Polyurethane sealant for power battery and preparation method thereof

Abstract

The invention relates to a polyurethane sealant for a power battery. The polyurethane sealant is prepared from the following components in parts by weight: 30 to 50 parts of self-made silicon modified diol, 10 to 20 parts of polyether diol, 10 to 20 parts of polyester diol, 12 to 25 parts of polyisocyanate and 4 to 8 parts of gaseous silicon. The polyurethane sealant prepared by the method provided by the invention has good high and low temperature resistance, has low storage modulus in a range of-30 DEG C to 60 DEG C, greatly reduces the occurrence of glue failure and other phenomena caused by temperature change, can form effective adhesion to different materials, and meets the requirement of no obvious strength attenuation for 1000 hours in a double-85 test; and the vehicle use requirements under most working conditions can be met.

Description

Technical Field

[0001] The invention belongs to the technical field of polyurethane adhesives, and in particular relates to a polyurethane sealant for power batteries and a preparation method thereof. Background Art

[0002] With the development of technology, new energy vehicles have entered thousands of households, but the endurance of new energy vehicles and their performance under harsh working conditions are not satisfactory. In order to solve these problems, on the one hand, power battery manufacturers have cancelled the original bolt fixation of the PACK seal for some models and replaced it with glue in order to increase the energy density of the battery. This puts higher requirements on the performance of the glue under various working conditions.

[0003] Although traditional polyurethane sealants can form good bonding effects, their modulus is relatively high at low temperatures, and there is a phenomenon of colloid debonding as the car vibrates and bumps; and although traditional silicone sealants perform well at low temperatures, their own bonding strength is not high and cannot meet the needs; this urgently requires the development of a sealant with excellent low-temperature flexibility and high bonding strength to meet the needs of technological development, and its market potential is huge. Summary of the invention

[0004] In view of the above deficiencies in the prior art, the present invention provides a polyurethane sealant for a power battery and a preparation method thereof.

[0005] The specific technical solutions are as follows:

[0006] One of the purposes of the present invention is to provide a polyurethane sealant for a power battery, which comprises the following components in parts by weight:

[0007] 30-50 parts of homemade silicon-modified diol, 10-20 parts of polyether diol, 10-20 parts of polyester diol, 12-25 parts of polyisocyanate, and 4-8 parts of gas silicon.

[0008] Furthermore, the polyether diol is a polypropylene oxide polyether with a molecular weight of 1000-3000.

[0009] Furthermore, the polyester diol is at least one of polycaprolactone diol, polycarbonate diol, adipic acid polyester diol, and phthalic anhydride polyester diol.

[0010] Furthermore, the polyisocyanate is diphenylmethane diisocyanate modified by carbonized diimide.

[0011] The second object of the present invention is to provide a method for preparing the polyurethane sealant for power batteries of the above-mentioned components, which comprises the following steps:

[0012] By weight, 30-50 parts of homemade silicon-modified diol, 10-20 parts of polyether diol, 10-20 parts of polyester diol, and 4-8 parts of gas silicon are dehydrated at 120°C and -0.095MPa for 2 hours. After dehydration, 12-25 parts of polyisocyanate are added thereto, and the mixture is reacted at 100-120°C for 1-3 hours to obtain a polyurethane sealant for power batteries.

[0013] Furthermore, the structural formula of the self-made silicon-modified diol is as follows:

[0014]

[0015] Furthermore, the synthesis method of the self-made silicon-modified diol comprises the following steps: taking 1 mol of maleic anhydride polybutadiene and 1.1 mol of heptamethyltrisiloxane with toluene as solvent, reacting at 75° C. for 24 hours under the catalysis of chloroplatinic acid and nitrogen protection, and then removing the solvent under reduced pressure rotary evaporation to obtain silylated maleic anhydride butadiene;

[0016] The molecular weight of the maleic anhydride polybutadiene is 1000-5400;

[0017] Silylated maleic anhydride butadiene and 1 mol of (1,4-butanediol) BDO were heated to 80°C in a nitrogen atmosphere on a device equipped with a reflux condenser to react until the acid value in the system was half of the initial acid value to obtain silylated maleic anhydride butadiene 1,4-butanediol monoester; then 1 mol of KH-560 was added and reacted at 110°C under the catalysis of tetramethylammonium chloride until the acid value was less than 5 mgKOH / g to obtain the target product. The reaction equation is as follows:

[0018]

[0019] The characteristics and beneficial effects of the present invention are:

[0020] (1) The present invention is a polyurethane sealant for power batteries. Compared with traditional polyurethane sealants, the addition of silicon groups greatly reduces the surface energy of the system, and can achieve effective bonding with a variety of materials. At the same time, the introduction of traditional silicon groups greatly improves the low-temperature flexibility of the sealant, and can maintain a low modulus at a low temperature.

[0021] (2) The maleic anhydride butadiene used in the present invention introduces a rubber structure into the molecular chain, which not only gives the system excellent elongation at break but also synergistically improves the low-temperature resistance of the system with silicon. At the same time, since butadiene can be greatly improved in compatibility with other resins in the system after being maleated, the stability of the system is greatly increased.

[0022] (3) The present invention uses self-made silicon-modified diols in combination with polyester and polyether diols, which can not only give the system excellent bonding properties to the original polyurethane sealant, but also give the system rubber, silicone and other characteristics to a large extent due to the introduction of rubber and silicon, which can better meet the demand for power battery sealants. DETAILED DESCRIPTION

[0023] The present invention is described below in conjunction with examples, which are only used to explain the present invention and are not used to limit the scope of the present invention.

[0024] In the specific implementation manner, the "parts" mentioned are all parts by weight.

[0025] Example 1

[0026] The method for synthesizing the self-made silicon-modified diol comprises the following steps: taking 1 mol of maleic anhydride polybutadiene with a molecular weight of 1000 and 1.1 mol of heptamethyltrisiloxane with toluene as solvent, reacting at 75° C. for 24 hours under the catalysis of chloroplatinic acid and nitrogen protection, and then removing the solvent under reduced pressure rotary evaporation to obtain silylated maleic anhydride butadiene;

[0027] Silylated maleic anhydride butadiene and 1 mol of BDO were heated to 80°C in a nitrogen atmosphere on a device equipped with a reflux condenser to react until the acid value in the system was half of the initial acid value to obtain silylated maleic anhydride butadiene 1,4-butanediol monoester; then 1 mol of KH-560 was added and reacted at 110°C under the catalysis of tetramethylammonium chloride until the acid value was less than 5 mgKOH / g to obtain the target product. The reaction equation is as follows:

[0028]

[0029] 50 parts of homemade silicon-modified diol, 10 parts of polypropylene oxide polyether with a molecular weight of 1000, 10 parts of polycarbonate diol with a molecular weight of 2000, and 8 parts of gas silicon were dehydrated at 120°C and -0.095MPa for 2 hours. After dehydration, 22 parts of diphenylmethane diisocyanate modified with carbonized diimide was added thereto, and the mixture was reacted at 120°C for 3 hours to obtain a polyurethane sealant for power batteries.

[0030] Example 2

[0031] The method for synthesizing the self-made silicon-modified diol comprises the following steps: taking 1 mol of maleic anhydride polybutadiene with a molecular weight of 2700 and 1.1 mol of heptamethyltrisiloxane with toluene as solvent, reacting at 75° C. for 24 hours under the catalysis of chloroplatinic acid and nitrogen protection, and then removing the solvent under reduced pressure rotary evaporation to obtain silylated maleic anhydride butadiene;

[0032] Silylated maleic anhydride butadiene and 1 mol of BDO were heated to 80°C in a nitrogen atmosphere on a device equipped with a reflux condenser to react until the acid value in the system was half of the initial acid value to obtain silylated maleic anhydride butadiene 1,4-butanediol monoester; then 1 mol of KH-560 was added and reacted at 110°C under the catalysis of tetramethylammonium chloride until the acid value was less than 5 mgKOH / g to obtain the target product. The reaction equation is as follows:

[0034]

[0035] 30 parts of homemade silicon-modified diol, 20 parts of polypropylene oxide polyether with a molecular weight of 2000, 20 parts of polycarbonate diol with a molecular weight of 1000, and 4 parts of gas silicon were dehydrated at 120°C and -0.095MPa for 2 hours. After dehydration, 18 diphenylmethane diisocyanate modified with carbonized diimide was added thereto and reacted at 120°C for 3 hours to obtain a polyurethane sealant for power batteries.

[0036] Comparative Example 1

[0037] Compared with Example 1, ordinary polypropylene oxide polyether diol replaces the self-made silicon-modified diol

[0038] Comparative Example 2

[0039] Conventional silicone sealant

[0040] test

[0041] The polyurethane sealants prepared in the above Examples 1-2 and the polyurethane sealants prepared in the comparative implementation were subjected to shear strength, DMA modulus and double 85 aging tests according to the adhesive test standard, and the elongation at break was tested according to GB / T30776-2014. The data results are shown in Tables 1 and 2, wherein the bonding materials for the shear strength test were 3003 aluminum-3003 aluminum and 3003 aluminum-electrophoretic aluminum, and cured at room temperature for 7 days.

[0042] Table 1. Comparison of shear strength and elongation at break of polyurethane sealants obtained in Examples 1-2 and Comparative Examples

[0043]

[0044] Table 2. Aging resistance test and modulus comparison of polyurethane sealants obtained in Example 1-2 and Comparative Example 1-2

[0045]

[0046] From the comparison of the data in Table 1 and Table 2, it can be seen that the performance test analysis of the polyurethane sealant obtained in Example 1-2 and Comparative Example 1-2 shows that the polyurethane seal prepared by the present invention can achieve bonding with 3003 aluminum and electrophoretic aluminum materials, and at the same time, the sealant has a lower low-temperature modulus, thereby giving the material excellent low-temperature resistance, and the introduction of silane and butadiene structures not only improves the double 85 aging performance of the product, but also makes the glue have better high-temperature resistance, thereby obtaining a relatively high high-temperature modulus and excellent elongation at break. Therefore, the polyurethane sealant prepared by the method of the present invention can meet the requirements of bonding and high and low temperature stability under the premise of high energy density requirements, which is of great significance to the next step of power battery development.

[0047] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A polyurethane sealant for power batteries, comprising the following components by weight: 30-50 parts of homemade silicon-modified diol, 10-20 parts of polyether diol, 10-20 parts of polyester diol, 12-25 parts of polyisocyanate, and 4-8 parts of gas silicon.

2. The polyurethane sealant for power batteries according to claim 1, characterized in that: The structural formula of the self-made silicon-modified diol is as follows: .

3. The polyurethane sealant for power battery according to claim 1, characterized in that: The synthesis method of the self-made silicon-modified diol comprises the following steps: taking 1 mol of maleic anhydride polybutadiene and 1.1 mol of heptamethyl trisiloxane with toluene as solvent, reacting at 75°C for 24 hours under the catalysis of chloroplatinic acid and the protection of nitrogen, and then removing the solvent under the condition of reduced pressure rotary evaporation to obtain silylated maleic anhydride butadiene; then heating the silylated maleic anhydride butadiene and 1 mol of 1,4-butanediol to 80°C on a device equipped with a reflux condenser and under a nitrogen atmosphere to react until the acid value in the system is half of the initial acid value to obtain silylated maleic anhydride butadiene 1,4-butanediol monoester; finally, adding 1 mol of KH-560 and reacting at 110°C under the catalysis of tetramethylammonium chloride until the acid value is less than 5 mgKOH / g to obtain the target product, and the reaction equation is as follows: 。 4. The polyurethane sealant for power batteries according to claim 1, characterized in that: The molecular weight of the maleic anhydride polybutadiene is 1000-5400.

5. The polyurethane sealant for power battery according to claim 1, characterized in that: The polyether diol is a polypropylene oxide polyether with a molecular weight of 1000-3000; the polyester diol is at least one of polycaprolactone diol, polycarbonate diol, adipic acid polyester diol, and phthalic anhydride polyester diol.

6. The polyurethane sealant for power battery according to claim 1, characterized in that: The polyisocyanate is diphenylmethane diisocyanate modified by carbonized diimide.

7. The method for preparing a polyurethane sealant for a power battery according to any one of claims 1 to 6, characterized in that: The method comprises the following steps: preparing 30-50 parts of self-made silicon-modified diol, 10-20 parts of polyether diol, 10-20 parts of polyester diol and 4-8 parts of gas silicon by weight, dehydrating the mixture at 120°C and -0.095MPa for 2 hours, adding 12-25 parts of polyisocyanate after dehydration, reacting the mixture at 100-120°C for 1-3 hours, and obtaining a polyurethane sealant for power batteries.

Images