EP0145168B1

EP0145168B1 - A method of forming and dyeing cushion articles

Info

Publication number: EP0145168B1
Application number: EP84307053A
Authority: EP
Inventors: Weir Sears I, Jr.; John E. Hostetler; William H. Hulsebusch
Original assignee: APPAREL FORM Co
Current assignee: APPAREL FORM Co
Priority date: 1983-11-03
Filing date: 1984-10-15
Publication date: 1989-08-09
Also published as: SE8405496D0; KR850003916A; DE3479309D1; MX159466A; AU3417484A; IE842571L; CA1238456A; ES537356A0; KR870000951B1; BR8405530A; SE8405496L; SE457720B; EP0145168A2; IE55887B1; ES8600160A1; IL73368A0; EP0145168A3; AU580564B2

Description

This invention relates to a method of making a cushion assembly which includes a foam cushion and a cloth covering, such as a cushion article for vehicle seating.
Upholstery coverings used in vehicle seating and elsewhere are conventionally produced by cut and sew techniques that result in high costs and unsatisfactory appearance in areas where the cloth is gathered or wrinkled.
The conventional method of making cloth articles begins with cutting the cloth, in the flat, into a number of pieces which are arranged according to a predetermined, often complex pattern. In order to minimize cutting costs, many layers of cloth are cut to the desired pattern at one time. This procedure, however, introduces size variations in the pieces, since the cutting knife may not hold precisely to the true pattern through the multiple layers of cloth. As a consequence, undesirable variations in the size and configuration of the final article occur. Conventional manufacture of cloth articles also requires that the cloth pieces of the pattern be joined or seamed, by sewing or welding, and darts are typically employed where necessary to shape the article. This is followed by pressing to improve fit and remove wrinkles. All of these steps are labor intensive and therefore expensive.
Because of inherent disadvantages in conventional fabrication of cloth articles, attempts have been made in the past to form these products by molding processes so that many of the inherent drawbacks of the present cutting and sewing or welding techniques could be eliminated. Molded cloth articles, for example, would be more economical to produce than those produced in accordance with traditional manufacturing techniques since the number of labor intensive steps employed in conventional techniques would be reduced, and consistency of sizing in the molded articles would bafar superior since size variations would be eliminated.
Molded cloth articles require far fewer seams and darts than traditionally manufactured products. This reduces the problem of opened and puckered seams, and greatly improves the article's durability, particularly after extended use and cleaning.
In addition, molded manufacture of cloth articles can provide improved appearance in the final product while at the same time reducing costs by minimizing both labor and the amount of material required to produce a finished product.
In EP-A-0072648 there is described a method of making garments, wherein a cloth shell is preformed from unfinished cloth and is placed onto a mold which is expanded to place the cloth shell under uniform tension, and the cloth shell and mold are immersed in a hot dyebath to dye the cloth and to heat-set the cloth so that it retains the three-dimensional shape of the mold when it is subsequently removed from the shell. The need for an expanding mold of the desired three-dimensional form and the need to place the cloth shell onto and remove it from this mold are inconveniences.
Two particularly important finishing steps typically performed at the mill are the dyeing and tentering of the cloth. The dyeing step in some instances involves the application of heat to the fabric, which in thermoplastic fabrics tends to set the intersections of the individual yarns. The tentering process involves the application of both tension and heat to set the intersections of the individual yarns. In method of EP-A-0072648, however, the fabric is set, dyed or tentered while in the general shape of the finished garment itself, significant advantages being obtained by working with goods which are not completely finished or greige goods which come off the loom or knitting machine prior to the application of any finishing processes.
In accordance with the present invention there is provided a method of making a cushion assembly comprising the step of constructing a cushion assembly including a foam cushion and cloth covering characterised in that the cloth covering is made from a flat blank of unfinished and undyed cloth, and while on the foam cushion the cloth covering is treated by being contacted with a dyebath, heated to a temperature above the cloth heat-set threshold and subsequently cooled to a temperature below the cloth heat-set temperature so that said cloth will be dyed and will retain the three-dimensional shape of said cushion, whereby the foam cushion of the final cushion assembly serves as a mold for the cloth covering during said treatment.
The present invention provides a dramatic departure and advance over the prior art methods for making cushion articles. It utilizes unfinished cloth which may be cut into a specially configured pattern or blank, and then forming, finishing and dyeing the cloth to completely finish and set its dimensional memory while using as a mold the foam cushion which is an essential part of the final product. The method of forming and dyeing .the cloth cover can produce cushion articles of excellent appearance and having covers which will reliably hold their color and original shape.
The dyeing can be performed at a temperature above the heat-set threshold of the cloth so that the cloth is dyed and simultaneously set. Alternately, the dye can be applied first and the heat then applied.
The cloth used in the practice of the present invention is preferably a one-piece flat "blank" or three dimensional shell constructed from the fewest possible number of pieces (preferably one) and joined by the least amount of stitching or welding possible. The shape of the cloth blank or shell generally follows the shape of the mold.
In an important embodiment of the invention, the cloth is an undyed polyester product which is dyed by first chemically treating the cloth to lower the fabric heat history characteristics and hence its ability to absorb dye and then dipping the cloth into a dye bath. However, in many instances the chemical treatment prior to dyeing is unnecessary, and hence not utilized. In this embodiment of the invention, the setting step may be performed at the same time the cloth is dyed by heating the dyebath above the heat set threshold of the polyester fabric.
The method of the present invention may utilize a wide variety of cloth materials, such as that woven or knitted from man-made or natural yarns or fibers, including nylon, polyester, acrylic, linen, cotton, rayon, wool, silk or blends of these fibers. The present invention is particularly well suited to woven fabrics, but its advantages apply to knitted fabrics as well. The invention involves the use of unfinished cloth. In the context of the present invention, "unfinished cloth" is intended to mean cloth that has not been subjected in the flat to the conventional treatments which impart to the cloth a permanent dimensional or shape memory or to set or fix the intersections of the yarn. For example, common finishing procedures such as tentering, crabbing, preshrink processes, chemical cross-linking processes and others well known in the art are not to be performed on the cloth prior to its use in practicing the present invention, to the extent that such procedures impart a permanent dimensional or shape memory to the cloth. On the other hand, "finished cloth" is intended to mean cloth that has been subjected to such permanent dimensional and shape memory procedures. Since unfinished cloth is employed in the process of the present invention, in practice, any thermoplastic synthetic cloth used will be exposed to its highest temperature during the molding and dyeing processes. Typically, the cloth used will have sufficient dimensional integrity to facilitate any prior cutting operations which may be required, but will otherwise have relatively little dimensional memory and the intersections of the yarn will not be permanently set or fixed.
In accord with a preferred embodiment of the invention, the cloth is subjected to a special treatment in the flat prior to use in the molding process in order to achieve a superior appearance free from even incidental wrinkling. In this preconditioning step, the cloth is lightly tensioned in the warp direction but left without tension in the fill direction and then heated to an elevated temperature, but one that is below the heat set temperature or conventional tentering temperature of the cloth. It has been found that this preconditioning of the cloth prior to the molding process eliminates any light wrinkling that might otherwise appear in the finished article.
The use of finished cloth - that which has been treated in the flat to impart permanent dimensional memory to the cloth - is unsuitable for a number of reasons. First, since the dimensional memory is set with the goods flat, the resetting of the cloth in contour is made more difficult, if not impossible. Second, finished goods have less inherent stretch than unfinished goods and, therefore, finished cloth is very difficult to place on a mold. And third, unfinished cloth, having yarn intersections that are free to move in both direction and dimension, can be properly orientated on the mold with the cloth distributed generally uniformly and without wrinkles, whereas finished cloth with relatively fixed yarn intersections prove difficult, if not impossible, to orientate without wrinkles on the mold.
In accordance with the present invention, the cloth is treated and dyed while on the mold constituted by the foam cushion to both color the cloth and to set the cloth, that is, to impart to the fabric a permanent shape and dimensional stability or memory. As mentioned previously, the dyeing and treating steps may be performed simultaneously or successively.
Heat setting of the cloth on the mold may be accomplished by passing the mold and cloth through an oven at a temperature sufficient to heat the cloth above its heat set threshold, which varies with the nature of the fabric. Alternatively, heating liquids or high pressure steam may be circulated around the mold and cloth in order to raise the temperature of the fabric above its heat set threshold.
It is also necessary in accord with the present invention to cool the cloth below the heat set temperature. Of course, the specific temperature to which the garment should be cooled will depend upon the particular cloth employed in practicing the invention. Also, in order to expedite the process, cooling may be enhanced by passing cooling fluids around the mold.
The present invention is directed to the dyeing of the cloth cover in combination with a heat treatment which will effect shape and dimensional memory in the cloth while it is on the foam cushion mold. Thus, in accord with the process of the present invention, the cloth cover is not only dimensionally set but is also dyed on the foam cushion in practice, greige goods have not been tentered or dyed may be cut into a properly shaped blank, mounted onto a suitable pre-prepared foam cushion and then dyed and set to provide a finished article. Any of the commonly used and conventional dyeing techniques known in the art may be employed in accordance with this aspect of the present invention. This approach has the advantage that the manufacturer may inventory the greige goods and then color the covers during manufacture to match the given demands of the marketplace. In addition, the specific cushion article will exhibit a greater color uniformity at the seam lines. The sequence of processing (i.e. dyeing and then setting, vice-versa or simultaneous) will depend upon the specific fabric used in the process and the processing capabilities of the manufacturer. Where the dyeing procedures employ temperatures above the fabric's heat-set temperature, the dyeing and heat-setting steps may be advantageously effected simultaneously.
Although any number of conventional dyes and dye baths may be used in the practice of the present invention, it has sometimes been found desirable in the practice of the present invention to chemically treat the greige goods to lower their heat history characteristics and hence to lower the temperature at which the fibers making up the greige good will absorb dye. It should be noted, of course, that such chemical pretreatment is not necessary in all cases and that dyeing of the unfinished cloth article can be accomplished without any such pretreatment.
Various facets of the practice of the method of the present invention will be described in the Examples below. These Examples are intended to be illustrative of the present invention, and not to be limiting in any way, and illustrate the application of the present invention to the manufacture of a cushion used in an automotive seat.

Example 1

A woven polyester/nylon, undyed cloth was prepared at the mill without any treatments that would impart a permanent set to the intersections of the yarn. This cloth was washed, bulked and dried, laminated to a film laminate including a polyurethane layer and an open-cell polyester foam layer, and then cut into a flat blank suitable for use as a seat cushion covering. The cloth blank was then drawn by vacuum into a mold and a polyurethane resin was poured into the mold and foamed, in situ, at relatively low temperature of approximately 120°-150°F (49°-65°C) to provide an integral cushion and covering. The cloth covered cushion was then removed from the mold and immersed in a dye bath at approximately 320°F (160°C) for about 120 seconds. During this dyeing step, the polyurethane foam cushion serves as a mold and the cloth covering is both dyed and set in the shape of the cushion. After dyeing, the cloth covered cushion was washed in a suitable solvent and dried. The resulting cushion exhibited excellent color and the cloth was permanently shaped in the configuration of the foam cushion.

Example 2

A polyurethane resin is poured directly into a mold and cured to form the desired shape of a foam cushion article such as a seat cushion. The foam thereby is poured into the mold in its liquid state and cold cured. The cured foam cushion is removed from the mold and a cloth covering is placed over the cushion. The covering is of unfinished and undyed cloth. The cloth preferably is preformed into a shell complementary to the three-dimensional shape of the cushion article. The shell is held onto the cushion by any of a variety of means such as mechanical means or adhesive. Or an open cell foam can be employed and vacuum applied to a vinyl backed covering. The cloth covering then is contacted with a dyebath and heated while on the cured foam cushion so that the cloth will be dyed and will retain the three-dimensional shape of the cushion. The cloth covering then is cooled while on the cushion. Here again, the cured foam cushion itself acts as a male mold to hold the fabric of the cloth in contour as it is dyed and set. The cloth covering is thereby heated to a temperature above the heat-set threshold and cooled to a temperature below the cloth heat-set temperature.
It can be seen in the Examples that the foam cushion acts as a mold in treating or setting the cloth covering while dyeing, and actually becomes part of the final product. Of course, the cured foam cushion must be sufficiently rigid to withstand the slight shrinking of the cloth during setting. It has been found that at least a 35 pound (16Kg) deflection rating is acceptable. In other words, an "indention load deflection" rating is determined by the weight required to deflect the foam one inch (2.54cm) when spread over a fifty inch (1.27m) area.
Those skilled in the art will appreciate the significant advantages attendant to the practice of the present invention. The resulting articles with few seams and no darts provides a new "look" and gives stylists new concepts to work with in designing new products. For the first time, undyed, unfinished woven cloth can be employed to form a completely finished cushion article in one process. Moreover, substantial savings can be achieved in the costs of manufacture by reducing inventory and substantially lowering the labor requirement. In addition, the final product exhibits an outstanding appearance, precise sizing and enhanced wearability.

Claims

1. A method of making a cushion assembly comprising the step of constructing a cushion assembly including a foam cushion and cloth covering, characterised in that the cloth covering is made from a flat blank of unfinished and undyed cloth, and while on the foam cushion the cloth covering is treated by being contacted with a dyebath, heated to a temperature above the cloth heat-set threshold and subsequently cooled to a temperature below the cloth heat-set temperature so that said cloth will be dyed and will retain the three-dimensional shape of said cushion, whereby the foam cushion of the final cushion assembly serves as a mold for the cloth covering during said treatment.

2. A method according to claim 1, wherein as a preliminary step to constructing the cushion assembly the foam cushion is prepared having the desired shape, and the cloth covering is applied over the prepre- pared cushion.

3. A method according to claim 1 or 2, wherein said dyeing is performed at a temperature above the heat-set threshold of the cloth to simultaneously dye and set the cloth.

4. A method according to any one of claims 1 to 3, wherein said dyeing is performed by dipping the cushion and the cloth covering into a bath containing the dye.

5. A method according to claim 1 or 2, wherein dye is first applied to the cloth covering and then the heat is applied.

6. A method according to one of claims 1 to 5, wherein the cloth covering is preformed into a shell complementary to the three-dimensional shape of the foam cushion.