Photocurable Emulsion-Type Semi-Permanent Silicon-Containing Release Agent and Its Preparation Method and Application

Abstract

The present invention discloses a photocurable emulsion-type semi-permanent silicone release agent, its preparation method and application, belonging to the technical field of fine silicone chemicals. The method includes the following steps: preparation of mercaptopropyl polysiloxane; synthesis of vinyl silicone resin; emulsification. The main components of the product of the present invention are mercaptopropyl siloxane and vinyl silicone resin. The functional groups of the two can undergo a "thiol-ene addition reaction" under the action of a photoinitiator through UV ultraviolet rays in sunlight without additional thermal curing. The emulsion obtained by emulsifying mercaptopropyl siloxane and vinyl silicone resin has good effects in the demolding of PU products and epoxy resin products, will not cause product contamination due to the transfer of the release agent, nor will there be a phenomenon of poor adhesion of the release agent to the mold resulting in a dirty mold. Moreover, after being made into an emulsion under the action of an emulsifier, it can be stored in the dark for at least 3 months, truly achieving environmental protection and water-based properties.

Description

Technical Field

[0001] The invention belongs to the technical field of organic silicon fine chemical industry, and more specifically relates to a light-curable emulsion-type semi-permanent silicon-containing release agent and a preparation method and application thereof. Background Art

[0002] Silicone release agents are divided into solvent-free type, solvent type, water-dispersible type, ointment type, and aerosol type according to their properties; they are divided into dimethyl silicone oil and secondary processed products, high molar mass dimethyl silicone oil anionic emulsion, polyether modified silicone oil solution or emulsion, alkyl aromatic silicone oil and its emulsion, silicone resin or a mixture of silicone oil and silicone resin, and hydroxy silicone oil emulsion according to their crude oil structure; they are divided into polyurethane and rubber and plastic product release agents, metal die-casting release agents, tire release agents, internal release agents, and others according to their industrial use.

[0003] The preparation method in the existing patent (application number 202110172960.6) uses a mixed emulsification technology, which only emulsifies the silicone oil in the emulsifier without any relevant secondary film-forming reaction, resulting in poor adhesion of the release agent to the substrate. During the demolding process, the release agent is migrated to the surface of the demolded object, thereby causing contamination of the demolded object.

[0004] The existing patent (application number 202010769792.4) discloses a macromolecular hydroxyl silicone oil emulsion. When no curing agent is added to this type of emulsion, the reactivity of the hydroxyl group cannot be stimulated. The final emulsion coating is a colloid, which aggravates the oil pollution on the mold surface and requires frequent mold cleaning.

[0005] The existing patent (application number 202210229774.6) discloses that the semi-permanent release agent is a resin-type release agent that requires heating to undergo a secondary reaction. Although the adhesion of this type of release agent is improved, there are not enough methyl and methylene groups on the surface of the resin coating after curing, and the resin contains insufficient silicon, which makes demolding difficult.

[0006] Therefore, how to develop a photocurable emulsion-type semi-permanent silicone-containing release agent that has a good demolding effect, does not cause product contamination caused by mold release agent transfer, does not cause mold dirtying due to poor mold release agent adhesion, and is truly environmentally friendly and water-based is a technical problem that technical personnel in this field urgently need to solve. Summary of the invention

[0007] In view of this, the present invention provides a photocurable emulsion-type semi-permanent silicon-containing release agent and a preparation method and application thereof.

[0008] In order to achieve the above object, the present invention adopts the following technical solution:

[0009] A method for preparing a light-curable emulsion-type semi-permanent silicon-containing release agent comprises the following steps:

[0010] (1) Preparation of mercaptopropyl polysiloxane: Mix mercaptopropyl dimethyldialkoxysilane with water and stir. A hydrolysis reaction occurs at room temperature to obtain a mercaptopropyl dimethyl dihydroxy intermediate.

[0011] Mix the mercaptopropyl dimethyl dihydroxy intermediate, hexamethylcyclotrisiloxane, hexamethyldisiloxane, and a basic catalyst and stir to carry out a polymerization reaction to obtain mercaptopropyl polysiloxane.

[0012] (2) Synthesis of vinyl silicone resin:

[0013] (a) Mix vinyldimethyldialkoxysilane with water and stir. A hydrolysis reaction occurs at room temperature to obtain vinyldimethylsilanol.

[0014] (b) Mix vinyltrialkoxysilane with water and stir. A hydrolysis reaction occurs at room temperature to obtain vinyltrisilanol.

[0015] (c) Mix tetraalkoxysilane with water and stir. A hydrolysis reaction occurs at room temperature to obtain tetrasilanol.

[0016] (d) Mix vinyldimethylsilanol, vinyltrisilanol, tetrasilanol, and an acidic catalyst and stir to carry out a polycondensation reaction to obtain vinyl silicone resin.

[0017] (3) Emulsification: Mix mercaptopropyl polysiloxane, vinyl silicone resin, an emulsifier, water, and a photoinitiator and carry out high-speed shear emulsification to obtain the above-mentioned photocurable emulsion-type semi-permanent silicone-containing mold release agent.

[0018] Furthermore, in step (1), the mass ratio of the above-mentioned mercaptopropyl dimethyldialkoxysilane to water is 1:(1 - 10), and the mass ratio of the mercaptopropyl dimethyldialkoxysilane, hexamethylcyclotrisiloxane, hexamethyldisiloxane, and the basic catalyst is: (20 - 35):(58 - 75):(6 - 10):(0.01 - 0.05).

[0019] Furthermore, in steps (1)-(3), the above-mentioned water is distilled water.

[0020] Furthermore, in step (1), the above-mentioned basic catalyst is tetramethylammonium hydroxide.

[0021] Furthermore, in step (1), the above-mentioned hydrolysis reaction time is 2 - 5 hours; the above-mentioned polymerization reaction temperature is 100 - 110 °C, and the polymerization reaction time is 6 - 12 hours.

[0022] Further, in step (a), the mass ratio of the above vinyl dimethyl alkoxysilane to water is 1:(1 - 10); in step (b), the mass ratio of the above vinyl trialkoxysilane to water is 1:(1 - 10); in step (c), the mass ratio of the above tetraalkoxysilane to water is 1:(1 - 10), and the mass ratio of the above vinyl dimethyl alkoxysilane, vinyl trialkoxysilane, tetraalkoxysilane and acidic catalyst is (4 - 10):(20 - 35):(60 - 75):(1.5 - 3).

[0023] Further, in step (d), the above acidic catalyst is concentrated sulfuric acid.

[0024] Further, in step (d), the concentration of the above concentrated sulfuric acid is 98%.

[0025] Further, in step (a), the above hydrolysis reaction time is 2 - 5 hours; in step (b), the above hydrolysis reaction time is 2 - 5 hours; in step (c), the above hydrolysis reaction time is 2 - 5 hours; in step (d), the above polycondensation reaction temperature is 60 - 80 °C, and the polycondensation reaction time is 5 - 10 hours.

[0026] Further, in steps (1)-(2), the above stirring speed is 60 - 200 r / min.

[0027] Further, in step (3), the mass percentages of the above raw materials used for emulsification are respectively: mercaptopropyl polysiloxane 10 - 30%, vinyl silicone resin 5 - 20%, emulsifier 5 - 10%, water 45 - 65%, photoinitiator 0.1 - 0.5%.

[0028] Further, in step (3), the above high-speed shearing speed is 2000 - 3000 r / min, and the emulsification time is 45 - 90 min.

[0029] Further, in step (3), the above emulsifier is isodecyl polyoxyethylene ether and / or isotridecyl polyoxyethylene ether, and the above photoinitiator is hydroxycyclohexyl phenyl ketone.

[0030] The present invention also provides a photocurable emulsion-type semi-permanent silicone-containing release agent prepared by the above method.

[0031] The present invention also provides an application of the above photocurable emulsion-type semi-permanent silicone-containing release agent in the demolding of PU products and epoxy resin products.

[0032] In the above step (1), the hydrolysis reaction formula of mercaptopropyl dimethyl dialkoxysilane is as follows:

[0033]

[0034] wherein, R = Me, Et, Bu;

[0035] The synthesis reaction formula of mercaptopropyl polysiloxane is as follows:

[0036]

[0037] Among them, m = 10 - 20, n = 5 - 10;

[0038] In the above step (2), the hydrolysis reaction formula of vinyldimethylalkoxysilane is as follows:

[0039]

[0040] Among them, R = Me, Et, Bu;

[0041] The hydrolysis reaction formula of vinyltrialkoxysilane is as follows:

[0042]

[0043] Among them, R = Me, Et, Bu;

[0044] The hydrolysis reaction formula of tetraalkoxysilane is as follows:

[0045]

[0046] Among them, R = Me, Et, Bu;

[0047] The synthesis reaction formula of vinyl silicone resin is as follows:

[0048]

[0049] The above Me represents methyl, Et represents ethyl, Bu represents butyl, and Vi represents vinyl.

[0050] The beneficial effects of the present invention: The product of the present invention combines the technical idea of silicone oil and silicone resin composite release agents. Through the "mercapto / vinyl addition reaction" of mercaptopropyl polysiloxane and vinyl silicone resin catalyzed by a photoinitiator, a silicone resin coating with high adhesion and semi-permanent properties is obtained. And under the action of an emulsifier, the final product is prepared into an emulsion, avoiding the problem of excessive VOCS emissions caused by excessive use of solvents.

[0051] The final product of the present invention is an aqueous emulsion. With a specific photoinitiator, it can undergo a "thiol-ene addition reaction" through the UV ultraviolet rays in sunlight without additional heat curing. The obtained demoulding coating has high adhesion and good flatness, and shows excellent effects in demoulding PU products and epoxy resin products. It will not cause product contamination due to the transfer of the demoulding agent, nor will it cause dirty moulds on the mould due to poor adhesion of the demoulding agent. The surface of the PU tyre demoulded by the demoulding agent is bright and free of oil stains, and the epoxy resin product demoulded has a regular shape and no defects. Moreover, through repeated freeze-thaw experiments on the emulsion demoulding agent, it can be seen that its stability is relatively good.

[0052] The main components of the product of the present invention are mercaptopropyl siloxane and vinyl silicone resin. Their functional groups can undergo a "thiol-ene addition reaction" through the UV ultraviolet rays in sunlight under the action of a photoinitiator without additional heat curing. The emulsion obtained by emulsifying mercaptopropyl siloxane and vinyl silicone resin shows good effects in demoulding PU products and epoxy resin products. It will not cause product contamination due to the transfer of the demoulding agent, nor will it cause dirty moulds on the mould due to poor adhesion of the demoulding agent. And after being made into an emulsion under the action of an emulsifier, it can be stored away from light for at least 3 months, truly achieving environmental protection and water-based properties. Description of the Drawings

[0053] Figure 1 It is a process flow chart for the preparation of the photocurable emulsion-type semi-permanent silicon-containing demoulding agent of the present invention;

[0054] Figure 2 It is a schematic diagram of the microscopic reaction during the demoulding process of the photocurable emulsion-type semi-permanent silicon-containing demoulding agent of the present invention;

[0055] Figure 3 It is a diagram showing a bright and flat coating formed after water evaporation when the photocurable emulsion-type semi-permanent silicon-containing demoulding agent prepared in Example 1 of the present invention is sprayed on a stainless steel plate at 85 °C;

[0056] Figure 4 It is a complete PU tyre diagram obtained from the demoulding test of the photocurable emulsion-type semi-permanent silicon-containing demoulding agent prepared in Example 2 of the present invention at a certain PU tyre factory in Xiamen;

[0057] Figure 5 It is a complete epoxy resin product diagram obtained from the demoulding test of the photocurable emulsion-type semi-permanent silicon-containing demoulding agent prepared in Example 3 of the present invention at a certain epoxy resin product factory in Jingdezhen;

[0058] Figure 6 It is a state diagram of the photocurable emulsion-type semi-permanent silicon-containing demoulding agent prepared in Example 1 of the present invention after 2 freeze-thaw experiments and a 3-month heat storage experiment at 54 ± 2 °C. Detailed Embodiments

[0059] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Apparently, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0060] Example 1

[0061] A preparation method of a photocurable emulsion-type semi-permanent silicone release agent, comprising the following steps:

[0062] (1) Preparation of mercaptopropyl polysiloxane: Mix 25 kg of mercaptopropyl dimethyldimethoxysilane with 25 kg of distilled water and stir at room temperature for a hydrolysis reaction for 2.5 hours at a stirring speed of 200 r / min to obtain a mercaptopropyl dimethyldihydroxy intermediate;

[0063] Mix the obtained mercaptopropyl dimethyldihydroxy intermediate, 68 kg of hexamethylcyclotrisiloxane, 7 kg of hexamethyldisiloxane and 0.015 kg of tetramethylammonium hydroxide and stir for a polymerization reaction for 8 hours at a stirring speed of 60 r / min and a polymerization reaction temperature of 108 °C to obtain mercaptopropyl polysiloxane;

[0064] (2) Synthesis of vinyl silicone resin:

[0065] (a) Mix 6 kg of vinyldimethylmethoxysilane with 12 kg of distilled water and stir at room temperature for a hydrolysis reaction for 2 hours at a stirring speed of 180 r / min to obtain vinyldimethylsilanol;

[0066] (b) Mix 28 kg of vinyltrimethoxysilane with 60 kg of distilled water and stir at room temperature for a hydrolysis reaction for 2.5 hours at a stirring speed of 150 r / min to obtain vinyltrisilanol;

[0067] (c) Mix 66 kg of tetramethoxysilane with 130 kg of distilled water and stir at room temperature for a hydrolysis reaction for 3 hours at a stirring speed of 70 r / min to obtain tetrasilanol;

[0068] (d) Mix the obtained vinyldimethylsilanol, vinyltrisilanol, tetrasilanol and 2.7 kg of concentrated sulfuric acid with a concentration of 98% and stir for a polycondensation reaction for 5 hours at a stirring speed of 80 r / min and a polycondensation reaction temperature of 65 °C to obtain vinyl silicone resin;

[0069] (3) Emulsification: 15 kg of mercaptopropyl polysiloxane, 12 kg of vinyl silicone resin, 8 kg of isomeric tridecanol polyoxyethylene ether, 64.7 kg of distilled water, and 0.3 kg of hydroxycyclohexyl phenyl ketone were mixed and emulsified by high-speed shearing to obtain the above-mentioned photocurable emulsion-type semi-permanent silicone-containing release agent. The high-speed shearing speed was 2200 r / min, and the emulsification time was 50 min.

[0070] Example 2

[0071] A preparation method of a photocurable emulsion-type semi-permanent silicone-containing release agent, comprising the following steps:

[0072] (1) Preparation of mercaptopropyl polysiloxane: 30 kg of mercaptopropyl dimethyldiethoxysilane and 35 kg of distilled water were mixed and stirred to undergo a hydrolysis reaction at room temperature for 4 hours, with a stirring speed of 80 r / min, to obtain a mercaptopropyl dimethyl dihydroxy intermediate;

[0073] The obtained mercaptopropyl dimethyl dihydroxy intermediate, 60 kg of hexamethylcyclotrisiloxane, 10 kg of hexamethyldisiloxane, and 0.02 kg of tetramethylammonium hydroxide were mixed and stirred to undergo a polymerization reaction for 10 hours, with a stirring speed of 150 r / min and a polymerization reaction temperature of 105 °C, to obtain mercaptopropyl polysiloxane;

[0074] (2) Synthesis of vinyl silicone resin:

[0075] (a) 8 kg of vinyldimethylethoxysilane and 70 kg of distilled water were mixed and stirred to undergo a hydrolysis reaction at room temperature for 3.5 hours, with a stirring speed of 140 r / min, to obtain vinyldimethylsilanol;

[0076] (b) 32 kg of vinyltriethoxysilane and 50 kg of distilled water were mixed and stirred to undergo a hydrolysis reaction at room temperature for 3 hours, with a stirring speed of 140 / min, to obtain vinyltrisilanol;

[0077] (c) 60 kg of tetraethoxysilane and 140 kg of distilled water were mixed and stirred to undergo a hydrolysis reaction at room temperature for 4 hours, with a stirring speed of 80 r / min, to obtain tetrasilanol;

[0078] (d) The obtained vinyldimethylsilanol, vinyltrisilanol, tetrasilanol, and 2.8 kg of concentrated sulfuric acid with a concentration of 98% were mixed and stirred to undergo a polycondensation reaction for 6 hours, with a stirring speed of 80 r / min and a polycondensation reaction temperature of 70 °C, to obtain vinyl silicone resin;

[0079] (3) Emulsification: Mix 25 kg of mercaptopropyl polysiloxane, 18 kg of vinyl silicone resin, 7 kg of isomeric tridecanol polyoxyethylene ether, 49.8 kg of distilled water, and 0.2 kg of hydroxycyclohexyl phenyl ketone, and perform high-speed shear emulsification to obtain the above-mentioned photocurable emulsion-type semi-permanent silicone-containing release agent. The high-speed shear speed is 2500 r / min, and the emulsification time is 60 min.

[0080] Example 3

[0081] A preparation method of a photocurable emulsion-type semi-permanent silicone-containing release agent, comprising the following steps:

[0082] (1) Preparation of mercaptopropyl polysiloxane: Mix 22 kg of mercaptopropyl dimethyldipropoxysilane with 60 kg of distilled water and stir at room temperature for 4.5 hours to carry out a hydrolysis reaction at a stirring speed of 70 r / min to obtain a mercaptopropyl dimethyl dihydroxy intermediate;

[0083] Mix the obtained mercaptopropyl dimethyl dihydroxy intermediate, 72 kg of hexamethylcyclotrisiloxane, 6 kg of hexamethyldisiloxane, and 0.035 kg of tetramethylammonium hydroxide, and stir to carry out a polymerization reaction for 10 hours at a stirring speed of 70 r / min and a polymerization reaction temperature of 107 °C to obtain mercaptopropyl polysiloxane;

[0084] (2) Synthesis of vinyl silicone resin:

[0085] (a) Mix 9 kg of vinyldimethylmethoxysilane with 36 kg of distilled water and stir at room temperature for 4 hours to carry out a hydrolysis reaction at a stirring speed of 80 r / min to obtain vinyldimethylsilanol;

[0086] (b) Mix 30 kg of vinyltriethoxysilane with 70 kg of distilled water and stir at room temperature for 4.5 hours to carry out a hydrolysis reaction at a stirring speed of 90 r / min to obtain vinyltrisilanol;

[0087] (c) Mix 61 kg of tetrapropoxysilane with 70 kg of distilled water and stir at room temperature for 5 hours to carry out a hydrolysis reaction at a stirring speed of 90 r / min to obtain tetrasilanol;

[0088] (d) Mix the obtained vinyldimethylsilanol, vinyltrisilanol, tetrasilanol, and 1.8 kg of concentrated sulfuric acid with a concentration of 98%, and stir to carry out a polycondensation reaction for 8 hours at a stirring speed of 90 r / min and a polycondensation reaction temperature of 60 °C to obtain vinyl silicone resin;

[0089] (3) Emulsification: 24 kg of mercaptopropyl polysiloxane, 19 kg of vinyl silicone resin, 9 kg of isodecyl polyoxyethylene ether, 47.9 kg of distilled water, and 0.1 kg of hydroxycyclohexyl phenyl ketone were mixed and emulsified by high-speed shearing to obtain the above-mentioned photocurable emulsion-type semi-permanent silicone-containing release agent. The high-speed shearing speed was 2700 r / min, and the emulsification time was 80 min.

[0090] Example 4

[0091] A preparation method of a photocurable emulsion-type semi-permanent silicone-containing release agent, comprising the following steps:

[0092] (1) Preparation of mercaptopropyl polysiloxane: 31 kg of mercaptopropyl dimethyldiethoxysilane and 70 kg of distilled water were mixed and stirred to carry out a hydrolysis reaction at room temperature for 3 hours, and the stirring speed was 110 r / min to obtain a mercaptopropyl dimethyl dihydroxy intermediate;

[0093] The obtained mercaptopropyl dimethyl dihydroxy intermediate, 68 kg of hexamethylcyclotrisiloxane, 10 kg of hexamethyldisiloxane, and 0.025 kg of tetramethylammonium hydroxide were mixed and stirred to carry out a polymerization reaction for 8 hours, the stirring speed was 150 r / min, and the polymerization reaction temperature was 107 °C to obtain mercaptopropyl polysiloxane;

[0094] (2) Synthesis of vinyl silicone resin:

[0095] (a) 8 kg of vinyldimethylmethoxysilane and 15 kg of distilled water were mixed and stirred to carry out a hydrolysis reaction at room temperature for 2 hours, and the stirring speed was 120 r / min to obtain vinyldimethylsilanol;

[0096] (b) 30 kg of vinyltriethoxysilane and 30 kg of distilled water were mixed and stirred to carry out a hydrolysis reaction at room temperature for 3 hours, and the stirring speed was 100 r / min to obtain vinyltrisilanol;

[0097] (c) 62 kg of tetraethoxysilane and 80 kg of distilled water were mixed and stirred to carry out a hydrolysis reaction at room temperature for 3 hours, and the stirring speed was 100 r / min to obtain tetrasilanol;

[0098] (d) The obtained vinyldimethylsilanol, vinyltrisilanol, tetrasilanol, and 2.3 kg of concentrated sulfuric acid with a concentration of 98% were mixed and stirred to carry out a polycondensation reaction for 5.5 hours, the stirring speed was 90 r / min, and the polycondensation reaction temperature was 65 °C to obtain vinyl silicone resin;

[0099] (3) Emulsification: 27 kg of mercaptopropyl polysiloxane, 15 kg of vinyl silicone resin, 9 kg of isodecyl polyoxyethylene ether, 48.5 kg of distilled water, and 0.5 kg of hydroxycyclohexyl phenyl ketone were mixed and emulsified by high-speed shearing to obtain the above-mentioned photocurable emulsion-type semi-permanent silicone-containing release agent. The high-speed shearing speed was 3000 r / min, and the emulsification time was 90 min.

[0100] Example 5

[0101] Preparation method of a photocurable emulsion-type semi-permanent silicone-containing release agent, comprising the following steps:

[0102] (1) Preparation of mercaptopropyl polysiloxane: 28 kg of mercaptopropyl dimethyldimethoxysilane was mixed with 280 kg of distilled water and stirred at room temperature for a hydrolysis reaction for 3 hours at a stirring speed of 200 r / min to obtain a mercaptopropyl dimethyldihydroxy intermediate;

[0103] The obtained mercaptopropyl dimethyldihydroxy intermediate, 75 kg of hexamethylcyclotrisiloxane, 10 kg of hexamethyldisiloxane, and 0.05 kg of tetramethylammonium hydroxide were mixed and stirred for a polymerization reaction for 12 hours at a stirring speed of 200 r / min, and the polymerization reaction temperature was 110 °C to obtain mercaptopropyl polysiloxane;

[0104] (2) Synthesis of vinyl silicone resin:

[0105] (a) 10 kg of vinyldimethylethoxysilane was mixed with 100 kg of distilled water and stirred at room temperature for a hydrolysis reaction for 2 hours at a stirring speed of 170 r / min to obtain vinyldimethylsilanol;

[0106] (b) 20 kg of vinyltriethoxysilane was mixed with 200 kg of distilled water and stirred at room temperature for a hydrolysis reaction for 3 hours at a stirring speed of 100 r / min to obtain vinyltrisilanol;

[0107] (c) 60 kg of tetraethoxysilane was mixed with 135 kg of distilled water and stirred at room temperature for a hydrolysis reaction for 5 hours at a stirring speed of 200 r / min to obtain tetrasilanol;

[0108] (d) The obtained vinyldimethylsilanol, vinyltrisilanol, tetrasilanol, and 2.3 kg of concentrated sulfuric acid with a concentration of 98% were mixed and stirred for a polycondensation reaction for 10 hours at a stirring speed of 90 r / min, and the polycondensation reaction temperature was 80 °C to obtain vinyl silicone resin;

[0109] (3) Emulsification: 30 kg of mercaptopropyl polysiloxane, 5 kg of vinyl silicone resin, 10 kg of isodecyl alcohol polyoxyethylene ether, 54.5 kg of distilled water, and 0.5 kg of hydroxycyclohexyl phenyl ketone were mixed and emulsified by high-speed shearing to obtain the above-mentioned photocurable emulsion-type semi-permanent silicone-containing release agent. The high-speed shearing speed was 3000 r / min, and the emulsification time was 90 min.

[0110] Effect experiment

[0111] The photocurable emulsion-type semi-permanent silicone-containing release agent prepared in Example 1 was sprayed on a stainless steel plate at 85 °C. After the water evaporated, a bright and flat coating could be formed, as Figure 3 shown.

[0112] The photocurable emulsion-type semi-permanent silicone-containing release agent prepared in Example 2 was subjected to a demolding test in a certain PU tire factory in Xiamen. A complete PU tire could be obtained, and the surface was bright and free of oil stains, as Figure 4 shown.

[0113] The photocurable emulsion-type semi-permanent silicone-containing release agent prepared in Example 3 was subjected to a demolding test in a certain epoxy resin products factory in Jingdezhen. A complete epoxy resin product could be obtained without defects, as Figure 5 shown.

[0114] The photocurable emulsion-type semi-permanent silicone-containing release agent prepared in Example 1 was subjected to 2 freeze-thaw experiments. According to the stability test method of GB / T19136-2021, the heat storage condition was 52 - 56 °C / 24 h, and the emulsion stability was monitored every 3 days as a cycle. After 3 months, it was still stable, as Figure 6 shown.

[0115] The description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be obvious to those skilled in the art. The general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to these embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A preparation method of a photocurable emulsion-type semi-permanent silicone-containing mold release agent, characterized in that, It includes the following steps: (1) Preparation of mercaptopropyl polysiloxane: Mix mercaptopropyl dimethyldialkoxysilane with water and stir. A hydrolysis reaction occurs at room temperature to obtain a mercaptopropyl dimethyl dihydroxy intermediate; Mix the mercaptopropyl dimethyl dihydroxy intermediate, hexamethylcyclotrisiloxane, hexamethyldisiloxane, and a basic catalyst and stir. A polymerization reaction occurs to obtain mercaptopropyl polysiloxane; (2) Synthesis of vinyl silicone resin: (a) Mix vinyldimethylalkoxysilane with water and stir. A hydrolysis reaction occurs at room temperature to obtain vinyldimethylsilanol; (b) Mix vinyltrialkoxysilane with water and stir. A hydrolysis reaction occurs at room temperature to obtain vinyltrisilanol; (c) Mix tetraalkoxysilane with water and stir. A hydrolysis reaction occurs at room temperature to obtain tetrasilanol; (d) Mix vinyldimethylsilanol, vinyltrisilanol, tetrasilanol, and an acidic catalyst and stir. A polycondensation reaction occurs to obtain vinyl silicone resin; (3) Emulsification: Mix mercaptopropyl polysiloxane, vinyl silicone resin, an emulsifier, water, and a photoinitiator, and perform high-speed shear emulsification to obtain the photocurable emulsion-type semi-permanent silicone release agent; The mass percentages of the raw materials used in the emulsification in step (3) are as follows: mercaptopropyl polysiloxane 10 - 30%, vinyl silicone resin 5 - 20%, emulsifier 5 - 10%, water 45 - 65%, photoinitiator 0.1 - 0.5%; In step (3), the high-speed shear rotation speed is 2000 - 3000 r / min, and the emulsification time is 45 - 90 min; In step (3), the emulsifier is isodecyl polyoxyethylene ether and / or isotridecyl polyoxyethylene ether, and the photoinitiator is hydroxycyclohexyl phenyl ketone.

2. The preparation method of a photocurable emulsion-type semi-permanent silicone release agent according to claim 1, characterized in that, In step (1), the mass ratio of mercaptopropyl dimethyldialkoxysilane to water is 1:(1 - 10), and the mass ratio of mercaptopropyl dimethyldialkoxysilane, hexamethylcyclotrisiloxane, hexamethyldisiloxane, and the basic catalyst is (20 - 35):(58 - 75):(6 - 10):(0.01 - 0.05).

3. The preparation method of a photocurable emulsion-type semi-permanent silicone release agent according to claim 1, characterized in that, In step (1), the hydrolysis reaction time is 2 - 5 hours; the polymerization reaction temperature is 100 - 110 °C, and the polymerization reaction time is 6 - 12 hours.

4. The preparation method of a photocurable emulsion-type semi-permanent silicone release agent according to claim 1, wherein In step (a), the mass ratio of vinyldimethylalkoxysilane to water is 1:(1 - 10); in step (b), the mass ratio of vinyltrialkoxysilane to water is 1:(1 - 10); in step (c), the mass ratio of tetraalkoxysilane to water is 1:(1 - 10), and the mass ratio of vinyldimethylalkoxysilane, vinyltrialkoxysilane, tetraalkoxysilane, and the acidic catalyst is (4 - 10):(20 - 35):(60 - 75):(1.5 - 3).

5. The preparation method of a photocurable emulsion-type semi-permanent silicone-containing release agent according to claim 1, characterized in that, In step (a), the hydrolysis reaction time is 2 - 5 hours; in step (b), the hydrolysis reaction time is 2 - 5 hours; in step (c), the hydrolysis reaction time is 2 - 5 hours; in step (d), the polycondensation reaction temperature is 60 - 80 °C, and the polycondensation reaction time is 5 - 10 hours.

6. A photocurable emulsion-type semi-permanent silicone release agent prepared by the method according to any one of claims 1 to 5.

7. Use of the photocurable emulsion-type semi-permanent silicone release agent according to claim 6 in the demolding of PU products and epoxy resin products.

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