阅读说明：本技术 一种可化学交联固化的含氟mdq类型硅树脂及其制备方法 (Fluorine-containing MDQ type silicon resin capable of being chemically crosslinked and cured and preparation method thereof ) 是由 伍川 苏丽 董红 瞿志荣 蒋攀 荣瑞 吕叶红 邱化玉 蒋剑雄 于 2019-02-18 设计创作，主要内容包括：本发明涉及有机化学领域,为了解决有机硅树脂与有机氟树脂物理共混时存在的相容性问题以及有机氟硅树脂的交联固化性能和反应性能,本发明提出一种可化学交联固化的含氟MDQ类型硅树脂及其制备方法,以六甲基二硅氧烷和1,3-二乙烯基-1,1,3,3-四甲基二硅氧烷作为M链节来源,甲基三氟丙基二甲氧基硅烷作为D链节来源,正硅酸乙酯作为Q链节来源,乙醇-水溶液作为反应溶剂,甲苯作为萃取剂,在酸性催化剂作用下通过共水解缩合工艺制备而成。本发明合成方法简单,反应条件温和,产物容易分离回收,设备投资少,设备利用率高,易于工业化生产。本发明制备的MDQ硅树脂兼具有机硅树脂与氟树脂的优异性能,可提高手机等显示屏的抗污性能。(The invention relates to the field of organic chemistry, and aims to solve the compatibility problem existing in the physical blending of organic silicon resin and organic fluorine resin and the crosslinking curing performance and reaction performance of the organic fluorine-containing silicon resin. The synthesis method is simple, the reaction condition is mild, the product is easy to separate and recycle, the equipment investment is low, the equipment utilization rate is high, and the industrial production is easy to realize. The MDQ silicone resin prepared by the invention has the excellent performances of organic silicon resin and fluororesin, and can improve the anti-fouling performance of display screens such as mobile phones.)

1. A chemically cross-linkable curable fluorine-containing MDQ-type silicone resin, wherein the silicone resin has the structural formula (I):

wherein a =0.10 ~ 0.6.6, b =0.10 ~ 0.40, c =0.25 ~ 0.80, d =1, and (a + b)/c =0.4 ~ 2.4.4.

2. The method for preparing a chemically crosslinkable and curable fluorine-containing MDQ type silicone resin according to claim 1, wherein the silicone resin is prepared by a cohydrolytic condensation process of hexamethyldisiloxane, 1,3, 3-tetramethyl-1, 3-divinyldisiloxane, methyltrifluoropropyldimethoxysilane and ethyl orthosilicate in an ethanol-water mixed solution under the action of an acid catalyst.

3. The method for preparing the chemically cross-linkable and curable fluorine-containing MDQ-type silicone resin according to claim 2, wherein the method comprises the following steps:

1) sequentially adding deionized water, absolute ethyl alcohol, hexamethyldisiloxane, 1,3, 3-tetramethyl-1, 3-divinyl disiloxane and methyltrifluoropropyldimethoxysilane into a reaction vessel, and dropwise adding an acidic catalyst while stirring at room temperature;

2) after adding an acid catalyst, heating the mixed solution for hydrolysis, and then dropwise adding tetraethoxysilane into the mixed solution; after the tetraethoxysilane is dripped, the materials in the reaction kettle are kept to react;

3) adding methylbenzene into the materials in the reaction kettle for extraction, cooling the mixed materials to room temperature, washing the mixed materials to be neutral by using deionized water, and then adding a drying agent for drying until the materials are clear and transparent;

4) filtering the material in the step 3), performing rotary distillation on the filtrate, and removing the solvent to obtain the chemically cross-linked and solidified fluorine-containing MDQ type silicone resin.

4. The method for preparing a chemically crosslinkable curable fluorine-containing MDQ type silicone resin according to claim 3, wherein the mass ratio of the deionized water to the absolute ethanol in the step 1) is 1.0 ~ 4.5.5: 1, the mass ratio of hexamethyldisiloxane to the absolute ethanol is 0.1 ~ 0.8.8: 1, the mass ratio of hexamethyldisiloxane to 1, 3-divinyl-1, 1,3, 3-tetramethyldisiloxane is 0.75 ~ 2: 1, the mass ratio of the sum of the mass of hexamethyldisiloxane to 1, 3-divinyl-1, 1,3, 3-tetramethyldisiloxane to the mass ratio of methyltrifluoropropyldimethoxysilane is 0.1 ~ 1.5.5: 1, and the mass ratio of the acidic catalyst to the absolute ethanol is 0.05 ~ 1.0.0: 1.

5. The method of claim 3 or 4, wherein the time required for adding all of the acid catalyst selected from concentrated hydrochloric acid, acetic acid, concentrated sulfuric acid, and acidic cationic resin is 0.5 ~ 10 min.

6. The method for preparing a chemically crosslinkable curable fluorine-containing MDQ type silicone resin according to claim 3, wherein the mass ratio of tetraethoxysilane to methyltrifluoropropyldimethoxysilane in step 2) is 1.0 ~ 3.3.3: 1.

7. The method of claim 3 or 6, wherein the mixture in step 2) is hydrolyzed by heating from room temperature to 35 ~ 60 ℃ for 1 ~ 20min, the tetraethoxysilane is fed for 0.5 ~ 30min, the tetraethoxysilane is fed for 65 ~ 90 ℃ and the reaction time is 0.5 ~ 5 h.

8. The method for preparing the chemically crosslinkable and curable fluorine-containing MDQ type silicone resin according to claim 3, wherein the temperature of the reaction kettle material in the step 3) is maintained at 40 ~ 80 ℃, and the extraction time after the toluene is added is 0.25 ~ 6 h.

9. The method for preparing a chemically crosslinkable curable fluorine-containing MDQ-type silicone resin according to claim 3 or 8, wherein the mass ratio of toluene in step 3) to deionized water in step 1) is 0.8 ~ 3: 1.

10. The method for preparing the chemically crosslinkable and curable fluorine-containing MDQ type silicone resin according to claim 3, wherein the drying agent in the step 3) is one or more selected from anhydrous calcium chloride, anhydrous magnesium sulfate and anhydrous sodium sulfate, and the mass ratio of the drying agent to the toluene is 0.10 ~ 0.40.40: 1.

Technical Field

The invention relates to the field of organic polymer chemistry, in particular to fluorine-containing MDQ type silicon resin capable of being chemically crosslinked and cured and a preparation method thereof.

Background

The organic silicon resin takes Si-O bond as a main chain, has unique structure with the performances of inorganic materials and organic materials, has the basic properties of low surface tension, small viscosity-temperature coefficient, high compressibility, high gas permeability and the like, has the excellent characteristics of high and low temperature resistance, oxidation resistance stability, flame retardancy, corrosion resistance, no toxicity, no odor, physiological inertia and the like, and is widely applied to the industries of aerospace, electronics and electricity, construction, transportation, textile, food, light industry, medical treatment and the like.

Fluororesin has many unique excellent properties as compared with conventional plastics and organic polymers such as polyethylene and polypropylene. Fluororesins have excellent chemical stability, weather resistance, stain resistance, water and oil resistance, ultraviolet resistance, etc., are the best weather-resistant outdoor coatings found to date, and have been successfully used in optical fiber coatings, optical element protective coatings, packaging coatings, automobile paints, architectural coatings, textile finishes, etc. Chinese patent CN 108610479A discloses a preparation method of fluorine-containing resin, which comprises the steps of mixing perfluoropropene dimer, perfluoropropene trimer, fatty alcohol monomer, catalyst and organic solvent, reacting at 70-120 ℃ for 24-38 h, cooling, cleaning, and centrifugally dewatering to obtain hydroxyl fluororesin, wherein the resin has the performances of water resistance, solvent resistance, alkali resistance, surface antifouling property and the like, but the resin cannot be cured by a hydrosilylation method.

Fluorine and silicon are organically combined in the same resin by the fluorine-silicon resin, the respective advantages of fluorine element and silicon element are exerted, and the novel material has excellent comprehensive performance. Chinese patent CN102924734A discloses that organosilicon resin and organic fluororesin are used as raw materials, and are catalyzed and condensed to generate fluorosilicone resin under the action of a coupling agent, and the obtained product can be cured to form a film which can be used as a coating agent, can provide water repellency when being applied to fabric after-treatment, does not lose the moisture permeability required by textiles, and can not be cured in a hydrosilylation manner.

As is well known, the silicone material and the organofluorosilicone material are mainly cross-linked and cured by three ways, namely, a condensation reaction, a cross-linking reaction initiated by a peroxide compound and a hydrosilylation reaction, and the condensation reaction and the cross-linking reaction initiated by the peroxide compound both have the problem of size change before and after curing to different degrees, and in addition, the cross-linking reaction initiated by the peroxide compound usually needs to be carried out at a high temperature of more than 150 ℃, which brings inconvenience to the cross-linking and curing process of the silicone material and the organofluorosilicone material. The hydrosilylation crosslinking reaction can be carried out at room temperature or at an elevated temperature, and the crosslinking reaction speed increases with the temperature; another significant advantage of the hydrosilylation cross-linking reaction is that the material does not change in size before and after the cross-linking reaction occurs, especially without causing porosity or dimensional shrinkage of the material as does the condensation reaction and the cross-linking reaction initiated by the peroxide compound.

MQ silicone resin is composed of monofunctional chain links (R)₃SiO_1/2I.e. M mer) and tetrafunctional mer (SiO)_4/2，i.e.Q-block) are more specific organic/inorganic hybrid polyorganosiloxanes. With the difference of molar ratio of M chain unit to Q chain unit (i.e. n (M)/n (Q)) in MQ value, MQ silicone resin has different relative molecular mass, and presents different states from viscous fluid to powdery solid, and its physical properties such as density, transparency, viscosity, softening point, viscosity increasing property, oleophylic and hydrophilic properties are changed. MDQ silicone is one of MQ silicone, which is composed of M chain units with single functionality and D chain units (R) with double functionality₂SiO_2/2I.e. D units) and tetrafunctional Q units, by cohydrolysis-polycondensation reaction to form silicon having a core-shell structureKetone esters can be used in the fields of cosmetics, semiconductor device packaging, building sealants and the like. Chinese invention patent CN102898648 discloses a preparation method of chemically crosslinkable MDQ type phenyl vinyl silicone resin, which uses hexamethyldisiloxane and 1, 3-divinyl-1, 1,3, 3-tetramethyldisiloxane as end capping agents (namely M chain link sources), methyl phenyl diethoxysilane as D chain link sources, ethyl orthosilicate as Q chain link sources, ethanol as a solvent, and hydrolysis and condensation are carried out under the catalysis of hydrochloric acid to obtain the MDQ silicone resin with the refractive index of 1.46-1.50, and the resin can be cured through hydrosilylation, but the molecule does not contain fluorine atoms, so that the antifouling property is poor.

Disclosure of Invention

In order to solve the problem that the resin generates bubbles or shrinks in size in the curing process, the invention provides the fluorine-containing MDQ type silicone resin capable of being chemically crosslinked and cured and the preparation method thereof.

The invention is realized by the following technical scheme: a chemically cross-linkable curable fluorine-containing MDQ-type silicone resin, the silicone resin having a structural formula as shown in (I):

in the formula: me represents a methyl group, Vi represents a vinyl group, and a, b, c and d each represent a trimethylsiloxy chain unit in the resin molecule (Me)₃SiO_1/2-) relative moles of dimethylvinylsiloxy units (Me)₂ViSiO_1/2-) relative moles of methyltrifluoropropylsiloxy mer (Me (CF)₃CH₂CH₂)SiO_2/2-) relative moles and Q mer (SiO)_4/2) The relative mole number of (a) is 0.10 to 0.6, b is 0.10 to 0.40, c is 0.25 to 0.80, d is 1, and (a + b)/c is 0.4 to 2.4.

In order to obtain the organofluorosilicone resin containing fluorine atoms and silicon atoms in molecules, wherein the molecules of the organofluorosilicone resin also contain a silicon vinyl unsaturated functional group, and further can be crosslinked and cured by utilizing a silicon hydrogen addition reaction mode between the silicon vinyl functional group and active silicon hydrogen bonds to avoid bubbles or size shrinkage in the curing process of the resin, the preparation method of the fluorine-containing MDQ type silicon resin capable of being chemically crosslinked and cured is prepared by taking hexamethyldisiloxane and 1,1,3, 3-tetramethyl-1, 3-divinyl disiloxane as M chain link sources, methyl trifluoropropyl dimethoxysilane as D chain link sources, tetraethoxysilane as Q chain link sources, ethanol-water mixed solution as a reaction solvent and carrying out cohydrolysis condensation process under the action of an acid catalyst.

The preparation method comprises the following steps:

1) sequentially adding deionized water, absolute ethyl alcohol, hexamethyldisiloxane, 1,3, 3-tetramethyl-1, 3-divinyl disiloxane and methyltrifluoropropyldimethoxysilane into a reaction vessel, and dropwise adding an acidic catalyst while stirring at room temperature;

the mass ratio of the deionized water to the absolute ethyl alcohol is 1.0-4.5: 1; the mass ratio of hexamethyldisiloxane to absolute ethyl alcohol is 0.1-0.8: 1; the mass ratio of hexamethyldisiloxane to 1, 3-divinyl-1, 1,3, 3-tetramethyldisiloxane is 0.75-2: 1; the mass ratio of the sum of the mass of hexamethyldisiloxane and 1, 3-divinyl-1, 1,3, 3-tetramethyldisiloxane to the mass of methyltrifluoropropyldimethoxysilane is 0.1-1.5: 1; the mass ratio of the acidic catalyst to the absolute ethyl alcohol is 0.05-1.0: 1.

Preferably, the time required for adding all the acid catalyst is 0.5-10 min, and the acid catalyst is selected from one of concentrated hydrochloric acid, acetic acid, concentrated sulfuric acid and acid cation exchange resin. Hydrochloric acid with mass fraction of more than 20% is called concentrated hydrochloric acid, and concentrated sulfuric acid refers to sulfuric acid with mass fraction of more than or equal to 70%.

2) After adding an acid catalyst, heating the mixed solution for hydrolysis, and then dropwise adding tetraethoxysilane into the mixed solution; after the tetraethoxysilane is dripped, the materials in the reaction kettle are kept to react;

the mass ratio of the tetraethoxysilane to the methyltrifluoropropyldimethoxysilane is 1.0-3.3: 1.

And heating the mixed solution from room temperature for l-20 min to 35-60 ℃ for hydrolysis, wherein the charging time of tetraethoxysilane is 0.5-30 min, the reaction temperature after tetraethoxysilane is added is 65-90 ℃, and the reaction time is 0.5-5 h.

3) Adding methylbenzene into the materials in the reaction kettle for extraction, cooling the mixed materials to room temperature, washing the mixed materials to be neutral by using deionized water, and then adding a drying agent for drying until the materials are clear and transparent;

preferably, the temperature of the materials in the reaction kettle is maintained at 40-80 ℃, and the extraction time after toluene is added is 0.25-6 h;

preferably, the mass ratio of the toluene to the deionized water in the step 1) is 0.8-3: 1;

preferably, the drying agent is selected from one or more of anhydrous calcium chloride, anhydrous magnesium sulfate and anhydrous sodium sulfate, and the mass ratio of the drying agent to the toluene is as follows: 0.10-0.40: 1;

4) filtering the materials in the step 3) to remove salt, performing rotary distillation on the filtrate, and removing the solvent to obtain colorless and transparent fluorine-containing MDQ type silicone resin capable of being chemically crosslinked and cured.

The fluorine-containing MDQ type silicon resin capable of being chemically crosslinked and cured disclosed by the invention not only contains fluorine atoms and silicon atoms, but also contains silicon vinyl functional groups capable of participating in crosslinking reaction, and can be crosslinked and cured with components containing silicon-hydrogen bonds under the action of a platinum complex catalyst through a silicon-hydrogen addition reaction mechanism.

The reaction mechanism of the present invention is as follows:

the formula (1) and the formula (2) respectively show that hexamethyldisiloxane and 1, 3-divinyl-1, 1,3, 3-tetramethyldisiloxane are hydrolyzed under the action of an acid catalyst to generate corresponding silanol with single end functionality (M chain), the formula (3) shows that methyltrifluoropropyldimethoxysilane is hydrolyzed under the action of an acid catalyst to generate silanol with bifunctionality (D chain) and containing methyltrifluoropropyl functional groups, the formula (4) shows that tetraethoxysilane is hydrolyzed under the action of an acid catalyst to generate silanol with tetrafunctionality (Q chain), and the formula (5) shows that the silanol generated by hydrolysis is further condensed and polymerized under the acid condition to generate MDQ type silicone resin containing silicon vinyl and methyltrifluoropropyl functional groups.

Compared with the prior art, the invention has the beneficial effects that:

(1) the fluorine-containing MDQ resin with a uniform and stable structure can be obtained by taking trifluoropropyl-functionalized siloxane containing fluorine atoms as a reaction raw material and preparing the organic fluorine-silicon resin containing fluorine elements and silicon elements in molecules through cohydrolysis polycondensation, so that the problems of poor compatibility and phase separation existing in the preparation of the organic fluorine-silicon material by physically blending fluorine resin and silicon resin are solved;

(2) the prepared fluorine-containing MDQ resin molecule contains active silicon vinyl functional groups which can participate in reaction, and the resin can be crosslinked and cured under the action of a peroxide compound vulcanizing agent, and can also be subjected to hydrosilylation reaction with a compound or a polymer containing active silicon hydrogen bonds under the action of a hydrosilylation catalyst, so that the resin can be used as a downstream reaction intermediate or a reinforcing filler, and gaps or cracks are avoided while the mechanical property of the resin reinforced organosilicon composite material is improved;

(3) the synthesis method is simple, the reaction condition is mild, the product is easy to separate and recycle, the equipment investment is low, the equipment utilization rate is high, and the industrial production is easy to realize.

Drawings

FIG. 1 is a nuclear magnetic hydrogen spectrum of a chemically cross-linkable curable fluorine-containing MDQ-type silicone resin synthesized in example 1 of the present invention;

FIG. 2 is an infrared spectrum of a chemically cross-linkable curable fluorine-containing MDQ-type silicone resin synthesized in example 1 of the present invention;

FIG. 3 is a nuclear magnetic silicon spectrum of chemically cross-linkable cured fluorine-containing MDQ-type silicone resin synthesized in example 1 of the present invention.

Detailed Description

The present invention is further illustrated by the following examples, which are not intended to limit the scope of the invention, and the starting materials used in the examples are commercially available or can be prepared by conventional methods.