KR102174303B1 - Low specific gravity sheet molding compound composite sheet - Google Patents

Abstract

SMC sheet containing a low specific gravity filler, one side forming the surface of the product; And a reinforcing material that is formed in the form of a plate, is formed to be integrated with the SMC sheet in a state of being laminated on the other surface of the SMC sheet, and reinforces the physical properties of the SMC sheet, but the reinforcing material is made of glass fiber. A low specific gravity SMC composite sheet including a mat having been introduced is introduced.

Description

Low specific gravity SMC composite sheet {LOW SPECIFIC GRAVITY SHEET MOLDING COMPOUND COMPOSITE SHEET}

The present invention relates to a low specific gravity SMC composite sheet, to a composite sheet reinforced with the SMC sheet containing a low specific gravity filler.

SMC (Sheet Molding Compound) is manufactured in a sheet form by dispersing short glass fibers in a sheet body made of a thermosetting resin and then press-molding to form a sheet. Because it is easy to mold, it manufactures housing-related parts, automobile-related parts, and other parts. It is used as a composite material.

Such SMC is a sheet-like molding material having high viscosity, non-adhesiveness, and excellent moldability, and has excellent mechanical strength after molding compared to its density, and its price is low, so its demand is gradually increasing.

In particular, when SMC is applied to an exterior panel, it is possible to manufacture a low specific gravity SMC including a filler because the conditions of weight reduction and surface quality are important. However, in the case of low specific gravity SMC, there is a problem that the surface quality is satisfactory but physical properties are deteriorated. Accordingly, there is a need for a reinforcing material capable of improving physical properties such as tensile strength and tensile stiffness while satisfying the conditions of weight reduction and surface quality.

The matters described as the background art are only for enhancing an understanding of the background of the present invention, and should not be taken as acknowledging that they correspond to the prior art already known to those of ordinary skill in the art.

KR 10-1811993 B

The present invention has been proposed to solve this problem, and is to provide a low specific gravity SMC composite sheet that reinforces the physical properties of the SMC sheet while maintaining light weight and surface quality.

The low specific gravity SMC composite sheet according to the present invention for achieving the above object includes a low specific gravity filler, SMC sheet having one side forming the surface of the product; And a reinforcing material that is formed in the form of a plate, is formed to be integrated with the SMC sheet in a state of being laminated on the other surface of the SMC sheet, and reinforces the physical properties of the SMC sheet, but the reinforcing material is made of glass fiber. Includes a mat having been.

The low specific gravity filler included in the SMC sheet may be a glass sphere or pearlite having a hollow bead shape.

As the reinforcing material is press-molded inside the mold together with the SMC sheet, the SMC sheet penetrates into the inside of the reinforcement material and can be integrated with the reinforcement material.

Based on the thickness of the SMC sheet is 1.85 [mm], the reinforcing material may be greater than 70 [gsm] and less than 140 [gsm].

Where gsm is gram per square meter.

The composite sheet in which the SMC sheet and the reinforcing material are integrated may be molded to a thickness of 2 [mm] or less.

According to the low specific gravity SMC composite sheet of the present invention, while maintaining the surface quality of the SMC sheet forming the surface of the product and the specific gravity of the product, it has the effect of reinforcing physical properties including tensile strength and tensile stiffness.

1 is a cross-sectional view of a low specific gravity SMC composite sheet according to an embodiment of the present invention.
Figure 2 shows the manufacturing process of the low specific gravity SMC composite sheet according to an embodiment of the present invention.

Specific structural or functional descriptions of the embodiments of the present invention disclosed in this specification or application are exemplified only for the purpose of describing the embodiments according to the present invention, and the embodiments according to the present invention may be implemented in various forms. And should not be construed as limited to the embodiments described in this specification or application.

Since the embodiments according to the present invention can be modified in various ways and have various forms, specific embodiments are illustrated in the drawings and will be described in detail in the present specification or application. However, this is not intended to limit the embodiments according to the concept of the present invention to a specific form of disclosure, and it should be understood that all changes, equivalents, and substitutes included in the spirit and scope of the present invention are included.

Terms such as first and/or second may be used to describe various components, but the components should not be limited by the terms. The terms are only for the purpose of distinguishing one component from other components, for example, without departing from the scope of the rights according to the concept of the present invention, the first component may be named as the second component, and similarly The second component may also be referred to as a first component.

When a component is referred to as being "connected" or "connected" to another component, it is understood that it may be directly connected or connected to the other component, but other components may exist in the middle. Should be. On the other hand, when a component is referred to as being "directly connected" or "directly connected" to another component, it should be understood that there is no other component in the middle. Other expressions describing the relationship between components, such as "between" and "just between" or "adjacent to" and "directly adjacent to" should be interpreted as well.

The terms used in the present specification are only used to describe specific embodiments, and are not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In the present specification, terms such as "comprise" or "have" are intended to designate the presence of a set feature, number, step, action, component, part, or combination thereof, but one or more other features or numbers It is to be understood that the presence or additional possibilities of, steps, actions, components, parts, or combinations thereof are not excluded in advance.

Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which the present invention belongs. Terms as defined in a commonly used dictionary should be interpreted as having a meaning consistent with the meaning in the context of the related technology, and should not be interpreted as an ideal or excessively formal meaning unless explicitly defined in the present specification. .

Hereinafter, the present invention will be described in detail by describing a preferred embodiment of the present invention with reference to the accompanying drawings. The same reference numerals in each drawing indicate the same member.

1 is a cross-sectional view of a low specific gravity SMC composite sheet according to an embodiment of the present invention, Figure 2 shows a manufacturing process of the low specific gravity SMC composite sheet according to an embodiment of the present invention.

1 to 2, the low specific gravity SMC composite sheet according to an embodiment of the present invention includes a low specific gravity filler, SMC sheet 10 on one side forming the surface of the product; And a reinforcing material 20 formed in a plate shape and formed to be integrated with the SMC sheet 10 in a state laminated on the other surface of the SMC sheet 10, and reinforcing the physical properties of the SMC sheet 10. However, the reinforcing material 20 includes a mat made of glass fiber.

The SMC sheet 10 is manufactured by the SMC sheet 10 manufacturing apparatus, and may be manufactured by injecting a paste in which additives such as a resin, a curing accelerator, and a release agent are mixed between carrier films positioned on both sides. As the resin, a thermosetting resin such as an unsaturated polyester resin or a vinyl ester resin is mainly used.

The SMC sheet 10 is impregnated with glass fibers to improve its rigidity. The ratio of the glass fiber and the resin is adjusted in consideration of the specific gravity, and as the ratio of the glass fiber increases, the specific gravity of the SMC sheet 10 increases, and as the ratio of the glass fiber decreases, the specific gravity of the SMC sheet 10 decreases.

In particular, the SMC sheet 10 of the present invention is used for a product such as an exterior panel applied to a vehicle and the like, and includes a low specific gravity filler to satisfy weight reduction of the product. In addition, it can maintain the surface quality including the surface strength of the product. One side of the SMC sheet 10 may be disposed to form the surface of the product.

The reinforcing material 20 may be laminated on the other surface of the SMC sheet 10 to be integrally combined with the SMC sheet 10. The reinforcing material 20 may be made of glass fiber, carbon fiber, carbon fiber or aramid fiber, but in particular, in order to satisfy the physical properties required for the product, it is preferable that it is a mat made of glass fiber.

The mat made of glass fiber may be used in a state of overlapping one mat or a plurality of mats based on a mat having 70 [gsm] in the form of a veil.

The reinforcing material 20 may be stacked on the entire other surface of the SMC sheet 10 or only in a partial area of the other surface that requires reinforcement. Accordingly, it has the effect of reinforcing local physical properties.

As the reinforcing material 20 is molded to be integrated with the other surface of the SMC sheet 10, the surface quality of the outer surface of the product is maintained, and the overall physical properties of the low specific gravity SMC composite sheet are improved.

The low specific gravity filler included in the SMC sheet 10 may be glass spheres or pearlite having a hollow bead shape.

The low specific gravity filler is included inside the SMC sheet 10 to reduce the specific gravity of the SMC sheet 10 and improve the surface quality of the SMC sheet 10. In particular, the low specific gravity filler may be formed in a hollow bead shape to further reduce specific gravity, and may be formed of a material such as glass sphere or pearlite.

As the reinforcement material 20 is press-molded in the mold 30 together with the SMC sheet 10, the SMC sheet 10 may penetrate into the reinforcement material 20 and be integrated with the reinforcement material 20.

As shown in FIG. 2, the reinforcing material 20 may be inserted into the mold 30 at the same time as the SMC sheet 10 to be press-molded. Resin contained in the SMC sheet 10 by press molding may be molded so as to penetrate into the inside of the reinforcing material 20, and accordingly, the reinforcing material 20 may be integrated with the SMC sheet 10.

That is, the reinforcing material 20 may be a material in which SMC penetrates into a mat made of glass fiber and is integrated. The interface between the SMC sheet 10 and the reinforcing material 20 may have surface quality and physical properties between the surface quality and physical properties of the SMC sheet 10 and the reinforcing material 20.

As SMC penetrates into the reinforcement material 20 and is integrated, even if a mat made of glass fiber is added, the thickness of the low specific gravity SMC composite sheet may be increased at the same ratio as the weight so that the specific gravity is maintained.

Table 1 is a comparison of the unit weight of the SMC sheet 10 and the SMC sheet 10 including the reinforcing material 20 in the SMC sheet 10.

Referring to Table 1, in the case of press-molding by adding the reinforcing material 20 to the SMC sheet 10 of 1.85 [mm], the design specific gravity can be designed to be the same, and accordingly, the thickness and weight are increased in the same ratio and the unit The weight can remain the same.

Table 2 shows the surface quality and physical properties according to varying the number of glass fiber mats having a thickness of 1.85 [mm] SMC sheet 10 to 70 [gsm].

Referring to Table 2, the reinforcing material 20 may contain more than 70 [gsm] and less than 140 [gsm] of glass fibers.

If the reinforcing material 20 is not included or if less than two glass fiber mats having 70 [gsm] are included, the surface quality is good, but if three or more glass fiber mats having 70 [gsm] are included, the surface Due to the deterioration of the quality, a problem that is difficult to apply to the surface of the product occurs.

In addition, when the reinforcing material 20 is not included or a glass fiber mat having 70 [gsm] is included within one sheet, a problem occurs in that the tensile strength or tensile stiffness is less than the standard value.

Considering all these circumstances, the reinforcing material 20 is molded so that the thickness of the SMC sheet 10 according to an embodiment of the present invention is greater than 70 [gsm] and less than 140 [gsm]. Would be desirable.

Particularly, in the case of including a glass fiber mat having 70 [gsm] in the present invention, it is preferable that two glass fiber mats having 70 [gsm] are included.

Accordingly, in the product to which the low specific gravity SMC composite sheet according to the present invention is applied, it has an effect of satisfying both physical properties and surface quality including tensile strength and tensile stiffness.

In addition, the composite sheet in which the SMC sheet 10 and the reinforcing material 20 are integrated may have a thickness of 2 [mm] or less. Accordingly, it has the same or similar specific gravity as a product manufactured only with the existing SMC sheet 10, and has an effect of reinforcing physical properties without significantly increasing the thickness.

Table 3 is a comparison of physical properties between the SMC sheet 10 and the SMC composite sheet. Here, the SMC composite sheet includes two glass fiber mats having 70 [gsm].

Referring to Table 3, the effect of the SMC composite sheet having higher tensile strength and tensile stiffness than the conventional SMC sheet 10 can be confirmed. In particular, the SMC composite sheet can be designed to satisfy the target tensile strength of 90 [MPa] and the target tensile strength of 9 [GPa].

Although illustrated and described in connection with specific embodiments of the present invention, it is understood in the art that the present invention can be variously improved and changed within the scope of the technical spirit of the present invention provided by the following claims. It will be obvious to a person of ordinary knowledge.

10: SMC sheet 20: reinforcement
30: mold

Claims (5)

SMC sheet containing a filler having a hollow bead shape, one side forming the surface of the product; And
Including; a reinforcing material formed in the form of a plate and formed to be integrated with the SMC sheet in a state laminated on the other surface of the SMC sheet, and reinforcing the physical properties of the SMC sheet,
The reinforcing material includes a mat made of glass fiber, and as the SMC sheet is press-molded inside the mold together with the SMC sheet, the SMC sheet penetrates into the interior of the reinforcement material and is integrated with the reinforcement material. The method according to claim 1,
Low specific gravity SMC composite sheet, characterized in that the filler included in the SMC sheet is glass spheres or pearlite. delete The method according to claim 1,
Based on the thickness of the SMC sheet is 1.85 [mm], a low specific gravity SMC composite sheet, characterized in that the reinforcing material contains more than 70 [gsm] and less than 140 [gsm] of glass fibers.
Where gsm is gram per square meter. The method of claim 4,
A low specific gravity SMC composite sheet, characterized in that the composite sheet in which the SMC sheet and the reinforcing material are integrated has a thickness of 2 [mm] or less.

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