An isocyanate composition, a modified composition and a polyurethane elastomer

Abstract

The present invention provides an isocyanate composition, a modified composition and a polyurethane elastomer. The effective factor of the isocyanate composition is 3.80 - 5.30. Through the design and control of the effective factor, it has excellent reaction activity and can be used for the preparation of high-performance polyurethane products. The isocyanate composition can improve the stability of polyurethane products, especially can significantly enhance the color fastness and weather resistance of the polyurethane elastomer, inhibit the increase of color number and yellowing under humid and hot conditions, and improve the tensile strength and tear strength of the polyurethane elastomer, so that the polyurethane elastomer has excellent comprehensive performance in terms of weather resistance, stability and mechanical properties.

Description

Technical Field

[0001] The present invention belongs to the technical field of isocyanates, and particularly relates to an isocyanate composition, a modified composition and a polyurethane elastomer. Background Art

[0002] Polyurethane elastomers (PUR) have the characteristics of high elasticity, high strength, wide hardness range, good wear resistance, etc., and are applied in industries such as the automotive industry, machinery industry, medical industry, transportation, sports goods, electronics industry, chemical industry, coal, etc. Polyurethane elastomers can be divided into TDI (toluene diisocyanate) type, MDI (diphenylmethane diisocyanate) type, PPDI (phenylene diisocyanate) type, NDI (naphthalene diisocyanate) type, CHDI (cyclohexane diisocyanate) type, etc. according to the different isocyanates used, and the TDI type and MDI type are the most common.

[0003] With the expansion of the application scope of polyurethane elastomers, the commonly used TDI-type PUR and MDI-type PUR can no longer meet the usage requirements, and new polyurethane elastomers have been developed in order to obtain improved elastomer properties. For example, CN113354788A discloses a polyurethane elastomer with good heat resistance and anti-slip properties, and the raw materials include: 60-65% of polyester polyol, 30-33% of diisocyanate, and 1-9.5% of a mixed chain extender crosslinking agent. The diisocyanate includes a combination of dimethylbiphenyl diisocyanate, p-phenylene diisocyanate and 1,5-naphthalene diisocyanate. CN104017166A discloses a preparation method of a high-temperature resistant thermoplastic polyurethane elastomer. The steps are: adding an antioxidant, a catalyst and molten polyester polyol into a reaction kettle, dehydrating under heating and reduced pressure conditions to form component A; heating and melting the diisocyanate to form component B; mixing molten triol and molten diol evenly, dehydrating under reduced pressure and heating conditions to form component C; adding component A, component B and component C into a twin-screw extruder at the same time, and obtaining a high-temperature resistant thermoplastic polyurethane elastomer through a step-by-step polymerization reaction; the diisocyanate is a mixture composed of 70-100% of trans-1,4-CHDI and 0-30% of cis-1,4-CHDI by mass percentage. CN104817683A discloses a polyurethane elastomer with good mechanical properties and fatigue resistance. Its raw materials include component A and component B. By weight, component A is: 100 parts of macromolecular diol, 5-20 parts of NDI, 10-30 parts of p-phenylene diisocyanate or 10-50 parts of 3,3'-dimethyl-4,4'-biphenyl diisocyanate (TODI); component B is: 0-100 parts of macromolecular diol, 8-30 parts of chain extender, 0.02-0.5 parts of catalyst; the weight ratio of component A to component B is 100:(8-30).

[0004] Compared with common MDI and TDI, NDI, PPDI, and CHDI have higher melting points and belong to high-melting-point isocyanates. Moreover, NDI and PPDI have an aromatic structure and a large steric hindrance effect. Therefore, the synthesized polyurethane elastomers have characteristics such as high hardness, good resilience, excellent heat resistance, outstanding dynamic performance, and good wear resistance, and can be applied to high-dynamic-load scenarios. They are favored isocyanate raw materials in the preparation of new polyurethane elastomers. However, despite the various advantages of NDI, PPDI, and CHDI, they also have undeniable disadvantages: due to the high reactivity of the NCO group, it may cause unnecessary color number growth in the production of polyurethanes, that is, obvious yellowing occurs, and the weather resistance is poor, thus seriously affecting the appearance and product quality of polyurethane elastomers.

[0005] Therefore, there is an urgent need in the art to develop isocyanate raw materials with more excellent performance to improve the weather resistance, appearance, and other properties of polyurethane elastomers. Summary of the Invention

[0006] Aiming at the deficiencies of the prior art, the purpose of the present invention is to provide an isocyanate composition, a modified composition, and a polyurethane elastomer. Through the design of effective factors, the isocyanate composition can effectively inhibit the color number growth of polyurethane elastomers under humid and hot conditions, significantly improve the stability and weather resistance of polyurethane elastomers, and improve the mechanical properties of polyurethane elastomers.

[0007] To achieve the purpose of this invention, the following technical solutions are adopted in the present invention:

[0008] In the first aspect, the present invention provides an isocyanate composition, and the effective factor of the isocyanate composition is 3.80 - 5.30.

[0009] The calculation formula of the effective factor is shown in Formula I:

[0010]

[0011] In Formula I, E is the effective factor;

[0012] In Formula I, A is the mass content of chlorine in the isocyanate composition;

[0013] In Formula I, B is the mass content of chloro-isocyanate in the isocyanate composition;

[0014] In Formula I, M Cl is the relative atomic mass of chlorine, approximately 35.5;

[0015] In Formula I, M B is the relative molecular mass of the chloro-isocyanate.

[0016] The effective factor E of the isocyanate composition provided by the present invention is 3.80 - 5.30. For example, it can be 3.90, 4.00, 4.10, 4.30, 4.50, 4.70, 4.90, 5.00, 5.10 or 5.20, as well as specific point values between the above point values. Due to space limitations and for the sake of simplicity, the present invention does not exhaustively list the specific point values included in the said range.

[0017] In the present invention, the isocyanate composition includes a combination of isocyanate and chlorine-containing substances, so it is named "isocyanate composition"; the chlorine-containing substances include a combination of chloro isocyanate and substances corresponding to the effective factor. Through the design and control of the effective factor, the isocyanate composition of the present invention includes chlorine-containing substances with specific contents and specific types, making it have excellent reaction activity and capable of being used in the preparation of high-performance polyurethane products. In particular, when the isocyanate composition is used in polyurethane products, especially polyurethane elastomers, it can significantly improve the stability and weather resistance of the polyurethane elastomer, inhibit the increase in color number and yellowing under humid and hot conditions, improve the tensile strength and tear strength of the polyurethane elastomer, and enable the polyurethane elastomer to have excellent comprehensive performance in terms of weather resistance, stability, mechanical properties and appearance.

[0018] Preferably, the isocyanate is a diisocyanate, and further preferably includes any one or a combination of at least two of naphthalene diisocyanate (NDI), phenylene diisocyanate (PPDI), cyclohexane diisocyanate (CHDI), diphenylmethane diisocyanate (MDI), and toluene diisocyanate (TDI).

[0019] In the present invention, unless otherwise specified, the listed isocyanates include all their isomers. For example, the naphthalene diisocyanate (NDI) is The phenylene diisocyanate (PPDI) is The cyclohexane diisocyanate (CHDI) is The diphenylmethane diisocyanate (MDI) is The toluene diisocyanate (TDI) is Preferably

[0020] Preferably, the naphthalene diisocyanate is 1,5-naphthalene diisocyanate The phenylene diisocyanate is 1,4-phenylene diisocyanate (p-phenylene diisocyanate, );The cyclohexane diisocyanate is 1,4-cyclohexane diisocyanate The diphenylmethane diisocyanate is 4,4'-diphenylmethane diisocyanate The toluene diisocyanate is 2,4-toluene diisocyanate and / or 2,6-toluene diisocyanate

[0021] Preferably, the mass percentage content of isocyanate in the isocyanate composition is ≥97%, such as 97.5%, 98%, 98.5%, 99%, 99.1%, 99.2%, 99.3%, 99.4%, 99.5%, 99.6%, 99.7%, 99.8%, 99.9%, 99.92%, 99.95%, 99.98%, 99.99%, etc., more preferably ≥99%, still more preferably >99%.

[0022] Preferably, the chloro isocyanate is a compound obtained by replacing one NCO group in the isocyanate with chlorine.

[0023] Preferably, the chloro isocyanate includes (preferably chloronaphthyl isocyanate CNI, the isocyanate is NDI), (chlorophenyl isocyanate CPPI, the isocyanate is PPDI), (chlorocyclohexyl isocyanate CCHI, the isocyanate is CHDI), (preferably chlorodiphenylmethane isocyanate, the isocyanate is MDI), (preferably chlorotoluene isocyanate, the isocyanate is TDI) or any combination of at least two of them.

[0024] In this article, the expression of the ring structure crossed by “—” indicates that the connection site is at any bond-forming position on the ring structure.

[0025] Preferably, the mass content (B value) of chloro isocyanate in the isocyanate composition is 5-2000 ppm, such as 10 ppm, 20 ppm, 30 ppm, 50 ppm, 80 ppm, 100 ppm, 300 ppm, 500 ppm, 700 ppm, 900 ppm, 1000 ppm, 1100 ppm, 1300 ppm, 1500 ppm, 1700 ppm or 1900 ppm, as well as the specific point values between the above point values. Due to space limitations and for the sake of simplicity, the present invention does not exhaustively list the specific point values included in the range. More preferably, it is 10-1500 ppm.

[0026] In the present invention, “ppm” is parts per million ratio, 1 ppm represents one in a million; when the same expression is involved hereinafter, it has the same meaning.

[0027] Preferably, the substance corresponding to the effective factor includes any one or a combination of at least two of the following compounds: Among them, R is a divalent group obtained by removing the NCO group in the isocyanate.

[0028] Preferably, the R is selected from (the isocyanate is NDI), (the isocyanate is PPDI), (the isocyanate is CHDI), (the isocyanate is MDI), (preferably the isocyanate is TDI) or a combination of any one or at least two of them; among them, the wavy line represents the connection site of the group.

[0029] Preferably, the mass content of chlorine (A value) in the isocyanate composition is 1-1000 ppm, for example, it can be 2 ppm, 5 ppm, 8 ppm, 10 ppm, 30 ppm, 50 ppm, 80 ppm, 100 ppm, 150 ppm, 200 ppm, 250 ppm, 300 ppm, 350 ppm, 400 ppm, 450 ppm, 500 ppm, 550 ppm, 600 ppm, 650 ppm, 700 ppm, 750 ppm, 800 ppm, 850 ppm, 900 ppm or 950 ppm, as well as the specific point values between the above point values. Due to space limitations and for the sake of simplicity, the specific point values included in the scope of the present invention are not exhaustively listed herein. Further preferably, it is 5-500 ppm.

[0030] In the present invention, in formula I for calculating the effective factor, A is the mass content of chlorine in the isocyanate composition, preferably obtained by testing with X-ray fluorescence spectrometry (XRF).

[0031] Preferably, in formula I for calculating the effective factor, B is the mass content of chloro-isocyanate in the isocyanate composition, obtained by testing with chromatography-mass spectrometry, preferably obtained by testing with gas chromatography-mass spectrometry (GCMS).

[0032] In the research of the present invention, it is found that the characterization methods of chlorine content in isocyanates known in the prior art are difficult to accurately control the properties of isocyanates, and thus the properties of polyurethane products / polyurethane elastomers, especially yellowing resistance, stability and appearance, etc. cannot be effectively controlled. Specifically, the test method for total chlorine content in Standard GB / T 12009.1-1989 is the oxygen flask combustion method. After converting all chlorine (including bromine) in the isocyanate into inorganic chlorine (including bromine), silver nitrate titration is then used. It characterizes all the chlorine content in the isocyanate, and also includes the bromine content in the isocyanate. Standard GB / T 12009.2-2016 measures the content of hydrolyzable chlorine. Specifically, it is the chlorine released after the reaction of isocyanate with alcohol and water, which is the chlorine with higher activity in the isocyanate, and also includes bromine with higher activity. Some monochloro isocyanates can also hydrolyze a part. The chlorine (including a part of bromine) content measured by GB / T12009.1-1989 or GB / T 12009.2-2016 cannot accurately represent the component information of the isocyanate, and thus the properties of isocyanates, polyurethane products, especially polyurethane elastomers cannot be effectively controlled.

[0033] As a preferred technical solution of the present invention, in the calculation of the effective factor E, A is the total chlorine content (excluding bromine) obtained by XRF test, and B is the content of chloro isocyanate obtained by gas chromatography-mass spectrometry. The A value and B value are obtained by accurate qualitative and quantitative analysis methods, so that the effective factor E accurately characterizes the polychlorinated substances and part of the hydrolyzable chlorine (excluding the hydrolyzable chlorine of monochloro isocyanate) in the isocyanate composition, corresponding to a more refined and clear chlorine content. This part of the chlorine content plays a key role in the activity of the isocyanate and the properties of polyurethane products (such as polyurethane elastomers), thus realizing the performance regulation of the isocyanate composition, and further improving the properties of the polyurethane elastomer prepared therefrom, especially having an obvious improvement effect on weather resistance, stability, mechanical properties and appearance.

[0034] It should be noted that in the present invention, the chloro isocyanate and the substances corresponding to the effective factor can be produced as by-products during the preparation of the isocyanate, or can be artificially added to obtain the required content.

[0035] In the second aspect, the present invention provides a preparation method of the isocyanate composition as described in the first aspect. The preparation method includes: reacting an amine compound with phosgene to obtain the isocyanate composition.

[0036] Preferably, the preparation method includes the following steps:

[0037] (1) Reacting an amine compound with phosgene to obtain a reaction product;

[0038] (2) The reaction product obtained in step (1) is subjected to a removal treatment to obtain a crude product; the removal treatment includes phosgene removal treatment and / or solvent removal treatment;

[0039] (3) The crude product obtained in step (2) is successively separated and refined to obtain the isocyanate composition.

[0040] It should be noted that when an isocyanation reaction is carried out between a diamine and phosgene, specific effective factors can be obtained by preferably the following parameters. The effective factor E of the isocyanate composition can also be adjusted by adding a chloro isocyanate and / or a substance corresponding to the effective factor to the isocyanate.

[0041] Preferably, in step (3), the separation gives a heavy fraction and an intermediate product; the mixture of the intermediate product and the heavy fraction is refined to obtain the isocyanate composition; the mass percentage of the heavy fraction in the mixture is 1-10%.

[0042] As a preferred technical solution of the present invention, the component to be refined is the mixture of the intermediate product and the heavy fraction, and the mass percentage of the heavy fraction in the mixture is 1-10%, for example, it can be 2%, 3%, 4%, 5%, 6%, 7%, 8% or 9%, as well as the specific point values between the above point values. Due to space limitations and for the sake of brevity, the present invention does not exhaustively list the specific point values included in the range, and further preferably 2-10%.

[0043] Preferably, the separated heavy fraction can be directly mixed with the intermediate product to obtain a mixture; or, the separated heavy fraction is a primary heavy fraction, and the primary heavy fraction is separated again to obtain a heavy fraction recovery material and a residual heavy fraction; the heavy fraction recovery material is mixed with the intermediate product to obtain the mixture; the mass percentage of the heavy fraction recovery material in the mixture is 1-10%.

[0044] In another preferred technical solution, the preparation method of the isocyanate composition includes: mixing the isocyanate obtained by the carbamate pyrolysis method with the heavy fraction recovery material to obtain the isocyanate composition. Preferably, the mass percentage of the heavy fraction recovery material in the isocyanate composition is 1-10% (such as 2%, 3%, 4%, 5%, 6%, 7%, 8% or 9%, etc.), and further preferably 1-5%.

[0045] As a preferred technical solution of the present invention, the preparation method of the isocyanate composition is the phosgenation method, that is, an amine compound reacts with phosgene to generate an isocyanate; the amine compound includes a diamine and / or a diamine salt (such as a diamine hydrochloride obtained by reacting a diamine with HCl).

[0046] Preferably, the methods for reacting the amine compound with phosgene are exemplarily classified into the following three categories: the method of reacting diamine with phosgene in the gas phase, also known as the gas-phase phosgenation method; the method of reacting diamine with phosgene in the liquid phase, also known as the liquid-phase phosgenation method or the cold-hot two-stage phosgenation method; the method of reacting diamine salt (such as diamine hydrochloride) with phosgene in a solvent, also known as the phosgenation method of diamine hydrochloride. The present invention further preferably adopts the cold-hot two-stage phosgenation method.

[0047] Preferably, the amine compound in step (1) is diamine, and the method of the reaction in step (1) is the cold-hot two-stage phosgenation method.

[0048] Preferably, step (1) specifically includes: mixing diamine with a solvent to obtain an amine solution; introducing phosgene into the amine solution for reaction to obtain a reaction product, i.e., a reaction liquid containing diisocyanate.

[0049] Preferably, the solvent is an organic solvent, exemplarily including but not limited to: aromatic hydrocarbons such as benzene, toluene, and xylene; aliphatic hydrocarbons such as octane and decane; cycloaliphatic hydrocarbons such as cyclohexane, methylcyclohexane, and ethylcyclohexane; halogenated aromatic hydrocarbons such as chlorotoluene, chlorobenzene, dichlorobenzene, dibromobenzene, and trichlorobenzene; nitrogen-containing compound classes such as nitrobenzene, N,N-dimethylformamide, N,N-dimethylacetamide, and N,N'-dimethylimidazolinone; ethers such as dibutyl ether, ethylene glycol dimethyl ether, and ethylene glycol diethyl ether; ketones such as heptanone, diisobutyl ketone, methyl isobutyl ketone, and methyl ethyl ketone; fatty acid esters such as ethyl acetate, butyl acetate, amyl acetate, and ethoxyethyl acetate; aromatic carboxylic acid esters such as methyl salicylate, dimethyl phthalate, dibutyl phthalate, and methyl benzoate, etc.; the solvent can be used alone or in combination of at least two.

[0050] Preferably, the solvent includes halogenated aromatic hydrocarbons, and further preferably chlorobenzene and / or dichlorobenzene.

[0051] Preferably, the mass percentage content of diamine in the amine solution is 1-50 wt.%, for example, it can be 2 wt.%, 5 wt.%, 8 wt.%, 10 wt.%, 12 wt.%, 15 wt.%, 18 wt.%, 20 wt.%, 22 wt.%, 25 wt.%, 28 wt.%, 30 wt.%, 35 wt.%, 40 wt.%, 45 wt.% or 48 wt.%, as well as the specific point values between the above point values. Due to space limitations and for the sake of simplicity, the present invention does not exhaustively list the specific point values included in the above range, and further preferably 5-40 wt.%.

[0052] Preferably, the molar ratio of phosgene to the amine compound (diamine) in step (1) is (3 - 50):1, for example, it can be 4:1, 5:1, 8:1, 10:1, 12:1, 15:1, 18:1, 20:1, 22:1, 25:1, 28:1, 30:1, 32:1, 35:1, 38:1, 40:1, 42:1, 45:1 or 48:1, etc. Further preferably, it is (4 - 40):1, and even more preferably, it is (4 - 30):1.

[0053] Preferably, the reaction in step (1) includes a cold reaction and a hot reaction carried out successively.

[0054] Preferably, the temperature of the cold reaction is from -10°C to 80°C, for example, it can be -5°C, 0°C, 5°C, 10°C, 15°C, 20°C, 25°C, 30°C, 35°C, 40°C, 45°C, 50°C, 55°C, 60°C, 65°C, 70°C or 75°C, as well as the specific point values between the above point values. Due to space limitations and for the sake of simplicity, the present invention does not exhaustively list the specific point values included in the range. Further preferably, it is 0 - 70°C.

[0055] Preferably, the time of the cold reaction is 1 - 20 h, for example, it can be 2 h, 3 h, 4 h, 5 h, 6 h, 7 h, 8 h, 9 h, 10 h, 11 h, 12 h, 13 h, 14 h, 15 h, 16 h, 17 h, 18 h or 19 h, as well as the specific point values between the above point values. Due to space limitations and for the sake of simplicity, the present invention does not exhaustively list the specific point values included in the range. Further preferably, it is 2 - 15 h.

[0056] Preferably, the temperature of the hot reaction is 70 - 150°C, for example, it can be 75°C, 80°C, 85°C, 90°C, 95°C, 100°C, 105°C, 110°C, 115°C, 120°C, 125°C, 130°C, 135°C, 140°C or 145°C, as well as the specific point values between the above point values. Due to space limitations and for the sake of simplicity, the present invention does not exhaustively list the specific point values included in the range. Further preferably, it is 80 - 130°C.

[0057] Preferably, the time of the hot reaction is 1 - 20 h, for example, it can be 2 h, 3 h, 4 h, 5 h, 6 h, 7 h, 8 h, 9 h, 10 h, 11 h, 12 h, 13 h, 14 h, 15 h, 16 h, 17 h, 18 h or 19 h, as well as the specific point values between the above point values. Due to space limitations and for the sake of simplicity, the present invention does not exhaustively list the specific point values included in the range. Further preferably, it is 2 - 15 h.

[0058] Preferably, the reaction in step (1) is carried out under normal pressure or pressurized conditions.

[0059] Preferably, the pressure (gauge pressure) of the reaction in step (1) is 0 - 0.6 MPa G. For example, it can be 0.0005 MPa G, 0.001 MPa G, 0.003 MPa G, 0.01 MPa G, 0.02 MPa G, 0.03 MPa G, 0.05 MPa G, 0.07 MPa G, 0.09 MPa G, 0.1 MPa G, 0.2 MPa G, 0.3 MPa G, 0.4 MPa G or 0.5 MPa G, as well as specific point values between the above point values. Due to space limitations and for the sake of simplicity, the present invention does not exhaustively list all the specific point values included in the range. Further preferably, it is 0.005 - 0.4 MPa G, and even more preferably 0.01 - 0.2 MPa G.

[0060] Preferably, the reaction in step (1) (isocyanate chemical process) is a batch process or a continuous process, and a continuous process is preferred.

[0061] Among them, the continuous process means that the slurry (amine solution) in the stirring tank is continuously transported from the stirring tank to a reaction tank different from the stirring tank, and diamine reacts with phosgene in the reaction tank, and the obtained reaction product (reaction liquid containing diisocyanate) is continuously taken out from the reaction tank. The present invention does not specifically limit the number of reaction kettles in the continuous process. Exemplarily, it can be 2, 3, 4, 5 or more.

[0062] According to needs, a removal process (solvent removal process and / or phosgene removal process) and a separation and purification process can be implemented on the reaction product obtained in step (1).

[0063] Preferably, the phosgene removal treatment in step (2) is carried out in a phosgene removal tower.

[0064] Preferably, the solvent removal treatment in step (2) is carried out in a solvent removal tower.

[0065] Preferably, the separation in step (3) separates the intermediate product (light components) and the heavy components to achieve the removal of the heavy components; the separation device includes, but is not limited to, a short-path evaporator, a distillation column, and a short-path evaporator is further preferred.

[0066] Preferably, the operating pressure of the short-path evaporator is 0.05 - 4 kPa, for example, it can be 0.08 kPa, 0.1 kPa, 0.3 kPa, 0.5 kPa, 0.8 kPa, 1 kPa, 1.2 kPa, 1.5 kPa, 1.8 kPa, 2 kPa, 2.2 kPa, 2.5 kPa, 2.8 kPa, 3 kPa, 3.2 kPa, 3.5 kPa or 3.8 kPa, as well as the specific point values between the above point values. Due to space limitations and for the sake of simplicity, the specific point values included in the scope of the present invention are not exhaustively listed. Further preferably, it is 0.1 - 2.5 kPa.

[0067] As a preferred technical solution of the present invention, the separated heavy components contain chlorine-containing substances with a relatively rich variety and high content. By incorporating the separated heavy components or the heavy component recycle obtained by re-separating the heavy components into the separated intermediate product (light components) in a certain proportion and then refining it, the variety and content of chlorine-containing substances in the product can be effectively regulated, so that the effective factor of the isocyanate composition is 3.80 - 5.30.

[0068] Preferably, the mass percentage content of the heavy components (heavy component recycle) in the mixture (the material participating in the refining) is 1 - 10%, further preferably 2 - 10%, so that the effective factor of the isocyanate composition is 3.80 - 5.30. If the incorporation amount of the heavy components (heavy component recycle) is too small, the effective factor is too high, and the reaction rate is too fast when the isocyanate composition is used to prepare polyurethane elastomers, resulting in uneven polymerization and poor mechanical properties of the polyurethane elastomers, with reduced tensile strength and tear strength; if the incorporation amount of the heavy components (heavy component recycle) is too high, the effective factor is too low, and the isocyanate composition contains more impurities, making the weather resistance of the polyurethane elastomers poor, especially with obvious yellowing under humid and hot conditions.

[0069] Preferably, the heavy components mixed with the intermediate product can be directly incorporated into the intermediate product, or can be obtained as a heavy component recycle after being separated by a de-heavy component device through cyclic separation and then incorporated into the intermediate product.

[0070] Preferably, the refining method is an industrial separation technology known in the art, exemplarily including but not limited to: distillation, rectification, crystallization, etc.

[0071] Preferably, the refining method is rectification.

[0072] Preferably, the rectification is carried out in a rectification column, and the rectification column preferably includes a plate rectification column or a packed rectification column.

[0073] Preferably, the number of theoretical plates of the distillation column is 2 - 40, for example, it can be 3, 5, 8, 10, 12, 15, 18, 20, 22, 25, 28, 30, 32, 35 or 38, as well as the specific point values between the above point values. Due to space limitations and for the sake of brevity, the present invention does not exhaustively list the specific point values included in the range. Further preferably, it is 5 - 20.

[0074] Preferably, the top pressure of the distillation column is 0.1 - 4 kPa, for example, it can be 0.2 kPa, 0.5 kPa, 0.8 kPa, 1 kPa, 1.2 kPa, 1.5 kPa, 1.8 kPa, 2 kPa, 2.2 kPa, 2.5 kPa, 2.8 kPa, 3 kPa, 3.2 kPa, 3.5 kPa or 3.8 kPa, as well as the specific point values between the above point values. Due to space limitations and for the sake of brevity, the present invention does not exhaustively list the specific point values included in the range. Further preferably, it is 0.15 - 2.5 kPa.

[0075] Preferably, the top reflux ratio of the distillation column is 0.01 - 40, for example, it can be 0.05, 0.1, 0.5, 1, 3, 5, 8, 10, 12, 15, 18, 20, 22, 25, 28, 30, 32, 35 or 38, as well as the specific point values between the above point values. Due to space limitations and for the sake of brevity, the present invention does not exhaustively list the specific point values included in the range. Further preferably, it is 0.1 - 20.

[0076] In a preferred technical solution of the present invention, the method for preparing the isocyanate composition comprises the following steps:

[0077] (1) Phosgenation process: Mix diamine with a solvent to obtain an amine solution; introduce phosgene into the amine solution to react, obtaining a reaction product; the reaction includes a cold reaction and a hot reaction that are carried out successively, and the temperature of the cold reaction < the temperature of the hot reaction;

[0078] (2) Removal process: Carry out a removal treatment on the reaction product obtained in step (1) to obtain a crude product; the removal treatment includes phosgene removal treatment and / or solvent removal treatment;

[0079] (3a) Separation process: Separate the crude product obtained in step (2) to obtain a heavy component and an intermediate product (light component);

[0080] (3b) Recombinant fraction recovery process: Mix the intermediate product obtained in step (3a) with the recombinant fraction to obtain a mixture; the mass percentage of the recombinant fraction in the mixture is 1-10%; or, perform secondary separation on the recombinant fraction obtained in step (3a) to obtain a recombinant fraction recovery material and a residual recombinant fraction; mix the recombinant fraction recovery material with the intermediate product to obtain a mixture; the mass percentage of the recombinant fraction recovery material in the mixture is 1-10%.

[0081] (3c) Refining process: Refine the mixture obtained in step (3b) to obtain the isocyanate composition.

[0082] Exemplarily, the process flow diagram of the preparation method is as Figure 1 shown, including a phosgenation process 10, a removal process 20, a separation process 30, a recombinant fraction recovery process 40, and a refining process 50. Among them, the phosgenation process can be implemented in an intermittent or continuous manner, and the continuous manner is carried out continuously in a kettle. By appropriately adjusting the mixing ratio of the recombinant fraction and the intermediate product, the supply ratio of phosgene, the reaction temperature, the reaction pressure, the average residence time, the reflux ratio of the distillation column, etc., the effective factor of the isocyanate composition is adjusted, and the control of the effective factor is mainly achieved through the ratio of the recombinant fraction to the intermediate product.

[0083] Specifically, taking the NDI composition as an example, its preparation method is as follows:

[0084] (1) Phosgenation process: Adopt a kettle reaction, three or four kettles in series, continuously transport the amine solution containing NDA (naphthalenediamine) to the phosgenation reaction kettle, and continuously introduce phosgene into the tops of each of the cold reaction kettle, the first hot reaction kettle, and the second hot reaction kettle in the above-mentioned ratio in an inserted tube manner; then, while maintaining the inside of the cold reaction kettle at the temperature and reaction pressure of the above-mentioned cold reaction, stir and mix the amine solution and phosgene; thus, NDA and phosgene (carbonyl chloride) undergo a cold reaction to obtain a cold reaction photochemical solution.

[0085] Then, continuously transport the above-mentioned cold reaction photochemical solution to the top of the first hot reaction kettle; that is, while continuously supplying the amine solution and phosgene to the cold reaction kettle, continuously take out the cold reaction photochemical solution from the cold reaction kettle and transport it to the first hot reaction kettle.

[0086] Next, maintain the inside of the first hot reaction kettle at the temperature and reaction pressure of the above-mentioned hot reaction, stir and mix the reaction substances and phosgene in the first hot reaction kettle and carry out a phosgenation reaction; similarly, the second hot reaction kettle also carries out a phosgenation reaction while inputting the reaction substances.

[0087] Thus, the phosgenation process is continuously implemented to obtain a reaction solution containing NDI.

[0088] (2) Removal process: It is carried out by using a degassing tower and a solvent removal tower, and the above reaction liquid is continuously fed to the middle part of the degassing tower. Through the degassing tower, phosgene, hydrogen chloride, etc. are removed from the reaction liquid; then, through the solvent removal tower, the solvent in the reaction liquid is removed to obtain the crude NDI.

[0089] (3a) Separation process: The above-mentioned crude NDI is separated by using a short-path evaporator to remove the heavy components, obtaining an intermediate product and a primary heavy component.

[0090] (3b) Heavy component recovery process: The primary heavy component is recovered through a short-path evaporator to obtain a heavy component recovery material and a residual heavy component, which can be recovered once or in a cycle; the mixture obtained by mixing the heavy component recovery material and the intermediate product enters the refining process; the mass percentage content of the heavy component recovery material in the mixture is 1-10%.

[0091] (3c) Refining process: The above-mentioned mixture is continuously fed to the middle part of the distillation column; then, under the conditions of the aforementioned distillation (bottom temperature, top temperature, top pressure, bottom reflux ratio, top reflux ratio, residence time), the low-boiling substances are distilled off from the intermediate product, and the NDI composition is withdrawn from a position slightly below the middle of the column.

[0092] Thus, an NDI composition including NDI, CNI, and substances corresponding to the effective factors can be continuously manufactured.

[0093] In a third aspect, the present invention provides a modified composition of an isocyanate, and the modified composition is obtained by modifying an isocyanate composition as described in the first aspect; the modified composition contains any one or a combination of at least two of the groups (a)-(i): (a) isocyanurate group, (b) uretdione group, (c) biuret group, (d) carbamate group, (e) urea group, (f) iminooxadiazinedione group, (g) urethane group, (h) uretonimine group, (i) carbodiimide group.

[0094] Those skilled in the art can modify the aforementioned isocyanate composition according to needs by using known methods to obtain the modified composition; the modified composition is suitably used as a polyisocyanate component and a substance containing an active hydrogen group as a raw material for isocyanate-based polymers such as polyurethane resins.

[0095] Specifically, the modified composition containing the group (a) isocyanurate group is a trimer of isocyanate. Exemplarily, it can be obtained by reacting an isocyanate composition in the presence of a known isocyanuration catalyst to carry out isocyanuration of the isocyanate therein.

[0096] The modified composition containing the group (b) uretedione group can be obtained by heating the isocyanate composition at a temperature of 90 - 200 °C, or by reacting it in the presence of a known uretedionization catalyst to cause uretedionization (e.g., dimerization) of the isocyanate.

[0097] The modified composition containing the group (c) biuret group can be obtained by reacting the isocyanate composition with, for example, water, a tertiary alcohol (e.g., tert-butanol, etc.), a secondary amine (e.g., dimethylamine, diethylamine, etc.), etc., and then further reacting it in the presence of a known biuretization catalyst.

[0098] The modified composition containing the group (d) carbamate group can be obtained by reacting the isocyanate composition with a polyol (e.g., trimethylolpropane, etc.).

[0099] The modified composition containing the group (e) urea group can be obtained by reacting the isocyanate composition with water, a polyamine (described later), etc.

[0100] The modified composition containing the group (f) iminooxadiazinedione group is an asymmetric trimer of isocyanate and can be obtained by reacting the isocyanate composition in the presence of a known iminooxadiazinedionization catalyst to cause iminooxadiazinedionization (e.g., trimerization) of the isocyanate.

[0101] The modified composition containing the group (g) urethane group can be obtained by reacting the isocyanate composition with an alcohol and then further reacting it in the presence of a known urethanization catalyst.

[0102] The modified composition containing the group (h) uretonimine group can be obtained by reacting the isocyanate composition in the presence of a known carbodiimidization catalyst to form a carbodiimide group, and then adding an isocyanate to the carbodiimide group.

[0103] The modified composition containing the group (i) carbodiimide group can be obtained by reacting the isocyanate composition in the presence of a known carbodiimidization catalyst.

[0104] It should be noted that the modified composition only needs to contain at least one of the above groups (a) - (i), and it can also contain at least two. Such a modified composition can be generated by appropriately combining the above reactions. In addition, the modified composition can be used alone or in combination of two or more.

[0105] Fourth aspect, the present invention provides an isocyanate-based polymer, which is formed by reacting an isocyanate-based substance with a substance containing an active hydrogen group; the isocyanate-based substance includes at least one of the isocyanate composition as described in the first aspect and the modified composition as described in the third aspect.

[0106] Preferably, the active hydrogen group includes any one or a combination of at least two of hydroxyl group, amino group, and mercapto group.

[0107] Preferably, the substance containing an active hydrogen group includes any one or a combination of at least two of polyols, polyamines, and polythiols.

[0108] Among them, when the substance containing an active hydrogen group is a polyol, the isocyanate-based polymer is a polyurethane; when the substance containing an active hydrogen group is a polyamine, the isocyanate-based polymer is a polyurea; when the substance containing an active hydrogen group is a polythiol, the isocyanate-based polymer is a polythiourethane.

[0109] Fifth aspect, the present invention provides a polyurethane elastomer, and the raw materials for preparing the polyurethane elastomer include isocyanate-based substances and polyols; the isocyanate-based substances include the isocyanate composition as described in the first aspect and / or the modified composition as described in the third aspect.

[0110] Preferably, the polyol is a high molecular weight polyol.

[0111] Preferably, the raw materials for preparation further include a chain extender.

[0112] Preferably, the chain extender includes a low molecular weight polyol and / or a low molecular weight polyamine.

[0113] In the present invention, the polyurethane elastomer (PUR) can be a thermoplastic polyurethane elastomer (TPU), a thermosetting polyurethane elastomer (TSU), a rollable polyurethane elastomer, etc. The polyurethane elastomer contains soft segments formed by the reaction of an isocyanate-based substance with a polyol (high molecular weight polyol), and hard segments formed by the reaction of an isocyanate-based substance with a chain extender (low molecular weight polyol and / or low molecular weight polyamine). The polyurethane elastomer can be manufactured by the reaction of an isocyanate-based substance, a high molecular weight polyol (substance containing an active hydrogen group), a low molecular weight polyol and / or a low molecular weight polyamine (substance containing an active hydrogen group). That is, the isocyanate-based substance (the isocyanate composition and / or the modified composition), the polyol (high molecular weight polyol), and the chain extender (low molecular weight polyol and / or low molecular weight polyamine) are the raw materials for preparing the polyurethane elastomer.

[0114] In the present invention, the isocyanate-based substances include the isocyanate composition and / or the modified composition. The effective factor of the isocyanate composition is 3.80 - 5.30, and the modified composition is obtained by modifying the isocyanate composition with an effective factor of 3.80 - 5.30. Through the design and control of the effective factor, the present invention can effectively inhibit the discoloration of the polyurethane elastomer, improve the tensile strength and tear strength of the polyurethane elastomer, and enable the polyurethane elastomer to exhibit excellent comprehensive properties in terms of discoloration resistance, weather resistance, stability, and mechanical properties.

[0115] Preferably, the polyol is a high-molecular-weight polyol, and examples include, but are not limited to, any one or a combination of at least two of polyester polyol, polycarbonate polyol, and polyether polyol. Further preferably, it is a polyester polyol.

[0116] Preferably, the polyester polyol includes polycaprolactone polyol and / or adipic acid-based polyester polyol (a polyester polyol using adipic acid as the polybasic acid), and further preferably, it is an adipic acid-based polyester polyol.

[0117] Preferably, the polyether polyol includes polytetramethylene ether glycol.

[0118] Preferably, the chain extender includes a low-molecular-weight polyol and / or a low-molecular-weight polyamine, and further preferably, it is a low-molecular-weight polyol.

[0119] Preferably, the low-molecular-weight polyol includes ethylene glycol and / or 1,4-butanediol, and further preferably, it is 1,4-butanediol.

[0120] In the present invention, the polyurethane elastomer can be prepared by known methods such as the one-shot method or the prepolymer method.

[0121] For the one-shot method, for example, the isocyanate-based substances (polyisocyanate component, isocyanate composition and / or modified composition), polyol (high-molecular-weight polyol), and chain extender (low-molecular-weight polyol and / or low-molecular-weight polyamine) are reacted at once to obtain the polyurethane elastomer.

[0122] For the prepolymer method, for example, first, the isocyanate-based substances (polyisocyanate component, isocyanate composition and / or modified composition) are reacted with the polyol (high-molecular-weight polyol) to synthesize a prepolymer having an isocyanate group at the molecular end; then, the prepolymer is reacted with the chain extender (low-molecular-weight polyol and / or low-molecular-weight polyamine) to obtain the polyurethane elastomer.

[0123] It should be noted that regarding the preparation method of the polyurethane elastomer, polymerization methods known in the art can be adopted, such as bulk polymerization, solution polymerization, etc.

[0124] In addition, for the preparation of the polyurethane elastomer, if necessary, known urethanization catalysts such as amines, organometallic compounds (such as organotin compounds, preferably dibutyltin dichloride, tin octoate, etc.) can be added to the preparation raw materials.

[0125] Furthermore, if necessary, plasticizers, anti-caking agents, heat stabilizers, light stabilizers, ultraviolet absorbers, NOx yellowing inhibitors, antioxidants, mold release agents, pigments, dyes, lubricants, nucleating agents, fillers, hydrolysis inhibitors, etc. can be incorporated into the polyurethane elastomer in appropriate proportions.

[0126] As a preferred technical solution of the present invention, the polyurethane elastomer has excellent discoloration resistance and weather resistance, and excellent mechanical properties (tensile strength and tear strength).

[0127] In particular, the color difference Δb of the polyurethane elastomer after 240 h of damp heat aging test under xenon lamp irradiation is ≤3.0. For example, Δb can be 2.95, 2.9, 2.85, 2.8, 2.75, 2.7, 2.65, 2.6, 2.55, 2.5, 2.45, 2.4, 2.35, 2.3, 2.25, 2.2, 2.15, 2.1, 2.05, 2.0, 1.9, 1.8, 1.7, 1.6, 1.5, etc., and more preferably <3.0.

[0128] Preferably, the tensile strength of the polyurethane elastomer prepared from the NDI composition is >41 MPa, and can reach 41.3 - 42.5 MPa; the tear strength is >64 kN / m, and can reach 64.1 - 65.2 kN / m.

[0129] Preferably, the tensile strength of the polyurethane elastomer prepared from the PPDI composition is >44 MPa, and can reach 44.3 - 45.7 MPa; the tear strength is >119 kN / m, and can reach 119.6 - 121.6 kN / m.

[0130] Preferably, the tensile strength of the polyurethane elastomer prepared from the CHDI composition is >35 MPa, and can reach 35.1 - 36.1 MPa; the tear strength is ≥59 kN / m, and is 59.0 - 60.1 kN / m.

[0131] Compared with the prior art, the present invention has the following beneficial effects:

[0132] In the isocyanate composition provided by the present invention, through the design and control of effective factors, it has excellent reaction activity and can be used for the preparation of high-performance polyurethane products. The isocyanate composition can effectively improve the stability of polyurethane products, especially can significantly enhance the color change resistance and weather resistance of polyurethane elastomers, inhibit the increase of color number and yellowing under humid and hot conditions, make the color difference Δb of the polyurethane elastomer less than 3.0 after 240 h of damp heat aging test under xenon lamp irradiation, and improve the tensile strength and tear strength of the polyurethane elastomer, so that the polyurethane elastomer has excellent comprehensive performance in terms of weather resistance and mechanical strength, etc. Description of the Drawings

[0133] Figure 1 It is a schematic flow chart of the preparation method of the isocyanate composition in a specific embodiment of the present invention;

[0134] Among them, 10 - phosgenation process, 20 - removal process, 30 - separation process, 40 - heavy component recovery process, 50 - refining process. Specific Embodiments

[0135] The technical solutions of the present invention will be further described below through specific embodiments. Those skilled in the art should understand that the embodiments are only for helping to understand the present invention and should not be regarded as specific limitations to the present invention.

[0136] The testing methods for components and properties in the present invention are as follows:

[0137] 1. Determination of the mass content (B value) of chloro - isocyanate in the isocyanate composition: GCMS testing

[0138] Analysis is carried out by gas chromatography - mass spectrometry under the following conditions, and the content in this article is the normalized content.

[0139] Analysis instrument: Agilent 5977B GCMS

[0140] Chromatographic column: DB - 5 chromatographic column, with a specification of 30m×0.25mm×0.25μm

[0141] Column oven temperature: Maintain at 50°C for 2 min, increase the temperature to 80°C at a rate of 5°C / min, and then increase the temperature to 280°C at a rate of 15°C / min, and maintain for 10 min

[0142] Split ratio: Splitless

[0143] Injection port temperature: 280°C

[0144] Detection temperature: 300°C

[0145] Carrier gas: Helium

[0146] Carrier gas flow rate: 1 mL / min (constant flow rate)

[0147] Sample injection volume: 1 μL

[0148] Detection method: SIM selective ion scanning mode (selective ions 202 / 168 for NDI, 152 / 118 for PPDI, 158 / 124 for CHDI)

[0149] 2. Determination of the mass content (A value) of chlorine in the isocyanate composition: XRF test

[0150] Instrument: Energy dispersive X-ray fluorescence spectrometer (ED-XRF), model: MERAK-LE II;

[0151] Method: Standard addition method

[0152] Principle and operation: The chromatographically pure CCl4 standard is used as the Cl source, ethyl acetate is used as the diluent, the Cl element in the sample is excited by the X-ray generated by the X-ray tube to produce characteristic X-ray fluorescence, and the intensity of the characteristic X-ray fluorescence has a linear relationship with the element concentration. A standard curve is plotted, and the extrapolated value is the content of the Cl element in the sample.

[0153] 3. Determination of the mass percentage content of isocyanate in the isocyanate composition: Gas chromatography test

[0154] Analysis is carried out using gas chromatography under the following conditions, and the content in this article is the normalized content.

[0155] Analytical instrument: Agilent 7890B GC

[0156] Chromatographic column: DB-5 chromatographic column, specifications: 30 m × 0.25 mm × 0.25 μm

[0157] Column oven temperature: Hold at 60 °C for 1 min, then increase the temperature to 280 °C at a rate of 10 °C / min and hold for 5 min

[0158] Split ratio: 30:1

[0159] Injection port temperature: 280 °C

[0160] Detection temperature: 320 °C

[0161] Carrier gas: Nitrogen

[0162] Carrier gas flow rate: 1 mL / min (constant flow rate)

[0163] Sample injection volume: 1 μL

[0164] Detector: FID

[0165] In the following specific embodiments of the present invention, unless otherwise specified, "parts" and "%" are based on mass.

[0166] Example 1

[0167] An NDI composition and its preparation method, the effective factor E of the NDI composition is 5.30, and the flow schematic diagram of its preparation method is as Figure 1 shown, and specifically includes the following steps:

[0168] Phosgenation process: Charge 800 parts by mass of chlorobenzene into a cold reaction kettle, adjust the temperature in the cold reaction kettle to 20°C, and adjust the pressure (gauge pressure) to 0.04 MPaG. Continuously charge into the cold reaction kettle at a rate of 500 parts by mass / h an amine chlorobenzene solution with a concentration of 10.0 wt.% of 1,5-NDA (1,5-naphthalenediamine), and continuously introduce phosgene into the kettle at a rate of 626 parts by mass / h. The temperature of the cold reaction is 20°C, and the time is 2.5 h to obtain a cold reaction phosgenated liquid;

[0169] Take out the cold reaction phosgenated liquid from the cold reaction kettle and transfer it to a hot reaction kettle, and introduce phosgene into the hot reaction kettle at a rate of parts by mass / h. Maintain the temperature in the hot reaction kettle at 110°C, adjust the pressure (gauge pressure) to 0.2 MPa G, and carry out a hot reaction at a temperature of 110°C for 4 h. Thus, react 1,5-NDA with phosgene to generate 1,5-NDI, and prepare a reaction product containing 1,5-NDI.

[0170] Removal process: Continuously transfer the reaction product obtained in the phosgenation process to a phosgene removal tower and a solvent removal tower, and carry out phosgene removal treatment and solvent removal treatment respectively. Thus, 130 parts by mass of a crude product of NDI are prepared.

[0171] Separation process: Continuously transfer the crude product obtained in the removal process to a short-path evaporator to obtain 117.2 parts by mass of an intermediate product after removing heavy components and 12.8 parts by mass of a primary heavy component.

[0172] Heavy component recovery process: Continuously transfer the primary heavy component to a secondary short-path evaporator to obtain 2.39 parts by mass of a heavy component recovery material and 10.4 parts by mass of a residual heavy component. Next, mix the intermediate product at a rate of 117.2 parts by mass / h with the heavy component recovery material at a rate of 2.39 parts by mass / h to obtain a mixture at a rate of 119.6 parts by mass / h, that is, the mass percentage content of the heavy component recovery material in the mixture is 2%.

[0173] Purification process: Continuously transfer the aforementioned mixture to a distillation column. For the distillation column, it is filled with packing equivalent to 5 theoretical plates. Then, in the distillation column, remove light components from the top of the column and withdraw the NDI composition from the middle of the column to obtain the target product;

[0174] The rectification conditions in the rectification column are as follows:

[0175] Bottom temperature: 130 - 140 °C

[0176] Top temperature: 120 - 130 °C

[0177] Top pressure: 0 - 50 PaA

[0178] Residence time: 2 - 4 h

[0179] Top reflux ratio: 4

[0180] Thus, the NDI composition is obtained, wherein the mass content of NDI > 99%, the mass content of chlorine (A value) is 7.6 ppm, the mass content of chloro isocyanate CNI (B value) is 15 ppm, and the effective factor E is 5.30.

[0181] Examples 2 - 5, Comparative Examples 1 - 2

[0182] An NDI composition and its preparation method, the effective factor E of the NDI composition is shown in Table 1 respectively. The process flow of its preparation method is the same as that of Example 1, except that some process parameters are different, which are specifically shown in Table 1 (the processes / parameters not shown in Table 1 are exactly the same as those in Example 1). In Table 1, "phosgene molar ratio" represents the molar amount of phosgene in the phosgenation process based on 1 mol of 1,5 - NDA; "re - component recovery material ratio" represents the mass percentage of re - components (recovery materials) in the mixture in the re - component recovery process.

[0183] Table 1

[0184]

[0185]

[0186] Examples 6 - 10, Comparative Examples 3 - 4

[0187] A PPDI composition and its preparation method, the effective factor E of the PPDI composition is shown in Table 2 respectively. The process flow of its preparation method is the same as that of Example 1, except that some process parameters are different, which are specifically shown in Table 2 (the processes / parameters not shown in Table 2 are exactly the same as those in Example 1). In Table 2, "phosgene molar ratio" represents the molar amount of phosgene in the phosgenation process based on 1 mol of 1,4 - diaminobenzene; "re - component recovery material ratio" represents the mass percentage of re - components (recovery materials) in the mixture in the re - component recovery process.

[0188] Table 2

[0189]

[0190]

[0191] Examples 11 - 15, Comparative Examples 5 - 6

[0192] A CHDI composition and its preparation method. The effective factor E of the PPDI composition is shown in Table 3 respectively. The process flow of its preparation method is the same as that of Example 1, except that some process parameters are different, which are specifically shown in Table 3 (the processes / parameters not shown in Table 3 are exactly the same as those in Example 1). In Table 3, "phosgene molar ratio" represents the molar amount of phosgene in the phosgenation process based on 1 mol of 1,4 - diamino - cyclohexane; "re - component recovery material ratio" represents the mass percentage of the re - components (recovery materials) in the mixture in the re - component recovery process.

[0193] Table 3

[0194]

[0195]

[0196] Examples 16 - 18 and Comparative Examples 7 - 9

[0197] The method in Example 1 of the prior art CN110256296A was used to prepare NDI as Comparative Example 7. This example is a thermal cracking method to prepare NDI, and the product does not contain chlorine and thus does not contain the effective factor. The re - component recovery material in Example 1 was added to this product at a ratio of 4% (i.e., the mass percentage of the re - components in the obtained mixture is 4%) to obtain Example 16.

[0198] Similarly, using the method in Example 1 of CN110256296A, the raw material NDA was replaced with PPDA, and other conditions remained the same to prepare PPDI as Comparative Example 8. The re - component recovery material in Example 6 was added to this product at a ratio of 4% (i.e., the mass percentage of the re - components in the obtained mixture is 4%) to obtain Example 17.

[0199] Using the method in Example 1 of CN110256296A, the raw material NDA was replaced with CHDA, and other conditions remained the same to prepare CHDI as Comparative Example 9. The re - component recovery material in Example 11 was added to this product at a ratio of 4% (i.e., the mass percentage of the re - components in the obtained mixture is 4%) to obtain Example 18.

[0200] Application Examples

[0201] A polyurethane elastomer, specifically a thermoplastic polyurethane elastomer (TPU), the raw materials for its preparation include isocyanate substances (polyisocyanate components), high molecular weight polyols, and chain extenders (low molecular weight polyols); the isocyanate substances are respectively the isocyanate compositions provided in Examples 1-15 and Comparative Examples 1-6, the high molecular weight polyol is an adipic acid-based polyester polyol (manufactured by Mitsui Chemicals, TAKELAC U-2024, number average molecular weight of 2000), and the chain extender is 1,4-butanediol (Alfa Aesar reagent); in addition, the raw materials for the preparation also include a catalyst (tin octoate) and a heat stabilizer (purchased from Ciba Specialty Chemicals, IRGANOX 245).

[0202] The preparation method of the polyurethane elastomer is as follows:

[0203] (1) Charge 221 parts by mass of the NDI composition (168 parts by mass for the PPDI composition and 175 parts by mass for the CHDI composition) and 531.2 parts by mass of the adipic acid-based polyester polyol into a four-necked flask equipped with a stirrer, a thermometer, a reflux tube, and a nitrogen supply line. React at 80 °C under a nitrogen atmosphere until the NCO group content is 9.1 wt.%, to obtain a prepolymer with isocyanate groups at the molecular ends.

[0204] (2) Add 3.9 parts by mass of the heat stabilizer and 0.07 parts by mass of a solution obtained by diluting the catalyst tin octoate to 4 wt.% with diisononyl adipate (Alfa Aesar reagent) to the prepolymer obtained in step (1). Use a mechanical stirrer (IKA, Germany, RW20) to stir and mix at a rotation speed of 600 rpm for about 1 min, and then add 131.9 parts by mass of 1,4-butanediol that has been pre-adjusted to 80 °C to the system, and stir well for about 2 min until evenly mixed to obtain a mixed solution;

[0205] (3) Pour the mixed solution obtained in step (2) into a stainless steel tray that has been pre-adjusted to 150 °C, react at 150 °C for 1 h, and then react at 100 °C for 23 h to obtain an elastomer.

[0206] (4) Remove the elastomer obtained in step (3) from the tray and cure it for 7 days under constant temperature and humidity conditions of 23 °C at room temperature and 55% relative humidity to obtain the polyurethane elastomer.

[0207] Performance evaluation of the polyurethane elastomer:

[0208] Using an injection molding machine (model: NEX-140, Taifu Machinery), the polyurethane elastomer to be tested (raw material, the mixed solution obtained in step (2) of the application example) was injection molded under the settings of a screw rotation speed of 100 rpm and a barrel temperature of 150 - 235 °C, under the conditions of a mold temperature of 20 °C, an injection time of 10 s, an injection speed of 60 mm / s, and a cooling time of 45 s to obtain a sheet;

[0209] Under the constant temperature and humidity conditions of 23 °C and a relative humidity of 55%, the obtained sheet (with a thickness of 2 mm) was cured for 7 days to obtain a polyurethane elastomer sheet for testing, and the following performance tests were specifically carried out:

[0210] (1) First, use a color pigment meter to measure the b value (b1, initial value) of the polyurethane elastomer sheet; then conduct a xenon lamp irradiation test. Place the polyurethane elastomer sheet in a super xenon lamp climate test chamber (Weibang Instruments) at a temperature of 89 °C, a relative humidity of 50%, and a xenon lamp irradiance of 100 W / m 2 (the irradiation wavelength is 300 - 400 nm) and place it for 240 h. Then take out the sheet and measure the b value (b2) of the sheet by the same method as above. Calculate the color difference Δb of the polyurethane elastomer after 240 h of the damp heat aging test under xenon lamp irradiation, Δb = ∣b2 - b1∣;

[0211] (2) Tensile strength: The tensile strength of the elastomer was tested according to the method in GB / T 528 - 2009;

[0212] (3) Tear strength: The tear strength of the elastomer was tested according to the method in GB / T 529 - 2008;

[0213] The foregoing test results are shown in Tables 4, 5, and 6.

[0214] Table 4

[0215]

[0216] Table 5

[0217]

[0218]

[0219] Table 6

[0220]

[0221]

[0222] Combined with the above performance test data, it can be seen that by controlling the effective factor of the isocyanate composition within the range of 3.80 - 5.30, the polyurethane elastomer prepared based on the isocyanate composition has excellent stability and weather resistance. The color difference Δb < 3.0 after 240 h of damp heat aging treatment under xenon lamp irradiation, as low as 2.53 - 2.95, inhibiting the increase in color number and yellowing under damp heat conditions, and improving the tensile strength and tear strength of the polyurethane elastomer. Among them, the tensile strength of the polyurethane elastomer prepared from the NDI composition is 41.3 - 42.5 MPa, and the tear strength is 64.1 - 65.2 kN / m; the tensile strength of the polyurethane elastomer prepared from the PPDI composition is 44.3 - 45.7 MPa, and the tear strength is 119.6 - 121.6 kN / m; the tensile strength of the polyurethane elastomer prepared from the CHDI composition is 35.1 - 36.1 MPa, and the tear strength is 59.0 - 60.1 kN / m, enabling the polyurethane elastomer to maintain excellent comprehensive product properties such as appearance, weather resistance, and mechanical properties. Thus, it can be seen that the isocyanate composition provided by the present invention has a better application prospect in polyurethane elastomers.

[0223] The applicant declares that the present invention uses the above embodiments to illustrate the isocyanate composition, modified composition, and polyurethane elastomer of the present invention, but the present invention is not limited to the above process steps, that is, it does not mean that the present invention must rely on the above process steps to be implemented. Those skilled in the art should understand that any improvement to the present invention, equivalent replacement of the raw materials selected for the present invention, addition of auxiliary components, and selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. An isocyanate composition, characterized in that, The effective factor of the isocyanate composition is 3.80 - 5.30; The calculation formula of the effective factor is as shown in Formula I: where E is the effective factor; A is the mass content of chlorine in the isocyanate composition; B is the mass content of chloro-isocyanate in the isocyanate composition; M Cl is the relative atomic mass of chlorine; M B is the relative molecular mass of the chloro isocyanate; The mass content of chlorine in the isocyanate composition is 1 - 1000 ppm; The mass content of chloro-isocyanate in the isocyanate composition is 5 - 2000 ppm; A is obtained by X-ray fluorescence spectrometry; B is obtained by gas chromatography-mass spectrometry; The isocyanate composition includes a combination of an isocyanate and a chlorine-containing substance; The chlorine-containing substance includes a combination of chloro-isocyanate and a substance corresponding to the effective factor; The isocyanate is any one of naphthalene diisocyanate, benzene diisocyanate, cyclohexane diisocyanate, toluene diisocyanate, diphenylmethane diisocyanate; The chloro-isocyanate is a compound obtained by replacing one NCO group in the isocyanate with chlorine; The substance corresponding to the effective factor includes any one or a combination of at least two of the following compounds: wherein R is a divalent group obtained by removing the NCO group from the isocyanate.

2. The isocyanate composition according to claim 1, characterized in that, The mass percentage content of the isocyanate in the isocyanate composition is ≥97%; 3. The isocyanate composition according to claim 1, characterized in that, The chloro-isocyanate is Any one of them.

4. The isocyanate composition according to claim 1, characterized in that, R is selected from any one of them; wherein, the wavy line represents the connection site of the group.

5. The isocyanate composition according to claim 1, characterized in that, B is obtained by gas chromatography-mass spectrometry.

6. A method for preparing an isocyanate composition according to any one of claims 1-5, characterized in that, The preparation method includes: reacting an amine compound with phosgene to obtain the isocyanate composition.

7. The preparation method according to claim 6, wherein The preparation method includes the following steps: (1) Reacting an amine compound with phosgene to obtain a reaction product; (2) Performing a removal treatment on the reaction product obtained in step (1) to obtain a crude product; the removal treatment includes phosgene removal treatment and / or solvent removal treatment; (3) Separating and refining the crude product obtained in step (2) in sequence to obtain the isocyanate composition.

8. The preparation method according to claim 7, characterized in that, In step (3), the separation obtains a heavy fraction and an intermediate product; the separated heavy fraction is a primary heavy fraction, and the primary heavy fraction is separated again to obtain a heavy fraction recycle and a residual heavy fraction; the heavy fraction recycle is mixed with the intermediate product to obtain the mixture; the mass percentage content of the heavy fraction recycle in the mixture is 1 - 10%, and the mixture of the intermediate product and the heavy fraction is refined to obtain the isocyanate composition.

9. The preparation method according to claim 7, wherein The refining method is distillation.

10. A modified composition of isocyanate, characterized in that, The modified composition is obtained by modifying with the isocyanate composition according to any one of claims 1 - 5; The modified composition contains any one or a combination of at least two of the groups (a)-(i): (a) isocyanurate group, (b) uretdione group, (c) biuret group, (d) carbamate group, (e) urea group, (f) iminooxadiazinedione group, (g) urethane group, (h) uretonimine group, (i) carbodiimide group.

11. An isocyanate group-containing polymer, characterized in that, The isocyanate-based polymer is formed by reacting an isocyanate substance with a substance containing an active hydrogen group; the isocyanate substance includes at least one of the isocyanate composition according to any one of claims 1 - 5 and the modified composition according to claim 10.

12. A polyurethane elastomer, characterized in that, The raw materials for preparing the polyurethane elastomer include isocyanate substances and polyols; the isocyanate substances include the isocyanate composition as described in any one of claims 1-5 and / or the modified composition as described in claim 10.

13. The polyurethane elastomer according to claim 12, characterized in that, The raw materials for preparation further include a chain extender.

14. The polyurethane elastomer according to claim 13, characterized in that, The chain extender includes low molecular weight polyols and / or low molecular weight polyamines.

Images