Single-sided release film and preparation method thereof

Abstract

The invention discloses a single-sided release film and a preparation method thereof, and belongs to the technical field of single-sided release films. The release film consists of 100 parts of a base film material, 5-20 parts of a release agent, 1-10 parts of a stabilizer, 0.5-5 parts of a cross-linking agent and 0.1-2 parts of a dispersing agent. Wherein the stabilizer is a stabilizer containing a deuterated group and a conjugated aromatic heterocyclic structure, phenyl / thienyl and deuterated tert-butyl in the molecular structure have a synergistic effect, and oxidation reaction is inhibited through a dual mechanism of free radical capture and physical steric hindrance. According to the preparation method, a compact cross-linked network is formed by adopting a micro gravure coating process and combining gradient heating curing and corona treatment. Experiments show that the deuterated phenyl-containing single-sided release film has high surface impedance stability after being aged for 200 days. The single-sided release film has the characteristics of excellent antistatic durability, high light transmittance and weather resistance, and is particularly suitable for the field of protection of optical display devices.

Description

Technical Field

[0001] The present invention relates to the technical field of single-sided release films, and in particular to a single-sided release film and a preparation method thereof. Background Art

[0002] Single-sided release film is a material widely used in various industrial and electronic fields, playing a key role in the production and use of tapes, labels, optical films, etc. However, current single-sided release films have many problems in practical applications, especially in terms of oxidation resistance and stability.

[0003] Traditional single-sided release films are susceptible to oxidation upon exposure to oxygen. This is primarily due to the organic components in the film, such as certain release agents, which react chemically with oxygen at room temperature or at a certain temperature. This can lead to a gradual deterioration in the film's surface properties, such as changes in surface energy, which can weaken the release effect and compromise the otherwise excellent peeling properties. For example, in the adhesive tape industry, oxidation can cause abnormal changes in the adhesion between the tape and the release film, making it difficult to peel the tape, impacting production efficiency and product quality.

[0004] Single-sided release films also face challenges in terms of stability. For one thing, changes in temperature and humidity can have an impact. When the ambient temperature rises, the polymer substrate in the release film may accelerate the movement of molecular chains, causing the release agent to migrate or volatilize from the substrate surface, making the release film's performance unstable. Furthermore, changes in humidity, such as in high-humidity environments, can cause moisture to penetrate the release film and interact with the release agent or substrate, disrupting the film's microstructure and interfacial bonding, affecting its overall stability. Furthermore, over time, the various components in the release film may undergo physical or chemical changes. For example, the compatibility between the release agent and the substrate may deteriorate, leading to delamination or precipitation, making it impossible to maintain the release film's performance in an ideal state.

[0005] Therefore, in order to solve the problems of single-sided release films' low oxidation resistance and poor stability, it is particularly urgent to develop new single-sided release films and their preparation methods, which are also of great significance in industrial applications. Summary of the Invention

[0006] The purpose of the present invention is to address the problems existing in the prior art and provide a single-sided release film and a preparation method thereof that is resistant to oxidation, has good stability, excellent release performance and a simple preparation process.

[0007] To achieve the above object, the technical solution adopted by the present invention is: a single-sided release film, characterized in that it comprises the following components in parts by weight: 100 parts of base film material, 5-20 parts of release agent, 1-10 parts of stabilizer, 0.5-5 parts of cross-linking agent, and 0.1-2 parts of dispersant;

[0008] The structure of the stabilizer is as shown in Formula 1:

[0009]

[0010] R1 is selected from the group consisting of phenyl, furyl, thienyl, methyl, ethyl, tert-butyl, deuterated phenyl, deuterated tert-butyl, and deuterated methyl;

[0011] Or the R1 is selected from: phenyl, furyl, thienyl substituted by methyl, ethyl, tert-butyl, deuterated tert-butyl, deuterated methyl.

[0012] Furthermore, the stabilizer is selected from any one of the compounds shown in the following structures:

[0013]

[0014] The D represents deuterium.

[0015] Furthermore, the synthetic route of the stabilizer is:

[0016]

[0017] In the first step, raw materials 1 and 2 are synthesized through Williamson ether synthesis reaction to obtain intermediate 1;

[0018] In the second step, intermediate 1 and raw material 3 are synthesized through substitution reaction to obtain intermediate 2;

[0019] In the third step, intermediate 2 is synthesized by hydroxylamine to obtain a stabilizer.

[0020] Furthermore, the base film material is selected from at least one of polyimide, polyethylene terephthalate or polyethylene naphthalate, and has a thickness of 25-125 μm.

[0021] Furthermore, the release agent is selected from at least one of silicone resin, fluorocarbon resin, and acrylate resin.

[0022] Furthermore, the organic silicone resin is polydimethylsiloxane.

[0023] Furthermore, the fluorocarbon resin is perfluoropolyether or tetrafluoroethylene-hexafluoropropylene copolymer.

[0024] Furthermore, the acrylic resin is polymethyl methacrylate or polybutyl acrylate.

[0025] Furthermore, the cross-linking agent is at least one of a polyisocyanate compound, an epoxy compound or a silane coupling agent;

[0026] The polyisocyanate compound is selected from at least one of hexamethylene diisocyanate, isophorone diisocyanate and toluene diisocyanate.

[0027] Furthermore, the epoxy compound is bisphenol A epoxy resin or alicyclic epoxy resin.

[0028] Furthermore, the silane coupling agent is γ-glycidyloxypropyltrimethoxysilane or methyltrimethoxysilane.

[0029] Furthermore, the dispersant is at least one of a phosphate surfactant and an anionic dispersant.

[0030] Furthermore, the phosphate surfactant is alkylphenol polyoxyethylene ether phosphate or fatty alcohol polyoxyethylene ether phosphate.

[0031] Furthermore, the anionic dispersant is sodium dodecylbenzenesulfonate or sodium polyacrylate.

[0032] A method for preparing a single-sided release film comprises the following steps:

[0033] S1. The release agent, stabilizer, crosslinker and dispersant are added to an organic solvent and mixed to form a release fluid;

[0034] S2. Coating the release liquid on one side of the base film material to form a wet film;

[0035] S3. Staged curing: pre-curing at 50-80°C for 1-5 minutes, and then final curing at 100-150°C for 10-25 minutes.

[0036] S4. The S3 is subjected to aging treatment, and is allowed to stand at 25-40°C for 12-48 hours, and then the surface is subjected to corona treatment to obtain the finished product.

[0037] Furthermore, the coating in S2 adopts a micro-gravure coating process, the coating speed is controlled to be 5-20 m / min, and the wet film thickness is 5-50 μm.

[0038] Furthermore, the final curing stage in S3 adopts a gradient temperature increase mode, increasing the temperature from 80°C to 150°C at a rate of 2-5°C / min.

[0039] Furthermore, the surface is corona treated with a treatment power of 50-300W·min / m 2 , so that its surface tension reaches 38-45mN / m.

[0040] Furthermore, the organic solvent is selected from: toluene or tetrahydrofuran.

[0041] The parent core structure of the stabilizer described in the present invention contains a group composed of a conjugated system with strong electron delocalization ability, which can capture free radicals and inhibit the oxidation chain reaction of the release agent and the base film material. The bulky substituents such as tert-butyl and deuterated tert-butyl isolate oxygen and moisture through physical steric hindrance, thereby reducing the oxidation reaction rate. The group containing heteroatoms (such as oxygen in furyl and sulfur in thienyl) forms intermolecular forces with the polar components in the antistatic coating, reducing the migration or phase separation of the coating components. The bond energy of the CD bond is higher than that of the C-H bond, and it is less likely to break under high temperature or ultraviolet radiation, significantly slowing down the thermal decomposition or photodegradation of the stabilizer itself. The deuterated free radical (D·) generated after the CD bond of the deuterated phenyl group breaks is less active than the H· free radical, which can further inhibit the propagation of the free radical chain reaction.

[0042] The stabilizer's core structure preferentially reacts with oxygen, protecting the silicone and antistatic agent in the release agent from oxidation and preventing the resulting damage to the conductive network. The deuterated groups inhibit the stabilizer's own decomposition, ensuring its long-term stability in the coating, maintaining uniform dispersion of the antistatic agent and the integrity of the conductive pathway.

[0043] The high glass transition temperature of the polyimide (PI) or PET base film described in the present invention is combined with the low surface energy of the silicone release agent to provide a balance between thermal stability and release performance. The base film thickness is regulated by regulating the mechanical strength to avoid uneven coating caused by stress deformation during the coating process. The polyisocyanate crosslinker reacts with the -Si-OH group of the release agent to form a three-dimensional network structure, anchoring the stabilizer in the coating and reducing its volatilization or migration. The phosphate dispersant maintains the dispersion of the antistatic agent nanoparticles through electrostatic repulsion, avoiding resistance fluctuations caused by agglomeration. The gradient temperature curing allows the crosslinking reaction to proceed in stages, ensuring that the stabilizer molecules are arranged in an orderly manner to form a dense protective layer. The corona treatment generates polar groups through surface oxidation, enhancing the adhesion of the coating to the base film.

[0044] The stabilizer described in this invention leverages the radical-trapping capabilities of its core structure and the deuterated anti-decomposition properties of deuterium substitution, creating a synergistic crosslinked network and dispersed system to create a long-lasting, stable antistatic coating protection mechanism. Its irreplaceable nature stems from its precise molecular-level design, achieving a triple breakthrough in antioxidant performance, migration resistance, and system compatibility, unmatched by traditional antioxidants.

[0045] Compared with the prior art, the present invention has the following beneficial effects:

[0046] 1. Improved long-term antioxidant performance: Through the synergistic effect of the conjugated system and deuterated groups in the stabilizer molecules, efficient free radical capture and oxygen isolation are achieved, significantly delaying the oxidative degradation of the release film, and solving the pain point of traditional products that are prone to aging and failure.

[0047] 2. Strong environmental adaptability: The unique cross-linked network structure and stabilizer molecular anchoring technology effectively inhibit component migration and phase separation, ensuring that the release film maintains stable release force and surface properties in high temperature and high humidity environments.

[0048] 3. High functional integration: Taking into account high light transmittance and long-lasting antistatic properties, it breaks through the technical bottleneck of the mutual restriction of light transmittance and conductivity of traditional materials, and meets the multiple performance requirements of precision optical devices for protective films. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1 The present invention provides a synthetic route for the stabilizer. DETAILED DESCRIPTION

[0050] The following will clearly and completely describe the technical solution of the present invention in conjunction with the accompanying drawings. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0051] Preparation Example 1

[0052] Synthesis of stabilizer 1:

[0053]

[0054] In the first step, under a nitrogen atmosphere, 200 g of dimethyl sulfoxide, 20 g of starting material 1, 55.95 g of starting material 2, 1.03 g of CuI, 0.15 g of pyridine-2-carboxylic acid, and 57.83 g of potassium phosphate trihydrate were added to the reaction system and heated with stirring at 85°C for 16 hours. After cooling, the resulting reaction mixture was extracted with aqueous ammonia and methyl tert-butyl ether. The organic phase was washed five times with water and twice with saturated NaCl solution. Finally, the combined organic phases were dried over anhydrous Na2SO4 and concentrated to a solid. The solid was purified on a silica gel column using a mixed solution of petroleum ether / ethyl acetate as the eluent, concentrated, and dried to obtain 43.14 g of intermediate 1. MS [MS+1]: 533.

[0055] Step 2: Under a nitrogen atmosphere, 43.14 g of intermediate 1, 450 g of dichloromethane, and 21.60 g of AlCl₃ were added to the reaction system. After stirring, 75 ml of a dichloromethane solution containing 7.63 g of raw material 2 was slowly added dropwise (starting at -20°C, with the temperature not exceeding 0°C during the addition). The reaction was allowed to react at room temperature until complete. Subsequently, the reaction system temperature was lowered to 0°C, and the pH was adjusted to neutral with 0.1 mol / L HCl. After stirring for 30 minutes, the mixture was allowed to stand and separate, retaining the organic phase. The aqueous phase was washed 2-3 times with 50 ml of dichloromethane. The organic phases were combined, dried over anhydrous magnesium sulfate, filtered, and rotary evaporated to obtain a solid. Purification was performed on a silica gel column using a mixed solution of petroleum ether / ethyl acetate as the eluent, followed by concentration and drying to obtain 33.43 g of intermediate 2. MS[MS+1]: 575.

[0056] In the third step, 33.43 g of intermediate 2, 7.16 g of hydroxylamine hydrochloride, 6.06 g of sodium acetate, and 350 g of tetrahydrofuran were added to the reaction system under a nitrogen atmosphere, followed by heating and stirring at 100°C for 12 hours. Afterwards, 1000 ml of water was added to the reaction solution at 0°C, stirred overnight, and then filtered to obtain a powdered solid. The powdered solid was dissolved in 100 ml of ethyl acetate, dried by adding 20 g of anhydrous magnesium sulfate, filtered, and then rotary evaporated to obtain a solid. Purification was performed using a silica gel column with a mixed solution of petroleum ether / ethyl acetate as the eluent, and finally concentrated and dried to obtain 27.50 g of stabilizer 1. MS [MS+1]: 590.

[0057] Stabilizer 1 1 HNMR (deuterated chloroform): δ8.17 (s, 1H), 8.05-8.00 (m, 1H), 7.70-7.64 (m, 1H), 7.56 (s, 1H), 7.45-7.40 (m, 1H), 7.39-7.31 (m, 2H), 7.17-7.16 (m, 1H), 6.98 (dd, 1H), 6.90 (dd, 2H), 4.28 (dq, 4H), 3.23 (s, 2H), 2.45 (s, 3H), 1.27 (t, 6H), 0.06 (t, 9H).

[0058] Preparation Example 2-Preparation Example 8

[0059] The stabilizers synthesized in Preparation Examples 2 to 8 were prepared according to the synthesis method of Preparation Example 1, except that the raw material 3 was replaced. The rest of the preparation was the same as in Preparation Example 1. The specific structure of the raw material 3, the structure of the stabilizer, and the MS [MS+1] data are shown in the table below.

[0060]

[0061]

[0062]

[0063] Example 1

[0064] A preparation method of a single-sided release film comprises the following steps:

[0065] S1. The release agent (polybutyl acrylate, 20 parts), the stabilizer (synthesized in Preparation Example 1, 5 parts), the crosslinking agent (γ-glycidyloxypropyltrimethoxysilane, 3 parts) and the dispersant (sodium dodecylbenzenesulfonate, 1 part) were added to an organic solvent (toluene, 30 parts) and mixed to form a release fluid;

[0066] S2. The release liquid is coated on one side of the base film material (polyimide, 100 parts, thickness of 100 μm) (using a micro-gravure coating process, a coating speed controlled at 10 m / min, a wet film thickness of 50 μm) to form a wet film;

[0067] S3. Staged curing: pre-curing at 80°C for 5 min, followed by final curing at 150°C (at a rate of 5°C / min from 80°C to 150°C) for 25 min.

[0068] S4. The S3 is aged and placed at 25-40 ° C for 12-48 hours, and then the surface is corona treated (the treatment power is 50-300W min / m 2 , so that its surface tension reaches 38-45mN / m) and the finished product is obtained.

[0069] Example 2-Example 8

[0070] A single-sided release film was prepared by referring to the preparation of a single-sided release film described in Example 1, except that the stabilizer was replaced with the stabilizer synthesized in Preparation Examples 2 to 8 in sequence, and the rest remained the same as in Example 1.

[0071] Comparative Example 1

[0072] A single-sided release film was prepared by referring to the preparation of a single-sided release film described in Example 1, except that the stabilizer was replaced with comparative compound 1 in sequence, and the rest remained the same as in Example 1.

[0073] The structure of the comparative compound 1 is:

[0074] Comparative Example 2

[0075] A single-sided release film was prepared by referring to the preparation of a single-sided release film described in Example 1, except that the stabilizer was replaced with the comparative compound 2 in sequence, and the rest remained the same as in Example 1.

[0076] The structure of the comparative compound 2 is:

[0077] Comparative Example 3

[0078] A single-sided release film was prepared by referring to the preparation of a single-sided release film described in Example 1, except that the stabilizer was not added, and the rest remained the same as in Example 1.

[0079] Performance testing:

[0080] Surface Impedance The antistatic properties of the single-sided release films prepared in the examples and comparative examples were tested using a surface impedance tester SRM-110 according to ASTM-D257. The data are shown in the table below.

[0081] sample First surface resistance (Ω) Surface resistance after 200 days (Ω) Example 1 <![CDATA[8.3×10 8 ]]> <![CDATA[9.1×10 8 <!-- 8 -->]]> Example 2 <![CDATA[7.9×10 8 ]]> <![CDATA[8.7×10 8 ]]> Example 3 <![CDATA[6.2×10 8 ]]> <![CDATA[6.8×10 8 ]]> Example 4 <![CDATA[5.4×10 8 ]]> <![CDATA[5.9×10 8 ]]> Example 5 <![CDATA[7.1×10 8 ]]> <![CDATA[7.5×10 8 ]]> Example 6 <![CDATA[4.8×10 8 ]]> <![CDATA[5.2×10 8 ]]> Example 7 <![CDATA[3.6×10 8 ]]> <![CDATA[4.1×10 8 ]]> Example 8 <![CDATA[2.7×10 8 ]]> <![CDATA[2.9×10 8 ]]> Comparative Example 1 <![CDATA[1.5×10 9 ]]> <![CDATA[6.3×10 10 ]]> Comparative Example 2 <![CDATA[2.8×10 9 ]]> <![CDATA[9.8×10 10 ]]> Comparative Example 3 <![CDATA[5.6×10 12 ]]> <![CDATA[2.3×10 13 ]]>

[0082] Performance tests of a single-sided release film described in an embodiment of the present invention and a comparative example show that the embodiment containing deuterated groups performs best, while the comparative example shows exponential degradation in impedance. Fully deuterated phenyl + CD3 has the lowest impedance value and the best stability. The more complete the conjugated system of the stabilizer molecule, the better the effect. The surface impedance of the antistatic coating of a single-sided release film in the embodiment showed almost no change after 200 days, while the surface impedance of the comparative example increased after 200 days.

[0083] While 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 these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A single-sided release film, characterized in that: The following components are included by weight: 100 parts of base film material, 5-20 parts of release agent, 1-10 parts of stabilizer, 0.5-5 parts of cross-linking agent, and 0.1-2 parts of dispersant; The structure of the stabilizer is as shown in Formula 1: R1 is selected from the group consisting of phenyl, furyl, thienyl, methyl, ethyl, tert-butyl, deuterated phenyl, deuterated tert-butyl, and deuterated methyl; Or the R1 is selected from: phenyl, furyl, thienyl substituted by methyl, ethyl, tert-butyl, deuterated tert-butyl, deuterated methyl.

2. A single-sided release film according to claim 1, characterized in that: The stabilizer is selected from any one of the compounds shown in the following structures: The D represents deuterium.

3. The single-sided release film according to claim 1, characterized in that: The base film material is selected from at least one of polyimide, polyethylene terephthalate or polyethylene naphthalate, and has a thickness of 25-125 μm.

4. The single-sided release film according to claim 1, characterized in that: The release agent is selected from at least one of silicone resin, fluorocarbon resin and acrylate resin; The organosilicon resin is polydimethylsiloxane; The fluorocarbon resin is perfluoropolyether or tetrafluoroethylene-hexafluoropropylene copolymer; The acrylic resin is polymethyl methacrylate or polybutyl acrylate.

5. The single-sided release film according to claim 1, characterized in that: The cross-linking agent is at least one of a polyisocyanate compound, an epoxy compound or a silane coupling agent; The polyisocyanate compound is selected from at least one of hexamethylene diisocyanate, isophorone diisocyanate, and toluene diisocyanate; The epoxy compound is bisphenol A epoxy resin or alicyclic epoxy resin; The silane coupling agent is gamma-glycidyloxypropyltrimethoxysilane or methyltrimethoxysilane.

6. The single-sided release film according to claim 1, characterized in that: The dispersant is at least one of a phosphate surfactant or an anionic dispersant; The phosphate surfactant is alkylphenol polyoxyethylene ether phosphate or fatty alcohol polyoxyethylene ether phosphate; The anionic dispersant is sodium dodecylbenzenesulfonate or sodium polyacrylate.

7. A method for preparing a single-sided release film according to any one of claims 1 to 6, characterized in that: The following steps are involved: S1. The release agent, stabilizer, crosslinker and dispersant are added to an organic solvent and mixed to form a release fluid; S2. Coating the release liquid on one side of the base film material to form a wet film; S3. Staged curing: pre-curing at 50-80°C for 1-5 minutes, and then final curing at 100-150°C for 10-25 minutes. S4. The S3 is subjected to aging treatment, and is allowed to stand at 25-40°C for 12-48 hours, and then the surface is subjected to corona treatment to obtain the finished product.

8. The method for preparing a single-sided release film according to claim 7, wherein: The coating described in S2 adopts a micro-gravure coating process, the coating speed is controlled to be 5-20 m / min, and the wet film thickness is 5-50 μm.

9. The method for preparing a single-sided release film according to claim 7, wherein: The final curing stage in S3 adopts a gradient temperature increase mode, increasing the temperature from 80°C to 150°C at a rate of 2-5°C / min.

10. The method for preparing a single-sided release film according to claim 7, wherein: The surface is corona treated with a treatment power of 50-300W·min / m 2 , so that its surface tension reaches 38-45mN / m.

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