IE41983B1 - Flexible composite structure - Google Patents

Abstract

1525018 Laminates DYNAMIT NOBEL AG 29 Oct 1975 [24 Dec 1974] 44751/75 Heading B5N A flexible composite structure suitable for use as a resilient floor covering comprises an open-pore soft foam plastics layer covered on one side by a flexible top, wear-receiving layer formed of thermoplastic plastics material and on the opposite side by a flexible air-impermeable layer, e.g. of PVC, polyethylene, polyurethane or parchmentized paper, with a flexible reinforcement layer formed of material in fibre form, e.g. woven or non-woven glass fibre fabric, disposed within the foam plastics layer, within the top, wear-receiving layer or at the boundary between the foam plastics layer and the top, wear-receiving layer. The composite structure may be produced by applying air impermeable layer and foam layer to an endless support structure in the form of pastes which are gelled in situ and applying thereto the top wear-receiving layer either as a preformed sheet or as a paste which is gelled in situ, the reinforcement being incorporated into the layer desired. The top, wear-receiving layer which may be of PVC, polyurethane, polyethylene or natural or synthetic rubber, may have a thickness of 0À8-6 mm. and may be a single layer, e.g. a coloured or marbled pattern sheet, or a multilayer structure, comprising a patterned or embossed upper layer and an unpatterned or printed film lower layer. The foam layer may have a thickness of 0À5-8 mm. and may be of PVC, polyurethane or polyethylene and the air impermeable layer may have a thickness of 0À05-0À5 mm. A foam layer may also be provided on the underside of the air impermeable layer. Pre-prepared foam layers and air impermeable layers may also be used.

Description

This invention relates to a flexible composite structure suitable for use as a resilient floor covering and more particularly to a fibre-reinforced floor covering comprising a layer exposed to wear and a fdam plastics layer.

Floor coverings are frequently manufactured from plasticised PVC 5 (polyvinylchloride), a reinforcement layer having a fibre structure and a foam layer disposed therebeneath. If such a floor covering is to be adequately resistant to wear, it is necessary to employ a sufficiently thick reinforcement layer. When the reinforcement layer is formed of glass fibres, a compact glass fabric of 80 to 160 g/m must be used. Moreover, the reinforcement layer has to be firmly anchored in the foam layer, or, as is usually the case between the foam layer and the layer which takes the wear, that is the PVC layer. When the reinforcement layer is formed of glass fibre, adhesion of the reinforcement layer to the layers on either side thereof generally needs to be assisted by applying to the reinforcement material before use thereof, a surface treatment agent, for example a silane or a volane (Volane is a . Trade Mark). The use of an adhesive material may also be desirable.

According to one aspect of this invention, there is provided a flexible composite structure suitable for use as a resilient floor covering which comprises an open-pore soft foam plastics layer covered on one side by a flexible - 2 41983 top, wear-receiving layer formed of thermoplastic plastics material and on the opposite side by a flexible air-impermeable layer formed of thermoplastic piastics material, with a flexible reinforcement layer formed of a material in fibre form being disposed within the foam plastics layer, within the top, wear-receiving layer or at the boundary between the foam plastics layer and the top, wearreceiving layer.

According to a second aspect of this invention there is provided a process for the production of a flexible composite structure suitable for use as a resilient floor covering according to the first aspect of this invention, the airimpermeable layer being formed of thermoplastic plastics material, which comprises applying to an endless support structure in a continuous operating procedure by single or repeated application, a thermoplastic plastics coating paste for forming a flexible air impermeable layer, and by single or repeated application a foamed or foamable paste for forming an open-pore soft foam plastics layer, and before gelling of the pastes has gone to completion, or in a separate subsequent operating step, applying to the material thus produced a top, flexible wear-receiving layer either as a preformed thermoplastic plastics sheet structure or as a thermoplastic plastics paste to be gelled in situ and effecting gelling of said pastes subsequent 1 to the application thereof, a preformed thermoplastic plastics sheet structure, when applied to an already gelled foamable paste being applied by a lamination procedure, in which process a flexible reinforcement layer formed of a material in fibre form is incorporated in the foam layer, in the top, wear-receiving layer or between the foam layer and the top, wear-receiving layer.

The composite structure of this invention is intended to be suitable for use as a resilient floor covering, although, when it is sufficiently thin it may be used as a wall covering.

A flexible threelayer composite structure of a wear-taking layer, an open-pore foam layer and air-impermeable layer surprisingly shows a rebound elasticity and a punctiform pressure superior to many floor-covering materials even - 3 41983 if a comparatively, light fibre reinforcement is used. Because of its lightness in relation to the composite structure overall, it can be anchored in the composite «. structure without any adhesive, merely by application of pressure by rollers when forming a sandwich structure from the components of the composite structure.

The use of an air-impermeable layer, in combination with an open-pore foam layer in the manner indicated enables there to be obtained a considerable degree of improvement in the ’tread-sound-absorption of the composite structure as well as excellent resistance to loss of form.

Furthermore!, it has been established that punctiform pressure loading of the composite structure causes air displaced towards one side thereof to recede immediately after the load on the top layer has been relieved and cause the rapid restoration of the top layer. Loss of air from within the structure when subjected to a pressure loading, the air passing out of the bottom of the structure, is prevented by the air-impermeable layer. If a closed-pore foam material were to be used instead of an open-pore material as specified for use in the present invention, the composite structure meeting all the other requirements of structures according to this invention, air will be displaced through the fine cell walls when the composite structure is subject to a punctiform pressure-loading, but when the loading is removed, the air volume in the foam layer is only restored slowly or even only partially. Hence the bulk of the foam layer is only restored to a limited extent.

An additional advantage of employing the air-impermeable layer is the insulation which it imparts to the foam against the effect of moisture from a support on which the composite structure is laid. If an adhesive is used to bond the composite structure to a support surface, the migration into the foam of any adhesive or the migration of plasticiser from the foam into the adhesive is prevented. Hence, unchanged behaviour in use over a long period is assured, while the composite structure maintains its physical properties.

The top or surface layer of the composite structure preferably consists of PVC. However, it can also consist of other materials, for example polyurethane, -4.41983 polyethylene or natural or synthetic rubber.

The top or surface layer is preferably from 0.8 to 4 mm thick, and more preferably from 1 to 3 mm thick, although, in special cases, it can be as much as 6 mm thick. The top layer may have a homogeneous single layer structure, being for example a sheet coloured throughout its thickness or which is possibly patterned throughout or has a marbled pattern, or a heterogeneous, i.e. multilayer structure, comprising, for example, a patterned or embossed upper layer and a bottom unpatterned layer or a relatively thick upper layer surmounting a film, for example, a printed film, which is disposed therebeneath and is visible through the upper layer.

When the wear-receiving top layer is to be formed of PVC, patterned soft PVC sheet which may be filled is generally to be used.

The foam plastics layer preferably has a thickness of from 0.5 to 8 mm, more preferably 0.5 to 5 mm, and should be of substantially open-pore construction. The foam plastics layer can consist of a single layer or of two or more identical or different layers united together by wet-in-wet application of paste adhesives for foams and joint gelling. The density of the foam layer is preferably from 0.35 to 0.60 g/cc, more preferably 0.40 to 0.55 g/cc. The foam layer may be formed of, for example, plasticised PVC, polyurethane or polyethylene.

The air-impermeable layer can be a single ply layer or a multiply layer in which the individual plastics are bonded together. The airimpermeable layer will preferably be impervious to, for example solvents and plasticisers as well as to gases, and preferably has a thickness of from 0.05 to 0.5 mm, more preferably 0.1 to 0.3 mm.

The air-impermeable layer is preferably formed of thermoplastic plastics material, for example polyethylene or polyurethane film or may be formed from parchmentised paper. The air-impermeable layer is, however, preferably formed of a film coated with a paste, more particularly a PVC paste. - 5 41983 The air-impermeable layer and foam layer are preferably prepared directly one after the other from pastes, as will be described hereinafter.

In special cases, a foam layer can be provided on the underside of the air-impermeable layer so that the latter lies between two foamed layers or another foamed, springy or insulating layer can be arranged beneath the foam layer, as a result of which the application of a floor finish (particularly Estrich plaster) can possibly be avoided.

The reinforcement layer can be formed from glass fibres or filaments made up in the form of woven or non-woven fabrics or possibly by laying down intersecting bundles of fibres.

Light fibre reinforcements having an area density preferably of 20 to 2 7 g/m and more preferably 20 to 50 g/m can be used and are, surprisingly, sufficient. Nevertheless, however, reinforcements having a density of from 70 2 to 160 g/m can be used when producing a floor covering likely to be subjected to heavy punctiform loading, for example, in sports arenas, workshops or stables.

The reinforcement layer is preferably applied at the boundary between the foam layer and top or wear-receiving layer. However, equally good results are obtained if the reinforcement layer is introduced into a still wet foamable layer from which the foam layer is to be’produced or is arranged between two already formed foam layers or between two layers which form the top layer, preferably one of the two respective contacting layers still being wet and ungelled. In each of the aforesaid cases, the reinforcement layer becomes bonded to the material on either side thereof when pressure is applied. However, a bonding agent can be applied td the reinforcement material to enhance the anchoring of the reinforcement layer in the composite structure.

Bonding agents which can be employed in the production of composite layers embodying this invention include, in particular, pastes containing copolymers of vinyl chloride with from 3 to 25% by weight based on the starting monomers, preferably 5 to 20% by weight, of vinyl acetate; the pastes generally contain a plasticiser. - 6 41983 Irrespective of whether or not a bonding agent is used, the reinforcement layer, even when comparatively light, acts as a distributor plate, and distributes forces which are acting on the top layer uniformly over a larger surface of the foam layer disposed therebeneath, which latter layer in its turn, with the assistance of the air-impermeable layer, causes a rapid restoration of the thickness of the structure.

When producing composite structures according to this invention, it is immaterial whether one uses (a) top or wear-receiving layers which are produced by laying down a plastics layer in a lamination procedure or by the paste-coating method, (b) pre-prepared foam layers or foam layers which are produced in situ from foamed or foamable pastes and (c) pre-prepared airimpermeable layers or air-impermeable layers which are formed from wet compositions in situ. However, the use of the second alternatives in cases (b) and (c) is preferable and these alternatives are used in the process forming the second aspect of this invention. It is preferred that the foam and air-impermeable layers are formed in situ from pastes in directly succeeding operational steps in which a thick paste for forming the air-impermeable layer is laid down followed, wet-in-wet, by one or more layers or coatings of like or different layers of foamed or foamable pastes, the applied coatings'preferably being simultaneously gelled and hence providing structures in which the layers which form are bonded together.

The afroesaid preferred procedure for production of a composite structure embodying this invention can be carried out with a Revers roll coating or a corresponding apparatus for applying the various pastes. Generally, endless steel bands or release paper are used as continuous supports. It is also possible to provide a preformed air-impermeable film which can serve at the same time as a support for further layers to be provided thereon. The fibre reinforcement, generally taking the form of strips of woven fabric of suitable width, can be allowed to run on the same apparatus and can be preferably laid on or pressed onto the still wet layer or coating previously laid. - 7 419 8 3 Gelling of pastes employed in the process of this invention is generally carried out simultaneously after applying last, or possibly after each individual paste layer has been applied. A gelling temperature of from 170 to 250°C can be used, heating usually being carried out in a tunnel, for example, with infra-red heating.

The product thus produced on a coating machine and still not yet provided with a top or surface layer can be stored and despatched as an intermediate product.

The application of preformed top layer can be effected by a lamination operation, for example, at temperatures of from 100 to 15O°C and using a relatively small roll pressure of from 2 to 3 atm. When the top layer is formed from a coating paste in one or more stages, it can be applied in a continuation of the paste applying procedure indicated hereinbefore.

In the laminating operation, it is preferred to use a bonding ageht, especially when the reinforcement layer constitutes the uppermost layer of the already formed structure and is to be bonded to the top layer. When using o relatively heavy reinforcement layers (over about 70 g/m ) the use of a bonding agent is advisable. The use of a bonding agent is also desirable when producing relatively thick composite structures. However, the preferred light reinforcement layers do not require the use of a bonding agent, especially when the reinforcement layer is introduced into a still wet foam layer or top layer being applied in the form of a paste. Furthermore, the use of a bonding agent is generally.unnecessary when the top layer or a lowermost top layer of a plurality of such layers is thin.

The coating pastes employed in the process of this invention can be formed in conventional manner from synthetic plastics, plasticisers, pigments and other components.

When forming a foam-forming paste, it is preferably mechanically gasified, air in finely distributed form being introduced and mixed into the paste in, for example, a Euromatic or Oakes v · · Trade Mark) mixer. It is, - 8 41983 however, also possible to use blowing agents with low decomposition temperatures of from 80 to 120°C, for example the product Porofor D 33 (Porofor is a Registered Trade Mark).

The products of this invention, particularly when prepared by one of 5 the aforesaid preferred procedures can be produced continuously and inexpensively and are of high quality. The degree of improvement in the treading soundabsorption obtained can be measured according to DIN 52 210, the change in dimensions obtained after 6 hours storage at 80°C can be measured according to DIN 51 692 and the residual indentation obtained can be measured according to DIN 51 955. These methods were employed to measure the parameters indicated in the Examples which follow.

For a better understanding of this invention and to show how the same can be carried into effect, reference will now be made, by way of example only, to the accompanying drawing which is a cross-section through a floor covering embodying this invention.

Referring to the drawing, disposed beneath a top layer 1 is an openpore foam layer 3. A fibre reinforcement 2 is disposed at the boundary of the latter layers 1 and 3 and a sealing layer 4 constitutes a bottom layer of composite structure forming the floor covering.

The following Examples illustrate this invention.

EXAMPLE 1.

For forming an air-impermeable layer, a PVC paste was prepared in accordance with the following specification: parts by weight of E-PVC with a K value 70 ,.c 33 parts by weight of di octyl phthalate parts by weight of epoxidised soya bean oil parts by weight of chalk part by weight of colouring agent 0.5 parts by weight of tin stabiliser - 9 41983 The paste was applied using a Revers roll coater in a quantity of 300 g/n/ to a steel sheet.

In order to form a foam plastics layer, a mechanically gasified PVC foam paste was applied by means of doctor blades in a thickness of 3 mm directly to the wet paste coating and yielded a foam with a density of 0.4 g/cc. In the production of the foam paste, air was mixed into a paste being produced in a Euromatic mixture from a mixture of the following constituents. 250 parts by weight of E-PVC value 70, containing emulsifier 100 parts by weight of butyl benzylphthalate parts by weight of dioctyl phthalate 100 parts by weight of chalk Before the foam paste layer had gelled, a 33 g/ιιι glass fibre fabric ( was run through and allowed to remain ih the foam paste so that as the paste gelled, it set around the fabric.

The two coatings disposed one above the other were simultaneously gelled at 190°C in a gelling duct and adhered to each other as they gelled.

They were then lifted off the steel belt.

The supported and reinforced foam plastics web thus produced was then coated on the fabric side with an adhesive paste, consisting of: parts, by weight of a copolymer, consisting of 10%. by weight vinyl acetate and 90% by weight vinyl chloride, with a K value 65 parts by weight of butyl benzyl phthalate parts by weight of diocyl phthalate 2 in a quantity of 150 g/m . A top or wear-receiving layer having a thickness of 2 mm and having a homogeneous structure having been produced by an extrusion melt procedure was then applied to the adhesive coating by a calendering method using infra-red radiation to raise the temperature of the material being calendered to 130°C. - 10 41883 The composite structure thus formed had a thickness of 5 mm, a degree of improvement in sound-absorption under a treading pressure of 20 dB, a change in dimensions of 0.1 % and a residual indentation after loading and unloading for 24 hours of 0.11 mm.

EXAMPLE 2.

A structure consisting of an air-impermeable layer, a foam layer and a glass fibre support was produced in the same manner as in Example 1, but for the differences that a coating equipped with a continuous steel belt was used and that the air-impermeable layer had a thickness of 0.2 mm, the foam material had a 2 thickness of 2.5 mm and the glass fibre had a weight per unit area of 30 g/m .

No bonding paste was used.

The structure thus obtained when fully gelled was applied to a top layer built up of two coatings and having a total thickness of 1.2 mm. This composite top layer had also been produced on a steel belt. The components of the heterogeneous top layer had the following compositions: 1st component-application 1000 g/m parts by weight of E-PVC, K value 70 parts by weight of dioctyl phthalate part by weight of epoxidised soya bean oil parts by weight of chalk 0.5 parts by weight of stabiliser parts by weight of colouring agent 2nd component (surface layer)-application 1000 g/m parts by weight of E-PVC, K value 70 parts by weight of butyl benzylphthalate part by weight of epoxidised soya bean oil parts by weight of chalk parts by weight of colouring agent part by weight of stabiliser Gelling temperature: 250°C. - 11 EXAMPLE 3.

The procedure of Example 2 was repeated with the difference that, in the production of the composite structure, the top or surface layer was first produced in a separate operational step on a coater with a steel belt.

The top'layer thus prepared was covered in a similar manner to that ». carried out in Example 1, with the initial product consisting of air-impermeable layer, foam plastics layer and glass fibre fabric, employing the copolymer adhesive paste used in Example 1, and the top layer was subsequently embossed.

The composite structure thus produced had a thickness of 4 mm, showed a degree of tread sound improvement of 20 dB, a change in dimensions of 0,03% and a residual indentation Of 0.12 Iran after being loaded and unloaded for 24 hours.

. EXAMPLE 4.

A foam plastics sheet produced in a manner similar to that described in Example 1 but with a thickness of 1.5 mm, and an air-impermeable layer with a thickness of 0.2 mm were superposed and completely gelled after incorporation of the glass fibre fabric, as in Example 1. A 0.45 mm thick PVC coating, which was produced from a paste having a composition similarto the first paste composition of Example 2, was then applied to the foam side of the composite structure thus produced and was then covered with a 0.15 mm thick soft PVC sheet printed on the back and the composite structure thus obtained was embossed.

The composite structure thus obtained had a thickness of 2.3 mm, a degree of improvement in the sound absorption of 17 dB, a change in dimensions of 0.04% and a residual indentation after loading and unloading for 24 hours of 0.05 mm.

Claims (30)

1. A flexible composite structure suitable for use as a resilient floor covering which comprises an open-pore soft foam plastics layer covered on one side by a flexible top, wear-receiving layer formed of thermoplastic plastics material and on the opposite side by a flexible air-impermeable layer with a flexible reinforcement layer formed of a material in fibre form being disposed within the foam plastics layer, within the top, wear-receiving layer or at the boundary between the foam plastics layer and the top, wear-receiving layer.

2. A composite structure as claimed in Claim 1, wherein the top, wearreceiving layer is a polyvinylchloride layer.

3. A composite structure as claimed in Claim 1 or 2, wherein the top, wear-receiving layer has a thickness of from 0.8 to 5 mm.

4. A composite structure as claimed in Claim 3, wherein the top, wearreceiving layer has a thickness of from 1 to 3 mm.

5. A composite structure as claimed in any one of the preceding claims, in which the top, wear-receiving layer has a multi-layer structure, comprising a patterned or embossed surface layer and an unpatterned layer thereunder.

6. A composite structure as claimed in any one of Claims 1 to 4, in which the top, wear-receiving layer has a multi-layer structure, comprising a relatively thick surface layer surmounting a film disposed therebeneath and visible therethrough.

7. A composite structure as claimed in any one of the preceding claims, wherein the foam plastics layer has a thickness of from 0.5 to 8 mm.

8. A composite structure as claimed in any one of the preceding claims, wherein the foam plastics layer has a foam density of from 0.35 to 0.60 g/cc.

9. A composite structure as claimed in any one of the preceding claims, wherein the foam plastics layer has a foam density of from 0.40 to 0.55 g/cc.

10. A composite structure as claimed in any one of the preceding claims, wherein the air-impermeable layer is formed of parchmentised paper. - 13 41983 Π. A composite structure as claimed in any one of Claims 1 to 9, wherein the air-impermeable layer is formed of thermoplastic plastics material.

11. 12. A composite structure as claimed in Claim 11, wherein the airimpermeable layer is formed from a film coated with a synthetic plastics paste.

12. 13. A composite structure as claimed in Claim 12, wherein the film is coated with polyvinylchloride paste.

13. 14. A composite structure as claimed in any one of the preceding claims, wherein the air-impermeable layer has a thickness of from 0.05 to 0.5 mm.

14. 15. A composite structure as claimed in Claim 14, wherein the airimpermeable layer has a thickness of from 0.1 to 0.3 mm.

15. 16. A composite structure as claimed in any one of the preceding claims, whereih the reinforcement layer is formed of glassfibre material.

16. 17. A composite structure as claimed in any one of the preceding claims, wherein the reinforcement layer has a weight of from 20 to 160 g/m .

17. 18. A composite structure as claimed in any one of the preceding claims, wherein the reinforcement layer has a weight of from 20 to 50 g/m .

18. 19. A composite structure as claimed in any one of the preceding claims, wherein the reinforcement layer is disposed at the.boundary between the top, wearreceiving layer and the foam plastics layer, with a coating of a bonding paste being disposed on the reinforcement layer.

19. 20. A flexible composite structure as claimed in Claim 1, substantially as described in any one of the foregoing Examples.

20. 21. A process for the production of a flexible composite structure suitable for use as a resilient floor covering, as claimed in Claim 11, which comprises applying to an endless support structure in a continuous operating procedure by single or repeated application, a thermoplastic plastics coating paste for forming a flexible air-impermeable layer, and by a single or repeated application a foamed or foamable paste for forming an open-pore soft foam plastics layer, and before gelling of the pastes has gone to completion, or in a separate subsequent operating step, applying to the material thus produced a top, flexible - 14 41983 wear-receiving layer either as a preformed thermoplastic plastics sheet structure or as a thermoplastic plastics paste to be gelled in situ and effecting gelling of said pastes subsequent to application thereof, a preformed thermoplastic plastics sheet structure, when applied to an already gelled foamable paste being applied by a lamination procedure, in which process a flexible reinforcement layer formed of a material in fibre form is incorporated in the foam layer, in the top, wearreceiving layer or between the foam layer and the top, wear-receiving layer.

21. 22. A process as claimed in Claim 21, wherein the paste coating(s) for forming the air-impermeable layer and the paste coating(s) for forming the foam layer are simultaneously gelled by application of heat.

22. 23. A process as claimed in Claim 21 or 22, wherein the reinforcement layer is applied to a foamable paste coating prior to gelling thereof.

23. 24. A modification of the process claimed in any one of Claims 21 to 23, in which the endless support is constituted by an endless preformed sealing layer to which is applied the foam forming paste.

24. 25. A process as claimed in any one of Claims 21 to 24, in which a bonding paste is applied to the reinforcement layer to be incorporated into the composite structure.

25. 26. A process as claimed in any one of Claims 21 to 25, in which a top, wear-receiving layer is applied by a lamination procedure to a gelled foam layer with interposition of a bonding paste layer.

26. 27. A process as claimed in Claim 25 or 26, wherein the bonding paste is based on a copolymer of vinyl chloride and vinyl acetate, the copolymer containing from 3 to 25% by weight of vinyl acetate units based on the starting monomers.

27. 28. A process for the production of a flexible composite structure as claimed in Claim 21, substantially as described in any one of the foregoing Examples.

28. 29. A flexible composite structure, whenever produced by the process claimed in any one of Claims 21 to 28. - 15 41983

29.

30. A flexible composite structure, substantially as hereinbefore described with reference to, and as shown in, the accompanying drawing.