GB2576971A

GB2576971A - Underlay

Info

Publication number: GB2576971A
Application number: GB1909817.7A
Authority: GB
Inventors: Robson Paul
Original assignee: Instafibre Ltd
Current assignee: Instafibre Ltd
Priority date: 2018-09-09
Filing date: 2019-07-09
Publication date: 2020-03-11
Anticipated expiration: 2039-07-09
Also published as: GB201811242D0; WO2020012148A1; GB2576971B; GB201909817D0

Abstract

A flexible underlay providing thermal and/or acoustic insulation and/or cushioning. The underlay having a first exposed surface on one side and a second exposed surface opposite the first. The underlay is provided with a magnetic or magnetisable material either within the body of the underlay adjacent at least one expose surface or as a coating layer on at least one surface. The magnetic material may be paramagnetic or non-magnetised ferromagnetic material. When the material is a non0magnetised ferromagnetic coating north and south magnetic poles may be introduced in the material after application. Also included are claims to a flooring system comprising the underlay and a floor covering, the covering having a corresponding addition of material/coating on a lower surface such that magnetic attraction holds the covering and underlay together. Further included are methods for forming underlays comprising magnetic particles in a crumb rubber overlay or a coating material on one surface of a crumb underlay, both of which may be formed with or without a scrim layer.

Description

(54) Title of the Invention: Underlay Abstract Title: Underlay (57) A flexible underlay providing thermal and/or acoustic insulation and/or cushioning. The underlay having a first exposed surface on one side and a second exposed surface opposite the first. The underlay is provided with a magnetic or magnetisable material either within the body of the underlay adjacent at least one expose surface or as a coating layer on at least one surface. The magnetic material may be paramagnetic or non-magnetised ferromagnetic material. When the material is a nonOmagnetised ferromagnetic coating north and south magnetic poles may be introduced in the material after application. Also included are claims to a flooring system comprising the underlay and a floor covering, the covering having a corresponding addition of material/coating on a lower surface such that magnetic attraction holds the covering and underlay together. Further included are methods for forming underlays comprising magnetic particles in a crumb rubber overlay or a coating material on one surface of a crumb underlay, both of which may be formed with or without a scrim layer.

At least one drawing originally filed was informal and the print reproduced here is taken from a later filed formal copy.

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FIG. 1

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FIG. 2

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FIG. 3

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FIG. 5

UNDERLAY

This disclosure relates to underlays, for example for floor coverings, and more particularly, although not necessarily exclusively to crumb-rubber underlays.

Crumb-rubber underlays in which the crumbs are bonded to each other and to a supporting scrim layer on at least one side have been used as general purpose flooring underlays for over 40 years as they have a number of inherent properties that make them especially useful for the higher end of the market, namely:

• relatively high mass per unit volume (density), which produces a material that has a high “flop-weight”;

• highly efficient acoustic insulation properties as a consequence of its relatively high density;

• the crumb-rubber particles, which make up 80-90% of the volume of the product, consist of vulcanised rubber and therefore cannot collapse over time;

• an open-cell structure resulting from bonding of the rubber granules to one another during manufacture of the product using a synthetic rubber binder;

• during compression of the product, the vulcanised rubber granules compress and then immediately rebound to their original shape once the pressure is released, so that the product always returns to its original shape and thickness after compression, regardless of the extent or duration of that compression;

• as compared with a solid rubber sheet, the flexible open-cell structure allows the product to be compressed relatively easily when subjected to a point load, and yet provides a firm, non-collapsing surface when subject to a distributed load;

• the open-cell structure allows air to flow freely through the material, making the product more “breathable” and more hygienic at the microbial level;

• the open-cell structure allows heat transfer through air circulation, but still has relatively good thermal insulation properties;

• the product can be flooded and then dried in situ without altering performance or causing odours; and • exposed rubber granules form a surface that results in enhanced grip on most surfaces with which it comes into contact.

Despite these known properties and this long period of use, it appears that it was not until 2008 that any proposal was made for a crumb-rubber underlay with a scrim material layer on at least one side to be provided with a coating of a pressure sensitive adhesive.

Instead, conventional rubber-crumb underlays were typically unrolled from a supply of the underlay over a sub-floor, typically of concrete, in a private residence, hotel or other public building requiring flooring, and its edges cut to shape to fit the room. Edges of the underlay would be fitted to edge holding means, such as gripper rods, fastened to the subfloor, and the surface of the underlay would then be coated with a suitable adhesive applied using a brush or roller before the floor covering, consisting of carpet, such as woven, tufted or needlepunch broadloom carpet, carpet tiles such as tufted or needlepoint tiles, vinyl sheeting, linoleum, luxury vinyl flooring tiles, or wooden flooring such as woodblock, tongue-and-groove, wooden strip flooring or wood laminate, laid on to and subsequently held in place by the adhesive.

ZA2008/04310 of Rubber Lay (Pty) Ltd proposed an alternative arrangement in which the adhesive was applied as a coating of a pressure sensitive adhesive to the underlay during manufacture. The adhesive was protected by a silicone release paper that could be removed by a floor-covering installer to expose the adhesive to allow the underside of the floor covering to be adhered to the exposed adhesive of the underlay.

It appears that this underlay may not have been a commercial success since Rubber Lay (Pty) Ltd went into voluntary liquidation in February 2009, only small sample volumes of their crumb-rubber underlay product having ever been produced. Applicant’s experimental work, which led to their British Patents Nos: GB2482239 and GB2482240, suggested that the adhesive employed by Rubber Lay (Pty) Ltd in their practical embodiment was simply too fierce to allow for any error or adjustment during laying of the flooring.

Subsequently Applicant has developed a range of crumb-rubber underlays employing the teachings of their above mentioned British Patents, and sold under their InstaLay® Trademark, which are suitable for a employment with a range of different floor coverings, whether for permanent application or for application where the flooring may need to be taken up again at a later date.

Applicant has also developed a range of crumb-rubber underlays that do not require a scrim or other strengthening layer (See: W02016/059360 and WO2016/059361).

The feature common to all crumb-rubber underlays to date, is that an adhesive is employed either during the laying of the underlay and floor covering or by providing a pressure sensitive adhesive already on the surface of the underlay during manufacture with a release sheet protecting the adhesive until adhesion is required when the floor covering is laid over the underlay.

The present disclosure adopts an entirely different approach, which makes the application of adhesive or the pre-coating of the underlay with adhesive during manufacture unnecessary. Working with adhesives is potentially hazardous.

Applicant is aware of two prior proposals for adhesive-free flooring application, but neither can employ underlays.

Referring to Fig. 1, Havwoods International have proposed a system for raised access wooden flooring under their Magna® Registered Trademark, in which wooden tongue-and groove strips 1 are laid over a raised floor made of steel sections 2 mounted above a subfloor 3 by support struts 4. Each wooden strip is provided with magnetic elements 5 so that the strips are held in place by magnetic attraction between the strips and the steel sections, but can be removed at will.

In an alternative proposal, the IOBAC® (Registered Trademark of lobac Ltd of St Peter Port, Guernsey, Channel Islands) system was developed by a partnership between international chemicals manufacturer 3M, Interface - the world’s largest carpet tile manufacturer, and Karndean Design Flooring, a leading supplier of luxury vinyl floor tiles. Referring to Fig. 2, in use of this system, a paramagnetic epoxy resin coating 6 is applied directly to the subfloor, smoothed off and allowed to dry or cure in situ, which generally takes an hour. To complete the laying of the floor covering after an hour’s delay, a magnetic floor covering 7 manufactured by Interface or Karndean with a magnetic layer 8 is then dry laid on to the paramagnetic layer 6. Floor coverings can be removed or replaced at will.

In use of this system, the magnetic floor coverings are necessarily laid directly on to the dried metallised paramagnetic epoxy coating. As a result this system is only suitable where a relatively hard foot feel is acceptable, and acoustic and thermal insulation is not important, as for example in a cafe or supermarket. The luxury cushioned feel and acoustic and thermal insulation that results from an underlay such as a crumb-rubber underlay between the subfloor and the floor covering, which is required in domestic residences and in public buildings such as hotels is not feasible with either of the Havwoods International or lobac Ltd proposals for adhesive-free flooring.

In accordance with a first aspect of the present disclosure, there is provided a flexible underlay adapted to provide cushioning and/or thermal and/or acoustic insulation when laid between a subfloor and a floor covering, the underlay having a first exposed surface on one side and a second exposed surface on an opposed side, the underlay being provided during manufacture with magnetic or magnetisable material within the body of the underlay adjacent at least one of said exposed surfaces or with a flexible coating comprising magnetic or magnetisable material on at least part of one said exposed surface.

In one embodiment, the magnetic or magnetisable material comprises a paramagnetic material or particles of a non-magnetised ferromagnetic material. In the latter case, the underlay may be provided during manufacture with a flexible coating metallised with particles of a non-magnetised ferromagnetic material. Optionally, an array of alternative magnetic north and magnetic south poles may be induced in the otherwise non-magnetised ferromagnetic material after application of the coating to the one said exposed surface.

In a second aspect of the present disclosure, we provide a floor laying system in which a first surface of a floor covering is laid on an exposed surface of an underlay directly laid on a subfloor, without use of any adhesive to hold the floor covering in place on the underlay; one of the floor covering and the underlay being provided with paramagnetic or metallised material, namely particles of a nonmagnetised ferromagnetic material, within the body of the floor covering adjacent said first surface or coating said first surface, or within the body of the underlay adjacent said exposed surface or coating said exposed surface; and the other of the floor covering at said first surface and the underlay at said exposed surface comprising a flexible magnetic surface with an array of alternative magnetic north and magnetic south poles induced therein.

In a third alternative aspect of this disclosure, there is provided a method of manufacturing a crumb-rubber underlay, the method comprising the steps of: bonding crumbs of rubber to each other to form a crumb-rubber layer and to a supporting scrim layer; and applying a flexible coating to at least part of the exposed surface of the scrim material or of the crumb-rubber layer, the material of the coating comprising particles of a paramagnetic or ferromagnetic material in a plastics binder.

In a fourth alternative aspect of this disclosure, there is provided a method of manufacturing a crumb-rubber underlay with magnetic or magnetisable properties, the method comprising the steps of: bonding crumbs of rubber to each other to form a crumb-rubber layer and to a supporting scrim layer; in which particles of a paramagnetic or ferromagnetic material are incorporated among the crumbs of rubber prior to said bonding step.

In a fifth alternative aspect of this disclosure, we provide a method of manufacturing a crumb-rubber underlay with magnetic or magnetisable properties, the method comprising the steps of: bonding crumbs of rubber to each other to form a crumb-rubber layer without any scrim or other supporting layer; and applying a flexible coating to at least part of the exposed surface of the crumb-rubber, the material of the coating comprising particles of a paramagnetic or ferromagnetic material in a plastics binder.

According to a sixth and yet further aspect of this disclosure, there is provided a method of manufacturing a crumb-rubber underlay with magnetic or magnetisable properties, the method comprising the step of: bonding crumbs of rubber to each other to form a crumb-rubber layer without any scrim or other supporting layer; particles of a paramagnetic or ferromagnetic material being incorporated among the crumbs of rubber prior to said bonding step.

In embodiments in which the flexible coating is applied to a crumb-rubber or scrim layer, the plastics binder for the flexible coating is preferably a urethane binder.

In one embodiment, the coating material comprises particles of a highcoercivity ferromagnetic compound, preferably ferric oxide, in a plastics binder and wherein the coated underlay is magnetized by passing it partially around a freely rotatable cylinder with an array of permanent magnets arranged with alternating magnets having oppositely disposed magnetic poles, thereby to induce a corresponding arrangement of alternating magnetic north and magnetic south poles in the coated material on the underlay.

Reference may now be made to the accompanying drawings, by way of example only, in which:

Fig. 1 is a partial perspective view illustrating one prior art arrangement;

Fig. 2 is a partial perspective view illustrating another prior art arrangement;

Fig. 3 shows a somewhat schematic perspective side elevation of a portion of a first embodiment of underlay in accordance with the teachings of the present disclosure;

Fig. 4 shows a cylinder formed of permanent magnets for inducing a pattern of magnetic poles in one embodiment of our underlay; and

Fig. 5 shows a somewhat schematic sectional view through an alternative embodiment.

Referring to Fig. 3, a generally sheet form underlay 10 includes a crumbrubber layer 12 with scrim material 14 bonded to a first surface of the crumb-rubber layer. It will be understood that, in practice, the individual crumbs of the crumbrubber layer will not be uniform in size or exclusively oval in section. Crumb rubber underlays bonded to scrim are well known, as are their manufacturing techniques, and so only a brief description is deemed necessary here. The scrim is bonded to the rubber crumbs and the crumbs to each other at the same time. The “wet” crumb rubber compound (that is: including a synthetic rubber latex or natural rubber binder) is laid onto the scrim prior to moving under a doctor blade which skims the wet compound to the correct thickness. The scrim then carries the wet compound through the curing oven and, as the binder sets, it binds the crumb rubber particles to one another and, at the same time, to the scrim which is carrying the compound through the curing stenter oven. The thickness of the rubber layer is suitably between 2mm and 15mm. The rubber layer may be flat with a uniform thickness across both width and length of the underlay, as shown in Fig. 3, or may be undulating with a corrugated profile on its second side.

The scrim material may be chosen from different weights of non-woven polypropylene, woven polypropylene, woven poly-jute, namely a combination of woven polypropylene and jute, jute, fiberglass reinforced cellulose, woven fiberglass, non-woven fiberglass, woven polyester, non-woven polyester, or of stitch bonded crepe paper, but is typically a 30g/m² or 60g/m² non-woven polypropylene. For practical manufacturing considerations, we prefer the 60g/m non-woven polypropylene.

A uniform magnetic or magnetisable flexible coating 16 is applied to the surface of the scrim material 14. The coating 16 could equally well be applied in a pattern of spots or as uniform bands or overlapping swirl-spray strands across the surface of scrim material 14. Alternatively, the coating 16 could be applied to the rubber surface.

Magnetisable coatings include those comprising a ferromagnetic material, such as iron filings, or ferrite, in a plastics binder, and are referred to herein as metallised coatings not having magnetic poles.

The coating may comprise particles of a high coercivity ferromagnetic compound such as ferric oxide, in a suitable plastics binder. In embodiments in which the coating is applied to the crumb-rubber material directly, the plastics binder is preferably a urethane binder since this binds well with rubber materials. Suitable coatings are well known and widely available for the manufacture of flexible fridge magnets, and so a full description of detailed Examples is deemed unnecessary. In the present case, a lower thickness and coat weight than employed for fridge magnets produces satisfactory results because of the extended surfaces across which magnetic attraction will apply between the floor covering and the underlay, while ensuring that the flexibility of the underlay is maintained.

Typical coating compositions employed in our coatings may employ quick drying synthetic resins and coating compositions used in a typical paint. Examples include alkyd resins, butylated amino aldehyde resins, phenolic resins, vinyl chloride resins, vinyl acetate resins, epoxy resins, acrylic resins, and urethane resins, all of which can be used provide that the dried coating remains flexible. Good results are obtained with a vinyl chloride/vinyl acetate co-polymer.

The magnetic floor coverings available from Havwoods International for use in their Magna flooring or from Interface and from Karndean Design Flooring for use in the lobac system can be directly applied to an underlay of the kind described above provided with a simple paramagnetic or metallised coating not having magnetic poles.

In an alternative arrangement, our system may be used with floor coverings that are not themselves magnetic, provided that they have a simple paramagnetic or metallised coating, as described above. In such an arrangement, the underlay must be provided with a magnetic coating. The coating 16 applied to the underlay during manufacture preferably comprises a high coercivity ferromagnetic compound, preferably feme oxide, in a plastics binder, and an array of alternative magnetic north poles and magnetic south poles are induced in the coating in a manner similar to the arrays induced in the surface of a flexible fridge magnet by passing the coated underlay partially around a freely rotatable cylinder 18, as illustrated in Fig. 4, in which a stack of cylindrical magnets 20 are arranged with their poles alternating, as shown. As a result the coated underlay has an array of induced alternating magnetic poles and is strongly attracted to a closely adjacent paramagnetic or metallised coating on the floor covering but exhibits essentially no net magnetic effect at greater distances. As a result, the magnetically laid flooring will not interfere with mobile phone transmissions.

In a completed installation, the crumb-rubber underlay will typically provide a cushioning effect, as well as acoustic and thermal insulation, but the floor covering can readily be taken up and replaced.

Although the detailed description hereinabove relates to a crumb-rubber underlay with a scrim layer on one side, it will readily be appreciated that a flexible magnetic or magnetisable coating can equally well be applied to at least part of one exposed surface of an embodiment of crumb-rubber underlay that has no scrim or other supporting layer, or, indeed, to any other form of underlay that has no adhesive layer present.

Fig. 5 shows an alternative arrangement, which, as shown, is scrimless. In the arrangement of Fig. 5, there is no applied coating. Instead, particles 22 of a paramagnetic or ferromagnetic material are distributed within the crumb-rubber layer

12. This can readily be achieved by adding a suitable such material, for example, fine particles of iron or steel, iron filings or ferrite to the “wet” crumb-rubber compound prior to the bonding step.

Although shown in a scrimless version in Fig. 5, there is no necessity for the magnetic or magnetisable underlay to be scrimless. Where preferred, or for additional strength, the bonding step with added particles 22, may bond the individual crumbs of rubber to each other and to a suitable scrim layer 14.

Claims

1. A flexible underlay adapted to provide cushioning and/or thermal and/or acoustic insulation when laid between a subfloor and a floor covering, the underlay having a first exposed surface on one side and a second exposed surface on an opposed side, the underlay being provided during manufacture with magnetic or magnetisable material within the body of the underlay adjacent at least one of said exposed surfaces or with a flexible coating comprising magnetic or magnetisable material on at least part of one said exposed surface.

2. An underlay according to Claim 1, wherein the magnetic or magnetisable material comprises a paramagnetic material, or particles of a non-magnetised ferromagnetic material.

3. An underlay according to Claim 2, wherein the underlay is provided during manufacture with a flexible coating metallised with particles of a non-magnetised ferromagnetic material on one of the said exposed surfaces, optionally with an array of alternative magnetic north and magnetic south poles induced in the otherwise nonmagnetised ferromagnetic material after application of the coating to the one said exposed surface.

4. A floor laying system in which a first surface of a floor covering is laid on an exposed surface of an underlay directly laid on a subfloor, without use of any adhesive to hold the floor covering in place on the underlay; one of the floor covering and the underlay being provided with paramagnetic or metallised material, namely particles of a non-magnetised ferromagnetic material, within the body of the floor covering adjacent said first surface or coating said first surface, or within the body of the underlay adjacent said exposed surface or coating said exposed surface; and the other of the floor covering at said first surface and the underlay at said exposed surface comprising a flexible magnetic surface with an array of alternative magnetic north and magnetic south poles induced therein.

5. A method of manufacturing a crumb-rubber underlay, the method comprising the steps of: bonding crumbs of rubber to each other to form a crumb-rubber layer and to a supporting scrim layer; and applying a flexible coating to at least part of the exposed surface of the scrim material or of the crumb-rubber layer, the material of the coating comprising particles of a paramagnetic or ferromagnetic material in a plastics binder.

6. A method of manufacturing a crumb-rubber underlay with magnetic or magnetisable properties, the method comprising the steps of: bonding crumbs of rubber to each other to form a crumb-rubber layer and to a supporting scrim layer; in which particles of a paramagnetic or ferromagnetic material are incorporated among the crumbs of rubber prior to said bonding step.

7. A method of manufacturing a crumb-rubber underlay with magnetic or magnetisable properties, the method comprising the steps of: bonding crumbs of rubber to each other to form a crumb-rubber layer without any scrim or other supporting layer; and applying a flexible coating to at least part of the exposed surface of the crumb-rubber, the material of the coating comprising particles of a paramagnetic or ferromagnetic material in a plastics binder.

8. A method of manufacturing a crumb-rubber underlay with magnetic or magnetisable properties, the method comprising the step of: bonding crumbs of rubber to each other to form a crumb-rubber layer without any scrim or other supporting layer; particles of a paramagnetic or ferromagnetic material being incorporated among the crumbs of rubber prior to said bonding step.

9. A method according to Claim 5 or Claim 7, wherein the plastics binder for the flexible coating is a urethane binder.

10. A method according to Claim 5 or Claim 7, wherein the coating material comprises particles of a high-coercivity ferromagnetic compound, preferably ferric oxide, in a plastics binder, and wherein the coated underlay is magnetized by passing it partially around a freely rotatable cylinder with an array of permanent magnets arranged with alternating magnets having oppositely disposed magnetic poles, thereby to induce a corresponding arrangement of alternating magnetic north and magnetic south poles in the coated material on the underlay.

Intellectual

Property

Office

Application No: GB1909817.7

Examiner: Dr Peter Aspinall