JPS6395915A - Manufacture of composite material - Google Patents

Abstract

PURPOSE:To produce the composite material in which reinforcing fibers are uniformly orientated by heating and pressurizing the fabric composed of the yarn made of thermoplastic resin and the yarn of reinforcing fiber at the melting temperature of said thermoplastic resin or higher. CONSTITUTION:Glass fiber rovings are used for warps, and polypropylene strip yarns are used for wefts, and thus the fabric mixing a plain cloth therewith is woven, using a manual weaving machine. The fabric is pressurized by a compression molding machine, after the fabric has been heated between hot plates, while fixing the direction of the longitudinal yarn of the fabric. After cooling, a composite material is obtained. Thus, the composite material in which the glass fibers are arranged equidistantly and finely in parallel may be abtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for manufacturing a fiber-reinforced resin composite (hereinafter simply referred to as composite) comprising a thermoplastic resin and reinforcing fibers. Specifically, the present invention provides a method for manufacturing a composite body in which a woven fabric in which the weft and warp yarns are composed of different thermoplastic resin fibers or reinforcing fibers is heated and pressurized to form the fabric.

[Prior art]

Conventionally, methods for producing composites include, for example, a method in which reinforcing fiber tow or woven fabric is impregnated with a thermosetting resin and cured, or a reinforcing fiber or its woven fabric is coated with resin powder, and then the resin is applied under pressure. Methods have been proposed in which powder is melted and impregnated into tissue. However, these methods have problems in handling, such as the prepreg intermediate being sticky and the resulting composite being difficult to process into a complex shape.

On the other hand, recently, a method has been proposed in which continuous fiber tow containing a mixture of spun thermoplastic polymer fibers and non-thermoplastic reinforcing fibers, particularly carbon fibers, is heated to a temperature higher than the melting point of the thermoplastic polymer fiber, which is a continuous fiber tow. JP-A-60-20903
No. 3, JP-A No. 60-209034), a method of laminating a woven fabric whose warp is made of non-carbon fibers and whose weft is made of carbon fiber with a thermosetting resin layer which is a constituent element of prepreg (JP-A No. 58-2003) No. 201824) etc. have been proposed.

[Problem to be solved by the invention]

However, the composite obtained by the above-proposed manufacturing method does not satisfy all the required functions, especially when the orientation of the reinforcing fibers is uniform (the fibers are aligned <) and the composite is not crimped ( There is a demand for excellent performance in processability, with no decrease in strength due to bending, and good wetting of reinforcing fibers with thermoplastic resin. Therefore, an object of the present invention is to provide a suitable manufacturing method for easily obtaining a composite material having the above-mentioned properties.

[Means to solve the problem]

As a result of intensive studies in view of the above-mentioned problems, the present inventors found that a fabric whose weft or warp is composed of different thermoplastic resin fibers or reinforcing fibers, respectively, is heated and pressurized at a specific hot water temperature to form the fabric. The inventors have discovered that by doing this, it is possible to easily obtain a composite with uniform orientation of the reinforcing fibers, no decrease in strength due to crimping, and no tackiness and excellent workability, leading to the proposal of the present invention. Ta. That is, according to the present invention, the weft (or warp) is made of thermoplastic resin fiber and the warp
Provided is a method for producing a composite, which is a woven fabric whose weft yarns are composed of reinforcing fibers, and is formed by heating and pressing at a temperature higher than the melting temperature of the thermoplastic resin and higher than the melting temperature of the reinforcing fibers. Ru. In particular, in the present invention, two or more of the above-mentioned fabrics are laminated, or a thermoplastic resin sheet is laminated on the fabric, and the fabric is heated and pressurized to form the fabric. A composite with good wetting is obtained.

Examples of the thermoplastic resin of the present invention include polypropylene, vinyl chloride resin, vinyl acetate resin, polystyrene, A
BS resin, acrylic resin, polyethylene, fluororesin,
Polyamide resin, polyester resin, acetal resin.

polycarbonate, polyetherimide, polyetherketone, polyetheretherketone, polysulfone,
polyether sulfone.

Known materials such as polyphenylene sulfide, liquid crystal polymers, and mixtures thereof are not particularly limited, but polyprobrene is generally used, and polyether ether ketone is preferably used for applications requiring particularly high strength.

The above-mentioned thermoplastic resins can be used as they are (unmodified), but it is particularly effective to use modified polyolefins obtained by grafting unsaturated carboxylic acids or unsaturated silane compounds onto polyolefins. In other words, a woven fabric made of such modified polyolefin fibers and glass fibers, or a composite obtained by heating and pressurizing and molding a laminate of the woven fabric and a sheet, has good adhesion between the polyolefin resin and the glass fibers. This is preferable because the strength is also increased. Such modified polyolefins can be obtained by conventionally known methods. That is, modified polyolefins grafted with unsaturated carboxylic acids can be prepared by combining unsaturated carboxylic acid monomers such as acrylic acid, maleic acid, itaconic acid, maleic anhydride, and itaconic anhydride with a radical generator such as an organic peroxide. It can be obtained by grafting onto a polyolefin by a known method such as a solution state, melt state or slurry state in the presence of the polyolefin.

In addition, modified polyolefins grafted with unsaturated silane compounds can be produced by combining polyolefins with monomers of unsaturated silane compounds such as vinyltrimethoxysilane, vinyltriethoxysilane, and γ-methacryloyloxypropyltrimethoxysilane using organic peroxides. It can be produced by a method of reacting in a molten state in the presence of such a radical generator.

Incidentally, these modified polyolefins can also be used in combination with unmodified polyolefins. In addition, it is generally appropriate to place the graft-reacted unsaturated carboxylic acids or unsaturated silane compounds in an amount of 0.01 to 1 percent by grafting based on the total resin.

The thermoplastic resin fibers used in the present invention include stretched or unstretched fibers, filaments, monofilaments, yarns, tapes, etc. made of the above-mentioned thermoplastic resins,
Stables, ribbons, and combining them,
This is a general term that also includes those bound with sizing agents. The method for producing such thermoplastic resin fibers is not particularly limited, and for example, a filament may be melted and extruded from a spinneret, cooled and solidified while being drafted, and then wound up, and then stretched as necessary.

The method includes a method of heat treatment, a method of stretching the film as necessary after molding, and a method of slitting or splitting the film. The thickness of the fibers obtained in this way is not particularly limited, but
Generally, a denier of 10 to 10,000 is suitable.

The thermoplastic resin sheet used in the present invention is obtained by extrusion molding, compression molding, injection molding, etc. of the thermoplastic resin as described above, and the thickness of the sheet is determined by the thickness of the fabric to be laminated and the composite material. Generally, a sheet with a thickness of 0.1 to 101 m is preferably used, although it varies depending on the final reinforcing fibers in the body.

The reinforcing fibers used in the present invention are reinforcing fibers having a melting temperature higher than the melting temperature of the thermoplastic resin used, such as glass fibers.

Examples include carbon fiber, aramid fiber, poron fiber, ceramic fiber, metal fiber 2 synthetic resin fiber, etc., but glass fiber is suitable when used in combination with the above-mentioned modified polyolefin, and especially for applications requiring high strength. Carbon fiber is preferred. Any form of fiber can be used, such as single yarn, roving, or yarn, and the thickness of the fiber is not particularly limited, but generally the diameter of the fiber is 10
~io,oo.

Denier ones are preferably used.

It is important that the woven fabric (general term including woven fabric) used in the present invention is one in which the above-mentioned thermoplastic resin fibers and reinforcing fibers are woven into a specific configuration. That is, weft (or warp)
is thermoplastic resin fiber and the warp (or weft) is composed of reinforcing fiber.If the weft (or warp) is made of thermoplastic resin fiber, reinforcing fiber, or a blend thereof, weaving is not possible. Sometimes the reinforcing fibers crimp together,
When heated and pressurized, the strength of the composite after molding may decrease, or the orientation of the fibers may be disturbed due to melting of the thermoplastic resin fibers in the fabric during heating and pressurizing molding, resulting in poor moldability and processability of the resulting composite. The intended purpose of the present invention, such as a decrease in

The mixing ratio of thermoplastic resin fibers and reinforcing fibers in the fabric described above depends on the use of the composite.

The deviation is determined as appropriate depending on whether thermoplastic resin sheets are laminated or not, and when thermoplastic resin sheets are laminated, the thickness of the thermoplastic resin sheets to be laminated. When thermoplastic resin sheets are not laminated, reinforcing fibers generally account for 5 to 70 vol 1% (701%) of the entire fabric, particularly 10 to 50 vol.
o1% is preferred. If the mixing (containing) wL of the reinforcing fibers is less than 5v01%, the reinforcing effect will be small, and if the mixing amount exceeds 70v1%, impregnation of the thermoplastic resin during hot-press molding will be insufficient. In addition, when laminating thermoplastic resin sheets, the amount of reinforcing fiber mixed is generally 5 to 95 vol% of the entire fabric, especially 30 to 90 vol.
O1% is preferred. If the mixing amount is less than 5 vol%, the reinforcing effect will be small, and if it exceeds 95 vol%, the effect of improving the wetting of the reinforcing fibers by the thermoplastic resin will be reduced.

Note that the coarseness of the weft or warp can be arbitrarily changed as necessary.

Weaving can be carried out using a known loom such as a hand loom or an automatic loom, and can be woven into a plain weave, twill weave, satin weave, or the like. Furthermore, when using an automatic loom, it is also preferable to adopt a room creel system.

Next, in the present invention, a good composite can be obtained by laminating the above-described woven fabric or, if necessary, a woven fabric and a thermoplastic resin sheet, and molding the woven fabric by heating and pressing.

When forming a woven fabric by heating and pressing, it is possible to form a single woven fabric or a laminated body of multiple woven fabrics, but in particular two or more woven fabrics may be laminated at any angle, preferably at right angles. It is preferred to increase the strength of the resulting composite. On the other hand, in the case of laminating a textile and a thermoplastic resin sheet and molding them by heating and pressing, the method of laminating the textile and the thermoplastic resin sheet is lamination of one sheet, sheet/fabric/sheet/fabric/sheet. When using a plurality of laminated fabrics and sheets, or two or more layers of fabrics, as in... Can be stacked at an angle of At this time, although different types of resins can be used as the thermoplastic resin for the sheet and the thermoplastic resin in the fabric, it is preferable to use the same type of resin. In addition, when the reinforcing fibers are glass fibers and a modified polyolefin grafted with a thermoplastic resin, an unsaturated carboxylic acid, or an unsaturated silane compound is used, the modified polyolefin must be used especially for the thermoplastic resin fibers constituting the fabric. is desirable, and the thermoplastic resin sheet may be either unmodified or modified polyolefin.

Heating in the present invention needs to be carried out at a temperature above the melting temperature of the thermoplastic resin and below the melting temperature of the reinforcing fibers,
A good composite of the present invention cannot be obtained outside this range. Further, as the pressure molding method, a known method such as a compression molding method using a compression molding machine or an extrusion lamination method can be used without particular limitation. In particular, when fabric and thermoplastic resin sheets are laminated and molded by heating and pressurizing, two T-die extruders are placed on both sides of the fabric heated above the melting temperature of the thermoplastic resin fibers. A preferred method is to laminate extruded molten thermoplastic resin sheets and press them using a nip ring. In addition, when molding by heating and pressurizing, it is preferable to fix the periphery of the fabric and apply tension in order to prevent shrinkage due to melting of the resin. It is possible to obtain a product with good alignment of the fibers, good appearance, and superior strength.

[Effect]

Generally, it is very difficult to uniformly align and fill reinforcing fibers into a thermoplastic resin. However, according to the present invention, a fabric in which the weft (or warp) is a thermoplastic resin fiber and the warp (or weft) is a reinforcing fiber, or a laminate of a fabric and a thermoplastic resin sheet is heated and pressurized. By molding, the thermoplastic resin fibers and thermoplastic resin sheet are melted while the reinforcing fibers are uniformly arranged, and a composite in which the reinforcing fibers are uniformly oriented can be easily produced. In addition, especially when two or more fabrics are laminated at any angle and molded by heating and pressing, the reinforcing fibers are not woven, so the reinforcing fibers in each direction are uniformly oriented, and
A composite with small crimp (bending) and excellent appearance and strength can be obtained. Note that the composite obtained by the present invention can also be molded into various shapes by hot stamping molding or the like.

〔Example〕

Examples of the present invention will be shown below, but the present invention is not limited to these examples.

In addition, the strength in the following results shows the results measured based on the following method.

i.e. width 2 cI in the longitudinal and transverse directions from the composite.
Cut out a test piece in the shape of IL + 15 cm, and use a tensile test material with a distance between chucks of 5α and a tensile speed of 10 m/
A tensile test was conducted under the conditions of Im, and the tensile strength in the longitudinal direction and the transverse direction was measured, and the average value of both was taken as the tensile strength unless otherwise specified.

Example 1 Using 4500 denier glass fiber roving for the warp and 4000 denier polypropylene split yarn for the weft, the fabric was woven on a hand loom to a thickness of about 1.2 tm and a basis weight of 110.
01/Ze, a plain weave mixed fiber with a glass fiber content of 30 vol. 1% was woven. This woven fabric was heated between hot plates at 200° C. for 10 minutes with the warp direction fixed, and then cooled under pressure using a compression molding machine to obtain a composite with a thickness of 0.7 nm.

The glass fibers in this composite were arranged neatly in parallel at equal intervals. The tensile strength of this composite in the glass fiber orientation direction was 1350V.

Example 2 Two sheets of the mixed fibers used in Example 1 were stacked orthogonally, the periphery was fixed, and molded under heat and pressure in the same manner as in Example 1 to obtain a composite with a thickness of 1.4 sots. . The glass fibers in this composite were uniformly arranged at equal intervals in the vertical and horizontal directions. The tensile strength of this composite was 1370%.

Comparative Example 1 A 4500 denier glass fiber roving was woven on a hand loom into a plain weave with a thickness of about 0.4 tx and a basis weight of 5201/pi. This glass fiber fabric was sandwiched between two polypropylene sheets with a thickness of 0.3 rugs, and heated at 200℃ between hot plates for 1 hour.
After heating for 0 minutes, it is cooled under pressure with a compression molding machine to a thickness of 0.7
A composite of jlml + glass fiber content of 30 vol% was molded. The tensile strength of this product was 1170~.

Comparative Example 2 A total of two fiberglass rovings, one glass fiber roving used in Comparative Example 1 and 21 polypropylene split cars used in Example 1, were used for each of the warp and weft yarns, and a hand loom with a thickness of about 12 nm and a fabric weight was used. A plain weave mixed fiber of 1050 y/m' and a glass fiber content of 30 vol 1% was woven. When this mixed fiber was compression molded in the same manner as in Example 2, the thickness was 0.
．． A composite of 7u was obtained with a tensile strength of 1200.

Example 3 Melt flow index (MFI) = o, 6I/10
100 parts of homopolypropylene, 0.5 parts by weight of maleic anhydride, 0.1 parts by weight of benzoyl peroxide, 0.0 parts of butylated hydroxytoluene (trade name BHT).
1 part by weight and 0.1 part by weight of calcium stearate were mixed in a Henschel mixer for 5 minutes, and melt-kneaded and pelletized at 190°C using a 40mp extruder with L/D = 24, resulting in MFI = 4. At L9/10 minutes, a modified polypropylene having a graft reaction of 0.23% by weight of maleic anhydride was obtained. Using this modified polypropylene, a blown film with a thickness of 1 U was formed, and after slitting, it was heated and stretched to obtain a flat yarn of 1000 denier. The glass fiber roving used in Example 1 was used for the warp, and the four flat yarns were used for the weft, and the thickness was approximately 1.3 at 4@ in the hand.
11131+ A plain weave mixed wire material with a basis weight of 1050 g/m' and a glass fiber content of 30 vol. Example 1 Two pieces of this mixed fiber were laid at right angles and the surroundings were fixed.
The composite was molded under heat and pressure in the same manner as above to obtain a composite with a thickness of 1.4 rugs. The glass fibers in this composite were uniformly arranged at equal intervals in the vertical and horizontal directions. The tensile strength of this composite is 1530%
Met.

Example 4 MF I =0.611/10 min homopolypropylene 100 parts by weight # γ-methacrylic acid dipropyltrimethoxysilane 0.5 parts by weight, dicumyl peroxide 0.1 parts by weight, BHTo, 1 part by weight and 0.1 part by weight of calcium stearate were mixed in a Henschel mixer for 5 minutes, and then mixed in a 40 m, $ extruder with L/D = 24 for 20 min.
Do not perform melt cross-wire beletization at 0°C, M F I =5
．． A modified polypropylene of 4 I/10 min was obtained. Using this modified polypropylene, the same procedure as in Example 3 was carried out to obtain a composite having a thickness of 14 rugs. The glass fibers in this composite were uniformly arranged at equal intervals in the vertical and horizontal directions. The tensile strength of this composite was 1570~.

Example 5 Using 1800 denier carbon fiber roving for the warp and 3000 denier polyetheretherketone fiber for the weft, a plain weave mixed fabric with a thickness of approximately 0.6 W + basis weight 600 g/m' and a carbon fiber content of 30 VO1% was woven. . Two sheets of this mixed fiber were stacked perpendicularly and heated to 400°C for 10 minutes on a hot plate.
After preheating for minutes, it is cooled under pressure by a compression molding machine to a thickness of 0.7
A composite with a carbon fiber content of 30 vol. 1% was obtained. The carbon fibers in this composite were uniformly arranged at equal intervals in the vertical and horizontal directions, and the tensile strength was 3500%. This composite was heated and melted to 370℃ using an infrared heating material, and hot stamped using a stamping mold to form a mold with a diameter of 5 mm.
When a cup with a depth of 20 m was molded, a beautiful molded product was obtained.

Example 6 The glass fiber p-ping used in Example 1 was used for the warp, and the 1000 denier polypyrene flat yarn was used for the weft, and the thickness was approximately Q, 8 m + basis weight 7801 using a hand loom.
1/11 *A plain weave mixed fiber with a glass fiber content of 62 vo1% was woven.

Two sheets of this fabric are stacked orthogonally, two polypropylene sheets with a thickness of 0.2 are placed on both sides, the periphery of the fabric is fixed, and after preheating between hot plates for 200'clo, it is molded in a compression molding machine. A composite with a thickness of 0.7 mm was obtained by cooling under pressure. The glass fibers in this composite were uniformly arranged at equal intervals in the vertical and horizontal directions. The tensile strength of this composite was 1430%.

Claims (1)

[Scope of Claims] 1) A woven fabric in which the weft (or warp) is a thermoplastic resin fiber and the warp (or weft) is a reinforcing fiber is prepared at a temperature higher than the melting temperature of the thermoplastic resin and at a melt concentration of the reinforcing fiber. 2) A method for manufacturing a composite, characterized in that the composite is molded by heating and pressurizing at the following temperature. 2) A method for manufacturing a composite according to claim 1, wherein the thermoplastic resin is polypropylene or polyether ether ketone. 3) Reinforcing fibers. 4) The thermoplastic resin is a modified polyolefin obtained by grafting unsaturated carboxylic acids or unsaturated silane compounds onto a polyolefin, and the reinforcing fiber is a glass fiber or a carbon fiber. 5) The manufacturing method according to claim 1, in which two or more woven fabrics are orthogonally laminated and heated and pressurized to form glass fibers. 6) The periphery of the woven fabric. 7) Manufacturing method according to claim 1, in which a thermoplastic resin sheet is laminated on a woven fabric and molded by heating and pressing in a fixed state. Method