JPH03212412A - Butadiene-vinyl aromatic compound copolymer - Google Patents

Abstract

PURPOSE:To provide the subject novel polymer having excellent impact resistance and not losing the luster of the vinyl aromatic polymer by preparing from butadiene and a vinyl aromatic compound in a specific ratio so as to give a specified structure. CONSTITUTION:The objective copolymer consists of a copolymer comprising (A) 3-97wt.% of butadiene component and (B) 97wt.% of a vinyl aromatic compound (generally styrene) wherein the ratio of cis 1,4-bonds in the butadiene component of the copolymer is >=80wt.%. The copolymer may be prepared e.g. by a method comprising polymerizing the component A in the presence of a polymerization catalyst consisting of a rare earth metal phosphate salt, an organic Al compound and a Lewis acid in an inactive solvent such as hexane, adding the component B to the polymerization product and subsequently continuing the polymerization reaction so that the content of the component B becomes >=3wt.% in the copolymer. The rare earth metal is preferably neodymium, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a novel butadiene-vinyl aromatic compound copolymer which is excellent as an impact resistance imparting agent for vinyl aromatic polymers.

(Prior Art) Vinyl aromatic polymers such as polystyrene are used in a wide variety of fields due to their excellent moldability, dimensional stability, electrical properties, etc. However, they have the disadvantage of being brittle and easily cracked. In order to compensate for this drawback, various methods have been adopted to introduce a soft polybutadiene component into a hard vinyl aromatic polymer. Although a butadiene block copolymer itself can be used as an impact-resistant thermoplastic resin, it is known that the impact resistance of polystyrene can be improved by melt-kneading it with hard polystyrene.

However, although these styrene-butadiene block copolymers have the ability to impart impact resistance, they have the problem of reducing the rigidity of vinyl aromatic polymers, and a higher level of impact resistance is required. has been done.

On the other hand, rubbery polymers such as polybutadiene have been conventionally used as impact resistance imparting agents for vinyl aromatic polymers by the following method. That is, a rubbery polymer such as butadiene is dissolved in a vinyl aromatic monomer, and subjected to bulk polymerization or bulk/suspension polymerization with stirring or in the presence of a shear, so that the rubbery polymer such as butadiene is dissolved in a vinyl aromatic monomer. By dispersing the polymer in particle form, vinyl aromatic resins with impact resistance (e.g. high impact polystyrene,
An example of this is the production of ABS resin (ABS resin, etc.).

The above-mentioned butadiene-based rubbery polymers include so-called low-sis polybutadiene rubber obtained by anionic polymerization using organolithium alone or organic lithium as a main component, styrene-butadiene copolymer rubber, or transitions of cobalt, nickel, titanium, etc. High-cis polybutadiene rubbers obtained by catalysts containing metal compounds as main components or rare earth metal compounds have been widely used.

However, although these rubbery polymers have the effect of significantly increasing the impact resistance of polystyrene resins, they have the drawback of deteriorating properties such as rigidity and gloss. For this reason, those skilled in the art have been looking forward to the emergence of high performance rubbery polymers that can provide higher impact resistance with smaller amounts. To achieve this purpose, for example, Japanese Patent Application Laid-Open No. 48-46691 and Japanese Patent Application Laid-Open No. 52-86444 each disclose a polybutadiene rubber with a high cis content of 90% or more of cis-1,4 bonds. A method for producing an impact-resistant polymer using polybutadiene rubber, using a rubber whose main component is polybutadiene rubber having 90% or more of cis-1.4 bonds, and dispersing the polybutadiene rubber. Impact-resistant polystyrene with excellent gloss and having a rubber particle size controlled to 0.5 to 2.5 μm has been proposed. The high-cis polybutane rubber used in the impact-resistant polymer disclosed in these publications has superior performance in imparting impact resistance (especially impact resistance at low temperatures) compared to low-cis polybutadiene rubber. There were advantages to being there. However, in order to dissolve the high-cis polybutadiene rubber described in these publications in a styrene monomer and obtain small-sized dispersed rubber particles by the above-mentioned bulk polymerization or bulk suspension polymerization, strong stirring or As a result, when the rubber content in the styrenic monomer solution increases, the system viscosity increases, making it difficult to industrially obtain dispersed rubber particles with small diameters, and it is difficult to obtain dispersed rubber particles with a high impact strength. However, there was a problem in that it was difficult to produce impact-resistant polystyrene that also had high gloss. In addition, in the conventional technology, cis 1,4 of the polybutadiene moiety
A styrene-butadiene copolymer with a bond of 80% or more has not been obtained. In other words, the content of cis 1,4 bonds in the polybutadiene rubber is 90% or more in the above-mentioned prior art, and the content of cis 1,4 bonds in the butadiene moiety of the styrene-butadiene copolymer is 90% or more. This is because a 1,4 bond h<80% by weight or more is provided for the first time by the present invention.

In addition, 40% of cis-1,4 bonds in the polybutadiene moiety
The front and rear styrene-butadiene copolymer rubbers can have various structures and are used as reinforcing agents for styrene resins.

That is, for example, in JP-A-61-143415,
As a rubber, a styrene-butadiene polymer containing at least one blocked styrene moiety having a number average molecular weight of i, 000 to 10,000 obtained by a lithium-based polymerization catalyst and having a total styrene content of 3 to 25% by weight is used. A high-impact polystyrene with excellent gloss has been proposed using coalescing. The styrene-butadiene copolymer rubber disclosed in this publication has the advantage that it is easy to control the dispersed rubber particles into small particles by the above-mentioned bulk polymerization or bulk suspension polymerization, so it is easy to obtain high-impact polystyrene with excellent gloss. However, since a lithium-based catalyst is used as the rubber polymerization catalyst, the proportion of cis 1.4 bonds in the polybutadiene component is around 40%, making it a low-cis type polybutadiene, which has good impact resistance. The problem was that the imparting performance (particularly impact resistance at low temperatures) was insufficient.

(Problems to be Solved by the Invention) The problem of the present invention is to overcome the drawbacks of the above-mentioned conventional methods, and to develop a new butadiene which has excellent performance in imparting impact resistance (particularly impact resistance at low temperatures) to vinyl aromatic polymers. - A vinyl aromatic compound copolymer is provided.

(Means for Solving the Problems) As a result of intensive studies to solve the above problems, the present inventors have determined that a copolymer consisting of butadiene and a vinyl aromatic compound having a specific composition and a specific microstructure can solve the above problems. They have found that this can be achieved effectively and have completed the present invention.

That is, the present invention provides a copolymer comprising 3 to 97% by weight of butadiene and 97 to 3% by weight of a vinyl aromatic compound.
The present invention provides a copolymer characterized in that the bonding ratio is 80% by weight or more.

When the proportion of cis-1,4 bonds in the polybutadiene component of the copolymer of the present invention is less than 80%, the impact resistance of the copolymer to vinyl aromatic polymers (especially at low temperatures) It is not preferred because the performance of imparting impact resistance is poor. And more preferably, the proportion of cis 1,4 bonds is 9
It is 0% or more.

Moreover, the weight average molecular weight of the copolymer of the present invention is 50,000 to 50,000.
A range of 500.000 is preferred.

Next, the above-mentioned vinyl aromatic compounds which are other components of the copolymer of the present invention include vinyl aromatic monomers such as styrene, α-methylstyrene, para-methylstyrene, monochlorostyrene, dichlorostyrene, etc. , dipromostyrene, tribromostyrene, and other nuclear-substituted vinyl aromatic monomers. These vinyl aromatic compounds may be used alone or as a mixture of two or more types, but they must have the same or similar structure as the vinyl aromatic polymer intended for imparting impact resistance. preferable. Styrene is generally used.

The content of the vinyl aromatic compound in the copolymer of the present invention is preferably 5% by weight or more.

When the above content is 5% by weight or more, the copolymer has excellent performance in imparting impact resistance to vinyl aromatic polymers, and in the presence of the copolymer, bulk polymerization and bulk suspension may occur. By turbidity polymerization, when polymerizing a vinyl aromatic compound, it becomes easy to control the dispersed particles of the copolymer to be small particles. In addition, if the content of the vinyl aromatic compound in the copolymer exceeds 40% by weight, the copolymer may be melt-mixed with the vinyl aromatic polymer to form a vinyl aromatic polymer. It is possible to impart impact resistance.

Furthermore, when the copolymer of the present invention contains a block of the vinyl aromatic compound polymer, the ability to impart severe impact resistance to the vinyl aromatic polymer becomes even more excellent. .

Furthermore, when the content of the block of the aromatic compound polymer in the copolymer is 5% by weight or more,
In addition to the impact resistance imparting performance described above, it becomes easier to reduce the size of the dispersed rubber particles in the bulk polymerization or bulk suspension polymerization step.

Furthermore, when the weight average molecular weight of the vinyl aromatic compound polymer in the polymer is 5,000 or more, the impact resistance imparting performance becomes even better, and the reduction of the dispersed rubber particles to a smaller particle size is further improved. It becomes easier.

The copolymer of the present invention described above can be obtained by polymerizing butadiene and a vinyl aromatic compound under specific conditions using a specific catalyst described below. The above specific catalyst is (a) a polymerization catalyst comprising at least one selected from rare earth metal carboxylates, alcoholades, phenolates, phosphates, and phosphites, an organoaluminum compound, and a Lewis acid.

(b) Polymerization catalysts consisting of rare earth metal halides, organoaluminum compounds and 111N oxides, etc. can be mentioned. Examples of rare earth metals in the above polymerization catalyst include cerium, lanthanum, praseodymium, neodymium, and gadolinium, and neodymium and praseodymium are particularly preferred for use in the copolymer of the present invention. Among the components of the polymerization catalyst in (a) above, rare earth metal carboxylates, alcoholades, phenolates, phosphates, and phosphites are each represented by the following general formula.

In the following general formula, ln represents a rare earth metal such as cerium, lanthanum, praseodymium, neodymium, or gadolinium.

1) Carboxylate of rare earth metal; However, R is a residue of an organic acid selected from any of the following i) to vii) 1) Straight chain or branched alkyl group having 1 to 17 carbon atoms i) Carbon Linear alkenyl group of number 17) phenyl group iv) benzyl group ■) triphenylmethyl group vl) tricyclohexylmethyl group v11) organic acid residue H3 of rosin acid represented by the following general formula (in the formula = 2 = The carbon-carbon bond in ``S'' indicates a saturated single bond or an unsaturated double bond.) 2) Alcolade of rare earth metal; Ln + 0R)s However, R is an alkyl group having 1 to 20 carbon atoms 3) Rare earth metal Phenolate, naphthrate, thiophenolate, thionaphthlate represented by the following formula 1) or 11) R3 or R4, R5, R6 is hydrogen or has 1 to 2 carbon atoms
0 hydrocarbon group. ) 4) Rare earth metal phosphates and phosphites are Ln
(Px)s However, Px: a residue of phosphoric acid or phosphorous acid represented by the following general formulas (I) and (II).

(J here.

k.

m represents an integer greater than or equal to 0, They may be the same or different.

Furthermore, R1 to R4 represent a hydrogen atom, a hydrocarbon group, an aromatic hydrocarbon group, an alkoxy group, or an alkylphenoxy group, and R and R and R3 and R4 are each the same group, and may also be different groups. ) The acid of the above general formula (I) represents a pentavalent organic phosphoric acid compound, and is generally named in the form of a parent structure of pentavalent phosphoric acid and its mono- or diester. Such preferred examples include dibutyl phosphate, dibenzyl phosphate, dihexyl phosphate, diheptyl phosphate, dioctyl phosphate, bis(2-ethylhexyl) phosphate, bis(1-methylheptyl) phosphate, dilauryl phosphate. , dioleyl phosphate, diphenyl phosphate, bis(p-nonylphenyl) phosphate, bis(polyethylene glycol-p-nonylphenyl) phosphate, (butyl) phosphate (2-ethylhexyl)
, (1-methylheptyl) phosphate (2-ethylhexyl), (2-ethylhexyl) phosphate (p-nonylphenyl), monobutyl 2-ethylhexylphosphonate, 2-
mono-2-ethylhexyl ethylhexylphosphonate,
Mono-2-ethylhexyl phenylphosphonate, mono-p-nonylphenyl 2-ethylhexylphosphonate, mono-2-ethylhexyl phosphonate, mono- phosphonate
1-Methylheptyl, mono-p-nonylphenyl phosphonate, dibutylphosphinic acid, bis(2-ethylhexyl)phosphinic acid, bis(1-methylheptyl)phosphinic acid, dilaurylphosphinic acid, dioleylphosphinic acid, diphenylphosphinic acid , bis(p-nonylphenyl)phosphinic acid, butyl(2-ethylhexyl)phosphinic acid, (2-ethylhexyl)(1-methylheptyl)phosphinic acid, (2-ethylhexyl)(p-nonylphenyl)phosphinic acid, Butylphosphinic acid, 2
-Ethylhexylphosphinic acid, 1-methylhebutylphosphinic acid, oleylphosphinic acid, laurylphosphinic acid, phenylphosphinic acid, p-nonylphenylphosphinic acid, and the like.

Further, as a preferable example of the trivalent organic phosphoric acid compound represented by the above general formula (n), the parent structure of the pentavalent organic phosphoric acid compound exemplified in the above (I) is replaced with phosphorous acid, respectively. Examples of such compounds include:

Among the organic/organic phosphoric acid compounds exemplified above, preferred examples include bis(2-ethylhexyl) phosphate, bis(1-methylheptyl) phosphate, bis(p-nonylphenyl) phosphate, Bis(polyethylene glycol-
p-nonylphenyl), phosphoric acid (1-methylheptyl)
(2-ethylhexyl), (2-ethylhexyl) phosphate (p-nonylphenyl), mono-2-ethylhexyl 2-ethylhexylphosphonate, mono-p-nonylphenyl 2-ethylhexylphosphonate, bis(2-ethylhexyl), -ethylhexyl)phosphinic acid, bis(1-methylheptyl)
Examples include phosphinic acid, bis(p-nonylphenyl)phosphinic acid, (2-ethylhexyl)(1-methylheptyl)phosphinic acid, and (2-ethylhexyl)(p-nonylphenyl)phosphinic acid, and particularly preferred examples include phosphoric acid. bis(2-ethylhexyl) acid, bis(1-ethylhexyl) phosphate
-methylheptyl), mono-2-ethylhexyl 2-ethylhexylphosphonate, bis(2-ethylhexyl)
Examples include phosphinic acid.

Furthermore, among the components of the polymerization catalyst in (1), the rare earth metal halide is represented by the following general formula.

L　n　X　s However, X represents chlorine, bromine, or iodine.

Next, the organoaluminum compounds (a) and (b) above are represented by general formula (III).

AlH3-nHn... Group... 1 Group 1...
(m) (Here, n is 0, 1 or 2, R is a hydrocarbon group having 1 to 8 carbon atoms, and H is a hydrogen atom.) Preferred organoaluminum compounds include trimethylaluminum, triethylaluminum, Examples include triisopropylaluminium, triisobutylaluminum, trihexylaluminum, tricyclohexylaluminum, diethylaluminum hydride, diisobutylaluminum hydride, ethylaluminum dihydride, isobutylaluminum dihydride, and particularly preferred ones are triethylaluminum, triisobutylaluminum, diethylaluminium. hydride, diisobutylaluminum hydride. These may be a mixture of two or more types.

Next, the Lewis acid that is one component of the catalyst (a) is particularly a halogen element-containing Lewis acid compound.

These preferable ones include main group II of the periodic table [
Examples include halides or organometallic halides of elements belonging to a, IVa, or Va, and the halide is preferably chlorine or bromine. Examples of these compounds include methylaluminum dichloride, methylaluminum dichloride, ethylaluminum dibromide, ethylaluminum dichloride, butylaluminum dichloride, butylaluminum dichloride, dimethylaluminum bromide, dimethylaluminum chloride,
Diethylaluminium bromide, diethylaluminum chloride, dibutylaluminum bromide, dibutylaluminum chloride, methylaluminum sesquibromide, methylaluminum sesquichloride,
Ethylaluminum sesquibromide, ethylaluminum sesquichloride, dibutyltin dichloride, aluminum tribromide, antimony trichloride, antimony pentachloride, phosphorus trichloride, phosphorus pentachloride, and tin tetrachloride, and particularly preferred are diethylaluminum chloride and ethylaluminum chloride. Mention may be made of sesquichloride, ethylaluminum dichloride, diethylaluminum bromide, ethylaluminum sesquibromide and ethylaluminum dibromide.

Next, the organic N-oxide which is a component of the catalyst in (b) is the following cyclic or non-cyclic N-oxide.

(a) Cyclic N-oxide Nitrogen-containing heteroaromatic N-oxide: pyridine N-oxide, picoline N-oxide (α.

β, γ), 4-ethoxypyridine N-oxide, quinoline-N-oxide, isoquinoline-N-oxide, pyrimidine N-oxide, pyrazine N-oxide, pyridazine N-oxide, ethyl nicotinate N-oxide, collidine N- oxide, 3,4-lutidine N-oxide, phthalazine N-oxide, quinoxaline N-oxide, quinazoline N-oxide, 1-
Methylimidazole N-oxide, 1-methylbenzimidazole N-oxide, 1-methylpyrazole N
-oxide, benzoxazole N-oxide, benzothiazole N-oxide, 4-chloropyridine N-
oxide, tetrahydroquinoline N-oxide, etc.

Other cyclic N-oxides: N-methylpyrrolidine N
-oxide, N-butylpyrrolidine N-oxide,
N-methylpiperidine N-oxide, N-methylmorpholine N-oxide, 1-pyrorenine N-oxide, etc.

(b) Acyclic N-oxide trimethylamine N-oxide, triethylamine N
-oxide, trioctylamine N-oxide, N
, N-diethylaniline N-oxide, N,N-dimethylcyclohexylamine N-oxide, N,N-dimethylbenzylamine N-oxide, benzylideneaniline N-oxide, azoxybenzene, benzonitrile oxide, 2,4-dimethyl Benzonitrile oxide, 2.4.8-trimethylbenzonitrile oxide, 2-methoxy-1-naphthonitrile oxide,
2.6-dimethoxy-5-bromo-1-naphthonitrile oxide, etc.

Preferred organic N-oxides include nitrogen-containing heteroaromatic N-oxides.
- oxides, among them substituted pyridines such as pyridine, picoline, and penzologous derivatives of pyridine such as isoquinoline, quinoline, phenanthridine.
-Oxides are preferred.

The organic N-oxide used can be obtained as a commercial product or easily obtained by a reaction such as N-oxidation of a nitrogen-containing organic compound that is a precursor of the organic N-oxide.

The synthesis of such organic N-oxides is described in publications by Polymer et al. (e.g., J. Pharm. Soc. Japan
, 1947゜67, 33), Chemistry
of the Heterocyclic N-0x
ides (A, R, Katritzky and J.
, M., Logowski.

1971, Academic Press Inc.
) etc.

Preferred composition ratios of the three catalyst components (a) and (b) of the present invention include rare earth metal/aluminum/halogen element in the catalyst (a) (or nitrogen element in the catalyst (b)). ) is preferably 1/2 to 100/1 to 6,
Particularly preferred is a range of 115-5071.5-5.

The above-mentioned catalyst preferably used in the present invention has extremely high activity, and the amount of catalyst used is 1.5X10-3 expressed as rare earth metal per 100g of conjugated diene compound monomer to be polymerized.
It is preferably mol or less, and a particularly preferable range is 0.015X
10-3~1. OXl0-3 mol.

In addition, the above catalyst (a) is prepared by adding rare earth metal carboxylates, alcoholades, phenolates, phosphates, and phosphites in the presence or absence of butadiene, prior to the addition of a halogen element-containing Lewis acid, and organic aluminum. The activity can also be increased by pre-reacting with a compound.

This preliminary reaction is preferably carried out at a reaction temperature of 0 to 100°C. A particularly preferred reaction time is 0.05 to 3 hours.

Next, the method for obtaining the copolymer of the present invention using the above polymerization catalyst is as follows: i) polymerization of butadiene is allowed to proceed using the above catalyst in the presence of an inert solvent, and the polymerization of butadiene is substantially completed. After that, the above-mentioned vinyl aromatic compound is added, and the reaction is continued until the content of the vinyl aromatic compound in the polymer becomes 3% by weight or more. 11) In the absence or presence of an inert solvent. , the above catalyst is used to proceed with the polymerization of a mixture of butadiene and a vinyl aromatic compound, and the reaction is continued until the content of the vinyl aromatic compound in the resulting polymer becomes 3% by weight or more to form a butadiene-vinyl aromatic compound. There are methods for obtaining a solution of a vinyl aromatic compound (and an inert solvent) for a compound copolymer, and the copolymer of the present invention can be obtained by any of these methods. According to the method 1), a copolymer of butadiene and a vinyl aromatic compound with high blocking properties can be obtained. In the case of methods i) and if), the inert solvent is a solvent inert to the polymerization of the copolymer of the present invention, and preferred examples include butane, pentane, hexane, isopentane, heptane, octane, isooctane, etc. Aliphatic hydrocarbons, alicyclic hydrocarbons such as cyclopentane, methylcyclopentane, cyclohexane, methylcyclohexane, ethylcyclohexane, or benzene, toluene,
Aromatic hydrocarbons such as ethylbenzene and xylene, or mixtures thereof.

In the method i), the amount of the inert solvent is 300 parts by weight or more, more preferably 400 parts by weight, based on 100 parts by weight of butadiene. In the method ii), the amount of the inert solvent is 200 parts by weight or less, preferably 100 parts by weight or less, and more preferably 50 parts by weight or less, based on 100 parts by weight of the mixed monomers, and substantially the inert solvent is used. Embodiments without this are also possible.

Furthermore, in the method ii), the ratio of the mixed monomers of butadiene and vinyl aromatic compound is 1 to 70 parts by weight/99 to 99 parts by weight, respectively.
30 parts by weight, preferably 2 to 40 parts by weight/98 to 60 parts by weight, particularly preferably 3 to 30 parts by weight/97 to 70 parts by weight.

4 to 1, especially in embodiments that do not use inert solvents.
8 parts by weight/96 to 82 parts by weight or 5 to 15 parts by weight/
The amount is adjusted to 95 to 85 parts by weight.

In any of the above methods, since the polymerization rate of the vinyl aromatic compound is slower than that of butadiene, i
In the method (2), it is necessary to allow sufficient time for the subsequent polymerization of the vinyl aromatic compound to be carried out after the substantial completion of the polymerization of butadiene.

Also in method ii), polymerization of butadiene proceeds preferentially in the mixture of butadiene and vinyl aromatic compound, and as the amount of unreacted butadiene decreases, polymerization of vinyl aromatic compound progresses at a slow rate. It progresses and becomes incorporated into the polymer. Therefore, in this case as well, it is necessary to allow sufficient polymerization time.

Although it depends on the conditions such as the polymerization temperature and the amount of catalyst, in both of i) and ii), it is preferable to continue the polymerization for an additional 5 to 100 hours after the substantial polymerization of butadiene is completed. In addition, in the case of method ii), the blockiness of the copolymer increases when the polymerization is performed at a relatively low temperature.

In this case, the polymerization step of the butadiene component is carried out at low temperature,
It is also possible to shorten the polymerization time by carrying out the polymerization step of the vinyl aromatic compound at elevated temperatures. In the above, low temperature is in the range of 30 to 65℃, and high temperature is in the range of 65℃.
The temperature exceeds ℃.

The butadiene-vinyl aromatic compound copolymer thus obtained (or a solution of the vinyl aromatic compound of the copolymer) is mixed with a vinyl aromatic compound or a vinyl monomer copolymerizable therewith. A homogeneous solution is prepared, and a rubber-modified vinyl aromatic polymer is prepared by bulk suspension polymerization according to known methods.

(Examples) Specific embodiments of the present invention will be shown below in Examples, but these are intended to explain the gist of the present invention more specifically and are not intended to limit the present invention.

A butadiene-vinyl aromatic compound copolymer was obtained by the method described below. Subsequently, rubber-modified polystyrene and rubber-modified styrene-acrylonitrile copolymer were prepared using the copolymer, and their physical properties were measured. In addition, butadiene
Structural analysis of the vinyl aromatic compound copolymer, preparation of rubber-modified polystyrene, rubber-modified styrene-acrylonitrile copolymer, measurement of physical properties, etc. were carried out in accordance with the following methods and procedures.

1) Structural analysis of butadiene-vinyl aromatic compound copolymer 1) Conversion rate of butadiene and vinyl aromatic compound: After polymerization, a polymer solution containing a rubbery polymer obtained by the method described later was added to a polymer solution containing toluene. A predetermined amount of unreacted butadiene is collected in a sealed container, the weight of unreacted butadiene is determined using a gas chromatograph, and the conversion rate of butadiene is determined from the ratio to the charged butadiene. On the other hand, the solid weight is determined by devolatilizing a predetermined amount of the polymer solution at 230° C. for 30 minutes under high vacuum. The conversion rate of the vinyl aromatic compound is determined by the following formula.

Conversion rate of vinyl aromatic compound = (solid content weight - weight of charged butadiene x conversion rate of butadiene) Weight of charged vinyl aromatic compound i) Butadiene-vinyl aromatic compound copolymer and homovinyl aromatic compound copolymer from polymer solution Separation of the combined polymer The polymer solution is diluted with toluene, then poured into a mixed solvent of methyl ethyl ketone/acetone in a weight ratio of 45:55, and centrifuged. The supernatant and precipitate are each dried under 50'C1 vacuum. The weight of the polymer in the supernatant liquid is calculated, and the weight of the produced homovinyl aromatic compound polymer is determined. Further, the weight of the precipitate is extracted, and the weight of the produced butadiene-vinyl aromatic compound copolymer is determined.

111) Composition of butadiene-vinyl aromatic compound polymer: The weight ratio of butadiene and vinyl aromatic compound in the butadiene vinyl aromatic compound copolymer separated in 11) is determined by infrared spectrophotometry. The content of vinyl aromatic compounds is calculated from the absorption based on the benzene ring at 700 cm'. Then, by the Morello method, the cisl of the polybutadiene moiety was
, 4. Find the ratio of trans 1,4 and vinyl 1,2 bonds.

iv) Quantification of vinyl aromatic compound polymer block in butadiene-vinyl aromatic compound copolymer: 2 parts by weight of butadiene-vinyl aromatic compound copolymer was dissolved in 100 parts by weight of carbon tetrachloride, and di-tert-butyl Add 5 parts by weight of hydroperoxide, further add 0.01 part by weight of osmium tetraoxide, and heat to 100°C.
The double bonds present in the butadiene-vinyl aromatic compound copolymer are completely oxidized and decomposed by heating for 30 minutes. The precipitate produced by adding a large amount of methanol to the solution thus obtained is a block of the vinyl aromatic compound polymer. This precipitate is filtered, dried under vacuum, and then weighed to calculate the content (% by weight) of the vinyl aromatic compound polymer block in the butadiene-vinyl aromatic compound copolymer.

(2) Molecular weight of the butadiene-vinyl aromatic compound copolymer and the vinyl aromatic compound polymer block in the copolymer: The butadiene-vinyl aromatic compound polymer separated in 11) and iv) (or the commercially available polybutane The weight average molecular weight of the vinyl aromatic compound polymer block in the polystyrene rubber and the vinyl aromatic compound polymer block in the copolymer was determined by gel permeation chromatography according to a conventional method.

2) Preparation of rubber-modified polystyrene A butadiene-vinyl aromatic compound copolymer obtained by the method described later (or, as described later, obtained by polymerizing a mixture of butadiene and a vinyl aromatic compound.Butadiene-vinyl aromatic compound) Polymerization solution obtained as a solution of a vinyl aromatic compound of group compound copolymer) or commercially available polybutadiene dissolved in styrene and ethylbenzene (
or mixing) to prepare a polymerization stock solution consisting of 9.6 parts by weight of the rubbery polymer, 80.4 parts by weight of styrene, 10.0 parts by weight of ethylbenzene, and a chain transfer agent. This polymerization stock solution is continuously fed to a multistage polymerization machine equipped with a stirrer, and the temperature is raised to carry out continuous polymerization. The temperature inside the reactor is controlled so that the solid content concentration at the outlet of the first tank reactor is 38% by weight. Thus the first
In the tank reactor, phase inversion and particle formation of the rubbery polymer proceed. At the same time, the diameter of the dispersed rubber particles is adjusted by changing the stirring number of the first tank reactor. The solid content concentration at the outlet of the final tank reactor is 8
After polymerizing to 0% by weight, it is sent to a devolatilization device under heating and vacuum to remove unreacted styrene and ethylbenzene, and is granulated using an extruder to obtain rubber-modified polystyrene in the form of pellets.

3) Preparation of rubber-modified styrene-acrylonitrile copolymer In 2) above, the polymerization stock solution was mixed with 9.8 parts by weight of rubbery polymer, 48.9 parts by weight of styrene, and 16 parts by weight of acrylonitrile.
．． 3 parts by weight of ethylbenzene and 25.0 parts by weight of ethylbenzene, and then polymerization was started using an organic peroxide. Polymerization is carried out in the same manner except that the weight % is adjusted to obtain a rubber-modified styrene-acrylonitrile copolymer in the form of pellets.

4) Analysis and measurement of physical properties of rubber-modified polystyrene and rubber-modified styrene-acrylonitrile copolymer i) Content of rubber-like polymer in rubber-modified polystyrene and rubber-modified styrene-acrylonitrile copolymer; Preparation of 2) and 3) above Calculated from the rubbery polymer content in the liquid and the solid content concentration at the outlet of the final tank reactor.

11) Rubber particle diameter: Electron micrographs are taken using the ultra-thin section method, and the weight average particle diameter is determined for about 1000 rubber particles using the following formula.

(N is the number of particles having a diameter of D) 111) Izot impact strength: A test piece is prepared by injection molding, and the notched impact strength is determined in accordance with ASTM D256. The measured temperature is 23
℃, in two rows at -30℃.

iv) Flexural modulus: A test piece is prepared by injection molding and measured in accordance with ASTM D25B.

(2) Glossiness: The glossiness of the gate and end portions of the ASTM D638 dumbbell test piece is measured and the average value is determined.

Example 1 20. Inside purged with dry nitrogen. 2 kg of 1.3 butadiene and 8 kg of styrene were charged into a Q autoclave. Next, neodymium phosphate compound Nd(Pl)3 [however, Pl is 6 mmol, diisobutylaluminum hydride7
8 mmol was added and pre-reacted for 15 minutes at room temperature.

Furthermore, 6 ml of ethylaluminum sesquichloride was subsequently polymerized at 80°C for 26 hours, resulting in a polymer concentration of 24% by weight.
A viscous stock solution was obtained. The monomer conversion rate is 9 for butadiene.
9.5%, and styrene was 5%. The amount of homopolystyrene produced was 2% based on the weight of the produced rubber polymer.

Structural analysis of the rubbery polymer produced according to the above method revealed that it was a styrene-butadiene copolymer with a styrene content of 15.0% by weight and a blocked styrene content of 8.0% by weight. Furthermore, the bonding ratio of the butadiene moiety was 92.4 mol% for cis 1,4 bonds, 6.0 mol% for trans 1.4 bonds, and 1.6 mol% for vinyl 1,2 bonds. The weight average particle diameter of the rubbery polymer is 1
70,000 (this is referred to as rubbery polymer A).

A portion of the thus obtained styrene solution of rubbery polymer A was collected, and ethylbenzene (and acrylonitrile)
and rubber-modified polystyrene A-
1, A-2 and rubber modified styrene-acrylonitrile copolymers A-4, A-5 were obtained. Note that the stirring speed of the first tank reactor was 100 and 20 rpm. On the other hand, a styrene-butadiene copolymer was collected from the remaining styrene solution of the above-mentioned rubbery polymer A according to the method described above, and rubber-modified polystyrene A-3 and rubber-modified styrene-acrylonitrile copolymer A were collected according to the method described above. -6 was obtained.

Next, the physical properties of these rubber-modified polymers were measured. The results are shown in Table-1.

Example 2 A 20.Q autoclave whose interior was purged with dry nitrogen was charged with 2 kg of 1,3 butadiene and 8 kg of styrene. Into another container that had been purged with nitrogen in advance, 310 mmol of neodymium phosphate compound Nd(Pl) as catalyst components, 20 g of butadiene, and 130 mmol of diisobutylaluminum hydride were charged.
After pre-reaction for 15 minutes at room temperature, 10 mmol of ethylaluminum sesquichloride was added. After aging at 30°C for 3 hours, this catalyst component was added to the autoclave containing the monomer and polymerized at 60°C for 20 hours. The monomer conversion rate was 100% for butadiene and 3% for styrene. After the polymerization was completed, the same treatment as in Example 1 was carried out, and rubber-like polymer B was separated and collected. The structure of rubbery polymer B is shown in Table-1. Next, rubber-modified polystyrenes B-1 and B-2 were obtained using rubbery polymer B under the same conditions as those used to obtain A-1 and A-2 in Example 1. The physical properties are shown in Table-1.

Example 3 A 2ON autoclave whose inside was purged with dry nitrogen was charged with 2Kg of 1,3-butadiene and 8Kg of hexane. The same catalyst components as in Example 2 were added and polymerization was initiated at 60'C. After 4 hours (at this point the conversion rate of butadiene was 100%), 'j was added to styrene 8 and 8
The temperature was lowered to 0°C, and polymerization was continued for an additional 16 hours.

After polymerization, the same treatment as in Example 1 was carried out to obtain a rubbery polymer C. The structure of Rubber-like Polymer C is shown in Table 1, and it was a complete block SBR with a styrene content of 8.0%.

Then, using rubbery polymer C, A-
Rubber-modified polystyrene C-1, C-2 was obtained under the same conditions as those used to obtain 1, A-2. The physical properties are shown in Table-1.

Comparative Example 1 Ni-Ball 12, a commercially available high-cis polybutadiene rubber
In Example 1, A-1, A-
Rubber-modified polystyrene D-1°D-2 and rubber-modified styrene-acrylonitrile copolymers D-3 and D-4 were obtained in the same manner as in obtaining No. 2, A-4, and A-5. Analysis values of rubbery polymer and D-1, D-2, D-3, D-4
The physical property values are shown in Table-1.

Comparative example 2 1.3 butadiene 115 parts, cyclohexane 100 parts
n-butyllithium was added to a solution consisting of 0 parts by weight of o, os
Add o parts by weight, raise the temperature of the polymerization solution, and polymerize for 3 hours to obtain 1.3
After the entire amount of butadiene had been polymerized, 10 parts by weight of styrene was added and the polymerization was further carried out for 3 hours to obtain a rubbery polymer E consisting of a butadiene polymer block and a styrene polymer block. The structure is shown in Table-1. Next, in Example 1, A-1, A-2, A-4, A-
Rubber-modified polystyrene E-1 was obtained in the same manner as in obtaining 5.
E-2 and a rubber-modified styrene-acrylonitrile copolymer were obtained. The physical property values are shown in Table-1.

Comparative Example 3 Rubber-like polymer F was obtained in the same manner as in Example 1, except that the polymerization time was changed to 60° C. for 2 hours as the conditions for obtaining the rubber-like polymer. The structure of Rubbery Polymer F is shown in Table 1, and compared to Rubbery Polymer A of Example 1, it had significantly lower styrene joints and block styrene content. Next, rubber-modified polystyrenes F-1 and F-2 were obtained using rubbery polymer F in the same manner as in Example 1 for obtaining A-1 and A-2. The physical properties are shown in Table-1.

As shown in the comparative examples above, the conventional high-cis polybutadiene rubber (comparative example 1) has good impact resistance imparting performance, but it is difficult to make particles small, so the final rubber obtained Modified vinyl aromatic polymers have low gloss.

On the other hand, when the conventional styrene-butadiene copolymer rubber (Comparative Example 2) is used as an impact resistance imparting agent for vinyl aromatic polymers, it is easy to make small particles, so it is possible to use a rubber-modified vinyl aromatic rubber with good gloss. Although a group-based polymer is obtained, since the polybutadiene portion is low-cis polybutadiene, the impact resistance (especially low-temperature impact resistance) is low.

In addition, the rubbery polymer obtained by polymerizing butadiene in the presence of styrene by a known method (Comparative Example 3) has a low styrene content in the rubbery polymer, so it is different from conventional high-cis polybutadiene. Nothing has changed.

〔Effect of the invention〕

As is clear from the above explanation, the butadiene-vinyl aromatic compound copolymer of the present invention in which the butadiene moiety is high-cis polybutadiene has a vinyl aromatic compound copolymer compared to the conventional one (comparative example) shown above. Impact resistance properties of polymers (
The effect is that it is possible to provide a rubber-modified vinyl aromatic polymer with excellent balance between impact strength and gloss because it has excellent low-temperature impact resistance) and is dispersed as small particles in the vinyl aromatic polymer matrix. have.

(Margin below)

Claims (1)

[Claims] 1. Butadiene 3-91% by weight, vinyl aromatic compound 9
A copolymer comprising 7 to 3% by weight, wherein the proportion of cis-1,4 bonds in the polybutadiene component in the copolymer is 80% by weight or more.