(54) IMPROVEMENTS IN OR RELATING TO THEMANUFACTURE OF FLEXIBLE SHEET MATERIALS(71) We, BRITISH INDUSTRIAL PLASTICS LIMITED, a Company organised under the laws of Great Britain, of 20 St. Mary's Parsonage, ManchesterM3 2NL (formerly of 77 Fountain Street, Manchester M2 2EA), do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:- This invention concerns improvements in or relating to the manufacture of flexible sheet materials.
According to the present invention, a method of manufacturing a flexible sheet material comprises:(1) providing a bonded flexible sheet material comprising at least one organic fibrous material and a resin bonding agent, said bonding agent comprising a methylolmelamine resin of general formula I
wherein R1, R2, R3, R4, R5 and R6 are each a hydrogen atom or -CH2OR group, wherein R is a hydrogen atom or methyl, ethyl or propyl group, there being from 0 to 2 moles of hydrogen atoms and from 4 to 6 moles of -CH2OR groups per mole of melamine nucleus, at least 1.5 moles of the R groups being other than hydrogen atoms, or a uron resin of general formula II
wherein R' is H, -CH2OH, or -CH2OR" where R" is an alkyl group of from I to 4carbon atoms; said resin bonding agent impregnating at least one surface of the bonded flexible sheet material;(2) decorating the surface of the laminate containing said resin, after drying of the resin, by a transfer printing technique.
The bonded flexible sheet material may be a laminate which is adhered together by the resinous bonding agent e.g. a laminate of a paper sheet and a textilefibre product, such as textured wallpaper, or a laminate of a textile fibre product and a foam. In such cases the textile fibre product may be a textile yarn, strand or woven or non-woven textile fabric. Alternatively the flexible sheet material may be a non-woven web of fibrous material bound together by the resinous bonding agent e.g. needle-punched non-woven flooring: felted sheet material.
In this specification the expression "organic fibrous material" means amaterial constituted by any natural or synthetic organic fibre such as naturalcellulosic fibres, polyester fibres, or rayon fibres.
A laminate of textile and paper preferably is produced by passing the textile fibre product through a bath containing an aqueous solution of the resin,contacting the resinated fibre product with a face of the paper sheet, and dryingand curing the resin in the fibre so that the fibre product and paper sheet becomebonded together. The bath may contain in addition to the resin an acrylic or other thermoplastic polymer latex, such as styrenesbutadiene resin, butadieneacrylonitrile resin, or polyvinyl acetate.
As an alternative, or in addition, to treating the fibre product with the resin (orresin and latex), the paper sheet may be coated or impregnated with the resin (orresin and latex).
It should be noted, however, that this can have a deleterious effect on the properties, e.g. tear strength, of the paper. As an alternative to using a resin or resin/latex bath, a spraying or roller coating technique may be used.
Preferably the textile fibre product will contain from 2 to 200/0/ by weight curedresin solids, and preferably from 15 to 50% by weight of the thermoplast polymer.
The resinous bonding agent is dried, and preferably substantially fully cured,before transfer printing is effected. Curing may be effected by any of the meansusually used to cure the particular resin used, for example by passing the laminateover a heated roller or through a radiant heat zone, optionally with application ofpressure. Partial curing, to a stage where most or all of the volatiles (particularly the noxious ones) have been evolved, may be effected prior to transfer printing,final cure taking place during the printing.
We have found that the resin specified in this invention is particularly useful insensitizing organic fibres to transfer printing techniques using conventional transferprinting papers carrying sublimable dyestuffs. In any particular instance theparticular dyestuff utilized will depend upon the nature of the materials used in theflexible sheet material and will be selected to give optimum clarity of transfer andcolour fastness. In general the dyestuff should be one which is capable of forming achemical link with the sensitizing resin.
Most commercial transfer printing papers may be used: these normallycomprise a paper carrier having on one face a design formed by printing sublimabledyestuffs, the design being transferred by contacting that face with a face of thearticle to be decorated, and heating the system to a temperature of from about 180"C to about 220"C.
The methylolmelamine and uron based resins used in this invention may beused in an aqueous or an organic solvent system, preferably an aqueous system, and will normally require to be catalysed by addition of a catalyst. Suitable catalysts are (NH4)2HPO4; (NH4)H2PO4; zinc nitrate; ammonium sulphate, nitrate, chloride or thiocyanate; phosphoric, hydrochloric or nitric acid; and organic salts. When theresin is being used with a latex, catalysts of high electrolyte content are to beavoided e.g. magnesium chloride, since such catalysts are liable to destabilise the latex.
The invention will now be described in its application to the production of a textured wallpaper.
A number of hessian yarns are led from a spool system through a bath containing in parts by weight: Primal B15 acrylic latex (Rohm & Haas) (50XÓ by weight solids) 100 partsBeetle* Lit5 155 hexamethylolmelamine resin (92% by weight solids) 10 partsMonoammonium dihydrogen phosphate (catalyst) 0.2 partsWater 50 parts *Beetle is a Registered Trade Mark of British Industrial Plastics Limited. Primal is also a Registered Trade Mark.
On emergence from the bath, 100 parts of hessian are impregnated with 100 parts of the bath solution. The impregnated hessian is then led through a heated roller system where it is adhered to the top face of a paper sheet by drying the bath solution and curing the resin. After curing, the resultant laminate is contacted with a transfer print paper and printing is effected at 2100C for 25 seconds on a heated roller system. The transfer print carrier sheet is removed, and the printed, textured wallpaper is wound for subsequent trimming and cutting as is the normal practice in wallpaper manufacture.
The transfer print paper used in this case is a standard transfer printing paper using an acetate disperse dyestuff commercially available from Jas. BroadleyLimited, design number 226.
- Obviously. modifications may be made in the process and apparatus described above. For example, the lamination and curing stages may be effected by one manufacturer and the transfer printing by another, and any of the modifications indicated above may be made. The printed textured paper may be made to suit applications other than wall papering.
WHAT WE CLAIM IS:1. A method of manufacturing a flexible sheet material which comprises: (1) providing a bonded flexible sheet material comprising at least one organic fibrous material and a resinous bonding agent, said bonding agent comprising a methylolmelamine resin of general formula I
wherein R1 R2, R3, R4, R5 and R6 are each a hydrogen atom or -CH2OR group, wherein R is a hydrogen atom or methyl, ethyl or propyl group, there being from 0 to 2 moles of hydrogen atoms and from 4 to 6 moles of -CH2OR groups per mole of melamine nucleus, at least 1.5 moles of the R groups being other than hydrogen atoms, or a uron resin of general formula II
**WARNING** end of DESC field may overlap start of CLMS **.