KR102253103B1 - Fiber reinforced composite material and method of manufacturing the same - Google Patents

Abstract

A thermoplastic resin composition comprising a mixed resin comprising a polyethylene terephthalate copolymer and a polyamide and a compatibilizer; And it provides a fiber-reinforced composite including fibers.

Description

Fiber reinforced composite and its manufacturing method {FIBER REINFORCED COMPOSITE MATERIAL AND METHOD OF MANUFACTURING THE SAME}

It relates to a fiber-reinforced composite and a method of manufacturing the same.

A composite material used for various purposes is made by combining two or more materials, and can generally be prepared by mixing a polymer resin with glass fiber or carbon fiber as a reinforcing material. In addition, there are thermoplastic resin compositions containing fibrous fillers and silicone rubber as essential components as composite materials, and moldings manufactured using the same. Such composite materials can be used in industrial fields requiring high strength and rigidity. Accordingly, there is a need for research to have excellent strength and stiffness along with excellent flexibility, and at the same time secure economical efficiency.

One embodiment of the present invention provides a fiber-reinforced composite material that can economically secure excellent impact strength, flexural strength, flexural elongation and tensile strength.

Another embodiment of the present invention provides a method of manufacturing the fiber-reinforced composite.

In one embodiment of the present invention, a thermoplastic resin composition comprising a mixed resin including a polyethylene terephthalate copolymer and a polyamide and a compatibilizer; And it provides a fiber-reinforced composite including fibers.

In another embodiment of the present invention, preparing a thermoplastic resin composition by mixing a mixed resin containing a polyethylene terephthalate copolymer and a polyamide and a compatibilizer; And impregnating fibers with the thermoplastic resin composition.

The fiber-reinforced composite material can economically secure excellent impact strength, flexural strength, flexural elongation, tensile elongation and tensile strength, and can be widely used for various purposes.

Advantages and features of the present invention, and a method of achieving them will become apparent with reference to the following embodiments. However, the present invention is not limited to the embodiments disclosed below, but will be implemented in a variety of different forms, only the present embodiments are intended to complete the disclosure of the present invention, and common knowledge in the technical field to which the present invention pertains. It is provided to completely inform the scope of the invention to those who have, and the invention is only defined by the scope of the claims.

In one embodiment of the present invention, a thermoplastic resin composition comprising a mixed resin comprising a polyethylene terephthalate copolymer and a polyamide (polyamide) and a compatibilizer; And it provides a fiber-reinforced composite including fibers. The fiber-reinforced composite material includes a mixed resin including a polyethylene terephthalate copolymer and polyamide, and economically secures excellent impact strength, flexural strength, flexural elongation, tensile elongation and tensile strength.

Polyamide has excellent mechanical properties, but the price of polyamide resin is high, and its crystallinity is high, so it is brittle and moldability is poor. Accordingly, it may be difficult to use polyamide as a resin for fiber-reinforced composites.

In addition, polyethylene terephthalate copolymer is economical compared to other resins compared to other resins, for example, polyethylene terephthalate copolymer is economical compared to resins such as polyamide and polyetheretherketone (PEEK). Although it can impart excellent weather resistance, there is a problem that mechanical properties are relatively poor.

The fiber-reinforced composite material includes a mixed resin including a polyethylene terephthalate copolymer and a polyamide in a thermoplastic resin composition. Specifically, the polyethylene terephthalate copolymer may be polyethylene terephthalate glycol (PETG) as a 100% amorphous amorphous polyethylene terephthalate copolymer. The polyethylene terephthalate copolymer may easily secure compatibility with polyamide, and may impart ductility by lowering the crystallinity of the mixed resin containing the polyamide. Accordingly, the fiber-reinforced composite material including the mixture can economically secure excellent impact strength, flexural strength, flexural elongation and tensile strength.

The fiber-reinforced composite may include from about 35% to about 70% by weight of the mixed resin, for example, from about 35% to about 45% by weight. When the mixed resin is included in an amount within the above range, fibers may be evenly impregnated in the manufacturing process, and the fiber-reinforced composite may secure a support performance of a certain level or higher.

The mixed resin may include a polyethylene terephthalate copolymer to a polyamide in a weight ratio of about 50:50 to about 30:70. Specifically, when the weight ratio of the polyethylene terephthalate copolymer exceeds the above range, the specific gravity increases and mechanical properties may decrease. In addition, when the weight ratio of the polyamide exceeds the above range, there may be a problem in that the cost increases, brittleness is expressed, and moldability is deteriorated.

The fiber-reinforced composite material can economically secure excellent impact strength, flexural strength, flexural elongation, tensile elongation and tensile strength by including a compatibilizer together with the polyethylene terephthalate copolymer and the mixed resin containing the polyamide. have.

When the fiber-reinforced composite material includes a polyethylene terephthalate copolymer and a polyamide heterogeneous resin together, the desired physical properties cannot be obtained due to low compatibility between the heterogeneous resins. In particular, in the case of a polyethylene terephthalate copolymer and a polyamide heterogeneous resin, the properties of each resin may be canceled due to an ester-amide exchange reaction between the polyethylene terephthalate copolymer and the polyamide, and thus physical properties may be further deteriorated.

The fiber-reinforced composite may contain a compatibilizer together with the polyethylene terephthalate copolymer and the mixed resin containing the polyamide to suppress the ester-amide exchange reaction and increase compatibility between the resins.

The fiber-reinforced composite may include a compatibilizer having two or more reactive functional groups together with the mixed resin. The compatibilizer has two or more reactive functional groups, and can be easily located at the interface between the polyethylene terephthalate copolymer and the polyamide. Therefore, the compatibilizer can improve the compatibility between the two resins even with a small amount. In addition, the compatibilizer may be located at an interface between the polyethylene terephthalate copolymer and the polyamide to efficiently induce a chemical reaction. Accordingly, it is possible to suppress an ester-amide exchange reaction between the two resins, improve interfacial adhesion between the two resins, and increase compatibility.

Specifically, the reactive functional group is one selected from the group consisting of anhydride group, epoxide group, oxazoline group, isocyanate group, carbamate group, and combinations thereof. I can. The compatibilizer having two or more reactive functional groups may extend the molecular chain through a chemical reaction at the interface between the polyethylene terephthalate copolymer and the polyamide. And, it is possible to induce desired physical properties by controlling the network structure in the thermoplastic resin composition containing the same.

The fiber-reinforced composite material includes the reactive functional group, and improves interfacial adhesion between the two resins and increases compatibility, and thus may have significantly improved mechanical properties.

The weight average molecular weight of the compatibilizer may be about 218 to about 6,800. The compatibilizer has a weight average molecular weight in the range and the number of functional groups in the range, and accordingly, the reaction temperature and reaction time can be adjusted. In addition, the compatibilizer may have a weight average molecular weight in the above range, thereby affecting the three-dimensional structure between the two resins.

The fiber-reinforced composite may include about 0.5 parts by weight to about 2 parts by weight of the compatibilizer based on 100 parts by weight of the mixed resin. Specifically, when the content of the compatibilizer is less than the above range, phase separation may occur between the polyethylene terephthalate copolymer and the polyamide, resulting in a problem such as deterioration of physical properties. In addition, when the content of the compatibilizer exceeds the above range, there may be a problem in that fairness is deteriorated due to high viscosity and brittleness is greatly expressed, and thus it is easily broken.

The fiber-reinforced composite material includes a thermoplastic resin composition including the polyethylene terephthalate copolymer and a mixed resin including the polyamide and the compatibilizer, and the glass transition temperature of the thermoplastic resin composition is about 80° C. to about 105° C. Can be

The thermoplastic resin composition may have a single glass transition temperature within the above range since the compatibility of the polyethylene terephthalate copolymer and the polyamide is remarkably improved by the compatibilizer. The fiber-reinforced composite material formed from the thermoplastic resin composition having a single glass transition temperature may have significantly improved mechanical properties.

Since the thermoplastic resin composition has a glass transition temperature in the above range, melting of the resin and impregnation of fibers may be facilitated in the manufacturing process. In addition, the fiber-reinforced composite material including the same can easily secure a support performance of a certain level or more, and can further improve the excellent mechanical properties of the polyamide, while supplementing the brittleness of the polyamide.

The fiber-reinforced composite material includes fibers, and may increase the strength and stiffness of the fiber-reinforced composite material. And, unlike when each of the polyamide and polyethylene terephthalate copolymer is used alone, the fiber is used together with the polyamide and polyethylene terephthalate copolymer contained in the fiber-reinforced composite to further increase mechanical strength and rigidity, It can have structural stability. Specifically, the fiber may include one selected from the group consisting of glass fiber, carbon fiber, aramid fiber, and combinations thereof.

The fiber-reinforced composite material may include about 40 parts by weight to about 70 parts by weight of the fiber based on 100 parts by weight of the fiber-reinforced composite material. When the fibers are included in less than the above range, it is difficult to secure the required strength and rigidity of the fiber-reinforced composite. And, when the content of the fiber exceeds the above range, impregnation of the thermoplastic resin composition as the base material is incomplete, resulting in a bursting phenomenon of the fiber due to the external environment, resulting in a decrease in surface quality, and mechanical properties such as impact strength significantly decrease. There may be a problem.

The fiber may have an average diameter of about 15 μm to about 20 μm in cross section, and may be, for example, about 16 μm to about 19 μm. If the cross section of the fiber has an average diameter of less than about 15 μm, there is a risk that the strength of the fiber-reinforced composite material is significantly reduced, and when the fiber has an average diameter of more than about 20 μm, the interfacial adhesion with the mixed resin decreases. Can be.

The fibers may be included in the form of continuous fibers.

In this case, the continuous fiber means that it exists in a continuous form without being broken inside, depending on the final size of the composite sheet. For example, like continuous fibers in a UD sheet (unidirection sheet), the continuous fibers can be produced in a continuous process, and by continuously supplying the continuous fibers to this continuous process, a composite sheet including continuous fibers can be manufactured. I can. Accordingly, the fiber-reinforced composite may be manufactured into a product having a specific shape, such as a sheet, and in such a product, the continuous fibers have a length of a specific range depending on the shape of the product. However, since the length of this specific range can be arbitrarily adjusted in the manufacturing process in which continuous fibers are continuously supplied, the continuous fibers should be viewed as having'continuity', and most of the continuous fibers such as UD sheets or continuous fibers in fabrics In case, it does not break inside the product and has continuity.

In one embodiment, the composite sheet may include continuous fibers such that the continuous fibers have a single orientation, such as a UD sheet.

Since the continuous fiber has a single orientation in the composite sheet, it may be advantageous in securing excellent strength and stiffness.

Specifically, the fact that the continuous fiber has a single orientation means that when one specific fiber strand is determined among the continuous fibers in the mixed resin, the angle formed by the specific continuous fiber with any other continuous fiber is about 10° or less, specifically about It should be understood that this includes cases of 5° or less, and includes not only completely parallel states with each other, but also non-parallel cases with a degree of error that is difficult to discern when observed with the naked eye.

The composite sheet may include continuous fibers other than long fibers or short fibers, and thus there is no problem of dispersibility of fibers, and may include fibers of a high content. Accordingly, the fiber-reinforced composite material manufactured from the composite sheet may have improved mechanical properties such as excellent surface quality, evenly realizing physical properties, and high strength properties. Typically, short fibers may mean fibers of about 1 mm or less, and long fibers may mean fibers of about 50 mm or less. When using such short fibers or long fibers, there is a problem of dispersibility in the composition, and the fibers cannot be included in a high content. In addition, there is a problem that the surface quality of the composite material is deteriorated and physical properties such as mechanical strength are deteriorated.

As such, the composite sheet may impart excellent strength and rigidity by including fibers in the form of continuous fibers.

The fiber-reinforced composite may further include one additive selected from the group consisting of antioxidants, heat stabilizers, processing aids, dispersants, pigments, and combinations thereof. For example, the additive may be included in about 1% by weight to about 10% by weight of the fiber-reinforced composite material, for example, about 0.1% by weight to about 3% by weight of a heat stabilizer, specifically, about 0.3% by weight to about It may contain 0.5% by weight.

Izod impact strength of the fiber-reinforced composite may be about 3,000J/m to about 3,800J/m. The'Izod impact strength' indicates the resistance that an arbitrary object withstands an instantaneous concentrated external force, and can be measured by the Izod impact measurement method according to ASTM D256. By maintaining the Izod impact strength in the above range, the fiber-reinforced composite material can be used in various applications where high strength and high rigidity are required, and excellent impact resistance can be secured.

Specifically, the fiber-reinforced composite may have a flexural strength of about 700 MPa to about 900 MPa. The flexural strength was measured according to ASTM D790.

The'bending strength' is a measurement of the maximum stress when the fiber-reinforced composite material is bent, and refers to the degree of resistance of the fiber-reinforced composite material to a force applied in the bending direction before being destroyed. For example, stress and distortion can be measured by pressing the center portion of a long rectangular specimen by applying a load, and can be measured by a method for measuring flexural properties according to the ASTM D790 test method.

The fiber-reinforced composite can be used in various applications requiring high strength and high rigidity by maintaining the flexural strength within the above range, and excellent weight reduction effect can be achieved by securing higher specific strength and specific rigidity than metal.

The fiber-reinforced composite may have a flexural elongation of about 1.5% to about 3%. The flexural elongation was measured according to ASTM D790. The fiber-reinforced composite has a flexural elongation within the above range, and can simultaneously impart mechanical properties such as excellent flexural strength, tensile strength, and Izod impact strength. In addition, the fiber-reinforced composite material having a flexural elongation in the above range can resist external forces, and thus can be used in products requiring high strength and high rigidity. For example, the fiber-reinforced composite may be used for interior and exterior materials for automobiles.

Another embodiment of the present invention is to prepare a thermoplastic resin composition by mixing a mixed resin containing a polyethylene terephthalate copolymer (polyethyleneterephthalate) and polyamide (polyamide) and a compatibilizer; And impregnating fibers with the thermoplastic resin composition.

Through the manufacturing method of the fiber-reinforced composite material, it is possible to manufacture a fiber-reinforced composite material that can economically secure excellent impact strength, flexural strength, flexural elongation and tensile strength.

The manufacturing method of the fiber-reinforced composite material includes preparing a thermoplastic resin composition by mixing a mixed resin including polyethyleneterephthalate and polyamide and a compatibilizer. Specifically, the step of preparing the thermoplastic resin composition may be performed at 240°C to 280°C.

Specifically, when the thermoplastic resin composition is manufactured at less than about 240° C., the thermoplastic resin composition may not secure an appropriate viscosity, and thus impregnation property may be deteriorated and processability may be deteriorated in a subsequent process. In addition, when the thermoplastic resin composition is manufactured at more than about 280°C, there may be a concern that physical properties of the composite may be damaged due to thermal decomposition of the resin, or foreign matter may be generated due to carbonization of the resin.

The fiber-reinforced composite manufactured through the fiber-reinforced composite manufacturing method includes a thermoplastic resin composition including a mixed resin including polyethyleneterephthalate and polyamide and a compatibilizer, thereby providing excellent impact strength and flexural strength. Strength, flexural elongation and tensile strength can be economically secured.

Hereinafter, specific embodiments of the present invention are presented. However, the examples described below are only for illustrating or explaining the present invention in detail, and the present invention is not limited thereto.

<Examples and Comparative Examples>

Example 1

As shown in Table 1 below, about 39.08% by weight of a mixed resin obtained by mixing polyethylene terephthalate glycol (PETG) and polyamide in a weight ratio of 50:50; About 1.02 parts by weight of bisphenol A diglycidyl ether based on 100 parts by weight of the mixed resin; Primary antioxidant ADK STAB AO-60 and secondary antioxidant ADK STAB 211; And PA520 (manufacturer: LG Chem) processing aids were mixed, and a thermoplastic resin composition was prepared at 280°C.

The thermoplastic resin composition was impregnated into glass fibers to prepare a fiber-reinforced composite. At this time, the glass fiber was used in an amount of 60 parts by weight based on 100 parts by weight of the fiber-reinforced composite.

Example 2

A fiber-reinforced composite was prepared in the same manner as in Example 1, except that polyethylene terephthalate glycol (PETG) and polyamide were mixed in a weight ratio of 30:70.

Comparative Example 1

A fiber-reinforced composite was prepared in the same manner as in Example 1, except that a compatibilizer was not used.

Comparative Example 2

A fiber-reinforced composite was prepared in the same manner as in Example 1, except that the polyethylene terephthalate copolymer was not included.

<Evaluation>

Experimental Example 1: Glass transition temperature (℃)

Using a differential scanning calorimetry (DSC) for the mixed resins of Examples and Comparative Examples, according to a general procedure for measuring the glass transition temperature, the glass transition temperature (Tg) of each mixed resin was measured, and The results are shown in Table 2 below.

Experimental Example 2: Izod impact strength (J/m)

For the specimens of the Examples and Comparative Examples, according to ASTM D256, the Izod impact strength was measured at room temperature at 23°C using an Izod impact tester, and the results are shown in Table 2 below. The hammer head of the Izod impact tester was 22.6J, and the test was conducted after making a notch of 1±0.05mm in the center to induce smooth fracture of the specimen.

Experimental Example 3: Flexural Strength (MPa) and Flexural Elongation (%)

The specimens of the Examples and Comparative Examples were measured for flexural strength at room temperature of 23° C. according to ASTM D790, and the results are shown in Table 2 below. Flexural strength and flexural elongation were measured using Instron's Universal Testing Machine, and the span distance of the specimen was set to 16 times the thickness and the deformation rate to 2 mm/min.

Experimental Example 4: Tensile strength (MPa) and tensile elongation (%)

Specimens of Examples and Comparative Examples were prepared according to ASTM D3039, and protective tabs were attached to both ends in order to cause fracture at the center of the composite material. Like the flexural strength, tensile strength and tensile elongation were measured at a tensile speed of 5mm/min using Instron's Universal Testing Machine, and the results are shown in Table 2 below.

Ingredient (% by weight) Example 1 Example 2 Comparative Example 1 Comparative Example 2 Suzy Polyamide 19.54 27.36 19.74 39.08 PETG 19.54 11.72 19.74 0 Primary antioxidant 0.04 0.04 0.04 0.04 Secondary antioxidant 0.08 0.08 0.08 0.08 Compatibilizer 0.40 0.40 - 0.40 Fiberglass 60 60 60 60 Processing aid 0.40 0.40 0.4 0.40

Example 1 Example 2 Comparative Example 1 Comparative Example 2 Glass transition temperature (℃) 86 88 83, 89 90 Izod impact strength (J/m) 3,394 3,317 2,876 3,249 Flexural strength (MPa) 761 779 540 808 Flexural elongation (%) 2.08 2.10 1.64 2.06 Tensile strength (MPa) 763 782 676 804 Tensile elongation (%) 2.45 2.38 2.01 2.32

As shown in Table 2, in the case of Comparative Example 1 containing only a mixed resin containing a polyethylene terephthalate copolymer and a polyamide without a compatibilizer, the mechanical properties were significantly inferior compared to Comparative Example 2 containing only polyamide. I can see that. On the other hand, it can be seen that Example 1 exhibits mechanical properties similar to or better than polyamide while mixing a polyethylene terephthalate copolymer which is about 5 times more economical than polyamide. That is, the fiber-reinforced composite of Example 1 may have economically excellent impact strength, flexural strength, flexural elongation, tensile elongation, and tensile strength.

Claims (16)

A thermoplastic resin composition comprising a mixed resin comprising 100% amorphous polyethylene terephthalate glycol (PETG) and polyamide and a compatibilizer; And fibers,
The fiber contains 60 parts by weight to 70 parts by weight based on 100 parts by weight of the fiber-reinforced composite,
The fiber has an average diameter of 16 μm to 19 μm in cross section
Fiber-reinforced composite.
The method of claim 1,
Comprising 35% to 70% by weight of the mixed resin
Fiber-reinforced composite.
The method of claim 1,
The weight ratio of the polyethylene terephthalate glycol (PETG) to the polyamide is 50: 50 to 30: 70
Fiber-reinforced composite.
The method of claim 1,
The glass transition temperature of the thermoplastic resin composition is 80 ℃ to 105 ℃
Fiber-reinforced composite.
The method of claim 1,
The fiber comprises one selected from the group consisting of glass fiber, carbon fiber, aramid fiber, and combinations thereof
Fiber-reinforced composite.
delete delete The method of claim 1,
The compatibilizer is a compound having two or more reactive functional groups
Fiber-reinforced composite.
The method of claim 8,
The reactive functional group is one selected from the group consisting of anhydride group, epoxide group, oxazoline group, isocyanate group, carbamate group, and combinations thereof.
Fiber-reinforced composite.
The method of claim 1,
Fiber-reinforced composite comprising 0.5 parts by weight to 2 parts by weight of the compatibilizer based on 100 parts by weight of the mixed resin.
delete The method of claim 1,
Izod impact strength of 3,000 J/m to 3,800 J/m
Fiber-reinforced composite.
The method of claim 1,
Flexural strength of 700 MPa to 900 MPa
Fiber-reinforced composite.
The method of claim 1,
Flexural elongation of 1.5% to 3%
Fiber-reinforced composite.
Preparing a thermoplastic resin composition by mixing a mixed resin containing 100% amorphous polyethylene terephthalate glycol (PETG) and polyamide and a compatibilizer; And
Including; impregnating fibers with the thermoplastic resin composition,
The fiber contains 60 parts by weight to 70 parts by weight based on 100 parts by weight of the fiber-reinforced composite,
The fiber has an average diameter of 16 μm to 19 μm in cross section
Fiber-reinforced composite manufacturing method.
The method of claim 15,
The step of preparing the thermoplastic resin composition is performed at 240 ℃ to 280 ℃
Fiber-reinforced composite manufacturing method.