JPS5924767A - Crosslinking adhesive - Google Patents

Abstract

PURPOSE:To provide a crosslinking adhesive excellent in adhesion, and heat resistance, especially in adhesion at low temperatures, consisting mainly of a copolymer of ethylene, an ethylenically unsaturated silane compd., an unsaturated glycidyl compd. and other ethylenically unsaturated compds. CONSTITUTION:The adhesive contains as main component a copolymer obtained by copolymerization of (A) ethylene, (B) an ethylenically unsaturated silane compd. (e.g. vinyltrimethoxysilane), (C) an unsaturated glycidyl compd. (e.g. glycidyl acrylate) and (D) other ethylenically unsaturated compds. (e.g. vinyl acetate). (B), (C) and (D) are contained in 0.01-5, 0.1-20 and 5-40wt%, respectively, based on the copolymer.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a crosslinkable adhesive, and more particularly to a copolymer of ethylene, an ethylenically unsaturated silane compound, an unsaturated glycidyl compound, and another ethylenically unsaturated compound. This invention relates to a crosslinkable adhesive comprising as a main component.

Conventionally, as this type of adhesive resin, Japanese Patent Application Laid-Open No. 48-1
No. 1388 discloses a copolymer of ethylene, an unsaturated glycidyl monomer, and other ethylenically unsaturated monof'L monomers. However, although the adhesive strength of this copolymer is excellent at room temperature, it has the disadvantage that it decreases significantly at temperatures above the melting point of the core copolymer. No. 51-20210 discloses that an olefinically unsaturated silane compound having a hydrolyzable organic group is grafted onto a copolymer of ethylene and vinyl acetate or a copolymer of ethylene and alkyl acrylate, and a silanol condensation catalyst is used. A method is disclosed for improving the heat resistance of the copolymer by crosslinking the copolymer by exposure to water in the presence of. Further, JP-A-56-8447 discloses a similar method for a copolymer of ethylene, an olefinically unsaturated silane compound, and an ethylenically unsaturated compound. However, although the heat resistance of these copolymers is improved by crosslinking, the adhesive strength itself cannot be said to be sufficient.

In view of the above points, the present invention provides a crosslinkable adhesive that has excellent N contact properties and also has excellent heat resistance by crosslinking, particularly a hot melt adhesive that has excellent adhesive workability at low temperatures. The present invention has been made for the purpose of providing, and as detailed below, the present invention is a copolymer of ethylene, an ethylenically unsaturated silane compound, an unsaturated glycidyl compound, and another ethylene ff1i 7+1 compound, , the content of 411 silane compound, unsaturated glycidyl compound and 1,000 other ethylenically unsaturated compound units is based on the copolymer weight, each from 0.01 to
It is a crosslinkable adhesive mainly composed of a copolymer of 5% by weight, 0.1 to 20% by weight, and 5 to 40% by weight.

The ethylenically unsaturated silane compound used in the present invention has the general formula R3i l and ny3-n (where R
represents an ethylenically unsaturated hydrocarbon group or a hydrocarbonoxy group, R' represents an aliphatic saturated hydrocarbon group, Y represents a hydrolyzable organic group, and 11 is 0, 1, or 2. ), specifically, for example, R75E vinyl, allyl, impropenyl, butenyl, cyclohexenyl, r-(meth)acryloyloxyfurovir, 1? : is methyl, ethyl, propyl, decyl, phenyl, and Y is methoxy, ethoxy, polmyloxy, acetoxy, peropionyloxy, alkyl or arylamino. Sometimes preferably CH2=CH81'(OA)a
(wherein A is a hydrocarbon group having 1 to 8 carbon atoms), specifically vinyltrimethoxysilane, vinyltriethoxysilane,
'It is also vinyltriacetoxysilane. Two or more of these ethylenically unsaturated silane compounds may be used in combination, if necessary.

The content of the ethylenically unsaturated silane compound unit is essentially 0.0'1 to 5% by weight based on the copolymer weight [amount]; (It is preferably 15 to 2% by weight. If it is less than 1.01% by weight, heat resistance will be insufficient even if crosslinked, and if it is more than 5% by weight, problems will occur due to the copolymer becoming three-dimensional.) The generation of molten material is observed, and good adhesive strength cannot be stably obtained.

The unsaturated glycidyl compound used in the present invention refers to a compound having one unsaturated bond copolymerizable with ethylene in one molecule and having one or more glycidyl groups, such as glycidyl of an unsaturated carboxylic acid. esters, glycidyl ethers of unsaturated hydrocarbons, etc. Specifically,
glycidyl acrylate, glycidyl methacrylate,
Examples include itaconic acid monoglycidyl ester, itaconic acid diglycidyl ester, allyl glycidyl ether, and 2-methylallyl glycidyl ether.

In addition, these unsaturated glycidyl compounds have a low free acid content in order to suppress the generation of insoluble matter due to the three-dimensionalization of the copolymer and eliminate the deterioration in moldability and adhesive workability caused by this. I like things jL<, specifically 100 ppm
Below, in particular, 50 ppm or less is preferable. Further, two or more of these unsaturated glycidyl compounds may be used in combination as necessary.

The content of the unsaturated glycidyl compound unit is essentially 1 to 20% by weight, and preferably 0.5 to 10% by weight, based on the weight of the copolymer. If the amount is less than 0.1% by weight, the adhesion will be insufficient, and if it is more than 20% by weight, the copolymerization reaction itself will become extremely unstable and often lead to abnormal decomposition reactions.

Other ethylenically unsaturated compounds used in the present invention include (a) vinyl esters of vinyl acetate, vinyl butyrate, vinyl pivalin, (b) methyl (meth)acrylate, and (meth)acrylic enzymes. ethyl,(
(meth)acrylic acid esters such as butyl acrylate, unsaturated carboxylic acids such as e9(meth)acrylic acid, maleic acid, fumaric acid, and (meth)acrylonitrile, such as (meth)acrylamide. (meta)
Examples include acrylic acid derivatives, vinyl ethers such as (e)vinyl methyl ether, and vinyl phenyl ether. Among these, preferred is (meta)a.

In addition, these other ethylenically unsaturated compounds
In order to suppress the generation of infusible substances due to the three-dimensionalization of 1i coalescence and eliminate the deterioration of molding processability and adhesive workability due to this, it is preferable to use one with a low free acid content.
o o ppm or less, particularly preferably 50 ppm or less. In addition, "(meth)acrylic acid" shall mean both acrylic acid and methacrylic acid. Two or more kinds of such ethylenically unsaturated compounds may be used in combination, if necessary.

The content of the other ethylenically unsaturated compound units is:
It is essential that the amount is 5 to 40% by weight, based on the weight of the copolymer, and preferably 10 to 30% by weight. 5 layers]
If the amount is less than 40%, adhesion at low temperatures is difficult.
If the weight is more than 40% by weight, it becomes difficult to obtain a copolymer having a high molecular weight in the copolymerization reaction, and as a result, if the weight is more than 40% by weight, the strength of the adhesive itself decreases.

The copolymerization of ethylene, the ethylenically unsaturated silane compound, the unsaturated glycidyl compound, and other ethylenically unsaturated compounds may be carried out under any conditions that allow copolymerization of the three.

Specifically, for example, the pressure is 500 to 4. oo.

Ky/crl, preferably 1,000-3,50
0 Kf/cA, a temperature of 100 to 400 °C, preferably 150 to 350 °C, in the presence of a radical polymerization initiator and, if necessary, a chain transfer agent, in a seed or tubular reactor, preferably a seed type reactor, in which each monomer is contacted simultaneously or stepwise.

Note that when an organic acid nohinyl ester compound is used as the other ethylenically unsaturated compound, the preferred polymerization temperature is 150 to 250°C, particularly 150 to 250°C, in order to suppress the generation of organic acids generated by thermal decomposition. 200° C. is preferred. In the present invention, any radical polymerization initiator and chain transfer agent known for use in homopolymerization or copolymerization of ethylene can be used. As the 1r initiator, lauroylno(-oxide, cyclopionyl peroxide, benzoyl peroxide, di-t-
Organic peroxides such as butyl-butyl-oxide, t-butylhydroperoxide, t-butylperoxyisobutyrate, molecular oxygen, and azo compounds such as azobisinbutyronitrile and azoisobutylvaleronitrile. . Examples of chain transfer agents include rough hydrocarbons such as methane, ethane, propane, butane, and pentane, α-olefins such as propylene, butene-1, and hexene-1, formaldehyde, acetaldehyde, and n-butyraldehyde. Examples include aldehydes such as acetone, methyl ethyl ketone, ketones such as cyclohexanone, aromatic hydrocarbons, chlorinated hydrocarbons, and the like.

As the crosslinkable adhesive of the present invention, in addition to the above copolymer,
A silanol condensation catalyst, which is generally used as a crosslinking catalyst for this type of silane modified product, is used.

The present invention generally targets silanol condensation catalysts that can be used as catalysts that promote dehydration condensation between silanols of silicone. Such silanol condensation catalysts are generally carboxylic acid compounds of metals such as pot, zinc, iron, lead, cobalt, organic hydrochloric acids, inorganic acids, and organic acids.

Specific examples of silanol condensation catalysts include diptyltin dilaurate, diptyltin diacetate, diptyltin dioctoate, dioctyltin dilaurate, stannous acetate, caprylic acid, lead naphthenate, zinc caprylate, and naphthenic acid. , ethylamine, dibutylamine, hexylamine, pyridine, sulfuric acid, inorganic acids such as hydrochloric acid, and organic acids such as toluenesulfonic acid, acetic acid, stearic acid, maleic acid, etc. Among these, tin carboxylic acid compounds are particularly preferred.

The necessity of a silanol condensation catalyst may be appropriately determined by a practitioner for a given catalyst for a given copolymer with reference to the Examples described below. Generally speaking, it is about 0.001 to 10% by weight, preferably 0.001 to 10% by weight based on the amount of copolymer.
01 to 5% by weight, particularly preferably 0.01 to 3% by weight,
It is.

The silanol condensation catalyst may be used in various purposeful ways depending on the purpose and form of use of the non-exploding 8A adhesive. For example, a masterbatch is prepared by blending a silanol condensation catalyst into a dispersion medium such as polyethylene or ethylene-vinyl acetate copolymer at a high concentration, and this is blended in advance into the copolymer before processing to a predetermined concentration. A method of applying the solution or dispersion to the surface of the copolymer or adherend after processing, etc.

As the crosslinkable adhesive of the present invention, an isocyanate compound is used instead of or together with the silanol condensation catalyst.

As the incyanate compound, those having two or more incyanate groups in one molecule are preferable, and specifically, methylene bis(4-phenylison-anate), tolylene diisocyanate, hexamethylene diisocyanate, Examples include polyisocyanate, a reaction product of tolylene diinocyanate and hexanetriol, and the like.

In the crosslinkable adhesive of the present invention, these isocyanate compounds have the effect of improving adhesive strength in addition to the effect of promoting crosslinking.

The incyanate compound may be used in the same manner as the silanol condensation catalyst, depending on the purpose and form of use of the adhesive of the present invention.

Furthermore, the crosslinkable adhesive of the present invention may contain various auxiliary materials such as tackifiers, mixable thermoplastics, stabilizers, lubricants, fillers, colorants, and the like.

Since the copolymer as the main component of the crosslinkable adhesive of the present invention has excellent adhesive properties, the crosslinkable adhesive can be used for metals such as iron, aluminum, stainless steel, and copper, polyolefin, polyamide, polyester, melamine resin, urea Jrl resin, etc. Suitable for use as adhesives for cutting resins, wood, paper, cellophane, glass, asbestos, especially as hot melt adhesives. /)! First, the copolymer has excellent film formability, making it ideal as a film-like hot melt adhesive. Further, the crosslinkable adhesive of the present invention has a content and a molecular weight of other ethylenically unsaturated compounds in the copolymer of i+,! By adjusting the temperature, it can also be used as a solution adhesive.

In addition, the crosslinkable adhesive of the present invention has heat resistance by crosslinking the copolymer to a gel fraction of 5 to 90%, preferably 10 to 80% using the aforementioned silanol condensation catalyst, incyanate compound, etc. An excellent adhesive structure can be obtained.

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

Production details of the copolymer: A mixture of ethylene, vinyltrimethoxysilane, glycidyl methacrylate, 1-wave acrylic methyl or vinyl acetate, and propylene as a chain transfer agent is introduced into a 8Yl-5 liter stirred autoclave to initiate polymerization. 9/ails rli^ to a pressure of 2.600 by adding t-butyl peroxyimputylate as an agent.
Under conditions of 210°C, ethylene-vinyl trime I.
xysilane-glycidyl methacrylate-methyl acrylate copolymer (copolymer i to ■), ethylene-vinyltrimethoxysilane-glycidyl methacrylate-vinyl acetate copolymer (copolymer ■), vinyltrimethoxysilane, Ethylene-dalicidyl methacrylate-methyl acrylate copolymer (co-11 (combination v), ethylene-vinyltrimethoxysilane-methyl acrylate) without copolymerizing either glycidyl methacrylate, methyl acrylate, or vinyl acetate. Copolymer (copolymer■
) and ethylene-vinyltrimethoxysilane-glycidyl methacrylate polymer (copolymer ①) were each continuously produced.

Table 1 shows the polymerization conditions, and Table 2 shows the physical properties of the obtained copolymer.

(Leaving space below) Table 2 *1; Measured according to JIS K6760: Measured by fluorescent X-ray *3; Measured by infrared absorption spectrum Example 1 Copolymer ■ was previously coated with ethylene-vinyl acetate copolymer
Melt index 10? / 10 minutes, dibutyl dilaurate (vinyl acetate content 20% by weight) was added twice.
ii:% The kneaded masterbatch was tri-blended at 5 weight 70, and then put into a T-die film molding machine (extruder 65++n).
The crosslinkable adhesive was formed into a film having a thickness of 60 μm using a T-die effective width 800 arm) at a resin temperature of 220° C. and a molding speed of 30 m/min to obtain a film-like crosslinkable adhesive.

Next, prepare a birch veneer (moisture content: 8% by weight) sliced into 1.0 mm pieces, and apply the film-like crosslinking adhesive obtained earlier between the veneers to form a three-ply orthogonal plywood. Pressure 1 with heat press at 100℃ and 120℃
After crimping at 0 Kq/- for 3 minutes, it was cooled for 3 minutes at a pressure of 10 K9/crl in a cold press cooled with room temperature water (about 18°C). As described above, a 3-gly perpendicular plywood with a thickness of approximately 3.1 m was made.

Table 3 shows the measurement results of the adhesive strength of the plywood and the gel fraction of the adhesive.

In addition, the adhesive strength is determined based on the JAS general purpose board standard after the plywood is crimped and left in a constant temperature room at 40°C for 2 days.
The test piece is a piece of plywood with a width of 25 cm, in which the core is passed through the page and cuts reaching the adhesive surface are made at a distance of 13 mm from the front and back sides in the width direction. In addition, the test piece is immersed in 60×3°C warm water for 3 hours, then immersed in room temperature water until it cools down (hot and cold water immersion test), and the test piece is immersed in water at both ends every minute. This was done by tensing at a loading rate of 600 Kf or less and measuring the maximum direction and weight at the time of failure.

Separately, the previously obtained film-like crosslinkable adhesive was
0M1 width 25 body, 1mm thick cover veneer and same length,
Sandwiched between aluminum plates, iron plates, and nylon sheets each stacked 25 mm in width and thickness in the length direction, 10
Pressure 10 Kg/at 0℃ and 120℃ heat press
After crimping with tri for 3 minutes, the test piece obtained by cooling with a cold press was left in a constant temperature room at 40 ° C for 2 days after crimping, and then the test piece was kept at room temperature (normal temperature test). After leaving the test piece in a constant temperature room at 80°C for 5 minutes, the adhesive strength was measured at that temperature (heat resistance test) under the same conditions as above ◎ The results are shown in Table 4 〇 Example 2 Copolymer ■ Using a ゛r die film molding machine (extruder 65 order σ, T die effective width 800 m), the resin temperature was 22.
It was molded into a film with a thickness of 60 μm at 0° C. and a molding speed of 30 m/min. Dibutyltin dilaurate was applied as a 0, 1-, dfl:% ethyl alcohol solution to both surfaces of this film using a roll coating method, and then dried with a hot air dryer at 60°C to form a film-like crosslinkable adhesive. did.

The results of the adhesive strength test conducted in the same manner as in Example 1 are shown in Tables 3 and 4.

Example 3 Copolymer 182% by weight, dibutyltin dilaurate masterbatch 5% by weight used in Example 1, incyanate compound (manufactured by Nippon Polyurethane Co., Ltd., Millionate MR73)
% by weight and calcium carbonate (average particle size 2μ) 10wt.
% in a Henschel mixer, and this mixture was mixed with 50%
Using a blown film molding machine (die diameter 150m+n&5) with a mm9 extruder, the resin temperature was 150°C.
A crosslinkable adhesive in the form of a paper film was obtained by molding into a tubular film with a thickness of 60 μm at a molding speed of 15 m/min, and cutting this tube open to obtain a flat film.

The results of the adhesive strength test conducted in the same manner as in Example 1 are shown in Tables 3 and 4.

Example 4 In Example 2, 10% by weight of an incyanate compound (manufactured by Nippon Polyurethane Co., Ltd., Millionate MR) was added to the formed film instead of the solution of diptyl anchor dilaurate.
A film-like crosslinkable adhesive was obtained in the same manner as in Example 2, except that an ethyl acetate solution was used.

The results of the adhesive strength test conducted in the same manner as in Example 1 are shown in Tables 3 and 4.

Example 5 The procedure of Example 1 was repeated except that copolymer (2) was used instead of copolymer (2).

Example 6 In Example 2, the procedure was the same as in Example 2 except that copolymer (2) was used instead of copolymer (2).Example 7 In Example 4, copolymer (2) was used instead of copolymer (2). Comparative Example 1 The procedure was the same as in Example 4, except that copolymer (1) was used. Comparative Example 1

Comparative Example 2 Same as Example 1 except that copolymer ■ was used instead of copolymer ■ Comparative Example 3 In Example 1, copolymer ■ was used instead of copolymer ■. The procedure was the same as in Example 1, except that copolymer (■) was used.゛(The following is a blank space) Table 3 *Peeling during hot water V immersion Table 4 -40'

Claims (1)

[Claims] A copolymer of ethylene, an ethylenically unsaturated silane compound, an unsaturated glycidyl compound, and another ethylenically unsaturated compound, the unit being an ethylenically unsaturated silane compound, an unsaturated glycidyl compound, and another ethylenically unsaturated compound. The content of each is based on the copolymer weight, 0.
01-5% by weight, 0.1-20% by weight, f1'% and 5-
40% by weight of a copolymer as a main component.