A heat-resistant electrolyte hot melt tape and its preparation method and application

Abstract

The present invention provides an electrolyte-resistant hot melt tape, which comprises a PET substrate and a rubber hot melt adhesive layer coated on its surface. The rubber hot melt adhesive layer comprises the following components in parts by weight: 60-160 parts of styrene-butadiene rubber, 10-40 parts of maleic anhydride-modified polyolefin, 1-5 parts of epoxy curing agent, 10-40 parts of hydroxyl-terminated liquid polybutadiene, 1-5 parts of polyisocyanate curing agent, and 20-60 parts of rosin tackifying resin. The rubber hot melt adhesive layer of the electrolyte-resistant hot melt tape is tightly compounded with the polar PET substrate. At the same time, the moderate cross-linking between the components of the rubber hot melt adhesive layer can reduce the infiltration of the electrolyte, so that the electrolyte-resistant hot melt tape has excellent bonding strength before and after being immersed in the electrolyte, does not bubble or delaminate, improves the passing rate of the battery drop test, meets the requirements of the lithium battery industry for tape products, and improves the battery safety factor.

Description

Technical Field

[0001] The present invention relates to a tape, and more specifically, to an electrolyte-resistant hot melt tape and its preparation method and application. Technical Background

[0002] Lithium-ion batteries are a type of battery with lithium metal or lithium alloy as the positive / negative electrode material and using a non-aqueous electrolyte solution. They are widely used in electronic devices such as mobile phones, cars, and laptops. Various tapes are used inside lithium battery cells to improve the safety and stability of the battery. These tapes need to be soaked in high-temperature electrolyte for a long time, so they must have excellent electrolyte resistance and stable bonding performance, and there should be no peeling or bubbling phenomenon.

[0003] The tape coating substrates currently used in lithium batteries need to have a series of requirements such as water, oil, and solvent resistance, excellent impact resistance, good electrical performance, and good dimensional performance. PET film is the substrate widely used in current lithium battery tapes. However, the hot melt adhesives based on traditional rubber materials such as styrene-butadiene rubber and polyolefin have poor adhesion on polar substrates such as PET. Especially after the tapes made of this kind of hot melt adhesive are soaked in electrolyte, their adhesion becomes even worse, and there are obvious cases of liquid leakage and degumming, or even the entire surface detaching from the PET substrate.

[0004] Therefore, there is a need for a hot melt tape with a modified rubber hot melt adhesive layer that has good adhesion on polar substrates such as PET and good electrolyte resistance performance. Summary of the Invention

[0005] Aiming at the defects of the existing hot melt tapes that the rubber hot melt adhesive layer has poor adhesion on PET substrates and is prone to detachment, an object of one aspect of the present invention is to provide an electrolyte-resistant hot melt tape, which includes a PET substrate and a rubber hot melt adhesive layer coated on its surface. The rubber hot melt adhesive layer includes the following components in parts by weight:

[0006]

[0007] More preferably, the rubber hot melt adhesive layer includes the following components in parts by weight:

[0008]

[0009] Preferably, the Mooney viscosity of the styrene-butadiene rubber is 40 - 80.

[0010] Preferably, the content of styrene in the styrene-butadiene rubber is 15% - 30%.

[0011] Preferably, the weight average molecular weight of the maleic anhydride-modified polyolefin is 10000 - 30000.

[0012] Preferably, the acid value of the maleic anhydride modified polyolefin is 20 to 40.

[0013] Preferably, the maleic anhydride content in the maleic anhydride modified polyolefin is 1.5 to 3 wt%.

[0014] Preferably, the functionality of the epoxy curing agent is 2 to 5.

[0015] Preferably, the epoxy curing agent is selected from one or more of metaxylylenediamine epoxide, 4,4-diaminodiphenylmethane epoxy resin, and triglycidyl p-aminophenol.

[0016] Preferably, the weight average molecular weight of the hydroxyl-terminated liquid polybutadiene is 3000 to 8000.

[0017] Preferably, the hydroxyl value of the hydroxyl-terminated liquid polybutadiene is 0.5 to 1.5.

[0018] Preferably, the functionality of the polyisocyanate curing agent is 1 to 3.

[0019] Preferably, the polyisocyanate curing agent is selected from one or more of hexamethylene diisocyanate, isophorone diisocyanate, and diphenylmethane diisocyanate.

[0020] Preferably, the softening point of the rosin tackifying resin is 90 to 130 °C.

[0021] Preferably, the rosin tackifying resin is selected from one or more of pentaerythritol rosin tackifying resin, rosin glyceride, and disproportionated rosin.

[0022] Another object of the present invention is to provide a method for preparing the above-mentioned electrolyte-resistant hot melt tape, the preparation method comprising the following steps:

[0023] (1) Add the maleic anhydride modified polyolefin to a solvent to obtain solution A;

[0024] (2) Add styrene-butadiene rubber, hydroxyl-terminated liquid polybutadiene, and rosin tackifying resin to the solution A in sequence to obtain a mixed liquid B;

[0025] (3) Add the epoxy curing agent and the isocyanate curing agent to the mixed liquid B to obtain a rubber hot melt adhesive composition; and

[0026] (4) Uniformly coat the electrolyte-resistant resin composition on the PET substrate, dry, and cure to obtain the electrolyte-resistant hot melt tape.

[0027] Preferably, in step (1), the solvent is selected from one or more of benzene, xylene, and methyl ethyl ketone.

[0028] Preferably, in step (1), the addition amount of the solvent is 500 to 1500 parts by weight.

[0029] Preferably, in step (1), after adding the maleic anhydride-modified polyolefin into the solvent, it is stirred at a temperature of 70 to 120 °C until a clear solution is formed, thus obtaining solution A.

[0030] Preferably, in step (2), styrene-butadiene rubber, hydroxyl-terminated liquid polybutadiene, and rosin tackifying resin are sequentially added into the solution A, and stirred evenly at a temperature of 40 to 80 °C, thus obtaining mixture B.

[0031] Preferably, in step (3), an epoxy curing agent and an isocyanate curing agent are added into the mixture B and stirred evenly at room temperature, thus obtaining a curable rubber adhesive.

[0032] Preferably, the temperature for the above drying is 80 to 120 °C.

[0033] Preferably, the temperature for the above curing is 40 to 80 °C, and the curing time is 2 to 4 days.

[0034] Another object of the present invention is to provide an application of the electrolyte-resistant hot melt tape in a lithium-ion battery. Specific Embodiments

[0035] Aiming at the problem that the hot melt adhesive layer of the tape used in lithium batteries in the prior art has poor adhesion on polar substrates such as PET, the inventors of the present application have conducted in-depth research and found for the first time that on the basis of using maleic anhydride and hydroxyl-modified polymers, providing a suitable crosslinking degree at the same time can solve this problem. On this basis, the present invention has been completed.

[0036] The electrolyte-resistant hot melt tape of the present invention includes a PET substrate and a rubber hot melt adhesive layer coated on its surface. The rubber hot melt adhesive layer includes the following components in parts by weight: 50 to 160 parts of styrene-butadiene rubber, 10 to 40 parts of maleic anhydride-modified polyolefin, 0.5 to 4 parts of epoxy curing agent, 10 to 40 parts of hydroxyl-terminated liquid polybutadiene, 0.5 to 5 parts of polyisocyanate curing agent, and 20 to 60 parts of rosin tackifying resin.

[0037] In some specific embodiments of the present invention, the electrolyte-resistant hot melt tape of the present invention includes a PET substrate and a rubber hot melt adhesive layer coated on its surface. The rubber hot melt adhesive layer includes the following components in parts by weight: 60 to 120 parts of styrene-butadiene rubber, 15 to 35 parts of maleic anhydride-modified polyolefin, 1 to 3 parts of epoxy curing agent, 25 to 50 parts of hydroxyl-terminated liquid polybutadiene, 1 to 3 parts of polyisocyanate curing agent, and 25 to 50 parts of rosin tackifying resin.

[0038] In a specific embodiment of the present invention, the rubber hot melt adhesive layer comprises the following components in parts by weight: 70 parts of styrene-butadiene rubber, 20 parts of maleic anhydride-modified polyolefin, 1 part of epoxy curing agent, 30 parts of hydroxyl-terminated liquid polybutadiene, 2 parts of polyisocyanate curing agent, and 30 parts of rosin tackifying resin. The Mooney viscosity of the styrene-butadiene rubber is 60-70, and the content of styrene is 21%-24%. The weight-average molecular weight of the maleic anhydride-modified polyolefin is 25,000-30,000, the acid value is 25-28, and the maleic anhydride content is 1.5%-1.8%. The weight-average molecular weight of the hydroxyl-terminated liquid polybutadiene is 5,000-7,000, and the hydroxyl value is 0.54-0.64. The polyisocyanate curing agent is hexamethylene diisocyanate. The epoxy curing agent is m-phenylenediamine epoxide. The rosin tackifying resin is pentaerythritol rosin tackifying resin with a softening point of 100 °C.

[0039] In a specific embodiment of the present invention, the rubber hot melt adhesive layer comprises the following components in parts by weight: 90 parts of styrene-butadiene rubber, 30 parts of maleic anhydride-modified polyolefin, 1.5 parts of epoxy curing agent, 20 parts of hydroxyl-terminated liquid polybutadiene, 1.5 parts of polyisocyanate curing agent, and 40 parts of rosin tackifying resin. The Mooney viscosity of the styrene-butadiene rubber is 70-80, and the content of styrene is 18%-21%. The weight-average molecular weight of the maleic anhydride-modified polyolefin is 15,000-20,000, the acid value is 30-33, and the maleic anhydride content is 1.5%-1.8%. The weight-average molecular weight of the hydroxyl-terminated liquid polybutadiene is 4,000-6,000, and the hydroxyl value is 0.64-0.72. The polyisocyanate curing agent is toluene diisocyanate. The rosin tackifying resin is rosin glyceride with a softening point of 90 °C.

[0040] In a specific embodiment of the present invention, the rubber hot melt adhesive layer comprises the following components in parts by weight: 110 parts of styrene-butadiene rubber, 25 parts of maleic anhydride-modified polyolefin, 1.5 parts of epoxy curing agent, 25 parts of hydroxyl-terminated liquid polybutadiene, 1.5 parts of polyisocyanate curing agent, and 35 parts of rosin tackifying resin. The Mooney viscosity of the styrene-butadiene rubber is 50-60, and the content of styrene is 24%-27%. The weight-average molecular weight of the maleic anhydride-modified polyolefin is 20,000-25,000, the acid value is 28-31, and the maleic anhydride content is 1.5%-1.8%. The weight-average molecular weight of the hydroxyl-terminated liquid polybutadiene is 6,000-8,000, and the hydroxyl value is 0.72-0.80. The polyisocyanate curing agent is a compound of hexamethylene diisocyanate and toluene diisocyanate in a mass ratio of 1:0.5. The epoxy curing agent is a compound of 4,4-diaminodiphenylmethane epoxy resin and m-phenylenediamine epoxide in a mass ratio of 1:0.5. The rosin tackifying resin is a compound of pentaerythritol rosin tackifying resin and rosin glyceride in a mass ratio of 20:15.

[0041] In the electrolyte-resistant resin composition of the present invention, styrene-butadiene rubber has good airtightness and chemical corrosion resistance, and is suitable as the main resin of the electrolyte-resistant glue. In some more preferred embodiments of the present invention, the weight part content of styrene-butadiene rubber is 80 to 110 parts. In some preferred embodiments of the present invention, the content of styrene in styrene-butadiene rubber is 15% to 30%. Within this range, the molecular weight is moderate, and the ratio of the hard and soft segments is moderate, meeting the requirements of electrolyte resistance and tape coating process.

[0042] In the electrolyte-resistant resin composition of the present invention, the function of maleic anhydride-modified polyolefin is to provide high PET adhesion and electrolyte resistance. In some more preferred embodiments of the present invention, the weight part content of maleic anhydride-modified polyolefin is 20 to 30 parts.

[0043] In the electrolyte-resistant resin composition of the present invention, polyisocyanate curing agent and epoxy curing agent form a compound. This curing agent can react with hydroxyl groups to achieve the crosslinking density of the adhesive layer and reduce the infiltration of electrolyte. The function of the epoxy curing agent is that it can react with carboxyl groups to achieve the crosslinking density of the adhesive layer and reduce the infiltration of electrolyte. The epoxy curing agents that can be used in the present invention include but are not limited to metaxylylenediamine epoxide, 4,4-diaminodiphenylmethane epoxy resin, and triglycidyl p-aminophenol. In some more preferred embodiments of the present invention, the weight part content of the epoxy curing agent is 1 to 2.5 parts.

[0044] In the electrolyte-resistant resin composition of the present invention, the function of the polyisocyanate curing agent is to react with hydroxyl groups to achieve the crosslinking density of the adhesive layer and reduce the infiltration of electrolyte. The polyisocyanate curing agents that can be used in the present invention include but are not limited to hexamethylene diisocyanate, isophorone diisocyanate, and diphenylmethane diisocyanate. In some more preferred embodiments of the present invention, the weight part content of the polyisocyanate curing agent is 1 to 3 parts.

[0045] In the electrolyte-resistant resin composition of the present invention, the function of hydroxyl-terminated liquid polybutadiene is to provide crosslinkable non-polar crosslinking segments and further improve the electrolyte resistance. In some more preferred embodiments of the present invention, the weight part content of hydroxyl-terminated liquid polybutadiene is 20 to 30 parts.

[0046] In the electrolyte-resistant resin composition of the present invention, the rosin tackifying resin can adjust the initial adhesion of the rubber hot melt adhesive layer to reach the required adhesion. If the softening point of the rosin tackifying resin is moderate, the tackifying effect can be achieved. In combination with other raw materials, the PET substrate rubber hot melt tape prepared using the electrolyte-resistant resin composition of the present invention can meet the initial peel force requirements. The rosin tackifying resins used in the present invention include, but are not limited to, pentaerythritol rosin tackifying resin, rosin glyceride, disproportionated rosin, or combinations thereof. In some more preferred embodiments of the present invention, the weight part content of the rosin tackifying resin is 25 to 40 parts.

[0047] In the electrolyte-resistant resin composition of the present invention, maleic anhydride-modified polyolefin and hydroxyl-terminated liquid polybutadiene contain strong polar groups, which can enhance the overall polarity of the resin, increase the adhesion of the film formed by the composition to PET or other adherends. At the same time, these groups can react to form a network structure, which can effectively prevent the penetration of electrolytes. Based on this principle, in the electrolyte-resistant resin composition provided by the present invention, styrene-butadiene rubber is used as the main resin, and maleic anhydride-modified polyolefin, hydroxyl-terminated liquid polybutadiene, and a curing agent are introduced. Through heat curing, a special cross-linked system is formed. The special functional group maleic anhydride group contained therein forms hydrogen bond adhesion by enhancing the resin polarity, improving the adhesion effect of the resin on the substrate. At the same time, an appropriate degree of cross-linking can effectively reduce the penetration of electrolytes. By adjusting the addition amount of the cross-linkable resin and the content of the curing agent, the above resin composition can have high electrolyte resistance performance, and at the same time, it has excellent processability on the PET substrate. At the same time, by adding rosin tackifying resin, the expected initial tack of the tape is achieved.

[0048] The preparation method of the electrolyte-resistant hot melt tape of the present invention includes the following steps:

[0049] (1) Add maleic anhydride-modified polyolefin to a solvent to obtain solution A;

[0050] (2) Add styrene-butadiene rubber, hydroxyl-terminated liquid polybutadiene, and rosin tackifying resin to the solution A in sequence to obtain mixture B;

[0051] (3) Add epoxy curing agent and isocyanate curing agent to the mixture B to obtain the rubber hot melt adhesive composition; and

[0052] (4) Uniformly coat the electrolyte-resistant resin composition on the PET substrate, dry, and cure to obtain the electrolyte-resistant hot melt tape.

[0053] In the preparation method of the present invention, according to the dissolution rates of the various components of the rubber hot-melt adhesive composition, maleic anhydride-modified polyolefin, styrene-butadiene rubber, hydroxyl-terminated liquid polybutadiene, and rosin tackifying resin are added in sequence. Considering that the maleic anhydride-modified polyolefin has a slow dissolution rate, the maleic anhydride-modified polyolefin is added first, and styrene-butadiene rubber is used to improve the compatibility between the maleic anhydride-modified polyolefin and the hydroxyl-terminated polybutadiene, and a curing agent is used to increase the crosslinking density of the rubber molecules among the various rubber raw materials.

[0054] The above-mentioned organic solvents include but are not limited to toluene, xylene, methyl ethyl ketone, or a combination thereof. The addition amount of the solvent is 500 to 1500 parts by weight. In some preferred embodiments of the present invention, a mixture of the solvents toluene and xylene is used, and the volume ratio of toluene to xylene is preferably 1:0.5 to 1. More preferably, the volume ratio of toluene to xylene is 1:1. In some preferred embodiments of the present invention, in the step (1), the stirring temperature is 80 to 100 °C. In some preferred embodiments of the present invention, in the step (2), the stirring temperature is 60 to 80 °C. In some preferred embodiments of the present invention, in the step (3), the stirring temperature is at room temperature. In some preferred embodiments of the present invention, in the step (4), the drying temperature is 80 to 120 °C, the curing temperature is 40 to 80 °C, and the curing time is 2 to 4 days.

[0055] In step (1), the maleic anhydride-modified polyolefin has a slow dissolution rate, so it is dissolved at a high temperature of 80 to 100 °C. In step (2), the rubber and rosin tackifying resin have low molecular weights, and too high a temperature will cause the solvent to evaporate too quickly. Considering comprehensively, the stirring temperature is controlled at 60 to 80 °C. In this way, each rubber raw material can have a good dissolution rate, and the solvent evaporation rate can be prevented from being too fast, saving energy. In step (4), the rubber hot-melt glue is coated on the corona surface of the PET substrate by a doctor blade or microgravure coater. Its coating process is simple, and existing equipment can be used generally, which is suitable for mass production and has high economic value.

[0056] The beneficial effects of the present invention are as follows: By adjusting the formula of this hot-melt tape and comparing with the performance of existing ordinary tapes, the performance of the hot-melt tape of the present invention is more excellent. The adhesive layer of this formula can be closely compounded with the polar PET substrate, and at the same time, the adhesive layer is moderately crosslinked to reduce the immersion of the electrolyte. It has excellent bonding strength before and after soaking in the electrolyte, does not bubble or delaminate, improves the passing rate of the battery drop test, and meets the core requirements of the lithium battery industry for tape products.

[0057] The following examples further illustrate the above content of the present invention, but it should not be understood that the scope of the above subject matter of the present invention is limited to the above examples. All technologies implemented based on the above content belong to the scope of the present invention.

[0058] In the following examples, the styrene-butadiene rubber used was produced by Jilin Chemical Industry, with the model SBR1502; the maleic anhydride-modified polyolefin used was produced by Toyobo, with the model PMA-KH; the hydroxyl-terminated liquid polybutadiene used was produced by Nippon Soda, with the model NISSO-PB G-2000; the epoxidized metaphenylenediamine used was produced by Mitsubishi of Japan, with the model GA 240; the pentaerythritol rosin tackifying resin used was produced by DTR of France, with the model Dertoline P2L.

[0059] Example 1

[0060] 1.1 The electrolyte-resistant hot melt tape includes a PET substrate and a rubber hot melt adhesive layer coated on its surface. The rubber hot melt adhesive layer includes the following components in parts by weight: 70 parts of styrene-butadiene rubber, 20 parts of maleic anhydride-modified polyolefin, 1 part of epoxy curing agent, 30 parts of hydroxyl-terminated liquid polybutadiene, 2 parts of polyisocyanate curing agent, and 30 parts of rosin tackifying resin.

[0061] The Mooney viscosity of the styrene-butadiene rubber is 60 - 70, and the content of styrene is 21% - 24%. The weight-average molecular weight of the maleic anhydride-modified polyolefin is 25,000 - 30,000, the acid value is 25 - 28, and the maleic anhydride content is 1.5 - 1.8. The weight-average molecular weight of the hydroxyl-terminated liquid polybutadiene is 5,000 - 7,000, and the hydroxyl value is 0.54 - 0.64. The polyisocyanate curing agent is hexamethylene diisocyanate. The epoxy curing agent is epoxidized metaphenylenediamine. The rosin tackifying resin is pentaerythritol rosin tackifying resin, and the softening point is 100°C.

[0062] 1.2 The preparation method of the electrolyte-resistant hot melt tape includes the following steps:

[0063] (1) Add 20 parts by weight of maleic anhydride-modified polyolefin to 300 parts by weight of xylene, and stir evenly at 90°C to dissolve it into a uniform and bright glue to obtain solution A;

[0064] (2) Add 70 parts by weight of styrene-butadiene rubber, 30 parts by weight of hydroxyl-terminated polybutadiene, and 30 parts by weight of rosin tackifying resin to 500 parts by weight of toluene and 200 parts by weight of xylene in sequence, stir evenly at 80°C, and then add the mixed solution A in step (1), and stir evenly at 60°C to obtain mixed solution B;

[0065] (3) Add 1 part by weight of epoxy curing agent and 2 parts by weight of polyisocyanate curing agent to the mixed solution B in step (2), and stir evenly at room temperature to obtain a rubber hot melt adhesive composition;

[0066] (4) Coating the rubber glue prepared in step (3) evenly on the PET substrate through a precision coater to obtain a PET substrate hot melt tape.

[0067] Example 2

[0068] 2.1 The electrolyte-resistant hot melt tape includes a PET substrate and a rubber hot melt adhesive layer coated on its surface, wherein the rubber hot melt adhesive layer includes the following components in parts by weight:

[0069] 90 parts of styrene-butadiene rubber, 30 parts of maleic anhydride-modified polyolefin, 1.5 parts of epoxy curing agent, 20 parts of hydroxyl-terminated liquid polybutadiene, 1.5 parts of polyisocyanate curing agent, and 40 parts of rosin tackifying resin.

[0070] The Mooney viscosity of the styrene-butadiene rubber is 70 - 80, and the content of styrene is 18% - 21%. The weight-average molecular weight of the maleic anhydride-modified polyolefin is 15,000 - 20,000, the acid value is 30 - 33, and the maleic anhydride content is 1.5 - 1.8. The weight-average molecular weight of the hydroxyl-terminated liquid polybutadiene is 4,000 - 6,000, and the hydroxyl value is 0.64 - 0.72. The polyisocyanate curing agent is toluene diisocyanate. The rosin tackifying resin is rosin glyceride, and the softening point is 90°C.

[0071] 2.2 The preparation method of the electrolyte-resistant hot melt tape includes the following steps:

[0072] (1) Add 30 parts by weight of maleic anhydride-modified polyolefin to 300 parts by weight of xylene, and stir evenly at 90°C to dissolve it into a uniform and bright glue to obtain solution A

[0073] (2) Add 90 parts of styrene-butadiene rubber, 20 parts of hydroxyl-terminated polybutadiene, and 40 parts of rosin tackifying resin to 500 parts by weight of toluene and 200 parts by weight of xylene in sequence, stir evenly at 80°C, and then add the mixed solution A in step (1), and stir evenly at 60°C to obtain mixed solution B;

[0074] (3) Add 1.5 parts by weight of epoxy curing agent and 1.5 parts by weight of isocyanate curing agent to the mixed solution B in step (2), and stir evenly at room temperature to obtain a rubber hot melt adhesive composition;

[0075] (4) Coating the rubber glue prepared in step (3) evenly on the PET substrate through a precision coater to obtain an electrolyte-resistant hot melt tape.

[0076] The Mooney viscosity of the styrene-butadiene rubber is 70 - 80, and the content of styrene is 18% - 21%.

[0077] Example 3

[0078] 3.1 Electrolyte-resistant hot melt tape, comprising a PET substrate and a rubber hot melt adhesive layer coated on its surface, wherein the rubber hot melt adhesive layer comprises the following components in parts by weight:

[0079] 110 parts of styrene-butadiene rubber, 25 parts of maleic anhydride-modified polyolefin, 1.5 parts of epoxy curing agent, 25 parts of hydroxyl-terminated liquid polybutadiene, 1.5 parts of polyisocyanate curing agent, 35 parts of rosin tackifying resin.

[0080] The Mooney viscosity of the styrene-butadiene rubber is 50-60, and the content of styrene is 24%-27%. The weight-average molecular weight of the maleic anhydride-modified polyolefin is 20,000-25,000, the acid value is 28-31, and the maleic anhydride content is 1.5-1.8. The weight-average molecular weight of the hydroxyl-terminated liquid polybutadiene is 6,000-8,000, and the hydroxyl value is 0.72-0.80. The polyisocyanate curing agent is a compound of hexamethylene diisocyanate and toluene diisocyanate in a mass ratio of 1:0.5. The epoxy curing agent is a compound of 4,4-diaminodiphenylmethane epoxy resin and m-phenylenediamine epoxide in a mass ratio of 1:0.5. The rosin tackifying resin is a compound of pentaerythritol rosin tackifying resin and glycerol rosinate in a mass ratio of 20:15.

[0081] 3.2 The preparation method of the electrolyte-resistant hot melt tape comprises the following steps:

[0082] (1) Add 25 parts by weight of maleic anhydride-modified polyolefin to 300 parts by weight of xylene, and stir evenly at 90 °C to dissolve it into a uniform and bright glue to obtain solution A;

[0083] (2) Add 110 parts by weight of styrene-butadiene rubber, 25 parts by weight of hydroxyl-terminated polybutadiene, and 35 parts by weight of rosin tackifying resin to 500 parts by weight of toluene and 200 parts by weight of xylene in sequence, stir evenly at 80 °C, and then add the mixed solution A in the step (1), and stir evenly at 60 °C to obtain mixed solution B;

[0084] (3) Add 1.5 parts by weight of epoxy curing agent and 1.5 parts by weight of polyisocyanate curing agent to the mixed solution B in the step (2), and stir evenly at room temperature to obtain a rubber hot melt adhesive composition;

[0085] (4) Coating the rubber glue prepared in the step (3) evenly on the PET substrate by a precision coater to obtain the electrolyte-resistant hot melt tape.

[0086] Comparative Example 1

[0087] 4.1 Electrolyte-resistant hot melt tape, comprising a PET substrate and a rubber hot melt adhesive layer coated on its surface, wherein the rubber hot melt adhesive layer comprises the following components in parts by weight:

[0088] 110 parts of styrene-butadiene rubber, 25 parts of polyolefin, and 35 parts of rosin tackifying resin.

[0089] The Mooney viscosity of the styrene-butadiene rubber is 50-60, and the styrene content is 24%-27%. The weight-average molecular weight of the polyolefin is 20,000-40,000. The rosin tackifying resin is a compound of pentaerythritol rosin tackifying resin and glycerol ester of rosin in a mass ratio of 20:15.

[0090] 4.2 The preparation method of the electrolyte-resistant hot melt tape includes the following steps:

[0091] (1) Add 25 parts by weight of polyolefin to 300 parts by weight of xylene, and stir evenly at 90°C to dissolve it into a uniform and bright glue to obtain solution A;

[0092] (2) Add 110 parts by weight of styrene-butadiene rubber and 35 parts by weight of rosin tackifying resin to 450 parts by weight of toluene and 150 parts by weight of xylene in sequence, stir evenly at 80°C, and then add the mixed solution A in the step (1), and stir evenly at 60°C to obtain mixed solution B;

[0093] (3) Coating the rubber glue prepared in step (2) evenly on the PET substrate through a precision coater to obtain the electrolyte-resistant hot melt tape.

[0094] The following Table 1 shows the performance test results of the electrolyte-resistant hot melt tapes prepared in Examples 1-3 of the present invention:

[0095] Table 1

[0096]

[0097] Note: The test standard for peel strength: GB / T2792-2014

[0098] Electrolyte (LD-88, Dongguan Shanshan Battery Materials Co., Ltd.)

[0099] The above is only the preferred embodiment of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A hot melt adhesive tape resistant to electrolytic solution, comprising a PET substrate and a rubber hot melt adhesive layer coated on its surface, characterized in that, The rubber hot-melt adhesive layer comprises the following components in parts by weight: styrene-butadiene rubber 50 - 160 parts, maleic anhydride-modified polyolefin 10 - 40 parts, epoxy curing agent 0.5 - 4 parts, hydroxyl-terminated liquid polybutadiene 10 - 40 parts, polyisocyanate curing agent 0.5 - 5 parts, rosin tackifying resin 20 - 60 parts; The weight-average molecular weight of the maleic anhydride-modified polyolefin is 10,000 - 30,000, the acid value of the maleic anhydride-modified polyolefin is 20 - 40, and the maleic anhydride content in the maleic anhydride-modified polyolefin is 1.5 - 3 wt%; The functionality of the epoxy curing agent is 2 - 5; The softening point of the rosin tackifying resin is 90 - 130 °C.

2. The electrolyte-resistant hot melt tape according to claim 1, wherein, The rubber hot-melt adhesive layer comprises the following components in parts by weight: styrene-butadiene rubber 60 - 120 parts, maleic anhydride-modified polyolefin 15 - 35 parts, epoxy curing agent 1 - 3 parts, hydroxyl-terminated liquid polybutadiene 15 - 35 parts, polyisocyanate curing agent 1 - 3 parts, rosin tackifying resin 25 - 50 parts.

3. The electrolyte-resistant hot melt adhesive tape according to claim 1, wherein The Mooney viscosity of the styrene-butadiene rubber is 40 - 80, and / or the styrene content in the styrene-butadiene rubber is 15% - 30%.

4. The electrolyte-resistant hot melt tape according to claim 1, characterized in that, The epoxy curing agent is selected from one or more of metaxylylenediamine epoxide, 4,4-diaminodiphenylmethane epoxy resin, and triglycidyl p-aminophenol.

5. The electrolyte-resistant hot melt adhesive tape according to claim 1, characterized in that, The weight-average molecular weight of the hydroxyl-terminated liquid polybutadiene is 3,000 - 8,000, and / or the hydroxyl value of the hydroxyl-terminated liquid polybutadiene is 0.5 - 1.

5.

6. The electrolytic solution resistant hot melt adhesive tape according to claim 1, wherein The functionality of the polyisocyanate curing agent is 1 - 3, and / or the polyisocyanate curing agent is selected from one or more of hexamethylene diisocyanate, isophorone diisocyanate, and diphenylmethane diisocyanate.

7. The electrolyte-resistant hot melt adhesive tape according to claim 1, characterized in that, The rosin tackifying resin is selected from one or more of pentaerythritol rosin tackifying resin, rosin glyceride, and disproportionated rosin.

8. The preparation method of the electrolyte-resistant hot melt adhesive tape according to any one of claims 1-7, characterized in that, The preparation method comprises the following steps: (1) Add the maleic anhydride-modified polyolefin to a solvent to obtain solution A; (2) Add styrene-butadiene rubber, hydroxyl-terminated liquid polybutadiene, and rosin tackifying resin to the solution A in sequence to obtain mixture B; (3) Add the epoxy curing agent and isocyanate curing agent to the mixture B to obtain the rubber hot-melt adhesive composition; (4) Uniformly coat the above rubber hot-melt adhesive composition on the PET substrate, dry, and cure to obtain the electrolyte-resistant hot-melt tape.

9. The preparation method according to claim 8, characterized in that, The preparation method has one or more of the following characteristics: In step (1), the solvent is selected from one or more of benzene, xylene, and methyl ethyl ketone, In step (1), the addition amount of the solvent is 500 - 1500 parts by weight, In step (1), after adding the maleic anhydride-modified polyolefin to the solvent, stir at 70 - 120 °C until a clear solution is formed to obtain solution A, In step (2), add styrene-butadiene rubber, hydroxyl-terminated liquid polybutadiene, and rosin tackifying resin to the solution A in sequence and stir evenly at 40 - 80 °C to obtain mixture B, In step (3), add the epoxy curing agent and polyisocyanate curing agent to the mixture B and stir evenly at room temperature to obtain the rubber hot-melt adhesive composition, In step (4), the drying temperature is 80 to 120 °C. In step (4), the curing temperature is 40 to 80 °C, and the curing time is 2 to 4 days.

10. Application of the electrolyte-resistant hot melt tape according to any one of claims 1-7 in a lithium-ion battery.

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