KR20010108459A - Moldable composite article and method of manufacture - Google Patents

Abstract

An article is disclosed that includes a layer of moldable fabric having high stiffness when molded under heat or pressure. A variable compressive fabric layer, which may have a variable thickness when molded under heat or pressure, is bonded to the moldable fabric layer surface and the layers are made of the same thermoformable polymer.

Description

Moldable composite article and its manufacturing method {MOLDABLE COMPOSITE ARTICLE AND METHOD OF MANUFACTURE}

In the manufacture of articles containing polymeric materials having strength and toughness sufficient to function as automotive trunk liners, it is known to arrange layers of thermoformable materials having different properties in layers and to compress them under heat and pressure in the mold. At least one layer imparts strength and toughness and another layer produces sufficient volume for molding. U.S. Patent 5,298,319 discloses an automotive trunk liner made of a fibrous composite comprising an outer layer of nonwoven fabric consisting of polypropylene staple fibers and an intermediate layer of extruded polypropylene. Such known fibrous composites are assembled simultaneously with the extrusion of the intermediate polypropylene layer. The inner surfaces of the two outer nonwoven layers are bonded to the surface of the extruded polypropylene by the heat generated in the extrusion process and to the molten state of the adjacent surfaces that melt during this process. All three layers containing the same polymer, ie polypropylene, are used to promote ultimate recycling of the article.

There are several drawbacks to the procedure of this known art. Since the intermediate layer is extruded giving the bulk necessary for molding, the molded article has an essentially uniform thickness. Another drawback is that the fibrous composites must be assembled simultaneously with the interlayer extrusion.

Summary of the Invention

It is therefore an object of the present invention to provide an improved moldable fibrous composite that can be used to produce molded articles of varying thickness and density.

It is also an object of the present invention to provide an improved moldable fibrous composite made of layers that can be assembled continuously.

It is also an object of the present invention to provide an improved moldable fibrous composite made from compatible materials that can be easily recycled.

It is also an object of the present invention to provide a nonwoven fibrous composite that can be molded in a one step molding process.

It is also an object of the present invention to provide a nonwoven fibrous composite that can be used to mold articles having a high weight to thickness ratio.

It is also an object of the present invention to provide an improved moldable fibrous composite that easily takes the shape of a mold without breaking or tearing under molding under pressure and heating.

It is also an object of the present invention to provide an improved moldable fibrous composite that can be used to thermoform articles without the need to inject resin.

In order to achieve this object and overcome the problems of the known art, the present invention provides a moldable nonwoven fibrous composite and its manufacturing method. The nonwoven fibrous composite according to the invention has at least two functional layers made of the same nonwoven thermoformable polymer. Suitable polymers include polypropylene, polyvinyl chloride, polyvinyl acetate, polyamides, polyvinylalcohols, polyethylene, polyurethanes and polyesters. In one embodiment the layers are made of polyester. These composites can be used in the manufacture of automotive headliners, trunk liners, passenger compartment components, aberrations, furniture, sporting goods, and filtration products.

The selected polymer is made of two different fabrics with different mechanical components or physical properties. At least one fabric is a moldable fabric that has a relatively high strength and toughness upon final molding under heat or pressure. Other fabrics can have varying thicknesses and densities when molded under heat or pressure as variable compressive fabrics (variable thickness fabrics). Variable compression fabrics may be used in applications where the final article requires uniform thickness and density. Such variable compression fabrics are the subject of US Pat. No. 5,532,050. In another embodiment another layer constituting the facing fabric can be applied to the outer surface of the layer for the purpose of improving the composite molded article appearance. The fabric layer facing the functional layer can be assembled into a composite that can be shipped to the finished moldable article maker. The composite can be assembled by stacking and combining layers. "Composite" means a continuous layer stack regardless of whether the cohesion between layers is improved by chemical or physical means. Cohesion between adjacent layers of the composite can be enhanced by spray powder bonding, liquid dispersion / solution use, stitch bonding, flame lamination, the use of intermediate adhesive fabrics between functional layers, and mechanical needle punching.

Blends of selected fibers with a predetermined melting temperature range are included in one or two layers to affect the toughness of the final molded article and the adhesion between the composite layers. The resulting adhesion mechanism is described as "thermoplastic bonds" (US Pat. No. 5,456,976, column 3, lines 36-50). The composite sheet is then introduced into the mold and molded using heat or pressure to form the mold cavity to form the final article shape.

The present invention relates to composite articles, in particular moldable nonwoven fiber composite articles.

1 is a diagram of a moldable fibrous composite according to one embodiment of the present invention, showing the layer configuration.

2 is a schematic diagram of a system for manufacturing a molded article according to another embodiment of the present invention.

* Code Description

1 Composite 2 Variable Compression Fabric

3 Upper surface 4 Lower surface

5,8 Moldable fabrics 6,9 Upper surface

7,10 bottom surface 11,14 adhesive layer

12,15 Upper surface 13,16 Lower surface

17 Facing fabric layer 18 Upper surface

19 Lower surface 20 Adhesive layer

21 Upper surface 22 Lower surface

25,26 Formable Fabric 27 Face-to-Fabric

28 variable compression fabric 29,30,31,32 rolls

33 upper 34 lower

In accordance with the present invention an article is molded from a variable compressive fabric layer and a moldable fabric layer roll or sheet. In FIG. 2 the moldable fabrics 25, 26 are dispensed from the rolls 29, 32, the variable compressive fabric 28 is dispensed from the roll 31 and the facing fabric 27 is dispensed from the roll 30. These fabric layers are simultaneously supplied from each roll to forming means having an upper portion 33 and a lower portion 34.

An automotive headliner is formed by passing a variable compressive layer containing binder fibers and a moldable fabric layer through a compression mold having a cavity shaped in the form of a headliner when the composite roll is unwound. In order to achieve molding, the composite is exposed to elevated temperatures for a predetermined time and then molded in the mold. The binder fibers present in the separated layers soften or melt and mix under heat or pressure, and upon mold demolding, the fibers cool and cure to bond the layers.

According to another embodiment the moldable fabric layer, the variable compression fabric layer and the facing fabric layer are formed of a composite before being made into an article.

In Figure 1 various layers that make up the composite article of the present invention are shown. The thicknesses of the various layers are not drawn to scale.

In the composite article 1 of FIG. 1, the variable compression fabric layer 2 comprises a moldable fabric layer 5 having an upper surface 6 and a lower surface 7 and an upper surface 9 and a lower surface 10. Sandwiched between the moldable fabric layer 8 having the upper and lower adhesive layers 14, 11 disposed between the variable compressive fabric layer 2 and the moldable fabric layer 5, 8 so that the variable compressive layer 2 is formed. The upper surface 3 of the abutting the lower surface 16 of the adhesive layer 14 and the upper surface 15 of the adhesive layer 4 abutting the lower surface 7 of the moldable fabric layer 5 and the adhesive The upper surface 12 of the layer 11 abuts the lower surface 4 of the variable compressive layer 2 and the lower surface 13 of the adhesive layer 11 abuts the upper surface of the moldable fabric layer 8. The contact improves the contact and cohesion between the moldable fabric layers 5, 8 and the variable compression layer 2.

This embodiment is characterized in that the lower surface 19 of the facing fabric 17 abuts the upper surface 21 of the adhesive layer 20 and that the lower surface 22 of the adhesive layer 20 is moldable. The lower surface 19 of the facing fabric layer 17 by means of an adhesive layer 20 to improve the appearance of the composite outer surface and the outward direction of the molded article by abutting the upper surface 6 of the fabric layer 5 It can be deformed by applying it to the upper surface 6. An automotive headliner or trunk liner can be formed by passing the composite through compression molding means and subjecting it to heat or pressure for a time sufficient to allow the composite to have the shape of the mold cavity.

The basis weight of the moldable or cured fabric for use in the present invention is 4-18 oz / dy ² . The preferred range is 6-12 oz / yd ² . This range controls toughness in the final molding, optimizes handling and reduces manufacturing costs.

In another embodiment the variable compressed polyester fabric sheet is sandwiched between two moldable polyester sheets in the form of a needle punch felt to form a composite article. Needle punch felts are manufactured by Knowlton Nonwovens, Inc. (Utica, New York). Cohesion between adjacent sheets is improved by mechanical needle punching. The composite is then wound up on a storage roll. A decorative fabric layer, such as HOF AHMV8 printed stitchbond polyester or Foss needlepunch polyester, can be applied to the outer surface of the moldable polyester fabric layer.

Articles such as automotive trunk liners or head liners are formed in a mold under heat or pressure. Thereafter, the molded article is cooled to ambient temperature. U. S. Patent 5,298, 319 presents an apparatus and a basic forming procedure for making articles of the type contemplated by the present invention.

Different cohesion enhancing means can be used between different fabric layers of the same composite. For example, by disposing the adhesive layer therebetween, the cohesion between the facing fabric layer and the moldable fabric layer is improved and the cohesion between the moldable fabric layer and the variable thickness fabric layer by the needle punch is improved.

Alternatively, composites suitable for molding can be made from a single moldable fabric layer and a variable compression fabric layer. The facing fabric layer may be applied to the outer surface of the moldable fabric layer or the variable compression fabric layer. Cohesion between functional fabric layers can be improved by mechanical means such as needle punching or adhesion means such as spray powder bonding, liquid dispersions, solution use, flame lamination, adhesive layer placement.

The following examples show how the various structures of the present invention and the properties of the present structures are controlled by process variable changes. In the example below, a high loft multilayer in which the first and second stiffener layers blend selected fibers in a standard fabric blending facility, card the fibers into a nonwoven web and then needlepunch by 1000 pin needle penetration. It is made by a needlepunch process that is cross-wrapped to build a bat.

A moldable composite structure in which a variable compression fabric is sandwiched between two layers of moldable (stiffener) fabric is produced according to the following.

The three material layers are:

First Stiffener Layer 50% Fiber Innovation Technologies 3.5 Denier X 2 inches

2 inch crystalline polyester bicomponent binder fiber

50% Kosa 15 Denier X 3-inch Type 295 Polyester

Basic Weight-6 oz / yd ²

Needle Punch Composition (Stiffener Fabric)

Same fibers, blends and constructions as on the second stiffener layer

Basic Weight-9 oz / yd ²

Variable Compression Layer 50% Fiber Innovation Technologies 3.5 Denier X 2 in

Crystalline Polyester Bicomponent Binder Fiber

25% 6.7 dtex polyester

25% 17.0 dtex polyester

Basic weight-20 oz / yd ²

Thickness-20 mm

Vertical Wrap Configuration (Variable Compressed Fabric)

There is no adhesive layer between these material layers. Vertical Lap Products Variable compression fabrics are manufactured on Strudo machines (I.N.T., s.r.o., 460 05 Liberec, Karla Ca ka 302/22, Czech Republic).

Three polyester fibers, including one binder fiber, are blended on a standard textile fiber blending facility and carded into a nonwoven web to produce a variable compressive layer. The carded web is fed to a vertical wrap strudo machine which is folded or crimped to produce a vertically corrugated product. Thick products are passed through an oven and heated to 150 ° C. or higher to soften or melt the binder fibers and thermally bond them with other fibers in the blend to produce a high, thick three-dimensional product.

To produce the shaped article as defined above, the process includes laminating the fabric into a composite, preheating the composite to 400 ° F. for 8 minutes, placing the composite in the mold, opening the mold and removing the molded article. The mold is preheated to 300 ° F. for warm mold samples.

In the composite three-layer sample, the variable compressive layer is sandwiched between the first and second stiffener layers formed in the machine direction and the machine direction. Additional samples are formed in the machine and machine landscape directions using a mold that is not preheated at ambient temperature. Four samples prepared according to the above method were tested using non-reinforced and reinforced plastics and electrical insulation materials using the test method I-Three-point loading system utilizing a simply supported nonclinical central load of ASTM D 790-92. Flexural properties are tested under standard test methods.

The test results are shown in Table 1.

Flexural Test Results Sample Thickness (mm) Offset yield load (N) Yield Load AT 1 "(N) (%) Slope (N / m) Cold Tool SSLVCLFSL (Machine Direction) 16.50 20.9 21.2 101 5.72 Warm Tool SSLVCLFSL (Machine Direction) 17.50 21.5 22.5 105 5.65 Cold Tool SSLVCLFSL (Machine Landscape) 17.50 24.5 29 118 6.46 Warm Tool SSLVCLFSL 17.75 22.4 28.5 127 5.90

* SSL = second stiffener layer

VCL = Variable Compression Layer

FSL = first stiffener layer

The operating range providing adequate toughness for the molded composite of the present invention is the offset yield load of 13-26 Newtons. The yield load at 1 "should be 90-140% and the slope should be 2.5-7.0 N / mm.

Products of the present invention require elevated stiffness that is suitable for use as automotive headliners. "High stiffness" is defined by the flexural test results in Table 1. The molded headliner bears its load and the weight of the internal dome lights and sun visor over an interval of up to 8 feet in the case of minivans, with exposure up to three days evaluated in standard environmental resistance tests on the headliner. High stiffness is required to avoid bending or cracking at temperatures between 40 and 185 ° F. The product shall not bend to the point where it cracks the headliner and cannot support the weight of the added headliner component. Also, cracks in the headliner are seen through the decorative fabric in the headliner and therefore aesthetically unacceptable. When stressed above the limit, the product of the present invention bends and cracks, making it unsuitable for automotive headliners. The "low modulus" product does not crack when broken and does not exhibit the stiffness needed to support additional components, especially during use in environmental resistance tests. Therefore, low modulus products are not suitable for use as automotive headliners.

Claims (20)

Comprising a moldable nonwoven layer with high stiffness when molded under heat or pressure, offset yield load of 13-26 Newtons, yield load of 90-140% 1 inch, under ASTM D-790-92 Test Method I The variable compressive nonwoven layer having a slope of 2.5-7.0 N / mm, wherein the moldable nonwoven layer has a top and bottom surface, and includes a variable compressed nonwoven layer that can have a variable thickness when molded under heat or pressure; And a silver upper and lower surface, wherein the lower surface of the moldable nonwoven layer is a variable compression nonwoven layer bonded to the upper surface and the layers are made of a thermoformable polymer material. The article of claim 1, wherein the moldable nonwoven and the variable compression nonwoven are comprised of polyester. The article of claim 2, wherein the bond between the moldable layer and the variable compressive layer is enhanced by mechanical means. 4. The article of claim 3, wherein the mechanical means for increasing interlayer cohesion is needle punching. 3. An article according to claim 2, wherein the bond between the moldable layer and the variable compressive layer is enhanced by means of adhesion. 3. An article according to claim 2, wherein a facing fabric layer having an upper and a lower surface is applied to the moldable fabric layer such that the lower surface of the facing fabric layer is adjacent to the upper surface of the moldable fabric layer. 3. The article of claim 2, wherein a facing fabric layer having an upper and a lower surface is applied to the variable compression fabric layer such that the lower surface of the facing fabric layer is adjacent to the lower surface of the variable compression fabric layer. Including two moldable nonwoven layers with high stiffness when molded under heat or pressure, offset yield loads from 13 to 26 Newtons, yield loads from 1 inch to 90 to 140%, ASTM D-790-92 Test Method A variable compression nonwoven layer having a slope of 2.5 to 7.0 N / mm under I, wherein the moldable nonwoven layer has an upper and a lower surface, and which may have a variable thickness when molded under heat or pressure, the variable compression A nonwoven layer is sandwiched between an upper surface of one moldable fabric layer and a lower surface of another moldable fabric layer and the layers are made of a thermoformable polymer material. 10. The article of claim 8, wherein the moldable nonwoven and the variable compression nonwoven are comprised of polyester. 10. The article of claim 9, wherein the bond between the moldable layer and the variable compressive layer is enhanced by mechanical means. 10. The article according to claim 9, wherein the bond between the moldable layer and the variable compressive layer is enhanced by adhesive means. 10. The article of claim 9, wherein a facing fabric layer having an upper and a lower surface is applied to the moldable fabric layer such that the lower surface of the facing fabric layer is adjacent to the upper surface of the moldable fabric layer. 9. The article of claim 8, wherein a facing fabric layer having an upper and a lower surface is applied to the variable compression fabric layer such that the lower surface of the facing fabric layer is adjacent to the lower surface of the variable compression fabric layer. Comprising a moldable nonwoven layer with high stiffness when molded under heat or pressure, offset yield load of 13-26 Newtons, yield load of 90-140% 1 inch, under ASTM D-790-92 Test Method I A variable compressive nonwoven layer having a slope of 2.5-7.0 N / mm and having a variable thickness when formed under heat or pressure, the variable compressive nonwoven layer having an upper and a lower surface, the moldable A nonwoven layer is sandwiched between an upper surface of one variable compressed nonwoven layer and a lower surface of another variable compressed nonwoven layer and the layers are made of a thermoformable polymeric material. 13-26 Newton's offset yield load, 90-140% 1-inch yield load, slopes of 2.5-7.0 N / mm and high stiffness under ASTM D 790-92 Test Method I when molded under heat or pressure A nonwoven fibrous composite having a plurality of layers including a moldable nonwoven layer and a variable compressive nonwoven layer that may have a variable thickness, the article having a variable thickness suitable for automotive headliners, wherein the layers are made of a thermoformable polymer. Goods. 16. The article of claim 15, wherein the variable thickness fabric layer is sandwiched between two moldable fabric layers. 16. The article of claim 15, wherein the moldable fabric layer is sandwiched between two variable compression fabric layers. 16. The article of claim 15, wherein the moldable nonwoven and the variable compression nonwoven are comprised of polyester. The article of claim 15, wherein the article is in the shape of an automobile trunk liner. The article of claim 15, wherein the article is in the form of an automobile headliner.