JPH0617027B2 - Method for producing composite - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for producing a fiber-reinforced resin composite (hereinafter simply referred to as a composite) comprising a thermoplastic resin and reinforcing fibers. More specifically, the present invention provides a method for producing a composite in which a woven fabric in which a weft yarn and a warp yarn are composed of different thermoplastic resin fibers or reinforcing fibers is formed by heating and pressing.

[Prior Art] Conventionally, as a manufacturing method of a composite, for example, a method of impregnating a tow or woven fabric of reinforcing fibers with a thermosetting resin and curing, a method of applying resin powder to the reinforcing fibers or its woven fabric, and then adding A method of melting and impregnating the resin powder into the tissue under pressure has been proposed. However, these methods have problems in handling such that the prepreg intermediate is sticky and it is difficult to process the obtained composite into a complicated shape.

On the other hand, recently, a method of heating a continuous fiber tow having a mixture of a spun fiber of a thermoplastic polymer and a non-thermoplastic reinforcing fiber, particularly a carbon fiber in a specific ratio to a temperature higher than the melting point of the thermoplastic polymer fiber ( JP-A-60-209033,
JP-A-60-209034), a method of laminating a woven fabric in which the warp is a non-carbon fiber and the weft is a carbon fiber with a thermosetting resin layer which is a constituent element of the prepreg (JP-A-58-2).
No. 01824) has been proposed.

[Problems to be Solved by the Invention]

However, the composite obtained by the above-mentioned proposed production method does not satisfy all the required functions, and in particular, the orientation of the reinforcing fibers is uniform (the fibers are easily aligned), and the crimp (bending) is performed. ), There is no reduction in strength, and the performance of the thermoplastic resin having good wettability of the reinforcing fiber and excellent workability is demanded. Therefore, an object of the present invention is to provide a manufacturing method suitable for easily obtaining a composite having the above-mentioned properties.

[Means for Solving the Problems]

As a result of earnest studies in view of the above problems, the present inventors mold a woven fabric in which a weft yarn or a warp yarn is composed of mutually different fibers of a thermoplastic resin fiber or a reinforcing fiber under heating at a specific temperature. As a result, it was found that the orientation of the reinforcing fibers is uniform, the strength is not reduced by crimping, and the composite having no tackiness and excellent workability can be easily obtained, and the present invention has been proposed. . That is, according to the present invention, a woven fabric in which the weft (or warp) is made of thermoplastic resin fiber and the warp (or weft) is made of reinforcing fiber is used at a temperature not lower than the melting temperature of the thermoplastic resin and not higher than the melting temperature of the reinforcing fiber. There is provided a method for producing a composite body, which comprises heating and pressurizing at 1. In particular, in the present invention, the reinforcing fiber made of a thermoplastic resin is particularly strong by molding by heating and pressing in a state in which two or more of the above-mentioned fabrics are laminated or a thermoplastic resin sheet is laminated in the fabric. A composite with good wetting of is obtained.

Examples of the thermoplastic resin of the present invention include polypropylene, vinyl chloride resin, vinyl acetate resin, polystyrene,
ABS resin, acrylic resin, polyethylene, fluorine resin, polyamide resin, polyester resin, acetal resin, polycarbonate, polyetherimide, polyetherketone, polyetheretherketone, polysulfone, polyethersulfone polyphenylene sulfide, liquid crystal polymer and Known compounds such as a mixture thereof are not particularly limited, but polypropylene is generally used, and polyether ether ketone is preferably used particularly for applications requiring high strength.

The above-mentioned thermoplastic resin can be used as it is (unmodified), but it is particularly effective to use a modified polyolefin obtained by grafting an unsaturated carboxylic acid or an unsaturated silane compound onto the polyolefin. That is, a woven fabric composed of such modified polyolefin fibers and glass fibers, or a composite obtained by molding a laminate of the woven fabric and a sheet by heating and pressing, has good adhesion between the polyolefin resin and the glass fibers. It is preferable because the strength is increased. Such modified polyolefin can be obtained by a conventionally known method. That is, modified polyolefins grafted with unsaturated carboxylic acids are prepared by using unsaturated carboxylic acid monomers such as acrylic acid, maleic acid, itaconic acid, maleic anhydride, and itaconic anhydride as radical generators such as organic peroxides. It can be obtained by carrying out a graft reaction with polyolefin in the presence of a known method such as a solution state, a molten state or a slurry state. In addition, the modified polyolefin in which unsaturated silane compounds are grafted is a polyolefin and an unsaturated silane compound monomer such as vinyltrimethoxysilane, vinyltriethoxysilane, or γ-methacryloyloxypropyltrimethoxysilane as an organic peroxide. It can be produced by a method of reacting in a molten state in the presence of such a radical generator. In addition, these modified polyolefins can also be used as a mixture with an unmodified polyolefin. The amount of the unsaturated carboxylic acid or unsaturated silane compound which has been graft-reacted is generally 0.01 to 1% by weight based on the total resin.

The thermoplastic resin fibers used in the present invention include stretched or unstretched fibers, filaments, monofilaments, yarns, tapes, staples, ribbons made of the above-mentioned thermoplastic resins, and twisting these, or using a sizing agent. It is a generic term that includes things such as focused ones. The method for producing such a thermoplastic resin fiber is not particularly limited. For example, a filament melt-extruded from the spinneret is cooled and solidified while being drafted and wound up, and then stretched and heat-treated as necessary, after forming the film. If necessary, stretching or slitting may be performed. The thickness of the fiber thus obtained is not particularly limited, but generally 10 to 10,000 denier is suitable.

The thermoplastic resin sheet used in the present invention is obtained by subjecting the above-mentioned thermoplastic resin to extrusion molding, compression molding, injection molding, or the like, and the thickness of the sheet is the thickness of the fabric to be laminated or the composite. Generally, a sheet having a thickness of 0.1 to 10 mm is preferably used, though it depends on the final reinforcing fiber content in the body.

The reinforcing fiber used in the present invention is a reinforcing fiber having a melting temperature higher than that of the thermoplastic resin used, and examples thereof include glass fiber, carbon fiber, aramid fiber, boron fiber, ceramic fiber, metal fiber and synthetic resin. Fibers and the like can be mentioned, but when used in combination with the modified polyolefin described above, glass fiber is preferable, and carbon fiber is particularly preferable for applications requiring high strength. Any form of fiber such as single yarn, roving, yarn can be used, and the thickness of the fiber is not particularly limited.
Generally, fibers having a fiber diameter of 10 to 10,000 denier are preferably used.

It is important that the woven fabric (general term including woven fabric) used in the present invention is the above-mentioned thermoplastic resin fiber and reinforcing fiber woven in a specific configuration. That is, weft (or diameter)
Is a thermoplastic resin fiber, and the warp (or weft) must be composed of reinforcing fibers. When a thermoplastic resin fiber and a reinforcing fiber or a mixed fiber thereof are used for the weft (or warp), weaving At the same time, the reinforcing fibers crimp each other, which causes heating and pressurization to reduce the strength of the composite after molding, or because the thermoplastic resin fibers in the woven fabric melt during heating and pressurization, the fiber orientation is disturbed. However, the desired object of the present invention such as deterioration of moldability and processability of the obtained composite cannot be achieved.

The mixing ratio of the thermoplastic resin fiber and the reinforcing fiber in the above-mentioned woven fabric depends on the application of the composite, whether or not the thermoplastic resin sheet is laminated, and when the thermoplastic resin sheet is laminated, the thermoplastic resin sheet to be laminated. The thickness is selected as appropriate. When the thermoplastic resin sheet is not laminated, the reinforcing fiber is generally 5 to 70% by volume (vo
1%), especially 10 to 50 vol%. When the mixing (content) amount of the reinforcing fibers is less than 5 vol%, the reinforcing effect is small, and when the mixing amount exceeds 70 vol%, impregnation of the thermoplastic resin at the time of heat and pressure molding becomes insufficient. Moreover, when laminating | stacking a thermoplastic resin sheet, the mixing amount of the reinforcing fiber is generally 5 to 95 vol% with respect to the entire woven fabric, and especially 30
90 vol% is preferable. If the mixing amount is less than 5 vol%, the reinforcing effect is small, and if it exceeds 95 vol%, the wetting improving effect of the reinforcing fiber by the thermoplastic resin is lowered. The coarseness of the weft yarn or the warp yarn can be arbitrarily changed as required.

For the weaving, a known machine such as a hand loom or an automatic loom can be used to weave into a structure such as a plain weave, a twill weave, and a satin weave.
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-mentioned woven fabric or, if necessary, the woven fabric and the thermoplastic resin sheet, and heating and pressurizing them.

When the woven fabric is molded by heating and pressing, either one woven fabric or a plurality of woven fabrics can be laminated, but in particular, two or more woven fabrics are laminated at any angle, particularly preferably orthogonally. Is preferable in order to increase the strength of the obtained composite. On the other hand, in the case of laminating a woven fabric and a thermoplastic resin sheet and molding them by heating and pressing, the embodiment in which the woven fabric and the thermoplastic resin sheet are laminated is one layer each, sheet / fabric / sheet / fabric / sheet ... When a plurality of woven fabrics and sheets are laminated or two or more woven fabrics are used, each woven fabric is laminated at an arbitrary angle, or two or more woven fabrics are arbitrarily formed in each woven fabric layer Can be stacked at an angle of. At this time, the thermoplastic resin for the sheet and the thermoplastic resin in the fabric may be different resins, but it is preferable to use the same resin. When the reinforcing fiber is glass fiber and a modified polyolefin grafted with a thermoplastic resin or an unsaturated carboxylic acid or an unsaturated silane compound is used, the modified polyolefin is particularly used for the thermoplastic resin fiber constituting the woven fabric. The thermoplastic resin sheet may be either unmodified or modified polyolefin.

The heating in the present invention needs to be performed at a temperature not lower than the melting temperature of the thermoplastic resin and not higher than the melting temperature of the reinforcing fiber,
Outside the temperature range, the good composite of the present invention cannot be obtained. 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 laminating a woven fabric and a thermoplastic resin sheet and molding by heating and pressing, from two tee (T) -die extruders on both sides of the woven fabric heated above the melting temperature of the thermoplastic resin fiber. A method of laminating extruded thermoplastic resin molten sheets and pressurizing with a nip roll is preferable. In addition, when molding by heating and pressurizing, in order to prevent shrinkage due to melting of the resin, it is preferable to fix the periphery of the woven fabric but to apply tension, and the composite thus obtained is particularly reinforced. It is possible to obtain a product having a good arrangement of the fibers for use, a good appearance, and a more excellent strength.

[Action effect]

Generally, it is very difficult to uniformly align and fill the reinforcing fibers in the thermoplastic resin. However, according to the present invention, a weave (or warp) or a thermoplastic resin fiber, the warp (or weft) is a woven fabric composed of reinforcing fibers, or a laminate of a woven fabric and a thermoplastic resin sheet is heated and pressed. The thermoplastic resin fiber and the thermoplastic resin sheet are melted while the reinforcing fibers are evenly arranged, and a composite in which the reinforcing fibers are uniformly oriented can be easily prepared by molding. Further, particularly when laminating two or more fabrics at an arbitrary angle and molding by heating and pressing, the reinforcing fibers are not woven, so that the reinforcing fibers in each direction are uniformly oriented, and crimps (bends) are formed. ) Is small, and a composite having excellent aesthetics and strength can be obtained. The composite obtained in the present invention can 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 result measured based on the following method. That is, from the composite, cut a rectangular test piece with a width of 2 cm and a length of 15 cm in each of the vertical and horizontal directions, and use a tensile tester to measure the distance between the chucks 5
cm, tensile speed 10mm / min
The tensile strengths in the longitudinal direction and the transverse direction were measured, and the average value of the two was taken as the tensile strength unless otherwise specified.

Example 1 A glass fiber roving of 4500 denier was used for the warp and a polypropylene split yarn of 4000 denier was used for the weft, a thickness of about 1.2 mm and a basis weight of 1100 g / m using a hand loom.
^2. Woven plain weave mixed fabric with a glass fiber content of 30 vol% was woven. This fabric is fixed in the warp direction and is heated between the hot plates for 200
After heating at 0 ° C. for 10 minutes, it was pressed and cooled by a compression molding machine to obtain a composite having a thickness of 0.7 mm. The glass fibers in this composite were neatly arranged in parallel at equal intervals. The tensile strength of this composite in the glass fiber orientation direction was 1350 kg / cm ² .

Example 2 Two mixed woven fabrics used in Example 1 were stacked orthogonally, the periphery was fixed, and the mixture was heated and pressed in the same manner as in Example 1 to form a composite having a thickness of 1.4 mm. The glass fibers in this composite were evenly arranged in the longitudinal and transverse directions at equal intervals. The tensile strength of this composite was 1370 kg / cm ² .

Comparative Example 1 4500 denier glass fiber roving was woven with a hand loom into a plain weave having a thickness of about 0.4 mm and a basis weight of 520 g / m ² . This glass fiber woven fabric is sandwiched between two polypropylene sheets having a thickness of 0.3 mm, heated at 200 ° C. for 10 minutes between hot plates, and then pressure-cooled by a compression molding machine to have a thickness of 0.7 mm. A 30 vol% composite was molded. The tensile strength of this product was 1170 kg / cm ² .

COMPARATIVE EXAMPLE 2 A warp and a weft were each made up of one glass fiber roving used in Comparative Example 1 and one polypropylene split yarn used in Example 1 for a total of two, and a thickness of about 1.2 mm was obtained on a hand loom. A plain weave mixed woven fabric having a basis weight of 1050 g / m ² and a glass fiber mixing ratio of 30 vol% was woven. When this mixed woven fabric was compression-molded in the same manner as in Example 2, a composite having a thickness of 0.7 mm was obtained and the tensile strength was 1200 kg / cm ² .

Example 3 100 parts by weight of homopolypropylene having a melt flow index (MFI) of 0.6 g / 10 min, 0.5 part by weight of maleic anhydride, 0.1 part by weight of benzoyl peroxide, butylated hydroxytoluene (BHT) 0.
1 part by weight and 0.1 part by weight of calcium stearate are mixed with a Henschel mixer for 5 minutes, and L / D = 24 4
Melt-kneading pelletization was carried out at 190 ° C. by a 0 mmφ extruder to obtain a modified polypropylene having MFI = 4.5 g / 10 minutes and graft reaction maleic anhydride amount of 0.23% by weight. Using this modified polypropylene, an inflation film having a thickness of 1 mm is formed into a film, slit, and then heated and stretched to 100
A flat yarn of 0 denier was obtained. The glass fiber roving used in Example 1 was used as the warp yarn, and the above-mentioned four flat yarns were used as the weft yarns.
A plain weave mixed woven fabric having m ² and a glass fiber mixing ratio of 30 vol% was woven. Two pieces of this mixed woven fabric were stacked orthogonally to each other, the periphery was fixed, and the mixture was heated and pressed in the same manner as in Example 1 to obtain a composite having a thickness of 1.4 mm. The glass fibers in this composite were evenly arranged in the longitudinal and transverse directions at equal intervals. The tensile strength of this composite is
It was 1530 kg / cm ² .

Example 4 MFI = 0.6 g / 10 min homopolypropylene 100
Parts by weight, .gamma.-methacryloxypropyltrimethoxysilane 0.5 parts by weight, dicumyl peroxide 0.1 parts by weight, BHT 0.1 parts by weight and calcium stearate 0.1 parts by weight are mixed with a Hensiel mixer for 5 minutes, L
Melt-kneading pelletization was performed at 200 ° C. with a 40 mmφ extruder with / D = 24 to obtain a modified polypropylene having MFI = 5.4 g / 10 min. Using this modified polypropylene,
The same procedure as in Example 3 was carried out to obtain a composite having a thickness of 1.4 mm. The glass fibers in this composite were evenly arranged in the longitudinal and transverse directions at equal intervals. The tensile strength of this composite is 1570kg
It was / cm ² .

Example 5 A 1800 denier carbon fiber roving was used for the warp, and 3000 denier polyether ether ketone fiber was used for the weft, and a plain weave mixed identification having a thickness of about 0.6 mm, a basis weight of 600 g / m ² , and a carbon fiber content of 30 vol% was woven. . Two pieces of this mixed woven fabric were stacked orthogonally to each other, preheated by a hot plate at 400 ° C. for 10 minutes, and then pressure-cooled by a compression molding machine to obtain a composite having a thickness of 0.7 mm and a carbon fiber content of 30 vol%. The carbon fibers in this composite were evenly arranged in the longitudinal and transverse directions at equal intervals, and the tensile strength was 3500 kg / cm ² . This composite was heated and melted with an infrared heating material at 370 ° C. and hot stamped with a stamping die to obtain a diameter of 50 mmφ and a depth of 2
When a 0 mm cup was molded, a clean molded product was obtained.

Example 6 The glass fiber roving used in Example 1 was used as the warp, and the polypropylene weft of 1000 denier was used as the weft, and the thickness was about 0.8 mm with a handloom machine, the basis weight was 780 g / m ² , and the glass fiber mixing ratio was 62 vol%. Woven plain weave mixed woven fabric.
Two pieces of this fabric are stacked orthogonally, and the thickness is 0.2mm on both sides.
2 polypropylene sheets were placed, the periphery of the fabric was fixed, preheated at 200 ° C. for 10 minutes between hot plates, and then pressure-cooled by a compression molding machine to obtain a composite having a thickness of 0.7 mm. The glass fibers in this composite were evenly arranged in the longitudinal and transverse directions at equal intervals. The tensile strength of this composite was 1430 kg / cm ² .

Continuation of the front page (51) Int.Cl. ⁵ Identification number Office reference number FI technical display location D03D 15/00 Z 7199-3B B29K 23:00 105: 06

Claims (7)

[Claims] 1. A woven fabric in which a weft (or warp) is composed of a thermoplastic resin fiber and a warp (or weft) is composed of a reinforcing fiber at a temperature not lower than the melting temperature of the thermoplastic resin and not higher than the melting temperature of the reinforcing fiber. A method for producing a composite, characterized in that 2. The method according to claim 1, wherein the thermoplastic resin is polypropylene or polyether ether ketone. 3. The manufacturing method according to claim 1, wherein the reinforcing fiber is glass fiber or carbon fiber. 4. The production method according to claim 1, wherein the thermoplastic resin is a modified polyolefin obtained by grafting an unsaturated carboxylic acid or an unsaturated silane compound on the polyolefin, and the reinforcing fiber is a glass fiber. 5. The method according to claim 1, wherein two or more woven fabrics are laminated at right angles and molded by heating and pressing. 6. The manufacturing method according to claim 1, wherein the woven fabric is heated and pressed while the periphery of the woven fabric is fixed. 7. The manufacturing method according to claim 1, wherein the thermoplastic resin sheet is laminated on the woven fabric, and the woven fabric is heated and pressed to be molded.