DE1264048B - Process for the production of high-impact molding compositions containing styrene polymers and having a raised softening point - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

GERMAN

PATENT OFFICE

EDITORIAL

Int. Cl .:

C08f

German class: 39 b -22/06

Number:
File number:
Registration date:
Display day:

1264048
B86966IVc / 39b
May 5th 1966
March 21, 1968

Impact-resistant polystyrene is manufactured industrially by adding styrene in the presence of rubber-elastic Components, e.g. B. of polybutadiene polymerized. Here part of the styrene is on the double bonds of the polybutadiene polymerized on. In the end, mixtures are obtained that consist of Polystyrene and a graft polymer of styrene on polybutadiene. This so-called impact resistant Polystyrene generally has a rubber content between about 4 and 15 percent by weight. Of the Depending on the amount of rubber, the softening point is between about 85 and .93 C.

It is known that the homo- and copolymers of -methylstyrene have a higher softening point have than the corresponding polymers of styrene. By using -methylstyrene Instead of styrene, the softening points of styrene polymers can therefore be increased. u-Methylstyrene is difficult to polymerize radically together with styrene. It is therefore in the generally by ionic polymerization, e.g. B. with alkali metals or alkali metal hydrides as catalysts, homo- or co-polymerized. The ionic polymerization of «-Methylstyrene and styrene for However, it is not technically possible to manufacture impact-resistant polystyrene.

Attempts have already been made to determine the softening point of impact-resistant materials modified with polybutadiene To increase polystyrene by adding copolymers of «-Methylstyrene together with butadiene polymers added to the impact-resistant polystyrene (French patent 1 077 742). These well-known However, mixtures have technically unsatisfactory properties, because when they are increased the softening point, the impact resistance is reduced to a very great extent, and the long-term behavior at a certain load is insufficient.

It is also known to mix impact-resistant polystyrene modified with butadiene with polystyrene. Through this the softening point of the impact-resistant mixture is raised slightly, and one obtains a better flow behavior of the masses.

The subject of the invention is a process for the production of thermoplastic molding compositions by extruding a mixture of a styrene polymer obtained by polymerizing styrene in the presence of polybutadiene and a copolymer obtained by ionic copolymerization of methylstyrene and styrene at temperatures between 180 and 270 C and cooling the still plastic Polymer melt immediately after Ver-process for the production of impact-resistant
Molding compositions containing styrene polymers and having an increased softening point

Applicant:

Aniline & Soda Factory in Baden

Aktiengesellschaft, 6700 Ludwigshafen

Named as inventor:

Dr. Herbert Willersinn, 6700 Ludwigshafen;

Dr. Herbert Bolte, 6710 Frankenthal;

Dr. Otto Schott, 6800 Mannheim;

Dr. Klaus Bronstert, 6719 Carlsberg;

Dr. Karl Heinz Illers, 6700 Ludwigshafen

allowing the extruder to a temperature below 70 C in less than seconds, thereby characterized in that molding compositions are used which contain 2 to 10 percent by weight of polybutadiene and 1 to 20 percent by weight of copolymerized u-methylstyrene.

The process according to the invention increases the softening point of polybutadiene-modified Polystyrene increased considerably without the impact strength decreasing too much.

The modified with polybutadiene polystyrene is with a copolymer of «-Methylstyrene and Styrene mixed on an extruder. The modified with butadiene polystyrene is in the usual way Polymerization of styrene obtained in the presence of polybutadiene. The copolymer of "-Methyl-

809 519/705

Styrene and styrene are also produced in a known manner by polymerizing the monomers in the presence of ionic catalysts, e.g. B. of sodium or sodium hydride. The ratio of Monomers should be between 30:70 and 70:30.

When mixing the two components on an extruder, the mixing ratio should be selected so that that in the total mixture 2 to 10 percent by weight of the polybutadiene and 1 to 20 percent by weight of the "-Methylstyrene present in polymerized form are included.

It is very essential in the process according to the invention that the one produced on the extruder Mixing within a very short time, i. H. within about 60 seconds or less, from the high Mixture temperature, which is between 180 and 270'C, cooled to a temperature below 70 "C. will. This is because if the cooling takes place more slowly, mixtures containing the methylstyrene-styrene copolymer are obtained not homogeneously distributed in the styrene matrix of the impact-resistant polystyrene. Such products either have very poor technical properties with high softening points, especially inadequate long-term behavior and low impact or notched impact strength, or with normal impact strength no correspondingly increased softening points.

The parts mentioned in the examples are parts by weight.

example 1

A melt of an impact-resistant polystyrene (8 "/« polybutadiene containing) is with a second one ionically polymerized copolymer u-methylstyrene-styrene, 50:50, in a ratio of 90:10 at 230 "C, mixed well in an extruder.

The strand extruded from the extruder is passed through a distance of 40 cm Water bath drawn from room temperature and cools down to 65 "C within 15 seconds and becomes then granulated. For comparison, part of the extruded strand is only exposed to air, with no additional Cooling, also allowed to cool to 65 "C, which requires 3 minutes.

The two products made in this way have the following properties:

Tabel

Unity Test specification Impact resistant u-methylstyrene Mixing b) normal Polystyrene copolymer 90% impact-resistant polystyrene cooling down
(Comparison) (8% poly 50% «-Methyl- 10% u-methylstyrene copoly- butadiene styrene merisat containing) 50% styrene 24 500 kg / cm ² a) very fast
cooling down 230 Mechanical kg / cm ² DIN 53 455 13th properties % DIN 53 455 18,000 63 Modulus of elasticity ... cmkg / cm ² DIN 53 453 165 24,000 6.4 Tensile strength ¹ ) cmkg / cm ² DIN 53 453 40 0 178 Elongation at break ¹ ) .... 90 7.2 35 Impact strength ² ) ... 7.6 1.1 81 Notched impact strength ² ) 7.2 3 · 10 ² Long-term behavior Minutes Tool life with a Load of 3 · 10 3-10 175kp / cm ² 10- » Thermal 92 properties ⁰ C VDE 0302 Heat resistance age (after 91 125 89 V icat) ³ ) ⁰ C 94 On the unencumbered Fer tig part beginning ver 83 forming 93 y

¹ J sample shape: pressed standard rod.

² ) Sample shape: injection-molded standard rod.

³ ) Measured in glycol.

Example 2

The surface of the water-quenched under the conditions of Example 1 becomes a Material was completely uniform and had normal 65 impact-resistant polystyrene, which 10% polybutadiene shine, while that of the slowly cooled pro holds with an ionically produced copolymer ductile exhibited greater inhomogeneities that an α-methylstyrene-styrene, 50:50, in a ratio of 4: 1 resulted in a dull appearance. mixed on the extruder.

The products thus obtained had the following properties:

Table 2

unit Test specification ■ u-methylstyrene Mixing b) normal Impact resistant copolymer 80% impact-resistant polystyrene cooling down Polystyrene 50% «-Methyl- 20% «-Methylstyrene Copoly- (Comparison) (10% poly styrene merisat butadiene 50% styrene containing) a) very fast 26 400 kg / cm ² cooling down 265 Mechanical kg / cm ² DIN 53 455 7th properties % DIN 53 455 56. Modulus of elasticity ... cmkg / cm- DIN 53 453 17,000 24 500 6.4 Tensile strength ¹ ) cmkg / cm ² DIN 53 453 160 ■ 0 185 Elongation at break ¹ ) .... 40 7.2 29 Impact strength-) ... > 100 1.1 74 Notched impact strength ² ) 8.6 7.0 6 · 10 Long-term behavior Minutes Tool life with a Load of 180kp / cm ' 10 4- 10 ³ Thermal 94 properties C. VDE 0302 Heat form resistance (according to 125 90 V icat) ³ ) C. 90 96 On the unencumbered Fer tig part beginning ver forming 80 95

') Sample shape: pressed standard rod. ² ) Sample shape: injection-molded standard rod. ³ ) Measured in glycol.

Examples 3 to 8 r, j ι · ι -i i \ _r - c, ■ · j · ι ·

^v 35 products with increased heat resistance

Examples 3 to 8 are analogous to Examples 1 and 2. vary in composition and have fol-die Starting components and manufacture impact-resistant properties on:

Table 3 a

unit Test specification Impact resistant polystyrene, containing 10% poly
butadiene u-methylstyrene copolymer 70% 30% 8% poly
butadiene 50% "-Methyl-
styrene
30% "-Methyl-
styrene
70% 6% poly
butadiene C. u-methyl
styrene
50% Styrene Styrene B. Styrene II III A. I. Mechanical kg / cm ² DIN 53 455 161 properties % DIN 53 455 165 40 Tensile strength ¹ ) cmkg / cm ² DIN 53 453 205 40 > 100 0 Elongation at break ¹ ) .... cmkg / cm ² DIN 53 453 35 90 8.6 0 5.4 9.0 Impact strength ² ) ... 63 7.0 7.2 0.9 1.3 Notched impact strength ² ) 6.2 1.1 Long-term behavior Tool life with a Minutes 10 Load of 180kp / cm ² Thermal properties Heat form ⁰ C VDE 0302 90 resistance (according to 91 135 114 V icat) ³ ) 93 125 On the unencumbered Fer ⁰ C 80 tig part beginning ver 83 forming 86

¹ I sample shape: pressed standard rod.

Sample shape: injection-molded standard rod. ³ ) Measured in glycol.

Table 3 b

Example 3 b) normal Example 4 b) normal Example 5 b) normal Mixing cooled down *) Mixing cooled ⁴ ) Mixing cooled ⁴ ) 60% polymer C 50% polymer A 90% polymer C 40% u-methylstyrene copoly- 50% (i-methylstyrene copolymer 10% u-methylstyrene copoly- merisat I 286 merisat III 274 merisat II 204 a) from the
melt 6th a) from the
melt 15th a) from the
melt 17th cooled down 52 cooled down 34 cooled down 72 Mechanical 4.0 3.6 7.2 properties Tensile strength ¹ ) 242 252 178 Elongation at break ¹ ) 13th 23 32 Impact strength ² ) 58 103 40 99 84 96 Notched impact strength ² ) .. 4.7 3.9 7.6 Thermal properties 98 91 92 Heat resistant ability (according to V icat) ³ ) .. 105 99 97 At the unencumbered finish part beginning Verfor mung. .... 103 96 96

') Sample form: pressed standard lab.

Sample shape: injection-molded standard rod. ³ ) Measured in glycol. ⁴ ) comparison.

Table 3 c Example 6 b) normal Example 7 b) normal Example 8 b) normal Mixing cooled ⁴ ) Mixing cooled ⁴ ) Mixing cooled ⁴ ) 80% polymer B 90% polymer C 70% polymer C 20% «-Methylstyrene Copoly- 10% (i-methylstyrene copoly- 30% «-Methylstyrene Copoly- merisat II 199 merisat I merisat I a) from the
melt 13th a) from the
melt - a) from the
melt - cooled down 48 cooled down - cooled down - 4.2 - - Mechanical properties 182 172 194 Tensile strength ¹ ) 33 35 26th Elongation at break ¹ ) 62 98 84 - 64 - Impact strength ² ) 6.0 7.8 6.0 Notched impact strength ² ) .. Thermal 92 , properties enform: injected ³ ) Measured in Glycol. ⁴ ) comparison. Heat resistant 99 93 100 ability (according to V icat) ³ ) .. At the unencumbered finish part beginning Verfor 98 92 98 mung Rod. ² ) Prob he standard staff. ') Sample form: pressed standard

Claims (1)

Claim: Process for the production of thermoplastic molding compounds by extruding a mixture from one obtained by polymerizing styrene in the presence of polybutadiene Styrene polymer and a copolymer obtained by ionic copolymerization u-methylstyrene and styrene at temperatures between 180 and 270 "C and cooling the still plastic polymer melt immediately after leaving the extruder, within less than 60 seconds to a temperature below 70 ¹ C, characterized in that molding compositions are used which contain 2 to 10 percent by weight of polybutadiene and 1 to 20 percent by weight of polymerized u-methylstyrene. Considered publications:
British Patent No. 873 209. 519/705 3.68 © Bundesdruclterei Berlin