JP2016179598A - Method for molding molded body formed of fiber-reinforced thermoplastic resin - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for molding a molded body formed of a fiber-reinforced thermoplastic resin with a simple facility.SOLUTION: A method for molding a molded body formed of a fiber-reinforced thermoplastic resin includes: a step of arranging a fiber-reinforced thermoplastic resin on a single-sided mold; a step of stacking a planer heating element on the fiber-reinforced thermoplastic resin; a step of covering the molded body and the planer heating element with a heat resistant bagging material, and sealing them with a heat resistant sealing material; a step of discharging air between the heat resistant bagging material and the single-sided mold to attain a vacuum state; a step of heating the fiber-reinforced thermoplastic resin with the planer heating element; and a step of cooling the fiber-reinforced thermoplastic resin after the lapse of a fixed time.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method capable of molding an automotive part made of, for example, a fiber reinforced thermoplastic resin with simple equipment.

  In recent years, application of fiber-reinforced composite materials to structural parts such as automobiles has been actively studied. For example, bonnet parts and roof parts of automobiles are molded by molding methods such as autoclave molding and resin transfer molding using fiber reinforced thermosetting resins such as carbon fiber composite materials.

  However, these molding methods take a long time to cure the resin, so the molding time is long. Therefore, these molding methods have been applied to parts for racing cars and supercars that are produced in small quantities, even among automobile parts. It is difficult to apply to parts for mass-produced vehicles that produce tens of thousands or more because of the high molding cost.

  In addition, since fiber reinforced thermosetting resin is difficult to return to the state of resin before molding once cured, there are many problems to apply to parts for mass production vehicles from the viewpoint of material recyclability. This is the actual situation.

  Therefore, in order to solve these problems, studies are being made on a molded body using a fiber-reinforced thermoplastic resin that has a short molding time and is easy to recycle, and a molding method thereof.

  For example, by laminating a fiber reinforced thermoplastic composite material on a male or female open mold, covering the entire open mold with a heat-resistant bag material, and then discharging the air between the bag material and the open mold, the bag A heating vacuum bag forming method has been proposed in which a fiber-reinforced thermoplastic composite material is heated and molded in a state in which the fiber-reinforced thermoplastic composite material is in close contact with the open mold (see Patent Document 1).

  However, it is not easy to cover the entire open mold with a heat-resistant bag material in the case of a large molded body such as an automobile part. Furthermore, when a hot air circulation oven is used as a heating source, it is necessary to prepare the oven in accordance with the size and quantity of the molded body, resulting in a high cost. In addition, when an electric heater provided in an open mold is used as a heating source, there is a problem that an equipment cost for rapidly raising and lowering the temperature of the mold so as to satisfy a predetermined temperature condition is required.

  On the other hand, it has also been proposed to use a flexible sheet heating element as a heating source, and it is possible to form the sheet relatively easily. However, the sheet heating element is a surface opposite to the open mold of the bag material. Therefore, there is a problem that the bag material becomes a heat insulating material and a predetermined temperature condition cannot be obtained. Further, when the molded body has a complicated shape, the planar heating element is simply installed on the surface of the bag material opposite to the open mold, so that the gap between the planar heating element and the molded body There is a problem that gaps are easily generated and temperature spots are generated.

JP 2004-276471 A

  Accordingly, an object of the present invention is to provide a method capable of molding a molded body made of a fiber-reinforced thermoplastic resin with simple equipment in order to eliminate the above-described problems in the prior art.

  In order to solve the above-described problems, a molding method for a molded body made of a fiber-reinforced thermoplastic resin according to the present invention includes a step of placing a fiber-reinforced thermoplastic resin on a single-sided mold, A step of stacking a sheet heating element on the sheet, a step of covering the molded body and the sheet heating element with a heat-resistant bagging material and sealing with a heat-resistant sealing material, and between the heat-resistant bagging material and the single-sided mold The method comprises the steps of: exhausting the air to form a vacuum; heating the fiber reinforced thermoplastic resin with the planar heating element; and cooling after a lapse of a predetermined time. .

  In such a molding method for a molded article made of a fiber reinforced thermoplastic resin according to the present invention, a sheet heating element is stacked on the fiber reinforced thermoplastic resin, and the molded article and the sheet heating element are heat resistant together. The fiber-reinforced thermoplastic resin can be set to a predetermined temperature condition because it is covered with the conductive bagging material. Furthermore, even if the molded product has a complicated shape, the fiber reinforced thermoplastic resin and the planar heating element are closely adhered to the single-sided mold, so that temperature spots are less likely to occur, and a high-quality molded product with high dimensional accuracy. Can be obtained.

  In the method for molding a molded body made of the fiber reinforced thermoplastic resin according to the present invention, it is preferable that the single-sided material is formed of a heat insulating material because heat from the planar heating element is hardly lost.

  In the method for molding a molded body made of the fiber-reinforced thermoplastic resin according to the present invention, the planar heating element is formed of a material having flexibility, even if the molded body has a complicated shape. However, since it can deform | transform according to the shape and it is hard to produce a temperature spot, it is preferable. Although it will not specifically limit if it is a material which has a flexibility, Silicon rubber etc. which do not need to carry out a mold release process when making it closely_contact | adhere to a fiber reinforced thermoplastic resin are mentioned.

  In the method for forming a molded body made of the fiber-reinforced thermoplastic resin according to the present invention, the form of the reinforcing fiber is not particularly limited, and unidirectional continuous fibers, woven fabrics, discontinuous mats, or a combination thereof can be used. In the present invention, a sheet heating element is overlaid on a fiber reinforced thermoplastic resin, the molded body and the sheet heating element are covered together with a heat resistant bagging material, and sealed with a heat resistant sealing material. Since the air between the single-sided mold and the single-sided mold is in a vacuum state, since it is in a pressurized state from all directions, the molten thermoplastic resin hardly flows out even if heated to the melting point of the thermoplastic resin, Reinforcing fibers are also less disturbed. Therefore, in general, it can be suitably used for unidirectional continuous fibers that tend to cause fiber disturbance.

  Further, in the molding method of the molded article made of the fiber reinforced thermoplastic resin according to the present invention, the reinforcing fiber is not particularly limited, and carbon fiber, glass fiber, aramid fiber, or the like, or a combination thereof can be used. It is preferable to use carbon fiber from the viewpoint of realizing the light weight, high strength and high rigidity performance required for the above.

  Further, in the molding method of the molded body comprising the fiber-reinforced thermoplastic resin according to the present invention, the thermoplastic resin is not particularly limited, but from the viewpoint of strength, rigidity, and heat resistance required for automotive parts, a polyamide-based material is used. A resin is preferred.

  As described above, according to the molding method of the molded body made of the fiber reinforced thermoplastic resin according to the present invention, it is possible to mold relatively easily and at low cost without the necessity of preparing a large facility such as a hot air circulation oven. Moreover, even a molded body having a complicated shape can be molded with high dimensional accuracy and high quality. Furthermore, since the thermoplastic resin is used, the molding time can be shortened as compared with the thermosetting resin, and the recyclability is excellent, so that it is suitable for, for example, mass production of automobile parts.

It is a schematic sectional drawing which shows the manufacturing apparatus of the molded object which consists of a fiber reinforced thermoplastic resin which concerns on one embodiment of this invention. It is a schematic sectional drawing which shows the manufacturing apparatus of the molded object which consists of the conventional fiber reinforced thermoplastic resin.

  Embodiments of the present invention will be described below in comparison with the prior art with reference to the drawings.

  FIG. 1: has shown schematic sectional drawing which shows the manufacturing apparatus 1 of the molded object which consists of the fiber reinforced thermoplastic resin 2 which concerns on one embodiment of this invention. In this embodiment, the fiber reinforced thermoplastic resin 2 is placed on a single-sided mold 4 placed on a work table 3, and the sheet heating element 5 is stacked on the fiber reinforced thermoplastic resin 2, so that a heat resistant bagging material is provided. 6 is covered with a heat-resistant sealing material 7, and air in a space surrounded by the heat-resistant bagging material 6, the single-sided mold 4 and the work table 3 is discharged by a vacuum pump 8 to be in a vacuum state. It shows a molding method in which heating is carried out and cooling is carried out after a certain period of time.

  Here, the vacuum state may be such that the fiber-reinforced thermoplastic resin 2 and the planar heating element 5 can be in close contact with the single-sided mold 4 by the heat-resistant bagging material 6, and may be a low vacuum state of 100 to 100 kPa.

  The heating temperature is preferably adjusted within the range from (Tm−10) ° C. to (Tm + 10) ° C. with respect to the melting point Tm (° C.) of the thermoplastic resin used for the fiber reinforced thermoplastic resin 2. When the temperature is lower than (Tm-10) ° C., the thermoplastic resin is not sufficiently melted, so that the dimensional accuracy of the molded body made of the fiber-reinforced thermoplastic resin 2 is deteriorated. On the other hand, when the temperature is higher than (Tm + 10) ° C., the viscosity of the molten thermoplastic resin becomes too low, and the thermoplastic resin tends to flow, and there is a possibility that resin burrs are frequently generated. When the temperature at the time of heating is adjusted within the range of (Tm−10) ° C. to Tm, it is in a molten state sufficient to ensure the dimensional accuracy of the molded body made of the fiber reinforced thermoplastic resin 2, and the resin burr is removed. Since it can also suppress, it is more preferable. Then, after maintaining for a certain period of time at the above temperature to ensure the required dimensional accuracy, the mold is easily removed when the temperature is lowered to near the glass transition temperature Tg of the thermoplastic resin.

  The heat-resistant bagging material 6 and the heat-resistant sealing material 7 are preferably made of a material having heat resistance enough to withstand the melting point Tm (° C.) of the thermoplastic resin used for the fiber-reinforced thermoplastic resin 2. For example, silicon-based, synthetic rubber-based and fluorine-based ones can be mentioned.

  The single-sided mold 4 is preferably formed of a heat insulating material because heat from the planar heating element 5 is hardly taken away. Although a material will not be specifically limited if it is a heat insulation material, From a viewpoint of availability or machinability, a wood material, a gypsum material, a resin material etc. are mentioned. Moreover, it is preferable that the surface of the single-sided mold 4 is subjected to a mold release treatment so that the molded body can be easily removed. Further, a trim line marking may be provided to facilitate post-processing.

  The planar heating element 5 is made of a material having flexibility such as silicon rubber, for example. Even when the molded body has a complicated shape, the planar heating element 5 can be deformed in accordance with the shape, so that temperature spots are also generated. It is difficult and preferable. Further, the heat transfer wire used for the planar heating element 5 may be a general nichrome wire or a heat transfer wire using high-strength carbon fibers. Carbon fiber is preferable because it has a large heat capacity compared to a metal-based material such as steel and thus hardly fluctuates with respect to the set temperature.

  The form of the reinforcing fiber used for the fiber reinforced thermoplastic resin 2 is not particularly limited, and unidirectional continuous fiber, woven fabric, discontinuous mat, or a combination thereof can be used, but according to the molding method of the present invention, Since the reinforcing fiber is not easily disturbed even when heated to the melting point Tm of the thermoplastic resin, it can be suitably used for a unidirectional continuous fiber that is likely to cause fiber disturbance.

  Carbon fiber, glass fiber, aramid fiber, or a combination of these can be used as the reinforcing fiber used in the fiber reinforced thermoplastic resin 2, but the lightweight, high strength and high rigidity performance required for automotive parts has been achieved. It is preferable to use carbon fiber from the viewpoint that can be achieved.

  In addition, the resin used for the fiber reinforced thermoplastic resin 2 is preferably a polyamide-based resin from the viewpoint of strength, rigidity, and heat resistance required for automotive parts, but is particularly limited if it is a thermoplastic resin. Not.

  On the other hand, FIG. 2 is a schematic cross-sectional view showing a manufacturing apparatus 11 for a molded body made of a fiber reinforced thermoplastic resin 12 according to the prior art, in which the planar heating element 15 is opposite to the open mold 14 of the bag material 16. Therefore, the bag material 16 becomes a heat insulating material, resulting in a problem that a predetermined temperature state cannot be obtained.

  Furthermore, when the molded body made of the fiber reinforced thermoplastic resin 12 has a complicated shape, the planar heating element 15 is simply disposed on the surface opposite to the open mold 14 of the bag material 16. A gap is likely to occur between the sheet heating element 15 and the fiber reinforced thermoplastic resin 12, and temperature spots are generated.

  The above-mentioned embodiment is an illustration to the last, Comprising: This invention includes all the structures described in the claim.

  The molding method of the molded body made of the fiber reinforced thermoplastic resin according to the present invention can be applied to all automobile parts aimed at weight reduction and the like, and can be applied to large parts for aircraft and ships with inexpensive equipment, It is also suitable for parts for electronic devices such as notebook personal computer cases.

DESCRIPTION OF SYMBOLS 1,11 Manufacturing apparatus 2,12 Fiber reinforced thermoplastic resin 3 Work table 4,14 Single-sided type | mold 5,15 Planar heating element 6,16 Heat resistant bagging material 7,17 Heat resistant sealing material 8,18 Vacuum pump

Claims (6)

  A method for forming a molded body made of a fiber reinforced thermoplastic resin, the step of placing the fiber reinforced thermoplastic resin on a single-sided mold, and the step of stacking a planar heating element on the fiber reinforced thermoplastic resin; A step of covering the molded body and the sheet heating element with a heat-resistant bagging material and sealing with a heat-resistant sealing material; and discharging the air between the heat-resistant bagging material and the single-sided mold into a vacuum state Forming a molded body made of a fiber-reinforced thermoplastic resin, comprising: a step of heating the fiber-reinforced thermoplastic resin with the planar heating element; and a step of cooling after a predetermined time has elapsed. Method.   The molding method for a molded body made of a fiber reinforced resin according to claim 1, wherein the single-sided mold is formed of a heat insulating material.   The molding method for a molded body made of a fiber-reinforced resin according to claim 1, wherein the planar heating element is made of a flexible material.   The shaping | molding method of the molded object sheet | seat which consists of a fiber reinforced resin in any one of Claim 1 to 3 whose form of the said fiber is a unidirectional continuous fiber.   The shaping | molding method of the molded object which consists of fiber reinforced resin in any one of Claim 1 to 4 whose said fiber is carbon fiber.   The molding method of the molded object which consists of a fiber reinforced resin in any one of Claims 1-5 whose said resin is a polyamide-type resin.

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