Easily-cleaned PET white board erasable film as well as preparation method and application thereof

Abstract

The invention relates to the technical field of PET polyester, and discloses an easy-to-clean PET whiteboard erasable film as well as a preparation method and application thereof. The preparation method comprises the following steps: mixing polyethylene glycol terephthalate and modified silicone oil, adding the mixture into a twin-screw extruder, carrying out melt extrusion and granulation, and then carrying out compression molding on PET particles through a molding press to obtain the easy-to-clean PET whiteboard erasable film. The modified silicone oil contains hydrophobic polysiloxane and long-chain alkane, so that the water contact angle of the PET film material is remarkably improved, the adhesion between the surface of the film material and water-based ink is reduced, the ink is convenient to clean and erase, the toughness, wear resistance and scratch resistance of the PET film material are improved, and the service life of the PET film material is prolonged. The method has better practical application in the aspects of office whiteboards and the like.

Description

Technical Field

[0001] This invention relates to the field of PET polyester technology, specifically to an easy-to-clean erasable PET whiteboard film, its preparation method, and its application. Background Technology

[0002] Office whiteboards are widely used in teaching, meetings, and personal note-taking. They are mainly made of metal, plastic, and glass, among which polyethylene terephthalate (PET) whiteboards are easy to process, lightweight, and low-cost, making them widely used. However, PET whiteboards have poor wear and scratch resistance, are easily scratched, and have poor impact resistance and other mechanical properties, severely affecting their lifespan.

[0003] Silicone oil is a high-performance polysiloxane substance with strong hydrophobicity, good wear resistance, and high flexibility, and it has important applications in films, coatings, plastics, and fibers. Patent publication number CN117586716B discloses a self-adhesive protective film for colored crystal glass and its preparation method. It uses 1,6-hexanediol diacrylate and hydrogen-containing silicone oil as raw materials to obtain an organosilicon tackifying component, which can improve the adhesion performance of PET film. However, this patent does not improve the wear and scratch resistance, or the ease of ink cleaning of the PET film, which is detrimental to the practical application of PET in office whiteboards. Summary of the Invention

[0004] The purpose of this invention is to provide an easy-to-clean PET wipeable film for whiteboards, which solves the problem that PET wipeable films are not easy to clean.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows: a method for preparing an easy-to-clean erasable film for PET whiteboards:

[0006] (1) Dichloromethane, 4-(allyloxycarbonyl)benzoic acid, alkyl alcohol, N,N-dicyclohexylcarbodiimide, and 4-dimethylaminopyridine were added to a reaction flask. After stirring and reacting, the mixture was filtered, and the filtrate was distilled under reduced pressure. The product was separated by column chromatography and eluted with ethyl acetate and petroleum ether solution to obtain alkyl 4-(allyloxycarbonyl)benzoic acid. The reaction formula is:

[0007] .

[0008] (2) Add toluene, hydrogen-containing silicone oil, and alkyl 4-(allyloxycarbonyl)benzoate to the reaction flask, purge with nitrogen, add chloroplatinic acid-isopropanol solution dropwise, distill under reduced pressure after reaction, wash the product with petroleum ether, and dry to obtain modified silicone oil.

[0009] (3) Mix polyethylene terephthalate and modified silicone oil, add to a twin-screw extruder, melt extrude, granulate, and then mold the PET granules through a molding machine to obtain an easy-to-clean PET whiteboard wipeable film.

[0010] Preferably, in (1), the reaction temperature is 20-30℃ and the reaction time is 3-5h.

[0011] Preferably, in (1), the molar amounts of alkyl alcohol, N,N-dicyclohexylcarbodiimide and 4-dimethylaminopyridine are 120-140%, 100-140% and 16-22% of the molar amount of 4-(allyloxycarbonyl)benzoic acid, respectively.

[0012] Preferably, in (1), the alkyl alcohol has the structural formula OH-C. n H 2n+1 n is any integer between 10 and 18.

[0013] Preferably, in (2), the mass of alkyl 4-(allyloxycarbonyl)benzoate and chloroplatinic acid are 3-15% and 0.0004-0.0025% of the mass of the hydrogen-containing silicone oil, respectively.

[0014] Preferably, the reaction temperature in (2) is 80-90℃ and the reaction time is 4-7h.

[0015] Preferably, the mass of the modified silicone oil in (3) is 5-20% of the mass of polyethylene terephthalate.

[0016] Preferably, in (3), the temperature of each section of the twin-screw extruder is 210-275℃ and the screw speed is 100-150r / min.

[0017] Preferably, in (3), the pressure during compression molding is 10-15MPa and the temperature is 260-270℃.

[0018] Preferably, the easy-to-clean PET whiteboard erasable film is used in the erasable whiteboard, which is composed of the easy-to-clean PET whiteboard erasable film, EVA hot melt adhesive, PET intermediate layer, EVA hot melt adhesive, and easy-to-clean PET whiteboard erasable film in sequence.

[0019] The beneficial technical effects of this invention are as follows: Modified silicone oil is obtained by adding the alkenyl group of alkyl 4-(allyloxycarbonyl)benzoate to the Si-H bond of hydrogen-containing silicone oil. This modified silicone oil is then melt-blended with PET and molded to obtain an easy-to-clean erasable PET whiteboard film. The modified silicone oil contains hydrophobic polysiloxanes and long-chain alkanes, which significantly improves the water contact angle of the PET film material. This helps reduce the adhesion between the film material surface and water-based inks, facilitating the cleaning and erasing of inks, and providing better practical applications in office whiteboards and other similar applications.

[0020] The modified silicone oil of this invention contains a large number of benzoic acid ester groups, which improves its compatibility with PET polyethylene terephthalate. This can improve the impact strength of PET materials, reduce wear, and enhance the toughness, wear resistance, scratch resistance, and service life of PET film materials and office whiteboards. Detailed Implementation

[0021] The present invention will be further illustrated by specific embodiments below. However, those skilled in the art should know that the specific embodiments of the present invention do not limit the present invention in any way, and any equivalent substitutions made on the basis of the present invention fall within the protection scope of the present invention.

[0022] 4-(allyloxycarbonyl)benzoic acid was prepared according to the method described in the journal article *HETEROCYCLES*, Vol. 96, No. 3, 2018, pp. 483-489, "APRACTICAL SYNTHESIS OF THE CYCLIC BUTYLENE TEREPHTHALATE TRIMER". The structural formula is as follows: .

[0023] Example 1 (1) Add 70 mL of dichloromethane, 30 mmol of 4-(allyloxycarbonyl)benzoic acid, 36 mmol of 1-hexadecyl alcohol, 30 mmol of N,N-dicyclohexylcarbodiimide, and 6.6 mmol of 4-dimethylaminopyridine to a reaction flask. Stir the mixture at 25 °C for 5 h. After filtration, distill the filtrate under reduced pressure. Separate the product by column chromatography, eluting with ethyl acetate and petroleum ether solution to obtain alkyl 4-(allyloxycarbonyl)benzoic acid, with the following structural formula: .

[0024] (2) Add 100 mL of toluene, 80 g of hydrogen-containing silicone oil (model Guangzhou Huining Chemical TSF484, the same below) and 2.4 g of alkyl 4-(allyloxycarbonyl)benzoate to the reaction flask, purge with nitrogen gas, add 20 μL of isopropanol solution containing 0.32 mg chloroplatinic acid dropwise, heat to 80 °C, stir and react for 5 h, distill under reduced pressure, wash the product with petroleum ether, dry, and obtain modified silicone oil.

[0025] (3) Mix 1 kg of polyethylene terephthalate (model Dongguan Mingyuan Plastics PT X174, the same below) and 50 g of modified silicone oil, add them to a twin-screw extruder, melt extrude, the temperature of each section is 210℃, 240℃, 260℃, 270℃, 275℃, 270℃, the screw speed is 100 r / min, granulate, and then the PET granules are molded by a molding machine with a pressure of 10 MPa and a temperature of 270℃, and cooled to obtain an easy-to-clean PET whiteboard erasable film, which can be applied to erasable whiteboards.

[0026] Example 2 (1) Add 80 mL of dichloromethane, 30 mmol of 4-(allyloxycarbonyl)benzoic acid, 42 mmol of 1-octadecyl alcohol, 42 mmol of N,N-dicyclohexylcarbodiimide and 4.8 mmol of 4-dimethylaminopyridine to the reaction flask, stir at 30 °C for 3 h, filter, distill under reduced pressure, separate the product by column chromatography, elute with ethyl acetate and petroleum ether solution to obtain alkyl 4-(allyloxycarbonyl)benzoic acid.

[0027] (2) Add 150 mL of toluene, 80 g of hydrogen-containing silicone oil and 7 g of alkyl 4-(allyloxycarbonyl)benzoate to the reaction flask, purge with nitrogen, add 60 μL of isopropanol solution containing 1.2 mg of chloroplatinic acid dropwise, heat to 90 °C, stir and react for 4 h, distill under reduced pressure, wash the product with petroleum ether, dry, and obtain modified silicone oil.

[0028] (3) Mix 1 kg of polyethylene terephthalate and 120 g of modified silicone oil, add them to a twin-screw extruder, melt extrude, and set the temperatures of each section to 210℃, 240℃, 260℃, 270℃, 275℃, and 270℃, with a screw speed of 100 r / min. Granulate the PET granules and then mold them through a molding press at a pressure of 15 MPa and a temperature of 260℃. Cool the granules to obtain an easy-to-clean PET whiteboard erasable film, which can be used in erasable whiteboards.

[0029] Example 3 (1) Add 80 mL of dichloromethane, 30 mmol of 4-(allyloxycarbonyl)benzoic acid, 40 mmol of 1-decyl alcohol, 30 mmol of N,N-dicyclohexylcarbodiimide, and 5.6 mmol of 4-dimethylaminopyridine to the reaction flask. Stir the reaction at 20 °C for 5 h. After filtration, the filtrate is distilled under reduced pressure. The product is separated by column chromatography and eluted with ethyl acetate and petroleum ether solution to obtain alkyl 4-(allyloxycarbonyl)benzoic acid.

[0030] (2) Add 150 mL of toluene, 80 g of hydrogen-containing silicone oil and 12 g of alkyl 4-(allyloxycarbonyl)benzoate to the reaction flask, purge with nitrogen, add 100 μL of isopropanol solution containing 2 mg of chloroplatinic acid dropwise, heat to 80 °C, stir and react for 7 h, distill under reduced pressure, wash the product with petroleum ether, dry, and obtain modified silicone oil.

[0031] (3) Mix 1 kg of polyethylene terephthalate and 200 g of modified silicone oil, add them to a twin-screw extruder, melt extrude, and set the temperatures of each section to 210℃, 240℃, 260℃, 270℃, 275℃, and 270℃, with a screw speed of 150 r / min. Granulate the PET granules and then mold them through a molding press at a pressure of 15 MPa and a temperature of 270℃. Cool the granules to obtain an easy-to-clean PET whiteboard erasable film, which can be used in erasable whiteboards.

[0032] Comparative Example 1 (1) Add 1 kg of polyethylene terephthalate to a twin-screw extruder and melt extrude it. The temperatures of each section are 210℃, 240℃, 260℃, 270℃, 275℃ and 270℃, and the screw speed is 100 r / min. Granulate the PET granules and then mold them through a molding press at a pressure of 10 MPa and a temperature of 270℃. Cool the PET whiteboard wipeable film.

[0033] Comparative Example 2 (1) Mix 1 kg of polyethylene terephthalate and 50 g of hydrogen-containing silicone oil, add them to a twin-screw extruder, melt extrude, the temperature of each section is 210℃, 240℃, 260℃, 270℃, 275℃, 270℃, the screw speed is 100 r / min, granulate, and then the PET granules are molded by a molding press at a pressure of 10 MPa and a temperature of 270℃, and cooled to obtain a PET white board wipeable film.

[0034] Comparative Example 3 (1) Add 100 mL of toluene, 80 g of hydrogen-containing silicone oil, and 2.4 g of allyl benzoate (structural formula: (CAS Registry No. 583-04-0), nitrogen gas was introduced, and 20 μL of isopropanol solution containing 0.32 mg chloroplatinic acid was added dropwise. The mixture was heated to 80 °C, stirred for 5 h, distilled under reduced pressure, washed with petroleum ether, and dried to obtain modified silicone oil.

[0035] (2) Mix 1 kg of polyethylene terephthalate and 50 g of modified silicone oil, add them to a twin-screw extruder, melt extrude, and set the temperatures of each section to 210℃, 240℃, 260℃, 270℃, 275℃ and 270℃, and the screw speed to 100 r / min. Granulate the PET granules and then mold them through a molding press at a pressure of 10 MPa and a temperature of 270℃. Cool the PET granules to obtain a PET whiteboard wipeable film.

[0036] Comparative Example 4 (1) Add 70 mL of dichloromethane, 30 mmol of 4-(allyloxycarbonyl)benzoic acid, 36 mmol of ethanol, 30 mmol of N,N-dicyclohexylcarbodiimide, and 6.6 mmol of 4-dimethylaminopyridine to a reaction flask. Stir the mixture at 25 °C for 5 h. After filtration, distill the filtrate under reduced pressure. Separate the product by column chromatography, eluting with ethyl acetate and petroleum ether solution to obtain ethyl 4-(allyloxycarbonyl)benzoate, with the structural formula: .

[0037] (2) Add 100 mL of toluene, 80 g of hydrogen-containing silicone oil and 2.4 g of ethyl 4-(allyloxycarbonyl)benzoate to the reaction flask, purge with nitrogen gas, add 20 μL of isopropanol solution containing 0.32 mg of chloroplatinic acid dropwise, heat to 80 °C, stir and react for 5 h, distill under reduced pressure, wash the product with petroleum ether, dry, and obtain modified silicone oil.

[0038] (3) Mix 1 kg of polyethylene terephthalate and 50 g of modified silicone oil, add them to a twin-screw extruder, melt extrude, and set the temperatures of each section to 210℃, 240℃, 260℃, 270℃, 275℃ and 270℃, and the screw speed to 100 r / min. Granulate the PET granules and then mold them through a molding press at a pressure of 10 MPa and a temperature of 270℃. Cool the PET whiteboard wipeable film.

[0039] The surface contact angle of the erasable film on PET whiteboard is tested according to standard GB / T 30693-2014.

[0040] Impact strength testing was conducted by injection molding the PET granules prepared in each example and comparative example using an injection molding machine at temperatures of 260℃, 275℃, and 275℃. PET test strips were then made, and their impact strength was tested according to standard GB / T1843-2008. The abrasion resistance of the test strips was tested according to standard GB / T 3960-2016.

[0041] Table 1 Performance of PET film

[0042] The PET film material in Comparative Example 1 has a low water contact angle, which is not conducive to reducing the adhesion between the film material surface and water-based inks, making it difficult to clean and wipe off the ink. In addition, the impact strength is low, the mechanical properties of the PET film are poor, the wear is large, and the wear and scratch resistance is poor.

[0043] Modified silicone oil was added to the PET film materials of Examples 1-3. This modified silicone oil contains hydrophobic polysiloxanes and long-chain alkanes, which significantly improves the water contact angle of the PET film material. This helps reduce the adhesion between the film material surface and water-based inks, facilitating ink cleaning and removal. Furthermore, the modified silicone oil contains a large number of benzoate groups (…). The improved compatibility with PET (polyethylene terephthalate) can enhance the impact strength of PET materials, reduce wear, and improve toughness, abrasion resistance, scratch resistance, and service life.

[0044] Compared with Example 1, the hydrogen-containing silicone oil added in Comparative Example 2 does not contain hydrophobic long-chain alkanes, the water contact angle of PET is lower, and the compatibility between the hydrogen-containing silicone oil and PET is poor, which is not conducive to improving the toughness and abrasion resistance of PET.

[0045] The allyl benzoate and the modified silicone oil prepared in Comparative Example 3 do not contain hydrophobic long-chain alkanes, have a low water contact angle with PET, and contain less benzoate groups. Their compatibility with PET is lower than that in Example 1, resulting in lower impact strength and greater wear.

[0046] The ethyl 4-(allyloxycarbonyl)benzoate of Comparative Example 4 and the modified silicone oil prepared therefrom do not contain hydrophobic long-chain alkanes, resulting in a lower water contact angle for PET.

[0047] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A method for preparing an easy-to-clean erasable film for PET whiteboards, characterized in that, The preparation method includes: (1) Add toluene, hydrogen-containing silicone oil, and alkyl 4-(allyloxycarbonyl)benzoate to the reaction flask, purge with nitrogen, add chloroplatinic acid-isopropanol solution dropwise, distill under reduced pressure after reaction, wash the product, dry, and obtain modified silicone oil. (2) Mix polyethylene terephthalate and modified silicone oil, add to a twin-screw extruder, melt extrude, granulate, and then mold the PET granules through a molding press to obtain an easy-to-clean PET whiteboard wipeable film.

2. The easy-to-clean erasable PET whiteboard film and its preparation method according to claim 1, characterized in that, In (1), the mass of alkyl 4-(allyloxycarbonyl)benzoate and chloroplatinic acid are 3-15% and 0.0004-0.0025% of the mass of the hydrogen-containing silicone oil, respectively.

3. The method for preparing the easy-to-clean erasable film for PET whiteboards according to claim 1, characterized in that, The reaction temperature in (1) is 80-90℃ and the reaction time is 4-7h.

4. The method for preparing the easy-to-clean erasable film for PET whiteboards according to claim 1, characterized in that, The mass of the modified silicone oil in (2) is 5-20% of the mass of polyethylene terephthalate.

5. The method for preparing the easy-to-clean erasable film for PET whiteboards according to claim 1, characterized in that, The temperature of each section of the twin-screw extruder in (2) is 210-275℃, and the screw speed is 100-150r / min.

6. The method for preparing the easy-to-clean erasable film for PET whiteboards according to claim 1, characterized in that, The pressure during compression molding in (2) is 10-15 MPa and the temperature is 260-270℃.

7. The method for preparing the easy-to-clean erasable film for PET whiteboards according to claim 1, characterized in that, The preparation method of the alkyl 4-(allyloxycarbonyl)benzoate includes: adding dichloromethane, 4-(allyloxycarbonyl)benzoic acid, alkyl alcohol, N,N-dicyclohexylcarbodiimide, and 4-dimethylaminopyridine to a reaction flask, stirring the reaction at 20-30℃ for 3-5 h, filtering the filtrate and distilling it under reduced pressure, and separating the product by column chromatography to obtain the alkyl 4-(allyloxycarbonyl)benzoate.

8. The method for preparing the easy-to-clean erasable film for PET whiteboards according to claim 7, characterized in that, The molar amounts of the alkyl alcohol, N,N-dicyclohexylcarbodiimide, and 4-dimethylaminopyridine are 120-140%, 100-140%, and 16-22% of the molar amount of 4-(allyloxycarbonyl)benzoic acid, respectively; the structural formula of the alkyl alcohol is OH-C. n H 2n+1 n is any integer between 10 and 18.

9. An easy-to-clean erasable PET whiteboard film obtained by the preparation method according to any one of claims 1-8.

10. The application of the easy-to-clean PET whiteboard erasable film as described in claim 9 in erasable whiteboards, characterized in that, The erasable whiteboard is composed of an easy-to-clean PET whiteboard erasable film, EVA hot melt adhesive, PET intermediate layer, EVA hot melt adhesive, and easy-to-clean PET whiteboard erasable film.

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