JPH10237128A - Vinylaromatic polymer and production thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a vinylaromatic polymer, having a high yielding efficiency of a branched polymer and capable of effectively increasing the molecular weight of the vinylaromatic polymer. SOLUTION: This vinylaromatic polymer is produced by polymerizing its monomer by simultaneously using dicinnamoyl peroxide expressed by the formula and a polymerization initiator having 10hr half life in benzene at a temperature of 65-130 deg.C as polymerization initiators. The obtained vinylaromatic polymer has 1.1-3 range of a ratio (MwL/MwR) of a weight average molecular weight measured by GPC using a light scattering photometric detector (MwL) to a weight averaged molecular weight measured by GPC using a differential refractive index detector (MwR).

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 vinyl aromatic polymer which has a high efficiency of producing a branched polymer and which can effectively increase the molecular weight of the vinyl aromatic polymer obtained. It is about. The present invention also relates to a vinyl aromatic polymer having a high impact resistance and an improved fluidity by lowering the melt viscosity.

[0002]

2. Description of the Related Art Generally, vinyl aromatic polymers such as polystyrene are inexpensive and have excellent mechanical properties, and are therefore used in a wide range of fields. However, in recent years, demands for various performances as molding materials have been improved, and high performances have been demanded. For example, the molecular weight is increased in order to improve impact resistance and heat resistance, but on the other hand, increasing the molecular weight increases the viscosity at the time of melting, which causes a problem that the molding cycle is slowed down. It was difficult to balance.

It is generally known that a branched polymer is effective as a method for satisfying these conflicting performances. For example, Japanese Patent Publication No. 41-19511 discloses 2,2-bis (4,4-bis-t) as a polymerization initiator.
-Butylperoxycyclohexyl) propane is disclosed. Further, Japanese Unexamined Patent Publication No.
Japanese Patent Application Publication No. JP-A-2003-115139 discloses a styrene-based polymer having a branched structure obtained by using a polyfunctional polymerization initiator and a polyfunctional vinyl compound, and a method for producing the same.

Meanwhile, Journal of Chemical Society (J. Chem. Soc.), 1952, 24
On page 08, there is disclosed a method of using dicinnamoyl peroxide as a polymerization initiator in the polymerization of styrene.

[0005]

However, in the method disclosed in Japanese Patent Publication No. 41-19511, since the efficiency of forming a branched polymer is low, the performance of increasing the molecular weight and decreasing the melt viscosity is not obtained. There was a problem that it was not enough. Further, the method disclosed in Japanese Patent Application Laid-Open No. 8-59721 has a problem that a crosslinked product is easily formed.

[0006] Further, J.I. Chem. Soc. 1952
In the method of using dicinnamoyl peroxide disclosed on page 2408, the polymerization initiation efficiency is lower than that of benzoyl peroxide, which is generally widely used as a polymerization initiator for styrene, and a high molecular weight product cannot be obtained. was there.

The present invention has been made by paying attention to the problems existing in the prior art as described above. An object of the present invention is to provide a method for producing a vinyl aromatic polymer in which the efficiency of producing a branched polymer is high and the molecular weight of the obtained vinyl aromatic polymer can be effectively increased. It is in. Another object of the present invention is to provide a vinyl aromatic polymer having a high impact resistance and a low melt viscosity to improve the fluidity.

[0008]

Means for Solving the Problems To achieve the above object, a method for producing a vinyl aromatic polymer according to the first invention comprises the steps of: starting polymerization of a vinyl aromatic monomer with a polymerization initiator. A method for producing a vinyl aromatic polymer to obtain a vinyl aromatic polymer, comprising: as the polymerization initiator, dicinnamoyl peroxide and a temperature having a half-life in benzene of 10 hours (hereinafter, 10-hour half-life) Temperature)
And another polymerization initiator having a temperature of 65 to 130 ° C.

The method for producing a vinyl aromatic polymer according to a second aspect of the present invention is a method of starting polymerization of a vinyl aromatic monomer with a polymerization initiator, polymerizing at a predetermined polymerization temperature, and Wherein the polymerization temperature is set to 120 to 180 ° C. using dicinnamoyl peroxide as the polymerization initiator.

[0010] In a third aspect of the invention, a method for producing a vinyl aromatic polymer is a method in which polymerization of a vinyl aromatic monomer is initiated with a polymerization initiator, and polymerization is carried out at a predetermined polymerization temperature. A method for producing a vinyl aromatic polymer, wherein dicinnamoyl peroxide is used as the polymerization initiator at a polymerization temperature of 60 to 120 ° C and a polymerization conversion of 10
To 70-70% and then in the presence of another polymerization initiator with a half-life of 10 hours in benzene and a temperature of 65-130 ° C or by heat polymerization without using a polymerization initiator. It polymerizes at a polymerization temperature higher than the above-mentioned polymerization temperature at 180 ° C.

In a fourth aspect of the present invention, there is provided the method for producing a vinyl aromatic polymer according to any one of the first to third aspects, wherein the amount of the dicinnamoyl peroxide is 100% by weight of the vinyl aromatic monomer. 0.001 to 0.2 parts by weight per part by weight.

In a fifth aspect of the present invention, in the method for producing a vinyl aromatic polymer according to any one of the first to fourth aspects, the polymerization is a continuous polymerization method. A method for producing a vinyl aromatic polymer according to a sixth invention is the method according to any one of the first to fifth inventions, wherein the polymerization is performed in the presence of a rubber.

The vinyl aromatic polymer of the seventh invention is a vinyl aromatic polymer obtained by the method for producing a vinyl aromatic polymer of any of the first to sixth inventions,
The ratio of the apparent weight average molecular weight (MwR) calculated from the hydrodynamic volume of the molecule in the solvent of the polymer based on the standard polystyrene to the absolute weight average molecular weight (MwL) of the polymer (MwL / MwR) is 1.1 to 3.

[0014]

Embodiments of the present invention will be described below in detail. By using dicinnamoyl peroxide as a polymerization initiator, a vinyl aromatic polymer containing a vinyl group derived from dicinnamoyl peroxide at a terminal is first produced, and further, a vinyl group at the polymer terminal and a vinyl aromatic polymer are produced. By copolymerizing with a group-based monomer, a branched polymer is efficiently produced.

When a vinyl group at the terminal of the polymer and a vinyl aromatic monomer are copolymerized, 10
A peroxide or azo compound having a time half-life temperature of 65 to 130 ° C. is used in combination, or self-polymerization is started by heating without using other polymerization initiators, and a high molecular weight branched polymer is more efficiently produced. Can be manufactured. As a result, a vinyl aromatic polymer having a good balance of impact resistance, heat resistance and fluidity can be obtained.

Accordingly, in the method for producing a vinyl aromatic polymer, dicinnamoyl peroxide is not used alone as a polymerization initiator for initiating polymerization of the vinyl aromatic monomer, or a specific 10-hour half-life temperature is reduced. It is an essential condition to use in combination with other polymerization initiators.

The dicinnamoyl peroxide is a diacyl peroxide of cinnamic acid, and is a compound used as a polymerization initiator having a structure represented by the following formula (1).

[0018]

Embedded image

This dicinnamoyl peroxide is produced by reacting a chloroform solution of cinnamoyl chloride (cinnamate chloride) with caustic soda and hydrogen peroxide at 0 ° C. This manufacturing method is described, for example, in Journal of Chemical Society (J. Chem.
Soc. ), 1956, p. 427.

In the first invention, as a polymerization initiation method, dicinnamoyl peroxide is used in combination with another polymerization initiator having a 10-hour half-life temperature of 65 to 130 ° C., preferably 70 to 110 ° C. And a branched polymer can be efficiently produced. That is, in the relatively early stage of polymerization, the 10-hour half-life temperature is low (about 65 ° C.).
Efficient formation of a branched polymer by starting polymerization mainly with dicinnamoyl peroxide, generating a polymer having a vinyl bond at the end, and then initiating polymerization mainly with other polymerization initiators used in combination. Obtainable.

Therefore, the other polymerization initiators used in combination preferably have the above-mentioned range in which the half-life temperature of 10 hours is appropriately higher than that of dicinnamoyl peroxide. In the case of a polymerization initiator having a 10-hour half-life temperature of less than 65 ° C., a large amount of polymerization occurs with a polymerization initiator other than dicinnamoyl peroxide in the initial stage of polymerization, so that the efficiency of forming a branched polymer decreases. Further, a polymerization initiator having a 10-hour half-life temperature exceeding 130 ° C. is not preferable because the polymerization rate is reduced.

Other polymerization initiators used in combination include:
For example, diacyl peroxides such as benzoyl peroxide and toluyl peroxide, t-butylperoxyacetate, t-butylperoxy-2-ethylhexanoate, t-butylperoxybenzoate, di-t-
Butylperoxyisophthalate, di-t-butyl-cyclohexane-1,4-diperoxycarboxylate, t-butylperoxylaurate, t-butylperoxyisopropyl monocarbonate, t-butylperoxy-2-ethylhexyl monocarbonate, t-butyl Hexylperoxyacetate, t-hexylperoxy-2-ethylhexanoate, t-hexylperoxybenzoate, t-hexylperoxyisopropyl monocarbonate, 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate, etc. 1,1-bis-t-butylperoxy-
3,3,5-trimethylcyclohexane, 1,1-bis-t-butylperoxycyclohexane, 2,2-bis-t-butylperoxybutane, n-butyl-4,4-
Peroxyketals such as bis (t-butylperoxy) valerate and 2,2-bis (4,4-bis-t-butylperoxycyclohexyl) propane; di-t-butyl peroxide; t-butylcumyl peroxide;
And dialkyl peroxides such as 5-di-t-butylperoxy-2,5-dimethylhexane and dicumyl peroxide.

In the second invention, a self-initiated polymerization of dicinnamoyl peroxide and a vinyl monomer by heating is employed as a polymerization initiation method. That is, by setting the polymerization temperature to 120 to 180 ° C, preferably 130 to 170 ° C, more preferably 140 to 160 ° C,
A branched polymer can be produced efficiently. In the above-mentioned specific polymerization temperature range, dicinnamoyl peroxide is decomposed in a very short time, polymerization is started by the generated radical, and a polymer having a vinyl bond at a terminal is produced.

Further, since self-initiated polymerization of the vinyl monomer frequently occurs due to heating, the polymerization proceeds, thereby producing a branched polymer. On the other hand, when the temperature is lower than 120 ° C., the self-initiated polymerization of the vinyl monomer by heating is reduced, and
When the temperature exceeds 80 ° C., chain transfer to the vinyl aromatic monomer occurs frequently, and the production of a branched polymer is reduced, which is not suitable.

In the third invention, the polymerization temperature is from 60 to 120.
℃, preferably 70-110 ℃ polymerization conversion 10-70
%, Preferably 20 to 50%, of the vinyl aromatic monomer using dicinnamoyl peroxide. Next, the combined 10-hour half-life temperature is 65-1.
Heat polymerization at a polymerization temperature higher than the polymerization temperature at 70 to 180 ° C, preferably 80 to 170 ° C, more preferably 90 to 160 ° C in the presence of another polymerization initiator at 30 ° C or without using a polymerization initiator. By doing so, a branched polymer having a higher molecular weight can be produced more efficiently.

At this time, the other polymerization initiator used in combination may be added at the beginning of the polymerization or may be added during the polymerization. By selecting the polymerization initiator so that the decomposition temperature is different even when it is added at the early stage of polymerization, the polymerization of the vinyl aromatic monomer is started by disinnamoyl peroxide in the initial stage of the polymerization, and is used in the latter half of the polymerization. The polymerization is started by the other polymerization initiator.

In this case, if the initial polymerization temperature is lower than 60 ° C., the polymerization rate is low, and if it is higher than 120 ° C., the efficiency of increasing the molecular weight of the vinyl aromatic polymer decreases, which is not preferable. In addition, if the polymerization conversion rate is less than 10% or more than 70%, the efficiency of increasing the molecular weight of the vinyl aromatic polymer is undesirably reduced. Further, if the polymerization temperature in the latter half is lower than 70 ° C. or higher than 180 ° C., the efficiency of increasing the molecular weight of the vinyl aromatic polymer becomes undesirably low.

In the first to third aspects of the present invention, the amount of disinnamoyl peroxide used is determined based on the amount of the vinyl aromatic monomer 1
The amount is usually 0.001 to 0.2 part by weight, preferably 0.003 to 0.1 part by weight, more preferably 0.005 to 0.05 part by weight based on 00 parts by weight. If the amount of dicinnamoyl peroxide used is less than 0.001 part by weight,
The amount of the branched polymer produced tends to decrease. Also,
When the amount of dicinnamoyl peroxide exceeds 0.2 parts by weight, dicinnamoyl peroxide is present in a high concentration in the polymerization system, which is induced to decompose, lowering the polymerization initiation efficiency and producing a branched polymer. Tends to decrease.

When another polymerization initiator is used in combination, the amount of the polymerization initiator used is such that the desired polymerization conversion can be achieved when used in combination with disinnamoyl peroxide. Specifically, the used vinyl aromatic monomer 10
0 parts by weight, preferably 0.001 to 5 parts by weight,
More preferably, it is used in the range of 0.005 to 1 part by weight, particularly preferably 0.01 to 0.5 part by weight. If the amount of the polymerization initiator is less than 0.001 part by weight, there is no effect of using the polymerization initiator, and if it exceeds 5 parts by weight, the molecular weight of the obtained vinyl aromatic monomer decreases.

As the polymerization method, a bulk polymerization method, a solution polymerization method, a suspension polymerization method or a precipitation polymerization method is employed. Further, a combination of these polymerization methods is also employed. Industrially, a continuous polymerization method with good production efficiency of a vinyl aromatic polymer is advantageous. In this continuous polymerization method, one polymerization tank is used.
A method is adopted in which a polymerization apparatus having at least two groups, preferably two or more groups, is used, and the temperature of each polymerization tank is set to a predetermined temperature or a different temperature as necessary.

For example, a method in which polymerization is performed at a predetermined temperature and a predetermined residence time in one polymerization tank, or a predetermined temperature and a predetermined residence time which are respectively different in the first and second polymerization tanks,
After polymerization in the first polymerization tank, polymerization is performed in the second polymerization tank.

When two or more polymerization tanks are used, dicinnamoyl peroxide is added to the first polymerization tank as a polymerization initiator. Further, other polymerization initiators used in combination,
It may be added to the first polymerization tank or may be added to polymerization tanks after the second polymerization tank.

In the continuous polymerization method, the polymerization temperature is usually 70
To 180 ° C, preferably 80 to 170 ° C, more preferably 90 to 160 ° C. If the temperature is lower than 70 ° C., the polymerization rate is low. If the temperature exceeds 180 ° C., the chain transfer to the vinyl aromatic monomer frequently occurs, and the production of the branched polymer tends to decrease.

The vinyl aromatic monomer is at least one kind of vinyl aromatic monomer such as styrene, α-methylstyrene or p-methylstyrene, or is mainly composed of vinyl aromatic monomer. And a mixture of a copolymerizable vinyl monomer. Of these, styrene and α-methylstyrene are preferably used from the viewpoints of versatility and economical advantage that the applicable range is wide.

Examples of the vinyl monomer copolymerizable with the vinyl aromatic monomer include acrylic acid, methyl acrylate,
Acrylic monomers such as ethyl acrylate, propyl acrylate, butyl acrylate, octyl acrylate, lauryl acrylate, stearyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, methacrylic acid, methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl Methacrylate, octyl methacrylate,
Lauryl methacrylate, stearyl methacrylate,
Examples include methacrylic monomers such as 2-hydroxyethyl methacrylate and 2-hydroxypropyl methacrylate, fumaric acid esters, maleic acid esters, acrylonitrile, methacrylonitrile, phenylmaleimide, and cyclohexylmaleimide.

Of these, acrylonitrile or butyl acrylate is preferably used from the viewpoint of versatility and economy. Specific examples of the combination of the vinyl aromatic monomer and these vinyl monomers include styrene and acrylonitrile, styrene and α-methylstyrene, styrene and butyl acrylate, and α-methylstyrene and acrylonitrile.

Further, those vinyl aromatic monomers include polybutadiene rubber, block copolymer rubber of styrene and butadiene, SBR (styrene-butadiene copolymer rubber), NBR (acrylonitrile-butadiene copolymer rubber), EPR ( Ethylene-propylene copolymer rubber), E
A rubber such as PDM (ethylene-propylene-diene copolymer rubber) can also be dissolved. The content of these rubbers is desirably 2 to 40% by weight in the polymerization raw material. If the rubber content is less than 2% by weight, the impact resistance of the obtained vinyl aromatic polymer cannot be improved,
If it exceeds 40% by weight, the flexibility of the vinyl aromatic polymer tends to be too high.

In addition, in addition to the vinyl aromatic monomer and the polymerization initiator, if necessary, additives such as a chain transfer agent, an antioxidant, and an ultraviolet inhibitor, which are usually used for polymerization, are blended according to a conventional method. You can also.

By the above-mentioned production method, a desired vinyl aromatic polymer can be obtained. The vinyl aromatic polymer has an apparent weight average molecular weight (MwR) calculated from the hydrodynamic volume of a molecule in a solvent of the polymer based on standard polystyrene, and an absolute weight average molecular weight of the polymer. The ratio (MwL / MwR) to (MwL) is 1.
It is desirable to be in the range of 1-3. Specifically, the weight average molecular weight (Mw) of GPC measured by a differential refractometer detector
R) and the ratio (MwL / MwR) of the weight average molecular weight (MwL) of GPC measured by a light scattering photometer detector is in the range of 1.1 to 3, preferably 1.2 to 2.5. This ratio is 1.
If it is less than 1, the degree of branching is small, and it is difficult to achieve both the intended reduction in melt viscosity and improvement in mechanical properties such as impact resistance and heat resistance. Conversely, when this ratio exceeds 3, a crosslinked product tends to be easily formed.

The molecular weight measured by GPC using the above-mentioned differential refractometer detector is measured separately from the hydrodynamic volume of the molecule in the solvent of the polymer. Generally, a branched polymer tends to have a smaller molecular volume in a solution than a linear polymer. Therefore, branched polymers are underestimated by their actual molecular weight. On the other hand, the molecular weight measured by GPC using a light scattering photometer detector is an absolute molecular weight.

Therefore, the molecular weight of the branched polymer measured by both methods can be obtained as a large value as measured by a light scattering photometer detector. Accordingly, the weight average molecular weight (MwR) of GPC obtained by the differential refractometer detector and the weight average molecular weight (Mw) of GPC obtained by the light scattering photometer detector are obtained.
The vinyl aromatic polymer having a ratio (MwL / MwR) of L) exceeding 1 is a branched polymer, and it is considered that the larger the MwL / MwR, the more the branched structure.

According to the above embodiment, the following effects are exhibited. According to the method for producing a vinyl aromatic polymer of the embodiment, in particular, by using dicinnamoyl peroxide as a polymerization initiator, a vinyl aromatic polymer having a vinyl group derived from dicinnamoyl peroxide at a terminal is used. A coalescence is formed, and the vinyl group and the vinyl aromatic monomer are copolymerized. For this reason, the production efficiency of the branched vinyl aromatic polymer can be increased.

According to the method for producing a vinyl aromatic polymer of the embodiment, in particular, by using a polymerization initiator other than dicinnamoyl peroxide, the molecular weight of the obtained vinyl aromatic polymer can be effectively increased. Can be
Further, the impact resistance of the vinyl aromatic polymer can be increased thereby.

Further, according to the vinyl aromatic polymer of the embodiment, the melt viscosity can be reduced and the fluidity can be improved. According to the vinyl aromatic polymer of the embodiment, the moldability can be improved by lowering the melt viscosity and improving the fluidity.

In addition, according to the vinyl aromatic polymer of the embodiment, heat resistance can be improved.

[0046]

Next, the present invention will be described more specifically with reference to examples and comparative examples. The measurement of the ratio of the branched polymer of the obtained vinyl aromatic polymer and the physical properties such as the impact strength of the vinyl aromatic polymer were measured by the following methods.

Measurement of the ratio of the branched polymer: The ratio (MwL / MwR) of the weight average molecular weight MwL (absolute molecular weight) by GPC (gel permeation chromatography) -light scattering method and the apparent weight average molecular weight MwR by GPC-RI. It was measured. The higher the ratio, the more the branched polymer.

GPC: Gel permeation chromatograph (hlc-8020, built-in differential refractometer detector) manufactured by Tosoh Corporation, separation column (TSKgel-GM) manufactured by Tosoh Corporation
HXL x 3), company's light scattering photometer (LS-800)
0), the light source was 5 mW (He-Ne laser),
A temperature of 38 ° C., a solvent of THF (tetrahydrofuran),
The sample concentration was measured at 0.1% by weight.

Izod impact strength (notched): In accordance with ASTM D256. Melt flow rate (MFR, fluidity of molten polymer): based on ISO-R1133. (200 ° C, 5
(kg load) (Example 1, bulk polymerization of styrene) 100 parts by weight of styrene, 0.033 parts by weight of dicinnamoyl peroxide, t
-Butyl peroxyisopropyl carbonate 0.03
9 parts by weight were dissolved and the prepared polymerization stock solution was degassed.
5ml in glass ampoule with inner diameter 8mm and length 150mm
, Was sealed with a nitrogen purge, immersed in a thermostat, and polymerized at 120 ° C. for 10 hours. The polymerization conversion was 99%.

The GPC analysis of this polymer showed that the weight average molecular weight (MwL) was 78,000 by light scattering method, the number average molecular weight (MnL) was 2,970,000, and the apparent weight average molecular weight (MwR) by RI was 56,000. 20,000, number average molecular weight (Mn
R) was 205,000 and MwL / MwR was 1.40. In addition, the obtained polymer was dissolved in toluene, and poured into methanol to reprecipitate the polymer, followed by drying,
MFR was measured using a sample obtained by shredding a sheet compressed at 120 ° C. As a result, the MFR was 0.62 g / 1.
0 min. The Izod impact strength is 4.1k.
g · cm / cm. (Comparative Example 1, Bulk Polymerization of Styrene) A polymerization stock solution prepared by dissolving 100 parts by weight of styrene and 0.65 part by weight of dicinnamoyl peroxide was degassed, and 5 ml of a glass ampoule having an inner diameter of 8 mm and a length of 150 mm was added. The reactor was filled with nitrogen, sealed, sealed, immersed in a thermostat, and polymerized at 75 ° C. for 10 hours. As a result, the polymerization conversion was 60%. MwR was 442,000 and MnR was 78,000.

Comparative Example 1 shows that since the polymerization of styrene was carried out using dicinnamoyl peroxide alone and at a temperature at which self-initiated polymerization by heating was unlikely to occur, both the polymerization conversion and the molecular weight were lower than those in Example 1. Was done. This is J. Chem. Soc. As shown in p. 2408, 1952, it is considered that dicinnamoyl peroxide is susceptible to induced decomposition, resulting in low polymerization initiation efficiency. (Example 2, bulk polymerization of styrene)
The procedure was performed in the same manner as in Example 1 except that the amount of disinnamoyl peroxide used was changed to 0.0033 parts by weight. As a result, the polymerization conversion was 99%. Also, MwL4
31,000, MnL is 2270, MwR is 375,000,
MnR is 183,000 and MwL / MwR is 1.15
Met. Further, the MFR was 1.30 g / 10 min. The Izod impact strength is 2.3 kg · cm /
cm. (Comparative Example 2, Bulk Polymerization of Styrene) In Example 1,
The procedure was performed in the same manner as in Example 1 except that dicinnamoyl peroxide was not used. As a result, the polymerization conversion rate was 98%.
Met. Further, MwL was 417,000 and MnL was 22.0.
MwR is 39,000, MnR is 202,000,
MwL / MwR was 1.07. Further, the MFR was 0.75 g / 10 min. Further, the Izod impact strength was 2.2 kg · cm / cm. (Comparative Example 3, Bulk Polymerization of Styrene) In Comparative Example 2,
It carried out according to the comparative example 2 except having changed the polymerization temperature into 110 degreeC. As a result, the polymerization conversion was 95%. Further, MwL was 57,000, MnL was 262,000, MwR was 536,000, and MnR was 260,000. MwL / Mw
R was 1.08. Further, the MFR is 0.28 g /
It was 10 minutes. The Izod impact strength is 2.9.
kg · cm / cm. (Comparative Example 4, Bulk Polymerization of Styrene)
Comparative Example 2 was carried out except that the polymerization temperature was changed to 100 ° C. and the polymerization time was changed to 20 hours. As a result, the polymerization conversion was 93%. In addition, MwL74,000, M
nL is 34.5 million, MwR is 69.8 million, MnR is 3
It was 44,000 and MwL / MwR was 1.07.
Further, the MFR was 0.13 g / 10 min. The Izod impact strength was 3.6 kg · cm / cm. (Comparative Example 5, Bulk Polymerization of Styrene)
2,4-diphenyl-4-methyl-1 as a chain transfer agent
-It carried out according to the comparative example 2 except having added 0.09 g of pentene (MSD). As a result, the polymerization conversion rate was 98.
%Met. Further, MwL is 316,000 and MnL is 15.
60,000, MwR was 293,000, MnR was 136,000, and MwL / MwR was 1.08. Furthermore, MF
R was 2.06 g / 10 min. Also, Izod
The impact strength was 1.9 kg · cm / cm. (Example 3, bulk polymerization of styrene)
The procedure was performed in the same manner as in Example 1 except that 0.09 g of MSD was added. As a result, the polymerization conversion was 96%.
In addition, MwL is 445,000, MnL is 175,000, MwR
Is 323,000, MnR is 125,000, and MwL / M
wR was 1.38. Further, the MFR is 2.27 g.
/ 10 min. The Izod impact strength is 2.
It was 4 kg · cm / cm. Example 4 Bulk Temperature-Induced Polymerization of Styrene In Example 1, without using t-butylperoxyisopropyl carbonate, polymerization was carried out for 10 hours while the polymerization temperature was raised at a constant rate to 70 to 140 ° C. The program was heated for 3 hours at a temperature. Other than that, it carried out according to Example 1. As a result, the polymerization conversion rate was 98.
%Met. Further, MwL is 52.9 thousand, and MnL is 22.000.
The molecular weight was 0,000, the MwR was 38,000, the MnR was 152,000, and the MwL / MwR was 1.38. Furthermore, MF
R was 1.27 g / 10 min. Also, Izod
The impact strength was 2.7 kg · cm / cm.

FIG. 1 shows the relationship between MwL and MFR obtained by the above Examples and Comparative Examples. The styrene polymer obtained by the method using dicinnamoyl peroxide as a polymerization initiator (Examples 1 to 4) is different from the styrene polymer obtained without using dicinnamoyl peroxide (Comparative Examples 2 to 5). By comparison, all are MwL / Mw
The ratio of R was large, indicating that it had a branched structure. Also, as shown in FIG. 1, from the relationship between MwL and MFR, when the MwL was the same, the obtained styrene polymers had higher MFR in Examples 1 to 4 than Comparative Examples 2 to 5, It was found that the moldability was good and the moldability was excellent. Example 5 Continuous Polymerization of Styrene 86 parts by weight of styrene, 0.04 parts by weight of dicinnamoyl peroxide and 14 parts by weight of ethylbenzene were dissolved and the prepared polymerization stock solution was degassed. The mixture was continuously supplied to a 1-liter continuous reaction vessel equipped with a stirrer with a stirrer while keeping the polymerization temperature at 130 ° C. so that the average residence time was 5 hours, and the mixture was polymerized. After the polymerization, the polymerization solution was degassed under reduced pressure at 230 ° C. and 10 mmHg, and granulated (pelletized) with an extruder.

As a result, the polymerization conversion determined from the quantitative determination of the amount of residual styrene was 68%. GPC analysis of the polymer showed that MwL was 36,900, MnL was 1950,000, Mw
R is 300,000, MnR is 142,000, and MwL /
MwR was 1.23. The MFR is 2.86 g.
/ 10 min. Further, the Izod impact strength was 2.4 kg · cm / cm. (Example 6, continuous polymerization of styrene)
Disinnamoyl peroxide 0.01 as a polymerization initiator
Parts by weight and t-butylperoxybenzoate in an amount of 0.03
The procedure was carried out in the same manner as in Example 5 except that parts by weight were used in combination. As a result, the polymerization conversion was 78%. M of this polymer
wL is 463,000, MnL is 210,000, MwR is 3
43,000, MnR is 171,000, and MwL / MwR
Was 1.35. The MFR of this polymer is 3.
It was 33 g / 10 min. Further, the Izod impact strength was 2.5 kg · cm / cm. (Example 7, continuous polymerization of styrene)
The procedure was performed in the same manner as in Example 5, except that the amount of disinnamoyl peroxide used was changed to 0.5 part by weight. As a result, the polymerization conversion was 72%, MwL was 312,000, and MnL was 1
53,000, MwR was 271,000, MnR was 138,000, and MwL / MwR was 1.15. Also, MF
R was 1.44 g / 10 min. In addition, Izo
d Impact strength was 1.9 kg · cm / cm. (Comparative Example 6, Continuous Polymerization of Styrene)
Example 5 was carried out in the same manner as in Example 5, except that 0.04 parts by weight of 2,2-bis (4,4-bis-t-butylperoxycyclohexyl) propane was used instead of dicinnamoyl peroxide. As a result, the polymerization conversion was 79%. MwL is 376,000, MnL is 1590, M
wR is 3190, MnR is 142,000, and MwL
/ MwR was 1.18. The MFR is 1.33
g / 10 min. Further, the Izod impact strength was 2.1 kg · cm / cm. (Comparative Example 7, continuous polymerization of styrene)
Example 5 was carried out in the same manner as in Example 5, except that 0.04 parts by weight of t-butylperoxybenzoate was used instead of dicinnamoyl peroxide. As a result, the polymerization conversion rate was 77
%Met. MwL of this polymer is 366,000, MnL
Was 19.7, MwR was 333,000, MnR was 183,000, and MwL / MwR was 1.08. Also, M
FR was 1.47 g / 10 min. Furthermore, Iz
The od impact strength was 2.1 kg · cm / cm. (Example 8, continuous polymerization of rubber-containing polystyrene) 80 parts by weight of styrene, 6 parts by weight of high cis polybutadiene rubber (Nippol 1220SL, manufactured by Zeon Corporation)
A polymerization stock solution prepared by dissolving 0.01 part by weight of disinnamoyl peroxide, 0.03 part by weight of t-butylperoxybenzoate, and 14 parts by weight of ethylbenzene was degassed. The resulting mixture was continuously supplied to a 1-liter continuous reaction vessel equipped with a stirrer with a stirrer so that the average residence time was 5 hours while maintaining the polymerization temperature at 130 ° C., to carry out polymerization. After the polymerization, the polymerization liquid was devolatilized under reduced pressure at 230 ° C. and 10 mmHg, and pelletized with an extruder.

As a result, the polymerization conversion was 74%.
The MwL and MnL of this polymer were 28.4 and 14.3, respectively.
10,000, MwR is 211,000, MnR is 101,000,
MwL / MwR was 1.41. Further, the MFR was 4.35 g / 10 min. Further, the Izod impact strength was 16.6 kg · cm / cm. (Comparative Example 8, Continuous Polymerization of Rubber-Containing Polystyrene) The procedure of Example 8 was repeated, except that dicinnamoyl peroxide was not used. As a result, the polymerization conversion was 72%. The MwL of this polymer is 19.4
10,000, MnL is 101,000, MwR is 188,000, MnR
Was 96,000, and MwL / MwR was 1.08. The MFR of this polymer is 2.00 g / 10 mi.
n. Furthermore, Izod impact strength is 13.4 kg
Cm / cm. (Example 9, continuous temperature-increasing polymerization of styrene) In Example 6, an apparatus in which two continuous reaction vessels each having a 1-liter capacity and having a stirrer were connected to each other and the polymerization temperature of the first one was set to 80 ° C. While keeping the polymerization temperature of 135 ° C., polymerization was carried out by continuously supplying each of the reactors so that the average residence time was 3 hours. Other than that, it carried out according to Example 6.
As a result, the polymerization conversion was 80%. MwL of this polymer is 49.0 million, MnL is 233,000, and MwR is 3
55,000, MnR is 170,000, and MwL / MwR
Was 1.40. (Example 10, bulk heating polymerization of styrene / acrylonitrile) Using the same apparatus as in Example 4, 50 parts by weight of styrene, 50 parts by weight of acronitrile, 0.02 parts by weight of disinnamoyl peroxide, and t-hexylperoxyisopropyl Using 0.02 parts by weight of monocarbonate and 0.2 parts by weight of n-octyl mercaptan, polymerization was carried out for 10 hours while heating at a constant rate to 70 to 130 ° C.

When the polymerization temperature reached 100 ° C. for 5 hours, the container was opened, and the polymerization conversion was determined from the amount of residual styrene. The polymerization conversion was 58%. Further, the final polymerization conversion rate was 95%. Further, the polymer M
wL is 3390, MnL is 172,000, MwR is 2
69,000, MnR is 136,000, and MwL / MwR
Was 1.26. (Comparative Example 9, bulk heating polymerization of styrene / acrylonitrile) The procedure of Example 10 was repeated, except that no dicinnamoyl peroxide was used. As a result, the final polymerization conversion was 91%. Further, MwL of the polymer was 330,000, MnL was 165,000, and MwR
Is 314,000, MnR is 158,000, and MwL / M
wR was 1.05. (Example 11, bulk heating polymerization of α-methylstyrene / acrylonitrile) Using the same apparatus as in Example 4, 70 parts by weight of α-methylstyrene, 30 parts by weight of acronitrile,
While using 0.03 part by weight of disinnamoyl peroxide and 0.1 part by weight of t-butyl ruperoxy-2-ethylhexanoate, the temperature was raised to 70 to 120 ° C. at a constant rate while increasing the temperature by 1%.
Polymerization was carried out for 0 hour.

The polymerization time was 6 hours, and when the polymerization temperature reached 100 ° C., the container was opened and the polymerization conversion was determined. As a result, the polymerization conversion was 36%. Further, the final polymerization conversion rate was 83%. Further, the MwL of the polymer is 281,000, and the MnL is MnL.
Is 1490, MwR is 213,000, and MnR is 11.3.
MwL / MwR was 1.32. (Example 12, suspension polymerization of styrene) Capacity 1000 ml
Ion-exchanged water in a stainless steel autoclave
ml, 8 g of tricalcium phosphate and 0.1 g of sodium dodecylbenzenesulfonate were added. Then, styrene 20
0 g, discinnamoyl peroxide 0.05 g, benzoyl peroxide 0.1 g, and t-butyl peroxybenzoate 0.1 g were added. Then, the space in the autoclave was sufficiently replaced with nitrogen gas and sealed. Next, the temperature was continuously raised to 70 ° C. to 130 ° C. while stirring, and polymerized for 10 hours.

Then, a polymerization time of 5 hours and a polymerization temperature of 100
As a result of sampling at the time when the temperature reached ° C and determining the polymerization conversion, it was 65%. After polymerization, the mixture was cooled, filtered, washed with hydrochloric acid, washed with water, and dried to obtain 197 g of a polymer. The polymerization conversion was 99.9%. The polymer MwL was 436,000, MnL was 210,000, and MwR was 3
35,000, MnR is 16,000, and MwL / MwR
Was 1.30. (Example 13, continuous polymerization of styrene) A polymerization stock solution dissolved in a ratio of 86 parts by weight of styrene, 0.01 parts by weight of dicinnamoyl peroxide and 14 parts by weight of ethylbenzene was degassed, and two units were connected in series. In a continuous reaction tank with a stirrer having a volume of 1 liter, the polymerization temperature was maintained at 100 ° C. in the first stage and 130 ° C. in the second stage so that the average residence time was 1 hour in the first stage and 4 hours in the second stage. And polymerized.
Further, t-butyl peroxybenzoate was added dropwise to the second-stage reaction tank at a ratio of 0.03 parts by weight based on 100 parts by weight of the polymerization liquid.

After the polymerization, the polymerization solution was heated at 230 ° C. and 10 mmHg.
, And granulated by an extruder. The polymerization conversion obtained from the quantification of the residual styrene content was 55% in the first stage and 7 in the second stage.
5%. As a result of GPC analysis of this polymer, MwL
Is 48,000, MnL is 225,000, and MwR is 35.2.
MnR is 181,000 and MwL / MwR is 1.0.
36. The MFR is 3.40 g / 10 min.
Met. Further, the Izod impact strength is 2.5 kg · c
m / cm.

The technical ideas grasped from the above embodiment will be described below. 4. The vinyl aromatic polymer according to claim 1, wherein the amount of the other polymerization initiator used is 0.001 to 5 parts by weight based on 100 parts by weight of the vinyl aromatic monomer. 5. Manufacturing method.

In this case, the polymerization conversion of the vinyl aromatic monomer can be increased, and the molecular weight of the obtained vinyl aromatic polymer can be increased. The method according to claim 5, comprising a plurality of polymerization tanks, wherein dicinnamoyl peroxide is supplied to the first polymerization tank, and another polymerization initiator is supplied to the first polymerization tank or the second polymerization tank or later. A method for producing the vinyl aromatic polymer according to the above.

In this case, the branched polymer can be continuously produced with high yield. The apparent weight average molecular weight (MwR) is the weight average molecular weight of a gel permeation chromatograph (GPC) using a differential thermal refractometer detector, and the absolute weight average molecular weight (MwL) is detected by a light scattering photometer. The vinyl aromatic polymer according to claim 7, which is a weight average molecular weight measured by a gel permeation chromatograph (GPC) using a vessel.

With this configuration, it is possible to effectively reduce the melt viscosity of the vinyl aromatic polymer, improve the mechanical properties, and suppress the formation of a crosslinked product.

[0063]

As described above, according to the present invention, the following effects can be obtained. According to the method for producing a vinyl aromatic polymer of the first invention, the production efficiency of the branched polymer can be increased, and the molecular weight of the obtained vinyl aromatic polymer can be effectively increased. . In addition, the impact resistance of the vinyl aromatic polymer and the fluidity at the time of melting can be exhibited in a well-balanced manner.

According to the method for producing a vinyl aromatic polymer of the second invention, dicinnamoyl peroxide is used as a polymerization initiator, and no other polymerization initiator is used.
The production efficiency of the branched polymer can be increased, and the molecular weight of the obtained vinyl aromatic polymer can be increased. Further, the impact resistance of the vinyl aromatic polymer and the fluidity during melting can be exhibited in a well-balanced manner.

According to the method for producing a vinyl aromatic polymer of the third invention, the same effect as in the first invention or the second invention can be exhibited more efficiently by two-stage polymerization. .

According to the method for producing a vinyl aromatic polymer of the fourth invention, the effect of any one of the first to third inventions can be obtained by setting the amount of disinnamoyl peroxide used in a predetermined range. It can be surely demonstrated.

According to the method for producing a vinyl aromatic polymer of the fifth invention, in addition to the effects of any one of the first to fourth inventions, the production efficiency for obtaining the vinyl aromatic polymer is increased. And a large amount of a vinyl aromatic polymer can be easily and quickly obtained.

According to the method for producing a vinyl aromatic polymer of the sixth invention, in addition to the effects of any of the first to fifth inventions, the impact resistance of the obtained vinyl aromatic polymer is further improved. Can be improved.

As described above, according to the method for producing a vinyl aromatic polymer of the present invention, a branched vinyl aromatic polymer having an excellent balance between impact strength and fluidity can be efficiently obtained. Therefore, the industrial use value is large.

The vinyl aromatic polymer according to the seventh aspect of the present invention is a branched polymer having a large molecular weight, resulting in high impact strength, improved fluidity due to a decrease in melt viscosity, and improved moldability. Excellent in nature.

[Brief description of the drawings]

FIG. 1 is a graph showing a relationship between a weight average molecular weight and a melt flow rate.

 ────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Daisuke Kayaba 8 West Gate, Taketoyo-cho, Chita-gun, Aichi

Claims (7)

[Claims] 1. A method for producing a vinyl aromatic polymer in which a vinyl aromatic monomer is polymerized by a polymerization initiator to obtain a vinyl aromatic polymer, wherein the polymerization initiator is dicinna A method for producing a vinyl aromatic polymer using moyl peroxide and another polymerization initiator having a half-life in benzene of 10 hours and a temperature of 65 to 130 ° C. 2. A method for producing a vinyl aromatic polymer, in which polymerization of a vinyl aromatic monomer is initiated by a polymerization initiator, polymerization is carried out at a predetermined polymerization temperature, and a vinyl aromatic polymer is obtained. A method for producing a vinyl aromatic polymer, wherein disinnamoyl peroxide is used as the polymerization initiator and the polymerization temperature is set to a temperature of 120 to 180 ° C. 3. A method for producing a vinyl aromatic polymer, in which polymerization of a vinyl aromatic monomer is initiated by a polymerization initiator, polymerization is carried out at a predetermined polymerization temperature, and a vinyl aromatic polymer is obtained. Using dicinnamoyl peroxide as the polymerization initiator, a polymerization conversion rate of 10 to 7 at a polymerization temperature of 60 to 120 ° C.
Polymerized to a range of 0% and then in the presence of another polymerization initiator having a half-life of 10 hours in benzene and a temperature of 65 to 130 ° C., or by heat polymerization without using a polymerization initiator, and A method for producing a vinyl aromatic polymer which is polymerized at a polymerization temperature higher than the polymerization temperature at 180 ° C. 4. The amount of said dicinnamoyl peroxide is 0.1 to 100 parts by weight of a vinyl aromatic monomer.
The method for producing a vinyl aromatic polymer according to any one of claims 1 to 3, wherein the amount is from 001 to 0.2 parts by weight. 5. The method for producing a vinyl aromatic polymer according to claim 1, wherein the polymerization is performed by a continuous polymerization method. 6. The method according to claim 1, wherein the polymerization is performed in the presence of a rubber.
A method for producing a vinyl aromatic polymer according to any one of claims 1 to 5. 7. A vinyl aromatic polymer obtained by the method for producing a vinyl aromatic polymer according to any one of claims 1 to 6, wherein standard polystyrene is used as a standard, and The ratio (MwL / Mw) of the apparent weight average molecular weight (MwR) calculated from the hydrodynamic volume of a molecule to the absolute weight average molecular weight (MwL) of the polymer
R) is a vinyl aromatic polymer having 1.1 to 3;