KR20010054149A - Process of resin composition - Google Patents

Abstract

PURPOSE: A resin composition producing method for the outside plate of a vehicle body is provided to reduce the weight of the outside plate and a raw cost by newly producing a hand lay-up material in a high intensity and low specific gravity type, better than a glass fiber reinforced plastic, using a complex material selectively mixed with glass fiber, carbon fiber and kevlar fiber. CONSTITUTION: Unsaturated polyester resin is coated on a mold and a reinforcing material selectively mixed with glass fiber, carbon fiber and kevlar fiber is layered in two to five layers. Then, the resin is molded in a land lay-up method. The unsaturated polyester resin includes 15 to 60wt% of the reinforcing material. The unsaturated polyester resin is selected from denatured bisphenol grouped resin, bisphenol grouped resin, iso-grouped resin, ortho-grouped resin, tere-grouped resin and vinyl ester grouped resin. The reinforcing material is selected from a chopped strand mat shape, a woven roving shape, cloth shape or a yarn shape.

Description

Process for producing resin composition for vehicle body exterior plate

The present invention relates to a method for producing a resin composition for vehicle body panels, and more particularly, to a method for manufacturing a resin composition for vehicle body panels, selected from among glass fibers, carbon fibers, and kevlar fibers that are generally used alone as reinforcement materials for vehicle body panels. By using the material together to provide a resin composition with better physical properties than conventional glass fiber reinforced plastic (GFRP), and manufacturing the resin composition by the hand lay-up method, manufacturing process The present invention relates to a method for manufacturing a vehicle exterior resin composition capable of simplifying and reducing the weight and cost of a product.

The outer shell of a car body can withstand the impact of the outside, and requires a certain level of rigidity, and the products used for this are generally steel panel products and plastic products. Such steel panel products and plastic products are distinguished from materials and manufacturing methods, respectively, and the characteristics thereof are as follows.

First, a steel sheet (SPRC35) is generally used as a material used for a vehicle body plate product, and is manufactured by pressing a sheet using a mold after cutting the coil-shaped steel sheet to a certain size. However, the above method usually requires 3 to 4 molds in order to obtain the required shape due to the forming characteristics of the steel sheet, which causes a complicated manufacturing process and high mold and facility investment costs. In addition, although the steel product manufactured by the press method is thin as 0.7t, the specific gravity is about 7.8, which is not preferable because the weight of the molded article is heavy.

In contrast, the plastic product used in the present invention is a hand lay-up method using a composite material that mixes an unsaturated polyester (UP) resin and a glass fiber, which is mainly manufactured a prototype Or it is a mass production method that can be applied to a special field where the annual output is very low, which is used as a built-in panel of electric cars and ships.

Physical properties of the plastic composite material is mainly determined by the type and content of the resin, reinforcing material, filter and the like used. In the case of the thermosetting plastic composite material manufactured by the hand lay-up method, an unsaturated polyester (UP) is used as the resin and glass fiber (GF) is used as the reinforcing material. They are the least expensive in terms of price but are not preferred because of their limited physical properties. When the glass fiber reinforced plastic product is 2.5t thick, it is thicker than the steel product manufactured by the press method, but the specific gravity is about 1.5, and the panel weight is about 30% lighter than the steel product. That is, the thickness of the glass fiber reinforced plastic panel should be at least 2.5 mm in order to have the same level of stiffness of the steel panel when applied to the body shell, there is a problem that the weight reduction effect is only up to about 30%.

As described above, since the resin composition applied to a conventional vehicle body shell plate causes the above problems, there is a demand for a new method for producing a resin composition for vehicle body shell plate having excellent physical properties and excellent weight reduction effect.

Accordingly, the present invention is to solve the problems as described above, in order to replace the steel (steel) that is currently used as a material for the exterior of the automobile body with plastic, among the glass fiber and carbon fiber and Kevlar fiber used alone as a general reinforcement By using the selected composite materials together, we have developed a new high-strength low-weight hand lay-up material that is superior to the existing glass fiber reinforced plastic (GFRP). It is an object of the present invention to provide a method for producing a resin composition for automobile exterior panels, which can achieve cost reduction.

The present invention gel-coated an unsaturated polyester resin on a mold, and then laminated a reinforcing material selected from glass fibers, carbon fibers and Kevlar fibers in two to five layers, by a hand lay-up method The manufacturing method of the resin composition for vehicle body outer panels manufactured by shape | molding is characterized by the above-mentioned.

Referring to the present invention in more detail as follows.

The present invention, when manufacturing the resin composition for the outer shell of the vehicle body by a hand lay-up method, which is a kind of plastic composite material manufacturing method, to replace the steel (steel) currently used as a vehicle outer shell material with plastic, as a general reinforcement By using the glass fiber used together with carbon fiber or Kevlar fiber, it has a high strength, low specific gravity, hand lay-up material, which is superior to glass fiber reinforced plastic (GFRP). The present invention relates to a resin composition for a car shell that can be newly developed to achieve weight reduction and cost reduction.

In the present invention, an unsaturated polyester resin is mainly used as a raw material resin in the composition of the outer shell resin composition, and a vinyl ester resin is also used to increase the heat resistance stability of the molded product at a high temperature. The unsaturated polyester resin according to the present invention may be selected from modified bisphenol-based, bisphenol-based, iso-based, ortho-based, tere-based and vinyl ester-based resins.

In addition, the present invention is characterized in that the carbon fiber or Kevlar fiber is used together with the glass fiber as a reinforcing material in order to improve the physical properties of the resin composition and increase the weight reduction effect. That is, the present invention may be used alone or mixed as a reinforcing material selected from glass fiber, carbon fiber and Kevlar fiber.

In the present invention, it is preferable to use the use content of the reinforcing material in 15 to 60 parts by weight, but if the use content is less than 15 parts by weight, there is a problem in that the thickness is insufficient to increase the thickness, whereas the excess exceeds 60 parts by weight. If it is used as a poor impregnation with the raw material resin rather poor moldability and may cause a decrease in physical properties such as strength is not preferred.

The shape of the reinforcement used in the present invention is in the form of chopped strand mat (CSM), or woven roving (WR), cloth (Cloth) form and You can choose from Yarn type.

In addition, the specific gravity of the composite material according to the present invention is proportional to the volume fraction of the resin and the reinforcing material. Since the specific gravity of the unsaturated polyester resin, which is a raw material resin, is 1.2, and the specific gravity of glass fiber, carbon fiber and kevlar fiber is 2.5, 1.8 to 2.0 and 1.4, the weight reduction effect at the same thickness increases in the order of Kevlar fiber> carbon fiber> glass fiber. Done.

In the present invention, E-glass or S-glass may be used as the glass fiber, or PAN system pitch may be used as the carbon fiber. In addition, MEKPO (methylethylkethone peroxide) or BPO (benzoyl peroxide) may be mainly used for a conventional curing reaction, and may be used in the range of 0.1 to 5 parts by weight in the present invention.

On the other hand, the Hand Lay-Up (HLU) method characterized by the present invention is a manufacturing method of molding a composite material by hand as the most cost-effective manufacturing technology. The hand lay-up method does not have upper and lower molds unlike sheet molding compound (SMC) or resin transfer molding (RTM).

In particular, the hand lay-up method used in the present invention is obtained in the present invention in the case of a hood, tailgate, door, etc., in which a part is composed of a combination of an inner panel and an outer panel. The use of the resin composition can achieve weight reduction effectively.

Referring to the manufacturing method of the resin composition for a vehicle body plate using the hand lay-up method of the present invention in more detail as follows.

First, the present invention manufactures a master model (also called a mold or a mock up), and then manufactures a mold from a fiber reinforced plastic (FRP) or epoxy based on this.

In the present invention, after the mold is manufactured, the gel is coated thereon, and then the reinforcing fiber is laid and cured at room temperature while impregnating the raw material resin using a roller by hand. The curing time is usually about 5 to 15 minutes, and before the complete curing, the reinforcing fibers are laid again and laid-up according to the required thickness of the molded article, but the thickness is in the range of 1.0 to 4.5 mm, The number of laminated sheets is 2 to 5 ply in total, and the glass fibers and the carbon fibers may be laminated together or the glass fibers and the kevlar fibers may be laminated together.

From the results of the present invention as described above, in the case of the hand lay-up method material, an optimal material may be selected in consideration of the weight reduction effect and physical properties. In other words, for the inner panel, the resin uses SR825 (reinforcement), the reinforcement uses carbon fiber, the outer panel uses SR825 and the reinforcement uses Kevlar fiber, which simultaneously increases performance and light weight. You can.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited by Examples.

Comparative Example 1

Next, after forming a plate-shaped mold forming mold (mold) with the composition as shown in Table 1, using a raw material as shown in the following gel-coated, laminated with a predetermined thickness using an unsaturated polyester resin and Woven cloth glass fiber Molded. The number of laminated reinforcing materials used was three ply, and the thickness of the final molded product was 2.4 mm. Specifically, unsaturated polyester resin GC 230 (Aekyung Industrial) as a resin for gel coating, unsaturated polyester resin R235 (general grade, sewon) as a matrix resin, and glass fiber as a stiffener, WR570, Korea owense- corning) was used. The physical properties of the test specimens collected from the molded articles were measured, and the results are shown in Table 2 below.

Comparative Example 2

It produced in the same manner as in Comparative Example 1, but instead of the unsaturated polyester resin bisphenol-based vinyl ester (SR825: ultra heat resistance grade, sewonhwa) was used, the thickness was 2.3mm.

Example 1

In the same mold as in Comparative Example 1 was produced in the same manner, but was molded using a carbon fiber (Woven roving form, CF6638, Korea Carbon) at the same time as a reinforcing material. The stacking order was 3 layers in order of 2 layers of glass fiber and 1 layer of carbon fiber, and the final molding thickness was 2.2 mm.

Example 2

The same mold as in Example 1 was produced, but was molded using Kevlar fiber (Woven roving form, HK285, Carbon Korea) as a reinforcing material. The stacking order was 3 ply with one layer of Kevlar fiber on the last layer, and the final molding thickness was 2.9mm.

Examples 3-6

In the same mold as in Example 1, the same content and method were used, but the carbon fiber and the kevlar fiber were formed by using the carbon fiber and the kevlar fiber in three layers instead of two or each of the glass fiber as the reinforcing material. The final molding thicknesses were 2.1, 1.7, 2.0 and 1.5 mm, respectively.

Example 7

It was prepared in the same manner as in Example 5 except that bisphenol-based vinyl ester (SR825: ultra heat-resistant grade, thinning resistance) was used in place of the unsaturated polyester resin, and the final molded product had a thickness of 2.0 mm.

Examples 8-10

It was manufactured in the same manner as in Example 7, but was molded using two layers of glass fibers, two layers of Kevlar fibers, three layers of Kevlar fibers and five layers of Kevlar fibers as one reinforcing material. The final moldings were 2.7, 2.5 and 2.6 mm thick, respectively, and the physical properties are shown in Table 2 below.

As can be seen in Table 2, the resin composition according to the present invention was increased as the number of lamination of carbon fiber and Kevlar fiber in the case of tensile strength was increased, the flexural strength of Examples 1, 2, 3 and laminated 4 showed better physical properties. Tensile modulus and flexural modulus increased with increasing number of carbon fibers and Kevlar fibers. In Examples 7 to 11 manufactured using heat resistant resins, physical properties were improved by about 10 to 20% compared to Examples 1 to 6 prepared using general resins.

Therefore, since the resin of the present invention has a stiffness proportional to the elastic modulus x (thickness) ³ , it is theoretically possible to further reduce weight by about 30% and 25% when using carbon fiber and Kevlar fiber. Therefore, the use of carbon fibers makes it possible to reduce the weight of steel panels by about 40%.

In addition, when Kevlar fiber is used instead of glass fiber as the reinforcing material, the specific gravity is low, and the weight reduction effect may be additionally expected at the same thickness. Since specific gravity is proportional to the part weight, carbon fiber and Kevlar fiber can theoretically achieve about 7% and 15% additional weight reduction compared to glass fiber reinforced composites. Therefore, the use of Kevlar fibers makes it possible to reduce the weight of steel panels by about 35%.

In addition, if the material developed in the present invention is applied to the outer shell part of the future development, carbon fiber is most advantageous in terms of the weight reduction effect as the material of the inner panel of the parts composed of the inner and outer panels, such as a door panel assay. One-piece panels, such as exterior panels or roof panels and side exterior panels of components consisting of internal and external panels, must maintain a constant thickness of 2.5 tonnes, so using Kevlar fiber is the most advantageous in terms of light weight. Do. In addition, since only 10-20% of physical properties can be improved by changing only the raw material resin, it was confirmed that weight reduction of 40% or more with respect to the steel panel can be achieved when selecting the optimum material.

In addition, when the resin composition prepared in the present invention is applied to a vehicle body shell, there is an effect of improving dent resistance, vehicle rigidity, corrosion resistance, and design freedom.

As described above, the resin of the present invention can be used in combination with carbon fiber or Kevlar fiber instead of glass fiber alone as a reinforcing material, excellent physical properties and can be expected to reduce the weight by reducing the thickness, hand lay Because it uses up-up method, it is economical because it can simplify manufacturing process than press method for manufacturing steel products.

Claims (4)

Gel-coated unsaturated polyester resin on the mold, and then laminated by reinforcing material selected from glass fibers, carbon fibers and Kevlar fibers in two to five layers, and molded by the hand lay-up method The manufacturing method of the resin composition for vehicle body exterior panels characterized by the above-mentioned. The method of claim 1, wherein the unsaturated polyester resin contains 15 to 60 parts by weight of a reinforcing material selected from glass fiber, carbon fiber and Kevlar fiber with respect to 100 parts by weight of unsaturated polyester resin. Manufacturing method. According to claim 2, wherein the unsaturated polyester resin is selected from modified bisphenol-based, bisphenol-based, iso-based, ortho-based, tere-based and vinyl ester-based resin composition Manufacturing method. The method of claim 1, wherein the reinforcing material is selected from the shape of chopped fiber mat (Chopped Strand Mat), woven roving (Woven Roving), cloth (Cloth) form or yarn (Yarn) characterized in that The manufacturing method of the resin composition for vehicle exterior panels.