CN116970345B - Application method of binder, carrier and battery - Google Patents

Application method of binder, carrier and battery Download PDF

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Publication number
CN116970345B
CN116970345B CN202311224153.XA CN202311224153A CN116970345B CN 116970345 B CN116970345 B CN 116970345B CN 202311224153 A CN202311224153 A CN 202311224153A CN 116970345 B CN116970345 B CN 116970345B
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Prior art keywords
parts
adhesive
carrier
chain segment
low
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CN116970345A (en
Inventor
曾锐明
王键
佟锐
陈绵锋
贾宝泉
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Shenzhen Perfect Power Technology Co ltd
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Shenzhen Perfect Power Technology Co ltd
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    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J4/00—Adhesives based on organic non-macromolecular compounds having at least one polymerisable carbon-to-carbon unsaturated bond ; adhesives, based on monomers of macromolecular compounds of groups C09J183/00 - C09J183/16
    • C09J4/06—Organic non-macromolecular compounds having at least one polymerisable carbon-to-carbon unsaturated bond in combination with a macromolecular compound other than an unsaturated polymer of groups C09J159/00 - C09J187/00
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J7/00—Adhesives in the form of films or foils
    • C09J7/20—Adhesives in the form of films or foils characterised by their carriers
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J7/00—Adhesives in the form of films or foils
    • C09J7/30—Adhesives in the form of films or foils characterised by the adhesive composition
    • C09J7/38—Pressure-sensitive adhesives [PSA]
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/054—Accumulators with insertion or intercalation of metals other than lithium, e.g. with magnesium or aluminium
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/058—Construction or manufacture
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/46—Separators, membranes or diaphragms characterised by their combination with electrodes
    • H01M50/461—Separators, membranes or diaphragms characterised by their combination with electrodes with adhesive layers between electrodes and separators
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J2203/00—Applications of adhesives in processes or use of adhesives in the form of films or foils
    • C09J2203/33—Applications of adhesives in processes or use of adhesives in the form of films or foils for batteries or fuel cells
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J2301/00—Additional features of adhesives in the form of films or foils
    • C09J2301/30—Additional features of adhesives in the form of films or foils characterized by the chemical, physicochemical or physical properties of the adhesive or the carrier
    • C09J2301/302—Additional features of adhesives in the form of films or foils characterized by the chemical, physicochemical or physical properties of the adhesive or the carrier the adhesive being pressure-sensitive, i.e. tacky at temperatures inferior to 30°C
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Abstract

The invention belongs to the field of new energy, and discloses an application method of an adhesive, wherein the adhesive comprises water and microspheres or microcapsules dispersed in the water; the microsphere or microcapsule consists of a hydrophilic chain segment of an outer layer, a low Tg chain segment of an inner layer and a photo-cleavable chain transfer agent connected with the hydrophilic chain segment and the low Tg chain segment; the Tg value of the low Tg chain segment is-60-0 ℃; the adhesive is coated on the carrier, and pressure is applied to the adhesive under the light condition meeting the light splitting requirement, so that the low Tg chain segment of the inner layer is spread on the carrier, and the purpose of bonding is realized. According to the method, under the conditions of illumination and pressurization, the microcapsule or microsphere structure is damaged, the overflow of the low Tg chain segment is realized, the bonding effect is achieved, the bonding at normal temperature can be realized based on the means, the bonding is not realized when the diaphragm is wound, the bonding is realized when the diaphragm is used, and the intelligent bonding effect is realized. Meanwhile, the invention also discloses a carrier and a battery.

Description

Application method of binder, carrier and battery
Technical Field
The invention belongs to the field of new energy, and particularly relates to an application method of an adhesive, a carrier and a battery.
Background
With the development of human society, the problems of energy shortage, environmental pollution and the like are increasingly serious, and in recent years, the lithium ion battery with high performance and low cost becomes a research and development hot spot facing the higher requirements of application fields of aerospace industry, high-end military equipment, long-endurance electric automobiles, portable electronic products and the like. The positive and negative electrode materials with high specific capacity are key factors for improving the energy density of the lithium ion battery.
Lithium ion batteries generally consist essentially of a positive electrode, a negative electrode, a separator, an electrolyte, and a battery housing, wherein the separator is one of the key inner layer components and is mainly used for separating the positive electrode from the negative electrode of the battery and preventing the positive electrode from being in contact with the negative electrode to cause short circuit. The separator used in the lithium ion battery at present is generally a polyolefin porous film, and because the melting point of the polyolefin porous film is lower than 200 ℃, when the temperature of the battery is increased due to internal or external factors, the polyolefin porous film can shrink or melt, so that positive and negative electrodes are directly contacted, the battery is short-circuited, and accidents such as combustion explosion and the like of the battery are caused.
In recent years, in order to increase the energy density of a battery, the compacted density of the positive and negative electrodes is also increased to be close to the limit, and the expansion of a pole piece, particularly a negative electrode, during the cycle of charge and discharge can cause deformation of the battery, seriously affecting the safety and reliability of the battery. On the other hand, as the capacity of the battery is increased, the area, the volume and the weight of the battery are also increased, and in the battery production process, the battery is often deformed and fluffy due to loose internal structure and low mechanical strength of the battery core, and even the serious problem that the battery cannot be put into a shell is caused.
In order to solve the above problems, attempts have been made to prepare ceramic/polymer composite separators by coating ceramic particles on the surface of a separator substrate using an adhesive, and it is desirable to reduce the thermal shrinkage of the separator by using the heat resistance of the ceramic particles, and to improve the adhesion between the separator and the electrode sheet interface by using a polymer, thereby achieving the purpose of preventing the occurrence of short-circuiting between the positive and negative electrodes of the battery and improving the hardness of the battery cell. However, these composite membranes still suffer from varying degrees of deficiency. For example, a composite separator comprising a separator, a ceramic coating and a polymer coating applied to the surface of the separator and/or the ceramic coating and distributed in islands and/or lines is disclosed. However, when the composite diaphragm is coated, the slurry is prepared by adopting organic solvents such as NMP, acetone and ethanol for multiple coating, so that the environment is polluted, the yield is reduced, the cost is increased due to complex process, and the problem is that the adhesiveness between the composite diaphragm and the pole piece is not high, and the hardness of the battery cell cannot be effectively improved. There have also been attempts to prepare a slurry of a fluoropolymer such as PVDF dissolved in an organic solvent such as NMP to coat the membrane substrate, and then wash the organic solvent such as NMP with water or other solvents to form a porous coating layer, and to manufacture such a composite membrane, a large amount of organic solvent is required, and a large amount of wastewater containing the organic solvent is generated, causing serious environmental pollution and also greatly increasing manufacturing costs. Still other people have introduced high Tg aqueous polyacrylate on ceramic coatings, such high Tg designs can prevent the separator from sticking between separators when wound, but require high temperatures (> 80 ℃) when used, which can affect the separator, and at the same time, do not achieve the effects of energy conservation and emission reduction.
The applicant previously proposed two patents:
prior art 1: CN116063641a discloses a preparation method of flame-retardant lithium battery positive electrode adhesive, which comprises the following steps: the microcapsule adhesive coated with the flame retardant is prepared by adopting an esterified parent solvent chain segment and then carrying out reversible addition fragmentation chain transfer polymerization.
The method is based on the pyrolysis under the high temperature condition, realizes the release of the solvent-philic chain segment, and further realizes the release of the flame retardant wrapped in the acrylic chain segment, thereby achieving the flame retardant purpose.
From the above analysis, it can be seen that: the high temperature can cause the loss of the performance of the diaphragm, and the adhesive which can be adhered at normal temperature is not beneficial to the rolling of the diaphragm.
Prior art 2: CN116003713a discloses a method for preparing an adhesive nano material with a hollow structure and application thereof. The method comprises the following steps: (1) Mixing 3- (benzylthio-thiocarbonylthio) propionic acid, a first soft monomer, a first hard monomer, an initiator and a first solvent for the first time, carrying out the reaction for the first time in inert atmosphere, and cooling to obtain a first reactant; (2) And (3) carrying out secondary mixing on the first reactant, the second hard monomer, the crosslinking monomer, the initiator and the second solvent obtained in the step (1), carrying out secondary reaction under inert atmosphere to obtain a second reactant, and then carrying out spray drying treatment on the second reactant to obtain the binder nanomaterial with the hollow structure.
The scheme adopts 3- (benzylthio-thiocarbonylthio) propionic acid to connect a hard monomer segment and a soft monomer segment (a solvent-philic segment), wherein the soft monomer is positioned on the surface of particles so as to form a better bonding effect.
The monomer of the solvent-philic chain segment is obtained by copolymerizing a hard monomer and a soft elastomer, and specifically comprises the following components: the first soft monomer comprises any one or a combination of at least two of isooctyl acrylate, acrylic acid, octyl acrylate, ethyl acrylate and butyl acrylate; the first hard monomer comprises any one or a combination of at least two of methacrylic acid, acrylamide or acrylonitrile;
the hard monomers of the core layer are: any one or a combination of at least two of styrene, methyl styrene, acrylonitrile, methacrylonitrile, acrylic acid, methacrylic acid, acrylamide, methacrylamide, methyl methacrylate, methyl acrylate, cyclohexyl acrylate or cyclohexyl methacrylate.
The scheme still does not solve the problem that the diaphragm is not sticky after being wound at normal temperature.
Therefore, the problem solved by the present project is: how to realize that the diaphragm is not sticky after being rolled up at normal temperature and exerts excellent cohesiveness and air permeability in the use process.
Disclosure of Invention
Aiming at the defects of the prior art, the invention aims to provide an application method of a binder, which adopts a photocleavable microcapsule or microsphere structure with a chain transfer agent, a low Tg chain segment and a hydrophilic chain segment, controls the Tg value of the low Tg chain segment, causes the microcapsule or microsphere structure to be destroyed under the conditions of illumination and pressurization, realizes the overflow of the low Tg chain segment, achieves the bonding effect, can realize the bonding at normal temperature based on the means, and realizes the effects that the separator is not bonded when being wound and bonded when being used, and has intelligent bonding effect.
Meanwhile, the invention also discloses a carrier and a battery.
In order to achieve the aim of the invention, the invention adopts the following technical scheme: a method of using a binder comprising water, microspheres or microcapsules dispersed in water; the microsphere or microcapsule consists of a hydrophilic chain segment of an outer layer, a low Tg chain segment of an inner layer and a photo-cleavable chain transfer agent connected with the hydrophilic chain segment and the low Tg chain segment; the Tg value of the low Tg chain segment is-60-0 ℃;
the adhesive is coated on the carrier, and pressure is applied to the adhesive under the light condition meeting the light splitting requirement, so that the low Tg chain segment of the inner layer is spread on the carrier, and the purpose of bonding is realized.
In some embodiments of the invention, the Tg value can be-60 ℃, -55 ℃, -50 ℃, -45 ℃, -40 ℃, -35 ℃, -30 ℃, -25 ℃, -20 ℃, -15 ℃, -10 ℃, -5 ℃ or 0 ℃;
the Tg value is selected so that the low Tg segment can tile, spread and exhibit cohesive forces at low temperatures when subjected to pressure suitable for commercial use. Too high a glass transition temperature will result in a failure to tile or a need to heat up to achieve a similar effect, which clearly goes beyond the basic intent of the present invention.
In the application method of the adhesive, the number of the carriers is two, and the adhesive is arranged between the two carriers; the pressure is applied to one or both of the carriers.
In the invention, the object of the carrier is a pole piece, a diaphragm and the like which are emphasized and protected; but the invention can be expanded to the aspects of soft package material aluminum plastic film of soft package battery, decoration composite board bonding, and the like.
In the application method of the adhesive, the carrier is a pole piece and a diaphragm.
In the application method of the binder, the final finished binder also contains a thickening agent, a wetting agent, a defoaming agent and an auxiliary binder, wherein the solid content of the binder is 8-12 wt%;
in conventional applications in the art, the solids content is typically 8wt%, 9wt%, 10wt%, 11wt% or 12wt%;
in some embodiments of the invention, the final finished binder contains microspheres or microcapsules in an amount of 7wt% to 10.5wt%;
preferably, the final binder contains 7.5-10wt% of microspheres or microcapsules;
preferably, the final binder contains 8-9 wt% of microspheres or microcapsules;
in some embodiments of the invention, the final finished binder contains 7wt%, 7.5wt%, 8wt%, 8.5wt%, 9wt%, 9.5wt%, 10wt%, 10.5wt%, 11wt%, 11.5wt% or 12wt% microspheres or microcapsules.
In some embodiments of the invention, the binder comprises 0.14wt% to 0.21wt% thickener; the thickener is selected from the following types: CMC2791, CMC2885, CMC1220;
in some embodiments of the invention, the binder comprises 0.07wt% to 0.11wt% of a wetting agent; the wetting agent is selected from the following types: BYK3457, BM1348, PE-100;
in some embodiments of the invention, the binder comprises 0.07wt% to 0.11wt% defoamer; the optional model of the defoamer is as follows: n345, YT-610, G2960;
in some embodiments of the invention, the binder comprises 0.70wt% to 1.05wt% of an auxiliary binder; the auxiliary adhesive is selected from the following types: SWA610, AWG101, SWA610B;
the surface density of the adhesive on the carrier is 0.4-0.6 g/m 2 ；
After coating, a heating temperature not exceeding thermal cracking is applied to remove some or all of the solvent.
As described in CN116063641a, the cracking temperature of the chain transfer agent of the present invention is 120 ℃, and the proposed heating temperature of the present invention is 50-70 ℃; the time is 20 s-60 s;
in the application method of the adhesive, the adhesive is coated on the diaphragm in advance and is wound up; the adhesive is not contacted with the light condition meeting the light splitting in the processes of coating the adhesive on the diaphragm, rolling the diaphragm, storing the diaphragm and unreeling the diaphragm.
In the above method for applying the adhesive, the chain transfer agent is 3- (benzylthio)Thiocarbonylthio) propanoic acid; the illumination conditions are as follows: the illumination wavelength is 465nm, and the illumination intensity is 10mW/cm 2 。
In the present invention, the proposed range of illumination wavelengths is 465nm; the recommended illumination intensity is 8-12W/cm 2 。
It should be noted that, since only 3- (benzylthio-thiocarbonylthio) propionic acid was tested for the moment, the applicant did not determine whether other trithioester chain transfer agents were cleavable under light irradiation and the parameters of cleavage, but the basic idea of the present invention should be to cover all schemes based on photocleavable trithioester chain transfer agents;
in the above binder application method, the low Tg segment is composed of polymerized units: the polymerization unit is one or more of isooctyl acrylate, acrylic acid, octyl acrylate, ethyl acrylate, butyl acrylate, styrene, methyl styrene, acrylonitrile, methacrylonitrile, acrylic acid, methacrylic acid, acrylamide, methacrylamide, methyl methacrylate, methyl acrylate, cyclohexyl acrylate or cyclohexyl methacrylate.
In the application method of the adhesive, the hydrophilic chain segment is polyethylene glycol monomethyl ether; the molecular weight of the polyethylene glycol monomethyl ether is 2000-5000.
In the application method of the adhesive, the low Tg chain segment consists of isooctyl acrylate, styrene, methacrylic acid and acrylamide; the weight ratio of the isooctyl acrylate to the styrene to the methacrylic acid to the acrylamide is 23-43: 5-25: 1:1, a step of;
the weight ratio of the hydrophilic chain segment to the chain transfer agent is 150-210:30;
the weight ratio of the hydrophilic chain segment to the chain transfer agent is 150-190:30;
more preferably, the weight ratio of the hydrophilic segment to the chain transfer agent is 150 to 180:30;
more preferably, the weight ratio of the hydrophilic segment to the chain transfer agent is 180:30;
the molecular weight of the polyethylene glycol monomethyl ether is preferably 2000.
In the application method of the adhesive, the preparation method of the adhesive comprises the following steps:
step 1: dispersing 3- (benzylthio-thiocarbonylthio) propionic acid, polyethylene glycol monomethyl ether, dicyclohexylcarbodiimide and 4-dimethylaminopyridine into anhydrous dichloromethane, and synthesizing to obtain an intermediate product;
step 2: dispersing the intermediate product, a polymerization monomer forming a low Tg chain segment and an initiator into water for polymerization to obtain the adhesive.
In the application method of the adhesive, the weight ratio of the 3- (benzylthio-thiocarbonylthio) propionic acid, polyethylene glycol monomethyl ether, dicyclohexylcarbodiimide and 4-dimethylaminopyridine is 30: 150-210: 20-40: 1 to 5;
the weight ratio of the intermediate product to the polymerized monomer is 10:20-50;
the step 2 adopts a soap-free emulsion polymerization method to carry out the reaction.
In the above-described method of applying the adhesive, the pressure is 0.1 to 2MPa, preferably 0.5 to 1.5MPa.
The invention also discloses a carrier, and the adhesive is coated on the carrier by adopting any one of the methods.
In the above carriers, the carriers are 2 sheets, wherein one of the carriers is a diaphragm, and the other carrier is a pole piece of the battery.
Finally, the invention also discloses a battery, which comprises a positive plate, a negative plate, a diaphragm and electrolyte; the separator and the positive electrode sheet or the negative electrode sheet are bonded by any of the methods described above.
In the above battery, the battery is a lithium ion battery or a sodium ion battery.
Compared with the prior art, the invention has the following beneficial effects:
according to the invention, a photocleavable microcapsule or microsphere structure with a chain transfer agent, a low Tg chain segment and a hydrophilic chain segment is adopted, the Tg value of the low Tg chain segment is controlled, so that the microcapsule or microsphere structure is destroyed under the conditions of illumination and pressurization, the overflow of the low Tg chain segment is realized, the bonding effect is achieved, the bonding at normal temperature can be realized based on the means, the bonding during the rolling of the diaphragm is realized, the bonding during the use of the diaphragm is realized, and the intelligent bonding effect is realized;
based on the scheme characteristics of the invention, the invention has the advantages of no damage to the performance of the diaphragm during bonding, low energy consumption, good air permeability and convenient processing.
Detailed Description
The technical scheme of the invention is further described by the following specific embodiments. It will be apparent to those skilled in the art that the examples are merely to aid in understanding the invention and are not to be construed as a specific limitation thereof.
Unless specifically stated otherwise, the parts of examples and comparative examples of the present invention are parts by weight;
the molecular weights of the present invention are all number average molecular weights, unless specifically stated otherwise;
under the condition that no special description is made, the weight ratio of the composite initiator is 1:1.
several experiments prove that the selection of the types of the initiators does not basically have decisive influence on the function implementation of the invention, and the water-soluble initiators can be applied to the invention, so that the invention does not emphasize the selection and the dosage of the initiators by additional examples, and conventional initiators such as redox initiation systems, oxidation initiation systems and the like used in the free radical initiation reaction are applicable to the invention.
The dehydrating agent and the catalyst can also be replaced in parallel by adopting the conventional practice of the invention without decisive influence on the functional implementation of the invention.
First part
This section mainly verifies the impact of low Tg segments of different glass transition temperatures, different hydrophilic segments, different amounts of chain transfer agent on product properties.
Example 1
The preparation of the binder is divided into two steps, wherein the chain transfer agent and the hydrophilic chain segment are prepared in the first step, and the low Tg chain segment is connected on the basis of the chain transfer agent and the hydrophilic chain segment in the second step;
specifically, the method comprises the following steps:
step 1: preparing materials according to the formula of a batching list, and reacting and purifying;
mixing and stirring the raw material (1) for 24 hours, then concentrating the mixture by rotary evaporation, adding the mixture into n-hexane, and collecting a polymer through precipitation reaction; redissolving and concentrating the polymer in dichloromethane solution, purifying by passing through a silica gel column, concentrating eluent, and finally drying in vacuum at 45 ℃ to obtain yellow powder;
step 2: preparing materials according to the formula of a batching list, performing polymerization reaction and drying;
uniformly mixing and stirring the raw material (2), introducing nitrogen for 30 minutes, heating a closed container to 70 ℃ for reaction for 8 hours, and performing dispersion polymerization; finally drying the mixture into powder by a nitrogen spray dryer to obtain the microcapsule adhesive.
The batching list is as follows:
30 parts of raw material (1)3- (benzylthio-thiocarbonylthio) propionic acid (BTPA) and 180 parts of polyethylene glycol monomethyl ether (molecular weight 2000);
23 parts of dicyclohexylcarbodiimide (dehydrating agent);
1.3 parts of 4-dimethylaminopyridine (catalyst);
1000 parts of anhydrous dichloromethane;
10 parts of a product obtained in the step (2) of raw materials, 43 parts of isooctyl acrylate, 5 parts of styrene, 1 part of methacrylic acid and 1 part of acrylamide, wherein the theoretical Tg is-55 ℃;
0.15 parts of potassium persulfate/ammonium persulfate;
90 parts of water.
Example 2
The preparation method of reference example 1 is different in the formulation, specifically the recipe can be seen as recipe:
30 parts of raw material (1)3- (benzylthio-thiocarbonylthio) propionic acid (BTPA) and 150 parts of polyethylene glycol monomethyl ether (molecular weight 2000);
23 parts of dicyclohexylcarbodiimide (dehydrating agent);
1.3 parts of 4-dimethylaminopyridine (catalyst);
1000 parts of anhydrous dichloromethane;
10 parts of a product obtained in the step (2) of raw materials, 43 parts of isooctyl acrylate, 5 parts of styrene, 1 part of methacrylic acid and 1 part of acrylamide, wherein the theoretical Tg is-55 ℃;
0.15 parts of potassium persulfate/ammonium persulfate;
90 parts of water.
Example 3
The preparation method of reference example 1 is different in the formulation, specifically the recipe can be seen as recipe:
30 parts of raw material (1)3- (benzylthiocarbonylthio) propionic acid (BTPA) and 210 parts of polyethylene glycol monomethyl ether (molecular weight 2000);
23 parts of dicyclohexylcarbodiimide (dehydrating agent);
1.3 parts of 4-dimethylaminopyridine (catalyst);
1000 parts of anhydrous dichloromethane;
10 parts of a product obtained in the step (2) of raw materials, 43 parts of isooctyl acrylate, 5 parts of styrene, 1 part of methacrylic acid and 1 part of acrylamide, wherein the theoretical Tg is-55 ℃;
0.15 parts of potassium persulfate/ammonium persulfate;
90 parts of water.
Example 4
The preparation method of reference example 1 is different in the formulation, specifically the recipe can be seen as recipe:
30 parts of raw material (1)3- (benzylthiocarbonylthio) propionic acid (BTPA) and 210 parts of polyethylene glycol monomethyl ether (molecular weight 2000);
23 parts of dicyclohexylcarbodiimide (dehydrating agent);
1.3 parts of 4-dimethylaminopyridine (catalyst);
1000 parts of anhydrous dichloromethane;
10 parts of a product obtained in the step (2) of raw materials, 33 parts of isooctyl acrylate, 15 parts of styrene, 1 part of methacrylic acid and 1 part of acrylamide, wherein the theoretical Tg is-31 ℃;
0.15 parts of potassium persulfate/ammonium persulfate;
90 parts of water.
Example 5
The preparation method of reference example 1 is different in the formulation, specifically the recipe can be seen as recipe:
30 parts of raw material (1)3- (benzylthiocarbonylthio) propionic acid (BTPA) and 210 parts of polyethylene glycol monomethyl ether (molecular weight 2000);
23 parts of dicyclohexylcarbodiimide (dehydrating agent);
1.3 parts of 4-dimethylaminopyridine (catalyst);
1000 parts of anhydrous dichloromethane;
10 parts of a product of the step one of the raw material (2), 23 parts of isooctyl acrylate, 25 parts of styrene, 1 part of methacrylic acid and 1 part of acrylamide, wherein the theoretical Tg is-1 ℃;
0.15 parts of potassium persulfate/ammonium persulfate;
90 parts of water.
Example 6
The preparation method of reference example 1 is different in the formulation, specifically the recipe can be seen as recipe:
30 parts of raw material (1)3- (benzylthiocarbonylthio) propionic acid (BTPA) and 210 parts of polyethylene glycol monomethyl ether (molecular weight 2000);
23 parts of dicyclohexylcarbodiimide (dehydrating agent);
1.3 parts of 4-dimethylaminopyridine (catalyst);
1000 parts of anhydrous dichloromethane;
10 parts of a product obtained in the step (2) of raw materials, 48 parts of butyl acrylate, 1 part of acrylic acid and 1 part of acrylamide, wherein the theoretical Tg is-51 ℃;
0.15 parts of potassium persulfate/ammonium persulfate;
90 parts of water.
Example 7
The preparation method of reference example 1 is different in the formulation, specifically the recipe can be seen as recipe:
30 parts of raw material (1)3- (benzylthio-thiocarbonylthio) propionic acid (BTPA), and 210 parts of polyethylene glycol monomethyl ether (molecular weight 2000) respectively;
23 parts of dicyclohexylcarbodiimide (dehydrating agent);
1.3 parts of 4-dimethylaminopyridine (catalyst);
1000 parts of anhydrous dichloromethane;
10 parts of a product obtained in the step (2), 34 parts of butyl acrylate, 14 parts of acrylonitrile, 1 part of acrylic acid and 1 part of acrylamide, wherein the theoretical Tg is-28 ℃;
0.15 parts of potassium persulfate/ammonium persulfate;
90 parts of water.
Example 8
The preparation method of reference example 1 is different in the formulation, specifically the recipe can be seen as recipe:
30 parts of raw material (1)3- (benzylthiocarbonylthio) propionic acid (BTPA) and 210 parts of polyethylene glycol monomethyl ether (molecular weight 2000);
23 parts of dicyclohexylcarbodiimide (dehydrating agent);
1.3 parts of 4-dimethylaminopyridine (catalyst);
1000 parts of anhydrous dichloromethane;
10 parts of a product obtained in the step (2), 24 parts of butyl acrylate, 24 parts of acrylonitrile, 1 part of acrylic acid and 1 part of acrylamide, wherein the theoretical Tg is-1 ℃;
0.15 parts of potassium persulfate/ammonium persulfate;
90 parts of water.
Example 9
Substantially as in example 4, except that: the polyethylene glycol monomethyl ether consists of polyethylene glycol monomethyl ether with molecular weight of 2000 and polyethylene glycol monomethyl ether with molecular weight of 5000, wherein the dosage of the two is 105 parts respectively and 210 parts in total.
Example 10
Substantially as in example 4, except that: the dosage of the polymerization monomer is halved, the proper amount of the initiator is halved, the water is halved, and a specific formula can be shown as a batching list:
30 parts of raw material (1)3- (benzylthiocarbonylthio) propionic acid (BTPA) and 210 parts of polyethylene glycol monomethyl ether (molecular weight 2000);
23 parts of dicyclohexylcarbodiimide (dehydrating agent);
1.3 parts of 4-dimethylaminopyridine (catalyst);
1000 parts of anhydrous dichloromethane;
10 parts of a product of the step one of the raw material (2), 16.5 parts of isooctyl acrylate, 7.5 parts of styrene, 0.5 part of methacrylic acid and 0.5 part of acrylamide, wherein the theoretical Tg is-55 ℃;
0.1 part of potassium persulfate/ammonium persulfate;
50 parts of water.
Example 11
Generally as in example 6, the formulation is different in that the recipe is specifically seen as recipe:
30 parts of raw material (1)3- (benzylthio-thiocarbonylthio) propionic acid (BTPA) and 180 parts of polyethylene glycol monomethyl ether (molecular weight 2000);
23 parts of dicyclohexylcarbodiimide (dehydrating agent);
1.3 parts of 4-dimethylaminopyridine (catalyst);
1000 parts of anhydrous dichloromethane;
10 parts of a product obtained in the step (2) of raw materials, 48 parts of butyl acrylate, 1 part of acrylic acid and 1 part of acrylamide, wherein the theoretical Tg is-51 ℃;
0.15 parts of potassium persulfate/ammonium persulfate;
90 parts of water.
Example 12
The procedure is substantially as in example 1, except that the formulation of step 2, in particular the recipe, can be seen as recipe:
10 parts of a product obtained in the step (2) of raw materials, 40.5 parts of isooctyl acrylate, 7.5 parts of styrene, 1 part of methacrylic acid and 1 part of acrylamide, wherein the theoretical Tg is-50 ℃;
0.15 parts of potassium persulfate/ammonium persulfate;
90 parts of water.
Example 13
The procedure is substantially as in example 1, except that the formulation of step 2, in particular the recipe, can be seen as recipe:
10 parts of a product obtained in the step (2) of raw materials, 38.5 parts of isooctyl acrylate, 9.5 parts of styrene, 1 part of methacrylic acid and 1 part of acrylamide, wherein the theoretical Tg is-45 ℃;
0.15 parts of potassium persulfate/ammonium persulfate;
90 parts of water.
Example 14
The procedure is substantially as in example 1, except that the formulation of step 2, in particular the recipe, can be seen as recipe:
10 parts of a product obtained in the step (2) of raw materials, 36.5 parts of isooctyl acrylate, 11.5 parts of styrene, 1 part of methacrylic acid and 1 part of acrylamide, wherein the theoretical Tg is-40 ℃;
0.15 parts of potassium persulfate/ammonium persulfate;
90 parts of water.
Example 15
The procedure is substantially as in example 1, except that the formulation of step 2, in particular the recipe, can be seen as recipe:
10 parts of a product obtained in the step (2) of raw materials, 33 parts of isooctyl acrylate, 15 parts of styrene, 1 part of methacrylic acid and 1 part of acrylamide, wherein the theoretical Tg is-31 ℃;
0.15 parts of potassium persulfate/ammonium persulfate;
90 parts of water.
Comparative example 1
1.4 parts of 3- (benzylthio-thiocarbonylthio) propionic acid (BTPA), 0.05 part of sodium dodecyl sulfonate, 10 parts of polyethylene glycol monomethyl ether methacrylate (with a molecular weight of 2000), 43 parts of isooctyl acrylate, 5 parts of styrene, 1 part of methacrylic acid, 1 part of acrylamide and 140 parts of deionized water are emulsified in a pre-emulsification kettle, transferred to the reaction kettle, 0.18 part of potassium persulfate is added, and the reaction is stopped after heating for 10 hours.
Comparative example 2
1.4 parts of 3- (benzylthio-thiocarbonylthio) propionic acid (BTPA), 0.05 part of sodium dodecyl sulfonate, 10 parts of polyethylene glycol monomethyl ether methacrylate (with a molecular weight of 2000), 34 parts of butyl acrylate, 14 parts of acrylonitrile, 1 part of acrylic acid, 1 part of acrylamide and 140 parts of deionized water are emulsified in a pre-emulsification kettle, transferred to the reaction kettle, 0.18 part of potassium persulfate is added, and the reaction is stopped after heating for 10 hours.
Application example 1
Preparation of the adhesive: 100 parts of the product obtained in the examples and comparative examples are added to a high-speed stirrer, 2 parts of thickener (CMC 1220), 1 part of wetting agent (BYK 3457), 1 part of defoamer (N345), 10 parts of auxiliary binder (SWA 610) are added, deionized water is used for diluting to 10% solid content, and the mixture is stirred for 30min and discharged to obtain a binder A.
And (3) rolling a diaphragm: adhesive A was applied to the separator and wound up in an amount of 0.5g/m areal density 2 Baking at 50 ℃ for 30s;
pole piece and diaphragm combination: the diaphragm is placed on a lower pressing plate of a cold press, the negative electrode plate is placed on the diaphragm (the coating of the negative electrode plate faces the diaphragm), the diaphragm is pressed for 60 seconds under the pressure of 1MPa, and the sample is taken down.
Performance testing
The air permeability test method comprises the following steps: the air permeability of the membrane is measured by a membrane air permeability tester.
Test method of peel strength: the stainless steel plate and the current collector were fixed to a jig of a peel force tester, and 180-degree peel test was performed at a speed of 10mm/min under a load of 10N.
Test results
The samples of examples and comparative examples were coated, wound and compounded using the application examples;
the peel strength test comprises the peel strength of the non-radiative pole piece and the diaphragm after being compounded and the peel strength of the pole piece and the diaphragm after being radiated after being compounded;
the air permeability test is the air permeability test result after the pole piece and the diaphragm are compounded.
Test results are shown in Table 1 below
Air permeability (s/100 mL) Winding and bonding Non-radiative peel strength (N/m) Radiation peel strength (N/m)
Example 1 241 Without any means for 0 12.1
Example 2 248 Has the following components 0.2 8.3
Example 3 256 Without any means for 0 10.1
Example 4 251 Without any means for 0 8.9
Example 5 249 Without any means for 0 5.4
Example 6 261 Without any means for 0 8.9
Example 7 256 Without any means for 0 5.1
Example 8 271 Without any means for 0 3.1
Example 9 263 Without any means for 0 8.5
Example 10 255 Without any means for 0 3.5
Example 11 258 Without any means for 0 7.5
Example 12 248 Without any means for 0 11.8
Example 13 246 Without any means for 0 11.6
Example 14 247 Without any means for 0 11.1
Example 15 253 Without any means for 0 9.4
Comparative example 1 261 Has the following components 0.3 0.3
Comparative example 2 271 Has the following components 0.1 0.1
Analysis of results:
1. it can be seen from examples 1 to 15 and comparative examples 1 and 2 that the aqueous binder does not generate significant adhesion without heating, whether or not with radiation;
in examples 1 to 15, the water content in the aqueous binder was previously removed by encapsulation with microcapsules and drying, and the binder overflowed from the capsules and spread under irradiation and pressure, and the binding operation was completed without heating during the construction.
The characteristics are particularly suitable for normal-temperature rolling and normal-temperature radiation construction operation of the diaphragm, and the condition that the diaphragm is damaged due to the fact that the conventional water-based adhesive needs to be heated to generate adhesive force is avoided.
2. It can be seen from examples 1 to 3 that when the hydrophilic segment polyethylene glycol monomethyl ether is increased or decreased, there is a certain influence on the air permeability and the cohesive force, and the possible reason is that when the hydrophilic segment is too many, that is, the high Tg segment is too many, the amount of the polymer in the single microcapsule is reduced, the structure is too stable, and further, the performances such as uniformity and the like are damaged when the hydrophobic binder is tiled, and further, the air permeability is reduced, and the viscosity is obviously reduced.
Too few hydrophilic chain segments, namely too few high Tg chain segments, lead to large film formation of the low Tg chain segments on the diaphragm, further lead to obvious deterioration of air permeability, meanwhile, the reduction of the hydrophilic chain segments can lead to unstable structure, and the diaphragm can have weak adhesive force when being wound;
3. it is seen from examples 1 and 12 to 15 that the gradual increase in the glass transition temperature brings about a decrease in the adhesion and a decrease in the air permeability;
similar rules are also exhibited in examples 3 to 5 and examples 6 to 8.
Meanwhile, it is apparent from examples 1, 12 to 15 and 3 to 5 that the air permeability is mainly affected by the hydrophilic segment and the chain transfer agent when the types of monomers are uniform.
As can be seen from the lateral comparison of examples 3 to 5 and examples 6 to 8, the air permeability is significantly affected by the selection of monomer types under the condition that the hydrophilic chain segments and the chain transfer agent are the same; when the glass transition temperatures are similar, the air permeability of examples 3 to 5 is significantly better;
4. example 9, example 10 each investigated the effect of a combination of different hydrophilic segments, different amounts of low Tg segments;
in example 11, the combination of monomers of example 6 and the chain transfer agent of example 1, hydrophilic segment, the adhesive properties of which are not as expected to be better than those of example 6, are used, which is illustrated from one side by the selection of the type of hydrophilic segment and the selection of the amount of low Tg segment to have a certain intrinsic synergistic mechanism, the different low Tg segments being required to match the combination of hydrophilic segment and chain transfer agent in the appropriate proportions;
as can be seen from the analysis of the above examples and comparative examples, the invention can realize the purpose of normal temperature rolling without sticking and heating during construction; the air permeability of the system is closely related to the proportion of the monomer selection, the hydrophilic chain segment and the chain transfer agent; the viscosity is closely related not only to the glass transition temperature but also to the choice of the ratio of hydrophilic segment to chain transfer agent. During the construction process we recommend the formulation selection of example 1.
Second part
It was confirmed by experiments in the first part that the object of the present invention is completely achieved when the glass transition temperature is lower than 0 ℃. And the examples 3-5 and 6-8 prove that the stripping force and the air permeability are in a better state when the glass transition temperature is lower, so that the influence of the selection of the core layer monomer on the performance is mainly studied in the part under the condition that the glass transition temperature is between minus 30 ℃ and minus 50 ℃.
The difference compared to the conventional chain transfer agent based microcapsule structure (CN 116003713 a) is: the case requires the microcapsules to be ruptured upon bonding to enable release of the binder; experiments prove that the state of the non-crosslinked polymer inside the capsule, the unfolded state after rupture and the use of the monomer are closely related.
This section was tested using the system of example 1 as a benchmark.
Specific examples are as follows:
example 16
In general, as in example 1, styrene was replaced with methyl methacrylate to give a Tg of-55 ℃.
30 parts of raw material (1)3- (benzylthio-thiocarbonylthio) propionic acid (BTPA) and 180 parts of polyethylene glycol monomethyl ether (molecular weight 2000);
23 parts of dicyclohexylcarbodiimide (dehydrating agent);
1.3 parts of 4-dimethylaminopyridine (catalyst);
1000 parts of anhydrous dichloromethane;
10 parts of a product obtained in the step (2), 43 parts of isooctyl acrylate, 5 parts of methyl methacrylate, 1 part of methacrylic acid and 1 part of acrylamide, wherein the theoretical Tg is-55 ℃;
0.15 parts of potassium persulfate/ammonium persulfate;
90 parts of water.
Example 17
In general, as in example 1, styrene was replaced with acrylonitrile to give a Tg of-55 ℃.
30 parts of raw material (1)3- (benzylthio-thiocarbonylthio) propionic acid (BTPA) and 180 parts of polyethylene glycol monomethyl ether (molecular weight 2000);
23 parts of dicyclohexylcarbodiimide (dehydrating agent);
1.3 parts of 4-dimethylaminopyridine (catalyst);
1000 parts of anhydrous dichloromethane;
10 parts of a product obtained in the step (2) of raw materials, 43 parts of isooctyl acrylate, 5 parts of acrylonitrile, 1 part of methacrylic acid and 1 part of acrylamide, wherein the theoretical Tg is-55 ℃;
0.15 parts of potassium persulfate/ammonium persulfate;
90 parts of water.
Example 18
In the same manner as in example 1, methacrylic acid was removed and the amount of acrylamide was increased to 2 parts.
30 parts of raw material (1)3- (benzylthio-thiocarbonylthio) propionic acid (BTPA) and 180 parts of polyethylene glycol monomethyl ether (molecular weight 2000);
23 parts of dicyclohexylcarbodiimide (dehydrating agent);
1.3 parts of 4-dimethylaminopyridine (catalyst);
1000 parts of anhydrous dichloromethane;
10 parts of a product obtained in the step (2) of raw materials, 43 parts of isooctyl acrylate, 5 parts of styrene and 2 parts of acrylamide, wherein the theoretical Tg is-55 ℃;
0.15 parts of potassium persulfate/ammonium persulfate;
90 parts of water.
Example 19
In the same manner as in example 1, acrylamide was removed and the amount of methacrylic acid was increased to 2 parts.
30 parts of raw material (1)3- (benzylthio-thiocarbonylthio) propionic acid (BTPA) and 180 parts of polyethylene glycol monomethyl ether (molecular weight 2000);
23 parts of dicyclohexylcarbodiimide (dehydrating agent);
1.3 parts of 4-dimethylaminopyridine (catalyst);
1000 parts of anhydrous dichloromethane;
10 parts of a product obtained in the step (2) of raw materials, 43 parts of isooctyl acrylate, 5 parts of styrene and 2 parts of methacrylic acid, wherein the theoretical Tg is-55 ℃;
0.15 parts of potassium persulfate/ammonium persulfate;
90 parts of water.
Comparative example 3
0.05 part of sodium dodecyl sulfate, 43 parts of isooctyl acrylate, 5 parts of styrene, 1 part of methacrylic acid and 1 part of acrylamide are emulsified in a pre-emulsifying kettle, 140 parts of deionized water are transferred to a reaction kettle, 0.18 part of potassium persulfate is added, and the reaction is stopped after heating for 10 hours.
Comparative example 4
0.05 part of sodium dodecyl sulfonate, 43 parts of isooctyl acrylate, 5 parts of methyl methacrylate, 1 part of methacrylic acid, 1 part of acrylamide and 140 parts of deionized water are emulsified in a pre-emulsification kettle, transferred to a reaction kettle, added with 0.18 part of potassium persulfate, heated and reacted for 10 hours, and the reaction is stopped.
Comparative example 5
0.05 part of sodium dodecyl sulfate, 43 parts of isooctyl acrylate, 5 parts of acrylonitrile, 1 part of methacrylic acid and 1 part of acrylamide are emulsified in 140 parts of deionized water in a pre-emulsification kettle, then the emulsified mixture is transferred to a reaction kettle, 0.18 part of potassium persulfate is added, and the reaction is stopped after heating for 10 hours.
Comparative example 6
0.05 part of sodium dodecyl sulfate, 43 parts of isooctyl acrylate, 5 parts of styrene, 2 parts of acrylamide and 140 parts of deionized water are emulsified in a pre-emulsification kettle, then transferred to a reaction kettle, 0.18 part of potassium persulfate is added, and the temperature is raised for reaction for 10 hours, and the reaction is stopped.
Comparative example 7
0.05 part of sodium dodecyl sulfate, 43 parts of isooctyl acrylate, 5 parts of styrene, 2 parts of methacrylic acid and 140 parts of deionized water are emulsified in a pre-emulsification kettle, then transferred to a reaction kettle, 0.18 part of potassium persulfate is added, and the reaction is stopped after heating up for 10 hours.
Application example 2
Preparation of the adhesive: 100 parts of the product obtained in examples 11 to 14 and comparative examples 3 to 8 were added to a high-speed mixer, 2 parts of thickener (CMC 1220), 1 part of wetting agent (BYK 3457), 1 part of defoamer (N345), 10 parts of auxiliary binder (SWA 610), diluted to 10% solids with deionized water, stirred for 30min and discharged to obtain binder A.
And (3) rolling a diaphragm: adhesive A was applied to the separator and wound up in an amount of 0.5g/m areal density 2 Baking at 50 ℃ for 30s;
pole piece and separator composite as referred to in examples 11-14: the diaphragm is placed on a lower pressing plate of a cold press, the negative electrode plate is placed on the diaphragm (the coating of the negative electrode plate faces the diaphragm), the diaphragm is pressed for 60 seconds under the pressure of 1MPa, and the sample is taken down.
Compounding of the pole piece and separator referred to in comparative examples 3-8: the diaphragm is placed on a lower pressing plate of a cold press, a negative electrode plate is placed on the diaphragm (a negative electrode plate coating faces the diaphragm), the diaphragm is pressed for 60 seconds at the temperature of 100 ℃ and the pressure of 1MPa, and a sample is taken down.
The performance test in this section only considers air permeability and peel strength to investigate the variation in performance trend of the copolymer product in different systems.
The results are shown in Table 2 below:
air permeability (s/100 mL) Peel strength (N/m)
Example 1 241 12.1
Example 16 254 11.1
Example 17 255 10.9
Example 18 258 11.4
Example 19 242 9.6
Comparative example 3 250 11.6
Comparative example 4 255 10.8
Comparative example 5 251 11.3
Comparative example 6 257 11.2
Comparative example 7 246 11.7
Analysis of results:
1. it is seen from examples 1 and 16 to 17 that changing the kind of the hard monomer significantly reduces the air permeability and the adhesion to some extent;
it can be seen from examples 1 and 18 to 19 that changing the selection of soft monomers such as methacrylic acid and acrylamide can significantly affect the breathability or the adhesion;
2. as can be seen from comparative examples 3 to 5, the selection of the monomers and the selection of the proportions of example 1 of the present invention can maintain relatively good air permeability and adhesion in the general emulsification reaction, similar to the trends of examples 1 and examples 16 to 17 of the present invention, but the use of the hydrophilic segment and chain transfer agent of the present invention optimizes the properties of the product, possibly for one or both of two reasons: 1. the use of hydrophilic segments, chain transfer agents, affects the properties of the binder in some way; 2. the separator is damaged by the high temperature for a long time, and even if the adhesive has excellent performance, the adhesive cannot be completely displayed in the test.
3. It can be seen from comparative examples 3, 6 and 7 that the effect of the conventional emulsification system on breathability and cohesiveness is not significant when the soft monomer is changed; in another aspect, when the strategy of the invention is selected, the selection of monomers and the selection of proportions are more severe, and the monomer can be obtained through repeated experiments.
The applicant states that the process of the invention is illustrated by the above examples, but the invention is not limited to the above process steps, which do not mean that the invention must be carried out in dependence on the above process steps. It should be apparent to those skilled in the art that any modification of the present invention, equivalent substitution of selected raw materials, addition of auxiliary components, selection of specific modes, etc. fall within the scope of the present invention and the scope of disclosure.

Claims (14)

1. A method of using a binder, wherein the binder comprises water, microspheres or microcapsules dispersed in water; the microsphere or microcapsule consists of a hydrophilic chain segment of an outer layer, a low Tg chain segment of an inner layer and a photo-cleavable chain transfer agent connected with the hydrophilic chain segment and the low Tg chain segment; the Tg value of the low Tg chain segment is-60-0 ℃; the chain transfer agent is 3- (benzylthio-thiocarbonylthio) propionic acid; the hydrophilic chain segment is polyethylene glycol monomethyl ether; the molecular weight of the polyethylene glycol monomethyl ether is 2000-5000; the low Tg segment is comprised of polymerized units; the polymerization unit is one or more of isooctyl acrylate, acrylic acid, octyl acrylate, ethyl acrylate, butyl acrylate, styrene, methyl styrene, acrylonitrile, methacrylonitrile, methacrylic acid, acrylamide, methacrylamide, methyl methacrylate, methyl acrylate, cyclohexyl acrylate or cyclohexyl methacrylate;
the adhesive is coated on the carrier, and pressure is applied to the adhesive under the light condition meeting the light splitting requirement, so that the low Tg chain segment of the inner layer is spread on the carrier, and the purpose of bonding is realized.
2. The method of claim 1, wherein the carrier is two pieces, and the adhesive is disposed between the two pieces of carrier; the pressure is applied to one or both of the carriers.
3. The method of claim 2, wherein the carrier is a pole piece and a membrane.
4. The method for applying the adhesive according to claim 3, wherein the adhesive further comprises a thickener, a wetting agent, a defoaming agent and an auxiliary adhesive, and the solid content of the adhesive is 8-12 wt%;
the surface density of the adhesive on the carrier is 0.4-0.6 g/m 2 ；
After coating, the heating temperature not exceeding thermal cracking is applied to remove all solvent.
5. The method of applying an adhesive according to claim 4, wherein the adhesive is pre-coated on a separator and wound up; the adhesive is not contacted with the light condition meeting the light splitting in the processes of coating the adhesive on the diaphragm, rolling the diaphragm, storing the diaphragm and unreeling the diaphragm.
6. The method of claim 1, wherein the lighting conditions are: the illumination wavelength is 465nm, and the illumination intensity is 10mW/cm 2 。
7. The method of claim 1, wherein the low Tg segment is comprised of isooctyl acrylate, styrene, methacrylic acid, acrylamide; the weight ratio of the isooctyl acrylate to the styrene to the methacrylic acid to the acrylamide is 23-43: 5-25: 1:1, a step of;
the weight ratio of the hydrophilic chain segment to the chain transfer agent is 150-210:30.
8. The method for applying the adhesive according to claim 1, wherein the adhesive is prepared by the following steps:
step 1: dispersing 3- (benzylthio-thiocarbonylthio) propionic acid, polyethylene glycol monomethyl ether, dicyclohexylcarbodiimide and 4-dimethylaminopyridine into anhydrous dichloromethane, and synthesizing to obtain an intermediate product;
step 2: dispersing the intermediate product, a polymerization monomer forming a low Tg chain segment and an initiator into water for polymerization to obtain the adhesive.
9. The method for applying the adhesive according to claim 8, wherein the weight ratio of the 3- (benzylthio-thiocarbonylthio) propionic acid, polyethylene glycol monomethyl ether, dicyclohexylcarbodiimide and 4-dimethylaminopyridine is 30: 150-210: 20-40: 1 to 5;
the weight ratio of the intermediate product to the polymerized monomer is 10:20-50;
the step 2 adopts a soap-free emulsion polymerization method to carry out the reaction.
10. The method according to any one of claims 1 to 9, wherein the pressure is 0.1 to 2MPa.
11. A carrier, characterized in that it is obtained by applying a binder to a carrier by a method according to any one of claims 1-10.
12. The carrier of claim 11, wherein the carrier is 2 sheets, one of the sheets being a separator and the other sheet being a battery pole piece.
13. The battery is characterized by comprising a positive plate, a negative plate, a diaphragm and electrolyte; the separator and the positive electrode sheet or the negative electrode sheet are bonded by the method according to any one of claims 1 to 10.
14. The battery of claim 13, wherein the battery is a lithium ion battery or a sodium ion battery.
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Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH10195152A (en) * 1996-12-27 1998-07-28 Kazunori Kataoka Core-shell microsphere and its production
JP2007099929A (en) * 2005-10-05 2007-04-19 Dainippon Ink & Chem Inc Hydrophilic colloidal particle and method for producing the same
CN101245120A (en) * 2008-03-17 2008-08-20 烟台大学 Process for producing cross-linked polymer microsphere with even grain diameter
CN115368518A (en) * 2022-07-15 2022-11-22 西南石油大学 Colloidal particle emulsifier and preparation method and application thereof
CN116063641A (en) * 2023-02-08 2023-05-05 深圳好电科技有限公司 Flame-retardant lithium battery anode adhesive and preparation method thereof
CN116463086A (en) * 2023-04-27 2023-07-21 衡水中裕铁信防水技术有限公司 Microcapsule slow-release self-adhesive and slow-release self-adhesive waterproof coiled material

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH10195152A (en) * 1996-12-27 1998-07-28 Kazunori Kataoka Core-shell microsphere and its production
JP2007099929A (en) * 2005-10-05 2007-04-19 Dainippon Ink & Chem Inc Hydrophilic colloidal particle and method for producing the same
CN101245120A (en) * 2008-03-17 2008-08-20 烟台大学 Process for producing cross-linked polymer microsphere with even grain diameter
CN115368518A (en) * 2022-07-15 2022-11-22 西南石油大学 Colloidal particle emulsifier and preparation method and application thereof
CN116063641A (en) * 2023-02-08 2023-05-05 深圳好电科技有限公司 Flame-retardant lithium battery anode adhesive and preparation method thereof
CN116463086A (en) * 2023-04-27 2023-07-21 衡水中裕铁信防水技术有限公司 Microcapsule slow-release self-adhesive and slow-release self-adhesive waterproof coiled material

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