JP3885848B2 - Composite material molding method and molding die therefor - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a molding method of a composite material and a molding die thereof, and more specifically, molding of a composite material capable of molding a composite material of a resin material with high quality accuracy by a simple direction and mold equipment. The present invention relates to a method and a molding die thereof.
[0002]
[Prior art]
Conventionally, a resin injection molding method (RIM) or a resin transfer molding method (RTM) is a simple resin molding method as a composite material molding method in which a reinforcing fiber base material is impregnated with a matrix resin and molded into a predetermined shape. As a molding method for various parts in addition to molded parts such as vehicle parts.
[0003]
As a resin transfer molding method (RTM), for example, as shown in FIG. 3, it is composed of a lower mold 2 provided with a cavity 1 having a concave cross section and an upper mold 3 fitted to the lower mold 2. After the reinforcing fiber base 4 such as carbon fiber cloth is disposed in the cavity 1, the upper and lower molds 2 and 3 are fitted, and the inside of the cavity 1 is provided by the vacuum suction pipe 5 provided in the upper mold 3. While making the negative pressure state, the matrix resin 7 made of thermosetting resin accommodated in the matrix resin injection machine 6 is press-fitted into the cavity 1 from the resin injection port 2a of the lower mold 2 through the pipe 8, thereby reinforcing the fiber. The base material 4 is impregnated.
[0004]
Thereafter, the matrix resin is heat-cured by heating and pressurizing with heating means (not shown) provided in the upper and lower molds 2 and 3 to form a composite material. Reference numeral 9 denotes a sealing material such as an O-ring.
[0005]
[Problems to be solved by the invention]
By the way, in the resin transfer molding method (RTM) as described above, when molding is performed using a thermosetting resin material such as polyimide resin as a matrix resin, when the resin viscosity at the transfer temperature is extremely high, There has been a problem that the preforms disposed in the cavities 1 and 3 are disturbed by the pressure and viscosity of the matrix resin injected from the resin injection port 2a.
[0006]
In particular, when a two-dimensional or three-dimensional preform that is not firmly fixed in the cavity 1 is used, the internal reinforcing fiber base 4 is disturbed by the resin flow in the vicinity of the resin injection port 2a, resulting in molding. The product is warped and causes non-uniformity such as residual stress, resulting in problems in product accuracy.
As a means for preventing such disturbance of the reinforcing fiber base 4, for example, a method of firmly fixing a three-dimensional preform in the cavity 1 or reducing the transfer speed of the matrix resin can be considered. There is a problem that the advantage as the cost forming method is lost and the productivity cannot be improved.
[0007]
The object of the present invention is to improve the productivity without reducing the transfer speed of the matrix resin, and without causing the product to warp or cause non-uniformity such as residual stress. It is an object of the present invention to provide a molding method of a composite material and a molding die for the molding material that can improve the hardness.
[0008]
[Means for Solving the Problems]
In order to achieve the above-mentioned object, the present invention achieves the above-mentioned object. As a method of molding a composite material, a transmittance using a mesh material whose surface is subjected to a release treatment in a cavity of a lower mold having a resin injection port of a matrix resin. After the adjustment member is placed, the reinforcing fiber base is placed, and the lower die is connected to the lower die by a vacuum suction pipe having a porous filter made of a porous material having a porosity of 40% to 10%. Are closed in a vacuum state by sucking the inside of the cavity through the vacuum suction pipe, and in this state, the matrix resin accommodated in the matrix resin injector is pressurized with pressurized air. The matrix resin is pressed into the reinforcing fiber base from the matrix resin injection port through a permeability adjusting member made of a mesh material having a mesh opening ratio in the cavity of 1 to 80%. At this time, by-products and low-viscosity resin composed of low molecular weight substances generated during the curing reaction of the matrix resin are sequentially removed from the system while being selected by the porous filter, and then impregnated with the matrix resin. The gist is to form a composite material by heating and pressurizing the reinforced fiber base material .
[0009]
Further, the present invention as the molding die of the composite, and a lower mold having a resin injection port of the matrix resin, hermetically fitted to the lower mold, and porosity of 40% to 10% It consists of an upper mold connected to a vacuum suction pipe equipped with a porous filter made of a porous material , and the pressure of the matrix resin to be injected by pressure is uniform on the matrix resin inlet side in the cavity of the lower mold The gist of the invention is that the surface to be impregnated into the reinforcing fiber base is subjected to a release treatment and a transmittance adjusting member made of a mesh material having a mesh opening ratio of 1 to 80% is disposed.
[0010]
Since the present invention is configured as described above, the high-viscosity thermosetting matrix resin injected from the resin injection port of the matrix resin becomes uniform because the permeation pressure is dispersed by the transmittance adjusting member made of a mesh material. Since the thermosetting matrix resin gradually impregnates the reinforcing fiber base in the cavity, the reinforcing fiber base is not disturbed, resulting in improved productivity without reducing the transfer rate of the matrix resin. Therefore, the accuracy of the product can be improved without causing warpage of the molded product or causing non-uniformity such as residual stress.
Further, by- products and low-viscosity resin, which are generated during the curing reaction of the matrix resin, are sequentially removed from the system while being selected by the porous filter, and then the reinforcing fiber base impregnated with the matrix resin is used. By heating and pressurizing the material, it is possible to mold a composite material with high product accuracy.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.
In addition, the same component as a prior art example attaches | subjects the same code | symbol, and abbreviate | omits description.
FIG. 1 shows a cross-sectional view of a molding die used in the composite material molding method of the present invention. The molding die includes a lower die 2 provided with a resin injection port 2a, and a lower die 2. The upper mold 3 is connected to a vacuum suction pipe 5 to be fitted, and a transmittance adjusting member 11 made of a mesh material is disposed horizontally on the resin injection port 2a side of the cavity 1 of the lower mold 2. Has been.
[0012]
The transmittance adjusting member 11 uses a mesh material such as glass cloth coated with polytetrafluoroethylene, and the mesh opening ratio is preferably 1 to 80%. For example, with respect to the injection pressure of 0.1 MPa / cm ² for the matrix resin 7, the permeation pressure is dispersed and made uniform by setting the mesh porosity to about 50%. It is impregnated without disturbing the reinforcing fiber base 4 inside.
[0013]
In addition, using a mesh material having a smaller opening length than the preform bundle diameter ( diameter of the cylindrical body in which the mesh material is bundled) , the releasability from the matrix resin 7 to be used is improved. Therefore, a mesh material whose surface is subjected to a release treatment is used.
The upper and lower molds 2 and 3 are provided with heating means (not shown), and the fitting portion between the lower mold 2 and the upper mold 3 has an O-ring for maintaining watertightness and airtightness in the cavity 1. A sealing material 9 such as is provided.
[0014]
On the transmittance adjusting member 11 disposed in the cavity 1 of the lower mold 2, a reinforcing fiber base 4 such as a carbon fiber cloth or glass fiber is disposed, and a matrix resin is injected into the reinforcing fiber base 4. A matrix resin 7 made of a thermosetting resin such as a highly viscous polyimide resin accommodated in the machine 6 is impregnated through the pipe 8 and the resin injection port 2a. The matrix resin 7 made of this thermosetting resin uses a viscous resin having a resin viscosity of 0.1 Pa.s or more and 1,000 Pa.s or less.
[0015]
The vacuum suction pipe 5 connected to the upper mold 3 is provided with a porous filter 10 made of a porous material such as tetrafluoroethylene, ceramic, graphite, and ultra-high molecular weight polyethylene having air permeability.
For example, in the case of a PTFE porous filter manufactured using polytetrafluoroethylene particles (PTFE particles) having a particle size of 3 microns, the porosity is preferably in the range of 40% to 10%, more preferably 35% to 15%. Range.
[0016]
This is because if the porosity is 40% or more, the resin flow is large and the function as a porous filter is not achieved, and if it is 10% or less, it is difficult to remove low molecular weight substances and the like. In addition, what is necessary is just to select the optimal range suitably about the material of another filter.
Next, a method of molding the composite material while reducing the pressure inside the cavity 1 and conveying the matrix resin 7 will be described with reference to the molding flowchart of FIG.
[0017]
First, at the start, the upper and lower molds 2 and 3 subjected to the mold release treatment are prepared (step {circle around (1)}), and the mesh whose surface is subjected to the mold release process in the vicinity of the resin inlet 2a in the cavity 1 of the lower mold 2 is prepared. The transmittance adjusting member 11 made of a material is disposed horizontally (step {circle around (2)}).
Next, a reinforcing fiber base material 4 such as carbon fiber cloth or glass fiber is disposed on the transmittance adjusting member 11, and a vacuum suction pipe 5 connected to the upper mold 3 includes ethylene tetrafluoride, ceramic, A porous filter 10 made of a porous material such as graphite or breathable ultra-high molecular weight polyethylene is disposed (steps (3) and (4)).
[0018]
Then, the upper mold 3 is airtightly fitted onto the lower mold 2 (step (5)), and the cavity 1 is sucked through a vacuum suction pipe 5 connected to a vacuum pump or the like (not shown). In this state, the pipe 8 and the resin injection port 2a are pressurized while the matrix resin 7 made of thermosetting resin such as highly viscous polyimide resin accommodated in the matrix resin injection machine 6 is pressurized with pressurized air. And press-fit into the cavity 1 (step (6)).
[0019]
The highly viscous matrix resin 7 press-fitted into the cavity 1 is uniformly impregnated into the reinforcing fiber base 4 with the permeation pressure uniformly dispersed by the permeability adjusting member 11 made of a mesh material. As a result, the reinforcing fiber base 4 can be improved in productivity without any fiber disturbance and without reducing the transfer speed of the matrix resin 7.
[0020]
When the matrix fiber 7 is impregnated into the reinforcing fiber base 4, a by-product composed of a low molecular weight substance such as gas, water, alcohol, etc. generated during the curing reaction of the matrix resin 7 or a low viscosity resin is vacuum sucked. While being selected by the porous filter 10 provided on the pipe 5, it is sequentially removed from the system. Thereafter, by molding the composite material by heating and pressurizing with the upper and lower molds 2 and 3, it is possible to manufacture a molded product with high quality accuracy that does not contain voids.
[0021]
When the impregnation operation of the matrix resin 7 is completed as described above, the upper and lower molds 2 and 3 are heated, and the matrix resin 7 is heated and cured to form a composite material (step (8)).
[0022]
When the reinforcing fiber base 4 is impregnated with the matrix resin 7 by the above-described method, the high-viscosity thermosetting matrix resin 7 injected from the matrix resin injection port 2a is a transmittance adjusting member made of a mesh material. 11, the permeation pressure is dispersed and becomes uniform, and this thermosetting matrix resin 7 gradually impregnates the reinforcing fiber base 4 in the cavity 1, so that the reinforcing fiber base 4 is not disturbed. As a result, productivity can be improved without reducing the transfer speed of the matrix resin, and product accuracy can be improved without causing warping of the molded product or non-uniformity such as residual stress. It is possible.
[0023]
Further, since the by-product composed of low molecular weight substances such as gas, water, alcohol, etc. and the mixed solvent are removed from the upper and lower molds 2 and 3, the molded article of the composite material does not contain voids or the like. A molded product with high quality accuracy can be manufactured, and a molding method can be efficiently performed in a short time even if it is not an expert by a simple method using existing equipment.
[0024]
【The invention's effect】
Since the present invention is configured as described above, it is possible to improve productivity without reducing the transfer rate of the matrix resin, causing warping of the molded product, and causing non-uniformity such as residual stress. There is an effect that the product accuracy can be improved without causing it. Further, when using a transmittance adjusting member made of a mesh material subjected to mold release treatment, it is easy to remove the mold from the mold, and workability can be improved.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a molding die used in a composite material molding method of the present invention.
FIG. 2 is a flowchart of a molding process of a composite material according to the present invention.
FIG. 3 is a schematic configuration diagram of a conventional composite material molding apparatus.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Cavity 2 Lower metal mold | die 3 Upper metal mold | die 4 Reinforcement fiber base material 5 Vacuum suction pipe 6 Matrix resin injection machine 7 Matrix resin 8 Piping 9 Sealing material 10 Porous filter 2a Resin injection port 11 Permeability adjustment member

Claims (6)

In the cavity of the lower mold provided with the resin injection port of the matrix resin , after arranging the transmittance adjusting member using the mesh material subjected to the release treatment on the surface, the reinforcing fiber base material is arranged, and this lower part An upper mold to which a vacuum suction pipe having a porous filter made of a porous material having a porosity of 40% to 10% is connected to the mold in an airtight manner, and the inside of the cavity is interposed through the vacuum suction pipe. In this state, a negative pressure state is obtained, and in this state, the matrix resin contained in the matrix resin injecting machine is pressurized with pressurized air while the mesh hole ratio in the cavity from the resin injection port of the matrix resin is 1 to A matrix resin is pressed into and impregnated into a reinforcing fiber base material through a transmittance adjusting member made of 80% mesh material. At this time, the matrix resin is generated during a curing reaction. The by-products and low-viscosity resin consisting of molecular weight material was removed in order outside of the system while selected by the porous filter, then heating the reinforcing fiber base material impregnated with the matrix resin, the composite material by pressurizing A molding method of a composite material to be molded.   The method for molding a composite material according to claim 1, wherein the matrix resin is a thermosetting resin, and a viscous resin having a resin viscosity of 0.1 Pa.s to 1,000 Pa.s is used. The method for molding a composite material according to claim 1 or 2, wherein the transmittance adjusting member uses a mesh material made of glass cloth coated with polytetrafluoroethylene .   The method for forming a composite material according to claim 1, wherein the reinforcing fiber base material uses a carbon fiber cloth or a glass fiber cloth. A lower mold having a resin injection port of the matrix resin, the hermetically fitted to the lower mold, and a vacuum suction pipe with a porous filter made of a porous material porosity of 40% to 10% The upper mold is connected to the matrix resin injection port side in the cavity of the lower mold. A mold for molding a composite material provided with a transmittance adjusting member made of a mesh material having a mesh opening ratio of 1 to 80% . The mold for molding a composite material according to claim 5, wherein the transmittance adjusting member uses a mesh material made of glass cloth coated with polytetrafluoroethylene .

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