CS240010B1 - Polypropylene and light-stabilized propylene-ethylene copolymers - Google Patents

Abstract

The solution relates to polypropylene and copolymers of propylene with ethylene stabilized against light by light and thermo-oxidative stabilizers. Derivatives of 2,2,6,6 tetramethylpiperidinol or 4-amino 2,2,6,6 tetramethylpiperidine form a synergistic mixture with esters of thiodipropionic acid and 4-pentadekakis (propenyl) 2,6 dimethylphenol.

Description

(54) Polypropylene and light-stabilized propylene-ethylene copolymers

The solution relates to polypropylene and copolymers of propylene with ethylene stabilized against light by light and thermo-oxidative stabilizers. Derivatives of 2,2,6,6 tetramethylpiperidinol or 4-amino 2,2,6,6 tetramethylpiperidine form a synergistic mixture with esters of thiodipropionic acid and 4-pentadekakis (propenyl) 2,6 dimethylphenol.

240 010 (51) Int. Cl.V

C08L 23/10, C08K 13/00

240,010

The invention relates to polypropylene and copolymers of propylene with ethylene, stabilized by the emission of piperidinol derivatives or 4-amino-2,2,6,6 tetramethylpiperidine with phenolic, sulfur and phosphite stabilizers.

Products made of polypropylene and copolymers of propylene and ethylene occupy an important place in many sectors of the national economy. However, if these polymers do not contain protective stabilizing additives, they will very quickly lose their original valuable mechanical and appearance properties due to degradation processes caused by heat and light. Therefore, it is necessary to protect them with a mixture of thermo-oxidative and light stabilizers. As thermo-oxidative stabilizers, alkyl-substituted phenols, thiodipropionic acid esters and phosphorus-containing compounds are usually used. Derivatives of hydroxybenzophenone (US 3,349,588, US 4,288,631), hydroxybenzotriazole (US 4,278,589, US 4,278,590), 2,2,6,6 tetramethylpiperidinol and 4-amino-2,2,6,6 tetramethylpiperidine have proven themselves as light stabilizers.

Derivatives of 2,2,6,6-tetramethylpiperidinol and 4-amino 2,2,6,6-tetramethylpiperidine (hereinafter referred to as HALS stabilizers) significantly outperform derivatives of hydroxybenzophenone and hydroxybenzotriazole in their protective effect against the harmful effects of sunlight and are protected by a number of patents, for example US 3,640,928, US 4,021,432, US 4,08942, GB 04 4760, GB 055 486, KP 22501, IP 22997, CHO 13722, CH 592129, US 416 4480, US 33412, GB 1,415 741.

However, it has been found that their effectiveness is greatly reduced by sulfur-containing thermooxidative stabilizers, such as thiodipropionic acid esters. Therefore, sulfur-containing additives have been omitted from stabilizer mixtures containing HALS-type light stabilizers and combinations of HALS stabilizers with phenolic stabilizers are used.

- 2 - mo ua (JA 56 62835, JA 56 62839, JA 56 62840), or combinations of HALS stabilizers with phosphorus compounds (DT 26 06 026, DT 26 36 130, DT 5459 381, DE 3001 114, JA 81 62 838, JA 8162 836). Only in the case of a polypropylene-IPDM rubber polymer blend was it found (AO 231273^ that the stabilizing effect of HALS light stabilizers is not reduced in the presence of sulfur stabilizers, specifically thiodipropionic acid esters, if the concentration of thiodipropionic acid esters does not exceed 0.1% by weight.

The subject of the invention is polypropylene and copolymers of propylene with ethylene stabilized against light by light and thermal oxidation stabilizers containing lubricants and optionally carbon black or pigments, which contain 0.05 to 0.25% by weight of 4 pentadecakis (propenyl) 2,6 dimethylphenol, 0.05 to 0.20% by weight of thiodipropionic acid esters with saturated alcohols with 12 to 25 carbon atoms, 0.1 to 0.5% by weight of 2,2,6,6 tetramethylpiperidinol derivatives or 4 amino 2,2,6,6 tetramethylpiperidine or mixtures of these derivatives with hydroxybenzotriazole derivatives or hydroxybenzophenone derivatives in a weight ratio of 1:2 to 2:1 and optionally another phenolic or phosphite stabilizer in a concentration of 0.05 to 0.2% by weight based on the content of polypropylene or its copolymers. Polypropylene and copolymers of propylene with ethylene (with an ethylene content of 0.5 to 7% by weight), for the stabilization of which mixtures were used, which contain, in addition to HALS light stabilizers, a combination of the phenolic stabilizer 4-pentadekakis (propenyl) - 2,6 - dimethylphenol with thiodipropionic acid esters, have a higher resistance to the degradation effect of sunlight than stabilizing mixtures of HALS with other phenolic or phosphite stabilizers in the absence of sulfur stabilizing additives. In the above-mentioned mixture of 4-pentadekakis (propenyl) - 2,6 dimethylphenol with thiodipropionic acid esters and HALS stabilizers, an unexpected, exceptionally strong stabilizing effect occurs. In this case, as it was found, the total stabilizing mixture may contain, in addition to the listed substances, also other substituted phenols, for example 2,6 ditert. butyl-4-methylphenol, phosphorus-containing stabilizers such as tris(phenylethylphosphite) and hydroxybenzophenone or hydroxybenzotriazole derivatives.

240,010

The polypropylene with high resistance to the harmful effects of sunlight according to the present invention is prepared in a conventional manner, which can be characterized, for example, by the following procedure:

First, a powdered stabilizing concentrate (masterbatch) is prepared. The type of polymer to which the stabilizing concentrate is to be added is used. The polymer and powdered stabilizing additives are dosed into the mixer in a ratio of 60 to 80 parts by weight of polymer to 20 to 40 parts by weight of stabilizing additives. The mixture is mixed and emptied into transport containers, which are then emptied into the stabilizing concentrate tanks above the twin-screw mixers.

The stabilizing concentrate is continuously dosed from the hopper into the twin-screw mixer. At the same time, the unstabilized powdered polymer is dosed into the mixer. In the twin-screw mixer, the unstabilized polymer is thoroughly mixed with both the powdered stabilizing concentrate and the liquid stabilizing additives, which are dosed directly from the hoppers into the mixer by a pump. The intensive mixer homogenizes all components of the mixture and melts the mixture under the action of shear forces and external heat from the mixer shell into a melt that flows through the overflow into the single-screw extruder, where it reaches a temperature of 200 to 280 °C. The melt is forced by the screw through a series of screens, enters the extruder nozzle and passes under water through its openings. The solidifying polymer is chopped into granules just below the extruder head. The granules go into the granule dryer, where they are dried using their own heat and air flow.

To evaluate the light stability of the prepared polymer, a film with a thickness of 0.5 mm is extruded from the granulate. Strips measuring 40 mm x 5 am are placed in a Xenotest 450, where they are subjected to accelerated light aging, the course of which is controlled by the increase in carbonyl groups. The time required for the increase in carbonyl groups to the value Δ. CO * 0.15 is denoted as and is a measure of the stability of the sample.

The invention will be illustrated by the following examples given in Table 1.

The % given in the examples are by weight.

Abbreviations used:

F 1 : pentaerythritol tetraki (3,5-di-tert.butyl-4-hydroxyphenylpropionate)

F 2 : 4-Pentadecakis(propenyl)-2,5-dimethylphenol

240,010

- ί F 3 : 2,6-di-tert.butyl-4-methylphenol

FOS : tris £4(1'phenyl) ethylphenylj phosphorous acid ester S 1 : distearyl thiodipropionate

S 2 : diesters of thiodipropionic acid with a mixture of saturated alcohols with 16 to 23 carbon atoms

Η 1: polyester of succinic acid with N - β - hydroxyethyl2,2,6,6 - tetramethyl-4-hydroxypiperidine

H 2 : 4-(2,2,6,6 - tetramethyl) piperidinyl succinic acid amide

H 3 : A mixture of esters prepared by esterification of 2,2,6,6 - tetramethyl-4-piperidinol with stearin

H 4 : bis (2,2,6,6-tetramethyl-4-piperidinol) sebacate T : 2-(2*-hydroxy-3*-tert.butyl-5methylphenyl)-5-chlorobenztriazole

B; 2-hydroxy-4-n-octyloxybenzophenone

Examples 1 to 24 relate to stabilized polypropylene, examples 25 to 31 to a stabilized copolymer of propylene with ethylene with an ethylene content of 1.8%. All mixtures contained 0.15% calcium stearate. Mixture No. 17 contained, in addition to the additives listed in the table, 1.5% titanium dioxide and mixture No. 25 1.5% carbon black.

- r 240 010

Tab. Efficiency of HALS type light stabilizers depending on the presence of thermo-oxidative components of the stabilization mixture

.example no. stabilizer stabilizer stabilizer stabilizer IP _Y p _N species % species % species % species % hour 1 F 1 0.2 Η 1 0.2 4,200 2 F 1 0.2 H 2 0.2 4,850 3 F 2 0.2 Η 1 0.2 4,240 4 F 2 0.2 H 2 0.2 5.120 5 F 2 0.2 H 3 0.2 6,200 6 FOS 0.2 Η 1 0.2 4.210 7 FOS 0.2 H 2 0.2 4,835 ΐ 8 FOS 0.2 H 3 0.2 5.130 9 F 1 0.1 FOS 0.1 Η 1 0.2 4,350 10 F 1 0.1 FOS 0.1 H 2 0.2 4,940 11 F 2 0.1 FOS 0.1 H 1 0.2 5.110 12 F 2 0.1 FOS 0.1 H 2 0.2 5,800 13 F 1 0.1 With 1 0.15 Η 1 0.2 2,805 14 F 1 0.1 With 1 0.15 H 2 0.2 3,240 15 F 2 0.1 With 1 0.15 Η 1 0.2 5,300 16 F 2 0.1 With 1 0.15 H 2 0.2 6,480 17 F 2 0.1 With 2 0.15 H 3 0.2 7.725 18 F 2 0.1 With 1 0.15 F 3 0.1 Η 1 0.2 5.320 19 F 2 0.2 With 1 0.1 F 3 0.1 H 3 0.2 7,753 20 F 2 0.1 With 1 0.1 FOS 0.1 Η 1 0.2 5.305 21 F 2 0.2 With 1 0.1 F 3 0.1 Η 1 0.3 6,750 22 F 2 0.2 With 1 0.1 F 3 0.1 H 3 0.3 9.230 23 F 2 0.2 With 2 0.1 F 3 0.1 H 4 0.2 7,720 24 F 2 0.2 With 2 0.1 F 3 0.1 H 4 0.3 9.110 25 F 2 0.2 With 1 0.1 F 3 0.1 H 4 0.2 11,840 26 F 2 0.2 Η 1 0.2 4.355 27 F 1 0.1 With 1 0.15 Η 1 0.2 2,860 28 F 2 0.2 - Η 1 0.2 4,380 29 F 2 0.1 With 1 0.15 Η 1 0.2 5,470 30 F 2 0.2 With 1 0.1 T 0.15 H 3 0.15 7,960 31 F 2 0.2 With 1 0.1 B 0.15 H 3 0.15 8.120

The measured values show:

1. The presence of a sulfur stabilizing additive significantly reduces the effectiveness of HALS stabilizers when using pentaerythrityltetrakis (3,5-ditert.butyl-4-hydroxyphenylpropionate) (compare example 1 with 13, example 2 with 14 and example 6 and 26 with 27)

2. In contrast, when using 4-pentadekakis(propenyl)-2,6-dimethylphenol, the presence of a sulfur stabilizing additive is reflected in an increase in the effectiveness of HALS light stabilizers (compare example 3 with 15, example 4 with 16, example 5 with 17, example 28 with example 29)

3· The high efficiency of HALS stabilizers in the presence of a combination of 4-pentadekakis (propenyl) 2,6-dimethylphenol with thiodipropionic acid esters is not reduced if a hydroxy-benzotriazole or hydroxybenzophenone derivative (example 30 and 31), another phenolic stabilizer, for example 2,6-ditert.butyl-4-methylphenol (compare examples 15 to 17 with examples 18, 19) or a phosphite stabilizer (compare example 15 with example 20) was added to the stabilization mixture. Additional phenolic and phosphite stabilizers are usually added to the stabilization mixture to increase the resistance of the polymer to degradation during processing, or to achieve a higher degree of whiteness. With increasing concentration of HALS stabilizer, light stability increases (example 23 and 24)·

Claims (2)

P R E C O R E C O N E L 2 U Polypropylene and copolymers of propylene and light-stabilized ethylene with light and temoxidized stabilizers, containing lubricants and optionally carbon blacks or pigments, characterized in that they contain from 0.05 to 0.25% by weight of 4-pentadecakis (propenyl) - 2,6 dimethylphenols, 0.5 to 0.2% by weight of esters of Igrselina thiodipropionic with saturated alcohols having from 12 to 25 carbon atoms, 0.1 to 0.5% by weight of derivatives of 2,2,6,6 tetramethylpiperidinol or 4-amino-2,2,6, Or a mixture of these derivatives with hydroxybenzotriazole and / or hydroxybenzophenone derivatives in a weight ratio of 1: 2 to 2: 1 and optionally another phenolic or phosphite stabilizer in a concentration of 0.05 to 0.2% by weight based on the content of the polypropylene or its copolymers.