Slurry for forming interlayer for collapsible core, method of production of collapsible core using same and collapsible core produced thereby

(19)

(11)

EP 0 412 761 A3

(12)	EUROPEAN PATENT APPLICATION

(88)	Date of publication A3:
	20.05.1992 Bulletin 1992/21

(43)	Date of publication A2:
	13.02.1991 Bulletin 1991/07

(21)	Application number: 90308647.8

(22)	Date of filing: 06.08.1990

(51)	International Patent Classification (IPC)⁵: B22C 1/16, B22C 3/00

(84)	Designated Contracting States:
	DE FR GB IT

(30)

Priority:

07.08.1989 JP 204159/89

(71)	Applicant: RYOBI LTD.
	Fuchu-shi, Hiroshima-ken (JP)

(72)	Inventors:
	Egoshi, Yoshiaka, c/o Ryobi Limited Fuchu-shi, Hiroshima-ken (JP) Sasaki, Hideto, c/o Ryobi Limited Fuchu-shi, Hiroshima-ken (JP)

(74)	Representative: Fry, Alan Valentine
	FRY HEATH & SPENCE The Old College 53 High Street Horley Surrey RH6 7BN Horley Surrey RH6 7BN (GB)

(56)

References cited: :

(54)	Slurry for forming interlayer for collapsible core, method of production of collapsible core using same and collapsible core produced thereby

(57) An collapsible core (1) is formed in such a manner that a sand core (1a) is dipped into an acidic suspension having a pH of 5.2 to 6.8 to form an interlayer (2), that the interlayer (2) is coated with an outer layer (3) and that both layers (2, 3) are heat-cured simultaneously.

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