Dust mat

Abstract: A mat comprising a base cloth (1) having a pile (2) tufted thereto. A rubber backing (4) applied to a non-pile surface (3) of the base cloth, a cotton-like layer (6) woven from a polyester textured yarn, non-adherent to the rubber and filaments (7) which are needle-punched through the woven layer. In this mat, weakly adherent regions (8) at which the woven cloth and the rubber portion contact each other and strong adhesive regions (9) at which the cotton-like layer and the rubber portion contact each other are formed in dots in a large distribution. Waving deformation during repeated use is prevented.

Description: This invention relates to dust mats which can prevent deformation. More specifically, it relates to dust mats for rental in which wavy phenomena on the mats surface are prevented even when it is used and regenerated for a long period of time. Heretofore, to prevent indoor entry of outdoor dusts from shoe soles, a dust controlling mat has been widely used. This dust-controlling mat is lent to the consumer for a certain period of time, and after being used as spread in a place where people move in and out, it is recovered and regenerated by washing and treated with oiling agent, etc. It is then again lent to the consumer on a rental basis. The rental mats, as disclosed in Japanese Publication No. 7450/84, are of the separate-type in which a mat having a pile is detachably applied to a rubber picture framelike base and the integral-type in which a rubber sheet is cemented to the back of a piled mat. The latter tends to be preferred for its outward appearance. Binding is strong and in usual use and washing, the product does not peel or get damaged. But within a relatively short period of rental cycle, waving occurs at the mat surface. This impairs the commercial value of the rental mat , reduces its safety and impairs its dust removing property. In a conventional integral mat, efforts are being made to strengthen the base cloth and the rubber sheet to prevent the peeling of the mat base and the rubber sheet and loss of the piles during long term use. Since the base cloth is very different from the rubber sheet in chemical composition and properties, during production, use and regeneration, a dimensional difference tends to form and this is liable to cause waving. For example, when a rubber sheet is heat-melted to a base cloth of the mat, the rubber sheet is already elongated by heat and the elongation formed by this heat reduces after production. A dimensional difference forms between the two, and waving occurs between them. Furthermore, since the rubber is non-shrinkable at the time of washing, the base cloth shrinks to develop a dimensional difference. Thus, likewise, waving also forms. This dimensional difference likewise occurs under conditions in which the mat is exposed to heat, light, steam or water. It is an aim of this invention to remove the above defects of the conventional integrated mat, and provide a rental integrated mat in which not only during production but also during use, washing or regeneration the occurrence of waving by dimensional changes is reduced. Another aim of the present invention is to provide a rental mat which can reduce the occurrence of waving during preparation, use and regenerating process without causing peeling of the base cloth of mat and rubber sheet or loss of the piles. According to this invention, there is provided a dust mat comprising a base cloth, a mat pile tufted to the base cloth, and a rubber backing applied to the opposite side of the base cloth from the mat pile, the base cloth being a composite of a woven cloth of a textured polyester yarn substantially non-adherent to the rubber backing and a second layer of filament-type or a spun-type fibres, the second layer being needle-punched through the woven cloth, the adhesive interface between the rubber backing and the composite having a distribution of weakly adhesive regions, at which the woven cloth and the rubber contact each other, and strongly adhesive regions at which needle-punched portions and the rubber contact each other. In the rental mat, a base cloth having piles and a rubber sheet are bonded together. One type uses a woven cloth of a polyester textured yarn, particularly a filament like yarn, non-adhesive to the rubber backing and a second layer of fibers of the filament-type or spun-type, the base cloth being a composite obtained by needle-punching the second layer through the woven cloth. For the textured yarn which is not adhesive to the rubber backing layer, there may be used an ordinary polyester yarn of the filament-type or spun-type. There may be a latex, or emulsion non-adhesive to the NBR of the backing layer which is adhesive to the yarn system, or a polyester film-like yarn having good deformability or stretchability and having low adhesiveness to the rubber backing layer. No secondary processing is required and since the fiber is filmy, invasion into the rubber is less and it therefore provides lower adhesion. From this point of view, a polyester film-like yarn is best. On the other hand, when a second layer, in which the fiber is of filament-type or spun-type, is needle-punched through the woven cloth, needle-punching is carried out easily, but also the second layer which is like cotton is bonded to the woven cloth in a markedly bulky condition. Our further report will follow shortly, once the filing details become available. Furthermore, since the needle-punched portions have a very high specific surface area, they adhere to the rubber firmly. With the invention, when a base cloth having piles tufted to it is heat-bonded to a rubber sheet, the adhesive surface between the rubber backing and the base cloth has the particular adhesive structure in which a weakly adhesive regions exist where the woven cloth portion contacts the rubber portion and strongly adhesive regions exist where the needle-punched portion contacts the rubber portion are formed indots in a large distribution. By this adhesive structure and the properties of the composite base cloth, a very tough adhesive structure is introduced between the mat pile-tufted base and cloth and the rubber sheet. When a dimensional difference arises owing to the cause mentioned above between the base cloth and the rubber sheet, peeling occurs between the woven cloth of a polyester textured yarn non-adhesive to the rubber backing and the rubber sheet thus reducing the dimensional difference and the occurrence of waving. The invention will further be understood from the following description, when taken with the attached drawings, which are given by way of example only, and in which: Figure 1 shows one example of the rental bonded mat of the invention. Figure 2 shows the sectional structure of the base cloth. Figure 3 shows the section of the adhesive surface between the base cloth and the backing. Figure 1 shows one example of the rental integrated mat composed of a base cloth 1, a mat pile 2 tufted to the base cloth 1 and a rubber backing 4 applied to the non-pile surface 3 of the base cloth. Figure 2 shows the sectional structure of the base cloth, which comprises a woven cloth 5 of a polyester textured yarn, especially film-like yarn, non-adhesive to the rubber, and a cotton-like layer 6 of the filament-type or spun-type, which is needle-punched 7 through the woven cloth. Figure 3 illustrates a section of the adhesive layer between the base cloth (1) and the rubber backing, in which weakly adhesive regions 8 at which the woven cloth 5 and the rubber portion 4 contact each other and strongly adhesive regions 9 at which the needle-punched portion 7 and the rubber portion 4 exist in dots in a large distribution in the adhesive surface between rubber backing 4 and the composite base sheet 1. Examples of the polyester film-like yarn constituting the woven cloth 5 are high-molecular-weight polyesters, especially polyethylene terephthalate, and thermoplastic copolyesters composed mainly of ethylene terephthalate, which are strongly stretched to increase tensile strength and cut to a certain width. This film like yarn may be somewhat fibrillated, but excessive fibrillation is not preferred. This film-like yarn generally preferably has a thickness of 10 to 5000 µm, and a width of 0.1 to 20 mm. As a textured yarn to be subjected to a non-tacking treatment, there may likewise be used high-molecular-weight thermoplastic polyesters, especially polyethylene terephthalate, or thermoplastic copolyesters composed mainly of ethylene terephthalate strongly stretched. The non-adhesive processing of these textured yarns may involve treatment with a paste such as a latex emulsion non-adhesive to NBR, for example, an acrylic acid ester emulsion, an ethylene acetate-type emulsion or PVA-type water-soluble resins in an amount of 5 % to 30% OWF. If the amount is less than 5 % OWF, the fiber cannot be entirely rendered non-tacky. When it is treated in an amount of more than 30 % OWF, the tufting , becomes difficult. When the unprocessed yarn is processed into a woven cloth and then treated , the same effect will be obtained. The woven texture of the woven cloth is not particularly limited, but it may satisfactorily be of a plain weave. If desired, it may be a twill weave or another such deformed weave. The unit weight of the base cloth may vary depending upon the weight of the mat, but generally it may be 30 to 500 g/cm² preferably. To facilitate needle punching, a lubricant may be included in the textured yarn of the woven cloth. Textured yarns such as a filmy yarn may be colored in a desired color of a desired shade. The second, cotton-like, layer is composed of the same fiber polyester mentioned above and composed of a web of the filament-type or spun-type. By overlaying at least one layer of the web on the woven cloth and by needle-punching it by a known means the woven cloth and the cotton-like layer can be integrated. This web is bulky, and even after needle-punching, its condition is maintained. The polyester fibers constituting the second, cotton-liked layer should preferably have a single yarn denier of generally 0.5 to 100 denier, especially 3 to 20 denier. The constituent single yarn may be a multi-filament or a staple. The second layer may also be a carding web, or a spun bonded web. The unit weight of the second layer is preferably 10 to 300 g/m². The density of needle punching is at least 1000/m² to maintain adhesiveness to the rubber, and from the viewpoint of punching operation efficiency, it is preferably 1000000/m² or more to maintain adhesion to the rubber. In the present invention, an ordinary textile fiber may be used as fibers constituting the cotton-like layer, and functional fibers such as water-absorbing fibers, oil-absorbent fibers, electroconductive fibers, anti-bacterial fibers, anti-mold fibers, de-odorizing fibers, and aromatic fibers to develop their own functions. For example, by using water-absorbent fibers in the cotton-like layer, although the piles applied later may not be water-absorbent, a water-absorbent property may be produced without changing the outer appearance. Examples of the pile yarns to be struck into the base cloth are cotton fibres, rayon fibers, polyvinyl alcohol fibers, acrylic fibers, nylon fibers, spun yarns composed of one or two or more other synthetic fibers, and multifilament yarns. Generally the tufted pile length is 3 to 20 mm. The type of the pile may be cut piles or loop piles. They may be crimped or uncrimped, and the pile length may be constant or different from each other. For example, they may be, for example, a high cut-low loop. The denier of the piles may be changed greatly and, for example, they may have a pile total denier of 500 to 1,000 denier. The pile striking condition may be those known per se. The stitch may be 4 to 20 per inch. The gauge may be 2 to 20 per inch. Examples of the rubber sheet as a backing may include various elastomers such as nitrile-butadiene rubber (NBR), styrene-butadiene rubber (SBR), chloroprene rubber (CR), polybutadiene (BR), polyisoprene (IIB), butyl rubber, natural rubber, ethylene-propylene rubber (EPR) ethylene-propylene-diene rubber (EPDM), polyurethane, chlorinated polyethylene, chlorinated polypropylene, and soft vinyl chloride resin. From the standpoint of oil resistance and weatherability, the nitrile-butadiene rubber (NBR) is preferred. In the formation of the rubber sheet, known additives, such as sulfur-type or organic vulcanizes, vulcanization accelerators, softening agents, antioxidants, fillers, dispersants, plasticizers and coloring agents may be added in known amounts. In the production of an integrated mat, the above rubber composition is kneaded by using a roll or a Banbury mixer; to mold the composition into a sheet it is laid over a tufted mat; and it is heated and pressed in a pressure mold and a known suction pressure-reduction mold to perform adhesion and vulcanization simultaneously. To increase adhesion of the rubber sheet to the base cloth, the non-pile surface of the base sheet may be coated with the same latex sheet as the rubber sheet, or may be coated in advance with an adhesive or an adhesion promotor such as ethylene-vinyl acetate. The unit weight of the rubber sheet may be in the range of 500 to 3000 g/m². The two may be integrated such that the end edge of the rubber sheet may somewhat go outside from the end edge of the base cloth. The vulcanization and adhesion may be carried out at a temperature of 120 to 185°C under a pressure of 0.5 to 10 kg/mm². The pile yarn of the mat of this invention adsorbs dusts adhering to the shoe soles and holds then. To increase this action further, a dust-adsorbent oil may be coated or impregnated in the pile yarns. Examples of the dust-adsorbent liquid are liquid paraffin, spinolle oil, alkylbenzene oil, diester oils, a mineral oil such as castor oil, synthesis oil, vegetable oils, and aqueous dust adsorbents described in Japanese Patent Publications No. 1019/1978 and No. 37471/1978. The amount of the adsorbent applied is generally 20 to 500 g/m². With the present invention by using as a base cloth a composite of a woven cloth of a polyester textured yarn, especially a filmy yarn, which non-tacky to the rubber, and a cotton-like layer formed from fibers of filament-type or spun-type needle-punched through the woven cloth, when the base cloth obtained by tufting the mat piles and the rubber sheet are bonded, a particular adhesive structure is formed on the adhesive surface between the rubber backing and the base cloth of the composite whereby weakly adhesive regions exist where the base cloth portion contacts the rubber portion and strongly adhesive regions,at which the needle-punched portion contacts the rubber portion ,are formed in dots in a large distribution. By this adhesive structure and the properties of the composite base cloth, a firm adhesive structure is introduced between the base cloth obtained by tufting mat piles and the rubber sheet, and when a dmensional difference occurs between the base cloth and the rubber sheet, peeling occurs between the woven cloth of the textured yarn and the rubber sheet to relieve the dimensional difference and waving deformation can be reduced. In the mat of this invention, the base cloth and the rubber are not wholly adhered to each other, but are adhered in evenly distributed dots. Hence, the suppleness of the mat can be ensured, and properties such as bending stiffness and winding stiffness do not easily show. Thus, the best properties of a rental mat are maintained, and the commercial value of the mat can be enchanced. Further since the mat has supplemess, a trouble of the mat moving on the floor surface on being trodden on is effectively removed. (Examples) Example 1 Pile BCF Nylon Stitch 6/inch Gauge 5/32 pile height 9 mm Unit Weight 880 g/m² cut pile Base Cloth (A) polyester plain weave Unit weight 200 g/m² (B) Polyester film yarn plain weave Unit weight 150 g/m² Second layer: Punching polyester filament yarn Unit weight 120 g/m² Single fiber denier 5 d Density 10000/m² Precoat NBR latex 200 g/m² (solids) Vulcanizing agent (sulfur) 1 % by weight incorporated A mat of the above materials was prepared and the pre-coat layer was dried at 150°C for 20 minutes. These mats A and B were cut to 70 x 85 cm and integrated mats were formed by the following procedure. On an unvulcanized NBR sheet having a thickness of 4 mm having vulcanizer (sulfur), 1 % by weight and a vulcanization promoter (2-mercapto benzothiazole), 1 % by weight, incorporated therein. The mat cut to the above-size and pressed at 150°C for 15 minutes under a pressure of 5 kg/cm² to form vulcanization and adhesion and to prepare nylon pile integrated mats A and B. These mats were laid for 3 days in a place having 3000 pedestrains/day, and the mats were washed and regenerated in a customary manner. This operation was repeated 20 times, and the pile retention strength and the base cloth-rubber adhesion strength were measured. The results are shown in Table 1. Table 1 also shows the degree of waving of the mat in terms of the waving height (mm) and the number before and after 20 cycles of mat washing and regeneration. The yarn pulling strength and the adhesion strength (between the base cloth the rubber) were carried out in accordance with the pile yarn pull strength and the peel strength of the liner in JIS L 1021. Example 2 Pile Vinylon 100 % Stitch 8.5/inch Gauge 1/8 Pile height 10 mm Unit weight 800 g/m² Base Cloth (C) Polyester plain weave Unit weight 120 g/cm² (D) Polyester film yarn plain weave Unit weight 150 g/m² Second layer: Punching-Polyester Spun yarn Unit weight 120 g/m² Single Yarn denier 3d Punching density 15000/m² Pre-coat NBR latex 60 g/m² (solids) Cross-linking agent Water-soluble melamine resin 3 % by weight The pre-coat layers of the above materials were dried at 150°C for 10 minutes in the same way as in Example 1 to prepare integrated mats C and D. The same test as in Example 1 was conducted on these mats to measure the pile retention strength. The results of the measurement are shown in Table 1. Example 3 Pile Acrylic fibers 100 % Stitch 8.5/inch Gauge 5/32 Pile height 10 mm Unit weight 700 g/m² Base Cloth (E) Polyester plain weave Unit weight 130 g/m² (F) Polyester film yarn plain weave Unit weight 130 g/m² Second layer: Punching-polyester filament yarn Unit weight 120 g/m² Single yarn denier 30 d Punching density 2000/m² Pre-coat None The above mentioned of the mats were preferred in the same way as in Example 1 to prepare mats E and F. The mats were tested as in Example 1 to measure the pile yarn retention strengths. The results are shown in Table 1. As shown in Examples 1 to 3, the adhesion strength between the original cloth and the rubber portion and the yarn pulling strength were good when any fibers were used, and the incidence of waving could be reduced.

Claims: A dust mat comprising a base cloth (1), a mat pile (2) tufted to the base cloth, and a rubber backing (4) applied to the side (3) of the base cloth opposite to the mat pile, the base cloth (1) being a composite of a woven cloth (5) of a textured polyester yarn substantially non-adherent to the rubber backing and a layer (6) of filament-type or a spun-type fibres, the said layer (6) being needle-punched through the woven cloth (5), the adhesive interface between the rubber backing (4) and the base cloth (1) having a distribution of weakly adhesive regions (8), at which the woven cloth and the rubber contact each other, and strongly adhesive (9) regions at which needle-punched portions (7) and the rubber (4) contact each other. A dust mat according to claim 1 wherein the original yarn of the woven cloth is a polyester film-like yarn. A dust mat according to claim 2 wherein the film-like yarn has a thickness of 10 to 5000 µm and a width of 0.1 to 20 mm. A dust mat according to claim 1 wherein the original yarn of the woven cloth is a thermoplastic, strongly stretched, polyester yarn treated to the extent of 5 to 30 % OWF with an emulsion or other agent so as to be non-adherent to the rubber. A dust mat according to any preceding claim wherein the base cloth has a weight of 30 to 500 g/m². A dust mat according to any preceding claim wherein the second layer is a carding web or spun-bonded web of a polyester fiber having a single yarn denier of 0.5 to 100 denier. A dust mat according to any preceding claim wherein the second layer has a weight of 10 to 300 g/m². A dust mat according to any preceding claim wherein the needle-punching is carried out at a density of 1000 to one million per m². A dust mat according to any preceding claim wherein the rubber backing is composed of nitrile-butadiene rubber.

Inventors: NAGAHAMA YUJI C O DUSKIN CO LT, SUMIMOTO KAZUSHI C O DUSKIN CO, NAGAHAMA, YUJI C/O DUSKIN CO., LTD., SUMIMOTO, KAZUSHI C/O DUSKIN CO., LTD.
Applicants: DUSKIN CO LTD, DUSKIN COMPANY LIMITED
Application year: 1991
Main classification: A47G27
IPC codes: A47L23, A47G27, D06N7