Anti-static polyester film, preparation method and application

Abstract

The invention relates to the technical field of films, in particular to an anti-static polyester film, a preparation method and application. The anti-static polyester film comprises a polyester base material and an anti-static coating, wherein the anti-static coating comprises the following raw materials in parts by weight: 6-14 parts of modified waterborne polyester resin; 16-25 parts of a conductive polymer; 0.5 to 2 parts of a cross-linking agent; 0.05 to 0.2 part of a wetting agent; 50 to 70 parts of deionized water; the modified water-based polyester resin is prepared by condensation polymerization of an organosilicon intermediate, dibasic acid, polyol, a water-based monomer and a catalyst; the modified waterborne polyester resin is prepared from the following raw materials in parts by weight: 10-18 parts of an organosilicon intermediate; 22 to 30 parts of binary acid; 32 to 40 parts of polyol; 10-14 parts of a water-based monomer; and 0.1-0.3 part of a catalyst. The coating liquid is prepared from the organic silicon modified polyester resin and the water-based polythiophene dispersion liquid, a stable protective layer is formed on the surface during coating and film forming, an anti-static coating is endowed with excellent water resistance, and the prepared anti-static polyester film still keeps excellent anti-static and optical properties in a high-temperature and high-humidity environment.

Description

Technical Field

[0001] The invention relates to the technical field of films, and in particular to an antistatic polyester film, a preparation method and application thereof. Background Art

[0002] Optical devices or components are prone to static electricity during production, assembly, and transportation. The accumulation of static electricity can cause risks such as dust adsorption and circuit breakdown, so antistatic film is used for protection. However, the product may encounter harsh environments during transportation or storage, such as summer transportation, sea transportation, customs detention, etc. In a long-term high temperature and high humidity environment, water molecules can easily react with the hydrophilic groups in the antistatic coating through hydrogen bonds or cationic coordination, replacing some of the easily hydrolyzed chemical bonds between the coating and the substrate, thereby destroying the coating and causing a decrease in antistatic and optical properties. Therefore, it is necessary to develop an antistatic polyester film with excellent water resistance in a high temperature and high humidity environment.

[0003] Chinese patent CN114106387A provides an antistatic film, which is coated with epoxy resin modified polyester emulsion and water-based carbon nanotube dispersion to significantly improve the adhesion and antistatic performance of the antistatic film. However, the invention does not improve the water resistance, and the antistatic film is prone to performance degradation in high temperature and high humidity environments. Summary of the invention

[0004] In view of the shortcomings of the prior art, the purpose of the present invention can be achieved through the following technical solutions:

[0005] An antistatic polyester film comprises a polyester substrate and an antistatic coating, wherein the raw materials for preparing the antistatic coating comprise, by weight: 6-14 parts of modified waterborne polyester resin; 16-25 parts of conductive polymer; 0.5-2 parts of crosslinking agent; 0.05-0.2 parts of wetting agent; and 50-70 parts of deionized water; wherein the modified waterborne polyester resin is prepared by condensation polymerization of an organic silicon intermediate, a dibasic acid, a polyol, an aqueous monomer, and a catalyst; and the organic silicon intermediate, the dibasic acid, the polyol, the aqueous monomer, and the catalyst comprise, by weight: 10-18 parts of the organic silicon intermediate; 22-30 parts of the dibasic acid; 32-40 parts of the polyol; 10-14 parts of the aqueous monomer; and 0.1-0.3 parts of the catalyst.

[0006] Furthermore, the organosilicon intermediate contains at least one of silanol and silanol methoxy groups.

[0007] Furthermore, the dibasic acid is at least one of isophthalic acid, terephthalic acid, and adipic acid; and the polyol is at least one of neopentyl glycol, trimethylolpropane, and 1,4-cyclohexanedimethanol.

[0008] Furthermore, the aqueous monomer is at least one of sodium 5-sulfonate isophthalate and sodium 5-sulfonate dimethyl isophthalate; and the catalyst is at least one of tetrabutyl titanate and dibutyltin dilaurate.

[0009] Furthermore, the conductive polymer is a polythiophene aqueous dispersion, and the solid content of the polythiophene aqueous dispersion is 1-3%.

[0010] Furthermore, the cross-linking agent is at least one of polymelamine resin and polyisocyanate resin.

[0011] Furthermore, the wetting agent is at least one of polyether silicone and fluorocarbon polymer.

[0012] A method for preparing an antistatic polyester film, the preparation method comprising the following steps:

[0013] S1. Add polyol, dibasic acid and catalyst into a reactor, then introduce nitrogen and heat to 150°C for 1 hour, then gradually increase the temperature to 210°C and react for 2 hours, then add aqueous monomer to the reactor to react until the system is completely clarified;

[0014] S2, stop nitrogen input, start the vacuum pump, continue to heat up to 240 ° C, and when the melt shows the phenomenon of climbing the rod, the reaction is over; stepwise cool down to 100 ° C, add the organosilicon intermediate, and react for 1 hour; cool down to 60 ° C, add the catalyst and deionized water, disperse for 0.5 hours, and then filter to obtain the organosilicon-modified waterborne polyester resin;

[0015] S3. Add modified water-based polyester resin, conductive polymer, crosslinking agent, wetting agent and deionized water into a reaction container, and then use a high-speed shearing machine to fully stir for 30 minutes to obtain an antistatic coating liquid; evenly apply the prepared antistatic coating liquid on the surface of the polyester film to obtain an antistatic polyester film.

[0016] The above-mentioned antistatic polyester film is used as a protective material in optical equipment.

[0017] Beneficial effects of the present invention:

[0018] 1. The antistatic polyester film proposed by the present invention comprises a polyester substrate and an antistatic coating. The water-based resin in the antistatic coating is a water-based polyester resin modified by organic silicon. The polyester resin is modified by utilizing the characteristics of organic silicon having both organic and inorganic groups. The organic groups in the organic silicon help to be evenly dispersed in the resin during the polymerization process. The inorganic group silicon-oxygen bonds in the organic silicon have low surface energy and high bonding energy, and are enriched on the surface of the coating during film formation to form a Si-O-Si chain protective layer, giving the antistatic coating excellent water resistance.

[0019] 2. The coating liquid with prepared components of the antistatic layer in the antistatic polyester film proposed in the present invention is applied to the surface of the film and forms a stable network structure after thermal curing, which synergizes with the inorganic groups on the surface of the coating to effectively prevent water molecules from entering the interior of the coating, thereby further improving the water resistance of the antistatic coating.

[0020] 3. The antistatic polyester film prepared by the present invention has excellent water resistance and still maintains excellent antistatic and optical properties under high temperature and high humidity environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0022] Figure 1 It is a schematic diagram of the cross-sectional structure of the antistatic polyester film in the present invention.

[0023] The reference numerals in the figure represent: 1, antistatic coating, 2, polyester substrate layer. DETAILED DESCRIPTION

[0024] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0025] An antistatic polyester film comprises the polyester substrate and an antistatic coating, wherein the components of the antistatic coating are as follows in parts by weight:

[0026]

[0027] The components of the modified waterborne polyester resin are calculated by weight:

[0028]

[0029]

[0030] The organosilicon intermediate is selected from the brands DC3037 and DC6018 of Dow Corning and IC232 of Wacker. The silicon-oxygen bonds in the organosilicon have low surface energy and high bonding energy, and can form a protective layer rich in Si-O-Si bonds on the surface during film formation, effectively improving the water resistance of the coating. The addition amount of the organosilicon intermediate is 10-18 parts. When the addition amount of the organosilicon intermediate is less than 10 parts, the effect of improving the water resistance of the coating is not obvious. When the addition amount is more than 18 parts, the polyester particles will have a large particle size and are easy to aggregate and settle.

[0031] The dibasic acid is selected from at least one of isophthalic acid, terephthalic acid and adipic acid. The introduction of the aromatic acid can provide a rigid structure; adipic acid as an aliphatic acid can provide better flexibility, and the longer carbon chain can improve water resistance.

[0032] The polyol is selected from at least one of neopentyl glycol, trimethylolpropane and 1,4-cyclohexanedimethanol. The neopentyl glycol and trimethylolpropane molecular chains have multiple primary hydroxyl groups, and the ethyl or methyl groups on the molecular chains prevent the connected ester groups from being hydrolyzed due to the steric hindrance effect, thereby improving water resistance; 1,4-cyclohexanedimethanol has a symmetrical ring structure, which can provide certain rigidity and water resistance for polyester.

[0033] The water-based monomer is selected from at least one of 5-sodium sulfoisophthalate and 5-sodium dimethyl sulfoisophthalate. The sulfonate group in the water-based monomer contacts water as a hydrophilic group, thereby enhancing the solubility of the polyester resin in water. The amount of the water-based monomer added is 10-14 parts. When the amount of the water-based monomer added is less than 10 parts, the solubility of the polyester resin will be poor. When the amount of the water-based monomer added is more than 14 parts, the water resistance of the polyester resin will be affected.

[0034] The catalyst is selected from at least one of tetrabutyl titanate and dibutyltin dilaurate. The catalyst can improve the reaction rate in polyester synthesis, and the addition amount is 0.1-0.3 parts. When the addition amount of the catalyst is less than 0.1 parts, the catalytic effect is not obvious, and when the addition amount is more than 0.3 parts, the reaction will be too fast and difficult to control.

[0035] The synthesis process of the water-based polyester resin is as follows: add dibasic acid, polyol and catalyst to the reactor, heat to 150°C while continuously introducing N2, dissolve the material and keep warm for 1h, gradually heat to 210°C and carry out esterification reaction for 2h. When the system is clarified, add the water-based monomer and continue to react for 1h until the system is completely clarified. Turn on the vacuum pump and stop N2, continue to heat to 240°C to start the polycondensation reaction, and the reaction ends when the melt is slightly viscous and climbs the pole. Cool down to 100°C in a step-by-step manner, add the organosilicon intermediate, and keep warm for 1h. Continue to cool to below 60°C, add an appropriate amount of co-solvent to reduce the viscosity of the system, and finally add deionized water to disperse and adjust the solid content. After stirring and filtering, the organosilicon-modified water-based polyester resin is obtained.

[0036] The conductive polymer is a polythiophene aqueous dispersion, selected from Zanli Technology Company with the brand name ZPD-Y010 and Sno Fuhong Company with the brand name SN-ST-ES. As a conductive polymer material with excellent performance, the aqueous polythiophene dispersion can be stably dispersed in water and blended with water-based resin, and has the advantages of excellent optical properties, stable antistatic properties, and adjustable conductivity. The addition amount of the polythiophene aqueous dispersion is 16-25 parts. When the addition amount is less than 16 parts, the antistatic effect is not obvious. When the addition amount is more than 25 parts, there will be problems such as increased cost and easy precipitation.

[0037] The cross-linking agent is selected from the brand of Allnex Belgium Company, CYMEL-385, and the brand of Asahi Kasei Company, WSD20-70D. The cross-linking agent can react with the hydroxyl or carboxyl group in the resin, and form a dense network structure after thermal curing, which can effectively prevent water molecules from entering the coating, and further improve the water resistance of the antistatic coating. The amount of the cross-linking agent added is 0.5-2 parts. When the amount added is less than 0.5 parts, the cross-linking density is not enough, which will affect the water resistance. When the amount added is more than 2 parts, the curing agent will self-cross-link, and the components remaining in the coating after curing cannot volatilize, affecting the performance of the antistatic coating.

[0038] The wetting agent is selected from BYK346 of BYK Company and Zonyl-8867L of DuPont Company.

[0039] Example 1

[0040] Add 30 parts of neopentyl glycol, 6 parts of trimethylolpropane, 14 parts of isophthalic acid, 12 parts of adipic acid and 0.2 parts of tetrabutyl titanate to the reactor, heat to 150°C while continuously passing N2, keep warm for 1h, gradually heat to 210°C and react for 2h, add 12 parts of sodium 5-sulfonate isophthalic acid, and react for 1h until the system is completely clarified. Turn on the vacuum pump and stop N2, continue to heat to 240°C, and the reaction is over when the melt climbs the pole. Cool down to 100°C in a step-by-step manner, add 16 parts of DC3037, and react for 1h. Cool down to 60°C, add 10 parts of ethylene glycol monobutyl ether and 122 parts of deionized water, disperse for 0.5h, and filter to obtain a silicone-modified waterborne polyester resin.

[0041] 8 parts of modified waterborne polyester resin, 20 parts of ZPD-Y010, 1 part of CYMEL-385, 0.1 parts of BYK307, and 60 parts of deionized water were added to the reaction container, and the mixture was stirred for 30 minutes using a high-speed shearing machine to obtain an antistatic coating liquid. The prepared antistatic coating liquid was evenly coated on the surface of the polyester film to obtain the antistatic polyester film. The performance test results are shown in Table 1.

[0042] Example 2

[0043] Add 28 parts of neopentyl glycol, 4 parts of 1,4-cyclohexanedimethanol, 17 parts of terephthalic acid, 13 parts of adipic acid and 0.3 parts of dibutyltin dilaurate to the reactor, heat to 150°C while continuously passing N2, keep warm for 1h, gradually heat to 210°C and react for 2h, add 10 parts of sodium dimethyl isophthalate-5-sulfonate, react for 1h until the system is completely clarified. Turn on the vacuum pump and stop N2, continue to heat to 240°C, and the reaction is over when the melt climbs the pole. Cool down to 100°C in a step-by-step manner, add 18 parts of DC6018, and react for 1h. Cool down to 60°C, add 12 parts of ethylene glycol monobutyl ether and 123 parts of deionized water, disperse for 0.5h, and filter to obtain a silicone-modified waterborne polyester resin.

[0044] Add 10 parts of modified waterborne polyester resin, 16 parts of SN-ST-ES, 2 parts of WSD20-70D, 0.2 parts of Zonyl-8867L, and 50 parts of deionized water into a reaction container, and stir them thoroughly for 30 minutes using a high-speed shearing machine to obtain an antistatic coating liquid. The prepared antistatic coating liquid is evenly coated on the surface of the polyester film to obtain the antistatic polyester film. The performance test results are shown in Table 1.

[0045] Example 3

[0046] Add 30 parts of trimethylolpropane, 10 parts of 1,4-cyclohexanedimethanol, 12 parts of terephthalic acid, 10 parts of isophthalic acid, 0.2 parts of tetrabutyl titanate and 0.8 parts of dibutyltin dilaurate to the reactor, heat to 150°C while continuously passing N2, keep warm for 1h, gradually heat to 210°C and react for 2h, add 8 parts of sodium 5-sulfonate isophthalic acid and 6 parts of dimethyl 5-sulfonate isophthalate, react for 1h until the system is completely clarified. Turn on the vacuum pump and stop N2, continue to heat to 240°C, and the reaction is over when the melt climbs the pole. Cool down to 100°C in a step-by-step manner, add 10 parts of IC232, and react for 1h. Cool down to 60°C, add 10 parts of ethylene glycol monobutyl ether and 119 parts of deionized water, disperse for 0.5h, and filter to obtain a silicone-modified waterborne polyester resin.

[0047] Add 6 parts of modified waterborne polyester resin, 8 parts of ZPD-Y010 and 17 parts of SN-ST-ES, 0.3 parts of CYMEL-385 and 0.2 parts of WSD20-70D, 0.01 parts of BYK-346 and 0.04 parts of Zonyl-8867L, and 70 parts of deionized water into the reaction container, and stir them thoroughly for 30 minutes using a high-speed shearing machine to obtain an antistatic coating liquid. The prepared antistatic coating liquid is evenly coated on the surface of the polyester film to obtain the antistatic polyester film. The performance test results are shown in Table 1.

[0048] Example 4

[0049] Add 20 parts of neopentyl glycol, 10 parts of trimethylolpropane, 8 parts of 1,4-cyclohexanedimethanol, 10 parts of terephthalic acid, 5 parts of isophthalic acid, 9 parts of adipic acid, 0.9 parts of tetrabutyl titanate and 0.6 parts of dibutyltin dilaurate to the reactor, heat to 150°C while continuously passing N2, keep warm for 1h, gradually heat to 210°C and react for 2h, add 11 parts of sodium 5-sulfonate isophthalic acid, react for 1h until the system is completely clarified. Turn on the vacuum pump and stop N2, continue to heat to 240°C, and the reaction is over when the melt climbs the pole. Cool down to 100°C in a step-by-step manner, add 8 parts of DC3037 and 4 parts of IC232, and react for 1h. Cool down to 60°C, add 12 parts of ethylene glycol monobutyl ether and 115 parts of deionized water, disperse for 0.5h, and filter to obtain a silicone-modified waterborne polyester resin.

[0050] 7 parts of modified waterborne polyester resin, 15 parts of ZPD-Y010 and 8 parts of SN-ST-ES, 0.25 parts of CYMEL-385 and 0.5 parts of WSD20-70D, 0.05 parts of BYK-346 and 0.02 parts of Zonyl-8867L, and 65 parts of deionized water were added to the reaction container, and the mixture was stirred for 30 minutes using a high-speed shearing machine to obtain an antistatic coating liquid. The prepared antistatic coating liquid was evenly coated on the surface of the polyester film to obtain the antistatic polyester film. The performance test results are shown in Table 1.

[0051] Example 5

[0052] Add 34 parts of neopentyl glycol, 28 parts of isophthalic acid and 0.25 parts of tetrabutyl titanate to the reactor, heat to 150°C while continuously passing N2, keep warm for 1h, gradually heat to 210°C and react for 2h, add 13 parts of dimethyl isophthalate-5-sodium sulfonate, react for 1h until the system is completely clarified. Turn on the vacuum pump and stop N2, continue to heat to 240°C, and the reaction is over when the melt climbs the pole. Cool down to 100°C in a step-by-step manner, add 6 parts of DC3037 and 10 parts of IC232, and react for 1h. Cool down to 60°C, add 13 parts of ethylene glycol monobutyl ether and 122 parts of deionized water, disperse for 0.5h, and filter to obtain a silicone-modified waterborne polyester resin.

[0053] Add 9 parts of modified waterborne polyester resin, 8 parts of ZPD-Y010 and 10 parts of SN-ST-ES, 1.5 parts of WSD20-70D, 0.15 parts of Zonyl-8867L, and 55 parts of deionized water into the reaction container, and stir them thoroughly for 30 minutes using a high-speed shearing machine to obtain an antistatic coating liquid. The prepared antistatic coating liquid is evenly coated on the surface of the polyester film to obtain the antistatic polyester film. The performance test results are shown in Table 1.

[0054] Comparative Example 1

[0055] No silicone-modified polyester resin was added, and other conditions were the same as in Example 1. The performance test results are shown in Table 1.

[0056] Comparative Example 2

[0057] Commercially available polyester resin EW370 (SK company product) was used, and other conditions were the same as in Example 1. The performance test results are shown in Table 1.

[0058] The performance test results are shown in Table 1. The performance test methods in the table are as follows:

[0059] (1) Surface resistivity test of antistatic polyester film: refer to GB / T 33398.

[0060] (2) Optical performance test: refer to GB / T 2410-2008.

[0061] (3) Water resistance test: The prepared antistatic film was cut into 10*10 cm pieces and placed in 60°C deionized water for 1 hour, and then the surface resistance and optical properties were tested.

[0062] Table 1 Performance test results of antistatic polyester films prepared in Examples 1-5 and Comparative Examples 1-2

[0063]

[0064] It can be seen from the table that the antistatic polyester film of the present invention has excellent water resistance and still maintains excellent antistatic and optical properties after being subjected to a high temperature and high humidity environment. From the comparison between the above comparative examples 1 and 2 and the embodiment, it can be seen that the antistatic performance of the waterborne polyester resin not modified with silicone and the commercially available waterborne polyester resin after being subjected to a high temperature and high humidity environment is greatly reduced; the test haze becomes larger, the film surface appears white, and the optical properties deteriorate. The water resistance is thus quite different from that of the present invention, which also proves the excellence of the technical solution of the present invention from another aspect.

[0065] In the description of this specification, the description with reference to the terms "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0066] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments, and the above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, and these changes and improvements all fall within the scope of the present invention to be protected.

Claims

1. An antistatic polyester film, comprising a polyester substrate and an antistatic coating, characterized in that: The raw materials for preparing the antistatic coating include, by weight: 6-14 parts of modified water-based polyester resin; 16-25 parts of conductive polymer; 0.5-2 parts of cross-linking agent; 0.05-0.2 parts of wetting agent; 50-70 parts of deionized water; wherein the modified water-based polyester resin is prepared by condensation polymerization of an organic silicon intermediate, a dibasic acid, a polyol, an aqueous monomer, and a catalyst; the organic silicon intermediate, the dibasic acid, the polyol, the aqueous monomer, and the catalyst are calculated by weight as follows: 10-18 parts of the organic silicon intermediate; 22-30 parts of the dibasic acid; 32-40 parts of the polyol; 10-14 parts of the aqueous monomer; and 0.1-0.3 parts of the catalyst.

2. The antistatic polyester film according to claim 1, characterized in that: The organosilicon intermediate contains at least one of silanol and silanol methoxy groups.

3. The antistatic polyester film according to claim 1, characterized in that: The dibasic acid is at least one of isophthalic acid, terephthalic acid and adipic acid; the polyol is at least one of neopentyl glycol, trimethylolpropane and 1,4-cyclohexanedimethanol.

4. The antistatic polyester film according to claim 1, characterized in that: The aqueous monomer is at least one of sodium 5-sulfoisophthalate and sodium 5-sulfoisophthalate dimethyl ester; the catalyst is at least one of tetrabutyl titanate and dibutyltin dilaurate.

5. The antistatic polyester film according to claim 1, characterized in that: The conductive polymer is a polythiophene aqueous dispersion, and the solid content of the polythiophene aqueous dispersion is 1-3%.

6. The antistatic polyester film according to claim 1, characterized in that: The cross-linking agent is at least one of polymelamine resin and polyisocyanate resin.

7. The antistatic polyester film according to claim 1, characterized in that: The wetting agent is at least one of polyether silicone and fluorocarbon polymer.

8. The method for preparing an antistatic polyester film according to any one of claims 1 to 7, characterized in that: The preparation method comprises the following steps: S1. Add polyol, dibasic acid and catalyst into a reactor, then introduce nitrogen and heat to 150°C for 1 hour, then gradually increase the temperature to 210°C and react for 2 hours, then add aqueous monomer to the reactor to react until the system is completely clarified; S2, stop nitrogen input, start the vacuum pump, continue to heat up to 240 ° C, and when the melt shows the phenomenon of climbing the rod, the reaction is over; stepwise cool down to 100 ° C, add the organosilicon intermediate, and react for 1 hour; cool down to 60 ° C, add the catalyst and deionized water, disperse for 0.5 hours, and then filter to obtain the organosilicon-modified waterborne polyester resin; S3. Add modified water-based polyester resin, conductive polymer, crosslinking agent, wetting agent and deionized water into a reaction container, and then use a high-speed shearing machine to fully stir for 30 minutes to obtain an antistatic coating liquid; evenly apply the prepared antistatic coating liquid on the surface of the polyester film to obtain an antistatic polyester film.

9. Use of the antistatic polyester film as claimed in any one of claims 1 to 7 as a protective material in optical equipment.

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