JPH0362813A - High impact strength styrene polymer composition having high strength and excellent appearance - Google Patents

Abstract

PURPOSE:To obtain the title composition which is useful as a substitution resin for ABS resin, because of its high strength, appearance, and markedly increased shock resistance. CONSTITUTION:The subject composition is obtained by mixing (A) dispersion particles of a rubber polymer and (B) a styrene polymer comprising structural units of (i) formula I ((l), (m), (n) are 1 to 20: R1 to R4 are H, 1 to 5C alkyl, cyclohexyl, phenyl wherein at least one among them is 2 to 5C alkyl) and (ii) formula II (R1 is H, methyl; R2 is H, 1 to 5C alkyl) or a mixture thereof with component (i) wherein the continuous phase comprises a continuous phase of 0.006 to 0.000006 i/ii molar ratio.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a rubber-modified styrenic polymer composition having excellent strength and appearance.

(Prior Art) Conventionally, rubber-modified styrenic polymer compositions with excellent impact strength have been widely used in household electrical appliances, audio equipment, and the like. Recently, its use as an alternative resin to ABS resin is expanding. Along with this, improvements in impact resistance,
There has been a strong demand for improvements in rigidity and appearance.

It is well known that impact strength can be improved by increasing the content of rubber forming the rubbery polymer or by increasing the particle size of the rubbery polymer. However, such a method results in a decrease in rigidity and appearance characteristics. especially,
Significant deterioration in appearance characteristics.

In order to improve the appearance characteristics, it is necessary to reduce the particle size of the rubbery polymer, but as the particle size becomes smaller, the impact strength decreases. In particular, when the particle size becomes 2.0 μm or less, the impact strength decreases significantly.

Other improvement methods include changing the properties of the rubber forming the rubbery polymer and optimizing the particle size distribution of the rubbery polymer.

However, methods such as changing the type or amount of rubber forming the rubbery polymer or changing the morphology of the rubbery polymer will not significantly improve the balance of impact resistance, appearance, and rigidity, which are mutually exclusive. It is possible.

(Problems to be Solved by the Invention) In view of the current situation, the present inventors did not improve the properties of the rubber that forms the rubbery polymer that forms the dispersed phase, and the form of the rubbery polymer. The inventors have discovered that the strength and appearance of a rubber-modified styrenic polymer composition can be improved by improving the styrenic polymer that forms the continuous phase, and have arrived at the present invention.

(Means for Solving the Problems) That is, the present invention provides a rubber-modified styrenic polymer composition containing a rubber-like polymer as dispersed particles, comprising: (a) dispersed particles made of a rubber-like polymer; and (b) )
General formula; % formula %) (In the formula, jL m, n are integers from 1 to 20, R+
, R2, R3, and R4 are hydrogen, an alkyl group having 1 to 5 carbon atoms, a cyclohexyl group, or a phenyl group, and at least one of them is an alkyl group having 2 to 5 carbon atoms. ), (wherein R1 is hydrogen or a methyl group, and R2 represents hydrogen or an alkyl group having 1 to 5 carbon atoms.

) or a mixture of this styrenic polymer and a styrenic polymer consisting of the structural unit (13) as a continuous phase, and the ratio of the structural units in this continuous phase, A /B(mo1/mo+
) is 0.006 to 0.000006, and the continuous phase is 7
The present invention provides a rubber-modified styrenic polymer composition having excellent strength and appearance and comprising a styrenic polymer continuous phase of 5 to 99% by weight.

Preferably, the amount of rubbery polymer of the invention is from 1 to 25% by weight. More preferably, it is 2 to 20% by weight. When the amount of the rubber-like polymer is less than 1% by weight, the strength-reinforcing effect of the rubber-like polymer is not exhibited, and impact resistance strength is not achieved. If it exceeds 25% by weight, the rigidity and appearance will be significantly reduced, which is undesirable from a practical standpoint.

The rubber forming the rubbery polymer used in the composition of the present invention has a glass transition temperature (Tg) of 30°C or lower, such as polybutadiene, styrene-butadiene random copolymer, styrene-butadiene. Block copolymer, ethylene-propylene copolymer, ethylene-propylene-nonconjugated diene terpolymer, isoprene polymer,
One or more types of styrene-isoprene copolymer, silicone rubber, etc. are used. Further, the molecular weight and degree of branching of the rubbery polymer are not limited.

Although the particle size of the rubbery polymer of the present invention is not limited to a specific size, it is preferably in the range of 0.2 to 7.0 μm.

The continuous phase of the present invention ranges from 75 to 99 weight percent, which is 100 weight percent minus the amount of rubbery polymer.

The ratio of the constituent units of the styrenic polymer forming the continuous phase, (
A)/(B) (mo I/mo +) is 0°006
It is necessary to be in the range of ~0.000006. More preferably, it is in the range of 0.003 to 0.00003.

If the ratio (A)/(B) is less than 0.000006, the effects of the present invention will not be exhibited and the resin will not be equivalent to conventional rubber-modified styrene resins.

Moreover, when it exceeds 0.006, rigidity and heat resistance decrease, which is not preferable.

In the present invention, in order to introduce the structural unit (A), the general formula: % formula % (wherein E, m, n are integers of 1 to 20, R,
2, R3, and R4 are hydrogen, an alkyl group having 1 to 5 carbon atoms, a cyclohexyl group, or a phenyl group, and at least one of them is an alkyl group having 2 to 5 carbon atoms. ) 3 or more repeating units, preferably 5 to 30 repeating units
A styrenic monomer is polymerized using an initiator having

As such an initiator, for example, those having the following repeating units can be used.

C-(C1lz) 6-CIL (Cll□), -CO
:OII I II OC2H,0 To introduce the structural unit (B), general 2; (in the formula, R,
is hydrogen or a methyl group, R is hydrogen or has 1 carbon number
~5 alkyl group.

) is carried out by polymerizing vinyl monomers shown in the following.

Examples of such vinyl monomers include styrene,
α-methylstyrene, vinyltoluene, p-methylstyrene, etc. can be used. These vinyl monomers can be used alone, in mixtures, or in combination with small amounts of other olefinic monomers within a range that does not impede the effects of the present invention.

The molecular weight and molecular weight distribution of the styrene polymer forming the continuous phase are not particularly determined.

The amount of the rubbery polymer referred to in the present invention is determined by infrared absorption spectrum, thermal decomposition chromatogram, etc.

In addition, the average particle diameter of the dispersed particles of the rubber-like polymer can be determined by taking a transmission electron micrograph (magnification: 10,000 times) using the cross section method of a styrene-based polymer string material. The number of reserved particles was measured from 800 to 2000, and the average particle diameter was calculated from -Σn1-Di/Σni. Since the dispersed particles shown in the electron micrograph are not perfectly circular, the longitudinal diameter (a) and widthwise diameter (a) of the particles shown in Figure 1 are different.
b) and calculate the particle diameter (Di) using the following formula.

a+b Particle diameter (Di)=Also, the constituent unit ratio (A)/(B) is determined by the following method.

Dissolve 1 g of rubber-modified styrene monomer composition in 20 cc of methyl ethyl ketone, and use a centrifuge to
Separate the rubbery polymer at 0,000 rpm. The supernatant liquid is collected by decantation, and about 20 cc of methanol solution is added to precipitate the styrenic polymer. The styrene polymer thus obtained was heated at 200°C, 15mm H
Dry for 30 minutes under a vacuum of 30 g.

Using this styrene polymer, JASCO's JNM-
13G is measured using Gχ270.

Measurement was performed under the following measurement conditions.

Complete decamping, 45° pulse, observation frequency -67
, 8MHz.

Latency time - 2.5 seconds, number of scans = 100000 times,
Sample concentration -10% by weight, solvent = 1.1,2.2-tetrachloroethane (d2), sample tube -10+nm, measurement temperature -120°C1 The peak derived from the carbon of the methylene group of the long alkyl chain is 29 Appears at .4 ppm. In addition, the peak derived from the carbon adjacent to the quaternary (or tertiary) carbon number in the long chain is 33. Appears at 7 ppm.

By confirming the presence of this peak, it is possible to confirm the presence or absence of the structural unit (A) in the styrenic polymer.

The quantitative determination of the constituent unit ratio (A)/(B) is based on the constituent unit (B).
It is calculated from the peak area ratio of 29°4 ppm to the total area of the peak appearing at 38 to 50 pPm derived from methine and methylene groups.

A calibration curve for calculations is created using the standard samples below.

After dissolving the sample polymerized under the composition and polymerization conditions shown in Table 1 in 10 times the amount of methyl ethyl ketone, the same amount of methanol was slowly added to precipitate the polymer, and the polymer was precipitated at 200°C under a reduced pressure of 3 mmHg. Dry for 30 minutes.

Table-1 It has 7 repeating units.

As another measurement method, it is also possible to perform DSC analysis using DSC-41 manufactured by Shimadzu Corporation and obtain the Tg of the styrene polymer. Measurement is carried out using a sample treated similarly to the +3C NMR measurement at a heating rate of 18°C/min.

A calibration curve is created using the above-mentioned standard sample, and the constituent unit ratio (A)/(B) can be determined using this calibration curve.

The rubber-modified styrenic polymer (&11 product) of the present invention is:
It can be produced by a known method such as bulk polymerization, bulk-suspension polymerization, solution polymerization, etc. using the above-mentioned initiator. In addition to the above-mentioned initiators, it is also possible to use initiators commonly used in the production of rubber-modified styrenic polymers.

It is also possible to produce a styrenic polymer (composition) by separately producing a styrenic polymer containing structural unit (8) and a rubber-modified styrenic polymer and blending them.

Therefore, the rubber-modified styrenic polymer composition of the present invention is
The styrenic polymer consisting of the structural units (A) and (B) above alone, or this styrenic polymer and the structural units (
It is composed of a mixture with a styrenic polymer consisting of B).

The rubber-modified styrenic polymer composition of the present invention contains 12 to Furthermore, it is preferable to add an organic polysiloxane.

The organic polysiloxane can be added in an amount of 0.001 to 5.0 parts by weight per 100 parts by weight of the rubber-modified styrenic polymer composition. More preferably, it is 0.002 to 4.0 parts by weight. If it is less than 0.001 parts by weight, there will be no reinforcing effect such as impact strength, and if it exceeds 5.0 parts by weight, the rigidity and heat resistance will be significantly lowered, which is not preferable.

When adding organic polysiloxane, 0.01 to 2.0
It is preferable to add parts by weight of stearic acid and metal salts of behenic acid (zinc, calcium, magnesium) at the same time, as this greatly improves the impact strength. It is also preferable to add ethylene bisstearamide at the same time.

The rubber-modified styrenic polymer composition of the present invention includes additives,
For example, stearic acid, behenic acid, zinc stearate,
Calcium stearate, Magnesium stearate,
Ethylene bisstearamide, mineral oil, etc. can be added.

In addition, as antioxidants, hindered phenols, hindered bisphenols, hindered trisphenols, etc., such as 2.6-sheet t-butyl-4-methylphenol, stearyl β-(3,5-di-L -Bujirou 4
-hydroxyphenyl) propionate, triethylene glycol bis-3-(3-t-butyl-4-hydroxy-5-methylphenyl) propionate, and the like can be added.

Phosphorous compounds, such as tri(2,4-di-butylphenyl)phosphite, 4,4-butylidene-bis-(
3-Methyl-6-t-butylphenyl-di-tridecyl) phosphite and the like can be added.

Furthermore, the rubber-modified styrenic polymer composition of the present invention and other polymers, such as polyphenylene ether, may be mixed and used.

Hereinafter, the present invention will be specifically explained with reference to Examples. The present invention is not limited to these examples.

The methods for measuring the physical properties shown in the Examples are described below.

■ Melt flow rate: Compliant with ISOR1133.

■Izotsu impact strength: Based on ASTM D256.

■ Tensile strength: Based on ASTM D638.

■ Gloss: Molding the Danher test piece under the conditions of molding temperature 220°C and mold temperature 60°C, and 4c+n from the gate side.
Measured in accordance with JIS Z8741.

■ Rubber particle size: Calculated from electron micrographs and is the number average particle size.

(Example 1) In a 1042 autoclave equipped with a stirring blade and a thermometer, a mixture of 7 parts by weight of polybutadiene (Note-1), 83 parts by weight of styrene, 10 parts by weight of ethylhenzene, 0.1 parts by weight of initiator 1 (Note-2) 3 4 kg was charged and polymerization was carried out at 110°C for 4 hours with stirring, then at 130°C for 2 hours, and at 150°C for 2 hours.
Time polymerization was performed. The solid content concentration was 83.4% by weight. Put the polymerization solution in a dryer and dry at 230°C 15mm H
Unreacted styrene and ethylbenzene were removed under the conditions of g for 30 minutes to obtain a rubber-modified styrenic polymer composition.

Physical properties were measured using this polymer composition. The results are shown in Table-2.

(Example 2) Using the same equipment as in Example 1, polybutadiene (Note-1) 7 parts by weight Styrene 86 parts by weight Ethylbenzene 7 parts by weight Initiator-1 (Note-2) 0.01 part by weight After 4 kg of polymer was charged and polymerized at 110°C for 4 hours with stirring, 0°01 parts by weight of initiator-2 (Note-2) was added and the polymerization was carried out at 130°C for 2 hours and then at 150°C. Polymerization was continued and stopped when the solid content concentration was 83.2% by weight.

This polymerization solution was treated in the same manner and conditions as in Example 1,
Physical properties were measured. The results are shown in Table-2.

(Comparative Example 1) Using the same equipment as in Example 1, 4 kg of a mixture of 7 parts by weight of polybutadiene (Note-1) 85 parts by weight of styrene 8 parts by weight of ethylbenzene 0.03 parts by weight of Initiator-3 (Note-2) was charged and polymerized at 110°C for 3 hours with stirring, then at 130°C for 3 hours, then at 150°C.
Polymerization was continued at C and stopped when the solid content concentration was 83.4% by weight.

This polymerization solution was treated in the same manner and conditions as in Example 1,
Physical properties were measured. The results are shown in Table-2.

(Comparative Example 2) Using the same equipment as in Example 1, polybutadiene (Note-1) 7 parts by weight Styrene 85 parts by weight Ethylhenzene 8 parts by weight Initiator-1 (Note-2) 0.001 parts by weight Mixture 4
After polymerizing at 110°C for 2 hours with stirring, 0°03 parts by weight of initiator-2 (Note-2) was added.
Polymerization was continued at 130°C for 3 hours and then at 150°C, and was stopped when the solid content concentration was 83.5% by weight.

This polymerization solution was treated in the same manner and conditions as in Example 1,
Physical properties were measured. The results are shown in Table-2.

Note-1: Polybutadiene (NF-35 manufactured by Asahi Kasei Co., Ltd.).

Note-2= Initiator-1: C-(C1l□) b-CII-(Cll□), -CO
:OII III OC2N,, 0 Initiator with 7 repeating units.

Initiator-2: 11-bis(t-butylperoxy)cyclohetosan).

19~ It can be understood from Table 2 that the rubber-modified styrenic polymer &[l acid product of the present invention has high impact strength.

The appearance and rigidity have the same values.

The polymer compositions of Examples 1 and 2 were blended with a styrenic polymer (Squilon 693 manufactured by Asahi Kaoru Co., Ltd.) to create a polymer composition (Examples 3 and 4) with a lower content of rubbery polymer. The physical properties are shown in Table 3 below.

Comparative Examples 1 and 2 in Table 2 have the same Izot impact strength as Examples 3 and 4, but are inferior in tensile strength and appearance characteristics.

Tables 2 and 3 show that the rubber-modified styrenic polymer composition of the present invention provides high impact resistance properties at the same rubber content, and also has improved rigidity and appearance properties while maintaining impact resistance properties. It is possible to understand what it means to do something.

Next, an example in which an organic polysiloxane is further blended into the rubber-modified styrenic polymer composition of the present invention will be described below.

(Example 5) Polybutadiene (Note-1) 7 parts by weight styrene was placed in an IOl autoclave equipped with a stirring blade and a thermometer.
83 parts by weight Ethylbenzene 10 parts by weight Initiator-1 (Note-2) 0.1 parts by weight Mixture 4k
After polymerization was carried out at 110°C for 4 hours and 3 hours with stirring, polymerization was carried out at 130°C for 2 hours and at 150''C for 2 hours.The solid content concentration was 83.3% by weight. At this time, the particle size of the rubbery polymer dispersed particles was controlled by changing the stirring number.The polymerization solution was placed in a dryer, and unreacted styrene, unreacted styrene, Ethylbenzene was removed to obtain a rubber-modified styrenic polymer composition.

0.01 part by weight of silicone oil is added per 100 parts by weight of the rubber-modified styrenic polymer composition, and the mixture is pelletized using an extruder. Physical properties were measured using this pelletized polymer composition. The results are shown in Table 4.

(Example 6) Using the same equipment as in Example 5, a mixture of polybutadiene (Note-1) 7 parts by weight Styrene 86 parts by weight Ethylbenzene 7 parts by weight Initiator 2 (Note-2) 0.01 parts by weight 4k
After polymerization was carried out at 110°C for 4 hours with stirring, 0°01 parts by weight of initiator-2 (Note-2) was added, and 1
Polymerization was continued at 30°C for 2 hours and then at 50°C, and was stopped when the solid content concentration was 83.6% by weight. The diameter of the dispersed particles of the rubbery polymer was controlled by changing the stirring number in the same manner as in Example 5.

The polymerization solution was treated in the same manner and under the same conditions as in Example 5, and its physical properties were measured. The results are shown in Table 4.

(Comparative Example 3) Using the same equipment as in Example 5, polybutadiene (Note-1) 7 parts by weight Styrene 85 parts by weight Ethylbenzene 8 parts by weight Initiator-2 (Note-2) 0.03 parts by weight Mixture 4
kg, polymerization was carried out at 110°C for 3 hours with stirring, then continued at 130°C for 3 hours, then at 150"C, and the polymerization was stopped when the solid content concentration was 83.1% by weight. The diameter of the dispersed particles of the rubbery polymer was controlled by changing the stirring number in the same manner as in Example 5.

The polymerization solution was treated in the same manner and under the same conditions as in Example 5, and its physical properties were measured. The results are shown in Table 4.

(Comparative Example 4) Using the same equipment as in Example 5, a mixture of polybutadiene (Note-1) 7 parts by weight Styrene 85 parts by weight Ethylhenzene 8 parts by weight Initiator 2 (Note-2) 0.001 parts by weight 4k
After polymerization was carried out at 110°C for 2 hours with stirring, 0°03 parts by weight of initiator-2 (Note-2) was added, and 1
Polymerization was continued at 30°C for 3 hours and then at 150°C, and was stopped when the solid content concentration was 83.3% by weight. The diameter of the dispersed particles of the rubbery polymer was controlled by changing the stirring number in the same manner as in Example 5.

The polymerization solution was treated in the same manner and under the same conditions as in Example 5, and its physical properties were measured. The results are shown in Table 4.

Figure 2.3 illustrates the relationship between the average particle diameter of the rubbery polymer and the Izot impact strength value in Table 4, and the relationship between the Izot impact strength value and the appearance.

From Table 4 and Figures 2 and 3, it is clear that the rubber-modified styrenic polymer composition blended with organic polysiloxane has high Izont impact strength, especially as the average particle diameter of the rubbery polymer becomes smaller. It can be seen that the effect is greater.

In addition, the gloss value is higher than that of the comparative example at the same particle size.

It can be seen that the balance between impact strength and gloss is significantly improved compared to the comparative example.

(Effects of the Invention) In the present invention, by giving the styrenic polymer constituting the rubber-modified styrenic polymer composition a new specific structure, it is possible to achieve
Impact resistance is significantly improved.

Furthermore, by blending an organic polysiloxane into this polymer composition, it is possible to obtain a product that is excellent not only in impact resistance but also in appearance.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing a cross section (taken by an electron micrograph) of dispersed particles of the rubber-modified styrenic polymer composition of the present invention. Figures 2 and 3 are graphs showing the relationship between the average particle diameter of a rubbery polymer and impact strength, and the relationship between gloss and impact strength, respectively. (1 idiot) 8 Procedural amendment September 20, 1989

Claims (1)

[Scope of Claims] A rubber-modified styrenic polymer composition containing a rubber-like polymer as dispersed particles, comprising: (a) dispersed particles made of a rubber-like polymer; (b) general formula; (A) ▲ mathematical formula; , chemical formulas, tables, etc.▼ (In the formula, l, m, n are integers from 1 to 20, R_1,
R_2, R_3, and R_4 are hydrogen, an alkyl group having 1 to 5 carbon atoms, a cyclohexyl group, or a phenyl group, and at least one of them is an alkyl group having 2 to 5 carbon atoms. ) and (B) ▲ Numerical formulas, chemical formulas, tables, etc. ▼ (In the formula, R_1 is hydrogen or a methyl group, and R_2 represents hydrogen or an alkyl group having 1 to 5 carbon atoms.) or a mixture of this styrenic polymer and a styrenic polymer consisting of the structural unit (B) as a continuous phase, and the ratio of the structural units in this continuous phase, A/B (mol/mol
) is 0.006 to 0.000006, and the continuous phase is 7
A rubber-modified styrenic polymer composition with excellent strength, characterized by comprising a styrenic polymer continuous phase of 5 to 99% by weight.