KR101880002B1 - High speed curing resin composition and composite material intermediate comprising the same - Google Patents

Abstract

The present invention can provide a fast-curing resin composition having good wettability to a reinforcing substrate due to its good resin flow, which is advantageous for the production of a composite material intermediate, and the composite material intermediate containing the composite intermediate material has a tack- Excellent productivity due to shortening of molding time because of short curing time.

Description

TECHNICAL FIELD [0001] The present invention relates to a high-speed cured resin composition and a composite intermediate containing the same. BACKGROUND OF THE INVENTION [0002]

The present invention is advantageous in that it has good wettability to a reinforcing base material due to its good resin flow and therefore has advantages of workability and advantageous workability when it is advantageous in the production of a composite material intermediate and has a short curing time, And a composite intermediate containing the same.

Generally, carbon fiber reinforced composite materials have high rigidity and light weight properties. Because of these properties, carbon fiber reinforced composite materials are being used in various fields such as aircraft structural materials, automotive structural materials, sporting goods, and protective helmets. However, the carbon fiber reinforced composite material has various molding methods, and properties and molding time are determined according to the properties of the resin used. Since the molding method and the molding time are directly related to the productivity, much research has been carried out so far to shorten the molding method and the molding time.

As a conventional method of manufacturing the helmet body, a reinforced fiber mat or fabric, which has left and right molds according to the shape of the helmet body, is laminated by a required number in a mold, and resin is injected into the high- And the mold was separated from the mold, thereby forming the helmet main body by removing the molded helmet body.

However, when the conventional helmet body is formed by molding with FRP, the helmet body has a structure that is woven by reinforcing fiber mat or fiber structure, the surface of the helmet body is not smooth, , The strength and the impact resistance are excellent. On the other hand, there is a problem that the surface becomes rough and the weight becomes large. Also, the reinforcing fiber woven fabric is cut to an appropriate size, and the shape of the woven fabric is deformed during handling, resulting in poor weaving.

As a method to solve this problem, there is a method using a double structure in which an outer shell is manufactured separately from a plastic having a good surface condition and joined to an FRP shell (Korean Utility Model Registration No. 20-0171973, Korean Patent Laid- -0038599) and a manufacturing method for removing resin pinholes by minimizing the resin content by providing a vacuum device in molding the FRP shell (Korean Patent Laid-Open Publication No. 2000-0014383). However, in such a manufacturing method, the number of workpieces for fabricating a double structure shell increases, and in the case of a vacuum molding apparatus, it is difficult to impregnate the resin and adjust the total resin content, and it is difficult to provide separate facilities.

As a result of applying the composite intermediate (prepreg) which consists of the reinforcing fiber and the used resin to solve the above problem, it is possible to improve the working environment and to manage the body of the helmet with a desired weight, and the surface of the body of the helmet after molding is smooth And a method capable of improving workability and improving mechanical properties has been devised (Korean Patent No. 10-0701746).

However, this method does not take into account the workability of the resin to be used, and a product satisfying desired physical properties can not be obtained unless curing is carried out for 30 minutes under a high-temperature and high-pressure environment.

Therefore, in order to solve the above problems, a method for a resin having a short molding time, excellent impregnation property, and good flow property has been proposed (Korean Patent Registration No. 10-1351330). However, in this method, the molding time is shortened to 10 minutes or less to improve the productivity of the product. However, in the step of preparing the resin, a step of complicating the pre-processing by mixing with a complicated composition and stabilizing the resin by aging for 20 to 30 hours There is a problem that the overall productivity is lowered.

Korea Utility Model Registration No. 20-0171973 Korean Patent Publication No. 10-2001-0038599 Korean Patent Publication No. 2000-0014383 Korea Patent No. 10-0701746 Korea Patent No. 10-1351330

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-mentioned problems, and an object of the present invention is to provide a resin composition which is excellent in flowability of a resin to improve resin impregnation property to a reinforcing substrate, And a short curing time is possible to improve productivity, and a composite material intermediate containing the same.

These and other objects and advantages of the present invention will become more apparent from the following description of a preferred embodiment thereof.

This object is achieved by a fast curing resin composition for producing a composite intermediate, which comprises 5 to 15 parts by weight of a curing agent and 5 to 50 parts by weight of a solvent based on 100 parts by weight of an epoxy resin.

Here, the epoxy resin is a bisphenol A type epoxy resin, and the epoxy equivalent weight may be 150 g / eq to 990 g / eq.

Preferably, the curing agent may be dicyanamide.

Preferably, the mixing ratio of the epoxy resin to the curing agent may be 0.5 to 1.5 as the number of functional groups.

Preferably, the viscosity of the fast curing resin composition may be 100 to 5000 cps.

Further, the above object is achieved by a composite intermediate characterized in that the reinforcing base material is dipped in the above-described fast curing resin composition and then dried to produce a B-stage state.

Here, the reinforcing substrate may be at least one of carbon fiber, glass fiber, aramid fiber, metal fiber, boron fiber, alumina fiber, and silicon carbide high strength synthetic fiber.

Preferably, the Tack of the composite intermediate may be 10 to 300 gf / mm ² .

Preferably, the composite intermediate is characterized in that when it is made into a product, the curing is completed within 0.1 to 6 minutes at 140 to 180 ° C.

INDUSTRIAL APPLICABILITY According to the present invention, the flowability of the resin is improved, so that the impregnation property of the resin in the molding step is improved, and the deterioration of the physical properties due to the impregnation of the resin through the resin can be prevented.

In addition, it is possible to realize a tack property optimized for the operation of the composite material intermediate, and it is possible to rework the composite material without loss of the intermediate material even when the work is easy and reworking is required, thereby reducing workability and process cost .

In addition, since the curing time of the resin is short, the productivity can be improved and the production cost can be reduced.

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

Hereinafter, the present invention will be described in detail with reference to examples of the present invention. It will be apparent to those skilled in the art that these embodiments are provided by way of illustration only for the purpose of more particularly illustrating the present invention and that the scope of the present invention is not limited by these embodiments .

Unless otherwise defined, 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 can be used in the practice or testing of the present invention, suitable methods and materials are described herein.

The fast curing resin composition according to one aspect of the present invention comprises 5 to 15 parts by weight of a curing agent and 5 to 50 parts by weight of a solvent based on 100 parts by weight of the epoxy resin. This will be described in detail below.

[Fast curing resin composition]

In the present invention, a thermosetting resin such as a polyester resin or a thermosetting resin such as an epoxy resin and a phenol resin can be used as the fast curing resin, but a thermosetting resin, particularly an epoxy resin, can be used in terms of excellent mechanical properties and heat resistance .

As the epoxy resin, a compound having a plurality of epoxy groups in the molecule is used, and in particular, amines, phenols, and compounds having carbon-carbon double bonds are preferably used. Examples of such resins include bisphenol type epoxy resins such as bisphenol A type epoxy resin, bisphenol F type epoxy resin and bisphenol S type epoxy resin, and novolak type epoxy resins such as phenol novolak type epoxy resin and cresol novolak type epoxy resin , Which may be used alone or in combination. Particularly, it is preferable to use a bisphenol A type epoxy resin. The epoxy equivalent of the epoxy resin is preferably from 150 g / eq to 990 g / eq. When the epoxy equivalent is less than 150 g / eq, the resin hardenability of the resin cured product is insufficient and the toughness is insufficient. eq, there is a disadvantage in that heat resistance of the resin cured product is insufficient, and at the same time, viscosity is increased and handling is difficult.

As the epoxy resin composition, a curing agent is used. As the curing agent, any curing agent may be used as long as it is a compound having an active group capable of reacting with an epoxy group. Preferably, a compound having an amino group, an acid anhydride group and an azide group is used. In particular, it is more preferable to use dicyanamide.

In the fast curing resin composition according to an embodiment of the present invention, the compounding ratio of the epoxy resin and the curing agent is preferably 0.5 to 1.5 in terms of the number of functional groups. When the compounding ratio is less than 0.5, And if it exceeds 1.5, the viscosity of the resin composition becomes high and it is difficult to handle.

The solvent which can be used in the preparation of the resin composition using the epoxy resin and the curing agent is a solvent having a high polarity such as dimethylformamide (DMF), ethylene glycol, dimethylsulfoxide (DMSO), dimethylacetamide DMAc), and methyl ethyl ketone (MEK) may be used alone or in admixture of two or more. In particular, methyl ethyl ketone (MEK) is preferably used.

The composite intermediate according to another aspect of the present invention is prepared by dipping a reinforcing base material into the above-mentioned quick-curing resin composition and then drying it to obtain a B-stage state. This will be described in detail below.

[Composite material intermediate]

The reinforcing base material is preferably at least one reinforcing base material selected from the group consisting of carbon fiber, glass fiber, aramid fiber, metal fiber, boron fiber, alumina fiber and silicon carbide high strength synthetic fiber. In particular, carbon fibers, glass fibers and aramid fibers are more preferable.

The carbon fiber tow or the carbon fiber fabric may be any carbon fiber tow or carbon fiber fabric that can be used in the field, and the tow or fabric may be appropriately selected depending on the use thereof.

Preferably, the carbon fiber tow has a specific gravity of 1.7 to 1.9. When the specific gravity is lower than 1.7, voids or the like are often present in the carbon fiber filaments forming the carbon fiber tow, or the compactness of the carbon fiber filaments is lowered. Accordingly, the carbon fiber tow comprising a plurality of such carbon fiber filaments is used The carbon fiber-reinforced composite material to be formed has a low compressive strength. When the specific gravity is higher than 1.9, the effect of reducing the weight of the carbon fiber-reinforced composite material is lowered. For this reason, it is more preferable that the specific gravity is 1.75 to 1.85.

It is also preferable that the number of filaments per tow of carbon fiber tow is 1,000 to 400,000. When the number of filaments is less than 1,000, the area ratio per unit area of the carbon fiber-reinforced composite material is decreased during manufacture of the large-area carbon fiber-reinforced composite material, which increases the manufacturing cost and increases the cost of the product. The tensile strength and the compressive strength of the carbon fiber-reinforced composite material produced are lowered.

As a method for producing a composite material intermediate using the above-described components, a reinforcing base material is dipped in the above-described fast curing resin composition prepared by mixing a resin, a curing agent, and a solvent, followed by drying. Also, the quick-curing resin composition is prepared by dipping the reinforcing base material at a viscosity of 100 to 5000 cps which is excellent in impregnation property and easy to work. When the viscosity is less than 100 cps, the content of the resin composition remaining on the reinforcing base material is lowered, and the content of the resin is insufficient during the production of the composite material, which may cause surface damage. If the viscosity exceeds 5000 cps, the reinforcing base material is not sufficiently impregnated and the strength is lowered due to the non-impregnated portion inside.

The prepared quick-curing resin composition is impregnated with a reinforcing base material to carry out pre-cure to prepare a composite material intermediate on the B-stage, and a surface protective layer is laminated on both sides to form a composite material intermediate.

Here, the B-stage state is a state in which the resin is semi-cured and is completely cured at the time of manufacturing the finished product using the composite material intermediate. When the prepared composite intermediate is in the A-stage state (uncured state), the impregnated resin can not maintain its shape and the subsequent work becomes impossible. In the case of the C-stage state (fully cured state) Thus, a problem that a desired product shape can not be changed occurs. The composite intermediate according to one embodiment of the present invention is characterized in that the curing is completed within 0.1 to 6 minutes at 140 to 180 ° C when the composite intermediate is manufactured into a product.

The composite intermediate according to one embodiment of the present invention preferably has a Tack property of 10 to 300 gf / mm ² . When the tack property is less than 10 gf / mm ² , there is a problem that the adhesion between the layers becomes weak, and the shape is deformed at the time of work or the bonded portion is detached and the productivity is lowered. When the tack property is more than 300 gf / mm ^2, It is difficult to rework at the time of work, and therefore, when the work is repeated, the manufacturing cost is increased due to the problem that the used material must be discarded.

Hereinafter, the structure and effect of the present invention will be described in more detail with reference to examples and comparative examples. However, this embodiment is intended to explain the present invention more specifically, and the scope of the present invention is not limited to these embodiments.

[Example 1]

10 parts by weight of methyl ethyl ketone (MEK) solvent was added to 100 parts by weight of bisphenol A-epichlorohydrin epoxy resin (KER828, Kumho P & Co.) and 15 parts by weight of dicyanamide hardener (DICY7, Japan Epoxy Resin Co., Ltd.) A fast curing resin composition was prepared. After dipping a carbon fiber cloth (JM1321P, JMC) into the prepared quick-setting resin composition, it was pre-cured at 130 ° C for 3 minutes and then a 50 μm release film (WL5200B, AIRTECH) .

[Example 2]

A composite material intermediate was prepared in the same manner as in Example 1, except that 7 parts by weight of the dicyandiamide curing agent was used.

[Example 3]

In Example 1, 30 parts by weight of methyl ethyl ketone (MEK) solvent was used to prepare a composite material intermediate in the same manner.

[Comparative Example 1]

In Example 1, 1 part by weight of a dicyanamide curing agent was used to prepare a composite material intermediate in the same manner.

[Comparative Example 2]

A composite material intermediate was prepared in the same manner as in Example 1, except that 50 parts by weight of the dicyanamide curing agent was used.

[Comparative Example 3]

1 part by weight of a methyl ethyl ketone (MEK) solvent was used in Example 1 to prepare a composite material intermediate in the same manner.

[Comparative Example 4]

In Example 1, 70 parts by weight of a methyl ethyl ketone (MEK) solvent was used to prepare a composite material intermediate in the same manner.

[Comparative Example 5]

40SHCU100NS product of Korea Carbon Co., Ltd. was used for comparison with commercial composite intermediates.

[ Comparative Example  6]

For comparison with commercial composite intermediates, SK Chemicals USN100C was used.

The resin compositions and composite materials according to Examples 1 to 3 and Comparative Examples 1 to 6 were used to measure physical properties through the following experimental examples, and the results are shown in Table 1 below.

[Experimental Example]

[Experimental Example 1: Measurement of viscosity]

The resin compositions prepared in Examples and Comparative Examples were mounted on Spindle S63 in a viscometer (model: DV-I) manufactured by BROOKFIELD, and the viscosity was measured at a speed of 12 RPM.

[Experimental Example 2: Measurement of Tack Property]

The composite intermediate prepared in Examples and Comparative Examples was cut into 5 cm × 5 cm and fixed with a double-sided tape on an SUS plate. Then, a spherical probe was attached to a TA texure tack measuring machine, mm / s and the maximum value was measured to determine the Tack property.

[Experimental Example 3: Resin impregnability test]

Sections cut out on the surface and scissors of the composite intermediate prepared in Examples and Comparative Examples were confirmed by a microscope. A site impregnated on the observation surface of 500 mu m or more was defined as the non-impregnated site.

○: Less than 5 non-impregnated parts on the surface.

[Delta]: Less than 10 non-impregnated portions on the surface at 5 or more points.

Χ: More than 10 non-impregnated parts on the surface.

[Experimental Example 4: Re-workability test]

When two composite intermediate materials prepared in Examples and Comparative Examples were stacked and arranged, the number of times that uniform rework was possible was measured.

○: 3 times or more

?: 1 to 2 times

Χ: No rework

[Experimental Example 5: Measurement of curing time]

The composite intermediate prepared in Examples and Comparative Examples was cut into 5 cm x 5 cm and cured in an oven set at 140 ° C to measure the disappearance of uncured portions on the surface and inside.

○: Curing time: 6 minutes or less

△: Hardening time More than 6 minutes and less than 30 minutes

Χ: Curing time 30 minutes or more

Viscosity Tack Castle Resin impregnation property Reworkability Curing time Example 1 478 cps 169 gf / mm < ^{2 >} ○ ○ ○ Example 2 441 cps 247 gf / mm < ^{2 >} ○ ○ ○ Example 3 137 cps 143 gf / mm ² ○ ○ ○ Comparative Example 1 521 cps 985 gf / mm < ^{2 >} ○ Χ Χ Comparative Example 2 387 cps 1 gf / mm < ^{2 >} ○ No lamination ○ Comparative Example 3 1023 cps 201 gf / mm ² Χ ○ ○ Comparative Example 4 57 cps 47 gf / mm ² ○ ○ ○ Comparative Example 5 - 131 gf / mm ² - ○ Χ Comparative Example 6 - 252 gf / mm < ^{2 >} - ○ Χ

As can be seen from the above Table 1, when the composite material intermediate is prepared by using the fast curing resin composition according to the embodiment of the present invention, excellent resin impregnation and reworkability can be ensured, It is confirmed that the curing speed is increased and the productivity is improved.

On the other hand, when the content of the curing agent is small as in Comparative Example 1, the degree of curing during the pre-curing process is low and it is difficult to rework due to the high tack property and the curing time is also prolonged. Also, as in Comparative Example 2, when the content of the curing agent is large, most of the curing proceeds at the time of pre-cure, and it is confirmed that molding of the composite material is difficult. In addition, as in Comparative Examples 3 and 4, if the content of the solvent is small, the viscosity becomes high and the resin impregnability is low to cause the non-impregnated portion to have a problem of deteriorating the physical properties of the product, The content of the resin is lowered in the interior of the composite material, resulting in difficulty in molding the product. In addition, as in Comparative Examples 5 and 6, it can be confirmed that the composite intermediate provided by the present invention has a shorter curing time than the existing products and is advantageous for improving the productivity.

It is to be understood that the present invention is not limited to the above embodiments and various changes and modifications may be made by those skilled in the art without departing from the spirit and scope of the invention.

Claims (7)

A fast curing resin composition comprising a bisphenol A type epoxy resin having an epoxy equivalent of 150 g / eq to 990 g / eq, a curing agent and a solvent, and
A composite intermediate comprising a carbon fiber tow dipped in the fast curing resin composition,
Wherein the carbon fiber tow has a specific gravity of 1.7 to 1.9, a number of filaments per tow of 1,000 to 400,000,
Wherein the fast curing resin composition comprises 7 to 15 parts by weight of the curing agent and 10 to 30 parts by weight of the solvent based on 100 parts by weight of the bisphenol A type epoxy resin,
The viscosity of the fast curing resin composition is from 137 to 478 cps,
Wherein the composite intermediate has a Tack of 143 to 247 gf / mm ² . delete The method according to claim 1,
Wherein the curing agent is dicyanamide. delete delete The method according to claim 1,
Wherein a mixing ratio of the epoxy resin to the curing agent is 0.5 to 1.5 as the number of functional groups. The method according to any one of claims 1, 3, and 6,
Wherein said composite intermediate is made into a product and curing is completed within 0.1 to 6 minutes at 140 to 180 占 폚.