JPS595425B2 - Manufacturing method of sanderch structure cylinder - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method that simplifies the production of a sandwich-structured cylindrical body that has no joints on the peripheral wall and has excellent strength, appearance, etc., and eliminates waste of work space, materials, etc. be.

The following method is generally used as a conventional method for manufacturing a sandwich structure cylinder.

That is, a sandwich structure plate of a desired size is prepared, several slits are provided on one side of the plate, the slits are bent, and the ends of the plate are joined together to form an appropriate shape. The method was the same as that used for manufacturing so-called folding boxes, which are used to manufacture sandwich-structured cylindrical bodies.

However, this conventional method has the following drawbacks.

(1) Two steps are required: a step of making a sandwich structure plate and a step of making a cylinder using the plate. (2) It is necessary to prepare a sandwich structure plate having the size of the unfolded shape of the cylinder to be manufactured, and since this plate is placed while working, the work area becomes inevitably large. (3) This sandwich structure cylinder has at least one joint, and special measures are required to provide sufficient strength to the joint.

In addition, the slit portion provided for bending is weak in strength and therefore requires rework.

The present invention is an invention aimed at solving the above-mentioned problems, and its gist is that a mold release treatment is applied to the inner surface of a female mold having a desired cylindrical inner surface, and this surface is uncured. The fiber-reinforced plastics are laminated to form an outer layer, and then, before the outer layer hardens, a core material of a predetermined thickness is pressed against the outer layer, and as the outer layer hardens, the core material is bonded to the outer layer. After this, an uncured fiber-reinforced plastic is further laminated on the core material to form an inner layer, and the inner layer is dried and cured to produce a sandwich structure. An example of implementing the present invention will be described below with reference to the drawings.

FIG. 1 is a cross-sectional view schematically showing the configuration of a sandwich structure cylinder, and FIG. 2 is a partially cutaway front view of a tank using the cylinder.

In Fig. 1, the female mold used for molding is only shown schematically with chain lines, but its inner surface is a mold that is adapted to the external shape of the desired cylinder. do.

First, a mold release agent (not shown) is applied to the inner surface of the female mold M.

This is used to facilitate the mold release operation of molded products, and contains waxes with high melting points, higher fatty acids and their salts and esters, silicone oil, polyvinyl alcohol, low molecular weight polyethylene, derivatives of vegetable proteins, etc. used. A gel coat resin is applied to the surface coated with the mold release agent to form a gel coat layer 1. When water resistance and chemical resistance are required for this gel coat resin, isophthalic acid-based polyester resin or the like is used. When the gel coat resin applied in this way is dry to the touch, an uncured fiber-reinforced plastic is laminated and adhered to the resin surface to form the outer layer 2.
form. Immediately after this lamination work is completed, a core material 3 made of urethane foam or the like is bonded to the same surface using a suitable fixture. In this case, it is preferable to use core material 3 whose ends are rounded in advance to match the roundness of the corners of female mold M. next,
The outer layer 2 is cured and the core material 3 is adhered to the outer layer 2. When the adhesion of the core material 3 is completed, the fixing device is removed, and uncured fiber reinforced plastic is laminated and bonded to form the inner layer 4. If a top coat layer 5 is further provided on the inner surface layer according to the requirements and dried and cured, a sanderch structure cylinder is formed from the above-mentioned layers.

The top coat resin forming the top coat layer 5 is an isophthalic acid or bisphenol polyester resin when water resistance and chemical resistance are required. Once curing is complete, the mold is released and unnecessary burrs are removed to create a finished product.

This cylindrical body is used for various purposes such as a tank T as shown in FIG. Note that although a rectangular cylinder is shown in the figure, a circular cylinder is of course also possible.

As described above, according to the method of the present invention, (a) since integral molding is performed using a female mold, a sanderch structure cylinder having no joints, uniform strength, and good dimensional accuracy can be obtained, and the mold can be released on the inner surface of the female mold. After treatment, an uncured fiber-reinforced plastic is laminated on this surface to form an outer layer, resulting in a sanderch structure cylinder with a smooth outer surface and a beautiful appearance.

(b) Before the outer layer is cured, a core material of a predetermined thickness is pressed against the outer layer, and as the outer layer hardens, the core material is bonded to the outer layer. Therefore, when bonding the core material to the outer layer, a separate Not only does it not require an adhesive, but the process of forming the outer layer and adhering the core material are completed while the outer layer is being cured, so manufacturing can be done in a short time. (c) Manufacture a sanderch structural cylinder with uniform strength in a single process, without requiring the conventional two-step process of making a sanderch structural plate and bending the plate to form a cylinder. Can be a workshop,
It is possible to eliminate waste of materials, etc. (d) Even though the cylinder has a sandwich structure, a rectangular cylinder with sharp corners can be obtained. There are various advantages such as

[Brief explanation of drawings]

The figures show an example of the implementation of the present invention.
The figure is a partially cutaway front view of a tank using the cylindrical body. M is female type, 1 is gel coat layer, 2 is outer layer, 3 is heartwood,
4 is an inner layer, and 5 is a top coat layer.

Claims (1)

[Claims] 1. The inner surface of a female mold having a desired cylindrical inner surface is subjected to a mold release treatment, and an uncured fiber-reinforced plastic is laminated on this surface to form an outer layer, and then a predetermined layer is formed before the outer layer is cured. After the core material of the same thickness is pressed against the outer layer and the outer layer is cured to bond the core material to the outer layer, an uncured fiber-reinforced plastic is further laminated on the core material to form an inner layer. A method of manufacturing a sandwich structure cylinder by drying and curing.