EP 1967649 A1 20080910 - Concentrated aqueous gypsum suspensions and their use in paper production
Title (en)
Concentrated aqueous gypsum suspensions and their use in paper production
Title (de)
Konzentrierte wässrige Gipssuspensionen und ihre Verwendung bei der Papierherstellung
Title (fr)
Suspensions concentrées de gypse aqueux et leur utilisation dans la fabrication du papier
Publication
Application
Priority
IT VA20070018 A 20070216
Abstract (en)
Process for the preparation of paper characterised by the fact that an aqueous gypsum suspension having Brookfield viscosity at 25°C and 100 rpm comprised between 100 and 1,000 mPa·s and containing from 60 to 85% by weight of gypsum in the form of calcium sulphate dihydrate (Ca 2 SO 4 .2H 2 O) is added to the cellulose aqueous suspension used for the production of paper, the aqueous gypsum suspension containing from 0.1 to 2% by weight of an acrylic sulphonated polymer, or of an acrylic carboxylated polymer or of a polynaphthalene sulphonate, and from 0.1 to 1.0% by weight of an organic polyphosphonate.
IPC 8 full level
D21H 17/67 (2006.01)
CPC (source: EP)
D21H 17/67 (2013.01); D21H 17/10 (2013.01); D21H 17/37 (2013.01); D21H 19/38 (2013.01); D21H 19/44 (2013.01)
Citation (applicant)
- IT VA20060044 A 20060718
- EP 0056200 B1 19870923
- EP 1713568 A1 20061025 - BOZZETTO GIOVANNI SPA [IT]
Citation (search report)
- [DY] US 2004187741 A1 20040930 - LIU QINGXIA [US], et al
- [Y] DE 4027237 A1 19920305 - GYPSUM RESEARCH [CH]
- [A] DE 3203067 A1 19820826 - KEMIRA OY [SE]
- [A] US 3645677 A 19720229 - AKAZAWA HAKUICHI, et al
- [A] GB 2173781 A 19861022 - BEROL KEMI AB
- [A] US 5236989 A 19930817 - BROWN ALAN J [US], et al
- [A] WO 9208755 A1 19920529 - ECC AMERICA INC [US]
Designated contracting state (EPC)
AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MT NL NO PL PT RO SE SI SK TR
Designated extension state (EPC)
AL BA MK RS
DOCDB simple family (publication)
DOCDB simple family (application)
EP 08100527 A 20080116; IT VA20070018 A 20070216