An antibacterial and mildew-proof colorant for silicone rubber and its preparation method

Abstract

The present invention belongs to the technical field of additives for silicone rubber, and particularly relates to an antibacterial and mildew-proof colorant for silicone sealant and a preparation method thereof. The preparation method comprises the following steps: (1) adding inorganic color powder, silicate ester and dimethyloctadecyl [3-(trimethoxysilyl)propyl] ammonium chloride into a solvent, stirring and mixing evenly, heating to 40-80 °C, then dropping ammonia water and stirring for reaction, and performing vacuum drying after the reaction is completed to obtain quaternary ammonium salt-modified TQ silicone resin-coated inorganic color powder; (2) mixing and dispersing the obtained quaternary ammonium salt-modified TQ silicone resin-coated inorganic color powder with hydroxy silicone oil evenly to obtain an antibacterial and mildew-proof colorant for silicone sealant. The present invention uses quaternary ammonium salt-modified TQ silicone resin to coat and modify inorganic color powder, which can significantly improve the coloring effect and endow silicone sealant with obvious antibacterial and mildew-proof properties.

Description

Technical Field

[0001] The present invention belongs to the technical field of additives for silicone rubber, and particularly relates to an antibacterial and mildew-proof colorant for silicone sealant and a preparation method thereof. Background Art

[0002] Silicone sealant, also known as silicone rubber, is widely used in the fields of bonding, caulking, jointing, sealing, waterproofing, and reinforcement in construction engineering and decoration. Silicone sealant is colorless by itself. To endow silicone sealant with different colors, color powder needs to be added to improve its color richness. However, due to the strong hydrophobic and oleophobic properties of silicone sealant, the dispersion effect of pure color powder in silicone sealant is poor, and it is difficult for the color powder to be wetted and dispersed by the silicone sealant base material, resulting in the aggregation of color powder and the decrease of coloring strength.

[0003] To improve the dispersion effect of color powder in the silicone sealant base material, it is generally common in the industry to first mix the color powder with an organosilicon plasticizer to prepare a colorant to achieve the effect of pre-wetting the color powder. For example, Patent CN 114149767 A discloses a weather and temperature resistant inorganic silicone sealant color paste, which includes the following components in parts by mass: 40-50 parts of silicone resin, 40-60 parts of composite inorganic pigment, 10-15 parts of plasticizer, 5-7 parts of wetting agent, 2-5 parts of dispersant, and 0.5-1 part of silane coupling agent; the composite inorganic pigment includes one or more of titanium chromium pigment, titanium nickel pigment, and cobalt-based pigment; the silicone resin includes dihydroxypolysiloxane and / or dodecamethylcyclohexasiloxane. Through dihydroxypolysiloxane and / or dodecamethylcyclohexasiloxane, combined with silane coupling agent, the dispersion uniformity of the composite inorganic pigment is improved. However, the plasticizer used is non-reactive polydimethylsiloxane, which has a weak binding force with the color paste, and color powder aggregation still cannot be avoided during the mixing process with the silicone sealant base material; at the same time, low-viscosity polydimethylsiloxane has an adverse effect on the strength of silicone sealant.

[0004] In addition, when silicone sealant is used in a humid environment, it is easily invaded by microorganisms, resulting in mildew, discoloration, and blackening. To endow silicone sealant with antibacterial and mildew-proof properties, it is generally common to add inorganic or organic antibacterial and mildew-proof agents to achieve the corresponding antibacterial and mildew-proof effects. However, the addition of antibacterial and mildew-proof agents also needs to consider the dispersion effect in the silicone sealant system and the impact on the mechanical strength of silicone sealant. Summary of the Invention

[0005] Aiming at the above-mentioned drawbacks and deficiencies of the prior art, the primary object of the present invention is to provide a preparation method of an antibacterial and mildew-proof colorant for silicone sealant.

[0006] Another object of the present invention is to provide an antibacterial and mildew-proof colorant prepared by the above method.

[0007] Another object of the present invention is to provide the application of the above antibacterial and mildew-proof colorant in the alcohol-free silicone sealant.

[0008] The object of the present invention is achieved by the following technical solutions:

[0009] A preparation method of an antibacterial and mildew-proof colorant for silicone sealant, comprising the following preparation steps:

[0010] (1) Add inorganic color powder, silicate ester and dimethyloctadecyl [3-(trimethoxysilyl)propyl] ammonium chloride to a solvent, stir and mix evenly, heat up to 40-80 °C, then dropwise add ammonia water and stir to react. After the reaction is completed, vacuum dry to obtain quaternary ammonium salt modified TQ silicone resin coated inorganic color powder;

[0011] (2) Mix and disperse the obtained quaternary ammonium salt modified TQ silicone resin coated inorganic color powder with hydroxy silicone oil evenly to obtain an antibacterial and mildew-proof colorant for silicone sealant.

[0012] Preferably, the inorganic color powder includes carbon powder, titanium dioxide powder, zinc oxide powder or iron oxide series color powder, etc.

[0013] Preferably, the silicate ester is methyl orthosilicate, ethyl orthosilicate, propyl orthosilicate or butyl orthosilicate.

[0014] Preferably, the mass ratio of the added inorganic color powder, silicate ester and dimethyloctadecyl [3-(trimethoxysilyl)propyl] ammonium chloride is 100:10-30:10-30.

[0015] Preferably, the solvent is methanol, ethanol or propanol.

[0016] Preferably, the mass concentration of the ammonia water is 25%-28%, and the addition amount of the ammonia water is 10%-50% of the total mass of the silicate ester and dimethyloctadecyl [3-(trimethoxysilyl)propyl] ammonium chloride.

[0017] Preferably, the hydroxyl content of the hydroxy silicone oil is 0.5%-10% (wt.%), and the viscosity is 15-200 mm 2 / s (25 °C).

[0018] Preferably, the mass ratio of the quaternary ammonium salt modified TQ silicone resin coated inorganic color powder to the hydroxy silicone oil is 100:50-200.

[0019] More preferably, the method for mixing and dispersing the quaternary ammonium salt modified TQ silicone resin coated inorganic color powder with the hydroxy silicone oil evenly is: adding the quaternary ammonium salt modified TQ silicone resin coated inorganic color powder and the hydroxy silicone oil to methylcyclosiloxane, heating and stirring for homogenization treatment, and then vacuum removing the methylcyclosiloxane to obtain an antibacterial and mildew-proof colorant for silicone sealant.

[0020] Preferably, the methylcyclosiloxane is hexamethylcyclotrisiloxane (D3), octamethylcyclotetrasiloxane (D4), decamethylcyclopentasiloxane (D5) or dimethylsiloxane mixed cyclic oligomers (DMC); the addition amount of the methylcyclosiloxane is 50% - 200% of the mass of the hydroxyl silicone oil; the temperature for the heat stirring for homogenization treatment is 60 - 100 °C, and the time is 1 - 4 h.

[0021] An antibacterial and mildew-proof colorant for silicone rubber is prepared by the above method.

[0022] Application of the above antibacterial and mildew-proof colorant in the alcohol-free silicone rubber.

[0023] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0024] (1) In the present invention, the inorganic color powder is coated and modified with quaternary ammonium salt-modified TQ silicone resin. On the one hand, the TQ silicone resin has strong adhesion to the inorganic color powder and good compatibility with the silicone rubber base material, which can effectively improve the dispersion effect of the inorganic color powder in the silicone rubber base material, reduce the aggregation of the color powder, and improve the coloring effect; on the other hand, the quaternary ammonium salt coating modification of the inorganic color powder can significantly reduce the attractive aggregation between the color powder particles due to its cationic characteristics, improving the dispersion effect; on the third hand, the introduction of the quaternary ammonium salt can endow the silicone rubber with obvious antibacterial and mildew-proof characteristics.

[0025] (2) The antibacterial and mildew-proof colorant of the present invention uses hydroxyl silicone oil as a plasticizer, which can directly participate in the chemical cross-linking reaction of the alcohol-free silicone rubber and has no adverse effect on the mechanical properties of the alcohol-free silicone rubber.

[0026] (3) In the present invention, by further adding the quaternary ammonium salt-modified TQ silicone resin-coated inorganic color powder and hydroxyl silicone oil into methylcyclosiloxane and heating and stirring for homogenization treatment, through the swelling effect of methylcyclosiloxane on TQ silicone resin and the dissolution effect on hydroxyl silicone oil, it can significantly promote the formation of a semi-interpenetrating network of hydroxyl silicone oil in the TQ silicone resin coating layer, so as to better form a reinforcing structure during the chemical cross-linking reaction of the alcohol-free silicone rubber, achieving a good reinforcing effect. Specific embodiments

[0027] The following further describes the present invention in detail with reference to the embodiments, but the embodiments of the present invention are not limited thereto.

[0028] Example 1

[0029] A preparation method of an antibacterial and mildew-proof colorant for silicone rubber includes the following preparation steps:

[0030] (1) Add 150 g of methanol to a four-necked flask, then add 100 g of carbon black powder, 20 g of tetraethyl orthosilicate, and 20 g of dimethyloctadecyl [3-(trimethoxysilyl)propyl] ammonium chloride, stir and mix evenly, heat up to 50 °C, then dropwise add 10 g of ammonia water with a mass concentration of 25%, stir and react for 5 h. After the reaction is completed, carry out rotary evaporation and drying under vacuum to obtain quaternary ammonium salt-modified TQ silicone resin-coated carbon black powder.

[0031] (2) Add 100 g of DMC to a three-necked flask, then add 100 g of quaternary ammonium salt-modified TQ silicone resin-coated carbon black powder and 100 g of hydroxy silicone oil with a hydroxy content of 5% (wt.%) and a viscosity of 60 mm 2 / s (at 25 °C), heat to 80 °C, stir for homogenization treatment for 2 h, then carry out rotary evaporation under vacuum to remove DMC, and cool to room temperature to obtain an antibacterial, mildew-proof and coloring agent for silicone rubber with a viscosity of 2650 mm 2 / s.

[0032] Example 2

[0033] A preparation method of an antibacterial, mildew-proof and coloring agent for silicone rubber, comprising the following preparation steps:

[0034] (1) Add 150 g of ethanol to a four-necked flask, then add 100 g of carbon black powder, 10 g of tetraethyl orthosilicate, and 30 g of dimethyloctadecyl [3-(trimethoxysilyl)propyl] ammonium chloride, stir and mix evenly, heat up to 70 °C, then dropwise add 10 g of ammonia water with a mass concentration of 28%, stir and react for 4 h. After the reaction is completed, carry out rotary evaporation and drying under vacuum to obtain quaternary ammonium salt-modified TQ silicone resin-coated carbon black powder.

[0035] (2) Add 50 g of DMC to a three-necked flask, then add 50 g of quaternary ammonium salt-modified TQ silicone resin-coated carbon black powder and 100 g of hydroxy silicone oil with a hydroxy content of 5% (wt.%) and a viscosity of 60 mm 2 / s (at 25 °C), heat to 60 °C, stir for homogenization treatment for 4 h, then carry out rotary evaporation under vacuum to remove DMC, and cool to room temperature to obtain an antibacterial, mildew-proof and coloring agent for silicone rubber with a viscosity of 1600 mm 2 / s.

[0036] Example 3

[0037] A preparation method of an antibacterial, mildew-proof and coloring agent for silicone rubber, comprising the following preparation steps:

[0038] (1) Add 150 g of isopropanol to a four-necked flask, then add 100 g of carbon black powder, 30 g of tetraethyl orthosilicate, and 10 g of dimethyloctadecyl [3-(trimethoxysilyl)propyl] ammonium chloride, stir and mix evenly, heat up to 80 °C, then dropwise add 15 g of ammonia water with a mass concentration of 25% and stir for reaction for 5 h. After the reaction is completed, carry out rotary evaporation and drying under vacuum to obtain quaternary ammonium salt-modified TQ silicone resin-coated carbon black powder.

[0039] (2) Add 100 g of DMC to a three-necked flask, then add 100 g of quaternary ammonium salt-modified TQ silicone resin-coated carbon black powder and 50 g of hydroxyl silicone oil with a hydroxyl content of 5% (wt.%) and a viscosity of 60 mm 2 / s (at 25 °C), heat to 100 °C and stir for homogenization treatment for 3 h, then carry out rotary evaporation to remove DMC under vacuum, and cool to room temperature to obtain an antibacterial, mildew-proof and coloring agent for silicone rubber with a viscosity of 4700 mm 2 / s.

[0040] Example 4

[0041] A preparation method of an antibacterial, mildew-proof and coloring agent for silicone rubber, comprising the following preparation steps:

[0042] (1) Add 150 g of methanol to a four-necked flask, then add 100 g of titanium dioxide, 20 g of tetramethyl orthosilicate, and 20 g of dimethyloctadecyl [3-(trimethoxysilyl)propyl] ammonium chloride, stir and mix evenly, heat up to 40 °C, then dropwise add 15 g of ammonia water with a mass concentration of 25% and stir for reaction for 6 h. After the reaction is completed, carry out rotary evaporation and drying under vacuum to obtain quaternary ammonium salt-modified TQ silicone resin-coated titanium dioxide.

[0043] (2) Add 100 g of D5 to a three-necked flask, then add 100 g of quaternary ammonium salt-modified TQ silicone resin-coated titanium dioxide and 100 g of hydroxyl silicone oil with a hydroxyl content of 2% (wt.%) and a viscosity of 100 mm 2 / s (at 25 °C), heat to 90 °C and stir for homogenization treatment for 3 h, then carry out rotary evaporation to remove D5 under vacuum, and cool to room temperature to obtain an antibacterial, mildew-proof and coloring agent for silicone rubber with a viscosity of 2860 mm 2 / s.

[0044] Example 5

[0045] A preparation method of an antibacterial, mildew-proof and coloring agent for silicone rubber, comprising the following preparation steps:

[0046] (1) Add 150 g of methanol to a four-necked flask, then add 100 g of iron oxide pigment, 20 g of propyl orthosilicate, and 20 g of dimethyloctadecyl [3-(trimethoxysilyl)propyl] ammonium chloride, stir and mix evenly, heat up to 50 °C, then add dropwise 15 g of ammonia water with a mass concentration of 25%, stir and react for 4 h. After the reaction is completed, carry out rotary evaporation and drying under vacuum to obtain quaternary ammonium salt-modified TQ silicone resin-coated iron oxide pigment.

[0047] (2) Add 100 g of D4 to a three-necked flask, then add 100 g of quaternary ammonium salt-modified TQ silicone resin-coated iron oxide pigment and 100 g of hydroxy silicone oil with a hydroxyl content of 6% (wt.%) and a viscosity of 40 mm 2 / s (at 25 °C), heat to 80 °C, stir for homogenization for 1 h, then carry out rotary evaporation to remove D4 under vacuum, and cool to room temperature to obtain an antibacterial, mildew-proof and coloring agent for silicone sealant with a viscosity of 2520 mm 2 / s.

[0048] Example 6

[0049] A preparation method of an antibacterial and mildew-proof coloring agent for silicone sealant, compared with Example 1, DMC is not added in step (2) for homogenization treatment, and the preparation steps are as follows:

[0050] Step (1) is the same as that in Example 1.

[0051] (2) Heat 100 g of quaternary ammonium salt-modified TQ silicone resin-coated carbon black powder and 100 g of hydroxy silicone oil with a hydroxyl content of 5% (wt.%) and a viscosity of 60 mm 2 / s (at 25 °C) to 80 °C, stir and mix for 2 h to obtain an antibacterial and mildew-proof coloring agent for silicone sealant with a viscosity of 840 mm 2 / s.

[0052] Example 7

[0053] A preparation method of an antibacterial and mildew-proof coloring agent for silicone sealant, compared with Example 2, DMC is not added in step (2) for homogenization treatment, and the preparation steps are as follows:

[0054] Step (1) is the same as that in Example 1.

[0055] (2) Heat 50 g of quaternary ammonium salt-modified TQ silicone resin-coated carbon black powder and 100 g of hydroxy silicone oil with a hydroxyl content of 5% (wt.%) and a viscosity of 60 mm 2 / s (at 25 °C) to 60 °C, stir and mix for 4 h to obtain an antibacterial and mildew-proof coloring agent for silicone sealant with a viscosity of 510 mm 2 / s.

[0056] Example 8

[0057] A preparation method of an antibacterial and mildew-proof colorant for silicone sealant. Compared with Example 3, in step (2), DMC is not added for homogenization treatment, and the preparation steps are as follows:

[0058] Step (1) is the same as that in Example 1.

[0059] (2) Heat 100 g of quaternary ammonium salt-modified TQ silicone resin-coated carbon black powder and 50 g of hydroxyl silicone oil with a hydroxyl content of 5% (wt.%) and a viscosity of 60 mm 2 / s (at 25 °C) to 100 °C and carry out stirring and mixing treatment for 3 h to obtain an antibacterial and mildew-proof colorant for silicone sealant with a viscosity of 2150 mm 2 / s.

[0060] Comparative Example 1

[0061] A preparation method of an antibacterial and mildew-proof colorant for silicone sealant. Compared with Example 6, unmodified carbon black powder is used, and the preparation steps are as follows:

[0062] Heat 100 g of carbon black powder and 100 g of hydroxyl silicone oil with a hydroxyl content of 5% (wt.%) and a viscosity of 60 mm 2 / s (at 25 °C) to 80 °C and carry out stirring and mixing treatment for 2 h to obtain an antibacterial and mildew-proof colorant for silicone sealant with a viscosity of 750 mm 2 / s.

[0063] For the colorants obtained in the above Examples 1 to 3 and Examples 6 to 8, the coloring strength (refer to GB / T 3780.6-2016, which is the ratio of the light reflectance of industrial coloring reference carbon black (ITRB) to the test sample, with the effective mass of carbon black powder being 0.1 g) and the application performance in a de-alcohol type silicone sealant (100 parts of hydroxyl silicone oil, 50 parts of calcium carbonate, 20 parts of fumed silica, 10 parts of silane coupling agent KH-560, 10 parts of colorant, 1 part of titanate catalyst) were measured. The antibacterial and mildew-proof performance (refer to QB / T 2591-2003, testing the antibacterial grade and mildew grade); the mechanical properties were tested for tensile strength and elongation at break with reference to GB / T 528-2009). The results are shown in Table 1 below.

[0064] Table 1

[0065] Test sample Coloring intensity Antibacterial grade Mildew grade Tensile strength Elongation at break Example 1 96.6％ ≥99％ Level 0 5.2 MPa 460％ Example 2 97.1％ ≥99％ Level 0 4.5 MPa 410％ Example 3 96.0％ ≥99％ Level 0 5.6 MPa 495％ Example 6 96.7％ ≥99％ Level 0 4.6 MPa 415％ Example 7 96.8％ ≥99％ Level 0 4.0 MPa 382％ Example 8 96.0％ ≥99％ Level 0 4.7 MPa 420％ Comparative example 1 88.5％ No antibacterial effect No anti-mildew effect 3.8 MPa 346％

[0066] As can be seen from the results in Table 1, through the quaternary ammonium salt TQ silicone resin coating modification of the inorganic color powder, the present invention can significantly improve the dispersion effect of the inorganic color powder in hydroxyl silicone oil and the finally obtained silicone rubber, reduce the attractive agglomeration between color powder particles, thereby improving the coloring strength of the colorant and the mechanical strength of the silicone rubber. And it can endow the obtained silicone rubber with good antibacterial and mildew-proof effects. From the comparison results of Examples 1 to 3 and Examples 6 to 8, it can be seen that by further adding the quaternary ammonium salt-modified TQ silicone resin-coated inorganic color powder and hydroxyl silicone oil into methylcyclosiloxane and heating and stirring for homogenization treatment, the mechanical properties of the obtained silicone rubber can be improved by more than 10%. The reason is that the swelling effect of methylcyclosiloxane on TQ silicone resin and the dissolution effect on hydroxyl silicone oil during the homogenization treatment can significantly promote the formation of a semi-interpenetrating network of hydroxyl silicone oil in the TQ silicone resin coating layer, so as to better form a reinforcing structure during the chemical cross-linking reaction of the alcohol-free silicone rubber and achieve a good reinforcing effect.

[0067] The above embodiments are the preferred embodiments of the present invention, but the embodiments of the present invention are not limited by the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications made without departing from the spirit and principle of the present invention shall be equivalent replacement methods and are all included in the protection scope of the present invention.

Claims

1. A method for preparing an antibacterial and antifungal colorant for silicone adhesive, characterized in that: The method comprises the following preparation steps: (1) Inorganic color powder, silicate and dimethyloctadecyl[3-(trimethoxysilyl)propyl]ammonium chloride are added to a solvent and stirred to mix evenly, and then the temperature is raised to 40-80°C, and then ammonia water is added dropwise to stir and react. After the reaction is completed, vacuum drying is performed to obtain quaternary ammonium salt-modified TQ silicone resin-coated inorganic color powder; (2) the obtained quaternary ammonium salt modified TQ silicone resin coated inorganic color powder is mixed and dispersed evenly with hydroxy silicone oil to obtain an antibacterial and antifungal colorant for silicone adhesive; The method for uniformly dispersing the quaternary ammonium salt-modified TQ silicone resin-coated inorganic color powder and the hydroxy silicone oil is as follows: adding the quaternary ammonium salt-modified TQ silicone resin-coated inorganic color powder and the hydroxy silicone oil to methyl cyclosiloxane, heating and stirring for homogenization, and then vacuum removing the methyl cyclosiloxane to obtain an antibacterial and antifungal colorant for silicone adhesive; The methylcyclosiloxane is hexamethylcyclotrisiloxane, octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane or a mixed ring of dimethylsiloxane; the added amount of the methylcyclosiloxane is 50% to 200% of the mass of the hydroxy silicone oil; the temperature of the heating and stirring for homogenization treatment is 60 to 100° C., and the time is 1 to 4 hours.

2. The method for preparing an antibacterial and antifungal colorant for silicone adhesive according to claim 1, characterized in that: The inorganic color powder includes carbon powder, titanium dioxide, zinc oxide powder or iron oxide series color powder; the silicate is methyl orthosilicate, ethyl orthosilicate, propyl orthosilicate or butyl orthosilicate.

3. The method for preparing an antibacterial and antifungal colorant for silicone adhesive according to claim 1, characterized in that: The inorganic color powder, silicate and dimethyloctadecyl[3-(trimethoxysilyl)propyl]ammonium chloride are added in a mass ratio of 100:10~30:10~30.

4. The method for preparing an antibacterial and antifungal colorant for silicone adhesive according to claim 1, characterized in that: The solvent is methanol, ethanol or propanol.

5. The method for preparing an antibacterial and antifungal colorant for silicone adhesive according to claim 1, characterized in that: The mass concentration of the ammonia water is 25% to 28%, and the amount of ammonia water added is 10% to 50% of the total mass of the silicate and dimethyloctadecyl[3-(trimethoxysilyl)propyl]ammonium chloride.

6. The method for preparing an antibacterial and antifungal colorant for silicone adhesive according to claim 1, characterized in that: The hydroxyl content of the hydroxy silicone oil is 0.5% to 10%, and the viscosity is 15 to 200 mm 2 / s; the mass ratio of the quaternary ammonium salt modified TQ silicone resin coated inorganic color powder and the hydroxy silicone oil is 100:50~200.

7. An antibacterial and antifungal colorant for silicone adhesive, characterized in that: It is prepared by the method according to any one of claims 1 to 6.

8. Use of the antibacterial and antifungal colorant according to claim 7 in dealcoholized silicone adhesive.