Preparation method and application of gypsum retarder

A gypsum retarder and a technology of retarder, which are applied in the field of preparation of gypsum retarder, can solve the problems of unsatisfactory strength loss of gypsum products, and achieve the effects of reducing strength loss and water demand.

Active Publication Date: 2014-08-13
BEIJING BUILDING MATERIALS ACADEMY OF SCI RES +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The currently commonly used gypsum retarders such as citric acid, tartaric acid, acrylic acid, phosphate, bone glue and protein hydrolyzate can achieve better setting time adjustm

Method used

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  • Preparation method and application of gypsum retarder
  • Preparation method and application of gypsum retarder
  • Preparation method and application of gypsum retarder

Examples

Experimental program
Comparison scheme
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Example Embodiment

[0048] Example 1:

[0049] A method for preparing a gypsum retarder. The gypsum retarder is prepared from a diacid or anhydride substance and an ammonia-containing substance, and the molar ratio of the diacid or anhydride: ammonia-containing substance is 1:1~ 1:1.5; the diacid or anhydride substance includes maleic anhydride or maleic acid or fumaric acid; the ammonia-containing substance includes ammonium carbonate or ammonium bicarbonate or ammonia;

[0050] The specific steps of the preparation method are:

[0051] Step 1: Preparation of intermediate product of gypsum retarder

[0052] The diacid or acid anhydride: ammonia-containing substance is reacted at a temperature of 50-80℃ for 1~2 hours at a molar ratio of 1:1~1:1.5, then heated to 150~190℃ for 10~60min, and cooled to At room temperature, an intermediate product is formed;

[0053] Step 2: Preparation of gypsum retarder

[0054] a. Preparation of the retarder aqueous solution: take the intermediate product, add sodium hydrox...

Example Embodiment

[0064] Example 2:

[0065] A preparation method of a gypsum retarder, the gypsum retarder is prepared from L-aspartic acid, and the specific steps of the preparation method are:

[0066] Step 1: Preparation of intermediate product of gypsum retarder

[0067] a1. Directly heat shrink and polymerize L-aspartic acid at a temperature of 150~250℃ to form an intermediate product;

[0068] a2. Dissolve L-aspartic acid in a solvent to form an L-aspartic acid solution with a concentration of 10-50%, add a catalyst to the L-aspartic acid solution, and react at a temperature of 130-180℃ 10 to 60 minutes, then cool to room temperature, add ethanol to the solution to form a precipitate, and filter to obtain the intermediate product;

[0069] Wherein: the catalyst is phosphoric acid, hydrochloric acid, and sulfuric acid, and the molar ratio of the catalyst: L-aspartic acid is 0.05 to 0.3:1;

[0070] The solvent is sulfolane, dimethyl sulfolane, propylene carbonate, butylene carbonate, and diphenyl ca...

Example Embodiment

[0088] Example 3:

[0089] An application of the gypsum retarder obtained by the preparation methods described in Example 1 and Example 2. The content of Example 1 and the content of Example 2 should also be the content of this example, in which,

[0090] The retarder obtained by the preparation methods described in Example 1 and Example 2 was added to gypsum to extend the setting time of gypsum and reduce the strength loss of hardened gypsum. The amount of retarder added is 0.01 to the total weight of gypsum. 0.5%, the retarder is based on dry matter.

[0091] The weight average molecular weight of the retarder used in the application is in the range of 2000 to 30,000, preferably 3500 to 10,000, more preferably 4000 to 9000.

[0092] In an embodiment, the retarder can be used in the form of an aqueous solution or a fine powder, and the aqueous solution preferably has a concentration range of 10%-50%, more preferably 30%-40%.

[0093] The amount of retarder used for gypsum retarder is ...

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Abstract

The invention discloses a preparation method and an application of a gypsum retarder. The gypsum retarder is prepared from a diacid or anhydride material and an ammoniacal material or L-aspartic acid; the retarder prepared by use of the preparation method is added to gypsum so as to increase the setting time of a gypsum building material and reduce the strength loss of a hardened gypsum body. The retarder is a water-soluble amino acid degradable polymer, has excellent biodegradability and is a green and environment-friendly polymer material. The molecular structure of the retarder contains a large number of groups such as carboxyl, carbonyl and acyl, and the groups can be combined with Ca<2+> into complexes so that the dissolution velocity of the gypsum can be reduced, the diffusion of Ca<2+> to gypsum crystals can be restricted and hydration of gypsum particles can be hindered, and therefore, the retarding effect of the retarder is realized. Meanwhile, the strength loss caused by structural degradation of gypsum holes due to a high water-gypsum ratio is reduced.

Description

technical field [0001] The invention relates to the production of gypsum building materials, in particular to a preparation method and application of a gypsum retarder. Background technique [0002] As a building material, gypsum has many excellent characteristics, such as light weight, good thermal insulation performance and sound absorption performance of hardened body, slight volume expansion when hardened, smooth surface of hardened body, no cracking when dry, good decoration, good processability, Low production energy consumption and other advantages. As an excellent green building material, gypsum is widely used in plastering plaster, plastering gypsum, plaster products and other decorative parts. [0003] In practical application, the setting time of gypsum material is short after mixing with water, and it can lose fluidity in a few minutes, which cannot meet the requirements of normal construction. Usually, retarders are added to the gypsum system to adjust the...

Claims

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Application Information

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IPC IPC(8): C04B24/12C08G73/10C04B103/22
Inventor 战佳宇李万民郝利炜顾军杜春杰
Owner BEIJING BUILDING MATERIALS ACADEMY OF SCI RES
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