Silicon-containing polycarbonate diol, polyurethane elastomer material and preparation method thereof

Abstract

The invention relates to a silicon-containing polycarbonate diol, a polyurethane elastomer material and a preparation method thereof, and belongs to the technical field of organic materials. The glass transition temperature (Tg) of the silicon-containing polycarbonate diol ranges from 40 DEG C to 60 DEG C below zero, the hydroxyl value ranges from 60.4 mgKOH / g to 67.9 mgKOH / g, the product purity is high, the product purity is 98 or above, and the number-average molecular weight of the polycarbonate diol ranges from 1900 Da to 2200 Da. The low-temperature flexibility of the polycarbonate diol is effectively improved, and the use temperature range of the polycarbonate diol is widened. The polycarbonate diol disclosed by the invention is stable in hydroxyl value and narrow in molecular weight distribution; the product quality is good, and subsequent application is facilitated. The polycarbonate diol is short in preparation time, high in efficiency, simple in technological process, mild in technological condition and suitable for large-scale industrial production. The raw materials are low in cost.

Description

Technical Field

[0001] The invention relates to a silicon-containing polycarbonate diol, a polyurethane elastomer material and a preparation method thereof, and belongs to the technical field of organic materials. Background Art

[0002] Polycarbonate diol (PCDL) is a new type of polyvalent compound with multiple carbonate-based repeating units on the main chain and hydroxyl groups at both ends of the main chain. Polycarbonate diol has the advantages of both polyether polyols and polyester polyols. As the soft segment of polyurethane materials, it has excellent mechanical properties, water resistance, friction resistance, thermal stability, solvent resistance and weather resistance. Polycarbonate diol is widely used in synthetic water-based polyurethane emulsions, TPU elastomers, polyurethane coatings, adhesives, leather and other materials, and has great application prospects.

[0003] The synthesis and application of polycarbonate diols have become a hot topic in the field of polyurethane materials. The traditional production methods of polycarbonate diols include phosgene method, cyclic carbonate ring-opening polymerization method, copolymerization of carbon dioxide and epoxide, and transesterification method. Among them, the phosgene method is the most traditional method, but it has been eliminated because phosgene is highly toxic and is accompanied by a large amount of hydrogen chloride by-products. In the cyclic carbonate ring-opening polymerization method, the raw material cyclic carbonate is expensive, the variety is small, and the cost is high. The copolymerization method of carbon dioxide and epoxide can only synthesize polycarbonate diols with a single structure, while the raw materials of the transesterification method are easy to obtain, and the molecular structure of the product is easy to adjust, which is more suitable for production.

[0004] The route for preparing polycarbonate diols by the ester exchange method is based on the ester exchange reaction between small molecule carbonates and small molecule diols. The reaction is a reversible reaction and requires the removal of by-products or the promotion of the reaction by means of pressurization.

[0005] Thermoplastic polyurethane (TPU) elastomers have excellent tensile properties, resilience, wear resistance and aging resistance due to their unique block linear molecular structure and structural designability. They can be widely used in many fields such as footwear and clothing, medical care, electronic devices, wires and cables, and transportation.

[0006] However, there is no polycarbonate diol type polyurethane in the prior art which has a short preparation time and good low temperature flexibility.

[0007] CN 118290715 A discloses a method for preparing flame-retardant polycarbonate polyol, but the production time is relatively long.

[0008] CN116284721A discloses a silicon-modified polycarbonate polyol and a preparation method thereof. The preparation method uses trimethyl silyl ester and glycerol as raw materials, performs an ester exchange reaction in the presence of a catalyst to produce an intermediate, and then performs an ester exchange and polycondensation reaction on the intermediate with a diol and a carbonate to generate a silicon-modified polycarbonate polyol; the prepared silicon-modified polycarbonate polyol has the following beneficial effects: the polycarbonate polyol product has a certain flame retardant effect through silicon modification, and due to the presence of side chain silicon elements, the viscosity of the polycarbonate polyol product is reduced, the crystallinity is improved, and the surface performance and touch of the downstream products are improved. It first synthesizes a silicon-modified polycarbonate polyol intermediate, and then synthesizes the intermediate into a silicon-modified polycarbonate polyol through a subsequent reaction, and the steps are complicated and not concise.

[0009] CN117986981A discloses a flame retardant and explosion-resistant polyurea elastomer material and a preparation method thereof, the method comprising the following steps: (1) mixing polyester polyol and terminal hydroxyalkyl polysiloxane and performing vacuum dehydration, then adding isocyanate, reacting under an inert atmosphere, and then filtering to obtain component A; (2) mixing amino-terminated polyether, amino-terminated polysiloxane, chain extender, phosphate polyol, liquid boron flame retardant and functional additive and performing vacuum dehydration to obtain component B; (3) placing component A and component B in a spraying device for spraying. The flame retardant and explosion-resistant polyurea elastomer material prepared by the method has high strength, good flexibility, can withstand high-strength and high-load explosion impact, and has flame retardant function. It can be used to improve the gas explosion resistance and TNT explosion impact resistance of buildings and equipment facilities in flammable and explosive places such as petrochemical enterprises, and can effectively reduce the explosion impact damage of petrochemical buildings.

[0010] CN102604066A discloses a method for preparing a polydimethylsiloxane-polycarbonate copolymer. Polydimethylsiloxane, diphenyl carbonate and magnesium chloride catalyst are added to a reaction vessel, inert gas protection, stirring, heating for melt transesterification reaction, and the product is cooled after the reaction is completed; then bisphenol A is added, inert gas protection, stirring, heating for polycondensation reaction; washing, filtering, drying, and obtaining a polydimethylsiloxane-polycarbonate copolymer. The polydimethylsiloxane-polycarbonate copolymer can be used for flame retardant PC or as a synergist for flame retardant PC; this transesterification method is safe and environmentally friendly because it does not use highly toxic phosgene. However, it has many steps and relatively cumbersome operations, which may lead to low production efficiency, and the condition control requirements for each step of the reaction are high, which increases the process difficulty and cost in the production process. And magnesium chloride is used as a catalyst, and after the reaction is completed, post-processing operations such as washing, filtering, and drying are required to remove the catalyst and other impurities to obtain a pure polydimethylsiloxane-polycarbonate copolymer.

[0011] CN110177822A discloses the synthesis of polycarbonate siloxane diol. Silicon-based polycarbonate, its preparation method and its use in copolymers, especially block copolymers for biomedical applications such as polyurethane synthesis. However, its reaction selectivity is low, the diversity of product structure increases, and it is difficult to accurately control the molecular structure and molecular weight distribution of PCDL. This will affect the performance stability and consistency of PCDL when it is subsequently used to synthesize materials such as polyurethane. And dihydroxybutyltetramethyldisiloxane has low hydroxyl reactivity than BDO, so its reaction rate is too slow.

[0012] CN114671994A discloses a silicone modified thermosetting polyester polyurethane elastomer material and its preparation method and application. The raw materials for preparing the silicone modified thermosetting polyester polyurethane elastomer material include polycarbonate diol, diisocyanate, terminal hydroxyl polydimethylsiloxane and a crosslinking agent. The present invention uses silicone resin as a modifier to improve the physical and chemical properties of the polyurethane elastomer material. In addition, the end group of the silicone resin used in the present invention carries an active group, which can undergo a copolymerization addition reaction with diisocyanate, thereby further improving the compatibility with the matrix; at the same time, by changing the addition ratio of the silicone resin, the mechanical strength and tribological properties of the material can also be adjusted. The results of the embodiments show that the silicone modified thermosetting polyester polyurethane elastomer material provided by the present invention has good mechanical properties, water lubrication friction properties, high temperature hydrolysis resistance and oil resistance.

[0013] CN115490827A discloses polycarbonate polydimethylsiloxane type polyurethane urea and its preparation method. The soft segment of the polyurethane copolymer includes a polydimethylsiloxane structure and a polycarbonate structure, wherein the polydimethylsiloxane structure is shown in formula (I), and the polycarbonate structure is shown in formula (II), wherein the definitions of the groups are as described in the specification, and the polyurethane has good biological stability and mechanical properties. CN118271561A discloses a polyurethane elastomer and its preparation method and application. The polyurethane elastomer of the present invention comprises a soft segment and a hard segment, and the soft segment and the hard segment are arranged alternately; wherein: the raw materials for synthesizing the soft segment at least include a polymer polyol, a polydimethylsiloxane diol and a polyisocyanate; and the hard segment includes a linear siloxane modified side chain. The present invention introduces the remaining structures of the polyisocyanate except the isocyanate group and the polar functional group carbamate into the soft segment, and at the same time uses the siloxane modified side chain in the hard segment to adjust the phase separation structure of the polyurethane, thereby providing a new functional polyurethane material. The composite material obtained by coating the substrate with the polyurethane significantly enhanced the tensile strength and tear strength of the material. The valve prepared by cutting the composite material into leaflets had excellent durability, indicating that the polyurethane can effectively extend the service life of the valve.

[0014] CN117986981A, CN114671994A, CN115490827A, and CN118271561A all add polydimethylsiloxane during the synthesis of polyurethane. In the reaction, polydimethylsiloxane and polyester polyol only simply physically mix and participate in the reaction, and their reaction is random, making it difficult to precisely control the position and distribution of polydimethylsiloxane in the polyurethane molecular chain. This will lead to non-uniform molecular structure, resulting in large performance differences in different parts of the material. During the reaction and molding process, excessive or irregular phase separation is likely to occur, and the formed phase region structure is not ideal. This irregular phase separation will cause a decline in the mechanical properties, thermal properties, etc. of the material. Summary of the Invention

[0015] The first object of the present invention is to provide a silicon-containing polycarbonate diol.

[0016] To achieve the first object of the present invention, the glass transition temperature (Tg) of the silicon-containing polycarbonate diol is -40°C to -60°C, the hydroxyl value is 60.4 to 67.9 mgKOH / g, the product purity is high, and its product purity is above 98. The number average molecular weight range of the polycarbonate diol is 1900 to 2200 Da, preferably 1950 to 2050 Da.

[0017] The structure of the silicon-containing polycarbonate diol is as follows: Formula I

[0018]

[0019] Wherein R is (CH 2 ) 4 or (CH 2 ) 6 When R is (CH 2 ) 4 3 < n 1 < 4, 1 < n 2 < 3, 1 < n 3 < 2, 2 < n < 3; when R is (CH 2 ) 6 4 < n 1 < 6, 1 < n 2 < 3, 1 < n 3 < 2, 2 < n < 3;

[0020] In a specific embodiment, the silicon-containing polycarbonate diol is prepared by the following method:

[0021] A. Under a protective atmosphere, a dihydroxy-terminated polydimethylsiloxane and a diol are uniformly mixed and then a catalyst is added, and after the temperature is raised to the reaction temperature of the transesterification, a carbonate is added dropwise for transesterification, and low-boiling point by-products generated during the reaction are removed by fractionation; the molecular weight of the dihydroxy-terminated polydimethylsiloxane is 100 to 300; the molar ratio of the total molar ratio of the carbonate: dihydroxy-terminated polydimethylsiloxane and the diol in step A is in the range of 1.0 to 1.4:1, preferably 1.25:1;

[0022] B. After the low-boiling point by-products are removed, the temperature is raised to 160-190°C and polycondensation is carried out under negative pressure.

[0023] The protective atmosphere in step A is an atmosphere that does not react with the reaction system, such as a nitrogen atmosphere.

[0024] In a specific embodiment, the reaction temperature of the transesterification in step A is 120°C to 170°C, preferably 150°C, the reaction time is 5 to 9 hours, preferably 7 hours, and the stirring speed is 40 to 80 r / min, preferably 50 r / min;

[0025] The temperature for fractionating the azeotrope of methanol and dimethyl carbonate is preferably 60 to 65°C, more preferably 63°C.

[0026] In a specific embodiment, the catalyst is a titanium catalyst; preferably at least one of isopropyl titanate, n-butyl titanate, isooctyl titanate, titanium acetylacetonate, titanium dioxide, potassium titanium oxalate, titanium tetrabenzoate, titanium tartrate, and titanium citrate, and more preferably n-butyl titanate;

[0027] The amount of the catalyst is preferably 0.005-0.01% by weight of the total feed weight, preferably 0.01%, and the total feed weight comprises dihydroxy-terminated polydimethylsiloxane, diol, and carbonate;

[0028] The carbonate is dimethyl carbonate, diethyl carbonate, ethylene carbonate, preferably dimethyl carbonate;

[0029] The diol is at least one of 1,4-butanediol, 1,6-hexanediol, 1,5-pentanediol, 1,4-cyclohexanedimethanol, diethylene glycol and neopentyl glycol.

[0030] In a specific embodiment, the dihydroxy-terminated polydimethylsiloxane in step A accounts for 15% to 30% of the mass of the diol; the molecular weight of the dihydroxy-terminated polydimethylsiloxane is preferably 200;

[0031] Preferably, the diverter device in step A adopts the distillation column packing as θ ring, and the effective packing height of the distillation column should be 2 / 3 of the distillation column.

[0032] In a specific embodiment, the negative pressure in step B is below 200 Pa; the time of the polycondensation reaction is preferably 3 hours; and the temperature in step B is preferably raised to 170°C.

[0033] The second object of the present invention is to provide a method for preparing the silicon-containing polycarbonate diol.

[0034] To achieve the second object of the present invention, the method comprises: A. in a protective atmosphere, uniformly mixing a dihydroxy-terminated polydimethylsiloxane and a diol, adding a catalyst, heating to a reaction temperature of transesterification, and then dropping a carbonate to carry out transesterification, and removing low-boiling point byproducts generated during the reaction by fractionation; the molecular weight of the dihydroxy-terminated polydimethylsiloxane is 100 to 300; the molar ratio of the total molar ratio of the carbonate: dihydroxy-terminated polydimethylsiloxane and the diol in step A is in the range of 1.0 to 1.4:1, preferably 1.25:1;

[0035] B. After the low-boiling point by-products are removed, the temperature is raised to 160-190°C and polycondensation is carried out under negative pressure.

[0036] In a specific embodiment, the reaction temperature of the transesterification in step A is 120°C to 170°C, preferably 150°C, the reaction time is 5 to 9 hours, preferably 7 hours, and the stirring speed is 40 to 80 r / min, preferably 50 r / min;

[0037] The temperature for fractionating the azeotrope of methanol and dimethyl carbonate is preferably 60-65°C, more preferably 63°C;

[0038] The catalyst is a titanium catalyst; preferably at least one of isopropyl titanate, n-butyl titanate, isooctyl titanate, titanium acetylacetonate, titanium dioxide, potassium titanium oxalate, titanium tetrabenzoate, titanium tartrate, and titanium citrate, and more preferably n-butyl titanate;

[0039] The amount of the catalyst is preferably 0.005-0.01% by weight of the total feed weight, preferably 0.01%, and the total feed weight comprises dihydroxy-terminated polydimethylsiloxane, diol, and carbonate;

[0040] The carbonate is dimethyl carbonate, diethyl carbonate, ethylene carbonate, preferably dimethyl carbonate;

[0041] The diol is at least one of 1,4-butanediol, 1,6-hexanediol, 1,5-pentanediol, 1,4-cyclohexanedimethanol, diethylene glycol, and neopentyl glycol;

[0042] The amount of the dihydroxy-terminated polydimethylsiloxane in step A accounts for 15% to 30% of the mass of the diol; the molecular weight of the dihydroxy-terminated polydimethylsiloxane is preferably 200;

[0043] Preferably, the diverter device in step A adopts the distillation column packing as θ ring, and the effective packing height of the distillation column should be 2 / 3 of the distillation column.

[0044] In a specific embodiment, the negative pressure in step B is below 200 Pa; the time of the polycondensation reaction is preferably 3 hours; and the temperature in step B is preferably raised to 170°C.

[0045] The third object of the present invention is to provide a polyurethane elastomer material.

[0046] To achieve the third object of the present invention, the raw material for preparing the polyurethane elastomer material includes the silicon-containing polycarbonate diol mentioned above or the silicon-containing polycarbonate diol prepared by the above method.

[0047] Beneficial effects:

[0048] 1. The present invention effectively improves the low-temperature flexibility of polycarbonate diol and broadens its use temperature range.

[0049] 2. The polycarbonate diol of the present invention has a stable hydroxyl value and a narrow molecular weight distribution; the product has good quality and is conducive to its subsequent application.

[0050] 3. The preparation time of the polycarbonate diol of the present invention is short, the efficiency is high, the process flow is simple, the process conditions are mild, and it is suitable for large-scale industrial production.

[0051] 4. The raw material cost of the present invention is low.

[0052] 5. The present invention first uses dihydroxy-terminated polydimethylsiloxane to modify PCDL, thereby improving the crystallization performance, showing a liquid state with lower viscosity, and is more convenient to use than traditional PCDL.

[0053] 6. The present invention first modifies PCDL with dihydroxyl-terminated polydimethylsiloxane, and then uses it to synthesize polyurethane. The dihydroxyl-terminated polydimethylsiloxane is evenly introduced into the PCDL structure, which can better control the degree and structure of polyurethane microphase separation, make the phase distribution of hard segments and soft segments more reasonable, and help improve the comprehensive performance of the material. In addition, the modified PCDL structure is relatively regular, and the synthesized polyurethane has relatively uniform and stable performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] Figure 1 This is the HNMR graph of the silicon-containing polycarbonate diol prepared in Example 1 of the present invention. DETAILED DESCRIPTION

[0055] To achieve the first object of the present invention, the glass transition temperature (Tg) of the silicon-containing polycarbonate diol is -40°C to -60°C, the hydroxyl value is 60.4 to 67.9 mgKOH / g, the product purity is high, and the product purity is above 98. The number average molecular weight range of the polycarbonate diol is 1900 to 2200 Da, preferably 1950 to 2050 Da.

[0056] The structure of the silicon-containing polycarbonate diol is as follows formula I:

[0057]

[0058] Wherein R is (CH 2 ) 4 or (CH 2 ) 6 , when R is (CH 2 ) 4 , 3 < n 1 < 4, 1 < n 2 < 3, 1 < n 3 < 2, 2 < n < 3; when R is (CH 2 ) 6 , 4 < n 1 < 6, 1 < n 2 < 3, 1 < n 3 < 2, 2 < n < 3;

[0059] In a specific embodiment, the silicon-containing polycarbonate diol is prepared by the following method:

[0060] A. Under a protective atmosphere, the dihydroxy-terminated polydimethylsiloxane and the diol are uniformly mixed and then a catalyst is added. After heating to the transesterification reaction temperature, the carbonate is added dropwise for transesterification, and the low-boiling by-products generated during the reaction are removed by fractional distillation; the molecular weight of the dihydroxy-terminated polydimethylsiloxane is 100 to 300; the molar ratio of the carbonate to the total molar ratio of the dihydroxy-terminated polydimethylsiloxane and the diol in step A ranges from 1.0 to 1.4:1, preferably 1.25:1;

[0061] B. After the low-boiling by-products are removed, the temperature is raised to 160 to 190°C, and then polycondensation is carried out under negative pressure.

[0062] The protective atmosphere in step A is an atmosphere that does not react with the reaction system, such as a nitrogen atmosphere.

[0063] In a specific embodiment, the transesterification reaction temperature in step A is 120°C to 170°C, preferably 150°C, the reaction time is 5 to 9 h, preferably 7 h, and the stirring speed is 40 to 80 r / min, preferably 50 r / min;

[0064] The temperature for fractionating the azeotrope of methanol and dimethyl carbonate is preferably 60 to 65°C, more preferably 63°C.

[0065] In a specific embodiment, the catalyst is a titanium catalyst; preferably at least one of isopropyl titanate, n-butyl titanate, isooctyl titanate, titanium acetylacetonate, titanium dioxide, potassium titanium oxalate, titanium tetrabenzoate, titanium tartrate, and titanium citrate, and more preferably n-butyl titanate;

[0066] The amount of the catalyst is preferably 0.005-0.01% by weight of the total feed weight, preferably 0.01%, and the total feed weight comprises dihydroxy-terminated polydimethylsiloxane, diol, and carbonate;

[0067] The carbonate is dimethyl carbonate, diethyl carbonate, ethylene carbonate, preferably dimethyl carbonate;

[0068] The diol is at least one of 1,4-butanediol, 1,6-hexanediol, 1,5-pentanediol, 1,4-cyclohexanedimethanol, diethylene glycol and neopentyl glycol.

[0069] In a specific embodiment, the dihydroxy-terminated polydimethylsiloxane in step A accounts for 15% to 30% of the mass of the diol; the molecular weight of the dihydroxy-terminated polydimethylsiloxane is preferably 200;

[0070] Preferably, the diverter device in step A adopts the distillation column packing as θ ring, and the effective packing height of the distillation column should be 2 / 3 of the distillation column.

[0071] In a specific embodiment, the negative pressure in step B is below 200 Pa; the time of the polycondensation reaction is preferably 3 hours; and the temperature in step B is preferably raised to 170°C.

[0072] To achieve the second object of the present invention, the method comprises: A. in a protective atmosphere, uniformly mixing a dihydroxy-terminated polydimethylsiloxane and a diol, adding a catalyst, heating to a reaction temperature of transesterification, and then dropping a carbonate to carry out transesterification, and removing low-boiling point byproducts generated during the reaction by fractionation; the molecular weight of the dihydroxy-terminated polydimethylsiloxane is 100 to 300; the molar ratio of the total molar ratio of the carbonate: dihydroxy-terminated polydimethylsiloxane and the diol in step A is in the range of 1.0 to 1.4:1, preferably 1.25:1;

[0073] B. After the low-boiling point by-products are removed, the temperature is raised to 160-190°C and polycondensation is carried out under negative pressure.

[0074] In a specific embodiment, the reaction temperature of the transesterification in step A is 120°C to 170°C, preferably 150°C, the reaction time is 5 to 9 hours, preferably 7 hours, and the stirring speed is 40 to 80 r / min, preferably 50 r / min;

[0075] The temperature for fractionating the azeotrope of methanol and dimethyl carbonate is preferably 60-65°C, more preferably 63°C;

[0076] The catalyst is a titanium catalyst; preferably at least one of isopropyl titanate, n-butyl titanate, isooctyl titanate, titanium acetylacetonate, titanium dioxide, potassium titanium oxalate, titanium tetrabenzoate, titanium tartrate, and titanium citrate, and more preferably n-butyl titanate;

[0077] The amount of the catalyst is preferably 0.005-0.01% by weight of the total feed weight, preferably 0.01%, and the total feed weight comprises dihydroxy-terminated polydimethylsiloxane, diol, and carbonate;

[0078] The carbonate is dimethyl carbonate, diethyl carbonate, ethylene carbonate, preferably dimethyl carbonate;

[0079] The diol is at least one of 1,4-butanediol, 1,6-hexanediol, 1,5-pentanediol, 1,4-cyclohexanedimethanol, diethylene glycol, and neopentyl glycol;

[0080] The amount of the dihydroxy-terminated polydimethylsiloxane in step A accounts for 15% to 30% of the mass of the diol; the molecular weight of the dihydroxy-terminated polydimethylsiloxane is preferably 200;

[0081] Preferably, the diverter device in step A adopts the distillation column packing as θ ring, and the effective packing height of the distillation column should be 2 / 3 of the distillation column.

[0082] In a specific embodiment, the negative pressure in step B is below 200 Pa; the time of the polycondensation reaction is preferably 3 hours; and the temperature in step B is preferably raised to 170°C.

[0083] To achieve the third object of the present invention, the raw material for preparing the polyurethane elastomer material includes the silicon-containing polycarbonate diol mentioned above or the silicon-containing polycarbonate diol prepared by the above method.

[0084] The specific implementation modes of the present invention are further described below in conjunction with embodiments, but the present invention is not limited to the scope of the embodiments.

[0085] Example 1

[0086] Under nitrogen atmosphere, 150g 1,4-butanediol and 22.5g dihydroxy-terminated polydimethylsiloxane (the average molecular weight of dihydroxy-terminated polydimethylsiloxane in this experiment is about 200) were added to a 500mL four-necked flask, mixed evenly, and then 0.0361g n-butyl titanate was added. The four-necked flask was placed in an oil bath, and a fractionation device was placed on the flask mouth. After the temperature was raised to 150°C, 200. 0.08g dimethyl carbonate, the dropping time is 7h, the top temperature of the distillation tower is controlled at 63°C, and the atmospheric distillation reaction is carried out until no fraction flows out, and then the temperature is raised to 170°C, and the low-boiling point intermediate product is continuously evaporated by heat preservation. When no fraction flows out, the atmospheric distillation is completed; after changing to a pressure reducing device, start to evacuate to below 200Pa, and react in vacuum at a temperature of 170°C for 3h. After the reaction is completed, the silicon-containing polycarbonate diol is obtained.

[0087] The mass of the prepared polycarbonate diol product was 242.11 g, with a yield of 96%; the number average molecular weight was 1976, the hydroxyl value was 67.9 mgKOH / g, and the product purity was 98%. g ) is -40.6°C, and the viscosity is 1580 cP at 75°C.

[0088] The HNMR spectra of silicon-containing polycarbonate diol are shown in Figure 1 .

[0089] The silicon-containing polycarbonate diol described in Example 1 was added to a three-necked flask and dehydrated at 120°C under negative pressure for 1 hour, then cooled to 80°C under nitrogen atmosphere protection, and then N,N-dimethylformamide, isophorone diisocyanate and dibutyltin dilaurate were added for prepolymerization for 4 hours, and after the reaction, chain extension 1,4-butanediol was added and polycondensed for 1 hour to prepare the flame-retardant polyurethane elastomer.

[0090] Example 2

[0091] In a nitrogen atmosphere, 150g of 1,4-butanediol and 45g of dihydroxy-terminated polydimethylsiloxane (molecular weight of this experiment is 200) are added to a 500mL four-necked flask, mixed evenly, and then 0.0408g of n-butyl titanate is added. The four-necked flask is placed in an oil bath, and a fractionation device is placed on the flask mouth. After the temperature is raised to 150°C, 212.73g of dimethyl carbonate is added dropwise to the four-necked flask. The dropping time is 7h. The top temperature of the distillation tower is controlled at 63°C, and atmospheric distillation reaction is carried out until no fraction flows out. Then the temperature is raised to 170°C, and the low-boiling intermediate product is continuously evaporated by heat preservation. When no fraction flows out, the atmospheric distillation is completed; after changing to a pressure reducing device, start to evacuate to below 200Pa, and react in vacuum at a temperature of 170°C for 3h. After the reaction is completed, silicon-containing polycarbonate diol is obtained.

[0092] The mass of the prepared polycarbonate diol product was 246.12 g, the yield was 96%, the number average molecular weight was 2011, the hydroxyl value was 65.8 mgKOH / g, the product purity was 98%, and the glass transition temperature (T g ) is -46.1°C, and the viscosity is 1210 cP at 75°C.

[0093] The silicon-containing polycarbonate diol described in Example 2 was added to a three-necked flask and dehydrated at 120°C under negative pressure for 1 hour, then cooled to 80°C under nitrogen atmosphere protection, and then N,N-dimethylformamide, isophorone diisocyanate and dibutyltin dilaurate were added for prepolymerization for 4 hours, and after the reaction, chain extension 1,4-butanediol was added and polycondensed for 1 hour to prepare the flame-retardant polyurethane elastomer.

[0094] Example 3

[0095] Under nitrogen atmosphere, 90.12g 1,4-butanediol, 118.17g 1,6-hexanediol and 31.24g dihydroxy-terminated polydimethylsiloxane (molecular weight of this experiment is 200) were added to a 500mL four-necked flask, mixed evenly and then 0.0466g n-butyl titanate was added. The four-necked flask was placed in an oil bath, and a fractionation device was placed on the flask mouth. After heating to 150°C, 242 g of ethanol was added dropwise to the four-necked flask. .79g dimethyl carbonate, the addition time is 7h, the top temperature of the distillation tower is controlled at 63℃, and the atmospheric distillation reaction is carried out until no fraction flows out, and then the temperature is raised to 170℃, and the low-boiling point intermediate products are continuously evaporated by heat preservation. When no fraction flows out, the atmospheric distillation is ended; after changing to a pressure reducing device, start to evacuate to below 200Pa, and react in vacuum at a temperature of 170℃ for 3h. After the reaction is completed, silicon-containing polycarbonate diol is obtained.

[0096] The mass of the prepared copolymerized polycarbonate diol product was 266.055 g, the yield was 96%, the number average molecular weight was 2003, the hydroxyl value was 65.3 mgKOH / g, the product purity was 98%, and the glass transition temperature (T g ) is -49.2°C, and the viscosity is 1370 cP at 75°C.

[0097] The silicon-containing polycarbonate diol described in Example 3 was added to a three-necked flask and dehydrated at 120°C under negative pressure for 1 hour, then cooled to 80°C under nitrogen atmosphere protection, and then N,N-dimethylformamide, isophorone diisocyanate and dibutyltin dilaurate were added for prepolymerization for 4 hours, and after the reaction, chain extension 1,4-butanediol was added and polycondensed for 1 hour to prepare the flame-retardant polyurethane elastomer.

[0098] Example 4

[0099] Under nitrogen atmosphere, 90.12g 1,4-butanediol, 118.17g 1,6-hexanediol, and 62.487g dihydroxy-terminated polydimethylsiloxane (molecular weight used in this experiment is 200) were added to a 500mL four-necked flask, mixed evenly, and then 0.0531g n-butyl titanate was added. The four-necked flask was placed in an oil bath, and a fractionating device was placed on the flask mouth. After heating to 150°C, 26 0.35g dimethyl carbonate, the addition time is 7h, the top temperature of the distillation tower is controlled at 63℃, and the atmospheric distillation reaction is carried out until no fraction flows out, and then the temperature is raised to 170℃, and the low-boiling point intermediate products are continuously evaporated by heat preservation. When no fraction flows out, the atmospheric distillation is completed; after changing to a pressure reducing device, start to evacuate to below 200Pa, and react in vacuum at a temperature of 170℃ for 3h. After the reaction is completed, silicon-containing polycarbonate diol is obtained.

[0100] The mass of the prepared silicon-containing polycarbonate diol product was 359.93 g, the yield was 96%, the number average molecular weight was 1973, the hydroxyl value was 60.4 mgKOH / g, the product purity was 98%, and the glass transition temperature (T g ) is -57.9°C, and the viscosity is 1080 cP at 75°C.

[0101] The silicon-containing polycarbonate diol described in Example 4 was added to a three-necked flask and dehydrated at 120°C under negative pressure for 1 hour, then cooled to 80°C under nitrogen atmosphere protection, and then N,N-dimethylformamide, isophorone diisocyanate and dibutyltin dilaurate were added for prepolymerization for 4 hours, and after the reaction, chain extension 1,4-butanediol was added and polycondensed for 1 hour to prepare the flame-retardant polyurethane elastomer.

[0102] Comparative Example 1

[0103] Under nitrogen atmosphere, add 150g 1,4-butanediol to a 500mL four-necked flask, mix well and add 0.0337g n-butyl titanate, put the four-necked flask into an oil bath, put a fractionating device on the flask mouth, heat to 150°C and start to drop 187.40g dimethyl carbonate into the four-necked flask. The dropping time is 7h. The top temperature of the distillation tower is controlled at 63°C. Perform atmospheric distillation reaction until no fraction flows out. Then start to heat to 170°C. By keeping warm, continuously evaporate the low-boiling intermediate product. When no fraction flows out, the atmospheric distillation ends. After changing to a pressure reducing device, start to evacuate to below 200Pa, and react in vacuum at 170°C for 3h. After the reaction ends, homopolymer polycarbonate diol is obtained.

[0104] The mass of the prepared polycarbonate diol product was 231.08 g, the yield was 96%, the number average molecular weight was 1996, the hydroxyl value was 62.9 mgKOH / g, the product purity was 99%, and the glass transition temperature (T g ) is -36.7°C, and the viscosity is 2420 cP at 75°C.

[0105] The silicon-containing polycarbonate diol described in Comparative Example 1 was added to a three-necked flask and dehydrated at 120° C. under negative pressure for 1 hour, then cooled to 80° C. under nitrogen atmosphere protection, and then N,N-dimethylformamide, isophorone diisocyanate and dibutyltin dilaurate were added for prepolymerization for 4 hours, and after the reaction, chain extension 1,4-butanediol was added and polycondensed for 1 hour to prepare the flame-retardant polyurethane elastomer.

[0106] Comparative Example 2

[0107] Under nitrogen atmosphere, 90.12g 1,4-butanediol and 118.17g 1,6-hexanediol were added to a 500mL four-necked flask, mixed evenly, and then 0.0433g n-butyl titanate was added. The four-necked flask was placed in an oil bath, and a fractionation device was placed on the flask mouth. After the temperature was raised to 150°C, 225.175g dimethyl carbonate was added dropwise to the four-necked flask for 7h. The top temperature of the distillation tower was controlled at 63°C, and atmospheric distillation was carried out until no fraction flowed out. Then, the temperature was raised to 170°C, and the low-boiling intermediate product was continuously evaporated by heat preservation. When no fraction flowed out, the atmospheric distillation was terminated. After the pressure reducing device was replaced, vacuum was evacuated to below 200Pa, and vacuum reaction was carried out at a temperature of 170°C for 3h. After the reaction was completed, a copolymerized polycarbonate diol was obtained.

[0108] The mass of the prepared copolymerized polycarbonate diol was 245.9 g, the yield was 96%, the number average molecular weight was 1925, the hydroxyl value was 67.9 mgKOH / g, the product purity was 98%, the glass transition temperature was -45.3°C, and the viscosity was 2160 cP at 75°C.

[0109] The polycarbonate diol described in Comparative Example 2 was added to a three-necked flask and dehydrated at 120°C under negative pressure for 1 hour, then cooled to 80°C under nitrogen atmosphere protection, and then N,N-dimethylformamide, isophorone diisocyanate and dibutyltin dilaurate were added for prepolymerization for 4 hours, and after the reaction, chain extension 1,4-butanediol was added and polycondensed for 1 hour to prepare the flame-retardant polyurethane elastomer.

[0110] Comparative Example 3

[0111] In a nitrogen atmosphere, 150g of 1,4-butanediol and 75g of dihydroxy-terminated polydimethylsiloxane (molecular weight of this experiment is 200) are added to a 500mL four-necked flask, mixed evenly, and then 0.0408g of n-butyl titanate is added. The four-necked flask is placed in an oil bath, and a fractionation device is placed on the flask mouth. After the temperature is raised to 150°C, 229.64g of dimethyl carbonate is added dropwise to the four-necked flask. The dropping time is 7h. The top temperature of the distillation tower is controlled at 63°C, and atmospheric distillation reaction is carried out until no fraction flows out. Then the temperature is raised to 170°C, and the low-boiling intermediate product is continuously evaporated by heat preservation. When no fraction flows out, the atmospheric distillation is completed; after changing to a pressure reducing device, start to evacuate to below 200Pa, and react in vacuum at a temperature of 170°C for 3h. After the reaction is completed, silicon-containing polycarbonate diol is obtained.

[0112] The mass of the prepared polycarbonate diol product was 253.79 g, the yield was 96%, the number average molecular weight was 2011, the hydroxyl value was 65.8 mgKOH / g, the product purity was 98%, and the glass transition temperature (T g ) is -49.6°C, and the viscosity is 800 cP at 75°C.

[0113] The silicon-containing polycarbonate diol described in Comparative Example 3 was added to a three-necked flask and dehydrated at 120° C. under negative pressure for 1 hour, then cooled to 80° C. under nitrogen atmosphere protection, and then N,N-dimethylformamide, isophorone diisocyanate and dibutyltin dilaurate were added for prepolymerization for 4 hours, and after the reaction, chain extension 1,4-butanediol was added and polycondensed for 1 hour to prepare the flame-retardant polyurethane elastomer.

[0114] Comparative Example 4

[0115] Under nitrogen atmosphere, 90.12g 1,4-butanediol, 118.17g 1,6-hexanediol, and 104.15g dihydroxy-terminated polydimethylsiloxane (the molecular weight used in this experiment is 200) were added to a 500mL four-necked flask, mixed evenly, and then 0.0531g of n-butyl titanate was added. The four-necked flask was placed in an oil bath, and a fractionating device was placed on the flask mouth. After heating to 150°C, 28 3.83g dimethyl carbonate, the dropping time is 7h, the top temperature of the distillation tower is controlled at 63℃, and the atmospheric distillation reaction is carried out until no fraction flows out, and then the temperature is raised to 170℃, and the low-boiling point intermediate product is continuously evaporated by heat preservation. When no fraction flows out, the atmospheric distillation is completed; after changing to a pressure reducing device, start to evacuate to below 200Pa, and react in vacuum at a temperature of 170℃ for 3h. After the reaction is completed, silicon-containing polycarbonate diol is obtained.

[0116] The mass of the prepared silicon-containing polycarbonate diol product was 391.73 g, the yield was 96%, the number average molecular weight was 1973, the hydroxyl value was 60.4 mgKOH / g, the product purity was 98%, and the glass transition temperature (T g ) is -59.1°C, and the viscosity is 560 cP at 75°C.

[0117] The silicon-containing polycarbonate diol described in Comparative Example 4 was added to a three-necked flask and dehydrated at 120° C. under negative pressure for 1 hour, then cooled to 80° C. under nitrogen atmosphere protection, and then N,N-dimethylformamide, isophorone diisocyanate and dibutyltin dilaurate were added for prepolymerization for 4 hours, and after the reaction, chain extension 1,4-butanediol was added and polycondensed for 1 hour to prepare the flame-retardant polyurethane elastomer.

[0118] Various properties of the polyurethane elastomers synthesized in the examples and comparative examples were tested.

[0119] Table 1 Performance data of polyurethane elastomers of examples and comparative examples

[0120]

Claims

1. Silicon-containing polycarbonate diol, characterized in that: The glass transition temperature (Tg) of the silicon-containing polycarbonate diol is -40°C to -60°C, the hydroxyl value is 60.4 to 67.9 mg KOH / g, the product has high purity, and its product purity is above 98. The number average molecular weight range of the polycarbonate diol is 1900 to 2200 Da, preferably 1950 to 2050 Da.

2. The silicon-containing polycarbonate diol according to claim 1, characterized in that: The structure of the silicon-containing polycarbonate diol is as follows in Formula I: R is (CH2)4 or (CH2)6. When R is (CH2)4, 3 < n1 < 4, 1 < n2 < 3, 1 < n3 < 2, 2 < n < 3; when R is (CH2)6, 4 < n1 < 6, 1 < n2 < 3, 1 < n3 < 2, 2 < n < 3; Preferably, the silicon-containing polycarbonate diol is prepared by the following method: A. Under a protective atmosphere, the dihydroxy-terminated polydimethylsiloxane and the diol are uniformly mixed and then a catalyst is added. After heating to the transesterification reaction temperature, the carbonate is added dropwise for transesterification, and the low-boiling by-products generated during the reaction are removed by fractional distillation; the molecular weight of the polydimethylsiloxane is 100 to 300; the molar ratio of the carbonate in Step A: the total of the dihydroxy-terminated polydimethylsiloxane and the diol is 1.0 to 1.4:1, preferably 1.25:1; B. After the low-boiling by-products are completely removed, the temperature is raised to 160 to 190°C, and then polycondensation is carried out under negative pressure.

3. The silicon-containing polycarbonate diol according to claim 2, characterized in that: The transesterification reaction temperature in Step A is 120°C to 170°C, preferably 150°C, the reaction time is 5 to 9 h, preferably 7 h, and the stirring speed is 40 to 80 r / min, preferably 50 r / min; The temperature for fractionating out the methanol and dimethyl carbonate azeotrope is preferably 60 to 65°C, more preferably 63°C.

4. The silicon-containing polycarbonate diol according to claim 2 or 3, characterized in that: The catalyst is a titanium-based catalyst; preferably at least one of isopropyl titanate, n-butyl titanate, isooctyl titanate, titanium acetylacetonate, titanium dioxide, potassium oxalate titanate, tetrabenzoic acid titanate, tartaric acid titanate, citric acid titanate, and more preferably n-butyl titanate; The dosage of the catalyst is preferably 0.005 to 0.01% of the total feed weight, preferably 0.01%, and the total feed includes dihydroxy-terminated polydimethylsiloxane, diol, and carbonate; The carbonate is dimethyl carbonate, diethyl carbonate, ethylene carbonate, preferably dimethyl carbonate; The diol is at least one of 1,4-butanediol, 1,6-hexanediol, 1,5-pentanediol, 1,4-cyclohexanedimethanol, diethylene glycol, neopentyl glycol.

5. The silicon-containing polycarbonate diol according to claim 2 or 3, characterized in that: The feed of the dihydroxy-terminated polydimethylsiloxane in Step A accounts for 15 to 30% of the mass of the diol; the molecular weight of the dihydroxy-terminated polydimethylsiloxane is preferably 200; Preferably, for the shunt device in Step A, the distillation column packing is Θ ring, and the effective packing height of the distillation column should be 2 / 3 of the distillation column.

6. The silicon-containing polycarbonate diol according to claim 2 or 3, characterized in that: The negative pressure in Step B is below 200 Pa; the polycondensation reaction time is preferably 3 h; in Step B, the temperature is preferably raised to 170°C.

7. The method for preparing the silicon-containing polycarbonate diol according to any one of claims 1 to 6, characterized in that: The method comprises: A. in a protective atmosphere, uniformly mixing a dihydroxyl-terminated polydimethylsiloxane and a diol, adding a catalyst, heating to a reaction temperature of transesterification, then dripping carbonate to carry out transesterification, and removing low-boiling point byproducts generated during the reaction by fractionation; the molecular weight of the dihydroxyl-terminated polydimethylsiloxane is 100 to 300; the total molar ratio of carbonate: dihydroxyl-terminated polydimethylsiloxane and diol in step A is 1.0 to 1.4:1, preferably 1.25:1; B. After the low-boiling point by-products are removed, the temperature is raised to 160-190°C and polycondensation is carried out under negative pressure.

8. The method for preparing silicon-containing polycarbonate diol according to claim 7, characterized in that: The reaction temperature of the transesterification in step A is 120°C to 170°C, preferably 150°C, the reaction time is 5 to 9 hours, preferably 7 hours, and the stirring speed is 40 to 80 r / min, preferably 50 r / min; The temperature for fractionating the azeotrope of methanol and dimethyl carbonate is preferably 60-65°C, more preferably 63°C; The catalyst is a titanium catalyst; preferably at least one of isopropyl titanate, n-butyl titanate, isooctyl titanate, titanium acetylacetonate, titanium dioxide, potassium titanium oxalate, titanium tetrabenzoate, titanium tartrate, and titanium citrate, and more preferably n-butyl titanate; The amount of the catalyst is preferably 0.005-0.01% by weight of the total feed weight, preferably 0.01%, and the total feed weight comprises dihydroxy-terminated polydimethylsiloxane, diol, and carbonate; The carbonate is dimethyl carbonate, diethyl carbonate, ethylene carbonate, preferably dimethyl carbonate; The diol is at least one of 1,4-butanediol, 1,6-hexanediol, 1,5-pentanediol, 1,4-cyclohexanedimethanol, diethylene glycol, and neopentyl glycol; The amount of the dihydroxy-terminated polydimethylsiloxane in step A accounts for 15-30% of the mass of the diol; the molecular weight of the dihydroxy-terminated polydimethylsiloxane is preferably 200; Preferably, the diverter device in step A adopts the distillation column packing as θ ring, and the effective packing height of the distillation column should be 2 / 3 of the distillation column.

9. The method for preparing silicon-containing polycarbonate diol according to claim 7, characterized in that: The negative pressure in step B is below 200 Pa; the time of the polycondensation reaction is preferably 3 hours; and the temperature in step B is preferably raised to 170°C.

10. Polyurethane elastomer material, characterized in that: The raw material for preparing the polyurethane elastomer material includes the silicon-containing polycarbonate diol described in any one of claims 1 to 6 or the silicon-containing polycarbonate diol prepared by the method described in any one of claims 7 to 9.

Images