A BOPET film for gilding transfer and a preparation method thereof

Abstract

The application discloses a BOPET film for gold stamping transfer and a preparation method thereof, and belongs to the technical field of BOPET films. The BOPET film for gold stamping transfer comprises, from top to bottom, an upper surface layer, a core layer and a lower surface layer. The upper surface layer and the lower surface layer are made of the same raw material and both comprise bright polyester chips with a mass ratio of (2-4):(6-8) and irregular SiO2 modified anti-adhesion masterbatch with different particle sizes. The raw material of the core layer is graphene modified polyester chips. The BOPET film has the advantages of low resistivity, high surface roughness, low friction coefficient, large wetting tension and excellent mechanical properties, and can ensure that the color layer of the gold stamping film is firm and does not fall off, and can be completely transferred during thermal transfer, thereby meeting the requirements of high-speed production.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of BOPET film, and particularly relates to a BOPET film for gold stamping transfer and a preparation method thereof. BACKGROUND

[0002] The gold stamping film, also known as an electrochemical aluminum, is a kind of composite stamping material composed of a base film support layer, a release layer (peeling layer), a protective layer, a dyeing layer, an aluminum plating layer and an adhesive layer, and is widely applied to the paper card, plastic, cosmetics, textile, electrical and digital industries. The base material layer is usually a plastic film such as PVC, OPP and BOPET, which supports the above layers, and the BOPET is often used as a carrier of the stamping material in actual production due to its advantages such as high temperature resistance (melting point > 255 DEG C), easy degradation (environmental protection material), two-way stretchability (high strength and low breakage rate).

[0003] The process of gold stamping transfer is to heat and press the metal color layer on the printing material through a bottom plate containing specific information at a certain temperature and pressure, so as to form a specific pattern. However, in the process of heat transfer, the metal color layer often falls off and is not transferred well (peeling is not complete), which presents serious appearance defects such as dots, irregularities and mottling in the printing material, and affects the visual appearance of the final product.

[0004] The reason for the problem is that the manufacturers constantly improve the equipment running speed in order to pursue higher economic benefits, so that the film and the transmission roller are frequently rubbed, a large amount of heterogeneous charges are accumulated, a disorderly electric field distribution is formed on the surface, and a strong adsorption or repulsion effect is generated on different charged particles in the external environment. If the film surface adsorbs small impurity particles in the air, the color layer after multiple coating and drying will fall off due to insufficient adhesion. Secondly, the adhesion of the commonly used organic silicon release agent (polydimethylsiloxane) to the PET polyester surface is limited at high speed coating, which is easy to cause coating leakage in production, so that the metal color layer directly contacts the base film, which cannot be effectively transferred to the printing material during heat transfer, resulting in the phenomenon of poor transfer and peeling residue of the base film. Therefore, in order to solve the above problems existing in the process of heat transfer, it is urgent to research a kind of BOPET film with excellent performance and suitable for gold stamping transfer. SUMMARY

[0005] In view of the deficiencies of the prior art, the purpose of the present application is to provide a BOPET film for gold stamping transfer and a preparation method thereof, which solves the problems in the prior art.

[0006] The purpose of the present application can be realized by the following technical solutions:

[0007] A BOPET film for gold stamping transfer comprises, from top to bottom, an upper surface layer, a core layer and a lower surface layer.

[0008] The raw materials of the upper and lower surface layers are the same, and each comprises: light polyester chips with a mass ratio of (2-4):(6-8) and irregular SiO2 modified anti-adhesion masterbatch with different particle sizes;

[0009] The raw material of the core layer is graphene modified polyester chips.

[0010] Further, the graphene modified polyester chips are made by melt blending nano-graphene particles and polyethylene terephthalate.

[0011] Further, the irregular SiO2 modified anti-adhesion masterbatch with different particle sizes is made by pre-mixing irregular SiO2 particles with different particle sizes, then stirring with terephthalic acid, isophthalic acid and ethylene glycol, and then esterification and polycondensation.

[0012] Further, the particle content of the irregular SiO2 modified anti-adhesion masterbatch with different particle sizes is 3300 ppm.

[0013] Further, the particle size range of the irregular SiO2 particles is 1.5-5.0 um.

[0014] Further, the particle size range of the nano-graphene particles is 5-20 nm.

[0015] Further, the thickness of the upper and lower surface layers is 1.1 um, and the thickness of the core layer is 9.8 um.

[0016] The preparation method of the above-mentioned BOPET film for gilding transfer comprises the following steps:

[0017] S1, after the core layer raw material is pre-crystallized, dried and impurity-removed, it is sent into a single screw extruder for melt extrusion, filtration to obtain a core layer melt; and the upper and lower surface layer raw materials are respectively sent into a double screw extruder for melt extrusion, vacuum drying and filtration to obtain an upper surface layer melt and a lower surface layer melt;

[0018] S2, the core layer melt, the upper surface layer melt and the lower surface layer melt are converged at a die head, cast and attached to the surface of a low-temperature cold roller under the action of high-voltage static electricity to form a polyester thick sheet with a three-layer structure;

[0019] S3, the polyester thick sheet is passed to a longitudinal stretching section, preheated and then longitudinally stretched, and then enters a transverse stretching section for preheating, transverse stretching, heat setting and cooling treatment to form a biaxially stretched polyester film;

[0020] S4, the biaxially stretched polyester film enters a traction stage for flattening, thickness measurement and edge trimming, and is wound into a master roll, and finally cut into finished film.

[0021] Further, in S3: the preheating temperature of longitudinal stretching is 90 DEG C, the stretching temperature is 110 DEG C, and the stretching ratio is 3.7; the preheating temperature of transverse stretching is 100 DEG C, the stretching temperature is 115 DEG C, the heat setting temperature is 230 DEG C, and the stretching ratio is 3.6; and the cooling temperature is 25 DEG C.

[0022] The application of the above-mentioned BOPET film for gilding transfer as a gilding carrier in gilding transfer.

[0023] The beneficial effects of the present application are:

[0024] 1. The PET chip in the film core layer is blended and modified by adding graphene particles, which can significantly reduce the film resistivity, shorten the charge decay half-life, and make the film timely leak the static electricity accumulated by friction; the surface layer of the film is an anti-sticking masterbatch made by copolymerization of ordinary chips and SiO2 with different particle sizes and irregular morphology, and the anti-sticking particles in the masterbatch have large particle size difference and random irregular morphology, so the surface roughness of the formed film is obviously improved compared with ordinary films, the air between the wound film layers is filled more, the friction coefficient between the films is reduced, and the film smoothness is enhanced, thereby reducing the generation of static electricity.

[0025] 2. Due to the improved surface roughness, the contact angle of the film surface is also reduced, so that the film under the corona discharge has higher wetting tension, which helps the specific gravity and uniformity of the downstream coated silicone release agent, and avoids missed coating points.

[0026] 3. SiO2 itself acts as a heterogeneous nucleating agent to enhance and toughen the polymer, and irregular particles with different particle sizes are more likely to hinder chain segment movement, increase the friction force between molecular chains, and increase the viscosity of the material, thereby improving the rigidity and mechanical properties of the film, and better adapting to high-speed production.

[0027] 4. The BOPET film prepared by the present application has the advantages of low resistivity, high surface roughness, low friction coefficient, high wetting tension, and excellent mechanical properties, which not only ensures the firmness and non-falling of the gilding film color layer, but also enables it to be completely transferred during thermal transfer, meeting the requirements of high-speed production. DETAILED DESCRIPTION

[0028] The technical solutions of the present application will be described clearly and completely in combination with the embodiments in the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor belong to the scope of protection of the present application.

[0029] The technical solutions of the present application are illustrated below by the following examples and comparative examples, wherein the BOPET film prepared for gilding transfer in the examples and comparative examples is a three-layer structure, from top to bottom, including an upper surface layer, a core layer, and a lower surface layer, wherein the thickness of the upper surface layer and the lower surface layer is 1.1 um, the thickness of the core layer is 9.8 um, and the total thickness of the BOPET film is 12 um;

[0030] All raw materials for preparing the BOPET film for gilding transfer include:

[0031] Bright polyester chip, graphene modified polyester chip A (5 nm, 2.5%), graphene modified polyester chip B (10 nm, 1.2%), graphene modified polyester chip C (20 nm, 0.5%), irregular SiO2 modified anti-adhesion masterbatch of different particle sizes (specific particle size and doping ratio see specific examples and comparative examples), and commercial silicon type anti-adhesion masterbatch (3.5 μm / 3300 ppm);

[0032] Among them, the graphene modified polyester chip is made by melt blending nano graphene particles with polyethylene terephthalate, and the specific preparation process is as follows: nano graphene powder (5, 10, 20 nm) of different particle sizes is vacuum dried at 150°C, and ordinary PET chip is air-dried at 115°C for 12 hours, and then vacuum dried at 165°C for 12 hours for standby; Then, according to the mass fraction of the corresponding particle size, mix with the PET chip, and then fully stir uniformly with a high-speed disperser, to obtain three kinds of mixed masterbatch with particle size of 5 nm, mass fraction of 2.5%, particle size of 10 nm, mass fraction of 1.2%, and particle size of 20 nm, mass fraction of 0.5%, respectively. Finally, the masterbatch is melted, extruded and granulated at 275°C to obtain nano graphene modified masterbatch A, B and C.

[0033] The irregular SiO2 modified anti-adhesion masterbatch of different particle sizes is prepared by pre-mixing irregular SiO2 particles of different particle sizes, then stirring with terephthalic acid, isophthalic acid and ethylene glycol, and then esterification and polycondensation.

[0034] Example 1

[0035] A method for preparing a BOPET film for gilding transfer, comprising the following steps:

[0036] S1, configuring upper surface layer, core layer, and lower surface layer raw materials;

[0037] The upper surface layer raw material includes 30% by mass of bright polyester chip and 70% by mass of irregular SiO2 modified anti-adhesion masterbatch of different particle sizes;

[0038] The raw material of the core layer is graphene modified polyester chip A;

[0039] The lower surface layer raw material includes 30% by mass of bright polyester chips and 70% by mass of irregular SiO2 modified anti-adhesion masterbatch with different particle sizes.

[0040] In this embodiment, the preparation process of the irregular SiO2 modified anti-adhesion masterbatch with different particle sizes includes:

[0041] 1) The irregular SiO2 particles with a particle size of 1.5 μm and the irregular SiO2 particles with a particle size of 2.5 μm are premixed at a molar ratio of 1:1 to obtain a particle mixture;

[0042] 2) The particle mixture is added to a reaction kettle containing terephthalic acid, isophthalic acid and ethylene glycol and stirred thoroughly; the molar ratio of terephthalic acid to isophthalic acid is 9:1, the molar ratio of ethylene glycol to the total amount of diacid is 1.25:1, and the mass fraction of the particle mixture is 0.33%; then esterification and dehydration are carried out under the conditions of a temperature of 250°C, a pressure of 0.25 MPa and a stirring frequency of 25 Hz, the pressure is gradually reduced and the temperature is gradually increased for pre-polycondensation after the water output reaches more than 95%, and finally the polycondensation reaction is carried out by adjusting the pressure in the kettle to 70 Pa and the temperature to 280°C, followed by drawing, cooling and granulation to obtain the irregular SiO2 modified anti-adhesion masterbatch with different particle sizes, and the particle content of the masterbatch is 3300 ppm.

[0043] The preparation process of the graphene modified polyester chip A includes:

[0044] The graphene powder with a particle size of 5 nm is vacuum dried at 150°C, and the ordinary PET chip is first air-dried at 115°C for 12 h and then vacuum dried at 165°C for 12 h for standby; then the powder and the PET chip are mixed and fully mixed and dispersed by a high-speed stirrer to obtain a mixed masterbatch with a particle size of 5 nm and a mass fraction of 2.5%, and finally the masterbatch is melted, extruded and granulated at 275°C to obtain the nano-graphene modified masterbatch A.

[0045] S2, after the core layer raw material is uniformly mixed and pre-crystallized at 160°C, it is sent into a fluidized bed, and then air-dried and impurity-removed in a drying tower, and then melted and extruded into a filter screen at 280°C in a single-screw extruder, and finally metered by a melt pump and conveyed to a die head;

[0046] The upper surface layer raw material is uniformly mixed and directly sent into a double-screw extruder, melted and extruded at 280°C, and the melt is vacuum dried to remove water and impurities, and then conveyed to a die head through a filter screen and a melt pump;

[0047] The underlayer raw material is mixed uniformly and then directly fed into a twin-screw extruder, melted and extruded at 280°C, and at the same time, the melt is vacuum dried to remove water and impurities, and then conveyed to the die through a filter screen and a melt pump;

[0048] The melts of the core layer, the upper and lower surface layers are combined at the die to form a melt with a three-layer structure; then, the melt slowly flows out of the die lip and closely adheres to the surface of a cold roller at 27°C under the action of a high-voltage static electric field, forming a polyester thick sheet with a three-layer structure.

[0049] S3, the polyester thick sheet is fed to a longitudinal stretching section, and longitudinal stretching is completed under the conditions of a preheating temperature of 90°C, a stretching temperature of 110°C, and a stretching ratio of 3.7, and then the polyester thick sheet is fed to a transverse stretching section, and transverse stretching is completed under the conditions of a preheating temperature of 100°C, a stretching temperature of 115°C, a setting temperature of 230°C, and a stretching ratio of 3.6, and the biaxially stretched polyester film is obtained by cooling at 25°C.

[0050] S4, the biaxially stretched polyester film is fed to a traction stage to be flattened, measured in thickness, and trimmed, and then wound into a mother roll, and finally, the finished film is obtained by slitting.

[0051] Example 2

[0052] The difference between this example and Example 1 is only that the particle size of the irregular SiO2 is changed in the raw material formula; the specific steps are as follows:

[0053] S1, the upper surface layer, the core layer, and the lower surface layer raw materials are configured;

[0054] The upper surface layer raw material includes 30% by mass fraction of large-gloss polyester chips and 70% by mass fraction of irregular SiO2 modified anti-adhesion masterbatch with different particle sizes;

[0055] The raw material of the core layer is graphene modified polyester chips A;

[0056] The lower surface layer raw material includes 30% by mass fraction of large-gloss polyester chips and 70% by mass fraction of irregular SiO2 modified anti-adhesion masterbatch with different particle sizes.

[0057] In this example, the preparation process of the irregular SiO2 modified anti-adhesion masterbatch with different particle sizes includes:

[0058] 1) irregular SiO2 particles with a particle size of 1.5 μm and irregular SiO2 particles with a particle size of 3.5 μm are pre-mixed at a molar ratio of 1:1 to obtain a particle mixture;

[0059] 2) The particle mixture is added to a reaction kettle containing terephthalic acid, isophthalic acid and ethylene glycol, and stirred thoroughly; the molar ratio of terephthalic acid to isophthalic acid is 9:1, the molar ratio of ethylene glycol to total diacid is 1.25:1, and the mass fraction of the particle mixture is 0.33%; then esterification and dehydration are carried out at a temperature of 250°C, a pressure of 0.25 MPa, and a stirring frequency of 25 Hz, and after the water output reaches more than 95%, the pressure is gradually reduced and the temperature is gradually increased to cause pre-polycondensation, and finally the pressure in the kettle is adjusted to 70 Pa and the temperature is adjusted to 280°C to carry out polycondensation, after which drawing, cooling and pelletizing are carried out to obtain irregular SiO2 modified anti-adhesion masterbatch with different particle sizes, and the particle content of the masterbatch is 3300 ppm.

[0060] The preparation process of the graphene modified polyester chip A is the same as S1.

[0061] S2-S4 are the same as Example 1.

[0062] Example 3

[0063] The difference between this example and Example 1 is only that the particle size of the irregular SiO2 is changed in the raw material formula; the specific steps are as follows:

[0064] S1, configure the upper surface layer, core layer, and lower surface layer raw materials;

[0065] The upper surface layer raw materials include 30% by mass fraction of bright polyester chips and 70% by mass fraction of irregular SiO2 modified anti-adhesion masterbatch with different particle sizes;

[0066] The raw material of the core layer is graphene modified polyester chip A;

[0067] The lower surface layer raw materials include 30% by mass fraction of bright polyester chips and 70% by mass fraction of irregular SiO2 modified anti-adhesion masterbatch with different particle sizes.

[0068] In this example, the preparation process of the irregular SiO2 modified anti-adhesion masterbatch with different particle sizes includes:

[0069] 1) The irregular SiO2 particles with a particle size of 1.5 μm and the irregular SiO2 particles with a particle size of 5.0 μm are pre-mixed at a molar ratio of 1:1 to obtain a particle mixture;

[0070] 2) The particle mixture is added to a reaction kettle containing terephthalic acid, isophthalic acid and ethylene glycol with sufficient stirring; wherein the molar ratio of terephthalic acid to isophthalic acid is 9:1, the molar ratio of ethylene glycol to the total diacid is 1.25:1, and the mass fraction of the particle mixture is 0.33%; then esterification and dehydration are carried out at a temperature of 250°C, a pressure of 0.25 MPa, and a stirring frequency of 25 Hz, and after the water output reaches more than 95%, the pressure is gradually reduced and the temperature is gradually increased to cause pre-polycondensation, and finally the pressure in the kettle is adjusted to 70 Pa and the temperature is adjusted to 280°C for polycondensation reaction, after which drawing, cooling and pelletizing are carried out to obtain irregular SiO2 modified anti-adhesion masterbatch with different particle sizes, and the particle content of the masterbatch is 3300 ppm.

[0071] The preparation process of the graphene modified polyester chip A is the same as S1.

[0072] S2-S4 are the same as Example 1.

[0073] Example 4

[0074] The difference between this example and Example 1 is only that the type of graphene modified polyester chip in the core layer is changed in the raw material formula; the specific is as follows:

[0075] S1, configure the upper surface layer, core layer, and lower surface layer raw materials;

[0076] The upper surface layer raw material includes 30% by mass fraction of bright polyester chip and 70% by mass fraction of irregular SiO2 modified anti-adhesion masterbatch with different particle sizes;

[0077] The raw material of the core layer is graphene modified polyester chip B;

[0078] The lower surface layer raw material includes 30% by mass fraction of bright polyester chip and 70% by mass fraction of irregular SiO2 modified anti-adhesion masterbatch with different particle sizes.

[0079] The preparation process of the graphene modified polyester chip B includes:

[0080] The preparation process of the graphene modified polyester chip B includes:

[0081] The graphene powder with a particle size of 10 nm is vacuum dried at 150°C, and the ordinary PET chip is first air-dried at 115°C for 12 hours, and then vacuum dried at 165°C for 12 hours for standby; then the powder and the PET chip are mixed and fully mixed and dispersed by a high-speed stirrer to obtain a mixed masterbatch with a particle size of 5 nm and a mass fraction of 1.2%, and finally the masterbatch is melted, extruded and pelletized at 275°C to obtain nano-graphene modified masterbatch B.

[0082] S2-S4 are the same as example 1.

[0083] Example 5

[0084] The difference between this example and example 1 is only that the type of graphene modified polyester chip in the core layer is changed in the raw material formula; the specific steps are as follows:

[0085] S1, configure the upper surface layer, core layer, and lower surface layer raw materials;

[0086] The upper surface layer raw material includes 30% by mass fraction of bright polyester chip and 70% by mass fraction of irregular SiO2 modified anti-adhesion masterbatch of different particle sizes;

[0087] The raw material of the core layer is graphene modified polyester chip C;

[0088] The lower surface layer raw material includes 30% by mass fraction of bright polyester chip and 70% by mass fraction of irregular SiO2 modified anti-adhesion masterbatch of different particle sizes.

[0089] The preparation process of the irregular SiO2 modified anti-adhesion masterbatch of different particle sizes is the same as that of example 1, which includes:

[0090] The preparation process of the graphene modified polyester chip C includes:

[0091] The graphene powder with a particle size of 20 nm is vacuum dried at 150°C, and the ordinary PET chip is first blown dry at 115°C for 12h, and then vacuum dried at 165°C for 12h for standby; then the powder and the PET chip are mixed and fully mixed and dispersed by a high-speed stirrer to obtain a mixed masterbatch with a particle size of 5 nm and a mass fraction of 0.5%, and finally the masterbatch is melted, extruded and granulated at 275°C to obtain the nanometer graphene modified masterbatch C.

[0092] S2-S4 are the same as example 1.

[0093] Example 6

[0094] The difference between this example and example 1 is only that the proportion of the raw materials in the upper and lower surface layers is changed; the specific steps are as follows:

[0095] S1, configure the upper surface layer, core layer, and lower surface layer raw materials;

[0096] The upper surface layer raw material includes 20% by mass fraction of bright polyester chip and 80% by mass fraction of irregular SiO2 modified anti-adhesion masterbatch of different particle sizes;

[0097] The raw material of the core layer is graphene modified polyester chip A;

[0098] The upper surface layer raw material includes: 20% by mass of bright polyester chip and 80% by mass of irregular SiO2 modified anti-adhesion masterbatch with different particle sizes.

[0099] In this embodiment, the preparation process of the irregular SiO2 modified anti-adhesion masterbatch with different particle sizes is the same as that in Example 1. The preparation process of the graphene modified polyester chip A is the same as that in Example 1.

[0100] S2-S4 are the same as in Example 1.

[0101] Example 7

[0102] This embodiment differs from Example 1 only in that the proportions of the raw materials in the upper and lower surface layers are changed. The specific steps are:

[0103] S1, configuring the upper surface layer, core layer, and lower surface layer raw materials;

[0104] The upper surface layer raw material includes: 40% by mass of bright polyester chip and 60% by mass of irregular SiO2 modified anti-adhesion masterbatch with different particle sizes;

[0105] The raw material of the core layer is: graphene modified polyester chip A;

[0106] The lower surface layer raw material includes: 40% by mass of bright polyester chip and 60% by mass of irregular SiO2 modified anti-adhesion masterbatch with different particle sizes.

[0107] In this embodiment, the preparation process of the irregular SiO2 modified anti-adhesion masterbatch with different particle sizes is the same as that in Example 1. The preparation process of the graphene modified polyester chip A is the same as that in Example 1.

[0108] S2-S4 are the same as in Example 1.

[0109] Comparative Example 1

[0110] Comparative Example 1 differs from Example 1 only in that the core layer raw material is changed to: bright polyester chip;

[0111] The specific steps are:

[0112] S1, configuring the upper surface layer, core layer, and lower surface layer raw materials;

[0113] The upper surface layer raw material includes: 30% by mass of bright polyester chip and 70% by mass of irregular SiO2 modified anti-adhesion masterbatch with different particle sizes;

[0114] The raw material of the core layer is: bright polyester chip;

[0115] The lower surface layer raw material includes: 30% by mass of bright polyester chip and 70% by mass of irregular SiO2 modified anti-adhesion masterbatch with different particle sizes.

[0116] In the embodiment, the preparation process of the irregular SiO2 modified anti-adhesion masterbatch with different particle sizes is the same as that in Embodiment 1.

[0117] S2-S4 are the same as those in Embodiment 1.

[0118] Comparative Example 2

[0119] Comparative Example 2 is different from Embodiment 1 only in that the irregular SiO2 modified anti-adhesion masterbatch with different particle sizes in the upper and lower surface layers is replaced by a commercial silicon type anti-adhesion masterbatch. The specific steps are as follows:

[0120] S1, configuring the upper surface layer, core layer, and lower surface layer raw materials;

[0121] The upper surface layer raw materials include 30% by mass fraction of large-gloss polyester chips and 70% by mass fraction of a commercial silicon type anti-adhesion masterbatch.

[0122] The raw material of the core layer is graphene modified polyester chips A.

[0123] The lower surface layer raw materials include 30% by mass fraction of large-gloss polyester chips and 70% by mass fraction of a commercial silicon type anti-adhesion masterbatch.

[0124] The preparation process of the graphene modified polyester chips A is the same as that in Embodiment 1.

[0125] S2-S4 are the same as those in Embodiment 1.

[0126] Comparative Example 3

[0127] Comparative Example 3 is different from Embodiment 2 only in that the mixing ratio of irregular SiO2 particles in the irregular SiO2 modified anti-adhesion masterbatch with different particle sizes is changed. The specific steps are as follows:

[0128] S1, configuring the upper surface layer, core layer, and lower surface layer raw materials;

[0129] The upper surface layer raw materials include 30% by mass fraction of large-gloss polyester chips and 70% by mass fraction of an irregular SiO2 modified anti-adhesion masterbatch with different particle sizes.

[0130] The raw material of the core layer is graphene modified polyester chips A.

[0131] The lower surface layer raw materials include 30% by mass fraction of large-gloss polyester chips and 70% by mass fraction of an irregular SiO2 modified anti-adhesion masterbatch with different particle sizes.

[0132] In the embodiment, the preparation process of the irregular SiO2 modified anti-adhesion masterbatch with different particle sizes includes:

[0133] 1) Random SiO2 particles with a particle size of 1.5 μm and random SiO2 particles with a particle size of 3.5 μm are premixed in a molar ratio of 1:2 to obtain a particle mixture;

[0134] 2) The particle mixture is added to a reaction kettle containing terephthalic acid, isophthalic acid and ethylene glycol and stirred thoroughly; the molar ratio of terephthalic acid to isophthalic acid is 9:1, the molar ratio of ethylene glycol to the total amount of diacid is 1.25:1, and the mass fraction of the particle mixture is 0.33%; then esterification and dehydration are carried out at a temperature of 250°C, a pressure of 0.25 MPa and a stirring frequency of 25 Hz, and after the water output reaches more than 95%, the pressure is gradually reduced and the temperature is gradually increased to cause pre-polycondensation, and finally the polycondensation reaction is carried out by adjusting the pressure in the kettle to 70 Pa and the temperature to 280°C, after which drawing, cooling and pelletizing are carried out to obtain a different particle size, random SiO2 modified anti-adhesion master batch, and the particle content of the master batch is 3300 ppm.

[0135] The preparation process of the graphene modified polyester chip A is the same as S1.

[0136] S2-S4 are the same as Example 1.

[0137] Comparative Example 4

[0138] The difference between the comparative example and Example 2 is only that the mixing ratio of random SiO2 particles in the different particle size random SiO2 modified anti-adhesion master batch is changed; the specific steps are as follows:

[0139] S1, configure the upper surface layer, core layer, and lower surface layer raw materials;

[0140] The upper surface layer raw materials include 30% by mass of bright polyester chip and 70% by mass of different particle size random SiO2 modified anti-adhesion master batch;

[0141] The raw material of the core layer is graphene modified polyester chip A;

[0142] The lower surface layer raw materials include 30% by mass of bright polyester chip and 70% by mass of different particle size random SiO2 modified anti-adhesion master batch.

[0143] In this example, the preparation process of the different particle size random SiO2 modified anti-adhesion master batch includes:

[0144] 1) Random SiO2 particles with a particle size of 1.5 μm and random SiO2 particles with a particle size of 3.5 μm are premixed in a molar ratio of 2:1 to obtain a particle mixture;

[0145] 2) The particle mixture is added to a reaction kettle containing terephthalic acid, isophthalic acid and ethylene glycol, and stirred thoroughly; the molar ratio of terephthalic acid to isophthalic acid is 9:1, the molar ratio of ethylene glycol to total diacid is 1.25:1, and the mass fraction of the particle mixture is 0.33%; then esterification and dehydration are carried out at a temperature of 250°C, a pressure of 0.25 MPa, and a stirring frequency of 25 Hz, and after the water output reaches more than 95%, the pressure is gradually reduced and the temperature is gradually increased to cause pre-polycondensation, and finally the pressure in the kettle is adjusted to 70 Pa and the temperature is adjusted to 280°C to carry out polycondensation, after which drawing, cooling and pelletizing are carried out to obtain irregular SiO2 modified anti-sticking masterbatch of different particle sizes, and the particle content of the masterbatch is 3300 ppm.

[0146] The preparation process of the graphene modified polyester chip A is the same as S1.

[0147] S2-S4 are the same as Example 1.

[0148] Thin film performance test

[0149] The finished thin films in Examples 1-7 and Comparative Examples 1-4 are tested for performance, and the test items include resistivity, surface roughness, friction coefficient, wetting tension and mechanical properties, and the specific test process is as follows:

[0150] 1) Resistivity: a square sample of 100 mm x 100 mm is cut from the thin film sample, and is connected to the input end button and high voltage end button of the high resistance meter, respectively, and then the test voltage is adjusted to 500 V, and the surface resistance value of the sample is measured and recorded, and each thin film sample is tested in parallel for 3 groups, and the average value is taken.

[0151] 2) Surface roughness: a square sample of 100 mm x 100 mm is cut from the thin film sample and laid on the table, and then the instrument mode is switched to Ra, the test is started and the indicated value is recorded, and each thin film sample is tested in parallel for 3 groups, and the average value is taken.

[0152] 3) Friction coefficient: samples of 250 mm x 100 mm and 80 mm x 50 mm are cut from the thin film sample, respectively, and the large size sample is fixed on the surface of the test table, and the small size sample is fixed on the bottom surface of the slider, then the instrument is started, the slider and the sample film on the platform are pulled at a speed of 100 mm / min to cause relative displacement and keep for 15 s, and finally the static / dynamic friction coefficient value is recorded, and each thin film sample is tested in parallel for 3 groups, and the average value is taken.

[0153] 4) Wetting tension: A 100 mm x 100 mm square sample was cut from the film sample and placed on a coated tool plate. A cotton swab was dipped into the Dynes solution (42-58 mN / m) and wiped across the sample surface while observing the liquid dispersion. If the liquid did not disperse for more than 2 s, the next level of testing was continued. The test was recorded until the time was close to 2 s, and the wetting tension value of the corresponding solution was recorded.

[0154] 5) Tensile strength: A 150 mm long and 15 mm wide strip sample was cut from the film sample. The upper and lower clamps of the tensile tester were used to clamp the short edges of the sample, with a clamp spacing of 100 mm. The instrument was started, and the sample was stretched at a constant speed of 100 mm / min until the sample broke. Finally, the tensile strength value was read in the matching analysis software. Each film sample was tested in three groups in the horizontal and vertical directions, and the average value was taken.

[0155] The test results of Examples 1-7 are shown in Table 1, and the test results of Comparative Examples 1-4 are shown in Table 2.

[0156] Table 1 Test results of films prepared in Examples 1-7

[0157]

[0158] Table 2 Test results of films prepared in Comparative Examples 1-4

[0159]

[0160] As can be seen from Tables 1 and 2, the doping of graphene particles in the core layer can significantly reduce the material resistivity, thereby accelerating the discharge of static charges on the film surface, shortening the charge decay half-life, and avoiding the adverse effects of static electricity on subsequent processing. At the same time, it can be observed that the polyester masterbatch modified by SiO2 particles of different particle sizes and irregular shapes can significantly improve the surface roughness Ra of the film, and the corresponding friction coefficient also decreases to varying degrees, thereby further reducing the amount of static charges generated by friction. Similarly, due to the improvement in roughness, the wetting tension of the film has been greatly improved, which will help the uniformity and firmness of the subsequent coating of the release layer. Finally, the addition of this masterbatch containing particles of different particle sizes and irregular shapes also enhances the overall mechanical properties of the film, indicating that it can further enhance the toughness of the polymer while playing a heterogeneous nucleation role compared to conventional spherical particles. It is worth noting that if the doping proportion of a certain particle size is increased, the roughness of the prepared film does not change significantly, and the corresponding friction coefficient and wetting tension performance are also general, which may be due to the fact that when the proportion of a certain particle is too high, agglomeration is more likely to occur during condensation, resulting in insufficient particle dispersion and affecting the surface properties after film formation.

[0161] In the description of the specification, the description of the terms "one embodiment", "an example", "a specific example" and the like means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any appropriate way in one or more embodiments or examples.

[0162] The basic principles, main features and advantages of the present application are shown and described above. It should be understood by those skilled in the art that the present application is not limited by the above embodiments, and the above embodiments and descriptions in the specification are only to illustrate the principles of the present application. Without departing from the spirit and scope of the present application, various changes and improvements can be made to the present application, and these changes and improvements all fall within the scope of the claimed present application.

Claims

1. A BOPET film for gilding transfer, characterized by, From top to bottom in turn includes: the upper layer, core layer and lower layer; The raw materials of the upper layer and the lower layer are the same, and each includes: (2-4) :(6-8) mass ratio of bright polyester chip and irregular SiO2 modified anti-adhesion masterbatch with different particle sizes; The raw material of the core layer is: graphene modified polyester chip; The irregular SiO2 modified anti-adhesion masterbatch with different particle sizes is prepared by: mixing irregular SiO2 particles with different particle sizes in a molar ratio of 1:1, then stirring with terephthalic acid, isophthalic acid and ethylene glycol, and then esterification and polycondensation; the particle size range of the irregular SiO2 particles is: 1.5-5.0um.

2. A BOPET film for gold stamping transfer according to claim 1, characterized in that, The graphene modified polyester chip is made by melting and blending nano graphene particles and polyethylene terephthalate.

3. A BOPET film for gold blocking transfer according to claim 1, characterized in that, The particle content of the irregular SiO2 modified anti-adhesion masterbatch with different particle sizes is 3300ppm.

4. A BOPET film for gold blocking transfer according to claim 2, characterized in that, The particle size range of the nano graphene particles is: 5-20nm.

5. A BOPET film for gold blocking transfer as claimed in claim 1, wherein, The thickness of the upper layer and the lower layer is 1.1um, and the thickness of the core layer is 9.8um.

6. A process for the preparation of a BOPET film for transfer foiling according to any one of claims 1 to 5, characterized in that, The steps include: S1, after the core layer raw material is pre-crystallized, dried and impurity-removed, it is sent into a single screw extruder for melt extrusion, filtration to obtain a core layer melt; And the upper layer and the lower layer raw materials are respectively sent into a double screw extruder for melt extrusion, vacuum drying and filtration to obtain an upper layer melt and a lower layer melt; S2, the core layer melt, the upper layer melt and the lower layer melt are converged at the die head, cast, and attached to the surface of a low-temperature cold roller under the action of high-voltage electrostatic, forming a polyester thick sheet with a three-layer structure; S3, the polyester thick sheet is put into a longitudinal stretching section, preheated and then longitudinally stretched, and then put into a transverse stretching section for preheating, transverse stretching, heat setting and cooling treatment, forming a biaxially oriented polyester film; S4, the biaxially oriented polyester film enters the traction stage for flattening, thickness measurement and edge trimming, and is wound into a master roll, and finally cut into finished film.

7. A process for the preparation of a BOPET film for gilding transfer according to claim 6, characterized by the fact that, In S3: the preheating temperature of longitudinal stretching is 90℃, the stretching temperature is 110℃, and the stretching ratio is 3.7; the preheating temperature of transverse stretching is 100℃, the stretching temperature is 115℃, the heat setting temperature is 230℃, and the stretching ratio is 3.6; the cooling temperature is 25℃.

8. The use of the BOPET film as claimed in any one of claims 1-5 as a gold stamping carrier in gold stamping transfer.

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