CN111098533A - Preparation method of hard elastic polypropylene film, hard elastic polypropylene film and application - Google Patents
Preparation method of hard elastic polypropylene film, hard elastic polypropylene film and application Download PDFInfo
- Publication number
- CN111098533A CN111098533A CN201911419358.7A CN201911419358A CN111098533A CN 111098533 A CN111098533 A CN 111098533A CN 201911419358 A CN201911419358 A CN 201911419358A CN 111098533 A CN111098533 A CN 111098533A
- Authority
- CN
- China
- Prior art keywords
- temperature
- cooling
- annealing
- heating
- film
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Images
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C71/00—After-treatment of articles without altering their shape; Apparatus therefor
- B29C71/02—Thermal after-treatment
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
- B29C48/001—Combinations of extrusion moulding with other shaping operations
- B29C48/0018—Combinations of extrusion moulding with other shaping operations combined with shaping by orienting, stretching or shrinking, e.g. film blowing
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
- B29C48/03—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor characterised by the shape of the extruded material at extrusion
- B29C48/07—Flat, e.g. panels
- B29C48/08—Flat, e.g. panels flexible, e.g. films
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
- H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
- H01M50/403—Manufacturing processes of separators, membranes or diaphragms
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
- H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
- H01M50/409—Separators, membranes or diaphragms characterised by the material
- H01M50/411—Organic material
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C71/00—After-treatment of articles without altering their shape; Apparatus therefor
- B29C71/02—Thermal after-treatment
- B29C2071/022—Annealing
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29K—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
- B29K2023/00—Use of polyalkenes or derivatives thereof as moulding material
- B29K2023/10—Polymers of propylene
- B29K2023/12—PP, i.e. polypropylene
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29L—INDEXING SCHEME ASSOCIATED WITH SUBCLASS B29C, RELATING TO PARTICULAR ARTICLES
- B29L2007/00—Flat articles, e.g. films or sheets
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/10—Energy storage using batteries
Abstract
The application discloses a preparation method of a hard elastic polypropylene film, the hard elastic polypropylene film and application. The preparation method comprises the following steps of heating according to one or a combination of the following two heating modes and cooling according to one or a combination of the following two cooling modes during annealing treatment; heating at a speed of 1-5 ℃/min in a first heating mode; a second heating mode is that the temperature is kept after being heated to 70-100 ℃, and then the temperature is kept for a period of time at 5-20 ℃ per liter; cooling at a speed of 1-5 ℃/min in a first cooling mode; and a second cooling mode, namely, cooling the temperature to 5-20 ℃ for a period of time, cooling the temperature to 70-100 ℃ and keeping the temperature, and then cooling the temperature from 70-100 ℃ to room temperature. The method adopts slow or gradient temperature rise and slow or gradient temperature reduction, can better keep the initial crystallization of the casting film, keeps the consistent stability of the structure after annealing, ensures that the prepared hard elastic polypropylene film has good lamellar structure and orientation, and lays a foundation for preparing the polypropylene microporous film with uniform pore structure.
Description
Technical Field
The application relates to the technical field of battery diaphragm production, in particular to a preparation method of a hard elastic polypropylene film, the hard elastic polypropylene film and application.
Background
The lithium battery diaphragm is used as a key material in the battery, not only plays a role in isolating positive and negative electrodes, but also reserves a lithium ion transmission channel. Polyolefin materials, such as polyethylene, polypropylene, etc., are used as classical polymer materials for preparing lithium battery separators due to their excellent chemical resistance, processability, etc. At present, polyolefin-based separators are classified into wet-process membranes and dry-process membranes according to the process. Wet films are represented by polyethylene, and the mechanism adopted is thermally induced phase separation, the process is complex and the use of solvents in the production process is destructive to the environment. Dry-process films are represented by polypropylene and are classified into unidirectional stretching and bidirectional stretching processes, wherein the unidirectional stretching polypropylene film is widely concerned because the process is relatively simple, the pore formation is uniform and no pollution is caused to the environment.
The dry-process single-drawing polypropylene diaphragm is prepared by firstly melting and extruding a polypropylene melt, preparing a hard elastic polypropylene precursor film with a regular lamellar structure by combining a tape casting process, then carrying out heat treatment or annealing treatment on the precursor film, and then carrying out cold and hot stretching to separate the lamellar so as to form pores. The subsequent stretching process is based on the fact that the hard elastic polypropylene film has a good platelet structure and a good platelet orientation, and therefore, it is particularly important to prepare an excellent hard elastic polypropylene film.
Annealing is a key factor for adjusting the performance of the hard elastic film, and the cast film is usually baked at a suitable annealing temperature, for example, 140-. Theoretically, the hard elastic polypropylene film with good platelet structure and platelet orientation can be obtained through annealing treatment, so that the polyolefin microporous film with uniform pore size and distribution can be obtained through stretching.
However, in practical production, it is found that some of the platelets are still imperfect during annealing treatment, and melt recrystallization of the imperfect crystals is always accompanied, and even if the temperature of the annealing treatment is increased and the annealing time is prolonged, the problem is difficult to solve; in addition, during annealing treatment, the initial crystallization of the casting film can be seriously damaged, which is not beneficial to controlling the structural consistency and stability after the baking of the annealing treatment; these all affect the properties of the polyolefin microporous film obtained by final stretching.
Disclosure of Invention
The object of the present application is to provide an improved method for the preparation of a stiff elastic polypropylene film, the stiff elastic polypropylene film prepared and its use.
In order to achieve the purpose, the following technical scheme is adopted in the application:
one aspect of the application discloses a preparation method of a hard elastic polypropylene film, which comprises the steps of placing a precursor film in a heating device during annealing treatment, heating to an annealing temperature according to the following heating mode, carrying out annealing treatment, cooling to room temperature according to the following cooling mode after annealing treatment, and cooling at room temperature to finish the whole annealing step;
the heating method of the present application is one or a combination of two methods,
heating to the annealing temperature at the speed of 1-5 ℃/min in a first heating mode;
in the second heating mode, the temperature is kept for a period of time after the temperature is raised to 70-100 ℃, and then the temperature is kept for a period of time after the temperature is raised to 5-20 ℃ until the temperature is raised to the annealing temperature;
the cooling mode of the present application is one or a combination of the following two modes,
cooling from the annealing temperature to room temperature at a speed of 1-5 ℃/min;
and a second cooling mode, namely cooling from the annealing temperature, keeping the temperature for a period of time every time the temperature is reduced to 5-20 ℃ until the temperature is reduced to 70-100 ℃, keeping the temperature for a period of time, and then directly cooling from 70-100 ℃ to room temperature.
In the application, the hard elastic polypropylene film is a film formed by annealing a casting film, and is further stretched and shaped on the basis of the hard elastic polypropylene film, so that the polypropylene microporous film for preparing the battery diaphragm is obtained.
In the preparation method, during annealing treatment, the polypropylene casting film (i.e. the precursor film) is subjected to heat treatment by creatively adopting slow temperature rise or gradient temperature rise to a proper annealing temperature, and then is cooled by adopting a slow temperature reduction or gradient temperature reduction method. The heat treatment method can better keep the initial crystallization condition of the polypropylene film, is favorable for controlling the consistency of the crystal structure of the casting film, thereby obtaining the hard elastic polypropylene film with good platelet structure and platelet orientation, and laying a foundation for preparing the polypropylene microporous film with uniform pore structure and uniform pore size and distribution.
The key point of the application is that the temperature is slowly increased or increased in a gradient manner, and is slowly decreased or decreased in a gradient manner, and the temperature is maintained for a period of time in the second temperature increasing manner and the second temperature decreasing manner, which can be determined according to production conditions or product requirements; for example, in an implementation manner of the present application, the heat preservation period refers to heat preservation for 5min to 2h, and the principle is that the closer the temperature is raised, the longer the heat preservation period is; the heat preservation time of each stage is basically the same when the temperature is reduced, for example, the heat preservation time is 10-20 min. The reason why the temperature is closer to the annealing temperature and the heat preservation time is longer in the temperature rise is that the temperature rise process is more critical to be 120-140 ℃ in the annealing treatment, and the heat preservation time in the range is generally longer, for example, in one implementation manner of the application, the temperature is preserved for 30min at 120 ℃, 30min at 130 ℃ and 1-2h at 140 ℃.
It should be noted that the key point of the present application lies in the improvement of the heating and cooling manner of the annealing treatment, and as for other steps, such as the temperature and time of the annealing treatment, the film casting before the annealing treatment, and the subsequent compounding, stretching, sizing, etc., reference can be made to the existing polypropylene microporous film production process, which is not limited herein.
Preferably, the annealing temperature is 140-.
The other side of the application discloses a hard elastic polypropylene film prepared by the preparation method.
It can be understood that the hard elastic polypropylene film of this application, owing to adopt the special intensification mode and the cooling mode of this application, can keep the initial crystallization situation of polypropylene film better, be favorable to controlling the uniformity of curtain coating membrane crystal structure, consequently, the hard elastic polypropylene film of this application has better platelet structure and platelet orientation to can be used for preparing the more even polypropylene microporous membrane of pore structure.
In yet another aspect, the present application discloses the use of the stiff elastic polypropylene films of the present application in the preparation of polypropylene microporous membranes or battery separator films.
It can be understood that the hard elastic polypropylene film can prepare a polypropylene microporous film with a more uniform pore structure, and the polypropylene microporous film can be directly used as a battery diaphragm or coated on the basis to prepare a coating diaphragm. The polypropylene microporous membrane or the battery diaphragm prepared by the hard elastic polypropylene membrane has a more uniform pore structure, and has important significance for improving the comprehensive performance of the battery diaphragm.
One more aspect of the present application discloses a polypropylene microporous membrane prepared with the hard elastic polypropylene film of the present application.
Preferably, the polypropylene microporous membrane has the thickness of 10-30 μm, the porosity of 30-60% and the pore diameter of 5-50 nm.
The application also discloses an annealing treatment method of the cast film, which comprises the steps of heating to an annealing temperature according to the following heating mode, carrying out annealing treatment, cooling to room temperature according to the following cooling mode after annealing treatment, and cooling at room temperature to finish the whole annealing step;
in the annealing treatment method of the present application, the temperature raising method is one of the following two methods or a combination of both,
heating to the annealing temperature at the speed of 1-5 ℃/min in a first heating mode;
in the second heating mode, the temperature is kept for a period of time after the temperature is raised to 70-100 ℃, and then the temperature is kept for a period of time after the temperature is raised to 5-20 ℃ until the temperature is raised to the annealing temperature;
in the annealing treatment method of the present application, the cooling method is one or a combination of two methods,
cooling from the annealing temperature to room temperature at a speed of 1-5 ℃/min;
and a second cooling mode, namely cooling from the annealing temperature, keeping the temperature for a period of time every time the temperature is reduced to 5-20 ℃ until the temperature is reduced to 70-100 ℃, keeping the temperature for a period of time, and then directly cooling from 70-100 ℃ to room temperature.
The annealing treatment method is mainly used for a polypropylene cast film or a co-extrusion cast film containing the polypropylene cast film, and can maintain the initial crystallization of the polypropylene cast film or the co-extrusion cast film containing the polypropylene cast film, maintain the structural consistency and stability and finally prepare the microporous membrane with uniform pore structure.
Due to the adoption of the technical scheme, the beneficial effects of the application are as follows:
according to the preparation method of the hard elastic polypropylene film, annealing treatment is carried out by slowly raising the temperature or gradient raising the temperature to the annealing temperature, and then cooling is carried out by slowly lowering the temperature or gradient lowering the temperature, so that initial crystallization of the cast film can be better kept, and structural consistency and stability after annealing are kept, and therefore the prepared hard elastic polypropylene film has a good lamellar crystal structure and lamellar crystal orientation, and a foundation is laid for preparing a polypropylene microporous film with a uniform pore structure.
Drawings
FIG. 1 is a schematic diagram of the temperature profile of the annealing treatment in example 1 of the present application;
FIG. 2 is a schematic diagram of the temperature profile of the annealing treatment in example 2 of the present application;
FIG. 3 is a schematic temperature program of annealing treatment in example 3 of the present application;
FIG. 4 is a schematic temperature program of annealing treatment in example 4 of the present application;
FIG. 5 is a scanning electron micrograph of a polypropylene microporous membrane according to example 2 of the present application.
Detailed Description
The inventor of the application finds that in the practical baking of the battery diaphragm, in the actual baking of the annealing treatment, after the temperature of the oven reaches the set temperature, the cast film is directly placed in the oven for baking, although the annealing temperature does not reach the melting point of a sample, for polypropylene, due to the fact that partial lamella is incomplete during the annealing treatment, the melt recrystallization of the incomplete crystal is always accompanied, especially the cast film is placed at the annealing temperature instantly, the initial crystallization of the cast film is seriously damaged at the moment, the structural consistency and stability of the cast film after baking are not favorably controlled, and the performance of the porous film obtained by final stretching is influenced.
Based on the knowledge, the application creatively provides an improved preparation method of the hard elastic polypropylene film, namely, the temperature is raised to the annealing temperature at the speed of 1-5 ℃/min, or the temperature is kept for a period of time after the temperature is raised to 70-100 ℃, and then the temperature is kept for a period of time after the temperature is raised to 5-20 ℃ every time until the temperature is raised to the annealing temperature; after the annealing is finished, the temperature is reduced from the annealing temperature to the room temperature at the speed of 1-5 ℃/min, or the temperature is reduced from the annealing temperature, the temperature is preserved for a period of time every time the temperature is reduced to 5-20 ℃, the temperature is reduced to 70-100 ℃ and preserved for a period of time, and then the temperature is directly reduced from 70-100 ℃ to the room temperature. According to the preparation method, the cast film is gradually heated to the annealing temperature, so that initial crystallization damage caused by the fact that the cast film is instantly placed at the annealing temperature is avoided; and moreover, the cooling is carried out in a gradual cooling mode, so that the consistency and the stability of the structure are guaranteed to the greatest extent.
The present application is described in further detail below with reference to specific embodiments and the attached drawings. The following examples are intended to be illustrative of the present application only and should not be construed as limiting the present application.
Example 1
In this example, the melt index was 5.0(g/10min, 230 ℃ C.), and the weight-average molecular weight was 5X 105Extruding the melt by a screw extruder to form a film by casting to obtain a casting film with the thickness of 25 mu m from a polypropylene raw material with the molecular weight distribution of 2-8; then annealing the casting film to obtain the hard elastic polypropylene film of the embodiment; and compounding and stretching the hard elastic polypropylene film to obtain the polypropylene microporous film. The key point of the embodiment is to improve the annealing treatment, and the existing preparation process of the polypropylene microporous membrane can be referred for extrusion casting, compounding, stretching and the like.
The preparation method of the polypropylene microporous membrane in the embodiment is detailed as follows:
(1) extrusion casting: melting and extruding a polypropylene raw material by an extruder, wherein the rotating speed of a screw of a casting rolling extruder is 300rpm, the extrusion temperature is 300 ℃, the temperature of a die head is 250 ℃, the casting drafting speed is 100m/min, and the temperature of a casting roller is 80 ℃;
(2) annealing: placing the casting film in a room temperature oven, raising the temperature to 145 ℃ at the heating rate of 3 ℃/min for annealing for 12h, then lowering the temperature of the oven to room temperature at the cooling rate of 3 ℃/min, and finally cooling the polypropylene film at room temperature for 12h to finish heat treatment, so as to obtain the hard elastic polypropylene film of the embodiment, wherein the schematic diagram of the annealing temperature procedure is shown in fig. 1;
(3) compounding: physically compounding the annealed casting film to prepare a composite film;
(4) stretching: the composite membrane is firstly cold-drawn at low temperature to form initial micropores, then the initial micropores are stretched at high temperature to expand the pores, a large number of holes with uniform pore size distribution are formed, and then the polypropylene microporous membrane is prepared by cooling after shaping at higher temperature; wherein, the cold drawing temperature of the corresponding diaphragm is 80 ℃, and the cold drawing multiplying power is 1.1; the hot stretching multiplying power is 1.8, and the hot stretching temperature is 145 ℃; the setting temperature is 165 ℃ and the setting multiplying power is 0.8. The inlet speed is 3-7 m/min.
Example 2
In this example, the specific manner of "(2) annealing" was adjusted based on example 1, and the rest was the same as example 1, specifically as follows:
annealing: and (3) placing the cast film in a room temperature oven, and selecting a gradient temperature rise program to raise the temperature to 145 ℃ of annealing temperature, wherein the gradient temperature rise program is specifically to raise the room temperature to 100 ℃ and keep the temperature for 5min, then raise the temperature to 120 ℃ and keep the temperature for 30min, then raise the temperature to 140 ℃ and keep the temperature for 2h, finally raise the temperature to 145 ℃ for annealing, the annealing time is 12h, then lower the oven temperature to room temperature by a gradient temperature drop program, the gradient temperature drop program is to lower the temperature to 140 ℃ and keep the temperature for 20min, then lower the temperature to 135 ℃ and keep the temperature for 20min, lower the temperature to 125 ℃ and keep the temperature for 10min, then lower the temperature to room temperature, and then cool the room temperature for 12h to finish heat treatment, so that the hard elastic polypropylene film of the embodiment is obtained, wherein the schematic diagram of.
The rest is the same as in example 1.
Example 3
In this example, the specific manner of "(2) annealing" was adjusted based on example 1, and the rest was the same as example 1, specifically as follows:
annealing: and (3) placing the cast film in a room temperature oven, selecting a gradient temperature rise program to heat to an annealing temperature of 150 ℃, wherein the gradient temperature rise program is specifically to heat the cast film to 100 ℃ for 5min, then heat the cast film to 120 ℃ for 30min, then heat the cast film to 130 ℃ for 30min, then heat the cast film to 140 ℃ for 2h, finally heat the cast film to 145 ℃ for annealing for 12h, then reduce the temperature of the oven to room temperature at a cooling rate of 3 ℃/min, and finally cool the polypropylene film at room temperature for 12h to complete heat treatment, thus obtaining the hard elastic polypropylene film of the embodiment, wherein the schematic diagram of the temperature program of the annealing treatment is shown in fig. 3.
The rest is the same as in example 1.
Comparative experiment 1
In this example, on the basis of example 1, the conventional annealing treatment mode is directly adopted to replace the annealing (2) in example 1, namely, the oven temperature is directly set to 145 ℃, after the oven temperature is stabilized, the cast film is rapidly placed in the oven to be annealed for 12h, then the polypropylene film is rapidly taken out of the oven, and is cooled for 12h at room temperature to complete the heat treatment, and the hard elastic polypropylene film in the example is obtained. The temperature program of the annealing treatment is schematically shown in FIG. 4. The rest is the same as in example 1.
The resilience test was performed on the hard elastic polypropylene films of the above examples and comparative tests.
And (3) resilience testing: cutting the cast film into standard film samples with a gauge length of L0Stretching the film sample to L at a speed of 50mm/min using a universal tensile tester1＝2L0Timing is 60 s. Returning the stretched film sample to the initial position of the gauge length, timing for 180s, taking down the film, straightening, measuring the length L after the return2. Poly two cast film elastic recovery calculation formula: ER ═ L1-L2)/(L1-L0)
The test results are shown in table 1.
TABLE 1 sequencing results for hard elastic Polypropylene film Properties
The results in table 1 show that the stiff elastic polypropylene film prepared in example 2 has the best resilience, and the effects of the gradient temperature rise and gradient temperature fall pattern of example 2 are best. In terms of orientation, the hard elastic polypropylene film of example 2 was oriented 175, while the hard elastic polypropylene film of comparative test 1 was oriented 165, it is clear that the hard elastic polypropylene film of example 2 was oriented better than comparative test 1.
The polypropylene microporous membrane prepared in example 2 was observed by a scanning electron microscope, and the result is shown in fig. 5. The results in fig. 5 show that the pore structure of the microporous polypropylene membrane prepared in example 2 is uniform, consistent with the expected effect. The polypropylene microporous membranes prepared in the examples 1 and 3 and the comparative test 1 are observed by a scanning electron microscope, and the results show that the polypropylene microporous membrane prepared in the comparative test 1 has relatively poor pore structure uniformity, and relatively uneven pore size and micropore distribution; the pore uniformity of examples 1 and 3 is significantly better than that of comparative experiment 1.
Example 4
In this example, based on example 2, gradient temperature rise and gradient temperature fall are designed, and the rest of the non-mentioned parts are the same as example 2, and are detailed as follows:
test 1: gradient heating, raising the room temperature to 70 ℃, preserving heat for 5min, raising the room temperature to 90 ℃, preserving heat for 5min, raising the room temperature to 100 ℃, preserving heat for 5min, raising the room temperature to 105 ℃, preserving heat for 5min, raising the room temperature to 110 ℃, preserving heat for 5min, raising the room temperature to 115 ℃, preserving heat for 5min, raising the room temperature to 120 ℃, preserving heat for 15min, raising the room temperature to 125 ℃, preserving heat for 15min, raising the room temperature to 130 ℃, preserving heat for 30min, raising the room temperature to 140 ℃, preserving heat for 2h, finally raising the room temperature to 145 ℃ for annealing, wherein the annealing time is 12 h; gradient cooling, cooling to 140 deg.C, maintaining for 20min, cooling to 135 deg.C, maintaining for 20min, cooling to 125 deg.C, maintaining for 20min, cooling to 100 deg.C, maintaining for 10min, and cooling to room temperature.
Test 2: gradient heating, heating to 100 deg.C at room temperature for 5min, heating to 110 deg.C for 5min, heating to 120 deg.C for 30min, heating to 130 deg.C for 30min, heating to 140 deg.C for 2h, and heating to 145 deg.C for annealing for 12 h; gradient cooling, cooling to 140 deg.C, maintaining for 20min, cooling to 135 deg.C, maintaining for 20min, cooling to 125 deg.C, maintaining for 20min, cooling to 100 deg.C, maintaining for 10min, and cooling to room temperature.
Test 3: gradient heating, heating to 100 deg.C at room temperature for 5min, heating to 120 deg.C for 30min, heating to 140 deg.C for 2h, and heating to 145 deg.C for annealing for 12 h; gradient cooling, cooling to 140 deg.C, keeping the temperature for 20min, cooling to 135 deg.C, keeping the temperature for 20min, cooling to 125 deg.C, keeping the temperature for 20min, cooling to 100 deg.C, keeping the temperature for 10min, cooling to 80 deg.C, keeping the temperature for 10min, cooling to 70 deg.C, keeping the temperature for 10min, and cooling to room temperature.
The resilience test was performed on the stiff elastic polypropylene films prepared in the above three tests, and the results are shown in table 2.
TABLE 2 sequencing results of the properties of hard elastic polypropylene films prepared by different gradient temperature-rising procedures
| Test number | Rebound resilience (%) |
| Test 1 | 97.5 |
| Test 2 | 97.3 |
| Test 3 | 97.1 |
The results in table 2 show that the hard elastic polypropylene film obtained by using more temperature gradients in the gradient temperature rise process has better rebound resilience effect, the processing in the temperature range of 120 ℃ to 140 ℃ is more critical, the heat preservation time in the temperature range can be longer, for example, the heat preservation time is 30min to 2h, and the heat preservation time in the rest temperature gradients can be relatively shorter, for example, the heat preservation time is 5min to 30 min.
In general, the temperature can be directly raised to 70-100 ℃ in the temperature raising stage, the temperature is kept for 5-30 min, and then the temperature is kept for 5-30 min every time the temperature is raised to 5-20 ℃; wherein, the temperature is increased to 120-130 ℃ for 30min-1h, the temperature is increased to 140 ℃ for 1-2h, and then the temperature is increased to the annealing temperature, and in the process, the more the designed temperature gradient is, the better the annealing effect is. And in the cooling stage, cooling from the annealing temperature, keeping the temperature for 10-20min at 5-20 ℃ every time until the temperature is reduced to 70-100 ℃ and keeping the temperature for 10-20min, and then directly cooling from 70-100 ℃ to room temperature.
Example 5
In this example, the rate of temperature increase and decrease was tested based on example 1, and the rest of the test was the same as example 1, specifically as follows:
test 1: heating to the annealing temperature of 150 ℃ at the heating rate of 1 ℃/min, annealing for 12h, and then cooling the oven to the room temperature at the cooling rate of 1 ℃/min.
Test 2: heating to the annealing temperature of 150 ℃ at the heating rate of 2 ℃/min, annealing for 12h, and then cooling the oven to the room temperature at the cooling rate of 2 ℃/min.
Test 3: heating to the annealing temperature of 150 ℃ at the heating rate of 4 ℃/min, annealing for 12h, and then cooling the oven to the room temperature at the cooling rate of 4 ℃/min.
Test 4: heating to the annealing temperature of 150 ℃ at the heating rate of 5 ℃/min, annealing for 12h, and then cooling the oven to the room temperature at the cooling rate of 5 ℃/min.
Test 5: heating to the annealing temperature of 150 ℃ at the heating rate of 6 ℃/min, annealing for 12h, and then cooling the oven to the room temperature at the cooling rate of 6 ℃/min.
Test 6: heating to the annealing temperature of 150 ℃ at the heating rate of 3 ℃/min, annealing for 12h, and then cooling the oven to the room temperature at the cooling rate of 6 ℃/min.
Test 7: heating to the annealing temperature of 150 ℃ at the heating rate of 6 ℃/min, annealing for 12h, and then cooling the oven to the room temperature at the cooling rate of 3 ℃/min.
The resilience test was performed on the hard elastic polypropylene films prepared in the above seven tests, and the results are shown in table 3.
TABLE 3 sequencing results of the properties of hard elastic polypropylene films prepared at different heating rates
| Test number | Rebound resilience (%) |
| Test 1 | 96.9 |
| Test 2 | 96.6 |
| Test 3 | 96.5 |
| Test 4 | 96.2 |
| Test 5 | 96.2 |
| Test 6 | 96.4 |
| Test 7 | 96.2 |
The results in Table 3 show that the slower the temperature rise, the better the rebound resilience effect of the hard elastic polypropylene film prepared, and the better the effect at a temperature rise rate of 1-5 ℃/min, and similarly, the better the effect at a temperature drop rate of 1-5 ℃/min. Comparative analysis of example 1 with tests 6 and 7 of this example shows that the impact on the rebound resilience of the hard elastic polypropylene film produced is large in the rate of temperature rise and small in the rate of temperature fall, but a preferred rate of temperature fall of 1 to 5 ℃/min is still better.
The foregoing is a more detailed description of the present application in connection with specific embodiments thereof, and it is not intended that the present application be limited to the specific embodiments thereof. It will be apparent to those skilled in the art from this disclosure that many more simple derivations or substitutions can be made without departing from the spirit of the disclosure.
Claims (7)
1. A preparation method of a hard elastic polypropylene film is characterized by comprising the following steps: placing the precursor film in a heating device during annealing treatment, heating to an annealing temperature according to the following heating mode, annealing, cooling to room temperature according to the following cooling mode after annealing treatment, and cooling at room temperature to finish the whole annealing step to obtain the hard elastic polypropylene film;
the heating mode is one or the combination of the following two modes,
heating to the annealing temperature at the speed of 1-5 ℃/min in a first heating mode;
in the second heating mode, the temperature is kept for a period of time after the temperature is raised to 70-100 ℃, and then the temperature is kept for a period of time after the temperature is raised to 5-20 ℃ until the temperature is raised to the annealing temperature;
the cooling mode is one or the combination of the following two modes,
cooling from the annealing temperature to room temperature at a speed of 1-5 ℃/min;
and a second cooling mode, namely cooling from the annealing temperature, keeping the temperature for a period of time every time the temperature is reduced to 5-20 ℃ until the temperature is reduced to 70-100 ℃, keeping the temperature for a period of time, and then directly cooling from 70-100 ℃ to room temperature.
2. The method of claim 1, wherein: the annealing temperature is 140-160 ℃.
3. The hard elastic polypropylene film produced by the production method according to claim 1 or 2.
4. Use of the stiff elastic polypropylene film according to claim 3 for the preparation of polypropylene microporous films or battery separators.
5. A polypropylene microporous membrane characterized by: the polypropylene microporous membrane is prepared by the hard elastic polypropylene membrane of claim 3.
6. The polypropylene microporous membrane according to claim 5, wherein: the polypropylene microporous membrane has the thickness of 10-30 mu m, the porosity of 30-60 percent and the pore diameter of 5-50 nm.
7. An annealing treatment method of a casting film, characterized in that: heating to an annealing temperature according to the following heating mode, carrying out annealing treatment, cooling to room temperature according to the following cooling mode after annealing treatment, and cooling at room temperature to finish the whole annealing step;
the heating mode is one or the combination of the following two modes,
heating to the annealing temperature at the speed of 1-5 ℃/min in a first heating mode;
in the second heating mode, the temperature is kept for a period of time after the temperature is raised to 70-100 ℃, and then the temperature is kept for a period of time after the temperature is raised to 5-20 ℃ until the temperature is raised to the annealing temperature;
the cooling mode is one or the combination of the following two modes,
cooling from the annealing temperature to room temperature at a speed of 1-5 ℃/min;
and a second cooling mode, namely cooling from the annealing temperature, keeping the temperature for a period of time every time the temperature is reduced to 5-20 ℃ until the temperature is reduced to 70-100 ℃, keeping the temperature for a period of time, and then directly cooling from 70-100 ℃ to room temperature.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201911419358.7A CN111098533B (en) | 2019-12-31 | 2019-12-31 | Preparation method of hard elastic polypropylene film, hard elastic polypropylene film and application |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201911419358.7A CN111098533B (en) | 2019-12-31 | 2019-12-31 | Preparation method of hard elastic polypropylene film, hard elastic polypropylene film and application |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN111098533A true CN111098533A (en) | 2020-05-05 |
| CN111098533B CN111098533B (en) | 2022-06-10 |
Family
ID=70426327
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201911419358.7A Active CN111098533B (en) | 2019-12-31 | 2019-12-31 | Preparation method of hard elastic polypropylene film, hard elastic polypropylene film and application |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN111098533B (en) |
Citations (13)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1276023A (en) * | 1968-08-30 | 1972-06-01 | Kalle Ag | Biaxially stretched film from polypropylene or copolymers or mixtures of polypropylene and polyethylene and process for the manufacture thereof |
| JPH05104619A (en) * | 1991-10-18 | 1993-04-27 | Mitsubishi Petrochem Co Ltd | Polypropylene low heat-shrinkable oriented tape and manufacture thereof |
| EP0872900A2 (en) * | 1997-04-15 | 1998-10-21 | Celgard Llc | Method of making a trilayer battery separator |
| CN101645498A (en) * | 2009-08-28 | 2010-02-10 | 深圳市星源材质科技股份有限公司 | Method for regulating and controlling formation of polyolefin microporous membrane and method for forming lithium cell separator |
| CN101695869A (en) * | 2009-10-30 | 2010-04-21 | 沧州明珠塑料股份有限公司 | Preparation method of polyolefin microporous film |
| US20110014408A1 (en) * | 2007-07-06 | 2011-01-20 | Idemitsu Unitech Co., Ltd | Polypropylene molded article, sheet-like polypropylene molded article, and method for production of polypropylene thermally molded article |
| CN102729532A (en) * | 2012-06-11 | 2012-10-17 | 达尼特材料科技（芜湖）有限公司 | Multilayer porous membrane and preparation method thereof |
| CN103819599A (en) * | 2012-11-16 | 2014-05-28 | 中国石油天然气股份有限公司 | Polypropylene resin for high-performance film and preparing method of polypropylene resin |
| CN104494157A (en) * | 2014-12-01 | 2015-04-08 | 深圳市星源材质科技股份有限公司 | Melt-spinning and cold-stretching preparation method of polyolefin microporous membrane and lithium battery membrane |
| CN105181733A (en) * | 2015-08-06 | 2015-12-23 | 江苏安瑞达新材料有限公司 | Method for simulation of polyolefin casting base membrane annealing treatment by DSC |
| CN105489813A (en) * | 2015-11-03 | 2016-04-13 | 深圳市星源材质科技股份有限公司 | Thermal treatment method for lithium battery diaphragm through dry method |
| CN106596624A (en) * | 2016-12-21 | 2017-04-26 | 深圳市星源材质科技股份有限公司 | Fractional crystallization analysis method of polyolefin resin |
| CN109742296A (en) * | 2018-12-28 | 2019-05-10 | 界首市天鸿新材料股份有限公司 | A kind of three-layer co-extruded lithium battery diaphragm and preparation method thereof |
-
2019
- 2019-12-31 CN CN201911419358.7A patent/CN111098533B/en active Active
Patent Citations (13)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1276023A (en) * | 1968-08-30 | 1972-06-01 | Kalle Ag | Biaxially stretched film from polypropylene or copolymers or mixtures of polypropylene and polyethylene and process for the manufacture thereof |
| JPH05104619A (en) * | 1991-10-18 | 1993-04-27 | Mitsubishi Petrochem Co Ltd | Polypropylene low heat-shrinkable oriented tape and manufacture thereof |
| EP0872900A2 (en) * | 1997-04-15 | 1998-10-21 | Celgard Llc | Method of making a trilayer battery separator |
| US20110014408A1 (en) * | 2007-07-06 | 2011-01-20 | Idemitsu Unitech Co., Ltd | Polypropylene molded article, sheet-like polypropylene molded article, and method for production of polypropylene thermally molded article |
| CN101645498A (en) * | 2009-08-28 | 2010-02-10 | 深圳市星源材质科技股份有限公司 | Method for regulating and controlling formation of polyolefin microporous membrane and method for forming lithium cell separator |
| CN101695869A (en) * | 2009-10-30 | 2010-04-21 | 沧州明珠塑料股份有限公司 | Preparation method of polyolefin microporous film |
| CN102729532A (en) * | 2012-06-11 | 2012-10-17 | 达尼特材料科技（芜湖）有限公司 | Multilayer porous membrane and preparation method thereof |
| CN103819599A (en) * | 2012-11-16 | 2014-05-28 | 中国石油天然气股份有限公司 | Polypropylene resin for high-performance film and preparing method of polypropylene resin |
| CN104494157A (en) * | 2014-12-01 | 2015-04-08 | 深圳市星源材质科技股份有限公司 | Melt-spinning and cold-stretching preparation method of polyolefin microporous membrane and lithium battery membrane |
| CN105181733A (en) * | 2015-08-06 | 2015-12-23 | 江苏安瑞达新材料有限公司 | Method for simulation of polyolefin casting base membrane annealing treatment by DSC |
| CN105489813A (en) * | 2015-11-03 | 2016-04-13 | 深圳市星源材质科技股份有限公司 | Thermal treatment method for lithium battery diaphragm through dry method |
| CN106596624A (en) * | 2016-12-21 | 2017-04-26 | 深圳市星源材质科技股份有限公司 | Fractional crystallization analysis method of polyolefin resin |
| CN109742296A (en) * | 2018-12-28 | 2019-05-10 | 界首市天鸿新材料股份有限公司 | A kind of three-layer co-extruded lithium battery diaphragm and preparation method thereof |
Non-Patent Citations (5)
| Title |
|---|
| LI, J ；SHANKS, RA ; LONG, Y: "Mechanical properties and morphology of polyethylene-polypropylene blends with controlled thermal history", 《JOURNAL OF APPLIED POLYMER SCIENCE》, vol. 76, no. 7, 16 May 2000 (2000-05-16), pages 1151 - 1164 * |
| 冯榕荫: "等规聚丙烯β-晶形研究的进展", 《绝缘材料》, no. 02, pages 48 - 53 * |
| 徐睿杰: "熔体拉伸流动场中聚合物的结晶行为及热处理过程研究", 《中国博士学位论文全文数据库》, 31 October 2015 (2015-10-31), pages 016 - 14 * |
| 曾胜、丁磊、许观、亢健、杨锋: "等规度和热处理对聚丙烯硬弹性膜力学性能的性能", 《高分子材料科学与工程》 * |
| 曾胜、丁磊、许观、亢健、杨锋: "等规度和热处理对聚丙烯硬弹性膜力学性能的性能", 《高分子材料科学与工程》, no. 6, 30 June 2017 (2017-06-30), pages 53 - 60 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN111098533B (en) | 2022-06-10 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN107331822B (en) | Polypropylene/polyethylene/polypropylene three-layer co-extrusion lithium ion battery diaphragm and preparation method thereof | |
| EP3960421B1 (en) | Device and method for preparing high-strength high-modulus polyolefin thin film, and high-strength high-modulus polyolefin thin film | |
| CN101695869B (en) | Preparation method of polyolefin microporous film | |
| CN109065817B (en) | Porous multilayer composite diaphragm and preparation method thereof | |
| CN104835930B (en) | A preparing method of a polyolefin microporous separating membrane | |
| CN103131080B (en) | Polypropylene microporous membrane and preparation method thereof | |
| CN102769115A (en) | Lithium ion battery membrane prepared by polypropylene mixture and preparing method thereof | |
| EP3428996B1 (en) | Method for preparing lithium-ion battery separator | |
| CN109935759B (en) | Preparation method of low-thermal-shrinkage battery diaphragm and battery diaphragm | |
| CN106981608B (en) | Preparation method of multilayer microporous membrane for lithium ion battery | |
| CN104494157A (en) | Melt-spinning and cold-stretching preparation method of polyolefin microporous membrane and lithium battery membrane | |
| KR20160015006A (en) | Manufacturing method with good productivity for preparing porous multilayered polyolefin | |
| CN111391267A (en) | Dry-process single-drawing production process of lithium battery diaphragm | |
| CN109742296B (en) | Three-layer co-extrusion lithium battery diaphragm and preparation method thereof | |
| CN111098533B (en) | Preparation method of hard elastic polypropylene film, hard elastic polypropylene film and application | |
| CN109728234B (en) | Lithium battery diaphragm with uniform aperture and preparation method thereof | |
| KR20190112362A (en) | Polyolefin microporous membrane | |
| CN103273654B (en) | The MIcroporous polyolefin film of a kind of ultra-thin method for preparing polyolefin microporous membrane and preparation thereof | |
| WO2013089033A1 (en) | Propylene-based resin microporous film, battery separator, battery and method for producing propylene-based resin microporous film | |
| CN106626457A (en) | Preparation method of polyolefin microporous membrane | |
| CN105181733A (en) | Method for simulation of polyolefin casting base membrane annealing treatment by DSC | |
| CN113809474B (en) | Polypropylene diaphragm, preparation method thereof and lithium ion battery | |
| CN103395153B (en) | A kind of method of low-temperature growth hard elastic polypropylene cast film | |
| CN107180939B (en) | Preparation method of lithium ion battery microporous membrane with uniform structure | |
| KR20170055038A (en) | Method of manufacturing battery separator |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |