WO1993018218A1

WO1993018218A1 - A molded liner for a vehicle and method of making the same

Info

Publication number: WO1993018218A1
Application number: PCT/US1993/001908
Authority: WO
Inventors: Harry J. Wirz; Christel Brunnenkant; Don D. Halabisky; Richard H. Young, Sr.
Original assignee: Weyerhaeuser Company
Priority date: 1992-03-06
Filing date: 1993-03-04
Publication date: 1993-09-16
Also published as: CA2131462A1

Abstract

A method for making a molded liner for a vehicle, such as an automobile headliner, is provided. Discontinuous fibers such as natural wood pulp fibers, a substantial majority of which having a substantially continuous coating of a binder, which may be heat or solvent bondable, are delivered to a mold. These fibers are bound by the binder and are molded to selectively densify portions of the formed article. The fibers may be bound in a mat or they may be air laid into the mold. The fibers may be heated in the mold and/or prior to delivery to the mold. The liners may include an inner cover sheet or layer and an outer backing sheet or layer.

Description

A MOLDED LINER FOR A VEHICLE AND METHOD OF MAKING THE SAME

Cross Reference to Related Applications

This is a continuation-in-part application of U. S. Patent Application Serial Nos. 07/326,188, entitled "A Coated Fiber Product with Superabs^'orbent Particles"; 07/326,181, entitled "A Natural Fiber Product Coated with a Thermoset Binder Material"; 07/326,196 entitled "A Natural Fiber Product with a Thermoplastic Binder Material"; 07/673,685 entitled "Binder Coated Discontinuous Fibers with Adhered Paniculate Materials" filed on March 22, 1991; and 07/673,899 entitled "Binder Coated Discontinuous Fibers with Adhered Paniculate Materials" filed on March 22, 1991; all of which are incorporated by reference herein in their entireties.

BACKGROUND OF THE INVENTION This invention relates generally to a process for making a molded liner for a vehicle, such as a vehicle door, trunk, dash or headliner and to such molded articles comprised of fibers with a substantial majority of their surface area continuously coated with a binder material.

One prior art approach for producing products of a fibrous material and a binder is described in U. S. Patent No. 4,153,488 to Weigand; relating to a process for felting various fibers, including natural and synthetic fibers, with wood and paper fibers being specifically mentioned. The use of binders such as starch, synthetic resins and adhesives to strengthen the structure is mentioned. The fibers travel from a nozzle to a collecting screen for support with the variables affecting fiber travel being carefully controlled, including the distance from the nozzle to the collecting screen. The Weigand patent describes the introduction of an adhesive binder as a liquid spray prior to collecting the fibers on the screen. The binder is sprayed near the nozzle with the patent mentioning that the binder is able to adequately uniformly attach even to the fibers in the center of the stream without creating clots of plurality of fibers bound together by the binder. Various liquid binders are described, including starch solutions, liquid latex binders, and other liquid binders or suspensions in liquid such as resins. In connection with dry binders, the patent mentions mixing between four and 30 pounds of powder for each 100 pounds of fiber in a hammermill prior to directing the mixture from the fiber nozzle. The patent also recites that various additives in liquid or solid form may be incorporated into the mat, such as colorizers, fire retardants, seeds for grass, vegetables and the like. In liquid form, these may be included by spraying through the nozzle either in combination with the liquid binder, if any, or alone. In solid form, it is mentioned that these may be included into the product in the hammermill. As a specific example, grass seed is introduced in a desired quantity into the outlet of a cyclone collector with a starch binder being applied by nozzles to the product for binding purposes. A variety of products are disclosed in this patent including paper wipe products, particularly diapers, wiping cloths, and molded products including dash, hood, roof and trunk liners for automobiles. Fibers produced in accordance with the Weigand process have been observed to exhibit a poor coating of binder on the fibers. As a result, the present inventors have determined that molded products produced from such fibers lack strength, which is more pronounced in products of low density. Also, products from such fibers would lack desired levels of stiffness and moisture resistance.

U. S. Patent No. 4,486,501 to Holbek is another patent relating to the preparation of fibers coated with one or more polymers. Both thermoplastic and thermosetting polymers are mentioned. Fiber material and polymers are fed to a defiberator independently or the polymer or polymers are applied to the fiber material prior to feeding the mixture to the defiberator. The patent mentions that it is preferable to add the polymer or polymers to the fiber material in the form of a suspension of solid particles or in the form of a solution, or in a melted or heat- softened condition. Spraying the polymer onto a web of fibers is specifically mentioned. The fiber and polymers are exposed to impact or grinding forces in the defiberator wherein melting and softening of the polymer or polymers causes it to adhere to the defiberated fibers. Coated fibers may be cooled within the defiberator so as, according to this patent, to prevent them from sticking together. The use of polymers present at from five to thirty percent by weight of the fiber mass is mentioned and the patent mentions that the polymer and additives normally should not exceed fifty percent. Polymer additives are mentioned, including drying agents, hydrophobizing agents such as wax, fungicides, antioxidants, softeners, tensides, etc. The patent mentions that each single fiber processed in this manner is either completely covered by a film of the polymer, or partly covered by flattened droplet or film portions. Use of these fibers in making continuous web-shaped composite products of various types, including paper, pasteboard, cardboard, plates, non- woven textile materials, insulating materials, etc. are mentioned. The fibers are arranged in a layer having a suitable thickness and then bonded together, such as by exposing them to solvents and heat. Hot pressing treatments or other finishing treatments are mentioned and the use of higher pressures to produce more dense structures is also explained. Testing of fibers produced in accordance with the Holbek reference has confirmed that the bulk of the fibers are poorly coated with binder material. In addition, much of the binder ended up in clumps with fibers. Clumped fibers are more difficult to incorporate into finished products, for example, using air laying techniques. In addition, poorly coated fibers again lack the desired strength. U. S. Patent No. 5,057,166 to Young, Sr., et al. discloses a method of producing fibers which are substantially continuously coated with a binder material. A wide variety of thermoset and thermoplastic binders are mentioned as suitable for use in coating fibers. The use of thermoplastic binders which are heat- fused during processing of the fibers into products is mentioned. Densification of a web of fibers prior to or after delivery to a thermobonder is also mentioned. Use of the resulting material to manufacture products, such as absorbent pads, disposable diapers, webs, and the like, is mentioned, with or without blending of untreated fibers and with or without paniculate additives.

This Young, Sr. , et al. patent does not recognize the suitability of these fibers for use in molded products, any relationship between the degree of coating fibers, densification and strength of molded articles, or processing molded articles having areas of varying densities.

FIGS. 4 and 5 depict one prior art shaped liner 116 for the roof of a vehicle. The headliner 116 has a densified edge section 119 which adds rigidity and strength and a relatively undensified central section 117 which is intended to be sound absorbing. Various openings, some being shown in FIG. 5, may be provided for receiving fasteners and projecting vehicle components, such as overhead interior vehicle lights. The automobile liner may be densified around the openings in addition to along the vehicle periphery. Prior art automobile headliners resist sagging, the effects of heat and temperature, and absorb sound to varying degrees, depending upon the nature of the headliner.

From a sound absorbing and strength perspective, headliners of fiberglass have been preferred for many applications. A high percentage of all headliners being sold for automobiles are now made of fiberglass mats. FIG. 7 illustrates a section of a prior art headliner 116, taken along A-A of FIG. 5, of a fiberglass mat 200 with a hydroentangled nonwoven back overlay sheet 202. The mat 200 is typically formed of long glass fibers which are sprayed with phenolic resin and then heated to tack the material together. Latex material is sometimes applied to these fibers as a sizing. These mats with the cover sheet 202 are placed into a mold and shaped into the desired liner. A cloth overlay may be positioned at the vehicle interior side 204 of the FIG. 7 headliner. The vehicle exterior side 206 of the FIG. 7 headliner typically abuts the roof of the vehicle. Although headliners such as shown in FIG. 7 are sag, temperature and humidity resistant, and offer good sound absorbing properties from both the exterior and interior sides of the headliner, they suffer from significant drawbacks. For example, fiberglass liners tend to release fiberglass dust which is irritating to individuals exposed to the dust. Also, fiberglass is a much more expensive material on a per pound basis in comparison to other materials, such as wood pulp. Also, fiberglass headliners are relatively brittle, especially at the densified edge section, and often break as they are flexed or bent during the installation of the headliner. Broken headliners release additional fiberglass dust and are normally discarded as scrap. Other prior art automobile headlines have been made of corrugated paperboard. For example, as shown in FIG. 6, moving from the vehicle interior 204 to the vehicle exterior 206 sides of the headliner, one specific liner 116 of this type includes a core of corrugated medium 220 bounded at the interior by respective layers 222 of linerboard (e.g. 36 or 40 pound per 1000 square feet Kraft paper, which may be of double thickness at the edge of the liner for strength) 224 of a porous foam, and 226 of cloth. The corrugated medium 220 is bounded at the exterior by a polyolefin layer 228 and a liner board 230 (e.g. 36 or 40 pound per 1000 square feet Kraft paper). When placed in a mold and heated, the polyolefin layer melts and causes the liner to assume the shape of the mold when this layer resolidifies after reduction below the melt temperatures which are present in the mold. The exterior layer of material of this liner is relatively hard to reflect noise from the outside environment. However, interiorly, liners of this type are acoustically poor in comparison to fiberglass headliners. Therefore, although these liners are common, they are less desirable from a noise reduction standpoint than fiberglass liners.

Hardboard, pressed wood pulp liners have also been used. However, these liners are also acoustically very poor. Vehicle headliners having polyurethane and polystyrene foam cores have also been made. However, these headliners are believed more expensive and less sound absorbing than fiberglass headliners. Polystyrene foam headliners have been made by forming this material into a web, preheating the web, and vacuum/compression molding the preheated web into a cold mold wherein the material is shaped into the shape of the headliner.

Yet another prior art headliner is made of a resin containing polyester fiber core with resin saturated glass fiber surfaces. This material is much more costly than fiberglass core headliners and tends to have a high density rough surface, before being covered with cloth. Headliners of this material are believed to be less sound absorbing than those of fiberglass.

Therefore, a need exists for improved molded liners for vehicles produced from binder coated fibrous materials and improved processes for producing such products. SUMMARY OF THE INVENTION The present invention provides a method of making molded liners for vehicles. These liners are typically used for lining doors, trunks, hoods, dashes and roofs of vehicles. In the case of roof or headliners, it is important to provide a liner with sufficient strength to prevent sagging during use. Also, liners which are sufficiently ductile to prevent breakage during installation are also desirable. Also, it is desirable to minimize the migration of fibers (dust) from the liners during installation. Fibers, a substantial majority of which have a substantial majority of their surface area continuously coated with a binder material, are delivered to a mold. These fibers form at least one layer of the molded product together with any fibers (e.g. synthetic fibers) and additives blended therewith. The fibers are molded to selectively densify portions of the fibers. The fibers are bound together by the binder material in the shape of the liner. Although the liners may be of a uniform density, such as for use as vehicle trunk and hood liners, the liners, especially when used as vehicle headliners, are typically formed to have variable density areas, such as a first region of a first density and a second region of a second density.

The fibers may be air laid or wet laid into the mold and heated within the mold to the binder activating temperature. The binder material, being heat bondable, will bind the fibers together into the desired shape. The fibers may also be delivered to the mold in the form of a mat and similarly molded. The mat may be weakly bonded or "tacked" together prior to delivery to the mold, for example by heating the mat during its formation to cause the binder to stick the fibers together.

The fibers, whether delivered to the mold by air-laying or in mat form, may be heated prior to delivery to the mold. When the fibers are preheated, the mold may be at a temperature which is below the heat distortion temperature of the binder material.

The fibers may be delivered to the mold on a cover heet or cover overlay. The cover overlay sheet may be of a heat bondable material so that the fibers and the cover overlay may be heat bonded in the mold. The fibers and the cover overlay may be heat bonded prior to delivery to the mold. A backing sheet or backing overlay may also be included in a molded liner formed in accordance with the present invention. When a backing overlay is included, the fibers are positioned between the cover overlay and the backing overlay so that the fibers comprise a core therebetween. At least one of the cover and backing overlay sheets may be of a liquid permeable material. Alternatively, at least one of the cover and backing overlay sheets may be of a liquid impermeable material. For vehicle liners wherein noise is a problem, and therefore noise reduction is important, the cover and/or backing overlays may be of sound absorbing material, such as an open-celled or porous material. Also, in a preferred construction, the cover overlay, at the vehicle interior side of a vehicle headliner is sound absorbing so that sound can reach the core of the headliner. In addition, the backing overlay, at the exterior vehicle side of the headliner, is of a sound reflective material to reflect sound from the exterior of the vehicle away from the passenger compartment of the vehicle. The overlay sheets may each contain a resin or binder which when melted or cured adds rigidity to the overlay sheets.

The fibers used to make the molded liners are preferably discontinuous natural fibers, such as wood pulp fibers. The fibers may be arranged in plural layers within the liners. One or more of the plural layers of fibers may be dyed. To resist the effects of humidity, which can cause liners to sag, preferably at least eighty percent of all of the natural fibers included in the core of the liner have at least a substantial majority of their surface area coated with a binder material. Most preferably, virtually all of such natural fibers in the core are substantially continuously coated with the binder material. By virtually all of the fibers being substantially continuously coated, it is meant that over ninety-five percent of the fibers have at least ninety-five percent of their surface area coated with the binder material.

In a preferred method of the present invention, the liners have low density areas molded to a density ranging from 0.04 g/cc to 0.1 g/cc and high density areas ranging from 0.1 g/cc to 0.6 g/cc. Most preferably the liners have densities ranging from about 0.1 g/cc to about 0.3 g/cc with variable density areas being provided in the article.

Auto liners in accordance with the present invention are more ductile, and less prone to breakage than fiberglass headliners. As a specifically preferred embodiment, a core is provided of substantially continuously binder coated discontinuous wood pulp fibers. A sound passing layer, such as of an open structured nylon or polyester nonwoven material, is coated, impregnated or saturated with a heat fusible resin, with phenolic resin being a specific example, and positioned interiorly of the core. An interior cover layer, such as of adhesive, foam and cloth, is positioned interiorly of the sound passing layer. A resin (e.g. phenolic resin) impregnated, saturated or coated exterior cover layer, such as an open structured nonwoven material or a linerjDpard is positioned exteriorly of the core. This multilayered construction is heated in a mold, or heated prior to delivery to a cold mold, to bind the structure together in the form of the headliner. The resulting headliner is more ductile than fiberglass liners and yet absorbs sound like fiberglass liners. Surprisingly low density structures of wood pulp and having a high strength which are highly suitable for vehicle liners are

^• produced in this manner. The basic weight and density of these structures can be substantially like these properties in fiberglass liners. It is accordingly one object of the invention to provide improved vehicle liners.

Another object of the invention is to provide such articles which are strong, light weight, relatively rigid, and durable.

A further object of the present invention is to provide such articles which resist sagging, particularly under humid and high heat conditions, such as the interior of the passenger compartment or trunk of a vehicle.

Still another object of the present invention is to provide such articles of readily available and less costly raw materials, such as using discontinuous wood pulp fibers as a major component. Yet another object of the present invention is to provide liners with excellent sound absorption properties. The present invention relates to the above features, objects and advantages individually as well as collectively. These and other advantages, features and objects of the present invention will become more apparent from the description of the preferred embodiments hereinbelow.

BRIEF DESCRIPTION OF THE DRAWINGS In order that the present invention may be clearly understood and readily practiced, preferred embodiments will now be described by way of example only with reference to the accompanying figures wherein: FIG. 1 represents a schematic diagram of a preferred process used to manufacture the fibers used in manufacturing molded vehicle liners in accordance with the present invention;

FIG. 2 represents a schematic diagram of one process used for making a molded vehicle liner from such fibers in accordance with the present invention; FIG. 3 represents a schematic diagram of an alternative process used for making a molded vehicle liner in accordance with the present invention;

FIG. 4 represents a side view of one specific type of automobile headliner, of a prior art shape, formed in accordance with the present invention; FIG. 5 represents a top plan view of the molded liner of FIG. 4; FIG. 6 is a sectional view, taken along line A-A of the materials used in a prior art composite automobile headliner;

FIG. 7 is a sectional view, taken along line A-A of FIG. 5 of materials used in another prior art composite automobile liner;

FIG. 8 is a sectional view, taken along line A-A of FIG. 5, of one embodiment of the liner formed of materials in accordance with the present invention wherein the molded liner has a cover sheet and a backing sheet;

FIG. 9 a sectional view, taken along line B-B of FIG. 5, of an alternative embodiment of the molded vehicle liner formed of materials in accordance with the present invention wherein the liner has a core of plural fiber layers; FIG. 10 is a sectional view, taken along line A-A of FIG. 5, of an alternative embodiment of the molded vehicle liner formed of materials in accordance with the present invention;

FIGS. 11 and 12 are graphs showing the degree of coating of well coated and poorly coated fibers used in a comparative example; FIGS. 13 and 14 are graphs (on two different scales) of the tensile index versus densification of molded products produced from the well coated and poorly coated fibers.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT The present invention provides a method for making a molded vehicle liner. By way of example only, such articles may include automobile headliners. It will be appreciated that other three dimensional molded articles may be made using the process of the present invention.

The molded liners are comprised of fibers which are at least partially coated and more preferably virtually all of the natural fibers included in the product are substantially continuously coated with a binder material. The fibers are bound together by the binder material in the shape of the article. A wide variety of synthetic and/or natural fibers may be used in forming the article. However, it is preferable to use discontinuous natural fibers, such as wood pulp fibers either alone or in combination with from two to fifty percent, by weight, staple synthetic fibers. The term natural fibers refers to fibers which are naturally occurring, as opposed to synthetic fibers. Non-cellulosic natural fibers are included, with chopped silk fibers being one example. In addition, the term natural fibers includes cellulosic fibers such as wood pulp, bagasse, hemp, jute, rice, wheat, bamboo, corn, sisal, cotton, flax, kenaf, and the like and mixtures thereof. The term discontinuous fibers refers to fibers of a relatively short length in comparison to continuous fibers treated during an extrusion process used to produce such fibers. The term discontinuous fibers also includes fiber bundles. The term individual fibers refers to fibers that are comprised substantially of individual separated fibers with at most only a small amount of fiber bundles. Chopped or broken synthetic fibers also fall into the category of discontinuous fibers. Although not limited to any particular type of fiber, the synthetic fibers commonly are of polyethylene, polypropylene, acrylic, polyester, rayon and nylon. Discontinuous fibers of inorganic and organic materials, including cellulosic fibers, are also included in the term discontinuous fibers.

For purposes of convenience, and not to be construed as a limitation, the following description proceeds with reference to the treatment of individual chemical wood pulp fibers. The treatment of individual fibers of other types and obtained by other methods, as well as the treatment of fiber bundles, can be accomplished in the same manner.

When relatively dry wood pulp fibers are being treated, that is fibers with less than about ten to twelve percent by weight moisture content, the lumen of such fibers is substantially collapsed. As a result, when binder materials, in particular latex binder materials, are applied to these relatively dry wood pulp fibers, penetration of the binder into the lumen is minimized. In comparison, relatively wet fibers tend to have open lumen through which binder materials can flow into the fiber in the event the fiber is immersed in the binder. Any binder that penetrates the lumen may contribute less to the desired characteristics of the treated fiber than the binder which is present on the surface of the fiber. Therefore, when relatively dry wood pulp fibers are treated, less binder material is required to obtain the same effect than in the case where the fibers are relatively wet and the binder penetrates the lumen.

Binders used to treat the fibers broadly include substances which can be applied in liquid form to entrained fibers during treatment. These binder materials are preferably of the type which are capable of subsequently binding the fibers produced by the process to one another or to other fibers during the manufacture of webs and other products using the treated fibers. Most preferably these binders comprise organic polymer materials which may be heat fused or heat cured at elevated temperatures to bond the fibers when the fibers are used in manufacturing products. Also, in applications where solid paniculate material is to be adhered to the fibers by the binder, the binder must be of a type which is suitable for this purpose. Suitable binders include polymeric materials in the form of aqueous emulsions or solutions and nonaqueous solutions. To prevent agglomeration of fibers during the treatment process, preferably the total liquid content of the treated fibers during treatment, including the moisture contributed by the binder together with the liquid content of the fibers (in the case of moisture containing fibers such as wood pulp), must be no more than about forty-five to fifty-five percent of the total weight, with a twenty-five to thirty-five percent moisture content being more typical. Assuming wood pulp is used as the fiber, the moisture contributed by the wood pulp can be higher, but is preferably less than about ten to twelve percent and more typically about six to eight percent. The remaining moisture or liquid is typically contributed by the binder. These polymer emulsions are typically referred to as "latexes." In the present application, the term "latex" refers very broadly to any aqueous emulsion of a polymeric material. The term "solution" means binders dissolved in water or other solvents, such as acetone or toluene. Polymeric materials used in binders in accordance with the present method can range from hard rigid types to those which are soft and rubbery. Moreover, these polymers may be either thermoplastic or thermosetting in nature. In the case of thermoplastic polymers, the polymers may be a material which remains permanently thermoplastic. Alternatively, such polymers may be of a type which is partially or fully cross- linkable, with or without an external catalyst, into a thermosetting type polymer. Specific examples of latexes are set forth in U. S. Patent No. 5,057,166 and include, but are not limited to: ethylene vinyl acetate, polyvinyl acetate, acrylic, polyvinyl acetate acrylate, styrene, and polyvinyl chloride. One specifically preferred binder material is DL2681/97780 available from Reichhold Chemical Corporation of Dover, Delaware, and applied to the fibers in an amount which is from about seven to fifty percent, and most preferably about thirty percent by weight to the total weight of the fibers and the binder.

Certain types of binders enhance the fire resistance of the treated fibers, and thereby of products made from these fibers. This is of particular benefit in products to be used in vehicles or other applications wherein fire retardancy is extremely important. For example, polyvinyl chloride, polyvinyl dichloride, ethylene vinyl chloride and phenolic binders are fire retardant.

Surfactants may also be included in the liquid binder as desired. Other materials, such as colorants or dyes, may also be mixed with the liquid binder to impart desired characteristics to the treated fibers. If a water insoluble dye is included in the binder, the dye remains with the fibers, rather than leaching into aqueous solutions used, for example, in wet laying applications of the treated fibers. Also, dye would not leach from liners made from these fibers when these products are exposed to moisture, for example to spilled beverages. Solid particulate materials, such as pigments, may also be mixed with the binder for simultaneous application with the binder. In this case, the particulate material is typically coated with the binder rather than having exposed uncoated surfaces when adhered to the fibers as explained below. Other liquid materials may also be mixed with the binder with the mixture still performing its function. In addition, in accordance with the invention, one or more solid particulate materials may be adhered to the fibers to provide desired functional characteristics. The solid particulate materials are typically applied to a binder wetted surface of the fibers and are then adhered to the fibers by the binder as the binder dries. In this case, heat curing or heat fusing of the binder is not required to adhere the particles to the fibers. Although not limited to specific materials, examples of suitable particulate materials include pigments, such as titanium dioxide and CaCO₃; fire retardant materials, such as alumina trihydrate and antimony oxide; and hydrophobic and oleophobic materials. Thus, the solid particulate materials are not limited to narrow categories. FIG. 1 shows an apparatus, which is suitable for providing the binder coated fibers used in the molded articles of this invention. In this apparatus, a sheet 10 of fibrous material, such as chemical wood pulp, is unrolled from a roll 12 and delivered to a refiberizing apparatus, such as a conventional hammermill 14. The sheet 10 is readily converted into individual fibers 16 within the hammermill. These individual fibers are delivered, as by a conveyor 18, to a fiber loading zone 20 of a fiber treatment apparatus. Loading zone 20 forms part of a fiber treatment conduit 22. The illustrated conduit 22 comprises a recirculating loop. A blower or fan 24 in the loop 22 is positioned adjacent to the fiber loading zone 20. Blower 24 is capable of moving a gaseous medium, such as air, at a velocity and volume sufficient to entrain the fibers which have been loaded into zone 20. The entrained fibers circulate in a direction indicated by arrow 26 through the loop and pass through the loading zone 20 and blower 24 each time the loop is traversed.

The entrained fibers traveling in the loop pass one or more binder material application zones, with one such zone being indicated in at 28. This binder material application zone 28 forms a part of the conduit 22. A mechanism is provided at the binder application zone for applying a liquid binder solution to the entrained fibers. Plural nozzles, in this case nozzles 30, 32 and 34, may be used to apply the liquid binder material. These nozzles produce an atomized spray or mist of binder drops which impact and coat the fibers as the fibers pass the nozzles. Plural valves, 36, 38 and 40 are operated to control the flow of liquid binder material to the respective nozzles 30, 32 and 34. In the illustrated configuration, a first liquid binder material from a tank or other source 42 is delivered to the three nozzles 30, 32 and 34 when valves 36 and 38 are opened and valve 40 is closed. As the fibers recirculate through the conduit 22, and each time they pass the nozzles, an additional amount of the first liquid binder material is applied. Different surfaces of the fibers are exposed to the nozzles 30, 32 and 34 as the fibers travel through the material application zone 28. After the desired amount of the first liquid binder material has been applied, valve 36 is closed. If desired for a particular application, a second liquid binder material from a tank or other source 44 may also be applied to the fibers. With valves 38 and 40 open and valve 36 closed, this second liquid binder material is applied to the fibers through each of the nozzles 30, 32 and 34. In addition, the two liquid binder materials may be simultaneously applied, at successive locations in zone 28. More than two types of liquid binder materials may be applied by adding additional binder sources and suitable valving and nozzles. At this point, a filler material such as Kaolin clay, Ti0₂, or ground calcium carbonate particles can be introduced to the system so that they attach to the coated fiber surface. As a result, when used in producing a molded product, the product will have a smoother, more uniform surface. The fibers may be retained in the loop until they have dried. The recirculation of the fibers may then be stopped and the fibers removed at the loading zone 20, which then functions as a fiber removal location. However, as shown in FIG. 1, a cyclone separator 46 is selectively connected by a conduit section 48 and a gate valve 50 to the conduit 22. At the same time a valve 52 is opened to allow air to enter the loop 22 to compensate for air exiting through the separator 46. With the separator in the loop, the entrained fibers are collected in the separator and then removed from the separator at a fiber removal outlet 54.

As a result, treated fibers are produced, a substantial majority of which have a substantial majority of their surface area continuously coated with a binder, with optional particles being adhered to the fibers by the binder. Most preferably, a substantial majority of the fibers, and more typically virtually all (in excess of ninety-five percent) of the fibers, have a substantially continuous coating of a binder material. At least a substantial majority (seventy percent) of the bulk treated fibers are unbonded so that they may be readily blended with other fibers and/or processed into products (such as by conventional air laying techniques). By using a heat curable material as the binder, the fibers may be subsequently heated to cure the binder and fuse them together. The fibers may also be combined with other nontreated fibers and molded into a vehicle liner as explained below.

The binder provides a coating over a substantial majority of the surface area, meaning at least about eighty percent of the surface area of the individual fibers. More typically, the fibers are substantially continuously coated with a continuous binder coating over substantially the entire surface (at least about ninety-five percent of the surface area) of the individual fibers. Also, in many cases virtually all of the surface area of the individual fibers is continuously coated, meaning that the surface coating is an unbroken and void free, or at the most has a few voids of less than the diameter of a fiber. Also, binder may be applied so that a substantial majority of the fibers, that is at least eighty percent of the fibers: (a) have a substantial majority of their surface area coated; (b) a substantially continuous coating; or (c) have virtually their entire surface continuously coated. The remaining fibers typically have varying degrees of coating ranging from discrete patches of coating to a major portion of their surface (fifty percent or more) being continuously coated. Variations occur due to the type of binder being applied, the loading of the binder, and the fact that not all of the fibers receive the complete treatment. Also, substantially all (at least about ninety to ninety-five percent) of the individual fibers and fiber bundles being treated in bulk have been produced with coatings falling into the above three categories. Of course, for many applications it is desirable that substantially all of the fibers of the bulk fibers being produced have a substantially continuous coating or virtually their entire surface continuously coated because, in this case, the characteristics of the binder (as opposed to exposed fiber surfaces) controls the properties of the fibers. For example, wood pulp fibers coated with a hydrophobic binder will not pick up moisture from the air, which could otherwise cause a liner of these fibers to sag. It has also been found that binder loading levels of approximately about seven percent of the combined weight of the binder and fiber results in fibers a substantial majority of which, and more typically substantially all of which, have a substantially continuous coating.

In addition, the continuous coating is extremely uniform over the coated surface of the fibers and fiber bundles. For instance, a fiber coated with twenty percent by weight binder to the combined weight of the binder and fibers of a binder such as polyethylene (Primacor), forms a coating which is about 0.5 microns thick, plus or minus about 0.25 micron. If the coating add-on were forty percent by weight of this binder to the weight of the binder and fibers, then the coating thickness would be about 1.0 micron, plus or minus 0.25 micron.

The fibers, prior to molding, may have substantial amounts of binder material, yet still comprise individualized substantially continuously coated fibers. It has been found that the binder material must be included in an amount of at least about seven percent of the combined dry weight of the binder material and fibers in order to produce a substantially continuous binder coating on the fibers. With a substantially continuous coating, little or no surface area of the fibers is exposed and the desired characteristics added to the fibers by the binder material are not nullified or significantly altered by uncoated areas of the fiber. With a binder level of at least about ten percent of the combined dry weight of the binder material and fibers, the coated fibers are capable of bonding relatively strongly to one another when heat fused. In addition, substantially unbonded individualized fibers with binder levels of thirty percent to fifty percent and higher, such as above ninety percent and with no maximum limit yet being determined, can be produced. Also, high binder levels are preferably used to maximize the bond strength and to adhere solid particulate materials to the fibers. For some particles, however, lower binder concentrations may be used to reduce the possibility of the binder coating the particles and interfering with the functionalities.

An optional means for heating the binder coated fibers may be included in conduit 22. For example, heated air may be blended with the air flowing through the conduit. Similarly, a heater 56 may be included in conduit 22 for heating the fibers. The dried fibers from outlet 54 of the cyclone separator 46 may be deposited onto a conveyer 58. These fibers may then be heated in a thermobonder 60 to form a preheated fiber mat 62. Fibers may also be used as the wet laid sheet or otherwise wet laid, for example directly into molding equipment.

The resulting fibers are thereby coated with a sufficient amount of binder material to form a substantially continuous coating of binder material on the fibers. Furthermore, substantially unbonded individualized fibers may be produced in this manner. By substantially individualized, it is meant that ninety-five percent or more of the fibers are unbonded. Also, a substantial majority of the individual fibers, meaning seventy percent or more, may also be produced. By depositing the fibers wet with binder onto a belt or other conveyer, the fibers tend to stick together somewhat as the binder dries. This increases the handleability of the fibers in web form when used, for example when delivered in web form to a mold. Also the fibers may be heated in web form to above the heat distortion temperatures of the binder (that is, the temperature at which the binder begins to flow and become tacky) to cause some adhesion of the fibers prior to molding. This also increases the handleability of the webs. If the binder is a thermoset binder, this preliminary heating is preferably at a temperature below that which causes the binder to set. An apparatus for making the articles is shown in FIG. 2. The mat 62 of binder coated fibers is deposited on conveyor 64 and processed through thermobonder 65 along with a cover sheet material 66 and backing sheet material 68. The fibers of mat 62 thus comprise a core between cover sheet 66 and backing sheet 68, best seen in FIGS. 5 and 6. The binder material on the fibers of mat 62 and the cover and backing sheets, 66 and 68, may each be of a heat bondable material. For example, the cover and backing layers may be of rayon, polyester, nylon, or polypropylene or blends. A specific preferred example of a liquid impermeable material for the cover and/or backing layer is polyethylene from Dow Chemical Corp. A specific preferred example of a liquid permeable material for the cover and/or backing layer is rayon/polyester. These materials may be varied for production applications.

Following heating in thermobonder 65, the fibers will bind together and the cover sheet 66 and backing sheet 68 will be heat bonded to the core fibers. Alternatively, the cover and backing sheets may be adhesively secured to the core with or without thermobonding. A suitable adhesive is Zero Pack from

H. B. Fuller which, for example, could be sprayed onto the surface of the core prior to positioning the cover and backing layers.

At least one of the cover sheet 66 and backing sheet 68 may be of a liquid permeable or of a liquid impermeable material. Suitable liquid permeable materials include, but are not limited to, nylon, polyester, rayon polypropylene and blends thereof. Additional examples of suitable liquid impermeable materials include films of polyethylene, polypropylene and polyester and blends thereof along with nylon and polyvinyl chloride films.

In FIG. 2, the mat 62, cover sheet 66 and backing sheet 68 are heated in thermobonder 65 prior to delivery to mold 69. Mold 69 may then be at a temperature below the heat distortion temperature of the binder material. Again, the heat distortion temperature is the temperature at which the binder material will soften. It will be appreciated that the binder material must be heated to at or above the heat distortion temperature to bind the fibers together. This temperature is reached in thermobonder 65 (or in thermobonder 60). When reached in thermobonder 65, the fibers and cover and backing sheets are already bonded prior to delivery to mold 69. Therefore, mold 69 need not be heated to the heat distortion temperature to accomplish binding. Mold 69 is therefore not required to soften the binder material. A mold which is at a temperature below the heat distortion temperature is sometimes referred to herein as a "cold" mold. The temperature difference between the heated fibers and the cold mold causes a shock or quenching of the fibers after they have been formed into the desired shape established by the mold. The cold shock from the temperature differential causes the fibers to harden more quickly in the mold.

It will be appreciated that the fibers and cover and backing sheets need not be heated prior to delivery to the mold. The mold may be heated to at or above the heat distortion temperature to bind the fibers and cover and backing sheets. This temperature is preferably below the temperature at which charring of the fibers would occur.

A specific example, assuming the cover layer is rayon, the backing layer is polypropylene, and the binder is Synthemul™ 40-800 (from Reichhold Chemical Company) at least partially coated onto wood pulp fibers, the thermobonder 66 heats the combined core cover and backing layers to about 120- 130°C. While still above about 100°C, this heated material is delivered to a mold at 25-30 °C. The mold is typically closed for 0.5-2 minutes with a pressure of from about 100 to about 1000 psi being applied to the materials.

The mold 69 may be of any type suitable for producing an article having a first region of a first density and a second region of a second density. Molded vehicle liners of the invention and other articles frequently contain areas of variable density. As a result, the articles have variable strength and absorption characteristics within the article as will be described hereinbelow. In a preferred embodiment, the article is molded to a density of from about 0.04 g/cc to about 0.6 g/cc with areas of varying densities within the article. These densities are like those found in commercial fiberglass headliners.

The molded liner is removed from the mold onto conveyor 70. The sheets containing the molded articles would pass typically through a cutting device 72 such as a die or water knife. The molded articles may thus be formed in a continuous sheet. Cutting device 72 cuts each individual molded article out from the process sheet.

An alternative process in accordance with the present invention is shown in FIG. 3. In this case, fibers substantially continuously coated with binder material are delivered to a conventional air laying device 74 (such as a Danweb Model P75 Airlayer from Danweb Company of Denmark directly from the cyclone separator 46 shown in FIG. 1 via the line 54. These treated fibers may also be bagged or otherwise collected from the apparatus and then subsequently used in the production of the molded liners. Treated fibers may be mixed with untreated fibers 76 and/or staple fibers 78 (shown in bags in this figure) which are broken apart using a hammermill or other conventional means (not shown). Untreated fibers are fibers which are not coated or only partially coated with binder material. Staple fibers are fibers which are of a longer length than the treated fibers, such as rayon fibers, polyester, nylon, and polypropylene. Staple fibers and/or untreated fibers may be added to the treated fibers to strengthen and reinforce the molded product. Typically, staple fibers of from two to fifty percent by weight are added to the core of treated fibers.

The fibers may be mixed together in air laying device 74 and delivered in a mixture to the mold 76. This mixture may be heated prior to delivery to the mold, as by a thermobonder 66 described above, and/or heated in the mold to activate the binder. Alternatively, each type of fiber may be delivered separately to the mold, forming a molded article or core thereof comprised of plural layers of different types of fibers. A molded liner 116 with a core comprised of plural layers of fibers is shown in FIG. 9. For example, the top layer 62' of the core may comprise one hundred percent substantially continuously coated fibers, and the lower layer 62 may comprise a fifty/fifty mix of substantially continuously coated fibers and staple fibers. Other layers may also be included. Again, without limiting the myriad of options, another specific example is to provide a plural layer variable binder concentration containing molded product. For example, the top twenty percent of the fibers in the product may be substantially continuously coated fibers with a binder concentration of fifty percent by weight to the combined weight of the binder and fiber. In addition, the bottom eighty percent of the fibers may comprise a blend of twenty-five percent substantially continuously coated fibers, coated with binder in the amount of about twenty to about twenty-five percent of binder to weight of binder and fibers and seventy-five percent untreated or staple fibers. When molded under high pressure (2,000 psi), the top layer in this product forms a liquid impermeable surface and the bottom layer includes enough binder to provide stiffness to the molded product. Also, the heavier binder concentration in the top layer would serve to bind the core to an overlying cover sheet.

A cover or overlay sheet 80 may be delivered to the air laying device 74. As described above, this cover sheet may be of a liquid permeable or a liquid impermeable material. Although not shown in FIG. 3, the molded product may also include a backing sheet as previously described (e.g. delivered to the mold with the fibers sandwiched between the cover and backing layers). These overlay sheets may include a resin or other binder to rigidify the overlay sheets. For example, curable resins or binders which melt when heated may be used. The fibers are delivered to the mold 76 on cover sheet 80. Unless the fibers are preheated, the mold 76 is heated to the heat distortion temperature of the heat bondable binder material. The fibers are heated within mold 76, binding the fibers together. Cover sheet 80 may be heat bondable and in this case, is bound to the fibers in heated mold 76. Mold 76 is configured to provide a molded article of the desired shape and density.

It will be appreciated by those of ordinary skill in the art that air laid fibers may be heated prior to delivery to the mold by, for example, passing the fibers through a hot air stream. Preheating will cause the fibers to bind together prior to delivery to the mold. The mold may then be at temperature which is less than the heat distortion temperature of the binder to provide a cold mold as previously described. One specific example of a molded vehicle liner formed in accordance with the present invention is an automobile headliner 116 of the type shown in FIGS. 4 and 5. The headliner is formed by molding binder coated fibers, preferably wood pulp fibers into a desired shape. The headliner preferably consists entirely of, or of at least one layer of, fibers a substantial majority of which have a substantial majority of their surface area continuously coated with a binder. However, such fibers may be blended with untreated or only partially treated fibers. Most preferably, virtually all of the natural fibers included in the liner are substantially continuously coated with a binder material. The headliner preferably includes a nonwoven or fabric cover sheet. Both the fibers and the cover sheet may be dyed to a desired color. It is preferable to use plural layers of fibers, at least one of which is dyed. Synthetic fibers may be added to the natural fibers as reinforcing fibers. Headliners of this type are preferably provided with areas of differing densities. For example, for cushioning purposes, the central portion 117 of the headliner may be of a density of from about .04 g/cc to about .1 g/cc, and most preferably about .06 g/cc. For added strength, the side portions 119 of the headliner may be of a higher density, such as from about .15 g/cc to about .6 g/cc, and most preferably about .3 g/cc. Also, areas bordering openings in the headliner may also be densified, for example, to the same degree as the side portions, to add strength. Sag, due to gravity, is a factor that must be resisted in a vehicle headliner application. In this case, preferably an overlay is provided at each of the two major surfaces of the core, the core being formed of fibers as explained above.

The overlay at the interior (vehicle) side of the headliner 130 (FIG. 10) most preferably allows sound to pass through it and into the sound absorbing core 62. Preferably, the material does not increase the sound energy which is reflected from the undersurface of the headliner. That is, the material must not significantly change the flow resistivity of the structure. A nonwoven synthetic material or scrim with an open or porous structure, such as a spunbonded material, containing an applied rigidifying resin, is a specifically preferred material for the interior overlay. The resin may be sprayed, dipped, or otherwise applied to the interior overlay. A phenolic resin is a preferred example. A phenolic saturated polyester nonwoven is a specifically preferred example, with a Dynofiber™ web being one such material. This material is of a 29 gm per square meter polyester nonwoven (Remay™) saturated with 29 gm resin per square meter and is available from Dyno Overlays, Inc. of Tacoma, Washington. Polyester nonwovens are preferred because they are more ductile than glass fibers. Other resins, resin loadings, and resin systems may be used, such as two layer structure having a scrim or nonwoven as one layer and another layer which melts and bonds at the mold temperatures during formation of the liner. Again, the interior overlay for a headliner must have the desired sound penetration characteristics, when sound reduction is important in an application, as otherwise the structure will not have the desired sound absorbing properties characterized by fiberglass headliners. For example, resin impregnated 32 and 40 lb. per 1000 square feet Kraft paper is too sound reflective for the interior overlay when sound reduction is important.

The exterior overlay 132 (FIG. 10) at the exterior or roof side of the headliner may be of the same material as the interior overlay, such as a phenolic resin saturated polyester nonwoven sheet as described above. However, any resin coated or saturated material may be used, such as a resin coated or saturated Kraft liner because sound penetration is not as important at this location. That is, a sound reflective surface at the exterior overlay is often beneficial as the exterior overlay then assists in reflecting exterior road noise away from the interior of the vehicle. As also shown in FIG. 10, the interior surface of the interior overlay 130 may be covered with a conventional cover stock, such as a multilayered Guilford cloth, as described below.

As a more specific example, NB316 Southern Pine pulp from Weyerhaeuser company was coated with DL 2860 Styrene Butadiene Acrylonitrile from Reichold Chemical Company to provide fibers with binder at a level of binder which is thirty percent solids to the total weight of the binder solids and fibers. Although not specifically tested in this example, based upon our experience in fiber treatment, over ninety percent of these fibers would be substantially continuously coated. The fibers were then felted on an air laying system and thermobonded below the crosslinking temperature of the binder to soften the binder and tack the fibers together to aid subsequent handling and processing. Specifically, the fibers were placed in a through air thermobonder at 120°C for thirty seconds and the resulting web had a basis weight of about 800 grams per square meter and was densified by pressing to from 0.02 g/cc to 0.06 g/cc. This web constituted a core for a vehicle headliner.

Calendar rolls may be used for this pressing operation. The thermobonded mat was then heated and compressed in a mold at 177°C for two minutes to achieve crosslinking of the binder and the desired densification of the mat. The pressed panel was then removed from the press. The pressed panel had areas of differing density. The low density areas ranged from 0.04 g/cc to 0.1 g/cc and the high density areas ranged from 0.1 g/cc to 0.6 g/cc. The densities could be made higher or lower, if desired. For example, densities of up to about 1.2 g/cc or higher may be achieved. The core panel was overlayed (sandwiched between) by cover and backing overlay sheets of resin saturated polyester nonwoven (Dynofiber™) prior to the pressing operation. A cover sheet was then positioned on the interior side of the overlayed core and the assembled panel was then repressed at a temperature of 177°C for thirty seconds, causing a layer of the overlaying sheets to melt and bond to the core panel. A specifically preferred covering material is Guilford cloth, a tri-layered sheet material from Guilford Mills, Inc. of Greensboro, North Carolina. Guilford cloth has a cloth face, a thin foam intermediate layer and an adhesive back which adheres to the interior overlay during this repressing step. A two-step process is used in this case because the cover sheet would degrade if subjected to the temperature for the time required to cure the resin in the overlay sheets. Other resins and cover materials could be simultaneously pressed in a single step.

Again, for better acoustic suppression properties, one or both of the overlay sheets, the interior overlay sheets, is made of a material which allows sound to readily pass to the core.

To compare the ductility of headliners of the present invention and fiberglass headliners, two specific headliner structures, Structure "A" and Structure "B" were compared. Structure "A" was the core structure described above with the above described exterior and interior overlays of phenolic saturated polyester nonwoven material. Structure "B" was a commercially available fiberglass headliner (with its cloth cover removed) formed of a resin impregnated fiberglass mat and an interior overlay of a hydroentangled nonwoven material. For samples of Structure "A" and Structure "B" at the same density, tests (pursuant to ASTM D-1037) have confirmed that Structure "A" is significantly more ductile than Structure "B". The difference would be even more pronounced if the overlay sheets of Structure "A" are eliminated. The densities of Structures "A" and "B" that were tested ranged from about 0.12 gm/cm³ to about 0.15 gm/cm³. Comparisons were made between samples of the two structures at the same density.

It is expected that at higher densities, such as at the edge of a headliner, the differences in ductility between Structures "A" and "B" would be even more pronounced. That is, Structure "A" is more ductile than Structure "B" as evidenced by Structure "A" following a stress/strain curve that would have a higher energy to failure as defined by the area under the stress/strain curve than the case for Structure "B".

When the stress/strain curves were compared, Structure "A" was uniformly more ductile than Structure "B" for each of the tests conducted to date. As another specific comparative example, fibers were produced utilizing thirty percent by weight of latex solids (styrene-butadiene latex, 97-915 available from Reichhold Chemical Company, of Research Triangle, North Carolina) to NB 316 wood pulp available from Weyerhaeuser Company to produce well-coated fibers. Examples of these fibers were tested and confirmed that eighty percent of the fibers had at least ninety percent of their surface area continuously coated with the latex binder material. More specifically, these tests also indicated that about eighty- seven percent of the fibers had at least eighty percent of their surface area substantially continuously coated with binder.

In addition, poorly coated fibers were produced by adding thirty percent by weight, 97-910 latex solids to NB316 fluff pulp in a manner that limited the surface area of the fibers that were coated. Only about ten percent of the fibers had about eighty percent of their surface area continuously coated with binder. In addition, eighty percent of the fibers tested had from virtually no binder present to about forty-five percent of their surface area substantially continuously coated with binder.

Air laid pads, six inches in diameter, were formed in the laboratory of each of these materials. These air laid pads were through-air thermobonded at 120°C. for one minute. These pads were then pressed at 170°C. for two minutes to a variety of densities, ranging from 0.08 g/cc to 0.98 g/cc. The resulting densified and bonded structures were then tested for tensile index strengths in accordance with ASTM D648. The results are set forth in Table I, below.

TABLE I

Tensile Index vs Density of Well Coated and Poorly Coated 30% Latex on Pulp Fibers

Tensile Index Nm/g 50.48

18.92 9.75 1.88

15.03

2.23 1.22

0.20

As confirmed by this table, the use of fibers in vehicle liner products, a substantial majority of which are substantially continuously coated with binder, results in much stronger molded products. FIGS. 11-14 graphically illustrate these test results and set forth the best fit curve for these data points for molded products produced from the well coated and poorly coated fibers. Surprisingly, the use of well coated fibers allows the production of an extremely strong molded product, even at low densities. While the present invention has been described in connection with preferred embodiments, it will be understood that modifications and variations apparent to those of ordinary skill in the art are within the scope of the present invention.

Claims

WE CLAIM:

1. A molded automobile liner having at least one layer comprising discontinuous natural fibers, a substantial majority of the natural fibers in the layer consisting of substantially continuously binder coated natural fibers which are bound together by the binder material, the article having a density of from about 0.04 g/cc to about 1.2 g/cc.

2. A molded article according to claim 1 having first and second overlay sheets with the fibers comprising a core between the overlay sheets.

3. A molded article according to claim 2 in which at least one of the overlay sheets is of an open cell sound absorbing material.

4. A molded article according to claim 2 in which the overlay sheets each include a binder material.

5. A molded article according to claim 3 in which at least one of the overlay sheets is a nonwoven polyester material with cured phenolic resin.

6. A molded article according to claim 2 in which at least one of the overlay sheets is of a material which does not increase the sound reflectivity of the structure.

7. A molded article according to claim 6 in which said one of the overlay sheets is located at the interior side of a vehicle roof liner, and one of the overlay sheets being covering with a cover sheet, said one of the overlay sheets comprising a cured phenolic resin containing nonwoven polyester material.

8. A molded article according to claim 1 having from one to fifty percent by weight synthetic fibers to the total weight of the fibers in the layer.

9. A method of making a vehicle liner comprising: delivering fibers to a mold, a substantial majority of the fibers in at least one layer of the mold having a substantial majority of their surface areas substantially continuously coated with a binder material; molding the fibers in the mold to selectively densify portions of the delivered fibers to form a molded vehicle liner having a first region of a first density and a second region of a second density, the fibers being bound together by the binder in the shape of the liner.

10. A method according to claim 9 in which the fibers are wet laid into the mold, the binder being heat bondable, the fibers being heated within the mold to bind the fibers together.

11. A method according to claim 9 including the step of attaching a filler material to the fibers which are delivered to the mold.

12. A method according to claim 9 in which the fibers are air laid into the mold, the binder being heat bondable, the air laid fibers being heated within the mold to bind the fibers together.

13. A method according to claim 12 in which the fibers are heated prior to delivery to the mold.

14. A method according to claim 13 in which the mold is at a temperature below the heat distortion temperature of the binder on the coated fibers.

15. A method according to claim 9 in which the fibers are delivered to the mold in the form of a mat.

16. A method according to claim 15 in which the mat is heated prior to delivery to the mold.

17. A method according to claim 16 in which the mold is at a temperature below the heat distortion temperature of the binder on the coated fibers.

18. A method according to claim 9 including the step of delivering fibers on a cover sheet to the mold.

19. A method according to claim 18 in which the cover sheet is of a heat bondable material, the method comprising the step of heat bonding the fibers and cover sheet in the mold.

20. A method according to claim 18 in which the cover sheet is of a heat bondable material, the method comprising the step of heat bonding the fibers and cover sheet prior to delivery to the mold.

21. A method according to claim 18 in which the mold is at a temperature which is below the heat distortion temperature of the binder on the binder coated fibers.

22. A method according to claim 9 in which the fibers comprise plural layers of fibers.

23. A method according to claim 18 including the step of including a backing sheet in the vehicle liner with the fibers positioned between the cover sheet and the backing sheet.

24. A method according to claim 23 in which the majority of the fibers are wood pulp fibers.

25. A method according to claim 9 in which the article is molded to a density of from about 0.04 g/cc to about 1.2 g/cc.

26. A method according to claim 9 in which the article is molded to a density of from about 0.05 g/cc to about 0.6 g/cc.

27. A method of making a vehicle liner comprising: delivering fibers to a mold, a substantial majority of the fibers in at least one layer of the mold each having a substantial majority of their surface area continuously coated with a binder material; molding the fibers in the mold to densify the delivered fibers to a density of from about 0.04 g/cc to about 0.6 g/cc and form the vehicle liner; and removing the vehicle liner from the mold.

28. A method according to claim 27 in which the fibers are formed into a mat and heated to a temperature which is below the heat distortion temperature of the fibers to tack the fibers together prior to delivery to the mold.

29. A method according to claim 27 including the step of adhering at least one cover sheet to the molded fibers, the cover sheet including a thermoset material, the method comprises the step of heat curing the thermoset material and heat bonding the fibers.

30. A method according to claim 27 in which the fibers comprise plural layers of fibers.