JPH0362871A - Adhesive and production of laminate by the same adhesive - Google Patents

Abstract

PURPOSE:To obtain an adhesive useful for producing laminates, not requiring an aging process, having a short production process free from a problem of smell resulting from residual solvent or residual monomer, comprising a solution of ultraviolet-curing resin containing a deodorant in alcohol solvent, etc. CONSTITUTION:The objective adhesive comprising a solution of ultraviolet-curing resin containing a deodorant (e.g. mixture of calcium phosphate and zinc oxide) in an alcohol solvent or water-alcohol solvent, preferably containing a hydrogen draw type photopolymerization initiator (e.g. 3,3-dimethyl-4-methoxy- benzophenone). The back of material is coated with the adhesive, and after evaporation of an alcohol, etc., as the solvent, a film for sealant (preferably one having >=20% ultraviolet percent transmission at 250-400nm) having thermally welding performances is stuck fast to the coated surface of the adhesive, and further the film surface is irradiated with ultraviolet rays to give a laminate.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to an adhesive using an ultraviolet curable resin and a method for producing a laminate using the adhesive.

[Prior Art] Laminated sheets, in which films or sheets with different properties are adhered with adhesives, are often used for the purpose of providing various performances.

In particular, laminated sheets using hardening resin adhesives are used as packaging materials to obtain highly flexible packaging (flexible packages).For example, isocyanate hardening polyether polyurethane resins are used as packaging materials. Adhesives made of a two-component curable resin using an organic solvent, etc., and adhesives made of an ultraviolet curable resin, a photopolymerization initiator, and a polymerizable monomer component as a diluent are used.

[Problems to be Solved by the Invention] By the way, adhesion using the above-mentioned two-component curable resin adhesive involves pressing the object to be adhered closely against the surface coated with the adhesive, and then holding it for one week. The above-mentioned aging curing process is required, and the manufacturing efficiency of the laminate is extremely low, which not only makes it impossible to meet quick delivery dates, but also requires equipment for the aging process, which is non-conforming. It also has the disadvantage of being economical.

In addition, when using an adhesive made of an ultraviolet curable resin and a photopolymerization initiator that uses a monomer component as a diluent, it is inevitable that low molecular weight substances remain due to the monomer component that is the diluent. This has become a hygiene problem for laminated sheets that are often used for packaging snack foods and the like.

In contrast, the present invention does not require a long-term curing process due to aging when obtaining a laminate, and does not use a diluent based on monomer components.
for example.

An adhesive that does not generate odors due to decomposed products of the photopolymerization initiator generated by irradiation with ultraviolet rays, such as cyclohexanone, benzaldehyde, methyl benzoate, etc., when it contains a self-cleavage type photopolymerization initiator; The present invention provides an efficient method for manufacturing a laminate using the adhesive.

"Means for Solving the Problems" The adhesive of the invention of wooden tablet 1 is made of an alcohol solvent or water-alcohol solvent solution of an ultraviolet curable resin containing a deodorizing agent.

In addition, the invention of wooden tablet 2 is a method for manufacturing a laminate of a base material and a sealant film having thermal welding performance, which includes the step of applying the adhesive of the invention of wooden tablet 1 to the back surface of the base material; a step of evaporating and drying alcohol or water-alcohol, which is a solvent in the applied adhesive, and a step of bringing a sealant film having thermal welding performance into close contact with the coated surface of the adhesive, and further, The method includes a step of irradiating ultraviolet rays from the surface of the sealant film.

Furthermore, the method for producing a laminate of the base material of the invention of wooden tablet 3 and a sealant film having thermal welding performance is as follows:
In the structure of the method for producing a laminate according to the invention, a film having an ultraviolet transmittance of 250 to 400 nm of 20% or more is used as the sealant film.

In the actual invention having the above configuration, the ultraviolet curable resin includes, for example, epoxy (meth)acrylate, polyurethane [meth)acrylate, polyolefin glycol (meth)acrylate, polyester (meth)acrylate-1-, etc. with a molecular weight of 300 to 6,000, preferably from 1,000 to 3,000, having two or more polymerizable functional groups, specifically, one type or a mixture of two or more of oligomers having an acrylic double bond is used. be done.

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, such as 2-hydroxyethyl (meth)acrylate, and a polyolefin glycol ( Examples of meth)acrylate include di(meth)acrylic acid ester of polyethylene glycol, etc.
Further, as the polyester (meth)acrylate, a reaction product obtained by treating a polyester of fucuric anhydride and diethlene glycol with (meth)acrylic acid is used.

Further, the solvent in the adhesive includes, for example, a single solvent, a mixed solvent such as isopropyl alcohol, ethyl alcohol, methyl alcohol, butyl alcohol, and further,
A mixed solvent of the above-mentioned alcoholic solvent and water is used, and in the case of a water-alcohol mixed solvent, a mixed solvent of about 10 to 1000 parts by weight of water to 100 parts by weight of alcohol is used.

Furthermore, it goes without saying that the adhesive contains an ordinary photopolymerization initiator, and for example, ordinary photopolymerization initiators such as benzoin alkyl ether, benzophenone, and benzoin are used. .

It should be noted that, of course, a photosensitizer such as dimethylaminoethanol, triphenylphosphine NN-dimethylaniline, dimethylaminobenzoic acid ester, etc. may be used in combination with the photopolymerization initiator, if necessary. be.

Furthermore, the deodorizing agents contained in the adhesive include, for example: 1) Physical adsorption deodorizing agent Neutral activated carbon, zeolite, activated alumina, acid clay, etc. 2) Chemical deodorizing agent Acidic agent, back alkaline agent, Oxidizing agent reducing agent 3) Physical/chemical deodorizer Alkaline or acidic impregnated activated carbon.

Zeolite 1-2 adsorbed with vegetable essential oils, etc. 4) Other iron phthalocyanine derivatives, salts with desulfurization properties such as zinc oxide, mixtures of iron (II) compounds, L-ascorbic acid, alum, etc., etc. 1 or 2) Mixtures of more than one species are used.

The adhesive of the present invention having the above composition usually contains 0.5 to 1 part of photopolymerization initiator per 100 parts by weight of the resin component.
0 parts by weight, 50-1000 parts by weight of solvent, 00 parts by weight of deodorizer
It is used as a composition containing about 1 to 5 parts by weight, and in particular, when the deodorizing agent exceeds 5 parts by weight per 100 parts by weight of the resin component, the adhesive strength of the adhesive decreases. Therefore, the amount of the deodorizing agent added is preferably 5 parts by weight or less per 100 parts by weight of the resin component.

In addition, the adhesive may be applied to a coated surface of 0.5 to log on the base material by a coating method such as gravure coating, direct coating, reverse roll coating, etc.
(solid component)/m2.

The base material in the method for manufacturing a laminate of the present invention using the adhesive includes, 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. A laminated film made of the above film and metal foil, paper, etc. is preferably used, and it goes without saying that the base material may be given design characteristics by printing or the like, if necessary.

Further, the sealant film that is bonded to the base material using the above-mentioned adhesive includes, for example, a low-density polyethylene film.

Medium-density polyethylene film, high-density polyethylene film Polyolefin resin films such as ethylene-vinyl acetate copolymer film, ethylene-α-olefin polymer film, and unstretched polypropylene film are used.

Note that the method for manufacturing a laminate using the base material and the sealant film is to apply the aforementioned adhesive to the base material surface, and then remove the solvent in the adhesive applied to the base material surface by blowing hot air, for example. After that, the sealant film is brought into close contact with the coated surface of the adhesive, and ultraviolet rays are irradiated from the surface of the sealant film. Ultraviolet irradiation treatment is performed using a mercury lamp, 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 irradiation dose may be insufficient,
If the adhesive is insufficiently cured and the irradiation processing speed is too slow, the heat and ultraviolet rays from the ultraviolet lamp may cause the sealant film to curl as the film shrinks and reduce heat-sealing performance. Therefore, in terms of lighting, the output of the ultraviolet lamp is 80 to 120 w/cm, and the irradiation speed is 20 to 150 m/m.
It is preferable to irradiate ultraviolet rays at a wavelength of about 100.degree.

"Examples" Hereinafter, specific configurations of the adhesive of the present invention and the method for manufacturing a laminate using the adhesive will be described with reference to Examples.

Example 1 From a biaxially stretched polyester film with a thickness of 25 IL which has been printed by back printing, 3 g (solid) of an adhesive having the following composition was applied to the printed surface of the base material by gravure roll coating. Ingredients) 7m
2 parts, and then apply 80 parts to the adhesive coated surface.
By blowing hot air at .degree. C. for 0.2 seconds, isopropyl alcohol, which is a solvent in the adhesive, was evaporated and dried to form an adhesive layer consisting of a coating layer of ultraviolet curable resin.

UV curable resin [Polyether-based polyurethane diacrylate prepared by treating a reaction product of polyethylene glycol and tolylene diisocyanate with hydroxyethyl acrylate: average molecular weight 3000] ...30 parts by weight Photopolymerization initiator [benzoin isopropyl ether] 1 part by weight photosensitizer [p-dimethylaminobenzoic acid ethyl ester] 1 part by weight isopropyl alcohol...69 parts by weight Deodorizer -... ...1 part by weight [mixture of calcium phosphate and zinc oxide] Next, a sealant film made of a low-density polyethylene film with a thickness of 60 μm was brought into contact with the surface of the coating layer of the adhesive made of the ultraviolet curable resin, and then , crimped with nip rolls, followed by high pressure mercury lamp [80w/cm,
Lamp length: 90cm, distance to sealant film (10cm), irradiation speed (Nippon Battery Co., Ltd.)
Ultraviolet rays were irradiated at a line speed (line speed during irradiation) L OOm/min from the surface of the sealant film to obtain a laminated sheet as the desired product.

Comparative Example 1 Adhesion was carried out using an adhesive to which no deodorizing agent was added in the composition of the adhesive used in Example 1, and the other components were all the same as in Example 1. Through the process, a laminated sheet for comparison was obtained.

Comparative Example 2 Using the same base material as that used in Example 1, the printed surface of the base material was coated with incyanate-curing polyether polyurethane resin "Takelac A-969 Takenate" using ethyl acetate as a solvent. A-5: Takeda Pharmaceutical Company (
Co., Ltd.' adhesive was applied at a ratio of 3 g (solid component) to 7 m2, and then a layer of 60 mm thick was applied to the surface of the adhesive coating layer.
A sealant film made of μ low-density polyethylene film is brought into contact with the sealant film, and then the sealant film is pressed with a nip roll, and then the film is heated to 40°C.
A laminated sheet for comparison was obtained by aging for 7 days.

"Experiment 1" Each of the laminated sheets obtained in Example 1 and Comparative Examples 1 and 2 was cut into a narrow tape shape with a width of 15 mm, and a peeling angle of 90 mm was applied between the base material and the sealant film. The peel strength was measured at a peeling speed of 300 mm/min.

"Experiment 2" Each of the laminated sheets obtained in Example 1 and Comparative Examples 1 and 2 was cut into 10100 x 100 pieces, and 5 pieces of each type were sealed in a 200 mg Erlenmeyer flask with a stopper. '
After leaving the flask open for 1 hour, the odor inside each flask was evaluated by sensory evaluation.

The results are shown in Table 1 together with the peel test results of Experiment 1 above.

Table 1: A severe odor was generated due to the decomposition product of the photopolymerization initiator "Operations and effects of the invention" The adhesive of the present invention is made of an alcoholic solution or a water-alcoholic solution of an ultraviolet curable resin. In the bonding process using this adhesive, for example, there is no need to go through the aging process that is required when using a two-component hardening resin adhesive, and the manufacturing process is extremely shortened, so it can be completed within a short period of time. In addition, since the adhesion condition can be inspected immediately after the adhesion process, production control is easy. .

Furthermore, since the adhesive of the present invention is made of an alcoholic solution or a water-alcoholic solution of an ultraviolet curable resin and tends to contain a deodorizing agent, the resulting laminate may contain residual solvent or There is no odor caused by monomers or decomposed products of the photopolymerization initiator generated by ultraviolet irradiation, such as cyclohexanone, benzaldehyde, methyl benzoate, etc., and it has an extremely excellent effect in terms of odorlessness. Furthermore, the viscosity of the adhesive can be easily adjusted, and the conventional
Compared to adhesives made of component-based curable resins, it is possible to obtain adhesive strength that is comparable in no way.

Furthermore, the method for producing a laminate of the present invention exclusively effectively utilizes the characteristics of the adhesive of the present invention,
Effects of obtaining a laminate using an efficient adhesion method, and without problems with residual solvents or residual monomers, and without problems with odor caused by decomposition products of photopolymerization initiators caused by ultraviolet irradiation; The effect will be produced.

Claims (1)

[Scope of Claims] 1. An adhesive comprising an alcohol solvent solution or a water-alcohol solvent solution of an ultraviolet curable resin containing a deodorizing agent. 2. After coating the adhesive according to claim 1 on the back side of the base material, evaporate the alcohol or water-alcohol that is the solvent in the coated adhesive, and then 1. A method for producing a laminate, comprising: bringing a sealant film having thermal welding performance into close contact with a surface coated with an adhesive, and further irradiating ultraviolet rays from the surface of the sealant film. 3. 250-400nm in sealant film
Claim 2 in which the ultraviolet transmittance of is 20% or more
2. Method for manufacturing a laminate described in Section 1.