Flame-retardant mildew-resistant prepolymers, transparent flame-retardant mildew-resistant silicone sealants, and methods of making the same

Abstract

The application discloses a kind of flame-retardant mildew-proof prepolymer, transparent flame-retardant mildew-proof silicone sealant and preparation method thereof.The flame-retardant mildew-proof prepolymer is prepared from raw materials including the following components by weight: mildew-proof agent 0.5-10 parts, flame retardant 20-50 parts, tackifier composition 0.2-2 parts;The tackifier composition is composed of alkyl acetoacetate, trimethylsilyl ethyl acetate, 3-isocyanate propyl trimethoxysilane and polyether silicone oil.The transparent flame-retardant mildew-proof silicone sealant is prepared from raw materials including the following components: alkyl alkoxy-terminated polydimethylsiloxane, white carbon black, the flame-retardant mildew-proof prepolymer, crosslinking agent, catalyst, coupling agent.The transparent flame-retardant mildew-proof silicone sealant prepared by the application not only has very high transparency, but also has excellent flame-retardant effect, long-lasting mildew-resistant and antibacterial properties, and good bonding stability and mechanical strength.

Description

Technical Field

[0001] This invention belongs to the field of sealants, and in particular relates to a flame-retardant and mildew-resistant prepolymer, a transparent flame-retardant and mildew-resistant silicone sealant, and its preparation method. Background Technology

[0002] Silicone sealant is a polymer compound material with excellent adhesion. Its molecular backbone Si-O bond energy is much greater than that of C-C and CO bonds. It has good stability, weather resistance, environmental friendliness, fatigue resistance, and high elasticity. It is widely used in connecting or filling structures, joints, sealing, waterproofing, gas barrier, heat insulation and insulation and other scenarios.

[0003] With the development of home decoration, anti-mold sealants are widely used in kitchens and bathrooms, washbasins and countertops, and for sealing and fixing wardrobes to walls. Especially in the harsh and extreme temperature and humidity environment of southern regions, where mold easily grows, the anti-mold function of sealants during long-term use is put to a great test. Sealants on the market are prone to discoloration and mold growth over long-term use, affecting not only appearance but also potentially causing loss of adhesion. Furthermore, as people's living standards continue to improve, more application demands are being placed on sealants, such as the need for transparent appearance to suit certain special scenarios. With frequent cases of fires in homes, sealants in home decoration also require a certain degree of flame retardancy. Therefore, a transparent sealant product that combines anti-mold and flame retardant effects has significant application potential and economic value.

[0004] Patent application CN201410029398.1 discloses a single-component, mildew-resistant, transparent, de-alcoholized silicone sealant and its preparation method. It uses an organic arsenic compound with a polyether polyol as a carrier as a mildew inhibitor. Arsenic compounds are highly toxic to humans, and this sealant lacks flame retardancy, clearly failing to meet the contemporary home decoration requirements for non-toxic, harmless, safe, and environmentally friendly sealant products. Patent application CN201510644757.9 discloses a two-component epoxy-based mildew-resistant sealant. This product overcomes the poor mildew-resistant effect of traditional sealants and has a ceramic-glaze-like gloss after curing. However, it cannot address the transparency requirements in certain special scenarios, such as sealing glass gaps. Neither of the sealants in these two patents solves the multiple challenges of mildew resistance, flame retardancy, and transparency. Summary of the Invention

[0005] Therefore, the purpose of this invention is to provide a transparent flame-retardant and mildew-proof silicone sealant.

[0006] To achieve the above-mentioned objectives, the present invention includes the following technical solutions.

[0007] A flame-retardant and mildew-resistant prepolymer, prepared by weight from raw materials comprising the following components:

[0008] 0.5-10 parts of antifungal agent

[0009] 20-50 parts flame retardant

[0010] 0.2 to 2 parts of the tackifier composition;

[0011] The tackifier composition comprises alkyl acetoacetate, ethyl trimethylsilyl ester, 3-isocyanate-propyltrimethoxysilane, and polyether silicone oil.

[0012] In some embodiments, the alkyl acetoacetate is alkyl acetoacetate and / or alkyl acetoacetate.

[0013] In some embodiments, the polyether silicone oil has a viscosity of 1000 mPa·s to 5000 mPa·s at 25°C.

[0014] In some embodiments, the polyether silicone oil has a viscosity of 1000 mPa·s to 2000 mPa·s at 25°C.

[0015] In some embodiments, the mass ratio of alkyl acetoacetate, ethyl trimethylsilyl ester, 3-isocyanate-propyltrimethoxysilane, and polyether silicone oil in the tackifier composition is 1.8–2.2:0.8–1.2:1:4–6.

[0016] In some embodiments, the mass ratio of alkyl acetoacetate, ethyl trimethylsilyl ester, 3-isocyanate-propyltrimethoxysilane, and polyether silicone oil in the tackifier composition is 2:1:1:5.

[0017] In some embodiments, the flame-retardant and mildew-resistant prepolymer is prepared from raw materials comprising the following components, in parts by weight:

[0018] 3-8 parts of antifungal agent

[0019] 30-50 parts flame retardant

[0020] 0.5 to 1.5 parts of the tackifier composition.

[0021] In some embodiments, the flame-retardant and mildew-resistant prepolymer is prepared from raw materials comprising the following components, in parts by weight:

[0022] 5-7 parts of antifungal agent

[0023] 35-45 parts flame retardant

[0024] The tackifier composition is 0.8 to 1.2 parts.

[0025] In some embodiments, the flame retardant is selected from at least one of SFR100 flame retardant, triphenyl phosphate, and p-tert-butylphenyl diphenyl phosphate.

[0026] In some embodiments, the antifungal agent is selected from at least one of polyhexamethylene biguanide and isothiazolinone.

[0027] In some embodiments, the isothiazolinone is 2-methyl-4-isothiazolin-3-one.

[0028] The present invention also provides a method for preparing the above-mentioned flame-retardant and mildew-resistant prepolymer, comprising the following steps:

[0029] (1) The alkyl acetoacetate and the 3-isocyanate propyltrimethoxysilane are mixed evenly, and then the polyether silicone oil and trimethylsilyl ethyl acetate are added. After mixing evenly, a tackifier composition is obtained.

[0030] (2) Heat the thickener composition to 85°C to 95°C, add the mildew inhibitor and flame retardant, stir and react for 20 min to 40 min, and cool to obtain the flame retardant and mildew inhibitor prepolymer.

[0031] This invention also provides a transparent flame-retardant and mildew-resistant silicone sealant, prepared by weight from raw materials comprising the following components:

[0032]

[0033]

[0034] In some embodiments, the transparent flame-retardant and mildew-resistant silicone sealant, by weight, is prepared from raw materials comprising the following components:

[0035]

[0036] In some embodiments, the transparent flame-retardant and mildew-resistant silicone sealant, by weight, is prepared from raw materials comprising the following components:

[0037]

[0038] In some embodiments, the viscosity of the alkoxy-terminated polydimethylsiloxane is 1000 mPa·s to 50000 mPa·s.

[0039] In some embodiments, the viscosity of the alkoxy-terminated polydimethylsiloxane is 15000 mPa·s to 25000 mPa·s.

[0040] In some embodiments, the alkoxy-terminated polydimethylsiloxane is a methoxy-terminated polydimethylsiloxane.

[0041] In some embodiments, the silica is fumed silica treated with hexamethyldisilazane, with a specific surface area of ​​50 m² / g. 2 / g~380m 2 / g.

[0042] In some embodiments, the method for processing the silica includes the following steps: adding 0.8 to 1.2 parts of water and 2.5 to 3.5 parts of hexamethyldisilazane dropwise to 100 parts of fumed silica, stirring continuously for 2 to 4 hours; then heating to 115°C to 125°C, and stirring continuously for 5 to 6 hours until no obvious ammonia gas is emitted, thus obtaining the silica.

[0043] In some embodiments, the crosslinking agent is selected from at least one of methyltrimethoxysilane, methyltriethoxysilane, vinyltrimethoxysilane, and vinyltriethoxysilane.

[0044] In some embodiments, the crosslinking agent consists of methyltrimethoxysilane and vinyltrimethoxysilane in a mass ratio of 1:0.8-1.2.

[0045] In some embodiments, the catalyst is selected from diisopropyl bis(ethyl acetoacetate) titanate, diisobutyl bis(ethyl acetoacetate) titanate, and... At least one of the 9000 titanate chelates.

[0046] In some embodiments, the coupling agent is selected from one or more of γ-aminoethylaminopropyltrimethoxysilane, γ-isocyanate propyltriethoxysilane, γ-glycidyl etheroxypropyltrimethoxysilane, and β-(3,4-epoxycyclohexyl)-ethyltrimethoxysilane.

[0047] In some embodiments, the coupling agent is composed of γ-aminoethylaminopropyltrimethoxysilane, γ-glycidyl etheroxypropyltrimethoxysilane and β-(3,4-epoxycyclohexyl)-ethyltrimethoxysilane.

[0048] In some embodiments, the coupling agent is composed of γ-aminoethylaminopropyltrimethoxysilane, γ-glycidyl etheroxypropyltrimethoxysilane and β-(3,4-epoxycyclohexyl)-ethyltrimethoxysilane in a mass ratio of 2.5–3.5:1:1.5–2.5.

[0049] In some embodiments, the coupling agent is composed of γ-aminoethylaminopropyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane and β-(3,4-epoxycyclohexyl)-ethyltrimethoxysilane in a mass ratio of 3:1:2.

[0050] The present invention also provides a method for preparing the above-mentioned transparent flame-retardant and mildew-proof silicone sealant, comprising the following steps:

[0051] The alkoxy-terminated polydimethylsiloxane, silica, and flame-retardant and mildew-resistant prepolymer are dispersed and degassed for 10 to 40 minutes under a vacuum of -0.085 MPa to -0.095 MPa and a rotation speed of 200 to 500 rpm to obtain a base material. Under nitrogen protection, a crosslinking agent, a catalyst, and a coupling agent are added to the base material in sequence, and the mixture is stirred and degassed for 30 to 60 minutes under a vacuum of -0.085 MPa to -0.095 MPa and a rotation speed of 500 to 800 rpm to obtain the transparent flame-retardant and mildew-resistant silicone sealant.

[0052] The flame-retardant and mildew-resistant prepolymer, the transparent flame-retardant and mildew-resistant silicone sealant, and the preparation method thereof of the present invention have the following beneficial effects:

[0053] This invention selects highly transparent flame retardants and mildew inhibitors, and mixes them through a specific tackifier composition to create a flame-retardant and mildew-resistant prepolymer. The active groups on the surface of the tackifier composition link with both the flame retardant and mildew inhibitor to form the prepolymer, making the mildew inhibitor component more stable in everyday environments, less prone to decomposition, and exhibiting better antibacterial and mildew-resistant properties. When prepared into a silicone sealant with alkoxy-terminated polydimethylsiloxane, silica, and other components, it exhibits excellent flame-retardant and mildew-resistant effects. Furthermore, the flame retardants and mildew inhibitors selected in this invention have a synergistic mildew-resistant effect in the sealant system; simultaneously, when exposed to open flame, the mildew inhibitor component in the prepolymer can also react with the flame retardant, rapidly decomposing to generate gas that prevents further contact between the sealant and oxygen, thereby exerting a strong synergistic flame-retardant effect. Furthermore, through the combination of a titanate catalyst and a specific coupling agent, the resulting sealant product possesses excellent anti-yellowing properties, resistance to water vapor corrosion, and does not yellow or discolor after long-term use in a humid environment after curing, demonstrating stable performance.

[0054] Under the above-described technical concept, compared with existing sealants, the transparent flame-retardant and mildew-proof silicone sealant prepared by this invention not only has extremely high transparency, remaining transparent after curing and aesthetically pleasing, but also possesses excellent flame-retardant and fire-retardant effects as well as long-lasting mildew-proof and antibacterial properties. It exhibits excellent mildew-proof and antibacterial effects when applied to kitchen stoves, sinks, bathrooms, and other similar locations, and also has a certain flame-retardant effect against open flames. Furthermore, this sealant possesses good adhesive stability and mechanical strength, showing excellent adhesive stability to materials such as marble, stainless steel, and ceramics. Simultaneously, this sealant product is a de-alcoholized system, releasing small-molecule methanol during the curing process, making it safe, environmentally friendly, and non-toxic. After curing, the sealant product of this invention can achieve stable and reliable adhesion, highly effective mildew prevention, and flame-retardant and fire-proof functions even in long-term oil and moisture environments.

[0055] The preparation method of the transparent flame-retardant and mildew-proof silicone sealant of the present invention has a simple production process, readily available raw materials, high industrial value, and the product is environmentally friendly and non-toxic, thus possessing excellent economic benefits and application value. Detailed Implementation

[0056] 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.

[0057] 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.

[0058] The terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, apparatus, product, or device that includes a series of steps is not limited to the steps or modules listed, but may optionally include steps not listed, or may optionally include other steps inherent to such process, method, product, or device.

[0059] In this invention, "multiple" refers to two or more. "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, or B alone. The character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0060] The following are specific examples.

[0061] Unless otherwise specified, the "parts" used in the following examples refer to parts by weight.

[0062] The fumed silica in the following examples is fumed silica treated with hexamethyldisilazane, with a specific surface area of ​​100–300 m². 2 / g, the processing method is as follows: At room temperature, first add 100 parts of fumed silica to the reaction vessel, then add 1 part of water and 3 parts of hexamethyldisilazane dropwise under slow stirring, and continue stirring for 3 hours. Then raise the temperature to 120℃ and continue stirring for 5-6 hours until no obvious ammonia gas is emitted, thus obtaining the fumed silica for the experiment.

[0063] Example 1

[0064] The flame-retardant and mildew-resistant prepolymer provided in this embodiment is prepared by the following steps:

[0065] (1) Add 0.2 parts of methyl acetoacetate and 0.1 parts of 3-isocyanate-propyltrimethoxysilane to a flask and stir continuously for 15 min at a constant temperature of 25°C. Then add 0.5 parts of polyether silicone oil (viscosity of 1500 mPa·s at 25°C) and 0.1 parts of trimethylsilyl ethyl acetate. Continue to mix evenly to obtain a thickener composition.

[0066] (2) Heat 1 part of the obtained tackifier composition to 90°C, add 6 parts of polyhexamethylene biguanide and 40 parts of SFR100 flame retardant in sequence, stir and react for 30 min, and obtain flame retardant and mildew-proof prepolymer after cooling.

[0067] The transparent flame-retardant and mildew-proof silicone sealant provided in this embodiment is prepared by the following steps:

[0068] 100 parts of methoxy-terminated polydimethylsiloxane with a viscosity of 20000 mPa·s, 50 parts of fumed silica, and 40 parts of flame-retardant and mildew-resistant prepolymer were added to an adhesive mixer. The mixture was stirred, dispersed, and degassed at 300 rpm under a vacuum of -0.090 MPa for 15 minutes to obtain the base material. Under nitrogen protection, 3 parts of vinyltrimethoxysilane, 3 parts of methyltrimethoxysilane, and 4 parts of diisobutyl bis(ethyl acetoacetate) titanate were added sequentially to the obtained base material, and the mixture was stirred and reacted for 15 minutes. Finally, 1 part of coupling agent was added (the components of the coupling agent were pre-mixed uniformly in a mass ratio of γ-aminoethylaminopropyltrimethoxysilane, γ-glycidyl etheroxypropyltrimethoxysilane, and β-(3,4-epoxycyclohexyl)-ethyltrimethoxysilane at 3:1:2). The mixture was then stirred and degassed at 600 rpm under a vacuum of -0.09 MPa for 40 minutes to obtain the sealant.

[0069] Example 2

[0070] The flame-retardant and mildew-resistant prepolymer provided in this embodiment is prepared by the following steps:

[0071] (1) Add 0.2 parts of ethyl acetoacetate and 0.1 parts of 3-isocyanate-propyltrimethoxysilane to a flask and stir continuously for 15 min at a constant temperature of 25°C. Then add 0.5 parts of polyether silicone oil (viscosity of 1500 mPa·s at 25°C) and 0.1 parts of trimethylsilyl ethyl acetate and continue to mix evenly to obtain a thickener composition.

[0072] (2) Heat 1 part of the obtained tackifier composition to 90°C, add 3 parts of polyhexamethylene biguanide, 3 parts of 2-methyl-4-isothiazolin-3-one and 40 parts of triphenyl phosphate in sequence, stir and react for 30 min, and obtain flame retardant and mildew-resistant prepolymer after cooling.

[0073] The transparent flame-retardant and mildew-proof silicone sealant provided in this embodiment is prepared by the following steps:

[0074] 100 parts of methoxy-terminated polydimethylsiloxane (20000 mPa·s), 50 parts of fumed silica, and 50 parts of flame-retardant and mildew-resistant prepolymer were added to an adhesive mixer. The mixture was stirred, dispersed, and degassed at 300 rpm for 15 minutes under a vacuum of -0.090 MPa to obtain the base material. Under nitrogen protection, 3 parts of vinyltrimethoxysilane, 3 parts of methyltrimethoxysilane, and DuPont... Four parts of 9000 titanate chelate were stirred for 15 min. Finally, one part of coupling agent was added (the components of the coupling agent were pre-mixed uniformly in a mass ratio of 3:1:2 for γ-aminoethylaminopropyltrimethoxysilane, γ-glycidyl etheroxypropyltrimethoxysilane, and β-(3,4-epoxycyclohexyl)-ethyltrimethoxysilane), and the mixture was degassed and stirred for 40 min under a vacuum of -0.090 MPa and a rotation speed of 600 rpm to obtain the sealant.

[0075] Example 3

[0076] The flame-retardant and mildew-resistant prepolymer provided in this embodiment is prepared by the following steps:

[0077] (1) Add 0.1 parts of ethyl acetoacetate, 0.1 parts of methyl acetoacetate and 0.1 parts of 3-isocyanate-propyltrimethoxysilane to a flask and stir continuously for 15 min at a constant temperature of 25°C. Then add 0.5 parts of polyether silicone oil (viscosity of 1500 mPa·s at 25°C) and 0.1 parts of trimethylsilyl ethyl acetate and continue to mix evenly to obtain a thickener composition.

[0078] (2) Heat 1 part of the obtained tackifier composition to 90°C, add 6 parts of 2-methyl-4-isothiazolin-3-one and 40 parts of p-tert-butylphenyl diphenyl phosphate in sequence, stir and react for 30 min, and obtain flame retardant and mildew-resistant prepolymer after cooling.

[0079] The transparent flame-retardant and mildew-proof silicone sealant provided in this embodiment is prepared by the following steps:

[0080] 100 parts of methoxy-terminated polydimethylsiloxane with a viscosity of 20000 mPa·s, 50 parts of fumed silica, and 40 parts of flame-retardant and mildew-resistant prepolymer were added to an adhesive mixer. The mixture was stirred and dispersed at 300 rpm for 15 minutes under a vacuum of -0.090 MPa to obtain the base material. Under nitrogen protection, 3 parts of vinyltrimethoxysilane, 3 parts of methyltrimethoxysilane, and 4 parts of diisobutyl bis(acetoacetate)titanate were added sequentially to the obtained base material, and the mixture was stirred and reacted for 15 minutes. Finally, 1 part of coupling agent was added (the components of the coupling agent were pre-mixed uniformly in a mass ratio of γ-aminoethylaminopropyltrimethoxysilane, γ-glycidyl etheroxypropyltrimethoxysilane, and β-(3,4-epoxycyclohexyl)-ethyltrimethoxysilane at 3:1:2). The mixture was then stirred and dispersed at 600 rpm for 40 minutes under a vacuum of -0.090 MPa to obtain the sealant.

[0081] Example 4

[0082] The flame-retardant and mildew-resistant prepolymer provided in this embodiment is prepared by the following steps:

[0083] (1) Add 0.1 parts of ethyl acetoacetate, 0.1 parts of methyl acetoacetate and 0.1 parts of 3-isocyanate-propyltrimethoxysilane to a flask and stir continuously for 15 min at a constant temperature of 25°C. Then add 0.5 parts of polyether silicone oil (viscosity of 1500 mPa·s at 25°C) and 0.1 parts of trimethylsilyl ethyl acetate and continue to mix evenly to obtain a thickener composition.

[0084] (2) Heat 1 part of the obtained tackifier composition to 90°C and add 3 parts of polyhexamethylene biguanide, 3 parts of 2-methyl-4-isothiazolin-3-one, 20 parts of SFR100 flame retardant and 20 parts of tert-butylphenyl diphenyl phosphate in sequence. Stir and react for 30 min. After cooling, obtain the flame retardant and mildew-proof prepolymer.

[0085] The transparent flame-retardant and mildew-proof silicone sealant provided in this embodiment is prepared by the following steps:

[0086] 100 parts of methoxy-terminated polydimethylsiloxane with a viscosity of 20000 mPa·s, 50 parts of fumed silica, and 40 parts of flame-retardant and mildew-resistant prepolymer were added to an adhesive mixer. The mixture was stirred, dispersed, and degassed at 300 rpm under a vacuum of -0.090 MPa for 15 minutes to obtain the base material. Under nitrogen protection, 3 parts of vinyltrimethoxysilane, 3 parts of methyltrimethoxysilane, and 4 parts of diisopropyl bis(ethyl acetoacetate) titanate were added sequentially to the obtained base material, and the mixture was stirred and reacted for 15 minutes. Finally, 1 part of coupling agent was added (the components of the coupling agent were pre-mixed uniformly in a mass ratio of γ-aminoethylaminopropyltrimethoxysilane, γ-glycidyl etheroxypropyltrimethoxysilane, and β-(3,4-epoxycyclohexyl)-ethyltrimethoxysilane at 3:1:2). The mixture was then stirred and degassed at 600 rpm under a vacuum of -0.090 MPa for 40 minutes to obtain the sealant.

[0087] Comparative Example 1

[0088] The flame-retardant and mildew-resistant prepolymer provided in this comparative example is prepared by the following steps:

[0089] (1) Add 0.2 parts of methyl acetoacetate and 0.1 parts of 3-isocyanate-propyltrimethoxysilane to a flask and stir continuously for 15 min at a constant temperature of 25°C. Then add 0.5 parts of polyether silicone oil (viscosity of 1500 mPa·s at 25°C) and 0.1 parts of trimethylsilyl ethyl acetate and continue to mix evenly to obtain a thickener composition.

[0090] (2) Heat 1 part of the obtained tackifier composition to 90°C, add 40 parts of SFR100 flame retardant, stir and react for 30 min, and cool to obtain flame retardant and mildew-proof prepolymer.

[0091] The transparent, flame-retardant, and mildew-resistant silicone sealant provided in this comparative example is prepared by the following steps:

[0092] 100 parts of methoxy-terminated polydimethylsiloxane with a viscosity of 20000 mPa·s, 50 parts of fumed silica, and 40 parts of flame-retardant and mildew-resistant prepolymer were added to an adhesive mixer. The mixture was stirred, dispersed, and degassed at 300 rpm under a vacuum of -0.090 MPa for 15 minutes to obtain the base material. Under nitrogen protection, 3 parts of vinyltrimethoxysilane, 3 parts of methyltrimethoxysilane, and 4 parts of tetraisopropyl bis(ethyl acetoacetate) titanate were added sequentially to the obtained base material, and the mixture was stirred and reacted for 15 minutes. Finally, 1 part of coupling agent was added (the components of the coupling agent were pre-mixed uniformly in a mass ratio of γ-aminoethylaminopropyltrimethoxysilane, γ-glycidyl etheroxypropyltrimethoxysilane, and β-(3,4-epoxycyclohexyl)-ethyltrimethoxysilane at 3:1:2). The mixture was then stirred and degassed at 600 rpm under a vacuum of -0.09 MPa for 40 minutes to obtain the sealant.

[0093] Comparative Example 2

[0094] The flame-retardant and mildew-resistant prepolymer provided in this comparative example is prepared by the following steps:

[0095] (1) Add 0.2 parts of methyl acetoacetate and 0.1 parts of 3-isocyanate-propyltrimethoxysilane to a flask and stir continuously for 15 min at a constant temperature of 25°C. Then add 0.5 parts of polyether silicone oil (viscosity of 1500 mPa·s at 25°C) and 0.1 parts of trimethylsilyl ethyl acetate and continue to mix evenly to obtain a thickener composition.

[0096] (2) Heat 1 part of the obtained tackifier composition to 90°C, add 6 parts of polyhexamethylene biguanide, stir and react for 30 min, and cool to obtain flame retardant and mildew resistant prepolymer.

[0097] The transparent, flame-retardant, and mildew-resistant silicone sealant provided in this comparative example is prepared by the following steps:

[0098] 100 parts of methoxy-terminated polydimethylsiloxane with a viscosity of 20000 mPa·s, 50 parts of fumed silica, and 40 parts of flame-retardant and mildew-resistant prepolymer were added to an adhesive mixer. The mixture was dispersed and degassed at 300 rpm under a vacuum of -0.090 MPa for 15 minutes to obtain the base material. Under nitrogen protection, 3 parts of vinyltrimethoxysilane, 3 parts of methyltrimethoxysilane, and 4 parts of diisobutyl bis(acetoacetate)titanate were added sequentially to the obtained base material, and the mixture was stirred and reacted for 15 minutes. Finally, 1 part of coupling agent was added (the components of the coupling agent were pre-mixed uniformly in a mass ratio of γ-aminoethylaminopropyltrimethoxysilane, γ-glycidyl etheroxypropyltrimethoxysilane, and β-(3,4-epoxycyclohexyl)-ethyltrimethoxysilane at 3:1:2). The mixture was then degassed and stirred at 600 rpm under a vacuum of -0.09 MPa for 40 minutes to obtain the sealant.

[0099] Comparative Example 3

[0100] The transparent, flame-retardant, and mildew-resistant silicone sealant provided in this comparative example is prepared by the following steps:

[0101] 100 parts of methoxy-terminated polydimethylsiloxane with a viscosity of 20000 mPa·s, 50 parts of fumed silica, 6 parts of polyhexamethylene biguanide, and 40 parts of SFR100 flame retardant were added to a bonding machine. The mixture was stirred, dispersed, and degassed at 300 rpm for 15 minutes under a vacuum of -0.090 MPa to obtain the base material. Under nitrogen protection, 3 parts of vinyltrimethoxysilane, 3 parts of methyltrimethoxysilane, and 4 parts of diisopropyl bis(ethyl acetoacetate) titanate were added sequentially to the obtained base material, and the mixture was stirred and reacted for 15 minutes. Finally, add 1 part of coupling agent (the components of the coupling agent are pre-mixed evenly in a mass ratio of 3:1:2 for γ-aminoethylaminopropyltrimethoxysilane, γ-glycidyl etheroxypropyltrimethoxysilane, and β-(3,4-epoxycyclohexyl)-ethyltrimethoxysilane), and stir for 40 min under vacuum of -0.09 MPa and rotation speed of 600 rpm to obtain the sealant.

[0102] Comparative Example 4

[0103] The flame-retardant and mildew-resistant prepolymer provided in this comparative example is prepared by the following steps:

[0104] (1) 0.1 part of 3-isocyanate-propyltrimethoxysilane was added to a flask and stirred continuously for 15 min at a constant temperature of 25°C. Then, 0.5 part of polyether silicone oil (viscosity of 1500 mPa·s at 25°C) and 0.1 part of trimethylsilyl ethyl acetate were added and mixed evenly to obtain a thickener composition.

[0105] (2) Heat 1 part of the obtained tackifier composition to 90°C, add 6 parts of polyhexamethylene biguanide and 40 parts of SFR100 flame retardant in sequence, stir and react for 30 min, and obtain flame retardant and mildew-proof prepolymer after cooling.

[0106] The transparent, flame-retardant, and mildew-resistant silicone sealant provided in this comparative example is prepared by the following steps:

[0107] 100 parts of methoxy-terminated polydimethylsiloxane with a viscosity of 20000 mPa·s, 50 parts of fumed silica, and 40 parts of flame-retardant and mildew-resistant prepolymer were added to an adhesive mixer. The mixture was dispersed and degassed at 300 rpm under a vacuum of -0.090 MPa for 15 minutes to obtain the base material. Under nitrogen protection, 3 parts of vinyltrimethoxysilane, 3 parts of methyltrimethoxysilane, and 4 parts of diisobutyl bis(acetoacetate)titanate were added sequentially to the obtained base material, and the mixture was stirred and reacted for 15 minutes. Finally, 1 part of coupling agent was added (the components of the coupling agent were pre-mixed uniformly in a mass ratio of γ-aminoethylaminopropyltrimethoxysilane, γ-glycidyl etheroxypropyltrimethoxysilane, and β-(3,4-epoxycyclohexyl)-ethyltrimethoxysilane at 3:1:2). The mixture was then degassed and stirred at 600 rpm under a vacuum of -0.09 MPa for 40 minutes to obtain the sealant.

[0108] Comparative Example 5

[0109] The flame-retardant and mildew-resistant prepolymer provided in this comparative example is prepared by the following steps:

[0110] (1) Add 0.2 parts of methyl acetoacetate to a flask and stir continuously for 15 minutes at a constant temperature of 25°C. Then add 0.5 parts of polyether silicone oil (viscosity of 1500 mPa·s at 25°C) and 0.1 parts of trimethylsilyl ethyl acetate. Continue to mix evenly to obtain a thickener composition.

[0111] (2) Heat 1 part of the obtained tackifier composition to 90°C, add 6 parts of polyhexamethylene biguanide and 40 parts of SFR100 flame retardant in sequence, stir and react for 30 min, and obtain flame retardant and mildew-proof prepolymer after cooling.

[0112] The transparent, flame-retardant, and mildew-resistant silicone sealant provided in this comparative example is prepared by the following steps:

[0113] 100 parts of methoxy-terminated polydimethylsiloxane with a viscosity of 20000 mPa·s, 50 parts of fumed silica, and 40 parts of flame-retardant and mildew-resistant prepolymer were added to an adhesive mixer. The mixture was dispersed and degassed at 300 rpm under a vacuum of -0.090 MPa for 15 minutes to obtain the base material. Under nitrogen protection, 3 parts of vinyltrimethoxysilane, 3 parts of methyltrimethoxysilane, and 4 parts of diisopropyl bis(ethyl acetoacetate) titanate were added sequentially to the obtained base material, and the mixture was stirred and reacted for 15 minutes. Finally, 1 part of coupling agent was added (the components of the coupling agent were pre-mixed uniformly in a mass ratio of γ-aminoethylaminopropyltrimethoxysilane, γ-glycidyl etheroxypropyltrimethoxysilane, and β-(3,4-epoxycyclohexyl)-ethyltrimethoxysilane at 3:1:2). The mixture was then degassed and stirred at 600 rpm under a vacuum of -0.09 MPa for 40 minutes to obtain the sealant.

[0114] Comparative Example 6

[0115] The flame-retardant and mildew-resistant prepolymer provided in this comparative example is prepared by the following steps:

[0116] (1) Add 0.2 parts of methyl acetoacetate and 0.1 parts of 3-isocyanate-propyltrimethoxysilane to a flask and stir continuously for 15 minutes at a constant temperature of 25°C. Then add 0.5 parts of polyether silicone oil (viscosity of 1500 mPa·s at 25°C) and continue to mix evenly to obtain a thickener composition.

[0117] (2) Heat 1 part of the obtained tackifier composition to 90°C, add 6 parts of polyhexamethylene biguanide and 40 parts of SFR100 flame retardant in sequence, stir and react for 30 min, and obtain flame retardant and mildew-proof prepolymer after cooling.

[0118] The transparent, flame-retardant, and mildew-resistant silicone sealant provided in this comparative example is prepared by the following steps:

[0119] 100 parts of methoxy-terminated polydimethylsiloxane with a viscosity of 20000 mPa·s, 50 parts of fumed silica, and 40 parts of flame-retardant and mildew-resistant prepolymer were added to an adhesive mixer. The mixture was dispersed and degassed at 300 rpm under a vacuum of -0.090 MPa for 15 minutes to obtain the base material. Under nitrogen protection, 3 parts of vinyltrimethoxysilane, 3 parts of methyltrimethoxysilane, and 4 parts of diisobutyl bis(acetoacetate)titanate were added sequentially to the obtained base material, and the mixture was stirred and reacted for 15 minutes. Finally, 1 part of coupling agent was added (the components of the coupling agent were pre-mixed uniformly in a mass ratio of γ-aminoethylaminopropyltrimethoxysilane, γ-glycidyl etheroxypropyltrimethoxysilane, and β-(3,4-epoxycyclohexyl)-ethyltrimethoxysilane at 3:1:2). The mixture was then degassed and stirred at 600 rpm under a vacuum of -0.09 MPa for 40 minutes to obtain the sealant.

[0120] The transparent flame-retardant and mildew-resistant silicone sealants prepared in Examples 1-4 and Comparative Examples 1-6 were tested for surface drying time according to GB / T13477.5; mildew resistance according to GR / T1741-2007; flame retardancy according to GB / T 2408 (plastics flammability test); and tensile strength according to GB / T528-2009. The flame retardancy rating was tested using the vertical burning test method according to the material classification of UL94V-0, ULV-1, and ULV-2. Adhesion to the substrate was tested according to Method II, Appendix D1.2 of GB / T 16776-2005.

[0121] The test results are shown in Table 1 below.

[0122] Table 1

[0123]

[0124]

[0125] As can be seen from the test results in Table 1, the sealants of Examples 1 to 4 have excellent adhesion to marble and ceramic substrates, excellent anti-mildew effect with long-term use, transparent after curing, beautiful and elegant, do not yellow or change color with long-term use, and also have excellent flame retardant properties, are environmentally friendly, safe, non-toxic and harmless.

[0126] The comparison results between Comparative Examples 1-2 and Example 1 show that adding only a flame retardant or only a mildew inhibitor significantly affects the flame retardant and mildew-resistant properties of the sealant system. Adding only a flame retardant without a mildew inhibitor fails to achieve the V-0 flame retardant rating; adding only a mildew inhibitor without a flame retardant results in a gradual decline in the mildew-resistant properties of the sealant over long-term use. This indicates that the flame retardant and mildew inhibitor selected in this invention have a synergistic flame retardant and mildew-resistant effect in the sealant system of this invention, and their combined addition achieves excellent flame retardant and mildew-resistant effects.

[0127] The comparison results between Comparative Examples 3-6 and Example 1 show that the flame-retardant and mildew-resistant silicone sealant prepared by reacting the tackifier composition prepared in this invention with flame retardants and mildew inhibitors, and then using alkoxy-terminated polydimethylsiloxane and other raw materials, exhibits better antibacterial and mildew-resistant effects than the flame-retardant and mildew-resistant silicone sealant obtained by directly adding flame retardants and mildew inhibitors through blending. Furthermore, the absence of any component in the tackifier composition prepared in this invention will affect the subsequent long-term antibacterial and mildew-resistant effects of the sealant, reducing the bonding stability of materials such as marble, ceramics, and stainless steel cement. The tackifier composition prepared in this invention can combine the mildew inhibitor and flame retardant components to form a prepolymer, which can stably exert a long-lasting antibacterial and mildew-resistant effect in the sealant.

[0128] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0129] 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 flame retardant mildewcide prepolymer characterized in that, Prepared from raw materials comprising the following components by weight: Antifungal agent 0.5-10 parts Flame retardant 20-50 parts Adhesion promoter composition 0.2-2 parts; The adhesion promoter composition consists of alkyl acetoacetate, ethyl trimethylsilyl acetate, 3-isocyanate propyl trimethoxysilane and polyether silicone oil; The flame retardant is selected from at least one of SFR100 type flame retardant, triphenyl phosphate and p-tert-butyl phenyl diphenyl phosphate; The antifungal agent is selected from at least one of polyhexamethylene biguanide and isothiazolinone.

2. The flame retardant mildewcide prepolymer of claim 1, wherein The alkyl acetoacetate is alkyl methyl acetoacetate and / or alkyl ethyl acetoacetate; and / or, The polyether silicone oil has a viscosity of 1000 mPa·s-5000 mPa·s at 25℃; and / or, The mass ratio of alkyl acetoacetate, ethyl trimethylsilyl acetate, 3-isocyanate propyl trimethoxysilane and polyether silicone oil in the adhesion promoter composition is 1.8-2.2:0.8-1.2:1:4-6.

3. The flame retardant mildewcide prepolymer of claim 1, wherein Prepared from raw materials comprising the following components by weight: Antifungal agent 3-8 parts Flame retardant 30-50 parts Adhesion promoter composition 0.5-1.5 parts.

4. The flame retardant mildewcide prepolymer according to any one of claims 1-3, wherein, The isothiazolinone is 2-methyl-4-isothiazolin-3-one.

5. A process for the preparation of the flame retardant mildewcide prepolymer as claimed in any one of claims 1 to 4, characterized in that, Comprising the following steps: (1) Mix the alkyl acetoacetate and the 3-isocyanate propyl trimethoxysilane uniformly, then add the polyether silicone oil and ethyl trimethylsilyl acetate, continue to mix uniformly to obtain the adhesion promoter composition; (2) Heat the adhesion promoter composition to 85℃-95℃, add the antifungal agent and flame retardant, stir for 20 min-40 min, cool, and the flame retardant and antifungal prepolymer is obtained.

6. A clear, fire-retardant, mildew-resistant silicone sealant, characterized by, Prepared from raw materials comprising the following components by weight: Alkyl methoxyl-terminated polydimethylsiloxane 100 parts White carbon black 10-70 parts The flame retardant and antifungal prepolymer of any one of claims 1-4 20-60 parts Crosslinking agent 2-10 parts Catalyst 2-6 parts Coupling agent 0.1-2 parts.

7. The clear, flame-retardant, mildew-resistant silicone sealant of claim 6, wherein, Prepared from raw materials comprising the following components:

8. The clear, flame-retardant, mildew-resistant silicone sealant according to claim 6 or 7, characterized in that The alkyl methoxyl-terminated polydimethylsiloxane has a viscosity of 1000 mPa·s-50000 mPa·s; and / or, The white carbon black is a hexamethyldisilazane-treated fumed white carbon black having a specific surface area of 50 m 2 / g to 380 m 2 / g; and / or, The crosslinking agent is selected from at least one of methyl trimethoxysilane, methyl triethoxysilane, vinyl trimethoxysilane and vinyl triethoxysilane; and / or, The catalyst is selected from the group consisting of diisopropyltitanium bis(acetoacetate ethyl ester), diisobutyltitanium bis(acetoacetate ethyl ester), and at least one of a titanate chelate; and / or, The coupling agent is selected from one or more of γ-aminoethyl aminopropyl trimethoxysilane, γ-isocyanate propyl triethoxysilane, γ-glycidyl ether propyl trimethoxysilane and β-(3,4-epoxy cyclohexyl)-ethyl trimethoxysilane.

9. The clear, fire-retardant, mildew-resistant silicone sealant of claim 8, wherein, The alkyl methoxyl-terminated polydimethylsiloxane is methoxyl-terminated polydimethylsiloxane.

10. The clear, fire-retardant, mildew-resistant silicone sealant of claim 8, wherein, The crosslinking agent consists of methyl trimethoxysilane and vinyl trimethoxysilane in a mass ratio of 1:0.8-1.2; and / or, The coupling agent consists of γ-aminoethyl aminopropyl trimethoxysilane, γ-glycidyl ether propyl trimethoxysilane and β-(3,4-epoxy cyclohexyl)-ethyl trimethoxysilane in a mass ratio of 2.5-3.5:1:1.5-2.

5.

11. A process for the preparation of a transparent fire-retardant mildew-resistant silicone sealant according to any one of claims 6 to 10, characterized in that, Comprising the following steps: The alkoxyl-terminated polydimethylsiloxane, the white carbon black and the flame-retardant and mildew-proof prepolymer are dispersed and defoamed under the conditions of a vacuum degree of-0.085 MPa to-0.095 MPa and a rotating speed of 200 rpm to 500 rpm for 10 min to 40 min to obtain a base; the crosslinking agent, the catalyst and the coupling agent are sequentially added into the base under nitrogen protection, and the mixture is stirred and defoamed under the conditions of a vacuum degree of-0.085 MPa to-0.095 MPa and a rotating speed of 500 rpm to 800 rpm for 30 min to 60 min, so that the transparent flame-retardant and mildew-proof silicone sealant is obtained.

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