JPS58163633A - Monolithical molding method for fine cell structural body having different physical properties part - Google Patents

Abstract

PURPOSE:To prevent the production of a pin hole at a joint part, by a method wherein a boundary base material made of a gas permeable material is located at a boundary position partitioning a mold into a given parts, and foaming resin materials, which are compounded so that they are different in physical properties from each other, are respectively injected through different injection ports. CONSTITUTION:A boundary base material 50, made of a gas permeable material, such as non-rigid polyurethane foam, felt, having a communicating breathing structure, is situated at a boundary position which partitions a cavity in a mold 60 into given parts. A given quantity each of foaming material resins 20a and 30a, which are compounded so that they are different in physical properties from each other, is injected through their respective different injection ports 63 and 64, and is impregnated into the boundary base material 50 for joining. The produced gas and air in the mold are guided to the outside through the boundary base material 50.

Description

DETAILED DESCRIPTION OF THE INVENTION This invention provides a fine cell structure having different physical properties,
% relates to the method of integrally molding the plate-shaped body.

For side parts, such as automobile body panels or construction panels, polyurethane resin raw materials are injected into blow-molded lids using the so-called high-pressure reaction injection molding method.
On the surface, a molded product with a fine cell structure is used, which is not foamed at all and the volume of bubbles gradually increases toward the inside (core). The molded product has many advantages, such as being lightweight, easily obtaining various physical properties, and having excellent appearance including finishing processes such as painting4.

On the other hand, there are cases in which the physical properties, such as flexural modulus or specific gravity, of one part and another part of these single continuous molded bodies are changed. Alternatively, there are cases where it is desired to form a plurality of plates having different physical properties into a single continuous plate.

However, simultaneous molding or simultaneous molding, in which a part of the molded body is made of a different resin raw material than other parts, is technically complicated and complicated. There are difficult problems. The main problems are firstly the definition of the boundary position and secondly the bonding strength at the boundary. In particular, in the case of the above-mentioned plate-shaped molded product, unlike other molded products of a certain shape, the ratio of thickness to area is extremely small, and this problem becomes a serious problem. Furthermore, as an important issue in simultaneous molding,
There remains the problem of dealing with bubble unevenness, pinholes, etc. that occur near the joints, ie, boundaries, of foamed resin raw materials.

This invention therefore solves these problems, namely (1) definition of the boundary position, (2) bonding strength at the boundary, and (3)
It was proposed primarily to deal with the occurrence of bottle holes. Examples will be specifically described below.

FIG. 1 of the accompanying drawings is a perspective view showing a round plate-shaped molded body 10 obtained by the method of the present invention together with its cross section,
This molded body 10 has a fine cell structure, such as a polyurethane resin, which is composed of a dense, almost non-foamed skin portion on the outer surface 11, and in which the cell volume gradually increases toward the inside 12. 9. The molded body 1o is composed of portions 2o and 3o having different physical properties, here different flexural moduli. The boundary portion 4o between the flesh portions 2o and 30 is formed as a portion impregnated with the resin raw material constituting the portions go> and 3o in the boundary base material 60 which is covered with an air-permeable material.

FIG. 3 is a perspective view of a molded body 10m showing another embodiment, in which portions 31 and 12 having round physical properties different from those of the armpit portion 21 are formed on the left and right sides of the portion 21. The boundaries of each portion are formed in predetermined straight or curved shapes as indicated by reference numerals 41 and 42.

Next, the method of the present invention will be explained using the molded body 1O shown in FIG. 1 as an example. Figure S shows the upper mold 61 and the lower mold 6.
2-like molding! 16o and two injection ports 6 on the left and right.
3.64.

First, a boundary base material 50 made of a breathable material is placed at a boundary position that divides the hollow portion of the mold 60 into predetermined portions. The air-permeable boundary base material 50 is, for example, a flexible polyurethane foam with a delayed cell structure or a plastic 7 such as polyethylene, polypropylene, or vinyl chloride.
Ohm, the front is felt, non-woven fabric, glass fiber mat,
A fibrous material such as a string is exemplified. The above boundary base material 5o is held and disposed on the upper surface 1161W of the molded mao 611LK, for example, by an adhesive 65, as shown in FIG.

It goes without saying that the boundary base material 5o is arranged in a desired shape such as a curved bell shape according to the shape of the boundary line as shown in the nine examples shown in FIG. After 9 minutes, the lid is tightened and the foamed resin raw material is injected.

Nine foaming raw material resins B are blended so that their physical properties are different from each other.
oa and Boa are each different benign 1: I63, 64) formed by the boundary base material 5011C and 9 molding 11
These resin raw materials 1! are injected in a predetermined amount into 60 predetermined compartments (1g5 figure (&))'. Oa, 510a foams and fills a predetermined section in the lid, and also invades and joins the boundary base material 6o existing at the boundary. On the other hand, since the boundary base material 5o is made of an air-permeable material as shown in the circle above, each resin raw material 110a, 3C1a penetrates into this and forms an immersion hardened part at the boundary (see Figure 1). To))
At the same time, since it is a gaseous substance, the air in the molding layer in the generated gas that may remain during the bonding of both foamed resin raw materials is led to the outside through the boundary base material 6°.
This prevents pinholes from forming at the joint.

Figure 6 is for comparison with the method of this invention.

It is a cross-sectional view when the same raw materials 20*, 30a and the same molding 1160 as in the above embodiment are used to integrally mold without disposing a boundary base material. In this case, if the shape is simple, defining the boundary position is complicated, as it requires accurate weighing of the wood #I raw material, control of foaming time, timing of injection, etc. 1I
It is possible. Of course, it is almost impossible to define a diagonal or curved boundary as shown in FIG. However, judging from the appearance of the molded product, as shown in FIG. 6(b), it is inevitable that a pinhole H will be formed near the upper 116111 plane of the joint J of the resin raw materials 20a and 30a. Furthermore, as will be understood from the following experimental examples, the tensile strength of the boundary portion obtained by the present invention is significantly inferior to that of the round product.

(Table 1) As mentioned above, according to the method of the present invention, the boundary position of the portions having different first K physical properties can be easily and arbitrarily defined. Secondly, since the metal contact position of the base part, that is, the impregnation where the foamed resin raw material penetrates into the boundary base material made of a breathable material is formed at the boundary part, the bond between the two parts is sure and strong. I can do it. Thirdly, it has become possible to completely avoid the occurrence of pinholes, etc. at the joints, which cannot be avoided when a plurality of foamed resin raw materials are simultaneously molded in a mold. As described above, the present invention is extremely advantageous and effective in obtaining a single continuous molded body having a fine cell structure having different physical properties, particularly a plate-shaped molded body. Finally, as an example of different physical properties of each part in the example, examples of blending of polyurethane resin raw materials in nine parts with different flexural modulus will be described.

[Formulation example]

・Polyurethane resin raw material ZOa (flexural elasticity wheel small) polyether polyol 50 parts by weight (2-functional 1-flat H 6.ooo) Vinyl polymer copolymer polyol 40 (Mitsui Nisso POP31-as) Propylene glycol 23 MDI prepolymer 110 (?r@e 1100%e
251G) Trichlorou fluoromethane
3.0 triethylenediamine 0
．． 4 Djibouti A bite 1 Kutsuurate
o, ooaOthers (pigments, etc.)
Required amount Polyurethane resin raw material 30 parts (high flexural modulus) Polyether polyol 90 parts by weight (
xWh H amount a, ooo) Propylene glycol 2! sMDI prepolymer 170 (Fr... Violet cod
, gsl) ) 90 Rofluoromethane 3.0
Triethylenediamine 0.3 Dibutyltin dilau V-) 0. oxg Glycerin 6.0 Function (Ij material, etc.) Required amount

[Brief explanation of drawings]

Fig. 1g is a perspective view showing a nine molded product obtained by the method of the present invention together with its cross section, Fig. 2 is a perspective view showing another embodiment, Fig. 3 is a perspective view of the molded IIO, and Fig. 4 is its outline. FIG. 5 is a cross-sectional view of a mold showing the molding method of the present invention, and No. 6 Igl is an enlarged sectional view of a molded product formed without using a boundary member. 10. 10mm... Molded body with IIJI cell structure, 20.
21, 30, 31.32... part of molded body, 20a,
30a... Foamed resin raw material, 40.41.42...
Boundary part, 50... Boundary member, 60... Molding mold,
61...upper type, 62...lower type, 63.64
...Injection port, J...Joint part, ■...Pinhole. Patent applicant Inoue MBC Co., Ltd. Figure 3 Figure 4 Figure 5 Figure 6-1?

Claims (1)

[Claims] 1. Obtaining a molded product with a fine cell structure in which a single continuous surface has portions having different physical properties, and the cell volume gradually increases as it progresses inside; Molding (Place a breathable material at the boundary position that divides the mold into predetermined parts)
After arranging a boundary base material, a mold clamping bale, nine foamed resin raw materials mixed with different physical properties are injected into a predetermined section of the mold (each having a different benign inlet), and integrally foam-molded. By this, each of the foamed resins is integrally joined to the boundary base material while forming an O-impregnated part at the joint part. Molding method. λ breathable substance] is made of a plastic foam having an open cell structure or a fibrous material such as felt or glass fiber mat or non-woven fabric or twine cape. Fine cells with. Method of integrally molding the structure. (5) A method for integrally molding a fine cell structure having portions with different physical properties as set forth in claim 1, wherein the boundary base material is temporarily fixed to the upper die surface of the molded IIO by an adhesive force.