KR100380012B1 - Method for preparing syndiotactic polystyrene having impact-resistance and compatibility - Google Patents

Abstract

The present invention relates to a method for producing syndiotactic polystyrene having impact resistance and compatibility, and more particularly, to a method for producing syndiotactic polystyrene using macro monomers as a raw material.

The present invention for this purpose a) a macromonomer having a styrene group as an end group; And b) copolymerizing styrene under a metallocene catalyst to provide a method for preparing syndiotactic polystyrene having impact resistance and compatibility.

Syndiotactic polystyrene resin obtained by the production method according to the present invention is excellent in heat resistance, impact resistance, and compatibility, it is easy to control the molecular weight and molecular weight distribution of the branch chain containing can be effectively used as a material of various molded products have.

Description

Method for producing syndiotactic polystyrene having impact resistance and compatibility {METHOD FOR PREPARING SYNDIOTACTIC POLYSTYRENE HAVING IMPACT-RESISTANCE AND COMPATIBILITY}

[Industrial use]

The present invention relates to a method for producing syndiotactic polystyrene having impact resistance and compatibility, and more particularly, to a method for producing syndiotactic polystyrene using macro monomers as a raw material.

[Prior art]

Polystyrene is a colorless transparent thermoplastic resin. Synthesis of styrene monomer using bulk polymerization, suspension polymerization, etc. is a representative thermoplastic resin with excellent electrical properties with low dielectric constant and excellent thermal fluidity and colorability. Through the use of various daily necessities.

In particular, the polymerization of the styrene monomer using a metallocene catalyst can produce syndiotactic polystyrene having high stereoregularity. The preparation of syndiotactic polystyrene is reported in Macromolecules, 1986, 19 , 2464. Macromolecules 1988, 21 , 3356.

Syndiotactic polystyrene polymerized with metallocene has emerged as a new engineering plastic by exhibiting excellent heat resistance and chemical resistance due to high stereoregularity, along with advantages such as low dielectric constant and excellent thermal fluidity of conventional polystyrene.

Syndiotactic polystyrene has this advantage but is limited in use due to its low impact resistance.

In order to improve the impact resistance, there is a method of mixing a rubbery elastomer with a styrene polymer (Japanese Patent Laid-Open No. 62-257950, Japanese Patent Application No. 1-146944, Japanese Patent Application Publication No. 1-279944, etc.). However, in this case, in order to increase the dispersibility, it is necessary to knead sufficiently, and since the rubbery elastic body has elasticity, it is necessary to cut the rubbery elastic body finely, but there is a problem in handling because of its elasticity. In addition, there is a problem in that cross-linking of the rubber or molecular weight decrease of the resin during mixing kneading.

In order to solve this problem, a method of metallocene polymerization of a styrene monomer in the presence of a rubbery elastomer has been proposed (Korean Patent Publication No. 95-12726). However, the chemical bond between the rubbery elastomer and the styrene polymer is small, which greatly increases impact resistance. I couldn't.

In order to overcome the above problems, the method of grafting a rubbery elastomer to polystyrene is most effective. However, since general polystyrene is very well dissolved in aromatic solvents, the grafting reaction can be easily induced by using a solution polymerization method. However, syndiotactic polystyrene is hardly dissolved in a general purpose solvent, so that a homogeneous reaction is difficult. It is not possible and there are many constraints on the grafting reaction.

On the other hand, although recently reported on the modification of syndiotactic polystyrene using a macro monomer having a styrene end group (K. endo, Polymer, 40, 5977-5980, 1999) at -78 ℃ for the preparation of macro monomers It is difficult to industrialize, such as the need to react, and the use of halogen compounds.

SUMMARY OF THE INVENTION The present invention has been made in view of the problems of the prior art, and an object thereof is to provide a method for producing syndiotactic polystyrene having impact resistance and compatibility.

Another object of the present invention is to provide a method for producing syndiotactic polystyrene having impact resistance and compatibility for polymerization using macromonomers.

[Means for solving the problem]

The present invention to achieve the above object,

a) Macro monomer which has a styrene group represented by following formula (1) as an end group

[Formula 1]

Where

M is an olefin monomer having a conjugated double bond,

n is an integer of at least 5; And

b) styrene

Copolymerization Under Metallocene Catalyst

It provides a method for producing syndiotactic polystyrene having impact resistance and compatibility comprising a.

The macro monomer having a styrene group as the end group is preferably a monomer prepared by ion polymerizing diisopropylamide lithium with an ion polymerization initiator.

Hereinafter, the present invention will be described in detail.

[Action]

According to the present invention, the syndiotactic polystyrene prepared by copolymerization of macro monomers and styrene has an effect such as graft polymerization by elasticity of macro monomers to exhibit impact resistance. However, since macromonomers having normal vinyl groups at their ends are difficult to show high stereoregularity during polymerization by metallocene polymerization with styrene, syndiotactic polystyrene is prepared by maintaining the form of terminal groups as styrene groups. It is.

In addition, general syndiotactic polystyrene is not compatible with other polymers. Syndiotactic polystyrene prepared by the method of the present invention is compatible with other polymers because the syndiotactic polystyrene may be compatible with monomer properties of branched chains of macro monomers. This is excellent.

In addition, the present invention can be adjusted in advance the molecular weight and molecular weight distribution of the branch chain included in the macro monomer because the macro monomer used is prepared by ion polymerization. Therefore, it is easy to control the molecular weight and molecular weight distribution of the branched chain including the syndiotactic polystyrene of the present invention produced using such macro monomers. In fact, in general graft polymerization, it is very difficult to control the molecular weight and molecular weight distribution of the branched chain when the polymerized polystyrene includes branched chains.

As such, the macromonomer having a styrene group as an end group, which is excellent in impact resistance and compatibility of the present invention, and has a molecular weight and a molecular weight distribution of branched chains controlled in syndiotactic polystyrene, may be prepared by the following Scheme 1. have.

Scheme 1

Wherein M is an olefin monomer having a conjugated double bond,

Examples are butadiene, isoprene and the like, and n is an integer of 5 or more.

That is, the macro monomer having the styrene group as an end group

Iii) lithiating methylstyrene with diisopropylamide lithium; And

Ii) olefin having conjugated double bond with lithiated methylstyrene in step iii)

Ion Polymerization of Monomer

It may be prepared by a method comprising a.

The macromonomer was prepared by Y. Nagasaki, T. Tsuruta et al. (Macromole. Chem. Rapid. Commu. 10, 403 (1989)).

Hereinafter, the manufacturing process of syndiotactic polystyrene prepared using the macromonomer of the present invention will be described.

(Production of Macro Monomers Having a Styrene Group at the Terminal)

After dissolving p-methyl styrene monomer in THF in a closed reactor in a nitrogen atmosphere, lithium isopropylated with diisopropylamide. Thereafter, a monomer to be used as a branch chain, particularly butadiene, is added to lithiated methylstyrene to prepare a macromonomer having a styrene group at the terminal. The molecular weight is determined by the ratio of the monomer and lithium injected.

As for the macro monomer, nuclear magnetic resonance analysis can observe the vinyl monomer spectrum of styrene end groups at 5.2, 5.7 and 6.7 ppm and the macro monomer spectrum at 2.7 ppm.

The residual monomer content was only 40 to 90 ppm, and the observed styrene terminal vinyl characteristic spectra were attributed to the macro monomers.

In this case, butadiene, isoprene, etc. may be used as the monomer to be used as a branch chain.

(Production of Styrene Copolymer)

The macro monomer and the styrene monomer prepared above are placed in a closed reactor in a nitrogen atmosphere, and then dissolved in a solvent such as benzene, toluene, xylene, ethylbenzene, which have been removed from oxygen and water, or stirred without a solvent.

Aluminoxanes, especially alkyl aluminoxanes, are charged at 1 to 10 mol% relative to the styrene monomer. Aluminoxane may be added in excess to remove impurities in the reactor.

After the addition of the aluminoxane, the titanium catalyst is added at a ratio of 1/400 to 1/1000 to the aluminum atom of the aluminoxane.

After about 1 to 2 hours of catalyst addition, a mixed solution of alcohol and hydrochloric acid was added to terminate the reaction. The remaining catalyst was washed away with hydrochloric acid, and the resulting polymer was washed with alcohol and dried under reduced pressure.

The present invention will be described in more detail with reference to the following examples and comparative examples. However, an Example is for illustrating this invention and is not limited only to these.

EXAMPLE

Example 1

(Production of macromonomers having styrene groups as end groups)

200 ml of THF is added to a 500 ml high pressure reactor from which oxygen and water are removed, and stirred at 20 ° C. 20 ml of diisopropyl amide (2.80 ml) and 5 mmol (2.37 ml) of n-butyllithium cyclohexane solution are injected. . Butyllithium reacted with diisopropyl amide to form diisopropyl amide lithium, and the solution was pale yellow.

5 mmol (0.66 ml) of p-methylstyrene was slowly added dropwise to the reactor over 10 minutes, followed by reaction for about 3 hours to lithiate p-methylstyrene.

Butadiene 500 mmol (27.05 g) was added to the reactor by pressurizing with nitrogen, and the reaction was further performed for 4 hours.

After stopping the reaction with methanol, the solvent was evaporated under reduced pressure and dried in a vacuum oven for 24 hours to obtain a macromonomer having a styrene group as an end group.

(Production of Syndiotactic Polystyrene)

1.0 g of a macromonomer having a styrene group as a terminal group was dissolved in 15.01 ml (131 mmol) of styrene in a 250 ml reactor in which oxygen and water were removed, and stirred at room temperature, followed by 2.83 ml (6 mmol) of aluminoxane toluene solution. And 0.0075 mmol of pentamethylcyclopentadienetrimethoxy titanium. After increasing the stirring speed, the temperature of the reactor was raised to 60 ° C.

After 1 hour of titanium catalyst addition, the reaction was terminated with methanol / hydrochloric acid (weight ratio 10: 1) solution. The residual catalyst is washed away with hydrochloric acid and the resulting polymer is washed with alcohol and dried under reduced pressure.

Comparative Example 1

The preparation of syndiotactic polystyrene proceeds in the same manner as in the preparation of syndiotactic polystyrene of Example 1, except that only styrene is polymerized without macro monomers.

Comparative Example 2

10 g of finely divided butadiene rubber is placed in a 250 ml reactor from which oxygen and moisture are removed, and 15.01 ml (131 mmol) of styrene is added thereto, followed by stirring to dissolve. After the butadiene rubber is completely dissolved, 2.83 ml (6 mmol) of aluminoxane toluene solution and 0.0075 mmol of pentamethylcyclopentadiene trimethoxytitanium are added thereto. After increasing the stirring speed, the temperature of the reactor was raised to 60 ° C.

After 1 hour of titanium catalyst addition, the reaction was terminated with methanol / hydrochloric acid (weight ratio 10: 1) solution. The residual catalyst is washed away with hydrochloric acid and the resulting polymer is washed with alcohol and dried under reduced pressure.

Syndiotactic polystyrene resin obtained by the production method according to the present invention is excellent in heat resistance, impact resistance, and compatibility, it is easy to control the molecular weight and molecular weight distribution of the branch chain containing can be effectively used as a material of various molded products have.

Claims (5)

In the manufacturing method of syndiotactic polystyrene, a) Macro monomer which has a styrene group represented by following formula (1) as an end group [Formula 1] Where M is an olefin monomer having a conjugated double bond, n is an integer of at least 5; And b) styrene Copolymerization Under Metallocene Catalyst Method for producing syndiotactic polystyrene having impact resistance and compatibility comprising a. The method of claim 1, A method for producing syndiotactic polystyrene having impact resistance and compatibility, wherein the macro monomer of a) is a monomer prepared by ion polymerization of diisopropylamide lithium with an ion polymerization initiator. The method of claim 2, The macro monomer is Iii) lithiating methylstyrene with diisopropylamide lithium; And Ii) olefin having conjugated double bond with lithiated methylstyrene in step iii) Ion Polymerization of Monomer Method for producing a syndiotactic polystyrene having a shock resistance and compatibility that is a monomer prepared by a method comprising a. The method of claim 1, A method for producing syndiotactic polystyrene having impact resistance and compatibility, wherein M of the macromonomer of a) is butadiene or isoprene. The method of claim 1, The metallocene catalyst is pentamethylcyclopentadienetrimethoxytitanium.The method for producing syndiotactic polystyrene having impact resistance and compatibility.