A PROCESS FOR THE PRODUCTION OF PADDING LAYERS, AND PADDING MADE BY SUCH PROCESS

Abstract: A process for the production of padding layers having a high degree of thermal insulation, and particularly suitable for use in clothing and furnishing, comprises the steps of producing, by means of carding machines, a layer or web (1) comprising a mixture of polyester fibres with silicone treated fibres of the same or different nature. This layer or web (1) is then resin coated on one side with a mixture of sticky plastic adhesives which, when poiymerised, form a very soft and elastic film; on the other side of the same layer a non-sticky adhesive is sprayed or otherwise applied and the thus treated web is then subjected to a calendering operation at a temperature varying between predetermined limits. Subse­ quently, a layer (2) of metal particles embedded in synthetic resins is applied to one or both sides of the said web (1) in such a way as to form a thermal barrier operable to reduce the transmission of heat by radiation and convection through the padding thus formed.

Description: The present invention relates to a process for the production of padding having a high degree of thermal insulation, and particularly to padding which is usable for clothing and furnishings, although it is to be understood that the padding of the invention is not limited to such use. In an earlier patent application by the same applicant (Italian Patent application No: 20978 A/84 filed 17 May, 1984), the disclosure of which is incorporated herein by reference, there is illustrated a process for the production of a padding suitable for use in clothing, furnishing or the like, which consists, substantially, in producing a layer of fibres, preferably of polyester or the like, mixed with silicone treated fibres of various natures, which upon carding is formed into a soft, light web which is subsequently surface treated on one face with a mixture of sticky plastics adhesives so as to form, after polymerisation, a very soft and elastic film; on the other side of the layer, on the other hand, there is applied an adhesive of different nature, which is not sticky. The thus treated layer is then subjected to a calendering operation at variable temperature and pressures, in such a way as conveniently to reduce the initial thickness, and during this calendering operation, for a certain very short period of time, one of the cylinders of the calender remains in adhesive contact with the sticky surface on the said one face of the web, consequently creating an expansion which substantially forms air pockets within the interior of the padding. Padding formed in accordance with this earlier invention has thermal insulation characteristics which are a significant improvement over those encountered in conventional paddings of previously known type which, among other things, are generally rather thick and therefore do not lend themselves well to use in clothing; moreover, such known padding materials do not have such good thermal insulation characteristics as can be achieved with the padding material of the applicant's earlier invention forming the subject of the patent application referred to above. The present invention seeks to provide a padding material, and a process for the production of same, which will have further and significantly improved thermal insulation characteristics, and will be more compact and manageable than hithertofore known padding materials. The present invention also seeks to provide a padding material which can be used more conveniently for clothing or furnishings than prior art padding materials which will have exceptional thermal insulation characteristics without however relinquishing the characteristics of softness, elasticity and pleasantness to the touch typical of padding materials generally. Finally, the present invention seeks to provide a process which leads to the production of a padding which, as well as having significantly improved characteristics, is more aesthetically pleasing than previously known paddings and which, moreover, is more easily workable than prior art padding materials. According to one aspect of the present invention, there is provided a process for the production of padding having a high degree of thermal insulation, usable for clothing and furnishing, comprising the steps of: first producing a web comprising a layer obtained by carding a mixture of fibres of polyester or other fibres with silicone treated fibres of diverse nature and origin, resin coating the said web, on one face thereof, with a mixture of adhesives having a sticky plastic consistency, which, when polymerised, form a soft, elastic film, spraying onto the opposite face from said one face of said web a non sticky adhesive; calendering the layer thus treated at a variable temperature, and subsequently applying to at least one face of said web a surface layer of metal particles embedded in a synthetic resin. According to another aspect of the present invention there is provided padding made by a process as defined hereinabove comprising a sheet-like body constituted by a web of carded fibres surface treated with a mixture of plastics adhesives and calendered to create a reduction in thickness and an associated surface compaction, and at least one surface layer on said sheet-like body composed of metal particles embedded in a synthetic resin. Various embodiments of the invention will now be more particularly described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a perspective view of a starting layer comprising a web of mixed fibres including polyester fibres and silicone treated fibres of the same or a different nature; Figure 2 is a perspective view of the same web after the application, to one of its faces, of a layer of metal particles embedded in synthetic resin; Figure 3 is a perspective view of the same web after the application, to the other of its faces, of a further layer of metal particles embedded in a synthetic resin; Figures 4 and 5 are cross sections taken on the lines IV-IV and V-V of Figures 2 and 3 respectively; Figure 6 is a cross section showing two superimposed layers treated on one side only; and Figure 7 is a cross section showing two superimposed layers treated on both sides. With reference to the various figures of the accompanying drawings, the process of the invention for the production of padding with a high degree of thermal insulation comprises the preliminary production of a layer or web 1 in accordacne with the teaching of the applicant's earlier patent application referred to hereinabove (namely Italian patent application No: 20978 A/84), and then onto this web 1 there is applied a layer 2 of metal particles embedded in synthetic resin as shown in Figure 2. Simultaneously or subsequently a second layer of metal particles embedded in a synthetic resin may be applied to the opposite face of the web 1 as shown in Figure 3. More precisely, the or each said layer is constituted by an acrylic or polyurethane or vinyl resin, which may be in emulsion or in a solvent, pigmented with aluminium or any other metal powder, in such a way as to confer a metallised appearance to the surface of the product. If emulsions are used, these latter will be in aqueous phase, whilst if the said resins are in solution, the solvents used may be esters, ketones, dimethylformamides, aromatic hydrocarbons and the like. The said layer of resin and metallic powders may be applied on the web of padding by metallisation in a high vacuum, by either direct or "transfer" stamping, or by means of spreading or spraying, which may also be in direct form or by "transfer" techniques. Direct metallisation of a surface of the padding, however, presents not insiginificant practical and economic problems. Such a process, in fact, is substantially discontinuous and, moreover, the material (wadding) to be subjected to this process is very voluminous so that the length of the rolls of material which can be introduced into a conventional metallisation installation is necessarily limited and the full metallisation capacity of such an installation cannot be adequately utilised. An excessively low productivity is therefore experienced. More advantageously a "transfer" process involving the preliminary metallisation of a film of plastics material is envisaged. Preferably, a polyester film with a thickness in the region of 12-25 µm is used in such a process. For this process the film is preliminarily treated with a release medium such as an anti-adhesive lacquer, and then the metal is applied to it by any known metallisation technique. The metal is then transferred to the web of wadding by means of a hot calendering operation using a calender operating, for example, at a speed of around 30 m/min and at a temperature of 100-140⁰C and with a specific pressure of 10-30 mg/cm². With a process such as that indicated above it is possible easily to obtain metallisation of different colours including silver, gold and bronze, with very important aesthetic effects from a commercial point of view. The application of a metallised layer by spreading or spraying onto a substrate is also a known technique. This comprises spreading or spraying an emulsion, or better (since this allows aesthetically more pleasing results to be obtained) a solution of resins in organic solvents in which metal pigments (generally aluminium) and organic colorants have been dispersed to impart a different coloration to the solution itself. The most suitable resins for this purpose for the particular application of metallising onto synthetic fibre wadding are, as already indicated, acrylic, vinyl and polyurethane resins. The following examples illustrate, purely by way of example, various typical solutions which may be formed by means of the said resins. Acrylic resin : Paraloid B72 ppm 60 (Rohm & Haas) cellulose acetobutyrate ppm 90 (Bayer) metal pigment ppm 50 organic pigment ppm 0-5 toluene ppm 200 ethyl acetate ppm 100 isobutyl acetate ppm 100 total solid 33% viscosity 5-10,000 cP. In use it will of course be necessary to bring the solid content and the viscosity to values suited to the particular system of application. Vinyl resin : Paraloid A30 ppm 10 (Rulum & Hans) vinylite VyHH ppm 85 (Union Carbide) cellulose acetobutyrate ppm 5 (Bayer) metal pigment ppm 20 toluene ppm 50 methyl ethyl ketone ppm 150 ethyl acetate ppm 20 isobutyl acetate ppm 20 total solid 33% viscosity 5-10,000 cP. Polyurethane resin : polyurethane resin ppm 35 (Larithane Ms 132) aromatic polyester (Larim S.p.A.) dimethylformamide ppm 65 metal pigment ppm 50 total solid 43% viscosity 8-120,000 cP. Whilst acrylic resins are more suitable for application by spray techniques, vinyl and polyurethane resins lend themselves greatly to application by spreading. Spray application can be effected using known techniques. After drying the material is calendered (to improve the appearnace of the wadding) at a temperature for example of 100-120 o C at a speed of about 30 m/min. Application by spreading is considered more practical and more economically convenient, and in general spreading by so-called "transfer" or "offset" techniques is preferred in that it permits more brilliant and technically more controllable and interesting results to be obtained. The technology for transfer or offset spreading is substantially known: this involves the application, to a suitably devised release medium (such as anti-adhesive paper) which may have a polished, semi-polished, matt or embossed or other finish, a resin solution of a thickness considered most suitable (generally in thicknesses of 100-200 µm) using a roller-doctor blade system. The spread layer of solution is brought into contact with a web of wadding and the whole assembly then passed into a drying furnace at 100-180 o C in which the solvent is completely evaporated. At the output of the furnace the assembly is cooled, the padding on which the resin has been deposited, by now completely dried, is separated from the release medium and wound in rolls. The release medium (anti-adhesive paper) is also wound up separately and re-utilised. The whole operation is conducted at a speed of between 10 and 50 m/min according to the type of resin and wadding and acccording to the desired characteristics of the finished product. It is suitable at this point to make it clear that, whichever method of its application to the web of wadding the thickness of the layer can vary within wide limits in dependence on the final utilisation envisaged for the padding itself. Further, the metallisation operation can obviously be effected on any other type of padding for clothing and furnishing. The layer which is obtained on the surface of the web of wadding is, preferably, several microns thick and such as to form a surface film having significant elasticity in such a way as not to prejudice in any way the typical characteristics of softness and suppleness of the padding. The application of the said surface layer is physically of significant importance in that it substantially forms a barrier layer which is largely impermeable to air from the outside (up to 80%) but such as not to retain moisture vapour or cause condensation within the layer. The physical characteristics of the metallised layer are such that, when it is applied to the face which will be the outside of the padding (that is on the opposite face from that nearest to the body in a case in which the padding is to be utilised for clothing) it significantly reduces the transmission of heat by convection. The presence of an almost air impermeable layer, in fact, causes the creation within the layer of padding of a cushion or air pocket which remains almost static and which, consequently, constitutes a notable thermal barrier not allowing the dispersion of heat towards the outside: The padding thus formed also has notable improvements as far as the transmission of heat by radiation is concerned in that the layer of metal particles, preferably of aluminium, but which may be of other substances forms in a sense, a heat reflective surface such that the heat within the padding layer is not transmitted by radiation to the outside, but reflected back towards the inside thus further increasing the insulating factor of the layer: As far as the transmission of heat by conduction is concerned, the very small thickness of the metal particle-containing layer is such as not to cause appreciable variations in the heat transmitted by conduction. The metallised layer which is formed on the surface of the wadding is suitably permeable to moisture so that possible condensation phenomena are avoided, which phenomena could result in the formation of condensation within the interior of the layer, which would be detrimental to the insulating properties of the padding in that the condensate would in practice fill cavities or zones which, otherwise,would be filled with air. The metallised layer, as well as being elastic and soft, thus permits any possible condensation or moisture which may form within the padding to escape therefrom thus contributing to an improvement in the health characteristics of the product. Another important aspect of the invention is constituted by the fact that the metallised surface layer, being composed of metal particles embedded in a synthetic resin, has the function of conferring a greater compactness and dimensional stability to the padding layer thus formed, making this latter thus more easily workable (for example in the production of windcheater jackets and quilting) in that any fraying which might otherwise occur in correspondence with the cut edges is significantly reduced. Because of this the said metallised surface layer is able to facilitate the washing operations on the finished product as well as exerting a definite locking action on the surface fibres allowing the padding to be used with any type of fabric, even very light fabric, without the possibility of hairs, down or fibres escaping therefrom. Moreover, the product obtained is very consistent, thus making it unnecessary to perform stitching through of the manufactured product, as was previously necessary in order to maintain the fabric and padding connected together. Further, the layers of padding thus formed can be joined together in such a way as to provide a composite padding (as shown in Figures 6 and 7) comprising two or more layers, incorporating one or more thermal barriers within the thickness of the composite layer as well as one or more surface layer. The presence of the metallised surface layer contributes, moreover, to improving the appearance and presentation of the product in that it presents a brilliant surface aspect due to the presence of the metal particles in the resin; the metal particles do not, however, prejudice the characteristics of softness to the touch and elasticity of the padding.

Claims: A process for the production of padding having a high degree of thermal insulation, usable for clothing and furnishing, comprising the steps of: first producing a web (1) comprising a layer obtained by carding a mixture of fibres of polyester or other fibres with silicone treated fibres of diverse nature and origin, resin coating the said web (1), on one face thereof, with a mixture of adhesives having a sticky plastic consistency which, when polymerised, form a soft, elastic film, spraying onto the opposite face from said one face of said web (1) a non sticky adhesive; calendering the layer thus treated at a variable temperature, and subsequently applying to at least one face of said web (1) a surface layer (2) of metal particles embedded in a synthetic resin. A process according to Claim 1, characterised in that the said synthetic resin of said surface layer (2) is either an acrylic resin, a polyurethane or a vinyl resin in the form of either an emulsion in acqueous phase or a solution in a solvent comprising either an ester, a ketone, a dimethylformamide or an aromatic hydrocarbon, and is pigmented with a metal powder whereby to confer a metallised appearance to the said surface of said web (1). A process according to Claim 1 or Claim 2 characterised in that the said layer (2) of resin and metal powder is applied to the said web (1) by metallisation under high vacuum, by direct or transfer spreading or by spraying. A process according to Claim 3, characterised in that it includes the steps of: preliminarily treating a film of plastics material with an anti-adhesive lacquer, metallisation of said film of plastics material with a metal layer having a thickness in the range 12-25 µm, and transferring the said metallised layer onto the said web (1) of padding by means of a hot calendering operation using a calender operating at a speed in the region of 30 m/min at a pressure in the region of 10-30 kg per cm². A process according to Claim 1, characterised in that either an emulsion or a solution of resins in organic solvents in which are dispersed metal pigments and organic colorants is applied directly onto the said web (1) of padding by spreading or by spraying. A process according to Claim 5, characterised in that the said solution of resins is composed of the following constituents: Paraloid B72 ppm 60 (Rohm & Haas) cellulose acetobutyrate ppm 90 (Bayer) metal pigment ppm 50 organic pigment ppm 0-5 toluene ppm 200 ethyl acetate ppm 100 isobutyle acetate ppm 1000 with a total solid content of 33% and a viscosity in the range 5-10,000 cP. A process according to Claim 5, characterised in that the said solution of resins is composed of the following constituents: Paraloid A30 ppm 10 (Rohm & Haas) vinylite VyHH ppm 85 ( Union Carbide) cellulose acetobutyrate ppm 5 (Bayer) metal pigment ppm 20 toluene ppm 50 methyl ethyl ketone ppm 150 ethyl acetate ppm 20 isobutyl acetate ppm 20 with a total solid content of 33% and a viscosity in the range 5-10,000 cP. A process according to Claim 5, characterised in that the said solution of resins is composed of the following constituents: polyurethane resin ppm 35 (Larithane Ms 132) (polyester, aromatic) (Larim S.p.A.) dimethylformamide ppm 65 metal pigment ppm 50 with a total solid content of 43% and a viscosity in the range 8-120,000 cP. A process according to any preceding Claim, characterised in that the said metallised layer (2) is dried after application thereof and the padding material is then calendered at temperatures in the region of 100-120 o C at a speed of about 30 m/min. A process according to any preceding Claim, characterised in that the said metallised layer (2) is formed on said web (1) by using a transfer process comprising the steps of: providing a release sheet having a polished, semi-polished, opaque, embossed or other finish, applying the said resin solution, incorporating the said metal particles and a solvent for the said resin to the said release sheet in a thickness considered most suitable, using a roller and doctor blade system; contacting the said layer of thus spread resin solution with the web (1) of padding material; passing the said composite assembly into a drying furnace at a temperature in the range 100-180 o C whereby said solvent is completely evaporated; removing the said composite assembly from the said furnace, cooling the said composite assembly, separating the said web (1) of padding on which resin has beer deposited and by now completely dried, from the said release sheet, and winding the said cooled padding in rolls. A process according to Claim 10, characterised in that the said operations are conducted at a speed in the rage of 10-50 m/min. A process for the production of padding having a high degree of thermal insulation, including the step of applying to at least one face of a web (1) of padding material a surface layer (2) having metal particles embedded in a synthetic resin. Padding made by means of the process of Claim 1, comprising a sheet-like body constituted by a web (1) of carded fibres surface treated with a mixture of plastics adhesives and calendered, characterized in that said padding further comprise at least one surface layer on said sheet-like body composed of metal particles embedded in a synthetic resin, and said surface layer (2) is substantially impermeable to air and substantially permeable to water vapour whereby to facilitate washing of the finished product, said surface layer further serving to fix the fibres of said sheet-like body layer allowing the use of said padding with any type of fabric without the possibility of the hairs or fibres escaping therefrom. A composite padding, characterised by comprising two or more layers of a padding material according to Claim 13 joined together in face-to-face relationship by at least one of said surface layers (2) composed of metal particles embedded in synthetic resin.

Inventors: SINISCALCHI, LUCIANO
Applicants: FISI FIBRE SINTETICHE S.P.A.
Application year: 1985
Main classification: D04H1
IPC codes: D06M13, D06M15, D06M17, B32B5, D06M101, D06N7, D04H1