CN113004526B - Alkoxy-terminated liquid fluorosilicone rubber, and preparation method and application thereof - Google Patents

Alkoxy-terminated liquid fluorosilicone rubber, and preparation method and application thereof Download PDF

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CN113004526B
CN113004526B CN202110423930.8A CN202110423930A CN113004526B CN 113004526 B CN113004526 B CN 113004526B CN 202110423930 A CN202110423930 A CN 202110423930A CN 113004526 B CN113004526 B CN 113004526B
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alkoxy
fluorosilicone rubber
methyl radical
terminated
liquid fluorosilicone
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CN113004526A (en
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张孝阿
张猛
蒲倩
刘润竹
王成忠
江盛玲
史翎
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Beijing University of Chemical Technology
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    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
    • C08G77/00—Macromolecular compounds obtained by reactions forming a linkage containing silicon with or without sulfur, nitrogen, oxygen or carbon in the main chain of the macromolecule
    • C08G77/04—Polysiloxanes
    • C08G77/38—Polysiloxanes modified by chemical after-treatment
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J11/00—Features of adhesives not provided for in group C09J9/00, e.g. additives
    • C09J11/02—Non-macromolecular additives
    • C09J11/04—Non-macromolecular additives inorganic
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J11/00—Features of adhesives not provided for in group C09J9/00, e.g. additives
    • C09J11/02—Non-macromolecular additives
    • C09J11/06—Non-macromolecular additives organic
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J183/00—Adhesives based on macromolecular compounds obtained by reactions forming in the main chain of the macromolecule a linkage containing silicon, with or without sulfur, nitrogen, oxygen, or carbon only; Adhesives based on derivatives of such polymers
    • C09J183/04—Polysiloxanes
    • C09J183/08—Polysiloxanes containing silicon bound to organic groups containing atoms other than carbon, hydrogen, and oxygen
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
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Abstract

The invention relates to the field of high polymer materials, in particular to alkoxy-terminated liquid fluorosilicone rubber, and a preparation method and application thereof. According to the alkoxy-terminated liquid fluorosilicone rubber provided by the invention, a plurality of alkoxy groups are introduced at the tail end of the molecular chain of the liquid fluorosilicone rubber, so that the functionality and the crosslinking reactivity of the liquid fluorosilicone rubber are greatly improved. According to the preparation method provided by the invention, alkoxy is introduced into the terminal group of the polymer through dehydrogenation condensation reaction of alpha, omega-hydroxyl-terminated polymethyl trifluoropropyl siloxane and hydrogen-containing alkoxy silane; the reaction requires low temperature and short time, the used catalyst and solvent can be recycled, the post-treatment process is simple, and the method is suitable for industrial production.

Description

Alkoxy-terminated liquid fluorosilicone rubber, and preparation method and application thereof
Technical Field
The invention relates to the field of high polymer materials, in particular to alkoxy-terminated liquid fluorosilicone rubber, and a preparation method and application thereof.
Background
Among a plurality of liquid rubbers, the liquid fluorosilicone rubber has excellent high temperature resistance and fuel oil resistance, so that the fluorosilicone sealant is widely applied to sealing of an oil tank of an aircraft engine. It is known that the oil resistance of fluorosilicone rubbers increases with increasing fluorine content. The fluorosilicone rubber can be divided into two types, namely polymethyl trifluoropropyl siloxane and polydimethyl methyl trifluoropropyl siloxane, according to the difference of the main chain structure, wherein the former contains 100% of trifluoropropyl units, is called as 'fluorosilicone 100' for short, has more excellent fuel oil resistance, and can not be replaced when being applied in an extreme oil resistant environment. Taking alpha, omega-terminal hydroxyl polymethyl trifluoropropyl siloxane (liquid fluorine silicon 100) as an example, the trifluoropropyl has larger steric hindrance, and can shield the terminal hydroxyl of the polymer, so that the activity and the crosslinking reactivity of the polymer are greatly reduced, and the polymer can only be used for preparing the single-component deacidification type room temperature vulcanized sealant with high catalytic activity and is dominant in the market. However, the release of acidic small molecules during vulcanization can cause corrosion of the sealing substrate, thereby limiting the application. When a dehydrogenation type vulcanization system is adopted, a large amount of bubbles are generated during vulcanization of the sealant, so that the mechanical property and the sealing property are deteriorated; when a dealcoholization type vulcanization system is adopted, the reaction speed is very low, an excessive amount of a crosslinking agent such as tetraethyl orthosilicate (TEOS) is generally required to be added, and the removed small molecular alcohol can cause reversion, namely the alcohol can attack a network crosslinking structure of vulcanized rubber at high temperature to cause degradation, so that the high-temperature resistance is not good. On the other hand, when the content of the trifluoropropyl unit in the polymer structure is reduced, for example, to 66%, 50%, 30%, etc., good crosslinking reactivity can be obtained, but the fluorine content is also greatly reduced, resulting in deterioration of oil resistance thereof, which limits the application.
The information disclosed in this background section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.
Disclosure of Invention
In order to solve the above problems, the present invention provides an alkoxy-terminated liquid fluorosilicone rubber, a preparation method and applications thereof. According to the alkoxy-terminated liquid fluorosilicone rubber provided by the invention, the end group is terminated by alkoxy, the shielding effect of trifluoropropyl is reduced by increasing the distance between the alkoxy and the trifluoropropyl, and the number of reactive end groups is increased, so that the end group reactivity of the liquid fluorosilicone rubber is greatly improved. After vulcanization, the vulcanized rubber still has high fluorine content and excellent oil resistance and other properties. According to the preparation method provided by the invention, alkoxy is introduced into the terminal group of the polymer through dehydrogenation condensation reaction of alpha, omega-hydroxyl-terminated polymethyl trifluoropropyl siloxane and hydrogen-containing alkoxy silane; the reaction requires low temperature and short time, the used catalyst and solvent can be recycled, the post-treatment process is simple, and the method is suitable for industrial production.
In order to achieve the purpose, the invention adopts the following technical scheme:
an alkoxy-terminated liquid fluorosilicone rubber has a structure shown in formula 1:
Figure BDA0003029072220000021
wherein n is an integer of 4 to 150, a is 0 or 1, R is C(1-12)Alkyl radical, R1Is C(1-5)Alkyl radical, R2Is C(1-5)An alkyl group.
According to the invention, the value of n is determined by the raw materials, and the liquid fluorosilicone rubber raw material has better fluidity within the range of 4-150.
According to the invention, n is preferably 4, 54 and 78.
According to the invention, R is preferably methyl.
According to the invention, preferably, R1Is methyl.
According to the invention, preferably, R2Is methyl or ethyl.
According to the invention, a is preferably 0 or 1.
According to the present invention, preferably, the present invention provides an alkoxy-terminated liquid fluorosilicone rubber, wherein the compound of formula 1 is selected from
In Table 1
Figure BDA0003029072220000022
Figure BDA0003029072220000031
According to the present invention, it is preferable that the number average molecular weight (Mn) of an alkoxy-terminated liquid fluorosilicone rubber is 930 to 13900.
According to the present invention, it is preferable that the number average molecular weight (Mn) of an alkoxy terminated liquid fluorosilicone rubber is 930, 13700 to 13900 or 9450 to 9600.
According to the present invention, it is preferable that an alkoxy-terminated liquid fluorosilicone rubber has number average molecular weights (Mn) of 930, 13800.
The invention also provides a preparation method of the alkoxy-terminated liquid fluorosilicone rubber, which comprises the following steps:
Figure BDA0003029072220000032
wherein: n is an integer of 4 to 150, R is C(1-12)Alkyl, a is 0 or 1, R1Is C(1-5)Alkyl radical, R2Is C(1-5)An alkyl group.
The cat is called catalyst, catalyst.
According to the present invention, preferably, a method for preparing an alkoxy-terminated liquid fluorosilicone rubber comprises the steps of:
(1) end capping reaction:
under the protection of inert gas, uniformly mixing alpha, omega-hydroxyl-terminated polymethyl trifluoropropyl siloxane, a catalyst and a solvent, heating, injecting hydrogen-containing alkoxy silane into the system for dehydrogenation condensation reaction, and continuing heating and reflux reaction after injection;
(2) purification of the product
And after the reaction is completed, cooling to room temperature, filtering the mixed liquid to remove the supported catalyst, and performing rotary evaporation to remove the solvent and the micromolecules in the system to obtain the alkoxy-terminated liquid fluorosilicone rubber.
In one possible implementation of the above preparation method, the α, ω -hydroxypolylmethyltrifluoropropylsiloxane has the structural formula:
Figure BDA0003029072220000041
wherein: n is an integer of 4 to 150, R is C(1-12)An alkyl group.
The structural formula of the hydrogen-containing alkoxy silane is as follows:
H-Si(R1)a(OR2)3-a
wherein: a is 0 or 1, R1Is C(1-5)Alkyl radical, R2Is C(1-5)An alkyl group.
According to the present invention, it is preferred that the inert gas in step (1) is nitrogen or argon.
According to the invention, it is preferred that the number average molecular weight (M) of the alpha, omega-hydroxy-terminated polymethyltrifluoropropylsiloxane in step (1) isn) 610, 9100 or 13500.
According to the present invention, the catalyst in step (1) preferably includes, but is not limited to, a supported catalyst containing a noble metal such as platinum, palladium, etc.
According to the present invention, it is preferred that the catalyst in step (1) comprises a supported palladium carbon catalyst having a palladium content of 3 to 6%, preferably a palladium content of 5%.
According to the invention, the amount of the catalyst added in the step (1) is preferably 0.4-2% of the mass of the alpha, omega-hydroxyl-terminated polymethyl trifluoropropyl siloxane.
According to the present invention, it is preferable that the solvent in step (1) includes, but is not limited to, petroleum ether, cyclohexane, carbon tetrachloride, toluene, dichloromethane, acetone, ethyl acetate, and tetrahydrofuran. Preferably, the solvent is tetrahydrofuran; preferably, the solvent is ultra-dry tetrahydrofuran with a purity of 99.9%.
According to the invention, the mass ratio of the solvent to the alpha, omega-hydroxyl-terminated polymethyl trifluoropropyl siloxane in the step (1) is preferably (2-10): 1.
according to the invention, the mass ratio of the solvent to the alpha, omega-hydroxyl-terminated polymethyl trifluoropropyl siloxane in the step (1) is preferably (2-3): 1
According to the invention, the molar ratio of the hydrogen-containing alkoxy silane to the alpha, omega-hydroxyl-terminated polymethyl trifluoropropyl siloxane in the step (1) is preferably (2-5): 1.
according to the invention, it is preferred that the molar ratio of the hydroalkoxysilane to the α, ω -hydroxy terminated polymethyltrifluoropropylsiloxane in step (1) is 3: 1.
according to the present invention, it is preferred that the hydroalkoxysilane in step (1) is trimethoxyhydrosilane, triethoxyhydrosilane, or methyldimethoxysilane.
According to the invention, the reflux reaction time in the step (1) is preferably 5-10 h.
According to the invention, the reflux reaction time in the step (1) is preferably 6-8 h.
According to the present invention, it is preferred that the temperature in step (1) is raised to 50 to 70 ℃ to inject the hydroalkoxysilane into the system.
According to the present invention, it is preferable that the temperature of step (1) is raised to 60 ℃ to inject the hydroalkoxysilane into the system.
According to the invention, the rotary evaporation temperature in the step (2) is preferably 100-130 ℃ and the time is 1-4 h.
According to the invention, the rotary evaporation temperature in the step (2) is preferably 120 ℃ and the time is 2-3 h.
The invention also provides application of the alkoxy end-capped liquid fluorosilicone rubber in the field of room-temperature vulcanized fluorosilicone sealants.
According to the present invention, preferably, an alkoxy-terminated liquid fluorosilicone rubber can be used for the base rubber and/or the cross-linking agent of the room temperature vulcanization fluorosilicone sealant.
The invention also provides dealcoholized room temperature vulcanized fluorosilicone sealant which comprises 104 parts of alkoxy end-capped liquid fluorosilicone rubber, 10-50 parts of fumed silica, 2-8 parts of iron oxide red and 0.2-1.5 parts of dibutyltin dilaurate.
According to the invention, the dealcoholization type room temperature vulcanization fluorosilicone sealant comprises 104 parts of alkoxy end-capped liquid fluorosilicone rubber, 10 parts of fumed silica, 3 parts of iron oxide red and 0.5 part of dibutyltin dilaurate.
According to the present invention, preferably, the alkoxy-terminated liquid fluorosilicone rubber includes, but is not limited to, trimethoxy-terminated liquid fluorosilicone rubber (M)n13800), triethoxy-terminated liquid fluorosilicone rubber (M)n13900), methyldimethoxy end-capped liquid fluorosilicone rubber (M)n13700), trimethoxy end-capped liquid fluorosilicone rubber (M)n930), triethoxy end-capped liquid fluorosilicone rubber (M)n9600), methyl groupDimethoxy terminated liquid fluorosilicone rubber (M)n9450) Trimethoxylated end-capped liquid fluorosilicone rubber (M)n9500) or more.
According to the present invention, preferably, the alkoxy-terminated liquid fluorosilicone rubber comprises trimethoxy-terminated liquid fluorosilicone rubber (M)n13800), triethoxy-terminated liquid fluorosilicone rubber (M)n13900), methyldimethoxy end-capped liquid fluorosilicone rubber (M)n13700), triethoxy terminated liquid fluorosilicone rubber (M)n9600), methyldimethoxy end-capped liquid fluorosilicone rubber (M)n9450) Trimethoxylated end-capped liquid fluorosilicone rubber (M)n9500) and trimethoxy end-capped liquid fluorosilicone rubber (M)n930) is mixed and used. Preferably, the compounding ratio is 100: 4.
the invention also provides a preparation method of the dealcoholized room temperature vulcanized fluorosilicone sealant, which comprises the following steps:
putting the gas-phase white carbon black and the iron oxide red into an oven for drying; weighing alkoxy-terminated liquid fluorosilicone rubber, fumed silica, iron oxide red and dibutyltin dilaurate, putting into a planetary stirrer, and stirring and premixing under a vacuum-pumping state; then putting the premixed sealant into a three-roll grinding machine for uniformly mixing to obtain room-temperature dealcoholized vulcanized fluorosilicone sealant sizing material; and injecting the sealant sizing material into a mold, and then strickling by using a scraper and placing to obtain the vulcanized rubber of the fluorosilicone sealant.
The present invention has not been described in detail, but is in accordance with conventional techniques in the art.
Advantageous effects
1. According to the alkoxy-terminated liquid fluorosilicone rubber provided by the invention, the end group is terminated by alkoxy, the shielding effect of trifluoropropyl is reduced by increasing the distance between the alkoxy and the trifluoropropyl, and the number of reactive end groups is increased, namely the functionality of the reactive groups is increased, so that the end group reactivity of the liquid fluorosilicone rubber is greatly improved. When the dealcoholized room temperature vulcanized sealant is applied, the sealant can be quickly vulcanized, and the vulcanized sealant has better mechanical property and bonding property.
2. The preparation method of the alkoxy-terminated liquid fluorosilicone rubber provided by the embodiment of the invention can be obtained by dehydrogenation condensation reaction of alpha, omega-hydroxyl-terminated polymethyl trifluoropropyl siloxane and hydrogen-containing alkoxy silane, and has the advantages of simple preparation route, high product yield, low temperature required by the reaction, short time, recyclable catalyst and solvent, simple post-treatment process and suitability for industrial production.
3. The alkoxy end-capped liquid fluorosilicone rubber disclosed by the invention is applied to a room-temperature vulcanized fluorosilicone sealant system, can be used as both base rubber and a cross-linking agent, and because a traditional cross-linking agent of dealcoholized sealant is not required, the base rubber and the cross-linking agent have the same structure, similar chemical properties and good compatibility. When in use, various sealants with different performances can be obtained by adjusting the proportion of the alkoxy end-capped liquid fluorosilicone rubber with different molecular weights.
Drawings
One or more embodiments are illustrated by the corresponding figures in the drawings, which are not meant to be limiting. The word "exemplary" is used exclusively herein to mean "serving as an example, embodiment, or illustration. Any embodiment described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other embodiments.
FIG. 1 is the infrared spectroscopy (FT-IR) test results for trimethoxy capped liquid fluorosilicone rubber of example 1 of this invention; 1091cm-1(Si-O-C)，1000-1100cm-1(Si-O-Si)，2849cm-1(-OCH3)。
FIG. 2 is a plot of the rheological properties of the compounds of examples 8-12 of the invention as measured by an Antopa rheometer (model: MCR-52) showing: in the state of 50% of humidity and 25 ℃ of temperature, the increasing speed of the viscosity of the mixed rubber material along with the time is in the following sequence: example 8> example 11> example 10> example 12> example 9.
FIG. 3 shows the result of the thermogravimetric analysis of the vulcanized fluorosilicone sealant of example 8 of the present invention by a thermogravimetric analyzer (TGA), and it can be seen that the initial decomposition temperature (temperature at 5% mass loss) is 373 deg.C, and the decomposition rate is the fastest at 513 deg.C and is 1.6%/. degree.C.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below, and it is obvious that the described embodiments are a part of the embodiments of the present invention, but not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention. Throughout the specification and claims, unless explicitly stated otherwise, the word "comprise", or variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated element or component but not the exclusion of any other element or component.
Furthermore, in the following detailed description, numerous specific details are set forth in order to provide a better understanding of the present invention. It will be understood by those skilled in the art that the present invention may be practiced without some of these specific details. In some embodiments, materials, elements, methods, means, and the like that are well known to those skilled in the art are not described in detail in order to not unnecessarily obscure the present invention.
In the following examples:
the alpha, omega-hydroxyl-terminated polymethyl trifluoropropyl siloxane is purchased from Weihai New chemical Co., Ltd, and has the CAS number of 68607-77-2;
trimethoxyhydrosilane is available from carbofuran, CAS number 2487-90-3;
triethoxy hydrosilane purchased from carbofuran, CAS number 998-30-1;
methyldimethoxysilane is available from carbofuran, CAS number 16881-77-9;
the palladium-carbon catalyst is purchased from Aladdin, 5% Pd and contains 40-60% H2O, CAS number 7440-05-3;
tetrahydrofuran was purchased from carbofuran with CAS number 109-99-9;
fumed silica is purchased from enoki, hydrophilic, specific surface area (BET): 380m2Particle diameter/g：7-40nm；
Iron oxide red was purchased from carbofuran under CAS number 1332-37-2;
tetraethoxysilane (TEOS) is available from carbofuran, CAS number 78-10-4;
dibutyltin dilaurate was purchased from carbofuran, CAS number 77-58-7.
Example 1
An alkoxy end-capped liquid fluorosilicone rubber is prepared by the following steps:
61g (0.1mol) of alpha, omega-hydroxyl-terminated polymethyl trifluoropropyl siloxane (with the number average molecular weight of 610), 0.4g of palladium carbon catalyst and 152.5g of tetrahydrofuran are added into a 500mL three-neck flask, the temperature is raised to 60 ℃ under the protection of nitrogen, then 36.69g (0.3mol) of trimethoxy hydrosilane is injected and the heating and the stirring are continued for 6 hours;
and cooling to room temperature, removing the palladium-carbon catalyst in the mixed solution by suction filtration through a Buchner funnel with filter paper, then carrying out rotary evaporation at 100-130 ℃ for 1-4 h, and removing tetrahydrofuran and unreacted micromolecular silane to obtain the alkoxy end-capped liquid fluorosilicone rubber.
Analyzing the product by Gel Permeation Chromatography (GPC) to obtain the number average molecular weight (M)n) Is 930.
The product was analyzed by infrared spectroscopy (FT-IR) test, and the infrared spectrum is shown in FIG. 1. Wherein: 1091cm-1(Si-O-C)，1000-1100cm-1(Si-O-Si)，2849cm-1(-OCH3)。
Examples 2 to 7
An alkoxy end-capped liquid fluorosilicone rubber is prepared by the following steps:
the procedure is as in example 1, the number average molecular weight (M) of the alpha, omega-hydroxy-terminated polymethyltrifluoropropylsiloxane addedn) The type of the hydroalkoxysilane varies depending on the kind, specific amount of the addition and number average molecular weight (M) of the productn) See table 2.
TABLE 2
Figure BDA0003029072220000081
The IR spectra of examples 2-7 were the same as in example 1.
Example 8
The dealcoholized room temperature vulcanized fluorosilicone sealant comprises the following components:
Figure BDA0003029072220000082
the preparation method of the dealcoholized room temperature vulcanized fluorosilicone sealant comprises the following steps:
putting the gas-phase white carbon black and the iron oxide red required by the experiment into an oven, and heating to 100 ℃ to dry for 3 hours; weighing trimethoxy end-capped liquid fluorosilicone rubber (M) according to a formulan13800, product of example 2), fumed silica, red iron oxide, trimethoxy-capped liquid fluorosilicone rubber (M)n930 for example 1), dibutyltin dilaurate, were placed in a planetary stirrer and premixed under vacuum for 10-15 min. And then putting the premixed sealant into a three-roll grinding machine for uniformly mixing to obtain the room-temperature dealcoholized vulcanized fluorosilicone sealant compound. And injecting the sealant sizing material into a mold, then strickling by using a scraper, and standing for 7 days under the conditions that the humidity is 50% and the temperature is 25 ℃ to obtain the vulcanized rubber of the fluorosilicone sealant.
The sealant compound was subjected to rheological property test analysis by an antopa rheometer (model: MCR-52), and the results are shown in fig. 2. It can be seen that in the state of humidity of 50% and temperature of 25 ℃, the viscosity of the rubber compound is rapidly increased within 60min after the rubber compound is mixed, which indicates that the rubber compound is rapidly vulcanized and crosslinked.
The thermogravimetric property of the vulcanizate was analyzed by a thermogravimetric analyzer (TGA) and the results are shown in fig. 3. It can be seen that the initial decomposition temperature (temperature at 5% mass loss) is 373 deg.C and the decomposition rate is the fastest at 513 deg.C, 1.6%/deg.C.
According to GB/T528-: tensile strength 1.6MPa, elongation at break 310%.
According to HG/T2413.2-1992, the Shore A hardness of the vulcanized rubber is tested, and the results are as follows: 12.
example 9
The dealcoholized room temperature vulcanized fluorosilicone sealant comprises the following components:
Figure BDA0003029072220000091
the preparation method of the dealcoholized room temperature vulcanized fluorosilicone sealant comprises the following steps:
the procedure is as in example 8, the trimethoxy end-capped liquid fluorosilicone rubber (M) of example 8 is preparedn13800, product of example 2) was replaced with α, ω -hydroxy-terminated polymethyltrifluoropropylsiloxane (M)n13500), the sealant compound was poured into the mold and subsequently smoothed with a spatula and left to stand at a humidity of 50% and a temperature of 25 ℃ for 7 days, the sealant compound still being in a fluid state and uncured and crosslinked.
The sealant compound was subjected to rheological property test analysis by an antopa rheometer (model: MCR-52), and the results are shown in fig. 2. It can be seen that in the state of humidity of 50% and temperature of 25 ℃, the viscosity of the rubber compound after the mixing is completed is not changed basically within 120min, which indicates that the vulcanization crosslinking reaction of the rubber compound is not performed basically.
Example 10
The dealcoholized room temperature vulcanized fluorosilicone sealant comprises the following components:
Figure BDA0003029072220000092
the preparation method of the dealcoholized room temperature vulcanized fluorosilicone sealant comprises the following steps:
the procedure is as in example 8, the trimethoxy end-capped liquid fluorosilicone rubber (M) of example 8 is preparedn930, product of example 1), the sealant compound was injected into the mold and then smoothed with a spatula and left to stand at a humidity of 50% and a temperature of 25 ℃ for 7 days with complete vulcanization of the sealant compound.
Performing rheology on the sealant rubber material by an Antopa rheometer (model: MCR-52)The results of the performance test analysis are shown in FIG. 2. It can be seen that in the state of humidity of 50% and temperature of 25 ℃, the viscosity of the rubber compound is slowly increased within 120min after the rubber compound is mixed, which indicates that the vulcanization crosslinking reaction of the rubber compound is slow. Example 10 shows a slower viscosity increase compared to example 8, indicating that Tetraethoxysilane (TEOS) does not perform as well as a cross-linking agent as trimethoxy terminated liquid fluorosilicone rubber (M)n930, example 1 product).
Example 11
The dealcoholized room temperature vulcanized fluorosilicone sealant comprises the following components:
Figure BDA0003029072220000101
the preparation method of the dealcoholized room temperature vulcanized fluorosilicone sealant comprises the following steps:
the procedure of example 8 was the same as that of example 8, the trimethoxy end-capped liquid fluorosilicone rubber (Mn 13800, product of example 2) of example 8 was replaced with trimethoxy end-capped liquid fluorosilicone rubber (Mn 9500, product of example 5), the sealant compound was poured into a mold, and then, the mold was scraped flat with a spatula, and the sealant was left to stand at a humidity of 50% and a temperature of 25 ℃ for 7 days, thereby obtaining a vulcanized rubber of fluorosilicone sealant.
The sealant compound was subjected to rheological property test analysis by an antopa rheometer (model: MCR-52), and the results are shown in fig. 2. It can be seen that in the state of humidity of 50% and temperature of 25 ℃, the viscosity of the rubber compound increases at a fast speed within 120min after the rubber compound is mixed, which indicates that the rubber compound vulcanization crosslinking reaction is relatively fast. Example 11 showed a slower viscosity increase than example 8. The viscosity increased faster in example 11 compared to example 9, indicating that the resulting trimethoxy end-capped liquid fluorosilicone rubber (Mn 9500, product of example 5) had better cure properties.
According to GB/T528-: tensile strength of 1.0MPa and breaking elongation of 200%.
According to HG/T2413.2-1992, the Shore A hardness of the vulcanized rubber is tested, and the results are as follows: 20.
example 12
The dealcoholized room temperature vulcanized fluorosilicone sealant comprises the following components:
Figure BDA0003029072220000102
the preparation method of the dealcoholized room temperature vulcanized fluorosilicone sealant comprises the following steps:
the procedure of example 8 was the same as that of example 8, except that dimethoxy terminated liquid fluorosilicone rubber (Mn 13800, product of example 2) in example 8 was replaced with dimethoxy terminated liquid fluorosilicone rubber (Mn 9450, product of example 7), and the sealant compound was poured into a mold, followed by leveling with a spatula and leaving at a humidity of 50% and a temperature of 25 ℃ for 7 days to obtain a vulcanized rubber of fluorosilicone sealant.
The sealant compound was subjected to rheological property test analysis by an antopa rheometer (model: MCR-52), and the results are shown in fig. 2. It can be seen that in the state of humidity of 50% and temperature of 25 ℃, the viscosity of the rubber compound is slowly increased within 120min after the rubber compound is mixed, which indicates that the vulcanization crosslinking reaction of the rubber compound is slow. Example 12 showed a slower viscosity increase than example 11, indicating that the cure rate of the dimethoxy terminated liquid fluorosilicone rubber (Mn 9450, product of example 7) was not as fast as that of the trimethoxy terminated liquid fluorosilicone rubber (Mn 9500, product of example 5).
Finally, it should be noted that: the above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.

Claims (18)

1. An alkoxy end-capped liquid fluorosilicone rubber is characterized in that: the structural formula is shown as formula 1:
Figure FDA0003516194840000011
wherein: n is an integer of 4 to 150, a is 0 or 1, R is C(1-12)Alkyl radical, R1Is C(1-5)An alkyl group, a carboxyl group,
R2is C(1-5)An alkyl group; the alkoxy end-capped liquid fluorosilicone rubber is used as a dealcoholization type room temperature vulcanization fluorosilicone sealant component.
2. The alkoxy-terminated liquid fluorosilicone rubber according to claim 1, wherein: n is 4, 54 and 78; r is methyl; r1Is methyl; r2Is methyl or ethyl.
3. An alkoxy-terminated liquid fluorosilicone rubber according to claim 2, wherein:
the compound of formula 1 is selected from Table 1
Compound numbering n a R R1 R2 1 4 0 Methyl radical Methyl radical Methyl radical 2 4 0 Methyl radical Methyl radical Ethyl radical 3 4 1 Methyl radical Methyl radical Methyl radical 4 4 1 Methyl radical Methyl radical Ethyl radical 5 54 0 Methyl radical Methyl radical Methyl radical 6 54 0 Methyl radical Methyl radical Ethyl radical 7 54 1 Methyl radical Methyl radical Methyl radical 8 54 1 Methyl radical Methyl radical Ethyl radical 9 78 0 Methyl radical Methyl radical Methyl radical 10 78 0 Methyl radical Methyl radical Ethyl radical 11 78 1 Methyl radical Methyl radical Methyl radical 12 78 1 Methyl radical Methyl radical Ethyl radical
。
4. The alkoxy-terminated liquid fluorosilicone rubber according to claim 1, wherein: the number average molecular weight (Mn) of the alkoxy end-capped liquid fluorosilicone rubber is 930-13900.
5. The alkoxy-terminated liquid fluorosilicone rubber according to claim 4, wherein: the number average molecular weight (Mn) of the alkoxy-terminated liquid fluorosilicone rubber is 930, 13700-13900 or 9450-9600.
6. An alkoxy-terminated liquid fluorosilicone rubber according to claim 5, wherein: the number average molecular weight (Mn) of the alkoxy-terminated liquid fluorosilicone rubber is 930 or 13800.
7. The method for preparing an alkoxy-terminated liquid fluorosilicone rubber according to claim 1, comprising the steps of:
Figure FDA0003516194840000021
wherein: n is an integer of 4 to 150, R is C(1-12)Alkyl, a is 0 or 1, R1Is C(1-5)Alkyl radical, R2Is C(1-5)An alkyl group.
8. The method for preparing an alkoxy-terminated liquid fluorosilicone rubber according to claim 1, comprising the steps of:
(1) end capping reaction:
under the protection of inert gas, uniformly mixing alpha, omega-hydroxyl-terminated polymethyl trifluoropropyl siloxane, a catalyst and a solvent, heating, injecting hydrogen-containing alkoxy silane into the system for dehydrogenation condensation reaction, and continuing heating and reflux reaction after injection;
(2) purification of the product
And after the reaction is completed, cooling to room temperature, filtering the mixed liquid to remove the supported catalyst, and performing rotary evaporation to remove the solvent and the micromolecules in the system to obtain the alkoxy-terminated liquid fluorosilicone rubber.
9. The method for preparing an alkoxy-terminated liquid fluorosilicone rubber as claimed in claim 8, wherein the catalyst in step (1) comprises a supported catalyst comprising a noble metal selected from platinum and palladium; the catalyst comprises a supported palladium carbon catalyst with palladium content of 3-6%.
10. The method for preparing an alkoxy-terminated liquid fluorosilicone rubber as claimed in claim 9, wherein said palladium content in step (1) is 5%.
11. The method for preparing an alkoxy-terminated liquid fluorosilicone rubber according to claim 8, wherein: in the step (1), the adding amount of the catalyst is 0.4-2% of the mass of the alpha, omega-hydroxyl-terminated polymethyl trifluoropropyl siloxane; the mass ratio of the solvent to the alpha, omega-hydroxyl-terminated polymethyl trifluoropropyl siloxane is (2-10): 1; the molar ratio of the hydrogen-containing alkoxy silane to the alpha, omega-hydroxyl-terminated polymethyl trifluoropropyl siloxane is (2-5): 1.
12. the method for preparing an alkoxy-terminated liquid fluorosilicone rubber according to claim 11, wherein: the mass ratio of the solvent to the alpha, omega-hydroxyl-terminated polymethyl trifluoropropyl siloxane is preferably (2-3): 1.
13. the method for preparing an alkoxy-terminated liquid fluorosilicone rubber according to claim 12, wherein: the molar ratio of the hydrogen-containing alkoxy silane to the alpha, omega-hydroxyl-terminated polymethyl trifluoropropyl siloxane is 3: 1.
14. the method for preparing an alkoxy-terminated liquid fluorosilicone rubber according to claim 8, wherein: the number average molecular weight (M) of the alpha, omega-terminal hydroxyl polymethyltrifluoropropylsiloxanen) 610, 9100 or 13500.
15. The method for preparing an alkoxy-terminated liquid fluorosilicone rubber according to claim 8, wherein: the hydrogen-containing alkoxy silane in the step (1) is trimethoxy hydrosilane, triethoxy hydrosilane or methyl dimethoxy hydrosilane.
16. The method for preparing an alkoxy-terminated liquid fluorosilicone rubber according to claim 8, wherein:
the reflux reaction time in the step (1) is 5-10 h;
heating to 50-70 ℃, and injecting and adding hydrogen-containing alkoxy silane into the system;
the rotary evaporation temperature in the step (2) is 100-130 ℃, and the time is 1-4 h.
17. A dealcoholized room temperature vulcanized fluorosilicone sealant is characterized by comprising 104 parts of the alkoxy end-capped liquid fluorosilicone rubber as claimed in any one of claims 1 to 6, 10 to 50 parts of fumed silica, 2 to 8 parts of iron oxide red and 0.2 to 1.5 parts of dibutyltin dilaurate.
18. The dealcoholization type room temperature vulcanization fluorosilicone sealant as claimed in claim 17, which comprises 104 parts of alkoxy end capping liquid fluorosilicone rubber, 10 parts of fumed silica, 3 parts of iron oxide red and 0.5 part of dibutyltin dilaurate.
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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6297302B1 (en) * 1999-08-17 2001-10-02 Xerox Corporation Stabilized fluorosilicone materials
CN1718665A (en) * 2005-06-21 2006-01-11 广州市白云化工实业有限公司 Organic silicon fluoro water proofing agent and its preparation method
CN103936995A (en) * 2013-05-20 2014-07-23 深圳市泰科科技有限公司 Preparation method of alkoxy-terminated linear polysiloxane

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6297302B1 (en) * 1999-08-17 2001-10-02 Xerox Corporation Stabilized fluorosilicone materials
CN1718665A (en) * 2005-06-21 2006-01-11 广州市白云化工实业有限公司 Organic silicon fluoro water proofing agent and its preparation method
CN103936995A (en) * 2013-05-20 2014-07-23 深圳市泰科科技有限公司 Preparation method of alkoxy-terminated linear polysiloxane

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