DE1251523C2 - THERMOPLASTIC COMPOUNDS FOR THE MANUFACTURE OF IMPACT-RESISTANT MOLDED BODIES FROM ISOTACTIC POLYPROPYLENE AND LOW PRESSURE POLYAETHYLENE - Google Patents

Description

I 251

greatly improved tear strength and tear strength. Here with is of particular advantage that the strength lengthways / crossways is approximately the same, which is the case with foils of isotactic polypropylene due to the orientation that occurs in film manufacture, not the Case is. Hollow bodies (e.g. bottles) produced from the mixtures according to the invention show excellent drop resistance even at low temperatures. The same also applies to the impact strength of injection molded articles.

Another advantage of the molding compositions according to the invention is that articles produced therefrom have the same Stabilization results in significantly better heat retention times than those made from isotactic polypropylene Parts. .

In this context, low-pressure polyethylene is understood to mean a polyethylene which, using the so-called Ziegler catalyst was produced, i.e. catalyst systems made from compounds of I. to IH. Group of the Periodic Table, in particular aluminum alkyl compounds, and compounds of IV. Bjs VI. Neberigruppe of the periodic table including thorium and uranium, especially titanium halides. The so-called Phillips process using chromium oxide-containing catalysts can also be used Manufactured polyethylene come into consideration.

Example·!

, o Isotactic polypropylene powder was in a Schneilauf mixer with various amounts of polyethylene powder with the addition of known stabilizers Mixed for 10 minutes. After granulation of the mixtures obtained, the granules became

, ₅ test specimens produced for mechanical testing. The polyethylene used is a low-pressure polyethylene with a density of 0.960 and a reduced solution viscosity >) _re <i - 2.0. The product had a methyl group content of less

_ao as 1/1000 carbon atoms. The inconsistency U was 1.

The results obtained are compared in Table 1 with the results for isotactic polypropylene.

table

mixture tensile strenght PP i PÄ kp / cm ^z 7th 360 100 In 360 95 358 90 : 5 355 80 10 348 70 20th 336 50 30th 50

■ Ball indentation hardness Cold break point *) Heat resistance Days at 145 "C kg / cm ² C. 780/710 1/4 90 785/717 14/18 115 778/704 18 / - 21 118 770/700 24 / -28 127 756/688 29/34 127 732/666 35/39 136

*) The cold break point, a measure of the impact strength, indicates the temperature at which 50 or 100 "/ ,, of the sprayed Unnotched standard small rods can be broken by a 10 cmkg pendulum.

Example 2

Isotactic polypropylene was combined with polyethylene with a density of 0.951 and a reduced solution viscosity nre.ii 3.7 - as described in Example 1

mixed. The results can be found in Table 2. The product had a methyl group content of 2.0 / 1000 carbon atoms. The inconsistency (J was 5 to 6.

PP mixture
PA j 5 tensile strenght % 10 , kp / cm ² 100 I) /
In 360 95 358 90 354 80 20th 340 70 30th 322 50 50 295

Table 2 Cold break point Heat resistance Ball pressure hardness Days at 145'C C. kg / cm ² 1/4 90 780/710 -11/14 105 776/705 17/20 108 768/700 23 / -28 112 742/684 27/31 111 725/663 33 / -36 Il 7 705/645

For comparison, experiments with the addition of polyethylene show their properties outside of those specified Range, the following results:

Data of the used
Low pressure polyethylene

Diphts

U

oyioooc.

rypA Type B 2.22 2.0 0.960 0.961 4th 2 0.5 1.6

yp c Type D 3.0 2.8 0.952 0.950 4th 7th 3.6 7.2

5 6

Test results of the mixtures of polypropylene (PP) with low pressure polyethylene (PE)

mixture tensile strenght
kp / cm ⁵ Ball indentation hardness
kg / cm ² Cold break point
C. Heat resistance
Days at 145rC Type a 95 5
80 20
50 50 357
340
310 780/710
750/682
. 705/639 - 21- 4
- 4 / - 8
-10 / 14 100
100
110 Type B 95 5
80 20
50 50 355
340
315 776/705
752/680
715/648 1/4
- 3 / - 6
- 7/10 90
95
98 TypeC 95 5
80 20
50 50 349
318
283 778/706
725/652
695/627 3 / - 6
- 7/10
■ 10/13 95
103
109 Type D 95 5
80 20
50 50 352
320
280 780/709
731/655
696/629 -: 2 / - 5
8/12
14/17 92
104
112

Claims (1)

It is also known during polymerization _{Claim by} p rO py) _s intermittently low ethylene levels initiate and thereby increased polymers Thermoplastic compositions for the production of impact resistance. However, the solid molded body made of isotactic polypropylene 5 is not easy to handle. The addition of about 1 to 50 percent by weight, based on polyethylene to polypropylene, has already been considered; measured in propylene with polyethylene have a milky appearance p-xylene at 110 "C, of at least 1.8 and have low strengths,
of polyethylene, either a) with a density of the polypropylene low-pressure polyethylene with about 0.95, a methyl group content of up to my molecular weight 600000-1500 000, 5 CH _3/1000 carbon atoms and a molecular weight which _η Τ _{€ (ι-} Corresponds to values of about 12 and above, adding distribution,..., Leads to improved cold properties , J ₅ shafts, but experience other mechanical I ^w l \ properties such as tensile strength, limit bending ■ M _n I tension and ball indentation hardness, an essential one from 5 to 8 or b) with a density of about 8 ^Minderun (French Patent 1,284,300). 0.96, a methyl group content of less than ^{addition makes experi} g ^s 8 ^{emäß when z "s} ATZ from 1 CH3 / IOOO C-atoms and a molecular weight polyethylenes ²⁰ with such high molecular weights, the distribution aforesaid poor compatibility with polypropylene, eg by strong so-called fish-eye formation in ^ ^w I j prefabricated noticeable. M _n J It has now surprisingly been found that _a5 by adding low-pressure polyethylene certain of ^; 2.5 or less contain properties with good miscibility of the components an impact-resistant polypropylene is obtained. Unexpectedly are in contrast to those after the known processes produced impact-resistant poly , propylenes even with an addition of 20% poly ethylene the mechanical properties of the invented It is known that isotactic polypropylene of the impact-modified polypropylene mixture according to the invention is second to those of isotactic polypropylene because of its high transformation point. Order only very well at low temperatures Even with higher additives of up to 50%, the low impact strength is exhibited. For example, molded parts made from iso-mechanical properties, ie tactical polypropylene, e.g. B. ^{the values for the} tensile strength and ball indentation hardness injection molded ^{articles or hollow bodies, at temperatures for all} compared to those of the unmixed polyproum and below 0 ⁰ C very brittle and break under the This property makes it difficult to use poly-propylene in the examples below for many areas in which in addition to the high borrowed in the preferred embodiment of the at-crystallite melting range of the polypropylene used in example I. about 160 to 170 ^° C., also a strength. The subject of the invention are thermoplastics low temperatures is essential. As an example of masses for the production of impact-resistant molded bodies from the packaging of liquids, the _4S isotactic polypropylene and about 1 to 50 years after the filling should still be sterilized. Weight percentage, based on the total mixture, of a sterilization of low-pressure polyethylene in polypropylene bottles, characterized in that the high crystallite em enables a reduced solution viscosity, measured in the melting range of the polypropylene. If P-Xtfol is stored at UO ⁰ C of at least 1.8 but filled bottles then at temperature ₀ polyethylene either a) with a density of about doors around and below Ö ° C (e.g. in a cold store), °. ^{95> EMEM} methyl group content of up to 5 CH _3/1000 there is a risk that the bottles at unforeseen carbon atoms and a molecular weight distribution
shatter with careful treatment. / M _w For these reasons, it is of great benefit to \ M _n when 'a polypropylene verän- ₅₅ as the can, that - while maintaining 5 to 8 or b) with a density of "about 0.96, its good mechanical properties at high a methyl group content of less than 1 CH ₃ / temperatures - Has good impact strength even at 1000 C atoms and a molecular weight distribution at low temperatures. It is known that an impact-resistant polypro- g ₀ / m _w \ pylene by copolymerization of propylene with \ Λ / ~~ / other olefins or through admixture of polymers (e.g. of polyisobutylene or certain of 2.5 or less.
Ethylene-propylene copolymers). The use of very linear is preferred Impact-resistant polypropylenes produced in this way g ₅ polyethylene with a narrow molecular weight distribution, however, have the disadvantage that the good mechanical properties according to b). Properties of isotactic polypropylene strongly show films made from these blends to be humiliated. compared to those made of isotactic polypropylene one