UV system battery insulating paint and preparation method thereof

Abstract

The invention relates to a UV system battery insulation coating and a preparation method thereof, and the UV system battery insulation coating is mainly prepared from the following components: special modified polyurethane acrylate, isobornyl methacrylate, epoxy acrylate, a dispersant, 2, 4, 6-trimethylbenzoyl-diphenyl phosphine oxide, benzoyl formate, phenyl bis 2, 4, 6-trimethylbenzoyl-diphenyl phosphine oxide, 2, 4, 6-trimethylbenzoyl-diphenyl phosphine oxide, 2, 4, 6-trimethylbenzoyl-diphenyl phosphine oxide, 2, 4, 6-trimethylbenzoyl-diphenyl phosphine oxide, 2, 4, 6- The coating is prepared from 2, 4, 6-trimethylbenzoyl phosphine oxide, a defoaming agent, a flatting agent and color paste. The invention overcomes the defects that the cell of the existing power battery mostly adopts a PET (Polyethylene Terephthalate) blue film, has weak adhesive property, is easy to fall off and strip and the like, and adopts special modified polyurethane acrylate, epoxy acrylate and isobornyl methacrylate, and is matched with two preferably selected photoinitiators capable of efficiently absorbing near 395nm and a photoinitiator with high odor removal property; and under the synergistic effect with other components with preferable types and dosage proportions in the system, the adhesive has the advantages of excellent cohesiveness, ageing resistance, adhesive force, insulation, pressure resistance and impact resistance.

Description

Technical Field

[0001] The invention relates to a UV system battery insulating coating and a preparation method thereof, and is applied in the field of battery insulating coating product production. Background Art

[0002] In order to ensure electrical safety, the cells of power batteries have always needed to be wrapped with PET "blue film", but with the substantial increase in working voltage and energy density, this insulation solution has begun to fall behind. Recently, many new energy giants, led by BMW, have begun to turn to a new UV insulation coating solution, which is expected to trigger a new round of upgrades in power battery insulation solutions. The so-called "blue film" is a single-sided tape made of PSA pressure-sensitive adhesive on the back of a PET substrate. Because this type of product is mostly dark blue, it is simply called "blue film". Since this film not only has good insulation properties, but also has good chemical resistance and tensile strength, it has always been the most mainstream solution for power battery electrical insulation and physical protection applications, but its bonding performance is relatively weak. Nowadays, with the vigorous development of automobiles, the substantial voltage increase has greatly increased the probability of arcing or insulation breakdown between cells. At the same time, the consistency of battery system voltage is also facing greater challenges. If the "blue film" is still used, it is tantamount to burying a time bomb for the safety of power batteries. Because the blue film has weak adhesive properties, when the voltage is greatly increased, the PSA adhesive of the "blue film" will undergo cohesive failure, which may directly cause the "blue film" to fall off from the battery shell. The method proposed in the paper "Preparation and Performance Research of Insulating Powder Coatings" is at a disadvantage in terms of construction efficiency, adhesive properties, and dielectric strength of the powder coating.

[0003] Therefore, it is urgent to provide a UV system battery insulating coating and its preparation method which has excellent adhesion, anti-aging, adhesion, insulation voltage resistance, and impact resistance, can be constructed by UV inkjet, has a uniform and thin paint film, can be cured into a film in one time, and has low cost. Summary of the invention

[0004] In order to overcome the problems that the existing power battery cells mostly use PET blue film, which has weak bonding performance and is easy to fall off and peel off, and the insulating powder coating has the disadvantages of construction efficiency, bonding performance, dielectric strength, etc., the present invention provides a UV system battery insulating coating and a preparation method thereof, which adopts special modified polyurethane acrylate, epoxy acrylate, and isobornyl methacrylate, preferably with two photoinitiators with high absorption near 395nm and a high net odor photoinitiator, and synergizes with other preferred types and usage ratios of components in the system, has excellent bonding, anti-aging, adhesion, insulation withstand voltage, and impact resistance, and can be constructed by UV inkjet, the paint film is uniform and thin, can be cured into a film in one time, and has the advantages of low cost.

[0005] The technical solution of the present invention is as follows:

[0006] A UV system battery insulating coating is mainly prepared from the following components in the following weight proportions:

[0007]

[0008]

[0009] The UV system battery insulation coating of the present application is a new type of photocurable coating that can replace the original PET "blue film" and is suitable for power batteries (especially high voltage platform (800V) power batteries). It uses special modified polyurethane acrylate, epoxy acrylate, methacrylate isobornyl, and is preferably matched with two photoinitiators with high absorption near 395nm and high net odor photoinitiator, and synergistically with other preferred types and dosage ratios of components in the system, and has excellent bonding, anti-aging, adhesion, insulation withstand voltage, and impact resistance. It can be constructed by UV inkjet, the paint film is uniform and thin, and can be cured into a film at one time, and the cost is low. It has greater advantages in production efficiency, bonding performance, insulation performance and edge coverage performance than traditional PET "blue film", powder coating, epoxy resin coating, etc. Among them, 2,4,6-trimethylbenzoyl-diphenylphosphine oxide and phenyl bis 2,4,6-trimethylbenzoylphosphine oxide are deep initiators, both of which are photoinitiators with high absorption near 395nm. Benzoyl formate is a high-odor photoinitiator. The viscosity of the UV system battery insulation coating is 300-500mpa.S. It can be constructed by UV inkjet. The paint film is uniform and thin. There is no need to wait for the film formation time during construction. UV lamps are used for curing immediately. The construction efficiency is extremely high and the cost is low. Among them, the special modified polyurethane acrylate adds special functional groups of carboxyl and hydroxyl, and contains TMPTA (trimethylolpropane triacrylate). The group modification process is as follows: first, bisphenol A epoxy is semi-esterified with acrylic acid, and then phosphoric acid is used to esterify and graft some epoxy groups that are not open-loop to generate phosphoric acid-modified EA resin; the overall viscosity is low, the shrinkage is low, the acid value is slightly high, the hardness is high, the adhesion to the metal substrate is excellent, and the flexibility is taken into account. The sample is prepared using isobornyl methacrylate, which can make the UV system battery insulation coating have the characteristics of low viscosity and low shrinkage, and is conducive to improving adhesion. The photoinitiators with high absorption efficiency near 395nm (370-450nm, with the maximum absorption wave up to 450nm), 2,4,6-trimethylbenzoyl-diphenylphosphine oxide and phenyl bis-2,4,6-trimethylbenzoylphosphine oxide can quickly absorb light energy for transition, generate active free radicals, and initiate polymerization and cross-linking. In a popular sense, it means that the curing can be completed quickly without the light source energy being very high. The choice of high-odor photoinitiator benzoylformate has much lower odor after curing than traditional initiators. The absorption wavelength of the photolysis product of the combination of the three initiators can move to short waves, has a photobleaching effect, is conducive to ultraviolet light transmission, is suitable for the curing of colored thick coatings, has high curing efficiency, low odor, can reduce energy consumption to a certain extent, and has good yellowing resistance.The surface free energy of most metal oxide films is still higher than that of UV coatings, so UV coatings have better wetting effects on metal substrates than other coatings; UV coatings contain carboxyl and hydroxyl oligomers and active diluents, which form hydrogen bonds or chemical bonds with the surface of the metal substrate, greatly improving the adhesion between the coating and the metal coating. The combination of specially modified polyurethane acrylate and epoxy acrylate: Both have high functional groups, which makes the paint film extremely flexible and also has high hardness paint film performance; at the same time, the acid value of the two resins is slightly higher, and the adhesion to metal is excellent. Isobornyl methacrylate is used as an active diluent for the product, and its curing shrinkage is low, which has a positive impact on the adhesion of the product paint film. In order to conduct a quantitative horizontal comparison, the ASTM D1002 standard of the "White Paper" was used to conduct shear strength tests on four insulation schemes (the product of this case and traditional PET insulation film, epoxy resin coating, and powder coating) that had undergone -40℃~100℃ thermal shock and 85℃ / 85%RH aging. The overall bonding strength of the UV insulation coating generated by the UV system battery insulation coating in this case is the highest among the four insulation schemes, that is, under high voltage, its bonding strength is the best.

[0010] The UV system battery insulation coating also includes 0.1-10 parts of white carbon black.

[0011] The overall system cross-linking density of the product in this case is high, and adding a small amount of white carbon black can enhance the resistance value of the paint film.

[0012] The color paste is titanium cyan blue.

[0013] The choice of titanium blue is the color requirement for power battery coatings in the industry. It is possible to add no color or other colors.

[0014] The method for preparing the UV system battery insulating coating comprises the following steps performed in sequence:

[0015] (1) Start a stirrer, adjust the speed to 1000-1200 r / min, add special modified polyurethane acrylate, isobornyl methacrylate and epoxy acrylate into the stirrer, and disperse them uniformly;

[0016] (2) Maintaining the rotation speed at 1000-1200 r / min, continue to add dispersant, 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, benzoyl formate, phenyl bis-2,4,6-trimethylbenzoylphosphine oxide, defoamer and leveling agent, and disperse for 5-10 minutes;

[0017] (3) Adjust the speed to 1200-1500r / min, continue to add color paste, and disperse it until the fineness is ≤25μm and there is no oil shrinkage.

[0018] The preparation method of the UV system battery insulating coating of the present application has simple process and no VOC emission.

[0019] The method for preparing the UV system battery insulating coating also includes step (4): adjusting the rotation speed to 1000-1200 r / min, continuing to add white carbon black, and passing it through a 180-220 mesh sieve after it is evenly dispersed.

[0020] Adding a small amount of white carbon black can further enhance the resistance value of the paint film.

[0021] Compared with the prior art, the present invention has the following advantages:

[0022] 1) The UV system battery insulating coating of the present application adopts special modified polyurethane acrylate, epoxy acrylate, and isobornyl methacrylate, preferably with two photoinitiators with high absorption near 395nm and a high net odor photoinitiator, and synergistically with other preferred types and usage ratios of components in the system, and has excellent bonding, anti-aging, adhesion, insulation withstand voltage, and impact resistance, and can be constructed by UV inkjet, the paint film is uniform and thin, can be cured into a film in one time, and has the advantages of low cost;

[0023] 2) The construction performance, edge coating performance, adhesion, dielectric strength and impact resistance of the UV system battery insulation coating product are better than other coatings (including traditional PET insulation film, epoxy resin coating and powder coating);

[0024] 3) The UV system battery insulation coating has a deodorizing effect;

[0025] 4) The preparation method of the UV system battery insulating coating is simple in process and has no VOC emission. DETAILED DESCRIPTION

[0026] The technical solution of the present invention will be clearly and completely described below in conjunction with specific embodiments.

[0027] Example 1

[0028] The UV system battery insulating coating of the present invention is mainly prepared from the following components in the following weight proportions:

[0029]

[0030] The color paste is titanium cyan blue.

[0031] The method for preparing the UV system battery insulating coating comprises the following steps performed in sequence:

[0032] (1) Start the mixer and adjust the speed to 1100 r / min. Add special modified polyurethane acrylate, isobornyl methacrylate and epoxy acrylate into the mixer and disperse them evenly.

[0033] (2) Maintaining the rotation speed at 1100 r / min, continue to add dispersant, 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, benzoyl formate, phenyl bis-2,4,6-trimethylbenzoylphosphine oxide, defoamer and leveling agent, and disperse for 8 minutes;

[0034] (3) Adjust the speed to 1300r / min and continue to add color paste until the fineness is ≤25μm and there is no oil shrinkage.

[0035] Example 2

[0036] The UV system battery insulating coating of the present invention is mainly prepared from the following components in the following weight proportions:

[0037]

[0038] The color paste is titanium cyan blue.

[0039] The method for preparing the UV system battery insulating coating comprises the following steps performed in sequence:

[0040] (1) starting a stirrer, adjusting the speed to 1000 r / min, adding specially modified polyurethane acrylate, isobornyl methacrylate and epoxy acrylate into the stirrer, and dispersing them uniformly;

[0041] (2) Maintaining the rotation speed at 1000 r / min, continue to add dispersant, 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, benzoyl formate, phenyl bis-2,4,6-trimethylbenzoylphosphine oxide, defoamer and leveling agent, and disperse for 10 minutes;

[0042] (3) Adjust the speed to 1200r / min and continue to add color paste until the fineness is ≤25μm and there is no oil shrinkage.

[0043] Example 3

[0044] The UV system battery insulating coating of the present invention is mainly prepared from the following components in the following weight proportions:

[0045]

[0046] The color paste is titanium cyan blue.

[0047] The method for preparing the UV system battery insulating coating comprises the following steps performed in sequence:

[0048] (1) Start a stirrer, adjust the speed to 1200 r / min, add special modified polyurethane acrylate, isobornyl methacrylate and epoxy acrylate into the stirrer, and disperse them uniformly;

[0049] (2) Maintaining the rotation speed at 1200 r / min, continue to add dispersant, 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, benzoyl formate, phenyl bis-2,4,6-trimethylbenzoylphosphine oxide, defoamer and leveling agent, and disperse for 5 minutes;

[0050] (3) Adjust the speed to 1500r / min and continue to add color paste until the fineness is ≤25μm and there is no oil shrinkage.

[0051] Example 4

[0052] The UV system battery insulating coating of the present invention is mainly prepared from the following components in the following weight proportions:

[0053]

[0054]

[0055] The color paste is titanium cyan blue.

[0056] The method for preparing the UV system battery insulating coating comprises the following steps performed in sequence:

[0057] (1) Start the mixer and adjust the speed to 1100 r / min. Add special modified polyurethane acrylate, isobornyl methacrylate and epoxy acrylate into the mixer and disperse them evenly.

[0058] (2) Maintaining the rotation speed at 1100 r / min, continue to add dispersant, 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, benzoyl formate, phenyl bis-2,4,6-trimethylbenzoylphosphine oxide, defoamer and leveling agent, and disperse for 8 minutes;

[0059] (3) Adjust the speed to 1300r / min, continue to add color paste, and disperse it until the fineness is ≤25μm and there is no oil shrinkage;

[0060] (4) Adjust the speed to 1100r / min, continue to add white carbon black, and pass it through a 200-mesh sieve after it is evenly dispersed.

[0061] Example 5

[0062] The UV system battery insulating coating of the present invention is mainly prepared from the following components in the following weight proportions:

[0063]

[0064]

[0065] The color paste is titanium cyan blue.

[0066] The method for preparing the UV system battery insulating coating comprises the following steps performed in sequence:

[0067] (1) starting a stirrer, adjusting the speed to 1000 r / min, adding specially modified polyurethane acrylate, isobornyl methacrylate and epoxy acrylate into the stirrer, and dispersing them uniformly;

[0068] (2) Maintaining the rotation speed at 1000 r / min, continue to add dispersant, 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, benzoyl formate, phenyl bis-2,4,6-trimethylbenzoylphosphine oxide, defoamer and leveling agent, and disperse for 10 minutes;

[0069] (3) Adjust the speed to 1200r / min, continue to add color paste, and disperse it until the fineness is ≤25μm and there is no oil shrinkage;

[0070] (4) Adjust the speed to 1000r / min, continue to add white carbon black, and pass it through a 220-mesh sieve after it is evenly dispersed.

[0071] Example 6

[0072] The UV system battery insulating coating of the present invention is mainly prepared from the following components in the following weight proportions:

[0073]

[0074] The color paste is titanium cyan blue.

[0075] The method for preparing the UV system battery insulating coating comprises the following steps performed in sequence:

[0076] (1) Start a stirrer, adjust the speed to 1200 r / min, add special modified polyurethane acrylate, isobornyl methacrylate and epoxy acrylate into the stirrer, and disperse them uniformly;

[0077] (2) Maintaining the rotation speed at 1200 r / min, continue to add dispersant, 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, benzoyl formate, phenyl bis-2,4,6-trimethylbenzoylphosphine oxide, defoamer and leveling agent, and disperse for 5 minutes;

[0078] (3) Adjust the speed to 1500r / min, continue to add color paste, and disperse it until the fineness is ≤25μm and there is no oil shrinkage;

[0079] (4) Adjust the speed to 1200r / min, continue to add white carbon black, and pass it through a 180-mesh sieve after it is evenly dispersed.

[0080] Raw material information involved in each embodiment:

[0081] Special modified polyurethane acrylate: Haohui CR93013

[0082] Isobornyl methacrylate: Haohui IBOMA

[0083] Epoxy acrylate: Allnex EB9636

[0084] Dispersant: BYK 2009

[0085] 2,4,6-Trimethylbenzoyl-diphenylphosphine oxide: Yuchang Chemical KL TPO

[0086] Benzoylformate: Double Bond Chemical MBF

[0087] Phenyl bis(2,4,6-trimethylbenzoylphosphine oxide): JIURI BAPO

[0088] Defoamer: Digo 920

[0089] Leveling agent: BYK333

[0090] White carbon black: Albemarle M5.

[0091] Experimental data:

[0092] Detection method:

[0093] The odor detection method and standard refer to VDA270:1992-10; the paint film toughness detection method and standard refer to GB / T1731-93; the adhesion detection method and standard refer to GB / T 9286 (equivalent translation of ISO2409); the solvent resistance detection method and standard refer to GB / T 9274-1988; the aging resistance detection method and standard refer to GB / T 2423.3-2016; the impact resistance detection method and standard refer to GB / T 23999-2009;

[0094] Sagging: Use a professional tool, sag meter, for testing

[0095] Insulation resistance: Use a professional tool resistance meter to test

[0096] Hardness: Tested using a pencil hardness tester

[0097] Viscosity determination: DIN 53019-1, measured at 25°C using a rotational viscometer.

[0098] The results are shown in Table 1:

[0099] Table 1 Performance test results

[0100]

[0101]

[0102]

[0103] It can be seen that the bonding force, anti-aging, adhesion, insulation withstand voltage, impact resistance and other properties of the products of each embodiment meet the requirements of product development, and have good construction performance, fast curing speed, high production efficiency, low product viscosity, can be constructed by UV inkjet, and the paint film is uniform and thin after spraying, which does not affect the product effect, can reduce costs to a certain extent, and only needs to be cured by a conventional ultraviolet curing machine, and curing can be completed in one pass (only a dozen seconds). Among them, Example 4 is the best case.

Claims

1. A UV system battery insulating coating, characterized in that: It is mainly prepared from the following components in the following weight proportions:

2. The UV system battery insulating coating according to claim 1, characterized in that: The UV system battery insulation coating also includes 0.1-10 parts of white carbon black.

3. The UV system battery insulating coating according to claim 1, characterized in that: The color paste is titanium cyan blue.

4. The method for preparing the UV system battery insulating coating according to any one of claims 1 to 3, characterized in that: The steps are as follows: (1) Start a stirrer, adjust the speed to 1000-1200 r / min, add special modified polyurethane acrylate, isobornyl methacrylate and epoxy acrylate into the stirrer, and disperse them uniformly; (2) Maintaining the rotation speed at 1000-1200 r / min, continue to add dispersant, 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, benzoyl formate, phenyl bis-2,4,6-trimethylbenzoylphosphine oxide, defoamer and leveling agent, and disperse for 5-10 minutes; (3) Adjust the speed to 1200-1500r / min, continue to add color paste, and disperse it until the fineness is ≤25μm and there is no oil shrinkage.

5. The method for preparing the UV system battery insulating coating according to claim 4, characterized in that: The method further comprises step (4): adjusting the rotation speed to 1000-1200 r / min, continuously adding white carbon black, and passing the mixture through a 180-220 mesh sieve after the mixture is evenly dispersed.

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