(19)
(11) EP 0 459 486 A3

(12) EUROPEAN PATENT APPLICATION

(88) Date of publication A3:
03.02.1993 Bulletin 1993/05

(43) Date of publication A2:
04.12.1991 Bulletin 1991/49

(21) Application number: 91108870.6

(22) Date of filing: 29.05.1991
(51) International Patent Classification (IPC)5: B22C 7/00, B22C 7/02
(84) Designated Contracting States:
DE FR GB SE

(30) Priority: 30.05.1990 JP 138328/90
30.05.1990 JP 138329/90
08.06.1990 JP 148613/90

(71) Applicant: NKK CORPORATION
Tokyo (JP)

(72) Inventors:
  • Nishio, Hiroaki
    Chiyoda-ku, Tokyo (JP)
  • Sato, Michitaka
    Chiyoda-ku, Tokyo (JP)
  • Takase, Akira
    Chiyoda-ku, Tokyo (JP)
  • Kato, Akira
    Chiyoda-ku, Tokyo (JP)

(74) Representative: Grünecker, Kinkeldey, Stockmair & Schwanhäusser Anwaltssozietät 
Maximilianstrasse 58
80538 München
80538 München (DE)


(56) References cited: : 
   
       


    (54) Pattern for manufacturing mold


    (57) A pattern for manufacturing a mold consisting essentially of a flexible thin bag made of a material (1), which is impermeable with regard to the fluid contained therein and the material forming the mold (9), which is resistant to both of the fluid and the material forming the mold, and which has an elastic modulus in tension of 1 to 200 kg/mm², and the fluid contained therein (6), and a process for preparing a mold using the same, a process for preparing a collapsable pattern which comprises cooling to solidify an agglomerate of water-absorbable swellable organic polymer particles containing an aqueous solution into a prescribed form, and a process for preparing a water-soluble pattern which comprises filling a melted blend consisting essentialy of 5 to 95 wt. % of urea and 95 to 5 wt. % of a carbamate ester compatible with urea into a mold, and cooling to solidify it. According to the above means, the molds can be formed without broken at a pressure lower than 10 kg/cm², and the working environment problem caused by ammonia gas evolution is not present.






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