High-water-absorption base layer thin-batch plastering gypsum as well as preparation method and application thereof

Abstract

The invention relates to the technical field of plastering gypsum, in particular to high-water-absorption base-layer thin-batch plastering gypsum as well as a preparation method and application thereof. The high-water-absorption base-layer thin-batch plastering gypsum comprises the following components in parts by weight: 100-150 parts of calcium carbonate; 400 to 500 parts of semi-hydrated gypsum; 300 to 400 parts of calcium sand; 2.8 to 4.1 parts of composite cellulose; 6-10 parts of a thixotropic agent; 1-10 parts of an organic gelling agent; and 0.5 to 1.5 parts of a retarder. The formula is optimized, the whole water retention system is mainly redesigned, water is released step by step, a part of water is released too fast, a base layer is wetted firstly, the situation that the base layer scratches water into plastering gypsum is relieved, it is guaranteed that semi-hydrated gypsum in the plastering gypsum fully reacts with water, the strength is improved, and especially during thin-batch, the water retention effect is good. And sufficient hydration reaction is ensured, so that the phenomenon of thin-batch powder falling is avoided.

Description

Technical Field

[0001] This invention relates to the field of plastering technology, specifically to a high water absorption base thin-layer plastering, its preparation method, and its application. Background Technology

[0002] Plastering gypsum (compliant with standard GB / T 28627-2023) contains functional additives such as calcium carbonate, hemihydrate gypsum, cellulose, organic cementitious agents, thixotropic agents, and retarder. The main cementing substance is hemihydrate gypsum, with organic cementitious agents as auxiliary cementing substances. Cellulose primarily provides water retention and workability, allowing the product to be easily and smoothly applied to the wall with a trowel after adding water. Throughout the process, water is slowly released, providing moisture to the hemihydrate gypsum to gradually complete its hydration reaction into dihydrate gypsum. This completes the cementing process, ensuring that the final plastering gypsum meets the formula requirements for tensile strength, compressive strength, and flexural strength.

[0003] In the past, plaster products had a single water retention system and a relatively uniform rate of water release. This made it easy for plaster to fail to meet the requirements of the formula on some highly absorbent substrates due to insufficient hydration reaction. In particular, when applying a thin layer, the dry film was prone to powdering when touched. Summary of the Invention

[0004] The purpose of this invention is to provide a high water absorption base layer thin-layer plaster, its preparation method and application, to solve the technical problem in the prior art that plaster on a high water absorption base layer is prone to insufficient hydration reaction and fails to meet the formula requirements, especially when applied in thin layers, the dry film is prone to powdering when touched.

[0005] This invention discloses a high water absorption base layer thin-layer plaster, comprising the following components by weight: 100-150 parts of calcium carbonate; 400-500 parts of hemihydrate gypsum; 300-400 parts of calcium sand; 2.8-4.1 parts of complex cellulose; 6-10 parts of thixotropic agent; 1-10 parts organic gelling agent; 0.5-1.5 parts of retarder.

[0006] Furthermore, the thixotropic agent is modified bentonite or modified starch ether.

[0007] Furthermore, the organic gelling agent is gelling powder or instant polyvinyl alcohol.

[0008] Furthermore, the retarder is a protein-based or amino acid-based gypsum retarder.

[0009] Furthermore, the composite cellulose is a mixture of high-viscosity cellulose and low-viscosity cellulose.

[0010] Furthermore, the high-viscosity cellulose has a maximum viscosity greater than 40,000 and less than 200,000, while the low-viscosity cellulose has a viscosity of 40,000 and below.

[0011] Furthermore, the ratio of high-viscosity cellulose to low-viscosity cellulose is 25-35:3-6.

[0012] Furthermore, the composite cellulose is hydroxypropyl methylcellulose or methyl hydroxyethyl cellulose.

[0013] Furthermore, the calcium carbonate is heavy calcium carbonate.

[0014] Furthermore, the heavy calcium carbonate particles pass through an 80-120 mesh sieve.

[0015] Furthermore, the calcium sand has a particle size that passes through a 60-80 mesh sieve.

[0016] A method for preparing a thin-layer plaster base layer with high water absorption rate involves mixing the raw materials evenly, with the temperature range being 5-35 degrees Celsius during the mixing process.

[0017] Application of a thin-layer plastering compound with high water absorption rate for substrates with high water absorption rate.

[0018] Furthermore, the high water absorption base layer is gypsum board or precast calcium silicate board.

[0019] Furthermore, the water absorption rate of the high-absorption base layer is greater than 30% of its own weight.

[0020] Furthermore, when using it, mix the plaster and water in a mixer at a ratio of 1:0.38-0.4 and it is ready to use.

[0021] Furthermore, the mixed mortar should be used within 60 minutes. If the mortar hardens or becomes hot, do not add water or mix it again for reuse.

[0022] Furthermore, it can be used for leveling walls and ceilings in non-damp indoor areas.

[0023] Plastering gypsum reaction process: CaSO4 1 / 2H₂O + 3 / 2H₂O → CaSO₄ 2H2O (Calcium sulfate hemihydrate reacts with water to produce calcium sulfate dihydrate).

[0024] Compared with the prior art, the beneficial effects of the present invention are: 1. The present invention optimizes the formula, mainly by redesigning the entire water-retaining system, so that the water is released in stages. Some of the water that is released too quickly first wets the base layer, which slows down the situation where the base layer draws water from the plaster, ensuring that the hemihydrate plaster in the plaster can fully react with water, thereby improving the strength. Especially when applying thin coats, it ensures that the hydration reaction is sufficient, thereby avoiding the phenomenon of powdering when applying thin coats. 2. This invention allows gypsum to fully react with water, maximizing its strength. Attached Figure Description

[0025] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 This is the effect of thin batching in Embodiment 1 of the present invention.

[0027] Figure 2 This is the thin batch effect of Embodiment 2 of the present invention.

[0028] Figure 3 This is the thin-batch effect of Embodiment 3 of the present invention.

[0029] Figure 4 This is a comparative example 1 showing the effect of thin batch production in this invention.

[0030] Figure 5 This is a comparative example 2 showing the thin batch effect of the present invention.

[0031] Figure 6 This is a comparative example 3 showing the thin batch effect of the present invention.

[0032] Figure 7 This is a comparative example 4 showing the effect of thin batches in this invention. Detailed Implementation

[0033] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0034] Example 1 This embodiment discloses a high water absorption base layer thin-layer plaster, its preparation method, and its application, including the following steps: Mix 141g of 80-mesh heavy calcium carbonate, 450g of hemihydrate desulfurized gypsum, 400g of 60-mesh calcium sand, 2.5g of hydroxypropyl methylcellulose (HPMC) with a viscosity of 100,000, 0.6g of hydroxypropyl methylcellulose ether with a viscosity of 10,000, 10g of bentonite, 6g of adhesive powder, and 0.7g of amino acid-based gypsum retarder for 5 minutes to ensure uniform mixing at a temperature of 60 degrees Celsius.

[0035] When using, mix plaster and water in a mixer at a ratio of 1:0.39. Apply test pieces of different thicknesses (1cm, 0.5cm, 0.3cm, and 0.1cm) to a gypsum board with high water absorption. After curing for 7 days ± 2 hours at a temperature of 20±5 degrees Celsius and a humidity of 65±10%, touch the surface of the paint film to check the thickness. There should be no powdering when rubbed by hand.

[0036] Powder shedding test (experimental temperature: 37℃, humidity: 40%): A 0.3mm thick layer was applied to the test wall; after waiting 1 minute, another layer was applied. No peeling or powder shedding was observed. Figure 1 As shown.

[0037] Example 2 The only change from Example 1 is that 3g of hydroxypropyl methylcellulose with a viscosity of 100,000 and 0.4g of hydroxypropyl methylcellulose with a viscosity of 10,000 are used.

[0038] When using, mix plaster and water in a mixer at a ratio of 1:0.39. Apply test pieces of different thicknesses (1cm, 0.5cm, 0.3cm, and 0.1cm) to a gypsum board with high water absorption. After curing for 7 days ± 2 hours at a temperature of 20±5 degrees Celsius and a humidity of 65±10%, touch the surface of the paint film to check the thickness and rub it to see if there is any powdering.

[0039] Powder shedding test (experimental temperature: 37℃, humidity: 40%): A 0.3mm thick layer was applied to the test wall. After waiting 1 minute, no peeling occurred; after waiting 2 minutes, no peeling occurred; a thin layer applied and rubbed by hand showed no powder shedding. Figure 2 As shown.

[0040] Example 3 The only change from Example 1 is that the viscosity of hydroxypropyl methylcellulose is 3.5g at 100,000 and the viscosity of hydroxypropyl methylcellulose is 0.3g at 10,000.

[0041] When using, mix plaster and water in a mixer at a ratio of 1:0.39. Apply test pieces of different thicknesses (1cm, 0.5cm, 0.3cm, and 0.1cm) to a gypsum board with high water absorption. After curing for 7 days ± 2 hours at a temperature of 20±5 degrees Celsius and a humidity of 65±10%, touch the surface of the paint film to check the thickness and rub it to see if there is any powdering.

[0042] Powder shedding test (experimental temperature: 37℃, humidity: 40%): A 0.3mm thick layer was applied to the test wall; after waiting 1 minute, the layer peeled off; after waiting 2 minutes, the layer peeled off but no powder shedding occurred. Figure 3 As shown.

[0043] Comparative Example 1 The only change from Example 1 is that the viscosity of hydroxypropyl methylcellulose is 2.5g (100,000 viscosity) and the viscosity of hydroxypropyl methylcellulose is 0.2g (10,000 viscosity). When using, mix plaster and water in a mixer at a ratio of 1:0.39. Apply test pieces of different thicknesses (1cm, 0.5cm, 0.3cm, and 0.1cm) to a gypsum board with high water absorption. After curing for 7 days ± 2 hours at a temperature of 20±5 degrees Celsius and a humidity of 65±10%, touch the surface of the paint film to check the thickness. If powdering occurs when rubbing the film with your hand, it will be noticeable.

[0044] Powder shedding test (experimental temperature: 37℃, humidity: 40%): A 0.3mm thick layer was applied to the test wall. After waiting 1 minute, no peeling occurred; after waiting 2 minutes, slight peeling and powder shedding were observed. Figure 4 As shown.

[0045] Comparative Example 2 The only change from Example 1 is that the viscosity of hydroxypropyl methylcellulose is 3.5g at 100,000 and the viscosity of hydroxypropyl methylcellulose is 0.8g at 10,000.

[0046] When using, mix plaster and water in a mixer at a ratio of 1:0.40. Apply test pieces of different thicknesses (1cm, 0.5cm, 0.3cm, and 0.1cm) to a gypsum board with high water absorption. After curing for 7 days ± 2 hours at a temperature of 20±5 degrees Celsius and a humidity of 65±10%, check the thickness of the paint film by touching the surface. No powdering should occur when rubbing the surface. However, the workability is poor. When applying the plaster to the substrate with a trowel, more force is required, and the surface is not smooth, making it difficult to apply.

[0047] Powder shedding test (experimental temperature: 37℃, humidity: 40%): A 0.3mm thick layer was applied to the test wall; after waiting 1 minute, another layer was applied. There was no obvious peeling or powder shedding. Figure 5 As shown.

[0048] Comparative Example 3 The only change from Example 1 is that the viscosity of hydroxypropyl methylcellulose is 2.3g at 100,000 and the viscosity of hydroxypropyl methylcellulose is 0.5g at 10,000.

[0049] When using, mix plaster and water in a mixer at a ratio of 1:0.39. Apply test pieces of different thicknesses (1cm, 0.5cm, 0.3cm, and 0.1cm) to a gypsum board with high water absorption. After curing for 7 days ± 2 hours at a temperature of 20±5 degrees Celsius and a humidity of 65±10%, touch the surface of the paint film to check the thickness. Slight powdering may occur.

[0050] Powder shedding test (experimental temperature: 37℃, humidity: 40%): A 0.3mm thick layer was applied to the test wall; after waiting 1 minute, another layer was applied. Noticeable peeling and powder shedding were observed. Figure 6 As shown.

[0051] Comparative Example 4 The only change from Example 1 is that 4g of hydroxypropyl methylcellulose with a viscosity of 100,000 and 0.5g of hydroxypropyl methylcellulose with a viscosity of 10,000 are used.

[0052] When using, mix plaster and water in a mixer at a ratio of 1:0.40. Apply test pieces of different thicknesses (1cm, 0.5cm, 0.3cm, and 0.1cm) to a gypsum board with high water absorption. After curing for 7 days ± 2 hours at a temperature of 20±5 degrees Celsius and a humidity of 65±10%, touch the surface of the paint film to check the thickness. No powdering should occur. When applying with a trowel, due to the high viscosity of the paste, more force is required to apply it to the substrate, resulting in poor workability.

[0053] Powder shedding test (experimental temperature: 37℃, humidity: 40%): A 0.3mm thick layer was applied to the test wall; after waiting 1 minute, another layer was applied. No peeling or powder shedding was observed. Figure 7 As shown.

[0054] The above are the embodiments listed in this example. However, this example is not limited to the optional embodiments described above. Those skilled in the art can arbitrarily combine the above methods to obtain other various embodiments. Anyone can derive other various forms of embodiments based on the inspiration of this example. The above specific embodiments should not be construed as limiting the scope of protection of this example. The scope of protection of this example should be determined by the claims, and the specification can be used to interpret the claims.

Claims

1. A high water absorption base layer thin-layer plaster, characterized in that: It includes the following components in parts by weight: 100-150 parts of calcium carbonate; 400-500 parts of hemihydrate gypsum; 300-400 parts of calcium sand; 2.8-4.1 parts of complex cellulose; 6-10 parts of thixotropic agent; 1-10 parts organic gelling agent; 0.5-1.5 parts of retarder.

2. The high water absorption base thin-layer plastering gypsum according to claim 1, characterized in that: The thixotropic agent is modified bentonite or modified starch ether.

3. The high water absorption base thin-layer plastering gypsum according to claim 1, characterized in that: The organic gelling agent is gelling powder or fast-dissolving polyvinyl alcohol; And / or the calcium carbonate is heavy calcium carbonate; And / or the calcium sand particle size is such that it passes through a 60-80 mesh sieve; And / or the retarder is a protein-based or amino acid-based gypsum retarder.

4. The high water absorption base thin-layer plastering gypsum according to claim 1, characterized in that: The composite cellulose is a mixture of high-viscosity cellulose and low-viscosity cellulose.

5. The high water absorption base thin-layer plastering gypsum according to claim 4, characterized in that: The high-viscosity cellulose has a maximum viscosity of greater than 40,000 and less than 200,000, while the low-viscosity cellulose has a viscosity of 40,000 and less.

6. The method for preparing a high water absorption base layer thin-layer plastering gypsum according to claim 4, characterized in that: The ratio of high-viscosity cellulose to low-viscosity cellulose is 25-35:3-6.

7. The method for preparing a high water absorption base layer thin-layer plastering gypsum according to claim 1, characterized in that: The composite cellulose is hydroxypropyl methylcellulose or methyl hydroxyethyl cellulose.

8. A method for preparing a thin-layer plaster base layer with high water absorption, characterized in that: The raw materials are mixed evenly, and the temperature range during the mixing process is 5-35 degrees Celsius. The raw materials are components of a high water absorption base thin-layer plastering gypsum as described in any one of claims 1-7.

9. The application of the high water absorption base thin-layer plastering gypsum according to any one of claims 1-7 or the plastering gypsum prepared according to claim 8, characterized in that: Used for base layers with high water absorption.

10. The application according to claim 9, characterized in that: The high water absorption rate of the base layer is greater than 30% of its own weight.

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