JPH07268165A - Solvent-type vinyl acetate resin adhesive - Google Patents

Abstract

PURPOSE:To provide a solvent-type vinyl acetate resin adhesive usable for the bonding of general-purpose materials such as wood, ceramics or foamed polystyrene and the bonding of floorings such as vinyl chloride tile and board and having excellent storage stability, initial tackiness and adhesivity. CONSTITUTION:This vinyl chloride resin solution is produced by polymerizing (A) a main monomer component composed mainly of vinyl acetate and (B) a monomer component composed mainly of a (meth)acrylic acid ester in a solvent. The vinyl chloride resin contains 55-95wt.% of the main monomer component A and 5-45wt.% of the monomer component B and the light- transmittance of the vinyl acetate resin component is 5-85% at 660nm wavelength.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vinyl acetate-based resin solution, a method for producing the same, and a solvent-based vinyl acetate-based resin adhesive containing the vinyl acetate-based resin solution. The present invention relates to a solvent-type vinyl acetate-based resin adhesive having excellent storage stability, initial tackiness and adhesiveness, which is used for adhesion of general-purpose substrates such as expanded polystyrene, vinyl chloride tiles, and board flooring.

[0002]

2. Description of the Related Art It is well known that solvent-type vinyl acetate resins have been widely used as adhesives for bonding general-purpose substrates. However, it is a recent market requirement that the performance required of the adhesive also needs to be provided with the performance which is originally difficult for the resin. For example, a vinyl acetate resin adhesive is required to have initial adhesiveness and flexibility at low temperature in order to maintain high adhesive strength and workability for a long time. Therefore, when designing an adhesive, high adhesive strength, initial tackiness, and low temperature property must be taken into consideration. However, the adhesive strength, the adhesive strength, and the low temperature property are contradictory performances, and it is difficult to combine these performances.

In order to solve the above problems, a method of blending a vinyl acetate resin and a (meth) acrylic acid ester resin is known. However, a vinyl acetate resin and a (meth) acrylic acid ester resin dissolved in a solvent are used. It is very difficult to blend, and a gel state occurs during blending, or two phases are separated when left for a long time. This tendency is particularly remarkable in a methanol solvent that does not dissolve the (meth) acrylic acid ester resin.

Various studies have also been conducted on a method in which vinyl acetate and (meth) acrylic acid ester are added all at once to copolymerize vinyl acetate and (meth) acrylic acid ester. However, the copolymerization of vinyl acetate and (meth) acrylic ester is difficult because of the radical reactivity of each monomer, and the resin composition after the copolymerization reaction is vinyl acetate resin and (meth) acrylate. It becomes a mixture of acrylic ester resins, and the solution becomes a gel state, or demixing causes two-phase separation.

Further, there is known a method of continuously dropping a (meth) acrylic acid ester into vinyl acetate for a long time in order to facilitate a radical copolymerization reaction between vinyl acetate and a (meth) acrylic acid ester. In this case, the vinyl acetate- (meth) acrylic acid ester copolymer resin solution is transparent and does not separate into two phases even if left for a long time. However, under the present circumstances, the transparent vinyl acetate- (meth) acrylic acid ester copolymer resin solution cannot fully exhibit the performance of each resin, and can only exhibit the intermediate performance of both resins.

Under such circumstances, solvent-type vinyl acetate resin adhesives having the characteristics of both vinyl acetate resin and (meth) acrylic acid ester resin have been earnestly desired.
In particular, a solvent-type vinyl acetate-based resin adhesive that does not separate into two phases even in a polar solvent such as methanol that does not dissolve the (meth) acrylic acid ester resin is strongly desired.

[0007]

DISCLOSURE OF THE INVENTION The object of the present invention is to provide vinyl acetate- (meth), which is capable of exhibiting adhesiveness of vinyl acetate resin and physical properties of (meth) acrylic acid ester resin such as initial tackiness and low temperature. It is intended to provide an acrylic acid ester copolymer resin solution, a method for producing the same, and a solvent-based adhesive containing the resin solution.

[0008]

Means for Solving the Problems As a result of various investigations for solving the above problems, the present inventors have found that when copolymerizing vinyl acetate and (meth) acrylic acid ester, (meth) acrylic acid ester is used. The vinyl acetate resin and the (meth) acrylic acid ester resin have the respective characteristics of the vinyl acetate resin and the (meth) acrylic acid ester resin, and can be stored for a long period of time by intermittently adding each of them to the vinyl acetate in 3 to 15 times. Two
A cloudy vinyl acetate- (meth) acrylic acid ester copolymer resin solution that does not cause phase separation or gelation, has excellent storage stability, initial tackiness and adhesiveness, and has a light transmittance of 5 to 85% at a wavelength of 660 nm. It was found that the above was obtained, and the above object was achieved.

That is, the first aspect of the present invention is obtained by polymerizing a main monomer component (A) containing vinyl acetate as a main component and a monomer component (B) containing (meth) acrylic acid ester as a main component in a solvent. A vinyl acetate-based resin solution, wherein the resin composition has a main monomer component (A) unit content of 55 to 95% by weight, a monomer component (B) unit content of 5 to 45% by weight, and acetic acid The vinyl resin solution has a light transmittance of 5 to 85% at a wavelength of 660 nm.

In the second aspect of the present invention, a main monomer component (A) containing vinyl acetate as a main component and a monomer component (B) containing (meth) acrylic acid ester as a main component in a solvent are used as a polymerization catalyst. When producing a vinyl acetate resin solution by polymerizing in the presence of, the total amount of the monomer component (B) is divided into 3 to 15, and each divided monomer component (B) is intermittently added to the main monomer component (A). The method for producing a vinyl acetate-based resin solution according to the first aspect of the present invention is characterized in that the polymerization is carried out by adding each of them to the above at once.

Further, a third aspect of the present invention relates to a solvent-type vinyl acetate resin adhesive containing the vinyl acetate resin solution of the first aspect.

The present invention will be described in more detail below. The vinyl acetate resin solution of the present invention is obtained by polymerizing a main monomer component (A) containing vinyl acetate as a main component and a monomer component (B) containing a (meth) acrylic acid ester as a main component in a solvent. A vinyl acetate resin solution,
The resin composition has a main monomer component (A) unit content of 55 to
95% by weight, the content of the monomer component (B) unit is 5 to 4
It is 5% by weight and has a light transmittance of 5 to 85% at a wavelength of 660 nm.

When the content of the main monomer component (A) unit in the resin composition of the vinyl acetate resin solution is less than 55% by weight,
When used as an adhesive, it is difficult to maintain a permanent adhesive force, and when the content of the main monomer component (A) unit is more than 95% by weight, when used as an adhesive, the initial tackiness, It has the drawback of being less flexible.

The light transmittance of the vinyl acetate resin solution needs to be 5 to 85% as measured at a wavelength of 660 nm. It is preferable for the vinyl acetate resin solution to have a light transmittance of 5 to 85% at a wavelength of 660 nm in terms of long-term storage stability and manifestation of various physical properties as an adhesive when used as an adhesive. When the light transmittance exceeds 85%, the vinyl acetate resin solution is in a transparent state and has good long-term storage stability, but the performance of both the vinyl acetate resin and the (meth) acrylic acid ester resin is uniform. , Do not express their physical properties. Further, when the light transmittance is less than 5%, the vinyl acetate resin solution is in a cloudy state, and the performance of both the vinyl acetate resin and the (meth) acrylic acid ester resin can be exhibited, but the vinyl acetate resin solution is a gel. It is not suitable for use as an adhesive because it will be in a state or will be separated into two phases by long-term storage.

The vinyl acetate resin solution is produced by using the main monomer component (A) 55 to 95 containing vinyl acetate as a main component.
In producing a vinyl acetate-based resin solution by polymerizing 5% to 45% by weight of a monomer component (B) containing (meth) acrylic acid ester as a main component in a solvent in the presence of a polymerization catalyst, a monomer is used. The total amount of the component (B) is divided into 3 to 15 parts, and the divided monomer components (B) are intermittently added all at once to the main monomer component (A) to polymerize.

More specifically, the vinyl acetate-based resin solution is prepared by dissolving the main monomer component (A) containing vinyl acetate as a main component in a suitable solvent, generally methanol, ethanol, isopropyl alcohol, or methanol and ethyl acetate. Polymerization is started by dissolving in a mixed solvent to which acetone, acetone and the like have been added, and adding a polymerization catalyst thereto. Next, the total amount of the mixed liquid consisting of the monomer component (B) containing a (meth) acrylic acid ester as a main component, the solvent and the polymerization catalyst is divided into 3 to 15, and each divided monomer component (B) is the main monomer. It is manufactured by intermittently adding each of them to the component (A) and completing the polymerization.

When the total amount of the monomer component (B) containing a (meth) acrylic acid ester as a main component is divided into less than 3 parts and each of them is added together, the main monomer component (A) containing vinyl acetate as a main component is added. On the other hand, since a large amount of the monomer component (B) containing (meth) acrylic acid ester as a main component exists, the (meth) acrylic acid ester is preliminarily polymerized in the radical copolymerization reaction, and the resin composition is (meth) acrylic acid ester. It tends to be a blend of resin and vinyl acetate resin. Therefore, as described above, both are demixed to be in a gel state, or two phases are separated by long-term storage.
Moreover, when the total amount of the monomer component (B) containing (meth) acrylic acid ester as a main component is divided into more than 15 parts and each of them is added collectively, a monomer component (B) containing a (meth) acrylic acid ester as a main component is added. ) Is supplied little by little to the main monomer component (A) containing vinyl acetate as a main component, the copolymerization reaction is relatively easy to occur, and a transparent vinyl acetate resin solution is formed, and the vinyl acetate resin and (meth) acrylic resin A vinyl acetate-based resin solution that exhibits the average properties of acid ester resins, and is unlikely to be an adhesive that has both properties.

The total amount of the monomer component (B) containing the (meth) acrylic acid ester as a main component may be divided into 3 to 15 equal parts and the components may be added all at once. The total amount may be divided into 3 to 15 into arbitrary amounts and each may be added all at once, but it is preferable to divide the entire amount into 3 to 15 equal parts and add them all at once.

The time of the first batch addition of the monomer component (B) containing (meth) acrylic acid ester as the main component divided into 3 to 15 is not particularly limited, but generally, the main component containing vinyl acetate as the main component is used. It is preferable to add the monomer component (A) all at once within 3 hours after the initiation of polymerization. More preferably, the first batch addition time of the divided monomer component (B) is added all at once within 3 hours after the start of polymerization of the main monomer component (A).

The second batch addition time of the monomer component (B) containing (meth) acrylic acid ester as a main component divided into 3 to 15 is (meth) in the monomer component (B) added at the first batch. ) The polymerization rate of acrylic ester is 80
It is preferable to perform it when it reaches 100%. If the second divided monomer component (B) is added all together when the polymerization rate is less than 80%, gelation occurs and storage stability deteriorates. Separated monomer components after the third time
The batch addition timing of (B) is the same as above.

Monomer component (B) divided into 3 to 15
The polymerization rate of (meth) using gas chromatography
This can be known by measuring the residual rate of acrylic acid ester.

The reaction between the main monomer component (A) containing vinyl acetate as the main component and the monomer component (B) containing (meth) acrylic acid ester as the main component should be carried out at a temperature of 60 to 85 ° C. under a nitrogen stream. Is preferred.

The main monomer component (A) containing vinyl acetate as a main component used in the present invention may be vinyl acetate alone, or vinyl acetate and another unsaturated carboxylic acid copolymerizable with vinyl acetate. It may be a mixture with. Other copolymerizable unsaturated carboxylic acids include acrylic acid, methacrylic acid, maleic acid, fumaric acid, crotonic acid, itaconic acid and the like. The content of the other copolymerizable unsaturated carboxylic acid in the mixture of vinyl acetate and the other copolymerizable unsaturated carboxylic acid is at most 5% by weight, preferably 0.05 to 2% by weight. . When another copolymerizable unsaturated carboxylic acid is used in combination, the adhesion to the adherend is enhanced and the cohesive force of the adhesive is enhanced.

The monomer component (B) containing a (meth) acrylic acid ester as a main component used in the present invention may be a (meth) acrylic acid ester alone,
It may also be a mixture of a (meth) acrylic acid ester and another copolymerizable unsaturated carboxylic acid. As the (meth) acrylic acid ester, alkyl acrylate or alkyl methacrylate having an alkyl group having 2 to 8 carbon atoms is preferable, and the alkyl group may be linear or branched. Specific examples of such alkyl acrylate and alkyl methacrylate include ethyl acrylate, 2-ethylhexyl acrylate, n-butyl acrylate, n-butyl methacrylate and the like. Examples of other copolymerizable unsaturated carboxylic acids include the same unsaturated carboxylic acids used by mixing with the vinyl acetate. The content of the other copolymerizable unsaturated carboxylic acid in the mixture of the (meth) acrylic acid ester and the other copolymerizable unsaturated carboxylic acid is at most 4% by weight, preferably 0.2 to 2 % By weight. The other copolymerizable unsaturated carboxylic acid is used for the same purpose as in the case of blending with the main monomer component (A).

The polymerization catalyst used when polymerizing the main monomer component (A) containing vinyl acetate as a main component and the monomer component (B) containing (meth) acrylic acid as a main component is benzoyl peroxide. Aperoxides and azo compounds such as azobisisobutyronitrile are used. The amount of the polymerization catalyst used cannot be unconditionally determined because it depends on the type of the catalyst, reaction temperature, etc., but generally 0.01 to 5 parts by weight based on 100 parts by weight of the total amount of the monomer components,
It is preferably 0.1 to 2 parts by weight.

The vinyl acetate resin solution thus obtained is useful as an adhesive, and depending on the adhesive performance required for the adhesive, the type of (meth) acrylic acid ester,
The mixing ratio of the main monomer component (A) containing vinyl acetate as the main component and the monomer component (B) containing (meth) acrylic acid ester as the main component, the number of divided additions of the monomer component (B), the solvent, etc. are selected. It is preferable.

When the vinyl acetate resin solution of the present invention is used as an adhesive, additives generally used in the adhesive field, such as a thickener, a tackifier, and a plasticizer, are used as needed. Etc. may be blended. The vinyl acetate resin solution of the present invention can be used not only as an adhesive but also as a paint.

[0028]

The vinyl acetate resin solution of the present invention has good long-term storage stability despite the fact that it is cloudy, and shows the resin characteristics of both the vinyl acetate resin and the (meth) acrylic acid ester resin in the resin composition. It is presumed that the simultaneous withdrawal is due to the following reasons. The monomer component (B) containing (meth) acrylic acid ester as a main component, which is dividedly added to the main monomer component (A) containing vinyl acetate as a main component, is a copolymer with the main monomer component (A). And the (meth) acrylic acid ester resin mainly composed of the monomer component (B) is separated, and the (meth) acrylic acid ester resin is demixed with the vinyl acetate resin to make the appearance cloudy. However, vinyl acetate and (meth) acrylic acid ester copolymer act as a compatibilizing agent for compatibilizing vinyl acetate resin and (meth) acrylic acid ester resin, and good long-term storage stability of vinyl acetate resin solution. I think that This is because when a vinyl acetate resin solution is used as an adhesive, the dry form of the adhesive is a sea-island structure (sea is a vinyl acetate resin, and an island is a (meth) acrylic ester resin).
It seems that it brings out the performance of both resins.

[0029]

The present invention will be described in more detail with reference to Examples and Comparative Examples.

Example 1 A separable flask equipped with a condenser, a stirrer, and a thermometer was placed in a separable flask containing 100 parts by weight of vinyl acetate, 0.3 parts by weight of crotonic acid, 25 parts by weight of methanol, and 0.1 part of azobisisobutyronitrile. 3 parts by weight were charged, and polymerization was carried out under nitrogen reflux at 60 to 65 ° C. for 30 minutes with stirring. Thereafter, 3 parts by weight of mixed liquids (1) to (10) each consisting of 2 parts by weight of n-butyl acrylate, 0.1 parts by weight of methacrylic acid, 0.02 parts by weight of azobisisobutyronitrile, and 4 parts by weight of methanol were added.
The mixture was added 10 times at intervals of 0 minutes and polymerized for 15 hours.
After 15 hours, 57 parts by weight of methanol was added to give a solid content of 5
A vinyl acetate resin solution of 0.1% and a viscosity of 15,600 cps was obtained. The light transmittance of this product was 67%. Also,
The resin composition of the vinyl acetate-based resin solution has a content rate of the main monomer component (A) unit containing vinyl acetate as a main component of 83.
The content of the monomer component (B) containing 17% by weight and the monomer component (B) containing n-butyl acrylate as a main component was 17% by weight. In addition,
The polymerization rates of n-butyl acrylate after the mixed solutions (1) to (10) were added all at once and polymerized for 30 minutes were:
It was as follows. Mixed liquid (1) 94% Mixed liquid (2) 93% Mixed liquid (3) 94% Mixed liquid (4) 92% Mixed liquid (5) 95% Mixed liquid (6) 94% Mixed liquid (7) 94% Mixed Liquid (8) 96% Mixed liquid (9) 97% Mixed liquid (10) 96%

Comparative Example 1 Vinyl acetate (1) was placed in a separable flask similar to that used in Example 1.
00 parts by weight, crotonic acid 0.3 parts by weight, methanol 25
Parts by weight and 0.3 parts by weight of azobisisobutyronitrile were charged, and polymerization was performed under nitrogen reflux at 60 to 65 ° C. for 30 minutes while stirring. Then, mixed liquids (1) to (2) each consisting of 10 parts by weight of n-butyl acrylate, 0.5 parts by weight of methacrylic acid, 0.1 parts by weight of azobisisobutyronitrile, and 20 parts by weight of methanol are each added for 30 minutes. Polymerization was carried out for 15 hours by adding twice at intervals. After the polymerization, 57 parts by weight of methanol was added. This product was in a slightly gelled state, and two phases were separated one day after being taken out. The polymerization rates of n-butyl acrylate after the mixed solutions (1) and (2) were added all at once and polymerized for 30 minutes were as follows. Mixture (1) 67% Mixture (2) 71%

Example 2 A separable flask similar to that used in Example 1 was charged with 1 part of vinyl acetate.
00 parts by weight, crotonic acid 0.5 parts by weight, methanol 25
Parts by weight and 0.4 parts by weight of azobisisobutyronitrile were charged, and polymerization was carried out under nitrogen reflux at 60 to 65 ° C. for 40 minutes while stirring. Thereafter, a mixed liquid (1) containing 3 parts by weight of 2-ethylhexyl acrylate, 2 parts by weight of ethyl acrylate, 0.2 parts by weight of methacrylic acid, 0.07 parts by weight of azobisisobutyronitrile and 7 parts by weight of methanol.
(6) was added 6 times at intervals of 40 minutes each, and polymerization was carried out for 16 hours. After 16 hours, 87 parts by weight of methanol and 8 parts by weight of ethyl acetate were added to give a solid content of 45.3%,
A vinyl acetate resin solution having a viscosity of 6700 cps was obtained. The light transmittance of this product was 25%. In addition, the resin composition of the vinyl acetate-based resin solution is such that the content of the main monomer component (A) unit containing vinyl acetate as the main component is 76% by weight, and the monomer component containing 2-ethylhexyl acrylate and ethyl acrylate as the main components. The content of (B) was 24% by weight. The polymerization rates of 2-ethylhexyl acrylate and ethyl acrylate after the mixed solutions (1) to (6) were added all at once and polymerized for 40 minutes were as follows. Mixed liquid (1) 89% Mixed liquid (2) 86% Mixed liquid (3) 88% Mixed liquid (4) 87% Mixed liquid (5) 86% Mixed liquid (6) 86%

Comparative Example 2 Vinyl acetate (1) was placed in a separable flask similar to that used in Example 1.
00 parts by weight, crotonic acid 0.5 parts by weight, methanol 25
Parts by weight and 0.4 parts by weight of azobisisobutyronitrile were charged, and polymerization was carried out under nitrogen reflux at 60 to 65 ° C. for 40 minutes while stirring. Thereafter, 18 parts by weight of 2-ethylhexyl acrylate, 12 parts by weight of ethyl acrylate, 1.2 parts by weight of methacrylic acid, 0.42 of azobisisobutyronitrile.
A mixed liquid consisting of 1 part by weight and 42 parts by weight of methanol was continuously added dropwise over 5 hours, and the reaction was performed for 17 hours. After the reaction, 87 parts by weight of methanol and 7 parts by weight of ethyl acetate were added to obtain a vinyl acetate resin solution having a solid content of 45.0% and a viscosity of 4,500 cps. The light transmittance of this product was 101%. The resin composition of the vinyl acetate-based resin solution is such that the content of the main monomer component (A) unit containing vinyl acetate as the main component is 76% by weight, and the monomer component containing 2-ethylhexyl acrylate and ethyl acrylate as the main components (B ) Content was 24% by weight.

With respect to the vinyl acetate resin solutions obtained in Examples 1 and 2 and Comparative Examples 1 and 2, the long-term storage stability and the adhesion test between hard vinyl chloride and canvas were measured and evaluated. The results are shown in Table 1. The measurement of the polymerization rate, the light transmittance of the vinyl acetate resin solution, the storage stability, the adhesive strength and the initial adhesive strength were measured according to the following methods. Measurement of polymerization rate; Shimadzu Gas Chromatography (GC-1
4B) at an injection temperature of 220 ° C. and a column temperature of 110 ° C. (column: G100). Light transmittance: Using a Shimadzu UV-Visible spectrophotometer UV-160, the light transmittance at a wavelength of 660 nm of each vinyl acetate resin solution placed in a quartz cell was measured. Long-term storage stability: Each vinyl acetate resin solution is placed in a glass bottle, tightly stoppered, left in a dryer at 40 ° C., and the appearance state is visually evaluated. Adhesiveness: 1 for each vinyl acetate resin solution to hard vinyl chloride
Apply using a 0 mil applicator. Immediately, a canvas was attached with a 2 kg roller to prepare a test piece. After leaving this test piece under the conditions of 20 ° C. and 65% RH for 48 hours, the 180 ° peeling force was measured under the condition of a pulling speed of 200 mm / min. Initial adhesive strength: Each vinyl acetate resin solution is applied to a slate plate with a 20 mil applicator in an environment of 20 ° C. and 65% RH. After 5, 10 and 15 minutes from application, a metal column having a bottom area of 20 × 20 mm is attached. Two minutes after the test piece was attached to the metal piece, it was peeled in the vertical direction using a spring balance to measure the initial adhesive force.

[0035]

[Table 1]

[0036]

As is clear from Table 1, Examples 1 and 2
The vinyl acrylate-based resin solution obtained in Example 1 exhibits high adhesive strength and high initial adhesive strength, and the physical properties of vinyl acetate resin and acrylic resin are compatible with each other. On the other hand, in the vinyl acetate-based resin solution obtained in Comparative Example 1, the solution separated into two phases in a short time and did not become a product. Further, it can be seen that the vinyl acetate resin solution obtained in Comparative Example 2 becomes a transparent adhesive, and the initial tackiness is weaker than that in Example 2.

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Claims (3)

[Claims] 1. A vinyl acetate resin solution obtained by polymerizing a main monomer component (A) containing vinyl acetate as a main component and a monomer component (B) containing a (meth) acrylic acid ester as a main component in a solvent. In the resin composition, the content of the main monomer component (A) unit is 55 to 95% by weight, and the content of the monomer component (B) unit is 5 to 45% by weight,
A vinyl acetate resin solution, wherein the vinyl acetate resin solution has a light transmittance of 5 to 85% at a wavelength of 660 nm. 2. A main monomer component (A) containing vinyl acetate as a main component and a monomer component (B) containing a (meth) acrylic acid ester as a main component are polymerized in a solvent in the presence of a polymerization catalyst. When producing a vinyl acetate-based resin solution, the total amount of the monomer component (B) is divided into 3 to 15 parts, and each divided monomer component (B) is intermittently added to the main monomer component (A) at one time and polymerized. The method for producing a vinyl acetate-based resin solution according to claim 1, wherein 3. A solvent-type vinyl acetate-based resin adhesive containing the vinyl acetate resin solution according to claim 1.