High water reduction powder preparation for dry mortar

Patent metadata

Field	Value
Publication number	US-12391616-B2
Application number	US-202017598349-A
Country	US
Kind code	B2
Filing date	Mar 26, 2020
Priority date	Mar 26, 2019
Publication date	Aug 19, 2025
Grant date	Aug 19, 2025

Abstract

PCE-type copolymers in powder form can be obtained by spry-drying and are easily re-dispersed in water. The fineness and the anti-caking properties of said PCE-type copolymers in powder form, as well as their water reduction potential and influence on slump life are improved. A production process of said PCE-type copolymers in powder form is by a spray-drying method, and PCE-type copolymers can be used for the improvement of mineral binder compositions and especially dry mortars.

First claim

The invention claimed is:

1. A process for the production of a powdered copolymer P, said process comprising the steps of
i) preparing an aqueous copolymer solution comprising 30-99 w %, based on the total weight of said aqueous solution, of a PCE-type copolymer comprising
a) a molar parts of a structural unit S1 of formula I

b) b molar parts of a structural unit S2 of formula II

c) c molar parts of a structural unit S3 of formula III

and d) d molar parts of a structural unit S4 of formula IV

wherein
each M independently from each other represents H+, an alkali metal ion, an alkaline earth metal ion, a di- or trivalent metal ion, an ammonium ion or an organic ammonium group,
each R u independently from each other represents hydrogen or a methyl group,
each R v independently from each other represents hydrogen or COOM,
m is 0, 1, 2 or 3,
p is 0 or 1,
each R 1 and each R 2 independently from each other represents
C 1 - to C 20 -alkyl,
-cycloalkyl,
-alkylaryl or
for -[AO] n —R 4 , where
A represents a C 2 - to C 4 -alkylene,
R 4 represents H, C 1 - to C 20 -alkyl, -cyclohexyl or -alkylaryl, and
n is an integer in the range of from 2-350,

each R 3 independently of the others represents NH 2 , —NR 5 R 6 , —OR 7 NR 8 R 9 ,
wherein R 5 and R 6 independently from each other stand for
C 1 - to C 20 -alkyl, -cycloalkyl
alkylaryl or -aryl,
or for a hydroxyalkyl- or acetoxyethyl-(CH 3 —CO—O—CH 2 —CH 2 —) or
hydroxyisopropyl-(HO—CH(CH 3 )—CH 2 —) or acetoxyisopropyl group (CH 3 —CO—O—CH(CH 3 )—CH 2 —);

or R 5 and R 6 together form a ring of which the nitrogen is part, to form a morpholine or imidazoline ring,
R 7 is a C 2 -C 4 -alkylene group,
each R 8 and R 9 independently from each other represent C 1 - to C 20 -alkyl,
-cycloalkyl, -alkylaryl,
-aryl or a hydroxyalkyl group,

and a, b, c and d stand for the molar parts of the structural units S1, S2, S3 and S4, with a/b/c/d having values in the following ranges: (0.1-0.9)/(0.1-0.9)/(0-0.8)/(0-0.8), with the provision that a+b+c+d is equal to 1,
ii) adding a base to adjust the pH of the aqueous copolymer solution to at least 10,
iii) adding 0.01 to 5 w %, based on the weight of the aqueous copolymer solution, of at least one additive selected from anti-caking agents and/or anti-oxidants,
iv) spray-drying the aqueous copolymer solution to obtain a powder, and
v) optionally sieving.

2. A process according to claim 1 wherein the powdered copolymer P that is obtained after spray-drying the aqueous copolymer solution has a particle size distribution with a D90 of <250 μm, a D10 of <60 μm, and a D50 of between 70-130 μm.

3. A process according to claim 1 wherein
each R 1 and R 2 in the powdered copolymer P independently from each other represents -[AO] n —R 4 ,
each R 4 independently from each other is selected from H or CH 3 , and
n is an integer in the range of from 50-115.

4. A process according to claim 1 wherein the ratio of a/b in the powdered copolymer P is in the range of from 0.5/1 and 15/1.

5. A process according to claim 1 , wherein the PCE-type copolymer in step i) is prepared by a radical polymerization process.

6. A process according to claim 1 , wherein the base added in step ii) is chosen from LiOH, NaOH, KOH, Mg(OH) 2 , Ca(OH) 2 or mixtures thereof.

7. A process according to claim 6 , wherein
the base added in step ii) is Ca(OH) 2 and
the pH of the aqueous copolymer solution is between 10 and 14.

8. A process according to claim 1 , wherein step iv) is performed at a spray-dry inlet temperature of not more than 150° C.

9. The process according to claim 1 , wherein the base added in step ii) is added in an amount effective to adjust the pH of the aqueous copolymer solution to at least 11.

Assignees

• Sika Tech Ag

Inventors

• Yu Chao
• Zhu Jiali
• Liu Jianghong
• Chen Lin

Classifications

• C08J2351/08

  grafted on to macromolecular compounds obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds · CPC title

• C08J3/122

  Pulverisation by spraying · CPC title

• C08F290/142

  Polyethers · CPC title

• C04B40/0042

  Powdery mixtures · CPC title

• C04B28/02

  containing hydraulic cements other than calcium sulfates · CPC title