JPS601247A - Styrene polymer composition - Google Patents

Abstract

PURPOSE:To provide a styrene polymer compsn. having well-balanced properties between resistance to impact and heat and moldability, by incorporating a small quantity of an ultra-high-molecular-weight styrene polymer in a styrene polymer having a viscosity within a specified range. CONSTITUTION:The titled styrene polymer compsn. has a viscosity (in 10wt% toluene soln.) of 30-60cps and contains 0.8-3wt% ultra-high-molecular-weight styrene polymer having an MW of 2,000,000 or above and not move than 10wt% low-molecular styrene polymer having an MW of 50,000 or below. The titled styrene polymer compsn. can be obtd. by producing an ultra-high-molecular-weigt styrene by an anion polymn. method or an emulsion polymn. method and blending it with a styrene polymer. Examples of the styrene polymers are those obtd. by polymerizing styrene, alpha-methylstyrene, vinyltoluene or vinylxylene alone or a mixture thereof.

Description

DETAILED DESCRIPTION OF THE INVENTION Styrene polymers have excellent transparency, moldability, and rigidity, and are therefore widely used as molding materials for household goods, electrical appliances, and the like.

Against the backdrop of the recent trend toward switching from high-grade resins due to the soaring prices of raw materials and energy saving during molding, simultaneous improvements in the impact strength, moldability, and heat resistance of styrene polymers have been strongly desired. ing.

Conventionally, impact resistance strength has been improved by lowering the average molecular weight of styrene polymers, but as the average molecular weight increases, moldability decreases, and one plasticizer such as mineral oil has been used to improve moldability. When added, the rigidity and heat resistance decrease, and moreover, adhesion caused by the plasticizer occurs near the mold exhaust hole, which is transferred as scratches to the product surface or adheres as dirt, resulting in molded products @b11M It has been extremely difficult to improve the quality of multiple items at the same time, such as reducing the quality by 70%. Methods of decreasing the ratio YA of low molecular weight portions are known, such as in Japanese Patent Publication No. 33-6986 and Japanese Patent Publication No. 57-30843, but as the ratio of low molecular weight portions increases, the impact strength decreases significantly. Methods have also been proposed to balance moldability and impact strength by adjusting molecular distribution, but this has not yet satisfied market demands for improvement.

As a result of intensive research by the present inventors to develop a styrene polymer with a well-balanced impact strength, moldability, and heat resistance,
By incorporating a very small amount of an ultra-high molecular weight styrene polymer into a styrene polymer, we have achieved the present invention, which significantly improves the impact resistance of the styrene polymer without affecting its moldability.

That is, the styrene polymer has a viscosity of 30 ape to 60 cps in a toluene solution based on 10% by weight at 25°C, and an ultra-molecular weight styrene polymer having a molecular weight of 2 million or more and 0.8% to 6.0% by weight. A styrene polymer composition characterized in that it contains a binder.

and 10% by weight of styrene polymer with a molecular weight of 50,000 or less.
The styrene polymer composition is characterized in that: Compared to conventional styrene polymers, the styrene polymer composition of the present invention has superior impact strength, moldability, and heat resistance, for example, with the same moldability. The gender balance has been significantly improved.

In the present invention, the viscosity of the toluene solution based on 10% by weight of the styrene summer coalescence is determined by considering the shape of the molded product, the purpose of use, etc.
It is set in the range of 0 cpθ to 60 cps. 10% by weight of styrene polymer) The viscosity of the toluene solution is 30 cp
If it is less than s, there is almost no improvement in impact strength even if an ultra-high molecular weight styrene polymer is contained. Also 60 cps
If it exceeds this value, the moldability is extremely poor (and impractical).

The content of ultra-high molecular weight styrene polymer with a molecular weight of 2 million or more is 0.8% by weight to 6.0% by weight. It is necessary to be within the range of U weight.

More preferably, it is in the range of 1.0 weight to 2.5 weight. If the viscosity exceeds 3.0, it is necessary to reduce the average molecular weight of the styrene polymer excluding the ultra-high molecular weight styrene polymer in order to obtain a styrene polymer having the viscosity of a toluene solution based on the set 10 weight ratio. As a result, the degree of improvement in impact resistance strength becomes smaller. Furthermore, the ultra-high molecular weight styrene polymer affects the fluidity, and the degree of improvement in moldability is also reduced. On the other hand, if the weight coefficient is less than 0.8, the effect of improving surface 1 impact strength by the ultra-high molecular weight styrene polymer will not be achieved. Styrene polymers with a molecular weight of 50,000 or less have a positive effect on moldability, but have the effect of significantly reducing impact strength. If it is 10% by weight or less, preferably 5% by weight or less, the balance between moldability and impact resistance strength will be improved, but if it exceeds 10% by weight, the improvement in impact resistance strength of the ultra-high molecular weight styrene polymer will be offset. Undesirable.

The narrower the molecular weight distribution of styrene polymers other than ultra-cylindrical molecular weight styrene polymers, the better for improving moldability and impact strength. Its molecular weight distribution is preferably 3.0 min.

In addition, in the present invention, the molecular weight of the ultra-high molecular weight styrene polymer is determined by the GP○ measurement method using APA (produced by Toyo Ichita Kogyo Co., Ltd.).
HLO-802A), the company's GPO column (TSK
-GIICL G 6 Q [] Q H6-TSK-
GEL' G5000H6). Also, 5
The molecular weight of the styrene polymer, which is less than 10,000, was measured using a GPO column (TSK-GELGMH6X, 2 columns) manufactured by the same company. Content is calculated by area ratio. The viscosity of the 10% (by weight) styrene polymer toluene solution is measured using an Ostwald Canon Fenske viscosity tube #350Y.

The styrene polymer of the present invention can be produced by bulk or solution polymerization at low temperature to produce an ultra-high molecular weight styrene polymer, or by using a polyfunctional low-temperature catalyst (3 to 6 (] functional). A method of producing an ultra-high molecular weight styrene polymer by anionic polymerization, emulsion polymerization, etc., and then combining it with known styrene 1 in a solution state or pellets together, etc. It is manufactured by a method of mixing in an appropriate ratio using a known mixing method 7, or the like.

The styrene polymer of the present invention is one obtained by polymerizing styrene, α-methylstyrene, vinyltoluene, p-methylstyrene, vinylxylene, vinylnaphthalene, etc. alone or in combination.

The styrene polymer of the present invention may contain additives such as stearic acid, behenic acid, zinc stearate, ethylene bisstearamide, and the like. In addition, as antioxidants, hindered phenols, hindered bisphenols, hindered trisphenols, etc., such as 2,6-di-t-butyl-4-methylphenol;
Stearyl-β-(ro,5-di-t-decyl-4-hydroxydiphenyl)propionate; Triethylene glycol-biaX-3-(3-t-butyl-4-hydroxy-5-methylphenyl)propionate, etc.; Phosphorus type compounds, for example) IJ (2,4-di-t-butylphenyl)
Phosphite T 4 + 4'-tetylidene-bis(3-methyl-6-t-butylphenyl-di-tridene) phosphite, etc. can be added.

Furthermore, depending on the shape and use of the molded article, 1liJ plasticizers such as mineral oil, polyethylene glycol, etc. may be added.

Hereinafter, the present invention will be explained in detail with reference to Examples.

In addition, the physical property test method of the example is described below.

Melt flow rate: Conforms to SO R1133.

Vicat softening point: According to ASTM D1525.

No notch, Izo impact strength: Conforms to ASTM D256 except that notch 2 is not placed in the test piece.

Cyclic impact strength: A square test piece with a thickness of 2 cm and 9 crn x 5 cm was created using the compression molding method (2DO'O)11.
Fix the part 2-5cm vertically from the center with metal fittings, and
A missile of R1160y was dropped from a height of 5 cr/L onto the center of the test piece, and the number of times until a crack appeared was counted.

One-shot impact strength: Compression molding method (200℃) thickness 2 mm
28. A disk-shaped test piece with a diameter of 10 cm was prepared, and an annular portion with a radius of 7 cm to 10 crrL was fixed with metal fittings.
? A copper ball is dropped into the center of the test piece, and 50% of the test piece is
The height that will be destroyed will be charged.

Examples-1, 2; Comparative Examples-1, 2, 3 When equipped with a stirring blade, 6 of the compositions shown in Table 1 were added to one reactor.
After replacing the air present in the reactor with nitrogen, polymerization was carried out at the temperature shown in Table 1 for 10 hours. Thereafter, the reaction solution is taken out and unreacted monomers are removed at 200° C. and under a reduced pressure of 15 mgHg to obtain a styrene polymer. Table 1 shows the viscosity of a 10% by weight toluene solution of the obtained styrene polymer at 25°C. The obtained styrene polymer was mixed in the proportions shown in Table-2. To obtain a homogeneous mixture 2,
After dissolving the mixed styrene polymer in toluene, methanol is added to precipitate the styrene polymer, and after drying,
Physical properties were measured. The physical property values are shown in Table-2.

The molecular weight distributions of the styrene polymers excluding the ultra-molecular weight styrene polymers of Examples 1 and 2 were 2.7 and 2.9, respectively.

(2) Styrene polymer tAl, (Bl, (C) uses 1,1-bis(t-gtylboxy)cyclohexane.

Styrene polymer (El is an organic polymer having the following structural formula) - [Margin "' Examples - 6, 4; Comparative Examples - 4, b, 6. 7. 8 Table -
Examples 1 and 2 other than '1- shown in 6; Comparatives 1 and 2,
A styrene polymer was obtained by carrying out two operations similar to those in Step 3. Table 6 shows the viscosity of a 10M diluted toluene solution of the obtained styrene polymer at 25°C.

The obtained styrene polymer 2 was mixed in the proportions shown in Table-4,
Examples 1 and 2: The same operations as in Comparisons 1, 2, and 3 were performed to measure the styrene vehicle coalescence loss and physical properties. Table of physical property values
4.

In addition, the molecular weight of the styrene polymers excluding the ultra-heavy molecular weight styrene polymers of Examples 3 and 4 is 2.5, 2.7, respectively.
Met.

]Artificial margin (Table 6) ■1,1-bis(t-butylperoxy) Schiff-xane 3-F2 From Table 2, 5 The polymer of the present invention has excellent moldability and impact strength. I understand that. When a plasticizer was used and the moldability was the same as that of the polymer of the present invention (Comparative Example 2), the heat resistance was significantly lowered. It can also be seen that when the low molecular weight styrene polymer (molecular weight 50,000 or less) is 10% or more (Comparative Example 6), the impact resistance strength decreases significantly. The same thing can be seen from Table-4.

That is, when the strength, heat resistance, and properties were the same as those of the polymer of the present invention (Comparative Example 7), the moldability deteriorated, and when the moldability was improved with a plasticizer (Comparative Example 8), the heat resistance There is a significant decrease in the strength, and the strength also decreases slightly. It can be seen that when the content if7 of the supersieve molecular weight styrene polymer was increased (Comparative Example-6) - no improvement in moldability or strength was observed.

The polymer of the present invention has simultaneously improved moldability, impact strength, and heat resistance.

Patent applicant: Asahi Kasei Industries, Ltd.

Claims (1)

[Claims] 1. The viscosity of a 10 ifjt% toluene solution at 25°C is 3D cpθ~60 cp day, and the styrene polymer has a molecular weight of 0.81% to 3.0 liters and has a molecular weight of 2 million or more. Styrene polymer composition 2 characterized in that it is styrene polymer composition 2, characterized in that the styrene polymer composition according to claim 1, characterized in that the styrene polymer having a molecular weight of 50,000 or less is 10 m1% or less