CN112358637B

CN112358637B - Polyphenylene sulfide film suitable for ultrathin coating and preparation method and application thereof

Info

Publication number: CN112358637B
Application number: CN202011207195.9A
Authority: CN
Inventors: 周贵阳; 金秉宸; 沈金涛; 邓杭军
Original assignee: Zhejiang NHU Co Ltd; Zhejiang NHU Special Materials Co Ltd
Current assignee: Zhejiang NHU Co Ltd; Zhejiang NHU Special Materials Co Ltd
Priority date: 2020-11-03
Filing date: 2020-11-03
Publication date: 2022-06-21
Anticipated expiration: 2040-11-03
Also published as: CN112358637A

Abstract

The invention discloses a polyphenylene sulfide film suitable for an ultrathin coating, and a preparation method and application thereof. The preparation process comprises the following steps: taking polyphenylene sulfide resin without a shedding agent as a raw material, and performing melt extrusion, cooling and shaping to obtain a polyphenylene sulfide sheet; longitudinally stretching the polyphenylene sulfide sheet, and uniformly coating two surfaces of a longitudinally stretched film to prepare a polymer coating; and then carrying out transverse stretching, heat setting, cooling treatment and rolling. The polyphenylene sulfide film suitable for the ultrathin coating disclosed by the invention has the advantages that the surface smoothness is greatly improved, and the surface roughness is less than or equal to 0.08 mu m, so that the uniformity of the thickness of a subsequent coating is ensured, and the polyphenylene sulfide film can be used as a negative current collector of energy storage equipment through further copper plating treatment.

Description

Polyphenylene sulfide film suitable for ultrathin coating and preparation method and application thereof

Technical Field

The invention relates to the field of preparation of polyphenylene sulfide films, in particular to a polyphenylene sulfide film suitable for an ultrathin coating, a preparation method of the film and application of the film in preparation of a negative current collector.

Background

The copper foil is adopted as the negative electrode current collector of the traditional lithium ion battery, but with the development of the lithium battery technology, the high energy density, the light weight and the flexibility of the lithium ion battery become the pursuit direction of people. The copper foil is thinned, so that the light weight of the lithium ion battery can be realized, the energy density is improved, and the cost is reduced, but the thickness of the copper foil is difficult to obtain great reduction due to the limitation of a preparation technology; more importantly, the mechanical strength is reduced after the copper foil is thinned, resulting in a reduction in processability.

In the prior art, a new thinning direction has been proposed, in which copper is plated on a polymer film (such as a polyphenylene sulfide film) as a current collector to improve the energy density of the battery and lighten the battery. However, when the conventional polymer film is stacked and rolled, the polymer film is easy to adhere together due to the existence of surface tension, is difficult to separate, and even cannot be used. In order to prevent the phenomenon, a certain amount of micron-sized (1-3 μm) opening agent is usually added during the production of the film. However, the addition of the micron-sized opening agent can cause the surface of the film to be uneven, and if copper layers with the thickness of only a few microns are directly plated on the two surfaces of the film to form a negative electrode current collector serving as an energy storage device, the thickness of the plated layer can be affected by the raised opening agent and is uneven. The uneven thickness of the plating layer can affect the conductivity and the current carrying capacity of the current collector and finally affect the performance of the battery pole piece.

In order to solve the above problems, the common solution in the prior art is to reduce the particle size of the opening agent, i.e. replace the original micron-sized opening agent with a nano-sized opening agent, and extrude the opening agent by blending with resin. Although the method can introduce the opening agent to the surface of the film, the nano-scale particles simultaneously have the function of a nucleating agent, and can accelerate the crystallization rate of the resin when being melted and blended with the resin, so that the processing is difficult, for example, the crystallization degree is rapidly increased, so that the cast sheet is easy to break, the film is easy to break when being stretched, and the like.

Disclosure of Invention

Aiming at the problems, the invention discloses a polyphenylene sulfide film suitable for an ultrathin coating and a preparation method thereof, wherein the surface smoothness of the polyphenylene sulfide film is greatly improved, and the surface roughness is less than or equal to 0.08 mu m, so that the thickness uniformity of a subsequent ultrathin coating is ensured.

The specific technical scheme is as follows:

a polyphenylene sulfide film suitable for ultrathin plating, comprising: the upper surface and the lower surface of the polyphenylene sulfide film layer are respectively provided with a polymer coating.

According to the invention, a micron-sized opening agent is not used in the process of preparing the polyphenylene sulfide film, and the scheme is replaced by an upper high-molecular polymer coating and a lower high-molecular polymer coating, so that the problem that the unevenness of the film surface caused by the micron-sized opening agent further influences the uneven thickness of a coating layer in the subsequent copper plating process is solved.

Preferably:

the polyphenylene sulfide film layer comprises polyphenylene sulfide resin as raw materials, but does not contain an opening agent.

Preferably, the weight average molecular weight of the polyphenylene sulfide resin is 40000-100000, and the melt flow rate is 20-80 g/10min (obtained by testing according to a GB/T3682 method); further preferably, the weight average molecular weight is 50000-80000, and the melt flow rate is 30-50 g/10 min.

Preferably:

the polymer coating comprises the following raw materials in percentage by weight:

in the invention, the formula of the polymer coating is specially designed for plating an ultrathin copper layer on the surface of polyphenylene sulfide, and polyphenylene sulfide resin and epoxy resin are taken as main bodies. Tests show that if the polyphenylene sulfide resin is used as the main body alone or epoxy resin is replaced by other common high molecular resins such as polyurethane, the roughness of the surface of the prepared polymer coating is increased, and the thickness uniformity of a subsequent copper plating layer is affected.

Preferably, the melt flow rate of the polyphenylene sulfide resin is 3000-4000 g/10min (obtained by referring to GB/T3682 method test). Tests show that the PPS resin with the high flow rate has better slippage, is more beneficial to the air exhaust and uncoiling of the films, reduces the friction coefficient between the films, and is beneficial to solving the problem of coiling adhesion. Further experiments show that if the melt flow rate of the selected polyphenylene sulfide resin is too low, the roughness of the surface of the prepared polymer coating is increased, and the thickness uniformity of a subsequent copper plating layer is affected.

The epoxy resin is selected from water-based epoxy resins, and preferably, the solid content of the water-based epoxy resin is 50-60%. Specifically, it is EPIKOTE 1007-CT-55 manufactured by Hansen Mayer corporation in America.

Preferably, the nano opening agent is selected from one or more of nano copper powder, nano calcium carbonate, nano alumina, nano silica and nano magnesia. More preferably, the nano-opening agent, D90, is 80 to 100 nm. It is found that if the value of D90 of the nano opening agent is too large, the roughness of the surface of the prepared polymer coating is increased, and the thickness uniformity of the subsequent copper plating layer is affected. More preferably, the nano opening agent is selected from nano copper powder with D90-80 nm.

The curing agent is selected from the conventional species in the art, such as dimethylaminopropylamine, polyetherdiamine, triethylenetetramine, and the like.

The organic solvent is required to dissolve the epoxy resin and form a well-dispersed suspension with PPS. And the boiling point is below the cold crystallization temperature of the PPS resin, so that the PPS resin can be completely volatilized in the process of film stretching. If the solvent is not completely volatilized during the stretching step, the heat setting effect is not good. Preferably one or more of ethanol, butyl acetate and isopropanol. Ethanol is more preferred.

The polymer coating is further preferably prepared from the following raw materials in addition to the above preferred raw material types:

tests show that the roughness of the surface of the prepared polymer coating is less than or equal to 0.08 mu m under the preferable types and contents of the raw materials, so that the uniformity of the thickness of a subsequent coating is ensured, and the uniformity is less than 5%.

The invention also discloses a preparation method of the polyphenylene sulfide film suitable for the ultrathin coating, which comprises the following steps:

(1) taking pure polyphenylene sulfide resin as a raw material, and obtaining a polyphenylene sulfide sheet after melt extrusion, cooling and sizing;

(2) longitudinally stretching the polyphenylene sulfide sheet prepared in the step (1), and uniformly coating two surfaces of the longitudinally stretched film to prepare a polymer coating;

(3) and (3) transversely stretching, heat setting and cooling the film coated with the polymer coating and prepared in the step (2), and then rolling.

In the preparation method disclosed by the invention, the time for carrying out the coating process is very critical, and the coating process is selected after longitudinal stretching and before transverse stretching. It has been found through experiments that either advancing the coating process before longitudinal stretching or retarding the coating process after transverse stretching results in a significant increase in roughness and poor planarity of the produced polymer coating.

In the step (1), the method specifically comprises the following steps:

melting polyphenylene sulfide resin, extruding by using a double-screw extruder, cutting into granules after extrusion into granular solid, putting into vacuum for drying, and taking away excessive moisture by controlling introduced dry nitrogen to obtain the film raw material. And then feeding the dried polyphenylene sulfide particles into a double-screw extruder, controlling the temperature of each zone and a die head to be not higher than 280 ℃, melting, then feeding the molten polyphenylene sulfide particles into the die head for extrusion, and chilling the molten polyphenylene sulfide particles to form the sheet with high flatness and low crystallinity.

In the step (2), all raw materials for preparing the polymer coating are blended and uniformly stirred to prepare a polymer solution, the polymer solution is conveyed to a slit of a coating machine through a liquid supply pump of the coating machine, and the solution extruded from the slit is sprayed to two sides of the longitudinally stretched film and is evenly scraped.

Preferably, the ratio of the longitudinal stretching to the transverse stretching is independently controlled to be 3-4.

The invention also discloses a negative current collector which comprises the polyphenylene sulfide film suitable for the ultrathin coating; the ultrathin plating layer is characterized by also comprising copper layers plated on the upper surface and the lower surface of the polyphenylene sulfide film suitable for the ultrathin plating layer respectively.

The copper layer can be prepared by a preparation process which is conventional in the field, such as vapor deposition copper plating.

Preferably, the thickness of the copper layer is 0.5 to 1.5 μm, and more preferably 0.8 to 1.2 μm.

Compared with the prior art, the invention has the following beneficial effects:

the invention discloses a polyphenylene sulfide film suitable for an ultrathin coating, wherein polymer coatings composed of special raw materials are respectively coated on the upper surface and the lower surface of the polyphenylene sulfide film. Meanwhile, the problems that the polymer films are easy to adhere together and not easy to separate when being stacked and rolled are solved. The surface roughness of the polyphenylene sulfide film is less than or equal to 0.08 mu m, the planarity is excellent, the thickness uniformity of a subsequent copper plating layer can be greatly improved, the uniformity is less than 5%, and the influence on the performance of the whole functional film is small. Therefore, it can be used to prepare an anode current collector.

The invention also discloses a preparation process of the polyphenylene sulfide film suitable for the ultrathin coating, which combines a coating process with a process for preparing the polyphenylene sulfide film in the prior art, but the time for combining the two processes is particularly critical and needs to be carried out after longitudinal stretching and before transverse stretching. The polymer prepared by combining the time has low surface roughness and excellent planarity, and is more favorable for improving the thickness uniformity of a subsequent coating.

Detailed Description

The present invention is further illustrated by the following specific examples, but the scope of the present invention is not limited to the following examples.

Example 1

Firstly, solid polyphenylene sulfide powder (NHU-PPS 3505, Zhejiang Xinhe special material Co., Ltd., the same below) is melted, extruded by a double-screw extruder, and then granulated into granular solid, and then the granular solid is put into vacuum drying, excess moisture is taken away by controlling introduced dry nitrogen, the dried polyphenylene sulfide granules are sent into the double-screw extruder, melted at 290 ℃, sent to a die head for extrusion, and then cooled and shaped by a chilling roller and an electrostatic adsorption device, so that the melt becomes a sheet with high flatness and low crystallinity.

Then sending the sheet into a longitudinal stretcher for stretching by 3.4 times, and introducing the longitudinally stretched film into a coating machine through a guide roller; 1.5 wt% of epoxy resin (EPIKOTE 1007-CT-55, Vast. Van. Seikon, solid content is 55%, the same is applied below), 1.5 wt% of polyphenylene sulfide resin (melt flow rate is 3500g/10min), 0.2 wt% of dimethylaminopropylamine, 5 wt% of ethanol, 0.05 wt% of nano copper powder (D90 ═ 80nm) and the balance of water are mixed and stirred uniformly to prepare a high polymer solution, a liquid supply pump of the coating machine conveys the high polymer solution to a slit of the coating machine, the solution extruded from the slit is sprayed to two sides of the film, and then a roller with reticulate is used for scraping the solution uniformly.

The coated film is introduced into a transverse stretcher, the film is introduced into an oven to be preheated along with the transmission of a chain clamp, and simultaneously, the solvent in the coating liquid is volatilized, so that a layer of high molecular polymer coating is left to be stretched 3.8 times together with the film substrate, and is subjected to heat setting and cooling. Then the film with the thickness of 4 mu m after biaxial tension is cut edge and measured thickness after being transmitted by a traction device, and the film is sent to a winding device to be wound and collected by the tension of 50N and the pressure of 0.05MPa to form a coiled material.

And carrying out vapor deposition on copper with the thickness of 1 mu m on two surfaces of the film collected into the coiled material in a vacuum evaporation mode, and finally preparing the copper into a negative current collector serving as energy storage equipment.

The specific flow of vacuum evaporation is as follows:

the vacuum chamber is pumped to the vacuum degree of 6 multiplied by 10^-3Pa, heating the copper to the evaporation temperature through an evaporation source to gasify the copper, performing ion bombardment under the condition of 600V of voltage, wherein the bombardment time is 30min, then cooling to 50 ℃, and closing the vacuum chamber.

The evaluation results of the negative electrode current collector of PPS film substrate prepared in this example are shown in table 1, and the negative electrode current collector has excellent film planarity and excellent thickness uniformity of the copper plating layer.

Example 2

In this example, 2.5 wt% of epoxy resin, 2.5 wt% of polyphenylene sulfide resin (melt flow rate of 3500g/10min), 0.2 wt% of dimethylaminopropylamine, 5 wt% of ethanol, 0.05 wt% of copper nanoparticles (D90 ═ 80nm), and the balance of water were mixed and stirred uniformly to prepare a polymer solution. Except for this, a negative electrode current collector of a PPS film substrate was fabricated by the same procedure as in example 1.

Example 3

In this example, 1.5 wt% of epoxy resin, 1.5 wt% of polyphenylene sulfide resin (melt flow rate: 4000g/10min), 0.2 wt% of dimethylaminopropylamine, 5 wt% of ethanol, 0.05 wt% of copper nanoparticles (D90 ═ 80nm), and the balance of water were mixed and stirred uniformly to prepare a polymer solution. Except for this, a negative electrode current collector of a PPS film substrate was fabricated by the same procedure as in example 1.

Example 4

In this example, 1.5 wt% of an epoxy resin, 1.5 wt% of a polyphenylene sulfide resin (melt flow rate of 3500g/10min), 0.2 wt% of dimethylaminopropylamine, 5 wt% of ethanol, 0.05 wt% of a copper nanoparticle (D90 ═ 100nm), and the balance of water were mixed and stirred uniformly to prepare a polymer solution. Except for this, a negative electrode current collector of a PPS film substrate was fabricated by the same procedure as in example 1.

Example 5

In this example, 1.5 wt% of epoxy resin, 1.5 wt% of polyphenylene sulfide resin (melt flow rate of 3500g/10min), 0.2 wt% of polyether diamine, 8 wt% of ethanol, 0.05 wt% of copper nanoparticles (D90 ═ 80nm), and the balance of water were mixed and stirred uniformly to prepare a polymer solution. Except for this, a negative electrode current collector of a PPS film substrate was fabricated by the same procedure as in example 1.

Example 6

In this example, 1.5 wt% of epoxy resin, 1.5 wt% of polyphenylene sulfide resin (melt flow rate of 3500g/10min), 0.4 wt% of dimethylaminopropylamine, 5 wt% of ethanol, 0.05 wt% of copper nanoparticles (D90 ═ 80nm), and the balance of water were mixed and stirred uniformly to prepare a polymer solution. Except for this, a negative electrode current collector of a PPS film substrate was fabricated by the same procedure as in example 1.

Example 7

In this example, 1.5 wt% of epoxy resin, 1.5 wt% of polyphenylene sulfide resin (melt flow rate of 3500g/10min), 0.2 wt% of polyether diamine, 5 wt% of ethanol, 0.08 wt% of copper nanoparticles (D90 ═ 80nm), and the balance of water were mixed and stirred uniformly to prepare a polymer solution. Except for this, a negative electrode current collector of a PPS film substrate was fabricated by the same procedure as in example 1.

Example 8

In this example, 1.5 wt% of epoxy resin, 1.5 wt% of polyphenylene sulfide resin (melt flow rate of 3500g/10min), 0.2 wt% of polyether diamine, 5 wt% of ethanol, 0.05 wt% of nano calcium carbonate (D90 ═ 80nm), and the balance of water were mixed and stirred uniformly to prepare a polymer solution. Except for this, a negative electrode current collector of a PPS film substrate was fabricated by the same procedure as in example 1.

Example 9

In this example, 1.5 wt% of epoxy resin, 1.5 wt% of polyphenylene sulfide resin (melt flow rate of 3500g/10min), 0.2 wt% of triethylene tetramine, 5 wt% of ethanol, 0.05 wt% of nano alumina (D90 ═ 80nm), and the balance of water were mixed and stirred uniformly to prepare a polymer solution. Except for this, a negative electrode current collector of a PPS film substrate was fabricated by the same procedure as in example 1.

Example 10

In this example, 1.5 wt% of epoxy resin, 1.5 wt% of polyphenylene sulfide resin (melt flow rate of 3500g/10min), 0.2 wt% of triethylene tetramine, 5 wt% of butyl acetate, 0.05 wt% of copper nanoparticles (D90 ═ 80nm) and the balance of water were mixed and stirred uniformly to prepare a polymer solution. Except for this, a negative electrode current collector of a PPS film substrate was fabricated by the same procedure as in example 1.

Example 11

In this example, 1.5 wt% of epoxy resin, 1.5 wt% of polyphenylene sulfide resin (melt flow rate of 3500g/10min), 0.2 wt% of triethylene tetramine, 5 wt% of isopropanol, 0.05 wt% of copper nanoparticles (D90 ═ 80nm), and the balance of water were mixed and stirred uniformly to prepare a polymer solution. Except for this, a negative electrode current collector of a PPS film substrate was fabricated by the same procedure as in example 1.

Comparative example 1

In this comparative example, 3.0 wt% of polyphenylene sulfide resin (melt flow rate: 3500g/10min), 0.2 wt% of dimethylaminopropylamine, 5 wt% of ethanol, 0.05 wt% of copper nanoparticles (D90 ═ 80nm) and the balance of water were mixed and stirred uniformly to prepare a polymer solution. Except for this, a negative electrode current collector of a PPS film substrate was fabricated by the same procedure as in example 1.

The evaluation results of the negative electrode current collector of the PPS film substrate prepared in this comparative example are shown in table 1, and the film planarity is deteriorated and the thickness uniformity of the copper plating layer is deteriorated.

Comparative example 2

In this comparative example, 1.5 wt% of polyurethane resin (impranil LPRSC1554, Bayer, solid content of 55%), 1.5 wt% of polyphenylene sulfide resin (melt flow rate of 3500g/10min), 0.2 wt% of dimethylaminopropylamine, 5 wt% of ethanol, 0.05 wt% of copper nanopowder (D90 ═ 80nm), and the balance of water were mixed and stirred uniformly to prepare a polymer solution. Except for this, a negative electrode current collector of a PPS film substrate was fabricated by the same procedure as in example 1.

Comparative example 3

In this comparative example, 1.5 wt% of epoxy resin, 1.5 wt% of polyphenylene sulfide resin (melt flow rate: 2500g/10min), 0.2 wt% of dimethylaminopropylamine, 5 wt% of ethanol, 0.05 wt% of copper nanoparticles (D90 ═ 80nm), and the balance of water were mixed and stirred uniformly to prepare a polymer solution. Except for this, a negative electrode current collector of a PPS film substrate was fabricated by the same procedure as in example 1.

Comparative example 4

In this comparative example, 1.5 wt% of epoxy resin, 1.5 wt% of polyphenylene sulfide resin (melt flow rate of 3500g/10min), 0.2 wt% of dimethylaminopropylamine, 5 wt% of ethanol, 0.05 wt% of copper nanoparticles (D90 ═ 150nm), and the balance of water were mixed and stirred uniformly to prepare a polymer solution. Except for this, a negative electrode current collector of a PPS film substrate was fabricated by the same procedure as in example 1.

Comparative example 5

Firstly, solid polyphenylene sulfide powder is melted, extruded by a double-screw extruder, granulated into granular solid after being extruded, and then placed into a vacuum chamber for drying, and excess moisture is taken away by controlling introduced dry nitrogen to be used as a final film manufacturing raw material. And (3) feeding the dried polyphenylene sulfide particles into a double-screw extruder, melting at 290 ℃, then feeding the molten polyphenylene sulfide particles into a die head for extrusion, and cooling and shaping by using a chill roll and an electrostatic adsorption device to obtain a cast sheet, so that the melt becomes a sheet with high flatness and low crystallinity.

After the sheet was cast, the sheet was introduced into a coater, and 1.5 wt% of epoxy resin, 1.5 wt% of polyphenylene sulfide resin (melt flow rate of 3500g/10min), 0.2 wt% of dimethylaminopropylamine, 5 wt% of ethanol, 0.05 wt% of copper nanoparticles (D90 ═ 80nm) and the balance of water were mixed and stirred uniformly to prepare a polymer solution, the polymer solution was sent to a slit of the coater by a feed pump of the coater, the solution extruded from the slit was sprayed to both sides of the film, and the solution was scraped uniformly by a roll having a mesh pattern.

And then sending the sheet into a longitudinal stretcher for preheating to volatilize the solvent in the high molecular polymer solution, stretching by 3.4 times, then introducing the film into an oven for preheating along with the transmission of a chain clamp, stretching by 3.8 times, and performing heat setting and cooling. Then the film with the thickness of 4 mu m after biaxial tension is cut edge and measured thickness after being transmitted by a traction device, and the film is sent to a winding device to be wound and collected by the tension of 50N and the pressure of 0.05MPa to form a coiled material.

Except for this, a negative electrode current collector of a PPS film substrate was fabricated by the same procedure as in example 1.

In this comparative example, the same formulation of the polymer solution as in example 1 was used to prepare a negative electrode current collector of a PPS film substrate just before the longitudinal stretching process, and the evaluation results are shown in table 1, in which the film planarity was deteriorated and the thickness uniformity of the copper plating layer was deteriorated.

Comparative example 6

Firstly, solid polyphenylene sulfide powder is melted, a double-screw extruder is used for extrusion, the extruded polyphenylene sulfide powder is cut into granular solid, then the granular solid is placed in a vacuum drying mode, and excess moisture is taken away by controlling introduced dry nitrogen to serve as a final film manufacturing raw material. And (3) feeding the dried polyphenylene sulfide particles into a double-screw extruder, melting at 290 ℃, then feeding the molten polyphenylene sulfide particles into a die head for extrusion, and cooling and shaping by using a chilling roller and an electrostatic adsorption device to enable the melt to become a sheet with high flatness and low crystallinity.

And then the sheet is sent into a longitudinal stretcher to be stretched by 3.4 times, and the film stretched longitudinally is introduced into a transverse stretcher oven along with the transmission of a chain clamp to be preheated, stretched by 3.8 times, shaped and cooled. The film after the transverse drawing was introduced into a coater, a high molecular polymer solution was prepared using the same formulation as in example 1, the high molecular polymer solution was fed to the slit of the coater by a coater feed pump, the solution extruded from the slit was sprayed to both sides of the film, and the solution was scraped evenly by a roll having a texture. And then the film is continuously put into a section of oven to be heated, the solvent in the high molecular solution is volatilized, and the mixed resin is solidified. And finally, conveying the film by a traction device, cutting the edge of the 4-micron film, measuring the thickness of the film, and feeding the film into a winding device to wind and collect the film into a coiled material under the tension of 50N and the pressure of 0.05 MPa.

And plating copper with the thickness of 1um on two surfaces of the film collected into the coiled material in a vapor deposition copper plating mode, and finally preparing the negative current collector of the energy storage equipment.

In this comparative example, the same formulation of the polymer solution as in example 1 was used to prepare a negative electrode current collector of a PPS film substrate by simply delaying the coating process until the transverse stretching process, and the evaluation results are shown in table 1, in which the film planarity was deteriorated and the thickness uniformity of the copper plating layer was deteriorated.

And (3) performance testing:

1. roughness of

The test was carried out according to the method GB/T14234-1993, using a mahr roughness tester. The stylus method is used for 10 times of testing, and the average value is taken.

2. Melt flow rate of PPS resin

The PPS resin in the coating was tested 3 times using a melt flow rate meter according to the method of GB/T3682, and the average value was taken.

3. Thickness and uniformity of copper plating layer

According to the method of GB/T15717, the vacuum metal plating thickness measuring instrument is used for testing. Sample size: the length is 300mm, the width is 100mm plus or minus 0.1mm, and the number is not less than 10.

And testing the resistance value of the square resistor of the metal coating for 10 times, and taking the maximum value, the minimum value and the calculated average value.

TABLE 1

Claims

1. A polyphenylene sulfide film suitable for ultrathin plating, comprising: the upper surface and the lower surface of the polyphenylene sulfide film layer are respectively provided with a polymer coating;

the polyphenylene sulfide film layer does not contain an opening agent in raw material composition;

1-3% of polyphenylene sulfide resin;

1-3% of epoxy resin;

0.02-1% of a nano opening agent;

0.1-0.4% of curing agent;

3-8% of an organic solvent;

the balance of water;

the melt flow rate of the polyphenylene sulfide resin is 3500-4000 g/10 min;

the particle size D90= 80-100 nm of the nano opening agent;

the preparation method of the polyphenylene sulfide film suitable for the ultrathin coating comprises the following steps:

(1) taking polyphenylene sulfide resin without a opening agent as a raw material, and obtaining a polyphenylene sulfide sheet after melt extrusion, cooling and sizing;

2. The polyphenylene sulfide film suitable for ultrathin plating according to claim 1, wherein:

the nano opening agent is selected from one or more of nano copper powder, nano calcium carbonate and nano aluminum oxide;

the organic solvent is selected from one or more of ethanol, butyl acetate and isopropanol.

3. The polyphenylene sulfide film suitable for ultrathin plating according to any one of claims 1 to 2, wherein:

1.5-2.5% of polyphenylene sulfide resin;

1.5-2.5% of epoxy resin;

0.05-0.08% of nano opening agent;

0.2-0.4% of curing agent;

5-8% of an organic solvent;

the balance of water.

4. The polyphenylene sulfide film suitable for ultrathin plating according to claim 1, wherein:

in the step (2), the longitudinal stretching magnification is 3-4;

in the step (3), the transverse stretching magnification is 3-4.

5. A negative electrode current collector, comprising the polyphenylene sulfide thin film suitable for ultra-thin plating according to any one of claims 1 to 4; the ultrathin plating layer is characterized by also comprising copper layers plated on the upper surface and the lower surface of the polyphenylene sulfide film suitable for the ultrathin plating layer respectively.

6. The negative electrode current collector of claim 5, wherein:

the thickness of the copper layer is 0.5-1.5 μm.