US 3399642 A
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Description (OCR text may contain errors)
Sept. 3, 1968 G. o. ErcHlsoN ET AL 3,399,642
PROCESS FOR PREVENTING SEAM PUCKER Filed March 30, 1967 /Cyy/ ATTORNEYS nted States Patent PROCESS FOR PREVENTING SEAM PUCKER Gibson 0. Etchison, River View, R. Allen McDaniel, Fairfax. and George E. Hines, River View, Ala., assignors to West Point-Pepperell, Inc., West Point, Ga., a corporation of Georgia Filed Mar. 30, 1967, Ser. No. 627,204 3 Claims. (Cl. 112-262) ABSTRACT F THE DISCLOSURE A process for preventing fabric puckering along a line of stitches in a fabric article. A nonwoven fabric is sewed to the back of the fabric in said article by placing a line of stitches through the upper and lower surfaces of both the fabric and the nonwoven fabric. The nonwoven fabric is permanently collapsible to a small thickness and is collapsed when the article is pressed. This generates slack in the thread in the line of stitches, permitting the thread to shrink in laundering without puckering the fabric.
The present invention relates to garments and more particularly to a garment construction which prevents puckering during washing and use.
There is a tendency for the fabric in various garments to gather or pucker during washing. This is observed along a line of stitching, the fabric being puckered between stitches. The puckering is known to be caused by shrinkage of thread used to sew the garment, that is the longitudinal shrinkage of the thread between stitches is greater than that of the fabric. In sorne cases, the thread may break, which releases the pucker but is just as undesirable. Thread shrinkage is difiicult to avoid because the thread may be stretched when the seam is sewn.
The problem is especially serious in permanent press garments. These garments are made of fabrics which have been impregnated with an unpolymerized resin such as urea formaldehyde which is cured after the garments are made. They have the important advantages of retention of creases pressed in during manufacture and resistance to formation of other creases. They also have excellent dimensional stability. Because of this dimensional stability, they do not shrink substantially during subsequent use, and laundering and thread shrinkage during laundering causes objectionable puckering.
A principal object of the present invention is to prevent puckering in garments caused by shrinkage of sewing thread, especially in permanent press garments, Briefly stated, this is accomplished by producing slackness in the thread when the garment is pressed during manufacture. A collapsible interlining is laid against the fabric where it is to be stitched, and the line of stitches is sewed through the fabric and the interlining. When the garment is pressed, the interlining collapses to a fraction of its initial thickness which reduces the thickness of the garment through which the thread is sewed. This produces a slackness in the thread. Then, when the thread shrinks during laundering, it merely tightens against the garment without distorting it.
The collapsible interlining used in accordance with the present invention is a nonwoven fabric containing a binder. A nonwoven fabric is a web or mat of textile fibers not spun into yarn, deposited in more or less ordered array and held together at spaced points along the fibers, that is at some of the points where the fibers cross. The nonwoven fabric used in the present invention initially is an open mat of fibers of substantial thickness which has a degree of stiffness imparted by the binder. When sufficient pressure is applied against opposite surfaces, the nonwoven fabric is collapsed by rearrangement of the fibers. This operation is carried out with heat which causes the binder to adapt to the collapsed arrangement of the fibers and fix them in their new positions.
Several systems of binding fibers in nonwoven fabrics are known. One type comprises thermoplastic polymers. The polymer may be applied from a latex or solution and tends to collect at junction points of fibers as well as forming a sheath around the fibers in certain cases. If the fabric is heated during shaping, the thermoplastic polymer ows and adapts to the new configurations of the fibers. On cooling, the polymer rehardens and preserves the shape of the web.
A second type of binding is essentially an improvement of the first. Thermoplastic polymers are used which are curable (i.e. cross-linkable). During hot shaping, the binders fiow but as heating continues they become crosslinked. In this condition, they fix the fiber configurations and resist subsequent deformation, even on application of heat.
A third type of binding is based on the use of thermosetting resins such as urea, phenol and melamine-formaldehyde pre-condensates. While these are similar to the curable thermoplastic polymers in being capable of curing when heated, the most common types are not initially high polymers. Therefore, they may not stiften the webs when initially applied to the same extent as curable thermoplastic binders.
A fourth binding system is based on softening the peripheries of the fibers. If the fibers are thermoplastic, they may be caused to adhere to each other by heating to the softening temperature. Softening also can be accomplished with so-called latent solvents. A typical illustration is an aqueous solution of zinc chloride as a binder for nylon, Concentrated zinc chloride solutions dissolve nylon, especially at elevated temperatures, but dilute solutions do not. Thus, a dilute solution of zinc chloride is applied to a nylon web. During subsequent heating, a part of the water evaporates, leaving a more concentrated solution. This dissolves and softens the surfaces of the nylon fibers making them tacky. As heating continues, the rest of the water evaporates, removing the solvent, and the dissolved nylon rep-recipitates. Consequently, the fibers stick together and are then permanently adhered as the nylon rehardens.
Curable thermoplastic binders are preferred for the present invention. They impart stiffness to the nonwoven fabric when initially applied, and this stiffness may be improved by a partial curing before the nonwoven fabric is stitched into a garment. When the nonwoven fabric is sewed into a garment, the binder, even if partially precured, is still sufiiciently thermoplastic to permit it to fiow and adapt to the new configurations of the fibers. Then it is cured (or its curing is increased) when the garment is pressed.
It is desirable that the initial nonwoven fabric be relatively stiff. If it were soft and easily compressed, the sewing thread lwould compress it too easily. It is difficult to prevent the thread from partly compressing the nonwoven fabric, but it is necessary that the thread not collapse the nonwoven fabric to its ultimate thickness. Generally, the thickness of the nonwoven fabric is reduced somewhat at points where the stitches pass through it but much less between those points. The applied binder imparts the necessary stiffness to the nonwoven web.
Numerous fibers may be used in manufacturing the nonwoven fabrics. Natural fibers may be used such `as cotton and other cellulosic fibers, wool and silk. Synthetic fibers also may be used, for example rayon, various polyamides having amide linkages connecting recurring units in a polymer chain such as polyhexamethylene adipamide (nylon 66), polycaproamide (nylon 6), polyundecanoamide (nylon 11) and various copolymers, various polyesters having ester linkages connecting recurring units in a polymer chain such as polyethylene terephthalate and terephthalate-isophthalate copolymers, acrylic fibers, i.e., polyacrylonitrile, modacrylics, i.e., copolymers of acrylonitrile, eg., with vinyl chloride, Saran fibers, i.e., polyvinylidene chloride and its copolymers, eg., with vinyl chloride, polyolelins such as polyethylene and polypropylene, cellulose esters such as cellulose acetate, and gloss fibers.
The fibers may be formed into a nonwoven fiber web by any conventional procedure. For example, the fibers may be floated or otherwise laid onto a moving screen through which suction is applied. A web also may be formed by a card, or similar apparatus, and web thickness can be increased by cross-laying a web in known manner. Normally it is desired that the thickness of the web, before application of binder materials, will be about 0.020 to 0.500 inch with a liber weight of about 0.5 to 4.0 ounces per square yard. The web weight will be increased, of course, by the add-on of binder.
The binder preferably is applied from an aqueous latex of polymer particles, although solutions and other binder applications also may be used. An aqueous latex has the advantage of high solids content and avoiding the expense and technical problems associated with organic solvents.
Liquid binder materials, such as a latex, may be applied by any conventional means, for example by immersion or spraying. The add-on of binder solids should preferably be about to 200% by weight of the dry fibers.
Any liquid associated with the binder is removed, e.g., by evaporation. Up to this point, the fabric preferably is not calendered or squeezed since these operations tend to reduce the thickness of the material and therefore reduce the amount it collapses when used. It also is not heated sufficiently to cure the binder completely, although a partial precure may be useful. When the impregnated material is dry, it is relatively stiff and has a weight of 0.5 to 4.0 ounces per square yard and its thickness is about 0.020 to 0.225 inch.
Numerous curable thermoplastic binders suitable for practicing the present invention are already known. The binder should be one which is capable of softening and curing at a lower temperature than the fibers, if the fibers are themselves thermoplastic. For example, acetate sticks at 350-375 F. and is heat sensitive, like nylon and Daeron in the range 400-480 F. Polyurethane sticks at temperatures as low as 347 F.
Numerous such resins are readily available commercially as, for example, Rhoplex E-32 and Rhoplex HA-16, both of which are self-curing acrylic latices.1 These can be cured at G-250 F. which permits their use on a wide variety of fibers. The latter have the advantage of being thermoplastic until they are cured. Consequently, they are able to adapt to the movements of the fibers caused by the compressive shrinkage treatment, and then, by being cured, they tix the fibers after they have been rearranged. Other elastomer latices may be used, for example, Hycar 2600X83 :and the natural rubber latex formulation having the composition:
Percentage-dry basis Natural rubber latex 90.70 Setsit No. 5 (dithiocarbonate accelerator) .30 Sulfur 1.80 Zinc oxide 2.70 Aquablak B (carbon black) 4.50
Each ingredient is dispersed in water and added to the latex. Water is added to adjust the formula to the percent dispersion required, for applications to the fiber web, e.g., 20% solids aqueous dispersion.
lDetailed descriptions of these latices have been publishedy eg., in the book Rhoplex Acrylic Emulsion for the Textile Industry. copyright 1962, Rohm and Haas Company. Thus Rhoplcx IIA-10 is characterized by having a. solids content of %10570. a pil ot' 2.730 and a specific gravity of 1.00. '.lhe value Tg (transition temperature) is 30 C and tho minimum film-forming temperature is 34 C.
The above-described nonwoven fabric is sewed into a garment by hand or machine. For example, it may be sewed under the box center pleat of a mans shirt, in a shirt collar or in a shirt cuff. In any other garment or other kind of fabric article, where there is a seam or other line of stitching, the stitches are sewed through the garment and the nonwoven fabric.
The practice of the invention is illustrated by the drawing in which:
FIG. l is a partial view of a mans shirt showing a box center pleat embodying the invention;
FIG. 2 is a cross-section along line 2-2 of FIG. l;
FIG. 3 is a cross-section similar to FIG. 2 showing the box center pleat being collapsed; and
FIG. 4 is a cross-section similar to FIG. 2 showing the finished box center pleat.
The shirt of FIG. l is of conventional construction and includes a collar 1 and shirt body 2, a front 4opening 3 and a pocket 4. Along the edge of the front opening there is a box center pleat 5 having button holes 6 through it.
The box center pleat is a single layer of fabric 1S whose vertical edges 7 and 8 are turned under the single layer of fabric in flaps 16 and 17 to lie against the shirt body. Two vert-ical lines of stitches 9 and 10 are sewn through the box center pleat and the shirt body 2.
Between the layer of fabric 15 and t-he shirt body there also is placed a layer of nonwoven fabric 11 of the type described above. The lines of stitches 9 and 10 are sewed through the nonwoven fabric 11.
After the shirt is sewn, it is pressed in conventional manner, for example by members 12 and 13 shown in FIG. 3, which may be heated by electrical heaters not shown. The nonwoven fabric is heated brieiiy to allow the binder to flow and cure, and then the members 12 and 13 may be released. The garment cools, and the binder is stiff. Curing may continue for a week or two at a slower rate during storage. The collapsed nonwoven fabric, containing cured binder, then is substantially permanently set in its collapsed thickness.
As the nonwoven fabric collapses, the length of thread in stitching 9 and 10 is not changed significantly Therefore, the thread is slack, as represented at 14 in FIGS. 3 and 4. If the thread shrinks during laundering, it is not likely to pull the fabric layer 15 into a puckered shape.
The temperature and pressure used are those ordinarily used in pressing a garment. The exact pressure employed 1in the press is dependent on the temperature and the time required to reduce the nonwoven fabric to the thickness desired. Normally, the higher the temperature, the less pressure required and vice versa. Typical temperatures are 280 to 450 F. and typical pressures are up to about l0 p.s.i., preferably less than 3 p.s.i. The thickness after Collapse should be about 10 to 30% of the original thickness. Pressing is continued for the time necessary for the binder to liow and cure, e.g. at least 5 seconds.
The following example illustrates the practice of the invention:
A shirt of the type illustrated in FIGURE l was made of broadcloth having a weight of 4 oz. per square yard. The box center pleat is about 11/2 inches wide and has flaps each about 1/2 inch wide folded under.
Within the box center pleat is sewed an interlining 11 having the following characteristics:
Dry web: Polyester fibers about 3 denier and about 11/2 inches long, formed by air blowing into a web. The web is about 0.030 inch thick and weighs about l ounce per square yard. The web is impregnated with Rhoplex IIA-8 binder latex (about 46% solids) by imme'rsing it in the latex. Following impregnation the web is dried at room temperature and its weight has increased to about 2 ounces per square yard, its thickness remaining at about 0.030 inch.
The shirt is pressed with a press heated to 375 F. while applying about 3.3 psi. pressure. Pressure is maintained for l0 seconds and then released. When the shirt is cooled,
it was found that t-he nonwoven fabric is collapsed to about 0.005 inch thick and considerable slack lis generated in the sewing thread.
It will be appreciated that various changes may be made in selection of materials, details of construction and mode of operation without departing from the scope of the invention, as dened in the appended claims.
What is claimed is:
1. A process for preventing fabric puckering along a line of stitches in a fabric article which comprises sewing a nonwoven fabric to the fabric in said fabric article by placing said line of stitches through the upper and lower surfaces of both said fabrics, said nonwoven fabric being permanently collapsible to smaller thickness, and thereafter pressing said article along said line of stitches to permanently collapse said nonwoven fabric, thereby generating slack in the thread in said line of stitches, said slack permitting said thread to shrink in subsequent laundering without puckering the fabric along said line of stitches.
2. In a -fabric article, a fabric having a nonwoven fabric against said fabric and a line of stitches through the upper and lower surfaces of both said fabric and said nonwoven fabric, said nonwoven fabric being permanently collapsible to smaller thickness, the construction being such that said nonwoven fabric will be permanently collapsed by pressure applied to said fabric article, generating slack in the thread in said line of stitches, said slack permitting said thread to shrink in subsequent laundering without puckering the fabric along said line of stitches.
3. In a Afabric article, a fabric having a nonwoven fabric against said fabric and a line of stitches through the upper and lower surfaces of both said fabric and said nonwoven fabric, said nonwoven fabric having a weight of about 0.5 to 4.0 ounces per square yard and a thickness of about 0.020 to 0.225 inch and containing bers and about 5 to 200% curable thermoplastic binder by weight lof the fibers, said nonwoven fabric being permanently collapsible to about 10 to 30% of its thickness at a temperature of about 280 to 450 F. under a pressure up to about 10 p.s.i., the construction being such that said nonwoven fabric will be permanently collapsed by pressure applied to Said fabric article, generating slack in the thread in said line lof stitches, said slack permitting said thread to shrink in subsequent laundering without puckering the fabric -along said line of stitches.
References Cited UNITED STATES PATENTS 2,719,803 10/ 1955 Nottebohm 2.-243 XR RICHARD I. SCANLAN, JR., Primary Examiner.