JPH0745649B2 - Adhesive manufacturing method - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for producing an adhesive, and particularly has an excellent adhesive force to a relatively soft adherend such as paper, wood, cloth and resin. The present invention relates to a method for producing an adhesive that exhibits good water resistance and exhibits good water resistance after adhesion.

[Prior Art] It has been conventionally known to use a copolymer containing a maleic acid compound unit, for example, a copolymer obtained by neutralizing an isobutylene-maleic anhydride copolymer as an adhesive component ( JP-B-49-34181).

However, this conventionally known neutralized product of the copolymer has insufficient adhesive strength, and since it is completely neutralized, it easily dissolves in water and is easy to handle, but poor in water resistance. However, after the bonding operation, there is a drawback that the adhesive strength is lowered in a humid environment.

On the other hand, there is also known an adhesive intended to improve the adhesive strength by imidizing a copolymer of maleic anhydride and a compound having a terminal double bond (Japanese Patent Publication No. 55-1954). However, this adhesive has a drawback that the adhesive strength is low.

[Problems to be Solved by the Invention] The present invention comprises a polymer containing a maleic acid compound unit, has excellent adhesive strength to paper, wood, cloth, rubber, resin and the like, and produces an adhesive having good water resistance. It is intended to provide a method.

[Means for solving problems]

As a result of repeated research to develop an adhesive having excellent adhesive strength and exhibiting good water resistance after adhesion, α,
The inventors have found that this object can be achieved by imidizing a copolymer of β-unsaturated dicarboxylic acid anhydride and a specific monomer and performing a partial neutralization treatment, and completed the present invention.

That is, the present invention comprises an α, β-unsaturated dicarboxylic acid anhydride unit and a compound unit having a terminal active double bond, and the molar ratio of the former to the latter is 1: 0.9 to 1: 5. The polymer is subjected to imidization treatment and neutralization treatment, the imidization ratio is at least 40%, and the degree of neutralization is 0.05 or more, 0.
Provided is a method for producing an adhesive, which comprises producing a modified copolymer of less than 3.

The copolymer used in the method of the present invention is composed of an α, β-unsaturated dicarboxylic acid anhydride unit and a compound unit having a terminal active double bond. Thing is a general formula (In the formula, R ₁ and R ₂ are a hydrogen atom or an alkyl group), for example, maleic anhydride, α-
This includes methyl maleic anhydride, α, β-dimethyl maleic anhydride, α-ethyl maleic anhydride and the like.

The compound having a terminal active double bond, which is the other monomer to be copolymerized with the α, β-unsaturated dicarboxylic acid anhydride, has the general formula (Wherein R is a hydrogen atom or an alkyl group, R'is an alkyl group, an aryl group, an aralkyl group, a carboxyl group, an alkoxycarbonyl group, or a halogen atom), a typical one of which is styrene. Or a derivative thereof and acrylic acid or a derivative thereof.

Styrene or a derivative thereof is represented by the general formula (R ₃ in the formula is a hydrogen atom, a halogen atom, or an alkyl group), and this benzene nucleus may further have an inactive substituent bonded thereto. Examples of such compounds include styrene, α-methylstyrene, p-methylstyrene, m-isobutylstyrene, o-chlorostyrene, α-chlorostyrene, α-ethylstyrene and the like.

In addition, acrylic acid or its derivative has the general formula (In the formula, R ₄ is a hydrogen atom or an alkyl group, and R ₅ is a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group or an aralkyl group). Mention may be made of acids, methacrylic acid, α-ethylacrylic acid and their methyl, ethyl, propyl, butyl, cyclohexyl or benzyl esters and the like.

These compounds having an active terminal double bond may be used alone or in combination of two or more.

Therefore, as an example of the copolymer used in the method of the present invention, a styrene compound-maleic acid compound copolymer,
Acrylic acid compound-maleic acid compound copolymer Binary copolymer such as isobutylene-maleic acid copolymer, isobutylene-styrene compound-acrylic acid compound copolymer, isobutylene-acrylic acid compound-malein Terpolymer such as acid compound copolymer, styrene compound-acrylic acid compound-maleic acid compound copolymer and isobutylene-styrene compound-acrylic acid compound-maleic acid compound copolymer A certain quaternary copolymer etc. can be mentioned.

The α, β-unsaturated dicarboxylic anhydride unit and the compound unit having a terminal active double bond in these copolymers must be present in a molar ratio of 1: 0.9 to 1: 5. is there. Copolymers having more α, β-unsaturated dicarboxylic acid anhydride units than this are practically difficult to produce, and more than α, β-unsaturated dicarboxylic acid anhydride monomers Lesser copolymers have lower adhesion.

These copolymers may be in any form such as alternating copolymers, graft copolymers, random copolymers and block copolymers.

In the present invention, the viscosity average molecular weight is usually 500 ~ 40
Those in the range of 0,000, preferably 1,000 to 200,000 are used.

Such a copolymer can be produced, for example, as follows.

That is, the required monomers are charged into the reaction vessel at a predetermined ratio, and sufficient deaeration is usually performed under cooling. When isobutylene is used as the monomer, this degassing treatment is performed with another monomer except isobutylene, and isobutylene is added after this treatment. Then, the polymerization reaction is carried out while stirring. The reaction temperature at this time is 30 to 200 ° C, preferably 45 to 2
00 ° C., reaction pressure 0 to 50 kg / cm ² G, preferably 0 to 20 kg /
cm ² G, the reaction time is 0.5 to 20 hours, preferably 1 to 10 hours.

In this copolymerization reaction, if necessary, a solvent such as ethylbenzene, cumene, n-butylbenzene or a mixture thereof, acetonitrile, nitromethane, nitroethane, methyl ethyl ketone, acetone, N, N-dimethylformamide, dimethylsulfoxide, or a peroxide is used. Benzoyl, lauroyl peroxide, cumene hydroperoxide,
Polymerization initiators such as tertiary butyl hydroperoxide, dicumyl peroxide and asobisisobutyronitrile can be used. This polymerization initiator is usually 0.01 to 10 parts by weight, preferably, to 100 parts by weight of all monomers,
It is used in a proportion of 0.05 to 5 parts by weight. This polymerization initiator may be added as it is, or may be diluted with a solvent and added. The catalyst may be added in the required amount at the start of the polymerization, or may be added in several divided portions during the polymerization.

In the method of the present invention, the copolymer thus obtained is used as a raw material and subjected to imidization treatment and neutralization treatment. The order of the imidization treatment and the neutralization treatment can be arbitrarily selected.

This imidization treatment may be performed on the above-mentioned untreated or neutralized copolymer by using, for example, lower amines such as ammonia, methylamine, ethylamine, propylamine, isopropylamine and butylamine, aromatic amines such as aniline, methylaniline and toluidine. Alternatively, it is carried out by directly reacting an alicyclic amine such as cyclohexylamine to form an amide, followed by heat treatment for imidization. The reaction temperature at this time varies slightly depending on the amine used, but in the case of ammonia, it is 0 to 120 ° C., preferably 20 to 100 ° C., and the reaction time is 0.5 to 20 hours, preferably,
1 to 10 hours.

Further, the temperature of the heat treatment for forming the imide is 100 to 300.
C., preferably 150 to 200.degree.

An imide group is formed in the copolymer by such an imidization treatment, but at this time, all of the amide groups do not change to imide, and some of them do not change and remain in the copolymer molecule. A free carboxyl group remains.

At this time, the imidization ratio needs to be at least 40%. If the imidization ratio is smaller than this, an adhesive having high adhesive strength and water resistance cannot be obtained.

In order to preferably carry out the neutralization treatment in the method of the present invention,
The copolymer is first dispersed in a specific mixed solvent, specifically, a solvent obtained by mixing water and an organic solvent having a solubility coefficient of 9 or more, and then an alkali is added to neutralize and dissolve the copolymer to form a solution. To prepare. Here, the solubility coefficient (δ) is a characteristic value of the liquid that is a measure of the mixing property between the liquids, and is given by the following equation when the molecular cohesive energy of the liquid is E and the molecular volume is V.

Solubility coefficient (δ) = (E / V) ^1/2 As the organic solvent having a solubility coefficient of 9 or more, for example,
Examples thereof include ethyl acetate, methylcyclohexanone, methylethylketone, furan, methyl acetate, acetone, cyclohexanone, cyclopentanone, ethylene glycol monoethyl ether, dimethylformamide, dimethyl sulfoxide, nitroethane, nitromethane, acetonitrile and chloroacetonitrile.

The neutralization treatment in the present invention is carried out by reacting the imidized or untreated copolymer with an alkali such as sodium hydroxide, potassium hydroxide, sodium carbonate or sodium acetate.

This neutralization treatment needs to be performed on a part of the carboxyl groups present in the copolymer, and if all the carboxyl groups are completely neutralized, the water resistance will decrease after adhesion. The degree of neutralization needs to be performed until the degree of neutralization is in the range of 0.05 or more and less than 0.3, based on the carboxyl groups present in the copolymer. Outside this range, the adhesive strength and water resistance cannot be sufficiently improved. The degree of neutralization here is
It can be calculated by the following formula.

Particularly suitable among these organic solvents are those having a medium hydrogen bonding force, such as methyl ethyl ketone, acetone, acetonitrile and the like. In the neutralization treatment of the copolymer, a mixed solution of the above organic solvent and water is used. The mixing ratio of both is 1 to 150 parts by weight, preferably 5 to 100 parts by weight, per 100 parts by weight of water.

The copolymer is dispersed in this mixed solvent, and an alkaline substance is added and reacted. The neutralized product formed by this neutralization reaction dissolves in the mixed solvent, and finally becomes a uniform solution. Examples of the alkaline substance used for this neutralization include sodium hydroxide, potassium hydroxide, sodium carbonate, sodium acetate, ammonia, ammonium hydroxide, urea, thiourea, and various organic amines.

These alkaline substances are used in an amount sufficient to obtain the required degree of neutralization. This neutralization reaction is usually 20-15
Completed in 0.5-10 hours at a temperature of 0 ° C.

The modified copolymer thus obtained can be used alone as an adhesive, but it is preferable to further add an inorganic filler, an epoxy compound or a rubber latex before use.

The inorganic filler used at this time can be arbitrarily selected from those commonly used as an additive component of an adhesive such as a metal compound, carbon black or sulfur.
As such a metal compound, for example, copper, silver, magnesium, calcium, strontium, barium, zinc, cadmium, aluminum, titanium, zirconium, tin, bismuth, chromium, molybdenum, manganese,
Examples thereof include oxides such as iron, cobalt and nickel, hydroxides, carbonates and sulfates. These are used in a proportion of 5 to 1000 parts by weight, preferably 10 to 500 parts by weight, based on 100 parts by weight of the modified copolymer.

These fillers increase the adhesive force of the adhesive of the present invention by the physical attraction between the surface and the polar carboxyl group of the modified copolymer.

For this reason, the smaller the particle size of the inorganic filler, the better. Usually, the particle size of 50 μm or less is used.

Next, as the epoxy compound, a compound having two or more epoxy groups is particularly suitable, and the epoxy group serves to react with the polar group of the modified copolymer to form a crosslink. As such an epoxy compound, for example, glycerin diglycidyl ether, ethylene glycol diglycidyl ether, diglycidyl ether of glycol such as polyethylene glycol diglycidyl ether, and diglycidyl ether of a compound having a carboxyl group can be used. .

These epoxy compounds are used in an amount of 1 to 150 parts by weight, preferably 5 to 100 parts by weight, based on 100 parts by weight of the modified copolymer.

The latex that is optionally added to the adhesive obtained by the method of the present invention imparts tack to the modified copolymer, and the dispersoid in the latex may be rubbery or resinous.

Examples of rubber latex dispersoids include styrene-
Butadiene copolymer, styrene-isoprene copolymer,
Examples thereof include rubbery polymers such as polyurethane elastomer, polychloroprene, nitrile rubber, butadiene rubber, methyl methacrylate-butadiene copolymer and natural rubber.

Examples of the dispersoid of the resin latex include polyvinyl acetate, ethylene-vinyl acetate copolymer, polyacrylic acid ester, polymethacrylic acid ester and the like.

These latexes are a kind of colloid sol having a rubber or resin component as a dispersoid and mainly water as a dispersion medium, and are 5 to 500 parts by weight, preferably 10 to 300 parts by weight in terms of dispersoid with respect to 100 parts by weight of the modified copolymer. It is blended in a ratio of parts by weight.

The adhesive obtained by the method of the present invention, if desired, additional components that are commonly used in ordinary adhesives, for example, organic fillers such as starch, wheat flour, soybean glue, rubber powder, and wood flour, and polyvinyl alcohol, Water-soluble resins such as carboxymethyl cellulose, hydroxyethyl cellulose, polyethyleneimine, sodium polyacrylate and the like can be added.

〔The invention's effect〕

According to the present invention, a copolymer having a compound unit having a terminal active double bond is subjected to imidization treatment and neutralization treatment under limited conditions to produce a modified copolymer, thereby producing a 90 ° It is possible to obtain an adhesive having a large peeling strength, exhibiting a good adhesive force to a soft adherend such as paper, wood, cloth, rubber, resin and the like, and further significantly improving the water resistance of the adhered portion.

〔Example〕

 The present invention will be described in more detail with reference to Examples and Comparative Examples.

The 90 ° peel strength, normal state adhesive strength and water resistant adhesive strength in each example are measured by the following methods.

(1) 90 ° peeling strength An aqueous solution of nuclear adhesive is applied to a cotton cloth with a width of 25 mm (normal cotton canvas 1209) specified in JIS L3102 to a thickness of 200 μm and cured at 23 ° C for 7 days to prepare an adhesive test piece. did. Then, using this test piece, the tensile strength is 50 in accordance with JIS K 6854.
Measured at mm / min and a temperature of 23 ° C.

(2) Normal adhesive strength A high-viscosity solution (a total of three veneers: a 0.75 mm thick lauan veneer, a 1.5 mm thick lauan veneer and a 0.75 mm thick lauan veneer Adhesive) is applied to a thickness of 0.3 mm and joined sequentially to make plywood, which is pressed at 10 kg / cm ² for 10 minutes, and then at 120 ° C and 10 kg / cm ² for 30 minutes. And Using this test piece, its adhesive strength was measured according to JAS2.

(3) Water-resistant adhesive strength Using the above-mentioned test piece, in accordance with JAS2, in hot water at 70 ℃ 2
After soaking for an hour, the coating was dried at 60 ° C. for 3 hours, and the adhesive strength after that was measured.

Examples 1 to 6 When using isobutylene in an autoclave having an internal volume of 1, predetermined amounts of the components shown in Table 1 except isobutylene,
460 ml of acetonitrile as a solvent and 0.6 g of benzoyl peroxide as a polymerization initiator were charged, the mixture was cooled at -10 ° C, and the inside of the container was sufficiently degassed. Then, when using isobutylene, add a predetermined amount of isobutylene, 400 rpm
The copolymerization reaction was carried out at 110 ° C. for 2 hours while stirring.

After the reaction was completed, the obtained reaction mixture was put into water to precipitate the copolymer.

Then, this copolymer is crushed and ammonia gas is added to the first
After direct reaction under the conditions shown in the table, at a pressure of 10 mmHg,
An imide-treated modified copolymer was obtained by heat treatment under the conditions shown in Table 1.

Next, this imide-modified copolymer was dispersed in a mixed solvent of water: acetone at a weight ratio of 90:10, and neutralized with an aqueous solution of sodium hydroxide under the conditions shown in Table 1 to a predetermined degree of neutralization. Treatment gave the desired adhesive as a 15 wt% solution.
(However, in the comparative example, the solvent is water only) Comparative Examples 1 to 8 In the same manner as in Example 1, neutralization was performed without imidization treatment or with imidization treatment at an imidization ratio of less than 40%. The copolymers produced by carrying out the modification treatment were produced by using the feed rates of the raw materials shown in Table 1, respectively, and neutralized to a neutralization degree of 1 at a temperature of 90 ° C. for 6 hours. The wa-copolymer was tested.

The above results are shown in Table 1.

As is clear from this table, when only the neutralization treatment is performed without imidization, or even when the imidization rate is less than 40% when the neutralization treatment is performed ,
Low 90 ° peel strength, normal adhesive strength, and water resistant adhesive strength.

Examples 7 to 14 In the same manner as in Example 1, the copolymers obtained at the raw material ratios shown in Table 2 were subjected to the modification treatment shown in Table 2 and the inorganic fillers were added to the copolymers. The performance of the adhesive prepared by compounding the epoxy compound or latex was tested. The results are shown in Table 2.

Comparative Examples 9 to 12 An inorganic filler, an epoxy compound or a latex was added to a copolymer having an imidization ratio of less than 40% or a neutralization degree of 0.3 or more, which was modified under the conditions shown in Table 2 in the same manner as in Example 7. The performance of the compounded and manufactured adhesive was tested. The results are shown in Table 2.

As is clear from this table, when the imidization ratio of less than 40% is used, the normal state adhesive strength and the water resistance adhesive strength are lower than those of the adhesive according to the present invention, and the neutralization degree of 0.3 or more is used. When used, the 90 ° peel strength, normal adhesive strength, and water resistant adhesive strength are lower than those of the adhesive of the present invention.

Claims (1)

[Claims] 1. A copolymer comprising an α, β-unsaturated dicarboxylic acid anhydride unit and a compound unit having a terminal active double bond, wherein the molar ratio of the former to the latter is 1: 0.9 to 1: 5. Polymer, subjected to imidization treatment and neutralization treatment, the imidization ratio is at least 40%, and the degree of neutralization is 0.05 or more, the adhesive characterized by producing a modified copolymer less than 0.3 Production method.