JPH04153395A - Production of coated paper - Google Patents

Abstract

PURPOSE:To obtain coated paper having excellent bond strength by forming a specific coated layer on the surface of a carrier film, bonding paper to the coated layer under pressure and irradiating the bonded material with ionizing radiation while rewinding the material from a winding roll. CONSTITUTION:A coating agent comprising a solution of ionizing radiation curing resin (containing water) in an organic solvent is applied to the surface of a carrier film and dried to form a coated layer. Then paper is bonded to the face of the coated layer and the prepared bonded material consisting of the carrier film and the paper is wound on a winding roll. Then the bonded material is irradiated with ionizing radiation while rewinding the bonded material from the winding roll and further the carrier film is released and removed to give the objective coated paper.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for producing coated paper having a coating layer made of an ionizing radiation-curable resin, and the present invention relates to a method for producing coated paper having a coating layer made of an ionizing radiation-curable resin, and the present invention relates to a method for producing coated paper having a coating layer made of an ionizing radiation-curable resin. A coated paper having a coating layer made of an ionizing radiation-curable resin that faithfully reproduces the state of the coating layer on the surface of the coating layer, and which also has excellent adhesive strength between the paper surface and the coating layer. To provide a method that can be obtained easily and reliably.

[Prior Art] It is widely practiced to form a glossy resin layer on the surface of paper mainly for the purpose of protecting the printed surface or giving a decorative finish.For example, l) forming a resin layer with a nitrocellulose coating solution Methods of forming a coating layer on the paper surface 2) A method of pasting a transparent film on the paper surface with an adhesive, 3) A method of forming a coating layer on the paper surface using a coating agent made of synthetic resin, etc. is being used.

[Problems to be Solved by the Invention] By the way, in the conventional method for forming a resin coating layer described above, for example, the adhesive strength between the paper surface and the coating layer is insufficient, or the coating layer is It has drawbacks such as insufficient surface smoothness and, furthermore, the need for a long aging process after application of the coating agent, making it difficult to meet quick delivery deadlines.

For this reason, in recent years, a coated paper production method using a coating agent made of an ionizing radiation-curable resin has begun to be used as a method for producing coated paper in which the coating layer is instantly cured by irradiation with ultraviolet rays or electron beams.

This method of manufacturing coated paper using a coating agent made of ionizing radiation-curable resin instantly cures the coating layer by irradiation with ultraviolet rays or electron beams, so it is possible to meet quick delivery times. , there is no opportunity to bleed out the air trapped between the coating agent and the paper, or to improve the wetting between the coating agent and the paper, resulting in poor appearance and poor paper quality due to insufficient air bleed. Poor adhesive strength between the coating layer and the paper occurs due to insufficient wetting of the coating agent.

In contrast, the method of the present invention is a method for producing coated paper in which a coating layer is formed using a coating agent made of an ionizing radiation-curable resin. In addition, there is no problem with trapped air between the coating layer and the paper, and furthermore, the coated paper does not cause insufficient wetting between the coating agent and the paper. A manufacturing method is provided.

[Means for Solving the Problems] The method for producing coated paper according to the invention of Section 1 includes coating the surface of a carrier film with a coating agent consisting of an organic solvent solution or a water-organic solvent solution of an ionizing radiation curable resin, a step of forming a coating layer by drying; a step of press-bonding paper to the surface of the coating layer; and a step of winding up the obtained press-bonded body of the carrier film and paper onto a winding roll;
irradiating the crimped body with ionizing radiation while unwinding the crimped body from a take-up roll; and peeling off the carrier film from the crimped body that has been subjected to the ionizing radiation irradiation treatment.
and obtaining coated paper by removing the coated paper.

The method for producing coated paper according to the invention of Section 2 is based on the method for producing coated paper according to the first invention, in which ionizing radiation is present in a coating agent consisting of an organic solvent solution or a water-organic solvent solution of an ionizing radiation-curable resin. The curable resin is made of a polyether polyurethane resin or a polyester polyurethane resin having an acroyl group or a metaacroyl group.

Further, the method for producing coated paper according to the invention in Box 3 is the method for producing coated paper according to the invention in Box 1 or the second invention, in which an organic solvent solution or a water-organic solvent solution of an ionizing radiation curable resin is used. A coating agent consisting of acetophenones such as jetoxyacetophenone, benzoin alkyl ethers such as benzoin isobutyl ether, benzyl ketals such as benzyl dimethyl ketal, or ketones such as pentuphenone and 2-chlorothioxanthone. It contains a photopolymerization initiator selected from the following, and uses ultraviolet irradiation treatment from the surface of the carrier film as the ionizing radiation irradiation step.

Furthermore, the method for manufacturing coated paper according to the invention in Book Box 4 is described in Book No. 1 above. Second. Alternatively, in the method for producing coated paper according to the third invention, the carrier film to which the coating agent is applied is a biaxially stretched polypropylene film.

It consists of a biaxially stretched polyester film or a biaxially stretched polyamide film.

The method for manufacturing coated paper according to the invention in Book Box 5 includes, as the carrier film to which the coating agent is applied, in the method for manufacturing coated paper according to Book Box 3 or the fourth invention.
A film having a transmittance of ultraviolet rays of 250 to 400 nm of 20% or more is used.

In the method for producing coated paper of the present invention having the above structure, the coating agent applied to the carrier film is:
It consists of an organic solvent solution or water-organic solvent solution of an ionizing radiation-curable resin that is cured by irradiation with ultraviolet rays or electron beams, and the ionizing radiation-curable resin has a (meth)acrylic double bond. One or two oligomers
Oligomers having a molecular weight of 300 to 6,000, preferably 1,000 to 3,000 are used as a mixture of more than one species, such as epoxy (meth)acrylate, polyurethane (meth)acrylate, polyolefin glycol (meth)acrylate, and polyester (meth)acrylate. Ru.

The epoxy (meth)acrylate includes a reaction product of an epoxy resin having a glycidyl group at the end and (meth)acrylic acid, such as bisphenol-A type epoxy acrylate, and polyurethane (meth)acrylate.
Acrylate is a reaction product of a polyurethane resin having an incyaneto group at the end and a compound having a vinyl group and a hydroxyl group in the molecule, such as 2-hydroxyethyl (meth)acrylate, and a polyolefin glycol (meth)acrylate. ) Acrylates include, for example, di(meth)acrylic acid ester of polyethylene glycol, etc.
Further, as the polyester (meth)acrylate, a reaction product obtained by treating a polyester of phthalic anhydride and diethylene glycol with (meth)acrylic acid is used.

Of course, the above-mentioned (meth)acrylic-modified oligomers may be a mixture thereof.

Further, the solvent in the coating agent includes, for example,
Single organic solvents such as ethyl acetate, toluene, methyl ethyl ketone, isopropyl alcohol, ethyl alcohol, methyl alcohol, butyl alcohol, mixed solvents, and mixed solvents of the above organic solvents and water are used.
In the case of a mixed solvent of water and organic solvent, the mixed solvent of water and organic solvent is used in an amount of about 10 to 1000 parts by weight of water per 100 parts by weight of the organic filter.

The coating agent is usually a solution containing 100 parts by weight of an ionizing radiation curable resin and about 50 to 1000 parts by weight of a solvent. Further, when curing treatment with ultraviolet rays is performed, 02 to 10 parts by weight of a photopolymerization initiator, such as benzoin alkyl ether, benzophenone, benzoin, etc., is further added thereto.

In addition, for the photopolymerization initiator, a photosensitizer such as dimethylaminoethanol, triphenylphosphine, N,N-dimethylaniline, dimethylaminobenzoic acid ester, etc. may be used in combination, if necessary. Of course.

As a photopolymerization initiator, for example, when a thiogysanthone compound such as 24-diethyl dioxanthone or a hydrogen abstracting compound such as a benzophenone compound such as 33-dimethyl-4-methoxy-benzophenone is used, For example, when using a self-cleavable photoinitiator such as 1-hydroxycyclohexyl phenyl ketone or benzyl dimethyl ketal, the decomposition products of the photopolymerization initiator generated by irradiation with ultraviolet rays, i.e., cyclohexanone, benzaldehyde, benzoin, etc. Since there is no generation of acid methyl, etc., the generation of odor due to the decomposition products is suppressed, and the problem of generation of off-flavors is solved.

The coating agent consisting of an organic solvent solution or a water-organic solvent solution of the ionizing radiation curable resin is usually coated onto the carrier film surface by a coating method such as gravure coating, direct coating, reverse roll coating, etc. Applicable to about .5 to 30g (solid component)/m2.

For the carrier film in the method for producing coated paper of the present invention, for example, a single layer film or a laminated film made of a biaxially oriented polypropylene film, a biaxially oriented polyester film, a biaxially oriented polyamide film, etc. is used, and the coating in the carrier film is used. When the coated surface of the coating agent has a mirror surface, a coated paper with a glossy surface of the coating layer can be obtained, and the surface coated with the coating agent of the carrier film has a finely uneven surface, for example, by sandblasting, etc. In this case, a coated paper exhibiting a matte state is obtained.

In addition, when the resin component in the coating agent applied to the carrier film is cured by irradiation with ultraviolet rays in a subsequent step, the irradiation with ultraviolet rays must be performed from the surface of the carrier film. In this case, the ultraviolet transmittance between 250 and 400 nm is 2.
Preferably, 0% or more carrier film is utilized.

The method for producing coated paper of the present invention includes applying the above-mentioned coating agent to the surface of the carrier film, and further removing the solvent in the coating agent on the carrier film.
For example, by blowing hot air, etc., the material is evaporated and removed, and paper is brought into close contact with the surface of the resulting coating layer to form a pressed body of the carrier film/uncured coating layer/paper. After this is continuously wound up with a winding spout, the crimped body is irradiated with ionizing radiation while being rewound from the winding roll to cure the coating layer.

In addition, in the step of curing the coating layer, it goes without saying that ionizing radiation of a type corresponding to the composition of the coating agent used in forming the coating layer is irradiated.

When irradiating with ultraviolet ionizing radiation, a high-pressure mercury lamp, a metal halide lamp, or the like is usually used.

In this ultraviolet irradiation process, if the ultraviolet ray irradiation rate is too fast, the irradiation dose will be insufficient, resulting in insufficient curing of the coating layer, and if the irradiation rate is too slow, the The heat and ultraviolet rays from the lamp cause the carrier film to curl as the film shrinks, so for boat fishing, the output of the ultraviolet lamp is 80 to 120 w/cm, and the irradiation speed is 20 to 150.
It is preferable to irradiate the ultraviolet rays at a rate of approximately m/min.

In addition, when irradiating ionizing radiation with an electron beam, if the energy dose is too large, the carrier film in the crimped body will deteriorate and the surface of the coating layer on the resulting coated paper will not be homogeneous. It is better to carry out at the irradiation dose.

[Example] Hereinafter, the specific structure of the method for producing coated paper of the present invention will be explained with reference to Examples.

Example 1 A coating agent having the following composition was applied to the mirror surface side of a carrier film made of a biaxially stretched polypropylene film having a mirror surface state and a thickness of 20 μm using a gravure roll coating method to form a 5 gf solid acid at a rate of 7 m2. 80% on the coated surface of the coating agent.
By blowing hot air at .degree. C. for 2 seconds, ethyl acetate, the solvent in the coating agent, was evaporated and dried to form a coating layer of an ultraviolet curable resin.

Coating 1 and ultraviolet curable resin [polyether-based polyurethane diacrylate average molecular weight: 3000 prepared by treating a reaction product of polyethylene glycol and tolylene diisocyanate with hydroxyethyl acrylate] ...40 parts by weight Photoinitiator [benzoin isopropyl ether] ...1 part by weight Photosensitizer [p-dimethylaminobenzoic acid ethyl ester] ...1 part by weight Ethyl acetate: 60 parts by weight Next, a paperboard with a basis weight of 400 g/m2 was brought into close contact with the surface of the coating layer of the ultraviolet curable resin coating agent, and the paperboard was further pressed with nip rolls to obtain a crimped body. was continuously wound up with a winding roll.

Immediately after the winding process of the 2000 m long crimped body is completed using the above-mentioned winding roll, the crimped body is unwound from the winding roll and a high-pressure mercury lamp [
80w/cm, lamp length: 90cm, Nippon Battery Co., Ltd.
] by the distance to the carrier film: I.

chi, irradiation speed (line speed during irradiation): 100m/
The surface of the carrier film was irradiated with ultraviolet rays at a temperature of 1.5 min to obtain a laminated sheet of the carrier film and paperboard.

Subsequently, when the carrier film was peeled off and removed from the obtained laminated sheet, the carrier film was removed smoothly and a coated paper having a coating layer with extremely high gloss was obtained.

Moreover, the adhesive strength between the coating layer and the paperboard in the obtained coated paper was also good.

Example 2 A coating agent having the following composition was applied to the mirror surface side of a carrier film made of a biaxially stretched polypropylene film having a mirror surface state and a thickness of 20 μm using a gravure roll coating method in an amount of 5 g (solid component) in an amount of 7 m2. and then heated to 80°C on the coated surface of the coating agent.
By blowing hot air for 2 seconds, ethyl acetate, the solvent in the coating agent, was evaporated and dried to form a coating layer of electron beam curable resin.

Composition of coating agent Electron beam curable resin [Polyether-based polyurethane diacrylate prepared by treating the reaction product of polyethylene glycol and tolylene diisocyanate with hydroxyethyl acrylate Average molecular weight: 3001...40 weight 60 parts by weight of ethyl acetate Next, a paperboard having a basis weight of 400 g/m2 was brought into close contact with the coating layer surface of the coating agent made of the electron beam curable resin, and was further crimped with nip rolls to obtain a crimped body. was continuously wound up with a winding roll.

After completing the winding process of the 2000 m long crimped body using the aforementioned winding roll, while unwinding the crimped body from the winding roll, an electron beam irradiation device [20
0 KV, pilot machine, upstream manufactured by ESI Co., Ltd., distance to carrier film +10 cm, irradiation speed (line speed during irradiation): 100 m/min, irradiation treatment with electron beam at irradiation dose of 2 Mrad was performed on the carrier film surface. A laminated sheet of carrier film and paperboard was obtained.

Subsequently, when the carrier film was peeled off and removed from the obtained laminated sheet, the carrier film was removed smoothly and a coated paper having a coating layer with extremely high gloss was obtained.

Moreover, the adhesive strength between the coating layer and the paperboard in the obtained coated paper was also good.

Example 3 All the configurations were the same as the corresponding configurations of Example 1 except for using a carrier film made of polyethylene terephthalate film having a thickness of 25 Lt.
Coated paper, which is the target product of the method of the present invention, was obtained.

The removal of the carrier film from the laminated sheet was smooth as in Example 1, and a coated paper with extremely good gloss on the surface of the coated layer was obtained.

Furthermore, the adhesive strength between the coating layer and the paperboard in the obtained coated paper was also good.

Comparative Example 1 A coating agent having the same composition as the coating agent used in Example 1 was applied directly to paperboard with a basis weight of 400 g/m2.
By gravure roll coating method, 5g [solid component]7
Then, by blowing hot air at 80 ° C. for 2 seconds on the coated surface of the coating agent, ethyl acetate, which is the solvent in the coating agent, is evaporated and dried, and then, The coated paper used in Example 1 was subjected to ultraviolet irradiation treatment under the same conditions from the surface of the coating layer to obtain a coated paper for comparison.

The surface smoothness of the coating layer in the obtained coated paper was not sufficient, and therefore the gloss was insufficient, and furthermore,
The adhesive strength between the coating layer and the paperboard was also not sufficient.

Comparative Example 2 In the manufacturing process of the coated paper of Example 1, a crimped body of carrier film/coating layer/paperboard was obtained by applying pressure and crimping with nip rolls, and then the obtained crimped body was rolled up and rolled. Without winding it up, it was immediately subjected to ultraviolet irradiation under the same conditions as those used in Example 1, and then the carrier film was peeled off from the obtained laminated sheet.

By removing it, a coated paper was obtained for comparison.

The resulting coated paper had insufficient gloss and smoothness on the surface of the coating layer due to air entrapment between the carrier film and the coating agent.

[Operations and Effects of the Invention] The method for producing coated paper of the present invention comprises applying a coating agent consisting of an organic solvent solution or a water-organic solvent solution containing an ionizing radiation curable resin to a carrier film and drying the coated paper. A coating layer is formed, and then paper is crimped onto the surface of the coating layer, the resulting crimped body of the carrier film and paper is wound up on a take-up roll, and then the crimped body is rolled up from the take-up roll. The desired coated paper is obtained by irradiating the pressed body with ionizing radiation while returning it, and then peeling off and removing the carrier film.

Therefore, in the method for producing coated paper of the present invention, a coating agent made of an organic solvent solution is used, and prior to the curing process of the coating layer, the carrier film having the coating layer and the surface of the coating layer are coated. The coating layer is cured by irradiating the crimped body with ionizing radiation while unwinding the crimped body with the paper that is in contact with the paper, and then winding it up with a take-up roll. Before curing the layer,
The air trapped between the paper and the coating layer is sufficiently removed, and at the same time, the wetting between the coating agent and the carrier film is complete.

This eliminates the occurrence of roughness on the surface of the coating layer due to the presence of trapped air between the carrier film and the coating layer, or insufficient wetting of the coating agent to the carrier film. A coated paper is obtained which has a coating layer of good quality in which the state of the surface of the carrier film to which the coating agent is applied is faithfully transferred to the surface.

In addition, the method for producing coated paper of the present invention includes, for example, an aging process when forming a coating layer using a coating agent made of a two-component curable resin, or a process in which a transparent film is attached to the paper surface. Since there is no need to go through the process of drying or aging the adhesive, the manufacturing process can be extremely shortened and delivery can be completed within a short period of time.

Furthermore, since the method of the present invention utilizes a coating agent made of an organic solvent solution, it is easy to adjust the viscosity of the coating agent, and it exhibits an excellent effect on operability.

Patent applicant: Dai Nippon Printing Co., Ltd. Agent Kiyoko Arata

Claims (1)

[Claims] 1. A coating layer is formed by applying and drying a coating agent consisting of an organic solvent solution or a water-organic solvent solution of an ionizing radiation curable resin on the surface of the carrier film, and then Paper is crimped onto the surface of the coating layer, the resulting crimped body of the carrier film and paper is wound up on a take-up roll, and then, while the crimped body is unwound from the take-up roll, ionizing radiation is applied to the crimped body. A method for producing coated paper, which comprises irradiating the paper, and then peeling off and removing the carrier film. 2. The method for producing coated paper according to claim 1, wherein the ionizing radiation curable resin is a polyether polyurethane resin or a polyester polyurethane resin having an acroyl group or a metaacroyl group. 3. The coating agent contains a photopolymerization initiator selected from acetophenones, benzoin alkyl ethers, benzyl ketals, or ketones, and the ionizing radiation is not irradiated from the surface of the carrier film. A method for producing coated paper according to claim 1 or 2, which is carried out by irradiation with ultraviolet rays. 4. The coating according to claim 1, 2, 3, or 4, wherein the carrier film is a biaxially oriented polypropylene film, a biaxially oriented polyester film, or a biaxially oriented polyamide film. Paper manufacturing method. 5. The method for producing coated paper according to claim 3 or 4, wherein the carrier film has a UV transmittance of 20% or more in the wavelength range of 250 to 400 nm.