Environment-friendly long-acting mildew-proof silicone sealant and preparation method thereof

Abstract

The application discloses an environment-friendly long-acting mildew-proof silicone sealant and a preparation method thereof. The environment-friendly long-acting mildew-proof silicone sealant comprises the following raw material components in parts by mass: 100 parts of alpha, omega dihydroxypolydimethylsiloxane, 5-15 parts of CDs-SiO2, 3-50 parts of dimethyl silicone oil, 70-160 parts of inorganic filler, 3-7 parts of crosslinking agent, 1-3 parts of coupling agent and 3-6 parts of catalyst. The CDs-SiO2 is made of cyclodextrin inclusion compound, silane coupling agent and porous silicon dioxide, the porous silicon dioxide is obtained by reacting tetrabutyl silicate in a mixed medium of alcohol and water under the action of an amine catalyst and a pore former; and the cyclodextrin inclusion compound is made of monochlorotriazine-cyclodextrin and natural mildew-proof agent. The silicone sealant has excellent long-acting mildew-proof effect and mechanical properties.

Description

Technical Field

[0001] This invention belongs to the field of sealant technology, and in particular relates to an environmentally friendly, long-lasting, mildew-resistant silicone sealant and its preparation method. Background Technology

[0002] In the home decoration industry, when silicone sealant is used in bathrooms, kitchens, and other places, it is easily attacked by microorganisms due to the long-term exposure to humid and hot environments, which can lead to mold, discoloration, environmental pollution, and loss of waterproof and sealing functions.

[0003] To overcome the aforementioned problems, existing technologies often inhibit microbial invasion by directly adding antifungal agents. Commonly used antifungal agents include halides, quaternary ammonium salts, nitrogen-containing heterocyclic compounds, and isothiazolinides. For example, patent CN115785897A proposes adding quaternary ammonium salt antibacterial and antifungal agents to neutral silicone sealant to prepare an antibacterial and antifungal neutral silicone sealant. Because quaternary ammonium salt antibacterial and antifungal agents carry a positive charge, they can contact the negative charge on the bacterial film surface to kill bacteria. However, the above-mentioned antifungal agents have disadvantages such as toxicity, environmental harm, poor stability, and short-lasting effectiveness. With the global pursuit of green and environmentally friendly building materials, the production of safe, environmentally friendly, and long-lasting antifungal silicone sealants has become an inevitable trend. Summary of the Invention

[0004] Based on this, the purpose of the present invention is to provide an environmentally friendly, long-lasting, mildew-resistant silicone sealant.

[0005] To achieve the above objectives, the present invention includes the following technical solutions.

[0006] An environmentally friendly, long-lasting, mildew-resistant silicone sealant, comprising the following raw material components in parts by weight:

[0007]

[0008]

[0009] In some embodiments, the environmentally friendly, long-lasting, mildew-resistant silicone sealant comprises the following raw material components in parts by weight:

[0010] 100 parts of α,ω-dihydroxypolydimethylsiloxane

[0011]

[0012] In some embodiments, the environmentally friendly, long-lasting, mildew-resistant silicone sealant comprises the following raw material components in parts by weight:

[0013]

[0014] In some embodiments, the silane coupling agent is 3-aminopropyltriethoxysilane.

[0015] In some embodiments, the porogen is 1,3,5-trimethylbenzene.

[0016] In some embodiments, the amine catalyst is a C1-C16 alkylamine, preferably a C10-C14 alkylamine, and more preferably a dodecylamine.

[0017] In some embodiments, the cyclodextrin is one or a combination of two or more of α-cyclodextrin, β-cyclodextrin, and γ-cyclodextrin.

[0018] In some embodiments, the antifungal agent is one or more combinations of catechin, eugenol, vanillin and cinnamic acid, preferably cinnamic acid.

[0019] In some embodiments, the mass ratio of the cyclodextrin inclusion complex to the silane coupling agent is 1:0.2-1, preferably 1:0.4-0.6.

[0020] In some embodiments, the mass ratio of the cyclodextrin inclusion complex to tetrabutyl silicate is 1:1-3, preferably 1:2.2-2.8.

[0021] In some embodiments, the mass ratio of tetrabutyl silicate to amine catalyst is 1:0.1-0.3, preferably 1:0.17-0.22.

[0022] In some embodiments, the mass ratio of tetrabutyl silicate to porogen is 1:0.05-0.2, preferably 1:0.07-0.11.

[0023] In some embodiments, the mass ratio of the monochlorotriazine-cyclodextrin to the antifungal agent is 1-4.5:1, preferably 1.5-2.5:1.

[0024] In some embodiments, the preparation method of the cyclodextrin inclusion complex includes the following steps: dispersing monochlorotriazine-cyclodextrin in water at 50℃-90℃, and when cooled to 35℃-45℃, adding an alcoholic solution of a fungicide dropwise under stirring, stirring for 1h-6h, and then crystallizing and precipitating to obtain the cyclodextrin inclusion complex.

[0025] In some embodiments, the method for preparing CDs-SiO2 includes the following steps:

[0026] (1) Stir the cyclodextrin inclusion complex and the silane coupling agent in water until homogeneous to obtain a mixture;

[0027] (2) Add the mixture to an ethanol aqueous solution containing an amine catalyst and stir until homogeneous. Add tetrabutyl silicate and stir until homogeneous. Then add a pore-forming agent and stir at 20℃-30℃ for 6h-24h to obtain the CDs-SiO2.

[0028] In some embodiments, the volume ratio of ethanol to water in the aqueous ethanol solution is 1:3-10.

[0029] In some embodiments, the α,ω dihydroxy polydimethylsiloxane has a viscosity of 1 Pa·s-300 Pa·s at 25°C, preferably 10 Pa·s-100 Pa·s.

[0030] In some embodiments, the dimethyl silicone oil has a viscosity of 0.1 Pa·s-1 Pa·s at 25°C, preferably 0.2 Pa·s-0.5 Pa·s.

[0031] In some embodiments, the inorganic filler is at least one of nano-activated calcium carbonate, heavy calcium carbonate, silica powder, and diatomaceous earth, preferably nano-activated calcium carbonate.

[0032] In some embodiments, the crosslinking agent is at least one selected from methyltrimethoxysilane, propyltrimethoxysilane, octyltrimethoxysilane, and phenyltrimethoxysilane.

[0033] In some embodiments, the coupling agent is at least one selected from γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane, γ-glycidyl etheroxypropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, and 3-isocyanate-propyltrimethoxysilane.

[0034] In some embodiments, the catalyst is a titanate catalyst; preferably, the catalyst is selected from at least one of tetraisopropyl titanate, tetrabutyl titanate, diisopropyl di(ethyl acetoacetate) titanate, dibutoxybis(ethyl acetoacetate) titanate, and di(ethyl acetoacetate) titanate.

[0035] A fourth aspect of the present invention is to provide a method for preparing an environmentally friendly, long-lasting, mildew-resistant silicone sealant, comprising the following steps:

[0036] (1) α,ω dihydroxy polydimethylsiloxane, CDs-SiO2, dimethyl silicone oil and inorganic filler were dehydrated and blended for 60 min to 120 min at a temperature of 90℃~120℃ and a vacuum degree of -0.08MPa~-0.1MPa, and the base material was obtained after cooling.

[0037] (2) The base material is put into a mixer, and the crosslinking agent, coupling agent and catalyst are added. The mixture is mixed and reacted for 50 min to 120 min under the conditions of vacuum degree of -0.08 MPa to -0.1 MPa and stirring speed of 10 Hz to 20 Hz to obtain the environmentally friendly long-lasting anti-mildew silicone sealant.

[0038] The purpose of this invention is to address the shortcomings of existing technologies by providing an environmentally friendly, long-lasting, mildew-resistant silicone sealant. Firstly, this invention uses a natural mildew inhibitor to replace traditional mildew inhibitors, overcoming their toxicity and environmental harmfulness. However, natural mildew inhibitors cannot achieve a long-lasting mildew-resistant effect. Therefore, to extend the mildew-resistant effect, this invention introduces cyclodextrin, utilizing its inclusion complex to achieve a slow-release of the natural mildew inhibitor. However, during the research process, it was found that the cyclodextrin inclusion complex has poor compatibility with the silicone sealant, resulting in uneven dispersion within the sealant and consequently a decrease in the mechanical properties of the silicone sealant. To further address this issue, this invention introduces a cyclodextrin inclusion complex into the porous silica channels, resulting in a cyclodextrin inclusion complex / porous silica composite, abbreviated as CDs-SiO2. This composite promotes the dispersibility of the cyclodextrin inclusion complex in silicone sealant, thereby effectively improving the mechanical properties of the silicone sealant. Simultaneously, the introduction of porous silica and cyclodextrin achieves a dual slow-release of the natural antifungal agent, with both having a synergistic effect, further extending the duration of action of the natural antifungal agent. Therefore, the environmentally friendly, long-lasting antifungal silicone sealant of this invention has the following beneficial effects:

[0039] This invention encapsulates a natural antifungal agent with cyclodextrin to form a cyclodextrin inclusion complex, and then loads the cyclodextrin inclusion complex into the pores of porous silica to prepare a cyclodextrin inclusion complex / porous silica composite material. When this composite material is added to silicone sealant, it exhibits good compatibility with the sealant and can be dispersed relatively uniformly within the sealant, effectively improving the mechanical properties of the silicone sealant. Simultaneously, the antifungal agent, through the dual slow-release effect of porous silica and cyclodextrin, effectively prolongs the duration of action of the natural antifungal agent. Combined with other raw material components such as dimethyl silicone oil, the prepared silicone sealant possesses both excellent long-lasting antifungal effect and superior mechanical properties.

[0040] In addition, the present invention uses a natural anti-mildew agent to overcome the shortcomings of traditional anti-mildew agents, which are toxic and harmful to the environment and human body. The CDs-SiO2 of the present invention is environmentally friendly and non-toxic, and its use in sealants can reduce environmental harm. Detailed Implementation

[0041] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments are merely illustrative of the present invention and should not be construed as limiting the invention.

[0042] Unless otherwise defined, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the invention.

[0043] Example 1

[0044] A method for preparing a cyclodextrin inclusion complex / porous silica composite (CDs-SiO2) includes the following steps:

[0045] (1) Preparation of cyclodextrin inclusion complex: 9 g of monochlorotriazine-β-cyclodextrin was dispersed in 100 ml of water at 60 °C to obtain a cyclodextrin solution; 5 g of cinnamic acid was dissolved in 50 ml of anhydrous ethanol to obtain a cinnamic acid solution. When the cyclodextrin solution was cooled to 40 °C, the cinnamic acid solution was added dropwise to the cyclodextrin solution under stirring. After stirring at 40 °C for 6 h, the resulting reaction mixture was cooled, crystallized and precipitated at 4 °C, filtered, and the cinnamic acid on the surface was washed away with 30% (v / v) ethanol solution. The mixture was dried, crushed and passed through a 100-mesh sieve to obtain the cyclodextrin inclusion complex.

[0046] (2) Preparation of CDs-SiO2: 10 g of the obtained cyclodextrin inclusion complex and 5 g of 3-aminopropyltriethoxysilane were stirred in 50 ml of water for 30 min. The resulting mixture was then added to 200 ml of an ethanol / water solution containing 5 g of dodecylamine (ethanol to water volume ratio 1:9) and stirred until homogeneous. 25 g of tetrabutyl silicate (TEOS) was added and stirred until homogeneous. 2 g of porogen 1,3,5-trimethylbenzene was added, and the mixture was stirred at 25 °C for 10 h. The mixture was filtered, washed with anhydrous ethanol, dried, and crushed to obtain the product, denoted as CDs-SiO2-1.

[0047] Example 2

[0048] A method for preparing a cyclodextrin inclusion complex / porous silica composite (CDs-SiO2) includes the following steps:

[0049] (1) Preparation of cyclodextrin inclusion complex: 7g of monochlorotriazine-β-cyclodextrin was dispersed in 60ml of water at 80℃ to obtain a cyclodextrin solution; 3g of cinnamic acid was dissolved in 30ml of ethanol to obtain a cinnamic acid solution. When the cyclodextrin solution was cooled to 40℃, the cinnamic acid solution was added dropwise to the cyclodextrin solution under stirring. After stirring at 40℃ for 5h, the resulting reaction mixture was cooled, crystallized and precipitated at 4℃. After filtration, the cinnamic acid on the surface was washed away with 30% (v / v) ethanol solution, dried, crushed and passed through a 100-mesh sieve to obtain the cyclodextrin inclusion complex.

[0050] (2) Preparation of CDs-SiO2: 8 g of the obtained cyclodextrin inclusion complex and 4 g of 3-aminopropyltriethoxysilane were stirred in 40 ml of water for 30 min. The resulting mixture was then added to 160 ml of an ethanol / water solution containing 3.5 g of dodecylamine (ethanol to water volume ratio 1:7) and stirred until homogeneous. 20 g of TEOS was added and stirred until homogeneous. 2 g of porogen 1,3,5-trimethylbenzene was added, and the mixture was stirred at 30 °C for 8 h. The mixture was filtered, washed with anhydrous ethanol, dried, and crushed to obtain the product, denoted as CDs-SiO2-2.

[0051] Example 3

[0052] A method for preparing a cyclodextrin inclusion complex / porous silica composite (CDs-SiO2) includes the following steps:

[0053] (1) Preparation of cyclodextrin inclusion complex: 4 g of monochlorotriazine-β-cyclodextrin was dispersed in 20 ml of water at 50 °C to obtain a cyclodextrin solution; 1 g of cinnamic acid was dissolved in 30 ml of ethanol to obtain a cinnamic acid solution. When the cyclodextrin solution was cooled to 40 °C, the cinnamic acid solution was added dropwise to the cyclodextrin solution under stirring. After stirring at 40 °C for 3 h, the resulting reaction mixture was cooled, crystallized and precipitated at 4 °C. After filtration, the cinnamic acid on the surface was washed away with 30% (v / v) ethanol solution, dried, crushed and passed through a 100-mesh sieve to obtain the cyclodextrin inclusion complex.

[0054] (2) Preparation of CDs-SiO2: 3g of the obtained cyclodextrin inclusion complex and 1g of 3-aminopropyltriethoxysilane were stirred in 20ml of water for 10min. The resulting mixture was then added to 100ml of an ethanol / water solution containing 0.8g of dodecylamine (ethanol to water volume ratio 3:9) and stirred until homogeneous. 5g of TEOS was added and stirred until homogeneous. 0.7g of porogen 1,3,5-trimethylbenzene was added, and the mixture was stirred at 20℃ for 20h. The mixture was filtered, washed, dried, and crushed to obtain the product, denoted as CDs-SiO2-3.

[0055] Example 4

[0056] An environmentally friendly, long-lasting, mildew-resistant silicone sealant is prepared from the following components in parts by weight:

[0057]

[0058] The α,ω dihydroxy polydimethylsiloxane has a viscosity of 50 Pa·s at 25°C; the CDs-SiO2 is CDs-SiO2-1 prepared in Example 1; the dimethyl silicone oil has a viscosity of 0.3 Pa·s at 25°C; the inorganic filler is nano-activated calcium carbonate; the crosslinking agent is methyltrimethoxysilane; the coupling agent is γ-aminopropyltriethoxysilane; and the catalyst is diisopropyl di(ethyl acetoacetate) titanate.

[0059] The preparation method of the environmentally friendly, long-lasting, mildew-resistant silicone sealant includes the following steps:

[0060] (1) α,ω dihydroxy polydimethylsiloxane, CDs-SiO2-1, dimethyl silicone oil and nano-active calcium carbonate were dehydrated and blended for 90 minutes at a temperature of 110℃ and a vacuum degree of -0.095MPa, and the base material was obtained after cooling.

[0061] (2) The base material is put into a planetary mixer, and methyltrimethoxysilane, γ-aminopropyltriethoxysilane and diisobutyl bis(acetoacetate)titanate are added. The mixture is stirred for 90 minutes under a vacuum of -0.095MPa and a stirring speed of 15Hz to obtain an environmentally friendly, long-lasting, mildew-proof silicone sealant.

[0062] Example 5

[0063] An environmentally friendly, long-lasting, mildew-resistant silicone sealant is prepared from the following components in parts by weight:

[0064]

[0065] The α,ω dihydroxy polydimethylsiloxane has a viscosity of 50 Pa·s at 25°C; the CDs-SiO2 is the CDs-SiO2-2 prepared in Example 2; the dimethyl silicone oil has a viscosity of 0.3 Pa·s at 25°C; the inorganic filler is nano-activated calcium carbonate; the crosslinking agent is methyltrimethoxysilane; the coupling agent is γ-aminopropyltriethoxysilane; and the catalyst is diisopropyl di(ethyl acetoacetate) titanate.

[0066] The preparation method of the environmentally friendly, long-lasting, mildew-resistant silicone sealant includes the following steps:

[0067] (1) α,ω dihydroxy polydimethylsiloxane, CDs-SiO2-2, dimethyl silicone oil and nano-active calcium carbonate were dehydrated and blended for 90 minutes at a temperature of 110℃ and a vacuum degree of -0.095MPa, and the base material was obtained after cooling.

[0068] (2) The base material is put into a planetary mixer, and methyltrimethoxysilane, γ-aminopropyltriethoxysilane and diisobutyl bis(acetoacetate)titanate are added. The mixture is stirred for 90 minutes under a vacuum of -0.095MPa and a stirring speed of 15Hz to obtain an environmentally friendly, long-lasting, mildew-proof silicone sealant.

[0069] Example 6

[0070] An environmentally friendly, long-lasting, mildew-resistant silicone sealant is prepared from the following components in parts by weight:

[0071]

[0072] The α,ω dihydroxy polydimethylsiloxane has a viscosity of 50 Pa·s at 25°C; the CDs-SiO2 is the CDs-SiO2-3 prepared in Example 3; the dimethyl silicone oil has a viscosity of 0.3 Pa·s at 25°C; the inorganic filler is nano-activated calcium carbonate; the crosslinking agent is methyltrimethoxysilane; the coupling agent is γ-aminopropyltriethoxysilane; and the catalyst is diisopropyl di(ethyl acetoacetate) titanate.

[0073] The preparation method of the environmentally friendly, long-lasting, mildew-resistant silicone sealant includes the following steps:

[0074] (1) α,ω dihydroxy polydimethylsiloxane, CDs-SiO2-3, dimethyl silicone oil and nano-active calcium carbonate were dehydrated and blended for 90 minutes at a temperature of 110℃ and a vacuum degree of -0.095MPa, and the base material was obtained after cooling.

[0075] (2) The base material is put into a planetary mixer, and methyltrimethoxysilane, γ-aminopropyltriethoxysilane and diisobutyl bis(acetoacetate)titanate are added. The mixture is stirred for 90 minutes under a vacuum of -0.095MPa and a stirring speed of 15Hz to obtain an environmentally friendly, long-lasting, mildew-proof silicone sealant.

[0076] Example 7

[0077] An environmentally friendly, long-lasting, mildew-resistant silicone sealant is prepared from the following components in parts by weight:

[0078]

[0079]

[0080] The α,ω dihydroxy polydimethylsiloxane has a viscosity of 100 Pa·s at 25°C; the CDs-SiO2 is CDs-SiO2-1 prepared in Example 1; the dimethyl silicone oil has a viscosity of 0.2 Pa·s at 25°C; the inorganic filler is heavy calcium carbonate; the crosslinking agent is propyltrimethoxysilane; the coupling agent is N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane; and the catalyst is diisopropyl di(ethyl acetoacetate) titanate.

[0081] The preparation method of the environmentally friendly, long-lasting, mildew-resistant silicone sealant includes the following steps:

[0082] (1) α,ω dihydroxy polydimethylsiloxane, CDs-SiO2-1, dimethyl silicone oil and heavy calcium carbonate were dehydrated and blended for 60 minutes at a temperature of 120℃ and a vacuum degree of 0.1MPa, and the base material was obtained after cooling.

[0083] (2) The base material is put into a planetary mixer, and propyltrimethoxysilane, N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane and diisopropyl di(ethyl acetoacetate) titanate are added. The mixture is stirred for 120 min under a vacuum of -0.1 MPa and a stirring speed of 10 Hz to obtain an environmentally friendly, long-lasting, mildew-proof silicone sealant.

[0084] Example 8

[0085] An environmentally friendly, long-lasting, mildew-resistant silicone sealant is prepared from the following components in parts by weight:

[0086]

[0087] The α,ω dihydroxy polydimethylsiloxane has a viscosity of 10 Pa·s at 25°C; the CDs-SiO2 is CDs-SiO2-1 prepared in Example 1; the dimethyl silicone oil has a viscosity of 0.5 Pa·s at 25°C; the inorganic filler is silica powder; the crosslinking agent is octyltrimethoxysilane; the coupling agent is γ-glycidyl ether propyltrimethoxysilane; and the catalyst is dibutoxybis(ethyl acetoacetate) titanate.

[0088] The preparation method of environmentally friendly, long-lasting, mildew-resistant silicone sealant includes the following steps:

[0089] (1) α,ω dihydroxy polydimethylsiloxane, CDs-SiO2-1, dimethyl silicone oil and silicon micro powder were dehydrated and blended for 120 minutes at a temperature of 90℃ and a vacuum degree of 0.08MPa, and the base material was obtained after cooling.

[0090] (2) The base material is put into a planetary mixer, and octyltrimethoxysilane, γ-glycidyl ether propyltrimethoxysilane and dibutoxybis(ethyl acetoacetate) titanate are added. The mixture is stirred for 50 minutes under a vacuum of -0.08 MPa and a stirring speed of 20 Hz to obtain an environmentally friendly, long-lasting, mildew-proof silicone sealant.

[0091] Example 9

[0092] The silicone sealant in this embodiment differs from that in Example 4 in that the antifungal agent cinnamic acid in CDs-SiO2 in Example 4 is replaced with an equal amount of eugenol.

[0093] Its preparation method is the same as that of the environmentally friendly, long-lasting, mildew-resistant silicone sealant in Example 4.

[0094] Example 10

[0095] The silicone sealant in this embodiment differs from that in Example 4 in that the antifungal agent cinnamic acid in CDs-SiO2 in Example 4 is replaced with an equal amount of vanillin.

[0096] Its preparation method is the same as that of the environmentally friendly, long-lasting, mildew-resistant silicone sealant in Example 4.

[0097] Example 11

[0098] The silicone sealant in this embodiment differs from that in Example 4 in that the antifungal agent cinnamic acid in CDs-SiO2 in Example 4 is replaced with an equal amount of catechin.

[0099] Its preparation method is the same as that of the environmentally friendly, long-lasting, mildew-resistant silicone sealant in Example 4.

[0100] Comparative Example 1

[0101] The silicone sealant in this comparative example differs from that in Example 4 in that CDs-SiO2 in Example 4 is replaced with an equal amount of cinnamic acid.

[0102] Its preparation method is the same as that of the environmentally friendly, long-lasting, mildew-resistant silicone sealant in Example 4.

[0103] Comparative Example 2

[0104] The silicone sealant in this comparative example differs from that in Example 4 in that CDs-SiO2 in Example 4 is replaced with an equal amount of cyclodextrin inclusion complex; the preparation method of the cyclodextrin inclusion complex is the same as that in Example 1.

[0105] The preparation method of the silicone sealant is the same as that of the environmentally friendly, long-lasting, mildew-proof silicone sealant in Example 4.

[0106] Comparative Example 3

[0107] The silicone sealant in this comparative example differs from that in Example 4 in that CDs-SiO2 is not added to the silicone sealant in this comparative example.

[0108] Its preparation method is the same as that of the environmentally friendly, long-lasting, mildew-resistant silicone sealant in Example 4.

[0109] Comparative Example 4

[0110] The silicone sealant in this comparative example differs from that in Example 4 in that: the silicone sealant in this comparative example does not contain CDs-SiO2, but contains an equal amount of cinnamic acid-SiO2.

[0111] Its preparation method is the same as that of the environmentally friendly, long-lasting, mildew-resistant silicone sealant in Example 4.

[0112] The preparation of cinnamic acid-SiO2 is as follows: 10g of cinnamic acid and 5g of 3-aminopropyltriethoxysilane were stirred in 50ml of water for 30min. The resulting mixture was then added to 200ml of an ethanol / water solution containing 5g of dodecylamine (ethanol to water volume ratio 1:9), and stirred until homogeneous. 25g of tetrabutyl silicate (TEOS) was added, and stirred until homogeneous. 2g of porogen 1,3,5-trimethylbenzene was added, and the mixture was stirred at 25℃ for 10h. The mixture was filtered, washed with anhydrous ethanol, dried, and crushed to obtain the product, denoted as cinnamic acid-SiO2.

[0113] Performance testing

[0114] 1. Tensile bond strength and elongation at break tests

[0115] The silicone sealants prepared in Examples 4-11 and Comparative Examples 1-4 were tested for tensile bond strength and elongation at break according to GB / T13477 "Building Sealing Materials - Part 8: Determination of Tensile Adhesion". The results are shown in Table 1.

[0116] 2. Anti-mildew performance test

[0117] The silicone sealants prepared in Examples 4-11 and Comparative Examples 1-4 were subjected to anti-mold tests according to GB / T 1741 "Determination of Anti-mold Resistance of Coatings".

[0118] Among them, after 28 days of culture using the petri dish method, if mold is clearly visible to the naked eye on the sample surface and the mold coverage area is greater than 60%, it is classified as level 4; if mold is clearly visible to the naked eye on the sample surface and the mold coverage area is 30% to 60%, it is classified as level 3; if mold is clearly visible to the naked eye on the sample surface and the mold coverage area is 10% to 30%, it is classified as level 2; if mold is not visible to the naked eye or is difficult to see, but is clearly visible under a magnifying glass, it is classified as level 1; if no obvious mold is visible on the sample surface at approximately 50x magnification, it is classified as level 0.

[0119] Based on level 0, the incubation time was extended further, and mold growth was observed. A 28-day cycle was used as the basis. If the level remained at level 0 after one more cycle, it was designated as level 2 (double level 0); if it remained at level 0 after two more cycles, it was designated as level 3 (triple level 0), and so on. A higher level 0 multiple indicates a longer duration of mold prevention and a better mold-preventing effect. The experimental results are shown in Table 1.

[0120] Table 1

[0121]

[0122]

[0123] As shown in Table 1, the silicone sealants of Examples 4-7 and Examples 9-11 all have a mildew resistance rating of 3 times or higher than Grade 0, demonstrating excellent mildew resistance. Furthermore, their tensile bond strength is above 1 MPa, and their elongation at break is above 280%, indicating good mechanical properties. Among these, the products of Examples 4 and 5 have suitable composition, achieving a mildew resistance rating of 5 times Grade 0, meaning that even after approximately 5 months of cultivation, there is still no significant mildew growth, indicating an extremely long-lasting mildew-resistant effect. Examples 7 and 8 have lower CDs-SiO2 content than Example 4, resulting in poorer mechanical and mildew resistance. Additionally, the inorganic fillers used in Examples 7 and 8 are heavy calcium carbonate and silica powder, respectively, whose reinforcing effect is somewhat inferior to that of nano-activated calcium carbonate, thus leading to significantly lower mechanical properties compared to Example 4. Furthermore, an unexpected finding from the comparison between Examples 4 and Examples 9-10 is that cinnamic acid, as the natural mildew inhibitor, provides the best mildew resistance.

[0124] Comparing Example 4 with Comparative Example 3, it can be seen that adding CDs-SiO2 can effectively improve the anti-mold level, and its mechanical properties are also improved. Comparing Example 4 with Comparative Examples 1 and 2, it can be seen that the addition of CDs-SiO2, compared with the addition of a single natural anti-mold agent and cyclodextrin inclusion complex, gives the product a longer-lasting anti-mold performance; although the cyclodextrin inclusion complex improves the anti-mold duration to a certain extent compared with a single natural anti-mold agent, its mechanical properties are significantly reduced. Comparing Example 4 with Comparative Examples 2 and 4, it can be seen that the cyclodextrin inclusion complex has a better sustained-release effect on the natural anti-mold agent than silica, and the silica in CDs-SiO2 and cyclodextrin have a synergistic sustained-release effect.

[0125] The above data demonstrates that the present invention achieves dual sustained release of natural antifungal agents in silicone sealant through the introduction of porous silica and cyclodextrin. The two have a synergistic sustained release effect, effectively prolonging the action time of natural antifungal agents, while improving the dispersibility of CDs-SiO2 in silicone sealant, and effectively improving the mechanical properties of silicone sealant.

[0126] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A long-lasting, mildew-resistant silicone sealant, characterized in that, The raw material components include the following parts by weight: 100 parts of α,ω-dihydroxypolydimethylsiloxane CDs-SiO2 5-15 parts, 3-50 parts of dimethyl silicone oil 70-160 parts of inorganic filler 3-7 parts of crosslinking agent 1-3 parts of coupling agent, 3-6 parts of catalyst, The CDs-SiO2 is made of cyclodextrin inclusion complex, silane coupling agent and porous silica, which is obtained by reacting tetrabutyl silicate in a mixed medium of alcohol and water under the action of amine catalyst and pore-forming agent. The cyclodextrin inclusion complex was made from monochlorotriazine-cyclodextrin and a fungicide; The preparation method of CDs-SiO2 includes the following steps: (1) The cyclodextrin inclusion complex and the silane coupling agent were stirred evenly in water to obtain a mixture; (2) Add the mixture to an ethanol aqueous solution containing an amine catalyst and stir until uniform. Add tetrabutyl silicate and stir until uniform. Then add a pore-forming agent and stir at 20℃-30℃ for 6h-24h to obtain the CDs-SiO2. The mass ratio of the cyclodextrin inclusion complex to the silane coupling agent is 1:0.2-1; The mass ratio of the cyclodextrin inclusion complex to tetrabutyl silicate is 1:1-3; The mass ratio of tetrabutyl silicate to porogen is 1:0.05-0.2; The mass ratio of the monochlorotriazine-cyclodextrin to the antifungal agent is 1-4.5:

1.

2. The long-lasting anti-mildew silicone sealant according to claim 1, characterized in that, The raw material components include the following parts by weight: 100 parts of α,ω-dihydroxypolydimethylsiloxane CDs-SiO2 8-15 parts, 25-50 parts of dimethyl silicone oil 90-160 parts of inorganic filler 3-7 parts of crosslinking agent 1-3 parts of coupling agent, Catalyst 3-6 parts.

3. The long-lasting anti-mildew silicone sealant according to claim 1, characterized in that, The raw material components include the following parts by weight: 100 parts of α,ω-dihydroxypolydimethylsiloxane CDs-SiO2 12-14 parts, 28-32 parts of dimethyl silicone oil Inorganic filler 115-125 parts, 4-6 parts of crosslinking agent 1-2 parts of coupling agent, 3-5 parts catalyst.

4. The long-lasting anti-mildew silicone sealant according to claim 1, characterized in that, The silane coupling agent is 3-aminopropyltriethoxysilane; and / or... The pore-forming agent is 1,3,5-trimethylbenzene; and / or, The amine catalyst is a C1-C16 alkylamine.

5. The long-lasting anti-mildew silicone sealant according to claim 4, characterized in that, The amine catalyst is a C10-C14 alkylamine.

6. The long-lasting anti-mildew silicone sealant according to claim 1, characterized in that, The cyclodextrin is one or a combination of two or more of α-cyclodextrin, β-cyclodextrin, and γ-cyclodextrin; and / or, The antifungal agent is one or more of catechin, eugenol, vanillin, and cinnamic acid.

7. The long-lasting anti-mildew silicone sealant according to claim 6, characterized in that, The antifungal agent is cinnamic acid.

8. The long-lasting anti-mildew silicone sealant according to any one of claims 1-7, characterized in that, The mass ratio of the cyclodextrin inclusion complex to the silane coupling agent is 1:0.4-0.6; and / or, The mass ratio of the cyclodextrin inclusion complex to tetrabutyl silicate is 1:2.2-2.8; and / or, The mass ratio of tetrabutyl silicate to amine catalyst is 1:0.1-0.3; and / or, The mass ratio of tetrabutyl silicate to porogen is 1:0.07-0.11; and / or, The mass ratio of the monochlorotriazine-cyclodextrin to the antifungal agent is 1.5-2.5:

1.

9. The long-lasting anti-mildew silicone sealant according to claim 8, characterized in that, The mass ratio of tetrabutyl silicate to amine catalyst is 1:0.17-0.

22.

10. The long-lasting anti-mildew silicone sealant according to any one of claims 1-7, characterized in that, The preparation method of the cyclodextrin inclusion complex includes the following steps: dispersing monochlorotriazine-cyclodextrin in water at 50℃-90℃, and when cooled to 35℃-45℃, adding an alcoholic solution of antifungal agent dropwise under stirring, and stirring for 1h-6h, followed by crystallization and precipitation to obtain the cyclodextrin inclusion complex.

11. The long-lasting anti-mildew silicone sealant according to any one of claims 1-7, characterized in that, The volume ratio of ethanol to water in the ethanol-water solution is 1:3-10.

12. The long-lasting anti-mildew silicone sealant according to any one of claims 1-7, characterized in that, The α,ω-dihydroxypolydimethylsiloxane has a viscosity of 1 Pa·s-300 Pa·s at 25°C; and / or, The dimethyl silicone oil has a viscosity of 0.1 Pa·s to 1 Pa·s at 25°C; and / or, The inorganic filler is at least one of nano-activated calcium carbonate, heavy calcium carbonate, silica powder, and diatomaceous earth, and / or, The crosslinking agent is at least one selected from methyltrimethoxysilane, propyltrimethoxysilane, octyltrimethoxysilane, and phenyltrimethoxysilane; and / or, The coupling agent is at least one selected from γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane, γ-glycidyl etheroxypropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, and 3-isocyanate-propyltrimethoxysilane; and / or The catalyst is a titanate catalyst.

13. The long-lasting anti-mildew silicone sealant according to claim 12, characterized in that, The α,ω dihydroxy polydimethylsiloxane has a viscosity of 10 Pa·s-100 Pa·s at 25°C.

14. The long-lasting anti-mildew silicone sealant according to claim 12, characterized in that, The dimethyl silicone oil has a viscosity of 0.2 Pa·s to 0.5 Pa·s at 25°C.

15. The long-lasting anti-mildew silicone sealant according to claim 12, characterized in that, The catalyst is selected from at least one of tetraisopropyl titanate, tetrabutyl titanate, diisopropyl di(ethyl acetoacetate) titanate, dibutoxybis(ethyl acetoacetate) titanate, and diisobutyl di(ethyl acetoacetate) titanate.

16. A method for preparing a long-lasting anti-mildew silicone sealant according to any one of claims 1-15, characterized in that, Includes the following steps: (1) α,ω dihydroxy polydimethylsiloxane, CDs-SiO2, dimethyl silicone oil and inorganic filler were dehydrated and blended for 60 min to 120 min at a temperature of 90℃~120℃ and a vacuum degree of -0.08MPa~-0.1MPa, and the base material was obtained after cooling. (2) The base material is put into a mixer, and the crosslinking agent, coupling agent and catalyst are added. The mixture is mixed and reacted for 50 min to 120 min under the conditions of vacuum degree of -0.08MPa to -0.1MPa and stirring speed of 10Hz to 20Hz to obtain the long-lasting anti-mildew silicone sealant.

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