DE2034019C3 - Process for the production of hollow bodies from polyolefin molding compounds - Google Patents

Description

preferably from 1.2 to 3.8 dl / g. (Under the In the present context, the expression "approximately the same" is always understood to mean that none of the corresponding Characteristics deviate by more than ± 5% from the mean of the two characteristics concerned.)

This process makes it possible to manufacture process products which have a leather-like handle.

The polyolefin molding compositions to be used in the process according to the invention can readily obtained e.g. B. by homogeneously mixing the polyethylene with the polypropylene component in the relevant customary manner (kneader or extruder).

The polypropylene component as such can be based on can be obtained in a simple manner, assuming two well-known facts: First: At the customary polymerisation of propylene according to Ziegler - Natta - for example in toluene - arises a polypropylene, which consists of one soluble and one insoluble fraction in boiling toluene, the Intrinsic viscosity of the soluble portion is significantly lower than that of the insoluble portion. Secondly: In this customary polymerization, suitable variation of the process conditions (use molecular weight regulators, changes in temperature and pressure, modification of the catalyst system) produce a polypropylene that is entirely (i.e., both in its soluble and in its its insoluble part) has either a relatively high or a relatively low intrinsic viscosity. In In practice, you can accordingly use a polypropylene A with a total of two separate approaches - Relatively high intrinsic viscosity and a polypropylene B with - overall - relative produce low intrinsic viscosity, such that the portion of the polypropylene which is soluble in boiling toluene A has approximately the same intrinsic viscosity as the portion of the insoluble in boiling toluene Polypropylene B (the polypropylenes A and B are also as close as possible to each other Process conditions have been established, then their molecular weight distributions are then generally the same or approximately the same). Through Mixing - for example in a kneader or extruder - of the last two product components in the required amounts The polypropylene component in question can then be obtained in quantitative proportions. It goes without saying, however, that the manner in which the polypropylene component is used is not important has been manufactured, but only to the specific specification that this component has must have.

The method according to the invention can be carried out as such in a manner known per se the relevant customary devices and procedures are carried out, so that more detailed execution No need for further information.

example
It is assumed

(1) a polyethylene with a density of 0.950 g / cm ^sec and the intrinsic viscosity [η] (measured in decalin at 130 ⁰ C) 3.7 dl / g;

(2) (A) a common fine-powdered polypropylene,

which consists of a portion which is soluble and insoluble in boiling toluene. The intrinsic viscosities [η] (measured in decalin at

130 ⁰ C) are: insoluble fraction: 3.6 dl / g; soluble fraction: 2.6 dl / g;
(B) a customary other finely powdered polypropylene, which consists of a fraction which is ^{ao soluble and insoluble in boiling toluene.} the

Intrinsic viscosities [η] (measured in decalin at 130 ^° C.) are: insoluble fraction: 2.7 dl / g, soluble fraction: 1.6 dl / g.
Isolated by extraction with boiling toluene * ⁵ is the soluble portion of the polypropylene as (A) and the insoluble portion of the polypropylene as (B), whereupon these two components - are approximately their molecular weight distributions (determined by the method of gel permeation chromatography) equal - are homogenized with one another in a weight ratio of 25:75 (extruder, working temperature 220 ^° C.).

The components described under (1) and (2)

in a weight ratio of 1: 1 to one another homogenized (extruder, working temperature: 300 ⁰ C), followed by a relevant conventional device at a melt temperature of about 220 ° C, a tubular structure (outside diameter: 20 mm,

Wall thickness: 2 mm) was extruded, closed this structure in a mold (for a generally cylindrical bottle with round bottoms; Außendurchmtsser: 55 mm; content: about 250 cm ⁹⁾ and in the closed mold at a melt temperature of about 215 ⁰ C.

a bottle is inflated (wall thickness: 0.85 mm; bottle weight: 22 g).

The result is a bottle that has a significantly better, lederähnLci-ν, η handle than bottles that use analogue Manufactured using customary polyolefin molding compounds

wordcst -. ··, outer weight ratio of polyethylene: -'- '^ r », is also 1: 1.

Claims (1)

1 2 are insoluble, with both the intrinsic vis- Claim: viscosity as well as the molecular weight distribution of the soluble and insoluble parts strongly differ Process for the production of hollow bodies from other are different; In particular, the polyolefin molding compounds, which are composed of 5 intrinsic viscosity of the soluble fraction, are in particular made up of (1) polyethylene and (2) polypropylene, with less than that of the insoluble fraction. The Entman speaking from the molding compositions at a Massetempe- process products have opposite temperature 190-250 ⁰ C a tubular overall comparable other products, a range of fancy extruded this Gebildein a form includes advantages; of a certain drawback for certain arrival and in the closed mold at a mass io turn areas, however, is that the Verfahrensprotemperatur from 180 to 240 ⁰ C to the desired-products in the hands is not similar to leather anHohlkörper inflates feel marked thereby. Such a "leather-like gnff" is, however, characterized by the fact that polyolefin molding compounds are often desired, especially in the case of Hohlein, for example, as a mixture of bodies (bottles) used for cosmetics.
, ..,.,. "". . . ", _T , 15 The object of the present invention was to (1) 40 to 60 percent by weight of a polyethylene is _{based on} a method of the type defined at the outset with a density of 0.940 to 0.965 g / cm ³ and that it allows process products to be obtained with an intrinsic viscosity [η] (measured in the are loaded with the above-mentioned disadvantage does not decalin at 130 ⁰ C) of 2 to 4.5 dl / g as well as _{or in erne} bleached to a lesser extent. (2) 40 _ao to 60 weight percent of a mixture of _{It was ge} f _un to that this problem be solved a) 70 to 80 parts by weight of a polypropylene _{can if one} uses a j _s polyolefin molding compounds pylene, of which (with a weight ratio _a certain mixture of (1) a polyethylene ratio of polypropylene: toluene of 5:95) _and / ₂ \ _EMEM mixture of two spaced verweniger than 1 weight percent in (under _SCN i _e ^ which polypropylenes which differ in their Soluble-normal conditions) different from each other boiling toluene _{a5 Produces strong,} but in their ,, i £ ^sli , ^{ch is> and} . Intrinsic viscosity and its molecular weight b) 20 to 30 weight _vert a polypro- points eilung same pylens, of which (in a weight counterpart of the invention is accordingly a ratio of polypropylene: toluene of 5:95) Blow molding process for the production of hollow bodies more than 99 percent by weight in (less than _3o p _o i _yo i _e fi _n Normal conditions) boiling toluene _from ^ p _o i _yät h _y ien and (2) polypropylene, whereby one are soluble, _from ^ _6n molding compounds, at a melt temperature with the provisos, I. that the sum of the weight from 190 to 250 ° C is a tubular structure extru- percent under (1) and (2) is 100 each, diert, this structure closes in a form and in the II. That the sum of the parts by weight under a) and b) 35 closed mold at a melt temperature of each is 100, III. that the polypropylenes 180 to 240 ° C to the desired hollow body under a) and b) each approximately inflates. The process according to the invention is characterized by approximately the same molecular weight distributions in that a mixture of polyolefin molding compounds (determined by the gel permeation method) is used as the polyolefin molding compound
Chromatography) and IV. That in the Polypropylenes under a) and b) the absolute values (1) 40 to 60 percent by weight of a polyethylene the Instrinsic viscosity [η] (measured in decalin with a density of 0.940 to 0.965 g / cm ³ and a at 130 ^° C.) in each case in the range from 1 to 10 dl / g intrinsic viscosity [η] (measured in decalin at lie. 45 130 ⁰ C) from 2 to 4.5 dl / g as well as (2) 40 to 60 percent by weight of a mixture of a) 70 to 80 parts by weight of a polypropylene, of which (at a polypropylene: toluene weight ratio of 5:95) less than 1 Ge-50 weight percentage in (under normal conditions) The present invention relates to a blowing process which is soluble in boiling toluene, and
for the production of hollow bodies from polyolefin b) 20 to 30 parts by weight of a polypropylene, molding compounds which are composed of (1) poly of the (with a weight ratio of polyethylene and (2) polypropylene, the propylene: toluene being 5: 95) more than 99 Ge molding compounds at a melt temperature of 190 to 55 percent by weight in (under normal conditions) 25O ⁰ C a tubular structure extruded, this boiling toluene are soluble,
Form closes in one form and in the closed one Form at a melt temperature of 180 to 24O ⁰ C with the provisos, 1. that the sum of the weights inflates to the desired hollow body. Percentages under (1) and (2) in each case 100, II. That in the known processes of this type, the sum of the parts by weight under a) and b) each polyolefin molding compositions are used as 60, which is 100, III. that the polypropylenes under a) and b) which are customary, in particular those commercially available, each have both approximately the same intrinsic viscose types of polyethylene and of polypropylene entities and also have approximately the same molecular weight. In the case of polypropylene, these types are poly-weight distributions (determined by the propylene method, of which (at a weight ratio of 65 gel permeation chromatography) and IV. Polypropylene: toluene of 5:95) in (below normal that for the polypropylenes under a) and b) the Absobedingungen) boiling toluene is less than 10 overall lutwerte the intrinsic viscosities [η] (measured in weight percent soluble and more than 90 percent by weight decalin at 130 ⁰ C) are each in the range of 1 to 10,