US 2959793 A
Description (OCR text may contain errors)
Filed Feb. 7 1957 FABRIC DOWN SPRAY COATING OF POLYVINYL ACETATE its tear resistance.
United States Patent 0 FABRICS AND FABRIC ARTICLES Angus Smith Bell, Leonard Krause, and George Hammerschmidt, London, England, assignors to British Celanese Limited, a corporation of Great Britain Filed Feb. 7, 1957, Ser. No. 638,807
Claims priority, application Great Britain Feb. 22, 1956 8 Claims. (Cl. -334) This invention relate to fabrics and fabric articles, especially articles such as eider downs, comprising a fabric envelope filled with down or other loose fibrous filling material. By loose fibrous filling material is meant filling material composed of a great number of elements each of which is a fibre or (as with down or feathers) consists of a long thin stem bearing filamentary appendages, the said elements being loosein the sense that they are capable of bodily movement past one another.
Among fibrous filling materials of the kind referred to above, down, feathers and animal fibres are particularly valued for their warmth and resilience. They have, however, a disadvantage in that they tend to work through the fabric envelope. This tendency is favoured in the case of down and feathers by the fact that the filamentary appendages can easily be bent towards one end (which may be termed the forward end') of the fibrous element so as to lie parallel to the axis of that element, but resist bending backwards towards what may be termed the rear end of the fibrous element. Inthe filling there are always in contact with the fabric envelope somefibrous elements with their rear ends in a position to poke through the interstices, but any tendency to move back is resisted since this would involve bending the filamentary appendages backwards. In animal fibres such as wool and hair a role similar to that of the filamentary appendages in feathers and down is played (but less elfectively) by the scales or scale-like projections on the surface of the fibres.
To avoid this working out of the filling in eider downs and the like fabric'articles it has been usual to employ as the material for the envelope a very closely woven fabric and to provide this fabric with a continuous coating of waxy material applied by padding followed by hot-calendering. To be limited, however, to a tightly woven fabric for the envelope imposes a very undesirable restriction of choice, and inevitably adds to the ex pense of the fabric article. such as have previously been applied to the fabric from which the envelope is constructed are undesirable from many points of view. They inevitably affect to some extent the handle and appearance of the fabric and pre- Coatings of'waxy material vent the advantageous use of certain special fabrics (e.g.
on the nature of the fabric forming the envelope which contains the filling material, it has been common practice to employ a double envelope, the inner fabric providing the necessary degree of down-proofness, and the outer fabric without regard to down-proofness. The use of the double envelope has obvious disadvantages both in respect of added cost, and of reduced softness and increased weight in the fabric article.
We have now found that a fabric which is not sufficiently closely woven to be down-proof may be rendered Owingto these limitations placed a "ice substantially so, by means of a light particulate spraydeposited coating of polyvinyl acetate or other thermoplastic polymer of mono-olefinically unsaturated compound. To form the coating the polymer is preferably sprayed on to the fabric in aqueous dispersion and precipitated in situ by drying off the aqueou medium with out forming the polymer into a continuous coating of the fabric. In this way, by applying only a small proportion of polymer, e.g. 5-25%, and preferably 10-20%, of the fabric weight, considerable increase in resistance to the passage of down or other fibrous filling materials, may be obtained without substantially affecting the appearance or handle of the fabric or undesirably decreasing its moisture permeability or its tear strength. The dispersions used are of the kind commonly termed stable dispersions or stable emulsions. (Dispersion is the more accurate term but both terms are used in the industry.) Stable here means that the dispersions can be kept for periods of at least one month without precipitation. (Actually the stable polyvinyl acetate dispersions of commerce usually remain stable for six months or more.) The stable dispersions commercially available are commonly of concentration between 50 and 60% and when using them dilution with water is therefore necessary to provide a dispersion suitable for spraying. Dilution to a solids content of 15 to 30% is generally advantageous. v
In describing the composition of the dispersion all percentages are based on the total weight of the dispersion unless otherwise stated.
Stable emulsions of the kind referred to above containing 45 to,.,60% solids, mostly polymer, e.g. 40 to 55% polymer, have now been on the market for many years and there is a large body of published information as to their preparation and properties. In this connection we would refer for instance to: Chemie and Technologie der Kunststoffe, by R. Houwink, 1942, vol. 2, pp. 161-2, Revue Generale de Caoutchouc, vol. 20 (1943), pp. 29-35, German Plastics Practice, by l. M. De Bell, W. C. Goggin and W. E. Gloor, 1946, pp. 103-111; F.I.A.T. 1102, pp. 46, Vinyl and Related Polymers, by C. E. Schildknecht, 1952, pp. 333-335, and British Patents Nos. 437,446, 466,173, 475,162, 511,036, 568,884, 577,861, 615,725, 641,653, 648,001 and 655,734. Suitable stable dispersions are sold, for instance, by Vinyl Products, Ltd. under the registered trademark Vinamul andby Dunlop Special Products Ltd., under the registered trademark Polimul.
In the stable dispersions, to assist in obtaining the desired stability against precipitation, there is usually present a suitable proportion, e.g. 1 to 3%, of a protective colloid, e.g. polyvinyl alcohol (preferably retaining a minor proportion of acetate groups, or slightly acetalized), c0- polymers of an alkali metal methacrylate with a minor proportion of methylmethacrylate, or water-soluble copolymers of vinyl acetate. Many other protective colloids are available, e.g. copolymers of styrene with soluble salts of maleic acid, methyl cellulose, hydroxyethyl cellulose, alkali-metal carboxy methyl celluloses, water-soluble colloidal carbohydrates, and polyvinyl pyrrolidone and water-soluble pyrrolidone copolymers. To ensure the desired stability the protective colloid must be selected with due regard to the other constituents of the dispersion.
In addition to the protective colloid a small proportion, e.g. 0.2 to 1%, of a wetting agent is commonly present in the dispersion with a view to controlling the particle' size and assisting in stabilising the dispersion against coagulation. The wetting agents employed are usually of the anionic kind, e.g. dioctyl sodium sulphosuccinate, sodium dodecyl benzene sulphonate or sodium alkyl naphthalene sulphonate or of the non-ionic kind, eg, alkyl phenyl polyethylene glycol ethers, polypropylene glycols, ethylene oxide adducts of cetyl and/r oleyl alcohols, polyethylene glycol oleates, and propylene oxide ethylene oxide copolymers. For the purpose of the present invention it is preferred that any wetting agent present should be of the non-ionic kind.
Polymers that can readily be obtained in the form of concentrated stable aqueous dispersions without the use of protective colloids or wetting agents can be made by copolymerising vinyl acetate or like ethylenically unsaturated ester with a small proportion of a vinyl compound containing a solubilising saline group, e.g. an alkali-metal sulphonate group. The preparation of copolymers of this kind by copolymerising vinyl acetate with a small proportion of an alkali-metal salt of vinyl sulphonate is described in U. S. Patent No. 2,300,920.
To obtain good results without using excessive amounts of polymer such as would undesirably stiffen the fabric the polymer should be plasticised internally or externally. Internal plasticisation is present in copolymers of vinyl acetate with a small proportion of a suitable comonomer, e.g. an alkyl ester of maleic, fumaric or itaconic acid, or an isopropenyl ester. External plasticisation may be achieved by incorporation in the dispersion, or in the reaction mixture from which it is formed by polymerisation, of a suitable plasticiser for the polymer. For polyvinyl acetate and copolymers of vinyl acetate with small proportions of a comonomer, dibutyl phthalate has been found generally satisfactory, alone or in admixture with other compatible plasticisers, especially di-(methylcyclo' hexyl)phthalate and triethylene glycol di-2-ethyl butyrate. For polyvinyl acetate a proportion of plasticiser amounting to to 30%, especially to 25%, of the weight of the polymer will generally be found suitable.
The process of the invention is applicable to the treatment of fabrics showing a great variety of fabric construction. It is particularly useful when applied to lightweight fabrics of cellulose acetate or natural silk and to satins.
The spraying is preferably effected by passing the fabric continuously across a spray produced by a series of spray nozzles fed with the aqueous dispersion in such a way as to provide a coating of density which is substantially uniform across the width of the fabric. The nozzles may be stationary or may be traversed in an appropriate manner. Preferably the spraying is effected only on that side of the fabric which is to be on the inside of the envelope and does not penetrate to the other surface so as not to risk marring what will be the outer surface of the article or unduly stiffening the fabric.
The temperature at which the fabric is dried after spraying must be below the temperature at which any fibre in the fabric becomes soft or sticky but may with advantage be such that individual particles of polymer deposited spread over the interstices of the fabric and adhere to the material thereof, but without forming a coherent coating over the fabric. Drying temperatures of 50 to 100 C. and especially 60 to 90 C. are generally suitable.
It is preferred to employ as the polymer polyvinyl acetate but various other polymers (some of which would have an undesirable effect on the handle or appearance of the material if used in large amounts and which would be ineffective in small amounts applied by other methods) can be employed with advantage by the method of the invention. The polymer used should be Water-insoluble, relatively soft, i.e. so as to become sticky at temperatures below 100 C., and non-crystalline without being sticky or liquid at temperatures up to about 30 C. and non-rubbery. Examples of such polymers are: polyvinyl acetate, the copolymers of vinyl acetate and of isopropenyl acetate with maleic esters, with other vinyl esters, e.g. vinyl benzoate, and with vinyl chloride, polymerised acrylic and methacrylic esters of higher alcohols, e.g. polybutylacrylate, polybutyl methacrylate, polylsobutvl acrylate, polyisobutyl methacrylate, and copolymers of acrylic and methacrylic esters with vinyl esters. In addition to spraying thefabric that is to form the envelope of the article, the mass of loose fibrous material may also be lightly sprayed with the polymer dispersion and dried before insertion in the envelope. The following examples illustrate the invention:
Example 1 The fabric employed was an eight shaft satin formed with 252 ends per inch of denier continuous-filament cellulose acetate yarn and 84 picks per inch of 140 denier yarn of the same nature.
The dispersion sprayed on to the fabric consisted of an aqueous dispersion of polyvinyl acetate containing 30% by weight of the polymer.
The spraying was effected by drawing the fabric continuously from a supply roll on to a travelling belt having a short horizontal run beneath a series of spray noz zles arranged so as to direct downwards on to the ex posed surface of the fabric a spray covering its width substantially uniformly but without forming a continuous coating.
The spray was controlled so as to deposit on the fabric 15% of its weight of the polymer. Beyond the spray the fabric was continuously drawn from the belt and through a drying chamber maintained at 60 C., and was thereafter wound up in the dry condition.
From this treated fabric an eider down was made by forming the fabric into a suitable envelope with the treated side innermost and filling this envelope with down, no inner envelope being used.
Example 2 The process was carried out as in Example 1 except that the dispersion sprayed on the fabric was made by diluting with its own volume of water a stable aqueous emulsion containing:
44% of polyvinyl acetate 11% of dibutyl phthalate, and
1.5% of a hydrolysed polyvinyl acetate containing 20 to 24% of residual acetate groups and that the spraying was effected so that after drying off the water there remained on the fabric a coatingof weight l0l5% that of the uncoated fabric.
Example 3 The process was carried out as in Example 1 except that the dispersion sprayed on to the fabric was made by diluting with its own volume of water a stable aqueous dispersion containing:
45% of polyvinyl acetate 6% of dibutyl phthalate 6% of tri-ethylene glycol di-(Z-ethyl) butyrate 1.5% of the hydrolysed polyvinyl acetate specified in Example 2, and
0.5% of polyethylene glycol 1500 mono-oleate the spraying was effected so as to leave on the fabric, after drying, a coating of weight 15-20% that of the uncoated fabric; and the drying was effected at 70 C.
Examples 4 and 5 The process was carried out as in Examples 1 to 5 respectively except that the fabric treated was a 5-shaft satin formed with 140 ends per inch of denier continuous-filament cellulose acetate yarn and 72 picks per inch of the same yarn.
Examples 11 and 12 The process was carried out as in Examples 11 and 12 respectively except that the horsehair filling before insertion in the envelope was sprayed on both sides with the same dispersion as was used on the fabric so as to leave on the sprayed material after drying a deposit amounting to 1% of the weight of the hair, and was then dried at 50 C.
Examples 15 and 16 The process was carried out as in Examples 1 and 7 respectively except that the loose fibrous material was a flock of wool fibres and the treated fabric and fibrous material were made into cushions.
In a similar way to that described above fabrics intended to form the envelope for mattresses and the like can be treated by spraying with the polymer emulsion and drying. Although this treatment is preferably effected before making the fabric envelope, which is made from fabric with the coated side innermost, the invention includes applying a similar process to the outside of the fabric envelope of an eider down or the like, the amount of polymer deposited on the material being insufiicient to affect adversely the handle or appearance of the fabric.
Preferably the fabric treated is composed of cellulose acetate fibre. This may be of normal acetyl value, i.e. 52-54% combined acetic acid, or of high acetyl value, e.g. 58-62.5% acetic acid, or of intermediate acetyl value, e.g. 54-58% acetic acid. The cellulose acetate may be present in the form of continuous filament yarns or staple fibre yarns. The process of the invention is applicable to the treatment of fabrics formed from fibres other than cellulose acetate, e.g. regenerated cellulose fibres, fibres of vinyl-type polymers such as polyvinyl chloride-acetate, vinylidene chloride, vinyl chloride copolymers, vinyl chloride acrylonitrile copolymers, vinylidene chloride acrylonitrile copolymers and other polymers of acrylonitrile including homopolymers and polymers containing small proportions of vinyl pyridine, acrylamide and other components adapted to improve the dye-aflinity of polyacrylonitrile. The fabric may also be composed of or contain a fibre-forming polyamide, e.g. nylon 6, nylon 66 or nylon 610 or a fibre-forming polyester such as polyethylene terephthalate. Fabrics composed or containing natural fibres, e.g. cotton, linen, silk or wool may also be treated according to the invention. The fabrics may contain two o more of these fibre-forming materials in admixture.
The invention is of particular importance in the manufacture of fabric articles in which the filling material is composed of or contains down, feathers or animal fibres. The method of the invention may, however, also be employed in making fabric articles containing other kinds of loose fibrous filling material e.g. material of kapok or of any of the fibres referred to above, in the form of flock or batting.
The accompanying drawing shows in sectional elevation a quilt constructed according to the invention.
Having described our invention, what we desire to secure by Letters Patent is:
1. An article comprising a fabric envelope filled with loose fibrous material selected from the group consisting of down, horsehair and feathers, the interstices of said fabric being substantially sealed against escape of the fibrous material by means of a particulate spray-deposited coating of polyvinyl acetate containing a plasticizer therefor.
2. An article comprising a fabric envelope filled with I loose fibrous material, wherein said material is down, the fabric is Woven from continuous filament yarns and is substantially sealed against escape of down by means of a particulate spray-deposited coating on its inner surface, the weight of said coating being 10-20% of the weight of the fabric and the coating being composed of a mixture of polyvinyl acetate with 1030% of its weight of a plasticiser therefor.
3. An article comprising a fabric envelope filled with loose fibrous material, wherein said material is feathers, the fabric is woven from continuous filament yarns and is substantially sealed against escape of feathers by means of a particulate spray-deposited coating on its inner surface, the weight of said coating being 1020% of the weight of the fabric and the coating being composed of a mixture of polyvinyl acetate with 1030% of its weight of a plasticiser therefor.
4. An article comprising a fabric envelope filled with loose fibrous material, wherein said material is horsehair, the fabric is woven from continuous filament yarns and is substantially sealed against escape of horsehair by means of a particulate spray-deposited coating on its inner surface, the weight of said coating being 1020% of the weight of the fabric and the coating being composed of a mixture of polyvinyl'acetate with 1030% of its weight of a plasticiser therefor.
5. An article according to claim 2, wherein the yarn is of cellulose triacetate.
6. An article according to claim 3, wherein the yarn is of cellulose acetate.
7. An article according to claim 4, wherein the yarn is of cellulose acetate.
8. An article comprising a fabric envelope filled with loose fibrous material selected from the group consisting of down, horsehair and feathers, the interstices of said fabric being substantially sealed against escape of the fibrous material by means of a particulate spray-deposited coating of polyvinyl acetate containing about 10 to 30% of its weight of a plasticizer therefor, said coating being provided on both surfaces of said fabric and being present in about 5 to 25% of the weight of said fabric.
References Cited in the file of this patent UNITED STATES PATENTS 2,016,601 Hlavaty Oct. 8, 1935 2,371,618 Hanson et a1 Mar. 20, 1945 2,423,185 Guudel et al. July 1, 1947 2,431,745 Flanagan Dec. 2, 1947 2,544,797 Lippmann Mar. 13, 1951 2,579,035 Edelrnan Dec. 18, 1951 2,580,202 Talalay et al Dec. 25, 1951 2,616,486 Hawley et a1 Nov. 4, 1952 2,778,411 Clark Jan. 22, 1957 2,798,820 Nelson July 9, 1957