JPH02685A - Adhesive composition - Google Patents

Abstract

PURPOSE:To obtain the above composition excellent in normal state adhesiveness, initial adhesiveness and storage stability by mixing an incompletely neutralized product of a specified copolymer with a latex and aluminum hydroxide. CONSTITUTION:An incompletely neutralized product (with W degree of neutralization of 0.05-0.5) of a copolymer of a viscosity-average MW of, desirably, 1000-200000, composed of at least one kind of monomer unit selected from among an isobutylene unit, a styrene monomer unit and an acrylic acid monomer unit and maleic acid monomer units, obtained by copolymerizing at least one monomer selected from among an isobutylene monomer, a styrene monomer and an acrylic acid monomer with a maleic acid monomer and neutralizing the copolymer, is mixed with a latex selected from a latex of a rubber and a latex of a resin, aluminum hydroxide of a mean particle diameter of, desirably, 0.01-100mum and, optionally, calcium carbonate of a mean particle diameter of, desirably, 0.01-50mum.

Description

Detailed Description of the Invention [Industrial Application Field 1] The present invention relates to a novel adhesive composition, particularly an adhesive composition suitable for bonding relatively soft materials such as wood, paper, and plastics. It is related to.

[Prior art] Until now, adhesives mainly made of latex include styrene-butadiene-based latex adhesives, acrylonitrile-butadiene-based latex adhesives, methyl methacrylate-butadiene-based latex adhesives, and polyisoprene-based latex adhesives. is known, and is also used as an adhesive for relatively soft materials such as wood, paper, cloth, and plastic. A mixture of aluminum and latex is also known (Japanese Unexamined Patent Publication No. 58-3
Publication No. 6030).

However, although such adhesives have an almost satisfactory level of adhesive strength under normal conditions, their initial adhesive strength is low, so it takes a long time to compress them in the bonding process, such as pressing, to obtain the required minimum adhesive strength. This method is time-consuming, and especially when adhesive pressing is performed continuously, the work cycle becomes long and manufacturing efficiency is reduced.

[Problems to be Solved by the Invention] The present invention overcomes these drawbacks of conventional adhesives, and exhibits not only excellent permanent adhesion but also excellent initial adhesion and, in some cases, even better adhesion. The object is to provide a novel adhesive composition that exhibits storage stability.

[Means for Solving the Problems] The present inventors have conducted intensive research to improve the adhesive strength of copolymers mainly composed of isobutylene, styrene monomers, or acrylic acid monomers, and maleic anhydride. When we used a completely neutralized isobutylene and maleic anhydride copolymer used in adhesives with a low degree of neutralization, it was surprisingly possible to improve not only the normal adhesion but also the initial adhesion. It has been found that good storage stability can be obtained by adding calcium carbonate and scales, and based on this knowledge, the present invention has been completed.

That is, the present invention provides: (A) at least one selected from isobutylene units, styrene monomer units, and acrylic acid monomer units;
An incompletely neutralized product of a copolymer composed of a seed monomer unit and a maleic acid monomer unit with a degree of neutralization of 0.05 to 0.5, (B) Latte Zx, and (C) The present invention provides an adhesive composition comprising aluminum hydroxide and optionally further (D) calcium carbonate.

In the present invention, it is necessary to use a neutralized product of a specific copolymer as one of the components, that is, component (A). It is obtained by copolymerizing at least one type of heptamer selected from acrylic acid monomers and a maleic acid monomer in a predetermined ratio, and such copolymers include, for example, isobutylene, Binary copolymer of styrene monomer or acrylic acid monomer and maleic acid monomer, terpolymer of styrene monomer, acrylic acid monomer and maleic acid monomer, styrene monomer, isobutylene and maleic acid ternary copolymers with acrylic acid monomers, isobutylene, and maleic acid monomers, and quaternary copolymers with histidine monomers, acrylic acid monomers, isobutylene, and maleic acid monomers. There is such a thing as merging.

Styrene monomers used in this case include styrene and σ-methylstyrene, acrylic acid monomers include acrylic acid, methacrylic acid, and their esters, and maleic acid monomers include:
Maleic acid and its anhydride.

The copolymer used in the present invention has a viscosity average molecular weight of 500 to 4.
00,000, preferably 1,000-200,000
It is suitable that the maleic acid monomer unit accounts for 5 to 70 mol%, preferably 10 to 60 mol%.

These copolymers can be produced, for example, as follows.

First, a predetermined amount of each 7-mer is placed in a reaction vessel and thoroughly degassed while cooling. In addition, when isobutylene is used as a structural unit at this time, a predetermined amount of each 7mer other than isobutylene is charged into a reaction vessel, and after cooling and sufficient degassing, a predetermined amount of isobutylene is added. The monomer mixture thus treated is then heated at 30-200°C.
The desired copolymer can be obtained by reacting with stirring, preferably at 45 to 180°C.

The polymerization time in this case is 0.5 to 20 hours, usually 1 to 1 hour.
The range is 0 hours.

In this copolymerization reaction, ethylbenzene, cumene, n-butylbenzene, acetonitrile,
Solvents such as nitromethane, nitroethane, methyl ethyl ketone, acetone, N,N'-dimethylformamide, dimethyl sulfoxide or mixtures thereof, benzoin peroxide, lauroyl peroxide, cumene hydroperoxide, tertiary butyl hydroperoxide, dicumyl peroxide, Catalysts such as azobisisobutyronitrile can be used.

In the present invention, the copolymer thus obtained is used after being neutralized with an alkali. Examples of the alkali used in this case include sodium hydroxide, potassium hydroxide, ammonium hydroxide, sodium carbonate, ammonia, sodium acetate, urea, thiourea, and organic amines.

This neutralization reaction occurs at a temperature of 20 to 150°C.
This can be done by treating for 5 to 10 hours.

In this neutralization treatment, the degree of neutralization of the copolymer is 0.05 to 0.
It is necessary to control the amount, concentration, temperature, time, etc. of alkali so that it falls within the range of 5.

In the present invention, the degree of neutralization is defined as the acid value of the copolymer before neutralization minus the acid value of the copolymer after neutralization, and then dividing this value by the acid value of copolymer before neutralization. This is what I did.

Rubber latex, such as styrene-butadiene copolymer, styrene-isoprene copolymer, polyurethane elastomer, polychloroprene, nitrile rubber, butadiene rubber, methyl methacrylate-butadiene copolymer, natural rubber, etc. as a rubber dispersoid, and resin. latex,
For example, there are resin dispersoids made of polyvinyl acetate, ethylene-vinyl acetate copolymer, polyacrylic ester, polymethacrylic ester, and the like.

These latexes are formed as a type of colloidal sol in which the above-mentioned rubber dispersoid or resin dispersoid is dispersed in water. This latex is a neutralized product of copolymer 10
0 parts by weight, 5 to 1,000 parts by weight in terms of dispersoids,
It is preferably used in an amount of 10 to 500 parts by weight.

In addition to Al1(OH)3, the aluminum hydroxide used as component (C) of the present invention includes hydrated aluminum oxide AQ20.・XH2O is also included.

There are no particular restrictions on these particles, but the average particle size is 0.0
Preferably, the thickness is 1 to 100 μm.

This aluminum hydroxide is a neutralized product of copolymer 100
5 to 1000 parts by weight, preferably 10 to 1000 parts by weight
It is blended in a proportion of 700 parts by weight.

The adhesive composition of the present invention may further contain calcium carbonate as the case may be, and as the carbonate, ground calcium carbonate, precipitated calcium carbonate, and chalk are used. Although there is no particular restriction on the size of the particles, it is usually preferable to have an average particle size of 0.01 to 50 μm.

This calcium carbonate is added in an amount of 5 to 1000 parts by weight, preferably 10 to 7 parts by weight, based on 100 parts by weight of the neutralized copolymer.
00 parts by weight.

The adhesive composition of the present invention may further contain various additives commonly used in latex-containing adhesives, if desired. Such additives include inorganic fillers, organic fillers, and water-soluble resins, and these inorganic fillers include compounds of divalent or higher-valent metals, carbon black, sulfur powder, and the like.

Examples of compounds of divalent or higher-valent metals include oxides of copper, magnesium, strontium, barium, zinc, cadmium, titanium, zirconium, tin, bismuth, chromium, molybdenum, manganese, iron, cobalt, and nickel; Examples include oxides, carbonates, and sulfates.

These are based on 100 parts by weight of the neutralized copolymer,
It is used in an amount of 5 to 1000 parts by weight, preferably 10 to 500 parts by weight.

Examples of organic fillers include starch, wheat flour, soybean glue, rubber powder, and wood flour, and examples of water-soluble resins include polyvinyl alcohol, carboxymethyl cellulose, hydroxyethyl cellulose, polyethyleneimine, and sodium polyacrylate. It will be done.

[Effects of the Invention] The adhesive composition of the present invention has excellent not only normal adhesive strength but also initial adhesive strength, so it can significantly shorten the working time especially when bonding by pressing, and can be used for continuous t-coating. This has the advantage of improving manufacturing efficiency when performing an adhesion process and, in some cases, also improving storage stability.

[Example] Next, the present invention will be explained in more detail with reference to Examples. In addition, the evaluation in each example was measured by the following method.

(1) Initial adhesive strength; according to the cross-wrap type adhesion test method, length 3 cm, width 2 cm
Adhesive composition 1809/Ga is applied to one side of each of two beech boards with a thickness of 1 cm, and the two are overlapped on this coated surface and clamped to bond them. After 5 minutes, the adhesive surface of each plate was pulled in the vertical direction, and the tension upon peeling was measured and taken as the initial adhesive strength.

(2) Normal adhesive strength: In the same manner as the initial adhesive strength, two beech boards are bonded together, and after 24 hours, they are peeled off and the tension at that time is measured to determine the normal adhesive strength.

(3) Evaluate by comparing the viscosity at 30°C immediately after preparing the storage-stable adhesive composition and the viscosity at 30'0 after being left at 40°C for 2 weeks, and by visually observing the formation of gel. did.

A B-type viscometer (No. 40-ter) was used as the viscometer.

Reference Example: In an autoclave with internal volume Le, if isobutylene is not used, all the monomers are added, and if isobutylene is used,
Monomers other than isobutylene were charged in the proportions shown in Table 1, cooled to -10'C, and the inside of the container was sufficiently degassed. Next, when using isobutylene, add a predetermined amount of it, and then add 460ml of acetonitrile as a solvent.
1+, adding 0.89 benzoyl peroxide as a catalyst, 4
The copolymerization reaction was carried out at 110°C for 2 hours while stirring at 00 rpm, and then the product was poured into water to obtain a copolymer. The viscosity average molecular weight and molar ratio of each structural unit of the obtained copolymer are shown in Table 1.

Next, a water-acetone solution (water:acetone weight ratio of 90:10) of sodium hydroxide with a concentration of 20% by weight was added to this copolymer in an amount appropriate to achieve a predetermined degree of neutralization.
In C, a neutralization reaction was carried out for 6 hours to obtain neutralized copolymers A-G having the degree of neutralization shown in Table 1.

Examples 1 to 7 Neutralized copolymers A-G (10% by weight) of the copolymers obtained in Reference Examples
Add 29 parts of aluminum hydroxide (Showa Light Metal Co., Ltd., registered trade name: Hisilite H-32) and 14 parts of rubber latex to 35 parts of solution), and heat at 20°C for 10 parts.
Mix for 1 minute to prepare the adhesive composition.

The adhesive strength and storage stability of the adhesive composition thus obtained were measured, and the results are shown in Table 2.

In this case, the rubber latex had a solid content of 5゜un%,
Viscosity 1 s o cps, R element B 220mtt sf
Ren-butadiene latex was used.

Examples 8 to 14 29 parts by weight of the same aluminum hydroxide used in Examples 1 to 7 was added to 35 parts by weight of the neutralized copolymer A-G (20% solution) obtained in Reference Examples. resin latex 14
Parts by weight were added and stirred at 20°C for 10 minutes to prepare an adhesive composition.

The adhesive strength and storage stability of the adhesive composition thus obtained were measured, and the results are shown in Table 3.

In this case, the resin latex had a solid content of 40% by weight,
An ethylene-vinyl acetate resin latex with an ethylene content of 20% by weight and a viscosity of 10-Ocps was used.

Examples 15-21 Neutralized copolymers A-G (20% by weight) obtained in Reference Examples
Solution) To 35 parts by weight, 29 parts by weight of aluminum hydroxide, the same as those used in Examples 1 to 7, 14 parts by weight of calcium carbonate, and 14 parts by weight of the same resin latex as used in Examples 8 to 14, An adhesive composition was prepared by stirring at 20° C. for 10 minutes.

The adhesive strength and storage stability of the adhesive composition thus obtained were measured, and the results are shown in Table 4.

Comparative example, 2 60 g of maleic anhydride was placed in an autoclave with an internal volume of 1α.
After cooling to -10°C and thoroughly degassing the inside of the container, 37 g of isobutylene was added, and acetonitrile was added as a solvent at 460 mA.

Add 0.89% of benzoyl peroxide as a catalyst and heat at 400 r.
The reaction was carried out at 110° C. for 2 hours with stirring at pI 11. By pouring this reaction mixture into water,
A copolymer having a viscosity average molecular weight of 35,000, 1.0 mol of isobutylene units, and 0.8 mol of maleic anhydride units was obtained.

Next, a 20% by weight solution of sodium hydroxide in water-acetone (weight ratio of water:acetone 90:10) was added to this, and a neutralization reaction was carried out at 90°C for 6 hours until the degree of neutralization was 0.
．． A neutralized product of 75 was obtained.

Neutralized product thus obtained (20% by weight solution) 35
29 parts by weight of aluminum hydroxide and Examples 1 to 7
Add 14 parts by weight of the same rubber latex used in Examples 8 to 15 or the same resin latex used in Examples 8 to 15, and
The adhesive composition was prepared by stirring at °C for 10 minutes.

The adhesive strength and storage stability of this product are shown in Table 5.

No. table *Viscosity at 30℃

Claims (1)

[Scope of Claims] 1 (A) A copolymer composed of at least one monomer unit selected from isobutylene units, styrene monomer units, and acrylic acid monomer units, and maleic acid monomer units. An adhesive composition prepared by blending (B) latex and (C) aluminum hydroxide into an incompletely neutralized product having a neutralization degree of 0.05 to 0.5. 2 (A) The degree of neutralization of a copolymer composed of at least one monomer unit selected from isobutylene units, styrene monomer units, and acrylic acid monomer units and maleic acid monomer units is 0. An adhesive composition comprising: (B) latex; (C) aluminum hydroxide; and (D) calcium carbonate.