A method for preparing a water-based matte coating for a battery label

Abstract

The application discloses a preparation method of a water-based matte coating for a battery label, and comprises the following preparation steps: (1) preparing a reactive high-molecular surfactant crosslinking agent; (2) preparing a monomer pre-emulsion; (3) preparing a water-based acrylic ester pressure-sensitive adhesive; (4) preparing a high-strength high-molecular weight resin; and (5) preparing a water-based matte coating. The prepared reactive high-molecular surfactant crosslinking agent has good monomer emulsifying performance, guarantees the bonding strength and water resistance of the pressure-sensitive adhesive; acryloyl morpholine greatly reduces the influence of the emulsifier on the performance of the pressure-sensitive adhesive; the resin synthesized through the bulk polymerization method has a large molecular weight, the isooctyl ester increases the non-polarity of the resin, and the adhesive increases the wettability of the adhesive and the label; the tetrafunctional epoxy resin curing agent has high reactivity with the acrylic ester coating, and after crosslinking, the cohesive strength, weather resistance and aging resistance of the coating are significantly improved; the acrylic ester coating crosslinked and cured by the tetrafunctional epoxy resin curing agent basically does not decrease the adhesion after being aged for 96 hours at 70 DEG C.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of preparing frosted coatings, and particularly relates to a preparation method of a water-based frosted coating for a battery label. BACKGROUND

[0002] With the development of the printing industry and the increase of people's innovation consciousness, the advantages of adopting the frosted process for printed matter are that the printed matter can achieve solemn, elegant aesthetics and good hand feeling, and the printed matter adopting the frosted process obviously feels different from the effect of printing by other processes. The main difference can be analyzed from the naked eye sense and hand feeling of the printed matter: 1. Since the surface of the printed matter has undergone the frosted process, the surface becomes rougher, at this time the surface gloss of the printed matter will be significantly reduced, and the surface of the printed matter after frosted will increase the darkness. Frosted can also become a beautiful pattern, which is easily realized through the printing process. 2. The printed matter after adopting the printing process frosted has a slight stinging feeling, the surface roughness of the printed matter increases, and the friction force will also increase when holding such an outer packaging printed matter, which can reduce the risk brought by the falling of such packaging products. In addition, the printed matter adopting the frosted process is not easy to be stained with fingerprints and traces, which is of great significance for keeping the product outer packaging "new", especially for the packaging of samples placed in the store.

[0003] At present, the main frosted process on the market is UV frosted. Since the UV adhesive does not contain a low-cost solvent in its composition, the manufacturing cost of the UV adhesive is higher than that of ordinary adhesives, and the corresponding sales price is also high. The UV adhesive must have a ultraviolet light source to be cured, and the bonding material needs to have one side of light transmission to allow the ultraviolet light source to shine in, and the high-temperature resistance is poor.

[0004] CN114621695A discloses a blue-light-resistant antibacterial frosted coating, a coating layer and a protective film and a preparation method using the same. The disadvantages of this frosted coating are as follows: the frosted coating is a UV adhesive, since the UV adhesive does not contain a low-cost solvent in its composition, the manufacturing cost of the UV adhesive is higher than that of ordinary adhesives, and the corresponding sales price is also high. The UV adhesive must have a ultraviolet light source to be cured, and the bonding material needs to have one side of light transmission to allow the ultraviolet light source to shine in, and the high-temperature resistance is poor.

[0005] CN111116954A discloses a preparation method of a film with a high-transmittance frosted coating. The disadvantages of this frosted coating are as follows: the frosted coating is solvent-based. From the analysis of the use environment, the volatile organic solvent of the solvent-based adhesive has certain harm to the human body and causes certain pollution to the environment, which does not meet the basic requirements and trends of environmental protection, health and safety. From the cost analysis, the cost of the solvent-based adhesive is much higher than that of the water-based adhesive. SUMMARY

[0006] In view of the deficiencies in the background art, the application researches and designs a preparation method of a water-based sanding coating for battery labels, which aims to provide a preparation method of a water-based sanding coating for battery labels, which has good adhesion, strong sanding effect, and significantly improved weather resistance and aging resistance.

[0007] The technical solution of the application:

[0008] A preparation method of a water-based sanding coating for battery labels, comprising the following preparation steps:

[0009] (1) Preparation of reactive polymer surfactant crosslinking agent

[0010] Put butanone into the reactor, when the temperature rises to 60℃, add glyceryl oleate, acryloyl morpholine, catalyst, polymerization inhibitor into the reactor in turn, vacuum to 0.09MPa, heat to 130-140℃, keep the temperature for 10-15h, cool to 80℃, add deionized water, allyloxy hydroxypropyl sulfonic acid sodium, catalyst, react for 1-3h, add triethylamine to adjust the pH value to 7, cool to 50-60℃, vacuum for 1-5h, extract butanone, and get amphiphilic block oligomer, namely reactive polymer surfactant crosslinking agent;

[0011] (2) Preparation of monomer pre-emulsion

[0012] Mix the reactive polymer surfactant crosslinking agent in step (1), part of deionized water, acrylate monomer, crosslinking monomer, chain transfer agent and oxidizing agent, and then emulsify by high-speed stirring to get monomer pre-emulsion;

[0013] (3) Preparation of water-based acrylate pressure-sensitive adhesive

[0014] Heat the remaining deionized water to 80-85℃, add part of the monomer pre-emulsion prepared in step (2), add oxidizing agent, react for 20min, drop the remaining monomer pre-emulsion within 3-5h, keep the temperature at 80℃ for 1h, cool to 60-65℃, drop the reducing agent, after the reducing agent is dropped, keep the temperature at 60-65℃ for half an hour, then heat to 80℃ for 1h, then cool to below 45℃, add pH regulator to adjust the pH value of the emulsion to 7-8, stir uniformly, filter the material, and get water-based acrylate pressure-sensitive adhesive;

[0015] (4) Preparation of high-strength high-molecular-weight resin

[0016] The acrylic acid, styrene, isooctyl ester, methyl isobutyl ester, initiator are mixed, part of the mixed monomers are added into the reactor, nitrogen protection is carried out by nitrogen, the temperature is controlled at 60℃, and reaction is carried out for 1h; the remaining mixed monomers are titrated into the reactor, the titration time is 3h, the titration temperature is controlled at 60-65℃, and after the titration is completed, 60-65℃ is kept for 1h, thereby high-strength high-molecular-weight resin is obtained.

[0017] (5) Preparation of water-based sanding coating

[0018] The high-strength high-molecular-weight resin prepared in step (4) is added into the water-based acrylic ester pressure-sensitive adhesive prepared in step (3), high-speed dispersion is carried out by a dispersion disc, a dispersing agent and a filler are added, high-speed dispersion is carried out for 30 min, then a curing agent is added, and stirring is continued for 5 min, thereby the water-based sanding coating is obtained.

[0019] The mass ratio of the sodium allyloxy hydroxypropyl sulfonate, the acryloyl morpholine, the butanone, the glyceryl oleate and the catalyst in step (1) is 5-10:3-5:60-150:8-12:0.4-1.2.

[0020] The catalyst in step (1) is p-toluenesulfonic acid.

[0021] The mass ratio of the high-molecular surfactant crosslinking agent, the part of deionized water, the acrylic ester monomer, the crosslinking monomer, the chain transfer agent and the oxidant in step (2) is 1-10:100-150:200-300:10-20:0.03-0.2:0.5-1.

[0022] The acrylic ester monomer in step (2) is butyl acrylate, methyl methacrylate, glycidyl methacrylate or allyl methacrylate.

[0023] The crosslinking monomer in step (2) is hydroxyethyl acrylate.

[0024] The chain transfer agent in step (2) is isooctyl 3-mercapto propionate.

[0025] The oxidant in step (2) is potassium persulfate.

[0026] The PH regulator in step (3) is triethylamine.

[0027] The reducing agent in step (3) is disodium hydroxyethanesulfinate.

[0028] The oxidant in step (3) is potassium persulfate.

[0029] The mass ratio of the oxidant, the deionized water and the monomer pre-emulsion in step (3) is 0.5-1:100-150:30-50.

[0030] The mass ratio of acrylic acid, styrene, isooctyl ester, methyl isobutyl ester, initiator in the step (4) is 20-30:15-30:100-200:15-30:0.05-0.2.

[0031] The initiator in the step (4) is azobisdimethyl isobutyl.

[0032] The dispersing agent in the step (5) is nano-sized silicon dioxide.

[0033] The filler in the step (5) is quartz sand.

[0034] The curing agent in the step (5) is a tetra-functional epoxy resin curing agent.

[0035] The beneficial effects of the present application are: 1. The reactive macromolecular surfactant crosslinking agent is synthesized by using active radical polymerization, and the water-resistant and weather-resistant water-based acrylate pressure-sensitive adhesive is prepared by emulsifying monomers for soap-free emulsion polymerization. The reactive macromolecular surfactant crosslinking agent synthesized in the present application has good monomer emulsifying performance, can be used alone to emulsify monomers, and is a macromolecular polymer with large molecular weight, which is not easy to migrate to the surface of the film after aging, ensuring the bonding strength and water resistance of the pressure-sensitive adhesive, and the reactant acryloyl morpholine contains a double bond with reactivity, which greatly reduces the influence of the emulsifier on the performance of the pressure-sensitive adhesive; 2. The high-strength and high-molecular-weight resin used in the present application is self-made, and the resin synthesized by bulk polymerization has large molecular weight, and the soft monomer used in the reaction is isooctyl ester, which increases the non-polarity of the resin and thus increases the wettability of the glue and the label. Methyl isobutyl ester can improve the strength of the pressure-sensitive adhesive, i.e. the wear resistance. Without adding resin, the wear resistance of the water-based sanding coating is tested by using a rubbing tester, and the scratch line is clear and visible. In the presence of resin, the wear resistance of the water-based sanding coating is tested by using a rubbing tester, and the scratch line is almost invisible or completely invisible; 3. The curing agent used in the present application is a tetra-functional epoxy resin curing agent, which has high reactivity with the acrylate coating, and the cohesive strength, weather resistance, and aging resistance of the coating after crosslinking are significantly improved. The acrylate coating crosslinked and cured by the curing agent has basically no adhesion loss after aging at 70℃ for 96h. DETAILED DESCRIPTION

[0036] The present application is further described below in conjunction with specific examples.

[0037] Example 1

[0038] (1) Put 90 g butanone into a reactor, when the temperature rises to 60℃, add 10 g glyceryl oleate, 3 g acryloyl morpholine, 0.5 g p-toluene sulfonic acid into the reactor in turn, vacuumize to 0.09 MPa, raise the temperature to 130-140℃, keep the temperature for 15 h, cool to 80℃, add 40 g deionized water, 8 g allyloxy hydroxypropyl sulfonic acid sodium, catalyst p-toluene sulfonic acid, react for 3 h, add 1 g triethylamine to adjust the pH value to 7, cool to 50-60℃, vacuumize for 1-5 h, extract butanone to obtain an amphiphilic block oligomer, i.e. a reactive macromolecular surface active crosslinking agent;

[0039] (2) Mix 5 g reactive macromolecular surface active crosslinking agent, 140 g deionized water, 180 g butyl acrylate, 60 g methyl methacrylate, 10 g glycidyl methacrylate, 20 g allyl methacrylate, 15 g hydroxyethyl acrylate, 0.09 g 3-mercapto propionic acid isooctyl ester, 0.75 g potassium persulfate, and then emulsify to obtain a monomer pre-emulsion under high speed stirring;

[0040] (3) Heat 140 g deionized water to 80℃, add 30 g monomer pre-emulsion prepared in step (2), add 0.75 g potassium persulfate, react for 20 min, drop the remaining monomer pre-emulsion in 4 h, keep the temperature at 80℃ for 1 h, cool to 60-65℃, drop 0.5 g disodium hydroxyacetate sulfinate, after the dropping is completed, keep the temperature at 60-65℃ for 30 min, then raise the temperature to 80℃ and keep for 1 h, then cool to below 45℃, add 5 g potassium hydroxide to adjust the emulsion pH value to 7-8, stir uniformly, filter the product to obtain a water-based acrylate pressure-sensitive adhesive;

[0041] (4) Mix 20 g acrylic acid, 25 g styrene, 150 g isooctyl ester, 20 g methyl isobornyl ester, 0.16 g azobis isobutyl, add 1 / 3 of the mixture into a reactor, protect under nitrogen, control the temperature at 60℃, react for 1 h, drop the remaining 2 / 3 of the mixture, the dropping time is 3 h, the dropping temperature is controlled at 60-65℃, after the dropping is completed, keep the temperature at 60-65℃ for 1 h, to obtain a high-strength high-molecular-weight resin;

[0042] (5) Add 60 g high-strength high-molecular-weight resin into 600 g water-based acrylate pressure-sensitive adhesive, disperse under high speed by a dispersing disc, add 10 g nano-sized silicon dioxide and 20 g quartz sand, disperse for 30 min under high speed, then add 0.3 g tetrafunctional epoxy resin curing agent, continue to stir for 5 min, to obtain a water-based sanding coating.

[0043] Example 2

[0044] (1) Put 120 g butanone into a reactor, when the temperature rises to 60℃, add 8 g glyceryl oleate, 4 g acryloyl morpholine, 0.5 g p-toluene sulfonic acid into the reactor in turn, vacuumize to 0.09 MPa, raise the temperature to 130-140℃, keep the temperature for 12 h, cool to 80℃, add 40 g deionized water, 6 g allyloxy hydroxypropyl sulfonic acid sodium, catalyst p-toluene sulfonic acid, react for 3 h, add 1 g triethylamine to adjust the pH value to 7, cool to 50-60℃, vacuumize for 1-5 h, extract butanone to obtain an amphiphilic block oligomer, i.e. a reactive macromolecular surface active crosslinking agent;

[0045] (2) Mix 6 g reactive macromolecular surface active crosslinking agent, 130 g deionized water, 180 g butyl acrylate, 50 g methyl methacrylate, 10 g glycidyl methacrylate, 25 g allyl methacrylate, 15 g hydroxyethyl acrylate, 0.09 g 3-mercapto propionic acid isooctyl ester, 0.8 g potassium persulfate, and then emulsify to obtain a monomer pre-emulsion under high speed stirring;

[0046] (3) Heat 130 g deionized water to 80℃, add 40 g monomer pre-emulsion prepared in step (2), add 0.8 g potassium persulfate, react for 20 min, add the remaining monomer pre-emulsion dropwise within 4 h, keep the temperature at 80℃ for 1 h, cool to 60-65℃, add 0.5 g disodium hydroxyacetate sulfinate dropwise, after the dropwise addition is completed, keep the temperature at 60-65℃ for 30 min, then raise the temperature to 80℃ and keep for 1 h, then cool to below 45℃, add 5 g potassium hydroxide to adjust the pH value of the emulsion to 7-8, stir uniformly, filter the product, and obtain a water-based acrylate pressure-sensitive adhesive;

[0047] (4) Mix 25 g acrylic acid, 25 g styrene, 160 g isooctyl ester, 20 g methyl isobornyl ester, and 0.16 g azobis isobutylamide, add 1 / 3 of the mixture into a reactor, protect under nitrogen, control the temperature at 60℃, and react for 1 h, titrate the remaining 2 / 3 of the mixture, control the titration temperature at 60-65℃, and keep the temperature at 60-65℃ for 1 h after the titration is completed, and obtain a high-strength high-molecular-weight resin;

[0048] (5) Add 70 g high-strength high-molecular-weight resin into 600 g water-based acrylate pressure-sensitive adhesive, disperse under high speed by a dispersing disc, add 15 g nano-sized silicon dioxide and 25 g quartz sand, disperse for 30 min under high speed, then add 0.3 g tetrafunctional epoxy resin curing agent, and continue to stir for 5 min, and obtain a water-based sanding coating.

[0049] Example 3

[0050] (1) Put 100 g butanone into a reactor, when the temperature rises to 60℃, add 10 g glyceryl oleate, 5 g acryloyl morpholine, 0.7 g p-toluenesulfonic acid into the reactor in turn, vacuumize to 0.09 MPa, raise the temperature to 130-140℃, keep the temperature for 15 h, cool to 80℃, add 40 g deionized water, 7 g allyloxy hydroxypropyl sulfonic acid sodium, catalyst p-toluenesulfonic acid, react for 3 h, add 1 g triethylamine to adjust the pH value to 7, cool to 50-60℃, vacuumize for 1-5 h, extract butanone to obtain an amphiphilic block oligomer, i.e. a reactive macromolecular surface active crosslinking agent;

[0051] (2) Mix 10 g reactive macromolecular surface active crosslinking agent, 140 g deionized water, 180 g butyl acrylate, 60 g methyl methacrylate, 10 g glycidyl methacrylate, 20 g allyl methacrylate, 15 g hydroxyethyl acrylate, 0.06 g 3-mercapto propionic acid isooctyl ester, 0.75 g potassium persulfate, and then emulsify to obtain a monomer pre-emulsion under high speed stirring;

[0052] (3) Heat 140 g deionized water to 80℃, add 40 g monomer pre-emulsion prepared in step (2), add 0.75 g potassium persulfate, react for 20 min, drop the remaining monomer pre-emulsion in 4 h, keep the temperature at 80℃ for 1 h, cool to 60-65℃, drop 0.6 g disodium hydroxyacetate sulfinate, after dropping, keep the temperature at 60-65℃ for 30 min, then raise the temperature to 80℃ for 1 h, then cool to below 45℃, add 5 g potassium hydroxide to adjust the pH value of the emulsion to 7-8, stir uniformly, filter the product to obtain a water-based acrylate pressure-sensitive adhesive;

[0053] (4) Mix 20 g acrylic acid, 25 g styrene, 160 g isooctyl ester, 25 g methyl isobornyl ester, 0.16 g azobis isobutyl, add 1 / 3 of the mixture into a reactor, protect under nitrogen, control the temperature at 60℃, react for 1 h, drop the remaining 2 / 3 of the mixture, the dropping time is 3 h, the dropping temperature is controlled at 60-65℃, after dropping, keep the temperature at 60-65℃ for 1 h, to obtain a high-strength high-molecular-weight resin;

[0054] (5) Add 40 g high-strength high-molecular-weight resin into 600 g water-based acrylate pressure-sensitive adhesive, disperse under high speed by a dispersing disc, add 10 g nano-sized silicon dioxide and 20 g quartz sand, disperse for 30 min under high speed, then add 0.3 g tetrafunctional epoxy resin curing agent, continue to stir for 5 min, to obtain a water-based sanding coating.

[0055] Example 4

[0056] (1) Put 85 g butanone into a reactor, when the temperature rises to 60℃, add 10 g glyceryl oleate, 5 g acryloyl morpholine, 0.7 g p-toluene sulfonic acid into the reactor in turn, vacuumize to 0.09 MPa, raise the temperature to 130-140℃, keep the temperature for 10 h, cool to 80℃, add 40 g deionized water, 8 g allyloxy hydroxypropyl sulfonic acid sodium, catalyst p-toluene sulfonic acid, react for 2 h, add 1 g triethylamine to adjust the pH value to 7, cool to 50-60℃, vacuumize for 1-5 h, extract butanone, and obtain an amphiphilic block oligomer, i.e. a reactive macromolecular surface active crosslinking agent;

[0057] (2) Mix 8 g reactive macromolecular surface active crosslinking agent, 140 g deionized water, 170 g butyl acrylate, 60 g methyl methacrylate, 20 g glycidyl methacrylate, 20 g allyl methacrylate, 20 g hydroxyethyl acrylate, 0.09 g 3-mercapto propionic acid isooctyl ester, and 0.75 g potassium persulfate, and then emulsify to obtain a monomer pre-emulsion;

[0058] (3) Heat 140 g deionized water to 80℃, add 50 g monomer pre-emulsion prepared in step (2), add 0.75 g potassium persulfate, react for 20 min, drop the remaining monomer pre-emulsion in 3 h, keep the temperature at 80℃ for 1 h, cool to 60-65℃, drop 0.6 g disodium hydroxyacetate sulfinate, keep the temperature at 60-65℃ for 30 min after the dropping is completed, then raise the temperature to 80℃ and keep for 1 h, then cool to below 45℃, add 5 g potassium hydroxide to adjust the pH value of the emulsion to 7-8, stir uniformly, filter the product, and obtain a water-based acrylate pressure-sensitive adhesive;

[0059] (4) Mix 25 g acrylic acid, 25 g styrene, 160 g isooctyl ester, 15 g methyl isobornyl ester, and 0.19 g azobis isobutyl nitrite, add 1 / 3 of the mixture into a reactor, protect with nitrogen, control the temperature at 60℃, and react for 1 h, drop the remaining 2 / 3 of the mixture, control the dropping time at 3 h and the dropping temperature at 60-65℃, keep the temperature at 60-65℃ for 1 h after the dropping is completed, and obtain a high-strength high-molecular-weight resin;

[0060] (5) Add 50 g high-strength high-molecular-weight resin into 600 g water-based acrylate pressure-sensitive adhesive, disperse with a high-speed dispersing disc, add 10 g nano-sized silicon dioxide and 20 g quartz sand, disperse at high speed for 30 min, then add 0.3 g tetrafunctional epoxy resin curing agent, and continue to stir for 5 min, and obtain a water-based sanding coating.

[0061] Comparative Example 1

[0062] (1) Put 75 g butanone into the reactor, when the temperature rises to 60℃, add 10 g glyceryl oleate, 5 g acryloyl morpholine, 0.7 g p-toluene sulfonic acid into the reactor in turn, vacuumize to 0.09 MPa, raise the temperature to 130-140℃, keep the temperature for 12 h, cool to 80℃, add 40 g deionized water, 8 g allyloxy hydroxypropyl sulfonic acid sodium, catalyst p-toluene sulfonic acid, react for 3 h, add 1 g triethylamine to adjust the pH value to 7, cool to 50-60℃, vacuumize for 1-5 h, extract butanone to obtain the amphiphilic block oligomer, i.e. the reactive macromolecular surface active crosslinking agent;

[0063] (2) Mix 6 g reactive macromolecular surface active crosslinking agent, 140 g deionized water, 170 g butyl acrylate, 60 g methyl methacrylate, 20 g glycidyl methacrylate, 20 g allyl methacrylate, 20 g hydroxyethyl acrylate, 0.09 g 3-mercapto propionic acid isooctyl ester, 0.75 g potassium persulfate, and then emulsify to obtain the monomer pre-emulsion under high speed stirring;

[0064] (3) Heat 140 g deionized water to 80℃, add 50 g monomer pre-emulsion prepared in step (2), add 0.75 g potassium persulfate, react for 20 min, drop the remaining monomer pre-emulsion in 3 h, keep the temperature at 80℃ for 1 h, cool to 60-65℃, drop 0.6 g disodium hydroxyacetate sulfinate, after the dropping is completed, keep the temperature at 60-65℃ for 30 min, then raise the temperature to 80℃ for 1 h, then cool to below 45℃, add 5 g potassium hydroxide to adjust the pH value of the emulsion to 7-8, stir uniformly, filter the product to obtain the water-based acrylate pressure-sensitive adhesive;

[0065] (4) Take 600 g water-based acrylate pressure-sensitive adhesive, disperse under high speed by using a dispersion disc, add 8 g nano-sized silicon dioxide and 20 g quartz sand, disperse for 30 min under high speed, then add 0.3 g tetrafunctional epoxy resin curing agent, continue to stir for 5 min to obtain the water-based sanding coating.

[0066] Comparative Example 2

[0067] (1) Mix 10 g surface active crosslinking agent, 140 g deionized water, 170 g butyl acrylate, 60 g methyl methacrylate, 20 g glycidyl methacrylate, 20 g allyl methacrylate, 20 g hydroxyethyl acrylate, 0.09 g 3-mercapto propionic acid isooctyl ester, 0.75 g potassium persulfate, and then emulsify to obtain the monomer pre-emulsion under high speed stirring;

[0068] (2) 140 g of deionized water was heated to 80°C, 50 g of the monomer pre-emulsion prepared in step (1) was added, 0.75 g of potassium persulfate was added, and the reaction was carried out for 20 min. The remaining monomer pre-emulsion was added dropwise within 3 h, and the temperature was maintained at 80°C for 1 h. The temperature was then lowered to 60-65°C, 0.6 g of disodium hydroxyacetate sulfinate was added dropwise, and after the addition was completed, the temperature was maintained at 60-65°C for 30 min. The temperature was then raised to 80°C for 1 h, and then lowered to below 45°C. 5 g of potassium hydroxide was added to adjust the pH of the emulsion to 7-8, and then stirred uniformly. The product was filtered to obtain a water-based acrylic pressure-sensitive adhesive;

[0069] (3) 600 g of the water-based acrylic pressure-sensitive adhesive was dispersed by a dispersing disc at high speed, 8 g of nano-sized silicon dioxide and 20 g of quartz sand were added, and high-speed dispersion was carried out for 30 min. Then, 0.3 g of a tetra-functional epoxy resin curing agent was added, and stirring was continued for 5 min to obtain a water-based sanding coating.

[0070] Sample preparation method: The water-based sanding coating prepared in the examples was coated on a 40 μm thick polyester printing film, and the adhesive thickness was 3 μm. After drying and curing at 120°C for 2 min, a battery label sanding adhesive film was prepared. The wear resistance and adhesion were tested. Test method: The wear resistance was determined according to the "Rotary Abrasion Rubber Wheel Method" GB / T 1768-2006, and the adhesion was determined according to the "Paint Film Grating Test" GB / T 9286-1998;

[0071] The performance test results of examples 1-4 are shown in Table 1.

[0072] Table 1: Details of the wear resistance, adhesion and label wrapping of the water-based sanding coating

[0073]

[0074] From the above Table 1, it can be seen that the water-based sanding coating prepared in examples 1-4 has good wear resistance, and the mass loss is less than 10% tested by the rotary abrasion rubber wheel method. The adhesion is good, and the adhesion does not decrease after aging. The label wrapping performance is good. Comparative examples 1-2 do not have self-made reactive polymer surfactant crosslinking agent and high-strength high-molecular-weight resin, and the wear resistance, adhesion and label wrapping performance are not good. Therefore, this water-based sanding coating is suitable for the field of battery labels.

[0075] The water-based sanding coating can ensure the sanding effect while reducing the manufacturing cost because the diluent in the coating is water. It has good light transmittance and temperature resistance, and does not pollute the environment because it does not contain solvent.

[0076] The key to prepare water-based sanding coating is to synthesize reactive polymer surfactant crosslinking agent, and emulsify monomer to prepare water-resistant and weather-resistant water-based acrylic pressure-sensitive adhesive by soap-free emulsion polymerization. The reactive polymer surfactant crosslinking agent has good monomer emulsification performance, can be used alone to emulsify monomer, and is a high molecular polymer with large molecular weight, which is not easy to migrate to the surface of the adhesive film after aging, ensuring the bonding strength and water resistance of the pressure-sensitive adhesive. Then add high-strength high-molecular-weight resin, and synthesize resin with large molecular weight by bulk polymerization. The reaction soft monomer is isooctyl ester, which increases the non-polarity of the resin and thus increases the wettability of the adhesive and the label. Methyl isobutyl ester can improve the strength of the pressure-sensitive adhesive, i.e. wear resistance, due to its own benzene ring. Finally, add dispersant, filler and curing agent. The tetrafunctional epoxy curing agent has high reactivity with acrylic pressure-sensitive adhesive, and after crosslinking, the cohesive strength, heat resistance and aging resistance of the pressure-sensitive adhesive are significantly improved. The acrylic pressure-sensitive adhesive crosslinked and cured by it has basically no adhesion loss after aging at 70℃ for 96h.

Claims

1. A method for preparing a water-based matte coating for battery labels, characterized by: The preparation steps include: (1) Preparation of reactive polymer surfactant crosslinking agent Add butanone into the reactor, when the temperature rises to 60℃, add glyceryl oleate, acryloyl morpholine, catalyst, polymerization inhibitor into the reactor in sequence, vacuumize to 0.09MPa, raise the temperature to 130-140℃, keep the temperature for 10-15h, cool to 80℃, add deionized water, allyloxy hydroxypropyl sulfonic acid sodium, catalyst, react for 1-3h, add triethylamine to adjust the pH value to 7, cool to 50-60℃, vacuumize for 1-5h, extract butanone, to obtain amphiphilic block oligomer, namely reactive polymer surfactant crosslinking agent; (2) Preparation of monomer pre-emulsion Mix the reactive polymer surfactant crosslinking agent in step (1), part of deionized water, acrylate monomer, crosslinking monomer, chain transfer agent, oxidant, and then emulsify to obtain monomer pre-emulsion; (3) Preparation of water-based acrylate pressure-sensitive adhesive Heat the remaining deionized water to 80-85℃, add part of the monomer pre-emulsion prepared in step (2), add oxidant, react for 20min, add the remaining monomer pre-emulsion in 3-5h, keep the temperature at 80℃ for 1h, cool to 60-65℃, add reducing agent, keep the temperature at 60-65℃ for half an hour after the addition of reducing agent is completed, then raise the temperature to 80℃ for 1h, then cool to below 45℃, add pH regulator to adjust the pH value of the emulsion to 7-8, stir uniformly, filter the product, to obtain water-based acrylate pressure-sensitive adhesive; (4) Preparation of high-strength high-molecular-weight resin Mix acrylic acid, styrene, isooctyl ester, methyl isobornyl ester, initiator, add part of the mixed monomers into the reactor, protect with nitrogen, control the temperature at 60℃, react for 1h, add the remaining mixed monomers into the reactor, control the temperature at 60-65℃ during titration, keep the temperature at 60-65℃ for 1h after titration, to obtain high-strength high-molecular-weight resin; (5) Preparation of water-based sanding coating Add the high-strength high-molecular-weight resin prepared in step (4) into the water-based acrylate pressure-sensitive adhesive prepared in step (3), disperse with high-speed dispersion disc, add dispersant and filler, disperse for 30min, then add curing agent, continue to stir for 5min, to obtain water-based sanding coating.

2. The method of claim 1, wherein the water-based matte coating for battery labels is prepared by the steps of: The mass ratio of allyloxy hydroxypropyl sulfonic acid sodium, acryloyl morpholine, butanone, glyceryl oleate, catalyst in step (1) is 5-10:3-5:60-150:8-12:0.4-1.

2.

3. The method for preparing a water-based frosted coating for a battery label as described in claim 1, characterized in that: The catalyst in step (1) is p-toluenesulfonic acid.

4. The method for preparing a water-based frosted coating for a battery label as described in claim 1, characterized in that: The mass ratio of reactive polymer surfactant crosslinking agent, part of deionized water, acrylate monomer, crosslinking monomer, chain transfer agent, oxidant in step (2) is 1-10:100-150:200-300:10-20:0.03-0.2:0.5-1.

5. The method for preparing a water-based frosted coating for a battery label as described in claim 1, characterized in that: The acrylate monomer in step (2) is butyl acrylate, methyl methacrylate, glycidyl methacrylate, allyl methacrylate.

6. The method for preparing a water-based frosted coating for a battery label as described in claim 1, characterized in that: The crosslinking monomer in the step (2) is hydroxyethyl acrylate, the chain transfer agent is 3-mercapto propionic acid isooctyl ester, and the oxidant is potassium persulfate.

7. The method for preparing a water-based frosted coating for a battery label as described in claim 1, characterized in that: The pH regulator in the step (3) is potassium hydroxide, the reducing agent is hydroxyacetic acid disodium sulfinate, the oxidant is potassium persulfate, and the mass ratio of the oxidant, deionized water and monomer pre-emulsion is 0.5-1:100-150:30-50.

8. The method for preparing a water-based frosted coating for a battery label as described in claim 1, characterized in that: The mass ratio of acrylic acid, styrene, isooctyl ester, methyl isobornyl ester and initiator in the step (4) is 20-30:15-30:100-200:15-30:0.05-0.

2.

9. The method for preparing a water-based frosted coating for a battery label as described in claim 1, characterized in that: The initiator in the step (4) is azobis isobutylidene.

10. The method for preparing a water-based frosted coating for a battery label as described in claim 1, characterized in that: The dispersant in the step (5) is nano-sized silicon dioxide, the filler is quartz sand, and the curing agent is a tetra-functional epoxy resin curing agent.

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