JP3148659B2 - Method for producing and stabilizing polyvinyl acetate emulsion - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing a polyvinyl acetate emulsion by emulsion polymerization using acetoacetylated polyvinyl alcohol as a protective colloid, and a method for producing a polyvinyl acetate-based emulsion containing acetoacetylated polyvinyl alcohol by any method. The present invention relates to a method for stabilizing a vinyl acetate emulsion. More specifically, the present invention relates to a method for producing a polyvinyl acetate emulsion having improved viscosity during polymerization and improved viscosity stability during storage, and a method for stabilizing a polyvinyl acetate emulsion having improved viscosity stability during storage. .

[0002]

2. Description of the Related Art One or more selected from sulfites, bisulfites, metabisulfites, and thiosulfites (hereinafter referred to as "sulfites") are added to a polyvinyl acetate emulsion containing acetoacetylated polyvinyl alcohol. ) As a storage stabilizer is known to improve the viscosity stability during storage. For example,
No. 0-36218 discloses a method for stabilizing a polyvinyl acetate emulsion by adding sulfites to a polyvinyl acetate emulsion containing acetoacetylated polyvinyl alcohol. Also, Japanese Unexamined Patent Publication No.
JP-A-140405 discloses a method for stabilizing an aqueous emulsion by adding an oxycarboxylic acid and a sulfite to an emulsion containing acetoacetylated polyvinyl alcohol. Here, Tokiko 60
In the inventions described in JP-A-36218 and JP-A-5-140405, storage stabilizers such as sulfites are added later to a pre-polymerized emulsion.

[0003]

[Problems to be solved by the invention]
According to the stabilizing method described in JP-A-36218 or JP-A-5-140405, the viscosity stability of this emulsion may still be insufficient. In particular, when a polyvinyl acetate emulsion is produced by emulsion polymerization using acetoacetylated polyvinyl alcohol as a protective colloid, the viscosity of the emulsion may increase significantly during the polymerization. Polyvinyl acetate emulsions that have undergone a significant increase in viscosity during polymerization as described above not only cause inconvenience when used as a product, but also do not have sufficient storage stability even when sulfites are added after polymerization. there were.

[0004] It is an object of the present invention to provide a method for producing a polyvinyl acetate emulsion in which an increase in viscosity during polymerization is suppressed. Another object of the present invention is to provide a method for producing a polyvinyl acetate emulsion having a small increase in viscosity during polymerization and having good viscosity stability during storage. Still another object of the present invention is to provide a method for stabilizing a polyvinyl acetate emulsion having improved viscosity stability during storage.

[0005]

Means for Solving the Problems The present inventors have tried to make sulfites, which had been conventionally added as a storage stabilizer after polymerization, coexist at the time of emulsion polymerization, and this sulfite acts as a viscosity reducing agent. By doing so, the result was obtained that the rise in viscosity during polymerization was suppressed. Also,
By coexisting ethylenediaminetetraacetic acid or a salt thereof (hereinafter, referred to as "ethylenediaminetetraacetic acid (salt)") together with sulfites as the viscosity reducing agent at the time of polymerization, the effect of suppressing an increase in viscosity at the time of polymerization is further improved. Was found. Furthermore, it has been found that the viscosity stability of this ethylenediaminetetraacetic acid (salt) is increased when used in combination with sulfites as a storage stabilizer added to the emulsion after polymerization, compared to the case where sulfites are used alone. Thus, the present invention has been completed.

That is, a method for producing a polyvinyl acetate emulsion according to claim 1 is a method for producing a polyvinyl acetate emulsion by emulsion polymerization using acetoacetylated polyvinyl alcohol as a protective colloid. It is carried out in the presence of a viscosity reducing agent comprising sulfites.

The method for producing "acetoacetylated polyvinyl alcohol" as the protective colloid used in the present invention is not particularly limited, and it may be produced by any method, but is preferably obtained by reacting polyvinyl alcohol with diketene. Can be The polyvinyl alcohol used in obtaining the acetoacetylated polyvinyl alcohol is not particularly limited, but preferably has a residual acetate group of 0.1 to 15 mol%, an average degree of polymerization of 300 to 2600, and an average degree of saponification of 85 to 99 mol%. . The degree of acetoacetylation of acetoacetylated polyvinyl alcohol is 0.05 to 20 mol%,
More preferably, the range of 0.05 to 15 mol% is appropriate. An acetoacetylated polyvinyl alcohol having a degree of acetoacetylation of less than 0.05 mol% is not preferable because it does not contribute much to the water resistance of the emulsion. On the other hand, in the case of acetoacetylated polyvinyl alcohol having a degree of acetoacetylation of more than 20 mol%, the dispersion system is destroyed and a homogeneous emulsion cannot be obtained, or the obtained emulsion has poor stability. Is not preferred.

[0008] The "emulsion polymerization using acetoacetylated polyvinyl alcohol as a protective colloid" in the production method of the present invention is carried out before the start of emulsion polymerization, during the polymerization,
Except for adding acetoacetylated polyvinyl alcohol into the reactor at some point after the end of the polymerization,
It can be carried out by a general emulsion polymerization method. Addition of acetoacetylated polyvinyl alcohol
It is preferable to carry out before the start of emulsion polymerization or during the polymerization. The amount of acetoacetylated polyvinyl alcohol to be added is 0.1 to 30% by weight, preferably 0.2 to 20% by weight, based on the solid content of the emulsion obtained after the polymerization. If the amount is less than 0.1% by weight, the contribution to the improvement of the water resistance of the emulsion is small, and if it exceeds 30% by weight, the viscosity tends to increase significantly during the polymerization and the stability of the emulsion during storage decreases. That's why. Further, a surfactant used for ordinary emulsion polymerization may be used in combination with the acetoacetylated polyvinyl alcohol.

The "polyvinyl acetate emulsion" obtained by this emulsion polymerization includes vinyl acetate,
Examples include homopolymers or copolymers of vinyl acetate monomers such as vinyl propionate, and copolymers of vinyl acetate monomers with other vinyl monomers. Examples of the vinyl monomers include glycidyl groups such as acrylates, methacrylates, vinyl chloride, vinylidene chloride, acrylonitrile, methacrylonitrile, styrene, ethylene, propylene, glycidyl acrylate, glycidyl methacrylate, glycidyl divinyl ether, and glycidyl vinyl ether. Compound, N-
Methylol acrylamide, methylol group-containing compounds such as N-methylol methacrylamide and their alkoxy group-containing derivatives, carboxylic amides such as acrylamide and methacrylamide, carboxylic acids such as acrylic acid and methacrylic acid, divinyl adipate, divinyl succinate, Allyl cyanurate, diallyl fumarate, triallyl citrate, diallyl malate, vinyl versatate and the like can be mentioned.

[0010] The emulsion polymerization is carried out in the presence of "sulfites". By the action of the sulfites as a viscosity reducing agent, an increase in viscosity during polymerization can be suppressed to obtain a low-viscosity emulsion. "Sulfites" include sulfite, bisulfite, metabisulfite, sodium and potassium thiosulfite,
One or more selected from ammonium salts or amine salts. Of these, the use of bisulfite is particularly preferred. The sulfites may be added before the start of emulsion polymerization or during the polymerization. Further, the sulfites may be added at once or continuously, or may be added in plural times. Since the production operation is easy, it is preferable to start the polymerization immediately after the sulfites are charged into the reactor at once. The amount of the sulfite used is 0.0005 to 2.0 parts by weight based on 100 parts by weight of the solid content of the emulsion obtained after the polymerization.
More preferably, the amount is 0.001 to 1.0 part by weight, and even more preferably 0.003 to 0.8 part by weight. If the amount is less than 0.0005 parts by weight, the effect of the sulfites will be insufficient and the emulsion may be significantly thickened. On the other hand, the effect tends to be saturated when used in excess of 2.0 parts by weight, and when the obtained polyvinyl acetate emulsion is used as an adhesive, the adhesive strength and heat resistance may be adversely affected. It is not preferable because there is.

As the polymerization catalyst, a catalyst such as an azo-based initiator and a peroxide-based initiator that is used in ordinary emulsion polymerization may be used. Of these, when using a peroxide-based initiator, the decomposition of sulfites as a viscosity reducing agent is promoted, so the addition amount of the sulfites is large,
For example, it is preferably 0.01 to 2.0 parts by weight (more preferably 0.05 to 1.5 parts by weight) based on 100 parts by weight of the solid content of the emulsion obtained after the polymerization.

[0012] The method for producing a polyvinyl acetate emulsion according to claim 2 is characterized in that the method comprises the steps of:
Emulsion polymerization using alcohol as protective colloid
A method for producing a polyvinyl acetate emulsion.
And sulfites, bisulfites, metabisulfites as viscosity reducing agents
One or more selected from sulfates and thiosulfites
And ethylenediaminetetraacetic acid or ethylenediaminetetraacetic acid salt in the emulsion polymerization . The combined use of ethylenediaminetetraacetic acid (salt) and a sulfite as a viscosity reducing agent enhances the effect of suppressing the increase in viscosity during polymerization.

The "ethylenediaminetetraacetic acid (salt)" includes ethylenediaminetetraacetic acid or its sodium, potassium, and ammonium salts, and specific examples thereof include disodium ethylenediaminetetraacetate, trisodium ethylenediaminetetraacetate, and ethylenediaminetetraacetic acid. Examples thereof include tetrasodium acetate, dipotassium ethylenediaminetetraacetate, and diammonium ethylenediaminetetraacetate. One of these may be used alone, or two or more thereof may be used in combination. Of these, ethylenediaminetetraacetate is preferably used, and sodium salt is more preferably used. The preferred amount thereof is 0.001 to 1.0 part by weight, more preferably 0.003 to 0.5 part by weight, and further preferably 0.005 part by weight, per 100 parts by weight of the solid content of the emulsion obtained after the polymerization. ０．３0.3 parts by weight. Further, the weight ratio of ethylenediaminetetraacetic acid (salt) to sulfite 1 as a viscosity reducing agent is preferably 0.01 to 10.0, more preferably 0.05 to 5.0, and more preferably 0.1 to 5.0. More preferably, it is set to 1 to 2.0.

According to the production method of claim 1 or 2, the viscosity increase during polymerization is suppressed, and a low-viscosity polyvinyl acetate emulsion can be obtained. Such a low-viscosity polyvinyl acetate-based emulsion has good handleability during use, so that it can be suitably used for various applications, and has a lower viscosity during storage than an emulsion that has significantly increased viscosity during polymerization. Good viscosity stability. The mechanism by which the viscosity reduction during polymerization is suppressed by sulfites as a viscosity reducing agent is not always clear, but it is possible to prevent the reaction of acetoacetyl groups with aldehydes etc. contained in vinyl acetate monomers. Sex is considered. Also, the possibility of increasing the effect of suppressing thickening by using ethylenediaminetetraacetic acid (salt) in combination may be due to, for example, preventing the reaction of polyvalent metal ions and the like contained in water with acetoacetyl groups. . That is, since sulfites or ethylenediaminetetraacetic acid (salt) and sulfites prevent the acetoacetyl group from cross-linking during polymerization, it is supposed that the increase in viscosity is suppressed and a low-viscosity emulsion is obtained. .

[0015] As described above, the polyvinyl acetate emulsion obtained by the production method of claim 1 or 2 has better viscosity stability during storage than an emulsion that has undergone significant thickening during polymerization. Is, as described in claim 3,
By post-adding sulfites after polymerization of this emulsion, the viscosity stability during storage can be further improved. That is, the method for producing a polyvinyl acetate emulsion according to claim 3 is the method according to claim 1 or 2, wherein the polyvinyl acetate emulsion obtained by the emulsion polymerization is added with a storage stabilizer composed of sulfites. It is characterized by being added later.

The "sulfites" as storage stabilizers to be added later to the emulsion after polymerization include sulfites, bisulfites, metabisulfites, sodium thiosulfites, potassium sulfites as well as sulfites as viscosity reducing agents. One or two or more selected from salts, ammonium salts and amine salts can be used. Of these, the use of bisulfite is particularly preferred. The amount of the sulfite used is suitably 0.01 to 5.0 parts by weight, more preferably 0.02 to 2.0 parts by weight, based on 100 parts by weight of the solid content of the emulsion. If the amount is less than 0.01 part by weight, the effect of improving the viscosity stability by sulfites may be insufficient.
On the other hand, the effect tends to be saturated when used in an amount exceeding 5.0 parts by weight, and when the obtained polyvinyl acetate emulsion is used as an adhesive, the adhesive strength and heat resistance may be adversely affected. It is not preferable because there is.

Further, the present inventors have found that by using a sulfite and ethylenediaminetetraacetic acid (salt) in combination as a storage stabilizer to be added later to the emulsion after polymerization, the sulfite is added alone after the polymerization. It has been found that the viscosity stability of the emulsion is significantly improved. That is, the method for producing a polyvinyl acetate emulsion according to the fourth aspect is the production method according to the first or second aspect, wherein
Polyvinyl acetate emulsion obtained by John polymerization
Sulfites, bisulfites, metabisulfites, thiosulfites
A storage stabilizer comprising one or more selected from sulfates and ethylenediaminetetraacetic acid (salt) is added later .

As the "ethylenediaminetetraacetic acid (salt)" as a storage stabilizer, ethylenediaminetetraacetic acid or its sodium, potassium, or ammonium salt can be used in the same manner as ethylenediaminetetraacetic acid (salt) as a viscosity reducing agent. Can be. Of these, ethylenediaminetetraacetate is preferably used, and sodium salt is more preferably used. The preferred amount is 0.0005 to 0.5 part by weight, more preferably 0.001 to 0.2 part by weight, still more preferably 0.002 to 0.1 part by weight based on 100 parts by weight of the solid content of the emulsion. Parts by weight. Further, the weight ratio of ethylenediaminetetraacetic acid (salt) to sulfite 1 as a viscosity reducing agent is preferably 0.0005 to 1.0, and more preferably 0.001 to 0.5. Ethylenediaminetetraacetic acid (salt) as a storage stabilizer may be the same compound as or different from ethylenediaminetetraacetic acid (salt) used as a viscosity reducing agent, but it is preferable to use the same compound.

As described above, in the production method according to the fourth aspect, a storage stabilizer consisting of sulfites and ethylenediaminetetraacetic acid (salt) is added to the emulsion after polymerization. In the case of a polyvinyl acetate emulsion containing acetoacetylated polyvinyl alcohol, even when only sulfites are used as storage stabilizers for emulsions obtained by a method other than the production method according to claims 1 and 2. Has the effect of greatly improving the viscosity stability. That is, the method for stabilizing a polyvinyl acetate emulsion according to claim 5 comprises: (a) sulfites; (b) ethylenediaminetetraacetic acid (salt); A storage stabilizer consisting of:

Here, the “polyvinyl acetate emulsion containing acetoacetylated polyvinyl alcohol” is
After adding acetoacetylated polyvinyl alcohol and water to a polyvinyl acetate emulsion obtained by emulsion polymerization using acetoacetylated polyvinyl alcohol as a protective colloid, and a vinyl acetate polymer obtained by solution polymerization, the mixture is stirred and emulsified. This includes polyvinyl acetate emulsions obtained by adding acetoacetylated polyvinyl alcohol to a polyvinyl acetate emulsion obtained by an arbitrary method. As the “sulfites” and “ethylenediaminetetraacetic acid (salt)” in the stabilizing method according to the fifth aspect, the same compounds as the storage stabilizers according to the fourth aspect can be used. The amount of each component added to 100 parts by weight of the polyvinyl acetate emulsion and the weight ratio thereof are the same as in claim 4.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described specifically with reference to examples. (Examples 1 to 8) Acetoacetylated polyvinyl alcohol (manufactured by Nippon Synthetic Chemical Industry Co., Ltd., trade name “Gosefimer Z-200”) as a protective colloid, sodium bisulfite as a viscosity reducing agent or various ethylenediamines In the presence of tetraacetic acid (salt), vinyl acetate was emulsion-polymerized using an azo initiator. The solid content of each of the obtained emulsions was about 45%.
Met. Table 1 shows the quantitative ratio of each material and the type of the viscosity reducing agent used. The viscosity at 30 ° C. of the obtained emulsion is also shown in Table 1. In Table 1, "AA-PVA" means "acetoacetylated polyvinyl alcohol", and "EDTA (salt)" means "ethylenediaminetetraacetic acid (salt)". Sodium bisulfite as a storage stabilizer or various kinds of ethylenediaminetetraacetic acid (salt) were added later to these emulsions to prepare polyvinyl acetate emulsions of Examples 1 to 8. Table 1 shows the types of the storage stabilizers and the amounts of the storage stabilizers added to 100 parts by weight of the solid content.

(Embodiments 9 to 10)
Is a polyvinyl acetate-based emulsion obtained by adding sodium bisulfite and ethylenediaminetetraacetic acid (salt) as storage stabilizers to the emulsion obtained in (1). Example 10 is a polyvinyl acetate emulsion in which sodium bisulfite is added as a storage stabilizer to the emulsion obtained in Example 1, and ethylenediaminetetraacetic acid (salt) is not added later.

(Comparative Examples 1 and 2) Comparative Examples 1 and 2 were composed of sulfites and ethylenediaminetetraacetic acid (salt) as viscosity reducing agents.
Is a polyvinyl acetate emulsion in which emulsion polymerization is performed in the same manner as in Examples 1 to 8 except that no storage stabilizer is added. Table 1 shows the viscosity at 30 ° C. of the emulsion after polymerization. Comparative Example 2 is a polyvinyl acetate emulsion obtained by adding sodium bisulfite as a storage stabilizer to the emulsion obtained in Comparative Example 1 afterwards.

[0024]

[Table 1]

As shown in Table 1, Examples 1 to 3 in which a sulfite was used as a viscosity reducing agent during emulsion polymerization were used.
In No. 8, the increase in viscosity during polymerization was moderate, and a low-viscosity emulsion was obtained. Examples 1 to 7 in which a sulfite and ethylenediaminetetraacetic acid (salt) were used in combination as a viscosity reducing agent, and Example 8 in which only a sulfite was used.
From the comparison, it can be seen that the combined use of ethylenediaminetetraacetic acid (salt) further enhances the effect of preventing thickening.
In addition, it can be seen that the ethylenediaminetetraacetic acid salt has a higher effect of preventing thickening than the ethylenediaminetetraacetic acid, and that the sodium salt or potassium salt is particularly excellent in the effect of preventing thickening. On the other hand, in Comparative Example 1 in which no sulfites were used as a viscosity reducing agent, the viscosity of the emulsion increased significantly during polymerization.

Next, the prepared emulsion is allowed to stand in an environment of 40 ° C. and 70 ° C., and the viscosity (Pa ·
s) was measured and its viscosity stability was evaluated. The evaluation results are shown in Tables 2 and 3. The "relative viscosity" in Table 2 is 40 ° C.
X shows the viscosities of Examples 1 to 10 when the viscosity of Comparative Example 2 after 10 days is 100, and "increase rate%" is 40 ° C x 30 days after the viscosity immediately after the preparation of each emulsion is 100. Indicates viscosity. Further, “Relative viscosity” in Table 3 shows the viscosities of Examples 1 to 10 when the viscosity of Comparative Example 2 after 70 ° C. × 14 days was 100,
The “increase rate%” indicates the viscosity at 70 ° C. × 14 days when the viscosity immediately after preparation of each emulsion is 100. “Evaluation” in Tables 2 and 3 is a comprehensive evaluation of the relative viscosity and the rate of increase in viscosity, and indicates that the viscosity stability becomes better in the order of × <△ <○ ′ <○ <◎.

[0027]

[Table 2]

[0028]

[Table 3]

As shown in Tables 2 and 3, Comparative Example 1 in which no sulfite was added as a storage stabilizer was poor in viscosity stability and gelled within 24 hours. In Comparative Example 2 in which a sulfite as a storage stabilizer was added later, the viscosity stability was significantly improved as compared with Comparative Example 1. However, the viscosity is high immediately after preparation due to the remarkable increase in viscosity during polymerization, and the viscosity stability is not sufficient.

On the other hand, in Examples 1 to 10 in which emulsion polymerization was carried out in the presence of sulfites as a viscosity reducing agent and sulfites as a storage stabilizer were added later, all of the viscosity stability was good. . In Example 8 in which sulfite was used as a viscosity reducing agent, the relative viscosity was kept as low as about 49 to 53 at both 40 ° C. and 70 ° C. as compared with Comparative Example 2 in which the sulfite was not used. It is about 20% lower than Comparative Example 2. In Examples 1 to 7 in which ethylenediaminetetraacetic acid (salt) was used in combination as a viscosity reducing agent, the relative viscosity was kept lower at 48 to 29 or less, and the value of the viscosity increase rate was lower than that of Example 8. , Comparative Example 2
About 20 to 40% lower. Thus, it can be seen that the combined use of ethylenediaminetetraacetic acid (salt) further improves the viscosity stability as compared with the case where only the sulfite is used as the viscosity stabilizer. Examples 1, 2, 4, 5, and 7 in which the increase in viscosity during polymerization was small showed particularly excellent viscosity stability. Then, from the comparison of Examples 1 and 10 and Examples 8 and 9, by using sulfites and ethylenediaminetetraacetic acid (salt) in combination as storage stabilizers, compared with the case where only sulfites were used as storage stabilizers, It can be seen that the viscosity stability is further increased.

The present invention is not limited to the specific embodiments described above, but may be variously modified within the scope of the present invention in accordance with the purpose and application.

[0032]

According to the method for producing a polyvinyl acetate emulsion of the present invention, by conducting emulsion polymerization in the presence of a predetermined viscosity reducing agent, the viscosity increase during polymerization is suppressed and low viscosity polyvinyl acetate is obtained. A system emulsion is obtained. Such a low-viscosity polyvinyl acetate emulsion tends to have good viscosity stability during storage, and has good handleability when used as a product. If a predetermined storage stabilizer is added to the emulsion after polymerization, an emulsion having low viscosity and good viscosity stability can be obtained. Also,
According to the method for stabilizing a polyvinyl acetate emulsion of the present invention, a predetermined storage stabilizer is added to a polyvinyl acetate emulsion containing acetoacetylated polyvinyl alcohol obtained by an arbitrary method, whereby Viscosity stability can be improved.

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI // (C08K 13/02 3:30 5:17) (72) Inventor Koji Sato 1-3-18 Rokuno, Atsuta-ku, Nagoya-shi, Aichi Shoei Chemical Industry Co., Ltd. Nagoya Plant (72) Inventor Madoka Kono 1-3-18 Rokuno, Atsuta-ku, Nagoya City, Aichi Prefecture Shoei Chemical Industry Co., Ltd. Nagoya Plant (56) References JP-A-5-140405 (JP) JP-A-62-283186 (JP, A) JP-B-60-36218 (JP, B2) (58) Fields investigated (Int. Cl. ⁷ , DB name) C08F 118/08 C08F 2/22- 2/30 C08F 2/44 C08L 29 / 04,31 / 04 C08K 3/30 C08K 5/17-5/19 CA (STN)

Claims (5)

(57) [Claims] 1. A method for producing a polyvinyl acetate emulsion by emulsion polymerization using acetoacetylated polyvinyl alcohol as a protective colloid, the emulsion polymerization comprising sulfite, bisulfite, metabisulfite, thiosulfite. A process for producing a polyvinyl acetate emulsion, which is carried out in the presence of one or more viscosity reducing agents selected from salts. 2. An acetoacetylated polyvinyl alcohol.
Polyacetic acid by emulsion polymerization using as a protective colloid
A method for producing a vinyl emulsion, wherein a sulfite, a bisulfite, a metabisulfite is used as a viscosity reducing agent.
Salt, one or more selected from thiosulfites, and ethylenediaminetetraacetic acid or ethylenediaminetetraacetic acid salt
And coexist during the emulsion polymerization.
A method for producing a polyvinyl acetate emulsion. 3. A sulfite, a bisulfite, a sulfite, a bisulfite, and a polyvinyl acetate emulsion obtained by the emulsion polymerization.
3. A post-addition of one or more storage stabilizers selected from metabisulfites and thiosulfites.
A method for producing the polyvinyl acetate emulsion according to the above. 4. A polymer obtained by the emulsion polymerization.
In vinyl acetate emulsion, sulfite, bisulfite,
One or two selected from metabisulfite and thiosulfite
The method for producing a polyvinyl acetate-based emulsion according to claim 1 or 2, wherein a storage stabilizer comprising at least one or more species and ethylenediaminetetraacetic acid or ethylenediaminetetraacetic acid salt is added later . 5. A polyvinyl acetate emulsion containing acetoacetylated polyvinyl alcohol, comprising: (a) one or more selected from sulfites, bisulfites, metabisulfites, and thiosulfites; ) A method for stabilizing a polyvinyl acetate emulsion, comprising post-adding a storage stabilizer comprising ethylenediaminetetraacetic acid or ethylenediaminetetraacetic acid salt.