JPS58108276A - Ionizing radiation curing-type pressure-sensitive composition - Google Patents

Abstract

PURPOSE:To obtain hot-melt-type titled composition with high stickiness, adhesive and cohesive ability, by incorporating a specific amount of an acrylic monomer having a particular functional group in a copolymer made of from a specific proportion of butyl acrylate and vinyl acetate. 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) 50-90pts.wt of butyl acrylate and (ii) 10-50pts.wt of vinyl accatate with (B) 5-40pts.wt of an acrylic monomer having a functional group of formula (R is 2-14C alkyl in which one H atom is substituted by OH-, carboxyl-, amino-, epoxy- or cyano- group) (e.g. acrylic acid, N,N'- dimethyl-acryamide). For the component B, it is preferable to use a monomer whose homopolymer has a glass-transition point of -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 relates to a hot-melt adhesive composition that provides an adhesive layer or a pressure-sensitive yellow layer by polymerizing or crosslinking by irradiating with ionizing radiation after coating.

Conventionally, pressure-sensitive adhesive tapes or sheets have been made by coating a base material with an adhesive solution and then heating and drying it, but this method uses a large amount of solvent, so it is difficult to avoid flammability, toxicity, etc. 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 those listed in F. But what about the water contained in emulsion type adhesive?
Because it is heated and dried, the drying time is long and energy consumption is large; water resistance is poor because it contains activators and stabilizers Y during synthesis; be. In addition, hot melt adhesives are attracting particular attention due to their advantages such as non-pollution and high speed.
The main constituent raw material for this is synthetic rubber (I), which has the disadvantage of poor weather resistance characteristic of rubber-based adhesives, as well as the fluidity that allows it to be applied at high temperatures. Because of this, there is also an interlayer point where the heat resistance is inferior. In addition, acrylic hot melt adhesives, which have been attracting attention recently, must have a fluidity Y that can be applied at high temperatures, similar to the case with rubber hot melt adhesives. Due to the essential conditions required, it is ionizable to use a polymer that is sufficiently crosslinked and has a high molecular weight.
Adhesive with good contact force and cohesive force! There is a problem in that it is difficult to apply, and a product with sufficient performance Y has not yet been obtained.

In order to improve the above-mentioned drawbacks of acrylic hot-melt adhesives, a monopolymer is added as a diluent to an acrylic paste polymer similar to that used in conventional acrylic hot-melt adhesives. Acrylic monomer! Adjust the viscosity by adding more! Furthermore, after coating, the adhesive layer is irradiated with ionizing radiation (Y) to cross-link and polymerize the acrylic paste polymer and the polymerizable acrylic monomer (V) with each other. Although this method is widely known, it has not yet been put into practical use.

The present invention has been made as a result of studies in view of the above-mentioned conventional drawbacks, and by adopting the structure described in claim (1), the present invention overcomes the conventional drawbacks and provides sufficient adhesive strength and adhesion. The present invention provides an acrylic hot-melt viscous composition Y having strength and cohesiveness.

The structure of the present invention will be explained in detail below.
The main component is 9gt per serving], the molecular weight is s, ooo ~ 300. rl (111) Butyl acrylate Y is used because butyl acrylate polymers not only inherently provide excellent viscosity but also have excellent weather resistance, and vinyl acetate V is used. Since the glass transition temperature of the polymer is high and it is easy to crosslink, it is effective in increasing the cohesion of the adhesive during copolymerization, and at the same time provides crosslinking points when irradiated with ionizing radiation, resulting in increased sensitivity to ionizing radiation. This is because the present inventors have discovered that the combination of butyl acrylate and vinyl acetate in the above copolymer contributes to increasing the adhesive strength, providing an adhesive with excellent cohesive strength, strong heat resistance, and solvent resistance. The composition of each is 50wt91-90wt-110vIIIll
l-~50111IIg is suitable, but this is l1v1
#If the blending ratio of vinyl is less than 10 times I-, a copolymer with sufficient cohesive force Y will not be obtained, and 5011% Y
This is because if it exceeds this, the molecular weight and cohesive force of the copolymer will increase too much, making it impossible to apply by hot melt. In addition to the above-mentioned main components, that is, butyl acrylate and vinyl acetate, the copolymer may further contain one or more acrylic monomers having a functional group such as the following, if necessary. There is no problem with acrylic monomers such as acrylic acid, methacrylic acid, glycidyl (meth), etc. Acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, dimethylaminoethyl (meth)acrylate, diethylaminoethyl (meth)acrylate, acrylamide, N,N-dimethylacrylamide, N-methylolacrylamide, diacetosoacrylamide,
Examples include N-tert-butylacrylamide and acrylonitrile. The above-mentioned combinations of ACTUL monomers and additives are particularly suitable for bonding to metals, glass, etc.; in particular, the adhesive force is improved by hydrogen bonding, etc., and it provides a so-called sticky adhesive. is preferable
Father, if the above-mentioned nanatsumer is added in excess of 20 parts by weight per 100 parts of the main component, the resulting copolymer will have an excessive cohesive force, and hot-melt application will become ionized, and at the same time the viscosity will increase. : Necessary and sufficient viscous force V cannot be obtained.

The molecular weight of the copolymer made as above is s, o'oo
~300.000 is required. This is because if the molecular weight of the copolymer is less than s, ooo, a sticky agent with sufficient adhesion and cohesive force cannot be obtained, and if it exceeds lO,000v, the adhesive composition containing the copolymer Y will not be able to be applied by ordinary hot melt coating. It does not have enough fluidity to be applied even to guests,
This is because hot melt coating becomes virtually impossible.

Next, the general formula used in the present invention (':H2'=CHC!OOR (where R is an acrylic acid having 2 to 14 carbon atoms in which one hydrogen is substituted with a hydroxyl group, a carboxyl group, an amino group, an epoxy group, or a cyano group) The acrylic acid ester monomer represented by the above-mentioned functional group-containing acrylic monomer can be used, for example, from among the acrylic monomers having a functional group of 21!1 or more, and 100 parts by weight of the copolymer described above can be used. 5-40 against
Parts by weight can be added. Such acrylic monomers are very effective in improving the adhesion between the pressure-sensitive adhesive layer and the adhered object, and one purpose of this effect is to improve the adhesion of the first component, the 4° C. It is also possible to step inside, and such attempts have been made in the past. However, in this case, when the weight fraction of the acrylic monomer having the above functional group in the copolymer increases, the cohesive force of the copolymer increases significantly, and the hot melt property increases by 7q af!
There was a problem that it was not possible to use an acrylic monomer having a sufficient amount of functional groups in the copolymer to obtain sufficient adhesion strength, since this would make it impossible to form a single cloth. . On the other hand, as the second ingredient, 1,000 tsuma is left as is.
Pressure sensitive adhesive 111.
! - Acrylic monomers having a sufficient amount of functional groups Y to obtain sufficient adhesion Y to the carboxylic material v Not only can this method be used without the need for ramie suitability wtf4; This makes it easier to achieve a low viscosity that can be dispensed without a solvent, and in the case of a hot-melt viscous IJII composition that does not use a conventional monomer, it has a high viscosity that makes it difficult to apply. Even polymers or copolymers that have never been used before can be easily fabricated by hot melting. Also, by applying this method to W, I+.

When the hot-melt coating layer of such an adhesive composition is irradiated with ionizing radiation, the acrylic monomer having the functional group Y is exposed to side chains in the copolymer. v By cross-linking, a pressure-sensitive adhesive can be obtained which has significantly superior cohesive strength and strong heat resistance and cracking resistance compared to the case where no monomer is present and the side chains of the copolymer are cross-linked. becomes possible.

Acrylic Chinoto-1F 1ift with functional groups! 5 to 40** parts are required for 1 part of combined Inn, but this means that if the 5' is less than the ok part, the significant effect mentioned above will not be produced, and tf40 city forging. Part wt
*This is mainly because a pressure-sensitive adhesive with sufficient cohesive force and adhesive strength cannot be obtained.

Functional group? As the acrylic monomer, one or two or more of the acrylic monomers listed as examples can be used as appropriate. In order to obtain the acrylic monomer having the functional group Y, the glass transition temperature of the homopolymer is -1[1°C to 180°C].
It is preferable that the pressure-sensitive adhesive composition has a temperature of 1°C.
Known additives such as fillers and anti-aging agents may also be added.

The ionizing radiation-type adhesive composition of the present invention made of VIF can be applied to various films, papers, and the like.
. After melting and mixing them, apply them to a base material (or -1 release paper) such as laminate T, etc. is 1 each
1JI-Ne4) Keraminate or 1. < is applied to each Azusa base material (or @flllK), and the adhesive composition was coated on the hakama with @# paper (or various base materials) V-laminate l. and the composition V
By cross-linking and combining 2), compared to the conventional one *, l
It is a pressure-sensitive adhesive V that has excellent cohesive force and strong adhesive strength, excellent solvent resistance, high-temperature holding power, and weather resistance. Ru. , Wl# As sensitive radiation, X-rays, R-rays, electron S, etc. are recommended, but electron beams are preferable.As electron beams, Cockroft-Walton type, Bandeg 1F drop, both W411F pressure type, and insulated core transformer are used. The beam is emitted from a type, linear type, guinatron type, high frequency type, etc., and has an accelerating voltage in the range of 50 to 1nnnKAV, preferably L<$-j1rl[l to 4rllllKeV.

The adhesive composition of the present invention can be sufficiently crosslinked by using irradiation between 1 and 50 megarads, and can have various adhesive strength, tack, etc. It is also possible to obtain a pressure-sensitive adhesive Y having physical properties Y with different performances.

The present invention Y will be explained in more detail below with reference to Examples.

Example 1 2-hydroxyethyl acrylate (the homopolymer has a glass transition temperature of 11% by weight) was added to 100 parts by weight of the copolymer
5°C) 20 parts by weight of Y were added, heated to 150°C, melted and mixed, and then uniformly coated on a polyester film to a film thickness of 25 μm, with acceleration energy of 175 KeV in a nitrogen stream from the coating side. An adhesive film having a transparent pressure-sensitive layer Y was irradiated with an electron beam Y at an irradiation dose of 51 (rad). An adhesive film having a transparent pressure-sensitive layer Y was obtained. It is shown in Table 1.

To 100 parts by weight of the same copolymer as in Example 1, 20 parts by weight of N and -dimethylacrylamide (the glass transition temperature of the homopolymer is 89°C) was added, and the adhesive film Y was obtained in the same manner as in Example 1. .

Example 3 211 parts by weight of acrylic # (the glass transition temperature of the homopolymer is 1 od) was added to 100 parts by weight of the copolymer,
Thereafter, an adhesive film V was obtained in the same manner as in Example 1.

Example 4 Acrylic #Y acryloyloxyethyl mononacrenate (glass transition point of homopolymer is -4Q°C) Table 1 Same as Example 3 except that V was used. However, the viscosity was determined by the method specified in JIS-ZO237 According to the results, Y was measured with a 180° peeling force t and a peeling rate of 300 III/- against a stainless steel plate, and the tack was determined by the J. Dow method using a pole at an inclination angle of 30°, according to the method specified in JIS-ZO257. Tack test results are listed.

Claims (1)

[Claims] (1) 50 to 90 parts by weight of butyl acrylate and 410 to 50 parts by weight of vinyl acetate, 1 monomer as main component, Y molecular weight as starting material, s, ooo to soo, oo. 100 parts by weight of a copolymer of the general formula CH2 = CHCOOR (where R refers to an alkyl group Y having 2 to 14 carbon atoms in which one hydrogen is substituted with a hydroxyl group, a carboxyl group, an amino group, an epoxy group, or a cyano group). 1. An ionizing radiation-curable adhesive composition comprising 5 to 40I 11 parts Y of an acrylic acid ester monomer having a functional group Y represented by the following formula.