A release agent and its preparation method

Abstract

This application relates to the field of release agents, and specifically discloses a release agent and a preparation method thereof. The release agent comprises the following components in parts by mass: 98-100 parts of vinyl silicone oil, 0.1-2 parts of inhibitor, 1.5-6 parts of crosslinking agent, 0.2-1 part of anchoring agent, 0.5-2 parts of platinum catalyst, and 0.2-3 parts of release force regulator; the release force regulator is an epoxy group-terminated alkyl fluorosilicone oil; the preparation method is: according to the ratio, mix and stir evenly vinyl silicone oil, inhibitor, crosslinking agent, anchoring agent, catalyst, and release force regulator to obtain the release agent. The release agent of this application has the advantages of low release force and high residual adhesion rate.

Description

Technical Field

[0001] The present application relates to the field of release agents, and more specifically, it relates to a release agent and a preparation method thereof. Background Art

[0002] The silicone release agent is coated and cured on the surface of paper or polyester film to form a dense silicone surface coating. Due to its low surface energy characteristics, the silicone release agent can play the roles of anti-sticking, ensuring the surface quality of products, and protecting the adhesive coating.

[0003] The most widely used solvent-free addition-curing silicone release agent in the market has good curing performance, is easy to use, is harmless to the environment, and can conveniently adjust the release force according to actual needs, and can meet the production requirements of the vast majority of products. The solvent-free silicone release agent is mainly composed of vinyl silicone oil, inhibitor, cross-linking agent, anchoring agent, catalyst, etc. The vinyl silicone oil undergoes a hydrosilylation reaction with the cross-linking agent under the action of a catalyst to cross-link and cure to form a silicone surface coating with low surface energy.

[0004] At present, according to the different release force requirements of different application scenarios, it is usually necessary to add release force additives to the release agent formula. For example, a light release force additive can reduce the release force, and a heavy release force additive can increase the release force. However, the addition of most light release force additives will lead to a decrease in the residual adhesion rate while reducing the release force, so there is room for improvement. Summary of the Invention

[0005] In order to obtain a release agent with low release force and high residual adhesion rate, the present application provides a release agent and a preparation method thereof.

[0006] In a first aspect, the present application provides a release agent, adopting the following technical solution:

[0007] A release agent, comprising the following components in parts by mass:

[0008] 98 - 100 parts of vinyl silicone oil,

[0009] 0.1 - 2 parts of inhibitor,

[0010] 1.5 - 6 parts of cross-linking agent,

[0011] 0.2 - 1 part of anchoring agent,

[0012] 0.5 - 2 parts of platinum catalyst,

[0013] 0.2 - 3 parts of release force regulator;

[0014] The release force regulator is an epoxy group-terminated alkyl fluorosilicone oil.

[0015] By adopting the above technical solution, under heating conditions, vinyl silicone oil reacts with a cross-linking agent under the action of a platinum catalyst to undergo a silylation reaction to cross-link and solidify to form an organic silicone coating with low surface energy. The anchoring agent can react with the cross-linking agent or the coating substrate to improve the adhesion of the organic silicone coating to the coating substrate, reduce the migration rate of the silicone oil and improve the residual adhesion rate. Epoxy-terminated alkyl fluorosilicone oil is used as a release force regulator. The alkyl fluorosilicone oil is beneficial for further reducing the surface energy of the organic silicone coating, reducing the release force, and improving the anti-sticking effect of the organic silicone surface coating. The blocked epoxy group can react with the surface hydroxyl group of the coating substrate to enhance the force between the release force regulator and the coating substrate, reduce the migration of the alkyl fluorosilicone oil to the surface of the organic silicone coating, reduce the migration rate of the silicone oil, and thus promote the improvement of the residual adhesion rate.

[0016] Preferably, the preparation method of the release force regulator is as follows:

[0017] Using hydroxyl-terminated alkyl fluorosilicone oil as raw material, a solid acid catalyst is added to the hydroxyl-terminated alkyl fluorosilicone oil, and under the protection of nitrogen, epichlorohydrin is slowly added dropwise. The reaction is stirred at 40-80°C for 1-3 hours, and then the solid acid catalyst and unreacted epichlorohydrin are removed to obtain an intermediate product.

[0018] Add a solid base and a quaternary ammonium salt catalyst to the intermediate product, react at 30-60° C. for 1-3 hours under nitrogen protection, and purify to obtain a release force regulator.

[0019] Preferably, the molar ratio of the hydroxyl-terminated alkyl fluorosilicone oil to epichlorohydrin is 1:(2-4).

[0020] Preferably, the mass of the solid acid catalyst is 0.1-2% of the total mass of the hydroxyl-terminated alkyl fluorosilicone oil and epichlorohydrin.

[0021] Preferably, the molar ratio of the hydroxyl-terminated alkyl fluorosilicone oil to the solid base is 1:(0.8-1.5); and the quaternary ammonium salt catalyst is 0.1-3% of the total mass of the hydroxyl-terminated alkyl fluorosilicone oil and the solid base.

[0022] By adopting the above technical solution, under the action of a solid acid catalyst, epichlorohydrin is ring-opened and reacts with a hydroxyl-terminated alkyl fluorosilicone oil to generate a chemical reaction, which is followed by dehydration to generate a chlorohydrin intermediate product. Then, in an alkaline environment, under the action of a quaternary ammonium salt catalyst, the chlorohydrin intermediate product removes hydrogen chloride and water to generate an epoxy-terminated alkyl fluorosilicone oil. The use of a solid acid or a solid base can obtain a stable acidic or alkaline environment and facilitates recovery. By continuously passing nitrogen, the generation of oxidation by-products is reduced.

[0023] Preferably, the preparation method of the hydroxyl-terminated alkyl fluorosilicone oil is as follows:

[0024] Using trifluoropropylmethylcyclotrisiloxane as a raw material, heat the trifluoropropylmethylcyclotrisiloxane at 40 - 60 °C for 1 - 3 h to dehydrate it, then add 1,3 - bis(3 - hydroxypropyl)tetramethyldisiloxane and an acidic catalyst thereto, stir and react at 40 - 60 °C for 1 - 3 h, neutralize, distill off low - boiling substances under reduced pressure, and filter to obtain a hydroxyl - terminated alkyl fluorosilicone oil.

[0025] Preferably, the molar ratio of the trifluoropropylmethylcyclotrisiloxane to 1,3 - bis(3 - hydroxypropyl)tetramethyldisiloxane is 1:(0.1 - 0.2).

[0026] Preferably, the mass of the acidic catalyst is 0.1 - 3% of the total mass of the trifluoropropylmethylcyclotrisiloxane and 1,3 - bis(3 - hydroxypropyl)tetramethyldisiloxane.

[0027] By adopting the above - mentioned technical solution, using 1,3 - bis(3 - hydroxypropyl)tetramethyldisiloxane as a capping agent, a hydroxyl - double - terminated alkyl fluorosilicone oil can be obtained under the action of an acidic catalyst; using trifluoropropylmethylcyclotrisiloxane as a polymerization monomer, the side chain of the alkyl fluorosilicone oil molecule contains - CF3, which is beneficial to reducing the surface energy of the silicone coating formed by the curing of the release agent and reducing the release force; by limiting the molar ratio of the trifluoropropylmethylcyclotrisiloxane to 1,3 - bis(3 - hydroxypropyl)tetramethyldisiloxane, while the release agent has better bonding fastness to the substrate, the silicon transfer of the release agent can be reduced and the residual adhesion rate can be improved.

[0028] Preferably, the viscosity of the vinyl silicone oil is 200 - 500 cP and the vinyl content is 0.35 - 1.0%.

[0029] By adopting the above - mentioned technical solution, by adjusting the vinyl content and viscosity of the vinyl silicone oil, the release agent product is easy to coat, reducing the possibility of sagging and shrinkage holes in the silicone coating due to too low viscosity, and reducing the possibility of poor leveling and uneven thickness in the silicone coating due to too high viscosity.

[0030] Preferably, the inhibitor is one or a combination of more than one of alkyne compounds and alkynol compounds.

[0031] By adopting the above - mentioned technical solution, the inhibitor can inhibit the cross - linking of the vinyl silicone oil and the cross - linker at room temperature, ensuring the room - temperature storage stability of the release agent solution.

[0032] Preferably, the anchoring agent is one or a combination of more than one of epoxypropoxypropyl - modified polydimethylmethylvinylsiloxane and epoxycyclohexyl - modified polydimethylmethylvinylsiloxane.

[0033] By adopting the above technical solution, the vinyl group in the anchoring agent molecule can crosslink with the crosslinking agent, improving the cohesion of the silicone coating and reducing the silicone oil migration rate. The epoxy group can react with the hydroxyl groups on the surface of the coated substrate, increasing the bonding fastness of the release agent to the coated substrate and anchoring the silicone coating on the coated substrate.

[0034] Preferably, the crosslinking agent is selected from one or a combination of two of trimethyl-terminated polymethylhydrogensiloxane and trimethyl-terminated polydimethylmethylhydrogensiloxane.

[0035] By adopting the above technical solution, the crosslinking agent molecule contains -SiH between its chains. During heat curing, -SiH can undergo an addition reaction with vinyl silicone oil, promoting the crosslinking and curing of vinyl silicone oil.

[0036] In a second aspect, the present application provides a method for preparing a release agent, adopting the following technical solution:

[0037] A method for preparing a release agent includes the following steps

[0038] Mix vinyl silicone oil, inhibitor, crosslinking agent, anchoring agent, catalyst, and release force regulator in proportion and stir evenly to obtain a release agent.

[0039] By adopting the above technical solution, a release agent with low release force and high residual adhesion rate can be obtained, improving the application effect of the release agent.

[0040] In summary, the present application has the following beneficial effects:

[0041] 1. The present application uses epoxy group-terminated alkyl fluorosilicone oil as a release force regulator. Alkyl fluorosilicone oil is beneficial for further reducing the surface energy of the silicone coating, reducing the release force, and improving the anti-sticking effect of the silicone surface coating. The terminated epoxy group can react with the surface hydroxyl groups of the coated substrate, enhancing the interaction between the release force regulator and the coated substrate, and can generate hydrogen bond interactions with the crosslinking agent, etc., improving the cohesion of the silicone coating, reducing the migration of alkyl fluorosilicone oil to the surface of the silicone coating, and reducing the silicone oil migration rate, thereby promoting the improvement of the residual adhesion rate;

[0042] 2. The present application preferably uses trifluoropropylmethylcyclotrisiloxane as a polymerization monomer and 1,3-bis(3-hydroxypropyl)tetramethyldisiloxane as a capping agent, and then obtains epoxy group-terminated alkyl fluorosilicone oil with a -CF3 group in the side chain and double-terminated epoxy groups through a two-step reaction with epichlorohydrin, which can effectively promote the improvement of the residual adhesion rate of the release agent and the reduction of the release force. Specific Embodiments

[0043] The following further elaborates on the present application with reference to embodiments.

[0044] Preparation Example

[0045] Preparation Example 1

[0046] This preparation example discloses a release force regulator, and the preparation method is as follows:

[0047] Add 1404 g (3 mol) of trifluoropropylmethylcyclotrisiloxane to the reactor, heat and dehydrate at 50 °C for 3 h, then add 75 g (0.3 mol) of 1,3-bis(3-hydroxypropyl)tetramethyldisiloxane and 14.8 g of acidic catalyst sulfuric acid (1 mol / L) thereto, stir and react at 40 °C for 3 h, add 20 g of sodium carbonate for neutralization, filter, and distill off low-boiling substances under reduced pressure at 140 °C to obtain a hydroxyl-terminated alkyl fluorosilicone oil with an average molecular weight of about 1400;

[0048] Take 1400 g (1 mol) of hydroxyl-terminated alkyl fluorosilicone oil and add it to the reactor, then add 16.8 g of solid acid catalyst zinc perchlorate, slowly dropwise add 277.5 g (3 mol) of epichlorohydrin under the protection of nitrogen, stir and react at 60 °C for 1 h, filter to remove the solid acid catalyst, and distill off low-boiling substances and unreacted epichlorohydrin under reduced pressure at 140 °C to obtain an intermediate product;

[0049] Add 40 g (1 mol) of solid sodium hydroxide and 16.8 g of tetraethylammonium chloride to the intermediate product, react at 45 °C for 2 h under the protection of nitrogen, filter, and distill off low-boiling substances under reduced pressure at 140 °C to obtain a release force regulator.

[0050] Preparation Example 2

[0051] The difference between this preparation example and Preparation Example 1 is only that the preparation method of the release force regulator is as follows:

[0052] Add 1404 g (3 mol) of trifluoropropylmethylcyclotrisiloxane to the reactor, heat and dehydrate at 50 °C for 3 h, then add 150 g (0.6 mol) of 1,3-bis(3-hydroxypropyl)tetramethyldisiloxane and 15.5 g of acidic catalyst sulfuric acid (1 mol / L) thereto, stir and react at 40 °C for 3 h, add 20 g of sodium carbonate for neutralization, filter, and distill off low-boiling substances under reduced pressure at 140 °C to obtain a hydroxyl-terminated alkyl fluorosilicone oil with an average molecular weight of about 1200;

[0053] Add 1200 g (1 mol) of hydroxyl-terminated alkyl fluorosilicone oil to a reactor, then add 14.8 g of solid acid catalyst zinc perchlorate. Under the protection of nitrogen, slowly dropwise add 277.5 g (3 mol) of epichlorohydrin, and stir and react at 60 °C for 1 h. Filter to remove the solid acid catalyst, and distill under reduced pressure at 140 °C to remove low-boiling substances and unreacted epichlorohydrin to obtain an intermediate product;

[0054] Add 40 g (1 mol) of solid sodium hydroxide and 14.8 g of tetraethylammonium chloride to the intermediate product. Under the protection of nitrogen, react at 45 °C for 2 h, filter, and distill under reduced pressure at 140 °C to remove low-boiling substances to obtain a release force regulator.

[0055] Preparation Example 3

[0056] The difference between this preparation example and Preparation Example 1 is only that the preparation method of the release force regulator is as follows:

[0057] Add 1404 g (3 mol) of trifluoropropylmethylcyclotrisiloxane to a reactor, heat and dehydrate at 50 °C for 3 h, then add 37.5 g (0.15 mol) of 1,3-bis(3-hydroxypropyl)tetramethyldisiloxane and 14.4 g of acidic catalyst sulfuric acid (1 mol / L) thereto. Stir and react at 40 °C for 3 h, add 20 g of sodium carbonate for neutralization, filter, and distill under reduced pressure at 140 °C to remove low-boiling substances to obtain a hydroxyl-terminated alkyl fluorosilicone oil with an average molecular weight of about 1800;

[0058] Add 1800 g (1 mol) of hydroxyl-terminated alkyl fluorosilicone oil to a reactor, then add 20.8 g of solid acid catalyst zinc perchlorate. Under the protection of nitrogen, slowly dropwise add 277.5 g (3 mol) of epichlorohydrin, and stir and react at 60 °C for 1 h. Filter to remove the solid acid catalyst, and distill under reduced pressure at 140 °C to remove low-boiling substances and unreacted epichlorohydrin to obtain an intermediate product;

[0059] Add 40 g (1 mol) of solid sodium hydroxide and 20.8 g of tetraethylammonium chloride to the intermediate product. Under the protection of nitrogen, react at 45 °C for 2 h, filter, and distill under reduced pressure at 140 °C to remove low-boiling substances to obtain a release force regulator.

[0060] Preparation Example 4

[0061] The difference between this preparation example and Preparation Example 1 is only that the preparation method of the release force regulator is as follows:

[0062] Add 1404 g (3 mol) of trifluoropropylmethylcyclotrisiloxane to a reactor, heat and dehydrate it at 50 °C for 3 h, then add 225 g (0.9 mol) of 1,3-bis(3-hydroxypropyl)tetramethyldisiloxane and 15.5 g of acidic catalyst sulfuric acid (1 mol / L) thereto, stir and react at 40 °C for 3 h, add 20 g of sodium carbonate for neutralization, filter, and distill off low-boiling substances under reduced pressure at 140 °C to obtain a hydroxyl-terminated alkyl fluorosilicone oil with an average molecular weight of about 900;

[0063] Take 900 g (1 mol) of hydroxyl-terminated alkyl fluorosilicone oil and add it to a reactor, then add 11.8 g of solid acid catalyst zinc perchlorate. Under the protection of nitrogen, slowly dropwise add 277.5 g (3 mol) of epichlorohydrin, stir and react at 60 °C for 1 h, filter to remove the solid acid catalyst, and distill off low-boiling substances and unreacted epichlorohydrin under reduced pressure at 140 °C to obtain an intermediate product;

[0064] Add 40 g (1 mol) of solid sodium hydroxide and 11.8 g of tetraethylammonium chloride to the intermediate product. Under the protection of nitrogen, react at 45 °C for 2 h, filter, and distill off low-boiling substances under reduced pressure at 140 °C to obtain a release force regulator.

[0065] Preparation Example 5

[0066] The difference between this preparation example and Preparation Example 1 is only that the preparation method of the release force regulator is as follows:

[0067] Add 1404 g (3 mol) of trifluoropropylmethylcyclotrisiloxane to a reactor, heat and dehydrate it at 50 °C for 3 h, then add 75 g (0.3 mol) of 1,3-bis(3-hydroxypropyl)tetramethyldisiloxane and 14.8 g of acidic catalyst sulfuric acid (1 mol / L) thereto, stir and react at 40 °C for 3 h, add 20 g of sodium carbonate for neutralization, filter, and distill off low-boiling substances under reduced pressure at 140 °C to obtain a hydroxyl-terminated alkyl fluorosilicone oil with an average molecular weight of about 1200;

[0068] Take 1200 g (1 mol) of hydroxyl-terminated alkyl fluorosilicone oil and add it to a reactor, then add 13.9 g of solid acid catalyst zinc perchlorate. Under the protection of nitrogen, slowly dropwise add 185 g (2 mol) of epichlorohydrin, stir and react at 60 °C for 1 h, filter to remove the solid acid catalyst, and distill off low-boiling substances and unreacted epichlorohydrin under reduced pressure at 140 °C to obtain an intermediate product;

[0069] Add 40 g (1 mol) of solid sodium hydroxide and 13.9 g of tetraethylammonium chloride to the intermediate product. Under the protection of nitrogen, react at 45 °C for 2 h, filter, and distill off low-boiling substances under reduced pressure at 140 °C to obtain a release force regulator.

[0070] Preparation Example 6

[0071] This preparation example is only different from Preparation Example 1 in that the release force regulator is prepared as follows:

[0072] Add 1404 g (3 mol) of trifluoropropylmethylcyclotrisiloxane to the reactor, heat and dehydrate at 50 °C for 3 h, then add 75 g (0.3 mol) of 1,3-bis(3-hydroxypropyl)tetramethyldisiloxane and 14.8 g of acidic catalyst sulfuric acid (1 mol / L), stir and react at 40 °C for 3 h, add 20 g of sodium carbonate for neutralization, filter, and remove low-boiling substances by vacuum distillation at 140 °C to obtain a hydroxyl-terminated alkyl fluorosilicone oil with an average molecular weight of about 1200;

[0073] Take 1200 g (1 mol) of hydroxyl-terminated alkyl fluorosilicone oil and add it to the reactor, then add 15.7 g of solid acid catalyst zinc perchlorate. Under the protection of nitrogen, slowly dropwise add 370 g (4 mol) of epichlorohydrin, stir and react at 60 °C for 1 h, filter to remove the solid acid catalyst, and remove low-boiling substances and unreacted epichlorohydrin by vacuum distillation at 140 °C to obtain an intermediate product;

[0074] Add 40 g (1 mol) of solid sodium hydroxide and 15.7 g of tetraethylammonium chloride to the intermediate product. Under the protection of nitrogen, react at 45 °C for 2 h, filter, and remove low-boiling substances by vacuum distillation at 140 °C to obtain a release force regulator.

[0075] Example

[0076] Example 1

[0077] This example discloses a release agent, which includes the following components by mass: 990 g of vinyl silicone oil, 10 g of inhibitor, 40 g of crosslinking agent, 5 g of anchoring agent, 10 g of platinum catalyst, and 20 g of release force regulator.

[0078] In this example, the vinyl silicone oil is end-vinyl polyorganosiloxane, with a viscosity range of 400 - 500 cP and a vinyl content of 0.35 - 0.45%; the inhibitor is methyl butynol; the crosslinking agent is trimethyl-terminated polydimethylmethylhydrogensiloxane; the anchoring agent is epoxypropoxypropyl-modified polydimethylmethylvinylsiloxane; the platinum catalyst is Karstedt catalyst, with the model Huaxiang EF234243; the release force regulator is prepared from Preparation Example 1.

[0079] The preparation method of the release agent is as follows:

[0080] Mix the above-mentioned masses of vinyl silicone oil, inhibitor, crosslinking agent, anchoring agent, and release force regulator, stir evenly, and then add the platinum catalyst and stir evenly to obtain a release agent.

[0081] Example 2

[0082] The difference between this example and Example 1 is only that the release agent comprises the following components by mass: 980 g of vinyl silicone oil, 20 g of inhibitor, 60 g of crosslinking agent, 10 g of anchoring agent, 20 g of platinum catalyst, and 30 g of the release force regulator prepared in Preparation Example 1.

[0083] Example 3

[0084] The difference between this example and Example 1 is only that the release agent comprises the following components by mass: 1000 g of vinyl silicone oil, 1 g of inhibitor, 15 g of crosslinking agent, 2 g of anchoring agent, 5 g of platinum catalyst, and 2 g of the release force regulator prepared in Preparation Example 1.

[0085] Example 4

[0086] The difference between this example and Example 1 is only that the release force regulator is prepared from Preparation Example 2.

[0087] Example 5

[0088] The difference between this example and Example 1 is only that the release force regulator is prepared from Preparation Example 3.

[0089] Example 6

[0090] The difference between this example and Example 1 is only that the release force regulator is prepared from Preparation Example 4.

[0091] Example 7

[0092] The difference between this example and Example 1 is only that the release force regulator is prepared from Preparation Example 5.

[0093] Example 8

[0094] The difference between this example and Example 1 is only that the release force regulator is prepared from Preparation Example 6.

[0095] Comparative Example

[0096] Comparative Example 1

[0097] The difference between this comparative example and Example 1 is only that the release agent comprises the following components by mass: 990 g of vinyl silicone oil, 10 g of inhibitor, 40 g of crosslinking agent, 5 g of anchoring agent, and 10 g of platinum catalyst.

[0098] Comparative Example 2

[0099] The difference between this comparative example and Example 1 is only that the release force regulator is an epoxy group-terminated alkyl silicone oil, and the preparation method of the release force regulator is as follows:

[0100] Add 792 g (3 mol) of triethyltrimethylcyclotrisiloxane to a reactor, heat and dehydrate it at 50 °C for 3 h, then add 75 g (0.3 mol) of 1,3-bis(3-hydroxypropyl)tetramethyldisiloxane and 8.7 g of acidic catalyst sulfuric acid (1 mol / L) thereto, stir and react at 40 °C for 3 h, add 20 g of sodium carbonate for neutralization, filter, and distill off low-boiling substances under reduced pressure at 140 °C to obtain a hydroxyl-terminated alkyl silicone oil with an average molecular weight of about 800;

[0101] Take 800 g (1 mol) of hydroxyl-terminated alkyl silicone oil and add it to a reactor, then add 10.8 g of solid acid catalyst zinc perchlorate. Under the protection of nitrogen, slowly dropwise add 277.5 g (3 mol) of epichlorohydrin, stir and react at 60 °C for 1 h, filter to remove the solid acid catalyst, and distill off low-boiling substances and unreacted epichlorohydrin under reduced pressure at 140 °C to obtain an intermediate product;

[0102] Add 40 g (1 mol) of solid sodium hydroxide and 10.8 g of tetraethylammonium chloride to the intermediate product, react at 45 °C for 2 h under nitrogen protection, filter, and distill off low-boiling substances under reduced pressure at 140 °C to obtain a release force regulator.

[0103] Comparative Example 3

[0104] The difference between this comparative example and Example 1 is only that the release force regulator is a hydroxyl-terminated alkyl fluorosilicone oil, and the preparation method of the release force regulator is as follows:

[0105] Add 1404 g (3 mol) of trifluoropropylmethylcyclotrisiloxane to a reactor, heat and dehydrate it at 50 °C for 3 h, then add 75 g (0.3 mol) of 1,3-bis(3-hydroxypropyl)tetramethyldisiloxane and 14.8 g of acidic catalyst sulfuric acid (1 mol / L) thereto, stir and react at 40 °C for 3 h, add 20 g of sodium carbonate for neutralization, filter, and distill off low-boiling substances under reduced pressure at 140 °C to obtain a release force regulator.

[0106] Performance detection test

[0107] Coat the release agents prepared in each example and each comparative example on a film substrate respectively, with a coating amount of 1.1 gsm, and cure in an oven at 140 °C for 20 seconds to obtain a silicone release film.

[0108] Test 1: Stick the Tesa 7475 standard tape on the silicone release film, roll the sample back and forth twice with a standard test roller, press the sample with a standard stainless steel pressing strip, place it in an oven at 23 °C for 20 h, remove the pressing strip, let it stand at room temperature for 1 h, and test the 180° peel strength at a speed of 0.3 m / min on a tensile testing machine to obtain the room temperature release force;

[0109] Test 2: Stick the Tesa 7475 standard tape on the silicone release film, roll the sample back and forth twice with a standard test roller, press the sample with a standard stainless steel pressing strip, place it in an oven at 70 °C for 20 h, remove the pressing strip, place it at room temperature for 1 h, and test the 180° peel strength at a speed of 0.3 m / min on a tensile testing machine to obtain the release force after high-temperature aging;

[0110] Test 3: Stick the Nitto 31B tape with a width of 25 mm on the silicone release film according to the standard method, roll the sample back and forth twice with a standard test roller, press the sample with a standard stainless steel pressing strip and place it in an oven at 23 °C or 70 °C for 20 h, take it out and place it at room temperature for 1 h. Then peel the Nitto 31B tape from the silicone release film, stick it on a clean PET film, and place it under a standard pressure of 70 g / cm 2 , at 23 ± 2 °C and a relative humidity of 50% for 2 h, and then conduct a 180° peel at 0.3 m / min to obtain the peel strength, and take the average value L1;

[0111] Stick the Nitto 31B tape with a width of 25 mm on a clean PET film, and place it under a standard pressure of 70 g / cm 2 , at 23 ± 2 °C and a relative humidity of 50% for 2 h, and then conduct a 180° peel at 0.3 m / min to obtain the peel strength, and take the average value L0;

[0112] Residual adhesion rate (%) = Peel strength L1 of the peeled test tape / Peel strength L0 of the blank standard sample × 100%;

[0113] The results are summarized in Table 1.

[0114] Table 1

[0115]

[0116]

[0117] Combined with Examples 1-3, Comparative Example 1 and Table 1, it can be seen that by referring to the formula and preparation method disclosed in the present application, adding an epoxy group-terminated alkyl fluorosilicone oil as a release force regulator in the release agent can enable the release film to have a low release force and a high residual adhesion rate; at the same time, the change range of the residual adhesion rate of the silicone release film after high-temperature aging is reduced, indicating that the aging resistance of the silicone release film is improved.

[0118] Combined with Example 1 and Comparative Example 2 and with reference to Table 1, it can be seen that when using the epoxy group-terminated alkyl fluorosilicone oil prepared with trifluoropropylmethylcyclotrisiloxane as the polymerization monomer as the release agent, compared with using the epoxy group-terminated alkyl silicone oil prepared with triethyltrimethylcyclotrisiloxane as the polymerization monomer as the release agent, it can endow the silicone release film with a lower release force and better aging resistance. This may be because the side chain -CF3 group of the epoxy group-terminated alkyl fluorosilicone oil can migrate to the surface of the silicone release film to reduce the surface energy, and the reaction activity of the fluoroalkyl group with active groups such as hydroxyl groups on the tape surface is poor, reducing the possibility of adverse reactions between the tape and the silicone release film, which is beneficial to ensuring the stability of the residual adhesion rate; at the same time, the doping of fluorine elements can also improve the aging resistance of the silicone coating.

[0119] Combined with Example 1 and Comparative Example 3 and with reference to Table 1, it can be seen that double-capping the alkylfluorosilane with epoxy groups can improve the residual adhesion rate of the silicone release film. This may be because the capped epoxy groups can react with the hydroxyl groups on the substrate surface and participate in the formation of a hydrogen bond cross-linking network in the silicone coating, reducing the migration of the siloxane segments, which is then beneficial to improving the residual adhesion rate.

[0120] Combined with Example 1 and Examples 4 - 6 and with reference to Table 1, it can be seen that with the addition of the capping agent 1,3-bis(3-hydroxypropyl)tetramethyldisiloxane, the average molecular weight of the dihydroxy group-terminated alkyl fluorosilicone oil generated by the reaction decreases, and this leads to a certain increase in the residual adhesion rate; this may be because, with the increase in the dosage of the capping agent, the average molecular weight of the dihydroxy group-terminated alkyl fluorosilicone oil decreases, the hydroxyl group content increases to a certain extent, and after reacting with epichlorohydrin, the epoxy group content increases.

[0121] On the one hand, the hydroxyl groups on the substrate surface can react with the epoxy groups in the anchoring agent to improve the anchoring effect of the release agent on the substrate and enhance the bonding fastness of the release agent. On the other hand, they can react with the release force regulator to reduce silicon transfer; however, the content of hydroxyl groups on the substrate surface is limited. When the epoxy group content in the release force regulator is too high, it may lead to a reduction in the anchoring effect of the anchoring agent, a decrease in the bonding fastness of the release agent to the substrate, and may also result in incomplete combination of the release force regulator molecules with the substrate, causing an increase in silicon transfer and a decrease in the residual adhesion rate.

[0122] In summary, within the scope disclosed in this application, restricting the molar ratio of trifluoropropylmethylcyclotrisiloxane to 1,3-bis(3-hydroxypropyl)tetramethyldisiloxane to 1:(0.1 - 0.2) can enable the release agent to have better bonding fastness to the substrate while reducing the silicon transfer of the release agent and increasing the residual adhesion rate.

[0123] The amount of the dihydroxy endblocker has almost negligible effect on the average molecular weight of the alkyl fluorosilicone oil, indicating that by controlling the addition amount of the endblocker 1,3-bis(3-hydroxypropyl)tetramethyldisiloxane according to the method disclosed in this application, an alkyl fluorosilicone oil with relatively stable properties can be obtained.

[0124] Combined with Example 1, Example 5, Example 6 and Table 1, it can be seen that by adding an appropriate excess of epichlorohydrin to react with the alkyl fluorosilicone oil with hydroxyl double end groups, the blocked hydroxyl groups can be more completely converted into epoxy groups, further ensuring the stability of the residual adhesion rate.

[0125] This specific embodiment is only an interpretation of this application and does not limit this application. After reading this specification, those skilled in the art can make modifications to this embodiment without creative contributions as needed, but as long as they are within the scope of the claims of this application, they are protected by the patent law.

Claims

1. A release agent, characterized in that, The components are as follows by mass parts: 98 - 100 parts of vinyl silicone oil, 0.1 - 2 parts of inhibitor, 1.5 - 6 parts of crosslinking agent, 0.2 - 1 part of anchoring agent, 0.5 - 2 parts of platinum catalyst, 0.2 - 3 parts of release force regulator; The release force regulator is an epoxy - terminated alkyl fluorosilicone oil; The preparation method of the release force regulator is as follows: Using hydroxy - terminated alkyl fluorosilicone oil as the raw material, adding a solid acid catalyst to the hydroxy - terminated alkyl fluorosilicone oil, slowly dropping epichlorohydrin under the protection of nitrogen, stirring and reacting at 40 - 80 °C for 1 - 3 h, then removing the solid acid catalyst and unreacted epichlorohydrin to obtain an intermediate product; Adding a solid base and a quaternary ammonium salt catalyst to the intermediate product, reacting at 30 - 60 °C for 1 - 3 h under nitrogen protection, and purifying to obtain the release force regulator; Using trifluoropropylmethylcyclotrisiloxane as the raw material, heating and dehydrating trifluoropropylmethylcyclotrisiloxane at 40 - 60 °C for 1 - 3 h, then adding 1,3 - bis(3 - hydroxypropyl)tetramethyldisiloxane and an acidic catalyst, stirring and reacting at 40 - 60 °C for 1 - 3 h, neutralizing, distilling under reduced pressure to remove low - boiling substances, and filtering to obtain hydroxy - terminated alkyl fluorosilicone oil; The molar ratio of the trifluoropropylmethylcyclotrisiloxane to 1,3 - bis(3 - hydroxypropyl)tetramethyldisiloxane is 1:(0.1 - 0.2); The anchoring agent is one or a combination of more than one of epoxypropoxypropyl - modified polydimethylmethylvinylsiloxane and epoxycyclohexyl - modified polydimethylmethylvinylsiloxane.

2. The release agent according to claim 1, characterized in that: The molar ratio of the hydroxy - terminated alkyl fluorosilicone oil to epichlorohydrin is 1:(2 - 4).

3. The release agent according to claim 1, characterized in that: The viscosity of the vinyl silicone oil is 200 - 500 cP, and the vinyl content is 0.35 - 1.0%.

4. The release agent according to claim 1, characterized in that: The inhibitor is one or a combination of more than one of alkyne compounds and alkynol compounds.

5. The release agent according to claim 1, characterized in that: The crosslinking agent is selected from one or a combination of two of trimethyl - terminated polymethylhydrosiloxane and trimethyl - terminated polydimethylmethylhydrosiloxane.

6. A method for preparing a release agent according to any one of claims 1-5, characterized in that: It includes the following steps: Mix and stir evenly vinyl silicone oil, inhibitor, crosslinking agent, anchoring agent, catalyst, and release force regulator according to the ratio to obtain a release agent.

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