Soluble bridged MQ silicon resin prepared by condensation method as well as preparation method and application of soluble bridged MQ silicon resin

Abstract

The invention belongs to the field of advanced organic silicon materials, and discloses soluble bridged MQ silicon resin prepared by a condensation method as well as a preparation method and application of the soluble bridged MQ silicon resin. The preparation method comprises the following steps: carrying out a dealcoholization condensation reaction on a raw material MQ silicon resin containing siloxy or silanol and at least one of double-end silanol polydimethylsiloxane, bifunctional or trifunctional siloxy silane or polydimethylsiloxane at 30-130 DEG C for 2-12 hours by virtue of a catalyst, so as to obtain the soluble single-bridged, double-bridged or multi-bridged MQ silicon resin. After being dried, the components can be dissolved in an organic solvent and can also be uniformly dispersed in a polydimethylsiloxane matrix or an organic silicon modified polymer. The bridged MQ silicon resin is applied to an organic silicon adhesive or a polymer coating, the peel strength of a pressure-sensitive adhesive and a release coating, the hardness of a pouring sealant and the hydrophobicity of the coating are remarkably improved, and the bridged MQ silicon resin has a wide application prospect.

Description

Technical Field

[0001] The invention belongs to the field of advanced organic silicon materials, and in particular relates to a soluble bridged MQ silicone resin prepared by a condensation method, a preparation method and an application thereof. Background Art

[0002] MQ silicone resin is a kind of compact sphere with a core-shell double-layer structure composed of monofunctional segments (M segments) and tetrafunctional segments (Q segments). The core part of the sphere is formed by polycondensation of Q segments, and the shell part is capped by M segments. MQ silicone resin has excellent weather resistance, radiation resistance and lubricity. It is mainly used for polymer adhesive reinforcement and silicone pressure-sensitive adhesive tackifier. The dispersibility of MQ resin in polydimethylsiloxane directly affects its performance. In addition, MQ silicone resin is used in coatings, surfactants, personal care products, etc.

[0003] The preparation methods of MQ silicone resin can be mainly divided into water glass method and silicate method. Among them, the water glass method has easy-to-obtain raw materials, low cost, low molecular weight and poor stability; the silicate method has mild reaction conditions, high yield and good product stability, but high cost. Due to its specific spherical structure, its compatibility with polydimethylsiloxane needs to be improved. There is no literature report on soluble bridged MQ silicone resin, preparation method and application. Summary of the invention

[0004] In order to overcome the shortcomings and deficiencies in the above-mentioned prior art, the primary purpose of the present invention is to provide a soluble bridged MQ silicone resin, which can not only greatly increase the molecular weight of the silicone resin and be soluble in organic solvents, but also significantly improve its compatibility with polydimethylsiloxane or its modified polymers, and be uniformly and stably dispersed in the matrix polymer.

[0005] Another object of the present invention is to provide a method for preparing the soluble bridged MQ silicone resin.

[0006] Another object of the present invention is to provide the application of the soluble bridged MQ silicone resin.

[0007] The purpose of the present invention is achieved through the following technical solutions:

[0008] A soluble bridged MQ silicone resin prepared by a condensation method, characterized in that the soluble bridged MQ silicone resin is at least one of a soluble single-bridged MQ silicone resin, a soluble double-bridged MQ silicone resin, and a soluble multi-bridged MQ silicone resin;

[0009] The structural formula of the soluble bridged MQ silicone resin is shown in the following formula (1) or (2):

[0010]

[0011] Wherein, n1, n2 = 3 to 200, a = 0 to 5, b1, b2 = 0 to 5, and R represents at least one of C1 to C18 alkyl, methoxy, and ethoxy;

[0012] The number average molecular weight of the soluble bridged MQ silicone resin is 3,000 to 100,000.

[0013] Preferably, the soluble bridged MQ silicone resin is prepared by a dealcoholization condensation reaction of a raw material MQ silicone resin containing silanol or silanol with at least one of dihydroxyl-terminated polydimethylsiloxane, difunctional or trifunctional alkoxysilane or polydimethylsiloxane in the presence of a catalyst at 30 to 130° C. for 2 to 12 hours.

[0014] Preferably, the soluble bridged MQ silicone resin is soluble in an organic solvent and can be uniformly dispersed in polysiloxane or organosilicon-modified polymer;

[0015] The organic solvent is at least one of ethyl acetate, butyl acetate, ethanol, propanol, isopropanol, chloroform, tetrahydrofuran, toluene, xylene, C6-C10 alkane or cycloalkane.

[0016] The method for preparing the soluble bridged MQ silicone resin of the present invention is characterized in that:

[0017] (I) adding 40 to 200 parts by mass of an organic solvent to dissolve 100 parts by mass of a raw material MQ silicone resin containing silane groups, adding 2 to 100 parts by mass of a double-terminated hydroxyl polydimethylsiloxane and 0.01 to 0.5 parts by mass of a catalyst, reacting at 30 to 130° C. for 2 to 12 hours, and finally removing the catalyst by neutralization, heating and / or decompression to obtain a soluble bridged MQ silicone resin;

[0018] or,

[0019] (II) adding 40 to 200 parts by mass of an organic solvent to dissolve 100 parts by mass of a raw material MQ silicone resin containing silanol groups, adding 2 to 20 parts by mass of an alkyltrialkoxysilane and 0.01 to 0.5 parts by mass of a catalyst, reacting at 30 to 130° C. for 1 to 6 hours, then adding 10 to 100 parts by mass of a double-terminal hydroxyl polydimethylsiloxane and continuing the reaction for 2 to 6 hours, and finally removing the catalyst by neutralization, heating and / or reducing pressure to obtain a soluble bridged MQ silicone resin;

[0020] or,

[0021] (III) After 100 parts by weight of MQ silicone resin containing silanol groups is dissolved by adding 40 to 200 parts by weight of an organic solvent, 10 to 100 parts by weight of a double-ended alkoxy polydimethylsiloxane and 0.01 to 0.5 parts by weight of a catalyst are added, and the mixture is reacted at 30 to 130° C. for 3 to 12 hours. Finally, the catalyst is removed by neutralization, heating and / or decompression to obtain a soluble bridged MQ silicone resin.

[0022] Preferably, the raw material MQ silicone resin containing silicon alkoxy groups has an alkoxy group of methoxy or ethoxy, an alkoxy content of not less than 0.3wt%, an M / Q ratio of 0.6 to 0.9, a number average molecular weight of 1500 to 10000, and is at least one of methyl MQ silicone resin and vinyl MQ silicone resin;

[0023] The raw material MQ silicone resin containing silanol has a hydroxyl content of not less than 0.2wt%, an M / Q ratio of 0.6-0.9, a number average molecular weight of 1500-10000, and is at least one of methyl MQ silicone resin and vinyl MQ silicone resin.

[0024] Preferably, in method (II), the alkyltrialkoxysilane is at least one of C1-C18 alkyltrimethoxysilane and C1-C18 alkyltriethoxysilane; in method (III), the alkoxy group of the double-terminal alkoxy polydimethylsiloxane is methoxy or ethoxy.

[0025] Preferably, the organic solvent is at least one of toluene and xylene; the catalyst is at least one of volatile alkylamine, tetramethylammonium hydroxide, tetraethylammonium hydroxide, lithium alcoholate, sodium alcoholate, and potassium alcoholate; the neutralizing acid is a C8-C18 long-chain alkyl carboxylic acid, specifically at least one of isooctanoic acid and lauric acid; and the heating temperature when removing the catalyst is 60-130°C.

[0026] The invention discloses an application of the soluble bridged MQ silicone resin in organic silicone pressure-sensitive adhesives, potting adhesives, release coatings or protective coatings.

[0027] Preferably, in the organic silicone pressure-sensitive adhesive and the potting adhesive, the addition amount of the soluble bridging MQ silicone resin is 50wt% to 100wt% of the main agent of the organic silicone pressure-sensitive adhesive and the potting adhesive.

[0028] Preferably, in the release coating and the protective coating, the addition amount of the soluble bridged MQ silicone resin is 10wt% to 20wt% of the main agent of the release coating and the protective coating.

[0029]

[0030] MQ silicone resin is a kind of compact sphere with a core-shell double-layer structure composed of monofunctional chain segments (M chain segments) and tetrafunctional chain segments (Q chain segments). The core part of the sphere is formed by condensation of Q chain segments, and the shell part is capped by M chain segments. As shown in the above formula (3), when R 1 CH 3 When R 1 for —CH═CH 2 When, it is vinyl MQ silicone resin; wherein, R 2 =—H,—CH 3 , —C 2 H 5 , when R 2 When it is -H, it is MQ silicone resin containing silanol groups; when R 2 CH 3 or—C 2 H 5 When , it is MQ silicone resin containing siloxane. The preparation methods of MQ silicone resin can be mainly divided into water glass method and silicate method. Among them, the water glass method has easy-to-obtain raw materials and low cost, and the obtained MQ silicone resin is mainly composed of a large number of silanol groups, with low molecular weight and poor stability; the silicate method has mild reaction conditions, high yield, good product stability, but high cost, and the obtained MQ silicone resin is silanol-containing.

[0031] Due to the specific spherical structure, the unmodified MQ silicone resin has poor compatibility with linear polydimethylsiloxane, and is easy to become turbid or precipitate, especially the MQ silicone resin containing a large amount of silanol prepared by the water glass method, and the precipitation is more significant. At the same time, due to the large volume of MQ silicone resin, the condensation itself is not easy to occur. The present invention uses a small volume of double-terminal hydroxyl polydimethylsiloxane or double-terminal alkoxy polydimethylsiloxane containing a certain length (link) as a bridge, and respectively with a large volume of MQ silicone resin containing silicon alkoxy or a raw material MQ silicone resin containing silicon hydroxy, through a base-catalyzed dealcoholization condensation reaction to obtain a single-bridged, two-bridged or multi-bridged MQ silicone resin, wherein the alkoxy-containing MQ silicone resin can be a raw material MQ silicone resin prepared from a silicate method, or a raw material MQ silicone resin containing silicon hydroxy prepared by the water glass method is first pre-condensed with a trialkoxysilane to obtain a modified MQ silicone resin containing alkoxy. After the raw material MQ silicone resin is bridged and connected by a dimethylsiloxane chain containing a certain number of chain segments, its compatibility with the polydimethylsiloxane matrix is ​​greatly improved, so that it can be dissolved and dispersed in both organic solvents and polysiloxane systems, so that it can fully exert its reinforcing, physical and chemical cross-linking effects in the matrix resin system. The experimental results show that the bridging MQ silicone resin prepared by the present invention has a significantly improved peel strength in the application of solvent-based organic pressure-sensitive adhesives at a higher dosage, and in silicone potting glue, a transparent silicone rubber with a higher hardness can be obtained. In the application of solvent-free silicone release agents with a lower dosage, the peel strength is also significantly improved, and it can be used for heavy-peeling silicone release agents; in solvent-based silicone-modified acrylate coatings, the water contact angle is significantly improved, which is conducive to a significant improvement in hydrophobic and anti-fouling properties.

[0032] Compared with the prior art, the present invention has the following advantages and effects:

[0033] (1) A new type of bridged MQ silicone resin is obtained by connecting the repeating units of linear dimethylsiloxy chains, which not only significantly increases the molecular weight of the MQ silicone resin containing silanol groups or silanol groups, but also significantly improves the compatibility with polydimethylsiloxane.

[0034] (2) The bridged MQ silicone resin prepared by the present invention significantly improves the peel strength of solvent-based silicone pressure-sensitive adhesives and solvent-free silicone release agents, greatly improves the hardness of transparent silicone potting adhesives and the hydrophobicity and antifouling properties of silicone-modified acrylate polymer coatings.

[0035] (3) The preparation method of the present invention is simple, has obvious cost advantages, and is conducive to industrial production. DETAILED DESCRIPTION

[0036] The present invention is further described in detail below in conjunction with examples, but the embodiments of the present invention are not limited thereto.

[0037] Example 1

[0038] 100 g of MQ1 silicone resin (M / Q ratio of 0.68, number average molecular weight of 5200) containing 1.3 wt% of ethoxy groups was added with 100 g of toluene and stirred to dissolve, and then 80 g of dihydroxy-terminated polydimethylsiloxane (number average molecular weight of 8600) and 0.01 g of sodium methoxide were added respectively, reacted at 30° C. for 12 hours, and then 0.03 g of isooctanoic acid was added for neutralization, and the solvent was removed under reduced pressure at 60° C. to obtain a viscous bridged MQ silicone resin (QLMQ1). Samples were taken, and the MQ silicone resin was subjected to solvent test, GPC test and dispersion test in silicone oil, and the results are listed in Table 2.

[0039] In solvent tests, the MQ silicone resin was soluble in xylene, ethyl acetate, isopropanol, cyclohexane, chloroform, and tetrahydrofuran to obtain a clear 50 wt% solution.

[0040] The test results of gel permeation chromatography (GPC) show that the number average molecular weight increases significantly from the original 5200 to 18200, and it is a soluble MQ silicone resin mainly composed of single bridges as shown in formula (1).

[0041] The solvent dispersion test in silicone oil is as follows (the same as Examples 1 to 9): first, 10 g of the raw material MQ silicone resin or the bridged MQ silicone resin obtained in the example is dissolved in 20 g of toluene, and then added to 10 g of terminal hydroxyl polydimethylsiloxane (hydroxyl silicone oil 500 mPa·s) and 10 g of vinyl polydimethylsiloxane (vinyl silicone oil 500 mPa·s) at 80°C, respectively. After removing the solvent under reduced pressure, cool to room temperature to obtain a MQ silicone resin silicone oil dispersion with a mass ratio of 1:1, and observe its appearance.

[0042] The solvent-free dispersion test in silicone oil is as follows (the same as in Examples 1 to 9): 50 g of hydroxy silicone oil (500 mPa·s) or 50 g of vinyl silicone oil (500 mPa·s) is heated to 160°C under nitrogen, and 5 g of the bridged MQ silicone resin prepared in Examples 1 to 9 is added to the hot silicone oil under rapid stirring, and the mixture is cooled after being stirred for 2 hours at a temperature maintained at room temperature, and its appearance is observed.

[0043] The experimental results show that in the solvent method, the raw material MQ silicone resin is turbid in both silicone oils, while the bridged MQ silicone resin is transparent and has no phase separation in the silicone oil; in the solvent-free method, the raw material MQ silicone resin is turbid in both silicone oils, while the bridged MQ silicone resin is transparent and has no precipitation in the silicone oil.

[0044] Example 2

[0045] 100 g of MQ1 silicone resin (M / Q ratio of 0.68, number average molecular weight of 5200) containing 1.3 wt% of ethoxy groups was added with 50 g of xylene and stirred to dissolve, and then 4.5 g of double-terminal hydroxyl polydimethylsiloxane (number average molecular weight of 500) and 0.02 g of tetramethylammonium hydroxide were added respectively, and the temperature was raised to 80° C. for reaction for 2 hours, and then 0.05 g of lauric acid was added for neutralization, and the solvent was removed under reduced pressure after heating to 130° C. to obtain a solid bridged MQ silicone resin (QLMQ2). Samples were taken, and the solid MQ silicone resin was subjected to solvent test, GPC test and dispersion test in silicone oil, and the results are listed in Table 2.

[0046] In solvent tests, the MQ silicone resin was soluble in xylene, ethyl acetate, isopropanol, cyclohexane, chloroform, and tetrahydrofuran to obtain a clear 50 wt% solution.

[0047] The GPC test results show that its number average molecular weight has increased significantly, almost doubling from the original 5200 to 10300. It is a soluble MQ silicone resin mainly composed of single bridges as shown in formula (1).

[0048] The results of the dispersion experiment in silicone oil medium are that the raw material MQ silicone resin in the solvent method is turbid in both silicone oils, while the bridged MQ silicone resin is transparent and has no phase separation in the silicone oil; the raw material MQ silicone resin in the solvent-free method is turbid in both silicone oils, while the bridged MQ silicone resin is transparent and has no precipitation in the silicone oil.

[0049] Example 3

[0050] 100 g of raw material vinyl MQ2 silicone resin (M / Q ratio of 0.85, number average molecular weight of 1810, vinyl content of 0.1 wt%) containing 1.8 wt% of methoxy groups was added with 50 g of toluene and stirred to dissolve, and then 11 g of double-terminal hydroxyl polydimethylsiloxane (number average molecular weight of 390) and 0.4 g of dimethylbutylamine were added respectively, and the temperature was raised to 90° C. for reaction for 6 hours, and then the solvent and catalyst were removed at 90° C. and reduced pressure to obtain solid bridged MQ silicone resin (QLMQ3). Samples were taken, and the solid MQ silicone resin was subjected to solvent test, GPC test and dispersion test in silicone oil, and the results are listed in Table 2.

[0051] In solvent tests, the MQ silicone resin was soluble in xylene, ethyl acetate, isopropanol, cyclohexane, chloroform, and tetrahydrofuran to obtain a clear 50 wt% solution.

[0052] The GPC test results show that its number average molecular weight has increased significantly, almost doubling from the original 1810 to 3870. It is a soluble MQ silicone resin mainly composed of single bridges as shown in formula (1).

[0053] The results of the dispersion experiment in silicone oil medium are that the raw material MQ silicone resin in the solvent method is turbid in both silicone oils, while the bridged MQ silicone resin is transparent and has no phase separation in the silicone oil; the raw material MQ silicone resin in the solvent-free method is turbid in both silicone oils, while the bridged MQ silicone resin is transparent and has no precipitation in the silicone oil.

[0054] Example 4

[0055] 100 g of MQ3 silicone resin (M / Q ratio of 0.67, number average molecular weight of 8640) containing 0.4 wt% of methoxy groups was added with 100 g of toluene and stirred to dissolve, and then 83 g of double-terminal hydroxyl polydimethylsiloxane (number average molecular weight of 14500) and 0.06 g of lithium methoxide were added respectively, reacted at 50° C. for 6 hours, and then 0.25 g of isooctanoic acid was added for neutralization, and the solvent was removed under reduced pressure at 80° C. to obtain a viscous liquid bridged MQ silicone resin (QLMQ4). Samples were taken, and the MQ silicone resin was subjected to solvent test, GPC test and dispersion test in silicone oil, and the results are listed in Table 2.

[0056] In solvent tests, the MQ silicone resin was soluble in xylene, ethyl acetate, isopropanol, cyclohexane, chloroform, and tetrahydrofuran to obtain a clear 50 wt% solution.

[0057] The GPC test results show that the number average molecular weight increases significantly from the original 8640 to 31200, and it is a soluble MQ silicone resin mainly composed of single bridges as shown in formula (1).

[0058] The results of the dispersion experiment in silicone oil medium are that the raw material MQ silicone resin in the solvent method is turbid in both silicone oils, while the bridged MQ silicone resin is transparent and has no phase separation in the silicone oil; the raw material MQ silicone resin in the solvent-free method is turbid in both silicone oils, while the bridged MQ silicone resin is transparent and has no precipitation in the silicone oil.

[0059] Example 5

[0060] 100 g of MQ4 silicone resin (M / Q ratio of 0.61, number average molecular weight of 7300) containing 0.82 wt% of methoxy groups was added with 50 g of toluene and stirred to dissolve, and then 5 g of double-terminal hydroxyl polydimethylsiloxane (number average molecular weight of 500) and 0.05 g of lithium methoxide were added respectively, reacted at 50° C. for 3 hours, and then 0.20 g of isooctanoic acid was added for neutralization, and the solvent was removed under reduced pressure at 80° C. to obtain a solid bridged MQ silicone resin (QLMQ5). Samples were taken, and the MQ silicone resin was subjected to solvent test, GPC test and dispersion test in silicone oil, and the results are listed in Table 2.

[0061] In solvent tests, the MQ silicone resin was soluble in xylene, ethyl acetate, isopropanol, cyclohexane, chloroform, and tetrahydrofuran to obtain a clear 50 wt% solution.

[0062] The GPC test results show that the number average molecular weight has increased significantly from the original 7300 to 30100, and it is a soluble MQ silicone resin mainly composed of multiple bridges as shown in formula (1).

[0063] The results of the dispersion experiment in silicone oil medium are that the raw material MQ silicone resin in the solvent method is turbid in both silicone oils, while the bridged MQ silicone resin is transparent and has no phase separation in the silicone oil; the raw material MQ silicone resin in the solvent-free method is turbid in both silicone oils, while the bridged MQ silicone resin is transparent and has no precipitation in the silicone oil.

[0064] Example 6

[0065] 100 g of MQ5 silicone resin (M / Q ratio of 0.70, number average molecular weight of 1550) containing 1.2 wt% of hydroxyl was added with 50 g of xylene and stirred to dissolve, then 10.5 g of propyltrimethoxysilane and 0.2 g of dimethylbutylamine were added respectively, the temperature was raised to 100°C and refluxed for 2 hours, then 24 g of double-terminal hydroxyl polydimethylsiloxane (number average molecular weight of 500) was added and the temperature was kept at 100°C for 4 hours, then the solvent and catalyst were removed under reduced pressure at 100°C to obtain a solid bridged MQ silicone resin (QLMQ6). Samples were taken, and the solid MQ silicone resin was subjected to solvent test, GPC test and dispersion test in silicone oil, and the results are listed in Table 2.

[0066] In solvent tests, the MQ silicone resin was soluble in xylene, ethyl acetate, isopropanol, cyclohexane, chloroform, and tetrahydrofuran to obtain a clear 50 wt% solution.

[0067] The GPC test results show that its number average molecular weight has increased significantly from the original 1550 to 7930, and it is a soluble MQ silicone resin mainly composed of multiple bridges as shown in formula (2).

[0068] The results of the dispersion experiment in silicone oil medium are that the raw material MQ silicone resin in the solvent method is turbid in both silicone oils, while the bridged MQ silicone resin is transparent and has no phase separation in the silicone oil; the raw material MQ silicone resin in the solvent-free method precipitates in both silicone oils, while the bridged MQ silicone resin is transparent and has no precipitation in the silicone oil.

[0069] Example 7

[0070] 100 g of raw material vinyl MQ6 silicone resin (M / Q ratio of 0.72, number average molecular weight of 1930, vinyl content of 0.15 wt%) containing 0.9 wt% of hydroxyl was added to 50 g of toluene and stirred to dissolve, then 14.5 g of dodecyl trimethoxy silane and 0.05 g of lithium methoxide were added respectively, the temperature was raised to 50°C for reaction for 3 hours, and then 75 g of double-terminal hydroxyl polydimethylsiloxane (number average molecular weight of 2000) was added and reacted at 50°C for 4 hours. Finally, 0.21 g of isooctanoic acid was added for neutralization, and the solvent was removed under reduced pressure at 80°C to obtain a viscous liquid bridged MQ silicone resin (QLMQ7). Samples were taken, and the MQ silicone resin was subjected to solvent test, GPC test and dispersion test in silicone oil, and the results are listed in Table 2.

[0071] In solvent tests, the MQ silicone resin was soluble in xylene, ethyl acetate, isopropanol, cyclohexane, chloroform, and tetrahydrofuran to obtain a clear 50 wt% solution.

[0072] The GPC test results show that its number average molecular weight has increased significantly from the original 1930 to 13600, and it is a soluble MQ silicone resin mainly composed of multiple bridges as shown in formula (2).

[0073] The results of the dispersion experiment in silicone oil medium are that the raw material MQ silicone resin in the solvent method is turbid in both silicone oils, while the bridged MQ silicone resin is transparent and has no phase separation in the silicone oil; the raw material MQ silicone resin in the solvent-free method precipitates in both silicone oils, while the bridged MQ silicone resin is transparent and has no precipitation in the silicone oil.

[0074] Example 8

[0075] 100 g of MQ5 silicone resin (M / Q ratio of 0.70, number average molecular weight of 1550) containing 1.2 wt% of hydroxyl was added with 50 g of toluene and stirred to dissolve, then 19 g of double-terminal methoxy polydimethylsiloxane (number average molecular weight of 600) and 0.2 g of dimethylbutylamine were added respectively and reacted at 90° C. for 4 hours, then the solvent and catalyst were removed under reduced pressure at 90° C. to obtain a solid bridged MQ silicone resin (QLMQ8). Samples were taken, and the solid MQ silicone resin was subjected to solvent test, GPC test and dispersion test in silicone oil, and the results are listed in Table 2.

[0076] In solvent tests, the MQ silicone resin was soluble in xylene, ethyl acetate, isopropanol, cyclohexane, chloroform, and tetrahydrofuran to obtain a clear 50 wt% solution.

[0077] The GPC test results show that the number average molecular weight increases significantly from the original 1550 to 3590, and it is a soluble MQ silicone resin mainly composed of single bridges as shown in formula (1).

[0078] The results of the dispersion experiment in silicone oil medium are that the raw material MQ silicone resin in the solvent method is turbid in both silicone oils, while the bridged MQ silicone resin is transparent and has no phase separation in the silicone oil; the raw material MQ silicone resin in the solvent-free method precipitates in both silicone oils, while the bridged MQ silicone resin is transparent and has no precipitation in the silicone oil.

[0079] Example 9

[0080] 100 g of raw material vinyl MQ6 silicone resin (M / Q ratio of 0.72, number average molecular weight of 1930, vinyl content of 0.15 wt%) containing 0.9 wt% of hydroxyl group was added to 80 g of toluene and stirred to dissolve, and then 78 g of double-terminal methoxy polydimethylsiloxane (number average molecular weight of 3100) and 0.08 g of lithium methoxide were added to react at 40° C. for 10 hours, and then 0.33 g of isooctanoic acid was added for neutralization, and finally the solvent was removed under reduced pressure at 60° C. to obtain a viscous liquid bridged MQ silicone resin (QLMQ9). Samples were taken, and the MQ silicone resin was subjected to solvent test, GPC test and dispersion test in silicone oil, and the results are listed in Table 2.

[0081] In solvent tests, the MQ silicone resin was soluble in xylene, ethyl acetate, isopropanol, cyclohexane, chloroform, and tetrahydrofuran to obtain a clear 50 wt% solution.

[0082] The GPC test results show that its number average molecular weight has increased significantly from the original 1930 to 6790, and it is a soluble MQ silicone resin mainly composed of single bridges as shown in formula (1).

[0083] The results of the dispersion experiment in silicone oil medium are that the raw material MQ silicone resin in the solvent method is turbid in both silicone oils, while the bridged MQ silicone resin is transparent and has no phase separation in the silicone oil; the raw material MQ silicone resin in the solvent-free method precipitates in both silicone oils, while the bridged MQ silicone resin is transparent and has no precipitation in the silicone oil.

[0084] Table 1: Molecular weight of raw material MQ silicone resin and dissolution and dispersion test results

[0085]

[0086] Table 2: Molecular weight and dissolution and dispersion test results of bridged MQ silicone resin obtained in Examples 1 to 9

[0087]

[0088]

[0089] As can be seen from the above, the bridged MQ silicone resin prepared in the present invention not only has a molecular weight that is more than doubled, but can also be dissolved and dispersed in organic solvents, hydroxyl-terminated polydimethylsiloxane and vinyl polydimethylsiloxane, and its compatibility is significantly improved.

[0090] Example 10: Application test example

[0091] 10-1: Silicone pressure-sensitive adhesive

[0092] (1) Preparation of pressure-sensitive adhesive:

[0093] Pressure-sensitive adhesive components: main agent is 3 million mPa·s vinyl rubber, the dosage is 100; solvent is xylene:ethyl acetate with a mass ratio of 1:1; cross-linking agent is 1.2wt% hydrogen-containing silicone oil, the dosage is 1.5wt% of the main agent; catalyst is Karsted platinum catalyst, the dosage is 40ppm of the main agent; inhibitor is ethynyl cyclohexanol, the dosage is 0.2wt% of the main agent; additives are bridged MQ silicone resin prepared in Examples 1 to 9 of the present invention and raw material MQ5 silicone resin, the dosage is 50wt% and 100wt% of the main agent respectively. The solid content of the pressure-sensitive adhesive is 30wt%.

[0094] The pressure-sensitive adhesive components were fully and evenly stirred using a mechanical stirrer according to the ratio for 10 minutes. The stirred pressure-sensitive adhesive was manually coated on a 50 μm PET film and allowed to stand at room temperature for 10 minutes after coating. The coating polymer thickness was 11-12 μm and cured at 150° C. for 2 minutes to obtain the pressure-sensitive adhesive after thermal curing.

[0095] Peel force test: Test conditions are temperature 23±2℃, humidity 50±5%RH; test roller 2000±50g; test strip width 25mm, length 300mm. Test speed 300mm / min; test sample is left at 23±2℃, 50±5%RH for 2H.

[0096] Cut the coated PET film material, peel off the fluorine release film, lay it flat on the table with the adhesive surface facing up, and then stick the low-peeling adhesive surface on the high-viscosity adhesive surface, requiring the adhesive surface to fit without bubbles; after sticking, use a manual sampler to take samples. With the adhesive surface of the sample end facing down, roll it back and forth slowly and evenly for 3 times with a 2 kg roller, and let it stand for 30 minutes; stick one side of the double-sided high-viscosity tape flat on the 304 stainless steel plate, and tear off the release film after sticking; roll the back of the test sample with a 2 kg roller back and forth slowly and evenly for 2 times, and fix it on the double-sided tape; first manually reset to zero and then fix the lower end of the 304 stainless steel on the lower fixture of the tensile machine, and fix the low-peeling end of the test sample on the upper fixture of the tensile machine, and then reset to zero to test the 180° peel strength. The test results are listed in Table 3.

[0097] 10-2: Application of solvent-free transparent potting glue

[0098] The main agent of the potting glue is 20,000 mPa·s vinyl silicone oil, the dosage is 100; the cross-linking agent is 1.2wt% hydrogen-containing silicone oil, the dosage is 3wt% of the main agent; the catalyst is Karsted platinum catalyst, the dosage is 20ppm of the main agent; the inhibitor is ethynyl cyclohexanol, the dosage is 0.2wt% of the main agent; the additives are the bridged MQ silicone resin and the raw material MQ5 silicone resin prepared in Examples 1 to 9 of the present invention, the dosage is 50wt% and 100wt% of the main agent respectively. The potting glue components that can be dispersed uniformly are fully stirred by mechanical stirring according to the proportion, the stirring time is 3 minutes, and a transparent potting glue is obtained. The stirred potting glue is poured into a mold, and after defoaming, it is placed in a 120℃ oven for curing for 4 hours, cooled, and a transparent solidified material is obtained. Its Shore hardness is tested, and the results are uniformly listed in Table 3.

[0099] Table 3: Test results of application of bridged MQ silicone resin in solvent-based pressure-sensitive adhesive and solvent-free potting adhesive

[0100]

[0101] It can be seen from the experimental results in Table 3 that in the solvent-based silicone pressure-sensitive adhesive at high dosage, when the raw material MQ silicone resin without bridging is 50% and 100% of the main agent, its 180° peel strength is only 68 and 150g / 25mm respectively, while when the bridging MQ silicone resin of the present invention is used at 50% and 100% high dosage, the corresponding dosage increases by more than 1 times. In the solvent-free silicone potting adhesive, the unmodified MQ silicone resin precipitates in the system, while the bridged MQ silicone resin prepared by the present invention is compatible and transparent in the system and has a higher Shore hardness.

[0102] 10-3: Application in release coating

[0103] (1) Preparation of release film:

[0104] Release agent components: the main agent is 200mPa·s terminal vinyl silicone oil, the amount of which is 100; the cross-linking agent is 1.2wt% hydrogen-containing silicone oil, the amount of which is 6.0wt% of the main agent; the catalyst is Karsted platinum catalyst, the amount of which is 40ppm of the main agent; the inhibitor is ethynyl cyclohexanol, the amount of which is 0.2wt% of the main agent; the additive is the bridged MQ silicone resin prepared in Examples 1 to 9 of the present invention, the amounts of which are 0, 10wt% and 20wt% of the main agent respectively.

[0105] The release agent components were stirred evenly by mechanical stirring according to the proportions for 10 minutes, the stirred release agent was coated on glassine paper, and after coating, it was cured at 160° C. for 5 seconds, and the coating thickness was 0.8-0.9 g / m2. A release film was obtained after thermal curing.

[0106] (2) Peel force test: Samples of the release films prepared in Examples 1 to 9 and the blank were taken and pasted on the release films with tesa 7475 tape to prepare samples (25 mm wide and 12 cm long). A 2 kg cylindrical steel roller (GB / T2792-2014) was placed on each sample and the 180° peel force of the release films was tested at room temperature for 20 minutes. The test results are listed in Table 4.

[0107] 10-4: Application in protective coatings

[0108] 200 g of ethyl acetate, 3 g of KH570, 180 g of isobutyl methacrylate, 17 g of isooctyl acrylate and 1.5 g of azobisisobutyronitrile were added to a 1000 ml four-necked flask, and the temperature was raised to 75° C. for reflux reaction for 2 hours. After cooling, a 50 wt % acrylate polymer solution was obtained. 0 g, 1 g and 2 g of the bridged MQ silicone resin in Examples 1 to 9 were taken respectively and added to 20 g of the acrylate polymer solution. After stirring evenly, the mixture was coated on a flat and smooth glass sheet (coating thickness 15 to 20 μm). After drying at room temperature for 3 days, a transparent coating was obtained. The water contact angles of water in the coatings were tested respectively, and the experimental results are listed in Table 4.

[0109] Table 4: Test results of application of bridged MQ silicone resin in silicone release coatings and protective coatings

[0110]

[0111]

[0112] As can be seen from Table 4, the bridged MQ silicone resin prepared by the present invention can significantly improve the peeling force of the solvent-free silicone release coating at a lower dosage of 10% and 20% relative to the blank release coating without additives. In the silicone-modified acrylate polymer coating, the water contact angle is significantly increased from 86° of the blank to more than 101°, and with the increase of the dosage of the bridged MQ silicone resin, the water contact angle increases and approaches 110°, and the hydrophobicity, water resistance and antifouling properties are significantly improved.

[0113] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be equivalent replacement methods and are included in the protection scope of the present invention.

Claims

1. A soluble bridged MQ silicone resin prepared by a condensation method, characterized in that: The soluble bridged MQ silicone resin is at least one of a soluble single-bridged MQ silicone resin, a soluble double-bridged MQ silicone resin, and a soluble multi-bridged MQ silicone resin; The structural formula of the soluble bridged MQ silicone resin is shown in the following formula (1) or (2): Wherein, n1, n2 = 3 to 200, a = 0 to 5, b1, b2 = 0 to 5, and R represents at least one of C1 to C18 alkyl, methoxy, and ethoxy; The number average molecular weight of the soluble bridged MQ silicone resin is 3,000 to 100,000.

2. A soluble bridged MQ silicone resin prepared by a condensation method according to claim 1, characterized in that: The soluble bridged MQ silicone resin is obtained by combining the raw material MQ silicone resin containing silanol or silanol with double-terminal hydroxyl polydimethylsiloxane, difunctional or trifunctional alkoxy At least one of silane or polydimethylsiloxane is prepared by dealcoholization condensation reaction at 30-130° C. for 2-12 hours with a catalyst.

3. A soluble bridged MQ silicone resin prepared by condensation method according to claim 2, characterized in that: The soluble bridged MQ silicone resin is soluble in organic solvents and can be uniformly dispersed in polysiloxane or organosilicon-modified polymers; The organic solvent is at least one of ethyl acetate, butyl acetate, ethanol, propanol, isopropanol, chloroform, tetrahydrofuran, toluene, xylene, C6-C10 alkane or cycloalkane.

4. The method for preparing the soluble bridged MQ silicone resin according to any one of claims 1 to 3, characterized in that: (I) adding 40 to 200 parts by mass of an organic solvent to dissolve 100 parts by mass of a raw material MQ silicone resin containing silane groups, adding 2 to 100 parts by mass of a double-terminated hydroxyl polydimethylsiloxane and 0.01 to 0.5 parts by mass of a catalyst, reacting at 30 to 130° C. for 2 to 12 hours, and finally removing the catalyst by neutralization, heating and / or decompression to obtain a soluble bridged MQ silicone resin; or, (II) adding 40 to 200 parts by mass of an organic solvent to dissolve 100 parts by mass of a raw material MQ silicone resin containing silanol groups, adding 2 to 20 parts by mass of an alkyltrialkoxysilane and 0.01 to 0.5 parts by mass of a catalyst, reacting at 30 to 130° C. for 1 to 6 hours, then adding 10 to 100 parts by mass of a double-terminal hydroxyl polydimethylsiloxane and continuing the reaction for 2 to 6 hours, and finally removing the catalyst by neutralization, heating and / or reducing pressure to obtain a soluble bridged MQ silicone resin; or, (III) After 100 parts by weight of MQ silicone resin containing silanol groups is dissolved by adding 40 to 200 parts by weight of an organic solvent, 10 to 100 parts by weight of a double-ended alkoxy polydimethylsiloxane and 0.01 to 0.5 parts by weight of a catalyst are added, and the mixture is reacted at 30 to 130° C. for 3 to 12 hours. Finally, the catalyst is removed by neutralization, heating and / or decompression to obtain a soluble bridged MQ silicone resin.

5. The preparation method according to claim 4, characterized in that: The raw material MQ silicone resin containing silicon alkoxy groups has methoxy or ethoxy groups, an alkoxy content of not less than 0.3wt%, an M / Q ratio of 0.6 to 0.9, a number average molecular weight of 1500 to 10000, and is at least one of methyl MQ silicone resin and vinyl MQ silicone resin; The raw material MQ silicone resin containing silanol has a hydroxyl content of not less than 0.2wt%, an M / Q ratio of 0.6-0.9, a number average molecular weight of 1500-10000, and is at least one of methyl MQ silicone resin and vinyl MQ silicone resin.

6. The preparation method according to claim 5, characterized in that: In method (II), the alkyltrialkoxysilane is at least one of C1-C18 alkyltrimethoxysilane and C1-C18 alkyltriethoxysilane; in method (III), the alkoxy group of the double-terminal alkoxy polydimethylsiloxane is methoxy or ethoxy.

7. The preparation method according to claim 6, characterized in that: The organic solvent is at least one of toluene and xylene; the catalyst is at least one of volatile alkylamine, tetramethylammonium hydroxide, tetraethylammonium hydroxide, lithium alcoholate, sodium alcoholate, and potassium alcoholate; the neutralizing acid is a C8-C18 long-chain alkyl carboxylic acid, specifically at least one of isooctanoic acid and lauric acid; and the heating temperature when removing the catalyst is 60-130°C.

8. Use of the soluble bridged MQ silicone resin according to any one of claims 1 to 3 in organic silicone pressure-sensitive adhesives, potting adhesives, release coatings or protective coatings.

9. The use according to claim 8, characterized in that: In the organic silicone pressure-sensitive adhesive and the potting adhesive, the addition amount of the soluble bridged MQ silicone resin is 50wt% to 100wt% of the main agent of the organic silicone pressure-sensitive adhesive and the potting adhesive.

10. The use according to claim 8, characterized in that: In the release coating and the protective coating, the addition amount of the soluble bridged MQ silicone resin is 10wt% to 20wt% of the main agent of the release coating and the protective coating.

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