US3467571A - Hat felt and the method of making it - Google Patents

Description

United States Patent 3,467,571 HAT FELT AND THE METHOD OF MAKING IT Jacques Schweig, Montreux, and Horst Charwat, Monthey, Switzerland, assignors, by mesne assignments, to Jacques Schweig, Montreux, Switzerland No Drawing. Continuation of application Ser. No. 283,582, May 27, 1963. This application Jan. 6, 1967, Ser. No. 607,851 Claims priority, application Switzerland, Nov. 12, 1962, 13,218/ 62 Int. Cl. D04h 1/12; B32b 9/04 US. Cl. 161-170 2 Claims ABSTRACT OF THE DISCLOSURE A method for producing hat felt from a mixture of fibers containing an unrestricted proportion of synthetic fibers which comprises intimately admixing natural and/ or synthetic fibers by air blowing the same, suctiondcpositing the resultant mixture on a conical support form in a doubling machine, spraying the resultant loose fiber fleece with hot water, removing the so-obtained prestiffened hat felt from said form, subjecting said hat felt to centrifugal drying, applying to the resultant compacted and substantially water-free hat felt an aqueous solution, dispersion or emulsion of heat-curable synthetic plastic, and then subjecting the resultant felt to heat-curing to give the hat felt its final form; and the resultant products.

This application is a continuation of copending application, Ser. No. 283,582, filed May 27, 1963 (allowed and forfeited).

The present invention relates to a process for the manufacture of hat felt.

Unformed felt hats or hat felts known to date are produced from animal fibers, e.g. hare or rabbit hairs, wool, etc., possibly mixed with synthetic fibers. In the selection of such fibers, it was previously endeavoured to use those having a natural felting property or a felting property increased by special treatments.

The felting properties of the raw materials is-as is generally knownone of the most important provisions for attaining a good quality of hat felt.

Since synthetic fibers have no or in general an insufiicient felting property, one could previously only use a restricted percentual amount of synthetic fibers in the manufacture of hat felt.

It has now surprisingly been found that the selection of the raw materials to be used as starting materials is not necessarily bound to the requirement of felting ability so that, by reason of the present invention, synthetic fibers can now also be employed in any desired quantity. Any desired fibers of natural or synthetic origin or, if desired, mixtures of such natural and synthetic fibers can now be mixed in conventional manner in a blower machine to form a fiber fleece which is then caused by means of suction to deposit in a doubling machine on a conical support form, a removable fleece thereby forming, preferably by treatment with hot water, as crude form for hat felts or bands for hats.

The process of the invention is characterized in that the hat felts formed on the conical support form are treated with at least one synthetic plastic in the form of a solution, dispersion or emulsion, whereafter the synthetic plastic is cured by heat treatment in order to give the hat felt its final form.

According to the synthetic plastic or plastics chosen, the same will be employed in the form of a solution, dispersion or emulsion.

r" a C6 Appropriate synthetic plastics for the purposes of the invention include solutions and/or dispersions of thermoplasts such as, for example, vinyl polymers, e.g. PVC or polyvinyl acetate, polyalkenes, e.g. polyethylene, polypropylene, etc., dienes, e.g. polybutadiene, acrylic esters and derivatives thereof, e.g. acrylic acid butyl ester, methacrylic acid butyl ester, etc., amides of polyacrylic acid or of polymethacrylic acid, acrylonitrile etc., also aminoplasts such as, for example, formaldehyde precondensates of melamine, of urea, of acetylene diurea, etc. A suitable catalyst for the purposes of the invention is, for example, ammonium chloride.

The following are particularly suitable for the purposes of the invention:

(a) The combination of a dispersion or solution of a high polymer material with reactive groups, e.g. amido groups with a melamine formaldehyde precondensate. By means of condensation of the impregnated and dried felt in the presence of a potential acid, e.g. ammonium chloride, at temperatures exceeding 0., preferably -l50 C., a cross-linking of the binder with melamine resin is attained and the stability of swell of the synthetic plastic significantly improved.

(b) The use of a binder with polymerized reactive groups which cause self-cross-linking after drying at an elevated temperature.

The curing process is effected in accordance with the composition of the synthetic plastic material, preferably at 100 C. to C.

As already mentioned, the selection of the fiber material is no longer subject to any conditions. The previously employed expensive animal fibers may be partial- 1y or entirely replaced with advantage by suitable synthetic fibers. In particular, polyacrylonitrile fibers, e.g. the trademark products Dralon and Orlon have proven suitable for the purpose of the invention. Other fully synthetic fibers, such as polyamides or polyurethanes, e.g. the trademark products Nylon and Perlon, polyvinyl fibers, e.g. PC fibers, etc., as well as polyterephthalic acid esters, such as, for example, the trademark products Dacron and Terylene, and many others have, however, also proven suitable. If desired, mixtures of such fully synthetic fibers may also be used.

The following advantages can be obtained by means of the process of the invention:

(1) Independence from expensive raw material which previously also had to possess the properties of felting;

(2) Omission of complicated and expensive felting machines;

(3) Saving of labor (no necessity for trained workers);

(4) No wastage losses occurring by reason of the particular preparation method;

(5) Reduction in manufacturing costs of the hat felts;

(6) An improvement in quality when using synthetic fibers (stability of shape, elasticity, light weight).

The process of the invention can, for example, be performed as follows:

Rabbit hairs and polyacrylonitrile fibers, e.g. fibers of Dralon or Orion are mixed in a so-called blower machine known in the hat industry, in accordance with the air current principle. Weighed amounts of this fibrous mixture are then caused by means of suction to deposit on perforated so-called doubling machines. After this depositing process, the thus formed fiber fleece layer is sprayed with hot water. The pre-stiffening caused thereby can, if desired, be increased by subjecting the hat felt removed from the support form to a felting process in a suitable, conventional felting machine, whereby a good intertwining of the rabbit hairs with the polyacrylonitrile fibers is obtained.

As great as possible an amount of water, absorbed by the hat felt in the pre-stiifening step, is removed from the hat felt formed in the above said manner in a centrifugal drum. The hat felt is thereafter subjected to treatment with a synthetic plastic acting as binding agent in the form of a solution, dispersion or emulsion. The treatment can be effected in an immersion process or, e.g. also in a spraying process. After this treatment, the hat felt is squeezed in a roller squeezing device, the pressure of the rollers appropriately being adjusted according to the desired squeezing effect. The hat felt thus squeezed and impregnated with the synthetic plastic acting as binding agent can, if desired, be subsequently heated by means of steam and applied over a metal form which is somewhat larger than the conical support form on which the hat felt was formed, so that a slight stretching of the felt is effected. The hat felt can thereafter be dried at about 70 C. and then hydraulically pressed under heavy pressure and at a medium temperature. The hat felt may, however, also be subjected for about 5 minutes to a temperature of about 100 C.-170 C., thereby effecting curing of the synthetic plastic present in the hat felt.

The following specific examples are intended to illustrate the invention in greater detail. Any other mixtures known to the man skilled in the art may naturally be used instead of the following mixture of synthetic substances.

Example 1 A mixture of rabbit or other animal hairs and polyacrylonitrile fibers is used in a ratio of 70:30. This mixture is plyed in conventional manner, thereafter-so far as this is desiredslightly felted or matted and possibly dyed. A final stiffening with a binder fluid of the follow ing composition is then effected:

300 g./l. of a 43% dispersion of a polymer of acrylic acid butyl ester, butadiene and 5% of acrylamide,

50 g./l. of a aqueous solution of polyacrylamide,

30 g./l. of a 50% aqueous solution of trimethylol melamine and 3 g./l. of ammonium chloride.

4 After the impregnation, the felt is freed of excess fluid by squeezing, dried at C. and then heated for 5 minutes at C.

Example 2 A felt prepared as in Example 1 is impregnated with a fluid of the following composition:

470 g./l. of a 37% dispersion of a polymer of acrylic acid butyl ester, 5% of acrylamide and 5% of methacrylamido-N-methylol methyl ether and 4 g./l. of ammonium chloride.

The subsequent treatment is effected in the same manner as in Example 1.

What we claim is:

1. A method for producing hat felt which comprises mixing rabbit hairs and polyacrylonitrile fibers, felting and pre-forming the mixture of fibers, applying to the thusformed product a mixture comprising (a) an aqueous dispersion of a polymer of acrylic acid butyl ester, acrylamide, and methacrylamido-N-methylol methyl ether and (b) ammonium chloride in solution in the aqueous phase, and then heat-curing the resultant product, thereby obtaining a permanently formed hat felt.

2. A hat felt comprising a mixture of rabbit hairs and acrylonitrile fibers bonded with a thermoset terpolymer of acrylic acid butyl ester, acrylamide and methacrylamido- N-methylol methyl ether.

References Cited UNITED STATES PATENTS 2,936,512 5/1960 Casse 28--72.3

EARL M. BERGERT, Primary Examiner W. E. HOAG, Assistant Examiner US. Cl. X.R.