Special emulsion for large-particle-size high-air-permeability soft porcelain as well as preparation method and application of special emulsion

Abstract

The invention belongs to the technical field of building materials, and discloses a special emulsion for large-particle-size high-air-permeability soft porcelain and a preparation method and application thereof, and the emulsion comprises a seed phase, a core emulsion phase, a hard-shell pre-emulsion phase, an initiation system and a post-treatment auxiliary agent; the core emulsion phase comprises deionized water, 2-ethylhexyl acrylate, glycidyl methacrylate, a toughening aid, ethyl phosphate methacrylate and an OP-10 emulsifier; the toughening aid is a polyether-polyester block copolymer; the post-treatment auxiliary agent comprises an antibacterial flame retardant, an organic silicon defoaming agent and ammonia water, the antibacterial flame retardant is a benzisothiazolinone derivative containing phosphorus and nitrogen, performance complementation is achieved through the layered design of a core-shell structure, and meanwhile the stability and adhesive force are improved by means of the reactive emulsifier and the functional monomer; in addition, the polyether polyester block type reactive toughening aid and the phosphorus and nitrogen-containing benzisothiazolinone derivative antibacterial flame retardant are added, so that synergistic optimization of toughening, antibacterial and flame retardant is realized.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of building materials, and particularly relates to a large-particle-size high-air-permeability soft porcelain special emulsion as well as a preparation method and application thereof. BACKGROUND

[0002] Soft porcelain is a new type of building decoration material, which has the advantages of light weight, flexibility, strong stone-like texture, convenient construction, etc., and is widely used in the fields of interior and exterior wall decoration, floor paving, etc. The preparation of soft porcelain usually takes high molecular emulsion as a binder, which is mixed with sand powder, fillers, etc. and then is formed, dried, embossed and the like to be made. The existing soft porcelain emulsion is prepared by a semi-continuous seed emulsion polymerization method, and can be divided into two types of basic type and functional type according to the functional positioning: (1) the basic type emulsion takes methyl methacrylate (MMA) as a hard shell monomer and butyl acrylate (BA) or 2-ethylhexyl acrylate (2-EHA) as a soft core monomer, and the basic mechanical properties of soft porcelain are controlled by adjusting the mass ratio of the core-shell (usually 1:1~2:1), which is mainly used for ordinary building exterior wall decoration, accounting for about 70% of the market share; (2) the functional type emulsion introduces a small amount of functional monomers (such as hydroxy acrylate HEA, carboxyl acrylate AA) or additives (such as organosilane, nano silicon dioxide) in the basic formula to improve the water resistance, stain resistance and other single properties, which is mainly used in humid environments (such as bathrooms) or high-end decoration scenes, accounting for about 30%.

[0003] The glass transition temperature of the existing emulsion soft core monomer (such as BA) is about -54℃, but due to the limitation of the core-shell interface compatibility, the actual soft porcelain is prone to hard shell brittle fracture and soft core toughness loss below -15℃. At the same time, the functional improvement of the existing soft porcelain emulsion mostly adopts a single additive compounding mode, which has compatibility and durability problems. In addition, in order to pursue water resistance, the existing emulsion mostly adopts a small particle size (80~120nm) and high crosslinking degree design, which leads to poor air permeability of the soft porcelain after film formation. Therefore, it is urgent to develop a large-particle-size high-air-permeability soft porcelain special emulsion. SUMMARY

[0004] In order to solve the problems mentioned in the background, the purpose of the present application is to provide a large-particle-size high-air-permeability soft porcelain special emulsion as well as a preparation method and application thereof, which realizes performance complementation through the layered design of the core-shell structure, improves the stability and adhesion by means of reactive emulsifiers and functional monomers, and realizes the synergistic optimization of toughening, antibacterial and flame retardant by adding polyether polyester block type reactive toughening additives and benzisothiazolinone derivative antibacterial flame retardant containing phosphorus and nitrogen.

[0005] The purpose of the present application can be realized by the following technical solutions: A large-particle-size high-air-permeability soft porcelain special emulsion, the emulsion comprising: Seed phase: 40-45 parts deionized water, 1.2-1.5 parts ethyl methacrylate, 8-10 parts methyl methacrylate, 0.3-0.5 parts sodium bicarbonate; Nuclear emulsion phase: 30-35 parts deionized water, 35-40 parts isooctyl acrylate, 2-3 parts glycidyl methacrylate, 3-5 parts toughening agent, 0.8-1 part ethyl methacrylate, 0.3-0.5 parts OP-10 emulsifier; Hard-shell preemulsion phase: 45-50 parts deionized water, 25-30 parts methyl methacrylate, 7-8.4 parts styrene, 3-3.6 parts isobornyl methacrylate, 1.5-2.0 parts acrylic acid, 1.0-1.5 parts hydroxyethyl acrylate, 0.8-1.2 parts N-hydroxymethylacrylamide, 1.5-2.0 parts hydroxypropyl methacrylate, 1.0-1.2 parts ethyl methacrylate, and 0.5-0.8 parts allyl polyoxyethylene ether; Initiation system: 10-20 parts deionized water, 0.6-0.8 parts ammonium persulfate, 0.15-0.25 parts sodium bisulfite, and 0.15-0.25 parts tert-butyl hydroperoxide; Post-treatment additives: 0.3-0.5 parts antibacterial flame retardant, 0.2-0.3 parts silicone defoamer, and 3-5 parts ammonia. The toughening agent is a polyether-polyester block copolymer, which adopts a polyethylene glycol monomethyl ether-polybutylene adipate block structure, with hydroxyethyl methacrylate connected to both ends by isocyanate. The antibacterial flame retardant is a phosphorus and nitrogen-containing benzisothiazolinone derivative, which is obtained by introducing an active chloromethyl group through chloromethylation of 1,2-benzisothiazol-3-one, followed by nucleophilic substitution reaction of the chloromethyl group with diethyl phosphite.

[0006] Preferably, the method for preparing the toughening agent includes the following steps: (1) Polyethylene glycol monomethyl ether and polybutylene adipate were added to the reactor, heated to 80~85℃, vacuum dehydrated for 0.5~1.5h, cooled to 60℃, hexamethylene diisocyanate and dibutyltin dilaurate were added, and the temperature was slowly raised to 80~85℃ under nitrogen protection and kept at the temperature for 2~3h to obtain a block prepolymer containing -NCO at both ends; (2) Cool the above block prepolymer to 50~55℃, add hydroxyethyl methacrylate and hydroquinone, stir evenly, then heat to 70~75℃ and keep the reaction at this temperature for 1.5~2.5h to obtain the crude product of block copolymer; (3) Cool the crude block copolymer product to 40°C, add 30% of the crude product mass of ethyl acetate to dissolve it, then pour it into 5 times the volume of deionized water, stir for 20-40 min, let it stand and separate into layers, discard the aqueous phase, wash the organic phase with deionized water 3-5 times, and then remove ethyl acetate under vacuum to obtain the toughening agent.

[0007] Preferably, the mass ratio of polyethylene glycol monomethyl ether, polybutylene adipate, and hexamethylene diisocyanate is 8:7:2, and the amount of dibutyltin dilaurate is 1% to 1.5% of the mass of hexamethylene diisocyanate.

[0008] Preferably, the mass ratio of hydroxyethyl methacrylate to hexamethylene diisocyanate is 3:5, and the amount of hydroquinone used is 0.5% to 1% of the mass of hydroxyethyl methacrylate.

[0009] Preferably, the preparation method of the antibacterial flame retardant includes the following steps: A. Add 1,2-benzisothiazol-3-one to concentrated hydrochloric acid, place in an ice bath at 0-5°C, slowly add formaldehyde aqueous solution, remove the ice bath after the addition is complete, stir the reaction at room temperature for 6-8 hours, after the reaction is complete, slowly pour the reaction solution into ice water to precipitate solid product, filter and wash the solid thoroughly with cold water, and vacuum dry to obtain intermediate A. B. Add intermediate A to anhydrous acetonitrile, and under nitrogen protection and ice-water bath cooling, slowly add a suspension made of potassium carbonate and anhydrous acetonitrile, then slowly add diethyl phosphite. After the addition is complete, raise the temperature to 70-80°C and reflux for 8-12 hours. After the reaction is complete, cool to room temperature, filter to remove inorganic salts, concentrate the filtrate under reduced pressure, and then purify by column chromatography to obtain the antibacterial flame retardant.

[0010] Preferably, the mass ratio of 1,2-benzisothiazol-3-one to formaldehyde is 5:1.

[0011] Preferably, the mass ratio of intermediate A, potassium carbonate, and diethyl phosphite is 5:4:4.

[0012] A method for preparing a large-particle-size, highly permeable emulsion for soft porcelain includes the following steps: S1. Seed phase preparation: Add deionized water to the reaction vessel, heat to 80℃, purge with nitrogen for protection, start stirring, and add ethyl methacrylate, methyl methacrylate and sodium bicarbonate in sequence. After the addition is completed, keep warm for 20-40 min. S2. Preparation of core emulsion phase: Deionized water, isooctyl acrylate, glycidyl methacrylate, toughening agent, ethyl phosphate methacrylate, and OP-10 emulsifier are mixed and pre-emulsified to obtain core emulsion phase; S3. Preparation of hard-shell preemulsion phase: Deionized water, methyl methacrylate, styrene, isobornyl methacrylate, acrylic acid, hydroxyethyl acrylate, N-hydroxymethylacrylamide, hydroxypropyl methacrylate, ethyl phosphate methacrylate, and allyl polyoxyethylene ether are mixed and preemulsified to obtain a hard-shell preemulsion phase. S4. Deionized water, ammonium persulfate, sodium bisulfite, and tert-butyl hydroperoxide were mixed to obtain an initiation system. The initiation system was then added dropwise to the reactor simultaneously with the core emulsion phase and the hard shell pre-emulsion phase at 75°C. After all the initiation system was added, the reactor was kept at 70°C for 0.5 to 1.5 hours to mature. S5. Cool to room temperature, add antibacterial flame retardant and organosilicon defoamer and stir evenly, adjust pH to 8-9 with ammonia water, filter and discharge to obtain the large particle size high air permeability soft porcelain special emulsion.

[0013] Preferably, in step S4, half of the initiation system and the core emulsion phase are added dropwise to the reactor simultaneously. After the core emulsion phase is added, the other half of the initiation system and the hard-shell pre-emulsion phase are added dropwise to the reactor simultaneously.

[0014] An application of a special emulsion for large-particle-size, high-permeability flexible ceramics involves mixing the emulsion with sand powder at a ratio of 1:3, molding the mixture, and then drying it in an oven at 90-110℃ to obtain large-particle-size, high-permeability flexible ceramics. The finished product is free of bubbles and skin, demolds smoothly, has a smooth surface, good toughness, good low-temperature toughness, and antibacterial and flame-retardant effects, making it suitable for flexible ceramic engineering projects with high requirements for safety and environmental adaptability.

[0015] The beneficial effects of this invention are: This invention presents a core-shell structure design for a large-particle-size, highly permeable emulsion specifically for flexible ceramics. Through a compound system of anionic nonionic reactive emulsifiers, the introduction of polar monomers, particle size control (150–200 nm), and the use of azeotropic monomers, the film-forming permeability, adhesion strength to sintered clay powder, and high-temperature drying efficiency of the emulsion are significantly improved. Furthermore, the addition of a polyether polyester block-type reactive toughening agent and a phosphorus- and nitrogen-containing benzisothiazolinone derivative antibacterial and flame-retardant achieves synergistic optimization of toughening, antibacterial properties, and flame retardancy, making it particularly suitable for flexible ceramic engineering projects with high requirements for safety and environmental adaptability.

[0016] In this invention, the emulsion core layer uses 2-EHA as the main monomer to provide a soft inner core, giving the flexible ceramic good flexibility and crack resistance. MMA and St are used as the main monomers to form a hard outer shell, ensuring the stiffness and scrub resistance of the flexible ceramic. Reactive emulsifiers (such as ethyl methacrylate) are used to avoid performance degradation caused by migration of traditional emulsifiers, improving the adhesion between the emulsion and the substrate. A pH buffer and a post-treatment pH adjuster are introduced to maintain system stability and prevent demulsification during storage. Persulfate initiation and redox post-treatment are employed to ensure sufficient monomer polymerization and reduce the impact of residual monomers on the environmental friendliness of the flexible ceramic. Polar functional monomers (AA, AM, HEA) increase the polarity of the emulsion, improving adhesion to inorganic substrates (such as cement substrates). Azoborosilicate modifiers (HPMA) optimize the boiling point balance during polymerization, reducing bubble generation and ensuring the smoothness of the flexible ceramic surface.

[0017] The toughening agent of this invention adopts a block structure of polyethylene glycol monomethyl ether (PEO) and polybutylene adipate (PBA), with hydroxyethyl methacrylate linked to both ends by isocyanate. The PEO segments have excellent low-temperature fluidity and can still rotate freely below -20°C, providing molecular-level lubrication. The PBA segments have good compatibility with the core layer soft monomer 2-EHA, enhancing the entanglement between segments and preventing the molecular chain from becoming rigid at low temperatures. The double bonds at both ends can copolymerize with the core layer monomers (2-EHA, GMA) to form covalent anchoring, completely solving the migration problem of traditional plasticizers.

[0018] This invention's antibacterial and flame-retardant agent uses 1,2-benzisothiazol-3-one (BIT) as the parent compound. An active chloromethyl group is introduced through chloromethylation, followed by a nucleophilic substitution reaction with diethyl phosphite to form a phosphorus-nitrogen heterocyclic structure. The isothiazolinone ring of BIT is retained, achieving highly efficient antibacterial activity by disrupting microbial cell membrane proteins. The phosphorus group forms a phosphate ester flame-retardant coating at high temperatures, while nitrogen promotes char formation; both synergistically enhance the flame retardancy of flexible ceramics. Simultaneously, the ester groups in the molecule form hydrogen bonds with the hydroxyl and carboxyl groups of the polar monomers (HEA, AA) in the hard shell layer, without affecting the emulsion stability. This agent can replace traditional bactericides, simultaneously achieving antibacterial and flame-retardant effects, solving the problem of mold growth and fire risk in humid environments for flexible ceramics.

[0019] Of course, any product implementing this invention does not necessarily need to achieve all of the advantages described above at the same time. 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] Example 1

[0022] A toughening agent, wherein the toughening agent is a polyether-polyester block copolymer, adopting a polyethylene glycol monomethyl ether-polybutylene adipate block structure, with hydroxyethyl methacrylate linked to both ends by isocyanate, and its preparation method includes the following steps: (1) Add 40g of polyethylene glycol monomethyl ether and 35g of polybutylene adipate to the reactor, heat to 80~85℃, vacuum dehydrate for 0.5~1.5h, cool to 60℃, add 10g of hexamethylene diisocyanate and 0.1g of dibutyltin dilaurate, slowly heat to 80~85℃ under nitrogen protection, keep the reaction for 2~3h, use di-n-butylamine titration to detect the -NCO content, stop the reaction when the -NCO content drops to 50% of the theoretical value, and obtain a block prepolymer containing -NCO at both ends; (2) Cool the above block prepolymer to 50~55℃, add 6g hydroxyethyl methacrylate and 0.05g hydroquinone, stir evenly and then heat to 70~75℃, keep the temperature for 1.5~2.5h, detect the -NCO content, and stop the reaction when the -NCO content is ≤0.5% to obtain the crude product of block copolymer; (3) Cool the crude block copolymer product to 40°C, add 30% of the crude product mass of ethyl acetate to dissolve it, then pour it into 5 times the volume of deionized water, stir for 20-40 min, let it stand and separate into layers, discard the aqueous phase, wash the organic phase with deionized water 3-5 times, and then remove ethyl acetate under vacuum to obtain the toughening agent.

[0023] Example 2

[0024] An antibacterial flame retardant, wherein the antibacterial flame retardant is a phosphorus and nitrogen-containing benzisothiazolinone derivative, is prepared by introducing an active chloromethyl group through chloromethylation of 1,2-benzisothiazol-3-one, followed by a nucleophilic substitution reaction of the chloromethyl group with diethyl phosphite. The preparation method includes the following steps: A. Add 10.0 g of 1,2-benzisothiazol-3-one to 100 mL of concentrated hydrochloric acid. In an ice bath at 0-5 °C, slowly add 5.0 mL of 40 wt% formaldehyde aqueous solution. After the addition is complete, remove the ice bath and stir the reaction at room temperature for 6-8 h. After the reaction is complete, slowly pour the reaction solution into ice water to precipitate the solid product. Filter the solid and wash it thoroughly with cold water. Dry it under vacuum to obtain intermediate A. B. Add 5.0 g of intermediate A to 30 mL of anhydrous acetonitrile. Under nitrogen protection and ice-water bath cooling, slowly add a suspension made of 3.8 g of potassium carbonate and 10 mL of anhydrous acetonitrile, then slowly add 4.2 g of diethyl phosphite. After the addition is complete, raise the temperature to 70-80 °C and reflux for 8-12 h. After the reaction is complete, cool to room temperature, filter to remove inorganic salts, concentrate the filtrate under reduced pressure, and then purify by column chromatography to obtain the antibacterial flame retardant.

[0025] Example 3

[0026] A large-particle-size, highly permeable emulsion specifically for flexible porcelain, comprising: Seed phase: 40 parts deionized water, 1.5 parts ethyl methacrylate, 8 parts methyl methacrylate, 0.5 parts sodium bicarbonate; Nuclear emulsion phase: 35 parts deionized water, 40 parts isooctyl acrylate, 2 parts glycidyl methacrylate, 5 parts toughening agent, 0.8 parts ethyl methacrylate, and 0.5 parts OP-10 emulsifier; Hard-shell pre-emulsion phase: 45 parts deionized water, 30 parts methyl methacrylate, 7 parts styrene, 3.6 parts isobornyl methacrylate, 1.5 parts acrylic acid, 1.5 parts hydroxyethyl acrylate, 0.8 parts N-hydroxymethylacrylamide, 2.0 parts hydroxypropyl methacrylate, 1.0 part ethyl methacrylate, and 0.8 parts allyl polyoxyethylene ether; Initiation system: 10 parts deionized water, 0.8 parts ammonium persulfate, 0.15 parts sodium bisulfite, and 0.25 parts tert-butyl hydroperoxide; Post-treatment additives: 0.3 parts antibacterial flame retardant, 0.3 parts silicone defoamer, and 3 parts ammonia. The toughening agent is the polyether-polyester block copolymer prepared in Example 1; the antibacterial flame retardant is a phosphorus and nitrogen-containing benzisothiazolinone derivative prepared in Example 2.

[0027] The preparation method of the above-mentioned large-particle-size, highly permeable emulsion for soft porcelain includes the following steps: S1. Seed phase preparation: Add deionized water to the reaction vessel, heat to 80℃, purge with nitrogen for protection, start stirring, and add ethyl methacrylate, methyl methacrylate and sodium bicarbonate in sequence. After the addition is completed, keep warm for 40 min. S2. Preparation of core emulsion phase: Deionized water, isooctyl acrylate, glycidyl methacrylate, toughening agent, ethyl phosphate methacrylate, and OP-10 emulsifier are mixed and pre-emulsified to obtain core emulsion phase; S3. Preparation of hard-shell preemulsion phase: Deionized water, methyl methacrylate, styrene, isobornyl methacrylate, acrylic acid, hydroxyethyl acrylate, N-hydroxymethylacrylamide, hydroxypropyl methacrylate, ethyl phosphate methacrylate, and allyl polyoxyethylene ether are mixed and preemulsified to obtain a hard-shell preemulsion phase. S4. Deionized water, ammonium persulfate, sodium bisulfite and tert-butyl hydroperoxide were mixed to obtain an initiation system. The initiation system was then added dropwise to the reactor at 75°C along with the core emulsion phase and the hard shell pre-emulsion phase. After all the additions were completed, the reactor was kept at 70°C for 0.5 h to mature. S5. Cool to room temperature, add antibacterial flame retardant and organosilicon defoamer and stir evenly, adjust pH to 8-9 with ammonia water, filter and discharge to obtain the large particle size high air permeability soft porcelain special emulsion.

[0028] Example 4

[0029] A large-particle-size, highly permeable emulsion specifically for flexible porcelain, comprising: Seed phase: 45 parts deionized water, 1.2 parts ethyl methacrylate, 10 parts methyl methacrylate, 0.3 parts sodium bicarbonate; Nuclear emulsion phase: 35 parts deionized water, 35 parts isooctyl acrylate, 3 parts glycidyl methacrylate, 3 parts toughening agent, 1 part ethyl phosphate methacrylate, 0.3 parts OP-10 emulsifier; Hard-shell pre-emulsion phase: 50 parts deionized water, 25 parts methyl methacrylate, 8.4 parts styrene, 3 parts isobornyl methacrylate, 2.0 parts acrylic acid, 1.0 part hydroxyethyl acrylate, 1.2 parts N-hydroxymethylacrylamide, 1.5 parts hydroxypropyl methacrylate, 1.2 parts ethyl methacrylate, and 0.5 parts allyl polyoxyethylene ether; Initiation system: 20 parts deionized water, 0.6 parts ammonium persulfate, 0.25 parts sodium bisulfite, and 0.15 parts tert-butyl hydroperoxide; Post-treatment aids: 0.5 parts antibacterial flame retardant, 0.2 parts silicone defoamer, and 5 parts ammonia. The toughening agent is the polyether-polyester block copolymer prepared in Example 1; the antibacterial flame retardant is a phosphorus and nitrogen-containing benzisothiazolinone derivative prepared in Example 2.

[0030] The preparation method of the above-mentioned large-particle-size, highly permeable soft porcelain emulsion is the same as in Example 3.

[0031] Example 5

[0032] A large-particle-size, highly permeable emulsion specifically for flexible porcelain, comprising: Seed phase: 42.5 parts deionized water, 1.3 parts ethyl methacrylate, 9 parts methyl methacrylate, 0.4 parts sodium bicarbonate; Nuclear emulsion phase: 32.5 parts deionized water, 37.5 parts isooctyl acrylate, 2.5 parts glycidyl methacrylate, 4 parts toughening agent, 0.9 parts ethyl methacrylate, and 0.4 parts OP-10 emulsifier; Hard-shell preemulsion phase: 47.5 parts deionized water, 27.5 parts methyl methacrylate, 7.8 parts styrene, 3.3 parts isobornyl methacrylate, 1.8 parts acrylic acid, 1.2 parts hydroxyethyl acrylate, 1.0 part N-hydroxymethylacrylamide, 1.8 parts hydroxypropyl methacrylate, 1.1 parts ethyl methacrylate, and 0.6 parts allyl polyoxyethylene ether; Initiation system: 15 parts deionized water, 0.7 parts ammonium persulfate, 0.2 parts sodium bisulfite, and 0.2 parts tert-butyl hydroperoxide; Post-treatment aids: 0.4 parts antibacterial flame retardant, 0.25 parts silicone defoamer, and 4 parts ammonia. The toughening agent is the polyether-polyester block copolymer prepared in Example 1; the antibacterial flame retardant is a phosphorus and nitrogen-containing benzisothiazolinone derivative prepared in Example 2.

[0033] The preparation method of the above-mentioned large-particle-size, highly permeable soft porcelain emulsion is the same as in Example 3.

[0034] Comparative Example 1 A large-particle-size, highly permeable emulsion specifically for flexible porcelain, comprising: Seed phase: 42.5 parts deionized water, 1.3 parts ethyl methacrylate, 9 parts methyl methacrylate, 0.4 parts sodium bicarbonate; Nuclear emulsion phase: 32.5 parts deionized water, 37.5 parts isooctyl acrylate, 2.5 parts glycidyl methacrylate, 0.9 parts ethyl methacrylate, and 0.4 parts OP-10 emulsifier; Hard-shell preemulsion phase: 47.5 parts deionized water, 27.5 parts methyl methacrylate, 7.8 parts styrene, 3.3 parts isobornyl methacrylate, 1.8 parts acrylic acid, 1.2 parts hydroxyethyl acrylate, 1.0 part N-hydroxymethylacrylamide, 1.8 parts hydroxypropyl methacrylate, 1.1 parts ethyl methacrylate, and 0.6 parts allyl polyoxyethylene ether; Initiation system: 15 parts deionized water, 0.7 parts ammonium persulfate, 0.2 parts sodium bisulfite, and 0.2 parts tert-butyl hydroperoxide; Post-treatment aids: 0.15 parts antibacterial flame retardant, 0.25 parts silicone defoamer, and 4 parts ammonia. The antibacterial flame retardant is a phosphorus- and nitrogen-containing benzisothiazolinone derivative prepared in Example 2.

[0035] The preparation method of the above-mentioned large-particle-size, highly permeable soft porcelain emulsion is the same as that in Example 3, except that no toughening agent is added during the preparation of the core emulsion phase in step S2.

[0036] Comparative Example 2 A large-particle-size, highly permeable emulsion specifically for flexible porcelain, comprising: Seed phase: 42.5 parts deionized water, 1.3 parts ethyl methacrylate, 9 parts methyl methacrylate, 0.4 parts sodium bicarbonate; Nuclear emulsion phase: 32.5 parts deionized water, 37.5 parts isooctyl acrylate, 2.5 parts glycidyl methacrylate, 4 parts toughening agent, 0.9 parts ethyl methacrylate, and 0.4 parts OP-10 emulsifier; Hard-shell preemulsion phase: 47.5 parts deionized water, 27.5 parts methyl methacrylate, 7.8 parts styrene, 3.3 parts isobornyl methacrylate, 1.8 parts acrylic acid, 1.2 parts hydroxyethyl acrylate, 1.0 part N-hydroxymethylacrylamide, 1.8 parts hydroxypropyl methacrylate, 1.1 parts ethyl methacrylate, and 0.6 parts allyl polyoxyethylene ether; Initiation system: 15 parts deionized water, 0.7 parts ammonium persulfate, 0.2 parts sodium bisulfite, and 0.2 parts tert-butyl hydroperoxide; Post-treatment aids: 0.25 parts silicone defoamer, 4 parts ammonia; The toughening agent is the polyether-polyester block copolymer prepared in Example 1.

[0037] The preparation method of the above-mentioned large-particle-size, highly breathable soft porcelain emulsion is the same as that in Example 3, except that no antibacterial flame retardant is added in step S5.

[0038] Example 6

[0039] A type of large-particle-size, highly permeable soft porcelain is obtained by mixing the special emulsion for large-particle-size, highly permeable soft porcelain prepared in Example 5 with sand powder at a ratio of 1:3, molding it, and then drying it in an oven at 100°C.

[0040] Comparative Example 3 A type of large-particle-size, highly permeable soft porcelain is obtained by mixing the special emulsion for large-particle-size, highly permeable soft porcelain prepared in Comparative Example 1 with sand powder at a ratio of 1:3, molding the mixture, and then drying it in an oven at 100°C.

[0041] Comparative Example 4 A type of large-particle-size, highly permeable soft porcelain is obtained by mixing the special emulsion for large-particle-size, highly permeable soft porcelain prepared in Comparative Example 2 with sand powder at a ratio of 1:3, molding, and drying in an oven at 100°C.

[0042] Performance testing I. Physical and chemical properties testing of emulsions The emulsions prepared in Example 5, Comparative Example 1, and Comparative Example 2 were subjected to the following performance tests: (1) The particle size and distribution of the emulsion were tested using a dynamic light scattering instrument. The dynamic light scattering method was used. 10 μL of each group of emulsion samples were taken and diluted to 1 mL with deionized water (dilution ratio 1:100). 500 μL of the diluted sample was injected into a quartz cuvette, the water stains on the outer wall were wiped off, and the sample cell was placed in the sample cell. The test program was started. The instrument recorded the average particle size (Z-average) and particle size distribution span (PDI, i.e. D90 / D10) of each group of samples. The average value of 3 tests was taken. (2) The Zeta potential of the emulsion was tested using a dynamic light scattering instrument. Laser Doppler electrophoresis was used. 50 μL of each group of emulsion samples were taken and diluted to 1 mL with deionized water (dilution ratio 1:20). The diluted sample was injected into the electrophoresis sample cell, the electrode was inserted, and the sample was placed in the test chamber. The program was started, the instrument recorded the electrophoretic trajectory of the particles and calculated the Zeta potential. The average value of the three tests was taken as the final Zeta potential. (3) Centrifugation stability test: Take 25g of each group of emulsion samples and inject them into 50mL centrifuge tubes. Record the initial volume of the sample V0. Place the centrifuge tubes symmetrically into the centrifuge rotor, tighten the cap, start the centrifugation program, and slowly remove the centrifuge tubes after centrifugation. Observe the stratification of the sample in the centrifuge tube (the upper layer is clear liquid / dilute emulsion, and the lower layer is precipitate / concentrated emulsion). Record the volume of the upper clear liquid V1. Calculate the stratification rate according to the formula: stratification rate (%) = (V1 / V0) × 100%. Test each sample 3 times and take the average value. (4) Thermal stability test: The emulsion was aged at high temperature (50℃) and the viscosity change of the emulsion after storage was detected to evaluate the emulsion’s resistance to thermo-oxidative aging. 50g of fresh emulsion sample from each experimental group was taken and poured into the viscometer sample cup. The temperature was adjusted to 25℃, and an LV-4 rotor was selected with a rotation speed of 100s. -1 After the rotor has been rotating stably for 30 seconds, record the initial viscosity η0. Take 80g of emulsion sample from each experimental group, inject it into a 100mL wide-mouth reagent bottle, seal it (wrap it with PTFE tape after tightening to prevent leakage), place it in a 50℃ constant temperature oven, and store it for 30 days (do not open the oven during this period to avoid temperature fluctuations). Test the viscosity η1 of the emulsion after storage according to the method in step 1, and calculate the viscosity change rate: viscosity change rate (%) = |η1-η0| / η0×100%. Test each sample in parallel 3 times and take the average value. (5) Viscosity test: Take 50 mL of emulsion sample, pour it into a sample cup, put it in a constant temperature water bath, adjust the temperature to 25℃, keep it warm for 10 min, measure the viscosity of the emulsion with a rotation viscometer, record the viscosity value, repeat the test 3 times for each sample, and take the average value. (6) Solid content test: Place a clean aluminum weighing dish in a 105℃ oven and dry for 2 hours. After taking it out, place it in a desiccator to cool for 30 minutes and weigh it. Record the weight as m0. Repeat the steps of drying for 1 hour, cooling and weighing until constant weight. Use a glass rod to take about 1.0000g of emulsion sample and spread it evenly in the constant weight weighing dish. Record the weight as m1. Place the weighing dish containing the sample in a 105℃ oven, open the lid and dry for 2 hours. Take out the weighing dish, close the lid tightly, place it in a desiccator to cool for 30 minutes and weigh it. Record the weight as m2. Repeat the steps of drying for 30 minutes, cooling and weighing until constant weight. Calculate the solid content (%): solid content = (m2-m0) / (m1-m0)×100%. Each sample is tested in parallel 3 times and the average value is taken.

[0043] The results are shown in Table 1 below.

[0044] Table 1. Results of physicochemical properties test of emulsion

[0045] As shown in Table 1, compared with Example 5, Comparative Example 1 lacked a toughening agent, and its average particle size increased from 175 mm to 212 mm, while the distribution span expanded from 1.6 to 2.3. This indicates that the toughening agent has good interfacial compatibility and can form molecular-level entanglements with the core layer 2-EHA and the shell layer MMA, inhibiting particle aggregation and ensuring the uniformity of emulsion particles. Comparative Example 1 had a lower Zeta potential than Example 5, but a higher centrifugal stratification rate and thermal storage viscosity change rate. This is because the reactive double bonds at both ends of the toughening agent can synergistically interact with the phosphate groups of the emulsifier, enhancing the electrostatic repulsion on the particle surface, thereby increasing the Zeta potential and significantly reducing the centrifugal stratification rate and thermal storage viscosity change rate. Furthermore, the flexible segments of the toughening agent can regulate the intermolecular forces within the emulsion, preventing excessive particle aggregation that could lead to increased viscosity and thus reducing viscosity, which is suitable for the requirements of soft ceramic coating processes. Comparative Example 2, without the addition of antibacterial flame retardants, showed that the emulsion properties were similar to those of Example 5, indicating that the antibacterial flame retardants had good compatibility with the emulsion system, no negative interference, and did not change the process adaptability of the emulsion.

[0046] II. Mechanical Property Testing The following performance tests were performed on the soft ceramics prepared in Example 6, Comparative Example 3, and Comparative Example 4: (1) Low temperature flexibility, refer to GB / T6742-2007, freeze at -20℃ for 2h, bend with a 50mm diameter cylinder and observe the crack; test the impact strength by falling ball impact method (1kg steel ball, dropped freely from a height of 1m). (2) Tensile properties, refer to GB / T528-2009, dumbbell-shaped specimen (gauge length 25mm), tensile rate 50mm / min, measure tensile strength and elongation at break; (3) Adhesion, refer to GB / T9286-2021, cross-cut test (1mm×1mm square), and the rating after the tape is peeled off (0 is the best and 5 is the worst).

[0047] The results are shown in Table 2 below.

[0048] Table 2 Mechanical Properties Test of Soft Porcelain

[0049] As shown in Table 2, the mechanical properties of Comparative Example 3, lacking a toughening agent, decreased significantly. The polyether segments in the toughening agent could still rotate freely at -20℃, providing molecular-level lubrication for the flexible ceramic and alleviating stress concentration at low temperatures. The polyester segments formed hydrogen bonds with the hydroxyl groups on the sand powder surface, enhancing interfacial bonding and thus improving impact strength. The reactive double bonds of the toughening agent copolymerized with the emulsion monomers to form a cross-linked network, limiting the low-temperature shrinkage of the molecular chains. Comparative Example 3, lacking this network, was prone to through-cracks during bending, while the optimized group maintained structural integrity. Furthermore, the block structure of the toughening agent reduced the interfacial tension between the emulsion and the sand powder, improving wettability and raising the adhesion from grade 2 to grade 0. Simultaneously, the cross-linked network enhanced stress transfer during tension, increasing elongation at break and meeting the deformation requirements of flexible ceramic construction. The mechanical properties of the flexible ceramic in Comparative Example 4 were comparable to those in Example 6, indicating that the absence of the antibacterial flame retardant had a minimal impact on its mechanical properties.

[0050] III. Functional Testing The following performance tests were performed on the soft ceramics prepared in Example 6, Comparative Example 3, and Comparative Example 4: (1) Antibacterial performance test: referring to GB / T21866-2008, Escherichia coli (ATCC25922) and Staphylococcus aureus (ATCC29213) were selected, and the bacterial concentration was 10. 6 CFU / mL, the sample was mixed with bacterial suspension at a ratio of 1:10, shaken at 30℃ for 24 h, and the sterilization rate was determined by plate counting. (2) Flame retardant performance test: Oxygen index (LOI) refers to GB / T2406.2-2009, sample size 100mm×10mm×5mm, oxygen index meter to measure the lowest oxygen concentration; Vertical burning: refers to UL94 standard, sample size 130mm×13mm×5mm, Bunsen burner flame (50W) for 10s, observe burning time and dripping situation; (3) Weather resistance test, referring to GB / T1865-2009, ultraviolet aging chamber (340nm ultraviolet lamp, irradiation intensity 0.71W / m). 2 The material was aged at 60℃ / 70%RH for 1000 hours, and the impact strength retention rate, color difference (ΔE), and gloss retention rate (60° angle) were measured after aging.

[0051] The results are shown in Table 3 below.

[0052] Table 3. Results of Functional Testing of Soft Porcelain

[0053] As can be seen from the data in Table 3, the antibacterial and flame-retardant properties of Comparative Example 4 decreased significantly compared to Example 6. The benzisothiazolinone ring (BIT) retained in the antibacterial flame retardant can penetrate bacterial cell membranes and react with protein sulfhydryl groups (-SH), inhibiting enzyme activity and achieving a sterilization rate of over 99.6%. Comparative Example 4, lacking the BIT structure, relied solely on physical adsorption by sand powder, resulting in a sterilization rate of less than 15% and no actual antibacterial effect. The nitrogen element in the antibacterial flame retardant decomposes at high temperatures to produce inert gases such as NH3 and N2, diluting the oxygen concentration and increasing the oxygen index. The phosphorus groups (P=O) form a phosphate ester coating, encapsulating the sand powder particles and inhibiting the volatilization of thermal decomposition products. Simultaneously, the nitrogen element promotes char formation, resulting in a dense char layer after combustion without dripping.

[0054] Comparative Example 3 showed a significant decrease in weather resistance. Lacking a toughening agent, Comparative Example 3's polyether polyester block structure provides a dual protection against UV aging. Firstly, the polyether segments (PEO) absorb some UV light, reducing direct damage to the emulsion molecular chains from ultraviolet radiation. Secondly, the cross-linking network formed by the toughening agent and the emulsion monomers inhibits the breakage and rearrangement of molecular chains during aging. In contrast, Comparative Example 3, lacking this cross-linking network, was prone to chemical bond breakage at the emulsion-powder interface under UV light, resulting in a rapid decrease in impact strength and failing to meet the mechanical stability requirements for long-term outdoor use. Furthermore, the lack of a toughening agent in Comparative Example 3 resulted in weak interfacial bonding between the emulsion and powder, leading to micro-cracks at the interface under high temperature and humidity conditions. Pigment migration with moisture caused localized fading and yellowing. In addition, the toughening agent improves the uniformity of emulsion film formation, creating a continuous and dense surface film that blocks the intrusion of moisture and oxygen. Simultaneously, its cross-linking network inhibits thermo-oxidative aging of the emulsion film at high temperatures. Comparative Example 3, lacking toughening agents, had a loose surface emulsion film structure, making it prone to thermal and oxidative degradation during aging. The volatilization of small molecules left pores, leading to surface gloss loss. In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0055] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed invention.

Claims

1. A large-particle-size, highly permeable emulsion specifically for flexible porcelain, characterized in that, The emulsion comprises: Seed phase: 40-45 parts deionized water, 1.2-1.5 parts ethyl methacrylate, 8-10 parts methyl methacrylate, 0.3-0.5 parts sodium bicarbonate; Nuclear emulsion phase: 30-35 parts deionized water, 35-40 parts isooctyl acrylate, 2-3 parts glycidyl methacrylate, 3-5 parts toughening agent, 0.8-1 part ethyl methacrylate, 0.3-0.5 parts OP-10 emulsifier; Hard-shell preemulsion phase: 45-50 parts deionized water, 25-30 parts methyl methacrylate, 7-8.4 parts styrene, 3-3.6 parts isobornyl methacrylate, 1.5-2.0 parts acrylic acid, 1.0-1.5 parts hydroxyethyl acrylate, 0.8-1.2 parts N-hydroxymethylacrylamide, 1.5-2.0 parts hydroxypropyl methacrylate, 1.0-1.2 parts ethyl methacrylate, and 0.5-0.8 parts allyl polyoxyethylene ether; Initiation system: 10-20 parts deionized water, 0.6-0.8 parts ammonium persulfate, 0.15-0.25 parts sodium bisulfite, and 0.15-0.25 parts tert-butyl hydroperoxide; Post-treatment additives: 0.3-0.5 parts antibacterial flame retardant, 0.2-0.3 parts silicone defoamer, and 3-5 parts ammonia. The toughening agent is a polyether-polyester block copolymer, which adopts a polyethylene glycol monomethyl ether-polybutylene adipate block structure, with hydroxyethyl methacrylate connected to both ends by isocyanate. The antibacterial flame retardant is a phosphorus and nitrogen-containing benzisothiazolinone derivative, which is obtained by introducing an active chloromethyl group through chloromethylation of 1,2-benzisothiazol-3-one, followed by nucleophilic substitution reaction of the chloromethyl group with diethyl phosphite.

2. The large-particle-size, high-permeability emulsion for soft porcelain according to claim 1, characterized in that, The preparation method of the toughening agent includes the following steps: (1) Polyethylene glycol monomethyl ether and polybutylene adipate were added to the reactor, heated to 80~85℃, vacuum dehydrated for 0.5~1.5h, cooled to 60℃, hexamethylene diisocyanate and dibutyltin dilaurate were added, and the temperature was slowly raised to 80~85℃ under nitrogen protection and kept at the temperature for 2~3h to obtain a block prepolymer containing -NCO at both ends; (2) Cool the above block prepolymer to 50~55℃, add hydroxyethyl methacrylate and hydroquinone, stir evenly, then heat to 70~75℃ and keep the reaction at this temperature for 1.5~2.5h to obtain the crude product of block copolymer; (3) Cool the crude block copolymer product to 40°C, add 30% of the crude product mass of ethyl acetate to dissolve it, then pour it into 5 times the volume of deionized water, stir for 20-40 min, let it stand and separate into layers, discard the aqueous phase, wash the organic phase with deionized water 3-5 times, and then remove ethyl acetate under vacuum to obtain the toughening agent.

3. The large-particle-size, high-permeability emulsion for soft porcelain according to claim 2, characterized in that, The mass ratio of polyethylene glycol monomethyl ether, polybutylene adipate, and hexamethylene diisocyanate is 8:7:2, and the amount of dibutyltin dilaurate is 1% to 1.5% of the mass of hexamethylene diisocyanate.

4. The large-particle-size, high-permeability emulsion for soft porcelain according to claim 2, characterized in that, The mass ratio of hydroxyethyl methacrylate to hexamethylene diisocyanate is 3:5, and the amount of hydroquinone used is 0.5% to 1% of the mass of hydroxyethyl methacrylate.

5. The large-particle-size, high-permeability emulsion for soft porcelain according to claim 1, characterized in that, The preparation method of the antibacterial flame retardant includes the following steps: A. Add 1,2-benzisothiazol-3-one to concentrated hydrochloric acid, place in an ice bath at 0-5°C, slowly add formaldehyde aqueous solution, remove the ice bath after the addition is complete, stir the reaction at room temperature for 6-8 hours, after the reaction is complete, slowly pour the reaction solution into ice water to precipitate solid product, filter and wash the solid thoroughly with cold water, and vacuum dry to obtain intermediate A. B. Add intermediate A to anhydrous acetonitrile, and under nitrogen protection and ice-water bath cooling, slowly add a suspension made of potassium carbonate and anhydrous acetonitrile, then slowly add diethyl phosphite. After the addition is complete, raise the temperature to 70-80°C and reflux for 8-12 hours. After the reaction is complete, cool to room temperature, filter to remove inorganic salts, concentrate the filtrate under reduced pressure, and then purify by column chromatography to obtain the antibacterial flame retardant.

6. The large-particle-size, high-permeability emulsion for soft porcelain according to claim 5, characterized in that, The mass ratio of 1,2-benzisothiazol-3-one to formaldehyde is 5:

1.

7. The large-particle-size, high-permeability emulsion for soft porcelain according to claim 5, characterized in that, The mass ratio of intermediate A, potassium carbonate, and diethyl phosphite is 5:4:

4.

8. A method for preparing a large-particle-size, highly permeable emulsion for soft porcelain as described in any one of claims 1 to 7, characterized in that, Includes the following steps: S1. Seed phase preparation: Add deionized water to the reaction vessel, heat to 80℃, purge with nitrogen for protection, start stirring, and add ethyl methacrylate, methyl methacrylate and sodium bicarbonate in sequence. After the addition is completed, keep warm for 20-40 min. S2. Preparation of core emulsion phase: Deionized water, isooctyl acrylate, glycidyl methacrylate, toughening agent, ethyl phosphate methacrylate, and OP-10 emulsifier are mixed and pre-emulsified to obtain core emulsion phase; S3. Preparation of hard-shell preemulsion phase: Deionized water, methyl methacrylate, styrene, isobornyl methacrylate, acrylic acid, hydroxyethyl acrylate, N-hydroxymethylacrylamide, hydroxypropyl methacrylate, ethyl phosphate methacrylate, and allyl polyoxyethylene ether are mixed and preemulsified to obtain a hard-shell preemulsion phase. S4. Deionized water, ammonium persulfate, sodium bisulfite, and tert-butyl hydroperoxide were mixed to obtain an initiation system. The initiation system was then added dropwise to the reactor simultaneously with the core emulsion phase and the hard shell pre-emulsion phase at 75°C. After all the initiation system was added, the reactor was kept at 70°C for 0.5 to 1.5 hours to mature. S5. Cool to room temperature, add antibacterial flame retardant and organosilicon defoamer and stir evenly, adjust pH to 8-9 with ammonia water, filter and discharge to obtain the large particle size high air permeability soft porcelain special emulsion.

9. The method for preparing the large-particle-size, highly permeable emulsion for soft porcelain according to claim 8, characterized in that, In step S4, half of the initiation system and the core emulsion phase are first added dropwise to the reactor simultaneously. After the core emulsion phase is added, the other half of the initiation system and the hard-shell pre-emulsion phase are added dropwise to the reactor simultaneously.

10. The application of a large-particle-size, highly permeable emulsion for soft porcelain as described in any one of claims 1 to 7, characterized in that, The large-particle-size, high-permeability flexible porcelain emulsion is mixed with sand powder in a 1:3 ratio, and after molding, it is dried in an oven at 90~110℃ to obtain large-particle-size, high-permeability flexible porcelain. The finished product is free of bubbles and skin, demolds smoothly, has a smooth surface, good toughness, good low-temperature toughness, and antibacterial and flame-retardant effects, making it suitable for flexible porcelain projects with high requirements for safety and environmental adaptability.

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