Transparent deacidification type long-acting mildew-proof silicone sealant

Abstract

The transparent deacidification type long-acting mildew-proof silicone sealant is prepared from the following components in parts by mass: 80 to 110 parts of basic polymer, 15 to 25 parts of plasticizer, 6 to 9 parts of cross-linking agent, 10 to 15 parts of filler, 0.05 to 0.2 part of mildew preventive, 1 to 2 parts of tackifier and 0.05 to 0.2 part of catalyst, the cross-linking agent is any one or a combination of more of methyl triacetoxysilane, ethyl triacetoxysilane, propyl triacetoxysilane, methyl tris (2-ethyl acetoxygroup) silane or methyl tris (benzoyloxy) silane; and the cross-linking agent is any one or a combination of more of methyl triacetoxysilane, ethyl triacetoxysilane, propyl triacetoxysilane, methyl tris (benzoyloxy) silane. Through the design of the sealant formula, the sealant with excellent comprehensive performance can be obtained, the curing speed is high, the bonding performance is good, long-acting mildew prevention is achieved, and the use scene of the sealant is widened.

Description

Technical Field

[0001] The present application relates to the field of sealants, and in particular to a transparent deacidified long-lasting mildew-proof silicone sealant. Background Art

[0002] Single-component room temperature vulcanized silicone rubber (RTV-1), commonly known as silicone sealant, is a paste made by mixing α,ω-dihydroxy polydimethylsiloxane as the base polymer with crosslinking agent, plasticizer, filler, coupling agent and catalyst under vacuum. It solidifies into elastic silicone rubber by condensation reaction with water in the air at room temperature. Due to its advantages of fast curing speed, good adhesion and high strength, it is widely used in construction engineering and interior decoration industry.

[0003] However, in warm and humid environments, such as kitchens and bathrooms, bacteria, mold and other microorganisms are very easy to multiply, which can easily cause the sealant to become moldy, blackened, or even fail to bond. These microorganisms not only seriously affect the appearance and use, but also pose a potential threat to people's health. Therefore, the development of mildew-proof sealants has received more and more attention.

[0004] In order to solve the problem of sealant becoming moldy and black in a hot and humid environment, Chinese invention patent CN116606626A discloses a mildew-proof silicone sealant and its preparation method, using sodium deoxycholate to achieve mildew and antibacterial effects. However, sodium deoxycholate is easily soluble in water and easily absorbs moisture in the air, resulting in a limited mildew-proof life of the sealant. After being used in a humid environment for a period of time, the sealant will still become moldy, and the long-term mildew-proof effect cannot be achieved.

[0005] Chinese invention patent CN110684506A relates to an anti-mildew glue and its preparation method. By reasonably mixing the raw material components of silane-modified resin, polypropylene glycol, calcium carbonate, vinyl trimethoxy silane, aluminum hydroxide, stabilizer, silica, coupling agent and catalyst, the anti-mildew glue finally prepared has a short curing time, high bonding strength and excellent anti-mildew effect, but the storage stability of the glue is poor.

[0006] It is necessary to provide a sealant with good stability, not easy to fail, good bonding effect and mildew resistance effect. Summary of the invention

[0007] The purpose of the present application is to provide a sealant with fast curing speed, good mechanical properties and long-lasting mildew-proof effect.

[0008] In order to achieve the above purpose, the technical solution adopted in the present application is: to provide a transparent deacidified long-lasting mildew-proof silicone sealant, comprising the following components, by mass: 80 to 110 parts of base polymer, 15 to 25 parts of plasticizer, 6 to 9 parts of cross-linking agent, 10 to 15 parts of filler, 0.05 to 0.2 parts of mildewproof agent, 1 to 2 parts of tackifier and 0.05 to 0.2 parts of catalyst, wherein the cross-linking agent is any one of methyltriacetoxysilane, ethyltriacetoxysilane, propyltriacetoxysilane, methyltri(2-ethylacetoxy)silane or methyltri(benzoyloxy)silane, or a combination of more than one thereof.

[0009] As a preference, the crosslinking agent is a mixture of methyltriacetoxysilane, ethyltriacetoxysilane and propyltriacetoxysilane.

[0010] As another preference, the cross-linking agent is a mixture of methyl triacetoxysilane, ethyl triacetoxysilane and propyl triacetoxysilane in a mass ratio of (1:1:1) to (4:2:1).

[0011] As another preference, the base polymer is α,ω-hydroxy-terminated polydimethylsiloxane, and its viscosity is 1500 to 300000 mPa·s.

[0012] As another preference, the base polymer comprises a low-viscosity polymer and a high-viscosity polymer, the viscosity of the low-viscosity polymer is less than or equal to 50,000 mPa·s, and the viscosity of the high-viscosity polymer is greater than 50,000 mPa·s.

[0013] As another preference, the mass ratio of the low-viscosity polymer to the high-viscosity polymer is (4:5) to (5:4).

[0014] As another preference, the filler is fumed silica, the plasticizer is non-reactive polysiloxane, and the tackifier can be one or a combination of di-tert-butyl diacetoxysilane, tris(1,3,5-trimethoxysilyl)propyl polyisocyanate, alkoxyacyloxysilane, and glycidyloxypropyl trimethoxysilane.

[0015] As another preference, the mildew inhibitor is an isothiazolinone compound.

[0016] As another preferred embodiment, the mildew inhibitor is 2-butyl-1,2-benzisothiazolin-3-one.

[0017] The present application also provides a method for preparing a transparent deacidified long-lasting mildew-proof silicone sealant, comprising the following preparation steps: S1: stirring and mixing the base polymer and the plasticizer in a vacuum to obtain a base material; S2: adding the cross-linking agent and the filler in sequence, and stirring and mixing them in a vacuum; S3: adding the mildew inhibitor, the tackifier and the catalyst in sequence under an inert gas atmosphere, and mixing them evenly under vacuum stirring to obtain a finished product.

[0018] Compared with the prior art, the beneficial effects of this application are:

[0019] (1) The present application can obtain a sealant with excellent comprehensive performance through the design of the sealant formula, which has a fast curing speed, good bonding performance, and long-term mildew resistance, thereby broadening the application scenarios of the sealant;

[0020] (2) The sealant of the present application is compounded with methyl triacetoxysilane, ethyl triacetoxysilane and propyl triacetoxysilane, which can accelerate the curing speed of the sealant, form a stable and dense cross-linked network, and further reduce mold;

[0021] (3) The preparation method of the transparent deacidified long-lasting mildew-proof silicone sealant of the present application is simple, the raw materials are low-cost, the storage is stable, and it has good practicality. DETAILED DESCRIPTION

[0022] Below, the present application is further described in conjunction with specific implementation methods. It should be noted that, under the premise of no conflict, the various embodiments or technical features described below can be arbitrarily combined to form new embodiments.

[0023] The terms "including" and "having" and any variations thereof in the specification and claims of this application are intended to cover non-exclusive inclusions. For example, a process, method, system, product or apparatus comprising a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to these processes, methods, products or apparatuses.

[0024] The present application provides a transparent deacidified long-lasting mildew-proof silicone sealant, comprising the following components, calculated by mass: 80 to 110 parts of a base polymer, 15 to 25 parts of a plasticizer, 6 to 9 parts of a cross-linking agent, 10 to 15 parts of a filler, 0.05 to 0.2 parts of a mildew-proofing agent, 1 to 2 parts of a tackifier and 0.05 to 0.2 parts of a catalyst.

[0025] The transparent deacidified long-lasting mildew-proof silicone sealant of the present application has the characteristics of simple preparation process, fast curing speed, good adhesion, long-lasting mildew-proof, and is suitable for long-term stable storage, reducing economic costs.

[0026] In some embodiments, the base polymer is α,ω-hydroxy-terminated polydimethylsiloxane, and its viscosity is 1500-300000 mPa·s. The molecular chain structure of α,ω-hydroxy-terminated polydimethylsiloxane can give the sealant good elasticity and flexibility.

[0027] In some preferred embodiments, the base polymer includes two α,ω-terminated hydroxyl polydimethylsiloxanes of different viscosities, specifically a low-viscosity polymer with a viscosity of less than or equal to 50,000 mPa·s and a high-viscosity polymer with a viscosity of more than 50,000 mPa·s.

[0028] In a further preferred embodiment, the mass ratio of the low viscosity polymer to the high viscosity polymer is (4:5) to (5:4). When the viscosity of the base polymer is too low, the sealant will have high hardness and poor elasticity after vulcanization, and too high viscosity will result in poor processing performance of the sealant. Using a mixture of high and low viscosity base polymers is conducive to achieving the best comprehensive performance of the sealant.

[0029] The plasticizer is a non-reactive polysiloxane, and the preferred plasticizer is methyl-terminated polydimethylsiloxane. Methyl-terminated polydimethylsiloxane has good compatibility with the base polymer, and its proportion in the formula can be adjusted to achieve a wide range of product viscosity, hardness, elongation and other properties to meet the personalized needs of different products.

[0030] In addition, methyl-terminated polydimethylsiloxane has excellent thermal stability and chemical stability, can maintain stable performance over a wide temperature range, is not prone to decomposition or adverse reactions with other substances, and effectively extends the service life of the sealant.

[0031] In some preferred embodiments, the viscosity of the plasticizer is 100-1000 mPa·s, preferably in the range of 150-350 mPa·s.

[0032] The crosslinking agent of the present application is any one of methyltriacetoxysilane, ethyltriacetoxysilane, propyltriacetoxysilane, methyltri(2-ethylacetoxy)silane or methyltri(benzoyloxy)silane, or a combination of multiple thereof.

[0033] In a preferred embodiment, the crosslinking agent of the present application is a mixture of methyl triacetoxysilane, ethyl triacetoxysilane and propyl triacetoxysilane. The compound crosslinking agent can accelerate the curing speed of the sealant and form a stable and dense crosslinking network to resist the invasion of mold, reduce the phenomenon of mold, and achieve physical mildew prevention.

[0034] In a further preferred embodiment, the crosslinking agent is a mixture of methyltriacetoxysilane, ethyltriacetoxysilane and propyltriacetoxysilane in a mass ratio of (1:1:1) to (4:2:1).

[0035] The filler is fumed silica, which has a porous structure and a high specific surface area. Adding it to the base polymer can play a reinforcing and thixotropic role, improve the tensile strength of the sealant, prevent the colloid from sagging, and enhance the wear resistance and tear resistance of the sealant, making it more durable during use.

[0036] In addition, the use of silica as a filler can maintain the transparency of acid sealants, effectively reduce product costs, and adjust the hardness and density of the product.

[0037] The mildew preventer is an isothiazolinone compound, and the preferred mildew preventer is 2-butyl-1,2-benzisothiazolin-3-one (BBIT). The present application prefers BBIT as a chemical mildew preventer, which has a broad-spectrum antibacterial property and can effectively inhibit the growth of Gram-positive and Gram-negative bacteria. It also has a good inhibitory effect on mold, yeast and algae, so that BBIT can provide comprehensive protection against mold in a variety of application scenarios.

[0038] BBIT's sterilization method is non-specific, bacteria cannot develop resistance, and it reduces bacterial mutation and antibacterial phenomena, thus improving the long-term antibacterial properties of the sealant.

[0039] BBIT has high antibacterial properties and strong stability. It does not contain volatile organic compounds, will not accumulate in organisms, and will not cause continuous pollution to the environment. It is a highly effective mildew preventer.

[0040] The tackifier can be one or more of di-tert-butyl diacetoxysilane, tris(1,3,5-trimethoxysilyl)propyl polyisocyanate, alkoxyacyloxysilane, and glycidyloxypropyl trimethoxysilane, preferably any one or more of di-tert-butyl diacetoxysilane and tris(1,3,5-trimethoxysilyl)propyl polyisocyanate.

[0041] Tackifiers play an important role in sealants. They can act as a "molecular bridge" to connect inorganic materials and organic materials, connecting two materials with different properties, enhancing the bonding properties of sealants, and enabling the sealants to better adhere to the surface of the substrate during use, thereby enhancing the sealing effect.

[0042] The catalyst is any one of dibutyltin dilaurate, dibutyltin diacetate, dioctyltin dilaurate or stannous octoate or a combination of more than one thereof.

[0043] The mildew-proof sealant of the present application is a transparent sealant, which has the advantages of being beautiful, fast curing speed, and good bonding performance, and can achieve the effects of long-term mildew-proofing and stable transportation and storage performance.

[0044] The present application also provides a method for preparing a transparent deacidified long-lasting mildew-proof silicone sealant, according to the following steps:

[0045] S1: stirring and mixing a base polymer and a plasticizer in a vacuum to obtain a base material;

[0046] S2: adding the crosslinking agent and the filler in sequence, and stirring and mixing them in a vacuum;

[0047] S3: Add the mildew inhibitor, tackifier and catalyst in sequence under an inert gas atmosphere, and stir and mix them evenly under vacuum to obtain a finished product.

[0048] The preparation process of the mildew-proof sealant of the present application is simple, the various raw materials used are stable in nature, widely available, easy to obtain, and have low preparation cost.

[0049] Example 1

[0050] A method for preparing a transparent deacidified long-lasting mildew-proof silicone sealant is prepared by following the steps below:

[0051] S1: 100 parts by mass of a base polymer and 15 parts by mass of a plasticizer are placed in a planetary mixer and stirred for 30 minutes under a vacuum degree greater than 0.09 MPa to obtain a base material;

[0052] S2: Add 6 parts by weight of cross-linking agent into the planetary machine and stir for 30 minutes under the condition of vacuum degree greater than 0.09 MPa; add 10 parts by weight of filler into the planetary machine in batches and stir, and turn on the vacuum after all the filler is consumed, and stir for 30 minutes under the condition of vacuum degree greater than 0.09 MPa;

[0053] S3: Under the protection of nitrogen, 0.05 parts by mass of mildew inhibitor, 1 part by mass of tackifier and 0.05 parts by mass of catalyst were added at a time, and the finished product was obtained after stirring for 30 minutes under the condition of vacuum degree greater than 0.09 MPa.

[0054] The base polymer includes a low-viscosity polymer and a high-viscosity polymer in a mass ratio of 1:1, the viscosity of the low-viscosity polymer is 20000mPa·s, and the viscosity of the high-viscosity polymer is 80000mPa·s; the plasticizer is methyl-terminated polydimethylsiloxane with a viscosity of 350mPa·s; the crosslinker is a mixture of methyltriacetoxysilane, ethyltriacetoxysilane and propyltriacetoxysilane in a mass ratio of 1:1:1; the filler is fumed silica with a specific surface area of ​​180m 2 / g; the mildew inhibitor is 2-butyl-1,2-benzisothiazolin-3-one; the tackifier is di-tert-butyl diacetoxysilane; and the catalyst is dibutyltin diacetate.

[0055] Example 2

[0056] The mass ratio of the low-viscosity polymer to the high-viscosity polymer in the base polymer was adjusted to 4:5, and the other preparation steps were consistent with the preparation steps in Example 1.

[0057] Example 3

[0058] The mass ratio of the low viscosity polymer to the high viscosity polymer in the base polymer was adjusted to 5:4, and the other preparation steps were consistent with the preparation steps in Example 1.

[0059] Example 4

[0060] The mass ratio of methyltriacetoxysilane, ethyltriacetoxysilane and propyltriacetoxysilane in the crosslinking agent was adjusted to 2:2:1, and the other preparation steps were consistent with the preparation steps in Example 3.

[0061] Example 5

[0062] The mass ratio of methyltriacetoxysilane, ethyltriacetoxysilane and propyltriacetoxysilane in the crosslinking agent was adjusted to 4:2:1, and the other preparation steps were consistent with the preparation steps in Example 3.

[0063] Example 6

[0064] The addition amount of the mildew inhibitor was adjusted to 0.1 parts by mass, and the other preparation steps were consistent with those in Example 5.

[0065] Comparative Example 1

[0066] The cross-linking agent was replaced with methyltriacetoxysilane, and the other preparation steps were consistent with those in Example 3.

[0067] Comparative Example 2

[0068] The cross-linking agent was replaced with ethyltriacetoxysilane, and the other preparation steps were consistent with those in Example 3.

[0069] Comparative Example 3

[0070] The cross-linking agent was replaced with propyltriacetoxysilane, and the other preparation steps were consistent with those in Example 3.

[0071] Comparative Example 4

[0072] No mildewcide was added, and other preparation steps were consistent with those in Example 3.

[0073] Comparative Example 5

[0074] In the base polymer, low-viscosity polymers with a viscosity of 20000 mPa·s were used, and the other preparation steps were consistent with the preparation steps in Example 3.

[0075] Comparative Example 6

[0076] Among the base polymers, high-viscosity polymers with a viscosity of 80,000 mPa·s were used, and the other preparation steps were consistent with the preparation steps in Example 3.

[0077] Performance Testing

[0078] 1. Surface drying time: Tested according to the requirements of GB / T 13477.5-2017;

[0079] 2. Extrudability: Tested according to GB / T 13477.4-2017, the air source pressure is 0.3±0.01Mpa, and the nozzle is made of 3mm HDPE material;

[0080] 3. Curing depth: Tested according to GB / T 32369-2005 curing cup method;

[0081] 4. Adhesion test: Test according to GB / T 16776-2005 Appendix D Method B: Hand-pull test method (non-finished product destructive method), the substrate is anodized aluminum and float glass;

[0082] 5. The tensile strength and elongation at break are tested according to GB / T 528-2009;

[0083] 6. Hardness: Sample preparation and testing shall be carried out according to GB / T 531.1-2008;

[0084] 7. Initial mildew resistance level: Sample preparation and testing in accordance with GB / T1741-2020

[0085] 8. Anti-mildew grade after long-term use: To simulate the anti-mildew performance of the sealant after long-term use, the sealant was made into a 50mm*50mm*2mm sample. After curing under standard conditions for 7 days, it was immersed in water at 60±2℃ for 360h and 720h, and then taken out and cured under standard conditions for 48h. The anti-mildew grade of the sample was tested in accordance with GB / T 1741-2020.

[0086] 9. Storage stability test: subject the glue sample to accelerated aging for 14 days at 70°C and 70% RH, and compare the curing and bonding conditions before and after aging to verify the storage stability of the sealant.

[0087] The sealants prepared in the embodiments and comparative examples of the present application were subjected to the above-mentioned performance tests, and the performance test results are recorded in the following Table 1.

[0088] Table 1 Performance test results of each embodiment and each comparative example

[0089] The mold-proof sealant of the present application is a sealant product with superior comprehensive performance through the design of the formula. The sealant has excellent adhesion, can achieve firm adhesion with a variety of substrates, and maintain a long-term stable bonding effect. At the same time, the sealant has high mechanical strength and can withstand large external forces, meeting the use requirements in various complex environments.

[0090] In addition, the sealant has a fast curing speed, which greatly shortens the construction period and improves work efficiency. The most outstanding feature is its long-term mildew-proof property, which can effectively inhibit the growth and reproduction of mildew. Even in a humid, high-temperature environment that is prone to mildew, it can maintain a long-term mildew-proof effect, providing users with long-lasting and reliable sealing and protection.

[0091] By analyzing the performance test results of Example 3 and Comparative Examples 1 to 3, the present application uses methyltriacetoxysilane, ethyltriacetoxysilane and propyltriacetoxysilane as a cross-linking agent to improve the curing speed and stability of the sealant.

[0092] Analyzing the performance test results of Example 3 and Comparative Example 4, the present application adds a mildew inhibitor to the sealant, so that the sealant can inhibit the growth and reproduction of mold, and broaden the application scenarios of the sealant. The mildew-proof sealant of the present application has a good initial mildew-proof effect, and can still obtain a good mildew-proof effect after curing and long-term use.

[0093] Analysis of the performance test results of Example 3 and Comparative Examples 5 to 6 shows that the use of base polymers with different viscosities can further optimize the comprehensive performance of the sealant.

[0094] In summary, the transparent deacidified long-lasting mildew-proof silicone sealant of the present application has good mildew-proof effect, fast curing speed, good mechanical strength, can be used in a variety of scenarios, has a simple preparation method and low cost, and has certain practicality.

[0095] The above describes the basic principles, main features and advantages of the present application. Those skilled in the art should understand that the present application is not limited by the above embodiments, and the above embodiments and the specification only describe the principles of the present application. The present application may have various changes and improvements without departing from the spirit and scope of the present application, and these changes and improvements fall within the scope of the present application for which protection is sought. The scope of protection claimed by the present application is defined by the attached claims and their equivalents.

Claims

1. A transparent deacidified long-lasting mildew-proof silicone sealant, characterized in that: The invention comprises the following components, in parts by mass: 80 to 110 parts of a base polymer, 15 to 25 parts of a plasticizer, 6 to 9 parts of a cross-linking agent, 10 to 15 parts of a filler, 0.05 to 0.2 parts of a mildew preventer, 1 to 2 parts of a tackifier and 0.05 to 0.2 parts of a catalyst, wherein the cross-linking agent is any one of methyltriacetoxysilane, ethyltriacetoxysilane, propyltriacetoxysilane, methyltri(2-ethylacetoxy)silane or methyltri(benzoyloxy)silane, or a combination of more than one thereof.

2. A transparent deacidified long-lasting mildew-proof silicone sealant as claimed in claim 1, characterized in that: The crosslinking agent is a mixture of methyltriacetoxysilane, ethyltriacetoxysilane and propyltriacetoxysilane.

3. A transparent deacidified long-lasting mildew-proof silicone sealant as claimed in claim 2, characterized in that: The crosslinking agent is a mixture of methyl triacetoxysilane, ethyl triacetoxysilane and propyl triacetoxysilane in a mass ratio of (1:1:1) to (4:2:1).

4. A transparent deacidified long-lasting mildew-proof silicone sealant as claimed in claim 1, characterized in that: The base polymer is α,ω-terminated hydroxyl polydimethylsiloxane, and its viscosity is 1500-300000 mPa·s.

5. A transparent deacidified long-lasting mildew-proof silicone sealant as claimed in claim 4, characterized in that: The base polymer includes a low-viscosity polymer and a high-viscosity polymer, the viscosity of the low-viscosity polymer is less than or equal to 50,000 mPa·s, and the viscosity of the high-viscosity polymer is greater than 50,000 mPa·s.

6. A transparent deacidified long-lasting mildew-proof silicone sealant as claimed in claim 5, characterized in that: The mass ratio of the low-viscosity polymer to the high-viscosity polymer is (4:5) to (5:4).

7. A transparent deacidified long-lasting mildew-proof silicone sealant as claimed in claim 1, characterized in that: The filler is fumed silica, the plasticizer is non-reactive polysiloxane, and the tackifier can be one or a combination of di-tert-butyl diacetoxysilane, tris(1,3,5-trimethoxysilyl)propyl polyisocyanate, alkoxyacyloxysilane, and glycidyloxypropyl trimethoxysilane.

8. A transparent deacidified long-lasting mildew-proof silicone sealant as claimed in claim 1, characterized in that: The mildew inhibitor is an isothiazolinone compound.

9. A transparent deacidified long-lasting mildew-proof silicone sealant as claimed in claim 8, characterized in that: The mildew preventer is 2-butyl-1,2-benzisothiazolin-3-one.

10. A method for preparing a transparent deacidified long-lasting mildew-proof silicone sealant as claimed in any one of claims 1 to 9, characterized in that: The method comprises the following preparation steps: S1: stirring and mixing the base polymer and the plasticizer in a vacuum to obtain a base material; S2: adding the cross-linking agent and the filler in sequence, and stirring and mixing them in a vacuum; S3: adding the mildew inhibitor, the tackifier and the catalyst in sequence under an inert gas atmosphere, and mixing them evenly under vacuum stirring to obtain a finished product.

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