JPS6036163B2 - Method for producing synthetic resin emulsion - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a synthetic resin emulsion.

Conventionally, synthetic resin emulsions have been synthesized using low-molecular-weight emulsifiers such as alkyl sulfonates, alkyl sulfates, and alkyl carboxylates as emulsifiers, but a large amount of emulsifier is required to obtain a stable emulsion. The film produced from the emulsion thus obtained had the disadvantage of poor water resistance, heat resistance, film resistance, etc. In order to overcome the above-mentioned drawbacks, methods for producing emulsions using polymeric emulsifiers such as maleated polybutadiene and maleated polyisobrene have recently been proposed.

When such a polymer emulsifier is used, the polymer emulsifier used remains in the resulting emulsion, and when the emulsion is formed into a film, a silk-like structure is formed due to the reaction between the molecules of the polymer emulsifier. generates and forms a strong film,
The coating has the advantage of being excellent in water resistance and alkali resistance, but when it is formed into a coating when used as a paint, etc., the amount of coagulum produced increases during emulsion polymerization, and the diameter of the obtained emulsion particles becomes large. However, there are drawbacks such as reduced gloss and surface smoothness. The present invention is characterized in that when producing an emulsion, the emulsion is stably polymerized without the formation of coagulates, the resulting emulsion has a small particle size, has excellent stability, pigment miscibility, etc., and a film obtained from the emulsion. was developed for the purpose of producing a synthetic resin emulsion with excellent water resistance, heat resistance, weather resistance, etc. The gist of the method is to create a radical emulsion using maleated isoprene resin, which is made by adding a maleic compound to isoprene resin, as an emulsifier. When emulsion polymerizing a polymerizable monomer, an anionic surfactant represented by the general formula R-S03M or R-OS03M, and a general formula R-○ (CH2C ratio 0) are used together with the maleinized isoprene resin.
Nonionic surfactant represented by nH or general formula R-
An anionic nonionic surfactant represented by (CH2CH20)nS03M (in the above general formula, R means an organic group, M means an alkali metal or ammonium group, and n means a positive integer, respectively.

) is used in combination. Isof in the present invention.

The resin is a polymer mainly composed of isoprene, and may be an isoprene homopolymer or a copolymer of isopreso and a small amount of a copolymerizable monomer such as butadiene or 1,3-pentadiene. If the molecular weight of the isoprene resin is too small, it will not be effective as a polymer emulsifier, so it will not be effective in improving the water resistance etc. of the film formed by the emulsion produced using the maleinized isoprene resin. If the molecular weight is too large, the viscosity becomes too high, making it difficult to carry out the maleation reaction when maleinizing the isoprene resin. Therefore, the number average molecular weight of the isoprene resin is 500 to 150,000, especially 1.0
It is preferable that it is 00-100,000. Examples of the maleic compound used in the present invention include maleic acid, maleic anhydride, maleic anhydride derivatives such as maleic anhydride monomethyl ester, maleic anhydride diethyl ester, maleimide, and the like, with maleic anhydride being preferred. .

In the present invention, the above-mentioned ISOF.

The isoprene resin and the above-mentioned maleic compound undergo an addition reaction to form a maleinized isoprene resin, and any known method may be adopted for this synthesis method. For example, the isoprene resin and the maleic compound are combined at high temperature ( 20,000℃), or add isoprene resin and maleic compound to a solvent and heat it at a high temperature (about 200℃) while praying.
00) may be employed. Although the reaction can be carried out without a catalyst during this synthesis, it is preferable to add a peroxide catalyst such as benzoyl peroxide. In the present invention, when the acid value of the maleinated isoprene resin is less than 20, the emulsifying ability decreases and it becomes difficult to obtain a good emulsion, and when the acid value exceeds 350, the emulsifying ability decreases and it becomes difficult to obtain a good emulsion. Since the water resistance of films made from emulsions tends to decrease, maleated isoprene resins have an acid value of 20~20.
It is preferable to use one having an acid value of 350 and an acid value of 50 to 50.
200 is more preferable.

The amount of maleinized isoprene resin used is not limited in any way, but generally the amount of the radically polymerizable monomer 1
It is preferred to use 5 to 4 parts by weight to 0 parts by weight. In the present invention, the above-mentioned maleinized isoph. Emulsion polymerization is carried out using resin as an emulsifier, but when used as an emulsifier, it must be neutralized with a neutralizing agent such as methylamine, ethylamine, triethanolamine, ammonia, sodium hydroxide, or ammonium carbonate. It is preferable to use the Examples of the anionic surfactant represented by the above general formula used in the present invention include lauryl alcohol ester sodium sulfate, sodium dodecylbenzenesulfonate, sodium dodecylbenzenesulfonate dioctylsulfosuccinate, etc., and these are commercially available. Because it is easy to use.

Examples of nonionic surfactants represented by the above general formula include polyethylene glycol oleyl ether, polyethylene glycol lauryl ether, polyethylene glycol nonyl phenyl ether, polyethylene glycol octylphenyl ether, and polyethylene glycol decylphenyl ether. These are also commercially available and easy to obtain. Examples of the anionic-nonioso surfactant represented by the above general formula include polyoxyalkyl (or allyl) sulfate ammonium salt, polyoxyethylene nonylphenol sulfate sodium salt, etc., and these are also commercially available. There is.

In the present invention, one type of these surfactants may be used alone, or two or more types may be used simultaneously. The amount used is preferably 0.1 to 5% by weight of the radically polymerizable monomer to be subjected to emulsion polymerization. The radically polymerizable monomer used in the present invention is a monomer that is generally used in emulsion polymerization, such as methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, etc. acrylic acid alkyl esters, methacrylic acid alkyl esters such as methyl methacrylate, butyl methacrylate,
Glycidyl acrylate, glycidyl methacrylate, styrene, Q-methylstyrene, vinyl acetate, vinyltoluene, vinylpyridine, . Examples include butadiene, isoprene, chloroprene, acrylonitrile, methacrylonitrile, etc., and these monomers may be used alone or as a mixture of two or more. , acrylamide, methacrylamide, dimethylaminoethyl methacrylate, N-
Hydrophilic monomers such as methylol acrylamide, N-methylol methacrylamide, 2-hydroxyethyl methacrylate, and 2-hydroxypropyl acrylate may be used in combination.

In order to produce a synthetic resin emulsion by the method of the present invention, the above-mentioned maleinized isoprene resin and the above-mentioned surfactant are used together as emulsifiers to emulsion polymerize the radically polymerizable monomer. Any polymerization method may be employed.

For example, emulsion polymerization may be carried out by irradiation with radical-generating radiation such as gamma rays and electron beams, or by adding a radical polymerization initiator. Peroxides such as hydrogen oxide,
Azo compounds such as azobisisobutyronitrile, persulfate compounds such as ammonium persulfate and potassium persulfate, perchloric acid compounds, combinations of the above persulfuric compounds and reducing sulfoxy compounds, perchloric acid compounds and reducing sulfoxy compounds, etc. Examples include redox catalysts in combination with compounds.

The monomers, polymerization initiator, etc. may be added by any known method such as a batch addition method, a divided addition method, a continuous addition method, a monomer addition method, an emulsion addition method, etc. In addition, methods are used to make the reaction proceed smoothly, such as purging the reaction system with nitrogen, raising the temperature of the reaction system after the reaction is completed to remove residual monomers, and adding special catalysts. Good too.

The method for producing the synthetic resin emulsion of the present invention is as described above, in which a maleinized isoprene resin is used as an emulsifier, and the surfactant is preferably added in an amount of 0.1 to 5% by weight of the radically polymerizable monomer. Since they are used in the same amount, the polymerization is stable without the formation of coagulum during polymerization, and the resulting emulsion has good mechanical stability, storage stability, pigment miscibility, etc. Furthermore, the film made from the synthesized emulsion has excellent water resistance and alkali resistance compared to the film made from the emulsion synthesized using a low-molecular emulsifier alone. It has excellent heat resistance, film resistance, etc.

In addition, the emulsion produced by the method of the present invention has excellent miscibility with other water-soluble resins, etc., and can be modified by being combined with epoxy resin, phenol resin, urea resin, melamine resin, etc., depending on the purpose of use. can do. Furthermore, by adding a desiccant such as cobalt meftenoate or magnesium naphthenate, which are commonly used in paints, the water resistance and oil resistance of the film can be further improved. Therefore, according to the production method of the present invention, it is possible to produce an emulsion that can be used in paints, adhesives, resin processing, etc. and exhibits excellent performance.

The present invention will be explained below with reference to Examples.

The method for measuring acid value etc. is as follows. 1 acid value sample was dissolved in toluene/ethyl alcohol (7/3) and titrated with 0.1N potassium hydroxide solution using phenolphthalein as an indicator to determine the acid value.

2 Average particle size It was measured by turbidity method using Sakurada method.

3. Filter the emulsion that produces facial lumps with a 150-mesh stainless steel screen, thoroughly wash the residue with cold water, and then reduce the amount to 3 with 11 and 0.
The weight after drying by heating for a period of time was expressed as weight % based on the monomer charged.

4 Soak the water-resistant emulsion film in 20o○ ion-exchanged water,
Those with no decrease in transparency were considered to have good water resistance, and those with whitening were considered to have poor water resistance.

5 Alkali-resistant emulsion films were immersed in 1% by weight aqueous sodium hydroxide solution (20 circles), and the transmittance and water absorption were measured. Those with lower transmittance and higher water absorption were judged to have poor alkali resistance.

Reference Example 1 In a separate flask equipped with a dehydrator, a thermometer, a cooling tube, and a nitrogen inlet tube, isoprene resin with an average molecular weight of 29,000 (manufactured by Kuraray Co., Ltd., trade name LIR-30) 20
After 0 pm, 40 pm of maleic anhydride was supplied to replace the inside of the system with nitrogen.

Next, the temperature was raised to 180 to 185 oo while stirring, and the mixture was reacted for 5 hours to obtain a pale yellow solid maleinized isoprene resin.

The acid value of the obtained resin was 95. Reference Example 2 A maleinized isoprene resin was obtained in the same manner as in Reference Example 1 using 200 g of the isoprene resin used in Reference Example 1 and 50 g of maleic anhydride.

The oxidation value of the obtained resin was 117. Example 1 Into a separate flask equipped with a rope punch, a thermometer, a cooling pipe, a nitrogen introduction pipe, and a dropping funnel, 20% of the resin obtained in Reference Example 1, 140% of ion-exchanged water, and 28%
Aqueous ammonia was supplied for 5 days to replace the inside of the system with nitrogen.

Next, the temperature was raised to 70 qo while holding a light, and the polymer emulsifier was completely dissolved in 1 hour.

When the solution was cooled to room temperature and the pH was measured, the pH was 9.3.

Next, 4 hours of 10% polyoxyalkyl samphite ammonium salt solution and 80 hours of 2-ethylhexyl acrylate were added, and after purging with nitrogen for 3 seconds while offering candlelight, 0.1 hour of potassium persulfate was dissolved. 10 hours of ion-exchanged water was added, the temperature was raised to 70°C, and the mixture was reacted for 6 hours.

The reaction proceeded uniformly, and no coagulum was observed.
The pH of the obtained emulsion was 8.7, and the mold content was 39.
0%, and the particle size of the emulsion was 152 mm, which was good. Next, the obtained emulsion was applied onto a glass slope and left at room temperature for 3 days to obtain a sheet having a film thickness of about 200 mm. The obtained sheet was hard and transparent, and its water resistance was good with no change at all after 7 hours. Also, the alkali resistance is 92% in transmittance and 10% in water absorption after 7 hours.
It was good. Comparative Example 1 Emulsion polymerization was carried out in the same manner as in Example 1, except that the resin 20 obtained in Reference Example 1 was used as an emulsifier and the polyoxyalkyl sulfate ammonium salt was not added.

Although the polymerization proceeded uniformly, the amount of coagulum produced was 1.5%. The pH of the obtained emulsion was 8.8, the solid content was 39.4%, and the particle size was as large as 310. Next, a sheet having a film thickness of about 200 mm was produced from the obtained emulsion in the same manner as in Example 1. The obtained sheet was hard and transparent, and its water resistance was good with no change at all after 7 hours. Also, the alkali resistance is 7
After the incubation period, the transmittance was 94% and the water absorption rate was 9%. Comparative Example 2 Emulsion polymerization was carried out in the same manner as in Example 1, except that a 10% polyoxyalkyl sulfate ammonium salt solution was used as the emulsifier and no polymer emulsifier was used.

Polymerization proceeded uniformly, and no coagulum formation was observed.
The pH of the obtained emulsion was 3.7, and the solid content was 39.
4%, and the particle size was 140 mm. Next, a sheet having a film thickness of about 200 mm was produced from the obtained emulsion in the same manner as in Example 1. The resulting sheet was hard and transparent. Next, water resistance and alkali resistance were measured. Water resistance was very poor and whitening was observed after 1 hour.
In addition, in the alkali resistance test, the transmittance after 7 feeding hours was 20%,
The water absorption rate was poor at 50% after 24 hours and 65% after 7 hours. Example 2 A 10% solution of polyethylene glycol lauryl ether was used instead of polyoxyalkyl sulfate ammonium salt as a combined low-molecular emulsifier, and butyl methacrylate was used instead of 2-ethylhexyl acrylate as a radically polymerizable monomer. An emulsion was obtained in the same manner as in Example 1 except that 30 days of emulsion was used.

Amount of coagulum produced, pH, solid content of the obtained emulsion,
and particle diameters are shown in Table 1. Next, a sheet was prepared from the obtained emulsion in the same manner as in Example 1, and its water resistance and alkali IJ resistance were evaluated. The evaluation results are shown in Table 1. Comparative Example 3 An emulsion was obtained under the same conditions as in Example 2, except that no polyethylene glycol lauryl ether was used as a combined emulsifier.

Amount of coagulum produced, pH, solid content of the obtained emulsion,
and particle diameters are shown in Table 1. Next, a sheet was prepared from the obtained emulsion in the same manner as in the examples, and its water resistance and alkali resistance were evaluated. The evaluation results are shown in the same table. Comparative Example 4 An emulsion was obtained under the same conditions as in Example 2, except that a 10% solution of polyethylene glycol lauryl ether was used as an emulsifier and no polymer emulsifier was used.

Amount of coagulum produced, pH, solid content of the obtained emulsion,
and particle diameters are shown in Table 1. Next, a sheet was prepared from the obtained emulsion using the same machine as in the example, and its water resistance and alkali resistance were evaluated. The evaluation results are shown in the same table. Example 3 Example except that 20% of the resin obtained in Reference Example 2 was used as the polymer emulsifier, 10% sodium n-dodecylbenzenesulfonate solution was used as the low-molecular emulsifier, and styrene 809 was used as the radically polymerizable monomer. I got emulsion on the same plane as I did on 1.

Amount of coagulum produced, pH, solid content of the obtained emulsion,
and particle diameters are shown in Table 1. Next, a sheet was prepared from the obtained emulsion in the same manner as in Example 1, and its water resistance and alkali resistance were evaluated. The evaluation results are shown in the same table. Comparative Example 5 An emulsion was obtained under the same conditions as in Example 3, except that sodium n-dodecylbenzenesulfonate was not used at all as a combined emulsifier.

Amount of coagulum produced, pH, solid content of the obtained emulsion,
and particle diameters are shown in Table 1. Next, a sheet was prepared from the obtained emulsion in the same manner as in the examples, and its water resistance and alkali resistance were evaluated. The evaluation results are shown in the same table. Comparative Example 6 An emulsion was obtained under the same conditions as in Example 3, except that an emulsifier and a 10% solution of sodium n-dodecylbenzenesulfonate were used and no polymeric emulsifier was used.

Amount of condensate produced, pH, solid content of the obtained emulsion,
and particle diameters are shown in Table 1. Next, a sheet was prepared from the obtained emulsion in the same manner as in the examples, and its water resistance and alkali resistance were evaluated. The evaluation results are shown in the same table. Table 1

Claims (1)

[Scope of Claims] 1. When emulsion polymerizing a radically polymerizable monomer using a maleated isoprene resin obtained by adding a maleic compound to an isoprene resin as an emulsifier, a compound of the general formula R-SO_3M or Anionic surfactant represented by R-OSO_3M, nonionic surfactant represented by general formula R-O(CH_2CH_2O)nH or general formula R-O(CH_2
Anionic-nonionic surfactant represented by CH_2O)nSO_3M (in the above general formula, R is an organic group, M
represents an alkali metal or ammonium group, and n represents a positive integer. ) A method for producing a synthetic resin emulsion, characterized by using in combination. 2. The manufacturing method according to item 1, wherein the maleated isoprene resin has an acid value of 20 to 350. 3. The manufacturing method according to item 1, wherein the maleated isoprene resin has an acid value of 0 to 200. 4 The amount of surfactant added is 0.0% of the radically polymerizable monomer.
The manufacturing method according to item 1, wherein the content is 1 to 5% by weight. 5 The number average molecular weight of the isoprene resin is 500 to 1500
00. The manufacturing method according to item 1. 6. The manufacturing method according to item 1, wherein the maleate is maleic anhydride.