Improvement of the mechanical properties of waterproofed gypsum boards with polydimethylsiloxanes
AssigneeKnauf Gips KG
InventorsHans WINTRICH, Janos LOTZ, Lothar SCHELLER, Simon GRÖNINGER
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Abstract
A waterproofed gypsum board and associated method are provided, featuring the use of a mixture of magnesium oxide and a gypsum crystal modifier for improving the resistance to sagging of the waterproofed gypsum board, in particular, in moist and warm climatic conditions.
Claims15
A waterproofed gypsum board, comprising:
- the gypsum board is waterproofed by means of at least one polysiloxane and includes magnesium oxide as catalyst for the polymerisation of the siloxane;
- the gypsum board having a gypsum crystal modifier;
- wherein the gypsum crystal modifier is effective during the production of the gypsum board in the rehydration from hemihydrate to dihydrate;
- and wherein the crystal modifier enhances the sag resistance of the gypsum board.
A method for producing a waterproofed gypsum board, comprising the following steps:
- a) producing a slurry by mixing one or more calcium sulfate phases capable of setting,
- water,
- siloxane,
- magnesium oxide and
- a gypsum crystal modifier, wherein the crystal modifier enhances the sag resistance of the gypsum board;
- and
- b) shaping the mixture.
A use of a mixture of magnesium oxide and a gypsum crystal modifier selected from bivalent heavy metal salts, metal silicates, borates and mixtures thereof for improving the resistance to sagging of gypsum boards, in particular in moist and warm climatic conditions.
Dependencies are inferred from the claim text.