Production method of PET composite current collector base film with high mechanical property

Abstract

The invention discloses a production method of a PET composite current collector base film with high mechanical property. The base film comprises an outer surface layer, a middle core layer and an inner surface layer, the outer surface layer is composed of PET, fumaric acid, hydroxyl-terminated polybutadiene and an antioxidant; the middle core layer consists of PET (Polyethylene Terephthalate), furandicarboxylic acid, an antioxidant and a stabilizer; the inner surface layer is composed of dimethyl terephthalate, ethylene glycol, spiro diol, ethylene glycol antimony and zinc acetate. The PET composite current collector base film prepared by the preparation method disclosed by the invention has relatively high mechanical properties.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of PET base film, in particular to a production method of PET composite current collector base film with high mechanical properties. BACKGROUND

[0002] Polyethylene terephthalate (PET) is prepared by ester exchange of dimethyl terephthalate and ethylene glycol or by esterification of terephthalic acid and ethylene glycol to synthesize bis-hydroxyethyl terephthalate, and then by polycondensation reaction. PET has the disadvantages of high transparency, strong chemical stability, and recyclability, but also has the disadvantages of weak crystallinity, brittleness, low elongation at break, and poor barrier property. SUMMARY

[0003] In view of the defects of the prior art, the purpose of the present application is to provide a production method of PET composite current collector base film with high mechanical properties.

[0004] To solve the above problems, the technical solution of the present application is: a production method of PET composite current collector base film with high mechanical properties, the base film comprising an outer surface layer, a middle core layer, and an inner surface layer; The outer surface layer is composed of PET, fumaric acid, hydroxyl-terminated polybutadiene, and antioxidant; The middle core layer is composed of PET, furan dicarboxylic acid, antioxidant, and stabilizer; The inner surface layer is composed of dimethyl terephthalate, ethylene glycol, spirodiol, antimony glycol, and zinc acetate; The production method comprises the following steps: (1) The raw materials are weighed according to the proportions of each component of the outer surface layer, the middle core layer, and the inner surface layer; (2) The raw materials of the inner surface layer are used to prepare spirodiol modified PET copolyester; (3) The raw materials of the outer surface layer and the middle core layer, and the prepared spirodiol modified PET copolyester, are sent to respective extruders for plasticizing and mixing; (3) The molten melts are respectively sent to the die head, and the melts are combined in the die head to form a molten sheet through the flat die head opening; (4) The sheet is attached to the chill roller by air knife for quenching to form an unformed sheet, and then the sheet is formed into a cast sheet after water bath cooling; (5) The cast sheet is stretched to form a film; (6) The film thickness is detected by infrared rays, and the corresponding thickness deviation is fed back to the die head, and the corresponding position screw bolt heating power is slightly moved to correct the film thickness deviation; (7) The film is wound.

[0005] Further, the components of the outer surface layer, the intermediate core layer and the inner surface layer are in a mass ratio of 20% for the outer surface layer, 60% for the intermediate core layer and 20% for the inner surface layer.

[0006] Further, the components of the intermediate core layer are in a mass ratio of 89.3% for PET, 10.5% for furandicarboxylic acid, 0.1% for antioxidant and 0.1% for stabilizer.

[0007] Further, the components of the inner surface layer are in a mass ratio of 38% for dimethyl terephthalate, 56.2% for ethylene glycol, 5.5% for spirodiol, 0.2% for antimony glycol and 0.1% for zinc acetate.

[0008] Further, the components of the outer surface layer are in a mass ratio of 87.9% for PET, 2% for fumaric acid, 10% for hydroxyl-terminated polybutadiene and 0.1% for antioxidant.

[0009] Further, the step (2) is specifically as follows: the dimethyl terephthalate, the ethylene glycol, the spirodiol and the zinc acetate of the inner surface layer are added into a container, heated to melt the raw materials under a nitrogen atmosphere, then the stirring is started, continuously heated to 215 DEG C, the low-boiling-point methanol is evaporated under the condensation reflux of hot water, the stirring is continuously started along with the evaporation of the methanol for 2 hours, then the antimony glycol is added, the temperature is increased to 265 DEG C, maintained for 2 hours, vacuumized to below 200 Pa, and the product, the spirodiol modified PET copolyester, is taken out after the reaction is completed.

[0010] The application has the following beneficial effects: the furandicarboxylic acid in the intermediate core layer is a modified monomer, the addition of the furandicarboxylic acid improves the tensile strength, the bending strength and the bending modulus of the PET, and the addition of the furandicarboxylic acid can improve the temperature resistance of the PET to a certain extent; The spirodiol in the inner surface layer has two symmetrical hydroxyl groups and four adjacent methyl-protected spiro rings in the molecular structure, has certain rigidity and good reactivity, can make the material obtain good heat resistance, toughness and high hardness and other physical properties, the addition of the spirodiol increases the rigidity of the polymer molecular main chain, is beneficial to the increase of the strength and the modulus of the polymer, and can also improve the thermal performance of the polyester; The hydroxyl-terminated polybutadiene in the outer surface layer is mixed with the PET to form a modified PET having oxygen absorption performance, has a good inhibitory effect on the oxygen permeation, the addition of the hydroxyl-terminated polybutadiene increases the molecular chain entanglement of the modified PET, the molecular chain entanglement causes the deformation to need greater external force, so the tensile strength, the bending strength and the breaking strength of the modified PET are gradually improved, that is, the mechanical properties are improved, the addition of the hydroxyl-terminated polybutadiene also makes the PET have good barrier properties; a small amount of fumaric acid is added to improve the impact strength of the PET, improve the mechanical properties, and greatly improve the water vapor transmission rate and the oxygen permeation rate. DETAILED DESCRIPTION

[0011] To provide a more intuitive and complete understanding of the technical solution of this invention, the following non-limiting features are described: A method for producing a high-mechanical-performance PET composite current collector base film, wherein the base film comprises an outer outer layer, an intermediate core layer, and an inner outer layer; The outer layer is composed of PET, fumaric acid, hydroxyl-terminated polybutadiene, and antioxidants; The intermediate core layer is composed of PET, furanyl dicarboxylic acid, antioxidants, and stabilizers; The inner surface layer is composed of dimethyl terephthalate, ethylene glycol, spirocyclohexane, antimony glycol, and zinc acetate; A method for producing a high-mechanical-performance PET composite current collector film includes the following steps: (1) Weigh the raw materials according to the proportions of each component in the outer layer, middle core layer and inner surface layer; (2) Prepare spirocyclic diol-modified PET copolyester using the raw materials of the inner surface layer; (3) The raw materials of the outer layer and the middle core layer, as well as the obtained spirocyclic glycol modified PET copolyester, are fed into their respective extruders for compounding and plasticizing. (3) The molten melt is fed into the die head separately. After the melt merges in the die head, it forms a molten sheet through the flat die head opening. (4) The sheet is attached to the cooling roller with an air knife and cooled rapidly to form an unshaped sheet. Then, the sheet is shaped into a cast sheet after being cooled in a water bath. (5) The cast sheet is stretched to form a thin film; (6) The film thickness is detected by infrared light and the corresponding thickness deviation is fed back to the die head. The thickness deviation of the film is corrected by micro-adjusting the heating power of the bolts at the corresponding positions. (7) Wind up the film.

[0012] The components of the outer layer, the middle core layer, and the inner surface layer are in the following mass ratio: outer layer 20%, middle core layer 60%, and inner surface layer 20%.

[0013] The components of the intermediate core layer by mass ratio are: PET 89.3%, furanyl dicarboxylic acid 10.5%, antioxidant 0.1%, and stabilizer 0.1%, with antioxidant being antioxidant 1010 and stabilizer being stabilizer 1098.

[0014] The components of the inner surface layer, by mass ratio, are: dimethyl terephthalate 38%, ethylene glycol 56.2%, spirocyclohexane 5.5%, antimony glycol 0.2%, and zinc acetate 0.1%.

[0015] The components of the outer layer by mass ratio are: 87.9% PET, 2% fumaric acid, 10% hydroxyl-terminated polybutadiene, and 0.1% antioxidant, which is antioxidant 1010.

[0016] Step (2) is as follows: Dimethyl terephthalate, ethylene glycol, spirodiol and zinc acetate from the inner surface are added to a container and heated under a nitrogen atmosphere until the raw materials melt. Stirring is then turned on and the mixture is heated to 215°C. The low-boiling-point methanol is evaporated under the reflux of hot water. Stirring is continued for 2 hours as the methanol evaporates. Then antimony glycol is added and the temperature is raised to 265°C and maintained for 2 hours. The vacuum is then drawn to below 200 Pa. After the reaction is completed, the product, spirodiol modified PET copolyester, is cooled and taken out.

[0017] The furanyl dicarboxylic acid in the middle core layer of this invention is a modified monomer. The addition of furanyl dicarboxylic acid improves the tensile strength, flexural strength and flexural modulus of PET, and the addition of furanyl dicarboxylic acid can improve the temperature resistance of PET to a certain extent. The spirocyclic diol molecule structure of the inner surface layer of this invention also contains two symmetrical hydroxyl groups and four adjacent methyl groups protecting the spiro ring, which has a certain rigidity and good reactivity. It can make the material obtain good physical properties such as heat resistance, toughness and high hardness. The addition of spirocyclic diol increases the rigidity of the polymer molecular backbone, which is beneficial to the increase of polymer strength and modulus, and can also improve the thermal properties of polyester. The present invention uses hydroxyl-terminated polybutadiene on the outer layer to blend with PET to form modified PET with oxygen absorption properties. It has a good inhibitory effect on oxygen permeation. The addition of hydroxyl-terminated polybutadiene increases the molecular chain entanglement of the modified PET. The molecular chain entanglement leads to the need for greater external force to deform, so its tensile strength, flexural strength and fracture strength are gradually improved, that is, its mechanical properties are improved. The addition of hydroxyl-terminated polybutadiene also makes the barrier properties of PET better. The addition of a small amount of fumaric acid can improve the impact strength of PET and improve its mechanical properties. The water vapor permeability and oxygen permeability are significantly improved.

Claims

1. A method for producing a high-mechanical-performance PET composite current collector film, characterized in that: The base film consists of an outer layer, a middle core layer, and an inner layer; The outer layer is composed of PET, fumaric acid, hydroxyl-terminated polybutadiene, and antioxidants; The intermediate core layer is composed of PET, furanyl dicarboxylic acid, antioxidants, and stabilizers; The inner surface layer is composed of dimethyl terephthalate, ethylene glycol, spirocyclohexane, antimony glycol, and zinc acetate; The production method includes the following steps: (1) Weigh the raw materials according to the proportions of each component in the outer layer, middle core layer and inner surface layer; (2) Prepare spirocyclic diol-modified PET copolyester using the raw materials of the inner surface layer; (3) The raw materials of the outer layer and the middle core layer, as well as the obtained spirocyclic glycol modified PET copolyester, are fed into their respective extruders for compounding and plasticizing. (3) The molten melt is fed into the die head separately. After the melt merges in the die head, it forms a molten sheet through the flat die head opening. (4) The sheet is attached to the cooling roller with an air knife and cooled rapidly to form an unshaped sheet. Then, the sheet is shaped into a cast sheet after being cooled in a water bath. (5) The cast sheet is stretched to form a thin film; (6) The film thickness is detected by infrared light and the corresponding thickness deviation is fed back to the die head. The thickness deviation of the film is corrected by micro-adjusting the heating power of the bolts at the corresponding positions. (7) Wind up the film.

2. The method for producing a high-mechanical-performance PET composite current collector film according to claim 1, characterized in that: The components of the outer layer, the middle core layer, and the inner surface layer are in the following mass ratio: outer layer 20%, middle core layer 60%, and inner surface layer 20%.

3. The method for producing a high-mechanical-performance PET composite current collector film according to claim 1, characterized in that: The components of the intermediate core layer are as follows by mass ratio: PET 89.3%, furanyl dicarboxylic acid 10.5%, antioxidant 0.1%, and stabilizer 0.1%.

4. The method for producing a high-mechanical-performance PET composite current collector film according to claim 1, characterized in that: The components of the inner surface layer, by mass ratio, are: dimethyl terephthalate 38%, ethylene glycol 56.2%, spirocyclohexane 5.5%, antimony glycol 0.2%, and zinc acetate 0.1%.

5. A method for producing a high-mechanical-performance PET composite current collector film according to claim 1, characterized in that: The outer layer consists of the following components by mass ratio: 87.9% PET, 2% fumaric acid, 10% hydroxyl-terminated polybutadiene, and 0.1% antioxidant.

6. A method for producing a high-mechanical-performance PET composite current collector film according to claim 1, characterized in that: Step (2) is as follows: Dimethyl terephthalate, ethylene glycol, spirodiol and zinc acetate from the inner surface are added to a container and heated under a nitrogen atmosphere until the raw materials melt. Stirring is then turned on and the mixture is heated to 215°C. The low-boiling-point methanol is evaporated under the reflux of hot water. Stirring is continued for 2 hours as the methanol evaporates. Then antimony glycol is added and the temperature is raised to 265°C and maintained for 2 hours. The vacuum is then drawn to below 200 Pa. After the reaction is completed, the product, spirodiol modified PET copolyester, is cooled and taken out.