JP2015042448A - Laminated sheet, molded article and production method of the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laminated sheet which has electromagnetic wave-shielding performance and at the same time has sound absorbency, a heat insulating property, and a shape maintaining property, and for which a time-consuming working step such as cutting and bonding a shield component is unnecessary, and a molded article such as an electromagnetic wave-shielding under panel formed of the laminated sheet.SOLUTION: A laminated sheet is formed by bonding a water impermeable skin material to a surface of an electromagnetic wave-shielding material formed by covering a surface or both surfaces of a sheet-like fiber material with a highly conductive metal, and bonding a rigid thermoplastic sheet to the other surface thereof. In producing the laminated sheet and a molded article thereof, the water impermeable skin material formed of a film or the like is laminated on a surface of the electromagnetic wave-shielding material, the rigid thermoplastic sheet composed of a high basis weight felt or the like formed by mixing a thermally fusible fiber is laminated on the other surface thereof, and the skin material, the electromagnetic wave-shielding material, and the rigid thermoplastic sheet are integrally molded by heating and compressing the laminated sheet.

Description

  The present invention is a laminated sheet suitably used for an under panel or the like of an automobile, and has both electromagnetic shielding properties and shape maintaining properties, and is an interior material or furniture material for automobiles, railway vehicles, aircraft, ships, houses, etc. The present invention also relates to a laminated sheet that can also be used as a molded product, a molded product comprising the same, and a manufacturing method.

  When a battery is mounted under the floor of an automobile in an electric vehicle, the problem is that electromagnetic waves generated when sending a large amount of current to the motor are emitted from the battery. It is necessary to wear an electromagnetic shielding material to suppress.

  Electromagnetic waves can be prevented by completely storing the battery in a metal housing, but using metal in a case that encloses a large number of batteries is an additional weight even in electric vehicles where weight is just a problem. Cause an increase. Therefore, although a resin casing is used, since a normal resin transmits electromagnetic waves, a resin to which metal fibers are added at a certain ratio is used, or the inner surface is painted with a shielding paint. Also, molded metal plates and metal meshes are often inserted, but these are attached to cases and panels molded with resin so that the battery is covered in the direction in which it is desired to prevent electromagnetic waves from being emitted. used.

  However, it is very costly to use a resin having shielding properties for the entire casing, and sufficient shielding performance cannot be obtained by a method of coating the inner surface with a shielding paint. For metal shields, the weight increases significantly. Although it is possible to reduce the weight by making the metal mesh, it is difficult to reduce the weight because it is necessary to give the resin molded product as a housing strength in order to fix the metal shielding material. Since the metal shield material and the housing are separately manufactured and combined, the production cost is also increased.

  As a substitute for a metal plate or a metal mesh, a woven fabric (see Patent Document 1) plated, a nonwoven fabric mixed with plating fibers (see Patent Document 2), and the like have been proposed as a lightweight and flexible electromagnetic shielding material. However, in order to make these shield parts, they are fixed and mounted by methods such as cutting, stapling on a plastic molded box or plate frame, heat fusion with a high frequency welder, or adhesive bonding. Therefore, it is difficult to obtain a stable shielding characteristic.

  In addition, as a material having both electromagnetic shielding performance and sound absorption performance, a material (see Patent Documents 3 and 4) in which a low density felt and an aluminum foil are bonded is also proposed. Then, a process of attaching to the wall or ceiling is necessary.

JP-A-10-209671 JP 2009-277952 A JP-A-8-306482 JP 2011-181714 A

  The present invention has been made in view of the above circumstances, and has an electromagnetic shielding performance, and at the same time, has a sound absorbing property, a heat insulating property, a shape maintaining property, and is a time-consuming process of cutting and pasting a shield component. Laminated sheets that do not require processes, molded products made of them, especially tire noise while driving a car, impact noise of stepping stones, noise generated from various devices such as engines and power steering, heat is transmitted to the outside of the vehicle interior An object of the present invention is to provide an electromagnetic wave shield under-panel that can be suppressed and reduced and that can be easily and reliably manufactured for covering and protecting the lower surface of a battery case to improve the aerodynamic characteristics of a vehicle body.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors bonded a lightweight and flexible electromagnetic shielding material with a rigid thermoplastic sheet and impermeable to the electromagnetic wave generation source side surface. It has been found that the above-mentioned problems can be solved at once by attaching a skin material and further providing a protective layer on the surface on the outer side of the vehicle body, thereby completing the present invention.

That is, the present invention is as follows.
(1) An electromagnetic shielding material in which a highly conductive metal is coated on one side or both sides of a sheet-like fiber material, a non-permeable skin material is laminated on one side, and a rigid thermoplastic sheet is laminated on the other side And a laminated sheet in which these are integrally bonded.
(2) The laminated sheet according to (1), wherein the rigid thermoplastic sheet has a protective layer on the opposite side of the laminated surface with the electromagnetic wave shielding material.
(3) The laminated sheet according to (1) or (2) above, wherein the rigid thermoplastic sheet has a three-point bending strength (deflection length of 10 mm) of 5 N or more.
(4) The rigid thermoplastic sheet is a felt in which 5 to 50% by weight of heat-fusible fiber is mixed, and the basis weight is in the range of 800 to 2,000 g / m ² . The laminated sheet according to any one of the above.
(5) A molded article formed by using the laminated sheet according to any one of (1) to (4) above.
(6) An automobile under panel, wherein the protective sheet is formed so as to face the outside of the vehicle body using the laminated sheet according to any one of (2) to (4).

(7) An electromagnetic shielding material in which a highly conductive metal is coated on one or both sides of a sheet-like fiber material, a non-permeable skin material is laminated on one side, and a rigid thermoplastic sheet is laminated on the other side A method for producing a laminated sheet and a molded product, wherein the laminated sheet is heated and compressed to integrally form a skin material, an electromagnetic wave shielding material, and a rigid thermoplastic sheet.

In the laminated sheet of the present invention, since a rigid thermoplastic sheet is bonded to the electromagnetic shielding material, the electromagnetic shielding material can be provided with rigidity, easy processability, sound absorption, and heat insulation, and the opposite surface is impermeable to water. Since the protective skin material is bonded, the electromagnetic wave shielding performance is hardly deteriorated due to the penetration of water into the electromagnetic wave shielding material.
Furthermore, by providing a protective layer on the rigid thermoplastic resin sheet, the protective layer can provide the laminated sheet with an effect of mitigating the impact caused by jumping stones and the like, and the laminated sheet can be prevented from being broken by the impact.

  The laminated sheet has thermoplasticity and shape maintenance, so it can be easily formed into a desired shape by thermoforming, and when it is produced, it can be produced into molded products such as automobile under panels. Can do. Therefore, it is not necessary to perform a time-consuming processing step such as cutting the electromagnetic shielding material and attaching it to the housing as in the prior art.

  As the rigid thermoplastic sheet, by using a high-weight felt mixed with heat-fusible fibers, a laminated sheet that is light and easy to process and is difficult to peel off each material can be obtained.

  By using a molded product made of laminated sheets as an electromagnetic shielding under panel, tire noise while driving a car, impact sound of stepping stones, driving noise and heat generated from various devices such as engines and power steering are transmitted to the vehicle interior. Various effects can be obtained such as suppressing or reducing the above, or covering and protecting the lower surface of the battery case, or improving the aerodynamic characteristics of the vehicle body. The laminated sheet and the molded product of the present invention can also be used as interior materials and furniture materials for automobiles, railway vehicles, aircraft, ships, houses, and the like.

  According to the method for producing a laminated sheet and molded product of the present invention, these materials can be integrally formed by thermoforming a laminated sheet obtained by laminating a skin material, an electromagnetic shielding material, and a rigid thermoplastic sheet. The manufacturing process can be simplified.

2 is a schematic cross-sectional view illustrating a configuration of a laminated sheet of Example 1. FIG. 3 is a schematic cross-sectional view showing a configuration of a laminated sheet of Example 2. FIG.

  The laminated sheet of the present invention is formed by laminating at least a water-impermeable skin material and a rigid thermoplastic sheet to an electromagnetic shielding material in which a highly conductive metal is coated on one or both sides of a sheet-like fiber material. It is.

<Electromagnetic wave shielding material>
Examples of the sheet-like fiber material used for the electromagnetic wave shielding material of the present invention include flexible fiber materials such as woven fabrics, knitted fabrics, and non-woven fabrics. Woven fabric) is preferably used.
Although the thickness of a sheet-like fiber raw material is not specifically limited, Preferably it is 0.01-2 mm. By setting the thickness of the sheet-like fiber material to 0.01 mm or more, a sufficient amount of metal can be attached to impart electromagnetic wave shielding performance. Moreover, if the thickness of a sheet-like fiber raw material is 2 mm or less, workability will not be impaired remarkably. More preferably 0.01 to 1 mm, and still more preferably about 0.01 to 0.5 mm. The mass per unit area (basis weight) is lighter better, from the point of view of strength and shielding performance, preferably 10 to 250 g / ^{m 2,} more preferably 20 to 200 g / ^{m 2,} more preferably 20 150 g / m ² .

  The fibers constituting the sheet-like fiber material are preferably polyester fibers such as polyethylene terephthalate and polymethylene terephthalate, and general-purpose fibers such as nylon fibers, acrylic fibers, polypropylene fibers, and polyethylene fibers from the viewpoint of cost. Polyester fibers are preferred from the standpoints of metal adhesion to the sheet-like fiber material and dimensional stability.

The method of coating the highly conductive metal on one or both sides of the sheet-like fiber material is not particularly limited, and may be a known method such as electroless plating, vapor deposition, sputtering, and the shielding performance of the electromagnetic shielding material. And the type of material, etc., are selected as appropriate. The coating amount of the highly conductive metal is preferably ³ to 15 g / m ² with respect to the sheet-like fiber material. If the coating amount is too small, the electromagnetic shielding property is inferior, and if the coating amount is too large, the metal falls off. Inconvenience occurs.

  Examples of the highly conductive metal include copper, silver, gold, nickel, iron, permalloy and the like, and these metals can be used alone or in combination of two or more. Among these, it is desirable to use copper or silver that exhibits high shielding characteristics. When copper is used, the shielding performance tends to be reduced due to oxidation of copper. Therefore, it is preferable to coat the fiber material with copper and further coat the copper with a metal other than copper such as nickel.

<Skin material>
The skin material needs to be impermeable. This is because if the skin material is water permeable, the water that has entered the laminated sheet corrodes the metal in the electromagnetic wave shielding material, thereby inhibiting the shielding effect.

  Examples of the material constituting the skin material include a thermoplastic resin film such as polyurethane, polypropylene, and polyester, which has water resistance and excellent followability, or a water resistant paint coating film.

  Although the thickness of a skin material is not specifically limited, Preferably it is 0.01-2 mm, More preferably, it is 0.01-1 mm, More preferably, it is 0.01-0.5 mm. If the thickness of the skin material is 0.01 mm or more, it is difficult to break, and if it is 2 mm or less, the flexibility of the laminated sheet can be secured.

<Rigid thermoplastic sheet>
The rigid thermoplastic sheet is used for imparting rigidity to the laminated sheet, but also has an effect of imparting heat insulation and sound absorption, and is laminated on the opposite surface of the skin material with the electromagnetic wave shielding material interposed therebetween. The rigid thermoplastic sheet preferably has a three-point bending strength of 5 N or more at a deflection of 10 mm as its characteristics. More preferably, the three-point bending strength when the deflection is 10 mm is 10 N or more, and particularly preferably 20 N or more. Here, the three-point bending strength can be determined by measuring the bending strength when the sheet is bent by 10 mm in accordance with JIS K7074-1988 (bending test method for carbon fiber reinforced plastic). When the rigidity is insufficient, the shape maintaining performance of the laminated sheet or molded product is lowered.

  As the rigid thermoplastic sheet, a thermoplastic resin mixed with an inorganic filler, a thermoplastic resin foam, a felt, or the like is preferably used because it has rigidity and sound absorption performance. As a material for the rigid thermoplastic sheet, a general-purpose thermoplastic material such as nylon, polyester, polypropylene, or polyurethane is desirable from the viewpoint of being able to be molded at a molding temperature that does not give an excessive load to the electromagnetic wave shielding material and cost.

  Of these, felt is preferable from the viewpoint of light weight and excellent thermoformability. As the fiber constituting the felt, general-purpose fibers such as polyester fiber, nylon fiber, and polypropylene fiber are preferable from the viewpoint of availability, recyclability, and cost, and a fiber in which these fibers are mixed may be used. Recycled fibers of these fibers are also preferably used.

  The rigid thermoplastic sheet may be laminated as it is, but a chip-resistant protective layer is preferably provided on the opposite side of the laminated surface with the electromagnetic wave shielding material. As a material constituting the protective layer, a material having an effect of reducing the impact of the flint is preferable, and examples thereof include films, nonwoven fabrics, felts, foams and the like. A coating film may be formed by applying a protective coating or the like on the outside of the rigid thermoplastic sheet. Among these, felt is preferable from the viewpoints of moldability and sound absorption performance. The material constituting the protective layer can be used alone, but, for example, by applying a protective coating on the outside of the non-woven fabric or felt, the chipping performance against the flint is improved. Is also possible.

  The felt used for the rigid thermoplastic sheet and the protective layer can be a needle punched nonwoven fabric, a water jet punched nonwoven fabric, or the like as a raw material. Reactive felt formed from wool and felt mixed with anti-wool are also preferably used. These felts preferably contain heat-fusible fibers from the viewpoints of moldability, sound absorption performance, and shape maintenance performance.

  The fiber length and fineness of the fibers constituting the felt are not particularly limited and can be appropriately determined depending on the use of the molded product. However, the fiber length is preferably 10 mm or more, more preferably 10 to 100 mm, and particularly preferably 20 to 80 mm. By using short fibers having a fiber length of 10 mm or more, the tangled short fibers are less likely to fall off from the felt. On the other hand, the longer the fiber length is, the better the sound absorption is, but it is preferable to be 100 mm or less because the spinning property from the card tends to be inferior. A fineness of 0.5 to 30 dtex, preferably 1 to 20 dtex, particularly 1 to 10 dtex is preferably used. These fibers can be used alone or in admixture of two or more. It is also possible to use a mixture of thermoplastic short fibers having the same kind or different kinds of fibers and having different fineness and fiber length. In this case, the mixing ratio of the fibers is arbitrary and can be appropriately determined according to the use and purpose of the laminated sheet.

  The ratio of the heat-fusible fiber mixed with the felt varies depending on the shape and size of the molded product using the laminated sheet, but is preferably 5 to 50% by weight of the entire felt, more preferably 10 to 10%. 40%. By setting the ratio of the heat-fusible fiber to 5% by weight or more, it is possible to impart an appropriate rigidity to the rigid thermoplastic sheet and easily form the laminated sheet into a desired shape. Moreover, if the heat-fusible fiber is mixed at a maximum of 50% by weight, sufficient adhesiveness can be imparted, and there is no fear that the sound absorption performance will be remarkably lowered by reducing the proportion of other fibers. .

  As the heat-fusible fiber, a fiber made of a polymer having a melting point of 150 ° C. or less is preferable, and the fiber can be molded without melting other fibers constituting the felt. The heat-fusible fiber may be selected from rigid thermoplastic sheet constituent fibers, or a known thermoplastic short fiber may be used. As the thermoplastic short fiber, one or more fibers made of a low melting point polymer such as a low melting point polyester fiber, a polypropylene fiber, a polyethylene fiber, a linear low density polyethylene fiber, an ethylene-vinyl acetate copolymer fiber are used. Alternatively, a core-sheath type composite fiber having a high melting point polyester such as polyethylene terephthalate as a core part and a low melting point polyester copolymerized with isophthalic acid or the like as a sheath part can be used. As the heat-fusible fiber, it is preferable to use a fiber made of a polymer having a melting point lower by 20 to 150 ° C. than other fibers constituting the felt.

  A rigid thermoplastic sheet in which heat-fusible fibers are mixed with the fibers that make up the felt. After both fibers are mixed with a cotton spreader and spreader, it is hung on a card machine to form a web, which is then laminated with a cross layer. The body can be made by a method of melting a heat-fusible fiber with a hard cotton machine or a needle punch, or by a method of heat-treating a fiber that has been spread and mixed into a mold using high-pressure air. it can. By melting the heat-fusible fiber by heat treatment, the entangled portion of the fiber can be bonded, and there is an effect of improving the strength of the felt and preventing the fiber from falling off. The fiber length of the heat-fusible fiber is not particularly limited, and can be appropriately determined depending on the compatibility with other thermoplastic short fibers and the use of the molded product. Usually, the fiber length is 10 to 100 mm, particularly 20 to 80 mm. preferable.

The basis weight of the rigid thermoplastic sheet is preferably in the range of 800 to 2,000 g / m ² . If the basis weight is 800 g / m ² or more, there is no fear of insufficient rigidity even if the preferable thickness (2 mm to 15 mm) of the sheet is taken into consideration, and if the basis weight is 2,000 g / m ² or less, the moldability decreases. There is no fear of doing. More preferably, it is 900-1,500 g / m < ² >, Most preferably, it is 1,000-1,300 g / m < ² >.

  When felt is used for the protective layer, it is preferable to make the density higher than that of the rigid thermoplastic sheet because the chip resistance is improved.

  Each fiber constituting the laminated sheet of the present invention may be subjected to water repellent treatment and flame retardant treatment as necessary. Examples of the water-repellent treatment method include a method of coating or impregnating a known water-repellent treatment agent such as a silicone resin or a fluororesin on a fiber constituting the felt or the produced felt, a method of reacting a silane coupling agent, and the like. It is done.

  As a flame retardant treatment method, a known flame retardant such as a phosphorus flame retardant, a halogen flame retardant, or a metal hydroxide compound (magnesium hydroxide, calcium hydroxide, etc.) is coated on the fiber constituting the felt or the produced felt. Or the method of impregnation etc. are mentioned. An acrylic resin emulsion or an acrylic resin solution containing a flame retardant may be coated or impregnated.

  The thickness of the laminated sheet of the present invention is preferably 5 to 30 mm, more preferably 10 to 25 mm, from the viewpoints of economy, ease of processing, and the like.

  A sound-absorbing material or a sound insulating material can be appropriately laminated on the laminated sheet of the present invention, and a vibration-damping paint or the like can be applied to the surface.

  Next, an example of the manufacturing method of the lamination sheet and molded article of this invention is demonstrated.

  When manufacturing the laminated sheet of the present invention, the above-mentioned skin material, electromagnetic wave shielding material, and rigid thermoplastic sheet are laminated in this order to produce an original sheet. The stacking order may be reversed. The original sheet may be in a non-adhered state or an adhesive state. Moreover, when manufacturing the laminated sheet which has a protective layer, a rigid thermoplastic sheet and a protective layer may be laminated | stacked separately, and the rigid thermoplastic sheet which provided the protective layer beforehand may be laminated | stacked. By using a sheet provided with a protective layer in advance, it is possible to produce a laminated sheet that hardly causes adhesion failure or peeling at the time of molding.

When the skin material, the electromagnetic wave shielding material, and the rigid thermoplastic sheet constituting the laminated sheet are bonded together, a known adhesion method can be used. For example, methods such as adhesion by an adhesive, adhesion by thermal fusion, adhesion by ultrasonic waves, and the like can be given.
As the adhesive, powder of high-temperature adhesive resin such as nylon or polyester and powder of low-temperature adhesive resin such as EVA (ethylene vinyl acetate copolymer) can be used, and these resins are dispersed on the material, It can be bonded by stacking another material on top of it and heat-treating it.
Further, a net, a film, a nonwoven fabric, or a fiber made of a low melting point resin can be interposed between the respective materials, and can be bonded by heat treatment.
In addition, a heat-meltable resin such as a modified polyamide resin previously transferred to an arbitrary shape such as a dot shape can be used for the skin material, and the skin material and the electromagnetic shielding material can be bonded by heat treatment. .

  The laminated sheet of the present invention can be obtained by subjecting an original sheet to hot press molding using a known method such as a calender roll or a mold.

  The molded product comprising the laminated sheet of the present invention can be obtained as a molded product in which the raw material is integrally molded by thermoforming the original sheet by a method such as clamping with a heating mold using a known molding machine. Can do. In the thermoforming, the original sheet may be preliminarily heat-treated to form a laminated sheet, or the original sheet may be bonded simultaneously with the thermoforming. If the material is molded after heat treatment in advance, it becomes easy to mold, and a molded product that is firmly integrated with each material can be obtained.

  The heating temperature during heat treatment or thermoforming is preferably 140 to 200 ° C. If the heating temperature is too low, the molding tends to be insufficient, and the shape retainability may be lowered, and peeling with time may occur. On the other hand, if the heating temperature is too high, the material may be thermally deteriorated. In addition, what is necessary is just to determine heat processing time and a compression pressure suitably according to the required characteristic of a lamination sheet or a molded article.

  Since the laminated sheet of the present invention is excellent in sound absorption / heat insulation, shape maintenance, electromagnetic wave shielding and non-water permeability, it can be formed into an appropriate size and shape according to the purpose and use. That is, after a planar laminated sheet is manufactured, it can be cut into an appropriate size and shape and used as an interior material such as a wall material or a ceiling material. For example, interior materials for automobiles, wagons, ships, aircraft, houses, buildings, etc .; civil engineering and construction materials; Etc.

  Moreover, after shape | molding a lamination sheet in the molded product of desired shape, an edge part is cut off and it can use for various uses as an electromagnetic wave shielding material. Among various applications, it can be suitably used as an under panel for automobiles. When used as an under panel for automobiles, the laminated sheet of the present invention is molded so that the protective member faces the outside of the vehicle body, and is arranged so that the skin material faces the engine side. It is possible to improve the chip resistance against.

  EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited only to a following example.

Example 1
As an electromagnetic shielding material, a metal-plated fabric was prepared by electrolessly plating copper and nickel in this order on both sides of a polyester fabric having a basis weight of 30 g / m ² .
A polyethylene terephthalate (PET) film (thickness 20 μm) was prepared as a non-permeable skin material.
As the rigid thermoplastic sheet, a hard felt made of polyester felt (thickness 3 mm, basis weight 1,100 g / m ² ) mixed with 30% by weight of heat-fusible fiber (melting point: 150 ° C. or less) was prepared.

  In the order shown in FIG. 1, the electromagnetic shielding material (2), the PET film (3), and the hard felt (4) are laminated, and a polyamide-based hot melt nonwoven fabric is sandwiched between the materials to bond the materials. . The laminated sheet is fixed so as not to be displaced, held on a hot plate at 200 ° C. for 5 minutes, immediately sandwiched between molds and pressed until it is sufficiently cooled, and is a flat plate of 150 × 150 mm and 3 mm thick A laminated sheet was produced.

(Example 2)
The same electromagnetic shielding material and non-permeable skin material as in Example 1 were used. As the rigid thermoplastic sheet, a sheet in which a protective layer was formed on one side of the hard felt used in Example 1 by applying chip resistance coating was used.

  In the order shown in FIG. 2, an electromagnetic shielding material (2), a PET film (3), and a hard felt (4) provided with a protective layer (5) are laminated, and an acrylic adhesive is used to bond the materials. This was applied and a flat laminated sheet was produced in the same manner as in Example 1.

(Comparative Example 1)
A laminated sheet was obtained in the same manner as in Example 1 except that no PET film was used.

(Comparative Example 2)
A laminated sheet was obtained in the same manner as in Example 1 except that low-weight polyester felt (weight per unit area 750 g / m ² ) was used as the rigid thermoplastic sheet.

(Comparative Example 3)
A laminated sheet was obtained in the same manner as in Example 1 except that a polypropylene resin plate having a thickness of 1 mm was used as the rigid thermoplastic sheet.

  About the lamination sheet obtained by the Example and the comparative example, evaluation by the following test methods was implemented.

[Electromagnetic shielding]
Based on the KEC method, the shielding effect (dB) at 10 MHz of each laminated sheet was measured. The measurement was performed at the initial stage of production of the laminated sheet and immediately after the aging test (50 ° C. 95% RH × 1 week) was completed.
Evaluation was based on the ratio of the shield effect after the aging test to the initial shield effect.
The shielding effect was calculated by the following formula (1).
SE = 20 × log10E ₀ / E _x (1)
SE: Shielding effect (dB)
E ₀ : Electric field strength in the space when there is no shield material E _x : Electric field strength in the space when there is a shield material

[Sound absorption]
It evaluated using the test piece after electromagnetic wave shielding evaluation.
Using an automatic normal incidence sound absorption coefficient measuring device (manufactured by Sotec Co., Ltd.), the normal incidence sound absorption coefficient at 500 Hz to 5 kHz was measured according to JIS A-1405 “Method for measuring normal incident sound absorption coefficient of building material in pipe method”. The laminated sheet was attached so that the protective layer was on the sound source side. The case where there was a sound absorption effect was evaluated as ◯, and the case where there was no sound absorption was evaluated as ×.

[Molded product strength]
Based on JIS K7074-1988 (the bending test method of carbon fiber reinforced plastic), the bending strength when the laminated sheet was bent by 10 mm was measured. It evaluated as (circle) with bending strength 20N or more.

[Shape retention]
The test piece cut out from the sample formed with the laminated sheet was placed in a sunshine weather meter manufactured by Suga Test Instruments Co., Ltd., and aged for 400 hours under a black panel at 63 ° C. and a water spray of 2 hours for 18 minutes.
The case where the test piece was holding the shape was evaluated as ◯, and the case where the test piece was not held was evaluated as x.

[Chip resistance]
A test piece cut from the laminated sheet was placed on a table so that the protective layer surface was on the upper side and the PET film surface was on the lower side, and a performance test was conducted by a nut dropping method by repeating 3 kg of brass nuts for a total of 150 kg.
The case where the surface of the test piece on which the brass nut was dropped was not torn was evaluated as ○, and the case where it was torn was evaluated as ×.

  The evaluation results are summarized in Table 1.

From Table 1, the laminated sheet of this invention showed the favorable result in electromagnetic wave shielding property, sound absorption property, shape maintenance property, form retainability, and chip resistance.
On the other hand, the laminated sheet of Comparative Example 1 in which the non-permeable skin material was not laminated had poor electromagnetic shielding properties after the aging test.
The laminated sheet of Comparative Example 2 in which a low-weight polyester non-woven fabric was laminated as a rigid material was inferior in shape maintenance, shape retention, and chip resistance.
The laminated sheet of Comparative Example 3 in which a polypropylene resin plate was laminated as a rigid material was inferior in lightness and sound absorption.

  The laminated sheet and molded product of the present invention are particularly useful for automobile under panels and the like.

DESCRIPTION OF SYMBOLS 1 Laminated sheet 2 Electromagnetic wave shielding material 3 Water-impermeable skin material 4 Rigid thermoplastic sheet 5 Protective layer

Claims (7)

  An electromagnetic shielding material in which a highly conductive metal is coated on one side or both sides of a sheet-like fiber material, a non-permeable skin material is laminated on one side, and a rigid thermoplastic sheet is laminated on the other side. Is a laminated sheet characterized by being bonded together.   The laminated sheet according to claim 1, wherein the rigid thermoplastic sheet has a protective layer on the surface opposite to the laminated surface with the electromagnetic wave shielding material.   The laminated sheet according to claim 1 or 2, wherein the rigid thermoplastic sheet has a three-point bending strength (deflection length of 10 mm) of 5 N or more. The rigid thermoplastic sheet is a felt mixed with 5 to 50% by weight of a heat-fusible fiber, and the basis weight thereof is in the range of 800 to 2,000 g / m ² . Laminated sheet.   A molded article formed using the laminated sheet according to claim 1.   An under panel for an automobile, wherein the laminated sheet according to any one of claims 2 to 4 is formed so that the protective layer faces the outside of the vehicle body.   A laminated sheet in which a non-permeable skin material is laminated on one side and a rigid thermoplastic sheet is laminated on the other side of an electromagnetic shielding material in which a highly conductive metal is coated on one or both sides of a sheet-like fiber material. A laminated sheet and a method for producing a molded product, wherein the skin material, the electromagnetic wave shielding material, and the rigid thermoplastic sheet are integrally formed by heating and compressing the material.

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