JPH1017837A - Sheet for dielectric heating bonding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a sheet which enables the bonding of members within a very short time by magnetic induction heating by sticking a specified powder to at least either surface of a thermoplastic resin sheet. SOLUTION: A conductive powder (e.g. iron powder) is stuck to at least either surface of a thermoplastic resin sheet (e.g. PE sheet). The sheet for bonding is used, for example, in producing an automotive ceiling material by setting a resin board, as a base material, molded in the form of an automotive ceiling on the bottom tool 11 of an electromagnetic compression die 10, laying the sheet 3 for bonding and a nonwoven polyester fabric as a skin material on the resin board, descending the top force 12, pressing the nonwoven polyester cloth against the resin board through the sheet 3, and applying electromagnetic waves to the assemblage to instantaneously heat the conductive powder and to thereby soften the thermoplastic resin sheet to bond the resin board to the cloth 5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet for induction heating bonding used for bonding a carpet and an insulator for an automobile floor covering and an automobile interior base material and a skin material, for example.

[0002]

2. Description of the Related Art Recently, a high-frequency or electromagnetic wave is applied to a thermoplastic resin sheet mixed with a conductive powder, and the conductive powder in the sheet is induction-heated to soften the thermoplastic resin sheet. There is interest in induction heating bonding for bonding members. Conventionally, in order to produce a thermoplastic resin sheet mixed with such conductive powder, a method of heat-softening and kneading the thermoplastic resin and the conductive powder in an extruder and extruding a sheet from a T-die, or A method of sheeting a heat-softened thermoplastic resin mixed with a conductive powder with a calendar roll has been applied.

[0003]

In the above-mentioned conventional method, it is difficult to uniformly knead the thermoplastic resin and the conductive powder because of the difference in specific gravity between the thermoplastic resin and the conductive powder. Therefore, a thermoplastic resin sheet in which the conductive powder is uniformly dispersed can be obtained. That the surface of the screw or calender roll of the extruder is worn by the conductive powder, for example, when a surface material such as non-heat-resistant polypropylene fiber nonwoven fabric is adhered to one surface of the thermoplastic resin sheet, When the conductive powder of the plastic resin sheet is induction-heated, there is a problem that the nonwoven fabric is heated by the conductive powder and the nonwoven fabric is thermally damaged.

[0004]

SUMMARY OF THE INVENTION The present invention, as a means for solving the above-mentioned conventional problems, provides a sheet for induction heating and bonding in which conductive powder is adhered to one or both surfaces of a thermoplastic resin sheet. is there.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The thermoplastic resins used in the present invention include, for example, polyethylene, polypropylene, ethylene-propylene copolymer, polyvinyl chloride, polyvinylidene chloride, polystyrene, polyester, ethylene-vinyl acetate copolymer and the like. It is. The conductive powder used in the present invention is, for example, iron powder, aluminum powder, copper powder, stainless steel powder and the like.

The thermoplastic resin is formed into a sheet by a method of extruding a sheet from an extruder through a T-die, a method of sheeting the softened thermoplastic resin by a calender roll, or the like. In order to adhere the conductive powder to one or both surfaces of the thermoplastic resin sheet, a method of magnetically adsorbing the conductive powder by a magnetic roll in a heat-softened state of the sheet to press and adhere the sheet to the surface of the sheet, and heating the sheet A method in which the conductive powder is introduced into an electrostatic field in a softened state, the conductive powder is sprayed, and the conductive powder is attached to the sheet surface by Coulomb force is applied.

After the conductive powder is adhered to one or both surfaces of the sheet, if necessary, the surface of the sheet is further pressed by a pressing roller or the like to fix the conductive powder on the surface of the sheet. Excess conductive powder present on the sheet surface is removed by, for example, a magnet or air blow.

When the conductive powder is adhered to one side of the sheet for induction heating bonding of the present invention thus produced, for example, the conductive powder-adhering surface is placed on the back of a carpet for automobile floor coverings. Further, an insulator such as a polyurethane foam sheet, felt or the like is superimposed on the lower side of the sheet, and an electromagnetic wave is applied to the sheet to induction-heat the conductive powder attached to the sheet. By the induction heating of the conductive powder, the surface of the thermoplastic resin sheet to which the conductive powder is attached is softened. Such softening of the surface of the thermoplastic resin sheet to which the conductive powder is attached is performed almost instantaneously. If the insulator is pressed against the carpet in this state, the insulator is pressed against the carpet.

[0009] Since the heating of the sheet is performed only on the side where the conductive powder is attached, the high temperature does not reach the side of the sheet where the carpet is adhered. Therefore, even if the carpet is made of a fiber having poor heat resistance, such as a polypropylene fiber, the carpet is not seriously damaged. When conductive powder is attached to both sides of the sheet, for example, cardboard, resin impregnated polyurethane foam, resin board, polystyrene foam and other substrates and glass fiber sheet, bamboo fiber sheet, palm fiber sheet, It is used for bonding to a reinforcing sheet such as a hemp fiber sheet, bonding the base material or a laminate of the base material and the reinforcing sheet to the skin material, bonding the clip mounting bracket to the base material, and the like.

Example 1 A polyethylene sheet (1) was extruded from a T-die (7) shown in FIG. 1 in a heat-softened state, and a magnetic roll (1) was maintained while the polyethylene sheet (1) was kept in a heat-softened state. Iron powder (2), which is a conductive powder according to (8, 8)
(200 mesh) is applied to both sides of the polyethylene sheet (1) and pressed. The polyethylene sheet (1) having the iron powder (2) adhered to both sides then passes between the electromagnets (9, 9) to remove excess iron powder adhering to both sides of the sheet (1). In this way, an induction heating bonding sheet (3) having iron powder (2) adhered on both sides at a rate of 100 g / m ² is produced.

[0011] A resin board (4) as a base material formed in the shape of an automobile ceiling is set on the lower mold (11) of the electromagnetic wave crimping mold (10) shown in FIG. The sheet (3) and the polyester non-woven fabric (5) as the skin material are overlapped, and the upper mold (12) is lowered, and the resin board (4) is passed through the induction heating bonding sheet (3) as shown in FIG. The polyester non-woven fabric (5) is pressed to apply an electromagnetic wave to instantly heat the iron powder (2) on both sides of the induction heating bonding sheet (3),
The polyethylene sheet (1) is softened, and the resin board (4) and the polyester nonwoven fabric (5) are bonded by the polyethylene sheet (1). In this way, as shown in FIG. 4, a sheet for induction heating and bonding to the surface of the resin board (4)
An automobile ceiling material (6) to which a polyester nonwoven fabric (5) is bonded via (3) is manufactured.

Example 2 A calender roll shown in FIG.
(27) Ethylene-vinyl acetate copolymer sheet (21)
At the same time, and the sheet (21) is pressure-bonded to the back surface of the carpet (24) made of polypropylene fiber. While the ethylene-vinyl acetate copolymer sheet (21) is kept in a softened state by heating, an aluminum powder (22) (150 mesh), which is a conductive powder, is shaken from the vibrating sieve (28) into the sheet (21).
At this time, an electrostatic field is formed by interposing an electrostatic grid (29), and the aluminum powder (22) is adhered to the surface of the sheet (21) by Coulomb force. The ethylene-vinyl acetate copolymer sheet (21) is further passed through an air blower (30) to remove excess aluminum powder adhering to the surface of the sheet (21). In this way, an induction heating bonding sheet (23) partially adhered with aluminum powder (22) at a rate of 70 g / m ^{2 on} one side is adhered to the back side of a raw carpet web (24).
A) is manufactured.

The raw carpet web (24A) is cut into a predetermined size and heated to soften the induction heating bonding sheet (23), and is immediately set in a molding die (31) shown in FIG. Cold press forming is performed between the mold (32) and the upper mold (33). The carpet molding thus formed (26A)
Is set on the electromagnetic wave crimping type (31A) shown in FIG. The lower part (32A) of the electromagnetic wave crimping type (31A) has an induction electromagnetic coil (34
A) is installed, and the felt (25) as an insulator is set in advance. The upper mold (33A) of the electromagnetic wave crimping die (31A) is lowered to press the carpet molding (26A) against the felt (25) via the induction heating and bonding sheet (23) and to apply electromagnetic waves to the induction. The aluminum powder (22) of the heat bonding sheet (23) is instantaneously heated, the ethylene-vinyl acetate copolymer sheet (21) is softened from the lower surface, and a felt (25) is formed on the carpet molding (26).
A) is bonded via the induction heating bonding sheet (23).
At this time, since the high temperature of the aluminum powder (22) is not directly applied to the carpet (24) bonding surface side of the ethylene-vinyl acetate copolymer sheet (21), the carpet (24) is not thermally damaged. . In this way, as shown in FIG. 8, a carpet (26) for an automobile floor mat formed in a shape conforming to the automobile floor shape is manufactured.

[0014]

According to the sheet for induction heating bonding of the present invention, the conductive powder adhered to one or both surfaces of the thermoplastic resin sheet is instantaneously heated to a high temperature by electromagnetic wave induction heating. Can be done. Further, since the conductive powder adheres to the surface of the thermoplastic resin sheet, the screw and calender roll of the extruder do not wear out unlike the case where the conductive powder is mixed with the thermoplastic resin. Further, if the conductive powder is adhered to only one surface of the thermoplastic resin sheet, even if the surface material or the like adhered to the surface opposite to the surface to which the conductive powder is adhered is made of a material having poor heat resistance, The material is not seriously damaged.

[Brief description of the drawings]

1 to 4 show an embodiment 1 of the present invention.

FIG. 1 is a drawing showing a process for producing a sheet for induction heating bonding.

FIG. 2 is an explanatory view before a crimping step.

FIG. 3 is an explanatory view of a crimping process.

FIG. 4 is a perspective view of a ceiling material. FIGS. 5 to 8 show an embodiment 2 of the present invention.

FIG. 5 is a process chart for producing a sheet for induction heating bonding.

FIG. 6 is an explanatory view before a crimping step.

FIG. 7 is an explanatory view of a crimping process.

FIG. 8 is a perspective view of a carpet for a car floor.

[Explanation of symbols]

 1,21 Thermoplastic resin sheet 2,22 Conductive powder 3,23 Induction heating bonding sheet

Claims (1)

[Claims] 1. A sheet for induction heating bonding, wherein a conductive powder is adhered to one or both surfaces of a thermoplastic resin sheet.