METHOD FOR REDUCING AGGLOMERATION IN GYPSUM PLASTER OR FILLING COMPOSITIONS COMPRISING CELLULOSE ETHER

• US 20150122152A1
• Filed: 12/04/2012
• Published: 05/07/2015
• Est. Priority Date: 12/09/2011
• Status: Active Grant

• Current Assignee: Dow Global Technologies LLC (Dow, Inc.)
• Original Assignee: Dow Global Technologies LLC (Dow, Inc.)
• Inventors: Neubauer, Joerg, Scharlemann, Sonja
• Granted Patent: US 10,457,600 B2
• Time in Patent Office: Days
• US Class Current: 106/652
• CPC Class Codes: C04B 11/00 Calcium sulfate cements
• CPC Class Codes: C04B 16/02 Cellulosic materials cellulosic waste materials, e.g. sawdust, rice husks, C04B18/24
• CPC Class Codes: C04B 16/04 Macromolecular compounds C04B16/02 takes precedence
• CPC Class Codes: C04B 2111/00198 Characterisation or quantities of the compositions or their ingredients expressed as mathematical formulae or equations
• CPC Class Codes: C04B 24/14 Peptides; Proteins; Derivatives thereof
• CPC Class Codes: C04B 24/383 Cellulose or derivatives thereof
• CPC Class Codes: C04B 28/14 containing calcium sulfate cements gypsum-paper plates E04C
• CPC Class Codes: C04B 40/0039 Premixtures of ingredients
• CPC Class Codes: C04B 40/0608 Dry ready-made mixtures, e.g. mortars at which only water or a water solution has to be added before use

Abstract

The present invention relates to a method for providing modified gypsum plaster or filling compositions having reduced agglomeration in comparison to gypsum plaster or filling compositions comprising cellulose ether in a specific amount from 0.1 to 1.0 weight percent, based on the total dry weight of said composition. Also provided are dry mortars comprising cellulose ether, gelatin and gypsum for use in such methods, and gypsum-free mixtures comprising cellulose ether and gelatin which may be added to gypsum binder for use a for use in such methods.

Claims

1. A method for providing a modified gypsum plaster or filling composition having reduced agglomeration in comparison to a gypsum plaster or filling composition comprising a water soluble cellulose ether in a specified amount X, where the specified amount is from 0.1 to 1.0 weight percent based on the total dry weight of said composition components, said method comprising:

a) forming a dry mortar comprising gypsum binder;

water soluble cellulose ether in an amount of X minus Y; and

gelatin in an amount Y, wherein Y is from 0.02X to 0.30X; and

b) combining said dry mortar with water to form a modified gypsum plaster or filling composition.

2. The method according to claim 1, wherein said cellulose ether is an alkylhydroxyalkylcellulose, a hydroxyalkyl cellulose, an alkyl cellulose or a mixture thereof.

3. The method according to claim 2, wherein said alkylhydroxyalkylcellulose is selected from a methylhydroxyethylcellulose (MHEC), an ethylhydroxyethylcellulose (EHEC), a methyl hydroxypropylcellulose (MHPC), a methylethylhydroxyethylcellulose (MEHEC), a methylhydroxy-ethylhydroxypropylcellulose (MHEHPC) and mixtures thereof.

4. The method according to claim 2, wherein, when said cellulose ether is an alkylhydroxyalkylcellulose, said alkylhydroxyalkylcellulose has a DS(alkyl) of from >

1 to 1.99 and an MS (hydroxyalkyl) of from 0.01 to <

1, provided that the sum total of DS plus MS is less than or equal to 2.0.

5. The method according to claim 1, wherein said cellulose ether has a median particle diameter DOP (50,3) of from 25 μ

m to 45 μ

m.

6. The method according to claim 1, wherein said cellulose ether has a median particle diameter of the equivalent particle circle EQPC (50,3) of from 65 μ

m to 100 μ

m.

7. The method according to claim 1, wherein said cellulose ether has a viscosity grade of from 1000 to 500,000 mPa s, measured as a 2% aqueous solution at 20°

C. using an Ubbelohde tube viscometer.

8. The method according to claim 1, wherein the total amount of cellulose ether and gelatin present in said modified gypsum plaster or filling composition is from 0.1 to 0.5 weight percent, based on the total dry weight of said composition.

9. The method according to claim 1, wherein said dry mortar comprises gypsum in an amount not less than 10 weight percent, based on the total dry weight of its components.

10. A dry mortar comprising gypsum binder, cellulose ether and gelatin for use in a method according to any of the preceding claims, wherein said dry mortar comprises 0.1 to 1.0 weight percent, based on the total weight of said dry mortar, of a mixture consisting of cellulose ether and gelatin, wherein the weight ratio of cellulose ether to gelatin is from 49:

1 to 7;

3.

11. A gypsum-free mixture comprising cellulose ether and gelatin, which may be added to gypsum binder for use in the method according to claim 1, wherein the weight ratio of cellulose ether to gelatin is from 49:

1 to 7;

3.