JP2019123242A - Blank for obtaining fiber-reinforced resin molded body - Google Patents

Abstract

To provide a fiber-reinforced resin molded body having excellent mechanical property and high quality by uniformly and sufficiently mixing reinforced fibers formed of continuous fibers and a matrix resin between reinforced fibers composed of fibers.CONSTITUTION: There is provided a blank that is formed of laminating a plurality of woven fabrics composed of continuous fibers, and the continuous fibers constituting the woven fabrics contain at least conjugate fibers in which two kinds of thermoplastic polymers having melting points different from each other are conjugated, and the woven fabrics are composed of containing at least two kinds of thermoplastic polymers having melting points different from each other, and each of the laminated woven fabrics are united by melting or softening a polymer having a lowest melting point among the thermoplastic polymers constituting the woven fabrics. The blank is heat-molded with a predetermined molding die to melt the polymer having a low melting point and not melt the polymer having a high melting point for maintaining a shape of the fibers, both of which are constituting the blank, and then the resulting material is formed into a predetermined shape, and cooling and solidifying thereof are performed to obtain a fiber-reinforced resin molded body.SELECTED DRAWING: None

Description

The present invention relates to a base plate for obtaining a fiber-reinforced resin molded body and a method for producing a fiber-reinforced resin molded body using the base plate.

A fiber reinforced resin material is a composite material excellent in mechanical properties composed of reinforcing fibers and a matrix resin, and is used for ships, aircraft, machinery, members of automobiles and the like. For example, it is manufactured by laminating a prepreg sheet comprising reinforcing fiber and matrix resin and shaping it into a predetermined shape, or a method of impregnating a preform comprising reinforcing fiber with a matrix resin.
By using high strength and high modulus fibers such as glass fibers, carbon fibers and aramid fibers as the reinforcing fibers, a resin material having excellent mechanical properties can be obtained. When the reinforcing fiber is an inorganic fiber, it is difficult to recycle the used product, and when it is used for a product having a large amount of bending, the reinforcing fiber may not have a sufficient reinforcing effect. Composite materials using only fibers made of a plastic resin have also been studied. As a matrix resin, a thermosetting resin or a thermoplastic resin is used, but the latter has a short cycle time during molding and is being developed in the automotive field and the like. As a composite material suitable for automobile interior materials using a thermoplastic resin as a matrix resin, for example, Patent Document 1 wet-disperses a reinforcing fiber having a fiber length of 5 to 100 mm and a thermoplastic resin in particle form or fiber form There is disclosed a method of obtaining a stampable sheet (base plate) by needling on a sheet formed by a method and heating and compressing.

  When a thermoplastic resin is selected as the matrix resin, the thermoplastic resin has a certain viscosity even during melting, so it is difficult to impregnate the molten thermoplastic resin uniformly and sufficiently between the reinforcing fibers, but the technique of Patent Document 1 According to the above, there is an advantage that the thermoplastic resin in the form of particles or fibers and the reinforcing fibers are mixed by the wet dispersion method, so that they can be uniformly mixed easily.

Unexamined-Japanese-Patent No. 2004-217829 (Claims, Paragraph No. 0001, 0025-0027)

  When the reinforcing fiber is a short fiber having a fiber length of 5 to 100 mm, mixing is easy as in Patent Document 1 described above, but when the reinforcing fiber is a continuous fiber, the above method can not be applied. As a method of integrating a reinforcing layer made of continuous fibers and a matrix resin, for example, a method of integrating a laminate of a film made of a thermoplastic resin and a sheet made of reinforcing fibers by heat treatment, continuous powdery thermoplastic resin Examples of the method include a method of heat treatment after supporting the reinforcing fiber sheet by spraying or the like, a method of heat treating after coating a thermoplastic resin on the surface of the sheet made of the reinforcing fibers, and the like. An object of the present invention is to provide a high-quality fiber-reinforced resin molded article excellent in mechanical properties by blending a matrix resin between reinforcing fibers composed of continuous fibers more uniformly and sufficiently.

  The present invention achieves the above-mentioned subject, and makes the following a gist.

  That is, the present invention is an element plate for obtaining a fiber-reinforced resin molded product, in which a plurality of woven fabrics constituted by continuous fibers are laminated, and the continuous fibers constituting the woven fabric have different melting points 2 The woven fabric is constituted by including at least two kinds of thermoplastic polymers different in melting point, and the laminated woven fabrics constitute a woven fabric. Among the thermoplastic polymers, the polymer having the lowest melting point is integrated by melting or softening, and the gist of the invention is a sheet material.

  Hereinafter, the present invention will be described in detail.

  The base plate for obtaining the fiber-reinforced resin molded product of the present invention is formed by laminating a plurality of woven fabrics constituted by continuous fibers, and the woven fabric contains at least two thermoplastic polymers having different melting points. There is. Of the two types of thermoplastic polymers having different melting points, the low melting point polymer becomes the matrix resin of the resin molded body, and the high melting point polymer maintains the fiber form and becomes the reinforcing fiber in the resin molded body. In the present invention, the softening point is regarded as the melting point for an amorphous polymer which does not have a definite melting point.

  The reason why a woven fabric composed of continuous fibers is selected as a reinforcing fiber in a fiber-reinforced resin molded product is that it is excellent in mechanical strength and dimensional stability. For example, non-woven fabrics are those in which constituent fibers are randomly arranged, but compared to such non-woven fabrics, fibers are uniformly arranged in a woven fabric, and the directionality of physical properties can be easily controlled.

  The woven fabric in the present invention comprises at least two different melting point thermoplastic polymers. Further, the continuous fiber constituting the woven fabric is at least constituted by a composite fiber consisting of a high melting point polymer and a low melting point polymer. For example, a core-sheath type composite fiber in which the core part is a high melting point polymer and the sheath part is a low melting point polymer, and a side-by-side type composite fiber in which a high melting point polymer and a low melting point polymer are laminated. Moreover, using the multifilament yarn with which the fiber which consists of a high melting point polymer and the fiber which consists of a low melting point polymer are mixed by the desired ratio as a continuous fiber which comprises a woven fabric is mentioned. Furthermore, using a filament or multifilament yarn comprising a high melting point polymer and a filament or multifilament yarn comprising a low melting point polymer, when weaving a fabric, the respective yarns are arranged in an appropriate ratio to perform weaving. What is clothed is mentioned. The continuous fibers may be subjected to twisting, false twisting, interlacing, taslan processing, etc. as necessary, and when obtaining a woven fabric, spun yarn or slit yarn may be used in combination.

  Specific examples of the combination of the high melting point polymer and the low melting point polymer include polyethylene terephthalate / polypropylene, polyethylene terephthalate / polyethylene, polyethylene terephthalate / polyamide, polyethylene terephthalate / low melting point polyester copolymer, and the like.

  The woven structure of the woven fabric is not particularly limited, but plain weave, twill weave, satin weave, and multiple weave can also be used.

  A plurality of such woven fabrics are laminated, and the polymer having the lowest melting point of the thermoplastic polymers constituting the woven fabric is melted or softened, whereby the laminated woven fabrics are integrated, and the fiber is reinforced. It becomes a base plate for obtaining a resin molding. The number of laminated layers may be appropriately selected according to the application of the fiber-reinforced resin molded product and the required performance and according to the structure of the woven fabric, and is 2 or more, and the upper limit is about 10 or so. It is difficult to maintain sufficient strength as a fiber-reinforced resin molded product with one woven fabric constituting the base plate.

  In the base plate in which the woven fabrics are laminated and integrated, the mass ratio of the high melting point polymer to the low melting point polymer is preferably high melting point polymer: low melting point polymer = 3 to 7; 7 to 3 . Here, the high melting point polymer is a reinforcing fiber when forming a fiber reinforced resin molded body, while the low melting point polymer is a matrix resin when forming a fiber reinforced resin molded body It is. If the amount of the high melting point polymer is less than this ratio, the ratio of the reinforcing fibers decreases, so that the impact resistance and the bending strength tend to decrease. On the other hand, when the amount of the high melting point polymer is larger than this ratio, the proportion of the low melting point polymer to be the matrix resin decreases, and the amount of the matrix resin is small to obtain a molded body by melting. It is difficult to become difficult and it is necessary to add the melted resin at the time of molding.

  In order to obtain a base plate for obtaining a fiber-reinforced resin molded product, a plurality of the woven fabrics described above are laminated, heat treatment is performed, and a polymer having the lowest melting point is melted among thermoplastic polymers constituting the woven fabric. Or softened, and the woven fabrics are integrated through the melted or softened polymer.

  As a heating means, a hot air treatment machine, a heat press machine, a heat roll machine etc. are mentioned. Among them, it is preferable to use a heat press machine or a heat roll machine because the integrated process can be efficiently performed by simultaneously applying heat and pressure. The purpose of the heat treatment is to unify a plurality of laminated woven fabrics, so that, among the thermoplastic polymers constituting the woven fabric, the polymers having the lowest melting point are melted or softened to form woven fabrics. It may be integrated. That is, when forming a molded body, it is not necessary to melt all the low melting point polymers which are polymers serving as matrix resin, and it is preferable to at least melt or soften the polymer having the lowest melting point. In addition, all the polymers (low melting point polymers) to be the matrix resin may be melted to form a blank. That is, the low melting point polymers constituting the woven fabric may be sufficiently melted, and they may be firmly integrated by melting so that the boundary between the laminated woven fabrics is unclear, or the low melting point polymer The layers may be integrated by being softened, and the boundaries between the laminated woven fabrics may be in a clear state. In the latter case, heat treatment may be performed at a temperature at which the low melting point polymer softens, and the set temperature of the heat treatment may be a temperature lower than the melting point of the low melting point polymer. When two or more low melting point polymers to be a matrix resin are contained, only the polymer having the lowest melting point is melted or softened, and the other low melting point polymer is heat treated to produce a blank. Alternatively, the treatment may be carried out at a temperature not affected by heat. That is, the woven fabric is constituted by including three types of thermoplastic polymers having different melting points, and the melting points of the three types of thermoplastic polymers A, B, and C having different melting points. The heat treatment temperature (Tx) is the melting point (Ta) of the thermoplastic polymer A, the melting point (Tb) of the thermoplastic polymer B, and the melting point (Tc) of the thermoplastic polymer C is Ta> Tb> Tc In the case of a low melting point polymer which becomes a matrix resin when the thermoplastic polymer B and the thermoplastic polymer C are formed into a molded product, the relationship with the set temperature (Tx) at the time of heat treatment is Ta. It is preferable to set> Tb> Tx> Tc. In the production of the blank, the low melting point polymer is not all melted in the blank but only the melting or softening degree to bond the woven fabrics with one another, and all the low melting point polymers are obtained at the stage of obtaining the molding. By melting the blank, the handleability of the blank becomes good, and by giving flexibility to the blank, it easily conforms to the shape of the molding frame at the stage of obtaining a molded body, and imparts a desired shape such as bending. Cheap.

  In addition, as cooling after heat processing, even if it is slow cooling, you may be active cooling by air cooling, using the metal mold | die cooled with the refrigerant | coolant, etc.

  The base plate obtained as described above is thermoformed with a predetermined molding die to melt the low melting point polymer (which will be a matrix resin) constituting the base plate, and the high melting point polymer is not melted but of the fiber The shape is maintained, a predetermined shape is shaped, and cooling and solidification are performed to obtain a fiber-reinforced resin molded body. In heat forming, a method of applying heat to the base plate in advance and then molding with a mold, a method of heat forming by heating in a mold, and a method of heat forming by applying heat in advance and further heating in a mold Any one may be used. In the heat molding, the high melting point polymer does not melt, and in order to maintain the fiber form, the resin molded body plays a role as a reinforcing fiber. Moreover, when carrying out thermoforming, you may laminate and use two or more raw boards as needed.

  Further, in the present invention, using a laminate obtained by laminating a plurality of woven fabrics as a material of the base plate, the thermal bonding between the woven fabrics is not performed in advance, and the woven fabrics are integrated at once and heat molded simultaneously. Thus, a fiber-reinforced resin molded body can also be obtained. That is, it is a woven fabric constituted by the above-mentioned continuous fibers, wherein the woven fabric is constituted by including at least two kinds of thermoplastic polymers different in melting point, and a plurality of the woven fabrics are laminated; The laminate is thermoformed in a predetermined molding die to dissolve the low melting point polymer (which becomes the matrix resin) constituting the woven fabric, and maintain the shape of the fiber without melting the high melting point polymer. , Forming a predetermined shape, and cooling and solidifying to obtain a fiber-reinforced resin molded body. The laminated body is formed by laminating two or more woven fabrics, and the upper limit of the number of laminated sheets is not limited, but may be appropriately selected according to the required performance of the molded body, but is about 10 sheets. In the case of heat molding, as described above, a method in which heat is applied to the laminate in advance and then molding in a mold, a method in which heating is performed in a mold for thermal molding, heat is applied in advance, and heating is also performed in a mold Any method of thermoforming may be used. In the heat molding, the high melting point polymer does not melt, and in order to maintain the fiber form, the resin molded body plays a role as a reinforcing fiber.

  According to the present invention, a fabric containing a high melting point polymer and a low melting point polymer is used as a material for obtaining a fiber-reinforced resin molded body, and when forming a molded body, the high melting point polymer becomes a reinforcing fiber The low melting point polymer is to be a matrix resin, and the high melting point polymer and the low melting point polymer are uniformly present in the form of fibers from the stage of the material, so the matrix resin and reinforcing fibers are uniform. It is possible to obtain a molded body present in

  Next, the present invention will be specifically described based on examples, but the present invention is not limited to these examples.

Example 1
1670 dtex / 192f multifilament yarn (A) comprising a core-sheath composite filament in which polyethylene terephthalate (melting point 250 ° C.) is disposed in the core and polyester copolymer (melting point 160 ° C.) comprising ethylene terephthalate as the main repeating unit in the sheath Got ready. The core-sheath ratio of the core-sheath composite filaments was core: sheath = 2.7: 1 in volume ratio.

  A multifilament yarn consisting of the core-sheath composite filaments was placed on the warp and weft to produce a plain weave woven fabric. The weave density was 25 yarns / inch for both reasons.

  Three sheets of the obtained woven fabric are stacked, and heat and pressure treatment is performed under the condition of 0.5 MPa pressure in a press heated to 180 ° C. Thereafter, the mixture is gradually cooled at room temperature to form constituent fibers and woven fabrics A heat-sealed blank was obtained.

Example 2
A multifilament yarn (C) of 1100 dtex / 96 f consisting of a core-sheath composite filament in which a polyethylene terephthalate (melting point 250 ° C.) is disposed in the core and a polyester copolymer (melting point 160 ° C.) comprising ethylene terephthalate as the main repeating unit in the sheath Got ready. The core-sheath ratio of the core-sheath composite filaments was core: sheath = 2.7: 1 in volume ratio.

  On the other hand, a 1100 dtex / 192 f multifilament yarn consisting of a single-phase polyester filament consisting only of polyethylene terephthalate was prepared, and four multifilament yarns were twisted to prepare a twisted yarn.

  The multifilament yarn consisting of the above-mentioned core-sheath composite filaments was used for the warp, the double-twisted yarn was arranged for the weft, and a woven fabric was produced with a structure of 1/3 double-sided weave. The weave density was 113 yarns / inch and 14 yarns / inch.

  Three sheets of the obtained woven fabric are stacked, and heat and pressure treatment is performed under the condition of 0.5 MPa pressure in a press heated to 180 ° C. Thereafter, the mixture is gradually cooled at room temperature to form constituent fibers and woven fabrics A heat-sealed blank was obtained.

The base plates of the obtained Examples 1 and 2 were heated in an atmosphere of 180 ° C., and then molded using a flat plate mold consisting of a male mold and a female mold to obtain a flat reinforcing fiber molding.

Claims (6)

It is a base plate for obtaining a fiber-reinforced resin molded product, in which a plurality of woven fabrics composed of continuous fibers are laminated, and the continuous fibers constituting the woven fabric are two kinds of thermoplastic polymers having different melting points. Among the thermoplastic polymers constituting the woven fabric, the woven fabric is constituted by including at least two kinds of thermoplastic polymers having different melting points, and A blank characterized in that a polymer having the lowest melting point is integrated by melting or softening. A method for producing a blank for obtaining a fiber-reinforced resin molded article, comprising
A woven fabric comprising at least two kinds of thermoplastic polymers having different melting points, and at least a composite fiber composed of continuous fibers, wherein the continuous fibers are composed of two kinds of thermoplastic polymers having different melting points, Stack multiple sheets,
Next, heat treatment is performed to melt or soften the polymer having the lowest melting point among the thermoplastic polymers constituting the woven fabric, and the woven fabrics are integrated with each other. The heat treatment temperature is higher than the melting point of the polymer having the lowest melting point among the thermoplastic polymers constituting the woven fabric, and is lower than the melting point of the polymer other than the polymer having the lowest melting point The method according to claim 2, wherein the temperature is The base plate according to claim 2, characterized in that the set temperature in the heat treatment is a temperature at which the polymer having the lowest melting point of the thermoplastic polymers constituting the woven fabric is softened. Production method. A low melting point polymer constituting the base plate is melted by thermoforming the base plate according to claim 1 with a predetermined molding die, and the high melting point polymer is not melted to maintain the shape of the fiber, and the predetermined state is obtained. A method for producing a fiber-reinforced resin molded article, comprising the steps of: shaping and cooling to solidify the fiber-reinforced resin molded article. The low melting point polymer which comprises a base plate is melt | dissolved by thermoforming the base plate obtained by the manufacturing method of the base plate of any one of Claims 2-4 with a predetermined shaping | molding die, A method for producing a fiber-reinforced resin molded article, wherein the high melting point polymer is maintained without melting, the shape of the fiber is maintained, the predetermined shape is shaped, and the resin is cooled and solidified to obtain a fiber reinforced resin molded article.