JPH05185540A - Molded form of thermoplastic composite material for structure and manufacture thereof - Google Patents

Abstract

PURPOSE:To prevent the sag, learance, etc., of a joining section by installing a member, in which a specific composite blank is laminated and preformed, and a member, in which the composite blank is laminated similarly and joined partially, while adopting a means, in which the non-joining section of one member is bent and abutted against the other member. CONSTITUTION:A molded form 1 is formed from a first member 2, in which a plurality of composite blanks composed of reinforcing fibers and a thermoplastic resin are laminated and preformed, and a second member 3, in which a plurality of the same blanks are laminated and joined partially. A plurality of blank sheets 31 are laminated and joined through the welding, etc., of spots 34 in a joining section 32 in the second member 3 at that time. The non-joining section 33 of the second member 3 is bent, and the second member is cemented to the first member 2. Both members 2, 3 are heated at a temperature higher than the melting point or higher of the thermoplastic resin and pressed, and formed integrally. Accordingly, a molded form for a structural material having excellent joint strength is obtained without generating a sag, a clearance, etc., in the joining section 32.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a molded article of a thermoplastic composite material for a structural material and a method for producing the same, and in particular, it is formed by combining members of the thermoplastic composite material, and there is no slack or a gap at the joint portion. The present invention relates to a molded body of a thermoplastic composite material having a good bonding strength and the like and a method for producing the same.

[0002]

2. Description of the Related Art Various composites can be obtained by laminating sheets obtained by combining reinforcing fibers such as carbon fibers and various matrix resins with each other and then heating and pressurizing them. It is used in various fields. In particular, those using a thermoplastic resin as a matrix resin are widely used for various home electric appliances, machine parts, automobile parts, structural materials, etc., because they can be easily molded.

When such a thermoplastic composite material is used as a structural material, for example, when it is made into an H-shaped material, as shown in FIG. 5, two flat plate-shaped composite materials 51 and 52 and both ends thereof are arranged in almost two directions. The vertically bent composite material 53 is manufactured in advance, and the flat plate-shaped composite materials 51, 52 and the composite material 53 are brought into contact with each other and joined by heating and pressurizing.

However, when the composite material 53 is bent at both ends, the inner layer is sagged due to the difference in radius between the inner and outer layers at the bent portion. Furthermore, composite materials 51, 52
Since the solidified material and the composite material 53 are in contact with each other and it is difficult to form the bent portion of the composite material 53 at a right angle, a gap is generated at the contacting portion a, and heating / heating is performed. At the time of joining by pressure, this becomes a void, becomes resin rich, or causes the inflow of reinforcing fibers, and as a result, the strength of the joint between the composite material 51, 52 and the composite material 53 is sufficient. There is a problem that it disappears.

For the purpose of preventing slack, the length of each sheet is set in advance so that the bent composite material becomes longer in advance as it goes to the outer layer, and a desired shape of the mold or jig is bent. Laminate with to make a preform,
It may be considered that this is produced by heating and pressurizing, but in the above method, there is a problem that it takes time to make the length of each layer appropriate. Moreover, since the gap a at the contact portion still remains, there is a problem that the strength is still insufficient.

[0006] Therefore, an object of the present invention is to provide a molded article of a thermoplastic composite material for structural materials, which has no slack, gaps, etc. at the joint and has good joint strength.

Another object of the present invention is to provide a method for producing a molded body of a thermoplastic composite material for the above structural material.

[0008]

As a result of earnest research in view of the above object, the present inventors have made a first member by laminating a plurality of composite materials composed of reinforcing fibers and a thermoplastic resin and preforming them. And a plurality of composite materials composed of a reinforcing fiber and a thermoplastic resin are laminated and used in combination with a second member partially joined to bend the non-joined portion of the second member By contacting with the member of, and maintaining this under pressure at a temperature lower than the melting point of the thermoplastic resin for a certain period of time, the second member slides, the deflection and the gap of the contact portion are eliminated,
After that, if heated and pressed at a temperature higher than the melting point of the resin and integrally molded, a molded product of the structural thermoplastic composite material with good bonding between the first member and the second member can be obtained. And found the present invention.

That is, the molded body of the structural thermoplastic composite material of the present invention comprises the first member formed by laminating a plurality of composite materials composed of the reinforcing fiber and the thermoplastic resin and preforming, and the reinforcing fiber. It is composed of a second member formed by laminating a plurality of composite materials made of thermoplastic resin and partially bonding them, and the non-bonding part of the second member is bent and abuts on the first member. And is integrally molded by being heated and pressed at a temperature equal to or higher than the melting point of the thermoplastic resin.

Further, the method of the present invention for producing a molded body of the above-mentioned structural thermoplastic composite material comprises (A) laminating a plurality of composite materials composed of reinforcing fibers and a thermoplastic resin, and melting point of the thermoplastic resin. By heating and pressurizing at the above temperature to form the first member by preforming, (B) by laminating a plurality of composite materials consisting of reinforcing fibers and thermoplastic resin, and by partially bonding A second member is formed, (C) the non-bonded portion of the second member is bent and brought into contact with the first member, (D) pressure is applied in a temperature region lower than the melting point of the thermoplastic resin, (E) ) After that, heating and pressurization are performed at a temperature equal to or higher than the melting point of the thermoplastic resin.

[0011]

The present invention will be described in detail below with reference to the accompanying drawings.

First, the molded article of the thermoplastic composite material of the present invention will be described. FIG. 1 is a perspective view schematically showing an example of a preformed body of a molded body of the structural thermoplastic composite material of the present invention.

The preform 1 comprises a first member 2 formed by laminating and preforming a plurality of composite materials composed of reinforcing fibers and a thermoplastic resin, and a plurality of reinforcing members and a thermoplastic resin. The second member 3 is formed by laminating composite materials and partially joining them.

In the present invention, examples of the thermoplastic resin as the base material of the first member include polyether ether ketone (PEEK), polyamide such as nylon, polyester such as polyethylene terephthalate and polybutylene terephthalate, polyacetal, polyphenylene sulfide, Crystalline thermoplastic resins such as polyetherketone may be mentioned. PEEK is particularly preferable.

PEEK has a weight average molecular weight of 6.5.
It is preferable to use one having a molecular weight of about 10 ^{4 to} 9.4 10 ⁴ (relative molecular weight based on polystyrene molecular weight).

Further, as the reinforcing fiber to be composited with the above-mentioned thermoplastic resin, it is possible to use carbon fiber, glass fiber, boron fiber or the like, which is a reinforcing long fiber used in ordinary composite materials. Among the above-mentioned thermoplastic resins, PEE
When a fiber-reinforced composite material having a matrix phase other than K and polyetherketone is used, aramid fibers may be used in addition to the above-mentioned reinforcing fibers. The diameter of the reinforcing fiber is about 3 to 200 μm.

The first member 2 is, for example, a woven fabric formed by weaving fibers made of the above-mentioned thermoplastic resin and reinforcing fibers into a plain weave, a satin weave, a twill weave, or a film made of a thermoplastic resin. And a reinforced fiber, and a woven fabric composed of the fiber and the reinforced fiber and a thermoplastic resin film are used together, and these woven fabrics or films are laminated, and the melting point of the thermoplastic resin used is +30 to 40 ° C., 3 to It can be obtained by heating at a pressure of 6 kg / cm ² for 10 to 20 minutes.
When PEEK is used as the thermoplastic resin, it is preferable that the heating temperature is 370 to 380 ° C. and the pressure is 4 to 6 kg / cm ² .

An enlarged view of the second member 3 is shown in FIG. The second member 3 is formed by stacking four material sheets 31 and is joined at a joining portion 32. In the non-joint portion 33, each of the four material sheets is bent into two,
As will be described later, it is brought into contact with the first member. In this embodiment, the joining is performed by spot welding using ultrasonic waves, and the stacked bodies are joined by arranging the spots 34 at a constant pitch.

The second member as described above is formed, for example, by laminating sheet-shaped materials on a flat plate and ultrasonically welding the laminated body.
It can be manufactured by joining at a desired position by laser welding, welding with a soldering iron, stitching, heat pressing or the like. Of these, spot welding using ultrasonic waves is particularly preferable.

As the thermoplastic composite material for the second member, the same material as the above-mentioned first member can be used.

Next, a method for producing a molded body of the structural thermoplastic composite material of the present invention using such a first member and a second member will be described.

First, as shown in FIG. 1, bagging is performed with the first member 2 and the second member 3 in contact with each other. Then press at a suitable pressure and below the melting point of the thermoplastic resin set. Specifically, when PEEK is used as the resin component, it is desirable to apply a pressure of at least 9.9 kg / cm ² at a temperature below the melting point (343 ° C.) of PEEK.

When the heating temperature exceeds the melting point of the resin, the first member 2 and the second member 3 are fused at the contact point, and it is difficult to bring them into close contact without any gap. The pressure is 1kg / cm
^When it is less than ² , it becomes difficult to join the first member and the second member without a gap.

When the material is heated and pressurized and held at a temperature equal to or lower than the melting point of the resin component in this manner, each material of the second member slides in a portion in contact with the first member. The gap a at the contact point between the first member 2 and the second member 3 shown in FIG. In the second member, since the material sheets are not joined at the position where the second member contacts the first member, each material sheet slides according to the bending, so that wrinkles, slack, folds, etc. may occur with the bending. There is no. In particular, by sucking air during bagging, both members can be brought into closer contact with each other.

Subsequently, the melting point of the resin + 40-60 while being pressurized
The resin is melted by heating and pressurizing at a temperature of ℃, impregnation of the resin component that becomes the matrix, and joining of the first member and the second member. The heating needs to be at a temperature sufficient to melt the resin and impregnate the reinforcing fibers, but in the case of the PEEK resin, specifically, it is preferably 390 to 400 ° C. The pressure applied is preferably 14 to 20 kg / cm ² .

In this way, the thermoplastic composite material thus obtained has no slack or air mixture at the joint portion between the first member 2 and the second member 3, so that a void is generated therein or a resin is formed. It is suitable for various structural materials because it has sufficient strength at the joint portion without becoming rich or causing inflow of reinforcing fibers.

Although the present invention has been described with reference to the accompanying drawings in the case of a T-type composite material, the present invention is not limited to this, and for example, in the case of an H-type composite material, the second member is used. It suffices to bend both ends of and to bring them into contact with the two first members. Further, a plurality of second members may be joined to one first member. In this way, the pattern of the combination of the first member and the second member can be appropriately set according to the desired shape of the structural material.

The present invention will be described in more detail with reference to the following specific examples. Example 1 Plain woven fabric of carbon fiber and PEEK fiber (average diameter of carbon fiber is 7 μm, average diameter of PEEK fiber is 40 μm, 8 cm
X 30 cm) was laminated 34 and heated at 380 ° C. and 5 kg / cm ² for 15 minutes to produce a first member.

Further, four flat woven fabrics (23 cm × 30 cm) of the above carbon fibers and PEEK fibers were laminated and spot welded by ultrasonic waves leaving 4 cm at both ends, to manufacture a second member. In addition, ultrasonic welding uses a 10 mmφ horn
15kHz ultrasonic wave, oscillation time 1 second, pressurizing pressure 10kg / cm ²
Was applied for 6 seconds after welding.

Two pieces of the first member thus obtained and the second member are connected to each other at two non-bonded portions at both ends of the second member.
By bending them one by one on both sides and combining them so as to contact with the first member respectively, a preform of an H-type thermoplastic composite material was manufactured.

The preform thus obtained was bagged with a polyimide film and then heated under pressure at the temperature and pressure shown in the graph of FIG. 4 to obtain a thermoplastic composite material.

Observation of the joint portion between the first member and the second member of the obtained composite material showed that the bent portion of the second member had no wrinkles, sagging, etc., and had voids, resin richness, and carbon fibers. No influx was observed.

[0033]

As described above in detail, in the present invention, the first member formed by laminating and preforming a plurality of composite materials composed of the reinforcing fiber and the thermoplastic resin, the reinforcing fiber and the thermoplastic resin. A plurality of composite materials made of resin are laminated, and a second member formed by partially bonding is used in combination, and a non-bonding portion of the second member is bent to abut the first member, By pressurizing in a temperature range lower than the melting point of the thermoplastic resin, the second member slides to eliminate the deflection and the gap at the contact point, and then heat and apply at a temperature above the melting point of the resin. Since it is pressed and integrally molded, a structural thermoplastic composite material having a good joint between the first member and the second member can be obtained.

The molded thermoplastic composite material of the composite material of the present invention is suitable for structures of various shapes such as L-shaped material, T-shaped material, H-shaped material and I-shaped material.

[Brief description of drawings]

FIG. 1 is a perspective view showing an example of a preform of a molded body of a structural thermoplastic composite material of the present invention.

FIG. 2 is a perspective view showing an example of a second member of the preform of the structural thermoplastic composite material of the present invention.

FIG. 3 is a schematic view showing one step of producing a molded body of the structural thermoplastic composite material of the present invention.

FIG. 4 is a graph showing a heating / pressurizing step in Examples.

FIG. 5 is a plan view showing a molded body of a conventional H-shaped structural thermoplastic composite material.

[Explanation of symbols]

 1 ... Preform 2 ... First member 3 ... Second member 31 ... Material sheet 32 ... Joined part 33 ... Non-bonded part 34 ... Spots 51, 52 , 53 ・ ・ ・ Composite material

Claims (2)

[Claims] 1. A first member formed by laminating and preforming a plurality of composite materials composed of reinforcing fibers and a thermoplastic resin,
The second member is formed by laminating a plurality of composite materials made of reinforcing fibers and a thermoplastic resin, and partially bonding them, and the non-bonding portion of the second member is bent to form the first member. And is heated to a temperature above the melting point of the thermoplastic resin.
A molded body of a thermoplastic composite material, which is integrally molded by being pressed. 2. A first member which is preformed by laminating a plurality of composite materials (A) comprising reinforcing fibers and a thermoplastic resin, and heating and pressing at a temperature not lower than the melting point of the thermoplastic resin. To form a second member by (B) laminating a plurality of composite materials composed of reinforcing fibers and a thermoplastic resin, and partially bonding, (C) non-bonding of the second member It is characterized in that the part is bent and brought into contact with the first member, and (D) is pressed in a temperature range lower than the melting point of the thermoplastic resin, and (E) is then heated and pressed at a temperature higher than the melting point of the thermoplastic resin. And a method for producing a molded body of a thermoplastic composite material.