CS199383B1 - Direct for making products from polyolefins,especially polyethylene having enhanced photodegradation sensitivity - Google Patents

Description

BACKGROUND OF THE INVENTION The present invention relates to a composition for making articles of polyolefins, in particular polyethylene, with increased sensitivity to photodegradation. Products made of these materials are able to disintegrate spontaneously under atmospheric conditions such as sunlight and airborne oxygen ·

The increasing production and use of plastic wrappers, fibers and containers, especially polyolefins, leads to the need to address the ecologically serious issue of removing these products after use. One possibility is to manufacture these articles from degradable materials. For this purpose, either polymeric substances which are capable of degrading themselves can be used, or degrading additives can be added to commercially available plastics. This latter option is more technologically advantageous. The degrading effect of these substances is known: organic compounds containing transition metal ions such as ferric dibutyldithiocarbamate; aromatic compounds and fused rings such as phenanthrene; aromatic ketones such as benzophenone; 1,4-benzoquinone derivatives. In addition to their specific advantages, all these substances also have a number of disadvantages: metal-containing substances usually color the substrate and often cause it to degrade even during heat treatment; aromatic hydrocarbons are poorly effective for degrading polyolefins and there is a potential risk of carcinogenic effects; benzophenone mainly absorbs that part of the shortwave radiation that no longer falls on the ground and is therefore not fully utilized and its efficiency is lower; 1,4-benzoquinone derivatives

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1SS 3B3 elce use much better energy of solar radiation, but they are mostly unstable on light - except anthraquinone, which is almost insoluble in non-polar environment, is poorly tolerated and polyolefins and its efficiency is not fully utilized. Water can also be washed out gradually from the substrate. The use of 2-ethylenehraebinone in iron (III) dibutyldithiocarbamate (U.S. Pat. No. 3,941,759) is also known. This mixture is colored and therefore cannot be used for colorless products. U.S. Pat. No. 3,767,638 discloses the use of 2-tert-butylanthraohinone in which there is no apparent advantage of this flyer over anthraohinone, either in terms of efficacy or elution. It has been shown that the substitution of the 9,10-anthraquinone skeleton at the 2-position with a branched alkyl does not meet all the expected assumptions and overall efficiency is lower (see table).

SUMMARY OF THE INVENTION The present invention is directed to the manufacture of polyolefin products, in particular polyethylene, and to enhanced photodegradation sensitivity containing polyolefin and optionally specific additives containing from about 0.01% to about 10% of 2-alkyl-9,10-anthraquinone (prodegradant) of the formula

wherein R is a primary alkyl having 2 to 10 carbon atoms.

As biodegradable additives, it is preferable to use antioxidants, anti-drugs, herbicides, growth promoters, other biodegradation accelerating additives, processing additives, coloring agents, etc. The amount and type of these additives are selected according to the desired use and effect.

The primary alkyl group does not adversely affect the photoohemic properties of anthraquinone, but it dramatically increases the solubility in alkane and the tolerance of β polyolefins. The increased degrading activity compared to anthrachlone is shown in the table below.

In the following, the invention is explained in more detail by way of example.

Example 1

An acetone solution of 2 g of 2-ethylanthraohinone was added to 200 g of non-stabilized polyethylene of the Czechoslovak production, Bralen Na 7-25. The mixture was mixed and after vacuum removal of solvent completely homogenized in a high-speed mixer under an inert atmosphere. The prepared mixture was made with a conventional processing foil of 0.12 mm thickness. These films were subjected to accelerated aging in Xenoteet 150 and the change in carbonyl group content was monitored as an indication of aging. Data not measured after 312 hours of exposure are shown in the table.

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Example 2

The procedure was the same as in Example 1, except that 2-butylanthraquinone was used in the same amount by weight instead of 2-ethylanthraquinone.

Table

Increment of absorbanoe at 1710 cm ^3, in polyethylene containing 1% prodegradant, over 312 hours of exposure to Xenotest 130.

Example Prodegradant Growth absorbanoe Anthrachinon 0.612 2-Isopropylanthraquinone 0.730 - 2-tero.Butylanthrachinone 0,851 1 2-Et hylanthraohinone 0.994 2 2-Butylanthraquinone 1,053

SUBJECT OF THE INVENTION

Claims (1)

SUBJECT OF THE INVENTION A composition for making polyolefin products, in particular polyethylene, and having enhanced photo-degradation sensitivity containing polyolefin and optionally specific additives, characterized in that it contains from 0.01 to 10% of 2-alkyl-9,10-anthraquinone of the formula wherein R is a primary alkyl containing 2 to 10 carbon atoms.