JPS6221003B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention uses a monoolefin having 2 to 10 carbon atoms and α.
Regarding the method for producing a copolymer with β-unsaturated dicarboxylic acid anhydride, more specifically, it suppresses the formation of deposits on the walls of the polymerization tank and efficiently produces a monoolefin copolymer.
The present invention relates to a method for producing an α/β-unsaturated dicarboxylic acid anhydride copolymer. Copolymers obtained by radical copolymerization of monoolefins such as ethylene, propylene, isobutylene, and styrene with α/β-unsaturated dicarboxylic acid anhydrides such as maleic anhydride and itaconic anhydride can be obtained by the radical copolymerization of monoolefins such as ethylene, propylene, isobutylene, and styrene. Dispersants for dyes and pigments in the form of metal salts, ammonium salts, esters, etc., cement admixtures, gypsum dispersants, mud admixtures, floor polishing agents, adhesives, paints, viscosity index improvers, pour point depressants, etc. It is known that it can be used in the fields of These copolymers are generally obtained by carrying out polymerization in a solution or suspension state in a reaction-inert solvent such as ketones, aromatic hydrocarbons, aliphatic hydrocarbons, etc. When polymerization is carried out in a suspended state, deposits tend to form on the inner wall of the polymerization vessel and the stirring blade during polymerization, which not only reduces the yield of the copolymer but also reduces the thermal efficiency of the reaction system. It is also a cause of deterioration in quality. This tendency is particularly noticeable when aliphatic hydrocarbons such as pentane, hexane, heptane, cyclohexane, etc. are used, and is a major obstacle to improving productivity. Therefore, attempts have been made to adjust the particle size of the produced polymer by using dispersants and to suppress the formation of deposits on the walls of the polymerization tank. A method using an equimolar copolymer of 14 to 18 α-olefins and maleic anhydride (US Pat. No. 3,729,451),
- A method using a half-ester or half-amide of a copolymer of olefin and maleic anhydride (JP-A-Sho
51-95489), but it was hoped that many more dispersants would be developed. An object of the present invention is to provide a method for efficiently producing a monoolefin-α/β-unsaturated dicarboxylic acid anhydride copolymer by suppressing the formation of deposits on the inner wall of a polymerization vessel, a stirrer, etc. The object of the present invention is to use a monoolefin having 2 to 10 carbon atoms and an α/β-unsaturated dicarboxylic acid anhydride as a dispersant when radically copolymerizing them in a solvent that does not dissolve the resulting polymer. This is achieved by having alkenylsuccinic anhydride present in the polymerization system. The monomer used in the present invention has 2 carbon atoms.
~10 monoolefins and α/β-unsaturated dicarboxylic acid anhydrides. Specific examples of monoolefins having 2 to 10 carbon atoms include ethylene, propylene, isobutene, 1-butene, 2-butene, 1-pentene, 2-pentene, and 2-methylbutene.
1,2-methylbutene-2, hexene-1,2.
2,4-trimethylpentene-1,2,2,4-
Chain monoolefins such as trimethylpentene-2, decene-1, etc., cyclic monoolefins such as cyclopentene, cyclohexene, cyclooctene, etc., styrene, α-methylstyrene,
Examples include aromatic monoolefins such as vinyltoluene, among which chain monoolefins having 4 to 6 carbon atoms are preferred. In addition, a distillate whose main components are paraffins and monoolefins after separating conjugated diolefins such as butadiene, isobrene, and cyclopentadiene from the C ₄ fraction and C ₅ fraction obtained by naphtha decomposition etc. may be used. However, in this case, the formation of deposits is particularly severe due to the influence of a small amount of remaining conjugated diolefin, so the effect produced by the present invention is even greater. On the other hand, the α/β-unsaturated dicarboxylic acid anhydride may be any one commonly used in this technical field, and specific examples thereof include maleic anhydride, itaconic anhydride, citraconic anhydride, etc. Examples include those having 4 to 10 carbon atoms. Among these, maleic anhydride is prized for its reactivity, quality, and economy. Polymerization of monoolefin and α/β-unsaturated dicarboxylic acid anhydride is carried out according to a conventional method in a solvent that does not dissolve the resulting polymer, but at this time, a specific dispersant is present in the polymerization system. It is necessary to encourage them. The dispersant used is an alkenylsuccinic anhydride, which is an adduct of an α-olefin having 20 or more carbon atoms, preferably 20 to 40 carbon atoms, and an α/β-unsaturated dicarboxylic acid anhydride, or its ester, amide, imide, or metal. It is a derivative such as a salt, and alkenylsuccinic anhydride itself is preferred from the viewpoint of performance and economy. Such alkenylsuccinic anhydrides are usually 20 to 70
℃ and a saponification value of 80 to 350 KOHmg/g. and an α/β-unsaturated dicarboxylic acid anhydride at 170 to 200°C. At this time, as the α/β-unsaturated dicarboxylic acid anhydride, those in the same category as the α/β-unsaturated dicarboxylic acid anhydride used as a monomer in the present invention are used, and in particular, maleic anhydride is used. Awarded. In addition, esters of alkenylsuccinic anhydride are
Alkenylsuccinic anhydride can be obtained by esterification according to known methods using monohydric or polyhydric alcohols such as methanol, ethanol, butanol, octanol, stearyl alcohol, ethylene glycol, glycerin, etc. The amide or imide can be obtained by a conventional method using ammonia, methylamine, ethylamine, butylamine, stearylamine, aniline, cyclohexylamine, monoethanolamine, ethylenediamine, etc. Furthermore, metal salts of alkenylsuccinic anhydrides can be easily obtained using alkali metal or alkaline earth metal hydroxides such as sodium hydroxide, potassium hydroxide, magnesium hydroxide, and the like. However, α-olefins with less than 20 carbon atoms
When an alkenylsuccinic anhydride obtained by adding β-unsaturated dicarboxylic anhydride or a derivative thereof is used as a dispersant, it is not preferable because the effect of suppressing the formation of deposits on the walls of the polymerization vessel is insufficient. The amount of the dispersant used is usually 0.1 to 10 parts by weight, preferably 0.3 to 5 parts by weight, per 100 parts by weight of the α/β-unsaturated dicarboxylic acid anhydride used as the monomer. is less effective in suppressing the formation of deposits, and conversely, if the amount is large, it becomes economically disadvantageous. Further, in the present invention, a solvent that does not dissolve the copolymer to be produced is used as a polymerization solvent. Specific examples of such solvents include linear, branched or cyclic aliphatic hydrocarbons such as butane, pentane, hexane, heptane, ligroin, cyclohexane, etc., aromatic hydrocarbons such as benzene, toluene, xylene, etc. Examples include hydrogen, and aliphatic hydrocarbons, particularly aliphatic hydrocarbons having 4 to 6 carbon atoms, are preferred from the viewpoint of safety, ease of separation, and economic efficiency. Moreover, it is also possible to make the monoolefin used as a monomer exist in excess and use it as a polymerization solvent. In the present invention, polymerization is carried out according to a conventional method in the presence of the above-mentioned solvent and dispersant.
Catalysts used in the reaction include organic peroxides such as cumene hydroperoxide, t-butyl hydroperoxide, benzoyl peroxide, diisopropyl peroxydicarbonate, t-butyl peroxypivalate, etc., α・α′- Azobisisobutyronitrile, α・α′-azo-α-
A radical initiator such as an azobis compound such as ethylbutyronitrile, a redox catalyst, etc., and is not particularly limited as long as it is a radical initiator. The amount of such a catalyst used is usually 0.1 to 10 parts by weight, preferably 1 to 5 parts by weight, per 100 parts by weight of the α/β-unsaturated dicarboxylic anhydride. Polymerization is usually carried out at 5 to 150°C, preferably 20 to 120°C.
It is carried out in suspension for 0.5 to 12 hours.
At this time, when using a solvent that does not dissolve α/β-unsaturated dicarboxylic acid anhydride,
It is necessary to polymerize at a temperature higher than the melting point of the α/β-unsaturated dicarboxylic acid anhydride, and it is particularly preferable to polymerize at a temperature higher than the melting point of the dispersant. The charging ratio of monoolefin and α/β-unsaturated dicarboxylic acid anhydride can be selected arbitrarily, but from the viewpoint of reactivity, the amount of monoolefin should be set at 80%.
~40 mol%, preferably 70-50 mol% is suitable. Further, in order to increase productivity, it is preferable to make the monomer concentration as high as possible, and it is appropriate to polymerize at a monomer concentration of 10% by weight or more, more preferably 20% by weight or more. After the polymerization is completed, the produced polymer is separated from the solvent according to a conventional method, and the number average molecular weight is determined.
Approximately equimolar alternating copolymers of about 300 to 50,000 are obtained. According to the present invention, since almost no deposits are observed on the inner walls of the polymerization can or the stirrer, stable operation is possible without cleaning the polymerization can over a long period of time, resulting in high yields. The copolymer can be obtained efficiently at a high rate. Next, the present invention will be explained in more detail with reference to Examples. The _C5 monoolefin fraction used in the examples refers to pentene-1 and pentene-1 obtained by separating conjugated diolefins such as isoprene, 1,3-pentadiene, and cyclopentadiene from the _C5 fraction.
Approximately 40% by weight of monoolefin containing 2,2-methylbutene-1 and 2-methylbutene-2 as main components,
It means a mixture consisting of about 1% by weight of conjugated diolefin mainly composed of 1,3-butadiene, isoprene, 1,3-pentadiene and cyclopentadiene, and about 59% by weight of paraffin mainly composed of n-pentane. , In addition, the numerical values indicating the formation status of deposits in Examples and Comparative Examples refer to the state without deposits.
The evaluation was divided into five stages from (1) to (5) where a large amount of deposits were observed. Furthermore, all parts and percentages in the examples are by weight. Reference Example 1 An equimolar amount of maleic anhydride was added to various α-olefins obtained by polymerizing ethylene, and an addition reaction was carried out in the presence of a polymerization inhibitor to form alkenylsuccinic anhydrides shown in Table 1. Obtained.

[Table] Example 1 196 parts of maleic anhydride, Reference Example 1 as a dispersant
1.0 part of the alkenylsuccinic anhydride (V) obtained in step 1 was placed in a 3L autoclave equipped with a stirrer, and the can was sealed.
Then, after purging the system with nitrogen, isobutylene was added under reduced pressure.
After adding a mixture of 457 parts of cyclohexane and 686 parts of cyclohexane, and further adding 9.8 parts of t-butylperoxypivalate, the temperature was raised to 75°C, and the mixture was heated and stirred at the same temperature for 3 hours to carry out a polymerization reaction. The condition inside the autoclave after the completion of the polymerization reaction was at stage (1), with almost no deposits observed on the inner walls or stirring blades. The conversion rate of maleic anhydride in this reaction is 83.0%
Since no deposits were formed, the yields based on maleic anhydride were approximately the same. Comparative Example 1 Polymerization was carried out according to Example 1 except that no dispersant was used, and the conversion rate of maleic anhydride was 43.9%, but the amount of deposits formed was extremely large (5). Because of the heat, the desired copolymer could hardly be obtained. Example 2 196 parts of maleic anhydride, Reference Example 1 as a dispersant
Various alkenylsuccinic anhydrides [()~
()] 1.0 part was charged into a 3L autoclave equipped with a stirrer, the can was sealed, and the inside of the system was purged with nitrogen. 1143 parts of _C5 monoolefin fraction was added under reduced pressure, and further t-butyl peroxypivalate was added. After adding 9.8 parts, the temperature was raised to 75°C, and the mixture was heated and stirred at the same temperature for 3 hours to effect polymerization. After the polymerization reaction was completed, the yield of the produced copolymer was measured, and the formation of deposits on the walls of the polymerization vessel was observed. The results are shown in Table 2.

[Table] From the results, it can be seen that in the case of the examples of the present invention, the yield was high and, moreover, the formation of deposits was hardly observed. However, when alkenyl succinic anhydride obtained by adding α/β-unsaturated dicarboxylic acid anhydride to α-olefin with a small number of carbon atoms is used as a dispersant (Experiment No. 2.3 and 4),
The effect of suppressing the formation of deposits is not necessarily sufficient. Example 3 Derivatives of alkenylsuccinic anhydride ( ) obtained in Reference Example 1 were used as dispersants, namely esterified products with ethyl alcohol [copolymer ( )] and esterified products with n-butyl alcohol [copolymer ( )]. )] and an amidated product with diethylamine [copolymer (2)] was used. After the polymerization reaction was completed, the yield of the produced copolymer was measured, and the state of adhesion to the wall of the polymerization vessel was observed. The results are shown in Table 3.

[Table] Example 4 Example 1 except that 1.0 part of the alkenylsuccinic anhydride () obtained in Reference Example 1 was used as the dispersant and 343 parts of cyclopentene was used as the monoolefin.
When an experiment was conducted in the same manner as above, the conversion rate of maleic anhydride was 68.0%, and no deposits were observed.

Claims (1)

[Scope of Claims] 1. When radical copolymerizing a monoolefin having 2 to 10 carbon atoms and an α/β-unsaturated dicarboxylic acid anhydride in a solvent that does not dissolve the produced polymer, a dispersant having 20 or more carbon atoms may be used as a dispersant. α-olefin to α・
A monoolefin-α/β-unsaturated dicarboxylic anhydride copolymer characterized in that an alkenylsuccinic anhydride or a derivative thereof obtained by addition of a β-unsaturated dicarboxylic anhydride is present in the polymerization system. manufacturing method. 2. The method according to claim 1, wherein the dispersant is an alkenylsuccinic anhydride obtained by adding an α/β-unsaturated dicarboxylic acid anhydride to an α-olefin having 20 to 40 carbon atoms. 3. The method according to claim 2, wherein the alkenylsuccinic anhydride has a contact point of 20 to 70°C and a saponification value of 80 to 350 KOHmg/g. 4. The method according to claim 1, wherein the solvent is an aliphatic hydrocarbon. 5. The method according to claim 1, wherein the α/β-unsaturated dicarboxylic acid anhydride used as the monomer is maleic anhydride. 6. The method according to claim 1, wherein the amount of the dispersant used is 0.1 to 10 parts by weight per 100 parts by weight of the α/β-unsaturated dicarboxylic anhydride.