JPH04279308A - Blow molding filled with foam body - Google Patents

Abstract

PURPOSE:To improve the tone feelings of a blow molding. CONSTITUTION:Into time blow molding hollow part composed of using ABS resin, a foam body is filled. As the foam body, it is preferable to employ urethane foam, an ABS resin foam body, and an AS resin foam body that each has excellent adhesiveness with ABS resin.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a blow-molded product that has excellent sound quality, specifically, the impact noise generated when struck is small and reverberation noise is less likely to occur, and the appearance quality is excellent.

0002

[Prior art] Blow molding is mainly used as a technique for molding hollow containers from polyolefin resins and polyester resins, but it is also used for molding large parts because large molded products can be obtained using relatively simple equipment. It is also attracting attention as a technology, and the resin materials that can be molded are expanding to include polyphenylene oxide resins, ABS resins, etc.

Products obtained by blow molding have a hollow interior, so they have the advantage of being lighter than products obtained by, for example, sheet molding or compression molding, but on the other hand they have inferior sound quality. In other words, it has the drawbacks of producing a loud impact sound when struck and easily causing reverberation, which limits its use in fields that place emphasis on the sound quality when struck, such as high-end office furniture and automobile air spoilers. I didn't get it.

On the other hand, the technique of filling cavities with foam is known for the purpose of improving the rigidity of molded products, and is used in sports equipment made of polyolefin resins, such as surfboards. However, since the application of the invention requires excellent sound quality as well as product appearance quality, it is problematic to use polyolefin resin, which has poor external appearance of molded products and poor secondary processability such as painting and printing. was there.

[0005]

[Problems to be Solved by the Invention] In view of the current situation, it is an object of the present invention to provide a product with excellent sound quality and appearance quality without sacrificing the lightness of the product, which is an advantage of blow molded products. It is something to do.

[0006]

[Means for Solving the Problems] That is, the present invention is a blow molded product made of ABS resin whose cavity is filled with a foam. In particular, the foam is urethane foam, A
The molded product made of BS resin foam or AS resin foam has good affinity between the foam and ABS resin, and can achieve a significant improvement in sound quality. The present invention will be explained in more detail below.

[0007] The resin material used in the present invention is ABS resin. Polyolefin resins have problems such as poor appearance and poor secondary processability, and because the resin itself has low rigidity, molded products are easily deformed when fillers are injected and foamed. Advantages of the blow molding method include the need to increase the thickness of the molded product or use a jig to prevent deformation during foaming in order to manufacture parts with high precision that are assembled with other parts, such as spoilers. This may impair the lightness and ease of molding of the product. ABS resin also has the advantage of having higher strength at the pinch-off area than polyolefin resins.

Although it is possible to fill the cavity of a blow-molded product made of polyphenylene oxide resin with foam, the resin has poor chemical resistance, so it is difficult to use foaming agents such as chlorofluorocarbon gas, low-boiling organic solvents, etc. Cracks may occur in molded products due to contact with. In addition, since the resin has poor thermal stability, the residue in the molding machine generates a thermally crosslinked body (gel), which adheres to the molding machine die and causes a severe die line, or the gel itself gets mixed into the product, deteriorating the appearance. There are problems such as.

[0009] The ABS resin used in the present invention may be of a type designed for ordinary injection molding, but it is preferable to use a type designed for blow molding for molding large parts. In other words, in order to form a large parison without drawdown, the melt viscosity must be high in the low strain rate region at the blow molding temperature, specifically, the strain rate measured at the Vicat softening temperature plus 100°C. Extensional viscosity at 1.0 sec -1 is 1.6 x 105
It is an ABS type that is better than Poise. Such ABS products are manufactured by adjusting the molecular weight and molecular weight distribution of ABS products (patent application No. 2003).
37275), or by slight crosslinking of the AS (acrylonitrile-styrene copolymer) component constituting the ABS resin (Japanese Patent Application No. 2-59850).

In addition to acrylonitrile, butadiene, and styrene, ABS resins include rubber polymers such as styrene-butadiene copolymer, acrylonitrile-butadiene copolymer, acrylic ester rubber polymer, and ethylene-propylene copolymer. Rubber, etc. may contain copolymers such as methacrylonitrile, α-methylstyrene, (meth)acrylic acid ester, and maleimide derivatives as matrix components, and the ratio of these components is determined depending on the strength, heat resistance, etc. required for the product. It can be set as desired. There are no restrictions on the blow molding method, and a molded article in the desired shape may be obtained using an ordinary blow molding machine.

[0011] The filling of the foam into the cavity can be carried out by a conventional urethane foaming method, a foaming method using resin beads pre-impregnated with a foaming agent, or the like. During the foaming operation, the foaming temperature must be selected appropriately so that the molded product does not undergo thermal deformation, and the filler inlet and air vent holes must be arranged so that the molded product cavity is evenly filled with the foam. There is a need.

Foams include urethane and resin beads such as polystyrene, modified polyphenylene oxide,
Any material that can be made into a foam, such as polyvinylidene chloride, AS resin, ABS resin, or polyethylene, is fine, but in order to improve the sound quality, it is more preferable that the interface between the ABS resin and the filler is sufficiently bonded. affinity with resin,
It is preferable to use urethane foaming, which has excellent adhesive properties, or a bead foaming method using ABS resin or AS resin.

[0013] Blow-molded products filled with foam that has excellent adhesion to ABS resin improve the sound quality and at the same time improve the product's rigidity and impact resistance, making it an extremely excellent product in practical use. . Note that it is optional to perform secondary processing such as painting, plating, printing, etc. on the blow-molded product filled with the foam of the present invention.

[0014]

[Examples] The present invention will be explained below based on Examples. Example 1 STYLAC (registered trademark) ABS BL-15 (ABS resin for blow molding, manufactured by Asahi Kasei Corporation, heating deformation temperature 96°C
Type) is used, and the air spoiler for automobiles (total length 1300 mm) is used.
mm, weight 1.3 kg). An injection port was made at a position 100 mm from the end of the molded product, and air vents were made at both ends, and after preheating to 40° C., 135 g of a polyurethane foam stock solution having the following composition was injected, foamed, and cured.

Stock solution composition 1 Isocyanate HYCEL 131P
100 copies 2 premix
HYCEL MR-245C 90 copies
(Note: Both are manufactured by Toho Chemical Co., Ltd.) The premix contains 22% of the blowing agent Freon 11. Air spoilers filled with urethane foam did not produce the sound quality of unfilled products, that is, no airborne sound or reverberation when struck, and an improvement in sound quality was observed. When the same product was painted (two-component urethane), a product with excellent paint film clarity and film adhesion strength was obtained.

[0016]

[Effects of the Invention] The present invention improves the aerobic sound and reverberation when struck without sacrificing the lightweight advantage of blow-molded products, and at the same time provides the excellent appearance and secondary processability of ABS resin. A blow molded product can be obtained that has both the following properties.

Claims (2)

[Claims] 1. A blow-molded product made of ABS resin, characterized in that a cavity is filled with a foam. [Claim 2] The foam is urethane foam or ABS
The blow molded article according to claim 1, which is a resin foam or an AS resin foam.