WO2001023176A1

WO2001023176A1 - Method of forming a sheet of reinforced product

Info

Publication number: WO2001023176A1
Application number: PCT/US2000/026531
Authority: WO
Inventors: Randy J. Dempsey; Anthony L. Rockwell; William A. Kunkler, Sr.; Gary J. Jakubcin
Original assignee: Owens Corning
Priority date: 1999-09-27
Filing date: 2000-09-27
Publication date: 2001-04-05
Also published as: AU7721700A

Abstract

A method of forming a sheet of reinforced product (10) includes applying binder to a layer of fibrous material (14), drying (28) the binder applied to the layer of fibrous material, applying a layer of reinforcement material (30) to the fibrous layer after the binder is dried, and bonding a layer of cover material (34) to the reinforcement material, thereby forming the sheet of reinforced product.

Description

METHOD OF FORMING A SHEET OF REINFORCED PRODUCT

TECHNICAL FIELD AND INDUSTRIAL APPLICABILITY OF THE INVENTION This invention relates in general to a method of forming a sheet of reinforced fibrous product for use in the manufacturing of molded contoured fibrous products, such as for example, vehicle headliners.

BACKGROUND OF THE INVENTION It is well known to use fibrous material, and more specifically glass fiber insulation, for heat energy and acoustical insulation in molded contoured products, such as vehicle headliners. The fibrous insulation is generally provided in a laminate sheet or roll form which can be molded to a desired contoured shape in a conventional mold, such as a heat press mold. The laminate sheet may also include an outer cover material, such as fabric, to function as a protective covering. The fibrous material of the laminate sheet provides strength and rigidity to the molded products due to the relatively high tensile strength of the glass fibers.

In one known method of manufacturing a laminate sheet, the fibrous material is impregnated with a binder additive having resin and a synthetic rubber, such as latex, mixed therein. Binder is applied to loose fibrous material to promote cohesion between contacting points of adjacent fibers, thereby joining the loose pack of fibers into a cohesive sheet or batt of insulation material. The latex additive provides flexibility to the laminate sheet after molding to help prevent the sheet from cracking when slightly flexed. Although the latex additive provides flexibility, it has been found that laminate sheets having the latex additive may not be flexible enough for some applications such that the laminate sheet will fracture or crack if bent or flexed too much. Another problem with the addition of the latex is that it can reduce the tensile strength of the fibrous material. The latex additive also inherently promotes the retention of heat during molding, leading to longer mold production periods. It is also known to produce a laminate sheet having a layer of fibrous material and layers of reinforcement material adhered thereto, such as that disclosed in U.S. Patent No. 5,068,001 to Haussling. The reinforcement material is a relatively thin porous mat formed of a plurality of randomly dispersed fibers. The fibers are fused together to sufficiently form a cohesive mat. The reinforcement material provides strength and rigidity to the laminate sheet and helps to retain the laminate sheet in the desired molded contoured shape. To form the laminate sheet, the fibrous layer is impregnated with a binder, such as resin, to fuse the fibers together. The fibrous layer is fed between mats of reinforcement material and dried to temporarily hold the fibrous layer and reinforcement mats together. This temporary laminate is then advanced to a coating station where the reinforcement mats are coated on their exposed surfaces with uncured resin. The resin impregnates the mats and their interface with the fibrous layer. The resin is spray coated onto the reinforcement mats such that the amount of resin applied to the mats is sufficient to bond the mat to the fibrous material. Thus, it can be seen that the conventional method includes adding the reinforcement material to the base layer of fibrous material either with a separate adhesive or prior to the binder application so that the reinforcement material will be adhered to the base layer of fibrous material. A cover layer and a mold release layer are then brought into contact with their adjacent surfaces while the resin is still wet. Thus, the resin coating on the reinforcement mats adheres the fibrous layer to the mats as well as adhering the cover layer and the mold release layer to the reinforcement mats. The laminate is then passed through rollers and is introduced into a heated contoured mold which subjects the laminate to heat and pressure to cure the resin, thereby forming a molded product. Although this product has been found satisfactory for some applications, it is preferable that the fibrous layer have a stiffer integrity. In some applications, such as vehicle headliners, the laminate sheet is turned on its edge prior to insertion into a mold. Therefore, the laminate sheet should have enough structural integrity to stand upright and not sag prior to insertion into the mold. It would be desirable to produce a reinforced laminate sheet having a higher structural integrity.

SUMMARY OF THE INVENTION

The above objects as well as other objects not specifically enumerated are achieved by a method of forming a sheet of reinforced product. The reinforced product is ideally suited for being molded into vehicle headliners. The method includes first providing a layer of fibrous material, such as glass fibers. A binder is applied to the layer of fibrous material. The binder is preferably dried so that the binder is not cured. A layer of reinforcement material is applied to the fibrous layer after the binder has dried. A layer of cover material is then bonded to the reinforcement material, thereby forming the sheet of reinforced product. Preferably, the reinforcement material and cover material include polymer material which is melted and blended together to bond the layer of cover material to the layer of reinforcement material.

Various objects and advantages of this invention will become apparent to those skilled in the art from the following detailed description of the preferred embodiment, when read in light of the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 is a schematic elevational view illustrating an apparatus for carrying out the method of forming a sheet of reinforced product, in accordance with the present invention. Fig. 2 is an exploded cross-sectional view of the reinforced product taken at line 2- 2 of Fig. 1.

DETAILED DESCRIPTION AND PREFERRED EMBODIMENTS OF THE INVENTION

Referring now to the drawings, there is schematically illustrated in Fig. 1 an apparatus for forming a reinforced product 10 according to the present invention. The reinforced product 10 is generally formed into a flat sheet which can be rolled up into a roll 12 and transported to a molding station (not shown) for molding the reinforced product 10 into a desired contoured three-dimensional shape. The reinforced product 10 can be molded and used for any desired product application, such as for example, vehicle headliners. The reinforced product 12 includes a fibrous layer 14 which can be initially supplied in a roll 16. The fibrous layer 14 can be any suitable fibrous material having desirable insulating properties and can be made from a wide range of inorganic and organic materials, including mineral fiber such as fibers of glass, rock, slag and basalt, and including fibers of thermoplastic materials such as polymers. Preferably, the fibrous layer 14 is comprised of glass fibers which are fused together. The fibers can be fused together by being impregnated with a binder, such as for example, a phenolic resin binder, and more preferably phenol-urea- formaldehyde, which is then cured. Of course, the binder can have other additives, such as fire retardants and color additives. The fibrous layer 14 is preferably impregnated with a relatively small amount of binder, such as less than 6 percent by weight, enough to provide integrity to the fibrous layer 14. The fibrous layer 14 can be supplied in any suitable density, thickness, width, and length. For automotive headliners, the fibrous layer 14 preferably has a density within the range of from about 1 to about 5 pounds per cubic foot (pcf).

To form the reinforced product, the supply of fibrous layer 14 is first directed into an applicator, indicated generally at 18, illustrated in Fig. 1. The applicator 18 impregnates the fibrous layer 14 with an additional relatively large amount of uncured binder, as will be explained below. Note that the initially supplied fibrous layer 14 can be manufactured off-site such that the binder used during the formation process is dry and cured when the method of the present invention, as described below, is implemented. Of course, the fibrous layer 14 can be supplied without binder or with uncured binder. The binder applied in the applicator 18 can be similar to the binder which is initially applied to the supply of fibrous layer 14, such as for example, a phenolic resin binder, and more preferably phenol-urea- formaldehyde.

The applicator 18 can apply the binder by any suitable method, such as for example, by spraying or immersing the fibrous layer in a tank. Preferably, the applicator 18 applies the binder to the fibrous layer 14 via a binder foam, such as described in U.S. Patent No. 5,008,131. For example, the applicator 18 can include a rotating foraminous drum 20 and a foam discharge head 22. The fibrous layer 14 is directed between the drum 20 and the discharge head 22, which define a nip region 24. As the fibrous layer 14 passes by the discharge head 22, binder foam is directed from the discharge head 22 through the compressed region of the fibrous layer 14 in the nip region 24. Preferably, the fibrous layer is compressed in the nip region 24 to a thickness within the range of from about 5 to about 20 percent of the thickness of the uncompressed fibrous layer 14. The discharge head 22 can be supplied with the binder foam from a foamer 26. The binder foam can also be directed into the fibrous layer 14 through the use of suction or a vacuum type applicator. The use of binder foam helps facilitate a uniform coating on all the fibers of the fibrous layer 14, and applies the coating with a minimum amount of carrier medium, such as water. The compression of the fibrous layer 14 at the nip region 24 in cooperation with the foraminous drum 20 helps to insure that the foam will pass directly into the fibrous layer 14 rather than leaking around it. The applicator 18 may include multiple discharge heads 22 and drums 20. The applicator 18 may also include pairs of rollers 27 to assist in pulling or directing the fibrous layer 14 through the applicator 18. After exiting the applicator 18, the fibrous layer 14 is directed into a dehydrator oven 28. Preferably, the dehydrator oven 28 does not cure the foam binder applied by the applicator 18 but removes substantially all of the water, resulting in an uncured product having about 10 to about 25 percent binder by weight of the combination binder and fibrous layer 14. More preferably, the binder is about 21 percent by weight of the combination binder and fibrous layer 14. Preferably, the oven 28 dries the moisture from the binder so that only between about 2 percent to about 7 percent moisture is left. It has been found that a moisture content of about 6 to about 7 percent gives the binder a slightly tacky characteristic. The dehydrator oven 28 can be any suitable oven which dries the binder without curing it. For example, the oven 28 can be gas fired, a radio frequency dryer, or a microwave dryer. After exiting the dehydrator oven 28, a layer of reinforcement material 30 is directed into contact with the fibrous layer 14. The reinforcement material 30 is preferably supplied in a roll 32 having a width which is approximately equal to the width of the fibrous layer 14. The reinforcement material 30 and the fibrous layer 14 are pulled or directed together in a rightward direction, as viewing Fig. 1. The reinforcement material 30 is preferably a porous relatively thin fibrous mat, wherein the fibers have a relatively high tensile strength and are fused together at their contacting points. The fibers are oriented in a plane defined by the mat. As an example, the reinforcement material 30 can be made of elongated glass fibers which can be woven or non-woven. More preferably, the reinforcement material 30 is comprised of fibers having a polyester core and an outer nylon sheath, the reason for which will be explained below. It has been found that a suitable reinforcement material is manufactured by Akzo Nobel and sold under the trademark "COLBACK". The reinforcement material 30 can have any suitable thickness and density to provide a desired strength and flexibility characteristic, such as for example, between the range of from about 20 g/m²to about 100 g/m². The porosity of the reinforcement material 20 can also be any suitable amount, such as for example, having an average of about 0.5 inch (1.27 centimeter) openings existing through the layer of reinforcement material 30. Although the fibrous material 14 can be slightly tacky due to the moisture content of the binder, the reinforcement material is loosely adhered to the fibrous layer 14 by mechanical interconnection of the fibers of the fibrous layer 14 and reinforcement material 30. Preferably, a layer of cover material 34 is directed into contact with the exposed layer of reinforcement material 30, as shown in Fig. 1. The cover material 34 can be supplied in a roll 36, as shown in Fig. 1, and is preferably the width of the fibrous layer 14 and reinforcement material 30. The cover material 34 can be any suitable facing or fabric material for aesthetic, decorative, or protective purposes. The cover material 34 can be, for example, polyester, nylon, rayon, cloth, cotton, or any blend thereof. The cover material 34 functions as a protective covering.

Preferably, both the cover material 34 and reinforcement material 30 have plastic or polymer material integral or dispersed therein which can be melted and blended together to adhere or laminate the cover material 34 to the reinforcement material 30. Preferably, the polymer material is a polyamide material or adhesive. However, any suitable polymer material which can be introduced into the cover material 34 and the reinforcement material 30 and which can be melted and blended together can be used. As shown in Fig. 1, a hot plate 38 can be used to melt the polyamide adhesive. The reinforcement material 30 and cover material are directed across the hot plate 38 which is at an adequate temperature to melt the polyamide adhesive. As an example, the cover material 34 can be a cloth trim material having fragments of polyamide adhesive scattered throughout the cloth trim material. The fragments can be applied to the cloth or trim material by any suitable means, such as by dot coating, spraying or atomizing. The reinforcement material 30 can be comprised of fibers having a polyester core and an outer nylon sheath. As the reinforcement material 30 and the cover material 34 are directed across the hot plate 38, the fragments of polyamide adhesive in the cloth trim will melt and blend with the outer nylon sheath of fibers of the reinforcement material 30, thereby laminating the cover material 34 to the reinforcement material 30. As used herein, the terms "melt", "melted", and "melting" include heating the material to soften it to the extent that it can adhere to another material. It is to be understood that other means of bonding the cover material 34 to the reinforcement material 30 can be used, such as for example, infrared heating. The reinforced product 10 preferably also includes an optional temporary backing layer 40 which is placed against the cover material 34 and rolled up into the roll 12 of the reinforced product 10. The backing layer 40 provides a temporary barrier to help separate the adjacent layers of cover material 34 and fibrous layer 14 when rolled up. The roll 12 is unrolled by the customer. The backing layer 40 is preferably peeled off before the reinforced product 10 is molded. The temporary backing layer 40 can be any suitable material, such as kraft paper, for protecting the adjacent layers of cover material 34 and fibrous layer 14.

After the reinforced product 10 is rolled into the roll 12, the reinforced product can be transported to a customer for use in a conventional mold (not shown), such as a heat press mold, to shape the reinforced product to a desired contoured shape. Typically, the roll 12 is shipped in bags which may reduce air curing of the binder in the product 10.

The reinforced product 10 may also include an optional second layer of reinforcement material, indicated by broken lines 42 of Fig. 1. The second layer of reinforcement material 42 can be supplied in a roll 44 and is directed into contact with the fibrous layer 14 in a similar manner to the way the reinforcement material 30 is applied. The second layer of reinforcement material 42 is directed against the fibrous layer 14 prior to entry into the applicator 18. The second layer of reinforcement material 42 can be similar to the reinforcement material 30, such as for example, a porous relatively thin fibrous mat, wherein the fibers have a relatively high tensile strength and are fused together at their contacting points. Alternatively, the reinforced product 10 can be made such that it includes the second layer of reinforcement material 42 and not the reinforcement material 34.

The principle and mode of operation of this invention have been described in its preferred embodiments. However, it should be noted that this invention may be practiced otherwise than as specifically illustrated and described without departing from its scope.

Claims

WHAT IS CLAIMED IS:

1. A method of forming a sheet of reinforced product (10) comprising the steps of:

(a) providing a layer of fibrous material (14); (b) applying binder to the layer of fibrous material (18);

(c) drying the binder applied to the layer of fibrous material (28);

(d) applying a layer of reinforcement material (30) to the layer of fibrous material after the binder is dried; and

(e) bonding a layer of cover material (30) to the reinforcement material, thereby forming the sheet of reinforced product.

2. The method of Claim 1 , wherein the binder is dried (28) to the layer of fibrous material (14) such that the binder contains less than about 7 percent moisture by weight.

3. The method of Claim 1, wherein the layer of fibrous material (14) is provided with an initial cured binder less than 6 percent by weight.

4. The method of Claim 1, wherein the layer of fibrous material (14) is comprised of glass fibers.

5. The method of Claim 1, wherein the binder is applied to the layer of fibrous material (14) by an applicator (18) which impregnates the fibrous material with binder foam.

6. The method of Claim 1 , wherein the binder is dried (28) by directing the layer of fibrous material (14) through a radio-frequency oven.

7. The method of Claim 1, wherein the reinforcement material (30) is a porous fibrous mat.

8. The method of Claim 1, wherein the cover material (34) and reinforcement material (30) have polymer material, and wherein the layer of cover material and the reinforcement material are bonded together by melting and blending the polymer material.

9. The method of Claim 8, wherein the polymer material is melted by directing the layers of cover material (34) and reinforcement material (30) over a heated plate (38).

10. The method of Claim 8, wherein the polymer material of both the cover material (34) and the reinforcement material (30) is a polyamide.

11. The method of Claim 1 further comprising the steps of:

(a) applying a removable layer of backing material (40) adjacent to either the cover material (34) or the fibrous layer (14); and (b) rolling (12) the sheet of reinforced product (10) such that the layer of backing material is between adjacent layers of the cover material and the fibrous layer.

12. The method of Claim 1 further comprising the step of applying a second layer of reinforcement material (42) to the fibrous layer (14) prior to applying binder to the layer of the fibrous material.

13. The method of Claim 12, wherein the second layer of reinforcement material

(42) is a porous fibrous mat.

14. A method of forming a sheet of reinforced product (lθ)comprising the steps of:

(a) providing a layer of fibrous material (14) impregnated with cured binder; (b) impregnating the layer of fibrous material with binder (18);

(c) drying the binder applied to the layer of fibrous material without curing the binder (28);

(d) applying a layer of reinforcement material (30) to the fibrous material after the binder is dried, the reinforcement material having polymer material therein; (e) applying a layer of cover material (34)adjacent the layer of reinforcement material, the cover material having polymer material therein;

(f) heating (38) the layer of reinforcement material and layer of cover material to cause the polymer material of the reinforcement material and cover material to melt and blend together, thereby bonding the layer of reinforcement material to the layer of cover material;

(g) applying a layer of removable backing material (40) adjacent to either the cover material or the fibrous layer, thereby forming a sheet of reinforced product; and

(h) rolling (12) the sheet of reinforced product such that the layer of backing material is between adjacent layers of the cover material and the fibrous layer.

15. The method of Claim 14, wherein the binder is dried (28) to the layer of fibrous material (14) without curing the binder such that the binder contains less than about 7 percent moisture by weight.

16. The method of Claim 14, wherein the layer of fibrous material (14) is provided with an initial cured binder that is less than about 6 percent by weight.

17. The method of Claim 14, wherein the binder is applied to the layer of fibrous material (14) by an applicator (18)which impregnates the fibrous material with binder foam.

18. The method of Claim 14, wherein the reinforcement material (30) is a porous fibrous mat.

19. The method of Claim 14, wherein the polymer material is melted by directing the layers of cover material (34) and reinforcement material (30) over a heated plate (38).

20. The method of Claim 14 further comprising the step of applying a second layer of reinforcement material (42) to the fibrous layer prior to impregnating the layer of fibrous material (14) with binder.