JPH03182350A - Preparation of coated paper - Google Patents

Abstract

PURPOSE:To obtain coated paper wherein polishing or matting is faithfully reproduced on the surface of a coating layer and the adhesive strength of the coating layer is excellent by a method wherein a coating agent consisting of an ultraviolet curable resin, a reactive monomer and a photopolymerization initiator is applied to a carrier film and, after drying, paper is brought into close contact with the carrier film to irradiate the coating layer and the carrier film is released and removed. CONSTITUTION:As an ultraviolet curable resin, a polyether polyurethane or polyester polyurethane resin having an acryloyl group or a methacryloyl group is used and, as a reactive monomer, monofunctional or polyfunctional acrylate selected from 2-ethylhexyl acrylate, diethylene glycol diacrylate and trimethylol propane triacrylate is used. A coating agent is adapted to the surface of a carrier film to form a coating layer and paper is brought into close contact with the surface of the coating layer and, further, the whole is irradiated with ultraviolet rays to cure the coating layer.

Description

Detailed Description of the Invention [Industrial Field of Application] 4゜5゜The present invention relates to a method for producing coated paper having a coating layer made of an ultraviolet curable resin, and relates to a method for producing coated paper having a coating layer made of an ultraviolet curable resin. The matte state is faithfully reproduced on the surface of the coating layer, and the coating layer is made of an ultraviolet curable resin that has excellent adhesive strength between the paper surface and the coating layer. To provide a method for easily and reliably obtaining coated paper.

[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 coating layer, for example, the adhesive strength between the paper surface and the coating layer is insufficient, or the surface of the coating layer is They had drawbacks such as insufficient smoothness, or the need for a long aging process following the coating process, making it impossible to deliver within a short period of time. .

On the other hand, the coated paper manufacturing method of the present invention does not require a long aging process following the coating process, so it is highly efficient and can be delivered within a short period of time. In addition, the adhesive strength between the coating layer and the paper surface is good, and the glossy or matte state on the carrier film surface is faithfully reproduced on the surface of the coating layer. The present invention provides a method for easily and reliably obtaining coated paper having a high quality curable resin coating layer.

[Means for Solving the Problems J The method for producing coated paper according to the invention of Water Bottle 1 includes applying a coating agent made of an ultraviolet curable resin, a reactive monomer, and a photopolymerization initiator to a carrier film, drying the coating agent, and drying the coating agent. A step of forming a coating layer with an ultraviolet curable resin, a step of bringing paper into close contact with the surface of the obtained coating layer, a step of irradiating ultraviolet rays from the surface of the carrier film, and peeling and removing the carrier film. By doing so, a coated paper having a coating layer made of an ultraviolet curable resin is obtained.

The method for manufacturing coated paper according to the invention of Water Bottle 2 is characterized in that, in the constitution of the method for manufacturing coated paper according to the invention according to Water Bottle 1, polyether polyurethane having an acroyl group or a metaacroyl group is used as the ultraviolet curable resin in the coating agent. It uses resin or polyester polyurethane resin.

Further, the method for manufacturing coated paper according to the invention of water bottle 3 is as follows:
2-ethylhexyl acrylate and diethylene glycol diacrylate as the reactive monomer in the method for producing coated paper according to the invention of 2 or the invention of water bottle 2.

and trimethylolpropane triacrylate.

Further, the method for manufacturing coated paper according to the invention of water bottle 4 is as follows.
In the method for producing coated paper according to the invention of 2 or the invention of water bottle 2, a biaxially oriented polypropylene film, a biaxially oriented polyester film, or a biaxially oriented polyamide film is used as the carrier film to which the coating agent is applied. .

Furthermore, the method for producing coated paper of the invention of Suitei 5 is a configuration of the method for producing coated paper of the invention of Suitei 1, the invention of Suitei 2, the invention of Suitei 3, or the invention of Suitei 4. 250 to 40
A film with a UV transmittance of 20% or more at 0 nm is used.

In the method for producing coated paper of the present invention having the above configuration, a plastic film is used as the carrier film to which the coating agent is applied, such as a biaxially oriented polypropylene film, a biaxially oriented polypropylene film, Biaxially stretched polyester films, biaxially stretched polyamide films, and the like are preferable because they have sufficient ultraviolet transmittance and mechanical strength.

In addition, when the surface coated with the coating agent on the carrier film is a mirror surface, the coated layer on the obtained coated paper becomes a glossy coated layer, and the surface coated with the coating agent on the carrier film is coated with sandblasting, In the case of a finely uneven surface such as a satin finish, the coating layer of the resulting coated paper becomes a matte coating layer.

Furthermore, since the coating agent applied to the carrier film is cured by ultraviolet irradiation from the surface of the carrier film, the carrier film has a 250 to 4
It is preferable to use a material having an ultraviolet transmittance of 20% or more at 00 nm.

In the method for producing coated paper of the present invention, the coating agent applied to the carrier film is made of an ultraviolet curable resin, a reactive monomer, and a photopolymerization initiator,
The ultraviolet curable resin includes, for example, epoxy (meth)
Molecular weight 300-6 by acrylate, polyurethane (meth)acrylate, polyolefin glycol (meth)acrylate, polyester (meth)acrylate, etc.
000, preferably an oligomer with a molecular weight of 1,000 to 3,000 and having two or more polymerizable functional groups, specifically 1 fl or 2 f of an oligomer having an acrylic double bond! Mixtures of the above are used.

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 isocyanate group at the end and a compound having a vinyl group and a hydroxyl group in the molecule, for example, 2-hydroxyethyl (meth)acrylate, and a polyolefin glycol (meth)acrylate. )Acrylates include di(meth)acrylic esters of polyethylene glycol, etc., and polyester(meth)acrylates include reaction products of polyesters made from phthalic anhydride and diethylene glycol treated with (meth)acrylic acid. things etc. are used.

Further, as the reactive monomer in the coating agent, for example, monofunctional acrylates such as 2-ethylhexyl acrylate and 2-hydroxylpropyl acrylate, and polyfunctional acrylates such as diethylene glycol diacrylate and trimethylolpropane triacrylate, etc. are used.

Furthermore, a conventional photopolymerization initiator such as benzoin alkyl ether benzophenone or benzoin is used in the coating agent.

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.

The coating agent usually consists of a composition containing 10 to 300 parts by weight of a reactive monomer and 0.2 to 10 parts by weight of a photopolymerization initiator, based on 100 parts by weight of the ultraviolet curable resin.

Further, the coating agent having the above composition may be applied to the surface of the carrier film, for example, by gravure coating or direct coating.

Depending on the coating method such as reverse roll coating, it is usually applied in an amount of about 0.5 to 30 g (solid component)/m2.

A coating agent having the above-mentioned composition is applied to the surface of the carrier film to form a coating layer, and then,
The coating layer is cured by bringing paper into close contact with the surface of the coating layer, and then irradiating ultraviolet rays from the surface of the carrier film.

The coating layer is usually cured using an ultraviolet irradiation device using a high-pressure mercury lamp, a metal halide lamp, or the like.

Furthermore, in the ultraviolet ray irradiation treatment step, if the ultraviolet ray irradiation treatment speed is too fast, the amount of irradiated cotton will be insufficient;
If the coating layer is not sufficiently cured or the irradiation processing speed is too slow, the heat and ultraviolet rays from the ultraviolet lamp will cause the carrier film to curl as the film shrinks. The output of the ultraviolet lamp is 80-120w/cra, the irradiation speed: 20-15
It is preferable to perform ultraviolet irradiation treatment depending on the degree of 0s/win.

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

EXAMPLE 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, at a rate of 5 g (solid component)/1. A coating layer of ultraviolet curable resin was formed.

Coating ratio 1 UV-curable resin [polyether-based polyurethane diacrylate average fraction 1:3000 prepared by treating the reaction product of polyethylene glycol and tolylene diisocyanate with hydroxyethyl acrylate] ...39 parts by weight Photoinitiator [benzoin isopropyl ether] ...1 part by weight Photosensitizer [p-dimethylaminobenzoic acid ethyl ester] ...1 part by weight Reaction Polyethylene glycol dimethacrylate co... 100 parts by weight Next, the surface area of the coating layer of the ultraviolet curable resin! A 400 g/l paperboard was brought into contact with the paperboard, and then crimped with a nip roll.
m, lamp length 2 90cm, Nippon Battery Co., Ltd.], distance to carrier film 11t: 10c@, irradiation speed (line speed during irradiation): 10011/ff
A 1-inch ultraviolet ray irradiation treatment was performed from the surface of the carrier film to obtain a laminated sheet of the carrier film and paperboard.

Subsequently, when the carrier film was peeled off and removed from the laminated sheet, the carrier film could be removed smoothly and a coated paper made of an ultraviolet curable resin 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 good.

Example 2 Coated paper, which is the target product of the method of the present invention, was obtained using the same configuration as the corresponding configuration of Example 1, except for using a carrier film made of polyethylene terephthalate film with a thickness of 25 μm. Ta.

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 to paperboard with a basis weight of 400 g/-.
It was directly coated by gravure roll coating at a rate of 5 g (solid component)/m'' to form a coating layer of ultraviolet curable resin.

Next, a coated paper for comparison was obtained by performing ultraviolet irradiation treatment under the same conditions as the ultraviolet irradiation treatment in Example 1 from the surface of the coating layer of the ultraviolet curable resin.

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 not sufficient.

[Operations and Effects of the Invention] The method for producing coated paper of the present invention includes coating a carrier film with a coating agent made of an ultraviolet curable resin, a reactive monomer, and a photopolymerization initiator, thereby applying the ultraviolet curable resin to the carrier film. After that, a base paper is brought into close contact with the surface of the coating layer, and then ultraviolet rays are irradiated from the surface of the carrier film, and then the carrier film is peeled off and removed.

Therefore, in the method of the present invention, the presence of the reactive monomer in the coating agent provides better adhesion between the coating agent applied to the carrier film and the surface of the carrier film. A coated paper that has a mirror surface or a coated top layer in which the state of the matte surface due to minute irregularities on the surface of the carrier film is faithfully transferred to the surface, that is, a coated paper that has a high quality glossy or matte surface. Coated paper is obtained.

Furthermore, since the method of the present invention uses a solvent-free coating agent, coated paper without odor due to residual solvent can be obtained.

Furthermore, in the method of the present invention, since the coating layer of the curable resin is cured by irradiation with ultraviolet rays, there is no need for an aging process for curing the resin, and delivery can be completed quickly. It is possible to produce a coated paper at a correspondingly high speed, and the adhesive strength between one paper and the coating layer is high.

Furthermore, since the method of the present invention utilizes a coating agent containing a reactive monomer, the viscosity of the coating agent can be easily controlled and provides excellent operability.

Claims (1)

[Claims] 1. A coating layer made of the ultraviolet curable resin is formed by applying a coating agent consisting of an ultraviolet curable resin, a reactive monomer, and a photopolymerization initiator to a carrier film and drying it. Then, after bringing paper into close contact with the coated layer surface, ultraviolet rays are irradiated from the carrier film surface, and then the carrier film is peeled off and removed. . 2. The method for producing coated paper according to claim 1, wherein the ultraviolet curable resin is a polyether polyurethane resin or a polyester polyurethane resin having an acroyl group or a metaacroyl group. 3. The coating according to claim 1 or 2, wherein the reactive monomer is a monofunctional or polyfunctional acrylate selected from 2-ethylhexyl acrylate, diethylene glycol diacrylate, and trimethylolpropane triacrylate. Manufacturing method of paper. 4. The method for producing coated paper according to claim 1, 2, or 3, wherein the carrier film is a biaxially oriented polypropylene film, a biaxially oriented polyester film, or a biaxially oriented polyamide film. . 5. The method for producing coated paper according to claim 1, 2, 3, or 4, wherein the carrier film has an ultraviolet transmittance of 250 to 400 nm of 20% or more.