JP2002036264A - Double-layered molded article and method for manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lightweight double-layered molded article excellent in productivity and recycleability, and a method for manufacturing the same. SOLUTION: The double-layered molded article is constituted of a surface layer, which is formed by spraying a urethane resin composition along the molding surface of a mold to mold the same into the shape conforming to the molding surface and curing the molded composition, and a foamed reinforcing layer, which is formed by spraying a foamable urethane resin composition on the back surface of the surface layer and foaming and curing the same so as to conform to the shape of the back surface of the surface layer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multilayer molded product used for, for example, an exterior part of an automobile called an aero part, and a method of manufacturing the same.

[0002]

2. Description of the Related Art As shown in FIG. 8, there is an automobile 100 in which an exterior part 200 called a skirt-shaped aero part is attached below a bumper 101 or the like in order to reduce air resistance during traveling. Exterior parts such as this type of aero parts have conventionally been made of fiber reinforced plastic (FRP) using a hand lay-up method or a spray-up method.

[0003] However, when the above-mentioned exterior parts are molded using fiber-reinforced plastic, it takes a long time for the resin to harden. Must be prepared, which increases the manufacturing cost. In the case of fiber-reinforced plastics, since the glass fibers are dispersed, there is a problem in recyclability, and there is also a problem in weight.

On the other hand, a method of molding by press molding or injection molding is also conceivable. However, in the case of molded products such as the aero parts described above, since a large variety of small-quantity products are produced, the production cost is increased when press molding or injection molding is performed. Therefore, there is a problem in that a large number of molds having a high manufacturing cost must be prepared, thereby increasing the manufacturing cost.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a lightweight multi-layer molded product excellent in productivity and recyclability and a method for producing the same in view of the above circumstances.

[0006]

Means for Solving the Problems In order to achieve such an object, a multilayer molded article according to the invention of claim 1 of the present invention (hereinafter referred to as "multilayer molded article of claim 1"). )
A surface layer in which the urethane resin composition is sprayed along the mold surface of the mold and molded and cured in a shape along the mold surface, and a back surface of the surface layer in which the urethane foam resin composition is sprayed on the back surface of the surface layer And a foam reinforcing layer foamed and cured along the line.

[0007] The multilayer molded article according to the second aspect of the present invention (hereinafter referred to as "multilayer molded article of the second aspect").
Has used the multilayer molded article of claim 1 for exterior parts of automobiles.

[0008] The method for producing a multilayer molded article according to the invention of claim 3 of the present invention (hereinafter referred to as "the production method of claim 3") is a method for producing a molded article having a surface shape of a molded article. A surface layer forming step of spraying the urethane resin composition on the mold surface, and a foam reinforcing layer forming step of spraying the urethane foam composition on the back side of the surface layer to form a foam reinforcing layer along the back shape of the surface layer And a configuration having:

The method for producing a multilayer molded article according to the invention described in claim 4 of the present invention (hereinafter referred to as “production method of claim 4”) is the same as the production method of claim 3, except that the urethane resin composition The urethane foam resin composition is obtained by mixing a first raw material composition containing a polyol and a second raw material composition containing an isocyanate in the middle of a flow path to be sent to a spray nozzle.

[0010] The method for producing a multilayer molded article according to the invention of claim 5 of the present invention (hereinafter referred to as "the production method of claim 5") is the method of claim 3 or claim 4, Fast-curing urethane resin compositions and foamed urethane resin compositions were used.

In the present invention, the urethane resin serving as the surface layer preferably has a flexural modulus of about 400 MPa to 500 MPa and is excellent in low-temperature flexibility. For example, Ultratan 5365 manufactured by Futura Tech Japan Co., Ltd. Can be used. On the other hand, the urethane foam resin to be the foam reinforcing layer is preferably a relatively hard one having a flexural modulus of about 150 MPa to 200 MPa. For example, Ultrafoam 5170 manufactured by Futura Tech Japan can be used. The expansion ratio of the foam reinforcing layer is not particularly limited, but is preferably about 2 to 5 times, and more preferably about 3 to 4 times.

Incidentally, a surface layer formed by using Ultratan 5365 or Ultratan 5410 manufactured by Futura Tech Japan Co., Ltd., and a foam reinforcing layer formed by using Ultraform 5170 manufactured by Futura Tech Japan Co., Ltd. The thickness of the surface layer is preferably about 0.1 to 10 mm, and the thickness of the foam reinforcing layer is preferably about 0.3 to 30 mm.

In the present invention, fast-curing means that curing is completed within 20 minutes, preferably within several minutes after spraying. Further, the urethane resin composition used for the surface layer is preferably degassed by blowing dry air, nitrogen gas, or the like into the raw material composition before spraying. That is, if air remains in the raw material composition, air bubbles may remain in the surface layer.

Further, the multilayer molded article of the present invention has a structure for preventing the foam reinforcing layer from impregnating with water on the back surface of the foam reinforcing layer.
For example, the back surface protective layer may be formed using the same urethane resin composition as the surface layer. Further, in the present invention, additives such as an inorganic filler, a colorant, and an ultraviolet absorber may be added to the urethane resin composition and the foamed urethane resin composition as necessary.

The mold used in the method for producing a multilayer molded article according to the present invention is not particularly limited, but can be obtained, for example, as follows. That is, first, a wooden mold having the same surface irregularities as the multilayer molded product to be obtained or a multilayer molded product itself to be obtained is prepared as a prototype, and a release agent is applied to the surface of the prototype. At the same time, after unneeded parts are masked with a gum tape etc., uncured resin such as the same resin composition as the urethane resin to be the surface layer is sprayed on the exposed part of the prototype, and after the resin is cured, the cured body is peeled from the prototype Can be obtained. Further, a foamed resin layer for reinforcement may be provided on the back side of the cured body. The material of the mold is
Although not particularly limited, those made of the above-mentioned resin are preferable, and are excellent in manufacturing cost and handleability, and the resin is preferably a urethane resin-based resin.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below.
This will be described in detail with reference to the drawings. 1 and 2 show one embodiment of a multilayer molded product according to the present invention.

As shown in FIGS. 1 and 2, the multilayer molded article 1 is an aero part as an exterior member attached below a bumper of an automobile. As shown in FIG. It has a reinforcing layer 3 and a back surface protective layer 4. The surface layer 2 has a flexural modulus of 400 MPa to 500 M.
It is formed of a urethane resin having excellent low-temperature flexibility of about Pa.

The foam reinforcing layer 3 has a flexural modulus of 150 MPa.
It is formed of a urethane foam resin having a foaming magnification of 3 times at about a to 200 MPa. The back surface protective layer 4 is formed of the same urethane resin as the surface layer 2 so as to conceal the irregularities on the back side of the foam reinforcing layer 3 and to prevent impregnation of water into the foam reinforcing layer 3. ing.

The multilayer molded article 1 can be manufactured as follows. First, as shown in FIG. 3, a mold 5 having a shape conforming to the surface shape of the aero part to be obtained was prepared, and a release agent such as wax was applied along the mold surface 51 of the mold 5. Later, FIGS. 4 and 5
As shown in the figure, a first raw material composition (having a polyol as a main component) 71 and a second raw material composition (having a isocyanate as a main component) 72 contained in a container 7 such as a drum can.
Are respectively sent to the spray spray 8, and the fast-curable urethane resin composition 81 obtained by mixing the first raw material composition 71 and the second raw material composition 72 from the spray 8 is sprayed onto the mold surface 51. The above is cured to form the surface layer 2.

Next, although not shown, the rapidly curable urethane resin composition is sprayed in the same manner from another spray spray 8 on the back side of the surface layer 2 and foamed and hardened on the back side of the surface layer 2. Thus, the foam reinforcing layer 3 is formed. Then, the same quick-curing urethane resin composition as the surface layer 2 is sprayed on the back side of the foam reinforcing layer 3 and cured on the back side of the foam reinforcing layer 3 to form the back surface protective layer 4.

Next, the edge is cut using a cutter knife or scissors or the like so that the mold can be easily removed, and cooled with air or the like as necessary (because the resin spraying temperature is about 65 ° C.). And as shown in FIG.
The obtained cured product 10 is removed from the mold 5. Then, unnecessary portions 1 such as burrs on the peripheral edge of the obtained molded cured product 10
1 is cut out with a cutter knife, scissors, or the like, and finishing is performed, whereby the multilayer molded article 1 can be obtained. Also,
After the surface layer 2 is roughened with sandpaper or the like, if necessary, the obtained multilayer molded article 1 can be applied with a cosmetic paint or the like to apply makeup.

According to the method for producing the multilayer molded article 1, as described above, the surface layer 2, the foam reinforcing layer 3 and the back surface protective layer 4 can be molded only by spraying the urethane resin composition or the urethane foam resin composition. Therefore, the molding time is shorter than that of a conventional fiber-reinforced plastic molded product, and the productivity is improved. In particular, productivity is improved because a fast-curing resin composition is used. That is, one multilayer molded article 1
It takes only about 20 to 30 minutes to produce the product. Further, since it is not necessary to use an expensive mold such as press molding or injection molding, and the molding die can be produced simply and inexpensively, the production cost can be reduced.

On the other hand, the obtained multilayer molded article 1 is formed of urethane resin and does not contain reinforcing fibers such as glass fibers, so that it has high recyclability and is reinforced by the foam reinforcing layer 3. Therefore, even if it is lightweight, easy to handle, and thin, there is little bending and the like, and it is excellent in strength.

The present invention is not limited to the above embodiment. For example, in the above embodiment, the back surface protection layer is provided on the back surface side of the foam reinforcing layer, but may be omitted. Also, the same urethane resin composition as that of the surface layer is sprayed onto the joint portion while urging the two multilayer molded articles with the foam reinforcing layer side facing each other and the edges thereof are temporarily bonded with an adhesive or the like. When the resin is cured, a hollow multilayer molded article can be obtained.

[0025]

As described above, the multilayer molded article and the method for producing the same according to the present invention can provide a multilayer molded article which is low in cost and highly recyclable. In.

In particular, according to the manufacturing method of the fourth and fifth aspects, it is possible to obtain a multi-layer molded product with higher productivity and better quality.

[Brief description of the drawings]

FIG. 1 is a perspective view showing one embodiment of a multilayer molded product according to the present invention.

FIG. 2 is a sectional view taken along line XX of FIG.

FIG. 3 is a perspective view showing one embodiment of a method for producing a multilayer molded article according to the present invention, and showing a molding die used in the method.

FIG. 4 is a schematic diagram schematically showing an example of a urethane resin coating device used in this method.

FIG. 5 is a perspective view showing a state in which a surface layer is formed on the mold of FIG. 3;

FIG. 6 is a perspective view showing a state in which a cured product is removed from the mold of FIG. 3;

FIG. 7 is a perspective view of a shaped and cured product obtained by using the mold of FIG. 3;

FIG. 8 is a perspective view of an automobile equipped with aero parts.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Multilayer molded article 2 Surface layer 3 Foam reinforcement layer 4 Backside protective layer 5 Mold 51 Mold surface 8 Spray nozzle 81 Urethane resin composition 71 First raw material composition 72 Second raw material composition

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (Reference) B60R 13/04 B60R 13/04 // B29K 75:00 B29K 75:00 B29L 9:00 B29L 9:00 31:30 31 : 30

Claims (5)

[Claims] An urethane resin composition is sprayed along a mold surface of a molding die, and the surface layer is molded and cured into a shape along the mold surface. A foamed urethane resin composition is sprayed on the back surface of the surface layer. A multilayer molded article comprising a foam reinforcing layer foam-cured so as to conform to the back surface shape of the surface layer. 2. The multilayer molded article according to claim 1, which is an exterior part of an automobile. 3. A surface layer forming step of spraying a urethane resin composition onto a mold surface of a molding die formed into a surface shape of a molded article;
A method of forming a foamed reinforcing layer, which comprises spraying a urethane foam resin composition on the back side of the surface layer to form a foamed reinforcing layer along the back surface shape of the surface layer. 4. A urethane resin composition and a foamed urethane resin composition are mixed in the middle of a flow path for feeding a first raw material composition containing a polyol and a second raw material composition containing an isocyanate to a spray nozzle. The method for producing a multilayer molded article according to claim 3, which is obtained. 5. The method for producing a multilayer molded product according to claim 3, wherein the urethane resin composition and the urethane foam resin composition are quick-curing.