KR102543358B1 - Fast curing epoxy resin composition and fiber reinforced plastic using the same - Google Patents

Abstract

The fiber-reinforced plastic according to the present invention includes a bifunctional epoxy, a trifunctional epoxy, and a tetrafunctional epoxy, an acid anhydride-based compound, a long-chain alkyl alcohol, a fatty acid, and a curing accelerator, and the ratio of the bifunctional, trifunctional, and tetrafunctional epoxy is 1 :1:8 to 1:2:7 composed of a fast-curing epoxy resin composition and carbon fiber. Such a fast-curing epoxy resin composition according to the present invention and fiber-reinforced plastic using the same can have tensile strength, glass transition temperature and flexibility required for transmission and transmission lines at the same time, and can improve the existing poor appearance by having excellent appearance. . Accordingly, it is possible to achieve technological progress in the field through lower weight, flexibility and excellent appearance compared to conventional aluminum cable cores.

Description

Fast-curing epoxy resin composition and fiber-reinforced plastic using the same

The present invention relates to an epoxy resin composition having fast curing properties and a fiber-reinforced plastic manufactured using the same, and relates to a fast-curing epoxy resin composition having a fast curing speed, high heat resistance and flexibility at the same time, and a fiber-reinforced plastic manufactured using the same. It's about plastic.

In general, epoxy resin compositions are widely used as matrix resins for producing fiber-reinforced plastics, and fiber-reinforced plastics manufactured using epoxy resin compositions and carbon fibers are, for example, dry-type transformers, gas-insulated switchgear and electric cables, etc. It is used extensively in electrical infrastructure. In the past decade, fiber-reinforced plastics using epoxy resin compositions have been used for electrical transmission, especially new types of overhead cables.

A conventional overhead cable uses a steel core aluminum stranded overhead cable in which aluminum alloy conductors are stranded in order to maintain high tensile strength. Since the steel core aluminum stranded overhead line used as an overhead transmission line has a large self-load, line sagging occurs. To solve this problem, when manufacturing a stranded overhead line, a fiber-reinforced plastic (composite) core based on an epoxy resin composition is applied In this case, it is possible to provide many advantages over conventional cores, such as lower line sag than aluminum cores, light weight, low thermal expansion coefficient, and high operating temperature. As such, a representative example of a fiber-reinforced plastic core based on an epoxy resin composition is a carbon fiber-reinforced plastic core manufactured by impregnating carbon fiber with an epoxy resin composition and then performing pultrusion.

The fiber-reinforced plastic core containing these carbon fibers should have characteristics that increase the transmission capacity of the cable without causing line sag due to load, and should have high tensile strength and high heat resistance. In addition, since the cable has to be wound around drums and wheels due to its nature, it is necessary to have a certain level of flexibility. However, improving high heat resistance and flexibility at the same time is a very difficult technical task because they have a conflicting relationship with each other due to their characteristics.

Currently used cable composite cores are manufactured by impregnating carbon fibers with an epoxy resin composition containing an alicyclic epoxy resin blended with a bisphenol-A epoxy resin and/or a novolak epoxy resin. However, these cable composite cores have a problem in that they do not sufficiently achieve the performance required of the cable composite core because the glass transition temperature is low and the tensile strength is lower than 2,800 MPa.

In addition, in the case of the conventional fast-curing epoxy resin, the curing speed is fast, but there is a problem in that the appearance is not excellent and ashy is generated when manufacturing the composite material (during pultrusion).

Korean Patent Publication No. 10-2019-0042171

The present invention has been made to solve the above problems, and the problem to be solved by the present invention is to have a high glass transition temperature, high elongation, and excellent appearance so that it can be used in the core of an overhead transmission line, It is to provide a fast-curing epoxy resin composition capable of improving workability and productivity and a fiber-reinforced plastic using the same.

The above and other objects and advantages of the present invention will become apparent from the following description of preferred embodiments.

The above object is a fast-curing epoxy resin composition comprising bifunctional epoxies, trifunctional epoxies and tetrafunctional epoxies, wherein the ratio of bifunctional, trifunctional and tetrafunctional epoxies is 1: 1: 8 to 1: 2: 7 is achieved

Preferably, the fast-curing epoxy resin composition may further include an acid anhydride-based compound, a long-chain alkyl alcohol, a fatty acid, and a curing accelerator.

Preferably, 150 to 170 parts by weight of an acid anhydride-based compound, 8 to 10 parts by weight of a long-chain alkyl alcohol, 1 to 2 parts by weight of a fatty acid and It may contain 4 to 6 parts by weight of a curing accelerator.

Preferably, the long-chain alkyl alcohols and fatty acids may be in liquid form.

Preferably, the viscosity of the fast-curing epoxy resin composition may be 1,500 or more and less than 3,000 cps at 25°C.

In addition, the above object includes a cured epoxy resin product formed by curing carbon fiber and a fast-curing epoxy resin composition, and the fast-curing epoxy resin composition is a fiber-reinforced plastic including a bifunctional epoxy, a trifunctional epoxy, and a tetrafunctional epoxy. is achieved by

Preferably, the fast-curing epoxy resin composition may have a ratio of 2-, 3- and 4-functional epoxies of 1:1:8 to 1:2:7.

Preferably, the fast-curing epoxy resin composition may further include an acid anhydride-based compound, a long-chain alkyl alcohol, a fatty acid, and a curing accelerator.

Preferably, the fast-curing epoxy resin composition contains 150 to 170 parts by weight of an acid anhydride compound, 8 to 10 parts by weight of a long-chain alkyl alcohol, fatty acids, based on 100 parts by weight of epoxy including bifunctional epoxy, trifunctional epoxy and tetrafunctional epoxy. It may include 1 to 2 parts by weight and 4 to 6 parts by weight of the curing accelerator.

Preferably, the long-chain alkyl alcohols and fatty acids may be in liquid form.

Preferably, the cured epoxy resin material may have a glass transition temperature of 200 to 210 °C.

Preferably, the fiber-reinforced plastic may have an elongation of 1.8 to 2.0%.

Preferably, the fiber-reinforced plastic may include 60 to 70% by weight of carbon fiber and 30 to 40% by weight of a cured epoxy resin material.

Preferably, the fiber-reinforced plastic may have a tensile strength of 2,800 MPa or more.

Preferably, the fiber-reinforced plastic has a density of 1.63±3% g/cm ³ .

Preferably, the carbon fibers may have a diameter of 4 to 11 μm.

Preferably, the cured epoxy resin material may not generate an unreacted peak according to DSC analysis when cured at 180 to 210° C. for 10 to 30 minutes.

Preferably, the viscosity of the fast-curing epoxy resin composition may be 1,500 to 3,000cps.

Preferably, the fast-curing epoxy resin composition may have a curing speed of 30 to 90 seconds under the conditions of 5ml and 200°C.

The fiber-reinforced plastics described above can be used to manufacture wire cores constituting central tension lines for overhead transmission lines.

In addition, the above object is the first step of preparing the above-described fast-curing epoxy resin composition, the second step of drawing the continuous carbon fiber into a tank filled with the fast-curing epoxy resin composition, and impregnating the carbon fiber with the fast-curing epoxy resin composition. A third step of making, a fourth step of drawing the carbon fiber impregnated with the fast-curing epoxy resin composition through a heated die to produce a viscous carbon fiber tow, and a fifth step of additionally drawing the viscous carbon fiber tow. It is achieved by a method for producing fiber-reinforced plastics.

Preferably, the fifth step of further drawing the viscous carbon fiber tow may be to draw the viscous carbon fiber tow toward a post-curing dryer at 200 to 220 ° C. at a drawing speed of 300 mm / min in the longitudinal direction of the die. .

The fast-curing epoxy resin composition and fiber-reinforced plastic using the same according to the present invention can simultaneously have tensile strength, glass transition temperature and flexibility required for transmission and transmission lines, and can improve the existing poor appearance by having excellent appearance. Accordingly, it has an effect of making technological progress in the field through lower weight, flexibility and excellent appearance compared to conventional aluminum cable cores.

In addition, the fast-curing epoxy resin composition according to the present invention and the fiber-reinforced plastic using the same can improve workability and productivity in a pultrusion molding process.

However, the effects of the present invention are not limited to the effects mentioned above, and other effects not mentioned will be clearly understood by those skilled in the art from the description below.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. In case of conflict, the present specification, including definitions, will control. Also, although methods and materials similar or equivalent to those described herein may be used in the practice or testing of the present invention, suitable methods and materials are described herein.

A fiber-reinforced plastic according to an embodiment of the present invention includes carbon fiber and a cured epoxy resin material.

In one embodiment, the cured epoxy resin material is a matrix resin included in fiber-reinforced plastic, and is a cured fast-curing epoxy resin composition. In this case, the fast-curing epoxy resin composition includes a bifunctional epoxy, a trifunctional epoxy, and a tetrafunctional epoxy, and further includes an acid anhydride-based curing agent, a long-chain alkyl alcohol, a fatty acid, and a curing accelerator. Such a cured epoxy resin material can be used for pultrusion, and can simultaneously realize flexibility while having a glass transition temperature of 200° C. or higher for use in overhead transmission lines.

In one embodiment, the epoxy included in the fast-curing epoxy resin composition is a multifunctional epoxy resin having an average of more than two epoxy groups per molecule among resins having two or more epoxy groups in one molecule. Multifunctional epoxy resin is a thermosetting resin with excellent electrical insulating properties, heat resistance and chemical stability. More specifically, epoxy resins include bifunctional epoxies, trifunctional epoxies and tetrafunctional epoxies.

As the bifunctional epoxy resin, it is preferable to use a bifunctional epoxy resin such as a bisphenol F type epoxy resin or a bisphenol A type epoxy resin, and in particular, a bisphenol A type epoxy resin is preferred, but is limited thereto It is not.

Further, in the present invention, the fast-curing epoxy resin composition includes trifunctional and tetrafunctional epoxies as other epoxy resin components in addition to the bifunctional epoxy.

Here, the trifunctional epoxy resin preferably has three epoxy groups directly or indirectly substituted at the meta position on the phenyl ring in the backbone of the compound, and the tetrafunctional epoxy resin is directly at the meta position on the phenyl ring in the backbone of the compound. It is preferred to have four epoxy groups substituted with or indirectly.

Trifunctional epoxy resins include phenol and cresol epoxy novolacs, glycidyl ethers of phenol-aldehyde adducts, aromatic epoxies, dialiphatic triglycidyl ethers, aliphatic polyglycidyl ethers, epoxidized olefins, brominated resins, triglycerides. It is preferable to include at least one selected from cydyl aminophenyl, aromatic glycidyl amine, heterocyclic glycidyl imidine and amide, glycidyl ether and fluorinated epoxy or a mixture thereof. In particular, the trifunctional epoxy resin is preferably triglycidylaminophenol (TGA), but is not limited thereto.

Tetrafunctional epoxy resins include phenol and cresol epoxy novolacs, glycidyl ethers of phenol-aldehyde adducts, aromatic epoxy resins, aliphatic triglycidyl ethers, dialiphatic triglycidyl ethers, aliphatic polyglycidyl at least one selected from ethers, epoxidized olefins, brominated resins, triglycidyl aminophenyls, aromatic glycidyl amines, heterocyclic glycidyl imidines and amides, glycidyl ethers and fluorinated epoxy resins; or It is preferred to include resins based on any combination of these. In particular, the tetrafunctional epoxy resin is N,N,N',N'-tetraglycidyl-m-xylenediamine or 4,4'-tetraglycidyldiaminodiphenylmethane (4,4'-tetraglycidyl diaminodiphenyl Methane (TGDDM) is preferred, but not limited thereto.

As such, the ratio of the bifunctional epoxy, trifunctional epoxy and tetrafunctional epoxy constituting the fast curing epoxy resin composition is preferably 1:1:8 to 1:2:7. If the ratio of tetrafunctional epoxy is greater than 8 and the ratio of trifunctional epoxy is less than 1, the elongation decreases, ash is generated on the exterior, and the viscosity increases. If the ratio exceeds 2, the glass transition temperature is low and the tensile strength is low. As described above, if the bifunctional epoxy, trifunctional epoxy, and tetrafunctional epoxy constituting the fast-curing epoxy resin composition do not satisfy the above ratio, physical properties required when used as a cable core cannot be achieved.

In one embodiment, the acid anhydride-based compound used as the curing agent is selected from among methyl tetrahydrophthalic anhydride (MTHPA), tetrahydrophthalic anhydride (THPA), hexahydrophthalic anhydride (HHPA) and nadic methyl anhydride (NMA). It is preferable to include any one selected or a mixture of two or more. In particular, the acid anhydride-based compound is preferably nadic methyl anhydride (NMA), but is not limited thereto.

In addition, the acid anhydride-based compound is preferably included in an amount of 150 to 170 parts by weight based on 100 parts by weight of epoxy including bifunctional epoxy, trifunctional epoxy and tetrafunctional epoxy. If the content of the acid anhydride-based compound is less than 150 parts by weight, heat resistance is lowered due to the formation of unreacted epoxy in the pultrusion process, which is undesirable. This is because it is undesirable because it lowers physical properties.

In the present invention, it is preferable that the acid anhydride-based curing agent is used alone. When an amine-based curing agent is used, it is not suitable for a process that requires curing in a short time due to the characteristics of the pultrusion molding process, and by-products may be generated from crosslinking of polymers through an addition reaction with an acid anhydride-based curing agent.

In one embodiment, the fast-curing epoxy resin composition may include long-chain alkyl alcohols and fatty acids, and these components function to remove unreacted materials and impart flexibility. That is, long-chain alkyl alcohols and fatty acids perform a chain reaction to cure 100% of the fast-curing epoxy resin composition, thereby preventing unreacted substances from being generated in the fast-curing epoxy resin composition. At this time, the long-chain alkyl alcohol and fatty acid are preferably in liquid form. Since long-chain alkyl alcohols and fatty acids have a liquid form and do not use a separate solvent, the process of removing the solvent can be omitted and the process cost can be reduced.

These long-chain alkyl alcohols are monoalcohol compounds having 8 to 32 carbon atoms, such as octanol, nonanol, decanol, undecanol, dodecanol, tridecanol, tetradecanol, pentadecanol, and hexadecane. Ol, heptadecanol, octadecanol, nonadecanol, icosanol, heicosanol, docosanol, trichosanol, tetracosanol, pentacosanol, hexacosanol, heptacosanol, octacosanol, nonacosanol , straight-chain or branched alcohols such as triacontanol, hentriacontanol, and dotriacontanol. In particular, the long-chain alkyl alcohol is preferably octanol, but is not limited thereto.

In this case, the long-chain alkyl alcohol is preferably included in an amount of 8 to 10 parts by weight based on 100 parts by weight of epoxy including bifunctional epoxy, trifunctional epoxy and tetrafunctional epoxy. If the content of the long-chain alkyl alcohol is less than 8 parts by weight, unreacted substances are formed and the appearance deteriorates, and if it exceeds 10 parts by weight, the glass transition temperature is lowered and the overall physical properties are deteriorated. Through this, it is possible to prevent a decrease in physical properties that occurs when the content of any one of the long-chain alkyl alcohol and the epoxy is excessive and achieve the required physical properties.

In addition, fatty acids include myristoleic acid, palmitoleic acid, sapienic acid, oleic acid, elaidic acid, vaccenic acid, linoleic acid, linoelaidic acid, α-linolenic acid, arachidonic acid, eicosapentaenoic acid, erucic acid or docosa. It may be at least one of hexaenoic acids. In particular, the fatty acid is preferably oleic acid, but is not limited thereto.

At this time, it is preferable to include 1 to 2 parts by weight of the fatty acid based on 100 parts by weight of the epoxy including bifunctional epoxy, trifunctional epoxy and tetrafunctional epoxy. When the fatty acid content is less than 1 part by weight, unreacted materials are present during curing, and when it is greater than 2 parts by weight, the glass transition temperature is lowered and the overall physical properties are lowered.

On the other hand, in the case of conventional epoxy resin compositions, appearance defects such as ashy are generated during pultrusion, which is caused by uncured materials confirmed through DSC measurement, and the fast-curing epoxy resin composition according to the present invention By adding long-chain alkyl alcohols and fatty acids, the uncured portion is solved and an excellent appearance is expressed. More specifically, when the cured epoxy resin material according to the present invention is cured at 180 to 210° C. for 10 to 30 minutes, no unreacted peak according to DSC analysis is generated.

In addition, the curing accelerator is preferably included in an amount of 4 to 6 parts by weight based on 100 parts by weight of epoxy including bifunctional epoxy, trifunctional epoxy and tetrafunctional epoxy. When the curing accelerator is less than 4 parts by weight, the curing time of the fast-curing epoxy resin composition increases, and when it exceeds 6 parts by weight, the glass transition temperature decreases without improving physical properties or shortening the curing time.

In the present invention, the curing accelerator preferably includes an imidazole-based curing accelerator. This is because, in the case of urea-based curing accelerators and tertiary amine-based curing accelerators, when used in the present invention, the curing speed tends to decrease or the crosslinking density tends to decrease.

In one embodiment, the viscosity of the fast-curing epoxy resin composition is preferably 1,500 to 3,000 cps at 25 ° C based on the ASTM-D2983 test for excellent pultrusion processability, and to increase the impregnation between the carbon fiber and the epoxy resin. It is more preferable that it is 1,500 to 2,800 cps for this. If the viscosity is less than 1,500cps, the viscosity is too low and flowability increases, resulting in the impregnated resin coming out again by tension, and if it exceeds 3,000cps, there is a problem of lowering the impregnation between the carbon fiber and the epoxy resin. . Conventionally, in order to lower the viscosity of the resin, a method of artificially lowering the viscosity by installing a separate warming device that increases the temperature in the pultrusion molding impregnation tank is used, but in this case, the stability over time of the cured resin is lowered, causing a decrease in productivity. Therefore, the fast-curing epoxy resin composition according to the present invention adjusts the viscosity to 1,500 to 3,000cps, so it does not use a separate warming device, so it has excellent stability over time and high impregnation between carbon fiber and epoxy resin when manufacturing fiber-reinforced plastics. there is

In one embodiment, the fast-curing epoxy resin composition preferably has a curing speed of 30 to 90 seconds under the conditions of 5ml and 200°C. At this time, if the curing speed is less than 30 seconds, it hardens quickly during pultrusion, causing clogging in the mold, and also causes a problem of curing before impregnation. .

Fiber-reinforced plastic according to an embodiment of the present invention includes a cured epoxy resin material and carbon fiber. In this case, the cured epoxy resin material is obtained by curing the above-described fast-curing epoxy resin composition, and carbon fibers are impregnated with the fast-curing epoxy resin composition and then cured to prepare a fiber-reinforced plastic.

In one embodiment, the fiber-reinforced plastic preferably includes 60 to 70% by weight of carbon fiber and 30 to 40% by weight of a cured epoxy resin material. At this time, if the carbon fiber content is less than 60% by weight or the content of the cured epoxy resin material exceeds 40% by weight, the required performance of the composite material cannot be achieved, and the carbon fiber content exceeds 70% by weight or the content of the cured epoxy resin material is 30% by weight. If it is less than the weight percent, the binding force between the carbon fibers is lowered and the physical properties of the composite material are lowered.

In one embodiment, the glass transition temperature of the cured epoxy resin material is preferably 200 to 210 °C. If the glass transition temperature is less than 200 ° C, deformation occurs because it cannot withstand high temperatures when manufactured as an overhead transmission line, and if it exceeds 210 ° C, unnecessary costs are incurred, which is not preferable.

In one embodiment, it is preferable that the diameter of the carbon fiber is 4 to 11 μm. These carbon fibers have axes aligned in the longitudinal direction of the fiber-reinforced plastic, and it is preferable to manufacture the fiber-reinforced plastic through pultrusion.

In one embodiment, the elongation of the fiber-reinforced plastic is preferably 1.8 to 2.0%. At this time, if the elongation of the fiber-reinforced plastic is less than 1.8%, it is difficult to exhibit the inherent properties of the carbon fiber, resulting in a decrease in physical properties.

In one embodiment, the fiber-reinforced plastic preferably has a tensile strength of 2,800 MPa or more as measured by the ASTM D3039-08 test. If the tensile strength is less than 2,800 MPa, the overhead transmission line has a problem of being damaged by its own load and external force when used as a core for an overhead transmission line.

In one embodiment, the fiber-reinforced plastic has a density of 1.63±3% g/cm ³ It is preferable.

As described above, the fast-curing epoxy resin composition according to the present invention has increased elongation and high glass transition temperature (Tg) without deteriorating the minimum winding diameter when manufactured from fiber-reinforced plastic containing carbon fibers, and has excellent appearance during molding. provides an advantage In addition, the fiber-reinforced plastic according to an embodiment of the present invention satisfies the glass transition temperature (Tg) and elongation as described above. Therefore, the above-mentioned fiber-reinforced plastics including carbon fibers and cured epoxy resins prevent damage when winding on bobbins, drums, pulleys, wheels, etc. during manufacturing, manufacturing or erection processes as central tension lines (overhead transmission line wire cores) of overhead transmission lines. It has the flexibility to be restrained.

A method for manufacturing a fiber-reinforced plastic according to another embodiment of the present invention includes a first step of preparing a fast-curing epoxy resin composition, a second step of drawing continuous carbon fibers into a tank filled with the fast-curing epoxy resin composition, and a fast-curing epoxy resin composition. The third step of impregnating the carbon fiber with the resin composition, the fourth step of drawing the carbon fiber impregnated with the fast-curing epoxy resin composition through a heated die to produce a viscous carbon fiber tow, and further drawing toward a post-curing dryer Step 5 is included.

First, in the first step of preparing a fast-curing epoxy resin composition, an epoxy resin in which a bifunctional epoxy, a trifunctional epoxy, and a tetrafunctional epoxy is mixed, an acid anhydride-based compound, a long-chain alkyl alcohol, a fatty acid, and a curing accelerator are mixed. At this time, since the detailed configuration and physical properties of the fast-curing epoxy resin composition are the same as those described above, a detailed description thereof will be omitted.

Next, in the second step of drawing the continuous carbon fiber into the tank filled with the fast-curing epoxy resin composition and the third step of impregnating the carbon fiber with the fast-curing epoxy resin composition, the fast-curing epoxy resin composition prepared in the first step After filling the tank, carbon fibers are drawn into the filled tank, and the carbon fibers are impregnated with the fast-curing epoxy resin composition. At this time, it is preferable to satisfy 60 to 70% by weight of carbon fiber and 30 to 40% by weight of cured epoxy resin material with respect to the fast-curing epoxy resin composition impregnated into carbon fiber, and to remove excessively impregnated fast-curing epoxy resin composition. do.

Next, in the fourth step of drawing the carbon fiber impregnated with the fast-curing epoxy resin composition through a heated die to produce a viscous carbon fiber tow, the viscous carbon fiber tow is primarily cured through a die heated to 170 to 190 ° C. Manufactures fiber tow.

Finally, in the fifth step of additional drawing toward the post-curing dryer, the viscous carbon fiber tow primarily cured in the fourth step is additionally drawn toward the post-curing dryer at a temperature of 200 to 220 ° C to produce fiber-reinforced plastic. . At this time, the drawing speed is preferably 300 mm/min, and the drawing direction is preferably parallel to the longitudinal direction of the die.

Hereinafter, the configuration of the present invention and its effects will be described in more detail through Examples and Comparative Examples. However, these examples are for explaining the present invention in more detail, and the scope of the present invention is not limited to these examples.

[Example]

[Example 1-6]

Bifunctional epoxy bisphenol A (BPA, product name: YD-128, Kukdo Chemical), trifunctional epoxy triglycidylaminophenol (TGA, product name: KDS-8805, Kukdo Chemical), tetrafunctional epoxy 4,4'-tetraglycy 4,4'-tetraglycidyl diaminodiphenyl methane (TGDDM, trade name: PA-806L), acid anhydride curing agent Nadicmethylanhydride (NMA), long-chain alkyl alcohol (Octanol, Sigma-Aldrich Co.), An epoxy resin composition was prepared by mixing a fatty acid (Oleic acid, Sigma-Aldrich Co.) and an imidazole catalyst (trade name: 1B2MZ, SHIKOKU Co.) as a curing accelerator in the ratio shown in Table 1 and then stirring.

Next, the prepared epoxy resin composition is filled in a tank, and a carbon fiber tow (T700S, Toray Co., diameter 10.5 μm) having a standard modulus is drawn into the tank, and the epoxy resin composition in the tank is impregnated into the carbon fiber tow, Excess epoxy resin composition is removed from the carbon fibers at the outlet of the tank. Next, the resin-impregnated carbon fiber tow is drawn and cured through a die heated to 180 ° C to produce a viscous carbon fiber tow, which is further drawn toward a post-curing dryer at 210 ° C to produce a fiber-reinforced plastic did At this time, the carbon fiber tow was drawn parallel to the longitudinal direction of the die at a drawing speed of 300 mm/min. The diameter (D) of the fiber-reinforced plastic thus formed was 10 mm, and the fiber-reinforced plastic was prepared so that the content of carbon fiber in the fiber-reinforced plastic was 70% by weight.

[Comparative Example 1-9]

A fiber-reinforced plastic was prepared in the same manner as in Example 1, except that the epoxy resin composition was prepared as shown in Tables 2 and 3.

For the epoxy resin compositions and fiber-reinforced plastics prepared in Examples 1 to 6 and Comparative Examples 1 to 9, physical properties were evaluated through the following experimental examples, and the results are shown in Tables 1 to 3.

[Experimental Example]

(1) Viscosity measurement

The viscosity of the epoxy resin compositions prepared according to Examples 1 to 6 and Comparative Examples 1 to 9 was measured at 25° C. according to ASTM D-2983.

(2) Measurement of glass transition temperature (Tg)

After curing the epoxy resin compositions prepared according to Examples 1 to 6 and Comparative Examples 1 to 9, the glass transition temperature (Tg) was measured through dynamic mechanical analysis (DMA) according to ASTM D7028-O7e1.

(3) Measurement of tensile elongation

ASTM D3039-08 test on fiber-reinforced plastics prepared according to Examples 1 to 6 and Comparative Examples 1 to 9 (sample length: 1 m, test speed: 5 mm per minute (mm/min), gauge length: 50 cm) Tensile elongation was measured according to.

(4) Curing time measurement

For the epoxy resin compositions prepared in Examples 1 to 6 and Comparative Examples 1 to 9, an amount of 5 ml was cured under a hot plate condition of 200 ° C. to confirm the time when the curing of the epoxy resin composition was completed, The curing time (gel time) was measured.

(5) Measurement of tensile strength

The tensile strength of the fiber-reinforced plastics prepared according to Examples 1 to 6 and Comparative Examples 1 to 9 was measured according to the ASTM B987 test.

(6) DSC analysis

After curing the epoxy resin composition prepared according to Examples 1 to 6 and Comparative Examples 1 to 9 at 200 ° C. for 20 minutes, a sample of 5 mg was taken and subjected to DSC analysis (DSC) while raising the temperature from room temperature to 350 ° C. at 10 ° C. per minute. -Q2000 V24.10) was used to confirm unreacted peaks based on the following criteria.

X: no unreacted peak

○: 1 or more unreacted peaks

(7) Appearance observation

The appearance of the fiber-reinforced plastics prepared according to Examples 1 to 6 and Comparative Examples 1 to 9 was visually observed to confirm the presence of ashes based on the following criteria.

○: ashy not observed

X: Observe ashy

evaluation item Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Tetrafunctional Epoxy (TGDDM) 80 70 80 80 80 80 Trifunctional Epoxy (TGA) 10 20 10 10 10 10 Bifunctional Epoxy (BPA) 10 10 10 10 10 10 Acid anhydride compound (NMA) 170 170 150 170 170 170 imidazole-based catalyst 4 4 4 4 4 6 long-chain alkyl alcohol 10 10 10 8 10 10 fatty acid 2 2 2 2 One 2 Glass transition temperature (℃) 203 201 200 202 200 201 Elongation (%) 1.90 1.88 1.87 1.88 1.81 1.86 180℃ curing time (Sec) 53 51 59 54 55 55 Unreacted peak (DSC) X X X X X X Exterior ○ ○ ○ ○ ○ ○ Viscosity at 25°C (cps) 2620 2410 2843 2622 2610 2631 CFRP tensile strength (Mpa) 2865 2840 2800 2810 2826 2834

evaluation item Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Tetrafunctional Epoxy (TGDDM) 80 90 60 80 80 Trifunctional Epoxy (TGA) 10 5 20 10 10 Bifunctional Epoxy (BPA) 10 5 20 10 10 Acid anhydride compound (NMA) 170 170 170 170 170 imidazole-based catalyst 4 4 4 4 4 long chain alkyl alcohol - 10 10 7 11 fatty acid - 2 2 2 2 Glass transition temperature (℃) 210 216 190 205 196 Elongation (%) 1.86 1.75 1.83 1.81 1.82 180℃ curing time (Sec) 53 55 59 54 53 Unreacted peak (DSC) ○ ○ ○ ○ X Exterior X X X X ○ Viscosity at 25°C (cps) 2690 3210 2480 2632 2608 CFRP tensile strength (Mpa) 2850 2923 2756 2820 2710

evaluation item Comparative Example 6 Comparative Example 7 Comparative Example 8 Comparative Example 9 Bifunctional Epoxy (BPA) 80 80 80 80 Trifunctional Epoxy (TGA) 10 10 10 10 Tetrafunctional Epoxy (TGDDM) 10 10 10 10 Acid anhydride compound (NMA) 170 170 145 175 imidazole-based catalyst 4 4 4 4 long chain alkyl alcohol 10 10 10 10 fatty acid 0.5 3 2 2 Glass transition temperature (℃) 204 192 193 202 Elongation (%) 1.83 1.76 1.78 1.72 180℃ curing time (Sec) 53 56 59 53 Unreacted peak (DSC) ○ X X X Exterior X ○ ○ ○ Viscosity at 25°C (cps) 2620 2611 3011 2581 CFRP tensile strength (Mpa) 2820 2824 2722 2730

As shown in Table 1 above, Examples 1 to 6 according to the present invention all have a tensile strength of 2,800 MPa or more, a glass transition temperature of 200 ° C or more, an elongation of 1.8% or more, a curing time of 30 to 90 seconds, In addition, as a result of the DCS evaluation, it can be seen that no unreacted peak is generated, no ash is generated on the exterior, and both viscosity and tensile strength satisfy the conditions required for the cable composite core.

On the other hand, as shown in Tables 2 and 3, Comparative Example 1, in which long-chain alkyl alcohols and fatty acids were not used when preparing the epoxy resin composition, had a DSC unreacted peak, resulting in unreacted ash. You can see there is a problem.

In addition, in Comparative Example 2, in which the bifunctional epoxy is excessive and the trifunctional and tetrafunctional epoxy is insufficient, the elongation is low and some unreacted peaks appear, resulting in ash generation and excessive viscosity.

In addition, it can be seen that in Comparative Example 3, in which the bifunctional epoxy is insufficient and the tetrafunctional epoxy is excessive, the glass transition temperature is low and some unreacted peaks appear, causing ash to occur on the appearance and lowering the tensile strength.

In addition, it can be seen that Comparative Example 4, which lacks long-chain alkyl alcohol, has unreacted peaks and appearance problems in DSC.

In addition, Comparative Example 5 containing an excessive amount of long-chain alkyl alcohol rather lowered the crosslinking density of epoxy, and it can be seen that the physical properties of CFRP were deteriorated.

In addition, it can be seen that Comparative Example 6, which lacks fatty acids, has a problem in appearance because it does not participate in the reaction.

In addition, in Comparative Example 7 with excessive fatty acids, it can be seen that excessive fatty acids act as impurities and deteriorate the physical properties of CFRP.

In addition, in Comparative Example 8 lacking an acid anhydride-based compound, it can be seen that the epoxy curing reaction did not fully occur, resulting in a decrease in glass transition temperature (TG), deterioration in physical properties of CFRP, and an increase in viscosity.

In addition, in Comparative Example 9, in which the acid anhydride-based compound was excessive, it can be seen that the acid anhydride-based compound that did not participate in the reaction remained and the physical properties of CFRP deteriorated.

As such, Comparative Examples 1 to 9, which do not satisfy the configuration of the present invention, sometimes show a high glass transition temperature of 200 ° C. or more, but in some cases cannot satisfy the elongation of 1.8% or more for use as an overhead transmission line core. You can check. In addition, the tensile strength of fiber-reinforced plastics is affected by the ratio between carbon fiber and the epoxy resin composition, and the higher the content of carbon fiber, the higher the tensile strength, but since the manufacturing cost increases, the optimal content according to the purpose need this

Although the preferred embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements of those skilled in the art using the basic concept of the present invention defined in the following claims are also made according to the present invention. falls within the scope of the rights of

Claims (21)

A bifunctional epoxy, a trifunctional epoxy, a tetrafunctional epoxy, an acid anhydride-based compound, a long chain alkyl alcohol, a fatty acid, and a curing accelerator,
The ratio of the bifunctional, trifunctional and tetrafunctional epoxies is 1: 1: 8 to 1: 2: 7,
150 to 170 parts by weight of the acid anhydride-based compound, 8 to 10 parts by weight of the long-chain alkyl alcohol, 1 to 2 parts by weight of the fatty acid, and A fast-curing epoxy resin composition comprising 4 to 6 parts by weight of the curing accelerator. delete delete According to claim 1,
The long-chain alkyl alcohol and the fatty acid are in liquid form, a fast-curing epoxy resin composition. According to claim 1,
The fast-curing epoxy resin composition has a viscosity of 1,500 to 3,000 cps at 25 ° C., a fast-curing epoxy resin composition. carbon fiber; and
a cured epoxy resin product formed by curing a fast-curing epoxy resin composition;
including,
The fast-curing epoxy resin composition includes a bifunctional epoxy, a trifunctional epoxy and a tetrafunctional epoxy, an acid anhydride-based compound, a long-chain alkyl alcohol, a fatty acid, and a curing accelerator,
The ratio of the bifunctional, trifunctional and tetrafunctional epoxies is 1: 1: 8 to 1: 2: 7,
150 to 170 parts by weight of the acid anhydride-based compound, 8 to 10 parts by weight of the long-chain alkyl alcohol, 1 to 2 parts by weight of the fatty acid, and A fiber-reinforced plastic comprising 4 to 6 parts by weight of the curing accelerator. delete delete delete According to claim 6,
The long-chain alkyl alcohol and the fatty acid are in liquid form, fiber-reinforced plastic. According to claim 6,
The epoxy resin cured product has a glass transition temperature of 200 to 210 ℃, fiber-reinforced plastic. According to claim 6,
The fiber-reinforced plastic has an elongation of 1.8 to 2.0%, fiber-reinforced plastic. According to claim 6,
The fiber-reinforced plastic includes 60 to 70% by weight of the carbon fiber and 30 to 40% by weight of the cured epoxy resin material. According to claim 6,
The fiber-reinforced plastic has a tensile strength of 2,800 MPa or more, fiber-reinforced plastic. According to claim 6,
When the cured epoxy resin material is cured at 180 to 210 ° C. for 10 to 30 minutes, no unreacted peak according to DSC analysis occurs, fiber-reinforced plastic. According to claim 6,
The viscosity of the fast-curing epoxy resin composition is 1,500 to 3,000cps at 25 ℃, fiber-reinforced plastic. According to claim 6,
The fast-curing epoxy resin composition has a curing speed of 30 to 90 seconds under the condition of 5ml, 200 ℃, fiber-reinforced plastic. A wire core manufactured using the fiber-reinforced plastic according to any one of claims 6 and 10 to 17. A center tension wire for an overhead power transmission line comprising the wire core according to claim 18. A first step of preparing the fast-curing epoxy resin composition according to any one of claims 1, 4, and 5;
a second step of drawing continuous carbon fibers into a tank filled with the fast curing epoxy resin composition;
A third step of impregnating carbon fibers with the fast-curing epoxy resin composition;
A fourth step of drawing the carbon fiber impregnated with the fast-curing epoxy resin composition through a heated die to produce a viscous carbon fiber tow;
a fifth step of additionally drawing the viscous carbon fiber tow;
Method for producing a fiber-reinforced plastic comprising a. According to claim 20,
The fifth step of additionally drawing the viscous carbon fiber tow,
A method for producing fiber-reinforced plastic, wherein the viscous carbon fiber tow is drawn in the longitudinal direction of the die at a drawing speed of 300 mm / min toward a post-curing dryer at 200 to 220 ° C.