JPS59177543A - Production of base for photography - Google Patents

Abstract

PURPOSE:To improve the smoothness of a molded surface by irradiating primarily an electron ray to the coating layer of a base material then bringing the surface of the coating layer into contact with a forming material and stripping the same and irradiating secondarily the electron ray to the coating layer so that the surface of the coating material stripped from the forming material has the shape conforming to the surface shape of the forming material. CONSTITUTION:The coating layer which is disposed on a substrate and can be cured when irradiated with an electron ray is subjected to primary irradiation of the electron ray then the surface of the coating layer is brought into contact with a forming member such as a roll having the surface finished to a specular surface and is thereby stripped. The coating layer is thereafter subjected to secondary irradiation. The coating layer is stripped from the forming member. The above-mentioned primary irradiation is accomplished in such a way that the surface of the coating layer has the shape conforming substantially to the surface shape of the forming member when said layer is stripped from the coating layer. The quantity for the primary irradiation is adjusted by changing the intensity of the irradiation or the distance of the irradiation. A compd. having unsatd. double bonds or the compsn. contg. such compd. is used as the coating layer that can be cured by the irradiation of the electron ray.

Description

BACKGROUND OF THE INVENTION TECHNICAL FIELD The present invention relates in particular to a method of manufacturing photographic supports using electron beam irradiation.

Prior art and its problems Conventionally, a support having a polyolefin resin coating layer used as a support for photographic paper is formed by forming a coating layer on the surface of the paper base from a rubber in a molten state at about 300"C. As a result, the surface of the paper base material is deformed, resulting in poor surface properties and a drawback that it is difficult to form a mirror surface.

Furthermore, when applying a thin layer of polyolefin resin, it is necessary to apply the coating at a higher temperature, and the polyolefin tends to thermally decompose, causing yellowing and pinholes. Furthermore, it is preferable that the coating layer contains a white pigment, but when dispersing the white pigment in the molten polyolefin resin, the dispersibility is low and
You can increase the amount, but the sharpness of the photo image is not 1.
・It becomes a minute.

In order to overcome these drawbacks, a method has been proposed in which a coating layer that can be cured by electron beam irradiation is applied to a paper substrate and then cured by irradiating it with electron beams1 (Japanese Patent Application Laid-open No. No. 57-27257, No. 57-30830, No. 57
-49946).

According to this method, since the coating and curing are performed at room temperature, the surface of the paper base will not be rough or pinholes will occur, and since the white pigment is dispersed at room temperature,
It has good dispersibility, can increase pigment content, and improves sharpness.

However, with such electron beam irradiation alone, the smoothness of the coating layer is poor, and the desired pattern cannot be formed on the surface of the coating layer.

Therefore, in the above-mentioned Japanese Patent Application Laid-Open No. 57-30830, the coating layer is pressed against a high-gloss roll under mild pressure, and an electron beam is irradiated from the back side of the paper support while it is in contact with the forming surface of the roll. A method of curing and then peeling from the molding surface is disclosed.

However, in this method, since the electron beam is irradiated during contact with the molded member, a coating remains on the surface of the molded member upon peeling, resulting in poor quality and poor productivity.

Particularly when performing uneven molding, the coating adheres to the molding surface in an extremely large amount, making it difficult to put it into practical use.

Further, materials that can be cured by electron beam irradiation are usually anaerobic, and electron beam irradiation is performed in an inert slag or the like. Therefore, according to this method, it is necessary to incorporate rolls into the irradiation zone, which increases the size of the equipment, reduces the efficiency of oxygen removal in the zone, and increases the amount of inert gas, making it economically uneconomical. This may result in poor hardness and insufficient curing.

In the field of printing, a method is also known in which electron beams are irradiated while the molded member is in contact with the surface of the coating layer to give it a mirror finish or make it uneven (Japanese Patent Laid-Open No. 16481'6, 1983,
No. 57-2196.65), No. 57-22204, No. 57-59667), but these also have exactly the same drawbacks as above.

II. Purpose of the Invention The present invention was made in view of the above circumstances, and
The main purpose is to create a photographic support that has no yellowing, pinholes, etc., extremely high molding surface precision, and has a coating layer with a high-quality smooth surface or a molded surface. It is an object of the present invention to provide a method for manufacturing a photographic support which allows the molding surface to be changed, does not allow the coating to reach the molded member, does not increase the size of the apparatus, and has extremely high productivity.

Such objects are achieved by the present invention as described below.

That is, in the present invention, a coating layer that can be cured by electron beam irradiation and is formed on a base material is first irradiated with an electron beam, and then the surface of the coating layer is brought into contact with a molded member and peeled off. , the coating layer is subjected to secondary irradiation with an electron beam, so that when the coating layer is peeled off from the molded article, the surface of the coating layer can maintain a shape that substantially corresponds to the surface shape of the molded article; This is a method for producing a photographic support characterized by performing primary irradiation.

■Specific structure of the invention Hereinafter, a specific configuration of the present invention will be explained in detail.

The primary irradiation with the electron beam in the present invention is carried out so that after the coated surface after the primary irradiation is molded and peeled off from the molded member, the molding is substantially maintained.

The primary irradiation amount can be adjusted as appropriate by changing the irradiation intensity, changing the irradiation distance, irradiating through other obstructions, or controlling the amount of oxygen.

The irradiation amount varies depending on the method used, the type and thickness of the cured product, the type and content of the pigment, etc., so it is not possible to express the irradiation amount unambiguously, but it is usually 0.
, 01 Mrad to '10 Mrad is suitable.

Such primary irradiation is preferably performed in an inert gas atmosphere or in vacuum. As the inert gas, nitrogen gas, carbon dioxide gas, argon gas, helium gas, etc. can be used.

The secondary irradiation dose of the electron beam is applied to the molded coating layer in an inert gas atmosphere or in a vacuum until curing is completed.

By this irradiation, the reaction of unreacted radicals remaining in the coating layer after the primary irradiation can be completed.

Note that, if necessary, after the secondary irradiation, tertiary and fourth irradiation can be performed with an electron beam, or heating with hot air or far infrared rays can be performed.

Note that the secondary irradiation dose is usually 0.5 Mrad to 15
It is about Mrad.

Moreover, the primary irradiation and the secondary irradiation may be performed on the base material.

The molded member in the present invention is a material whose surface has been subjected to molding processing, such as a roll with a mirror-finished surface as a means of increasing the smoothness of the coating layer, or a roll with minute irregularities on the surface as a means of forming a desired pattern on the coating layer. The formed rolls etc...
be.

Types of molding include mesh, rough surface, fine-grained surface, etc., and various types of molding can be applied as necessary.

Such a roll is produced by a known method.

Moreover, instead of a roll, an endless belt or the like may be used.

Note that there is no limit to the pressure at which the molded member and the coating layer come into contact.

The coating layer curable by electron beam irradiation used in the present invention may be a compound having an unsaturated double bond or a composition containing the same, and such a compound preferably has two unsaturated double bonds. It is a prepolymer and/or oligomer having two or more of these, and can further contain a monomer (vinyl monomer) having an unsaturated double bond for the purpose of adjusting viscosity.

Further, a preferred embodiment of the composition includes an embodiment containing an inorganic white pigment.

Prepolymers or oligomers having two or more unsaturated double bonds include those described in JP-A-57-30830, or any of the known prepolymers and oligomers disclosed in the related technical field. But that's fine.

In addition, epoxy group (-C)l-C)l-) at the terminal, \
1 or vinyl ether group (-CH2=C)I -0
-) can also be suitably used.

Specific examples of such prepolymers and oligomers include the following.

1) Unsaturated polyester Special Publication No. 48-23654, Special Publication No. 49-23293, Special Publication No. 47103-1973, Special Publication No. 49-44572
Compounds disclosed in Japanese Patent Publication No. 54-7473 2) Modified unsaturated polyesters Urethane modified unsaturated polyesters, especially compounds disclosed in Japanese Patent Publication No. 48-14667 Acrylic urethane modified unsaturated polyesters, especially Liquid unsaturated polyester 4,'r having an acrylic group at the end of the compound disclosed in No. 48-14.790, U.S. Pat. No. 3,455,802 and U.S. Pat.
Compound 3) Acrylic polymer polynyester acrylate A, C, J, Van Oo, st, erhout an, disclosed in No. 85732
d A, van Ne-erbos, Doub'l
e Liaison-C:hiIIIPeint,
! 27 (295), 135 (1f180) Polyester acrylate oligomer epoxy acrylate Compounds disclosed in Japanese Patent Publication No. 47-13023 and Japanese Patent Publication No. 57-162713, that is, polyfunctional epoxy compounds, acrylic Acid, other α, β
Epoxy acrylate silicone acrylate obtained by adding unsaturated carboxylic acid A condensate of a hydroxyl or methoxy group-containing silicone and hydroxyethyl methacrylate as disclosed in Japanese Patent Publication No. 48-22172 and Japanese Patent Application Laid-open No. 48-39594.

Urethane acrylate US Pat. No. 3,864,133, US Pat. No. 389,1523, US Pat.
No. 172, JP-A-48-39594, JP-A-49-2
No. 6337, Japanese Patent Publication No. 49-35346, Japanese Patent Publication No. 49-9604
No. 3, Special Publication No. 52-31239, Japanese Patent Publication No. 54-803
No. 94, JP-A-5.4-129034, JP-A-54-
Specifically, the urethane acrylate disclosed in No. 127994 is a urethane acrylate obtained by adding hydroxyethyl methacrylate to a polyfunctional incyanate compound.

A urethane acrylate obtained by reacting a polyoxyalkylene bisphenol AI conductor with a polyisocyanate and a hydroxyl group-containing acrylate.

Examples include amide urethane acrylate, which is obtained by reacting an amide-containing compound having a hydroxyl functional group, a polyisocyanate, and a hydroxy-containing acrylate compound.

4) Butadiene-based polymer urethanized 1,2-polybutadiene disclosed in JP-A-50-12:3187 and JP-A-54-148
Examples include modified polybutadiene, which is disclosed in No. 094, in which a monoester compound is added to the epoxidized polybutadiene, and an aliphatic lower carboxylic acid is further added thereto.

The following compounds may be used alone or in combination of two or more.

In addition, its number average molecular weight is about 500 to 20,000,
Preferably it is about 1000 to 1oooo.

In a preferred embodiment, the concentration of the inorganic white pigment blended with these prepolymers and oligomers is from 10/l to 1/1 in terms of the mixing weight ratio of these polymers and pigments.
Preferably, the ratio is about 5/1 to 0.7/l.

Moreover, the monomer having an unsaturated bond is preferably in a weight ratio of about 1/10 to 10/l with respect to these polymers.

A monomer having an unsaturated bond (vinyl monomer) is blended for the purpose of lowering the viscosity of the composition and improving coating workability, and this monomer improves the curing speed.

These monomers may be used alone, or two or more of these monomers may be used in combination, if necessary.

Representative examples of these monomers include the following.

a) Monofunctional monomers methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl methacrylate-1, 2
-Hydroxyethyl acrylate, 2-hydroquine ethyl methacrylate, glycidyl methacrylate, n
-hexyl acrylate, lauryl acrylate, etc. b) Bifunctional monomer 1.6-hexanethiol diacrylate 1., 1,6-
Hexanethiol dimethacrylate, neopentyl glycol, 1,4-butanediol diacrylate-1, ethylene glycol diacrylate, polyethylene glycol diacrylate, pentaerythryl diacrylate, divinylbenzene, etc.c) Trifunctional or higher functional compounds - Trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, pentaerythritol triacrylate, dipentaerythritol hexaacrylate, acrylic ester of ethylenediamine, etc. Inorganic pigments include JP-A-57-27257;
Those described in No. 57-30830, namely, TiO2 (anatase, rutile type), ZnO2, S
i02, Ba5O4C, aSO4, CacO3,'i
Milk 71. /-t etc. are preferred.

Other non-hardening binders can also be added as required.

For example, the one described in Japanese Patent Application Laid-Open No. 57-30830. That is, they include cellulose ester, polyvinyl butyral, polyvinyl acetate, vinyl acetate copolymer, styrene-acrylic acid copolymer, saturated or unsaturated styrene-unpolyester resin, and the like.

The substrate used in the present invention is usually paper, and can be made of natural pulp, synthetic pulp, or a mixture thereof.

For example, any paper with good flatness, such as photographic Kawahara paper or high-quality paper produced by a known method, may be used.

The thickness is preferably about 80 to 250 μm, and H94 is preferably about 80 to 200 g/m'.

These papers can be used with addition of paper strength enhancers, sizing agents, coloring agents, light-concentrating brighteners, etc., if necessary.

Other films include polyester, polystyrene, etc.
- Can be used as an alternative to paper distribution, with or without pigments.

As the electron beam accelerator for curing the coating layer of the present invention, a bump graph scanning method, a double scanning method, and a curtain beam method can be used. in this case,
Particularly preferred is the curtain beam method, which is relatively inexpensive and provides high output.

As for the electron beam characteristics, the acceleration voltage is 100 to 10
00 KV, preferably 150-300 KV.

This is because if the voltage is lower than 100KV, the amount of permeation is insufficient, and 1
This is because a value larger than 00 OKV is not economical.

Methods for coating the substrate with the coating layer of the present invention include blade coating, air knife coating, gravure coating, reverse roll coating, spray coating, curtain coating,
Transfer coat, etc., can be used.

The coating amount is preferably 3 to 80 gm, preferably 5 to 5'OILm.

If it is smaller than 3 μm, it will penetrate into the base material, resulting in poor smoothness and difficulty in forming a continuous film.
If it is larger than 0 gm, there will be many uneven coatings and a large amount of energy will be required for curing, which is economically disadvantageous and curing will be insufficient.

In addition, the dispersion method when the coating layer is made into a composition is as follows:
Various kneading machines may be used.

For example, two-roll mill, three-roll mill, ball mill, pebble mill, Nigu, Santo Kleingu,
These include high-speed impeller dispersion machines, high-speed stone mills, high-speed impact mills, and homogenizers.

In the present invention, the steps consisting of primary irradiation, contact and peeling with the molded member, and secondary irradiation may be performed sequentially or in stages for each base material, but usually from the viewpoint of productivity. ,
It is preferable to carry out these steps continuously while conveying the elongated base material having the coating layer. Examples of such cases are shown in FIGS. 1 to 4.

In the embodiment shown schematically in FIG. 1, a substrate (paper,
The plastic) 1 is first irradiated from the back side with an electron beam accelerator 4, and is molded by contacting with a molded member (mirror roll, mesh, rough surface, roll for fine grain surface molding, etc.) 3, and after peeling, it is irradiated again with electron beams. This is an example in which secondary irradiation is performed from the opposite side of the coated surface using a line accelerator 5, and then winding is performed.

The embodiment shown schematically in FIG. 2 is similar to the example shown in FIG. In this method, the coating layer 2 is patterned by performing the following operations.

The embodiments schematically illustrated in FIGS. 3 and 4 do not carry out the primary irradiation of the electron beam accelerator 4 from the opposite side of the coating formation surface in the examples shown in FIGS. 1 and 2, respectively, and
By increasing the irradiation amount from the position of the electron beam accelerator 5 for secondary irradiation and transmitting it through the base material 1 such as a paper support, the electron beam that has passed through the base material 1 is absorbed and the primary irradiation is performed. This is the way to do it.

■Specific Effects of the Invention According to the present invention, the accuracy of patterning and smoothing of the subsequent coating layer is extremely high and stable.

In addition, there are almost no yellowing or pinholes.

Furthermore, there is no adhesion of coatings to the molded parts.

In addition, since there is no need to arrange a molded member in the electron beam irradiation zone, the apparatus does not become larger.

An advantageous method of manufacturing a support which is very useful as a support for photographic paper is therefore achieved.

(2) Specific Examples and Comparative Examples of the Invention Hereinafter, specific examples and comparative examples of the present invention will be shown to explain the present invention in further detail.

Example 1 Urethane acrylate oligomer 30% by weight (urethane acrylate oligomer described in US Pat. No. 777,031) 1.6-hexafushiol dimethacrylate 20% by weight 2-ethylhexyl acrylate 10ii% hydroxyethyl methacrylate lo weight% titanium dioxide ( anatase type) 30% by weight of the above composition into a ball,
After dispersing in a mill for 16 hours, the mixture was coated on one side of photographic base paper with a N content of 180 g/rn' using a doctor coater to a coating thickness of about 30 gm.

This coating layer was coated from the opposite side of the paper base under a nitrogen gas atmosphere at an accelerating voltage of 0 and 5 Mr.
Primary irradiation with an electron beam was performed to obtain an absorbed dose of ad.

Next, the irradiated coating layer is stamped by pressing it onto a chrome roll whose surface has been patterned (approximately 20 gm in depth).The mold and coating are then peeled off from the roll, and the embossed coating layer is immediately exposed to nitrogen gas. In an atmosphere, the absorbed dose is 3 Mr.
Secondary irradiation was performed from the opposite side of the paper base material so that the paper base material was cured and then rolled up.

The same composition as above was coated on the opposite side which had been drawn, cut and stamped using a blade coater so that the coating thickness was approximately 30 pm, and the coating was coated under nitrogen gas using the electron beam accelerator 4 shown in Fig. 1. After curing by irradiation to give an absorbed dose of 4' Mrad, the film was wound up. This sample is sample No.
shall be.

Comparative Example 1 The same operation as above was performed except that the primary irradiation was not performed, and the sample prepared was designated as sample 2.

Comparative Example 2 The same liquid composition used in Example 1 was weighed at 180 g.
/ m' photo base paper with a coating thickness of approximately 40' on both sides.
It was coated with a doctor coater to give a gm of 9. While pressing this coating layer onto a roll with a high gloss surface and cooled from the inside using cooling water at the pressure described in JP-A-57-30830, from the opposite side. After curing it by electron beam irradiation at an absorbed dose of 3.-5 Mrad in a nitrogen gas atmosphere, it was peeled off from the roll and wound up.

This sample is designated as 3 between samples.

Example 2 Unsaturated polyester 35% by weight (Compound synthesized according to Synthesis Example 1 of JP-A-54-7473) Ethylene glycol diacrylate) 10% by weight Trimethylpropane 20ffiffi% Triacrylate Titanium dioxide (anatase type) 35% by weight Above After dispersing the composition for 24 hours in a Paul Mill, weighing 16
The coating thickness is approximately 40 g on both sides of 0 g/m' photographic base paper.
It was coated with a doctor coater so that the thickness of the film was 100 m. This coating layer was coated under a nitrogen gas atmosphere according to the example shown in FIG.
The electron beam was primarily irradiated from the opposite side of the paper base material so as to obtain the absorbed dose of Mrad.

Next, the surface of this coating layer was smoothed by pressing it against a mirror-finished chrome-plated roll, and then peeled off from the roll. Immediately thereafter, secondary irradiation with an electron beam was performed under a nitrogen gas from the opposite side that had come into contact with the mirror-finished roll to give an absorbed dose of 4 Mrad, and the film was cured and then wound up.

This sample is designated as 4 between samples.

Comparative Example 3 Weighed 160 g of the composition solution used in Example 2.
/m' photographic base paper with a coating thickness of approximately 40 gm on both sides.
Coat with a doctor coater so that
The surface is high gloss, and while it is pressed against a roll that has been cooled from the inside using cooling water, it is cured from the other side under a nitrogen gas atmosphere at an accelerating voltage with an absorbed dose of 5 Mrad, and then removed from the roll. It was peeled off and rolled up.

This sample is designated as 5 between samples.

Table 1 shows the results of observing the surface shapes of these samples.

Table 1 1 A high-gloss silky pattern is formed with good reproducibility.

2. Lots of uneven gloss and peeling.

3. Lots of uneven gloss and peeling.

4. High gloss and good smoothness.

5. Lots of uneven gloss and peeling.

As is clear from the results shown in Table 1, samples No. 1, No. 1, and No. 4 in which the coating layer was irradiated with an electron beam before molding.
However, it can be seen that the molding of extremely high quality has a surface.

[Brief explanation of drawings]

FIGS. 1 to 4 are diagrams for explaining embodiments of the present invention, respectively. 1 ... Base material. 2.2′... Covering layer. 3... Molded member. 4.5 ...... Electron beam accelerator applicant Roku Konishi Photo Industry Co., Ltd. Agent Patent attorney Yo Ishii - Figure 1 Figure 2 Figure 4

Claims (1)

[Claims] 1. A coating layer that can be cured by electron beam irradiation, which is formed on a base material, is subjected to primary irradiation with an electron beam, and then the surface of the coating layer is brought into contact with a molded member and peeled off, and then the coating layer is It consists of a step of performing secondary irradiation with an electron beam, and the primary irradiation is performed so that when the coating layer is peeled off from the molded part, the surface of the coating layer can maintain a shape that substantially corresponds to the surface shape of the molded part. A method for producing a photographic support, characterized in that: