Bopp protective film and its application on electronic products

Abstract

The application relates to the technical field of BOPP films, in particular to a BOPP protective film and application of the BOPP protective film to electronic products. The BOPP protective film is prepared by adding tin-antimony oxide coated titanium dioxide whiskers modified by an amino silane coupling agent as an antistatic agent and maleic anhydride grafted polypropylene as a compatibilizer into a surface layer material of the BOPP protective film; the antistatic agent is effectively dispersed on the surface layer and overlaps with each other; the surface resistivity of the BOPP protective film is significantly reduced; the continuity of the BOPP protective film is enhanced by using the moisture absorption and adhesion of a polydopamine layer; a conductive network is constructed through multiple connection anchoring; the environmental adaptability is improved; and the antistatic durability is enhanced. The prepared BOPP protective film has excellent physical and mechanical properties, low surface resistivity, long antistatic performance timeliness, and is suitable for electronic products.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of BOPP films, and particularly relates to a BOPP protective film and application thereof to electronic products. BACKGROUND

[0002] BOPP film is a kind of film made of biaxially oriented polypropylene material, which is widely used in food packaging, electronic product packaging, printing and other fields due to its excellent transparency, gloss, moisture resistance, barrier property and mechanical property. However, with the increasing demand for packaging, higher requirements are put forward for the performance of BOPP film. At present, the demand for BOPP film in the market is increasing, but the existing BOPP film still has some shortcomings in some performances. For example, in the field of electronic products, electronic products are extremely sensitive to static electricity, and static discharge may cause component failure. However, polypropylene is an insulating material, which is easy to accumulate static electricity. Therefore, anti-static treatment is needed to meet the needs of the electronic industry.

[0003] BOPP needs to be treated by anti-static treatment to make the surface resistance lower than 10 11 Ω. However, the following problems may occur during the anti-static treatment process: (1) the anti-static agent is not uniformly dispersed in the BOPP substrate, and the uneven thickness of the coating layer leads to uneven anti-static effect; (2) the anti-static agent migrated to the surface is lost due to external friction and temperature change, and the anti-static coating is invalid due to environmental humidity reduction or oxidation, finally leading to poor anti-static performance timeliness; (3) the BOPP substrate surface has low polarity, and the compatibility with the polar anti-static coating is poor, which easily leads to coating peeling and static accumulation; (4) part of the anti-static agent or coating is not uniformly dispersed, forming small particles in the BOPP film, which leads to a decrease in light scattering transparency. SUMMARY

[0004] In view of the above problems, the application provides a BOPP protective film and application thereof to electronic products.

[0005] The application first provides a BOPP protective film.

[0006] A BOPP protective film is prepared by the following steps: S1, mixing and extruding polypropylene and a slip agent as a core layer material; S2, mixing and extruding polypropylene, maleic anhydride grafted polypropylene and an antistatic agent as a surface layer material; S3, melting the core layer material in a main extruder, melting the surface layer material in two auxiliary extruders, extruding through a die, and then bidirectional stretching to obtain a BOPP film; S4, carrying out corona treatment on the BOPP film to obtain a BOPP corona film; S5, immersing the BOPP corona film in a hydrophilic antistatic prepolymer solution to make the surface of the BOPP corona film have a hydrophilic antistatic layer, and obtaining the BOPP protective film; the antistatic agent in S2 is 1-3% by mass of the polypropylene, and the addition amount of the maleic anhydride grafted polypropylene is 0.5-1.2% by mass of the polypropylene.

[0007] Further, the antistatic agent is prepared by the following steps: (1) adding antimony acetate and tin chloride into ethanol, then slowly adding ethyl acetoacetate, stirring until clear, and obtaining a precursor solution; (2) slowly adding the precursor solution into a titanium dioxide whisker suspension, heating and reacting until the solvent is completely evaporated, then calcining, grinding, sieving, and obtaining conductive whiskers; (3) ultrasonic dispersing the conductive whiskers into anhydrous ethanol, then reacting with an amino silane hydrolysate to obtain uniformly dispersed antistatic agents.

[0008] Further, the molar amount ratio of antimony acetate, tin chloride and ethyl acetoacetate is (0.07-0.09):1:(1.1-1.2).

[0009] Further, the mass amount ratio of the titanium dioxide whisker and tin chloride is (1.3-1.5):4; the heating reaction temperature is 90-100℃, and the calcination temperature is 450-600℃.

[0010] Further, the amino silane coupling agent is 2-6wt% of the mass of the conductive whisker; and the preparation method of the amino silane hydrolysate is: adding the amino silane coupling agent into an ethanol aqueous solution, mixing uniformly, adjusting the solution to be weakly acidic with dilute hydrochloric acid, and stirring until the solution is transparent.

[0011] Further, the diameter of the titanium dioxide whisker is less than 40nm.

[0012] Further, the amino silane coupling agent is one of γ-aminopropyltrimethoxysilane, γ-aminopropyltriisopropoxysilane and γ-aminopropyltriethoxysilane.

[0013] Further, the power of the corona treatment is 1-2kW.

[0014] Further, the preparation method of the hydrophilic antistatic prepolymer solution is as follows: dopamine is dissolved in deionized water, then dextran-phenyl boronic acid solution is added, and then tris-hydroxymethyl aminomethane is added to adjust the pH value to 8-9; the concentration of dopamine in the hydrophilic antistatic prepolymer solution is 0.02-0.04 g / L, and the mass ratio of dextran-phenyl boronic acid to dopamine is (0.5-0.8) : 1.

[0015] The application also provides an application of the BOPP protective film on electronic products, and the BOPP protective film prepared by the above preparation method can be used for electronic component packaging, battery packaging and electronic product outer packaging.

[0016] Compared with the prior art, the application has the following beneficial effects:

[0017] 1. The application takes the antistatic agent as the core conductive path, takes the polydopamine layer as the auxiliary, utilizes the moisture absorption and adhesion to enhance the continuity, cooperatively constructs the conductive network, improves the environmental adaptability, anchors through multiple connections, and enhances the antistatic durability.

[0018] 2. The application takes the titanium dioxide whisker coated with tin-antimony oxide modified by amino silane coupling agent as the antistatic agent, takes maleic anhydride grafted polypropylene as the compatibilizer, directly adds the antistatic agent into the surface layer material of the BOPP protective film, and the antistatic agent is effectively dispersed on the surface and overlaps with each other, so that the surface resistivity of the BOPP protective film is significantly reduced.

[0019] 3. The BOPP protective film prepared by the application has excellent physical and mechanical properties, low surface resistivity, long antistatic performance timeliness, and is suitable for electronic products. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 It is a surface resistivity comparison diagram of the BOPP protective film of the application.

[0021] Figure 2 It is a surface SEM diagram of the BOPP protective film of the application.

[0022] Figure 3 It is an antistatic durability test diagram of the BOPP protective film of the application. DETAILED DESCRIPTION

[0023] In order to make the application purpose, technical scheme and beneficial technical effects of the application clearer, the application is further described in detail below in combination with embodiments, and other advantages and effects of the application can be easily understood by those skilled in the art from the disclosed content.

[0024] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in the description herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0025] In the case using "comprise", "have", and "include" described herein, it is intended to cover the inclusions without exclusions, unless the explicit limiting terms such as "only", "consist of", etc. are used, another component can be added.

[0026] The words "preferably", "more preferably", "most preferably", "particularly", "more particularly", "particularly preferably", and "most particularly preferably" in the specification, examples and appended claims of this application are used to describe embodiments of the application that are preferred or particularly advantageous. However, these words are not used to limit or restrict the scope of the application in any way. The words "preferably", "more preferably", "most preferably", "particularly", "more particularly", "particularly preferably", and "most particularly preferably" in the specification, examples and appended claims of this application are used to describe embodiments of the application that are preferred or particularly advantageous. However, these words are not used to limit or restrict the scope of the application in any way.

[0027] In the specification, examples and appended claims of this application, the words "further", "more", "especially" and "particularly" are used to describe a feature that is in addition to another feature or features. Such words are not used to limit or restrict the scope of the application in any way.

[0028] In the specification, examples and appended claims of this application, the expression "at least one" means one or more, e.g. one, two or more. The expression "a plurality of" or "several" means at least two, e.g. two, three or more. The expression "a plurality of" or "several" means at least two, e.g. two, three or more, unless expressly specified otherwise. In the specification, examples and appended claims of this application, the expression "a number of means at least one, e.g. one, two or more, unless expressly specified otherwise.

[0029] When a numerical range is disclosed herein, the range is to be construed as having been recited continuously, and including the minimum and maximum values of the range, as well as every value between the minimum and maximum values. Further, when ranges are provided, the ranges can be combined. In other words, unless otherwise indicated, all ranges disclosed herein are to be understood as encompassing any and all sub-ranges subsumed therein. For example, a range of "1 to 10" is to be construed as including any and all sub-ranges between (and including) the minimum value of 1 and the maximum value of 10; that is, all sub-ranges beginning with a minimum value of 1 or more and ending with a maximum value of 10 or less, as well as every number of the range. Further, a range of "about 1 to 10" is to be construed as including any and all sub-ranges subsumed therein; for example, a range of "about 1 to 4.5", or a range of "about 3.5 to 10", or a range of "about 4 to 5.5", or a range of "about 8 to 10", etc.

[0030] If not otherwise specified, all steps of the present application can be performed in sequence or randomly. For example, the method comprises steps (a) and (b), which means that the method can comprise steps (a) and (b) performed in sequence, or steps (b) and (a) performed in sequence. For example, the method is mentioned to further comprise step (c), which means that step (c) can be added to the method in any sequence, for example, the method can comprise steps (a), (b) and (c), or steps (a), (c) and (b), or steps (c), (a) and (b), etc. Unless otherwise mentioned, the singular form of the term can include the plural form and cannot be understood as one in number.

[0031] The present application is directed to the defects of the conventional antistatic agent added in the existing BOPP film, such as poor compatibility with polypropylene, easy agglomeration, or wear or oxidation in the migration process, limited surface resistivity, etc., which is difficult to meet the ultra-static sensitive scene of electronic products. After a large number of experimental researches, a BOPP protective film is provided, in which tin-antimony oxide is coated on titanium dioxide whiskers, and then modified with an amino silane coupling agent to obtain an antistatic agent, which is directly added to the surface layer material of the BOPP protective film, and maleic anhydride grafted polypropylene is added to further improve the compatibility of the antistatic agent with the polypropylene matrix. The antistatic agent is effectively dispersed on the surface layer and overlaps with each other, so that it can form a complete conductive path through mutual contact and tunneling effect, thereby reducing the surface resistivity. In order to further reduce the surface resistivity of the BOPP protective film, the surface of the BOPP protective film is first treated by corona treatment, and then a polydopamine hydrophilic layer coating is loaded. The amino group of the silane coupling agent reacts with the active groups in the polydopamine, so that the polydopamine layer not only adheres to the BOPP corona surface, but also combines with the antistatic agent to form multiple connection anchors, reducing the risk of polydopamine layer falling off. The catechol group in the molecular chain has strong hygroscopicity, which can adsorb moisture in the air to form a conductive channel. The antistatic agent provides a core conductive path, and the polydopamine layer enhances the continuity thereof through hygroscopic and adhesive effects, cooperatively constructs a conductive network, and improves the environmental adaptability. The chemical stability of the polydopamine hydrophilic layer can also protect the surface layer antistatic agent from being eroded by water vapor and ultraviolet light, and enhance the antistatic durability.

[0032] Example 1

[0033] A BOPP protective film is prepared by the following steps:

[0034] S1, polypropylene (homopolymer polypropylene) 8 kg, slip agent (erucic acid amide) is mixed and extruded according to the mass ratio of 8:0.05 as the core layer material;

[0035] S2, polypropylene (homopolymer polypropylene) 8 kg, maleic anhydride grafted polypropylene (grafting rate 1%), antistatic agent were mixed and extruded according to the mass ratio 8:0.04:0.08, as the surface layer material;

[0036] S3, the core layer material was melted in the main extruder, the surface layer material was respectively placed in two auxiliary extruders and melted, the melt passed through the filter screen to remove impurities, then was extruded through the die to form a sheet melt curtain, was rapidly cooled, then was bidirectional stretched, the longitudinal stretching temperature was 110℃, the longitudinal stretching ratio was 4.5; the transverse stretching temperature was 150, the transverse stretching ratio was 8, then was heat set, cooled, pulled, edge cut, rolled, and slitted to obtain the BOPP film;

[0037] S4, the BOPP film was subjected to corona treatment, the power of the corona treater was 1kW, to obtain the BOPP corona film;

[0038] S5, the BOPP corona film was sequentially ultrasonically cleaned with ethanol and water to remove surface impurities, then was pre-wetted with ethanol for 20min, then was immersed in the hydrophilic antistatic pre-polymerization solution, and was kept at room temperature for 10h, so that the dopamine polymerization reaction was carried out, a polydopamine hydrophilic antistatic layer was formed and fixed on the surface of the corona film, then the BOPP corona film was taken out, was cleaned with ethanol and water alternately to remove residual chemicals, then was dried at 60℃ for 3h to obtain the BOPP protective film.

[0039] In the embodiment, the preparation method of the hydrophilic antistatic pre-polymerization solution was as follows: dopamine was dissolved in deionized water, then dextran-phenylboric acid solution was added, and then tris-hydroxymethyl aminomethane was added to adjust the pH value to 8; the concentration of dopamine in the hydrophilic antistatic pre-polymerization solution was 0.02g / L, and the mass ratio of dextran-phenylboric acid to dopamine was 0.5:1.

[0040] In the embodiment, the antistatic agent was prepared by the following steps:

[0041] (1) antimony acetate 0.07mol and tin chloride 1mol were added into ethanol 150mL, then ethyl acetoacetate 1.1mol was slowly added dropwise, and the mixture was stirred until clear to obtain a precursor solution;

[0042] (2) the precursor solution was slowly added dropwise into a titanium dioxide whisker suspension, heated to 90℃, and stirred to react until the solvent was completely evaporated, then calcined at 450℃ for 3h, ground, and sieved through a 200 mesh screen to obtain the conductive whisker; the mass dosage ratio of the titanium dioxide whisker to the tin chloride was 1.3:4; the titanium dioxide whisker suspension was obtained by ultrasonic dispersion of the titanium dioxide whisker in deionized water at 65℃, and the concentration of the titanium dioxide whisker in the titanium dioxide whisker suspension was 0.5g / L.

[0043] (3) 1 g of the conductive whisker was ultrasonically dispersed in 350 mL of anhydrous ethanol, and then reacted with an amino silane hydrolysate to obtain an antistatic agent uniformly dispersed. The amino silane hydrolysate was prepared by the following method: 20 mL of an ethanol aqueous solution (the volume ratio of ethanol to water in the ethanol aqueous solution was 3:1) was added with γ-aminopropyltrimethoxysilane (the mass of the γ-aminopropyltrimethoxysilane was 2% of the mass of the conductive whisker), and then mixed uniformly. The pH of the solution was adjusted to 5 with 0.1 mol / L dilute hydrochloric acid, and the solution was stirred until it became transparent.

[0044] In this embodiment, the diameter of the titanium dioxide whisker is less than 40 nm.

[0045] In this embodiment, the titanium dioxide whisker can be obtained by the following method: (1) 10 mL of tetrabutyl titanate was dissolved in 30 mL of anhydrous ethanol, and then magnetically stirred for 15 min to obtain a titanium source solution; (2) 15 g of sodium hydroxide was dissolved in 35 mL of water, and then slowly added dropwise to the titanium source solution while stirring vigorously until a precursor suspension was formed; (3) the precursor suspension was sealed at 150°C for 12 h, naturally cooled to room temperature, then centrifuged, and the bottom precipitate was collected, washed repeatedly with water and ethanol, vacuum dried, and then calcined at 500°C for 2.5 h to obtain the titanium dioxide whisker.

[0046] Example 2

[0047] A BOPP protective film was prepared by the following steps:

[0048] S1, polypropylene (homopolymer polypropylene) 8 kg, slip agent (erucic acid amide) were mixed and extruded as core layer material according to a mass ratio of 8:0.05;

[0049] S2, polypropylene (homopolymer polypropylene) 8 kg, maleic anhydride grafted polypropylene (grafting rate 1%), and antistatic agent were mixed and extruded as surface layer material according to a mass ratio of 8:0.064:0.16;

[0050] S3, the core layer material was melted in the main extruder, and the surface layer material was melted in two auxiliary extruders respectively. After removing impurities through the filter screen, the melt was extruded through the die to form a sheet-shaped melt curtain, which was then rapidly cooled and then bidirectionally stretched. The longitudinal stretching temperature was 125°C, and the longitudinal stretching ratio was 5. The transverse stretching temperature was 160°C, and the transverse stretching ratio was 9. Then, the BOPP film was obtained after heat setting, cooling treatment, traction, edge cutting, winding, and slitting.

[0051] S4, the BOPP film was subjected to corona treatment, and a BOPP corona film was prepared with a power of 1.5 kW of the corona treater.

[0052] S5, the BOPP corona film was sequentially cleaned with ethanol and water by ultrasonic to remove surface impurities, then pre-wetted with ethanol for 20 min, then immersed in the hydrophilic antistatic pre-polymerization solution, kept at room temperature for 14 h, so that the dopamine polymerization reaction was carried out to form a polydopamine hydrophilic antistatic layer fixed on the surface of the corona film, then the BOPP corona film was taken out, cleaned with ethanol and water alternately to remove residual chemicals, and then dried at 60℃ for 3 h to obtain the BOPP protective film.

[0053] In this embodiment, the preparation method of the hydrophilic antistatic pre-polymerization solution is as follows: dopamine is dissolved in deionized water, then dextran-phenylboric acid solution is added, and then trimethylaminomethane is added to adjust the pH value to 9; the concentration of dopamine in the hydrophilic antistatic pre-polymerization solution is 0.03 g / L, and the mass ratio of dextran-phenylboric acid to dopamine is 0.6:1.

[0054] In this embodiment, the antistatic agent is prepared by the following steps:

[0055] (1) 0.08 mol of antimony acetate and 1 mol of tin chloride are added to 150 mL of ethanol, then 1.2 mol of ethyl acetoacetate is slowly added dropwise, and stirred until clear to obtain a precursor solution;

[0056] (2) The precursor solution is slowly added to a titanium dioxide whisker suspension, heated to 95℃, and stirred to react until the solvent is completely evaporated, then calcined at 500℃ for 3 h, ground, and sieved through a 200 mesh screen to obtain conductive whiskers; the mass ratio of titanium dioxide whiskers to tin chloride is 1.4:4; the titanium dioxide whisker suspension is obtained by ultrasonic dispersion of titanium dioxide whiskers in deionized water at 65℃, and the concentration of titanium dioxide whiskers in the titanium dioxide whisker suspension is 0.8 g / L.

[0057] (3) 1.2 g of conductive whiskers is ultrasonically dispersed in 450 mL of anhydrous ethanol, then reacted with an amino silane hydrolysate to obtain uniformly dispersed antistatic agent. The preparation method of the amino silane hydrolysate is as follows: γ-aminopropyl triisopropoxy silane (γ-aminopropyl triisopropoxy silane is 4 wt% of the mass of the conductive whiskers) is added to 25 mL of an ethanol aqueous solution (the volume ratio of ethanol to water in the ethanol aqueous solution is 3:1), mixed uniformly, and then the pH of the solution is adjusted to 4 with 0.1 mol / L dilute hydrochloric acid, and stirred until the solution is transparent.

[0058] In this embodiment, the diameter of the titanium dioxide whiskers is less than 40 nm.

[0059] Example 3

[0060] A BOPP protective film is prepared by the following steps:

[0061] S1, polypropylene (homopolymer polypropylene) 8 kg, slip agent (erucamide) were mixed and extruded as core layer material according to the mass ratio of 8:0.05;

[0062] S2, polypropylene (homopolymer polypropylene) 8 kg, maleic anhydride grafted polypropylene (grafting rate of 1%), antistatic agent were mixed and extruded as surface layer material according to the mass ratio of 8:0.096:0.24;

[0063] S3, the core layer material was melted in the main extruder, and the surface layer material was melted in two auxiliary extruders respectively. After removing impurities through the filter screen, the melt was extruded through the die to form a sheet melt curtain, which was rapidly cooled and then bidirectionally stretched. The longitudinal stretching temperature was 145℃, and the longitudinal stretching ratio was 6. The transverse stretching temperature was 170℃, and the transverse stretching ratio was 10. Then, the BOPP film was obtained through heat setting, cooling treatment, traction, edge cutting, winding, and slitting.

[0064] S4, the BOPP film was subjected to corona treatment with a power of 2kW to obtain a BOPP corona film;

[0065] S5, the BOPP corona film was sequentially ultrasonically cleaned with ethanol and water to remove surface impurities, then pre-wetted with ethanol for 20min, and then immersed in a hydrophilic antistatic pre-polymerization solution for 18h at room temperature to allow dopamine polymerization and form a polydopamine hydrophilic antistatic layer fixed on the surface of the corona film. Then, the BOPP corona film was taken out and cleaned with ethanol and water alternately to remove residual chemicals, and then dried at 60℃ for 3h to obtain a BOPP protective film.

[0066] In this embodiment, the preparation method of the hydrophilic antistatic pre-polymerization solution is as follows: dopamine is dissolved in deionized water, then dextran-phenylboronic acid solution is added, and then tris-hydroxymethyl aminomethane is added to adjust the pH value to 9. The concentration of dopamine in the hydrophilic antistatic pre-polymerization solution is 0.04g / L, and the mass ratio of dextran-phenylboronic acid to dopamine is 0.8:1.

[0067] In this embodiment, the antistatic agent is prepared by the following steps:

[0068] (1) 0.09 mol of antimony acetate and 1 mol of tin chloride were added to 150 mL of ethanol, then 1.2 mol of ethyl acetoacetate was slowly added dropwise, and stirred until clear to obtain a precursor solution;

[0069] (2) Slowly add the precursor solution to the titanium dioxide whisker suspension, heat to 100°C, stir the reaction until the solvent is completely evaporated, then calcine at 600°C for 3h, grind, and sieve through a 200 mesh screen to obtain the conductive whisker; the mass ratio of titanium dioxide whisker to tin chloride is 1.5:4; the titanium dioxide whisker suspension is obtained by ultrasonic dispersion of titanium dioxide whisker in deionized water at 65°C, and the concentration of titanium dioxide whisker in the titanium dioxide whisker suspension is 1g / L.

[0070] (3) Ultrasonically disperse 1.5g of conductive whisker in 500mL of anhydrous ethanol, then react with the amino silane hydrolysis solution to obtain a uniformly dispersed antistatic agent. The preparation method of the amino silane hydrolysis solution is as follows: γ-aminopropyl triethoxysilane (γ-aminopropyl triethoxysilane is 6wt% of the mass of the conductive whisker) is added to 30mL of an ethanol aqueous solution (the volume ratio of ethanol to water in the ethanol aqueous solution is 3:1), mixed uniformly, the pH of the solution is adjusted to 5 with 0.1mol / L dilute hydrochloric acid, and stirring is continued until the solution is transparent.

[0071] In this embodiment, the diameter of the titanium dioxide whisker is less than 40nm.

[0072] Control group 1

[0073] The same as example 1, except that the BOPP protective film is not treated by S4 and S5 steps, but is directly prepared by S1 and S2 and S3 steps.

[0074] Control group 2

[0075] The same as example 1, except that the preparation method of the antistatic agent does not go through step (3), but is directly prepared by steps (1) and (2).

[0076] Control group 3

[0077] The same as example 1, except that the preparation method of the hydrophilic antistatic prepolymer solution does not add dextran-benzene boronic acid.

[0078] Since the BOPP protective film prepared in control group 3 is dark brown, it is not suitable for electronic products, and therefore is not used for subsequent performance testing.

[0079] Performance test

[0080] (1) The performance of the BOPP protective film prepared in example 1 to example 3 and control group 1 to control group 2 is tested according to the GB / T1003-2008 test standard, and the results are shown in table 1.

[0081] Table 1. Performance test results

[0082]

[0083] As can be seen from Table 1, the BOPP protective films prepared in Examples 1-3 of this application have excellent physical and mechanical properties.

[0084] (2) The surface resistivity of the BOPP protective films prepared in Examples 1-3 and Control Groups 1-2 was measured using a weighted surface resistivity tester. The antistatic properties of the BOPP protective films were characterized by the surface resistivity (Ω). The results are as follows: Figure 1 As shown.

[0085] from Figure 1 As can be seen from the data, the BOPP protective films prepared in Examples 1-3 of this application have low surface resistivity, with a resistivity of 10... 7 -10 8 Between Ω.

[0086] (2) The microstructure of the BOPP protective film prepared in Example 1 was observed using a scanning electron microscope, such as... Figure 2 As shown.

[0087] from Figure 2 As can be seen, the antistatic agent is well dispersed in the polypropylene matrix, with no obvious agglomeration, and there are no obvious gaps between the antistatic agent and the polypropylene matrix, indicating good interfacial compatibility. The antistatic agent overlaps with each other in the polypropylene matrix.

[0088] (4) The surface of the BOPP protective film prepared in Example 1 was rubbed repeatedly with cotton cloth under a pressure of 5N 500 times (frequency 50 times / min), and the change in surface resistivity was tested. The results are as follows. Figure 3 As shown.

[0089] from Figure 3 As can be seen, after 500 cycles of rubbing, the surface resistivity of the BOPP protective film is no greater than 5 × 10⁻⁶. 9 Ω indicates that the BOPP protective film prepared in Example 1 of this application has long-lasting antistatic properties.

[0090] Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this invention.

Claims

1. A BOPP protective film, characterized in that: Preparation by the following steps: S1, polypropylene, slip agent mixing extrusion as core layer material; S2, polypropylene, maleic anhydride grafted polypropylene, antistatic agent mixing extrusion as surface layer material; S3, melt the core layer material in the main extruder, melt the surface layer material in two auxiliary extruders, extrude through the die, then biaxially stretch, to obtain BOPP film; S4, the BOPP film is subjected to corona treatment to obtain BOPP corona film; S5, the BOPP corona film is immersed in a hydrophilic antistatic prepolymerization solution to make the surface of the BOPP corona film have a hydrophilic antistatic layer, to obtain a BOPP protective film; the antistatic agent in S2 is 1-3% of the mass of polypropylene, and the addition amount of the maleic anhydride grafted polypropylene is 0.5-1.2% of the mass of polypropylene; the antistatic agent is prepared by the following steps: (1) adding antimony acetate and tin chloride into ethanol, then slowly adding ethyl acetoacetate, stirring until clear, to obtain a precursor solution; (2) slowly adding the precursor solution into a titanium dioxide whisker suspension, heating and reacting until the solvent is completely evaporated, then calcining, grinding, sieving, to obtain conductive whiskers; (3) ultrasonic dispersion of the conductive whiskers into anhydrous ethanol, then reacting with an amino silane hydrolysate, to obtain uniformly dispersed antistatic agent; the preparation method of the hydrophilic antistatic prepolymerization solution is: dissolving dopamine in deionized water, then adding a dextran-phenylboronic acid solution, and adding tris(hydroxymethyl)aminomethane to adjust the pH value to 8-9; the concentration of dopamine in the hydrophilic antistatic prepolymerization solution is 0.02-0.04 g / L, and the mass ratio of dextran-phenylboronic acid to dopamine is (0.5-0.8):

1.

2. The BOPP protective film according to claim 1, characterized in that: The molar amount ratio of antimony acetate, tin chloride, and ethyl acetoacetate is (0.07-0.09):1:(1.1-1.2).

3. The BOPP protective film according to claim 1, characterized in that: The mass amount ratio of titanium dioxide whiskers to tin chloride is (1.3-1.5):4; the heating reaction temperature is 90-100℃, and the calcination temperature is 450-600℃.

4. The BOPP protective film according to claim 3, characterized in that: The preparation method of the amino silane hydrolysate is: adding an amino silane coupling agent into an ethanol aqueous solution, mixing uniformly, adjusting the solution to be weakly acidic with dilute hydrochloric acid, and stirring until the solution is transparent; the amino silane coupling agent is 2-6wt% of the mass of the conductive whiskers.

5. The BOPP protective film according to claim 4, characterized in that: The diameter of the titanium dioxide whiskers is less than 40nm.

6. The BOPP protective film according to claim 5, characterized in that: The amino silane coupling agent is one of γ-aminopropyltrimethoxysilane, γ-aminopropyltriisopropoxysilane, and γ-aminopropyltriethoxysilane.

7. The BOPP protective film according to claim 1, characterized in that: The power of the corona treatment is 1-2kW.

8. Use of the BOPP protective film according to any one of claims 1 to 7 on electronic products, characterized in that: Used for electronic component packaging, battery packaging, and electronic product outer packaging.

Images