A cement board, its production process, and its application in formwork-free systems.
By modifying the fibers with acyl chloride compounds, the water absorption rate of the cement board is reduced, its mechanical properties in humid environments are improved, the problem of poor water resistance of fiber cement boards is solved, and the application range is broadened.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- TANGSHAN WANJU BUILDING MATERIALS CO LTD
- Filing Date
- 2024-03-02
- Publication Date
- 2026-05-26
AI Technical Summary
Existing fiber cement boards have high fiber water absorption and poor water resistance, which leads to a decline in mechanical properties in humid environments and limits their application range.
Acyl chloride compounds are used to modify fibers. By mixing and modifying the fibers, hydrophobic groups are imparted to the fibers, which reduces the water absorption rate of cement boards and improves their water resistance.
It reduces the water absorption rate of cement boards, improves their mechanical properties in humid environments, meets the JC/T412.1-2018 standard, and broadens their application range.
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Abstract
Description
Technical Field
[0001] This invention relates to the field of building materials technology, specifically to a cement board, its production process, and its application in formwork that does not require dismantling. Background Technology
[0002] Cement board is a building slab made primarily from cement. It is a building product that can be freely cut, drilled, and carved. It is mainly divided into three categories: ordinary cement board, fiber cement board, and fiber cement pressure board. Among them, fiber cement board is widely used in various fields such as building exterior walls, interior wall decoration, partitions, ceilings, and floors due to its excellent properties such as lightweight, high strength, fire resistance, moisture resistance, and durability.
[0003] Fiber cement board, also known as fiber reinforced cement board, is a cement-based composite material made of cement mortar or neat cement paste as the base material and discontinuous short fibers or continuous long fibers as reinforcing materials. Existing fiber cement boards have high fiber water absorption and poor water resistance, which causes a significant decrease in the mechanical properties of the fiber cement board in humid environments, thus greatly limiting its applications. Summary of the Invention
[0004] This invention proposes a cement board, its production process, and its application in non-removable formwork, which solves the problems of high fiber water absorption and poor water resistance in fiber cement boards in related technologies.
[0005] The technical solution of the present invention is as follows:
[0006] A cement board comprising the following components in parts by weight: 60-80 parts cement, 20-30 parts slag, 30-40 parts quartz sand, 0.5-1.5 parts water-reducing agent, 1-3 parts thickener, 10-30 parts acyl chloride compound modified fiber, 1-3 parts desulfurized gypsum, and 20-30 parts water.
[0007] As a further technical solution, the raw materials for the acyl chloride compound modified fiber include fiber and acyl chloride compound in a mass-to-volume ratio of 3g:40~60mL.
[0008] As a further technical solution, the acyl chloride compound includes one or both of 3,5-dimethylbenzoyl chloride and acetoxyacetyl chloride.
[0009] As a further technical solution, the acyl chloride compound includes 3,5-dimethylbenzoyl chloride and acetoxyacetyl chloride in a mass ratio of 3:2 to 9:1.
[0010] As a further technical solution, the fiber includes one or both of glass fiber and carbon fiber.
[0011] As a further technical solution, the preparation method of the acyl chloride compound modified fiber includes the following steps: mixing the acyl chloride compound with the fiber and modifying it at 40~50℃ for 1~3h to obtain the acyl chloride compound modified fiber.
[0012] As a further technical solution, after modification, the product is washed with toluene and dried.
[0013] As a further technical solution, the water-reducing agent includes one or two of polycarboxylate-based water-reducing agents and naphthalene-based water-reducing agents.
[0014] As a further technical solution, the thickener includes one or both of hydroxypropyl methylcellulose and redispersible latex powder.
[0015] The present invention also proposes a production process for cement board, comprising the following steps: mixing the components in the specified mass fractions evenly, molding, curing, and obtaining cement board.
[0016] The present invention also proposes the application of the described cement board or the cement board obtained by the described production process in non-removable formwork.
[0017] The working principle and beneficial effects of this invention are as follows:
[0018] 1. This invention reduces the water absorption rate of cement boards and improves their water resistance by modifying fibers with acyl chloride compounds, thereby enhancing the mechanical properties of fiber cement boards in humid environments. The reason for this is that acyl chloride compounds can impart hydrophobic groups, including ester, alkyl, and phenyl groups, to the fiber surface, fundamentally reducing the hydrophobicity of the fibers. This solves the problems of high water absorption and poor water resistance in existing fiber cement boards, achieving the effect of reducing water absorption and improving the mechanical strength of cement boards in humid environments.
[0019] 2. This invention uses 3,5-dimethylbenzoyl chloride and acetoxyacetyl chloride in a mass ratio of 3:2 to 9:1 as acyl chloride compounds to modify fibers, further reducing the water absorption rate of cement boards and further improving the mechanical strength of cement boards in humid environments. The reason is that 3,5-dimethylbenzoyl chloride contains a rigid benzene ring, which can provide relatively high mechanical strength, but also has significant steric hindrance. Adding some acetoxyacetyl chloride can achieve a better modification effect. Detailed Implementation
[0020] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.
[0021] The types of raw materials used in the following examples and comparative examples are as follows:
[0022] The cement is PO 42.5 ordinary Portland cement;
[0023] The slag is S95 grade slag powder with a mesh size of 200 mesh;
[0024] The quartz sand has a mesh size of 60, a silica content of 99.5 wt%, and a density of 3.0 g / cm³. 3 ;
[0025] The naphthalene-based water-reducing agent is Point-N200, a high-efficiency naphthalene-based water-reducing agent.
[0026] The polycarboxylate-based water-reducing agent is polycarboxylate-based water-reducing agent 530P;
[0027] Both glass fiber and carbon fiber are 6mm in length.
[0028] Example 1
[0029] (1) Preparation of acyl chloride modified fiber: 30g of glass fiber was added to 500mL of 3,5-dimethylbenzoyl chloride and modified at 45℃ for 2h. After the modification was completed, the fiber was washed twice with toluene and dried to obtain acyl chloride modified fiber.
[0030] (2) Mix 70 parts of cement, 25 parts of slag, 35 parts of quartz sand, 20 parts of acyl chloride modified fiber and 1 part of polycarboxylate water-reducing agent evenly, add 2 parts of redispersible latex powder and 2 parts of desulfurized gypsum and continue mixing, finally add 25 parts of water and mix evenly, pour into a mold and press into shape, cure at 20℃ for 24 hours, then cure at 150℃ and 1MPa for 10 hours to obtain cement board.
[0031] Example 2
[0032] (1) Preparation of acyl chloride modified fiber: 30g of glass fiber was added to 400mL of 3,5-dimethylbenzoyl chloride and modified at 40℃ for 3h. After the modification was completed, the fiber was washed twice with toluene and dried to obtain acyl chloride modified fiber.
[0033] (2) Mix 60 parts of cement, 20 parts of slag, 30 parts of quartz sand, 10 parts of acyl chloride modified fiber, and 0.5 parts of naphthalene-based water-reducing agent evenly. Then add 1 part of hydroxypropyl methylcellulose and 1 part of desulfurized gypsum and continue mixing. Finally, add 20 parts of water and mix evenly. Pour into a mold and press into shape. After curing at 20℃ for 24 hours, cure at 150℃ and 1MPa for 10 hours to obtain cement board.
[0034] Example 3
[0035] (1) Preparation of acyl chloride modified fiber: 30g of glass fiber was added to 600mL of 3,5-dimethylbenzoyl chloride and modified at 50℃ for 1h. After the modification was completed, the fiber was washed with toluene 3 times and dried to obtain acyl chloride modified fiber.
[0036] (2) Mix 80 parts of cement, 30 parts of slag, 40 parts of quartz sand, 30 parts of acyl chloride modified fiber and 1.5 parts of naphthalene water-reducing agent evenly, add 3 parts of redispersible latex powder and 3 parts of desulfurized gypsum and continue mixing, finally add 30 parts of water and mix evenly, pour into a mold and press into shape, cure at 20℃ for 24 hours, then cure at 150℃ and 1MPa for 10 hours to obtain cement board.
[0037] Example 4
[0038] (1) Preparation of acyl chloride modified fiber: 30g of glass fiber was added to 500mL of acetoxyacetyl chloride and modified at 45℃ for 2h. After the modification was completed, the fiber was washed twice with toluene and dried to obtain acyl chloride modified fiber.
[0039] (2) Mix 70 parts of cement, 25 parts of slag, 35 parts of quartz sand, 20 parts of acyl chloride modified fiber and 1 part of polycarboxylate water-reducing agent evenly, add 2 parts of redispersible latex powder and 2 parts of desulfurized gypsum and continue mixing, finally add 25 parts of water and mix evenly, pour into a mold and press into shape, cure at 20℃ for 24 hours, then cure at 150℃ and 1MPa for 10 hours to obtain cement board.
[0040] Example 5
[0041] (1) Preparation of acyl chloride modified fiber: 30g of glass fiber was added to 500mL of a mixture of 3,5-dimethylbenzoyl chloride and acetoxyacetyl chloride with a volume ratio of 9:1. The mixture was modified at 45℃ for 2h. After the modification was completed, the fiber was washed twice with toluene and dried to obtain acyl chloride modified fiber.
[0042] (2) Mix 70 parts of cement, 25 parts of slag, 35 parts of quartz sand, 20 parts of acyl chloride modified fiber and 1 part of polycarboxylate water-reducing agent evenly, add 2 parts of redispersible latex powder and 2 parts of desulfurized gypsum and continue mixing, finally add 25 parts of water and mix evenly, pour into a mold and press into shape, cure at 20℃ for 24 hours, then cure at 150℃ and 1MPa for 10 hours to obtain cement board.
[0043] Example 6
[0044] (1) Preparation of acyl chloride modified fiber: 30g of glass fiber was added to 500mL of a mixture of 3,5-dimethylbenzoyl chloride and acetoxyacetyl chloride with a volume ratio of 4:1. The mixture was modified at 45℃ for 2h. After the modification was completed, the fiber was washed twice with toluene and dried to obtain acyl chloride modified fiber.
[0045] (2) Mix 70 parts of cement, 25 parts of slag, 35 parts of quartz sand, 20 parts of acyl chloride modified fiber and 1 part of polycarboxylate water-reducing agent evenly, add 2 parts of redispersible latex powder and 2 parts of desulfurized gypsum and continue mixing, finally add 25 parts of water and mix evenly, pour into a mold and press into shape, cure at 20℃ for 24 hours, then cure at 150℃ and 1MPa for 10 hours to obtain cement board.
[0046] Example 7
[0047] (1) Preparation of acyl chloride modified fiber: 30g of glass fiber was added to 500mL of a mixture of 3,5-dimethylbenzoyl chloride and acetoxyacetyl chloride in a volume ratio of 3:2. The mixture was modified at 45℃ for 2h. After the modification was completed, the fiber was washed twice with toluene and dried to obtain acyl chloride modified fiber.
[0048] (2) Mix 70 parts of cement, 25 parts of slag, 35 parts of quartz sand, 20 parts of acyl chloride modified fiber and 1 part of polycarboxylate water-reducing agent evenly, add 2 parts of redispersible latex powder and 2 parts of desulfurized gypsum and continue mixing, finally add 25 parts of water and mix evenly, pour into a mold and press into shape, cure at 20℃ for 24 hours, then cure at 150℃ and 1MPa for 10 hours to obtain cement board.
[0049] Comparative Example 1
[0050] Mix 70 parts cement, 25 parts slag, 35 parts quartz sand, 20 parts acyl chloride modified fiber, and 1 part polycarboxylate water-reducing agent evenly. Then add 2 parts redispersible latex powder and 2 parts desulfurized gypsum and continue mixing. Finally, add 25 parts water and mix evenly. Pour the mixture into a mold and press it into shape. After curing at 20℃ for 24 hours, cure at 150℃ and 1MPa for 10 hours to obtain cement board.
[0051] The cement boards obtained in Examples 1-7 and Comparative Example 1 were tested for water absorption according to the method in GB / T 7019-2014 "Test Methods for Fiber Cement Products". The flexural strength was tested after 48 hours of water saturation according to the method in GB / T 7019-2014 "Test Methods for Fiber Cement Products". The test results are recorded in Table 1.
[0052] Table 1 Water absorption and flexural strength
[0053]
[0054] As can be seen from Table 1, the water absorption rate of the cement board provided by the present invention is below 14.6%, and the flexural strength after 48 hours of saturation is above 22.5 MPa. It has low water absorption and high saturated strength, can be used in humid environments, meets the standard in JC / T412.1-2018, and broadens the application range of cement board.
[0055] Compared with Comparative Example 1, Examples 1-7 used acyl chloride compound modified fibers, while Comparative Example 1 did not modify the fibers. The water absorption rate of the cement boards obtained in Examples 1-7 was lower than that in Comparative Example 1, and the flexural strength after 48 hours of saturation was higher than that in Comparative Example 1. This shows that using acyl chloride compound modified fibers can reduce the water absorption rate of cement boards and improve water resistance, thereby improving the mechanical properties of fiber cement boards in humid environments.
[0056] Compared with Examples 5-7, Examples 1 and 4 use 3,5-dimethylbenzoyl chloride modified fibers, Examples 4 use acetoxyacetyl chloride modified fibers, and Examples 5-7 use both 3,5-dimethylbenzoyl chloride and acetoxyacetyl chloride modified fibers. The water absorption rate of the cement boards obtained in Examples 1 and 4 is higher than that in Examples 5-7, and the flexural strength after 48 hours of saturation is lower than that in Examples 5-7. This indicates that using 3,5-dimethylbenzoyl chloride and acetoxyacetyl chloride as acyl chloride compounds to modify the fibers can further reduce the water absorption rate of the cement boards and further improve the mechanical strength of the cement boards in humid environments.
[0057] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.
Claims
1. A cementitious panel, characterized by, The composition comprises the following components in parts by weight: 60-80 parts cement, 20-30 parts slag, 30-40 parts quartz sand, 0.5-1.5 parts water-reducing agent, 1-3 parts thickener, 10-30 parts acyl chloride modified fiber, 1-3 parts desulfurized gypsum, and 20-30 parts water. The acyl chloride modified fiber raw material contains 3,5-dimethylbenzoyl chloride and acetoxyacetyl chloride in a mass ratio of 3:2 to 9:
1.
2. A cementitious panel according to claim 1, wherein, The raw materials for the acyl chloride-modified fiber include fiber and acyl chloride compound in a mass-to-volume ratio of 3g:40~60mL.
3. A cement board according to claim 2, characterized in that, The fiber includes one or both of glass fiber and carbon fiber.
4. A cement board according to claim 1, characterized in that, The preparation method of the acyl chloride compound modified fiber includes the following steps: mixing the acyl chloride compound with the fiber and modifying it at 40~50℃ for 1~3h to obtain the acyl chloride compound modified fiber.
5. A cement board according to claim 4, characterized in that, After modification, the product was washed with toluene and dried.
6. A cement board according to claim 1, characterized in that, The water-reducing agent includes one or two of polycarboxylate-based water-reducing agents and naphthalene-based water-reducing agents; The thickener includes one or both of hydroxypropyl methylcellulose and redispersible latex powder.
7. A cement board production process according to any one of claims 1 to 6, characterized in that, Includes the following steps: The components of the specified mass fraction are mixed evenly, molded, and cured to obtain a cement board.
8. The application of the cement board as described in any one of claims 1 to 6 or the cement board obtained by the production process described in claim 7 in the formwork that does not require dismantling.