KR101470803B1 - Thermoplastic carbon fiber reinforced composite and manufacturing method thereof - Google Patents

Abstract

The present invention relates to a thermoplastic carbon fiber reinforced composite material and to a manufacturing method thereof, and more specifically, to a uniform thermoplastic carbon fiber reinforced composite material having no air pocket and regular thickness, and to a novel manufacturing method which can mass-produce the same. According to the present invention, the uniform thermoplastic carbon fiber reinforced composite material having no air pocket and regular thickness can be mass-produced that impregnation property of a resin in carbon fiber is increased without operating a complex process such as surface treatment of carbon fiber. Accordingly, a molded object using the same can be produced in a short period of time.

Description

Technical Field [0001] The present invention relates to a thermoplastic carbon fiber reinforced composite material,

More particularly, the present invention relates to a homogeneous thermoplastic carbon fiber-reinforced composite material having no air pocket and a uniform thickness, and a novel manufacturing method for mass-producing the same. will be.

Recently, materials with new characteristics are required from aerospace to a wide range of industries, and active research is underway. Among them, carbon fiber is a high strength and high elastic material, and it is widely used as a reinforcing material of high-tech composite materials because of its light weight and high workability. A representative example of such a high-tech composite material is a carbon fiber-reinforced resin in which a carbon fiber is mixed with a polymer resin to increase the strength. This composite material combines the merits of carbon fiber with excellent moldability and high strength of polymer resin, and it is classified into thermoplastic and thermosetting depending on the kind of resin which becomes the matrix.

Conventionally, a thermosetting resin such as an epoxy, an unsaturated polyester, a vinyl ester, a phenol resin, or a polyimide is mainly used to impregnate a mat of a carbon fiber with a resin having a low molecular weight having excellent fluidity and to perform autoclave or resin transfer molding a thermosetting carbon fiber reinforced composite material is produced by forming a crosslink in the resin when heated and pressed by a resin transfer molding (RTM) molding method, but it takes a long time to obtain a desired molded article through such a process Patent Document 1).

In addition, when the thermosetting carbon fiber-reinforced composite material is prepared by a vacuum bag molding (VBM) method other than the above-mentioned method, in order to prevent deterioration of the physical properties of the composite material due to the viscosity decrease of the thermosetting resin solution, There is a problem in that the manufacturing process of the thermosetting carbon fiber reinforced composite material is complicated as a whole by adding another process to the existing manufacturing process including the energy consumption due to the heat treatment (Patent Document 2).

Therefore, a thermoplastic resin such as nylon, polycarbonate, polybutylene terephthalate or the like is used as a matrix in place of the thermosetting resin to heat the mat on a carbon fiber to impregnate the molten resin, followed by cooling or dispersing the short fibers in the resin There have been many attempts to produce a thermoplastic carbon fiber reinforced composite material by a simple method such as injection molding in the form of pellets.

In recent years, there has been known a method for producing a thermoplastic carbon fiber-reinforced composite material including a step of applying a carbon fiber and a thermoplastic resin on a sheet when the matrix resin is thermoplastic, and then fixing the applied carbon fiber and the thermoplastic resin , This process uses a thermoplastic resin in the form of a fiber or a powder and uses an air suction method. Therefore, there is a space such as an air pocket in the carbon fiber-reinforced composite material, which causes deterioration of mechanical properties, a homogeneous carbon fiber-reinforced composite material can not be produced (Patent Document 3).

In manufacturing the carbon fiber-reinforced composite material, the surface of the carbon fiber is subjected to plasma treatment or corona discharge treatment in order to increase the impregnation property of the resin to the carbon fiber (increase the bonding strength between the carbon fiber and the resin) The processing speed is slow and the processing time is long, a large apparatus is required, and the process is complicated, and ultimately, a satisfactory effect can not be obtained (Patent Document 4).

Therefore, the present inventors have found that when a thermoplastic resin is made into a film and heated and pressed together with the carbon fiber, the thermoplastic resin is melted and the thermoplastic resin melted at a certain pressure is impregnated into the carbon fiber, It is possible to mass-produce a uniform thermoplastic carbon fiber-reinforced composite material having a uniform thickness without air pockets and ultimately to produce a desired molded body in a short time, Has reached the invention.

Patent Document 1: JP-A-2009-114611 Patent Document 2: Korean Patent Publication No. 2010-0108858 Patent Document 3: JP-A-2013-49749 Patent Document 4 European Patent Publication No. 0590656

SUMMARY OF THE INVENTION It is a first object of the present invention to provide a uniform thermoplastic carbon fiber-reinforced composite material of uniform thickness without air pockets, and a second object of the present invention is to provide a carbon fiber- Provided is a manufacturing method capable of mass-producing a uniform thermoplastic carbon fiber-reinforced composite material and a molded body having a constant thickness without air pockets in a short period of time, without impairing the air pocket, without impairing the complicated processes such as surface treatment. I would like to.

A) a thermoplastic resin matrix on the film; and b) a carbon fiber cloth having a thickness of 3K to 48K or a carbon fiber cloth having a length of 6 to 12 mm, wherein the thermoplastic resin is carbon And 10 to 100 parts by weight based on 100 parts by weight of the fibers.

Wherein the thermoplastic resin is selected from the group consisting of thermoplastic polyurethane, polyurethane, polyamide, polyethylene, polypropylene, polystyrene, polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, polyvinyl acetate, acrylonitrile- Butadiene-styrene copolymer, acrylic resin, methacrylic resin, polyacetal, polycarbonate, polyarylate, polysulfone, polyethersulfone, polyetheretherketone, polylactide, polyphenylene sulfide, polyethylene terephthalate, polybutyl Is selected from the group consisting of polyethylene terephthalate, polyethylene terephthalate, polyethylene naphthalate, and polybutylene naphthalate.

And a plastic molded body using the thermoplastic carbon fiber-reinforced composite material.

The present invention also provides a method for producing a double-belt press, comprising the steps of: i) feeding a thermoplastic resin sheet and a carbon fiber together into a double belt press; ii) transferring the thermoplastic resin through the circulating roller after melting the thermoplastic resin in the fixing roller; iii) pressing the melted thermoplastic resin under an isostatic pressure to impregnate the carbon fiber with the film-like thermoplastic resin; And iv) solidifying the mixture on a chill roller. The present invention also provides a method for producing a thermoplastic carbon fiber-reinforced composite material.

In the step ii), the thermoplastic resin is melted at a temperature higher than the melting point of the thermoplastic resin or at a temperature higher than the glass transition temperature.

The steps i) to iv) are performed at a speed of 0.2 to 0.5 m / min by a double belt press.

The present invention also provides a method for producing a plastic molded article by hot stamping a thermoplastic carbon fiber-reinforced composite material produced according to the present invention.

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to mass-produce a uniform thermoplastic carbon fiber-reinforced composite material having a constant thickness without air pockets, without impairing the complex process such as carbon fiber surface treatment, The formed body can be manufactured within a short time.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a roll-shaped thermoplastic carbon fiber-reinforced composite material produced according to the present invention. Fig.
Fig. 2 is a thermoplastic carbon fiber-reinforced composite material cut according to a mold for forming a molded article.
Fig. 3 is a molded article obtained by hot stamping using the thermoplastic carbon fiber-reinforced composite material produced according to the present invention.
4 is an actual process for producing a thermoplastic carbon fiber reinforced composite material using a double belt press according to the present invention.
5 is a view illustrating a manufacturing process of a thermoplastic carbon fiber reinforced composite material using a double belt press according to an embodiment of the present invention.
6 is a process diagram for hot stamping and molding a thermoplastic carbon fiber-reinforced composite material produced according to an embodiment of the present invention.

Hereinafter, a uniform thermoplastic carbon fiber-reinforced composite material having no air pockets and a uniform thickness according to the present invention and a novel production method for mass production thereof will be described in detail with reference to the drawings.

The present invention relates to a thermoplastic resin composition comprising a) a thermoplastic resin matrix on a film, and b) a carbon fiber cloth having a thickness of 3 to 48 K or a carbon fiber cloth having a length of 6 to 12 mm, By weight of a thermoplastic carbon fiber-reinforced composite material.

As the thermoplastic resin matrix constituting the thermoplastic carbon fiber-reinforced composite material of the present invention, a film formed by an isobaric press described later is used. In the past, a thermoplastic resin in liquid, fiber or powder form was used , Since the air suction method is applied in the process of impregnating the carbon fiber with the thermoplastic resin, voids such as air pockets are present in the carbon fiber reinforced composite material, which may cause deterioration of mechanical properties, there is a problem that a homogeneous carbon fiber reinforced composite material can not be manufactured. Therefore, in the present invention, the impregnability of the thermoplastic resin to the carbon fiber can be basically improved by using the thermoplastic resin matrix on the film.

The material of the film-like thermoplastic resin matrix is not particularly limited as long as it is generally known as a thermoplastic resin. Specific examples thereof include thermoplastic polyurethane, polyurethane, polyamide, polyethylene, polypropylene, polystyrene, polyvinyl chloride, polyvinylidene chloride , Polyvinyl alcohol, polyvinyl acetate, acrylonitrile-styrene copolymer, acrylonitrile-butadiene-styrene copolymer, acrylic resin, methacrylic resin, polyacetal, polycarbonate, polyarylate, polysulfone, polyethersulfone , Polyether ether ketone, polylactide, polyphenylene sulfide, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, and polybutylene naphthalate. Particularly, thermoplastic polyurethane ( thermoplastic polyurethane, TPU) can be more preferably used.

On the other hand, the carbon fiber composing the thermoplastic carbon fiber-reinforced composite material of the present invention is not limited to a fabric type or a chop type, but in the case of a fabric type, the thickness of the carbon fiber Is 3K to 48K, and in the case of the 촙 shape, it is preferable to use a long fiber having a length of 6 to 12 mm because a homogeneous thermoplastic carbon fiber reinforced composite material can be obtained.

Since the thermoplastic resin contains 10 to 100 parts by weight of the carbon fiber per 100 parts by weight of the carbon fiber, it contributes to high strength and high elasticity to maximize the mechanical properties. Therefore, the blending amount of the thermoplastic resin and the carbon fiber is controlled within the above range.

FIG. 1 is a photograph of a roll-shaped thermoplastic carbon fiber-reinforced composite material produced according to the present invention, showing that a large-area thermoplastic carbon fiber-reinforced composite material can be stably mass-produced.

Further, as shown in Fig. 2, a rolled thermoplastic carbon fiber-reinforced composite material is cut in accordance with a metal mold and then molded by a known vacuum molding method, a hydraulic pressure molding method, a hot stamping molding method, In the present invention, as shown in FIG. 3, the plastic molded body manufactured by hot stamping molding is more preferable in terms of high-speed molding.

According to the present invention, there is provided a method for mass production of a uniform thermoplastic carbon fiber-reinforced composite material having no air pocket and a uniform thickness, comprising the steps of: i) feeding a thermoplastic resin sheet and carbon fiber together into a double belt press; ii) transferring the thermoplastic resin through the circulating roller after melting the thermoplastic resin in the fixing roller; iii) pressing the melted thermoplastic resin under an isostatic pressure to impregnate the carbon fiber with the film-like thermoplastic resin; And iv) solidifying the mixture on a chill roller. The present invention also provides a method for producing a thermoplastic carbon fiber-reinforced composite material.

The thermoplastic resin sheet in step i) may be any sheet-like thermoplastic resin, but may be any of thermoplastic polyurethane, polyurethane, polyamide, polyethylene, polypropylene, polystyrene, polyvinyl chloride, polyvinylidene chloride, Butadiene-styrene copolymer, an acrylic resin, a methacrylic resin, a polyacetal, a polycarbonate, a polyarylate, a polysulfone, a polyether sulfone, a polyether ether ketone, an acrylonitrile- , A polylactide, a polyphenylene sulfide, a polyethylene terephthalate, a polybutylene terephthalate, a polyethylene naphthalate, and a polybutylene naphthalate.

On the other hand, the carbon fiber is not limited to a fabric type or a chop type. However, in the case of a fabric type, the thickness of the carbon fiber is 3K to 48K, It is preferable to use long fibers having a carbon fiber length of 6 to 12 mm because a homogeneous thermoplastic carbon fiber reinforced composite material can be obtained.

The amount of the thermoplastic resin and the carbon fiber to be supplied is controlled within the above range since the thermoplastic resin contains 10 to 100 parts by weight per 100 parts by weight of the carbon fiber, which contributes to high strength and high elasticity, thereby maximizing the mechanical properties.

In the present invention, a homogeneous thermoplastic carbon fiber-reinforced composite material is produced by a continuous process using a double belt press which is hardly applied to the prior art.

In the step ii), if the thermoplastic resin is crystalline, it is melted at a temperature higher than the melting point of the thermoplastic resin, or if the thermoplastic resin is amorphous, it is melted at a temperature higher than the glass transition temperature.

In the step iii), the impregnation property of the thermoplastic resin to the carbon fiber is increased by cooling (isobaric press) the melted thermoplastic resin to obtain the thermoplastic resin matrix on the film.

Finally, by solidifying with the cooling rollers in the step iv), a uniform thermoplastic carbon fiber-reinforced composite material having no air pocket and a constant thickness can be mass-produced.

The process speed operated by the double belt press through steps i) to iv) may vary depending on processing conditions including the melting temperature, but is preferably performed at a speed of 0.2 to 0.5 m / min.

Hereinafter, specific examples will be described in detail (see FIG. 5).

( Example )

2.5 kg of a thermoplastic polyurethane resin sheet and 5 kg of carbon fiber (carbon fiber having a fiber length of 12 mm) were fed to a double belt press at a preset feed rate. The thermoplastic polyurethane resin sheets were melted in fixing rollers at 258 캜 and 259 캜, and then conveyed through circulating rollers. Subsequently, the film was pressurized at 60 DEG C and 70 DEG C under an isostatic pressure (4 MPa) to impregnate the film-like thermoplastic polyurethane resin into the carbon fibers. Finally, a thermoplastic carbon fiber-reinforced polyurethane composite material was prepared by solidification on a cold roller set at 40 DEG C, and the entire process was performed at a rate of 0.25 m / min.

The thermoplastic carbon fiber-reinforced polyurethane composite material according to the present invention can be manufactured by hot stamping molding as shown in FIG. 6, using the thermoplastic carbon fiber reinforced composite material as a precursor, Various types of plastic molded articles can be produced at a high speed within one minute.

Claims (10)

delete delete delete i) feeding the thermoplastic resin matrix on the film and the carbon fiber together into a double belt press;
ii) transferring the thermoplastic resin through the circulating roller after melting the thermoplastic resin in the fixing roller;
iii) pressing the melted thermoplastic resin under an isostatic pressure to impregnate the carbon fiber with the film-like thermoplastic resin; And
and iv) solidifying the mixture on a chill roller. 5. The method of claim 4, wherein the thermoplastic resin is selected from the group consisting of thermoplastic polyurethane, polyurethane, polyamide, polyethylene, polypropylene, polystyrene, polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, polyvinyl acetate, acrylonitrile- Acrylonitrile-butadiene-styrene copolymer, acrylic resin, methacrylic resin, polyacetal, polycarbonate, polyarylate, polysulfone, polyethersulfone, polyetheretherketone, polylactide, polyphenylene sulfide, Wherein the thermoplastic resin is any one selected from the group consisting of polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, and polybutylene naphthalate. 5. The method of claim 4, wherein the carbon fiber is a carbon fiber cloth having a thickness of 3K to 48K or a carbon fiber cloth having a length of 6 to 12 mm. The method for producing a thermoplastic carbon fiber-reinforced composite material according to claim 4, wherein the thermoplastic resin contains 10 to 100 parts by weight based on 100 parts by weight of the carbon fiber. The method for producing a thermoplastic carbon fiber-reinforced composite material according to claim 4, wherein the thermoplastic resin in step ii) is melted at a temperature higher than the melting point of the thermoplastic resin or at a temperature higher than the glass transition temperature. 5. The method of claim 4, wherein the steps i) to iv) are performed at a rate of 0.2 to 0.5 m / min. A method for producing a plastic molded article by hot stamping molding a thermoplastic carbon fiber-reinforced composite material produced by the method of any one of claims 4 to 9.

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