JPS60255875A - Adhesive composition - Google Patents

Abstract

PURPOSE:To provide the titled compsn. having excellent stability and resistance to water and heat, consisting of a water-soluble high-molecular material and/or an aq. dispersion of a high-molecular material, a specified self-emulsifiable polyurethane/amino resin copolymer (isocyanurate-modified compd.) and additives. CONSTITUTION:A prepolymer having a residual isocyanate content of 20-30% and contg. isocyanate groups at its terminals obtd. by reacting an alkoxy-polyalkylene glycol having an MW of 250-4,000 and the formula (wherein R1 is alkyl, unsaturated hydrocarbon group; R2 is alkylene) with an org. polyisocyanate, is reacted with an alcohol-etherified amino/formaldehyde resin contg. active hydrogen at a concn. of 7.13mm.d/g or below (if desired, in the presence of an isocyanurate-forming catalyst) to obtain a self-emulsifiable polyurethane/amino resin copolymer (isocyanurate-modified compd.) A water-soluble, high-molecular material and/or an aq. dispersion of a high-molecular material, the above copolymer and additives such as stabilizer, thickener, filler, etc. are blended together.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an adhesive composition having excellent water resistance, heat resistance, etc.

More specifically, the present invention relates to an aqueous adhesive composition having excellent processability, workability, physical properties, etc. for molding wood, plastics, etc.

Conventionally, urea resins, urea-melamine cocondensation resins, phenolic resins, etc. have been used as adhesives for wood and its secondary processing, for plywood, and for particle boards, but these adhesives do not contain formaldehyde during product processing. emits,
Furthermore, products using these adhesives, such as furniture and houses, emit residual formaldehyde, which is not good for environmental health.

In addition, there are adhesives for plywood that are not related to formaldehyde, such as protein-based, vinyl acetate-based, rubber-based latex, and polyvinyl alcohol-based adhesives, but these have poor water resistance and are not very practical. I can't say that.

However, adhesive compositions in which one or a mixture of the above substances is used in a-plying with isocyanate for the purpose of improving water resistance are known, but in general, the use of isocyanate is used only after mixing It takes a relatively short time and may have an adverse effect on workability, adhesive properties, etc.

Although it is a well-known fact that water resistance is greatly improved by the introduction of incyanate, problems remain in terms of improving heat resistance.

The present inventors have made a copolymer of a water-soluble polymer and/or an aqueous dispersion of a polymer and a self-emulsifying polyurethane amino resin, and/or an incyanurate modified product of the copolymer as the main component, In systems that use additives to satisfy viscosity, dispersibility, stability, etc., the pot life is longer than that of a water-based adhesive composition that uses incyanate, making it possible to use it in a stable state. At the same time, we have discovered that not only water resistance but also heat resistance is greatly improved, and we have arrived at the present invention.

That is, the present invention comprises (1) a water-soluble polymer and/or an aqueous dispersion of a polymer, (2) an alkoxypolyalkylene glycol having a molecular weight of 250 to 4,000, and an organic polyisocyanate having a terminal group which is a reaction product. A self-emulsifying polyurethane amino resin copolymer (hereinafter referred to as copolymer) consisting of an incyanate group prepolymer (hereinafter referred to as prepolymer) and an amino-formaldehyde resin etherified with alcohol, and/or The present invention relates to an adhesive composition comprising a modified incyanurate and, if necessary, an additive.

Water-soluble polymers that can be used in the present invention include polyvinyl alcohol, water-soluble ethylene vinyl acetate polymer, polyethylene oxide, water-soluble acrylic resin, water-soluble epoxy resin,
Examples include water-soluble cellulose derivatives, water-soluble polyesters, and water-soluble lignin derivatives.

The aqueous polymer dispersion that can be used in the present invention includes all so-called latex emulsions. For example, styrene-butadiene copolymer latex, acrylonitrile-butadiene copolymer latex,
Rubber latex such as methyl meth 7 acrylate-butadiene copolymer latex, RGI prene latex, polybutane latex, polyacrylic acid ester latex, polyvinylidene chloride latex, polybutadiene latex, or carboxyl-modified versions of these latexes. Further examples include polyvinyl chloride emulsion, urethane acrylic emulsion, silicone acrylic emulsion, vinyl acetate acrylic emulsion, urethane emulsion, and acrylic emulsion.

It is known that an incyanate compound is used for the purpose of imparting water resistance to the water-soluble polymer and/or an aqueous dispersion of the polymer, but in the present invention, not only the water resistance but also the adhesive composition A major feature of this product is that it has solved the IW problems that had remained in this type of adhesive composition until now, such as extending the pot life of the product and imparting heat resistance.

Examples of the organic polyinsyanates that can be used in the synthesis of the prepolymer in the present invention include tetramethylene diysifnate, hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, inhorn diisocyanate, 414' methylene bis(cyclohexyl isocyanate), xylylene diisocyanate, and xylylene diisocyanate. cyanate,
Tolylene diisocyanate, diphenylmethane diincyanate.

Examples include polyphenylmethane polyinsyanate (hereinafter referred to as Borinlic MDI) chopsticks and these similar compounds alone or in a mixture of two or more.

Also useful is an organic polyisocyanate prepolymer obtained by reacting the organic polyisocyanate with a polyol having active hydrogen in an excess of incyanate.

The molecular weight of the alkoxy polyalkylene glycol constituting the prepolymer that can be used in the present invention is 250 to 400.
A value in the range of 0 is used, particularly preferably 600 to 600 per sentence.
It is of 2000 axis times.

After dispersion in water, this prepolymer forms a polyurea protective film on the surface of the prepolymer particles, maintains a state capable of suppressing the reaction between the incyanate groups of the prepolymer and water, and produces a stabilized internate emulsion. It is thought that it can be obtained.

The general formula of the alkoxypolyalkylene glycol that can be used in the present invention is represented by Rt0- (R,O)n-H,
Here, R1 is an alkyl group Jk and Rt is an alkylene group, and it is thought that this alkoxy group as a whole acts like a nonionic surfactant and exhibits self-emulsifying characteristics. R1 may also be an unsaturated hydrocarbon, such as ethylene,
Acetylene type etc. are used. In this case, the molecular weight that can be emulsified in water is 250 or more, but if the molecular weight is 4,000 or more, the emulsifying property in water is good, but the stability in water becomes poor, and at the same time, compounds with a molecular weight of 4,000 or more have high crystallinity. The storage stability of the prepolymer itself at low temperatures decreases, and turbidity occurs.1 Prepolymer 7 is generally produced by a known method in the absence of a solvent.
It is desirable to adjust the residual incyanate content to 20 to 30%. If it is less than 20%, the hydrophilicity in the interfacial layer of the emulsified particles becomes stronger than necessary during emulsification, resulting in poor stability. If it is more than 30%, the hydrophilicity in the interfacial layer is insufficient, making it difficult to form a stable emulsion. hard.

When reacting this prepolymer with 1jl of amino formaldehyde resin etherified with alcohol (hereinafter referred to as F74 no-formaldehyde resin) to obtain a copolymer, the reaction ratio between the prepolymer and the 7-mino formaldehyde resin is not particularly limited. However, the residual incyanate content must be 15-29% to make it emulsifiable with existing equipment.
It is preferable to do so as follows. If it is less than 15%, the viscosity of the resin will increase and the emulsifying properties will be poor, and if it is more than 29%, the characteristics of the copolymer will not be exhibited.

The active hydrogen concentration of the amino formaldehyde resin that can be used in the present invention is preferably 7.13 mm d 7 g or less. If the active hydrogen concentration exceeds this range, the viscosity of the product will increase, and the emulsifying property will not only decrease, but there is also a risk that the product itself will gel. Examples include melamine, urea, benzoguanamine, acetoguanamine, and 7-guanamine. Alcohols used for etherification include methyl,
Monohydric alcohols such as ethyl, propyl, isopropyl, butyl, and isobutyl are preferred.

By using the copolymer thus obtained in combination with the above-mentioned water-soluble polymer and/or polymer aqueous dispersion, the pot life can be extended, and an adhesive composition with excellent water resistance and heat resistance can be obtained. You can get the main components of things.

However, in order to use this adhesive composition in applications that require extremely high heat resistance, this requirement can be met by modifying the obtained copolymer with isocyanate.

When modifying the copolymer with an isocyanurate catalyst, the modification ratio is not particularly limited, but in order to make it emulsifiable with existing equipment, the residual incyanate content should be 10 to 10.
It is preferable to adjust the amount to 25%. If it is less than 10%, the viscosity of the resin increases, resulting in poor emulsifying properties, and at the same time, the effective incyanate content that contributes to crosslinking decreases, resulting in poor adhesiveness. Moreover, if it is more than 25%, the characteristics as a modified incyanurate product cannot be exhibited.

Examples of incyanurate catalysts that can be used in the present invention include potassium acetate, potassium octylate, N,N,N''-)lis(dimethylamirabrupyr)-3-hexatriazine, 2.
Known catalysts such as 4,6-tris(dimethyl7minomethyl)phenol can be used, and can also be used in combination with general urethanization catalysts.

After the denaturation, an acid catalyst is used as a reaction terminator in order to stably maintain the desired concentration of isocyanene-1 bacteria. In this case, the amount of the acid catalyst added is preferably at least an equivalent molar amount to the incyanurate catalyst.

Examples of the acid catalyst include p-) sulfonic acids such as luenesulfonic acid, xylene sulfonic acid, benzenesulfonic acid, methanesulfonic acid, alkylbenzenesulfonic acid, sinapthalene disulfonic acid, dinaphthalene monosulfonic acid, and aminophenolsulfonic acid; Methyl toluenesulfonate or phosphoric acids such as phosphoric acid, dimethyl phosphate, triethyl phosphate, triphenyl phosphate, 7-alkyl polyethylene ether phosphate, sulfanilic acid, nocrohexylsulfamic acid, naphthalene acid, etc., and similar The compounds may be used alone or in mixtures.

Additives may be used in the present invention as necessary. Examples of additives include stabilizers, thickeners, fillers, and the like.

Stabilizers include, for example, halogenated hydrocarbons such as chlorinated paraffin, ethers such as ethylene glycol motupyl ether, phthalates, oleates, adipates, azelaic esters, and stearic acid. Esters, esters such as benzoic acid esters, phosphoric acid esters, trimellitic acid esters, maleic acid esters, fumaric acid esters, etc., cyclic fullkylene carbonates, tertiary amines, nonionic Examples include surfactants. Examples of thickeners include wheat flour, carboquinomethyl cellulose,
Examples of fillers include celluloses such as hydroxyethyl cellulose and hydroxypropyl methyl cellulose, such as porcelain, talc, wood flour, clay, bentonite, starch, etc. The hardness of the resin content in the adhesive direction It is possible to adjust.

In the present invention, the order of addition of each component may be considered to be completely arbitrary, except for the copolymer or its incyanurate modified product. As a result, the viscosity and adhesive strength are hardly affected.5 The copolymer or its incyanurate modified product may be added as a water emulsion, or may be added directly in some cases.

According to the present invention, there are no emissions that pollute the environment, and the pot life is long, so it can be used in a stable state.
As a result, excellent applicability to the substrate and sufficient adhesive strength are obtained, and the molded product has excellent water resistance, heat resistance, and adhesive strength.

Although the present adhesive composition exhibits sufficient adhesive strength even when bonded at room temperature, it is also meaningful to perform appropriate heat treatment in order to improve workability, adhesion, water resistance, heat resistance, etc.

This adhesive composition is particularly suitable for plywood, secondary processing of plywood, and woodworking, but is also effective for particle board, corrugated poles, metal foil, paper, and textile processing. It is.

Next, the present invention will be explained in detail with reference to Examples, but the present invention is not limited to these Examples.

In Examples and Comparative Examples, parts and % indicate parts by weight and % by weight, respectively.

Example 1 Production of self-emulsifying polyurethane/amino resin copolymer 0
).

Temperature 1], polymeric MDI (Millione) MR-2 was placed in a 21 volume reactor equipped with a stirrer and an inert gas inlet tube.
00, manufactured by Nippon Polyurethane Industries), and then methoxypolyethylene glycol (MPG-081) was charged.
, Nippon Nyukazai Kogyo Co., Ltd.) was added, the temperature was raised, and the reaction was carried out for 3 hours while maintaining the temperature at 70°C. As a result, the NGO content was 2.
A 9.4% brown-transparent prepolymer was obtained. Another 70
Amino formaldehyde resin (MW
-3o, made by Sanphase Chemical) was added and reacted for 3 hours, resulting in NGO content of 27.1% and viscosity of 450Cp/2.
A brown transparent copolymer at 0° C. was obtained.

Example 2 Production of self-emulsifying polyurethane/amino resin copolymer (
2) In the manufacturing procedure of Example 1, 31 parts of MPG-025 (manufactured by Nippon Nyukazai Kogyo) was used instead of 130 parts of MPG-08, and amino formaldehyde resin (butylated melamine, When synthesized under the same conditions except that 120 parts (manufactured by Dainippon Ink Industries) was used, the NCO content was 260% and the viscosity was 550Cp/2oC.
A brownish transparent copolymer was obtained.

Example 3 Production of modified incyanurate.

A reactor equipped with the same equipment as in Example 1 was charged with iooo part of the copolymer obtained by the method in Example 1, and when the temperature was raised to 7°C, 2.4.6-tris(dimethyl7minomethyl) was added. ) 15 parts of phenol (DMP-30) was gradually added dropwise to modify the isone athlate for 2 hours while maintaining the temperature at 70°C. The mixture was added dropwise and the same temperature was maintained for an additional 2 hours to obtain an iso/americate modified copolymer with an NGO content of 25.7% and a viscosity of 3,000 Cp and a transparent brownish-brown copolymer. For confirmation, this product was subjected to infrared spectroscopic analysis, and extremely strong absorption of 1410□□□ was observed, demonstrating that the isonoanule ring had been sufficiently introduced.

Example 4 100 parts of 10% polyvinyl alcohol aqueous solution (C-17, manufactured by Shin-Etsu Chemical), acrylic emulsion (AE33)
1, manufactured by Nippon Synthetic Rubber Co., Ltd.), 10 parts of wheat flour, and 30 parts of clay were thoroughly stirred and mixed to obtain an aqueous emulsion. Copolymer 15 obtained in Example 1 was added to 937,100 parts of this emul.
When the mixture was stirred and mixed with a glass rod, it was easily dispersed. The pot life of this paste at 25° C. was 3 hours and 40 minutes. Furthermore, this paste liquid was used as an adhesive for sawing boards, and an adhesion test (according to JIS K6852) was conducted under the following conditions.

Adherent material Kava/Kaba (10%) Application amount 2752/rr? Pressure tightening 10'f/cj x 2 hours curing Over 3 days Normal adhesive strength 168 instant/d Wood breakage rate 60% Boiling repeated adhesive force 77KP/J Wood breakage rate 48% Heat resistant adhesive strength
135 parts M - Wood breakage rate 25% (100°C x 24 hours) 114 hours/d Wood breakage rate 20% (120°C x 24 hours) Example 5 In place of the copolymer used in Example 4, Example The same test as in Example 4 was conducted using the modified incyanurate obtained in 3. The pot life of this paste at 25°C was 3 hours and 30 minutes.

Normal adhesive strength 175 to 9/blind Wood breakage rate 55% Boiling repeated adhesive force 85Q/cj Wood breakage rate 30% Heat resistant adhesive strength 176 ): p/cd Wood breakage rate 53% (100℃ x
24 hours) 192 KP/cd Wood breakage rate 62% (120°C x 24 hours) Comparative Example 1 Polymeric M was used instead of the copolymer used in Example 4.
A test similar to that in Example 4 was conducted using a mixture of 12 parts of DI (Mi! I Onate M) e-200, manufactured by Nippon Polyurethane Industries) and 3 parts of dibutyl phthalate. The pot life of this paste at 25° C. was 45 minutes.

Preliminary adhesive strength 125kF/- Wood breakage rate 35% Boiling repeated adhesive force 55 to 9/cd Wood breakage rate 2 parts% Heat resistant adhesive strength 102 to 9ZclI Wood breakage rate 31% (100℃ x 2
4 hours) 73KP/cj Wood breakage rate 10% (120°C x 24 hours) Example 6 100 parts of a 10% polyvinyl alcohol aqueous solution (PA-20° manufactured by Shin-Etsu Chemical Co., Ltd.), 1 styrene-butadiene [combined latex (two balls) LX-430, manufactured by Nippon Zeon) 6
5 parts of charcoal, 20 parts of charcoal, and 15 parts of talc were thoroughly stirred and mixed to obtain an aqueous emulsion.

Copolymer 1 obtained in Example 2 was added to 100 parts of this emulsion.
When 5 parts were added and stirred and mixed with a glass rod, it was easily dispersed. The pot life of this paste at 25℃ is 3 hours15
It was a minute. Furthermore, this paste liquid was used as an adhesive for plywood, and an adhesion test (JASIII construction plywood and stone construction plywood) was conducted under the following conditions.

Adherent material Akawa 7 (1,7X) 3 ply coating amount
302 part size 2 Estimated 15 minutes (22℃, R, H, 38%) / Cold pressure
10 degrees / c + dX 15 minutes secondary deposition 20 minutes heat pressure 110℃ × 10 instant / cd Wood breakage rate: 54% Comparative Example 2 Instead of the copolymer used in Example 6, Borimeri
MDI (Millionaire) MR-20
0, Japan Polyurethane Industry 1! A test similar to Example 6 was conducted using a mixture of 12 parts of dibutyl phthalate and 3 parts of dibutyl phthalate. The pot life of this paste at 25℃ is 5
It was 0 minutes.

Normal adhesive strength 11.7KP/aJ Wood breakage rate 90% Boiling repeated adhesive strength 9.61Qp/-Wood breakage rate 34% Patent applicant Nippon Urethane Service Co., Ltd.

Claims (1)

Scope of Claims: A terminal product which is a reaction product of a water-soluble polymer and/or an aqueous dispersion of a polymer, a flufuxiboalkylene glycol having a molecular weight of 250 to 4,000, and an organic polyisocyanate. A prepolymer whose group is an isocyanate group,
and an amino-formaldehyde resin etherified with alcohol, a self-emulsifying polyurethane amino resin copolymer and/or an isocyanurate modified product of the copolymer, and optionally (3) an additive. Composition.