Platinum curing release agent, release film and preparation method thereof

Abstract

The invention discloses a platinum curing release agent, a release film and a preparation method of the release film, and belongs to the technical field of release materials. The platinum curing release agent comprises the following raw materials in parts by mass: 85 parts of siloxane; wherein the ratio of the hexenyl polydimethylsiloxane is more than 80 wt%, and the balance is hydrogen-containing siloxane; 0.8-8 parts of a sulfonic acid acrylic monomer; 0.05 to 2 parts of a pre-catalyst; 0.1-2 parts of a catalyst carrier; 0.1 to 3 parts of an initiator; the catalyst carrier is a multi-walled carbon nanotube; the multi-walled carbon nanotube is any one of a hydroxylated multi-walled carbon nanotube, a carboxylated multi-walled carbon nanotube, an aminated multi-walled carbon nanotube and a graphitized multi-walled carbon nanotube, and the pre-catalyst is a platinum compound. The release film prepared by the invention has good chemical stability and uniformity, relatively low stripping force and good antistatic capability and conductivity.

Description

Technical Field

[0001] The invention relates to the technical field of release materials, and in particular to a platinum-cured release agent, a release film and a preparation method thereof. Background Art

[0002] Release agents are a type of chemical coating material with special functions. They are widely used in the fields of self-cleaning, decoration and protection of electronic devices, adhesives, medical, optical, electronic devices, flexible circuits, etc. Silicone release agents are cross-linked polymers with silicon-oxygen chains as the skeleton. Their surface groups are easily exposed, and they have low polarity, low surface energy, excellent weather resistance and aging resistance. At the same time, silicone polymers have good solubility in commonly used aromatic and aliphatic solvents, low viscous flow activation energy, and good coating performance. They can be applied to the substrate as an extremely thin release coating. The release effect of the silicone coating can also be adjusted within a certain range by changing the cross-linking density of the silicone polymer and the molecular weight and composition of the copolymer. Therefore, silicone release agents can adapt to different product requirements and are currently widely used release agents.

[0003] The hydrosilylation reaction is one of the most important reaction types for the preparation of silicone release agents. This reaction mainly occurs through the addition of unsaturated carbon-carbon bonds (C=C, C≡C) or carbon-nitrogen bonds (C=N, C≡N) to Si-H bonds. The hydrosilylation reaction is usually carried out under the conditions of ultraviolet light, high temperature, peroxide or catalyst. Platinum-based catalysts are commonly used catalysts for hydrosilylation reactions. However, the existing platinum catalyst preparation methods have the disadvantages of high reaction temperature, large catalyst dosage, easy agglomeration, poor stability, low conversion rate and low catalytic selectivity. The commonly used catalyst carrier is carbon black, which is prone to uneven distribution of catalyst particles due to its weak interaction with platinum, thereby affecting the catalytic activity. By-products are released during high-temperature thermal curing, and the curing rate is slow and the degree of crosslinking is uneven. In addition, the use of ultraviolet light or peroxides is prone to self-polymerization of unsaturated hydrocarbon compounds, resulting in reduced selectivity and yield of hydrogenation reactions. In addition, the thickness of ultraviolet light penetration is limited, and the curing effect is poor for thick coatings or systems with fillers. Compared with the above curing methods, visible light curing is efficient, energy-saving, environmentally friendly and economical. However, during the light curing process, the light intensity decays in the thickness direction, and for the part that has been cured, continuous exposure to visible light will cause some molecular bonds to break, and excessive radiation will cause the degree of curing and cross-linking to be too high, causing cracks inside. In addition, the degree of curing of the inner and outer layers is different, forming an isolation layer that makes it difficult to discharge the heat and gas products released in the reaction. All of these will cause the release layer to peel off, the release performance to decrease, and the stability to decrease.

[0004] As an important functional material, release film is widely used in electronic products, optical devices, food processing, chemical and pharmaceutical industries, etc. At present, more stringent requirements are put forward for the strength, peeling force, high temperature resistance, conductivity and acid and alkali resistance of release film. However, the existing release film is easy to lose its antistatic performance in high humidity environment, which limits its application in high precision and high cleanliness environment. The existing technology improves the antistatic performance by adding conductive polymers to the coating, but the existing antistatic materials, such as polyaniline, have poor stability at high temperature, and the antistatic coating formed has insufficient bonding strength with the substrate, which is easy to cause the coating to fall off after long-term use or in high humidity environment. Summary of the invention

[0005] In order to solve the problems of easy agglomeration, poor stability, high loading amount for catalysts such as Pt, complicated loading method caused by the use of traditional catalyst carriers in the existing silane addition method, and low chemical stability of the existing release film due to the high curing temperature, the present invention provides a platinum-cured release agent, a release film and a preparation method thereof.

[0006] The technical solution adopted by the present invention is: A platinum-curing release agent comprises the following raw materials in parts by weight: Siloxane, 85 parts; of which hexenyl polydimethylsiloxane accounts for more than 80 wt%, and the rest is hydrogen-containing siloxane; Sulfonic acid acrylic monomer, (0.8 – 8) parts; Precatalyst, (0.05 – 2) parts; Catalyst support, (0.1 – 2) parts; Initiator, (0.1 – 3) parts; The catalyst carrier is a multi-walled carbon nanotube, and the pre-catalyst is a platinum compound; The multi-walled carbon nanotubes are any one of hydroxylated multi-walled carbon nanotubes, carboxylated multi-walled carbon nanotubes, aminated multi-walled carbon nanotubes and graphitized multi-walled carbon nanotubes.

[0007] The structural formula of hexenyl polydimethylsiloxane is:

[0008] The structural formula of hydrogen siloxane is:

[0009] Furthermore, the number average molecular weight of the siloxane is 200,000-800,000.

[0010] Furthermore, the sulfonic acid acrylic monomer is at least one of 2-acrylamido-2-methyl-1-propane sulfonic acid, ethyl methacrylate sulfonate and sodium allyloxybenzene sulfonate.

[0011] Furthermore, the platinum compound is K 2 PtCl 4 , H 2 PtCl 6 6H 2 O.K 2 PtCl 6 、Pt(NH 3 ) 2 Cl 2 and K 2 [Pt(CN) 4 ]·3H 2 Any one of O.

[0012] Furthermore, the initiator is any one of phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide, benzophenone and 2-hydroxy-2-methyl-1-phenyl-1-propanone.

[0013] Furthermore, the molecular structure of the catalyst carrier is as follows: .

[0014] A release film comprises a substrate and any one of the above-mentioned platinum-cured release agents coated on one side of the substrate.

[0015] Furthermore, the material of the substrate is PET, and the thickness of the release agent layer is 20-48 μ m.

[0016] The method for preparing any one of the above release films comprises the following steps: (1) Siloxane, precatalyst and catalyst carrier are mixed according to the proportion and stirred for reaction for a certain period of time under visible light irradiation, and then sulfonic acid acrylic monomer and initiator are added and mixed again to obtain a release agent; (2) The release agent prepared in step (1) is uniformly coated on the substrate with a certain thickness, and cured at a certain temperature to obtain a release film.

[0017] The reaction principle of curing is as follows: .

[0018] The structural advantages of sulfonic acid acrylic monomers are mainly: (1) Due to the introduction of rigid large side groups (the main side groups are –CONHC(CH 3 ) 2 CH 2 SO 3 – ) connection, which improves the thermal stability of the release film; (2) the –SO 3 –Group. Theoretically speaking from the charge theory, for the sulfonic acid group, the two π bonds between S and O and the three O atoms with strong electronegativity share one negative charge, making the charge density around the group accumulate, thus enhancing its hydration property and not being sensitive to cations in the external environment. Therefore, this release film has excellent anti-salt performance; (3) The sulfonic acid group is a strong anionic group, with strong hydrophilic and electrostatic repulsion effects and can effectively prevent the molecular chain from curling, improving the viscosity of the release agent; (4) The sulfonic acid group can effectively inhibit the hydrolysis of the polymer at high temperatures, protect the amide group and thus improve the temperature resistance of the release film; (5) Reduces the dosage of siloxane in the release agent. By controlling the ratio of the two siloxanes to the sulfonic acid-based acrylic monomer, that is, adjusting the ratio of x / y / z, the performance of the release film can be regulated.

[0019] Further preferably, in step (1), the wavelength of the visible light ≥ 420 nm, and the stirring reaction time is 0.5 - 2 hours. The purpose of the stirring reaction under visible light with a wavelength ≥ 420 nm is to ensure the formation of the catalyst. Its irradiation time is generally not less than 0.5 hours and not more than 2 hours. Too long a time will cause waste of energy.

[0020] To ensure that the curing reaction proceeds completely, further preferably, in step (2), the environmental temperature of the curing reaction is 25–45 °C, and the reaction time is 1.3–8 hours.

[0021] The beneficial effects of the present invention: 1. The functional groups on the surface of the surface-functionalized multi-walled carbon nanotubes strengthen their interaction with Pt, can improve the dispersibility of the catalyst and its compatibility with other materials, thus avoiding the agglomeration of the catalyst and reducing the catalyst loading amount; and the multi-walled carbon nanotubes have a large specific surface area, good stability and conjugated structure, can effectively adsorb and stabilize the catalyst, thus improving the catalytic efficiency; the multi-walled carbon nanotubes have excellent electrical conductivity and mechanical properties. Using the electrical conductivity of the carbon nanotubes can prevent the generation and accumulation of static electricity on the surface of the release film and enhance the electrical conductivity of the release film.

[0022] 2. The present invention uses a mild room-temperature curing method to in-situ form a Pt-based catalyst on the multi-walled carbon nanotubes. The formed Pt catalyst has the advantages of low loading amount, low curing temperature, high catalytic activity, high selectivity, etc. At the same time, the Pt catalyst can also cooperate with other active components to optimize the comprehensive performance of the release film.

[0023] 3. The present invention introduces sulfonic acid acrylic monomers, which can reduce the amount of silicone used, adjust the hydrophilicity of the release agent, adjust the viscosity of the release agent, and use its charge to reduce the catalyst repulsion in the reaction, so that the reaction is more complete and less by-products are generated; on the other hand, after the sulfonic acid acrylic monomers are introduced, the thermal stability of the release film is improved due to the interaction of van der Waals forces and hydrogen bonds, and it has a certain contribution to the surface flatness of the release film, so that it has good adaptability to use in special environments.

[0024] 4. In-situ photodeposition is used to deposit Pt onto the carrier. Unlike chemical reduction and hydrothermal reduction technologies, in-situ photodeposition does not require external energy (no reducing agent is added, and no heat energy is consumed). Micro-nano functional materials are obtained by photoexciting pre-catalyst materials, which effectively reduces pollution to materials, reduces production costs, and obtains catalyst materials without damage and with good stability. At the same time, the curing process is not affected by light, and the preparation of release films can effectively achieve rapid curing, low cost, and controllable process, so that the product release layer is stable and does not peel off, and the release performance and stability are improved.

[0025] In general, the present invention utilizes a room temperature curing method to in-situ photodeposit a Pt-based catalyst on multi-walled carbon nanotubes, and prepares a release film by low-loading room temperature curing. The method has the advantages of simple operation, strong selectivity, and a safe and environmentally friendly process. It can produce a release film with excellent performance in a more economical manner, and the produced release film has the characteristics of uniform surface, low peeling force, adjustable release force, good conductivity, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a scanning electron microscope image of the functionalized multi-walled CNT used in Example 1.

[0027] Figure 2 This is a scanning electron microscope image of the CNT-Pt prepared in Example 1.

[0028] Figure 3 This is a 3D height map of the cured release film A prepared in Example 1.

[0029] Figure 4 The hydrogen nuclear magnetic resonance spectra of the curable release films prepared in Example 1 and Comparative Examples 1-5 before and after curing.

[0030] Figure 5 The infrared spectra of the curable release films prepared in Example 1 and Comparative Examples 1-5 before and after curing.

[0031] Figure 6 Thermal analysis diagrams of the cured release films prepared in Example 1 and Comparative Example 1.

[0032] Figure 7The hydrogen nuclear magnetic resonance spectra of the curable release film A prepared in Example 1 before and after acid-base treatment.

[0033] Figure 8 The infrared spectra of the curable release film A prepared in Example 1 before and after acid-base treatment. DETAILED DESCRIPTION

[0034] The technical solution of the present invention is described in detail below through specific embodiments, but the protection scope of the present invention is not limited to the embodiments.

[0035] The raw materials used in the following examples and comparative examples are all commercially available.

[0036] Hexenyl polydimethylsiloxane was purchased from Dow Corning (PC183) and was used after removing the solvent.

[0037] Hydrogen-containing siloxane was purchased from Dow Corning (HH127) and was used after removing the solvent.

[0038] The vector was purchased from Beijing Inokai Co., Ltd. (A57667).

[0039] The precatalyst was purchased from Jiangsu Xianfeng Nanomaterial Technology Co., Ltd.

[0040] Sulfonic acid acrylic monomers: 2-acrylamido-2-methyl-1-propane sulfonic acid (A800508), ethyl methacrylate sulfonate (E808775) and / or sodium allyloxybenzene sulfonate (S818450) were purchased from MacLean Company.

[0041] Initiator: Phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide (511447), benzophenone (8018010005), and 2-hydroxy-2-methyl-1-phenyl-1-propanone (405655) were purchased from MacLean Company. Example 1

[0042] The preparation method of the curing release film A is as follows: (1) 3.0 g of hexenyl polydimethylsiloxane with a number average molecular weight of about 250,000 and 0.5 g of hydrogen-containing siloxane, 0.028 g of K 2 PtCl 4 , 0.05 g of graphitized multi-walled CNTs were mixed evenly, stirred for 1 hour under visible light (wavelength ≥ 420 nm), and then 0.2 g of 2-acrylamido-2-methyl-1-propane sulfonic acid and 0.12 g of initiator phenyl bis(2,4,6-trimethylbenzoyl)phosphine oxide were added, and the above components were mixed evenly to obtain release agent A; (2) The release agent A is evenly coated on the surface of the PET substrate layer and reacted at 40°C for 2.5 hours to obtain a cured release film A, the thickness of which is 20 ± 2 μ m.

[0043] The scanning electron microscope image of the graphitized multi-walled CNT used in this example is shown in Figure 1 .from Figure 1 It can be seen that the raw material multi-walled graphitized CNT has no obvious agglomeration, has a larger specific surface area, exposes more active sites, and is more conducive to the loading of the catalyst.

[0044] In order to examine the loading effect of multi-walled CNTs, 0.028 g K 2 PtCl 4 , 0.05 g of graphitized multi-walled CNT was mixed evenly, and stirred for 1 hour under visible light (wavelength ≥ 420 nm) to obtain a carrier-catalyst CNT-Pt. The scanning electron microscopy image of the obtained carrier-catalyst is shown in Figure 2 .from Figure 2 It can be seen that this method can successfully load Pt on carbon nanotubes, and there is no agglomeration and uniform dispersion after the reaction.

[0045] The prepared curable release film A was subjected to EDS spectrum test and analysis, and the amount of catalyst Pt supported by in-situ photodeposition was 26 wt % relative to the added carbon nanotube carrier.

[0046] The surface morphology of the prepared curing release film A was analyzed, and the results are shown in Figure 3 ;from Figure 3 It can be found that the surface thickness of the prepared cured release film A is uniform and there is no obvious protrusion.

[0047] The prepared photocurable release film A was subjected to an acid-base stability test. The test method was as follows: After soaking it in a 0.1M hydrochloric acid solution and a 0.1M sodium hydroxide solution for 12 hours, it was taken out and washed with deionized water, and then subjected to NMR and IR tests respectively. The test results are shown in Figure 7 and Figure 8 .from Figure 7 and Figure 8 It can be found that after being soaked in acid and alkali, the characteristic peaks of the release film have no obvious changes, indicating that the release film prepared in Example 1 has good acid-base stability. Example 2

[0048] The preparation method of the curing release film B is as follows: (1) 7.6 g of hexenyl polydimethylsiloxane with a number average molecular weight of about 350,000 and 1.3 g of hydrogen-containing siloxane, 0.046 g of K 2PtCl 6 , 0.02 g of carboxylated multi-walled CNT was mixed evenly, stirred for 1 hour under visible light (wavelength ≥ 420 nm), and then 0.21 g of sodium allyloxybenzene sulfonate and 0.268 g of initiator benzophenone were added, and the above components were mixed evenly to obtain release agent B; (2) The release agent B is evenly coated on the surface of the PET substrate layer and reacted at a temperature of 25°C for 8 hours to obtain a cured release film B, the thickness of which is 20 ± 2 μ m. Example 3

[0049] The preparation method of the curing release film C is as follows: (1) 9.8 g of hexenyl polydimethylsiloxane with a number average molecular weight of about 500,000 and 2.1 g of hydrogen-containing siloxane, 0.069 g of H 2 PtCl 6 6H 2 O, 0.035 g carboxylated multi-walled CNT were mixed evenly, stirred for 1 h under visible light (wavelength ≥ 420 nm), and then 0.78 g 2-acrylamido-2-methyl-1-propane sulfonic acid was added, 260 μ L initiator 2-hydroxy-2-methyl-1-phenyl-1-propanone, the above components are mixed evenly to obtain release agent C; (2) The release agent C was evenly coated on the surface of the PET substrate layer and reacted at 28°C for 6.5 hours to obtain a cured release film C, the thickness of which was 36 ± 2 μ m. Example 4

[0050] The preparation method of the curing release film D is as follows: (1) 8.6 g of hexenyl polydimethylsiloxane with a number average molecular weight of about 750,000, 3.4 g of hydrogen-containing siloxane, and 0.033 g of Pt (NH 3 ) 2 Cl 2 , 0.054 g of hydroxylated multi-walled CNT was mixed evenly, stirred for 1 hour under visible light (wavelength ≥ 420 nm), 0.13 g of ethyl methyl propylene sulfonate and 0.11 g of 2-acrylamido-2-methyl-1-propane sulfonic acid, and 0.236 g of initiator benzophenone were added, and the above components were mixed evenly to obtain release agent D; (2) The release agent D was evenly coated on the surface of the PET substrate layer and reacted at a temperature of 32°C for 5.2 hours to obtain a cured release film D, the thickness of which was 32 ± 2 μ m. Example 5

[0051] The preparation method of the curing release film E is as follows: (1) 7.5 g of hexenyl polydimethylsiloxane with a number average molecular weight of about 800,000 and 2.9 g of hydrogen-containing siloxane, 0.033 g of K 2 [Pt(CN) 4 ]·3H 2 O, 0.025 g of amino multi-walled CNT were mixed evenly, stirred for 1 hour under visible light (wavelength ≥ 420 nm), 0.47 g of ethyl methyl propylene sulfonate, 0.165 g of initiator phenyl bis (2, 4, 6-trimethylbenzoyl) phosphine oxide and 0.125 g of benzophenone were added, and the above components were mixed evenly to obtain a release agent E; (2) The release agent E was evenly coated on the surface of the PET substrate layer and reacted at a temperature of 35°C for 3.8 hours to obtain a cured release film E, the thickness of which was 38 ± 2 μ m. Example 6

[0052] The preparation method of the curing release film F is as follows: (1) 6.8 g of hexenyl polydimethylsiloxane with a number average molecular weight of about 750,000 and 0.26 g of hydrogen-containing siloxane, 0.021 g of H 2 PtCl 6 6H 2 O, 0.03 g carboxylated multi-walled CNT were mixed evenly, stirred for 1 h under visible light (wavelength ≥ 420 nm), 0.35 g ethyl methyl propylene sulfonate was added, 126 μ L initiator 2-hydroxy-2-methyl-1-phenyl-1-propanone, the above components are mixed evenly to obtain release agent F; (2) The release agent F was evenly coated on the surface of the PET substrate layer and reacted at 38°C for 3.2 hours to obtain a cured release film F, the thickness of which was 41 ± 2 μ m. Example 7

[0053] The preparation method of the curing release film G is as follows: (1) 5.4 g of hexenyl polydimethylsiloxane with a number average molecular weight of about 720,000 and 0.13 g of hydrogen-containing siloxane and 0.015 g of H 2 PtCl 6 6H 2O, 0.025 g of amino multi-walled CNT were mixed evenly, stirred for 1 hour under visible light (wavelength ≥ 420 nm), 0.16 g of 2-acrylamido-2-methyl-1-propane sulfonic acid and 0.09 g of sodium allyloxybenzenesulfonate, 0.135 g of initiator phenyl bis (2, 4, 6-trimethylbenzoyl) phosphine oxide were added, and the above components were mixed evenly to obtain release agent G; (2) The release agent G is evenly coated on the surface of the PET substrate layer and reacted at 42°C for 2 hours to obtain a cured release film F, the thickness of which is 35 ± 2 μ m. Example 8

[0054] The preparation method of the curing release film H is as follows: (1) 6.5 g of hexenyl polydimethylsiloxane with a number average molecular weight of about 600,000 and 0.21 g of hydrogen-containing siloxane, 0.021 g of K 2 PtCl 4 , 0.15 g of graphitized multi-walled CNT was mixed evenly, stirred for 1 h under visible light (wavelength ≥ 420 nm), and then 0.32 g of sodium allyloxybenzene sulfonate was added, 158 μ L initiator olefin 2-hydroxy-2-methyl-1-phenyl-1-propanone, the above components are mixed evenly to obtain release agent H; (2) The release agent H was evenly coated on the surface of the PET substrate layer and reacted at 45°C for 1.3 hours to obtain a cured release film H, the thickness of which was 36 ± 2 μ m.

[0055] Comparative Example 1 (1) 3.0 g of hexenyl polydimethylsiloxane with a number average molecular weight of about 250,000 and 0.5 g of hydrogen-containing siloxane, 0.028 g of K 2 PtCl 4 , 0.05 g of graphitized multi-walled CNT was mixed evenly, stirred for 1 hour under visible light (wavelength ≥ 420 nm), and then 0.12 g of initiator phenyl bis (2, 4, 6-trimethylbenzoyl) phosphine oxide was added, and the above components were mixed evenly to obtain comparative release agent 1; (2) The comparative release agent 1 was evenly coated on the surface of the PET substrate layer, and the reaction time was 2.5 hours at a temperature of 40° C., thereby obtaining a comparative cured release film 1.

[0056] The release films prepared in Example 1 and Comparative Example 1 were subjected to thermogravimetric analysis tests, and the results are shown in Figure 6 . Figure 6It shows that the addition of sulfonic acid acrylic acid monomer can effectively increase the thermal decomposition temperature of the release film, and the residual mass is the highest after high-temperature heating, indicating that the stability of the release film of the present application is significantly improved.

[0057] Comparative Example 2 (1) 3.0 g of hexenyl polydimethylsiloxane with a number average molecular weight of about 250,000 and 0.5 g of hydrogen-containing siloxane, 0.028 g of K 2 PtCl 4 , 0.05 g of graphitized multi-walled CNT was mixed evenly, stirred for 1 hour under visible light (wavelength ≥ 420 nm), and then 0.2 g of 2-acrylamido-2-methyl-1-propane sulfonic acid was added, and the above components were mixed evenly to obtain comparative release agent 2; (2) The comparative release agent 2 was evenly coated on the surface of the PET substrate layer, and the reaction time was 2.5 hours at a temperature of 40° C., thereby obtaining a comparative cured release film 2.

[0058] Comparative Example 3 (1) 3.0 g of hexenyl polydimethylsiloxane with a number average molecular weight of about 250,000, 0.5 g of hydrogen-containing siloxane, and 0.05 g of graphitized multi-walled CNT were mixed evenly, and stirred for 1 hour under visible light (wavelength ≥ 420 nm), and then 0.2 g of 2-acrylamido-2-methyl-1-propane sulfonic acid and 0.12 g of initiator phenyl bis (2, 4, 6-trimethylbenzoyl) phosphine oxide were added, and the above components were mixed evenly to obtain comparative release agent 3; (2) The comparative release agent 3 was evenly coated on the surface of the PET substrate layer, and the reaction time was 2.5 hours at a temperature of 40° C., thereby obtaining a comparative cured release film 3.

[0059] Comparative Example 4 (1) 3.0 g of hexenyl polydimethylsiloxane with a number average molecular weight of about 250,000 and 0.5 g of hydrogen-containing siloxane, 0.028 g of K 2 PtCl 4 Mix well, stir for 1 hour under visible light (wavelength ≥ 420 nm), then add 0.2 g of 2-acrylamido-2-methyl-1-propane sulfonic acid and 0.12 g of initiator phenyl bis(2,4,6-trimethylbenzoyl)phosphine oxide, and mix the above components well to obtain comparative release agent 4; (2) The comparative release agent 4 was evenly coated on the surface of the PET substrate layer, and the reaction time was 2.5 hours at a temperature of 40° C., thereby obtaining a comparative cured release film 4.

[0060] Comparative Example 5 (1) 3.0 g of hexenyl polydimethylsiloxane with a number average molecular weight of about 250,000 and 0.5 g of hydrogen-containing siloxane, 0.028 g of K 2 PtCl 4 , 0.05 g of graphitized multi-walled CNT was mixed evenly, stirred at 150° C. for 3 hours, then 0.2 g of 2-acrylamido-2-methyl-1-propane sulfonic acid and 0.12 g of initiator phenyl bis(2,4,6-trimethylbenzoyl)phosphine oxide were added, and the above components were mixed evenly to obtain comparative release agent 5; (2) The comparative release agent 5 was evenly coated on the surface of the PET substrate layer and reacted at 40°C for 2.5 hours to obtain a comparative cured release film 5, the thickness of which was 20 ± 2 μ m.

[0061] The curable release films prepared in Example 1 and Comparative Examples 1-5 were characterized, and the H NMR spectra showed Figure 4 , the results of infrared test are shown in Figure 5 .

[0062] from Figure 4 It can be found that since no monomer is added in Comparative Example 1, almost no curing reaction occurs. After curing, for Example 1, the signal at δ4.50 ppm is significantly weakened, corresponding to the methylene proton signal at the end of the chain, and the signal at δ1.55 ppm is significantly weakened, corresponding to the breakage of -CH=CH-, indicating that the curing reaction is proceeding. The signal at δ2.23 ppm is significantly enhanced compared with Comparative Examples 3 and 4, indicating that the addition of pre-catalyst and catalyst carrier can effectively promote the forward progress of the curing reaction.

[0063] from Figure 5 It can be found that after the release film of Example 1 is subjected to addition reaction with the platinum catalyst, the 2167 cm-1 peak of the –Si-H bond in the raw siloxane is -1 The infrared absorption band at 1631 cm -1 The infrared absorption band at 4° disappears, indicating that the curing reaction occurs.

[0064] The resistivity of the cured release films obtained in Examples 1-8 and Comparative Examples 1-5 was tested by a thin film square resistance four-probe method. The results are shown in Table 1.

[0065]

[0066] It can be seen from the resistivity data in Table 1 that compared with Comparative Example 4 without adding a carbon nanotube carrier, the resistivity of Examples 1-8, Comparative Examples 1-3 and Comparative Example 5 is significantly reduced, indicating that the addition of the carbon nanotube carrier can make the release film have good conductivity.

[0067] The peeling force, roughness, contact angle and thickness of the cured release films obtained in Examples 1-8 and Comparative Examples 1-5 were tested, and the results are shown in Table 2. The peeling force test adopted the standard: GB / T 25256-2010; the thickness test adopted the standard: ASTM D882-18-2018.

[0068] The curing conditions of the release films prepared in Examples 1-8 and Comparative Examples 1-5 are shown in Table 3.

[0069]

[0070]

[0071] From the results of the extreme differences in roughness and thickness in Table 2, it can be seen that the surface of the release film provided by the present invention is smooth, and the roughness and thickness are evenly distributed.

[0072] The comparison results of Comparative Examples 1-8 show that, combined with the results of Comparative Example 1, the presence of sulfonic acid acrylic monomers has a great influence on the peeling force, but the type of sulfonic acid acrylic monomers has little effect on the peeling force performance. In addition, the use of different proportions of siloxane also has an effect on the peeling force of the release film.

[0073] By comparing the water contact angle results of the release films obtained in Examples 1 to 8 with those of Comparative Example 1, it can be seen that the sulfonic acid acrylic monomer introduced in the present invention can improve the hydrophilicity of the release film.

[0074] From the comparison results of Examples 1 to 8 and Comparative Example 2, it can be seen that the absence of the initiator has a significant impact on the peeling force, roughness, and conductivity.

[0075] From the comparison results of Examples 1 to 8 and Comparative Example 3, it can be seen that the absence of the addition of the pre-catalyst has a greater impact on the peeling force and the roughness.

[0076] From the comparison results of Comparative Examples 1-8 and Comparative Example 4, it can be seen that the absence of the carrier has a significant impact on the peeling force, roughness, and conductivity.

[0077] From the comparison results of Examples 1 to 8 and Comparative Example 5, it can be seen that the traditional method of loading the platinum catalyst has a great influence on the peeling force, roughness and conductivity.

[0078] As can be seen from Table 3, from the comparison results of Comparative Examples 1-8 and Comparative Examples 1-5, it can be seen that during the curing process, as the temperature changes in the range of 25-45°C, the curing time fluctuates in the range of 1.3-8 h, and the overall curing time is shortened as the curing temperature increases.

[0079] Combined with the above analysis, it can be seen that the ratio of siloxane to sulfonic acid acrylic monomer and carrier will affect the performance of the release film, and it is a comprehensive and systematic process. In general, the release film provided by the present invention has controllable and low peeling force, good antistatic ability and conductivity, and good chemical stability, which can meet the requirements of electronic products, optical devices, food processing, chemical and pharmaceutical industries.

[0080] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A platinum-curing release agent, characterized in that: Including the following raw materials by weight: Siloxane, 85 parts; of which hexenyl polydimethylsiloxane accounts for more than 80wt%, and the rest is hydrogen-containing siloxane; Sulfonic acid acrylic monomer, (0.8–8) parts; precatalyst, (0.05–2) parts; Catalyst support, (0.1–2) parts; Initiator, (0.1–3) parts; The catalyst carrier is a multi-walled carbon nanotube, and the pre-catalyst is a platinum compound; The multi-walled carbon nanotube is any one of hydroxylated multi-walled carbon nanotube, carboxylated multi-walled carbon nanotube, amino multi-walled carbon nanotube and graphitized multi-walled carbon nanotube.

2. A platinum-curing release agent according to claim 1, characterized in that: The number average molecular weight of the siloxane is 200,000-800,000.

3. A platinum-curing release agent according to claim 1, characterized in that: The sulfonic acid acrylic monomer is at least one of 2-acrylamido-2-methyl-1-propane sulfonic acid, ethyl methacrylate sulfonate and sodium allyloxybenzene sulfonate.

4. A platinum-curing release agent according to claim 1, characterized in that: The platinum compound is any one of K2PtCl4, H2PtCl6·6H2O, K2PtCl6, Pt(NH3)2Cl2 and K2[Pt(CN)4]·3H2O.

5. A platinum-curing release agent according to claim 1, characterized in that: The initiator is at least one of phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide, benzophenone and 2-hydroxy-2-methyl-1-phenyl-1-propanone.

6. A platinum-curing release agent according to claim 1, characterized in that: The molecular structural formula of the catalyst carrier is as follows: 。 7. A release film, characterized in that: The invention comprises a substrate and a platinum-curing release agent according to any one of claims 1 to 6 coated on one side of the substrate.

8. The release film according to claim 7, characterized in that: The material of the substrate is PET, and the thickness of the release agent layer is 20–48 μ m.

9. The method for preparing the release film according to claim 8 or 7, characterized in that: The following steps are involved: (1) Siloxane, precatalyst and catalyst carrier are mixed according to the proportion and stirred for reaction for a certain period of time under visible light irradiation, and then sulfonic acid acrylic monomer and initiator are added and mixed again to obtain a release agent; (2) The release agent prepared in step (1) is uniformly coated on the substrate with a certain thickness, and cured at a certain temperature to obtain a release film.

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