JPS63241083A - Adhesive - Google Patents

Abstract

PURPOSE:To obtain an adhesive capable of maintaining excellent adhesive strength even in a humid environment, by using as its component a neutralized copolymer prepared through neutralization of a specified copolymer. CONSTITUTION:5-50mol.% maleate compound is copolymerized with 95-50mol.% compound having a terminal active double bond of the formula (e.g., isobutylene) in the presence of 0.01-10pts.wt., based on 100pts.wt. total monomers, catalyst (e.g., benzoyl peroxide) under a pressure of 0-50kg/cm<2>G at 30-200 deg.C for 0.5-20hr, thereby giving a copolymer having a viscosity-average molecular weight of 500-400,000. This copolymer is dispersed in a mixed solvent comprising 100pts.wt. water and 1-150pts.wt. organic solvent having a solubility in water of 9 or higher (e.g., acetone), and the obtained dispersion is mixed with an alkali (e.g., NaOH) for neutralization at 20-150 deg.C for 0.5-10hr to give a neutralized copolymer having a degree of neutralization of 0.05-0.5. 100pts.wt. this neutralized copolymer is then mixed with 5-500pts.wt. inorganic filler (e.g., TiO2) having a particle diameter of 50mum or smaller or 5-100pts.wt. epoxy compound (e.g., glycerin diglycidyl ether).

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an adhesive, and particularly to an adhesive that has excellent adhesive strength in a moist environment.

[Prior Art 1] It has been known that copolymers containing maleic acid compound units, such as neutralized isobutylene-maleic anhydride copolymers, can be used as adhesives (Japanese Patent Publication No. 4
9-34181, JP-A-49-25026).

However, the neutralized products of this conventionally known copolymer have a neutralization degree of 1 (acid value is O) or almost 1, and are easily soluble in water. Although it is easy to handle, when the neutralized product of this copolymer is used as an adhesive,
Since it has poor water resistance, it has the disadvantage that adhesive strength decreases in humid environments.

[Problems to be Solved by the Invention] The present invention provides an adhesive that maintains excellent adhesive strength, especially in a moist environment, in an adhesive made of a polymer containing maleic acid compound units. The purpose is to

[Means for solving the problem] Generally, when a polymer containing maleic acid compound units is used as an adhesive, it has been common knowledge that the acidity caused by the carboxylic acid group must be neutralized before use. , the present inventors attempted to keep this degree of neutralization low, and thereby the neutralized copolymer obtained by lowering the degree of neutralization within a certain range can be used as an adhesive with excellent water resistance. In addition, the present invention was completed based on the finding that it can be easily dissolved and handled using a mixed solvent of water and a specific organic solvent.

That is, the present invention provides (1) maleic acid compound units 5
Neutralization degree of 0.05 to 0.5 obtained by neutralizing a copolymer composed of ~50 mol% and 50 to 95 mol% of compound units having an active double bond at the molecular end Adhesive made of Japanese copolymer, (2) 5 to 50 maleic acid compound units
Mol% and compound unit with active double bond at the end of the molecule 5
(3) Malein Acid compound unit 5
Neutralization with a degree of neutralization of 0.05 to 0.5 obtained by neutralizing a copolymer composed of ~50 mol% and 50 to 95 mol% of compound units having an active double bond at the molecular end An adhesive consisting of a copolymer and an epoxy compound, and (4) a copolymer consisting of 5 to 50 mol% of maleic acid group compound units and 50 to 95 mol% of compound units having an active double bond at the molecular end. The present invention provides an adhesive comprising a neutralized copolymer and latex having a neutralization degree of 0.05 to 0.5 obtained by neutralization treatment.

The maleic acid compound units used in the present invention are maleic acid units, maleic acid mono- or diester units, and maleic anhydride units.

Since the double bonds of such maleic acid compounds cannot be directly bonded to each other under normal conditions, the compound alone usually has no polymerization ability at all.

However, when mixed with a compound having a terminal double bond, it exhibits polymerization activity, polymerizes, and is introduced into the copolymer as a component unit of the polymer.

Therefore, the proportion of maleic acid compound units in the copolymer does not exceed 50 mol% at most.

The maleic acid compound units in the present invention can be obtained by, for example, using maleic anhydride in a copolymerization reaction to once form a copolymer containing maleic anhydride units, and then forming other types of maleic acid compound units by hydrolysis or esterification reaction. It can be changed into a compound unit.

The acidity of the copolymer of the present invention varies widely depending on the type and composition ratio of the maleic anhydride compound units contained, and the amount of alkali required for complete neutralization varies accordingly.

Active double layer at the end of the molecule used in the copolymer of the present invention.

The compound having a bond is not particularly limited as long as it is a compound having a double bond that can be copolymerized with a maleic acid compound, and any compound that can be copolymerized can be used as an adhesive.

Specifically, the terminal double bond in such a compound may be one such as the formula % formula % (), and those having a double bond inside the carbon chain or a substituent on the terminal carbon atom are It cannot be used in the copolymer of the invention because copolymerization is difficult.

Examples of compounds having terminal double bonds used in the present invention include ethylene, isobutylene, styrene compounds, and acrylic compounds. These compounds are preferred, and mixtures of two or more of these can also be used.

The styrenic compound used in the production of the copolymer of the present invention is a compound containing a carbon atom skeleton represented by the formula in its molecular structure. Styrene, 0-chlorostyrene, etc. in which a lower alkyl group or /% lodene atom is introduced into the α-position carbon atom or benzene nucleus of formula (It) can be used.

The acrylic acid-based compound used to produce the copolymer of the present invention is a compound containing a carbon atom and an oxygen atom skeleton represented by the formula % in its molecular structure. g! , methacrylic acid, α-ethyl acrylic acid in which a lower alkyl group is introduced at the α-position carbon atom of the formula (I Esters such as methyl, ethyl acrylate, methyl methacrylate, alpha-ethyl ethyl acrylate, etc. can be used.

Examples of copolymers used in the present invention include (r, isobutylene-maleic acid compound copolymer, styrene compound-maleic acid compound copolymer, acrylic i-based compound-maleic acid compound copolymer) binary copolymers such as, isobutylene-styrene compound-acrylic acid compound copolymer, isobutylene-acrylic acid compound-maleic acid compound copolymer, styrene compound-acrylic acid compound-maleic acid compound Examples include terpolymer copolymers such as copolymers and quaternary copolymers such as isobutylene-styrene compound-acrylic acid compound-maleic acid compound copolymers.In these copolymers, Maleic acid compounds are never bonded adjacent to each other and always have a molecular structure with other monomers interposed between them.These copolymers include alternating copolymers, graft copolymers, and random copolymers. Any form such as a polymer or a block copolymer may be used.

These copolymers usually have a viscosity average molecular weight of 500 to
400,000, and the preferred viscosity average molecular weight is 1
, 000 to 200,000. Furthermore, the copolymer has a viscosity average molecular weight within the above range, and a content ratio of maleic acid compound units, which are essential constitutional units, in the copolymer is 5 to 50 mol%, particularly 10 to 50 mol%. % is preferable.

The copolymer in the present invention is produced, for example, as follows.

+fp 4-*Comparison A predetermined amount of each copolymer component except for isobutylene is charged into a reaction vessel, and usually cooled and sufficiently degassed. Next, a predetermined amount of isobutylene is added and stirred to carry out a copolymerization reaction. At this time, the reaction temperature is 3
0-200℃, preferably 45-200℃, reaction pressure is O-50 kg/C12, preferably 0-20 k
g/cz"G, reaction time is 0.5 to 20 hours, preferably 1 to 10 hours. In this copolymerization reaction, ethylbenzene, cumene, n-butylbenzene, etc. mixture, acetonitrile,
Solvents such as nitromethane, nitroethane, methyl ethyl ketone, acetone, N,N-dimethylformamide, dimethyl sulfoxide, benzoyl peroxide, lauroyl peroxide, cumene hydroperoxide, tertiary butyl hydroperoxide, dicumyl peroxide, azobisiso When using a catalyst such as butyronitrile, the amount used is not particularly limited, but is usually 0.01 to 10 parts by weight, preferably 0.01 to 10 parts by weight, based on 100 parts by weight of all monomers. 05 to 51 parts by weight. The catalyst may be used as is or diluted, and the catalyst may be added in its entirety at the beginning of the polymerization.
It may be added in portions during polymerization.

The neutralized copolymer, which is the main component of the adhesive of the present invention, is obtained by neutralizing a copolymer whose vI component is a maleic acid compound and a compound having a terminal double bond. The degree of neutralization is 0.05 to 0.50, preferably 0.10 to
It is necessary that it be in the range of 0.40. If the degree of neutralization of the neutralized copolymer is less than 0.05, the solvents that can dissolve it will be extremely limited, making handling difficult;
If the degree of neutralization exceeds 0.50, the water resistance will be poor, which is not preferable.

In addition, the degree of neutralization in the present invention refers to the amount by which the acid value of the copolymer decreases due to neutralization treatment (the difference between the acid value before neutralization treatment and the acid value after neutralization treatment). It is the ratio to the value.

The neutralization treatment with an alkali in the present invention can be performed in various ways, but for example, the copolymer is first mixed with a specific mixed solvent, specifically, water and an organic solvent having a solubility coefficient of 9 or more. A solution is prepared by dispersing the mixture in a solvent obtained by adding alkali, and then neutralizing and dissolving it by adding alkali.

Here, the solubility coefficient (δ) is a characteristic value of a liquid that is a measure of the miscibility between liquids, and is expressed by the formula where E is the molecular cohesive energy of the liquid and V is the molecular volume, solubility coefficient (δ) = (E /V) is given by l/2.

When preparing a solution in this way, the solubility coefficient is 9.
The above organic solvents are preferably used, such as ethyl acetate, methylcyclohexanone, methyl ethyl ketone, 7ran, methyl acetate, acetone, cyclohexanone, cyclopentanone, ethylene glycol monoethyl ether,
Dimethylformamide, dimethylsulfoxide, nitroethane, nitromethane, acetonitrile, chloro7cetonitrile, etc. can be used.

When the hydrogen bonding strength of these organic solvents is evaluated in three stages (weak, medium, strong), those with weak or medium hydrogen bonding strength are preferable as organic solvents. Among those mentioned above, methyl ethyl ketone, acetone, acetonitrile and the like are particularly preferred. The mixed solvent in which the copolymer is dispersed is obtained by mixing the above organic solvent and water. The mixing ratio of the two varies depending on various conditions, but usually the solubility coefficient is 9 with respect to 100 parts by weight of water.
1 to 150 parts by weight of the above organic solvent, preferably 5 to 1 part by weight.
00 parts by weight are used.

Next, the copolymer dispersed in the mixed solvent is neutralized using an alkali to produce a neutralized product of the copolymer. This neutralized copolymer is dissolved in the mixed solvent to form a uniform solution. As the alkali used at this time, alkali metal compounds such as sodium hydroxide, potassium hydroxide, sodium carbonate, and sodium acetate, ammonia, ammonium hydroxide, urea, 1,000 urea, and organic amines can be used. The amount of the alkali to be used should be determined depending on the desired degree of neutralization (within a range of 0.05 to 0.5), taking into account the type of alkali used, the conditions of the neutralization reaction, etc. Moreover, the reaction temperature of this neutralization reaction is usually 20-15
0°C, reaction time 0.5-10 hours ftf11. : Preferably set.

The adhesive of the present invention thus obtained has a degree of neutralization of 0.
05 to 0.5 neutralized copolymer alone, and those consisting of the neutralized copolymer as the main component and further added with an inorganic filler, epoxy compound, or latex as a modifier.

As the inorganic filler used as a modifier in the adhesive of the present invention, compounds of divalent or higher metals, carbon black or sulfur powder, etc. can be used. Metal compounds include copper, silver, magnesium, calcium, strontium, barium, zinc, cadmium, aluminum, titanium, norconium, tin, bismuth, chromium, molybdenum, manganese, iron,
Oxides, hydroxides, carbonates, sulfates, etc. of cobalt, nickel, etc. can be used.

These amounts are 5 to 50 parts by weight per 100 parts by weight of the neutralized copolymer.
It can be used in an amount of 0 parts by weight, preferably 10 to 300 parts by weight.

These fillers are produced by physical attraction between their surface and the polar carboxyl groups of the neutralized copolymer.
Increases the adhesive strength of the adhesive of the invention.

For this reason, the smaller the particle size of the inorganic filler, the better;
Dust of 50 μm or less is preferably removed by use.

The epoxy compound added as another modifier to the adhesive of the present invention is preferably a compound having two or more epoxy groups, and the epoxy group reacts with the polar group of the neutralized copolymer of the present invention. It has the effect of cross-linking.

The epoxy compound added as another modifier to the neutralized copolymer of the present invention is preferably a compound having two or more epoxy groups, and this epoxy group reacts with the polar group of the neutralized copolymer. Forms a crosslinked structure and strengthens the bonded area. Examples of such epoxy compounds that can be used include diglycidyl etherified glycols such as glycerin diglycidyl ether, ethylene glycol diglycidyl ether, and polyethylene glycol diglycidyl ether, and diglycidyl etherified compounds of compounds having a carboxyl group.

These amounts are 5 to 100 parts by weight per 100 parts by weight of the neutralized copolymer.
It can be used in an amount of 10 to 70 parts by weight, preferably 10 to 70 parts by weight.

The latex added as another modifier to the neutralized copolymer of the present invention is one that imparts adhesive strength to the neutralized copolymer, and the dispersoid in the latex is rubbery or resinous. There is something.

Any rubbery polymer can be used as a dispersoid in the rubber latex, such as styrene-butadiene copolymers, styrene-isoprene copolymers, polyurethane elastomers, polychloroprene, nitrile rubber, butadiene rubber, methyl methacrylate-butadiene copolymers, etc. Polymers, natural rubber, etc. can be suitably used.

As the dispersoid for the resin latex, for example, polyvinyl acetate, ethylene-vinyl acetate copolymer, bo-177 acrylic ester, polymethacrylic ester, etc. can be used.

These latexes are a type of colloidal sol that uses rubber or resin components as a dispersant and water as a dispersion medium, and has a content of 5 to 50 parts by weight in terms of dispersoid per 100 parts by weight of the neutralized copolymer.
It is used in an amount of 0 parts by weight, preferably 10 to 300 parts by weight.

Other additives used in the adhesive of the present invention include organic fillers such as starch, wheat flour, soybean glue, rubber powder, and book flour; Water-soluble resins such as imine and sodium polyacrylate can also be used as appropriate to change the properties of the adhesive.

[Example] The present invention will be explained in more detail with reference to Examples.

Examples 1 to 7, Comparative Examples 1 and Reference Examples 1 to 3 In an autoclave with an internal volume of 11, predetermined amounts of the components shown in Table 1 excluding isobutylene when isobutylene is used, 460 cc of acetonitrile as a solvent, and benzoyl peroxide as a catalyst. 0.6 g was charged and cooled to -10°C, and the inside of the container was sufficiently degassed. Next, when isobutylene was used, a predetermined amount of isobutylene was added, and a copolymerization reaction was carried out at 110° C. for 2 hours while stirring at 400 rpm.

Thereafter, the product was poured into water to obtain a copolymer. The viscosity average molecular weight, iso, butylene content of the obtained copolymer,
Table 1 shows the amounts of styrene, methyl acrylate, and maleic acid in molar ratios.

Afterwards, this copolymer 25. Sodium hydroxide necessary to achieve a predetermined degree of neutralization and the mixed solvent shown in Table 1 were added to the solution, and the mixture was heated and dissolved at 90° C. for 3 hours. Add 50 g of slaked lime as a filler to this solution and add 37.5 g of water.
g was added and stirred to obtain a highly viscous solution.

Next, a lauan wood veneer with a thickness of 0.75 l and a thickness of 0.51
A total of three veneers, the shoulder veneer and the lauan veneer with a thickness of 0.75 am, were opened and the high viscosity solution (adhesive) was applied to the
．． Plywood was prepared by applying the coating to a thickness of 3H and joining it sequentially, pressing it at 10kg/cJI2 for 10 minutes, and then applying 12
A test piece was prepared by pressing at 0° C. with 10Ag/c shoulder 2 for 30 minutes. Using this test piece, its adhesive strength was measured in accordance with JAS2M. The results are shown in Table 1.

Examples 8 to 14 and Reference Examples 4 to 6 In an autoclave with an internal volume of 11, when using isobutylene, predetermined amounts of the components shown in Table 2, excluding isobutylene,
Acetonitrile 460 as a solvent and benzoyl peroxide O, E, etc. as catalysts were charged, and while cooling to -10°C, the inside of the container was sufficiently degassed. Next, if isobutylene is used, add a predetermined amount of isobutylene and add 40
The copolymerization reaction was carried out at 110° C. for 2 hours while stirring at 0 rpm+.

Next, the product was poured into water to obtain a copolymer. Table 2 shows the viscosity average molecular weight, isobutylene content, styrene content, methyl acrylate content, and maleic acid content of the obtained copolymer in molar ratio.

Thereafter, sodium hydroxide necessary to achieve a predetermined degree of neutralization and the mixed solvent shown in Table 2 were added to this copolymer 25y, and the mixture was heated and dissolved at 90° C. for 3 hours. Inorganic fillers, epoxy compounds, or latex shown in Table 1 were added to this solution and stirred to obtain a highly viscous solution.

Next, a lauan wood veneer with a thickness of 0.7511 and a thickness of 1.5i
The above high viscosity solution (adhesive) was placed between a total of three veneers: a lauan veneer with a thickness of i and a lauan veneer with a thickness of 0,7511!1.
was applied to a shoulder thickness of 0.3 m and joined in sequence to make plywood.

This was then pressed at 10 kg/cm2 for 10 minutes, and then at 120°C and 10 ky/cm2 for 30 minutes to form a test piece.

Using this test piece, the adhesive strength was measured in accordance with JAS2M. The results are shown in Table 2.

[Advantageous Effects of the Invention 1] The adhesive of the present invention exhibits high adhesive strength and excellent adhesive properties, and also has good water resistance. Moreover, since it is easily dissolved in a specific mixed solvent, the workability is also extremely good.

Therefore, the adhesive of the present invention can be widely and effectively used in various industrial fields that require adhesives.

Claims (1)

[Claims] 1 5 to 50 mol% of maleic acid compound units and 50 to 95 mol% of compound units having an active double bond at the end of the molecule
The degree of neutralization obtained by neutralizing a copolymer composed of
An adhesive consisting of a neutralized copolymer of 0.05 to 0.5. 2. The adhesive according to claim 1, wherein the compound unit having an active double bond at the end of the molecule is a unit of at least one compound selected from isobutylene, styrene compounds, and acrylic acid compounds. 3 Neutralization degree 0.0 obtained by neutralizing a copolymer composed of 5 to 50 mol% of maleic acid compound units and 50 to 95 mol% of compound units having an active double bond at the molecular end.
An adhesive comprising a neutralized copolymer of 5 to 0.5 and an inorganic filler. 4 Neutralization degree of 0.0 obtained by neutralizing a copolymer composed of 5 to 50 mol% of maleic acid compound units and 50 to 95 mol% of compound units having an active double bond at the molecular end
An adhesive comprising a neutralized copolymer of 5 to 0.5 and an epoxy compound. 5 5 to 50 mol% of maleic acid compound units and 50 to 95 mol% of compound units having an active double bond at the end of the molecule
The degree of neutralization obtained by neutralizing a copolymer composed of
An adhesive consisting of a neutralized copolymer of 0.05 to 0.5 and latex.