Two-component polyurethane power encapsulant and preparation method thereof

Abstract

The application provides a two-component polyurethane power pouring sealant and a preparation method thereof. The polyurethane pouring sealant comprises A component and B component, the A component comprises modified castor oil, polyether polyol, plasticizer A, filler, water removing agent A, defoaming agent and catalyst, and the B component comprises isocyanate polymer, plasticizer B and water removing agent B. The A component and the B component are mixed according to a mass ratio of 5:1 to prepare the polyurethane power pouring sealant, the pouring sealant can still not foam and has little performance influence under the construction environment of high temperature, humidity and even water, the viscosity of the components is low, heating and vacuum defoaming are not needed even at low temperature, the adhesion effect on the cable is good, the cost is low, and the polyurethane power pouring sealant is beneficial to popularization and use.

Description

Technical Field

[0001] This invention relates to the field of polyurethane products technology, specifically to a two-component polyurethane electrical potting compound and its preparation method. Background Technology

[0002] With industrial development, the specifications and environments of power cables have changed significantly, and the sealing requirements for joints have become increasingly stringent. Many power cables now undergo a wrapping and potting process, utilizing electrical potting compound. This compound enhances the waterproofing, shock resistance, and heat dissipation of the power cables. Using electrical cable potting compound protects cables for extended periods in harsh environments such as high voltage and high current, effectively extending their lifespan. Power cables also possess strong resistance to high and low temperatures, excellent thermal insulation, and improved moisture resistance after potting.

[0003] This polyurethane potting compound technology is disclosed in inventions such as CN104592486A, CN104592928A, CN107286895A, and CN112724363B. In the aforementioned two-component polyurethane components, molecular sieves, calcium oxide, PTSI, or oxazolidine are typically used as dehydrating agents to absorb moisture introduced from the raw materials or during use, preventing the reaction with the isocyanate curing agent to generate carbon dioxide, forming bubbles that affect performance.

[0004] Compared to CN114192376A, it has lower construction requirements, requires no heating, and does not require vacuum degassing; compared to CN109777339A and CN111704884A, it has lower costs and is less affected by humidity or even water; compared to CN103881047A, component B uses modified isocyanate with extremely low NCO% content, reducing foaming when exposed to water. Summary of the Invention

[0005] This invention provides a two-component polyurethane electrical potting compound, its preparation method, and its application. It has low viscosity and high filling capacity. When using anhydrous calcium chloride with high water absorption as a dehydrating agent and combined with a low isocyanate content (calculated value less than 1%), it can achieve normal curing with up to 2% water addition without generating bubbles.

[0006] The objective of this invention is achieved through the following technical solution:

[0007] A first aspect of the present invention provides a two-component polyurethane electrical potting compound, comprising a component A and a component B, wherein component A comprises the following raw materials in parts by weight:

[0008]

[0009]

[0010] Component B comprises the following raw materials in parts by weight:

[0011] Isocyanate polymer: 80-90 parts;

[0012] Plasticizer B: 10-20 parts;

[0013] Dehydrating agent B: 3-5 parts.

[0014] The modified castor oil is hydroxyl-modified castor oil with a hydroxyl value of 10-100 mgKOH / g, preferably 10-65 mgKOH / g, and a viscosity range of 100-1000 mPa·s, preferably 100-300 mPa·s; for example, one or two of Itō URIC H-144, URIC H-1830, and URIC H-57, with URIC H-144 being preferred.

[0015] The polyether polyol is a terminal tertiary alcohol or a secondary alcohol (non-EO-terminated), with a molecular weight of 400-3000 and a functionality range of 2.5-3.5, such as one of Changhua CHE-7C21, CHE-2028, and glycerol, with CHE-7C21 being preferred.

[0016] The filler includes one or more of talc, calcium carbonate, mica powder, aluminum hydroxide, and wollastonite.

[0017] The catalyst includes at least one of dioctyltin dilaurate, dibutyltin dilaurate, diacetylacetonate dibutyltin, and dimethyltin oxide.

[0018] The defoamer includes one of BYK1790, BYK066N, and BYKW535.

[0019] The dehydrating agent is at least one of molecular sieve, calcium chloride, PTSI, and oxazolidine.

[0020] Anhydrous calcium chloride is preferred over calcium chloride.

[0021] The dehydrating agent is preferably a molecular sieve and anhydrous calcium chloride.

[0022] The weight ratio of the molecular sieve to anhydrous calcium chloride is 1:4-1:8; PTSI and oxazolidine are relatively expensive and not suitable for large-scale promotion and use.

[0023] Both plasticizer A and plasticizer B include environmentally friendly plasticizers, including at least one of dinonyl phthalate, diisodecyl phthalate, dioctyl terephthalate, 2,2,4-trimethyl-1,3-pentanediol diisobutyrate, diisononyl cyclohexane 1,2-dicarboxylate, alkyl sulfonate, 1,4-butyrolactone, or propylene carbonate.

[0024] The isocyanate polymer is a diphenylmethane-4,4'-diisocyanate modified product, wherein the isocyanate mass percentage is controlled at 3%-6%. This ensures that the theoretical NCO content before the reaction of components A and B is below 1%, for example, one of Huntsman suprasec 7811, suprasec 3222, suprasec 9506, and suprasec 9538, with suprasec 3222 being preferred.

[0025] A second aspect of the present invention provides a method for preparing a two-component polyurethane electrostatic potting compound, comprising the following steps:

[0026] (1) Preparation of component A:

[0027] S1: Mix modified castor oil, polyether polyol, and plasticizer A evenly, and vacuum dehydrate at 120-130℃ for 2-3 hours until the water content is ≤0.03%;

[0028] S2: After the temperature drops to room temperature, add dehydrating agent A, catalyst, and defoamer and mix well;

[0029] S3: Add filler to the raw materials that are mixed evenly in step S2, degas and mix evenly to obtain component A;

[0030] (2) Preparation of component B:

[0031] The isocyanate polymer, plasticizer B, and dehydrating agent B are mixed evenly and then degassed under vacuum to obtain component B.

[0032] When using, mix component A and component B at a mass ratio of 4:1 to 6:1 to prepare the two-component polyurethane electrical potting compound.

[0033] Compared with the prior art, the present invention has the following beneficial effects:

[0034] (1) The two-component polyurethane electrical potting compound provided by this invention uses anhydrous calcium chloride and molecular sieve as dehydrating agents. Anhydrous calcium chloride has a large water absorption capacity, low cost, does not increase viscosity, is easy to apply, does not require heating to aid flow or vacuum degassing, has low cost, and has good bonding effect on cables. Compared with CN114192376A, the application requirements are lower, no heating or vacuum degassing is required; compared with CN109777339A and CN111704884A, the cost is lower, and the impact on humidity and even water is smaller; compared with CN103881047A, component B uses modified isocyanate with extremely low NCO% content, reducing foaming when exposed to water.

[0035] (2) The two-component polyurethane electrical potting compound provided by the present invention uses modified isocyanate in component B, with extremely low NCO% content, which reduces foaming when exposed to water. The calculated NCO value before mixing reaction is less than 1%, which can achieve mixing with up to 2% water and normal curing without producing bubbles, thus avoiding product sealing and electrical performance defects.

[0036] (3) Polyurethane electrical potting compound is prepared by mixing component A and component B in a mass ratio of 4:1-6:1. It can still be potted without foaming in high temperature, humidity or even water-containing construction environments, with little impact on performance. At the same time, the component viscosity is low, so even at low temperature, there is no need for heating to aid flow and vacuum degassing. It has good bonding effect on cables, low cost control, and is conducive to promotion and use. Detailed Implementation

[0037] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make several changes and improvements without departing from the concept of the present invention. These all fall within the protection scope of the present invention.

[0038] In the following embodiments and comparative examples:

[0039] Modified castor oil URIC H-144: Ito Oil Co., Ltd., Japan

[0040] Tertiary alcohol-terminated polyether polyol CHE-7C21: Changhua Chemical Technology Co., Ltd.

[0041] Primary alcohol-terminated polyether polyols VORANOL TM CP 450: Dow Chemical Company

[0042] DINCH: BASF GmbH, Germany

[0043] propylene carbonate (Jeffsol): Huntsman Corporation

[0044] Activated Heavy Calcium Carbonate Omyacarb 2T: Swiss Omyacarb

[0045] Molecular sieve ( NK 30AP): Arkema, France

[0046] Defoamer BYK-066N: BYK Chemicals

[0047] DBTDL: Nitto Kasei Corporation

[0048] Isocyanate polymer suprasec 3222; wherein NCO is 6% by mass: Huntsman Corporation

[0049] Isocyanate polymer suprasec 2060; wherein NCO mass percentage is 16%: Huntsman Corporation

[0050] TXIB: Eastman

[0051] Examples 1-3

[0052] Examples 1-3 provide a two-component polyurethane electrical potting compound and its preparation method. The specific steps are as follows: (Weigh each component according to the weight parts described in Table 1)

[0053] (1) Preparation of component A:

[0054] S1: Spread the filler on a tray and place it in a vacuum oven (pressure gauge vacuum reaches -0.08MPa to -0.1MPa), treat at 100℃ for 12h and maintain pressure to cool down to room temperature. Pack the powder into a sealed container and place it in a desiccator for storage until later use.

[0055] S2: Mix modified castor oil, polyether polyol, and plasticizer A evenly, and dehydrate under vacuum at 130℃ (pressure gauge vacuum degree reaches -0.08MPa to -0.1MPa) for 2 to 3 hours until the moisture content is ≤0.03%;

[0056] S3: After the temperature drops to room temperature, add dehydrating agent A, catalyst, and defoamer and mix.

[0057] S4: Add filler to the raw materials that are mixed evenly in step S3, degas and mix evenly to obtain component A;

[0058] (2) Preparation of component B:

[0059] The isocyanate polymer, plasticizer B, and dehydrating agent B are mixed evenly and then degassed under vacuum (pressure gauge vacuum reaches -0.08MPa to -0.1MPa) to obtain component B.

[0060] Table 1. Formulations in Examples 1-3

[0061]

[0062]

[0063] Comparative Example 1

[0064] The difference between this comparative example and Example 1 is that the amount of molecular sieve used is 3 parts and the amount of anhydrous calcium chloride used is 2 parts.

[0065] Comparative Example 2

[0066] The difference between this comparative example and Example 2 is that calcium oxide is used instead of anhydrous calcium chloride.

[0067] Comparative Example 3

[0068] The difference between this comparative example and Example 2 is that conventional refined castor oil was used instead of modified castor oil URIC H-144.

[0069] Comparative Example 4

[0070] The difference between this comparative example and Example 2 is that it uses VORANOL, a polyether polyol with conventional primary alcohol end-capping. TM CP450 as a substitute for tertiary alcohol-terminated polyether polyol CHE-7C21

[0071] Comparative Example 5

[0072] The difference between this comparative example and Example 3 is that the isocyanate polymer suprasec 2060 with 16% NCO content isocyanate polymer suprasec 3222 is used instead of the isocyanate polymer suprasec 3222 with 6% NCO content.

[0073] Performance testing

[0074] Two-component polyurethane electrical potting compounds were prepared using Examples 1-3 and Comparative Examples 1-5. The mixing properties, shear strength, dielectric strength, volume resistivity, Shore A hardness, NCO%, viscosity, and leveling properties of the materials after adding water were tested. The test conditions and test standards are shown in Table 2.

[0075] Table 2 Test Standards and Test Methods (Mix component A and component B at a weight ratio of 5:1)

[0076]

[0077] The test results of the two-component polyurethane electrostatic potting compounds in Examples 1-3 and Comparative Examples 1-5 are shown in Table 3 below.

[0078] Table 3 Test Data

[0079]

[0080]

[0081] Results analysis:

[0082] Example 1 showed the best leveling and filling effect, Example 2 was slightly slower in leveling, while Comparative Example 1 had a higher viscosity, which affected the leveling and filling effect. At the same time, the water absorption was insufficient, and the excess water reacted with the isocyanate of component B, resulting in bubbles.

[0083] Compared with Comparative Example 2, Example 2 used calcium oxide. Due to its alkalinity, it was found to thicken during storage, resulting in unsatisfactory leveling properties. It also reduced the vulcanization rate and caused slight bubbling.

[0084] Based on Examples 1, 2, 1, and 2, the economical and qualified dehydrating agent combination can only be a small amount of molecular sieve combined with anhydrous calcium chloride.

[0085] Compared with Example 2, Comparative Examples 3 and 4 used conventional castor oil and polyether polyol, which increased the OH% and thus increased the NCO%. After mixing, the NCO% exceeded 1%, resulting in more foaming in the water mixing test.

[0086] Comparative Example 5 used a higher NCO% grade of isocyanate component diluted with plasticizer, but the NCO% was still higher than that of Example 3, and more foaming occurred in the water mixing test.

[0087] The above description of the embodiments is provided to enable those skilled in the art to understand and use the invention. It will be apparent to those skilled in the art that various modifications can be made to these embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, the present invention is not limited to the above embodiments, and any improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the invention should be within the protection scope of the present invention.

Claims

1. A two-component polyurethane electrical potting compound, characterized in that: It includes component A and component B, wherein component A comprises the following raw materials in parts by weight: Modified castor oil: 10-20 parts; Polyether polyol: 5-10 parts; Plasticizer A: 10-15 parts; Filler: 55-65 parts; Dehydrating agent A: 5-10 parts; Defoamer: 0.1-1 part; Catalyst: 0.1-0.5 parts; Component B comprises the following raw materials in parts by weight: Isocyanate polymer: 80-90 parts; Plasticizer B: 10-20 parts; Dehydrating agent B: 3-5 parts; The modified castor oil is hydroxyl-modified castor oil with a hydroxyl value of 10-100 mgKOH / g. The polyether polyol is a terminal tertiary alcohol or a secondary alcohol, with a functionality range of 2.5-3.

5. The isocyanate polymer is modified diphenylmethane-4,4'-diisocyanate, wherein the mass percentage of isocyanate is controlled at 3%-6%; The dehydrating agent A is a molecular sieve and anhydrous calcium chloride, and the weight ratio of the molecular sieve to anhydrous calcium chloride is 1:4-1:

8.

2. The two-component polyurethane electrical potting compound according to claim 1, characterized in that: The modified castor oil has a viscosity range of 100-1000 mPa·s.

3. The two-component polyurethane electrical potting compound according to claim 1, characterized in that: The molecular weight range of the polyether polyol is 400-3000.

4. The two-component polyurethane electrical potting compound according to claim 1, characterized in that: The filler includes one or more of talc, calcium carbonate, mica powder, aluminum hydroxide, and wollastonite.

5. The two-component polyurethane electrical potting compound according to claim 1, characterized in that: The catalyst includes at least one of dioctyltin dilaurate, dibutyltin dilaurate, diacetylacetonate dibutyltin, and dimethyltin oxide.

6. The two-component polyurethane electrical potting compound according to claim 1, characterized in that: The defoamer includes one of BYK1790, BYK066N, and BYKW535.

7. The two-component polyurethane electrical potting compound according to claim 1, characterized in that: The dehydrating agent B includes at least one of molecular sieve, calcium chloride, PTSI, and oxazolidine.

8. The two-component polyurethane electrical potting compound according to claim 1, characterized in that: Both plasticizer A and plasticizer B include environmentally friendly plasticizers; the environmentally friendly plasticizers include at least one of dinonyl phthalate, diisodecyl phthalate, dioctyl terephthalate, 2,2,4-trimethyl-1,3-pentanediol diisobutyrate, diisononyl cyclohexane 1,2-dicarboxylate, alkyl sulfonate, 1,4-butyrolactone, or propylene carbonate.

9. A method for preparing a two-component polyurethane electrostatic potting compound as described in any one of claims 1-8, characterized in that, Includes the following steps: (1) Preparation of component A: S1: Mix modified castor oil, polyether polyol, and plasticizer A evenly; vacuum dehydrate at 120-130℃ for 2-3 hours until the water content is ≤0.03%; S2: After the temperature drops to room temperature, add dehydrating agent A, catalyst, and defoamer and mix well; S3: Add filler to the raw materials that are mixed evenly in step S2, degas and mix evenly to obtain component A; (2) Preparation of component B: The isocyanate polymer, plasticizer B, and dehydrating agent B are mixed evenly and then degassed under vacuum to obtain component B.

Images