Surface retarder formulation and method for replicating an acid etch or sand blast aspect on cementitious material

Patent metadata

Field	Value
Publication number	US-2021061721-A1
Application number	US-201916960532-A
Country	US
Kind code	A1
Filing date	Jan 8, 2019
Priority date	Jan 8, 2018
Publication date	Mar 4, 2021
Grant date	—

Abstract

Disclosed are surface retarder composition and method for etching cementitious materials which achieve a desirable light “acid etch” look without using muriatic (hydrochloric) acid or sand blasting, removing the human health and environmental concerns. Formulations in accordance with embodiments disclosed herein are easier to remove from formwork or molds after demolding than conventional retarder paints. Surface retarders prevent the hydration of cement particles, which allows the uncured layer of paste next to the form to be removed such as by washing with water or other fluids, or by brushing, revealing aggregates. Also disclosed are molded cement and concrete materials or articles exhibiting such light etch.

First claim

What is claimed is:

1 . A surface retarder composition comprising a resin or polymer having an acid number of greater than 100 mgKOH/g of resin or polymer,
a. an aliphatic solvent that is a poor solvent for said resin; b. at least one surface retarder active agent having solubility and cement binding values, which, when plotted with solubility value on the x-axis and cement binding value on the y-axis and displayed in log scale, lie closer to the origin than the line y=5000e −0.236x .

2 . The surface retarder of claim 1 , wherein the solvent is chosen from mineral spirits, white spirits, and VM&P naptha.

3 . The surface retarder of claim 1 , wherein the solvent is chosen from odorless mineral spirits.

4 . The surface retarder of claim 1 wherein the at least one surface retarder active agent has solubility and cement binding values, which, when plotted with solubility on the x-axis and cement binding on the y-axis, lie above the line y=200e −0.236x .

5 . The surface retarder of claim 1 , wherein the at least one surface retarder active agent comprises at least one organic diacid compound chosen from oxalic acid, D,L-tartaric acid, citraconic acid, glutaric acid, phthalic acid, mesaconic acid, methylmalontic acid, adipic acid, succinic acid, itaconic acid, and combinations thereof.

6 . The surface retarder of claim 1 , wherein the at least one surface retarder active agent is chosen from oxalic acid, D,L-tartaric acid, citraconic acid, glutaric acid, aconitic acid, boric acid, and combinations thereof.

7 . The surface retarder of claim 1 , wherein the at least one surface retarder active agent comprises at least one organic diacid compound that is a co-crystallized 1:1 mixture of L-tartaric and D-tartaric acid.

8 . The surface retarder of claim 1 , wherein the resin is a dimerized or polymerized gum rosin.

9 . The surface retarder of claim 1 , wherein the resin is a plant-based resin.

10 . The surface retarder of claim 1 , wherein the at least one surface retarder active agent is at least one organic diacid compound, which, when plotted with solubility on the x-axis and oxygen-to-carbon ratio on the y-axis, lies closer to the origin than the line y=−0.075x+3.2.

11 . The surface retarder of claim 1 wherein the at least one surface retarder active agent is at least one organic diacid compound having solubility and oxygen-to-carbon ratio values, which, when plotted with solubility on the x-axis and oxygen-to-carbon ratio on the y-axis and displayed in log scale, lies further from the origin than the line y=−0.075x+2.

12 . A concrete article with an acid-like etch made by using a surface retarder in accordance with claim 1 .

13 . A method of etching the surface of a cementitious composition, comprising:
providing a cementitious composition having a surface to be etched, said cementitious composition comprising a hydratable cement binder and water; said cementitious composition further comprising at least one aggregate; providing a mold; applying a surface retarding composition to said mold, said surface retarding composition comprising a resin having an acid number of greater than 100 mgKOH/g of resin, an aliphatic solvent that does not dissolve the resin fully, and at least one surface retarder active agent having solubility and cement binding values, which, when plotted with solubility on the x-axis and cement binding on the y-axis displayed in log scale, lies closer to the origin than the line y=5000e −0.236x ; introducing said cementitious composition to said mold in an uncured state and allowing said cementitious composition to cure; removing the cured cementitious composition from said mold; and removing a portion of the surface of said cementitious composition coated with said surface retarding composition, thereby revealing an etched portion in said cementitious composition comprising said at least one aggregate.

14 . The method of claim 13 , wherein the at least one surface retarder active agent having solubility and cement binding values, which, when plotted with solubility on the x-axis and cement binding on the y-axis displayed in log scale, lies further from the origin than the line y=200e −0.236x .

15 . The method of claim 13 , wherein said at least one aggregate is chosen from sand, crushed gravel, stone and mixtures thereof.

16 . The method of claim 13 , wherein said coating is removed with a jet of pressurized water.

17 . The method of claim 13 , wherein said cementitious composition comprises a hydratable cementitious binder comprising Portland cement, masonry cement, or mortar cement.

18 . The method of claim 13 , wherein said surface retarder composition is applied to said mold by spraying.

19 . The method of claim 13 , wherein said surface retarder composition is applied to said mold by brushing.

20 . The method of claim 13 , wherein said at least one surface retarder active agent is chosen from oxalic acid, D,L-tartaric acid, citraconic acid, glutaric acid, aconitic acid, boric acid, and combinations thereof.

21 . A method of etching the surface of a cementitious composition, comprising:
providing a cementitious composition having a surface to be etched, said cementitious composition comprising a hydratable cement binder and water; said cementitious composition further comprising at least one aggregate; providing a mold; applying a surface retarding composition to said mold, said surface retarding composition consisting essentially of a resin having an acid number of greater than 100 mgKOH/g of resin, an aliphatic solvent that does not dissolve the resin fully, and at least one organic diacid compound which binds cations and which has solubility and oxygen-to-carbon values, which, when plotted with solubility on the x-axis and oxygen-to-carbon ratio on the y-axis, lies closer to the origin than the line y=−0.075x+3.2; introducing said cementitious composition to said mold in an uncured state and allowing said cementitious composition to cure; removing the cured cementitious composition from said mold; and removing a portion of the surface of said cementitious composition coated with said surface retarding composition, thereby revealing an etched portion in said cementitious composition comprising said at least one aggregate.

22 . The method of claim 21 , wherein said at least one organic diacid compound is chosen from oxalic acid, D,L-tartaric acid, citraconic acid, glutaric acid, or combination thereof; or combinations thereof.

23 . The method of claim 21 , wherein said at least one aggregate is chosen from sand, crushed gravel, stone, and mixtures thereof.

Assignees

• Gcp Applied Tech Inc

Inventors

• Burns Elizabeth G
• Geary David
• Vincent Dany
• Bui Huy The

Classifications

• C04B41/72 Primary

  involving the removal of part of the materials of the treated articles, e.g. etching · CPC title

• C04B40/0295 Primary

  Inhomogeneous curing or hardening, e.g. accelerated curing of surface regions of a concrete article; Influencing the setting or hardening process to generate physical or mechanical effects, e.g. to create cracks · CPC title

• C04B41/009

  characterised by the material treated · CPC title

• C04B2103/20

  Retarders · CPC title

• C04B41/5323

  to make grain visible, e.g. for obtaining exposed aggregate concrete · CPC title