JPH09111193A - Bonding method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a high bonding strength by using a curable primer and a curable pressure-sensitive adhesive cast tape or sheet. SOLUTION: A primer layer containing an ethylenically unsaturated compound and a decomposition accelerator for a polymerization initiator is provided on the surface of a first adherend, and a second adherend is then bonded thereto through a cast tape consisting of an ethylenically unsaturated compound, a pressure-sensitive adhesive acrylic polymer and a polymerization initiator.

Description

Detailed Description of the Invention

TECHNICAL FIELD The present invention has a property as a pressure-sensitive adhesive that exhibits tackiness at the time of bonding and easily adheres to various adherends, and after bonding, it cures at room temperature in a short time. The present invention relates to a bonding method showing a strong and strong adhesive force.

[0001]

2. Description of the Related Art A curable pressure-sensitive adhesive tape (or sheet) which has tackiness at the time of joining, can be easily temporarily adhered to an adherend, and gradually hardens after being adhered to show a strong adhesive force,
Moisture-curing type which is cured by moisture in the air or moisture of adherend (Japanese Patent Publication No. 47-44017, Japanese Patent Publication No. 49-5895, Japanese Patent Publication No. 54-64536, Japanese Patent Publication No. 58-1).
No. 71460, No. 59-58071, No. 61-145268, No. 61-1482.
No. 81), a thermosetting type that is cured by heat (Japanese Patent Publication No. 50-1).
2464, JP 51-6235, JP 54-102335, JP 55-8113, JP 59-14508, and JP 59-10.
8072, JP-A-60-217283, JP-A-61-81467), light-curable photo-curing type (JP-A-56-120786, JP-A-57-15).
9864, JP-A-60-69178, JP-A-61-162574), and an anaerobic curing type that cures by blocking air (JP-B-58-12918, JP-A-59-199784). Gazette, JP-A-59-
199785, JP-A-60-6773, JP-A-60-11568, and JP-A-60-13868.
Publication).

However, each curable pressure-sensitive adhesive tape (or sheet) has a serious problem. That is, the moisture curing type needs to be stored in a dry state until it is used, and requires special equipment for manufacturing. The thermosetting type cannot be applied to heat-sensitive materials, and the photocuring type can be used only with a tape using a transparent film that transmits light. The anaerobic curable type requires a storage state in which it is always in contact with air, and if the curability is to be improved, it is difficult to keep the balance between the curability and the preservability such that the preservability is inferior.

Originally, the most ideal curable pressure-sensitive adhesive tape (or sheet) is one which is cured and adhered only by being attached without applying any energy. The above-mentioned moisture-curing type and anaerobic-curing type correspond to this, but it is very difficult to express such a function with ordinary adhesive tape in terms of storability, and even if it is possible, it is a halfway balance with curability. I can only do something.

In order to solve such a problem, a curable pressure-sensitive adhesive tape of a type in which two tapes are attached at the time of use and the reactive components are contained in separate tapes (JP-A-58).
No. 67777) is proposed. However, the design of the resin structure is very important in order to react easily at room temperature and to exert a strong adhesive strength, and conventional curable pressure-sensitive adhesive resins exhibit satisfactory performance. You cannot do it. The problem with the above-mentioned double-bonding type curable pressure-sensitive adhesive tape (or sheet) using a conventional resin is that the adhesive property at the time of bonding and the adhesive property after bonding and curing are unbalanced, and in most cases the adhesive property is If the characteristics were good, the adhesive strength was poor, and if the adhesive strength was high, the initial tackiness was poor. Therefore, even if the composition with the tape is a double-bonded type and the storage stability and curability are both achieved, a curable adhesive tape with an excellent balance of adhesive properties and adhesive properties can be obtained without proper resin design. I couldn't do it.

[0005]

DISCLOSURE OF THE INVENTION The present invention is a conventional two-sided bonding type curable adhesive tape produced without considering the structure and molecular weight of the resin, which has a poor balance between the adhesive property and the adhesive force after curing. By designing a resin that eliminates the above defects and fully considers the balance between the two, by using a curable primer and cast tape, the preservability is good and the adhesive properties before curing and the adhesive strength after curing are improved. (EN) A method for adhering a curable pressure-sensitive adhesive tape that is sufficiently excellent and that is cured at room temperature in a short time.

[0006]

According to the present invention, a primer layer containing an ethylenically unsaturated group-containing compound (A) and a polymerization initiator decomposition accelerator (B) is provided on the surface of a first adherend. After that, the second adherend is adhered via a curable pressure-sensitive adhesive cast tape comprising the ethylenically unsaturated group-containing compound (A), the pressure-sensitive adhesive acrylic polymer (C) and the polymerization initiator (D). This is a bonding method.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, the ethylenically unsaturated group-containing compound (A) used in the primer and the cast tape is diethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, tetraethylene glycol dimethacrylate. Poly (meth) acrylate or mono (of polyhydric alcohols such as methacrylate, polyethylene glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate (Meth) acrylate and the like, and the number average molecular weight of the oligomer is 400
Up to 10,000, preferably up to 5,000 polyester, polyether, polyurethane, epoxy oligomer, polysulfide, polycaprolactone,
Examples include poly (meth) acrylates such as polycarbonate and mono (meth) acrylates. In particular, unsaturated polyester oligomers obtained by ring-opening polymerization of a compound having a hydroxyl group, a cyclic acid anhydride, and an epoxide having an ethylenically unsaturated group, the production method of which is described in JP-A No. 61-126128. Is suitable as the ethylenically unsaturated group-containing compound (A).

As the compound having a hydroxyl group used in the synthesis of the unsaturated polyester oligomer, general alcohols such as methyl alcohol, ethyl alcohol, propyl alcohol and isopropyl alcohol, and ethylene glycol, propylene glycol, 1,4-
Butylene glycol, 1,3-butylene glycol, butenediol, hexanediol, cyclohexanediol, bisphenol A, bisphenol F, diethylene glycol, dipropylene glycol and other low molecular weight diols, polyethylene glycol, polypropylene glycol, polypropylene-polyethylene glycol, polybutylene glycol , High molecular weight diols such as polyether diol and polyester diol. Trivalent or higher alcohol compounds such as glycerin, trimethylolpropane, 1,2,6-hexanetriol can be used, but diols are preferable. Examples of cyclic acid anhydrides include maleic anhydride, phthalic anhydride, and anhydrous 1,2-
Examples thereof include cyclohexanedicarboxylic acid, cis-4-cyclohexene-1,2-dicarboxylic acid anhydride, itaconic anhydride, glutaric anhydride, citraconic anhydride, and succinic anhydride. Examples of the epoxide having an ethylenically unsaturated group include glycidyl acrylate and glycidyl methacrylate. The synthesis is carried out by using 1 mol of a cyclic acid anhydride, 1 mol of an epoxide having an ethylenically unsaturated group, 0.1 to 1.0 mol of an organic compound having a hydroxyl group, and 0.1 to 1.0 mol of a radical polymerization inhibitor with respect to the epoxide. 4 phr, preferably 0.1 to 1 phr is put in a reaction vessel, and the temperature can be controlled with a uniform temperature distribution in a heater at 60 to 95 ° C., preferably 80 to
The mixture is stirred while being heated to 90 ° C., and further reacted under the condition that the oxygen concentration in the atmosphere in the reaction vessel is 1% to 10%, preferably 1 to 5%.

In the present invention, as the decomposition accelerator (B) of the polymerization initiator constituting the primer, N, N-dimethylbenzylamine, triethylamine, tributylamine, N, N-diethylaniline, N, N-dimethylaniline is used. , Tertiary amines such as N-phenyldiethanolamine, N-phenyldiisopropanolamine, dimethyl-p-toluidine, triethanolamine and 4-phenylmorpholine, lithium, calcium, strontium, barium, cerium, zirconium, vanadium, molybdenum, Manganese, iron, cobalt, nickel,
Chelates such as fatty acid salts such as lauryl acid salts, naphthenic acid salts, octylic acid salts, oleic acid salts and octenoic acid salts of metals such as copper, zinc, tin and lead, resin acid salts such as rosin salts and acetylacetonate complex salts. One or more metal compounds selected from compounds and the like can be used as the promoter. In particular, when an organic peroxide is used as the polymerization initiator (E), a decomposition accelerator (B) for the polymerization initiator
As either a tertiary amine or a metal compound,
Alternatively, it is preferable to use both of them in combination. Of these accelerators, the tertiary amine is usually used in a proportion of 1 to 100 parts by weight with respect to 100 parts by weight of the organic peroxide, and the metal compound is used in an amount of 0.01 to 10 with respect to 100 parts by weight of the organic peroxide. Used in proportions by weight.

In the present invention, the solvent for applying the primer may be a solvent usually called an organic solvent such as methyl ethyl ketone, methyl isobutyl ketone, toluene, cellosolve, ethyl acetate and butyl acetate. Any compound can be used as long as it can dissolve the saturated group-containing compound and the decomposition accelerator of the polymerization initiator, and may be a single solvent or a mixture of a plurality of solvents. The amount of solvent blended is
It may be appropriately determined depending on the method of applying the primer.

In the present invention, the tacky acrylic polymer (C) has a functional group such as a hydroxyl group, a tertiary amino group, a carboxyl group, an amide group, an N-substituted amide group and a nitrile group, and is generally an adhesive agent. It is used as an acrylic resin for automobiles. Further, even if the polymer alone is poor in tackiness, a polymer showing good tackiness properties by adding the ethylenically unsaturated group-containing compound (A) and other resins is a polymer (D) of the present invention. Can be used. The acrylic polymer having these functional groups includes one or several kinds of monomers having a hydroxyl group, a tertiary amino group, a carboxyl group, an amide group, an N-substituted amide group, a nitrile group, an alkyl (meth) acrylate, Vinyl acetate, vinyl propionate,
Examples thereof include copolymers with monomers such as vinyl ether and styrene.

Examples of the monomer having a hydroxyl group include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate and N-methylolacrylamide. Examples of the monomer having a tertiary amino group include dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, and dimethylaminopropyl (meth) acrylamide. Examples of the monomer having a carboxyl group include acrylic acid, methacrylic acid, crotonic acid, maleic acid, fumaric acid, itaconic acid and citraconic acid. Examples of the monomer having an amide group or an N-substituted amide group include acrylamide, methacrylamide, N-methyl (meth) acrylamide, N-ethyl (meth) acrylamide, N-methoxymethyl (meth) acrylamide,
Examples include N-ethoxymethyl (meth) acrylamide, N-propoxymethyl (meth) acrylamide, N-butoxymethyl (meth) acrylamide, N-tert-butylacrylamide, N-octylacrylamide, diacetone acrylamide. Examples of the monomer having a nitrile group include acrylonitrile, methacrylonitrile, crotononitrile, and fumaronitrile. Further, as the alkyl (meth) acrylate, methyl (meth) acrylate, ethyl (meth) acrylate,
There are alkyl (meth) acrylates such as butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate and octyl (meth) acrylate. In addition, cyclohexyl (meth) acrylate, benzyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, etc. and alkyl (meth) acrylates in which the alkyl group is substituted with an aromatic ring group, a heterocyclic group, a halogen atom, etc. are generally used. The monomers used in the synthesis of acrylic polymers can also be used in the synthesis of the polymers of the invention.

The reaction is an ordinary radical polymerization, and there is no limitation on the reaction method, and it can be carried out by a known polymerization method such as solution polymerization, bulk polymerization and emulsion polymerization, but it is easy to control the reaction. Solution polymerization is preferred because it can be directly transferred to the next operation. The solvent may be any solvent, such as methyl ethyl ketone, methyl isobutyl ketone, toluene, cellosolve, ethyl acetate, and butyl acetate, as long as it dissolves the resin of the present invention. A single solvent or a mixture of a plurality of solvents may be used. Further, the polymerization initiator used in the polymerization reaction is also known such as benzoyl peroxide, acetyl peroxide, methyl ethyl ketone peroxide, organic peroxides such as lauroyl peroxide, and azo initiators such as azobisisobutyronitrile. Anything can be used, and there is no particular limitation.

As the polymerization initiator (D), di-tert
-Butyl peroxide, tert-butyl cumyl peroxide, dicumyl peroxide and other dialkyl peroxides, acetyl peroxide, lauroyl peroxide, benzoyl peroxide and other diacyl peroxides, methyl ethyl ketone peroxide, cyclohexanone peroxide, 3 3, 5
-Ketone peroxides such as trimethylcyclohexanone peroxide and methylcyclohexanone peroxide, peroxyketals such as 1,1-bis (tert-butylperoxy) cyclohexane, ter
t-butyl hydroperoxide, cumene hydroperoxide, 1,1,3,3-tetramethylbutyl hydroperoxide, p-menthane hydroperoxide,
Diisopropylbenzene hydroperoxide 2,5
-Dimethylhexane-2,5-hydroperoxides such as dihydroperoxide, tert-butylperoxyacetate, tert-butylperoxy-2-
There is no particular limitation as long as it is a known one such as organic peroxides such as peroxyesters such as ethylhexanoate and tert-butylperoxybenzoate. The polymerization initiator (D) is generally used in an amount of 0.1 to 15 parts by weight, preferably 0.5 to 5 parts by weight, based on 100 parts by weight of the pressure-sensitive adhesive composition of the present invention.

A primer can be obtained by mixing and stirring the ethylenically unsaturated group-containing compound (A) obtained by each reaction, the decomposition accelerator (B) of the polymerization initiator and the solvent. Further, the ethylenically unsaturated group-containing compound (A), the tacky acrylic polymer (C) and the polymerization initiator (D) are mixed and stirred, and the solvent is placed in an oven by coating on release-treated paper or film. It can be volatilized to obtain a curable adhesive cast tape. It is sufficient to stir the respective mixtures at room temperature until they are apparently homogeneous.

In the bonding method according to the present invention, when two adherends are joined together, one of the adherends is first coated with a primer with a brush or spray to a thickness of about 1 to 10 μm, and the volatile matter is air-dried. In this case, since the coating thickness is very thin, the solvent component evaporates within a few minutes even at room temperature. further,
A curable pressure sensitive adhesive cast tape is attached to the other adherend, and the pressure sensitive adhesive cast tape is adhered to the adherend coated with the curable primer. After joining, the curing reaction immediately proceeds to reach a predetermined adhesive strength within 1 hour even at room temperature. In addition, the form of the curable pressure-sensitive adhesive cast tape is a cast tape having a film thickness of about 10 to 50 μm, which is composed only of the curable resin composition, and can be sufficiently impregnated with the curable resin composition and is a decomposition accelerator for the polymerization initiator. Any double-sided type tape having a core material made of a material capable of diffusing as described above can be used in the bonding method of the present invention.

In the present invention, it is also possible to partially add a polyisocyanate to partially crosslink the tacky acrylic polymer in order to improve the tackiness property before curing, and particularly to enhance the cohesive strength. Examples of such polyisocyanates include tolylene diisocyanate, 4,4′-diphenylmethane diisocyanate, hexamethylene diisocyanate, m-xylene diisocyanate, p-xylene diisocyanate, 1,5-naphthalene diisocyanate, isophorone diisocyanate, lysine diisocyanate, hydrogenation 4, There are diisocyanates such as 4′-diphenylmethane diisocyanate and hydrogenated tolylene diisocyanate, or both ends isocyanate adducts of these with glycols or diamines, or a mixture thereof, and if necessary, triphenylmethane triisocyanate, polyisocyanate Tri- or higher functional polyisocyanates such as methylene polyphenyl isocyanate can also be used by mixing with diisocyanates. Wear.

In the curable resin composition of the present invention, pigments, dyes, inorganic fillers, organic solvents, silver powder, copper powder, nickel powder and other metal powders, carbon, etc. A tackifier such as black, graphite, xylene resin or rosin resin, and a silane coupling agent can be added.

[0019]

The present invention will be described below with reference to examples. In the examples, "part" means "part by weight" and "%" means "% by weight". Synthesis of polyester oligomer

Oligomer 1 Ethylene glycol 3.4 parts Hexahydrophthalic anhydride 50.3 parts Glycidyl methacrylate 46.3 parts N, N-Dimethylbenzylamine 0.9 parts Hydroquinone 0.2 parts Ethyl acetate 25.0 parts

The above compositions were mixed and reacted in an air atmosphere at 80 ° C. for 10 hours, and after cooling, ethyl acetate 1
25 parts were added to obtain a solution of polyester oligomer (solid content 40%).

Synthesis of acrylic polymer

Polymer 1 Butyl acrylate 92.0 parts Acrylamide 2.8 parts 2-Hydroxyethyl methacrylate 5.2 parts Azobisisobutyronitrile 0.2 parts Ethyl acetate 150.0 parts

To 125 parts of the mixture of each composition heated to 80 ° C., 125 parts of the mixture of the same composition was dropped, and after the addition was finished, the mixture was heated and refluxed for 12 hours and cooled to obtain a solution of acrylic polymer (solid). Min 40%).

[0025]

Example 1 A primer was obtained by thoroughly mixing 100 parts of a solution of oligomer 1 and 4.0 parts of diethanolaniline. 45.8 parts of the solution of the oligomer 1 and 54.2 parts of the solution of the polymer 1 were sufficiently mixed, and 1.0 part of benzoyl peroxide was uniformly mixed with 100 parts of this resin solution, and polyethylene treated with silicone was used. It was coated on a terephthalate film so that the thickness after drying was 30 μm, and dried at 60 ° C. for 3 minutes to obtain a curable pressure-sensitive adhesive sheet.

With respect to the obtained curable pressure-sensitive adhesive sheet, Table 1 shows the measurement results of the pressure-sensitive adhesive properties (peeling adhesive force, tack, holding force) before curing and the shear adhesive force after curing. For curing, a curable primer was applied onto the adherend with a brush so that the dry film thickness was about 5 μm, and then a curable pressure-sensitive adhesive sheet was attached to one of the adherends to bond them. After the bonded adherends were left at room temperature of 25 ° C. for 30 minutes, the following measurements were performed.

(1) Peeling adhesive strength before curing A polyethylene terephthalate sheet having a thickness of 50 μm was attached to the adhesive surface of the obtained curable adhesive sheet, and the width was 25 mm.
Then, the polyethylene terephthalate film was peeled off, and the resulting adhesive surface was attached to a stainless steel plate (SUS304) polished with # 280 sandpaper.
After leaving it for 0 minutes, under the condition of 25 ° C and relative humidity of 65%,
The 180-degree peeling adhesive force was measured at a peeling speed of 300 mm / min.

(2) Tack before curing The obtained curable pressure-sensitive adhesive sheet was set on a slope having an inclination angle of 30 degrees, and the running distance was 1 at 25 ° C. and 65% relative humidity.
At 0 cm, a stainless steel ball was rolled, and the number of the largest ball stopped within 10 cm of the adhesive surface was measured. The number of the ball is represented by 32 times as many as 31 kinds of "name of ball" from 1/16 to 1.

(3) Holding power before curing A polyethylene terephthalate sheet having a thickness of 50 μm was attached to the adhesive surface of the obtained curable adhesive sheet, and the width was 25 m.
m, length 100 mm, and then the polyethylene terephthalate film was peeled off, and a 25 mm wide and 25 mm wide portion of the resulting adhesive surface was sandpaper # 2.
Stainless steel plate polished by 80 (SUS304)
Then, the time (second) until the pressure-sensitive adhesive sheet dropped from the stainless steel plate was measured at 40 ° C. and a load of 1 kg.

(4) Shear adhesive strength after curing A primer is dried to a thickness of 5 μm on an area of 10 mm in length and 10 mm in width on one of two aluminum plates having a length of 50 mm, a width of 10 mm and a thickness of 0.5 mm. And then air-dry, then 10mm in length and 10mm in width on the other aluminum plate.
The curable pressure-sensitive adhesive sheet that was cut into is attached, and it is joined to the surface to which the primer has been previously applied, and after room temperature 25 ° C for 30 minutes,
The shear strength was measured at a pulling rate of 5 mm / min under the condition of 25 ° C. and 65% relative humidity.

[0031]

Example 2 To 100 parts of the composition used for the curable pressure-sensitive adhesive sheet of Example 1, 0.2 parts of tolylene diisocyanate was further added.
Then, a curable pressure-sensitive adhesive sheet was obtained in the same manner, and aged at 50 ° C. for 3 days. About the obtained adhesive sheet, Example 1
The adhesive properties before curing and the shear adhesion after curing were measured in the same manner as in. The composition of the primer is the same as in Example 1.
The results are shown in Table 1.

Table 1 ─────────────────────────── Before curing Before curing Before curing After curing Examples Peeling adhesive strength Tack holding strength Breaking adhesion Force (gf / 25mm) (No.) (sec) (Kgf / cm ² ) ─────────────────────────── 1 1560 11 2450 55.0 ─────────────────────────── 2 1440 5> 24 hours 32.2 ─────────────── ─────────────

[0033]

As shown in Table 1, the adhesion method of the present invention has a peel adhesion before curing of 1400 gf / 25 mm or more, a tack of 5 or more, and a holding power of 1000 seconds even without addition of polyisocyanate. That is all. Further at room temperature 30
It cures within minutes and its shear adhesion is also 30 Kgf / cm ²
As described above, both the adhesive property before curing and the adhesive force after curing are excellent. In addition, in the bonding method of the present invention, since it is stored in the form of a primer and a curable pressure-sensitive adhesive tape until the time of use, components that cause a curing reaction do not react in a non-contact manner until bonding. The problematic storability was significantly improved. Furthermore, by adding an appropriate amount of polyisocyanate, the cohesive force is improved, and the holding force is kept even after 24 hours without impairing the peeling adhesive force before tacking, tack, and shear adhesive force after curing. can do.

As described above, according to the present invention, it is highly adhesive at the time of joining and can be temporarily adhered to an adherend, mechanical temporary fixing is unnecessary, and it is cured at room temperature in a short time to show a strong adhesive force,
It has become possible to obtain an adhesive method that has an excellent balance between the adhesive properties before curing and the adhesive strength after curing and has excellent storage stability.

Claims (1)

[Claims] 1. After providing a primer layer containing a compound (A) containing an ethylenically unsaturated group and a promoter (B) for decomposing a polymerization initiator on the surface of a first adherend, it contains an ethylenically unsaturated group. A bonding method which comprises bonding a second adherend through a curable pressure-sensitive adhesive cast tape comprising a compound (A), a pressure-sensitive acrylic polymer (C) and a polymerization initiator (D).