Patent Publication Number: US-2005118907-A1

Title: Washable floor mat

Description:
The present invention relates to a washable floor mat having a tufted pile textile surface and an elastomer backing layer, which is suitable for periodic washing, for example in a laundry. In particular, the invention relates to a mat with a textile surface made wholly or partially of cotton. The invention also relates to a method of making such a mat.  
      Industrial or rental mats are generally owned by a laundry, which rents the mats to its customers. The mats are usually placed at the entrances to shops, offices and factories to remove dirt and moisture from the feet of pedestrians entering the building. Periodically, soiled mats are exchanged for clean ones and the soiled mats are returned to the laundry for washing and drying. Owing to their intended use, it is essential that the mats are durable and have very high levels of washability.  
      These mats typically comprise a tufted pile textile top surface having good moisture and dirt absorbing properties and a backing layer of an elastomer material, for example rubber, which may be either solid or foamed.  
      Various different textile materials are available, including synthetic materials such as high twist nylon and natural fibres such as cotton. Nylon mats have very good dust control properties, are hard wearing and can be washed and dried economically. However, they do not have very good moisture absorbing properties. Cotton mats on the other hand have very good moisture absorbing properties, but they tend to be less durable than nylon mats. It is also known to provide a washable floor mat with a tufted pile textile surface that comprises a variety of fibre types. For example, GB 2362568A describes a mat having a textile surface that includes 50% tufts of nylon and 50% tufts of a blended yarn that includes cotton, an anti-microbial acrylic fibre and a low melting point polyester fibre, which is partially fused to the other two fibres.  
      A common problem with many floor mats is that they can suffer from creep (gradual movement) during use, as they are walked on. This can be caused by movement of the underlying carpet pile when the mat is placed on top of carpet, or the presence of sand or grit under the mat when it is used on hard flooring.  
      A solution sometimes proposed for the problem of creep is to furnish the mat with small protrusions (“cleats”) that extend downwards from the lower surface of the rubber backing. The cleats are effective to grip textile, flooring such as carpet and also serve to lift the bottom surface of the mat off the floor, to increase the grip and reduce creep on hard flooring. A suitable process for manufacturing a cleated mat with a solid rubber backing layer is described in WO 01/21875, and the formation of a cleats on a foam-backed mat is described in WO 01/90463.  
      We have found that if cleats are provided on mats having a cotton yarn tufted pile, they tend to destroy the cotton surface when the mats are exposed to washing and drying. The cleats and the motions of the laundry equipment have an effect like a carding process on the textile and pull the cotton fibres out of the yarn. This leads to an unacceptable rate of wear for the textile surface of the mat and to a loss of appearance through linting of the mat surface, and has until now precluded the use of cleats on cotton-faced mats.  
      It is an object of the present invention to provide a mat with a tufted pile textile surface made wholly or partially of cotton, which mitigates at least some of the aforesaid problems.  
      According to the present invention there is provided a washable floor mat having a textile layer and a backing layer, wherein the textile layer includes a tufted pile textile having tufts containing cotton fibres, and the backing layer is made of a foamed elastomer material and includes a plurality of cleats on a lower surface of the backing layer.  
      We have found that if the backing layer is made of a foamed elastomer, the cleats have a much less aggressive effect, significantly reducing linting of the cotton fibre during laundering. This makes it feasible to provide cleats on a washable floor mat having a cotton textile layer, which reduces movement of the mat during use.  
      The use of foamed rubber also reduces the weight of the mat, so making it easier and cheaper to transport, and increases its flexibility. We have also found that mats with a foam, rubber backing layer (including mats with and without cleats) are less prone to move when stepped on, particularly when placed on top of carpet.  
      The use of a foam backing in combination with the use of tufts of blended yarn provides the advantage that, when the mat is laundered, there is a synergistic saving of energy resulting from the lower weight of the foam backing in combination with the lower residual water content (i.e. the water remaining at various stages of the drying process) of the blended yarn as compared with 100% cotton yarn.  
      Advantageously, the tufted pile textile includes tufts of a blended yarn including at least 40% cotton fibres and at least 25% polyester fibres.  
      We have found that a mat with a tufted pile textile of blended cotton and polyester is much harder wearing than a 100% cotton mat, and that linting of the cotton fibre during washing and drying is significantly reduced.  
      The blended cotton/polyester tufted pile textile is also as effective at removing moisture from the feet of pedestrians as a 100% cotton textile layer. However, it is much easier to dry, requiring significantly less energy input during spinning and tumble drying. The mat therefore has a longer useful lifespan and is much cheaper to clean, thereby significantly reducing the operating costs of the laundry. We have also found that the blended yarn has much better colour retention than a pure cotton yarn.  
      Preferably, the blended yarn includes at least 40% cotton fibres and at least 25% polyester fibres, more preferably at least 50% cotton fibres and at least 35% polyester fibres. We have found for example that blends of 65% cotton with 35% polyester and 50% cotton with 50% polyester are particularly effective.  
      Advantageously, the cotton and polyester fibres together comprise at least 90%, preferably at least 95%, and more preferably at least 99%, of the total fibre content of the blended yarn. The blended yarn may also include some other fibres, e.g. polyamide, but generally this should not exceed 5-10% by weight.  
      The cotton and polyester fibres of the blended yarn are preferably spun together. We have found that the beneficial effects of the blended yarn are particularly pronounced when the cotton and polyester fibres are in intimate mechanical contact with each other, which is best achieved by mixing the fibres and then spinning them together into a yarn.  
      The tufts of blended yarn may include from one to six plies of yarn, preferably three or more plies. The overall decitex of the blended yarn should be similar to the decitex of a cotton yarn and the number of plies used should also ideally match that of a typical cotton yarn. For example, the yarn may include six plies and have a decitex of about 4400.  
      The polyester fibre may have a denier of 1 to 6, preferably 1 to 2, more preferably about 1.5. The use of fine denier polyester fibre results in a larger number of fibres for the same proportion of polyester in the blend. It is believed that this improves the properties of the blend for mats.  
      The blended yarn may include up to 10% microfiber polyester of less than 1 denier, preferably approximately 0.9 denier. For example, we have found that a blend of 50% cotton with 45% polyester and 5% polyester microfiber of 0.9 denier is particularly effective.  
      The textile layer may include a woven or non-woven substrate, which may be formed of polyester, polypropylene, a copolymer or any other suitable material.  
      The backing layer may be made of foamed rubber, preferably foamed nitrile rubber. The thickness of backing layer may be from 0.5 mm to 5 mm, preferably 0.8 mm to 3 mm.  
      Advantageously, the backing layer has a Shore A hardness in the range from 20 to 40. Advantageously, the foamed elastomer material has a degree of expansion in the range 1.5 to 2.5.  
      Preferably, the cleats are formed partly from foamed rubber and have a thick skin of dense rubber on at least their lower surface. The cleats are preferably distributed over substantially the entire lower surface of the backing layer, and may be arranged in a preferred pattern, for example along a substantially rectilinear grid, with rows and spaces of approximately the same width between the rows.  
      According to another aspect of the invention there is provided a method of manufacturing a washable floor mat having a tufted pile textile layer and a foam elastomer backing layer, the method including the steps of providing a mould having a plurality of recesses, moulding a foam elastomer material against the mould to form a backing layer having a plurality of cleats on a surface thereof, and bonding the backing layer to a tufted pile textile having tufts containing cotton fibres.  
      Advantageously, the moulding and bonding steps are carried out substantially simultaneously in a heated press. Advantageously, the foam elastomer material is made of foamed rubber, preferably foamed nitrile rubber, and is vulcanised in the heated press.  
      The tufted pile textile is preferably formed by tufting a yarn onto a woven or non-woven substrate. The tufted pile textile surface preferably includes tufts of a blended yarn including at least 40% cotton fibres and at least 25% polyester fibres, and the blended yarn is preferably made by spinning the cotton and polyester fibres together. 
    
    
      Embodiments of the invention will now be described, by way of example, with reference to the accompanying drawings, in which:  
       FIG. 1  is a top plan view of a mat according to the invention;  
       FIG. 2  is a cross sectional side elevation on line II-II of  FIG. 1 ;  
       FIG. 3  is an enlarged bottom plan view of a portion of the mat shown in  FIG. 1 ;  
       FIG. 4  is a cross sectional side elevation on line IV-IV of  FIG. 3 , and  
       FIG. 5  is a side elevation of a mat assembly laid up in a heated press. 
    
    
      The mat shown in FIGS.  1  to  4  includes an upper textile layer  1 , which is bonded to a lower backing layer  2  of vulcanised foamed nitrile rubber. The backing layer  2  is preferably slightly larger than the textile layer  1 , leaving a rubber border  3  that extends around the periphery of the mat. The overall size of the mat is typically 85 cm×150 cm. A pattern of cleats  4  (which can be seen in  FIGS. 3 and 4 ) is provided on the lower surface of the backing layer  2 .  
      The textile layer  1  comprises a tufted pile  5 , which is tufted onto a substrate  6 , for example of non-woven polyester or woven polyester or polypropylene. Typically the tufted pile  5  has a pile length of about 10 mm, and a pile weight of about 870 gm −2 . The substrate  6  typically has a weight of approximately 100 gm −2 .  
      The tufted pile  5  may be made up of tufts of 100% cotton yarn or tufts of a blended yarn that includes a substantial proportion of cotton fibres. In a preferred embodiment, the tufts are made of a blended yarn that includes at least 40% cotton fibres and at least 25% polyester fibres, by weight. Preferably, the cotton and polyester fibres together comprise at least 90% of the total fibre content of the blended yarn. For example, we have found that blends of 65% cotton with 35% polyester and 50% cotton with 50% polyester are particularly effective. The polyester fibre typically has a denier in the range 1 to 6, preferably 1 to 2, most preferably about 1.5.  
      The blended yarn is made by mixing the cotton and polyester fibres and spinning them together. This increases the mechanical contact between the fibres and improves the performance of the yarn. Typically, the tufts of blended yarn include three or more plies of yarn. Typically, the tufts of blended yarn include three or more plies of yarn. For example, the yarn may include six plies and have a decitex of about 4400.  
      The blended yarn may optionally include up to 10% microfiber polyester of approximately 0.9 denier. For example, the blend may consist of 50% cotton with 45% polyester and 5% polyester microfiber.  
      The tufts of cotton or blended cotton yarn generally cover substantially the whole of the upper textile layer  1 . However, the textile layer  1  may also include one or more areas of other textiles, including knitted, tufted, woven and non-woven fabrics. For example, the textile layer  1  may include areas of high twist nylon tufted pile textile, knitted polyester fabric or flock fabric.  
      The backing layer  2  is made of a foamed rubber, preferably a closed cell foamed nitrile rubber having a degree of expansion of between 1.5 and 2.5. The use of foamed rubber reduces the weight of the mat and increases its flexibility and stability. The rubber backing layer  2  typically has a thickness of 0.5 to 5 mm, preferably 0.8 to 3 mm. For a backing with a thickness of 1 mm, the weight is typically 806 gm −2 , as compared to 1160 gm −2  for solid rubber. The Shore A hardness of the backing layer  2  should lie in the range from 20 to 40. Traditional solid rubber for washable mats has a Shore A value in the range 40 to 60.  
      The backing layer  2  is provided with cleats  4  formed from the foamed rubber. The cleats  4  are advantageously cylindrical in shape and have a diameter greater than their length. The diameter of each cleat is preferably in the range 0.4 to 6 mm, more preferably 0.8 to 3 mm, and most preferably about 2.5 mm. For a cleat with a diameter of 2.5 mm, the length is typically 1.26 mm. Advantageously, the cleats  4  have a thick skin of dense rubber on at least their bottom surface.  
      The cleats  4  are desirably distributed over substantially the entire lower surface of the backing layer  2 . Most desirably they are arranged in a pattern of rows  7  with spaces  8  of approximately the same width between the rows. This allows one mat to slide more easily against another when they are stacked back to back.  
      The mat is manufactured by vulcanising the textile layer  1  to a sheet of nitrile rubber  2  in a heated press. The rubber includes a heat activated blowing agent. Any suitable blowing agent may be used: for example, we use an organic blowing agent comprising a blend of sulphohydarzide and activated azodicarbonamide. A suitable manufacturing process is described in WO01/90463, the entire content of which is incorporated by reference herein. A laid up mat assembly is shown in  FIG. 5 .  
      The mat assembly is laid up on a bottom release sheet  9 , prior to being placed in a heated press. The bottom release sheet  9  is made for example of PTFE-coated woven glass, and includes a plurality of perforations  10 . Underneath the backing layer is a cushioned platen liner  11  of silicon rubber. A top release sheet  12  is placed on top of the mat assembly. The press consists of a heated metal platen  13  and an inflatable diaphragm  14 , which is secured to an upper plate  15 .  
      The laid-up mat assembly is pressed in the heated press, for example at a temperature of 170° C. and a pressure of 30 pounds per square inch, applied for a cycle time of up to twenty minutes. The heat from the press activates the blowing agent, causing the rubber to foam and expand to approximately 1.5 to 2.5 times its original volume. The rubber is also softened and forced into the perforations  10  in the bottom release sheet  9  to form the cleats  4 . At the same time the heat vulcanises the rubber and thereby bonds the upper textile layer  1  to the rubber backing layer  2 .  
      Once this process has been completed, the mat is removed from the press and allowed to cool, after which the release sheets  9 ,  12  are removed and, if necessary, the edges of the backing layer  2  are trimmed. The mat may then be laundered, to raise the pile of the tufted dust control fabric. Optionally, the backing layer  2  may be perforated, to allow the passage of water during a spin drying process.  
      The performance of mats according to the invention was compared with that of conventional cotton mats, by performing the tests set out below.  
      Laundry Test A  
      Six sets of sample mats were manufactured using three different tufted pile fabrics and two different backings, with the following specifications: 
          Fabric A: Cotton yarn comprising 100% cotton in a 4250 decitex 6 ply yarn     Fabric B: Cotton blend comprising 65% cotton and 35% polyester in a 4300 decitex 6 ply yarn     Fabric C: Cotton blend comprising 50% cotton, 45% polyester and 5% polyester microfibre in a 4450 decitex 6 ply yarn        

      In Fabrics B and C, the polyester fibre had a denier of 1.5 and in Fabric C the microfiber polyester had a denier of 0.9. 
          Backing A: Solid rubber with cleats     Backing B: Foam rubber with cleats        

      These mats were washed, spun and tumble-dried a number of times and then weighed to determine the amount of yarn loss. The results are shown in Table 1.  
                                       TABLE 1                                   1   50   100   150   175           cycle   cycles   cycles   cycles   cycles                                                            100% cotton on solid   3.75%   20.00%   30.00%   40.05%   43.13%       rubber       65% cotton 35% poly-   1.88%   16.25%   28.13%   36.26%   40.00%       ester on solid rubber       50% cotton 45% poly-   2.50%   15.63%   26.88%   33.75%   37.50%       ester 5% polyester       microfibre on solid       rubber       100% cotton on foam   2.10%   14.94%   24.93%   31.77%   34.90%       rubber       65% cotton 35% poly-   1.30%   13.91%   20.54%   24.97%   26.50%       ester on foam rubber       50% cotton 45% poly-   1.32%   12.86%   19.60%   23.86%   26.32%       ester 5% polyester       microfibre on foam       rubber                  
 
      It is apparent from the above results that the mat with foam rubber cleats suffered far less linting than the mat with solid rubber cleats. The use of a blended cotton/polyester yarn helped to reduce linting still further. The mats according to the invention thus significantly outperformed the prior art mat and in use would have a far longer useful life.