JP2000109782A - Aqueous composition and adhesive - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an aqueous composition excellent in adhesive strength and waterproof even after expending an accumulation time, and useful as an adhesive for a woody material by including a specific polymer, an aqueous emulsion, a specified compound and a water-holding agent. SOLUTION: This aqueous composition comprises (A) a vinyl alcoholic polymer preferably having >=50 mol% saponification degree and 100-8,000 polymerization degree, (B) an aqueous emulsion in the ratio of the solids of the components A to B regulated so as to be (99/1)-(5/95) (expressed in terms of weight), (C) 1-200 pts.wt. polyfunctional isocyanate compound (e.g. tolylene isocyanate) based on 100 pts.wt. blend of the components A with B (expressed in terms of weight), and (D) 0.1-20 wt.% water-holding agent (e.g. trehalose) based on the whole solid components in the composition. The component A is obtained by saponifying a polymer composed of vinyl ester-based monomer units. An aqueous emulsion obtained by a method for carrying out emulsification after the polymerization of the polymer, such as a polyurethane emulsion, or the like, is cited as the component B.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aqueous composition and an adhesive, and more particularly to an aqueous composition useful for various uses, particularly as an adhesive for wood materials.

[0002]

2. Description of the Related Art Adhesives containing a water-soluble polymer, an aqueous emulsion and an isocyanate compound as main components do not generate formalin unlike conventional amino-last adhesives and can be pressed at room temperature for a relatively short time. By itself, extremely high adhesive strength and water resistance can be obtained, so that it has been awarded as an adhesive for wood materials (for example, JP-A-48-94739 and JP-A-50-69139). Further, as a similar adhesive, an aqueous adhesive composition comprising a copolymer emulsion of a hydroxyl group-containing monomer such as allyl alcohol, 2-human peroxyethyl acrylate, N-methylolated acrylamide and phenyl acetate and a divalent isocyanate compound (JP-A-49-26346)
A water-resistant adhesive composition comprising a poly (vinyl acetate) emulsion using poly (vinyl alcohol) as a dispersant (protective colloid) and a polyvalent isocyanate compound (JP-A-3-33178) has been proposed.
Furthermore, it comprises an emulsion polymer stabilized with polyvinyl alcohol, wherein the emulsion polymer has a first stage producing a vinyl acetate polymer having a glass transition temperature in the range of 10 to 40 ° C, and a second stage having a 50 to 120 stage. Prepared by a two-step polymerization process comprising preparing a methyl methacrylate copolymer having a glass transition temperature of 10 ° C., wherein the ratio of vinyl acetate polymer to methyl methacrylate copolymer is 10: 1.
~ 10: 6 adhesives in the range have been reported (Japanese Unexamined Patent Publication No. 2-3)
02485).

However, with the expansion of the objects to be bonded,
In some cases, there is a need to further improve the adhesive performance level or hunt-linkability of the current adhesive. Specifically, after the adhesive is applied to the adherend, if the deposition time is taken, the adhesive dries, which may cause a problem in workability and adhesive performance such as the lack of adhesive strength.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems of the prior art and to provide an adhesive having good hunting and linking properties which is excellent in adhesive strength and water resistance even when deposition time is taken. It is intended for.

[0005]

Means for Solving the Problems The present inventors have conducted intensive studies on the above-mentioned objects and found that (A) a phenolic alcohol polymer, (B) an aqueous emulsion, (C) a polyvalent isocyanate compound and
It has been found that an aqueous composition comprising (D) a water retention agent and having a content of (D) of 0.1 to 10% by weight based on the total solid content is suitable for the above-mentioned purpose, and completes the present invention. Reached.

[0006] The present invention also provides an adhesive comprising the above aqueous composition. Further, the present invention also provides a wood-based product obtained by bonding with the above-mentioned adhesive.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The vinyl alcohol-based polymer constituting the aqueous composition of the present invention can be obtained by saponifying a polymer comprising a vinyl ester-based monomer unit. Examples of the phenyl ester-based monomer include vinyl acetate formate, acetic acid vinyl acetate, acetic acid vinyl acetate, acetic acid vinyl acetate, and the like. Usually, acetic acid vinyl acetate is used.

The vinyl alcohol polymer of the present invention may be a copolymer of an ethylenically unsaturated monomer as long as the effects of the present invention are not impaired. Examples of such ethylenically unsaturated monomers include, for example, ethylene, propylene, isophthalene, acrylic acid, methacrylic acid, (anhydride) phthalic acid, (anhydride) maleic acid, (anhydride) itaconic acid, acrylonitrile, methacrylonitrile. , Acrylamide, methacrylamide, trimethyl- (3-acrylamito-3-dimethylpropyl) -ammonium chloride, acrylamito-2-methylfluorophenylsulfonic acid and its sodium salt, ethyl phenyl ether, butyl phenyl ether, N-phenyl nitrolithone, phenyl chlorinated chloride, odor Examples thereof include vinyl chloride, vinyl fluoride, vinyl chloride, polyvinyl fluoride, tetrafluoroethylene, sodium vinyl sulfonate and sodium allyl sulfonate. Further, in the presence of a thiol compound such as thiolacetic acid or mercaptofluoropionic acid, a terminal-modified vinyl alcohol-based polymer obtained by polymerizing a vinyl ester-based monomer such as vinyl acetate and saponifying the same may be used. it can.

The degree of saponification of the benzyl alcohol-based polymer is not particularly limited, but is preferably at least 50 mol%, more preferably at least 80 mol%, even more preferably at least 85 mol%. The degree of polymerization of the vinyl alcohol polymer is not particularly limited, but is preferably in the range of 100 to 8000, and more preferably 200 to 2,000.

[0010] The aqueous emulsion constituting the aqueous composition of the present invention may be a known anionic, cationic, amphoteric or amphoteric dispersant.
Radical polymerizable ethylenically unsaturated monomers and diene-based polymers in aqueous solutions containing one or more water-soluble polymers (protected colloids) such as nonionic low molecular surfactants, various polyvinyl alcohols, and human peroxyethyl cellulose. Emulsion polymerization type aqueous emulsions obtained by emulsion polymerization of monomers and aqueous emulsions obtained by post-emulsification methods of polymers represented by polyurethane emulsions are used alone or in combination of two or more.

The ethylenically unsaturated monomers constituting the emulsion polymerization type aqueous emulsion dispersoid of the present invention include olefins such as ethylene, propylene and isophthalene, phenyl chloride, divinyl chloride, phenyl fluoride, phenyl fluoride and the like. Halogenated olefins, vinyl formate, vinyl acetate, vinyl propionate, vinyl acetate, vinyl phosphate, etc., vinyl esters, acrylic acid, methyl acrylate, ethyl acrylate, acrylic acid
n-propyl, i-propyl acrylate, n-butyl acrylate, i-butyl acrylate, t-butyl acrylate, 2-ethylhexyl acrylate, tosyl acrylate, octadecyl acrylate, human oxypropyl trimethyl ammonium chlorite, etc. Acrylates, methacrylic acid, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, i-propyl methacrylate, n-butyl methacrylate, i-butyl methacrylate, t-butyl methacrylate, methacrylic acid 2 -Methacrylates such as ethylhexyl, decethyl methacrylate, octatecil methacrylate, and human methoxy propyl trimethyl ammonium chlorite; acrylamide; methacrylic acid DOO Bu, N- methylol acrylamide preparative Bu, N, N- di-methyl acrylamide preparative Bu, Akuriruamito Bu 2 Mechirufu ° Ropa Nsuruhon acid and Akuriruamito Bu of its sodium salt, trimethyl - (3-Akuriruamito Bu-3-di Mechirufu ° propyl) - ammonium chlorite Bu,
Nitriles such as 3-acrylamitofluorotrimethylammonium chlorite, 3-methacrylamitofluorotrimethylammonium chlorite, N-methylacrylamito, N-ethylacrylamito, cyanone acrylamito, acrylonitrile, methacrylonitrile,
Allyl compounds such as allyl acetate and allyl chloride, styrene, α-methylstyrene, P
-Methylstyrene sulfonic acid and its styrene-based monomers such as sodium and potassium salts, and other N-vinyl perylene, and the like. Examples of the diene-based monomer include phthalene, isophenylene, and chlorophenyl.

In carrying out the emulsion polymerization for obtaining the aqueous emulsion of the present invention, the above-mentioned monomer is temporarily or continuously added in the presence of water, the above-mentioned dispersant and the polymerization initiator, A usual emulsion polymerization method such as heating and stirring can be performed, and a method in which a monomer is previously mixed and emulsified with a dispersant aqueous solution can be continuously added.

The amount of the dispersant used in the present invention is as follows:
Although not particularly limited, usually 0.2 to 100 parts by weight of the monomer.
It is 50 parts by weight, preferably 0.5 to 20 parts by weight. The dispersant
If the amount is less than 0.2 parts by weight, the polymerization stability decreases, and
If the amount exceeds the limit, the viscosity becomes too high.

The polymerization initiator is not particularly restricted but includes, for example, potassium persulfate, sodium persulfate, ammonium persulfate, hydrogen peroxide, 2,2′-asbestos (2-amisinofuropropane) dihydrochloride, Cumene height peroxide, benzoyl peroxide, isofluorobenzene peroxide, and the like are used alone or in a retox system used in combination with a reducing agent such as sodium bisulfite, tartaric acid, L-ascorbic acid, formaldehyde sodium sodium sulfoxylate, and ferrous sulfate. .

The polyvalent isocyanate compound (C) constituting the aqueous composition of the present invention has two or more isocyanate groups in the molecule. Examples thereof include tolylenediisocyanate (TDI);
I; Trimethylol perfluoro-TDI (for example, product name: Desmodur L, manufactured by Bayer AG); triphenylmethane triisocyanate; methylene diphenyl phenyl isocyanate (MDI); hydrogenated MDI; polymerized MDI; hexamethylene diisocyanate; xylylene diisocyanate; 4,4-dicyclohexylmethane diisocyanate; isophorone diisocyanate, and the like. In addition, a free polymer having an isocyanate group at the terminal group may be used, which is pre-polymerized with an excess of polyisocyanate.

The water retention agent (D) constituting the aqueous composition of the present invention is not particularly limited as long as it has water retention, but starches, sugars and cellulose derivatives are preferred. Starches include raw starch, processed starch (degraded raw starch, starch derivative) and amylose. As raw starch, wheat, corn,
Examples include starch obtained from rice, potato, sweet potato, tadoka, coconut palm, and the like. In general, flour, corn starch, and potato starch are suitable. Examples of raw starch degradation products include oxidized starch and dextrin, and oxidized starch is suitable. Examples of the starch derivative include etherified starch, esterified starch, and cationized starch. Examples of sugars include glucose, fructose, isomerized sugar, monosaccharides such as xylose, maltose, lactose, sucrose, trehalose,
Disaccharides such as paratinose, reduced maltose, reduced paratinose, and reduced lactose; starch syrup, isomaltolico-sugar, fructo-olico-sugar, lactose, orico-sugar; soy-olico-sugar, xylo-olico-sugar; Examples include polysaccharides such as pectin, agar, konjac mannan, polydextrose, xanthan gum, and hyaluronic acid, and reducing sugars such as sorbitol. Examples of the cellulose derivative include carboxymethylcellulose and methylcellulose. Of these, oxidized starch, carboxymethylcellulose, methylcellulose, human peroxymethylcellulose, and trehalose are more preferably used.

The aqueous composition of the present invention comprises (C) a polyhydric isocyanate compound and (D) a water retention agent, with the above-mentioned main component mainly comprising (A) a vinyl alcohol polymer and (B) an aqueous emulsion. Do it. Here, the mixing ratio of the (A) vinyl alcohol-based polymer and the (B) aqueous emulsion in the main ingredient is (A) / (B) = 99/1 to solid content ratio.
It is preferably in the range of 5/95 (weight ratio), 95/5 to 10/9
A range of 0 is more preferred. The compounding of the polyvalent isocyanate compound (C) with respect to the main agent consisting of (A) and (B) may be appropriately selected according to various situations. However, a preferable compounding ratio is (C) 1 to 200 parts by weight, particularly preferably 5 to 100 parts by weight, per 100 parts by weight of the mixture of (A) and (B) (in terms of solid content). . If the amount of the polyvalent isocyanate compound is less than this range, the adhesive strength and water resistance will be low, and if it exceeds this range, the hot life after blending the polyvalent isocyanate will be short and not practical.

In the present invention, the content of the water retaining agent (D) is determined by the total solid content in the composition (if the composition contains components other than the components A, B, C and D, these components are also included). 0.1 ~
It is important that it be 20% by weight. If the water retention agent is less than this range, if the deposition time after applying the adhesive to the adherend is extended, sufficient adhesion will not be exhibited, and if it exceeds this range, the adhesion and water resistance will increase. May worsen. The preferred content of (D) is 1 to 15% by weight, and more preferably 1 to 10% by weight.

The aqueous composition of the present invention may contain, if necessary, a sort of alkionic acid, a copolymer of maleic anhydride and isophthalene, a copolymer of maleic anhydride and styrene, and a copolymer of maleic anhydride and methylvinyl ether. Water-soluble polymer compounds such as urea-formalin resin, urea-melamine-formalin resin, phenol-formalin resin, and other thermosetting resins generally used as adhesives can also be used as appropriate. Further, the aqueous composition of the present invention includes a filler such as clay, kaolin, talc, calcium carbonate, and wood flour; a bulking agent such as flour; a reaction accelerator such as boric acid and aluminum sulfate; a pigment such as titanium oxide; In addition, various additives such as a preservative and a rust inhibitor can be appropriately added as needed.

The aqueous adhesive of the present invention is used for bonding various adherends, and is particularly suitable for bonding wood.
The application amount may be appropriately selected according to various situations. Examples of the coating method include coating with a brush and coating with a roll. Drying after applying and pressing the adhesive may be drying by heating from room temperature to 200 ° C., but the adhesive of the present invention exhibits sufficient adhesive strength even when dried at room temperature.
The feature of the water-based adhesive of the present invention is that the time from application of the adhesive to the adherend to actual bonding is not deteriorated even when the deposition time is taken. The deposition time is preferably within 30 minutes. The drying time after applying the adhesive and pressing is preferably about 30 minutes to 5 hours. The pressure at the time of pressing is selected in the range of 5 to ²⁰ kg / cm2,
When the hard wood is the adherend, the pressure of the pressing is preferably higher, and when the soft wood is the adherend, the pressure is preferably high enough not to break the wood.

The wood-based product of the present invention is a wood-based product bonded with the above-mentioned adhesive, and includes plywood, laminated wood, furniture and the like. There are no particular restrictions on the type of wood in the wood-based product, and examples include kaha, tsuka, cedar, lauan, zelkova, hellhoek, comb, oak, and the like.

[0022]

The present invention will be described more specifically below with reference to examples and comparative examples. In Examples and Comparative Examples,
“Parts” and “%” are based on weight unless otherwise specified. Example 1 A vinyl alcohol-based polymer having a polymerization degree of 1700 (PVA-1: PVA-117 manufactured by Kuraray;
35 parts of a 15% aqueous solution having a polymerization degree of 1700 and a saponification degree of 98.5 mol%) were mixed with 65 parts of calcium carbonate, and the resulting mixture was mixed with an ethylene-vinyl acetate copolymer emulsion (OM-4200, solid content concentration 55%, manufactured by Kuraray) 100 To prepare a main ingredient. In addition, 30 parts of polymethylene polyphenylisocyanate (manufactured by Nippon Polyurethane Co., Ltd., trade name: Millionate MR-100), trehalose 10
(6% by weight based on the total solid content) to prepare a composition. Using this, a test was performed under the following conditions. The results are shown in Tables 1 and 2.

[Test conditions] Adhesion test An adhesion test was performed using the above composition under the following conditions. Substrate: Kaha / kaha (masa) water content 8% Coating amount: 250 g / m ² (both sides coated) Deposition time: 5 minutes Pressing conditions: 20 ° C, 24 hours, pressure 10 kg / cm ² (normal strength,
(Measurement of compressive shear adhesive strength according to JIS K-6852) Normal strength: Measured as it is after curing for 7 days at 20 ° C. Repeated boiling: After curing for 7 days at 20 ° C, place test specimen in boiling water After immersion for a period of time, the substrate was dried in air at 60 ° C. for 20 hours, further immersed in boiling water for 4 hours, immersed in water at room temperature until cooled, and subjected to the test in a wet state. Initial adhesiveness: After bonding, 10 kg / cm ² at 20 ° C and 10 kg / cm ²
Press for 1 minute and immediately measure compression shear adhesive strength

Example 2 A test was conducted in the same manner as in Example 1 except that oxidized starch was used instead of trehalose used in Example 1. The results are shown in Tables 1 and 2.

Example 3 A test was conducted in the same manner as in Example 1 except that carboxymethylcellulose was used instead of trehalose used in Example 1. The results are shown in Tables 1 and 2.

Comparative Example 1 A test was conducted in the same manner as in Example 1 except that the trehalose used in Example 1 was not used. The results are shown in Tables 1 and 2.

Example 4 35 parts of a 15% aqueous solution of a vinyl alcohol polymer (PVA-1) and calcium carbonate
Mix 65 parts and add styrene-phthalic acid copolymer emulsion
(DL-612, solid content concentration 50%, manufactured by Asahi Kasei) 100 parts was added to prepare a main agent. Then, 30 parts of polymethylene polyphenylisocyanate (manufactured by Nippon Polyurethane Co., Ltd., trade name: Millionate MR-100) and 10 parts of trehalose (6.2% by weight based on the total solid content) were added to prepare a composition.
Using this, a test was performed in the same manner as in Example 1. The results are shown in Tables 1 and 2.

Comparative Example 2 A test was conducted in the same manner as in Example 2 except that the trehalose used in Example 4 was not used. The results are shown in Tables 1 and 2.

Example 5 A vinyl alcohol-based polymer having a mercapto group at the end (polymerization degree: 500, saponification degree: 88.2 mol%, mercapto group content: 4.5) was placed in a glass polymerization vessel equipped with a stirrer, a nitrogen inlet, and a thermometer. × 10 ^-5 mol /
g-PVA) and 5 parts of ion-exchanged water were added and dissolved by heating. After cooling, the pH was adjusted to 3.0 with sulfuric acid, and the temperature was raised to 70 ° C. while performing nitrogen bubbling. With stirring at 150 rpm, 10 parts of methyl methacrylate and 10 parts of n-butyl acrylate were added, and 10 parts of a 1% aqueous solution of potassium persulfate was further added to initiate polymerization. One hour after the initiation of the polymerization, 40 parts of methyl methacrylate, 38 parts of n-butyl acrylate, and 2 parts of human peroxyethyl methacrylate were uniformly dropped over 2 hours. After completion of the dropwise addition, the temperature was raised to 80 ° C., and the mixture was left for 1 hour. Solids concentration 48.
5% of a methyl methacrylate-n-butyl acrylate-human peroxyethyl methacrylate copolymer emulsion (acrylic Em) was obtained. Vinyl alcohol polymer (PVA
35 parts of a 15% aqueous solution of -1) and 65 parts of calcium carbonate were mixed, and 100 parts of the above-mentioned acrylic Em was added thereto to prepare a main ingredient. Then, 30 parts of polymethylene polyphenylisocyanate (manufactured by Nippon Polyurethane Co., Ltd., trade name: Millionate MR-100) and 10 parts of trehalose (6.3% by weight based on the total solid content) were added to prepare a composition. Using this, a test was performed in the same manner as in Example 1. The results are shown in Tables 1 and 2.

Comparative Example 3 A test was conducted in the same manner as in Example 2 except that the trehalose used in Example 5 was not used. The results are shown in Tables 1 and 2.

Comparative Example 4 A test was conducted in the same manner as in Example 2 except that 50 parts of trehalose used in Example 5 (25.1% by weight based on the total solid content) was used.
The results are shown in Tables 1 and 2.

[0032]

[Table 1]

[0033]

[Table 2]

[0034]

The aqueous composition of the present invention is used for various applications including an adhesive. In particular, when used as an adhesive, the adhesive strength, water resistance, and initial adhesive strength are excellent even when the deposition time after applying the adhesive is taken. The water-based adhesive of the present invention can be applied to a case where various kinds of adherends are bonded, and can be suitably used particularly as an adhesive for wood materials. Also,
In addition to bonding wood materials, it can be used for bonding wood materials to paper, textiles, inorganic boards, films and the like. Further, the aqueous composition of the present invention can be effectively used as a base paint such as an inorganic binder, an inorganic plate, or a wooden panel by utilizing a film having excellent water resistance.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4J034 BA03 DA01 DB03 DB07 DP02 DP03 DP17 HA01 HA02 HA06 HA07 HA08 HB07 HC03 HC12 HC17 HC22 HC46 HC52 HC61 HC63 HC64 HC65 HC67 HC71 HC73 MA22 MA26 QC05 RA08 4J040 BA022 BA032 BA102 BA142 CA031 CA03 CA131 CA132 DA001 DA002 DB011 DB012 DC001 DC002 DD021 DD022 DE011 DE012 DF011 DF012 DF021 DF022 DF071 DF072 DF091 DF092 GA03 GA07 GA08 GA13 GA16 GA22 GA25 HA126 HC16 HD44 JA03 JB02 KA39 LA05 LA06 LA07 MA01 MB03 MA09

Claims (4)

[Claims] (1) a vinyl alcohol-based polymer, (B) an aqueous emulsion, (C) a polyvalent isocyanate compound,
(D) An aqueous composition comprising a water retention agent and having a content of (D) of 0.1 to 20% by weight based on the total solid content. 2. The aqueous composition according to claim 1, wherein (D) the water retention agent is at least one selected from starches, sugars and cellulose derivatives. 3. An aqueous adhesive comprising the composition according to claim 1. 4. A wood-based product obtained by using the aqueous adhesive according to claim 3.