JPH0524833B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a fiber-reinforced resin molded product used as a bathtub, water container, etc., and a method for manufacturing the same.

(Prior Art) Resin molded products used for bathtubs and the like are required to have watertightness, heat resistance, and the like. Conventionally, this type of resin molded product has been made using reinforcing fibers such as glass fibers and carbon fibers of 25 to 50 mm (1 to 2 inches).
Generally, a gel coat was formed on the surface of a laminate mixed with a thermosetting reinforcing resin for a certain length. In such molded products, if air bubbles with a diameter of 1 mm or more are present between the laminate or between the gel coat and the laminate, the gel coat will be destroyed by repeated application of high and low temperatures, such as in a bathtub. If the gel coat is destroyed, it will not only become unsightly due to the adhesion of dirt, but also cause water leakage. For this reason, harmful air bubbles must be removed from the laminate or between the laminate and the gel coat in resin molded products used for bathtubs and the like.

The method for forming a laminate of fiber reinforced resin is as follows:
A spray-up method is known that can be carried out using relatively simple equipment. In the spray-up method, reinforcing fibers of a predetermined length (approximately 25 to 50 mm) are sprayed onto a mold together with atomized thermosetting reinforcing resin to form a laminate. Conventionally, various methods have been developed for removing harmful air bubbles when forming a laminate by a spray-up method. For example, Tokko Akira
Publication No. 59-35765 discloses that a laminate is formed by spraying a resin together with reinforcing fibers into a mold under reduced pressure, and then a cell surface layer is formed on the laminate and the cells are collapsed by being exposed to atmospheric pressure. A method is disclosed. Further, Japanese Patent Application Laid-open No. 124237/1983 discloses a method in which a laminate is formed by spraying a resin together with reinforcing fibers into a mold, and then an airtight surface layer is formed on the laminate and pressurized. In either method, it is necessary to form an airtight surface layer made of resin, and since the surface layer does not contain reinforcing fibers, the strength of the molded product is reduced. There is also a risk that cracks may occur in the surface layer during curing. In the method disclosed in JP-A-60-124237, the molded product must be cured in a pressurized tank until it is completely cured, and the molded product is not pressurized. The tank is occupied for a long time, which reduces productivity and is not economical. Since the length of the reinforcing fibers is also 25 to 50 mm, large bubbles are likely to occur. Air bubbles are particularly likely to occur in the corners of molded products, making defoaming work difficult. For this reason, defoaming defects are likely to occur, resulting in variations in quality.

(Problems to be Solved by the Invention) The present invention solves the above-mentioned conventional problems, and its purpose is to eliminate the presence of toxic air bubbles in the laminate, and thus to make it watertight, such as in bathtubs. The object of the present invention is to provide a fiber-reinforced resin molded product suitable for use in articles that require high strength and heat resistance. Another object of the present invention is to provide a method for manufacturing a fiber-reinforced resin molded product, which allows for extremely easy defoaming work and improves productivity.

(Means for Solving the Problems) The fiber-reinforced resin molded product of the present invention comprises a first laminate made of relatively short reinforcing fibers and a thermosetting resin, and a first laminate made of relatively long reinforcing fibers and a thermosetting resin. The above object is achieved by comprising a second laminate and a gel coat on the surface of the first laminate, and by interposing the bubble-free first laminate between the gel coat layer and the second laminate.

The method for manufacturing fiber-reinforced resin molded products of the present invention is a method for manufacturing fiber-reinforced resin molded products by spray-up molding, in which relatively short reinforcing fibers and thermosetting resin are sprayed onto a mold. forming a second laminate by spraying the first laminate with relatively long reinforcing fibers and a thermosetting resin before the first laminate is cured; curing the first and second laminates, thereby achieving the above object.

(Example) Examples of the present invention will be described below.

As shown in FIG. 1, the fiber-reinforced resin molded product of the present invention includes a first laminate 11 made of relatively short reinforcing fibers 11a and a thermosetting resin 11b;
Relatively long reinforcing fiber 12a and thermosetting resin 1
2b. A gel coat 13 as a top coat is formed on the surface of the first laminate 11.

Reinforcing fiber 1 contained in first laminate 11
The length of 1a is in the range of 2.0 to 10.0 mm, preferably
It is said to be in the range of 3.0 to 6.0 mm. Further, the first laminate 11 has a thickness of 0.6 to 1.25 mm.

The length of the reinforcing fibers contained in the second laminate 12 is in the range of 25 to 50 mm.

Reinforcing fiber 1 contained in first laminate 11
1a is short compared to the reinforcing fiber length of 25 to 50 mm (1 to 2 inches) contained in conventional laminates, and although the mechanical strength of the laminate 11 is slightly reduced, it is compatible with the resin, The voids and bubbles caused by entanglements such as bridges between fibers become smaller and fewer. In conventional laminates in which the length of reinforcing fibers is 25 to 50 mm, bubbles with a diameter of about 2.0 to 3.0 mm are generated, whereas when the length of reinforcing fibers is about 10 mm as in the present invention, bubbles with a diameter of about 1.0 mm are generated. ~1.5mm
Some air bubbles were generated, and the length of the reinforcing fiber was 6 mm.
Below that, only extremely small bubbles with a diameter of 0.5 to 1.0 mm will be generated. The mechanical strength of the laminate is determined by the length of the reinforcing fibers being approximately 10 mm.
of conventional laminates with reinforcing fiber length of 25-50mm.
It has a strength of 80-90%, but the length of reinforcing fiber is 6
If it is less than 2 mm, the strength will be halved, and if it is less than 2 mm, cracks due to curing shrinkage can be prevented, but the reinforcing effect will hardly be exhibited. Furthermore, if the length of the reinforcing fibers is less than 2 mm, it is difficult to cut and spray the fibers using a spray up machine. For this reason, it is desirable that the reinforcing fibers contained in the first laminate 11 be 2 mm or more.

In a laminate with reinforcing fibers about 10 mm in length, air bubbles with a diameter of 1.0 to 1.5 mm are generated;
Since harmful air bubbles larger than mm are generated, defoaming work is required. Again, the bubble diameter is up to 1.5
Since it is about mm, degassing work is easy. However, in laminates with reinforcing fibers of 6 mm or less, the bubble diameter is as small as 1.0 mm or less, and no harmful bubbles are generated, so defoaming is not necessary. If you roll the roller onto the laminate as much as possible,
(The entire laminate moves as the roller moves, making defoaming impossible.)

Reinforcing fibers 11a in first laminate 11
The content is 25 to 30% by weight, preferably about 28% by weight, based on 100% by weight of the laminate. If the reinforcing fiber content is within this range, there is no fear that the resin will float on the laminate surface and the reinforcing fibers will be exposed on the surface.

If the thickness of the first laminate 11 is less than 0.6 mm, the laminate itself cannot serve as a reinforcing layer.
If it is 1.25 mm or more, the reinforcing fibers are too short and there is a risk of dripping during molding. Also, 0.6
If it is less than mm, the air bubbles generated in the second laminate become the first laminate.
If it breaks through the laminate and invades the boundary with the gel coat, and if the thickness exceeds 1.25 mm, the second laminate becomes thinner by that much, and the bending strength of the molded product becomes weaker. For this reason, a range of 0.6 mm to 1.25 mm is preferable.

Reinforcing fibers 1 contained in second laminate 12
The length of 2a is about 25 to 50 mm, similar to the reinforcing fibers contained in conventional laminates. For this reason, harmful air bubbles with a diameter of 1 mm or more are generated, but such air bubbles do not float to the surface due to the presence of the first laminate 11 and do not destroy the gel coat 13. In addition, the laminate 12
It doesn't reduce your strength either.

As reinforcing fibers in each laminate 11 and 12, glass fibers, carbon fibers, aramid fibers, etc. are used. Further, as the thermosetting resin, unsaturated polyester resin, epoxy resin, phenol resin, etc. are used similarly to the gel coat.

Such a fiber-reinforced resin molded article of the present invention,
For example, it is manufactured using a molding apparatus shown in FIG.
The molding apparatus has a mold 22 disposed on a turntable 21 and two spray up machines 30 and 40. On the other hand, spray up machine 3
0 is a resin spraying machine 31 that sprays a thermosetting resin such as unsaturated polyester, and a fiber spraying machine that cuts a continuous fiber strip 33 of glass or the like into a predetermined length (2 to 10 mm) and sprays it as short fibers. 32. The other spray-up machine 40 includes a resin sprayer 41 that sprays the same resin as that sprayed by the spray-up machine 30, and a resin sprayer 43 that cuts continuous fibers 43, such as glass, into a predetermined length (25 to 50 mm) and produces long fibers. It has a fiber spraying machine 42 that sprays the fibers as a fiber sprayer. A resin supply pipe 34 and a hardening agent supply pipe 35 are attached to the resin spraying machine 31. The resin supply pipe 34 supplies a predetermined thermosetting resin to the spraying machine 31, and the hardening agent supply pipe 35 supplies a hardening agent. It is supplied to the sprayer 31.
A similar resin supply pipe 44 and hardening agent supply pipe 45 are also attached to the other sprayer 41.

A fiber-reinforced resin molded product using the molding apparatus having such a configuration is manufactured as follows. First, a gel coat is formed in advance on the mold 22 on the turntable 21. If the molded article does not require a gel coat, forming a gel coat on the mold 22 is unnecessary. Next, the thermosetting resin mixed with a curing agent is sprayed onto the mold 22 from the resin sprayer 31 of one of the spray-up machines 30, and the fiber sprayer 32 is used to spray short pieces of predetermined length in the range of 2 to 10 mm. The fibers are sprayed to form a first laminate. While the laminate is uncured, spray up machine 40
A thermosetting resin mixed with a curing agent is sprayed onto the first laminate from a resin spraying machine 41, and
A second laminate is formed by spraying long fibers with a predetermined length in the range of 25 to 50 mm from the fiber spraying machine 42. If the short fiber length is 6 mm or more (10 mm or less), the second laminate is applied while both laminates are uncured.
A roller is rolled onto the laminate surface with a predetermined pressure. As a result, air bubbles generated within the first laminate are defoamed. This defoaming operation can be easily performed because the size of the bubbles is smaller than the size of bubbles in conventional laminates. When the short fiber length is 6 mm or less, the diameter of the bubbles generated in the first laminate is usually 1 mm or less,
Deaeration work using rollers is not necessary. and,
A second laminate is formed, and after defoaming, the first and second laminates are cured to obtain a molded product in a predetermined shape in which both laminates are integrated.

(Effects of the Invention) As described above, since the present invention has the first laminate in which there are almost no harmful air bubbles,
There is no risk of damage to the gel coat, it has excellent watertightness and heat resistance, and even when used in environments with rapid temperature changes such as bathtubs, it does not damage its appearance and has a long lifespan.

According to the manufacturing method of the present invention, defoaming is extremely easy or unnecessary, molded products with excellent watertightness and heat resistance can be easily obtained, and productivity is improved.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an example of a fiber-reinforced resin molded product of the present invention, and FIG. 2 is a schematic diagram of an apparatus for manufacturing the molded product. 11... first laminate, 11a... reinforcing fiber,
11b...Thermosetting resin, 12...Second laminate, 12a...Reinforcing fiber, 12b...Thermosetting resin,
22... Molding mold, 30, 40... Spray up machine.

Claims (1)

[Scope of Claims] 1. A first laminate with a thickness of 0.6 to 1.25 mm consisting of relatively short reinforcing fibers with a length of 1.2 to 10 mm and a thermosetting resin, and a comparison with a length of 25 to 50 mm. a second laminate comprising long reinforcing fibers and thermoset resin;
A fiber-reinforced resin molded product that is installed between the gel coat and the gel coat.