US3037262A - Shed-proof napped blanket fabric - Google Patents

Description

June 5, 1962 F. T. SPENCER 3,037,262

SHED-PROOF NAPPED BLANKET FABRIC Filed Jan. 18, 1961 United States Patent Ofiice 3,fi37,262 Patented June 5, 1962 3,037,262 SHED-PROOF NAEPEE) BLANKET FABREC Francis T. Spencer, Biddeford, Maine, assigner to Pepperell Manufacturing Company, Boston, Mass, a corporation of Massachusetts Filed Jan. 13, 1961, Ser. No. 83,538 6 Claims. (Cl. 288t)) This invention relates to napped or similar fabric, more especially blanket cloth having certain useful characteristics, some of which, in particular, resistance to shedding, have been recognized heretofore as desirable, but which have not been commercially attainable, at least as respects fabric wherein the nap is predominantly of certain specific materials.

For the attainment of the above desired characteristics, it has heretofore been proposed to treat the nap layer of the fabric as, for example, by spraying it with a liquid of a kind such as chemically or physically to change the character of the individual fibers; to cause adjacent fibers, where they contact, to coalesce; or to form a coating upon the individual fibers which may or may not cause the fibers to adhere to each other, and then allowing or causing the treating medium to dry, cure or set. However, such modes of treatment have in many cases had the ultimate result of making the fabric dense and felt-like; of decreasing the loft of height of the nap; or of producing a nap having a crust-like surface having a distinctly different appearance and/ or feel from that which is demanded in the intended field of use of the material.

Some of the substances which have been employed in treating napped material are found among the synthetic resins while others are solutions of certain inorganic salts. Thus, as flame-retardant materials for cotton, certain polymers made by reacting tris (l-aziriciinyl) phosphine oxide, referred to as APO, or tris (l-aziridinyl) phosphine sulfide, referred to as A'PS, with tetrakis (hydroxymethyl) phosphonium chloride, referred to as THPC have been employed. As water repellants for cotton, substances such as ODI (octadecyl isocyanate) have been empolyed, and for crush-resistance the so-called Rohnite resins (which are water-soluble urea formaldehyde resins), and the socalled Safe-Te-Set resins (which are cyclic urea resins), which are applied in water solution, have been used.

While the method of preparing the fabric herein claimed may be found useful in the treating of napped or similar fabrics for other purposes, the invention herein disclosed relates specifically to a novel blanket cloth characterized by its unusual resistance to the shedding of nap during customary use, or as the result of laundry treatment but which, at the same time, is soft and drapeable, lofty in feel and has the pleasing appearance of customary untreated napped blanket cloth. While herein the term napped fabric or napped blanket cloth is employed for convenience, it is to be understood that this term is not to be restricted to a fabric having a layer of upstanding fibers such as produced by passing a woven fabric through a conventional napping machine, but is to be considered as broadly inclusive of high-pile fabrics such as plushes and artificial furs made from textile materials. However, the invention is herein described by way of specific example as applied to the manufacture of a non-shedding household blanket.

Since certain of the synthetic fibers have, in recent years, been widely adopted in blanket manufacture, and because some of such fibers are very slippery and more prone to shedding when constitutin a nap than the natural fibers, interest in the reduction of shedding of blanket fibers has been intensified. Thus, for example, it has been proposed to decrease shedding of a blanket wherein Orion constitutes a substantial percentage of the nap, first by treating the napped fabric by spraying it with certain chemical substances and then subjecting it to heat, whereby the chemical so reacts with the material of the nap fibers as to soften the surface of the fiber which has been wet by the chemical, with the result that, when the fabric is allowed to cool, adjacent fibers coalesce at their contact point thus providing an interlock which substantially lessens the loss of nap during use. On the other hand, when a like treatment has been applied to blanket material where the nap is predominantly cellulosic, for example rayon, although the insulating value and wearing quality of the blanket are not adversely affected and loss of nap is somewhat reduced, the material, as heretofore so treated, shows a strong tendency to lose its original lofty appearance. Purchasers are greatly influenced by the appearance and feel of a blanket and thus would have a tendency to select an untreated blanket rather than that which has been treated. Moreover, since the cellulosic blanket, prepared as above, does shed nap to some extent, it would not be premissible to mark such a blanket as shed-proof.

A principal object of the invention is to provide a truly shed-proof blanket whose nap is predominantly of cellulosic fiber, for example rayon; which sulfers no apparent loss of loft by reason of the treatment to which it is subjected in making it shed-proof, and whose feel and appearance, as compared with a freshly napped blanket, are not substantially modified, or may even be improved. A further object is to provide a blanket fabric which is substantially shed-proof and wherein the nap fibers are individually coated and adhesively bonded together and are substantially perpendicular to the plane of the main body of the fabric. A further object is to provide a substantially shed-proof napped fabric wherein adjacent n-ap fibers are bonded together by a material other than the substance of the fiber itself, and wherein individual nap fibers occupy approximately the same relative positions as they did in the fabric at the completion of the napping operation. A further object is to provide a shed-proof blanket which is free from any chemical substance which might be harmful to a small child who might chew or suck the fabric. A further object is to provide a napped blanket fabric wherein the nap is predominantly cellulosic and which is shed-proof.

A further object is to provide shed-proof blanket cloth which is soft and drapeable and which comprises a body portion of conventional weave and which has a layer of nap fibers projecting from one side at least of the body portion, the nap fibers being predominantly cellulosic and the body portion possessing substantially the same characteristics as when freshly woven, while the nap is substantially the same, with respect to appearance, color, feel and loft, with the nap fibers predominantly upstanding, as when newly napped, and wherein the nap fibers have the same chemical characteristics which they had in the fabric as woven, and comprising means where individual nap fibers are so permanently bonded togethe as substantially to reduce the shedding of the nap when the fabric is exposed to conditions simulating those of blanket fabric under ordinary conditions of use. A further object is to provide shed-proof blanket cloth which is soft and drapeable and which comprises a body portion of woven cellulosic material and a layer of nap fibers projecting from one side, at least, of said body fabric-the nap fibers being predominantly of rayon and the body portion retaining substantially the same characteristics as when newly woven, while the nap fibers are substantially the same with respect to appearance, feel and loft as when freshly napped, and wherein individual nap fibers are coated with an acryl- O ic polymer which so bonds them together as substantially to prevent shedding of the nap during the use of the blanket cloth.

answer;

Other and further objects and advantages of the invention will be pointed out in the following more detailed description and by reference to the accompanying drawings wherein:

FIG. 1 is a diagrammatic elevation or flow-sheet, illustrative of the successive steps in the process; and

FIG. 2 is a fragmentary vertical section, to larger scale than FIG. 1, illustrative of the step of raising the nap fibers while they are still Wet with a treating liquid.

During the research which resulted in the present invention, it was discovered that when napped fabric, wherein the nap was predominantly of acrylic material such, for example, as Acrylan, was first sprayed with a certain acrylic emulsion in water dispersion so as to coat the nap fibers, and then the fabric was baked at a temperature of approximately 300 F., a coating was formed upon the nap which permanently bonded adjacent fibers toeach other to an extent such as substantially to reduce the shedding of the nap when the fabric was exposed to conditions simulating those of blanket fabric under ordinary conditions of use. The chemical employed did not alter the chemical structure or physical properties of the individual fibers and since, after heat-treatment, it was completely insoluble in Water, the finish thus provided became a permanent part of the blanket and continued to oppose shedding throughout the useful life of the fabric. It may be noted that acrylic fibers have a natural resiliency, not possessed by cellulosic fibers and are hydrophobic in nature, and because of these two qualities, treated acrylic blankets are not altered perceptibly in appearance as compared with the untreated fabric and retain their original loft and resilience so that sales appeal is not lessened by reason of this particular treatment.

Experiments with blanket cloth made predominantly of cellulosic fibers and subjected to the above treatment, are also, to a certain extent, shed-resistant. However, it was observed that blankets, so treated, showed a tendency to lose the initial lofty appearance and feel of the untreated fabric as it exists when the initial napping has just been completed. Such a blanket, while useful for its intended purpose, did not have an appearance such as to recommend it to the puchaser. In the effort to make a cellulosic nap fully shed-resistant, it was proposed to modify the above treatment by increasing the concentration of the chemical. This was carried out to the point at which a crust of chemical was formed on the opposite faces of the blanket. While the resultant fabric was actually shed-proof, it had lost loft-that is to say, the thickness of the nap layer was less than in the untreated fabric, while the presence of the crust imparted an appearance and feel suggestive of materials heretofore proposed for blankets, but which are in the much lower price range as compared with blankets of nappcd woven textile fabric. Attempts to dispose of this crust so as to restore the feel and appearance of the original nappcd fabric, as by breaking up or otherwise modifying or removing this crust, after once having been formed, were wholly unsuccessful. Even though the treated material were again passed through the napping machine, the resultant fabric did not have the same appearance as when first nappcd and, moreover, the action of the napping machine was such as to break the bond which had been provided between the nap fibers, so that the net result was to produce a material which was inferior to the original untreated nappcd fabric. The desired results were eventually attained by first spraying the nappcd material with the selected chemical, as above described, but at a concentration lowe than such as would form a crust; then, while the material was still wet with the spraying material, raising the map to its original height or even higher, and then, without applying pressure (as by passing the material between rollers), subjecting it to a heat-treatment whereby the nap fibers, in their raised position, were bonded together by the coating chemical so that the blanket became shed-proof and had a feel and appearance, but little different and, if anything with a higher loft and softer feel than a nappcd blanket which has just passed through the napping machine.

Referring to the drawings, the character N indicates, in a diagrammatic manner, a napping machine of ordinary type, wherein the woven cloth C passes betwccn rolls It and 11, clothed with the usual pin-covered napping fabric which, by engagement with the yarns forming the initial woven cloth, raises some of the constituent fibers of the yarns to form a nap on the opposite surfaces of the body of the cloth. This cloth C with nap at its opposite surfaces, is then desirably temporarily stored in any convenient way in readiness for the novel treatment according to the present invention. For example, the cloth may be laid in folds upon a truck, or in a box or other portable container and, in this condition, moved to the vicinity of the treating apparatus. As diagrammatically illustrated in FIG. 1, the treating apparatus desirably comprises a conventional tenter frame T having the customary parallel, constantly travelling chains (not shown), provided with pins or clamps which engage the opposite selvage edges of the fabric and hold the fabric under transverse tension while moving it along progressively, in the direction of the arrow A, with its nappcd surface in a horizontal plane, and out of contact with solid rollers, or any other elements such as would tend to crush or compress the nap. As the fabric is so moved, spray heads S, of any suitable type, and which are supplied with the coating material under pressure, deliver this matcrial as a liquid spray against the opposite faces of the fabric. One material which has been found eminently suitable for the purpose is an aqueous dispersion of an acrylic polymer known to the trade as Rhoplex HA8, which is made by the firm of Rohm & Haas of Washington Square, Philadelphia 5, Pennsylvania. Materials of this class are described in the Supplement to the 1953 edition of Handbook of Materials and Trade Names, (published by industrial Research Service, Dover, New Hampshire), under the generic name Rhoplex Emulsion, an aqueous dispersion of acrylic polymers which, when deposited from dispersion in water, forms a transparent film.

In accordance with the present invention, the dispersion of this chemical in water is within the range of 93% to 93 /2% water and from 1 /2% of chemical to 7% chemical. However, it is contemplated that this range may be extended slightly in either direction. As applied in this dilution, the chemical is not appreciably sticky, so that it flows freely and is readily absorbed by the nap layer. The liquid dispersion is applied to the cloth within the range of from 10% to 15% by weight of liquid to cloth and, here again, the range may be varied slightly up or down.

The fabric, afte having een sprayed in this manner, is advanced (FIG. 1) between two sets 12 and 13, respectively, of freely rotatable rollers one set of rollers being above the cloth and the other below it and with their axes so arranged that the cloth must follow a sinuous path in passing between the upper and lower rolls. Rolls of 4 inches, extreme outside diameter, have been found useful for the purpose, although it is contemplated that rolls of other sizes may be employed, it being advantageous to use rolls of such size and so arranged as to provide a substantial period of contact of the cloth with the rolls. These rolls, as illustrated diagrammatically in FIG. 2, have cylindrical cores covered, for example, with mapper-roll cloth, using pins P of the elbow type having a 45 bend, but it is contemplated that other types of pin may be found useful. Upper and lower rolls, as shown at 12a and 13a in FIG. 2, are so arranged that the points of their pins are directed toward the oncoming fabric-it being noted that the fabric is continuously advanced by the chains of the tenter frame in the direction of the arrow A (FIG. 1). The rolls are free to turn and are turned only by the frictional drag of the cloth.

As the cloth progresses, the tips of the pins enter the nap layer and so agitate the nap as to induce the liquid to enter more deeply into the nap layer. Then, as the rolls turn, and the angle of the pins changes, in relation to the plane of the cloth, they tend to raise the nap, that is, to move te pile fibers into perpendicularity relatively to the body of the fabric, resulting in a smooth even surface and a loftier nap than results from the conventional napping operation.

After leaving the sets 12 and 13 of rolls, the fabric is advanced through a housing H having therein any suitable type of heating means here illustrated as infrared lamps L-the treating chamber being long enough so that the liquid carrier for the chemical is gradually evaporated. A minimum temperature in the heating chamber of approximately 250 F. is useful for the purpose, although it is preferred to increase the temperature to approximately 300 F. to speed up the operation. As the material C travels through the heating zone, and the water evaporates, the chemical concentrates and first forms a sticky coating on the nap fibers so that adjacent fibers, where they contact, adhere to each other, and then sets to form a permanent bond.

While the above mode of treatment is particularly useful for the treatment of rayon or other cellulose fibers, the raising of the nap while wet with the chemical, appears to improve the character of acrylic blankets, or other napped materials, beyond that which is the result of previous methods of treatment for the prevention of nap shed-ding (whether by the use of the above acrylic polymer emulsion, or other chemicals).

The result of this treatment not only makes the material truly shed-proof, but appears to impart to the mapped fabric a quality which has not heretofore been obtained by any previous method and it is contemplated that any napped fabric thus treated will have a loft and appearance superior to that of fabric which has been freshly napped but not otherwise treated.

While one desirable method of producing the novel fabric of the present invention and instrumentalities whereby it may be practiced has herein been described by way of example, it is to be understood that the invention is broadly inclusive of any fabric within the scope of the appended claims regardless of the apparatus employed in its production.

I claim:

1. A shed-proof blanket cloth which is soft and drapeable and which comprises a body portion of woven fabric having a layer of nap fibers projecting from one side, at least, of the body fabric, the nap fibers being predominantly cellulosic, said blanket cloth being substantially the same with respect to appearance, feel, color and loft, and with the nap fibers predominantly upstanding, as when freshly napped, the nap-forming fibers having the same chemical characteristics which they had in the fabric as woven, individual nap fibers comprised in said layer being coated witha material which provides -a permanent bond whereby adjacent nap fibers are permanently united so as substantially to prevent the shedding of the nap during the use of the blanket cloth while the body fabric is substantially free from said coating material.

2. Blanket cloth according to claim 1, wherein the body fabric is predominantly cellulosic and the coating material, which coats the nap fibers, is an acrylic polymer.

3. Blanket cloth according to claim 1, wherein the nap fibers are predominantly rayon and the coating material is Rhoplex HA-8.

4. Blanket cloth according to claim 1, wherein the coating upon the individual nap fibers is such as results from the evaporation of an acrylic polymer from a water dispersion in the approximate proportion of 93% water and 7% resin.

5. Blanket cloth according to claim 1, wherein the fabric body has a layer of nap at each side, respectively, and wherein fibers, comprised in each respective layer, are permanently bonded together by an adhesive coating.

6. A soft, d-rapeable, shed-proof blanket cloth com prising a woven body fabric having a layer of nap fibers projecting from one side, at least, of the body fabric, the nap fibers being predominantly of rayon, the body fabric retaining substantially the same characteristics as when newly woven, and the nap layer being substantially the same, with respect to appearance, feel and loft of nap and the nap fibers being predominantly upstanding, as when freshly napped, the nap-forming fibers having the same chemical and physical characteristics which they had in the fabric as woven, the individual nap fibers being coated with an acrylic polymer which so permanently bonds them together as substantially to reduce the shedding of the nap when the fabric is exposed to the usual conditions of use while the body portion of the fabric is substantially free from said coating material.

References Cited in the file of this patent UNITED STATES PATENTS 2,329,651 Powers et al. Sept. 14, 1943 2,590,713 Libbey Mar. 25, 1952 2,639,240 Ehle May 19, 1953 2,641,045 Meister et al. June 9, 1953 2,656,586 Cowie et al. Oct. 27. 1953

Claims (1)

1. A SHED-PROOF BLANKET CLOTH WHICH IS SOFT AND DRAPEABLE AND WHICH COMPRISES A BODY PORTION OF WOVEN FABRIC HAVING A LAYER OF NAP FIBERS PROJECTING FROM ONE SIDE, AT LEAST, OF THE BODY FABRIC, THE NAP FIBERS BEING PREDOMINANTLY CELLULOSIC, SAID BLANKET CLOTH BEING SUBSTANTIALLY THE SAME WITH RESPECT TO APPEARANCE, FEEL, COLOR AND LOFT, AND WITH THE NAP FIBERS PREDOMINANTLY UPSTANDING, AS WHEN FRESHLY NAPPED, THE NAP-FORMING FIBERS HAVING THE SAME CHEMICAL CHARACTERISTICS WHICH THEY HAD IN THE FABRIC AS WOVEN, INDIVIDUAL NAP FIBERS COMPRISED IN SAID LAYER BEING COATED WITH A MATERIAL WHICH PROVIDES A PERMANENT BOND WHEREBY ADJACENT NAP FIBERS ARE PERMANENTLY UNITED SO AS SUBSTANTIALLY TO PREVENT THE SHEDDING OF THE NAP DURING THE USE OF THE BLANKET CLOTH WHILE THE BODY FABRIC IS SUBSTANTIALLY FREE FROM SAID COATING MATERIAL.

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