JP2000037803A - Laminated sheet and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To impart fire retardancy and strength required for adhesion or the like by high frequency or ultrasonic wave by sequentially laminating a face layer composed of a thermoplastic resin, an expanded body layer composed of a thermoplastic resin, a base fabric composed of a fiber selected from natural fiber and cellulose fiber, and an adhering resin layer. SOLUTION: A laminated sheet is formed by sequentially laminating a face layer composed of a thermoplastic resin, an expanded body layer composed of a thermoplastic resin, a base fabric composed of one or more fibers selected from natural fiber and cellulose fiber, and an adhering resin layer. An elastic material excellent in designing effect and feeling of touching, for example an olefinic thermoplastic elastomer, is preferably used for the face layer. A form of the base fabric is preferably a woven fabric, wherein a natural fabric such as a cotton, a kapok cotton, a hemp or the like, or a cellulose fiber such as a viscose rayon, an acetate or the like is preferable. A polypropylene, a polyethylene, a polystyrene, a urethane resin or the like is preferable for the expanded body.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laminated sheet used for covering interior materials and daily necessities of automobiles and furniture such as sofas and chairs which require welding or sewing by high frequency waves or ultrasonic waves, and a laminate sheet thereof. It relates to a manufacturing method.

2. Description of the Related Art Conventionally, vinyl chloride resin has been used as a material for products that require high frequency welding, ultrasonic welding, sewing and the like. However, in recent years, environmental pollution due to harmful gas generated by combustion of vinyl chloride resin has been emphasized, and materials that do not cause such pollution are desired. Further, when used as an automobile interior material, there is a problem of fogging due to volatilization of a plasticizer. Further, tonneau covers used for hatchback vehicles, station wagon vehicles, trunks of RV vehicles, and the like are required to have improved strength and flame retardancy (100 mm / min in the MVSS standard).

The use of olefinic materials as one means of preventing environmental pollution by vinyl chloride resins has been studied. However, since olefin-based materials are easily flammable in themselves, halogen-based or non-halogen-based flame retardants are used particularly for automotive interior materials. In the case of (1), there was a problem that a sufficient expansion ratio and strength could not be obtained. In addition, there is also a problem that the cost of the product increases because the flame retardant is expensive.

[0003]

SUMMARY OF THE INVENTION According to the present invention, flame retardancy can be obtained without using a flame retardant. Further, the present invention has the necessary strength for bonding and sewing by high frequency or ultrasonic waves, and can be used for a wide range of applications. It is an object of the present invention to provide a laminated sheet and a method for producing the same.

[0004]

According to the first aspect of the present invention, there is provided a laminated sheet comprising a surface layer made of a thermoplastic resin, a foam layer made of a thermoplastic resin, and natural fibers and fibrous fibers. Wherein a base cloth made of one or two or more fibers selected from the group consisting of: and an adhesive resin layer are laminated in this order.

[0005] A method for manufacturing a laminated sheet according to claim 2 is a method for manufacturing a laminated sheet according to claim 1, wherein when a foam layer, a base cloth, and an adhesive resin layer are laminated,
The base fabric is superimposed on the foam layer, the adhesive resin is melt-extruded on the base fabric surface, and the molten adhesive resin is permeated to the back surface of the base fabric, and the base fabric and the foam layer are bonded by the adhesive resin. It is characterized by adhesive lamination.

The surface layer made of a thermoplastic resin serves as the surface of a product using the same, and it is preferable to use an elastic material having excellent design effects and tactile sensation. Examples of such an elastomer include an olefin-based thermoplastic elastomer having polypropylene as a hard segment and ethylene as a soft segment (such as EPM), or having a small amount of a diene component together with ethylene (such as EPD). ), Mixtures thereof, and those partially crosslinked by adding an organic peroxide thereto.

The olefin resin used as the surface layer is T
It is extruded into a sheet by a die or an inflation die. The surface on the front side of the product may be embossed by a known method to enhance the design effect.

The hardness of the surface layer is generally preferably in the range of 50 to 98 in JIS A hardness, and the thickness is 25 to 1000 μm.
m, preferably 100 to 500 μm.
If necessary, pigments, light stabilizers, ultraviolet absorbers, antistatic agents, fragrances, deodorants, fungicides, and the like may be added to the surface layer resin.

An adhesive layer or an adhesive resin layer may be provided on the side of the surface layer which is in contact with the foam layer, and a top coat layer for imparting scratch resistance may be laminated on the outside of the surface layer. , May be printed. Further, a nonwoven fabric or the like may be laminated to improve tactile sensation.

It is known that the flammability of a sheet containing only an olefin resin is different between the longitudinal direction and the lateral direction of the sheet. This characteristic is considered to be related to the crystal part and the molecular orientation of the olefin-based resin sheet that is uniaxially stretched after extrusion or molding. That is, since the molecules are oriented in the longitudinal direction of the sheet (extrusion direction or stretching direction at the time of extruding the sheet), the amorphous portion adjacent to the crystalline portion is linearly arranged, and the burning rate in this direction is high. In other words, it is considered that the burning speed is reduced because the crystal portion becomes a wall in the lateral direction of the sheet and exists as a plurality of obstacles for burning. Also, due to such molecular orientation, the tensile strength of the sheet itself is large in the longitudinal direction and small in the lateral direction.

As described above, the flammability and strength directionality of the sheet can be solved by laminating the base cloth. The base fabric laminated on the foam layer is made of one or more fibers selected from natural fibers and fibrous fibers, and the fibrous fibers are obtained by chemically treating plant fibers using pulp. Which burn themselves but have lower combustion energy than the resin of the surface layer and the foam layer. In addition, it is considered that it itself has hygroscopicity, and the combustion energy becomes smaller due to the moisture absorption. Therefore, it is considered that the layer acting on the surface layer and the foam layer acts in a direction in which the combustion energy is reduced, thereby lowering the combustion rate.

A woven fabric is preferred as the form of the base fabric, and a plain woven fabric is more preferred. As natural fibers, vegetable fibers include seed fibers such as cotton and kapok cotton, and bast fibers and vein fibers such as hemp, and animal fibers include silk, wool, camel hair, and rabbit hair.

For fibrous fibers, viscose rayon, polynosic rayon, cupra rayon, acetate,
Triacetate, acetylated soup and the like. Of the above, rayon-based regenerated artificial fibers are preferably used.

In order to increase the strength of the base fabric, it is effective to mix synthetic fibers within a range that does not increase the flammability of the entire laminated sheet. In this case, the mixed fiber or the mixed spun yarn may be, for example, a yarn obtained by twisting several fibers and twisting them together with the above-mentioned fiber, and a woven fabric using the yarn. It may be a woven fabric with a fiber yarn.

A foam layer is laminated between the surface layer and the base fabric in order to provide a cushioning property and a soft touch feeling on the product surface. Such foams include polypropylene,
Olefin resins such as polyethylene, polystyrene, styrene resins such as styrene-maleic anhydride copolymer,
Various thermoplastic elastomers that can be foam-molded into a sheet, such as urethane-based resins, may be mentioned. Of these, olefin-based resins that are lightweight and easy to mold are preferable.

The foam is preferably crosslinked with an electron beam or a chemical crosslinking agent in order to improve the heat resistance and strength of the foam. The expansion ratio is 5 in terms of cushioning and tactile sensation.
It is preferable that the thickness is about 50 to 50 times and the thickness is about 0.5 to 5 mm.

The method of bonding and laminating the surface layer and the foam layer is as follows.
The surface layer resin may be laminated by melt extrusion on the foam layer surface, but it is preferable to use an adhesive or the like in order to prevent the foamed structure from being crushed by the heat of the molten resin.

The adhesive resin layer is thermoplastic and has high-frequency heating adhesiveness and ultrasonic heating adhesiveness. The high-frequency heating is dielectric heating, and the electromagnetic field to be used is 1 MHz or more, usually 10 to 40 MHz, and is melted and bonded by internal heat generation of the adhesive resin. Therefore, the adhesive resin needs to be a dielectric, and the lower the melting point, the easier it is to adhere. The characteristics of such a resin may be any as long as it has an equal amount of positive and negative charges and each molecule is an electric dipole and has a polar group. Olefin resins are typical examples of such materials, and specific examples thereof include EVA, EMMA, and EVA.
MA and the like, and urethane-based and amide-based materials besides olefin-based materials.

Ultrasonic heat bonding is also internal heat generation, but can be applied to all thermoplastic resins because it utilizes heat generated by forced vibration of ultrasonic waves. Therefore, a resin as needed can be used. The thickness of the adhesive resin layer is preferably from 50 to 1,000 μm, more preferably from 100 to 500 μm.

The method for producing a laminated sheet according to the present invention comprises, as one of the steps, a method of laminating a foam layer on which a surface layer may be laminated, and a base cloth on which an adhesive resin is previously laminated by melt extrusion with an adhesive. There is a way to match. However, in the present invention, in order to simplify the manufacturing process and increase the adhesive strength between the foam layer and the base cloth, the base cloth is superimposed on the foam layer, and the adhesive resin is melt-extruded onto the base cloth to form the base cloth. The melted adhesive resin is allowed to penetrate to the back surface of the base cloth in the gaps between the fibers, and the foam resin layer and the base cloth are bonded by the molten resin.

If the molten adhesive resin does not easily penetrate in its natural state, it can be passed through a pinch roll or the like to give an appropriate pressing force to assist the penetration of the molten resin and the development of adhesive strength.

In the adhesion between the base fabric and the foam layer by melt extrusion of the adhesive resin, an olefin resin which is easily melt-extruded is preferably used as the adhesive resin, and its melt index is 0.5 to 10 at 190 ° C. Is preferred. The thickness of the extruded sheet-like adhesive resin is preferably 100 to 1000 μm.

The base fabric used in the method of bonding the above-mentioned adhesive resin by melt extrusion requires a gap between the fibers to allow the molten resin to penetrate to the back surface. It is preferably about books / inch.

When a foam having no surface layer is used, the surface layer may be laminated in the following step.

(Function) According to the laminated sheet of the present invention, a surface layer made of a thermoplastic resin, a foam layer made of a thermoplastic resin, and one or two kinds selected from natural fibers and fibrous fibers Since the base fabric made of the above fibers is laminated, the base fabric having lower combustion energy than the surface layer reduces the vertical burning speed of the surface layer, and is made flame-retardant.

Further, since the above-mentioned base cloth is laminated on the foam layer, the strength required for bonding and sewing by high frequency or ultrasonic waves is given, and by changing the material of the base cloth and the density of the fibers, Flammability and strength can be designed freely. Further, since the laminated sheet of the present invention uses an olefin-based thermoplastic elastomer as the surface layer and natural fibers or fibrous fibers as the base fabric, no harmful gas is generated even when it is burned, thereby avoiding environmental health problems. You.

According to the method for producing a laminated sheet of the present invention,
The adhesive resin penetrates to the back surface of the base fabric and adheres to the foam layer, and the resin is impregnated between the fibers of the base fabric, so that the base fabric and the foam layer are firmly adhered to each other, and thereafter, various processes are performed. A laminated sheet having a strength that can withstand the above is obtained.

[0028]

Embodiments of the present invention will be described below. Surface layer: 60% olefin-based thermoplastic elastomer (Mitsui Chemicals, trade name "Millastomer 8030N") and 20% polypropylene (Tokuyama, trade name "MS624")
And polyethylene (Mitsubishi Chemical Corporation, trade name "LF-480
M ") was used as a resin in the form of pellets.

Foam layer: polyethylene foam sheet (manufactured by Sekisui Chemical Co., Ltd., trade name “Softlon IF08008”, thickness)
0.8 mm, expansion ratio 8 times) Polypropylene foam sheet (manufactured by Sekisui Chemical Co., Ltd., trade name "SPVA2502", thickness 2 mm, expansion ratio 25 times) Base cloth: The one shown in Table 1 was used.

[0030]

[Table 1]

Adhesive resin layer: Those shown in Table 2 were used.

[0032]

[Table 2]

(Examples 1 to 8; Comparative Examples 1 and 2) Production of Laminated Sheet The above surface layer and foam layer, the base fabric shown in Table 1, and Table 2
The combination of the adhesive resin shown in Table 3 was used, and the resin of the surface layer was melt-extruded at a temperature of 220 ° C. from a single screw extruder (φ65 mm) through a T die (430 mm width), and an embossing roll and a rubber pinch roll were used. Then, the sheet was passed while being pressed together with the foam sheet, and laminated, thereby producing a laminate of a surface layer having an embossed surface and a foam sheet. A base cloth is superimposed on the foam sheet surface of the laminate, the adhesive resin is extruded onto the base cloth surface in the same manner as described above, and the surface is pressed while being pressed between a smooth mirror-finished roll and a rubber pinch roll,
The laminated sheet was obtained by bonding the base cloth and the foamed sheet with the adhesive resin penetrating the base cloth. The surface temperature of the emboss roll and the mirror roll was 45 ° C.

Evaluation method (1) 10% stretch strength Using a No. 1 type dumbbell punching die specified in JIS-K6301, three laminated sheets were punched out in the longitudinal direction (extrusion direction) and in the horizontal direction, and test pieces were cut out. The strength at 10% elongation was read by a tensile tester, and the average value was taken as the strength. (2) Flammability In accordance with MVSS302, ten test pieces were cut out in each of the vertical and horizontal directions to obtain test pieces. The maximum value of the burning rate (cm / min) when this test piece was burned was defined as flammability, and 10 cm
/ Min or less was judged to be good. (3) Adhesion The foam sheet / base cloth or the foam sheet / adhesive resin layer was peeled off by hand, and the material fracture area on the foam sheet surface was visually read and evaluated according to the following criteria. ◎: 80 to 100% ：: 50 to 79% Δ: Less than 50% The above results are shown in Table 3.

[0035]

[Table 3]

(Examples 9 to 15) The surface layer and the foam layer, the base cloth shown in Table 1, and the adhesive resin shown in Table 2 were combined as shown in Table 4 to obtain the adhesive resin layer. A laminated sheet was produced in the same manner as in Example 1 except that the thickness was as shown in Table 4, and the results of evaluating the adhesiveness are shown in Table 4.

[0037]

[Table 4]

As is clear from Table 3, all of the examples according to the present invention have higher strength than those of Comparative Example 2 which does not use the base fabric, and the combustion speed in the vertical direction decreases, and It turns out that it is near and flame retardant. In the case of Comparative Example 1, since the base fabric used was PET yarn, the strength was high, but the flammability in the vertical and horizontal directions was high.

From Table 4, it can be seen that the adhesive resin layer having a large thickness has a large adhesive strength, but the resin layer having the same thickness has a high melt index even when the resin layer has the same thickness. It turns out that adhesiveness falls when it is low.

[0040]

The laminated sheet of the present invention has the above-mentioned structure. By using a base cloth made of fibers selected from a specific material, the flame retardancy, which was difficult to solve only with the resin layer, is improved. And the strength required for heat bonding and sewing by high frequency or ultrasonic waves can be obtained. Further, by changing the material of the base cloth and the density of the fibers, the design of the flammability and the strength can be freely performed. Furthermore, since the laminated sheet of the present invention uses a material that does not generate harmful gas even when burned, it does not have a problem of environmental hygiene and can be used for a wide range of uses such as interior materials of automobiles, covering of daily necessities and furniture. Further, according to the method for producing a laminated sheet of the present invention, a laminated sheet having excellent adhesive strength between a base fabric and a foam layer and having strength capable of enduring various processes can be produced by a simple production process.

Continued on front page F term (reference) 4F100 AJ00C AK01A AK01B AK01D AK03 AK04 AK07 AL05 AL09 BA04 BA07 DG01C DG11C DG12 DJ01B EH232 GB33 GB71 GB81 JB16A JB16B JJ07 JK01 JL11D

Claims (2)

[Claims] 1. A surface layer made of a thermoplastic resin, a foam layer made of a thermoplastic resin, a base fabric made of one or more fibers selected from natural fibers and fibrous fibers, A laminated sheet characterized by being laminated with an adhesive resin layer in this order. 2. The laminating of the foam layer, the base cloth and the adhesive resin layer, laminating a base cloth on the foam layer and melt-extruding the adhesive resin on the surface of the base cloth. 2. The method for producing a laminated sheet according to claim 1, wherein the base sheet and the foam layer are adhered and laminated with the adhesive resin.