High-acid-resistance calcium carbonate modified wall protection plate and preparation method thereof

Abstract

The invention provides a high-acid-resistance calcium carbonate modified wall panel and a preparation method thereof. The high-acid-resistance calcium carbonate modified wall panel is prepared from matrix resin, composite modified calcium carbonate, reinforced fibers, a weather-resistant auxiliary agent and a processing auxiliary agent. According to the invention, the calcium carbonate which is coated by SiO2, then is subjected to coupling treatment by a silane coupling agent and then is grafted with a fluorine-containing acrylate chain segment is added into the calcium carbonate modified wainscot, and the calcium carbonate is subjected to'inorganic coating-organic grafting 'dual modification, so that the acid resistance of the calcium carbonate and the dispersion stability of the calcium carbonate in a matrix are remarkably improved; the finally obtained calcium carbonate modified wall protection plate has better acid resistance, the weight loss rate is smaller than or equal to 1.5% after the wall protection plate is soaked in acid liquor, the bending retention rate is larger than or equal to 95.5%, and the use requirement of the wall protection plate in an acid scene is expanded.

Description

Technical Field

[0001] This invention belongs to the field of building decoration materials technology, specifically relating to a highly acid-resistant calcium carbonate modified wall panel and its preparation method. Background Technology

[0002] Calcium carbonate modified wall panels are a new type of building decoration material made of calcium carbonate as the main inorganic filler and compounded with polymer resin. Due to their low cost, good environmental performance, and excellent mechanical properties, they are widely used in interior and exterior wall decoration. Compared with traditional wood wall panels, they have advantages such as waterproofing, fire resistance, and insect resistance; compared with pure resin wall panels, the addition of calcium carbonate filler reduces raw material costs while improving the rigidity and dimensional stability of the panels.

[0003] However, calcium carbonate is an alkaline substance with unstable chemical properties. It easily reacts with acidic pollutants in the air, acidic cleaning detergents, and other acidic media, resulting in insufficient acid resistance in existing calcium carbonate modified wall panels in practical applications, and easily leading to the following defects:

[0004] Surface corrosion and powdering: Long-term contact with acidic environments will cause the calcium carbonate on the surface of the wall panel to decompose, resulting in pitting and powdering, which will affect the appearance quality.

[0005] Decreased mechanical properties: After the internal calcium carbonate particles are eroded, the structural integrity of the board is destroyed, resulting in a significant reduction in mechanical properties such as bending strength and impact resistance.

[0006] Shortened service life: The continuous erosion of acidic substances will trigger a chain reaction, accelerating the aging of the base resin and causing the wall panel to lose its function in a short period of time.

[0007] To address these issues, existing technologies often employ single surface modification methods to treat calcium carbonate, such as using silane coupling agents to improve compatibility with resins or using stearic acid for hydrophobic modification. However, these methods can only reduce the contact between calcium carbonate and acidic substances to a certain extent and cannot form an effective acid-resistant barrier, resulting in limited modification effects.

[0008] Therefore, in view of the above-mentioned problems in the existing technology, it is of great significance to develop a modification technology that can fundamentally improve the acid resistance of calcium carbonate while ensuring compatibility with the matrix and the overall performance of the board. This is of great significance for expanding the application scenarios of calcium carbonate modified wall panels (such as kitchens, bathrooms, and exterior walls in areas prone to acid rain). Summary of the Invention

[0009] In view of the deficiencies of the prior art, one object of the present invention is to provide a highly acid-resistant calcium carbonate modified wall panel, which aims to solve the technical problem of poor acid resistance of existing calcium carbonate modified wall panels.

[0010] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0011] The first objective of this invention is to provide a highly acid-resistant calcium carbonate modified wall panel, comprising the following components and their mass fractions:

[0012] 40-60 parts of matrix resin

[0013] 20-40 parts of composite modified calcium carbonate

[0014] 5-15 parts reinforcing fiber

[0015] Weather-resistant additives: 0.5-3 parts

[0016] Processing aids 1-5 parts;

[0017] The composite modified calcium carbonate is obtained by coating calcium carbonate with SiO2, then coupling it with a silane coupling agent, and finally grafting fluorinated acrylate segments onto it.

[0018] The matrix resin is selected from at least one of PVC resin, chlorinated polyethylene, or ethylene-vinyl acetate copolymer;

[0019] The reinforcing fiber is selected from at least one of glass fiber, basalt fiber or lignin fiber;

[0020] Preferably, the length of the reinforcing fiber is 0.5-5 mm;

[0021] The weather-resistant additives include ultraviolet absorbers and antioxidants;

[0022] The average particle size of the calcium carbonate is 5-10 μm;

[0023] Preferably, the weather-resistant additive comprises 0.1-1 parts by weight of an ultraviolet absorber and 0.2-1.5 parts by weight of an antioxidant;

[0024] Preferably, the ultraviolet absorber is selected from UV-531 or UV-327, and the antioxidant is selected from antioxidant 1010, antioxidant 168, or a mixture of the two.

[0025] The processing aids include lubricants, plasticizers, and impact modifiers;

[0026] Preferably, the processing aid comprises 0.5-2 parts by weight of lubricant, 0.3-1 parts by weight of plasticizer, and 0.2-2 parts by weight of impact modifier;

[0027] Preferably, the lubricant is zinc stearate or calcium stearate; the plasticizer is dioctyl phthalate; and the impact modifier is MBS resin.

[0028] The specific preparation steps of the composite modified calcium carbonate are as follows:

[0029] (1) Preparation of SiO2-coated calcium carbonate: Calcium carbonate powder is dispersed in deionized water, sodium silicate solution is added under stirring, pH is adjusted to 9-10, reaction is carried out at 60-80℃ for 1-2 hours, and SiO2-coated calcium carbonate is obtained after filtration and drying.

[0030] (2) Preparation of coupled SiO2-coated calcium carbonate: The SiO2-coated calcium carbonate obtained in step (1) is added to an ethanol aqueous solution, silane coupling agent KH-570 is added, and the mixture is stirred at 50-70℃ for 1-2 hours. After filtration and drying, coupled SiO2-coated calcium carbonate is obtained.

[0031] (3) Preparation of fluorine-containing segment grafted calcium carbonate: The SiO2-coated calcium carbonate obtained in step (2) is mixed with fluorine-containing acrylate monomer and initiator, and reacted at 70-90℃ for 2-4h under nitrogen protection. After cooling, it is washed and dried to obtain composite modified calcium carbonate.

[0032] Preferably, the amount of sodium silicate used is 5%-15% of the mass of calcium carbonate;

[0033] Preferably, the amount of KH-570 used is 1%-3% of the mass of calcium carbonate;

[0034] Preferably, the amount of the fluorinated acrylate monomer is 5%-20% of the mass of calcium carbonate, and the amount of the initiator is 0.5%-2% of the mass of the fluorinated acrylate monomer.

[0035] Preferably, the fluorinated acrylate monomer is a compound of short-chain fluorinated acrylate and long-chain fluorinated acrylate;

[0036] Preferably, the short-chain fluorinated acrylate is selected from trifluoroethyl acrylate or hexafluorobutyl acrylate;

[0037] Preferably, the long-chain fluoroacrylate is selected from tridecylfluorooctyl acrylate or heptadecafluorodecyl acrylate;

[0038] Preferably, the mass ratio of short-chain fluorinated acrylate to long-chain fluorinated acrylate is (1-2):1;

[0039] Preferably, the initiator is benzoyl peroxide;

[0040] This invention also provides a method for preparing a highly acid-resistant calcium carbonate modified wall panel, comprising the following steps:

[0041] S1. Weigh each raw material according to the weight proportions, add them to a high-speed mixer, and mix at 80-100℃ for 5-10 minutes to obtain a premix.

[0042] S2. Add the premixed material to a twin-screw extruder, melt-blend and extrude granulate at 160-190℃ to obtain composite granules, with a screw speed of 200-300 r / min;

[0043] S3. Add the composite granules into the board forming machine, and calender or extrude them at 170-185℃ and 10-20MPa. After cooling, a highly acid-resistant calcium carbonate modified wall panel is obtained.

[0044] The third objective of this invention is to provide an application of calcium carbonate modified wall panel in improving the acid resistance of wall panel.

[0045] Compared with the prior art, the present invention has the following advantages:

[0046] This invention creatively incorporates composite modified calcium carbonate into calcium carbonate-modified wall panels. The calcium carbonate is obtained by adding calcium carbonate that has been coated with SiO2, coupled with a silane coupling agent, and then grafted with fluorinated acrylate segments. This dual modification of calcium carbonate—"inorganic coating-organic grafting"—first uses the SiO2 coating layer as a physical barrier, utilizing its chemical inertness to block the direct reaction between calcium carbonate and acidic substances. Then, KH570 with double bonds is used to couple and modify SiO2. Finally, different fluorinated acrylate segments are covalently grafted onto the SiO2 surface, forming hydrophobic layers of different segment lengths. The intertwining of these different segment lengths reduces the wetting and penetration of acidic solutions on the particle surface, while simultaneously improving compatibility with the organic matrix resin. The dual modification synergistic effect significantly improves the acid resistance and dispersion stability of calcium carbonate in the matrix, resulting in calcium carbonate modified wall panels with better acid resistance. After soaking in acid solution, the weight loss rate is ≤1.5% and the bending retention rate is ≥95.5%. Detailed Implementation

[0047] Unless otherwise specified, the raw materials and equipment used in this invention are all commonly used in the field; unless otherwise specified, the methods used in this invention are all conventional methods in the field.

[0048] Unless otherwise specified, the terms used in this specification have the same meaning as those commonly understood by those skilled in the art; however, in the event of any conflict, the definitions in this specification shall prevail.

[0049] To better illustrate the purpose, technical solution, and advantages of the present invention, the present invention will be further described below in conjunction with specific embodiments.

[0050] Preparation of composite modified calcium carbonate

[0051] Preparation Example 1

[0052] Preparation of composite modified calcium carbonate A1:

[0053] (1) Calcium carbonate was dispersed in deionized water, and sodium silicate aqueous solution was added under stirring. The pH was adjusted to 9.5 with ammonia water, and the reaction was carried out at 80℃ for 2 hours. After filtration, the calcium carbonate was dried at 105℃ to obtain SiO2-coated calcium carbonate.

[0054] (2) Take the above SiO2-coated calcium carbonate, add it to an ethanol aqueous solution with a mass concentration of 30%, add KH-570, stir at 70℃ for 1.5h, filter and dry to obtain KH570-coupled SiO2-coated calcium carbonate.

[0055] (3) Trifluoroethyl acrylate, tridecylfluorooctyl acrylate, and benzoyl peroxide initiator were added to the SiO2-coated calcium carbonate coupled with KH570 obtained in step (2). The mixture was reacted at 80°C for 4 hours under nitrogen protection. After cooling, the mixture was washed three times with ethanol and dried at 100°C to obtain composite modified calcium carbonate A1.

[0056] The average particle size of calcium carbonate is 5-8 μm, the mass ratio of calcium carbonate to deionized water is 1:5, the mass concentration of sodium silicate in the sodium silicate aqueous solution is 10%, and the amount of sodium silicate used is 10% of the mass of calcium carbonate.

[0057] The mass ratio of SiO2-coated calcium carbonate to ethanol aqueous solution is 1:3, and the amount of KH570 used is 2% of the mass of calcium carbonate.

[0058] The total mass of trifluoroethyl acrylate and tridecylfluorooctyl acrylate is 5% of the mass of calcium carbonate, and the mass ratio of trifluoroethyl acrylate to tridecylfluorooctyl acrylate is 2:1.

[0059] The amount of initiator benzoyl peroxide is 0.5% of the total mass of trifluoroethyl acrylate and tridecafluorooctyl acrylate.

[0060] Preparation Example 2

[0061] Preparation of composite modified calcium carbonate A2:

[0062] (1) Calcium carbonate was dispersed in deionized water, and sodium silicate aqueous solution was added under stirring. The pH was adjusted to 9.5 with ammonia water, and the reaction was carried out at 80℃ for 2 hours. After filtration, the calcium carbonate was dried at 105℃ to obtain SiO2-coated calcium carbonate.

[0063] (2) Take the above SiO2-coated calcium carbonate, add it to an ethanol aqueous solution with a mass concentration of 30%, add KH-570, stir at 70℃ for 1.5h, filter and dry to obtain KH570-coupled SiO2-coated calcium carbonate.

[0064] (3) Add hexafluorobutyl acrylate, tridecafluorooctyl acrylate, and benzoyl peroxide as an initiator to the SiO2-coated calcium carbonate coupled with KH570 obtained in step (2). React at 80°C for 4 hours under nitrogen protection. After cooling, wash with ethanol 3 times and dry at 100°C to obtain composite modified calcium carbonate A2.

[0065] The average particle size of calcium carbonate is 5-8 μm, the mass ratio of calcium carbonate to deionized water is 1:5, the mass concentration of sodium silicate in the sodium silicate aqueous solution is 10%, and the amount of sodium silicate used is 10% of the mass of calcium carbonate.

[0066] The mass ratio of SiO2-coated calcium carbonate to ethanol aqueous solution is 1:3, and the amount of KH570 used is 2% of the mass of calcium carbonate.

[0067] The total mass of hexafluorobutyl acrylate and tridecylfluorooctyl acrylate is 5% of the mass of calcium carbonate, and the mass ratio of hexafluorobutyl acrylate to tridecylfluorooctyl acrylate is 2:1.

[0068] The amount of initiator benzoyl peroxide is 0.5% of the total mass of trifluoroethyl acrylate and tridecafluorooctyl acrylate.

[0069] Preparation Example 3

[0070] Preparation of composite modified calcium carbonate A3:

[0071] (1) Calcium carbonate was dispersed in deionized water, and sodium silicate aqueous solution was added under stirring. The pH was adjusted to 9.5 with ammonia water, and the reaction was carried out at 80℃ for 2 hours. After filtration, the calcium carbonate was dried at 105℃ to obtain SiO2-coated calcium carbonate.

[0072] (2) Take the above SiO2-coated calcium carbonate, add it to an ethanol aqueous solution with a mass concentration of 30%, add KH-570, stir at 70℃ for 1.5h, filter and dry to obtain KH570-coupled SiO2-coated calcium carbonate.

[0073] (3) Trifluoroethyl acrylate, tridecylfluorooctyl acrylate, and benzoyl peroxide initiator were added to the SiO2-coated calcium carbonate coupled with KH570 obtained in step (2). The mixture was reacted at 80°C for 4 hours under nitrogen protection. After cooling, the mixture was washed three times with ethanol and dried at 100°C to obtain composite modified calcium carbonate A3.

[0074] The average particle size of calcium carbonate is 5-8 μm, the mass ratio of calcium carbonate to deionized water is 1:5, the mass concentration of sodium silicate in the sodium silicate aqueous solution is 10%, and the amount of sodium silicate used is 10% of the mass of calcium carbonate.

[0075] The mass ratio of SiO2-coated calcium carbonate to ethanol aqueous solution is 1:3, and the amount of KH570 used is 2% of the mass of calcium carbonate.

[0076] The total mass of trifluoroethyl acrylate and tridecylfluorooctyl acrylate is 5% of the mass of calcium carbonate, and the mass ratio of trifluoroethyl acrylate to tridecylfluorooctyl acrylate is 1:1.

[0077] The amount of initiator benzoyl peroxide is 0.5% of the total mass of trifluoroethyl acrylate and tridecafluorooctyl acrylate.

[0078] Comparative Preparation Example 1

[0079] Preparation of composite modified calcium carbonate C1:

[0080] (1) Add calcium carbonate to an ethanol aqueous solution with a mass concentration of 30%, add KH-570, stir at 70℃ for 1.5h, filter and dry to obtain KH570 coupled calcium carbonate.

[0081] (2) Trifluoroethyl acrylate, tridecylfluorooctyl acrylate, and benzoyl peroxide initiator were added to the KH570-coupled calcium carbonate obtained in step (1). The mixture was reacted at 80°C for 4 hours under nitrogen protection. After cooling, the mixture was washed three times with ethanol and dried at 100°C to obtain composite modified calcium carbonate C1.

[0082] The average particle size of calcium carbonate is 5-8 μm.

[0083] The mass ratio of calcium carbonate to ethanol aqueous solution is 1:3, and the amount of KH570 used is 2% of the mass of calcium carbonate.

[0084] The total mass of trifluoroethyl acrylate and tridecylfluorooctyl acrylate is 5% of the mass of calcium carbonate, and the mass ratio of trifluoroethyl acrylate to tridecylfluorooctyl acrylate is 2:1.

[0085] The amount of initiator benzoyl peroxide is 0.5% of the total mass of trifluoroethyl acrylate and tridecafluorooctyl acrylate.

[0086] Comparative Preparation Example 2

[0087] Preparation of composite modified calcium carbonate C2:

[0088] (1) Calcium carbonate was dispersed in deionized water, and sodium silicate aqueous solution was added under stirring. The pH was adjusted to 9.5 with ammonia water, and the reaction was carried out at 80℃ for 2 hours. After filtration, the calcium carbonate was dried at 105℃ to obtain SiO2-coated calcium carbonate.

[0089] (2) Take the above SiO2-coated calcium carbonate, add trifluoroethyl acrylate and tridecylfluorooctyl acrylate, and initiator benzoyl peroxide. React at 80°C for 4 hours under nitrogen protection. After cooling, wash with ethanol 3 times and dry at 100°C to obtain composite modified calcium carbonate C2.

[0090] The average particle size of calcium carbonate is 5-8 μm, the mass ratio of calcium carbonate to deionized water is 1:5, the mass concentration of sodium silicate in the sodium silicate aqueous solution is 10%, and the amount of sodium silicate used is 10% of the mass of calcium carbonate.

[0091] The total mass of trifluoroethyl acrylate and tridecylfluorooctyl acrylate is 5% of the mass of calcium carbonate, and the mass ratio of trifluoroethyl acrylate to tridecylfluorooctyl acrylate is 2:1.

[0092] The amount of initiator benzoyl peroxide is 0.5% of the total mass of trifluoroethyl acrylate and tridecafluorooctyl acrylate.

[0093] Comparative preparation example 3

[0094] Preparation of composite modified calcium carbonate C3:

[0095] (1) Calcium carbonate was dispersed in deionized water, and sodium silicate aqueous solution was added under stirring. The pH was adjusted to 9.5 with ammonia water, and the reaction was carried out at 80℃ for 2 hours. After filtration, the calcium carbonate was dried at 105℃ to obtain SiO2-coated calcium carbonate.

[0096] (2) Take the above SiO2-coated calcium carbonate, add it to an ethanol aqueous solution with a mass concentration of 30%, add KH-570, stir at 70℃ for 1.5h, filter and dry to obtain KH570-coupled SiO2-coated calcium carbonate, which is the composite modified calcium carbonate C3.

[0097] The average particle size of calcium carbonate is 5-8 μm, the mass ratio of calcium carbonate to deionized water is 1:5, the mass concentration of sodium silicate in the sodium silicate aqueous solution is 10%, and the amount of sodium silicate used is 10% of the mass of calcium carbonate.

[0098] The mass ratio of SiO2-coated calcium carbonate to ethanol aqueous solution is 1:3, and the amount of KH570 used is 2% of the mass of calcium carbonate.

[0099] Comparative preparation example 4

[0100] Preparation of composite modified calcium carbonate C4:

[0101] (1) Calcium carbonate was dispersed in deionized water, and sodium silicate aqueous solution was added under stirring. The pH was adjusted to 9.5 with ammonia water, and the reaction was carried out at 80℃ for 2 hours. After filtration, the calcium carbonate was dried at 105℃ to obtain SiO2-coated calcium carbonate.

[0102] (2) Take the above SiO2-coated calcium carbonate, add it to an ethanol aqueous solution with a mass concentration of 30%, add KH-570, stir at 70℃ for 1.5h, filter and dry to obtain KH570-coupled SiO2-coated calcium carbonate.

[0103] (3) Trifluoroethyl acrylate and benzoyl peroxide initiator were added to the SiO2-coated calcium carbonate coupled with KH570 obtained in step (2). The mixture was reacted at 80°C for 4 hours under nitrogen protection. After cooling, it was washed three times with ethanol and dried at 100°C to obtain composite modified calcium carbonate C4.

[0104] The average particle size of calcium carbonate is 5-8 μm, the mass ratio of calcium carbonate to deionized water is 1:5, the mass concentration of sodium silicate in the sodium silicate aqueous solution is 10%, and the amount of sodium silicate used is 10% of the mass of calcium carbonate.

[0105] The mass ratio of SiO2-coated calcium carbonate to ethanol aqueous solution is 1:3, and the amount of KH570 used is 2% of the mass of calcium carbonate.

[0106] The mass of trifluoroethyl acrylate is 5% of the mass of calcium carbonate;

[0107] The amount of initiator benzoyl peroxide is 0.5% of the mass of trifluoroethyl acrylate.

[0108] Comparative preparation example 5

[0109] Preparation of composite modified calcium carbonate C5:

[0110] (1) Calcium carbonate was dispersed in deionized water, and sodium silicate aqueous solution was added under stirring. The pH was adjusted to 9.5 with ammonia water, and the reaction was carried out at 80℃ for 2 hours. After filtration, the calcium carbonate was dried at 105℃ to obtain SiO2-coated calcium carbonate.

[0111] (2) Take the above SiO2-coated calcium carbonate, add it to an ethanol aqueous solution with a mass concentration of 30%, add KH-570, stir at 70℃ for 1.5h, filter and dry to obtain KH570-coupled SiO2-coated calcium carbonate.

[0112] (3) Tridecafluorooctyl acrylate and benzoyl peroxide initiator were added to the SiO2-coated calcium carbonate coupled with KH570 obtained in step (2). The mixture was reacted at 80°C for 4 hours under nitrogen protection. After cooling, the mixture was washed three times with ethanol and dried at 100°C to obtain composite modified calcium carbonate C5.

[0113] The average particle size of calcium carbonate is 5-8 μm, the mass ratio of calcium carbonate to deionized water is 1:5, the mass concentration of sodium silicate in the sodium silicate aqueous solution is 10%, and the amount of sodium silicate used is 10% of the mass of calcium carbonate.

[0114] The mass ratio of SiO2-coated calcium carbonate to ethanol aqueous solution is 1:3, and the amount of KH570 used is 2% of the mass of calcium carbonate.

[0115] The mass of tridecafluorooctyl acrylate is 5% of the mass of calcium carbonate;

[0116] The amount of initiator benzoyl peroxide used is 0.5% of the mass of tridecafluorooctyl acrylate.

[0117] Comparative preparation example 6

[0118] Preparation of composite modified calcium carbonate C6:

[0119] (1) Calcium carbonate was dispersed in deionized water, and sodium silicate aqueous solution was added under stirring. The pH was adjusted to 9.5 with ammonia water, and the reaction was carried out at 80℃ for 2 hours. After filtration, the calcium carbonate was dried at 105℃ to obtain SiO2-coated calcium carbonate.

[0120] (2) Take the above SiO2-coated calcium carbonate, add it to an ethanol aqueous solution with a mass concentration of 30%, add KH-570, stir at 70℃ for 1.5h, filter and dry to obtain KH570-coupled SiO2-coated calcium carbonate.

[0121] (3) Trifluoroethyl acrylate, tridecylfluorooctyl acrylate, and benzoyl peroxide initiator were added to the SiO2-coated calcium carbonate coupled with KH570 obtained in step (2). The mixture was reacted at 80°C for 4 hours under nitrogen protection. After cooling, the mixture was washed three times with ethanol and dried at 100°C to obtain composite modified calcium carbonate C6.

[0122] The average particle size of calcium carbonate is 5-8 μm, the mass ratio of calcium carbonate to deionized water is 1:5, the mass concentration of sodium silicate in the sodium silicate aqueous solution is 10%, and the amount of sodium silicate used is 10% of the mass of calcium carbonate.

[0123] The mass ratio of SiO2-coated calcium carbonate to ethanol aqueous solution is 1:3, and the amount of KH570 used is 2% of the mass of calcium carbonate.

[0124] The total mass of trifluoroethyl acrylate and tridecylfluorooctyl acrylate is 5% of the mass of calcium carbonate, and the mass ratio of trifluoroethyl acrylate to tridecylfluorooctyl acrylate is 3:1.

[0125] The amount of initiator benzoyl peroxide is 0.5% of the total mass of trifluoroethyl acrylate and tridecafluorooctyl acrylate.

[0126] Comparative preparation example 7

[0127] Preparation of composite modified calcium carbonate C7:

[0128] (1) Calcium carbonate was dispersed in deionized water, and sodium silicate aqueous solution was added under stirring. The pH was adjusted to 9.5 with ammonia water, and the reaction was carried out at 80℃ for 2 hours. After filtration, the calcium carbonate was dried at 105℃ to obtain SiO2-coated calcium carbonate.

[0129] (2) Take the above SiO2-coated calcium carbonate, add it to an ethanol aqueous solution with a mass concentration of 30%, add KH-570, stir at 70℃ for 1.5h, filter and dry to obtain KH570-coupled SiO2-coated calcium carbonate.

[0130] (3) Methyl methacrylate and benzoyl peroxide initiator were added to the SiO2-coated calcium carbonate coupled with KH570 obtained in step (2). The mixture was reacted at 80°C for 4 hours under nitrogen protection. After cooling, it was washed three times with ethanol and dried at 100°C to obtain composite modified calcium carbonate C7.

[0131] The average particle size of calcium carbonate is 5-8 μm, the mass ratio of calcium carbonate to deionized water is 1:5, the mass concentration of sodium silicate in the sodium silicate aqueous solution is 10%, and the amount of sodium silicate used is 10% of the mass of calcium carbonate.

[0132] The mass ratio of SiO2-coated calcium carbonate to ethanol aqueous solution is 1:3, and the amount of KH570 used is 2% of the mass of calcium carbonate.

[0133] The mass of methacrylate is 5% of the mass of calcium carbonate;

[0134] The amount of initiator benzoyl peroxide is 0.5% of the mass of methacrylate.

[0135] Example 1

[0136] A method for preparing a highly acid-resistant calcium carbonate modified wall panel, comprising the following components and their mass fractions:

[0137] 50 parts of PVC resin (SG-5)

[0138] Composite modified calcium carbonate A1 30 parts

[0139] 10 parts of glass fiber (average length 3mm)

[0140] Weather-resistant additives (UV-531 0.5 parts, antioxidant 1010 0.6 parts, antioxidant 168 0.4 parts) 1.5 parts

[0141] Processing aids (1 part zinc stearate, 0.8 parts dioctyl phthalate, 1.2 parts MBS resin) 3 parts;

[0142] The preparation method of the above-mentioned highly acid-resistant calcium carbonate modified wall panel includes the following steps:

[0143] S1. Add all raw materials to a high-speed mixer and mix at 80°C for 5 minutes to obtain a premix.

[0144] S2. Add the premixed material to a twin-screw extruder and granulate it using the twin-screw extruder. The screw speed is 300 r / min, and the temperatures of each section are 165℃, 175℃, 185℃, and 180℃ to obtain composite granules.

[0145] S3. Add the composite granules into the board forming machine, and calender them at 180℃ and 20MPa. After cooling, a highly acid-resistant calcium carbonate modified wall panel is obtained.

[0146] Example 2-3

[0147] The composite modified calcium carbonate A1 in Example 1 was replaced with the composite modified calcium carbonate in Preparation Examples 2-3, while other aspects remained the same as in Example 1, to obtain the highly acid-resistant calcium carbonate modified wall panels of Examples 2-3.

[0148] Comparative Examples 1-7

[0149] The composite modified calcium carbonate A1 in Example 1 was replaced with the composite modified calcium carbonate in Comparative Preparation Examples 1-7, while other aspects remained the same as in Example 1, to obtain the calcium carbonate modified wall panels of Comparative Examples 1-7.

[0150] Comparative Example 8

[0151] The composite modified calcium carbonate A1 in Example 1 was replaced with unmodified calcium carbonate, while everything else remained the same as in Example 1, to obtain the calcium carbonate modified wall panel of Comparative Example 8.

[0152] Performance testing:

[0153] Acid resistance test

[0154] 1. Weight loss rate (%)

[0155] The weight loss rate of the calcium carbonate modified wall panels of the examples and comparative examples was tested after immersing them in 10% hydrochloric acid at room temperature for 24 hours.

[0156] 2. Bending strength retention rate (%)

[0157] Test standard: ASTM D790-2017

[0158] The flexural strength retention rate of the calcium carbonate modified wall panels of the examples and comparative examples was tested after immersing them in 30% H2SO4 at 80°C for 200 hours.

[0159] The test results are shown in Table 1 below:

[0160] Table 1

[0161]

[0162]

[0163] Comparing Examples 1-3 and Comparative Examples 1-8 in Table 1, it can be seen that the present invention modifies the wall panel by adding calcium carbonate obtained by coating with SiO2 and then coupling with a silane coupling agent and grafting fluorinated acrylate segments. Through the dual modification of calcium carbonate by "inorganic coating-organic grafting", the SiO2 coating layer is first used as a physical barrier to block the direct reaction between calcium carbonate and acidic substances by utilizing its chemical inertness. Then, KH570 with double bonds is used to couple and modify SiO2. Then, different fluorinated acrylate segments are grafted onto the SiO2 surface through covalent bonds to form a hydrophobic layer with segments of different lengths. The mutual entanglement of different segment lengths reduces the wetting and penetration of acidic solutions on the particle surface, while improving the compatibility with organic matrix resin. The dual modification synergistic effect significantly improves the acid resistance and dispersion stability of calcium carbonate in the matrix, resulting in calcium carbonate modified wall panels with better acid resistance. After soaking in acid solution, the weight loss rate is ≤1.5% and the bending retention rate is ≥95.5%.

[0164] Comparing Examples 1-3 and Comparative Examples 1-8 in Table 1, it can be seen that during the preparation of the composite modified calcium carbonate in the calcium carbonate modified wall panel of the present invention, the failure to use SiO2 coating, the failure to use KH570 coupling treatment, or the failure to use fluorinated acrylate for graft modification, as well as the use of only a single fluorinated acrylate or the failure to use fluorinated acrylate, all have an adverse effect on the acid resistance of the final calcium carbonate modified wall panel.

[0165] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the embodiments of the present invention and not to limit them. Although the embodiments of the present invention have been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the embodiments of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A highly acid-resistant calcium carbonate modified wall panel, characterized in that, Includes the following components and their mass fractions: 40-60 parts of matrix resin 20-40 parts of composite modified calcium carbonate 5-15 parts reinforcing fiber Weather-resistant additives: 0.5-3 parts Processing aids 1-5 parts; The composite modified calcium carbonate is obtained by coating calcium carbonate with SiO2, then coupling it with a silane coupling agent, and finally grafting fluorinated acrylate segments onto it.

2. The highly acid-resistant calcium carbonate modified wall panel according to claim 1, characterized in that, The specific preparation steps of the composite modified calcium carbonate are as follows: (1) Preparation of SiO2-coated calcium carbonate: Calcium carbonate powder is dispersed in deionized water, sodium silicate solution is added under stirring, pH is adjusted to 9-10, reaction is carried out at 60-80℃ for 1-2 hours, and SiO2-coated calcium carbonate is obtained after filtration and drying. (2) Preparation of coupled SiO2-coated calcium carbonate: The SiO2-coated calcium carbonate obtained in step (1) is added to an ethanol aqueous solution, silane coupling agent KH-570 is added, and the mixture is stirred at 50-70℃ for 1-2 hours. After filtration and drying, coupled SiO2-coated calcium carbonate is obtained. (3) Preparation of fluorine-containing segment grafted calcium carbonate: The SiO2-coated calcium carbonate obtained in step (2) is mixed with fluorine-containing acrylate monomer and initiator, and reacted at 70-90℃ for 2-4h under nitrogen protection. After cooling, it is washed and dried to obtain composite modified calcium carbonate.

3. The highly acid-resistant calcium carbonate modified wall panel according to claim 2, characterized in that, The amount of sodium silicate used is 5%-15% of the mass of calcium carbonate; The amount of KH-570 used is 1%-3% of the mass of calcium carbonate; The amount of the fluorinated acrylate monomer used is 5%-20% of the mass of calcium carbonate, and the amount of the initiator used is 0.5%-2% of the mass of the fluorinated acrylate monomer.

4. The highly acid-resistant calcium carbonate modified wall panel according to claim 3, characterized in that, The fluorinated acrylate monomer is a compound of short-chain fluorinated acrylate and long-chain fluorinated acrylate; The mass ratio of the short-chain acrylate to the long-chain acrylate is (1-2):1; The initiator is benzoyl peroxide.

5. The highly acid-resistant calcium carbonate modified wall panel according to claim 4, characterized in that, The short-chain fluoroacrylate is selected from trifluoroethyl acrylate or hexafluorobutyl acrylate; The long-chain fluoroacrylate is selected from tridecylfluorooctyl acrylate or heptadecafluorodecyl acrylate.

6. The highly acid-resistant calcium carbonate modified wall panel according to claim 1, characterized in that, The matrix resin is selected from at least one of PVC resin, chlorinated polyethylene, or ethylene-vinyl acetate copolymer; The reinforcing fiber is selected from at least one of glass fiber, basalt fiber or lignin fiber; The weather-resistant additives include ultraviolet absorbers and antioxidants; The average particle size of the calcium carbonate is 5-10 μm; The processing aids include lubricants, plasticizers, and impact modifiers.

7. The highly acid-resistant calcium carbonate modified wall panel according to claim 6, characterized in that, The length of the reinforcing fiber is 0.5-5 mm; The weather-resistant additive includes 0.1-1 parts by weight of an ultraviolet absorber and 0.2-1.5 parts by weight of an antioxidant; The ultraviolet absorber is selected from UV-531 or UV-327, and the antioxidant is selected from antioxidant 1010, antioxidant 168 or a mixture of the two. The processing aids include 0.5-2 parts by weight of lubricant, 0.3-1 parts by weight of plasticizer, and 0.2-2 parts by weight of impact modifier; The lubricant is zinc stearate or calcium stearate; the plasticizer is dioctyl phthalate; and the impact modifier is MBS resin.

8. A method for preparing a highly acid-resistant calcium carbonate modified wall panel according to any one of claims 1-7, characterized in that, Includes the following steps: S1. Weigh each raw material according to the weight proportions, add them to a high-speed mixer, and mix at 80-100℃ for 5-10 minutes to obtain a premix. S2. Add the premixed material to a twin-screw extruder, melt-blend and extrude granulate at 160-190℃ to obtain composite granules, with a screw speed of 200-300 r / min; S3. Add the composite granules into the board forming machine, and calender or extrude them at 170-185℃ and 10-20MPa. After cooling, a highly acid-resistant calcium carbonate modified wall panel is obtained.

9. The application of a highly acid-resistant calcium carbonate modified wall panel obtained by the preparation method of the highly acid-resistant calcium carbonate modified wall panel according to any one of claims 1-7 or claim 8 in improving the acid resistance of the wall panel.

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