JP5547412B2 - Planar composite - Google Patents

Description

  The present invention relates to a planar composite useful as a prepreg excellent in drapability, and a method for producing the same.

  In recent years, composite materials using carbon fibers, glass fibers, aramid fibers, and the like as reinforcing fibers have been widely used as structural materials for aircraft and the like by utilizing their high specific strength and specific rigidity. These composite materials are often molded from a prepreg, which is an intermediate product in which a reinforcing fiber is impregnated with a matrix resin, through molding / processing steps such as heating, pressing, and shaping.

  Most of the conventional prepregs are made by completely impregnating reinforcing fibers into a matrix resin. When these fully impregnated prepregs are molded, there is a problem that air is trapped between the layers during molding and voids are generated in the molded product, resulting in deterioration of physical properties, and it is necessary to perform molding at a high pressure.

  Therefore, in recent years, partially impregnated prepregs in which reinforcing fibers are partially impregnated with a matrix resin have been proposed, and voids are formed at a lower pressure than conventional prepregs by making the reinforcing fibers in the non-impregnated parts into air deaeration paths at the time of molding. Techniques for obtaining a small number of molded products have been used.

  As the partially impregnated prepregs proposed, for example, a reinforcing fiber layer (F) and a matrix resin layer (M) consisting of two layers (type F / M), a reinforcing fiber layer (F) ) Consists of three layers (type M / F / M), one layer and two matrix resin layers (M), and one reinforcing fiber layer (F) consists of two layers and one matrix resin layer (M). There are three layers (type F / M / F).

  Patent Document 1 describes type F / M and type M / F / M mainly regarding thermosetting resin compositions such as epoxy resins, and Patent Document 2 describes type F / M and type type F / M /. F is described, and Patent Document 3 proposes a partially impregnated prepreg in which a ventilation path is provided in the thickness direction of the prepreg.

However, in these methods, since the impregnation depth of the reinforcing fiber layer into the matrix resin layer is uniform in the width direction of the prepreg, the partially impregnated prepreg is a rigid sheet when the matrix resin layer is a thermoplastic resin. However, the drapability is poor and it is difficult to apply to complicated shapes. When the unimpregnated portion is increased in order to impart drape properties, the reinforcing fiber layer and the matrix resin layer are easily separated, and there is a problem that fluffing at the time of cutting increases and handling is impossible.
On the other hand, Patent Document 4 has a description of a reinforced fiber-containing resin molded article having excellent adhesion performance by having one or a plurality of surfaces on which the concave and convex portions are formed.

JP-T-2001-511827 International Publication No. 00/27632 Pamphlet JP 2002-249605 A Japanese Patent Laid-Open No. 10-296866

  An object of the present invention is to provide a prepreg having excellent drapeability that can be applied to shapes that cannot be shaped by conventional thermoplastic resin prepregs.

The present invention relates to a thermoplastic resin layer having regular irregularities with a width of 0.1 mm to 100 mm and a height of 0.1 mm to 3 mm on the surface, and a fiber layer comprising fibers having a specific modulus of 20 GPa / g / cm ³ or more. The planar composite is characterized in that the fiber layer is partially impregnated with a thermoplastic resin.

  By using the planar composite of the present invention, it becomes possible to form a free shape that could not be shaped by a conventional thermoplastic resin prepreg.

The schematic diagram of the cross section of a planar composite. The schematic diagram of an example of the uneven | corrugated shape of a planar composite. 3 is an embossed shape photograph of the planar composite of Example 1. FIG. 2 is a cross-sectional photograph of a cut surface of the planar composite of Example 1. FIG.

The present invention relates to a thermoplastic resin layer having regular irregularities with a width of 0.1 mm to 100 mm and a height of 0.1 mm to 3 mm on the surface, and a fiber layer comprising fibers having a specific modulus of 20 GPa / g / cm ³ or more. The planar composite is characterized in that the fiber layer is partially impregnated with a thermoplastic resin. Here, the partial impregnation is a state in which the thermoplastic resin is partially impregnated in the fiber layer, that is, not completely impregnated in the thickness direction of the fiber layer, about 0.1 to 50% of the fiber layer thickness, preferably 0.8. About 5 to 10% of the resin is impregnated with the thermoplastic resin. The planar composite of the present invention can be used as a prepreg that can be molded into a free shape by partially impregnating a fiber layer with a thermoplastic resin.
Having the irregularities on the surface of the thermoplastic resin layer means that the two surfaces of the thermoplastic resin layer have irregularities on the surface different from the fiber layer side, that is, on the outer surface.

  The uneven structure of the planar composite of the present invention is a regular structure having a width of 0.1 mm to 100 mm and a height of 0.1 mm to 3.0 mm, but the width is 0.5 mm to 1.5 mm and the height is 0. 0.5 mm to 2.0 mm is preferable. When the width of the unevenness is smaller than 0.1 mm, the boundary between the convex portion and the concave portion becomes ambiguous and the drape property is lost. When the width is larger than 100 mm, the resin-impregnated portion of the concave portion becomes wide and the drape property is lost. If the height is 0.1 mm or less, the effect of the drapeability according to the present invention is small, and if the height is 3.0 mm or more, the planar composite becomes bulky and the drape property is lost. As shown in FIG. 1, the width in the concavo-convex structure is the width of the convex portion, and the height is the height of the convex portion.

The fiber constituting the fiber layer of the planar composite of the present invention has a specific modulus of 20 GPa / g / cm ³ or more, and specific examples include carbon fiber, glass fiber, and aramid fiber. In particular, the specific elastic modulus is preferably 100 GPa / g / cm ³ or more. Specific examples of fibers having a specific elastic modulus of 100 GPa / g / cm ³ or more include aramid fibers and carbon fibers. The specific elastic modulus is a value obtained by dividing the elastic modulus (GPa) in the fiber axis direction by the density (g / cm ³ ).

  The kind of the thermoplastic resin constituting the planar composite of the present invention is not particularly limited, and specifically, polyolefin such as polypropylene, polyamide such as polyvinyl chloride and nylon, polycarbonate, polyethylene terephthalate, polyethylene naphthalate or polybutylene. Polyester such as terephthalate, polylactic acid, polyacetal, polyoxymethylene, polyphenylene sulfide, poly (styrene-acrylonitrile-butadiene) copolymer (ABS resin), poly (acrylonitrile-styrene) copolymer (AS resin) or high Examples thereof include styrene resins such as impact polystyrene (HIPS) and acrylic resins such as polymethyl methacrylate.

The planar composite of the present invention obtains a laminate of a fiber layer composed of fibers having a specific modulus of elasticity of 20 GPa / g / cm ³ or more and a thermoplastic resin layer, and further performs uneven treatment on the surface of the thermoplastic resin layer. Preferably obtained.

  A schematic cross-sectional view of the planar composite of the present invention is shown in FIG. The fiber layer is impregnated with the thermoplastic resin by the uneven treatment. As for the state of impregnation in the fiber layer, the cross-section of the planar composite can be observed with a microscope at 50 to 500 times, whereby the resin impregnation depth d1 into the fiber layer at the concave portion and the resin impregnation at the convex portion The depth d2 can be determined.

  The form of the resin of the thermoplastic resin layer is not particularly limited as long as it can be processed by using an embossing roller or the like. Specifically, a nonwoven fabric, a sheet, a film, a powder, or a method of casting a molten resin is mentioned. However, the nonwoven fabric is particularly preferred from the viewpoint of handling and drapeability. The non-woven fabric is produced by, for example, a melt-blowing method, and a plurality of single fibers made of resin are entangled or bonded.

  The convex portions of the planar composite of the present invention are preferably continuously formed in a uniaxial direction in a straight line or a curved line. Furthermore, it is preferable that the convex portions are continuously formed in a linear or curved shape in the multiaxial direction. A schematic diagram of a specific shape is illustrated in FIG. 2, and the convex part is continuously formed in a straight line or a curved line in a uniaxial direction. Preferably it is. Specifically, a striped shape, a lattice shape, or an oblique lattice shape can be mentioned. The shape of the irregularities is not particularly limited, and may be round, square, or honeycomb.

  Although there is no limitation in particular as a form of the fiber layer in the present invention, it is one direction which consists of a set of reinforcing fiber bundles arranged in parallel, plain fabric, twill fabric, satin fabric using fiber bundles as warp and / or weft Examples include woven fabrics, bi-directional woven fabrics, and multiaxial woven fabrics. Alternatively, it may be a nonwoven fabric made of reinforcing fibers, mat, knit, braid or the like. Multiaxial woven fabric is a bundle of fiber reinforcements aligned in one direction, laminated at different angles, and stitched yarns such as nylon yarn, polyester yarn, and glass fiber yarn. It refers to a woven fabric that penetrates in the direction and stitches by reciprocating along the surface direction between the front and back surfaces of the laminate. The thickness of the fiber layer is preferably 0.1 mm to 0.5 mm, and the fiber diameter constituting the fiber layer is preferably 5 μm to 30 μm.

As a preferred method for producing the planar composite of the present invention, as described above, a laminate of a fiber layer composed of fibers having a specific elastic modulus of 20 GPa / g / cm ³ or more and a thermoplastic resin layer is obtained, and further, The surface of the plastic resin layer is subjected to uneven processing. Specifically, there may be mentioned a method in which a thermoplastic resin layer is continuously supplied to one side of the fiber layer in a nonwoven fabric, sheet, film, powder, or molten state and subjected to uneven treatment such as embossing. Especially, it is preferable to supply a thermoplastic resin layer with a nonwoven fabric form. As a method of providing the thermoplastic resin layer on one side of the fiber layer, a method of continuously supplying the nonwoven fabric by a melt blow method is preferable.

  As the calender roller temperature in embossing, in the case of a crystalline thermoplastic resin, the matrix resin side is not lower than the glass transition temperature (Tg: ° C.) and not higher than the melting point (Tm: ° C.), and the fiber layer side is the melting point (Tm: ° C.). As described above, the melting point (Tm: ° C.) is within + 50 ° C. In the case of an amorphous thermoplastic resin, the matrix resin side is set to the glass transition temperature (Tg: ° C.) or higher and the melting temperature or lower, and the fiber layer side is set to the melting temperature or higher. It is preferable.

  Since the planar composite of the present invention is used as a partially impregnated prepreg and has sufficient drapability, it can be applied to shapes that could not be shaped by conventional thermoplastic resin prepregs.

  Examples are shown below, but the present invention is not limited thereto.

[Example 1]
A polypropylene resin (J709QG manufactured by Prime Polymer Co., Ltd.) having a basis weight of 125 g / m ² is applied to the upper surface of a twill weave W3161 (CF weight 200 g / m ² ) having a width of 1000 mm using carbon fiber HTA-3K (manufactured by Toho Tenax Co., Ltd.). The nonwoven fabric-side embossing roller is heated to 140 ° C., the fiber-side embossing roller is heated to 160 ° C., the linear pressure is 3 MPa, and the line speed is 1 m / min. The planar composite was obtained by impregnating at 0.8% with the convex part and 8% with the concave part with respect to the fiber layer thickness of 250 μm.
FIG. 3 shows a photomicrograph at 50 times the surface of the resin layer of the obtained planar composite. The width of the unevenness was 1 mm and the height was 0.4 mm. The obtained planar composite could be shaped without causing cracks even on a mold surface having a right angle of 90 °, and had sufficient drape.
The planar composite was cut out with a width of 1 cm and a length of 5 cm, and the cut surface was observed 100 times (FIG. 4). It was confirmed that the fiber layer was partially impregnated with the resin at each of the concave and convex portions of the planar composite.
The resin impregnation depth d1 into the fiber layer in the concave portion of the planar composite obtained was 2 μm, the resin impregnation depth d2 in the convex portion was 20 μm, and d2 / d1 was 0.1.

[Example 2]
A polypropylene resin (BC06C, MG05ES, manufactured by Nippon Polypro Co., Ltd.) is applied to the upper surface of a plain woven fabric W3101 (CF weight per unit area: 200 g / m ² ) having a width of 1000 mm using carbon fiber HTA-3K (manufactured by Toho Tenax). ² , the heating temperature of the embossing roller on the nonwoven fabric side is 140 ° C., the heating temperature of the embossing roller on the fiber side is 160 ° C., the linear pressure is 3 MPa, and the line speed is 1 m / min. The sheet composite was obtained by impregnating with a pressure of 1.0% at the convex part and 6% at the concave part with respect to the fiber layer thickness of 250 μm.
The obtained planar composite could be shaped without causing cracks even on a mold surface having a right angle of 90 °, and had sufficient drape. The width of the unevenness was 1 mm and the height was 0.4 mm.

[Example 3]
A polypropylene resin (J709QG manufactured by Prime Polymer Co., Ltd.) having a basis weight of 250 g / m ² is formed on the upper surface of a twill woven fabric W3161 (CF weight 200 g / m ² ) having a width of 1000 mm using carbon fiber HTA-3K (manufactured by Toho Tenax Co., Ltd.). The nonwoven fabric-side embossing roller is heated to 140 ° C., the fiber-side embossing roller is heated to 160 ° C., the linear pressure is 3 MPa, and the line speed is 1 m / min. And a surface composite was obtained. A planar composite body in which 0.9% of the convex portions and 10% of the concave portions were impregnated with respect to the fiber layer thickness of 250 μm was obtained.
The obtained planar composite could be shaped without causing cracks even on a mold surface having a right angle of 90 °, and had sufficient drape. The width of the unevenness was 1 mm and the height was 0.4 mm.

1 thermoplastic resin layer 2 fiber layer 3 uneven width 4 uneven height 5 recessed

Claims (7)

It is composed of a thermoplastic resin layer having regular irregularities with a width of 0.1 mm to 100 mm and a height of 0.1 mm to 3 mm on the surface, and a fiber layer made of fibers having a specific elastic modulus of 20 GPa / g / cm ³ or more. A planar composite comprising a fiber layer partially impregnated with a thermoplastic resin. 2. A planar composite according to claim 1 , wherein the fiber layer is partially impregnated with a thermoplastic resin by an uneven treatment .   The planar shape according to claim 1 or 2, wherein a resin impregnation depth d1 into the fiber layer in the concave portion of the planar composite and a resin impregnation depth d2 into the fiber layer in the convex portion are d2 / d1 <0.5. Complex.   The planar composite according to any one of claims 1 to 3, wherein the convex portions are continuously formed in a uniaxial direction in a straight line or a curved line.   The planar composite according to any one of claims 1 to 3, wherein the convex portions are continuously formed in a linear or curved shape in a multiaxial direction.   The planar composite according to any one of claims 1 to 5, wherein the fiber layer is a woven fabric composed of continuous fibers.   A prepreg comprising the planar composite according to any one of claims 1 to 6.