CN116001384A

CN116001384A - Metal composite film with excellent heat resistance, moisture barrier and insulating properties

Info

Publication number: CN116001384A
Application number: CN202211592789.5A
Authority: CN
Inventors: 庄志; 张茜; 程跃
Original assignee: Jiangsu Ruijie New Material Technology Co ltd
Current assignee: Jiangsu Ruijie New Material Technology Co ltd
Priority date: 2022-12-13
Filing date: 2022-12-13
Publication date: 2023-04-25

Abstract

The metal composite film provided by the invention comprises the following components: the heat-seal adhesive comprises a metal layer, an inner layer adhesive layer, a heat-seal resin layer, an outer layer adhesive layer and an outer layer, wherein the outer layer is arranged on one side of the metal layer, the heat-seal resin layer is arranged on the other side of the metal layer, the inner layer adhesive layer is arranged between the metal layer and the heat-seal resin layer, the outer layer adhesive layer is arranged between the outer layer and the metal layer, and the inner layer adhesive layer contains acid modified polypropylene, an epoxy curing agent, an amine accelerator, a bridging agent containing an anhydride group compound, or contains acid modified polypropylene, an isocyanate curing agent and a bridging agent containing an anhydride group compound.

Description

Metal composite film with excellent heat resistance, moisture barrier and insulating properties

Technical Field

The present invention relates to the field of electronic components, and more particularly, to a metal composite film having excellent heat resistance, moisture barrier and insulation properties.

Background

The lithium ion battery is divided into three types of square, cylindrical and soft package, wherein the square and cylindrical shells mainly adopt hard shells such as aluminum alloy, stainless steel and the like, the aluminum alloy shell material can be aluminum, and the soft package shell formed by laminating metal and resin adopts a metal composite film, so that the defect of inflexible appearance design of the hard-packaged battery can be overcome.

The metal composite film mainly comprises two product types, namely a dry product and a thermal product, wherein the dry product comprises an outer base material resin layer, an outer adhesive layer, an intermediate metal layer, an inner adhesive layer and a thermal welding resin layer from outside to inside. The thermal method comprises an outer base material resin layer, an outer adhesive layer, an intermediate metal layer and an inner thermal welding resin layer from outside to inside, and is used as an outer package material of the battery.

The battery has the advantages that the requirements of higher specifications are put forward for the high temperature resistance, corrosion resistance, durability and safety of the outer packaging material, as the 3C products can generate certain heat in the charging and discharging process, the power lithium ion battery can generate more heat, the service life of the lithium ion battery for EV is required to be more than 10 years when the service life of the 3C equipment is shorter than about 2-5 years, and certain shortages exist in the aspect of long service life, in addition, fire accidents of the lithium ion battery often occur, the doubt in the aspect of safety still exists, and the lithium ion battery also has shortages in the aspect of insulating property.

At present, polypropylene is mainly used as an inner adhesive layer, the melting point of the polypropylene is between 70 ℃ and 80 ℃, and in addition, the acid grafting rate of the acid modification of the inner adhesive acid modified polypropylene is low, usually below 2%, and the polypropylene is partially hydrolyzed in a storage environment. And the inner layer adhesive has insufficient units for reactive crosslinking in the presence of a curing agent. The metal composite film has remarkable defects in heat resistance, corrosion resistance, durability, safety and the like. In actual use, the swelling and the permeation of the electrolyte often occur, so that the stable operation of a chemical system in the battery is reduced, the gas can be blown open under severe conditions, the use safety is seriously affected, and the use requirement of the all-solid-state battery of the next generation product cannot be met.

Disclosure of Invention

In view of the above, it is desirable to provide a metal composite film having excellent heat resistance, moisture barrier and insulation properties, which further satisfies heat resistance of an inner adhesive layer and liquid heat sealing resistance after heat sealing and in an electrolytic environment of an electrolyte as a content, and insulation properties of a battery to an external packaging material by material co-action.

In order to achieve the above purpose, the technical scheme of the invention is realized as follows:

the invention provides a metal composite film, which comprises the following components: the heat-seal adhesive comprises a metal layer, an inner layer adhesive layer, a heat-seal resin layer, an outer layer adhesive layer and an outer layer, wherein the outer layer is arranged on one side of the metal layer, the heat-seal resin layer is arranged on the other side of the metal layer, the inner layer adhesive layer is arranged between the metal layer and the heat-seal resin layer, the outer layer adhesive layer is arranged between the outer layer and the metal layer, and the inner layer adhesive layer contains acid modified polypropylene, an epoxy curing agent, an amine accelerator, a bridging agent containing an anhydride group compound, or contains acid modified polypropylene, an isocyanate curing agent and a bridging agent containing an anhydride group compound.

Preferably, the inner adhesive layer contains acid modified polypropylene, isocyanate curing agent and bridging agent containing anhydride group compound.

Preferably, the bridging agent has at least 1 anhydride, the anhydride of which comprises one or more of a linear anhydride, an aromatic anhydride, a cycloaliphatic anhydride.

Preferably, the bridging agent has 4 to 20 carbon atoms and the degree of unsaturation of the olefin is 1 or more.

Preferably, the bridging agent contains a carbon-carbon double bond and a methyl group.

Preferably, the acid value of the bridging agent is from 100mgKOH/g to 800mgKOH/g.

Preferably, the acid-modified polypropylene contains a polypropylene resin modified by a grafting treatment with a carboxylic acid or an anhydride thereof, and has an acid value of 1 to 5, a melting point of 70 to 130 ℃, and a weight average molecular weight of 10 to 25 ten thousand.

Preferably, the bridging agent accounts for 10 to 100% of the epoxy curing agent by weight.

Preferably, the amine accelerator comprises one or more of aliphatic amine and aromatic amine curing agents, and the weight part of the amine accelerator relative to the acid modified polypropylene is 0.02 to 2.

Preferably, the amine accelerator comprises an aromatic amine curing agent, wherein the aromatic amine curing agent is secondary amine, tertiary amine aromatic amine compound and N, N-dimethylbenzylamine, and the weight part of the amine accelerator relative to the acid modified polypropylene is 0.02-2.

Preferably, the amine promoter comprises N, N-dimethylbenzylamine.

Preferably, the epoxy curing agent is selected from bisphenol A epoxy resin, bisphenol F epoxy resin, phenol type novolac epoxy, o-cresol type novolac epoxy, triphenol methane type epoxy, tetraphenol ethane type epoxy, polyphenol type glycidyl ether epoxy resin, aliphatic glycidyl ether epoxy resin, and glycidyl ester type epoxy resin.

Preferably, the epoxy curing agent is bisphenol A epoxy resin and phenolic epoxy resin, the epoxy value of the epoxy curing agent is 0.2mol/100g to 2.0mol/100g, and the weight part of the epoxy curing agent relative to the acid modified polypropylene is 2 to 15.

Preferably, the isocyanate curing agent contains more than 50% of one or more of hexamethylene diisocyanate and pentamethylene diisocyanate, and the ratio NCO/COOH of the number of moles of carboxyl groups in the acid-modified polypropylene to the number of moles of isocyanate groups (NCO value) of the isocyanate curing agent is 1.36 to 4.32.

According to the invention, the inner layer bonding layer is composed of the bridging agent containing acid modified polypropylene, epoxy curing agent, amine accelerator and acid anhydride group-containing compound, or the bridging agent containing acid modified polypropylene, isocyanate curing agent and acid anhydride group-containing compound, the epoxy curing agent can have high heat distortion temperature after crosslinking reaction, and has high temperature resistance, meanwhile, the bridging agent molecular structure of the acid anhydride group-containing compound contains little longer carbon-carbon double bond and methyl, the folding winding is less than that of the acid modified polypropylene, the acid anhydride functional group can react with the epoxy curing agent more, the crosslinking density is increased, the high temperature resistance and electrolyte resistance are further improved, the structural stability is higher, the molecular chain is not easy to break, the insulating capability is stronger, and the electrical insulation performance and the mechanical performance of the bridging agent are superior to those of the prior art.

Drawings

Fig. 1 is a schematic structural view of a metal composite film according to the present invention.

Description of the component reference numerals

(1) Metal layer

(2) Inner layer adhesive layer

(3) Thermal welding resin layer

(4) Outer adhesive layer

(5) An outer layer

Detailed Description

The following detailed description of the invention refers to the accompanying drawings. It should be understood that the detailed description and specific examples, while indicating and illustrating the invention, are not intended to limit the invention.

The endpoints and any values of the ranges disclosed herein are not limited to the precise range or value, and are understood to encompass values approaching those ranges or values. For numerical ranges, one or more new numerical ranges may be found between the endpoints of each range, between the endpoint of each range and the individual point value, and between the individual point value, in combination with each other, and are to be considered as specifically disclosed herein.

As shown in fig. 1, one embodiment of the present invention provides a metal composite film, which includes: the heat-seal adhesive comprises a metal layer (1), an inner layer adhesive layer (2), a heat-seal resin layer (3), an outer layer adhesive layer (4) and an outer layer (5), wherein the outer layer (5) is arranged on one side of the metal layer (1), the heat-seal resin layer (3) is arranged on the other side of the metal layer (1), the inner layer adhesive layer (2) is arranged between the metal layer (1) and the heat-seal resin layer (3), and the outer layer adhesive layer (4) is arranged between the outer layer (5) and the metal layer (1).

In this embodiment, the inner adhesive layer (2) contains an acid-modified polypropylene, an epoxy-based curing agent, an amine accelerator, a bridging agent for an acid-anhydride group-containing compound, or contains an acid-modified polypropylene, an isocyanate curing agent, and a bridging agent for an acid-anhydride group-containing compound.

Specifically, the inner adhesive layer (2) contains acid modified polypropylene, isocyanate curing agent and bridging agent containing anhydride group compound.

Specifically, an anticorrosive layer is further provided between the heat-fusible resin layer (3) and the metal layer (1), and the carbon component from the anticorrosive layer and the metal component from the metal layer (1) are distributed in a gradient and inclined manner. The anticorrosive layer is formed by drying anticorrosive liquid, the components of elements on the metal anticorrosive layer on the side of the thermal welding resin layer (3) are distributed in a gradient way, the content ratio of carbon (C) on the outermost layer of the anticorrosive layer on the side of the thermal welding resin layer (3) is more than or equal to 40% and less than or equal to 100%, the content of intermediate metal elements is less than or equal to 5%, and the content of the intermediate metal elements is more than or equal to 10% and less than or equal to 70% in the layer, 20nm of which the surface layer of the anticorrosive layer is downwards. In the layer 40nm down from the surface layer of the anti-corrosion layer, the content of the intermediate metal element is more than or equal to 20% and less than or equal to 100%.

Specifically, the bridging agent has at least 1 acid anhydride, the acid anhydride of which includes one or more of a linear acid anhydride, an aromatic acid anhydride, and a cycloaliphatic acid anhydride.

Specifically, the linear anhydride may be selected from (2, 7-octadien-1-yl) succinic anhydride, 2-buten-1-yl succinic anhydride, (2-methyl-2-propen-1-yl) succinic anhydride, 2-nonenylsuccinic anhydride, N-octenyl succinic anhydride, 2-octenyl succinic anhydride, N-dodecyl succinic anhydride, dodecenyl succinic anhydride. The aromatic anhydride may be selected from phthalic anhydride, methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, trimellitic anhydride, pyromellitic dianhydride, etc., and the alicyclic anhydride may be selected from maleic anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, methylnadic anhydride, etc.

In order to ensure the bridging effect of the bridging agent, and to connect the metal layer and the heat-fusible resin layer with good results, a certain length of chain length is required, and in addition, too long chain length can bend and fold, reducing the connection of the acid anhydride with the metal layer and the heat-fusible resin layer, and affecting the crosslinking with the epoxy curing agent, preferably, the bridging agent has 4 to 20 carbon atoms and the degree of unsaturation of the olefin is 1 or more. Specifically, the compound is one or more of 2-nonenylsuccinic anhydride, n-octenyl succinic anhydride, phthalic anhydride, methyltetrahydrophthalic anhydride and dodecenylsuccinic anhydride.

Specifically, the bridging agent contains a carbon-carbon double bond (-c=c) and a methyl group (-CH 3). The CH 3 and the carboxylic acid have steric hindrance when being very close to each other, the cured epoxy resin has more compact molecular structure, higher Tg and better high temperature resistance. The cured epoxy resin has compact molecular structure, is favorable for the formation of deep traps, has more regular and compact internal network structure of the epoxy material, has more number of the deep traps, enhances the binding force of charges, ensures that the charges entering the deep traps are not easy to escape, has excellent insulating property, simultaneously, -CH 3 belongs to a group for supplying electricity, has induction effect, reduces the reactivity of anhydride groups due to the existence of-CH 3 on a molecular chain, has longer pot life and better process operability after being mixed with the epoxy resin at normal temperature. The distance between the two carbon atoms of C=C is shorter than the single bond distance of-C-C, the structural stability is higher, the molecular chain is not easy to break, and the insulating capability is stronger.

Specifically, the acid value of the bridging agent is 100mgKOH/g to 800mgKOH/g.

Specifically, the acid-modified polypropylene contains a polypropylene resin modified by a grafting treatment with a carboxylic acid or an anhydride thereof, and has an acid value of 1 to 5, a melting point of 70 to 130 ℃, and a weight average molecular weight of 10 to 25 ten thousand.

The inner adhesive layer product composed of the acid-modified polypropylene and the curing agent was set to a heating condition of 10 ℃/min, and when the amount of heat generation relative to the heating time was measured, at least two or more points showed heat absorption due to dissolution of the inner adhesive layer. Wherein, in the endothermic curve composed of the temperature rise time and the endothermic quantity, an area quantity (ap_1) with the largest area formed by the change point of the temperature and the endothermic quantity connecting the endothermic curve is formed, when the endothermic peak temperature is set as tap_1, tap_1 is in the range of 85 ℃ to 130 ℃, and further, the endothermic temperature peak (tap_2) with the area (ap_2) below the largest area quantity (ap_1) is in the range of 50 ℃ to 80 ℃. Further, there is an endothermic peak between 100 ℃ and 130 ℃.

The heat absorption peak temperature (tap_1) of the reaction product of the acid-modified polypropylene and the curing agent when forming the maximum area (ap_1) in the reaction product affects the heat resistance of the inner adhesive layer. When the temperature is lower than 85 ℃, the heat resistance is insufficient, and when the electrolyte solution as the content is impregnated, the peeling strength between the metal layer and the heat-sealing resin layer is lowered during high-temperature storage, and further the heat-sealing resin layer peels off from the metal layer, thereby deteriorating the durability.

In addition, when the endothermic peak temperature (tap_1) exceeds 100 ℃ at the time of forming the maximum area (ap_1), it is necessary to raise the melting point of the acid-modified polypropylene. If the melting point of the acid-modified polypropylene is increased, the acid-modified polypropylene is difficult to dissolve or disperse in a solvent such as an organic solvent or water. But the reactivity with the curing agent is increased. Therefore, even when the metal layer is soluble or dispersible, the coating property is deteriorated due to the high viscosity, and the reactivity with the curing agent is high, and the metal layer starts to react and solidify in the coating step, so that the coating amount and physical properties of the metal layer are not stable.

When the heat absorption temperature peak (tap_2) of the area (ap_2) of the maximum area amount (ap_1) or less is lower than 50 ℃, the heat resistance of the inner adhesive layer is insufficient, and when the electrolyte as the content permeates, the peel strength between the metal layer and the heat-sealing resin layer is lowered during high-temperature storage, and further the heat-sealing resin layer peels off from the metal layer, thereby deteriorating the durability.

When the endothermic temperature peak k (tap_2) forming the area (ap_2) of the maximum area amount (ap_1) or less exceeds 80 ℃, the aforementioned maximum area (ap_1) and the area (ap_2) of the maximum area amount (ap_1) or less are partially overlapped. In this case, the heat resistance, the chemical resistance, and the electrolyte resistance of the content do not cause much problem.

Specifically, the area (ap_2) of the maximum area (ap_1) of the endothermic temperature peak (tap_1) formed in the range of 85 ℃ to 100 ℃ and the area (ap_2) of the maximum area (ap_1) or less of the endothermic temperature peak (tap_2) formed in the range of 50 ℃ to 80 ℃, preferably ap_1+.ap_2. More preferably, the area (ap_2) of the maximum area (ap_1) is 80% or less, relative to the maximum area (ap_1).

When ap_1 is equal to or larger than ap_2, the heat resistance of the inner adhesive layer, which is a reaction product formed from the acid-modified polypropylene and the curing agent, is improved. When ap_2> ap_1, it is predicted that the content of the low melting point component will be greater than the content of the high melting point component. Therefore, the heat resistance of the function as a high melting point component is lowered.

Specifically, the bridging agent accounts for 10 to 100% of the epoxy curing agent by weight ratio relative to the epoxy curing agent.

As the amount of the acid anhydride group-containing compound increases, the ratio of-CH 3 in the molecular structure of the epoxy system gradually increases, resulting in an increase in the degree of crosslinking between the acid anhydride group-containing compound and the epoxy-based cured product, an increase in rigidity, and an increase in Tg. When the use amount of the acid anhydride group-containing compound is continuously increased, the functional group structure which can open the acid anhydride group in the curing system is less and less, the proportion of the-CH 3 in the epoxy system is difficult to continuously increase, the crosslinking density of the curing system is not increased any more, and the Tg is maintained within a certain range.

When the consumption of the anhydride group-containing compound is increased, the ratio of-CH 3 in the epoxy matrix molecular chain is increased, the molecular chain structure of the epoxy matrix is gradually regular and compact, the formation of the epoxy resin deep trap is facilitated, and the breakdown strength is improved. When the amount of the acid anhydride group-containing compound exceeds 100% by mass of the epoxy-based curing agent, the ratio of-CH 3 in the molecular chain structure decreases, and the long aliphatic chain structure becomes a main structure occupying the molecular chain of the epoxy-based material. The long fatty chain structure is loose, the binding force is small when the molecular chain segment moves (such as rotation), and the formation of shallow traps is facilitated in the epoxy substrate, so that the insulating property is reduced. When the long fatty chain becomes the main structure of the molecular chain of the epoxy base material, the molecular gap of the crosslinked network structure of the epoxy base material becomes large, so that water molecules can enter a crosslinking system more easily, the acting force among the molecules of the epoxy base material is changed, and the stability of the molecular chain structure of the resin is damaged.

Specifically, the amine accelerator comprises one or more of aliphatic amine and aromatic amine curing agents, and the weight part of the amine accelerator relative to the acid modified polypropylene is 0.02-2.

The active hydrogen on the amine can open an epoxy group for crosslinking and curing, and the specific process is ring opening-esterification-etherification. The aliphatic ethanolamine, alicyclic amine, aliphatic amine, quaternary amine salt, urea, may be selected, and specifically may be N, N-dimethylcyclohexylamine, tris (dimethylaminopropyl) amine, quaternary amine salt of 2, 2-dimethylpropionate, 2- { [2- (dimethylamino) ethyl ] methylamino } ethanol, 2,4, 6-tris (dimethylaminomethyl) phenol, triethylenediamine, m-phenylenediamine, o-diaminomethylcyclopentane, N, N-dimethylbenzylamine.

Specifically, the amine accelerator comprises an aromatic amine curing agent, wherein the aromatic amine curing agent is secondary amine, tertiary amine aromatic amine compounds and N, N-dimethylbenzylamine, and the weight part of the amine accelerator relative to the acid modified polypropylene is 0.02-2.

Specifically, the amine promoter includes N, N-dimethylbenzylamine.

Specifically, the epoxy curing agent is selected from bisphenol A epoxy resin, bisphenol F epoxy resin, phenol type phenolic epoxy, o-cresol type phenolic epoxy, triphenol methane type epoxy, tetraphenol ethane type epoxy, polyphenol type glycidyl ether epoxy resin, aliphatic glycidyl ether epoxy resin and glycidyl ester type epoxy resin.

Specifically, the epoxy-based curing agent is bisphenol A epoxy resin and novolac epoxy resin, the epoxy value of which is 0.2mol/100g to 2.0mol/100g, and the weight part of the epoxy-based curing agent relative to the acid-modified polypropylene is 2 to 15.

Specifically, the isocyanate curing agent contains more than 50% of one or more of hexamethylene diisocyanate and pentamethylene diisocyanate, and the ratio NCO/COOH of the number of moles of carboxyl groups in the acid-modified polypropylene to the number of moles of isocyanate groups (NCO value) of the isocyanate curing agent is 1.36 to 4.32.

The present invention will be described in detail by examples.

Example 1

The biaxially oriented nylon film having a base material of 25 μm except the outer layer was laminated on an 8021 aluminum material having a surface wettability of 68dyn/cm and a thickness of 35 μm by an outer layer adhesive (also referred to as an outer layer adhesive layer). The metal layer is subjected to corrosion prevention treatment on two sides of the metal foil to form a corrosion prevention layer. The corrosion-resistant liquid on the two sides of the metal foil is used for carrying out corrosion-resistant treatment. The content ratio of trivalent chromium compound, inorganic acid and organic resin on the surface of the aluminum foil is 2:2:1. the trivalent chromium compound is chromium phosphate, the inorganic acid is nitric acid, and the organic resin is polyacrylic resin.

The inner adhesive layer was formed by laminating an anhydrous maleic anhydride-modified polypropylene solution having a weight average molecular weight of 25 ten thousand and a melting point of 80 to 90 ℃ and an acid value of 2 and a curing agent containing more than 50% of Hexamethylene Diisocyanate (HDI) composed of a trimer having a functionality of 3.4 in an inner lamination manner, and the mass ratio of the acid-modified polypropylene solution (main agent of table 1 below) to the isocyanate curing agent was 100:2.12, the addition of the acid anhydride group-containing compound was 0.15 parts by mass relative to the acid-modified polypropylene.

The solution-type mixture is coated on the metal surface of the composite film of the composite outer base material resin, an inner layer bonding layer with the thickness of 2 mu m is formed after drying, then the inner layer bonding layer is thermally compounded with the bonding surface of 40 mu m heat welding resin at the temperature of 100 ℃, and curing treatment is carried out for 7 days at the temperature of 50 ℃ to form a composite product of an outer base material resin layer (25 mu m) (also called outer layer)/an outer adhesive layer (3 mu m) (also called outer bonding layer)/an intermediate metal layer (also called metal layer)/an inner layer adhesive layer (also called inner layer bonding layer)/an inner heat welding resin layer (40 mu m) (also called heat welding resin layer). The adhesive surface of the 3-layer heat-fusible resin film in contact with the inner adhesive layer was subjected to corona treatment in advance.

From the results shown in Table 1 below, it was found that the metal composite film of the composite product had excellent electrolyte resistance in this example, since the metal composite film was stored in an electrolyte containing 1000ppm of water at 85℃for 14 days, the electrolyte resistance peel strength was 12.69N, and the peel strength maintenance rate was 79%.

Example 2

A biaxially oriented nylon film having a base material layer material of 25 μm except the outer layer was laminated on an 8021-based aluminum material having a surface wettability of 68dyn/cm and a thickness of 35 μm by an outer layer adhesive. And carrying out corrosion prevention treatment on two sides of the metal foil to form a corrosion prevention layer.

The metal layer is subjected to corrosion prevention treatment by using corrosion prevention liquid on two sides of the metal foil. The content ratio of trivalent chromium compound, inorganic acid and organic resin on the surface of the aluminum foil is 2:2:1. the trivalent chromium compound is chromium phosphate, the inorganic acid is nitric acid, and the organic resin is polyacrylic resin.

The inner adhesive layer is formed by laminating an anhydrous maleic anhydride modified polypropylene solution with the weight average molecular weight of 25 ten thousand, the melting point of 80-90 ℃ and the acid value of 2 and a curing agent in an inner lamination mode, wherein the anhydrous maleic anhydride modified polypropylene solution contains more than 50 percent of Hexamethylene Diisocyanate (HDI), the hexamethylene diisocyanate is composed of a trimer, the functionality is 3.4, and the mass ratio of the acid modified polypropylene solution to the isocyanate curing agent is 100:2.12, the addition of the acid anhydride group-containing compound was 0.45 parts by mass relative to the acid-modified polypropylene.

The resulting solution-type mixture was applied to the corrosion-treated metal surface of a composite film of the composite outer base resin, and dried to form an inner adhesive layer having a thickness of 2. Mu.m, and then thermally compounded with the adhesive surface of the 40. Mu.m heat-sealing resin at a temperature of 100℃and further cured at a temperature of 50℃for 7 days to form a composite product of the outer base resin layer (25 μm)/outer adhesive layer (3 μm)/intermediate metal layer/inner adhesive layer/heat-sealing resin layer (40 μm). The adhesive surface of the 3-layer heat-fusible resin film in contact with the inner adhesive layer was subjected to corona treatment in advance.

As is clear from the results in table 1 below, the metal composite film of the composite product was stored in an electrolyte containing 1000ppm of water at 85 ℃ for 14 days, and the peel strength of the electrolyte was 11.84N, and the retention rate of the peel strength was 74%, so that the metal composite film of this example was excellent in electrolyte resistance.

Example 3

The inner adhesive layer is formed by laminating an anhydrous maleic anhydride modified polypropylene solution with the weight average molecular weight of 25 ten thousand, the melting point of 105-110 ℃ and the acid value of 2 and a curing agent in an inner lamination mode, wherein the anhydrous maleic anhydride modified polypropylene solution contains more than 50 percent of Hexamethylene Diisocyanate (HDI), the hexamethylene diisocyanate is composed of a trimer, the functionality is 3.4, and the mass ratio of the acid modified polypropylene solution to the isocyanate curing agent is 100:2.12, the addition of the acid anhydride group-containing compound was 0.3 parts by mass relative to the acid-modified polypropylene.

The resulting solution-type mixture was applied to the corrosion-treated metal surface of a composite film of the composite outer base resin, and dried to form an inner adhesive layer having a thickness of 2. Mu.m, and then thermally compounded with the adhesive surface of 40. Mu.m, at 120℃and cured at 50℃for 7 days, to form a composite product of the outer base resin layer (25 μm)/outer adhesive layer (3 μm)/intermediate metal layer/inner adhesive layer/inner heat-fusible resin layer (40 μm). The adhesive surface of the 3-layer heat-fusible resin film in contact with the inner adhesive layer was subjected to corona treatment in advance.

As is clear from the results in table 1 below, the metal composite film of the composite product was stored in an electrolyte containing 1000ppm of water at 85 ℃ for 14 days, and the peel strength of the electrolyte was 13.89N, and the retention rate of the peel strength was 92%, so that the metal composite film of this example was excellent in electrolyte resistance.

Example 4

The inner adhesive layer is formed by laminating an anhydrous maleic anhydride modified polypropylene solution with the weight average molecular weight of 25 ten thousand, the melting point of 110-115 ℃ and the acid value of 2 and a curing agent in an inner lamination mode, wherein the anhydrous maleic anhydride modified polypropylene solution contains more than 50 percent of Hexamethylene Diisocyanate (HDI), the hexamethylene diisocyanate is composed of a trimer, the functionality is 3.4, and the mass ratio of the acid modified polypropylene solution to the isocyanate curing agent is 100:2.12, the addition of the acid anhydride group-containing compound was 0.3 parts by mass relative to the acid-modified polypropylene.

As is clear from the results in table 1 below, the metal composite film of the composite product was stored in an electrolyte containing 1000ppm of water at 85 ℃ for 14 days, the electrolyte resistance was 14.77N, and the retention rate of the peel strength was 98%, and therefore the metal composite film of the present example was excellent in electrolyte resistance.

Example 5

The inner adhesive layer is formed by laminating an anhydrous maleic anhydride modified polypropylene solution with the weight average molecular weight of 25 ten thousand, the melting point of 120-130 ℃ and the acid value of 2 and a curing agent in an inner lamination mode, wherein the anhydrous maleic anhydride modified polypropylene solution contains more than 50 percent of Hexamethylene Diisocyanate (HDI), the hexamethylene diisocyanate is composed of a trimer, the functionality is 3.4, and the mass ratio of the acid modified polypropylene solution to the isocyanate curing agent is 100:2.12, the addition of the acid anhydride group-containing compound was 0.3 parts by mass relative to the acid-modified polypropylene.

The resulting solution-type mixture was applied to the corrosion-treated metal surface of a composite film of the composite outer base resin, and dried to form an inner adhesive layer having a thickness of 2. Mu.m, and then thermally compounded with the adhesive surface of the 40. Mu.m heat-sealing resin at 130℃and cured at 50℃for 7 days, to form a composite product of the outer base resin layer (25 μm)/the outer adhesive layer (3 μm)/the intermediate metal layer/the inner adhesive layer/the heat-sealing resin layer (40 μm). The adhesive surface of the 3-layer heat-fusible resin film in contact with the inner adhesive layer was subjected to corona treatment in advance.

As is clear from the results in table 1 below, the metal composite film of the composite product was stored in an electrolyte containing 1000ppm of water at 85 ℃ for 14 days, and the peel strength of the electrolyte was 14.07N, and the retention rate of the peel strength was 87%, so that the metal composite film of this example was excellent in electrolyte resistance.

Example 6

The inner adhesive layer is formed by laminating an anhydrous maleic anhydride modified polypropylene solution with the weight average molecular weight of 25 ten thousand and the melting point of 80-90 ℃ and the acid value of 2 and a curing agent which are epoxy curing agents, wherein one or 2 of bisphenol A epoxy resin, bisphenol F epoxy resin and phenolic epoxy resin can be selected, the epoxy value of the epoxy resin is 0.2mol/100g-2.0mol/100g, the epoxy curing agent is added between 2-15 parts by weight relative to the acid modified polypropylene, and the mass ratio of the acid modified polypropylene solution to the epoxy curing agent is preferably 100:2, the accelerator is preferably amine, and the mass ratio of the acid modified polypropylene solution to the amine accelerator is preferably 100:0.33, the addition of the acid anhydride group-containing compound was 0.15 parts by mass relative to the acid-modified polypropylene.

As is clear from the results in table 1 below, the metal composite film of the composite product was stored in an electrolyte containing 1000ppm of water at 85 ℃ for 14 days, and the peel strength of the electrolyte was 15.82N, and the maintenance rate of the peel strength was 102%, so that the metal composite film of this example was excellent in electrolyte resistance.

Example 7

The inner adhesive layer is formed by laminating an anhydrous maleic anhydride modified polypropylene solution with the weight average molecular weight of 25 ten thousand, the melting point of 80-90 ℃ and the acid value of 2 and a curing agent which are epoxy curing agents, wherein one or 2 of bisphenol A epoxy resin, bisphenol F epoxy resin and phenolic epoxy resin can be selected. The epoxy value is between 0.2mol/100g and 2.0mol/100g, the epoxy curing agent is between 2 and 15 parts by weight relative to the acid modified polypropylene, and the mass ratio of the acid modified polypropylene solution to the epoxy curing agent is preferably 100:2, the accelerator is preferably amine, and the mass ratio of the acid modified polypropylene solution to the amine accelerator is preferably 100:0.33, the addition of the acid anhydride group-containing compound was 0.3 parts by mass relative to the acid-modified polypropylene.

As is clear from the results in table 1 below, the metal composite film of the composite product was stored in an electrolyte containing 1000ppm of water at 85 ℃ for 14 days, and the peel strength of the electrolyte was 15.83N, and the maintenance rate of the peel strength was 102%, so that the metal composite film of this example was excellent in electrolyte resistance.

Example 8

The inner adhesive layer is formed by laminating an anhydrous maleic anhydride modified polypropylene solution with the weight average molecular weight of 25 ten thousand, the melting point of 80-90 ℃ and the acid value of 2 and a curing agent which are epoxy curing agents, wherein one or 2 of bisphenol A epoxy resin, bisphenol F epoxy resin and phenolic epoxy resin can be selected. The epoxy value is between 0.2mol/100g and 2.0mol/100g, the epoxy curing agent is between 2 and 15 parts by weight relative to the acid modified polypropylene, and the mass ratio of the acid modified polypropylene solution to the epoxy curing agent is preferably 100:2, the accelerator is preferably amine, and the mass ratio of the acid modified polypropylene solution to the amine accelerator is preferably 100:0.33, the addition of the acid anhydride group-containing compound was 0.45 parts by mass with respect to the acid-modified polypropylene.

As is clear from the results in table 1 below, the metal composite film of the composite product was stored in an electrolyte containing 1000ppm of water at 85 ℃ for 14 days, and the peel strength of the electrolyte was 15.24N, and the retention rate of the peel strength was 90%, so that the metal composite film of this example was excellent in electrolyte resistance.

Example 9

The inner adhesive layer is formed by laminating an anhydrous maleic anhydride modified polypropylene solution with weight average molecular weight of 25 ten thousand, melting point of 105-110 ℃ and acid value of 2 and a curing agent which are epoxy curing agents, wherein one or 2 of bisphenol A epoxy resin, bisphenol F epoxy resin and phenolic epoxy resin can be selected. The epoxy value is between 0.2mol/100g and 2.0mol/100g, the epoxy curing agent is between 2 and 15 parts by weight relative to the acid modified polypropylene, and the mass ratio of the acid modified polypropylene solution to the epoxy curing agent is preferably 100:2, the accelerator is preferably amine, and the mass ratio of the acid modified polypropylene solution to the amine accelerator is preferably 100:0.33, the addition of the acid anhydride group-containing compound was 0.3 parts by mass relative to the acid-modified polypropylene.

As is clear from the results in table 1 below, the metal composite film of the composite product was stored in an electrolyte containing 1000ppm of water at 85 ℃ for 14 days, and the peel strength of the electrolyte was 14.94N, and the retention rate of the peel strength was 97%, so that the metal composite film of this example was excellent in electrolyte resistance.

Example 10

The inner adhesive layer is formed by laminating an anhydrous maleic anhydride modified polypropylene solution with the weight average molecular weight of 25 ten thousand, the melting point of 110-115 ℃ and the acid value of 2 and a curing agent which are epoxy curing agents, wherein one or 2 of bisphenol A epoxy resin, bisphenol F epoxy resin and phenolic epoxy resin can be selected. The epoxy value is between 0.2mol/100g and 2.0mol/100g, the epoxy curing agent is between 2 and 15 parts by weight relative to the acid modified polypropylene, and the mass ratio of the acid modified polypropylene solution to the epoxy curing agent is preferably 100:2, the accelerator is preferably amine, and the mass ratio of the acid modified polypropylene solution to the amine accelerator is preferably 100:0.33, the addition of the acid anhydride group-containing compound was 0.3 parts by mass relative to the acid-modified polypropylene.

As is clear from the results in table 1 below, the metal composite film of the composite product was stored in an electrolyte containing 1000ppm of water at 85 ℃ for 14 days, and the peel strength of the electrolyte was 15.78N, and the retention rate of the peel strength was 96%, so that the metal composite film of this example was excellent in electrolyte resistance.

Example 11

The inner adhesive layer is formed by laminating an anhydrous maleic anhydride modified polypropylene solution with the weight average molecular weight of 25 ten thousand, the melting point of 120-130 ℃ and the acid value of 2 and a curing agent which are epoxy curing agents, wherein one or 2 of bisphenol A epoxy resin, bisphenol F epoxy resin and phenolic epoxy resin can be selected. The epoxy value is between 0.2mol/100g and 2.0mol/100g, the epoxy curing agent is between 2 and 15 parts by weight relative to the acid modified polypropylene, and the mass ratio of the acid modified polypropylene solution to the epoxy curing agent is preferably 100:2, the accelerator is preferably amine, and the mass ratio of the acid modified polypropylene solution to the amine accelerator is preferably 100:0.33, the addition of the acid anhydride group-containing compound was 0.3 parts by mass relative to the acid-modified polypropylene.

As is clear from the results in table 1 below, the metal composite film of the composite product was stored in an electrolyte containing 1000ppm of water at 85 ℃ for 14 days, and the peel strength of the electrolyte was 16.48N, and the maintenance rate of the peel strength was 99%, so that the metal composite film of this example was excellent in electrolyte resistance.

Comparative example 1

The inner adhesive layer is formed by laminating an anhydrous maleic anhydride modified polypropylene solution with a weight average molecular weight of 25 ten thousand, a melting point of 75 ℃ and an acid value of 2 and a curing agent in an inner lamination manner, wherein the anhydrous maleic anhydride modified polypropylene solution contains more than 50 percent of Hexamethylene Diisocyanate (HDI), the hexamethylene diisocyanate is composed of a trimer, the functionality is 3.4, and the mass ratio of the acid modified polypropylene solution to the isocyanate curing agent is 100:3.11, the addition of the acid anhydride group-containing compound was 0.4 parts by mass relative to the acid-modified polypropylene.

The resulting solution-type mixture was applied to the corrosion-treated metal surface of a composite film of the composite outer base resin, and dried to form an inner adhesive layer having a thickness of 2. Mu.m, and then thermally compounded with the adhesive surface of 40. Mu.m, heat-welded resin at 90℃and cured at 50℃for 7 days, to form a composite product of the outer base resin layer (25 μm)/the outer adhesive layer (3 μm)/the intermediate metal layer/the inner adhesive layer/the heat-welded resin layer (40 μm). The adhesive surface of the 3-layer heat-fusible resin film in contact with the inner adhesive layer was subjected to corona treatment in advance.

From the results shown in Table 1 below, it was found that the metal composite film of the composite product had a low electrolyte resistance in this comparative example because the metal composite film was stored in an electrolyte containing 1000ppm of water at 85℃for 14 days, the electrolyte resistance had a peel strength of 5.32N, and the retention rate of the peel strength was 32%.

Comparative example 2

The inner adhesive layer is formed by laminating an anhydrous maleic anhydride modified polypropylene solution with the weight average molecular weight of 25 ten thousand, the melting point of 80-90 ℃ and the acid value of 2 and a curing agent in an inner lamination mode, wherein the anhydrous maleic anhydride modified polypropylene solution contains more than 50 percent of Hexamethylene Diisocyanate (HDI), the hexamethylene diisocyanate is composed of a trimer, the functionality is 3.4, and the mass ratio of the acid modified polypropylene solution to the isocyanate curing agent is 100:2.12, no anhydride group-containing compound was added.

From the results shown in Table 1 below, it was found that the metal composite film of the composite product had a peel strength of 6.1N and a retention rate of 39% in an electrolyte containing 1000ppm of water at 85℃for 14 days, and therefore the electrolyte resistance of the metal composite film of the comparative example was low.

Comparative example 3

The inner adhesive layer is formed by laminating an anhydrous maleic anhydride modified polypropylene solution with the weight average molecular weight of 25 ten thousand, the melting point of 80-90 ℃ and the acid value of 2 and a curing agent in an inner lamination mode, wherein the anhydrous maleic anhydride modified polypropylene solution contains more than 50 percent of Hexamethylene Diisocyanate (HDI), the hexamethylene diisocyanate is composed of a trimer, the functionality is 3.4, and the mass ratio of the acid modified polypropylene solution to the isocyanate curing agent is 100:2.12 the addition of the acid anhydride group-containing compound was 0.7 parts by mass relative to the acid-modified polypropylene.

From the results shown in Table 1 below, it was found that the metal composite film of the composite product had a peel strength of 6.25N and a retention rate of the peel strength of 44% in an electrolyte containing 1000ppm of water at 85℃for 14 days, and therefore the metal composite film of the comparative example had a low electrolyte resistance.

Comparative example 4

The inner adhesive layer is formed by laminating an anhydrous maleic anhydride modified polypropylene solution with the weight average molecular weight of 25 ten thousand, the melting point of 80-90 ℃ and the acid value of 2 and a curing agent which are epoxy curing agents, wherein one or 2 of bisphenol A epoxy resin, bisphenol F epoxy resin and phenolic epoxy resin can be selected. The epoxy value is between 0.2mol/100g and 2.0mol/100g, the epoxy curing agent is between 2 and 15 parts by weight relative to the acid modified polypropylene, and the mass ratio of the acid modified polypropylene solution to the epoxy curing agent is preferably 100:2, the accelerator is preferably amine, and the mass ratio of the acid modified polypropylene solution to the amine accelerator is preferably 100:0.33, without addition of an acid anhydride group-containing compound.

From the results shown in Table 1 below, it was found that the metal composite film of the composite product had a peel strength of 5.75N against an electrolyte and a retention rate of 48% when stored in an electrolyte containing 1000ppm of water at 85℃for 14 days, and therefore the metal composite film of the comparative example had a low electrolyte resistance.

Comparative example 5

The inner adhesive layer is formed by laminating an anhydrous maleic anhydride modified polypropylene solution with the weight average molecular weight of 25 ten thousand, the melting point of 80-90 ℃ and the acid value of 2 and a curing agent which are epoxy curing agents, wherein one or 2 of bisphenol A epoxy resin, bisphenol F epoxy resin and phenolic epoxy resin can be selected. The epoxy value is between 0.2mol/100g and 2.0mol/100g, the epoxy curing agent is between 2 and 15 parts by weight relative to the acid modified polypropylene, and the mass ratio of the acid modified polypropylene solution to the epoxy curing agent is preferably 100:2, the accelerator is preferably amine, and the mass ratio of the acid modified polypropylene solution to the amine accelerator is preferably 100:0.07, the addition of the acid anhydride group-containing compound was 0.45 parts by mass with respect to the acid-modified polypropylene.

From the results shown in Table 1 below, it was found that the initial peel strength of the metal composite film of the composite product was reduced, and the initial peel strength was 8.38N, which is half that of the other examples.

Comparative example 6

The inner adhesive layer is formed by laminating an anhydrous maleic anhydride modified polypropylene solution with the weight average molecular weight of 25 ten thousand, the melting point of 80-90 ℃ and the acid value of 2 and a curing agent which are epoxy curing agents, wherein one or 2 of bisphenol A epoxy resin, bisphenol F epoxy resin and phenolic epoxy resin can be selected. The epoxy value is between 0.2mol/100g and 2.0mol/100g, the epoxy curing agent is between 2 and 15 parts by weight relative to the acid modified polypropylene, and the mass ratio of the acid modified polypropylene solution to the epoxy curing agent is preferably 100:2, no amine accelerator and no anhydride group-containing compound are added.

From the results shown in Table 1 below, it was found that the initial peel strength of the metal composite film of the composite product was lowered, and the initial peel strength was 7.49N, which is half that of the other examples.

TABLE 1

The above description of the common general knowledge will not be described in detail, as will be appreciated by those skilled in the art.

The foregoing description of the embodiments of the invention is not intended to be limiting, but rather is intended to cover all modifications, equivalents, alternatives, and improvements that fall within the spirit and scope of the invention. The technical scope of the present invention is not limited to the description, but must be determined according to the scope of claims.

Claims

1. A metal composite film, comprising:

a metal layer, an inner adhesive layer, a heat-welding resin layer, an outer adhesive layer, and an outer layer;

the outer layer is arranged on one side of the metal layer, the thermal welding resin layer is arranged on the other side of the metal layer, the inner layer bonding layer is arranged between the metal layer and the thermal welding resin layer, and the outer layer bonding layer is arranged between the outer layer and the metal layer;

The inner layer adhesive layer contains acid modified polypropylene, epoxy curing agent, amine accelerator, bridging agent containing anhydride group compound, or contains acid modified polypropylene, isocyanate curing agent, bridging agent containing anhydride group compound.

2. The metal composite film according to claim 1, wherein the inner adhesive layer contains acid-modified polypropylene, an isocyanate curing agent, and a bridging agent containing an anhydride group-containing compound.

3. The metal composite film of claim 1, wherein the bridging agent has at least 1 anhydride, the anhydride comprising one or more of a linear anhydride, an aromatic anhydride, and a cycloaliphatic anhydride.

4. The metal composite film according to claim 1, wherein the bridging agent has 4 to 20 carbon atoms and the degree of unsaturation of the olefin is 1 or more.

5. The metal composite film according to claim 1, wherein the bridging agent contains a carbon-carbon double bond and a methyl group.

6. The metal composite film according to claim 1, wherein the acid value of the bridging agent is 100mgKOH/g to 800mgKOH/g.

7. The metal composite film according to claim 1, wherein the acid-modified polypropylene contains a polypropylene resin modified by a grafting treatment with a carboxylic acid or an anhydride thereof, and has an acid value of 1 to 5, a melting point of 70 to 130 ℃ and a weight average molecular weight of 10 to 25 ten thousand.

8. The metal composite film according to claim 1, wherein the bridging agent is 10 to 100% by weight of the epoxy curing agent.

9. The metal composite film according to claim 1, wherein the amine accelerator comprises one or more of aliphatic amines and aromatic amine curing agents, and the weight part of the amine accelerator relative to the acid-modified polypropylene is 0.02 to 2.

10. The metal composite film according to claim 1, wherein the amine accelerator comprises an aromatic amine curing agent which is a secondary amine, a tertiary amine aromatic amine compound, and N, N-dimethylbenzylamine, and the amine accelerator is 0.02 to 2 parts by weight relative to the acid-modified polypropylene.

11. The metal composite membrane of claim 1, wherein the amine promoter comprises N, N-dimethylbenzylamine.

12. The metal composite film according to claim 1, wherein the epoxy curing agent is selected from the group consisting of bisphenol a epoxy resin, bisphenol F epoxy resin, phenol novolac epoxy, o-cresol novolac epoxy, triphenol methane epoxy, tetraphenol ethane epoxy, polyphenol glycidyl ether epoxy resin, aliphatic glycidyl ether epoxy resin, and glycidyl ester epoxy resin.

13. The metal composite film according to claim 1, wherein the epoxy-based curing agent is bisphenol a epoxy resin and novolac epoxy resin having an epoxy value of 0.2mol/100g to 2.0mol/100g, and the epoxy-based curing agent is 2 to 15 parts by weight relative to the acid-modified polypropylene.

14. The metal composite film according to claim 1, wherein the isocyanate curing agent contains 50% or more of one or more of hexamethylene diisocyanate and pentamethylene diisocyanate, and the ratio NCO/COOH of the number of moles of carboxyl groups in the acid-modified polypropylene to the number of moles of isocyanate groups (NCO value) of the isocyanate curing agent is 1.36 to 4.32.