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 adjustment in terms of retarding effect, but in terms of comprehensive application performance of gypsum products, especially gypsum The strength loss of the product is not satisfactory

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
Effect test

Embodiment 1

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

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

[0051] The first step: prepare the intermediate product of gypsum retarder

[0052]React diacid or acid anhydride:ammonia-containing substances at a molar ratio of 1:1~1:1.5 at a temperature of 50~80°C for 1~2 hours, then raise the temperature to 150~190°C for 10~60min, cool to At room temperature, an intermediate product is formed;

[0053] Step 2: Prepare gypsum retarder

[0054] a. Preparation of the retarder aqueous solution: take the intermediate product...

Embodiment 2

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

[0066] The first step: prepare the intermediate product of gypsum retarder

[0067] a1. Direct thermal shrinkage and polymerization of L-aspartic acid at a temperature of 150-250°C 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°C 10 to 60 minutes, then cooled to room temperature, adding ethanol to the solution to form a precipitate, standing and filtering to obtain the intermediate product;

[0069] Wherein: the catalyzer is phosphoric acid, hydrochloric acid, sulfuric acid, and the mol ratio of catalyzer: L-aspartic acid is 0.05~0.3:1;

[0070] The solvent is sulfolane, dimethyl sulfolane, propylene carbonate, b...

Embodiment 3

[0089] A kind of application of the gypsum retarder obtained by the preparation method described in embodiment 1 and embodiment 2, the content in embodiment 1 and embodiment 2 content should also be the content of this embodiment, wherein,

[0090] The setting retarder obtained by the preparation method described in Example 1 and Example 2 is added to the gypsum to prolong the setting time of the gypsum and reduce the loss of strength of the gypsum hardened body. 0.5%, the retarder is calculated on dry matter.

[0091] The retarder used in the application has a weight average molecular weight in the range of 2000-30000, preferably 3500-10000, more preferably 4000-9000.

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

[0093] The amount of retarder used in gypsum retarder is calculated by weight percentage, and the re...

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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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