JPH0153285B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a polymer of 1-acetoxy-1,3-butadiene.

Conventionally, 1-acetoxy-1,3-butadiene polymers were produced by using azobisisobutyronitrile or benzoyl peroxide as a radical polymerization initiator.
It was obtained by bulk polymerization, solution polymerization, or emulsion polymerization using persulfate as a radical polymerization initiator at a high temperature of 60 to 90°C. (For example, Macrornol. Chem176(2), 341, 1975) However, it has been reported that polymers obtained by conventional methods can only have a number average molecular weight of 2000 to 5000 at most due to the chain transfer reaction of monomers. has been done.

Furthermore, if emulsion polymerization is carried out at high temperatures as in the cited literature, not only will the polymer be colored yellow to red, which is a practical problem, but depending on the polymerization conditions, the ester groups may undergo hydrolysis and undergo significant deterioration. It has the disadvantage of being stored away.

The polymer of 1-acetoxy-1,3-butadiene is a polymer of conjugated diene with a polar group, and various developments can be considered as a new polymer material. Some polymers have limited uses and are of poor practical use.

As a result of intensive research into the polymerization method of 1-acetoxy-1,3-butadiene, the present inventors found that the low-temperature emulsion or suspension polymerization method is
The present invention was achieved by discovering that the method is suitable for the polymerization of 1,3-butadiene and that a highly useful polymer can be obtained.

That is, the present invention is a method for producing a 1-acetoxy-1,3-butadiene polymer, which is characterized by carrying out emulsion or suspension polymerization at -15 to 50°C in the presence of a radical polymerization initiator.

According to the present invention, conventional 1-acetoxy-1,
Compared to the production method of 3-butadiene polymer, 1- is not colored and is hardly hydrolyzed.
A polymer of acetoxy-1,3-butadiene can be obtained.

Furthermore, according to the present invention, it is possible to obtain polymers of 1-acetoxy-1,3-butadiene with various molecular weights ranging from low molecular weight to high molecular weight.
This is a production method suitable for obtaining a polymer of 1,000,000 1-acetoxy-1,3-butadiene.

Next, the present invention will be explained in detail.

1-acetoxy-1,3-butadiene, the monomer used in the present invention, can be obtained by acetoxylating butadiene in the presence of a noble metal catalyst such as palladium, or by converting crotonaldehyde into acetoxylate in the presence of acetic anhydride and an acetate of an alkali metal. It can be obtained by heating at 1-acetoxy-1,3-butadiene obtained by these reactions is a mixture of cis and trans forms, but the monomers used in the present invention can contain either the cis form or the trans form alone. The mixture may be arbitrarily mixed. Further, it may contain impurities to the extent that it does not cause any inconvenience.

Polymerization is carried out at -15 to 50°C, which is lower than the conventional temperature of 60 to 90°C. In order to carry out polymerization smoothly, it is necessary to select an initiation system. As the radical polymerization initiator, persulfates such as ammonium persulfate and potassium persulfate, so-called redox-based radical polymerization initiators, peroxides, azo-based radical polymerization initiators, etc. can be used, but in terms of polymerization rate, polymerization In order to perform this process smoothly, redox-based radical polymerization initiators or azo-based radical polymerization initiators with good low-temperature decomposition properties,
For example, 2,2'-azobis(4-methoxy-2,
Preferred are 4-dimethylvaleronitrile), 2,2'-azobis-(2,4-dimethylvaleronitrile), and among these, redox-based radical polymerization initiators are particularly preferred.

As conventionally known redox-based radical polymerization initiators, peroxides such as hydrogen peroxide, cumene hydroperoxide, diisopropylbenzene hydroperoxide, para-menthane hydroperoxide, etc., and reducing agents as activators such as sulfuric acid It is used in combination with ferrous salts such as ferrous iron, and if necessary, aliphatic polyamines, sulfites, etc. as oxygen scavengers, and the peroxide is usually 0.001 to 10 parts by weight per 100 parts by weight of monomer. , reducing agent: 0.001 to 1.0 parts by weight, oxygen scavenger: 0
~1.0 part by weight is used, but it can be appropriately selected depending on the polymerization conditions.

In emulsion polymerization using a redox-based radical polymerization initiator, for example, monomers are emulsified in an aqueous system in the presence of an appropriately selected surfactant, and in the presence of the redox-based radical polymerization initiator, electrolytes and pH Adding regulators, polymerization degree regulators, etc., -
Polymerization is carried out at 15-50°C, preferably -5-20°C.

In addition, as a radical polymerization initiator, persulfate, peroxide, or an azo compound is used in the same way as when a redox radical polymerization initiator is used.
It is also possible to carry out emulsion or suspension polymerization at 15-50°C. In this case, too, at a high polymerization temperature of 60 to 90°C, not only is the polymerization stability poor and it is difficult to obtain a product with a high molecular weight, but the polymer may become colored, the monomer undergoes hydrolysis, and changes to crotonaldehyde. Because the polymer is hydrolyzed, industrially useful polymers of constant quality cannot be obtained. Further, at a polymerization temperature lower than -15°C, a sufficient polymerization reaction rate cannot be obtained. However, the polymerization temperature is −15
By adjusting the temperature to ~50°C, preferably from 20 to 45°C, these drawbacks can be greatly improved. Especially when using an azo radical polymerization initiator, 20
Suspension polymerization at ~45°C is preferred.

Examples of surfactants include so-called anionic surfactants such as _C12 to _C18 fatty acid soaps, disproportionated rosin acid soaps, sodium alkylarylsulfonates, and sodium alkylnaphthalenesulfonates;
Either a nonionic surfactant or an anionic/nonionic surfactant may be used, and of course a mixture of these may be used.

The surfactant is usually used in an amount of 0.1 to 10 parts by weight per 100 parts by weight of the monomer. Redox radical polymerization initiators such as persulfates, peroxides, and azo compounds other than redox radical polymerization initiators are
It is usually used in an amount of 0.01 to 10 parts by weight per 100 parts by weight of monomer.

Potassium chloride, sodium phosphate, sodium sulfate, and the like are used as electrolytes as necessary for smooth polymerization, and are usually added in an amount of 0.001 to 1 part by weight per 100 parts by weight of monomer. In order to adjust the degree of polymerization, long-chain alkyl mercaptan, diisopropylsantogen disulfide, carbon tetrachloride, etc. can be used, and are usually used in an amount of 0.01 to 10 parts by weight per 100 parts by weight of monomer. Water may contain impurities to the extent that they do not interfere, and may contain organic solvents such as methanol and acetone to the extent that they do not inhibit emulsification or suspension. Usually 50 to 1000 parts of water to 100 parts by weight of monomer
Polymerization is carried out by adding parts by weight, but this is not particularly limited.

In such polymerization, monomers, polymerization aids, etc. may be added all at once, and it is of course possible to use an inkjet method if necessary. Also, polymerization is
The polymerization may be carried out up to a polymerization rate of 100%, but depending on the purpose, such as to prevent gelation of the polymer, a polymerization terminator or the like may be added midway to terminate the polymerization.

The polymer can be recovered from the reaction system after the completion of the polymerization reaction by various means. For example, the polymer can be recovered by precipitating the polymer by adding the above reaction system to a large amount of methanol, and the purified polymer can be recovered by washing thoroughly with methanol and drying. Obtainable.

According to the present invention, 1-acetoxy-
A polymer of 1,3-butadiene can be obtained.

The present invention will be specifically described below with reference to Examples.

The molecular weight of the polymer in the examples was calculated using GPC (gel permeation chromatography) in terms of polystyrene.
The mixture was stirred for hours and filtered through a 200 mesh wire mesh, and the residue on the wire mesh was used as a gel fraction.

[Example 1] In a separable glass flask with a capacity of 1,
5g of sodium lauryl sulfonate in 400g of _N2 sewage
and 7 g of sodium dodecylbenzenesulfonate, and while stirring, 1-acetoxy- in which 0.7 g of tertiary dodecyl mercaptan was dissolved.
200 g of 1,3-butadiene was added and emulsified at 8°C. 0.04 g of sodium hydrogen sulfite was charged into this. Also sodium ethylenediaminetetraacetate
0.1 g of ferrous sulfate, 0.2 g of sodium formaldehyde sulfoxylate were charged. While stirring thoroughly at 8°C, 4 g of paramenthane hydroperoxide was charged and polymerized for 10 hours. Then N,N-diethylhydroxylamine
2.0g was added to stop the reaction.

An emulsion free of coagulum was obtained, and the polymerization rate was 91%. When this emulsion was added dropwise to the methanol in Step 3 while stirring, a white polymer was precipitated. This polymer was thoroughly washed with methanol and dried. This polymer was dissolved in tetrahydrofuran and GPC
When the molecular weight was measured using a method, the number average molecular weight was 160,000.

Also, put 1 g of this polymer in 100 g of acetone,
When the mixture was stirred at 30°C for 24 hours and filtered through a 200-mesh wire mesh, no gel content was observed. The spectrum of this polymer measured using an infrared spectrophotometer includes:
No absorption of hydroxyl groups due to hydrolysis was observed.

[Example 2] In a 600 ml glass pressure bottle, under _N2 , 100 g of 1-acetoxy-1,3-butadiene, 200 g of water, 5.0 g of sodium dodecylbenzenesulfonate, 0.02 g of ferrous sulfate, and alkylnaphthalene sulfate. Sodium fluorinate 0.15g, ethylenediaminetetraacetate 0.1g, sodium dimethyl sulfoxylate
0.1g, cumene hydroperoxide 0.1g, tertiary dodecyl mercaptan 0.2g,
As a result of polymerization at ℃ for 24 hours, an emulsion with a polymerization rate of 67% and no coagulum was obtained. When this product was purified in the same manner as in Example 1, a colorless polymer was obtained. The number average molecular weight was 280,000, no gel content was observed, and no hydrolysis occurred.

[Example 3] In a 600 ml glass pressure-resistant bottle, under _N2 , add 100 g of 1-acetoxy-1,3-butadiene, 200 g of water, 5 g of sodium dodecylbenzenesulfonate, 0.1 g of ammonium persulfate, and 0.5 g of tertiary dodecyl mercaptan. The mixture was prepared and reacted at 42°C for 20 hours.

An emulsion with almost no coagulum is obtained,
The polymerization rate was 89%. When the polymer was purified in the same manner as in Example 1, it was a white polymer with a number average molecular weight of 160,000 and no gel content was observed.
No hydrolysis occurred either.

[Example 4] Example 3 except that 1.0 g of 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile) was used instead of ammonium persulfate.
Polymerization was carried out in the same manner as in Example 3.

An emulsion free of coagulum was obtained with a polymerization rate of 85%, and the purified polymer was free from coloration and no gel content was observed. This product had a number average molecular weight of 140,000 and was not hydrolyzed.

[Comparative Example 1] Polymerization was carried out in the same manner as in Example 3 except that the reaction temperature was changed to 60°C. The entire polymerization system was a coagulated product, and the polymer was brown in color.

Claims (1)

[Claims] 1. In the presence of a radical polymerization initiator at -15 to 50°C,
1- characterized by emulsification or suspension polymerization
A method for producing an acetoxy-1,3-butadiene polymer. 2. The method according to claim 1, which uses a redox radical polymerization initiator.