A catalyst for refractory mica tape, an organosilicon adhesive, and their preparation method

Abstract

This invention discloses a catalyst for refractory mica tape, an organosilicon adhesive, and their preparation method. The adhesive is prepared from a specific ratio of organic solvent, hydroxyl-terminated silicone rubber, organosilicon resin, the refractory mica tape catalyst, and a stabilizer. The catalyst for refractory mica tape of this invention exhibits high catalytic activity and automatically decomposes without residue at around 130°C. Therefore, the production process of the organosilicon adhesive does not introduce organic amines that corrode the copper core or metal salts that affect electrical properties, thus maintaining the insulation of the mica tape and resulting in refractory mica tape with excellent insulation. The organosilicon adhesive of this invention, due to the use of a special catalyst, possesses excellent properties including high-temperature resistance, no corrosion to the copper core, absence of metal ions, and superior cohesive strength and peel strength.

Description

Technical Field

[0001] This invention relates to the field of mica tape adhesive technology, specifically to a catalyst for refractory mica tape, an organosilicon adhesive, and a method for preparing the same. Background Technology

[0002] Fire-resistant mica tape, or simply mica tape, is a type of fire-resistant insulating material. It can be categorized by application into fire-resistant mica tape for motors and fire-resistant mica tape for fire-resistant cables. Based on structure, it can be classified as double-sided tape, single-sided tape, three-in-one tape, double-film tape, and single-film tape. According to the type of mica used, it can be further classified as synthetic mica tape, phlogopite mica tape, and muscovite mica tape.

[0003] Fire-resistant cable mica tape is a high-performance mica insulation product with excellent high-temperature resistance and flame retardancy. It is made of high-quality phlogopite or synthetic mica paper as the base material, with electrical alkali-free fiberglass cloth or polyolefin film as the reinforcing material, and bonded with high-temperature silicone resin modified adhesive. After high-temperature baking, drying, and slitting, it is processed into tape or roll fire-resistant insulating material and wrapped around the surface of the cable. This ensures the high-temperature insulation performance of the cable in the event of a fire, giving workers valuable time for emergency response and escape.

[0004] Fire-resistant mica tape used in fire-resistant cables must have a dry, non-adhesive surface, good flexibility and suppleness, high tensile strength when wrapping wires and cables at high speed, and must not fray or break.

[0005] Currently, the catalysts used in the production process of silicone-modified adhesives for mica tape fall into two categories: one is organic amines, such as ethylenediamine, diethylenetriamine, and triethylenetetramine, which have a certain corrosive effect on the copper core; the other is acetate or tin salts containing metal ions, such as sodium acetate, potassium acetate, dibutyltin dilaurate, and stannous octoate. The former leads to corrosion of the copper core, while the latter introduces metal ions into the mica tape, reducing its insulation properties. Furthermore, the resulting silicone-modified adhesive has a low degree of cross-linking, resulting in low bonding strength after curing. Summary of the Invention

[0006] To address the problems existing in the prior art, this invention provides a catalyst for fire-resistant mica tape, an organosilicon adhesive, and a method for preparing the same. The organosilicon adhesive, due to the use of a special catalyst, exhibits excellent properties such as high temperature resistance, no corrosion to the copper core, absence of metal ions, and superior cohesiveness and peel strength.

[0007] The technical solution adopted to achieve the above-mentioned objectives of this invention is as follows:

[0008] A catalyst for refractory mica tape is prepared by the following method:

[0009] Under inert gas protection, octamethylcyclotetrasiloxane and tetramethylammonium hydroxide pentahydrate were stirred and reacted at 65–75 °C for 2.5–4.5 h. After the reaction was completed, the mixture was cooled to room temperature to obtain the catalyst for refractory mica tape.

[0010] Furthermore, the mass ratio of the octamethylcyclotetrasiloxane to the tetramethylammonium hydroxide pentahydrate is 20-30:0.75-2.

[0011] An organosilicon adhesive for fire-resistant mica tape is prepared from the following raw materials in parts by weight:

[0012]

[0013] Furthermore, the organic solvent is xylene or butyl acetate.

[0014] Furthermore, the hydroxyl-terminated silicone rubber is a silicone rubber with a viscosity-average molecular weight of 500,000 to 800,000 and hydroxyl-terminated ends.

[0015] Furthermore, the organosilicon resin is an MQ organosilicon resin formed by tetrafunctional siloxane units Q and monofunctional siloxane units M, with a molar mass of 1000-8000 g / mol and an M / Q ratio of 0.5-0.8.

[0016] Furthermore, the stabilizer is isopropanol.

[0017] A method for preparing an organosilicon adhesive for fire-resistant mica tape includes the following steps:

[0018] S1. Add organic solvent to the reactor, start stirring, then add hydroxyl-terminated silicone rubber and silicone resin, heat to 60-80℃, and at the same time purge inert gas into the reactor for protection. After holding at 60-80℃ for 0.5-1h, the materials in the reactor will be completely dissolved and homogeneous.

[0019] S2. Add refractory mica with catalyst to the reactor, continue to keep warm for 0.5-2 hours, then raise the temperature to 90-120℃ and reflux for 2.5-4 hours, then raise the temperature to 130-135℃ and reflux for 0.1-1 hours.

[0020] S3. Cool down to below 75°C, add stabilizer, stir evenly, and obtain the organosilicon adhesive for fire-resistant mica tape.

[0021] Compared with the prior art, the beneficial effects and advantages of the present invention are as follows:

[0022] 1. The catalyst for the refractory mica tape of the present invention has high catalytic activity. Conventional silicone adhesives for mica tapes mostly use organotin salts or polyamine catalysts, with an addition amount of about one-thousandth of the mica tape mass. However, the catalyst of the present invention only needs to be added to one ten-thousandth of the mica tape mass (calculated as tetramethylammonium hydroxide) to achieve the same effect. Moreover, the catalyst of the present invention will automatically decompose without residue at around 130°C. Therefore, the production process of silicone adhesives will not introduce organic amines that corrode the copper core or metal salts that affect electrical properties, and will not reduce the insulation of the mica tape. The prepared refractory mica tape has good insulation.

[0023] 2. The silicone adhesive of this invention is heat-resistant and has excellent cohesiveness and peel strength, resulting in high bonding strength. Commercially available mica tape adhesives have a peel strength of approximately 6 KN / m at 180°, while the adhesive prepared in this invention has a peel strength >10 KN / mm at 180°.

[0024] 3. The raw materials for preparing the catalyst and organosilicon adhesive for refractory mica tape of the present invention are inexpensive and readily available, resulting in a low cost of the prepared organosilicon adhesive. Moreover, the process for preparing the organosilicon adhesive is simple, easy to operate, and easy to industrialize. Detailed Implementation

[0025] The present invention will now be described with reference to specific embodiments, but these are not intended to limit the scope of the invention.

[0026] Example 1

[0027] A catalyst for refractory mica tape is prepared by the following method:

[0028] 30 kg of octamethylcyclotetrasiloxane and 0.75 kg of tetramethylammonium hydroxide pentahydrate were added to a stainless steel reactor. Dry nitrogen gas was uniformly blown into the reactor from the bottom while the temperature was raised to 65°C. The reaction was maintained at 65°C for 3.5 hours, and then cooled to room temperature under nitrogen protection to obtain the catalyst for refractory mica belts.

[0029] Example 2

[0030] An organosilicon adhesive for fire-resistant mica tape is prepared from the following raw materials in parts by weight:

[0031]

[0032] The viscosity-average molecular weight of hydroxyl-terminated silicone rubber is 500,000.

[0033] The silicone resin has an M / Q ratio of 0.6 and a molecular weight of 5000.

[0034] The preparation method of the above-mentioned organosilicon adhesive for refractory mica tape is as follows:

[0035] S1. Add xylene to the reactor, start stirring, then add hydroxyl-terminated silicone rubber and organosilicon resin, heat to 75°C, and simultaneously introduce dry nitrogen gas into the bottom of the reactor. After maintaining the temperature at 75°C for 0.5 hours, the materials in the reactor will be completely dissolved and homogeneous.

[0036] S2. Add refractory mica with catalyst to the reactor, continue to keep warm for 1 hour, then raise the temperature to 116°C and reflux for 3 hours, then raise the temperature to 135°C and reflux for 1 hour.

[0037] S3. Cool to 72°C, add isopropanol, stir for 20 minutes to obtain the organosilicon adhesive for fire-resistant mica tape.

[0038] Example 3

[0039] An organosilicon adhesive for fire-resistant mica tape is prepared from the following raw materials in parts by weight:

[0040]

[0041] The viscosity-average molecular weight of hydroxyl-terminated silicone rubber is 600,000.

[0042] The silicone resin has an M / Q ratio of 0.7 and a molecular weight of 4500.

[0043] The preparation method of the above-mentioned organosilicon adhesive for refractory mica tape is as follows:

[0044] S1. Add xylene to the reactor, start stirring, then add hydroxyl-terminated silicone rubber and organosilicon resin, heat to 75°C, and simultaneously introduce dry nitrogen gas into the bottom of the reactor. After maintaining the temperature at 75°C for 0.5 hours, the materials in the reactor will be completely dissolved and homogeneous.

[0045] S2. Add refractory mica with catalyst to the reactor, continue to keep warm for 1 hour, then raise the temperature to 115°C and reflux for 3 hours, then raise the temperature to 135°C and reflux for 0.5 hours.

[0046] S3. Cool to 65°C, add isopropanol, stir for 20 minutes to obtain the organosilicon adhesive for fire-resistant mica tape.

[0047] Example 4

[0048] An organosilicon adhesive for fire-resistant mica tape is prepared from the following raw materials in parts by weight:

[0049]

[0050] The viscosity-average molecular weight of hydroxyl-terminated silicone rubber is 750,000.

[0051] The silicone resin has an M / Q ratio of 0.8 and a molecular weight of 3600.

[0052] The preparation method of the above-mentioned organosilicon adhesive for refractory mica tape is as follows:

[0053] S1. Add xylene to the reactor and start stirring. Then add hydroxyl-terminated silicone rubber and organosilicon resin, heat to 75°C, and simultaneously introduce dry nitrogen gas into the bottom of the reactor. After holding at 75°C for 45 minutes, the materials in the reactor will be completely dissolved and homogeneous.

[0054] S2. Add refractory mica with catalyst to the reactor, continue to keep warm for 1 hour, then raise the temperature to 115°C and reflux for 3 hours, then raise the temperature to 135°C and reflux for 0.5 hours.

[0055] S3. Cool to 70°C, add isopropanol, stir for 15 minutes to obtain the organosilicon adhesive for fire-resistant mica tape.

[0056] Comparative Example 1

[0057] An organosilicon adhesive for fire-resistant mica tape is prepared from the following raw materials in parts by weight:

[0058]

[0059] The viscosity-average molecular weight of hydroxyl-terminated silicone rubber is 500,000.

[0060] The silicone resin has an M / Q ratio of 0.6 and a molecular weight of 5000.

[0061] The preparation method of the above-mentioned organosilicon adhesive for refractory mica tape is as follows:

[0062] S1. Add xylene to the reactor, start stirring, then add hydroxyl-terminated silicone rubber and organosilicon resin, heat to 75°C, and simultaneously introduce dry nitrogen gas into the bottom of the reactor. After maintaining the temperature at 75°C for 0.5 hours, the materials in the reactor will be completely dissolved and homogeneous.

[0063] S2. Add ethylenediamine into the reactor and continue to keep it warm for 1 hour. Then raise the temperature to 116°C and reflux for 3 hours. Next, raise the temperature to 135°C and reflux for 1 hour.

[0064] S3. Cool to 72°C, add isopropanol, stir for 20 minutes to obtain the organosilicon adhesive for fire-resistant mica tape.

[0065] Comparative Example 2

[0066] An organosilicon adhesive for fire-resistant mica tape is prepared from the following raw materials in parts by weight:

[0067]

[0068]

[0069] The viscosity-average molecular weight of hydroxyl-terminated silicone rubber is 500,000.

[0070] The silicone resin has an M / Q ratio of 0.6 and a molecular weight of 5000.

[0071] The preparation method of the above-mentioned organosilicon adhesive for refractory mica tape is as follows:

[0072] S1. Add xylene to the reactor, start stirring, then add hydroxyl-terminated silicone rubber and organosilicon resin, heat to 75°C, and simultaneously introduce dry nitrogen gas into the bottom of the reactor. After maintaining the temperature at 75°C for 0.5 hours, the materials in the reactor will be completely dissolved and homogeneous.

[0073] S2. Add dibutyltin dilaurate to the reactor and continue to keep warm for 1 hour. Then raise the temperature to 116°C and reflux for 3 hours. Next, raise the temperature to 135°C and reflux for 1 hour.

[0074] S3. Cool to 72°C, add isopropanol, stir for 20 minutes to obtain the organosilicon adhesive for fire-resistant mica tape.

[0075] Comparative Example 3

[0076] An organosilicon adhesive for fire-resistant mica tape is prepared from the following raw materials in parts by weight:

[0077]

[0078] The viscosity-average molecular weight of hydroxyl-terminated silicone rubber is 500,000.

[0079] The silicone resin has an M / Q ratio of 0.6 and a molecular weight of 5000.

[0080] The preparation method of the above-mentioned organosilicon adhesive for refractory mica tape is as follows:

[0081] S1. Add xylene to the reactor, start stirring, then add hydroxyl-terminated silicone rubber and organosilicon resin, heat to 75°C, and simultaneously introduce dry nitrogen gas into the bottom of the reactor. After maintaining the temperature at 75°C for 0.5 hours, the materials in the reactor will be completely dissolved and homogeneous.

[0082] S2. Add diethylenetriamine to the reactor and continue to keep it warm for 1 hour. Then raise the temperature to 116°C and reflux for 3 hours. Next, raise the temperature to 135°C and reflux for 1 hour.

[0083] S3. Cool to 72°C, add isopropanol, stir for 20 minutes to obtain the organosilicon adhesive for fire-resistant mica tape.

[0084] The high-temperature resistance, tensile strength, peel strength, and bonding properties of the silicone adhesives for refractory mica tapes prepared in Examples 2-4 and Comparative Examples 1-3 were tested. The results are shown in Table 1 below:

[0085] Table 1. Performance of silicone adhesives for fire-resistant mica tape

[0086]

[0087] As shown in Table 1, the silicone adhesives prepared in Examples 2-4 have advantages such as good high temperature resistance, high tensile strength, high peel strength and good adhesion.

Claims

1. An organosilicon adhesive for fire-resistant mica tape, characterized in that... It is prepared from the following raw materials in parts by weight: 15-30 parts of organic solvent 10 parts of hydroxyl-terminated silicone rubber 10-25 parts of silicone resin 0.025–0.06 parts of catalyst for refractory mica tape Stabilizer 0.05–1.2 parts; The catalyst for the refractory mica tape is prepared by the following method: Under inert gas protection, octamethylcyclotetrasiloxane and tetramethylammonium hydroxide pentahydrate were stirred and reacted at 65–75 °C for 2.5–4.5 h. After the reaction was completed, the mixture was cooled to room temperature to obtain the catalyst for refractory mica tape.

2. The silicone adhesive for refractory mica tape according to claim 1, characterized in that: The mass ratio of the octamethylcyclotetrasiloxane to tetramethylammonium hydroxide pentahydrate is 20-30: 0.75-2.

3. The silicone adhesive for refractory mica tape according to claim 1, characterized in that: The organic solvent is xylene or butyl acetate.

4. The silicone adhesive for refractory mica tape according to claim 1, characterized in that: The organosilicon resin is an MQ organosilicon resin formed by tetrafunctional siloxane units Q and monofunctional siloxane units M, with a molar mass of 1000-8000 g / mol and an M / Q ratio of 0.5-0.

8.

5. The silicone adhesive for refractory mica tape according to claim 1, characterized in that: The stabilizer is isopropanol.

6. A method for preparing the silicone adhesive for refractory mica tape according to claim 1, characterized in that... Includes the following steps: S1. Add organic solvent to the reactor, start stirring, then add hydroxyl-terminated silicone rubber and silicone resin, heat to 60-80℃, and at the same time purge inert gas into the reactor for protection. After holding at 60-80℃ for 0.5-1h, the materials in the reactor will be completely dissolved and homogeneous. S2. Add refractory mica with catalyst to the reactor, continue to keep warm for 0.5-2 hours, then raise the temperature to 90-120℃ and reflux for 2.5-4 hours, then raise the temperature to 130-135℃ and reflux for 0.1-1 hours. S3. Cool down to below 75°C, add stabilizer, stir evenly, and obtain the organosilicon adhesive for fire-resistant mica tape.

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