JPS6048554B2 - Adhesive composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an adhesive composition, and more particularly to an adhesive composition with excellent heat resistance.

As reactive adhesives currently produced industrially, those containing reactive components such as epoxy resins, urethane resins, unsaturated polyesters, and cyanoacrylates are well known. It takes a high temperature or a long curing time to reach this point, and there is still room for improvement in terms of adhesive strength for those with a fast curing rate, so the curing rate and adhesive strength are not well balanced.

On the other hand, acrylic adhesives are known in which acrylic monomers such as alkyl acrylates or methacrylic monomers such as alkyl methacrylates are used as reactive components, and synthetic rubber is blended to impart toughness. has a fast curing speed and relatively good adhesive strength.

However, even with this acrylic adhesive, the adhesive strength decreases significantly at high temperatures, and therefore the range of application is limited. The present invention solves these problems and provides an acrylic adhesive composition that cures quickly and has excellent adhesive strength, particularly at high temperatures.

That is, the present invention provides (a) ester compounds of acrylic acid or methacrylic acid of tris(hydroxyalkyl)isocyanurate 5 to
(b) At least one polymerizable monomer selected from the group consisting of acrylic monomers other than (a) and methacrylic monomers (c) Synthetic rubber 5 to 6% by weight so that the total amount is 100% by weight.

The above component (a) is an ester compound obtained by esterifying all or part of the hydroxyl group of tris(hydroxyalkyl)isocyanurate with acrylic acid or methacrylic acid, and is an ester compound obtained by esterifying all or a part of the hydroxyl group of tris(hydroxyalkyl)isocyanurate with acrylic acid or methacrylic acid. It can be easily synthesized by carrying out an esterification reaction with methacrylic acid using a conventional method.

Examples of tris(hydroxyalkyl)isocyanurate include tris(2-hydroxyethyl)isocyanurate, tris(2-hydroxypropyl)isocyanurate, tris(3-hydroxypropyl)isocyanurate, among others, tris(2-hydroxypropyl)isocyanurate, etc. -hydroxyethyl) isocyanurate is advantageously used.

Tris(hydroxyalkyl)isocyanurate is 1
It has three hydroxyl groups in the molecule, but one or more of these hydroxyl groups must be esterified with acrylic acid or methacrylic acid, and in particular, 1.8 or more on average must be esterified with acrylic acid or methacrylic acid. It is preferable to use a compound that has a compound of 1 to 3 or 3, as it has a remarkable effect on increasing the cohesive force of the adhesive at high temperatures. The amount of the acrylic acid or methacrylic ester of tris(hydroxyalkyl)isocyanurate used is 5 to 50% by weight based on the total amount of components (a), (b) and (c). If it is less than 5% by weight, the effect of improving adhesive strength at high temperatures will not be sufficient.

Moreover, if the amount exceeds 50% by weight, the curing shrinkage of the adhesive composition increases, and the interface with the adherend is more likely to break. The acrylic monomers and methacrylic monomers contained in component (b) above include methyl acrylate, ethyl acrylate, butyl acrylate, 3-hexyl acrylate, 2-ethylhexyl acrylate, lauryl acrylate, and acrylic acid. Acrylic acid alkyl esters such as acrylic acid alkyl esters such as cyclohexyl, similar methacrylic acid alkyl esters, diacrylic esters of dihydric alcohols such as ethylene glycol, propylene glycol, butylene glycol, hexanediol, similar dimethacrylic acids esters, triacrylic esters of trihydric alcohols such as glycerin and trimethylolpropane, similar trimethacrylic esters, tetraacrylic esters of tetrahydric alcohols such as pentaerythritol, similar tetramethacrylic esters, acrylic acid, methacrylate acids, other derivatives of acrylic acid or methacrylic acid containing carboxyl groups, hydroxyalkyl acrylates such as hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxybutyl acrylate, similar hydroxyalkylmethacrylates,
Derivatives of acrylic acid or methacrylic acid having hydroxyl groups, such as partial esters of polyalcohols obtained by esterifying a portion of the hydroxyl groups of polyalcohols such as glycerin, trimethylolpropane, and pentaerythritol with acrylic acid or methacrylic acid; acrylics; Examples include derivatives of acrylic acid or methacrylic acid having an oxirane group, such as acid glycidyl ester and glycidyl ester methacrylate.

Among these, methyl acrylate,
Ethyl acrylate, methyl methacrylate, ethyl methacrylate, ethylene glycol dimethacrylate or butylene glycol dimethacrylate (b
) It is preferable to use 5% or more of the ingredients.

In addition, when an acrylic acid alkyl ester or a methacrylic acid alkyl ester is used in combination with an acrylic acid or methacrylic acid derivative having a COOH group, 0H group, oxirane group, etc., it is possible to achieve a balance between adhesion to the adherend and adhesive strength. It is advantageous to make a good adhesive.

Other polymerizable derivatives of acrylic acid or methacrylic acid can also be used, but they are used as appropriate, taking into consideration the properties, pot life, etc. of the adhesive composition.

The acrylic monomers or methacrylic monomers selected from one or more of the above groups include the above (a), (b) and (c).
) is used in an amount of 10 to 9% based on the total amount of components.

If the amount used is less than % by weight, the adhesive composition will have high viscosity and workability will deteriorate. Moreover, when the amount exceeds 9%, the adhesive strength of the adhesive composition decreases. In addition, polymerizable monomers other than acrylic monomers and methacrylic monomers, such as styrene, divinylbenzene, vinyl acetate, etc., can also be used together, but from the viewpoint of adhesive strength and reactivity, they should not be used in large quantities. It is not recommended to use it, and the above (a) and (b)
It is preferable to use m% by weight or less based on the total amount of components () and (c).

The synthetic rubber of component (c) above includes butadiene rubber,
Styrene-butadiene rubber, isobutene-isoprene rubber, chloroprene rubber, chlorosulfonated polyethylene rubber, butadiene-acrylonitrile rubber, urethane rubber, acrylic rubber, epi. Chlorhydrin rubber, isoprene rubber, etc. can be used, and those that form a homogeneous solution with other components as adhesive compositions are particularly preferred.

The scope of use of synthetic combs is (a), (b) and (c) above.
The amount is 5 to 6% based on the total amount of ingredients.

If it is less than 5% by weight, the adhesive strength will not be sufficient, and if it exceeds 6% by weight, the adhesive composition will become highly viscous and lack fluidity, which is not preferable.

The above components (a), (b) and (c) are used in an amount of 100% by weight.

The adhesive composition according to the present invention is cured by adding a radical catalyst, and the radical catalyst may be blended in advance or added immediately before use.

As such a radical polymerization catalyst, hydroperoxide, dialkyl peroxide, diacyl peroxide, peroxy ester, ketone peroxide, etc. can be used. Specifically, cumene hydroperoxide, t-butyl hydroperoxide, peroxide, etc. Menthane hydroperoxide, methyl ethyl ketone peroxide, cyclohexanone peroxide, dicumyl peroxide, t-butyl peroxybenzoate,
These include compounds such as t-butyl peroxyacetate, benzoyl peroxide and octanoyl peroxide.

These catalysts are blended in an amount of 0.1 to 5% by weight based on the total amount of components (a), (b) and (c).

If the amount used is less than 0.1% by weight, it will take a long time to cure the adhesive, and if it exceeds 5% by weight, the adhesive strength of the adhesive will decrease. ιThe adhesive composition of the present invention may contain fillers such as CacO3, talc, kaolin, S
iO. Thixotropic agents such as hydroquinone, hydroquinone monomethyl ether, methyl hydroquinone, t-butyl hydroquinone, phenothiazine, stabilizers such as oxalic acid, other antioxidants, pigments, dyes, ultraviolet absorbers, etc. can be blended. The adhesive composition of the present invention exhibits its adhesive function in a wide temperature range from room temperature to high temperature. By appropriately selecting a radical polymerization catalyst, the composition can be cured in several minutes to several hours at a temperature of 60° C. or higher, for example, to achieve the purpose of adhesion. In addition, for bonding at room temperature, it is preferable to use a radical polymerization catalyst and a polymerization promoter that can constitute a redox catalyst, and depending on the type, amount used, and means of combination, it can take several minutes to several hours. You can freely control the adhesion time.

To use a polymerization accelerator in combination, prepare a solution of the polymerization accelerator in a volatile solvent and apply it to one side of one adherend, then apply it to one side of the other adherend, and then apply it to one side of the other adherend. A method of applying an adhesive composition containing a radical polymerization catalyst to one side of the adherend material and overlapping the two sides, and a method of applying a composition containing a polymerization accelerator to the adhesive composition on one side. A method of applying an adhesive composition containing a radical polymerization catalyst to one side of a material, applying an adhesive composition containing a radical polymerization catalyst to one side of the other adherend, and then overlapping the two surfaces, and an adhesive composition containing a radical polymerization catalyst. There is a method in which a small amount of a polymerization accelerator is added and mixed into the material and applied to the adherend before polymerization and curing starts.

Many accelerators are known to date, such as fluoride, cobalt naphthenate, metal fields of acetylsetone, ascorbic acid, thiourea derivatives, amine compounds, and aldehyde-amine condensates. can also be used.

As a volatile solvent for the polymerization accelerator, hydrocarbons such as toluene, xylene, trichloroethylene, cyclohexane, ethylbenzene, and cumene, ethyl acetate, butyl acetate,
Examples include esters such as propyl acetate, ether compounds such as tetrahydrofuran, dioxane, and n-propyl ether, alcohols such as methanol and ethanol, and ketone compounds such as acetone and methyl ethyl ketone. Further, the adhesive composition may be diluted with these volatile solvents for the purpose of homogenizing the composition, reducing viscosity, improving wettability to adhesives, etc. The adhesive composition according to the present invention can be used as an adhesive that exhibits excellent adhesive strength in a short curing time on adherends made of a wide range of materials such as metal, plastic, wood, ceramics, and glass. In particular, the adhesive strength at high temperatures, particularly the tensile shear strength, is significantly superior to conventional acrylic reactive adhesives. Next, examples of the present invention will be shown.

Examples 1 to 5 15 parts by weight of butadiene-acrylonitrile rubber (Nippon Zeon (trade name: Nipole 1432J) was dissolved in 20 to 3 parts by weight of methyl methacrylate, and a predetermined amount of Tris (
2-hydroxyethyl)isocyanurate triacrylic ester dissolved in methacrylic acid and the remaining methyl methacrylate to prepare an adhesive composition;
An adhesive composition was prepared by adding 2 parts by weight of cumene hydroperoxide to make a homogeneous solution.

Table 1 shows the formulation of each adhesive composition. JISK-68
A steel test piece was polished, rubbed, and degreased in accordance with 48, and one side of each test piece was coated with 0.0.0% of an adhesive composition.
5g1 (11 coating amount) was applied to one side of another test piece, and a butyraldehyde-aniline condensate (Shinko Ouchi (Kiku brand name, Notsu Cellar 8) was applied as a polymerization accelerator to the adhesive composition Cumene Hydro. Apply the peroxide in an amount of about 1% by volume, adhere and fix both sides, and cure for 24R at room temperature. Measure the tensile shear strength at 25°C for 1.
The experiments were carried out at 00°C and 127°C.

The tensile shear strength was measured in accordance with JISK-6850. In addition, the measurement was carried out after leaving the test piece at the specified temperature for 3 hours.
It was used for measurement as it was. The measurement results are summarized in Table 1. Comparative Examples 1-3 Adhesive compositions were prepared in the same manner as in Examples 1-5 except that ethylene glycol dimethacrylate and trimethylolpropane triacrylate were used instead of tris(2-hydroxyethyl)isocyanurate triacrylate. After adjusting the material, a steel test piece was attached and the tensile shear strength was measured.

The formulation and measurement results of tensile shear strength are summarized in Table 1. Examples 6-8 Chlorosulfonated polyethylene (Showa Neoprene Co., Ltd.)
Three parts (trade name, Hypalon 30) were dissolved in 15 parts of methyl methacrylate.

To this, a predetermined amount of tris(2-hydroxyethyl)isocyanurate dissolved in 1 part of methacrylic acid and the remaining methyl methacrylate was added to prepare an adhesive composition, and 2 parts by weight of cumene hydroperoxide was added. An adhesive composition was prepared by adding and mixing to obtain a uniform solution. The formulations of each adhesive composition are summarized in Table 2. In the same manner as described in Examples 1 to 5, a steel test piece coated with a butyraldehyde-aniline condensate (Nockseller 8) and a copper test piece coated with an adhesive composition were adhesively fixed and kept at room temperature. After curing for 2 $f, the tensile shear strength at 25°C, 100°C and 127°C was determined by J'I. The measurement results are shown in Table 2. Comparative Example 4 Chlorosulfonated polyethylene (Hyparonto 0) 36
A composition was prepared from 54 parts by weight of methyl methacrylate, 1 part by weight of methacrylic acid, and 2 parts by weight of cumene hydroperoxinide, and a steel test piece was adhered in the same manner as in Examples 6 to 8. The tensile shear strength was measured at , 100°C, and 127°C.

The seven measurement results are shown in Table 2. As is clear from the above Examples and Comparative Examples, tris(hydroxyalkyl)isocyanurate. Compared to the adhesive composition of the present invention, even when other polyfunctional acrylic or methacrylic monomers such as trimethylolpropane triacrylate and ethylene glycol dimethacrylate are used instead of acrylic acid or methacrylic ester, , only those with much lower adhesive strength at high temperatures can be obtained.

This is thought to be because the acrylic acid or methacrylic ester of tris(hydroxyalkyl)isocyanurate not only functions as a mere crosslinking component, but also because its skeletal structure itself has excellent heat-resistant cohesive strength.

The adhesive composition according to the present invention exhibits adhesive strength sufficient to be used as a structural adhesive after curing at low temperatures and for a short time.
In particular, it has excellent tensile shear strength at high temperatures. Tris(2-hydroxyethyl)isocyanurate triacrylate used in Examples 1 to 5 was obtained by the following production example.

Production example tris(2-hydroxyethyl)isocyanurate 26
1 da, acrylic acid 238 da, balatoluenesulfonic acid 2
69, phenothiazine 0.129, toluene 600y, equipped with a stirrer, thermometer, water separator, air introduction tube,
The mixture was placed in a flask, and while a small amount of air was blown in, the reaction was carried out under heating and reflux while separating the produced water from the system.

Claims (1)

[Claims] 1(a) Tris(hydroxyalkyl)isocyanurate ester compound of acrylic acid or methacrylic acid 5
-50% by weight (b) 10-90% by weight of at least one polymerizable monomer selected from the group consisting of acrylic monomers and methacrylic monomers other than (a) and (c) synthetic rubber 5 An adhesive composition comprising 100% by weight of 60% by weight.