IL43981A

IL43981A - Polymeric mixtures for the preparation of films for use in agriculture

Info

Publication number: IL43981A
Application number: IL4398174A
Authority: IL
Original assignee: Ethylene Plastique Sa
Priority date: 1973-01-15
Filing date: 1974-01-09
Publication date: 1977-01-31
Also published as: IT1046438B; JPS49105843A; JPS575825B2

Description

Polymeric mixtures for the preparation of films for use in agriculture ETHYLENE PLASTIQUE 42143 The present invention relates to new mixtures suitable for the preparation of for agricultural based on plastics and to the films Films for agricultural use have been described in Israel Patent made of plastics material containing more than of a polymer constituted by polyethylene of density lower than or of an acetate polymer and from 1 to of at least one filler of fine chosen from silica and aluminium Films have also been described which in addition to the filler described from by weight with respect to the plastics of a suitably chosen wetting such a wetting agent is chosen from the products of condensation of epoxide with long chain aliphatic compounds comprising at least one amine or amide reactive function and the esters of or to a degree and of aliphatic acids este i than and ably lower than Although the films prepared according to Israel Patent have in fac excellent properties which render them particularly suitable for use as agricultural it has been found that their manufacture presented certain difficulties in view of the liberation of hydration water from the hydrated alumina in the course of this French patent specification describes the use of as an additive and specifically mentions perlite and These two have slightly different formulae and both contain ible amounts of these are mixed with the polymers according to the there is formation and liberation of The thus relates to a new of producing agricultural use having a good transparency solar a suitable opacity to infrared radiation emitted by the ground and having good these films moreover being very simple to The films according to the invention are characterised in that an anhydrous is used as additive at about 1 to weight with respect to the In it has found that anhydrous silicate can advantageously replace the hydrated alumina and the heretofore used silica on the one hand the properties of absorption of infrared radiation by this are to those obtained with the previously recommended on the other the films obtained have mechanical and optical properties which are as high as those observed when using the previously recommended the preparation of the film is much easier in view of the absence of any liberation of water during the invention relates to a specific process of preparing films containing anhydrous This process is characterised in that the operation is effected in two steps in a first a homogeneous mixture is made from the plastics material to be used and anhydrous said mixture containing at least by weight of said in a second the mixture is of the product obtained in the first stage and of the plastics material to be the relative proportions of these two compounds being suitably chosen so as to obtain a final product containing Of the made in the course of the two steps of the process of the invention imply the fusion of the plastics material so as to obtain perfectly homogeneous A preferred embodiment of the invention is described in an internal mixer working at a temperature of 4 kg of a polyethylene of density and of a grade 2 are homogenized with kg of an marketed under the name of in the second 1 kg of previously prepared mixture and 8 kg of the same polyethylene as that used for preparing preceding mixture are homogenized in an internal functioning at a temperature of the order of a product is thus obtained which is easily extruded to form a film and which contains about by weight of anhydrous Of a certain quantity of a suitable wetting agent such one of those mentioned above may be added to the mixtures made according to the insufficientOCRQuality

Claims

1. Polymeric mixtures suitable for the preparation of films for agricultural use, characterised in that they contain: - at least 80% of a polyme chosen from polyethylenes having a density lower than 0,94 and ethylene-vinyl acetate copolymers ; - from 1 to 20% by weight of anhydrous alumlno-sillcate.

2. Mixtures according to Claim 1, characterised in that they contain from 0.5 to 5% by weight, with respect to the plastics material of a wetting agent chosen from the condensation products of epoxide with long chain aliphatic compounds comprising at least one acid, amine or amide reactive function, and the esters of polyalcohols or polyaminoalcohols and of aliphatic acids esterified to a degree lower than 70% and preferably lower than 50%.

3. Process for making mixtures according to either one of Claims 1 and 2, characterised in that a mixture of the polymer and anhydrous alumino-sllicate containing at least 50% by weight of anhydrous alumino-silicate is homogenised, and the mixture obtained is then homogenised with a sufficient quantity of said polymer to obtain a final product containing the desired quantity of anhydrous alumino-sllicate.

4. Intermediate products for forming the mixtures claimed in the preceding claims, characterised in that they contain less than 50% by weight of a polymer chosen from polyethylenes having a density lower than 0.94 and ethylene-vinyl acetate copolymers, and at least 50% by weight of anhydrous alumino-sillcate.