阅读说明：本技术 一种uv固化聚烯烃热熔胶及其制备方法 (UV-cured polyolefin hot melt adhesive and preparation method thereof ) 是由 何彬 张珂 李有刚 文伟 于 2020-05-14 设计创作，主要内容包括：本发明涉及一种用于电池包装材料粘接的UV固化聚烯烃热熔胶,其原材料由以下组分组成：具有含硅官能团的烯烃类改性聚合物,含异戊二烯单元的聚烯烃弹性体,乙烯-醋酸乙烯酯共聚物,光引发剂和助剂。本发明聚烯烃热熔胶具有低粘度、高初粘力。该聚烯烃热熔胶对施胶温度的要求低于市面上的高粘度聚烯烃热熔胶,在点胶过程中不易出现拉丝现象,且具有极高的初粘力,缩短了保压时间,有助于简化生产工艺、提高生产效率。还具备优异的耐电解液性能。可用于锂离子电池包装材料的粘接,尤其是电池结构的折边粘接。(The invention relates to a UV curing polyolefin hot melt adhesive for bonding a battery packaging material, which comprises the following raw materials: the modified polymer comprises an olefin modified polymer with a silicon-containing functional group, a polyolefin elastomer containing an isoprene unit, an ethylene-vinyl acetate copolymer, a photoinitiator and an auxiliary agent. The polyolefin hot melt adhesive has low viscosity and high initial adhesion. The requirement of the polyolefin hot melt adhesive on the sizing temperature is lower than that of the high-viscosity polyolefin hot melt adhesive on the market, the wire drawing phenomenon is not easy to occur in the sizing process, the initial adhesion is extremely high, the pressure maintaining time is shortened, the production process is facilitated to be simplified, and the production efficiency is improved. And has excellent electrolyte resistance. The adhesive can be used for bonding the packaging material of the lithium ion battery, in particular to the edge folding bonding of the battery structure.)

1. The UV-cured polyolefin hot melt adhesive is characterized in that the raw material of the UV-cured polyolefin hot melt adhesive comprises the following components: the modified polymer comprises an olefin modified polymer with a silicon-containing functional group, a polyolefin elastomer containing an isoprene unit, an ethylene-vinyl acetate copolymer, a photoinitiator and an auxiliary agent.

2. The UV-curable polyolefin hot melt adhesive according to claim 1, wherein the raw materials of the UV-curable polyolefin hot melt adhesive comprise, by weight, 20-45 parts of an olefin modified polymer having a silicon-containing functional group, 20-45 parts of a polyolefin elastomer containing an isoprene unit, 5-20 parts of an ethylene-vinyl acetate copolymer, 1-2 parts of a photoinitiator, and 20-53 parts of an auxiliary agent.

3. The UV-curable polyolefin hot melt adhesive according to claim 1 or 2, wherein the auxiliary agents comprise viscosity modifiers, tackifying resins, plasticizers, and antioxidants.

4. The UV-curable polyolefin hot melt adhesive according to claim 3, wherein said olefin-based modified polymer having a silicon-containing functional group is a modified polymer based on a copolymer of modified ethylene, propylene and butene having an alkoxysilyl group.

5. The UV-curable polyolefin hot melt adhesive according to claim 3, wherein the polyolefin elastomer containing isoprene units is at least one of an isobutylene-isoprene copolymer elastomer, a styrene-isoprene-styrene block copolymer elastomer, and a styrene-isoprene-butadiene-styrene block copolymer elastomer.

6. The UV-curable polyolefin hot melt adhesive according to claim 3, wherein said ethylene-vinyl acetate copolymer is at least one of VINNEX N100, VINNAPASS UW 10fs, VINNAPAS C341, VINNAPAS C501 and VINNAPASN100 SP.

7. The UV-curable polyolefin hot melt adhesive according to claim 3, wherein said photoinitiator is 2, 2-dimethoxy-2-phenylacetophenone, 1-hydroxy-cyclohexyl-phenyl ketone, 2-hydroxy-2-methyl-phenyl acetone, 2-hydroxy-2-methyl-p-hydroxyethyl etheryl phenyl acetone, benzophenone, 4-methyl-benzophenone, 4-phenyl-benzophenone, 4-chlorobenzophenone, 4' -bis (dimethylamino) benzophenone, 2,4, 6-trimethylbenzoyl-diphenylphosphine oxide, ethyl 2,4, 6-trimethylbenzoylphosphonate, 2,4, 6-trimethylbenzoyl-ethoxy-phenylphosphine oxide, phosphorus oxide, At least one of bis (2,4, 6-trimethylbenzoyl) phenylphosphoric oxide, 2-methyl-1- (4-methylthiophenyl) -2-morpholine-1-one, or 2-phenylbenzyl-2-dimethylamine-1- (4-morpholinylbenzyl phenyl) butanone.

8. The UV-curable polyolefin hot melt adhesive according to claim 3, wherein said viscosity modifier is at least one of modified Fischer-Tropsch wax, paraffin wax, microcrystalline wax, polyethylene wax, oxidized polyethylene wax, polypropylene wax, and Sasol wax; the tackifying resin is at least one of hydrogenated petroleum resin, hydrogenated rosin resin and styrene modified resin; the plasticizer is at least one of di (2-ethylhexyl) phthalate, dibutyl phthalate or dioctyl phthalate; the antioxidant is at least one of antioxidant 1010, antioxidant 1076, antioxidant CA, antioxidant 164, antioxidant DNP, antioxidant DLTP, antioxidant TNP, antioxidant TPP, antioxidant MB or antioxidant 264.

9. The method for preparing the UV-curable polyolefin hot melt adhesive according to any one of claims 1 to 8, wherein the method comprises the steps of mixing the olefin modified polymer containing the silicon functional group, the polyolefin elastomer containing the isoprene unit, the ethylene-vinyl acetate copolymer and other additives except the plasticizer, and stirring at 150 ℃ and 300rpm for 1h until the materials are completely melted and uniformly mixed; and then adding a photoinitiator and an auxiliary agent containing a plasticizer, stirring at the rotating speed of 300rpm at 150 ℃ for 0.5h, discharging to an aluminum foil packaging bag, sealing to obtain the polyolefin hot melt adhesive, and reacting under the protection of inert gas in the whole process.

10. The use of the UV curable polyolefin hot melt adhesive of any one of claims 1 to 8 for bonding to a battery packaging material.

Technical Field

The invention belongs to the technical field of hot melt adhesive bonding of electric devices, relates to a UV (ultraviolet) curing polyolefin hot melt adhesive and a preparation method thereof, and particularly relates to a UV curing polyolefin hot melt adhesive for edge folding bonding of a battery packaging material and a preparation method thereof.

Background

The lithium ion battery has high energy density, more circulative times, weak memory effect and strong size designability, is one of the most commonly used power supplies at present, and is widely applied to the fields of consumer electronics, living electric appliances, new energy automobiles and the like.

The adhesive plays an important role in the design and production of the lithium ion battery, and the sealing of the lithium ion battery packaging material needs the adhesive. Adhesives for lithium ion batteries tend to meet the following requirements: firstly, the adhesive has excellent electrolyte resistance, and the adhesiveness of the adhesive cannot be lost under the long-term action of the electrolyte; secondly, the adhesive has high enough initial adhesion so as to facilitate the rapid positioning of the adhesive piece; thirdly, the use process is simple and the operation is convenient.

The non-reactive polyolefin adhesive can be used for sealing packaging materials of lithium ion batteries. The polyolefin has stable chemical structure and is not easy to generate chemical reaction with electrolyte. Patent CN104245872A discloses a non-reactive hot-melt adhesive with polyolefin as the main component, which is used for sealing the packaging material of lithium ion battery electrolyte. Patent CN104559846B discloses an adhesive containing polyolefin as a main component and having no tackiness at normal temperature, which can generate adhesive force at high temperature of 85 ℃ or higher and high pressure, and can be used for bonding and fixing a battery core and a battery outer packaging material.

In the sealing and bonding of lithium ion battery packaging materials, the requirement for initial adhesion is particularly high for the fold-over bonding, since the fold-over part is subjected to great stress. For the edge folding and bonding of the lithium ion battery packaging material, the glue dispensing is the most appropriate glue applying process, and both the efficiency and the process quality can be considered. For the above hem bonding, the existing non-reactive polyolefin hot melt adhesive has two problems: firstly, the viscosity of glue is too high, so that the requirement on the dispensing temperature is too high, and the phenomenon of wire drawing is easy to occur in the dispensing process; secondly, the initial adhesion is not strong enough, and a long pressure maintaining time is needed, which brings negative effects on the production efficiency of the lithium ion battery.

The UV curing technique is a technique of initiating a polymerization reaction by UV irradiation to thereby effect curing. By UV curing, the monomers or prepolymers can be polymerized rapidly to form, in a short time, polymeric products having very high molecular weights and even cross-linked structures. The existing UV curing adhesive in the market is mainly shadowless adhesive, is applied to the bonding of transparent base materials, and cannot have the performance of edge folding bonding of lithium ion battery packaging materials. The UV curing technology is applied to the field of polyolefin hot melt adhesives, and further on the basis, the polyolefin hot melt adhesives meeting the requirements of lithium ion battery packaging materials, especially folding edge bonding, are developed through reasonable proportioning of polymer components and auxiliaries, which is a research and development direction in urgent need at present.

Disclosure of Invention

In view of the above, the invention aims to provide a UV-curable polyolefin hot melt adhesive which has low viscosity and strong initial adhesion and can be used for edge folding and bonding of lithium ion battery packaging materials. Also provides a preparation method of the UV-cured polyolefin hot melt adhesive.

In order to achieve the purpose, the invention provides the following technical scheme:

1. the UV curing polyolefin hot melt adhesive for bonding the battery packaging material comprises the following raw materials: the modified polymer comprises an olefin modified polymer with a silicon-containing functional group, a polyolefin elastomer containing an isoprene unit, an ethylene-vinyl acetate copolymer, a photoinitiator and an auxiliary agent.

Furthermore, the raw materials of the UV-cured polyolefin hot melt adhesive comprise, by weight, 20-45 parts of an olefin modified polymer with a silicon-containing functional group, 20-45 parts of a polyolefin elastomer containing an isoprene unit, 5-20 parts of an ethylene-vinyl acetate copolymer, 1-2 parts of a photoinitiator and 20-53 parts of an auxiliary agent.

Furthermore, the auxiliary agent comprises a viscosity regulator, tackifying resin, a plasticizer and an antioxidant.

Further, the auxiliary agent comprises 10-25 parts of viscosity regulator, 10-25 parts of tackifying resin, 1-3 parts of plasticizer and 0.01-0.02 part of antioxidant.

Further, the olefin-based modified polymer having a silicon-containing functional group is a modified polymer based on a copolymer of modified ethylene, propylene and butene having an alkoxysilyl group.

Further, the olefin-based modified polymer having a silicon-containing functional group is an amorphous poly-alpha-olefin of companies, such as: at least one of VESSTOPLAST EP2412, VESSTOPLAST EP2403, VESSTOPLAST 206.

Further, the polyolefin elastomer containing an isoprene unit is at least one of an isobutylene-isoprene copolymer elastomer, a styrene-isoprene-styrene block copolymer elastomer, and a styrene-isoprene-butadiene-styrene block copolymer elastomer.

Further, the polyolefin elastomer containing isoprene units is at least one of an isobutylene-isoprene copolymer elastomer, a styrene-isoprene-styrene block copolymer elastomer and a styrene-isoprene-butadiene-styrene block copolymer elastomer, wherein the isobutylene-isoprene copolymer elastomer has a melt index of 200 ℃/5kg of 100-200 g/10min and a Shore hardness of 20-50.

Further, the ethylene-vinyl acetate copolymer is at least one of VINNEX N100, VINNAPAS UW 10fs, VINNAPAS C341, VINNAPAS C501, and VINNAPAS N100 SP.

Further, the photoinitiator is 2, 2-dimethoxy-2-phenylacetophenone, 1-hydroxy-cyclohexyl-phenyl ketone, 2-hydroxy-2-methyl-phenyl acetone, 2-hydroxy-2-methyl-p-hydroxyethyl ether phenyl acetone, benzophenone, 4-methyl-benzophenone, 4-phenyl-benzophenone, 4-chlorobenzophenone, 4' -bis (dimethylamino) benzophenone, 2,4, 6-trimethylbenzoyl-diphenyl phosphine oxide, ethyl 2,4, 6-trimethylbenzoyl phosphonate, 2,4, 6-trimethylbenzoyl-ethoxy-phenyl phosphorus oxide, bis (2,4, 6-trimethylbenzoyl) phenyl phosphorus oxide, phosphorus oxide, 2-methyl-1- (4-methylthiophenyl) -2-morpholine-1-one or 2-phenylbenzyl-2-dimethylamine-1- (4-morpholine benzyl phenyl) butanone.

Further, the viscosity regulator is at least one of modified Fischer-Tropsch wax, paraffin wax, microcrystalline wax, polyethylene wax, oxidized polyethylene wax, polypropylene wax and saso wax; the tackifying resin is at least one of hydrogenated petroleum resin, hydrogenated rosin resin and styrene modified resin; the plasticizer is at least one of di (2-ethylhexyl) phthalate, dibutyl phthalate or dioctyl phthalate; the antioxidant is at least one of antioxidant 1010, antioxidant 1076, antioxidant CA, antioxidant 164, antioxidant DNP, antioxidant DLTP, antioxidant TNP, antioxidant TPP, antioxidant MB or antioxidant 264.

Further, the tackifying resin is at least one of hydrogenated petroleum resin, hydrogenated rosin resin and styrene modified resin with the softening point of 70-90 ℃.

2. A preparation method of UV curing polyolefin hot melt adhesive for bonding battery packaging materials is characterized in that olefin modified polymer containing silicon functional groups, polyolefin elastomer containing isoprene units, ethylene-vinyl acetate copolymer and other additives except plasticizer are mixed, and then stirred at 150 ℃ at the rotating speed of 300rpm for 1h until the materials are completely melted and uniformly mixed; and then adding a photoinitiator and an auxiliary agent containing a plasticizer, stirring at the rotating speed of 300rpm at 150 ℃ for 0.5h, discharging to an aluminum foil packaging bag, sealing to obtain the polyolefin hot melt adhesive, and reacting under the protection of inert gas in the whole process.

Further, the inert gas is nitrogen.

3. The adhesive application of the UV-cured polyolefin hot melt adhesive on a battery packaging material.

And further, the UV-cured polyolefin hot melt adhesive is applied to the edge folding of the ion battery packaging material in an adhesion manner.

Further, the packaging material is a polyamide film.

The invention has the beneficial effects that: the invention provides a UV-cured polyolefin hot melt adhesive, which introduces a polyolefin elastomer containing an isoprene unit, which can generate free radical photopolymerization, into the polyolefin hot melt adhesive. After irradiation with UV light, the polyolefin elastomer containing isoprene units undergoes a photocuring reaction, and the molecular weight rapidly increases in a short time, with a consequent rapid increase in cohesive energy. Therefore, the polyolefin hot melt adhesive provided by the invention has small molecular weight and viscosity in the early period, is convenient for glue dispensing and is not easy to generate wire drawing when in use, and can generate molecules with extremely high molecular weight after being irradiated by UV light, thereby generating extremely high initial adhesion. In this way, the invention provides a polyolefin hot melt adhesive with low viscosity and high initial adhesion. The requirement of the polyolefin hot melt adhesive on the sizing temperature is lower than that of the high-viscosity polyolefin hot melt adhesive on the market, the wire drawing phenomenon is not easy to occur in the sizing process, the initial adhesion is extremely high, the pressure maintaining time is shortened, the production process is facilitated to be simplified, and the production efficiency is improved. In addition, the polyolefin hot melt adhesive prepared by the invention also has excellent electrolyte resistance. The adhesive can be used for bonding the packaging material of the lithium ion battery, in particular to the edge folding bonding of the battery structure.

Drawings

In order to make the object, technical scheme and beneficial effect of the invention more clear, the invention provides the following drawings for explanation:

FIGS. 1 to 5 are graphs showing adhesion tests of hot melt adhesives prepared in example 4 and comparative examples 1 to 3 to actual cell samples, wherein FIG. 1 is a graph showing the case before the cell was bound and not adhered;

FIG. 2 shows the adhesion test of the hot melt adhesive of example 4 to an actual battery sample;

FIG. 3 shows the adhesion test of the hot melt adhesive of comparative example 1 to an actual battery sample;

FIG. 4 shows the adhesion test of the hot melt adhesive of comparative example 2 to an actual battery sample;

FIG. 5 shows the adhesion test of the hot melt adhesive of comparative example 3 to an actual cell sample;

the battery used was a 3677A4 lithium ion polymer cell manufactured by Huizhou lithium Wei New energy technology, Inc. The hot melt adhesive prepared in example 4 was dispensed onto the folded edge of the cell at 140 ℃ using a three-axis dispenser, and then the adhesive layer was irradiated with a UV-LED light source having a wavelength of 365nm at an irradiation dose of 3000mJ/cm2, and then the folded edge was folded and adhered onto the cell body, and the pressure was maintained at room temperature for 30s and at a holding pressure of 3.5kgf/cm 2. For the hot melt adhesives prepared in comparative examples 1 to 3, the adhesive was dispensed to the folded edge of the battery at 140 ℃ using a three-axis dispenser, and then the folded edge was folded and adhered to the battery body, and the pressure was maintained at room temperature for 30 seconds, with a holding pressure of 3.5kgf/cm 2. The time point at which the pressure holding was completed was regarded as T0, and the battery sample was observed by standing.

As can be seen from the figure, when T is 12min, the folded edge part of the sample adhered by the hot melt adhesive prepared in comparative example 1 springs open; when T is 13min, the folded edge part of the sample adhered by the hot melt adhesive prepared in the comparative example 2 is bounced off; when T is 17min, the folded edge part of the sample adhered by the hot melt adhesive prepared in the comparative example 3 is bounced off; when T is 4h, the sample bonded with the hot melt adhesive prepared in example 4 still did not pop open. The experiment was stopped when T was 4 h.

Comparing example 4 with comparative examples 1 to 3, it can be seen that the present invention improves the molecular weight and crosslinking degree of the polyolefin hot melt adhesive by the UV curing technique, and realizes the rapid bonding positioning of the battery fold. The components in the comparative example do not undergo a UV curing reaction and do not achieve the technical problems solved by the present invention.

Detailed Description

Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings. The experimental procedures, in which specific conditions are not specified in the examples, are generally carried out under conventional conditions or under conditions recommended by the manufacturers.

The UV curing polyolefin hot melt adhesive for edge folding and bonding of lithium ion battery packaging materials comprises the following components in parts by weight: 20-45 parts of an olefin modified polymer with a silicon-containing functional group, 20-45 parts of a polyolefin elastomer containing an isoprene unit, 5-20 parts of an ethylene-vinyl acetate copolymer, 1-2 parts of a photoinitiator, 10-25 parts of a viscosity regulator, 10-25 parts of tackifying resin, 1-3 parts of a plasticizer and 0.01-0.02 part of an antioxidant.

The olefin modified polymer having a silicon-containing functional group is a modified polymer based on a copolymer of modified ethylene having an alkoxysilyl group and propylene and butene, and is preferably at least one of VESSTOPLAST EP2412, VESSTOPLAST EP2403 and VESSTOPLAST 206 (amorphous poly-alpha-olefin) from Windsor.

The polyolefin elastomer containing isoprene units is at least one of an isobutylene-isoprene copolymer elastomer, a styrene-isoprene-styrene block copolymer elastomer and a styrene-isoprene-butadiene-styrene block copolymer elastomer, and preferably at least one of an isobutylene-isoprene copolymer elastomer, a styrene-isoprene-styrene block copolymer elastomer and a styrene-isoprene-butadiene-styrene block copolymer elastomer, wherein the isobutylene-isoprene copolymer elastomer, the styrene-isoprene-styrene block copolymer elastomer and the styrene-isoprene-butadiene-styrene block copolymer elastomer have a melt index of 200 ℃/5kg of 100-200 g/10min and a Shore hardness of 20-50.

The ethylene-vinyl acetate copolymer is at least one of VINNEX N100, VINNAPASS UW 10fs, VINNAPAS C341, VINNAPAS C501 and VINNAPAS N100SP of Wacker.

The photoinitiator is 2, 2-dimethoxy-2-phenylacetophenone, 1-hydroxy-cyclohexyl-phenyl ketone, 2-hydroxy-2-methyl-phenyl acetone, 2-hydroxy-2-methyl-p-hydroxyethyl ether phenyl acetone, benzophenone, 4-methyl-benzophenone, 4-phenyl-benzophenone, 4-chlorobenzophenone, 4' -bis (dimethylamino) benzophenone, 2,4, 6-trimethylbenzoyl-diphenylphosphine oxide, 2,4, 6-trimethylbenzoyl phosphonic acid ethyl ester, 2,4, 6-trimethylbenzoyl-ethoxy-phenylphosphoric oxide, bis (2,4, 6-trimethylbenzoyl) phenylphosphoric oxide, poly (ethylene glycol) ether, 2-methyl-1- (4-methylthiophenyl) -2-morpholine-1-one or 2-phenylbenzyl-2-dimethylamine-1- (4-morpholine benzyl phenyl) butanone.

The viscosity regulator is at least one of modified Fischer-Tropsch wax, paraffin wax, microcrystalline wax, polyethylene wax, oxidized polyethylene wax, polypropylene wax and saso wax.

The tackifying resin is at least one of hydrogenated petroleum resin, hydrogenated rosin resin and styrene modified resin, and preferably at least one of hydrogenated petroleum resin, hydrogenated rosin resin and styrene modified resin with a softening point of 70-90 ℃.

The plasticizer is at least one of di (2-ethylhexyl) phthalate, dibutyl phthalate or dioctyl phthalate.

The antioxidant is at least one of antioxidant 1010, antioxidant 1076, antioxidant CA, antioxidant 164, antioxidant DNP, antioxidant DLTP, antioxidant TNP, antioxidant TPP, antioxidant MB or antioxidant 264.

According to the invention, the formula provided by the invention is finally obtained through continuously testing the components such as the olefin modified polymer containing the silicon functional group, the polyolefin elastomer containing the isoprene unit, the ethylene-vinyl acetate copolymer, the rest of the auxiliary agents and the like and the content ratio of the components. Provides a polyolefin hot melt adhesive with low viscosity and high initial adhesion. The requirement of the polyolefin hot melt adhesive on the sizing temperature is lower than that of the high-viscosity polyolefin hot melt adhesive on the market, the wire drawing phenomenon is not easy to occur in the sizing process, the initial adhesion is extremely high, the pressure maintaining time is shortened, the production process is facilitated to be simplified, and the production efficiency is improved. Wherein the content of the polyolefin elastomer containing isoprene units determines the content of the light-cured component, and if the content is too low, the improvement of the cohesion after light curing is not large enough; if the amount is too high, the degree of photocuring becomes too high, resulting in rapid drying of the adhesive layer after UV irradiation and extremely short working time.

The olefin modified polymer containing silicon functional groups is a key action component in the olefin hot melt adhesive provided by the invention, and provides adhesion on one hand and cohesion on the other hand. The ethylene-vinyl acetate copolymer functions similarly to the silicon functional group-containing olefin-based modified polymer to provide adhesion and cohesion, but the two functions are independent of each other in the present invention, and the silicon functional group-containing olefin-based modified polymer has stronger adhesion to a low-polar component in an adherend and the ethylene-vinyl acetate copolymer has stronger adhesion to a high-polar component in the adherend. Too much of either of them leads to too little of the other, so that too few do not exert an adhesive effect on the adherend. Therefore, the invention obtains the optimal proportioning through a large amount of experiments. The polyolefin elastomer containing isoprene units is further synergistic with the olefin-based modified polymer containing silicon functional groups and the ethylene-vinyl acetate copolymer, and the content is optimized so that the content enhances the remarkable influence of the photocuring on the cohesive force in a minimum range. The polyolefin hot melt adhesive provided by the invention is applied with glue at about 140 ℃, then is immediately subjected to UV illumination, and the subsequent operable time is about 30-60s, the operable time is right, and the workability is strong.