CN113415053B

CN113415053B - Coating type polyamide film suitable for aluminum plastic film and preparation method thereof

Info

Publication number: CN113415053B
Application number: CN202010818197.5A
Authority: CN
Inventors: 刘运锦
Original assignee: Xiamen Changsu Industrial Co Ltd
Current assignee: Xiamen Changsu Industrial Co Ltd
Priority date: 2020-08-14
Filing date: 2020-08-14
Publication date: 2022-07-29
Anticipated expiration: 2040-08-14
Also published as: CN113415053A

Abstract

The invention discloses a coating polyamide film suitable for an aluminum plastic film and a preparation method thereof, wherein the film consists of a coating layer and a substrate layer; the coating layer is formed by coating acrylic acid coating liquid on the surface of the polyamide base material layer; the acrylic coating liquid comprises organic silicon modified acrylic resin, crosslinked PMMA powder and water, wherein the mass ratio of the organic silicon modified acrylic resin to the crosslinked PMMA powder is (8-10): 3-5; the substrate layer is a three-layer biaxially oriented polyamide film and comprises the components of polyamide, copolyamide, dendritic polyamidoamine and black pigment. The production process of the film is simple, and the material is green and environment-friendly; low friction coefficient, low glossiness and good light-shielding performance. Meanwhile, after the film is compounded with aluminum foil and PE, the film has good pit punching performance, no edge warping occurs after pit punching, and the film has good electrolyte resistance, is particularly suitable for aluminum-plastic composite film flexible packaging, and has good market application prospect.

Description

Coating type polyamide film suitable for aluminum plastic film and preparation method thereof

Technical Field

The invention belongs to the technical field of packaging materials, and particularly relates to a coating type polyamide film suitable for an aluminum plastic film and a preparation method thereof.

Background

The lithium ion battery is composed of a liquid, gel or polymer electrolyte, a positive electrode, a negative electrode active material, and an exterior package. The used outer package material is an aluminum-plastic composite material, and the typical structure of the outer package material is as follows: PET/PA/AL/CPP, and bonding the layers by special glue. The aluminum-plastic composite film (aluminum-plastic film) is a key material for packaging the soft package aluminum battery, the single lithium battery is sealed by the aluminum-plastic film after being assembled to form a battery, and the aluminum-plastic film plays a role in protecting contents. The aluminum plastic film is taken as the key link with the highest barrier in the lithium battery industry chain, and the global aluminum plastic film market is monopolized by a small number of Japan enterprises all the time and occupies about 75 percent of the global market share. At present, domestic enterprises become mature through years of accumulation technology, large-scale production is gradually realized, and the domestic aluminum-plastic composite film has extremely high market prospect in the future.

The outer layer of the aluminum-plastic composite film is compounded with the PET layer, so that the phenomenon that electrolyte drops on the surface of the aluminum-plastic film in the lithium battery packaging process to cause the aluminum-plastic film (such as PA (polyamide) cannot resist electrolyte) to be corroded by hydrofluoric acid in the electrolyte is mainly prevented.

The PA layer plays a main mechanical supporting role in the whole aluminum-plastic composite film, and the problems of deep punching depth, edge warping and the like of the lithium battery outer package in the one-step cold punching process are determined.

For the black aluminum-plastic composite film, a layer of black matte oil needs to be coated on the surface of an aluminum layer connected with an adhesive layer, in the actual production process, the black matte oil coating process can cause about 30-40% of aluminum-plastic film loss, and meanwhile, the shading degree is difficult to ensure, so that certain risk is brought to the quality stability of the aluminum-plastic composite film.

Disclosure of Invention

The invention aims to overcome the defects of the prior art, and provides a coating type polyamide film suitable for an aluminum-plastic film and a preparation method thereof.

One of the technical schemes adopted by the invention for solving the technical problems is as follows: the coating type polyamide film suitable for the aluminum plastic film is provided, and consists of a coating layer and a base material layer;

the coating layer is formed by coating acrylic acid coating liquid on the surface of the polyamide base material layer; the acrylic coating liquid comprises organic silicon modified acrylic resin, crosslinked PMMA powder and water, wherein the mass ratio of the organic silicon modified acrylic resin to the crosslinked PMMA powder is (8-10): 3-5;

The substrate layer is a three-layer biaxially oriented polyamide film and comprises a first substrate layer, a second substrate layer and a third substrate layer from top to bottom in sequence, and the first substrate layer is compounded with the coating layer; the components of the substrate layer comprise polyamide, copolyamide, dendritic polyamidoamine and black pigment.

In a preferred embodiment of the invention, the first substrate layer comprises, by mass, 86-94.5 parts of copolyamide, 5-20 parts of dendritic polyamidoamine, 0.5-2 parts of black pigment, 0-1 part of opening agent and 0-1 part of slipping agent.

In a preferred embodiment of the invention, the second substrate layer comprises, by mass, 70 to 89.2 parts of polyamide, 10 to 25 parts of copolyamide, 0.5 to 3 parts of dendritic polyamidoamine, and 0.5 to 2 parts of black pigment.

In a preferred embodiment of the invention, the third substrate layer comprises, by mass, 96-99.5 parts of polyamide, 0.5-2 parts of black pigment, 0-1 part of an opening agent, and 0-1 part of a slipping agent.

In a preferred embodiment of the present invention, the total thickness of the substrate layer is 10 to 30 μm, and the thickness of the coating layer is 0.5 to 2 μm.

The second technical scheme adopted by the invention for solving the technical problems is as follows: the preparation method of the coating type polyamide film suitable for the aluminum plastic film comprises the following steps:

1) Preparation of acrylic coating liquid:

dissolving organic silicon modified acrylic resin in water, heating and stirring at 60-80 ℃ until the organic silicon modified acrylic resin is completely dissolved, and then cooling to room temperature to obtain an acrylic acid solution with the concentration of 8-10 wt% for later use;

adding 3-5 wt% of crosslinked PMMA powder into the acrylic acid solution, stirring and ultrasonically treating until the crosslinked PMMA powder is uniformly dispersed, and preparing an acrylic acid coating liquid;

2) preparing a base material layer:

blending each layer of components in the base material layer according to respective proportion, and performing melt blending, extrusion, granulation and drying by using a double-screw extruder to respectively obtain a first master batch, a second master batch and a third master batch for later use; wherein the extrusion temperature of the first master batch is controlled to be 140-180 ℃, and the extrusion temperature of the second master batch and the third master batch is controlled to be 180-260 ℃;

secondly, putting the first master batch into a first extruder to manufacture a first substrate layer, and controlling the temperature of the extruder and the temperature of a T-shaped die head of the extruder to be 140-180 ℃;

putting the second master batch into a second extruder to manufacture a second substrate layer; putting the third master batches into a third extruder to manufacture a third base material layer; the temperature of the extruder and the T-shaped die head is controlled to be 220-240 ℃;

3) Assembling:

extruding and quenching the master batches of the layers by using a LISIM synchronous stretching method, humidifying and cleaning the surface of the cast sheet by using a hot water tank at 60-80 ℃, removing the moisture on the surface of the cast sheet by using hot air, coating the acrylic coating liquid prepared in the step 2) on the surface of the first substrate layer, and then performing bidirectional stretching at the stretching temperature of 50-100 ℃, the setting temperature of 120-180 ℃ and the stretching magnification of 3.0-3.8 to obtain the coated polyamide film suitable for the aluminum plastic film.

Compared with the background technology, the technical scheme has the following advantages:

1. the acrylic acid coating liquid has a very low friction coefficient, so that the coating has a relatively high wear resistance; the PMMA is present, so that the scratch resistance of the coating is improved, and the glossiness of the coating is reduced; meanwhile, the coating has better electrolyte resistance;

2. the polyamidoamine in the first base material layer has a large number of active groups, and can react with carboxyl and hydroxyl in the acrylic coating liquid, so that the bonding strength of the coating can be improved; the design of adopting ternary copolymer polyamide as a first base material layer is to reduce the processing temperature and keep the active group of polyamide amine as much as possible;

3. In the components of the base material layer, the nano effect of the polyamide amine and the coordination and toughening of the copolymerized polyamide provide excellent pit resistance and edge warping resistance for the whole film;

4. the film disclosed by the invention is simple in production process, environment-friendly in material, stable in size and excellent in comprehensive performance, can be well compounded with an aluminum-plastic film, reduces the loss of the aluminum-plastic film, reduces the production process of a downstream aluminum-plastic composite film and saves the cost.

Drawings

FIG. 1 is a layer structure diagram of a film of example 1.

Wherein, 1-coating layer, 2-base material layer, 21-first base material layer, 22-second base material layer, 23-third base material layer.

Detailed Description

It should be noted that the terms "upper", "lower", and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and the terms "first", "second", and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance. Those who do not specify a specific technique or condition, according to the techniques or conditions described in the literature in the art or according to the specification of the product, and those who do not specify a reagent or apparatus to be used, are all conventional products commercially available.

Example 1

The coating type polyamide film suitable for the aluminum plastic film comprises a coating layer 1 and a base material layer 2;

the coating layer 1 is formed by coating acrylic acid coating liquid on the surface of the polyamide base material layer 2; the acrylic coating liquid is prepared from acrylic resin modified by organic silicon, 4 wt% of PMMA and water, and the solid content of the acrylic resin is 9 wt%;

the thickness of the substrate layer 2 is 25 micrometers, the substrate layer is a three-layer biaxially oriented polyamide film, and the substrate layer comprises a first substrate layer 21, a second substrate layer 22 and a third substrate layer 23 from top to bottom in sequence, wherein the first substrate layer 21 is compounded with the coating layer 1.

The preparation method of the coating type polyamide film suitable for the aluminum plastic film comprises the following steps:

1) preparation of acrylic acid coating solution:

dissolving organic silicon modified acrylic resin in water, heating and stirring at 60-80 ℃ until the organic silicon modified acrylic resin is completely dissolved, and then cooling to room temperature to obtain an acrylic acid solution with the concentration of 8-10 wt% for later use; adding 3-5 wt% of crosslinked PMMA powder into the acrylic acid solution, adding water to adjust the solid content to 9 wt%, stirring and performing ultrasonic treatment until the solid content is uniformly dispersed to prepare an acrylic acid coating liquid;

2) preparation of the base material layer 2:

Mixing the components of each layer in the substrate layer 2 according to respective proportions, which are as follows:

first substrate layer 21 composition (in mass percent): 83% of terpolymer of nylon 6/nylon 66/nylon 1212, 15% of PAMAM4.0, 1% of carbon black, 0.5% of silicon dioxide and 0.5% of ethylene bis stearamide;

second substrate layer 22 components (in mass percent): nylon 683%, nylon 6/nylon 66 binary copolymer 15%, PAMAM4.0 generation 1%, carbon black 1%;

third substrate layer 23 component (in mass percent): nylon 698%, carbon black 1%, silicon dioxide 0.5%, ethylene bisstearamide 0.5%.

Carrying out melt blending, extrusion, granulation and drying by a double-screw extruder to respectively obtain a first master batch, a second master batch and a third master batch for later use; wherein the extrusion temperature of the first master batch is controlled to be 140-180 ℃, and the extrusion temperature of the second master batch and the third master batch is controlled to be 180-260 ℃;

secondly, putting the first master batch into a first extruder to manufacture a first substrate layer 21, and controlling the temperature of the extruder and the temperature of a T-shaped die head of the extruder to be 140-180 ℃;

putting the second master batch into a second extruder to manufacture a second substrate layer 22; putting the third master batches into a third extruder to manufacture a third substrate layer 23; the temperature of the extruder and the T-shaped die head is controlled to be 220-240 ℃;

3) Assembling:

extruding and quenching the master batches of the layers by using a LISIM synchronous stretching method, humidifying and cleaning the surface of the cast sheet by using a hot water tank at 60-80 ℃, removing the moisture on the surface of the cast sheet by using hot air, coating the acrylic coating liquid prepared in the step 2) on the surface of the first substrate layer 21, and then performing bidirectional stretching at the stretching temperature of 50-100 ℃, the setting temperature of 120-180 ℃ and the stretching magnification of 3.0 x 3.0-3.8 x 3.8 to obtain the coated polyamide film suitable for the aluminum plastic film.

Example 2

Example 2 differs from example 1 in that:

the acrylic coating liquid is prepared from organosilicon modified acrylic resin, 5 wt% of PMMA and water, and the solid content of the acrylic coating liquid is 10 wt%;

first substrate layer composition (in mass percent): 76% of nylon 6/nylon 66/nylon 1212 terpolymer, 4.0 PAMAM 20%, 2% of carbon black, 1% of silicon dioxide and 1% of ethylene bisstearamide;

second substrate layer composition (in mass percent): nylon 670%, nylon 6/nylon 66 binary copolymer 25%, PAMAM4.0 generation 3%, carbon black 2%;

third substrate layer composition (in mass percent): nylon 694%, carbon black 2%, silicon dioxide 1%, ethylene bisstearamide 1%.

Example 3

Example 3 differs from example 1 in that:

the acrylic coating liquid is prepared from organosilicon modified acrylic resin, 4 wt% of PMMA and water, and the solid content of the acrylic coating liquid is 9 wt%;

first substrate layer composition (in mass percent): 94.1 percent of terpolymer of nylon 6/nylon 66/nylon 1212, 4.0 generation 5 percent of PAMAM, 0.5 percent of carbon black, 0.2 percent of silicon dioxide and 0.2 percent of ethylene bis stearamide;

second substrate layer composition (in mass percent): nylon 689%, nylon 6/nylon 66 binary copolymer 10%, PAMAM4.0 generation 0.5%, carbon black 0.5%;

third substrate layer composition (in mass percent): nylon 698.5%, carbon black 0.5%, silicon dioxide 0.5%, ethylene bisstearamide 0.5%.

Example 4

Example 4 differs from example 1 in that:

first substrate layer composition (in mass percent): 83% of nylon 6/nylon 66/nylon 1010 terpolymer, 15% of PAMAM2.0, 1% of organic melanin, 0.5% of silicon dioxide and 0.5% of ethylene bis stearamide;

second substrate layer composition (in mass percent): nylon 683%, nylon 6/nylon 12 binary copolymer 15%, PAMAM2.0 generation 1%, and organic melanin 1%;

Third substrate layer composition (in mass percent): nylon 698%, organic melanin 1%, silicon dioxide 0.5%, ethylene bisstearamide 0.5%.

Comparative example 1

Comparative example 1 a commercially available biaxially oriented nylon film having a thickness of 25 μm was used.

Comparative example 2

A coating type polyamide film of comparative example 2 was a coating layer and a polyamide base material layer in this order from the top.

The acrylic acid coating liquid is prepared from organosilicon modified acrylic acid resin and water, and the solid content of the acrylic acid coating liquid is 9 wt%;

the polyamide substrate layer is a biaxially oriented nylon film which is commonly used in the market and has the thickness of 25 mu m.

The preparation method and coating method of the acrylic coating liquid are the same as those of example 1.

Comparative example 3

A coating type polyamide film of comparative example 3, which comprises a coating layer and a polyamide base material layer in this order from top to bottom;

Comparative example 4

A coating type polyamide film of comparative example 4, which comprises a coating layer and a polyamide base material layer in this order from the top down;

the polyamide substrate layer from top to bottom include first substrate layer, second substrate layer and third substrate layer, wherein:

first substrate layer composition (in mass percent): nylon 683%, PAMAM4.0 generation 15%, carbon black 1%, silicon dioxide 0.5%, ethylene bis stearamide 0.5%;

second substrate layer composition (in mass percent): nylon 683%, nylon 6/nylon 66 binary copolymer 15%, PAMAM4.0 generation 1%, carbon black 1%;

third substrate layer composition (in mass percent): nylon 698%, carbon black 1%, silicon dioxide 0.5%, ethylene bisstearamide 0.5%.

The preparation method of the acrylic coating liquid, the preparation method of the base material layer and the coating method are the same as those of the example 1, except that: the basic temperature of the first master batch in the first base material layer is 180-240 ℃ (180 ℃ is excluded).

Comparative example 5

A coating type polyamide film of comparative example 5, which comprises a coating layer and a polyamide base material layer in this order from the top down;

first substrate layer composition (in mass percent): 83% of terpolymer of nylon 6/nylon 66/nylon 1212, 15% of PAMAM4.0, 1% of carbon black, 0.5% of silicon dioxide and 0.5% of ethylene bis stearamide;

second substrate layer composition (in mass percent): nylon 698%, PAMAM4.0 generation 1%, carbon black 1%;

third substrate layer composition (in mass percent): nylon 698%, carbon black 1%, silicon dioxide 0.5%, ethylene bis stearamide 0.5%;

the preparation method of the acrylic coating liquid, the preparation method of the polyamide base material layer and the coating method are the same as those of the example 1.

Comparative example 6

A coating type polyamide film of comparative example 6, which comprises a coating layer and a polyamide base material layer in this order from the top down;

Second substrate layer composition (in mass percent): 684% of nylon, 15% of nylon 6/nylon 66 binary copolymer and 1% of carbon black;

The films prepared in the above examples and comparative examples were subjected to performance tests, and the test evaluation results are shown in table 1:

TABLE 1 film Performance test evaluation Table

And (3) testing the depth of a punched hole: the PA/AL/CPP composite films were prepared from the polyamide films of examples and comparative examples, and the PA/AL/CPP composite films were held by a punching die used in a lithium ion battery aluminum-plastic packaging film factory, and the films were tested using punching heads of different depths until the films were punched.

Punching a pit and warping: the PA/AL/CPP composite films were prepared from the polyamide films of examples and comparative examples, and the PA/AL/CPP composite films were held by a pit punching mold used in a lithium ion battery aluminum-plastic packaging film factory, with a pit punching depth of 5.5mm, and edge warping was observed. No edge warping, indicated by "∘"; delta is used for raising edges.

Electrolyte resistance performance test: the biaxially oriented polyamide films prepared in the above examples and the films in comparative examples were dropped with the same amount of an electrolyte using a commercially available lithium battery electrolyte, and left at 25 ℃ RH 50% for 2 hours, and then the electrolyte was wiped off with paper gently to observe the corrosion of the surface. The resistance to electrolyte corrosion is indicated by ". smallcircle", and the resistance to electrolyte corrosion is indicated by ". DELTA".

As can be seen from table 1, the coating polyamide films of examples 1 to 4 of the present invention have a small friction coefficient, a low gloss, and a good light-shielding property, and at the same time, the film has a good pit punching property after being compounded with aluminum foil and PE, does not generate edge warping after pit punching, has a good electrolyte resistance, and is particularly suitable for flexible aluminum-plastic composite film packaging.

It will be appreciated by those skilled in the art that the same or similar technical effects as those of the above embodiments can be expected when the technical parameters of the present invention are changed within the following ranges:

the polyamide is one or a combination of more of nylon 6, nylon 66, nylon 612, nylon 610, nylon 12 and nylon 1212.

The polyamide is formed by copolymerizing two or more than two monomers of nylon 6, nylon 66, nylon 11, nylon 12, nylon 1010 and nylon 1212, and the melting point of the copolymerized polyamide is 120-240 ℃.

The dendritic polyamidoamine is one or a combination of more than one of 1.0 generation of PAMAM, 2.0 generation of PAMAM, 3.0 generation of PAMAM, 4.0 generation of PAMAM, 5.0 generation of PAMAM, 6.0 generation of PAMAM, 7.0 generation of PAMAM, 8.0 generation of PAMAM, 9.0 generation of PAMAM and 10.0 generation of PAMAM.

The black pigment is one or a combination of more of carbon black, graphene and organic melanin.

The above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; while the invention has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A coated polyamide film suitable for use in aluminum-plastic films, characterized by: the coating layer and the substrate layer are formed;

The substrate layer is a three-layer biaxially oriented polyamide film and comprises a first substrate layer, a second substrate layer and a third substrate layer from top to bottom in sequence, and the first substrate layer is compounded with the coating layer; the components of the substrate layer comprise polyamide, copolyamide, dendritic polyamidoamine and black pigment;

the first substrate layer comprises 76-94.5 parts of copolyamide, 5-20 parts of dendritic polyamidoamine, 0.5-2 parts of black pigment, 0-1 part of opening agent and 0-1 part of slipping agent in parts by mass; the second substrate layer is composed of, by mass, 70-89.2 parts of polyamide, 10-25 parts of copolyamide, 0.5-3 parts of dendritic polyamidoamine and 0.5-2 parts of black pigment.

2. A coated polyamide film suitable for an aluminum-plastic film according to claim 1, wherein: the third base material layer comprises, by mass, 96-99.5 parts of polyamide, 0.5-2 parts of black pigment, 0-1 part of an opening agent and 0-1 part of a slipping agent.

3. A coated polyamide film suitable for an aluminum-plastic film according to claim 1, wherein: the polyamide is one or a combination of more of nylon 6, nylon 66, nylon 612, nylon 610, nylon 12 and nylon 1212.

4. A coated polyamide film suitable for aluminum plastic films according to claim 1, which comprises: the copolymerized polyamide is formed by copolymerizing two or more than two monomers of nylon 6, nylon 66, nylon 11, nylon 12, nylon 1010 and nylon 1212, and the melting point of the copolymerized polyamide is 120-240 ℃.

5. A coated polyamide film suitable for an aluminum-plastic film according to claim 1, wherein: the dendritic polyamidoamine is one or a combination of more than one of 1.0 generation of PAMAM, 2.0 generation of PAMAM, 3.0 generation of PAMAM, 4.0 generation of PAMAM, 5.0 generation of PAMAM, 6.0 generation of PAMAM, 7.0 generation of PAMAM, 8.0 generation of PAMAM, 9.0 generation of PAMAM and 10.0 generation of PAMAM.

6. A coated polyamide film suitable for an aluminum-plastic film according to claim 1, wherein: the black pigment is one or a combination of carbon black, graphene and organic melanin.

7. A coated polyamide film suitable for an aluminum-plastic film according to claim 1, wherein: the total thickness of the substrate layer is 10-30 mu m, and the thickness of the coating layer is 0.5-2 mu m.

8. The method for preparing a coated polyamide film suitable for an aluminum-plastic film according to any one of claims 1 to 7, wherein: the method comprises the following steps:

1) Preparation of acrylic coating liquid:

2) preparing a base material layer:

3) Assembling:

extruding and quenching the master batches of the layers by using a LISIM synchronous stretching method, humidifying and cleaning the surface of the cast sheet by using a hot water tank at 60-80 ℃, removing the moisture on the surface of the cast sheet by using hot air, coating the acrylic coating liquid prepared in the step 1) on the surface of the first substrate layer, and then performing bidirectional stretching at the stretching temperature of 50-100 ℃, the setting temperature of 120-180 ℃ and the stretching magnification of 3.0-3.8 to obtain the coated polyamide film suitable for the aluminum plastic film.