TWI496792B - Modified polyvinyl alcohol for using as an emulsifying agent in production of polyvinyl acetate and its copolymer and method for producing polyvinyl acetate and its copolymer emulsion - Google Patents

Description

Modified polyethylene as an emulsifier for preparing polyvinyl acetate and its copolymer Alcohol and method for preparing polyvinyl acetate and copolymer emulsion thereof

The present invention relates to a modified polyvinyl alcohol (PVA) which can be used as an emulsifier in the manufacture of polyvinyl acetate and its copolymers, and a process for producing a latex having a vinyl acetate and a copolymer thereof, in particular Cross-linking PVA modified with C _1-4 alkoxy (meth) acrylamide as an emulsifier in polyvinyl acetate and its copolymers, and in the manufacture of vinyl acetate and its copolymer latex method.

Polyvinyl acetate resin (PVAc) is a thermoplastic polymer obtained by addition polymerization of a vinyl acetate monomer by radical polymerization. Although it was discovered very early, since the vinyl acetate monomer as a starting material itself is slightly water-soluble, and the polyvinyl acetate synthesized therefrom is insoluble in water, PVAc can be synthesized in a large amount and is Used, after the development of the emulsion polymerization process.

The hardening mechanism of the PVAc resin is different from that of the general condensation reaction resin. The PVAc emulsion has a relatively high degree of polymerization. During the hardening process, the molecular chain does not continue to polymerize, and only the moisture is removed to form a film. That is, after the coating, the PVAc emulsion is brought close to each other during the drying step of allowing moisture to escape, and when the water completely disappears, the particles and the particles are fused to each other to form a transparent film. Therefore, PVAc can be used without heating, and therefore it is widely used as a glue for wood and furniture, and because it is excellent in adhesion to cellulose and other materials, it has also been widely used in paper and fiber bonding or stiffening.

Polyvinyl acetate emulsion resin used in the use as a wood cement It is generally based on homopolymer and has very good adhesion to wood. However, since the polyvinyl acetate emulsion adhesive is relatively sensitive to moisture, the water resistance of the adhesive layer is insufficient and it needs to be improved by copolymerization to improve the strength and water resistance of the adhesive layer. Monomers which are industrially used for copolymerization with polyvinyl acetate are, for example, alkyl maleates such as dibutyl maleate; alkyl acrylates such as butyl acrylate. Although the above copolymer can improve certain physical properties of the homopolymer, the heat resistance is poor, the adhesive strength is weak, and the hardening time is long, resulting in poor workability.

Although the polyvinyl acetate resin can be formed into a grafting structure at a high reaction temperature and vigorous stirring to improve the mechanical properties of the resin polymer, it cannot increase its water resistance. In general, a polyvinyl acetate resin imparts a large amount of a functional group and a crosslinking group in a copolymerization reaction, and can be crosslinked to have a highly rigid cured product having a three-dimensional structure, thereby improving water resistance and heat resistance. Generally, N-methylol acrylamide is used to copolymerize self-crosslinking monomers, and acid salts are added and heat-hardened to improve water resistance (see Adhesive Handbook, 3rd edition, 1990). In addition, Armour, U.S. Patent No. 3,563,851, proposes to improve the water resistance of PVAc by copolymerizing vinyl acetate with an acrylate and then adding an acidic metal salt as a curing agent to heat harden.

Although the above-mentioned references and patent publications use the copolymerization method to improve physical properties, there are still disadvantages of insufficient adhesion or the need to add a hardener to heat and harden to enhance physical properties, which not only has a preservation problem, but also has a cumbersome effect on the two liquid types.

In the emulsion polymerization process of PVAc resin, a vinyl acetate monomer, an emulsifier (also referred to as an interface active agent or a protective colloid), and a polymerization initiator are coexisted in an aqueous solvent. When the polyvinyl acetate is produced by the emulsion polymerization method, polyvinyl alcohol (PVA) is usually used as an emulsifier, but the PVA structure contains a large amount of hydroxyl. Base, good hydrophilicity, easy to adsorb water molecules. Therefore, when the PVAc resin thus produced is applied to, for example, wood bonding, water molecules are easily infiltrated in the interface between wood and PVAc, causing the bonding layer to soften and thus lowering the bonding strength and cohesive strength.

Further, a cross-linked modified PVA having a N-methoxy acrylamide compound as a monomer and copolymerized with vinyl acetate to form a methoxy group after polymerization has been disclosed in Japanese Patent Laid-Open Publication No. SHO-58-76403. Polyvinyl acetate of methacrylamide, and then hydrolysis of acetate with a basic compound to form methoxymethyl acrylamide-containing polyvinyl alcohol having different degrees of saponification, using methoxymethyl propylene The guanamine provides PVA with suitable crosslinkability, thereby providing better water resistance after drying and for use on textiles.

In order to solve the above problems and based on the aforementioned patent documents, the inventors of the present invention have thought about the modification of the PVA structure which has been conventionally used as an emulsifier in the production of PVAc, and the introduction of a crosslinkable functional group in PVA has been found in a small amount. The modified PVA can function as an emulsifier in the emulsion polymerization of PVAc, and at the same time, the water resistance of the obtained PVAc emulsion can be improved, and thus the present invention has been completed.

One object of the present invention is to provide a polyvinyl alcohol (PVA) modified with C _1-4 alkoxy (meth) acrylamide, which has a degree of polymerization of 200 to 3000 and a degree of saponification of 80 mol%. 99.9% of the mole. The PVA modified by the C _1-4 alkoxy (meth) acrylamide of the present invention can be used as an emulsifier in the case of polyvinyl acetate and a copolymer resin thereof.

The C _1-4 alkoxy (meth) acrylamide modified PVA of the present invention can be initiated by polymerization of vinyl acetate monomer, C _1-4 alkoxy (meth) acrylamide After the radical polymerization in a solvent, a polyvinyl acetate containing a C _1-4 alkoxy (meth) acrylamide group is formed, followed by saponification with a base to obtain a C _{1-4 of the} present invention. Alkoxy (meth) acrylamide modified PVA.

The degree of polymerization of the C _1-4 alkoxy (meth) acrylamide modified PVA of the present invention is 200 to 3000, and the degree of saponification is from 80 mol% to 99.9 mol%. The PVA modified with C _1-4 alkoxy (meth) acrylamide in the present invention can be used as an emulsifier in the case of a polyvinyl acetate resin.

The C _1-4 alkoxy (meth) acrylamide modified PVA of the present invention can be initiated by polymerization of vinyl acetate monomer, C _1-4 alkoxy (meth) acrylamide After the radical polymerization in a solvent, a polyvinyl acetate containing a C _1-4 alkoxy (meth) acrylamide group is formed, followed by saponification with a base to obtain a C _{1-4 of the} present invention. Alkoxy (meth) acrylamide modified PVA.

Wherein, when the vinyl acetate monomer is 100 parts by weight, the amount of the C _1-4 alkoxy (meth) acrylamide is 0.5 to 15.0 parts by weight, and the amount of the polymerization initiator is such that radical polymerization can be initiated. The amount is not particularly limited, but is preferably from 100 to 1300 ppm, preferably from 150 to 1200 ppm. The solvent used for the polymerization reaction is an alcohol solvent, and for example, methanol, ethanol, isopropyl alcohol or the like can be used. The solvent to be used is preferably from 5 to 120 parts by weight, preferably from 5 to 110 parts by weight, based on 100 parts by weight of the vinyl acetate monomer, depending on the desired C _1-4 alkoxy (meth) acrylamide. The PVA viscosity was adjusted so that the viscosity of the 4% aqueous solution of the finally obtained modified PVA solution was in the range of 2.0 to 150 cps at 20 °C.

The temperature of the polymerization reaction depends on the solvent to be used, but is preferably from room temperature to the boiling point of the solvent to be used, more preferably from 30 to 90 ° C, most preferably from 40 to 70 ° C.

The polymerization initiator used in the polymerization reaction may be a polymerization initiator used in general radical polymerization, and the radical polymerization initiator is not particularly limited, and generally may be used. a nitrogen initiator or a peroxide polymerization initiator, the azo polymerization initiator is selected from the group consisting of azobisisobutyronitrile (AIBN), 1,1'-azobiscyclohexanecarbonitrile (ABCN), and even An azo polymerization initiator such as nitrogen-2,4-dimethylvaleronitrile or azobisisoheptanenitrile; the organic peroxide polymerization initiator comprises an organic peroxon compound, a peroxyester compound, and two a conventional radical polymerization initiator such as an alkyl peroxide, an alkyl hydrogen peroxide, a peroxydicarbonate or a ketone peroxide compound, wherein the organic peroxon compound is selected from benzammonium peroxide (BPO). , bismuth peroxide, laurel, bismuth peroxide, (2,4 dichlorobenzhydrazide), 3,5,5-trimethylhexyl peroxide, etc.; peroxyester compounds are selected from Butyl benzoate, tetraamyl benzoate, tert-butyl acetate, 3,5,5-trimethylhexanoate, butyl peroxylate, 3,5,5-trimethyl peroxide Third amyl hexanoate, tert-butyl isopropyl carbonate, tert-butyl 2-ethylhexyl carbonate, third pentyl isopropyl carbonate, 2-ethylhexyl peroxide Tert-butyl acid, Oxidation of diethyl triethyl ethanoate, tert-butyl peroxypivalate, third amyl peroxypivalate, tert-butyl peroxy neodecanoate, third pentoxide peroxynonanoate Ester, α-isopropylphenyl peroxy neodecanoate, triamyl peroxyacetate; dialkyl peroxide selected from 2,5-dimethyl-2,5-bis-(t-butyl Peroxy)-3-hexyne, dibutylbutyl peroxide, dipentyl peroxide, di-(2-tert-butylperoxyisopropyl)benzene, 2,5-dimethyl -2,5-bis-(t-butylperoxy)hexane, dicumyl peroxide; alkyl hydrogen peroxide is selected from the group consisting of tert-butyl hydroperoxide, third amyl hydroperoxide, and iso Propylbenzene hydroperoxide, dicumyl hydroperoxide, paraben hydrogen peroxide; peroxydicarbonate is selected from diisopropyl peroxydicarbonate, di(2-ethylhexyl)peroxydicarbonate ), bis(3-methoxybutyl) dicarbonate, bis(4-t-butylcyclohexyl)dicarbonate; the ketone peroxide compound is selected from methyl ethyl ketone peroxide Ethyl acetonitrile, cyclohexanone peroxide, but not limited to these.

In the above method, the base used for the saponification may be a general alkali metal hydroxide such as sodium hydroxide or potassium hydroxide. The alkali catalyst used in the present invention is selected from an inorganic base or an organic base compound which may be an alkali metal or an alkaline earth. a metal hydroxide or carbonic acid compound, including lithium hydroxide, sodium hydroxide, potassium hydroxide, calcium hydroxide, lithium carbonate, sodium carbonate, potassium carbonate, or calcium carbonate, etc., preferably sodium hydroxide; the organic base The compound may be an organic amine basic compound including ammonia water, tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, or a derivative thereof. Catalyst addition can be used once or twice. The concentration is not limited, but it is preferred to use a base having a concentration of 1 to 10% by weight. The degree of saponification of the C _1-4 alkoxy (meth) acrylamide modified PVA of the present invention is preferably from 55 mol% to 99.9 mol%, preferably from 75 mol% to 99 mol%. When the degree of saponification is less than 55 mol%, the formed PVA will not become water-soluble, which is not preferable from the viewpoint of producing aqueous PVAc.

A second object of the present invention relates to a process for producing a polyvinyl acetate and a copolymer emulsion thereof, which comprises using the C _1-4 alkoxy (meth) acrylamide modified PVA of the present invention as an emulsification The emulsion polymerization reaction is carried out in the presence of a radical polymerization initiator in a vinyl acetate monomer and/or other copolymerized monomer.

The PVA modified by C _1-4 alkoxy (meth) acrylamide in the present invention is used for the production of PVAc, and the amount of the monomer used for PVAc (ie, comprising vinyl acetate and other monomers) is 100. It is 0.5 to 30 parts by weight, preferably 2.5 to 15 parts by weight, based on parts by weight.

The polyvinyl acetate of the PVA modified by C _1-4 alkoxy (meth) acrylamide can be a homopolymer of vinyl acetate, and can also be vinyl acetate and other vinyl acetate. a copolymer of an ester copolymerized monomer, such as an unsaturated double bond-containing hydrocarbon compound or a halogenated hydrocarbon compound such as ethylene, propylene, butylene or vinyl chloride, (meth)acrylic acid, or (meth)acrylic acid C _1-8 Alkyl esters such as methyl (meth)acrylate, ethyl (meth)acrylate, isopropyl (meth)acrylate, isobutyl (meth)acrylate, isoamyl (meth)acrylate, (methyl) ) isohexyl acrylate, isoheptyl (meth) acrylate, isooctyl (meth) acrylate, isodecyl (meth) acrylate, etc., di-C _1-4 alkyl maleate such as maleic acid Dimethyl methacrylate, diethyl maleate, dipropyl maleate, dibutyl maleate, etc., (meth) acrylamide, C _1-4 alkoxy (A a propylene amide, a propylene sulfonium alkyl sulfonic acid compound and a salt thereof, an ethylene sulfonic acid and a salt thereof, a propylene sulfonic acid and a salt thereof, an alkyl vinyl ether, etc., and the comonomers may be used alone. Can also Combination of two or more. When two or more types are used in combination, the ratio between them is not particularly limited as long as it is within the range defined below with respect to the vinyl acetate monomer. When it is a copolymer of vinyl acetate and other monomers, the weight ratio of the vinyl acetate to other monomers is the other monomer: the weight ratio of vinyl acetate is (0~60): (100~40) The range is preferably (1~60): (99~40), and better (10~45): (90~55). When the ratio of other monomers is zero (0), it is expressed as a vinyl acetate homopolymer.

The radical polymerization initiator used in the method for producing a polyvinyl acetate emulsion of the present invention can be used as described above for producing a polyvinyl alcohol modified with a C _1-4 alkoxy (meth) acrylamide. Any free radical polymerization initiator.

When PVA modified with C _1-4 alkoxy (meth) acrylamide in the present invention is used for the production of PVAc, water resistance can be imparted to the obtained PVAc, presumably because of the C _1-4 alkoxy group contained therein. Since (meth) acrylamide has a function of crosslinking PVAc with each other, the degree of crosslinking of PVAc can be increased, and the water resistance can be improved.

The use of the C _1-4 alkoxy (meth) acrylamide modified PVA of the present invention for the production of PVAc, in addition to the desired vinyl acetate and other monomers, and the emulsifier of the present invention In addition to the PVA modified with C _1-4 alkoxy (meth) acrylamide, a crosslinking accelerator is preferably contained, and the crosslinking reaction can be further promoted to further improve the water resistance of the obtained PVAc. The use of the crosslinking accelerator is not essential, but when used, the amount is preferably from 0.1 to 20.0% by weight of all the monomers used in the manufacture of PVAc or its copolymer (ie, comprising vinyl acetate and other monomers). Good is 2.0~10.0% by weight. As the crosslinking accelerator, for example, AlCl ₃ , NH ₄ Cl, BF ₃ , ZnCl ₂ , PF ₅ , Al(OH) ₃ , disodium edetate (EDTA-2Na), triphenylphosphine, 2-methyl can be used. The group of imidazoles, etc., is not limited to these.

In the above description of the present invention, when referring to "(meth)acrylic acid", it is understood to include acrylic acid, methacrylic acid or both, and likewise, when referring to "(meth)acrylamide, it is understood to include Acrylamide, methacrylamide or both.

In the above, the C _1-4 alkoxy group means a linear or branched alkoxy group having 1 to 4 carbon atoms such as a methoxy group, an ethoxy group, a n-propoxy group or an isopropoxy group. , n-butoxy, second butoxy and tert-butoxy.

The present invention will be described in more detail by the following examples and examples, which are intended to illustrate the invention and not to limit the scope of the invention.

In the following synthesis examples and examples, the viscosity was measured by placing the solution at a constant temperature of 25 ° C and measuring it by a Brookfield viscometer.

The degree of saponification was measured according to the method of JIS-6726, and the degree of alkalization of the fully alkalized product PVA was measured by weighing about 3 g of the sample into a 300 ml Erlenmeyer flask, and 100 ml of distilled water was added. After heating in a water bath or a steam bath to completely dissolve it, it was cooled to room temperature. Accurately add 25ml of 0.1N NaOH solution and mix well. The mixture was allowed to stand at room temperature for two hours and then accurately added with 25 ml of 0.1 NH ₂ SO ₄ . The excess amount of H ₂ SO _{4 was} titrated with a 0.1 N NaOH solution. The indicator used is phenolphalein, and when the solution is pale pink, the titration end point is reached. At this time, the amount consumed by titrating the 0.1 N NaOH solution is recorded. And a separate blank test. The degree of alkalization can be determined from the weight of the remaining acetate group and the percentage of mole according to the following formula to the second decimal place.

A=0.6 ^* (ab) ^* F ^* 100/(S ^* P)

B=(44.05 ^* A)/(60.05-0.42A)

C=100-B

In the middle

A: weight percentage of residual acetic acid groups ((%)

B: percentage of moles of residual acetic acid groups (%)

C: alkalinity of the sample (in percent of mole) (%)

S: weight of sample (%)

P: purity of the sample (P = 100 - volatile - NaAc content) (%)

a: volume of 0.1 N NaOH solution (ml)

b: volume consumed by 0.1N NaOH solution in blank experiment (ml)

f: correction factor of 0.1N NaOH solution

Partial alkalization and ultra-low alkalinization PVA alkalinity determination method, the essence of about 0.5g (ultra-low alkalinized product scale about 0.4g) sample in a 300ml Erlenmeyer flask, and add 100ml of distilled water . After heating in a water bath or a steam bath to completely dissolve it, it was cooled to room temperature. Accurately add 25ml of 0.2N NaOH solution and mix well. The mixture was allowed to stand at room temperature for two hours and then accurately added with 25 ml of 0.2NH ₂ SO ₄ . The excess amount of H ₂ SO _{4 was} titrated with a 0.1 N NaOH solution. The indicator used is phenolphalein, and when the solution is pale pink, the titration end point is reached. At this time, the amount of 0.1 N NaOH solution titration is recorded. And a separate blank test. The degree of alkalization can be calculated according to the equation in the above section (1).

The degree of denaturation was measured by a Mitsubishi TN-05 total nitrogen analyzer. The following polyvinyl alcohol was placed in a 1% aqueous solution and analyzed by a total nitrogen analyzer. The total nitrogen amount measured was set to Appm, and the degree of denaturation was determined. It is calculated by the following formula.

Degree of denaturation (wt%)=A/1400 ^* 157

Synthesis Example - Synthesis of PVA (hereinafter abbreviated as M-PVA) modified with isobutoxy (meth) acrylamide [Synthesis Example 1]

Into a 5 liter reaction vessel equipped with a stirrer, 100 parts by weight of vinyl acetate, 12 parts by weight of methanol, 1.5 parts by weight of isobutoxymethyl acrylamide, and 0.0025 parts by weight of azobisisobutyronitrile were injected. Polymerization. The polymerization temperature was 68 ° C, the stirring rate was 90 rpm, the reaction time was 6 hours, and the solid content after the reaction was 47.9% by weight, and the conversion was 55%. The modified polyvinyl acetate into which isobutoxymethyl acrylamide was introduced was collected, and the methanol/vinyl acetate azeotropic monomer was removed. Adding to the obtained isobutoxymethyl propylene decylamine modified polyvinyl acetate, saponification is carried out on the modified polyvinyl acetate with a sodium hydroxide aqueous solution having a molar ratio of 0.01, the saponification temperature is 35 ° C, and the saponification time is 1.5 hours. PVA modified with isobutoxy (meth) acrylamide was obtained, which had a degree of saponification of 86.2 mol%, a viscosity of 48.5 cps, and a degree of denaturation of 4.6%. This modified PVA is referred to as M-PVA1.

[Synthesis Example 2]

Into a 5 liter reactor equipped with a stirrer, 100 parts by weight of vinyl acetate, 25 parts by weight of methanol, 3.0 parts by weight of isobutoxymethyl acrylamide, and 0.006 parts by weight of azobisisobutyronitrile were injected. Polymerization. The polymerization temperature was 68 ° C, the stirring rate was 90 rpm, the reaction time was 6 hours, the solid content after the reaction was 55% by weight, and the conversion was 68.5%. The modified polyvinyl acetate to which isobutoxymethyl acrylamide was introduced was collected, and a methanol/vinyl acetate azeotropic monomer was removed. Adding to the obtained isobutoxymethyl propylene decylamine modified polyvinyl acetate, adding saponification to the modified aqueous solution of polyvinyl acetate having a molar ratio of 0.014, the saponification temperature is 35 ° C, and the saponification time is 1.5 hours. PVA modified with isobutoxy (meth) acrylamide was obtained, which had a degree of saponification of 97.5 mol%, a viscosity of 26.1 cps, and a degree of denaturation of 7.56%. This modified PVA is referred to as M-PVA2.

[Synthesis Example 3]

Into a 5 liter reactor equipped with a stirrer, 100 parts by weight of vinyl acetate, 105 parts by weight of methanol, 5.0 parts by weight of isobutoxymethyl acrylamide, and 0.25 parts by weight of azobisisobutyronitrile were injected. Polymerization. The polymerization temperature was 68 ° C, the stirring rate was 90 rpm, the reaction time was 6 hours, and the solid content after the reaction was 44.1% by weight, and the conversion was 93.2%. The modified polyvinyl acetate to which isobutoxymethyl acrylamide was introduced was collected, and a methanol/vinyl acetate azeotropic monomer was removed. Adding to the obtained isobutoxymethyl propylene decylamine modified polyvinyl acetate, adding saponification to the modified polyvinyl acetate having a molar ratio of 0.01 to sodium hydroxide, the saponification temperature is 35 ° C, and the saponification time is 1.5. hour. PVA modified with isobutoxy (meth) acrylamide was obtained, which had a degree of saponification of 88.5 mol%, a viscosity of 5.8 cps, and a degree of denaturation of 8.8%. This modified PVA is referred to as M-PVA3.

[Examples 1 to 5 and Comparative Example 1]

M-PVA1~3 prepared in the above Examples 1 to 3 was used as an emulsifier for producing a polyvinyl acetate homopolymer. The emulsification method is an emulsification method in the general production of PVAc, but the emulsion polymerization reaction is carried out using the ratio shown in Table 1 below, and AlCl ₃ is optionally added as a crosslinking accelerator. The amounts of M-PVA and AlCl ₃ shown in Table 1 below are relative amounts when the vinyl acetate monomer is 100% by weight. The emulsion stability and the stability over time of the prepared PVAc emulsion were tested, and the results are also shown in Table 1. The emulsion stability was measured by placing the PVAc emulsion at 50 ° C for 7 days, "◎" when it was not layered, and "×" when layering. The stability over time was recorded as "pass" by placing the PVAc emulsion at 50 ° C for 7 days without gelation.

The prepared PVAc was then coated on a wood board and tested for wet peel strength and degumming time under heating at 100 ° C. The test results are shown in Table 1 below. The wet peel strength according to the EN204 D3 standard, after immersing in 23-27 ° C water for 4 days, and the peel strength ≧ 2 N / mm ² , indicates the specifications for use of the wood adhesive. And when the degumming time under heating at 100 ° C is more than 1 hour, it means that it meets the specifications for the use of wood adhesive.

In Table 1 below, Comparative Example 1 is the result of using unmodified PVA as an emulsifier.

[Examples 6 to 10 and Comparative Example 2]

Using the M-PVA prepared in the above Examples 1 to 3 as an emulsifier, a copolymer of polyvinyl acetate and decyl acrylate (manufactured by Momentive Performance Material Co., Ltd., trade name VeoVa ^TM 10, hereinafter referred to as "VV10") was produced. . The emulsification method is an emulsification method in the general production of PVAc, but the emulsion polymerization reaction is carried out using the ratio shown in Table 2 below, and AlCl ₃ is optionally added as a crosslinking accelerator. The amounts of M-PVA and AlCl ₃ shown in Table 2 below are relative amounts when the total amount of the vinyl acetate monomer and the VV10 monomer is 100% by weight. The emulsion stability and the stability over time of the prepared PVAc emulsion were tested, and the results are also shown in Table 1. The emulsion stability was measured by placing the PVAc emulsion at 50 ° C for 7 days, "◎" when it was not layered, and "×" when layering. The stability over time was recorded as "pass" by placing the PVAc emulsion at 50 ° C for 7 days without gelation.

The prepared PVAc was then coated on a wood board and tested for wet peel strength and degumming time under heating at 100 ° C. The test results are shown in Table 1 below. The wet peel strength is immersed in water of 23 to 27 ° C for 4 days according to the EN 204 D3 standard, and the peel strength ≧ 2 N/mm ² indicates the specification for use of the wood adhesive. When the degumming time under heating at 100 ° C is more than 1 hour, it means the specification for the use of the wood adhesive.

In Table 2 below, Comparative Example 2 is the result of using unmodified PVA as an emulsifier.

From the experimental data of the above Tables 1 and 2, it is shown that the emulsion stability using the M-PVA of the present invention is not caused by the addition of isobutoxy (meth) propylene oxime to the PVA as compared with Comparative Examples 1 and 2. The amine functional groups are different and the water resistance of EN204 D3 grade can be achieved without the addition of a crosslinking agent. And using the M-PVA of the present invention, the wet peel strength in the wood use and the degumming time in the heating are superior to the PVAc obtained by using the unmodified PVA as an emulsifier, and it is apparent that the present invention is C _{1- 4} alkoxy (meth) acrylamide modified polyvinyl alcohol can be used to manufacture emulsifiers in polyvinyl acetate homopolymers and copolymers, and can improve the obtained polyvinyl acetate. Water resistance.

Claims (6)

A C _1-4 alkoxy (meth) acrylamide modified polyvinyl alcohol (PVA) as an emulsifier in the manufacture of polyvinyl acetate and its copolymer resin, characterized by being made of vinyl acetate And C _1-4 alkoxy (meth) acrylamide is polymerized in the presence of a radical polymerization initiator, and then saponified by an alkali, and the degree of polymerization is 200 to 3000, and the degree of saponification is 80. Mole%~99.9% by mole. A polyvinyl alcohol (PVA) modified with C _1-4 alkoxy (meth) acrylamide as described in claim 1 in which the vinyl acetate monomer is used as 100 parts by weight, C _1-4 The amount of the alkoxy (meth) acrylamide is 0.5 to 15.0 parts by weight. Polyvinyl alcohol (PVA) modified with C _1-4 alkoxy (meth) acrylamide as described in claim 1 of the patent, which is modified with isobutoxymethyl acrylamide alcohol. A poly vinyl acetate emulsion of the manufacturing method, characterized by using as patent range 3 to 1 by any one of C _1-4 alkoxy (meth) acrylamide of modified polyvinyl alcohol ( PVA) as an emulsifier, the vinyl acetate is subjected to emulsion polymerization in the presence of a radical initiator, wherein the amount of PVA modified by C1-4 alkoxy (meth) acrylamide is relative to the vinyl acetate used The ester monomer is used in an amount of 0.5 to 30 parts by weight based on 100 parts by weight. A method for producing a polyvinyl acetate emulsion according to claim 4, wherein in addition to the vinyl acetate monomer, other monomers copolymerizable with vinyl acetate may be further included, in which case the weight ratio is other monomers: Vinyl acetate is in the range of (1~60): (99~40). A method for producing a polyvinyl acetate emulsion according to claim 5, wherein the other single system copolymerizable with vinyl acetate is selected from the group consisting of ethylene, propylene, butylene, vinyl chloride, (meth)acrylic acid, C _1-8 alkyl methacrylate, di C _1-4 alkyl maleate, acryl amine sulfonate and its salts, (meth) acrylamide and C _1-4 alkoxy One or more of the (meth)acrylamides.