Semi-prefabricated high-weather-resistance high-temperature-resistant polyurethane elastomer and preparation method thereof

Abstract

The invention provides a semi-prefabricated high-weather-resistance high-temperature-resistant polyurethane elastomer and a preparation method thereof. The raw material formula of the semi-prefabricated high-weather-resistance high-temperature-resistant polyurethane elastomer is prepared from the following components: 75 to 90 parts of isocyanate prepolymer, 10 to 15 parts of chain extender and 0.1 to 1 part of antioxidant, the isocyanate prepolymer comprises a prepolymer which is prepared by reacting hydroxyl-terminated silicone oil, sulfur-containing polyol and isocyanate; the weight ratio of the hydroxyl-terminated silicone oil to the sulfur-containing polyol is 1: (1-2). The semi-prefabricated high-weather-resistance high-temperature-resistant polyurethane elastomer prepared by the invention has excellent mechanical properties, and still has good tensile strength under the conditions of high temperature, ultraviolet irradiation and saline water.

Description

Technical Field

[0001] The present invention relates to the technical field of polyurethane elastomers, and particularly relates to a semi-preformed high weather resistance and high temperature resistant polyurethane elastomer and a preparation method thereof. Background Art

[0002] Polyurethane elastomer, also known as polyurethane rubber, is a kind of polymer with many repeating units, and there are many urethane groups on its main chain. It is produced by stepwise polymerization through the reaction of isocyanate with alcohol or amine. In addition to urethane groups, other groups are often generated, so the structure of polyurethane is complex, with various forms and different properties.

[0003] The heat resistance temperature range of polyurethane is generally from -20°C to 120°C. However, in actual use, the long-term use temperature of polyurethane is generally below 80°C, and the short-term use temperature cannot exceed 120°C. There are few polyurethane products that can be used long-term under the conditions of 100 - 120°C, which makes polyurethane greatly affected by the environment during use, especially in harsh environments such as high temperature and high humidity.

[0004] Traditional polyether polyols often have the disadvantages of low strength and poor weather resistance when preparing polyurethane elastomers; ordinary polyester polyols have the disadvantage of poor hydrolysis resistance when preparing polyurethane elastomers.

[0005] Therefore, developing a polyurethane elastomer that can maintain good mechanical properties in harsh environments such as high temperature and high humidity, and at the same time has excellent weather resistance and hydrolysis resistance has become the focus and difficulty of current research. This not only requires innovation in molecular structure design but also optimization in formulation composition and preparation process to comprehensively improve the performance of polyurethane elastomers. Summary of the Invention

[0006] Aiming at the problems of the existing technology, the present invention overcomes the deficiencies of the existing technology and provides a high weather resistance and high temperature resistant polyurethane elastomer with excellent mechanical properties of the product, which still has good tensile strength under high temperature, light, and brine conditions. At the same time, the present invention also provides a preparation method thereof.

[0007] On the one hand, the present invention provides a semi-preformed high weather resistance and high temperature resistant polyurethane elastomer, which is characterized in that its raw material formula consists of the following components: 75 - 90 parts of isocyanate prepolymer, 10 - 15 parts of chain extender, and 0.1 - 1 part of antioxidant; The isocyanate prepolymer includes a prepolymer prepared by the reaction of terminal hydroxyl silicone oil, sulfur-containing polyol and isocyanate; The weight ratio of the terminal hydroxyl silicone oil to the sulfur-containing polyol is 1:(1 - 2).

[0008] Preferably, the chain extender is selected from at least one of 1,4-butanediol (BDO), propylene glycol (PG), ethylene glycol (EG), 1,6-hexanediol (HDO), hydroquinone-bis(β-hydroxyethyl) ether (HQEE), diethyltoluenediamine (DETDA), dimethylthiotoluenediamine (DMTDA), 4,4'-methylenebis(3-chloro-2,6-diethylaniline) (MCDEA), or 3,3'-dichloro-4,4'-diaminodiphenylmethane (MOCA).

[0009] Preferably, the antioxidant is selected from at least one of 2,6-di-tert-butyl-4-methylphenol, tris(2,4-di-tert-butylphenyl) phosphite, antioxidant 1010, antioxidant 1035, antioxidant 1076, or antioxidant 1135.

[0010] Preferably, the isocyanate prepolymer, by weight, comprises 5-10 parts of hydroxyl-terminated silicone oil, 5-10 parts of sulfur-containing polyol, 100 parts of isocyanate, and 0.01-0.2 parts of catalyst.

[0011] Preferably, the hydroxyl value of the hydroxyl-terminated silicone oil is greater than or equal to 8%.

[0012] Preferably, the hydroxyl value of the hydroxyl-terminated silicone oil is 8-15%.

[0013] Preferably, the sulfur-containing polyol is prepared by subjecting eugenol, mercaptoalcohol compounds, and a photoinitiator to a thiol-ene click reaction to obtain the sulfur-containing polyol.

[0014] Preferably, the mercaptoalcohol compounds include any one or a combination of more than one of β-mercaptoethanol, 3-mercapto-1,2-propanediol, 1,4-dithiothreitol, or 1,4-dimercapto-2,3-butanediol.

[0015] Preferably, the photoinitiator is any one or a combination of more than one of 2-hydroxy-2-methyl-1-phenyl-1-propanone, 2,4,6-trimethylbenzoyl diphenylphosphine oxide, isopropylthioxanthone, or 2,4-diethylthiazolethione.

[0016] Preferably, the isocyanate is selected from at least one of toluene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), isophorone diisocyanate (IPDI), 4,4'-dicyclohexylmethane diisocyanate (HMDI), hexamethylene diisocyanate (HDI), p-phenylene diisocyanate (PPDI), or 1,5-naphthalene diisocyanate (NDI).

[0017] In a second aspect, the present application provides a method for preparing a semi-preformed high weather resistance and high temperature resistant polyurethane elastomer, comprising the following steps: Step 1: Taking parts by weight, 5 - 10 parts of hydroxyl-terminated silicone oil, 5 - 10 parts of sulfur-containing polyol, 100 parts of isocyanate, and 0.01 - 0.2 parts of catalyst are stirred under nitrogen protection at 60 - 80 °C for 1 - 3 h to obtain an isocyanate prepolymer; Step 2: Taking parts by weight, 75 - 90 parts of the isocyanate prepolymer obtained in Step 1 and 0.1 - 1 part of antioxidant are mixed and degassed under vacuum at room temperature for 0.5 - 2 h, then 2 - 50 parts of chain extender are added, and the mixture is stirred at 50 - 70 °C for 1 - 3 h to carry out crosslinking and curing reaction to obtain a semi-preformed high weather resistance and high temperature resistant polyurethane elastomer.

[0018] Preferably, the catalyst is selected from at least one of dibutyltin dilaurate, bismuth neodecanoate, or triethylenediamine.

[0019] The semi-preformed high weather resistance and high temperature resistant polyurethane elastomer provided by this application has the following functions: In the present invention, the isocyanate prepolymer prepared by adding hydroxyl-terminated silicone oil, sulfur-containing polyol, and isocyanate introduces siloxane segments and thioether segments into the polyurethane elastomer. By adjusting the component ratio, the microphase separation structure of the polyurethane is regulated. The thioether and siloxane segments are flexible segments.

[0020] The benzene rings introduced by the thioether and the benzene rings in the isocyanate, and the urethanes obtained from the crosslinking reaction of high hydrogen content hydroxyl-terminated silicone oil and isocyanate are hard segments. The microphase separation structure can improve the mechanical properties and high temperature resistance of the polyurethane. The thioether groups formed after crosslinking will form reversible dynamic bonds - disulfide bonds in the elastomer, release stress through bond recombination at high temperatures, and have self-healing ability at high temperatures to avoid embrittlement and cracking of the material; the shielding effect of sulfur atoms on ultraviolet rays can reduce photooxidative degradation. The siloxane segments introduced by the thioether have high heat resistance due to the high chemical bond energy of the silicon-oxygen bond.

[0021] The semi-preformed high weather resistance and high temperature resistant polyurethane elastomer of this application has a simple process flow and is easy to operate. It has a market promotion prospect. Specific Embodiments

[0022] In order to make the objectives, technical solutions, and advantages of the present invention clearer, the following further elaborates on the present invention with reference to embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0023] In order to illustrate the technical solution of the present invention, it is described below through specific embodiments.

[0024] In a first aspect, the present invention provides a semi-preformed high weather resistance and high temperature resistant polyurethane elastomer, which is characterized in that its raw material formula consists of the following components: 75-90 parts of isocyanate prepolymer, such as 75, 78, 80, 83, 85, 88, 90, etc., but not limited to the listed values, and the combinations not listed within this range are equally applicable; 10-15 parts of chain extender, such as 10, 11, 12, 13, 14, 15, etc., but not limited to the listed values, and the combinations not listed within this range are equally applicable; 0.1-1 part of antioxidant, such as 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, etc., but not limited to the listed values, and the combinations not listed within this range are equally applicable. The isocyanate prepolymer described above includes a prepolymer prepared by reacting a hydroxyl-terminated silicone oil and a sulfur-containing polyol with an isocyanate; The weight ratio of the hydroxyl-terminated silicone oil and the sulfur-containing polyol is 1:(1-2), such as 1:1, 1:1.1, 1:1.2, 1:1.3, 1:1.4, 1:1.5, 1:1.6, 1:1.7, 1:1.8, 1:1.9, 1:2, etc., but not limited to the listed values, and the combinations not listed within this range are equally applicable.

[0025] In this embodiment, a silicon chain segment of hydroxyl-terminated silicone oil is added. The Si-O bond has a higher bond energy, which can delay thermal degradation and improve the high temperature resistance of the polyurethane elastomer. The silicon-oxygen chain segment forms a soft segment micro-region in the polyurethane elastomer, improving the flexibility at high temperatures, but an excessive amount will lead to a decrease in compatibility with the polyurethane matrix, resulting in a sharp reduction in mechanical properties.

[0026] Adding sulfur-containing polyol to the polyurethane elastomer, sulfur-sulfur bonds or stable structures formed with isocyanates increase the crosslinking points and inhibit the movement of molecular chains, thereby improving the high temperature resistance; however, when the content of sulfur-containing polyol is too large, the molecular chain rigidity becomes too strong, reducing the toughness of the material. The thioether groups obtained after crosslinking will form reversible dynamic bonds - disulfide bonds in the elastomer, releasing stress through bond recombination at high temperatures, having self-healing ability at high temperatures, and avoiding embrittlement and cracking of the material; the shielding effect of sulfur atoms on ultraviolet rays can reduce photooxidative degradation.

[0027] In a high temperature environment, sulfur inhibits the movement of chain segments through crosslinking, and silicon delays decomposition through bond energy, synergistically enhancing the high temperature resistance. In a sodium chloride aqueous solution, sulfur constructs a dense crosslinked structure to reduce the diffusion channels of Cl⁻; silicon forms a hydrophobic layer on the surface, doubly blocking the intrusion of salt water. By controlling the amounts of hydroxyl-terminated silicone oil and sulfur-containing polyol, the optimal performance has been achieved.

[0028] In some embodiments, the chain extender is selected from at least one of 1,4-butanediol (BDO), propylene glycol (PG), ethylene glycol (EG), 1,6-hexanediol (HDO), hydroquinone bis(β-hydroxyethyl) ether (HQEE), diethyltoluenediamine (DETDA), dimethylthiotoluenediamine (DMTDA), 4,4'-methylenebis(3-chloro-2,6-diethylaniline) (MCDEA), or 3,3'-dichloro-4,4'-diaminodiphenylmethane (MOCA).

[0029] In a preferred embodiment, the chain extender is 1,4-butanediol (BDO).

[0030] In some embodiments, the antioxidant is selected from at least one of 2,6-di-tert-butyl-4-methylphenol, tris(2,4-di-tert-butylphenyl) phosphite, antioxidant 1010, antioxidant 1035, antioxidant 1076, or antioxidant 1135.

[0031] In a preferred embodiment, the antioxidant is 2,6-di-tert-butyl-4-methylphenol.

[0032] In some embodiments, the isocyanate prepolymer, by weight, comprises 5 to 10 parts of hydroxyl-terminated silicone oil, such as 5, 6, 7, 8, 9, 10, etc., but not limited to the listed values, and the combinations not listed within this range are also applicable; 5 to 10 parts of sulfur-containing polyol, such as 5, 6, 7, 8, 9, 10, etc., but not limited to the listed values, and the combinations not listed within this range are also applicable; 100 parts of isocyanate; 0.01 to 0.2 parts of catalyst, such as 0.01, 0.05, 0.1, 0.15, 0.2, etc., but not limited to the listed values, and the combinations not listed within this range are also applicable.

[0033] In some embodiments, the hydroxyl value of the hydroxyl-terminated silicone oil is greater than or equal to 8%, such as 8%, 8.5%, 9%, 9.5%, 10%, 10.5%, 11%, etc., but not limited to the listed values, and the combinations not listed within this range are also applicable.

[0034] In a preferred embodiment, the hydroxyl value of the hydroxyl-terminated silicone oil is 8 - 15%.

[0035] In some embodiments, the sulfur-containing polyol is prepared by subjecting eugenol, mercaptoalcohol compounds, and a photoinitiator to a thiol-ene click reaction to obtain the sulfur-containing polyol.

[0036] In some embodiments, the mercaptoalcohol compounds include any one or a combination of β-mercaptoethanol, 3-mercapto-1,2-propanediol, 1,4-dithiothreitol, or 1,4-dimercapto-2,3-butanediol.

[0037] In a preferred embodiment, the mercapto alcohol compound is β-mercaptoethanol.

[0038] In some embodiments, the photoinitiator is any one or a combination of more than one of 2-hydroxy-2-methyl-1-phenyl-1-propanone, 2,4,6-trimethylbenzoyl diphenylphosphine oxide, isopropylthioxanthone or 2,4-diethylthiazol-2(3H)-one.

[0039] In a preferred embodiment, the photoinitiator is any one of 2-hydroxy-2-methyl-1-phenyl-1-propanone or isopropylthioxanthone, wherein the isopropylthioxanthone is a mixture of 2,4-isomers of isopropylthioxanthone.

[0040] In some embodiments, the isocyanate is selected from at least one of toluene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), isophorone diisocyanate (IPDI), 4,4'-dicyclohexylmethane diisocyanate (HMDI), hexamethylene diisocyanate (HDI), p-phenylene diisocyanate (PPDI) or 1,5-naphthalene diisocyanate (NDI).

[0041] In a preferred embodiment, the isocyanate is diphenylmethane diisocyanate (MDI).

[0042] In a second aspect, the present application provides a method for preparing a semi-preformed high weather resistance and high temperature resistant polyurethane elastomer, comprising the following steps: Step 1: By weight, 5-10 parts of hydroxyl-terminated silicone oil, 5-10 parts of sulfur-containing polyol, 100 parts of isocyanate and 0.01-0.2 parts of catalyst are stirred at 60-80 °C for 1-3 h under nitrogen protection to obtain an isocyanate prepolymer; Step 2: By weight, 75-90 parts of the isocyanate prepolymer obtained in Step 1 and 0.1-1 part of antioxidant are mixed and degassed under vacuum at room temperature for 0.5-2 h, 2-50 parts of chain extender are added, and the mixture is stirred at 50-70 °C for 1-3 h for crosslinking and curing reaction to obtain a semi-preformed high weather resistance and high temperature resistant polyurethane elastomer.

[0043] Preferably, the catalyst is selected from at least one of dibutyltin dilaurate, bismuth neodecanoate or triethylenediamine.

[0044] In a preferred embodiment, the catalyst is dibutyltin dilaurate.

[0045] The present invention will be further described below through preparation examples and implementation examples.

[0046] Preparation Examples Under an inert gas atmosphere and ultraviolet light conditions, 100 g of eugenol (grade E809010, purchased from Macklin), 47.5 g of β-mercaptoethanol (grade M6230, purchased from Macklin), and 2-hydroxy-2-methyl-1-phenyl-1-propanone (2.0 wt%) (purchased from Guangzhou Yuanda New Materials Co., Ltd.) were subjected to a thiol-ene click reaction in a reaction kettle for 4 h to obtain a sulfur-containing polyol. Example 1

[0047] The present invention provides a method for preparing a semi-preformed high weather resistance and high temperature resistant polyurethane elastomer. Step 1: By weight, 7 parts of hydroxyl-terminated silicone oil (grade XSC-P1503, hydroxyl value 8-10%, purchased from Zhejiang Xinshichen New Materials Co., Ltd.), 7 parts of sulfur-containing polyol, 100 parts of diphenylmethane diisocyanate (MDI) (grade XSC-P1503, purchased from Yantai Wanhua Polyurethane Co., Ltd.), and 0.01 part of dibutyltin dilaurate (grade KR-90, purchased from Changzhou Kerry Chemical Technology Co., Ltd.) were stirred at 80 °C for 3 h under nitrogen protection to obtain an isocyanate prepolymer. Step 2: By weight, 80 parts of the isocyanate prepolymer obtained in Step 1 and 0.5 part of 2,6-di-tert-butyl-4-methylphenol (purchased from Shanghai Feige Chemical Co., Ltd.) were mixed and degassed under vacuum at room temperature for 1 h, then 13 parts of 1,4-butanediol (BDO) (purchased from Jinan Dezheng Chemical Co., Ltd.) were added, and the mixture was stirred at 60 °C for 2 h to carry out a crosslinking and curing reaction to obtain a semi-preformed high weather resistance and high temperature resistant polyurethane elastomer. Example 2

[0048] Most of the steps in this example are the same as those in Example 1. The difference is that in Step 1, 5 parts of hydroxyl-terminated silicone oil and 5 parts of sulfur-containing polyol were added. Example 3

[0049] Most of the steps in this example are the same as those in Example 1. The difference is that in Step 1, 10 parts of hydroxyl-terminated silicone oil and 10 parts of sulfur-containing polyol were added. Example 4

[0050] Most of the steps in this example are the same as those in Example 1. The difference is that in Step 1, 5 parts of hydroxyl-terminated silicone oil and 7 parts of sulfur-containing polyol were added. Example 5

[0051] Most of the steps in this example are the same as those in Example 1. The difference is that in Step 1, 5 parts of hydroxyl-terminated silicone oil and 10 parts of sulfur-containing polyol were added. Example 6

[0052] Most steps of this embodiment are the same as those of Embodiment 1, and the difference is that: 75 parts of isocyanate prepolymer are added in Step 2. Example 7

[0053] Most steps of this embodiment are the same as those of Embodiment 1, and the difference is that: 85 parts of isocyanate prepolymer are added in Step 2. Example 8

[0054] Most steps of this embodiment are the same as those of Embodiment 1, and the difference is that: 95 parts of isocyanate prepolymer are added in Step 2.

[0055] Comparative Example 1 Most steps of this comparative example are the same as those of Embodiment 1, and the difference is that: no terminal hydroxyl silicone oil is added in Step 1.

[0056] Comparative Example 2 Most steps of this comparative example are the same as those of Embodiment 1, and the difference is that: no sulfur-containing polyol is added in Step 1.

[0057] Comparative Example 3 Most steps of this comparative example are the same as those of Embodiment 1, and the difference is that: 5 parts of terminal hydroxyl silicone oil and 15 parts of sulfur-containing polyol are added in Step 1.

[0058] Comparative Example 4 Most steps of this comparative example are the same as those of Embodiment 1, and the difference is that: 15 parts of terminal hydroxyl silicone oil and 7 parts of sulfur-containing polyol are added in Step 1.

[0059] Comparative Example 5 Most steps of this comparative example are the same as those of Embodiment 1, and the difference is that: 7 parts of terminal hydroxyl silicone oil (grade XSC-P1503, hydroxyl value 3.6 - 4%, purchased from Zhejiang Xinshichen New Materials Co., Ltd.) are added in Step 1.

[0060] Performance Test The semi-preformed high weather resistance and high temperature resistant polyurethane elastomers prepared in the above examples and comparative examples are subjected to the following tests.

[0061] The tensile strength is carried out according to the requirements of standard GB / T 528 - 2009. Before testing, the specimens are first conditioned in a temperature and humidity environment of 25 ± 2°C and 50 ± 5% RH for 24 h and then tested. In the aging test, the specimens are placed in different aging environments. After the aging is completed, the tensile strength and elongation at break of the specimens are tested again. The weather resistance of the specimens is comprehensively evaluated through the results of heat aging and artificial weather aging, and the hydrolysis resistance of the specimens is evaluated through the results after immersion aging. Heat aging is to place the specimens under high temperature conditions of 140 °C for 28 days of heat aging. After the aging is completed, environmental conditioning is carried out in accordance with the provisions of GB / T 2941-2006, and then the tensile strength is tested in accordance with the requirements of national standard GB / T 528-2009. The heat aging resistance of the elastomer specimens is characterized by the change in tensile strength.

[0062] The test conditions for ultraviolet aging resistance are carried out in accordance with the requirements of standard GB / T 16585-1996. Specifically, a UVA ultraviolet light source is used to carry out cyclic aging of irradiating the specimens for 4 h followed by condensation for 4 h for 28 days. After the aging is completed, state adjustment is carried out in accordance with the provisions of GB / T 2941-2006, and then the tensile strength is tested in accordance with the requirements of standard GB / T 528-2009. The ultraviolet aging resistance of the polyurethane elastomer specimens is characterized by the change in tensile strength.

[0063] Brine aging is to soak the specimens in a 5% sodium chloride aqueous solution at 40 °C for 28 days for hydrolysis aging. After the aging is completed, environmental conditioning is carried out in accordance with the provisions of GB / T 2941-2006, and then the tensile strength is tested in accordance with the requirements of standard GB / T 528-2009. The hydrolysis resistance of the polyurethane elastomer specimens is characterized by the change in tensile strength.

[0064] The above test results are shown in Table 1.

[0065] Table 1 Group Initial Tensile Strength (MPa) Tensile Strength after Thermal Aging (MPa) Tensile Strength after UV Aging (MPa) Tensile Strength after Salt Water Aging (MPa) Example 1 25.31 20.45 21.16 23.58 Example 2 19.75 14.05 15.79 14.79 Example 3 20.77 15.57 17.67 19.57 Example 4 22.98 18.11 19.64 15.47 Example 5 21.32 14.67 17.57 19.16 Example 6 24.05 18.67 20.35 22.47 Example 7 25.45 20.67 21.21 23.44 Example 8 25.33 20.77 21.32 23.69 Comparative Example 1 17.30 10.13 6.33 9.56 Comparative Example 2 15.48 5.98 12.66 6.59 Comparative Example 3 18.56 13.00 14.39 16.78 Comparative Example 4 14.55 12.96 10.84 11.79 Comparative Example 5 14.21 11.56 13.56 12.44 Combining Comparative Example 1 and Comparative Example 1, it can be seen that adding terminal hydroxyl silicone oil mainly affects the mechanical properties of the polyurethane elastomer, and has a greater impact on high-temperature aging and brine aging; combining Comparative Example 1 and Comparative Example 2, it can be seen that adding sulfur-containing polyols mainly has a greater impact on the ultraviolet aging resistance of the polyurethane elastomer; in Comparative Example 1, due to the synergistic effect, a polyurethane elastomer with the best performance was prepared, with an initial tensile strength of 25.31 MPa, a tensile strength after heat aging of 20.45 MPa, a tensile strength after ultraviolet aging of 21.16 MPa, and a tensile strength after brine aging of 23.58 MPa.

[0066] As can be seen from Examples 1-3, when the mass ratio of the added terminal hydroxyl silicone oil and sulfur-containing polyol is 1:1, due to the formation of a similar microphase separation structure, when increasing and decreasing in equal ratio, the performance increases and decreases with the change of the addition amount. As can be seen from Examples 2, 4, 5 and Comparative Example 3, when the terminal hydroxyl silicone oil remains unchanged and the amount of sulfur-containing polyol is increased, the tensile strength of ultraviolet aging shows a trend of first increasing and then decreasing. When 15 parts of sulfur-containing polyol are added, the tensile strength of ultraviolet aging drops to 14.39 MPa, and the tensile strength of heat aging is 13.00 MPa. From Comparative Example 4, it can be seen that when 15 parts of terminal hydroxyl silicone oil are added, since the proportion of the siloxane segment is relatively high and the proportion of the soft segment is relatively high, the initial tensile strength will decrease sharply, making it not suitable for industrial applications.

[0067] As can be seen from Examples 1 and 6-8, the reaction of the isocyanate prepolymer with the chain extender will affect the formation of the hard segment of the polyurethane elastomer. For example, compared with Example 1 in Example 6, since less isocyanate prepolymer is added, it will lead to a decrease in the content of the cyanate hard segment and relatively poor mechanical properties; compared with Example 1 in Examples 7 and 8, even if the amount of the added isocyanate prepolymer is increased further, the performance will not increase significantly anymore.

[0068] As can be seen from Example 1 and Comparative Example 5, adding terminal hydroxyl silicone oil with a low hydroxyl value will reduce the crosslinking points and the proportion of the hard segment, resulting in a decrease in the initial tensile strength; the degree of crosslinking decreases, and the aging resistance and salt water aging resistance decrease.

[0069] The above examples are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing examples, those of ordinary skill in the art should understand that: they can still modify the technical solutions recorded in the foregoing examples, or perform equivalent replacements for some of the technical features. And these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be included in the protection scope of the present invention.

Claims

1. A semi-preformed high weather resistance and high temperature resistant polyurethane elastomer, characterized in that, Its raw material formula consists of the following components: 75 - 90 parts of isocyanate prepolymer, 10 - 15 parts of chain extender, and 0.1 - 1 part of antioxidant; The isocyanate prepolymer mentioned above is a prepolymer prepared by reacting hydroxyl-terminated silicone oil, sulfur-containing polyol with isocyanate; The weight ratio of the hydroxyl-terminated silicone oil to the sulfur-containing polyol is 1:(1 - 2).

2. The semi-preformed high weather resistance and high temperature resistance polyurethane elastomer according to claim 1, characterized in that, The chain extender selected from at least one of 1,4-butanediol, propylene glycol, ethylene glycol, 1,6-hexanediol, hydroquinone-bis(β-hydroxyethyl) ether, diethyltoluenediamine, dimethylthiotoluenediamine, 4,4'-methylenebis(3-chloro-2,6-diethylaniline) or 3,3'-dichloro-4,4'-diaminodiphenylmethane.

3. The semi-preformed high weather resistance and high temperature resistance polyurethane elastomer according to claim 1, characterized in that The antioxidant selected from at least one of 2,6-di-tert-butyl-4-methylphenol, tris(2,4-di-tert-butylphenyl) phosphite, antioxidant 1010, antioxidant 1035, antioxidant 1076 or antioxidant 1135.

4. The semi-preformed high weather resistance and high temperature resistance polyurethane elastomer according to claim 1, characterized in that, The isocyanate prepolymer, by weight, contains 5 - 10 parts of hydroxyl-terminated silicone oil, 5 - 10 parts of sulfur-containing polyol, 100 parts of isocyanate, and 0.01 - 0.2 part of catalyst.

5. The semi-preformed high weather resistance and high temperature resistance polyurethane elastomer according to claim 4, characterized in that, The hydroxyl value of the hydroxyl-terminated silicone oil is greater than or equal to 8%.

6. The semi-preformed high weather resistance and high temperature resistance polyurethane elastomer according to claim 5, characterized in that, The hydroxyl value of the hydroxyl-terminated silicone oil is 8 - 15%.

7. The semi-preformed high weather resistance and high temperature resistance polyurethane elastomer according to claim 1, characterized in that, The sulfur-containing polyol is prepared by thiol-ene click reaction of eugenol, mercapto alcohol compounds and photoinitiator to obtain sulfur-containing polyol.

8. The semi-preformed high weather resistance and high temperature resistance polyurethane elastomer according to claim 1, characterized in that, The isocyanate selected from at least one of toluene diisocyanate, diphenylmethane diisocyanate, isophorone diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, hexamethylene diisocyanate, p-phenylene diisocyanate or 1,5-naphthalene diisocyanate.

9. The preparation method of the semi-preformed high weather resistance and high temperature resistant polyurethane elastomer as described in claim 1, comprising the following steps: Step 1: By weight, pre-polymerize hydroxyl-terminated silicone oil, sulfur-containing polyol, isocyanate and catalyst to obtain isocyanate prepolymer; Step 2: By weight, mix the isocyanate prepolymer obtained in Step 1 with antioxidant, evacuate and defoam, then add chain extender, and carry out crosslinking and curing reaction under stirring conditions to obtain semi-preformed high weather resistance and high temperature resistant polyurethane elastomer.

10. The preparation method of the semi-preformed high weather resistance and high temperature resistant polyurethane elastomer according to claim 9, characterized in that, The catalyst selected from at least one of dibutyltin dilaurate, bismuth neodecanoate or triethylenediamine.