JP2906566B2 - Multilayer resin container laminated structure - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a laminated structure of a multilayer resin container that can easily confirm the presence or absence of an outer adhesive layer and an inner adhesive layer even after lamination.

(Prior Art) As a multilayer resin container, for example, there is a resin gasoline tank of an automobile, and the wall of this gasoline tank has an outermost layer 1, an outer adhesive layer 2, an intermediate layer 3, as shown in FIG. The inner adhesive layer 4 and the innermost layer 5 are laminated in this order, the outermost layer 1 and the innermost layer 5 are made of high-density polyethylene layers of the same material to maintain strength, and the intermediate layer 3 is made of nylon to prevent gasoline from permeating. A three-layer, five-layer laminate structure in which the outer adhesive layer 2 and the inner adhesive layer 4 are maleic anhydride-modified polyethylene layers of the same material to bond the high-density polyethylene layer and the nylon layer together. have.

As shown in FIG. 8, a high density polyethylene, a maleic anhydride-modified polyethylene with a second screw 7 and a nylon with a third screw 8 are placed in a head 9 of a molding machine as shown in FIG. After being fed, where the layers are stacked, they are extruded from the lower end of the head 9 as a parison 10 and the parison is blow molded in a mold to form the wall of the gasoline tank.

Note that fine powder of carbon black is added to the high-density polyethylene layers of the outermost layer 1 and the innermost layer 5 in order to improve weather resistance.

(Problems to be Solved by the Invention) By the way, in such a three-type five-layer resin gasoline tank, if the adhesive layers 2 and 4 are partially interrupted, the nylon intermediate layer 3 and the high-density polyethylene Exfoliation between the outer layer 1 and the innermost layer 5 causes a drop in impact performance and leakage of gasoline, so the presence or absence of the adhesive layers 2 and 4 is extremely important.

However, in the conventional laminated structure described above,
Since the adhesive layers 2 and 4 are covered by the head 9 during molding and are not particularly colored, they are hidden by the carbon black added to the outermost layer 1 after molding, so that the presence or absence of the adhesive layers 2 and 4 can be grasped. Therefore, there is a problem that it is difficult to obtain a highly reliable resin gasoline tank.

The present invention provides a laminated structure that advantageously solves the above problem.

(Means for Solving the Problems) The laminated structure of the multilayer resin container of the present invention is formed by laminating an outermost layer, an outer adhesive layer, an intermediate layer, an inner adhesive layer, and an innermost layer in this order. The outer adhesive layer and the inner adhesive layer are of the same kind of material, and the outer adhesive layer and the inner adhesive layer are of the same kind of material.They are made of three and five layers, and the outermost layer is made substantially transparent. In this case, the inner adhesive layer is densified by adding a fine powder of metal or oxide thereto.

(Operation) In such a laminated structure, after molding, the outermost layer becomes substantially transparent and the outer adhesive layer is colored, so that the presence or absence of the outer adhesive layer can be easily visually checked from outside the outermost layer. In addition, since the inner adhesive layer is densified by fine powder of metal or oxide and easily generates an ultrasonic echo, the presence or absence of the inner adhesive layer can be easily determined by an ultrasonic flaw detector.

Therefore, according to the laminated structure of the present invention, the presence or absence of the outer adhesive layer and the inner adhesive layer can be easily and reliably grasped, and a highly reliable resin container can be easily manufactured.

Embodiment An embodiment of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a cross-sectional view showing an embodiment in which the laminated structure of the multilayer resin container of the present invention is applied to a wall of a resin gasoline tank. The wall here has an outermost layer 11 having a thickness of about 3 mm. An outer adhesive layer 12 having a thickness of about 100 μm, an intermediate layer 13 having a thickness of about 100 μm, and an inner adhesive layer 14 having a thickness of about 100 μm.
And the innermost layer 15 having a thickness of about 3 mm is laminated in this order.The outermost layer 11 and the innermost layer 15 are made of high-density polyethylene layers of the same material to maintain strength, and the intermediate layer 13 prevents gasoline permeation. The outer adhesive layer 12 and the inner adhesive layer 14 were maleic anhydride-modified polyethylene layers of the same material as each other in order to adhere the high-density polyethylene layer and the nylon layer.
It has a three-layer five-layer structure.

Thus, here, the carbon black conventionally added is removed from the high-density polyethylene layers of the outermost layer 11 and the innermost layer 15, and an ultraviolet absorber is added only to the outermost layer 11 instead.

Examples of the ultraviolet absorber include benzophenone, salsylate, cyanoacrylate, benzoate,
Benzotriazole-based or the like can be used. In this example, 0.1% by weight of benzotriazole-based Tinuvin 900, manufactured by Ciba-Geigy, is used.

The outermost layer 11 is made translucent by the addition of the ultraviolet absorber.

The outer adhesive layer 12 is colored red by adding 5% of a master batch LM4076 Red (trade name of Toyo Ink Co., Ltd.) as a pigment, so that the outer adhesive layer 12 itself can be easily seen visually. ing.

Further, to the inner adhesive layer 14, 3% by weight of SP Ace SP7100DRY of Kawasaki Techno Research Co., Ltd., which is a stainless flake, is added as a metal fine powder in this embodiment.

By adding the metal fine powder, the inner adhesive layer 14 becomes the innermost layer 15.
The inner adhesive layer 14 is more likely to generate ultrasonic echoes.

In the laminated structure, the resin as a raw material of each layer is supplied into the same head as shown in FIG. 8 by five screws of the molding machine, and after each layer is stacked there, as a parison from the lower end of the head. The parison is extruded and blow molded in a mold to form the wall of the gasoline tank.

In such a laminated structure, since the outermost layer 11 is substantially transparent and the outer adhesive layer 12 is colored red, the outer appearance of the parison or the gasoline tank blow-molded from the parison is used. By visual inspection, the presence or absence of the outer adhesive layer 12 can be easily grasped from outside the outermost layer 11.

Also, since the inner adhesive layer 14 is densified by metal fine powder and it is easy to generate an ultrasonic echo, if the parison or a gasoline tank blow-molded from the parison is inspected with an ultrasonic flaw detector, Fig. 2 (a)
As shown in FIG. 3B, the presence or absence of the inner adhesive layer 14 can be easily grasped as compared with the conventional laminated structure shown in FIG.

Therefore, according to the laminated structure of this embodiment, the outer adhesive layer 12
In addition, the presence or absence of the inner adhesive layer 14 can be easily and reliably grasped, and a highly reliable resin gasoline tank can be easily manufactured.

FIG. 3 shows the results of testing the degree of ultrasonic echo discrimination and the adhesive strength by changing the amount of stainless flake added to the inner adhesive layer 14 in the above-mentioned laminated structure. As described above, if the addition amount of the metal fine powder is too small, the ultrasonic echo disappears, and if the addition amount is too large, the adhesive strength decreases. The optimum amount of addition when using the above stainless flakes was 0.5% by weight to 20% by weight.

FIG. 4 is a sectional view showing another embodiment of the present invention. In the laminated structure of this embodiment, instead of the red pigment-modified modified polyethylene outer adhesive layer 12 in the previous embodiment, Toyo Ink Co., Ltd. The modified polyethylene outer adhesive layer 16 which is colored blue by adding the trade name Masterbatch LM7084 Blue is provided, so that the outer adhesive layer 16 itself can be easily visually observed.

In place of the modified polyethylene inner adhesive layer 14 containing metal fine powder in the previous embodiment, zinc oxide whiskers of Matsushita Electric Industrial Co., Ltd., which are isotropic whiskers of zinc oxide as shown in FIG. A modified polyethylene inner adhesive layer 17 to which is added is provided, whereby the inner adhesive layer 17 is densified more than the innermost layer 15, and
Since the inner adhesive layer 17 easily generates ultrasonic echoes, the zinc oxide whisker has a large acoustic impedance. Therefore, in this embodiment, the addition amount is 1% by weight.

With the laminated structure of this embodiment, the same operation and effect as those of the previous embodiment can be obtained.

FIG. 6 shows the results of testing the degree of ultrasonic echo discrimination and the adhesive strength by changing the amount of zinc oxide whiskers added to the inner adhesive layer 17 in the above-mentioned laminated structure. As described above, the optimum amount of zinc oxide whiskers was 0.5% to 20% by weight.

As described above, the present invention has been described based on the illustrated examples. However, the present invention is not limited to the above-described examples. For example, the pigment to be added to the outer adhesive layer has a good dispersibility in the material resin of the adhesive layer. Any color or material other than the above examples may be used.

Also, fine powders of metal or oxide to be added to the inner adhesive layer may be other than the above examples as long as the dispersibility of the adhesive layer in the material resin is good and the density of the adhesive layer can be sufficiently higher than that of the innermost layer. It may be something.

The present invention can be applied to resin containers other than the resin gasoline tank.

(Effects of the Invention) Thus, according to the laminated structure of the present invention, the presence or absence of the outer adhesive layer and the inner adhesive layer can be easily and reliably grasped.
A highly reliable resin container can be easily manufactured.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment in which a laminated structure of a multilayer resin container of the present invention is applied to a wall portion of a resin gasoline tank. FIGS. 2 (a) and 2 (b) show a conventional laminated structure and the above-described embodiment. FIG. 3 is a characteristic diagram showing the state of generation of ultrasonic echoes of the laminated structure of the example, and FIG. 3 is a graph showing the degree of ultrasonic echo discrimination and adhesion by changing the amount of stainless flake added to the inner adhesive layer in the laminated structure of the above embodiment. FIG. 4 is a sectional view showing another embodiment in which the laminated structure of the multilayer resin container of the present invention is applied to a wall of a resin gasoline tank, and FIG. FIG. 6 is an enlarged view showing the appearance of a zinc oxide whisker used in the embodiment of FIG. 6. FIG. 6 is a diagram showing the degree of ultrasonic echo discrimination by changing the amount of zinc oxide whisker added to the inner adhesive layer in the laminated structure of the above other embodiment. And adhesive strength 7 is a cross-sectional view showing a laminated structure of a conventional resin gasoline tank wall, and FIG. 8 is a screw and a head of a molding machine for producing the above-mentioned conventional laminated structure. Is a front view showing only a right half section in cross section. 11: Outermost layer of translucent high-density polyethylene containing ultraviolet absorber 12 ... Outer adhesive layer of modified polyethylene containing red pigment 13 ... Nylon intermediate layer 14 ... Inner adhesive layer of modified polyethylene containing fine metal powder 15 ... Innermost layer of high-density polyethylene 16 ... Blue pigment Modified polyethylene inner adhesive layer containing oxide fine powder 17 ... Modified polyethylene inner adhesive layer containing oxide fine powder

Claims (3)

(57) [Claims] An outermost layer (11), an outer adhesive layer (12, 16), an intermediate layer (13), an inner adhesive layer (14, 17) and an innermost layer (15).
Wherein the outermost layer and the innermost layer are made of the same material, and the outer adhesive layer and the inner adhesive layer are made of the same material. Making the outer adhesive layer colored by adding a pigment thereto, and densifying the inner adhesive layer by adding a metal or oxide fine powder thereto. Characterized by the laminated structure of the multilayer resin container. 2. The method according to claim 1, wherein the inner adhesive layer is formed as fine metal powder.
The multilayer structure of a multilayer resin container according to claim 1, wherein 0.5 wt% to 20 wt% of stainless flake is added. 3. The laminated structure for a multilayer resin container according to claim 1, wherein 0.1 to 30% by weight of zinc oxide whiskers are added as fine powder of oxide to said inner adhesive layer.