert to the isocyanate group. Further, if necessary, the reaction is carried out at a temperature of 10 to 130 ° C., preferably 20 to 100 ° C. using a usual urethanization catalyst.

Further, a thermal polymerization inhibitor may be added in order to prevent the carbon-carbon double bond from reacting during urethanization, reaction or storage.

The above-mentioned polyisocyanate (A), polyols (B), active hydrogen and a monomer containing a carbon-carbon double bond (C) may be reacted at once, or they may be reacted individually in any order. You may let me.

The ratio of reacting these compounds can be arbitrarily selected according to the purpose, and the reaction method can be appropriately determined, but particularly preferable methods are shown below.

Polyisocyanate (A) and polyol (B) are reacted under an excess of isocyanate groups to obtain a polyurethane prepolymer having an isocyanate group at the terminal, and in contrast, this polyurethane prepolymer, active hydrogen and carbon-carbon A method for obtaining a urethane resin (I) having a carbon-carbon double bond by reacting a double bond-containing monomer (C) with an excess of hydroxyl groups with respect to an isocyanate group.

Another preferred production method is polyisocyanate (A)
And a monomer containing active hydrogen and a carbon-carbon double bond (C)
To give a modified isocyanate containing an isocyanate group and a carbon-carbon double bond, and then the modified isocyanate and the polyol (B) are reacted under the condition of excess hydroxyl groups to form a carbon-carbon double bond. Urethane resin containing
How to get (I).

Further, as another preferable production method, polyisocyanate is used.
(A) and the polyol (B) are reacted under conditions of excess isocyanate groups to obtain a polyurethane prepolymer having an isocyanate group at the terminal, and then the same or different polyol as the previously used polyol (B) is used. As a result, a chain extension reaction is carried out under an excess of hydroxyl groups to obtain a polyurethane prepolymer (a) having a hydroxyl group at the terminal. On the other hand, in a separate reaction vessel, polyisocyanate (A) is reacted with active hydrogen and a monomer (C) containing a carbon-carbon double bond to contain an isocyanate group and a carbon-carbon double bond. Modified isocyanate (b)
To get

Then, the polyurethane prepolymer (a) having a hydroxyl group at the terminal produced earlier and the modified isocyanate (b) are reacted under the condition of excess hydroxyl group to obtain a urethane resin (I) containing a carbon-carbon double bond. You can also

Furthermore, as another preferable production method, the polyisocyanate (A) and the polyol (B) are reacted in a ratio such that the polyisocyanate is 2 to 8 times equivalent to the polyol, and then the polyisocyanate remains in the reaction system. 0 per mole of isocyanate group.
After reacting 2 to 0.5 mol of active hydrogen with a monomer (C) containing a carbon-carbon double bond, and then using a polyol which is the same as or different from the polyol (B) used previously, under conditions of excess hydroxyl groups. A urethane resin (I) containing a carbon-carbon double bond may be obtained by a chain extension reaction.

Furthermore, as another preferred production method, a polyisocyanate (A) and a monomer (C) containing active hydrogen and a carbon-carbon double bond are added to the monomer (C). Two
The reaction is carried out at a ratio of about 8 times equivalent, and then 0.2 to 0.5 mol of the polyol (B) is reacted per 1 mol of the isocyanate group remaining in the reaction system.

Then, the same or different polyol as the previously used polyol is used to extend the chain under the condition of excess hydroxyl group, and
It is also possible to obtain a urethane resin (I) containing a carbon double bond.

As a solvent used in the production of the urethane resin (I) according to the present invention, an organic solvent inert to an isocyanate group such as acetone, methyl ethyl ketone, acetonitrile,
Dioxane, methyl isoptyl ketone, ethyl acetate, butyl acetate, toluene, xylene, cyclohexanone, dimethylformamide and the like can be mentioned. Further, a polymerizable monomer containing a carbon-carbon double bond which is inactive with respect to an isocyanate group, such as methyl acrylate, methyl methacrylate, ethylene glycol diacrylate, ethylene glycol dimethacrylate, trimethylolpropane triacrylate. Acrylic esters and methacrylic acid esters such as tetrahydrofurfuryl acrylate, styrene, vinyl acetate, vinylpyrrolidone, etc. can also be used as the solvent, and these are polymerized by electron beam irradiation with the urethane resin (I) after the reaction. Harden.

As the catalyst used in the urethanization reaction of the present invention, a usual urethanization catalyst, for example, dibutyltin dilaurate,
Dioctyl tin dilaurate, stanna octoate,
It is appropriately selected from tin-based catalysts such as dibutyltin diacetate and tertiary amine catalysts such as triethylenediamine and N-ethylmorpholine.

Examples of the thermal polymerization inhibitor used in the present invention include quaternary ammonium chlorides such as benzyltrimethylammonium chloride, diethylhydroxylamine and benzothiazole, lactic acid, benzoic acid, hydroquinone, hydroquinone monomethyl ether, t-butylpyrocatechol, and organic phosphines. , Phosphite and the like.

The synthetic resin binder in the present invention is a carbon-carbon double bond-containing urethane resin (I) unless it impairs its performance, acrylic resin, vinyl chloride resin, vinyl chloride-vinyl acetate copolymer, polyester resin, urethane. A thermoplastic resin such as a resin may be mixed and used, or a polymerizable monomer may be mixed and used. Methyl (meth) acrylate, (meth) as these polymerizable monomers
Ethyl acrylate, 2-ethylhexyl (meth) acrylate, phenoxy (meth) acrylate, glycidyl (meth) acrylate, 2-hydroxylethyl (meth) acrylate, 2-hydroxylpropyl (meth)
Acrylate, tetrahydrofurfuryl (meth) acrylate, mono (meth) acrylates such as (meth) acrylic acid; 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate,
Di (meth) acrylates such as polyethylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate and a reaction product of an adduct of bisphenol A and alkylene oxide with (meth) acrylic acid; trimethylolpropane Contains poly (meth) acrylates such as tri (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate; and carbon-carbon double bond Examples thereof include vinylpyrrolidone, styrene, vinyl acetate and the like. These polymerizable monomers can be used in the range of 0.2 to 3 times the amount of urethane resin (I).

The synthetic resin binder in the present invention is a carbon-carbon double bond-containing urethane resin (I), ethyl acetate, butyl acetate, methyl ethyl ketone, methyl isobutyl ketone, toluene, xylene, etc. which are generally used for this type of binder. It is also possible to use a mixture of the above organic solvents.

Known white pigments and fillers used in the present invention include, for example, titanium dioxide (rutile type and anatase type), barium sulfate, calcium carbonate, zinc sulfide, magnesium oxide, aluminum oxide, silicon dioxide and the like. To be Further, in some cases, dyes, inorganic colored pigments, organic colored pigments, glass fibers, antioxidants, antistatic agents, etc. may be added.

It is preferable that the white pigment and the filler added as necessary are contained in the coating layer in an amount of 15 to 60% by weight. If the amount is less than 15% by weight, the sharpness of the photographic image obtained is low, and if the amount is more than 60% by weight, the smoothness of the coated surface is lost, which is not preferable in terms of quality.

The base paper used to produce the support of the present invention is selected from the materials commonly used in photographic printing papers. Examples of such a material include natural pulp paper, synthetic pulp paper, mixed paper of natural pulp and synthetic pulp, and various laminated papers, and these base papers usually have a thickness of 30 to 500 microns. Used in

The photographic paper support of the present invention has a base paper coated with a synthetic resin,
It is manufactured by carrying out a curing treatment with an electron beam, and for example, the following method can be adopted.

On one side of the base paper, a resin composition containing a white pigment and curable by electron beam irradiation is applied in a layer amount of 5 to 50 g / m ² , followed by irradiation with an electron beam of 0.2 to 20 Mrad. Cure the film. After curing, the coated paper was wound up, and the back surface which was not coated in the second working step was exposed to a resin composition containing the same white pigment as used in the above step or electron beam irradiation containing no white pigment. Then, the curable resin composition is applied in a layer amount of ² to 50 g / m ² , and the electron beam is continuously applied to 0.2 to
Irradiation with 20 Mrad is carried out to cure the coating film and obtain a photographic printing paper support.

It is also possible to apply both sides of the base paper with the above resin composition and then irradiate it with an electron beam to cure it at once, or to contain a white pigment on only one side and cure it by electron beam irradiation. A photographic paper support coated with the composition and cured by electron beam can also be produced.

As a method of applying the resin composition to the photographic paper base paper, air doctor coat, blade coat, reverse call coat, gravure coat, cast coat, transfer roll coat, spray coat and the like can be used.

As an electron beam irradiation device for carrying out a curing treatment by electron beam irradiation, a skinning system or a curtain beam system can be adopted, but a curtain beam system which can obtain a large output at a relatively low cost is preferable. As electron beam characteristics, an acceleration voltage of 100 to 500 KV and an absorbed dose of 0.2 to 20 Mrad are preferable.

If necessary, after coating or curing, the surface may be smoothed by a mirror surface roll or the like or surface matted by a silk roll or the like.

Next, the present invention will be described in more detail with reference to Production Examples and Examples, but the present invention is not limited to the following Examples unless it exceeds the gist.

Production Example 1 Urethane resin containing carbon-carbon double bond (hereinafter referred to as EB
C) (abbreviation as urethane resin) -1 Production of a thermometer, a stirrer, a dropping funnel, and a four-necked flask with an internal capacity of 2 equipped with a cooling tube with a drying tube were charged with 444 g of isophorone diisocyanate and 0.32 g of dibutyltin dilaurate and stirred. While maintaining the internal temperature at 80 ° C. Polytetramethylene ether glycol (PTMG1000)
A mixed solution of 500 g of Mitsubishi Kasei Kogyo Co., Ltd. (molecular weight 1000) and 425 g of polycaprolactone polyol (Placcel 208) (Daicel Chemical Industry Co., Ltd .: glycol of 850 molecular weight) was dropped from a dropping funnel. 2 at 80 ℃ after completion of dropping
A prepolymer having an isocyanate group at its end was prepared by heating for a period of time. Subsequently, 244 g of 2-hydroxyethyl acrylate and 0.64 g of hydroquinone monomethyl ether were added dropwise to this reaction product. 80 ℃ after dropping
After heating for 4 hours, EBC urethane resin-1 was obtained. The end of the reaction is 2250 cm in the infrared absorption spectrum.
^This was confirmed by the disappearance of absorption of the isocyanate group of ^-1 .

Production Example 2 Production of EBC Urethane Resin-2 The same apparatus as in Production Example 1 was charged with 129 g of 4,4′-methylenebis (cyclohexyl isocyanate), 0.07 g of dibutyltin dilaurate and 122 g of tetrahydrofurfuryl acrylate and the internal temperature was kept at 60 ° C. It was 2 to this
58 g of human loxyethyl acrylate were added dropwise. After completion of the dropping, heating reaction was performed at 70 ° C. for 3 hours. Subsequently, polycaprolactone polyol (Plaxel 30
5) 55 g of (triol having a molecular weight of 550) and polycaprolactone polyol (Plaxel 212) (molecular weight of 12)
A mixed solution of 125 g of 50 glycol) was charged, and the mixture was heated at 70 ° C. for 5 hours to obtain EBC urethane resin-2.

Production Example 3 Production of EBC Urethane Resin-3 The same equipment as in Production Example 1 was charged with 336 g of hexamethylene diisocyanate and 0.34 g of dibutyltin dilaurate and the internal temperature was kept at 80 ° C. 1100 g of polycaprolactone glycol having a molecular weight of 1100 with polytetramethylene ether glycol having a molecular weight of 850 as an initiator
Was dripped. After completion of the dropwise addition, a heating reaction was carried out at 80 ° C. for 2 hours to produce a prepolymer having an isocyanate group at the terminal. Subsequently, 244 g of 2-hydroxyethyl acrylate was added dropwise thereto. After the dropping was completed, the reaction was carried out at 80 ° C. for 5 hours to obtain EBC urethane resin-3.

Production Example 4 Production of EBC Urethane Resin-4 Isophorone diisocyanate 1 was placed in the same apparatus as in Production Example 1.
11 g, dibutyltin dilaurate 0.06 g and ethylene glycol diacrylate 105 g were charged, and the internal temperature was kept at 60 ° C. while stirring. To this, 85 g of polycaprolactone polyol (Plaxel 308) (triol having a molecular weight of 850) and polyether polyol (BPX-
33) (Asahi Denka Kogyo bisphenol A propylene oxide-added polyether) (58 g) and hydroquinone monomethyl ether (0.12 g) were added dropwise. After completion of the dropwise addition, a heating reaction was carried out at 70 ° C. for 4 hours to prepare a prepolymer having an isocyanate group at the terminal. 2 to this mixture
61 g of hydroxyethyl acrylate were added dropwise. After completion of the dropping, heating reaction was carried out at 70 ° C. for 5 hours to obtain EBC urethane resin-4.

Production Example 5 Production of EBC Urethane Resin-5 Isophorone diisocyanate 4 was added to the same apparatus as in Production Example 1.
Charge 4.4 g, ethylene glycol diacrylate 62.6 g and dibutyl tin dilaurate 0.09 g, and set the internal temperature to 60.
℃. To this, polycaprolactone polyol (Plaxel 212) (glycol having a molecular weight of 1250) 125
g was added dropwise. After completion of the dropwise addition, a heating reaction was carried out at 70 ° C. for 3 hours to prepare a prepolymer having an isocyanate group at the end.
Subsequently, 18.4 g of glycerin was charged into this and the reaction was carried out at 70 ° C. for 3 hours to obtain a polyurethane prepolymer (a) having a hydroxyl group at the terminal.

Then add isophorone diisocyanate 6 to another similar container.
6.6 g, ethylene glycol diacrylate 34.8 g, dibutyltin dilaurate 0.05 g and hydroquinone monomethyl ether 0.15 g were charged, and the internal temperature was adjusted to 60 ° C. and the mixture was stirred.

2-hydroxyethyl acrylate 34.8g was dripped at this. After completion of the dropwise addition, a heating reaction was carried out at 70 ° C. for 2 hours to obtain a modified isocyanate (b) containing an isocyanate group and an acrylic group.

Next, the polyurethane prepolymer (a) and the modified isocyanate (b) were mixed and heated at 70 ° C. for 3 hours to obtain an EBC urethane resin-5.

Comparative Production Example 1 Production of EBC Urethane Resin-6 A device similar to that of Production Example 1 was charged with 696 g of a mixture of 80% 2,4-tolylene diisocyanate and 20% 2,6-tolylene diisocyanate and 464 g of diethylene glycol diacrylate. The internal temperature was kept at 60 ° C. 208 g of neopentyl glycol was added dropwise to this. 70 after dropping
A heating reaction was carried out at 0 ° C. for 2 hours. Subsequently, 487 g of 2-hydroxyethyl acrylate was added dropwise thereto. After completion of the dropping, heating reaction was carried out at 70 ° C. for 3 hours to obtain EBC urethane resin-6.

Comparative Production Example 2 Production of EBC Urethane Resin-7 Device similar to Production Example 1 Isophorone diisocyanate 44
4 g and 563 g of ethylene glycol diacrylate were charged and the internal temperature was kept at 60 ° C. while stirring. Polypropylene glycol (P-1000) (made by Asahi Denka Kogyo)
A mixed solution of 1000 g (glycol having a molecular weight of 1000) and 0.34 g of dibutyltin dilaurate was added dropwise. After completion of dropping, heating reaction was carried out at 70 ° C. for 4 hours. Subsequently, 244 g of 2-hydroxyethyl acrylate was added dropwise thereto. After completion of dropping, heat reaction at 70 ° C for 5 hours to perform EBC
Urethane resin-7 was obtained.

Example 1 The following composition was kneaded with a sand grind mill for 5 hours, and then filtered to obtain a resin composition colored by a white pigment and curable by electron beam irradiation.

EBC Urethane Resin-1 40 parts by weight Tetrahydrofurfuryl acrylate 10 〃 Ethylene glycol diacrylate 10 〃 Titanium dioxide (rutile type, surface treatment) 40 〃 n-Butyl acetate 10 〃 Base paper for photographic paper (weight about 160 g / m ^It was coated on one surface of ² ) so that the dry film thickness was 15 μm and dried.
Then, electron beam irradiation was performed by a 175 KV linear-filament type electron beam irradiation device so that the absorbed dose was 3 Mrad. Thus, a photographic printing paper support was obtained. The evaluation test results and the light resistance test results of the obtained support are shown in Table 1 and Table 2, respectively.

Example 2 EBC urethane resin-2 40 parts by weight Vinylpyrrolidone 10 〃 Tetraethylene glycol diacrylate 10 〃 Titanium dioxide (rutile type, surface treatment) 40 〃 n-butyl acetate 10 〃 The above resin composition is the same as in Example 1. To obtain a coating composition, which was applied to a photographic paper base paper and cured to obtain a photographic paper support.

Examples 3-5 and Comparative Examples 1-2 The EBC urethane resins-3 and -4 produced in Production Examples 3-5 and Comparative Production Examples 1-2 in place of the EBC urethane resin-1 in Example 1 were used. , -5, -6 and -7 were used respectively, and a resin composition having the same composition was prepared as in Example 1.
A coating composition was prepared by treating in the same manner as in 1., coated on a base paper for photographic paper, and cured to prepare a photographic paper support for photography.

In addition, rutile type titanium dioxide was used in all except that anatase type titanium dioxide was used in Example 3.

Evaluation Test Results Table 1 shows the results of evaluation tests conducted on the photographic paper supports obtained in Examples 1-5 and Comparative Examples 1-2.

Results of light resistance test Table 2 shows the results of a light resistance test performed on the printing paper supports obtained in Examples 1 to 5 and Comparative Examples 1 and 2.

The coating was applied so that the dry film thickness was 15 μm, and the photographic paper support cured by electron beam was exposed to sunlight for a predetermined number of days for evaluation.

Color difference (△ E): Measured with a colorimetric color difference meter from Nippon Denshoku Industries Co., Ltd. Gloss retention rate: Measured with a digital variable angle gloss meter (Suga Tester)

Continuation of the front page (56) Reference JP-A-57-27257 (JP, A) JP-A-53-57023 (JP, A) JP-A-54-56422 (JP, A) JP-A-54-151607 (JP , A) Actual development Sho 54-156808 (JP, U) Special public Sho 56-5987 (JP, B2) Special public Sho 53-40612 (JP, B2) Special public Sho 58-34488 (JP, B2) Special public Sho 60-30830 (JP, B2) US Patent 4092173 (US, A) US Patent 4171979 (US, A)

Claims (1)

[Claims] 1. A paper consisting of paper coated on both sides with a synthetic resin, at least one coating layer of which contains 15% by weight or more of a white pigment, and the binder of the synthetic resin coating layer comprises:
In a water-resistant photographic printing paper support containing a urethane resin (I) containing a carbon-carbon double bond, which is polymerized and cured by electron beam irradiation, the urethane resin (I) is
A water-resistant photographic printing paper support, which is a reaction product of (A), (B) and (C). (A) Polyisocyanate containing aliphatic polyisocyanate and / or alicyclic polyisocyanate as a main component (B) Polytetramethylene ether glycol and / or polyol containing polycaprolactone polyol (C) Active hydrogen and carbon -Monomers containing carbon double bonds