JPS6059242B2 - Method for producing one-component curing emulsion polymer - Google Patents

Description

Detailed Description of the Invention The present invention provides a one-component curing emulsion that has room temperature curing performance and has excellent emulsion dispersion stability and application workability in various industrial fields without using an emulsifier. This article relates to methods for producing polymers.

Conventionally, emulsion polymerization has been commonly used in the production of high polymerization degree polymers, and although the produced polymers are water-insoluble, they remain dispersed in water and have a relatively low viscosity, making them useful for use. It has excellent workability and is used in a wide range of industrial fields, including paint vehicles, adhesives, fiber processing agents, cement admixtures, and paper processing agents.

However, this emulsion polymer is not necessarily perfect in terms of applied performance, and there are many cases where it cannot be used.

In other words, since the emulsifier used in the emulsion polymerization process is adsorbed to the polymer micelles, if this is applied directly as a film former, the water resistance, alkali resistance, acid resistance, gloss, and transparency of the film will be reduced. , insufficient tensile strength, insufficient adhesion when used as an adhesive, and toxicity when used as food packaging materials. The method of removing this emulsifier is to make it into a lacquer through processes such as salting out, washing with water, dissolving in organic solvents, etc. However, this method requires complicated work and high expense in processes such as salting out and washing with water. Not only is this necessary, but wastewater treatment is also not easy.

Furthermore, the use of lacquer causes air pollution due to organic solvents, and many problems still remain in these respects.

Against this background, much research has been conducted in recent years on techniques for producing emulsion polymers that do not use emulsifiers, and the fields of application of emulsion polymers have expanded.

A typical example is JP-A-53-039387.
The following inventions can be mentioned.

The invention described above involves polymerizing a hydrophobic vinyl monomer mixture containing 3 to (up to) weight percent α,β ethylenically unsaturated carboxylic acid in an organic solvent, and then polymerizing the resulting polymer-containing liquid therein. An aqueous emulsion polymer is obtained by removing the organic solvent and adding water and a basic substance, and the aqueous emulsion polymer thus obtained is used to polymerize a radically polymerizable vinyl monomer. This is a method for producing an aqueous emulsion polymer.

The aqueous emulsion polymer obtained by this production method showed remarkable improvements in water resistance, weather resistance, transparency, etc. compared to conventional emulsions, and expanded the performance limits of emulsion polymers.

However, even with this technology, water resistance, chemical resistance, etc. are still not fully satisfactory.

This invention eliminates these drawbacks, has performance comparable to that of a flat polymer, and has superior effects in terms of emulsion dispersion stability and application workability in various industrial fields, compared to emulsion polymers using emulsifiers. ．． There is a novel method for producing a room temperature curable emulsion polymer having the following properties.

The gist of this invention is 3 to 60% (weight%;
A hydrophobic vinyl monomer mixture containing α,β ethylenically unsaturated carboxylic acid (the same applies hereinafter) is polymerized in an organic solvent in the presence of a polymerization catalyst, and from the resulting polymer-containing liquid, removing said organic solvent and adding water and a basic substance for neutralizing said carbonic acid to produce a precursor consisting of an aqueous emulsion polymer, and using the precursor thus obtained, One or more monomers or mixed monomers selected from vinyl monomers and/or polyunsaturated monomers are polymerized in the presence of a polymerization catalyst, and before this polymerization reaction, or during or after polymerization, 0.5 to 20% of a polyvalent epoxy compound based on the total amount of the solid content of the precursor and the monomer or mixed monomer to be polymerized using this precursor. The first invention is a method for producing a one-component curing emulsion polymer, which is characterized by adding a volatile basic epoxy compound. The second invention is a method for producing a one-component curable emulsion polymer by adding a substance.

The polymerization method of this invention can be specifically achieved as follows.

First, in the first step, a mixture of 3 to 60% α,β ethylenically unsaturated carboxylic acid and 97 to 40% of another hydrophobic vinyl monomer copolymerizable with this is added in the presence of a polymerization catalyst. While stirring in an organic solvent, preferably 50 to 120
Polymerization is carried out while controlling the temperature range of °C, and the organic solvent is evaporated by heating under normal pressure or reduced pressure, and then removed from the system, while a basic substance is used to neutralize water and the carboxylic acid. The material is added to form an aqueous emulsion polymer, which serves as a precursor.

The second step is a step of carrying out emulsion polymerization using the above precursor as an emulsifying medium and further mixing a crosslinking agent. One or more mixed monomers selected from saturated monomers are added sequentially or all at once in the presence of a polymerization catalyst, or a precursor and the mixed monomers are added to a polymerization catalyst. while maintaining the reaction temperature at 40 to 90°C and polymerizing according to a conventional method,
Before and after this polymerization reaction, 0.5 to 20% of a polyvalent epoxy compound is added to the total amount of the solid content of the precursor and the monomer or mixed monomer to be polymerized using this precursor. There is a method for producing a one-component curing emulsion polymer by adding

Furthermore, in the second invention, in order to impart chemical stability over time to this one-component curing emulsion polymer, a solid content of a precursor and the monomer polymerized using this precursor are added. Or 0.5 to 20 based on the total amount of mixed monomers
% of a polyvalent epoxy compound and a volatile basic substance in an amount equal to or more than the same mole relative to the epoxy group before and after the polymerization reaction.

To explain the first step in more detail, α,
The amount of β-ethylenically unsaturated carboxylic acid is limited to the range 3-60% as mentioned above, and less than 3% is used in the second step emulsion polymerization step following precursor preparation and thereby. This impairs the dispersion stability of the finished emulsion polymer.

Moreover, if the amount used exceeds 60%, emulsification will not occur and the polymerization in the second step following the first step cannot be carried out smoothly.

It is desirable to control the polymerization temperature within the range of 50 to 120°C; if the polymerization temperature is less than 50°C, there is a risk that the polymerization reaction will stop or a sudden runaway reaction will occur.

In addition, if the polymerization temperature exceeds 120°C, it is difficult to obtain a highly polymerized product, and it is necessary to remove the organic solvent and add water and a basic substance for neutralization after the polymerization.
This may impair the emulsion stability of the precursor obtained by the aqueous emulsion displacement operation. Here, examples of the α,β ethylenically unsaturated carboxylic acid include itaconic acid, methacrylic acid, acrylic acid, crotonic acid, maleic acid, cinnamic acid, fumaric acid, glutaconic acid, and sorpic acid.

Further, as other hydrophobic vinyl monomers that can be copolymerized with these, any hydrophobic monomer that can undergo a normal radical polymerization reaction may be used, such as methyl acrylic acid or methacrylic acid, Esters such as ethyl, propyl, butyl, isobutyl, 2-ethylhexyl, lauryl, cyclohexyl, hydroalkyl, acrylonitrile, methacrylonitrile, styrene, diethylaminoethyl methacrylate, diethylaminoethyl acrylate, dimethylaminoethyl methacrylate, dimethylaminoethyl acrylate, N -Methylolacrylamide is one example.

The organic solvent used in the polymerization reaction is selected depending on the type of monomer to be subjected to the polymerization. Solvents that have the lowest azeotropy with water or with water are convenient, to name a few: methyl alcohol, ethyl alcohol, propyl alcohol, isopropyl alcohol, ethyl acetate, methyl acetate, cyclohexane, n-
Examples include hexane, n-heptane, acetone, methyl ethyl ketone, triol, penzole, and xylol.

In addition, among the organic solvents, water-soluble organic solvents in particular can be used by mixing with water, and the mixing ratio of water is preferably 30% or less, and if it exceeds 30%, polymerization may occur. During the reaction, the polymer precipitates or gels, making it difficult to maintain good dispersibility. The polymerization catalyst is appropriately selected from ordinary radical polymerization catalysts depending on the type of monomer and solvent. Examples include 2,2''-azohisisobutyronitrile, benzoyl peroxide, and ammonium persulfate. The amount of the catalyst added is usually arbitrarily used within the range of 0.1 to 5% based on the total amount of the mixed monomers.

Aqueous emulsification substitution is performed by adding water and a basic substance while evaporating the organic solvent by heating and removing it from the system.
This can be achieved by neutralizing the carboxylic acid in the produced polymer, but water and a basic substance can be added simultaneously or separately before and after the removal of the organic solvent. It may also be added all at once or sequentially during the aqueous emulsification replacement operation. The above-mentioned basic substance has excellent emulsion dispersion stability within the addition range required to neutralize 20 to 90n101% of carboxylic acid.

There are many types of basic substances that can be used, but if you want something with excellent physical properties such as water resistance and chemical resistance as described above in the field of application, ammonia or a relatively low boiling point organic substance is preferable. Amine salts are preferred, typical examples of which include triethylamine and trimethylamine.

Further, the evaporative removal of the organic solvent can be adjusted as appropriate depending on the purpose, but for the purpose of avoiding flammability, the organic solvent should account for 55% or less of the total amount of solvent.

Furthermore, if a large amount of the organic solvent remains in the system, the emulsification and dispersibility during the polymerization reaction in the second step may be reduced, which is not preferable.

Note that the organic solvent to be removed by evaporation can be recovered by a condenser and reused if necessary.

Next, to explain the second step, one or more monomers or a mixture of monomers selected from vinyl monomers and/or polyunsaturated monomers used in the second step. The weight ratio of solid content (hereinafter referred to as RM.J) and solid content of the precursor in the first step (hereinafter referred to as RpJ) is approximately M/P = 95/5 to 20/80 = 19 to 0.25. When M/P exceeds 19, it is difficult to maintain emulsion stability.

In addition, if the weight ratio is less than 0.25, the emulsion stability is sufficient), but since the precursor increases relatively compared to the above weight ratio range, the precursor has a relatively low degree of polymerization, and the carboxylic acid Since the emulsion polymer contains a large number of groups, the application performance of the produced emulsion polymer deteriorates, and in particular, only those with significantly impaired water resistance and chemical resistance can be obtained.

As for the type of vinyl monomer used in the polymerization, most monomers that are used in normal radical emulsion polymerization can be used.One example is acrylic acid alkyl esters (e.g. , methyl acrylate, ethyl, propyl, butyl, isobutyl, tertiarybutyl, 2-ethylhexyl, lauryl, tridecyl, cyclohexyl, stearyl, etc.), methacrylic acid alkyl esters (e.g. methyl, ethyl, propyl, butyl, isobutyl methacrylate) , Tersiabutyl, 2-
Ethylhexyl, lauryl, tridecyl, stearyl,
cyclohexyl, etc.), hydroxyalkyl acrylate, or hydroxyalkyl methacrylate (specifically, 2-hydroxyethyl, 2-hydroxypropyl, 3
- Acrylate or methacrylate having a hydroxyalkyl group such as hydroxypropyl, 4-hydroxybutyl, 5-hydroxyamyl, 6-hydroxyhexyl, 7-hydroxyheptyl, 8-hydroxyoctyl, 9-hydroxynonyl, 10-hydroxydecyl, etc. )
, acrylonitrile, methacrylonitrile, styrene,
Maleic acid mono- or dialkyl ester, fumaric acid mono- or dialkyl ester, bromostyrene,
Chlorostyrene, butyl vinyl ether, itaconic acid mono- or dialkyl ester, methacryl chloride, α-methylstyrene, methyl vinyl ketone, vinyl chloride, vinyl acetate, vinyl bromide, vinylidene chloride, vinylpyridine, vinylpyrrolidone, vinyltrimethoxysilane, Glycidyl acrylate, glycidyl methacrylate, N-methylol acrylamide, dimethylaminoethyl methacrylate, dimethylaminomethyl acrylate, diethylaminoethyl methacrylate, diethylaminoethyl acrylate, etc. are important.

Types of polyunsaturated monomers include ethylene glycol dimethacrylate, 1,3-butylene glycol diacrylate, neopentyl glycol dimethacrylate, polyethylene glycol diacrylate, trimethylolpropane trimethacrylate, trimethylol, ethane triacrylate, etc. esters of polyvalent acrylic or polyvalent methacrylic, halogenated polyacrylic such as dipromneopentyl glycol dimethacrylate, or halogenated polyvalent methacrylate, butadienes such as 1,4-butadiene and isoprene, N, Examples include polyvalent allyl compounds such as N-methylenebisacrylamide, glyogyzal tetraallyl ether, and allyl shuggar.

Further, examples of polyvalent epoxy compounds include compounds containing two or more epoxy groups in one molecule,
For example, bisphenol A diglycidyl ether, bisphenol A diβ-methylglycidyl ether, bisphenol F diglycidyl ether, tetrahydroxylphenylmethane tetraglycidyl ether, resorcinol diglycidyl ether, brominated bisphenol A diglycidyl ether, novolak diglycidyl ether, polyalkylene Glycidyl ethers such as glycol diglycidyl ether, glycerin triglycidyl ether, pentaerythritol glycidyl ether, diglycidyl esters such as phthalic acid diglycidyl ester, tetrahydrophthalic acid diglycidyl ester, dimer acid diglycidyl ester, tetraglycidyl diaminodiphenylmethane , polyvalent glycidylamines such as triglycidyl isocyanurate, linear aliphatic epoxy resins such as epoxidized polybutadiene, and epoxidized soybean oil.

The amount of these polyvalent epoxy compounds added is adjusted depending on the purpose, and the solid content P of the precursor produced in the first step is
It is usually carried out at approximately 0.5 to 20% with respect to the total of the monomer or mixed monomer M in the second step, and 0.5%
Otherwise, one-component curing performance cannot be expected, and no improvement in the physical properties of the film, such as water resistance and chemical resistance, as described above, is observed.

Moreover, if it exceeds 20%, the crosslinking reactivity is too strong and may result in gelation, resulting in a lack of chemical stability over time.

In addition, volatile basic substances are used to suppress the crosslinking reaction caused by polyvalent epoxy compounds as mentioned above and to stabilize the emulsion polymerization solution over time. When using emulsion polymers with one-component curing performance, the cross-linking reaction is promoted because volatile basic substances also evaporate along with water evaporation from the coating film, and as a result, the one-component curing performance is improved. There are things that manifest themselves.

The addition ratio of the volatile basic substance is effective when it is equal to or more than the equivalent molar amount to the epoxy group, and is preferably carried out in a range of 1.2 to 5 moles. If the amount is less than the equivalent molar amount, no effect can be expected, and if it is added in excess, the concentration of the polymer will relatively decrease, which is not practical. These volatile basic substances include ammonia, hydrazine,
Examples include monoethanolamine, triethanolamine, pyridine, and morpholine.

In addition, the polymerization catalyst in the second step is selected from water-soluble ones as described above, such as ammonium persulfate, potassium persulfate, hydrogen peroxide, percarbonate, peracetic acid, perphthalic acid, t-butyl Examples include peroxymaleic acid, azobiscyanovalerate, 2,2-azobis[2-(amidinopropane)hydrochloride], and the like.

Moreover, it can also be used as a redox polymerization catalyst by using it in combination with an organic or inorganic reducing agent such as sodium sulfite or sodium L-sorbate, if necessary. The amount of these polymerization catalysts used is approximately 0 relative to the monomer.
．． If the amount used is less than 0.01%, the start of the polymerization reaction will be extremely slow, and if the amount used is more than 5%, the polymerization reaction will be rapid, and the molecular weight of the resulting polymer will be too low for practical use. Not on point.

Although the polymerization reaction can be carried out in the air, it is preferable to carry out the reaction in an inert gas such as nitrogen gas in order to improve the polymerization yield.

Further, the reaction temperature is usually preferably controlled within the range of 40 to 90°C.

If the reaction temperature is below 40°C, the start of the polymerization reaction will be extremely slow, and even if the polymerization reaction starts, it may stop midway.If the reaction temperature is above 90°C, the emulsified particles will tend to lack mechanical stability. .

The one-component curable emulsion polymer obtained by the method of the present invention can be made into a one-component type that is stable even during long-term storage despite (1) containing a cross-linking agent; This eliminates the need for complicated operations such as mixing and dissolving, which are required for two-component emulsion polymers.

(2) Since it does not contain an emulsifier, the water resistance of the obtained one-component curable emulsion polymer is significantly improved, and there is no need to remove the emulsifier in the manufacturing process.
It is possible to simplify and speed up the steps required for manufacturing.

(3) In terms of use, the film has extremely excellent water resistance, alkali resistance, acid resistance, solvent resistance, transparency, gloss, tensile strength, and adhesive strength, and can have performance comparable to that of Lutzker. can.

There are some that have the following effects. Next, the manufacturing method of the present invention will be explained in more detail with reference to Examples and Comparative Examples.

Examples 1 and 2, Comparative Examples 1 and 2 "<First step> A separable flask was equipped with a stirrer reflux condenser, 3k9 of propyl alcohol (PA) was added, and the mixture was heated to a temperature of 80°C while stirring. Later, acrylic acid butyl ester (BA), methacrylic acid methyl ester (BA), methacrylic acid methyl ester (
Il! 4MA), mixed monomer 2k9 consisting of acrylic acid (AA), and azobisisobutyronitrile (ABN)
10y were added continuously over a period of 7 hours each, and the polymerization reaction was carried out while maintaining the internal temperature at 80°C.

After that, the internal temperature was maintained at 80° C. for 3 hours, and the reaction was continued until the polymerization yield reached % of bean paste.

Next, the PA during polymerization was evaporated by heating the jacket, and 1.5k9 was recovered using a condenser, and the polymerization liquid was concentrated.

Next, add 1k9 of water and toluethylamine (TE
An arbitrary amount of A) was added, and the remaining PA was azeotropically evaporated with water while stirring, and 2 kg of water was further added to produce a precursor.

In this case, the results shown in Table 1 were obtained by varying the blending amounts of the monomer and 'IEA.

Second step> In a 3e separable flask equipped with a stirrer and a reflux condenser,
Each precursor produced in the first step was mixed with 562.5y1 of water, 1162.5y of water, . BA637.5y. ．． MMA382
．． 5y1 Acrylic acid ethyl ester (EA) 153y1
Trimethylolethane triacrylate (TMETA)
38.25y1 diglycidyl orthophthalate (GF)
63.75f was added, and 2-cyano-2-propylformamide 30y was used as a polymerization catalyst at a temperature of 70
The polymerization was carried out at 0.degree. C., and the results shown in Table 2 were obtained.

As a result, the concentration of AA in the resin content of the precursor was 3.
If it is less than 6%, dispersibility is poor and precipitation tends to occur;
It has been found that when the content exceeds 0%, the emulsion polymerization in the second step cannot be carried out smoothly because the precursor does not emulsify. Example 3
, Comparative Example 3 First Step> In a 300e capacity autoclave (equipped with a hanging stirrer, heating and cooling jacket, condenser, and distillate receiving tank),
Add 150k9 of isopropyl alcohol (IPA) and heat while stirring until the temperature reaches 75℃,
8k9, EA32k9, methacrylic acid (IVAA) 20
k9, ABNO. 5k9 was added continuously over a period of 10 hours each time, and polymerization was carried out while maintaining the reaction temperature at 75°C.

Thereafter, the polymerization reaction was continued for about 5 hours to obtain a polymerization yield of %.

Next, the IPA in this polymerization solution was evaporated by heating the jacket, passed through a condenser, and collected in a distillate receiving tank to about 75k9, and added 200k9 of water to this concentrated polymerization solution,
10.5k9 of 8% ammonia water was added, and while stirring, the remaining 1PA and water were azeotropically evaporated to completely remove IPA.

The polymerization liquid had a resin content of 4% by weight and had a fluorescent milky white color with excellent dispersibility, and was used as a precursor material for the second step.

<Second step> 4.5 kg of precursor and 33 k9 of water were added to a 150 e capacity autoclave (equipped with a hanging stirrer, heating/cooling jacket, condenser, and distillate receiving tank), and the temperature was 70°C.
After raising the temperature to , 2-ethylhexyl acrylate (
2 upper HA) 8.4k9, EAl6.4k9, MMA9.
2k9, triethylene glycol dimetal rylate 7.
6k9 and ammonium persulfate (APS) 0.42k9 were added, and polymerization was carried out at a temperature of 70° C. in a conventional manner to obtain an emulsion polymer having a fluorescent milky white color (Comparative Example 3).

To this emulsion polymer, 0.42 k9 of polyethylene glycol diglycidyl ether (PEGDGE) was added and mixed well (Example 3). As a result, as shown in Table 3, the polymerization solutions obtained in Example 3 and Comparative Example 3 were both fluorescent milky white emulsion polymers with excellent dispersibility. It was found that the polymer of Example 3 was significantly superior to the polymer of Comparative Example 3 in each physical property value of the film.

In addition, in Table 3, ◎ mark is the best, 〇゛ mark is
"Slightly superior,""Δ" means "slightly inferior," and "X" mean inferior.

Examples 4, 5, and 6 A volatile basic substance was added to each of the emulsion polymers obtained in Examples 1, 2, and 3, and the pot life was investigated.

Comparing this with Examples 1, 2, and 3 without additives, the fourth
Shown in the table.

In addition, Example 4 is the same as Example 1, Example 5 is the same as Example 2,
Further, in Example 6, a volatile basic substance was added to the polymer of Example 3.

As seen in the results in Table 4, it was found that the pot life was greatly improved.

Claims (1)

[Scope of Claims] 1 A hydrophobic vinyl monomer mixture containing 3 to 60% by weight of α,β ethylenically unsaturated carboxylic acid is polymerized in an organic solvent in the presence of a polymerization catalyst to obtain a polymer. Obtain a polymer-containing liquid, remove the organic solvent contained in the polymer-containing liquid, and add a basic substance for neutralizing water and the carboxylic acid to produce a precursor consisting of an aqueous emulsion polymer. death,
Using this precursor, in the presence of a polymerization catalyst, one or more monomers selected from vinyl monomers and/or polyunsaturated monomers, or a mixture of monomers before, during, or after the polymerization reaction, 0 to the total amount of the solid content of the precursor and the monomer or mixed monomer polymerized using this precursor. ．．
A method for producing a one-component curable emulsion polymer, which comprises adding 5 to 20% by weight of a polyvalent epoxy compound. 2 A hydrophobic vinyl monomer mixture containing 3 to 60% by weight of α, β ethylenically unsaturated carboxylic acid is polymerized in an organic solvent in the presence of a polymerization catalyst to obtain a polymer-containing liquid. removing the organic solvent contained in the polymer-containing liquid and adding a basic substance for neutralizing water and the carboxylic acid to produce a precursor consisting of an aqueous emulsion polymer;
Using this precursor, one or more monomers or a mixture of monomers selected from vinyl monomers and/or polyunsaturated monomers are produced in the presence of a polymerization catalyst. polymerization, before, during, or after the polymerization reaction,
0.5 based on the total amount of the solid content of the precursor and the monomer or mixed monomer to be polymerized using this precursor.
A method for producing a one-component curable emulsion polymer, which comprises adding ~20% by weight of a polyvalent epoxy compound and a volatile basic substance in an amount equal to or more than the same mole as the epoxy group.