New energy vehicle battery pack normal temperature curing protective environment-friendly flame-retardant water-based coating

Abstract

The present application belongs to the technical field of battery pack surface protection coating for automobiles, and particularly relates to a new energy vehicle battery pack normal temperature curing protection environment-friendly flame-retardant water-based coating. The coating is prepared by proportioning, and includes 40-45 parts of self-prepared acrylic emulsion PK-1220, 30-34 parts of 400 mesh aluminum hydroxide, 9-11 parts of wollastonite, 4-6 parts of expanded graphite, 1-2 parts of wood fiber, 0.1-0.2 parts of thickening agent, 0.3-0.5 parts of dispersing agent, 0.2-0.3 parts of bactericide, and 0.5-1 parts of film-forming aid. The high environment-friendly flame-retardant water-based coating has protection and stone impact resistance functions, improves the safety of the battery pack or oil tank during driving, can reduce the noise in the vehicle, especially when on fire, can protect the safety of passengers and external personnel, and avoid property loss.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of battery pack surface protection coating for automobiles, and particularly relates to a normal-temperature curing environmental protection flame-retardant water-based coating for battery pack of new energy vehicle. BACKGROUND

[0002] In recent years, with the rapid development of China's manufacturing industry, China's automobile industry has ushered in new opportunities and occupies a position in the global automobile field, so the safety of automobile related components is also a top priority, especially the protection of battery pack and fuel tank shell of passenger cars including new energy vehicle models. The traditional solution is to use PVC coating to spray the surface, and then cure it at high temperature (130-150 DEG C) to make the surface have certain adhesion and other protection requirements. Although it has corresponding advantages, the disadvantages are also obvious, especially the flame retardant performance cannot be well reflected, and there is a strong odor after high temperature baking. The VOC also needs to be improved. The normal-temperature curing environmental protection flame-retardant water-based coating for battery pack of new energy vehicle provided by the present application not only can achieve high-strength flame retardation, but also can achieve normal-temperature curing, without other odor during construction and use, and the VOC can meet the European Union standard, and can meet the relevant technical requirements of vehicle enterprises in terms of stone chip resistance and adhesion. SUMMARY

[0003] In order to solve the above-mentioned technical problems, the purpose of the present application is to invent a water-based coating which can achieve normal-temperature curing, reduce VOC, and has high flame retardant performance. Because it is used on the surface of battery pack, fuel tank surface and fuel tank outer surface, it has strong flame retardant effect, and can meet the environmental protection requirements under the premise of considering this function.

[0004] The present application uses ultra-fine aluminum hydroxide as the main flame retardant material, and uses 400 mesh aluminum hydroxide. After normal-temperature curing, it has very high flame retardant and smoke suppression performance, and can also achieve lightweight. As an inorganic flame retardant, it does not contain halogen, phosphorus and other harmful elements, and the price is relatively low. Moreover, aluminum hydroxide can improve the mechanical strength and impact resistance of the product. Because the particle size is uniform, it can not only improve the processing fluidity, but also make the construction surface more smooth.

[0005] And also use acicular wollastonite for filling, which can form a reinforced network, significantly improve the tensile strength, bending strength and impact strength of the coating, and also can reduce the shrinkage rate, thereby increasing the durability. In order to improve the flame retardant performance, expanded graphite and wood fiber are added to the product. The flexible graphite material maintains excellent sealing performance in the range of-200 DEG C-450 DEG C, and can form a heat insulation expansion layer under its action. The added wood fiber can realize a porous structure and fast curing.

[0006] The synthetic acrylic emulsion of methyl methacrylate, lauryl acrylate, halogen monofunctional acrylic monomer (SW-513) and glycidyl methacrylate (GMA) etc. used in the application is combined, and bio-based alcohol is added therein to improve film forming performance and environmental protection, becoming a water-based polymer system, wherein the methyl methacrylate has a higher glass transition temperature of about 100℃ due to containing methyl and benzene ring, and can improve the strength of the resin, the TG value of lauryl acrylate is -6 / -30, and the lauryl acrylate has flexibility, impact resistance, adhesion and good leveling, and the structural strength thereof in use is improved. At the same time, the halogen monofunctional acrylic monomer and glycidyl methacrylate (GMA) can realize good product flame retardance, weather resistance, film forming property and weather resistance etc.

[0007] To achieve the above-mentioned purpose, the technical scheme adopted by the application is: a new energy vehicle battery pack normal temperature curing protection environment-friendly flame-retardant water-based coating, the water-based coating is proportioned by parts, including acrylic emulsion 40-45 parts, 400 mesh aluminum hydroxide 30-34 parts, wollastonite 9-11 parts, expanded graphite 4-6 parts, wood fiber 1-2 parts, thickening agent 0.1-0.2 parts, dispersant 0.3-0.5 parts, bactericide 0.2-0.3 parts, and C-12 film forming aid 0.5-1 part.

[0008] The acrylic emulsion is named as PK-1220, and the raw materials are methyl methacrylate, lauryl acrylate, halogen monofunctional acrylic monomer (SW-513) and glycidyl methacrylate (GMA), water, sodium dodecyl diphenyl ether disulfonate, azobisdimethylimidazole hydrochloride (VA-044 initiator), the glass transition temperature Tg of the acrylic emulsion is 45℃, wherein the glass transition temperature of the methyl methacrylate is 104-105℃, the decomposition temperature is not more than 270℃, the flow temperature is about 160℃, the glass transition temperature of the lauryl acrylate is -30℃, the lauryl acrylate is a soft monomer and enhances flexibility, and the glass transition temperature of the glycidyl methacrylate (GMA) is 40℃, the high Tg GMA can improve the impact resistance of the coating, the preparation method is simple, the monomer, initiator and emulsifier are first stirred and emulsified into an emulsion in the emulsification tank part, then water, emulsifier and bio-based alcohol (1,3 propanediol) are added to the reaction kettle and heated to a certain temperature, then the emulsifier and initiator are added dropwise into the reaction kettle, the time is generally 3 hours, and after 3 hours, the temperature is kept for 1-2 hours, and the PK-1220 is obtained.

[0009] The dispersant is a high-performance dispersant of BASF Efka Px4787, which can improve the resistance, and the solid content is 70%, and the active ingredient amine value is 15%.

[0010] The 400 mesh aluminum hydroxide can be from Jinan Zhengpin Chemical Co., Ltd., and the density is 2.42g / m 2Note that heating to 300°C decomposes into aluminum oxide and water.

[0011] Wollastonite is a single chain silicate mineral, using flaky 325 mesh, color white with grayish, hardness 4.5-5.0, density 2.78-2.91g / cm 3 , with good reinforcement, improve the toughness and durability of the product, get better mechanical strength, increase durability, enhance adhesion and corrosion resistance, the user is Jiangxi Kote.

[0012] The expanded graphite is abbreviated as EGP, which is a carbon type material obtained by treating natural graphite flake through chemical or physical intercalation, washing, drying, high temperature expansion and other processes, and is in the form of loose and porous vermicular worm, and the EGP used by us is obtained by acidizing treatment of graphite combined with concentrated sulfuric acid, concentrated nitric acid and other chemical reagents, washing, drying and high temperature expansion, and the manufacturer is Jiangsu Xianfeng Nanometer Material Science and Technology.

[0013] Wood fiber TMS-800 can form a three-dimensional space structure in the material, adsorb 6-8 times of moisture of self weight, also plays a role of heat preservation and crack resistance, improves surface strength and bonding strength, and the manufacturer is also Bo Chemical Industry.

[0014] ASE-60 as a thickening agent does not contain cellulose, has strong antimicrobial ability, good long-term stability, can improve spatter resistance and anti-sagging property, and the manufacturer is Dongguan Yingke High-tech Material Co., Ltd.

[0015] C-12 film forming aid can improve the film forming property of emulsion and reduce the film forming temperature, has a melting point of -50 DEG C, is insoluble in water and soluble in organic solvents, and the manufacturer is Jinan Fangyi Chemical Industry.

[0016] The bactericide 2.5SF contains two active ingredients, is suitable for water-based systems, has low addition amount, and is stable within the range of PH 4-9, and the manufacturer is Langfang Zhengchi New Material.

[0017] The high environmental protection fire-retardant water-based coating has the beneficial effects that, compared with traditional technologies:

[0018] 1. The environmental protection fire-retardant water-based coating has the protection and stone impact resistance functions of traditional PVC coatings, improves the safety of battery packs or oil tanks during driving, can reduce the noise in the vehicle, especially when on fire, because the oil tank and the battery pack are both flammable and explosive components, so it is inevitable to improve the fire-retardant property, can protect the safety of passengers and external personnel, and avoid property loss.

[0019] 2、The self-prepared PK-1220 acrylic emulsion of the application has the following advantages: firstly, the acoustic performance is outstanding, can effectively absorb and insulate noise, and the formed coating or material can improve the sound insulation effect by more than 30%, although noise absorption and insulation are not the main aspects we focus on, but also beneficial; in addition, it has good damping performance, optimizing the sound insulation effect; the third point is that the self-prepared emulsion has excellent anti-aging and water resistance, and remains stable in outdoor or humid environment, with a service life of more than ten years; and has excellent environmental protection characteristics, because of the addition of bio-based alcohol, improves the film forming property, reduces VOC and waste glue recyclability, and can improve the adhesion strength and stability in combination with related fillers.

[0020] 3、The acidified expanded graphite, aluminum hydroxide and wollastonite used in the product can achieve the designed high environmental protection and flame retardation, and can be applied to the surface of battery pack and oil tank to reduce the high risk, and the surface is loose and porous, the internal moisture volatilizes, the solidification time is reduced, the construction efficiency is improved, and excellent toughness is also considered. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 is the working principle diagram of the environmentally friendly flame-retardant water-based coating prepared in Example 1.

[0022] Figure 2 is the anti-stone impact test diagram; wherein A is the sample diagram after the anti-stone impact test, and B is the sample diagram after the impact resistance test.

[0023] Figure 3 is the battery protection diagram of the environmentally friendly flame-retardant water-based coating prepared in Example 1, wherein 1 is a shell, 2 is a second skeleton, 3 is a battery core, and 4 is a first skeleton.

[0024] Figure 4 is the top view of the battery and chassis.

[0025] Figure 5 is the damping and sound insulation performance comparison diagram. DETAILED DESCRIPTION

[0026] The application will be described in detail below in combination with examples.

[0027] Example 1: An environmentally friendly flame-retardant water-based coating for a new energy vehicle battery pack at room temperature

[0028] (I) The formula composition is as follows

[0029] 45g PK-1220 (self-prepared acrylic emulsion), 34g aluminum hydroxide, 11g wollastonite, 6g expanded graphite, 2g wood fiber, 0.2g thickening agent ASE-60, 0.5g dispersant BASF Efka Px4787, 0.3g bactericide 2.5SF, 1g film forming aid C-12.

[0030] (II) Preparation method as follows:

[0031] 1. Preparation method of self-prepared acrylic emulsion PK-1220: 33 g of methyl methacrylate, 12 g of lauryl acrylate, 2.5 g of halogen monomer SW-513, and 4 g of glycidyl methacrylate GMA are stirred and emulsified into an emulsion, 45 g of water, 3 g of bio-based alcohol (1,3-propanediol), 8.5 g of emulsifier (sodium dodecyl diphenyl ether disulfonate) are added, and the temperature is raised to 50-70°C, then 2 g of initiator azobisimidozoline hydrochloride (VA-044 initiator) is added dropwise into the reaction kettle, the time is 3 hours, and after 3 hours, it is kept for 1-2 hours, to obtain acrylic emulsion PK-1220.

[0032] 2. The preparation method of bio-based alcohol is glucose fermentation method. Glucose is first converted into pyruvic acid through glycolysis pathway, and then glycerol is generated through reaction. Under the action of glycerol dehydrase and 1,3-propanediol oxidoreductase, 1,3-propanediol is converted into 1,3-propanediol. The reaction process is as follows.

[0033]

[0034] 3. According to the environment, the circulating water is started, and the above-mentioned 45 g of self-prepared acrylic emulsion PK-1220 is put into the reaction kettle (-0.08 MPa suction), and the stirring is started, and the stirring is started at low speed (30 r / min), and the stirring is started at high speed (300 r / min), and the stirring is started for 2 minutes, and the temperature reaches 20-23°C.

[0035] 4. Start stirring at a speed of 30 r / min, mix 34 g of aluminum hydroxide, 11 g of wollastonite, and 6 g of expanded graphite, and then put them into the reaction kettle in 5 times, with an interval of 30 seconds each time. After all the materials are put in, stir for 3 minutes.

[0036] 5. Start stirring at a speed of 30 r / min, then start stirring at a speed of 300 r / min, and start circulating at a speed of 30 r / min, then put in 2 g of wood fiber, and then start stirring at a low speed (30 r / min) for 5 minutes.

[0037] 6. Start stirring at a speed of 30 r / min, slowly put in 0.5 g of dispersant BASF Efka Px4787, then start stirring at a low speed (30 r / min), and start stirring at a high speed (600 r / min), and start circulating at a speed of 30 r / min for 10 minutes.

[0038] 7. Start low speed stirring (30 r / min), put in 0.3 g of bactericide 2.5 SF and 1 g of film forming aid C-12, then start low speed stirring (30 r / min) and high speed stirring (600 r / min) and start circulation (30 r / min) for 10 minutes.

[0039] 8. Take sample and test its BH viscosity.

[0040] 9. According to the viscosity result, whether it is in the range of 45000-65000 Pa.S, if not in the above range, 0.2 g of thickening agent ASE-60 is needed, start low speed stirring (30 r / min) and high speed stirring (600 r / min), and start circulation (30 r / min), vacuum defoaming -0.05 Mpa, 2 min→0.08 Mpa, 10 min. (Warm the gun to measure the temperature, the temperature should not exceed 30℃, if it exceeds, immediately start the cooling circulating water).

[0041] 10. Take sample and test its 100 grid test adhesion, the result should be ≤2 level to be qualified.

[0042] 11. Filter twice with 20 mesh and 30 mesh and package.

[0043] Figure 1 is the use position of the product, the above prepared environmentally friendly flame-retardant water-based coating is sprayed on the surface of the shell of the battery core to realize the anti-stone impact and flame-retardant protection function.

[0044] Figure 3 is a battery protection diagram, 3 is a battery core, 4 is a first skeleton, 2 is a second skeleton, and 1 is a shell. The above prepared environmentally friendly flame-retardant water-based coating is sprayed on the surface of the shell 1, and through normal temperature curing, a 1-2 mm flame-retardant protection layer is formed on the surface to protect the battery shell from being damaged.

[0045] Figure 4 is a bottom view of the battery, and also to more clearly and intuitively view the use position and the importance of the environmentally friendly flame-retardant water-based coating for automobile protection.

[0046] Example 2

[0047] According to the weight ratio, 45 g of Wanhua emulsion 0656B is used, and other components remain unchanged as in Example 1. The trade names and manufacturers of each component are the same as in Example 1, and the self-prepared acrylic emulsion is also described.

[0048] Comparative Example

[0049] 1. Comparative Example 1

[0050] 400 mesh calcium carbonate is used to replace aluminum hydroxide in Example 1, and other components and proportions remain unchanged.

[0051] 2. Comparative Example 2

[0052] The water-based polyurethane emulsion with a glass transition temperature of 50°C was used instead of PK-1220 emulsion in Example 1, and other components and proportions were unchanged.

[0053] 3. Comparative Example 3

[0054] The ordinary graphite (particle size 1 um-500 um, 75% of the oversize) was used instead of expanded graphite in Example 1, and other components and proportions were unchanged.

[0055] 4. Comparative Example 4

[0056] Commercially available PVC coating used by automobile manufacturers.

[0057] Performance test of Example 3

[0058] (1) The specific test technical indicators are shown in Table 1:

[0059] Table 1 Comparison of coating performance of examples and comparative examples

[0060]

[0061] As can be seen from Table 1, the flame retardant performance of Comparative Example 1 using calcium carbonate decreases, the adhesion is poor, the safety is reduced, and the flame retardant performance far cannot meet the requirements and standards designed in the application.

[0062] Example 2 uses other acrylic emulsion, and the dry time exceeds the expected time, and the effect does not reach the ideal state.

[0063] Comparative Example 2 uses water-based polyurethane emulsion with little difference in glass transition temperature, which has flame retardant effect to some extent, but has strong odor, and the curing time is prolonged, deviating from the original intention of normal temperature curing, the odor is not pleasant, and the adhesion cannot meet the corresponding technical standards.

[0064] Comparative Example 3 has little difference in the body, but the water-based coating of ordinary graphite has poor sagging property, which is easy to cause flowing during construction and spraying, affecting the quality of the whole vehicle.

[0065] Comparative Example 4 has good flexibility when used, but has strong odor after high temperature baking, V0C does not meet the standard, and the flame retardant property is poorer than Example.

[0066] (2) Damping coefficient test

[0067] The damping coefficient test method is as follows: a wet film 3mm damping sample of size 210±0.5mm x 10±0.5mm is prepared on a steel plate of size (240±0.3mm x 10±0.3mm x 1±0.02mm) for a vehicle body, the sample is placed at room temperature for 48h and then clamped to a cantilever beam damping measuring instrument, the test frequency is (50-5000)HZ, and the corresponding damping coefficient is recorded at temperatures of 0°C, 20°C, 40°C and 60°C (each temperature is kept constant for 10min before measurement), and the second resonance peak data near 200HZ is read.

[0068] Table 2 Example and Comparative Example Damping and Sound Insulation Performance Test Data

[0069]

[0070] As can be seen from Table 2, under the same conditions, the inventive product has better sound insulation and damping performance, and passes the Figure 5 The value can also be analyzed to be the maximum.

[0071] (II) Stone Chip Resistance Test and Impact Resistance Test

[0072] Figure 2 The stone chip resistance test is carried out in the laboratory, using a dry film 500u, SAE J400 fly stone method, pressure 0.049Mpa, 5 tests, the impact picture is shown in Figure 2 A, no cracking, peeling phenomenon, meets the expected functional design.

[0073] Figure 2 B is the sample after the impact resistance test, 50kg.cm impact without cracks, peeling.

Claims

1. A new energy vehicle battery pack normal temperature curing protective environmental protection flame-retardant water-based coating, characterized in that, The amount of proportioning, including self-proportioning acrylic emulsion PK-1220 40-45 parts, 400 mesh aluminum hydroxide 30-34 parts, wollastonite 9-11 parts, expanded graphite 4-6 parts, wood fiber 1-2 parts, thickening agent 0.1-0.2 parts, dispersing agent 0.3-0.5 parts, fungicide 0.2-0.3 parts, film forming aid 0.5-1 parts; the preparation method of the self-proportioning acrylic emulsion PK-1220 is as follows: methyl methacrylate, lauryl acrylate, halogen monofunctional acrylic monomer SW-513 and glycidyl methacrylate are stirred and emulsified into emulsion, water, bio-based alcohol, emulsifier sodium dodecyl diphenyl ether disulfonate are added, the temperature is raised to 50-70℃, initiator azobisimidozoline hydrochloride is added dropwise, the time is 3 hours, after 3 hours, keep warm for 1-2 hours, get acrylic emulsion PK-1220; the bio-based alcohol is 1,3-propanediol, the preparation method is glucose fermentation method, glucose is first converted into pyruvic acid through glycolysis pathway, then glycerol is generated through reaction, and then 1,3-propanediol is converted into 1,3-propanediol through the action of glycerol dehydrase and 1,3-propanediol oxidoreductase.

2. The battery pack for new energy vehicles at room temperature according to claim 1, characterized in that, The dispersing agent is BASF Efka Px4787 high performance dispersing agent.

3. The battery pack for new energy vehicles at room temperature according to claim 1, characterized in that, The 400 mesh aluminum hydroxide has a density of 2.42 g / m 2 and a decomposition temperature of 300°C.

4. The battery pack for new energy vehicles at room temperature according to claim 1, characterized in that, The wollastonite is a single chain silicate mineral, flaky 325 mesh, hardness of 4.5-5.0, density of 2.78-2.91 g / cm 3 .

5. The battery pack for new energy vehicles at room temperature according to claim 1, characterized in that, The wood fiber is TMS-800.

6. The battery pack for new energy vehicles at room temperature according to claim 1, characterized in that, The thickening agent is ASE-60.

7. The battery pack for new energy vehicles at room temperature according to claim 1, characterized in that, The fungicide is 2.5SF.

Images