CROSS REFERENCE TO RELATED APPLICATIONS

This application is a National Stage of International Application No. PCT/KR2018/011106 filed Sep. 20, 2018, claiming priority based on Korean Patent Application Nos. 10-2017-0126197 filed Sep. 28, 2017 and 10-2017-0165779 filed Dec. 5, 2017.

TECHNICAL FIELD

The present disclosure relates to an aramid fabric having excellent adhesion to a polyurethane matrix resin and excellent tensile strength, a method for producing the same, an aramid fabric prepreg including the same, and an aramid fabric/thermoplastic polyurethane resin composite including the same, and more particularly, to an aramid fabric which can increase the cohesion of aramid yarns constituting the aramid fabric and thus enhance the tensile strength of the aramid fabric, can improve weaving performance without causing the a dropping phenomenon of size during weaving, and can enhance the adhesion to a polyurethane matrix resin, and to a method for producing the same.

The present disclosure also relates to an aramid fabric prepreg in which the aramid fabric is impregnated with a polyurethane matrix resin in an uncured or semi-cured state.

The present disclosure further relates to a composite composed of an aramid fabric/thermoplastic polyurethane matrix resin that is excellent in impact resistance, tensile strength, and tensile elastic modulus by including the aramid fabric.

BACKGROUND ART

As electronic part materials or automotive part materials, a reinforcing fiber material/resin composite (hereinafter referred to as “composite”) in which a polyurethane matrix resin is impregnated and cured in a reinforcing fiber material have been widely used.

Glass fiber has been used as the reinforcing fiber material, but the glass fiber has a high specific gravity, which makes it difficult to reduce weight, and there is a problem that it is harmful to the human body.

In another conventional technique, in order to solve such a problem, carbon fiber has been used instead of glass fiber as the reinforcing fiber material, but the carbon fiber has a problem that non-rigidity is large, and thus processability and impact resistance are reduced.

As yet another conventional technique, an aramid fabric woven with a plain weave has been mainly used as a reinforcing fiber material, but the aramid fabric woven with the plain weave has poor wetting properties with polyurethane matrix resins, and aramid yarns constituting the conventional aramid fabric have a problem that the compatibility with the polyurethane matrix resin is reduced, which results in a decrease in adhesion between the aramid fabric and the polyurethane matrix resin, and further, there was a problem that the cohesion between the yarns constituting the aramid fabric is insufficient and thus the tensile strength of the aramid fabric is reduced.

DETAILED DESCRIPTION OF THE PRESENT DISCLOSURE

Technical Problem

It is an object of the present disclosure to provide a method for producing an aramid fabric which has an excellent wetting property with the polyurethane matrix resin impregnated into the aramid fabric, resulting in excellent adhesion between the aramid fabric and the polyurethane matrix resin, and at the same time increasing the cohesion of yarns in the aramid fabric and exhibiting excellent tensile strength of the aramid fabric, and thus is useful as a fiber-reinforced composite material.

It is another object of the present disclosure to provide an aramid fabric which is produced by the above method and which has excellent adhesion to a polyurethane matrix resin and excellent tensile strength, and an aramid fabric prepreg including the same.

It is still another object of the present disclosure to provide an aramid fabric/thermoplastic polyurethane matrix resin composite which is excellent in tensile strength and tensile elastic modulus and is also particularly excellent in impact resistance, and thus is useful as automotive part materials requiring excellent impact resistance.

Technical Solution

In order to achieve the above objects, in one aspect of the present disclosure, an aramid fabric having excellent adhesion to a polyurethane matrix resin and excellent tensile strength is produced by a method including the steps of: (i) weaving a basket weave aramid fabric by using aramid yarns as warp and weft yarns; and (ii) dipping the woven aramid fabric in a sizing agent solution composed of an aqueous polyurethane resin as a sizing agent and water, followed by squeezing and drying, thereby attaching and impregnating the sizing agent solution onto the aramid fabric, wherein the content of the aqueous polyurethane resin attached to and impregnated into the surface and the inside of the aramid fabric is adjusted to 1 to 8% by weight, based on the sum total of the weight of the aqueous polyurethane resin attached to and impregnated into the surface and the inside of the aramid fabric and the weight of the aramid fabric before the aqueous polyurethane resin is attached and impregnated.

In another aspect of the present disclosure, an aramid fabric/thermoplastic polyurethane matrix resin composite is produced by using two or more basket weave aramid fabrics in which an aqueous polyurethane resin is attached/impregnated onto the surface and inside as a reinforcing fiber material constituting an aramid fabric/thermoplastic polyurethane resin composite, and using a thermoplastic polyurethane resin as the matrix resin constituting the composite.

Advantageous Effects

In the present disclosure, since the sizing agent is applied to the woven aramid fabric, it is possible to effectively prevent deterioration in weaving efficiency due to the dropping of size agents during weaving, compared with a method in which a sizing agent is applied to an aramid yarn before weaving.

Additionally, in the present disclosure, since an aqueous polyurethane resin is attached to or impregnated into a surface and the inside of the aramid fabric, the adhesion of the aramid fabric to a polyurethane matrix resin is improved and the cohesion of aramid yarns in the aramid fabric is increased, so that the tensile strength of the aramid fabric is enhanced.

Furthermore, in the present disclosure, since the aramid fabric is woven in a basket weave, compactness of the aramid fabric is lowered and the wetting property of the aramid fabric with the polyurethane matrix resin is improved, and as a result, the adhesion between the aramid fabric and the polyurethane matrix resin is enhanced.

Consequently, the aramid fabric produced according to the present disclosure is useful as a reinforcing fiber material for the production of reinforcing fiber materials/resin composites used in electronic part materials and the like.

Further, since the aramid fabric/thermoplastic polyurethane resin composite of the present disclosure is an aramid fabric whose reinforcing fiber material is excellent in impact resistance, it is useful as an automobile part material such as an automobile bumper or an electronic part material which requires impact resistance.

