CA1231596A

CA1231596A - Plastic sheeting with antislipping means and use thereof as a protective cover for timber stacks

Info

Publication number: CA1231596A
Application number: CA000482751A
Authority: CA
Inventors: Jan A.B. Andersson
Original assignee: Icopal AB
Current assignee: BMI Sverige AB
Priority date: 1984-06-06
Filing date: 1985-05-29
Publication date: 1988-01-19
Also published as: FI852258A0; SE8403034L; FI78656C; NO852252L; SE8403034D0; FI852258L; FI78656B; NO164343C; NO164343B; SE451019B

Abstract

PLASTIC SHEETING WITH ANTISLIPPING MEANS AND USE
THEREOF AS A PROTECTIVE COVER FOR TIMBER STACKS
Abstract of the Disclosure A plastic sheeting has antislipping means in the form of a discontinuous surface layer consisting of a mixture of asphalt, filler and a mixture of an ethylene butyl acrylate copolymer and bitumen. The sheeting may be an ethylene or propylene plastic sheeting. The plastic sheeting is used as a protective cover for stacks of timber.

Description

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Nowadays, the stacks of limber in timber yards are usually covered with plastic covers to prevent the timber from getting wet. Such timber stacks may have a consider-able length, for example 6 metros, a width of 5 metros and a height of 1.5 or 2 metros. Labor safety authorities require that such protective covers and plastic sheets be provided with anti slipping means, and great efforts have been made to provide suitable anti slipping means, for example by embossing the plastic sheeting or in some other manner. However, prior art plastic sheetings for this purpose nevertheless have been unable to prevent slipping accidents.
It therefore is an object of this invention to provide a plastic sheeting with improved anti slipping means. Another object of the invention is to provide such a plastic sheeting for use as a protective cover for timber stacks.
In earlier attempts at providing plastic sheetings with anti slipping means in the form of applied layers of a material having a higher friction, it was found difficult to anchor the anti slipping layer to the plastic sheeting. For timber stacks, use is made in most cases of a polyethylene sheeting which has adequate strength characteristics for such purpose. However, it is difficult to achieve satisfactory adhesion of other materials to an untreated polypropylene or polyethylene sheeting, which is only natural because polyethylene and polyp propylene frequently are used as release layers, for ,. . .

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example in connection with asphalt products, such as roofing materials. However, it has now been discovered that it is possible to provide plastic sheetings with a strongly adherent material having high anti slipping ability, if this material is formed of a special type of asphalt mix, i.e. a mixture of asphalt, filler and a mixture consisting of an ethylene bottle aerylate co-polymer and bitumen. Such an asphalt mix may be applied to a plastic sheeting, even a polyethylene or pulpier-pylon sheeting, with undiminished adhesive power also at such low temperature conditions as may occur in con-notion with protective covers for timber sleeks. The mixture of copolymer and bitumen preferably is such a mixture of ethylene bottle aerylate eopolymer and bitumen as is commercially available from BASS AGO Federal Republic of Germany, and the trademark LUCOBIT~ 121~.
According to the producer s specifications, this is a plastic material consisting of a mixture of ethylene bottle aerylate copolymer and a special bitumen. This material has the characteristics of a thermoplastic material and may be extruded, injection mounded and compression mounded by means of conventional plastic processing machines. the material is a tough elastic compound having high tensile strength, a brittleness range of below -30C, and a softening range of about 80-100C.
If such a eopolymer is mixed with steam-refined asphalt and a filler, in particular talc, there is obtained a coating compound which, in the hot state, can be spread US

on polyethylene or polypropylene sheetings in the form of individual spots or strips. In connection with such an application the free surface of the anti slipping compound may optionally be provided with a rolled-in layer of a particulate material, especially sand, although this is not necessary. Suitable mixtures of the asphalt, the talc and the said compound of ethylene bottle acrylate copolymer and special bitumen may comprise about 50%
asphalt, about 20% talc and about 30% LUCOBIT~. A compound that has proved to give a very good anti slipping pro-section on timber stacks comprises 28% LUCOBIT~, 19%
talc H200 and 53% asphalt B120 (softening point 45 C
and penetration 120 mm/10).
In the accompanying drawing Fig l is a schematic section of a timber stack covered with a plastic sheeting according to the in-mention; and Fig. 2 is a schematic section on a larger scale of a portion of the anti slipping parts of the sheeting.
Thus, Fig. l illustrates a timber stack 10, covered with a sheeting if which, in the embodiment illustrated, is provided with anti slipping spots 12 at least within those parts of the sheeting which form the upper walkway on the stack. Fig. 2 illustrates on a larger scale a section of the said anti slipping portion of the sheeting.
The sheeting if thus has elongate spots 12 of an anti-slipping material, and in the embodiment illustrated the surface of the anti slipping material 12 carries ~23~5~

a thin layer lo of sand or other particulate material.
However, such a layer is not absolutely necessary, although i-t may be advantageous because the sheeting is stored in rolled-up condition.

Claims

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A plastic sheeting with antislipping means, characterized in that the antislipping means (12) consists of an applied discontinuous layer (12) of a mixture of asphalt, filler and a mixture of ethylene copolymer and bitumen.

2. A plastic sheeting as claimed in claim 1, wherein said sheeting is an ethylene or propylene plastic sheeting.

3. A plastic sheeting as claimed in claim 1 or 2, wherein the antislipping means (12) has a surface coating (13) of particulate material.

4. A plastic sheeting as claimed in claim 1 or 2, wherein the antislipping means (12) has a surface coating (13) of sand.

5. A plastic sheeting as claimed in claim 1 or 2, wherein the asphalt is steam-refined asphalt.

6. A plastic sheeting as claimed in claim 1, wherein the antislipping means (12) has a surface coating (13) of particulate material, and wherein the asphalt is steam-refined asphalt.

7. A plastic sheeting as claimed in claim 1, 2 or 6, wherein the eythylene copolymer is a copolymer of ethylene and butyl acrylate.

8. A plastic sheeting as claimed in claim 1, 2 or 6, wherein the antislipping layer consists of a mixture of about 50% asphalt, about 20% filler and about 30% of said mixture of ethylene butyl acrylate copolymer and bitumen.

9. A plastic sheeting as claimed in claim 1, 2 or 6, shaped to provide a protective cover for stacks of timber.