JPH10130325A - Production of halogenated styrene polymer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simply and economically obtain the subject polymer of highly halogenated styrene excellent in thermal stability in a high yield by using a reaction product between a Lewis acid and a nucleophilic substance as a polymerization catalyst in one reaction solution. SOLUTION: (A) unsaturated monomers comprising (i) 50-100wt.% of styrene monomer and (ii) 0-50wt.% of a monomer cationically copolymerizable with the styrene monomer are polymerized in the presence of (B) a catalyst and (C) the styrene polymer product is halogenated. In this case, (B) the polymerization catalyst is prepared by reaction of (iii) a Lewis acid represented by the formula [Me is a tri- or tetravalent metal atom; X is a halogen; R is H, a 1-6C alkyl, an aliphatic amine; a is 3, 4, (a-x)/x is 0-999] with (iv) a nucleophilic substance, used in an amount of 0.001-10 pts.wt. per 100 pts.wt. of the component A to effect cationic polymerization. Then, the resultant styrene polymer is halogenated using a Lewis acid as a halogenation catalyst in an amount of 0.01-20 pts.wt. per 100 pts.wt. of the styrene polymer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a halogenated styrene polymer having excellent heat stability by cationically polymerizing styrene and then halogenating the styrene with a halogenating agent. .

[0002]

2. Description of the Related Art Brominated styrene polymers can be produced by a method of polymerizing a brominated styrene monomer and a method of brominating a styrene polymer.
However, all known methods of this kind have various difficulties and disadvantages.

[0003] Styrene polymers are generally obtained in high molecular weight by radical polymerization. When a high molecular weight styrene polymer is brominated, the polymer backbone is attacked, resulting in a significant change in viscosity. Thus, for example, when the bromine content is greater than 20% when brominated using a Lewis acid catalyst, the product is obtained in a strongly colored, swollen or crosslinked state, and in fact the required light-colored, heat-stable product Can not be processed.

[0004] According to FR-A-1245832 it is stated that only products having a bromine content of less than about 10% by weight and a low thermal stability can be obtained, which products are of practical use. Had no significance.

According to JP-A-53-60986,
The styrene monomer is polymerized using a Lewis acid catalyst, and then, if desired, an additional amount of Lewis acid is added to carry out a bromination reaction. According to this method, a product having a bromine content of about 50 to 70% by weight can be obtained, but only a product having low thermal stability can be obtained. This product has practical significance. Did not.

According to Japanese Patent Application Laid-Open No. 61-34723,
If a nucleophilic substance acting as a base for a Lewis acid, such as water, is added in an appropriate range and brominated, a substance having good thermal stability can be obtained, but a molecular weight of 50,000 to 500,000.
Since polystyrene No. 00 is used, the brominated product has a high molecular weight, has a high viscosity at the time of melting, and has a drawback of lacking fluidity.

All known processes for the direct bromination of styrene polymers have given rise to products with low and poor thermal stability. Or, even if the thermal stability is good,
Only products with insufficient flow were obtained.

On the other hand, the polymerization of nuclear brominated styrene is described, for example, in German Patent No. 1570395. This method has the disadvantage that it has to be carried out in a number of steps and, correspondingly, requires a great deal of equipment expense.

[0009]

The present inventors have previously reacted a Lewis acid with a nucleophilic substance, cationically polymerize styrene using the reactant as a catalyst, and subsequently obtained a polymerized product of bromine. The present inventors have found that this problem can be solved by the conversion, and have reached the present invention.

[0010]

According to the present invention, an unsaturated monomer comprising 50 to 100% by weight of a styrene monomer and 0 to 50% by weight of a monomer capable of cationic polymerization with a styrene monomer is used as a catalyst. A method for halogenating a styrene polymer obtained by polymerization in the presence of a polymer, wherein the catalyst is a polymerization catalyst comprising a Lewis acid represented by the following general formula (1) and a nucleophilic substance; 0.001 to 20 parts by weight of a Lewis acid as a halogenation catalyst is used per 100 parts by weight of a styrene polymer obtained by cationic polymerization in the presence of 0.001 to 10 parts by weight of the catalyst per 100 parts by weight of a monomer. The present invention provides a method for producing a halogenated styrene polymer, wherein the method comprises halogenating using a styrene polymer.

[0011]

Embedded image

[Where Me is a trivalent or tetravalent metal atom, X is a halogen atom, R is hydrogen, and has 1 to 6 carbon atoms.
A linear or branched alkyl group and an aliphatic amine group,
a is 3 or 4, and (ax) / x is 0 to 999. Hereinafter, the present invention will be described in detail. As a catalyst in the polymerization reaction of the present invention, a reaction product of a Lewis acid and a nucleophile is used. As the Lewis acid used, a metal halide is particularly used, and examples thereof include aluminum chloride, aluminum bromide, ferric chloride, antimony chloride, antimony bromide, copper chloride, copper bromide, and tetrachloride. Tin, titanium tetrachloride, zinc chloride and the like can be mentioned, preferably chlorinated or brominated metal, and particularly preferably aluminum chloride.

As the nucleophilic substance as a catalyst, at least one compound selected from the group consisting of aliphatic alcohols and aliphatic amines having 6 or less carbon atoms is used, and aliphatic alcohols are particularly preferably used. Such as, for example, hexanol, branched isopropanol, t
At least one compound selected from the group consisting of -butanol, n-butanol, n-propanol, ethanol and methanol, and the like, and preferably n-butanol. The amount of the nucleophilic substance is 0.001 to 100% by weight of an unsaturated monomer comprising 5 to 100% by weight of a styrene monomer and 0 to 50% by weight of a monomer capable of cationic polymerization with the styrene monomer. 10 to 10% by weight, preferably 0.01 to 3% by weight. If the amount is less than 0.001% by weight, the polymerization rate becomes extremely slow, which is not preferable.
If it exceeds 10% by weight, the production of oligomers increases, which is not preferable. The catalyst may be added all at once to the reaction system, but by adding it in portions, the polymerization yield is increased in a short time and the residual amount of unreacted monomer at the end of polymerization is significantly reduced. Is preferred.
Alternatively, they may be diluted and added to the same reaction solvent as used in the present invention or another solvent inert to the reaction.

Examples of the polymerization solvent include halogenated hydrocarbons such as dichloromethane, chloroform, carbon tetrachloride, dichloroethane, tetrachloroethane and tetrachloroethylene, which do not deactivate the catalyst, nitrobenzene and nitromethane.

The aliphatic alcohol which is a nucleophilic substance contained in the solvent is, for example, hexanol, branched isopropanol, t-butanol, n-butanol, n-propyl alcohol, ethanol, methanol or the like. A suitable amount is from 0.03 to 3.0 moles per mole of acid. If the amount of the nucleophilic substance is less than 0.03 mol with respect to the Lewis acid, the degree of polymerization will not be increased, so that it is not preferable.

The ratio of the solvent to the unsaturated monomer used in the polymerization of the present invention is not particularly limited, but in consideration of the control of the reaction system and the post-treatment step, the ratio of the solvent to the unsaturated monomer is not considered. The ratio is in the range of 30/70 to 95/5, more preferably 50/50 to 80/20 by weight. If the ratio of the solvent to the unsaturated monomer is less than 30/70, gelation occurs and the halogenation becomes non-uniform, while if it is more than 95/5, productivity is poor and it is not practical.

In the present invention, the styrene monomer can be used alone or as a mixture with another monomer that can be cationically copolymerized with stin, for example, an unsaturated monomer. Examples of monomers that can be cationically copolymerized with styrene include isobutylene or nucleus-alkylated styrene such as vinyl toluene, vinyl ethyl benzene, or vinyl propyl benzene. These monomers can be used in amounts of up to 50% by weight, preferably 5 to 20% by weight, based on the mixture of styrene and all monomers. It is particularly preferred to use styrene alone.

The polymerization catalyst is preferably prepared by charging a predetermined amount of a Lewis acid and a nucleophile serving as a base in a predetermined amount of a volumetric flask, and adjusting the polymerization solvent with the same reaction solvent as used in the present invention. In the polymerization reaction, usually, a predetermined amount of a solvent and a monomer are charged,
This can be adjusted to a predetermined polymerization temperature, and then the catalyst can be added all at once to carry out the reaction. After the addition of the catalyst system, the polymerization is terminated by allowing the reaction to proceed for a long time. However, the catalyst can be dividedly added in the course of the reaction to accelerate the termination of the polymerization.

The polymerization temperature is usually -20 to 50 ° C.
Is suitable, preferably, -10 to 40 ° C,
More preferably, the range of -5 to 30C is appropriate.
When the polymerization temperature is lower than −20 ° C., the reaction rate is low, so that it is not industrially suitable. On the other hand, if the temperature is higher than 50 ° C., it is not appropriate because oligomers are easily generated.

The polymerization time cannot be uniquely defined because it depends on the polymerization temperature, the amount of the catalyst, the method of adding the catalyst, and the like.
8 hours. When the polymerization time is shorter than 3 hours, the residual unsaturated monomer becomes 1% or more, which causes deterioration of thermal stability. On the other hand, when the polymerization time is longer than 8 hours, the residual styrene is less than 1%, so that a further polymerization time is substantially unnecessary.

The styrene polymer of the present invention obtained by such polymerization has a weight average molecular weight of 1,000 to 10
It is in the range of 0.000 and the residual unsaturated monomer is 5% by weight or less, preferably 1% or less. When the weight average molecular weight is less than 1,000, thermal stability is poor, while 100,
If it is larger than 000, gelation occurs and a non-uniform halide is formed, which is not preferable. Although the polymerization product of the present invention may show a broad molecular weight distribution, it can be preferably used for halogenation described later.

The halogenation of the present invention is characterized in that the halogenation is carried out directly after the polymerization without isolating the polymerization product from the polymerization reaction solution. Such a halogenation reaction is generally performed as follows. After the Lewis acid is additionally added to the solution of the polymerization product of styrene obtained in the first operation step, the halogenating agent is gradually added. The concentration of the polymerization product in the reaction solution in the halogenation is preferably 5 to 40% by weight. 5% by weight of polymerization product
If it is lower than this, productivity is poor and it is not practical. Meanwhile, 4
If the content is higher than 0% by weight, gelation occurs and non-uniform halogenation occurs.

The amount of the Lewis acid catalyst additionally added to the unsaturated monomer polymerization reaction solution of the present invention is generally 0.000.00 parts by weight based on 100 parts by weight of the styrene polymer contained in the reaction solution.
It is 1 to 20 parts by weight, preferably 0.1 to 10% by weight. If the amount is less than 0.001% by weight, the polymerization rate becomes extremely slow, which is not preferable. If the amount is more than 20% by weight, the formation of oligomers increases. , Iron (III) chloride, antimony (III) chloride,
And tin tetrachloride. Aluminum halides are particularly preferred. The amount of Lewis acid catalyst used is determined in particular by the desired molecular weight of the polymer and the styrene polymer 1
It is generally 0.001 to 20 parts by weight, preferably 0.1 to 10 parts by weight, based on 00 parts by weight. When the amount is more than 20 parts by weight based on the total amount of the monomers to be polymerized, the heat stability of the obtained polymer is deteriorated, and when it is less than 0.001%, the halogen content is less than 40% by weight. This product has no practical significance.

The reaction temperature of the halogenation is usually-
The range of 20 to 50 ° C is suitable, but preferably -10 to
40 ° C, more preferably -5 to 20 ° C is appropriate. When the reaction temperature for halogenation is lower than -20 ° C, the reaction product gels. On the other hand, when the temperature is higher than 50 ° C., the thermal stability of the product deteriorates.

The amount of halogenating agent used is determined by the desired halogen content of the target product. Practically, a styrene polymer containing 40 to 80% by weight, preferably 50 to 70% by weight of halogen based on the halogenated styrene polymer is desirable. When the halogen content is lower than 40% by weight, the amount added to the resin increases, and the physical properties of the resin deteriorate. On the other hand, if it is higher than 80% by weight, the product is crosslinked or only a product having poor heat stability is obtained.

In order to complete the halogenation reaction, stirring can be further performed after the addition of the halogenating agent is completed. The halogenation reaction time is usually 10 to 120 minutes, preferably 20 to 60 minutes. If the halogenation reaction time is shorter than 10 minutes, it becomes difficult to control the cooling. On the other hand, when the time is longer than 120 minutes, a side reaction occurs to deteriorate the thermal stability of the product.

Generally, after the halogenation reaction, water is usually added to inactivate the catalyst. At this time, it is desirable to add a reducing agent such as Na ₂ S ₂ O ₃ or NaHSO ₃ . Next, it is finally necessary to wash with an aqueous alkali solution and then with pure water until substantially no halogen ions are contained. Examples of the alkali include sodium hydrogen carbonate, sodium carbonate, calcium hydroxide, and sodium hydroxide. However, the target substance can be recovered by appropriately selecting the amount of the halogenating agent and the catalyst concentration. From the washed reaction solution, a halogenated product can be isolated by a known method. In this case, the solvent is preferably removed by evaporating and concentrating the reaction solution. For example, a solid product is obtained by removing the solvent by spray drying. Like this
Continuous finishing with a short residence time of the product is especially
preferable.

Examples of the halogenating agent used in the halogenation reaction include chlorine, bromine and iodine.
More than one species may be used. Among them, a halogenating agent containing bromine as a main component is preferable because the amount of by-products is small and the generated halogenated styrene polymer has high flame retardancy. Further, the bromine content is 100% by weight of the total halogenating agent. Of these, 90% by weight is preferred, and most preferably 98% by weight or more.

[0029] The brominated styrene polymerization product produced by the process of the present invention has high thermal stability. The polymerization product is a white to pale yellow solid, even at high bromine contents up to about 70% by weight. The brominated styrene polymerization product produced according to the present invention is 240-3
Even at 40 ° C., there is almost no decomposition or discoloration.

[0030]

EXAMPLES The present invention will be described more specifically with reference to the following Examples and Comparative Examples, which do not limit the present invention.

The polymerization products obtained in Examples and Comparative Examples were measured for the residual monomer content and weight average molecular weight (Mw), and the brominated product was measured for APHA, thermogravimetric analysis, and bromine content. Table 1 shows the measurement results.

The residual monomer, weight average molecular weight, A
PHA, thermogravimetric analysis, and measurement of bromine content were performed according to the following methods.

1) Analysis of residual unsaturated monomer Analysis was performed by gas chromatography (GC).

2) Weight average molecular weight (Mw) Measured by gel permeation chromatography (GPC) using standard polystyrene. Column: Shodex A-804 manufactured by Tosoh Corporation 3) APHA A 0.1 g sample was heat-treated at 280 ° C. for 25 minutes, cooled to room temperature, dissolved in 50 ml of methylene chloride, and dissolved.
Take 50 ml of a flat bottom test tube, and use the same volume of the Hazen Color Standard Standard Solution and a daylight fluorescent lamp to visually compare the color from above with the naked eye. Select the color number standard solution corresponding to the sample and use it as the color number of the sample.

4) Thermogravimetric Analysis A 3% weight loss onset temperature was measured using a thermobalance at a heating rate of 20 ° C./min. 5) Analysis of bromine content The bromine content was analyzed by the Calius method.

Example 1 A 25 ml volumetric flask was charged with 10 ml of methylene chloride first, and 7.57 × 10 ⁻³ mol of aluminum chloride as a catalyst. The temperature in the system was adjusted to about 20 ° C. While slowly cooling the volumetric flask to 7.57 × 10 ⁻³ n-butanol.
mol (mole ratio 1/1). After the reaction between aluminum chloride and n-butanol is completed, methylene chloride is further charged, and the total volume is adjusted to the mark of 25 ml.
This solution is referred to as solution A.

In a 250 ml volumetric flask, add 7.8.
After styrene is charged to 5% by weight, methylene chloride is further charged, and the total volume is adjusted to the 250 ml mark. This solution is referred to as solution B. 500ml capacity
Attach a stirrer and thermometer to the four-necked flask. 280 g of the solution B is charged into the reaction vessel, and the reaction system is cooled to about −2 to 3 ° C. while stirring. Thereafter, 4.71 g of solution A is further added as a catalyst to carry out a polymerization reaction. While maintaining the reaction solution at −2 to 3 ° C., the solution A
Was added three times every two hours at a time, and the mixture was reacted for 2.5 hours to obtain polystyrene. As a result of analyzing the obtained polystyrene, the residual unsaturated monomer was 0.8%, and the molecular weight of the generated polystyrene (weight average molecular weight, the same applies hereinafter) was 41,300.
After the polymerization time of 5 hours, the temperature of the reaction solution is raised to 5 to 10 ° C., and 0.98 g of aluminum chloride is further supplied.
Subsequently, 89.2 g of bromine was added dropwise over 20 minutes. 30
After a stirring time of minutes, water is added. The catalyst and hydrogen bromide are removed from the organic layer by extracting several times with water.

The purified solution was dropped into 1 L of hot water and the solvent was removed to obtain a solid. The solid product was further filtered off and dried under vacuum at 110 ° C. for 5 hours.
As shown in Table 1, 63.2 g (yield: 95%) of a powder having a bromine content of 67.5% was obtained.

When 0.1 g of this powder was heat-treated at 280 ° C. for 25 minutes, the APHA was 70. The thermogravimetric analysis revealed that the 3% weight loss start temperature was 375 ° C.

Example 2 First, 10 ml of methylene chloride was charged into a volumetric flask having a capacity of 25 ml, and 7.57 × 10 ⁻³ mol of iron chloride was further charged as a catalyst. Then, the temperature in the system was reduced to about 20 ° C. While cooling the volumetric flask, 7.57 × 10 ⁻³ mol (mole ratio 1/1) of methanol is gradually charged while cooling the volumetric flask. After the reaction between iron chloride and methanol is completed, methylene chloride is further charged, and the total volume is adjusted to the mark of 25 ml. The procedure was carried out in the same manner as in Example 1, except that this solution was used instead of Solution A. Table 1 shows the results.

Example 3 First, 10 ml of methylene chloride was charged into a volumetric flask having a capacity of 25 ml, and 7.57 × 10 ⁻³ mol of aluminum chloride was further charged as a catalyst.
Then, while cooling the volumetric flask so that the temperature in the system becomes about 20 ° C., gradually add 2.36 × 1 n-butanol.
0 charged with ^-3 mol (molar ratio 0.3 / 1.0). After the reaction between aluminum chloride and n-butanol is completed, methylene chloride is further charged, and the total volume is adjusted to the mark of 25 ml. The procedure was carried out in the same manner as in Example 1, except that this solution was used instead of Solution A. Table 1 shows the results.
Shown in

Example 4 First, 10 ml of methylene chloride was charged into a 25 ml volumetric flask, and 7.57 × 10 ⁻³ mol of aluminum chloride was further charged as a catalyst.
Subsequently, while cooling the volumetric flask so that the temperature in the system becomes about 20 ° C., gradually n-butanol 1.89 × 1
0 ^-2 mol (molar ratio 2.5 / 1.0) is charged. After the reaction between aluminum chloride and n-butanol is completed, methylene chloride is further charged, and the total volume is adjusted to the mark of 25 ml. The procedure was carried out in the same manner as in Example 1, except that this solution was used instead of Solution A. Table 2 shows the results.
Shown in

Example 5 A 250 ml volumetric flask was charged with 24.8 g (95.8 wt%) of styrene monomer and 1.1 g (4.2 wt%) of vinyl toluene, and further charged with methylene chloride. , With a total volume of 250
Align to the ml mark. The procedure was performed in the same manner as in Example 1 except that this solution was used in place of the solution B. Table 2 shows the results.

Example 6 A 250 ml volumetric flask was charged with 25.0 g (95.8 wt%) of a styrene monomer and 1.1 g (4.2 wt%) of vinylethylbenzene, and further charged with methylene chloride. , The total volume is 2
Align with the 50 ml mark. The procedure was performed in the same manner as in Example 1 except that this solution was used in place of the solution B. Table 2 shows the results.

Comparative Example 1 First, 10 ml of methylene chloride was charged into a volumetric flask having a capacity of 25 ml, and 7.57 × 10 ⁻³ mol of aluminum chloride was further charged as a catalyst.
Subsequently, n-butanol 3.03 × 1 was gradually cooled while cooling the volumetric flask so that the temperature in the system became about 20 ° C.
0 ^-2 mol (molar ratio 4.0 / 1.0) is charged. After the reaction between aluminum chloride and n-butanol is completed, methylene chloride is further charged, and the total volume is adjusted to the mark of 25 ml. The procedure was carried out in the same manner as in Example 1, except that this solution was used instead of Solution A. Table 3 shows the results.
Shown in

Comparative Example 2 A stirring device and a thermometer were attached to a four-neck flask having a capacity of 500 ml. 219 ml of methylene chloride was charged into this reaction vessel, and styrene was charged to a concentration of 8.19% by weight using a dropping funnel while stirring the inside of the reaction system, and then cooled to 0 ° C. .27 × 10 ⁻³ mol are added. After the addition, a polymerization reaction was carried out for 30 minutes to obtain polystyrene. As a result of analyzing the obtained polystyrene using GC and GPC, the residual unsaturated monomer was 0%, and the molecular weight of the generated polystyrene was 2,000.

After a polymerization time of 30 minutes, the temperature of the reaction solution was raised to 5 to 10 ° C.
An additional 12 g was fed, followed by the dropwise addition of 106.2 g of bromine over about 30 minutes. After a stirring time of 30 minutes, water is added. The catalyst and hydrogen bromide are removed from the organic layer by extracting several times with water. The purified solution was dropped into 1 L of hot water and the solvent was removed to obtain a solid. Further, the solid purified product was separated by filtration and dried under vacuum at 110 ° C. for 5 hours. As shown in Table 3, powder having a bromine content of 67% 71.3.
g (90.0% yield). When 0.1 g of this powder was heat-treated at 280 ° C. for 25 minutes, APHA was 50
It was 0 or more. From thermogravimetric analysis (TGA), 3
The% weight loss start temperature was 200 ° C.

[0048]

[Table 1]

[0049]

[Table 2]

[0050]

[Table 3]

[0051]

The process of the present invention starts from a styrene and a halogenating agent, especially a bromine-based halogenating agent, and can be used in a single reaction solution in a high yield in a single reaction solution. This makes it possible to produce a polymerization product which is halogenated to have excellent heat stability.

Claims (5)

[Claims] An unsaturated monomer comprising 50 to 100% by weight of a styrene monomer and 0 to 50% by weight of a monomer capable of cationic polymerization with a styrene monomer is polymerized in the presence of a catalyst. The halogenated styrene polymer,
The catalyst is a polymerization catalyst comprising a Lewis acid represented by the following general formula (1) and a nucleophilic substance, and the unsaturated monomer 10
Styrene polymer 100 obtained by cationic polymerization in the presence of 0.001 to 10 parts by weight of the catalyst per 0 parts by weight
Lewis acid is used as a halogenation catalyst in an amount of 0.0
A method for producing a halogenated styrene polymer, wherein the halogenation is carried out using 01 to 20 parts by weight. Embedded image Wherein Me is a trivalent or tetravalent metal atom, X is a halogen atom, R is hydrogen, a linear or branched alkyl group having 1 to 6 carbon atoms and an aliphatic amine group, and a is 3 Also 4,
(Ax) / x is 0 to 999. ] 2. The process for producing a halogenated styrene polymer according to claim 1, wherein the Lewis acid of the polymerization catalyst and the halogenation catalyst is a chlorinated or brominated metal. 3. The halogenated styrene polymer according to claim 1, wherein the nucleophilic substance is at least one compound selected from the group consisting of aliphatic alcohols and aliphatic amines having 6 or less carbon atoms. Recipe. 4. The method according to claim 1, wherein the nucleophile is hexanol, branched isopropanol, t-butanol, n-butanol.
The method for producing a halogenated styrene polymer according to claim 3, which is at least one compound selected from the group consisting of n-propyl alcohol, ethanol, and methanol. 5. The monomer cationically copolymerizable with a styrene monomer is at least one monomer selected from the group consisting of isobutylene, vinyl toluene, vinyl ethyl benzene, and vinyl propyl benzene. Item 5. The process for producing a halogenated styrene polymer according to any one of Items 1 to 4.