JPH0227165B2 - - Google Patents

Description

Detailed Description of the Invention This invention is a reinforcement of a fixed height that is adhered to a board, particularly a board material used for car body exterior panels such as automobile door panels and roof panels, and is foam-cured and integrated with the board material. The present invention relates to a method for reinforcing a plate material for forming a section.

Conventionally, as shown in FIG. 1A, B, and C, glass fibers,
It is known that a plate material is reinforced by pasting a thermosetting resin material 4 attached with a reinforcing material 3 such as non-woven fabric, and heating and curing this resin material 4 (Utility Model Publication No. 55-101659). In the figure, 5 is a door inner panel, 6 is a door window sash, 7 is a side window glass, and 8 is an outside door handle.

However, in this conventional example, the desired reinforcing effect cannot be obtained unless the thickness of the resin material 4 is considerably increased, and the amount of resin material used is large, resulting in a correspondingly high production cost and weight. There was a problem that the number of people was also increasing. As another conventional example, it is also known to adhere a reinforcing material that has been molded and hardened in advance to a plate material. However, in this case, it is necessary to mold the reinforcing material so that it perfectly matches the shape of the plate, but such shaping is difficult, and moreover, the plates are usually press-formed, and depending on the conditions of the press process. There has been a problem in that it is very difficult to completely bond both the reinforcing material and the plate due to variations in the amount of spring back of the plate.

Therefore, as shown in FIG.
Automotive plate material in which a reinforcing rib 13 consisting of a thermosetting resin part 11 and a foamed part 12 to which glass fiber or other reinforcing material 10 is added in advance is integrally formed on the inner surface or rust-preventing coating 9, and its We first proposed a manufacturing method (Patent Application No. 114731/1983). According to the proposed invention, all of the above-mentioned conventional problems are solved.

By the way, in order to form this reinforcing rib 13,
A reinforcing material 14 as shown in FIG. 3A is used. This reinforcing material 14 is an uncured resin in which the reinforcing material 10 is added to an unfoamed foamed material 15 (for example, a band-shaped foamed material such as a foamed polyethylene sheet or a foamed epoxy sheet) that foams when heated. The plates 16 (for example, uncured epoxy sheets) are laminated in advance. Then, this reinforcing material 14 is pasted to the part of the plate material 2a that requires reinforcement as shown in FIG. I try to form it tightly at 2a.

However, in order to improve the usability of this reinforcing material 14, it is necessary to form the resin material 16 and the foam material 15 into a sheet shape in advance and then attach them together.
Moreover, in order to form the sheet-like resin material 16 and foam material 15, it is necessary to process the materials and manufacture secondary products, which increases the time and effort required, and as a result, it is difficult to form the reinforcing material 14. This requires a large number of manufacturing steps, and the manufacturing cost of the reinforcing material 14 increases accordingly. Therefore, it has been desired to develop a method for reinforcing the plate material 2a more simply and inexpensively.

This invention was made by focusing on the above points, and involves applying an uncured and unfoamed synthetic resin foam material to the parts of the board that require reinforcement, and then coating the surface of the applied foam material. The purpose of this invention is to solve the above-mentioned problems by covering the board with a material that is difficult to permeate through gas, then foaming and hardening the foam material, and integrally forming a reinforcing part of a predetermined height on the board.

Hereinafter, a method for reinforcing a plate material according to the present invention will be explained based on FIGS. 4 to 6. In the figure, reference numeral 20 denotes a plate material, and a reinforcing portion 21 made of synthetic resin and having a predetermined height H is integrally formed at a portion of the plate material 20 that requires reinforcement. In this case, a longitudinal portion of the plate material 20 is selected as a portion of the plate material 20 that requires reinforcement, and a reinforcing portion 21 with a width W and a length L is formed therein, but this is particularly limited to this example. Not a thing,
For example, although not shown, the reinforcing portion 21 may be formed across the horizontal direction of the plate material 20, may be formed in a shape that intersects the vertical direction and the horizontal direction, or may be formed to intersect diagonally. Furthermore, it may be formed on the entire surface of the plate material 20.

In order to form the reinforcing portion 21, first, a synthetic resin foam material 22 is applied to the portion of the plate material 20 that requires reinforcement. As the foaming material 22, any material that foams at room temperature or material that foams when heated can be used, and for example, foamed epoxy resin material, foamed urethane resin material, foamed polyethylene resin material, etc. can be selected. In addition to these foam materials, there are also uncured so-called thermosetting materials that are lightweight, expand in volume at an appropriate rate, are suitable for coating, can retain their shape to some extent after coating, and have a certain degree of rigidity after foaming and curing. Any B-stage foam material commonly used in resins can be used, and it does not particularly matter whether it is closed cell or open cell. When a foamed epoxy resin material is used as the foamed material 22, its composition may include, for example, Epicoat #1004 (manufactured by Yuka Ciel Co., Ltd.), which is a bisphenol A type epoxy resin material,
Hiker is a nitrile rubber containing carboxyl groups.
A B-stage product is preferable, which is an epoxy resin composition made by adding CTBN (manufactured by BF Gutudoritsu) and a dicyandiamide curing agent, and adding, for example, Vinyhole AK #2 (manufactured by Eiwa Kasei Co., Ltd.) as a foaming agent. . The foam material 22 can be applied by brush application, spray application with a spray gun, or other means, but since a thick layer can be obtained with one application, pressure is applied to the foam material 22 itself, and a special nozzle is applied to the foam material 22. Airless spray, which atomizes the atomization, is optimal. In addition, 23 in the figure is a spray gun for airless spray.

Next, by applying this unfoamed foam material 22, a foam layer 24 having a certain thickness t is formed at a portion of the plate material 20 that requires reinforcement. The thickness t of this foam layer 24 needs to be sufficient to foam and obtain the height H of the reinforcing portion 21 .

Furthermore, after forming the foam layer 24 with a constant thickness t in the portions of the plate material 20 that require reinforcement as described above, the foam layer 24 is
A degassing prevention material 26 as a "member that is difficult for gas to permeate" is attached to the surface 25 of the foam layer 24, and then the foam layer 24 is foamed and hardened at room temperature or by heat treatment. For example, when the plate material 20 is an automobile door outer panel, heat treatment can be carried out in a drying oven in the car body painting process, specifically in the ED (undercoating) painting process, intermediate coating painting process, or top coating painting process. A furnace can be used, and the foam layer 24 together with the door outer panel may be heat-treated in such a drying furnace to foam and harden. In addition, the reason why the gas release prevention material 24 was attached to the surface 25 of the foam layer 24 prior to the foaming is to improve the foaming ratio of the foam layer 24 and increase the height.
As the gas release prevention material 26, for example, kraft paper or the like can be used.

Then, by foaming and curing the foam layer 24, a reinforcing portion 21 having a predetermined height H is integrally formed at a portion of the plate material 20 that requires reinforcement, and as a result, the plate material 20 is reliably reinforced. Although not shown, a structural resin material may be further applied to the foamed reinforcing portion 21 and the plate material 20 in its vicinity and hardened. Epoxy resin materials and others can be used as the structural resin material. In this way, the periphery of the reinforcing part 21 is covered with resin, so even if water adheres to it, it will not infiltrate into the inside.
It does not accumulate for a long time and therefore does not corrode the plate material. Further, especially when the reinforcing portion 21 requires strength, it is preferable to attach glass cloth or the like after forming the foam layer 24.

Next, a test example is shown.

First test example Plate material 20: Steel plate test piece (80mm x 200mm x 0.7mm
t) Foamed material 22: Foamed epoxy resin material Structural resin material: Epoxy structural adhesive (Sumitomo
3M#2214) A foamed epoxy resin material was applied to the entire surface of one side of the above steel plate test piece to form a foamed layer with a thickness of 0.5mm.After attaching kraft paper to this, it was heated at 140℃ for 30 minutes. After curing the foam and applying 0.2mm thick epoxy structural adhesive on top of it, it was heated at 140℃ x 30cm.
When the steel plate was heat-treated for several minutes and hardened, a reinforcing portion with an average height of 3.5 mm could be easily formed on the entire surface of one side of the steel plate test. Bending this with a span of 100mm and a bending speed of 5
When a bending test was performed at a rate of mm/min, at least the results shown in FIG. 7 were obtained. In Figure 7, A indicates the test value when only the steel plate test piece is used,
B shows the test value of the steel plate test piece provided with the reinforcement part.
As can be seen, the maximum load of the steel plate specimen alone is 10 kg and the bending rigidity is approximately 2.7 kg/mm, while the steel plate specimen with reinforcement has a maximum load of 55 kg/mm.
Kg, bending rigidity is 30Kg/mm, and the maximum load and bending rigidity are much improved.

2nd test example Select the same material as in the 1st test example, apply foamed epoxy resin material to one side of the steel plate test piece with a width of 15mm to form a 0.5mm thick foamed layer, and attach kraft paper to this. Then, heat treatment was performed at 140°C for 30 minutes to foam and harden the specimen, and then 0.2 mm thick epoxy structural adhesive was applied to the entire surface of the steel plate specimen, and heat treated at 140°C for 30 minutes to harden it. A bead-shaped reinforcement with a height of 3.5 mm could be easily formed on one side of the steel plate specimen. When this was subjected to a bending test in the same manner as in the first test example, at least the results shown in FIG. 8 were obtained. If A in the figure is only a steel plate test piece,
B′ is the test value for a steel plate specimen with a reinforcement part, the maximum load of the steel plate specimen with this reinforcement part is 38Kg, and the bending rigidity is 17Kg/mm, which is much higher than the case of only a steel plate specimen. has improved.

Third test example Plate 20: Steel plate test piece (40mm x 300mm x 0.8mm
t) Foamed material 22: Two-component mixable foamed urethane resin material A foamed urethane resin material with a urethane density of 0.05 g/cm ³ and a foamed urethane resin material with a urethane density of 0.1 g/cm ³ are made with different thicknesses. It was applied to each of three steel plate test pieces to form foam layers with different thicknesses,
After attaching kraft paper to this, each foam layer was foamed and hardened at room temperature to form six types of steel plate test pieces each having a reinforcing portion with a height of 5 mm, 10 mm, and 20 mm. When bending tests were conducted on these six types of steel plate test pieces, at least the results shown in FIG. 9 were obtained. C in the diagram is urethane density
Point E shows the case where a foamed urethane resin material with a density of 0.05 g/cm ³ is used, D shows the case where a foamed urethane resin material with a urethane density of 0.1 g/cm ³ is used, and point E shows the case where only the steel plate test piece is used. . As can be seen from this, in both cases C and D, the maximum load is improved compared to E. Of course, the bending rigidity is also improved. Moreover, from FIG. 9, it was found that the higher the urethane density and the higher the height of the reinforcing portion, the greater the maximum load. Therefore, if the urethane density is to some extent high and the reinforcing part is formed with a certain height, the plate material 2 can be easily and reliably strengthened.
This makes it possible to improve the maximum load of 0 and bending steel properties.

In the first to third test examples, since kraft paper was attached to the foam layer and foamed, a higher foaming rate was obtained than when kraft paper was not attached. In other words, if you attach kraft paper and foam it, even if the foam layer is the same height when applied, the height of the reinforcing part after foam hardening can be increased, and the maximum load and bending rigidity will be increased accordingly. This is something that can be done.

As explained above, according to this invention,
The structure is such that the surface of the foamed material made of uncured and unfoamed synthetic resin is covered with a material that is difficult for gas permeation to the plate-like reinforcement required area, and then the foamed material is foamed and hardened. Since it was decided to integrally form a reinforcing portion with a predetermined height on the top, it was necessary to prepare an uncured sheet-like resin material and an unfoamed sheet-like foam material by forming them in advance and laminating and attaching them. Instead, if the foam material is applied directly to the plate material, covered with a material that is difficult for gas to permeate, and then foamed, it is possible to easily and reliably form a reinforcing part that is integrated with the plate material. The effort and labor required for forming the resin material and the unfoamed sheet-like foam material can be reduced, and the manufacturing cost can be reduced accordingly. Of course, since the reinforcing portion is made of foam, it is light in weight, and since the foam material is applied to the plate material by coating, it has the advantage that it can be attached regardless of the shape of the plate material. Therefore, it is more effective when reinforcing the outer panel of an automobile that has relatively few flat surfaces and that requires energy saving and weight reduction of even 1 g.

[Brief explanation of drawings]

1A is a front explanatory view of a conventional door; FIG. Figure A is a perspective explanatory view of the main parts of the door outer panel that has already been proposed as a solution to the problem of the conventional example, Figure 3 is a sectional view taken along the - line of Figure 2 A, and Figure 3 A and B are the same as Figure 2 B. Figure 3A shows the reinforcing material before it is attached to the plate material, Figure 3B shows each cross-sectional view after it is attached to the plate material, and Figure 4 is an embodiment of the present invention. FIG. 5 is an enlarged sectional view taken along the line V-V in FIG. FIG. 8 is a characteristic diagram showing the results of the second test example, and FIG. 9 is a characteristic diagram showing the results of the third test example. 20... Plate material, 21... Reinforcement part, 22... Foamed material, 24... Foamed layer, H... Constant height.

Claims (1)

[Claims] 1. Apply an uncured and unfoamed synthetic resin foam material to the parts of the board that require reinforcement, then cover the surface of the applied foam material with a material that is difficult for gas to pass through, and then foam the foam material. A method for reinforcing a plate material, which comprises curing the plate material and integrally forming a reinforcing portion of a predetermined height on the plate material.