Two-component flame-retardant and mildew-proof silicone sealant and manufacturing method thereof

Abstract

The present invention discloses a two-component flame-retardant and mildew-proof silicone sealant and a manufacturing method thereof; the provided silicone sealant is mainly used for bonding, sealing and circuit protection of electronic components of various types of kitchen and bathroom appliances such as disinfection cabinets, range hoods, electric water heaters, etc., and meets the application requirements of household kitchen and bathroom appliances, catering industry, and medium and large canteen kitchen appliances. The market potential is very huge and meets the mildew-proof and fire-retardant requirements of sealants under harsh conditions.

Description

Technical Field

[0001] The invention relates to the field of polymer sealing materials, and in particular to a two-component flame-retardant and mildew-proof silicone sealant and a manufacturing method thereof. Background Art

[0002] Silicone sealant material is the most widely used polymer compound material at present. It is divided into two types according to the packaging form: single component and two components. Although there are many types of two-component silicone sealants at present, their functions are relatively single. According to the national standard "GB4706.107-2012 Special requirements for safety of integrated kitchen appliances for household and similar electrical appliances", the sealing materials of kitchen and bathroom appliances need to have not only good sealing performance, but also mildew-proof and flame-retardant composite functions. Ordinary two-component silicone sealants have low fire retardant and flame-retardant properties, and basically no bactericidal and mildew-proof properties. In view of this deficiency, a 1:1 condensation type two-component flame-retardant and mildew-proof silicone sealant is invented.

[0003] The invention has the advantages of fast curing speed, fast strength, deep curing in a confined space, simple construction, and can be produced on automated glue-spraying equipment, and is suitable for large-scale industrial production. The invention is mainly aimed at bonding, sealing, and circuit protection of electronic components of various types of kitchen and bathroom appliances such as disinfection cabinets, range hoods, electric water heaters, etc., meeting the application requirements of household kitchen and bathroom, catering industry, and medium and large canteen kitchen appliances. The market potential is very huge and meets the requirements of mildew prevention and fire retardancy of sealants under harsh conditions. Summary of the invention

[0004] The present invention is achieved through the following technical solutions:

[0005] A method for preparing alkoxy-terminated polydimethylsiloxane comprises the following steps:

[0006] (1) placing α,ω-dihydroxy polydimethylsiloxane in a container at room temperature, adding a capping agent and mixing for 30-90 minutes, and introducing nitrogen protection throughout the process; the capping agent is a mixture of methyltrimethoxysilane and vinyltrimethoxysilane;

[0007] (2) After adding the end-capping catalyst, the temperature is kept at 50-80° C. for reaction for 20-60 minutes. After the reaction is completed, the temperature is raised to 120-140° C. for vacuum removal of low molecular weight substances for 60-120 minutes, and the temperature is lowered to obtain alkoxy-end-capped polydimethylsiloxane.

[0008] Preferably, the mass ratio of the α,ω-dihydroxypolydimethylsiloxane, the end-capping agent and the catalyst is 1:(0.02-0.1):(0.02-0.1); the α,ω-dihydroxypolydimethylsiloxane is a hydroxyl-terminated short-chain linear polysiloxane; and the vacuum degree when removing low molecular weight substances and water in the system in step (2) is -0.08 to -0.1 MPa.

[0009] Preferably, the blocking catalyst is one or two of cyclohexanone oxime, potassium hydroxide, potassium acetate and primary amine.

[0010] The present invention further provides a two-component flame retardant and mildew-proof silicone sealant, comprising the following components in parts by weight:

[0011] Component A:

[0012]

[0013] Component B:

[0014]

[0015]

[0016] Preferably, the filler is one or more of heavy calcium carbonate, activated calcium carbonate, quartz powder, talc, mica powder, kaolin, wollastonite, calcium silicate, barium sulfate, magnesium silicate, aluminum hydroxide, magnesium hydroxide, montmorillonite, aluminum oxide, magnesium oxide, zinc oxide, aluminum nitride, and boron nitride.

[0017] Preferably, the crosslinking agent includes: at least one of methyltrimethoxysilane, methyl orthosilicate, propyltrimethoxysilane, polymethyltriethoxysilane propyl orthosilicate, vinyltrimethoxysilane, methyltriethylsilane, methylpropyldimethoxysilane, methylpropyldiethoxysilane, vinyltriethoxysilane, propyltriethoxysilane, methylvinyldimethoxysilane, polymethyltrimethoxysilane, polymethyltriethoxysilane, polypropyltrimethoxysilane, 1,2-bis(trimethoxysilyl) and 1,2-bis(triethoxysilyl).

[0018] Preferably, the flame retardant is at least one of spherical aluminum hydroxide, spherical magnesium hydroxide, nano zinc carbonate, magnesium carbonate, zinc borate, montmorillonite, glass fiber, antimony trioxide, ammonium polyphosphate and diatomaceous earth.

[0019] Preferably, the coupling agent includes chloropropyl triethoxysilane, isocyanate propyl trimethoxysilane, γ-aminopropyl trimethoxysilane, γ-aminopropyl triethoxysilane, N-(β-aminoethyl)-γ-aminopropyl triethoxysilane, bis-[3-(trimethoxysilyl)-propyl]-ethylenediamine, bis-[3-(triethoxysilyl)-propyl]-ethylenediamine, N-[3(trimethoxysilyl)-propyl]-n-butylamine, N,N-dimethyl-3-aminopropyl trimethoxysilane, N-n-butyl-3-aminopropyl At least one of triethoxysilane, hexamethyldisilazane, γ-(2,3-epoxypropyloxy)propyltrimethoxysilane, γ-(2,3-epoxypropyloxy)propyltriethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltri(3-oxysilane), 2-(3,4-epoxycyclohexyl)ethyltriethoxysilane, 2-cyanoethyltriethoxysilane, ureidopropyltriethoxysilane, 3-methacryloxypropyltrimethoxysilane, isocyanatepropyltriethoxysilane and vinyltri(2-methoxyethoxy)silane.

[0020] Preferably, the mildew preventer is at least one of disulfide-2,2-bis(N-methylbenzamide), 5-chloro-2methyl-4-isothiazoline-3-one, methyl 4-isothiazoline-3-one, 1,2-benzisothiazolin-3-one, n-octyl 4-isothiazoline-3-one, and dimethyl fumarate.

[0021] Preferably, the catalyst is at least one of dibutyltin diacetate, dibutyltin dilaurate, dioctyltin dilaurate, stannous octoate, dimethyltin diceneodecanoate, and dibutyltin bis(β-diketonate).

[0022] The present invention has but is not limited to the following beneficial effects:

[0023] 1. The product obtained by the present invention is easy to construct, has a fast curing speed, and the deep curing is not affected by the thickness of the glue. It does not corrode metals and electronic components, does not pollute stone materials, is green and environmentally friendly, and has no harm to the human body.

[0024] 2. The curing agent and resin of the product obtained by the invention are stored separately, which greatly improves the storage stability of the product.

[0025] 3. The product obtained by the present invention can form a stable substance on the outer surface under abnormally high temperature conditions, significantly improve the flame retardancy, and has good mildew resistance in a humid use environment.

[0026] 4. Non-polluting, meeting the pollution requirements of Part 20 of GB / T13477.20-2002 "Test Methods for Building Sealing Materials".

[0027] 5. The production process has low energy consumption, convenient construction, no three wastes, and no pollution to the environment.

[0028] Specific implementation methods

[0029] The specific implementation methods of the present invention are explained with the aid of examples. Except that the technology used for detection does not impose any form of limitation on the present invention, some schemes in the described embodiments belong to part of the embodiments of the invention. The embodiments obtained by ordinary technical operators in this field without creative results all belong to the protection scope of the present invention.

[0030] Example 1

[0031] This embodiment provides a two-component flame retardant and mildew-proof silicone sealant, including the following components AB in parts by weight:

[0032] 100 parts of α,ω-dihydroxypolydimethylsiloxane and 40 parts of filler are added to the planetary machine, and stirred for reaction for 30 minutes; 60 parts of flame retardant are added, and the mixture is stirred evenly and dispersed at high speed for 30 minutes; 0.06 parts of catalyst are added, and the mixture is stirred for reaction for 30 minutes to obtain component A; the filler is active nano calcium carbonate; the flame retardant is zinc carbonate; and the catalyst is dibutyltin dilaurate;

[0033] Preparation of alkoxy-terminated polydimethylsiloxane: 100 parts of hydroxy-terminated polydimethylsiloxane with a viscosity of 1500 mPa·s were placed in a container, and then 0.1 parts of methyltrimethoxysilane and 0.1 parts of vinyltrimethoxysilane were added, and nitrogen was introduced to stir and react for 30 minutes. 0.02 parts of cyclohexanone oxime, a blocking catalyst, was added, and the container was heated and kept at a constant temperature of 50°C. After reacting for 1 hour, the temperature was raised to 130°C, and low molecular weight was removed by vacuum, and the temperature was maintained for 120 minutes. The dimethoxy-terminated polydimethylsiloxane was obtained.

[0034] 100 parts of the prepared dimethoxy-terminated polydimethylsiloxane and 200 parts of the flame retardant were added to the planetary machine, stirred and reacted for 30 minutes; 0.2 parts of the mildew inhibitor were added; stirred and reacted for 30 minutes; 0.2 parts of the cross-linking agent were added, stirred and dispersed for 30 minutes, and 0.4 parts of the coupling agent were added, stirred and reacted for 30 minutes to obtain component B. The flame retardant was magnesium carbonate; the mildew inhibitor was a mixture of equal amounts of disulfide-2,2-bis(N-methylbenzamide) and 5-chloro-2-methyl-4-isothiazoline-3-one; the cross-linking agent was an equal mixture of methyltrimethoxysilane and methyl orthosilicate; the coupling agent was: 0.1 parts of γ-aminopropyltrimethyl(ethyl)oxysilane, 0.2 parts of N-βaminoethylγ-aminopropyltrimethyl(ethyl)oxysilane, and 0.1 parts of chloropropyltriethoxysilane.

[0035] Example 2

[0036] This embodiment provides a two-component flame retardant and mildew-proof silicone sealant, including the following components AB in parts by weight:

[0037] 100 parts of α,ω-dihydroxypolydimethylsiloxane and 50 parts of filler are added to the planetary machine, and stirred for reaction for 30 minutes; 60 parts of flame retardant are added, and the mixture is stirred evenly and dispersed at high speed for 30 minutes; 0.1 parts of catalyst are added, and the mixture is stirred for reaction for 30 minutes; component A is obtained; the filler is a mixture of equal amounts of quartz powder and talcum powder; the flame retardant is spherical aluminum hydroxide; the catalyst is dibutyltin dilaurate;

[0038] Preparation of alkoxy-terminated polydimethylsiloxane: 100 parts of hydroxy-terminated polydimethylsiloxane with a viscosity of 1500 mPa·s was placed in a container, and then 0.1 parts of methyltrimethoxysilane and 0.1 parts of vinyltrimethoxysilane were added, and nitrogen was introduced to stir and react for 30 minutes. 0.02 parts of potassium hydroxide, a blocking catalyst, was added, and the container was heated and kept at a constant temperature of 50°C. After reacting for 1 hour, the temperature was raised to 130°C, and low molecular weight was removed by vacuum, and the temperature was maintained for 120 minutes. The dimethoxy-terminated polydimethylsiloxane was obtained.

[0039] Add 100 parts of the prepared dimethoxy-terminated polydimethylsiloxane and 80 parts of the flame retardant into the planetary machine, stir and react for 30 minutes; add 0.2 parts of the mildew inhibitor; stir and react for 30 minutes; add 0.2 parts of the cross-linking agent, stir and disperse for 30 minutes, add 0.3 parts of the coupling agent, stir and react for 30 minutes, and prepare component B. The flame retardant is glass fiber; the mildew inhibitor is methyl 4-isothiazoline-3-one; the cross-linking agent is an equal mixture of methylvinyldimethoxysilane, polymethyltrimethoxysilane, and polymethyltriethoxysilane; the coupling agent is: 0.1 parts of γ-aminopropyltriethoxysilane, 0.2 parts of N-βaminoethylγ-aminopropyltrimethoxysilane, and 0.1 parts of chloropropyltriethoxysilane.

[0040] Example 3

[0041] This embodiment provides a two-component flame retardant and mildew-proof silicone sealant, including the following components AB in parts by weight:

[0042] 100 parts of α,ω-dihydroxypolydimethylsiloxane and 70 parts of filler are added to the planetary machine, and stirred for reaction for 30 minutes; 60 parts of flame retardant are added, and the mixture is stirred evenly and dispersed at high speed for 30 minutes; 0.06 parts of catalyst are added, and the mixture is stirred for reaction for 30 minutes to obtain component A; the filler is calcium silicate; the flame retardant is ammonium polyphosphate and diatomaceous earth; the catalyst is dioctyltin dilaurate;

[0043] Preparation of alkoxy-terminated polydimethylsiloxane: 100 parts of hydroxy-terminated polydimethylsiloxane with a viscosity of 1500 mPa·s are placed in a container, and then 0.1 parts of methyltrimethoxysilane and 0.1 parts of vinyltrimethoxysilane are added, and nitrogen is introduced to stir and react for 30 minutes. A capping catalyst is added, which is an equal mixture of potassium acetate and 0.02 parts of primary amine. The container is heated and kept at a constant temperature of 50°C. After reacting for 1 hour, the temperature is raised to 130°C, and vacuum is evacuated to remove low molecular weight and maintained for 120 minutes. The temperature is then lowered to obtain dimethoxy-terminated polydimethylsiloxane.

[0044] 100 parts of the prepared dimethoxy-terminated polydimethylsiloxane and 200 parts of the flame retardant are added to the planetary machine, stirred and reacted for 30 minutes; 0.2 parts of the mildew inhibitor are added; stirred and reacted for 30 minutes; 0.2 parts of the cross-linking agent are added, stirred and dispersed for 30 minutes, and 0.3 parts of the coupling agent are added, stirred and reacted for 30 minutes to obtain component B. The flame retardant is magnesium carbonate; the mildew inhibitor is a kasson mildew inhibitor or a quaternary ammonium salt mildew inhibitor; the cross-linking agent is an equal mixture of 1,2-bis(trimethoxysilyl) and 1,2-bis(triethoxysilyl); the coupling agent is: 0.1 parts of bis-[3-(trimethoxysilyl)-propyl]-ethylenediamine, 0.1 parts of bis-[3-(triethoxysilyl)-propyl]-ethylenediamine, and 0.1 parts of N-[3(trimethoxysilyl)-propyl]-n-butylamine.

[0045] Example 4

[0046] This embodiment provides a two-component flame retardant and mildew-proof silicone sealant, including the following components AB in parts by weight:

[0047] 100 parts of α,ω-dihydroxypolydimethylsiloxane and 70 parts of filler are added to the planetary machine, and stirred for reaction for 30 minutes; 60 parts of flame retardant are added, and the mixture is stirred evenly and dispersed at high speed for 30 minutes; 0.06 parts of catalyst are added, and the mixture is stirred for reaction for 30 minutes to obtain component A; the filler is active nano calcium carbonate; the flame retardant is zinc carbonate; and the catalyst is dibutyltin dilaurate;

[0048] Preparation of alkoxy-terminated polydimethylsiloxane: 100 parts of hydroxy-terminated polydimethylsiloxane with a viscosity of 1500 mPa·s were placed in a container, and then 0.1 parts of methyltrimethoxysilane and 0.1 parts of vinyltrimethoxysilane were added, and nitrogen was introduced to stir and react for 30 minutes. 0.02 parts of cyclohexanone oxime, a blocking catalyst, was added, and the container was heated and kept at a constant temperature of 50°C. After reacting for 1 hour, the temperature was raised to 130°C, and low molecular weight was removed by vacuum, and the temperature was maintained for 120 minutes. The dimethoxy-terminated polydimethylsiloxane was obtained.

[0049] 100 parts of the prepared dimethoxy-terminated polydimethylsiloxane and 200 parts of the flame retardant were added to the planetary machine, stirred and reacted for 30 minutes; 0.2 parts of the mildew inhibitor were added; stirred and reacted for 30 minutes; 0.2 parts of the cross-linking agent were added, stirred and dispersed for 30 minutes, and 0.2 parts of the coupling agent were added, stirred and reacted for 30 minutes to obtain component B. The flame retardant was magnesium carbonate; the mildew inhibitor was a mixture of equal amounts of disulfide-2,2-bis(N-methylbenzamide) and 5-chloro-2-methyl-4-isothiazoline-3-one; the cross-linking agent was an equal amount of methyltrimethoxysilane and methyl orthosilicate; the coupling agent was: 0.1 parts of γ-(2,3-epoxypropoxy)propyltrimethoxysilane and 0.1 parts of γ-(2,3-epoxypropoxy)propyltriethoxysilane.

[0050] Comparative Example 1: The preparation of a 1:1 two-component mildew-proof and flame-retardant sealant in this comparative example is the same as that in Example 2, except that component B uses α,ω-dihydroxy polydimethylsiloxane instead of dimethoxy-terminated polydimethylsiloxane.

[0051] Comparative Example 2: The method of preparing a 1:1 two-component mildew-proof and flame-retardant sealant in this comparative example is substantially the same as that in Example 3, except that no mildew-proofing agent is added.

[0052] Comparative Example 3: The method of preparing a 1:1 two-component mildew-proof and flame-retardant sealant in this comparative example is substantially the same as that in Example 4, except that calcium carbonate is used instead of the combustion aid.

[0053] Example 5

[0054] Product performance testing

[0055] With reference to GB / T 528-2009 "Determination of tensile stress-strain properties of vulcanized rubber or thermoplastic rubber", GB13477-2002 "Test methods for building sealing materials"; GB / -T 2408-2008 "Determination of combustion performance of plastics"; GB / T1741-2020 "Determination of mildew resistance of paint films"; GB 4706.1072012 "Particular requirements for safety of integrated kitchen appliances for household and similar electrical appliances", the products of the embodiment and the control group were tested, and the product performance is shown in the following table, specifically:

[0056]

Claims

1. A method for preparing alkoxy-terminated polydimethylsiloxane, characterized in that The steps include: (1) placing α,ω-dihydroxy polydimethylsiloxane in a container at room temperature, adding a capping agent and mixing for 30-90 minutes, and introducing nitrogen protection throughout the process; the capping agent is a mixture of methyltrimethoxysilane and vinyltrimethoxysilane; (2) After adding the end-capping catalyst, the temperature is kept at 50-80° C. for reaction for 20-60 minutes. After the reaction is completed, the temperature is raised to 120-140° C. for vacuum removal of low molecular weight substances for 60-120 minutes, and the temperature is lowered to obtain alkoxy-end-capped polydimethylsiloxane.

2. The preparation method according to claim 1, characterized in that: The mass ratio of the α,ω-dihydroxy polydimethylsiloxane, the end-capping agent and the catalyst is 1:(0.02-0.1):(0.02-0.1); the α,ω-dihydroxy polydimethylsiloxane is a hydroxyl-terminated short-chain linear polysiloxane; the vacuum degree when removing low molecular weight substances and water in the system in step (2) is -0.08 to -0.1 MPa.

3. The preparation method according to claim 1, characterized in that: The blocking catalyst is one or two of cyclohexanone oxime, potassium hydroxide, potassium acetate and primary amine.

4. A two-component flame retardant and mildew-proof silicone sealant, characterized in that It includes the following components by weight: Component A: Component B:

5. The two-component flame retardant and mildew-proof silicone sealant according to claim 4, characterized in that: The filler is one or more of heavy calcium carbonate, activated calcium carbonate, quartz powder, talc powder, mica powder, kaolin, wollastonite, calcium silicate, barium sulfate, magnesium silicate, aluminum hydroxide, magnesium hydroxide, montmorillonite, aluminum oxide, magnesium oxide, zinc oxide, aluminum nitride, and boron nitride.

6. The two-component flame retardant and mildew-proof silicone sealant according to claim 4, characterized in that: The crosslinking agent includes: at least one of methyltrimethoxysilane, methyl orthosilicate, propyltrimethoxysilane, polymethyltriethoxysilane propyl orthosilicate, vinyltrimethoxysilane, methyltriethylsilane, methylpropyldimethoxysilane, methylpropyldiethoxysilane, vinyltriethoxysilane, propyltriethoxysilane, methylvinyldimethoxysilane, polymethyltrimethoxysilane, polymethyltriethoxysilane, polypropyltrimethoxysilane, 1,2-bis(trimethoxysilyl) and 1,2-bis(triethoxysilyl).

7. The two-component flame retardant and mildew proof silicone sealant according to claim 4, characterized in that: The flame retardant is at least one of spherical aluminum hydroxide, spherical magnesium hydroxide, nano zinc carbonate, magnesium carbonate, zinc borate, montmorillonite, glass fiber, antimony trioxide, ammonium polyphosphate and diatomaceous earth.

8. The two-component flame retardant and mildew proof silicone sealant as claimed in claim 4, characterized in that: The coupling agent includes chloropropyl triethoxysilane, isocyanate propyl trimethoxysilane, γ-aminopropyl trimethoxysilane, γ-aminopropyl triethoxysilane, N-(β-aminoethyl)-γ-aminopropyl triethoxysilane, bis-[3-(trimethoxysilyl)-propyl]-ethylenediamine, bis-[3-(triethoxysilyl)-propyl]-ethylenediamine, N-[3(trimethoxysilyl)-propyl]-n-butylamine, N,N-dimethyl-3-aminopropyl trimethoxysilane, N-n-butyl-3-aminopropyl triethoxysilane, At least one of oxysilane, hexamethyldisilazane, γ-(2,3-epoxypropyloxy)propyltrimethoxysilane, γ-(2,3-epoxypropyloxy)propyltriethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltri(3-oxysilane), 2-(3,4-epoxycyclohexyl)ethyltriethoxysilane, 2-cyanoethyltriethoxysilane, ureidopropyltriethoxysilane, 3-methacryloxypropyltrimethoxysilane, isocyanatepropyltriethoxysilane and vinyltri(2-methoxyethoxy)silane.

9. The two-component flame retardant and mildew-proof silicone sealant according to claim 4, characterized in that: The mildew preventer is at least one of disulfide-2,2-bis(N-methylbenzamide), 5-chloro-2methyl-4-isothiazoline-3-one, methyl 4-isothiazoline-3-one, 1,2-benzisothiazolin-3-one, n-octyl 4-isothiazoline-3-one, and dimethyl fumarate.

10. The two-component flame retardant and mildew-proof silicone sealant according to claim 4, characterized in that: The catalyst is at least one of dibutyltin diacetate, dibutyltin dilaurate, dioctyltin dilaurate, stannous octoate, dimethyltin diceneodecanoate, and dibutyltin bis(β-diketonate).

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