KR102276413B1 - Resin composition for mobile display device bracket comprising carbon fiber composite resin and mobile display for mobile using the same - Google Patents

Abstract

The present invention relates to a resin composition for a mobile display device bracket including a carbon fiber composite resin and having excellent mechanical properties, and a mobile display device using the same. Particularly, a carbon fiber composite resin prepared from a phenoxy composite resin composition forming a composite with carbon short fibers having a length of 1-6 mm as a reinforcing material is used alone or in combination with conventional polyamide, or the like, to provide improved adhesion with a polyurethane-based adhesive. In addition, when the resin composition is used for a mobile bracket, the composition shows excellent adhesiveness and durability. The resin composition for a mobile display device bracket including a carbon fiber composite resin according to the present invention includes a carbon fiber composite resin prepared from a carbon fiber composite resin composition including a phenoxy polymer resin and carbon short fibers having a predetermined length.

Description

Resin composition for mobile display bracket containing carbon fiber composite resin and display device for mobile using the same

The present invention relates to a resin composition for a mobile display bracket comprising a carbon fiber composite resin having excellent mechanical properties and a mobile display device using the same, and more particularly, it can improve adhesion with a polyurethane-based adhesive, and It relates to a resin composition for a mobile display bracket comprising a carbon fiber composite resin having excellent adhesion and durability when used as a resin composition for brackets, and to a mobile display device using the same.

In general, the most common structure of a composite material consists of two elements: a matrix, which functions as a bonding material, and a filler, which functions as a reinforcing material. ) refers to a composite material that acts as a matrix.

Among these composite resins, the most widely used composite resin uses continuous fibers with high strength and high modulus of elasticity as reinforcing materials, which include thermosetting resins (epoxy, unsaturated polyester, phenol formaldehyde, polyimide, etc.) or thermoplastic resins (polyester, Nylon, polypropylene, polyethylene, etc.) contains at least one glass fiber, carbon fiber, ceramic fiber, and metal fiber, etc., but these composite resins have a high cost of raw material fiber and a complicated manufacturing process. There is a disadvantage of being used very limitedly for aerospace and defense purposes.

Nevertheless, the demand for composite resins is expanding from the conventional aerospace and defense fields to various industrial fields ranging from automobiles and daily general household items to the present, and accordingly, the dissemination technology is urgently required. In particular, it is complex due to the demand for lightweight materials as well as excellent mechanical properties such as high tensile strength, fracture toughness and impact strength in fine parts of automobiles, exterior or parts of IT devices such as mobiles, and parts for various home appliances or building materials. The need for resin is increasing.

However, in the case of a conventional composite resin using continuous fibers as a reinforcing material, since it has a one-way orientation, the elastic modulus and strength of the composite resin are highest only in the orientation direction of the fibers. Therefore, it has no resistance at all to the external force applied in the vertical direction of the fiber and only resists the resin acting as a matrix. As a result, the mechanical properties are very low, and the unidirectional composite resin has a very large mechanical anisotropy.

In addition, most of the composite resin uses a thermosetting resin as a matrix resin for supporting the fibers in order to compensate for the disadvantages of unidirectional anisotropy as described above. Once hardened, it does not melt even when heated, so it is difficult to recycle. Most of these composite resins are currently being treated in a landfill method, which is economically wasteful and may cause serious environmental pollution.

As a typical use example of such a thermosetting matrix resin, there is an epoxy resin, and the epoxy resin is a thermosetting resin composed of a network polymer formed by ring opening of the epoxy group generated when an epoxy monomer having two or more epoxy groups in the molecule is mixed with a curing agent. It has excellent resistance and durability to chemical components and has a low volumetric shrinkage during curing, so it is used as an essential high-functional raw material in the field of composite materials. However, as a thermosetting resin, epoxy resin forms a three-dimensional cross-linked structure after curing, and this structure has the advantage of imparting excellent durability and corrosion resistance to the material. It also has the disadvantage of being very difficult to recycle.

In order to solve this problem, in recent years, as part of an effort to use a thermoplastic resin for a composite resin without using a thermosetting resin, a technology using a polypropylene (PP) resin has been steadily developed. It is well known that thermoplastic resins are more environmentally friendly than thermosetting resins because they can be recycled through a heating process and can be re-molded into various new parts. In addition, thermoplastic resins have advantages such as excellent processability, low unit cost, and high tensile strength. Because of this, it is one of the promising materials as a matrix resin for composite resins.

However, thermoplastic resins have a more fundamental problem in that overall mechanical properties are lower than those of thermosetting resins. In particular, when a reinforcing material having almost no functional groups on the surface such as carbon fibers is used, most thermoplastic resins also lack functional groups capable of chemical bonding, so the interfacial bonding force between carbon fibers and thermoplastic resins is inevitably low, resulting in low mechanical strength. is recognized as a fundamental weakness of carbon fiber reinforced thermoplastic composites. In order to improve this weakness, a so-called sizing agent or a surface treatment agent simply called sizing or size is usually used on the surface of the reinforcing material.

On the other hand, in general, since a silane compound has many functional groups, that is, a large number of active binding sites, a silane coupling agent is most widely used and can be easily applied to the surface. The silane is specially selected so that its organic functional groups can chemically interact with the matrix resin, thus improving the adhesion between the reinforcing material and the matrix. However, the silane compound has a low molecular weight, so it is easy to decompose or liberate from the surface of the reinforcing material in the post-process for manufacturing a composite resin such as a high-temperature impregnation process or curing process, and furthermore, the interfacial layer is resistant to external stress at the nano-meter level. It is difficult to exert an elastic force against a resisting interfacial shear force. To compensate for this, the surface of the reinforcing material may be oxidized by a method such as plasma treatment, corona discharge or wet electrochemical treatment to increase the oxygen functional group density, thereby increasing the adhesion effect of the silane compound or the sizing composition.

In this regard, in Korea Patent Publication No. 10-2017-0026741, in order to improve the mechanical properties of the thermoplastic carbon fiber composite resin, the surface of the carbon fiber is treated with nitric acid, surface roughness is induced, and then the thermoplastic resin is treated with a silane compound. A method for improving mechanical strength by increasing the interfacial bonding force with However, according to this, the surface treatment time is long and complicated, and productivity is reduced or environmental problems are easy to occur in that a chemical such as nitric acid is used, and in the case of a silane compound, as described above as a material in a monomolecular state, In a high-temperature molding process such as prepreg, organic thermal decomposition is caused rather than causing a problem in the possibility of molding defects.

In addition, in Korean Patent Application Laid-Open No. 10-2017-0121920, the interfacial bonding force is also increased by adjusting the evaporation rate of the solvent during processing by using a soluble solvent of the thermoplastic resin to adhere the crystalline form of the thermoplastic resin to the carbon fiber surface. Although it is suggested to use a method to improve the mechanical strength of the composite resin, this also requires time required to control the evaporation rate of the solvent and additional process cost, and when there is a solvent remaining on the carbon fiber surface, It is easy to cause void defects in the subsequent heat treatment process and has a problem in that it may cause a decrease in interfacial bonding strength.

In addition, in the above methods, the carbon fiber surface is activated by wet chemical treatment (nitric acid, solvent, etc.) or dry chemical treatment (eg, CVD, powder coating) to settle the sizing compound on the fiber surface. It not only causes difficulties in handling, but also has a problem of lowering storage stability.

On the other hand, in the case of conventional synthetic wood, because wood powder, which basically serves as a reinforcing material, is hydrophilic, it is difficult to mix and match with a hydrophobic plastic resin, and thus, there is a fundamental technical limitation in that it is difficult to secure sufficient durability.

A number of prior literatures for improving this problem have been disclosed, for example, methods using a so-called compatibilizer such as a maleic anhydride-containing polymer are common. More specifically, in the composition constituting synthetic wood in Korean Patent Publication No. 1175308, Registered Patent Publication No. 1113114, Registered Patent Publication No. 0250643 and Registered Patent Publication No. 0681333, mainly compatibilization of plastic resin and wood powder ) to improve the durability of synthetic wood by increasing the interfacial bonding force.

However, it is still difficult to remarkably improve the low structural strength of synthetic wood resulting from the incompatibility between wood flour and plastic resin according to the above prior documents, and in particular, the carbonization point (175°C) of wood flour is the melting point of plastic resin (180~ 230 ℃), if the wood powder is carbonized during processing, it is a problem that causes deterioration of the quality of synthetic wood and a decrease in productivity.

In addition, in order to satisfy the bezel-less requirement of liquid crystal glass to realize a wider screen in mobile devices including smartphones, it is required to minimize the area where the liquid crystal glass and the bracket are bonded. The width is required to be less than 1mm from the level of 5mm or more in the prior art, and the width of the adhesive for bonding it is also inevitably required to be miniaturized.

Accordingly, a technique of applying a polyurethane adhesive with excellent elasticity in a fine width is being actively studied, but the adhesive strength between nylon (PA) or butylene terephthalate (PBT), which is a bracket material, and the polyurethane adhesive is low, so assembly reliability and Durability is an issue.

In this regard, Korean Patent Application Laid-Open No. 10-2004-0101650 describes a method of modifying the plastic surface as a pretreatment process before the bonding process in order to improve the bonding strength, but a process for modifying the surface of the nylon material is added. Accordingly, the process efficiency is lowered, and the technically short Life time for maintaining the adhesive force causes a problem in that the adhesive performance deteriorates after a certain period of time has elapsed. In addition, to improve adhesion, US 2006/0084755 includes isocyanates and block acrylic copolymers, wherein the isocyanates include polymeric isocyanates or isocyanate-terminated prepolymers to further enhance the reactivity of the polyurethane prepolymers and thereby non-polar Although the bonding strength with the adherend having a surface is improved, the surface adhesion strength is prone to deviation depending on the yield of functional groups participating in the curing reaction, and due to the increase in the degree of crosslinking due to the rapid reaction rate and the resulting change in viscosity, it is still It is difficult to improve the discharge defect.

Accordingly, there is still a need for improvement in the known composite resins, and there is still a need for a solution that can secure mechanical properties while being more easily molded.

Korean Patent Publication No. 10-2017-0026741 Korean Patent Publication No. 10-2017-0121920 Korean Patent Publication No. 1175308 Korean Patent Publication No. 1113114 Korean Patent Publication No. 0250643 Korean Patent Publication No. 0681333 Korean Patent Publication No. 10-2004-0101650 US Patent Publication No. 2006/0084755

The present invention has been devised to solve the above problems, and the problem to be solved by the present invention is to use a carbon fiber composite resin prepared from a phenoxy composite resin composition in which short carbon fibers having a length of 1 to 6 mm are composited as a reinforcing material. Alternatively, by mixing with a conventional polyamide, etc., adhesion with a polyurethane-based adhesive can be improved, and when used as a resin composition for mobile brackets, a resin composition for a mobile display bracket comprising a carbon fiber composite resin having excellent adhesion and durability and to provide a mobile display device using the same.

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

The above object includes a carbon fiber composite resin, wherein the carbon fiber composite resin includes a phenoxy polymer resin according to Formula 1 and a short carbon fiber,

(Formula 1)

Here, n is an integer of 1 to 100, prepared from the carbon fiber composite resin composition, achieved by a resin composition for a mobile display bracket comprising a carbon fiber composite resin.

Preferably, the phenoxy polymer resin may have a weight average molecular weight of 10,000 to 70,000 g/mol.

Preferably, the short carbon fibers may have a length of 1 to 6 mm.

Preferably, it may contain 10 to 200 parts by weight of short carbon fibers relative to 100 parts by weight of the phenoxy polymer resin.

Preferably, the carbon fiber composite resin may be obtained in the form of pellets or sheets or films through extrusion molding.

Preferably, the resin composition for the bracket may further include a thermoplastic resin or a thermosetting resin.

Preferably, it may contain 10 to 100 parts by weight of the resin composition for brackets relative to 100 parts by weight of the thermoplastic resin or thermosetting resin.

Preferably, the carbon fiber composite resin composition may further include a curing agent such as urea, isocyanate, and melamine.

In addition, the above object is achieved by a mobile display device manufactured using the resin composition for a mobile display device bracket containing the carbon fiber composite resin described above.

According to the present invention, by mixing a thermoplastic phenoxy polymer resin with excellent adhesion with short carbon fibers, it is possible to contribute to the popularization technology of composite resin by providing a novel composite resin with excellent mechanical properties as well as excellent moldability. It works.

In addition, according to the present invention, due to the thermal properties of the phenoxy polymer resin, there is an improvement effect in economic and environmental aspects by providing excellent recycling properties as a matrix resin.

In addition, according to the present invention, it is possible to provide a carbon fiber composite resin having heat dissipation, lightness and corrosion resistance having three-dimensional isotropy.

In addition, according to the present invention, the mechanical strength of synthetic wood can be improved by strengthening the interfacial bonding force between wood powder and resin in synthetic wood (wood-plastic composite), and when used as a synthetic wood exposed to the outside, shrinkage and expansion due to heat There is almost no distortion after construction, and this has the effect of reducing the hassle and cost of re-construction due to distortion.

In addition, according to the present invention, as a reinforcing material, by using a phenoxy composite resin composition in which short carbon fibers having a length of 1 to 6 mm are used alone or by mixing with conventional polyamide, etc., adhesion with a polyurethane-based adhesive can be improved, and the mobile bracket When used as a resin composition for use, there are effects such as having excellent adhesion and durability.

In addition, according to the present invention, by using the carbon fiber composite resin as a compatibilizer in the blend or alloy of the waste plastic resin, excellent single physical properties can be realized, and technical effects such as being able to provide excellent recyclability of the waste plastic resin there is

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

1 is a view comparing the orientation of short carbon fibers in a carbon fiber composite resin according to an embodiment of the present invention.
2 is a conceptual diagram showing hydrogen bonding between the phenoxy polymer resin of the carbon fiber composite resin and cellulose, which is a main component of wood flour, according to an embodiment of the present invention.
3 is a view for explaining a process of adhering liquid crystal glass and a bracket in a smartphone using a resin composition for a bracket for a mobile display device according to an embodiment of the present invention.

Embodiments of the present invention will be described in detail so that those of ordinary skill in the art to which the present invention pertains can easily implement them. However, the present invention may be embodied in many different forms and is not limited to the embodiments described herein.

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

The carbon fiber composite resin composition according to the first aspect of the present invention and the carbon fiber composite resin according to the second aspect of the present invention may include a phenoxy polymer resin and a chopped carbon fiber.

The present inventors envisioned a compound-type composite resin having carbon fibers in the form of particles as a method for improving the recyclability problem of the conventional thermosetting composite resin and the low moldability and low mechanical strength of the thermoplastic composite resin, As a result of intensive research, the present invention was completed by focusing on compounding short carbon fibers with a thermoplastic phenoxy polymer resin. Accordingly, the carbon fiber composite resin prepared with the carbon fiber composite resin composition according to the present invention can secure basically excellent mechanical strength, heat dissipation with three-dimensional isotropy, lightness and corrosion resistance due to the reinforcement of short carbon fibers.

The orientation of the present invention will be described with reference to FIG. 1, which is a diagram comparing the orientation of short carbon fibers in the carbon fiber composite resin according to an embodiment of the present invention. The cube in FIG. 1 shows the carbon fiber composite resin for convenience, and is only for explaining the concept.

In general, composite resins that are not materials such as metals made of single particles have anisotropy that changes their physical properties along the axis. Fiber, which is a reinforcing material, is an anisotropic material and exhibits the strongest strength in the fiber length direction. Therefore, the type of dispersion or arrangement of fibers inside the composite resin is an important issue underlying the design of composite resins. There are three basic types of fibers with short fiber length: unidirectional orientation (FIG. 1 (a)), two-dimensional irregular orientation (FIG. 1 (b)), and three-dimensional irregular orientation (FIG. 1 (c)). , 3D isotropy is obtained as it goes to a 3D irregular orientation, and the more the composite resin has isotropy, the more uniform physical properties are secured.

Therefore, according to the present invention, short carbon fibers (2) having a length of 1 to 6 mm so that the short carbon fibers are three-dimensionally irregularly oriented in the phenoxy polymer resin (1), which is the matrix resin, as shown in FIG. -1, 2-3, 2-6), and can be mixed by length, but the ratio of the mixing amount is not particularly limited. For example, 10 parts by weight, 50 parts by weight, and 40 parts by weight can be added by dividing the total weight of carbon short fibers into 1mm, 3mm, and 6mm by length, more preferably 1mm, 3mm, and 6mm divided into 30 parts by weight, respectively. Parts, 40 parts by weight, and 30 parts by weight can be added. In this way, when short carbon fibers (2-1, 2-3, 2-6) are added by length, the length of the carbon fiber, which is a reinforcing material, is remarkably shortened. Not only the impregnation property is remarkably improved, but also the molding of light, thin, short and small parts having various shapes is facilitated.

At this time, when the length of the short carbon fibers is less than 1 mm, aggregation of the short carbon fibers occurs and it is difficult to be dispersed in the matrix resin, and when it exceeds 6 mm, the one-way to two-dimensional irregular orientation is easy to be made rather than the three-dimensional irregular orientation. However, there is a possibility that multiple aggregation occurs between the fibers.

In addition, in manufacturing a composite resin for reinforcing short carbon fibers, it is very important to secure an excellent matrix resin. In particular, in order to reinforce the weak interface between the short carbon fibers and the thermoplastic matrix resin, a large amount of functional groups should exist on the polymer resin chain and the matrix resin itself should have excellent mechanical properties. When using conventional thermoplastic resins including polypropylene, it is difficult to achieve the above object due to insufficient functional group distribution and low resin strength.

The present inventors have completed the present invention by focusing on a phenoxy polymer resin, which is a polymer resin having a structure that is basically thermoplastic as a matrix resin and can be selectively thermally cured at the same time. This phenoxy polymer resin is a thermoplastic resin, a polyhydroxy ether obtained by the reaction of bisphenol A and chlorohydrin. It is a high molecular weight resin of about n = 100, similar to an epoxy resin, but does not have an active epoxy group at the molecular terminal and is an epoxy resin. It is a polymer that is much larger than resin and has another characteristic in that it is thermoplastic.

In general, phenoxy polymer resins have excellent adhesion to an adherend and mechanical properties, have low molding shrinkage, and have very low gas, especially oxygen permeability among plastic resins, and are mostly used as molding materials and paints. In addition, since it has a hydroxyl group in the molecule, even though it is a thermoplastic resin, when isocyanate, urea, melamine, etc. are used as a curing agent, a cross-linked structure is formed by forming a cross-linked structure depending on the purpose of use. It has the characteristic that compatibility with thermosetting resin can be improved easily.

In one embodiment, the phenoxy polymer resin may be a phenoxy polymer resin according to Formula 1 below.

(Formula 1)

Here, n is an integer from 1 to 100.

The phenoxy polymer resin according to Formula 1 is a polyhydroxy polyether synthesized from bisphenols and epichlorohydrin, and corresponds to a thermoplastic resin. In addition, the structure of the phenoxy polymer resin of Formula 1 contains a hydroxyl group in the repeating molecular chain, giving excellent adhesion to the carbon fiber, and a large amount of hydroxyl groups between the carbon fiber and the matrix resin It has excellent interfacial bonding strength by distributing it at the interface of

In addition, the phenoxy polymer resin according to Chemical Formula 1 has high gas barrier properties because the molecular unit is repeated to have polyol properties, so it is possible to secure excellent moisture resistance and storage stability until it is complexed with a matrix resin to form a final shape. In addition, the final molded parts produced therefrom can ensure durability even in harsh conditions of high temperature and high humidity.

In addition, the phenoxy polymer resin according to Formula 1 includes a bis-phenol structure in the center, and has high heat resistance, durability, and high tensile strength due to this structure. For this reason, the phenoxy matrix resin according to an embodiment of the present invention provides excellent durability to the composite resin.

In addition, since the phenoxy polymer resin according to Formula 1 has a structure including an ether group, it has high chemical resistance, and has excellent processing properties as a composite material by providing low melt viscosity and chain flexibility. Conjugation of short carbon fibers can be made more easily.

In one embodiment, the phenoxy polymer resin of Formula 1 preferably has a weight average molecular weight of 10,000 to 70,000 g/mol, more preferably 20,000 to 50,000 g/mol. If the weight average molecular weight of the phenoxy polymer resin is less than 10,000 g/mol, the melt viscosity is too low, so it is difficult to control the ejection amount during extrusion when compounding short carbon fibers. If the weight average molecular weight exceeds 70,000 g/mol, the melt viscosity will decrease. Because it is too high, it is difficult to control the discharge amount, and it is difficult to mix the short carbon fibers and it is difficult to increase the mixing ratio.

In the case of the phenoxy polymer resin constituting the carbon fiber composite resin according to the present invention, it is possible to use the resin alone, but it is more preferable to have the form of a composite resin. For example, it is possible to simply replace the thermoplastic or thermosetting plastic resin used in the conventional carbon fiber reinforced plastic (CFRP) with the phenoxy polymer resin of the present invention, but structural stress in various environments in which the composite resin is used Considering that, it is most preferable to have the form of a composite resin.

In one embodiment, the short carbon fibers preferably have a length of 1 to 6 mm, and more preferably have a length of 3 to 6 mm. When the length of the short carbon fiber is less than 1 mm, the short carbon fiber tends to be in the form of a powder, resulting in agglomeration of the short fiber, which makes it difficult to uniformly disperse in the phenoxy polymer resin, and when it exceeds 6 mm, the short carbon fiber in the width direction This is because multiple aggregation occurs, which also makes it difficult to uniformly disperse in the phenoxy polymer resin.

In one embodiment, it is preferable to blend 10 to 200 parts by weight of short carbon fibers relative to 100 parts by weight of the phenoxy polymer resin, more preferably 20 to 100 parts by weight, more preferably 40 to 80 parts by weight desirable. If the blending amount of short carbon fibers is less than 10 parts by weight, it is difficult to express the strength of the composite resin, and if it exceeds 200 parts by weight, ejection may not be smooth during extrusion or the short carbon fiber mixing process may not be smooth.

In one embodiment, the short carbon fibers may be sized, and the sizing material is not particularly limited to a low molecular weight thermosetting resin or a thermoplastic resin. By sizing the short carbon fibers in this way, it is possible to facilitate the dispersion of the short carbon fibers in the phenoxy polymer resin in the compounding process. Here, the mixing process is possible as long as it is a stirring mixer capable of applying heat and is not particularly limited.

In one embodiment, the carbon fiber composite resin may be obtained in the form of pellets or sheets or films through extrusion molding. That is, a conventional Henschel mixer, a super mixer, or a dispersion kneader is used to mix a phenoxy polymer resin and a short carbon fiber or to make a lump dough, then a melt extrusion molding process using a conventional single or twin extruder It may be an intermediate substrate obtained in the form of a pellet or obtained in the form of a sheet or film through an extrusion mold.

In one embodiment, in the process of mixing the phenoxy polymer resin and the short carbon fiber, 10 to 200 parts by weight of the short carbon fiber relative to 100 parts by weight of the phenoxy polymer resin at 180 to 200° C. for 80 to 120 minutes, 120 to 150 m It is preferable to mix at a rotation speed of /s, and if it is out of the mixing conditions, the dispersibility of short carbon fibers is lowered or there is a problem in that the mixing characteristics are reduced due to overheating of the sizing agent, so it is better to mix under the above mixing conditions more preferably.

After mixing in this way, depending on the purpose of use of the carbon fiber composite resin, it can be obtained in the form of pellets or in the form of sheets or films through extrusion, and the temperature of the extruder can be set to 180 to 230°C. The extrusion molding method is in accordance with conventional conventional apparatus usage well known to those skilled in the art, and is not particularly limited.

When the carbon fiber composite resin according to the present invention is obtained in the form of a sheet or film, the prepreg using the conventional thermoplastic matrix resin is replaced alone or prepreg is impregnated by directly pressing the sheet with the carbon fiber in the form of a fabric at high temperature. It can be used as an intermediate bonding material when stacking legs. Conventionally, in the case of manufacturing a prepreg using a thermoplastic resin, the melt of the thermoplastic resin is directly applied on the carbon fiber on the fabric by extrusion and then impregnated using a hot roller. High temperature of 200°C or higher is required for impregnation. At this time, tar generation due to oxidation reaction at high temperature is severe, there is stickiness, and air pockets are defective due to high viscosity. There were many difficulties.

However, when the carbon fiber composite resin according to an embodiment of the present invention is obtained in the form of a sheet or film, the intermediate substrate is melted and impregnated into the carbon fiber by bonding the sheet and the carbon fiber together and then heating and pressing it to prepreg alone. Alternatively, the prepreg can be prepared by further impregnating the thermosetting or thermoplastic matrix resin on the prepreg according to the conventional method, and when the prepreg is obtained in this way, the carbon fiber composite resin according to an embodiment of the present invention is impregnated. The temperature may be about 180 ° C. or less, and molding is possible at a lower temperature than the method using an extruder, and the method of impregnating the matrix by extruding the thermoplastic resin may also be applied in the same manner as described above.

As described above, by generating a stronger interfacial bonding force between the carbon fiber and the matrix resin by inter-diffusion between the phenoxy polymer resin and the thermosetting or thermoplastic matrix resin in the carbon fiber composite resin according to an embodiment of the present invention It becomes possible to manufacture high-quality prepregs.

In addition, thermosetting resins, such as epoxy resins, are supplied as a solution in the form of a monomer having a low viscosity, and after being impregnated in a reinforcing material, the curing agent included in the solution composition is heated to a temperature at which curing starts, thereby producing a final molded article. As a method of impregnating such a thermosetting matrix resin on a reinforcement, it can be applied, for example, by a mechanical application method, for example, using a caulking gun or any other manual application means; application using swirl technology using, for example, pumps, control systems, dosing gun assemblies, remote feeding devices and application guns; It can also be applied using the steaming method. Also in general, this temperature may be from about 80°C or higher or about 100°C or higher to about 220°C or lower or about 180°C or lower, using a single curing cycle or multiple curing cycles, a curing temperature of about 220°C or even 180°C or lower. can be applied.

The carbon fiber reinforced plastic prepreg according to the third aspect of the present invention is a carbon fiber composite resin impregnated with the above-mentioned carbon fiber fabric, and the carbon fiber reinforced plastic according to the fourth aspect is obtained by using the above-described carbon fiber composite resin composition. It may include a formed adhesive layer.

When the carbon fiber composite resin according to an embodiment of the present invention is in the form of a sheet or film, a prepreg is prepared by compressing the reinforcing material and the sheet or film, and then combining the thermosetting matrix resin, and then finally curing the composite article. can be manufactured.

According to the present invention, the conventional conventional impregnation methods are not particularly limited, but preferably, after bonding the carbon fiber composite resin according to the present invention to the reinforcing material, the epoxy resin composition is heated as a matrix resin to reduce its viscosity, The carbon fiber composite resin according to the present invention is directly applied to the reinforcing material to which the carbon fiber composite resin is bonded to obtain a resin-impregnated prepreg, or an epoxy resin composition is applied to a release paper to obtain a thin film, and then the thin film is heated and pressured to obtain a carbon fiber according to the present invention. A method of pressing on both sides of the reinforcing material sheet to which the composite resin is bonded may be used. Thereafter, for example, a vacuum bag in an oven equipped with an autoclave and a vacuum line can be used. In the autoclave method, the layer is compressed by applying pressure, and in the vacuum bag method, the vacuum bag is introduced into the bag when the part is cured in an oven. rely on pneumatic The autoclave method can be used for large, high-quality composite parts such as automobiles and ships.

According to the present invention, in addition to the above methods, filament winding, pultrusion molding, resin injection molding and resin transfer molding/resin injection, vacuum assisted resin transfer molding, or an equivalent or similar method may be used, but is not limited thereto.

Since the phenoxy polymer resin of the carbon fiber composite resin composition according to the present invention has a structural similarity to an epoxy resin mainly used as a thermosetting matrix resin, both have very excellent compatibility with each other. Carbon fiber composite resin can be very usefully used as an intermediate material for bonding the reinforcing material and the matrix resin.

In particular, in the case of an epoxy resin, by forming a crosslink, the compressive strength is strong but the tensile strength or impact strength is weak, so there is a limitation in manufacturing various types of parts. However, when the carbon fiber composite resin according to the present invention is used as an intermediate material, external stress When transferred to this interface, it can function to further improve the durability of the final part by mitigating it and maintaining the bonding force.

In addition, the carbon fiber composite resin according to the present invention can replace the thermosetting matrix resin alone. For example, the phenoxy polymer resin constituting the carbon fiber composite resin of the present invention has a large amount of hydroxyl groups in its chain, so when a curing agent such as an isocyanate compound, urea, or melamine is used, it forms a cross-linked structure and is used as a thermosetting matrix. This is possible.

In addition, the carbon fiber composite resin according to the present invention can improve the recyclability of carbon fiber reinforced plastics using a thermosetting resin as a matrix resin. For example, various methods have been studied to re-obtain carbon fibers from carbon fiber-reinforced plastic waste, but they have not yet yielded remarkable results. However, according to the present invention, since the phenoxy polymer resin, which is an intermediate composition, is thermoplastic, general purpose Since it is easily separated from the carbon fiber by the solvent, the carbon fiber can be easily re-obtained by thermally decomposing the matrix resin and then removing the intermediate substrate by immersion in the solvent.

In one embodiment, the carbon fiber composite resin may be obtained in the form of pellets or sheets or films through extrusion molding. In this case, the sheet or film is preferably formed to a thickness of 1 to 50 mm, and in the case of the film, it is preferably formed to a thickness of 1 mm or less. The thickness of the sheet and film is preferably determined according to the purpose of the user to be constructed, and the present invention is not particularly limited.

In addition, the carbon fiber composite resin according to the present invention can be used alone for a molded article having a large bonding area by obtaining it in the form of a sheet or film, or can be used as a bonding base material for a multi-layered laminated molded article. For example, various applications are possible as a building material bonding part. In particular, the durability, moisture resistance, airtightness, and heat dissipation of short carbon fibers are combined with the excellent adhesion, low gas permeability, and heat resistance of phenoxy polymer resin, so it can be used as an exterior bonding material for moisture permeability.

In addition, when the carbon fiber composite resin according to the present invention is obtained in the form of a sheet or film, it can be used as a material for electronic and electrical components such as a PCB substrate, an IC protection tray, and a wafer protection cassette. For example, in the case of a multi-layered PCB substrate, the composite resin of the present invention can be used to improve heat dissipation by bonding the laminated intermediate substrate to improve the durability of the substrate.

In addition, when the carbon fiber composite resin according to the present invention is obtained in the form of a sheet or film, it can be used as interior and exterior materials for automobiles. For example, by protecting the exterior of an automobile exhaust muffler, corrosion of a metal material can be prevented, and the exterior of various plastic molded articles of the center fascia can be protected.

In addition, when the carbon fiber composite resin according to the present invention is obtained in the form of pellets, it can be used alone or mixed with other plastic resins. When obtained in the form of pellets as described above, the carbon fiber composite resin according to the present invention can be molded alone or mixed with a conventional plastic resin and molded directly into a molded part through an extrusion or injection process. For example, the carbon fiber composite resin according to the present invention can be mixed with a plastic resin used for molding interior and exterior parts such as home appliances and IT devices or molded alone to be used as interior and exterior parts.

Conventionally, thermoplastic and thermosetting resins used for interior and exterior parts such as home appliances and IT devices are difficult to cope with the heat of the device due to the characteristics of the polymer, and this may cause a decrease in reliability due to warpage or deterioration of the parts. prone to occur In addition, in order to increase the impact strength, the resin made of the copolymer has the disadvantage of discoloration or deterioration of physical properties when it comes into contact with oxygen, ozone, or ultraviolet rays in the air, so weather resistance is required. In this case, the carbon fiber composite according to the present invention When the resin is used alone or in combination, it is possible to realize high reliability by increasing the mechanical strength of exterior parts and improving heat dissipation.

The plastic resin mixed with the carbon fiber composite resin according to the present invention and molded into a molded part is not particularly limited as a thermosetting resin or a thermoplastic resin.

In this case, the thermoplastic resin is an olefinic resin, for example, low density polyethylene, linear low density polyethylene, medium density polyethylene, high density polyethylene, polypropylene, polybutylene, polybutene-1, poly-3-methylbutene-1, poly-pentene-1, Poly-4-methylpentene-1, polyisobutylene, polyhexene, ethylene-propylene copolymer, ethylene-butene copolymer, ethylene-pentene copolymer, ethylene-hexene copolymer, ethylene-propylene-diene copolymer, etc. can be used However, in consideration of the heat resistance and recyclability of the blending resin composition, it is preferable to use a polyolefin resin substantially composed of polypropylene, and it is more preferable to use it by mixing with polypropylene or polyethylene.

Preferably, low-density plastics, such as PET, PP, PS, PC, PE, LDPE, LLDPE, etc., high-density plastics, for example, various linear polymers other than HPPE, nylon, various waste vinyls, waste films, etc. and difficult plastics, For example, it may include various plastic materials such as PVC and ABS.

In one embodiment, it is preferable to blend 10 to 100 parts by weight of the carbon fiber composite resin according to the present invention relative to 100 parts by weight of the plastic resin. At this time, when the amount is less than 10 parts by weight, the mixing effect is insignificant, and when it exceeds 100 parts by weight, the melting point increases and the moldability may decrease.

The synthetic wood 4 according to the fifth aspect of the present invention may include wood powder and the carbon fiber composite resin described above. That is, the carbon fiber composite resin according to an embodiment of the present invention replaces the plastic binder resin of synthetic wood, which is a wood-plastic composite (WPC) used as interior and exterior materials for building, alone or mixed with a conventional binder resin. can be used by

2 is a conceptual diagram showing hydrogen bonding between the phenoxy polymer resin (1) of the carbon fiber composite resin and cellulose (3), which is a main component of wood flour, according to an embodiment of the present invention.

More specifically, when the carbon fiber composite resin according to an embodiment of the present invention is used alone or mixed with wood flour, cellulose, which is the main component of the wood flour, and the strong hydroxyl group distributed in the phenoxy polymer resin in the carbon fiber composite resin Due to the hydrogen bonding, the interfacial bonding force between the wood powder and the composite resin is strengthened, so that the mechanical strength can be improved. In addition, the carbonization point of the wood powder is lowered due to the high strength and heat dissipation of the carbon fibers (2) in the carbon fiber composite resin, and the carbon fiber Due to the excellent gas permeability of the composite resin, it blocks the corrosion of wood powder, and weather resistance can be expected even when exposed to the external natural environment for a long time.

In one embodiment, when the carbon fiber composite resin is used alone, it may be blended in an amount of 50 to 200 parts by weight of the carbon fiber composite resin compared to 100 parts by weight of wood flour. At this time, when the carbon fiber composite resin is less than 50 parts by weight, the maximum amount of wood powder can be added, but the resin ratio is relatively reduced, so that the mixing function as a binding resin is lowered, and when it exceeds 200 parts by weight, the resin content is relatively reduced. This is because the material content of wood flour may be difficult to implement because the content is excessively increased.

In one embodiment, when mixing the carbon fiber composite resin with the conventional plastic resin for synthetic wood, it is preferable to mix 10 to 100 parts by weight of the carbon fiber composite resin compared to 100 parts by weight of the plastic resin for synthetic wood. If it is less than 10 parts by weight, the mixing effect is insignificant, and if it exceeds 100 parts by weight, the melting point increases and the moldability may decrease.

In one embodiment, the plastic resin for synthetic wood is generally a polyolefin resin, and may be at least one of polypropylene (PP) and polyethylene (ethylene polymers such as HDPE, LDPE, LLDPE) and copolymers thereof or mixtures of these polymers. have.

The resin composition for a mobile display bracket according to the sixth aspect of the present invention is for a mobile display bracket comprising the carbon fiber composite resin composition according to the first and second aspects of the present invention and the carbon fiber composite resin prepared therefrom It may be a resin composition.

3 is a view for explaining a process of bonding liquid crystal glass and a bracket in a smart phone using the resin composition for a bracket for a mobile display device according to an embodiment of the present invention. Referring to FIG. 1 , a resin composition 100 for a bracket for a mobile display according to an embodiment of the present invention is finely applied on a bracket 20 of a smartphone, and liquid crystal glass 10 and a bracket 20 of a smartphone ) is pressed and cured to adhere the liquid crystal glass 10 and the bracket 20 . At this time, the resin composition 100 for a bracket for a mobile display according to an embodiment of the present invention has excellent discharging characteristics along with high adhesion with the bracket 20 made of nylon material, so that it is finely applied to a very narrow portion of the bracket 20 . It can be applied, enabling bezel miniaturization

That is, the resin composition (carbon fiber composite resin) for a mobile display bracket according to an embodiment of the present invention can be used for modifying a non-polar resin such as nylon (polyamide). In general, nylon material is a chain-like polymer connected by amide bonds, and has excellent durability and chemical resistance, but has low surface tension and does not have polar groups on the surface due to inter-internal hydrogen bonding. It is not continuously maintained, and there is a problem in that the adhesive performance deteriorates over time.

In particular, display brackets for mobile devices are currently made of polyamide resin, and PUR (Polyurethane reactive) type polyurethane adhesive used to bond the bracket and liquid crystal display has very low adhesion to polyamide resin, which limits its use. has negative drawbacks.

Accordingly, when the nylon resin is modified with the carbon fiber composite resin according to an embodiment of the present invention, the functional groups of the ether group and polyol structure present in a large amount on the phenoxy polymer resin configured in the composite resin are polyamide and When mixing, the affinity is high and compatibility is good, and as a result, functional group distribution is achieved on the surface. After that, when bonding with a polyurethane-based adhesive, it has very good affinity with the ester group constituting the polyurethane and various functional groups such as polyols and amines. This high and strong interaction results in a remarkably improved adhesion.

In one embodiment, it is preferable to include 10 to 100 parts by weight of the carbon fiber composite resin relative to 100 parts by weight of nylon, and more preferably, the carbon fiber composite resin of the present invention alone is manufactured as a display bracket for mobile. As a result, it is possible to not only improve adhesion with the polyurethane adhesive, but also secure excellent heat dissipation properties for protecting liquid crystals and parts as a display bracket.

The recycled resin composition according to the seventh aspect of the present invention may include the carbon fiber composite resin composition according to the first and second aspects of the present invention and the carbon fiber composite resin and waste plastic resin prepared therefrom. That is, the carbon fiber composite resin according to an embodiment of the present invention can be used as a resin compatibilizer and strength improver for recycling waste plastics.

In general, in the case of general-purpose waste plastics such as PET, PP, PE, and PVC, which are recycled composite resins, there is not enough functional group in the structure, so when manufacturing a blend or alloy to recycle it, a single physical property Because it is difficult to implement, there are many restrictions on the recycling of waste plastics.

Accordingly, excellent single physical properties can be realized by using the carbon fiber composite resin according to an embodiment of the present invention as a compatibilizer in a blend or alloy of waste plastic resin.

In one embodiment, it is preferable to blend 10 to 100 parts by weight of the carbon fiber composite resin compared to 100 parts by weight of the waste plastic resin. In this case, when the amount is less than 10 parts by weight, the mixing effect is insignificant, and when it exceeds 100 parts by weight, the melting point increases and the moldability may decrease.

The present invention basically contains a thermoplastic phenoxy polymer resin with excellent adhesion and improves the moldability of the conventional difficult composite resin by compounding chopped carbon fibers with a length of 1 to 6 mm as a reinforcing material. It is possible to easily expand the use of the composite resin and provide a novel composite resin with excellent mechanical properties.

In addition to the uses of the carbon fiber composite resin according to an embodiment of the present invention described above, the uses of the present invention may be very diverse, and the use is not particularly limited.

Hereinafter, the present invention will be described in more detail through examples. The present embodiment is intended to explain the present description in more detail, and the scope of the present invention is not limited to the embodiment.

[Example]

[Preparation and Experimental Example]

1. Carbon Short Fiber

Carbon fiber has a tensile strength of 4.9 GPa, a modulus of elasticity of 230 GPa ^{, and a density of 1.82 g/cm 2} , and has a length of 1mm / 3mm / 6mm / 7mm. Prepare the powder with Prepare carbon fiber T700 products manufactured by Toray by chopping & milling them by length.

2. Phenoxy polymer resin

For the phenoxy polymer resin, a solid resin (PKFE, Inchem, Inc.) having an MI of 4 g/10min and a Mw of 60,000 g/mol was prepared.

3. Extruder

Twin screw extruder (Ba-11, Bautech), the die has an L/D (length/diameter) of 20, and uses a round die nozzle, the screw speed is 300 rpm, and the extrusion temperature is in four temperature ranges from the cylinder inside the extruder to the die. Phosphorus was set to 120 °C, 180 °C, 230 °C, and 280 °C, respectively.

4. Preparation of test specimens

In the case of the composite resin obtained in the form of pellets in Examples and Comparative Examples, all test specimens were produced by injection molding, and in the case of the composite resin obtained in the form of a sheet, the test specimens were high-temperature compressed using a hot press after fixing a release paper on both sides. After that, it was cut and manufactured.

5. Test Evaluation Method

(1) Tensile strength test method

Test Specification: ASTM D 3039

Testing machine: Universal testing machine from SHIMADZU

Load: 500 kN

Crosshead speed (test speed): 5 mm/min

(2) Flexural strength test method

Test Specification: ASTM D 790

Testing machine: Universal testing machine from SHIMADZU

Load: 300 kN

Test speed: 3 mm/min

(3) Impact strength test method

Test Specification: ASTM A370

Test equipment: SSAUL BESTECH's impact tester (BESTIPT-334CI)

[Example 1]

100 parts by weight of the solid phenoxy polymer resin (PKFE, InChem) of Formula 1 described above was put into a stirring mixer equipped with a stirrer and a thermometer, completely melted at 180° C., and then 5 parts by weight of short carbon fibers with a length of 1 mm were added to 180° C. After mixing at a rotation speed of 120 m/s for 90 minutes, it was immediately put into the extruder hopper, kneaded, cooled and pulverized into pellets to obtain a carbon fiber composite resin. Meanwhile, for injection molding after the mixing process, the temperature of the injection machine was set to about 180° C., and a specimen having a thickness of 5 mm was manufactured.

[Example 2]

A carbon fiber composite resin was prepared in the same manner as in Example 1, except that 10 parts by weight of short carbon fibers were added.

[Example 3]

A carbon fiber composite resin was prepared in the same manner as in Example 1, except that 100 parts by weight of short carbon fibers were added.

[Example 4]

A carbon fiber composite resin was prepared in the same manner as in Example 1, except that 200 parts by weight of short carbon fibers were added and the mixing temperature was raised to 200°C.

[Comparative Example 1]

A carbon fiber composite resin was prepared in the same manner as in Example 1, except that 210 parts by weight of short carbon fibers were added and the mixing temperature was raised to 250°C.

[Example 5]

A carbon fiber composite resin was prepared in the same manner as in Example 1, except that 5 parts by weight of short carbon fibers having a length of 3 mm were added.

[Example 6]

A carbon fiber composite resin was prepared in the same manner as in Example 1, except that 10 parts by weight of short carbon fibers having a length of 3 mm were added.

[Example 7]

A carbon fiber composite resin was prepared in the same manner as in Example 1, except that 100 parts by weight of short carbon fibers having a length of 3 mm were added.

[Example 8]

A carbon fiber composite resin was prepared in the same manner as in Example 1, except that 200 parts by weight of short carbon fibers having a length of 3 mm were added and the mixing temperature was raised to 200°C.

[Comparative Example 2]

A carbon fiber composite resin was prepared in the same manner as in Example 1, except that 210 parts by weight of short carbon fibers having a length of 3 mm were added and the mixing temperature was raised to 250°C.

[Example 9]

A carbon fiber composite resin was prepared in the same manner as in Example 1, except that 5 parts by weight of short carbon fibers having a length of 6 mm were added.

[Example 10]

A carbon fiber composite resin was prepared in the same manner as in Example 1, except that 10 parts by weight of short carbon fibers having a length of 6 mm were added.

[Example 11]

A carbon fiber composite resin was prepared in the same manner as in Example 1, except that 100 parts by weight of short carbon fibers having a length of 6 mm were added.

[Example 12]

A carbon fiber composite resin was prepared in the same manner as in Example 1, except that 200 parts by weight of short carbon fibers having a length of 6 mm were added and the mixing temperature was increased to 200°C.

[Comparative Example 3]

A carbon fiber composite resin was prepared in the same manner as in Example 1, except that 210 parts by weight of short carbon fibers having a length of 6 mm were added and the mixing temperature was increased to 250°C.

[Comparative Example 4]

A carbon fiber composite resin was prepared in the same manner as in Example 1, except that 5 parts by weight of short carbon fibers having a length of 7 mm were added.

[Comparative Example 5]

A carbon fiber composite resin was prepared in the same manner as in Example 1, except that 10 parts by weight of short carbon fibers having a length of 7 mm were added.

[Comparative Example 6]

A carbon fiber composite resin was prepared in the same manner as in Example 1, except that 100 parts by weight of a short carbon fiber having a length of 7 mm was added.

[Comparative Example 7]

A carbon fiber composite resin was prepared in the same manner as in Example 1, except that 200 parts by weight of short carbon fibers having a length of 7 mm were added and the mixing temperature was raised to 200°C.

[Comparative Example 8]

A carbon fiber composite resin was prepared in the same manner as in Example 1, except that 210 parts by weight of short carbon fibers having a length of 7 mm were added and the mixing temperature was raised to 250°C.

[Comparative Example 9]

A carbon fiber composite resin was prepared in the same manner as in Example 5, except that 5 parts by weight of carbon fiber powder was added instead of short carbon fibers having a length of 3 mm.

[Comparative Example 10]

A carbon fiber composite resin was prepared in the same manner as in Example 6, except that 10 parts by weight of carbon fiber powder was added instead of short carbon fibers having a length of 3 mm.

[Comparative Example 11]

A carbon fiber composite resin was prepared in the same manner as in Example 7, except that 100 parts by weight of carbon fiber powder was added instead of short carbon fibers having a length of 3 mm.

[Comparative Example 12]

A carbon fiber composite resin was prepared in the same manner as in Example 8, except that 200 parts by weight of carbon fiber powder was added instead of short carbon fibers having a length of 3 mm and the mixing temperature was raised to 200°C.

[Comparative Example 13]

A carbon fiber composite resin was prepared in the same manner as in Comparative Example 2, except that 210 parts by weight of carbon fiber powder was added instead of short carbon fibers having a length of 3 mm and the mixing temperature was raised to 250°C.

[Comparative Example 14]

A carbon fiber composite resin was prepared in the same manner as in Example 7 except that 100 parts by weight of the polypropylene resin was added instead of 100 parts by weight of the phenoxy polymer resin.

[Comparative Example 15]

A carbon fiber composite resin was prepared in the same manner as in Example 7, except that 100 parts by weight of the polyamide resin was added instead of 100 parts by weight of the phenoxy polymer resin.

[Comparative Example 16]

A specimen was prepared through injection molding by melting a pure phenoxy polymer resin (PKFE, InChem, Inc.) not containing short carbon fibers or carbon fiber powder.

molten state The tensile strength
(Mpa) flexural strength
(Mpa) impact strength
(J/cm ² ) 1 (mm) Example 1 Good 154 128 290 Example 2 Good 230 250 320 Example 3 Good 480 580 360 Example 4 Good 962 1,210 380 Comparative Example 1 Agglomeration / Non-melting non-uniform destruction non-uniform destruction non-uniform destruction 3 (mm) Example 5 Good 280 430 330 Example 6 Good 326 524 350 Example 7 Good 1,280 1,530 430 Example 8 Good 3,233 2,890 450 Comparative Example 2 Agglomeration / Non-melting non-uniform destruction non-uniform destruction non-uniform destruction 6 (mm) Example 9 Good 180 430 400 Example 10 Good 260 590 430 Example 11 Good 1,930 1,860 710 Example 12 Good 2.234 2,050 780 Comparative Example 3 Agglomeration / Non-melting non-uniform destruction non-uniform destruction non-uniform destruction 7(mm) Comparative Example 4 agglutination 150 340 450 Comparative Example 5 agglutination 186 386 480 Comparative Example 6 agglutination non-uniform destruction non-uniform destruction non-uniform destruction Comparative Example 7 agglutination non-uniform destruction non-uniform destruction non-uniform destruction Comparative Example 8 Agglomeration / Non-melting non-uniform destruction non-uniform destruction non-uniform destruction powder Comparative Example 9 Good 98 110 250 Comparative Example 10 agglutination 110 134 280 Comparative Example 11 agglutination non-uniform destruction non-uniform destruction non-uniform destruction Comparative Example 12 Agglomeration / Non-melting non-uniform destruction non-uniform destruction non-uniform destruction Comparative Example 13 Agglomeration / Non-melting non-uniform destruction non-uniform destruction non-uniform destruction 3 (mm) Comparative Example 14 Good 92 105 220 3 (mm) Comparative Example 15 Good 140 110 180 none Comparative Example 16 Good 145 116 240

<Comparison of mechanical properties by length of short carbon fibers>

A composite resin was prepared by dividing the length of the short carbon fibers into 1 mm, 3 mm, 6 mm, and 7 mm, respectively, and the mechanical properties were confirmed and shown in Table 1.

As can be seen in Table 1 above, Examples 5 to 8 in which the length of the short carbon fibers were 3 mm showed the highest tensile strength and flexural strength values, and it can be confirmed that the three-dimensional irregular isotropy was most expressed in the 3 mm section. In addition, in Comparative Examples 4 to 8, in which the short carbon fibers are 7 mm, when the input amount is small, the values of tensile strength and flexural strength can be confirmed, but when the input amount is 100 parts by weight or more (refer to Comparative Examples 6 to 8) It is difficult to calculate an accurate measurement value due to the occurrence of one fracture. In addition, it can be seen that in Comparative Examples 9 to 13 in which short carbon fibers were added as powder, non-uniform fracture occurred due to manufacturing defects of the specimen, and thus measurement was impossible.

In addition, as shown in the results of Comparative Examples 14 and 15, 100 parts by weight of the same 3 mm long carbon fiber, which is the same blending amount as the phenoxy polymer resin, was added to the polypropylene resin and the polyamide resin (nylon resin), respectively. In Comparative Examples, it can be seen that tensile strength, flexural strength and impact strength are significantly reduced than in Example 7. In addition, Comparative Example 16 using only pure phenoxy polymer resin (PKFE, InChem) also shows the same results.

As described above, when the phenoxy polymer resin according to the present invention is used together with short carbon fibers, it can be seen that the physical properties of the composite resin are remarkably improved.

<Comparison of mechanical properties by input amount of short carbon fiber>

In addition, as can be seen in Table 1 above, the amount of carbon short fibers compared to 100 parts by weight of the phenoxy polymer resin was divided into 5, 10, 100, 200, and 210 parts by weight, respectively, and as a result, in Comparative Examples in which 210 parts by weight was added, phenoxy was added. In the process of stirring and mixing with the polymer resin, agglomeration and unmelting occurred, resulting in specimen defects, and in Comparative Examples using a short carbon fiber length of 7 mm and powder, the same phenomenon was found when 100 parts by weight was added. As a result, it can be seen that the tensile strength, the flexural strength, and the impact strength increase equally in all the examples as the short carbon fiber content is increased to 200 parts by weight.

As can be seen from this, it can be seen that the mechanical properties of the carbon fiber composite resin using the phenoxy polymer resin according to an embodiment of the present invention are remarkably improved.

[Example 13]

100 parts by weight of a solid phenoxy polymer resin (PKFE, InChem) was put into a stirring mixer equipped with a stirrer and a thermometer, completely melted at 180° C., and then 200 parts by weight of a short carbon fiber having a length of 3 mm was added, and the temperature was 180° C. for 90 minutes. After mixing at a rotation speed of 120 m/s, it was immediately put into the extruder hopper, kneaded and then extruded to obtain a composite resin having a thickness of 3 mm and cooled. After that, the carbon fiber fabric (WF230N, thickness: 0.22mm) was placed on the release paper, and the obtained sheet-form composite resin was pressurized at 180° C. in an isostatic state (4 Mpa) to impregnate one side of the carbon fiber fabric to prepreg. was obtained. The thickness of the finally obtained prepreg was 5 mm.

[Example 14]

100 parts by weight of a solid phenoxy polymer resin (PKFE, InChem) was put into a stirring mixer equipped with a stirrer and a thermometer, completely melted at 180° C., and then 200 parts by weight of a short carbon fiber having a length of 3 mm was added, and the temperature was 180° C. for 90 minutes. After mixing at a rotation speed of 120 m/s, the temperature is gradually cooled to 100° C. until 5 minutes before stirring and mixing is finished, and then 3 parts by weight of an isocyanate curing agent (Aekyung Chemical, AK-75) is added and stirred for 5 minutes and mixed immediately. After input into the extruder hopper, kneading and extrusion molding to obtain a composite resin in the form of a sheet having a thickness of 3 mm, followed by cooling. After that, the carbon fiber fabric (WF230N, thickness: 0.22mm) was placed on the release paper, and the obtained sheet-form composite resin was pressurized at 180° C. in an isostatic state (4 Mpa) to impregnate one side of the carbon fiber fabric to prepreg. was obtained. The thickness of the final obtained prepreg was 5 mm.

[Example 15]

The carbon fiber prepreg impregnated with the composite resin obtained in Example 13 was placed again on the release paper, and 4,4-diaminodiphenylsulfone based on 100 parts by weight of the liquid epoxy resin composition (epoxy resin (Kukdo Chemical, YD-128)) 1 part by weight) was heated to 40° C. and flowed to obtain a prepreg by impregnating it as thinly as possible with a rubber spatula so that the carbon fiber fabric was completely wetted. Thereafter, the prepreg was cut, and the specimen was cured in an autoclave at 180° C. for 2 hours at a pressure of 0.59 MPa. The thickness of the finally obtained prepreg was 5 mm.

[Comparative Example 17]

A carbon fiber fabric (WF230N, thickness: 0.22 mm) was placed on the release paper, and a liquid epoxy resin composition (1 part by weight of 4,4-diaminodiphenylsulfone compared to 100 parts by weight of epoxy resin (Kukdo Chemical, YD-128)) was added. The prepreg was obtained by heating to 40° C. and impregnating it as thinly as possible with a rubber spatula so that the carbon fiber fabric was completely wetted. Thereafter, the prepreg was cut, and the specimen was cured in an autoclave at 180° C. for 2 hours at a pressure of 0.59 MPa. The thickness of the finally obtained prepreg was 5 mm.

molten state Tensile strength (Mpa) Flexural strength (Mpa) Impact strength (J/cm ² ) Example 13 Good 2,540 2,450 350 Example 14 Good 2,750 2,430 320 Example 15 Good 3,720 2,830 360 Comparative Example 17 Good 1,680 1,720 70

<Comparison of mechanical properties when carbon fiber reinforced plastic prepreg is applied>

As can be seen from Table 2, in Example 13, the carbon fiber composite resin according to an embodiment of the present invention was impregnated into the carbon fiber fabric to confirm the mechanical properties in the form of a conventional prepreg, and as a result, the mechanical properties were significantly increased. can see.

In addition, in Example 14, it can be seen that the tensile strength slightly increased compared to Example 13 as a result of checking the mechanical properties by adding a thermosetting agent to the carbon fiber composite resin according to an embodiment of the present invention, and in Example 15, the present invention When the thermosetting epoxy resin is impregnated again in the prepreg impregnated with the carbon fiber composite resin according to an embodiment, it can be seen that the mechanical properties are more remarkably increased.

In particular, it can be seen that the mechanical properties are improved in all examples compared to Comparative Example 17 using only the thermosetting epoxy resin, and in particular, it can be confirmed that the strength is significantly improved by nearly 5 times in the impact strength value.

It is particularly noteworthy from this that, compared to the conventional thermosetting prepreg using carbon fiber fabric (Comparative Example 17), the mechanical strength even when the carbon fiber composite resin of the present invention containing short carbon fibers is used as an intermediate substrate (Example 15). is improved, and when the short carbon fibers were used with the length of 3 mm and 6 mm, higher mechanical strength was exhibited than that of the conventional thermosetting prepreg (refer to Examples 8 and 12).

As can be seen from this, it can be seen that the mechanical properties are remarkably improved even when the carbon fiber composite resin according to an embodiment of the present invention is used alone for a prepreg or when used as an intermediate substrate of a conventional prepreg. .

[Example 16]

100 parts by weight of a solid phenoxy polymer resin (PKFE, InChem) was added to a stirring mixer equipped with a stirrer and a thermometer, completely melted at 180° C., and then 200 parts by weight of a short carbon fiber with a length of 3 mm was added, and 200° C. for 90 minutes. The mixture was mixed at a rotation speed of 120 m/s, and immediately put into the extruder hopper, kneaded, and then cooled and pulverized into pellets to obtain a composite resin (same as Example 8).

Then, 100 parts by weight of wood flour (softwood, 20 mesh, moisture content 3%), 50 parts by weight of the obtained composite resin, and 0.7 parts by weight of a lubricant (calcium stearate) were mixed, and a 40 mm twin screw extruder (L/D = 40) was used. A synthetic wood blending resin composition sample was prepared under extrusion conditions of an extrusion temperature of 170 to 190° C., a screw rotation speed of 150 rpm, and a residence time of 30 seconds. The test method of this example was performed according to the Korean Industrial Standard (KS F 3230) standard. Same as below.

[Example 17]

A synthetic wood blending resin composition sample was prepared in the same manner as in Example 16, except that 100 parts by weight of the composite resin was added.

[Example 18]

A synthetic wood blending resin composition sample was prepared in the same manner as in Example 16, except that 150 parts by weight of the composite resin was added.

[Example 19]

A synthetic wood blending resin composition sample was prepared in the same manner as in Example 16, except that 200 parts by weight of the composite resin was added.

[Example 20]

A synthetic wood blending resin composition sample was prepared in the same manner as in Example 16, except that 150 parts by weight of the composite resin and 50 parts by weight of the homo polypropylene resin were added.

[Comparative Example 18]

A synthetic wood blending resin composition sample was prepared in the same manner as in Example 16, except that 50 parts by weight of the homo polypropylene resin was added instead of the composite resin.

Synthetic wood was prepared using the synthetic wood blending resin composition prepared in Examples 16 to 20 and Comparative Example 18, and then physical properties were evaluated through the following experimental examples, and the results are shown in Table 3 below.

[Experimental example]

1. Measurement of maximum bending load

For the maximum bending load, the radius and test speed of the pressure bar and support are determined according to KS M ISO 178, and the maximum bending load is measured by mounting the test piece. A total of three tests were performed and the average value recorded.

2. Impact strength measurement

The impact strength test is performed using a test piece without a notch according to KS M ISO 179-1. The striking surface is the exposed surface during product construction, and the average value of the five specimens is calculated according to Equation 1 below, and the impact strength acU is calculated and expressed in units of kJ/m2.

(Equation 1)

acU =

Ec: corrected absorbed energy (J) by fracture of the specimen

h: thickness of test piece (mm)

b: width of the test piece (mm)

3. Measurement of Length Linear Thermal Expansion Coefficient

The length linear thermal expansion coefficient is measured in accordance with KS M 3060 or KS M ISO 11359-2 in the temperature range of -30°C to 60°C and calculated by Equation 2 below.

(Equation 2)

Length linear thermal expansion coefficient (1/℃) = (L2-L1) / L0 (T2-T1) = △L/L0 △T

L2, L1: length of each specimen at temperature T2, T1

L0: length of test piece at room temperature

(Room temperature corresponds to the conditions of temperature (23 ± 2) ℃ and humidity (50 ± 5) %)

4. Distortion measurement

In order to test the torsion property, it was performed according to the Korean Industrial Standard (KS F 3230) standard.

5. Check flame retardancy

In order to test the flame retardancy (carbonization length), it was performed according to the Korean Industrial Standard (KS F 3230) standard.

Test Items Example
16 Example
17 Example
18 Example
19 Example
20 comparative example
18 Applicable standard Maximum bending load (N) 3,820 4,310 4,450 4,860 4,320 3,340 KS F 3230 Impact strength (kJ/㎡) 3.9 4.5 4.7 4.7 5.3 3.8 KS F 3230 Twisting (%) 0.2 0.1 0.2 0.2 0.2 0.3 KS F 3230 Length linear coefficient of thermal expansion
(1/℃) 2.4x10 ^-5 2.4x10 ^-5 2.3x10 ^-5 2.1x10 ^-5 2.8x10 ^-5 4.8x10 ^-5 KS F 3230 Flame retardant (carbonized length) 10 10 8 8 11 28 KS F 3230

As can be seen from Table 3, a carbon fiber composite resin was mixed with wood flour according to Examples 16 to 20 of the present invention to produce synthetic wood, and as a result of evaluation according to the KS standard, a comparison using a conventional polypropylene resin It can be seen that improved physical properties compared to Example 18.

In particular, the thermal expansion coefficient value shows a tendency to decrease as the blending amount of the carbon fiber composite resin increases, as well as a significantly lower value compared to the comparative example, thereby confirming that the technical effect of the carbon fiber composite of the present invention is clear. In general, in the case of a conventional wood-plastic composite, it is often exposed to the outside, so the shrinkage and expansion due to heat is severe, and distortion occurs after construction, so that re-construction is often required. In the case of the present invention, there is an advantage that can be minimized.

In addition, as can be seen from Table 3, the flame retardancy also showed a significantly higher value than that of the conventional comparative example. Of course, in the case of the comparative example, there is a reason that a separate flame retardant was not added. It can be seen that it shows excellent flame retardancy.

In addition, as can be seen in Example 20, as a result of using the composite resin of the present invention and the conventional polypropylene resin mixed, the overall physical property value increased compared to the comparative example, and, in particular, the highest value was shown in the impact strength value.

As can be seen from this, it can be seen that the mechanical properties are significantly improved even when the carbon fiber composite resin according to an embodiment of the present invention is used alone for synthetic wood or mixed with a conventional homo polypropylene resin. can

[Example 21]

100 parts by weight of a solid phenoxy polymer resin (PKFE, InChem) was put into a stirring mixer equipped with a stirrer and a thermometer, completely melted at 200° C., and then 200 parts by weight of short carbon fibers with a length of 6 mm were added to 180° C. for 90 minutes. The mixture was mixed at a rotation speed of 120 m/s, and immediately put into an extruder hopper, kneaded, cooled, and then pulverized into pellets to obtain a composite resin (same as Example 12).

Then, a bracket resin composition sample was prepared under extrusion conditions of an extrusion temperature of 180 to 210° C., a screw rotation speed of 150 rpm and a residence time of 30 seconds using a 40 mm twin-screw extruder (L/D=40).

[Example 22]

Bracket resin in the same manner as in Example 21, except that 100 parts by weight of a polyamide resin (PA 12, product name: L1940, EVONIK company, viscosity: 177ml/g) and 10 parts by weight of the composite resin obtained in Example 21 were mixed. Composition samples were prepared.

[Example 23]

Bracket resin in the same manner as in Example 21, except that 100 parts by weight of polyamide resin (PA 12, product name: L1940, EVONIK company, viscosity: 177 ml/g) and 50 parts by weight of the composite resin obtained in Example 21 were mixed. Composition samples were prepared.

[Example 24]

Bracket resin in the same manner as in Example 21, except that 100 parts by weight of a polyamide resin (PA 12, product name: L1940, EVONIK company, viscosity: 177 ml/g) and 100 parts by weight of the composite resin obtained in Example 21 were mixed. Composition samples were prepared.

[Comparative Example 19]

A bracket resin composition sample was prepared in the same manner as in Example 21, except that a polyamide resin (PA 12, product name: L1940, EVONIK, viscosity: 177 ml/g) was used instead of the composite resin obtained in Example 21. prepared.

For the bracket resin compositions prepared in Examples 21 to 24 and Comparative Example 19, physical properties were evaluated through the following experimental examples, and the results are shown in Table 5 below.

[Experimental example]

1. Adhesive strength and impact strength measurement

When measuring the adhesive strength, a polyurethane adhesive from Fuller's 9777 was used, and for the adhesive strength test, the Dupont Drop Method was used, and the impact strength was in accordance with the KS F3230 standard.

The bonding strength of the double-sided product in the adhesive-layer direction was measured using the DuPont drop test (Lab-Q E602, manufactured by CKSI) of Table 4 below. For this test, a substrate made of a 40mm x 40mm rectangular PA bracket material was used, and a 5mm thick, 20mm x 20mm glass was coated with the prepared bracket resin composition to a width of 1mm and bonded. The bracket substrate has a rectangular hole of 10 mm x 10 mm. A load weight was used to drop the glass through the hole in the bracket, and a force was applied on the joint joined in this way, the adhesive strength was measured in mJ, and the impact strength was measured in the unit of kJ/m2. At this time, the test was performed at 23° C. and 50% relative humidity.

Model Lab-Q E602 Drop Height (Test Height) Max. 1000 mm Fall Interval 50mm Falling Load 2000 g Punch Radius 1/8" R Concave Radius 1/2" R, Plate Dimensions 550x350x1500 mm (WxDxH) Test standard (Ref. standard) JIS K 5400, ASTM D 2794 (paper, film)

2. Measurement of Length Linear Thermal Expansion Coefficient

The length linear thermal expansion coefficient is measured in accordance with KS M 3060 or KS M ISO 11359-2, and is tested in the temperature range of -30°C to 60°C and calculated by Equation 2 below.

(Equation 2)

Length linear thermal expansion coefficient (1/℃) = (L2-L1) / L0 (T2-T1) = △L/L0 △T

L2, L1: length of each specimen at temperature T2, T1

L0: length of test piece at room temperature

(Room temperature corresponds to the conditions of temperature (23 ± 2) ℃ and humidity (50 ± 5) %)

Test Items Example
21 Example
22 Example
23 Example
24 comparative example
19 Applicable standard Adhesive strength (mJ) 1,850 120 670 920 85 Dupont Drop Impact strength (kJ/㎡) 7.9 4.8 5.5 7.2 4.2 KS F 3230 Length linear thermal expansion coefficient (1/℃) 1.2x10 ^-5 4.5x10 ^-5 2.3x10 ^-5 1.8x10 ^-5 4.8x10 ^-5 KS F 3230

As can be seen in Table 5, when the bracket is manufactured using the composite resin alone according to the embodiment of the present invention, it can be seen that the adhesive strength is remarkably increased compared to the comparative example prepared with the polyamide resin alone, In addition, it can be seen that the adhesive strength significantly increases as the compounding amount of the composite resin increases even when mixed with the polyamide resin.

In particular, considering that the bracket is sensitive to deformation due to heat of the electronic device and is easy to be exposed to external environments such as impact in the case of a portable mobile device, comparing the values of the examples of the impact strength and the thermal expansion coefficient with those of the comparative example It can be confirmed that the composite resin of the present invention has excellent physical properties.

Although the preferred embodiment of the present invention has been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements by those skilled in the art using the basic concept of the present invention as defined in the following claims are also provided. is within the scope of the

1: Phenoxy polymer resin
2: carbon short fiber
2-1: 1mm long carbon short fiber
2-3: 3mm long carbon short fiber
2-6: 6mm long carbon short fiber
3: Cellulose, the main component of wood flour
4: Composite wood
5: carbon fiber
10: liquid crystal glass
20: the bracket of the smartphone
100: resin composition for mobile display bracket

Claims (9)

Including carbon fiber composite resin and polyamide resin,
The carbon fiber composite resin includes a phenoxy polymer resin according to Formula 1 and short carbon fibers,
(Formula 1)

Here, n is an integer of 1 to 100, which is prepared from the carbon fiber composite resin composition, a resin composition for a mobile display bracket comprising a carbon fiber composite resin. According to claim 1,
The phenoxy polymer resin has a weight average molecular weight of 10,000 to 70,000 g/mol, a resin composition for a mobile display bracket comprising a carbon fiber composite resin. According to claim 1,
The short carbon fiber has a length of 1 to 6mm, a resin composition for a mobile display bracket comprising a carbon fiber composite resin. According to claim 1,
A resin composition for a mobile display bracket comprising a carbon fiber composite resin comprising 10 to 200 parts by weight of the short carbon fibers relative to 100 parts by weight of the phenoxy polymer resin. According to claim 1,
The carbon fiber composite resin is obtained in the form of pellets or sheets or films through extrusion molding, a resin composition for a mobile display bracket comprising a carbon fiber composite resin. delete According to claim 1,
The resin composition for the bracket comprises 10 to 100 parts by weight of the carbon fiber composite resin relative to 100 parts by weight of the polyamide resin, the resin composition for a mobile display bracket comprising a carbon fiber composite resin. According to claim 1,
The carbon fiber composite resin composition further comprises at least one curing agent selected from urea, isocyanate, and melamine, a resin composition for a mobile display bracket comprising a carbon fiber composite resin. A mobile display device manufactured using the resin composition for a mobile display device bracket comprising the carbon fiber composite resin according to any one of claims 1 to 5, 7 and 8.

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