MQ silicone resin and its base catalytic synthesis method and MQ silicone resin-based high-adhesion silicone pressure-sensitive adhesive

Abstract

The application belongs to the field of advanced organic silicon material, and discloses an MQ silicone resin, an alkali catalytic synthesis method thereof, and an MQ silicone resin-based high-adhesion organic silicon pressure-sensitive adhesive. M unit raw materials and Q unit raw materials are added into an organic solvent, mixed, and then a mixed solution of alkali, water and a short-chain alcohol is added dropwise to perform an alkali catalytic hydrolysis condensation reaction, so as to obtain the MQ silicone resin; a silane compound containing a glycidyl ether oxypropyl can also be added into the reaction system, so as to obtain an epoxy-modified MQ silicone resin. The above resin is compounded with hydroxyl-terminated polydimethylsiloxane, vinyl polysiloxane, an organic solvent and a glycidyl ether oxypropyl silane-based oligomer to form a solvent-based main adhesive, and a platinum gold catalyst, an inhibitor and a hydrogen-containing silicone oil cross-linking agent are used to form the pressure-sensitive adhesive. After each component is mixed uniformly and coated on a PET substrate or the like, high-temperature curing is performed, and the peeling strength is as high as 500 g / 25 mm or more. The application has a simple preparation process, high peeling strength and a wide application prospect in the field of organic silicon pressure-sensitive adhesive.

Description

Technical Field

[0001] This invention belongs to the field of advanced organosilicon materials, specifically relating to an MQ silicone resin, its alkaline-catalyzed synthesis method, and an MQ silicone resin-based high-viscosity organosilicon pressure-sensitive adhesive. Background Technology

[0002] Organosilicon pressure-sensitive adhesives combine the advantages of both organic and inorganic materials, exhibiting excellent electrochemical properties, weather resistance, and corrosion resistance. They also demonstrate good adhesion to low surface energy surfaces such as silicone rubber products, resulting in a wide range of applications. Typically, organosilicon pressure-sensitive adhesives are mainly composed of polysiloxanes, MQ silicone resins, catalysts, crosslinking agents, solvents, and some additives. The polysiloxane provides the framework and curing mechanism, while the MQ silicone resin provides adhesion and strength. These two substances constitute the vast majority of the composition, excluding the solvent. Therefore, the key to organosilicon pressure-sensitive adhesives lies in the polysiloxane and MQ silicone resin.

[0003] With market development, addition-type silicone pressure-sensitive adhesives have gained widespread recognition. However, due to the limitations of existing acid-process MQ silicone resins, the degree of condensation is limited, the molecular weight is low, the tackifying and strengthening effect is limited, and a large number of silanol groups are generated. Their compatibility with polysiloxanes is often very poor, and appropriate post-treatment is required to meet the compatibility requirements. However, this is far from meeting the requirements of modern high-viscosity and high-strength silicone pressure-sensitive adhesives. Summary of the Invention

[0004] In order to overcome the shortcomings and deficiencies of the prior art, the primary objective of this invention is to provide an alkaline-catalyzed synthesis method for MQ silicone resin.

[0005] Another object of the present invention is to provide an MQ silicone resin.

[0006] Another object of the present invention is to provide an MQ silicone resin-based high-viscosity organosilicon pressure-sensitive adhesive.

[0007] This invention relates to silicone resins containing M and Q units prepared by an alkaline catalytic condensation method. This not only yields high molecular weight MQ or modified MQ silicone resins, but also exhibits good compatibility with polysiloxanes. With the modification of a small amount of glycidyl ether oxypropyl epoxy groups, the adhesion and peel strength of the thermosetting addition-type silicone pressure-sensitive adhesive tape cured on the substrate surface are significantly improved, thus completing this invention.

[0008] The objective of this invention is achieved through the following technical solution:

[0009] A base-catalyzed synthesis method for MQ silicone resin includes the following steps:

[0010] (1) Add the raw materials of unit M and unit Q to organic solvent 1, mix them evenly, then add a mixture of alkali 1, water and short-chain alcohol 1 dropwise, and heat to carry out alkali-catalyzed hydrolysis condensation reaction;

[0011] (2) After the reaction is completed, the product is concentrated under reduced pressure, filtered, the filtrate is taken and the solvent is removed, and the resulting solid is MQ silicone resin.

[0012] Preferably, the raw material for the M unit is at least one of methoxytrimethylsilane, methoxyvinyldimethylsilane, methoxyphenyldimethylsilane, or ethoxytrimethylsilane; the raw material for the Q unit is at least one of ethyl silicate or tetramethoxysilane, and tetramethoxysilane accounts for less than 50% of the total molar amount of the Q unit raw material; the molar ratio of the M unit raw material to the Q unit raw material is 0.8~1.5:1;

[0013] Preferably, the ethyl silicate comprises tetraethoxysilane or its oligomers, ethyl silicate 32 and ethyl silicate 40, wherein the tetramethoxysilane in the mixture of ethyl silicate and tetramethoxysilane does not exceed 10 wt% of the total mixture.

[0014] The alkali 1 is at least one of sodium carbonate, potassium carbonate, cesium carbonate, lithium alkoxide, sodium alkoxide, potassium alkoxide, lithium trimethylsilyl alkoxide, sodium trimethylsilyl alkoxide, potassium trimethylsilyl alkoxide, lithium hydroxide, sodium hydroxide, potassium hydroxide, cesium hydroxide, tetramethylammonium hydroxide, tetrabutylammonium hydroxide, and volatile tertiary amines, wherein the volatile tertiary amine is trimethylamine, triethylamine, dimethylpropylamine, or dimethylbutylamine, and the amount used is 50-500 ppm of the total mass of the organosilicon compound raw material;

[0015] The molar amount of water used is 30-61% of the total molar amount of alkoxy groups in the organosilicon compound raw material;

[0016] The short-chain alcohol 1 is methanol or ethanol, and its dosage is 50-150% of the total mass of water;

[0017] The organic solvent 1 is at least two of methanol, ethanol, tetrahydrofuran, propyl ether, anisole, toluene, xylene, methyl acetate, ethyl acetate, and methyl propionate, and not all of them are alcohols at the same time. The amount used is 50 to 150% of the mass of the raw material in unit Q.

[0018] Preferably, the temperature of the alkaline-catalyzed hydrolysis condensation reaction is 40~70℃, and the time is 8~48 hours.

[0019] Preferably, a silane compound containing glycidyl ether oxypropyl is added before mixing in step (1), and the final solid obtained is epoxy-modified MQ silicone resin.

[0020] Preferably, the silane compound containing glycidyl etheroxypropyl is 3-glycidyl etheroxypropyltrimethoxysilane or 3-glycidyl etheroxypropylmethyldimethoxysilane, 3-glycidyl etheroxypropyltriethoxysilane, or 3-glycidyl etheroxypropylmethyldiethoxysilane; the molar ratio of the silane compound containing glycidyl etheroxypropyl to the raw material of unit Q is 0.001~0.02:1.

[0021] Preferably, the organosilicon compound raw material includes M-unit raw material and Q-unit raw material, or includes M-unit raw material, Q-unit raw material and silane compound containing glycidyl ether oxypropyl.

[0022] Preferably, the structural formula of the glycidyl ether oxypropyl silane is as follows:

[0023] ,

[0024] Where R = CH3, OR` (R` = CH3, C2H5, H), OSi ≡;

[0025] The structural formula of the M unit in the silicone resin containing M and Q units is as follows:

[0026] ,

[0027] Where R`` = CH3, CH = CH2;

[0028] The structural formula of the Q unit is as follows:

[0029]

[0030] Wherein, R``` = C2H5, CH3, H, Si≡.

[0031] An MQ silicone resin is prepared by the method described above;

[0032] The number-average molecular weight of the MQ silicone resin is 5000~10000, and the weight-average molecular weight is 8000~25000.

[0033] A high-viscosity silicone pressure-sensitive adhesive based on MQ silicone resin, comprising the aforementioned MQ silicone resin.

[0034] Preferably, the MQ silicone resin-based high-viscosity organosilicon pressure sensor comprises, by weight, the following:

[0035] The pressure-sensitive adhesive base is 150-215 parts, preferably 150-201.2 parts;

[0036] Platinum catalyst 30~100×10 -6 share,

[0037] Inhibitor 0.2~0.6 parts,

[0038] 0.5-3 parts of hydrogen-containing silicone oil crosslinking agent;

[0039] The pressure-sensitive adhesive base comprises the following components:

[0040] MQ silicone resin 50-65 parts,

[0041] 15-25 parts of hydroxyl-terminated polydimethylsiloxane

[0042] 10-25 parts of vinyl polysiloxane

[0043] The above components total 100 portions;

[0044] Organic solvent 2 50~100 parts,

[0045] 0-1.2 parts of tackifying resin.

[0046] Preferably, the tackifying resin is a glycidyl ether oxypropyl silyl hydrolytic cocondensation oligomer, and the preparation method is as follows:

[0047] The difunctional organosilicon monomers of 3-glycidyl etheroxypropyltrimethoxysilane and / or 3-glycidyl etheroxypropylmethyldimethoxysilane, vinyltrimethoxysilane, and dimethylsilane are mixed evenly in a molar ratio of 1:0.5~1.2:0.5~4. A mixture of alkali 2, water, and short-chain alcohol 2 is added dropwise under stirring. The mixture is heated to 50~60℃ and reacted for 4~24 hours. After neutralization, the solvent and volatile substances are removed under reduced pressure. The mixture is then filtered, and the resulting liquid is the thickening resin.

[0048] Preferably, the neutralization is achieved by adding up to 10 equivalents of excess acetic acid.

[0049] The difunctional organosilicon monomer containing dimethylsilicon is a small-molecule terminal hydroxyl silicone oil with a molecular weight of less than 1000 or a dimethyldimethoxysilane.

[0050] The alkali 2 is at least one of sodium carbonate, potassium carbonate, cesium carbonate, lithium hydroxide, sodium hydroxide, potassium hydroxide, cesium hydroxide, tetramethylammonium hydroxide, and tetrabutylammonium hydroxide, and the amount used is 50 to 300 ppm of the total mass of the organosilicon compound raw material;

[0051] The molar amount of water used is 80-95% of the total molar amount of alkoxy groups in the organosilicon compound;

[0052] The short-chain alcohol 2 is methanol or ethanol, and its amount is 50-100% of the total mass of water.

[0053] Preferably, the hydroxyl-terminated polydimethylsiloxane is a double-hydroxyl-terminated polydimethylsiloxane with a number-average molecular weight of 300,000 to 1,000,000, and is preferably hydroxyl-terminated raw rubber OH-70 or hydroxyl-terminated raw rubber OH-60.

[0054] The vinyl polysiloxane is at least one of multi-terminated vinyl polysiloxane, dual-terminated vinyl polysiloxane, or end-sided vinyl polysiloxane, wherein the end-sided vinyl polysiloxane accounts for more than 80 wt% of the total vinyl polysiloxane; the multi-terminated vinyl polysiloxane is at least one of tri-terminated vinyl polydimethylsiloxane or tetra-terminated vinyl polydimethylsiloxane; the end-sided vinyl polydimethylsiloxane is a high molecular weight polydimethylsiloxane containing both end-sided and end-sided vinyl groups, with an average of 3 to 12 vinyl groups per molecule and a number-average molecular weight of 250,000 to 600,000.

[0055] Preferably, the preparation method of the multi-terminal vinyl polysiloxane is as follows:

[0056] Add 200 parts by weight of 100-200 mPa•s terminal vinyl silicone oil to a container equipped with a stirrer at room temperature, then add 0.3-0.5 parts by weight of Karstedt catalyst diluted with an inert solvent (platinum concentration of 1000 ppm). After stirring evenly, add 0.1-0.3 parts by weight of inhibitor or an inhibitor solution of the corresponding amount, and stir evenly again. Then add tetra(dimethylsiloxy)silane or alkyltri(dimethylsiloxy)silane, raise the temperature to 40°C and react for 1-2 hours, then raise the temperature to 50°C and react for 4-6 hours, and finally raise the temperature to 60°C and react for 4-6 hours. After cooling for 4-8 hours, a viscous polyvinyl dimethylsiloxane with tetra- or tri-terminal vinyl groups as the main components is obtained. The inhibitor solution is a 5-50 wt% inhibitor solution of toluene, ethyl acetate, or xylene. The alkyltris(dimethylsiloxy)silane is phenyltris(dimethylsiloxy)silane or methyl(dimethylsiloxy)silane. The molar amount of tetra(dimethylsiloxy)silane is 10-12.5% ​​of the molar amount of vinyl groups in the vinyl-terminated silicone oil, and the molar amount of alkyltris(dimethylsiloxy)silane is 15-16.7% of the molar amount of vinyl groups in the vinyl-terminated silicone oil.

[0057] The organic solvent 2 is at least one of toluene, xylene, cyclohexane, solvent oil, or ethyl acetate, methyl acetate, propyl acetate, butyl acetate, methyl propionate, ethyl propionate, and propyl propionate.

[0058] The platinum catalyst is a Karstedt catalyst with a concentration of 1000~10000ppm;

[0059] The inhibitor is at least one of 1-ethynylcyclohexanol, 2-methyl-3-butyn-2-ol or diallyl maleate.

[0060] The hydrogen-containing silicone oil crosslinking agent is dimethyl silicone oil with an active hydrogen content of 0.6~1.55wt%.

[0061] The preparation method of the main component of the pressure-sensitive adhesive is as follows: Take 50-65 parts by weight of silicone resin containing M and Q units prepared by alkaline condensation, add 50-100 parts by weight of organic solvent 1, stir and mix to dissolve, raise the oil temperature to 80℃-100℃ under reflux stirring, add 15-25 parts by weight of hydroxyl-terminated polydimethylsiloxane and 10-25 parts by weight of vinyl polysiloxane, keep warm and slowly dissolve, after 4-8 hours, obtain 150-200 parts by weight of viscous solution, add 0-1.2 parts by weight of glycidyl ether oxypropyl oligopolysiloxane tackifier, cool, and obtain 150-215 parts by weight of the corresponding pressure-sensitive adhesive main component.

[0062] The preparation method of the aforementioned silicone pressure-sensitive adhesive is as follows: the main adhesive component is mixed evenly with the platinum catalyst component, the inhibitor component and the hydrogen-containing siloxane crosslinking agent component, and then applied to the thermosetting addition-type high-viscosity silicone pressure-sensitive adhesive tape on substrates such as PET, paper-based, and BOPP.

[0063] The pressure-sensitive adhesive tape is prepared as follows: 150-2015 parts by weight of the main adhesive component are diluted with ethyl acetate to a content of 30 wt%, and platinum is added sequentially in amounts of 30-100 × 10⁻⁶. -6 Mix 0.2-0.6 parts by weight of platinum catalyst and inhibitor, stir well, then add 0.5-3 parts by weight of hydrogen-containing silicone oil crosslinking agent, stir for 5 minutes, coat onto a 50-micron PET film, level the coating, wait for the solvent to evaporate in 3-5 minutes, place in an oven at 150-155℃ to cure for 3-2 minutes, remove, cool, and apply fluorine release protective film to obtain a pressure-sensitive protective tape with high adhesion and high peel strength to silicone release film.

[0064] The silicone release film is prepared as follows: 20 parts by weight of multi-terminal vinyl polydimethylsiloxane are taken at room temperature, and 0.5-1 parts by weight of 1000 ppm Karstedt catalyst and 0.02-0.05 parts by weight of inhibitor or inhibitor solution of corresponding content are added sequentially. The mixture is stirred evenly, and 3-10 parts by weight of 10 wt% ethyl acetate solution of hydrogen-containing silicone oil crosslinking agent are added. After stirring evenly, the mixture is coated on a 50-micron thick PET film, smoothed with a coater, dried at room temperature, and cured in an oven at 130-150℃ for 3-1 min. The film is then removed, cooled, and the silicone release film is obtained.

[0065] This invention utilizes trace amounts of alkali catalysis to introduce Q units containing polyalkoxy groups and M units containing monoalkoxy groups into a small amount of silane containing T units containing trialkoxy groups or D units containing dialkoxy groups. The amount of water added is controlled (the molar amount of water is less than 61% of the total molar number of alkoxy groups in the silane raw material). Through hydrolytic co-condensation under the protection of an alcohol solvent, the hydrolysis rate of the alkoxy groups is controlled, resulting in high molecular weight MQ or modified MQ silicone resins containing Q and M units with good end-capping effect and good solvent solubility. Simultaneously, no wastewater is generated, and the solvent can be recycled. Experiments show that this silicone resin has good compatibility with polysiloxanes. Further, the introduction of a small amount of glycidyl ether oxypropyl chains or the physical mixing of a small amount of glycidyl ether oxypropyl oligomers significantly enhances the reinforcing effect of the thermosetting addition-type silicone pressure-sensitive adhesive. Experiments show that the silicone resin containing M and Q units prepared by the alkali-catalyzed method of this invention has a high molecular weight, with a number average molecular weight of over 5000 and a weight average molecular weight as high as 9000-15000. It also exhibits good compatibility with polydimethylsiloxane and maintains epoxy group stability even with a low amount of glycidyl ether oxypropylsilane. The silicone resin containing M and Q units prepared by the alkali condensation method, with an effective content of 50-65 wt%, demonstrates high peel strength (over 500 g / 25 mm) at a coating thickness of 8-10 micrometers. Especially when the amount of glycidyl ether oxypropyl oligomeric siloxane tackifier added is 0.5 wt%-1 wt%, the peel strength increases significantly, reaching over 650 g / 25 mm, and in some cases even exceeding 1000 g / 25 mm.

[0066] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0067] (1) The MQ or modified MQ silicone resin containing M and Q units prepared by the present invention is not only simple in process, but also generates no wastewater, the solvent is easy to recycle and reuse, and the epoxy groups can exist stably.

[0068] (2) The MQ or modified MQ silicone resin prepared by the alkali catalytic condensation method of the present invention has a large molecular weight, with a number average molecular weight of over 5000 and a weight average molecular weight of up to 9000~15000. It has good solubility, good compatibility with polysiloxane, and significant thickening and strengthening effects.

[0069] (3) When the pressure-sensitive adhesive is coated on materials such as PET, after addition-type thermosetting, the peel strength is as high as 500 g / 25 mm or more; the peel strength is significantly increased after a small amount of glycidyl ether oxypropyl modification, with a peel strength as high as 650 g / 25 mm or more, and some even as high as 1000 g / 25 mm or more, which is superior to MQ silicone resin prepared by traditional acid method and water glass method. Attached Figure Description

[0070] Figure 1 ,2 The HNMR (CDCl3) values ​​are those of the MQ silicone resin containing glycidyl ether oxypropyl prepared in Examples 1-1 and 1-2, respectively.

[0071] Figure 3 , 4 5 are the HNMR (CDCl3) results of high molecular weight MQ silicone resin prepared by alkaline catalytic condensation in Examples 1-3, 1-4, and 1-5, respectively.

[0072] Figure 6 The HNMR (CDCl3) of the MQ silicone resin containing glycidyl ether oxypropyl prepared in Examples 1-6.

[0073] Figure 7 , Figure 8 HNMR (CDCl3) of the glycidyl ether oxypropyl silicone oligomeric siloxane tackifiers prepared in Examples 2-1 and 2-2. Figure 9 , Figure 10 The HNMR (CDCl3) of the multi-terminal vinyl polysiloxanes prepared in Examples 3-1 and 3-2.

[0074] Figure 11 , Figure 12 The GPC molecular weight distribution diagrams are shown for the MQ silicone resins containing glycidyl ether oxypropyl prepared in Examples 1-1 and 1-2, respectively.

[0075] Figure 13 These are the FTIR infrared spectra of the MQ silicone resins prepared in Examples 1-1 and 1-3 (potassium bromide tableting method). Detailed Implementation

[0076] The present invention will be further described in detail below with reference to the embodiments and accompanying drawings. However, the implementation of the present invention is not limited thereto. For process parameters not specifically noted, conventional techniques can be referred to.

[0077] Example 1: Preparation of high molecular weight MQ silicone resin solid

[0078] Example 1-1: Glycidyl ether oxypropyl methyl MQ silicone resin EMQ1

[0079] In a 250 mL three-necked flask equipped with a stirring and reflux dropping device, 62.5 g of tetraethoxysilane (molecular weight 208.3, SiQ2 content 28.8 wt%) (0.3 mol SiQ2, 1.2 mol OEt), 37.44 g of methoxytrimethylsilane (0.36 mol, M / Q molar ratio 1.2), 0.47 g of 3-glycidyl etheroxypropyltrimethylsilane, 30 g of tetrahydrofuran, and 20 g of methanol were mixed thoroughly at room temperature. A mixture of 49 mg potassium carbonate, 13.32 g (0.74 mol) of water, and 10 g of methanol was added dropwise with stirring, completing the addition within 15 min. The mixture was heated to 60 °C and reacted for 45 h. The mixture was then concentrated under reduced pressure at 70 °C, centrifuged, and the solvent was removed from the supernatant to obtain solid EMQ4 silicone resin. Samples were taken and analyzed by nuclear magnetic resonance (HNMR) (CDCl3), infrared FTIR (potassium bromide pellet method), and GPC (THF solvent) to obtain... Figure 1 The HNMR shown Figure 11 The GPC distribution map shown below Figure 13 The FTIR (EMQ caliber) and GPC measurements show that the number-average molecular weight is 5772, the weight-average molecular weight is 9384, and the molecular weight distribution index (PDI) is 1.63, indicating that the MQ silicone resin synthesized in this embodiment has a high molecular weight and a narrow molecular weight distribution.

[0080] Example 1-2: Glycidyl ether oxypropyl methyl MQ silicone resin EMQ2

[0081] In a 250 mL three-necked flask equipped with a stirring and reflux dropping device, 62.5 g (0.3 mol) of tetraethoxysilane (molecular weight 208.3, SiQ2 content 28.8 wt%), 28.1 g (0.27 mol) of methoxytrimethylsilane (M / Q molar ratio 0.9), 0.66 g of 3-glycidyl etheroxypropylmethyldimethoxysilane, 50 g of xylene, and 30 g of methanol were mixed thoroughly at room temperature. A mixture of 10 mg lithium hydroxide, 12.6 g (0.75 mol) of water, and 20 g of methanol was added dropwise over 10 min with stirring. The mixture was then heated to 60 °C and reacted for 36 h. The mixture was concentrated under reduced pressure at 80 °C, filtered, and the solvent was removed from the filtrate to obtain solid EMQ2 silicone resin. Samples were taken and analyzed by nuclear magnetic resonance (NMR) (CDCl3) and GPC (THF solvent). Figure 2 The HNMR and Figure 12 The GPC distribution map shown indicates that its number-average molecular weight is 6564, its weight-average molecular weight is 11582, and its molecular weight distribution index (PDI) is 1.76.

[0082] Example 1-3: Methyl MQ silicone resin MQ3

[0083] In a 500 mL three-necked flask equipped with a stirring and reflux dropping device, 100 g of 40% tetraethyl orthosilicate (SiQ2 content 40 wt%) (SiQ2 content 2 / 3 mol), 99.8 g of methoxytrimethylsilane (0.96 mol, M / Q molar ratio 1.44), 60 g of toluene, and 50 g of methanol were mixed thoroughly at room temperature. A mixture of 60 mg sodium carbonate, 16.38 g of water (0.91 mol), and 15 g of methanol was added dropwise over 20 min with stirring. The mixture was then heated to 40 °C and stirred for 8 h, followed by further heating to 60 °C and reacting for 16 h. The mixture was concentrated under reduced pressure at 70 °C, centrifuged, and the solvent was removed from the supernatant to obtain solid MQ3 silicone resin. Samples were taken and analyzed by nuclear magnetic resonance (NMR) (CDCl3), infrared FTIR (potassium bromide pellet method), and GPC (THF solvent method), yielding the desired results. Figure 3 The HNMR shown Figure 13 The FTIR (MQ marking) shown is at 2960cm. -1 The absorption peak of its organic saturated CH is clearly visible nearby. GPC test shows that its number average molecular weight is 6893, its weight average molecular weight is 14985, and its molecular weight distribution index (PDI) is 2.17.

[0084] Example 1-4: Methyl MQ silicone resin MQ4

[0085] In a 500 mL three-necked flask equipped with a stirring and reflux dropping device, 104.15 g (0.5 mol) of tetraethoxysilane (molecular weight 208.3, SiQ2 content 28.8 wt%), 59.0 g (0.5 mol) of ethoxytrimethylsilane (M / Q molar ratio 1.0), 30 g of tetrahydrofuran, and 10 g of methanol were mixed thoroughly at room temperature. A mixture of 8.5 mg sodium hydroxide, 27 g (1.5 mol) of water, and 20 g of methanol was added dropwise over 15 min with stirring. The mixture was then heated to 40 °C and reacted for 8 h, followed by 70 °C and reacted for 16 h. The mixture was concentrated under reduced pressure at 70 °C, filtered, and the solvent was removed from the filtrate to obtain solid MQ4 silicone resin. Samples were taken and analyzed by nuclear magnetic resonance (NMR) (CDCl3) and GPC (THF solvent) to obtain... Figure 4 The HNMR and GPC tests shown indicate that its number-average molecular weight is 5836, its weight-average molecular weight is 9872, and its molecular weight distribution index (PDI) is 1.69.

[0086] Example 1-5: Methyl MQ silicone resin MQ5

[0087] In a 500 mL three-necked flask equipped with a stirring and reflux dropping device, 104.15 g (0.5 mol) of tetraethoxysilane (molecular weight 208.3), 45.76 g (0.44 mol) of methoxytrimethylsilane (M / Q molar ratio 0.88), 70 g of xylene, and 50 g of ethanol were mixed thoroughly at room temperature. A mixture of 15 mg tetramethylammonium hydroxide, 30 mg triethylamine, 21.96 g (1.22 mol) of water, and 20 g of methanol was added dropwise over 5 min with stirring. The mixture was then heated to 60 °C and reacted for 18 h. The mixture was concentrated under reduced pressure at 80 °C, filtered, and the solvent was removed from the filtrate to obtain solid MQ5 silicone resin. Samples were taken and analyzed by nuclear magnetic resonance (NMR) (CDCl3) and GPC (THF solvent) to obtain... Figure 5 The HNMR and GPC measurements shown indicate that its number-average molecular weight is 6759, its weight-average molecular weight is 12458, and its molecular weight distribution index (PDI) is 1.84.

[0088] Figures 3-5 The chemical shift of H on silymine groups with significant M groups is observed in the 0–0.1 ppm range; the chemical shift of methylene H on unhydrolyzed Si-OCH2CH3 on the Q unit is observed around 3.7 ppm; and the chemical shift of methyl H on unhydrolyzed Si-OCH2CH3 is observed around 1.1 ppm.

[0089] Examples 1-6: Vinylepoxy MQ (YEMQ6)

[0090] In a 250 mL three-necked flask equipped with a stirring and reflux dropping device, 62.49 g (0.3 mol) of tetraethoxysilane, 31.2 g (0.3 mol) of methoxytrimethylsilane (M / Q molar ratio 1.0), 0.40 g of 3-glycidyl etheroxypropyltrimethylsilane, 0.30 g of vinyltrimethoxysilane, 30 g of tetrahydrofuran, and 20 g of methanol were mixed thoroughly at room temperature. A mixture of 37.8 mg potassium carbonate, 13.5 g (0.75 mol) of water, and 15 g of methanol was added dropwise over 15 min with stirring. The mixture was then heated to 60 °C and reacted for 48 h. The mixture was concentrated under reduced pressure at 70 °C, centrifuged, and the solvent was removed from the supernatant to obtain solid YEMQ6 silicone resin. Samples were taken and analyzed by nuclear magnetic resonance (NMR) (CDCl3) and GPC (THF solvent) to obtain... Figure 6 The HNMR and GPC measurements shown indicate that its number-average molecular weight is 6011, its weight-average molecular weight is 10475, and its molecular weight distribution index (PDI) is 1.74.

[0091] Figure 1 , Figure 2 and Figure 6 The chemical shifts of the three H atoms in the epoxy group are clearly visible between 2.5 and 3.2 ppm, indicating that the epoxy groups of this invention are stable under alkaline catalytic hydrolysis and condensation conditions. Figure 6 The chemical shifts of H on the vinyl group in the silyl vinyl group are clearly visible at 5.8–6.1 ppm. In addition, there are significant chemical shifts of H on the silyl methyl group of the M group at 0–0.1 ppm. Around 3.7 ppm, there is a chemical shift of the methylene H on the unhydrolyzed Si-OCH2CH3 on the Q unit. Around 1.1 ppm, there is a chemical shift of the methyl H on the Si-OCH2CH3.

[0092] Example 1-7: Methyl MQ silicone resin MQ7

[0093] In a 250 mL three-necked flask equipped with a stirring and reflux dropping device, 62.49 g (0.3 mol) of tetraethoxysilane, 4.56 g (0.03 mol) of tetramethoxysilane, 37.75 g (0.363 mol) of methoxytrimethylsilane (M / Q molar ratio 1.1), 50 g of xylene, and 30 g of ethanol were mixed thoroughly at room temperature. A mixture of 5 mg potassium hydroxide, 10 mg tripropylamine, 13.5 g (0.75 mol) of water, and 20 g of methanol was added dropwise over 15 min with stirring. The mixture was then heated to 40 °C and reacted for 4 h, followed by 60 °C and reacted for 20 h. The mixture was concentrated under reduced pressure at 80 °C, filtered, and the solvent was removed from the filtrate to obtain solid MQ7 silicone resin. A sample was taken and subjected to GPC (THF solvent) analysis, revealing a number-average molecular weight of 7280, a weight-average molecular weight of 14166, and a molecular weight distribution index (PDI) of 1.95.

[0094] Example 2: Preparation of glycidyl ether oxypropyl oligosiloxane tackifier

[0095] Example 2-1: In a 250 mL three-necked flask equipped with a stirring and reflux dropping device, 48.0 g (0.4 mol) of dimethyldimethoxysilane, 14.8 g (0.1 mol) of vinyltrimethoxysilane, and 23.6 g (0.1 mol) of 3-glycidyl etheroxypropyltrimethoxysilane were mixed thoroughly at room temperature. A mixture of 13 mg sodium hydroxide, 22.05 g (1.225 mol) water, and 15 g methanol was added dropwise over 10 minutes. The mixture was then heated to 50 °C and reacted for 4 hours. 30 mg of acetic acid was then added, and after 10 minutes, the solvent was removed under reduced pressure at 70 °C. The mixture was filtered to obtain a liquid thickening resin K60. A sample was taken and analyzed by nuclear magnetic resonance (NMR) (CDCl3). Figure 7 The HNMR spectrum is shown.

[0096] Example 2-2: In a 250 mL three-necked flask equipped with a stirring and reflux dropping device, 36.0 g (0.3 mol) of dimethyldimethoxysilane, 11.84 g (0.08 mol) of vinyltrimethoxysilane, and 22.0 g (0.1 mol) of 3-glycidyl etheroxypropylmethyldimethoxysilane were mixed thoroughly at room temperature. A mixture of 21 mg potassium carbonate, 16.85 g (0.936 mol) water, and 16 g ethanol was added dropwise over 5 minutes. The mixture was then heated to 60 °C and reacted for 24 hours. 30 mg acetic acid was then added, and after 10 minutes, the solvent was removed under reduced pressure at 80 °C. The mixture was filtered to obtain a liquid thickening resin K61. A sample was taken and analyzed by nuclear magnetic resonance (NMR) (CDCl3). Figure 8 The HNMR spectrum is shown.

[0097] Figure 7 and Figure 8 In the range of 2.5 to 3.2 ppm, the chemical shifts of the three H atoms in the epoxy group are clearly visible; in the range of 5.8 to 6.1 ppm, the chemical shifts of the H atoms on the vinyl group in the silyl group are clearly visible; and in the range of 0 ppm, the chemical shifts of the H atoms on the silyl group are clearly visible.

[0098] Example 3: Preparation of multi-terminated vinyl polysiloxanes

[0099] Example 3-1: In a 250 mL three-necked flask equipped with a stirrer, 200 g of vinyl-terminated silicone oil (100 mPa•s, vinyl content 1.0 wt%, i.e., 0.037 mol / 100 g) was added at room temperature. 0.5 g of Karstedt catalyst (platinum concentration 1000 ppm) diluted in toluene was added, and the mixture was stirred until homogeneous. Then, 0.8 g of a 20 wt% toluene solution of 2-methyl-3-butyn-2-ol was added and stirred until homogeneous. Under stirring, 2.53 g of tetra(dimethylsiloxy)silane was added. The mixture was heated to 40 °C and reacted for 1 hour, then to 50 °C and reacted for 4 hours, and finally to 60 °C and reacted for 8 hours. After cooling, polydimethylsiloxane V4PDMS, predominantly tetravinyl-terminated, was obtained. Sampling analysis showed a viscosity of 1200 mPa•s at 25 °C and a vinyl content of 0.0222 mol / 100 g. Nuclear magnetic resonance (NMR) analysis (CDCl3) yielded... Figure 9 The HNMR spectrum is shown.

[0100] Example 3-2: 200 g of vinyl-terminated silicone oil (100 mPa•s, vinyl content 1.0 wt%) was added to a 250 mL three-necked flask containing a stirrer at room temperature. 0.5 g of Karstedt catalyst (platinum concentration 1000 ppm) diluted in toluene was added, and the mixture was stirred until homogeneous. Then, 0.5 g of a 20 wt% toluene solution of 2-methyl-3-butyn-2-ol was added and stirred until homogeneous. 4.03 g of phenyltris(dimethylsiloxy)silane was added while stirring. The mixture was heated to 40 °C and reacted for 1 hour, then to 50 °C and reacted for 4 hours, and finally to 60 °C and reacted for 8 hours. After cooling, three vinyl-terminated polysiloxanes, V3PDMS, were obtained. Sampling analysis showed a viscosity of 2250 mPa•s at 25 °C and a vinyl content of 0.0185 mol / 100 g. Nuclear magnetic resonance (NMR) analysis (CDCl3) showed... Figure 10 The HNMR spectrum is shown.

[0101] Figure 9 and Figure 10 In the range of 5.7 to 6.2 ppm, the chemical shift of H on the vinyl group in dimethylsilyl vinyl is clearly visible, and near 0 ppm, the chemical shift of H on the silyl methyl group is abundant.

[0102] Example 3-3: Preparation of silicone release film with low peel strength

[0103] Take 20g of V4PDMS prepared in Example 3-1 at room temperature, add 0.6g of 1000ppm Karstedt catalyst and 0.6g of 5wt% ethyl acetate solution of 2-methyl-3-butyn-2-ol and stir until homogeneous. Add 5.55g of 10wt% ethyl acetate solution of hydrogen-containing silicone oil (hydrogen content of 1.2% in silicone oil), stir until homogeneous, coat it on a 50-micron thick PET film, smooth it with a No. 0 coater, air dry at room temperature, cure it in an oven at 130℃ for 3min, remove it, cool it to obtain organosilicon release low-peel film 1.

[0104] Take 20g of V3PDMS prepared in Example 3-1 at room temperature, add 0.6g of 1000ppm Karstedt catalyst and 0.6g of 5wt% ethyl acetate solution of 2-methyl-3-butyn-2-ol and stir until homogeneous. Add 4.63g of 10wt% ethyl acetate solution of hydrogen-containing silicone oil (hydrogen content of 1.2% in silicone oil), stir until homogeneous, coat it on a 50-micron thick PET film, smooth it with a No. 0 coater, air dry at room temperature, cure it in an oven at 130℃ for 3 minutes, remove it, cool it, and obtain organosilicon release low-peel film 2.

[0105] Example 5: Preparation of silicone pressure-sensitive adhesive base and tape and its 180° peel force test on silicone release film.

[0106] Examples 5-1 and 5-2:

[0107] (1) According to the composition ratio of the pressure-sensitive adhesive main adhesive shown in Table 1, the total amount of MQ silicone resin, hydroxyl raw rubber and vinyl polydimethylsiloxane is 100g. After mixing and dissolving 50g of EMQ1 silicone resin prepared in Example 1-1 with 100g of organic solvent toluene (T), the oil temperature was raised to 100℃ under reflux stirring, and 25g of hydroxyl raw rubber OH-70 (700,000 molecular weight hydroxyl-terminated polydimethylsiloxane) and 25g of vinyl polydimethylsiloxane V53 (500,000 molecular weight vinyl raw rubber, vinyl content of 0.03wt%, and an average of 5.56 vinyl molecules per polydimethylsiloxane molecule) were added. The mixture was kept warm and slowly dissolved. After 8h, 0g or 0.5g of tackifying resin K60 prepared in Example 2-1 was added, and the mixture was stirred evenly and then cooled to obtain 200g and 200.5g of the corresponding pressure-sensitive adhesive main adhesive, respectively.

[0108] (2) Dilute the main adhesive with ethyl acetate to 30wt%, add 1g of 5000ppm Karstedt catalyst and 0.3g of inhibitor 1-ethynylcyclohexanol in sequence and stir evenly. Then add 0.85g of hydrogen-containing silicone oil (hydrogen content of 1.2wt%) crosslinking agent and stir for 5 minutes. Coat it on a 50-micron PET film and scrape it once with a 30-micron wire rod (coating thickness of 8~10 microns). After the solvent evaporates, place it in an oven at 155℃ for 2 minutes to cure. Take it out, cool it, apply a fluorine release protective film, place it in an oven at 70℃ for 20 hours to mature, cool it, peel off the fluorine release protective film, and then apply the silicone release low-peel film prepared in Example 4. Test its 180° peel strength according to the test method of GB / T 2792-1998 and list the results in Table 1.

[0109] Examples 5-3, 5-4, 5-18, 5-19, 5-20, 5-21, 5-22, 5-23:

[0110] (1) According to the composition ratio of the pressure-sensitive adhesive main adhesive shown in Table 1, the total amount of MQ silicone resin, hydroxyl raw rubber and vinyl polydimethylsiloxane is 100g. After stirring and dissolving 60g of the corresponding MQ silicone resin prepared in Example 1 with 60g of organic solvent toluene, the oil temperature is raised to 100℃ under reflux stirring, 20g of hydroxyl raw rubber OH-70 and 20g of vinyl polydimethylsiloxane V53 are added, and the mixture is kept warm and slowly dissolved. After 6h, 0~1g of the tackifying resin K61 prepared in Example 2-2 is added, stirred evenly and cooled to obtain 160~161g of the corresponding pressure-sensitive adhesive main adhesive.

[0111] (2) Dilute the main adhesive with ethyl acetate to 30wt%, add 1g of 5000ppm Karstedt catalyst and 0.3g of inhibitor 1-ethynylcyclohexanol in sequence and stir evenly. Then add 0.85g of hydrogen-containing silicone oil (hydrogen content of 1.2wt%) crosslinking agent and stir for 5 minutes. Coat it on a 50-micron PET film and scrape it once with a 30-micron wire rod (coating thickness of 8~10 microns). After the solvent evaporates, place it in an oven at 155℃ for 2 minutes to cure. Take it out, cool it, apply a fluorine release protective film, place it in an oven at 70℃ for 20 hours to mature, cool it, peel off the fluorine release protective film, and then apply the silicone release low-peel film prepared in Example 4. Test its 180° peel strength according to the test method of GB / T 2792-1998 and list the results in Table 1.

[0112] Examples 5-5, 5-6, 5-9, 5-10, 5-11:

[0113] (1) According to the composition ratio of the pressure-sensitive adhesive main adhesive shown in Table 1, the total amount of MQ silicone resin, hydroxyl raw rubber and vinyl polydimethylsiloxane is 100g. After stirring and dissolving 50g of the corresponding MQ silicone resin prepared in Example 1 with 100g of organic solvent ethyl acetate (EA), the oil temperature is raised to 80°C under reflux stirring, 25g of hydroxyl raw rubber OH-70 and 25g of vinyl polydimethylsiloxane V53 are added, and the mixture is kept warm and slowly dissolved. After 8h, 0~1g of the tackifier K60 or K61 prepared in Examples 2-1 and 2-2 is added, stirred evenly and cooled to obtain 200~201g of the corresponding pressure-sensitive adhesive main adhesive.

[0114] (2) Dilute the main adhesive with ethyl acetate to 30wt%, add 1g of 5000ppm Karstedt catalyst and 0.3g of inhibitor 1-ethynylcyclohexanol in sequence and stir evenly. Then add 0.85g of hydrogen-containing silicone oil (hydrogen content of 1.2wt%) crosslinking agent and stir for 5 minutes. Coat it on a 50-micron PET film and scrape it once with a 30-micron wire rod (coating thickness of 8~10 microns). After the solvent evaporates, place it in an oven at 155℃ for 2 minutes to cure. Take it out, cool it, apply a fluorine release protective film, place it in an oven at 70℃ for 20 hours to mature, cool it, peel off the fluorine release protective film, and then apply the silicone release low-peel film prepared in Example 4. Test its 180° peel strength according to the test method of GB / T 2792-1998 and list the results in Table 1.

[0115] Examples 5-7, 5-8, 5-14, 5-15:

[0116] (1) According to the composition ratio of the pressure-sensitive adhesive main adhesive shown in Table 1, the total amount of MQ silicone resin, hydroxyl raw rubber and vinyl polydimethylsiloxane is 100g. After stirring and dissolving 60g of the corresponding MQ silicone resin prepared in Example 1 with 60g of organic solvent ethyl acetate, the oil temperature is raised to 80°C under reflux stirring, 20g of hydroxyl raw rubber OH-70 and 18~20g of vinyl polydimethylsiloxane V53 and 0~2g of multi-terminal vinyl polydimethylsiloxane prepared in Example 3 are added, and the mixture is kept warm and slowly dissolved. After 6h, 0~1g of the tackifier K61 prepared in Example 2-2 is added, and the mixture is stirred evenly and then cooled to obtain 160~161g of the corresponding pressure-sensitive adhesive main adhesive.

[0117] (2) Dilute the main adhesive with ethyl acetate to 30wt%, add 1g of 5000ppm Karstedt catalyst and 0.3g of inhibitor 1-ethynylcyclohexanol in sequence and stir evenly. Then add 0.85g of hydrogen-containing silicone oil (hydrogen content of 1.2wt%) crosslinking agent and stir for 5 minutes. Coat it on a 50-micron PET film and scrape it once with a 30-micron wire rod (coating thickness of 8~10 microns). After the solvent evaporates, place it in an oven at 155℃ for 2 minutes to cure. Take it out, cool it, apply a fluorine release protective film, place it in an oven at 70℃ for 20 hours to mature, cool it, peel off the fluorine release protective film, and then apply the silicone release low-peel film prepared in Example 4. Test its 180° peel strength according to the test method of GB / T 2792-1998 and list the results in Table 1.

[0118] Examples 5-12 and 5-13:

[0119] (1) According to the composition ratio of the pressure-sensitive adhesive main adhesive shown in Table 1, the total amount of MQ silicone resin, hydroxyl raw rubber and vinyl polydimethylsiloxane is 100g. After stirring and dissolving 60g of the corresponding MQ4 silicone resin prepared in Example 1 with 60g of organic solvent ethyl acetate, the oil temperature is raised to 80°C under reflux stirring, 20g of hydroxyl raw rubber OH-60 (600,000 molecular weight hydroxyl-terminated polydimethylsiloxane) and 20g of vinyl polydimethylsiloxane V53 are added, and the mixture is kept warm and slowly dissolved. After 5h, 0~1g of the tackifier K61 prepared in Example 2-2 is added, and the mixture is stirred evenly and then cooled to obtain 160~161g of the corresponding pressure-sensitive adhesive main adhesive.

[0120] (2) Dilute the main adhesive with ethyl acetate to 30wt%, add 1g of 5000ppm Karstedt catalyst and 0.3g of inhibitor 1-ethynylcyclohexanol in sequence and stir evenly. Then add 0.85g of hydrogen-containing silicone oil (hydrogen content of 1.2wt%) crosslinking agent and stir for 5 minutes. Coat it on a 50-micron PET film and scrape it once with a 30-micron wire rod (coating thickness of 8~10 microns). After the solvent evaporates, place it in an oven at 155℃ for 2 minutes to cure. Take it out, cool it, apply a fluorine release protective film, place it in an oven at 70℃ for 20 hours to mature, cool it, peel off the fluorine release protective film, and then apply the silicone release low-peel film prepared in Example 4. Test its 180° peel strength according to the test method of GB / T 2792-1998 and list the results in Table 1.

[0121] Examples 5-16 and 5-17:

[0122] (1) According to the composition ratio of the pressure-sensitive adhesive main adhesive shown in Table 1, the total amount of MQ silicone resin, hydroxyl raw rubber and vinyl polydimethylsiloxane is 100g. After stirring and dissolving 65g of the corresponding MQ4 silicone resin prepared in Example 1 with 60g of organic solvent ethyl acetate, the oil temperature is raised to 80°C under reflux stirring, and 15g of hydroxyl raw rubber OH-70 and 10g of vinyl polydimethylsiloxane V53 and 10g of V65 (vinyl raw rubber with a molecular weight of 600,000, vinyl content of 0.05wt%, and an average of 11.1 vinyl molecules per polydimethylsiloxane molecule) are added. The mixture is kept warm and slowly dissolved. After 4h, 0~1g of the tackifier K61 prepared in Example 2-2 is added, and the mixture is stirred evenly and then cooled to obtain 160~161g of the corresponding pressure-sensitive adhesive main adhesive.

[0123] (2) Dilute the main adhesive with ethyl acetate to 30wt%, add 1g of 5000ppm Karstedt catalyst and 0.3g of inhibitor 1-ethynylcyclohexanol in sequence and stir evenly. Then add 0.85g of hydrogen-containing silicone oil (hydrogen content of 1.2wt%) crosslinking agent and stir for 5 minutes. Coat it on a 50-micron PET film and scrape it once with a 30-micron wire rod (coating thickness of 8~10 microns). After the solvent evaporates, place it in an oven at 155℃ for 2 minutes to cure. Take it out, cool it, apply a fluorine release protective film, place it in an oven at 70℃ for 20 hours to mature, cool it, peel off the fluorine release protective film, and then apply the silicone release low-peel film prepared in Example 4. Test its 180° peel strength according to the test method of GB / T 2792-1998 and list the results in Table 1.

[0124] Comparative Examples 1-3:

[0125] (1) Take 60g of commercially available strong acid catalytic hydrolysis of ethyl silicate MQ silicone resin MQ803 (M / Q=0.70, number average molecular weight 2170, weight average molecular weight 3856), add 60g of toluene, stir to dissolve, raise the oil temperature to 100℃ under reflux stirring, add 20g of OH70 and 20g of V53, keep warm and slowly dissolve, after 8h, add 0, 0.5 and 1.0g of the tackifier K61 prepared in Example 2-2 respectively, cool, and obtain the corresponding pressure-sensitive adhesive main adhesive 160, 160.5 and 161g;

[0126] (2) Dilute the above main adhesive with ethyl acetate to 30wt%, add 1g of 5000ppm Karstedt catalyst and 0.3g of inhibitor 1-ethynylcyclohexanol and stir evenly, then add g of hydrogen-containing silicone oil (hydrogen content of 1.2wt%) crosslinking agent, stir for 5 minutes, coat it on a 50-micron PET film and scrape it once with a 30-micron wire rod. After the solvent evaporates, place it in an oven at 155℃ for 2 minutes to cure, take it out, cool it, apply a fluorine release protective film, place it in an oven at 70℃ for 20 hours to mature, cool it, peel off the fluorine release protective film, and then apply the silicone release low-peel film prepared in Examples 3-3 respectively. Test its 180° peel strength according to the test method of GB / T 2792-1998 and list the results in Table 1.

[0127] Comparative Example 4: 60g of commercially available MQ silicone resin (M / Q=0.65, number-average molecular weight 1360, weight-average molecular weight 2831) produced by the strong acid catalytic water glass method was added, along with 60g of toluene. The mixture was stirred and dissolved, and the oil temperature was raised to 100℃ under reflux stirring. 20g of OH70 and 20g of V53 were added, and the mixture was kept at this temperature for slow dissolution. After 8 hours, the mixture was cooled, resulting in a turbid mixture with obvious stratification. This indicates that the MQ resin has very poor compatibility with polysiloxanes, and the desired main adhesive cannot be obtained.

[0128] Spectral analysis shows that the MQ silicone resin prepared by the alkali-catalyzed method of this invention has a high molecular weight, with a number average molecular weight of over 5000 and a weight average molecular weight as high as 9000-15000. It also exhibits good compatibility with polydimethylsiloxane and maintains epoxy group stability even with a low amount of glycidyl ether oxypropylsilane. Table 1 shows that within the effective content range of 50-65 wt% of the M and Q units in the pressure-sensitive adhesive base, both pure MQ silicone resin and MQ silicone resin EMQ modified with glycidyl ether oxypropyl exhibit very high peel strength (over 500 g / 25 mm) at a coating thickness of 8-10 micrometers. Especially when the total amount of glycidyl ether oxypropyl oligomeric siloxane tackifier in MQ silicone resin, vinyl polysiloxane, and hydroxyl raw rubber is 0.5 wt%-1 wt%, the peel strength increases significantly, reaching over 650 g / 25 mm, and in some cases even exceeding 1000 g / 25 mm. MQ silicone resins prepared using the traditional acid method and the water glass method often exhibit turbidity and stratification during the preparation of the main adhesive due to severe compatibility issues. MQ silicone resins prepared using the silicate ester method have a lower molecular weight, resulting in a peel strength of less than 70g for the pressure-sensitive adhesive. Although glycidyl ether oxypropyl oligomeric siloxane tackifiers somewhat increase the peel strength, it remains below 200g. Therefore, modifying the alkali condensation method-containing silicone resin with a small amount of glycidyl ether oxypropyl by modifying it with M and Q units, when the amount of this silicone resin is in the range of 50-65 wt%, can yield a high-adhesion silicone pressure-sensitive adhesive with a peel strength exceeding 500g at a relatively low coating thickness.

[0129] Table 1: 180° peel strength of pressure-sensitive adhesive to silicone release film

[0130]

[0131] Example 6: 180° peel strength test of silicone release film

[0132] The release films prepared in Examples 3-3 above were sampled and attached to the release films with TESA7475 standard tape to make samples (25mm wide and 12cm long). A 2kg cylindrical steel pressure roller (GB / T2792-2014) was placed on each sample and placed at room temperature and 70℃ for 20h. The sample was then removed and the pressure roller was removed. After being placed at room temperature for 4h, the 180° peel force of the release films before aging (room temperature) and after aging (70℃) was tested. The residual adhesion rate was determined according to GB / T25256-2010 "Test Method for 180° Peel Force and Residual Adhesion Rate of Release Film for Optical Functional Films" using B31 standard adhesive. After aging at 70℃ and 2 kg pressure for 20 h, the adhesive was removed, the pressure block was removed, and the film was left at room temperature for 4 h. The percentage of the adhesive strength of the B31 standard tape after peeling from the release film to the original adhesive strength of the tape before contact with the release film was measured. The closer the percentage is to 100%, the better the silicone oil curing, the higher the cohesive strength, and the less silicone transfer. The test results are listed in Table 2.

[0133] Table 2: Test results of low peel strength and residual adhesion at 180° peel angle

[0134]

[0135] As can be seen from the test results in Table 2, the silicone release films prepared by this invention all have low peel strength, little change before and after aging, and residual adhesion rate of over 85%, all exhibiting good stability.

[0136] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A method for the alkaline-catalyzed synthesis of MQ silicone resin, characterized in that, Includes the following steps: (1) Add the raw materials of unit M and unit Q to organic solvent 1, mix them evenly, then add a mixture of alkali 1, water and short-chain alcohol 1 dropwise, and heat to carry out alkali-catalyzed hydrolysis condensation reaction; (2) After the reaction is completed, the product is concentrated under reduced pressure, filtered, the filtrate is taken and the solvent is removed, and the resulting solid is MQ silicone resin.

2. The alkaline-catalyzed synthesis method of MQ silicone resin according to claim 1, characterized in that, The raw material for unit M is at least one of methoxytrimethylsilane, methoxyvinyldimethylsilane, methoxyphenyldimethylsilane, or ethoxytrimethylsilane; the raw material for unit Q is at least one of ethyl silicate or tetramethoxysilane, and tetramethoxysilane accounts for less than 50% of the total molar amount of the raw material for unit Q; the molar ratio of the raw material for unit M to the raw material for unit Q is 0.8~1.5:1; The alkali 1 is at least one of sodium carbonate, potassium carbonate, cesium carbonate, lithium alkoxide, sodium alkoxide, potassium alkoxide, lithium trimethylsilyl alkoxide, sodium trimethylsilyl alkoxide, potassium trimethylsilyl alkoxide, lithium hydroxide, sodium hydroxide, potassium hydroxide, cesium hydroxide, tetramethylammonium hydroxide, tetrabutylammonium hydroxide, and volatile tertiary amine, and the amount used is 50 to 500 ppm of the total mass of the organosilicon compound raw material; The molar amount of water used is 30-61% of the total molar amount of alkoxy groups in the organosilicon compound raw material; The short-chain alcohol 1 is methanol or ethanol, and its dosage is 50-150% of the total mass of water; The organic solvent 1 is at least two of methanol, ethanol, tetrahydrofuran, propyl ether, anisole, toluene, xylene, methyl acetate, ethyl acetate, and methyl propionate, and not all of them are alcohols at the same time. The amount used is 50 to 150% of the mass of the raw material in unit Q.

3. The alkaline-catalyzed synthesis method of MQ silicone resin according to claim 1, characterized in that, The alkaline-catalyzed hydrolysis-condensation reaction is carried out at a temperature of 40-70°C for 8-48 hours.

4. The alkaline-catalyzed synthesis method of MQ silicone resin according to claim 1, characterized in that, Before mixing in step (1), a silane compound containing glycidyl ether oxypropyl is added, and the final solid obtained is epoxy-modified MQ silicone resin.

5. The alkaline-catalyzed synthesis method of MQ silicone resin according to claim 4, characterized in that, The silane compound containing glycidyl etheroxypropyl is 3-glycidyl etheroxypropyltrimethoxysilane or 3-glycidyl etheroxypropylmethyldimethoxysilane, 3-glycidyl etheroxypropyltriethoxysilane, or 3-glycidyl etheroxypropylmethyldiethoxysilane; the molar ratio of the silane compound containing glycidyl etheroxypropyl to the raw material of unit Q is 0.001~0.02:

1.

6. An MQ silicone resin, prepared by the method according to any one of claims 1 to 5; wherein the number-average molecular weight of the MQ silicone resin is 5000 to 10000 and the weight-average molecular weight is 8000 to 25000.

7. An MQ silicone resin-based high-viscosity organosilicon pressure-sensitive adhesive, characterized in that, Includes the MQ silicone resin as described in claim 6.

8. The MQ silicone resin-based high-viscosity organosilicon pressure-sensitive adhesive according to claim 7, characterized in that, By weight, the MQ silicone resin-based high-viscosity organosilicon varistor comprises: Pressure-sensitive adhesive base material: 150-215 parts Platinum catalyst 30~100×10 -6 share, Inhibitor 0.2~0.6 parts, 0.5-3 parts of hydrogen-containing silicone oil crosslinking agent; The pressure-sensitive adhesive base comprises the following components: MQ silicone resin 50-65 parts, 15-25 parts of hydroxyl-terminated polydimethylsiloxane 10-25 parts of vinyl polysiloxane The above components total 100 portions; Organic solvent 2 50~100 parts, 0-1.2 parts of tackifying resin.

9. The Q-based high-viscosity silicone pressure-sensitive adhesive according to claim 8, characterized in that, The tackifying resin is a glycidyl ether oxypropyl silyl hydrolytic cocondensation oligomer, and its preparation method is as follows: The difunctional organosilicon monomers of 3-glycidyl etheroxypropyltrimethoxysilane and / or 3-glycidyl etheroxypropylmethyldimethoxysilane, vinyltrimethoxysilane, and dimethylsilane are mixed evenly in a molar ratio of 1:0.5~1.2:0.5~4. A mixture of alkali 2, water, and short-chain alcohol 2 is added dropwise under stirring. The mixture is heated to 50~60℃ and reacted for 4~24 hours. After neutralization, the solvent and volatile substances are removed under reduced pressure. The mixture is then filtered, and the resulting liquid is the thickening resin. The difunctional organosilicon monomer containing dimethylsilicon is a small-molecule terminal hydroxyl silicone oil with a molecular weight of less than 1000 or a dimethyldimethoxysilane. The alkali 2 is at least one of sodium carbonate, potassium carbonate, cesium carbonate, lithium hydroxide, sodium hydroxide, potassium hydroxide, cesium hydroxide, tetramethylammonium hydroxide, and tetrabutylammonium hydroxide, and the amount used is 50 to 300 ppm of the total mass of the organosilicon compound raw material; The molar amount of water used is 80-95% of the total molar amount of alkoxy groups in the organosilicon compound; The short-chain alcohol 2 is methanol or ethanol, and its amount is 50-100% of the total mass of water.

10. The Q-based high-viscosity silicone pressure-sensitive adhesive according to claim 8, characterized in that, The hydroxyl-terminated polydimethylsiloxane is a double-hydroxyl-terminated polydimethylsiloxane with a number-average molecular weight of 300,000 to 1,000,000. The vinyl polysiloxane is at least one of multi-terminated vinyl polysiloxane, dual-terminated vinyl polysiloxane, or end-sided vinyl polysiloxane; the multi-terminated vinyl polysiloxane is at least one of tri-terminated vinyl polydimethylsiloxane or tetra-terminated vinyl polydimethylsiloxane; the end-sided vinyl polydimethylsiloxane is a high molecular weight polydimethylsiloxane containing both end-sided and end-sided vinyl groups, with an average of 3 to 12 vinyl groups per molecule and a number-average molecular weight of 250,000 to 600,000. The organic solvent 2 is at least one of toluene, xylene, cyclohexane, solvent oil, or ethyl acetate, methyl acetate, propyl acetate, butyl acetate, methyl propionate, ethyl propionate, and propyl propionate. The platinum catalyst is a Karstedt catalyst with a concentration of 1000~10000ppm; The inhibitor is at least one of 1-ethynylcyclohexanol, 2-methyl-3-butyn-2-ol or diallyl maleate. The hydrogen-containing silicone oil crosslinking agent is dimethyl silicone oil with an active hydrogen content of 0.6~1.55wt%.

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