Polyurethane composition, polyurethane elastomer and preparation method thereof

Abstract

The present invention provides a polyurethane composition, a polyurethane elastomer and a preparation method thereof, wherein the polyurethane composition comprises a combination of component A and component B; the component A comprises a prepolymer containing a crystalline structure; the component B comprises a chain extender containing a branched structure, and the chain extender containing a branched structure is obtained by reacting a branched diol with a first aliphatic diisocyanate. The present invention forms a specific multiphase structure in the prepared polyurethane elastomer by designing and compounding the component A containing a crystalline structure and the component B having a branched structure, thereby having both high strength and high toughness, obtaining excellent tensile strength, tear strength and elongation at break, and having excellent comprehensive performance.

Description

Technical Field

[0001] The invention belongs to the technical field of polymer materials, and in particular relates to a polyurethane composition, a polyurethane elastomer and a preparation method thereof. Background Art

[0002] Polyurethane elastomers have good toughness, impact resistance, wear resistance, elasticity and mechanical strength, and their raw materials are rich in variety. The material can be transformed from different hardnesses through formula adjustment. It has a wide adjustable range and can meet the performance requirements in different application scenarios. It is widely used in the automotive industry, machinery industry, chemical industry, medical industry, transportation, sporting goods, electronics industry, coal and other industries.

[0003] Polyurethane elastomers can be divided into TDI (toluene diisocyanate) type, MDI (diphenylmethane diisocyanate) type, PPDI (phenylene diisocyanate) type, HDI (hexamethylene diisocyanate) type, etc. according to the different isocyanates used. They can be divided into polyether type, polyester type, and polyether polyester composite type according to the different polyols used. Usually, people combine different isocyanates with different polyols to adjust the performance of polyurethane elastomers and obtain elastomer products with different modulus and hardness. For example, CN110982042A discloses a method for preparing a polyurethane elastomer with adjustable hardness, which is prepared from three components: component A is a mixture of polytetramethylene glycol and a catalyst, component B is a prepolymer obtained by reacting polytetramethylene glycol and diisocyanate, and its NCO group content is 22-24%, and component C is an alcohol chain extender or an oligomeric diamine chain extender with a water content of ≤0.03%; during the preparation process, component A and component C are premixed as a curing agent component, and then component B and the curing agent component are mixed, poured into a mold, opened, and vulcanized to obtain a polyurethane elastomer with a Shore hardness range of A60-D75. CN104031238A discloses a method for preparing a high-damping and high-toughness thermoplastic polyurethane elastomer, which comprises the following steps: (1) dehydrating a polyester polyol, a fluorine-containing polyether diol and a catalyst in a reaction kettle to obtain a mixed polyol; heating a mixture containing at least one aromatic diisocyanate and at least one aliphatic diisocyanate, and adding the mixture to the mixed polyol to obtain a fluorine-containing mixed polyurethane prepolymer through reaction; (2) heating a chain extender, mixing the mixture with the fluorine-containing mixed polyurethane prepolymer, and stirring the mixture to obtain a thermoplastic polyurethane elastomer; wherein the chain extender is selected from one or more of 1,4-butanediol, 1,3-propylene glycol, 1,4-cyclohexanol, neopentyl glycol and 1,6-hexanediol. CN113717341A discloses a method for preparing a polyurethane elastomer, comprising the following steps: mixing polytetrahydrofuran diol and diisocyanate for polymerization reaction to obtain a prepolymer; mixing the prepolymer and a diamine chain extender and curing to obtain a polyurethane elastomer having good strength, toughness, wear resistance and hydrolysis resistance. CN106674471A discloses a thermoplastic polyurethane elastomer, the raw materials for preparation include: 22-55wt% aromatic diisocyanate and / or alicyclic diisocyanate, 2-16wt% chain extender, 30-70wt% polyester polyol; in the preparation process, firstly heating and melting the diisocyanate, then adding the polyester polyol and optionally a catalyst, generating a stable prepolymer at 70-100°C, then mixing the chain extender with the prepolymer and ripening to obtain the thermoplastic polyurethane elastomer.

[0004] In recent years, with the further expansion of the application of polyurethane elastomers, people have put forward higher requirements for the performance of polyurethane, hoping to obtain higher strength. However, when technicians optimize the formula of polyurethane to obtain high strength and excellent mechanical properties, the increase in hardness is often accompanied by a loss of toughness, resulting in an imbalance in the performance of the material, which is not suitable for some special working conditions. Therefore, the field urgently needs to develop a polyurethane material with both excellent mechanical strength and excellent toughness. Summary of the invention

[0005] In view of the deficiencies in the prior art, the object of the present invention is to provide a polyurethane composition, a polyurethane elastomer and a preparation method thereof. The polyurethane composition forms a specific multiphase structure in the prepared polyurethane elastomer by designing and compounding a component A containing a crystalline structure and a component B having a branched structure, thereby having both high strength and high toughness and excellent comprehensive performance.

[0006] To achieve this object, the present invention adopts the following technical solutions:

[0007] In a first aspect, the present invention provides a polyurethane composition, comprising a combination of component A and component B; component A comprises a prepolymer containing a crystalline structure; component B comprises a chain extender containing a branched structure, and the chain extender containing a branched structure is obtained by reacting a branched diol with a first aliphatic diisocyanate.

[0008] The polyurethane composition provided by the present invention includes two components, wherein component A is a prepolymer with a crystalline structure (containing NCO groups), and component B includes a chain extender with a branched structure (containing OH). Through the design and compounding of two specific components, a polyurethane elastomer having a multiphase separation structure of a crystalline reinforcement part and a flexible segment aggregation phase is constructed. Specifically, when the components A and B undergo a curing reaction, the hard segment is hindered from being ordered due to the action of hydrogen bonds, and it is in a thermodynamically unbalanced state without time for phase separation, while the branched structure in component B is thermodynamically incompatible with the polyurethane molecule and has good softness. Therefore, on the one hand, it plays a lubricating role in the microphase separation process of the polyurethane at the distributed phase domain interface, and as an intermolecular lubricant, it effectively improves its own phase separation and improves the degree of microphase separation. At the same time, the polyol soft segment in the prepolymer with a crystalline structure makes the polyurethane molecular structure tend to be ordered, and the hard segment and the soft segment are more easily ordered to form. Phase separation ensures that the material maintains strong stability when subjected to stress; on the other hand, during the curing reaction, the branched structure with free movement at one end is interspersed in the polyurethane network, and when the material is damaged by the outside world, it can disperse the energy in the entire elastomer material, reducing local stress concentration; further, in the soft and hard phases of the polyurethane, the branched structure is thermodynamically incompatible with the polar polyol structure (from the prepolymer), and is more likely to form aggregation. One is that the branched structure is entangled in the interlayer structure of the chain segments after the polyurethane is cured, making the chain segments more compact, and the other is that the branched structure aggregates to form microphase separation, which plays a physical cross-linking and toughening role. The two effects work together to significantly increase the intermolecular force of the polyurethane, effectively disperse the stress when subjected to external force, thereby improving the mechanical properties of the polyurethane elastomer, obtaining high tensile strength while having excellent toughness.

[0009] Moreover, the component B includes a chain extender containing a branched structure, which can not only improve the strength and toughness of the polyurethane elastomer, but also improve the processing technology, prolong the operation time, and can be mixed with traditional polyurethane according to different product requirements to play a reinforcing role. The component B is a new type of polyurethane chain extender with universality and can be used in other polyurethane composite materials, providing a solution for polyurethane modification.

[0010] Preferably, the mass percentage of NCO groups in the prepolymer containing a crystalline structure is 6-10%, for example, it can be 6.2%, 6.5%, 6.8%, 7%, 7.2%, 7.5%, 7.8%, 8%, 8.2%, 8.5%, 8.8%, 9%, 9.2%, 9.5% or 9.8%, as well as specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively enumerates the specific point values ​​included in the range, and 6-9% is further preferred.

[0011] Preferably, the prepolymer containing a crystalline structure is obtained by reacting a crystallizable polyol with a second isocyanate.

[0012] Preferably, the polyol includes any one or a combination of at least two of polycaprolactone polyol, polytetramethylene glycol, polycarbonate polyol, and adipic acid polyester polyol, and more preferably any one or a combination of at least two of polycaprolactone polyol, polytetramethylene glycol, and adipic acid polyester polyol.

[0013] Illustratively, the adipic acid-based polyester polyol is obtained by reacting adipic acid with a diol, and the diol preferably includes 1,6-hexanediol; the adipic acid-based polyester polyol is preferably polyhexanediol adipate polyol.

[0014] Preferably, the number average molecular weight of the polyol is 2000-4000, for example, it can be 2100, 2300, 2500, 2700, 2900, 2000, 3100, 3300, 3500, 3700 or 3900, as well as specific values ​​between the above points. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific points included in the range, and 3000-4000 is further preferred.

[0015] As a preferred technical solution of the present invention, the prepolymer containing a crystalline structure is obtained by reacting a crystallizable polyol with a second isocyanate. The polyol preferably includes at least one of polycaprolactone polyol (PCL), polytetramethylene glycol (PTMG), and adipic acid-based polyester polyol. On the one hand, the prepolymer has excellent crystallizability, so that the prepolymer contains a crystalline structure. When compounded with a chain extender containing a branched structure, a specific phase state in which a multi-phase structure coexists can be formed. On the other hand, the polyol has excellent mechanical properties and can further improve the strength and toughness of the polyurethane elastomer.

[0016] Preferably, the second isocyanate includes aromatic diisocyanate and / or aliphatic diisocyanate, and more preferably aromatic diisocyanate.

[0017] Herein, the aliphatic diisocyanate includes chain aliphatic isocyanate and may also include cyclic aliphatic (also known as alicyclic) isocyanate.

[0018] Preferably, the aromatic diisocyanate includes any one of toluene diisocyanate, diphenylmethane diisocyanate, xylylene diisocyanate, and liquefied MDI, or a combination of at least two thereof; more preferably, toluene diisocyanate, diphenylmethane diisocyanate, and liquefied MDI, or a combination of at least two thereof.

[0019] Herein, the liquefied MDI is a modified diphenylmethane diisocyanate (modified MDI), and a liquid MDI modified product is obtained by introducing carbamate or carbodiimide groups into 4,4'-MDI; the aforementioned modification means are known in the art; the liquefied MDI can be obtained through commercial routes.

[0020] Preferably, the aliphatic diisocyanate includes any one of isophorone diisocyanate, dicyclohexylmethane diisocyanate, and hexamethylene diisocyanate, or a combination of at least two thereof.

[0021] Preferably, the temperature for the reaction of the crystallizable polyol with the second isocyanate is 60-100°C, for example, it may be 62°C, 65°C, 68°C, 70°C, 72°C, 75°C, 78°C, 80°C, 82°C, 85°C, 88°C, 90°C, 92°C, 95°C or 98°C, as well as specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively enumerates the specific point values ​​included in the range, and 70-80°C is further preferred.

[0022] Preferably, the reaction time of the crystallizable polyol and the second isocyanate is 2-8 h, for example, it can be 2.5 h, 3 h, 3.5 h, 4 h, 4.5 h, 5 h, 5.5 h, 6 h, 6.5 h, 7 h or 7.5 h, as well as specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively enumerates the specific point values ​​included in the range, and 4-5 h is further preferred.

[0023] Preferably, the reaction of the crystallizable polyol with the second isocyanate is carried out in a protective atmosphere.

[0024] Preferably, the protective atmosphere includes any one of a nitrogen atmosphere, an argon atmosphere, and a helium atmosphere, or a combination of at least two of them.

[0025] In the present invention, the material ratio of the crystallizable polyol to the second isocyanate is determined according to the functionality of the two and the mass percentage content (6-10%) of the NCO group in the prepolymer.

[0026] The reaction of the crystallizable polyol with the second isocyanate is optionally carried out in the presence of a catalyst and / or a solvent.

[0027] Preferably, the branched diol has a structure as shown in Formula I:

[0028] HO-R1-OH Formula I.

[0029] In Formula I, R1 is selected from any one of C2-C30 branched alkylene groups, for example, it can be C3, C4, C5, C6, C7, C8, C9, C10, C11, C13, C15, C17, C19, C20, C22, C25, C28, etc.

[0030] Preferably, said R1 is * represents the attachment site of the group.

[0031] R2 is selected from C1-C18 straight chain or branched alkyl, for example, it can be C2, C3, C4, C5, C6, C7, C8, C9, C10, C11, C12, C13, C14, C15, C16, C17 and the like, more preferably C3-C12 straight chain or branched alkyl, further preferably C3-C12 straight chain alkyl.

[0032] R3 is selected from C1-10 straight or branched alkylene, for example, C1, C2, C3, C4, C5, C6, C7, C8, C9 straight or branched alkylene, more preferably * represents the attachment site of the group.

[0033] Preferably, the branched diol has a structure as shown in Formula II:

[0034]

[0035] Wherein, the R2 has the same range as mentioned above, and is selected from C1-C18 straight chain or branched chain alkyl, more preferably C3-C12 straight chain or branched chain alkyl, and even more preferably C3-C12 straight chain alkyl.

[0036] As a preferred technical solution of the present invention, the branched diol has a structure as shown in Formula I, preferably has a structure as shown in Formula II, R2 is a branched structure, preferably an alkyl long chain containing a -CH2- structure, and the branched diol reacts with a first aliphatic diisocyanate to obtain a chain extender containing the aforementioned branched structure.

[0037] As a preferred technical solution of the present invention, the component B includes a chain extender containing a branched structure, which can not only improve the strength and toughness of the polyurethane elastomer, but also improve the processing technology, extend the operation time, and can be mixed with traditional polyurethane according to different product requirements to play a reinforcing role.

[0038] The working time refers to the time during which the composition does not harden and maintains sufficient fluidity for its use (eg, injection molding, RTM, thermal bonding).

[0039] Preferably, the branched diol includes any one of 1,1-butanediol, 1,1-pentanediol, 1,1-hexanediol, 1,1-octanediol, 1,1-decanediol, and 1,1-dodecanediol, or a combination of at least two thereof.

[0040] Preferably, the first aliphatic diisocyanate includes any one of methylenebis-4,4'-cyclohexyl diisocyanate, cyclohexyl diisocyanate, isophorone diisocyanate, propylene-1,2-diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, dodecyl-1,12-diisocyanate, cyclobutane-1,3-diisocyanate, cyclohexane-1,3-diisocyanate, cyclohexane-1,4-diisocyanate, methylcyclohexene diisocyanate, 2,2,4-trimethylhexane diisocyanate, and dicyclohexylmethane diisocyanate, or a combination of at least two thereof, and tetramethylene diisocyanate and / or hexamethylene diisocyanate are further preferred.

[0041] Preferably, the molar ratio of the first aliphatic diisocyanate to the branched diol is 1:(2-2.2), for example, it can be 1:2.01, 1:2.03, 1:2.05, 1:2.07, 1:2.09, 1:2.1, 1:2.11, 1:2.13, 1:2.15, 1:2.17 or 1:2.19, etc.

[0042] Preferably, the temperature for the reaction of the branched diol with the first aliphatic diisocyanate is 60-100°C, for example, 62°C, 65°C, 68°C, 70°C, 72°C, 75°C, 78°C, 80°C, 82°C, 85°C, 88°C, 90°C, 92°C, 95°C or 98°C, as well as specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively enumerates the specific point values ​​included in the range, and 85-95°C is further preferred.

[0043] Preferably, the reaction time of the branched diol and the first aliphatic diisocyanate is 2-10 h, for example, it can be 2.5 h, 3 h, 3.5 h, 4 h, 4.5 h, 5 h, 5.5 h, 6 h, 6.5 h, 7 h, 7.5 h, 8 h, 8.5 h, 9 h or 9.5 h, as well as specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively enumerates the specific point values ​​included in the range, and 6-8 h is further preferred.

[0044] Preferably, the reaction of the branched diol with the first aliphatic diisocyanate is carried out in a protective atmosphere.

[0045] Preferably, the protective atmosphere includes any one of a nitrogen atmosphere, an argon atmosphere, and a helium atmosphere, or a combination of at least two of them.

[0046] Preferably, the molar ratio of the NCO groups in component A to the OH groups in component B is 1:(0.9-0.98), for example, it can be 1:0.91, 1:0.92, 1:0.93, 1:0.94, 1:0.95, 1:0.96 or 1:0.97, etc.

[0047] Preferably, the polyurethane composition further comprises additives and / or fillers.

[0048] Preferably, the polyurethane composition further comprises additives to meet the performance requirements of different products.

[0049] Preferably, the additives include any one or a combination of at least two of an internal release agent, a flame retardant, a pigment, an antistatic agent, an antioxidant, a UV stabilizer, a defoamer, a coupling agent, a leveling agent, a water scavenger, a molecular sieve, a thixotropic agent, and a plasticizer.

[0050] Preferably, the polyurethane composition further comprises a filler.

[0051] Preferably, the filler is an inorganic filler and / or an organic filler.

[0052] Preferably, the inorganic filler includes any one of siliceous minerals, metal oxides, metal salts, glass, glass fiber, carbon black, or a combination of at least two thereof.

[0053] Preferably, the siliceous mineral may be phyllosilicate, illustratively including but not limited to: any one of antigorite, bentonite, serpentine, hornblende, amphibole, chrysotile, talc, or a combination of at least two thereof.

[0054] Preferably, the metal oxide includes any one of kaolin, aluminum oxide, titanium oxide, zinc oxide, and iron oxide, or a combination of at least two thereof.

[0055] Preferably, the metal salt comprises chalk and / or barite.

[0056] Preferably, the organic filler comprises any one or a combination of at least two of melamine, rosin, cyclopentadiene resin, cyclopentadiene graft polymer, cellulose fiber, polyamide, polyacrylonitrile, polyurethane, polyester fiber based on aromatic and / or aliphatic dicarboxylic acid esters, and carbon fiber.

[0057] In a second aspect, the present invention provides a polyurethane elastomer, wherein the raw materials for preparing the polyurethane elastomer include the polyurethane composition as described in the first aspect.

[0058] The polyurethane elastomer provided by the present invention is formed by the curing reaction of component A and component B. A prepolymer containing a crystalline structure is subjected to a curing reaction with a chain extender containing a branched structure (preferably with an alkyl long chain as a branched chain), thereby constructing a polyurethane elastomer having a multiphase separation structure of a crystalline reinforcement part and a flexible segment aggregation phase. When the polyurethane is cured, the hard segment is hindered from being ordered due to the action of hydrogen bonds, and is in a thermodynamically unbalanced state without time for phase separation. The alkyl long chain of the -CH2- structure is thermodynamically incompatible with the polyurethane molecule and is very soft itself. Therefore, on the one hand, it plays a lubricating role in the microphase separation process of the polyurethane at the distributed phase domain interface, and as a molecular lubricant, it effectively improves its own phase separation and improves the degree of microphase separation. At the same time, the polyol having a crystalline structure The (polyether and / or polyester) soft segment makes the polyurethane molecular structure tend to be arranged in an orderly manner, and the hard segment and the soft segment are more likely to aggregate in an orderly manner to form phase separation, which ensures that the material maintains strong stability when subjected to stress; on the other hand, during curing, the alkyl chain at one end is interspersed in the polyurethane network. When the material is damaged by the outside world, it can effectively disperse the energy in the entire elastomer material and reduce local stress concentration; again, in the polyurethane soft and hard segment phase, the terminal alkyl long chain containing the -CH2- structure is thermodynamically incompatible with the polyether and / or polyester structure with a polar structure, and it is easier to form aggregation. One is that the alkyl side chain is entangled in the interlayer structure of the chain segment after the polyurethane is cured, making the chain segment more compact, and the other is that the alkyl chain aggregates to form microphase separation, which plays a role of physical crosslinking and toughening. Under these two effects, the intermolecular force of the polyurethane is increased, and when subjected to external force, the stress is effectively dispersed, the mechanical properties of the polyurethane elastomer are improved, and high tensile strength is obtained while having excellent toughness.

[0059] Preferably, the tensile strength of the polyurethane elastomer is ≥50 MPa, more preferably ≥55 MPa, and can reach 56-66 MPa.

[0060] Preferably, the tear strength of the polyurethane elastomer is ≥140 KN / m, more preferably ≥150 KN / m, further preferably ≥153 KN / m, and can reach 153-164 KN / m.

[0061] Preferably, the elongation at break of the polyurethane elastomer is ≥740%, further preferably ≥745%, more preferably ≥749%, and can reach 749-798%.

[0062] In a third aspect, the present invention provides a method for preparing the polyurethane elastomer as described in the second aspect, the preparation method comprising: mixing component A and component B and performing a curing reaction to obtain the polyurethane elastomer.

[0063] Preferably, the molar ratio of the NCO groups in component A to the OH groups in component B is 1:(0.9-0.98), for example, it can be 1:0.91, 1:0.92, 1:0.93, 1:0.94, 1:0.95, 1:0.96 or 1:0.97, etc.

[0064] Preferably, the mixing temperature is 80-90°C, for example, it can be 81°C, 82°C, 83°C, 84°C, 85°C, 86°C, 87°C, 88°C or 89°C, as well as specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0065] Preferably, the mixing is performed under stirring conditions so that component A and component B are fully mixed and uniform.

[0066] Preferably, the temperature of the curing reaction is 90-120°C, for example, it can be 92°C, 95°C, 98°C, 100°C, 102°C, 105°C, 108°C, 110°C, 112°C, 115°C or 118°C, as well as specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range, and 100-110°C is further preferred.

[0067] Preferably, the curing reaction time is 15-25h, for example, it can be 16h, 17h, 18h, 19h, 20h, 21h, 22h, 23h or 24h, as well as specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0068] Compared with the prior art, the present invention has the following beneficial effects:

[0069] In the polyurethane composition provided by the present invention, a specific multiphase structure is formed in the prepared polyurethane elastomer by designing and compounding the component A containing a crystalline structure and the component B having a branched structure, so that the polyurethane elastomer has both high strength and high toughness and excellent comprehensive performance. The present invention further optimizes the components and structures, so that the tensile strength of the polyurethane elastomer is ≥55MPa, the tear strength is ≥150KN / m, and the elongation at break is 749-798%, and has excellent comprehensive mechanical properties. DETAILED DESCRIPTION

[0070] The technical solution of the present invention is further described below by specific implementation methods. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0071] As used herein, the terms "comprises," "including," "having," "containing," or any other variation thereof, are intended to cover a non-exclusive inclusion. For example, a composition, process, method, article, or apparatus that comprises the listed elements is not necessarily limited to only those elements but may include other elements not expressly listed or inherent to such composition, process, method, article, or apparatus.

[0072] "Optionally" or "either" means that the subsequently described matter or event can or cannot occur, and that the description includes instances where the event occurs and instances where it does not.

[0073] The indefinite articles "a" and "an" before the elements or components of the present invention have no limitation on the quantity requirements (i.e. the number of occurrences) of the elements or components. Therefore, "a" or "an" should be interpreted as including one or at least one, and the elements or components in the singular form also include the plural form, unless the quantity obviously refers to the singular form only.

[0074] In the present invention, the features defined as "first" or "second" may include one or more of the features explicitly or implicitly, and are used to distinguish and describe the features, without distinction of order or importance. In the description of the present invention, unless otherwise specified, "plurality" means two or more.

[0075] In the following specific embodiments of the present invention, the raw materials used are described as follows:

[0076] (1) Crystallizable polyols

[0077] Polytetramethylene glycol, PTMG-2000, number average molecular weight 2000, BASF;

[0078] Polytetramethylene glycol, PTMG-3000, number average molecular weight 3000, Dalian Chemical Industry Co., Ltd., Taiwan, China;

[0079] Polycaprolactone polyol, PCL-3000, number average molecular weight 3000, Daicel Corporation;

[0080] Polycaprolactone polyol, PCL-4000, number average molecular weight 4000, Daicel Corporation;

[0081] Polyhexanediol adipate polyol, CTP-66, number average molecular weight 4000, Asahikawa Chemical Co.

[0082] (2) Other polyols

[0083] Propylene glycol ether polyol, C2040D, number average molecular weight 4000, Wanhua Chemical;

[0084] Propylene glycol ether polyol, C2020D, number average molecular weight 2000, Wanhua Chemical.

[0085] (3) Isocyanate

[0086] Toluene diisocyanate, TDI-100, NCO content 48.2 wt%, Wanhua Chemical Group Co., Ltd.

[0087] Diphenylmethane diisocyanate, MDI-100, NCO content 33.5 wt%, Wanhua Chemical Group Co., Ltd.;

[0088] Hexamethylene diisocyanate, HDI, Wanhua Chemical Group Co., Ltd.;

[0089] Dicyclohexylmethane diisocyanate, HMDI, Wanhua Chemical Group Co., Ltd.;

[0090] Tetramethylene diisocyanate, Wanhua Chemical Group Co., Ltd.

[0091] (4) Branched glycol

[0092] 1,1-Butanediol, Aladdin;

[0093] 1,1-Hexanediol, Aladdin;

[0094] 1,1-Octanediol, Aladdin;

[0095] 1,1-Dodecanediol, Aladdin.

[0096] (5) Other diols

[0097] 1,4-Butanediol, BASF.

[0098] In the following specific embodiments of the present invention, the test method for the mass percentage of NCO groups in the prepolymer is as follows:

[0099] The test was carried out using a Metrohm 905 potentiometric automatic titrator according to the method in standard GB / T 12009.4-2016.

[0100] In the following specific embodiments of the present invention, unless otherwise specified, "parts" and "%" are based on mass.

[0101] Example 1

[0102] A polyurethane composition comprises a combination of component A and component B; the component A is a prepolymer having a crystalline structure, obtained by reacting polytetramethylene glycol (PTMG) with diphenylmethane diisocyanate (MDI); the component B is a chain extender having a branched structure, obtained by reacting 1,1-butanediol with hexamethylene diisocyanate (HDI); the specific preparation method is as follows:

[0103] (1) Preparation of component A: 100 parts of MDI-100 and 236.6 parts of PTMG-2000 were reacted at 75° C. for 4 hours under nitrogen protection and stirring to obtain the prepolymer, wherein the mass percentage of NCO groups was 7%;

[0104] (2) Preparation of component B: HDI and 1,1-butanediol were added in a molar ratio of 1:2, and reacted at 90° C. for 6 h under nitrogen protection to obtain the chain extender.

[0105] A polyurethane elastomer, the raw material for its preparation is the polyurethane composition provided in this embodiment, and the preparation method comprises: feeding the materials with a molar ratio of NCO groups in component A to OH groups in component B of 1:0.95, fully mixing the two at 80° C. under stirring conditions, and curing reaction at 110° C. for 20 hours to obtain the polyurethane elastomer.

[0106] Example 2

[0107] A polyurethane composition comprises a combination of component A and component B; component A is a prepolymer having a crystalline structure, obtained by reacting polycaprolactone polyol (PCL) with MDI; component B is a chain extender having a branched structure, obtained by reacting 1,1-dodecanediol with HDI; the specific preparation method is as follows:

[0108] (1) Preparation of component A: 100 parts of MDI-100 and 236.1 parts of PCL-3000 were reacted at 80° C. for 5 h under nitrogen protection and stirring to obtain the prepolymer, wherein the mass percentage of NCO groups was 8%;

[0109] (2) Preparation of component B: HDI and 1,1-dodecanediol were added at a molar ratio of 1:2.1, and reacted at 95° C. for 8 h under nitrogen protection to obtain the chain extender.

[0110] A polyurethane elastomer, the raw material for its preparation is the polyurethane composition provided in this embodiment, and the preparation method comprises: feeding the components with a molar ratio of NCO groups in component A to OH groups in component B of 1:0.95, fully mixing the two components at 85° C. under stirring conditions, and curing reaction at 110° C. for 20 hours to obtain the polyurethane elastomer.

[0111] Example 3

[0112] A polyurethane composition comprises a combination of component A and component B; the component A is a prepolymer having a crystalline structure, obtained by reacting PCL with toluene diisocyanate (TDI); the component B is a chain extender having a branched structure, obtained by reacting 1,1-octanediol with HDI; the specific preparation method is as follows:

[0113] (1) Preparation of component A: 100 parts of TDI-100 and 518.9 parts of PCL-4000 were reacted at 80° C. for 4 hours under nitrogen protection and stirring to obtain the prepolymer, wherein the mass percentage of NCO groups was 6%;

[0114] (2) Preparation of component B: HDI and 1,1-octanediol were added at a molar ratio of 1:2, and reacted at 95° C. for 7.5 h under nitrogen protection to obtain the chain extender.

[0115] A polyurethane elastomer, wherein the raw material for preparation is the polyurethane composition provided in this embodiment, and the preparation method comprises: feeding the components with a molar ratio of NCO groups in component A to OH groups in component B of 1:0.95, fully mixing the two components at 90° C. under stirring conditions, and curing reaction at 100° C. for 20 hours to obtain the polyurethane elastomer.

[0116] Example 4

[0117] A polyurethane composition comprises a combination of component A and component B; the component A is a prepolymer having a crystalline structure, obtained by reacting PTMG with MDI; the component B is a chain extender having a branched structure, obtained by reacting 1,1-hexanediol with HDI; the specific preparation method is as follows:

[0118] (1) Preparation of component A: 100 parts of MDI-100 and 254.6 parts of PTMG-3000 were reacted at 70° C. for 5 h under nitrogen protection and stirring to obtain the prepolymer, wherein the mass percentage of NCO groups was 6%;

[0119] (2) Preparation of component B: HDI and 1,1-hexanediol were added in a molar ratio of 1:2, and reacted at 90° C. for 8 h under nitrogen protection to obtain the chain extender.

[0120] A polyurethane elastomer, the raw material for its preparation is the polyurethane composition provided in this embodiment, and the preparation method comprises: feeding the components with a molar ratio of NCO groups in component A to OH groups in component B of 1:0.95, fully mixing the two components at 85° C. under stirring conditions, and curing reaction at 110° C. for 20 hours to obtain the polyurethane elastomer.

[0121] Example 5

[0122] A polyurethane composition comprises a combination of component A and component B; component A is a prepolymer having a crystalline structure, obtained by reacting PCL with MDI; component B is a chain extender having a branched structure, obtained by reacting 1,1-octanediol with tetramethylene diisocyanate; the specific preparation method is as follows:

[0123] (1) Preparation of component A: 100 parts of MDI-100 and 236.1 parts of PCL-3000 were reacted at 80° C. for 5 h under nitrogen protection and stirring to obtain the prepolymer, wherein the mass percentage of NCO groups was 8%;

[0124] (2) Preparation of component B: Tetramethylene diisocyanate and 1,1-octanediol were added at a molar ratio of 1:2.2, and reacted at 105° C. for 8 hours under nitrogen protection to obtain the chain extender.

[0125] A polyurethane elastomer, the raw material for its preparation is the polyurethane composition provided in this embodiment, and the preparation method comprises: feeding the materials with a molar ratio of NCO groups in component A to OH groups in component B of 1:0.96, fully mixing the two at 89° C. under stirring conditions, and curing reaction at 110° C. for 24 hours to obtain the polyurethane elastomer.

[0126] Example 6

[0127] A polyurethane composition comprises a combination of component A and component B; component A is a prepolymer having a crystalline structure, obtained by reacting polyhexanediol adipate (CTP-66) with TDI; component B is a chain extender having a branched structure, obtained by reacting 1,1-hexanediol with HDI; the specific preparation method is as follows:

[0128] (1) Preparation of component A: 100 parts of MDI-100 and 220.7 parts of CTP-66 were reacted at 90° C. for 6 hours under nitrogen protection and stirring to obtain the prepolymer, wherein the mass percentage of NCO groups was 9%;

[0129] (2) Preparation of component B: HDI and 1,1-hexanediol were added at a molar ratio of 1:2.2, and reacted at 115° C. for 7 hours under nitrogen protection to obtain the chain extender.

[0130] A polyurethane elastomer, the raw material for its preparation is the polyurethane composition provided in this embodiment, and the preparation method comprises: feeding the materials with a molar ratio of NCO groups in component A to OH groups in component B of 1:0.93, fully mixing the two at 85° C. under stirring conditions, and curing reaction at 110° C. for 23 hours to obtain the polyurethane elastomer.

[0131] Example 7

[0132] A polyurethane composition comprises a combination of component A and component B; component A is a prepolymer having a crystalline structure, obtained by reacting PTMG with MDI; component B is a chain extender having a branched structure, obtained by reacting 1,1-octanediol with HMDI; the specific preparation method is as follows:

[0133] (1) Preparation of component A: 100 parts of MDI-100 and 254.6 parts of PTMG-3000 were reacted at 70° C. for 5 h under nitrogen protection and stirring to obtain the prepolymer, wherein the mass percentage of NCO groups was 6%;

[0134] (2) Preparation of component B: HMDI and 1,1-hexanediol were added at a molar ratio of 1:2.1, and reacted at 120° C. for 8 h under nitrogen protection to obtain the chain extender.

[0135] A polyurethane elastomer, the raw material for its preparation is the polyurethane composition provided in this embodiment, and the preparation method comprises: feeding the materials with a molar ratio of NCO groups in component A to OH groups in component B of 1:0.9, fully mixing the two at 90° C. under stirring conditions, and curing reaction at 110° C. for 25 hours to obtain the polyurethane elastomer.

[0136] Comparative Example 1

[0137] A polyurethane composition comprises a combination of component A and component B; the component A is a prepolymer containing a crystalline structure, and the raw materials and preparation method are the same as those of component A in Example 1; the component B is a chain extender 1,4-butanediol.

[0138] A polyurethane elastomer, the raw material for its preparation is the polyurethane composition provided in this comparative example, and the preparation method comprises: feeding the materials with a molar ratio of NCO groups in component A to OH groups in component B of 1:0.95, fully mixing the two at 85° C. under stirring conditions, and curing reaction at 110° C. for 20 hours to obtain the polyurethane elastomer.

[0139] Comparative Example 2

[0140] A polyurethane composition comprises a combination of component A and component B; component A is a prepolymer obtained by reacting polyoxypropylene ether polyol with TDI; component B is a chain extender containing a branched structure obtained by reacting 1,1-octanediol with HDI; the specific preparation method is as follows:

[0141] (1) Preparation of component A: 100 parts of TDI-100 and 518.9 parts of C2040D were reacted at 80° C. for 4 hours under nitrogen protection and stirring to obtain the prepolymer, wherein the mass percentage of NCO groups was 6%;

[0142] (2) Preparation of component B: HDI and 1,1-octanediol were added at a molar ratio of 1:2, and reacted at 95° C. for 7.5 h under nitrogen protection to obtain the chain extender.

[0143] A polyurethane elastomer, the raw material for its preparation is the polyurethane composition provided in this comparative example, and the preparation method comprises: feeding the materials with a molar ratio of NCO groups in component A to OH groups in component B of 1:0.95, fully mixing the two at 90° C. under stirring conditions, and curing reaction at 100° C. for 20 hours to obtain the polyurethane elastomer.

[0144] Comparative Example 3

[0145] A polyurethane composition comprises a combination of component A and component B; the component A is a prepolymer obtained by reacting polyoxypropylene ether polyol with MDI; the component B is a chain extender 1,4-butanediol; the specific preparation method is as follows:

[0146] (1) Preparation of component A: 100 parts of MDI-100 and 236.6 parts of C2020D were reacted at 75° C. for 5 h under nitrogen protection and stirring to obtain the prepolymer, wherein the mass percentage of NCO groups was 7%;

[0147] (2) Preparation of component B: 1,4-butanediol.

[0148] A polyurethane elastomer, the raw material for its preparation is the polyurethane composition provided in this comparative example, and the preparation method comprises: feeding the materials with a molar ratio of NCO groups in component A to OH groups in component B of 1:0.95, fully mixing the two at 80° C. under stirring conditions, and curing reaction at 100° C. for 20 hours to obtain the polyurethane elastomer.

[0149] Comparative Example 4

[0150] A polyurethane composition comprises a combination of component A and component B; the component A is a prepolymer containing a crystalline structure, and the raw materials and preparation method are the same as those of component A in Example 1; the component B is a chain extender 1,1-butanediol.

[0151] A polyurethane elastomer, the raw material for its preparation is the polyurethane composition provided in this comparative example, and the preparation method comprises: feeding the materials with a molar ratio of NCO groups in component A to OH groups in component B of 1:0.95, fully mixing the two at 80° C. under stirring conditions, and curing reaction at 110° C. for 20 hours to obtain the polyurethane elastomer.

[0152] Comparative Example 5

[0153] A polyurethane composition comprises a combination of component A and component B; the component A is a prepolymer having a crystalline structure, obtained by reacting PTMG with MDI; the component B is a chain extender having a branched structure, obtained by reacting 1,1-hexanediol with MDI; the specific preparation method is as follows:

[0154] (1) Preparation of component A: 100 parts of MDI and 254.6 parts of PTMG-3000 were reacted at 70° C. for 5 h under nitrogen protection and stirring to obtain the prepolymer, wherein the mass percentage of NCO groups was 6%;

[0155] (2) Preparation of component B: MDI-100 and 1,1-hexanediol were added in a molar ratio of 1:2, and reacted at 90° C. for 8 h under nitrogen protection to obtain the chain extender.

[0156] A polyurethane elastomer, the raw material for its preparation is the polyurethane composition provided in this comparative example, and the preparation method comprises: feeding the materials with a molar ratio of NCO groups in component A to OH groups in component B of 1:0.95, fully mixing the two at 85° C. under stirring conditions, and curing reaction at 110° C. for 20 hours to obtain the polyurethane elastomer.

[0157] The performance test of the polyurethane elastomers provided in Examples 1-7 and Comparative Examples 1-5 was performed, and the specific method included:

[0158] (1) Tensile strength and elongation at break: tested using a Zwick Z005 testing machine in accordance with the method in standard GB / T528-2009;

[0159] (2) Tear strength: tested using a Zwick Z005 testing machine in accordance with the method in standard GB / T 529-2008;

[0160] The test results are shown in Table 1:

[0161] Table 1

[0162]

[0163]

[0164] According to the performance test results in Table 1, the present invention, through the design and mutual compounding of component A containing a crystalline structure and component B having a branched structure, makes the polyurethane elastomer have both excellent mechanical properties and excellent toughness, and its tensile strength is 51-66MPa, tear strength is 143-164KN / m, and elongation at break is 745-798%. In addition, combined with the performance test results of Examples 1-7, it can be seen that by designing a chain extender containing a branched structure in component B, especially by preparing a chain extender by reacting a straight-chain aliphatic diisocyanate with a branched diol (Examples 1-6), a polyurethane elastomer with better performance can be obtained.

[0165] Comparative Example 1 uses conventional 1,4-butanediol polyurethane chain extender. Compared with Example 1, its mechanical properties are significantly worse, but the toughness is not much different.

[0166] Compared with Example 3, Comparative Example 2 does not use the preferred polyol of the present invention, and the prepolymer does not contain a crystalline structure, so that the mechanical properties of Comparative Example 2 are lower than those of Example 3. The tensile strength and tear strength of the polyurethane elastomer described in Example 3 are significantly improved, and the toughness is almost not lost. At the same time, by comparing Comparative Example 2 with other comparative examples, it can be seen that Comparative Example 2 uses a chain extender containing a branched structure, so that its mechanical properties are significantly better than those of other comparative examples.

[0167] The raw materials used in Comparative Example 3 are completely different from those of the present invention. The polyurethane elastomer is prepared by reacting a prepolymer without a crystalline structure with a conventional chain extender. The mechanical properties are significantly different from those of Examples 1 to 6. In addition, by comparing Comparative Example 2 with Comparative Example 3, it can be seen that the mechanical properties of the polyurethane elastomer prepared by curing the chain extender of the present invention with a conventional prepolymer in Comparative Example 2 are not as significantly improved as those in the examples, but are improved to a certain extent compared with the mechanical properties of Comparative Example 3. It can be seen that the specific chain extender in the present invention plays an important role in improving the mechanical properties of the polyurethane elastomer.

[0168] The chain extender in Comparative Example 4 is 1,1-butanediol. Although the chain extender contains a branched structure, the mechanical properties of the polyurethane elastomer are significantly lower than those in Example 1, and even lower than those of the polyurethane elastomer using 1,4-butanediol as a chain extender in Comparative Example 1; the chain extender in Comparative Example 5 is formed by the reaction of 1,1-butanediol and aromatic diisocyanate MDI. Although it also contains a branched structure, the polyurethane elastomer prepared using it not only has a decreased mechanical strength, but also a significantly decreased elongation at break, and sacrifices toughness. It can be seen that the present invention plays an important role in improving the mechanical properties of polyurethane elastomers by designing a chain extender containing a specific branched structure formed by the reaction of a branched diol and an aliphatic diisocyanate. The specific chain extender and the prepolymer containing a crystalline structure are compounded and synergistic, which can give the polyurethane elastomer more excellent strength and toughness.

[0169] The applicant declares that the present invention uses the above-mentioned embodiments to illustrate the polyurethane composition, polyurethane elastomer and preparation method thereof, but the present invention is not limited to the above-mentioned embodiments, that is, it does not mean that the present invention must rely on the above-mentioned embodiments to be implemented. Those skilled in the art should understand that any improvement of the present invention, equivalent replacement of various raw materials of the product of the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A polyurethane elastomer, characterized in that: The raw materials for preparing the polyurethane elastomer include a polyurethane composition; The polyurethane composition comprises a combination of component A and component B; the component A comprises a prepolymer containing a crystalline structure; The prepolymer containing a crystalline structure is obtained by reacting a crystallizable polyol with a second isocyanate; The polyol is composed of any one of polycaprolactone polyol, polytetrahydrofuran polyol, and adipic acid polyester polyol, or a combination of at least two thereof; The component B includes a chain extender containing a branched structure, and the chain extender containing a branched structure is obtained by reacting a branched diol with a first aliphatic diisocyanate; The branched diol includes any one of 1,1-butanediol, 1,1-pentanediol, 1,1-hexanediol, 1,1-octanediol, 1,1-decanediol, and 1,1-dodecanediol, or a combination of at least two thereof; The prepolymer containing a crystalline structure contains an NCO group, and the chain extender containing a branched structure contains an OH group.

2. The polyurethane elastomer according to claim 1, characterized in that The mass percentage of NCO groups in the prepolymer containing a crystalline structure is 6-10%.

3. The polyurethane elastomer according to claim 1, characterized in that The number average molecular weight of the polyol is 2000-4000.

4. The polyurethane elastomer according to claim 3, characterized in that The number average molecular weight of the polyol is 3000-4000.

5. The polyurethane elastomer according to claim 1, characterized in that The second isocyanate includes aromatic diisocyanate and / or aliphatic diisocyanate.

6. The polyurethane elastomer according to claim 5, characterized in that The second isocyanate is an aromatic diisocyanate.

7. The polyurethane elastomer according to claim 5, characterized in that The aromatic diisocyanate includes any one of toluene diisocyanate, diphenylmethane diisocyanate, and xylylene diisocyanate, or a combination of at least two of them.

8. The polyurethane elastomer according to claim 7, characterized in that: The aromatic diisocyanate consists of toluene diisocyanate and / or diphenylmethane diisocyanate.

9. The polyurethane elastomer according to claim 5, characterized in that: The aliphatic diisocyanate includes any one of isophorone diisocyanate, dicyclohexylmethane diisocyanate, and hexamethylene diisocyanate, or a combination of at least two of them.

10. The polyurethane elastomer according to claim 1, characterized in that: The temperature for reacting the crystallizable polyol with the second isocyanate is 60-100°C.

11. The polyurethane elastomer according to claim 10, characterized in that: The temperature of the reaction of the crystallizable polyol with the second isocyanate is 70-80°C.

12. The polyurethane elastomer according to claim 1, characterized in that: The time for the reaction of the crystallizable polyol with the second isocyanate is 2-8 hours.

13. The polyurethane elastomer according to claim 12, characterized in that: The time for the crystallizable polyol to react with the second isocyanate is 4-5 hours.

14. The polyurethane elastomer according to claim 1, characterized in that The first aliphatic diisocyanate includes any one or a combination of at least two of methylene bis-4,4'-cyclohexyl diisocyanate, cyclohexyl diisocyanate, isophorone diisocyanate, propylene-1,2-diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, dodecyl-1,12-diisocyanate, cyclobutane-1,3-diisocyanate, cyclohexane-1,3-diisocyanate, cyclohexane-1,4-diisocyanate, methylcyclohexene diisocyanate, 2,2,4-trimethylhexane diisocyanate, and dicyclohexylmethane diisocyanate.

15. The polyurethane elastomer according to claim 14, characterized in that The first aliphatic diisocyanate is tetramethylene diisocyanate and / or hexamethylene diisocyanate.

16. The polyurethane elastomer according to claim 1, characterized in that The molar ratio of the first aliphatic diisocyanate to the branched diol is 1:(2-2.2).

17. The polyurethane elastomer according to claim 1, characterized in that The temperature for reacting the branched diol with the first aliphatic diisocyanate is 60-100°C.

18. The polyurethane elastomer according to claim 17, characterized in that The temperature for reacting the branched diol with the first aliphatic diisocyanate is 85-95°C.

19. The polyurethane elastomer according to claim 1, characterized in that: The reaction time of the branched diol and the first aliphatic diisocyanate is 2-10 hours.

20. The polyurethane elastomer according to claim 19, characterized in that The reaction time of the branched diol and the first aliphatic diisocyanate is 6-8 hours.

21. The polyurethane elastomer according to claim 1, characterized in that The molar ratio of the NCO groups in the component A to the OH groups in the component B is 1:(0.9-0.98).

22. The polyurethane elastomer according to claim 1, characterized in that The polyurethane composition further includes additives.

23. A method for preparing a polyurethane elastomer according to any one of claims 1 to 22, characterized in that: The preparation method comprises: mixing component A and component B and then performing a curing reaction to obtain the polyurethane elastomer.

24. The preparation method according to claim 23, characterized in that: The molar ratio of the NCO groups in the component A to the OH groups in the component B is 1:(0.9-0.98).

25. The preparation method according to claim 23, characterized in that: The mixing temperature is 80-90°C.

26. The preparation method according to claim 23, characterized in that: The curing reaction temperature is 90-120°C.

27. The preparation method according to claim 26, characterized in that: The curing reaction temperature is 100-110°C.

28. The preparation method according to claim 23, characterized in that: The curing reaction time is 15-25 h.

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