JP2009179001A - Hollow member for molding - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the pressure-proof properties and contraction resistance of a hollow member for molding. <P>SOLUTION: The hollow member 1 for molding which is used for heating/pressurization molding a hollow fiber-reinforced plastic molding has a hollow body 3 made of silicone rubber and a fabric 5 embedded in the hollow body 3. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a molding hollow member used for heating and pressure molding of a fiber-reinforced plastic hollow molded article.

  Conventionally, it is known to heat and pressure-mold a fiber-reinforced plastic molded product.

In the thing of patent document 1, after laying a prepreg along the inner surface of the type | mold which has a type | mold main body and a protrusion type | mold whose volume is smaller than this type | mold main body, it arrange | positions a foam sheet on the prepreg laid in the protrusion type | mold Next, an internal mold having substantially the same shape as the internal space of the protruding mold is placed inside the protruding mold via a prepreg and a foam sheet, and an inflatable bag is placed inside the prepreg laid on the mold main body. A prepreg is pressurized by filling a bag with a fluid, and then a foamed sheet is foamed by heating and the prepreg is cured to produce a fiber-reinforced plastic hollow molded article.
Japanese Patent Laying-Open No. 2005-161701

  By the way, the present inventors have developed a silicone rubber molding hollow member 101 as shown in FIG. 11, which is used for heating and pressure-molding a fiber-reinforced plastic hollow molding product. The molding hollow member 101 is formed of a silicone rubber hollow body 103 having a rectangular cross-sectional shape.

  When heating and pressure-molding a hollow molded product using the molding hollow member 101, first, a plastic resin, a fiber, and a plastic resin (not shown) are wound around the molding hollow member 101 in this order, and By laminating these plastic resins and fibers in layers, the fibers and resin are laminated to form a prepreg, and then the laminated prepreg is wound around the hollow molding member 101 and cured by applying a predetermined heat under a predetermined pressure. Then, the molding hollow member 101 is extracted from the cured prepreg. As described above, a hollow molded product having a rectangular cross section is completed.

  Thus, when molding a hollow molded product using the molding hollow member, pressure is applied to the molding hollow member, so pressure resistance is required for the molding hollow member. Since it consists only of silicone rubber, pressure resistance is not sufficient.

  Further, since the molding hollow member 101 is made of silicone rubber, it extends during the hot molding of the hollow molded product, but shrinks when cooled. Therefore, when the molding hollow member 101 is repeatedly used, a hollow molded product of a predetermined size is molded. Therefore, the dimension in the longitudinal direction of the molding hollow member 101 required for the above is insufficient.

  This invention is made | formed in view of this point, The place made into the objective is to provide the technique which improves the pressure | voltage resistance and shrinkage resistance of the hollow member for shaping | molding.

  1st invention is a hollow member for shaping | molding used for heating and press-molding the fiber reinforced plastic hollow molded product, Comprising: The silicone rubber hollow body and the woven fabric embedded in the said hollow body It is characterized by having.

  Thus, since the strength of the hollow member for molding is increased by embedding the woven fabric in the hollow body, the pressure resistance and shrinkage resistance of the hollow member for molding can be improved. Therefore, when a hollow molded product is heated and pressure-molded using the molding hollow member, the molding hollow member can be prevented from being ruptured (partially broken), and the molding hollow member is repeatedly heated and pressurized. Even when used for molding, shrinkage of the molding hollow member can be suppressed.

  In a second aspect based on the first aspect, the hollow body has an inner layer and an outer layer provided on the outer side of the inner layer and having a thickness substantially the same as the inner layer. , Between the inner layer and the outer layer.

  In this way, the hollow body is provided on the inner layer and on the outer side of the inner layer, has an outer layer that is substantially the same as the inner layer, and the woven fabric is disposed between the inner layer and the outer layer. Therefore, the woven fabric is too close to the inside of the hollow body and the strength of the outside of the hollow member for molding is reduced, or the woven fabric is too close to the outside of the hollow body and the mesh of the woven fabric is transferred to the surface of the hollow molded product. Can be suppressed.

  According to a third invention, in the first or second invention, the woven fabric is made of polyester fiber.

  Thus, by using the polyester fiber excellent in heat resistance, shrinkage resistance, etc., the pressure resistance and shrinkage resistance of the molding hollow member can be further improved.

  In the present invention, the woven fabric means a woven fabric in which the strength in at least two directions orthogonal to each other is improved by knitting the fibers, such as a woven fabric obtained by crossing warp and weft at right angles. The fibers include synthetic resin fibers, metal fibers, glass fibers, carbon fibers and the like.

  The fiber reinforced plastic is a material reinforced and reduced in weight by dispersing glass fiber or carbon fiber in the plastic.

  According to the present invention, by embedding a woven fabric in a silicone rubber hollow body, the pressure resistance and shrinkage resistance of the molding hollow member can be improved. When heating / pressing molding, the molding hollow member can be prevented from rupturing, and even when the molding hollow member is repeatedly used for heating / pressing molding, the molding hollow member is prevented from shrinking. be able to.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

-Configuration of molding hollow member-
1 and 2 show an example of the molding hollow member of the present invention. A molding hollow member (molding bladder) 1 is used for autoclave molding of a hollow molded product made of fiber reinforced plastic (hereinafter referred to as FRP) such as a hollow pipe or a hollow frame, and has a rectangular cross section. A silicone rubber hollow body 3 having a closed cross-sectional shape and a polyester fiber woven fabric 5 embedded in substantially the entire hollow body 3 are provided. In FIG. 1, the woven fabric 5 is shown as a white layer for easy viewing, and the thicknesses of the rubber layers 13 and 23 and the woven fabric layer 5 are exaggerated. The same applies to other drawings. And

  The hollow body 3 includes an inner rubber layer (inner layer) 13 and an outer rubber layer (outer layer) 23 that is provided on the outer side of the inner rubber layer 13 and has substantially the same thickness as the inner rubber layer 13. Yes. Silicone rubber is excellent in heat resistance, chemical resistance, water repellency, electrical insulation, and the like.

  The woven fabric 5 is knitted with warps 15 and wefts 25 crossed at right angles (arranged perpendicularly to each other). The warp 15 extends in the longitudinal direction of the hollow body 3 and the wefts 25. It arrange | positions between the inner side rubber layer 13 and the outer side rubber layer 23 so that the weft direction which extends may respectively correspond with the circumferential direction of the hollow body 3, and the outer peripheral surface and outer side of the inner side rubber layer 13 over the perimeter. The rubber layer 23 is integrally formed with the inner peripheral surface. The woven fabric 5 is embedded between the inner rubber layer 13 and the outer rubber layer 23 in this manner, so that the woven fabric 5 is embedded in a substantially central portion of the hollow body 3 in the thickness direction. Polyester has excellent heat resistance since its melting point exceeds 250 degrees, and also has excellent shrinkage resistance and tensile strength.

  Further, the molding hollow member 1 is made of polyester and silicone rubber having excellent heat resistance as described above, and thus has heat resistance that can withstand the heating temperature (about 180 degrees) during autoclave molding of hollow molded products. ing.

-Manufacturing method of hollow member for molding-
FIG. 3 is a schematic view for explaining a production method for molding a rubber sheet from a silicone rubber material. In FIG. 3, reference numerals 7a and 7b are first and second kneading rolls for rolling the silicone rubber material 21 into a sheet shape, and reference numeral 9 is a conveyor for continuously conveying the rubber sheet 33 and the like being molded. Reference numeral 11a denotes a first supply roll for supplying the adhesion-preventing sheet 27 onto the conveyor 9, and reference numerals 17a and 17b denote first and second pressing rolls for pressing the conveyed semi-finished product from above and below on the conveyor 9, and reference numeral 19a Is the first winding roll.

  The silicone rubber material 21 is supplied from above between the first kneading roll 7 a and the second kneading roll 7 b, rolled between the both rolls 7 a and 7 b to become a rubber sheet 33, and supplied onto the conveyor 9. At this time, the rubber sheet 33 is conveyed in a state of being stacked on the adhesion-preventing sheet 27 supplied onto the conveyor 9 from the first supply roll 11a. Next, the rubber sheet 33 overlapped with the deposition sheet 27 is supplied between the first pressing roll 17a and the second pressing roll 17b, and is pressed from above and below by these rolls 17a and 17b. It is integrated with the rubber sheet 33. Thus, the rubber sheet 33 integrated with the deposition preventing sheet 27 is wound up by the first winding roll 19a.

  FIG. 4 is a schematic view illustrating a manufacturing method for forming a woven fabric-containing rubber sheet. In FIG. 4, reference numerals 11 b and 11 c are second and third supply rolls for supplying rubber sheets 33 and 33 onto the conveyor 9, respectively, and reference numeral 11 d is a fourth supply roll for supplying the woven fabric 5 onto the conveyor 9. Yes, reference numerals 29a and 29b are topping rolls that press and integrate a plurality of stacked sheets from above and below, and reference numeral 19b is a second winding roll.

  Two rubber sheets 33 molded as described above are prepared and set on the second supply roll 11b and the third supply roll 11c, respectively. When the second supply roll 11b rotates counterclockwise in FIG. 4, the rubber sheet 33 is supplied onto the conveyor 9 with the adhesion preventing sheet 27 on the upper side, while the third supply roll 11c is in the timepiece of FIG. When rotating around, the rubber sheet 33 is supplied onto the conveyor 9 with the adhesion-preventing sheet 27 on the lower side. At this time, the woven fabric 5 made of polyester fiber supplied from the fourth supply roll 11d is overlaid on the upper surface of the rubber sheet 33 supplied from the third supply roll 11c, and the second supply is further applied to the upper surface of the woven fabric 5. The rubber sheet 33 supplied from the roll 11b is stacked. Next, the two upper and lower rubber sheets 33, 33 are supplied between the first topping roll 29a and the second topping roll 29b with the woven fabric 5 sandwiched therebetween, and these rolls 29a, 29b are supplied. Is pressed from above and below. Thereby, the rubber sheet 43 with a woven fabric in which the woven fabric 5 is embedded between the two rubber sheets 33 is formed. The rubber sheet 43 with the woven fabric is wound up by the second winding roll 19b.

  The long woven fabric-containing rubber sheet 43 obtained in this way is cut in accordance with the circumferential length of a core (core bar, mandrel) 31 (see FIG. 6) having a rectangular cross-sectional shape. Specifically, as shown in FIG. 6, when the woven fabric rubber sheet 43 is wound around the core 31, the wrap portion 35 is formed by overlapping both ends 43 a and 43 b in the winding direction of the woven fabric rubber sheet 43. As described above, the rubber sheet 43 with the woven fabric is cut to a length obtained by adding 2 cm (the length in the winding direction of the wrap portion 35) to the circumferential length of the core 31.

  Next, as shown in FIG. 5 (a), in the cut rubber sheet 43 with woven fabric, the left end (one end in the winding direction) 35a of the lower (one) rubber sheet 33a in FIG. The right side end portion (the other end portion in the winding direction) 35b of the upper (other side) rubber sheet 33b is removed. Specifically, a portion 35 a of 2 cm from the left end of the lower rubber sheet 33 a that is outside the woven fabric 5 when wound around the core 31, and the woven fabric 5 when wound around the core 31. The 2 cm portion 35b is scraped off and removed from the right end of the upper rubber sheet 33b which is the inner side. By removing the silicone rubbers 35a and 35b in this manner, the woven fabric 5 at both ends 43a and 43b in the winding direction of the rubber sheet with the woven fabric is exposed as shown in FIG. 5B.

  Then, as shown in FIG. 6A, the core 31 is placed at a substantially central portion on the upper surface of the woven fabric rubber sheet 43, and the woven fabric rubber sheet 43 is wound so as to cover the side surface of the core 31. It is done. Next, as shown in FIG. 6 (b), the left end 43a of the rubber sheet 43 with woven fabric is placed on the upper surface of the core 31 so that the exposed woven fabric 5a is on the upper side. And as shown in FIG.6 (c), the right side edge part 43b of the rubber sheet 43 with a woven fabric is covered on the upper surface of the core 31 so that the exposed woven fabric 5b may become a lower side. In this way, the wrap portion 35 is formed by winding the woven fabric-containing rubber sheet 43 around the core 31 so that the exposed woven fabrics 5a and 5b of both ends 43a and 43b in the winding direction are in contact with each other and overlap each other. The

  When the winding of the woven fabric rubber sheet 43 around the core 31 is completed, the upper die 37 and the lower die 39 are wound with the woven fabric rubber sheet 43 wound around the core 31, as shown in FIG. The hollow body 3 is vulcanized and molded by being heated and pressurized using a thermoforming press (not shown). Then, as shown in FIG. 7B, the upper die 37 and the lower die 39 are opened, and the core 31 is extracted from the vulcanized hollow body 3. Thereafter, the hollow body 3 in which the woven fabric 5 is embedded is placed in a secondary vulcanization furnace (not shown) and subjected to secondary vulcanization (reheating) in order to stabilize the characteristics of the silicone rubber. . As described above, the molding hollow member 1 having a rectangular outer cross-sectional shape is completed.

  As described above, the hollow body 3 is not extruded and vulcanized and molded by heating and pressurizing the rubber sheet 43 with a woven fabric around the core 31 for the following reason. That is, in order to improve pressure resistance and shrinkage resistance, it is considered that the woven fabric 5 is embedded in the hollow body 3 when the hollow body 3 is extruded, but the silicone rubber at the time of extrusion molding is very soft. Therefore, it is difficult to braid the fibers against the silicone rubber, and when the fibers are braided against the silicone rubber having a hollow portion, the balance of the fiber tightening force is maintained especially when the cross-sectional shape is other than circular. Otherwise, the shape may be crushed. On the other hand, if the hollow body 3 is vulcanized and molded by heating and pressurizing the rubber sheet 43 with woven fabric around the core 31, it is not necessary to braid the fibers when molding the hollow body 3. This is because the hollow body 3 having various cross-sectional shapes in which the woven fabric 5 is embedded can be formed.

  Further, by removing the left end 35a of the lower rubber sheet 33a and the right end 35b of the upper rubber sheet 33b in the woven fabric rubber sheet 43, both ends in the winding direction of the woven fabric rubber sheet 43 are removed. The reason why the woven fabric 5 of the portions 43a and 43b is exposed and wound around the core 31 so that the exposed woven fabrics 5a and 5b are in contact with each other to form the wrap portion 35 is as follows. That is, if the wrap portion 35 is formed by overlapping both end portions 43a and 43b of the woven fabric rubber sheet 43, the pressure resistance of the molding hollow member 1 can be increased, but the silicone rubbers 35a and 35b are not removed. If both end portions 43a and 43b of the woven fabric-containing rubber sheet 43 are overlapped, excess silicone rubber 35a and 35b are present in the wrap portion 35 as shown in FIG. Is approximately twice the thickness of the portion other than the wrap portion 35. In this state, when heated and pressed by a thermoforming press, excess silicone rubber 35a, 35b melts in the direction of the arrow 41 in the drawing, and the woven fabric 5b at the right end is pushed to the right in the drawing. Will act. As a result, as shown in FIG. 8B, in the wrap portion 35, the woven fabric 5a at the left end and the woven fabric 5b at the right end do not wrap, and the pressure resistance of the molding hollow member 1 is reduced. This is because there is a risk of inviting.

  Hereinafter, an autoclave molding method for FRP hollow molded products using the molding hollow member 1 will be described. First, a plastic resin, a fiber, and a plastic resin are wound around the hollow molding member 1 in this order. Then, by laminating these plastic resins and fibers in layers, the fibers and the resin are laminated into a prepreg. Then, the laminated prepreg is put in an autoclave (pressure vessel) in a state of being wound around the molding hollow member 1 and cured by applying a predetermined heat under a predetermined pressure. At this time, since pressure is applied to the prepreg from both the outer side and the inner side, it is possible to make a hollow molded product in which each surface portion extends straight. Thereafter, the cured prepreg is taken out from the autoclave, and the molding hollow member 1 is taken out. Here, since the forming hollow member 1 has flexibility and flexibility by adopting the above-described configuration, the forming hollow member 1 can be easily pulled out from the prepreg. As described above, a hollow molded product having a rectangular closed cross-sectional shape is obtained.

-Effect-
According to this embodiment, since the strength of the molding hollow member 1 is increased by embedding the woven fabric 5 in the silicone rubber hollow body 3, the pressure resistance and shrinkage resistance of the molding hollow member 1 are improved. Can be made. Accordingly, when the hollow molding product 1 is heated and pressure-molded using the molding hollow member 1, the molding hollow member 1 can be prevented from bursting, and the molding hollow member 1 can be repeatedly heated and pressurized. Even when it is used, it is possible to prevent the molding hollow member 1 from shrinking.

  The hollow body 3 includes an inner rubber layer 13 and an outer rubber layer 23 having a thickness substantially the same as that of the inner rubber layer 13. Since it is disposed between the rubber layer 13 and the outer rubber layer 23, the woven fabric 5 is too close to the inner side of the hollow body 3, and the strength of the outer side of the molding hollow member 1 is reduced. It is possible to prevent the mesh of the woven fabric 5 from being transferred (raised) to the surface of the FRP hollow molded product too close to the outside of the hollow body 3.

  Furthermore, the pressure resistance and shrinkage resistance of the molding hollow member 1 can be further improved by using polyester fibers that are excellent in heat resistance and shrinkage resistance.

(Other embodiments)
In the said embodiment, although the hollow member 1 for shaping | molding is used for carrying out the autoclave shaping | molding of the FRP hollow shaping | molding goods, you may use it for heating and press-molding other than autoclave shaping | molding.

  Moreover, in the said embodiment, although the woven fabric 5 made from a polyester fiber is used, the material of the woven fabric 5 is not restricted to a polyester fiber, For example, synthetic resin fibers, such as a nylon fiber and an aramid fiber, or a metal fiber, glass Fibers and carbon fibers may be used.

  Furthermore, in the above embodiment, the woven fabric 5 used is a knitted fabric obtained by crossing the warp yarn 15 and the weft yarn 25. However, as long as the woven fabric has improved strength at least in two orthogonal directions, the configuration is It is not restricted to the above.

  Moreover, in the said embodiment, although the rolled rubber sheet and the adhesion prevention sheet 27 are integrated, you may apply | coat an adhesion prevention agent etc. on the surface of a rubber sheet, for example.

  Furthermore, in the above embodiment, when the woven fabric rubber sheet 43 is wound around the core 31, the wrap portion 35 is formed by overlapping the winding direction end portions 43 a and 43 b of the woven fabric rubber sheet 43. However, the wrap portion 35 may not be formed.

  Moreover, in the said embodiment, although the cross-sectional shape of the silicone rubber hollow body 3 is made into the rectangular shape, it is not restricted to this, For example, according to the cross-sectional shape of a hollow molded product, circular shape or an elliptical shape (FIG. Non-circular shape such as 9 (see FIG. 9B), or a rectangle other than a rectangle such as a triangle (see FIG. 9B), a square (see FIG. 9C), a trapezoid (see FIG. 9D), Polygonal shapes such as a pentagon (see FIG. 9E), a hexagon (see FIG. 9F), and an octagon (see FIG. 9G) may be used.

  The present invention is not limited to the embodiments, and can be implemented in various other forms without departing from the spirit or main features thereof.

  As described above, the above-described embodiment is merely an example in all respects and should not be interpreted in a limited manner. Further, all modifications and changes belonging to the equivalent scope of the claims are within the scope of the present invention.

  In order to confirm the effects of the present invention, the following tests were conducted to evaluate the pressure resistance and shrinkage resistance of the molding hollow member.

<Test product>
In each of Example 1, Example 2, Example 3, and Comparative Example, a molding hollow member comprising a silicone rubber hollow body made of silicone rubber having a rubber hardness of 80 degrees and having a rectangular cross-sectional shape was used. Further, in Example 1, Example 2 and Example 3, the hollow body is provided with a fiber having a thickness of 275 T (decitex) in the longitudinal direction of the hollow body at 24 / Inch, and in the circumferential direction of the hollow body at 25 / What embedded the woven fabric arrange | positioned mutually orthogonally by Inch was used. As materials for the woven fabric, aramid fibers were used in Example 1, polyester fibers were used in Example 2, and nylon fibers were used in Example 3. In contrast, in the comparative example, no woven fabric was embedded in the hollow body.

<Test>
The molding hollow member was placed in a pressure vessel, and the internal pressure of the pressure vessel was gradually increased, and the internal pressure (burst pressure) of the pressure vessel when the molding hollow member burst (partially broken) was measured.

  In addition, the molding hollow member is placed in a heating furnace, heated for 2 hours at 180 °, which is substantially the same as the heating temperature at the time of autoclave molding of the hollow molded product, and then naturally cooled to one cycle, which is repeated 30 cycles. At each cycle end, the contraction rate in the longitudinal direction with respect to the molding hollow member before the test was measured.

  <Test results>

  As shown in Table 1, in Example 1 using aramid fibers, the molding hollow member burst when the internal pressure of the pressure vessel is 1.00 MPa, which is five times the burst pressure (0.20 MPa) of the comparative example. In Example 2 using polyester fibers, the molding hollow member burst when the internal pressure of the pressure vessel was 0.60 MPa, which is three times the burst pressure of the comparative example. Further, in Example 3 using nylon fibers, the hollow member for molding burst at the lowest internal pressure among the Examples, but the burst pressure was 0.38 MPa corresponding to about twice the burst pressure of the comparative example. .

  On the other hand, with respect to shrinkage resistance, as shown in FIG. 10, Example 2 using polyester fibers showed the best results, and then Example 3 using nylon fibers showed a remarkable effect. On the other hand, in Example 1 using an aramid fiber, the increase in shrinkage was remarkable compared to Example 2 and Example 3 since the number of cycles exceeded 5 times, but a woven fabric was embedded. The shrinkage resistance was higher than that of the comparative example.

  From the above results, it was confirmed that the pressure resistance and the shrinkage resistance of the molding hollow member were improved by embedding the woven fabric in the hollow body. Particularly, in Example 2 using a molding hollow member in which a polyester fiber woven fabric was embedded, good results were obtained in both pressure resistance and shrinkage resistance.

  As described above, the present invention is useful for a hollow molding member used for heating and pressure molding a FRP hollow molded article.

1 is a schematic cross-sectional view of a molding hollow member according to the present invention. It is a schematic perspective view of the hollow member for shaping | molding. It is the schematic explaining the manufacturing method which shape | molds a rubber sheet from a silicone rubber material. It is the schematic explaining the manufacturing method which shape | molds the rubber sheet containing a woven fabric. It is a figure which shows the rubber sheet containing a woven fabric, (a) is a schematic longitudinal cross-sectional view, (b) is a schematic perspective view. It is a schematic cross-sectional view explaining stepwise the method of winding a woven fabric-containing rubber sheet around a core. It is a schematic cross-sectional view explaining the method of shape | molding the hollow body made from a silicone rubber, (a) is a figure which shows a mode that it sandwiched with the upper mold | type and the lower mold in the state which wound the rubber sheet containing a woven fabric around the core (B) is a figure which shows a mode that the upper mold | type and the lower mold | type were opened and the core was extracted from the hollow body. It is a schematic longitudinal cross-sectional view explaining the lap | wrap part formed when the rubber sheet containing a woven fabric is wound around a core, (a) is a figure which shows the state of the lap | wrap part before a heating pressurization, (b (A) is a figure which shows the state of the lap | wrap part after heating-pressing. FIG. 2 is a view corresponding to FIG. 1 showing a modification of the hollow member for molding. It is a graph which shows the shrinkage resistance of the hollow member for shaping | molding. It is a figure which shows the hollow member for shaping | molding, (a) is a schematic cross-sectional view, (b) is a schematic perspective view.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Molding hollow member 3 Silicone rubber hollow body 5 Woven cloth 13 Inner rubber layer (inner layer)
15 Warp (polyester fiber)
23 Outer rubber layer (outer layer)
25 Weft (polyester fiber)

Claims (3)

A hollow member for molding used for heating and pressure molding a hollow molded product made of fiber reinforced plastic,
A silicone rubber hollow body;
A forming hollow member comprising a woven fabric embedded in the hollow body. In the hollow member for molding according to claim 1,
The hollow body has an inner layer and an outer layer that is provided outside the inner layer and has a thickness that is substantially the same as the inner layer.
The hollow member for molding, wherein the woven fabric is disposed between the inner layer and the outer layer. In the hollow member for molding according to claim 1 or 2,
The hollow member for molding, wherein the woven fabric is made of polyester fiber.

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