阅读说明：本技术 一种低羟基含氢乙烯基苯基有机硅树脂及其制备方法 (Low-hydroxyl hydrogen-containing vinyl phenyl organic silicon resin and preparation method thereof ) 是由 李美江 刘美辰 侯新瑞 宋华锋 于 2019-12-31 设计创作，主要内容包括：本发明涉及有机硅树脂的技术领域,具体涉及一种低羟基含氢乙烯基苯基有机硅树脂,其结构通式为：[Me<Sub>3</Sub>SiO<Sub>0.5</Sub>]<Sub>m</Sub>[MeHSiO]<Sub>n</Sub>[MeViSiO]<Sub>q</Sub>[PhSiO<Sub>1.5</Sub>]<Sub>t</Sub>[(PO)<Sub>1/3</Sub>(CH<Sub>2</Sub>OMe<Sub>2</Sub>SiC<Sub>3</Sub>H<Sub>6</Sub>NHCOO<Sub>0.5</Sub>)]<Sub>p</Sub>；其中,m为1~10的整数,n为1~15的整数,q为1~10的整数,t为5~30的整数,p为1~3的整数,其制备方法以烷氧基硅烷混合物为原料,在氢型强酸性阳离子交换树脂与对甲基苯磺酸共同催化下,经水解-缩合反应、PO(CH<Sub>2</Sub>OMe<Sub>2</Sub>SiC<Sub>4</Sub>H<Sub>8</Sub>NCO)<Sub>3</Sub>封端反应得到。本发明克服了现有技术制备的硅树脂中羟基含量高,导致其储存粘度稳定性差,电绝缘性能较差的缺陷,本发明制备有机硅树脂硅羟基含量较低,储存期粘度稳定性好,以其为原料制备的单组份加成型有机硅浸渍漆,固化后电气绝缘性能优异。(The invention relates to the technical field of organic silicon resin, in particular to low-hydroxyl hydrogen-containing vinyl phenyl organic silicon resin, which has a structural general formula as follows: [ Me ] 3 SiO 0.5 ] m [MeHSiO] n [MeViSiO] q [PhSiO 1.5 ] t [(PO) 1/3 (CH 2 OMe 2 SiC 3 H 6 NHCOO 0.5 )] p (ii) a Wherein m is an integer of 1-10, n is an integer of 1-15, q is an integer of 1-10, t is an integer of 5-30, and p is an integer of 1-3, and the preparation method comprises the steps of taking an alkoxy silane mixture as a raw material, and carrying out hydrolysis-condensation reaction under the common catalysis of hydrogen type strong-acid cation exchange resin and p-toluenesulfonic acid,PO(CH 2 OMe 2 SiC 4 H 8 NCO) 3 And end capping reaction. The invention overcomes the defects of poor storage viscosity stability and poor electrical insulation performance caused by high hydroxyl content in the silicone resin prepared by the prior art, the silicone resin prepared by the invention has lower content of the silicone hydroxyl and good viscosity stability in storage period, and the single-component addition type silicone impregnating varnish prepared by taking the silicone resin as the raw material has excellent electrical insulation performance after curing.)

1. A low-hydroxyl hydrogen-containing vinyl phenyl organosilicon resin comprises organosilicon chain segments containing hydrogen groups, vinyl and phenyl, and the organosilicon chain segments are prepared by the following stepsCharacterized in that the silicone segment comprises [ (PO)_1/3(CH₂OMe₂SiC₃H₆NHCOO_0.5)]A group.

2. The low hydroxyl hydrogen-containing vinyl phenyl silicone resin as claimed in claim 1, wherein the structural formula of the silicone resin is as follows:

[Me₃SiO_0.5]_m[MeHSiO]_n[MeViSiO]_q[PhSiO_1.5]_t[(PO)_1/3(CH₂OMe₂SiC₃H₆NHCOO_0.5)]_p；

wherein m is an integer of 1 to 10, n is an integer of 1 to 15, q is an integer of 1 to 10, t is an integer of 5 to 30, and p is an integer of 1 to 3.

3. The low-hydroxyl hydrogen-containing vinyl phenyl silicone resin as claimed in claim 2, wherein m is an integer from 3 to 8, n is an integer from 5 to 12, q is an integer from 3 to 8, t is an integer from 6 to 25, and p is an integer from 1 to 2; the number average molecular weight is 2000-6000, the weight average molecular weight is 3000-9500, and the molecular weight distribution coefficient is not more than 2.0.

4. A method for preparing the low hydroxyl hydrogen-containing vinyl phenyl silicone resin as claimed in any one of claims 1 to 3, which is characterized by comprising the following steps: silane mixture is used as raw material, organic silicon hydrolysate is obtained through hydrolysis-condensation reaction under the catalysis of mixed acid, and then the organic silicon hydrolysate is mixed with PO (CH)₂OMe₂SiC₃H₆NCO)₃And (3) reacting to obtain the compound.

5. The method for preparing the low-hydroxyl hydrogen-containing vinyl phenyl silicone resin according to claim 4, characterized in that the method comprises the following steps:

the preparation method comprises the following steps:

(1) adding water, a mixed acid catalyst and an organic solvent into a reactor, dropwise adding a metered silane mixture, heating to 30-70 ℃, reacting for 3-8 hours, and cooling to room temperature;

(2) filtering and separating the reaction liquid obtained in the step (1) to obtain an organic phase, washing the organic phase to be neutral, removing the organic solvent, and further heating for condensation reaction under a vacuum condition to obtain an organic silicon hydrolysate;

(3) the organosilicon hydrolyzate produced in step (2) is admixed with a metered amount of PO (CH)₂OMe₂SiC₃H₆NCO)₃Mixing under the protection of nitrogen, and stirring and reacting for 3-8 h at the temperature of 30-80 ℃;

(4) and (4) heating the reaction liquid obtained in the step (3) in vacuum to remove low-boiling-point substances to obtain the low-hydroxyl hydrogen-containing vinyl phenyl organic silicon resin.

6. The method of claim 4 or 5, wherein the silane mixture is a composition comprising phenyl T units, methyl hydrogen D units, methyl vinyl D units, and trimethyl M units.

7. The method for preparing the low-hydroxyl hydrogen-containing vinyl phenyl organosilicon resin according to claim 6, wherein the phenyl T unit is phenyl trimethoxysilane or phenyl triethoxysilane; the methyl hydrogen D unit is methyl hydrogen dimethoxy silane or methyl hydrogen diethoxy silane; the methylvinyl D unit is methylvinyldimethoxysilane or methylvinyldiethoxysilane; the trimethyl M unit is trimethyl methoxy silane or trimethyl ethoxy silane.

8. The method for preparing the low-hydroxyl hydrogen-containing vinyl phenyl organosilicon resin according to claim 7, wherein the molar ratio of the phenyl T unit, the methyl hydrogen D unit, the methyl vinyl D unit and the trimethyl M unit is 2-6: 1-3: 1: 0.5-2.

9. The method for preparing the low-hydroxyl hydrogen-containing vinyl phenyl organosilicon resin according to claim 4 or 5, wherein the molar ratio of water to hydrolyzable groups in the silane mixture is 2-8: 1;

the mixed acid catalyst is a mixture of hydrogen type strong acid cation exchange resin and p-toluenesulfonic acid; wherein the mass ratio of the hydrogen type strong-acid cation exchange resin to the silane mixture is 10-20: 100, the mass ratio of the p-toluenesulfonic acid to the silane mixture is 1-5: 100.

10. the method for preparing low-hydroxyl hydrogen-containing vinyl phenyl silicone resin as claimed in claim 4 or 5, wherein the PO (CH)₂OMe₂SiC₃H₆NCO)₃The mass ratio of the organic silicon hydrolysate to the organic silicon hydrolysate is 5-10: 100.

Technical Field

The invention relates to the technical field of organic silicon resin, in particular to low-hydroxyl hydrogen-containing vinyl phenyl organic silicon resin and a preparation method thereof.

Background

The organic silicon resin is polyorganosiloxane with a highly cross-linked network structure, which takes Si-O-Si as a main chain and connects organic groups on silicon atoms. According to different crosslinking and curing modes, the method can be divided into condensation type and addition type. The condensed type organic silicon resin is a solid product which is obtained by further condensing and crosslinking a silicon resin prepolymer containing Si-OH, Si-OR and other groups under the action of a catalyst OR under heating; the addition type organic silicon resin is crosslinked by the hydrosilylation addition reaction of siloxane containing Si-Vi bonds and siloxane containing Si-H bonds under the action of a catalyst.

Compared with condensed type organic silicon resin, the addition type organic silicon resin has the advantages of no by-product generated in the curing process, small shrinkage, short production period and the like. For example, chinese patent publication No. CN 105295720 a discloses an addition type silicone impregnating varnish, and a preparation method and application thereof, wherein the addition type silicone impregnating varnish is prepared by mixing and blending a silicone resin prepolymer a (containing vinyl siloxane), a silicone resin prepolymer B (containing hydrogen siloxane), a catalyst and an inhibitor. The main disadvantage of the technical scheme is that the organic silicon impregnating varnish consists of two main components, namely two-component organic silicon impregnating varnish, and the industrial preparation cost of the organic silicon impregnating varnish is high and the process is complex; further, as disclosed in chinese patent publication No. CN 101070386 a, a method for preparing a single-component addition-crosslinkable silicone resin containing H-siloxane, which is composed of a single-component silicone resin, has disadvantages that the raw materials are all chlorosilane mixtures, a large amount of HCl is released during hydrolysis, environmental pollution and equipment corrosion are easily caused, and the reaction is severe and difficult to control. Therefore, there is a need to develop a method for preparing a one-component addition type silicone resin that is more environmentally friendly, less costly, and simpler in process.

Addition type silicone resins are commonly used for impregnating coils and parts of electric machines and appliances, and are the main insulating materials of windings of electric products. The organic silicon resin is usually prepared by a hydrolytic polycondensation method, silicon hydroxyl generated by hydrolysis is difficult to be completely polycondensed, and the silicon hydroxyl can generate further polycondensation reaction in the storage process of 80 ℃, so that the viscosity of the product is obviously increased, and the requirement of a Vacuum Pressure Impregnation (VPI) process on high stability of the viscosity of the silicon resin cannot be met. Residual hydroxyl groups during curing can generate small molecules such as water, alcohol or hydrogen, and the insulating property of the resin is reduced. The prepared low-hydroxyl-content organic silicon resin can obviously improve the storage viscosity stability, reduce the formation of small molecules in the curing process, avoid bubbles and blisters and improve the electrical insulation performance. In the prior art (publication No. CN108219137A, CN108329474A Chinese patent document), trimethylchlorosilane is adopted to carry out end capping reaction on residual silicon hydroxyl in organic silicon resin, hydrogen chloride is generated in the process, the system is strongly acidic, and the post treatment is complicated. Therefore, the technology for eliminating the silicon hydroxyl is environment-friendly, non-corrosive and simple in post-treatment, and has important significance.

Disclosure of Invention

The invention provides the low-hydroxyl hydrogen-containing vinyl phenyl organic silicon resin, aiming at overcoming the defects that the hydrolytic silicon resin in the prior art has high hydroxyl content, so that the viscosity stability of the hydrolytic silicon resin during the storage period is poor, the electrical insulation performance of the hydrolytic silicon resin is poor, and the post-treatment of the existing means for eliminating the hydroxyl is more complicated and is not environment-friendly.

In order to achieve the purpose, the invention is realized by the following technical scheme:

a low hydroxyl hydrogen-containing vinyl phenyl silicone resin comprises a silicone chain segment containing hydrogen, vinyl and phenyl, the silicone chain segment contains [ (PO)_1/3(CH₂OMe₂SiC₃H₆NHCOO_0.5)]A group.

The silicone resin segment in the present invention contains [ (PO)_1/3(CH₂OMe₂SiC₃H₆NHCOO_0.5)]Group whose principle is that the silicon hydroxyl group at the end of the silicone resin is bonded to PO (CH)₂OMe₂SiC₃H₆NCO)₃The isocyanate group in (b) reacts, thereby effectively reducing the content of the silicon hydroxyl group. PO (CH) in the invention₂OMe₂SiC₃H₆NCO)₃Because of a plurality of isocyanate groups in a single molecule, the reaction activity between the organic silicon resin and hydroxyl groups is higher than that of the traditional isocyanate with a single reaction functional group, so that the hydroxyl groups in the organic silicon resin can be reacted more thoroughly.

PO (CH) in the invention₂OMe₂SiC₃H₆NCO)₃Compared with the existing polyisocyanate, the organic silicon modified phosphorus-containing polyisocyanate has more excellent heat resistance; by using PO (CH) of the invention₂OMe₂SiC₃H₆NCO)₃As a silicon hydroxyl scavenger, the prepared silicon resin contains elements such as silicon, phosphorus, nitrogen and the like, has a synergistic flame retardant effect and endows the silicone impregnated resin with good flame retardancy; meanwhile, phosphorus is introduced into the silicon resin, so that the adhesive force of the silicon resin and the bonding base material can be improved.

Preferably, the structural general formula of the silicone resin is as follows:

[Me₃SiO_0.5]_m[MeHSiO]_n[MeViSiO]_q[PhSiO_1.5]_t[(PO)_1/3(CH₂OMe₂SiC₃H₆NHCOO_0.5)]_p(ii) a Wherein m is an integer of 1 to 10, n is an integer of 1 to 15, q is an integer of 1 to 10, t is an integer of 5 to 30, and p is an integer of 1 to 3.

Preferably, m in the structural general formula is an integer of 3-8, n is an integer of 5-12, q is an integer of 3-8, t is an integer of 6-25, and p is an integer of 1-2; the number average molecular weight is 2000-6000, the weight average molecular weight is 3000-9500, and the molecular weight distribution coefficient is not more than 2.0.

A method for preparing the low-hydroxyl hydrogen-containing vinyl phenyl organic silicon resin as described above, which comprises the following steps: silane mixture is used as raw material, organic silicon hydrolysate is obtained through hydrolysis-condensation reaction under the catalysis of mixed acid, and then the organic silicon hydrolysate is mixed with PO (CH)₂OMe₂SiC₃H₆NCO)₃And (3) reacting to obtain the compound.

Preferably, the preparation method comprises the following specific steps:

the preparation method comprises the following steps:

(1) adding water, a mixed acid catalyst and an organic solvent into a reactor, dropwise adding a metered silane mixture, heating to 30-70 ℃, reacting for 3-8 hours, and cooling to room temperature;

(2) filtering and separating the reaction liquid obtained in the step (1) to obtain an organic phase, washing the organic phase to be neutral, removing the organic solvent, and further heating for condensation reaction under a vacuum condition to obtain an organic silicon hydrolysate;

(3) the organosilicon hydrolyzate produced in step (2) is admixed with a metered amount of PO (CH)₂OMe₂SiC₃H₆NCO)₃Mixing under the protection of nitrogen, and stirring and reacting for 3-8 h at the temperature of 30-80 ℃;

(4) and (4) heating the reaction liquid obtained in the step (3) in vacuum to remove low-boiling-point substances to obtain the low-hydroxyl hydrogen-containing vinyl phenyl organic silicon resin.

Preferably, the silane mixture in step (1) is a composition comprising phenyl T units, methyl hydride D units, methyl vinyl D units and trimethyl M units.

Preferably, the phenyl T unit in the step (1) is phenyl trimethoxy silane or phenyl triethoxy silane; the methyl hydrogen D unit is methyl hydrogen dimethoxy silane or methyl hydrogen diethoxy silane; the methylvinyl D unit is methylvinyldimethoxysilane or methylvinyldiethoxysilane; the trimethyl M unit is trimethyl methoxy silane or trimethyl ethoxy silane.

Preferably, the molar ratio of the phenyl T unit, the methyl hydrogen D unit, the methyl vinyl D unit and the trimethyl M unit in the step (1) is 2-6: 1-3: 1: 0.5-2.

More preferably, in the step (1), the molar ratio of the phenyl T unit, the methyl hydrogen D unit, the methyl vinyl D unit and the trimethyl M unit is 2.5-3.5: 1.3-1.6: 1: 1.2-1.6.

The silane mixture with different proportions can be used for preparing organic silicon resin with different group contents and different number average molecular weights. The silane mixture is added dropwise in a time period of not more than 30 min.

Preferably, the molar ratio of the water to the hydrolyzable groups in the silane mixture in step (1) is 2 to 8:1, and more preferably 3 to 5:1.

Preferably, the mixed acid catalyst in the step (1) is a mixture of hydrogen type strong-acid cation exchange resin and p-toluenesulfonic acid; wherein the mass ratio of the hydrogen type strong-acid cation exchange resin to the silane mixture is 10-20: 100, the mass ratio of the p-toluenesulfonic acid to the silane mixture is 1-5: 100.

preferably, in step (1), the hydrogen-type strongly acidic ion exchange resin may be a 001 × 7-type hydrogen-type strongly acidic cation exchange resin as it is, or a 001 × 7-type sodium-type strongly acidic cation exchange resin may be treated with sodium chloride, sodium hydroxide, or hydrochloric acid to obtain a hydrogen-type strongly acidic cation exchange resin, and the catalytic effect is the same.

The alkoxy silane is hydrolyzed by adopting catalysts such as hydrochloric acid, sulfuric acid and the like to convert SiOR groups into SiOH groups and promote the condensation polymerization between Si-OH groups, but the acid catalysts can inevitably introduce more inorganic anions into a product to influence the electrical insulation performance of the silicon resin, and a reaction system is strong in acidity and severely corrodes equipment. The hydrogen type strong acid ion exchange resin is used as a catalyst, can not introduce miscellaneous groups (can not pollute products) in the reaction process, has low corrosion to equipment, has simple post-treatment, and is a novel catalyst which is environment-friendly. The hydrogen type strong acid cation exchange resin has excellent catalytic performance for silane hydrolysis reaction, but is limited by the pore diameter size, and has poor catalytic performance for condensation polymerization reaction of silicon resin prepolymer. The p-toluenesulfonic acid has certain catalytic performance on the hydrolysis and polycondensation of silane, and the hydrogen type strong-acid cation exchange resin and the p-toluenesulfonic acid can be used together to effectively reduce the dosage of the p-toluenesulfonic acid and reduce the washing times.

Further preferably, the reaction temperature in the step (1) is 60-70 ℃, and the reaction is carried out for 3-8 hours to enhance the hydrolysis and condensation reaction.

Preferably, the organic solvent in the step (1) is at least one selected from benzene, toluene and petroleum ether with a boiling range of 60-90, and the mass of the organic solvent is 0.5-1 time of that of the silane mixture.

Preferably, the vacuum pressure in the step (2) is less than 100hPa, the condensation reaction temperature is 100-150 ℃, and the time is 2-4 h.

Further preferably, the vacuum pressure in the step (2) is less than 50hPa, the temperature of the condensation reaction is 120-150 ℃, and the time is 2-4 h.

Preferably, PO (CH) in step (3)₂OMe₂SiC₃H₆NCO)₃The mass ratio of the organic silicon hydrolysate to the organic silicon hydrolysate is 5-10: 100.

preferably, PO (CH) in step (3)₂OMe₂SiC₃H₆NCO)₃The preparation method is as follows:

under the protection of nitrogen, excess dimethyl aminopropyl methoxysilane and trihydroxymethyl phosphorus oxide react according to the molar ratio of 5:1 in a toluene solvent, and PO (CH) is obtained through methanol-removing ester exchange reaction₂OMe₂SiC₃H₆NH₂)₃(ii) a PO (CH)₂OMe₂SiC₃H₆NH₂)₃Reacting with bis (trichloromethyl) carbonate in the presence of triethylamine to obtain a target product PO (CH)₂OMe₂SiC₃H₆NCO)₃The reaction equation is shown in formula (1).

Formula (1):

compared with the prior art, the invention has the following advantages:

(1) the invention provides a single-component addition type organic silicon resin which is a single-component crosslinkable polymer containing hydrogen, vinyl and phenyl groups, and has low content of residual silicon hydroxyl;

(2) the invention also provides a preparation method of the single-component addition type organic silicon resin, which adopts an alkoxy silane mixture as a raw material, and the alkoxy silane mixture is subjected to the hydrolysis polycondensation reaction catalyzed by the hydrogen type strong-acid ion exchange resin and the p-toluenesulfonic acid together, so that the reaction process is mild and controllable, and is beneficial to environmental protection and equipment corrosion prevention; the vacuum heating condensation process is adopted, so that the contents of oligomers and silicon hydroxyl in the organic silicon resin are effectively reduced; the preparation process is simple and the cost is low;

(3) the invention also provides PO (CH)₂OMe₂SiC₃H₆NCO)₃The silicon hydroxyl eliminating agent has good reaction effect, no corrosion and convenience and easiness;

(4) the low-hydroxyl hydrogen-containing vinyl phenyl silicone resin provided by the invention has good viscosity stability in a storage period of 80 ℃ and good electrical insulation after curing.

Drawings

FIG. 1 shows PO (CH) in example 1₂OMe₂SiC₃H₆NCO)₃An infrared spectrum.

FIG. 2 is the NMR spectrum of the low hydroxyl hydrogen-containing vinyl phenyl silicone resin in example 2.

FIG. 3 is the IR absorption spectrum of low-hydroxyl hydrogen-containing vinyl phenyl silicone resin in example 2.

FIG. 4 is the NMR spectrum of the hydrogen-containing vinylphenyl silicone resin in comparative example 1.

FIG. 5 is an infrared absorption spectrum of the hydrogen-containing vinylphenyl silicon resin in comparative example 1.

Detailed Description

The invention is further described with reference to the drawings and the specific embodiments. The following description of the embodiments is provided to enable any person skilled in the art to make and use the invention. The materials used in the examples are commercially available and it will be readily apparent to those skilled in the art that various modifications to these examples can be made and the generic principles described herein can be applied to other examples without the use of inventive faculty. Therefore, the present invention is not limited to the following embodiments, and those skilled in the art should make improvements and modifications within the scope of the present invention based on the disclosure of the present invention.