Abstract:
A headliner for the interior of the vehicle, such as an automobile, includes a porous polyurethane substrate having an A-side surface and a B-side surface. The B-side surface is united with reinforcing layer. The A-side surface is concealed with a decorative cloth, optionally having a foamed backing, exposed to the interior of the vehicle. Interposed between the A-side surface and the decorative cloth is a multilayered laminate, which includes an adhesive layer for adhering the multi-layered laminate to the decorative cloth, a barrier layer for preventing the polyurethane or polyurethane precursors from bleeding therethrough during formation of the substrate; and a shape-retaining layer having sufficient strength to prevent the pores in the A-side surface of the substrate from substantially influencing the outer appearance of the decorative cloth.

Description:
RELATED APPLICATIONS  
       [0001]    This is a conversion of Provisional Application No. 60/130,557 filed on Apr. 22, 1999 and Provisional Application No. 60/132,765 filed on May 6, 1999. The complete disclosure of Provisional Application No. 60/132,765 is incorporated herein by reference. 
     
    
     
       BACKGROUND OF THE INVENTION  
         [0002]    1. Field of the Invention  
           [0003]    This invention relates to headliner components for vehicles, and in particular to headliner components comprising an impregnated polyurethane substrate and at least one multi-layered laminate for uniting the substrate to a decorative material. This invention further relates to a method of making the headliner components.  
           [0004]    2. Description of the Related Art  
           [0005]    Headliners are commonly installed in vehicles to provide a decorative appearance to the ceilings of vehicle interior compartments. An example of a known headliner construction is shown in FIG. 2 and generally designated by reference numeral  200 .  
           [0006]    As shown in FIG. 2, the headliner  200  includes a relatively thick rigid substrate  202 , which can be a fiberglass-impregnated polymer-based material, such as a fiberglass-impregnated polyurethane. The surface of the substrate  202  facing towards the vehicle interior compartment (not shown) is known in the industry as the “A-side”. In the illustrated embodiment, the A-side has a barrier layer  204  contacting the A-side surface of the substrate  202 . The barrier layer  204  is commonly made of a polyethylene film. The barrier layer  204  is interposed between the substrate  202  and a decorative cloth material  206  having a foamed backing  208 . The decorative cloth material  206  is exposed to the vehicle interior compartment and conceals the substrate  202  and the barrier layer  204  from view.  
           [0007]    Positioned on the opposite side of the substrate  202 , also known in the industry as the “B-side” of the substrate  202 , is another barrier layer  210 , which can be made of a similar material to the barrier layer  204 . A vibration-dampening layer (also known as an anti-squeak layer)  212  is optionally interposed between the barrier layer  210  and the vehicle frame (not shown) to minimize rattles and squeaks caused by relative movement between the headliner  200  and the vehicle frame during operation of the vehicle. The vibration-dampening layer  212  is commonly made of a foamed polymeric material.  
           [0008]    It is known to produce the headliner  200  by placing the barrier layers  204  and  210  on opposite facing mold dies, respectively, then placing layers of fiberglass on the barrier layers  204  and  210  so that the layers of fiberglass face each other to define a mold cavity therebetween. Next, polyurethane precursors, such as polyols and polyisocyanates, are mixed and sprayed into the mold and the polyurethane is formed by compression molding, causing the fiberglass to disperse in the polyurethane substrate  202 . The fiberglass-impregnated substrate  202  with united barrier layers  204  and  210  are then removed from the mold, trimmed, and united with the decorative cloth material  206  with foamed backing  208  on the A-side and the vibration-dampening layer  212  on the B-side.  
           [0009]    The above-discussed conventional headliner manufacturing process poses problems that significantly affect its profitability and productivity. In particular, polyurethane-forming reactions between polyisocyanates and polyols by their very nature tend to generate a substrate having pores or voids at the substrate surfaces, including the A-surface. The pores are primarily generated during the reaction between the polyol, catalyst, water, and isocyanate. The pores may be generated during initial forming of the headliner, and/or can become visible after the substrate  202  cools. Cooling can take 24 to 48 hours due to the relatively large thickness of the substrate  202 , which may be on the order of 4 mm to 28 mm.  
           [0010]    Although the substrate  202  is hidden from the interior compartment by the molded barrier layer  204  and the decorative cloth material  206 , the molded barrier layer  204  and the decorative cloth material  206  tend to conform to the contour of the A-surface of the substrate  202 . As a consequence, pores in the substrate  202  can cause unwanted dimples or pits to form in the decorative cloth material  206 . These pits or dimples are visible with respect to the vehicle interior compartment and, therefore, warrant additional processing steps to make the headliner visually acceptable.  
           [0011]    To address the problem of unwanted dimples and pits in the decorative cloth material  206 , it is common to shelf the substrate  202  for at least 24 to 72 hours after molding is completed to permit the substrate  202  to cool sufficiently to permit voids to appear in the A-surface. After this shelf period, either the voids are covered via a patching procedure (using, for example, polypropylene mesh tape) or, if the voids are too abundant, the substrate is scrapped.  
           [0012]    However, the shelving, inspection, and patching of substrates  202  is time-consuming and labor intensive and requires substantial storage space. Further, the 24-hour to 32-hour shelving of substrates  202  is sometimes insufficient to allow for void detection on the substrate surface. In particular, the relatively large thickness of the urethane substrate  202  compounds the problem of detecting voids in the A-surface of the substrate  202 , since sometimes the voids do not appear for several days or weeks. In instances in which the headliner has already been shipped to a purchaser and/or installed on a vehicle before the dimples and pits appear, the recalling of parts and disassembling of vehicle interiors to remove defective headliners can result, thereby upsetting the manufacturer and increasing expenses. Further, post-assembly inspection of the headliner  202  further increases labor costs.  
           [0013]    Thus, there is a significant need in the art for a vehicle headliner that eliminates or at least significantly reduces the formation of dimples and pits and the problems associated with detection of dimples and pits in the headliner. The process should desirably be capable of being implemented without requiring significant modifications to existing processes and manufacturing equipment.  
         SUMMARY OF THE INVENTION  
         [0014]    It is, therefore, an object of this invention to solve the aforementioned problems associated with the related art as well as to address the need expressed above. In accordance with the principles of this invention, this and other objects are attained by providing a headliner in which the reinforcing layer interposed between the A-side surface of the substrate and decorative cloth material comprises a multi-layered laminate. The multi-layered laminate includes, at least, an adhesive layer for adhering the multi-layered laminate to the decorative cloth, a barrier layer, and a shape-retaining layer. The barrier layer is constructed and arranged to prevent the polyurethane or polyurethane precursors from bleeding therethrough during molding of the polyurethane. The shape-retaining layer has sufficient strength to substantially prevent the pores in the substrate from influencing the outer appearance of the decorative cloth material.  
           [0015]    Also provided herein is a process of making a headliner that overcomes the above-discussed problems and attains the above-identified need in the art. Desirably, the practice the inventive process requires no or only minor modifications to conventional process equipment; thus, little capital expenditure is needed to convert to the inventive process.  
           [0016]    The principles of this invention enunciated above are applicable to various types of vehicles, including passenger cars, trucks, vans, utility vehicles, and others.  
           [0017]    These and other objects, features, and advantages of this invention will become apparent from the following detailed description when taken in conjunction with the accompanying drawings which illustrate, by way of example, the principles of this invention. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0018]    The accompanying drawings facilitate an understanding of this invention by depicting an embodiment of the invention and comparing it to a known headliner. In such drawings:  
         [0019]    [0019]FIG. 1 is a sectional view of a headliner in accordance with an embodiment of this invention;  
         [0020]    [0020]FIG. 2 is a sectional view of a known headliner; and  
         [0021]    [0021]FIG. 3 is a schematic view showing an example of the placement of a headliner in a vehicle.  
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0022]    Referring now more particularly to the drawings, a headliner of an embodiment of this invention is shown in FIG. 1 and generally designated by reference numeral  100 . The headliner  100  includes a relatively thick rigid substrate  102 , which can be a fiberglass-impregnated polymer-based material, such as a fiberglass-impregnated polyurethane. The surface of the substrate  102  facing towards the vehicle interior compartment (not shown) is known in the industry as the A-side surface, whereas the opposite surface of the substrate  102  facing away from the vehicle interior when the headliner  100  is mounted is known as the B-side surface. Generally, the thickness of the impregnated substrate  102  is, for example, in a range of from about 4 mm to about 24 mm, and more preferably is from 4 mm to 18 mm. Representative densities for the impregnated substrate  102  range from 48 kg/m 3  to 160 kg/m 3  (3.0 to 10.0 lbs/ft 3 ).  
         [0023]    Positioned on the A-side surface of the substrate  102  is a multi-layered laminate  120 , which in the illustrated embodiment is a tri-layered laminate. The multi-layered laminate  120  is interposed between the substrate  102  and a decorative cloth material  106  having an optional foamed backing  108 . The decorative cloth material  106 , which can be made of, by way of example, nylon, rayon, polyester, cotton, or combinations thereof, is exposed to the vehicle interior compartment and conceals the substrate  102  and laminate  120  from view. The thickness of the tri-layered laminate  120  can be in a range of from 0.025 mm to 0.051 mm (i.e., 1.0 mils to 2.0 mils, or 0.0010 inches to 0.0020 inches), preferably 0.038 mm to 0.051 mm (i.e., 1.5 mils to 2 mils, or 0.0015 inches to 0.0020 inches) .  
         [0024]    The first layer of the tri-layered laminate  120  is an adhesive layer  122 , which adheres the multi-layered laminate  120  to the decorative cloth  106  and its optional foamed backing  108 . In a preferred embodiment, the adhesive layer  122  is ethylene-vinyl acetate, although other less preferred adhesives, such as polyethylene, may be used. Generally, the deposition of the adhesive layer  122  is controlled to produce a thickness which, when measured as concentration over a cross section of the adhesive layer  122 , is in a range of from 30 g/m 2  to 40 g/m 2 . The ethylene-vinyl acetate layer  122  is preferably corona treated, e.g., flame treated or electrically or electrostatically charged, to have a dyne level from 46 to 55, preferably from 47 to 49 dynes. The adhesive layer  122  should have a softening temperature lower than the temperature at which the decorative cloth material  106  thermally degrades, so that the adhesive layer  122  can be softened or melted without discoloring the decorative cloth material  106 . Generally, softening temperatures of from about 99° C. (210° F.) to about 104° C. (220° F.) are preferred for the adhesive layer  122 .  
         [0025]    The second layer of the laminate  120  is a barrier layer  124  that functions to prevent the polyurethane and polyurethane precursors from bleeding through the laminate  120  during the molding process, such as compression molding, in which the laminate  120  is placed in a mold die prior to injection of polyurethane precursors for forming the substrate  102 . The barrier layer  124  is preferably a film comprising polyethylene, preferably with pores not greater than 25 microns. Other materials, such as polypropylene, polyethylene-polypropylene copolymer films, and other olefin polymers, copolymers, and terpolymers can be used, so long as the materials can provide the desired barrier function at a suitable thickness while exhibiting acceptable molding, fluidity and softening point. Generally, the deposition of the barrier layer  124  is controlled to produce a thickness which, when measured as concentration over a cross section of the barrier layer  124 , is in a range of from 10 g/m 2  to 20 g/m 2 , preferably 16 g/m 2 . The elongation of the barrier layer  124  is preferably at least 40%.  
         [0026]    The third layer of the laminate  120  is a shape-retaining layer  126  having sufficient strength to prevent the configuration of the shape-retaining layer  126  from being influenced by pores in the substrate  102 . The shape-retaining layer  126  thereby prevents the decorative cloth material  106  from conforming to pores in the A-side surface of the substrate  102  so that the decorative cloth material  106  is free of pits and dimples. Generally, the deposition of the shape-retaining layer  126  is controlled to produce a thickness which, when measured as a concentration over a cross section of the shape-retaining layer  126 , is in a range of from 30 g/m 2  to 40 g/m 2 . The shape-retaining layer  126  preferably comprises a spun bond (or “non-woven”) polypropylene or polyester. As referred to herein, spun bond or non-woven materials are characterized by an absence in distinction of directional properties. As with the barrier layer  124 , the shape-retaining layer  126  preferably has an elongation of at least 40%. Antioxidants can be added to the barrier and shape-retaining layers  124  and  126 .  
         [0027]    The shape-retaining layer  126  of the laminate  120 , which is preferably disposed closest to the substrate  102 , is primarily responsible for imparting the laminate  120  with most of its physical properties, although the barrier layer  124  has sufficient influence as to cause distinctions in directional properties of the laminate  120 . Desirably, the laminate  120  has a machine tensile strength and cross-machine tensile strength (ASTM D 882-83) in ranges of 2700-2900 psi and 2400-2600 psi, respectively, and more preferably 2800 psi and 2500 psi, respectively. The elongation (ASTM D 882-89) of the laminate  120  is preferably 40-60%, with the machine elongation preferably being 45% and the cross-machine preferably being 56%. The tear strength (ASTM D 1922-67) is preferably 512±50 grams/16 plies along the machine direction and 316±50 grams/16 plies along the cross-machine direction.  
         [0028]    It should be understood that additional layers, including more than one of the layers  122 ,  124 , and  126 , can be included in the multi-layered laminate  120 , so long as the additional layers do not interfere with the above-discussed functions of the layers  122 ,  124 , and  126 .  
         [0029]    In accordance with a preferred embodiment, the laminate  120  can be prepared as follows. The non-woven shape-retaining layer  126  is extruded at approximately 0.13 mm to 0.15 mm (5 to 6 mils, or 0.005 inch to 0.006 inch) thickness onto the barrier layer  124 . The layers  124  and  126  are then run through a nip roller to achieve a desired film thickness of approximately 0.025 mm to 0.051 mm (i.e., 1.0 mils to 2.0 mils, or 0.0010 inches to 0.0020 inches), thus forming a bi-laminate. The layers  124  and  126  are then passed through a series of chiller rollers, followed by a series of heater elements to warm the bi-laminate. After the bi-laminate is formed, the adhesive layer  122  is fed onto the bi-laminate of layers  124  and  126  then passed with layers  124  and  126  through a series of hot rollers which compress and laminate the adhesive film  122  to layer  124  to make the tri-laminate  120 . The tri-laminate  120  is cooled and, optionally, cut and/or rolled for temporary storage.  
         [0030]    Positioned on the opposite side of the substrate  102 , also known in the industry as the “B-side” of the substrate  102 , is a barrier layer  110 . In a preferred embodiment, the barrier layer  110  is a Rochelle (polyethylene copolymer) film, which is available from Rochelle Plastics of Rochelle, Ill. and has a Tg of 83° C. It is also within the scope of this invention to use other materials as the barrier layer  110 , including the use of the above-described multi-layered laminate as the barrier layer  110 . A vibration-dampening layer  112  is optionally interposed between the barrier layer  110  and the vehicle frame (not shown) to minimize rattles and squeaks cause by relative movement between the headliner  100  and the vehicle frame. A representative vibration-dampening layer  112  is flame laminate polyether grade 11330XXX, available from General Foam of East Rutherford, N.J. As referred to herein, the vibration-dampening layer  112  also encompasses a scrim material, such as one having either (a) a bilaminate structure composed of a non-woven polypropylene film and a film of polypropylene, polyethylene, or polypropylene-polyethylene copolymer or (b) a trilaminate composed of two non-woven polypropylene films sandwiching a film of polypropylene, polyethylene, or polypropylene-polyethylene copolymer. The thickness of the non-woven polypropylene preferably is controlled to provide about 33.9 grams/m 2  (1 ounce/yard 2 ) of material, whereas the polyethylene and/or polypropylene is about 35.9 grams/m 2  (30 grams/yard 2 ).  
         [0031]    A process of making a headliner in accordance with an embodiment of this invention will now be described in detail.  
         [0032]    The substrate  102  is generated in a continuous manner by stacking onto a conveyor a Rochelle (polyethylene copolymer film, such as DOW 906, DOW 909, and Nolar films) barrier layer  110  and a fiberglass layer, and loading the stacked layers onto a first die of a compression molding apparatus. A suitable fiberglass roll is available from Nicofiber of Shawnee, Ohio, product number N754, and preferably has a thickness of 0.2 mm to 0.3 mm (i.e., 8-12 mils, or 0.008 inch to 0.012 inch). A separate conveyor delivers the multi-layered laminate  120  stacked with another fiberglass layer to a second die of the compression molding apparatus so that the fiberglass layers face each other and form a cavity therebetween. Next, polyurethane precursor materials, i.e., polyols and polyisocyanates, are sprayed into the mold and the polyurethane is compression molded. The spraying process may be performed via a standard X-Y pattern, with the spray head positioned 30.5 to 61 cm (12 to 24 inches) from the spraying surface. Representative polyols and isocyanates are RIMLINE 87335 and RUBINATE 8700, respectively, which are both available from ICI of Sterling Heights, Mich. For these particular materials, the ratio (in grams) of isocyanate to polyol is preferably about 0.541:1±0.050. Because of the rapid reactivity of the polyurethane precursors towards each other, the spraying step should be conducted quickly, preferably on the order of not more than 5 to 10 seconds, more preferably 5 to 6 seconds. The precursors can be introduced into the mold cavity at a chemical temperature of about 32° C.±5° C. (about 90° F.±10° F.). Alternative polyols and isocyanates are BASF ELASTOFLEX TF-23640R polyol and TF-23640T isocyanate, available from BASF of Wyandotte, Mich. For these alternative materials, the ratio (in grams) of isocyanate to polyol is preferably 0.537±0.040, and the temperature at which the precursors are introduced into the mold cavity is preferably about 26.7° C.±2.7° C. (80° F.±5° F.).  
         [0033]    In accordance with known molding techniques, one or both of the dies are moved towards each other to a closed position, in which the mold dies are slightly spaced apart from each other (e.g., via spacers) during compression molding to permit the urethane to foam to a desired thickness. During reaction of the polyurethane precursors and the foaming of the polyurethane, the fiberglass disperses in the polyurethane substrate from opposing die surfaces. The compression molding takes 1 to 2 minutes, preferably 60 to 80 seconds, although the molding time may depend on the thickness of the foam composite, i.e., its cross section The temperature of the upper and lower mold halves can be, for example, 74° C.±5° C. (about 165° F.±10° F.) and 63° C.±5° C. (about 145° F.±10° F.), respectively. During foaming, the polyurethane disperses in the fiberglass. Generally, the dispersion of fibers is not homogeneous throughout the polyurethane substrate  102 ; rather, higher concentrations of fiberglass are usually found at the opposite surfaces of the polyurethane substrate  102 .  
         [0034]    The molding time is directly dependent upon the amount of urethane applied during the spraying process and the cross-sectional thickness of the mold cavity to be filled. The composition and weight of the fiberglass also affects the cycle time and integrity of the finished product. The binder content is preferably in a range of 4.0 to 6.5% by weight, preferably 5.0% by weight, of the weight of the fiberglass. The fiberglass content is preferably in a range of from about 0.33 to 0.50 ounces per square foot.  
         [0035]    The fiberglass-impregnated substrate  102  with adhered multi-layered laminate  120  and reinforcement layer  110  are then removed from the mold, trimmed, and united with the decorative cloth material  106  with optional foamed backing  108  on the A-side and the vibration-dampening layer  112  on the B-side. The trimming of the excess material, known in the art as offal, can be performed by a water-jet process.  
         [0036]    The foregoing detailed description of the preferred embodiments of the invention has been provided for the purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise embodiments disclosed. Many modifications and variations will be apparent to practitioners skilled in this art. The embodiments were chosen and described in order to best explain the principles of the invention and its practical application, thereby enabling others skilled in the art to understand the invention for various embodiments and with various modifications as are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the following claims and their equivalents.