JPS59105068A - Electron beam curing adhesive for laminating - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a laminate shielding agent for plastic films, and is an adhesive that cures in a short time with an electron beam and can tear an adhesive layer that is flexible and exhibits high adhesive strength. provide the agent.

Methods for manufacturing plastic laminated films, which are widely used as packaging materials, include dry lamination, extrusion lamination, and wet lamination. All of them utilize adhesives, and polyurethane-based, polyacrylic ester-based, Epoquin-based, vinyl chloride/vinyl acetate copolymer-based, and isocyanate-based adhesives are often used.

However, since all of these adhesives use organic solvents such as ethyl acetate, methyl ethyl ketone, toluene, xylene, and hexanoate, these organic solvents volatilize during the bonding process and during drying, which can pollute the working environment. Not only does it worsen the situation, but it also requires heating the drying pot, which is uneconomical and dangerous. The use of large amounts of organic solvents causes air pollution and wastes resources, which is not desirable. Since organic solvents cannot be prevented from remaining in laminated film products, they are unsuitable for packaging products such as food products that are sensitive to solvent odors.

In addition to the general problems mentioned above, especially in high-barrier plastic film laminates,
The disadvantage is that adhesion takes time. This type of laminate is preferably done by dry lamination in order to obtain high bond strength, and the adhesive is usually a combination of liquid polyol and polyisocyanate with a binder resin that gives the initial tack. This is because a mixture is used. The curing of this adhesive is caused by the reaction between the hydroquine group of the polyol and the isocyanate group of the polyisocyanate to form a urethane bond, resulting in 1λ polymerization and crosslinking. - After the target 7. has no adhesive strength and can proceed to the next step only after the reaction is completed by standing for 5 to 7 days. It is not known until this period has elapsed whether or not the ramy-john was performed as expected, which is a real disadvantage in terms of quality control.

The present invention aims to improve the above-mentioned drawbacks by using an adhesive that is cured by electron beams. The 1E beam-curing adhesive is solvent-free and completely eliminates the problems associated with the use of solvents, and also cures in a short time, making it possible to achieve high productivity. In recent years, relatively small and inexpensive deuteron beam irradiation equipment has become available, so restrictions on equipment are disappearing, and it is no longer necessary to use a long furnace for drying solvent-based adhesives. It was an advantage.

In addition, since starting and stopping can be done instantaneously, process control is easy, and material loss is also reduced. For this reason, the use of electron beam curing has been widely explored, particularly in the production of laminate films for packaging materials.

However, with known electron beam curing type jv adhesives, the +jJ flexibility of the cured layer is low, and the adhesive strength has not reached a level sufficient to add t and 1°.

The present invention further improves this point.
Electron beam curing that cures in a short time with J)%! It is an object of the present invention to provide a laminating adhesive that maintains the advantages of the adhesive described above and has both high adhesive strength and flexibility of the cured layer. 10 to 95 parts by weight of acrylic monomer CH2:=CHCOO[L''0CONHR2 and one or two types of polyurethane resin, polyester resin, polyvinyl acetate resin, and acrylic resin each having a molecular weight of 5,000 to 500,000. The gist of the present invention is to provide an electron beam curing adhesive for laminate, characterized in that it contains 5 to 40 Kawabes.

Acrylic monomer e142= Di(C0OR' OC
o NHTL2 is, for example, an isonic acid alkyl ester, isocyanic acid cyclohexyl ester, or isocyanic acid phenyl ester, and the amount of hydroxyethyl acrylate, hydroxypropyl acrylate, or hydroxybutyl acrylate monomer used is 10 to 95 parts. is good. If it is less than 10 parts by weight, the adhesive force will be weak, and if it is more than 95 parts by weight, the cohesive force will be insufficient.

The second component, the molecule, is 5,000 or more.
The following polyurethane resins, polyester resins, polyvinyl acetate resins, and acrylic resins are included for purposes such as adjusting the viscosity of the adhesive and improving adhesion to plastic films, and the amount used is 5-4
A 0-fold, 1-size section is preferred. If the amount is less than 5 parts by weight, the effect of addition is insufficient, and if it exceeds 40 parts by weight, no improvement in adhesion is observed.

Polyurethane resins that can be used for the above purpose are generally obtained from polyurethane resins obtained by reacting polyester-type or polyether-type polyols with diisonite, and are monomers that are soluble in the acrylic monomer that is the main component of the adhesive. be. Examples of commercially available products include [-Desmocol 110], Desmocol 130, Desmocol 400, Desmocol 406, Desmocol 42.
0, 510 (linear polyurethane resin manufactured by Sumitomo Bayer Urethane), and U Nilaporan J (manufactured by E1 Polyurethane Industries).

Further, as the polyester resin, a polyester resin obtained by melt polymerization of a diol and a dicarboxylic acid ester or a direct polymerization method of a diol and a dicarboxylic acid, which is soluble in the above-mentioned acrylic monomer, is used. Suitable commercially available products are linear polyester resins such as ``1 Pylon'' (manufactured by Toyobo) and ``Vycil'' (manufactured by Gutdeyer).

Vinyl acetate (Pomopolymers of vinyl acetate or copolymers containing 5 moles or more, preferably 30 moles or more thereof, which are soluble in acrylic monomers are selected. ri” (Made by Block Chemical Co., Ltd.), “Gosenil” (Made by Nikki Gosei Co., Ltd.), “BAKE
A commercially available product such as LITEJ (manufactured by Unimen Carbide) is an example.

As the acrylic resin, l'' IJ-7- whose main component is acrylic ester or methacrylic ester
Of these, those that are soluble in the monomers mentioned above. Examples of commercially available products include "Acrybase" (manufactured by Genji Kasei) and "Paraloid" (manufactured by Rohm and Haas).

Furthermore, the electron beam-curable laminating adhesive of the present invention may contain an acrylic ester monomer for the purpose of adjusting the curing speed and improving the compatibility of each component. The acrylic acid monomers include methyl acrylate, ethyl acrylate, H(iso)-butyl acrylate, 2-ethylhexyl acrylate, isodecyl acrylate, lauryl acrylate, stearyl acrylate, ethylene glycol diacrylate, di[tricethylene glycol diacrylate] , (i) propylene glycol diacrylate, iopentyl glycol diacrylate, 1,6-hexanediol diacrylate, methyl triglycol acrylate), 1,5-bentanediol diacrylate trimethylolpropane triacrylate.

Methoxyethyl acrylate, n-butoxyethyl acrylate, ethylcarpitol acrylate, dipentaerythritol hexaacrylate, diethylaminoethyl acrylate, benzyl acrylate, tetrahydrofurfuryl acrylate, 2-hydroxyethyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxy- Examples include 3-phenoxypropyl acrylate, acryloyloxyethyl monosuccinate, and acryloyloxyethyl monophthalate. The amount of the acrylic acid ester monomer added is at most 80 parts by weight, preferably at most 40 parts by weight and 11 parts by weight.

If the amount added exceeds 80 parts by weight, the urethane bond a PI in the adhesive will be low, resulting in a decrease in adhesive strength.

When it is urgent to improve the preservability of the adhesive, it is recommended to add a polymerization inhibitor such as hydroquinone or catechol in an amount of about 1.0 to 0.5 times. In addition, adhesives can be used as desired. 71
You can also add F, which has a calm and natural face.

The adhesive of the present invention is mainly used for laminating plastic films of the same or different types, but is also useful for laminating paper, metal foil, and plastic films with them.

Applicable to a very wide range of plastic films, examples include cellophane, low, medium and high density polyethylene, polypropylene, copolymers of ethylene with other α-olefins, ethylene-vinyl acetate copolymers, ethylene-vinyl acetate copolymers, etc. Stretched or unstretched films of vinyl alcohol copolymers, poly-9-1,2-butadiene, polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, polyethylene terephthalate, polyamide, polycarbonate, polyacetate and ionomer resins, and on these plastic films. These include those coated with polyvinylidene chloride, and those coated with a vapor-deposited film of metal such as aluminum. If a higher adhesive strength is desired, it is recommended to perform corona discharge treatment before applying the adhesive.

In order to laminate a film using the adhesive of the present invention, first, the entire surface or any part of the base film is laminated.
Gravure coating method, roll coating method, Plexo reverse method, etc., can be used to apply adhesive at 0.2 to 20 f! /m2,
Preferably 0.4-10F! /m' and laminated with another film (which may be of the same or different type as the base film) or by extruding other materials onto the film and laminating. , a step of curing the adhesive by irradiating it with an electron beam.

To laminate three or more layers, the above method can be repeated using the two-layer laminate film obtained as described above as a base material, or the three or more layers can be laminated using the adhesive of the present invention. The adhesive between each layer may be cured all at once by stacking the layers and irradiating the layers with a single electron beam.

The electron beam for curing the adhesive is emitted from various electron beam accelerators and has a voltage of 50 to 1000 KeV, preferably 100 KeV.
~3 Q Q Use something with an energy of KeV. The adhesive layer is irradiated either by a fast scanning spot beam or by a curtain beam. Normally, surface irradiation can be performed by continuously moving the object to be irradiated.

As described above, according to the present invention, a laminate film can be produced industrially advantageously using a solvent-free adhesive. Product laminate films are extremely useful as packaging materials, especially for packaging various foods, medicines, and the like.

Example 1 100 parts by weight of methyl isocyanate was added dropwise to a mixture of 205 parts by weight of 2-hydroxyethyl acrylate and 0.1 parts by weight of dibutyltinsilaurylate while stirring. At this time, the reaction was carried out while maintaining the reaction temperature below 60°C to form methylcarbamoyloxyethyl acrylate (CH2-=CHCOOC2H40CONHC) (
, )-i obtained. Polyurethane 'fff'J was added to 90 parts by weight of the obtained methylcarbamoyloxyethyl acrylate.
An adhesive composition was obtained by dissolving 10 parts of a resin (7':x, MOL 130, manufactured by Sumitomo Bayer Urethane).

The above adhesive was applied in an amount of 2.52 μm to a biaxially oriented polyethylene terephthalate film (“Lumirror” manufactured by Toshi Co., Ltd., thickness 16 μm) by an offset gravure method, and then a 40 μm thick polyxtyrene film was applied on top of it. Pasted together.

While winding this bonded film at a speed of 30 m/min, it was exposed to 15 Q KeV, 15
The adhesive was cured by irradiation with a dose of 3 Mrad under rnA conditions.

The adhesive strength of the laminate film produced in this manner was measured using a Tensilon at a tensile speed of 501 minutes and a peeling and unraveling angle of 90° (T-shape).

Adhesive strength is 430! /15M or more in width, and the film broke during peeling.

Examples 2 to 4 The same operations as in Example 1 were performed and the results of lamination are summarized in the following table.

Abbreviations in the table have the following meanings.

ON (16): Stretched nylon (thickness 16μ) C
P P (60): Unstretched polypropylene (thickness 6
0μ) PET (12): Stretched polyethylene terephthalate (thickness 12μ) PE (40): Unstretched polyethylene (thickness 40μ) OPP (20): Stretched polypropylene (thickness 20μ)

Claims (1)

[Claims] - [Acrylic monomer 10 represented by the formula 114]
~951 f, 4 parts ei+2=C11 (U001 also '0CONHI72 and H molecule Fit of one or more polyurethane resins, polyester resins, polyvinyl acetate resins, and acrylic resins with a molecular weight of 5.000 to 500,000. 5 to 40 seeds
11-ion beam curing characterized by containing a large amount]