CN111909341A - Preparation method of polyurethane - Google Patents
Preparation method of polyurethane Download PDFInfo
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- CN111909341A CN111909341A CN201910383796.6A CN201910383796A CN111909341A CN 111909341 A CN111909341 A CN 111909341A CN 201910383796 A CN201910383796 A CN 201910383796A CN 111909341 A CN111909341 A CN 111909341A
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- polyurethane
- thioether
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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
- C08G18/00—Polymeric products of isocyanates or isothiocyanates
- C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
- C08G18/28—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the compounds used containing active hydrogen
- C08G18/40—High-molecular-weight compounds
- C08G18/52—Polythioethers
Abstract
The invention provides a preparation method of polyurethane, which comprises the following steps: taking sulfhydryl or hydroxyl terminated thioether prepolymer and isocyanate as raw materials, adding one or two of a catalyst or an initiator, and polymerizing at 50-90 ℃ in an inert gas atmosphere to obtain polyurethane; the thioether prepolymer only contains one type of repeating unit, the repeating unit contains thioether bonds, and the main chain of the thioether prepolymer is unbranched or connected with short-chain branches or phenyl. The invention adopts the thiol or hydroxyl terminated thioether prepolymer or adopts the thioether thiol prepolymer, polyether and polyester polyol as mixed raw materials to prepare the functional polyurethane, endows the polyurethane material with good bonding stability, low-temperature property and excellent flame retardant property, and has good industrial application prospect.
Description
Technical Field
The invention belongs to the technical field of preparation of high polymer materials, and particularly relates to a preparation method of polyurethane.
Background
Polyurethane (PU) has gained a great deal of development in recent years on a global scale as one of six important synthetic materials. Currently, western europe, north america, and asia-pacific region account for over 85% of the total global volume, with asia-pacific region already being the largest global polyurethane market, accounting for around 45% of the global market share.
With the rapid development of the Chinese building field, the automobile industry, the electronic equipment, the new energy and the environmental protection industry, the demand of polyurethane products is greatly pulled. At present, the industrial scale of polyurethane industry in China is about 1200 ten thousand, the industrial scale stably stays at the first position of the world, and products mainly comprise the fields of building heat-preservation polyurethane foam, automobile plastic, electronic equipment, clothing fiber, shoe plastic and the like.
The polyurethane material is widely applied to production and manufacturing of airplanes, high-speed rails and automobiles, on one hand, the rich material source of polyurethane, the flexibility of the formula and the convenience of forming processing are very easy to prepare parts such as seats, heat-insulating layers and the like in various shapes, and on the other hand, compared with other materials, the polyurethane material can effectively reduce the weight of the airplanes, the high-speed rails and the automobiles and improve the fuel economy efficiency.
According to the previous data, once an accident occurs to the airplane, particularly in the forced landing process, about 15-20% of casualties are caused by collision and falling injury, and 60-70% of casualties are caused by burning and death by smoke fire after the cabin fires; in more car accidents, due to the flammability of the seats and related materials in the car, a 30-60s car will ignite completely upon a fire in the event of an accident, leaving the time for the driver and passengers to escape very short. Therefore, the flame-retardant and low-fuming polyurethane has important application value and safety significance for related application fields.
The China has the largest building market in the world, more than 95% of buildings still have high energy consumption, the building energy consumption reaches 27% of the energy consumption of the whole society, and 50% of national energy consumption is consumed on buildings by 2020 without energy-saving measures. Building energy conservation is an important measure for realizing low-carbon green economy in China. At present, related departments such as the building department and the like have made building energy-saving implementation plans, and the plans of further saving energy by 65% in six cities such as Beijing, Tianjin, Dalian, Qingdao, Shanghai, Shenzhen and the like are forcibly pushed, 75% of energy is saved in the eastern region of the newly-built building in 2020, 65% of energy is saved in the Chinese and western regions, and energy-saving transformation is completed on most buildings. However, the biggest problems of the polyurethane heat-insulating materials are that the polyurethane materials are extremely easy to burn, flammable fatal defects are generated while heat-insulating and energy-saving are carried out, and after a great fire disaster of 11 and 15 in Shanghai, the country once suspends the action of a building energy-saving implementation plan, and provides higher flame-retardant specifications and requirements; the currently developed research for solving the flame retardance of polyurethane mainly carries out flame retardance by adding phosphorus-containing or other flame retardant additives, and the flame retardant has the defects of large addition amount (15-20%), serious smoke generation, more serious smoke poisoning in case of fire, flame retardance and reduction of physical properties of materials.
Therefore, the application needs to be satisfied by a cheap, massive and body-type flame-retardant polyurethane material.
Disclosure of Invention
In view of the above, the main object of the present invention is to provide a method for preparing polyurethane, which uses thiol or hydroxyl terminated thioether prepolymer or mixed raw materials of thioether thiol prepolymer, polyether and polyester polyol to prepare various functional polyurethanes, and endows the polyurethane material with good adhesion stability, low temperature characteristics and excellent flame retardant characteristics, and has good industrial application prospects.
The invention provides a preparation method of polyurethane, which comprises the following steps: taking sulfhydryl or hydroxyl terminated thioether prepolymer and isocyanate as raw materials, adding one or two of a catalyst or an initiator, and polymerizing at 50-90 ℃ in an inert gas atmosphere to obtain polyurethane; the thioether prepolymer only contains one type of repeating unit, the repeating unit contains thioether bonds, and the main chain of the thioether prepolymer is unbranched or connected with short-chain branches or phenyl.
Preferably, in the above method, the thiol-terminated thioether prepolymer structure comprises:
the hydroxyl terminated thioether prepolymer structure comprises:
wherein, R is alkyl, cycloalkyl, alkenyl or aryl, and m is 0-200.
Preferably, in the raw materials adopted in the above method, the isocyanate comprises one or both of diisocyanate or polyisocyanate. The diisocyanate structure is: OCN-R1-NCO, wherein R1 is alkyl or aryl. The polyisocyanate is one or two of carbodiimide modified isocyanate or uretonimine modified isocyanate.
More preferably, in several embodiments of the present invention, a preferred selection of diisocyanate is listed, and the diisocyanate may be toluene-2, 4-diisocyanate, 1, 6-hexamethylene diisocyanate or diphenylmethane diisocyanate. The reaction raw materials of the present invention are not limited to the ones exemplified in the examples based on the similar reaction principle.
More preferably, the carbodiimide-modified isocyanate is a carbodiimide group-containing compound produced by polycondensation of isocyanate itself in the presence of a catalyst and under heating. The polyisocyanate containing the carbodiimide structure can be further subjected to addition cyclization with isocyanate to generate the uretonimine modified isocyanate. In several examples of the invention, the preferred values for the content of functional groups in the polyurethane prepared from the two modified isocyanates used in the preparation of the process are given: in the polyurethane prepared by taking the carbodiimide modified isocyanate as the raw material, the content of carbodiimide functional groups is 0.5-l0 percent; the content of the uretonimine functional group in the polyurethane prepared by using the uretonimine modified isocyanate as a raw material is 0.5-l 0%.
More preferably, in the above process, the polyurethane structure prepared on the basis of the aforementioned selected raw materials comprises:
the involved reaction formula is:
wherein R is alkyl, cycloalkyl, alkenyl or aryl;
r1 is alkyl or aryl;
m＝0-300，n＝5-50。
further preferably, in the above polyurethane structure, the structure of the thiol prepolymer can be designed to be unique according to the requirement of polyurethane, and is suitable for various applications, for example, benzene ring thiol is designed to improve the heat resistance and rigidity of the material, and olefin groups can be introduced to enable the polymer to further react. Specifically, in the structure of the polyurethane and thioether prepolymer, R may preferably be:
-CxH2x-，-CxH2x-2-or-CxH2x-1R6-；
Wherein R3 is-H, alkyl, alkoxy, halogen, amino or nitro;
r4 is-H, alkyl or alkoxy;
r5 is-H, alkyl, alkoxy or phenyl;
r6 is-H, -CH3、-C2H5、-C3H7or-Ph;
x＝1-18。
more preferably, the present invention further provides several preferred methods of obtaining the thiol-or hydroxy-terminated thioether prepolymer starting material in the above process, comprising:
the thioether prepolymer is prepared by taking small-molecular alkyne, diene or eneyne and one of hydrogen sulfide and binary or polythiol as raw materials, adding an initiator or a catalyst, and polymerizing at the high pressure of 1-11Mpa and the temperature of 10-320 ℃.
Specifically, the polymerization process under the high pressure of 1-11MPa and the temperature of 10-320 ℃ is preferably as follows: under the condition of adding a photoinitiator, reacting at the temperature of 20-30 ℃ and under the pressure of 1-3 Mpa and ultraviolet initiation; or reacting under the condition of adding a catalyst and under the pressure of 1-3 MPa and at the temperature of 45-55 ℃. When the raw materials are acetylene and small molecular derivatives thereof or diolefin and hydrogen sulfide, the supercritical CO can be used2Reacting under the pressure of 8-11 Mpa and the temperature of 20-30 ℃.
Or the thioether prepolymer is prepared by taking one of dihalogenated hydrocarbon or trihalohydrocarbon and hydrogen sulfide as raw materials, taking triethanolamine and diethylene glycol as solvents, adding a phase transfer catalyst, and polymerizing at high pressure at 0-200 ℃ and 0.1-0.5 MPa.
Specifically, the high-pressure polymerization process at 0-200 ℃ and 0.1-0.5MPa is preferably as follows: stirring the reaction system under the pressure of 0.2-0.5MPa and the temperature of 0-35 ℃ for reaction for 2-3H, heating the reaction system to the temperature of 110-200 ℃ after the pressure of the reaction system is reduced to 0.1-0.15MPa, continuing stirring the reaction system under the pressure of 0.18-0.22MPa for reaction for 1-1.5H, reducing the pressure of the reaction system to 0.1-0.15MPa, stopping heating, and replacing residual H by adopting inert gas2S, dripping methanol at the temperature of 75-85 ℃ and the stirring speed of 80-120r/min, continuously stirring for 10-15min, and replacing for 1-2h by inert gas to finish the reaction.
In the two reactions, the transformation that the end capping group of the thioether prepolymer is sulfydryl or hydroxyl is realized by adjusting the proportion of halogenated hydrocarbon or alkyne, eneyne and hydrogen sulfide.
The above two methods for obtaining thiol-or hydroxyl-terminated thioether prepolymer are specifically described in several embodiments of the present invention, and the reaction materials and conditions of thioether prepolymer are not limited to those listed in the embodiments based on similar reaction principles.
More preferably, the polymerization process of the polyurethane of the present invention comprises: and (2) mixing the thiol-or hydroxyl-terminated thioether prepolymer, a catalyst and an initiator, heating to 50-60 ℃ under the atmosphere of inert gas, dropwise adding isocyanate, and stirring for 2-3 hours at a constant temperature after dropwise adding is finished within 30-60min to obtain the polyurethane.
Preferably, in the above polyurethane preparation method, the catalyst includes dibutyltin dilaurate or an organic amine.
Preferably, in the above polyurethane preparation method, the raw material further includes polyether polyol or polyester diol to obtain a conventional diol and thiol ether polyol hybrid polyurethane, involving the reaction formula:
the HO-R2-OH is polyether glycol or polyester glycol or polyether glycol.
More preferably, when the raw materials include both thioether prepolymer and di-or polyol, the polymerization process of the polyurethane includes: mixing the thiol-group or hydroxyl-terminated thioether prepolymer, polyether glycol or polyester glycol, a catalyst and an initiator, adding part of diisocyanate, stirring and reacting for 1-2h at 70-90 ℃, adding the rest diisocyanate or polyisocyanate, and continuously stirring for 0.5-1h to obtain the common diol and thioether polyol hybrid polyurethane.
The invention provides a thioether polymer prepared by the preparation method and a product obtained by blending or crosslinking the thioether polymer.
More preferably, the polyurethane obtained by the above method can be further processed or reacted to improve the product performance. For example, in one embodiment of the invention, the polyalkenyl sulfide polyurethane is further blended with BPO or AIBN to significantly improve the bonding properties. In another embodiment of the present invention, flame retardant foam soft bodies are prepared by further reacting a polyalkenyl thioether polyurethane with a polyol.
Compared with the prior art, the invention has the beneficial effects that:
(1) the invention takes the thiol-group or hydroxyl-terminated thioether prepolymer as a raw material, or takes the thioether-thiol prepolymer, polyether and polyester polyol as a mixed raw material, the thioether polymer has high regularity of a main chain and high sulfur content, and carbon-carbon double bonds, phenyl and other structures can be introduced into the main chain of the polymer through the adjustment of the thioether prepolymer, so that the polyurethane structure is more diversified, and the prepared multifunctional polyurethane endows the polyurethane material with good bonding stability, low-temperature property and excellent flame-retardant property.
(2) The thioether prepolymer adopted by the invention has the advantages of simple preparation process, convenient processing and wide raw material source, and the polyurethane preparation method provided by the invention has the advantages of simple reaction process, easy control and good industrial application prospect.
(3) The polyurethane obtained by the invention can be further reacted to improve the product performance, expand the application range and the application field and ensure that the reaction is more beneficial to industrial implementation.
Detailed Description
In order to facilitate understanding of the present invention, the present invention will be described in more detail with reference to the following examples, but the scope of the present invention is not limited to the following specific examples.
Unless otherwise defined, all terms of art used hereinafter have the same meaning as commonly understood by one of ordinary skill in the art. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of the present invention.
Unless otherwise specifically stated, various raw materials, reagents, instruments, equipment and the like used in the present invention are commercially available or can be prepared by existing methods.
Example 1
This example provides a thioether prepolymer prepared from 1, 4-dichloro-2-butene and H2S is taken as a raw material, triethanolamine and diethylene glycol are taken as mixed solvents to carry out polymerization reaction, and the related reaction formula is as follows:
the reaction process comprises the following steps:
1. all reagents are dried by anhydrous sodium sulfate for 24 hours and then used;
2. adding 25g (0.2mol) of 1, 4-dichloro-2-butene into a 1L high-pressure kettle, adding 68g (0.4mol) of triethanolamine and 200mL of diethylene glycol for dissolving, adding 0.5g of lauryl trimethyl ammonium bromide serving as a phase transfer catalyst, continuously stirring for 30min at normal temperature, and waiting for the system to be clear;
3. introducing dry H under pressure24.5L of S gas is about 0.2mol, and the system pressure is increased to 0.3 MPa;
4. continuously stirring the high-pressure kettle at normal temperature for 2-3h, and starting heating after the system pressure is reduced to about 0.1 MPa; heating to 120 ℃ for about half an hour, increasing the system pressure to about 0.2MPa, and continuing the reaction for 1 hour; the pressure drop of the system is about 0.12 MPa.
5. Stopping heating while introducing N2Replacing residual hydrogen sulfide gas, introducing the exhaust gas into NaOH aqueous solution to absorb H2And S. The temperature of the system is reduced to about 80 ℃, the stirring speed is increased to 100 r/min, 200mL of methanol is dripped from a feeding port, and the stirring is continued for 10-15min after the methanol is added. General formula (N)2After the gas replacement for 1-2h, the reaction is ended.
6. Opening a lower valve of the high-pressure reaction kettle, discharging reaction liquid from the lower valve during continuous stirring, and filtering by a Buchner funnel to obtain prepolymer powder; soaking and cleaning for 2 times by respectively adopting water and methanol, and filtering to obtain 2-alkenyl butyl sulfide prepolymer powder. After filtration and drying, 16.2g of a prepolymer powder was obtained, representing a molar yield of 94.2%.
In a similar reaction, we adjusted 1, 4-dichloro-2-butene and H2The proportion of S raw materials is that under the same high-pressure polymerization reaction condition, prepolymer and high molecular prepolymer which are terminated by sulfhydryl, hydroxyl and halogen are respectively prepared by simple post-treatment, and the related reaction formula is as follows:
when the molar ratio of hydrogen sulfide to 1, 4-dichloro-2-butene is greater than 1:1, a mercapto-terminated thioether prepolymer is obtained. When the molar ratio of hydrogen sulfide to 1, 4-dichloro-2-butene is less than 1:1, a halogen-terminated thioether prepolymer is obtained, which further yields a hydroxyl-terminated thioether prepolymer under basic conditions.
When 1, 4-dichloro-2-butene and hydrogen sulfide are mixed in equal amount, thioether prepolymer with n being 5-300 is obtained, and the thioether prepolymer is suitable for use as functional monomer and special prepolymer.
Example 2
This example provides a thioether prepolymer prepared using dibromoethane and H2S is taken as a raw material, triethanolamine and diethylene glycol are taken as mixed solvents to carry out polymerization reaction, and the related reaction formula is as follows:
the reaction process comprises the following steps:
1. all reagents are dried by anhydrous sodium sulfate for 24 hours and then used;
2. adding 37.6g (0.2mol) of dibromoethane into a 1L high-pressure kettle, adding 68g (0.4mol) of triethanolamine and 200mL of diethylene glycol for dissolution, adding 0.5g of phase transfer catalyst lauryl trimethyl ammonium bromide, and continuously stirring for 30min at normal temperature until the system is clear;
3. introducing dry H under pressure24.5L of S gas is about 0.2mol, and the system pressure is increased to 0.3 MPa;
4. continuously stirring the high-pressure kettle at normal temperature for 2-3h, and starting heating after the system pressure is reduced to about 0.1 MPa; heating to 120 ℃ for about half an hour, increasing the system pressure to about 0.2MPa, and continuing the reaction for 1 hour; the pressure drop of the system is about 0.12 MPa.
5. Stopping heating while introducing N2Replacing residual hydrogen sulfide gas, introducing the exhaust gas into NaOH aqueous solution to absorb H2And S. The temperature of the system is reduced to about 80 ℃, the stirring speed is increased to 100 r/min, 200mL of methanol is dripped from a feeding port, and the stirring is continued for 10-15min after the methanol is added. General formula (N)2After the gas replacement for 1-2h, the reaction is ended.
6. Opening a lower valve of the high-pressure reaction kettle, discharging reaction liquid from the lower valve during continuous stirring, and filtering by a Buchner funnel to obtain polymer powder; soaking and cleaning for 2 times respectively by adopting water and methanol, filtering and drying to obtain 10.8g of polymer powder with the molar yield of 90 percent.
Similar reactions, we adjusted dibromoethane and H2The proportion of S raw materials is that under the same high-pressure polymerization reaction condition, prepolymer and high molecular polymer which are terminated by sulfhydryl, hydroxyl and halogen are respectively prepared by simple post-treatment, and the related reaction formula is as follows:
when the molar ratio of hydrogen sulfide to dibromoethane is greater than 1:1, a mercapto-terminated thioether prepolymer is obtained with n-0 to about 200. When the molar ratio of hydrogen sulfide to dibromoethane is less than 1:1, a halogen-terminated thioether prepolymer having n of about 0 to 200 is obtained, and a hydroxyl-terminated thioether prepolymer having n of about 1 to 200 is obtained under alkaline conditions.
When dibromoethane and hydrogen sulfide are mixed in equal amount, thioether polymer with n being 1-300 is obtained, and the thioether polymer is suitable for use as functional monomer and special polymer.
Example 3
This example provides a thioether prepolymer prepared by polymerizing acetylene and a thiol, which are used in the vinyl chloride industry, to produce a mercapto-terminated vinyl thioether macromonomer.
The reaction process comprises the following steps: adding 300mL of mixed solvent of acetone and water (acetone: water: 2:1) and Irgacure-11730.5 g of photoinitiator into a 1L high-pressure reaction kettle, introducing 52g of acetylene at 2MPa to about 2mol of acetylene, and enabling the air pressure to tend to be stable after acetone gas is absorbed and saturated; starting the slow introduction of H with stirring2And (3) introducing ultraviolet light into the reaction kettle from an observation hole through an optical fiber after the pressure of the S gas is increased to about 1MPa by about 2.1mol and 71.4g of S gas, starting a high-pressure mercury lamp beside the reactor for 10min, keeping the normal temperature and continuing the reaction for 1 hour, and finishing the reaction after the pressure is reduced to 0.1 MPa. Introduction of N2Displacing residual acetylene and hydrogen sulfide gas, and respectively introducing the exhaust gas into NaOH aqueous solution to absorb H2And S, introducing acetone to absorb acetylene, wherein the recovered hydrogen sulfide and acetylene gas can be recycled. General formula (N)2After the gas replacement for 1-2h, the reaction is ended. The high-pressure reaction kettle is opened to discharge the polymer viscous reaction liquid. To obtain mercapto-terminated polyethyl sulfur macromonomer with total weight of 416g, and evaporating acetone and ethanol to obtain about 120g of macromonomer, and the yield is 97%.
Example 4
This example, using 2, 4-diisocyanate (TDI), and a dihydroxy polythioether monomer, produces a polyurethane prepolymer involving the following reaction scheme:
174.15g/Mol
the reaction process comprises the following steps:
1. dehydrating the dihydroxy polythioether monomer for 24 hours by using a molecular sieve for later use;
2. testing the hydroxyl value of the dihydroxy polythioether monomer, and the hydroxyl value is 0.51 eq/Kg;
3. 500g of dihydroxy polythioether monomer was charged into a 1000mL three-necked flask, 5g of dibutyltin dilaurate was added, mechanical stirring was performed, and N was introduced2The temperature is raised to 55 ℃, 0.125mol (21.77g) of TDI (toluene diisocyanate) is slowly dripped into the flask, and the viscosity of the system is obviously increased after dripping is finished for 40 min. The temperature was kept for 2h to obtain a viscous liquid which was poured out while hot to obtain about 506g of polymer with a yield of 97.0%.
4. The polymer is hot-pressed to grow the following width and thickness respectively: 125mm by 13.0mm by 3.0mm sample strip, tested using the UL94-V fire retardant test: the flame retardant property reaches V0 level, the oxygen index is 31 percent, and the dripping phenomenon does not occur.
Example 5
The preparation of polyurethane prepolymers from diphenylmethane diisocyanate (MDI) and dimercaptopolythioether monomers involves the reaction formula:
250.25g/Mol
the reaction process comprises the following steps:
1. dehydrating the dimercaptopolythioether monomer by using a molecular sieve for 24 hours for later use;
2. testing the hydroxyl value of the dimercaptopolythioether monomer, wherein the hydroxyl value is 0.18 eq/Kg;
3. 500g of viscous dimercaptopolythioether liquid is taken and added into a 1000mL three-neck flask, 5g of dibutyltin dilaurate is added, mechanical stirring is adopted, and N is introduced2And the temperature is raised to 60 ℃, 0.045mol (11.26g) of MDI (diphenylmethane diisocyanate) is dissolved in 50mL of toluene, the toluene MDI solution is slowly dripped into the flask, and the viscosity of the system is obviously increased after the dripping is finished for 30 min. The incubation was continued for 2.5h to give a viscous liquid which was poured off hot to give 496g of polymer in 97.0% yield.
4. The polymer is hot-pressed to grow the following width and thickness respectively: 125mm by 13.0mm by 3.0mm sample strip, tested using the UL94-V fire retardant test: the flame retardant performance reaches V0 level, the oxygen index is 33 percent, and the dripping phenomenon is avoided.
Example 6
This example, using 2, 4-diisocyanate (TDI) and a dihydroxypolyalkenyl sulfide monomer to prepare a polyurethane prepolymer, involves the following reaction scheme:
174.15g/Mol
the reaction process comprises the following steps:
1. dehydrating the dihydroxy polyalkenyl sulfide monomer for 24 hours by adopting a molecular sieve for later use;
2. testing the hydroxyl value of the dihydroxyl polyalkenyl sulfide monomer, wherein the hydroxyl value is 0.6 eq/Kg;
3. 500g of dihydroxypolyalkenyl sulfide liquid is taken and added into a 1000mL three-neck flask, 5g of dibutyltin dilaurate is added, mechanical stirring is adopted, and N is introduced2And the temperature is raised to 50 ℃, 0.3mol (52.25g) of TDI (toluene diisocyanate) is taken, the TDI is slowly dripped into the flask, and the viscosity of the system is obviously increased after the dripping is finished for 50 min. The incubation was continued for 2h to give a viscous liquid which was poured off hot to give 496g of polymer in 97.0% yield.
4. The polymer is hot-pressed to grow the following width and thickness respectively: 125mm by 13.0mm by 3.0mm sample strip, tested using the UL94-V fire retardant test: the flame retardant performance reaches V0 level, the oxygen index is 29 percent, and the dripping phenomenon is avoided.
5. Bonding an aluminum plate sample with the polyalkenyl sulfide polyurethane, heating the aluminum plate to 80 ℃ after gluing, cooling, and then tightly bonding, wherein after 24 hours of stabilization, the shear bonding strength reaches 80 MPa;
6. BPO or AIBN with 0.5-2% is mixed with the polyalkenyl thioether polyurethane and then used for bonding an aluminum plate sample, the aluminum plate is heated to 80 ℃ after being glued and cooled, extremely tight bonding can be realized, and after 24 hours of stabilization, the shear bonding strength of the bonded aluminum plate reaches 280 MPa.
Example 7
This example, using 2, 4-diisocyanate (TDI) and a mercaptopolyalkenyl sulfide monomer to prepare a polyurethane prepolymer, involves the following reaction scheme:
the reaction process comprises the following steps:
1. dehydrating the dimercapto polyalkenyl sulfide monomer for 24 hours by adopting a molecular sieve for later use;
2. testing the hydroxyl value of the dimercaptopolyalkenyl sulfide monomer, wherein the hydroxyl value is 0.3 eq/Kg;
3. 500g of dimercaptopolyalkenyl sulfide liquid is taken and added into a 1000mL three-neck flask, 5g of dibutyltin dilaurate is added, mechanical stirring is adopted, and N is introduced2And raising the temperature to 58 ℃, taking 0.15mol (26.13g) of TDI (toluene diisocyanate), slowly dripping the TDI into the flask, and finishing dripping for 45min without obviously increasing the viscosity of the system. The temperature was kept for 3h, the mixture was stirred continuously to obtain a homogeneous mixture, which was poured out while hot to obtain 516g of polymer in 98.0% yield.
4. Sample strips of 125mm x 13.0mm x 3.0mm are prepared by using a polytetrafluoroethylene template, and are tested by using a UL 94-V-grade fireproof flame-retardant test: the flame retardant performance reaches V0 level, the oxygen index is 30 percent, and the dripping phenomenon is avoided.
Example 8
This example uses diphenylmethane diisocyanate (MDI) and a mercaptopolyalkenyl sulfide monomer to prepare a polyurethane prepolymer, involving the following reaction scheme:
the reaction process comprises the following steps:
1. dehydrating the dimercapto polyalkenyl sulfide monomer for 24 hours by adopting a molecular sieve for later use;
2. testing the hydroxyl value of the dimercaptopolyalkenyl sulfide monomer, wherein the hydroxyl value is 0.3 eq/Kg;
3. 500g of dimercaptopolyalkenyl sulfide liquid is taken, and addedPut into a 1000mL three-necked flask, 5g of dibutyltin dilaurate was added, and N was introduced thereto by mechanical stirring2And heating to 55 ℃, dissolving 0.15mol (37.5g) of MDI (diphenylmethane diisocyanate) in 50mL of toluene, slowly dripping the toluene MDI solution into the flask, and finishing dripping within 30-60min without obviously increasing the system viscosity. The temperature is kept for 2 to 3 hours, the mixture is stirred continuously to obtain a liquid which is mixed evenly, and the liquid is poured out when the liquid is hot, so that 521g of polymer is obtained, and the yield is 97.0 percent.
4. Sample strips of 125mm x 13.0mm x 3.0mm are prepared by using a polytetrafluoroethylene template, and are tested by using a UL 94-V-grade fireproof flame-retardant test: the flame retardant performance reaches V0 level, the oxygen index is 33 percent, and the dripping phenomenon is avoided.
Example 9
This example prepares a foamed thioether polyurethane, using thioether prepolymer, polyol and isocyanate, which are commonly used in polyurethane industry, as raw materials, and the involved reaction formula is:
the isocyanate used in this example includes diphenylmethane diisocyanate. The diphenylmethane diisocyanate used contains 0-6% by mass of 2,2 ' -diphenylmethane diisocyanate, 45.0-63.5% by mass of 4,4 ' -diphenylmethane diisocyanate, and 10-25.5% by mass of 2,4 ' -diphenylmethane diisocyanate.
The isocyanate adopted in this embodiment also includes the raw material of carbodiimide/uretonimine modified isocyanate, and the content of carbodiimide/uretonimine functional group in the finally prepared polyisocyanate terminated prepolymer is preferably 0.5-l0 wt%.
The polyol commonly used in the polyurethane industry in this example is a combination of polyol A and polyol B, wherein the polyol A contains an initiator with a functionality of 2-5, an oxyethylene group content of 60-100wt, an average molecular weight of 2000-10000, an equivalent weight of 450-5000, and a light value of 10-189 mgKOH/g;
the polyol B contains initiator with functionality of 2-5, oxyethylene content of 0-30wt, average molecular weight of 2000-10000, equivalent weight of 450-5000 and light value of 10-189 mgKOH/g.
The preparation process of the polyurethane comprises the following steps:
the preparation method comprises the following steps of stirring and reacting diphenylmethane diisocyanate and polyol in a reaction kettle at the material temperature of 80 ℃ for 1-2 hours, then adding toluene diisocyanate, tricyclic isocyanate and more than tricyclic isocyanate, optionally adding carbodiimide/uretonimine modified isocyanate, and stirring and mixing for 0.5-1 hour to obtain the polyisocyanate terminated prepolymer.
Further, the product is used for preparing a flame-retardant foam of a polyisocyanate-terminated prepolymer, wherein the foam is prepared from the following raw materials:
30 to 75 parts by weight of a polyisocyanate-terminated prepolymer;
100 parts by weight of a polyol C, an ethylene oxide propylene oxide based polyether polyol having an average molecular weight of 4800 and a functionality of 3, wherein the EO/PO ratio is 15/85, and a lightness of 35 mgKOH/g;
1-3.0 parts by weight of a cross-linking agent;
2.0 to 15 parts by weight of a chemical blowing agent or a physical blowing agent;
1-2.0 parts by weight of a surfactant;
and 0.1 to 2.0 parts by weight of a catalyst.
Wherein, the cross-linking agent, the surfactant and the catalyst are conventional agents in the field, and the cross-linking agent comprises but is not limited to alcohol amine cross-linking agents, such as diethanolamine, triethanolamine, amine cross-linking agent Wannate 6200 and the like. The surfactant includes, but is not limited to, silicone based surfactants such as dimethicone. Such catalysts include, but are not limited to, amine catalysts such as triethylenediamine, metal-containing catalysts such as dibutyltin dilaurate, stannous octoate, and the like. The blowing agent is preferably water.
The foamed soft body can be prepared by a method conventional in the art, and the preparation process of the foamed soft body in the embodiment includes but is not limited to a molding process using cold curing, wherein the mold temperature is 40-80 ℃, preferably 50-60 ℃, the foam is cured for 2-10 minutes, and the foam is cured for 1 hour to 2 days at normal temperature after being demoulded to obtain the foamed soft body.
And the UL 94-V-grade fireproof flame-retardant test is adopted for testing: the flame retardant performance reaches V0 level, the oxygen index is 32%, the dripping phenomenon is avoided, the smoke is small when the flame retardant meets fire in the air, and the flame retardant self-extinguishes immediately after the flame retardant leaves a fire source.
The polyisocyanate terminated prepolymer prepared by the embodiment has TDI content of 3-30wt, meets MT standard, and therefore has better environmental protection property. Meanwhile, the foam obtained in the embodiment has good openness, ball resilience and mechanical properties, and excellent humidity and heat resistance and processing characteristics; the shrinkage of foam in the process and the cracking in the rolling process are avoided; the stability of the foam is ensured, and the foam is not easy to collapse, bubble, hemp skin and the like; the physical properties of the foam can not be influenced, and the quality of the foam is ensured.
The polyisocyanate-terminated prepolymer obtained in this example, and the flame-retardant polyurethane foam containing the polyisocyanate-terminated prepolymer, are particularly suitable for high resilience foams having a certain load-bearing capacity in automobiles and furniture.
While preferred embodiments of the present invention have been described, additional variations and modifications in those embodiments may occur to those skilled in the art once they learn of the basic inventive concepts. Therefore, it is intended that the appended claims be interpreted as including preferred embodiments and all such alterations and modifications as fall within the scope of the invention. It will be apparent to those skilled in the art that various changes and modifications may be made in the present invention without departing from the spirit and scope of the invention. Thus, if such modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include such modifications and variations.
Claims (10)
1. A preparation method of polyurethane comprises the following steps: taking sulfhydryl or hydroxyl terminated thioether prepolymer and isocyanate as raw materials, adding one or two of a catalyst or an initiator, and polymerizing at 50-90 ℃ in an inert gas atmosphere to obtain polyurethane;
the thioether prepolymer only contains one type of repeating unit, the repeating unit contains thioether bonds, and the main chain of the thioether prepolymer is unbranched or connected with short-chain branches or phenyl.
2. The process for producing polyurethane according to claim 1, wherein: the mercapto-terminated thioether prepolymer structure comprises:
the hydroxyl terminated thioether prepolymer structure comprises:
wherein, R is alkyl, cycloalkyl, alkenyl or aryl, and m is 0-200.
3. The process for producing polyurethane according to claim 1, wherein: the isocyanate comprises one or two of diisocyanate or polyisocyanate; the diisocyanate structure is: OCN-R1-NCO, wherein R1 is alkyl or aryl; the polyisocyanate is one or two of carbodiimide modified isocyanate or uretonimine modified isocyanate.
4. A method of producing a polyurethane as claimed in claim 3, characterized in that: in the polyurethane prepared by taking the carbodiimide modified isocyanate as the raw material, the content of carbodiimide functional groups is 0.5-l0 percent; the content of the uretonimine functional group in the polyurethane prepared by using the uretonimine modified isocyanate as a raw material is 0.5-l 0%.
5. A process for the preparation of polyurethanes as claimed in claim 2 or 3, characterized in that: the polyurethane structure includes:
wherein R is alkyl, cycloalkyl, alkenyl or aryl; r1 is alkyl or aryl;
m＝0-300，n＝5-50。
6. the process for producing polyurethane according to claim 5, wherein: the R is:
Wherein R3 is-H, alkyl, alkoxy, halogen, amino or nitro;
r4 is-H, alkyl or alkoxy;
r5 is-H, alkyl, alkoxy or phenyl;
r6 is-H, -CH3、-C2H5、-C3H7or-Ph;
x＝1-18。
7. the process for producing polyurethane according to claim 2, wherein: the thioether prepolymer is prepared by taking small-molecular alkyne, diene or eneyne and one of hydrogen sulfide and binary or polythiol as raw materials, adding an initiator or a catalyst, and polymerizing under the high pressure of 1-11Mpa and at the temperature of 10-320 ℃;
or the thioether prepolymer is obtained by taking one of dihalogenated hydrocarbon or trihalohydrocarbon and hydrogen sulfide as raw materials, taking triethanolamine and diethylene glycol as solvents, adding a phase transfer catalyst, and carrying out high-pressure polymerization at 0-200 ℃ and 0.1-0.5 MPa;
the polymerization process of the polyurethane comprises the following steps: and (2) mixing the thiol-or hydroxyl-terminated thioether prepolymer, a catalyst and an initiator, heating to 50-60 ℃ under the atmosphere of inert gas, dropwise adding isocyanate, and stirring for 2-3 hours at a constant temperature after dropwise adding is finished within 30-60min to obtain the polyurethane.
8. A process for the preparation of thioether polymers according to any of claims 1-3, characterized in that: the catalyst comprises dibutyl tin dilaurate or an organic amine; the raw material also comprises polyether polyol or polyester diol.
9. The process for preparing a thioether polymer according to claim 8, wherein: the polymerization process of the polyurethane comprises the following steps: mixing the sulfhydryl or hydroxyl terminated thioether prepolymer, polyether glycol or polyester glycol, a catalyst and an initiator, adding diisocyanate, stirring and reacting at 70-90 ℃ for 1-2h, adding diisocyanate or polyisocyanate, and continuously stirring for 0.5-1h to obtain the polyurethane.
10. Thioether polymer prepared by the preparation method of any one of claims 1-9, and a product obtained by blending or crosslinking the thioether polymer.
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