GB2074094A - Improvements relating to plastics laminates - Google Patents

Abstract

A laminate, for use eg in the manufacture of luggage has a first outer layer (1) formed from flexible, closed cell polyethylene and a second outer layer (2) formed from a fibrous sheet material e.g. a textured polypropylene. Between and bonded to these layers is an intermediate layer (3) of polyethylene which is less dense than the outer layer of polyethylene. The first outer layer is preferably flexible and self-supporting. The density of the intermediate layer may be 25% or less of that of the polyethylene outer layer. The layers may be bonded by flame lamination. <IMAGE>

Description

SPECIFICATION Improvements relating to laminations including plastics laminae This invention relates to laminations which include plastics laminae.

It is desirable for the material of which soft luggage is manufactured to be waterproof, hard wearing and usually to have an attractive surface appearance or texture. Leather meets these requirements but is expensive. Fabric materials have been used and have provided attractive luggage but they are not usually waterproof or sufficiently hard wearing to have a long useful life. Plastics sheet materials have also been used. Whilst such materials can satisfy the requirement of being waterproof the flexible materials used have generally not been very hard wearing, and so often they have tended to lack a finished appearance of quality. Combinations of fabrics and plastics sheet materials, the latter as linings for the fabrics, have been used and can provide a reasonable compromise towards attainment of the aforementioned requirements.The manufacture is more involved, however, than that where single sheets or layers of materials have to be worked upon, and hence usually more costly.

There is a need for a lamination of suitable materials which would meet the aforesaid requirements and could be readily worked so as to facilitate manufacture of products from the lamination.

According to the present invention a lamination is provided which comprises a first outer layer of a flexible, closed cell polyethylene, a second outer layer of a fibrous sheet material and between and bonded to the aforesaid layers a third, intermediate layer of polyethylene which is less dense than the outer polyethylene layer.

Preferably the intermediate layer is bonded to the other two layers by heating its surfaces until they are softened, and then compressing the other two layers on to the softened surfaces. The known flame lamination method may be employed.

The outer polyethylene layer is waterproof and hence the resultant lamination is waterproof. The density of the polyethylene can be selected according to the handling properties required, but the density must be hig her than that of the intermediate layer.

An embodiment of the invention will now be described by way of example and with reference to the accompanying drawings, in which: Figure 1 shows a cross-section of a lamination according to the invention, and Figure 2 shows, in cross-section, part of an article of luggage manufactured from a lamination according to the invention.

Referring to Figure 1, a lamination comprises a first outer layer 1 of a flexible, closed cell polyethylene of high density, and a second outer layer 2 of a fibrous sheet material. Between and bonded to the first and second outer layers is an intermediate layer 3 of polyethylene which is less dense than the outer polyethylene layer.

The intermediate layer is bonded to the other two layers by heating its surfaces until they are softened, and then compressing the other two layers on to the softened surfaces. As the surfaces solidify subsequently they become fixed to the other layers. A welded connection is produced between the adjacent surfaces of the two polyethylene layers, and a keyed connection is produced between the surface material of the intermediate layer3 and the fibres of the fibrous material layer 2.

Preferably for use of the lamination in the manufacture of luggage the outer polyethylene layer 1 is a flexible, closed cell polyethylene having a density such that whilst being flexible the material is also self-supporting. A suitable density has been found to be 130 gms/m2. Such material can be vacuum formed to a desired shape, for example to the shape of a shell of a suitcase; it can be stitched satisfactorily and its ceils seal on to the stitching so that the layer retains its waterproof integrity, and the material is light in weight.

The second outer layer 2 of fibrous material may be a woven fabric of synthetic or natural material, or a combination of synthetic and natural materials.

Preferably for the manufacture of luggage particularly, the layer 2 is formed of a textured polypropylene, which may be in the form of a woven fabric, which has a high resistance to damage and marking by scuffing. The texturing of the material provides an attractive appearance as well as having the functional advantages of improving the abrasive resistance of the material and improving the keying of the layer to the intermediate polyethylene layer.

Other synthetic materials may possibly be used, woven nylon or polyester for example. As mentioned, natural materials may also be used. For example leather may be used which, because it may be applied more for its appearance than for strength, may be applied very thinly and thus may not be unduly costly to use. The strength of the lamination may be provided primarily by the polyethylene outer layer 1.

The lamination can be readily worked by known processes without undue cost and without highly specialised skill. Furthermore, the lamination may be self-supporting to an extent that frames may possibly be omitted from the constructions of suitcases in which the lamination is employed, thereby avoiding the cost of the frames and their additional weight.

For use of the lamination in the manufacture of luggage it is desirable for the intermediate layer to be substantially less dense than the polyethylene outer layer. This is because increased surface tension results between the two polyethylene layers, which enhances the recovery characteristics of the lamination as a whole. The density of the intermediate layer may be 25%, or less, of that of the polyethylene outer layer.

Figure 2 shows, in section, part of a suitcase manufactured from the lamination shown in Figure 1. A channel-shaped lip member4 is fitted over and pro techs the edge of the shell 5 of the suitcase, and also serves to retain the lining 6 of the suitcase. The shell 5 may be vacuum-formed from the iamination and the lip member 4 may be in the form of an aluminium extrusion. Such a iamination is particu larly suited to the manufacture of luggage because it can be stitched satisfactorily, the cells of the first outer polyethylene layer sealing on the stitches so that the first outer layer and hence the lamination as a whole retains its waterproof integrity.

For use of the lamination in the manufacture of luggage, the lamination preferably has the first outer layer 1 of a density of 130 gmslm2,the second outer layer 2 of textured polypropylene, and the inter mediate layer3 of polyethylene of a density of 30 gms/m2. This lamination is highly suitable for use in the manufacture of luggage because: 1) it is waterproof; 2) it is rot proof as it is made entirely of synthetic materials; 3) it is extremely tough; 4) it is very light in weight and can give up to 50% saving in the weight of a suitcase as compared with a suitcase made of materials presently employed; 5) it can be stitched; 6) it is self-supporting whilst also being flexible; 7) the second outer layer presents an attractive, hard wearing external finish, and 8) the lamination can be shaped by thermoforming processes.

It will be understood that whilst special mention has been made of the applicability of the lamination to the manufacture of luggage, the lamination may have other applications.

Claims (14)

1. A lamination comprising a first outer layer of a flexible, closed cell polyethylene, a second outer layer of a fibrous sheet material and between and bonded to the aforesaid layers a third, intermediate layer of polyethylene which is less dense than the outer polyethylene layer.

2. A lamination according to Claim 1 wherein the outer polyethylene layer is of a density such that the layer is self-supporting.

3. A lamination according to Claim 2 wherein the outer polyethylene layer has a density of 130 gmslm2.

4. A lamination according to any of Claims 1 to 3 wherein the second outer layer comprises a woven fabric of natural material.

5. A lamination according to any of Claims 1 to 3 wherein the second outer layer comprises a textured fabric of synthetic material.

6. A lamination according to Claim 4 wherein the second outer layer is formed from textured polypropylene.

7. A lamination according to any of Claims 1 to 3 wherein the second outer layer comprises a woven fabric of a mixture of synthetic and natural materials.

8. A lamination according to any preceding claim wherein the intermediate layer has been bonded to the other two layers by heating its surface until they are softened and subsequently compressing the first and second layers on to the softened surfaces.

9. A lamination according to any preceding claim wherein the strength of the lamination is provided primarily by the polyethylene outer layer.

10. Alamination according to any preceding claim wherein the density of the intermediate layer is not more than 25% of that of the polyethylene outer layer.

11. A lamination according to Claim 3, or any of Claims 4 to 10 as dependent from Claim 3, wherein the intermediate layer has a density 30 gmslm2,

12. Luggage including a lamination as claimed in any preceding claim.

13. A laminate substantially as described herein with reference to and as illustrated by Figure 1 of the accompanying drawings.

14. Luggage substantially as described herein with reference to and as illustrated by Figure 2 of the accompanying drawings.