Organosilicon release composition, organosilicon release film and preparation method

Abstract

This invention discloses an organosilicon release composition, an organosilicon release film, and a preparation method thereof. The organosilicon release composition comprises, by weight, 93-98 parts of an ultra-low peeling agent, 0.5-1.2 parts of a hydrogen-containing polysiloxane crosslinking agent, 0.5-1.2 parts of a first crosslinking aid, 1-2 parts of a second crosslinking aid, 1-3 parts of a platinum catalyst, and an appropriate amount of organic solvent. The solid content of the composition is 2.5%-3.5%. The ultra-low peeling agent is at least one of vinyl-terminated polydiorganosiloxane, vinyl-terminated methyl / phenyl copolymer siloxane oligomer, and vinyl-terminated methyl / long-chain alkyl copolymer siloxane oligomer. The first crosslinking aid is a polysiloxane oligomer containing silane-hydrogen bonds, and the second crosslinking aid is a polysiloxane oligomer containing alkenyl functional groups. This invention optimizes the crosslinking network structure by using a compound system of silane-hydrogen bond-containing and alkenyl functional group-containing dual crosslinking aids. This allows the release film to maintain excellent initial release performance while effectively inhibiting the growth of peel force during storage and improving its storage stability.

Description

Technical Field

[0001] This invention belongs to the field of release film technology, specifically relating to an organosilicon release composition, an organosilicon release film, and a preparation method thereof. Background Technology

[0002] Silicone release films are widely used in various acrylic pressure-sensitive adhesive applications due to their excellent release properties, good coating compatibility, and temperature resistance, such as die-cut protective films, OCA optical adhesives, electronic tapes, and medical dressings. In practical use, silicone release films are typically laminated with acrylic adhesive layers, wound up, stored, and then peeled off after a certain period of time.

[0003] However, after being laminated and wound with an acrylic adhesive layer, traditional solvent-based silicone release films generally exhibit a significant increase in peel strength after long-term storage or exposure to high temperature and humidity environments. Specifically, the peel strength of traditional solvent-based silicone release films generally increases by more than 30% after long-term storage. Summary of the Invention

[0004] The purpose of this invention is to provide an organosilicon release composition, an organosilicon release film, and a preparation method. By designing the proportions of the components in the organosilicon release composition, the release film maintains excellent initial release performance while effectively suppressing the growth of peeling force during storage, thereby improving its storage stability.

[0005] To achieve the above objectives, a specific embodiment of the present invention provides the following technical solution: an organosilicon release composition, comprising, by mass parts, the following raw material components: 93-98 parts of an ultra-low peeling agent, 0.5-1.2 parts of a hydrogen-containing polysiloxane crosslinking agent, 0.5-1.2 parts of a first crosslinking aid, 1-2 parts of a second crosslinking aid, 1-3 parts of a platinum catalyst, and an appropriate amount of organic solvent; the solid content of the organosilicon release composition is 2.5%-3.5%; the ultra-low peeling agent is at least one of vinyl-terminated polydiorganosilicon, vinyl-terminated methyl / phenyl copolymer siloxane oligomer, and vinyl-terminated methyl / long-chain alkyl copolymer siloxane oligomer; the first crosslinking aid is a polysiloxane oligomer containing silane-hydrogen bonds, and the second crosslinking aid is a polysiloxane oligomer containing alkenyl functional groups.

[0006] In one or more embodiments of the present invention, the first crosslinking aid is at least one of hydrogen-containing polymethylsiloxane oligomer, end-hydrogen-containing polydimethylsiloxane oligomer, and side-hydrogen-containing polydimethylsiloxane oligomer; the second crosslinking aid is at least one of vinyl-terminated polydimethylsiloxane oligomer, side-vinyl polydimethylsiloxane oligomer, and end-allyl polydimethylsiloxane oligomer.

[0007] In one or more embodiments of the present invention, the hydrogen-containing polysiloxane crosslinking agent is at least one of methylhydrosiloxane-dimethylsiloxane copolymer, high hydrogen content polymethylhydrosiloxane, and hydrogen-containing methyl / phenyl copolysiloxane.

[0008] In one or more embodiments of the present invention, the raw material component further includes 2 to 7 parts by weight of a non-migratory release force modifier, wherein the non-migratory release force modifier is at least one of terminal vinyl polydimethylsiloxane oligomer, side-chain vinyl-modified polydimethylsiloxane oligomer, and multifunctional vinyl polysiloxane oligomer.

[0009] In one or more embodiments of the present invention, the platinum catalyst is at least one of platinum-vinylsiloxane complex, platinum-olefin complex, and platinum-cyclopentadienyl complex.

[0010] In one or more embodiments of the present invention, the organic solvent is at least one of aromatic hydrocarbons, ketones and C1-C4 aliphatic alcohols.

[0011] A specific embodiment of the present invention also provides an organosilicon release film, including a substrate and an organosilicon release coating disposed on the surface of the substrate; the organosilicon release coating is formed by curing the above-mentioned organosilicon release composition.

[0012] In one or more embodiments of the present invention, the substrate is any one of PET, PI, PEN, PP, and PE, and the thickness of the substrate is 38μm to 100μm.

[0013] A specific embodiment of the present invention also provides a method for preparing an organosilicon release film, comprising the following steps:

[0014] The substrate is subjected to corona treatment;

[0015] After diluting and mixing the ultra-low peeling agent with an organic solvent, the first crosslinking aid, the second crosslinking aid, the platinum catalyst, and the hydrogen-containing polysiloxane crosslinking agent are added in sequence to obtain an organosilicon release composition.

[0016] The organosilicon release composition is coated onto the surface of a substrate after corona treatment, and after heating and curing, an organosilicon release coating is formed on the surface of the substrate to obtain the organosilicon release film.

[0017] When the raw material components of the organosilicon release composition include a non-migratory release force modifier, the non-migratory release force modifier is blended and diluted with the ultra-low peeling agent.

[0018] In one or more embodiments of the present invention, the curing temperature is 120℃~150℃ and the curing time is 2min~3min.

[0019] Compared with existing technologies, this invention achieves superior performance by precisely compounding and synergistically controlling the components of the silicone release composition. It utilizes a hydrogen-containing polysiloxane crosslinking agent combined with a vinyl-terminated ultra-low peeling agent. Under the action of a platinum catalyst, the two undergo a hydrosilylation reaction, constructing a densely packed, rigid three-dimensional crosslinked network framework. This locks the initial peeling force of the silicone release film coating on the acrylic pressure-sensitive adhesive within an ultra-light peeling range of 2-5 gf / 25 mm, ensuring excellent ultra-low peeling characteristics. Simultaneously, a dual crosslinking aid system is introduced. The first crosslinking aid, containing silane-hydrogen bonds, provides active Si-H sites, replenishing residual unsaturated sites after crosslinking of the main agent and repairing microscopic pore defects within the crosslinked network. The second crosslinking aid, containing alkenyl functional groups, can undergo a grafting and end-capping reaction with residual silane-hydrogen bonds in the system, passivating residual active groups and inhibiting post-crosslinking and continuous precipitation of small-molecule siloxanes. The two work synergistically to greatly improve the density of the cross-linked network, seal the micro-pores inside the coating, effectively inhibit the migration of low molecular weight silicon species and the penetration of external moisture and impurities, overcome the defect that the peel force increase in existing technologies generally exceeds 30%, and make the peel force increase rate of the release film less than 15% after long-term storage at room temperature, high-temperature aging and humid heat aging, thus achieving the peel force stability of the release film during long-term storage.

[0020] After corona activation treatment, a large number of polar groups are formed on the surface of the PET substrate, significantly increasing the surface tension, which is beneficial for the uniform spreading and wetting of the silicone release composition. During the subsequent heat curing process, the active silane bonds in the hydrogen-containing polysiloxane crosslinking agent may interact chemically with the polar groups on the substrate surface to a certain extent. At the same time, the micro-rough structure formed by corona treatment also provides effective physical anchoring points for the coating. The synergistic effect of these two factors significantly enhances the adhesion between the coating and the substrate, effectively overcoming the defects of coating floating on the surface and easily falling off in existing ultra-low peeling systems.

[0021] Furthermore, the non-migratory release force modifier added in this invention can effectively regulate the molecular arrangement of ultra-low peeling agent, improve the resin agglomeration and surface energy unevenness under low solid content and thin coating conditions, make the overall surface energy of the coating highly uniform and the peeling performance consistent, and ensure that the ultra-light peeling force window (2~5gf / 25mm) determined by the agent does not drift or disperse in actual coating, thereby further improving the stability of the ultra-light peeling performance of the release film. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This is a schematic flowchart of a method for preparing an organosilicon release film according to an embodiment of the present invention. Detailed Implementation

[0024] To enable those skilled in the art to better understand the technical solutions in this disclosure, the technical solutions in the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this disclosure, and not all embodiments. Based on the embodiments in this disclosure, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this disclosure.

[0025] The inventors discovered through research that the main reasons for the significant increase in peel strength of traditional solvent-based silicone release films after lamination and winding with acrylic adhesive layers, and after long-term storage or exposure to high temperature and humidity environments, include the following three aspects:

[0026] (1) Secondary crosslinking effect: The crosslinking reaction of the organosilicon coating is incomplete during the curing process, and the active silicon functional groups, such as silanol and vinyl groups, remain in the coating. During storage, slow secondary crosslinking occurs over time, resulting in a decrease in the surface energy of the release layer and an increase in the interfacial adhesion.

[0027] (2) Low molecular weight migration effect: Low molecular weight cyclosiloxanes that do not participate in the cross-linking reaction in the organosilicon system migrate to the interface between the silicone coating and the adhesive layer during storage, gradually enhancing the interfacial bonding force between the organosilicon and the acrylic adhesive, thereby increasing the peel strength.

[0028] (3) Water vapor erosion effect: Water vapor in the external environment can penetrate into the interior of the film through the micropores of the organosilicon coating, destroying the original dense structure of the coating, weakening its anti-migration and anti-adhesion stability, and further aggravating the growth of peel force.

[0029] Due to the combined effects of the above factors, the peel strength of traditional solvent-based silicone release films generally increases by more than 30% after long-term storage. In extreme cases, serious defects may occur, such as difficulty in peeling off the acrylic adhesive layer, residual adhesive, and silicone oil transfer to the adhesive surface, which cannot meet the quality requirements of high-end adhesive products for long-term storage stability and complex usage environments.

[0030] To address the aforementioned issue of increased peel force, related technologies often employ methods such as modifying a single main agent or compounding conventional modifiers to prepare silicone release films, or improving the aging stability of the release film by increasing the amount of crosslinking agent. However, these methods still have the following significant shortcomings: their control over the increase in peel force is limited, making it difficult to balance initial release force and storage stability, often resulting in excessive deviation of the initial release force; some modification schemes have poor compatibility with existing solvent-based coating lines and curing processes, requiring significant adjustments to equipment or process parameters, increasing the cost of technological upgrades and production risks for enterprises; and the method of improving the aging stability of the release film by increasing the amount of crosslinking agent often leads to a significant increase in initial peel force, making it difficult to simultaneously meet the dual requirements of ultra-light release and long-term storage stability.

[0031] Therefore, the present invention provides an organosilicon release composition, an organosilicon release film, and a preparation method, which can effectively suppress the growth of peel force during storage while maintaining excellent initial release performance, and is well compatible with existing production lines.

[0032] The organosilicon release composition of one embodiment of the present invention comprises, by weight, the following raw material components: 93-98 parts of an ultra-low peeling agent, 0.5-1.2 parts of a hydrogen-containing polysiloxane crosslinking agent, 0.5-1.2 parts of a first crosslinking aid, 1-2 parts of a second crosslinking aid, 1-3 parts of a platinum catalyst, and an appropriate amount of organic solvent; the solid content of the organosilicon release composition is 2.5%-3.5%; the ultra-low peeling agent is at least one of vinyl-terminated polydiorganosilicon, vinyl-terminated methyl / phenyl copolymer siloxane oligomer, and vinyl-terminated methyl / long-chain alkyl copolymer siloxane oligomer; the first crosslinking aid is a polysiloxane oligomer containing silane-hydrogen bonds, and the second crosslinking aid is a polysiloxane oligomer containing alkenyl functional groups.

[0033] The ultra-low peel strength agent, with its long-chain polydimethylsiloxane and end-capped vinyl groups, is the core component for constructing the main network of the release coating. After curing, the coating surface exhibits high silicon enrichment, achieving the fundamental properties of ultra-low peel strength and low residual adhesive content. The ultra-low peel strength agent can be a commercially available addition-type silicone release agent, such as Dow SYL-OFF™ SB9186, Shin-Etsu KS-847 and KS-858H, Momentive RSN-6017 and UV-7400, with SYL-OFF™ SB9186 being preferred. After platinum-catalyzed curing, this agent can stably control the initial peel force of the silicone release coating on the acrylic pressure-sensitive adhesive within the ultra-light peel range of 2~5 gf / 25 mm, effectively avoiding problems of high peel force or unstable peeling.

[0034] The hydrogen-containing polysiloxane crosslinking agent is rich in active silicon-hydrogen bonds (Si-H). Under the action of a platinum catalyst, it irreversibly undergoes a hydrosilylation reaction with the vinyl groups in the main agent, thereby constructing a high-density three-dimensional crosslinking network to suppress the free precipitation of low-molecular-weight silicone oil, making the internal structure of the coating dense and stable.

[0035] In a preferred embodiment, the hydrogen-containing polysiloxane crosslinking agent is selected from at least one of methylhydrosiloxane-dimethylsiloxane copolymer, high-hydrogen-content polymethylhydrosiloxane, and hydrogen-containing methyl / phenyl copolysiloxane. Specifically, the hydrogen-containing polysiloxane crosslinking agent can be at least one of Dow SYL-OFF™ 7689, Shin-Etsu KF-99 (hydrogen-containing silicone oil, hydrogen mass fraction 0.5~1.6 wt%), Momentive TSF-484 / TSF-486 (hydrogen-containing polymethylsiloxane oligomer), and Wacker Crosslinker V series, with SYL-OFF™ 7689 being more preferred.

[0036] This invention introduces a dual crosslinking aid system. The first crosslinking aid, containing silane-hydrogen bonds, provides active Si-H sites, replenishing residual unsaturated sites after crosslinking of the main agent and repairing microscopic pore defects within the crosslinking network. The second crosslinking aid, containing alkenyl functional groups, can undergo a grafting and end-capping reaction with residual silane-hydrogen bonds in the system, passivating residual active groups and inhibiting post-crosslinking and continuous precipitation of small-molecule siloxanes. The synergistic effect of these two aids greatly improves the density of the crosslinking network, seals the microscopic pores within the coating, effectively inhibits the migration of low-molecular-weight silicon species and the penetration of external moisture and impurities, overcoming the defect in existing technologies where the peel force increase generally exceeds 30%. This ensures that the peel force increase rate of the release film after long-term storage at room temperature, high-temperature aging, and humid aging is all less than 15%, achieving peel force stability of the release film during long-term storage.

[0037] In the aforementioned dense solid network structure, unreacted low molecular weight siloxanes are tightly confined within the tiny meshes of the cross-linked network. This utilizes a dual mechanism of physical blocking and chemical cross-linking to significantly reduce the risk of low molecular weight organosilicon precipitation without sacrificing the coating's flexibility.

[0038] In a preferred embodiment, the first crosslinking aid is at least one of hydrogen-containing polymethylsiloxane oligomers, hydrogen-terminated polydimethylsiloxane oligomers, and side-containing polydimethylsiloxane oligomers; the second crosslinking aid is at least one of vinyl-terminated polydimethylsiloxane oligomers, side-vinyl polydimethylsiloxane oligomers, and allyl-terminated polydimethylsiloxane oligomers. Specifically, the first crosslinking aid can be at least one of LTC 200A, Shin-Etsu KF-9901, and Momentive TSF-4701, and the second crosslinking aid can be at least one of LTC 200B, Shin-Etsu X-22-163, and Dow DOWSIL™ BY-16-752.

[0039] It is important to note that silane-hydrogen bond-containing agents and alkenyl functional group-containing agents are typically used to temporarily adjust the crosslinking density of addition-type liquid silicone rubber or encapsulating adhesive systems. However, in solvent-based addition-type systems, their coexistence with platinum catalysts readily induces silane-hydrogen pre-crosslinking at room temperature, leading to gelation of the coating solution. Therefore, those skilled in the art generally avoid introducing both simultaneously into addition-type release systems containing platinum catalysts to adjust the crosslinking density. This invention not only achieves physical sealing of the micro-mesh in the crosslinking network by having both coexist in the organosilicon release composition, but also strictly limits the addition amounts of the two types of crosslinking agents to match the Si-H to vinyl molar ratio, reducing the driving force of the reaction at room temperature. Furthermore, by controlling the overall solid content to 2.5%~3.5%, it effectively reduces the reactant concentration and decreases the risk of silane-hydrogen pre-crosslinking at room temperature. Thus, while ensuring the storage stability of the coating solution, it fully leverages the synergistic densification effect of the dual crosslinking agents on the crosslinking network.

[0040] In a preferred embodiment, the raw material component further includes 2-7 parts by weight of a non-migratory release force modifier, wherein the non-migratory release force modifier is at least one of terminal vinyl polydimethylsiloxane oligomer, side-chain vinyl-modified polydimethylsiloxane oligomer, and multifunctional vinyl polysiloxane oligomer. Specifically, the non-migratory release force modifier may be at least one of SYL-OFF™ 7210, Shin-Etsu KS-777, and Momentive RCA-711.

[0041] The addition of non-migrating release force modifiers to silicone release compositions can effectively regulate the molecular arrangement of ultra-low peeling agents, improve resin agglomeration and uneven surface energy under low solid content and thin coating conditions, effectively improve film-forming defects such as pinholes and orange peel, and its large molecular weight and good compatibility with cross-linking networks make it difficult to migrate to the pressure-sensitive adhesive layer, resulting in highly uniform overall surface energy of the coating and strong consistency in peel performance. This ensures that the ultra-light peel force window (2~5gf / 25mm) determined by the main agent does not drift or disperse in actual coating, thereby further improving the stability of the ultra-light peel performance of the release film.

[0042] The platinum catalyst acts as a reaction switch, precisely catalyzing the hydrosilylation reaction to ensure the organosilicon release composition cures quickly, avoiding performance collapse due to incomplete curing. To further alleviate the pre-crosslinking phenomenon of hydrosilylation in hydroxyl-containing and alkenyl-containing auxiliaries, this invention preferably uses a thermally triggered platinum catalyst with weak room-temperature catalytic activity, which fully activates crosslinking only at a curing temperature of 120°C to 150°C. It should be noted that the platinum catalyst in this invention is added in the form of a platinum catalyst stock solution.

[0043] In a preferred embodiment, the platinum catalyst is at least one of a platinum-vinylsiloxane complex, a platinum-olefin complex, and a platinum-cyclopentadienyl complex. Specifically, the platinum catalyst can be at least one of SYL-OFF™ 4000, Momentive PC-072, and Wacker CAT-PT 2.

[0044] Optionally, the silicone release composition may also contain 0.001 to 0.05 parts by weight of an alkynyl alcohol inhibitor, which is added before the platinum catalyst to further improve the room temperature storage stability of the coating solution.

[0045] Organic solvents are used to dilute the components of the organosilicon release composition and adjust its solid content to the range of 2.5% to 3.5%. It should be noted that the organic solvents used in this invention pose no risk of poisoning the platinum catalyst.

[0046] In a preferred embodiment, the organic solvent is at least one selected from aromatic hydrocarbons, ketones, and C1-C4 aliphatic alcohols. Specifically, the organic solvent may be at least one selected from toluene, isopropanol, and methyl isobutyl ketone.

[0047] A specific embodiment of the present invention also provides an organosilicon release film, comprising a substrate and an organosilicon release coating disposed on the surface of the substrate; the organosilicon release coating is formed by curing the above-mentioned organosilicon release composition.

[0048] Specifically, the substrate is any one of PET, PI, PEN, PP, and PE, and the thickness of the substrate is 38μm to 100μm. Preferably, the substrate is PET. After corona activation treatment, a large number of polar groups are formed on the surface of the PET substrate, and the surface tension is significantly increased, which is beneficial to the uniform spreading and wetting of the organosilicon release composition. During the heating and curing process, the active silane bonds in the hydrogen-containing polysiloxane crosslinking agent can form chemical interactions with the polar groups on the substrate surface. Combined with the micro-rough structure generated by corona treatment, physical anchoring is achieved. The two work together to enhance the interfacial bonding force between the coating and the substrate, forming a stable molecular-level anchoring structure, effectively overcoming the defects of the coating floating on the surface and easily falling off in the existing ultra-low peeling system.

[0049] A specific embodiment of the present invention also provides a method for preparing an organosilicon release film, such as... Figure 1 As shown, the preparation method includes the following steps:

[0050] S1. Perform corona treatment on the substrate.

[0051] In this process, the substrate is subjected to corona treatment to control the surface tension of the substrate at 38~42dyn, thereby improving the adhesion of the silicone release composition to the substrate surface.

[0052] S2. After diluting and mixing the ultra-low peeling agent with an organic solvent, add the first crosslinking aid, the second crosslinking aid, the platinum catalyst, and the hydrogen-containing polysiloxane crosslinking agent in sequence to obtain the organosilicon release composition.

[0053] Specifically, after mixing the ultra-low release agent and organic solvent, the first crosslinking aid, the second crosslinking aid, the platinum catalyst, and the hydrogen-containing polysiloxane crosslinking agent are added sequentially to obtain the silicone release composition. The order of addition is strictly controlled to prevent premature crosslinking in certain areas, which would affect the properties of the final silicone release coating. The amount of organic solvent used should be controlled to maintain the solid content of the silicone release composition between 2.5% and 3.5%.

[0054] It should be noted that when the raw material components of the organosilicon release composition include a non-migratory release force modifier, the non-migratory release force modifier in step S2 is blended and diluted with the ultra-low peeling agent.

[0055] S3. The silicone release composition is coated on the surface of the substrate after corona treatment, and after heating and curing, a silicone release coating is formed on the surface of the substrate to obtain the silicone release film.

[0056] In this process, the prepared silicone release composition is uniformly coated onto the corona-treated substrate surface using a coating rod. The curing temperature is 120℃~150℃, and the curing time is 2min~3min. The use of a thermally triggered platinum catalyst can further alleviate the phenomenon of hydrogen silane pre-crosslinking of the first and second crosslinking aids at room temperature, while ensuring that the silicone release composition is fully crosslinked and cured.

[0057] The organosilicon release composition, organosilicon release film, and preparation method of the present invention will be described in detail below with reference to specific embodiments and comparative examples.

[0058] Example 1

[0059] A 50μm PET base film was selected and subjected to corona treatment.

[0060] 95 parts by weight of SYL-OFF™ SB9186 were diluted with a mixed solvent of toluene, isopropanol, and MIBK (mass ratio 60:25:15); after thorough mixing, 0.5 parts of LTC 200A, 1 part of LTC 200B, 1 part of Syl-Off™ 4000, and 0.5 parts of SYL-OFF™ 7689 were added to obtain a silicone release composition with a solid content of 3%.

[0061] The prepared silicone release composition was uniformly coated onto the corona-treated PET substrate film surface using a coating liner, and then cured by heating at 120°C for 2 minutes to obtain the silicone release film of this invention. The dry film coating weight of the silicone release coating was 0.2 g / m². 2 .

[0062] Example 2

[0063] A 50μm PET base film was selected and subjected to corona treatment.

[0064] By weight, 95 parts of SYL-OFF™ SB9186 and 5 parts of SYL-OFF™ 7210 were diluted with a mixed solvent of toluene, isopropanol, and MIBK (mass ratio 60:25:15); after thorough mixing, 0.5 parts of LTC 200A, 1 part of LTC 200B, 1 part of Syl-Off™ 4000, and 0.5 parts of SYL-OFF™ 7689 were added to obtain a silicone release composition with a solid content of 3%.

[0065] The prepared silicone release composition was uniformly coated onto the corona-treated PET substrate film surface using a coating liner, and then cured by heating at 120°C for 2 minutes to obtain the silicone release film of this invention. The dry film coating weight of the silicone release coating was 0.2 g / m². 2 .

[0066] Example 3

[0067] A 50μm PET base film was selected and subjected to corona treatment.

[0068] By weight, 97 parts of SYL-OFF™ SB9186 and 3 parts of SYL-OFF™ 7210 were diluted with a mixed solvent of toluene, isopropanol, and MIBK (mass ratio 60:25:15); after thorough mixing, 1.2 parts of LTC 200A, 2 parts of LTC 200B, 3 parts of Syl-Off™ 4000, and 1.2 parts of SYL-OFF™ 7689 were added to obtain a silicone release composition with a solid content of 3%.

[0069] The prepared silicone release composition was uniformly coated onto the corona-treated PET substrate film surface using a coating liner, and then cured by heating at 120°C for 2 minutes to obtain the silicone release film of this invention. The dry film coating weight of the silicone release coating was 0.2 g / m². 2 .

[0070] Example 4

[0071] A 50μm PET base film was selected and subjected to corona treatment.

[0072] By weight, 98 parts of SYL-OFF™ SB9186 and 2 parts of SYL-OFF™ 7210 were diluted with a mixed solvent of toluene, isopropanol, and MIBK (mass ratio 60:25:15); after thorough mixing, 0.8 parts of LTC 200A, 1.5 parts of LTC 200B, 2 parts of Syl-Off™ 4000, and 0.8 parts of SYL-OFF™ 7689 were added to obtain a silicone release composition with a solid content of 2.5%.

[0073] The prepared silicone release composition was uniformly coated onto the corona-treated PET substrate film surface using a coating liner, and then cured by heating at 130°C for 2 minutes to obtain the silicone release film of this invention. The dry film coating weight of the silicone release coating was 0.15 g / m². 2 .

[0074] Example 5

[0075] A 50μm PET base film was selected and subjected to corona treatment.

[0076] By weight, 93 parts of SYL-OFF™ SB9186 and 7 parts of SYL-OFF™ 7210 were diluted with a mixed solvent of toluene, isopropanol, and MIBK (mass ratio 60:25:15); after thorough mixing, 1 part of LTC 200A, 1.8 parts of LTC 200B, 2.5 parts of Syl-Off™ 4000, and 1 part of SYL-OFF™ 7689 were added to obtain a silicone release composition with a solid content of 3.5%.

[0077] The prepared silicone release composition was uniformly coated onto the corona-treated PET substrate film surface using a coating liner, and then cured by heating at 140°C for 2.5 minutes to obtain the silicone release film of this invention. The dry film coating weight of the silicone release coating was 0.22 g / m². 2 .

[0078] Comparative Example 1

[0079] A 50μm PET base film was selected and subjected to corona treatment.

[0080] 100 parts by weight of DOWSIL™ LTC 761 were diluted with a mixed solvent of toluene, isopropanol and MIBK (mass ratio 60:25:15); after thorough mixing, 1.5 parts of Syl-Off™ 4000 and 0.8 parts of Syl-Off™ 7672 were added to obtain a silicone release composition with a solid content of 3%.

[0081] The prepared silicone release composition was uniformly coated onto the corona-treated PET substrate film using a coating liner, and then cured by heating at 120℃ for 2 minutes to obtain the silicone release film. The dry film coating weight of the silicone release coating was 0.2 g / m². 2 .

[0082] Comparative Example 2

[0083] A 50μm PET base film was selected and subjected to corona treatment.

[0084] By weight, 97 parts of SYL-OFF SB9186 and 3 parts of SYL-OFF™ 7210 were diluted with a mixed solvent of toluene, isopropanol, and MIBK (mass ratio 60:25:15); after thorough mixing, 2 parts of Syl-Off™ 4000 and 0.5 parts of Syl-Off™ 7689 were added to obtain a silicone release composition with a solid content of 3%.

[0085] The prepared silicone release composition was uniformly coated onto the corona-treated PET substrate film using a coating liner, and then cured by heating at 120℃ for 2 minutes to obtain the silicone release film. The dry film coating weight of the silicone release coating was 0.2 g / m². 2 .

[0086] It should be noted that the relevant technology adopts a high cross-linking stability system scheme, which improves the peel strength stability of the release film during storage by increasing the amount of cross-linking agent. The present invention shows the following comparative example 3 to verify the defect of the traditional technology that "stability and initial peel strength are incompatible".

[0087] Comparative Example 3

[0088] A 50μm PET base film was selected and subjected to corona treatment.

[0089] 100 parts by weight of DOWSIL™ LTC 761 were diluted with a mixed solvent of toluene, isopropanol and MIBK (mass ratio 60:25:15); after thorough mixing, 1.5 parts of Syl-Off™ 4000 and 1.8 parts of Syl-Off™ 7672 were added to obtain a silicone release composition with a solid content of 3%.

[0090] The prepared silicone release composition was uniformly coated onto the corona-treated PET substrate film using a coating liner, and then cured by heating at 120℃ for 2 minutes to obtain the silicone release film. The dry film coating weight of the silicone release coating was 0.2 g / m². 2 .

[0091] Among them, Comparative Example 1 is an organosilicon release film prepared using commercially available general single-component LTC 761 release agent according to its standard ratio; Comparative Example 2 is an organosilicon release film prepared using a conventional modified single regulator system; and Comparative Example 3 is an organosilicon release film prepared using a commercially available high crosslinking stability system.

[0092] The release films prepared in Examples 1-5 and Comparative Examples 1-3 were subjected to the following performance tests:

[0093] (1) Initial peel force (for acrylate OCA adhesive, 25mm sample):

[0094] The test was conducted according to GB / T 2792-2014 standard. The release film was cut into 25mm × 200mm samples, bonded to an acrylic OCA film (50μm thick), and rolled back and forth once with a 2kg rubber roller. After being placed in a standard environment (23±2℃, 50±5% RH) for 20 minutes, a 180° peel test was performed using a universal testing machine at a peel speed of 300mm / min. The peel force value was recorded as gf / 25mm. Each sample was tested 5 times, and the average value was taken.

[0095] (2) Long-term storage at room temperature (25℃, for 90 days):

[0096] The release film sample with OCA adhesive film was placed in a constant temperature and humidity chamber and stored for 90 days at 25±2℃ and 60±5% RH. After removal, it was equilibrated for 2 hours under standard conditions, and the peel force was measured according to the peel force test method described above. The growth rate relative to the initial peel force was calculated.

[0097] (3) High-temperature aging (80℃, 72h):

[0098] The release film sample with the OCA adhesive film was placed in a forced-air drying oven and aged at 80±2℃ for 72 hours. After removal, it was cooled and equilibrated under standard conditions for 2 hours. The peel force was then measured according to the peel force test method described above, and the growth rate relative to the initial peel force was calculated.

[0099] (4) Damp heat aging (85℃, 85% relative humidity, 72h):

[0100] The release film sample with OCA adhesive film was placed in a constant temperature and humidity chamber and aged for 72 hours at 85±2℃ and 85±3% RH. After removal, it was cooled and equilibrated under standard conditions for 2 hours. The peel force was then measured according to the peel force test method described above, and the growth rate relative to the initial peel force was calculated.

[0101] The test results are shown in the table below:

[0102] Table 1. Peel force test results of each embodiment and comparative example.

[0103]

[0104] Based on the test data of Examples 1-5 and Comparative Examples 1-3 in Table 1, it can be seen that:

[0105] The initial peel force of Examples 1 to 5 of the present invention is stably controlled within the ultra-light peel range of 2.8 to 3.5 gf / 25 mm, which can meet the bonding requirements of high-end acrylic adhesive products. The peel force growth rate of all examples after aging at room temperature, high temperature, and humid heat is less than 15%. Among them, the harsh working condition formulation (Example 3) has the best stability, with a growth rate of only 10.32% after aging in humid heat. The low coating amount precision formulation (Example 4) takes into account both thinness and high stability, and is suitable for the differentiated needs of multiple scenarios.

[0106] Comparative Example 1: The commercially available conventional system lacks functional modification and densification agents, resulting in a high initial peel strength. Furthermore, the peel strength increases dramatically by over 35% after aging, exhibiting extremely poor stability under humid and hot conditions, easily leading to problems such as difficulty in peeling and residue. Comparative Example 2: This is a traditional single-modification system. Although the initial peel strength meets the standard, it lacks an aging-resistant dense structure, failing to inhibit low-molecular-weight migration and moisture erosion. Its aging growth rate exceeds 24%, and its stability is far inferior to that of this invention. Comparative Example 3: While high cross-linking improves stability, although the increase is somewhat reduced, it directly leads to a significant increase in initial peel strength, making ultra-light peeling impossible. This confirms the core defect of existing technologies: "incompatibility between initial performance and stability."

[0107] Multiple sets of differentiated embodiments and comparative examples fully demonstrate that the five-element synergistic compounding system of the present invention can accurately balance the initial release performance and the storage stability under all working conditions. Moreover, different ratios and processes can be adapted to diverse application scenarios such as thin and light precision, wide-range mass production, and harsh working conditions, and the process compatibility is extremely strong.

[0108] It is evident that, under the premise of laminating acrylic OCA films with the same formulation, the release films provided in the comparative examples all exhibit high initial peel strength, with peel strength growth rates exceeding 24% after long-term storage at room temperature, high-temperature aging, and humid heat aging. In contrast, the release film provided by this invention maintains an initial peel strength within the ultra-light peel range of 2-5 gf / 25mm, and even under conditions of long-term storage at room temperature, high-temperature aging, and humid heat aging, the peel strength growth rate remains below 15%, maintaining its ultra-light peel strength performance. This demonstrates that, through precise compounding and synergistic control of the components of the organosilicon release composition, this invention can provide a release film that combines excellent initial release performance with long-term storage stability.

[0109] The principle behind achieving the above-mentioned technical effects in this invention lies in the precise compounding and synergistic control of each component of the organosilicon release composition. A hydrogen-containing polysiloxane crosslinking agent is selected in combination with a vinyl-terminated ultra-low peeling agent. Under the action of a platinum catalyst, the two undergo a hydrosilylation reaction, constructing a three-dimensional crosslinked network framework with dense nodes and strong chain segment rigidity. This locks the initial peeling force of the organosilicon release film coating on the acrylic pressure-sensitive adhesive within an ultra-light peeling range of 2~5 gf / 25 mm, ensuring excellent ultra-low peeling characteristics. Simultaneously, a dual crosslinking aid system is introduced. The first crosslinking aid, containing silane-hydrogen bonds, provides active Si-H sites, replenishing the residual unsaturated sites after crosslinking of the main agent and repairing microscopic pore defects within the crosslinked network. The second crosslinking aid, containing alkenyl functional groups, can undergo a grafting and end-capping reaction with the residual silane-hydrogen bonds in the system, passivating the residual active groups and inhibiting post-crosslinking and continuous precipitation of small molecule siloxanes. The two work synergistically to greatly improve the density of the cross-linked network, seal the micro-pores inside the coating, effectively inhibit the migration of low molecular weight silicon species and the penetration of external moisture and impurities, overcome the defect that the peel force increase in existing technologies generally exceeds 30%, and make the peel force increase rate of the release film less than 15% after long-term storage at room temperature, high-temperature aging and humid heat aging, thus achieving the peel force stability of the release film during long-term storage.

[0110] Furthermore, the curing temperature and coating parameters used in this invention are similar to those of traditional low-temperature solvent-based release films, eliminating the need to modify existing production equipment. New and old products can be quickly switched to mass production. The initial shape of the release film maintains an ultra-light peeling effect, and the coating exhibits low migration, no residue, and no silicone transfer. It is suitable for all categories of applications, including acrylic adhesive labels, tapes, and electronic die-cutting, making it widely applicable.

[0111] Additionally, it should be noted that the system of this invention is limited to an addition-type platinum-catalyzed organosilicon system, and the use of condensation-type silicone release agents should be avoided to prevent water vapor-induced hydrolysis and abnormal increases in force. All main materials and additives are selected as sulfur-free, amine-free, and heavy metal-free to prevent platinum catalyst poisoning leading to poor curing. Anhydrous solvents are used to ensure the density and moisture and heat resistance of the silicone coating.

[0112] The release film of this invention can be a special release film for acrylic adhesives, and is preferably matched with various solvent-based acrylic pressure-sensitive adhesive products. For example, it can be used in fields such as self-adhesive labels, double-sided tapes, foam adhesives, and electronic die-cutting accessories. It can meet the requirements of conventional warehousing use and can also be adapted to complex working conditions such as high humidity in the south and high temperature outdoors. Compared with traditional release films, the product's service life and end-use stability are significantly improved.

[0113] It will be apparent to those skilled in the art that this disclosure is not limited to the details of the exemplary embodiments described above, and that this disclosure can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of this disclosure is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within this disclosure. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0114] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. An organosilicon release composition, characterized in that, The composition comprises, by weight parts, the following raw material components: 93-98 parts of ultra-low peeling agent, 0.5-1.2 parts of hydrogen-containing polysiloxane crosslinking agent, 0.5-1.2 parts of first crosslinking aid, 1-2 parts of second crosslinking aid, 1-3 parts of platinum catalyst, and an appropriate amount of organic solvent; the solid content of the organosilicon release composition is 2.5%-3.5%; the ultra-low peeling agent is at least one of vinyl-terminated polydiorganosiloxane, vinyl-terminated methyl / phenyl copolymer siloxane oligomer, and vinyl-terminated methyl / long-chain alkyl copolymer siloxane oligomer; the first crosslinking aid is a polysiloxane oligomer containing silane-hydrogen bonds, and the second crosslinking aid is a polysiloxane oligomer containing alkenyl functional groups.

2. The organosilicon release composition according to claim 1, characterized in that, The first crosslinking aid is at least one of hydrogen-containing polymethylsiloxane oligomer, end-hydrogen-containing polydimethylsiloxane oligomer, and side-hydrogen-containing polydimethylsiloxane oligomer; the second crosslinking aid is at least one of vinyl-terminated polydimethylsiloxane oligomer, side-vinyl polydimethylsiloxane oligomer, and end-allyl polydimethylsiloxane oligomer.

3. The organosilicon release composition according to claim 1, characterized in that, The hydrogen-containing polysiloxane crosslinking agent is at least one of methylhydrosiloxane-dimethylsiloxane copolymer, high hydrogen content polymethylhydrosiloxane, and hydrogen-containing methyl / phenyl copolymer siloxane.

4. The organosilicon release composition according to claim 1, characterized in that, Based on parts by weight, the raw material components also include 2 to 7 parts of a non-migratory release force modifier, wherein the non-migratory release force modifier is at least one of terminal vinyl polydimethylsiloxane oligomer, side-chain vinyl-modified polydimethylsiloxane oligomer, and multifunctional vinyl polysiloxane oligomer.

5. The organosilicon release composition according to claim 1, characterized in that, The platinum catalyst is at least one of platinum-vinylsiloxane complex, platinum-olefin complex, and platinum-cyclopentadienyl complex.

6. The organosilicon release composition according to claim 1, characterized in that, The organic solvent is at least one of aromatic hydrocarbons, ketones, and C1-C4 aliphatic alcohols.

7. An organosilicon release film, characterized in that, It includes a substrate and an organosilicon release coating disposed on the surface of the substrate; the organosilicon release coating is formed by curing the organosilicon release composition according to any one of claims 1 to 6.

8. The organosilicon release film according to claim 7, characterized in that, The substrate is any one of PET, PI, PEN, PP, and PE, and the thickness of the substrate is 38~100μm.

9. A method for preparing an organosilicon release film as described in any one of claims 7-8, characterized in that, Includes the following steps: The substrate is subjected to corona treatment; After diluting and mixing the ultra-low peeling agent with an organic solvent, the first crosslinking aid, the second crosslinking aid, the platinum catalyst, and the hydrogen-containing polysiloxane crosslinking agent are added in sequence to obtain an organosilicon release composition. The organosilicon release composition is coated onto the surface of a substrate after corona treatment, and after heating and curing, an organosilicon release coating is formed on the surface of the substrate to obtain the organosilicon release film. When the raw material components of the organosilicon release composition include a non-migratory release force modifier, the non-migratory release force modifier is blended and diluted with the ultra-low peeling agent.

10. The method for preparing the organosilicon release film according to claim 9, characterized in that, The curing temperature is 120~150℃, and the curing time is 2~3 minutes.

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