JP2002326285A - Continuous fiber reinforced plastic rod material excellent in heat resistance - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a non-conductive and non-magnetic continuous fiber reinforced plastic rod material excellent in heat resistance used as a reinforcing rod or a steel substitute material adapted to a concrete reinforcing material or a tensioning material. SOLUTION: The continuous fiber reinforced plastic rod material is constituted by coating the surface of fiber reinforced plastic due to continuous fibers, for example, aramide fibers, carbon fibers or the like with a heat-resistant resin having a glass transition point higher than that of the matrix resin of the heat-resistant resin by 20 deg.C or higher. At the heat-resistant resin, for example, there are an aromatic amino-epoxy resin derived from tetraglycidylaminodiphenylmethane or the like, polyether sulfone, a crosslinked polyaminoamide resin comprising phenylene bis-1,3-oxazole and an aromatic diamine or the like.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fiber reinforced plastic (hereinafter abbreviated as "FRP") having continuous fibers (long fibers) having a high tensile strength and a high elastic modulus as a reinforcing material. The present invention relates to an FRP bar suitable for architectural applications requiring fire prevention and fire resistance, that is, a bar as a concrete reinforcing material or a prestressed concrete tendon. As used throughout this specification, the term "bar" includes round, rectangular, irregular (rib, indented surface) rods, braided rods, stranded strands,
2 from a generally linear shape or its shape units, such as a grid
It shall mean a three-dimensional or three-dimensional assembled shape.

[0002]

2. Description of the Related Art Reinforcing materials for concrete structures for construction, such as reinforcing bars and tendons, are required to have mechanical properties such as high strength, high elasticity and high toughness, water resistance, alkali resistance, and the like.
It has salt water resistance, weather resistance, fire resistance and heat resistance. FRP composites made of high-strength continuous fibers such as aramid fibers, polyacrylonitrile-based carbon fibers, and glass fibers have been used in various industrial fields as advanced composite materials. Architecture,
Even in the field of civil engineering, composite materials made of high-strength fibers are superior in physical properties (tensile strength, elastic modulus) and superior to rebar, such as light weight, high strength, high elasticity, corrosion resistance, non-conductivity, and non-magnetism. In addition, in recent years, various problems such as deterioration of concrete structures, danger due to collapse, and the like, as a material that can replace reinforcing steel, It has been used as a substitute for PC (prestressed concrete) steel bars. In particular, aramid fiber reinforcement is noted for being superior in tensile strength, impact resistance, fracture toughness, vibration damping characteristics and non-conducting and non-magnetic compared to other fiber reinforcements. It has been used as a material to replace reinforcing bars in giant scientific research facilities such as nuclear magnetic resonance equipment and particle accelerators that require a strong electric field, and special buildings such as computer centers that dislike the induced current due to lightning. Contributing to pioneering.

[0003] As long as it is applied to architectural uses, such as a reinforcing material for reinforcing steel in place of a reinforced concrete member or a tendon material in place of a PC steel bar, fire prevention and fire resistance performance assuming a fire is required. It can be said that the above-mentioned composite material reinforced by continuous fiber has few problems in that it has poor heat resistance as compared with a reinforcing bar or the like. Originally, the above-mentioned fibers have high heat resistance. However, epoxy resins, unsaturated polyester resins, vinyl ester resins, and the like, which are frequently used as matrix resins, are weak to heat, so that the upper limit temperature for use is as low as 150 to 200 ° C.
In addition, a recently developed epoxy resin of a heat-resistant type generally has a high viscosity, so that its productivity is low, so that there is a problem that a necessary amount for producing a continuous fiber reinforced composite material cannot be secured. Nevertheless, attempts to increase the heat resistance of conventional matrix resins by some chemical means have not been easily successful.

[0004]

Therefore, in order to enhance the heat resistance and fire resistance of the continuous fiber reinforced composite material, extensive research has been carried out from all angles. Focusing on the fact that thermal degradation hardly occurs even if the temperature is slightly increased, by coating the composite material with a heat resistant resin, a continuous fiber reinforced composite material having excellent heat resistance and fire resistance can be obtained, As a result, it reached the possibility of conformity to the fire prevention and fire resistance requirements required by the Building Standards Law, and completed the present invention.

In the present invention, as a guide for evaluating heat resistance, parameters such as loss on heating of resin, tensile strength, elastic modulus, adhesive strength (adhesive strength), etc. are selected on the assumption of fire.
Their temperature dependence was studied. What is the effect of heat and temperature on tensile strength, modulus of elasticity, bond strength with concrete, and resin loss of composite material when continuous fiber-containing composite reinforcing bars in concrete members are exposed to heat (temperature change) What is the temperature of the reinforcement at the position inside the concrete member during a fire, what is the permissible temperature as a result, and what is the thickness of the refractory coating below the permissible temperature Various studies were carried out to determine whether or not it is good, mainly using carbon fibers and aramid fibers as the reinforcing material, and using conventional epoxy resins, polyester resins, vinyl ester resins and the like as the matrix resin. As a result, the following new findings were obtained.

[0006]

[Table 1]

[0007] Based on these results, it was determined that it could be concluded that the allowable temperature at the time of fire of the reinforcing bars was 250-300 ° C and the allowable temperature of the coating material itself was at least 200 ° C or more. It is believed that the cold tensile strength of the continuous fiber reinforcement is determined by the heat loss characteristics of the matrix resin. It is considered that the hot tensile strength of the continuous fiber reinforcement and the adhesion to concrete are determined by the glass transition temperature of the matrix resin. As described above, raising the Tg of the matrix resin and the temperature at which heating loss starts is
Although it is difficult to produce a continuous fiber reinforcement efficiently, if the surface of the continuous fiber reinforcement can be coated with a resin having a high Tg, this portion can exhibit a heat insulating layer and an effect of preventing deformation, and can be used as a hot tensile strength or an adhesive strength. We thought that we could improve. The present invention is based on the above research results and considerations.

[0008]

That is, the present invention provides (1) a rod formed from a fiber-reinforced plastic composite material comprising continuous fibers, and a glass of a matrix resin constituting the composite material on the entire surface thereof. A fiber-reinforced plastic rod excellent in heat resistance, which is coated with a heat-resistant resin layer having a glass transition point higher than the transition point by 20 ° C. or more. (2) Aramid fiber, acrylonitrile-based continuous fiber Carbon fiber, glass fiber, poly-
The fiber-reinforced plastic rod according to (1), wherein the fiber is a fiber selected from p-phenylene benzobisoxazole fibers, and the matrix resin is a resin selected from a phenolic epoxy resin, a vinyl ester resin, and an unsaturated polyester resin. (3) the heat-resistant resin layer is made of a resin selected from an aromatic amino epoxy resin, polyether sulfone, and a crosslinked polyaminoamide resin of phenylene bis-1,3-oxazole and aromatic diamine;
(1) The fiber-reinforced plastic rod according to (1) or (2), (4) the glass transition temperature of the matrix resin is 180.
° C or lower, and the glass transition point of the heat-resistant resin is 200 ° C or higher, the fiber-reinforced plastic rod according to any one of the above (1) to (3), (5) as a concrete reinforcing material or a prestressed concrete tendon The bar according to any one of (1) to (4), wherein the bar is used (6).
The present invention relates to the fiber-reinforced plastic rod according to the above (5) as a concrete reinforcing material or a prestressed tendon for a building for equipment requiring a strong magnetic field, a strong electric field, and non-conductivity.

Accordingly, the present invention relates to a rod formed from a fiber-reinforced plastic composite composed of continuous fibers, wherein the entire surface of the rod is 20 ° C. or more higher than the glass transition point of the matrix resin constituting the composite. A fiber-reinforced plastic bar excellent in heat resistance, characterized by being coated with a heat-resistant resin layer having a high glass transition point.

In the present invention, the "glass transition point" means the temperature at the point where the elastic modulus sharply drops, which is derived from the relationship curve between the dynamic viscoelasticity of resin and temperature by the non-resonant forced vibration method. . In this case, the measurement device used was Ryovibron (RHEOVIBRON DDV-II-EA) manufactured by Orientec Co., Ltd., and the measurement conditions were a frequency of 11 Hz and a temperature range of 24-200.
° C and the temperature rising rate is 2 ° C / min. The glass transition point is based on the value obtained from the peak temperature of the main dispersion (E "). The heat resistance of the reinforcing bar is about 250 to 300 ° C. based on the relationship between the resin heating loss, tensile strength, adhesion strength and temperature. Has an allowable temperature of

In the fiber-reinforced plastic rod according to the first aspect, the present invention is further characterized by the following points. Continuous fiber (long fiber) is aramid fiber, especially para-aramid fiber,
Fiber selected from carbon fiber (polyacrylonitrile), glass fiber, polyparaphenylene benzobisoxazole fiber and polyvinyl alcohol fiber, and matrix resin selected from phenolic epoxy resin, vinyl ester resin and unsaturated polyester resin Resin. The heat-resistant resin layer is made of a resin selected from an aromatic amino epoxy resin, polyether sulfone, and a crosslinked polyaminoamide obtained from phenylene bis-1,3-oxazole and an aromatic diamine. The glass transition point of the matrix resin is 180 ° C. or lower, and the glass transition point of the heat-resistant resin is 200 ° C. or higher. Fiber reinforced plastic bar used as concrete reinforcement or prestressed concrete tendon. Fiber-reinforced plastic bars as concrete reinforcement or prestressed concrete tendons for equipment buildings requiring strong magnetic fields, strong electric fields, and non-conductivity.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION First, a composite material of a core constituting a rod of the present invention will be described. Continuous fibers as reinforcing materials are aramid fibers, particularly para-aramid fibers (for example, Kevlar 29, 49, 149, etc.), Carbon fiber, especially polyacrylonitrile-based carbon fiber, glass fiber, especially zirconia-containing alkali-resistant glass (AR glass), glass fiber such as A glass, S glass, polyvinyl alcohol fiber (formalin condensate of PVA; vinylon), polyparaphenylene It can be selected from benzobisoxazole fibers (Zylon) and the like. However, aramid fiber, carbon fiber, glass fiber, and the like are selected if the physical properties, cost, and the like are comprehensively determined.

As the matrix resin, a conventionally known resin having a glass transition point of 180 ° C. or lower, for example, an epoxy resin (glass transition point of 100 to 170 ° C.), a vinyl ester resin (glass transition point of 150 ° C.), an unsaturated polyester resin (Glass transition point 150 ° C.). Examples of the epoxy resin include bisphenol A type, bisphenol F type, and phenol novolak type epoxy resins each containing a glycidyl ether group; glycidyl ester type epoxy resins (eg, epoxy resin from diglycidyl phthalate) and the like. Can be The vinyl ester resin is obtained by reacting an epoxy resin with an unsaturated dibasic acid such as acrylic acid or methacrylic acid, and is also called an epoxy acrylate resin. For example, bisphenol type, novolak type, urethane group-containing type (urethane acrylate) And vinyl isocyanurate. Examples of the unsaturated polyester resin include orthophthalic acid (ortho), heat-resistant isophthalic acid (iso), terephthalic acid (tere), bisphenol (bis), and neopentyl glycol.

The resin and the continuous fiber reinforced material are formed by various molding methods depending on the shape of the target rod material, for example, a rod is formed by a drawing method (a continuous fiber is impregnated with a resin, and is shaped by a heating mold. After curing, draw out).
Alternatively, another method for producing a round or rectangular rod is a method in which continuous fibers are aligned in one direction and solidified with a resin. The braided rod is manufactured by braiding a continuous fiber yarn into a braid and impregnating and curing with a resin, which is suitable for producing a tendon for prestressed concrete. The stranded wire rod is manufactured by impregnating a continuous fiber yarn twisted into a stranded wire shape with a thermosetting resin, molding and curing. The grid-like rod is formed by integrally molding a continuous fiber with a grid while impregnating the continuous fiber with a resin.

The continuous fiber reinforced plastic composite material thus obtained is further coated with a heat-resistant resin having a glass transition point higher than the glass transition point of the resin by 20 ° C. or more over the entire surface. Such resins and their glass transition points include aromatic aminoepoxy resins such as resins from tetraglycidylaminodiphenylmethane (230 ° C.), resins from diglycidylamino and aromatic substituted glycidylphenol (260 ° C.). ;
Polyether sulfone (225 ° C) (shown in the following chemical formula 1),
Ether sulfone resins such as polyaryl ether sulfone (285 ° C.) (shown in the following chemical formula 2); crosslinked polyamino obtained from 1,3-phenylenebisoxazole (shown in the following chemical formula 3) and an aromatic diamine such as diaminodiphenylmethane There are amides (250 ° C.), cross-linked polyester amide resins obtained from 1,3-phenylenebisoxazole and various carboxylic acids (aliphatic dicarboxylic acid + terephthalic acid, aliphatic dicarboxylic acid + p-oxybenzoic acid + salicylic acid). Further, imide resins such as polyetherimide (217 ° C.) and polyamide imide (280 to 290 ° C.) can also be used. In the present invention, the glass transition point is measured by a TG-40M type device manufactured by Shimadzu Corporation.

[0016]

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[0017]

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[0018]

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The coating thickness of the heat-resistant resin varies depending on the diameter of the rod (usually 3 to 10 mm in the case of a rod, 5 to 40 mm in the case of a stranded wire), but is preferably in the range of 0.1 to 2 mm. Below the lower limit, the heat-resistant effect is not exhibited, and above the upper limit, there is little meaning. The composite material is impregnated with a heat-resistant resin by dipping or coating or coated by injection molding of the heat-resistant resin to obtain the heat-resistant bar material intended for the present invention.

In order to enhance the adhesion (adhesion) to concrete or the like, the bar may be provided with surface irregularities, for example, in the shape of a chest wall in the longitudinal direction, unevenness or ribs, or solidified with sand. Depending on the purpose, the shape of the bar may be round or rectangular in cross section, or it may be assembled from a linear bar into a two-dimensional lattice, or assembled into a three-dimensional lattice for columns and corners.

Although the bar of the present invention can be used as a reinforcing member or a tendon for a concrete member, a concrete member containing such a bar can satisfy the essential strength and other characteristics required for a concrete structure. In addition, it is useful for various special buildings that take advantage of its characteristics in place of iron and steel. Examples include large bridges, berths, pier decks,
As cables for various concrete structures such as linear motor car rail girder, concrete reinforcing bars or tendons are used at the foundation of buildings such as nuclear magnetic resonance equipment building, earth simulator (ultra-high speed parallel computer system), proton accelerator facility, fusion reactor facility, etc. It is constructed as.

[0022]

The present invention will be specifically described below with reference to examples.

Examples 1 and 2 Aramid filaments (Kevlar 4 manufactured by Du Pont-Toray Co., Ltd.)
9) Aligned, braided into a 9 mm diameter braid, impregnated with low-viscosity liquid bisphenol A / aliphatic amine resin at room temperature, cured at 150 ° C. for 10 minutes to obtain a braid-shaped 1 m long rod Made. Under the same conditions, a cured piece of only resin was prepared, and Tg was 145 ° C. The surface of the first rod is impregnated with a tetraglycidylaminodiphenylmethane-based epoxy resin containing 4,4′-diaminodiphenylsulfone as a curing agent (Sumi-Epoxy ELM-434 manufactured by Sumitomo Chemical Co., Ltd .; glass transition point 230 ° C.) The composition was cured at 180 ° C. for 1 hour to form a coating layer having a thickness of 0.5 mm to obtain a target bar (Example 1). After placing the second rod concentrically at the center of the cylindrical mold of the injection molding machine and closing the mold, 200 ml of polyether sulfone resin (SUMIKAEXCEL PES3600G manufactured by Sumitomo Chemical Co., Ltd .; glass transition point 225 ° C.) was used. The mixture was heated and fluidized at a temperature of 0 ° C., injected into a mold from a nozzle, and coated with resin around the rod to obtain a rod having a heat-resistant coating layer having a thickness of 0.5 mm (Example 2).

The rods obtained in Examples 1 and 2 and the third
Using an uncoated rod, the tensile strength-heating temperature relationship (cold) and the tensile strength-heating temperature relationship (hot) were determined.
The results are shown in FIGS. □, お よ び, and × indicate the results of the bar of Example 1, the bar of Example 2, and the uncoated rod, respectively. The cold tensile strength test is a test in which a test object is heated at a predetermined temperature for 10 minutes and then subjected to a tensile loading (loading speed of 600 Mpa / min) while being cooled to room temperature (25 ° C.). Is a test in which a test object is heated to a predetermined temperature (heating rate: 2 ° C./min), and tensile loading (loading speed: 600 Mpa / min) is performed while maintaining the predetermined temperature. In the same manner, for the rod material of Example 1 and the uncoated rod, the concrete adhesion retention ratio (hot) was obtained, and the results shown in FIG. 3 were obtained. Similarly, the broken line shows the results for the bar of Example 1, and the solid line shows the results for the uncoated rod.

[0025]

According to the present invention, a fiber reinforced plastic made of a high-performance continuous fiber reinforced material having excellent unique properties such as high specific strength, non-conductivity, and non-magnetism is used as a core material. The present invention also relates to a bar as a concrete reinforcing material or a tendon material coated with a heat-resistant resin having a glass transition point higher than 20 ° C. It was found that the assumed excellent heat resistance was secured. Not only as cables for various types of civil engineering and building structures, but also by utilizing its unique characteristics, it is used as a reinforcing material or tension member for concrete members used in buildings such as nuclear magnetic resonance equipment, tokamak fusion reactor facilities, and computer centers. Useful as In particular, in the latter building and other construction fields, if the heat resistance and fire resistance are further secured, it is expected that various applications will be opened in the future. The present invention is a starting point.

[Brief description of the drawings]

FIG. 1 shows the relationship between tensile strength and heating temperature (cold) of the bar of Example 1, the bar of Example 2, and an uncoated rod.

FIG. 2 shows the relationship between tensile strength and heating temperature (hot) of the bar of Example 1, the bar of Example 2, and an uncoated rod.

FIG. 3 shows the relationship between the retention of the adhesive force between the bar of Example 1 and the concrete of the uncoated rod and the heating temperature (hot).

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Claims (6)

[Claims] 1. A rod formed from a fiber-reinforced plastic composite material made of continuous fibers, having a glass transition point higher by at least 20 ° C. than the glass transition point of a matrix resin constituting the composite material over the entire surface thereof. A fiber reinforced plastic bar excellent in heat resistance, characterized by being coated with a heat resistant resin layer having the same. 2. The continuous fiber is a fiber selected from aramid fiber, acrylonitrile-based carbon fiber, glass fiber, and poly-p-phenylene benzobisoxazole fiber, and the matrix resin is a phenolic epoxy resin, a vinyl ester resin, and an unsaturated resin. The fiber reinforced plastic rod according to claim 1, which is a resin selected from polyester resins. 3. The heat-resistant resin layer is made of aromatic amino epoxy resin, polyether sulfone, phenylene bis-
The fiber reinforced plastic rod according to claim 1 or 2, comprising a resin selected from a crosslinked polyaminoamide resin of 1,3-oxazole and an aromatic diamine. 4. The glass transition point of the matrix resin is 18
0 ° C. or less, and the glass transition point of the heat-resistant resin is 200 ° C.
The fiber reinforced plastic bar according to any one of claims 1 to 3, which is as described above. 5. The bar according to claim 1, which is used as a concrete reinforcing material or a prestressed concrete tendon. 6. The fiber-reinforced plastic bar according to claim 5, which is used as a concrete reinforcing material or a prestressed tendon for a building for equipment requiring a strong magnetic field, a strong electric field, and non-conductivity.