CS89891A3 - Process for preparing polyolefins uv stabilizers - Google Patents

Description

Process for the production of UV stabilizer polyolefinfl

Technical field

BACKGROUND OF THE INVENTION This invention relates to a process for the production of a polyolefin UV stabilizer. Tytp stabilized polyolefins are preferably used for agricultural films and roof coatings.

State of the art

The usefulness of polymers depends, among other things, on UV-radiation stability. Especially in the case of polyolefins, UV resistance plays a major role

It is known that by incorporating 4-hydroxy- or 4-amino-2,2'-6,6 * -tetramethylpiperidine spatial amines into the polymer, the UV-resistance is significantly increased. and its good solubility to the duke. In doing so, the molecular weight of the spatial piperidines is increased by crosslinking. In this process, products with low vapor pressure and low water solubility are achieved.

It is also known that 4-amino-2,2,6,6-tetramethylpiperidine and 4-hydroxy-2,2,6,6-tetramethylpiperidine react with acrylic acid on said amino or piperidine ester (FE Karrer Makrom Chem® 181 (1980) 595 “633). ·

A homopolymerized and copolymerized 2,2,6,6-tetramethylpiperidyl ester of acrylic acid (USP 294,949) is known, designed as a comonomer of styrene, acrylonitrile, ethylcrystalline ester and ethyl acetate.

The disadvantage of many of these copolymers is that on the basis of; their polar character has limited polyolefin compatibility, so their effectiveness will definitely be reduced. ] i

Particularly good stabilization of polyolefins against UV radiation is achieved by a polymeric non-degradable light having a non-polar carrier chain as possible.

These products are formed by re-esterifying the copolymer ethylene ester of 4-hydroxy-2,2,6,6,6-tetramethylpiperidine (EP 00 63 544).

Similarly, the non-light-degradable polymer mass is obtained by copolymerizing ethylene with acrylic acid 2,2,2,6,6-tetramethylpiperidyl ester (USP 4,294,940). In JP 63-101 455 it is proposed to graft to the polyolefin maleic anhydride and to react with the 4-hydroxy or 4-amino-2,2,6,6-tetramethylpiperidine graft product obtained. A disadvantage of this known process for the production of a UV stabilizer with a similar polyethylene carrier chain is the lower production efficiency. Very many steps are required for the ester variant, which is in the way of technical realization. Similarly, the variant with maleic anhydride grafting on polymers is similar. In copolymerization of 2,2,6,6 * -tetramethylperidyl acrylic ester with ethylene, higher investment costs for high pressure equipment are required, which is expensive for low production.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a polymeric stabilizer which, by incorporating it into polyolefins, imparts a high UV resistance to the polyolefins, has a low washout effect due to good polymer compatibility and is industrially obtainable. The invention solves this problem from the basis of the possibilities and steps of using high pressure techniques by fixing spatial amines to polymer chains, thereby achieving high quality UV stabilizer for polyolefins. SUMMARY OF THE INVENTION 100% by weight of the wax to high molecular weight polyolefins with 0.5 to 100 parts by weight of the acrylic or methacrylic acid -2,2 / 6,6 * - tetramethylpiperidyl ester are homogenized in the melt and in the presence of 0, A 05 to 0.5 weight percent of initiator-forming radicals at 100 ° C to 200 ° C are subjected to a crosslinking reaction.

Polyethylene or ethylene-vinylate copolymer is preferably used as the paraffinized to high molecular weight polyolefins. Preferably, 10 to 30 parts by weight of -2,2,6,6 * - tetramethylpiperidine ester of acrylic acid or methacrylate is also used.

It is most advantageous to obtain a reaction of waxy low molecular weight polymers having a molecular weight in the range of 1500 to 10,000 with piperidyl acrylate in a mixer, while reacting high molecular weight polymers having a molecular weight of over 20,000 in an extruder or kneading machine.

Typical polymer initiators are used as initiator radicals. The choice of initiator depends on its half-life at the indicated reaction temperature.

According to the invention, the crosslinked polymers produced are incorporated in an amount of 0.1 to 1 weight percent, preferably 0.2 to 0.4 weight percent, to the stabilized polyolefin. Examples ____________ . The invention is further illustrated by the following examples. . - - Example 1 i

700 g of polyethylene wax is melted in a 2 L argon flushing and vacuum degassing vessel (Mn 1840, < = >

Mw 7240) under argon purge and 300 g of -2,2,6,6-tetramethylpiperidyl acrylic acid are added. Add 4 g of tert when mixed at 120 ° C. butyl perbenzoate and after 30 minutes the temperature was increased to 165 ° C. The sample is then degassed for half an hour at 130 to 670 Pa and 165 ° C.

Content ; piperidine groups of 1.41 mol / kg

Mn 1280 g / mol

Mw 5020 g / mol Example 2 'and Example 2 are carried out analogously to Example 1. Addition; with 800 g of polyethylene wax and 200 g of 2,2,6,6,6-tetramethylpiperidyl acrylic acid. 'y

Piperidine content of 0.92 mol / kg Μ150 g / mol 5

Example 77 Example 3 is carried out analogously to Example 1. Addition? with 900 g of polyethylene wax and 100 g of acrylic acid 2,2,6,6,6-tetramethyl-5-piperidyl ester. O ob ·, 4 · v · »4. · * Λ" »** 4/3 4 A Ί λΊ / s VUOCU1 Ρ, Ο.Ιψ ± η I ^ xpcx XU4.1IU VjTV U1V4./ Xk.5 Iη I53O g / mol

Mw 10200 g / mol Example 4 Example 4 was carried out analogously to Example 1 · Ethylene vinyl acetate copolymer with 25.5% w / w vinyl acetate (Mn 2750, Mw 7400) was added instead of polyethylene wax.

Content .. groups.:. piperidine 1.41 mol / kg

Mn 2430 g / mol

Mw 6850 g / mol Example 5 32 g of polyethylene (Mn 21500, Mw 27700) are melted under argon flushing in a kneading chamber at 180 ° C and 8 g of 1, 2, 6, 6; * - tetramethylpiperidyl acrylic acid is added and 150 mg tert. - feutylperhenzoate and knead for 5 minutes at 180 ° C

The content of> groups of piperidine 0.92 mol / kg

Mn-17900 g / mol

Mw 79600 g / mol Example 6 Example 6 is carried out analogously to Example 5 o 28 g of polyethylene and 12 g of 2,2,6,6,6-tetramethylpiperidyl acrylic acid are added.

Content \ ·. groups. . piperidine 1.41 mol / kg

Mn 17900 g / mol

Mw 65200 g / mol

EXAMPLE 7 Example 7 was carried out analogously to Example 5. Instead of ethylene ethylene vinyl acetate copolymer with 24.5% vinylacetate (Mn 15200, Mw 51700) was added. and

Piperidine content of 0.92 mol / kg

Mn 23800 g / mol Example 8

Testing the Sample of Examples 1 to 7. 1. Treatment in Polyethylene 4 g of polyethylene are melted under argon propellant at 180 ° C in a kneading chamber and 0.15% or 0.3% by weight of the crosslinking product produced is added. "! to '7 and knead. In the same procedure, a blind test is performed.

For comparison, a poly (2,2,2,6,6 * -tetramethylpiperidine-1,4-dihydroxysuccinyl oxy-ethylene) type stabilizer is treated at a concentration of 0.15 to 0.3 weight percent. 2. Production of a test film

The sample with added stabilizer is pressed into a foil of 0.05 mm thickness. 3. Testing

The film is tested for UV stability with a sprinkler. The test is considered complete when the CO band reaches 0,1 at 1815 cm.

4 · Test Results »Stabilizer Added Amount of Effective Factors ^ -P? ... - _ blind test 0 0 1 1 0.15 2.13 4.2 0.30 <> 27 6.5. 2 0,15 1,42 4,0 0,30 '2,84 5,3' 3 0,15 0,71 3,0 0,30 1,42 4,2 i · / 4 0,15 2,13 4.3 0.30 4.27 6.6 5 0.15 1.42 3.8 0.30 2.84 5.1 6 0.15 2.13 4.7 0.30 4.27 6.4 7 0.15 1.42 4.3 0.30 2.84 5.4. Comparative 0.15 5.8 3.4 Test 0.30 11.6 5.1

Claims (1)

Original document published without claims.