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Injection foam molding method and apparatus therefor

A technology of injection foaming and injection molding, applied in the direction of coating, etc., can solve the problems of insufficient exhaust gas, poor appearance of injection foamed moldings, etc., and achieve the effect of preventing vortex marks

Active Publication Date: 2012-01-18
PRIME POLYMER CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0008] However, as described in this patent document 3, in order to form uniform independent cell cells, the cavity is depressurized before the core retraction step, the gas located at a position away from the exhaust position is pushed in by the resin pressure. , so the air cannot be fully exhausted, and the appearance of the injection foamed molded product may be poor.

Method used

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  • Injection foam molding method and apparatus therefor
  • Injection foam molding method and apparatus therefor
  • Injection foam molding method and apparatus therefor

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0137] (1) Manufacturing device

[0138] Use a mold with a cavity size of 850×450mm for obtaining figure 1 A mold for an injection foam molded product in the shape of a door trim as shown. The metal mold was adjusted so that the thickness dimension of the cavity in the state where the metal mold was completely closed was 1.6 mm.

[0139] A shared edge structure is formed around the cavity in the metal mold. Furthermore, a circumferential gas flow path with a width of 5 mm and a height of 15 mm was provided on the outer periphery of the base end side of the convex portion of the fixed-side mold. In addition, the gas flow path communicates with the mold cavity through the gap between the shared sides. Furthermore, a rubber sealing member (O-ring) is provided on the outer periphery of the gas flow path. Contact with sealing parts to ensure the airtightness of cavity and gas flow path.

[0140] In addition, connected to the gas flow line figure 1 and figure 2 The boosting d...

Embodiment 2～5

[0149] [Examples 2-5, Comparative Examples 1-6]

[0150] In addition to the CO 2 Addition amount, cavity internal pressure, exhaust timing (time from the end of injection to vacuuming), vacuuming implementation status, and vacuum degree were changed as shown in Table 1 and Table 2, and obtained in the same manner as in Example 1. Injection foam molding.

[0151] It should be noted that the saturated solution pressure in Examples 2,3 and Comparative Examples 1~4 is the same as that of Example 1, and the saturated solution pressure of Example 4 and Comparative Example 5 is 0.42MPa, and the saturated solution pressure of Example 5 and Comparative Example 6 is 0.42MPa. The dissolution pressure is 0.31MPa.

[0152] (4) Evaluation

[0153] The surface of the obtained injection foamed molded product was visually observed for occurrence of swirl marks, corrugated or indeterminate depressions, and evaluated on the following three scales. The results are shown in Tables 1 and 2 belo...

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Abstract

After gas is introduced into a cavity (113) formed by mold clamping, and a pressure thereof is raised, a resin material (X) of a thermoplastic resin containing a foaming agent is injected. After a skin layer is formed, and at the same time as or after a core-back operation for foaming the resin material (X) is performed, the gas in the cavity (113) is vacuum suctioned to make the inside of the cavity (113) lower than the atmospheric pressure. The resin is cooled and solidified to obtain an injection foam molded body. Before the completion of solidification, the gas between the resin material (X) and an inner surface of the die (110) is reliably discharged to the outside of the cavity (113) to prevent the recess on the surface caused by accumulated gas and the generation of a swirl mark.

Description

technical field [0001] The present invention relates to an injection foam molding method and an apparatus thereof for obtaining an injection foam molded article by injection molding a thermoplastic resin containing a foaming agent. Background technique [0002] Currently, for example, injection foam moldings are used in door moldings of automobiles, and various methods are known as injection foam molding methods for obtaining such injection foam moldings (for example, refer to Patent Documents 1 to 3). . [0003] Patent Document 1 describes that when filling molten resin into a cavity pressurized with pressurized gas, the unfilled portion in the cavity is released or evacuated to instantaneously decompress and fill the molten resin with ease. easy. [0004] However, in the method of discharging the pressurized gas in the state of leaving the unfilled part described in Patent Document 1, so-called swirl marks (swirl mark) may be generated in the part corresponding to the un...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B29C45/00B29C45/26B29C45/56B29C45/70B29C45/77B29K105/04
CPCB29C44/586
Inventor 小原智之
Owner PRIME POLYMER CO LTD