DE1149893B - Thermoplastic molding compounds made from polypropylene and ethylene-propylene copolymers - Google Patents

Description

It is known that bottles, foils and tubes can be produced from isotactic polypropylene. Such articles of polypropylene having a high crystallite melting point of about 160 to 17O ⁰ C, which is in practice essential.

On the other hand, due to the relatively high second-order thermodynamic transition point of the polypropylene (glass transition temperature), which is about -32 ° C., such articles made of polypropylene show a sharp drop in their impact and notched impact strength of about 6.0 cmkg / cm ² at +20 ⁰ C to 1.7 cmkg / cm ² at -20 ⁰ C. So there is a certain embrittlement. With liquids, e.g. B. water, filled bottles made of polypropylene, produced by the blowing process, shatter when falling from a relatively low height.

On the other hand, the use of molded structures made of polypropylene such as films, e.g. B. after The blow molding process can be made for packaging severely limited as they are as a result of linear structure of the polypropylene a clear orientation and, caused by it, a low one Show tear strength.

It is therefore of great practical interest to obtain a material for shaped structures which has both good heat resistance and good tear and impact resistance, especially at temperatures of around ⁰ ° C. and below.

High molecular weight polyethylene itself at -40 ⁰ C and below still good impact and notched impact strength, and so it stocks the opportunity to receive by mixing of such polyethylene to polypropylene in a shock resistant product. However, polypropylene and polyethylene are not very compatible with one another; Shaped structures from such a mixture have a milky appearance and low strengths.

It has now been found that these disadvantages are avoided and that polypropylene with copolymers from ethylene / propylene with 3 to 8% methyl group content is well tolerated.

The invention therefore provides thermoplastic molding compositions of polypropylene and ethylene-propylene copolymers containing polypropylene and 10 to 70 ° / _0th based on the total mixture, an ethylene-propylene copolymer with a methyl group content of 3 to 8%

Moldings produced from the molding compositions according to the invention show both excellent properties Heat resistance (see Table 1) as well as good mechanical properties at low temperatures

Thermoplastic molding compounds

made of polypropylene
and ethylene-propylene copolymers

Applicant:

Farbwerke Hoechst Aktiengesellschaft

formerly Master Lucius & Brüning,

Frankfurt / M., Brüningstr. 45

Dr. Richard Holzer, Oberursel (Taunus),

and Dr. Fritz Hörndler, Frankfurt / M.-Höchst,

have been named as inventors

(cf. Table 2), films made from the molding compositions according to the invention have increased tear resistance on.

example 1
40

Polypropylene powder was mixed in a commercial high-speed powder mixer with varying amounts Ethylene-propylene copolymer (methyl group content 3.5%) and 0.2% 4,4'-thio-bis- (6-tert-butylm-cresol) mixed intensively for 5 minutes as a stabilizer. The powder mixtures obtained were processed into granules by a conventional method and then pressed into test specimens. Tables 1 and 2 show those obtained for the moldings from the various mixtures Measured values compared with those for pure polypropylene.

309 599/343

Tabel

P. Polypropylene roduct
Ethylene propylene Melt index
Grams per 10 minutes Ball indentation hardness
In the ln * v * 2 Limit bend
tension Torsional modulus
(12O ⁰ Q % Mixed polymer
(Methyl groups (modified method
ASTM-1238-52 T, Kg / cm · '
(DIN 57302) (2O ⁰ C)
kg / cm ² kg / cm ² 100 content 3.5%)
Va Load 5 kg) 1) 90 0.03 650/584 405 264 80 10 0.05 641/579 363 227 70 20th 0.06 535/480 363 - 60 30th 0.14 511/460 317 149 50 40 0.16 430/387 278 91 40 50 0.23 393/356 - 63 30th 60 0.27 316/284 - 38 70 0.41 288/259 - -

^x ) Measured on press plates.

Tabel

product Impact strength +20 ⁰ C 0 ⁰ C -20 ⁰ C Notched impact strength +20 ⁰ C cmkg / cm ² 2.04 train Ethylene propylene cmkg / cm ² without break 31.4 10.6 5.86 DIN 53453 ¹ ) 2.14 strength Poly Mixed polymer DIN 53453 ^x ) without break without break 22.5 10.80 0 ° CI -2O ⁰ C 2.30 kg / cm ^! propylene (Methyl group
content 3.5%) without break without break 46.8 16.70 2.11 3.62 ² ) % % without break without break 69.2 16.80 2.24 5.08 282 100 . without break without break without break 20.90 3.84 5.40 263 90 10 without break without break without break 25.60 5.26 8.59 249 80 20th without break without break without break without break 7.26 10.30 231 70 30th without break without break without break 24.20 8.54 214 60 40 25.20 193 50 50 without break 158 40 60 146 30th 70

^x ) Measured on press plates.

² ) Measured on pressed test bars 25 x 3 x 1 mm.

Example 2

90 parts by weight of polypropylene (powder) were mixed intensively for 5 minutes in a fluid mixer with 10 parts by weight of copolymer of ethylene and propylene (methyl group content 8%) and 0.2% of a stabilizer. The powder mixture obtained was processed into granules by a customary method and then pressed into test specimens. These showed a ball indentation hardness, measured in accordance with DIN 57302, of 423/375 kg / cm ² . When testing the impact strength according to DIN 53453 ⁰ C occurred at 20 and O no fracture of the sample, while the notched impact strength at 20 ⁰ C 24.3 cmkg / cm ² and at 0 ⁰ C 6.3 cmkg / cm ² was.

Claims (1)

PATENT CLAIM: Thermoplastic molding compositions made from polypropylene and ethylene-propylene copolymers containing Polypropylene and 10 to 70%> based on the total mixture, of an ethylene-propylene copolymer with a methyl group content of 3 to 8%. Legacy Patents Considered:
German interpretative document No. 1 104 694. © 309 599/3 «5.