JPH0369317A - Manufacture of sandwich structural body - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention relates to a method for manufacturing a sandwich structure in which a core material is sandwiched between skin materials, and more specifically, the present invention relates to a method of manufacturing a sandwich structure in which a core material is sandwiched between skin materials, and more particularly,
The present invention relates to a method for manufacturing a sandwich structure using I-reinforced resin (FRP) and non-foamed FRP as a skin material.

(Prior Art) Conventionally, in order to manufacture this type of sandwich structure, a core material and a skin material are molded separately and the two are combined, as seen in, for example, Japanese Patent Laid-Open No. 81-158446. The main methods used have been to polymerize and integrate with an adhesive, or to sandwich a separately molded core material between FRP prepreg skin materials and heat-cure them to integrate.

(Problems to be Solved by the Invention) However, according to the above method of integrating with adhesive, in addition to the step of molding the core material and the skin material independently,
It requires a bonding process that includes multiple processes such as pretreatment, adhesive curing, and curing, which inevitably increases costs.Furthermore, it is difficult to ensure strength and stability due to the difficulty of bonding itself. There was a problem that. In addition, according to the above-mentioned method of integrating by heat curing, the process can be shortened by eliminating the need for the molding process of the skin material, but the process of molding the core material still remains, and furthermore, the bonding between the core material and the skin material may be poor. There was also the problem of a lack of a decisive factor.

The present invention was made to solve the above-mentioned conventional problems, and its purpose is to significantly shorten the process, contribute to cost reduction, and at the same time, stably improve bonding strength. An object of the present invention is to provide a method for manufacturing a sand inch structure.

(Means for Solving the Problems) In order to achieve the above object, the present invention impregnates a first base material with a low Fa fiber density with an uncured resin containing a blowing agent and a relatively small amount of catalyst. Together with Takasen! A second base material having a high density is impregnated with an uncured resin containing a relatively large amount of catalyst without the addition of a blowing agent, and then the second base material is placed on both the upper and lower surfaces of the first base material. In the present invention, which is characterized in that it is configured to be supplied to a mold and foamed and hardened within the mold, the type of fiber constituting the base material is not limited, and glass fiber, carbon mi, aramid m fiber, etc. etc. can be selected. The base material is made by accumulating these fibers at low density or high density. For example, a nonwoven fabric such as a continuous strand mat is used as the first base material with low m fiber density, and the first base material with high #a fiber density is used as the base material. As the base material 2, for example, a nonwoven fabric or woven fabric (cloth) such as chopped strand mat can be used. A multilayer knitted fabric can also be used. In this case, if the low-density middle layer is used as the first base material and the high-density surface layer is used as the second base material, the first and second layers can be used. There is no need to prepare a separate base material.

Further, in the present invention, the type of resin with which the base material is impregnated is not limited, and for example, polyurethane resin, epoxy resin, etc. can be selected. Further, the types of blowing agents and catalysts added to these resins are also optional. For example, Freon can be used as the blowing agent, and dimethylethanolamine can be used as the catalyst.

(Function) In the method for manufacturing the sandwich structure configured as described above, the reaction is accelerated as the amount of catalyst added increases, so first the resin in the second base layer placed on the surface hardens, and then The resin in the first base layer placed in the middle foams and hardens.
The core material made of foamed FRP and the skin material made of thermally foamed FRP are integrally molded.

(Example) Hereinafter, an example of the present invention will be described based on the accompanying drawings.

1 to 4 show a first embodiment of the present invention.In the first embodiment, first, as shown in FIG. Prepare a thin cloth (base material 1) 1 and a thin cloth (second base material) 2, apply polyurethane resin B liquid described below to the continuous strand mat L, and polyurethane resin A liquid described below to the cloth 2. Impregnate each. Impregnation with the resin liquid is carried out in the manner of hand lay-up, and after the resin liquid is attached to the base materials 1 and 2 by coating or dipping, the base materials 1 and 2 are pressed with a roller 5, for example, as shown in FIG. and allow the resin liquid to penetrate into the inside. At this time, the roller 5 is particularly strongly pressed against the continuous stranod mat 1 to sufficiently squeeze out the excess resin liquid. Through this operation, inside the continuous strand mat 1, as shown in FIG. begins to form.

An example of the composition of the polyurethane resin liquid A and polyurethane resin liquid B is shown in the table below.

In other words, the polyurethane resin B liquid contains Freon, which is a blowing agent, whereas the polyurethane resin A liquid contains no blowing agent at all, and the catalyst that accelerates the curing reaction is more Polyurethane resin liquid A also contains more.

Next, as shown in FIG. 1, a cloth 2 impregnated with polyurethane resin A liquid is placed on both upper and lower surfaces of the continuous strut mat 1 impregnated with the polyurethane resin liquid B, and this is supplied to a mold. The mold is heated to a predetermined temperature in advance, and when the mold is closed, the polyurethane resin liquid A in the cloth 2 containing a relatively large amount of catalyst is first hardened.
Subsequently, the polyurethane resin liquid B in the continuous strand mat 1 is foamed and hardened. Since the continuous strand mat 1 has its upper and lower surfaces pressed by the previously cured cloth 2, the foam formed by the foaming of the liquid B fills the void 1b (FIG. 3) in the base. As a result, as shown in FIG. 4, the core material 6 made of foamed FRP and the skin materials 7 made of non-foamed FRP are integrally molded, and then, if cured at a predetermined temperature and time,
A monolithic sandwich structure 8 is now obtained.

In addition, according to this embodiment, when the polyurethane resin liquid A that has been impregnated into the cloth 2 is cured, heat is generated, so that the continuous strand mat (first base material) 1 is The curing of the polyurethane resin B liquid impregnated with the mold is accelerated, and therefore there is no need to keep the mold temperature so high.

5 to 8 show a second embodiment of the present invention. In the second embodiment, as shown in FIG.
A double knitted fabric 11 is prepared, and the above-mentioned urethane resin liquid B is first applied to it by coating or dipping, and then, as shown in FIG. 6, the double knitted fabric 11 is
The double knitted fabric 11 is strongly pressed to squeeze out the excess urethane resin B@15.The upper layer 12 and lower layer 13 have a high fiber density, and the middle layer 14 has a low fiber density. Also for the layer, as shown in Figure 7, the fiber 1
Polyurethane resins 1 & 15 adhere only around 111a, and many voids 11b are formed.

Next, as shown in FIG. 8, the upper and lower layers 12 and 13 of the double knitted fabric 11 impregnated with the polyurethane resin B solution as described above are sprayed with the polyurethane resin A solution 16 using the spray nozzle 18. Spray to the specified thickness. As a result of this spraying, a portion of the polyurethane liquid A 16 enters into the gaps tb in the upper and lower layers 12 and 13 of the double knitted fabric H, filling most of the gaps ttb. After that, this is supplied to the mold and molded into the mold r1. Then, first, the polyurethane resin liquid A in the upper and lower layers 12 and 13 containing a relatively large amount of catalyst hardens, and then the polyurethane resin liquid B in the intermediate layer 14 foams and hardens, and a part of it is already hardened. Upper, lower layer 1
2, invaded the void in 13.

As in the first embodiment, the core material 6 made of foamed FRP and the skin material 7.7 made of non-foamed FRP are integrally molded (FIG. 4).

According to the second embodiment, in particular, since the double weight fabric 11 is used as the base material, the upper and lower M12.13 with high m fiber density have a low m! The intermediate layer 14 of I density serves as a first base material, and the skin material 7 is integrally molded to correspond to the upper and lower layers 12 and 13, and the core material 6 is integrally molded to correspond to the intermediate layer 14. It becomes 2. Therefore, unlike the first embodiment, there is no need to separately prepare two base materials (continuous strand mat 1 and cloth 2), and productivity is further improved.

In the second embodiment, the polyurethane resin A liquid was sprayed onto the double knitted fabric 11 impregnated with the polyurethane liquid B using the spray nozzle 18, but instead of this, for example, as shown in FIG. A polyurethane resin liquid A 18 is applied in advance to a heat-resistant film 18 with good mold releasability, and this is applied to the double la base 11 to coat the upper and lower resin layers 12.
In this case, the film 18 can be foamed and cured in a mold together with the film 18, and then the film 1B can be peeled off. This makes it easy to use, and it also makes it possible to prevent contamination of the mold with resin.

In addition, in each of the above examples, polyurethane resin was used as the resin to be impregnated into the base material. If resins with excellent properties such as these are used, it becomes possible to apply them to automobile exterior panels and the like.

(Effects of the Invention) As described above in detail, according to the method for manufacturing a sandwich structure according to the present invention, the core material and the skin material can be integrally molded, and productivity is significantly improved. Effects can be obtained. In addition, integral molding ensures perfect bonding between the core material and the skin material, resulting in the effect of ensuring stable bonding strength.

[Brief explanation of drawings]

1 to 4 show a first embodiment of the present invention, and FIG. 1 is a perspective view showing the basic steps. FIG. 2 is a side view showing the resin impregnation process, FIG. 3 is a sectional view showing the state of the base material after resin impregnation, and FIG. 4 is a perspective view of the sandwich structure obtained by the method of the present invention. , 5th
9 to 9 show a second embodiment of the present invention, FIG. 5 is a perspective view showing a double knitted fabric as a base material, and FIG. 6 is a side view showing the primary step of resin impregnation. , FIG. 7 is a cross-sectional view showing the state of the base material after resin impregnation, FIG. 8 is a side view showing the secondary process of resin impregnation, and FIG. 9 is a cross-sectional view showing the state of the base material after resin impregnation. FIG. 3 is a side view showing a secondary step of impregnation. l...Continuous strand mat (first base material) 2...Cross (second base material) 3.15,1θ...Resin liquid 6...Core material 7...Skin material 11... Double knitted fabric 12, 13... Upper/lower layer (second base material) 14
... Intermediate layer (first base material) Figure 5 Figure 2 Figure 3

Claims (1)

[Claims] (1) A first base material with a low fiber density is impregnated with an uncured resin containing a blowing agent and a relatively small amount of catalyst, and a second base material with a high fiber density is impregnated without the addition of a blowing agent. Impregnating an uncured resin containing a relatively large amount of catalyst, then supplying the second base material to the upper and lower surfaces of the first base material to a mold, and foaming and curing in the mold. A method for manufacturing a featured sandwich structure.