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1. WO1996002379 - METHOD FOR THE NON-RESIN FLUID-ASSISTED INJECTION MOLDING OF A RESIN

Publication Number WO/1996/002379
Publication Date 01.02.1996
International Application No. PCT/JP1994/001457
International Filing Date 02.09.1994
Chapter 2 Demand Filed 18.09.1995
IPC
B29C 45/17 2006.01
BPERFORMING OPERATIONS; TRANSPORTING
29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
CSHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
45Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor
17Component parts, details or accessories; Auxiliary operations
CPC
B29C 2045/1707
BPERFORMING OPERATIONS; TRANSPORTING
29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
CSHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
45Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor
17Component parts, details or accessories; Auxiliary operations
1703Introducing an auxiliary fluid into the mould
1704the fluid being introduced into the interior of the injected material which is still in a molten state, e.g. for producing hollow articles
1706using particular fluids or fluid generating substances
1707using a liquid, e.g. water
B29C 45/1734
BPERFORMING OPERATIONS; TRANSPORTING
29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
CSHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
45Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor
17Component parts, details or accessories; Auxiliary operations
1703Introducing an auxiliary fluid into the mould
1734Nozzles therefor
B29C 45/174
BPERFORMING OPERATIONS; TRANSPORTING
29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
CSHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
45Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor
17Component parts, details or accessories; Auxiliary operations
1703Introducing an auxiliary fluid into the mould
174Applying a pressurised fluid to the outer surface of the injected material inside the mould cavity, e.g. for preventing shrinkage marks
B29K 2995/0063
BPERFORMING OPERATIONS; TRANSPORTING
29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
KINDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR ; MOULDS, ; REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
2995Properties of moulding materials, reinforcements, fillers, preformed parts or moulds
0037Other properties
0063Density
Applicants
  • ASAHI KASEI KOGYO KABUSHIKI KAISHA [JP/JP]; 2-6, Dojimahama 1-chome Kita-ku Osaka-shi Osaka 530, JP (AllExceptUS)
  • MATSUMOTO, Yuichi [JP/JP]; JP (UsOnly)
  • HORIKOSHI, Maki [JP/JP]; JP (UsOnly)
  • IMAI, Shoji [JP/JP]; JP (UsOnly)
Inventors
  • MATSUMOTO, Yuichi; JP
  • HORIKOSHI, Maki; JP
  • IMAI, Shoji; JP
Agents
  • KATAGIRI, Mitsuji; 312, Kyodo Building Akasaka 3-1, Akasaka 4-chome Minato-ku Tokyo 107, JP
Priority Data
6/18518515.07.1994JP
Publication Language English (EN)
Filing Language English (EN)
Designated States
Title
(EN) METHOD FOR THE NON-RESIN FLUID-ASSISTED INJECTION MOLDING OF A RESIN
(FR) PROCEDE DE MOULAGE PAR INJECTION D'UNE RESINE ASSISTE PAR UN FLUIDE NON RESINEUX
Abstract
(EN)
Disclosed is a method for the non-resin fluid-assisted injection molding of a resin to produce a shaped resin article having an improved surface finish, which comprises effecting an excess filling of a mold cavity of a sealed mold with a molten resin to form a molten resin mass having opposite, first and second surfaces respectively facing opposite inner walls of the mold cavity, wherein the excess filling is performed in a specific excess filling ratio which corresponds to an excess ratio of a resin by an amount corresponding to 30 to 90 % of a difference between the volume of the mold cavity and a volume exhibited by the resin in accordance with a shrinkage thereof when the molten resin filled in the mold cavity is cooled to a room temperature, and subsequently introducing a pressurized non-resin fluid into the mold cavity on a side of the first surface of the molten resin mass to thereby press the second surface of the molten resin mass against the cavity inner wall remote from the side of the introduction of the non-resin fluid. By the non-resin fluid-assisted injection molding method of the present invention, the occurrence of a sink mark on a front surface of a shaped resin article can be effectively prevented without causing the problem of occurrence of burrs (flashes).
(FR)
L'invention concerne un procédé de moulage par injection d'une résine assisté par un fluide non résineux, de façon à obtenir un article façonné en résine possédant une finition de surface améliorée. Ce procédé consiste à effectuer le remplissage en excès d'une cavité de moulage d'un moule scellé avec une résine fondue, de façon à obtenir une masse de résine fondue possédant une première et une deuxième surfaces opposées et respectivement orientées vers les parois intérieures opposées de la cavité de moulage. Le remplissage en excès s'effectue en fonction d'un rapport spécifique correspondant à un rapport excédentaire de résine selon une quantité correspondant à 30-90 % de la différence entre le volume de la cavité de moulage et un volume présenté par la résine après rétrécissement, quand la résine en fusion versée dans la cavité est refroidie à température ambiante. On introduit ensuite un fluide non résineux sous pression dans la cavité de moulage sur un côté de la première surface de la masse de résine fondue, de manière à appuyer la deuxième surface de ladite masse contre la paroi intérieure de ladite cavité, à distance du côté d'introduction du fluide non résineux. Ce procédé de moulage par injection assisté par un fluide non résineux permet d'empêcher l'apparition d'une marque de dépression sur la surface avant d'un article façonné en résine, sans provoquer de bavures.
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