Calcium carbonate pigment for heat-sensitive recording paper, process for preparing same, coating composition for heat-sensitive recording paper and heat-sensitive recording paper

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EP 0 456 413 A3

(12)	EUROPEAN PATENT APPLICATION

(88)	Date of publication A3:
	16.09.1992 Bulletin 1992/38

(43)	Date of publication A2:
	13.11.1991 Bulletin 1991/46

(21)	Application number: 91303976.4

(22)	Date of filing: 02.05.1991

(51)	International Patent Classification (IPC)⁵: C09C 1/02, B41M 5/30, B41M 5/40

(84)	Designated Contracting States:
	DE FR GB

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Priority:

11.05.1990 JP 122517/90

(71)	Applicant: SHIRAISHI CENTRAL LABORATORIES, CO. LTD.
	Amagasaki-shi, Hyogo-ken (JP)

(72)	Inventors:
	Tsukisaka, Ryogo Takarazuka-shi, Hyogo-ken (JP) Kondo, Satoshi Amagasaki-shi, Hyogo-ken (JP) Kaneguchi, Toshio Kobe-shi, Hyogo-ken (JP) Sakamoto, Atsushi Yao-shi, Osaka-fu (JP)

(74)	Representative: Ede, Eric et al
	Fitzpatricks, 4 West Regent Street Glasgow G2 1RS, Scotland Glasgow G2 1RS, Scotland (GB)

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References cited: :

(54)	Calcium carbonate pigment for heat-sensitive recording paper, process for preparing same, coating composition for heat-sensitive recording paper and heat-sensitive recording paper

(57) Disclosed are a calcium carbonate pigment for heat-sensitive recording paper, the pigment having a BET specific surface area of about 17 to about 55 m²/g, an oil absorption of about 90 to about 220 ml/100 g as determined by the Ogura method and a surface acidity of solid substantially represented by the following equation (Z):

wherein x is a BET specific surface area (m²/g) and y is a surface acidity of solid (µmol/g); a process for preparing the pigment; coating compositions comprising said pigment each for forming an intermediate layer of heat-sensitive recording layer, and for a heat-sensitive recording layer thereof: and heat-sensitive recording papers obtained by application of the coating compositions.

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