JPS58108278A - Ionizing radiation curing-type pressure-sensitive composition - Google Patents

Abstract

PURPOSE:To obtain titled composition of high cohesive ability, stickiness and solvent resistance, comprising a (co)polymer of a specific acrylic ester or a copolymer prepared from the above acrylic ester, vinyl acetate, etc. and a second polymer in a specific proportion. CONSTITUTION:The objective composition comprising (A) 60-95wt% of a (co) copolymer prepared from an acrylic ester of formulaI(e.g. R<1> is 2-14C alkyl) (e.g. butyl acrylate, 2-ethylhexyl acrylate) or a copolymer made up from (i) 60-95pts.wt of the above acrylic ester, (ii) 5-40pts.wt of a monomer selected from vinyl acetate, (meth)acrylic acid, 2-14C methacrylic esters and acrylamide, having a molecular weight 5,000-500,000 and (B) 5-40wt% of a second polymer prepared from a monomer of formula II (R2 is 1-8C alkyl, R3 is 2-4C alkylene; n is 1-10), having a molecular weight 130-2,000 and preferably (C) <=35pts.wt based on 100pts.wt. of the components A+B of an acryloyl group-contg. monomer (e.g. methyl acrylate).

Description

[Detailed description of the invention]

The present invention relates to a hot-melt adhesive composition that is cured by irradiation with ionizing radiation after coating to provide a pressure-sensitive adhesive having excellent physical properties. Conventionally, pressure-sensitive adhesive tapes or sheets are made of rubber-based or acrylic-based polymers that are dissolved in solvent or water.
It is made by applying the mixture onto a Y base material and drying it by heating. However, with this method, it is possible! ! Those that use solvents have various problems such as fire hazards and toxicity to workers, and those that use water also have long drying times and high energy consumption, and the resulting adhesive is There are problems such as a tendency to have poor water resistance and difficulty in processing onto a film base material. In recent years, hot-melt pressure-sensitive adhesives have been attracting attention in order to improve these problems. A hot-melt adhesive is solid at room temperature, but melts with heat to become liquid or fluid, and after being applied to a base layer in this state, it becomes solid again by cooling. In order to obtain a hot-melt filler with sufficient fluidity at the application temperature, it is necessary to use a low molecular weight polymer. At present, melt-type adhesives have not yet been put into practical use. In contrast, hot-melt pressure-sensitive adhesives cured by ionizing radiation have recently been studied. This was devised to improve the drawbacks of conventional hot-melt adhesives, and is made of acrylic polymers diluted with acrylic monomers, which allows for adjustment of the viscosity that can be applied. It is polymerized or cross-linked by irradiation with ionizing radiation,
It is provided as an adhesive. However, many of the acrylic monomers used as diluents have low boiling points, which causes new problems such as odor, and no adhesive with sufficiently improved properties has been obtained. Recently, in order to improve the adhesive properties of pressure-sensitive adhesives, the use of acrylic monomers having a functional group i as a diluent has been studied, but no satisfactory results have been obtained yet. As a result of intensive research, the present inventors have found that by using a certain persimmon acrylic monomer or this and other acrylic monomers, it has a high boiling point and a mild odor, and also has the ability to reduce ionizing radiation. I) As a result of rapid crosslinking by irradiation, various performances such as adhesive strength and cohesive force are much improved compared to conventional products.
This has led to the creation of adhesive compositions that provide pressure-sensitive adhesives. That is, according to the present invention, a homopolymer of an acrylic ester represented by the general formula C)17=C'H100RI (where R1 is an alkyl group having 2 to 14 carbon atoms) or a solution of acrylic esters having different R1 is combined. copolymer or acrylic acid ester represented by the above general formula 60~
95 parts by weight and 1 to 40 parts by weight selected from the group consisting of vinyl acetate, acrylic acid, methacrylic acid, methacrylic acid ester having 2 to 14 carbon atoms, or acrylamide.
It is a copolymer obtained by solution polymerization with ij placement moiety, and is represented by a molecular weight of s, ooo to soo, oon polymer 60 to 95 weight, R2 is an alkyl group having 1 to 8 carbon atoms, and R5 is a carbon number 5 to 4 polymers with a molecular weight of 150 to 2000, where the alkylene group is a positive integer of 1 to 10 and the degree of polymerization is a positive integer of 1 to 10.
The present invention relates to an ionizing radiation-curable pressure-sensitive adhesive composition characterized in that it is a mixture consisting of 40% by weight. Below, each component used in the present invention will be explained.
The R1 component is a homopolymer of acrylic ester represented by the general formula 0H2=CHCjOOR' (where 1% is an alkyl group having 2 to 14 carbon atoms) or a copolymer of acrylic esters represented by R1. Acrylic acid ester polymers may be used, or acrylic acid ester polymers may be used, such as acrylic acid ester polymers, or combinations of esters and other heptamers represented by the above general formula. Examples of the acrylic acid ester homopolymer include a butyl acrylate homopolymer and a 2-ethylhexyl acrylate homopolymer. These polymers can be obtained by dropping a mixture of monomers, polymerization initiator 11, and chain transfer agent into a refluxing organic solvent such as ale, toluene, etc.
Examples of copolymers formed by solution polymerization of acrylic esters include: Examples include a copolymer of butyl acrylate and acrylic #2-ethylhexyl, a copolymer of 2-ethylhexyl acrylate and ethyl acrylate, and the like. These copolymers are
The latter acrylic ester copolymer can be obtained using exactly the same method as in the case of the acrylic ester homopolymer;
Examples include copolymers with methacrylic acid selected from acrylic acid, methacrylic acid, Nisder methacrylate having 4 to 12 carbon atoms, t-acrylamide such as diaseptone acrylamide, and methacrylamide. In the above acrylic ester copolymer, the raw material acrylic ester is 60 to 95 parts by weight, and if it is less than 60 parts by weight, it is impossible to satisfy the various physical properties required for the adhesive in a well-balanced manner, which is 95 parts by weight. In this case, the adhesive force to the adherend and the cohesive force of the adhesive itself become insufficient. In addition, in the above, the blending ratio of the first component is 60 to 9.
(I limited it to a range of 5 weight, but this is 6 oats)
If it is less than 951I-, it will not be possible to obtain an adhesive Y having sufficient cohesive force and adhesiveness, and if it is greater than 951I-, the viscosity of the composition will increase and it will be difficult to apply the composition to the substrate. At the same time, it is impossible to expect improvements in adhesive force and cohesive force, which are the effects of using the acrylic monomer as the second component described later. The second component constituting the composition of the present invention is mono-7-, which has a molecular weight of 130 to 2000 and is represented by the general formula where Th is represented by the following formula. . R2-0+R5,O÷, C-0H=CH2 (wherein, R2 is an alkyl group having 1 to 8 carbon atoms, R is an alkylene group having 2 to 4 carbon atoms, and n is 1 to 10, indicating the degree of polymerization V. The positive number Y and each R when n is greater than 1 may be the same or different.) The compound represented by the above general formula is represented by the following -
It is represented by formula 1 and can be produced by esterification of a -valent alcohol and acrylic acid or transesterification with a lower acrylic acid ester. R2-0(-R5-0-)-, H (However, the meanings of R2, R5 and n in the formula are the same as in the above formula (A)) Examples of the monohydric alcohol include methanol, ethanol, propatool, and alcohol. It can be obtained by adding a monoepoxide to a monohydric alcohol such as propatool, n-butanol, inbutanol, tert-butanol, or tert-butanol. Examples of monoepoxides include ethylene oxide,
Examples include propylene oxide, butylene oxide, ethylene oxide, 3-hydroxypropylene oxide, methyl glycidyl ether, ethyl glycidyl ether, butyl glycidyl ether, phenyl glycidyl ether, and the like. Monoepoxides can be used alone or in combination of two or more types. In the above, the range of nv1 to nv10 is limited to 1
If it exceeds 0V, the viscosity increases and the acryloyl group in the composition of the present invention becomes smaller, resulting in insufficient curing upon irradiation with ionizing radiation, making it impossible to obtain an adhesive with appropriate performance Y. This is because there is no In addition, in the above, the reason why the molecular weight is limited to the range of 1%'150 to 2000 is because the molecular weight of the compound represented by the general formula (to) with the smallest molecular weight is 130 (1), and when the molecular weight exceeds 2000V, the viscosity This is because as the acrylic monomer becomes higher, the number of acryloyl groups in the acrylic monomer, which is the second component, becomes smaller, resulting in insufficient curability. The third component constituting the composition of the present invention is one or more monomers having an acryloyl group Y other than the second component. As a specific example, acryloyl group w-4
For example, methyl acrylate,
Ethyl acrylate, propyl acrylate, butyl acrylate, hexyl acrylate, 2-ethylhexyl acrylate, dodecyl acrylate, benzyl acrylate, acrylic acid, glycidyl acrylate, 2-
Hydroxyethyl acrylate, 2-hydroxypropyl acrylate, dimethylaminoethyl acrylate,
diethylaminoethyl acrylate, acrylamide,
N, N-dimethylacrylamide, N-methylol acrylamide, diaton acrylamide, N-t
Examples include ert-butylacrylamide and acrylonitrile. ,! Examples of those having two or more F acryloyl groups Y include ethylene glycol diacrylate, propylene glycol diacrylate, neopentyl glycol cyacrylate, -t, j, 6-hexenediol diacrylate, diethylene glycol diacrylate, and triethylene glycol. Examples include diacrylate, dipropylene glycol diacrylate, and trimethylolpropane triacrylate F. In the adhesive composition of the present invention, a pressure-sensitive adhesive having sufficient adhesive force and cohesive force can be obtained even if the above-mentioned third component is not necessarily blended, but the third component may be added as appropriate. By blending, it is possible to provide various types of adhesives with the required physical properties. Also, as a third ingredient

By using an acrylic monomer having two or more acryloyl groups, it is also possible to cure with less irradiation 1v when curing with ionizing radiation. However, in order to obtain an adhesive with sufficient tackiness,
The amount of the third component added is preferably 351 parts or less per 1001 parts of the mixture consisting of the first component and the second component. In addition, WAI may be added to the above adhesive composition as necessary.
F11. Known additives such as fillers and anti-aging agents may also be added. The ionizing radiation crosslinking adhesive composition of the present invention prepared as described above is applied onto a base material (or release paper) such as various films or laminated materials, and is peeled off after irradiation with ionizing radiation. Paper (or various base materials) may be keraminated [, < means coated on various base materials (or release paper),
Release paper (or each S, S material) is applied to the applied surface of the adhesive composition.
After laminating, the composition is crosslinked and polymerized by irradiation due to its ionizing properties, resulting in a strong feel such as sufficient N strength, strong adhesive strength, and solvent resistance, which are not found in conventional products. A pressure sensitive adhesive can be obtained. As the ionizing radiation used in the present invention, X-rays, T-rays, electron beams, etc. can be used, but they have high transparency,
An electron beam capable of high-speed processing is preferable, and in the case of an electron beam, the electron beam can be of Cockroft-Walton type, Bumpgraph type,
Emitted from various electron beam accelerators such as resonant transformer type, insulated core transformer type, curve type, dynatron type, high frequency type, etc.
1000 KeV, preferably 100-300 KeV
Sufficient crosslinking can be achieved by using an irradiation dose r between 20 to 30%, and further, pressure-sensitive adhesives Y having various physical properties Y can be obtained by varying the irradiation dose. The present invention V will be explained in more detail below with reference to Examples. Example 1) 20 parts by weight of an acrylic monomer represented by the following formula were added to 100 parts by weight of a copolymer of 100 parts by weight, melted and mixed at 150°C, and uniformly spread on a polyester film to a thickness of 1x25μ. in a nitrogen stream from the Minefu side, acceleration energy 175 KeV, irradiation dose 5 Mrad,
It was irradiated with electron beams of 5 MrThd and 10 Mrad, respectively, to form a transparent pressure-sensitive viscous layer of 10%+>14. The viscosity and initial contact crack of the paper film thus obtained were measured and the results are shown in Table 1. Similarly, acrylic monomer glue 1 shown by formula (0)
Acrylic monomer V represented by the following formula (D) ~ Nail 1
A pressure-sensitive adhesive layer was obtained in exactly the same manner as in Example 1). The viscous force and initial adhesive force of these binding films vll
ll was determined and shown in Table 1. CJ-04-CH7-082-o-), C-cH=a
H2 mouth 0AH, -0-CH2-('!H2-0-C-
CH=CH2'((')06H*3 0(-CT-T
2 CH2o+,,c CH=OT(2ff)
1 Table 1 However, [2. The tack strength was measured according to the method specified in JIB-ZO237 at a peeling rate of 300 fins/- with 18o0 peeling on a stainless steel plate.
In accordance with the method specified in B-Z0237, the ball tack test results at an inclination angle of 50' by the J-Dow method are described.

Claims (1)

[Claims] (1) A homopolymer of an acrylic ester represented by the general formula OH2=0HOOORI (wherein R1 is an alkyl group having 2 to 14 carbon atoms), a copolymer obtained by solution polymerization of acrylic esters represented by R1, or the above-mentioned general 60 to 95 parts by weight of acrylic ester represented by the formula, vinyl acetate, acrylic acid, methacrylic acid, carbon number 2
A copolymer obtained by solution polymerization with 1 to 40 parts by weight of heptamine selected from the group consisting of methacrylic esters or methacrylamides of 1 to 14, and having a molecular weight of 5.00 to s
It is represented by 60 to 95 polymers of oo and ooo, R2 is an alkyl group having 1 to 8 carbon atoms, R5 is an alkylene group having 2 to 4 carbon atoms, and n is a positive integer of 1 to 10 indicating the polymerization number. be,
An ionizing radiation-curable adhesive composition characterized in that it is a mixture consisting of 5 to 40% by weight of a polymer having a molecular weight of 1330 to 2000. (2111! The ionizing radiation curing type described in Claim 1, P, characterized in that it is made by adding not more than 35 parts by weight of a monomer having an acrylic σ A/L group Y to 100 parts of the compound. Adhesive composition.