Button cell contact avoidance tracer coating and method of making and use thereof

Abstract

This invention discloses a contact avoidance tracer coating for button batteries, its preparation method, and its application, belonging to the field of battery coating preparation technology. The contact avoidance tracer coating for button batteries comprises the following components by weight: 35-45 parts water-soluble film-forming resin, 45-55 parts saliva tracer dye, 3-6 parts bittering agent, 2-5 parts adhesion promoter, 0.1-0.5 parts surfactant, and 1-2 parts rheology modifier. The coating prepared using the above substances exhibits excellent adhesion and tracer properties.

Description

Technical Field

[0001] This invention belongs to the field of battery coating preparation technology, specifically relating to a button cell contact avoidance tracer coating, its preparation method, and its application. Background Technology

[0002] Button batteries are widely used in electronic watches, calculators, hearing aids, smart wearable devices, children's toys, and other portable electronic products due to their small size, light weight, stable capacity, and portability. Among them, small batteries such as lithium manganese button batteries, alkaline button batteries, and silver oxide button batteries typically use a metal casing as the external encapsulation structure, and are electrically connected to the internal conductive terminals of the device through the positive and negative terminals. Because of their small size and smooth appearance, button batteries are easily mistaken for candy or pills by children or people with special needs, posing a risk of accidental ingestion. Once inside the body, the battery casing comes into contact with saliva, and under the influence of electrochemical reactions, local current, and tissue fluid, damage to the oral cavity, esophagus, or gastrointestinal tract tissues may occur. Therefore, improving the ability to identify button batteries when they are accidentally ingested and reducing the risk of accidental ingestion has become an important research direction in the field of small battery safety protection.

[0003] In existing technologies, to improve the ability of button batteries to detect accidental ingestion, methods such as setting warning labels, printing text and patterns, adding color markings, or adding bitter substances are commonly used on the surface of the battery casing. However, traditional ink printing layers mainly rely on visual recognition and cannot be effective in dark environments or when children cannot actively identify them. At the same time, the adhesion between ordinary marking layers and metal casings is limited, and they are prone to peeling, wear, or fading during transportation, friction, or long-term storage. In addition, when bitter agents are added alone, the bitter substances are easily blocked by the encapsulation material, making it difficult to make sufficient contact with saliva in a short time, resulting in insufficient stimulation. Some existing coatings use highly cross-linked or non-water-soluble resin systems to improve adhesion performance, but these coatings have the problems of slow release in saliva environments and difficulty in balancing adhesion stability and rapid warning performance.

[0004] Therefore, there is an urgent need to develop a contact-avoidance tracer coating suitable for the surface of button cell battery casings. This coating should possess good adhesion, abrasion resistance, and electrical insulation safety during normal storage and use. Simultaneously, it should rapidly release tracer dyes and bittering agents upon accidental ingestion and contact with saliva, providing both visual and gustatory warnings. Furthermore, the coating should avoid covering the effective electrical contact area of ​​the button cell battery to prevent interference with the conductive connection between the battery and electronic devices, thus meeting the requirements of compatibility between button cell battery safety protection and normal performance. Summary of the Invention

[0005] The purpose of this invention is to provide a contact avoidance tracer coating for button batteries, its preparation method, and its application, in order to solve the technical problems of existing button battery casing warning coatings being easily worn or detached after storage, transportation, and assembly friction, insufficient release rate of tracer dyes and bittering agents when exposed to saliva, and easy increase in contact resistance after the coating covers the effective electrical contact area.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: The present invention provides a button battery contact avoidance tracer coating, which is composed of the following components in parts by weight: 35-45 parts of water-soluble film-forming resin, 45-55 parts of saliva tracer dye, 3-6 parts of bittering agent, 2-5 parts of adhesion promoter, 0.1-0.5 parts of surfactant and 1-2 parts of rheology modifier.

[0007] Preferably, the method for preparing the water-soluble film-forming resin includes the following steps: S1: Add high molecular weight polyvinyl alcohol and low molecular weight polyvinyl alcohol to deionized water, heat and stir to dissolve, cool down, and obtain compound mother liquor; S2: Sodium polyacrylate is added to deionized water and stirred to obtain a carboxyl component solution; phytate is added to deionized water and stirred to obtain a phytate component solution; polymer phosphate is added to an ethanol aqueous solution and stirred to obtain a phosphate component solution; the carboxyl component solution, phytate component solution and phosphate component solution are mixed and stirred, and the pH is adjusted to obtain a modified solution; S3: Add the modified liquid to the compound mother liquor, stir and mature, adjust the pH, add sodium dodecyl sulfate, continue stirring, filter, degas, and let stand to obtain water-soluble film-forming resin.

[0008] Preferably, the ratio of high molecular weight polyvinyl alcohol, low molecular weight polyvinyl alcohol, and deionized water is (4-10) g : (1.8-3.6) g : (90-110) mL, the weight average molecular weight of the high molecular weight polyvinyl alcohol is 50,000-150,000 g / mol, and the degree of hydrolysis is 87-93%; the weight average molecular weight of the low molecular weight polyvinyl alcohol is 5,000-50,000 g / mol, and the degree of hydrolysis is 80-88%; the heating and stirring temperature is 85-95℃, the time is 60-90 min, the stirring speed is 600-1000 rpm, and the temperature is cooled to 30-40℃.

[0009] Preferably, the phytate is selected from one or more of sodium phytate, potassium phytate, and ammonium phytate; the polymer phosphate is selected from one or more of hydroxyl-functionalized polymer phosphate, carboxyl-functionalized polymer phosphate, polyether phosphate, polyester phosphate, and acrylate phosphate; the volume ratio of the carboxyl component solution, phytate component solution, and phosphate ester component solution is (6-12):(0.8-2.4):(2-6), the volume fraction of the ethanol aqueous solution is 20-60 wt%, the concentration of the carboxyl component solution is 5-12 wt%, the concentration of the phytate component solution is 5-10 wt%, and the concentration of the phosphate ester component solution is 10-16 wt%. The mixture is stirred at 20-30°C for 20-40 min, and the pH is adjusted to 6.0-6.8 with 1 mol / L NaOH aqueous solution.

[0010] As a preferred option, the ratio of modified liquid, compound mother liquor and sodium dodecyl sulfate is (15-25) g: (80-95) g: (0.1-0.18) g. The mixture is stirred and matured at 40-50℃ for 1-3 hours, the pH is adjusted to 6.0-6.5, filtered through a 60-80μm filter, defoamed for 20-30 minutes, and allowed to stand for 8-10 hours.

[0011] Preferably, the saliva tracer dye is composed of one or more of Brilliant Blue FCF, Carmine, Tartrazine, and Allura Red; the bittering agent is denatamium benzoate; the adhesion promoter is composed of one or more of phosphorylated polyvinyl alcohol and polyvinylphosphonic acid; the surfactant is composed of one or more of Tween 80, sodium dodecyl sulfate, and alkyl glycosides; and the rheology modifier is composed of one or more of hydroxyethyl cellulose, xanthan gum, nanocellulose, and sodium alginate.

[0012] Preferably, the method for preparing the button cell contact avoidance tracer coating includes the following steps: Step 1: Add the water-soluble film-forming resin to deionized water, stir and disperse to obtain a resin dispersion; Step 2: Add the saliva tracer dye to deionized water, stir to dissolve, filter, and obtain the tracer dye solution; Step 3: Add the bittering agent to deionized water, stir to dissolve, and obtain a bittering agent solution; Step 4: Mix the resin dispersion, tracer dye solution and bittering agent solution, then add adhesion promoter, surfactant and rheology modifier, stir evenly, adjust pH, filter, degas to obtain button battery contact avoidance tracer coating solution; Step 5: Apply the obtained button cell contact avoidance tracer coating liquid to the non-contact functional area of ​​the button cell casing. After drying, the button cell contact avoidance tracer coating is obtained.

[0013] Preferably, in step one, the solid content of the resin dispersion is 10-20 wt%, the stirring speed is 800-1200 rpm, and the time is 40-60 min; in step two, the concentration of the tracer dye solution is 20-35 wt%.

[0014] Preferably, in step three, the concentration of the bittering agent solution is 10-25 wt%; in step four, the total solid content of the obtained button battery contact avoidance tracer coating solution is 20-30 wt%, pH=6.0-6.5, viscosity at 25℃ is 1500-2500 mPa·s, and it is filtered through a 50-80 μm filter membrane with a degassing time of 20-40 min.

[0015] As a preferred option, the application of a contact avoidance tracer coating for coin cells involves applying the coating to the non-contact functional areas on the outer surface of the positive and negative electrode casings of the lithium manganese coin cell.

[0016] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are: 1. This invention employs a blend of high-molecular-weight polyvinyl alcohol (PVA) and low-molecular-weight PVA to form a water-soluble film-forming matrix. High-molecular-weight PVA improves the coating's continuity, mechanical strength, abrasion resistance, and dry integrity, while low-molecular-weight PVA helps improve resin dispersion, reduce system viscosity, and increase the swelling and dissolution rate of the coating upon contact with water or saliva. Further introduction of sodium polyacrylate, phytate, and polymeric phosphate esters allows for hydrogen bonding, ionic association, and multi-point complexation between the PVA hydroxyl groups and carboxylate, phosphate, and phosphate ester groups, forming a functionalized composite film-forming network. This maintains the coating's water solubility and rapid release properties while improving its cohesive strength, flexibility, and adhesion stability to the metal casing of button batteries, reducing cracking, peeling, or powdering during packaging, transportation, and assembly.

[0017] 2. This invention, through the synergistic effect of phytate, polymeric phosphate, and an added adhesion promoter, provides multiple anchoring groups between the coating and the coin cell casing (such as nickel-plated steel or stainless steel) capable of interacting with the oxide layer on the metal surface, thereby enhancing the interfacial adhesion between the coating and the metal substrate. The preparation of the modified solution and its maturation process with the compound mother liquor are carried out under weakly acidic to near-neutral conditions, avoiding the use of strong acids, strong alkalis, and high-temperature curing treatments, thus reducing the risk of corrosion or damage to the coin cell metal casing, sealing gaskets, and sealing structure. Simultaneously, by controlling the concentration and ratio of sodium polyacrylate, phytate, and polymeric phosphate, as well as the system pH, the possibility of resin gelation, precipitation, stratification, and abnormal viscosity increases can be reduced, resulting in a water-soluble film-forming resin with good storage stability and process adaptability.

[0018] 3. This invention incorporates a high concentration of saliva-tracing dye and a bittering agent in the coating. When a button battery is accidentally placed in the mouth and comes into contact with saliva, the water-soluble film-forming resin rapidly absorbs water, swells, dissolves, or disintegrates, causing the tracer dye and bittering agent to be released quickly. The released tracer dye provides a clear color mark on the mouth, tongue, hands, or aqueous media in contact with the battery, facilitating timely identification by monitoring personnel of the risk of the button battery being ingested or swallowed. The released bittering agent produces a strong and persistent aversive taste stimulus, encouraging the user to spit out the battery. The combined effect of the dye tracer and the bittering stimulus creates a more intuitive and timely dual warning effect compared to coatings that only contain a bittering agent or only have color markings, improving the risk identification capability in scenarios where button batteries are accidentally ingested. Detailed Implementation

[0019] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] In this invention, the non-contact functional area refers to the outer surface area of ​​the button cell casing that does not serve as the main contact area for forming an effective electrical connection between the battery and the conductive terminals of the electrical device.

[0021] Example 1: This example discloses a method for preparing a water-soluble film-forming resin, including the following steps: S1: Add 7.0g of high molecular weight polyvinyl alcohol and 2.7g of low molecular weight polyvinyl alcohol to 100mL of deionized water, heat to 90℃, stir at 800rpm for 75min, and cool to 35℃ to obtain the compound mother liquor. The high molecular weight polyvinyl alcohol has a weight-average molecular weight of 90000g / mol and a degree of hydrolysis of 89%; the low molecular weight polyvinyl alcohol has a weight-average molecular weight of 20000g / mol and a degree of hydrolysis of 85%. S2: Sodium polyacrylate was added to deionized water and stirred to obtain a carboxyl component solution with a concentration of 8 wt%; sodium phytate was added to deionized water and stirred to obtain a phytate component solution with a concentration of 6 wt%; hydroxyl-functionalized polymer phosphate ester was added to a 40 vt% ethanol aqueous solution and stirred to obtain a phosphate ester component solution with a concentration of 12 wt%; 8 mL of carboxyl component solution, 1.6 mL of phytate component solution and 4 mL of phosphate ester component solution were mixed and stirred at 25℃ and 600 rpm for 30 min, and the pH was adjusted to 6.3 with 1 mol / L NaOH aqueous solution to obtain the modified solution; S3: Add 20g of modified liquid to 88g of compound mother liquor, stir and mature at 45℃ for 2h, adjust pH=6.3, add 0.14g of sodium dodecyl sulfate, continue stirring for 20min, filter through a 70μm filter, degas for 25min, and let stand for 10h to obtain water-soluble film-forming resin.

[0022] This embodiment discloses a button battery contact avoidance tracer coating, which is composed of the following components by weight: 40 parts water-soluble film-forming resin, 50 parts brilliant blue FCF, 5 parts denatum benzoate, 3.5 parts phosphorylated polyvinyl alcohol, 0.3 parts Tween 80 and 1.2 parts hydroxyethyl cellulose.

[0023] This embodiment discloses a method for preparing a contact avoidance tracer coating for a button cell battery, including the following steps: Step 1: Add water-soluble film-forming resin to deionized water, stir and disperse at 1200 rpm for 60 min to obtain a resin dispersion with a solid content of 20 wt%. Step 2: Add Brilliant Blue FCF to deionized water, stir to dissolve, filter, and obtain a tracer dye solution with a concentration of 35 wt%. Step 3: Add denamonium benzoate to deionized water, stir to dissolve, and obtain a bittering agent solution with a concentration of 25wt%; Step 4: Mix the resin dispersion, tracer dye solution, and bittering agent solution, then add phosphorylated polyvinyl alcohol, Tween 80, and hydroxyethyl cellulose. After stirring evenly, adjust the pH to 6.3, filter through a 60μm filter membrane, and degas for 40 minutes to obtain a button battery contact avoidance tracer coating solution with a total solid content of 25wt% (viscosity of 1500-2500mPa·s at 25℃). Step 5: Apply the obtained button cell contact avoidance tracer coating liquid to the non-contact functional area of ​​the button cell casing. After drying, the button cell contact avoidance tracer coating is obtained.

[0024] Example 2: This example discloses a method for preparing a water-soluble film-forming resin, including the following steps: S1: Add 6.0g of high molecular weight polyvinyl alcohol and 2.2g of low molecular weight polyvinyl alcohol to 95mL of deionized water, heat to 88℃, stir at 700rpm for 70min, and cool to 35℃ to obtain the compound mother liquor. The high molecular weight polyvinyl alcohol has a weight-average molecular weight of 70000g / mol and a degree of hydrolysis of 88%; the low molecular weight polyvinyl alcohol has a weight-average molecular weight of 12000g / mol and a degree of hydrolysis of 82%. S2: Sodium polyacrylate was added to deionized water and stirred to obtain a 5 wt% carboxyl component solution; sodium phytate was added to deionized water and stirred to obtain a 5 wt% phytate component solution; hydroxyl-functionalized polymer phosphate ester was added to a 20 wt% ethanol aqueous solution and stirred to obtain a 10 wt% phosphate ester component solution; 6 mL of carboxyl component solution, 0.8 mL of phytate component solution and 2 mL of phosphate ester component solution were mixed and stirred at 20℃ and 500 rpm for 20 min, and the pH was adjusted to 6.0 with 1 mol / L NaOH aqueous solution to obtain the modified solution; S3: Add 15g of modified liquid to 95g of compound mother liquor, stir and mature at 40℃ for 1h, adjust pH=6.0, add 0.10g of sodium dodecyl sulfate, continue stirring for 15min, filter through a 60μm filter, degas for 20min, and let stand for 8h to obtain water-soluble film-forming resin.

[0025] This embodiment discloses a button battery contact avoidance tracer coating, which is composed of the following components by weight: 42 parts water-soluble film-forming resin, 50 parts lemon yellow, 4.5 parts denatum benzoate, 3.5 parts polyvinylphosphonic acid, 0.4 parts alkyl glycoside and 1.6 parts xanthan gum.

[0026] This embodiment discloses a method for preparing a contact avoidance tracer coating for a button cell battery, including the following steps: Step 1: Add water-soluble film-forming resin to deionized water, stir and disperse at 1200 rpm for 60 min to obtain a resin dispersion with a solid content of 20 wt%. Step 2: Add lemon yellow to deionized water, stir to dissolve, filter, and obtain a tracer dye solution with a concentration of 35wt%; Step 3: Add denamonium benzoate to deionized water, stir to dissolve, and obtain a bittering agent solution with a concentration of 25wt%; Step 4: Mix the resin dispersion, tracer dye solution, and bittering agent solution, then add polyvinylphosphonic acid, alkyl glycoside, and xanthan gum. After stirring evenly, adjust the pH to 6.1, filter through a 50μm filter membrane, and degas for 25 minutes to obtain a button battery contact avoidance tracer coating solution with a total solid content of 25wt% (viscosity of 1500-2500 mPa·s at 25℃). Step 5: Apply the obtained button cell contact avoidance tracer coating liquid to the non-contact functional area of ​​the button cell casing. After drying, the button cell contact avoidance tracer coating is obtained.

[0027] Example 3: This example discloses a method for preparing a water-soluble film-forming resin, including the following steps: S1: Add 8.5g of high molecular weight polyvinyl alcohol and 3.2g of low molecular weight polyvinyl alcohol to 105mL of deionized water, heat to 93℃, stir at 900rpm for 85min, and cool to 40℃ to obtain the compound mother liquor. The high molecular weight polyvinyl alcohol has a weight-average molecular weight of 120,000g / mol and a degree of hydrolysis of 92%; the low molecular weight polyvinyl alcohol has a weight-average molecular weight of 40,000g / mol and a degree of hydrolysis of 88%. S2: Sodium polyacrylate was added to deionized water and stirred to obtain a 12 wt% carboxyl component solution; sodium phytate was added to deionized water and stirred to obtain a 10 wt% phytate component solution; hydroxyl-functionalized polymer phosphate ester was added to a 60 wt% ethanol aqueous solution and stirred to obtain a 16 wt% phosphate ester component solution; 12 mL of carboxyl component solution, 2.4 mL of phytate component solution and 6 mL of phosphate ester component solution were mixed and stirred at 30℃ and 700 rpm for 40 min, and the pH was adjusted to 6.8 with 1 mol / L NaOH aqueous solution to obtain the modified solution; S3: Add 25g of modified liquid to 80g of compound mother liquor, stir and mature at 50℃ for 3h, adjust pH=6.5, add 0.18g of sodium dodecyl sulfate, continue stirring for 30min, filter through an 80μm filter, degas for 30min, and let stand for 10h to obtain water-soluble film-forming resin.

[0028] This embodiment discloses a button battery contact avoidance tracer coating, which is composed of the following components by weight: 38 parts water-soluble film-forming resin, 52 parts Allura Red, 5.5 parts denatamium benzoate, 2 parts polyvinylphosphonic acid, 0.3 parts sodium dodecyl sulfate and 1.2 parts nanocellulose.

[0029] This embodiment discloses a method for preparing a contact avoidance tracer coating for a button cell battery, including the following steps: Step 1: Add water-soluble film-forming resin to deionized water, stir and disperse at 1200 rpm for 60 min to obtain a resin dispersion with a solid content of 20 wt%. Step 2: Add Allura Red to deionized water, stir to dissolve, filter, and obtain a tracer dye solution with a concentration of 35 wt%. Step 3: Add denamonium benzoate to deionized water, stir to dissolve, and obtain a bittering agent solution with a concentration of 25wt%; Step 4: Mix the resin dispersion, tracer dye solution, and bittering agent solution, then add polyvinylphosphonic acid, sodium dodecyl sulfate, and nanocellulose. After stirring evenly, adjust the pH to 6.3, filter through a 60μm filter membrane, and degas for 40 minutes to obtain a button battery contact avoidance tracer coating solution with a total solid content of 25wt% (viscosity of 1500-2500mPa·s at 25℃). Step 5: Apply the obtained button cell contact avoidance tracer coating liquid to the non-contact functional area of ​​the button cell casing. After drying, the button cell contact avoidance tracer coating is obtained.

[0030] Example 4: This example discloses a method for preparing a water-soluble film-forming resin, including the following steps: S1: Add 10.0g of high molecular weight polyvinyl alcohol and 3.6g of low molecular weight polyvinyl alcohol to 110mL of deionized water, heat to 95℃, stir at 1000rpm for 90min, and cool to 35℃ to obtain the compound mother liquor. The high molecular weight polyvinyl alcohol has a weight-average molecular weight of 150,000g / mol and a degree of hydrolysis of 93%; the low molecular weight polyvinyl alcohol has a weight-average molecular weight of 50,000g / mol and a degree of hydrolysis of 88%. S2: Sodium polyacrylate was added to deionized water and stirred to obtain a 10 wt% carboxyl component solution; sodium phytate was added to deionized water and stirred to obtain an 8 wt% phytate component solution; hydroxyl-functionalized polymer phosphate ester was added to a 50 wt% ethanol aqueous solution and stirred to obtain a 14 wt% phosphate ester component solution; 10 mL of carboxyl component solution, 2 mL of phytate component solution and 5 mL of phosphate ester component solution were mixed and stirred at 28℃ and 650 rpm for 35 min, and the pH was adjusted to 6.4 with 1 mol / L NaOH aqueous solution to obtain the modified solution; S3: Add 22g of modified liquid to 85g of compound mother liquor, stir and mature at 48℃ for 2.5h, adjust pH=6.4, add 0.16g of sodium dodecyl sulfate, continue stirring for 25min, filter through an 80μm filter, degas for 30min, and let stand for 10h to obtain water-soluble film-forming resin.

[0031] This embodiment discloses a button battery contact avoidance tracer coating, which is composed of the following components by weight: 40 parts water-soluble film-forming resin, 45 parts carmine red, 4 parts denamonium benzoate, 4.5 parts polyvinylphosphonic acid, 0.3 parts Tween 80 and 1 part sodium alginate.

[0032] This embodiment discloses a method for preparing a contact avoidance tracer coating for a button cell battery, including the following steps: Step 1: Add water-soluble film-forming resin to deionized water, stir and disperse at 1200 rpm for 60 min to obtain a resin dispersion with a solid content of 20 wt%. Step 2: Add carmine to deionized water, stir to dissolve, filter, and obtain a tracer dye solution with a concentration of 35wt%. Step 3: Add denamonium benzoate to deionized water, stir to dissolve, and obtain a bittering agent solution with a concentration of 25wt%; Step 4: Mix the resin dispersion, tracer dye solution, and bittering agent solution, then add polyvinylphosphonic acid, Tween 80, and sodium alginate. After stirring evenly, adjust the pH to 6.2, filter through a 60μm filter membrane, and degas for 40 minutes to obtain a button battery contact avoidance tracer coating solution with a total solid content of 25wt% (viscosity of 1500-2500mPa·s at 25℃). Step 5: Apply the obtained button cell contact avoidance tracer coating liquid to the non-contact functional area of ​​the button cell casing. After drying, the button cell contact avoidance tracer coating is obtained.

[0033] Comparative Example 1: Compared with Example 1, in the process of preparing the button battery contact avoidance tracer coating liquid, Comparative Example 1 did not add low molecular weight polyvinyl alcohol in the water-soluble film-forming resin preparation step S1, but adjusted the amount of high molecular weight polyvinyl alcohol added from 7.0g to 9.7g, while other conditions remained unchanged.

[0034] Comparative Example 2: Compared with Example 1, in the process of preparing the button battery contact avoidance tracer coating liquid, Comparative Example 2 did not add high molecular weight polyvinyl alcohol in the water-soluble film-forming resin preparation step S1, but adjusted the amount of low molecular weight polyvinyl alcohol added from 2.7g to 9.7g, while other conditions remained unchanged.

[0035] Comparative Example 3: Compared with Example 1, in the process of preparing the button cell contact avoidance tracer coating liquid, Comparative Example 3 did not prepare and add sodium polyacrylate carboxyl component solution in step S2, and all other conditions remained unchanged.

[0036] Comparative Example 4: Compared with Example 1, in the preparation of the button cell contact avoidance tracer coating liquid, sodium phytate solution was not prepared and added in step S2, and other conditions remained unchanged.

[0037] Comparative Example 5: Compared with Example 1, Comparative Example 5 did not add hydroxyl-functionalized polymer phosphate ester in step S2 during the preparation of the button battery contact avoidance tracer coating liquid, and all other conditions remained unchanged.

[0038] Comparative Example 6: Compared with Example 1, Comparative Example 6 did not add 5 parts of denamonium benzoate during the preparation of the button battery contact avoidance tracer coating liquid, and all other conditions remained unchanged.

[0039] Comparative Example 7: Compared with Example 1, Comparative Example 7 did not add 50 parts of brilliant blue FCF during the preparation of the button cell contact avoidance tracer coating liquid, and all other conditions remained unchanged.

[0040] Performance testing: The coatings prepared in Examples 1-4 and Comparative Examples 1-7 were subjected to performance tests. Samples were taken according to GB / T 3186-2006; the non-volatile matter content (i.e., solid content) was tested according to GB / T 1725-2007; the viscosity at 25°C was tested according to GB / T 2794-2022; the pH value was tested according to GB / T 9724-2007; and the storage stability was tested according to GB / T 6753.3-1986. After the coating liquid was applied to the non-contact functional areas of the button cell casing and dried to form a film, the coating thickness was tested according to GB / T 13452.2-2008; the coating drying time was tested according to GB / T 1728-2020; and the performance was tested according to GB / T 9286-2021 and GB / T GB / T 5210-2006 tests the cross-cut adhesion and pull-off adhesion of the coating, GB / T 1768-2006 tests the abrasion resistance of the coating, GB / T 1731-2020 and GB / T 1732-2020 tests the flexibility and impact resistance of the coating, and GB / T 6739-2022 tests the pencil hardness of the coating. Referring to the test conditions of GB / T 1733-1993, GB / T 9274-1988 and GB / T 18886-2019, the coating samples are placed in deionized water or artificial saliva to test their water absorption, swelling, disintegration, dissolution and release properties. The release amount of tracer dye is determined by UV-Vis spectrophotometry according to GB / T 9721-2006, and the release amount of denatum benzoate is determined by high performance liquid chromatography. Sensory evaluation of bitterness release effect was conducted according to GB / T 10220-2012, GB / T 12310-2012, GB / T 12312-2012 and GB / T 22366-2022. Low temperature, high temperature, constant damp heat and temperature cycling reliability tests were performed on the samples according to GB / T 2423.1-2008, GB / T 2423.2-2008, GB / T 2423.3-2016 and GB / T 2423.22-2012. Corrosion resistance of the coating and metal substrate was evaluated according to GB / T 10125-2021 and GB / T 6461-2002. The test results are shown in Tables 1-6. Table 1 Test results of coating solution process performance Table 2 Test results of film-forming properties of the coating base Table 3. Test results of coating adhesion and abrasion resistance Table 4. Test results of coating saliva-triggered release and tracer performance Table 5. Battery compatibility, corrosion resistance, and overall evaluation results. As shown in Tables 1 to 5, the solid content of the button battery contact avoidance tracer coating solutions obtained in Examples 1-4 remained stable within the range of 24.8%-25.3%, the viscosity at 25℃ was 1650-2380 mPa·s, and the pH was 6.1-6.3. Furthermore, no significant stratification, sedimentation, or gelation was observed after 7 days of storage at 45℃, indicating that the coating solution of this invention has good application adaptability and storage stability. The coatings obtained in Examples 1-4 exhibited uniform thickness, moderate surface drying and hard drying times, cross-cut adhesion reaching grade 0-1, and pull-out adhesion of 2.52-3.12 MPa. They also showed low abrasion resistance loss and no significant cracking or peeling after damp heat and temperature cycling. This indicates that the composite film-forming network formed between high molecular weight polyvinyl alcohol, low molecular weight polyvinyl alcohol, carboxyl components, phytic acid components, and phosphate ester components can effectively improve the continuity, cohesive strength, flexibility, abrasion resistance, and adhesion stability to the metal casing of the coating.

[0041] Comparative Example 1, without the addition of low molecular weight polyvinyl alcohol, showed an increased system viscosity of 3560 mPa·s, an extended T90 for artificial saliva to 180 s, and significantly reduced dye release rate at 30 s and bittering agent release rate at 60 s. This indicates that low molecular weight polyvinyl alcohol helps reduce system viscosity and promotes rapid swelling and release of the coating upon contact with saliva. Comparative Example 2, without the addition of high molecular weight polyvinyl alcohol, showed a faster release rate, but significantly worse cross-cut adhesion, pull-out adhesion, abrasion resistance, and appearance after temperature cycling. This indicates that high molecular weight polyvinyl alcohol plays a crucial role in the mechanical strength and dry integrity of the coating. Comparative Example 3, without the addition of sodium polyacrylate, showed a decreased release rate and poorer storage stability, indicating that carboxyl components help improve water absorption and swelling, as well as system stability. Comparative Examples 4 and 5, lacking sodium phytate and hydroxyl-functionalized polymer phosphate ester, respectively, showed decreased adhesion and increased abrasion loss after humid heat. This indicates that phytate groups and phosphate ester groups can form effective interfacial bonds with the metal surface, thereby enhancing coating adhesion. Comparative Example 6, without the addition of a bittering agent, exhibited colorimetric tracing properties, but the release of the bittering agent was undetectable. Comparative Example 7, without the addition of a tracer dye, still exhibited a bittering release effect, but the tracer color difference ΔE was only 1.8, essentially failing to create a visual warning. This demonstrates that the present invention, through the synergistic combination of film-forming resin, tracer dye, bittering agent, and adhesion-promoting components, enables the coating to simultaneously possess excellent coating processability, metal adhesion stability, handling resistance, rapid release upon contact with saliva, color tracing, and bittering warning properties. Furthermore, it has minimal impact on the contact resistance, voltage retention rate, and corrosion resistance of button cells, thus meeting the requirements for functionalized warning coatings in the non-contact areas of button cells.

[0042] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

[0043] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to specific implementations. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A button cell battery contact avoidance tracer coating, characterized in that, It is composed of the following components by weight: 35-45 parts water-soluble film-forming resin, 45-55 parts saliva tracer dye, 3-6 parts bittering agent, 2-5 parts adhesion promoter, 0.1-0.5 parts surfactant and 1-2 parts rheology modifier; the water-soluble film-forming resin is prepared from polyvinyl alcohol, sodium polyacrylate, phytate, polymer phosphate ester and sodium dodecyl sulfate.

2. The button battery contact avoidance tracer coating according to claim 1, characterized in that, The method for preparing the water-soluble film-forming resin includes the following steps: S1: Add high molecular weight polyvinyl alcohol and low molecular weight polyvinyl alcohol to deionized water, heat and stir to dissolve, cool down, and obtain compound mother liquor; S2: Sodium polyacrylate is added to deionized water and stirred to obtain a carboxyl component solution; phytate is added to deionized water and stirred to obtain a phytate component solution; polymer phosphate is added to an ethanol aqueous solution and stirred to obtain a phosphate component solution; the carboxyl component solution, phytate component solution and phosphate component solution are mixed and stirred, and the pH is adjusted to obtain a modified solution; S3: Add the modified liquid to the compound mother liquor, stir and mature, adjust the pH, add sodium dodecyl sulfate, continue stirring, filter, degas, and let stand to obtain water-soluble film-forming resin.

3. The button battery contact avoidance tracer coating according to claim 2, characterized in that, In step S1, the ratio of high molecular weight polyvinyl alcohol, low molecular weight polyvinyl alcohol, and deionized water is (4-10) g : (1.8-3.6) g : (90-110) mL. The weight-average molecular weight of the high molecular weight polyvinyl alcohol is 50,000-150,000 g / mol, and the degree of hydrolysis is 87-93%. The weight-average molecular weight of the low molecular weight polyvinyl alcohol is 5,000-50,000 g / mol, and the degree of hydrolysis is 80-88%. The heating and stirring temperature is 85-95℃, the time is 60-90 min, the stirring speed is 600-1000 rpm, and the temperature is lowered to 30-40℃.

4. The button battery contact avoidance tracer coating according to claim 2, characterized in that, In S2, the phytate is selected from one or more of sodium phytate, potassium phytate, and ammonium phytate; the polymer phosphate is selected from one or more of hydroxyl-functionalized polymer phosphate, carboxyl-functionalized polymer phosphate, polyether phosphate, polyester phosphate, and acrylate phosphate; the volume ratio of the carboxyl component solution, the phytate component solution, and the phosphate component solution is (6-12):(0.8-2.4):(2-6).

5. The button battery contact avoidance tracer coating according to claim 2, characterized in that, In S3, the ratio of the amount of modified liquid, compound mother liquor and sodium dodecyl sulfate is (15-25) g: (80-95) g: (0.1-0.18) g.

6. The button battery contact avoidance tracer coating according to claim 1, characterized in that, The saliva tracer dye is composed of one or more of Brilliant Blue FCF, Carmine, Tartrazine, and Allura Red; the bittering agent is denatamium benzoate; the adhesion promoter is composed of one or more of phosphorylated polyvinyl alcohol and polyvinylphosphonic acid; the surfactant is composed of one or more of Tween 80, sodium dodecyl sulfate, and alkyl glycosides; and the rheology modifier is composed of one or more of hydroxyethyl cellulose, xanthan gum, nanocellulose, and sodium alginate.

7. The method for preparing the button cell contact avoidance tracer coating as described in any one of claims 1-6, characterized in that, Includes the following steps: Step 1: Add the water-soluble film-forming resin to deionized water, stir and disperse to obtain a resin dispersion; Step 2: Add the saliva tracer dye to deionized water, stir to dissolve, filter, and obtain the tracer dye solution; Step 3: Add the bittering agent to deionized water, stir to dissolve, and obtain a bittering agent solution; Step 4: Mix the resin dispersion, tracer dye solution and bittering agent solution, then add adhesion promoter, surfactant and rheology modifier, stir evenly, adjust pH, filter, degas to obtain button battery contact avoidance tracer coating solution; Step 5: Apply the obtained button cell contact avoidance tracer coating liquid to the non-contact functional area of ​​the button cell casing. After drying, the button cell contact avoidance tracer coating is obtained.

8. The method for preparing the button cell contact avoidance tracer coating according to claim 7, characterized in that, In step one, the solid content of the resin dispersion is 10-20 wt%, the stirring speed is 800-1200 rpm, and the time is 40-60 min; in step two, the concentration of the tracer dye solution is 20-35 wt%.

9. The method for preparing the button cell contact avoidance tracer coating according to claim 7, characterized in that, In step three, the concentration of the bittering agent solution is 10-25 wt%; in step four, the total solid content of the obtained button battery contact avoidance tracer coating solution is 20-30 wt%, pH=6.0-6.5, viscosity at 25℃ is 1500-2500 mPa·s, and it is filtered through a 50-80 μm filter membrane with a degassing time of 20-40 min.

10. The application of a button cell contact avoidance tracer coating, characterized in that, The coating is applied to the non-contact functional areas on the outer surface of the positive and negative electrode casings of lithium manganese button cells.

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