GB2389526A

GB2389526A - Mat

Info

Publication number: GB2389526A
Application number: GB0308398A
Authority: GB
Inventors: Peter Charles Brazier; Thomas Albert Patrick Brock; Robert C Kerr; Bhawan Patel; Flemming Boejstrup; Patrick Morel
Original assignee: Milliken Industrials Ltd
Current assignee: Milliken Industrials Ltd
Priority date: 2002-06-13
Filing date: 2003-04-11
Publication date: 2003-12-17
Anticipated expiration: 2023-04-11
Also published as: GB2389526B; GB0308398D0

Abstract

A mat with a textile surface and an elastomer backing layer that includes elastomer crumbs 6 and a binder. The elastomer backing layer includes voids between the elastomer crumbs for increased flexibility.

Description

MAT Technical Fleld The present invention relates to a mat having a

textile surface and an elastomer backing In particular, but not exclusively, the Invention relates to a floor mat The Invention also relates to other mats and mat-lke products, including for example table mats and bar runners.

Background to the Invention

10 Floor mats having a textile surface and a rubber backing are very well known and have been manufactured for many years Typically, such mats Include a tufted pile textile surface. for example of nylon, cotton, polypropylene or a mixture of such flares, which Is bonded to a rubber backing sheet. Such mats are usually made by bonding the textile surface layer to a sheet of uncured rubber in a heated press The heat from the press vulcanses (cures) the rubber and at lit the same time bonds it to the textile layer A process for manufacturing such mats Is described In EP 0 367 441 A. Such mats have very good dust control charactenshcs, are highly effective at removing dirt and moisture from the feet of pedestrians, and have a good feel and appearance. The mats are also washable, extremely durable, highly flexible and lie flat on the floor 20 Rubber backed floor mats with surfaces made of other textiles are also known. These textiles may Include knitted, woven, or non-woven fabrics (such as needle felts or spun-bonded fabrics), with or without a pile or raised nap, as well as flocked surfaces The textile surface may be bonded under pressure to a rubber backing sheet, using a process similar to that described above. Other mats and mat-like products, such as table mats and bar runners, have also been 25 made In a similar fashion One disadvantage of the mats described above Is that they tend to be rather expensive, owing to the relatively high cost of the rubber backing matenal. As a result, those mats have enjoyed only limited commercial success In certain market sectors, where a lower cost product Is required For example, in the commercial and retail market sectors, rubber backed dust control 30 mats have achieved a market penetration of only about 5% of total mat sales, the remainder of the matting sold Into this market sector being either unbacked or backed with PVC or latex However, PVC and latex backed mats do have a number of disadvantages as compared with conventional rubber backed mats In particular, PVC backed mats have poor flexibility,

especially at low temperatures, and after being unrolled such mats often do not lie flat on the floor They also have an offeror appearance and feel when compared with rubber backed mats, can become brittle with age, and can have poor resistance to movement when placed on top of carpet There are also growing environmental concerns associated with the manufacture 5 and disposal of PVC backed mats. These disadvantages have, however been tolerated in certain market sectors, owing to the lower cost of the mats Recycled rubber has been used effectively at a low cost substitute for virgin rubber In certain applications. Some examples of such applications are discussed below: EP 0135595 describes a method for manufacturing a floor covering In the form of a web, which 10 may be used as a sports surface. The web consists of a lower textile base and an upper layer of disintegrated waste rubber and/or granules of new or scrap rubber that has been mixed with a pre-polymer as a solvent-free sngle- component binder, spread on a conveyor belt, compressed and subsequently cured DE 4212757 describes a moulded component forming an elastic layer and comprising a mixture IS of granulated recycled material and binders The component has three compressed layers of uniform thickness bonded together at their Interfaces Upper and middle layers are formed by flat plates and the lower layer has hump-shaped feet separated by grooves. The Individual layers are formed In different materials with different particle sizes. The component can be used as a covering, for example for floors 70 A mat with a compression moulded rubber crumb backing and having a flock surface applied to the backing Is available under the brand name "Royal mat". The compression moulded backing Is made by mixing rubber crumb with a binder and then compressing a layer of the mixture In a mould at a high pressure while the binder bonds the crumbs together The flocked textile surface Is subsequently applied to the backing using an adhesive 25 Compression moulding produces a rubber crumb backing that has a high density and low deformability. This makes the mat heavy and Inflexible, with the result that it does not conform well to the shape of the floor beneath it. The mat does not therefore have the performance charactenstcs of a conventional rubber backed mat Rubber carpet underlay manufactured from lightly bonded crumb rubber Is also known. The 30 underlay Is however made without any significant pressure and as a result it is not sufficiently well bonded to make it durable enough for use as a mat backing Notwithstanding the aforesaid applications, recycled rubber does not have the same performance characteristics as virgin rubber In particular, it has a lower tear resistance and a higher stiffness owing to the presence of a binder material As a result, recycled rubber has not

generally been thought suitable for use as the backing material for a mat, since it has been thought to offer no significant advantages over PVC It Is therefore desirable to provide a mat that overcomes the performance shortcomings of PVC backed mats and compression moulded mats, and that avoids the relatively high cost 5 associated with conventional rubberbacked mats.

Disclosure of the Invention

According to one aspect of the present Invention there Is provided a mat with a textile surface and an elastomer backing that Includes elastomer crumbs and a binder, charactensed In that the elastomer backing Includes voids between the elastomer crumbs 10 Throughout this specification the term "crumb" has the normal meaning In the rubber Industry of

any "broken down" rubber: thus, a crumb of rubber can be any size in a range that includes powder, granules and chips The term "powder" means crumb that will pass a 2 mm mesh or crumb with a maximum dimension of 2 mm as the context requires "Granule" means crumb that will pass a 6 mm mesh or crumb with a maximum dimension of 6mm, as the context 15 requires. Granules may Include some powder but are generally larger than powder and have a weight average size that Is near to the maximum of the size specification for the granule

Chips" means crumbs that are larger than granules We have found, surpnsngly, that it Is possible to make a mat having superior performance characteristics with a backing made of elastomer crumb and a binder. In particular, we have 20 found that by carefully controlling the pressure In the production process, we can produce a mat with voids between the elastomer crumbs in the backing, which meets or exceeds the performance of mats with a PVC backing layer and exshng compression moulded mats. The mat can be produced In a single process, using relatively inexpensive materials (for example, recycled rubber from old mats), and therefore provides a high performance but low cost 25 alternative to conventional rubber-backed mats, compression moulded mats and PVC mats.

The presence of voids between the crumbs increases the flexibility of the backing, thereby compensating for the stiffening effect of the binder and providing a deformability that Is comparable to that of a conventional rubber backing. The mat Is more flexible than both compression moulded rubber backed mats and PVC backed mats, In the latter case particularly 30 at low temperatures. The tear strength of the backing is however much greater than that of granulated rubber carpet underlay, and Is adequate for most mat backings, even in unsupported border regions of the mat The backing is also extremely stable when placed on top of carpet, probably because the pile flares of the carpet are gripped In the numerous small gaps between the crumbs of the backing It Is also relatively fight and it has good fire resistance compared to 35 a conventional rubber backed mat

The elastomer Is preferably rubber, and more preferably nitrle rubber This backing material provides better performance than PVC at a cost that may be less than PVC and without the environmental concerns associated with PVC. Nitrile rubber Is a term used to describe a compounded rubber mixture of which the main polymeric content is an acrylontnle butadene; S copolymer It may also contain fillers such as carbon black, a curing system, plastcsers and other ancilary components. This backing material provides better performance than PVC at a cost that may be less than PVC and without the environmental concerns associated with PVC Advantageously, the elastomer crumb backing exhibits a deformability from at least 14% as measured by the test herein defined. Preferably the deformability is 14 to 50%, more preferably 10 14to25%.

Advantageously, the elastomer backing has a bulk density In the range 45 to 70%, preferably 55 to 70%, of the elastomer from which the crumbs are made.

Advantageously, the backmg has a density of less than 1g/cm3. The backing preferably has a density In the range 0.5 to 0 9g/cm3, more preferably 0 7 to O.9g/cm3 IS Advantageously, the backing exhibits a tear resistance strength of at least 0 8N/mm2 Preferably the tear resistance strength is about 1.5N/mm2 or higher.

The mat backing preferably has a thickness of a least 1 mm. The crumb size preferably may be within the range of about 0 8mm to about 6mm, with crumb sizes less than about 5 mm diameter being generally preferred More specifically, crumb sizes within the range of about 20 2mm to about 4mm, and preferably sizes of about 3mm or less, have been found to be particularly advantageous for use The choice of crumb size to be used, and the relative percentage of powder used, If any, depends somewhat upon the desired performance aspects -a of the mat and the desired manufacturing cost. Because use of small crumb (say, for example, powder less than about 1 mm) tends to require Increased use of binder and thereby Increased 25 manufacturing cost, limiting use of crumb to small granules and large powder (e 9, crumb withy the range of about 1mm to about 4mm, or, preferably, predominantly crumb within the range of about 2mm to about 3mm) may be preferred If minimizing manufacturing cost Is Important. 3 The use of powdered crumb Increases the strength of the resulting backing, and generates a smoother appearance, but Increases the cost of production, both In the need for additional 30 gnodng and In the need for the use of additional binder. Accordingly, the amount of powdered crumb can be adjusted to suit the needs of the product, typically, including powder of at least 3 10% by weight has been used The elastomer crumb is preferably at least partially comprised of crumbed vulcansed rubber The rubber Is preferably ntrle rubber The elastomer crumb may Include a combination of crumb sizes In addition to the powdered elastomer crumb.

The binder may be comprised of any of several different materials For example, the binder may be a polyurethane MDI binder Preferably it Is selected from the group consisting of 4,4-

methylene d-p-phenylene socyanate (MDI) polyurethane one- and twocomponent adhesives.

Advantageously the binder Is a solvent-free, one component (moisture cunng) polyurethane adhesive Such binder may be present at a level of from 4 to 12% Alternatively the binder may be a hot melt binder and Is desirably present at a level of from 3 to 10% When powdered elastomer crumb is Included In the backing and the binder Is a one component polyurethane adhesive, the binder level preferably lies in the range 9 to 20%, as may be determined by expenmentaton. 10 The backing may Include powdered or liquid additives selected from the group consshng of.

anti- microbial additives, anti-flammablty additives, pigments, such as iron oxide, and antistatic additives, such as carbon Inbred This provides added functionality to the mat Advantageously, a crumb rubber border extending beyond the periphery of the textile surface is provided on at least two opposite edges of the mat The crumb rubber border may be provided 15 around the entire periphery of the mat Advantageously, the textile surface comprises a tufted pile textile, including tufts of yarn tufted into a tufting substrate. Alternabvely, the textile surface comprises a knitted, woven or non-

woven textile, or a flock surface The mat may be a floor mat, a table mat, a bar runner or any other mat or mat-lke product 20 Often, commercial or retail floor mats are backed with PVC. The advantage of this mat backed with elastomer crumb Is that it is similar In cost of production to PVC and has superior appearance and feel to PVC Furthermore, it has much better low temperature flexibility than PVC, which means that the elastomer crumb backed mat lies better on the floor than a PVC backed mat The mat Is also less liable to become brittle with age than a PVC backed mat In 25 tests, we found that crumb rubber backed mats remained sufficiently flexible to unroll and lie flat Immediately after being removed from storage at minus 16 C Mats according to the invention also unroll more easily than PVC mats at higher temperatures and tend to give off less of a dstnctve odour of rubber than conventional vulcansed rubber mats The ability to roll up Is very important for commercial mats as they are often over em long and can be as long as 25m 3() It Is also Important for retail mats as they are frequently sold In rolled up form to enable the larger sizes to be carried home. The lie flatness or amount of rippling of the mat edges after both mats had been rolled up was visibly superior In the mat according to the Invention.

The Invention will now be further described by way of example only and with reference to the drawings, which are briefly described as follows

Figure 1 Is a cross-sectonal side elevation of a mat, figure 2 Is a top plan view of the mat; figure 3 Is an enlarged partial bottom view of the mat; figure 4 Is a side elevation of a press for manufacturing the mat, and 5 figures 5A to 5D are photographs showing In cross-secton the structure of various rubber crumb backing layers.

With reference to figures 1 and 2, a mat is shown with a textile surface 1 bonded to a nettle rubber crumb backing 2 In this case, the textile surface Is shown as a tufted pie textile It should be understood however that other textiles may also be used Including, for example, 10 knitted, woven and non-woven fabrics, as well as flocked surfaces The textile surface 1 Includes a tufted pile, which Is tufted onto a substrate (or primary backing), for example of woven or non-woven polyester or polypropylene The tufted pile can be cut, looped or both, and typically consists of cut pile Suitable textile materials Include polypropylene, nylon, cotton, blends thereof and any other Abbes or yarns that can be tufted Into 15 a tufting substrate to form a pile surface. The yarn may be solution dyed or the mats may be printed during or after manufacture.

The textile surface 1 Is slightly smaller than the backing, leaving a rubber crumb border 3 that extends around the periphery of the mat Alternatively, the border strips may be omitted entirely or two border strips may be provided on opposite sides of the mat, with no borders at the ends 20 of the mat This latter construction Is preferred for rolls or matting The width of the mat and the other dimensions may be any of those conventionally used for commercial or retail mats or any other suitable dimensions For mats with a low backing thickness, it Is advantageous for the textile surface to cover the whole upper surface of the backing For aesthetic reasons, such mats are often provided with what Is termed an "optical border", which is a dark printed area 25 around the periphery of the mat Figure 3 shows the rubber crumb backing 2 In more detail It generally comprises a series of rubber crumbs 6 bonded together with a binder (not shown), which bonds each crumb to the adjacent crumbs The binder also bonds the backing 2 to the textile surface 1. A plurality of voids 7 exist between the rubber crumbs, some of which may be partially or fully filled with the 30 binder Owing to the presence of the voids, the bulk density of the backing layer Is less than the density of the solid rubber material of which the crumbs are composed, and Is typically about 45%-70% of the solid rubber density

Generally, any batch of granules will include a distnbuton of granule sizes, the average granule size being significantly less than the maximum that wil pass through the mesh. For example, we have found when using a 4mm mesh that the majority of the granules lie In the range 1 to 3mm (' e. they will pass through a 3mm mesh but not a 1 mm mesh) Further, it should be noted 5 that the granules tend to be irregular In shape and often have a thickness that Is considerably less than the nominal granule size. Thus, with the compaction that occurs during the pressing process, we have found that a backing layer can be made using granules having a nominal size larger than the thickness of the backing layer.

The crumb Is preferably ntrle rubber, and Is preferably rubber from recycled Industrial mats IO The rental ndustnal segment Is an ideal source of raw material for the crumb because it ensures that low bleed, low staking nettle rubber crumb Is used as the startng point for the production of the mats of the Invention The crumb may Include some flock from the textile surface of the ongnal mat, perhaps in bonding relationship to the crumb The flock contort should preferably be as low as possible, most preferably less than 10% by weight 15 The crumb size may range from about 0.01 to 8 mm Generally, the size Is selected to be as large as possible for the use and properties required However, crumb larger than granules (he larger than about 6mm) may be regarded as excessively granular, and crumb that is smaller than about 0.8mm may be regarded as excessively costly (both In terms of supply and Increased binder requirements) Generally, it has been found that crumb within the range of 20 about 2mm to about 4mm Is preferred. Specifically, crumb that passes a 4mm aperture screen (he crumb predominantly of about 3mm or less) has been found to be particularly useful for floor mats In accordance with the teachings herein, powder (I e crumb less than 2mm In size) may be used as desired Crumb size can be chosen to give different amounts of resilience in the mat We have found that larger crumbs provide greater resilience.

2s Crumb may be mixed with powder of the same material or a different material to provide a greater tear resistance. We have found that the powder Increases the tensile strength for a given binder level The use of other additives In powdered or liquid form may provide the same or different advantages. Suitable additives Include, but are not limited to, anh-mcrobal materials, ant'-flammablty additives, odorants, colorants or pigments such as iron oxide 30 powder, ant'-static additives such as carbon fibres, fillers and other generally known addbves The binder may be either a heat setting or thermoplastic type Depending on the process utilized to manufacture the backing, the binder can be In liquid or powder form Preferably, the binder is selected from one of the following types: polyurethane reactive hotmelts, copolyester or copolyamde reactive and thermoplastic hotmelts, 4,4-methylene d'-p-phenylene socyanate 3s (MDI) polyurethane one- and two-component adhesives

It Is Important that the binder has good adhesive properties to ensure that the crumb Is well bound, and that sufficient free binders provided to be capable of forming a physical or chemical bond to the textile surface The binder should also exhibit sufficient cohesive strength to give the backing sufficient strength. When a tufted pile textile is used, the binder should be one that 5 cures or sets at a sufficiently low temperature and pressure that pile crush Is substantially avoided The binder may contain any of the known cross linkers or curing accelerators to suit the process and the desired properties of the mat being manufactured and the rubber being used.

The binder performs the dual function of holding together the crumb backing and bonding the 10 backing to the textile surface of the mat To perform both functions adequately we have found that binder levels should be In the range 2 to 12% by weight of the crumbs when chips or granules are used. Use of less than 2% binder gives a very poor tensile strength In the backing Use of greater than 12% gives a stiff backing and causes a skin to form. When rubber crumb powder Is added to the backing, the amount of binder needed for optimal properties Is greater 15 due to the higher surface area of the rubber crumb powder on a weight for weight basis. For powders, especially finer rubber crumb powders of size less than 0 5mm, the quantity of binder should lie In the range 9 to 20%, depending upon the size and quantity of the powder added.

Because the powder addition Increases the tensile strength, Inclusion of a little powder can Improve the strength of the backing without Increasing the binder content excessively.

20 Generally, there is an Inverse relationship between the binder content and size of the rubber crumb, and between the binder content and pressure applied to the rubber crumb while forming the backing layer Therefore, as the crumb size and the pressure Increase, the binder content decreases. The binder content also depends on other factors, such as the type of binder, the rubber material used and the type of fabric, and can be determined by routine experimentation.

25 For example, the binder may be a liquid polyurethane MDI binder, In which case it Is preferably present at a level of from 4 to 12% if the backing consists primarily of chips or granules. The binder may contain further additives that are In liquid form and are compatible with the binder, such as colorants, plashcsers and perfumes The binder may also contain other additives, such as those listed as crumb additives, provided that they are suitable for addition In a liquid 30 medium The binder may alternatively be a thermoplastic or thermosettng hot melt powder, in which case it Is preferably present at a level from 3 to 10% If the backing consists pnmarly of chips or granules. A powdered binder may also contain other additives such as those listed as crumb additives, provided that they are suitable for addition in a powder medium 35 The preferred ranges for binder content may thus be summarized as follows

Backing of chpsigranules: binder content In range 2 to 12%, preferably 4 to 12% with an MDI binder or 3 to 10% with a hot melt binder Backing with > 10% powder binder content In range 9 to 20%, preferably 14% or more.

Examples of mat products according to the Invention are given In Table 1 S Table 1 - Example Products Property Floor mat - tufted Floor mat - tufted Bar runner- Poster mat-

polypropylene nylon on rubber knitted polyester woven polyester I fabric on rubber granule backing fabric on rubber on rubber granule powder backing with printed optical powder backing backing borders Textile Type Polypropylene Nylon 6 Polyester Polyester Weight 500 gm' 600 gm 237 gm 200 gm Method Tufted Tufted Knitted Woven Tufting substrate 80 gm Polyback 140 gm Colback nla n/a Backing Matenal 0.8mm powder 3mm granule O 5mm powder 4mm granule (screen size) Thickness 1 5 mm 4.0 mm 1 0 mm 1 5 mm Weight 2000 gm 3000 gm 1 333 gm' 2000 gm' Total Weight 2580 gm' 3740 gm 1570 gm 2200 gm' Borders 15 mm None None None gm2 is grams per square meter A process for making the mat of figures 1-3 will now be described with reference to figure 4, which Is a schematic exploded cross- section of a mat as laid up In a press during manufacture The press 9 Includes a heated metal platen 10, above which there Is an Inflatable diaphragm 10 12, mounted on a frame 14 The frame 14 may be either fixed or moveable, depending on I whether the press has a fixed or variable opening aperture. A conveyor belt 16 made, for example, of PTFE-coated woven glass fabric extends around and beyond the heated platen 10, allowing laid up mats to be transferred In and out of the press 9.

The lay up consists of the following items placed in order on the conveyor belt 16. First, a 15 mixture of rubber crumb, binder and any other required additives is made up and spread evenly i onto the conveyor belt 16, forming a loose crumb layer 18 having a thickness, a width and a length that are sightly greater than the required dimensions of the finished backing layer 2. The I binder may, for example, be a hot melt powder, in which case the amount of binder typically vanes between 3% and 10% by weight, depending on the size of the crumbs and the amount

and type of any optional additives A die cut fabric layer 20, for example of tufted pile textile on a suitable substrate, is placed on top of the loose crumb layer 18; the length and width of the fabric layer preferably should be slightly less than the equivalent dimensions of the loose crumb layer If a rubber border Is S required The laid up mat is then covered with a release sheet 22 of PTFE-coated woven glass fabric, to prevent the rubber backing sheet 2 stacking to the diaphragm 12 The press is heated to a temperature of about 125 C. The conveyor belt 16 is advanced to position the laid up mat between the platen 10 and the diaphragm 12, and the diaphragm 12 is then Inflated, for example, to a pressure of about 4 pounds per square inch, to press the lard up I 10 mat against the heated platen 10, typically for a cycle time of 10 mmutes The heat from the platen 10 activates the binder, thereby binding the rubber crumbs together and forming the backing layer 2. At the same time, the pressure from the diaphragm 12 slightly compresses the backing layer 2 to ensure a good bond between the granules, and presses the fabric layer 1 against the backing layer 2, ailowng the binder to bond the two layers together.

15 After completion of the pressing process, the diaphragm 12 Is deflated and the rubber backed mat Is removed from the press 9 and allowed to cool The release sheet 22 Is then removed and, If necessary, the edges of the rubber backing layer 2 are trimmed, for example using any suitable knife or other cutting means, for example, a gullohne We have found that by using the process described above, we can control the flexibility and 20 strength of the backing by adjusting the pressure applied to the backing in the press. By Increasing the pressure the tensile strength of the backing can be increased, and by reducing the pressure the flexibility of the backing can be Increased. The desired performance characterishcs of the backing can thus be achieved by careful control of the backing pressure.

Also, when tufted pile textiles are used, the problem of pile crush can be substantially avoided 25 This Is because the press operates at a much lower pressure (typically, 4 psig) and temperature (about 125 C) than Is usual in a conventional mat press, which typically operates at a pressure I of 20 to 40 pang or higher and at temperatures above 160 C The lower pressure and temperature are possible because the rubber crumb Is already vulcanized and the heat and pressure only have to be sufficient to activate the binder and press the granules together so that 30 they bond to one another and to the fabric layer. In a conventional mat making process, a much higher pressure and temperature is required to soften and cure the vulcansed rubber backing, i and to press the fabric layer into the backing The mats provide a higher level of comfort and are lighter than compression moulded mats, which have hgh-densty backings The mventve mat Is suited to the retail and commercial 35 segments

Example

A batch of 0.8 to 3mm rubber crumb was made up by granulating a sheet of vulcanised Futile rubber in a granulator with a 3mm screen and then passing the granules over a 0 8mm screen to remove fines smaller than 0 8mm The granules were then mixed with 8% MDI binder The 5 mixture wasdivided up and sample rubber mat backings were made by spreading the crumb mixture evenly with a thickness of 8 mm and then pressing the mixture using an air bag press at venous pressures to produce a series of samples The pressure ranged from no pressure in the air bag through to 45 psig. All the rubber backing samples so formed were set or pressed at 125 C for 10 minutes A 25mm square section was then cut from each sample and its I 10 thickness and weight were measured From this, the density of the sample and the bulk density of the rubber crumb layer was determined, expressed as a percentage of the density of the material from which the crumb was made. The data are given in Table 2.

Table 2 -Density Test Data ! Sample | Pressure I Thickness Thickness Weight Volume | Density Bulk psig mm % __ cm3 ghm3 Density A 1 0 8. 1 100 2 8 5 06 0 55 45

B 2 6.2 78 1 2.8 3 87 0.72 59

j C, 4 5 4 68 2 6 3 37 0 77 63 D 8 54 68 2 9 337 0 86 70

! _

E 16 5 0 63 3 2 312. 1.02 84

_. F 32 4.3 54 2.8 1 2 68 1.04 j 85 j I _ G, 45 3.9 49! 2.7 ' 2.43 1 11 91

Royal, 7 3 | | 5.0 4.56 1 10 90 | I Rubber I l l 1 22 100 | 15 The sample referred to as "Royal" Is the backing layer of the prior art Royal" mat referred to

previously, which Is formed by compression mouldng rubber crumb in a fixed platen press to form a very dense backing. The sample referred to as "Rubber" Is a solid vulcansed rubber i backing of a conventional floor mat It can be seen from Table 2 that the density increases as the pressure applied increases The 20 maximum density achieved was 1 11 g/cm3, equivalent to a bulk density that Is 91% of the density of the solid rubber backing Theoretically, if the backing sample were 100%

compressed to remove all voids the density would be about 1 22 gicm3to match that of the solid rubber backing of the conventional vulcansed mat referred to as "Rubber" From the table, it can be seen that the density of the compression moulded product (the "Royal" mat) Is about the same as the density we obtained using a 45 ps' pressure 5 Table 2 also gives a general view of the backing thickness reduction from around 8mm before to around 4-6mm after pressing, representing a reduction of up to 50% of its original thickness. I The samples were then tested to determine their deformability. This test was done with a thickness gauge with a 10mm diameter foot Weight was applied to the measuring plunger of I the thickness gauge first the new backing thickness was measured with Bog weight and then 10 the thickness was re-measured with a 800g weight The deformability Is the percentage fall In the thickness at Bog ioadng when the loading pressure was Increased to 80Og The results are shown in Table 3.

Table 3 - Deformablilty Test Data I Sample ID Pressure | 60 9 800 g Deformability % | A 1 0 7.65 4 0 47.7 1

! B 2 5.70 4 3 24.6

4 5 10 42 | 17.6

l 1 D I 8 5.30 4 55 14 2

E 16 480 43 ', 10.4

F 32 415 375 I 96

G 45 3 70 3 5 _ 5 4

Royal 7 45 7.05 5 4 I Rubber 6 10 5.6 8 2 15 From Table 2 it can be seen that there is a correlation between formation pressure and density, and from Table 3 it can be seen that there is a correlation between pressure (density) and deformability. This correlation may be expressed as follows: the higher the formation pressure, the higher the density, and the higher the density, the lower the deformability In Tables 2, 3 and 4, the sample referred to as "Rubber" Is a commercially available vulcansed 20 rubber backed Industrial mat The vulcansed rubber Is softer and therefore more deformable than the high pressure crumb backings because of the presence of binder in the latter The

binder material Is relatively hard, compared with vuicansed rubber, and this reduces the flexibility of the backing.

In the mat made by compression mouldng (the "Royal" mat), the bulk density of the mat backing was about 90% of the density of the material from which the crumb was made and is 5 usually In the range of 80-95% The backing is harder than the material from which the crumb was made because of the presence of the binder.

On the other hand, using the process according to the Invention, the bulk density of the backing can be vaned to lie within 45-90% of the density of the material from which the crumb was made. Preferably, the bulk density of the backing is made to lie within 45-70%, and more 10 preferably within 55-70%, of the density of the crumb material This provides a backing with a deformability of about 14-50%, more preferably 14-25%, which Is better than that of a compression moulded mat and comparable to that of a conventional rubber backed mat The Invention also offers the advantage of a lighter weight mat that Is more easily washed and dried and easier to carry and transport, whilst still being a rubber backed mat This also has the I5 advantage that the product density can be varied by a minor process change to enable production flexibility. Additives could also be Included In the crumb and binder mix to further control or change the density If required.

The effect of different formation pressures on the structure of the backing layer Is shown photographically In figures 5A to 5D figure 5A shows a cross-section at a magnification of 20 about 10x through a backing layer made up from 1 5mm rubber granules together with 8% MDI binder and 5% yellow oxide (which was added to binder to Improve its vsblty), and pressed at a pressure of 2 PSI Some of the granules were coloured blue and others were coloured black, to allow the boundaries between the granules to be seen more easily (the blue granules appear a lighter shade of gray). The Individual granules can be easily Identified and are substantially 25 undeformed, having straight edges and sharp corners The granules are packed together as a loose conglomeration giving the backing a sponge-like appearance. Many voids can be seen between the granules, those voids being generally only partially filled with binder figure 5B shows a similar backing, produced at a pressure of 10 PSI. The backing has a tighter, more compact structure and some slight deformation of the granules can be seen. This 30 Increases the area of contact between adjacent granules and increases the tear strength of the backing Nevertheless, many voids are still visible between the granules, which are only partially filled with binder.

figure 5C shows a backing made using the same mixture of granules and binder, but using a compression mounding process In a 20 tonne press In this case. severe deformation of the 35 granules has taken place and the boundaries between adjacent granules are almost

unidentifiable, except where the granules have different colours. The backing layer Is dense and virtually solid, with hardly any voids between the granules figure 5D shows a cross-section through a conventional compression moulded mat (the prior art"Royal" mat) As with the backing layer shown In Figure 5C, the boundaries between 5 adjacent granules are almost unidentifiable and the backing layer Is dense and solid, with hardly any voids (except where the backing layer has fractured) Tear Strength Test To test the strength of the granulated rubber backing, a batch of samples was made up using different formation pressures, ranging from no pressure in the air bag through to 8 psg. All the 10 rubber backing samples so formed were set or pressed at 125 C for 10 minutes. Six test pieces were then cut from each sample and the tear strength of each test piece was measured, with three measurements being made In each of two orthogonal directions. The results are shown In Table 4

Table 4 - Tear Strength Test Data Formabon | Tear Strength - Direction 1 Tear Strength - Direction 2 Av Pressure Nlmm2 Nlmm2 tear I PSI strength Test 1 Test 2 Test 3 Test 4 Test 5 Test 6 Nlmm2 i 1 _ 0 1 0 09 0 11 0. 06 0.08 0 06 0.08 0 08

2 0 89 0 88 0 95 0.82 0 98 0 81 0.89

4 159 1.56 1 51 1 48 1.45 14

i 8 1 1.41 1 55 1.57 1 52 1.55 1 148 1 51 Table 4 shows that there Is a correlation between formation pressure and tear strength, the strength increasing rapidly up to a formation pressure of about 4 PSI, but with no significant additional Increase in strength at higher formation pressures. We have found that a tear strength of about 0.8N/mm2 or higher is quite adequate for many mat applications, even though 20 this is considerably less than the tear strength of a conventional solid rubber mat backing Pile Crush Test For this test, we made a number of mat samples, each including a tufted pile surface and a rubber crumb backing made using the same pressing temperature, hme and pressure values as

set out in Table 2 The extent of pile crush and the commercial acceptable of the different mat samples were then assessed subJecbYely. We found that for pressures of about 8psig and lower, pile crush was relatively minor and the product was commercially acceptable However, at pressures above about 8psg, significant pie crush occurred and the product was considered 5 commercially unacceptable without subsequently being laundered or processed in some other way to raise the pile The preferred tufted pile mats are therefore those manufactured at a pressure of about 8psig or less, which have backings with a bulk density In the range 45- 70% of the density of the solid rubber material from which the rubber crumb is derived. The best mats were those manufactured at pressures of 2- 8psg, which have a bulk density In the range of 10 about 55-70%.

Low T mperature Recovery Test.

For this test a 300 mm x 200 mm sample of each product to be tested was conditioned at a room temperature of 22 C for 2 hours and then rolled lengthwise around a 40mm diameter tube and secured with a cable be. The samples were then placed In a freezer and kept at a I S temperature of -1 6 C for 24 hours. The samples were removed from the freezer, the cable be was cut and the samples were then left at 22 C for 10 minutes to relax on a flat, wood surface.

Measurements were then made of the height, if any, of the ends of the mat samples above the flat surface due to the curl of the sample. Repeat measurements were made at 20 minutes and 60 minutes following removal from the freezer.

20 Table 5 shows the results of the above test when comparing. a conventionally backed nitnle rubber mat (A), a commercially available mat backed with PVC (B), a prior art rubber crumb

backed mat formed by compression mounding In a fixed platen press to form a very dense backing (the "Royal', mat), and a mat according to the Invention backed with granulated ntrle rubber crumb (D).

25 Table 5

| Prior art mats Inventive mat:

I Time I A Regular rubber | B PVC backed I C Compression D Rubber crumb I _ backed mat | mat moulded mat backed mat +10 minutes Flat (Omm) 1 37mm SOmm 10mm +20 minutes Flat (Omm) 7mm 6mm Flat tommy _ I 11 +60 minutes | Flat(Omm) 2mm 2mm Flat(Omm)

The mat according to the invention outperforms both the PVC backed mat and the compression moulded rubber crumb mat and it is not significantly different In performance from a high specification conventonai rubber backed mat

Sand R_tention Test 5 For this test two equal size samples of a mat (0 05781 m2) were cut out. Each sample was weighed They were then fixed to the inside of a tetrapod chamber A tetrapod Is a known piece of testing equipment used to measure wear of carpeting and the like. 1000 9 of dry sand with a particle size distribution as shown In Table 6 was added along with five golf balls to provide agitation 10 Table 6

Particle size mm Weight % 0.00 - 0 25 7 0

0 25 - 0.50 71 0

_ 0.50 - 0 71 15.7

_ 0 71 -1 00 3 5

1.00-200 1 7

2.00 - 2.80 016

_.. 2.80 - 4.00 0.02

400-6.70 0

6 70 and above 0 The chamber was then sealed to prevent either the golf balls or the sand leaking out during the test and it was set revolving for 1000 revolutions. On completion of the test, each sample was removed and the weight Increase of the sample recorded The amount of sand retained In each 15 sample was then calculated and expressed as the amount of dry sand retained In g/mZ Two mats with Identical tufted pile construction were subjected to this test. The first mat was a tufted nylon cut pie conventional rubber backed mat, which had been fabricated in an air bag press at 1 65C and 30 psi. The mat was not washed prior to the test The second mat was a tufted nylon cut pile mat with a rubber crumb backing, which had also been fabricated In an air 20 bag press but at a lower temperature and pressure The sand retention results were as follows Sample of prior art conventional rubber backed mat A weight increase = 723 g/m2

Sample of inventive crumb rubber backed mat B: weight Increase = 2655 g/m2

Production of a conventional rubber backed mat significantly flattens the pile on the mat. The lower temperature and pressure possible when using the same type of press (with a pressunsed air bag and a heated platen) to produce a rubber crumb-backed, textile placed mat according to the Invention results In a mat that does not suffer significantly from pile crush This gives a mat having, Immediately after manufacture, good dust control properties without being laundered This good dust control performance is exemplified by a sand retention value In excess of 2000 gim2 for the typical nylon tufted pile used In this test The sand retention performance for a mat according to the invention Is far superior to the sand retention performance of the conventional rubber- backed tufted nylon cut pile mat, prior to washing The 10 uncrushed pile also exhibits better"feel" by way of a more luxurious texture The mats according to the Invention exhibit superior fire resistance to those made from conventional nitnle rubber backing of the same thickness When tested according to BS4790, mats made from powder ntnle rubber crumb and granule nitrile rubber crumb showed significantly higher resistance to gnbon when compared to a mat made from conventional 15 nettle rubber backing This Is recorded in Table 7 Table 7

Rag r me w U. so id Mat with crumb rubber backing granule backing Time to extinguish (s) 170 50 Radius of effects top (mm) 50 25 _ Radius of effects lower (mm) 50 25 This can be further Improved by the addition of more binder and/or antr-flammablty additives to the backing and is especially useful when used In conJunchon with a low flammability textile 20 surface Such a low flammability textile surface may, for example, be one that Is predominantly a woollen construction When compared with PVC backed mats, the mats of the invention that have 4mm or larger crumb rubber In the backing have better resistance to movement on carpets. On average, these mats according to the Invention display significantly Improved resistance to movement on 2s carpets compared with PVC backed mats.

Other mats can also be made according to the nvenbon Including, for example, floor mats such as poster mats or foam sandwich mats, table mats, drinks mats and bar runners

Claims

1 A mat with a textile surface and an elastomer backing that includes elastomer crumbs and a binder, characterized in that the elastomer backing includes voids between the elastomer crumbs

2 A mat according to claim 1 wherein the elastomer crumb is crumbed vulcansed rubber

3. A mat according to claim 2 wherein the rubber is nettle rubber.

4 A mat according to any preceding claim wherein the elastomer backing has a bulk density I less than the solid density of the elastomer crumb material

5 A mat according to claim 4, charactensed in that the elastomer backing has a bulk density In the range 45 to 70%, preferably 55 to 70%, of the solid density of the elastomer crumb matenal.

6 A mat according to any preceding claim, charactersed In that the backing has a density of less than 19 /cm3

7 A mat according to claim 6, charactensed In that the backing has a density In the range 0 5 to O.9g /cm3, preferably 0 7 to 0 99 /cm3

8 A mat according to any preceding claim, characterized In that the elastomer backing exhibits a deformability, as measured by the test herein defined, of at least 14%, preferably 14 to 50%, more preferably 14 to 25%

9 A mat according to any preceding claim, characterized In that the elastomer backing exhibits a tear resistance strength of at least 0 8 N/mm2

10 A mat according to any preceding claim in which the backing has a thickness of at least 1 mm

11 A mat according to any preceding claim In which the crumb size Is less than 5 mm diameter and is preferably substantially In the range 2 to 4 mm

12 A mat according to any preceding claim m which the elastomer crumb backing Includes at icast 10% by weight powdered elastomer crumb.

13 A mat according to any preceding claim in which the binder Is present at a level of from 2 to 20%

14 A mat according to claim 13, In which the elastomer crumb backing Includes less than 1% by weight powdered elastomer crumb and the binder Is present at a level of from 2 to 12%

15 A mat according to claim 13, wherein the elastomer crumb backing includes at least 10% by weight powdered elastomer crumb and the binder level lies In the range 9 to 20%, preferably about 14%.

16 A mat according to any preceding claim m which the binders a polyurethane MDI binder

17 A mat according to claim 16 In which the binder Is selected from the group consisting of 4,4-methylene d-p- phenylene isocyanate lMDI) polyurethane one- and two-component adhesives

18 A mat according to claim 17 in which the binder Is a solvent free one component polyurethane adhesive

19. A mat according to any one of claims 1 to 15 In which the bindems a hot melt binder

20 A mat according to any preceding claim m which the backing Includes powdered additives selected from the group consisting of ant'-mcrobal additives, ant'-flammablity additives, pigments, such as Iron oxide, and anti-statc additives, such as carbon flbres

21 A mat according to any preceding claim, charactensed In that a crumb rubber border extending beyond the periphery of the textile surface Is provided on at least two opposite edges of the mat

22 A mat according to claim 21 comprising a crumb rubber border extending around the entire periphery of the mat

23 A mat according to any preceding claim, characterized In that the unwashed textile surface has a sand retention value of at least 1000 g/m2.

24 A mat according to any preceding claim, characterized In that the textile surface comprises a tufted pile textile, Including tufts of yarn tufted Into a tufting substrate

25. A mat according to any preceding claim, charactensed In that the textile surface comprises a knitted, woven or non-woven textile, or a flock surface.

26 A mat according to any preceding claim, which Is a floor mat

27. A mat according to any one of claims 1 to 25, which Is a table mat.

28 A mat according to any one of claims 1 to 25, which Is a bar runner