JPS5823803A - Preparation of copolymer - Google Patents

Abstract

PURPOSE:To obtain a copolymer havng excellent transparency, heat resistance, etc., continuously, in high efficiency, by adding a maleic acid half eter dividedly to an aromatic vinyl compound, copolymerizing the mixture, and cyclizing the maleic acid half ester unit by removing alcohol therefrom. CONSTITUTION:40-2wt%, preferably 30-50% maleic acid half ester (e.g. monomethyl maleate) is added to 60-98%, preferably 70-95% aromatic vinyl compound (e.g. styrene) in >=2 lots, preferably 2-5 lots, and the mixture is copolymerized by continuous bulk polymerization, etc. The maleic acid half ester in the copolymer is cyclized by removing alcohol therefrom, e.g. by vacuum drying, etc. to obtain the objective copolymer. The content of themaleic acid unit in the obtained copolymer can be adjusted arbitrary in the range of >=40%.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a copolymer, and more specifically to a method for producing a styrene-based copolymer, which is capable of carrying out bulk continuous polymerization which is industrially advantageous and has excellent production efficiency, and which also has excellent transparency and heat resistance. The present invention relates to a method for obtaining a copolymer of.

Generally, styrene-maleic anhydride copolymer is known as a styrene-based resin with excellent heat resistance. However, the copolymerization reaction of aromatic vinyl compounds such as styrene with maleic anhydride Due to its high reactivity, alternating copolymers are likely to form, and it is impossible to produce a uniform and useful copolymer with the content of maleic anhydride units within a specified amount using the energizing method. As a method for producing such a useful copolymer, (1) copolymerizing 5 to 40% of styrene and maleic anhydride by bulk polymerization, and after substantially completing the copolymerization with maleic anhydride. , Method of transferring to suspended heavy metal
19914) and a method of adding methyl methacrylate as a fifth component when copolymerizing styrene and maleic anhydride (Japanese Patent Publication No. 5S-1O26341).

However, in the above (!) method, anhydrous! The result is a mixture of a very high styrene content and a styrene homopolymer obtained by suspension polymerization, resulting in low heat resistance and poor transparency, and the copolymer precipitates during bulk polymerization, resulting in non-uniformity. There are drawbacks to it. On the other hand, in the method described above, since methyl methacrylate is essential as the fifth component, a styrene-maleic anhydride copolymer cannot be obtained, but a different type of copolymer is obtained.

Therefore, the present inventors have devised a method that overcomes the drawbacks of the above-mentioned conventional techniques and allows for the continuous and efficient production of styrenic copolymers with excellent physical properties, particularly transparency and heat resistance, using simple operations. After much research and development, we were able to achieve the goal by using maleic acid half ester instead of maleic anhydride and adding it to the reaction system in two or more stages. The present invention was completed based on this knowledge.

That is, the present invention applies to aromatic vinyl compounds! Copolymerized by adding leicic acid bovine ester in two or more stages,
- Provides a method for producing an aromatic vinyl compound-maleic anhydride copolymer, which is characterized in that the maleic acid half ester unit is then dealcoholized and cyclized.

The aromatic vinyl compound used in the present invention is the main raw material of the resulting copolymer, and specifically includes styrene, α-methylstyrene, dimethylstyrene, diethylstyrene, monocourostyrene, SiOa styrene, vinyl Examples include toluene or a mixture thereof.

Furthermore, the maleic acid half ester to be copolymerized with the above-mentioned aromatic vinyl compound is a monoester in which an alcohol having about 1 to 8 carbon atoms is added to maleic anhydride. It can be obtained by adding at a ratio of Specifically, monomethyl maleate, monoethyl maleate,! No amount of leic acid - provil.

! Examples include monobutyl leate.

In the method of the present invention, in copolymerizing the above-mentioned aromatic vinyl compound and maleic acid half ester,! If the leicic acid ester is added in two or more steps, the reaction will not proceed vigorously, but it will still occur in the early stages of the polymerization reaction. A copolymer with a high content of leic acid cow ester grows, and its content gradually decreases, until finally a homopolymer of aromatic vinyl compounds is produced, and a mixture of these forms, resulting in poor transparency. You can only get things. Note that if maleic anhydride is added instead of maleic acid half ester, the copolymerization reaction will proceed rapidly, making it extremely difficult to control the reaction.
Maleic anhydride has to be added sequentially in small quantities, but as in the method of the invention! When using Rhein-cow ester, the desired copolymer can be obtained by dividing it into about 2 to 100% of the copolymer, and its transparency and heat resistance will be sufficient.

When adding the maleic acid half ester in portions as described above, the same amount may be added at each stage, or the amount added may be gradually reduced.

In the method of the present invention, the ratio of the above-mentioned aromatic vinyl compound and maleic acid half ester to be used is not particularly limited and may be appropriately selected depending on the physical properties of the desired copolymer. is set to 60 to 98 weight arc, and the total amount of maleic acid half ester to be added in portions is set to 40 to 2% by weight. Particularly preferably aromatic vinyl compounds 70-9
5 weight attack! Rein half ester sO should be about 5% by weight.

In the present invention, other vinyl compounds can also be added if necessary. Specifically, Ak9w nitrile,
Examples include meta-arynitrile, acrylic acid, acrylic esters, and methacrylic esters. There is no particular limit to the amount of this vinyl compound used, but
Normally, the amount may be determined within a range of 40 parts by weight or less based on 100 parts by weight of the total amount of the aromatic vinyl compound and '4' ester maleic acid.

Further, in the method of the present invention, a catalyst or a polymerization regulator may be appropriately added to the reaction system to promote the polymerization reaction or to control the degree of polymerization. As a catalyst, a radical generator is usually used, specifically an organic peroxide such as cytamyl peroxide, lauroyl peroxide, benzoyl peroxide, or an azo polymerization initiator such as azobisisobutytetranitrile. and so on. On the other hand, examples of polymerization regulators include mercaptans. Further, in order to impart impact resistance, a rubber component such as prbutadiene may be added to the reaction system for polymerization.

Furthermore, in the method of the present invention, since the reaction proceeds sufficiently by bulk polymerization, a medium such as water or an organic solvent is not necessarily required for the reaction, but it is possible to add a small amount of solvent or to perform solution polymerization. You can also do that.

Examples of solvents used in this WItI11 polymerization include acetone, methylethylchloride, and the like. Suitable are aromatic compounds such as silene and benzene, or p-thalene, and the like.

In the method of the present invention, an aromatic vinyl compound is added to the reaction system, and if necessary, other vinyl compounds, a catalyst 1 polymerization moderator, a rubber component, or a solvent are added, and then maleic acid semiconducting is added at appropriate intervals. Add the ester in portions. Of course, it is possible to add a portion of the maleic acid half ester to the reaction system from the beginning, but if the entire amount used is added to the reaction system from the beginning, the object of the present invention cannot be achieved as described above. become unable.

The reaction conditions are not particularly limited and may be selected as appropriate, but are usually 50 to 180°C, preferably 70 to 160°C.
℃, and various types of polymerization such as bulk polymerization and solution polymerization are possible. Further, it may be performed by either a continuous method or a patch method. In particular, the method of the present invention relies on continuous, cyclic polymerization, and allows the reaction to proceed extremely efficiently.

According to the method of the present invention as described above, first, aromatic vinyl roux! A leunic acid half ester co-compound is obtained. Then, the obtained aromatic vinyl-! Leic acid half ester copolymer,
7 latshear, thin cloud evaporation a.

Using an extruder, etc., the copolymer is dried under pressure, heated and melted, and then treated with alcohol. Anhydrous by cyclizing the leic acid half ester unit! Converts to leic acid units. Ill take it! ! If the process is carried out, an aromatic vinyl-maleic anhydride copolymer with extremely excellent transparency and heat resistance can be obtained.

As described above, the method of the present invention does not add reaction raw materials sequentially, but only by dividing them into 2 to 5 stages.
Since the desired copolymer can be obtained, the process is easy to operate and requires simple equipment, making it an extremely industrially advantageous method. Furthermore, since continuous bulk polymerization is possible and there is no precipitation of lumber during polymerization, the pole-forming efficiency is extremely high. Moreover, the resulting copolymer is anhydrous! Since the content of leic acid units can be arbitrarily adjusted within the range of 40 or less, it is anhydrous aromatic vinyl with excellent quality, heat resistance, and melt flowability depending on the purpose of use.
Maleic anhydride copolymer.

The copolymer thus obtained is an industrial material.

It can be effectively used as a building material or packaging material.

Next, the present invention will be explained in more detail from Example 7.
, Y mono-l-butyl oleate 159.5).

Sitacel peroxide t56? and Silen 220t
was charged, and the reaction was carried out at 117°C for S hours. The conversion rate in this first stage was 50%. Next, let's move on to this reaction system! Reic acid monoho-butyl 8 & 5? was added and the reaction was continued for 6 hours.

Thereafter, the reaction product was purified by reprecipitation in petroleum ether and dried under reduced pressure to obtain a styrene-maleic acid-butyl copolymer. The final conversion rate was 8. whisper. Subsequently, this copolymer was fed to a pent extruder at 2i50°C, where it was dealcoholized to give the copolymer a! Anhydrous by cyclizing leic acid mono-butyl units! Converted to leicic acid units, styrene-anhydrous! A leic acid copolymer was obtained (
IR conversion-85 attack ~ The properties of this product are shown in Table 1.

Example 2 Styrene 124Q,
! Monobutyl leate 112.7f.

Cytamyl peroxide t 56 fo and toluene 2
20f was charged and the reaction was carried out at 117°C for 2 hours.

The conversion rate in this first stage was 30%.0 Then in this reaction system! Reaction was continued for 3 hours by adding mono-1-butyl BL4F.

The conversion rate up to this second stage was 50%. moreover,
In this reaction system! Rhein rIII so)-1-butyl Is
Table 4 was added and the reaction was continued for 5 hours.

Thereafter, the reaction product was purified by reprecipitation in petroleum ether, and dried to remove styrene. A monobutyl leic acid copolymer was obtained. The final conversion rate was 82 arcs. Subsequently, this copolymer was dealpooled in a vacuum drying chamber of 210"e to cyclize the !rain!mono-3-butyl units in the copolymer and convert them into maleic anhydride units, resulting in styrene-maleic anhydride. An acid copolymer was obtained (conversion rate 100%)
). The properties of this product are shown in Table 1.

Example S Styrene 1240f was placed in a complete mixing reactor with an internal volume of 2t.
, 2 f of monomethyl leate, 56 g of cytamyl peroxide, and 220 f of toluene were heated at 117°C.
The reaction was carried out for 2 hours.

The conversion rate in this first stage was 28%.Next, monomethyl maleate 6L4f was added to this reaction system, and the reaction was continued for 2 hours. The conversion rate at this 28 m weight is 52%
Met. Furthermore, this reaction system! 42.8 f of monomethyl leate was added and the reaction was continued for 55 hours. Thereafter, the reaction product was purified by reprecipitation in petroleum ether and dried under reduced pressure to obtain a styrene'''!monomethyl oleate copolymer.The final conversion rate was 81%.Subsequently, this copolymer + The body is dealcoholized in a vacuum dryer at 1oC to cyclize the monomethyl units in the copolymer and make it anhydrous!
Converted to leic acid unit, styrene-anhydride! A leic acid copolymer was obtained (conversion rate: 100j9°). The properties of this product are shown in Table 1.

Reference example 1 1240 tons of styrene was placed in a complete mixing reactor with an internal volume of 2 tons.
, mono-butyl maleate 24 B reshita tiger rubber oxide t56? and 220f of toluene were charged, and the reaction was carried out at 117°C for 5 hours.Then, the reaction product was purified by reprecipitation in petroleum ether, dried under reduced pressure, and styrene-! A monobutyl leic acid copolymer was obtained. The conversion rate was 45 times. Subsequently, this copolymer was added to 210
'C dealcoholization in the vacuum drying mouth of the copolymer!
Leic acid mono-ho - Anhydrous by cyclizing the butyl unit! Converted to leic acid unit, styrene-anhydride! A leic acid copolymer was obtained (conversion rate 100%).

The properties of this product are shown in Table 1.

Example 4 Internal volume! Styrene 12403 was added to the complete mixing reactor of t.
F, -rmono-n-butyl leate 10A7P was charged, and the reaction was carried out at 140°C for t5 hours.

The conversion rate in this first stage was 31 cases. Next, mono-■-butyl maleate 7&O? is added to this reaction system. was added and the reaction was continued for 2 hours. The conversion rate up to this second stage was 63%. Furthermore, mono-A-butyl maleate 52.1) was added to this reaction system, and the mixture was heated at 150°C.
The reaction continued for hours.

The final conversion was 81%. Then the reaction product is 21
Vacuum dry at 0°C and leave nothing behind! At the same time as removing -,
Dealcoholized and copolymerized! Anhydrous by cyclizing monobutyl units of leic acid! Convert to leic acid unit 1. Styrene - anhydride! A leic acid copolymer was obtained (conversion rate 100%). The properties of this product are shown in Table 1.

Comparative Example 1 The same operation as in Reference Example 1 was carried out except that the reaction time was changed to 10 hours, and styrene-! A mono-butyl leic acid copolymer was obtained.

Subsequently, this copolymer was dealcoholized in the same manner as in Reference Example 1, resulting in styrene-anhydride! A rheological copolymer was obtained (conversion rate 100%\The properties of this product are shown in Table li1.

Comparative Example 2 In Comparative Example 1,! Instead of Mono A-Butyl Leate! A styrene-maleic monomethyl copolymer was obtained at a conversion rate of 80% by carrying out the same operation as in Comparative Example 1, except that monomethyl leate was used, and then Comparative Example 1.
Dealcoholize in the same manner as styrene - anhydrous! Table 1 shows the properties of the obtained copolymer of leic acid (conversion rate: 100-).

Reference example 2 1. In a stainless steel reactor with a capacity of 201. Stille ( 100Of of water was charged, and stirring was started at 70°C.

Then, in this reactor, anhydrous! Rain @5ooy.

A mixture of azobisisobutysilyl 10) and methylethyl + syn 5oooy was added continuously at a rate of 91 Lt/min for 5 hours, then at 49-7 minutes for 4 hours, and then at L5-7 minutes for tS time, and the reaction was continued. I did it. Thereafter, the reaction product was poured into petroleum ether, the copolymer was recovered and dried under reduced pressure, and the styrene-anhydrous! A leic acid copolymer was obtained. The properties of this item are shown in the first review.

Note φ Commercially available general-purpose polystyrene...Measuring at a temperature of 250°C and a load of 2160P...Measurement at a pressure of 1 & 6 Yu/a1 From the above results, the following can be seen. That is, reference example 1
Although this is a one-stage reaction, since the reaction time is short, the result is almost the same as when the method of the present invention is stopped at one stage. However, although the physical properties of the obtained copolymerization are good, the conversion rate is low, so it is poor in practical use. Further, in Reference Example 2, since maleic anhydride is used, additions must be made sequentially, making the operation complicated. On the other hand, in Comparative Example 19.2, the resulting copolymer had very low transparency, and in Comparative Example S, the tensile strength and heat resistance were low. In contrast, in Examples 1 to 5, although the operations were relatively simple, the conversion rates were high, and the resulting copolymers had excellent transparency and heat resistance.

Procedural amendment (voluntary) September 7, 1980 Director General of the Japan Patent Office Shima 1) Indication of Haruki-dono's case Patent application No. 5S-121879 1 Name of the invention Relationship with the person making the amendment to the process for producing a copolymer Patent applicant Idemitsu Kosan Co., Ltd. 4th agent 〒1.3 Contents of column amendments to the detailed explanation of the invention in the specification (1) “0, pressure t & 5k” on page 18, line S of the specification
"Measure at II/csl" is corrected to "Measure at 0.1 fLdk1/m j.

(2) "Examples 1-5" on page 18, line 14 is corrected to "Examples 1-4."

(that's all)

Claims (1)

[Claims] 0) A maleic acid half ester is added to an aromatic vinyl compound.
1. A method for producing an aromatic vinyl compound-maleic anhydride copolymer, which comprises adding weights in multiple stages to cause a copolymerization reaction, and then dealpooling the maleic acid half ester units to cyclize them. (2) The method according to claim 1, wherein the maleic acid half ester is added in two or more stages in a total of 40 to 2 parts by weight to 60 to 98 parts by weight of the aromatic vinyl compound. (3) Addition of maleic acid half ester in 2 to 5 portions
The method according to claim 1!11 or 2, which is a step. (41) The method according to claim 1, wherein the copolymerization reaction is continuous bulk polymerization.