CZ108395A3 - Tough thermoplastic material based on polyolefins - Google Patents

Abstract

The invention concerns a resilient thermoplastic material based on polyolephins consisting of 75 to 99% polyolephin compounds composed of polyethylene and polypropylene in a mass ratio of polyethylene to polypropylene of at least 1/1 and at most 100/1 and 1 to 25% modifying compounds composed of liquid polybutadiene with medium molar mass of 500 to 10,000 g/moles and organic peroxide.

Description

Technical field

The invention relates to a tough, thermoplastic polyolefin-based material.

State of the art

A disadvantage of some polyolefins is their relatively low toughness, which limits the scope of their applications. This is even more pronounced for mixtures of these polymers whose mechanical properties are so low that they are not of practical use. In this case there is another negative factor - mutual immiscibility resulting from the laws of thermodynamics of polymer mixtures. On the other hand, a suitably compatible blend of these polymers may exhibit high toughness while maintaining a balanced complex of other utility properties. Compatibility means a process leading to an increase in the interfacial adhesion of immiscible polymer components and thus to an improvement of the mechanical characteristics of the material, in particular the toughness. In connection with the increasing requirements for plastic waste recycling, this issue has recently been the subject of intensive research. Existing compatibilization processes use either an additive process based on the incorporation of suitable ethylene-propylene copolymers (eg according to DE 28 49 114, US 4,319,005 or US 4,567,847) or a reactive process in which free radicals (chemically or by radiation) initiating crosslinking or grafting reactions of macromolecules, as reported, for example, by Yu et al. (J. Appl. Pol. Sci., Vol. 52, 99-105; 1994).

The disadvantage of existing additive processes is the rather high concentration of compatibilizers accompanied by a decrease in the stiffness of the material - which is unfavorable for many applications. The reactive process does not have a negative effect on the stiffness of the polymer blend, but it significantly deteriorates its processing properties.

It has been found that a combined additive-reactive process based on peroxidically initiated radical reactions of low molecular weight polybutadiene with polyolefins results in a material of high toughness while maintaining sufficient stiffness, while having appropriate rheological behavior under processing conditions. The concentration of compatibilizer required to achieve the desired properties is substantially lower than the amounts of ethylene-propylene copolymers commonly used. Furthermore, it has been found that the modifying efficiency of radical reactions of low molecular weight polybutadiene with polyolefins is synergistically enhanced by the presence of an ethylene-propylene elastomeric copolymer in the mixture.

SUMMARY OF THE INVENTION

The present invention provides a tough polyolefin-based thermoplastic material consisting of 75 to 99% polyolefin component composed of polyethylene and polypropylene and 1 to 25% modification component composed of liquid polybutadiene and organic peroxide. The modification component according to the invention consists of liquid polybutadiene having an average molecular weight of 500 to 10,000 g / mol and an alkyl peroxide or acyl peroxide, or a mixture of alkyl peroxide and acyl peroxide. Further, the modifying component may comprise liquid polybutadiene having an average molecular weight of 500 to 10,000 g / mol and an ethylene-propylene elastomeric copolymer in a weight ratio of 10: 1 to 1:10 and an alkylperoxide or acylperoxide, or a mixture of alkylperoxide and acylperoxide. The content of alkyl peroxide or acyl peroxide, or a mixture of alkyl peroxide and acyl peroxide, is in the range of 0.025 to 2.5%. The polyolefinic component of the tough thermoplastic material of the present invention is preferably a low density polyethylene, or a medium density polyethylene, or a high density polyethylene, or polypropylene, and may further be a binary, ternary or quaternary blend comprising a low density polyethylene, medium density polyethylene, high density polyethylene, . The toughened thermoplastic material of the invention preferably further comprises an inorganic filler in an amount of up to 100 parts by weight per 100 parts by weight of all polymeric components of the material. The advantages of the polymeric material of the invention are illustrated in the following examples.

DETAILED DESCRIPTION OF THE INVENTION

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Example 1

Table 1 shows the composition and tensile strength of impact-incompatible binary and ternary mixtures of polyolefins (mixtures I, III, V and VII) and mixtures compatible with the effect of liquid polybutadiene and di-tert-butylproxide (mixtures II, IV, VI, and VIII) . Mixtures were prepared by stirring in a W 50EH Brabender Plastograph chamber. The chamber was allowed to cool to 190 ° C, the mixtures were stirred at a kneader speed of 60 min ^-1 for 10 min. The toughness was measured at 23 ° C according to DIN 53 448.

Toughness test specimens were made of pressed plates.

Table 1

Comparison of tensile impact strength and _e nekompatibilizovaných mixtures of polyolefins and blends compatibilized effect of liquid polybutadiene, and di-t-butylperoxide

Mixture Ingredients (%) AND II III IV IN VI VII VIII LD-PE ¹⁾ 80 78 - - 10 9.75 10 9.75 hd-pe ^{2) 3} - - 80 78 80 78 10 9.75 pp3) 20 May 19.5 20 May 19.5 10 9.75 80 78 1-PB ⁴⁾ - 2.3 - 2.3 - 2.3 - 2.3 dtbp ⁵⁾ - 0.2 - 0.2 - 0.2 - 0.2 and _€ [kJ.m ' ² ] 49 105 55 118 59 110 25 43

¹⁾ Bralen RA2-19, Slovnaft ²⁾ Liten BB 29, Chemopetrol ³⁾ Mosten 52 592, Chemopetrol ⁴⁾ Krasol LB, Rubber ⁵⁵ di-tert-butylperoxide, Fluka

Example 2

Table 2 shows the composition and tensile strength of impact-incompatible binary and ternary mixtures of polyolefins (mixtures IX, XI, XIII and XV) and mixtures compatible with the combined action of liquid polybutadiene, ethylene-propylene rubber and di-tert-butylproxide (mixtures X, XII) , XIV and XVI). Mixtures were prepared by stirring in a W 50EH Brabender Plastograph chamber. The chamber was allowed to cool to 190 ° C, the mixtures were stirred at a kneader speed of 60 min ^-1 for 10 min. Toughness test specimens were made of pressed plates.

Table 2

Comparison of Impact Tensile Strength and ₆ Uncompatible Polyolefin Compounds and Compounds Compatible by Liquid Polybutadiene, Ethylene-Propylene and Di-tert-Butyl Peroxide

Mixture Ingredients (%; X ) XI XII XIII XIV XV XVI XVII LD-PE ¹⁾ 80 76 - - 10 9.5 10 9.5 hd-pe ^{2) 3} - - 80 76 80 76 10 9.5 pp3) 20 May 19 Dec 20 May 19 Dec 10 9.5 80 76 1-PB ⁴⁾ - 2.4 - 2.4 - 2.4 - 2.4 EPDM ⁶⁵ - 2.4 - 2.4 - 2.4 - 2.4 ^{5) 6} - 0.2 - 0.2 - 0.2 - 0.2 and _e [kJ.m ' ² ] 49 121 55 133 59 126 25 57

¹⁾ Bralen RA2-19, Slovnaft ^2> Li ten BB 29, Chemopetrol ³⁾ Most 52 522, Chemopetrol ⁴⁾ Krasol LB, Rubber ⁵⁾ di-tert-butylperoxide, Fluka ⁶⁾ Buna AP 331, Hulls

Example 3

Table 3 compares the toughness of the unmodified polyolefins themselves and the toughness of the polyolefins modified by the action of liquid polybutadiene and di-tert-butylperoxide (mixtures XVIII, XX, XXII) and the effect of a combination of liquid polybutadiene, ethylene-propylene rubber and di-tert. XXI, and XXIII). The material was treated in the same manner as the mixtures given in Examples 1 and 2.

Table 3

Comparison of tensile impact strength and _e unmodified polyolefins and modified polyolefins, the effect of the liquid polybutadiene, and di-t-butylperoxide and the effect of the combination of liquid polybutadiene, ethylene-propylene rubber, and di-t-butylperoxide

Mixture Ingredients (%) XVIII XIX XX XXI XXII XXIII LD-PE1 ^> 100 97.5 95 - - - - - hd-pe ²⁾ - 100 ALIGN! 97.5 95 - pp3) - 100 ALIGN! 97.5 95 1-PB ⁴⁾ 2.3 2.4 2.3 2.4 - 2,3 2,4 epdm ⁶⁾ 2.4 - - 2.4 - 2.4 dtbp ⁵⁾ 0.2 0.2 - 0.2 0.2 - 0.2 0.2 and _e [kJ.m ' ^2] 87 128 137 103 141 156 34 53 65

¹⁾ Bralen RA2-19, Slovnaft ²⁾ Liten BB 29, Chemopetrol ³⁾ Mosten 52 592, Chemopetrol ^{4 5} Krasol LB, Rubber ⁵⁾ di-tert-butylperoxide, Fluka ⁶⁾ Buna AP 331, Hulls

Industrial applicability of the invention

The material according to the invention is suitable for a number of special applications requiring a material of high toughness and at the same time a high stiffness, for example for bumpers and spoilers of cars, safety covers of machines and the like. Recycling of mixtures of waste polyolefins for the production of building geosynthetic elements appears to be a particularly important application of the material according to the invention.

Claims (8)

CLAIMS 1. Tough polyolefin-based thermoplastic material, characterized in that it consists of 75 to 99% of a polyolefin component composed of polyethylene and polypropylene and 1 to 25% of a modification component composed of liquid polybutadiene and organic peroxide. Tough thermoplastic material according to claim 1, characterized in that the modifying component consists of liquid polybutadiene having an average molecular weight of 500 to 10,000 g / mol and an alkylperoxide or acylperoxide, or a mixture of alkylperoxide and acylperoxide. Tough thermoplastic material according to claim 1, characterized in that the modifying component comprises liquid polybutadiene having an average molecular weight of 500 to 10,000 g / mol and an ethylene-propylene elastomeric copolymer in a weight ratio of 10: 1 to 1:10 and an alkylperoxide or acylperoxide. or a mixture of alkyl peroxide and acyl peroxide. Tough thermoplastic material according to claim 2, characterized in that it contains 0.025 to 2.5% of alkyl peroxide or acyl peroxide, or a mixture of alkyl peroxide and acyl peroxide. Tough thermoplastic material according to claim 3, characterized in that it contains 0.025 to 2.5% of alkyl peroxide. or an acyl peroxide, or a mixture of an alkyl peroxide and an acyl peroxide. Tough thermoplastic material according to claim 1, characterized in that the polyolefinic component is a low-density polyethylene, or a medium-density polyethylene, or a high-density polyethylene, or polypropylene. Tough thermoplastic material according to Claim 1, characterized in that the polyolefinic component is a binary, ternary or quaternary mixture comprising low density polyethylene, medium density polyethylene, high density polyethylene and polypropylene in any ratio. Tough thermoplastic material according to claim 1, characterized in that it contains inorganic filler in an amount of up to 100 parts by weight per 100 parts by weight of all polymeric components of the material.