Polyurethane thermal insulation material for geothermal well oil pipe and preparation method of polyurethane thermal insulation material

Abstract

The invention belongs to the technical field of polyurethane heat insulation materials, and particularly relates to a polyurethane heat insulation material for geothermal well oil pipes and a preparation method of the polyurethane heat insulation material. According to the polyurethane heat insulation and heat preservation material for the geothermal well oil pipe, polyester polyol and polyether polyol are mixed and react with 4, 4 '-dicyclohexylmethane diisocyanate, the mechanical property of the prepared polyurethane material is fundamentally guaranteed, meanwhile, 2, 4-diamino-3, 5-dimethylthiotoluene and 1, 4-butane diamine are added, and the polyurethane heat insulation and heat preservation material for the geothermal well oil pipe has the advantages that the mechanical property of the polyurethane material is greatly improved; the modified palygorskite, the phenolic aldehyde hollow microspheres and the polyacrylonitrile pre-oxidized fibers are used as fillers to be added, so that the heat insulation performance of the prepared polyurethane material is ensured, and the raw materials have a synergistic effect, so that the heat insulation performance of the polyurethane material is improved, and the heat insulation performance of the polyurethane material is improved. The mechanical property and the thermal insulation property of the prepared polyurethane material are ensured.

Description

Technical Field

[0001] The invention belongs to the technical field of polyurethane heat insulation materials, and specifically relates to a polyurethane heat insulation material for geothermal well oil pipes and a preparation method thereof. Background Art

[0002] Geothermal well oil pipe is a pipe used in geothermal wells. Its main function is to transport underground hot water or geothermal steam from geothermal wells to the ground. Geothermal well oil pipe plays a vital role in the exploitation of geothermal energy. It not only needs to have good thermal insulation performance to reduce heat energy loss, but also needs to have sufficient strength to adapt to the high temperature and high pressure environment of geothermal wells. In view of the serious heat loss and poor insulation effect of ordinary oil pipes, using insulated oil pipes instead of ordinary oil pipes can greatly reduce steam heat loss.

[0003] Thermal insulation coatings are a type of material that achieves thermal insulation effects by using low thermal conductivity materials to block or weaken the heat transfer process. Thermal insulation coatings are divided into organic thermal insulation coatings, inorganic thermal insulation coatings, and organic-inorganic composite thermal insulation coatings. Organic thermal insulation coatings mainly include polyurethane foam, polystyrene foam, and polysiloxane porous coatings; inorganic thermal insulation coatings mainly include perlite foam materials and SiO2 aerogels; organic-inorganic composite thermal insulation coatings mainly include hollow glass microsphere composite thermal insulation coatings, hollow SiO2 microsphere composite thermal insulation coatings, and porous ceramic composite thermal insulation coatings. Compared with inorganic thermal insulation coatings and organic-inorganic composite thermal insulation coatings, organic thermal insulation coatings have lower thermal conductivity and better physical properties. Among organic thermal insulation coatings, polyurethane foam has become the most promising thermal insulation material due to its low cost, high mechanical strength, and low thermal conductivity. However, when the existing polyurethane foam is used for the insulation of geothermal well oil pipes, due to the high temperature and high pressure application environment, its mechanical properties, thermal insulation properties and temperature resistance are limited. Therefore, it is necessary to explore a new type of polyurethane thermal insulation material for geothermal well oil pipes. Summary of the invention

[0004] The purpose of the present invention is to provide a polyurethane heat insulation material for geothermal well oil pipes. The polyurethane heat insulation material has excellent mechanical properties and heat preservation properties; the present invention also provides a preparation method thereof.

[0005] The polyurethane thermal insulation material for geothermal well oil pipe of the present invention is composed of the following raw materials in parts by weight: 28-30 parts of bisphenol A polyether polyol, 15-17 parts of polycaprolactone diol, 32-34 parts of trimethylolpropane polyether polyol, 115.5-118.5 parts of 4,4'-dicyclohexylmethane diisocyanate, 2.8-3.0 parts of 2,4-diamino-3,5-dimethylthiotoluene, 3-3.3 parts of 1,4-butanediamine, 1.50-1.62 parts of pentamethyldiethylenetriamine, 5-5.4 parts of water, and 10 parts of a mixture of modified palygorskite, phenolic hollow microspheres and polyacrylonitrile pre-oxidized fibers. -12 parts; wherein, the preparation method of the mixture of modified palygorskite, phenolic hollow microspheres and polyacrylonitrile pre-oxidized fibers comprises the following steps: adding palygorskite, phenolic hollow microspheres and polyacrylonitrile pre-oxidized fibers to a mixed solution of γ-methacryloxypropyltrimethoxysilane and anhydrous ethanol, stirring at a speed of 400-420r / min for 48-50min, then filtering and washing with ethanol to remove residual γ-methacryloxypropyltrimethoxysilane, and finally drying at 75-78°C for 7h to prepare a mixture of modified palygorskite, phenolic hollow microspheres and polyacrylonitrile pre-oxidized fibers.

[0006] in: The mass ratio of the mixture of palygorskite, phenolic hollow microspheres and polyacrylonitrile pre-oxidized fibers to the volume ratio of the mixed solution of γ-methacryloxypropyltrimethoxysilane and anhydrous ethanol is 1:22, and the unit is g / mL.

[0007] The mass concentration of γ-methacryloxypropyltrimethoxysilane in the mixed solution of γ-methacryloxypropyltrimethoxysilane and anhydrous ethanol is 1.7%.

[0008] The mass ratio of palygorskite, phenolic hollow microspheres and polyacrylonitrile pre-oxidized fibers is 10-12: 2.3-3.4: 4.5-5.7.

[0009] The chemical composition of the palygorskite, in terms of mass percentage, is as follows: SiO2 58.10%, MgO 17.24%, Al2O3 11.15%, Fe2O3 1.52%, CaO 0.76%, K2O 0.15%, Na2O 0.15%, and loss on ignition 10.93%.

[0010] The functionality of bisphenol A polyether polyol is 2, and the hydroxyl value is 285.7 mgKOH / g. The manufacturer is Huainan Kedi Chemical Technology Co., Ltd., and the brand name is BSA-40.

[0011] The functionality of polycaprolactone diol is 2, the molecular weight is 830, the hydroxyl value is 135 mgKOH / g, the manufacturer is Hunan Juren New Materials Co., Ltd., and the brand number is 2083.

[0012] The functionality of trimethylolpropane polyether polyol is 3, the hydroxyl value is 610 mgKOH / g, the manufacturer is Zhejiang Royal Madrid New Material Technology Co., Ltd., and the brand is HMP-510B.

[0013] The polyurethane heat insulation material for geothermal well oil pipe of the present invention uses a mixture of bisphenol A polyether polyol, polycaprolactone diol and trimethylolpropane polyether polyol as a polyol raw material. The trimethylolpropane polyether polyol has high functionality and high hydroxyl value, so that it has more crosslinking points with -NCO groups, and can form a denser crosslinking network, so that the prepared polyurethane material has excellent mechanical strength and dimensional stability. The aromatic ring and carbon oxygen chain structure in the bisphenol A polyether polyol molecule give the polyurethane material specific rigidity and toughness respectively, and have good corrosion resistance in strong acid and strong alkali environments, thereby improving the chemical resistance and heat resistance of the polyurethane material. The polycaprolactone diol plays the role of elastic crosslinking points in the preparation process, and its addition can improve the tensile strength, tear strength and temperature resistance of the prepared polyurethane material. Thus, the three polyols interact with each other, fundamentally ensuring the mechanical strength of the prepared polyurethane material. 4,4'-dicyclohexylmethane diisocyanate is used as a raw material to react with polyols to ensure the mechanical properties of the prepared polyurethane material. 2,4-diamino-3,5-dimethylthiotoluene is used as a crosslinker and 1,4-butanediamine is used as a chain extender. The amino groups in 2,4-diamino-3,5-dimethylthiotoluene and 1,4-butanediamine can react with isocyanate groups (-NCO) to form urea bonds (-NH-CO-NH-), thereby rapidly expanding the molecular chain and increasing the crosslinking density of the polyurethane network. This crosslinking structure can significantly improve the mechanical strength, tear strength and wear resistance of the polyurethane material. Pentamethyldiethylenetriamine is used as a catalyst to significantly increase the foaming speed of polyurethane foam, shorten the foaming time, balance the overall foaming reaction, improve the pore structure, make the pores more uniform and delicate, and ensure the uniformity and stability of the polyurethane material. Water is used as a foaming agent, and a mixture of modified palygorskite, phenolic hollow microspheres and polyacrylonitrile pre-oxidized fibers is used as a filler. The synergistic effect of palygorskite, phenolic hollow microspheres and polyacrylonitrile pre-oxidized fibers is utilized to improve the thermal insulation performance of polyurethane materials. Among them, the addition of palygorskite can significantly improve the pore structure of the polyurethane material, making its pore size smaller and more evenly distributed, so that the polyurethane material has better thermal insulation performance. Phenolic hollow microspheres have very low thermal conductivity. This low thermal conductivity property enables the phenolic hollow microspheres to form a low thermal conductivity area in the polyurethane material, effectively preventing the transfer of heat, thereby improving the thermal insulation performance of the polyurethane material. In addition, the interior of the phenolic hollow microspheres is a hollow structure, and these closed cells can effectively reduce the convection transfer of heat. The phenolic hollow microspheres with a closed cell structure form a large number of air pockets in the polyurethane material, further reducing the thermal conductivity of the polyurethane material. The polyacrylonitrile pre-oxidized fiber itself has low thermal conductivity, high strength and high modulus. Its addition can enhance the thermal insulation performance and mechanical properties of the prepared polyurethane material.Therefore, the synergistic effect of palygorskite, phenolic hollow microspheres and polyacrylonitrile pre-oxidized fibers fundamentally guarantees the thermal insulation performance of the prepared polyurethane material.

[0014] The preparation method of the polyurethane thermal insulation material for geothermal well oil pipes of the present invention comprises the following steps: adding bisphenol A polyether polyol, polycaprolactone diol, trimethylolpropane polyether polyol, water, 2,4-diamino-3,5-dimethylthiotoluene, 1,4-butanediamine, pentamethyldiethylenetriamine, and a mixture of modified palygorskite, phenolic hollow microspheres and polyacrylonitrile pre-oxidized fibers into a reaction container and mixing them evenly, then adding 4,4'-dicyclohexylmethane diisocyanate and mixing evenly, pouring into a mold preheated to 47-50°C, stirring until foaming is stable, and then performing aging treatment to prepare the polyurethane thermal insulation material for geothermal well oil pipes.

[0015] in: The aging temperature is 55-57°C and the aging time is 2-2.3h.

[0016] Compared with the prior art, the present invention has the following beneficial effects: (1) The polyurethane thermal insulation material for geothermal well oil pipes described in the present invention is prepared by mixing polyester polyol and polyether polyol to react with 4,4'-dicyclohexylmethane diisocyanate to fundamentally ensure the mechanical properties of the prepared polyurethane material. At the same time, 2,4-diamino-3,5-dimethylthiotoluene and 1,4-butanediamine are added to further crosslink and chain extend with isocyanate to promote the polyurethane material to form a tighter crosslinked network structure. In addition, a mixture of modified palygorskite, phenolic hollow microspheres and polyacrylonitrile pre-oxidized fibers is added as a filler to ensure the thermal insulation performance of the prepared polyurethane material. Therefore, the raw materials work synergistically to ensure the mechanical properties and thermal insulation performance of the prepared polyurethane material.

[0017] (2) The method for preparing the polyurethane thermal insulation material for geothermal well oil pipes of the present invention has a simple process, a wide source of raw materials, and easy control of parameters. The prepared polyurethane thermal insulation material has excellent performance. DETAILED DESCRIPTION

[0018] The present invention is further described below with reference to the embodiments.

[0019] Example 1 The polyurethane thermal insulation material for geothermal well oil pipes described in Example 1 is composed of the following raw materials in parts by weight: 29 parts of bisphenol A polyether polyol, 16 parts of polycaprolactone diol, 33 parts of trimethylolpropane polyether polyol, 117 parts of 4,4'-dicyclohexylmethane diisocyanate, 2.9 parts of 2,4-diamino-3,5-dimethylthiotoluene, 3.2 parts of 1,4-butanediamine, 1.56 parts of pentamethyldiethylenetriamine, 5.2 parts of water, and 11 parts of a mixture of modified palygorskite, phenolic hollow microspheres and polyacrylonitrile pre-oxidized fibers; wherein the modified The invention discloses a method for preparing a mixture of modified palygorskite, phenolic hollow microspheres and polyacrylonitrile pre-oxidized fibers, which comprises the following steps: adding palygorskite, phenolic hollow microspheres and polyacrylonitrile pre-oxidized fibers into a mixed solution of γ-methacryloxypropyltrimethoxysilane and anhydrous ethanol, stirring at a speed of 410 r / min for 49 minutes, then filtering and washing with ethanol to remove residual γ-methacryloxypropyltrimethoxysilane, and finally drying at 77°C for 7 hours to prepare a mixture of modified palygorskite, phenolic hollow microspheres and polyacrylonitrile pre-oxidized fibers.

[0020] in: The mass ratio of the mixture of palygorskite, phenolic hollow microspheres and polyacrylonitrile pre-oxidized fibers to the volume ratio of the mixed solution of γ-methacryloxypropyltrimethoxysilane and anhydrous ethanol is 1:22, and the unit is g / mL.

[0021] The mass concentration of γ-methacryloxypropyltrimethoxysilane in the mixed solution of γ-methacryloxypropyltrimethoxysilane and anhydrous ethanol is 1.7%.

[0022] The mass ratio of palygorskite, phenolic hollow microspheres and polyacrylonitrile pre-oxidized fibers is 11:2.85:5.1.

[0023] The manufacturer of phenolic hollow microspheres is Shandong Shengquan Chemical Co., Ltd.

[0024] The manufacturer of polyacrylonitrile pre-oxidized fiber is Shanghai Ibena Textile Technology Co., Ltd.

[0025] The chemical composition of the palygorskite, in terms of mass percentage, is as follows: SiO2 58.10%, MgO 17.24%, Al2O3 11.15%, Fe2O3 1.52%, CaO 0.76%, K2O 0.15%, Na2O 0.15%, and loss on ignition 10.93%.

[0026] The functionality of bisphenol A polyether polyol is 2, and the hydroxyl value is 285.7 mgKOH / g. The manufacturer is Huainan Kedi Chemical Technology Co., Ltd., and the brand name is BSA-40.

[0027] The functionality of polycaprolactone diol is 2, the molecular weight is 830, the hydroxyl value is 135 mgKOH / g, the manufacturer is Hunan Juren New Materials Co., Ltd., and the brand number is 2083.

[0028] The functionality of trimethylolpropane polyether polyol is 3, the hydroxyl value is 610 mgKOH / g, the manufacturer is Zhejiang Royal Madrid New Material Technology Co., Ltd., and the brand is HMP-510B.

[0029] The preparation method of the polyurethane thermal insulation material for geothermal well oil pipe described in Example 1 is composed of the following steps: adding bisphenol A polyether polyol, polycaprolactone diol, trimethylolpropane polyether polyol, water, 2,4-diamino-3,5-dimethylthiotoluene, 1,4-butanediamine, pentamethyldiethylenetriamine, and a mixture of modified palygorskite, phenolic hollow microspheres and polyacrylonitrile pre-oxidized fibers into a reaction container and mixing them evenly, then adding 4,4'-dicyclohexylmethane diisocyanate and mixing evenly, pouring into a mold preheated to 49°C and stirring until the foaming is stable, and then performing a aging treatment to prepare the polyurethane thermal insulation material for geothermal well oil pipe.

[0030] in: The aging temperature is 56°C and the aging time is 2.1h.

[0031] Example 2 The polyurethane thermal insulation material for geothermal well oil pipes described in Example 2 is composed of the following raw materials in parts by weight: 28 parts of bisphenol A polyether polyol, 15 parts of polycaprolactone diol, 34 parts of trimethylolpropane polyether polyol, 115.5 parts of 4,4'-dicyclohexylmethane diisocyanate, 2.8 parts of 2,4-diamino-3,5-dimethylthiotoluene, 3 parts of 1,4-butanediamine, 1.50 parts of pentamethyldiethylenetriamine, 5.3 parts of water, and 12 parts of a mixture of modified palygorskite, phenolic hollow microspheres and polyacrylonitrile pre-oxidized fibers; wherein the modified The invention discloses a method for preparing a mixture of modified palygorskite, phenolic hollow microspheres and polyacrylonitrile pre-oxidized fibers, which comprises the following steps: adding palygorskite, phenolic hollow microspheres and polyacrylonitrile pre-oxidized fibers into a mixed solution of γ-methacryloxypropyltrimethoxysilane and anhydrous ethanol, stirring at a speed of 420 r / min for 50 min, then filtering and washing with ethanol to remove residual γ-methacryloxypropyltrimethoxysilane, and finally drying at 78°C for 7 h to prepare a mixture of modified palygorskite, phenolic hollow microspheres and polyacrylonitrile pre-oxidized fibers.

[0032] in: The mass ratio of the mixture of palygorskite, phenolic hollow microspheres and polyacrylonitrile pre-oxidized fibers to the volume ratio of the mixed solution of γ-methacryloxypropyltrimethoxysilane and anhydrous ethanol is 1:22, and the unit is g / mL.

[0033] The mass concentration of γ-methacryloxypropyltrimethoxysilane in the mixed solution of γ-methacryloxypropyltrimethoxysilane and anhydrous ethanol is 1.7%.

[0034] The mass ratio of palygorskite, phenolic hollow microspheres and polyacrylonitrile pre-oxidized fibers is 12:2.3:4.5.

[0035] The manufacturer of phenolic hollow microspheres is Shandong Shengquan Chemical Co., Ltd.

[0036] The manufacturer of polyacrylonitrile pre-oxidized fiber is Shanghai Ibena Textile Technology Co., Ltd.

[0037] The chemical composition of the palygorskite, in terms of mass percentage, is as follows: SiO2 58.10%, MgO 17.24%, Al2O3 11.15%, Fe2O3 1.52%, CaO 0.76%, K2O 0.15%, Na2O 0.15%, and loss on ignition 10.93%.

[0038] The functionality of bisphenol A polyether polyol is 2, and the hydroxyl value is 285.7 mgKOH / g. The manufacturer is Huainan Kedi Chemical Technology Co., Ltd., and the brand name is BSA-40.

[0039] The functionality of polycaprolactone diol is 2, the molecular weight is 830, the hydroxyl value is 135 mgKOH / g, the manufacturer is Hunan Juren New Materials Co., Ltd., and the brand number is 2083.

[0040] The functionality of trimethylolpropane polyether polyol is 3, the hydroxyl value is 610 mgKOH / g, the manufacturer is Zhejiang Royal Madrid New Material Technology Co., Ltd., and the brand is HMP-510B.

[0041] The preparation method of the polyurethane thermal insulation material for geothermal well oil pipes described in Example 2 comprises the following steps: adding bisphenol A polyether polyol, polycaprolactone diol, trimethylolpropane polyether polyol, water, 2,4-diamino-3,5-dimethylthiotoluene, 1,4-butanediamine, pentamethyldiethylenetriamine, and a mixture of modified palygorskite, phenolic hollow microspheres and polyacrylonitrile pre-oxidized fibers into a reaction container and mixing evenly, then adding 4,4'-dicyclohexylmethane diisocyanate and mixing evenly, pouring into a mold preheated to 47°C and stirring until the foaming is stable, and then performing a aging treatment to prepare the polyurethane thermal insulation material for geothermal well oil pipes.

[0042] in: The aging temperature is 55°C and the aging time is 2h.

[0043] Example 3 The polyurethane thermal insulation material for geothermal well oil pipes described in Example 3 is composed of the following raw materials in parts by weight: 30 parts of bisphenol A polyether polyol, 17 parts of polycaprolactone diol, 32 parts of trimethylolpropane polyether polyol, 118.5 parts of 4,4'-dicyclohexylmethane diisocyanate, 3.0 parts of 2,4-diamino-3,5-dimethylthiotoluene, 3.3 parts of 1,4-butanediamine, 1.62 parts of pentamethyldiethylenetriamine, 5.4 parts of water, and 10 parts of a mixture of modified palygorskite, phenolic hollow microspheres and polyacrylonitrile pre-oxidized fibers; wherein, The invention discloses a method for preparing a mixture of modified palygorskite, phenolic hollow microspheres and polyacrylonitrile pre-oxidized fibers, comprising the following steps: adding palygorskite, phenolic hollow microspheres and polyacrylonitrile pre-oxidized fibers into a mixed solution of γ-methacryloxypropyltrimethoxysilane and anhydrous ethanol, stirring at a speed of 400 r / min for 48 minutes, then filtering and washing with ethanol to remove residual γ-methacryloxypropyltrimethoxysilane, and finally drying at 75°C for 7 hours to prepare a mixture of modified palygorskite, phenolic hollow microspheres and polyacrylonitrile pre-oxidized fibers.

[0044] in: The mass ratio of the mixture of palygorskite, phenolic hollow microspheres and polyacrylonitrile pre-oxidized fibers to the volume ratio of the mixed solution of γ-methacryloxypropyltrimethoxysilane and anhydrous ethanol is 1:22, and the unit is g / mL.

[0045] The mass concentration of γ-methacryloxypropyltrimethoxysilane in the mixed solution of γ-methacryloxypropyltrimethoxysilane and anhydrous ethanol is 1.7%.

[0046] The mass ratio of palygorskite, phenolic hollow microspheres and polyacrylonitrile pre-oxidized fibers is 10:3.4:5.7.

[0047] The manufacturer of phenolic hollow microspheres is Shandong Shengquan Chemical Co., Ltd.

[0048] The manufacturer of polyacrylonitrile pre-oxidized fiber is Shanghai Ibena Textile Technology Co., Ltd.

[0049] The chemical composition of the palygorskite, in terms of mass percentage, is as follows: SiO2 58.10%, MgO 17.24%, Al2O3 11.15%, Fe2O3 1.52%, CaO 0.76%, K2O 0.15%, Na2O 0.15%, and loss on ignition 10.93%.

[0050] The functionality of bisphenol A polyether polyol is 2, and the hydroxyl value is 285.7 mgKOH / g. The manufacturer is Huainan Kedi Chemical Technology Co., Ltd., and the brand name is BSA-40.

[0051] The functionality of polycaprolactone diol is 2, the molecular weight is 830, the hydroxyl value is 135 mgKOH / g, the manufacturer is Hunan Juren New Materials Co., Ltd., and the brand number is 2083.

[0052] The functionality of trimethylolpropane polyether polyol is 3, the hydroxyl value is 610 mgKOH / g, the manufacturer is Zhejiang Royal Madrid New Material Technology Co., Ltd., and the brand is HMP-510B.

[0053] The preparation method of the polyurethane thermal insulation material for geothermal well oil pipes described in this embodiment 3 consists of the following steps: adding bisphenol A polyether polyol, polycaprolactone diol, trimethylolpropane polyether polyol, water, 2,4-diamino-3,5-dimethylthiotoluene, 1,4-butanediamine, pentamethyldiethylenetriamine, and a mixture of modified palygorskite, phenolic hollow microspheres and polyacrylonitrile pre-oxidized fibers into a reaction container and mixing evenly, then adding 4,4'-dicyclohexylmethane diisocyanate and mixing evenly, pouring into a mold preheated to 50°C and stirring until the foaming is stable, and then performing a aging treatment to prepare the polyurethane thermal insulation material for geothermal well oil pipes.

[0054] in: The aging temperature is 57°C and the aging time is 2.3h.

[0055] Comparative Example 1 The preparation method of the polyurethane thermal insulation material for geothermal well oil pipe described in this comparative example 1 is the same as that in Example 1, and the only difference is that the raw material composition is different. The polyurethane thermal insulation material for geothermal well oil pipe described in this comparative example 1 is composed of the following raw materials in parts by weight: 29 parts of bisphenol A polyether polyol, 16 parts of polycaprolactone diol, 33 parts of trimethylolpropane polyether polyol, 117 parts of 4,4'-dicyclohexylmethane diisocyanate, 2.9 parts of 2,4-diamino-3,5-dimethylthiotoluene, 3.2 parts of 1,4-butanediamine, 1.56 parts of pentamethyldiethylenetriamine, and 5.2 parts of water.

[0056] The polyurethane thermal insulation materials prepared in Examples 1-3 and Comparative Example 1 were subjected to performance tests, wherein the thermal conductivity was tested in accordance with GB / T 10294-2008 "Determination of Steady-State Thermal Resistance and Related Properties of Insulating Materials - Protective Hot Plate Method"; the compressive strength was tested in accordance with GB / T 8813-2020 "Determination of Compression Properties of Rigid Foam Plastics"; the density was tested in accordance with GB / T6343-2009 "Determination of Apparent Density of Foam Plastics and Rubber"; the dimensional stability was tested in accordance with SY / T 0415-96 "Technical Standard for Anti-corrosion Insulation Layer of Rigid Polyurethane Foam Plastics for Buried Steel Pipelines", the test temperature was 100°C, and the test time was 96h; the results are shown in Table 1 below.

[0057] Table 1 Test results of polyurethane thermal insulation material performance

Claims

1. A polyurethane thermal insulation material for geothermal well oil pipe, characterized by: The invention is composed of the following raw materials in parts by weight: 28-30 parts of bisphenol A polyether polyol, 15-17 parts of polycaprolactone diol, 32-34 parts of trimethylolpropane polyether polyol, 115.5-118.5 parts of 4,4'-dicyclohexylmethane diisocyanate, 2.8-3.0 parts of 2,4-diamino-3,5-dimethylthiotoluene, 3-3.3 parts of 1,4-butanediamine, 1.50-1.62 parts of pentamethyldiethylenetriamine, 5-5.4 parts of water, and 10-12 parts of a mixture of modified palygorskite, phenolic hollow microspheres and polyacrylonitrile pre-oxidized fibers; wherein the modified The invention discloses a method for preparing a mixture of modified palygorskite, phenolic hollow microspheres and polyacrylonitrile pre-oxidized fibers, which comprises the following steps: adding palygorskite, phenolic hollow microspheres and polyacrylonitrile pre-oxidized fibers into a mixed solution of γ-methacryloxypropyltrimethoxysilane and anhydrous ethanol, stirring at a speed of 400-420 r / min for 48-50 min, then filtering and washing with ethanol to remove residual γ-methacryloxypropyltrimethoxysilane, and finally drying at 75-78°C for 7h to prepare a mixture of modified palygorskite, phenolic hollow microspheres and polyacrylonitrile pre-oxidized fibers.

2. The polyurethane thermal insulation material for geothermal well oil pipe according to claim 1, characterized in that: The mass ratio of the mixture of palygorskite, phenolic hollow microspheres and polyacrylonitrile pre-oxidized fibers to the volume ratio of the mixed solution of γ-methacryloxypropyltrimethoxysilane and anhydrous ethanol is 1:22, and the unit is g / mL.

3. The polyurethane thermal insulation material for geothermal well oil pipe according to claim 1, characterized in that: The mass concentration of γ-methacryloxypropyltrimethoxysilane in the mixed solution of γ-methacryloxypropyltrimethoxysilane and anhydrous ethanol is 1.7%.

4. The polyurethane thermal insulation material for geothermal well oil pipe according to claim 1, characterized in that: The mass ratio of palygorskite, phenolic hollow microspheres and polyacrylonitrile pre-oxidized fibers is 10-12: 2.3-3.4: 4.5-5.

7.

5. The polyurethane thermal insulation material for geothermal well oil pipe according to claim 1, characterized in that: The chemical composition of the palygorskite, in terms of mass percentage, is as follows: SiO2 58.10%, MgO 17.24%, Al2O3 11.15%, Fe2O3 1.52%, CaO 0.76%, K2O 0.15%, Na2O 0.15%, and loss on ignition 10.93%.

6. The polyurethane thermal insulation material for geothermal well oil pipe according to claim 1, characterized in that: The functionality of bisphenol A polyether polyol is 2, and the hydroxyl value is 285.7 mgKOH / g.

7. The polyurethane thermal insulation material for geothermal well oil pipe according to claim 1, characterized in that: The functionality of polycaprolactone diol is 2, the molecular weight is 830, and the hydroxyl value is 135 mgKOH / g.

8. The polyurethane thermal insulation material for geothermal well oil pipe according to claim 1, characterized in that: The functionality of trimethylolpropane polyether polyol is 3, and the hydroxyl value is 610 mgKOH / g.

9. A method for preparing the polyurethane thermal insulation material for geothermal well oil pipe according to claim 1, characterized in that: The method comprises the following steps: adding bisphenol A polyether polyol, polycaprolactone diol, trimethylolpropane polyether polyol, water, 2,4-diamino-3,5-dimethylthiotoluene, 1,4-butanediamine, pentamethyldiethylenetriamine, a mixture of modified palygorskite, phenolic hollow microspheres and polyacrylonitrile pre-oxidized fibers into a reaction container and mixing them evenly; then adding 4,4'-dicyclohexylmethane diisocyanate and mixing evenly; pouring the mixture into a mold preheated to 47-50°C, stirring the mixture until the foaming is stable, and then subjecting the mixture to aging treatment to prepare a polyurethane thermal insulation material for geothermal well oil pipes.

10. The method for preparing the polyurethane thermal insulation material for geothermal well oil pipe according to claim 9, characterized in that: The aging temperature is 55-57°C and the aging time is 2-2.5h.

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