JP2011016333A - Method for manufacturing fiber reinforced resin molded article - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a novel method for manufacturing by which a fiber reinforced resin molded article with a continuous cross sectional shape can be manufactured with stable physical property and good precision and which does not cause deterioration in a work environment.SOLUTION: In the method for manufacturing the fiber reinforced resin molded article, a composite fiber intermediate body 10 in which resin fiber 101 constituted by making matrix resin of a thermoplastic object in a fibrous form and reinforcing fiber 102 are pulled and aligned are introduced in a molding mold 3 and a resin fiber 101 is melted by heating the same in the molding mold 3. Further, the composite fiber intermediate body is continuously taken out from the molding mold 3 and solidified by cooling. The composite fiber intermediate body 10 is introduced while heating the molding mold 3 at a temperature at least a melting point of the matrix resin. It is preferable that the resin fiber 101 is arranged along the inner peripheral face of the passage 31 of the molding mold 3 at a high containing ratio.

Description

  The present invention relates to a method for producing a fiber-reinforced resin molded article having a continuous identical cross-sectional shape.

  Conventionally, when a product having a complicated shape with a continuous product having the same cross-sectional shape is molded, it is often manufactured by a profile extrusion molding method. In the profile extrusion molding method, a mold for shaping a desired shape is attached to the tip of the extruder, a plasticized resin is extruded through the mold with an extruder, and the molten resin is cooled and solidified. This is a method for obtaining a molded product.

  Further, as the fiber reinforced composite material, there are a fiber reinforced resin material (FRP), a fiber reinforced metal material (FRM), a fiber reinforced ceramic material (FRC), etc. Among them, the fiber reinforced resin material is lightweight and strong, It is used in a wide range of applications due to the advantage that products of various shapes can be made. Depending on the shape of the product, the fiber reinforced resin material may be molded manually, such as by hand lay-up method, by mechanical molding, by continuous molding, etc., but molded products having the same cross-sectional shape Is obtained continuously, a continuous molding method is used.

  For example, in the extrusion molding method disclosed in Patent Document 1, a bundle of reinforcing fibers such as glass fibers (roving) is hardened with a resin, guided into a mold, arranged in a deformed cross section, and the longitudinal rigidity is increased to strengthen the fiber. Resin material is manufactured.

  In addition, the pultrusion method is also used for molded products with irregular cross-sections, and the reinforcing fibers are aligned according to the required strength characteristics, impregnated with resin, and then formed into a mold having a predetermined cross-sectional shape. It is allowed to pass through and is cured while being continuously drawn to obtain a molded product.

  For example, Patent Document 2 describes a method in which a fiber bundle impregnated with a thermoplastic resin is heated, molded to a final cross-section having a final shape with a die, and then passed through a cooled die to fix the shape. ing. In Patent Document 3, the matrix resin and the reinforcing fiber are drawn into a mold and pulled out, and a thermoplastic resin rod having a predetermined shape is taken out and cut into a predetermined length by a pelletizer with a cutting blade. It is described that a molded product is obtained.

Japanese Patent Laid-Open No. 10-323878 Japanese Patent No. 2634184 JP 2004-267811 A

  However, in the conventional extrusion molding method, the resin heated in the extruder and in the mold is shrunk, deformed and solidified when it is cooled. It was difficult to do this, and there was a problem that the mold and the cooling device had to be lengthened or the amount of extrusion had to be reduced. In addition, when a crystalline polyolefin-based resin is used as a base material resin, the amount of shrinkage is large, and it is difficult to obtain an accurate molded product.

  In the conventional pultrusion molding method, it is necessary to align the reinforcing fiber material in accordance with the required strength characteristics, and immerse the aligned reinforcing fiber bundle in a liquid resin tank, and then draw it into the mold. In addition, the liquid mixed raw material obtained by mixing the liquid thermosetting resin raw material in the mixing section in the form of a continuous long fiber bundle while being aligned is discharged from a discharger, and the liquid mixed raw material is discharged into the long fiber bundle. Impregnated. In the molding method through the step of impregnating the liquid resin material in this way, there is a possibility that the uncured liquid resin material may drip in the transfer path from the impregnation step to the molding die, and the resin filling is insufficient. There was a problem that the physical properties after curing could not be controlled and became unstable. In addition, the liquid resin material that has dripped may adhere to various facilities, wall surfaces, floors, and the like in the path, and there is a problem that the working environment of the manufacturing process is deteriorated.

  Therefore, the present invention has been made in view of the above problems, and a fiber-reinforced resin molded article having a continuous cross-sectional shape is accurately manufactured with stable physical properties without causing deterioration of the working environment. Its main purpose is to make it a new manufacturing method.

  In order to achieve the above-mentioned object, a method for producing a fiber-reinforced resin molded article according to the present invention includes a composite fiber intermediate in which resin fibers in the form of a thermoplastic base material resin and reinforcing fibers are aligned. A step of introducing the composite fiber intermediate into the molding die, a heating step in which the introduced composite fiber intermediate is heated in the molding die to melt the resin fiber, and the composite fiber intermediate that has undergone the heating step is continuously removed from the molding die. The composite fiber intermediate is introduced in a state in which the molding die is heated to a temperature equal to or higher than the melting temperature of the base resin.

  With such a configuration, since the thermoplastic resin of the base material resin is mixed in advance with the reinforcing fibers in a fiber form, there is no possibility of dripping in the process leading to the preheating step and the introduction step. Therefore, since an appropriate content ratio between the base material resin and the reinforcing fiber is maintained throughout the entire process, the required strength and physical properties can be easily obtained, and stable quality can be ensured. Moreover, there is no possibility of contaminating the work environment, and a fiber-reinforced resin molded product can be suitably obtained.

  Further, in the method for manufacturing a fiber-reinforced resin molded article having the above-described configuration, the composite fiber intermediate may be subjected to a preheating step in which the composite fiber intermediate is preheated by passing through a preheating chamber in which hot air is generated. Good.

  As a result, pre-heat treatment can be performed to the inside of the composite fiber intermediate in a relatively short time, and the resin fibers can be sufficiently melted in the subsequent steps, and the line speed can be increased while ensuring stable quality. It becomes possible to improve.

  Moreover, in the composite fiber intermediate, if the ratio of the resin fiber that is a thermoplastic resin is smaller than that of the reinforcing fiber, the molded product becomes fragile, and conversely if the ratio of the resin fiber is large, the formability deteriorates. Therefore, it is preferable that the resin fiber and the reinforcing fiber are contained in the composite fiber intermediate in different proportions, and further, the resin fiber is contained in a high content ratio along the inner peripheral surface of the molding die. Preferably they are arranged. Thereby, a molded article can be obtained with a good shape and high accuracy.

  Moreover, in the manufacturing method of the fiber reinforced resin molded article of the said structure, it is preferable that the said base material resin is crystalline resin which has a predetermined softening temperature. Such a matrix resin improves heat resistance, rigidity, and the like by being combined with reinforcing fibers, but it is possible to obtain a tough and tenacious molded product with a smaller molding shrinkage rate.

  Moreover, in the manufacturing method of the fiber reinforced resin molded article of the said structure, it is preferable that the shaping die has formed the opening area of a metal mold entrance larger than the opening area of a metal mold exit. Thereby, a smooth molding process becomes possible and a molded product can be obtained efficiently.

  According to the method for producing a fiber-reinforced resin molded article of the present invention configured as described above, it is possible to produce a suitable molded article having stable physical properties and high accuracy and having a continuous cross-sectional shape and high surface smoothness. It becomes. Moreover, the problem that raw material resin adheres to various facilities in a shaping | molding path | route, a wall surface, a floor | bed, etc. and a working environment is deteriorated can also be eliminated.

It is explanatory drawing which shows roughly the manufacturing method of the fiber reinforced resin molded product which concerns on suitable embodiment of this invention. It is a conceptual diagram which shows an example of the composite fiber intermediate body in the manufacturing method which concerns on embodiment of this invention. It is a front view which shows an example of an introduction jig | tool. 4 is an enlarged view of the introduction jig of FIG. 3, FIG. 4 (a) is a partially enlarged front view, and FIG. 4 (b) is a partially enlarged sectional view. It is explanatory drawing which shows the example of arrangement | positioning of an introduction jig | tool. It is explanatory drawing which shows the cross-sectional shape of the shaping die in an Example. It is explanatory drawing which shows the fiber arrangement | positioning form of Example 1. FIG. It is explanatory drawing which shows the fiber arrangement | positioning form of Example 2. FIG.

  Hereinafter, the form for implementing the manufacturing method of the fiber reinforced resin molded product which concerns on embodiment of this invention is demonstrated, referring drawings.

  FIG. 1 is an explanatory view schematically showing a method for producing a fiber-reinforced resin molded article according to a preferred embodiment of the present invention, and FIG. 2 is a conceptual diagram showing an example of a composite fiber intermediate in the production method.

  As shown in the figure, the composite fiber intermediate 10 used for molding is formed by aligning resin fibers 101 and reinforcing fibers 102 in the form of a thermoplastic base material resin. In the fiber supply unit 1 shown in FIG. 1, reels 11... 11 around which thermoplastic resin fibers 101 and reinforcing fibers 102 are wound are set. The fibers unwound from each reel 11 are drawn together through the guide 12 and sent to the next process.

  Here, as the base resin of the thermoplastic resin fiber 101, a crystalline resin having a predetermined softening temperature and having heat resistance and impact resistance is used. Of the crystalline resins, polyolefin resins are suitable. For example, polyethylene, polypropylene, polyester, and the like are preferably used. In general, the higher the density, the higher the crystallinity, the higher the rigidity and strength, and the better the heat resistance, and the better the base resin. In addition, crystalline thermoplastic resins such as polyamide, polyacetal, and polyphenylene sulfide can also be used as the base material resin depending on the use of the molded product.

  For the reinforcing fiber 102, any of high-melting fibers such as glass fiber, carbon fiber, and aromatic polyamide fiber can be used. Among these, glass fibers are most preferable in view of the strength and price of the obtained fiber-reinforced resin molded product. Moreover, as a fiber diameter of the reinforcing fiber 102, 3-25 micrometers is preferable and 5-20 micrometers is more preferable from a strength surface and a price surface.

  In the present manufacturing method, the reinforcing fiber 102 may be yarn, strand, glass cloth, roving cloth, stitch or the like as a fiber form. Moreover, in order to improve adhesiveness with base material resin, it is preferable to pre-process with a silane coupling agent etc. When a fiber bundle is used, it is preferable that 50 to 2,000 fibers are bundled. More preferably, a bundle of 100 to 1,600 fibers is bundled.

  In the composite fiber intermediate 10, the resin fiber 101 and the reinforcing fiber 102 are contained in different proportions. If the proportion of the resin fiber 101 that is a thermoplastic resin is smaller than that of the reinforcing fiber 102, the molded product becomes brittle. If the ratio of the resin fiber 101 is too large, the formability deteriorates. A preferable content ratio is that the resin fiber 101 and the reinforcing fiber 102 are 20:80 to 80:20 in weight ratio. When the ratio of the resin fiber 101 is increased by adjusting the content ratio, it is possible to prevent the molded product from cracking and to improve water resistance.

  The composite fiber intermediate 10 may have a form in which the resin fibers 101 and the reinforcing fibers 102 are randomly arranged at the above-described content ratio. However, when the composite fiber intermediate 10 is introduced into the molding die 3, It is more preferable that the resin fibers 101 are arranged at a high content ratio along the peripheral surface. Thereby, the ratio of the thermoplastic resin that is the base material resin in the surface layer portion of the molded product is increased, and a relatively large amount of reinforcing fibers are disposed inside.

  The resin fibers 101 and the reinforcing fibers 102 aligned as described above are transferred to the next process as the composite fiber intermediate 10. The resin fibers 101 and the reinforcing fibers 102 are sent so as to be substantially parallel to the axis of the passage 31 of the molding die 3. In the illustrated embodiment, the preheating chamber 2 is provided as a preliminary process before the composite fiber intermediate 10 is introduced into the molding die 3.

  The preheating chamber 2 includes, for example, a hot air generator inside, and is provided with an inlet hole through which the composite fiber intermediate 10 passes and an outlet hole facing the inlet hole, and preheats the composite fiber intermediate 10 that passes therethrough. There is no limitation in particular as a hot air generator, A heating wire heating type blower, a gas heating type blower, an infrared heater etc. can be used.

  In the preheating chamber 2, the composite fiber intermediate 10 is preheated by blowing hot air (preheating process). The preheating chamber 2 can preheat the composite fiber intermediate 10 within a relatively short time, and the resin fibers 101 can be sufficiently melted in the subsequent steps to ensure stable quality. However, it becomes possible to improve the line speed.

  Subsequently, the composite fiber intermediate 10 that has undergone the preheating process is introduced into the molding die 3 having the passage 31 having a predetermined cross-sectional shape (introduction process). At the time of introduction, it is preferable that the fiber direction of the reinforcing fiber 102 of the composite fiber intermediate 10 is made to coincide with the axis of the passage 31 of the molding die 3. The molding die 3 is formed such that the opening area of the introduction port (mold inlet) 32 of the passage 31 is larger than the opening area of the extraction port (mold outlet) 33. The passage 31 between the introduction port 32 and the extraction port 33 has a tapered shape that is gradually reduced. If the opening area of the introduction port 32 is too small, it is difficult to introduce the composite fiber intermediate 10 in an aligned form. Conversely, if the opening area is too large, the molding die 3 itself must be made larger than necessary. Affects the heating efficiency. Therefore, the opening area of the introduction port 32 is preferably about 1.1 to 3.0 times the opening area of the extraction port 33.

  The introduced composite fiber intermediate 10 is heated in the molding die 3 to melt the resin fibers 101 (heating process). The heating means in the molding die 3 is preferably a method of heating the periphery of the passage 31 with a band heater or a method of casting a heater. Thereby, the inside of the passage 31 of the molding die 3 is maintained at a predetermined temperature. The mold temperature varies depending on the type of the base resin, but is heated to a temperature higher than the melting temperature of the base resin. When the mold temperature is lower than the melting temperature of the base resin, the reaction rate of the thermoplastic resin is deteriorated, and the heating time is required for a long time. Therefore, for example, the mold temperature is preferably about 130 to 150 ° C. if the base resin is low-density polyethylene, and is preferably about 200 ° C. if polypropylene.

  The composite fiber intermediate 10 melted by heating is continuously drawn out from the molding die 3 and transferred to the cooling device 4 to be cooled (solidification step). In the cooling device 4, the composite fiber intermediate body 10 formed into a predetermined cross-sectional shape by the molding die 3 is cooled and solidified. Examples of the cooling means include a method of blowing cold air (air cooling), passing through a water tank, or spraying water (water cooling). Further, these cooling means may be combined. In the embodiment illustrated in FIG. 1, the cooling device 4 includes a means for first performing water cooling with good cooling efficiency by the water sprayer 41 and then air-cooling by the cold air generator 42. I have. The water sprayer 41 and the cold air generator 42 are arranged above and below or on the left and right of the path.

  The molded product 100 that has been cooled and solidified through the cooling process and has a predetermined cross-sectional shape is taken up by the drawing device 5 and formed into a required length by the cutting machine 6, or is wound up as it is to obtain a long molded product. .

  As described above, according to the present manufacturing method, the thermoplastic resin of the base material resin is preliminarily mixed with the reinforcing fiber 102 in a fiber form, so there is no risk of dripping in the process leading to the preheating step and the introduction step, and therefore Since an appropriate content ratio between the base material resin and the reinforcing fiber is maintained throughout the entire process, the required strength and physical properties can be easily obtained, and stable quality can be ensured. Moreover, there is no possibility of contaminating the work environment, and a fiber-reinforced resin molded product can be suitably obtained.

  In the introduction step, the composite fiber intermediate 10 is introduced into the molding die 3 at a high ratio of the resin fibers 101 to the portion that becomes the surface layer portion of the molded product, and the reinforcing fibers 102 are relatively placed therein. As a method of introducing a large number, an introduction jig 7 illustrated in FIGS. 3 to 5 may be provided. 3 is a front view of the introducing jig, FIG. 4A is a partially enlarged view of the introducing jig, FIG. 4B is a partially enlarged sectional view of the introducing jig, and FIG. 5 is an introducing jig. It is explanatory drawing which shows the example of installation.

  The introduction jig 7 is formed corresponding to the outer shape of a desired molded product. In the illustrated form, a plurality of fiber guide paths 71 (71a, 71b) are formed so that the composite fiber intermediate 10 is in a preferred arrangement form corresponding to the cross-sectional shape of the introduction port 32 of the passage 31 of the molding die 3. Is provided. That is, in order to arrange a large proportion of the thermoplastic resin, which is the base material resin, in the surface layer portion of the molded product and arrange reinforcing fibers inside thereof, as shown in FIG. 3, the fiber guide path 71a of the resin fiber 101 (solid line) ) Are provided on the outside, and fiber guide paths 71b (broken lines) for the reinforcing fibers 102 are provided on the inside.

  These fiber guide paths 71a and 71b are provided with round holes through which the resin fibers 101 or the reinforcing fibers 102 are inserted, so that the resin fibers 101 and the reinforcing fibers 102 can be arranged in a desired arrangement form. Yes. As shown in FIG. 3, each fiber guide path 71a, 71b is assigned with an individual symbol, and any fiber guide path 71a, 71b can be specified individually. In the case of illustration, it is specified by 7 rows of 1 to 7 and 26 columns from A to Z, and whether to insert the resin fiber 101 for each of the fiber guide paths 71a and 71b or to insert the reinforcing fiber 102 Stipulated.

  As shown in FIGS. 4A and 4B, each fiber guide path 71a, 71b has a round hole 72 formed with an opening diameter larger than the fiber diameter. The fiber guide path 71a of the resin fiber 101 and the fiber guide path 71b of the reinforcing fiber 102 are specified not only by the row number × column symbol code but also by the edge 73 being formed in different colors. It is preferable that identification is possible. As a result, the resin fibers 101 or the reinforcing fibers 102 specified in the determined fiber guide paths 71a and 71b can be inserted, and a plurality of resin fibers 101 and the reinforcing fibers 102 can be arranged in a desired arrangement form. .

  The introduction jig 7 only needs to be disposed before the heating step, and is provided in front of the molding die 3. In the form shown in FIG. 5, they are arranged before and after the preheating chamber 2. As described above, the introduction jig 7 may be disposed at a plurality of locations in the process, or may be disposed at one location before the heating step. The composite fiber intermediate 10 passes through the introduction jig 7 so that when the resin fibers 101 and the reinforcing fibers 102 are introduced into the molding die 3, the resin fibers 101 are aligned along the inner peripheral surface of the passage 31. Arranged at a high content ratio. And the ratio of the thermoplastic resin which is base material resin becomes high in the surface layer part of a molded article, a comparatively many reinforcement fiber is arrange | positioned inside, and it becomes possible to ensure favorable surface smoothness and intensity | strength.

  Next, the manufacturing method of the fiber reinforced resin molded product which concerns on the Example of this invention is demonstrated.

  In Examples 1 and 2 and Comparative Examples 1 and 2, fiber reinforced resin molded products having irregular cross-sectional shapes were obtained using a molding die 3 having a passage 31 as shown in FIG.

  In the molding die 3, the passage 31 has a substantially gate-shaped modified cross-sectional shape, and the passage C dimension is smaller in width than the passage A dimension. Further, the dimension of the passage A is the same as the dimension of the passage B, and a passage D wider than the passage C is provided at the lower end portion of the passage C. Using the molding die 3 having such an irregular cross-sectional shape, the molded product obtained under each condition described in Table 1 is divided into each part as described in Table 2 in Examples 1 and 2 and Comparative Examples 1 and 2. The thickness and the angle of the corners were measured and evaluated.

<Example 1>
In Example 1, polypropylene fiber (30 μm strand) was used as the resin fiber 101. For the reinforcing fiber 102, glass fiber (18 μm strand) pretreated with a silane coupling agent was used.

  The content ratio of each fiber as the composite fiber intermediate 10 was 40:60 by weight of the polypropylene fiber and the glass fiber. Moreover, the arrangement | positioning form of the resin fiber 101 and the reinforcement fiber 102 was disperse | distributed and arrange | positioned at random. The molding method is based on the pultrusion method shown in FIG. As described above, when the arrangement form of the resin fibers 101 and the reinforcing fibers 102 is random, the composite fiber intermediate 10 is arranged as illustrated in FIG. 7 in the passage 31 of the molding die 3.

<Example 2>
In Example 2, the resin fiber 101 and the reinforcing fiber 102 are the same as in Example 1, and the content ratio is also the same as in Example 1. However, the arrangement form of the resin fibers 101 and the reinforcing fibers 102 as the composite fiber intermediate 10 is arranged at a high content ratio in the surface layer portion along the inner peripheral surface of the passage 31 as illustrated in FIG. In addition, a large number of reinforcing fibers 102 are arranged inside.

＜比較例１＞
比較例１では、母材樹脂にポリプロピレンを用い、滑剤（ステアリン酸亜鉛）を表１に示す割合で用いて、押出成形により異形断面形状の成形品を得た。

<Comparative Example 1>
In Comparative Example 1, a molded article having an irregular cross-sectional shape was obtained by extrusion molding using polypropylene as the base material resin and a lubricant (zinc stearate) in the ratio shown in Table 1.

<Comparative Example 2>
In Comparative Example 2, a molded article having an irregular cross-sectional shape by extrusion molding using polypropylene as a base material resin, glass fibers (chopped strands) as reinforcing fibers, and a lubricant (zinc stearate) in the ratio shown in Table 1. Got.

得られた成形品は、図６に示す各部の厚み寸法及び角度のほか、目視により、表面の平滑性について、非常に平滑（◎）、平滑（○）、又は部分的に凹凸有り（×）の３段階で評価した。

In addition to the thickness dimension and angle of each part shown in FIG. 6, the obtained molded product is very smooth (◎), smooth (◯), or partially uneven (×) in terms of surface smoothness. It was evaluated in three stages.

  Table 2 summarizes the evaluation of the molded products according to Examples 1 and 2 and the molded products according to Comparative Examples 1 and 2. As a result of the molding, the molded product had high dimensional stability in Examples 1 and 2, an almost predetermined thickness dimension was obtained, and the angle of the corner was good. In Examples 1 and 2, Example 2 was better in surface smoothness, and a molded article having a very smooth surface was obtained. In Comparative Examples 1 and 2, the dimension of the molded product was not stable, and in Comparative Example 2, it was difficult to extrude and a molded product having an irregular cross-section could not be obtained.

  INDUSTRIAL APPLICABILITY The present invention can be suitably used for manufacturing methods for fiber-reinforced resin molded products in a wide range of fields.

DESCRIPTION OF SYMBOLS 1 Fiber supply part 2 Preheating chamber 3 Molding die 31 Passage 32 Mold inlet 33 Mold outlet 4 Cooling device 5 Pull-out device 6 Cutting machine 7 Introducing jig 10 Composite fiber intermediate 101 Resin fiber 102 Reinforcing fiber

Claims (6)

  An introducing step of introducing a composite fiber intermediate in which resin fibers in the form of a thermoplastic base material resin into fibers and reinforcing fibers are introduced into the mold, and the introduced composite fiber intermediate in the mold A heating step in which the resin fiber is melted by heating, and a solidification step in which the composite fiber intermediate that has undergone the heating step is continuously drawn out from the molding die and cooled to be solidified, and the molding die is used as a base resin. A method for producing a fiber-reinforced resin molded article, wherein the composite fiber intermediate is introduced in a state of being heated to a melting temperature or higher. In the manufacturing method of the fiber reinforced resin molded product of Claim 1,
A method for producing a fiber-reinforced resin molded article, wherein a preheating step is performed in which the composite fiber intermediate is preheated by passing through a preheating chamber in which hot air is generated before the introducing step. In the manufacturing method of the fiber reinforced resin molded product of Claim 1 or 2,
The method for producing a fiber-reinforced resin molded article, wherein the composite fiber intermediate contains resin fibers and reinforcing fibers in different proportions. In the manufacturing method of the fiber reinforced resin molded product of Claim 3,
The method for producing a fiber-reinforced resin molded product, wherein the resin fibers are arranged at a high content ratio along the inner peripheral surface of the passage of the molding die. In the manufacturing method of the fiber reinforced resin molded product according to any one of claims 1 to 4,
A method for producing a fiber-reinforced resin molded product, wherein the base material resin is a crystalline resin having a predetermined softening temperature. In the manufacturing method of the fiber reinforced resin molded product according to any one of claims 1 to 5,
The method for producing a fiber-reinforced resin molded product, wherein the molding die has an opening area at a mold inlet larger than an opening area at a mold outlet.

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