Preparation method of water-based polyester insulating paint for aluminum shell battery cell of new energy automobile

Abstract

The invention discloses a preparation method of a water-based polyester insulating coating for an aluminum shell battery cell of a new energy automobile, a pre-polymerization-polymerization two-step method is adopted to synthesize a water-based polyester matrix, and the addition weight ratio of sodium 5-sulfoisophthalic acid to neopentyl glycol is controlled, so that the reaction conditions can be better controlled, and the stability of the water-based polyester insulating coating is improved. The dispersity, the stability, the water resistance, the heat resistance and other mechanical properties of the coating are improved compared with those of a paint coating obtained through one-step synthesis.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of coatings, and particularly relates to a preparation method of a water-based polyester insulation coating for an aluminum shell battery cell of a new energy vehicle. BACKGROUND

[0002] With the increasing demand for environmental protection, the research and development of environmentally friendly coatings have been valued and have developed rapidly; among them, water-based coatings belong to environmentally friendly coatings, do not require special construction equipment, have a wide range of applications, and are the most important development. Water-based polyester coatings are a representative type of water-based coatings, which are widely used for the protection and decoration of metal and wooden surfaces, and have the characteristics of high gloss, strong adhesion, high fullness, excellent impact resistance, etc. Water-based polyester resin is a polyester with water as the dispersion medium. Water-based polyester generally contains hydroxyl and carboxyl groups, with an acid value of 35-60 mg KOH / g. Unreacted carboxyl groups are neutralized into salts with amines to impart water solubility.

[0003] In the traditional polymerization method of water-based polyester, the early synthesis of water-based polyurethane used forced emulsification, that is, a polyurethane polymer with a certain molecular weight was first prepared, and then it was dispersed in water with a certain amount of emulsifier under strong stirring. This method requires the addition of emulsifiers, and the amount of emulsifier is large. Moreover, the emulsion particle size is large, the distribution is wide, and the stability is poor, so this method has been rarely used. When hydrophilic monomers (such as sodium 5-sulfonate) are added to copolymerize with other hydrophobic monomers, phase separation easily occurs, resulting in uneven distribution of sulfonic acid groups in the molecular chain. This not only reduces the water dispersibility of the resin, but also causes the particle size distribution of the dispersion to be wide, which further leads to a decrease in the water resistance, heat resistance, and mechanical properties of the coating. SUMMARY

[0004] The technical problem to be solved by the present application is to provide a preparation method of a water-based polyester insulation coating for an aluminum shell battery cell of a new energy vehicle, which solves the problems of poor dispersibility, low stability, poor heat resistance, and decreased mechanical properties of existing water-based polyester insulation coatings.

[0005] The content of the present application includes: A preparation method of a water-based polyester insulation coating for an aluminum shell battery cell of a new energy vehicle, comprising the following steps: (1) Take the following weight percentages of components: neopentyl glycol 30-40%, phthalic anhydride 20-30%, adipic acid 20-30%, m-phenylenediamine-5-sulfonic acid sodium 10-20%, trimethylolpropane 6-16%, and p-toluenesulfonic acid 0.5-1.5%; (2) mixing isophthalic acid-5-sodium sulfonate and part of neopentyl glycol with a certain amount of water in a certain proportion, adding into a four-necked flask with mechanical stirring, thermometer, condenser tube and nitrogen device, starting stirring, heating and warming, keeping warm until the white insoluble matter disappears to obtain a prepolymer; (3) adding the rest of neopentyl glycol, adipic acid, phthalic anhydride, trimethylolpropane and p-toluene sulfonic acid into the prepolymer, warming to a certain temperature, and cooling to obtain a polyester water dispersion; (4) weighing a certain amount of the polyester water dispersion, adding deionized water, stirring at a certain temperature, and then standing to obtain a water-based polyester dispersion; (5) adding a curing agent, a catalyst, a pigment, a filler and a cosolvent into the polyester water dispersion, and mixing to obtain a water-based polyester insulating coating.

[0006] In one embodiment, the weight ratio of isophthalic acid-5-sodium sulfonate to neopentyl glycol in step (2) is 1:1-2.

[0007] In one embodiment, the amount of water added in step (2) is 2-3 times the sum of the amounts of isophthalic acid-5-sodium sulfonate and neopentyl glycol.

[0008] In one embodiment, the temperature in step (2) is warmed to 145-155℃.

[0009] In one embodiment, the warming method in step (3) is: warming at 145-155℃ for 1 hour, warming at 165-175℃ for 1 hour, and warming at 185-195℃ for 1 hour. In one embodiment, the temperature in step (3) is cooled to below 100℃.

[0010] In one embodiment, the temperature in step (4) is 60-80℃.

[0011] In one embodiment, steps (2) and (3) are replaced by connecting the mechanical stirring, thermometer, condenser tube and nitrogen device to the four-necked flask, and then adding weighed neopentyl glycol, phthalic anhydride, adipic acid, isophthalic acid-5-sodium sulfonate, trimethylolpropane and p-toluene sulfonic acid, warming to a certain temperature, and cooling to obtain a white emulsion.

[0012] In one embodiment, the warming method is: warming at 145-155℃ for 1 hour, warming at 165-175℃ for 1 hour, and warming at 185-195℃ for 1 hour.

[0013] The beneficial effects of the present application are: (1) The application adopts a suitable formula, and a prepolymerization-polymerization two-step method is adopted to synthesize the water-based polyester matrix, the weight ratio of isophthalic acid-5-sodium sulfonate and neopentyl glycol is controlled, the reaction conditions can be better controlled, and the dispersibility, stability, water resistance, heat resistance and other mechanical properties of the obtained coating are improved compared with the properties of the coating obtained by one-step synthesis; (2) The isophthalic acid-5-sodium sulfonate used in the application is a water-based monomer, which is a very strong monomer, and can give the resin stronger water solubility, and has a great influence on the water solubility of the polyester resin. When the amount is too high, the system gels, which is not conducive to the reaction; when the amount is too small, the water solubility of the resin is poor, and the stability is poor; the application controls the amount of isophthalic acid-5-sodium sulfonate, and the obtained resin has strong water dispersing ability and high stability of the polyester water dispersion. DETAILED DESCRIPTION

[0014] Example 1 A preparation method of a water-based polyester insulation coating for a new energy automobile aluminum shell battery cell, comprising the following steps: (1) The following components are weighed: neopentyl glycol 35g, phthalic anhydride 20g, adipic acid 20g, isophthalic acid-5-sodium sulfonate 15g, trimethylolpropane 9g, p-toluenesulfonic acid 1g; (2) 15g of isophthalic acid-5-sodium sulfonate, 15g of neopentyl glycol and 60ml of water are uniformly mixed, and are added into a four-necked flask with mechanical stirring, a thermometer, a condenser tube and a nitrogen device, stirring is started, heating and temperature rising to 150 DEG C are carried out, and prepolymers are obtained by keeping warm until white non-melting material disappears; (3) The remaining 20g of neopentyl glycol, 20g of phthalic anhydride, 20g of adipic acid, 9g of trimethylolpropane and 1g of p-toluenesulfonic acid are sequentially added into the prepolymers, 150 DEG C is kept for 1 hour, 170 DEG C is kept for 1 hour, 190 DEG C is kept for 1 hour, and the temperature is reduced to below 100 DEG C to obtain a polyester water dispersion; (4) 10g of the polyester water dispersion is weighed, deionized water is added, stirring is carried out at a temperature of 70 DEG C, and then standing is carried out to obtain a water-based polyester dispersion; (5) The polyester water dispersion is added into a curing agent, a catalyst, a pigment, a filler, a cosolvent, and a water-based polyester insulation coating is obtained by mixing.

[0015] Example 2 A preparation method of a water-based polyester insulation coating for a new energy automobile aluminum shell battery cell, comprising the following steps: (1) The following components are weighed: neopentyl glycol 30g, phthalic anhydride 25g, adipic acid 25g, isophthalic acid-5-sodium sulfonate 10g, trimethylolpropane 9g, p-toluenesulfonic acid 1g; (2) 10 g of sodium 5-sulfoisophthalate, 20 g of neopentyl glycol and 60 ml of water were mixed uniformly and added into a four-necked flask with mechanical stirring, a thermometer, a condenser tube and a nitrogen device. The stirring was started and the temperature was raised to 155°C. The pre-polymer was obtained after the white insoluble matter disappeared; (3) The remaining 10 g of neopentyl glycol, 25 g of phthalic anhydride, 25 g of adipic acid, 9 g of trimethylolpropane and 1 g of p-toluenesulfonic acid were sequentially added into the pre-polymer. The temperature was kept at 155°C for 1 hour, at 175°C for 1 hour and at 190°C for 1 hour. The temperature was then lowered to below 100°C to obtain a water dispersion of the polyester; (4) 10 g of the water dispersion of the polyester was weighed and added into deionized water. The mixture was stirred at a temperature of 70°C and then left to stand to obtain a water-based polyester dispersion; (5) The water-based polyester dispersion was added into a curing agent, a catalyst, a pigment, a filler and a cosolvent. The mixture was mixed to obtain a water-based polyester insulating coating.

[0016] Example 3 A preparation method of a water-based polyester insulating coating for an aluminum shell battery cell of a new energy vehicle, comprising the following steps: (1) The following components were weighed: neopentyl glycol 35 g, phthalic anhydride 20 g, adipic acid 20 g, sodium 5-sulfoisophthalate 15 g, trimethylolpropane 9 g and p-toluenesulfonic acid 1 g; (2) 15 g of sodium 5-sulfoisophthalate, 15 g of neopentyl glycol and 60 ml of water were mixed uniformly and added into a four-necked flask with mechanical stirring, a thermometer, a condenser tube and a nitrogen device. The stirring was started and the temperature was raised to 150°C. The pre-polymer was obtained after the white insoluble matter disappeared; (3) The remaining 20 g of neopentyl glycol, 20 g of phthalic anhydride, 20 g of adipic acid, 9 g of trimethylolpropane and 1 g of p-toluenesulfonic acid were sequentially added into the pre-polymer. The temperature was kept at 145°C for 1 hour, at 180°C for 1 hour and at 195°C for 1 hour. The temperature was then lowered to below 100°C to obtain a water dispersion of the polyester; (4) 10 g of the water dispersion of the polyester was weighed and added into deionized water. The mixture was stirred at a temperature of 70°C and then left to stand to obtain a water-based polyester dispersion; (5) The water-based polyester dispersion was added into a curing agent, a catalyst, a pigment, a filler and a cosolvent. The mixture was mixed to obtain a water-based polyester insulating coating.

[0017] Comparative Example 1 A preparation method of a water-based polyester insulating coating for an aluminum shell battery cell of a new energy vehicle, comprising the following steps: (1) The following components were weighed: neopentyl glycol 30 g, phthalic anhydride 20 g, adipic acid 20 g, sodium 5-sulfoisophthalate 23 g, trimethylolpropane 6 g and p-toluenesulfonic acid 1 g; (2) 23 g of sodium 5-sulfoisophthalate, 23 g of neopentyl glycol and 92 ml of water were mixed uniformly and added into a four-necked flask with mechanical stirring, a thermometer, a condenser tube and a nitrogen device, stirring was started, heating and temperature rising to 150°C, and the pre-polymer was obtained after the white insoluble matter disappeared; (3) The remaining 7 g of neopentyl glycol, 20 g of phthalic anhydride, 20 g of adipic acid, 6 g of trimethylolpropane and 1 g of p-toluenesulfonic acid were sequentially added into the pre-polymer, and the temperature was kept at 150°C for 1 hour, 170°C for 1 hour and 190°C for 1 hour, and then the temperature was reduced to below 100°C to obtain a water dispersion of polyester; (4) 10 g of the water dispersion of polyester was weighed and added into deionized water, and then stirred at a temperature of 70°C, and then the water-based polyester dispersion was obtained after standing; (5) The water-based polyester dispersion was added into a curing agent, a catalyst, a pigment, a filler and a cosolvent, and then mixed to obtain a water-based polyester insulating coating.

[0018] Comparative Example 2 A preparation method of a water-based polyester insulating coating for a new energy automobile aluminum shell battery cell, comprising the following steps: (1) The following components were weighed: neopentyl glycol 35 g, phthalic anhydride 20 g, adipic acid 20 g, sodium 5-sulfoisophthalate 15 g, trimethylolpropane 9 g, and p-toluenesulfonic acid 1 g; (2) 15 g of sodium 5-sulfoisophthalate, 35 g of neopentyl glycol and 60 ml of water were mixed uniformly and added into a four-necked flask with mechanical stirring, a thermometer, a condenser tube and a nitrogen device, stirring was started, heating and temperature rising to 150°C, and the pre-polymer was obtained after the white insoluble matter disappeared; (3) 20 g of phthalic anhydride, 20 g of adipic acid, 9 g of trimethylolpropane and 1 g of p-toluenesulfonic acid were sequentially added into the pre-polymer, and the temperature was kept at 150°C for 1 hour, 170°C for 1 hour and 190°C for 1 hour, and then the temperature was reduced to below 100°C to obtain a water dispersion of polyester; (4) 10 g of the water dispersion of polyester was weighed and added into deionized water, and then stirred at a temperature of 70°C, and then the water-based polyester dispersion was obtained after standing; (5) The water-based polyester dispersion was added into a curing agent, a catalyst, a pigment, a filler and a cosolvent, and then mixed to obtain a water-based polyester insulating coating.

[0019] Comparative Example 3 A preparation method of a water-based polyester insulating coating for a new energy automobile aluminum shell battery cell, comprising the following steps: (1) The following components were weighed: neopentyl glycol 35 g, phthalic anhydride 20 g, adipic acid 20 g, sodium 5-sulfoisophthalate 15 g, trimethylolpropane 9 g, and p-toluenesulfonic acid 1 g; (2) connect the mechanical stirring, thermometer, condenser, nitrogen device with four opening bottle closely, then add weighed neopentyl glycol 35 g, phthalic anhydride 20 g, adipic acid 20 g, isophthalic acid-5-sodium sulfonate 15 g, trimethylolpropane 9 g and p-toluene sulfonic acid 1 g, heat and warm up to 150 DEG C, keep warm for 1 hour, keep warm at 170 DEG C for 1 hour, keep warm at 190 DEG C for 1 hour, cool down to 100 DEG C, get white emulsion by cooling down; (3) weigh 10 g of the polyester water dispersion, add deionized water, stir at 70 DEG C, then stand, get water-based polyester dispersion; (4) add curing agent, catalyst, pigment, filler, cosolvent to the polyester water dispersion, mix to get water-based polyester insulating coating.

[0020] The appearance detection method of paint film is visual inspection; The adhesion detection method is GB 1720-79; The water resistance detection method is 60 h in water; The high temperature resistance detection method is GB / T 1735-1979 (1989); The acid and alkali corrosion resistance detection method is GB / T 8077-2008; The breakdown strength determination method is HG / T 3330-1980 (1985).

[0021] Table 1 performance test results

[0022] From the results in Table 1, examples 1-3 are water-based polyester insulating coatings prepared according to the formulation and preparation method of the present application, and the performances meet the requirements.

[0023] Comparative example 1 adds more isophthalic acid-5-sodium sulfonate, the system gels, which is not conducive to the reaction, the leveling of the paint film is slightly poor, and the performances are slightly decreased.

[0024] Comparative example 2 adds isophthalic acid-5-sodium sulfonate in step (2) in a mass ratio not within 1:1-2 to neopentyl glycol, the reaction conditions are changed, and the performances of the paint film are slightly decreased.

[0025] Comparative example 3 uses one-step synthesis method to obtain polyester water dispersion, and the performances of the paint film are slightly decreased.

[0026] Those skilled in the art should understand that the above discussion of any embodiment is only intended to be illustrative and is not intended to be limiting to the scope of the present application; the above embodiments or technical features among different embodiments can also be combined, the steps can be implemented in any order, and there are many other changes such as the different aspects of one or more embodiments of the present application as described above, which are not provided in details for the sake of brevity.

[0027] One or more embodiments of the present application are intended to cover all such alternatives, modifications, and variations as fall within the broad scope of the present application. Accordingly, any one of the above-cited examples, or any other unrecited example, can be omitted, modified, or substituted, or any combination of the above-cited examples, or any other unrecited example, can be combined, in any order, and any omission, modification, substitution, or combination of the above-cited examples, or any other unrecited example, that is within the spirit and principle of one or more embodiments of the present application, shall be included within the scope of the present application.

Claims

1. A method for preparing a water-based polyester insulating coating for aluminum shell batteries of new energy vehicles, characterized in that: The steps include: (1) Weigh the following components in percentage by weight: 30-40% neopentyl glycol, 20-30% phthalic anhydride, 20-30% adipic acid, 10-20% sodium 5-sulfoisophthalate, 6-16% trimethylolpropane, and 0.5-1.5% p-toluenesulfonic acid; (2) Sodium 5-sulfoisophthalate and part of neopentyl glycol are mixed uniformly in a certain proportion and a certain amount of water, and added into a four-necked flask equipped with a mechanical stirrer, a thermometer, a condenser, and a nitrogen device. Stirring is started, and heating is continued until the white infusible material disappears to obtain a prepolymer; (3) adding the remaining neopentyl glycol, adipic acid, phthalic anhydride, trimethylolpropane and p-toluenesulfonic acid to the prepolymer in sequence, heating the mixture to a certain temperature, and then cooling the mixture to obtain a polyester aqueous dispersion; (4) Weighing a certain amount of polyester aqueous dispersion, adding deionized water, stirring at a certain temperature, and then letting it stand to obtain an aqueous polyester dispersion; (5) Adding a curing agent, a catalyst, a pigment, a filler, and a cosolvent to the polyester aqueous dispersion and mixing them to obtain a water-based polyester insulating coating.

2. The method for preparing the water-based polyester insulating coating for the aluminum shell battery core of the new energy vehicle according to claim 1, characterized in that: In the step (2), the weight ratio of 5-sodium sulfophthalate and neopentyl glycol added is 1:1-2.

3. The method for preparing the water-based polyester insulating coating for the aluminum shell battery core of the new energy vehicle according to claim 1, characterized in that: The amount of water added in step (2) is 2-3 times the sum of the amounts of 5-sodium sulfoisophthalate and neopentyl glycol added.

4. The method for preparing the water-based polyester insulating coating for the aluminum shell battery core of the new energy vehicle according to claim 1, characterized in that: In the step (2), the temperature is raised to 145-155°C.

5. The method for preparing the water-based polyester insulating coating for the aluminum shell battery core of the new energy vehicle according to claim 1, characterized in that: The heating method in step (3) is: keeping warm at 145-155°C for 1 hour, keeping warm at 165-175°C for 1 hour, and keeping warm at 185-195°C for 1 hour.

6. The method for preparing the water-based polyester insulating coating for the aluminum shell battery core of the new energy vehicle according to claim 1, characterized in that: In the step (3), the temperature is lowered to below 100°C.

7. The method for preparing the water-based polyester insulating coating for the aluminum shell battery core of the new energy vehicle according to claim 1, characterized in that: The certain temperature in step (4) is 60-80°C.

8. The method for preparing the water-based polyester insulating coating for the aluminum shell battery core of the new energy vehicle according to claim 1, characterized in that: The steps (2) and (3) are replaced by tightly connecting a mechanical stirrer, a thermometer, a condenser, and a nitrogen device to a four-necked flask, and then adding weighed neopentyl glycol, phthalic anhydride, adipic acid, sodium 5-sulfonate diformate, trimethylolpropane, and p-toluenesulfonic acid, heating to a certain temperature, and then cooling to obtain a white emulsion.

9. The method for preparing a water-based polyester insulating coating for an aluminum shell battery core of a new energy vehicle according to claim 8, wherein: The heating method comprises the steps of: keeping the temperature at 145-155° C. for 1 hour, keeping the temperature at 165-175° C. for 1 hour, and keeping the temperature at 185-195° C. for 1 hour.

10. The method for preparing a water-based polyester insulating coating for aluminum shell batteries of new energy vehicles according to claim 8, characterized in that: The temperature is lowered to below 100°C.

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