KR101848280B1 - Cold hardening epoxy resin using the composition and prepreg, and prepreg to make it into a layer of polymer composite - Google Patents

Abstract

The low temperature curable epoxy resin composition according to an embodiment of the present invention comprises 50 to 80% by weight of a modified solid epoxy resin; 5 to 20% by weight of a liquid bisphenol-A type epoxy resin; 0.1 to 10% by weight of modified rubber; 0.1 to 8 wt% dicyandiamide; 0.1 to 5% by weight of two methyl urea derivatives; And carbon nanotubes (CNT) in an amount of 0.1 to 3% by weight.

Description

[0001] The present invention relates to a low-temperature curing epoxy resin composition for ski making, a prepreg for ski making, and a fiber-reinforced polymer composite material using the same,

More particularly, the present invention relates to a low-temperature curing epoxy resin composition for ski making, which has a higher elastic modulus than ordinary epoxy resins and has a higher strength as it goes down to lower temperatures. In addition to preventing static electricity, Temperature curing type epoxy resin composition for excellent ski making, a prepreg for ski making manufactured thereby, and a fiber reinforced polymer composite material using the same.

A known fiber-reinforced plastic (FRP) composite material is a composite material obtained by curing fibers and a thermosetting resin. FRP composites are very resistant to corrosion and have excellent corrosion resistance. They are lighter than aluminum and have a higher specific strength than iron. They are used in almost all industrial fields such as construction, petrochemical, leisure, .

FRP composites have excellent properties such as light weight, excellent rigidity, insulation, and low thermal strain. It is also suitable for storage tanks, water leasing products, etc. It is also suitable for sealing of electrical junction terminals. EMC (epoxy molding compound) used as a sealing agent of semiconductor chip is also excellent in insulating property and low heat distortion It is possible.

Typical large structures using FRP composites include yachts and wind turbine blades. The currently manufactured yacht and wind turbine rotor blades are manufactured by a resin infusion process. After the glass fiber mat is placed in a mold, unsaturated polyester resin with low viscosity In a vacuum atmosphere.

This method is difficult to use in making high-quality yachts and wind turbine blades that require excellent physical properties and light weight, and is poor in high-value-added products because of poor quality.

In order to improve the quality and durability due to the enlargement, a method of laminating prepregs is preferable, so that the method of using the prepreg gradually increases.

However, since a typical prepreg must be cured above 125 ° C, large structures larger than the space of an autoclave can not be manufactured.

Therefore, if a low-temperature curing type prepreg is developed, heat energy can be supplied by using a hot air blower or a heating mold instead of an autoclave, so that a large structure can be manufactured.

Worldwide wind turbine manufacturers are adopting vacuum-assisted resin transfer molding (VARTM) method, and they are replacing with the prepreg method in order to increase the durability of the blades. In order to produce high-quality large-scale structures, it is required to develop low-temperature curable resins and prepregs.

Korean Patent Application Publication No. 10-2009-0052961

Disclosure of the Invention The present invention has been conceived to solve the problems of the prior art as described above, and it is an object of the present invention to provide an epoxy resin composition which is superior in elasticity to a conventional epoxy resin, A cured epoxy resin composition, a prepreg for ski making prepared therefrom, and a fiber-reinforced polymer composite material using the same.

As a means for solving the above-mentioned object, the present invention can be configured as follows.

A low-temperature curing epoxy resin composition for ski making according to an embodiment of the present invention comprises: 60 to 80% by weight of a modified solid epoxy resin; 10 to 20% by weight of a liquid bisphenol-A type epoxy resin; 2-6% by weight of modified rubber; 0.1 to 5% by weight of a dicyandiamide; 0.1 to 5% by weight of two methyl urea derivatives; And 1.3 to 3 wt% of carbon nanotubes (CNTs).

In the low temperature curable epoxy resin composition according to the present invention, the curing agent is at least one selected from anhydrides, carboxylic acids, amine compounds, phenol compounds, polyols, and mixtures thereof.

In the low temperature curable epoxy resin composition according to the present invention, the accelerator is selected from a urea compound, a phosphorus compound, an amine compound, a quaternary ammonium salt, an imidazole compound, a boron compound, a modified urea compound, a modified amine compound, Is more than one.

In the low temperature curable epoxy resin composition according to the present invention, the carbon nanotube (CNT) has a diameter of 5 to 10 nm and a length of 5 to 20 탆.

The fiber-reinforced prepreg according to the present invention is obtained by impregnating a low-temperature curable epoxy resin prepared by the above-mentioned low-temperature curable resin composition with fibers, a fabric or a mat to gel.

In the fiber-reinforced prepreg according to the present invention, the fiber is at least one fiber selected from the group consisting of carbon fiber, glass fiber, aramid fiber and boron fiber.

The fiber-reinforced polymer composite material according to the present invention is obtained by polymerizing and heating the fiber-reinforced prepreg prepared as above, and laminating and curing.

In the fiber-reinforced polymer composite according to the present invention, the laminated fiber-reinforced prepreg is cured at 50 to 120 캜. Preferably, the laminated fiber-reinforced prepreg begins to cure at < RTI ID = 0.0 > 50 C < / RTI >

According to the present invention, a fiber-reinforced prepreg obtained by impregnating and gelling a fiber with an epoxy resin prepared by a low-temperature curing epoxy resin composition which can be used as a structural material in skis production is more effective than an ordinary epoxy resin by 15% or more , The strength is 15% or more higher than other epoxy resins as it goes from low temperature to low temperature. Especially, addition of carbon nanotubes is very effective for adhesion, vibration damping and impact absorption, and is also effective for preventing static electricity.

FIGS. 1 and 2 are graphs showing changes in modulus of elasticity and strength of a low-temperature resin, that is, a fiber-reinforced prepreg according to a temperature change.
3 is a graph showing the resin flow of the composition according to the present invention.
FIGS. 4 and 5 are graphs showing mixing ratios of fiber-reinforced prepregs according to the present invention including carbon nanotubes. FIG.
6 is a graph showing FT / IR analysis results of the low-temperature resin according to the present invention.
7A and 7B are graphs showing changes in DSC and Tg as a function of temperature.

Hereinafter, the present invention will be described in detail.

The low temperature curing type epoxy resin composition for ski making according to the present invention comprises 60 to 80% by weight of a modified solid epoxy resin; 10 to 20% by weight of a liquid bisphenol-A type epoxy resin; 2-6% by weight of modified rubber; 0.1 to 5% by weight of a dicyandiamide; 0.1 to 5% by weight of two methyl urea derivatives; And 1.1-3% by weight of carbon nanotubes (CNTs).

A modified solid epoxy resin has the formula:

인 것으로서, 이는 분자량이 크고, 저온시 수축이 적어 안정적이며 수지 골격을 이루어 충격에 강하게 하며, 너무 과도 함량일 때에는 잘 부러지는(brittle) 성질을 갖게 된다.

, Which has a high molecular weight and low shrinkage at low temperature, is stable, has a resin skeleton to make it strong against impact, and has a brittle property when it is too high in content.

A liquid bisphenol-A type epoxy resin has the formula:

인 것으로서, 이는 고형 에폭시 수지와 혼용이 되어 수축을 보완해 주는 역할을 하며, 저온에서 잘 부러지는 성질을 갖게 되는 경향을 잡아준다. 20중량% 초과시에는 오히려 저온 수축 경향이 심하여 점착성 등과 같은 물성이 저하된다.

, Which is mixed with a solid epoxy resin to compensate for shrinkage and tends to have a property of breaking at low temperatures. When the amount is more than 20% by weight, the low temperature shrinkage tendency is rather severe and physical properties such as adhesiveness are lowered.

Modified rubbers have the formula:

인 것으로서, 저온 충격강도에는 열가소성 폴리머(CTBN, 페놀시 등)가 사용되는데, 이중 개질 라버가 가장 효과적이며, 10중량% 이상 초과시 경화에 영향을 주어 미경화처럼 너무 유연한 성질(flexible)을 갖게 된다.

Thermoplastic polymer (CTBN, phenol, etc.) is used as the low-temperature impact strength. The double-modified rubber is most effective and affects the curing when it is more than 10% by weight, .

인 것으로서, 무수물, 카복실산, 아민 화합물, 페놀 화합물, 폴리올, 또는 이들의 혼합물 중에서 선택되는데, 대부분 에폭시 수지엔 이 아민류 경화제를 쓰며 가용시간(pot life) 측면에서 가장 효과적이다.The dicyandiamide has the formula:

And is selected from anhydrides, carboxylic acids, amine compounds, phenol compounds, polyols, and mixtures thereof. Most epoxy resins use amine curing agents and are most effective in terms of pot life.

Two methyl urea derivatives have the formula:

인 것으로서, 우레아계 화합물, 인계 화합물, 아민계 화합물, 제4급 암모늄 염, 이미다졸류, 붕소 화합물, 변성 우레아 화합물, 변성 아민 화합물, 이미다졸 화합물 중에서 선택되는데, 이 역시 아민계 경화제와 혼용하게 되면 경화시 70∼80℃에서 경화를 촉진시키는 효과가 있으며 중온에서 수지 흐름을 환하게 하며 생산공정에서의 로스(loss)를 효과적으로 줄일 수 있다.

Is selected from a urea compound, a phosphorus compound, an amine compound, a quaternary ammonium salt, imidazoles, a boron compound, a modified urea compound, a modified amine compound and an imidazole compound. It has the effect of accelerating the curing at 70 ~ 80 ℃ when curing and brightening the resin flow at the middle temperature, and it is possible to effectively reduce the loss in the production process.

Carbon nanotubes (CNTs) are added not only to improve strength but also to improve adhesion, vibration damping and shock absorption efficiency, and preferably have a diameter of 5 to 10 nm and a length of 5 to 20 μm. This is because the fine particles and the surface area due to the needle crystals are relatively increased, thereby increasing the surface of the adhesive to increase the bonding strength and the electroconductivity is much higher, so that it is possible to easily remove the generation of static electricity at low temperature and low humidity.

A low temperature curing epoxy resin composition for ski making was prepared by mixing 65 g of solid epoxy resin, 12 g of liquid bisphenol A epoxy resin, 5 g of modified rubber, 3 g of curing agent, 2 g of accelerator and 1 g of carbon nanotubes (see Table 1 below).

A low temperature curing epoxy resin composition for ski making was prepared by mixing 65 g of solid epoxy resin, 12 g of liquid bisphenol A epoxy resin, 5 g of modified rubber, 2 g of curing agent, 3 g of accelerator and 1 g of carbon nanotubes (see Table 1 below).

- Comparative Example 1

A low temperature curing type epoxy resin composition for ski making was prepared by mixing 65 g of solid epoxy resin, 12 g of liquid bisphenol A epoxy resin, 5 g of modified rubber, 2 g of accelerator and 1 g of carbon nanotubes (see Table 1 below).

- Comparative Example 2

A low temperature curing epoxy resin composition for ski making was prepared by mixing 65 g of solid epoxy resin, 12 g of liquid bisphenol A epoxy resin, 5 g of modified rubber, 3 g of curing agent and 1 g of carbon nanotubes (see Table 1 below).

- Comparative Example 3

A low temperature curing type epoxy resin composition for ski making was prepared by mixing 65 g of solid epoxy resin, 12 g of liquid bisphenol A epoxy resin, 5 g of modified rubber, 3 g of curing agent and 2 g of accelerator (see Table 1 below).

Solid epoxy resin Liquid bisphenol A epoxy resin Reformer rubber Hardener accelerant Carbon nanotube Example 1 65 12 5 3 2 One Example 2 65 12 5 2 3 One Comparative Example 1 65 12 5 0 2 One Comparative Example 2 65 12 5 3 0 One Comparative Example 3 65 12 5 3 2 0

The compositions of Examples 1 and 2 and Comparative Examples 1 to 3 were heated to produce a low-temperature resin and impregnated with the fibers to prepare a fiber-reinforced prepreg for ski making. A composite material was made using this. At this time, the low-temperature resin was cured at 70 to 80 ° C and cured at 120 ° C.

Particularly, it was confirmed through the adhesion strength test that the addition of the carbon nanotubes increased the adhesive strength between the prepreg layers, and the generation of bubbles was reduced, thereby increasing the bonding strength.

UD prepregs are prepared uniformly on the UD machine, that is, the fibers are impregnated with the low-temperature resin to prepare the fiber-reinforced prepregs, and the above epoxy resin, liquid bisphenol A resin, modified rubber, hardener, accelerator, The results are shown in Table 1. The results are shown in Table 1 below.

At this time, the impregnation temperature is impregnated at 70 to 80 ° C, and when the prepreg is cured, it is completely cured at 120 to 130 ° C for 30 to 40 minutes.

As shown in FIGS. 1 and 2, the low temperature occasional composition for ski making according to the present invention can be applied not only to sporting goods including skis but also to various structural materials, and has a modulus of elasticity of 15% It is more effective than epoxy resin and the property is consistently more than 15% higher than general epoxy resin as the temperature is lowered. Particularly, the addition of carbon nanotubes not only excelles in adhesion, vibration damping and shock absorption, but also is effective in preventing static electricity.

The Tg (glass transition temperature) of the fiber-reinforced prepreg for ski fabrication according to the present invention is similar to that of ordinary epoxy resin at 150 ° C or less, and the prepreg, which is a radial cargo impregnated in the fiber-reinforced prepreg, for,

Upon heating

- resin flow,

- Flexibility of prepreg

- tackmess of the prepreg

- The pot life must meet the conditions for production at the same time.

The fact that the hot flow of the resin starts to harden in a relatively wide distribution is a prepreg suitable for use in the field.

The resin flow of this resin is shown in Fig.

In other words, as shown in Fig. 3, when the fiber-reinforced polymer composite material is formed by laminating the fiber-reinforced polymer composite material for ski making, the viscosity is lowered from about 50 deg. C (mold preheating temperature), and then rapidly hardened at about 80 deg. Respectively. These prepregs are slowly cured from 50 ° C, that is, they have a wide temperature range, indicating that they can be well cured unless the temperature control is largely mistaken in actual situations.

The solid epoxy resin was melted in a molten liquid and completely dissolved with the liquid bisphenol epoxy resin at 50 ° C or less. The modified rubber, the curing agent, the accelerator and the carbon nanotubes were mixed again in the third roll of the epoxy resin mixture UD, which is a unidirectional fabric, was put into machine resin.

Since the low temperature resin composition according to the present invention manufactured as described above is dependent on the viscosity and flexibility depending on the amounts of the curing agent, the promoter and the carbon nanotube, by optimizing the ratio thereof, it is possible to have flexibility with tackiness , And when a plurality of, especially 50 or more, sheets are stacked and cured to form a fiber-reinforced polymer composite material, not only the respective prepregs are well adhered but also voids are prevented from entering between the prepregs.

In particular, the fiber-reinforced prepreg for ski fabrication can increase the physical properties of the fiber-reinforced prepreg because the carbon nanotubes are added at the blending ratios shown in FIGS. 4 and 5, and the adhesive strength and the tackness are high.

6 is a graph showing FT / IR analysis results of the fiber-reinforced prepreg according to the present invention.

As shown in FIGS. 7A and 7B, the prepreg made of the low-temperature resin composition for ski making according to the present invention has a high adhesive strength, tensile strength and elastic modulus of 20 to 30% or more of the general epoxy resin. That is, the tensile strength is 155 MPa at 25 to 30 ° C, the flexural strength is 160 MPa, and the elongation is within 30%.

The pot life of the prepreg is 5 days at 25 ° C, 30 days at 0 ° C, and 1 year at -25 ° C.

The Tg graph of the low-temperature resin composition according to one embodiment of the present invention shows that it is around 150 캜 as shown in Figs. 7A and 7B.

Hereinabove, a low temperature curing epoxy resin composition for ski making according to the present invention, a prepreg for ski making prepared therefrom, and a fiber reinforced polymer composite material using the same are described with reference to the accompanying drawings. These embodiments are included in the technical idea described in the claims of the present invention. Furthermore, these embodiments are merely illustrative and should not be construed as limiting in interpreting the claims of the present invention.

Claims (9)

60 to 80% by weight of a modified solid epoxy resin;
10 to 20% by weight of a liquid bisphenol-A type epoxy resin;
2-6% by weight of modified rubber;
0.1 to 5% by weight of at least one dicyandiamide selected from anhydrides, carboxylic acids, amine compounds, phenol compounds, polyols, or mixtures thereof;
Urea compound, two-methyl urea derivatives of at least one selected from solid, phosphorous, amine, quaternary ammonium, imidazole, boron, modified urea, modified amine and imidazole compounds, 5% by weight; And
(CNT) having a diameter of 5 to 10 nm and a length of 5 to 20 占 퐉 at a ratio of 1.3 to 3% by weight. delete delete delete A modified solid epoxy resin 60 to 80% by weight, a liquid bisphenol-A type epoxy resin 10 to 20% by weight, a modified rubber 2 to 6% by weight, an anhydride, a carboxylic acid 0.1 to 5% by weight of at least one dicyandiamide selected from the group consisting of an amine compound, a phenol compound, a polyol, and mixtures thereof, a urea compound, a phosphorus compound, an amine compound, a quaternary ammonium salt, an imidazole, 0.1 to 5% by weight of two methyl urea derivatives selected from the group consisting of a compound, a modified urea compound, a modified amine compound and an imidazole compound, and carbon nanotubes having a diameter of 5 to 10 nm and a length of 5 to 20 탆 (CNT ) 1.3 to 3% by weight of a low-temperature curing epoxy resin for ski making prepared by a low-temperature curing epoxy resin composition for ski making is mixed with carbon fiber, glass fiber, aramid fiber and boron fiber Luer binary by impregnating the fiber or fabric or mat least one member selected from the group gel was ski for producing a fiber-reinforced prepreg. delete A modified solid epoxy resin 60 to 80% by weight, a liquid bisphenol-A type epoxy resin 10 to 20% by weight, a modified rubber 2 to 6% by weight, an anhydride, a carboxylic acid 0.1 to 5% by weight of at least one dicyandiamide selected from the group consisting of an amine compound, a phenol compound, a polyol, and mixtures thereof, a urea compound, a phosphorus compound, an amine compound, a quaternary ammonium salt, an imidazole, 0.1 to 5% by weight of two methyl urea derivatives selected from the group consisting of a compound, a modified urea compound, a modified amine compound and an imidazole compound, and carbon nanotubes having a diameter of 5 to 10 nm and a length of 5 to 20 탆 (CNT ) 1.3 to 3% by weight of a low-temperature curing epoxy resin for ski making prepared by a low-temperature curing epoxy resin composition for ski making is mixed with carbon fiber, glass fiber, aramid fiber and boron fiber Luer binary curing a fiber-reinforced under the temperature condition of the ski 1, for manufacturing a fiber-reinforced were gel was impregnated with a species or more fibers or fabric or mat is selected from the group sikidoe laminated by heating the prepreg polymerizing 50~120 ℃ polymer composites. delete 8. The fiber-reinforced polymeric composite material according to claim 7, wherein the laminated fiber-reinforced prepreg for ski fabrication is cured at 50 to < RTI ID = 0.0 >

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