JPH042876A - Reinforcing carbon fiber mesh and preparation thereof - Google Patents

Abstract

PURPOSE:To provide the subject mesh having good adhesiveness to cement materials and capable of securing excellent workability by holding a carbon fiber bundle coated and impregnated with an epoxy resin containing SiO2 particles having a specific average particle size in a straight line state and simultaneously bonding only intersecting points of the fibers in the bundle to each other. CONSTITUTION:A carbon fiber bundle is coated and impregnated with an epoxy resin emulsion containing SiO2 particles comprising colloidal silica and having an average particle size of 1-100nm and wound on a lattice-like frame in one direction in parallel while being maintained in a straight line state. The frame is rotated at an angle of 90 degree and a carbon fiber bundle is also wound in the direction orthogonal to the first wound fiber bundle. The resultant body is heated and cured in such a state that the intersecting points of the fibers are brought into contact with each other to bond only the intersection portions to each other, thereby inexpensively providing the reinforcing carbon mesh having excellent adhesiveness to cement material cured products. The employment of the mesh as a reinforcing material improves the mechanical physical properties of a carbon fiber-inorganic plate in which the mesh is employed as a reinforcing material.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to carbon fiber mesh and carbon fiber mesh as reinforcement materials for hardened cement materials such as mortar and concrete, which are mainly used as building materials for roofs, floors, exterior walls, etc. The present invention relates to a method for manufacturing the same, and also to a carbon fiber reinforced inorganic plate using this carbon fiber mesh as a reinforcing material.

BACKGROUND OF THE INVENTION Due to its excellent mechanical properties such as specific strength, specific modulus of elasticity, etc. and chemical stability, carbon fiber has been recognized for its usefulness in a wide range of fields and has been used in large quantities. but,
Carbon fiber is rarely used alone, and is generally used as a reinforcing material for composite materials.

On the other hand, cementitious materials have a strong compressive strength when hardened.
Because it is inexpensive, it is a material that is used in large quantities mainly in the field of civil engineering and construction. However, due to its low tensile strength and brittleness, carbon fiber is often used together with various reinforcing materials.In recent years, carbon fiber has attracted attention as a reinforcing material. Carbon fiber reinforced cement (CFRC) reinforced with carbon fibers is known.

Carbon fiber reinforced cement (C: arbon fiber rein) is a composite of both carbon fiber and cement-based materials.
ForcedCement Composites,
CFRC (hereinafter referred to as CFRC) is characterized by its fiber's excellent mechanical and
Due to its chemical properties, it is expected to be a new high-grade construction material with properties such as strength, deformation, elasticity, and high durability that were not possible with conventional hardened cement materials, and in recent years it has been used for raised floors. -It is used as flooring material and curtain wall material.

By the way, it is generally said that interfacial strength is particularly important among the factors that determine the physical properties of composite materials. However, carbon fiber has chemical properties that cause it to have poor adhesion to cement-based materials. Therefore, the interfacial strength is weak, and the high strength and high modulus of carbon fiber cannot be fully demonstrated in the cured cement material.As a means to solve this problem, we blended epoxy resin emulsion and colloidal silica. A method of coating and impregnating carbon fiber bundles with resin has been reported (Japanese Patent Application Laid-Open No. 63-2038
Publication No. 78).

However, conventionally, when carbon fibers are used as carbon fiber bundles in a continuous fiber state, carbon m
#I After reinforcing the intersections of the bundles, the carbon fiber bundles are coated and impregnated with epoxy resin and cured to form a mesh, or carbon fiber bundles are impregnated with epoxy resin or polyester resin, and then crushed sand or the like is attached to the surface. The main method used is to make the surface uneven.

These are expected to be anchored by a mechanical anchor effect in order to supplement the interfacial strength between the carbon fiber and the hardened cement material. The fixation strength depends on the shear strength of the hardened cementitious material. However, since the intersection strength of the carbon fiber mesh processed in this way generally exceeds the shear strength of the hardened cementitious material within the mesh lattice, the hardened cementitious material is unlikely to undergo shear failure due to stress concentration at the anchorage. It has become.

Therefore, when using high-strength carbon fiber, CF
The strength development rate of carbon fibers in RC becomes low, and the high strength and high elasticity of carbon fibers result in no effect.

In addition, secondary processing of carbon fibers such as knitting the carbon fibers causes a significant increase in the cost of the carbon fiber no-sew product. Furthermore, knitting or twisting carbon fiber, which is a reinforcing material, in the tensile direction causes the fibers to curve, which lowers the apparent modulus of elasticity of the reinforcing material. It is not effective when using

Problems to be Solved by the Invention The present invention provides a carbon fiber mesh that is not expected to have only a mechanical anchor effect in order to increase the strength and rigidity of CFRC, and a method for producing it in a simple one step. By providing this, it is possible to improve the strength development rate of carbon fiber in CFRC, reduce the processing cost of carbon fiber mesh, and solve the above-mentioned problems such as shear failure of hardened cement material and high cost of carbon fiber mesh. This is what we are trying to solve.

In addition, by using carbon fiber mesh with controlled interfacial adhesive strength as a reinforcing material for cement-based material cured inorganic boards, we can create carbon fiber-reinforced inorganic boards that fully utilize the high strength and high elasticity properties of carbon fibers. It provides:

Means and action for solving the problem The reinforcing carbon fiber mesh of the present invention has an average particle size of 1 to 1
Carbon fiber bundles coated and impregnated with an epoxy resin containing SiO2 particles of 0.00 nm are made by bonding only the intersection points while maintaining a straight line, and intersecting each other at right angles.

Furthermore, the carbon fiber bundles are coated and impregnated with an epoxy resin containing SiO2 particles with an average particle size of 1 to 1100 nm, and the treated carbon fiber bundles are arranged in parallel in one direction while maintaining an orthogonal state, and the uncured A method for manufacturing reinforcing carbon fibers, characterized in that the reinforcing carbon fibers are overlapped in orthogonal directions and cured with the intersection portions in contact, and the reinforcing carbon fiber mesh is made of cement-based material hardened material as the main component. This is a high-performance carbon fiber-reinforced inorganic board characterized by containing carbon fiber in the inorganic board.

The carbon fiber mesh in the present invention has good adhesion between the epoxy resin containing ultrafine particles of Sin and the cement-based material cured carbon fiber, which coats the surface of the carbon fiber mesh. The interfacial strength between the cured bodies is improved.

Therefore, it is not necessary for the intersection points of the carbon fiber meshes to have sufficient intersection strength to expect a mechanical anchor effect, but it is sufficient to have sufficient intersection adhesive strength to ensure workability. This carbon fiber mesh can reinforce a hardened cementitious material inorganic board by orienting the carbon fiber bundles in the direction in which a tensile load is applied.

The process of manufacturing this carbon fiber mesh includes, for example, a process of coating and impregnating carbon fiber bundles using the prepreg method, winding them around a frame, arranging the carbon fiber bundles in parallel, and then rotating the frame by SO degrees. This process consists of a step of manufacturing a wound carbon fiber mesh by overlapping coated and impregnated carbon fiber bundles in a direction perpendicular to the carbon fiber bundles arranged in parallel.

By controlling the tension during winding, it is possible to control the intersection strength of the carbon fiber mesh. Another method is to coat and impregnate carbon fiber bundles using the prepreg method, and then apply S to carbon fiber bundles on protrusions arranged in two parallel rows.
This process consists of arranging the carbon fiber bundles parallel to each other in a flat shape, placing the two uncured carbon fiber bundles on top of each other at right angles, and curing them in this state.

When carbon fiber mesh is manufactured using such a simple method, processing costs can be reduced because the surface coating to improve interfacial strength and the intersection bonding treatment of the mesh can be performed using the same resin and in the same process. There will also be an economic effect. When using relatively expensive materials such as carbon fibers, it is also an important factor to reduce secondary processing costs to produce carbon fiber meshes.

The shape of the carbon fiber mesh of the present invention is such that the carbon fibers are substantially perpendicular to the X-axis direction and the y-axis direction, and the amount of carbon fibers is determined by the shape, physical properties, etc. of the hardened cement material to be reinforced. In addition, the cross-sectional shape of the carbon fiber bundles forming the carbon fiber mesh is preferably oval in order to increase the bonding area with the hardened cement material, but depending on the reinforcement position, large or rectangular ones may also be used. The cross-sectional shape is not particularly limited.

The 5in2 ultrafine particles used in the present invention are active colloidal silica, and have an average particle size in the range of 1 to 100 nm layers. When the average particle size is larger than 100 nm,
If the average particle size is smaller than lnm, it is difficult to blend with the epoxy resin due to the strong cohesive force, which is undesirable because the interfacial adhesion with the cured cement material decreases, and it aggregates and reacts in the epoxy resin. Sexuality will fall.

Analysis of SiO2 ultrafine particles in epoxy resin is carried out by Tran
smith Electron Microsco
This is possible using pe (T E M) and the like.

The epoxy resins used include bisphenol A type, bisphenol F type, bisphenol AD type, and novolac type, and they may also be modified with urethane, tar, phenol, xylene, coumarone, ketone, etc. How to use epoxy resins It is preferable to add various emulsifiers to form an O/W type emulsion.

As the curing agent, known curing agents such as amine type, polyaminoamide type, acid and acid anhydride type can be used. When curing the epoxy resin, various curing accelerators may be added. Further, when dispersing the SiO2 ultrafine particles, a small amount of a surfactant, a coupling agent, etc. may be added as necessary to improve dispersibility.

The carbon fibers used may be either PAN-based carbon fibers made from polyacrylonitrile (PAN) fibers or pitch-based carbon fibers made from coal, petroleum-based tar and pitch, and the surface of the carbon fibers is epoxy. X-ray photoelectron spectroscopy (X-RA7 pho
Surface analysis using toelectron 5pectroscopy revealed that the oxygen atom/carbon atomic ratio (0/C) was 0.
It is preferable to use an oxidation treatment of 0.07 or more. As the oxidation treatment method, known methods such as electrolytic oxidation method and plasma oxidation method can be used.

Sizing treatment may or may not be performed, but if sizing treatment is performed, it is preferable to use a sizing agent containing an epoxy group for the epoxy resin matrix.The carbon a fibers preferably have a continuous 41M shape. .

On the other hand, by using panels made mainly of mortar, concrete, etc., and carbon fiber mesh that has been treated as described above as a reinforcing material, compared to ordinary carbon fiber mesh,
It is possible to provide a high-strength, high-elastic carbon fiber-reinforced inorganic board that takes advantage of the strength characteristics of carbon fiber.

This carbon fiber-reinforced inorganic board has very good adhesion at the interface between the carbon fiber and the cured cement material, so it can be made into a carbon fiber mesh that is only fixed by the anchor effect by weaving or bonding the intersection points. Compared to this, the stress applied to the carbon fiber-reinforced inorganic board is transmitted to the carbon fibers slowly through the interface layer between the carbon fibers and the hardened cement material.

Therefore, the concentration of stress on the hardened cementitious material can be reduced, and the high strength and high elasticity of carbon fiber can be utilized in the hardened cementitious material, which improves the mechanical properties and reliability as a building material. improve.

Furthermore, the bonding process at the intersection points is different from the conventional method that only expected an anchor effect, and only needs to be strong enough to ensure workability. Therefore, carbon fiber mesh is easy to manufacture, reduces processing costs, and at the same time provides reinforcement. It is possible to easily change the amount and orientation of reinforcing carbon fibers depending on the strength and shape of the cured cement material.

Examples Example 1 PAN-based carbon fiber bundle (strength: 285 kg/am2.
Elastic modulus: 21.5t/mm2. Fineness: 0.88g
/m, density: 1.81g/c grave 3, 12,000
An O/W type epoxy resin emulsion (base ingredient: Epicor) 828 containing 10 wt% of SiO2 ultrafine particles (average particle size: 10 nm) was prepared using colloidal silica using a prepreg method using a filament (manufactured by Heitzl Gelafil, UK).
; manufactured by Yuka Shell).

After coating and impregnating, the carbon fiber bundle is held in a straight state and wound in parallel in one direction around a lattice-like frame. Next, the carbon fiber bundle is wound in an uncured state in a perpendicular direction in the same manner, and the intersection points are A carbon fiber mesh was prepared by curing the carbon fiber bundle wound at 80° C. with the carbon fibers attached thereto. This carbon fiber mesh was coated with mortar (W/C=0.42, S/C=0
．． 5. It was used as a reinforcing material for ordinary Portland cement and No. 8 crushed sand.

The shape of the carbon fiber reinforced inorganic board is 500 (horizontal) x 500
(Length) x 18 (Height) - Binding, carbon fiber mesh was covered with two layers and reinforced on the bottom surface. The volume percent (Vf) of carbon fibers in the carbon fiber-reinforced inorganic board was set to 1.82%.

After 4 weeks of underwater curing, a central loading test using 4-point support was carried out at a loading rate of 0.5 kg in increments, and the load applied to the inorganic board and the displacement immediately below the loading point were continuously measured. The loading part was 50 mm in diameter, and the support part was 30 x 30 mm.

The experimental results are shown in Table 1. Further, FIG. 1 shows a load-displacement curve. From the experimental results, the displacement directly below the loading point is 4
1, the maximum load was 1039.6 kgf, which indicates that it is a carbon fiber-reinforced SIa plate with excellent strength and rigidity.

Example 2 PAN-based carbon fiber bundles similar to those in Example 1 were prepared using colloidal silica using the prepreg method to form an O/W type epoxy resin emulsion (base resin) containing 10 wt% of SiO2 ultrafine particles (average particle size: 80n). : Epicoat 828 (manufactured by Yuka Shell) was coated and impregnated.

After coating and impregnating, the carbon fiber bundle is held in a straight state and wound in parallel in one direction on a lattice-like frame, and then carbon I11
．． A carbon fiber mesh was prepared by winding up the I1 bundle in an uncured state in the same manner in the orthogonal direction, and curing the wound carbon fiber bundle with the intersection portions attached at 80°C. This carbon fiber mesh was coated with mortar (W/C=0.42, S
/C=0.5, ordinary Portland cement, aggregate: No. 8 crushed sand).

The shape of the carbon fiber reinforced panel is 500 (horizontal) x 500 (
Length) The volume percent (Vf) of carbon fibers in the carbon fiber-reinforced inorganic board was set to 1.82%.

After 4 weeks of underwater curing, the load applied to the inorganic board and the displacement immediately below the loading point were continuously measured using central loading with 4-point support at a loading rate of 0.5 layers/win. The loading part was 50 mm in diameter and the support part was 30 x 30 mm. The experimental results are shown in Table 1. Further, FIG. 1 shows a load-displacement curve. From the experimental results, it was found that the displacement directly below the loading point was about 4 strands, and the maximum load was 958.4 kgf.

This shows that by changing the average particle size of the SiO2 ultrafine particles in colloidal silica, the strength of the carbon fiber reinforced inorganic plate can be changed and controlled.

Example 3 PAN-based carbon fiber bundles similar to those in Example 1 were prepared using colloidal silica using the prepreg method to form an O/W type epoxy resin emulsion (base resin) containing 10 wt% of SiO2 ultrafine particles (average particle size: 10 nm). : Epicoat 828 (manufactured by Yuka Shell Co., Ltd.) was coated and impregnated.

After coating and impregnating, the carbon fiber bundle is held in a straight state and wound in parallel in one direction around a lattice-like frame. Next, the carbon fiber bundle is wound in an uncured state in a perpendicular direction in the same manner, and the intersection points are A carbon fiber net was prepared by curing the carbon fiber bundle wound at 80° C. with the carbon fibers attached thereto. 1 mortar (W/C=0.42, S/C=0.
5. It was used as a reinforcing material for ordinary Portland cement and No. 8 crushed sand.

The shape of the carbon fiber reinforced inorganic board is 500 (horizontal) x 500
(Length) X1B (Height) ■, carbon fiber mesh was used as a cover and reinforced on the bottom surface. The volume percent (Vf) of carbon fibers in the carbon fiber-reinforced inorganic board was set to 0.73%.

After 4 weeks of underwater curing, the load applied to the inorganic plate and the displacement immediately below the loading point were continuously measured using central loading with 4-point support at a loading rate of 0.51 in/inch. The loading part was 50 mm in diameter, and the support part was 30 x 30 layers. The experimental results are shown in Table 1. Further, FIG. 1 shows a load-displacement curve.

The experimental results show that the maximum load is 512.8 kgf when the displacement directly below the loading point is about 15 layers. This shows that by changing the amount of reinforcing carbon fibers, both the strength and rigidity of the carbon fiber-reinforced inorganic board can be changed and controlled.

Comparative Example 1 PAN-based carbon fiber bundle (strength: 430 kg #++12
, elastic modulus: 23.5t/ls2. Fineness: 0.83g
/s+, density: 1.78g/c intestine 3.12,000
Filament: manufactured by Asahi Nippon Carbon Co., Ltd.), e for the warp,
Two ooo filaments are used to create a straight weft (12
, Goo filaments) were alternately sandwiched from above and below to create a mesh-like carbon fiber net with 12,000 filaments in both the warp and the weft, with the intersections constrained.

Epoxy resin made by diluting this carbon fiber mesh with acetone (base resin: Araldite GY-280; manufactured by Ciba Geigy; hardening agent: dicyandiamide; manufactured by Ciba Geigy)
Coated and impregnated. This carbon fiber mesh was cured at 140°C, and mortar (W/C=0.42, S/C=0
．． 5. It was used as a reinforcing material for ordinary Portland cement and No. 8 crushed sand.

The shape of the carbon fiber reinforced inorganic board is 500 (horizontal) x 500
(Length) x 18 (Height) ■, and reinforced the bottom surface by covering it with carbon fiber mesh and tightening it twice. The volume percent (Vf) of carbon fibers in the carbon fiber-reinforced inorganic board was set to 1.82%.

After curing in water for 4 weeks, the load applied to the inorganic board and the displacement at the loading point were continuously measured using central loading with 4-point support at a loading rate of 0.5 ■■/sin. The loading part was 50 mm in diameter, and the support part was 30 x 30 am.

The experimental results are shown in Table 1. Further, FIG. 1 shows a load-displacement curve. As a result, the mechanical properties of the carbon fiber-reinforced inorganic plate using carbon fiber mesh as a reinforcing material by the conventional method, considering only the mechanical fixation at the intersections of the carbon fiber meshes, were as follows: It can be seen that although the carbon fiber conical strength and the amount of reinforcing carbon fiber are higher than the inorganic board, both the strength and rigidity are at the same level.

Comparative Example 2 PAN-based carbon fiber bundle (strength: 430 kg/recommendation 2,
Elastic modulus: 23.5t/Peng II2, fineness: 0.83g
/Peng, density: 1.78g/c layer 3.12. Goo filament (manufactured by Asahi Nippon Carbon Co., Ltd.), e and oo filaments for the warp.
o Using two filaments, weft a straight weft (12,0
00 filaments) were alternately sandwiched from above and below to create a mesh-like mesh-like carbon fiber yarn with 12,000 filaments in both the warp and weft with restrained intersections. This carbon fiber mesh was diluted with acetone using epoxy resin (base resin: Araldai) G Y-280, manufactured by Ciba Geigy, curing agent:
Dicyandiamide (manufactured by Ciba Geigy) was coated and impregnated.

This carbon fiber mesh was cured at 140°C and used as a reinforcing material for mortar (W/C=0.42, S/C=0.5, ordinary Portland cement, No. 8 crushed sand).

The shape of the carbon fiber reinforced inorganic board is 500 (horizontal) x 500
(Longitudinal) The volume percent (Vf) of carbon fibers in the carbon fiber-reinforced inorganic board was set to 1.17%.

After 4 weeks of underwater curing, the load applied to the inorganic board and the displacement at the loading point were continuously measured using central loading with 4-point support at a loading rate of 0.5 mm/sin. The loading part had 50 layers φ, and the supporting part had 30×30 layers.

The experimental results are shown in Table 1. Further, FIG. 1 shows a load-displacement curve. As a result, the mechanical properties of the carbon fiber-reinforced inorganic board using carbon fiber mesh as a reinforcing material by the conventional method, considering only the mechanical fixation at the intersections of the carbon fiber meshes, were as follows: compared to,
It can be seen that although the carbon fiber strength and the amount of reinforcing carbon fiber are higher, both the strength and rigidity are at the same level.

(Left below) As shown in the examples above, the reinforcing carbon fiber mesh, in which the surface of the carbon fiber bundles is coated with an epoxy resin containing ultrafine SiO2 particles and the intersections of the carbon fiber bundles are bonded, is made of a cement-based material cured material. Because of its good adhesion with carbon fibers, it is suitable as a reinforcing material for hardened cementitious materials, and therefore high-performance carbon fiber-reinforced inorganic plates that take advantage of the strength characteristics of carbon fibers can be produced.

Effects of the Invention According to the present invention, it has become possible to obtain a reinforcing carbon fiber mesh that has good adhesion to the cured cement material and has ensured workability. Therefore, compared to the case of using conventional carbon fiber mesh that only takes mechanical fixation into consideration, it is possible to fully and easily utilize the characteristics of carbon fiber, and the mechanical properties of the carbon fiber reinforced inorganic board can be improved. Improved.

[Brief explanation of the drawing]

Figure 1 is a diagram showing the relationship between the load due to center loading of a carbon fiber reinforced inorganic plate and the displacement of the carbon fiber reinforced inorganic plate just below the loading point.
1 shows the results of Example 2, Curve 1 shows the results of Example 3, Curve 1 shows the results of Comparative Example 1, and Curve 2 shows the results of Comparative Example 2.

Claims (3)

[Claims] (1) A reinforcing carbon fiber mesh made by bonding only the intersections of carbon fiber bundles coated and impregnated with an epoxy resin containing SiO_2 particles with an average particle size of 1 to 100 nm while maintaining their linear state. (2) Cover and impregnate carbon fiber bundles with epoxy resin containing SiO_2 particles with an average particle size of 1 to 100 nm, and arrange the treated carbon fiber bundles in parallel in one direction while keeping them in a straight state. A method for manufacturing a reinforcing carbon fiber mesh, which is characterized by stacking the carbon fiber mesh in a hardened state in perpendicular directions and hardening the mesh with the intersection points in contact with each other. (3) A carbon fiber-reinforced inorganic board, characterized in that the reinforcing carbon fiber mesh according to claim 1 is contained in an inorganic board whose main component is a hardened cement material.