KR101388242B1 - Method for making hybrid fpr having carbon fiber and aramid fiber - Google Patents

Abstract

The present invention relates to a method for producing isotropic hybrid seismic reinforcing fiber reinforced plastic (FRP) for seismic reinforcement, and more specifically, it is possible to mix woven carbon fibers and woven aramid fibers as a building reinforcing material or to mix carbon fibers and aramid fibers. The present invention relates to a method for producing fiber reinforced plastic (FRP).
The method of manufacturing the isotropic hybrid seismic reinforcing fiber reinforced plastic (FRP) for seismic reinforcement according to the present invention comprises impregnating an aramid fiber woven fabric made of aramid fiber into an epoxy resin to prepare aramid fabric prepreg, and carbon fiber woven carbon fiber. Impregnating a woven fabric with an epoxy resin to prepare a carbon fiber fabric prepreg, or weaving a hybrid fabric using carbon fibers and aramid fibers to impregnate the epoxy resin to produce a carbon fiber-aramid fiber blend prepreg;
Performing mold release treatment on the mold surface, laminating the aramid fabric prepreg and the carbon fiber fabric prepreg in multiple layers on the upper and lower mold surfaces, or laminating a plurality of the carbon fiber-aramid fiber blend prepregs;
Closing the upper and lower molds, applying a vacuum to the mold, and then raising the temperature to 75 to 85 ° C. in the autoclave, and then primarily curing the mixture at 75 to 85 ° C. for 50 to 70 minutes;
After the first curing, the temperature is raised to 120 to 130 ° C., and then the second curing is performed by holding at 120 to 130 ° C. for 60 minutes to 120 minutes; And
After drying in a natural state, the step of deserting in a mold mold to complete the product; includes.

Description

METHODS FOR MAKING HYBRID FPR HAVING CARBON FIBER AND ARAMID FIBER}

The present invention relates to a method for producing isotropic hybrid seismic reinforcing fiber reinforced plastic (FRP) for seismic reinforcement, and more specifically, it is possible to mix woven carbon fibers and woven aramid fibers as a building reinforcing material or to mix carbon fibers and aramid fibers. The present invention relates to a method for producing fiber reinforced plastic (FRP).

Fiber Reinforced Plastics (FRP, Fiber Reinforced Plastics) is a generic name for resins with improved mechanical strength by incorporating a fiber base in a synthetic resin. It is used for a wide range of applications such as bathtubs, yachts, golf clubs, and industrial insulation materials, taking advantage of its long lifespan, light weight, strong strength, and anti-corruption. Chemically, it is divided into G-FRP which mixes glass fiber and C-FRP which mixes carbon fiber, and it is divided into silicone type, phenol type, etc. according to the resin which becomes a base.

Currently, FRP for building reinforcement is made of glass fiber (G-FRP), carbon fiber (C-FRP), aramid fiber (A-FRP), and carbon fiber composite material in the form of reinforcement plate (FLAT BAR) or rod (ROD). It is sold. Building reinforcement plate made of carbon fiber has high tensile strength and tensile elasticity. Aramid is less tensile strength and elasticity than carbon fiber. Aramid fibers are inferior in tensile strength and tensile elasticity compared to carbon fibers, but have high impact strength, high abrasion resistance, high resistance to breaking and vibration damping effect compared to carbon fibers.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a table and graph comparing vibration damping with TECHNORA (aramid brand name of TEIJIN), KEVLAR (Aramid brand name of DEPONT), and carbon fiber, which are aramid products. As can be seen in Figure 1, the aramid fibers can be seen that the vibration damping effect is higher than the carbon fibers. As the earthquake occurs, the building continues to crack due to vibration, and if the seismic reinforcement FRP is manufactured using aramid fibers having a vibration damping effect, it is expected to minimize the collapse of the building due to aftershocks.

On the other hand, existing products are molded by using one-way prepreg, or manufactured by drawing molding using carbon filament. When manufactured by conventional one-way prepreg or drawing molding (ex. String), it has strong force in the fiber length direction but very weak force because it is bonded only by resin bonding in the right direction. Therefore, the development of the hybrid seismic reinforcement FRP which has isotropy as a building material for seismic reinforcement is calculated | required.

The present invention is to solve the above problems, the present invention combines the advantages of carbon fiber and the advantage of aramid fiber tensile strength, tensile elasticity, vibration damping, isotropic seismic reinforcement method of manufacturing FRP, that is, An object of the present invention is to build an FRP for building reinforcement with high impact resistance and abrasion resistance of the aramid fibers while maintaining the tensile strength and tensile elasticity of the carbon fiber, the vibration damping effect in the event of an earthquake, which can effectively protect the building during an earthquake. It is to provide a method for producing FRP.

The objects of the present invention are not limited to the above-mentioned objects, and other objects not mentioned can be clearly understood from the following description.

In order to achieve the above object, the method of manufacturing the seismic reinforcing FRP of the present invention is a manufacturing method of an isotropic hybrid seismic reinforcing fiber reinforced plastic for seismic reinforcement,

Aramid fiber woven fabric made of aramid fibers is impregnated with epoxy resin to prepare aramid fabric prepreg, and carbon fiber woven fabric made of carbon fiber is impregnated with epoxy resin to prepare carbon fiber fabric prepreg, or carbon fiber and aramid fiber Weaving a hybrid fabric using the step of impregnating the epoxy resin to prepare a carbon fiber-aramid fiber blend prepreg;

Performing mold release treatment on the mold surface, laminating the aramid fabric prepreg and the carbon fiber fabric prepreg in multiple layers on the upper and lower mold surfaces, or laminating a plurality of the carbon fiber-aramid fiber blend prepregs;

 Closing the upper and lower molds, applying a vacuum to the mold, and then raising the temperature to 75 to 85 ° C. in the autoclave, and then primarily curing the mixture at 75 to 85 ° C. for 50 to 70 minutes;

After the first curing, the temperature is raised to 120 to 130 ° C., and then the second curing is performed by holding at 120 to 130 ° C. for 60 minutes to 120 minutes;

After drying in a natural state, the step of deserting in a mold mold to complete the product; includes.

According to a preferred embodiment, in the step of stacking the prepreg, the stacking method of the prepreg is laminated so that the length direction of the woven fibers in the prepreg to be laminated with respect to the mold surface is different for each layer.

According to a preferred embodiment, in the process of laminating the aramid fabric prepreg and the carbon fiber fabric prepreg, the prepregs are laminated so as to be symmetrical with respect to the center plane when the upper and lower mold dies are combined.

As described above, when manufacturing the seismic reinforcement FRP products according to the present invention, it is possible to produce an isotropic seismic reinforcement FRP having a vibration damping effect while having a higher strength and tensile strength than conventional products. In addition, by adjusting the ratio of carbon fiber and aramid fiber according to the seismic reinforcement design, it is possible to produce a seismic reinforcement FRP optimized for buildings.

In addition, the existing carbon fiber reinforcement plate or rod was manufactured by relying on the total amount of imports, but by applying low-priced aramid fiber that can be produced domestically compared to carbon fiber, it is possible to use not only existing high-end building structures but also ships, Applying to various fields such as industrial structures, civil structures, etc., there is an advantage that ultimately protects buildings and lives.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a table and graph comparing vibration damping with TECHNORA (aramid brand name of TEIJIN company), KEVLAR (aramid brand name of DEPONT company) and carbon fiber, which are aramid products.
Figure 2 is a flow chart for explaining the process of manufacturing a seismic reinforcement isotropic hybrid seismic reinforcing fiber reinforced plastics of the present invention.
3 and 4 is a test report for the specimen produced according to the embodiment of the present invention.

The present invention uses a combination of carbon fibers and aramid fibers in the manufacture of a plate or rod for seismic reinforcing reinforcement, excellent strength, elastic modulus, chemical resistance of the advantages of carbon fibers, seismic effects of the advantages of aramid, It is an isotropic hybrid seismic reinforcing fiber reinforced plastic product for seismic reinforcement utilizing impact resistance and abrasion resistance.

Conventional building FRP products are manufactured using one type of fiber, but in the present invention, by using the advantages of each fiber to produce a hybrid type of building reinforcement FRP to compensate for the disadvantages of each fiber, building structures susceptible to earthquakes It is a plate or rod product for reinforcing composite structure that can improve seismic performance.

The FRP product according to the manufacturing method of the present invention is manufactured using carbon fiber fabric, aramid fabric or prepreg in the form of a mixture of carbon fiber and aramid to give isotropy, thereby reinforcing isotropic building having strength in various directions. It is a FRP product. In addition, it is possible to express aesthetics beautiful to the building by the fabric pattern unique to carbon fiber.

Hereinafter, with reference to the accompanying drawings, it will be described in more detail with respect to the manufacturing method of the seismic reinforcement isotropic hybrid seismic reinforcing fiber reinforced plastic of the present invention.

Figure 2 is a flow chart for explaining the process of manufacturing the seismic reinforcement isotropic hybrid seismic reinforcing fiber reinforced plastics of the present invention.

Fiber-reinforced plastic of the present invention is a fiber-reinforced plastic mixed with aramid fiber and carbon fiber, while maintaining the high vibration damping effect while maintaining the impact resistance and wear resistance of the aramid fiber while maintaining the tensile strength and tensile elasticity of the carbon fiber By producing a building reinforcement FRP, when using the fiber-reinforced plastic of the present invention as a building material is a seismic reinforcement FRP product that can effectively protect the building in the event of an earthquake in the building.

Referring to FIG. 2, first, prepreg is prepared by impregnating fibers in an epoxy resin. There are two ways to make prepregs. One method is to produce aramid fabric prepreg and carbon fiber fabric prepreg separately, and the other is to separate carbon fiber and aramid fiber into warp and weft yarn, and hybrid carbon fiber-aramid fiber blend fabric to epoxy resin Impregnation is a method of producing a carbon fiber-aramid fiber blend prepreg.

 The aramid fabric prepreg and the carbon fiber fabric prepreg are manufactured separately by impregnating aramid fiber woven fabrics each individually woven with aramid fiber into an epoxy resin to prepare aramid fabric prepreg and weaving with carbon fiber in the same manner. The carbon fiber woven fabric is impregnated with an epoxy resin to prepare a carbon fiber fabric prepreg. Prepreg is produced in the form of a roll, which is impregnated with an epoxy resin so that it does not fall off when wound on a roll, and a release film and a release paper are attached to both sides. When prepreg is laminated, the release paper is removed and laminated (laminated). Each separately produced aramid fabric prepreg and carbon fiber fabric prepreg are laminated at a predetermined ratio. By a predetermined ratio is meant the number of laminated aramid fabric prepregs and carbon fiber fabric pregs, which will be freely chosen by one of ordinary skill in the art according to the properties and properties required in the finished product. At the time of laminating, it is preferably laminated in the upper and lower mold dies symmetrically with each other. If two aramid fabric prepregs and six carbon fiber fabric prepregs are laminated in a total of 8 sheets, if the bottom mold mold is laminated with carbon + aramid + carbon + carbon, the upper mold mold is stacked in the same manner. When the molds are combined, they are stacked to be symmetrical with respect to the center plane. That is, the stacked prepregs have a structure in which the top and bottom are symmetrical with respect to the center plane. As such, the reason for laminating the symmetry with respect to the center plane is to prevent warpage from occurring in a specific direction. If the symmetry is not symmetric with respect to the center plane, the vibration damping effect of the aramid fibers and the carbon fibers is different, which is because warping occurs in a specific direction.

On the other hand, the stacking method of the prepreg is preferably laminated so that the lengthwise direction of the woven fiber in the prepreg laminated to the mold surface is different for each layer. That is, the prepregs are stacked at a predetermined angle for each layer. This lamination method is for the fiber-reinforced plastic of the present invention to have isotropy. When prepreg is manufactured by weaving fibers into plain or twill weave, it is true that the prepreg is formed by using a unidirectional prepreg in one direction or a method of forming by drawing. By laminating slightly differently, the isotropy can be further improved.

As described above, the aramid fabric prepreg and the carbon fiber fabric prepreg may be separately manufactured and laminated at a predetermined ratio, but the carbon fiber and the aramid fiber blend are mixed by dividing the carbon fiber and the aramid fiber into warp and weft yarns. The fabric may be impregnated with an epoxy resin to produce a carbon fiber-amide fiber blend prepreg, which may be laminated symmetrically on the upper and lower portions of the mold surface. Although this method is more difficult to manufacture, it is more preferable in that it has uniform bending property and uniform physical properties.

Before laminating | stacking a prepreg to a vertical mold die, of course, a mold release process is performed with respect to a vertical mold surface. This is to make it easy to be deserted at the time of filming the product after the molding of the product will be referred to as a conventional general technique.

After prepreg is laminated on the upper and lower mold surfaces, the upper and lower molds are closed and a vacuum is applied to the mold, and then the temperature is raised to 75 to 85 ° C. in an autoclave, and then maintained at 75 to 85 ° C. for 50 to 70 minutes to cure the first. Go through the steps. Although the primary molding conditions have a curing time of 50 to 70 minutes at a temperature of 75 to 85 ℃, more preferably it is cured by holding at about 60 minutes at a temperature of 80 ℃. The reason for the first curing at about 80 ℃ lower than the secondary curing temperature is to increase the completeness of the product by expanding the epoxy resin to partially expand to fill the empty space and not to form bubbles or space in the epoxy resin.

Next, after the first curing, the temperature is raised to 120 to 130 ° C., and then the second curing is performed by maintaining at 120 to 130 ° C. for 60 minutes to 120 minutes. Secondary molding conditions are carried out for a longer time at 120 ~ 130 ℃, a temperature higher than the first molding conditions, more preferably, the second curing is carried out by holding at 125 ℃ for 70 minutes.

Next, after the mold mold is naturally cooled, the product is deserted from the mold mold to complete the product.

Thus, the product produced by the above manufacturing method corresponds to an isotropic hybrid seismic reinforced fiber reinforced plastic (FRP) product that can be used for seismic reinforcement.

[Example]

Example 1

Aramid fabric prepreg impregnated with aramid fiber woven fabric (plain weave) in epoxy resin and carbon fiber fabric prepreg impregnated with carbon fiber woven (plain weave) carbon fiber woven fabric in epoxy resin The upper and lower surfaces of the plate mold mold were laminated. That is, one aramid fabric (plain weave) prepreg and three carbon fiber fabric prepregs are laminated on the upper and lower mold surfaces, respectively, and two aramid fabric (plain weave) prepregs and six carbon fiber fabric prepregs are used. Lamination was carried out using flags. That is, the carbon fiber fabric prepreg and the aramid fabric prepreg were laminated at 75:25 (ie, 3: 1). At this time, the prepregs stacked on the upper and lower surfaces of the mold were laminated so as to be slightly different in direction, and the prepregs of the upper and lower molds were stacked to be symmetrical with each other. After laminating all the prepregs on the upper and lower mold surfaces, the upper and lower molds were closed, and the mold was put in a vacuum state, the temperature was raised to 80 ° C. in the autoclave, and then maintained at 80 ° C. for 60 minutes to cure first. Then, after raising the temperature to 125 degreeC, it maintained at 125 degreeC for 70 minutes. After the molding was finished, the mold mold was naturally cooled and then deserted in the mold. As a result, a hybrid seismic reinforcement FRP having a carbon fiber and aramid mixed at 75:25 (ie, 3: 1) was prepared.

Example 2

Hybrid seismic reinforcement FRP was prepared in the same manner as in Example 1, but four aramid fabric (plain weave) prepregs and four carbon fiber fabric prepregs were laminated to produce seismic reinforcement FPR. In other words, a hybrid seismic reinforcing FRP having a 50:50 carbon fiber and aramid was prepared.

Example 3

Hybrid seismic reinforcement FRP was prepared in the same manner as in Example 1, but six aramid fabric (plain weave) prepregs and two carbon fiber fabric prepregs were laminated to produce seismic reinforcement FPR. That is, a hybrid seismic reinforcing FRP having a mixture of carbon fibers and aramids of 25: 75 (ie, 1: 3) was prepared.

Example 4

Four carbon fiber-aramid fiber blend prepregs prepared by impregnating an epoxy resin with a carbon fiber-aramid fiber blend fabric, which is a hybrid fabric woven with aramid with a weft of carbon fiber, were laminated on top and bottom molds, respectively.

Comparative Example 1

Using only carbon fiber fabric prepreg, four sheets were stacked in the upper and lower molds, respectively, to prepare FRP in the same manner as in Example 1.

Comparative Example 2

Using only aramid fiber fabric prepreg, four sheets were stacked in the upper and lower molds, respectively, to prepare FRP in the same manner as in Example 1.

Tensile strength and tensile elasticity of the specimens of the examples and comparative examples were measured. In the case of carbon fiber reinforced FRP (C-FRP) using only carbon fiber fabric prepreg in Comparative Example 1, the tensile strength was 802 MPa, tensile elasticity: 90 GPa, aramid fiber using only aramid fiber fabric prepreg In the case of reinforced FRP (A-FRP), the tensile strength was 473 MPa and the tensile elasticity was 15 GPa.

The specimens prepared in Examples 1 to 4 were requested by the Korea Apparel Testing and Research Institute, and the tensile strength and tensile elasticity were measured.

3 and 4 is a test report for the specimen produced according to the embodiment of the present invention. In FIG. 3, Sample 1 represents the specimen of Example 1, Sample 2 represents the specimen of Example 2, Sample 3 represents the specimen of Example 3, and Sample 4 of FIG. 4 represents the specimen of Example 4.

Tensile strength for the specimen was in accordance with ASTM 3039.

As a result of measuring the specimen of Example 1 (ASTM 3039), the tensile strength was 663 MPa and the tensile elasticity was 44 GPa. The specimen measurement result of Example 2 was the tensile strength of 636 MPa and the tensile elasticity of 61 GPa. The measured result was tensile strength 458 MPa and tensile elasticity 38 GPa. In addition, the measured value of the specimen of Example 4 using the carbon fiber-aramid fiber blend prepreg has a lower tensile strength of 430 MPa than the products of Examples 1 to 3 produced by mixing carbon fiber and aramid fiber, Tensile modulus has a high value of 66 GPa.

As described above, the specimens of Examples 1 to 4 had excellent physical properties compared to FRP (Comparative Example 2: Tensile strength 473 MPa, tensile elasticity 15 GPa) made of only aramid fabric prepreg, especially the content ratio of carbon fiber In these high Examples 1 and 2, they have excellent physical property values. It can be seen that in the case of Example 4 using a carbon fiber-aramid fiber blend prepreg, it is possible to produce a good tensile elasticity FRP. In the case of Example 4 (in the case of using a mixed prepreg), the production efficiency can be increased by unifying the materials.

As can be seen from the above experiment, the seismic reinforcing FRP products produced by mixing carbon fiber and aramid fiber or mixing carbon fiber and aramid fiber have lower tensile strength and tensile elasticity than carbon fiber alone, but aramid fiber It is possible to manufacture products with wear resistance, impact resistance and vibration damping effect.

In addition, when fabricating the seismic reinforced FRP products using aramid fibers has a low tensile elasticity and tensile strength. In addition, if used in a hybrid form, it is expected that seismic reinforced FRP products with higher tensile strength and tensile elasticity can be developed.

The property requirements of FRP for building reinforcement are 600MPa in tensile strength and 40GPa in tensile elasticity. If a building reinforcement FRP product is manufactured using mixed or mixed prepregs, it is possible to produce products with a tensile strength of 600 MPa and a tensile elasticity of 40 GPa or more.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention may be embodied otherwise without departing from the spirit and scope of the invention. Therefore, the embodiments disclosed in the present invention are not intended to limit the scope of the present invention, but are intended to be illustrative, and the scope of the present invention is not limited by these embodiments. The scope of protection of the present invention should be construed according to the following claims, and all technical ideas within the scope of the claims should be construed as being included in the scope of the present invention.

Claims (3)

In the manufacturing method of isotropic hybrid seismic reinforced fiber reinforced plastic for seismic reinforcement,
Aramid fiber woven fabric made of aramid fibers is impregnated with epoxy resin to prepare aramid fabric prepreg, carbon fiber woven fabric made of carbon fiber is impregnated with epoxy resin to prepare carbon fiber fabric prepreg, or
Weaving a hybrid fabric using carbon fibers and aramid fibers and impregnating them in an epoxy resin to prepare a carbon fiber-aramid fiber blend prepreg;
The mold surface is subjected to release treatment, and the upper and lower mold surfaces are laminated in multiple layers using the aramid fabric prepreg and the carbon fiber fabric prepreg, or the carbon fiber-aramid fiber blended prepreg is laminated in multiple layers. step;
Closing the upper and lower molds, applying a vacuum to the mold, and then raising the temperature to 75 to 85 ° C. in the autoclave, and then primarily curing the mixture at 75 to 85 ° C. for 50 to 70 minutes;
After the first curing, the temperature is raised to 120 to 130 ° C., and then the second curing is performed by holding at 120 to 130 ° C. for 60 minutes to 120 minutes;
After drying in a natural state, the step of deserting in a mold mold to complete the product; a method of manufacturing an isotropic hybrid seismic reinforcing fiber reinforced plastic for seismic reinforcement comprising a. The method of claim 1,
In the step of stacking the prepreg,
The prepreg lamination method is a method of manufacturing an isotropic hybrid seismic reinforced fiber reinforced plastics for seismic reinforcement, characterized in that the longitudinal direction of the woven fibers in the prepreg laminated to the mold surface is laminated so as to be different from each other. The method of claim 1,
In the laminating step of the aramid fabric prepreg and the carbon fiber fabric prepreg,
The prepreg is a method of manufacturing an isotropic hybrid seismic reinforcing fiber-reinforced plastic for seismic reinforcement, characterized in that the upper and lower molds are laminated so as to be symmetrical with respect to the center plane.

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