KR20200066423A - Long fiber reinforced composite and molded article formed therefrom - Google Patents

Abstract

Disclosed are a long fiber-reinforced composite having excellent impregnation properties and a molded article formed therefrom. According to the present invention, the long fiber-reinforced composite is formed by impregnating long fiber with a polyolefin-based resin composition, wherein a surface of the long fiber is processed by 0.1 to 1 weight percent of an epoxy resin and the polyolefin-based resin composition comprises: an ethylene-propylene copolymer with a melting index of 500 to 2,000 g/10 min (230°C, 2.16 kg); a second propylene with an Izod impact strength of 20 to 50 J/m; and an impact resistant agent having a maleic functional group.

Description

Long fiber reinforced composite and molded article formed therefrom

It relates to a long fiber-reinforced composite material and a molded article formed therefrom.

Throughout the industry, high fuel efficiency and high efficiency have become top concerns in the 21st century. This is usually a problem that can be solved mechanically, but it is possible to maximize fuel efficiency through weight reduction using lightweight materials and plastics, and improve fuel efficiency due to weight reduction.

As the demand for polymer materials is gradually becoming functional, performance, and diversified, a small number of industries require even parts that can replace metal, and the recycling stage of the final product while maintaining the original performance of uni-materials, that is, products Until now, it is demanding the material considered. Therefore, research into long fiber-reinforced composite materials, which are high-impact and high-strength composite materials that exhibit performance that cannot be achieved with a single material, has been actively conducted.

Normally, long fiber-reinforced composite materials are manufactured by pultrusion, and the impregnation and impregnation content of the resin with respect to the fibers greatly affect the properties of the final product. Particularly, the lack of impregnation uniformity of the resin and the residuals such as voids between non-impregnated fibers may act as a cause of defects in mechanical properties in the final product, and this effect increases the number and content of supplied fibers or continuously mass-produces them. In order to increase the total discharge amount, it becomes more severe and becomes more remarkable as the final product becomes larger. Therefore, when the reinforcing fiber is impregnated into the resin, it is important to control the resin so that the resin is well dispersed and permeates all parts of the fiber and uniform impregnation to the inside of the fiber is achieved. to be.

On the other hand, polypropylene not only has a high chemical stability, but also has excellent corrosion resistance, and is used as a material for various parts throughout the industry as a lightweight material. However, in order to use polypropylene as a material of the long fiber-reinforced composite material, there is a problem in that impregnation property is poor because the interface bonding force between the polypropylene and the long fiber is weak.

An object of the present invention is to provide a long fiber-reinforced composite material and molded article having excellent impregnation properties.

Another object of the present invention is to provide a long fiber-reinforced composite material and a molded article having excellent impact characteristics and bending characteristics.

1. According to one aspect, the polyolefin-based resin composition is impregnated into long fibers treated with an epoxy-based resin of 0.1 to less than 1% by weight,

The polyolefin-based resin composition

Ethylene-propylene copolymer containing 10 to 15% by weight of ethylene,

First polypropylene having a melt index of 500 to 2000 g/10min (230°C, 2.16 kg),

A second polypropylene having an Izod impact strength of 20 to 50 J/m, and

A long fiber reinforced composite material is provided, comprising an impact modifier having a maleic acid functional group.

2. In the above 1, the second polypropylene may have a melt index of 1 to 500 g/10min (230°C, 2.16 kg).

3. In the above 1 or 2, the impact modifier may include a polyolefin elastomer grafted with maleic anhydride.

4. In any one of 1 to 3 above, the long fiber may include carbon fiber.

5. In any one of 1 to 4, the long fiber-reinforced composite material is 10 to 60 parts by weight of the ethylene-propylene copolymer,

10 to 90 parts by weight of the first polypropylene,

10 to 60 parts by weight of the second polypropylene,

1 to 10 parts by weight of the impact modifier, and

The long fiber may include 10 to 35 parts by weight.

6. In any one of 1 to 5, the long fiber-reinforced composite material may further include 0.1 to 10 parts by weight of modified polypropylene.

7. In the above 5, the modified polypropylene may include maleic anhydride grafted polypropylene.

8. In any one of 1 to 7, the melt index of the polyolefin-based resin composition may be 100 to 300 g/10min (230°C, 2.16 kg).

9. According to another aspect, a molded article formed from the long fiber-reinforced composite material of any one of 1 to 8 is provided.

10. In the above 9, the molded article may include building parts, aircraft parts, or vehicle parts.

The present invention has an effect of providing a long fiber-reinforced composite material and a molded article having excellent impregnation properties and improved impact properties and flexural properties.

Hereinafter, the present invention will be described in more detail.

In describing the present invention, when it is determined that detailed descriptions of related known technologies may unnecessarily obscure the subject matter of the present invention, detailed descriptions thereof will be omitted.

When'include','have','consist of', etc. mentioned in the specification are used, other parts may be added unless'~man' is used. When a component is expressed as a singular number, the plural number is included unless otherwise specified.

In addition, in analyzing the components, it is interpreted as including an error range even if there is no explicit description.

In addition, in the present specification,'X to Y'representing a range means'X or more and Y or less' or'≥X to ≤Y'.

Terms such as first and second used in the present specification may be used to describe various components, but the components should not be limited by terms. The terms are only used to distinguish one component from other components.

In the present specification, the'flow index' can be measured based on a load of 2.16kg at 230°C according to ASTM D1238 standard.

In the present specification,'Izod impact strength' may be measured using an Izod impact tester (TOYOSEIKI CAT NO.612) at 25°C according to the standards of ASTM D-256 (1/4 inch thickness).

In the present specification,'weight average molecular weight' may be measured using gel chromatography (GPC) and using a polystyrene standard material.

According to one aspect, the long fiber-reinforced composite material of the present invention is a polyolefin-based resin composition is impregnated into long fibers surface-treated with less than 0.1 to 1% by weight of epoxy-based resin, the polyolefin-based resin composition is 10 to ethylene Ethylene-propylene copolymer containing 15% by weight, a first polypropylene having a melt index of 500 to 2000 g/10min (230°C, 2.16 kg), a second polypropylene having Izod impact strength of 20 to 50 J/m, and Impact modifiers having maleic acid functionality.

Hereinafter, each component of the long fiber-reinforced composite material will be described in more detail.

Ethylene-propylene copolymer

The ethylene-propylene copolymer may contain 10 to 15% by weight of ethylene. In the above range, excellent impact characteristics may be imparted to the long fiber-reinforced composite material.

According to one embodiment, the ethylene-propylene copolymer may have a weight average molecular weight of 50,000 to 350,000 g/mol (eg, 100,000 to 300,000 g/mol). In the above range, the polyolefin-based resin composition may have suitable flow characteristics, and the long fiber-reinforced composite material including the same may have high impact strength.

According to one embodiment, the ethylene-propylene copolymer may have a flow index of 1 to 30 g/10min (eg, 5 to 20 g/10min). In the above range, the polyolefin-based resin composition may have suitable flow characteristics, and the long fiber-reinforced composite material including the same may have high impact strength.

According to one embodiment, the ethylene-propylene copolymer may have an Izod impact strength of 100 to 800 J/m (eg, 300 to 600 J/m). In the above range, the polyolefin-based resin composition may have suitable flow characteristics, and the long fiber-reinforced composite material including the same may have high impact strength.

The ethylene-propylene copolymer may be included in 10 to 60 parts by weight in the long fiber reinforced composite material. If the content of the ethylene-propylene copolymer is less than 10 parts by weight, the degree of improvement in impact properties may be insignificant, and if it exceeds 60 parts by weight, the flow index of the polyolefin-based resin composition may be lowered and the composition may be difficult to penetrate into long fibers. According to one embodiment, the ethylene-propylene copolymer may be included in 15 to 50 parts by weight in the long fiber-reinforced composite material. According to another embodiment, the ethylene-propylene copolymer may be included in 15 to 25 parts by weight in the long fiber-reinforced composite material, but is not limited thereto.

1st polypropylene

The first polypropylene may have a melt index of 500 to 2,000 g/10min. In the above range, it may be easy for the polyolefin-based resin composition to penetrate into long fibers. According to one embodiment, the first polypropylene may have a melt index of 1,000 to 2,000 g/10min, but is not limited thereto.

According to one embodiment, the first polypropylene may have a weight average molecular weight of 50,000 to 350,000 g/mol (eg, 80,000 to 200,000 g/mol). In the above range, the polyolefin-based resin composition may have appropriate flow characteristics.

The first polypropylene may be included in 10 to 90 parts by weight in the long fiber-reinforced composite material. If the content of the first polypropylene is less than 10 parts by weight, the flow index of the polyolefin-based resin composition is lowered, and the composition may be difficult to penetrate into long fibers, and if it exceeds 90 parts by weight, mechanical properties may be deteriorated. According to one embodiment, the first polypropylene may be included in 20 to 70 parts by weight in the long fiber-reinforced composite material. According to another embodiment, the first polypropylene may be included in 35 to 45 parts by weight in the long fiber-reinforced composite material, but is not limited thereto.

Second polypropylene

The second polypropylene may have an Izod impact strength of 20 to 50 J/m. In the above range, it is possible to impart excellent impact and stiffness characteristics to the long fiber-reinforced composite material.

According to one embodiment, the second polypropylene may have a weight average molecular weight of 50,000 to 350,000 g/mol (eg, 100,000 to 300,000 g/mol). In the above range, it is possible to provide excellent strength and rigidity to the long fiber-reinforced composite material.

According to one embodiment, the second polypropylene may have a melt index of 1 to 500 g/10min. In the above range, while allowing the polyolefin-based resin composition to easily penetrate into the long fiber, it is possible to provide excellent impact and stiffness characteristics to the long fiber-reinforced composite material. According to one embodiment, the second polypropylene may have a melt index of less than 1 to 500 g/10min. According to another embodiment, the second polypropylene may have a melt index of 10 to 50 g/10min, but is not limited thereto.

The second polypropylene may be included in 10 to 60 parts by weight in the long fiber-reinforced composite material. In the above range, it is possible to provide excellent impact characteristics and stiffness characteristics to the long fiber-reinforced composite material. According to one embodiment, the second polypropylene may be included in 15 to 50 parts by weight in the long fiber-reinforced composite material. According to another embodiment, the second polypropylene may be included in 15 to 25 parts by weight in the long fiber-reinforced composite material, but is not limited thereto.

Impact modifier

The impact modifier may have a maleic acid functional group. As a result, the bond between the ethylene-propylene copolymer, the first polypropylene and the second polypropylene, and the long fiber can be improved, thereby providing excellent impact characteristics to the long fiber-reinforced composite material.

According to one embodiment, the impact modifier may be an elastomer grafted with maleic anhydride (eg, a polyolefin elastomer grafted with maleic anhydride). For example, ethylene-octene-rubber (EOR) grafted with maleic anhydride, ethylene-butadiene rubber grafted with maleic anhydride, ethylene-propylene rubber grafted with maleic anhydride, male Ethylene/1-butene random copolymer grafted with acid anhydride, styrene-ethylene/butylene-styrene block copolymer (SEBS) with maleic anhydride grafted, ethylene-propylene-diene 3 with maleic anhydride grafted Polymers (EPDM) and the like, but are not limited thereto.

According to one embodiment, the impact modifier may have a weight average molecular weight of 50,000 to 400,000 g/mol (eg, 100,000 to 300,000 g/mol). In the above range, it is possible to provide excellent impact characteristics to the long fiber-reinforced composite material.

The impact modifier may be included in 1 to 10 parts by weight in the long fiber reinforced composite material. In the above range, it is well dispersed in the polyolefin-based resin composition and can impart excellent impact properties to the long fiber-reinforced composite material. According to one embodiment, the impact modifier may be included in 2 to 7 parts by weight in the long fiber-reinforced composite material. According to another embodiment, the second polypropylene may be included in 4 parts by weight in the long fiber-reinforced composite material, but is not limited thereto.

Long fibers

Long fibers may be surface treated (so-called sizing) with less than 0.1 to 1% by weight of epoxy resin. Here,'the surface treatment with less than 0.1 to 1% by weight of epoxy resin' means that the value of {weight of epoxy resin/(weight of epoxy resin + weight of long fiber)} X 100 is 0.1 to 1% by weight It may mean less than. In the above range, the compatibility between the ethylene-propylene copolymer, the first polypropylene and the second polypropylene and the long fibers can be improved, and the spread of the long fiber bundles increases the polyolefin-based resin composition. It can be well penetrated into the fiber. According to one embodiment, the long fiber may be surface treated with 0.1 to 0.5% by weight of an epoxy resin, but is limited thereto.

The long fiber may include, for example, carbon fiber, glass fiber, aramid fiber, natural fiber, or a combination thereof. According to one embodiment, the long fiber may be a carbon fiber (eg, PAN-based carbon fiber, pitch-based carbon fiber, etc.), but is not limited thereto.

The form of the long fiber is not particularly limited.

For example, the length of the long fibers in the long fiber-reinforced composite material may be 1 mm or more (eg, 1 to 15 mm). Here, the length of the long fiber can be measured by observing 1000 or more long fibers under a microscope. In one embodiment, the length of the long fibers in the long fiber-reinforced composite material may be 2 to 15 mm, for example, 6 to 15 mm, but is not limited thereto.

For example, the average diameter of the long fibers in the long fiber-reinforced composite material may be 1 to 30 μm (eg, 5 to 20 μm). Here, the average diameter of the long fibers can be measured by observing more than 500 fibers with an electron microscope.

For example, long fibers may be dispersed in a long fiber-reinforced composite material to have a single orientation.

The long fiber may be included in 10 to 35 parts by weight in the long fiber reinforced composite material. If the content of the long fibers is less than 10 parts by weight, the resin may flow because the polyolefin-based resin is not completely cooled among the long fiber-reinforced composite materials that have exited the impregnation section. It may degrade. According to one embodiment, the long fiber may be included in 15 to 30 parts by weight in the long fiber-reinforced composite material, but is not limited thereto.

According to one embodiment, the long fiber-reinforced composite material, specifically, a polyolefin-based resin composition may further include a modified polypropylene.

Modified polypropylene

The modified polypropylene may serve to improve compatibility between the ethylene-propylene copolymer, the first polypropylene and the second polypropylene and long fibers.

According to one embodiment, the modified polypropylene may be acid-modified propylene. For example, the modified polypropylene may be maleic anhydride grafted polypropylene, in which case the maleic acid chain improves the compatibility between the polyolefin-based resin and the long fiber so that the long fiber-reinforced composite material has excellent mechanical properties. can do.

According to one embodiment, the modified polypropylene may have a weight average molecular weight of 30,000 to 200,000 g/mol (eg, 40,000 to 150,000 g/mol).

The modified polypropylene may be included in 0.1 to 10 parts by weight in the long fiber-reinforced composite material. If the content of the modified polypropylene is less than 0.1 parts by weight, the effect of improving the compatibility between the ethylene-propylene copolymer, the first polypropylene and the second polypropylene and the long fiber may be insignificant, and if it exceeds 10 parts by weight, the desired mechanical properties It may not be possible to obtain a long fiber reinforced composite material. According to one embodiment, the modified polypropylene may be included in 1 to 5 parts by weight in the long fiber-reinforced composite material, but is not limited thereto.

In addition, the above-described long fiber-reinforced composite material may further contain antioxidants, UV stabilizers, UV absorbers, dispersants, flame retardants, colorants, flow improvers, and the like, as long as the objectives of the invention are not impaired.

According to one embodiment, the melt index of the polyolefin-based resin composition may be 100 to 300 g/10min. In the above range, impregnation properties and mechanical properties may be excellent.

According to one embodiment, the aforementioned long fiber-reinforced composite material may have a flexural strength of 166 MPa or more (eg, 170 MPa or more or 173 MPa or more), but is not limited thereto.

According to one embodiment, the aforementioned long fiber-reinforced composite material may have an impact strength of 163 J/m or more (eg, 165 J/m or more or 170 J/m or more), but is not limited thereto.

The above-described long fiber-reinforced composite material may be manufactured by applying various methods known in the art. For example, a long fiber reinforced composite material can be manufactured using a pultrusion method. For example, the above-described polyolefin-based resin composition is introduced into the resin injection unit of the pultrusion molding equipment, and the process of pulling and squeezing the long fiber in the form of a lobe (e.g., continuous fiber) while passing through the die is performed. After impregnation, the continuous strand is drawn and cooled in the impregnated state, cut into pellets, for example, 2 to 20 mm (for example, 8 to 11 mm) in size, to produce a long fiber-reinforced composite material. Can be. The length of the long fiber 　reinforced composite material pellets 　internal fiber may have a length of 2 to 20mm (for example, 8 to 11mm), and various lengths may be used depending on the purpose of use.

According to another aspect, a molded article manufactured by including the long fiber-reinforced composite material described above is provided. Since the long fiber composite material according to one embodiment of the present invention has excellent impact characteristics and bending characteristics, and has excellent impregnation properties, molded products having remarkably excellent mechanical properties when pressed/injected, such as building parts, aircraft parts, Vehicle parts, electrical products, electronic products, LED lighting products, etc. can be obtained.

Hereinafter, the configuration and operation of the present invention will be described in more detail through preferred embodiments of the present invention. However, this is provided as a preferred example of the present invention and cannot be interpreted as limiting the present invention by any means.

The contents not described herein will be sufficiently technically inferred by those skilled in the art, and thus the description thereof will be omitted.

Example

Specific specifications of the components used in Examples and Comparative Examples are as follows.

(A) Ethylene-propylene copolymer

(a1) Ethylene-propylene copolymer with ethylene content of 12% by weight (JH-370B, LCC)

(a2) Ethylene-propylene copolymer having an ethylene content of 8% by weight (JM-370, LCC)

(a1) Ethylene-propylene copolymer having an ethylene content of 20% by weight (JH-330B, LCC)

(B) 1st polypropylene: polypropylene with a flow index of 1,300 g/10min (HP461Y, Polymirae)

(C) Second polypropylene: Polypropylene with a flow index of 30 g/10min and an Izod impact strength of 29 J/m (J-170H, LCC)

(D) Impact modifier

(d1) Ethylene-octene rubber grafted with maleic anhydride having a weight average molecular weight of 267,700 g/mol (GR-216, DOW)

(d2) Ethylene-octene rubber with weight average molecular weight of 70,700 g/mol (E8407, DOW)

(d3) Ethylene-octene rubber with weight average molecular weight of 312,900 g/mol (E8842, DOW company)

(E) Modified polypropylene: PH-200 (LCC company)

(F) Long fibers

(f1) Continuous carbon fiber surface treated with 0.3% by weight of epoxy resin (TORAYCA T700-60E, TORAY)

(f2) Continuous carbon fiber surface-treated with 1% by weight of epoxy resin (TORAYCA T700-50C, TORAY)

Examples 1 and 2, and Comparative Examples 1 to 5

First, dry blending of (A) ethylene-propylene copolymer, (B) first polypropylene, (C) second polypropylene, (D) impact modifier and (E) modified polypropylene according to the composition and content of Table 1 Did. Next, (E) long fibers were prepared to be placed in a constant fiber rack so that the fibers could be placed into the impregnating die. Then, (F) the long fibers were prepared to be placed in a constant fiber rack so that the long fibers could be placed into the impregnating die. The temperature where the melted resin in the die meets the long fiber was designed to be 230 to 300°C, and was set by descending by a certain temperature toward the hopper for inputting the resin in the extruder where the resin is melted. The long fiber-reinforced composite material impregnated in the die was cooled through a cooling bath and a cooling roller, and cut into 11 mm lengths through a pelletizer. The pellets were dried in a hot air dryer at 70°C for half a day to remove all of the cooling water, thereby producing a long fiber-reinforced composite material.

Example 1 Example 2 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 (A) (a1) 24 15 - - 24 24 24 (a2) - - 24 - - - - (a3) - - 24 - - - (B) 35 35 35 35 35 35 35 (C) 15 24 15 15 15 15 15 (D) (d1) 4 4 4 4 - - 4 (d2) - - - - 4 - - (d3) - - - - - 4 - (E) 2 2 2 2 2 2 2 (F) (f1) 20 20 20 20 20 20 - (f2) - - - - - - 20

*Unit: weight%

Method for evaluating properties

(1) Flexural strength (MPa): Based on the standard of 12.7×127×6.4mm, 28mm/min according to the standard of ASTM D790, and measured using a tensile compression tester (INSTRON 4466).

(2) Izod impact strength (J/m): Measured using an Izod impact tester (TOYOSEIKI CAT NO.612) at 25° C. according to the standards of ASTM D-256 (1/4 inch thickness).

Example 1 Example 2 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Flexural strength (MPa) 173 180 161 157 159 165.5 160 Impact strength (J/m) 181 170 134 151 162 157 150

As shown in Table 2, it can be seen that the long fiber-reinforced composite material using the polyolefin-based resin composition of the present invention is excellent in both flexural strength and impact strength.

On the other hand, Comparative Examples 1 and 2 to which the ethylene content is outside the scope of the present invention is applied, Comparative Examples 3 and 4 to which an impact modifier having no maleic acid functional group is applied, and the content of the epoxy-based resin is provided in the present invention. In the case of Comparative Example 5 in which long fibers exceeding the range of, it can be seen that the flexural strength and impact strength are significantly lower than in the present invention.

In addition, as can be seen through Comparative Examples 3 and 4, while the flexural strength and impact strength characteristics of the long fiber-reinforced composite material are opposite to each other according to the weight average molecular weight of the impact modifier, the impact modifier having the maleic acid functional group of the present invention It can be seen that the long fiber-reinforced composite material included is excellent in both flexural strength and impact strength.

Simple modifications or changes of the present invention can be easily carried out by those skilled in the art, and all such modifications or changes can be considered to be included in the scope of the present invention.

Claims (8)

The polyolefin-based resin composition is impregnated into long fibers treated with an epoxy-based resin of 0.1 to less than 1% by weight,
The polyolefin-based resin composition
Ethylene-propylene copolymer containing 10 to 15% by weight of ethylene,
First polypropylene having a melt index of 500 to 2000 g/10min (230°C, 2.16 kg),
A second polypropylene having an Izod impact strength of 20 to 50 J/m, and
A long fiber reinforced composite material comprising an impact modifier having a maleic acid functional group.
According to claim 1,
The second polypropylene has a melt index of 1 to 500 g/10min (230°C, 2.16 kg), a long fiber-reinforced composite material.
According to claim 1,
The impact modifier comprises a polyolefin elastomer in which maleic anhydride is grafted, a long fiber-reinforced composite material.
According to claim 1,
The long fiber comprises a carbon fiber, long fiber reinforced composite material.
According to claim 1,
10 to 60 parts by weight of the ethylene-propylene copolymer,
10 to 90 parts by weight of the first polypropylene,
10 to 60 parts by weight of the second polypropylene,
1 to 10 parts by weight of the impact modifier, and
The long fiber reinforced composite material comprising 10 to 35 parts by weight of the long fiber.
The method of claim 5,
The long fiber-reinforced composite material further comprises 0.1 to 10 parts by weight of modified polypropylene,
The modified polypropylene comprises maleic anhydride grafted polypropylene, a long fiber reinforced composite material.
According to claim 1,
The polyolefin-based resin composition has a melt index of 100 to 300 g/10min (230°C, 2.16 kg), a long fiber-reinforced composite material.
A molded article formed from the long fiber-reinforced composite material of any one of claims 1 to 7, wherein the molded article includes a building component, an aircraft component, or a vehicle component.