TWI537228B - Gypsum composition, a gypsum product and their preparation method - Google Patents

Description

Gypsum composition and gypsum product and preparation method thereof

The present invention relates to a gypsum composition and a gypsum product, in particular to a gypsum composition, a gypsum board and a process for its preparation, and the use of dehydroascorbic acid as an anti-deformation additive in gypsum products.

In the field of modern construction, gypsum (the main component calcium sulphate dihydrate) is the main material used in the construction industry, including gypsum board used to form ceilings and walls in buildings, and mortar used in the processing of suspended ceilings/walls.

In the process of preparing the gypsum product, a mixture of calcined gypsum (calcium sulfate hemihydrate and/or anhydrous calcium sulfate) and water is cast, wherein the calcined gypsum (mortar) is hydrated to form a set gypsum comprising a crystallized hydrated gypsum matrix (calcium sulfate dihydrate), which makes gypsum products have high structural strength; gypsum products are widely used in construction products because of their light weight and high strength.

However, if the gypsum product is exposed to high humidity for a long period of time, it will be easily deformed, which is called drooping or wet deformation in the industry. The deformed gypsum product may cause structural stability doubt and affect vision after installation. On the look and feel, and need expensive repair work to repair, so how to overcome the problem of poor resistance to deformation of the set gypsum is built The focus of research in the construction industry.

For example, Chinese Patent Application Publication No. CN101747014A discloses a method for improving the sag resistance of a gypsum product by adding boric acid to the calcined gypsum as an additive. British Patent GB 1 481 788 A discloses the use of Gallic acid as an anti-sagging additive to increase the sag resistance of gypsum board. British Patent GB 1226333 A discloses precast gypsum mortar sheets, sheets and blocks containing tartaric acid having greater resistance to plasticity than similar products without tartaric acid. It is also known to use phosphates as disclosed in U.S. Patent No. 6,342,284.

definition

"Gypsum product" as used in this specification and the scope of its patent application refers to articles of various possible forms, such as gypsum board, which are composed of gypsum.

The term "anti-deformation ability" as used in this specification and the scope of the patent application, unless otherwise specified, generally refers to the ability to resist sagging, but does not exclude the possibility of deformation against other possible forms.

The singular forms "a", "an" and "the"

this invention

In view of the poor resistance to deformation of existing gypsum products and the sag and creep under humidity conditions, resulting in poor stability, the present invention provides a gypsum composition and a method for preparing gypsum board and gypsum board, the gypsum composition Including an anti-deformation additive made of the gypsum composition The gypsum board has good resistance to deformation under humidity and high temperature conditions, especially sag resistance, thereby improving the stability of the gypsum product.

The present invention provides a gypsum composition, a gypsum board and a preparation method thereof, and dehydroascorbic acid (DHA) as an anti-deformation additive in gypsum products.

The gypsum composition comprising a gypsum and an anti-deformation additive; the gypsum is hemihydrate gypsum (calcium sulfate hemihydrate); the anti-deformation additive comprises a dehydroascorbate selected from the group consisting of dehydroascorbic acid, dehydroascorbate, and semi-decoloration. Hydrogen ascorbic acid (MDHA, also known as monodehydroascorbic acid, which has the same composition as hemihydroascorbic acid) or a combination thereof. .

The present invention also provides a method of forming a gypsum composition, comprising: mixing a gypsum powder and an anti-deformation additive with water to obtain a mixture, wherein the anti-deformation additive comprises a dehydrogenated ascorbic acid, Hydrogen ascorbate, semi-dehydroascorbic acid or a combination thereof.

Preferably, the gypsum composition further comprises one or more ingredients selected from the group consisting of starch, foaming agents, coagulants, dispersants, and other materials known to those skilled in the art of gypsum board and mortar manufacturing. Auxiliary additive.

The present invention also provides a gypsum board comprising: a gypsum, a starch, a dispersant, a coagulant, an anti-deformation additive, an optionally added blowing agent, and a technician in the field of gypsum board and mortar manufacturing. A known material, wherein the gypsum is dihydrate gypsum (calcium sulfate dihydrate); the anti-deformation additive comprises a dehydrogenated ascorbic acid, dehydroascorbate, semi-dehydroascorbic acid or a combination thereof.

The present invention also provides a method for forming a gypsum board, comprising the steps of: mixing a gypsum, a starch, a coagulant, a dispersant, an anti-deformation additive, and an optionally added foaming agent with water; A mixture is obtained, wherein the anti-deformation additive comprises a mixture selected from the group consisting of dehydroascorbic acid, dehydroascorbate, semi-dehydroascorbic acid or a combination thereof; the mixture is stirred to form a slurry; and the slurry is formed between the two liners. A sandwich structure, based on the sandwich structure, forming a first plate, the first plate being subjected to a hardening process and cut into a plurality of second plates having a desired length, and the second plates are dried to evaporate excess water to obtain the gypsum board.

In particular, the slurry is typically deposited on a liner (eg, paper or a nonwoven mat comprising polymer and/or glass fibers, etc.) and covered with another liner such that the slurry is sandwiched between the liners Forming the sandwich structure with the pad and the other pad, forming a first plate through a pair of forming plates or rollers for determining the thickness of the prepared gypsum board, and then forming the sandwich structure along Conveying line conveying, a hardened structure of the first plate after hydration and hardening for a period of time, cutting the hardened structure into the second plates of desired length, and transferring them to a drying system to evaporate excess water The gypsum board is obtained.

Preferably, the anti-deformation additive is dehydroascorbic acid.

Preferably, in the gypsum composition and the gypsum product, the mass percentage of the anti-deformation additive relative to the gypsum is 0.01 to 5.0%; more preferably, the minimum mass percentage of the anti-deformation additive relative to the gypsum is preferred. The value was 0.1%, and the maximum value of the mass percentage of the anti-deformation additive relative to the gypsum was 1.0%.

This creation also provides dehydroascorbic acid as an anti-deformation A method of application of an additive in a gypsum product.

The gypsum composition and the gypsum product and the method of producing the same have the following advantages compared to the prior art, in the present creation, the gypsum board comprises set gypsum made of the gypsum composition; and the gypsum composition comprises the semi-water Gypsum and the anti-deformation additive, wherein the anti-deformation additive comprises a selected from the group consisting of dehydroascorbic acid, dehydroascorbate, semi-dehydroascorbic acid or a combination thereof; the set gypsum made from the gypsum composition is compared to the prior art The better anti-deformation ability can effectively improve the anti-deformation ability of gypsum products. Even under high humidity conditions, the gypsum products of the present invention have strong stability and are difficult to be deformed, so as to meet the requirements for high stability.

As described in the background art, gypsum has the advantages of light weight and high structural strength, and is widely used in the construction industry. However, in actual use, it is found that gypsum products containing gypsum as a main component may sag or creep when exposed to high humidity, that is, the existing gypsum products have poor resistance to deformation under high humidity conditions, and the gypsum products are affected. Beautiful, resulting in failure to meet the standards of the construction industry.

In order to solve the defects of poor resistance to deformation and poor stability of the existing gypsum products, the present invention provides a gypsum composition and a gypsum product made from the gypsum composition and a preparation method thereof; compared with the prior art, The resistance to deformation (specifically, the ability to resist sag) of gypsum products made from the gypsum composition of the present invention is significantly improved.

The gypsum composition of the present invention comprises: a gypsum, an anti-deformation additive and water; the gypsum is hemihydrate gypsum (the main component is calcium sulfate hemihydrate), and the anti-deformation additive comprises a dehydroascorbic acid selected from the group. Hydrogen ascorbate, semi-dehydroascorbic acid or a combination thereof.

Specifically, the anti-deformation additive is dehydroascorbic acid, and the chemical formula of dehydroascorbic acid (C ₆ H ₆ O ₆ ) is as follows:

In the gypsum composition, the quality ratio of the anti-deformation additive to the hemihydrate gypsum is 0.01% to 5.0%, preferably 0.1% to 1.0%.

The gypsum composition further includes an additive selected from the group consisting of a blowing agent, a dispersing agent, a coagulant, starch, or a combination thereof to improve the quality of the gypsum board made from the gypsum composition.

The method for preparing the gypsum composition comprises: mixing a gypsum powder and an anti-deformation additive in water in a specific ratio to obtain a mixture; and stirring the mixture to obtain the gypsum composition; wherein the anti-deformation additive is selected from the group consisting of In the preparation of the gypsum composition of the present invention, the dehydrogenated ascorbic acid, dehydroascorbate, dehydroascorbate or a combination thereof is suitable for industrial large-scale promotion.

The present invention further provides a gypsum product made of the foregoing gypsum composition, which is a gypsum board, the gypsum board comprising: a gypsum, a starch, a dispersant, a coagulant, an anti-deformation additive and a selectively added blowing agent, the anti-deformation additive being selected from the group consisting of dehydroascorbic acid, dehydroascorbate, semi-dehydroascorbic acid or In combination, the gypsum is dihydrate gypsum.

Further, the periphery of the gypsum board may be covered with a liner which is a paper or a non-woven mat containing polymer and/or glass fiber or the like to form a gypsum product having a specific shape and use.

The present invention further provides a method for preparing the gypsum board, which comprises: a gypsum, a starch, a foaming agent, a coagulant, a dispersant, an anti-deformation additive, and a technician known in the art of gypsum board and mortar manufacturing. The material is mixed in water to obtain a mixture, and the mixture is stirred to form a slurry, wherein the anti-deformation additive is selected from the group consisting of dehydroascorbic acid, dehydroascorbate, semi-dehydroascorbic acid or a combination thereof; and then the slurry Deposited on a liner (such as paper or a nonwoven mat comprising polymer and/or fiberglass, etc.) and covered with another liner such that the slurry is sandwiched between the liner and the other liner Forming a sandwich structure, forming a first plate through a pair of forming plates or rolls for determining the thickness of the prepared gypsum board; and then conveying the first plate along a conveying line, the first plate After hydration and hardening for a period of time, the structure can be hardened, the hardened structure is cut into a plurality of second plates having a desired length, and the second plates are transferred to a drying system to evaporate excess water. Gypsum board.

In order to make the purpose, features and advantages of the present invention more comprehensible, the gypsum composition of the present invention and the gypsum product made of the gypsum composition and the preparation method thereof are further illustrated by the embodiments of the present invention; Gypsum products made from the gypsum composition of the present invention are excellent in sagging resistance ability.

In the following description, more specific details are set forth in order to facilitate a full understanding of the present invention, but the present invention may be practiced otherwise than as described herein. Therefore, the present creation is not limited by the following embodiments.

Example

I. The preparation process of the examples and the control samples is as follows:

The anti-deformation additive powder (the composition of the anti-deformation additive and the content of the comparative example shown in Table 1) and 500 g of the calcined calcium sulfate hemihydrate powder were mixed with 350 g of water to obtain a mixture, and the mixture was stirred for 15 seconds to obtain a slurry. .

The slurry was poured into a mold, and a gypsum board having a size of 400×400×10 mm was prepared after 12 hours, and the formed gypsum board was taken out and dried at 50 to 70° C. for 10 to 15 hours, and then at 30. Dry at ~50 °C for 20~30 hours. Finally, the gypsum board is placed at a temperature of 20 ° C and a relative humidity of 50% RH for 24 hours, and then cut into a sample of gypsum board having a size of 320 × 40 × 10 mm. For anti-sagging test.

II. Anti-sagging test process:

Test environment: constant temperature 20 ± 0.5 ° C; relative humidity: 93 ± 3% RH.

The gypsum board sample was horizontally placed on two supports, the distance between the two supports was 300 mm, and a metal load bearing block was placed in the center portion of the gypsum board sample (the mass of the metal bearing block is shown in Table 1) To speed up the drooping process; during the 24-hour period, the laser displacement meter (Model: Keyence IL-065) was used to continuously test the sag of the center portion of the gypsum board sample, and the sag after 24 hours of each gypsum board sample was recorded after 24 hours. the amount.

The composition of the anti-deformation additive in the examples and the comparative examples and the sag after 24 hours of the gypsum board samples corresponding to the examples and the comparative examples are shown in Table 1; wherein the anti-deformation additive content is the respective examples or the respective examples. The mass of the medium deformation resistant additive powder is divided by the mass of the calcium sulfate hemihydrate powder.

III. Analysis of test results:

From the 24 hour sag amount (as shown in Table 1), it was found that the introduction of 0.1% dehydroascorbic acid significantly enhanced the sag resistance of the gypsum sample.

Further, a gypsum board sample containing dehydroascorbic acid as an anti-deformation additive has better sag resistance, and contains dehydroascorbate and semi-dehydroascorbic acid similar in structure to dehydroascorbic acid as an anti-deformation additive. Gypsum board samples also showed better sag resistance.

Relative to the control, containing an anti-deformation comprising a mixture selected from the group consisting of dehydroascorbic acid, dehydroascorbate, semi-dehydroascorbic acid or a combination thereof The gypsum board sample of the additive has a significantly better sag resistance; further, the mass ratio of the anti-deformation additive to gypsum is 0.01 to 5.0%; further, the mass ratio of the anti-deformation additive to gypsum is preferred It is 0.1~1.0%.

The invention also provides the use of dehydroascorbic acid as an anti-deformation additive in a gypsum product, and any form of anti-deformation additive comprising dehydroascorbic acid and the anti-deformation additive are used in the protection of the gypsum product drooping behavior. Within the scope.

The above description is only a preferred example of the present invention, and is not intended to limit the present invention in any way. Although the present invention has been disclosed above in the preferred embodiment, it is not intended to limit the present invention, and is generally in the art. Those skilled in the art, while departing from the technical scope of the present invention, may make some modifications or modifications to equivalent embodiments by using the technical contents disclosed above, but the content of the technical solution without departing from the present invention is based on The technical essence of the present invention makes any simple modification, equivalent change and modification to the above embodiments, and still belongs to the scope of the technical solution of the present invention.

Claims (10)

A gypsum composition comprising: a gypsum and an anti-deformation additive comprising dehydroascorbic acid (DHA), dehydroascorbate, and dehydroascorbic acid (monodehydroascordic acid, MDHA) or a combination thereof. The gypsum composition according to claim 1, wherein the anti-deformation additive is dehydroascorbic acid. The gypsum composition according to any one of claims 1 to 2, wherein the mass ratio of the anti-deformation additive to the gypsum is from 0.01% to 5%. A method of forming a gypsum composition, comprising: mixing a gypsum powder and an anti-deformation additive with water to obtain a mixture; and agitating the mixture, wherein the anti-deformation additive is selected from the group consisting of dehydroascorbic acid, dehydroascorbate , semi-dehydroascorbic acid or a combination thereof. The method of forming a gypsum composition according to claim 4, wherein the mass ratio of the anti-deformation additive to the gypsum powder is 0.01 to 5.0%. A gypsum board comprising: a gypsum, a starch, a dispersant, a coagulant, an anti-deformation additive and a selectively added blowing agent, wherein the anti-deformation additive is selected from the group consisting of dehydroascorbic acid and Hydrogen ascorbate, semi-dehydroascorbic acid or a combination thereof. The gypsum board according to claim 6, wherein the anti-deformation additive is dehydroascorbic acid. The gypsum board according to any one of claims 6 to 7, wherein the mass ratio of the anti-deformation additive to the gypsum is from 0.01% to 5.0%. A method for forming a gypsum board, comprising: mixing a gypsum, a starch, a coagulant, a dispersing agent, an anti-deformation additive, and a selectively added blowing agent with water to obtain a mixture, wherein the anti-corrosion The deformation additive is selected from the group consisting of dehydroascorbic acid, dehydroascorbate and semi-dehydroascorbic acid or a combination thereof; the mixture is stirred to form a slurry; the slurry is placed between the two liners to form a sandwich structure; Forming a first plate based on the sandwich structure; the first plate is subjected to a hardening process and cut into a plurality of second plates having a desired length; and the second plates are dried to evaporate excess water to obtain the gypsum board. The method of forming a gypsum board according to claim 9, wherein the mass ratio of the anti-deformation additive to the gypsum is 0.01% to 5.0%.