JPS58108277A - Ionizing radiation curing-type pressure-sensitive adhesive composition - Google Patents

Abstract

PURPOSE:To obtain titled composition of high stickiness, adhesivity and cohesive ability, by incorporating a specific amount of a particular acrylic ester in a copolymer made up from a specific proportion of butyl acrylate, vinyl acetate and an acrylic monomer having a specific functional group. CONSTITUTION:The objective composition can be obtained by incorporating (A) 100pts.wt of a copolymer having a molecular weight 5,000-300,000, made up from (i) 50-85wt% of butyl acrylate, (ii) 10-40wt% of vinyl acetate and (iii) 5-20wt% of an acrylic monomer having a functional group of formulaI(R<1> is 2-14C alkyl in which one H atom is substituted by OH-, carboxyl-, amino-, epoxy-, or cyano- group) (e.g. acrylic acid) with (B) 5-40pts.wt of an acrylic ester of formula II (R<2> is 2-14C alkyl) (e.g. dodecyl acrylate). For the component B, it is preferable to use a monomer whose homopolymer has a glass-transition point -10--80 deg.C. EFFECT:Having excellent solvent resistance and high weatherability, retaining high performance even at elevated temperatures.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention can be applied without a solvent, and after coating on a substrate,
The present invention relates to a hot-melt adhesive composition that provides an adhesive layer or a pressure-sensitive layer by polymerizing or bridging it by irradiation with release radiation.

Conventionally, pressure-sensitive adhesive tapes or sheets have been made by applying an adhesive solution to a base material and heating and drying it. However, in recent years, emulsion-type adhesives and hot-melt-type adhesives have been developed and put into practical use instead of solvent-type adhesives such as E. However, emulsion type adhesives contain water Y
Because it is heated and dried, it takes a long time to dry and consumes a lot of energy.It also contains an activator and a stabilizer Y during synthesis, so it has poor water resistance.

There are problems such as difficulty in processing onto a film base material. Hot-melt adhesives are attracting particular attention due to their advantages of being non-polluting and high-speed, but synthetic rubber is the raw material for their composition. In addition to the disadvantage of poor weather resistance characteristic of rubber-based adhesives, it also has the problem of poor heat resistance because it has fluidity Y that allows it to be applied at high temperatures. be. In addition, acrylic hot melt adhesives, which have been attracting attention recently, are hot melt adhesives that, like gono-type hot melt adhesives, must have fluidity of about 11 coatability at high temperatures. Due to the essential conditions required for the adhesive, it is difficult to use a polymer Y that is sufficiently crosslinked and has a high molecular weight Y. In order to improve the above-mentioned drawbacks of acrylic hot-melt adhesives, which have the problem of being difficult to apply and that no product with sufficient performance has yet been obtained, we have changed the conventional acrylic hot-melt adhesives. By adding a polymerizable acrylic monomer as a diluent to an acrylic base polymer similar to the one used, it is possible to easily adjust the viscosity that can be coated, and furthermore, after coating, A widely known method is to crosslink and move the acrylic base polymer and the polymerizable acrylic 7-mer Y by irradiating the adhesive layer with ionizing radiation, but this method has not yet been put into practice. It has not yet reached the level of A.

The present invention has been made as a result of studies in view of the above-mentioned drawbacks of the conventional art, and by having the structure set forth in claim (1) 1), the present invention overcomes the drawbacks of the conventional art and achieves sufficient adhesiveness. The present invention provides an acrylic hot-melt type viscous split silk composition having strength, adhesive strength, and NS chipping.

The structure of the present invention will be explained in detail below.

The base polymer taro copolymer used in the present invention is butyl acrylate 50-85-mono-1 vinyl acetate 10
〜4[1jlchi, and the general formula OH2””CHOOOR(
However, R is an alkyl group having 2 to 14 carbon atoms) and has a molecular weight of s=
It is a three-component copolymer of o n to 5 on nnn.

Butyl acrylate Y A is used because butyl acrylate polymers have excellent weather resistance and are not inherently sticky, and vinyl acetate V A is also used. Since the glass transition #l carbon is high and easy to crosslink, it is effective in increasing the cohesion of the adhesive during polymerization, and at the same time provides crosslinking points during irradiation with ionizing radiation, increasing the sensitivity to ionizing radiation. This is because the present inventors have discovered that this contributes to providing an adhesive having excellent cohesive strength and strong heat resistance and solvent resistance. The composition of butyl acrylate and vinyl acetate in the copolymer is 50 to 8511%, respectively, and 101 to 4%.
01kl- is appropriate, but if the blending ratio of vinyl acetate is less than 10% by weight, a polymer with sufficient cohesive strength cannot be obtained, and if it exceeds 5011F, the molecular weight and cohesive force of the polymer will increase. I) is too high, making it impossible to use hot-melt eyelid cloth. Another component constituting the copolymer is one or more acrylic monomers having a functional group in an amount of 511 to 2011III. The acrylic monomer having a functional group Y has the adhesive property Y between the pressure-sensitive adhesive layer and the object to be adhered.
Although it is added to improve the
If it is less than N-, no significant effect is observed, and 201
111G? If it exceeds this amount, the copolymer will have too much cohesive strength and cannot be applied by hot melt.

Sensuality 111. Examples of acrylic monomers having V include aryxyl acid, methacrylic acid, glycidyl acrylate, glycidyl methacrylate, 2-hydroxyethyl acrylate, 2-P drochylethyl methacrylate, 2-hydroxypropyl acrylate, and 2-hydroxypropyl acrylate. , diethylaminoethyl acrylate, dimethylaminoethyl methacrylate, diethylaminoethyl acrylate, C ethylaminoethyl methacrylate, acrylamide, N,N-dimethylacrylamide, N-methylolacrylamide, diacetonac9lua F, N-tert-butylacrylamide, acrylonitrile, etc. Being able to raise Y is a life saver.

The molecular weight of the co-vehicle body formed as described above must be in the range of 5.000 to soo, ooo. This is because the molecular weight of the copolymer is 5. If it is smaller than rlOO, it has sufficient cohesive force and viscous oak.

pressure sensitive adhesive V could not be obtained, and 3 oaooon
This is because, if V is exceeded, the pressure-sensitive adhesive composition containing the co-monomer V* will not have the fluidity V that allows coating at the coating temperature, and will not be able to be coated by hot melt.

Next, we will explain the acrylic ester represented by the general formula CH2"f'HCOOR (where R is an alkyl group having 2 to 14 carbon atoms) that is added to the combination. There are two advantages of using such an acrylic ester. One is that by adding an acrylic ester to the copolymer, which is the first component, it becomes easier to achieve a low viscosity that can be applied without a solvent, making it possible to create a hot-melt adhesive composition that does not require conventional monomers. In the case of products, it is now possible to apply hot-melt materials, even copolymers, which could not be applied due to their high viscosity.Another advantage is that hot-melt coatings can be Afterwards, when the eyelid layer is irradiated with ionizing radiation, the monomer cross-links the copolymer with each other. Compared to the case of crosslinking, it is possible to obtain a pressure-sensitive adhesive Y with far superior cohesive strength and strong heat resistance and solvent resistance.
1l or more than two gods? Copolymer 1001 which is the -th component
As stated above, 51 to 401111 parts per 1 part is used, which is less than 5 parts by weight.
No consistent effect was observed, and 4011flI! This is because if B is applied, a pressure-sensitive adhesive having sufficient cohesive force and viscosity cannot be obtained. Examples of acrylic acid ester monomers added for the above purposes include methyl acrylate, ethyl acrylate, propyl acrylate, 1pn-butyl acrylate, 1pn-butyl acrylate, tert-butyl acrylate, and hexyl acrylate. Acrylate, octyl acrylate, 2-ethylhexyl acrylate, nonyl acrylate, dodecyl acrylate, tetradecyl acrylate, hexytidecyl acrylate, benzyl acrylate, etc.
However, among these, the use of homopolymers with a glass transition temperature of 110°C to 180°C as the second component will increase the risk of agglomeration. First, it is more preferable in order to obtain a pressure-sensitive adhesive having sufficient initial adhesion.

Additionally, known additives such as plasticizers, fillers, anti-aging agents, etc. may be added to the pressure-sensitive adhesive composition as required.

The ionizing radiation-curable pressure-sensitive adhesive composition of the present invention prepared as described above can be applied to substrates (t or release paper) such as various films, papers, metal vapor-deposited 1'm thick films, and keraminated films thereof. ) After mixing each component (14 times), apply the adhesive composition to the adhesive composition, irradiate it with ionizing radiation, and then laminate it with a release paper (or various substrates) or apply it on various substrates (or release papers). Is there a release paper (or various base material) on the coated side? After laminating, the composition is crosslinked and polymerized by irradiation with ionizing radiation Y.
Sufficient cohesive force and strong stickiness not found in conventional products,
Furthermore, it is a pressure-sensitive adhesive that has excellent solvent resistance, high-temperature holding power, and weather resistance! ! can be done. Examples of ionizing radiation include X-rays, r-rays, and electron beams, but w-rays are preferred. The electron beam is emitted from various electron beam accelerators such as Cockroft-Walton type, Bumpgraph type, resonant transformation type, Zettai core transformation type, linear type, Dynatron type, and high frequency type, and has a power of 50 to 1000 KeV, preferably 100 KeV. A device having an accelerating voltage in the range of ~500 KeV is used.

The adhesive composition of the present invention can be sufficiently crosslinked by using radiation between 1 and 50 megarads, and can be sufficiently crosslinked to cause a change in p4A radiation of 1v to W. Pressure-sensitive adhesives with various unique physical properties have been developed by JIFIL? You can also get it.

Examples are given below), the present invention vw! This will be explained in detail.

Example 1) 20 parts by weight of dodecyl acrylate (glass transition temperature of homopolymer is -3°C) was added to 100 parts by weight of Yomo1 copolymer, and after melting and mixing at 150°C, 25 films were formed on a polyester film. It was applied uniformly to a thick layer, and irradiated with an electron beam Y at an acceleration energy of 175 KeV and an irradiation dose of 5 Mracl from the coating side in a nitrogen stream to form a transparent pressure-sensitive adhesive 11.
I got 11v.

The results of measuring the adhesive strength and initial contact force Y of the adhesive film thus obtained are shown in Table 1 together with other examples below.

Example 2) Butyl acrylate (glass transition point of homopolymer -54°C) was added to 100 layers of the same copolymer as Example 1.
A transparent pressure-sensitive adhesive layer Y was obtained in the same manner as in Example 1 except that 01 was added.

Example 3) Octyl acrylate (Tg of homopolymer is 165' (: ) 20
A transparent pressure-sensitive adhesive layer was obtained in the same manner as in Example 1.

However, the adhesive strength was measured by the J-Dow method according to the method specified in JIS-ZO257 against a stainless steel plate at a force of 180 cllll F and a peeling rate of 500 tj/-. The ball tack test results at an inclination angle of 50' are described.

Claims (1)

[Claims] (1) Butyl acrylate 50-851! set, vinyl acetate 10-401J set-1 and general formula CH2=O)100OR' (however, R1 is one of its hydrogen
A functional group represented by an alkyl group having 2 to 14 carbon atoms substituted with one hydroxyl group, carboxyl group, amino group, epoxy group, or cyano group? A molecular chain consisting of 5-20 19I acrylic esters aooo ~s
on, ooo copolymer 1001 and general formula CH
An ionizing radiation-curable adhesive composition comprising 5 to 4.0 parts by weight of an acrylic ester represented by 9=CHCOOR2 (where R2 is an alkyl group having 2 to 14 carbon atoms).