JP2015063019A - Thermoplastic laminate sheet and production method of the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thermoplastic laminate sheet and a production method of the sheet which is free from interlayer peeling, lightweight and inexpensive in a molding cost, and which has high physical strength against bending.SOLUTION: A thermoplastic laminate sheet (6) includes fabric layers (3a, 3b) bonded with adhesive layers (2a, 2b) to either surface of an inner layer (1), in which the inner layer (1) comprises a polypropylene sheet or an olefin sheet containing propylene; the fabric layers (3a, 3b) are made of a carbon fiber fabric; the adhesive layers (2a, 2b) are heat-fusible polyolefin films; and the laminate sheet is thermoplastic. The thermoplastic laminate sheet is obtained by disposing the inner layer, adhesive films on either surface of the inner layer, and carbon fiber fabric layers on either surface of the adhesive films, heating and pressurizing these films, and then cooling.

Description

  The present invention relates to a thermoplastic laminated sheet in which carbon fabric layers are integrated on both surfaces of an inner layer (core layer) and a method for producing the same.

  Conventionally, a laminate in which a plurality of reinforcing fiber fabrics such as carbon fibers and aramid fibers are laminated or integrated with a foam sheet is known. Patent Document 1 proposes a laminated sheet in which a carbon fiber fabric layer is integrated on the surface of an inner layer (core layer) sheet made of a foam. Patent Document 2 proposes that an epoxy resin is applied as a sizing agent on the carbon fiber surface to increase the adhesive strength with the thermosetting resin. Further, Patent Document 3 proposes that a thermoplastic resin layer is laminated on one side of carbon fiber and a thermosetting resin and vacuum-molded.

JP 2012-096482 A JP 2013-116998 A JP 2009-184239 A

  However, the conventional laminate has a problem that a thermosetting resin is laminated on carbon fibers, and a curing time is required for thermosetting at the time of molding, which requires a long molding time and a high molding cost.

  In order to solve the above-described conventional problems, the present invention provides a thermoplastic laminated sheet that does not have delamination, is lightweight, has high physical strength against bending, and has a low molding cost, and a method for producing the same.

  The thermoplastic laminated sheet of the present invention is a laminated sheet in which a fabric layer is bonded to both surfaces of the inner layer via an adhesive layer, the inner layer being a polypropylene sheet or an olefin-based sheet containing propylene, and the fabric layer is It is a carbon fiber woven fabric, the adhesive layer is a heat-sealable polyolefin film, and the laminated sheet is thermoplastic.

  The method for producing a thermoplastic laminated sheet of the present invention is a method for producing the above laminated sheet, wherein an inner layer, an adhesive film on both surfaces thereof, and a carbon fiber fabric layer on both surfaces are heated and pressurized. And then cooling.

  In the present invention, since the inner layer and the adhesive layer constituting the laminated sheet are olefin-based resins, a thermoplastic laminated sheet that reduces the molding cost, has no delamination, is lightweight, and has high physical strength against bending. Can be provided. Moreover, this laminated sheet is thermoplastic, and is suitable for vacuum forming, press forming, bending forming using thermal deformation, and the like, and can be an inexpensive formed body. The production method of the present invention can produce the laminated sheet of the present invention efficiently and rationally.

FIG. 1 is a schematic cross-sectional view of a laminated sheet according to an embodiment of the present invention. FIG. 2 is a schematic cross-sectional view of a laminated sheet according to another embodiment of the present invention. FIG. 3 is a schematic cross-sectional view showing an apparatus for producing a laminated sheet in one embodiment of the present invention. FIG. 4 is a schematic perspective view of a molded body obtained by vacuum forming the laminated sheet of one embodiment of the present invention.

  The laminated sheet of the present invention is a laminated sheet in which a carbon fiber fabric layer is bonded to both surfaces of an inner layer (core layer) via an adhesive layer. The inner layer (core layer) is a polypropylene sheet or an olefin-based sheet containing propylene. The inner layer (core layer) sheet may be a film. A polypropylene sheet or a sheet containing polypropylene has an advantage of practically satisfying physical properties and has an advantage of low cost. Furthermore, by using a heat-sealable polyolefin film as the adhesive layer, the inner layer (core layer) and the carbon fiber woven layer can be heated and pressurized and easily laminated and integrated.

  The inner layer (core layer) is preferably a non-foamed polypropylene sheet. The non-expanded polypropylene sheet does not crush the inner layer (core layer) even by press molding, and can be easily formed by vacuum forming, bending processing using thermal deformation, or the like.

  The inner layer (core layer) is preferably a propylene-ethylene random copolymer (RPP). RPP is a random copolymer containing more than 50 mol% propylene units and less than 50 mol% ethylene units, and has a melting point of 135 to 150 ° C. and is generally commercially available. RPP has an advantage of excellent heat-fusibility. The preferred thickness of the inner layer (core layer) is 0.1 to 2 mm, more preferably 0.2 to 1.5 mm.

  The heat-sealable polyolefin film is preferably low density polyethylene (LLDPE). LLDPE is excellent in heat processability, adhesiveness and transparency.

The carbon fiber woven fabric may be a woven fabric having any structure such as plain weave, twill weave (oblique fabric), satin weave, and other changed weaves. The weight (unit weight) per unit area of the carbon fiber fabric is preferably in the range of 50 to 500 g / m ² .

  The laminated sheet of the present invention may further include a polypropylene resin layer on any one surface layer of the carbon fiber woven fabric layer via an adhesive layer. If it does in this way, it can be set as the sheet | seat of the plate-shaped body covered with the polypropylene-type resin layer, and the application range as a molded object becomes wide.

Furthermore, the laminated sheet of this invention can also add a polyaxial fiber sheet between an inner layer (core layer) and a carbon fiber fabric layer. An example of the multiaxial fiber sheet is “Kuramas” manufactured by Kurashiki Boseki Co., Ltd. As an example, the direction of the multiaxial fiber is 0 ° / + 60 ° / −60 °, the weight per square meter (weight per unit area) is 350 g / m ² , and many PP filaments with a total fineness of 1850 deci tex are used as stitch yarn. There is a multiaxial fiber sheet using polyethylene terephthalate yarn.

  In the method for producing a laminated sheet of the present invention, an inner layer, an adhesive film on both surfaces thereof, and a carbon fiber fabric layer on both surfaces are heated and pressurized, and then cooled. As an example, an inner layer, an adhesive film on both surfaces thereof, and a carbon fiber woven fabric layer on both surfaces thereof are continuously hot pressed, continuously cooled, and a laminated sheet is continuously manufactured. The atmospheric temperature in the hot pressing step is preferably 150 to 190 ° C, more preferably 160 to 180 ° C. The applied pressure is preferably about 1 MPa. The heating time is preferably 0.5 to 5 minutes, more preferably 1 to 4 minutes. The time for the cooling step is preferably 0.5 to 5 minutes, and more preferably 1 to 4 minutes. The cooling temperature is preferably up to about 30 ° C. or less. The thickness of the entire laminated sheet after molding is preferably 0.5 to 5 mm. A continuous process is preferred for mass production.

  The production method of the present invention is not limited to the continuous method, and can be produced by a heating and pressing press and a cooling method for each time. This method is sufficient when producing samples or manufacturing on a small scale. The manufacturing conditions of this method are the same as in the continuous method.

  Next, it demonstrates using drawing. In the following drawings, the same reference numerals indicate the same parts. FIG. 1 is a schematic cross-sectional view of a laminated sheet according to an embodiment of the present invention. In this laminated sheet 6, carbon fiber fabric layers 3a and 3b are bonded to and integrated with both surfaces of the inner layer 1 via adhesive layers 2a and 2B.

  FIG. 2 is a schematic cross-sectional view of a laminated sheet according to another embodiment of the present invention. This laminated sheet 7 has carbon fiber fabric layers 3a and 3b on both surfaces of the inner layer 1 via adhesive layers 2a and 2B, and further polypropylene resin layers (skin layers) 5a and 5b via adhesive layers 4a and 4b. Stacked and integrated. The skin layer may be transparent and may have a woven pattern appearance of an internal carbon fiber fabric. In addition, various patterns can be printed or colored on the skin layer.

  FIG. 3 is a schematic cross-sectional view showing a laminated sheet manufacturing apparatus 10 in one embodiment of the present invention. The laminated sheet manufacturing apparatus 10 includes raw material sheet supply rolls 14, 15 a, 15 b, 16 a, 16 b, a heating / pressurizing region 20, and a cooling region 21, and the whole moves continuously. First, the inner layer (core) is supplied from the supply rolls 14a and 14b, the adhesive film is supplied from the supply rolls 15a and 15b, and the carbon fiber fabric is supplied from the supply rolls 16a and 16b to the pressure rolls 17a and 17b. Metal plates 18 and 19 are incorporated in the pressure rolls 17a and 17b and 22a and 22b in an endless manner. Next, the cooling air is cooled by supplying cooling air from the arrow a and discharging from the arrow b. In the case of efficient cooling, a water cooling pipe is disposed in the cooling region 21 in addition to the cooling air. The laminated sheet 23 taken out from the pressure rolls 22a and 22b is cut into a predetermined length.

  FIG. 4 is a schematic perspective view of a molded body obtained by vacuum forming the laminated sheet of one embodiment of the present invention. This is an example of a molded body having a maximum horizontal length of 260 mm, a maximum depth of 170 mm, and a height of 500 mm. This laminated sheet has the advantage that it can be deep drawn. Furthermore, this laminated sheet is thermoplastic, and in vacuum forming, press forming, bending forming utilizing thermal deformation, etc., the forming cycle is short and the processing cost is low.

  Hereinafter, the present invention will be described more specifically with reference to examples. The present invention is not limited to the following examples.

<Measurement method of bending elastic modulus and bending stress>
It measured by the 3 point | piece bending test based on JISK7171. The test piece size was 20 mm wide, 50 mm long, and the test speed was 1 mm / min. The shape of the holding jig was R5, the shape of the fulcrum was R2, and the fulcrum interval was 24 mm.

Example 1
<Inner layer (core layer)>
As the inner layer (core layer), a commercially available random type polypropylene (RPP) sheet, a melting point of 145 ° C., a thickness of 500 μm, and a weight per unit area of 450 g / m ² was used.
<Carbon fiber fabric>
A plain woven fabric was used as the carbon fiber woven layer, and a weight (unit weight) per unit area of 65 g / m ² was used.
<Adhesive film>
Commercially available low density polyethylene (LLDPE), melting point 110 ° C., thickness 30 μm, weight per unit area 27 g / m ² was used.
<Creation of laminated sheet>
An adhesive film and a carbon fiber woven fabric were laminated in this order on both surfaces of the inner layer (core layer), press-molded at a temperature of 170 ° C., a pressure of 1 Mpa for 1 minute, and then cooled to room temperature (27 ° C.). As a result, the adhesive film was welded to integrate the whole to obtain a laminated sheet. A schematic cross-sectional view of this laminated sheet is as shown in FIG.

  Table 1 shows the bending elastic modulus and bending stress of the obtained laminated sheet.

(Example 2)
The same procedure as in Example 1 was performed except that a plain woven fabric was used as the carbon fiber woven layer, and the weight per unit area (weight per unit area) was 130 g / m ² . The physical properties of the obtained laminated sheet are summarized in Table 1.

(Example 3)
The adhesive film described in Example 1 is placed on the outer side of the carbon fiber fabric layer in Example 1, and a homopolymer type polypropylene (HPP, melting point 160 ° C.): 25 wt% and a random type polypropylene (RPP, melting point) as a skin layer thereon. 145 ° C.): The same procedure as in Example 1 was conducted except that a thickness of 200 μm blended with 75 wt% and a weight of 180 g / m ² per unit area were laminated. A schematic cross-sectional view of this laminated sheet is as shown in FIG. The physical properties of the obtained laminated sheet are summarized in Table 1.

(Comparative Example 1)
Table 1 summarizes the physical properties of the inner layer (core layer) of Example 1 as Comparative Example 1. In addition, the data of the bending elastic modulus and bending stress of each example are data of MD (length direction).

  As apparent from Table 1, the product of the example of the present invention was a laminated sheet having high bending elastic modulus and bending stress, no delamination, light weight, and high physical strength against bending. Further, this laminated sheet was thermoplastic, suitable for vacuum forming, press forming, bending forming utilizing thermal deformation, and the like, and was an inexpensive formed body. Furthermore, since the carbon fiber woven layer is bonded to the inner layer through a heat-sealable polyolefin film, a beautiful woven pattern of the woven fabric can be formed as it is on the surface of the laminated sheet.

  Molded articles using the laminated sheet of the present invention are automobile parts, automobile interior parts, home appliances, medical protective equipment, suitcases, containers, shelves, pallets, panels, bags, sleeve boxes for automatic warehouses, doors, rolls. It can be applied to consumer laminated products such as long boxes, tatami core materials, exhibition booth-like wall materials, T-boards (truck backing plates), and simple table sets.

1 Inner layer (core layer)
2a, 2b Adhesive layers 3a, 3b Carbon fiber fabric layers 4a, 4b Adhesive layers 5a, 5b Skin layers 6, 7, 23 Laminated sheet 10 Laminated sheet manufacturing apparatus 14a, 14b, 15a, 15b, 16a, 16b Supply rolls 17a, 17b , 22a, 22b Pressure rolls 18, 19 Metal plate 20 Heating and pressing area 21 Cooling area

Claims (6)

A laminated sheet in which a fabric layer is bonded to both surfaces of the inner layer via an adhesive layer,
The inner layer is a polypropylene sheet or an olefin-based sheet containing propylene,
The fabric layer is a carbon fiber fabric;
The adhesive layer is a heat-sealable polyolefin film,
The thermoplastic laminated sheet, wherein the laminated sheet is thermoplastic.   The thermoplastic laminated sheet according to claim 1, wherein the inner layer is a non-foamed polypropylene sheet.   The thermoplastic laminated sheet according to claim 1 or 2, wherein the inner layer is a propylene-ethylene random copolymer.   The thermoplastic laminated sheet according to any one of claims 1 to 3, wherein the heat-sealable polyolefin film is low-density polyethylene.   The thermoplastic laminated sheet according to any one of claims 1 to 4, further comprising a polypropylene-based resin layer on one surface layer of the fabric layer via an adhesive layer. A method for producing a thermoplastic laminated sheet according to any one of claims 1 to 5,
A method for producing a thermoplastic laminated sheet, comprising: an inner layer; an adhesive film on both surfaces thereof; and a carbon fiber woven fabric layer on both surfaces, heating and pressing, and then cooling.

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