Fatigue-resistant polyurethane elastomer as well as preparation method and application thereof

Abstract

The embodiment of the invention relates to the technical field of high polymer materials, in particular to a fatigue-resistant polyurethane elastomer as well as a preparation method and application thereof. The anti-fatigue polyurethane elastomer is prepared from the following raw material components in parts by mass: 40 to 70 parts of isocyanate, 40 to 70 parts of an ether-containing compound, 4.7 to 25 parts of a chain extender, 0.4 to 3.5 parts of a cross-linking agent, 0.5 to 5 parts of an end-capping agent and 0.1 to 1.5 parts of a catalyst. Wherein the end-capping reagent comprises a fluorine-containing end-capping reagent, and the content of the fluorine element contained in the fatigue-resistant polyurethane elastomer is 0.1-1.5 wt%. According to the fatigue-resistant polyurethane elastomer, the content of fluorine and the ratio of fluorocarbon bonds to ether bonds are regulated and controlled, so that the fatigue-resistant polyurethane elastomer has good thermal stability, friction resistance, aging resistance and the like, and meanwhile, the fatigue-resistant polyurethane elastomer also has relatively high tensile strength and elongation at break and excellent fatigue resistance.

Description

Technical Field

[0001] The present invention belongs to the technical field of polymer materials, and specifically relates to a fatigue-resistant polyurethane elastomer and a preparation method and application thereof. Background Art

[0002] Folding soft muscles are an actuator commonly used in soft robots that converts changes in fluid pressure and volume into relative motion between end plates. Folding soft muscles include Figure 1 The corrugated tubular muscles shown and Figure 2 The origami muscle shown. In the process of the folded soft muscle converting the change of fluid pressure and volume into the relative movement between the end plates, the side wall of the folded soft muscle will change between the two states of bending and folding and stretching and flattening. Therefore, the general working condition of the folded soft muscle requires the material to have high hardness, strength, tear resistance, bending resistance and aging resistance, so that the folded soft muscle can withstand repeated bending, folding and stretching and flattening without failure phenomena such as leakage.

[0003] The common material for folding soft muscles is thermoplastic polyurethane elastomer, which is composed of hard segments and soft segments. It has viscoelastic properties and good processing performance and is widely used in shock absorption, transportation, pipelines and other fields. The hardness, tensile strength, elongation at break and tear strength of polyurethane materials can be adjusted by different proportions between soft segments such as polyols and polyethers and hard segments such as isocyanates in the main chain of polyurethane molecules.

[0004] During the dynamic use of polyurethane materials, the hardness of the material and its service life show a negative correlation. The greater the hardness, the worse the fatigue resistance of the material and the lower the service life. At present, the general life of folding soft muscles made of polyurethane materials is 500,000 times, which cannot meet the use requirements of soft robot applications. For example, in high temperature and high humidity working scenes such as the plum rain season in the south and steam in factories, the polyurethane materials commonly used in folding soft muscles show accelerated aging after long-term work, resulting in further reduction of their fatigue resistance. Summary of the invention

[0005] The purpose of the present application is to provide a fatigue-resistant polyester elastomer and a preparation method and application thereof, so as to solve the technical problems in the prior art that polyurethane materials are prone to aging and have poor fatigue resistance in high temperature, high humidity and other environments.

[0006] In the first aspect, the embodiment of the present application provides a fatigue-resistant polyurethane elastomer. The fatigue-resistant polyurethane elastomer includes the following raw material components by weight: 40 to 70 parts of isocyanate, 40 to 70 parts of ether-containing compounds, 10 to 25 parts of chain extenders, 0.5 to 3.5 parts of cross-linking agents, 1 to 5 parts of end-capping agents, and 0.1 to 1.5 parts of catalysts. Among them, the end-capping agent includes a fluorine-containing end-capping agent, and the content of fluorine element contained in the fatigue-resistant polyurethane elastomer is 0.2 to 1.5wt%.

[0007] The fatigue-resistant polyurethane elastomer in the embodiment of the present application has good thermal stability, friction resistance, aging resistance and other properties through the regulation of the mass fraction of raw materials and the content of fluorine element. It also has high tensile strength, tear elongation and good fatigue resistance.

[0008] In a second aspect, the present invention provides a method for preparing a fatigue-resistant polyurethane elastomer. The method comprises the following steps:

[0009] Prepolymerizing the ether-containing compound and isocyanate, or prepolymerizing the ether-containing compound, isocyanate and a catalyst to obtain a first prepolymer;

[0010] The first prepolymer is subjected to a chain extension treatment with a chain extender and a cross-linking agent to obtain a second prepolymer;

[0011] The second prepolymer is end-capped with an end-capping agent to obtain a fatigue-resistant polyurethane elastomer.

[0012] Among them, the mass fraction of isocyanate is 40 to 70 parts, the mass fraction of ether-containing compounds is 40 to 70 parts, the mass fraction of chain extender is 4.7 to 25 parts, the mass fraction of cross-linking agent is 0.4 to 3.5 parts, the mass fraction of end-capping agent is 0.5 to 5 parts, the mass fraction of catalyst is 0.1 to 1.5 parts, and the content of fluorine element in fatigue-resistant polyurethane elastomer is 0.2 to 1.5wt%.

[0013] The preparation method of the embodiment of the present application controls the preparation process, as well as the mass fraction of the raw materials and the fluorine content in the polyurethane elastomer, and the ratio of carbon-fluorine bonds and ether bonds, so that the prepared polyurethane elastomer has good aging resistance, tensile strength, tear strength and fatigue resistance.

[0014] In a third aspect, the embodiments of the present application provide applications of fatigue-resistant polyurethane elastomers in folding soft muscles, automobile tires, sports pulley equipment, wind turbine shock absorption, large water storage tanks, and photovoltaic module protective films. The fatigue-resistant polyurethane elastomer is the fatigue-resistant polyurethane elastomer of the present application or the fatigue-resistant polyurethane elastomer prepared by the method for preparing the fatigue-resistant polyurethane elastomer of the present application.

[0015] Based on the characteristics of the fatigue-resistant polyurethane elastomer in this application, such as good aging resistance, good wear resistance, high tensile strength, high tear strength, large elongation at break, good wear resistance, and good fatigue resistance such as folding resistance and bending resistance, the fatigue-resistant polyurethane elastomer has good mechanical properties and excellent service life when used in folding soft muscles, automobile tires, sports pulley equipment, wind turbine shock absorption, large water storage tanks, and photovoltaic module protective films. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the specific implementation methods of the present application or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0017] Figure 1 A schematic diagram of a bellows-type folded soft muscle in the prior art;

[0018] Figure 2 It is a schematic diagram of origami muscle-style folded soft muscle in the prior art;

[0019] Figure 3 This is a process flow chart for preparing fatigue-resistant polyurethane elastomer provided in an embodiment of the present application. DETAILED DESCRIPTION

[0020] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present application more clearly understood, the present application is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0021] In this application, the term "and / or" describes the association relationship of associated objects, indicating that there may be three relationships. For example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone. A and B can be singular or plural. The character " / " generally indicates that the associated objects are in an "or" relationship.

[0022] In this application, "at least one" means one or more, and "plurality" means two or more. "At least one of the following" or similar expressions refers to any combination of these items, including any combination of single items or plural items. For example, "at least one of a, b, or c", or "at least one of a, b, and c" can all mean: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, c can be single or multiple, respectively.

[0023] It should be understood that in the various embodiments of the present application, the size of the serial numbers of the above-mentioned processes does not mean the order of execution, some or all of the steps can be executed in parallel or sequentially, and the execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0024] The terms used in the embodiments of the present application are only for the purpose of describing specific embodiments, and are not intended to limit the present application. The singular forms "a", "said" and "the" used in the embodiments of the present application and the appended claims are also intended to include plural forms, unless the context clearly indicates other meanings.

[0025] The weight of the relevant components mentioned in the embodiment description of the present application can not only refer to the specific content of each component, but also represent the proportional relationship between the weights of the components. Therefore, as long as the content of the relevant components is proportionally enlarged or reduced according to the embodiment description of the present application, it is within the scope disclosed in the embodiment description of the present application. Specifically, the mass described in the embodiment description of the present application can be a mass unit known in the chemical industry such as μg, mg, g, kg, etc.

[0026] In a first aspect, the present embodiment provides a fatigue-resistant polyurethane elastomer, which comprises the following raw material components in parts by weight:

[0027] 40-70 parts of isocyanate;

[0028] Contains 40-70 parts of ether compounds;

[0029] 10-25 parts of chain extender;

[0030] 0.5 to 3.5 parts of cross-linking agent;

[0031] 1 to 5 parts of capping agent;

[0032] 0.1-1.5 parts of catalyst;

[0033] The end-capping agent includes a fluorine-containing end-capping agent, and the content of fluorine element contained in the fatigue-resistant polyurethane elastomer is 0.2-1.5wt%.

[0034] The fatigue-resistant polyurethane elastomer in the embodiment of the present application introduces fluorine element through a fluorine-containing end-capping agent, and at the same time, by regulating the mass fractions of isocyanate, ether-containing compounds, chain extenders, cross-linking agents, and end-capping agents, as well as regulating the content of fluorine element in the fatigue-resistant polyurethane elastomer, the fatigue-resistant polyurethane elastomer has good thermal stability, friction resistance, aging resistance and other properties, as well as high tensile strength and tear elongation, and has good fatigue resistance properties such as folding resistance and bending resistance.

[0035] The electronegativity of fluorine is as high as 4, the bond length of carbon-fluorine bond is short and the bond energy is high (485KJ / mol). When fluorine atoms are introduced into polyurethane materials, they form a shielding protection effect around the carbon-carbon main chain, which can further improve the heat resistance, wear resistance and chemical inertness of polyurethane materials. In addition, fluorine elements can also form hydrogen bonds with carbamate in polyurethane, enhance the interaction between polyurethane molecules, and improve the thermal stability, friction resistance, aging resistance, chemical corrosion resistance and other properties of polyurethane materials. However, the introduction of carbon-fluorine bonds as strong polar bonds into the molecular chain will increase the hardness of polyurethane materials, reduce the flexibility of polyurethane elastomers, and thus reduce the fatigue resistance of polyurethane materials such as folding resistance and bending resistance.

[0036] Ether bonds are chemical bonds composed of oxygen atoms and hydrocarbon groups, with a bond energy of 326KJ / mol. The bond energy and polarity of ether bonds are both smaller than those of carbon-fluorine bonds, and the steric hindrance of ether bond rotation is low. Introducing ether bonds into the molecular chain segments of polyurethane can increase the flexibility of the molecular chain, reduce the rigidity of polyurethane materials, and improve hydrolysis resistance and antibacterial capabilities. However, due to the low bond energy of ether bonds, polyurethane materials containing ether bonds are prone to poor wear resistance.

[0037] The fatigue-resistant polyurethane elastomer in the embodiment of the present application introduces carbon-fluorine bonds and ether bonds at the same time, and is combined with a specific mass fraction of a chain extender and a cross-linking agent, thereby overcoming the poor fatigue resistance of the material caused by the carbon-fluorine bonds, and compensating for the defect of poor wear resistance of the material caused by the ether bonds, thereby improving the comprehensive performance of the fatigue-resistant polyurethane elastomer, so that the fatigue-resistant polyurethane elastomer has good wear resistance, heat resistance, aging resistance and fatigue resistance, and broadens the application of the fatigue-resistant polyurethane elastomer.

[0038] In some embodiments, the isocyanate may be a polyisocyanate, and in further embodiments, the polyisocyanate may be regulated to be a diisocyanate containing two active -NCO groups. By regulating the isocyanate to contain two active -NCO groups and combining with an ether-containing compound, the molecular segments of the fatigue-resistant polyurethane elastomer are arranged in the form of hard segments and soft segments, thereby effectively adjusting the performance of the fatigue-resistant polyurethane elastomer.

[0039] In some embodiments, the isocyanate may be regulated to include at least one of an aromatic polyisocyanate, an aliphatic polyisocyanate, and an alicyclic polyisocyanate.

[0040] In a further embodiment, the isocyanate may include at least one of 1,4-cyclohexane diisocyanate, m-xylylene diisocyanate, 2,4-hexahydrotoluene diisocyanate, 2,4-diphenylmethane diisocyanate, dicyclohexylmethane 4,4'-diisocyanate, toluene-2,4-diisocyanate, 1,3-phenylene diisocyanate, 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, 1,5-naphthalene diisocyanate, 1,4-phenylene diisocyanate, 2,6-hexahydrotoluene diisocyanate, 2,4-dicyclohexylmethane diisocyanate, 1,6-hexamethylene diisocyanate, 1,10-decane diisocyanate, 1,3-cyclohexane diisocyanate, 3,5-dichlorophenyl isocyanate, 1,4-butane diisocyanate, and 1,5-pentane diisocyanate.

[0041] In a further embodiment, the isocyanate includes at least one of 1,10-decane diisocyanate, 1,4-cyclohexane diisocyanate, m-xylylene diisocyanate, 2,4-hexahydrotoluene diisocyanate, 2,4-diphenylmethane diisocyanate, dicyclohexylmethane 4,4'-diisocyanate, toluene-2,4-diisocyanate, 1,3-phenylene diisocyanate, 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, and 1,5-naphthalene diisocyanate.

[0042] The isocyanate contains a six-membered ring or a six-membered condensed ring structure and multiple active -NCO groups, which react with the ether-containing compound to extend the molecular chain segment to form a first prepolymer. The six-membered ring or six-membered condensed ring structure in the isocyanate molecular chain segment forms a hard segment in the fatigue-resistant polyurethane elastomer molecular chain, and cooperates with the ether-containing compound to effectively adjust the hardness, tensile strength, elongation at break, tear strength and other properties of the fatigue-resistant polyurethane elastomer.

[0043] In some embodiments, the isocyanate can be regulated to have a mass fraction of 40 to 70 parts. In a specific example, the mass fraction of the isocyanate can be regulated to be 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, and other typical but non-limiting mass fractions. The mass fraction of the isocyanate is regulated within this range to adjust the hardness of the fatigue-resistant polyurethane elastomer and improve the tensile strength, tear strength, bending resistance and other properties.

[0044] In some embodiments, the ether-containing compound includes active groups such as epoxy, hydroxyl and amino groups that can polymerize with isocyanate functional groups. When the active group in the ether-containing compound is a hydroxyl group, the ether-containing compound can be a polyether polyol, and when the active group in the ether-containing compound is an epoxy group, the ether-containing compound can be a glycidyl ether. It should be noted that the active groups in the same ether-containing compound molecule can be the same (for example, only epoxy or hydroxyl groups) or different (for example, both epoxy and hydroxyl groups).

[0045] The active groups in the ether-containing compound react with isocyanate to form polymer molecular chain segments with soft segments and hard segments connected alternately, and the molecular chain segments in the ether-containing compound form the soft segments in the polymer molecular chain segments.

[0046] In some embodiments, the ether-containing compound may include at least one of neopentyl glycol diglycidyl ether, pentaerythritol allyl ether, 1,4-butanediol diglycidyl ether, pentaerythritol glycidyl ether, diethylene glycol monopentyl ether, 1,6-hexanediol diglycidyl ether, neopentyl glycol bis(4-aminophenyl) ether, 1,4-butanediol bis(3-aminopropyl) ether, glycerol triglycidyl ether, and trimethylolpropane triglycidyl ether.

[0047] The ether-containing compound contains suitable ether bonds and molecular chain segment lengths. By compounding the ether-containing compound with isocyanate, and further compounding with a chain extender, a cross-linking agent and a capping agent, the toughness and elongation-to-break rate of the fatigue-resistant polyester elastomer are further improved, thereby improving fatigue resistance such as bending resistance.

[0048] In some embodiments, the active groups of the ether-containing compound can be two. Regulating the number of active groups in the polyurethane and the active hydrogen-containing compound is conducive to further accurately regulating the branching in the polymer molecular chain segment, and the fluctuation of polyurethane resins prepared from different batches is small, and the performance of each batch of polyurethane is relatively stable.

[0049] In some embodiments, the mass fraction of the ether-containing compound can be adjusted to 40 to 70 parts. In specific examples, the mass fraction of the ether-containing compound can be adjusted to 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70 and other typical but non-limiting mass fractions. The ether-containing compound acts as a soft segment in the molecular chain of the polyester elastomer, adjusts the content of ether bonds in the fatigue-resistant polyurethane elastomer, and improves the elongation at break, fatigue resistance and other properties of the fatigue-resistant polyurethane elastomer. The mass fraction of the ether-containing compound is regulated within the range, and the ether-containing compound is compounded with isocyanate, a cross-linking agent and a capping agent, so that the hardness of the fatigue-resistant polyurethane elastomer is not significantly changed, while the tensile strength, elongation at break, tear strength, fatigue resistance and heat resistance are significantly improved.

[0050] In some embodiments, the number of carbon atoms in the main chain of the chain extender can be regulated to be greater than or equal to 5 and less than or equal to 15. In a specific example, the number of carbon atoms in the main chain of the chain extender can be 5, 6, 7, 8, 9, 10, 11, and other typical but non-limiting carbon atoms. By regulating the number of carbon atoms in the chain extender to be within this range, the flexibility of the molecular chain of the fatigue-resistant polyurethane elastomer is further improved, thereby further improving the fatigue resistance of the fatigue-resistant polyurethane elastomer such as bending resistance and folding resistance during long-term use.

[0051] In some embodiments, the chain extender can be regulated to include at least one of 1,2-cyclopentanediol, 1,3-cyclopentanediol, 1,2-cyclohexanediol, 1,3-cyclohexanediol, 1,4-cyclohexanediol, 1,2-pentanediol, 1,4-pentanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, dipropylene glycol, diethylene glycol, triethylene glycol, tripropylene glycol, pentanediol, diethylene glycol, trimethylolpropane, and sorbitol.

[0052] In a further embodiment, the chain extender includes at least one of 1,2-cyclohexanediol, 1,3-cyclohexanediol, 1,4-cyclohexanediol, 1,8-octanediol, 1,9-nonanediol, sorbitol, and 1,7-heptanediol.

[0053] The chain extender is the above-mentioned compound, which effectively increases the proportion of soft segments in the fatigue-resistant polyurethane elastomer molecular chain and improves the flexibility of the molecular chain, thereby further improving the fatigue resistance of the fatigue-resistant polyurethane elastomer during long-term use, such as bending and folding.

[0054] In a further embodiment, the chain extender can be adjusted to be a diol. The chain extension treatment is performed using a diol as a chain extender, so that the generated molecular chain contains a carbamate chain segment, and the carbamate chain segment forms a hydrogen bond with the fluorine atom in the polyurethane elastomer, thereby increasing the bonding strength within the molecule, so that the tensile strength, tear strength and wear resistance of the fatigue-resistant polyurethane elastomer are significantly improved.

[0055] In some embodiments, the weight fraction of the chain extender can be adjusted to 4 to 40 parts. In specific examples, the weight fraction of the chain extender can be adjusted to 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, etc. Typical but non-limiting weight fractions. When the weight fraction of the chain extender is adjusted within this range, the flexibility of the molecular chain of the fatigue-resistant polyurethane elastomer is improved, and the elongation at break and fatigue resistance of the fatigue-resistant polyurethane elastomer are improved. At the same time, it is compounded with isocyanate, ether-containing compounds, crosslinking agents and end-capping agents, so that the hardness of the fatigue-resistant polyurethane elastomer is not significantly changed, while the tensile strength, elongation at break, wear resistance, tear strength, fatigue resistance and heat resistance are improved.

[0056] In some embodiments, the crosslinking agent may include at least one of polycaprolactone triol, galactitol, 1,2,6-hexanetriol, 1,2,3-butanetriol, 1,2,7-heptanetriol, 1,2,5-pentanetriol, 1,2,9-nonanetriol, 1,2,8-octantriol, 1,2,10-decanetriol, dipentaerythritol, tetrabromopentaerythritol, benzene-1,2,4,5-tetrol, tripentaerythritol, diethylenetriamine, pentamethyldipropylenetriamine, triethylenetetramine, and tribromocyclohexanetetramine. The crosslinking agent contains three or more hydroxyl groups or amino groups and other reagents containing active hydrogen, which react with the active -NCO groups in the prepolymer molecular chain to form a branched chain, thereby regulating the crosslinking degree of the fatigue-resistant polyurethane elastomer molecular chain, and further improving the tensile strength, wear resistance and other properties of the fatigue-resistant polyurethane elastomer.

[0057] In some embodiments, the mass fraction of the crosslinking agent can be adjusted to 0.2 to 3.5 parts. In specific examples, the mass fraction of the crosslinking agent can be adjusted to 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3.0, 3.1, 3.2, 3.3, 3.4, 3.5, and other typical but non-limiting mass fractions. By adjusting the mass fraction of the crosslinking agent within this range, the number of branches and the degree of crosslinking of the fatigue-resistant polyurethane elastomer can be further adjusted.

[0058] In some embodiments, the branch ratio of the fatigue-resistant polyurethane elastomer can be adjusted to 0.5-1.5%. In specific examples, the branch ratio of the fatigue-resistant polyurethane elastomer can be adjusted to 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1.0%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5% and other typical but non-limiting branch ratios. The branch ratio of the fatigue-resistant polyurethane elastomer is regulated within this range, which effectively improves the elongation at break of the fatigue-resistant polyurethane elastomer without significantly reducing the mechanical properties of the tensile strength. The introduction of branches in the polyurethane molecular chain segments and within the content range of the present invention improves the melt index, which helps the injection molding, molding and other processing processes of the material during the processing, and the fatigue life of the final polyurethane product is improved.

[0059] In some embodiments, the end-capping agent may include at least one of active hydrogen compound reagents such as fluorinated isocyanates, fluorinated alcohol compounds, fluorinated phenol compounds, fluorinated amine compounds, fluorinated carboxylic acid compounds, fluorinated aldehyde compounds, and fluorinated ester compounds.

[0060] In some embodiments, the fluorinated isocyanate may include 2-fluorophenyl isocyanate, 2-fluoro-5-methylphenyl isocyanate, 3-(trifluoromethyl)phenyl isocyanate, 2-p-fluoroisocyanate, trifluoroacetyl isocyanate, 2-(trifluoromethoxy)phenyl isocyanate, 4-bromo-2,6-difluorophenyl isocyanate, 2-(difluoromethoxy)phenyl isocyanate, 4-fluorophenylethyl isocyanate, 3,5-difluorophenyl isocyanate, 2,6-difluorophenyl isocyanate, 3-fluorophenylthioisocyanate, 2-fluorophenylethyl isocyanate, 2,4-difluorophenyl isocyanate, 2-(trifluoromethyl)phenyl isocyanate, 3-(trifluoromethyl)phenyl isocyanate , 4-fluoro-2-nitrophenyl isocyanate, 4-fluorophenyl isocyanate, 3-chloro-4-fluorophenyl isocyanate, 2,3,5,6-tetrafluorophenylthioisocyanate, 2-methyl-3-fluorophenyl isocyanate, 4-fluoro-3-methylphenyl isocyanate, trifluoromethoxyphenyl isocyanate, 4-bromo-2-fluorophenyl isocyanate, 4-fluoro-3-nitrophenyl isocyanate, pentafluorophenylthioisocyanate, 2,3,4-trifluorophenylthioisocyanate, 3-fluoro-4-methylphenyl isocyanate, triphenylthiophosphorothioate, 2,5-difluorophenyl isocyanate, 5-fluoro-2-methylphenyl isocyanate, and at least one of 4-fluorophenylsulfonyl isocyanate.

[0061] In some embodiments, the fluorine-containing alcohol compound may include at least one of boron trifluoride isopropanol, 1,1,1,3,3,3-hexafluoro-2-propanol, 2-vinylhexafluoroisopropanol, 2-(4-amino-3-methylphenyl)perfluoroisopropanol, 1,1,1-trifluoro-2-propanol, 4-fluoro-3-(trifluoromethyl)benzyl alcohol, perfluorobutanol, 4-fluorobenzyl alcohol, haloperidol, 2-fluoroethanol, and hexafluorobutanol.

[0062] In a further embodiment, the fluorine-containing alcohol compound includes at least one of 2-vinylhexafluoroisopropanol, 1,1,1,3,3,3-hexafluoro-2-propanol, 1,1,1-trifluoro-2-propanol, and perfluorobutanol.

[0063] In some embodiments, the fluorine-containing phenol compound may include at least one of 2-fluoro-5-(trifluoromethyl)phenol, 3-fluoro-4-(trifluoromethoxy)phenol, 5-fluorothiophenol, 4-fluorophenol, 2,3,5,6-tetrafluoro-4-(trifluoromethyl)phenol, 3-fluorothiophenol, 2,3,5,6-tetrafluoro-4-(trifluoromethyl)thiophenol, 3-fluorophenol, 2-fluorophenol, pentafluorothiophenol, 2-fluorophenol, and 5-fluorophenol.

[0064] In a further embodiment, the fluorine-containing phenol compound includes at least one of 2-fluoro-5-(trifluoromethyl)phenol, 3-fluoro-4-(trifluoromethoxy)phenol, 2,3,5,6-tetrafluoro-4-(trifluoromethyl)phenol, 5-fluorothiophenol, and 2,3,5,6-tetrafluoro-4-(trifluoromethyl)thiophenol.

[0065] In some embodiments, the fluorine-containing amine compound may include at least one of 4-fluoro-2,3-fluoromethylpropylamine, 2-fluoro-5-trifluoromethylpropylamine, 3-fluoro-5-trifluoromethylaniline, 2-fluoro-6-trifluoromethylaniline, 4-amino-2-trifluorotoluene, 4-fluoro-3-trifluoromethylaniline, 2-fluoro-3 (trifluoromethyl)aniline, 4-fluoro-2-(trifluoromethyl)benzylamine, 2,5-difluoro-4-(trifluoromethyl)aniline, 2-fluoro-3-(trifluoromethyl)benzylamine, 1-fluoroamine, m-fluorophenylethylamine, o-fluoroaniline, 3-fluoroaniline, 2,3,5,6-tetrafluoro-4-trifluoromethylaniline, o-fluorophenylethylamine, 4-fluorobenzylamine, 3-fluorobenzylamine, 2-fluorobenzylamine, 4-fluoroacetanilide, 4-bromo-2-fluoro-5-(trifluoromethyl)aniline, 2-fluoroamide, and 4-fluorobenzamide.

[0066] In a further embodiment, the fluorine-containing amine compound includes at least one of 3-fluoro-5-trifluoromethylaniline, 2-fluoro-6-trifluoromethylaniline, 2,5-difluoro-4-(trifluoromethyl)aniline, 2,3,5,6-tetrafluoro-4-trifluoromethylaniline, and 4-bromo-2-fluoro-5-(trifluoromethyl)aniline.

[0067] In some embodiments, the fluorine-containing carboxylic acid compound may include fluoroboric acid, fluorosilicic acid, 2-fluoro-4-trifluoromethylbenzoic acid, 5-fluoro-2-(trifluoromethyl)benzoic acid, 2-fluoro-6-(trifluoromethyl)phenylacetic acid, trifluoroacetyl trifluoromethanesulfonate, p-fluorophenylacetic acid, 3-fluorobenzoic acid, 4-fluorocinnamic acid, 2-fluorobenzoic acid, o-fluorophenylacetic acid, 3-fluorophenylacetic acid, 3-fluoro-4-trifluoromethylbenzoic acid, 3-fluoro-5-(trifluoromethyl)benzoic acid, tetrafluoroterephthalic acid, perfluorooctanoic acid, 5-fluorosalicylic acid, 2-fluoro- At least one of 4-(trifluoromethyl)pyridine-3-carboxylic acid, pentafluoropropionic acid, heptafluorobutyric acid, hexafluorophosphoric acid, pentafluorobenzoic acid, 4-fluorosalicylic acid, 3-fluorosalicylic acid, perfluorohexanoic acid, perfluorodecanoic acid, 4-fluoroanthranilic acid, tetrafluorosuccinic acid, heptadecafluorononanoic acid, 3-fluorophenylboric acid, heptafluorobutyric acid, p-fluorobenzoic acid, 2-fluoro-6-(trifluoromethyl)benzoic acid, nonafluoropentanoic acid, 2-fluorocinnamic acid, 3,3,3-trifluoro-2-hydroxy-2-(trifluoromethyl)propionic acid, tridecafluoroheptanoic acid, octafluoroadipic acid, and p-fluorobenzoic acid.

[0068] In a further embodiment, the fluorine-containing carboxylic acid compound includes at least one of fluorosilicic acid, pentafluoropropionic acid, 5-fluoro-2-(trifluoromethyl)benzoic acid, hexafluorophosphoric acid, trifluoroacetyl trifluoromethanesulfonate, perfluorooctanoic acid, heptafluorobutyric acid, perfluorohexanoic acid, perfluorodecanoic acid, and nonafluoropentanoic acid.

[0069] In some embodiments, the fluorine-containing aldehyde compound may include at least one of 4-fluoro-2-trifluoromethylbenzaldehyde, 4-fluoro-3-trifluoromethylbenzaldehyde, 5-fluorosalicylaldehyde, and 4-fluoro-2-formylpyridine.

[0070] In some embodiments, the fluorine-containing ester compound may include at least one of tetramethylfluorouronium hexafluorophosphate, ethyl fluoroacetate, methyl 2-fluoronicotinate, and ethyl p-fluorobenzoate.

[0071] The above-mentioned fluorinated isocyanates, fluorinated alcohol compounds, fluorinated phenol compounds, fluorinated amine compounds, fluorinated carboxylic acid compounds, fluorinated aldehyde compounds and fluorinated ester compounds contain fluorine elements, and at the same time contain active groups such as isocyanate groups, hydroxyl groups, phenolic hydroxyl groups, amino groups, carboxyl groups, etc., which can react with the -NCO groups, hydroxyl groups, epoxy groups and other groups in the above-mentioned isocyanates, ether-containing compounds or chain extenders, so as to introduce fluorine-containing groups into the fatigue-resistant polyurethane elastomer. Through the introduction of fluorine elements, combined with the ether bonds, the number of side chains, and the ratio of hard segments and soft segments in the fatigue-resistant polyurethane elastomer molecules, the fatigue-resistant polyurethane elastomer has the characteristics of good wear resistance, good heat resistance, high tensile strength, high tear strength and fatigue resistance.

[0072] In some embodiments, the end-capping agent may include a fluorine-containing end-capping agent and a non-fluorine-containing end-capping agent. Further, the non-fluorine-containing end-capping agent may include at least one of dicyclohexylmethane 4,4'-diisocyanate, 1,6-hexamethylene diisocyanate, trichloroacetyl isocyanate, octadecyl isocyanate, m-toluene isocyanate, m-chlorophenyl isocyanate, o-chlorophenyl isocyanate, and cycloheptyl isocyanate.

[0073] In some embodiments, the weight fraction of the end-capping agent can be adjusted to be 0.5 to 3.0 parts. In specific examples, the weight fraction of the end-capping agent can be adjusted to be 0.5, 0.6, 0.7, 0.7, 0.9, 1.0, 1.1, 12, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.2, 2.4, 2.6, 2.8, 3.0, 3.2, 3.4, 3.6, 3.8, 4.0, 4.2, 4.4, 4.6, 4.8, 5.0, and other typical but non-limiting weight fractions. The end-capping agent is within this range, thereby regulating the content of fluorine in the fatigue-resistant polyurethane elastomer. At the same time, the type and mass fraction of the ether-containing compound are combined to regulate the ratio of ether bonds to carbon-fluorine bonds in the fatigue-resistant polyester elastomer according to the design requirements of the molecular chain, so that the fatigue-resistant polyester elastomer has good tensile strength without a significant change in hardness, and also has good wear resistance, heat resistance, aging resistance and fatigue resistance.

[0074] In some embodiments, the catalyst can be selected to include at least one of dimethylethanolamine, triethylamine, triethylenediamine, dimethylaminoethyl ether, methyldiethanolamine, dimethylaminoethoxyethanol, N,N-dimethylbenzylamine, 1,2-dimethylimidazole, tetramethylethylenediamine, N,N-diethylethanolamine, tetramethyldipropylenetriamine, trimethylhydroxyethylpropylenediamine, bis(dimethylaminopropyl)isopropanolamine, N-(dimethylaminopropyl)diisopropanolamine, and dimethylaminoethoxyethanol. In a further embodiment, the regulating catalyst includes at least one of dimethylaminoethyl ether, methyldiethanolamine, dimethylaminoethoxyethanol, N,N-dimethylbenzylamine, and tetramethylethylenediamine. The addition of the catalyst effectively reduces the reaction energy barrier of raw materials such as isocyanates, ether-containing compounds, and polyols, promotes the polymerization reaction, and shortens the reaction time.

[0075] In some embodiments, the raw materials of the fatigue-resistant polyurethane elastomer may also include a catalyst having a mass fraction of 0.1 to 1.5 parts. In a further embodiment, the mass fraction of the catalyst may be 0.3 to 1.5 parts. In a specific exemplary embodiment, the mass fraction of the catalyst may be regulated to be 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, and other typical but non-limiting mass fractions. By regulating the content of the catalyst within this range, the effect of the catalyst on the structure, mechanical properties, wear resistance, and other aspects of the fatigue-resistant polyurethane elastomer is effectively reduced, thereby further improving the mechanical properties, wear resistance, and other properties of the fatigue-resistant polyurethane elastomer.

[0076] In some embodiments, on the basis that the fluorine content in the fatigue-resistant polyurethane elastomer is 0.2-1.5wt%, the fluorine content can be further adjusted to 0.2-1.2wt%. In specific examples, the mass content of the fluorine element can be adjusted to 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1.0%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5% and other typical but non-limiting mass contents. The mass content of the fluorine element in the fatigue-resistant polyurethane elastomer is within this range, which effectively improves the tensile strength, friction resistance and other mechanical properties of the fatigue-resistant polyurethane elastomer, and at the same time improves the thermal stability, aging resistance, chemical corrosion resistance and other properties.

[0077] In some embodiments, the ratio of ether bonds to carbon-fluorine bonds in the fatigue-resistant polyurethane elastomer can be adjusted to be 7: 1 to 43: 1. In specific examples, the ratio of ether bonds to carbon-fluorine bonds in the fatigue-resistant polyurethane elastomer can be adjusted to be 7: 1, 8: 1, 9: 1, 10: 1, 11: 1, 12: 1, 13: 1, 14: 1, 15: 1, 16: 1, 17: 1, 18: 1, 19: 1, 20: 1, 21: 1, 22: 1, 23: 1, 24: 1, 25: 1, 26: 1, 27: 1, 28: 1, 29: 1, 30: 1, 31: 1, 32: 1, 33: 1, 34: 1, 35: 1, 36: 1, 37: 1, 38: 1, 39: 1, 40: 1, 41: 1, 42: 1, 43: 1, and other typical but non-limiting ratios. By regulating the ratio of ether bonds and carbon-fluorine bonds in the fatigue-resistant polyurethane elastomer within this range, taking into account the effects of ether bonds and carbon-fluorine bonds, and combining the hard segments, soft segments and side chains in the molecular chain segments of the fatigue-resistant polyurethane elastomer, the mechanical properties of aging resistance, tensile strength, elongation at break, wear resistance, tear strength and fatigue resistance of the fatigue-resistant polyurethane elastomer are significantly increased without significantly increasing the hardness.

[0078] In a second aspect, the present application provides a method for preparing polyurethane. Figure 3 As shown, the preparation method of the polyurethane comprises the following steps:

[0079] S01, prepolymerizing the ether-containing compound and isocyanate, or prepolymerizing the ether-containing compound, isocyanate and a catalyst to obtain a first prepolymer;

[0080] S02, subjecting the first prepolymer to a chain extension treatment with a chain extender and a cross-linking agent to obtain a second prepolymer;

[0081] S03, performing end-capping treatment on the second prepolymer and the end-capping agent to obtain a fatigue-resistant polyurethane elastomer.

[0082] Among them, the mass fraction of isocyanate is 40 to 70 parts, the mass fraction of ether-containing compounds is 40 to 70 parts, the mass fraction of chain extender is 4.7 to 25 parts, the mass fraction of cross-linking agent is 0.4 to 3.5 parts, the mass fraction of end-capping agent is 0.5 to 5 parts, the mass fraction of catalyst is 0.1 to 1.5 parts, and the content of fluorine element in fatigue-resistant polyurethane elastomer is 0.2 to 1.5wt%.

[0083] The preparation method of the embodiment of the present application polymerizes ether-containing compounds and isocyanates through prepolymerization to form a first prepolymer containing soft segments and hard segments in the molecular chain segments. The first prepolymer is then modified through chain extension and end-capping to obtain a fatigue-resistant polyurethane elastomer. The preparation method controls the mass fractions of ether-containing compounds and isocyanates, the mass fractions of chain extenders and cross-linking agents in the prepolymerization treatment, so that the fatigue-resistant polyurethane elastomer obtained has good tensile strength, tear strength, aging resistance, folding resistance and other fatigue resistance properties.

[0084] It should be noted that the ether-containing compounds, isocyanates, chain extenders, cross-linking agents and end-capping agents in the preparation method of the embodiments of the present application are the ether-containing compounds, isocyanates, chain extenders, cross-linking agents and end-capping agents mentioned above in the present application, and they will not be repeated here.

[0085] Step S01:

[0086] In step S01, a compound such as a polyol containing active hydrogen and isocyanate are prepolymerized, or a compound such as a polyol containing active hydrogen and isocyanate and a catalyst are prepolymerized to form a first prepolymer containing hard segments and soft segments in the molecular chain segments.

[0087] In the first prepolymer, the fragments formed after the polymerization of compounds such as polyols are soft segments, and the fragments formed by isocyanate polymers are hard segments. By regulating the types of compounds containing ether compounds and isocyanates and the mass fractions in the polymerization system, the molecular structure of the first prepolymer can be effectively adjusted, thereby further adjusting the fatigue resistance and hardness of the fatigue-resistant polyurethane elastomer, such as folding resistance and bending resistance.

[0088] In some embodiments, a catalyst may be added during the prepolymerization treatment in step S01. The catalyst is the catalyst described above in the present application and will not be described in detail herein. The addition of the catalyst can effectively reduce the reaction energy barrier of the prepolymerization treatment and improve the reaction activity.

[0089] In some embodiments, the prepolymerization process may include the following steps:

[0090] Step S011, subjecting the polyol compound containing active hydrogen and isocyanate to a first prepolymerization treatment to obtain a preliminary reaction system;

[0091] Step S012: subjecting the catalyst and the preliminary reaction system to a second prepolymerization treatment to obtain a first prepolymer.

[0092] In a further embodiment, the temperature of the first prepolymerization treatment can be controlled to be 60-90° C. and the time can be 0.5-1 hour. Through the first prepolymerization treatment, the ether-containing compound and the isocyanate in the preliminary reaction system are fully mixed, and the uniformity of the ether-containing compound and the isocyanate in the preliminary reaction system is improved, thereby improving the uniformity of the molecular weight in the first prepolymer obtained by the prepolymerization treatment.

[0093] In some embodiments, the temperature of the second prepolymerization treatment can be regulated to be 70-100° C. and the time can be 3-6 hours. By regulating the temperature and time of the second prepolymerization treatment within this range, the polymerization rate and degree of the ether compound and the isocyanate-containing polymer can be regulated, thereby regulating the molecular weight of the first prepolymer and the molecular chain length of the fatigue-resistant polyurethane elastomer, and regulating the fatigue resistance of the fatigue-resistant polyurethane elastomer, such as folding resistance and bending resistance.

[0094] Step S02:

[0095] In step S02, the first prepolymer prepared in step S01 is subjected to a chain extension treatment with a chain extender and a cross-linking agent, so that the molecular chain of the first prepolymer is extended and a branch is formed, thereby obtaining a second prepolymer.

[0096] Through the chain extension treatment, the side chain of the second prepolymer molecule is connected to a branch chain such as an ester group. Furthermore, short branches can be introduced into the fatigue-resistant polyurethane elastomer by combining the hydroxyl group of the polyol in the chain extender with the end-capping agent in the subsequent end-capping treatment. The introduction of branches on the main chain of the fatigue-resistant polyurethane elastomer allows the fatigue-resistant polyurethane elastomer to have good fluidity during high-temperature injection molding, which is beneficial to the processing of polyurethane elastomer products with thicker walls. In addition, the introduction of branches makes the stacking between the molecular chains of the fatigue-resistant polyurethane elastomer not tight, and the artificial muscle products prepared from the fatigue-resistant polyurethane elastomer molecules have better performance of permanent compression deformation during the positive and negative air pressure working process of -80-300Kpa. When the fatigue-resistant polyurethane elastomer is made into a folding soft muscle, the mechanical strength and service life of the folding soft muscle are effectively improved.

[0097] In some embodiments, the temperature of the chain extension treatment can be regulated to be 80 to 95°C and the time can be 3 to 12 hours. By regulating the temperature and time of the chain extension treatment within this range, the type and mass fraction of the chain extender and the cross-linking agent can be coordinated to effectively regulate the length of the soft segment in the second prepolymer molecular chain and the degree of cross-linking of the second prepolymer molecular chain, thereby improving the tensile strength, breaking strength, wear resistance and other mechanical properties of the fatigue-resistant polyurethane elastomer, and at the same time improving the fatigue resistance of the fatigue-resistant polyurethane elastomer, such as folding resistance.

[0098] Step S03:

[0099] Through step S03, the second prepolymer prepared in step S02 is subjected to end-capping treatment with an end-capping agent to prepare a fatigue-resistant polyurethane elastomer.

[0100] Through the end-capping treatment, the active groups such as hydroxyl groups on the second prepolymer molecular chain react with the active groups such as -NCO in the end-capping agent, so that the fluorine-containing groups in the end-capping agent are connected to the second prepolymer molecules to prepare a fatigue-resistant polyurethane elastomer. A carbon-fluorine bond is introduced into the fatigue-resistant polyurethane elastomer, and the carbon-fluorine bond forms a hydrogen bond with the carbamate, which increases the intermolecular force and improves the hydrolysis resistance, aging resistance, high temperature resistance, wear resistance and mechanical strength of the fatigue-resistant polyurethane elastomer.

[0101] In some embodiments, the temperature of the chain extension treatment can be adjusted to 60-90° C. and the time can be adjusted to 2-10 hours. The temperature and time of the end-capping treatment are adjusted within this range so that the end-capping agent can fully react with the second prepolymer, thereby improving the effect of the end-capping treatment and improving the hydrolysis resistance, aging resistance, high temperature resistance, wear resistance and mechanical strength of the fatigue-resistant polyurethane elastomer.

[0102] In the third aspect, the embodiments of the present application provide the application of fatigue-resistant polyurethane elastomer in folding soft muscles, automobile tires, sports pulley equipment, wind turbine shock absorption, large water storage tanks, and photovoltaic module protective films. The fatigue-resistant polyurethane elastomer is the fatigue-resistant polyurethane elastomer of the above-mentioned application.

[0103] Based on the characteristics of the fatigue-resistant polyurethane elastomer in this application, such as good aging resistance, good wear resistance, high tensile strength, high tear strength, large elongation at break, good wear resistance, and good fatigue resistance such as folding resistance and bending resistance, the fatigue-resistant polyurethane elastomer is applied to the folding soft muscles, automobile tires, sports pulley equipment, wind turbine shock absorption, large water storage tanks, and photovoltaic module protective films, and has a good service life.

[0104] Furthermore, fatigue-resistant polyurethane elastomers can also be used in surfboard panels and water storage tanks of rowing machines.

[0105] The fatigue-resistant polyurethane elastomer and its preparation method and application, etc. of the embodiment of the present application are illustrated by multiple specific embodiments.

[0106] Example 1

[0107] This embodiment provides a fatigue-resistant polyester elastomer, which includes the following raw material components: 46 parts of isocyanate, 47 parts of ether-containing compounds, 0.2 parts of catalysts, 19.7 parts of chain extenders, 4.5 parts of cross-linking agents, and 5.5 parts of end-capping agents. Among them, the isocyanate is 1,4-cyclohexane diisocyanate, the ether-containing compound is 1,6-hexanediol diglycidyl ether, the catalyst is dibutyltin dilaurate, the chain extender is 0.08 parts of 1,6-hexanediol and 0.12 parts of 1,3-cyclohexanediol, the cross-linking agent is 1.5 parts of 1,2,3-butanetriol and 3 parts of 1,2,7-heptanetriol, and the end-capping agent is boron trifluoride isopropanol.

[0108] The preparation process of the fatigue-resistant polyester elastomer of this embodiment is as follows:

[0109] Step S1 prepolymerization treatment: under nitrogen protection, add the dehydrated polyol and isocyanate into the reactor, stir and react at 60°C for 0.5h, then add the catalyst and stir and react at 70°C for 3h, lower the temperature to 40°C to form a first prepolymer.

[0110] Step S2: Chain extension treatment: adding a chain extender and a cross-linking agent to the first prepolymer obtained in the above step S1, stirring and reacting at 80° C. for 3 hours and then cooling to room temperature to obtain a second prepolymer;

[0111] Step S3: end-capping treatment: evacuate the reaction kettle of the second prepolymer obtained in step S2, add the end-capping agent, and react at 60° C. with stirring for 2 hours and then cool to room temperature to obtain a fatigue-resistant polyester elastomer.

[0112] Example 2 to Example 18

[0113] Embodiments 2 to 18 provide a fatigue-resistant polyester elastomer, respectively, wherein the fatigue-resistant polyester elastomer comprises isocyanate, ether-containing compound, chain extender, cross-linking agent, end-capping agent and catalyst in parts by mass as shown in Table 1. The specific compounds of isocyanate, ether-containing compound, chain extender, cross-linking agent, end-capping agent and catalyst in the fatigue polyester elastomer raw material are shown in Table 1.

[0114] The preparation method of the fatigue-resistant polyester elastomer is basically the same as that of Example 1, except that:

[0115] 1. In the prepolymerization treatment of step S1 in the preparation process of fatigue-resistant polyester elastomers in Examples 2 to 18, the stirring time and stirring temperature of the ether compound and isocyanate before adding the catalyst, the reaction time and reaction temperature after adding the catalyst, and the cooling temperature after the reaction are shown in Table 3.

[0116] 2. In the process of preparing fatigue-resistant polyester elastomers of Examples 2 to 18, the reaction time and reaction temperature after adding the chain extender and the cross-linking agent in step S2 chain extension treatment are shown in Table 3.

[0117] 3. In the process of preparing fatigue-resistant polyester elastomers of Examples 2 to 18, the reaction time and reaction temperature after adding the end-capping agent in step S3 end-capping treatment are shown in Table 3.

[0118] Comparative Examples 1 to 6

[0119] Comparative Examples 1 to 6 respectively provide a polyester elastomer, wherein the polyester elastomer comprises isocyanate, ether-containing compound, chain extender, crosslinking agent, end-capping agent and catalyst in parts by mass as shown in Table 1. The specific compounds of isocyanate, ether-containing compound, chain extender, crosslinking agent, end-capping agent and catalyst in the raw material of the anti-fatigue polyester elastomer are shown in Table 2.

[0120] The preparation methods of the polyester elastomers in Comparative Examples 1 to 6 are substantially the same as the preparation process of the fatigue-resistant polyester elastomer in Example 1, except that:

[0121] 1. In the prepolymerization process of step S1 of the polyester elastomer preparation process of Comparative Examples 1 to Comparative Examples 6, the stirring time and stirring temperature of the polyol and isocyanate before adding the catalyst, the reaction time and reaction temperature after adding the catalyst, and the cooling temperature after the reaction are shown in Table 3.

[0122] 2. In the preparation process of polyester elastomers of Comparative Examples 1 to 6, the reaction time and reaction temperature after adding the chain extender and the crosslinking agent in step S2 chain extension treatment are shown in Table 3.

[0123] 3. In the preparation process of polyester elastomers of Comparative Examples 1 to 6, the reaction time and reaction temperature after adding the end-capping agent in step S3 end-capping treatment are shown in Table 3.

[0124] Table 1

[0125]

[0126] In Examples 1 to 18 and Comparative Examples 1 to 6, the specific compounds of isocyanate, ether-containing compound, chain extender, cross-linking agent, end-capping agent and catalyst are shown in Table 2.

[0127] Table 2

[0128]

[0129]

[0130]

[0131] The chemical reagents in Table 2 were all purchased from commercial sources.

[0132] In Examples 1 to 18 and Comparative Examples 1 to 6,

[0133]

[0134] Finished product testing

[0135] The fatigue-resistant polyurethane elastomers of Examples 1 to 18 and the polyurethane elastomers of Comparative Examples 1 to 6 were taken to measure the fluorine content (wt%), the ratio of ether bonds to carbon-fluorine bonds, and the branch ratio, and the results are shown in Table 4. The carbon-fluorine bond and ether bond contents were measured by inductively coupled plasma-mass spectrometry (ICP-MS) and Fourier transform infrared spectrometer (FTIR), and the branch content was measured by gel chromatography (GPC). The mass in the branch ratio in Table 4 refers to the branch with an atomic number greater than or equal to 4, and the fluorine content (wt%) was measured by ICP-MS test.

[0136] Table 4

[0137] Fluorine content (wt%) Ether bond, carbon-fluorine bond ratio Branching ratio (%) Example 1 0.7 12 0.5 Example 2 0.6 14 1 Example 3 1.2 7 0.7 Example 4 0.3 32 0.9 Example 5 0.6 15 1.2 Example 6 0.6 12 1.1 Example 7 0.3 34 1 Example 8 0.8 8 0.6 Example 9 0.2 43 1.3 Example 10 0.2 43 1.5 Embodiment 11 0.9 10 1.1 Example 12 0.2 41 1.2 Example 13 0.4 32 1.4 Embodiment 14 0.4 21 1.2 Embodiment 15 0.2 41 0.6 Example 16 0.4 23 0.7 Embodiment 17 0.8 25 1.1 Embodiment 18 0.7 27 1.3 Comparative Example 1 / / 0.3 Comparative Example 2 / / 0.7 Comparative Example 3 / / / Comparative Example 4 / / / Comparative Example 5 / / 0.7 Comparative Example 6 / / /

[0138] Performance Testing

[0139] The fatigue-resistant polyurethane elastomers of Examples 1 to 18, the polyurethane elastomers of Comparative Examples 1 to 6, and the polyurethane elastomers of Covestro 392, Covestro 3059D, Covestro 3055D, Covestro 481, Covestro 445, Covestro 5377A and Covestro 588E were prepared into dumbbell-shaped specimens by injection molding, and the tensile strength, elongation at break, and 100% strain modulus of the elastomer were measured; strip samples were prepared to test wear resistance, right-angle specimens were prepared to test tear strength, and cylindrical samples were prepared to test compression performance, and the test results are shown in Table 5. The test standards for tensile strength, elongation at break, and 100% strain modulus are DIN 53504S1, and the test rate is 200 mm / min. The test standard for wear resistance adopts ASTM D5963; the test standard for tear strength adopts GB / T529-2008, and the test rate is 500mm / min; the test standard for compression times adopts ASTM D575; and the test standard for hardness adopts ASTM D2240.

[0140] The above-mentioned fatigue-resistant polyurethane elastomer, the comparative polyurethane elastomer and the commercially available polyurethane elastomer were prepared into dumbbell-shaped specimens by injection molding. After aging for 1000 hours at 85°C and 85% humidity, the tensile strength, elongation at break, 100% modulus, wear resistance, tear strength and compression times were measured again in the same manner. The results are shown in Table 6.

[0141] Table 5

[0142]

[0143]

[0144] Table 6

[0145]

[0146] As shown in Table 4, the fatigue-resistant polyurethane elastomer provided in the embodiment of the present application contains short polyester branches on the main chain, has a large melt index, is conducive to the processing of the material, and has a low branch content, so that the fatigue-resistant polyurethane elastomer has good folding and bending resistance.

[0147] As shown in Table 5, the fatigue-resistant polyurethane elastomers in Examples 1-18 have a hardness of ≥90 Shore A, a tensile strength of ≥55 MPa, a 100% modulus of ≥12 MPa, and a wear resistance of ≤30 mm. 3 ; The polyurethane elastomer in the comparative example has worse properties than those in Examples 1-18. Compared with the commercially available Covestro polyurethane, the fatigue-resistant polyurethane elastomer in Examples 1-18 has better tear resistance, tensile strength, 100% strain modulus, and wear resistance. The fatigue-resistant polyurethane elastomer of the present application has a higher 100% strain modulus, indicating that the bellows and other products using fatigue-resistant polyurethane elastomers have better deformation resistance than commercially available brands, and under the same deformation, the material has a greater load; the wear resistance and tear resistance of the fatigue-resistant polyurethane elastomer of the present application are better than those of commercially available brands, indicating that the material is more adaptable to the external environment under the same working conditions and broadens the application field of the material. The tensile strength of the fatigue-resistant polyurethane elastomer of the present application is better than that of commercially available brands, indicating that the mechanical strength of the fatigue-resistant polyurethane elastomer of the present application is good. When the fatigue-resistant polyurethane elastomer is used in products such as folding soft muscles for robots, the folding soft muscles and other products have a greater load.

[0148] The fatigue-resistant polyurethane elastomer provided in the embodiment of the present application effectively regulates the fluorine content, the ratio of ether bonds to carbon-fluorine bonds and the branching ratio in the fatigue-resistant polyurethane elastomer by regulating the mass fraction of ether compounds, isocyanates, chain extenders, crosslinking agents and end-capping agents and the compounds, and by regulating the polymerization steps. As a result, the tensile strength, elongation at break, 100% strain modulus, wear resistance, tear strength and compression times of the fatigue-resistant polyurethane elastomer are significantly increased without significantly changing the hardness.

[0149] As shown in Table 6, after the fatigue-resistant polyurethane elastomers in Examples 1-18 were placed in an oven at 85°C and 85% humidity for 1000 hours, the hardness change was ≤1 Shore A, and the tensile strength, 100% modulus, abrasion resistance and other properties were all less than 5%. Compared with the commercially available polyurethane elastomers and the polyurethane elastomers of the comparative examples, the fatigue-resistant polyurethane elastomers in Examples 1-16 of the present application have better aging resistance, and the material performance degradation after aging is lower.

[0150] The above embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the present application. It should be pointed out that, for a person of ordinary skill in the art, several modifications and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the attached claims.

Claims

1. A fatigue-resistant polyurethane elastomer, characterized in that: The raw material components include the following parts by weight: 40-70 parts of isocyanate; Contains 40-70 parts of ether compounds; Chain extender 4.7-25 parts; 0.4-3.5 parts of cross-linking agent; 0.5-5 parts of end-capping agent; 0.1-1.5 parts of catalyst; Wherein, the end-capping agent includes a fluorine-containing end-capping agent; The fatigue-resistant polyurethane elastomer contains 0.2-1.5 wt % of fluorine.

2. The fatigue-resistant polyurethane elastomer according to claim 1, characterized in that: The fatigue-resistant polyurethane elastomer comprises the following raw material components in parts by mass: 40-50 parts of isocyanate; Contains 40-50 parts of ether compounds; Chain extender 4.7-10 parts; Cross-linking agent 0.2-1 part; 0.5-3 parts of end-capping agent; 0.2 to 1 part of catalyst.

3. The fatigue-resistant polyurethane elastomer according to claim 1, characterized in that: The ratio of ether bonds to carbon-fluorine bonds in the fatigue-resistant polyurethane elastomer is 7:1 to 43:1; and / or The content of the branched chains in the fatigue-resistant polyurethane elastomer is 0.5-3%.

4. The fatigue-resistant polyurethane elastomer according to claim 3, characterized in that: The content of branched chains in the polyurethane elastomer is 0.5-1.5%.

5. The fatigue-resistant polyurethane elastomer according to any one of claims 1 to 4, characterized in that: The isocyanate comprises at least one of aromatic polyisocyanate, aliphatic polyisocyanate and alicyclic polyisocyanate; and / or The catalyst comprises at least one of dimethylethanolamine, triethylamine, triethylenediamine, dimethylaminoethyl ether, methyldiethanolamine, dimethylaminoethoxyethanol, N,N-dimethylbenzylamine, 1,2-dimethylimidazole, tetramethylethylenediamine, N,N-diethylethanolamine, tetramethyldipropylenetriamine, trimethylhydroxyethylpropylenediamine, bis(dimethylaminopropyl)isopropanolamine, N-(dimethylaminopropyl)diisopropanolamine, and dimethylaminoethoxyethanol; and / or The number of carbon atoms in the main chain of the chain extender is greater than or equal to 5; and / or The cross-linking agent includes at least one of polycaprolactone triol, galactitol, 1,2,6-hexanetriol, 1,2,3-butanetriol, 1,2,7-heptanetriol, 1,2,5-pentanetriol, 1,2,9-nonanetriol, 1,2,8-octantriol, 1,2,10-decanetriol, dipentaerythritol, tetrabromopentaerythritol, benzene-1,2,4,5-tetrol, tripentaerythritol, diethylenetriamine, pentamethyldipropylenetriamine, triethylenetetramine, and tribromide cyclohexanetetramine; and / or The end-capping agent includes at least one of fluorinated isocyanates, fluorinated alcohol compounds, fluorinated phenol compounds, fluorinated amine compounds, fluorinated carboxylic acid compounds, fluorinated aldehyde compounds, and fluorinated ester compounds.

6. The fatigue-resistant polyurethane elastomer according to claim 5, characterized in that: The chain extender includes at least one of 1,2-cyclopentanediol, 1,3-cyclopentanediol, 1,2-cyclohexanediol, 1,3-cyclohexanediol, 1,4-cyclohexanediol, 1,2-pentanediol, 1,4-pentanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, dipropylene glycol, diethylene glycol, triethylene glycol, tripropylene glycol, pentanediol, diethylene glycol, trimethylolpropane, and sorbitol; and / or The fluorinated isocyanates include 2-fluorophenyl isocyanate, 2-fluoro-5-methylphenyl isocyanate, 3-(trifluoromethyl)phenyl isocyanate, 2-p-fluoroisocyanate, trifluoroacetyl isocyanate, 2-(trifluoromethoxy)phenyl isocyanate, 4-bromo-2,6-difluorophenyl isocyanate, 2-(difluoromethoxy)phenyl isocyanate, 4-fluorophenylethyl isocyanate, 3,5-difluorophenyl isocyanate, 2,6-difluorophenyl isocyanate, 3-fluorophenylthioisocyanate, 2-fluorophenylethyl isocyanate, 2,4-difluorophenyl isocyanate, 2-(trifluoromethyl)phenyl isocyanate, 4-fluoro-2-nitrophenyl isocyanate, 4-fluorophenyl isocyanate, 3-chloro-4-fluorophenyl isocyanate, 2,3,5,6-tetrafluorophenylthio isocyanate, 2-methyl-3-fluorophenyl isocyanate, 4-fluoro-3-methylphenyl isocyanate, trifluoromethoxyphenyl isocyanate, 4-bromo-2-fluorophenyl isocyanate, 4-fluoro-3-nitrophenyl isocyanate, pentafluorophenyl thioisocyanate, 2,3,4-trifluorophenyl thioisocyanate, 3-fluoro-4-methylphenyl isocyanate, 2,5-difluorophenyl isocyanate, 5-fluoro-2-methylphenyl isocyanate, dicyclohexylmethane 4,4'-diisocyanate, 1,6-hexamethylene diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, 4-fluorobenzenesulfonyl isocyanate, trichloroacetyl isocyanate, octadecyl isocyanate, m-toluene isocyanate, m-chlorophenyl isocyanate, o-chlorophenyl isocyanate; and / or The fluorine-containing alcohol compound includes at least one of boron trifluoride isopropanol, 1,1,1,3,3,3-hexafluoro-2-propanol, 2-vinyl hexafluoroisopropanol, 2-(4-amino-3-methylphenyl)perfluoroisopropanol, 1,1,1-trifluoro-2-propanol, 4-fluoro-3-(trifluoromethyl)benzyl alcohol, perfluorobutanol, 4-fluorobenzyl alcohol, haloperidol, 2-fluoroethanol, and hexafluorobutanol; and / or The fluorine-containing phenol compound includes at least one of 2-fluoro-5-(trifluoromethyl)phenol, 3-fluoro-4-(trifluoromethoxy)phenol, 5-fluorothiophenol, 4-fluorophenol, 2,3,5,6-tetrafluoro-4-(trifluoromethyl)phenol, 3-fluorothiophenol, 2,3,5,6-tetrafluoro-4-(trifluoromethyl)thiophenol, 3-fluorophenol, 2-fluorophenol, pentafluorothiophenol, 2-fluorophenol, 5-fluorophenol, 4-fluorocatechol, and 3-fluorocatechol; and / or The fluorine-containing amine compound includes at least one of 2-fluoro-5-trifluoromethylpropylamine, 3-fluoro-5-trifluoromethylaniline, 2-fluoro-6-trifluoromethylaniline, 4-amino-2-trifluorotoluene, 4-fluoro-3-trifluoromethylaniline, 2-fluoro-3 (trifluoromethyl) aniline, 4-fluoro-2-(trifluoromethyl) benzylamine, 2,5-difluoro-4-(trifluoromethyl) aniline, 2-fluoro-3-(trifluoromethyl) benzylamine, 1-fluoroamine, m-fluorophenylethylamine, o-fluoroaniline, 3-fluoroaniline, 2,3,5,6-tetrafluoro-4-trifluoromethylaniline, o-fluorophenylethylamine, 4-fluorobenzylamine, 3-fluorobenzylamine, 2-fluorobenzylamine, 4-fluoroacetanilide, 4-bromo-2-fluoro-5-(trifluoromethyl) aniline, 2-fluoroamide, and 4-fluorobenzamide; and / or The fluorine-containing carboxylic acid compounds include 4-fluoro-2,3-fluoromethylpropylamine, fluoroboric acid, fluorosilicic acid, 2-fluoro-4-trifluoromethylbenzoic acid, 5-fluoro-2-(trifluoromethyl)benzoic acid, 2-fluoro-6-(trifluoromethyl)phenylacetic acid, trifluoroacetyl trifluoromethanesulfonate, p-fluorophenylacetic acid, 3-fluorobenzoic acid, 4-fluorocinnamic acid, 2-fluorobenzoic acid, o-fluorophenylacetic acid, 3-fluorophenylacetic acid, 3-fluoro-4-trifluoromethylbenzoic acid, 3-fluoro-5-(trifluoromethyl)benzoic acid, tetrafluoroterephthalic acid, perfluorooctanoic acid, 5-fluorosalicylic acid, 2-fluoro -4-(trifluoromethyl)pyridine-3-carboxylic acid, pentafluoropropionic acid, heptafluorobutyric acid, hexafluorophosphoric acid, pentafluorobenzoic acid, 4-fluorosalicylic acid, 3-fluorosalicylic acid, perfluorohexanoic acid, perfluorodecanoic acid, 4-fluoroanthranilic acid, tetrafluorosuccinic acid, heptadecafluorononanoic acid, 3-fluorophenylboric acid, heptafluorobutyric acid, p-fluorobenzoic acid, 2-fluoro-6-(trifluoromethyl)benzoic acid, nonafluoropentanoic acid, 2-fluorocinnamic acid, 3,3,3-trifluoro-2-hydroxy-2-(trifluoromethyl)propionic acid, tridecafluoroheptanoic acid, octafluoroadipic acid, p-fluorobenzoic acid at least one; and / or The fluorine-containing aldehyde compound includes at least one of 4-fluoro-2-trifluoromethylbenzaldehyde, 4-fluoro-3-trifluoromethylbenzaldehyde, 5-fluorosalicylaldehyde and 4-fluoro-2-formaldehyde pyridine; and / or The fluorine-containing ester compound includes at least one of tetramethylfluorouronium hexafluorophosphate, ethyl fluoroacetate, ethyl difluoroacetate, ethyl bromofluoroacetate, ethyl difluorobromoacetate, ethyl difluorochloroacetate, ethyl fluoroiodoacetate, ethyl fluoroiodoacetate, methyl 2-fluoronicotinate, and ethyl p-fluorobenzoate.

7. A method for preparing a fatigue-resistant polyurethane elastomer, characterized in that: The steps include: Prepolymerizing the ether-containing compound and isocyanate, or prepolymerizing the ether-containing compound, isocyanate and a catalyst to obtain a first prepolymer; The first prepolymer is subjected to a chain extension treatment with a chain extender and a cross-linking agent to obtain a second prepolymer; The second prepolymer is subjected to end-capping treatment with an end-capping agent to obtain a fatigue-resistant polyurethane elastomer; The mass fraction of the isocyanate is 40 to 70 parts, the mass fraction of the ether-containing compound is 40 to 70 parts, the mass fraction of the chain extender is 4.7 to 25 parts, the mass fraction of the cross-linking agent is 0.4 to 3.5 parts, the mass fraction of the end-capping agent is 0.5 to 5 parts, and the mass fraction of the catalyst is 0.1 to 1.5 parts; The fatigue-resistant polyurethane elastomer contains 0.2-1.5 wt % of fluorine.

8. The preparation method according to claim 7, characterized in that: The prepolymerization process comprises the following steps: subjecting the ether-containing compound and the isocyanate to a first prepolymerization treatment to obtain a preliminary reaction system; Performing a second prepolymerization treatment on the catalyst and the preliminary reaction system to obtain the first prepolymer; Wherein, the first prepolymerization process satisfies any one of the following conditions (1) to (2): (1) The temperature is 60-90°C, (2) Duration: 0.5 to 1 hour; The second prepolymerization process satisfies any one of the following conditions (3) to (4): (3) The temperature is 70-100°C, (4) The duration is 3 to 6 hours.

9. The preparation method according to any one of claims 7 to 8, characterized in that: The chain extension treatment is any one of the following conditions (1) to (2): (1) The temperature is 80-95°C, (2) Duration: 3 to 12 hours; and / or The end-capping treatment is any one of the following conditions (3) to (4): (3) The temperature is 60-90°C, (4) The duration is 2 to 10 hours.

10. Application of the fatigue-resistant polyurethane elastomer according to any one of claims 1 to 6 or the fatigue-resistant polyurethane elastomer prepared by the method for preparing the fatigue-resistant polyurethane elastomer according to any one of claims 7 to 9 in folding soft muscles, automobile tires, sports pulley equipment, wind turbine shock absorption, large water storage tanks, and photovoltaic module protective films.

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