A retarder for delaying the setting time of building gypsum and preparation method thereof

Abstract

The invention discloses a retarder for delaying the setting time of building gypsum and a preparation method thereof. The invention uses food-grade organic protein amino acid components as raw materials, introduces a variety of polycarboxyl organic acids and cross-linking components, performs high-temperature condensation, and controls the protein molecular weight by controlling pH. The polycarboxyl organic acid is also used as an effective retarding component, thereby effectively improving the retarding performance and stability of the retarder. The invention has the advantages of simple process, low energy consumption, low cost, and no pollution.

Description

Technical Field

[0001] The invention relates to the technical field of building gypsum additives, in particular to a retarder for delaying the setting time of building gypsum and a preparation method thereof. Background Art

[0002] At present, building gypsum is widely used in plastering construction, painting and the manufacture of various gypsum products. However, the rapid setting time greatly affects the application. Therefore, gypsum retarding is an indispensable technology that can provide gypsum with plastic applicability with controllable time.

[0003] The common synthesis method in the market is to prepare protein gypsum retarders by processing by-product protein powder, bone glue, penicillin mycelium, leather scraps and other waste materials whose main components are proteins as raw materials. During processing, the above protein-containing wastes are generally hydrolyzed at high temperature by catalysts such as inorganic acids such as hydrochloric acid or sulfuric acid, strong bases such as calcium hydroxide or sodium hydroxide, and their molecular weights are adjusted to a suitable range, and then the acid, alkali or salt formed by neutralization is removed to obtain protein retarders. However, this process has strict requirements on the harsh production environment, and the raw materials often produce a lot of unpleasant odors, waste gas and wastewater and other environmental problems during the production process, and also generate high production costs and energy consumption. Summary of the invention

[0004] The main technical problem solved by the present invention is how to reduce the complexity of the production process of the product, save costs and reduce the environmental pollution caused by various protein wastes in the production process.

[0005] A technical solution adopted by the present invention is: Provided is a retarder for delaying the setting time of building gypsum and a preparation method thereof, the steps comprising: (1) adding a small molecule polybasic carboxyl organic compound and water into a reaction kettle, heating to 60-80° C., stirring and dissolving to obtain a mixed solution; wherein the weight portion of the small molecule polybasic carboxyl organic compound is 75-90 parts, and the weight portion of water is 10-25 parts; the small molecule polybasic carboxyl compound is one or two of fumaric acid, citric acid, tartaric acid, succinic anhydride, and acetic anhydride; (2) adding 45-90 parts by weight of food-grade protein powder and 0.02-0.1 parts by weight of a transition metal catalyst to a mixed solution, then heating the solution to 70-110° C., stirring the solution to obtain a stock solution, then lowering the temperature of the stock solution to room temperature, and adding 35-55 parts by weight of water to obtain a diluted stock solution; wherein the food-grade protein powder comprises one or more of glycine, glutamic acid, lysine, aspartic acid, and aminobutyric acid; and the weight of the food-grade protein powder is 60-100% of the total weight of the small molecule polycarboxyl organic matter; (3) Add 30-50 parts by weight of water and 8-15 parts by weight of a cross-linking agent into the reactor, and heat it to 40-60°C. Then slowly add the diluted stock solution and pH adjuster into the reactor to keep the pH of the solution at a weak alkaline level. After completion, keep the temperature constant. (4) After the solution obtained in step (3) is cooled to room temperature, it is powdered and dried in a centrifugal spray tower to obtain a polycarboxyl-modified opal gypsum retarder.

[0006] In a preferred embodiment of the present invention, in step (1), the small molecule polycarboxyl compound comprises two components, one component is succinic anhydride, the weight proportion of which is 40 to 60 parts, and the other component is one of fumaric acid, citric acid, tartaric acid, and acetic anhydride, the total weight proportion of which is 40 to 60 parts.

[0007] In a preferred embodiment of the present invention, in step (2), the transition metal catalyst is one of Pt and Zn based catalysts.

[0008] In a preferred embodiment of the present invention, in step (2), the reaction temperature of the mixture of food-grade protein powder and transition metal catalyst is 90-100°C, the stirring time is 30-90 minutes, and then the temperature is reduced to 30-50°C.

[0009] In a preferred embodiment of the present invention, the components of the food-grade protein powder and their weight proportions include 90-110 parts of glycine, 75-90 parts of lysine and 0-10 parts of other protein powders.

[0010] In a preferred embodiment of the present invention, in step (3), the cross-linking agent is one of glutaraldehyde, boric acid, sodium trimetaphosphate, N,N'-methylenebisacrylamide and ethylene glycol diacrylate, glutaminase, tannic acid and phytic acid.

[0011] In a preferred embodiment of the present invention, in step (3), the diluted stock solution and pH adjuster are added dropwise into the reaction kettle.

[0012] In a preferred embodiment of the present invention, in step (3), the pH adjuster is one of a sodium hydroxide solution and a calcium hydroxide solution.

[0013] In a preferred embodiment of the present invention, in step (3), the dropping time is 30-60 min, the solution pH value is 8-10, the insulation temperature is 40-60° C., and the insulation time is 30-60 min.

[0014] A retarder for delaying the setting time of building gypsum is prepared by the above preparation method.

[0015] The beneficial effects of the present invention are as follows: using food-grade organic protein amino acid components as raw materials, introducing a variety of polycarboxyl organic acids and cross-linking components, condensing at high temperature and controlling pH to regulate the protein molecular weight, and polycarboxyl organic acids also serving as effective retarding components, thereby effectively improving the retarding performance and stability of the retarder, and the process is simple, low in energy consumption, low in cost, and pollution-free. DETAILED DESCRIPTION

[0016] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0017] The embodiments of the present invention include the following, and all the parts of the components are parts by weight. Example

[0018] 1) Add 25 parts of water to the reactor, then add 75 parts of succinic anhydride, heat to 80°C, and stir until dissolved; 2) Add 90 parts of glycine and 0.05 parts of transition metal catalyst to the reactor, then heat to 100 °C, stir for 60 minutes, cool to 45 °C, and add 50 parts of water to obtain a diluted stock solution; 3) Add 30 parts of water and 12 parts of N, N'-methylenebisacrylamide into the reactor, heat to 60°C, slowly drop the diluted stock solution and 30% sodium hydroxide solution, keep the pH of the system at 8-10, and add for 60 minutes. After completion, keep warm for 30 minutes, then cool to room temperature, and transport to a centrifugal spray drying tower for powder spraying and drying to finally obtain a polycarboxyl-modified protein gypsum retarder. Example

[0019] 1) Add 10 parts of water to the reactor, then add 90 parts of succinic anhydride, heat to 100 °C, and stir until dissolved; 2) Add 90 parts of glycine and 0.05 parts of transition metal catalyst to the reactor, then heat to 100 °C, stir for 60 minutes, cool to 50 °C, and add 50 parts of water to obtain a diluted stock solution; 3) Add 30 parts of water and 10 parts of N, N'-methylenebisacrylamide into the reactor, heat it to 60°C, slowly drop the diluted stock solution and 30% sodium hydroxide solution, keep the pH of the system at 8-10, and add for 60 minutes. After completion, keep warm for 30 minutes, then cool to room temperature, and transport it to a centrifugal spray drying tower for powder spray drying to obtain a polycarboxyl-modified protein gypsum retarder. Example

[0020] 1) Add 15 parts of water to the reactor, then add 85 parts of succinic anhydride, heat to 90°C, and stir until dissolved; 2) Add 102 parts of glycine and 0.05 parts of transition metal catalyst to the reactor, then heat to 110°C, stir for 60 minutes, cool to 60°C, and add 50 parts of water to obtain a diluted stock solution; 3) Add 30 parts of water and 12 parts of N, N'-methylenebisacrylamide into the reactor, heat to 60°C, slowly drop the diluted stock solution and 30% sodium hydroxide solution, keep the pH of the system at 8-10, and add for 60 minutes. After completion, keep warm for 30 minutes, then cool to room temperature, and transport to a centrifugal spray drying tower for powder spray drying to obtain a polycarboxyl-modified protein gypsum retarder. Example

[0021] 1) Add 25 parts of water to the reactor, then add 55 parts of succinic anhydride and 20 parts of tartaric acid, heat to 80°C, and stir until dissolved; 2) Add 90 parts of glycine and 0.05 parts of transition metal catalyst to the reactor, then heat to 110 °C, stir for 60 minutes, cool to 45 °C, and add 50 parts of water to obtain a diluted stock solution; 3) Add 30 parts of water and 12 parts of N, N'-methylenebisacrylamide into the reactor, heat to 60°C, slowly drop the diluted stock solution and 30% sodium hydroxide solution, keep the pH of the system at 8-10, and add for 60 minutes. After completion, keep warm for 30 minutes, then cool to room temperature, and transport to a centrifugal spray drying tower for powder spray drying to obtain a polycarboxyl-modified protein gypsum retarder. Example

[0022] 1) Add 25 parts of water to the reactor, then add 50 parts of succinic anhydride and 25 parts of tartaric acid, heat to 80°C, and stir until dissolved; 2) Add 75 parts of glutamic acid and 0.05 parts of transition metal catalyst to the reactor, then heat to 110 °C, stir for 60 minutes, cool to 45 °C, and add 50 parts of water to obtain a diluted stock solution; 3) Add 30 parts of water and 12 parts of N, N'-methylenebisacrylamide into the reactor, heat to 60°C, slowly drop the diluted stock solution and 30% sodium hydroxide solution, keep the pH of the system at 8-10, and add for 60 minutes. After completion, keep warm for 30 minutes, then cool to room temperature, and transport to a centrifugal spray drying tower for powder spray drying to obtain a polycarboxyl-modified protein gypsum retarder.

[0023] Comparative Example 1 Add 25 parts of water, 75 parts of succinic anhydride, 90 parts of glycine, 0.05 parts of transition metal catalyst and 12 parts of ethylene glycol diacrylate into the reactor, then heat to 100°C, stir for 60 minutes, add 80 parts of water, cool to 45°C to obtain a diluted stock solution, and then spray-dry the diluted stock solution to obtain a gypsum retarder.

[0024] Comparative Example 2 Tartaric acid was used alone as a gypsum retarder in the gypsum retarding experiment.

[0025] Comparative Example 3 The commercially available bone glue gypsum retarder was used as gypsum retarder in the gypsum retarding experiment.

[0026] In order to further evaluate the effect of the polycarboxyl modified protein gypsum retarder of the present invention on the setting time of gypsum, the gypsum retarder obtained in the above examples and comparative examples was used in the gypsum retarding experiment, and the retarder dosage was 0.08% of the mass of gypsum. The setting time of gypsum after adding the retarder was measured according to GB / T17669.4-1994 "Determination of physical properties of building gypsum paste" and GB / T 17669.3-1994 "Determination of physical properties of building gypsum paste". In addition, lime lime accounting for 2% of the total mass of gypsum was added to the gypsum, and the setting time of the above examples and comparative examples was tested under alkaline conditions. The measurement results are shown in Table 1.

[0027]

[0028] The experimental results show that the polycarboxyl modified protein gypsum retarder prepared under non-alkaline high pH and more suitable temperature reaction conditions has a better retarding effect under pure gypsum and alkaline conditions. Among them, the polycarboxylic acid and amino acid types used in Experimental Example 5 have a considerable improvement in the grafting retarding time.

[0029] Compared with Comparative Example 2, the present invention meets the requirements of gypsum construction by combining the retarder performance with macromolecular polycarboxylic acid groups and grafted protein amino acids, and avoids the problem that conventional organic acid small molecules have a short setting time and are unstable in gypsum.

[0030] Compared with Comparative Examples 1 and 3, the polycarboxyl-modified protein gypsum retarder prepared by the present invention has a stronger retarding effect. After being grafted with specific polycarboxylic acid organic matter and protein amino acid and active polyenyl amide, the retarding effect is better than that of the grafted product of ethylene glycol diacrylate, and is even better than the retarder obtained by hydrolysis of collagen.

[0031] The retarder production process of the present application not only avoids the environmental pollution problem caused by the high-temperature alkaline hydrolysis of the commonly used gelatin retarders on the market in terms of production environment, but also has the advantages of simple process, low energy consumption, low cost and no pollution. The gypsum retarder produced has the advantages of good solubility, high stability, no special odor, good retarding effect on gypsum, and small strength loss. At the same time, the present invention also provides a practical technical route for the reuse of food-grade protein resources.

[0032] A retarder for delaying the setting time of building gypsum and a preparation method thereof, The beneficial effects of the retarder for delaying the setting time of building gypsum and the preparation method of the present invention are: 1. Based on renewable food-grade protein raw materials and lower-cost poly-type grafted carboxylic acid derivatives, the molecular structure design has more active calcium ion chelating groups, thereby obtaining the key combination of active amide-polycarboxyl polyether, which has no odor, waste gas, or wastewater, and the process is simple and environmentally friendly; 2. Under the catalytic system, the yield of addition polymerization reaction can be improved. More effective amide bonds and polymer chains can better retain active carboxylic acid ions and molecular structures under strong acid or strong base conditions, such as in strong alkaline plaster gypsum in some special application scenarios, and improve the retarding effect of gypsum. At the same time, it is also easier to reduce the difference in retarding degree of the product in desulfurized and phosphorus building gypsum, thereby making the gypsum more adaptable and sensitive and having a wider range of applications.

[0033] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A method for preparing a retarder for delaying the setting time of building gypsum, characterized in that the steps include: (1) adding a small molecule polybasic carboxyl organic compound and water into a reaction kettle, heating to 60-80° C., stirring and dissolving to obtain a mixed solution; wherein the weight portion of the small molecule polybasic carboxyl organic compound is 75-90 parts, and the weight portion of water is 10-25 parts; the small molecule polybasic carboxyl compound is one or two of fumaric acid, citric acid, tartaric acid, succinic anhydride, and acetic anhydride; (2) adding 45-90 parts by weight of food-grade protein powder and 0.02-0.1 parts by weight of a transition metal catalyst to a mixed solution, then heating the solution to 70-110° C., stirring the solution to obtain a stock solution, then lowering the temperature of the stock solution to room temperature, and adding 35-55 parts by weight of water to obtain a diluted stock solution; wherein the food-grade protein powder comprises one or more of glycine, glutamic acid, lysine, aspartic acid, and aminobutyric acid; and the weight of the food-grade protein powder is 60-100% of the total weight of the small molecule polycarboxyl organic matter; (3) Add 30-50 parts by weight of water and 8-15 parts by weight of a cross-linking agent into the reactor, and heat it to 40-60°C. Then slowly add the diluted stock solution and pH adjuster into the reactor to keep the pH of the solution at a weak alkaline level. After completion, keep the temperature constant. (4) After the solution obtained in step (3) is cooled to room temperature, it is powdered and dried in a centrifugal spray tower to obtain a polycarboxyl-modified opal gypsum retarder.

2. A method for preparing a retarder for delaying the setting time of building gypsum according to claim 1, characterized in that: In step (1), the small molecule polycarboxyl compound comprises two components, one component is succinic anhydride, the weight proportion of which is 40 to 60 parts, and the other component is one of fumaric acid, citric acid, tartaric acid, and acetic anhydride, the total weight proportion of which is 40 to 60 parts.

3. A method for preparing a retarder for delaying the setting time of building gypsum according to claim 1, characterized in that: In step (2), the transition metal catalyst is one of Pt and Zn-based catalysts.

4. The method for preparing a retarder for delaying the setting time of building gypsum according to claim 1, characterized in that: In step (2), the reaction temperature of the mixture of food-grade protein powder and transition metal catalyst is 90-100°C, the stirring time is 30-90 minutes, and then the temperature is reduced to 30-50°C.

5. The method for preparing a retarder for delaying the setting time of building gypsum according to claim 1, characterized in that: The components of the food-grade protein powder and their weight proportions include 90-110 parts of glycine, 75-90 parts of lysine and 0-10 parts of other protein powders.

6. The method for preparing a retarder for delaying the setting time of building gypsum according to claim 1, characterized in that: In step (3), the cross-linking agent is one of glutaraldehyde, boric acid, sodium trimetaphosphate, N,N'-methylenebisacrylamide and ethylene glycol diacrylate, glutaminase, tannic acid and phytic acid.

7. The method for preparing a retarder for delaying the setting time of building gypsum according to claim 1, characterized in that: In step (3), the diluted stock solution and pH adjuster are added dropwise into the reaction kettle.

8. The method for preparing a retarder for delaying the setting time of building gypsum according to claim 1, characterized in that: In step (3), the pH adjuster is one of a sodium hydroxide solution and a calcium hydroxide solution.

9. The method for preparing a retarder for delaying the setting time of building gypsum according to claim 1, characterized in that: In step (3), the dropping time is 30-60 minutes, the solution pH value is 8-10, the insulation temperature is 40-60°C, and the insulation time is 30-60 minutes.

10. A retarder for delaying the setting time of building gypsum, characterized in that: Prepared by the preparation method described in any one of claims 1 to 7.

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