Polymer backed material with non-slip surface and method of making same

Abstract: Non-slip laminatable materials are provided by coating a polymer sheet backing with mineral particles adhered to the backing by a radiation curable adhesive.

Description: The present invention generally relates to materials with non-slip surfaces also referred to in the context of this case as coated abrasive materials or articles, and methods of forming such products. It is well known in the coated abrasive art to apply a resinous binder and abrasive grains to a paper or cloth backing material (the "backer") and then to cure the binder to produce a coated abrasive product. Typically, one or more overcoats (the "size" coats) are applied over the grain carrying layer (the "make" coat) and, in turn, cured. The use of radiation curing technology, e.g., electron beam technology, to fix abrasive grit to certain substrates such as paper and cloth is known in the art. Systems for commercially applying such radiation curing, e.g., electron beam curing technology, to the manufacture of coated abrasives are disclosed and explained in U.S. Patent Nos. 4,345,545 and 4,385,239. Electron beam curable resin systems applicable to the electron beam manufacture of coated abrasive products are also well known as disclosed and explained in U.S. Patent Nos. 4,457,766; 4,547,204; and 4,588,419. These patents teach the use of urethane oligomers as radiation curable resin systems, e.g., electron beam curable resins, in the fixing of abrasive grits to substrates such as webs (backers) of paper and cloth. The application of mineral particles to a polyvinyl chloride floor matting material is discussed in U.S. Patent No. 4,336,293. In this reference, a polyamide primer is applied to a silicone impregnated kraft release paper. Then a heat curable liquid polyurethane make resin is coated onto the polyamide primer. This composition is then partially thermally cured by running it through an oven at 120°C for 30 minutes. Once it is partially heat cured, the mineral particles are applied and a size coating, e.g., the same composition as the make coat, is spread on and the composite again run through an oven at 130°C for 4 hours to fully thermally cure it. In the formation of the composite, the polyamide "prime coating" is a "hot melt adhesive resin". The composite, still on the kraft release paper, is then concurrently fed, in sheet form, into an extruder along with hot, melted polyvinyl chloride (in liquid form) which adheres or bonds to the polyamide "prime coating" to glue the polyamide, as a hot melt adhesive, to the solidifying surface of the polyvinyl chloride which forms the backer. The kraft release paper is peeled off as the composite is laminated to polyvinyl chloride substrate material, the combination which then forms the floor matting. U.S. Patent 4,196,243 teaches the formation of a "plastic wear layer" on a polyvinyl chloride substrate having a thickness in the range of about 1.27-6.35 mm (50-250 mils. ). Ultraviolet light is used to cure the polyurethane make and size coatings which are used. The make and size resin systems must be modified by the addition of "photosensitizers" which are sensitive to the wave length and energy level of the ultraviolet light source that is being applied. U.S. Patent 4,608,287 shows the formation of an "abrasive" coating on a "plastified" polyvinyl chloride film of 0.05mm in thickness. The polyvinyl chloride film, itself, has a paper sheet adhered to its opposite surface by a pressure sensitive adhesive. A chalk extended polyoxypropylene glycol/diphenylmethane diisocyanate (polyurethane) resin system is applied to what is to be the "abrasive" coated side of the polyvinyl chloride backer. Granulated polyurethane, as the "abrasive" material, is then spread on top of the resin system, and the composite is put into a hot air drying oven at 80°c for 5 minutes "to accelerate cross-linking". A second example in this reference shows the use of a non-woven fabric layer backer bonded with an acrylic resin. On this fabric layer backer, a coating of heat curable "synthetic rubber based adhesive" is formed. Then, on this synthetic rubber layer, a diphenylmethane diisocyanate (70% aliphatic solvents) layer is formed, onto which is spread granulated polyurethane powder. This formed composite then is put into an oven at 80°C for 7 minutes to "cross-link" the resin by "evaporation of the solvents". Following this, a second coat of the polyurethane resin (this time with 30% aliphatic solvents) is spread on, and the composite is placed back into the oven at 80°C for another 7 minutes. This second resin layer is said to provide "an anti-dirt protective film" and to "increase the abrasive strength". In this second example, no polyvinyl chloride is used. Polyvinyl chloride has a relatively low softening point, thus rendering it unsuitable, as a backer material, for use in conventional thermal curing techniques for producing coated abrasive products. The radiation curing techniques, as explained in several of the above cited references, do not use the application of heat, per se , as the primary means for curing resins. Thus, the heat generated in the electron beam resin curing processes, although existent, does not reach the levels wherein polyvinyl chloride materials, especially in relatively unsupported thin sheet form, are rendered overly softened, melted or decomposed. The electron beam resin curing techniques are especially suitable for application to production of the products of the present invention. In particular, U.S. Patent Nos. 4,345,545; 4,385,239; 4,457,766; 4,547,204; and 4,588,419 show the relevant factors applicable to the electron beam formation of coated abrasives and variants thereof. From US-A-4 642 126 coated abrasive is known having at least one layer of adhesive comprising the cured product of liquids containing chemical unsaturation and capable of rapid, spontaneous polymerization initiated by actinic radiation, said cured adhesive being sufficiently deformable at a first temperature of not more than 130°C. to be shaped, along with the backing on which it is coated, into a predetermined curvature by the application of tensile forces less than those required to break the coated abrasive, said cured adhesive further being sufficiently rigid at a second temperature not less than 25°C. so as to cause said coated abrasive to retain at said second temperature, in the absence of mechanical forces other than those induced by natural gravity, the curvature imparted to said coated abrasive at said first temperature and maintained during cooling from said first temperature to said second temperature. WO-A-90/11870 describes a flexible abrasive article for cleaning, polishing or smoothing objects which is resistant to absorption of liquid and capable of conforming to the shape of the object. The article comprises a flexible resilient closed cell polyvinyl chloride foam substrate having upper and lower surfaces with a reinforcing textile layer and abrasive particulate matter adhered to at least one surface. The reinforcing textile layer may be buried within the foam substrate with abrasive particulate adhered to one or both surfaces of the substrate; or the textile layer may be adhered to one surface and the particulate matter adhered to the other. In addition, the article may be laminated to a thermoformable rigid sheet to produce shaped tools. GB-A-2 087 263 discloses resin compositions which are particularly suitable for utilization in electron cured coated abrasives. The resin systems of the instant invention have been devised to be particularly suitable for the backing fill of a cloth which is to form the base of a coated abrasive. The formation of a treated base cloth for coated abrasive formation by electron beam curing resins creates a product which in addition to being suitable for immediate formation into a coated abrasive by application of grain is further a product which may be stored for later use or sold to other parties that have need for a waterproof stretch-resistant cloth or that make coated abrasives without doing cloth finishing. The invention also encompasses the formation of electron curing resin systems which are particularly desirable for the make coat and size coat utilized in forming coated abrasives. It is within the system of the invention to utilize the electron radiation curing resins in combination with the conventional heat curing resins. These and other features, aspects and details of the present invention can be more readily comprehended from the independent claims 1 and 12, the dependent claims, the following text of the specification, the example and by reading the cited references. The invention provides polymer, e.g. polyvinyl chloride backed products with non-slip surfaces also referred to as coated abrasive products and methods of making such products. In this context it is to be understood that the term coated abrasive material or product is not used in the sense of a material or product suitable for abrading or grinding a surface but rather in the sense of a material which has a rough non-slip surface. The products of the present invention comprise a polymer backing material and, adhered to the surface of the backing by a radiation-curable adhesive, mineral particles so as to provide a non-slip surface. The products of the present invention will, in many cases (but not, necessarily, always), be laminated or bonded to other substrates of natural and synthetic materials, e.g., wood, concrete, metal, polyurethanes, polyethylenes, polyesters, isoprenes, synthetic and natural rubbers, etc., in particular, other substrates preferably of polyvinyl chloride material. Some of these other substrates may have relatively complex surface configurations, e.g., extruded, polyvinyl chloride floor matting materials. Thus, the products of the present invention must, in many cases, be severely deformed or "shaped" to permit substantially the full surface areas thereof to come into substantial surface-to-surface, or face-to-face contact with those complex surface configurations of such other substrates, to enable such lamination or bonding, substantially at all points of contact, therebetween. It is also highly preferred that the materials selected should be thermoformable as a unit without decomposition of any of the components or delamination by failure of the bond between the backer material and the resin bonding the mineral particles to the backer material. To ensure the capability of deformation or "shaping", it is also important for the products of the present invention to be able to flex to a significant degree. For other applications, the products of the present invention may be used directly; i.e., without being bonded to a substrate; in such applications the backer, per se , also usually functions as the substrate. In practice, therefore, to permit such bonding, flexing and/or thermoforming, it is preferred that several of the physical properties of the resin system(s), used to bond the mineral or abrasive particles of the present invention to the backer be as closely matched as possible to the backer which is used. Examples of such physical properties, which are deemed important to be substantially matched, include flexibility, stretchability, yield, tensile, elongation, deformation, rate of softening, melt point, etc. Thus, it is considered a key feature of the present invention that the resin systems, described hereinafter, when applied as hereinafter described, and when radiation cured, preferably electron beam cured, have such physical properties, particularly in regard to flexibility, that when bonded to the backer which is used, e.g., the preferred polyvinyl chloride backer sheet or film materials preferably in the range of 152.4 µm (6 mils) or less in thickness, the tensile strength of the product of the present invention is equivalent to or greater than that of the backer which is used, and the elongation potential of such product of the present invention is not less than 25% of that original backer material but with that product of the present invention still capable of being stretched (elongated) in any given direction, without tearing, to a dimension which is at least 110% and preferably 125% of the corresponding unstretched (unelongated) dimension; this ensures sufficient flexibility for the deformation and "shaping" as discussed above. The present invention is not, however, limited to application to backer materials which are 152.4 µm (6 mils) or less in thickness. The resin system(s) of the present invention, in addition, has (have) relatively unique physical properties not apparent in many backer materials, e.g., the preferred polyvinyl chloride, e.g., such physical properties as the capability of readily bonding to the mineral particles e.g. abrasive grain particles, of the present invention, the capability of holding those particles securely in place while physical forces are applied thereto in use and the capability of complimenting the flexibility properties of those backer materials. Finally, the resin system(s) of the present invention is (are) designed to be substantially at least as resistant to chemical attack (corrosion) as the selected backer material, e.g., polyvinyl chloride backer, and to exhibit substantially at least an equivalent degree of durability in comparison to the selected backer material, e.g., polyvinyl chloride backer material. It is, of course, highly desirable that it is thermoformable under conditions in which the backer material can be thermoformed. Mineral particles, or abrasive mineral grit material, e.g., aluminum oxide, silicon carbide, fumed silica and silica gel, preferably in the form of standard grain size particles, preferably within the range of about 50 grit to about 220 grit, in size, are bonded to the preferred polyvinyl chloride backer material by way of one or more radiation curable, preferably electron beam curable, urethane oligomer resin systems. Preferably, two or more different grades of polyester urethane acrylate resins are blended and mixed together with a combination of ethoxyethoxyethyl acrylate and N-vinyl-2-pyrrolidone monomer diluent materials, in a ratio which renders the resin system radiation curable, preferably electron beam curable, and which, upon curing, produces a resinous film, bonded to a backer material selected from the group consisting of polyvinyl chloride, polyethylene, polyurethane, polyethylene terephthalate (polyester), polypropylene, polyamide, polysulfide, polystyrene, polyvinyl acetate, polybutadiene, styrene-butadiene, acrylonitrile-butadiene, acryolnitrile-styrene copolymer, acrylonitrile-butadiene-styrene copolymer and vinylidene chloride. The resin system is initially applied as a make coat to the selected backer, preferably a polyvinyl chloride backer, by conventional means. Following this, the particles are distributed onto the maker coat, usually in a uniform density and thickness, also by conventional means. Alternatively, the mineral particles, e.g. abrasive grits may be blended into the resin system being used, to form a slurry; the slurry containing the mineral particles is then applied as such to the selected backer. Then preferably the make coat system (or the resin system which is part of the slurry, as the case may be) is electron beam cured, although this step is optional as the preferred electron beam curing techniques, or other radiation curing techniques, may alternatively be accomplished in a single step, after the size coat, explained hereinafter, has been applied. Following the application of the make coat, and, if desired, the preferred electron beam (or other radiation) curing thereof, a size coat, either of the same resin system as used for the maker coat, or of another resin system with like or complimentary properties in relation to the maker coat, is applied over the distributed mineral particles, likewise, by conventional means. Then the one or more resin systems of the present invention are radiation cured, preferably electron beam cured in the manner described, e.g., in US- patent Nos. 4 345 545, 4 385 239, 4 457 766 and 4 588 419. Thus, both the one or more resins systems, with the mineral particles embedded therein and bonded thereon and/or thereto, are bonded, in turn, to the selected backer, preferably a polyvinyl chloride backer, to form a product of the present invention. A preferred resin system, within the scope of the present invention, which is electron beam curable, is formed by mixing N-vinyl-2-pyrrolidone monomer, in a stabilized form, preferably with an equal portion, by weight, of ethoxyethoxyethyl acrylate, at a temperature in the range of room temperature to about 43.5°C (about 110°F), preferably 32.2°C to 37.8°C (90°F to 100°F), more preferably 35°C (95°F). Then at least two differing grades of polyester urethane acrylate resin are prepared for blending into the foregoing mixture by melting them to the point of ready flowability, preferably at 68.3°C to 73.9°C (155°F to 165°F), more preferably 71.1°C (160°F), for a period of time sufficient to produce such flowability, preferably for a period of 22 to 26 hours, more preferably 24 hours. In sequence, the first of such preferred polyester urethane acrylate resin grades, followed by the second of such preferred grades, are preferably blended in the mixture of stabilized N-vinyl-2-pyrrolidone and ethoxyethoxyethyl acrylate, with such mixture being maintained preferably at a temperature within the range of 32.2°C to 37.8°C (90°F to 100°F), and with the preferred total final mixture of ingredients including 14 to 15 weight percent of stabilized N-vinyl-2-pyrrolidone, 14 to 15 weight percent of ethoxyethoxyethyl acrylate, 34.5 to 35.5 weight percent of the first of such polyester urethane acrylate resin grades and 34.5 to 35.5 weight percent of the second of such resin grades. Optionally, preferably up to 0.06 weight percent of fluorocarbon surfactant, for example, FC-171, a product of the Minnesota Mining and Manufacturing Company of St. Paul, Minnesota, U.S.A., may be added as a wetting agent, more preferably 0.04 weight percent. It is notable that preferably no fillers, pigments (or other coloring agents) or suspending agents are used in the resin systems of the present invention, although one or more fillers, pigments, other coloring agents and/or suspending agents may be used if desired; however, such must be carefully selected so as not to impede, or otherwise interfere with, the radiation curing technique which is to be applied (such additions do not create significant problem if the preferred electron beam curing is used). The mixture is mixed, preferably agitated, preferably at a slow speed, preferably accompanied by short, intermittent bursts of medium to high speed mixing, preferably agitation, until thoroughly mixed and uniformly blended, and until the temperature of the mixture is stabilized within the range of 15.5°C to 48.9°C (60°F to 120°F), preferably within the range of 32.2°C to 37.8°C (90°F to 100°F), throughout. Thus, a radiation curable resin system, e.g., an electron beam curable resin system, is produced within the scope of the present invention. The preferred polyvinyl chloride backed coated non-slip or coated abrasive product of the present invention may be bonded to, for example, a polyvinyl chloride substrate, e.g., sheet or film material, by co-extrusion, whereby the product of the present invention is linearly extruded, preferably through a conventional extrusion die, along with a selected substrate material, preferably polyvinyl chloride, by conventional extrusion methods and using conventional extrusion equipment, to produce, for example, a floor mat with the product of the present invention bonded to the surface thereof. The product of the present invention is, preferably, laminated and bonded to a selected substrate, e.g., a polyvinyl chloride solid article, which may or may not be heat pre-softened, by the application of heat and pressure, by methods which are well known to those with skill in the art; alternatively the surface of the polyvinyl chloride or other substrate material may be rendered molten by the application of heat and/or pressure. Further, adhesive materials, as are conventionally used to bond together polymer materials, e.g., to bond polyvinyl chloride together, or to bond polyvinyl chloride or other polymers to dissimilar polymers or to other materials, may likewise be utilized where such backers and/or substrates are used. Although the most preferred backer material of the present invention is polyvinyl chloride, the backer material is selected from the group consisting of polyvinyl chloride, polyethylene, polyurethane, polyethylene terephthalate (polyester), polypropylene, polyamide, polysulfide, polystyrene, polyvinyl acetate, polybutadiene, acrylonitrile-butadiene, acrylonitrile-butadiene-styrene copolymer, styrene-butadiene, acrylonitrile-styrene copolymer and vinylidene chloride, with the more preferred backer materials being polyurethane, polyethylene, polyester, polyamide, polypropylene and polysulfide. These and other features of the present invention may be better understood from a reading of the following specification text and the appended claims. The polymer backed non-slip or abrasive products, of the present invention, may be prepared by coating preferably a polyvinyl chloride backer material with inorganic mineral particles such as inorganic abrasive grit. The preferred polyvinyl chloride material may be any commercially available polyvinyl chloride, but preferably is sheeting or film, and should be preferably of a thickness which will enable sufficient structural integrity for handling, but which is also sufficiently flexible and pliable to be continuously fed through radiation curing equipment, e.g., electron beam curing equipment, adapted to produce non-slip sheet products or coated abrasive products. The preferred polyvinyl chloride backing material, preferably sheet or film, is preferably about 254 µm (about 10 mils) or less in thickness, more preferably about 152 µm (about 6 mils) or less in thickness, although the present invention is not limited to applications wherein the polyvinyl chloride backing, or other backing material, is 254 µm (10 mils) or less in thickness. A variety of mineral particles or inorganic abrasive grit particles may be employed which will provide adequate frictional contact in use to prevent, or aid in the prevention of, slippage or skidding. Examples of suitable mineral particles are aluminum oxide, silicon carbide, fumed silica and silica gel; other mineral materials which are adaptable to radiation curing, in particular electron beam curing, may also be utilized. A maker and size coating comprising at least one resin system which is radiation curable, preferably electron beam curable, and provides a durable size coating for the intended use of the product is utilized. A maker coat is the resin coat onto which the particles are deposited. A size coat is the coat which is placed over the particles to aid in holding them onto the substrate during flexing and wear applications, usually in combination with some form of pressure or other applied physical force. A second size coat, sometimes referred to as an "over" or "super size" coat, may also be applied, if desired, although in many cases this is not necessary. The amount of the maker and size coats applied are whatever is sufficient to adequately hold and secure the particles to the polyvinyl chloride substrate, of the present invention, in subsequent use, i.e., as a stand-alone product or by bonding and/or lamination to some other substrate, and in final application, e.g., a floor or a floor mat surface, a hand tool grip or other non-slip applications, as are well known to those skilled in the art. The methods of applying the coatings of the present invention may be selected from those which are conventionally used with the electron beam curing methods of forming coated abrasive products. Among typical methods, for examples, are knife coating, roll pressure coating, transfer roll coating and doctor blade coating. The preferred method of coating used for the present invention is pressure roll coating. The resin system is chosen to match, in its preferred electron beam cured form, certain physical properties of the preferred polyvinyl chloride backer. The properties of the resin systems which are deemed to be significant are those described above, i.e., such as flexibility, stretchability, yield, tensile, elongation, deformability, rate of softening, melt point, corrosion resistance, durability, capability of securely bonding to both the mineral particles and the preferred polyvinyl chloride backer of the present invention and, of course, the capability of being readily radiation cured, preferably electron beam cured, as applied to a preferred polyvinyl chloride backer. It is quite important to ensure that the physical properties of the preferred electron beam cured resin system(s), bonded to both the preferred polyvinyl chloride backer and to the mineral particles, is (are) capable of being deformed and bonded and/or laminated, in unison with the preferred polyvinyl chloride backer of the present invention, to substrates, either of polyvinyl chloride material or otherwise. To ensure this, it is important that the flexibility of the resin system(s) is (are) generally complimentary to that of the backer material being used. A resin system (or systems) which is (or are) deemed complimentary, within the scope of the present invention, is one (or more) which produces a linear tensile strength, in the product of the present invention, which is at least as great as that of the backer used, and which reduces (or reduce) the elongation potential of the product of the present invention to no less than 25% of that of the backer material, as such, which is being used, but in no case produces an elongation capability of less than 125% of the original dimension of that product, in any given direction, on stretching, before tearing. In particular, in the preferred embodiment of the present invention, it is important that the resin system(s), in its (their) preferred electron beam cured form, is (are) capable of a bonding strength, in respect to both the preferred polyvinyl chloride backer and the mineral particles of the present invention, which is at least as great as the bonding and/of lamination strength between the preferred polyvinyl chloride backer of the present invention and the substrates to which that polyvinyl chloride substrate is to be bonded, as the case may be. The preferred resin system or systems to be used is (are) a unique combination of resin components, made from commercially available resins, with diluents and other components, which are notable for their ability to be blended together. More specifically, the resin system(s) preferably comprise a blend of two or more grades of urethane oligomers, both of which are polyester urethane acrylates, and these are further blended with a combination of ethoxyethoxyethyl acrylate and stabilized N-vinyl-2-pyrrolidone monomers, this latter combination being radiation curable and comprising a diluent. In addition, one or more surfactants, preferably containing fluorocarbon material, may be added as wetting agents. Diluents are added to adjust the viscosity of the coating mixture, adjusting that viscosity, and the sag resistance of the resin system(s), to best suit the application method thereof, such as, e.g., knife coating, roll pressure coating, transfer roll coating or doctor blade coating, techniques which are well known to those skilled in the art of making coated abrasive products. Further, the diluents may be used to modify the radiation curing properties of the resin system(s) and the flexibility of both the radiation, e.g., electron beam, cured resin system(s) and of the products of the present invention. Among suitable diluents for the electron beam curable resins are the vinyl pyrrolidones and the multifunctional and mono-functional acrylates, including, but not limited to, N-vinyl-2-pyrrolidone; 1,6 hexanediol diacrylate; tetraethylene glycol diacrylate; and trimethylolpropane triacrylate. The preferred diluent material is N-vinyl-2-pyrrolidone monomer, in a stabilized form. These materials, in addition to adjusting viscosity, tend to modify flexibility and reduce the energy level of the preferred electron beam radiation energy required for curing. The preferred product of the present invention, in the form of an electron beam cured coated adhesive with mineral particles on a polyvinyl chloride backer, may be readily co-extruded with a polyvinyl chloride compound, as normally used to form floor mating material, as that compound is being formed into floor mating; the standard floor mating then acts as a substrate, having the same composition as the grit coated polyvinyl chloride backer. Alternatively, the application of sufficient heat and pressure can be utilized to laminate the two together. Once in a formed state the mineral particles should remain thoroughly secured in and to the stretched film. Furthermore, the product is tough and flexible enough to offer good slip-resistance, skid-resistance and durability, in the form of wear-resistance, to heavy pedestrian traffic normally encountered in restaurants, kitchens, service stations, checkout counters and the like. The following example illustrates the preferred embodiment and best presently known mode of the present invention and is in no way intended to be limiting. EXAMPLE Two different grades of polyester urethane acrylate resin were used in forming the preferred resin system of the present invention, the first being Uvithane® UV-782 and the second being Uvithane® UV-783, both as supplied by Morton Thiokol, Inc., Morton Chemical Division, of Moss Point, Mississippi, U.S.A. The UV-782 resin grade, having CAS Number 64060-30-6. The UV-783 resin grade, having CAS Number 64060-31-7. Both of these resin grades, in their respective shipping containers, were placed into an oven at 71.1°C (160°F) and held at that temperature for 24 hours to preheat them. Concurrent with the latter period of the preheating of the two grades of polyester urethane acrylate resin, a mixing and blending kettle was preheated with hot water to 32.2°C (90°F), in a manner and using equipment common to the coated abrasive manufacturing industry. Initially added to the kettle, at 32.2°C (90°F), was 87.1 kg (192 lbs.) of stabilized N-vinyl-2-pyrrolidone monomer, specifically V-Pyrol®/RC as supplied by GAF Corporation of New York, New York, U.S.A., having CAS Number 88-12-0, and containing at least 98.5 weight percent of C₆H₉NO (iodimetric) with a molecular weight of 111.16. While holding the stabilized N-vinyl-2-pyrrolidone monomer in the kettle at 32.2°C (90°F), 87.1kg (192 lbs) of ethoxyethoxyethyl acrylate was added, mixed, and blended into that N-vinyl-2-pyrrolidone monomer. Specifically RC-20 ethoxyethoxyethyl acrylate was used, being supplied by the same source as the UV-782 and UV-783. The RC-20 bears CAS Number 7328-17-8 and with essentially the formula C₉H₁₆N₄. Care was taken in adding the RC-20 material to the V-Pyrol®/RC in the kettle to ensure that the mix temperature did not drift below 29.5°C (85°F). After the RC-20 and the V-Pyrol®/RC were thoroughly mixed and blended together, and the temperature was stabilized at 32.2°C (90°F), 204.1 kg (450 lbs.) of UV-782, at a temperature of 71.1°C (160°F), were added, being mixed in and blended in such a manner that the kettle contents temperature did not exceed 35°C (95°F). Then, likewise, 204.1 kg (450 lbs.) of UV-783, also at a temperature of 71.1 °C (160°F), were added, being mixed in and blended in such a manner that the kettle contents temperature did not exceed 35°C (95°F). Finally, 1.36 kg (3 lbs.) of fluorocarbon surfactant, namely FC-171, were added in, mixed and blended, and the temperature of the batch in the kettle was stabilized at 32.2°C (90°F). The mixing and blending were accomplished using a variation of mixer speeds, as is quite common in the art, and the batch mixture was circulated into and out of the kettle to further assure fully mixed and blended uniformity and a stabilized uniform batch temperature, also as is quite common in the art. Thus, the preferred resin system was formulated and prepared. In the Example described herein, the preferred resin system was applied to the dull side of 152.4 µm (6 mil) thickness polyvinyl chloride film, 101.6 cm (40 inches) wide, weighing the equivalent of 0.203 kg/m² (13.7 lbs./ream), and processed through the electron beam curing equipment, in accord with the equipment and procedures specified in the above published references using a radiation energy range of 1 to 10 MRAD, preferably 3 MRAD (used for the present Example), within a range of 250 to 325 KV, preferably at 285 KV (used for the present Example), in an inerting atmosphere of nitrogen, having an oxygen content of less than 2000 PPM. The polyvinyl chloride film used in the present Example was Product No. 39-44-0001-00-4, Vinyl Film, as supplied by RJF International Corporation (formerly The B.F.Goodrich Company, Engineered Products Group), Akron, Ohio, U.S.A. The application of the resin, in the Example, to the 152.4 µm (6 mil) thickness polyvinyl chloride film was accomplished by use of a standard transfer roll coating system for both the make and the size coats; the make coat and size coat were both identical, being of the preferred resin system as described above. The weight of the electron beam cured end product of the Example was the equivalent of 0.644 kg/m² (43.5 lbs./ream), ± 0.059 kg/m² (± 4.0 lbs./ream). The mineral particles used were standard aluminum oxide grits, having a standard grit size of 100. The applied grit may be within the weight range of about 0.148 to 0.37 kg/m² (about 10 to 25 lbs./ream), and in the present Example, comprised the overall preferred equivalent weight of 0.296 kg/m² (20.0 lbs./ream), ± 0.0296 kg/m² (± 2.0 lbs./ream), while the overall weight of electron beam cured resin in the final product may be within the range of about 0.059 to 0.074 kg/m² (about 4 to 5 lbs./ream), and in the present Example comprised the preferred equivalent of 0.155 kg/m² (10.5 lbs./ream), ± 0.0148 kg/m² (± 1.0 lbs./ream). The finished non-slip sheet product was bonded to an otherwise standard ribbed polyvinyl chloride floor mat material, as produced by RJF International Corporation of Akron, Ohio, U.S.A. under the Keroseal® trademark, by co-extrusion during the otherwise normal production of that floor mat material. The bonded floor mat material exhibited excellent bonding between the product of the present invention and the floor mat material, without use of any separate bonding agents or adhesives. The finished product of the instant Example was tested for tensile strength and elongation by an Instron® tensile tester, using a sample size of 2.54 cm x 20.32 cm (1" x 8") with a 15.24 cm (6") gauge length, a cross-head speed of 2.54 cm (1") per minute and a chart speed of 1.27 cm (1/2") per minute (full chart scale = 9.07 kg (20 lbs)). The results of those substantially all of the particles remained firmly bonded to the test pieces after being subjected to the foregoing tensile and elongation tests. As a general proposition for the products of the present invention, the tensile strength, in kg/cm (lbs./linear inch), should be at least as great as that exhibited by the particular backer material used, as measured in its uncoated state. Also, as a general proposition for the non-slip product of the present invention, the elongation, in cm (inches), is not less than 25% of that which is exhibited by the particular backer material used, as measured in its uncoated state, however, at the same time, the product of the present invention is capable of being linearly stretched (elongated), in any given direction, to a dimension which is at least 110% preferably at least 125 %, of the original unstretched (unelongated) dimension, in that same direction, before tearing occurs. Observation has indicated that the limitations of the foregoing general propositions are necessary to ensure the desired physical properties, in particular, flexibility, as discussed above, of the non-slip sheet product of the present invention. Because the sheet material of the invention is thermoformable, the thermal softening and decomposition temperatures of the backing and the radiation curable urethane polymer used to bond the particles to the backing should be such as to permit thermoforming of the finished sheet product and lamination to a desired substrate. The preferred embodiment of the product of the present invention has been carefully examined in comparison to the virgin 152.4 µm (6 mil) thick polyvinyl chloride sheet on which it is preferably formed, and both were noted to exhibit the desired physical properties as set forth and discussed above. In use, the preferred embodiment of the non-slip product of the present invention, as bonded to a standard ribbed polyvinyl chloride floor mat material, appears to exhibit good wear characteristics as well as providing relatively outstanding resistance to slipping and skidding.

Claims: A polymer backed non-slip sheet article comprising a polymer backer of a material selected from the group consisting of polyvinyl chloride, polyethylene, polyurethane, polyethylene terephthalate (polyester), polypropylene, polyamide, polysulfide, polystyrene, polyvinyl acetate, polybutadiene, styrene-butadiene, acrylonitrile-butadiene, acrylonitrile-styrene copolymer, acrylonitrile-butadiene-styrene copolymer and vinylidene chloride, said backer material having resin-bonded thereto mineral particles, said resin, which effects said resin bonding, being radiation cured from at least one radiation curable urethane oligomer resin system comprising a blended mixture of at least one grade of polyester urethane acrylate resin and a combination of ethoxyethoxyethyl acrylate and N-vinyl-2-pyrrolidone monomer; the backer material and the resin bonding materials being selected such that: a. the non-slip sheet material can be thermoformed without decomposition or delamination of the components; b. the tensile strength of the sheet material is at least as great as that of the backing material; and c. the sheet material has an elongation potential that is at least 25% of that of the uncoated backer material and the sheet material being capable of being stretched in any given direction, without tearing, to a dimension which is at least 110%, preferably 125%, of the corresponding unstretched dimension. The non-slip sheet article of claim 1 wherein said polymer backer material is selected from the group consisting of polyvinyl chloride, polyurethane, polyethylene, polyester, polyamide, polypropylene and polysulfide. The non-slip sheet article of claim 1 or 2 wherein said resin is electron beam cured from said at least one urethane oligomer resin system which is electron beam curable. The non-slip sheet article of one of the preceding claims wherein said mineral particles are selected from the group consisting of aluminum oxide, silicon carbide, fumed silica and silica gel. The non-slip article according to one of the preceding claims wherein said polymeric backing has from 0.1477 to 0.369 kg/m² (10 to 25 lb./ream) of a mineral particulate material bonded thereto by from 0.059 to 0.222 kg/m² (4 to 15 lbs./ream) of radiation cured polyurethane binder material. The non-slip sheet article of one of the preceding claims wherein said elongation capability (before tearing occurs) is at least 30% of that of said polymeric backing, and said elongation capability (before tearing occurs) is at least 140% in any given direction, of the unelongated dimension in that same direction. The non-slip sheet article of one of the preceding claims wherein said elongation capability (before tearing occurs) is at least 40% of that of said polymeric backing, and said elongation capability (before tearing occurs) is at least 150% in any given direction, of the unelongated dimension in that same direction. The non-slip sheet article of one of claims 5 to 7 which comprises from 0.222 to 0.369 kg/m² (15 to 25 lb./ream) of said mineral particulate material. The non-slip sheet article of one of claims 5 to 8 which comprises from 0.118 to 0.177 kg/m² (8 to 12 lb./ream) of radiation cured polyurethane binder material. The non-slip sheet article of one of claims 5 to 9 wherein said radiation cured polyurethane binder materials is electron beam cured binder material. The non-slip sheet article of one of claims 5 to 10 wherein said polymeric backing of material is selected from the group consisting of polyvinyl chloride, polyurethane, polyethylene, polyester, polyamide, polypropylene and polysulfide. A method of producing a polymer backed coated non-slip sheet article comprising: a. selecting a backer material from the group consisting of polyvinyl chloride, polyethylene, polyurethane, polyethylene terephthalate (polyester), polypropylene, polyamide, polysulfide, polystyrene, polyvinyl acetate, polybutadiene, styrene-butadiene, acrylonitrile-butadiene, acrylonitrile-styrene copolymer, acrylonitrile-butadiene-styrene copolymer and vinylidene chloride; b. applying at least one coating of at least one radiation curable urethane oligomer resin system onto a surface of said backer material; c. applying mineral particles to said backer material and said urethane oligomer resin system coated onto said backer material; and d. radiation curing said urethane oligomer resin system to bond said mineral particles to said backer material and the resin bonding materials being selected as in one of claims 1 to 4, wherein the sheet material has an elongation potential that is at least 25% of that of the uncoated backer material and the sheet material being capable of being stretched in any given direction, without tearing, to a dimension which is at least 110%, preferably 125%, of the corresponding unstretched dimension. The method of claim 12 wherein said mineral particles are blended into said resin system before said resin system is applied to said backer material, with said mineral particles and said resin system first being combined to form a slurry, with said slurry then being applied to said backer material, thus combining steps b. and c. of claim 12. The method of claim 12 or 13 wherein said polymer backer material is selected from the group consisting of polyvinyl chloride, polyurethane, polyethylene, polyester, polyamide, polypropylene and polysulfide. The method of one of claims 12 to 14 wherein said resin is electron beam cured from said at least one urethane oligomer resin system which is electron beam curable. The method of one of claims 12 to 15 wherein said mineral particles are selected from the group consisting of aluminum oxide, silicon carbide, fumed silica and silica gel. The method of claim 12 comprising the further step of thermoforming the non-slip sheet material to a desired configuration.

Inventors: WILLIAMS DAVID E, WILLIAMS, DAVID E.
Applicants: NORTON CO, NORTON COMPANY
Application year: 1992
Main classification: B24D3
IPC codes: B32B27, B29C70, B24D3, B32B7