JPH0578643A - Composition and adhesive - Google Patents

Abstract

PURPOSE:To obtain the subject composition consisting of a specific aqueous emulsion and a polyvalent isocyanate compound and having excellent initial adhesion, adhesive strength and water resistance, etc. CONSTITUTION:The objective composition obtained by blending (A) 100 pts.wt. aqueous emulsion containing a dispersoid obtained by blending (i) a vinyl ester based polymer existing in the center of the dispersoid with (ii) a copolymer existing in the periphery of the dispersoid and consisting of a primary hydroxy group-containing ethylene-based unsaturated monomer unit and one or more kinds of a methacrylic acid ester unit and an acrylic acid ester unit, having <50 deg.C glass transition temperature at a ratio of the components (i): (ii) of 9:1 to 1:9 and a dispersant consisting of polyvinyl alcohol with (B) a polyvalent isocyanate compound, a preferably of 20-100 pts.wt. and, as necessary, adding starch, sodium alginate, methyl cellulose, etc., thereto.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a composition and an adhesive, and more specifically, to various applications, particularly a composition useful as an adhesive, and an adhesive excellent in initial adhesiveness, adhesive strength, water resistance and the like formed from the composition. The present invention relates to an aqueous emulsion which is a main component of an adhesive and an adhesive, and a method for efficiently producing the same.

[0002]

2. Description of the Related Art Unlike conventional aminoplast-based adhesives, adhesives containing water-soluble polymers, aqueous emulsions and isocyanate-based compounds as main components do not generate formalin and are compressed at room temperature for a relatively short time. Since it is possible to obtain extremely high adhesive strength and water resistance by itself, it has been prized as an adhesive for wood (for example, JP-A-48-947).
39, 50-69139). As a similar adhesive, an aqueous adhesive composition comprising a copolymer emulsion of a hydroxyl group-containing monomer such as allyl alcohol, 2-hydroxyethyl acrylate, N-methylol acrylamide and vinyl acetate, and a divalent isocyanate compound. (JP-A-49-26346), a polyvinyl acetate emulsion containing polyvinyl alcohol as a dispersant (protective colloid), and a water-resistant adhesive composition comprising a polyvalent isocyanate compound (JP-A-3-33178).
Issue). Furthermore, it consists of an emulsion polymer stabilized with polyvinyl alcohol, the emulsion polymer producing a vinyl acetate copolymer having a glass transition temperature in the range of 10-40 ° C. in the first stage and 50-120 in the second stage. An adhesive produced by a two-step polymerization process consisting of producing a methyl methacrylate copolymer having a glass transition temperature of ℃, the ratio of vinyl acetate copolymer to methyl methacrylate copolymer being in the range of 10: 1 to 10: 6 is reported. (Japanese Patent Application Laid-Open No. 2-302485). Under such circumstances, in recent years, a JIS for wood adhesives composed of an aqueous polymer and an isocyanate compound has been established.

However, as the objects to be bonded expand,
In some cases, it is necessary to further improve the current adhesive performance level. Specifically, higher structural durability may be required as a structural adhesive, and further improvement in initial adhesiveness may be required in individual applications. In the latter case, polyvinyl alcohol (hereinafter, PVA
However, when an aqueous emulsion of a vinyl acetate-based resin is used as a dispersant, the initial adhesiveness is improved but the water resistance is not sufficient. In addition, although the conventional adhesives as described above exhibit some degree of performance, those having satisfactory performance in all of the initial adhesiveness, adhesive strength and water resistance have not yet been developed. is the current situation.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above problems in the prior art and to provide an adhesive having excellent adhesive strength and water resistance and good initial adhesiveness. Is.

[0005]

Means for Solving the Problems The inventors of the present invention have made extensive studies in view of the above-mentioned object, and as a result, (A) a vinyl ester polymer and at least one of a methacrylic acid ester unit and an acrylic acid ester unit. (Hereinafter, it may be referred to as a (meth) acrylic acid ester unit) and a dispersoid composed of a copolymer having a primary hydroxyl group-containing ethylenically unsaturated monomer unit and having a glass transition temperature of less than 50 ° C. Exists in the center of the dispersoid,
The copolymer is mainly present in the peripheral portion of the dispersoid, and the aqueous emulsion containing the dispersoid in which the weight ratio of the polymer and the copolymer is 9: 1 to 1: 9 and the dispersant composed of polyvinyl alcohol is It was found to be suitable for the intended purpose.

The present invention also provides a composition comprising the above-mentioned (A) aqueous emulsion and (B) a polyvalent isocyanate compound, as well as an adhesive comprising the composition. Further, the present invention also provides a wood product obtained by adhering with the above adhesive. Furthermore, the present invention, in the presence of a dispersant consisting of polyvinyl alcohol,
Emulsion polymerization of vinyl ester-based monomer to produce vinyl ester-based polymer, after which at least one of methacrylic acid ester and acrylic acid ester (hereinafter sometimes referred to as (meth) acrylic acid ester) and primary hydroxyl group Emulsion polymerization of the contained ethylenically unsaturated monomer to produce a copolymer of (meth) acrylic acid ester units and primary hydroxyl group-containing ethylenically unsaturated monomer units having a glass transition temperature of less than 50 ° C. The present invention also provides a method for producing the above-mentioned aqueous emulsion.

The aqueous emulsion of the present invention contains a dispersoid and a dispersant as described above. Here, the dispersoid is a vinyl ester polymer and a (meth) acrylic acid ester unit and a primary hydroxyl group-containing ethylenic monomer. It is an aggregate of one dispersoid composed of a copolymer composed of a saturated monomer unit and having a glass transition temperature of less than 50 ° C. The vinyl ester-based polymer may be various ones, but in general, vinyl acetate, vinyl propionate, vinyl pivalate, and vinyl ester of a tertiary carboxylic acid having 8 to 10 carbon atoms (for example, a product manufactured by Shell Chemical Co., Ltd. Name: Veova
10), vinyl stearate, further vinyl formate, vinyl valerate, vinyl caprate, vinyl laurate, vinyl benzoate and the like, which is a (co) polymer mainly composed of vinyl ester units.
Copolymers comprising 0% by weight or less of ethylene, vinyl chloride and other copolymerizable monomer units and a small amount of monomer units having functional groups such as carboxyl groups and amide groups are also included. The glass transition temperature (Tg) of this vinyl ester-based polymer is not particularly limited, but it is from -10 ° C to
It is preferably in the range of 40 ° C. If the Tg is less than -10 ° C or higher than 40 ° C, the adhesive strength may decrease when the aqueous emulsion is used as an adhesive.

Next, the copolymer is a copolymer comprising a (meth) acrylic acid ester unit and a primary hydroxyl group-containing ethylenically unsaturated monomer unit, and it is necessary that Tg is less than 50.degree. It is preferably 5 ° C or higher and lower than 50 ° C, more preferably 10 to 40 ° C. When Tg is less than 5 ° C, when this aqueous emulsion is used as an adhesive, the adhesive strength may decrease due to lack of cohesive force, and when it is 50 ° C or higher, the film-forming property decreases, As a result, the adhesive strength is reduced.

Further, the (meth) acrylic acid ester unit constituting the copolymer is a methacrylic acid ester unit or an acrylic acid ester unit, and among them, both units of the methacrylic acid ester unit and the acrylic acid ester unit are included. It is preferably contained. Here, the methacrylic acid ester unit is preferably a methacrylic acid ester unit (for example, methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate) unit having an alkyl group having 1 to 12 carbon atoms, particularly 1 to 4 carbon atoms. On the other hand, the acrylic acid ester unit is preferably an acrylic acid ester unit (for example, methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, decyl acrylate) having an alkyl group having 1 to 12 carbon atoms. Further, although there are various primary hydroxyl group-containing ethylenically unsaturated monomer units, preferred examples are hydroxyethyl acrylate, hydroxyethyl methacrylate, caprolactone-modified (meth) acrylic acid ester, and 3 to 3 carbon atoms. 10 α, β
-N-alkylolamides of ethylenically unsaturated carboxylic acids (N-methylol acrylamide, N-ethanol acrylamide, N-propanol acrylamide, N
-Methylol methacrylamide, N-ethanol methacrylamide, N-methanol maleamide and the like), and primary hydroxyl group-containing ethylenically unsaturated monomer units such as allyl alcohol. Each of these (meth) acrylic acid ester units or primary hydroxyl group-containing ethylenically unsaturated monomer units may be used alone or in combination of two or more.

When the Tg is in the range of less than 50 ° C., the above copolymer has (meth) acrylic acid ester units and 1
A copolymerizable monomer unit may be contained together with the primary hydroxyl group-containing ethylenically unsaturated monomer unit, for example, a styrene unit or a diene unit such as butadiene or isoprene. Further, it may contain a monomer unit having a functional group other than the primary hydroxyl group or a divinyl monomer unit such as ethylene glycol dimethacrylate. This copolymer is composed of a (meth) acrylic acid ester unit and a primary hydroxyl group-containing ethylenically unsaturated monomer unit as described above. The proportion of each of these structural units is not particularly limited as long as the Tg of the copolymer is in the range of less than 50 ° C., but usually, the (meth) acrylic acid ester units 85 to 99.8 are added to the total amount of the copolymer. % By weight, preferably 90
It may be selected in the range of up to 99.5% by weight. When both a methacrylic acid ester unit and an acrylic acid ester unit are used as the (meth) acrylic acid ester unit, the methacrylic acid ester unit is 20 to 70% by weight, preferably 30 to 65% by weight. 20-50% by weight, preferably 25-45% by weight
Select within the range. Further, the primary hydroxyl group-containing ethylenically unsaturated monomer unit is contained in an amount of 0.1 to 50% by weight, preferably 0.2.
˜15% by weight, more preferably 0.5 to 10% by weight. If the proportion of the primary hydroxyl group-containing ethylenically unsaturated monomer unit is too low, the water resistance of the resulting adhesive will not be sufficiently improved.

The dispersoid of the aqueous emulsion of the present invention is an aggregate of one dispersoid composed of a polymer and a copolymer, and the polymer is mainly present in the central part of the dispersoid,
The copolymer has a two-layer structure mainly present in the peripheral portion of the dispersoid. That is, the polymer is mainly (specifically 70% by weight or more, preferably 80% by weight or more, particularly preferably 90% by weight or more) in the central part of the dispersoid, and the copolymer is mainly (specifically 70% by weight or more, preferably 80% by weight or more, and particularly preferably 90% by weight or more). The shape of the polymer and the copolymer constituting the dispersoid is not necessarily spherical, but may be various shapes as shown in FIG. 1, for example. In addition, FIG. 1 is an enlarged schematic view of the structure of the dispersoid, in which 1 represents a polymer and 2 represents a copolymer. Further, such a two-layer structure of dispersoid can be confirmed by a transmission electron microscope. The weight ratio of the polymer to the copolymer in the dispersoid is 9: 1 to 1: 9, preferably 8: 2 to 2:
8 When the weight ratio of the polymer exceeds 90% by weight with respect to the total amount of the polymer and the copolymer, the water resistance of the obtained adhesive decreases, and conversely, when it is less than 10% by weight,
Emulsion stability is reduced.

The aqueous emulsion of the present invention contains the above dispersoid and a dispersant, and the dispersant is P
The one made of VA is used. Conventionally known PVA is used as the PVA, for example, PVA having a saponification degree of 80 to 99 mol% and a polymerization degree of 200 to 8000, and so-called modified PVA having a functional group introduced into the main chain, side chain or molecular end is also suitable. is there. Further, as the dispersant, a conventionally known emulsion stabilizer other than PVA can be used in combination as long as the initial adhesiveness and other properties are not impaired. The average particle size of the dispersoid of this aqueous emulsion is not particularly limited,
The thickness is preferably 0.5 to 2 μm, more preferably 0.8 to 1.5 μm. Further, the dispersoid concentration in this aqueous emulsion may be appropriately selected according to various situations, but is 40 to 6
0 wt% is preferable, and 45 to 55 wt% is more preferable. The dispersant concentration is also not particularly limited,
The amount is preferably 0.2 to 50 parts by weight, more preferably 1 to 10 parts by weight, based on 100 parts by weight of the dispersoid. Incidentally, the aqueous emulsion of the present invention, as described above, the dispersoid forms a specific two-layer structure, but if the two-layer structure is not formed here, or even if it has a two-layer structure, When the polymer is mainly present in the part and the copolymer is present in the central part, the stability of the aqueous emulsion is low and sufficient water resistance is not exhibited when used in the adhesive.

The aqueous emulsion of the present invention is one in which the dispersoid is dispersion-stabilized with a dispersant composed of PVA, and various aqueous emulsions can be added to the aqueous emulsion, if desired. As such an aqueous emulsion, a vinyl acetate emulsion,
Ethylene-vinyl acetate copolymer emulsion, polychloroprene emulsion, polybutadiene emulsion,
Examples thereof include styrene-butadiene copolymer emulsion, butadiene-acrylonitrile copolymer emulsion, butyl rubber emulsion, polyacrylic ester emulsion, polyvinyl chloride emulsion, polyvinylidene chloride emulsion and the like.

The composition of the present invention comprises the above-mentioned aqueous emulsion as the component (A) and a polyvalent isocyanate compound as the component (B). Here, the (B) polyvalent isocyanate compound has two or more isocyanate groups in the molecule, and for example, tolylene diisocyanate (TDI); hydrogenated TDI; trimethylolpropane-
TDI adduct (eg Bayer, trade name: Des
modurL); triphenylmethane triisocyanate; methylenebisdiphenylisocyanate (MD
I); hydrogenated MDI; polymerized MDI; hexamethylene diisocyanate; xylylene diisocyanate; 4,4-
Dicyclohexylmethane diisocyanate; isophorone diisocyanate and the like. In addition, a prepolymer obtained by polymerizing a polyol in advance with an excess of polyisocyanate may have an isocyanate group as an end group.

The composition of the present invention comprises (A) an aqueous emulsion as a main component and (B) a polyisocyanate compound mixed therein, wherein the mixing ratio of both components is various. It may be appropriately selected depending on the situation. However, the preferable mixing ratio is (A) with respect to 100 parts by weight (based on solid content) of the main component containing the aqueous emulsion as a main component,
(B) 10 to 150 parts by weight of a polyvalent isocyanate compound,
It is particularly preferably 20 to 100 parts by weight. The composition of the present invention contains PVA contained as a dispersant in the aqueous emulsion, but PVA can be additionally added if necessary. As the PVA in this case, a conventionally known one is used.

In the composition of the present invention, if necessary, starch, modified starch, oxidized starch, sodium alginate, carboxymethyl cellulose, methyl cellulose, hydroxymethyl cellulose, maleic anhydride-
Water-soluble polymer compounds such as isobutene copolymer, maleic anhydride-styrene copolymer, maleic anhydride-methyl vinyl ether copolymer, urea-formalin resin, urea-
Thermosetting resins generally used as adhesives, such as melamine-formalin resin and phenol-formalin resin, can be appropriately used. Further, the composition of the present invention includes fillers such as clay, kaolin, talc, calcium carbonate and wood flour, extenders such as wheat flour, reaction accelerators such as boric acid and aluminum sulfate, pigments such as titanium oxide and others. Various additives such as antiseptics and rust preventives can be appropriately added as needed.

The adhesive of the present invention is used for adhering various adherends, and is particularly suitable for adhering wood. Preferably 20 to 300 g / m ² as a coating amount of solid content basis, 30 to 200 g / m ² is more preferable. Examples of the coating method include brush coating and roll coating. Drying from room temperature to 200 after applying the adhesive
Although it may be dried by heating at ℃, the adhesive of the present invention exhibits sufficient adhesive force even when dried at room temperature. The adhesive of the present invention is characterized in that it has excellent initial adhesiveness and water-resistant adhesiveness in boiling water. The drying time after applying the adhesive is preferably about 30 minutes to 5 hours. It is preferable to dry the adhesive while it is pressed. The pressure at the time of pressing is selected in the range of 5 to ²⁰ kg / cm ² , and when the hard wood is the adherend, the higher the pressing pressure is, the softer wood is the adherend. In this case, it is preferable that the pressure be high enough not to destroy the wood.

The wood-based product of the present invention is a wood-based product adhered with the above-mentioned adhesive, and examples include laminated wood (plywood) and furniture. There are no particular restrictions on the type of wood in wood products, examples of which include hippo, hemlock,
Examples include cedar, lauan, and zelkova.

Various methods are conceivable for producing the above-mentioned aqueous emulsion of the present invention. Among them, the most efficient method for producing an aqueous emulsion of high quality is in the presence of a dispersant composed of PVA. , A first step of emulsion-polymerizing a vinyl ester-based monomer to produce a vinyl ester-based polymer, and then emulsion-polymerizing a (meth) acrylic acid ester and a primary hydroxyl group-containing ethylenically unsaturated monomer, A two-stage polymerization method comprising a second step of producing the copolymer around the formed polymer is preferred. In the first stage of this method, it is desirable to substantially complete the polymerization of the vinyl ester-based monomer, but it is possible to shift to the second stage polymerization at a polymerization conversion rate of about 70%. Further, in the first step and the second step, it is not always necessary to carry out the polymerization in the same polymerization reactor, and separately prepare an aqueous emulsion of a vinyl ester-based polymer in advance,
Before carrying out emulsion copolymerization of the (meth) acrylic acid ester and the primary hydroxyl group-containing ethylenically unsaturated monomer,
It can also be produced by the so-called seed polymerization technique of adding to the system. The initiator in this emulsion polymerization is not particularly limited, but for example, hydrogen peroxide, cumene hydroperoxide, t-butyl hydroperoxide, persulfate (potassium, sodium or ammonium salt), peracetic acid t- Water-soluble initiators such as oxidizing substances such as butyl and t-butyl perbenzoate and reducing substances such as Rongalit and l (el) -ascorbic acid are preferably used.

In the two-step polymerization method of the present invention, it is necessary to carry out the emulsion polymerization of the first step and the second step in the presence of the dispersant composed of PVA. When PVA is not used as a dispersant, when the obtained aqueous emulsion is used as an adhesive, the initial adhesiveness is poor and the object of the present invention cannot be achieved. The PVA used here is
It is the same as that described in the description of the aqueous emulsion of the present invention. The amount of PVA used is not particularly limited, but is 0.2 to 50% by weight, preferably 1 to 10% by weight, based on the total amount of the first stage polymer and the second stage copolymer. The range is. In addition, the PVA may be added in the entire amount in the initial charge, or a part thereof may be continuously or intermittently added to the polymerization system. Further, conventionally known emulsion stabilizers other than PVA can be used in combination as long as the initial adhesiveness and other properties are not impaired.

The vinyl ester-based monomer used in the first step of the two-step polymerization method of the present invention is a raw material for the above-mentioned vinyl ester-based polymer, and the kind thereof is the kind of this vinyl ester-based polymer. It should correspond to. Further, the (meth) acrylic acid ester and the primary hydroxyl group-containing ethylenically unsaturated monomer used in the second step are also the raw materials of the above-mentioned copolymer, and the types and the usage ratios are as follows. It should just correspond to the kind and composition of the copolymer. Furthermore, regarding the weight ratio of the vinyl ester polymer to be produced in the first step and the copolymer to be produced in the second step, the weight ratio of the polymer to the copolymer in the aqueous emulsion of the present invention described above It may be selected to correspond.

[0022]

[Adhesion conditions]

Substrate: Hippo / Hippo (Heat) 8% Water content: 250g / m ² (both sides coating) Deposition time: 1 minute Pressing condition: 20 ° C, 24 hours, pressure 10kg / cm ² (normal strength, Repeated boiling test piece only) [Measurement conditions] Measurement of compression shear adhesive strength according to JIS K-6852 Normal strength: measured at 20 ° C. for 7 days, then measured as it is. Repeated boiling: cured at 20 ° C. for 7 days, and then tested. After soaking in boiling water for 4 hours, it was dried in air at 60 ° C. for 20 hours, further immersed in boiling water for 4 hours, then soaked in water at room temperature until cooled, and subjected to the test in a wet state. Initial adhesion: 10 kg / cm ² at 20 ° C after bonding
Press for 10 minutes at the above pressure and immediately measure the compression shear adhesive strength

Example 2 (1) First stage The autoclave used in Example 1 was charged with an average degree of polymerization of 50.
0, 4 parts of partially saponified PVA having a saponification degree of 88 mol% is dissolved in 85 parts of ion-exchanged water, and 8 parts of vinyl acetate is added,
Under pressure of ethylene at 0 ° C. and 40 kg / cm ² , potassium persulfate and an aqueous solution of Rongalit were added to initiate polymerization.
The amount of the initiator added was set according to Example 1 so that the polymerization rate was appropriate (the same applies to the following Examples). Next, 36 parts of vinyl acetate was continuously added over 3 hours, and polymerization was performed until the concentration of vinyl acetate monomer in the polymerization system became 4%. (2) Second stage Next, MMA / 2-ethylhexyl acrylate (2
-EHA) / 2-hydroxyethyl acrylate (HE
A) = 28/15/2 (weight ratio) of a mixed monomer was continuously added over 2 hours for polymerization. In addition, 1 part of the same PVA used in the first step was made into a 15% aqueous solution and added during the polymerization. The obtained aqueous emulsion had a solid content concentration of 51.5% and a viscosity of 1010 mPas · s. Further, the Tg of the polymer of the first stage measured by DSC is 0.
C, Tg of the copolymer according to the second stage monomer composition is 1
It was 5 ° C. The ratio of the first stage polymer to the second stage copolymer was 55:45. (3) Adhesion test An adhesion test was performed in the same manner as in Example 1 using the above aqueous emulsion. The results are shown in Table 1.

Comparative Example 1 Instead of the PVA of Example 2, polyoxyethylene 40 mol addition nonyl phenyl ether (manufactured by Sanyo Kasei Co., Ltd., trade name:
The first-stage and second-stage (co) polymerizations were carried out as in Example 2, except that Nonipol 400) was used. As a result, the Tg of the polymer in the first stage was lowered to -3 ° C (this may be due to the plasticizing action of the nonionic activator). The resulting aqueous emulsion has a solid content concentration of 50.
The viscosity was 9% and the viscosity was 100 mPas · s. The ratio of the first stage polymer to the second stage copolymer was 55:45. An adhesion test was conducted in the same manner as in Example 1 using the above aqueous emulsion. The results are shown in Table 1.

Comparative Example 2 The average degree of polymerization of 170 was added to the autoclave used in Example 1.
4 parts of partially saponified PVA having a saponification degree of 88 mol% was dissolved by heating in 85 parts of ion-exchanged water, and then vinyl acetate (VA
c) / MMA / BA / HEMA = 60/21/16/3
20 parts of the mixed monomer (weight ratio) was added, and an aqueous potassium persulfate solution was added at 70 ° C. to initiate polymerization. The remaining 80 parts were continuously added over 3 hours to obtain PVA.
Although 1 part was continuously added as a 15% aqueous solution, the reaction was runaway at the end of the polymerization, and a large amount of aggregated mass was produced in the reactor.

Example 3 (1) First Step 3 parts of PVA (polymerization degree: 500, saponification degree: 88 mol%) was dissolved in 60 parts of ion-exchanged water, and VAc / Veova10 was added.
(Product name) = 29/21 (weight ratio) 10 of mixed monomers
Of the mixed monomer was added at 70 ° C. to start the polymerization, and 40 parts of the mixed monomer was continuously added over 2 hours to polymerize until the residual monomer concentration reached 0.5%. I went. (2) Second step Next, the VAc / obtained above was placed in another reactor in which a solution prepared by dissolving 2 parts of the PVA in 25 parts of ion-exchanged water was placed in advance.
The entire amount of Veova 10 copolymer aqueous emulsion was charged. Next, 10 parts of a mixed monomer of MMA / BA = 31/16 (weight ratio) was added, polymerization was started at 70 ° C. with potassium persulfate, and 40 parts of the mixed monomer and N- were added.
20% of 3 parts of methylol acrylamide (N-MAM)
The aqueous solution was continuously added over 2 hours. The obtained aqueous emulsion has a solid content concentration of 49.5% and a viscosity of 960 mPas.
It was s. The Tg of the polymer obtained in the first step is 1
The Tg of the copolymer obtained in the second stage was 5 ° C., and the ratio of the polymer in the first stage to the copolymer in the second stage was 5 ° C.
It was 0:50. An adhesion test was conducted in the same manner as in Example 1 using the above aqueous emulsion. The results are shown in Table 1.

Example 4 (1) First stage In a pressure-resistant autoclave, 3 parts of PVA used in Example 2 was dissolved in 85 parts of ion-exchanged water, and 18 parts of vinyl acetate and 18 parts of vinyl chloride were added and the mixture was heated at 60 ° C. 35 kg of ethylene
Pressed to cm ² . Polymerization was carried out by adding hydrogen peroxide solution and Rongalit aqueous solution. After 3 hours, the vinyl acetate concentration in the polymerization system reached 0.5%, so the system was taken out of the system.
The Tg of this polymer was 35 ° C. (2) Second stage Next, the above aqueous emulsion is transferred to a reactor under normal pressure,
MMA / styrene (St) / 2-EHA / HEMA = 1
1 of 8.5 / 18/22 / 1.5 (weight ratio) mixed monomer
0 part was added, and an aqueous potassium persulfate solution was added at 70 ° C. to initiate polymerization, and then 51.5 parts of the remaining amount of the mixed monomer was continuously added over 3 hours. Further, 2 parts of PVA was added as a 15% aqueous solution over 2 hours during the polymerization. The Tg of the copolymer produced in the second step was 15 ° C,
The obtained aqueous emulsion had a solid content concentration of 50.8% and a viscosity of 850 mPas · s. The ratio of the first stage polymer to the second stage copolymer was 40:60. An adhesion test was conducted in the same manner as in Example 1 using the above aqueous emulsion. The results are shown in Table 1.

Example 5 (1) First stage 3 parts of the same PVA used in Example 1 was replaced with ion-exchanged water 8
Dissolve in 5 parts, add 72 parts vinyl acetate, then 50
Ethylene was pressed in at 30 ° C. up to 30 kg / cm ² . Polymerization was carried out by adding hydrogen peroxide solution and Rongalit aqueous solution, and the vinyl acetate concentration during polymerization reached 2% in 2 hours. (2) Second stage Next, MMA / 2-EHA / HEA = 11.6 / 6.4 / 2.
Polymerization was continued by adding 0 (weight ratio) of the mixed monomer.
The obtained aqueous emulsion had a solid content concentration of 51.0% and a viscosity of 300 mPas · s. The Tg of the polymer obtained in the first step was 10 ° C. and the Tg of the copolymer produced in the second step was 15 ° C., and the ratio of the first step polymer to the second step copolymer was Was 80:20. An adhesion test was conducted in the same manner as in Example 1 using the above aqueous emulsion.
The results are shown in Table 1.

Comparative Example 3 (1) First Stage The same PVA used in Example 2 (average degree of polymerization: 500,
4 parts of saponification degree 88 mol%) is dissolved in 85 parts of ion-exchanged water, 74 parts of vinyl acetate is added, and 40 kg / c at 60 ° C.
Ethylene was pressed in up to m ² . When hydrogen peroxide solution and Rongalit solution were added and polymerized, the vinyl acetate concentration during the polymerization dropped to 1% in 3 hours. (2) Second stage Next, the total amount of mixed monomers of MMA / BA / HEA = 3.5 / 2.5 / 2.0 (weight ratio) was added, and the polymerization was further continued. At this time, 1 part of the same PVA as the above was added as a 10% aqueous solution during the polymerization. The resulting aqueous emulsion has a solid content concentration of 49.6% and a viscosity of 2500 mPas.
It was s. The Tg of the polymer obtained in the first step was 0 ° C., the Tg of the copolymer produced in the second step was 15 ° C., and the ratio of the first step polymer to the second step copolymer was Is 9
It was 2: 8. An adhesion test was conducted in the same manner as in Example 1 using the above aqueous emulsion. The results are shown in Table 1.

Comparative Example 4 (1) First stage 0.5 part of the same PVA used in Example 2 was dissolved in 20 parts of deionized water, 4 parts of vinyl acetate was added, and the mixture was mixed at 60 ° C. for 4 hours.
Polymerization was carried out by pressurizing ethylene to 0 kg / cm ² and adding a hydrogen peroxide solution and an aqueous solution of Rongalit, and the vinyl acetate concentration during the polymerization became 1% or less in 0.5 hours. (2) Second step Next, an aqueous solution prepared by previously dissolving 4.5 parts of PVA was added to 65 parts of ion-exchanged water, and MMA / BA / HEA = 52.
9 / 4.1 / 2 (weight ratio) of mixed monomers were copolymerized. Coarse particles were observed in the obtained aqueous emulsion, and when filtered off, the solid content concentration was 48.0% and the viscosity was 620 mPas.
・ It was s. The Tg of the polymer obtained in the first step
Was 0 ° C., the Tg of the copolymer formed in the second stage was 15 ° C., and the ratio of the polymer in the first stage to the copolymer in the second stage was 5:95. An adhesion test was conducted in the same manner as in Example 1 using the above aqueous emulsion. The results are shown in Table 1.

Comparative Example 5 (1) First Stage The same PVA used in Example 2 (3.0 parts) was dissolved in ion-exchanged water (85 parts), vinyl acetate (45 parts) was added, and the mixture was added at 60 ° C. to 40 kg / cm ^2. Ethylene was injected up to the pressure of. Then, hydrogen peroxide and an aqueous solution of Rongalit were added and polymerized, and the vinyl acetate concentration became 2% in 3 hours. (2) Second stage Next, MMA / BA / HEMA = 29.6 / 7.4 / 3
5 parts (by weight ratio) of the mixed monomer was added and polymerized at 70 ° C., and 38 parts of the mixed monomer was further added over 2 hours. At the same time, 2 parts of the PVA was added as a 15% aqueous solution. The resulting aqueous emulsion has a solid content of 50.2.
%, The viscosity was 1260 mPas · s. The Tg of the polymer obtained in the first step was 0 ° C., the Tg of the copolymer produced in the second step was 55 ° C., and the ratio of the polymer in the first step to the copolymer in the second step was Was 60:40. An adhesion test was conducted in the same manner as in Example 1 using the above aqueous emulsion. The results are shown in Table 1.

Comparative Example 6 MMA / 2-EHA = 29 / except that HEA was removed in the second stage by carrying out the first stage polymerization in the same manner as in Example 2.
(Co) polymerization was performed in the same manner as in Example 2 except that 16 (weight ratio) of the mixed monomer was added. The obtained aqueous emulsion has a solid content concentration of 48.9% and a viscosity of 1800 mPas.
It was s · s. The T of the polymer obtained in the first step
g is 0 ° C, Tg of the copolymer produced in the second stage is 14 ° C
And the ratio of first stage polymer to second stage copolymer was 55:45. An adhesion test was conducted in the same manner as in Example 1 using the above aqueous emulsion. The results are shown in Table 1.

Comparative Example 7 The average degree of polymerization of 170 was added to the autoclave used in Example 1.
After heating and dissolving 3 parts of partially saponified PVA having a saponification degree of 88 mol% with 85 parts of ion-exchanged water, MMA / BA / HE
MA = 21/16/3 (weight ratio) was added to 4 parts of a mixed monomer, and an aqueous potassium persulfate solution was added at 70 ° C. to initiate polymerization, and the remaining 36 parts of the monomer was continuously added over 3 hours. Was added. Then 60 parts vinyl acetate and PV
A2 part was continuously added as a 15% aqueous solution over 3 hours.
A large amount of agglomerate was formed in the reactor, and a good aqueous emulsion could not be obtained. The results are shown in Table 1.

[0034]

[Table 1]

[0035]

[Table 2]

[0036]

[Table 3]

[0037]

[Table 4]

* 1 Solid content of the final aqueous emulsion of 10
Amount based on 0 parts by weight (parts by weight) PVA 217: PVA having an average degree of polymerization of 1700 and a degree of saponification of 88 mol%,
Made by Kuraray Co., Ltd., PVA 205: PVA with an average degree of polymerization of 500, saponification degree of 88 mol%, made by Kuraray Co., Ltd. * 2 VAc: vinyl acetate, Et: ethylene, Veov
a: Veova10 (trade name, manufactured by Shell Kagaku), VC
l: vinyl chloride, MMA: methyl methacrylate, HE
MA: 2-hydroxyethyl methacrylate, HEA:
2-hydroxyethyl acrylate, N-MAM: N-
Methylol acrylamide, BA: butyl acrylate, 2-EHA: 2-ethylhexyl acrylate, S
t: Styrene * 3 () indicates the wood breaking rate. * 4 Composition cannot be prepared * 5 Coarse particles are generated in the dispersion

[0039]

The composition of the present invention is used for various purposes including adhesives. Particularly when used as an adhesive, the initial adhesive strength is excellent, and the adhesive strength and water resistance are dramatically improved. The adhesive of the present invention can be applied to bond various kinds of materials, and can be particularly preferably used for wood adhesives. Further, it can be used for bonding wood to each other as well as wood and paper, textiles, inorganic plates, films and the like. Further, the composition of the present invention can be effectively used for an inorganic binder, an inorganic plate, or a base paint for a wood panel by utilizing a film having excellent water resistance.

[Brief description of drawings]

FIG. 1 is an explanatory view schematically showing the structure of a dispersoid of an aqueous emulsion of the present invention.

[Explanation of symbols]

 1: Polymer 2: Copolymer

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification number Office reference number FI Technical display location C08L 33/06 LJB 7921-4J C09J 129/04 JCU 6904-4J 131/02 JCY 6904-4J 133 / 06 JDD 7242-4J (72) Inventor Tatsuaki Hattori 3-8-2 Nihonbashi, Chuo-ku, Tokyo Within Kuraray Co., Ltd.

Claims (5)

[Claims] 1. A glass transition temperature of less than 50 ° C. comprising (A) a vinyl ester polymer, at least one of a methacrylic acid ester unit and an acrylic acid ester unit, and a primary hydroxyl group-containing ethylenically unsaturated monomer unit. In the dispersoid composed of the copolymer, the polymer is mainly present in the central part of the dispersoid, the copolymer is mainly present in the peripheral part of the dispersoid, and the weight ratio of the polymer to the copolymer is 9: 1. A composition comprising (B) a polyisocyanate compound and an aqueous emulsion containing a dispersoid of 1 to 9 and a dispersant of polyvinyl alcohol. 2. An adhesive comprising the composition according to claim 1. 3. A wood product obtained by adhering with the adhesive according to claim 2. 4. A glass transition temperature of less than 50 ° C., which comprises (A) a vinyl ester polymer and at least one of a methacrylic acid ester unit and an acrylic acid ester unit and a primary hydroxyl group-containing ethylenically unsaturated monomer unit. In the dispersoid composed of the copolymer, the polymer is mainly present in the central part of the dispersoid, the copolymer is mainly present in the peripheral part of the dispersoid, and the weight ratio of the polymer to the copolymer is 9: 1. An aqueous emulsion containing a dispersoid of about 1: 9 and a dispersant of polyvinyl alcohol. 5. A vinyl ester polymer is produced by emulsion polymerizing a vinyl ester monomer in the presence of a dispersant composed of polyvinyl alcohol, and then at least one of methacrylic acid ester and acrylic acid ester and 1 Emulsion polymerization of a primary hydroxyl group-containing ethylenically unsaturated monomer to obtain a glass transition temperature of 50 ° C. comprising at least one of a methacrylic acid ester unit and an acrylic acid ester unit and a primary hydroxyl group-containing ethylenically unsaturated monomer unit. The method for producing an aqueous emulsion according to claim 4, wherein the copolymer is produced in an amount of less than 1.