丙烯酸酯压敏胶、定向聚苯乙烯膨胀胶带及其制备方法与应用

Acrylate pressure-sensitive adhesive, oriented polystyrene expansion adhesive tape, and preparation method and application thereof

文档序号：3009 发布日期：2021-09-17 浏览：63次中文

1. The acrylate pressure-sensitive adhesive is characterized in that the preparation monomer comprises the following components in percentage by mass:

20 to 90 percent of acrylate soft monomer;

5 to 80 percent of acrylate hard monomer;

1 to 18 percent of crosslinking monomer; and

0.1 to 3 percent of functional monomer;

wherein the functional monomer is selected from at least one of 3 (ethoxy) bisphenol A dimethacrylate, 2 (ethoxy) bisphenol A dimethacrylate and 4 (ethoxy) bisphenol A dimethacrylate; the glass transition temperature of the acrylate pressure-sensitive adhesive is-40 ℃ to-30 ℃.

2. The acrylate pressure-sensitive adhesive of claim 1, wherein the soft acrylate monomer is at least one selected from the group consisting of butyl acrylate, isooctyl acrylate, ethyl acrylate, and lauryl acrylate.

3. The acrylate pressure sensitive adhesive of claim 1, wherein the acrylate hard monomer is selected from at least one of methyl acrylate, vinyl acetate, styrene, and methyl methacrylate.

4. The acrylate pressure-sensitive adhesive of claim 1, wherein the crosslinking monomer is at least one selected from the group consisting of acrylic acid, methacrylic acid, maleic acid, hydroxyethyl acrylate and hydroxypropyl acrylate.

5. The acrylate pressure-sensitive adhesive according to any one of claims 1 to 4, wherein in the preparation monomers, the mass content of the acrylate soft monomer is 70-75%, the mass content of the acrylate hard monomer is 18-25%, the mass content of the crosslinking monomer is 4-7%, and the mass content of the functional monomer is 0.5-3%.

6. The acrylate pressure-sensitive adhesive according to any one of claims 1 to 4, characterized in that the raw materials for preparing the acrylate pressure-sensitive adhesive comprise an initiator and a solvent, wherein the mass content of the preparation monomer is 28 to 45 percent, the mass content of the initiator is 0.1 to 2 percent, and the mass content of the solvent is 60 to 70 percent.

7. The preparation method of the acrylate pressure-sensitive adhesive is characterized by comprising the following steps:

and mixing the prepared monomer, the initiator and the solvent, and carrying out reflux reaction to obtain the acrylate pressure-sensitive adhesive.

8. Use of the acrylate pressure sensitive adhesive according to any of claims 1 to 6 for the preparation of pressure sensitive adhesive articles.

9. A pressure-sensitive adhesive composition comprising the acrylate pressure-sensitive adhesive according to any one of claims 1 to 6 and a curing agent.

10. An oriented polystyrene expanded tape, which comprises an oriented polystyrene film and a pressure-sensitive adhesive layer provided on the oriented polystyrene film, wherein the pressure-sensitive adhesive layer is prepared from the pressure-sensitive adhesive composition according to claim 10.

11. A battery comprising the oriented polystyrene intumescent tape of claim 10.

Background

With the rapid development of the lithium battery industry, various new materials have appeared around the lithium battery industry. The oriented polystyrene expansion adhesive tape is also an important material, and is prepared by coating an oriented and stretched polystyrene film with special acrylate pressure-sensitive adhesive. The oriented polystyrene expansion adhesive tape is mainly used for winding the battery cell of the batteries such as polymer lithium batteries and the like, and can solve the problem of a gap between the battery cell and the shell due to the expansion function. The oriented polystyrene expanded adhesive tape on the market at present basically adopts acrylate pressure-sensitive adhesive used for common adhesive tapes, and cannot meet the use environment of electrolyte resistance, so that the problems of unstable viscosity, degumming, falling off and the like easily occur, and the stable operation of a battery is not facilitated.

Disclosure of Invention

Based on the above, it is necessary to provide an acrylate pressure sensitive adhesive and an oriented polystyrene expanded tape with good chemical resistance, and a preparation method and applications thereof.

The invention provides an acrylate pressure-sensitive adhesive, which comprises the following preparation monomers in percentage by mass:

In some of these embodiments, the soft acrylate monomer is selected from at least one of butyl acrylate, isooctyl acrylate, ethyl acrylate, and lauryl acrylate.

In some of these embodiments, the acrylate hard monomer is selected from at least one of methyl acrylate, vinyl acetate, styrene, and methyl methacrylate.

In some of these embodiments, the crosslinking monomer is selected from at least one of acrylic acid, methacrylic acid, maleic acid, hydroxyethyl acrylate, and hydroxypropyl acrylate.

In some embodiments, in the preparation monomers, the mass content of the acrylate soft monomer is 70% to 75%, the mass content of the acrylate hard monomer is 18% to 25%, the mass content of the crosslinking monomer is 4% to 7%, and the mass content of the functional monomer is 0.5% to 3%.

In some embodiments, in addition to the preparation monomer, the preparation raw material of the acrylate pressure-sensitive adhesive further includes an initiator and a solvent, and the preparation monomer is 28 to 45% by mass, the initiator is 0.1 to 2% by mass, and the solvent is 60 to 70% by mass.

In another aspect of the present invention, a preparation method of an acrylate pressure-sensitive adhesive is provided, which comprises the following steps:

and mixing the prepared monomer, the initiator and the solvent, and carrying out reflux reaction to obtain the acrylate pressure-sensitive adhesive.

In another aspect of the invention, the application of the acrylate pressure-sensitive adhesive in preparing pressure-sensitive adhesive products is also provided.

In another aspect of the invention, a pressure-sensitive adhesive composition is also provided, which comprises the acrylate pressure-sensitive adhesive and a curing agent.

In another aspect of the present invention, an oriented polystyrene expanded adhesive tape is further provided, which comprises an oriented polystyrene film and a pressure sensitive adhesive layer disposed on the oriented polystyrene film, wherein the pressure sensitive adhesive layer comprises the above pressure sensitive adhesive composition as a raw material.

In another aspect of the present invention, there is also provided a battery comprising the oriented polystyrene expansion tape.

The preparation monomer of the acrylate pressure-sensitive adhesive comprises acrylate soft monomer, acrylate hard monomer, crosslinking monomer and functional monomer with specific content, wherein the functional monomer is at least one selected from 3 (ethoxy) bisphenol A dimethacrylate, 2 (ethoxy) bisphenol A dimethacrylate and 4 (ethoxy) bisphenol A dimethacrylate. The pressure-sensitive adhesive is characterized in that a specific functional monomer containing a bisphenol A group is introduced into the pressure-sensitive adhesive, the pressure-sensitive adhesive has good compatibility with an acrylate prepolymer, the bisphenol A functional group is bonded into a polymer main chain of the acrylate pressure-sensitive adhesive through a polymerization reaction, and the vitrification temperature is controlled between-40 ℃ and-30 ℃, so that the acrylate pressure-sensitive adhesive has excellent chemical resistance, corrosion resistance, heat resistance and weather resistance, and is particularly suitable for oriented polystyrene expansion adhesive tapes. The pressure-sensitive adhesive composition comprises the acrylate pressure-sensitive adhesive and the curing agent, wherein the curing agent is mixed with the acrylate pressure-sensitive adhesive, and the curing agent can perform a crosslinking reaction with a crosslinking active group in the acrylate pressure-sensitive adhesive, so that good bonding performance is achieved. The oriented polystyrene expansion adhesive tape containing the acrylate pressure-sensitive adhesive is applied to cell packaging of batteries, for example, the oriented polystyrene expansion adhesive tape is used for winding cells of batteries such as polymer lithium batteries, is not easy to degum when being contacted with electrolyte for a long time, has good chemical resistance, and is beneficial to improving the stability of the batteries.

Detailed Description

In order that the invention may be more fully understood, reference will now be made to the following description. The present invention may be embodied in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

The invention provides acrylate pressure-sensitive adhesive, which comprises the following preparation monomers in percentage by mass:

wherein the functional monomer is at least one selected from 3 (ethoxy) bisphenol A dimethacrylate, 2 (ethoxy) bisphenol A dimethacrylate and 4 (ethoxy) bisphenol A dimethacrylate; the glass transition temperature of the acrylate pressure-sensitive adhesive is-40 ℃ to-30 ℃. It can be understood that the glass transition temperature of the pressure-sensitive adhesive can be controlled to be-40 ℃ to-30 ℃ by adjusting the type and content of the prepared monomer.

The temperature at which a polymer changes from a highly elastic state to a glassy state, which is the transition temperature of an amorphous polymer (including the amorphous portion of a crystalline polymer) from a glassy state to a highly elastic state or from the latter to the former, is the lowest temperature at which the macromolecular segments of the amorphous polymer are free to move, and is generally denoted by Tg. The glass transition temperature Tg is an important parameter for the formulation of the pressure-sensitive adhesive, the pressure-sensitive adhesive is softer at lower Tg, but if the Tg is too low, the cohesive force of the pressure-sensitive adhesive is deteriorated to influence the performance of the pressure-sensitive adhesive, and the pressure-sensitive adhesive needs higher cohesive force, so that a balance point needs to be reached.

In addition, by regulating the proportion of the acrylate soft monomer, the acrylate hard monomer and the crosslinking monomer in the preparation monomer, the acrylate pressure-sensitive adhesive with different viscosity, mechanical strength and adhesive force can be prepared so as to adapt to different application scenes.

The acrylate soft monomer can provide good viscosity for acrylate pressure sensitive adhesives. In some of these embodiments, the soft acrylate monomer is selected from at least one of butyl acrylate, isooctyl acrylate, ethyl acrylate, and lauryl acrylate.

The acrylate hard monomer can provide cohesion to the acrylate pressure sensitive adhesive. The cohesive force refers to the capability of the pressure-sensitive adhesive colloid to resist the damage caused by external force. In some of these embodiments, the acrylate hard monomer is selected from at least one of methyl acrylate, vinyl acetate, styrene, and methyl methacrylate. Further, the acrylate hard monomer is styrene. The obtained acrylate pressure-sensitive adhesive has relatively high rigidity, can be used for preparing the oriented polystyrene expanded adhesive tape, has better adhesive force with a polystyrene base material, and is not easy to degum.

The crosslinking monomer can provide a group with crosslinking activity for the acrylate pressure-sensitive adhesive. In some of these embodiments, the crosslinking monomer is selected from at least one of acrylic acid, methacrylic acid, maleic acid, hydroxyethyl acrylate, and hydroxypropyl acrylate. The carboxyl or hydroxyl in the crosslinking monomer has good reactivity and can react and crosslink with the curing agent, so that the acrylate pressure-sensitive adhesive is cured, and the bonding property of the acrylate pressure-sensitive adhesive is further improved.

In some embodiments, in the preparation monomers, the mass content of the acrylate soft monomer is 70-75%, the mass content of the acrylate hard monomer is 18-25%, the mass content of the crosslinking monomer is 4-7%, and the mass content of the functional monomer is 0.5-3%.

In some of these embodiments, the mass content of the acrylate soft monomer in the preparation monomers is 70%, 71%, 72%, 73%, 74%, or 75%; the mass content of the acrylate hard monomer is 18%, 19%, 20%, 21%, 22% or 23%; the mass content of the crosslinking monomer is 4%, 4.5%, 5%, 5.5%, 6%, 6.5% or 7%; the mass of the functional monomer is 0.5%, 0.6%, 0.8%, 1%, 1.2%, 1.5%, 1.7%, 2%, 2.2%, 2.4%, 2.5%, 2.7%, 2.8%, or 3%.

In some embodiments, in addition to the preparation of the monomer, the raw materials for preparing the acrylate pressure-sensitive adhesive further include an initiator and a solvent, and the mass content of the preparation monomer is 28-45%, the mass content of the initiator is 0.1-2%, and the mass content of the solvent is 60-70%.

In some of these embodiments, the initiator is benzoyl peroxide or azobisisobutyronitrile. The initiator functions to provide the desired free radicals for the polymerization reaction to produce the monomer.

In some of these embodiments, the solvent is ethyl acetate or toluene. Preferably, the solvent is ethyl acetate. The cost is lower by using ethyl acetate as a solvent, and the cost performance is high.

The invention also provides a preparation method of the acrylate pressure-sensitive adhesive, which comprises the following steps:

mixing the prepared monomer, the initiator and the solvent, and carrying out reflux reaction to obtain the acrylate pressure-sensitive adhesive.

In some embodiments, the preparation monomer, the initiator and the solvent are mixed, and the step of refluxing comprises:

mixing a prepared monomer, part of initiator and part of solvent to obtain a pre-polymerized monomer;

carrying out reflux reaction on part of the pre-polymerized monomer and the other part of the solvent under the protection of inert gas;

adding the residual prepolymer monomer, the residual initiator and the residual solvent, and continuing reflux reaction.

The preparation method of the acrylate pressure-sensitive adhesive has the advantages of stable reaction and easy control, and the obtained acrylate pressure-sensitive adhesive has good performance.

In some of these embodiments, the temperature of the reflux reaction is from 78 ℃ to 80 ℃.

In some examples, the acrylate pressure sensitive adhesive is prepared according to the following steps S1-S7:

step S1: weighing the components according to the formula;

step S2: introducing nitrogen into the reaction kettle to exhaust air, adding 80% of solvent into the reaction kettle, and heating to 78-80 ℃ for reflux;

step S3: adding the prepared monomer into a feeding kettle, dissolving 80% of initiator by using 10% of solvent, adding into the feeding kettle, and uniformly stirring to obtain a mixed pre-polymerization monomer;

step S4: adding 20% of mixed prepolymer monomer into a reaction kettle, and reacting for 40 minutes at 78-80 ℃ under the condition of heat preservation;

step S5: and dropwise adding the remaining 80% of the mixed prepolymer monomer into the reaction kettle, keeping the temperature at 78-80 ℃, and finishing dropwise adding within 3-3.5 hours.

Step S6: dissolving the rest 20% of the initiator by using the rest 10% of the solvent, then dropwise adding the initiator into the reaction kettle, and keeping the temperature for reacting for 2 hours after the dropwise adding is finished;

step S7: and after the reaction is finished, cooling to below 40 ℃ to obtain the acrylate pressure-sensitive adhesive.

The invention also provides application of the acrylate pressure-sensitive adhesive in preparing pressure-sensitive adhesive products.

The invention also provides a pressure-sensitive adhesive composition which comprises the acrylate pressure-sensitive adhesive and a curing agent. The curing agent is mixed with the acrylate pressure-sensitive adhesive, and the curing agent can perform crosslinking reaction with crosslinking active groups in the acrylate pressure-sensitive adhesive, so that good bonding performance is achieved.

Specifically, in the pressure-sensitive adhesive composition, the acrylate pressure-sensitive adhesive and the curing agent may be in a separately packaged state, for example, an AB adhesive, the acrylate pressure-sensitive adhesive and the curing agent being the a-component and the B-component, respectively. Mixing the component A and the component B when in use; or may be mixed with each other to form a pressure-sensitive adhesive coating liquid. The proportion of the acrylate pressure sensitive adhesive and the curing agent can be adjusted according to actual use requirements.

In some of these embodiments, the curing agent is hexamethylene diisocyanate.

The invention also provides an oriented polystyrene expanded adhesive tape, which comprises an oriented polystyrene film and a pressure-sensitive adhesive layer arranged on the oriented polystyrene film, wherein the pressure-sensitive adhesive layer is prepared from the pressure-sensitive adhesive composition. The oriented polystyrene expansion adhesive tape containing the acrylate pressure-sensitive adhesive has good chemical resistance, is not easy to degum after being contacted with electrolyte for a long time, and is applied to battery cell packaging to help to improve the stability of a battery.

In some embodiments, in the oriented polystyrene expanded adhesive tape, the mass ratio of the acrylate pressure-sensitive adhesive to the curing agent is 100: (2-4). In some embodiments, the mass ratio of the acrylate pressure-sensitive adhesive to the curing agent is 100: 3.5.

in some of these examples, the oriented polystyrene intumescent tape was prepared by the following steps:

uniformly mixing acrylate pressure-sensitive adhesive and a curing agent to obtain pressure-sensitive adhesive coating liquid;

the pressure-sensitive adhesive coating liquid was coated on a double-sided release film and then transferred to an oriented polystyrene film.

The invention also provides a battery, which comprises the oriented polystyrene expansion adhesive tape. In some embodiments, the oriented polystyrene expansion tape is used to wrap around the cell of a battery, and may fill the gap between the cell and the casing.

The following are specific examples.

Example 1:

1. a pressure-sensitive adhesive for oriented polystyrene expansion tape was prepared, the glass transition temperature Tg of the formulation of this example was-33.3 ℃, and the components were weighed according to the formulation shown in table 1:

table 1 acrylate pressure sensitive adhesive composition formulation of example 1

The acrylate pressure-sensitive adhesive of the present example was prepared as follows:

1) weighing the components according to the formula in the table 1;

2) introducing nitrogen into the reaction kettle to exhaust air, adding 80% of solvent into the reaction kettle, and heating to 78-80 ℃ for reflux;

3) adding the prepared monomer into a feeding kettle, dissolving 80% of initiator by using 10% of solvent, adding into the feeding kettle, and uniformly stirring to obtain a mixed pre-polymerization monomer;

4) adding 20% of mixed prepolymer monomer into a reaction kettle, and reacting for 40 minutes at 78-80 ℃ under the condition of heat preservation;

5) and dropwise adding the remaining 80 percent of the mixed prepolymer monomer into the reaction kettle, keeping the temperature at 78-80 ℃, and finishing dropwise adding within 3-3.5 hours.

6) Dissolving the rest 20% of the initiator by using the rest 10% of the solvent, then dropwise adding the initiator into the reaction kettle, and keeping the temperature for reacting for 2 hours after the dropwise adding is finished;

7) after the reaction is finished, the temperature is reduced to be below 40 ℃, and the acrylate pressure-sensitive adhesive of the embodiment is prepared.

2. Preparation of oriented polystyrene expanded adhesive tape

Weighing the components according to the following formula: 10kg of the prepared acrylate pressure-sensitive adhesive and 350g of curing agent hexamethylene diisocyanate.

Adding acrylate pressure-sensitive adhesive into 5kg of ethyl acetate for dilution, then adding hexamethylene diisocyanate, and uniformly stirring to obtain a pressure-sensitive adhesive coating liquid; firstly, coating acrylate pressure-sensitive adhesive on a double-sided release film by using a coating machine, and then transferring the acrylate pressure-sensitive adhesive to an oriented polystyrene film by using a rewinding machine to obtain the oriented polystyrene expanded adhesive tape.

Example 2:

1. a pressure-sensitive adhesive for oriented polystyrene expansion tape was prepared, the glass transition temperature Tg of the formulation of this example was-36.3 ℃, and the components were weighed according to the formulation shown in table 2:

table 2 acrylate pressure sensitive adhesive composition formulation of example 2

The acrylate pressure-sensitive adhesive of the present example was prepared as follows:

1) weighing the components according to the formula in the table 2;

2) introducing nitrogen into the reaction kettle to exhaust air, adding 80% of solvent into the reaction kettle, and heating to 78-80 ℃ for reflux;

4) adding 20% of mixed prepolymer monomer into a reaction kettle, and reacting for 40 minutes at 78-80 ℃ under the condition of heat preservation;

5) and dropwise adding the remaining 80 percent of the mixed prepolymer monomer into the reaction kettle, keeping the temperature at 78-80 ℃, and finishing dropwise adding within 3-3.5 hours.

7) after the reaction is finished, the temperature is reduced to be below 40 ℃, and the acrylate pressure-sensitive adhesive of the embodiment is prepared.

2. Preparation of oriented polystyrene expanded adhesive tape

Weighing the components according to the following formula: 10kg of the prepared acrylate pressure-sensitive adhesive and 350g of curing agent hexamethylene diisocyanate.

Example 3:

1. a pressure-sensitive adhesive for oriented polystyrene expansion tape was prepared, the glass transition temperature Tg of the formulation of this example was-38.3 ℃, and the components were weighed according to the formulation shown in table 1:

table 3 acrylate pressure sensitive adhesive composition formulation of example 3

The acrylate pressure-sensitive adhesive of the present example was prepared as follows:

1) weighing the components according to the formula in the table 3;

2) introducing nitrogen into the reaction kettle to exhaust air, adding 80% of solvent into the reaction kettle, and heating to 78-80 ℃ for reflux;

4) adding 20% of mixed prepolymer monomer into a reaction kettle, and reacting for 40 minutes at 78-80 ℃ under the condition of heat preservation;

5) and dropwise adding the remaining 80 percent of the mixed prepolymer monomer into the reaction kettle, keeping the temperature at 78-80 ℃, and finishing dropwise adding within 3-3.5 hours.

7) after the reaction is finished, the temperature is reduced to be below 40 ℃, and the acrylate pressure-sensitive adhesive of the embodiment is prepared.

2. Preparation of oriented polystyrene expanded adhesive tape

Weighing the components according to the following formula: 10kg of the prepared acrylate pressure-sensitive adhesive and 350g of curing agent hexamethylene diisocyanate.

Comparative example 1:

essentially the same as in example 1, except for the substitution of other kinds of functional monomers. The formulation of the acrylate pressure sensitive adhesive composition of comparative example 1 is shown in table 4.

Table 4 formula of acrylate pressure sensitive adhesive composition of comparative example 1

Comparative example 2:

essentially the same as in example 2, except for the substitution of other kinds of functional monomers. The formulation of the acrylate pressure sensitive adhesive composition of comparative example 2 is shown in table 5.

TABLE 5 formulation of acrylate pressure sensitive adhesive composition of comparative example 2

Comparative example 3:

essentially the same as in example 3, except for the substitution of other kinds of functional monomers. The formulation of the acrylate pressure sensitive adhesive composition of comparative example 3 is shown in Table 6.

TABLE 6 formulation of acrylate pressure sensitive adhesive composition of comparative example 3

Performance testing

The oriented polystyrene expansion tapes prepared in the above examples and comparative examples were respectively attached to aluminum foils, immersed in an electrolyte, and placed in an oven for a temperature resistance test at 85 ℃ for 24 hours. If degumming occurs at the specified time and temperature, the product is unqualified; and if no degumming occurs, the product is qualified.

TABLE 7 oriented polystyrene intumescent tape test results

Sample (I)	Degumming was tested at 85 ℃ for 24 hours	Results of the experiment
			Example 1	Non-degumming	Qualified
Example 2	Non-degumming	Qualified
			Example 3	Non-degumming	Qualified
Comparative example 1	Degumming	Fail to be qualified
			Comparative example 2	Degumming	Fail to be qualified
Comparative example 3	Degumming	Fail to be qualified

Referring to the test results in table 7, the oriented polystyrene expanded tapes prepared in examples 1 to 3 have excellent chemical resistance and electrolyte resistance compared to the oriented polystyrene expanded tapes prepared in comparative examples 1 to 3, and can be used in a lithium battery environment for a long time without degumming.

The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

The above-mentioned embodiments only express several embodiments of the present invention, so as to understand the technical solutions of the present invention specifically and in detail, but not to be understood as the limitation of the protection scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. It should be understood that the technical solutions provided by the present invention, which are obtained by logical analysis, reasoning or limited experiments, are within the scope of the present invention as set forth in the appended claims. Therefore, the protection scope of the patent of the invention is subject to the content of the appended claims, and the description can be used for explaining the content of the claims.

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