Abstract:
A foam article comprising: a foam element; and a trim cover comprising a finished outer layer and an inner layer in contact with the foam element, the inner layer comprising a material having a kinetic coefficient of friction with respect to the foam element of less than about 0.75 when measured pursuant to ASTM D1894-00 using the conditions set out in GM9206P. The foam article is advantageously suited for use in a vehicular application such as a car seat (seat bottom, seat back and the like). The invention allows for the production of improved quality products while mitigating and obviating the need for additional material and/or labor costs.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     In one of its aspects, the present invention relates to a foam article. In another of its aspects, the present invention relates to a vehicular seat element. In yet another of its aspects, the present invention relates to a trim cover material particularly adapted for application to a foam element. 
     2. Description of the Prior Art 
     Foam articles are well known in the art. 
     Further, it is known to construct form articles from a foam element to which is applied a cover material that sometimes is termed as a “trim cover” in the art. The use of a trim cover applied to a foam element has gained widespread acceptance in the automotive industry. The trim cover can have a finished surface made of vinyl, cloth, leather and the like. The foam element is typically made from an isocyanate-based foam such as polyurethane. Of course, it is possible to construct the foam element from a cellular matrix material such as horse hair and the like. 
     In vehicular applications, it is common to employ foam articles in the seat of the vehicle. Typically a vehicular seat comprises two general elements. These are the seat bottom and the seat back. It is common for these elements to include a frame member coupled to the foam element and covered, at least partially, by the trim cover. 
     In recent years, the automotive industry has strived to improve the so-called “fit and finish” of all interior vehicular components, particularly the vehicle seats. In practice, this means striving to produce vehicular seats having narrower width channels or trenches and improving the overall appearance of the seat by creating a tighter fit between the trim cover and the foam element. A useful analogy is to consider striving to produce a vehicle seat where a trim cover fits the foam element “like a glove”. 
     As will be described below, the desire of the automotive industry to produce such improved foam articles has lead to a variety of problems during manufacture of the articles. Particularly, a significant amount of additional material and/or labour is required to produce such articles. In some cases, even with additional labour and/or material, it is still difficult to attain the goals set by the automotive industry. 
     Accordingly, it would be desirable to have a foam article which has an improved “fit and finish” appearance and can be made without significantly increasing the amount of labor and/or material costs required to produce the article. 
     SUMMARY OF THE INVENTION 
     It is an object of the present invention to obviate or mitigate at least one of the above-mentioned disadvantages of the prior art. 
     It is another object of the present invention to provide a novel foam article. 
     It is yet another object of the present invention to provide a novel vehicular seat element. 
     It is yet another object of the present invention to provide a novel trim cover useful for the production of a foam article such as a vehicular seat element. 
     Accordingly, in one of its aspects, the present invention provides foam article comprising: 
     a foam element; 
     a trim cover comprising a finished outer layer; and 
     a slip layer interposed between the foam element and the trim cover, the slip layer comprising a material having a kinetic coefficient of friction with respect to the foam element of less than about 0.75 when measured pursuant to ASTM D1894-00 using the conditions set out in GM9206P. 
     In another of its aspects, the present invention provides a vehicular seat element comprising: 
     a foam element; 
     a trim-cover comprising a finished outer layer; and 
     a slip layer interposed between the foam element and the trim cover, the slip layer comprising a material having a kinetic coefficient of friction with respect to the foam element of less than about 0.75 when measured pursuant to ASTM D1894-00 using the conditions set out in GM9206P. 
     In yet another of its aspects, the present invention provides a trim cover comprising a finished outer layer and an inner layer, the inner layer comprising a material having a kinetic coefficient of friction with respect to the a foam element of less than about 0.75 when measured pursuant to ASTM D1894-00 using the conditions set out in GM9206P. 
     Thus, the present inventor has discovered that it is possible to produce a foam article having improved “fit and finish” without the need to significantly increase the cost of labour and/or materials. More specifically, it has been discovered that the use of a trim cover with an inner layer comprising a material with a prescribed kinetic coefficient of friction with respect to the foam element allows for the use of tighter fitting trim covers resulting in the production of a foam article with improved “fit and finish”. The inner layer of the trim cover comprises a material having a kinetic coefficient of friction with respect to the foam element of less than about 0.75 when measured pursuant to ASTM D1894-00 using the conditions set out in GM9206P (the text of GM9206P is reproduced in the present application in the Appendix). The present foam article is particularly useful in vehicular applications such as in a vehicular seat element (e.g., one or both of a seat bottom and a seat back). Alternatively, the present foam article can be used in non-vehicular applications or in vehicular applications other than seat elements. The present foam article is particularly useful in applications where a foam element is completely or almost completely covered by a trim cover and the intent is to have a foam article with improved “fit and finish” or craftsmanship—e.g., an article having a tight fitting trim cover applied thereto. 
     The slip layer may be secure to the foam element or to the trim cover. Alternatively, the slip layer may be non-secure with respect to either of the foam element or trim cover. Preferably, the slip layer is secured to the trim cover. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Embodiments of the present invention will be described with reference to the accompanying drawings, wherein like reference numerals denote like parts, and in which: 
     FIGS. 1-4 illustrate production of a foamed article using a conventional approach; and 
     FIGS. 5-8 illustrate production of a preferred embodiment of the present foamed article. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Prior to describing the preferred embodiments of the present invention, a description of a prior art approach for producing a covered foam article is provided to facilitate understanding the problems associated with the prior art. 
     Thus, with reference to FIGS. 1-4, a conventional process for application of a trim cover to a foam element is set out. 
     Initially, a foam element  10  is provided. Foam element  10  may be produced in a mold or other conventional device. Typically, foam element  10  is made from an isocyanate-based foam such as a polyurethane foam. In the illustrated embodiment, foam element  10  is in the shape of a seat back typically used in the vehicular application. 
     As shown, foam element  10  has molded therein a U-shaped trench  15 . 
     In an initial step in the process, a spray dispensing device  20  (or other equivalent device) is used to dispense an adhesive  25  primarily in trench  15  of foam element  10 . 
     Next, a metal frame element  30  is moved in the direction of arrow A and placed in trench  15  of foam element  10 . 
     With reference to FIG. 2, once frame element  30  is position in trench  15  of foam element  10 , frame element  30  contacts adhesive  25  and is secured to foam element  10 . 
     With reference for FIG. 3, a trim cover  35  is disposed above the combination of frame element  30  and foam element  10 . It is known in the art to incorporate an inner layer (not shown) or slip sheet in trim cover  35 . This inner layer or slip sheet may comprise one or more of the following: foam, angel hair, polymer layers and the like. The inner layers or slip sheets used to date have a relatively high kinetic coefficient of friction with respect to foam element  10 . As shown, trim cover  35  is initially inverted so that the inner surface thereof is exposed. Next, trim cover  35  is lowered onto foam element  10  (having frame element  30  secured thereto) in the direction of arrow B. Once an upper surface  40  of trim cover  35  contacts foam element  10  trim cover  35  is “rolled” or otherwise moved such that an opening  50  of trim cover  35  is in alignment with a bottom portion  55  of foam element  10 . It should be noted that there are devices in the art which can perform the step illustrated in FIG.  3 . Since these devices are conventional, they will not be discussed further herein. 
     It is worthwhile to note that the use of adhesive  25  to secure frame element  30  to foam element  10  is done primarily for the purpose of securing frame element  30  in place during the covering step illustrated in FIG.  3 . In other words, the use of adhesive  25  is not required to secure frame element  30  to foam element  10  after production and installation of the vehicle seat. 
     With reference to FIG. 4, the covered foam article produced from FIG. 3 is shown. As illustrated, a portion C of foam element  10  protrudes from trim cover  35 . The reason for this is as follows. When it is desired to produce a covered foam article having improved “fit and finish” qualities, trim cover  35  becomes a much tighter fit with respect to foam element  10 . The result of using a conventional device to apply trim cover  35  to foam element  10 , as shown in FIG. 3, is protrusion of portions C from trim cover  35  (e.g., due to upper surface  40  of trim cover  35  not contacting an upper surface  45  of foam element  10  prior to “unrolling” of trim cover  35 ). Thus, it becomes necessary to employ one or more individuals to manually pull or finesse trim cover  35  in the direction of arrow D to finish the covering step and the production of the covered foam article. 
     Thus, it will be seen from the above description that the prior art technique of producing a covered foam article necessitates the use of extra materials (adhesive  25  to secure frame element  30  to foam element  10  during the cover step) and labour (one or more individuals to pull trim cover  35  in the direction of arrow D to cover protrusion of portion C of foam element  10 ). 
     With reference to FIGS. 5-8, a particularly preferred embodiment of the present foam article will be described. Thus, with reference to FIG. 5, there is illustrated a preferred embodiment of a trim cover  35   a  useful to produce the present foam article. Thus, trim cover  35   a  comprises an outer layer  60 , an intermediate layer  65  and an inner layer  70 . 
     Outer layer  60  of trim cover  35   a  is conventional and can be made of any desirable material such as cloth, vinyl, leather and the like. Intermediate layer  65  is optional. If present, intermediate layer  65  preferably comprises a foam, more preferably an isocyanate-based foam, most preferably a polyurethane foam. 
     Intermediate layer  65  may be secured to outer layer  60  in a conventional manner. For example, it is possible to secure intermediate layer  65  to outer layer  60  using an adhesive or similar material. Alternatively, it is possible to flame laminate, hot roll laminate, adhesive laminate or otherwise secure intermediate layer  65  to outer layer  60 . Inner layer  70  is provided and may be secured to intermediate layer  65  or the combination of outer layer  60  and intermediate layer  65  using any of the means discussed above. Alternatively, inner layer  70  may be sewn (or otherwise mechanically fastened) to the combination of outer layer  60  and intermediate layer  65 . 
     Inner layer  70  is comprised of a material having a kinetic coefficient of friction with respect to foam element  10  of less than about 0.75 when measured pursuant to ASTM D1894-00 using the conditions set out in GM 9206P (see the Appendix hereto). Preferably, inner layer  70  comprises a material having a kinetic coefficient of friction with respect to foam element  10  of less than about 0.73, more preferably in the range of from about 0.50 to about 0.73, more preferably in the range of from about 0.55 to about 0.73, more preferably in the range of from about 0.60 to about 0.70, more preferably in the range of from about 0.50 to about 0.65, when measure pursuant to ASTM D1894-00 using the conditions set out in GM 9206P. 
     Preferably, inner layer  70  comprises a polymer material, more preferably a polyester, a polypropylene or a mixture of a polyester and a polypropylene. It is possible to incorporate in the polymer material an additive or slip agent which serves to confer to inner layer  70  sufficient smoothness to provide a kinetic coefficient of friction with respect to foam element  10  of less than about 0.75 as set out above. 
     Preferably, inner layer  70  is constructed to be in the form of a non-woven scrim. 
     A suitable such material is available from Alhstrom Corporation as Grade 27500 Scrim. 
     With reference to FIG. 6, frame element  30  is placed in trench  15  of foam element  10 —the use of an adhesive to secure frame element  30  in place is not required. Trim cover  35   a  is inverted in a manner similar to that illustrated in FIG.  3  and lowered over foam element  10  in the direction of arrow B. Thereafter, trim cover  35   a  is applied to cover foam element  10  in the same manner as described above. Due to the selection of inner layer  70  to have the prescribed coefficient of friction with respect to the foam element set out above, it is possible to “unroll” trim cover  35   a  over foam element  10  without misaligning frame element  30  and without resulting in having a portion of foam element  10  protrude from the opening of trim cover  35   a.    
     Thereafter, a pair of bottom flaps  37  in trim cover  35   a  may be folded and sealed to complete production of the covered foam element. 
     Thus, the use of trim cover  35   a  allows for facilitating the production of a covered foam element having improved “fit and finish” or craftsmanship without the requirement of using additional materials such as adhesives and/or additional labour as described above with reference to FIGS. 1-4. Such improved craftsmanship may be manifested in one or more of: production of foam articles with reduced occurrence of visible wrinkling of the trim cover; the ability of use tighter fitting trim covers; the production of parts having the appearance of relatively straight seams; the production of parts where the seams are aligned in the finished product; and/or facilitation of finessing the product (if required) during post-covering operations. Other advantages will be apparent to those of skill in the art having the present specification in hand. 
     While this invention has been described with reference to illustrative embodiments and examples, the description is not intended to be construed in a limiting sense. Thus, various modifications of the illustrative embodiments, as well as other embodiments of the invention, will be apparent to persons skilled in the art upon reference to this description. It is therefore contemplated that the appended claims will cover any such modifications or embodiments. 
     All publications, patents and patent applications referred to herein are incorporated by reference in their entirety to the same extent as if each individual publication, patent or patent application was specifically and individually indicated to be incorporated by reference in its entirety. 
     APPENDIX 
     Coefficients of Friction of Soft Trim Material 
     GM9206P 
     1. SCOPE This procedure is used to determine the coefficients of friction of materials using ASTM D1894, Method A or B. 
     NOTE: If a strain gage is used to determine the friction, slightly higher results will be obtained because of the pulleys. 
     2. Equipment Required 
     2.1 Surface Friction Tester. Custom Scientific Instrument Model #CS-152S, 13 Wing Drive, Cedar Knolls, N.J. 07927. 
     2.1.1 Weight of sled, 300 g (foam coated) 
     2.1.2 Speed of moving plane, 300 mm/minute 
     2.2 Humidity cabinet 
     2.3 Clean, white, cheesecloth 
     2.4 Chlorothane, 9981224 
     2.5 Pressure sensitive tape, double backed 
     2.6 Polyethylene bag 
     2.7 Teflon cloth (NOTE: Teflon cloth was replaced with a sample of foam (i.e., equivalent to the foam element discussed above) having the following dimensions: 3×12×½) 
     3. Test Procedure 
     3.1 Before testing, condition all samples to be tested in the humidity cabinet at 21 C. and 50% RH for a period of 4 h. After conditioning, samples may be stored in the polyethylene bag for a maximum for a period of 1 h. 
     3.1.1 On the moving plane of the testing machine, place the sheet of teflon using the pressure sensitive tape. 
     3.1.2 Clean the surface of the teflon with the chlorothane and cheesecloth. Wipe the cleaned surface with a dry piece of cloth to make sure that no residue remains. 
     NOTE: This should be done 4 h prior to any testing, preferably at the end of each days usage to provide ample time to dry. 
     3.1.3 On the underside of the sled, on top of the foam, place a 64×64 mm piece of pressure sensitive tape. 
     3.1.4 Place a precut 64×100 mm sample, uncoated side, against the tape on the underside of the sled allowing the flap to be wrapped around the front edge of the sled and attached to the metal with a piece of tape. 
     3.1.5 Place the sled with the sample attached on the teflon cloth, coated side down, and start the machine. 
     3.1.6 Three tests will be conducted on the same piece of coated material and the average of the three tests will be the amount of friction found in grams 
     NOTE: Static readings will not be used and should be disregarded when averaging the results.