An isocyanate composition, a preparation method thereof, and applications thereof

Abstract

The present invention provides an isocyanate composition, a preparation method and an application thereof. The effective factor of the isocyanate composition is 3.70 - 4.70. 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 effectively improve the stability of polyurethane products, especially endow the polyurethane coating material with excellent colorfastness performance, maintain excellent color stability in high-temperature and high-humidity environments, and the color difference Δb of the coating is ≤ 1.2 after 2000 h of damp heat durability test, significantly improving the yellowing resistance and appearance of the coating.

Description

Technical Field

[0001] The present invention belongs to the technical field of isocyanates, and particularly relates to an isocyanate composition, a preparation method thereof and an application thereof. Background Art

[0002] Polyurethane coatings have superior properties such as low film-forming temperature, strong adhesion, good abrasion resistance, high hardness, good chemical resistance and good weather resistance, and are widely used in industrial protective paints, wood furniture paints, automotive original paints and automotive refinish paints. Polyurethane coatings usually consist of isocyanates and polyols. Compared with aromatic isocyanates, aliphatic isocyanates have relatively excellent stability and are more commonly used raw materials in polyurethane coatings. Aliphatic isocyanates can be classified into straight-chain aliphatic isocyanates and cyclic aliphatic isocyanates according to their molecular structures. Typical examples of the former include hexamethylene diisocyanate (HDI), etc., and the latter are also called alicyclic isocyanates, and typical examples include dicyclohexylmethane diisocyanate (HMDI), isophorone diisocyanate (IPDI), etc.

[0003] Although aliphatic isocyanates such as HDI, HMDI, IPDI, etc. have various advantages, they also have the following deficiencies: due to the presence of trace impurities in the synthesis process, the color of the isocyanate is relatively dark, and side reactions will occur during subsequent modification processes, resulting in insufficient colorfastness of products such as polyurethane coatings prepared.

[0004] Isocyanates can be prepared by the reaction of the corresponding amines with phosgene (carbonyl chloride). In order to make up for the deficiencies of isocyanates, researchers start from the preparation of isocyanates and improve the properties of the products by controlling the raw materials. For example, CN101440046A discloses the preparation of light-colored isocyanates, which is carried out by reacting the corresponding amines with phosgene in the presence or absence of an inert medium. The amine stream fed into the phosgenation reaction has an average PRI value lower than 60 moles per million moles (mpm), and PRI represents the impurities reducible by polarography. In this preparation method, HDI is prepared by controlling the polarographic value PRI of hexamethylenediamine, and then a polymerization reaction is carried out to obtain an HDI trimer with a low color number. CN103319372A discloses a method for preparing light-colored or colorless dicyclohexylmethane diisocyanate, which includes: a) purifying the raw material dicyclohexylmethane diamine to obtain dicyclohexylmethane diamine containing less than 0.2 wt% of alcohol compounds; b) subjecting the dicyclohexylmethane diamine containing less than 0.2 wt% of alcohol compounds to phosgenation to obtain dicyclohexylmethane diisocyanate, and the dicyclohexylmethane diisocyanate obtained by this method has the characteristics of light color or colorlessness. CN1356980A discloses light-colored isocyanates, their preparation methods and uses, which use phosgene containing less than 50 ppm of bromine or iodine or a mixture thereof in molecular or bound form as a raw material and react with amines to prepare isocyanates. The preparation of light-colored isocyanates is achieved by controlling the contents of bromides and iodides in phosgene, so that the isocyanates have a lower iodine color value IFZ. CN109761855A discloses a method for preparing isophorone diisocyanate, and the steps are as follows: isophorone reacts with hydrogen cyanide to obtain isophorone nitrile; isophorone nitrile, ammonia and hydrogen react in the presence of a catalyst to obtain isophorone diamine; the isophorone diamine is subjected to phosgenation reaction to obtain isophorone diisocyanate; wherein, the content of impurities containing secondary amino groups in the isophorone diamine subjected to phosgenation reaction is ≤0.5 wt%. This method effectively reduces the hydrolysis chlorine content and the chromaticity of the isophorone diisocyanate product.

[0005] In the preparation methods of isocyanates disclosed in the prior art, by controlling the polarographic value of amines, the content of alcohol impurities in amines, the content of secondary amino group impurities in amines, the content of impurities in phosgene, etc., the improvement of the color of isocyanates is achieved to a certain extent. However, in the subsequent modification and the production of polyurethane products, the light-colored isocyanates will show a phenomenon of color deepening, and the obtained polyurethane products have relatively serious weather resistance problems. Obvious yellowing will occur after long-term use, thus affecting the appearance and service performance of polyurethane products, especially polyurethane coatings and coatings.

[0006] Therefore, developing isocyanates with excellent properties to improve the color change resistance of polyurethane products, especially polyurethane coatings and coatings, is the research focus in this field. Summary of the Invention

[0007] Aiming at the deficiencies of the prior art, the purpose of the present invention is to provide an isocyanate composition, a preparation method and an application thereof. Through the design and control of effective factors, the isocyanate composition can be used to prepare high-performance polyurethane products, and significantly improve the color fastness of polyurethane products, especially polyurethane coating materials and coatings.

[0008] To achieve the purpose of this invention, the following technical solutions are adopted:

[0009] In the first aspect, the present invention provides an isocyanate composition, and the effective factor of the isocyanate composition is 3.70 - 4.70.

[0010] The calculation formula of the effective factor is shown in Formula I:

[0011]

[0012] In Formula I, E is the effective factor;

[0013] In Formula I, A is the mass content of chlorine in the isocyanate composition.

[0014] In Formula I, B is the mass content of chloro-isocyanate in the isocyanate composition.

[0015] In Formula I, M Cl is the relative atomic mass of chlorine.

[0016] In Formula I, M B is the relative molecular mass of the chloro-isocyanate.

[0017] The effective factor E of the isocyanate composition provided by the present invention is 3.70 - 4.70, and can be, for example, 3.75, 3.80, 3.85, 3.90, 3.95, 4.00, 4.05, 4.10, 4.15, 4.20, 4.25, 4.30, 4.35, 4.40, 4.45, 4.50, 4.55, 4.60 or 4.65, 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 above range.

[0018] In the present invention, the isocyanate composition includes a combination of an isocyanate and a chlorine-containing substance, so it is defined as a "composition"; the chlorine-containing substance includes a combination of a chloro isocyanate and a substance corresponding to an effective factor. Through the design and control of the effective factor, the isocyanate composition in the present invention includes a specific type of chlorine-containing substance with a specific content, making it have excellent reactivity and capable of being used in the preparation of high-performance polyurethane products. The isocyanate composition can effectively improve the color fastness and stability of polyurethane products. In particular, the polyurethane coating material has excellent color fastness and maintains excellent color stability in high-temperature and high-humidity environments, significantly improving the yellowing resistance and appearance of the coating. If the effective factor of the isocyanate composition is too high or too low, the color fastness of the polyurethane coating material will decrease, and obvious yellowing will occur in the coating under high-temperature and high-humidity conditions.

[0019] In the present invention, in formula I for calculating the effective factor, A is the mass content of chlorine in the isocyanate composition, and A is obtained by testing with X-ray fluorescence spectrometry (XRF).

[0020] In the present invention, in formula I for calculating the effective factor, B is the mass content of chloro isocyanate in the isocyanate composition, preferably obtained by chromatography-mass spectrometry, and more preferably obtained by gas chromatography-mass spectrometry (GCMS).

[0021] In the research of the present invention, it is found that the methods for characterizing the chlorine content in isocyanates disclosed in the prior art cannot accurately control the performance of isocyanates, and thus cannot effectively control the quality of polyurethane products, especially the color fastness of polyurethane coating materials. Specifically, the test method for the total chlorine content in Standard GB / T 12009.1-1989 is the oxygen flask combustion method. All chlorine (including bromine) in the isocyanate is converted into inorganic chlorine (including bromine) and then titrated with silver nitrate, which characterizes all the chlorine content in the isocyanate, including the bromine content. Standard GB / T 12009.2-2016 measures hydrolyzable chlorine, specifically the chlorine released after the reaction of the isocyanate with alcohol and water, which is the more reactive chlorine in the isocyanate and also includes the more reactive bromine. Some monochloro isocyanates can also hydrolyze a part. The chlorine (including a part of bromine) content measured by GB / T 12009.1-1989 or GB / T 12009.2-2016 cannot accurately represent the component information of the isocyanate, and thus cannot effectively control the performance of the isocyanate and polyurethane products.

[0022] 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 chlorinated isocyanates obtained by chromatographic mass spectrometry test. The values of A and B are obtained by accurate qualitative and quantitative analysis methods, so that the effective factor E accurately characterizes the polychlorinated compounds and partial hydrolyzed chlorine (excluding the hydrolyzed chlorine of monochlorinated isocyanates) 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 isocyanates and the performance of polyurethane products (polyurethane coating materials), thus realizing the performance regulation of the isocyanate composition, and further effectively improving the performance of polyurethane products prepared therefrom. In particular, it has a significant improvement effect on the color fastness performance of polyurethane coating materials.

[0023] Preferably, the isocyanate is a diisocyanate, and further preferably an aliphatic diisocyanate, including a linear aliphatic diisocyanate and / or a cyclic aliphatic diisocyanate (alicyclic diisocyanate).

[0024] Preferably, the isocyanate includes any one or a combination of at least two of pentamethylene diisocyanate (PDI), hexamethylene diisocyanate (HDI), dicyclohexylmethane diisocyanate (HMDI), and isophorone diisocyanate (IPDI).

[0025] In the present invention, unless otherwise specified, the listed isocyanates include all their isomers. For example, the dicyclohexylmethane diisocyanate (HMDI) is

[0026] 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., and further preferably ≥99%.

[0027] Preferably, the substances corresponding to the effective factor include 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, R is selected from a C6 linear or branched alkylene group (for example the isocyanate is HDI), a C5 linear or branched alkylene group (for example the isocyanate is PDI), (the isocyanate is HMDI), Any one or a combination of at least two of them (the isocyanate is IPDI); wherein, the wavy line represents the bonding site of the group.

[0029] Preferably, the chloro isocyanate is a compound obtained by substituting one NCO group in the isocyanate with chlorine.

[0030] Preferably, the chloro isocyanate includes OCN-R 1 -CI (chlorohexyl isocyanate CHI, the isocyanate is HDI), OCN-R 2 -CI (chloropentyl isocyanate CPI, the isocyanate is PDI), (chlorodicyclohexylmethane diisocyanate CHMI, the isocyanate is HMDI), (chloroisophorone diisocyanate CIPI, the isocyanate is IPDI) in any one or a combination of at least two of them; wherein, R 1 is a C6 straight-chain or branched-chain alkylene group (for example ), R 2 is a C5 straight-chain or branched-chain alkylene group (for example ).

[0031] Preferably, the chloro isocyanate includes in any one or a combination of at least two of them.

[0032] In this article, the expression of the ring structure crossed by "-" indicates that the bonding site is at any position on the ring structure where bonding can occur.

[0033] Preferably, the mass content of chlorine (A value) in the isocyanate composition is 2 - 1000 ppm, for example, it can be 5 ppm, 10 ppm, 50 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 present invention does not exhaustively list the specific point values included in the above range. More preferably, it is 20 - 900 ppm.

[0034] Preferably, the mass content (B value) of chlorinated isocyanate in the isocyanate composition is 5 - 3000 ppm, and can be, for example, 20 ppm, 50 ppm, 100 ppm, 300 ppm, 500 ppm, 700 ppm, 900 ppm, 1000 ppm, 1100 ppm, 1300 ppm, 1500 ppm, 1700 ppm, 1900 ppm, 2000 ppm, 2100 ppm, 2300 ppm, 2500 ppm, 2700 ppm or 2900 ppm, as well as specific point values between the above point values. Due to space limitations and for the sake of brevity, the specific point values included in the scope of the present invention are not exhaustively listed herein.

[0035] In the present invention, "ppm" is parts per million ratio, and 1 ppm represents one millionth; when the same expression is involved hereinafter, it shall have the same meaning.

[0036] It should be noted that in the present invention, the substances corresponding to the effective factor, chlorinated isocyanate, can be produced as by-products during the preparation of isocyanate, or can be added artificially to obtain the required content.

[0037] In the second aspect, the present invention provides a method for preparing an isocyanate composition as described in the first aspect, and the preparation method includes: reacting an amine compound with phosgene to obtain the isocyanate composition.

[0038] Preferably, the preparation method includes the following steps:

[0039] (1) Reacting an amine compound with phosgene to obtain a reaction product;

[0040] (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;

[0041] (3) Separating and refining the crude product obtained in step (2) in sequence to obtain the isocyanate composition.

[0042] Preferably, in step (3), the separation obtains a heavy fraction and an intermediate product; refining the mixture of the intermediate product and the heavy fraction to obtain the isocyanate composition; the mass percentage content of the heavy fraction in the mixture is 1 - 10%.

[0043] As a preferred technical solution of the present invention, the component to be refined is a mixture of the intermediate and a heavy component, and the mass percentage of the heavy component in the mixture is 1-10%, for example, it can be 2%, 3%, 4%, 5%, 6%, 7%, 8% or 9%, and specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range, and 2-10% is further preferred.

[0044] Preferably, the separated heavy component can be directly mixed with the intermediate product to obtain a mixture; or, the separated heavy component is a primary heavy component, and the primary heavy component is separated again to obtain a heavy component recovery material and a residual heavy component; the heavy component recovery material is mixed with the intermediate product to obtain the mixture; the mass percentage of the heavy component recovery material in the mixture is 1-10%.

[0045] In another preferred technical solution, the preparation method of the isocyanate composition comprises: mixing the isocyanate obtained by the carbamate cleavage method with the heavy component recovery material to obtain the isocyanate composition. Preferably, the mass percentage of the heavy component recovery material in the isocyanate composition is 1-10% (e.g., 2%, 3%, 4%, 5%, 6%, 7%, 8% or 9%, etc.), and more preferably 1-5%.

[0046] As a preferred technical solution of the present invention, the preparation method of the isocyanate composition is a 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 (for example, a diamine hydrochloride obtained by reacting a diamine with HCl).

[0047] Preferably, the method for reacting the amine compound with phosgene illustratively includes the following three categories: a method in which a diamine reacts with phosgene in a gas phase, also known as a gas phase phosgenation method; a method in which a diamine reacts with phosgene in a liquid phase, also known as a liquid phase phosgenation method; a method in which a diamine salt (such as diamine hydrochloride) reacts with phosgene in a solvent, also known as a diamine hydrochloride phosgenation method, and the gas phase phosgenation method is further preferred.

[0048] Preferably, the reaction in step (1) is carried out in a reaction zone with or without an inert medium.

[0049] Preferably, the reaction in step (1) is carried out in the gas phase, that is, the gas phase phosgenation method, the vaporization of the amine compound (diamine) is carried out in advance, and the obtained gas phase diamine has no droplets before entering the reaction zone.

[0050] Preferably, the reaction in step (1) can be carried out in a batch operation, a semi-continuous operation or a continuous operation, and more preferably in a continuous operation.

[0051] Preferably, the inert medium is selected from any one or a combination of at least two of nitrogen, noble gases (such as argon and / or helium), aromatic compounds (such as chlorobenzene, dichlorobenzene, toluene, xylene), carbon monoxide, carbon dioxide, etc., and is further preferably any one or a combination of at least two of nitrogen, chlorobenzene or dichlorobenzene.

[0052] Preferably, the amount of the inert medium is calculated by the gas volume of the vaporized inert medium, and the volume ratio of the inert medium (gas) to the diamine (gas) is (0.01 - 5):1. For example, it can be 0.02:1, 0.05:1, 0.08:1, 0.1:1, 0.3:1, 0.5:1, 0.8:1, 1:1, 1.5:1, 2:1, 2.5:1, 3:1, 3.5:1, 4:1 or 4.5:1, etc. It is further preferably (0.05 - 3):1, and more preferably (0.1 - 1):1.

[0053] Preferably, the specific method of the reaction in step (1) includes: reacting the vaporized diamine with phosgene in a reaction zone to obtain a reaction product.

[0054] Preferably, the molar ratio of the phosgene to the amine compound (diamine) is (2.5 - 20):1. For example, it can be 3:1, 5:1, 7:1, 9:1, 10:1, 11:1, 13:1, 15:1, 17:1 or 19:1, etc. It is preferably (4 - 10):1, and more preferably (6 - 10):1.

[0055] Preferably, the temperature of the reaction in step (1) is 300 - 500 °C. For example, it can be 310 °C, 330 °C, 350 °C, 370 °C, 390 °C, 400 °C, 410 °C, 430 °C, 450 °C, 470 °C or 490 °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 above range. It is further preferably 350 - 450 °C.

[0056] Preferably, the absolute pressure of the reaction in step (1) is 0.05 - 0.3 MPa. For example, it can be 0.06 MPa, 0.08 MPa, 0.1 MPa, 0.12 MPa, 0.15 MPa, 0.18 MPa, 0.2 MPa, 0.22 MPa, 0.25 MPa or 0.28 MPa, 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. It is further preferably 0.07 - 0.2 MPa, and even more preferably 0.09 - 0.18 MPa.

[0057] Preferably, the flow rates of the vaporized diamine and phosgene feed streams entering the reaction zone are each independently 5-100 m / s, for example, they can be 10 m / s, 15 m / s, 20 m / s, 25 m / s, 30 m / s, 35 m / s, 40 m / s, 45 m / s, 50 m / s, 55 m / s, 60 m / s, 65 m / s, 70 m / s, 75 m / s, 80 m / s, 85 m / s, 90 m / s or 95 m / s, 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 10-80 m / s.

[0058] Preferably, the average contact time of the amine compound (diamine) and phosgene in the reaction zone is 0.01-15 s, for example, it can be 0.02 s, 0.05 s, 0.08 s, 0.1 s, 0.3 s, 0.5 s, 0.8 s, 1 s, 2 s, 3 s, 4 s, 5 s, 6 s, 7 s, 8 s, 9 s, 10 s, 11 s, 12 s, 13 s or 14 s, 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 0.04-10 s, and more preferably 0.08-5 s.

[0059] Preferably, the product of the reaction of the amine compound (diamine) and phosgene in step (1) is spray-washed (trapped) with an inert solvent in a single stage or multiple stages to lower the temperature of the product to ≤150 °C, obtaining the reaction product (reaction liquid containing isocyanate).

[0060] Preferably, the inert solvent is an organic solvent, exemplarily including but not limited to: aromatic hydrocarbons such as benzene, toluene, xylene, etc.; aliphatic hydrocarbons such as octane, decane, etc.; cycloaliphatic hydrocarbons such as cyclohexane, methylcyclohexane, ethylcyclohexane, etc.; halogenated aromatic hydrocarbons such as chlorotoluene, chlorobenzene, dichlorobenzene, dibromobenzene, trichlorobenzene, etc.; nitrogen-containing compound classes such as nitrobenzene, N,N-dimethylformamide, N,N-dimethylacetamide, N,N'-dimethylimidazolinone, etc.; ethers such as dibutyl ether, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, etc.; ketones such as heptanone, diisobutyl ketone, methyl isobutyl ketone, methyl ethyl ketone, etc.; fatty acid esters such as ethyl acetate, butyl acetate, amyl acetate, ethoxyethyl acetate, etc.; aromatic carboxylic acid esters such as methyl salicylate, dimethyl phthalate, dibutyl phthalate, methyl benzoate, etc.; The inert solvent can be used alone or as a combination of at least two.

[0061] Preferably, the inert solvent includes halogenated aromatic hydrocarbons, and further preferably chlorobenzene and / or dichlorobenzene.

[0062] The reaction product obtained in step (1) may be subjected to a removal step (a desolvation step and / or a phosgene removal step) and a separation and purification step as necessary.

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

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

[0065] Preferably, the separation in step (3) separates the intermediate product (light component) from the heavy component to remove the heavy component; the separation device illustratively includes but is not limited to: a short-path evaporator and a distillation tower.

[0066] Preferably, the operating pressure of the short-path evaporator is 0.05-4 kPa, for example, it may 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 specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range, and it is further preferably 0.1-2.5 kPa.

[0067] As a preferred technical solution of the present invention, the separated heavy component contains chlorine-containing substances with relatively rich types and high contents. By adding the heavy component or the heavy component recovery material obtained by re-separating the heavy component into the separated intermediate product (light component) in a certain proportion and then refining it, the types and contents of chlorine-containing substances in the product can be effectively regulated, so that the effective factor of the isocyanate composition is 3.90-5.70.

[0068] Preferably, the mass percentage of the heavy component (heavy component recycling material) in the mixture (material involved in the refining) is 1-10%, and more preferably 2-10%, so that the effective factor of the isocyanate composition is 3.70-4.70. If the amount of the heavy component (heavy component recycling material) added is too little, the effective factor is too high, and the isocyanate composition is used to prepare polyurethane products, which will lead to too fast reaction rate and poor color change resistance; if the amount of the heavy component (heavy component recycling material) added is too high, resulting in a low effective factor, the isocyanate composition contains more impurities, which will also affect the color change resistance and stability of the polyurethane product, resulting in obvious yellowing of the polyurethane coating material in a hot and humid environment.

[0069] Preferably, the heavy components mixed with the intermediate product can be directly re-incorporated into the intermediate product, or the heavy components can be obtained as a recycled heavy component recovery material after being separated by a heavy component removal device and then incorporated into the intermediate product.

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

[0071] Preferably, the refining method in step (3) 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 rectification column is 2 - 60, for example, it can be 3, 5, 8, 10, 12, 15, 18, 20, 22, 25, 28, 30, 32, 35, 38, 40, 42, 45, 48, 52, 52, 55 or 58, 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 - 40.

[0074] Preferably, the top pressure of the rectification 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 rectification column is 0.01 - 60, 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, 38, 40, 42, 45, 48, 50, 52, 55 or 58, 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 - 40.

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

[0077] (1) Phosgenation process: The vaporized diamine reacts with phosgene, and the resulting product is spray-washed (trapped) with an inert solvent to obtain a reaction product;

[0078] (2) Removal process: 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;

[0079] (3a) Separation process: The crude product obtained in step (2) is separated to obtain a heavy fraction and an intermediate product (light fraction);

[0080] (3b) Heavy fraction recovery process: The intermediate product and the heavy fraction obtained in step (3a) are mixed to obtain a mixture; the mass percentage content of the heavy fraction in the mixture is 1-10%; or, the heavy fraction obtained in step (3a) is subjected to secondary separation 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 a mixture; the mass percentage content of the heavy fraction recovery material in the mixture is 1-10%;

[0081] (3c) Refining process: The mixture obtained in step (3b) is refined 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 heavy fraction recovery process 40, and a refining process 50. Among them, the phosgenation process can be implemented in an intermittent manner or a continuous manner. By appropriately adjusting the mixing ratio of the heavy fraction and the intermediate product, the supply ratio of phosgene, the reaction temperature, 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 mixing ratio of the heavy fraction and the intermediate product.

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

[0084] (1) Phosgenation process: Using a tubular reactor, the vaporized 1,6-hexanediamine is mixed with optionally nitrogen and then reacted continuously with phosgene in the tubular reactor. After the generated product leaves the reaction zone, it is continuously spray-washed (trapped) with chlorobenzene to obtain a reaction product, that is, a reaction liquid containing isocyanate.

[0085] Thus, the phosgenation process is continuously implemented.

[0086] Thus, the salt formation process and the phosgenation process are continuously implemented.

[0087] (2) Removal process: It is carried out using a phosgene removal tower and a solvent removal tower. The above-mentioned reaction liquid is continuously fed to the middle part of the phosgene removal tower. Through the phosgene removal tower, phosgene, hydrogen chloride, etc. in the reaction liquid are removed; then through the solvent removal tower, the solvent in the reaction liquid is removed to obtain a crude HDI product.

[0088] (3a) Separation process: The above-mentioned crude HDI is separated using a short-path evaporator to remove the heavy components, obtaining an intermediate product and a primary heavy component.

[0089] (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 secondary heavy component, which can be recovered either singly or in a cycle; the mixture obtained by mixing the heavy component recovery material with the intermediate product enters the refining process; the mass percentage of the heavy component recovery material in the mixture is 1-10%.

[0090] (3c) Refining process: Continuously feed the above-mentioned mixture into the middle 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 components are distilled off from the intermediate product, and the HDI composition is withdrawn from a position slightly below the middle of the column.

[0091] Thus, an HDI composition including HDI, CHI, and substances corresponding to the effective factors can be continuously manufactured.

[0092] In a third aspect, the present invention provides a modified isocyanate composition, which is obtained by modifying the isocyanate composition as described in the first aspect.

[0093] The modified isocyanate 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 as needed using known methods to obtain the modified isocyanate composition; the modified isocyanate composition is suitably used as a raw material for polyurethane and other polymers with an isocyanate substance (polyisocyanate component) and a substance containing an active hydrogen group.

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

[0096] The modified isocyanate composition containing the group (b) uretdione group can be obtained by heating the isocyanate composition at 90-200 °C or by reacting it in the presence of a known uretdionization catalyst to cause uretdionization (such as dimerization) of the isocyanate.

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

[0098] The modified isocyanate composition containing the group (d) urethane group can be obtained by reacting an isocyanate composition with a polyol component (such as trimethylolpropane, etc.).

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

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

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

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

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

[0105] Taking the HDI composition as an example, those skilled in the art can modify the HDI composition according to needs by known methods to obtain a modified HDI composition. The modified HDI composition is suitably used as an isocyanate substance (polyisocyanate component) and a substance containing an active hydrogen group as a raw material for polyurethane.

[0106] Fourth aspect, the present invention provides a polymer based on isocyanate, which 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 as described in the first aspect and the modified isocyanate composition as described in the third aspect.

[0107] Preferably, the active hydrogen group includes any one or a combination of at least two of a hydroxyl group, an amino group, and a mercapto group.

[0108] Preferably, the substance containing an active hydrogen group includes any one or a combination of at least two of a polyol, a polyamine, and a polythiol.

[0109] Wherein, when the substance containing an active hydrogen group is a polyol, the polymer is a polyurethane; when the substance containing an active hydrogen group is a polyamine, the polymer is a polyurea; when the substance containing an active hydrogen group is a polythiol, the polymer is a polythiourethane.

[0110] Fifth aspect, the present invention provides a two-component polyurethane composition, which includes component A and component B; component A includes the isocyanate composition as described in the first aspect and / or the modified isocyanate composition as described in the third aspect; component B includes a substance containing an active hydrogen group.

[0111] Regarding the two-component polyurethane composition in which the isocyanate substance including the isocyanate composition and / or the modified isocyanate composition is used as component A and the substance containing an active hydrogen group is used as component B, it can be applied to coating raw materials such as coatings and adhesives, two-component curable sealing raw materials, potting agents, etc. Such a two-component polyurethane composition is a raw material in which component A (curing agent) and component B (main agent) separately prepared are mixed immediately before use.

[0112] The coating raw material is a two-component curable resin raw material for forming a coating, and includes component A (curing agent) and component B (main agent). The coating can include coatings, adhesives, etc.

[0113] When using the coating raw material as a coating, exemplary uses include but are not limited to: coatings for plastics, coatings for automotive exterior decoration, coatings for automotive interior decoration, coatings for electrical / electronic materials, coatings for optical materials (such as lenses), coatings for building materials, glass coating paints, woodworking paints, film coating paints, ink paints, coatings for artificial leather (coating agents), coatings for cans (coating agents), etc.

[0114] Preferably, component A includes a modified isocyanate composition, which is obtained by modifying the isocyanate composition and preferably contains group (a) isocyanurate group and / or group (d) urethane group.

[0115] In addition, according to requirements, the Agent A may further contain other aromatic isocyanates, aliphatic isocyanates, and araliphatic isocyanates.

[0116] In the present invention, the Agent A in the two-component polyurethane composition includes the isocyanate composition and / or the modified isocyanate composition; the effective factor of the isocyanate composition is 3.70 - 4.70, and the modified isocyanate composition is obtained by modifying the isocyanate composition with an effective factor of 3.70 - 4.70. Through the design and control of the effective factor, as a two-component polyurethane coating, the two-component polyurethane composition can effectively inhibit the discoloration of the coating, keep the coating excellent in stability under high-temperature and high-humidity environments, and significantly improve the discoloration resistance of the coating.

[0117] Preferably, the active hydrogen groups in the Agent B include any one or a combination of at least two of hydroxyl groups, amino groups, and mercapto groups (thiol groups).

[0118] Preferably, the Agent B includes any one or a combination of at least two of polyols (components containing at least 2 hydroxyl groups), polythiols (components containing at least 2 mercapto / thiol groups), and polyamines (components containing at least 2 amino groups).

[0119] Preferably, the Agent B includes polyols.

[0120] Preferably, the polyols include low-molecular-weight polyols and / or high-molecular-weight polyols.

[0121] Preferably, the low-molecular-weight polyol is a compound containing at least 2 hydroxyl groups and having a number-average molecular weight of 60 - 400 (such as 80, 100, 150, 200, 250, 300, or 350, etc.).

[0122] Exemplarily, the low-molecular-weight polyols include, for example, dihydric alcohols such as ethylene glycol, propylene glycol, 1,3-propanediol, 1,4-butanediol, 1,3-butanediol, 1,2-butanediol, 1,5-pentanediol, 1,6-hexanediol, neopentyl glycol, C7-C22 alkane diols, diethylene glycol, triethylene glycol, dipropylene glycol, 3-methyl-1,5-pentanediol, C17-C20 alkane-1,2-diols, isosorbide, 1,3-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, 1,4-cyclohexanediol, hydrogenated bisphenol A, 1,4-dihydroxy-2-butene, 2,6-dimethyl-1-octene-3,8-diol, bisphenol A; trihydric alcohols such as glycerol, trimethylolpropane; tetrahydric alcohols such as pentaerythritol, diglycerol; pentahydric alcohols such as xylitol; hexahydric alcohols such as sorbitol, mannitol, allitol, iditol, dulcitol, adonitol, inositol, dipentaerythritol; heptahydric alcohols such as perseitol; octahydric alcohols such as sucrose, etc.

[0123] In addition, polyalkylene oxides having a number-average molecular weight of 60 to 400 (random and / or block copolymers containing at least two alkylene oxides), which are obtained by adding alkylene oxides such as ethylene oxide and propylene oxide using the above-mentioned alcohol as an initiator, are also included in the low molecular weight polyols.

[0124] Preferably, the high molecular weight polyol is a compound containing at least two hydroxyl groups and having a number-average molecular weight of 400 to 1000 (such as 500, 800, 1000, 2000, 3000, 4000, 5000, 6000, 7000, 8000, or 9000, etc.); more preferably, the number-average molecular weight of the high molecular weight polyol is 400 to 5000.

[0125] Preferably, the high molecular weight polyol includes any one or a combination of at least two of polyether polyols, polyester polyols, polycarbonate polyols, polyurethane polyols, epoxy polyols, vegetable oil polyols, polyolefin polyols, acrylic polyols, polysiloxane polyols, fluoropolyols, and vinyl monomer-modified polyols.

[0126] Exemplarily, the polyether polyols include: polyoxy(C2-C3)alkylene polyols, polytetramethylene ether glycols, polytrimethylene ether glycols, etc. Among them, as the polyoxy(C2-C3)alkylene polyol, for example, an addition polymer of C2-C3 alkylene oxides such as ethylene oxide and propylene oxide (random and / or block copolymer containing at least two alkylene oxides) using the above-mentioned low molecular weight polyol as an initiator can be cited. In addition, as the polyoxy(C2-C3)alkylene, specifically, polyethylene glycol, polypropylene glycol, polyethylene-propylene copolymer, etc. can also be cited. As the polytetramethylene ether glycol, for example, a ring-opening polymer (polytetramethylene ether glycol) obtained by cationic polymerization of tetrahydrofuran, an amorphous polytetramethylene ether glycol obtained by copolymerizing the polymerization unit of tetrahydrofuran with the above-mentioned diol, etc. can be cited. In addition, a plant-derived polytetramethylene ether glycol starting from tetrahydrofuran produced from plant-derived raw materials such as furfural can also be cited. As the polytrimethylene ether glycol, for example, a polyol produced by polycondensation of plant-derived 1,3-propanediol can be cited.

[0127] Exemplarily, the polyester polyols include: condensates obtained by reacting the above-mentioned low molecular weight polyols (preferably diols) with polyacids (preferably diacids) under known conditions.

[0128] Examples of the polybasic acid include saturated aliphatic dicarboxylic acids (C11-C13) such as oxalic acid, malonic acid, succinic acid, methylsuccinic acid, glutaric acid, adipic acid, 1,1-dimethyl-1,3-dicarboxypropane, 3-methyl-3-ethylglutaric acid, azelaic acid, and sebacic acid; unsaturated aliphatic dicarboxylic acids such as maleic acid, fumaric acid, and itaconic acid; aromatic dicarboxylic acids such as phthalic acid, isophthalic acid, terephthalic acid, toluene dicarboxylic acid, and naphthalene dicarboxylic acid; alicyclic dicarboxylic acids such as hexahydrophthalic acid; other carboxylic acids such as dimer acid, hydrogenated dimer acid, and HET acid; acid anhydrides derived from the aforementioned carboxylic acids such as oxalic anhydride, succinic anhydride, maleic anhydride, phthalic anhydride, 2-alkyl (C12-C18) succinic anhydride, tetrahydrophthalic anhydride, trimellitic anhydride; and acyl halides derived from these carboxylic acids such as oxalyl dichloride, adipoyl dichloride, and sebacoyl dichloride.

[0129] In addition, examples of the polyester polyol include vegetable oil-based polyester polyols obtained by subjecting the aforementioned low-molecular-weight polyols to a condensation reaction with a hydroxyl group-containing vegetable oil fatty acid (e.g., castor oil fatty acid containing ricinoleic acid, hydrogenated castor oil fatty acid containing 12-hydroxystearic acid, etc.) under known conditions.

[0130] In addition, examples of the polyester polyol include polycaprolactone polyols, polyvalerolactone polyols obtained by ring-opening polymerization of lactones such as ε-caprolactone and γ-valerolactone using the aforementioned low-molecular-weight polyols (preferably diols) as initiators, and lactone-based polyester polyols obtained by copolymerizing them with the aforementioned diols.

[0131] Exemplarily, the polycarbonate polyol includes, for example, a ring-opening polymer of ethylene carbonate using the aforementioned low-molecular-weight polyol (preferably a diol) as an initiator, and an amorphous polycarbonate polyol obtained by copolymerizing the aforementioned diol with the ring-opening polymer.

[0132] Exemplarily, the polyurethane polyol includes those obtained by reacting the polyester polyol, polyether polyol, and / or polycarbonate polyol obtained in the above manner with the aforementioned polyisocyanate (including HDI, the same hereinafter) at an equivalent ratio of hydroxyl group to isocyanate group (OH / NCO) greater than 1, such as polyester polyurethane polyol, polyether polyurethane polyol, polycarbonate polyurethane polyol, polyester polyether polyurethane polyol, etc.

[0133] Exemplarily, the epoxy polyol includes, for example, an epoxy polyol obtained by reacting the aforementioned low-molecular-weight polyol with a polyfunctional haloalcohol such as epichlorohydrin and β-methylepichlorohydrin.

[0134] Exemplarily, the vegetable oil polyol may include, for example, vegetable oils containing hydroxyl groups such as castor oil and coconut oil. For example, castor oil polyol, or ester-modified castor oil polyol obtained by the reaction of castor oil polyol and polypropylene polyol, etc. may be cited.

[0135] Exemplarily, the polyolefin polyol may include, for example, polybutadiene polyol, partially saponified ethylene-vinyl acetate copolymer, etc.

[0136] Exemplarily, the acrylic polyol may include, for example, a copolymer obtained by copolymerizing an acrylic ester containing a hydroxyl group and a copolymerizable vinyl monomer copolymerizable with the acrylic ester containing a hydroxyl group.

[0137] Among them, as the acrylic ester containing a hydroxyl group, for example, 2-hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, hydroxybutyl (meth)acrylate, 2,2-dihydroxymethylbutyl (meth)acrylate, polyhydroxyalkyl maleate, polyhydroxyalkyl fumarate, etc. may be cited. Preferably, 2-hydroxyethyl (meth)acrylate, etc. may be cited.

[0138] As the copolymerizable vinyl monomer, for example, (meth)acrylic acid alkyl esters (C1-C12) such as methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, isopropyl (meth)acrylate, butyl (meth)acrylate, isobutyl (meth)acrylate, sec-butyl (meth)acrylate, tert-butyl (meth)acrylate, pentyl (meth)acrylate, isopentyl (meth)acrylate, hexyl (meth)acrylate, isononyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, cyclohexyl acrylate, isobornyl (meth)acrylate, etc., and aromatic vinyl monomers such as styrene, vinyltoluene, α-methylstyrene, etc., vinyl cyanides such as (meth)acrylonitrile, etc., vinyl monomers containing a carboxyl group such as (meth)acrylic acid, fumaric acid, maleic acid, itaconic acid, etc. or their alkyl esters, alkane polyol poly(meth)acrylates such as ethylene glycol di(meth)acrylate, butanediol di(meth)acrylate, hexanediol di(meth)acrylate, oligoethylene glycol di(meth)acrylate, trimethylolpropane di(meth)acrylate, trimethylolpropane tri(meth)acrylate, etc., vinyl monomers containing an isocyanate group such as 3-(2-isocyanato-2-propyl)-α-methylstyrene, etc. may be cited.

[0139] Moreover, the acrylic polyol can be obtained by copolymerizing these acrylic esters containing a hydroxyl group and copolymerizable vinyl monomers in the presence of a suitable solvent and a polymerization initiator.

[0140] In addition, the acrylic polyol may include polysiloxane polyol, fluoropolyol.

[0141] Exemplarily, the polysiloxane polyol may be, for example, an acrylic polyol obtained by copolymerizing the above-mentioned acrylic polyol with a vinyl group-containing polysiloxane compound such as γ-methacryloxypropyltrimethoxysilane as a copolymerizable vinyl monomer.

[0142] Exemplarily, the fluoropolyol may be, for example, an acrylic polyol obtained by copolymerizing the above-mentioned acrylic polyol with a vinyl group-containing fluorine compound such as tetrafluoroethylene or chlorotrifluoroethylene as a copolymerizable vinyl monomer.

[0143] Exemplarily, the vinyl monomer-modified polyol can be obtained by reacting the above-mentioned high-molecular-weight polyol with a vinyl monomer such as the above-mentioned (meth)acrylic acid alkyl ester.

[0144] The above polyol components can be used alone or in combination of two or more.

[0145] In addition, if necessary, a urethanization catalyst, a hydrolysis inhibitor, an antifoaming agent, a surfactant, a lubricity-imparting agent, a surface conditioner, an antioxidant, a weather resistance stabilizer, a pigment, a dye, a filler, a resin powder, etc. can be incorporated into the agent B in an appropriate proportion.

[0146] Preferably, as a method for forming the two-component polyurethane composition into a coating material, for example, the agent A and the agent B are mixed, and the mixture is applied to an object to be coated by a known method and cured. Thereby, a coating material (coating) can be formed. Such a coating material has excellent color fastness.

[0147] As a preferred technical solution of the present invention, as a polyurethane coating, the coating formed by the two-component polyurethane composition has excellent color fastness, good color stability under high temperature and high humidity, and the color difference Δb of the coating after a damp heat durability test (2000 h) is ≤1.2. For example, Δb can be 1.15, 1.1, 1.05, 1.0, 0.9, 0.8, 0.7, 0.6, 0.5, etc., and further preferably <1.2.

[0148] Compared with the prior art, the present invention has the following beneficial effects:

[0149] 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 the polyurethane coating material has excellent color fastness, maintains excellent color stability under high temperature and high humidity environments, and the color difference Δb of the coating after a damp heat durability test of 2000 h is ≤1.2, significantly improving the yellowing resistance and appearance of the coating. Description of the Drawings

[0150] Figure 1 Schematic flow diagram of the preparation method of the isocyanate composition described in a specific embodiment of the present invention;

[0151] Among them, 10 - phosgenation process, 20 - removal process, 30 - separation process, 40 - heavy component recovery process, 50 - refining process. Specific Embodiment

[0152] The technical solution 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.

[0153] The test methods for the components and properties in the present invention are as follows:

[0154] 1. Determination of the mass content (A value) of chlorine in the isocyanate composition: XRF test

[0155] Instrument: Energy dispersive X - ray fluorescence spectrometer (ED - XRF), model: MERAK - LE II;

[0156] Method: Standard addition method

[0157] Principle and operation: 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. 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.

[0158] 2. Determination of the mass content (B value) of chloro - isocyanate in the isocyanate composition: GCMS test

[0159] Analysis is carried out using gas chromatography - mass spectrometry under the following conditions. The content in this article is the normalized content.

[0160] Analysis instrument: Agilent 5977B GCMS

[0161] Chromatographic column: DB - 5 chromatographic column, specifications: 30m × 0.25mm × 0.25μm

[0162] Column oven temperature: Maintain at 50°C for 2 min, then 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

[0163] Split ratio: Splitless

[0164] Injection port temperature: 280°C

[0165] Detection temperature: 300°C

[0166] Carrier gas: helium

[0167] Carrier gas flow rate: 1 mL / min (constant flow rate)

[0168] Sample injection volume: 1 μL

[0169] Detection method: SIM selected ion scanning mode (for HDI, selected ions 160 / 126; for PDI, selected ions 146 / 112; for HMDI, selected ions 254 / 220; for IPDI, selected ions 214 / 180)

[0170] 3. Determination of the mass percentage content of isocyanate in the isocyanate composition: Gas chromatography test

[0171] Analysis is carried out using gas chromatography under the following conditions, and the content in this article is the normalized content.

[0172] Analytical instrument: Agilent 7890B GC

[0173] Chromatographic column: DB-5 chromatographic column, with specifications of 30 m × 0.25 mm × 0.25 μm

[0174] Column oven temperature: Maintain at 50 °C for 1 min, then increase the temperature to 300 °C at a rate of 10 °C / min and maintain for 5 min

[0175] Separation ratio: 30:1

[0176] Injector temperature: 280 °C

[0177] Detection temperature: 320 °C

[0178] Carrier gas: nitrogen

[0179] Carrier gas flow rate: 1 mL / min (constant flow rate)

[0180] Sample injection volume: 1 μL

[0181] Detector: FID

[0182] In the following specific embodiments of the present invention, unless otherwise specified, "parts" and "%" are based on mass.

[0183] Example 1

[0184] An HDI composition and its preparation method, the effective factor E of the HDI composition is 4.70, and the flow schematic diagram of its preparation method is as Figure 1 shown, and specifically includes the following steps:

[0185] Phosgenation process: 1,6 - hexanediamine that has been preheated and vaporized is fed into the phosgenation reactor at a rate of 1000 parts by mass per hour, while phosgene is fed at a rate of 5112 parts by mass per hour. The feed temperatures of the two feed streams are 310 °C. After passing through the reaction zone of the phosgenation reactor, the reaction liquid is obtained by chloro - benzene absorption; among them, the feed pressures of 1,6 - hexanediamine and phosgene are 0.25 MPa, the absolute pressure in the reaction zone is 0.09 MPa, slightly lower than the atmospheric pressure; the molar ratio of phosgene to 1,6 - hexanediamine in the feed is 6:1, the temperature in the reaction zone is 350 °C, the flow rate is 70 m / s, the average contact time is 2 s, and the Reynolds number is 5000. The reactor outlet is absorbed by cold chloro - benzene, and the temperature after absorption is 140 °C to obtain the reaction liquid; thus, 1,6 - hexanediamine reacts with phosgene to generate HDI, and a reaction product containing HDI is obtained.

[0186] Removal process: The reaction product obtained from the phosgenation process is continuously fed into the phosgene - stripping tower and the solvent - stripping tower for phosgene - stripping treatment and solvent - stripping treatment respectively. Thus, 1440 parts by mass of the crude product of HDI are prepared.

[0187] Separation process: The crude product obtained from the removal process is continuously fed into a short - path evaporator to obtain 1418.7 parts by mass of an intermediate product with heavy components removed and 21.3 parts by mass of a primary heavy component.

[0188] Heavy - component recovery process: The primary heavy component is continuously fed into a secondary short - path evaporator to obtain 14.3 parts by mass of a heavy - component recovery material and 7.0 parts by mass of a residual heavy component; the heavy - component recovery material can be obtained through multiple cycles of the short - path evaporator. Next, the intermediate product at a rate of 1418.7 parts by mass per hour is mixed with the heavy - component recovery material at a rate of 14.3 parts by mass per hour to obtain a mixture, that is, the mass percentage content of the heavy - component recovery material in the mixture is 1%.

[0189] Purification process: The aforementioned mixture is continuously fed into a distillation column at a rate of 1433 parts by mass per hour. For the distillation column, it is filled with packing equivalent to 25 theoretical plates. Then, in the distillation column, light components are removed from the top, and an HDI composition is withdrawn from the middle to obtain the target product;

[0190] The distillation conditions in the distillation column are as follows:

[0191] Bottom temperature: 120 - 130 °C

[0192] Top temperature: 80 - 100 °C

[0193] Top pressure: 10 - 50 PaA

[0194] Residence time: 2 - 3 h

[0195] Top reflux ratio: 10

[0196] Output of the rectification process: 1329 mass parts / h.

[0197] Thus, the HDI composition is obtained, wherein the mass content of HDI > 99%, the mass content of chlorine (A value) is 22.2 ppm, the mass content of chloro isocyanate CHI (B value) is 10 ppm, and the effective factor E is 4.70.

[0198] Examples 2 - 5, Comparative Examples 1 - 2

[0199] An HDI composition and its preparation method, the effective factor E of the HDI 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" means the molar amount of phosgene in the phosgenation process based on 1 mol of 1,6 - hexanediamine; "re - component recovery material ratio" means the mass percentage of the re - components (recovery materials) in the mixture in the re - component recovery process.

[0200] Table 1

[0201]

[0202]

[0203] Examples 6 - 10, Comparative Examples 3 - 4

[0204] A PDI composition and its preparation method, the effective factor E of the PDI 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" means the molar amount of phosgene in the phosgenation process based on 1 mol of 1,5 - pentanediamine; "re - component recovery material ratio" means the mass percentage of the re - components (recovery materials) in the mixture in the re - component recovery process.

[0205] Table 2

[0206]

[0207]

[0208] Examples 11 - 15, Comparative Examples 5 - 6

[0209] An HMDI composition and its preparation method. The effective factor E of the HMDI composition is shown in Table 3 respectively. The process flow of its preparation method is the same as that of Example 1, with the difference only in some process parameters, 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, the "phosgene molar ratio" represents the molar amount of phosgene in the phosgenation process based on 1 mol of 4,4'-diaminodicyclohexylmethane; the "recombinant fraction recovery ratio" represents the mass percentage of the recombinant fraction (recovery material) in the mixture in the recombinant fraction recovery process.

[0210] Table 3

[0211]

[0212]

[0213] Examples 16 - 20, Comparative Examples 7 - 8

[0214] An IPDI composition and its preparation method. The effective factor E of the IPDI composition is shown in Table 4 respectively. The process flow of its preparation method is the same as that of Example 1, with the difference only in some process parameters, which are specifically shown in Table 4 (the processes / parameters not shown in Table 4 are exactly the same as those in Example 1). In Table 4, the "phosgene molar ratio" represents the molar amount of phosgene in the phosgenation process based on 1 mol of isophorone diamine; the "recombinant fraction recovery ratio" represents the mass percentage of the recombinant fraction (recovery material) in the mixture in the recombinant fraction recovery process.

[0215] Table 4

[0216]

[0217]

[0218] Examples 21 - 24 and Comparative Examples 9 - 12

[0219] The method in Example 8 of the prior art CN101962348A was used to prepare HDI as Comparative Example 9. This comparative example is the preparation of HDI by the thermal cracking method, and the product does not contain chlorine and thus does not contain the effective factor. The recombinant fraction recovery material in Example 1 was added to this product at a ratio of 4% (i.e., the mass percentage of the recombinant fraction in the resulting mixture was 4%) to obtain Example 21.

[0220] Similarly, the method in Example 1 of the prior art CN114105825A was used to prepare PDI as Comparative Example 10; the recombinant fraction recovery material in Example 6 was added to this product at a ratio of 4% (i.e., the mass percentage of the recombinant fraction in the resulting mixture was 4%) to obtain Example 22.

[0221] The method of Example 4 of the prior art CN101234998A was used to prepare HMDI as Comparative Example 11; the heavy component recycle material in Example 11 was added to this product at a ratio of 4% (i.e., the mass percentage of the heavy component in the resulting mixture was 4%) to obtain Example 23.

[0222] The method of Example 1 of the prior art CN114507161A was used to prepare IPDI as Comparative Example 12; the heavy component recycle material in Example 16 was added to this product at a ratio of 4% (i.e., the mass percentage of the heavy component in the resulting mixture was 4%) to obtain Example 24.

[0223] Application Example

[0224] A two-component polyurethane composition, specifically a two-component polyurethane coating material (paint), comprising Component A and Component B.

[0225] Specifically, this application example provides 2 types of Component A, denoted as Component A-1 and Component A-2, which are respectively paired with Component B as two-component polyurethane coating materials; the formulations are as follows:

[0226] (1) Preparation of Component A-1: By mass, 413.7 parts of an HDI composition (37.7 parts by mass for the PDI composition, 39.9 parts by mass for the HMDI composition, 39.9 parts by mass for the IPDI composition) were mixed with 36.7 parts of trimethylolpropane, and the reaction was carried out at 70 °C for 6 h under a nitrogen atmosphere; the reaction solution obtained was distilled using a thin-film distillation device to distill off the unreacted isocyanate, thereby obtaining a modified isocyanate composition, and the modified isocyanate composition contains urethane groups obtained by the reaction of isocyanate with trimethylolpropane; the aforementioned isocyanate compositions were the isocyanate compositions provided in Examples 1-24 and Comparative Examples 1-12 respectively;

[0227] Ethyl acetate was added to the modified isocyanate composition in such a way that the solid content became 75 wt.%, and a polyisocyanate component (Component A-1) was produced. The content of the NCO group in the polyisocyanate component was 11.6 wt.%.

[0228] (2) Preparation of Agent A-2: By mass, 2 parts of 1,3-butanediol were added to 100 parts of an HDI composition (37.7 parts by mass for the PDI composition, 39.9 parts by mass for the HMDI composition, and 39.9 parts by mass for the IPDI). The temperature was raised to 75 °C under a nitrogen atmosphere, and a urethanization reaction was carried out for 2 h. The equivalent ratio of the isocyanate group to the hydroxyl group of 1,3-butanediol in the isocyanate composition (NCO / OH) was 24; then, at the same temperature, as an isocyanurate esterification catalyst, a solution of tetrabutylammonium hydroxide (37% methanol solution) 0.1 phr (converted to a solid component of 0.037 phr) was added, and the isocyanurate esterification reaction was terminated after 4 h; the resulting reaction solution was passed through a thin-film distillation apparatus (temperature 150 °C, vacuum 50 Pa) to remove the unreacted isocyanate (distillation yield 60 wt.%), thereby obtaining a modified isocyanate composition; the modified isocyanate composition contains the isocyanurate group of the isocyanate trimer; the aforementioned isocyanate compositions are the isocyanate compositions provided in Examples 1-24 and Comparative Examples 1-12 respectively;

[0229] Ethyl acetate was added to the modified isocyanate composition in such a way that the solid component became 75 wt.%, to produce a polyisocyanate component (Agent A-2).

[0230] (3) Preparation of Agent B: By mass, 40 parts of a fluoropolyol (ZEFFLE GK-570, manufactured by DAIKIN INDUSTRIES LTD., solid component hydroxyl value: 64 mg KOH / g, solvent is butyl acetate), 52.5 parts of titanium oxide (CR93, manufactured by Ishihara Sangyo Kaisha), 33.8 parts of butyl acetate, and 110 parts of glass beads with a diameter of 2 mm were stirred for 2 h using a paint stirrer, then the glass beads were filtered out, and then butyl acetate was added in such a way that the solid component concentration became 58 wt.%, to obtain Agent B, where the proportion of titanium oxide was 45 wt.%.

[0231] (4) Preparation of a two-component polyurethane coating material: The obtained Agent A (Agent A-1 or Agent A-2) and Agent B were mixed in such a way that the equivalent ratio of the isocyanate group to the hydroxyl group (NCO / OH) became 1.0 to prepare a mixed solution, and then butyl acetate was added to the mixed solution in such a way that the NV value (coating film component mass, solid content) became 60 wt.%, to obtain the two-component polyurethane coating material.

[0232] Performance evaluation:

[0233] The two-component polyurethane coating material to be tested was coated on the surface of a polyethylene terephthalate (PET) substrate and cured by heating at 120 °C for 2 min; then the PET substrate coated with the mixture was cured at 60 °C for 2 days. Thus, a coating with a thickness of about 15 μm was formed on the PET substrate.

[0234] The weather resistance of the coating (color difference of the coating in the damp heat test) was measured as follows: The initial b value (b1, initial value) of the coating was measured using a color difference meter (3nh NR10QC); then the sample coated with the coating was placed in a thermo-hygrostat (Gaotie Instruments) and maintained at 85 °C and a relative humidity of 85% for 2000 h; the b value (b2) of the sample after 2000 h of damp heat durability test was measured in the same manner as above, and the color difference Δb of the coating before and after the damp heat test was calculated, Δb = ∣b2 - b1∣; the results are shown in Tables 5 - 8.

[0235] Table 5

[0236]

[0237]

[0238] Table 6

[0239]

[0240] Table 7

[0241]

[0242]

[0243] Table 8

[0244]

[0245]

[0246] Combined with the above performance test data, it can be seen that in the present invention, by controlling the effective factor of the isocyanate composition within the range of 3.70 - 4.70, the prepared two-component polyurethane coating material has excellent color fastness, good color stability under high temperature and high humidity, and the color difference Δb of the coating after the damp heat durability test (2000 h) is < 1.2, as low as 0.98 - 1.19.

[0247] The applicant declares that the present invention illustrates the isocyanate composition, its preparation method and application through the above-mentioned embodiments. However, 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, the equivalent substitution of the raw materials selected for the present invention, the addition of auxiliary components, the selection of specific methods, etc. all fall within the protection scope and the disclosure scope of the present invention.

Claims

1. An isocyanate composition, characterized in that, The effective factor of the isocyanate composition is 3.70 - 4.70; 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; A is 2 - 1000 ppm; B is the mass content of chloro - isocyanate in the isocyanate composition; B is 5 - 3000 ppm; M Cl is the relative atomic mass of chlorine; M B is the relative molecular mass of the chloro isocyanate; A is obtained by X - ray fluorescence spectrometry; B is obtained by gas chromatography - mass spectrometry; The isocyanate composition includes a combination of isocyanate and chlorine - containing substances; The chlorine - containing substances include a combination of chloro - isocyanate and substances corresponding to the effective factor; The substances corresponding to the effective factor include any one or at least two combinations of the following compounds: wherein R is a divalent group obtained by removing the NCO group in the isocyanate; The chloro - isocyanate is a compound in which one NCO group in the isocyanate is replaced by chlorine; The isocyanate is selected from any one of pentamethylene diisocyanate, hexamethylene diisocyanate, dicyclohexylmethane diisocyanate, and isophorone diisocyanate.

2. The isocyanate composition according to claim 1, characterized in that, The mass percentage content of isocyanate in the isocyanate composition is ≥97%; 3. The isocyanate composition according to claim 1, characterized in that, R is selected from any one of ; wherein, the wavy line represents the connection site of the group.

4. The isocyanate composition according to claim 1, characterized in that, The chloro isocyanate is selected from any one of them.

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, characterized in that, 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 is refined to obtain the isocyanate composition.

9. The preparation method according to claim 7, characterized in that, The refining method is distillation.

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

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

12. A two-component polyurethane composition, characterized in that, The two - component polyurethane composition includes Agent A and Agent B; The Agent A includes the isocyanate composition as described in any one of Claims 1-5 and / or the modified isocyanate composition as described in Claim 10; The Agent B includes a substance containing an active hydrogen group.

13. The two-component polyurethane composition according to claim 12, characterized in that, The modified isocyanate composition contains group (a) isocyanurate group and / or group (d) carbamate group.

14. The two-component polyurethane composition according to claim 12, characterized in that, The Agent B includes a polyol.

Images