JPS5936668B2 - Novel adhesive composition - Google Patents

Description

[Detailed description of the invention] The present invention relates to novel adhesive compositions.

More specifically, vinyl acetate (vinyl acetate) using α-olefin-maleic anhydride copolymer or its derivative as a protective colloid
The present invention relates to an adhesive composition comprising a co)polymer resin emulsion and a maleic acid imide copolymer, as well as an adhesive composition further containing an epoxy compound, and is particularly suitable as a wood adhesive. It is something. Conventionally, urea resin adhesives, melamine resin adhesives, phenol resin adhesives, resorcinol resin adhesives, vinyl acetate resin adhesives, casein adhesives, and the like have been widely used as adhesives for wood.

These adhesives are used depending on the purpose of the adhesive product, processability, required degree of water resistance, etc. However, thermosetting adhesives such as urea resins, melamine resins, and phenol resins require heating and compression during bonding, and are not suitable for bonding thick materials.

Although the resorcinol resin adhesive has extremely good water-resistant adhesive strength, it requires a pressure test time of 16 hours or more, which poses a problem in terms of work efficiency. In addition, vinyl acetate resin adhesive,
Casein adhesives are capable of pressure detection adhesion, but have the disadvantage of low water-resistant adhesive strength. Furthermore, phenolic resins, resorcinol resins, casein adhesives, and the like have the disadvantage that the adhesive contaminates the adherend, reducing the commercial value of the product.

As a result of intensive research to improve the drawbacks of these conventional adhesives, the inventors of the present invention have found that there is no contamination of the adherend by the adhesive, it is possible to bond with a short pressure test, and it is highly water resistant. A composition consisting of a maleic acid imide copolymer and latex was discovered as an adhesive composition having adhesive strength, and a patent application (Japanese Patent Application No. 130,639/1984) was previously filed.

However, the initial tack (adhesive force immediately after lamination) of this adhesive composition is much lower, and improvements have been desired in terms of pressure detection and short-time pressing, ie, improvement in work efficiency.

As a result of further research, we discovered a new adhesive composition that has an extremely high initial resistance without losing the characteristics of the adhesive composition, and completed the present invention. . That is, an adhesive composition comprising a vinyl acetate (co)polymer resin emulsion containing an α-olefin-maleic anhydride copolymer or a derivative thereof as a protective colloid and a maleic acid imide copolymer, and the above-mentioned adhesive composition. Adhesive compositions containing an epoxy compound containing two or more epoxy groups in the molecule have extremely high initial tack, do not contaminate the adherend with the adhesive, and have excellent cold-pressure adhesion and water-resistant adhesion. was found to be extremely superior.

The components constituting the adhesive composition of the present invention will be explained below. The vinyl acetate (co)polymer resin emulsion containing α-olefin monomaleic anhydride copolymer or its derivative as a protective colloid used in the present invention is as follows.

First, the polymer used as a protective colloid for emulsion is α-olefin (here, α-olefin is a linear or branched polymer having 2 to 8 carbon atoms, preferably 2 to 8 carbon atoms).
6, such as ethylene, propylene, 1-
Butene, isoptene, 1-benzene, 2-methyl-1-
butene, 3-methyl-1-butene, 1-hexene, isoprene, styrene, etc., but isobutene is particularly preferred) and maleic anhydride, and the following copolymers derived from the copolymer: Examples include derivatives.

That is, as derivatives of maleic acid copolymers, maleic acid imide copolymers obtained by reacting the copolymers with nitrogen compounds such as ammonia or amines in a vapor atmosphere or medium, and α-olefin monoanhydride. In addition to the esterified copolymer obtained by reacting the maleic acid copolymer with alcohol, the esterified product of the maleic acid imide copolymer, and various copolymers thereof can be mixed with hydrogen peroxide, ammonium persulfate, Examples include those pre-cleaved with potassium persulfate. These copolymers used as protective colloids in emulsions are insoluble in water, and can be dissolved by adding basic substances such as caustic alkali, ammonia, amines, alkali carbonates, ammonium carbonates, alkali acetates, and ammonium octaacetates. .

Among these basic substances, caustic alkali or ammonia is preferred, and the amount added is preferably 0.3 to 0.8 equivalents relative to the carboxyl group of the copolymer. The thus prepared α-olefin-maleic anhydride copolymer or its derivative was used as a protective colloid to bind vinyl acetate (
To produce the co-polymer resin emulsion, a known polymerization method that has been established as a general method for producing vinyl acetate resin emulsions can be employed.

That is, by adding a polymerization initiator to the above protective colloid aqueous solution, and adding vinyl acetate monomer or another vinyl monomer that can be copolymerized with the vinyl acetate monomer at the initial stage or continuously. Polymerize.

As the polymerization initiator used in this case, well-known initiators such as peroxides such as persulfates and hydrogen peroxide, and redox catalysts formed by a combination of peroxides and reducing agents can be used.

Vinyl monomers that can be copolymerized with vinyl acetate include:
Examples include acrylic ester, methacrylic ester, vinyl chloride, vinyl versatate, α-olefin or glycidyl methacrylate having a functional group, N-methylolacrylamide, methacrylic acid monoalkyl maleate, and hydroxyalkyl ester. The concentration of the emulsion obtained by this method can be changed as appropriate in the range of 25 to 70% depending on the application and required performance.

The amount of the emulsion blended in the adhesive composition of the present invention is 10 to 20,000 parts by weight in terms of solid content per 100 parts by weight of the maleic acid imide copolymer (described below). ) is suitable, and 50 to 1000 parts by weight is particularly desirable. When the amount added is less than 10 parts by weight or more than 20,000 parts by weight, the viscosity of the adhesive composition becomes too high in the former case and too low in the latter, resulting in poor workability during bonding, and in both cases, the viscosity of the adhesive composition becomes too high. This is undesirable because it reduces tack and adhesive strength. The maleic imide copolymer used in the present invention is a multicomponent copolymer containing units based on maleic imide and/or N-monosubstituted maleic imide and units based on α-olefin in the main chain.

The N-monosubstituted maleic imide used is obtained by substituting the hydrogen atom bonded to the imide nitrogen atom of maleic imide with an appropriate substituent, and the substituent includes alkyl, phenyl, hydroxyalkyl, Included are groups such as hydroxyphenyl, carboxyalkyl, carboxyphenyl, primary aminoalkyl, secondary aminoalkyl, tertiary aminoalkyl, and the like.

Among these combinations of units based on maleic acid imide and/or N-monosubstituted maleic acid imide, it is preferable in the present invention to include only units based on maleic acid imide.

The α-olefin used in the present invention refers to an olefinic unsaturated compound having a double bond at the α-position, and includes ordinary α-olefins such as vinyl ether, vinyl ester, vinyl halide, allyl ether, allyl ester,
Styrene, alkyl-substituted styrene, acrylonitrile,
Included are (meth)acrylic esters, (meth)acrylic amides or substituted amides, butadiene, isoprene, and the like. Among these, carbon number is 2 to 8, preferably 2
linear or branched aliphatic α-olefins having ~6, such as ethylene, propylene, n-butene, isobutylene, n=benzene, 2=methyl-1-butene,
Preferred are n-hexene, 2-methyl-1-benzene, 3-methyl-1-benzene, 4-methyl-1-benzene, 2-ethyl-1-butene, and the like. Among these, isobutylene is particularly preferred. Moreover, isobutylene herein also includes return BB containing isobutylene. Moreover, one type or two or more types of α-olefins may be used.

The maleic imide copolymer used in the present invention is maleic imide and/or N-substituted maleic imide, α-
Although olefin is an essential component, unsaturated acid units such as maleic anhydride may be incorporated into the maleic imide copolymer depending on the application of the adhesive composition.

The maleic acid imide copolymer used in the present invention includes the above-mentioned maleic imide and/or N-substituted maleic imide, one or more α-olefins, and, if necessary, an unsaturated acid such as maleic anhydride. by direct copolymerization, but it is also possible to prepare them by other methods giving copolymers of the same composition.

For example, after copolymerizing α-olefin and maleic anhydride by a known method, the resulting copolymer is mixed with a suitable nitrogen compound that provides the desired maleic acid imide structure and N-substituted maleic acid imide structure. The same products obtained by direct copolymerization are obtained when the reaction is carried out in a nitrogen compound vapor atmosphere or in a medium. Such nitrogen compounds include ammonia, primary aliphatic amines,
These include aromatic amines, hydroxyalkylamines, aminophenols, aliphatic aminocarboxylic acids, lactams, aromatic aminocarboxylic acids, aliphatic diamines, N-substituted aliphatic diamines, N-N-substituted aliphatic diamines, and the like. The content of maleic imide and/or N-substituted maleic imide units in the maleic imide copolymer used in the present invention is suitably 5 to 50 mol%, preferably 10 to 50 mol%. The degree of polymerization of the maleic acid imide copolymer is suitably from 200 to 10,000, preferably from 400 to 5,000, based on the number of bonded monomers.

Maleic acid imide copolymer is soluble in aqueous alkaline solution, so it contains one or more alkaline substances such as caustic alkali, alkali carbonate, ammonium carbonate, calcium carbon, slaked lime, ammonia, or organic amines. It is preferable to use it by dissolving it in an aqueous solution.

The compound having two or more epoxy groups in the molecule used in the present invention is preferably partially water-soluble, or a water-soluble epoxy compound that does not completely phase separate in the adhesive composition of the present invention.

For example, when the following highly water-soluble epoxy compound is used, the adhesive exhibits good water-resistant adhesion.
Namely, glycerin diglycidyl ether, ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, glycerin triglycidyl ether, propylene glycol diglycidyl ether,
Di- or triglycidyl etherified products of polyhydric alcohols such as polypropylene glycol diglycidyl ether and trimethylolpropane triglycidyl ether;
Examples include glycidyl esters of compounds containing two or more carboxyl groups in the molecule. In the present invention, even if the epoxy compound has low solubility in water, it is also possible to use an epoxy compound that can uniformly disperse the adhesive composition of the present invention.

Namely, epoxy resins from cyclohexene, diglycidyl ether of nobisphenol A, alicyclic epoxy resins, dimer acid glycidyl ester type epoxy resins,
Nitrogen-containing epoxy resin, polybutadiene type epoxy resin,
Examples include epoxy alkyl ester epoxy resins, ut/tan modified epoxy resins, and metal-containing epoxy resins. In addition, when caustic alkali is used as a solubilizer in the present invention, chlorohydrin ether compounds which are precursors of epoxy compounds, such as glycerin dichlorohydrin ether, glycerin trichlorohydrin ether, ethylene glycol dichlorohydrin ether, etc. ,
Propylene glycol dichlorohydrin ether and the like can also be used.

The amount of the epoxy compound added is 1 to 200 parts by weight, preferably 1 to 100 parts by weight of the maleic acid imide copolymer.
The amount is preferably 0 to 100 parts by weight, and the amount added is adjusted as appropriate depending on the degree of water resistance required. The solid content concentration of the adhesive composition of the present invention is suitably 10 to 80%, preferably 20 to 70%, in view of the viscosity, workability, adhesive strength, etc. of the adhesive composition. The adhesive composition of the present invention prepared in this way has the following characteristics: (1) it dries quickly after application due to the gelling properties of the maleic acid imide copolymer aqueous solution, has excellent initial adhesion, and has excellent initial adhesive properties; It also shows excellent adhesion performance in short-time cold compaction. (2) If the content of imide groups in the maleic acid imide copolymer and the type and amount of solubilizer added are appropriately selected, it can be used as an adhesive in an aqueous solution state;
The reaction between the maleic acid imide copolymer and the epoxy compound becomes easy, and when this is used as an adhesive, a high degree of water-resistant adhesive strength is developed. (3) When a vinyl acetate resin emulsion containing α-olefin-maleic anhydride copolymer (or its derivative) as a protective colloid is added to the maleic acid imide copolymer, initial tact (adhesion strength immediately after lamination) is achieved. It shows excellent adhesion performance even at room temperature with short cold pressing. Moreover, when this emulsion is used, it exhibits extremely high water-resistant adhesive strength compared to when a general vinyl acetate resin emulsion is used. (4
), the maleic acid imide copolymer is made into an aqueous solution and then prepared into an adhesive composition, but even when a solubilizer is used, P
Since it is used at around H7, there is no contamination of the adherend by the acid or alkali of the adhesive, and the commercial value of the product is not impaired. (5) Since the adhesive composition of the present invention is an aqueous solution, the atmosphere in which it is used is extremely clean, and it does not cause deterioration of the working environment unlike organic solvent-based or formalin condensed resin-based adhesives. . When actually using the above adhesive composition as a wood adhesive, wood powder, wheat flour,
Organic fillers such as soybean glue, calcium carbonate, gypsum,
It is possible to adjust the viscosity and solid content concentration of the adhesive by appropriately adding an inorganic filler such as clay.

There are no fixed rules for the order of addition of each component in the adhesive composition, except for the epoxy compound, and the order of addition can be selected completely freely, and the viscosity and adhesive strength are hardly affected by this. Since the epoxy compound has a limited pot life, it is desirable to mix it immediately before using the adhesive composition.

The adhesive composition of the present invention can be applied to plywood, laminated veneer wood, laminated wood,
It is particularly suitable as an adhesive for wood products such as flat panels, particle boards, fittings, sports equipment, and other wood products, but it can also be used for other materials such as cardboard, paper, cloth, metal, etc.
Ceramics, inorganic boards (such as asbestos boards, rock wool boards, asbestos slate boards, pulp cement boards, calcium silicate boards, gypsum boards, concrete boards, etc.), plastic boards (such as melamine resin boards, PVC tiles, etc.),
It can also be applied to bonding glass plates, wood wool plates, etc.

Further, the adhesive of the present invention is effective not only when bonding the same materials among the adherends, but also when bonding two or more types of materials. The present invention will be explained in more detail with reference to Examples below, but the present invention is not limited thereto.

Example 1 Isobutene monomaleic anhydride copolymer (polymerization degree 4001
powder) at 60°C under an ammonia atmosphere,
The mixture was further heated at 185° C. to produce a maleic acid imide copolymer.

The content of maleic acid imide units in this maleic acid imide copolymer (hereinafter abbreviated as imide content) is 23 mol%
It was hot. This copolymer aqueous solution (concentration 20%, 0.4 equivalent of ammonia added to carboxyl group) 500y
was charged into a polymerization tank, vinyl acetate 3001 was added dropwise in a conventional manner using ammonium persulfate 5f as an initiator, and emulsion polymerization was carried out to prepare a vinyl acetate resin emulsion (solid content: about 50%).

The above maleic acid imide copolymer 25r125
After adding the vinyl acetate resin emulsion 75y and calcium carbonate 607% to an aqueous solution obtained by mixing 57% ammonia water and 707% water and heating and dissolving the mixture at 90°C, water-soluble epoxy resin (glycerin diglycidyl ether) 12% was added.
An adhesive composition was prepared by adding 7 and mixing well. For comparison, an adhesive composition was prepared in the same manner using a styrene-butadiene copolymer latex (concentration 50% by weight) in place of the vinyl acetate resin emulsion. This adhesive composition was applied to 3 mm thick lauan plywood for 15 minutes.
07/A was applied, the main fiber axes of the front and back plates were bonded so that they were parallel, and cold pressure was applied at 10 kg/Cd for 5 minutes. Immediately after that, a test piece was cut out according to the JAS for plywood, and the initial test was performed using the tensile shear method. Tack was measured.

Moreover, the thickness of the above adhesive composition is 107! 2007/ml was applied to a Tm birch wood grain board, bonded together so that the main fiber axes were parallel, and cold pressed for 30 minutes under a load of 10 kg/Cnl.

After cold pressing and curing for 7 days at a humidity of 65% and a temperature of 20℃, J
A test piece was cut out according to ISK-6852, and the adhesive strength was measured by the compression shear method. Table 1 shows the initial tack and adhesive strength measurement results. Example 2 After reacting ethylene-maleic anhydride copolymer (degree of polymerization 500, powder) and ammonia at 60°C,
A maleic acid imide copolymer (imide content: 31 mol%) was prepared by heating at 0°C.

This copolymer 307, 25% ammonia water 3y1, calcium carbonate 37, and water 64y were mixed and dissolved by heating at 90°C. To this solution, 120V of the vinyl acetate resin emulsion prepared in Example 1 and 90V of calcium carbonate were sequentially added and mixed, and then water-soluble epoxy resin (ethylene glycol diglycidyl ether) 157 was added and mixed to obtain an adhesive composition. . For comparison, a general vinyl acetate resin emulsion obtained by emulsion polymerization in the same manner as in Example 1 was used, using polyvinyl alcohol (PVA-217 manufactured by Kuraray Co., Ltd.) as a protective colloid, and in accordance with the above method. Created an adhesive composition. Table 2 shows the results of the same tests as in Example 1 using these adhesive compositions.

Example 3 An aqueous solution (concentration 20%) obtained by adding 0.4 equivalents of ammonia to the carboxyl group of an ethylene-maleic anhydride copolymer or a reaction between a styrene-maleic anhydride copolymer and butanol. esterified product (
An aqueous solution (concentration 20%) obtained by dissolving esterification rate (42 mol%) in water in the same manner was used as a protective colloid and subjected to emulsification in the same manner as in Example 1 to prepare a vinyl acetate resin emulsion.

Adhesive compositions were prepared using these emulsions in the same manner as in Example 1, and initial tack and adhesive strength tests were conducted. The results are shown in Table 3.

Example 4 Using the maleic acid imide copolymer prepared in Example 1 as a protective colloid, copolymer resin emulsions of vinyl acetate, ethylene, pinyl chloride, vinyl versatate, and butyl acrylate were emulsion polymerized by a conventional method. I made it.

Both have a copolymerization ratio of 20% (weight) to vinyl acetate,
The concentration is 50% (by weight). Adhesive compositions were prepared using these copolymer resin emulsions in the same manner as in Example 1, and the initial tack and adhesive strength were measured. Table 4 shows the results.

Example 5 Styrene-maleic anhydride copolymer (degree of polymerization: 600, powder) and ammonia were reacted at 50'C, and then further heated at 180°C to form a maleic acid imide copolymer (
The imide content was 16 mol%).

This copolymer 307, 25% ammonia water 1057, and water 60y were mixed and dissolved by heating at 90°C. Add to this solution the vinyl acetate-ethylene copolymer resin emulsion (concentration 50% by weight) 907 prepared in Example 4 and calcium carbonate 60.
After sequentially adding and mixing y, 10y of water-soluble epoxy resin (ethylene glycol diglycidyl ether) was added and mixed to obtain an adhesive composition. Using this adhesive composition, laminate veneer, melamine resin board/plywood, pulp cement board/
Table 5 shows the results of gluing the plywood and measuring the adhesion force.

Example 6 Isoptene-maleic anhydride copolymer (polymerization degree 1000, powder) was reacted at 60°C in an ammonia atmosphere, and then heated at 180°C to form a maleic acid imide copolymer (imide content 31 mol%). ) was created.

This copolymer 30y) 25% ammonia water 5V) Water 7
0V was mixed and dissolved by heating at 90°C.

After sequentially adding and mixing 90V of the vinyl acetate resin emulsion (concentration 50%) prepared in Example 1, 90V of calcium carbonate, 80V of wheat flour, and 120V of water to this solution, 80V of water-soluble epoxy resin (glycerin diglycidyl ether)
y was added and mixed to obtain an adhesive composition. Apply 120y/wl of this adhesive composition to the base plywood to a thickness of 0.2mm.
After laminating decorative veneers (wood species: teak, cypress, zelkova), they were heat-pressed at 110°C, 10k9/Cd, for 60 seconds to create decorative plywood.

This decorative plywood was tested according to the JAS method, and the results are shown in Table 6. Example 7 Maleic acid imide copolymer 20V prepared in Example 6)
25% ammonia water 2f7, calcium carbonate 3y, water 7
5V was mixed and dissolved by heating at 90°C.

To this solution, 90V of the vinyl acetate resin emulsion (concentration 50% by weight) prepared in Example 1, gypsum 1301, and 5V of titanium oxide were sequentially added and mixed, and then 5V of water-soluble epoxy resin (ethylene glycol diglycidyl ether) was added and mixed. An adhesive composition was obtained. This adhesive composition was applied to the base plywood at 100 y/m'', semi-dried with hot air at 80°C for 10 seconds, then printed paper with a weight of 24 V/d was attached and hot-pressed at 90°C for 3 seconds to form a printed paper overlay. I made decorative plywood.

This printed paper overlay decorative plywood was tested according to the JAS method, and the results are shown in Table 7. Example 8 A copolymer resin emulsion of vinyl acetate and glycidyl methacrylate was prepared in the same manner as in Example 1 using an ethylene-maleic anhydride copolymer as a protective colloid.

The copolymerization ratio to vinyl acetate was 15% (by weight) and the concentration was 50% (by weight). The maleic acid imide copolymer 30V prepared in Example 1, 31 parts of 125% ammonia water, 57 parts of calcium carbonate, and 62 parts of water were mixed and dissolved by heating at 90°C.

Vinyl acetate-glycidyl methacrylate copolymer resin emulsion 80? which was obtained by emulsion polymerization in this solution first? An adhesive composition was obtained by sequentially adding and mixing 90y of calcium carbon.

Using this adhesive composition, initial tack and adhesive strength tests were conducted in the same manner as in Example 1, and the results are shown in Table 8.

Example 9 Isoprene-maleic anhydride copolymer (degree of polymerization 1600
, powder) in the same manner as in Example 1. A maleic acid imide copolymer (imide content: 43 mol%, degree of polymerization: 400) was added with water and ammonia (to the carboxyl groups of the copolymer). 0.5 equivalent) was added to prepare an aqueous solution.

This aqueous solution was used as a protective colloid and vinyl acetate was emulsion polymerized by a known method to prepare a vinyl acetate resin emulsion (concentration 60% by weight).

Separately from the above, isoptene-maleic anhydride copolymer (polymerization degree 400, powder) was heated to 60% in an ammonia atmosphere.
After reacting at .degree. C., the mixture was further heated at 190.degree. C. to produce a maleic acid imide copolymer (imide content: 46 mol%).

This copolymer 307, 25% ammonia water 107, water 6
An adhesive composition was obtained by adding and mixing the previously prepared vinyl acetate resin emulsion 60y and calcium carbonate 60y to an aqueous solution prepared by mixing 07 and heating and dissolving the mixture at 95°C.

Using this adhesive composition, initial tack and adhesive strength tests were conducted in the same manner as in Example 1, and the results are shown in Table 9.

Example 10 Isobutene monomaleic anhydride copolymer (degree of polymerization 600,
powder) and ammonia at 60°C, and further heated to 180°C.
A maleic acid imide copolymer (imide content: 30 mol%) was prepared by heating at .degree.

Water and ammonia (0.4 equivalents relative to carboxyl groups) are added to this copolymer and dissolved by heating, and 10% by weight of hydrogen peroxide is added to the copolymer to cause a cleavage reaction, resulting in low polymerization. Aqueous solution of maleic acid imide copolymer (
A degree of polymerization of 80 and a concentration of 30% were obtained. Using this aqueous solution, emulsion polymerization of vinyl acetate was carried out in a conventional manner to synthesize a vinyl acetate resin emulsion (concentration 60%). Example 1
maleic acid imide copolymer (imide content 2
3 mol %) 307, 25% ammonia water 37, calcium carbonate 37 and water 707 were mixed and dissolved by heating at 90°C. To this solution, 160f1 of vinyl acetate resin emulsion and 100f7 of calcium carbonate prepared previously were added and mixed in order, and then water-soluble epoxy resin (glycerin diglycidyl ether) 157 was added and mixed to obtain an adhesive composition.
Using this adhesive composition, initial tack and adhesion tests were conducted in the same manner as in Example 1, and the results are shown in Table 10.

Claims (1)

[Scope of Claims] 1. An adhesive composition comprising a vinyl acetate (co)polymer resin emulsion and a maleic acid imide copolymer, which is a protective colloid of an α-olefin-maleic anhydride copolymer or a derivative thereof. 2. From a vinyl acetate (co)polymer resin emulsion containing an α-olefin-maleic anhydride copolymer or its derivative as a protective colloid, a maleic acid imide copolymer, and an epoxy compound containing two or more epoxy groups in the molecule. adhesive composition.