Non-staining lubrication of laundry iron soles

Abstract: A laundry iron lubricating means is provided comprising a fabric substrate having a coating containing a lubrication agent. In the operation of the device, the hot laundry iron is run over the coated fabric with normal pressure. The lubrication provided by a single pass reduces iron drag by 20 to 50%, adequate for the ironing of at least one large garment without need for a second pass. The greater the sole temperature of the iron, the greater the drag reduction.

Description: The art of smoothing washed fabrics by means of a gliding pressure placed thereon by a hot metal surface is an extremely ancient one. Modern technology has affected both the means for heating the irons as well as providing a smooth bottom surface or "sole" which contacts the fabric to be smoothed. Notwithstanding these improvements a substantial amount of friction inevitably arises during the ironing process, which increases the labor which must be put into this somewhat tiresome bit necessary domestic process. It was, therefore, desirable to find a mode of applying a lubricating film to the sole of the iron in order to reduce the friction. Such a lubricating film, must be devoid of any possibility of transferring either odor or discoloration to the garments to be smoothed. From FR-A-1 158 328 it is known to apply a product in the form of a silicone derivative to the sole of a laundry iron which product prevents the sole from sticking to the fabric to be smoothed. Such product is not directly applied to the sole, but the sole is, prior to ironing, passed over the surface of an absorbant support impregnated with the said product. It has now been found that when the sole of a hot laundry iron is first passed over a silicone elastomer surface, the frictional drag in the subsequent smoothing process using such an iron is reduced depending on the temperature: The higher the temperature of the iron, the greater the reduction of drag. It is believed that the heat of the iron causes a very small but nevertheless significant amount of depolymerization of the elastomer, releasing sufficient silicone monomer or oligomer to provide a friction reducing coating on the iron sole. The effect may also be due to exceedingly small quantities of relatively low molecular weight silicone oils, normally present in commercial quality silicone elastomers. Thus, the silicone elastomeric coating is believed to act as a reservoir releasing silicone oil, monomers, or oligomers on demand as the hot iron is drawn across the surface. It has been found that other coatings may be formulated to act in a similar manner. Resin matrices such as acrylic polymers containing a relatively high melting point wax, suitably above 40° preferably above 60°C, such as carnauba wax may be formulated to release the wax to the soleplate, imparting a low friction surface to the soleplate of an iron under heat. The resin matrices may comprise a variety of polymers and lubricating agents. There may be employed polyvinyl acetate, polyvinyl chloride, poly(styrene/ acrylic), poly(styrene/butadiene), polyurethane, epoxy resins and similar polymers. The polymers are formulated with suitable lubricating agents which may include fatty acids, silicone oils and high melting waxes to release the agent to the soleplate, imparting a low friction surface to the soleplate of an iron under heat. Silicone elastomers and acrylic polymers containing carnauba wax, however give superior results. A laundry iron lubricating fabric is provided, comprising, suitably, a fabric substrate having a coating containing a lubricating agent, preferably a silicone elastomer, deposited thereon. Suitably, the fabric is a woven or non woven fabric which may be woven from monofilament threads or from natural or synthetic polyfilamentous fibre threads. The device operates which greatest efficiency when the maximum surface area of the elastomer can actually contact the sole of the laundry iron, thus adsorption on the surface of the threads rather than in the interstices of the filaments is required. It is, therefore, an object of the invention to provide a fabric having a lubricating coating deposited thereon which coating does not substantially penetrate into the fabric. According to one embodiment of the invention there is provided a laundry iron lubricating fabric having a coating selected from the group consisting of silicone elastomers and resin matrices containing lubricating agents deposited on the surface thereof, which fabric is characterised in that it has been pretreated with a surface sealant or pre-coated therewith. According to a second embodiment of the invention there is provided a laundry iron lubricating fabric having a coating selected from the group consisting of silicone elastomers and resin matrices containing lubricating agents deposited on the surface thereof, which fabric is characterised in that the coating has been applied as a foam. The invention further encompasses a method of making a lubricating fabric according to the first embodiment which method comprises reducing the absorbancy of the threads of said fabric by at least 50 % by printing or coating said threads with a surface sealant and thereafter applying a coating selected from the group consisting of silicone elastomers and resin matrices containing lubricating agents on the surface of the fabric of reduced absorbancy. Superior results are obtained where the absorbency of polyfilamentous threads has been reduced by at least 50% prior to application thereto of said silicone elastomer. This is most readily achieved by conventional techniques of coating or printing onto the fabric with appropriate coating compounds or inks. While the invention is not limited thereto, a highly desirable embodiment of the device is one wherein the fabric is part of the upper surface of an ironing board cover and the lubricating coating is at least a strip provided thereon. The lubricating coating may cover the entire upper surface of the cover. Thus such a device would comprise a cotton fabric, previously printed with an ink containing a binder component, such as an acrylic resin binder conventionally used in such inks and coated with at least 3 g/m², dry loading, of at least one lubricating agent, suitably of silicone elastomer or a resin matrix such as acrylic/carnauba wax compound. In the operation of the device, the hot laundry iron, having a sole plate temperature of between about 100°C and 290°C, is run over the coated fabric with normal pressure. The lubrication provided by a single pass reduces iron drag by 20 to 50% and is adequate for the ironing of at least one large garment without need for a second pass. The greater the sole temperature of the iron, the greater the drag reduction. The Figure shows a plan view of an ironing board cover having a lubricating area in accordance with the present invention. Figure 1 comprises a conventional ironing board cover 12 having a draw string channel 28 containing draw string 29 for affixing said cover on top of an ironing board. Strip 14 is a portion of fabric 12 of the ironing board cover having been coated with the elastomeric coating of the present invention. The lubricants used in the coatings of the present invention are non-greasy lubricants. The lubricants are incorporated in a coating containing binders which are included but not limited to vinyl, vinyl acetate, acrylic, urethane, silicone, and silicone rubber. Among the lubricants which give rise to such an effect are dihydrogenated tallowdialkyl ammonium alkyl salts, such as dihydrogen tallowdimethylammonium methyl sulfate, coconut fatty acid soaps, waxes, suitably of melting point above 60°C, such as paraffin waxes, carnauba waxes and silicone, silicone elastomers and acrylic/carnauba wax mixtures have been found the most practical. The dihydrogenated tallow alkylammonium alkyl salts, while giving excellent ironing lubrication, had very poor scorch resistance. Similarly, the coconut fatty acid soap, while it had excellent lubrication and poor scorch resistance, also generated an objectional odor under heat. The paraffin wax while again a good lubricant, generated smoke and wax odor. Moreover, the duration of lubrication is exceedingly short (less than five minutes) and the wax rapidly vaporized under the application of heat. Silicone rubbers while known for their ability to provide a smooth surface, are not generally noted for their lubricating qualities (in contrast to certain silicone oils which are known to have this property and are widely commercially used to this purpose). The basis to the present invention was noted during certain experiments relating to the puncture resistance of calendared urethane foam coated with silicone rubbers. As a result of these experiments tests were carried out to determine the parameters of this property. It was noted that optimum results were obtained when the coating was on the surface of the substrate. It is, of course, possible to place a substantially unbroken silicone surface upon any substrate over which a hot iron may pass. Such an approach however, is needlessly consumptive of expensive silicone elastomer materials. When these silicone elastomer materials were coated upon untreated fabric materials, the aqueous emulsion containing the silicone elastomers was absorbed into the interstices of the fibers in the threads to such an extent that an insufficiently large amount of silicone elastomer was available for contact with the iron sole. It was found that this disadvantage could be avoided by pretreating the fabric with conventional processes such as those normally utilized to print a color or a decorative pattern upon the fabric or pre-coating the fabric. Pigment printing or coating normally contains an acrylic binder to adhere pigment fillers, etc. to the fabric. This also acts as a surface sealant wherein the absorbency in the fabric is reduced by at least 50%. The availability of the coating containing lubricating agents to the iron soleplate was substantially amplified. It was further found that by incorporating a foaming agent in the coating compound and applying the coating as a foam, penetration was reduced sufficiently to achieve the desired result. While coating loadings as low as 3 g/m² (dry weight) of lubricant, suitably silicone elastomer, give rise to noticeable improvements in reduction of drag, it is desirable to utilize loadings of the order of from about 12 to about 60 g/m², depending on the lubricant resin combination used and the ratio of lubrication to binder. It also has been found that only a very small amount of lubricating agent is necessary to be transferred to the soleplate of the iron to significantly enhance the drag reduction. It was found that less than 0.01 grams achieves the desired results. For ease of manufacture, it is preferred to utilize water based silicone elastomers and other acrylic emulsion resins. These materials also have good heat resistance, an important characteristic, since these materials will be subjected to temperatures of up to 250°C. While the actual composition of such elastomers and emulsions are considered as trade secrets by their manufactures, they are broadly available commercially and relevant physical characteristics therefore are published. An example of suitable elastomers which may be employed for the present purpose is Union Carbide LE-9300 Silicone Emulsion, manufactured by Union Carbide Corporation, Danbury, Connecticut. SLE-5300 and SLE 5500 manufactured by General Electric Company Silicone Products Division, Waterford, New York may also be employed, however, these materials are supplied as two component silicone liquid elastomers and must be applied together with the curing agent in accordance with the manufactures instructions. Most preferred however, are silicone water based elastomers such as Dow Corning 3-5024 or 3-5025, manufactured by the Dow Corning Corporation of Midland, Michigan. These elastomers do not require the presence of a curing agent and cure in approximately two hours at ambient temperature, although the cure time can be accelerated by raising the temperature or lowering the humidity. Suitably is utilized an aqueous suspension of the silicone elastomer diluted with between 5 and 30%, suitably about 20% water containing a thickening agent suitably a premixed cellulosic thickening agent such as Methocel® F4M (manufactured by Dow Chemical Company) to the extent of from about 0.25 to 2 suitably about 1% by weight, to provide a composition suitable for printing onto the fabric substrate. In the preferred procedure the composition is printed onto the fabric substrate. The composition can be deposited on the substrate by printing through a mesh screen, or can be knife, roller, or spray coated. Examples of suitable acrylic emulsion resins which may be employed for the present purpose are Rhoplex® HA-18, Rhoplex® HA-12, Rhoplex® HA-16 manufactured by Rohm and Haas Company Philadelphia, PA.; UCAR® Latex 862, UCAR® Latex 865, UCAR® Latex 874, manufactured by Union Carbide Corporation, New York, N. Y. and WRL 0402, manufactured by Walsh Chemical Corp., Gastonia, North Carolina. These resins are normally dried and cured for approximately one minute at 163°C (325°F). Carnauba Wax in emulsion form such as Duramul® 0814, manufactured by Astor Wax in Harrison, New York is employed as a lubricating agent. The ratio of wax to resin can be ranged from 0.5:1 to 4.0:1 with the preferred level approximately 3.0:1, wax:resin. Alternatively, the emulsion may be formulated in a water based foam which is then coated or printed onto the surface of the fabric. The advantage of the foam deposition method is that it reduces the incidence of fiber penetration and enhances the deposition of the lubricating coating upon the surface of the fabric substrate. EXAMPLE I Formulation: Water 20 g Dow Corning Silicone 3-5024 100 g Methocel® F4M 1 g The material was mixed at room temperature to provide a paste suitable for printing and was applied by printing through a 0,42 mm (40 mesh) screen upon a printed cotton fabric. Said cotton fabric had previously been printed with a printing compound containing an acrylic resin binder. EXAMPLE II Formulation: Water 60.0 g Methocel® F4M 1.5 g Rhoplex® HA-12 10.0 g Duramul® 0814 30.0 g Wax-resin (solids) ratio 2.33/1.0 The material was mixed at room temperature to provide a paste suitable for printing and was applied by printing through a 0,42 mm (40 mesh) screen upon a printed cotton fabric. Said cotton fabric had previously been printed with a printing compound containing an acrylic resin binder. Coating Wt. g/m 2: 11.3, Iron Drag Reduction: 55.5% In accordance with the above procedure, but in place of Rhoplex, there are employed similar formulations of polyvinyl acetate, polyvinyl chloride, poly(styrene/ acrylic), poly(styrene/butadiene), polyurethane, epoxy resins. Similarly, in place of Duramul®, the polymers are formulated with fatty acids, silicone oils and high melting waxes. EXAMPLE III Foam Formulation: Water 60.0 (premix at 49°C (120°F)) Methocel® F4M 0.75 (premix at 49°C (120°F)) Rhoplex® HA-12 (45% solids) 10.0 Duramul® 0814 (35% solids) 30.0 100.75 Wax-resin (solids) ratio 2.33/1.0 The formulation was foamed in a Hobart Kitchen Aid mixer, Model K5SS to a density of 200 g/liter. The foam coating applied to printed bleached cotton sheeting with a spatula. The coating was dried in a 163°C (325°F) convection oven for five minutes to yield a coating weight: 5.0 g/m². The effectiveness of iron lubrication was measured by following Magla test method described in Example IV below. Drag reduction : 70% EXAMPLE IV Measurement of iron lubrication. The apparatus comprises a Dayton gear motor attached to a Wagner 102 force dial which in turn, is attachable to the iron under test. A piece of clean fabric is provided on top of a horizontal ironing board. The potential distance of travel of the iron is 86 cm. The iron is heated to a predetermined temperature suitably, about 245°C and rubbed vigorously three times over the sample silicone coating. The iron is then placed at one end of the test path, a weight of approximately 3.5 kg is placed on the iron and the force dial attached to the iron. The gear motor is then activated to run at constant speed and the reading on the force dial measured when the front of the iron passes the halfway point on the path i.e. 43 cm.

Claims: A laundry iron lubricating fabric having a coating selected from the group consisting of silicone elastomers and resin matrices containing lubricating agents deposited on the surface thereof, characterised in that the fabric has been pretreated with a surface sealant or pre-coated therewith. A laundry iron lubricating fabric having a coating selected from the group consisting of silicone elastomers and resin matrices containing lubricating agents deposited on the surface thereof, characterised in that for reducing the penetration of the coating into the fabric the coating has been applied as a foam. A fabric of claim 1 or 2, characterised in that it is coated with at least 3 g/m² dry loading of said coating. A fabric ironing board cover having at least a segment thereof made of a lubricating fabric of claim 1 or 3. A fabric ironing board cover having at least a segment thereof made of a lubricating fabric of claim 2 or 3. A fabric or cover of one of claims 1 to 5 wherein the coating is an acrylic polymer matrix containing a wax with a melting point greater than 40 °C. A cover of claim 4, wherein the fabric segment thereof is a cotton fabric having the surface sealant printed thereon with an ink containing an acrylic resin binder. A method of making a lubricating fabric of claim 1 which comprises reducing the absorbency of the threads of said fabric by at least 50 % by printing or coating said threads with a surface sealant and thereafter applying a coating selected from the group consisting of silicone elastomers and resin matrices containing lubricating agents on the surface of the fabric of reduced absorbency.

Inventors: MATTESKY HENRY, MATTESKY, HENRY
Applicants: GLATT HERBERT, GLATT, HERBERT
Application year: 1990
Main classification: D06F79
IPC codes: D06F83, D06F79, D06F75