JP2003105301A - Adhesive composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an adhesive composition having high adhesion strength, excellent durability, waterproof property, hot water resistant adhesive property, etc., having a long usable time to improve working property and also being a low formaldehyde diffusion type. SOLUTION: This adhesive composition contains (A) a synthetic resin emulsion obtained by performing an emulsion polymerization of a radical- polymerizable unsaturated monomer containing at least 1 kind of a primary hydroxy group-containing ethylenically unsaturated monomer as an essential component by using a polysaccharide as a protective colloid, and (B) a water soluble resol type phenol resin, and containing 5-120 pts.wt. solid portion of the (B) component based on 100 pts.wt. solid portion of the (A) component.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an adhesive composition, and more particularly, to an adhesive composition having high strength and excellent workability and reduced formaldehyde.

[0002]

2. Description of the Related Art In the conventional plywood market, plywood is made by laminating and bonding veneer mainly made of hardwood, and the adhesive is an amino resin adhesive such as melamine-formaldehyde resin, urea-formaldehyde resin. Agents are mainly used. In addition, vinyl acetate resin-based resins and resin compositions obtained by modifying vinyl acetate resin are also used as adhesives, for the purpose of partially reducing the formaldehyde or reducing the formaldehyde. However, due to the shortage of hardwood resources in recent years, it has become difficult to obtain them, and the ratio of plywood made from softwood is increasing year by year. Since softwood contains a large amount of tar components, these adhesives are extremely insufficient in terms of water resistance, hot water adhesiveness, durability, stability, etc., and severe boiling water resistance is required for plywood. It did not pass the JAS special standards. In addition, for JAS special standards, phenol resin adhesives have generally been used, but phenol resin adhesives are inferior in curability to amino resin adhesives, and heat generated during the production of plywood When pressing, high temperature and long time are required, which causes a significant decrease in workability and productivity, and also reduces the thickness of the product after pressing, causing surface deterioration and reducing the commercial value. There is.

Also, health problems due to indoor pollution of formaldehyde, that is, the problem of sick house syndrome has been highlighted, and F _C0 (formaldehyde emission amount = 0.5
(mg / l or less) is required. However, with conventional amino resin adhesives and phenol resin adhesives,
It is generally performed to reduce the use molar ratio of formaldehyde in order to obtain a low formaldehyde emission type, but in this case, the stability of the adhesive is significantly reduced, and the adhesiveness, especially water resistance, There is a problem in that the hot water adhesion is extremely poor.

On the other hand, as a water-resistant adhesive agent containing no formaldehyde, an adhesive agent prepared by mixing an aqueous emulsion, an aqueous polymer and an isocyanate compound is widely used. There is a problem in workability in terms of viscosity increase over time, workability is short, and workability is particularly problematic in the summer. Therefore, as a structural adhesive that requires a high degree of adhesion, resorcinol resin, resorcinol-phenol copolymer resin,
Although water-based polymer-isocyanate adhesives are used, the ones that can sufficiently satisfy the adhesive strength and workability have not yet been developed. Moreover, these problems are not limited to adhesives for plywood and wood,
It has been pointed out in various adhesives such as decorative plywood, fiber board, etc., and an urgent solution has been desired.

[0005]

SUMMARY OF THE INVENTION Therefore, the object of the present invention is to have high adhesive strength, excellent durability, water resistance and hot water adhesiveness, long pot life, improved workability, and low workability. An object is to provide an adhesive composition that is a formaldehyde emission type.

[0006]

As a result of intensive studies, the present inventors were able to achieve the above object. That is, the present invention uses (A) a polysaccharide as a protective colloid, and emulsion-polymerizes a radically polymerizable unsaturated monomer containing at least one primary hydroxyl group-containing ethylenically unsaturated monomer as an essential component. A synthetic resin emulsion and (B) a water-soluble resol-type phenol resin are contained, and the solid content of the (B) component is 100% of the solid content of the (A) component.
The adhesive composition is contained in an amount of 5 to 120 parts by weight with respect to parts by weight.

Further, the present invention further comprises (C) an acidic curing agent (solid content) in an amount of 0.25 to 100 parts by weight of the adhesive composition.
The above-mentioned adhesive composition containing 10 parts by weight is provided.

The present invention also provides the above adhesive composition, wherein the primary hydroxyl group-containing ethylenically unsaturated monomer is contained in an amount of 0.5 to 20% by weight based on the total radically polymerizable unsaturated monomer. Is provided.

The present invention also provides the above adhesive composition, wherein the polysaccharide is contained in an amount of 0.1 to 20 parts by weight with respect to 100 parts by weight of all radically polymerizable unsaturated monomers. is there.

The present invention also uses a polysaccharide as a protective colloid, and emulsion-polymerizes a radically polymerizable unsaturated monomer containing at least one primary hydroxyl group-containing ethylenically unsaturated monomer as an essential component, A) A synthetic resin emulsion is prepared, and the solid content of the synthetic resin emulsion (A) is 100%.
The present invention provides a method for producing an adhesive composition, which comprises blending 5 to 120 parts by weight of (B) a water-soluble resol-type phenol resin as a solid content with respect to parts by weight.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The adhesive composition of the present invention will be described below. (A) Synthetic Resin Emulsion The synthetic resin emulsion (A) used in the adhesive composition of the present invention uses a polysaccharide as a protective colloid and contains at least one primary hydroxyl group-containing ethylenically unsaturated monomer as an essential component. It can be obtained by emulsion polymerization of a radically polymerizable unsaturated monomer containing as. Examples of the polysaccharides used in preparing the component (A) include gum arabic, gum agti, gum tragacanth and the like. These polysaccharides can serve as protective colloids. When a polysaccharide is used as a protective colloid, anionic, cationic, amphoteric, and nonionic surfactants used in ordinary emulsion polymerization, various polyvinyl alcohols, and water-soluble polymers other than polysaccharides such as hydroxyethyl cellulose are used. In comparison with the above, it is possible to obtain the synthetic resin emulsion (A) which is significantly excellent in the mixing stability with the water-soluble resol type phenolic resin (B) described below. When emulsion-polymerizing to prepare the component (A), the amount of the polysaccharide used as a protective colloid is 0.1 based on 100 parts by weight of all radical-polymerizable unsaturated monomers.
It can be up to 20 parts by weight, preferably 0.5 to 15 parts by weight. When the content of the polysaccharide is less than 0.1 part by weight, the stability of the obtained (A) synthetic resin emulsion is poor, and aggregation, gelation and sedimentation occur, and when it exceeds 20 parts by weight, finally. It is not preferable because the water resistance of the obtained adhesive composition is significantly lowered. Further, as a protective colloid, it is possible to use various polyvinyl alcohols, hydroxyethyl cellulose, etc. in combination with polysaccharides. In that case, the blending amount is (B) stability against miscibility with water-soluble resol type phenolic resin. From the perspective of polysaccharide 1
It is desirable that the amount is 100 parts by weight or less with respect to 00 parts by weight.

On the other hand, as the at least one primary hydroxyl group-containing ethylenically unsaturated monomer used for preparing the component (A), hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, Hydroxybutyl (meth) acrylate, glycerol (meth) acrylate, 2-hydroxy- (meth) acrylate
3-phenoxypropyl, N-methylol acrylamide, N-ethanol acrylamide, N-propanol acrylamide, N-methylol methacrylamide,
Vinylphenol and the like can be mentioned. These can be used alone or 2
Combinations of more than one type can be used. The content of the primary hydroxyl group-containing ethylenically unsaturated monomer in the component (A) is 0.5 to 20 with respect to the total radically polymerizable unsaturated monomer.
It can be wt%. If the content of the primary hydroxyl group-containing ethylenically unsaturated monomer is less than 0.5% by weight, the adhesive strength will be insufficient, and if it exceeds 20% by weight, the viscosity of the adhesive composition will be high. It is not preferable because it significantly impairs workability.

Further, other radically polymerizable unsaturated monomers are not particularly limited, but (meth)
Methyl acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, sec- (meth) acrylate Butyl, t-butyl (meth) acrylate, n-pentyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n-octyl (meth) acrylate, lauryl (meth) acrylate, (meth) acrylic acid Stearyl, cyclohexyl (meth) acrylate, (meth) acrylic acid 2
-Methoxyethyl, 2-ethoxyethyl (meth) acrylate, 2-methoxypropyl (meth) acrylate, 3-methoxypropyl (meth) acrylate, 2-methoxybutyl (meth) acrylate, (meth) acrylic acid 3 -Methoxybutyl, (meth) acrylic acid esters such as 4-methoxybutyl (meth) acrylate, and monomers copolymerizable therewith, such as acrylic acid, methacrylic acid,
Examples thereof include α, β-ethylenically unsaturated carboxylic acids such as crotonic acid and itaconic acid, and aromatic vinyl compounds such as styrene and vinylstyrene.

In the adhesive composition of the present invention, the synthetic resin emulsion (A) can be produced by a conventional emulsion polymerization method. In emulsion polymerization, a generally used polymerization initiator can be used. Specific examples thereof include water-soluble inorganic peroxides or persulfates such as hydrogen peroxide, potassium persulfate and ammonium persulfate, organic peroxides such as cumene hydroperoxide and benzoyl peroxide, and azo such as azobisisobutylnitrile. Compounds. The amount of the polymerization initiator used is 0.1 with respect to 100 parts by weight of all radically polymerizable unsaturated monomers.
˜2.0 parts by weight is preferred. Further, the polymerization initiator,
It is also commonly used in combination with a reducing agent such as tartaric acid, formic acid, oxalic acid, acidic sodium sulfite, and Rongalit. Further, the radical-polymerizable unsaturated monomer can be subjected to an emulsion polymerization reaction all at once or in a divided manner, or continuously by dropping. The temperature of emulsion polymerization is usually 60 to 9
It can be carried out at 0 ° C. Further, it is of course possible to use together a molecular weight modifier which is generally used in emulsion polymerization, or a film-forming auxiliary, which is often used in the case of synthetic resin emulsion, can be added as required.

(B) Water-Soluble Resol-Type Phenolic Resin (B) The water-soluble resol-type phenolic resin used in the adhesive composition of the present invention contains formaldehyde in an amount of 1.0 to 3.0 mol per mol of phenol. It can be obtained by reacting at a ratio of. Examples of the phenols include phenol, cresol, xylenol, resorcinol and the like. Among them, phenol and resorcinol are preferable. Also, two or more of these may be used in combination. At the time of the reaction, hydroxides of alkali (earth) metals such as sodium hydroxide, potassium hydroxide, barium hydroxide, and magnesium hydroxide, ammonia water, amines such as hexamethylenetetramine, and dimethylethanolamine are used as a catalyst during the reaction. 0.05 to 1 mol
It can be used in a proportion of 0.5 mol. The reaction is usually carried out at a temperature of 50 to 100 ° C., and the reaction is carried out so that the water solubility of the water-soluble resol-type phenol resin (B) does not fall below 50%. When the water solubility of the component (B) is less than 50%,
(A) Mixing stability with the synthetic resin emulsion is insufficient, which is not preferable. Further, other forms of phenolic resin such as powder, emulsion type, solvent diluted type and the like are not suitable for the present invention. The adhesive composition of the present invention,
It is considered that the presence of the water-soluble resol-type phenol resin (B) in the continuous phase in the adhesive composition imparts excellent adhesiveness and water resistance. The water solubility of the resin is preferably 50% or more. Moreover, it is speculated that the presence of the water-soluble resol-type phenolic resin (B) in the continuous phase dramatically improves the adhesiveness to difficult-to-adhere materials such as softwood.

Adhesive Composition In the preparation of the adhesive composition of the present invention, (A) the synthetic resin emulsion and (B) the water-soluble resol-type phenol resin are based on 100 parts by weight of the solid content of the component (A). It is preferable that the solid content of the component (B) is 5 to 120 parts by weight, more preferably 10 to 100 parts by weight. If the amount of the water-soluble resol-type phenolic resin (B) is less than 5 parts by weight, the water resistance of the mixed film of the adhesive composition is insufficient, and sufficient hot water adhesive strength cannot be imparted to the softwood.
Further, (B) the water-soluble resol-type phenol resin is 120
When it exceeds the weight part, the viscosity of the adhesive composition approaches the viscosity of the water-soluble resol-type phenol resin (B) itself, so that a sufficient initial adhesive force cannot be obtained.

(C) Acidic Curing Agent In addition, the adhesive composition of the present invention may be used in combination with (C) an acidic curing agent that enables the composition to be cured at room temperature. The (C) acidic curing agent used at that time is an acidic catalyst,
Although not particularly limited, strongly acidic inorganic acids such as hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid or benzenesulfonic acid, paratoluenesulfonic acid, xylenesulfonic acid, dodecylbenzenesulfonic acid, oxalic acid, formic acid, acetic acid, lactic acid. It is possible to use organic acids such as and the like, acid anhydrides such as maleic anhydride and phthalic anhydride, ammonium salts such as ammonium chloride, ammonium sulfate, ammonium nitrate, ammonium acetate and ammonium phosphate, etc., alone or in combination of two or more kinds. it can. The compounding amount of the (C) acidic curing agent is the adhesive composition solid content 1 containing the (A) synthetic resin emulsion and the (B) water-soluble resol-type phenol resin.
The solid content is preferably 0.25 to 10 parts by weight with respect to 00 parts by weight.

Further, the adhesive composition of the present invention may contain calcium carbonate, clay, kaolin, talc, if necessary.
Fillers such as wood flour, fillers such as wheat flour, pigments such as titanium oxide, or various additives such as preservatives and rust preventives can be appropriately added.

There are no particular restrictions on the coating method or bonding method when the adhesive composition of the present invention is used, and any conventional method may be used. it can. For example, it can be used in a pressing method or the like in which an adhesive composition is applied to an adhesive surface of wood or the like by brushing, and the adhesive surfaces are bonded and fixed by applying pressure. Further, a heating and pressing method is used as a method for drying the adhesive composition of the present invention, and when the above-mentioned (C) acidic curing agent is used in combination, sufficient adhesive strength can be obtained by room temperature pressing.

The adhesive composition of the present invention has excellent durability,
It is possible to provide water resistance and hot water adhesiveness and the like, there is little increase in viscosity after addition of a curing agent, and there is no foaming which is a problem with water-based polymer-isocyanate adhesives and the like. The workability is improved by extending the usage time. That is, the adhesive composition of the present invention can be used to produce structural plywood that passes the JAS special standards even with plywood using softwood veneer, and also requires high durability in laminated wood. Can be used to make structural laminated wood. Further, the adhesive composition of the present invention has a small amount of formaldehyde generation and can pass the JAS F _C0 standard.

Since the adhesive composition of the present invention has extremely great advantages and characteristics as described above, it can be expected to have a wide range of uses. In particular, it can be used not only for heat curing but also for room temperature curing, excellent strength and workability, and low formaldehyde emission type, so it can be used as an adhesive for wood, plywood, decorative plywood, fiberboard, fiber products, paper products, etc. It is useful.

[0022]

EXAMPLES The present invention will be described in more detail below with reference to examples and comparative examples, but the present invention is by no means limited to these examples. In the examples and comparative examples, “parts” and “%” are based on weight unless otherwise specified.

Example 1 (A) Synthesis of synthetic resin emulsion In a 1 liter separable flask equipped with a stirrer, thermometer, reflux condenser, dropping funnel, 250 parts of 20% aqueous solution of gum arabic and 200 parts of ion exchange water. And the inside of the reaction vessel was heated to 80 ° C. while feeding nitrogen gas. Thereafter, 25 parts of 2-hydroxyethyl acrylate, 255 parts of methyl methacrylate and 170 parts of butyl acrylate.
The monomer mixture liquid with the parts was added dropwise over 4 hours. Ion-exchanged water was added to 2 parts of ammonium persulfate to bring the total amount to 50 g.
The above aqueous solution was added dropwise at the same time as the above-mentioned monomer mixed liquid to carry out emulsion polymerization. At this time, the internal temperature of the flask was 80
The external temperature was controlled so as to be ~ 85 ° C. After completion of dropping, the mixture was kept at 80 to 85 ° C for 1 hour and then cooled to 30 ° C or lower to obtain a synthetic resin emulsion. The obtained synthetic resin emulsion had a solid content concentration (105 ° C-1 hour dry) of 49.5% and a viscosity (BH viscometer, 10 rpm, 23
C.) was 15,000 mPa.s.

(B) Synthesis of water-soluble resol type phenol resin In a 1 liter separable flask equipped with a stirrer, thermometer, reflux condenser, dropping funnel, 300 g of phenol and 3 g of phenol were added.
Charge 392 g of 7% formalin, then add 113 g of a 10% sodium hydroxide aqueous solution to bring the inside of the reaction vessel to 8
Keep at 0 ℃ and react until the water solubility becomes 250%. 3
The mixture was cooled to 0 ° C or lower to obtain a water-soluble resol type phenol resin. The obtained water-soluble resol-type phenol resin had a solid content concentration (135 ° C.-1 hour dry) of 50.2% and a viscosity (B-type viscometer, 25 ° C.) of 150 mPa · s.

An adhesive composition was obtained by mixing both components so that the water-soluble resol-type phenol resin has a solid content of 25 parts with respect to 100 parts of the solid content of the synthetic resin emulsion obtained above. 10 parts of flour was added to 100 parts of the composition and mixed, and the performance of the adhesive composition of Example 1 was evaluated.

Example 2 (A) Synthesis of Synthetic Resin Emulsion In a 1 liter separable flask equipped with a stirrer, thermometer, reflux condenser, dropping funnel, 250 parts of 20% aqueous solution of gum arabic and 200 parts of ion-exchanged water. And the inside of the reaction vessel was heated to 80 ° C. while feeding nitrogen gas. Thereafter, 25 parts of 2-hydroxyethyl acrylate, 255 parts of methyl methacrylate and 170 parts of butyl acrylate.
The monomer mixture liquid with the parts was added dropwise over 4 hours. Ion-exchanged water was added to 2 parts of ammonium persulfate to bring the total amount to 50 g.
The above aqueous solution was added dropwise at the same time as the above-mentioned monomer mixed liquid to carry out emulsion polymerization. At this time, the internal temperature of the flask was 80
The external temperature was controlled so as to be ~ 85 ° C. After completion of dropping, the mixture was kept at 80 to 85 ° C for 1 hour and then cooled to 30 ° C or lower to obtain a synthetic resin emulsion. The obtained synthetic resin emulsion had a solid content concentration (105 ° C-1 hour dry) of 49.5% and a viscosity (BH viscometer, 10 rpm, 23
C.) was 15,000 mPa.s.

(B) Synthesis of water-soluble resol type phenol resin In a 1 liter separable flask equipped with a stirrer, thermometer, reflux condenser, dropping funnel, 300 g of phenol and 3 g of phenol were added.
Charge 392 g of 7% formalin, then add 113 g of a 10% sodium hydroxide aqueous solution to bring the inside of the reaction vessel to 8
Keep at 0 ℃ and react until the water solubility becomes 250%. 3
The mixture was cooled to 0 ° C or lower to obtain a water-soluble resol type phenol resin. The obtained water-soluble resol-type phenol resin had a solid content concentration (135 ° C.-1 hour dry) of 50.2% and a viscosity (B-type viscometer, 25 ° C.) of 150 mPa · s.

An adhesive composition was obtained by mixing the synthetic resin emulsion obtained above with 100 parts of the solid content so that the solid content of the water-soluble resol-type phenol resin was 25 parts. The following formulation was applied to the composition. Adhesive composition / wheat flour = 100 parts / 10 parts as a main ingredient, and 5 parts of 50% aqueous solution of paratoluenesulfonic acid as an acidic curing agent was added to 100 parts of the main ingredient,
The mixture was thoroughly mixed and the performance of the adhesive composition of Example 2 was evaluated.

Example 3 Example 2 was repeated except that 100 parts of the solid content of the synthetic resin emulsion of the above Example 2 and 67 parts of the solid content of the water-soluble resol type phenol resin of the above Example 2 were mixed. The performance was evaluated as the adhesive composition of Example 3 in accordance with the above.

Example 4 Synthesis was carried out in the same manner as in Example 2 except that N-methylolacrylamide was used in place of 2-hydroxyethyl acrylate in the synthesis of the synthetic resin emulsion of Example 2 above. To obtain a synthetic resin emulsion. The obtained synthetic resin emulsion has a solid content concentration (dried at 105 ° C. for 1 hour) of 48.9.
%, Viscosity (BH type viscometer, 10 rpm, 23 ° C.) is 1
It was 2,000 mPa · s. All were carried out in accordance with Example 2 except that the above synthetic resin emulsion was used, and the performance of the adhesive composition of Example 4 was evaluated.

Comparative Example 1 An adhesive composition of Comparative Example 1 was prepared in the same manner as in Example 1 except that the synthetic resin emulsion of Example 1 was not used and the water-soluble resol-type phenol resin was not used. Performance evaluation was performed.

Comparative Example 2 The procedure of Example 2 was repeated except that 100 parts of the solid content of the synthetic resin emulsion of the above Example 2 and 400 parts of the solid content of the water-soluble resol type phenol resin of the above Example 1 were mixed. The adhesive composition of Comparative Example 2 was evaluated according to the performance.

Comparative Example 3 In the synthesis of the synthetic resin emulsion of the above Example 2, a monomer mixture solution of 25 parts of 2-hydroxyethyl acrylate, 255 parts of methyl methacrylate and 170 parts of butyl acrylate. Instead, it was synthesized in exactly the same manner as in Example 2 except that it was synthesized using a monomer mixed solution of 2-hydroxyethyl acrylate 0 part, methyl methacrylate 270 parts, and butyl acrylate 180 parts. A synthetic resin emulsion was obtained. Solid content concentration of the obtained synthetic resin emulsion (105 ° C-1 hour drying)
Is 49.5%, viscosity (BH viscometer, 10 rpm, 23
C.) was 10,000 mPa.s. Except for the above synthetic resin emulsion, the same procedure as in Example 2 was carried out.
The performance of the adhesive composition of Comparative Example 3 was evaluated.

Comparative Example 4 Instead of the water-soluble resol-type phenol resin of Example 2 above, 25 parts of a solid content of a phenol resin emulsion (SHONOL BRE-174 manufactured by Showa High Polymer Co., Ltd.) which is not a water-soluble phenol resin, The performance was evaluated as the adhesive composition of Comparative Example 4 according to Example 2 except that 100 parts of the solid content of the synthetic resin emulsion of Example 2 was mixed.

[Comparative Example 5] In the synthesis of the synthetic resin emulsion of Example 1 above, polyvinyl alcohol PVA M-205 was used instead of the 20% aqueous solution of gum arabic.
A synthetic resin emulsion was obtained in the same manner as in Example 1 except that a 20% aqueous solution of Kuraray (mercapto group-modified product) was used. The solid content concentration of the obtained synthetic resin emulsion (dried at 105 ° C. for 1 hour) was 49.6.
%, Viscosity (BH type viscometer, 10 rpm, 23 ° C.) is 1
It was 4,000 mPa · s. When 100 parts of the solid content of the synthetic resin emulsion and 20 parts of the solid content of the water-soluble resol-type phenol resin of Example 1 were mixed, the adhesive composition was aggregated.

<Tensile Shear Adhesion Test with Plywood> Using the adhesive compositions obtained in Examples and Comparative Examples, softwood veneer was adhered according to the following (1) Adhesion conditions, and the tensile shear adhesion of the obtained plywood The strength was measured. The (2) test method and (3) measurement method are described below. The measurement results are shown in Table 1. (1) Adhesion conditions / Base material: Larch veneer (thickness 2/3/2/3/2 mm
Cloth application 5 ply), water content 8% -Coating amount: 250 g / m ² (single-side coating) -Clamping: Example 1 and Comparative Example 1 were heated to 130 ° C,
8 kg / cm ² -20 minutes. Other than that, room temperature is 8 kg / c
m ² -20 minutes. (2) Test method Tensile shear test according to JIS K-6851 (3) Measurement method-Normal adhesive strength: Tensile shear adhesive strength of plywood is measured under standard conditions at 20 ° C and 65% RH-Steaming repeated adhesive strength (JAS) Special standards):
After soaking the plywood in water at room temperature (about 20 ° C) for 2 hours or more, steam at 130 ° C for 2 hours, then soak in running water at room temperature for 1 hour, steam at 130 ° C for 2 hours, and then plywood After immersing in water at room temperature until it cools, measure the tensile shear adhesive strength in the wet state

<Formaldehyde Emission Amount of Plywood> -Formaldehyde emission amount: One day after laminating: Measurement based on JAS ordinary plywood standard The measurement results are shown in Table 1.

[0038]

[Table 1]

<Block compression shear adhesion test> Using the adhesive compositions obtained in Examples and Comparative Examples, the following (1)
A test piece was prepared according to the adhesion conditions, and the compression shear adhesive strength was measured. This test is for laminated wood,
No data was collected for Example 1 because the adhesive strength was measured at room temperature. The (2) test method and (3) measurement method are described below. The measurement results are shown in Table 2. (1) bonding conditions Substrate: birch straight grain plate, water content 11% Coating weight: 250 g / m ² (two-sided coating) pressing: room temperature 10 kg / cm ² -30 minutes. (2) Test method Compressive shear test according to JIS K-6852 (3) Measuring method ・ Normal adhesive strength: Measure the compressive shear strength of a test piece under standard conditions at 20 ° C. and 65% RH ・ Repeated boiling adhesive strength: in boiling water After soaking the test piece for 4 hours in 60 ° C., it was dried at 60 ° C. for 20 hours, further soaked in boiling water for 4 hours, and the test piece was kept soaked until the temperature of the boiling water cooled to room temperature, and then the compressive shear strength was increased. Measurement / Initial adhesive strength: The compression shear strength was measured when the pressing time was 10 minutes under the (1) adhesive conditions in the above test piece preparation.

[0040]

[Table 2]

[0041]

EFFECTS OF THE INVENTION According to the present invention, it has a high adhesive strength, excellent durability, water resistance and hot water adhesiveness, has a long pot life, is improved in workability, and is of low formaldehyde emission type. An adhesive composition is provided.

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 4J040 BA142 DB061 DB071 DF011                       DF041 DF051 DF061 EB021                       EB052 GA05 HA086 HA216                       HA226 HA256 HA286 HB23                       HB26 HB47 HC01 HD13 JA03                       KA14 KA16 LA06 LA07 LA08                       QA01

Claims (5)

[Claims] 1. A polymer obtained by emulsion-polymerizing a radically polymerizable unsaturated monomer containing (A) a polysaccharide as a protective colloid and containing at least one primary hydroxyl group-containing ethylenically unsaturated monomer as an essential component. A synthetic resin emulsion and (B) a water-soluble resol-type phenol resin are contained, and the solid content of the (B) component is 100% of the solid content of the (A) component.
An adhesive composition characterized by being contained in a range of 5 to 120 parts by weight with respect to parts by weight. 2. The adhesive composition according to claim 1, further comprising (C) an acidic curing agent (solid content) in the range of 0.25 to 10 parts by weight with respect to 100 parts by weight of the adhesive composition. . 3. The primary hydroxyl group-containing ethylenically unsaturated monomer is 0.5 to 20 relative to the total radically polymerizable unsaturated monomer.
The adhesive composition according to claim 1, wherein the adhesive composition is contained in the range of wt%. 4. The adhesive composition according to claim 1, wherein the polysaccharide is contained in an amount of 0.1 to 20 parts by weight based on 100 parts by weight of all radically polymerizable unsaturated monomers. 5. A synthetic (A) is obtained by emulsion-polymerizing a radical-polymerizable unsaturated monomer containing at least one primary hydroxyl group-containing ethylenically unsaturated monomer as an essential component, using a polysaccharide as a protective colloid. A resin emulsion is prepared, and 5 to 120 parts by weight of (B) a water-soluble resol-type phenol resin is added as a solid content to 100 parts by weight of a solid content of the (A) synthetic resin emulsion. Method of manufacturing things.