CN115850650A - Isocyanate composition and preparation method and application thereof - Google Patents

Abstract

The invention provides an isocyanate composition, a preparation method and an application thereof, wherein the effective factor of the isocyanate composition is 3.70-4.70, and the isocyanate composition has excellent reaction activity through the design and control of the effective factor and can be used for preparing high-performance polyurethane products. The isocyanate composition can effectively improve the stability of polyurethane products, particularly enables the polyurethane coating material to have excellent discoloration resistance, keeps excellent color stability in high-temperature and high-humidity environments, has the color difference delta b of the coating after a damp-heat durability test of 2000h less than or equal to 1.2, and obviously improves the yellowing resistance and appearance of the coating.

Description

Isocyanate composition and preparation method and application thereof

Technical Field

The invention belongs to the technical field of isocyanate, and particularly relates to an isocyanate composition, and a preparation method and application thereof.

Background

The polyurethane coating has the advantages of low film forming temperature, strong adhesive force, good wear resistance, large hardness, good chemical resistance, good weather resistance and the like, and is widely used in industrial protective paint, wood furniture paint, automobile original factory paint and automobile refinishing paint. Polyurethane coatings are generally composed of isocyanates and polyols, and aliphatic isocyanates have relatively superior stability compared to aromatic isocyanates and are more commonly used raw materials in polyurethane coatings. The aliphatic isocyanate may be classified into a linear aliphatic isocyanate and a cyclic aliphatic isocyanate according to a molecular structure, typical examples of the former include Hexamethylene Diisocyanate (HDI) and the like, and the latter is also referred to as an alicyclic isocyanate, and typical examples include dicyclohexylmethane diisocyanate (HMDI), isophorone diisocyanate (IPDI), and the like.

Although aliphatic isocyanates such as HDI, HMDI, IPDI have various advantages, they also have the following disadvantages: due to the existence of trace impurities in the synthesis process, the isocyanate has dark color and can generate side reaction in the subsequent modification process, so that the prepared products such as polyurethane paint and the like have insufficient discoloration resistance.

Isocyanates can be prepared by reacting the corresponding amines with phosgene (phosgene), and in order to compensate for the disadvantages of isocyanates, researchers have started with the preparation of isocyanates and achieved the improvement of the product properties by controlling the raw materials. For example, CN101440046A discloses the preparation of light-colored isocyanates by reacting the corresponding amines with phosgene in the presence or absence of an inert medium, the amine streams fed to the phosgenation reaction having average a PRI value below 60 moles per million moles (mpm), PRI representing polarographically reducible impurities; in the preparation method, HDI is prepared by controlling the polarographic value PRI of the hexanediamine, and then polymerization reaction is carried out, so that HDI tripolymer with low color number can be obtained. CN103319372A discloses a method for preparing light-colored or colorless dicyclohexylmethane diisocyanate, which comprises: a) Purifying a raw material dicyclohexyl methane diamine to obtain dicyclohexyl methane diamine containing alcohol compounds with the weight percent of less than 0.2%; b) The dicyclohexylmethane diisocyanate obtained by the method has the characteristics of light color or colorless. CN1356980A discloses light-colored isocyanate, a preparation method and application thereof, wherein phosgene containing less than 50ppm of molecules or combined bromine or iodine or a mixture thereof is used as a raw material and is reacted with amine to prepare the isocyanate; the method realizes the preparation of light-colored isocyanate by controlling the content of bromide and iodide in phosgene, so that the isocyanate has lower iodine color value IFZ. CN109761855A discloses a method for preparing isophorone diisocyanate, which comprises the following steps: reacting isophorone with hydrogen cyanide to obtain isophorone nitrile; reacting isophorone nitrile, ammonia gas and hydrogen in the presence of a catalyst to obtain isophorone diamine; carrying out phosgenation on isophorone diamine to obtain isophorone diisocyanate; wherein, the content of impurities containing secondary amino in the isophorone diamine subjected to the phosgenation reaction is less than or equal to 0.5wt%; the method effectively reduces the content of the hydrolysis chlorine in the isophorone diisocyanate product and the chroma of the product.

In the preparation method of isocyanate disclosed in the prior art, the improvement of the color of the isocyanate is realized to a certain extent by controlling the polarographic value of amine, the content of alcohol impurities in the amine, the content of secondary amine group impurities in the amine, the content of impurities in phosgene and the like, but the color of light-colored isocyanate is deepened in the subsequent modification and production of polyurethane products, so that the obtained polyurethane products have serious weather resistance problems and are obviously yellowed after long-term use, thereby influencing the appearance and the service performance of the polyurethane products, particularly polyurethane paint and coatings.

Therefore, the development of isocyanates with excellent properties to improve the discoloration resistance of polyurethane articles, especially polyurethane coatings and coatings, is a research focus in this field.

Disclosure of Invention

In view of the defects of the prior art, the invention aims to provide an isocyanate composition, a preparation method and application thereof, wherein the isocyanate composition can be used for preparing a high-performance polyurethane product through the design and control of an effective factor, and the discoloration resistance of the polyurethane product, especially a polyurethane coating material and a polyurethane coating is obviously improved.

In order to achieve the purpose, the invention adopts the following technical scheme:

in a first aspect, the present invention provides an isocyanate composition having an effective factor of from 3.70 to 4.70.

The calculation formula of the effective factor is shown as formula I:

in the formula I, E is an effective factor;

in the formula I, A is the mass content of chlorine in the isocyanate composition.

In the formula I, B is the mass content of the chlorinated isocyanate in the isocyanate composition.

In the formula I, M _Cl Is the relative atomic mass of chlorine.

In the formula I, M _B Is the relative molecular mass of the chlorinated isocyanate.

The isocyanate composition provided by the present invention has an effective factor E of 3.70 to 4.70, which may 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, and the specific values therebetween, are not intended to be limiting to the space and for the sake of brevity, and the present invention is not exhaustive of the specific values included in the ranges.

In the present invention, the isocyanate composition comprises a combination of isocyanate and chlorine-containing material, and is therefore defined as "composition"; the chlorine-containing substance comprises a combination of chlorinated isocyanate and a substance corresponding to an effective factor. The isocyanate composition comprises specific contents of specific types of chlorine-containing substances through the design and control of effective factors, so that the isocyanate composition has excellent reactivity and can be used for preparing high-performance polyurethane products. The isocyanate composition can effectively improve the discoloration resistance and stability of a polyurethane product, particularly enables a polyurethane coating material to have excellent discoloration resistance, keeps excellent color stability in high-temperature and high-humidity environments, and obviously improves the yellowing resistance and appearance of a coating. If the effective factor of the isocyanate composition is too high or too low, the discoloration resistance of the polyurethane coating material is reduced, and the coating layer is significantly yellowed under the conditions of high temperature and high humidity.

In the formula I for calculating the effective factor, A is the mass content of chlorine in the isocyanate composition and is obtained by X-ray fluorescence spectrum analysis (XRF) test.

In the invention, in formula I for calculating the effective factor, B is the mass content of the chlorinated isocyanate in the isocyanate composition, and is preferably obtained by a chromatography-mass spectrometry test, and is further preferably obtained by a gas chromatography-mass spectrometry (GCMS) test.

In the research of the invention, the characterization method of the chlorine content in the isocyanate disclosed by the prior art can not accurately control the performance of the isocyanate, so that the quality of a polyurethane product, particularly the discoloration resistance of a polyurethane coating material, can not be effectively controlled. Specifically, the test method for the total chlorine content in the standard GB/T12009.1-1989 is an oxygen bottle combustion method, all chlorine (including bromine) in isocyanate is converted into inorganic chlorine (including bromine), and then titration is carried out by using silver nitrate, and all the chlorine content in the isocyanate is characterized, and the bromine content in the isocyanate is included. The determination of hydrolytic chlorine by the standard GB/T12009.2-2016, specifically the chlorine released after the reaction of isocyanate with alcohol and water, is the chlorine with higher activity in isocyanate, also includes bromine with higher activity, and part of monochloro isocyanate can also be hydrolyzed. The chlorine (including a part of bromine) content measured in GB/T12009.1-1989 or GB/T12009.2-2016 does not accurately indicate the composition information of the isocyanate, and thus the properties of the isocyanate and polyurethane article cannot be effectively controlled.

According to the preferable technical scheme, in the calculation of the effective factor E, A is XRF (bromine-free) content, B is chloro-isocyanate content obtained by adopting a chromatography-mass spectrometry test, and A value and B value are obtained by adopting an accurate qualitative and quantitative analysis method, so that the effective factor E accurately represents polychlorinated substances and partial hydrolytic chlorine (not containing hydrolytic chlorine of monochloro-isocyanate) in the isocyanate composition, and correspondingly has a finer and more definite chlorine content, and the partial chlorine content plays a key role in the activity of isocyanate and the performance of a polyurethane product (polyurethane coating material), thereby realizing the performance regulation and control of the isocyanate composition, further effectively improving the performance of the polyurethane product prepared by the effective factor E, and particularly having a remarkable improvement effect on the discoloration resistance of the polyurethane coating material.

Preferably, the isocyanate is a diisocyanate, more preferably an aliphatic diisocyanate, including a chain aliphatic diisocyanate and/or a cyclic aliphatic diisocyanate (alicyclic diisocyanate).

Preferably, the isocyanate includes any one of Pentamethylene Diisocyanate (PDI), hexamethylene Diisocyanate (HDI), dicyclohexylmethane diisocyanate (HMDI), isophorone diisocyanate (IPDI) or a combination of at least two thereof.

In the present invention, unless otherwise specified, the isocyanate includes all isomers thereof, for example, dicyclohexylmethane diisocyanate (HMDI) is

Preferably, the isocyanate content in the isocyanate composition is 97% by mass or more, for example, 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 more preferably 99% by mass or more.

Preferably, the substance corresponding to the effective factor comprises any one or a combination of at least two of the following compounds:

wherein R is a divalent group obtained by removing NCO groups in isocyanate.

Preferably, R is selected from C6 linear or branched alkylene (e.g.

Isocyanate is HDI), C5 straight-chain or branched alkylene (e.g.. ANG.))>

Isocyanate is PDI), or is/are>

(isocyanate is HMDI),. Or->

(isocyanate is IPDI) and any one or a combination of at least two of the above; wherein the wavy line represents the attachment site of the group.

Preferably, the chlorinated isocyanate is a compound obtained by replacing one NCO group in isocyanate with chlorine.

Preferably, the chlorinated isocyanate comprises OCN-R ¹ -CI (chlorohexyl isocyanate CHI, isocyanate HDI), OCN-R ² -CI (chloropentyl isocyanate CPI, isocyanate PDI),

(chlorodicyclohexylmethane isocyanate CHMI, isocyanate HMDI),. Or>

(chloro isophorone diisocyanate CIPI, isocyanate is IPDI) or any one or combination of at least two of the above; wherein R is ¹ Is C6 straight-chain or branched alkylene (e.g.. Based on;)>

)，R ² Is C5 straight-chain or branched alkylene (e.g.

)。

Preferably, the chlorinated isocyanate comprises

Any one or a combination of at least two of them.

As used herein, the expression "-" underlined loop structure means that the attachment site is located at any position on the loop structure where it can be bonded.

Preferably, the isocyanate composition has a chlorine content (value a) of 2 to 1000ppm, for example 5ppm, 10ppm, 50ppm, 100ppm, 150ppm, 200ppm, 250ppm, 300ppm, 350ppm, 400ppm, 450ppm, 500ppm, 550ppm, 600ppm, 650ppm, 700ppm, 750ppm, 800ppm, 850ppm, 900ppm or 950ppm, and the specific values therebetween are not exhaustive and for the sake of brevity, the invention does not exclude the specific values included in the range, and more preferably 20 to 900ppm.

Preferably, the isocyanate composition has a mass content of chlorinated isocyanate (B value) of 5 to 3000ppm, for example 20ppm, 50ppm, 100ppm, 300ppm, 500ppm, 700ppm, 900ppm, 1000ppm, 1100ppm, 1300ppm, 1500ppm, 1700ppm, 1900ppm, 2000ppm, 2100ppm, 2300ppm, 2500ppm, 2700ppm or 2900ppm, and the specific values therebetween are not exhaustive for reasons of space and simplicity, and the invention is not exhaustive of the specific values included in the ranges.

In the present invention, "ppm" is a parts per million ratio, 1ppm represents one part per million; the same expressions are used hereinafter to have the same meanings.

In the present invention, the substance corresponding to the above-mentioned effective factor, i.e., the chlorinated isocyanate, may be produced as a by-product in the production process of the isocyanate, or may be artificially added to obtain a desired content.

In a second aspect, the present invention provides a process for the preparation of an isocyanate composition as described in the first aspect, said process comprising: and (3) reacting an amine compound with phosgene to obtain the isocyanate composition.

Preferably, the preparation method comprises the following steps:

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

(2) Removing the reaction product obtained in the step (1) to obtain a crude product; the removal treatment comprises a phosgene removal treatment and/or a solvent removal treatment;

(3) And (3) sequentially separating and refining the crude product obtained in the step (2) to obtain the isocyanate composition.

Preferably, the separation in the step (3) obtains heavy components and intermediate products; refining the mixture of the intermediate product and the heavy component to obtain the isocyanate composition; the mass percentage of the heavy components in the mixture is 1-10%.

As a preferred technical scheme of the invention, the component for refining is a mixture of the intermediate product and the heavy component, the mass percentage of the heavy component in the mixture is 1-10%, for example, 2%, 3%, 4%, 5%, 6%, 7%, 8% or 9%, and specific values between the above values are limited by space and simplicity, and the invention does not exhaustively enumerate the specific values included in the range, and further preferably 2-10%.

Preferably, the heavy component obtained by separation can be directly mixed with an intermediate product to obtain a mixture; or the separated heavy component is a first-stage heavy component, and the first-stage heavy component is separated again to obtain a heavy component recycled material and a residual heavy component; mixing the heavy component reclaimed materials with an intermediate product to obtain a mixture; the mass percentage of the heavy component recovery material in the mixture is 1-10%.

In another preferred embodiment, the isocyanate composition is prepared by a method comprising: and mixing the isocyanate obtained by a carbamate cracking method with the heavy component reclaimed material to obtain the isocyanate composition. Preferably, the mass percentage of the heavy component recyclates in the isocyanate composition is from 1 to 10% (e.g. 2%, 3%, 4%, 5%, 6%, 7%, 8% or 9%, etc.), more preferably from 1 to 5%.

As a preferred technical scheme of the invention, the preparation method of the isocyanate composition is a phosgenation method, namely, an amine compound and phosgene are reacted to generate isocyanate; the amine compound includes a diamine and/or a diamine salt (e.g., a diamine hydrochloride salt obtained by reacting a diamine with HCl).

Preferably, the method of reacting the amine compound with phosgene illustratively includes the following three types: the method of reacting diamines with phosgene in the gas phase, also known as the gas phase phosgenation method; a method of reacting diamine with phosgene in a liquid phase, also called a liquid phase phosgenation method; a method of reacting a diamine salt (e.g., diamine hydrochloride) with phosgene in a solvent is also called phosgenation of diamine hydrochloride, and further preferably a gas phase phosgenation.

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

Preferably, the reaction in step (1) is carried out in a gas phase, i.e., a gas phase phosgenation method, the vaporization of the amine compound (diamine) is carried out beforehand, and the resulting diamine in a gas phase does not exist as droplets before entering the reaction zone.

Preferably, the reaction in step (1) can be carried out in a batch operation mode, a semi-continuous operation mode or a continuous operation mode, and a continuous operation mode is further preferred.

Preferably, the inert medium is selected from any one or a combination of at least two of nitrogen, a rare gas (e.g., argon and/or helium), an aromatic compound (e.g., chlorobenzene, dichlorobenzene, toluene, xylene), carbon monoxide, carbon dioxide, and the like, and more preferably from any one or a combination of at least two of nitrogen, chlorobenzene, or dichlorobenzene.

Preferably, the inert medium is used in a volume ratio of (0.01-5): 1, such as 0.02.

Preferably, the specific method of the reaction of step (1) comprises: and (3) reacting the vaporized diamine with phosgene through a reaction zone to obtain a reaction product.

Preferably, the molar ratio of phosgene to amine compound (diamine) is (2.5-20): 1, and for example, can be 3.

Preferably, the reaction temperature in step (1) is 300-500 ℃, for example, 310 ℃, 330 ℃, 350 ℃, 370 ℃, 390 ℃, 400 ℃, 410 ℃, 430 ℃, 450 ℃, 470 ℃ or 490 ℃, and the specific values therebetween are limited by the space and the conciseness, and the invention is not exhaustive list of the specific values included in the range, and more preferably 350-450 ℃.

Preferably, the absolute pressure of the reaction in step (1) is 0.05 to 0.3MPa, such as 0.06MPa, 0.08MPa, 0.1MPa, 0.12MPa, 0.15MPa, 0.18MPa, 0.2MPa, 0.22MPa, 0.25MPa or 0.28MPa, and the specific values therebetween, limited to the space and for the sake of brevity, are not exhaustive and the invention does not include the specific values included in the range, further preferably 0.07 to 0.2MPa, further preferably 0.09 to 0.18MPa.

Preferably, the flow rates of the vaporized diamine and the phosgene feed stream into the reaction zone are each independently in the range of 5-100m/s, and may be, for example, 10m/s, 15m/s, 20m/s, 25m/s, 30m/s, 35m/s, 40m/s, 45m/s, 50m/s, 55m/s, 60m/s, 65m/s, 70m/s, 75m/s, 80m/s, 85m/s, 90m/s or 95m/s, and the specific points therebetween are limited in space and for the sake of brevity, and the invention is not exhaustive of the specific points included in the ranges, and further preferably 10-80m/s.

Preferably, the average contact time of the amine compound (diamine) and phosgene in the reaction zone is 0.01-15s, for example, 0.02s, 0.05s, 0.08s, 0.1s, 0.3s, 0.5s, 0.8s, 1s, 2s, 3s, 4s, 5s, 6s, 7s, 8s, 9s, 10s, 11s, 12s, 13s or 14s, and the specific values therebetween are limited by space and for the sake of brevity, and the invention is not exhaustive, and the specific values included in the range are further preferably 0.04-10s, and more preferably 0.08-5s.

Preferably, the product of the reaction of the amine compound (diamine) and phosgene in step (1) is spray-washed (swabbed) with an inert solvent in a single stage or multiple stages, so that the temperature of the product is reduced to 150 ℃ or less, and the reaction product (isocyanate-containing reaction liquid) is obtained.

Preferably, the inert solvent is an organic solvent, exemplary including but not limited to: aromatic hydrocarbons such as benzene, toluene and xylene, aliphatic hydrocarbons such as octane and decane, alicyclic hydrocarbons such as cyclohexane, methylcyclohexane and ethylcyclohexane, halogenated aromatic hydrocarbons such as chlorotoluene, chlorobenzene, dichlorobenzene, dibromobenzene and trichlorobenzene, nitrogen-containing compounds such as nitrobenzene, N-dimethylformamide, N-dimethylacetamide and N, N' -dimethylimidazolidinone, 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, and the like; the inert solvent may be used alone or in combination of at least two.

Preferably, the inert solvent comprises a halogenated aromatic hydrocarbon, further preferably chlorobenzene and/or dichlorobenzene.

If necessary, the reaction product obtained in step (1) may be subjected to a removal step (desolvation step and/or phosgene removal step) and a separation and purification step.

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

Preferably, the desolvation treatment in the step (2) is carried out in a desolvation tower.

Preferably, the separation in the step (3) separates the intermediate product (light component) and the heavy component, so as to remove the heavy component; the separate devices illustratively include, but are not limited to: short-path evaporator, distillation tower.

Preferably, the operating pressure of the short-path evaporator is 0.05 to 4kPa, and may be, for example, 0.08kPa, 0.1kPa, 0.3kPa, 0.5kPa, 0.8kPa, 1kPa, 1.2kPa, 1.5kPa, 1.8kPa, 2kPa, 2.2kPa, 2.5kPa, 2.8kPa, 3kPa, 3.2kPa, 3.5kPa, or 3.8kPa, and specific points therebetween, limited to space and for the sake of brevity, the invention is not exhaustive and specific points included in the range are not intended, and further preferably 0.1 to 2.5kPa.

As a preferred technical scheme of the invention, the heavy component obtained by separation contains chlorine-containing substances with rich types and high content, and the heavy component or a heavy component reclaimed material obtained by re-separating the heavy component is mixed into an intermediate product (light component) obtained by separation according to a certain proportion and then refined, so that the types and the content of the chlorine-containing substances in the product can be effectively regulated and controlled, and the effective factor of the isocyanate composition is 3.90-5.70.

Preferably, the weight percentage of the heavy components (heavy component-recovered materials) in the mixture (materials participating in the refining) is 1 to 10%, more preferably 2 to 10%, so that the effective factor of the isocyanate composition is 3.70 to 4.70. If the incorporation amount of heavy components (heavy component recovery materials) is too small, the effective factor is higher, and the isocyanate composition used for preparing polyurethane products can cause the reaction rate to be too fast and the discoloration resistance of the isocyanate composition is poor; if the incorporation amount of the heavy component (heavy component reclaimed material) is too high, the effective factor is low, and the isocyanate composition contains more impurities, the discoloration resistance and the stability of a polyurethane product can be influenced, so that the polyurethane coating material can generate obvious yellowing phenomenon in a wet and hot environment.

Preferably, the heavy component mixed with the intermediate product can be directly mixed back into the intermediate product, or can be recycled and separated by a heavy component removing device to obtain a heavy component reclaimed material, and then the heavy component reclaimed material is mixed into the intermediate product.

Preferably, the refining method is an industrial separation technique known in the art, exemplary including but not limited to: distillation, rectification, crystallization and the like.

Preferably, the refining method in the step (3) is rectification.

Preferably, the rectification is carried out in a rectification column, which preferably comprises a plate rectification column or a packed rectification column.

Preferably, the number of theoretical plates of the rectifying column is 2 to 60, and for example, may be 3, 5, 8, 10, 12, 15, 18, 20, 22, 25, 28, 30, 32, 35, 38, 40, 42, 45, 48, 52, 55 or 58, and specific values therebetween, and the invention is not exhaustive and for simplicity, and the specific values included in the range are more preferably 5 to 40.

Preferably, the pressure at the top of the rectification column is 0.1 to 4kPa, and may be, for example, 0.2kPa, 0.5kPa, 0.8kPa, 1kPa, 1.2kPa, 1.5kPa, 1.8kPa, 2kPa, 2.2kPa, 2.5kPa, 2.8kPa, 3kPa, 3.2kPa, 3.5kPa or 3.8kPa, and the specific values therebetween are limited by the space and for the sake of brevity, and the invention is not exhaustive list of the specific values included in the range, and further preferably 0.15 to 2.5kPa.

Preferably, the overhead reflux ratio of the rectification column is 0.01 to 60, and for example, may 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, and specific values therebetween are limited for space and simplicity, and the present invention is not exhaustive and more preferably 0.1 to 40.

In a preferred embodiment of the present invention, the preparation method of the isocyanate composition comprises the following steps:

(1) A phosgenation step: reacting the vaporized diamine with phosgene, and spraying and washing (catching) the generated product by using an inert solvent to obtain a reaction product;

(2) A removing procedure: removing the reaction product obtained in the step (1) to obtain a crude product; the removal treatment comprises a phosgene removal treatment and/or a solvent removal treatment;

(3a) A separation process: separating the crude product obtained in the step (2) to obtain a heavy component and an intermediate product (light component);

(3b) A heavy component recovery process: mixing the intermediate product obtained in the step (3 a) with the heavy component to obtain a mixture; the mass percentage of the heavy components in the mixture is 1-10%; or, carrying out secondary separation on the heavy component obtained in the step (3 a) to obtain a heavy component reclaimed material and a residual heavy component; mixing the heavy component reclaimed materials with an intermediate product to obtain a mixture; the mass percentage of the heavy component recovery material in the mixture is 1-10%;

(3c) A refining step: and (4) refining the mixture obtained in the step (3 b) to obtain the isocyanate composition.

Illustratively, the flow diagram of the preparation method is shown in fig. 1, and includes a phosgenation process 10, a removal process 20, a separation process 30, a heavy component recovery process 40, and a purification process 50. The phosgenation step may be carried out in a batch or continuous manner. The effective factor of the isocyanate composition is adjusted by appropriately adjusting the mixing ratio of the heavy components and the intermediate product, the supply ratio of phosgene, the reaction temperature, the reflux ratio of the rectifying tower, and the like, and the control of the effective factor is mainly realized by the mixing ratio of the heavy components and the intermediate product.

Specifically, taking the HDI composition as an example, the preparation method is as follows:

(1) A phosgenation step: mixing the vaporized 1, 6-hexamethylene diamine with optional nitrogen and then continuously reacting the mixture with phosgene in a tubular reactor by adopting the tubular reactor, and continuously spraying and washing (catching) chlorobenzene after a generated product leaves a reaction area to obtain a reaction product, namely a reaction liquid containing isocyanate.

Thereby, the phosgenation process is continuously performed.

Thus, the salt formation step and the phosgenation step are continuously performed.

(2) A removing procedure: the reaction solution is continuously conveyed to the middle part of the phosgene removing tower by adopting a phosgene removing tower and a desolventizing tower. Removing phosgene, hydrogen chloride and the like from the reaction solution through a phosgene removing tower; and then removing the solvent in the reaction liquid through a solvent removal tower to obtain a HDI crude product.

(3a) A separation process: and (3) separating the HDI crude product by using a short-path evaporator, and removing heavy components to obtain an intermediate product and a first-level heavy component.

(3b) Heavy component recovery process: the primary heavy component is recycled through a short-range evaporator to obtain a heavy component recycled material and a secondary heavy component, and the heavy component recycled material and the secondary heavy component can be recycled once or circularly; the mixture obtained by mixing the heavy component reclaimed material and the intermediate product enters a refining process; the mass percentage of the heavy component recovery material in the mixture is 1-10%.

(3c) A refining step: continuously feeding the mixture into a column of a rectification column; then, the low boiling substance is distilled off from the intermediate product under the aforementioned rectification conditions (bottom temperature, top pressure, bottom reflux ratio, top reflux ratio, residence time), and the HDI composition is withdrawn from the middle part of the column.

Thus, an HDI composition including HDI, CHI, and the substance corresponding to the significant factor can be continuously manufactured.

In a third aspect, the present invention provides a modified isocyanate composition obtained by modifying the isocyanate composition according to the first aspect.

The modified isocyanate composition comprises any one or a combination of at least two of the groups (a) - (i): (a) isocyanurate groups, (b) uretdione groups, (c) biuret groups, (d) urethane groups, (e) urea groups, (f) iminooxadiazinedione groups, (g) allophanate groups, (h) uretonimine groups, (i) carbodiimide groups.

The aforementioned isocyanate composition may be modified as necessary by a person skilled in the art using known methods to obtain the modified isocyanate composition; the modified isocyanate composition is suitably used as a material for a polymer such as polyurethane, as an isocyanate-based material (polyisocyanate component) and an active hydrogen group-containing material.

Specifically, the modified isocyanate composition containing the group (a) isocyanurate group is a trimer of isocyanate, and exemplarily, it can be obtained by reacting an isocyanate composition in the presence of a known isocyanurating catalyst, and isocyanurating the isocyanate therein.

The modified isocyanate composition containing the uretdion group (b) can be obtained by heating the isocyanate composition at 90 to 200 ℃ or reacting the isocyanate composition in the presence of a known uretdionization catalyst to uretdionize (for example, dimerize) the isocyanate.

The modified isocyanate composition containing the biuret group as the group (c) can be obtained by reacting the isocyanate composition with, for example, water, tertiary alcohols (e.g., t-butanol, etc.), secondary amines (e.g., dimethylamine, diethylamine, etc.), etc., and then further reacting them in the presence of a known biuretizing catalyst.

The modified isocyanate composition containing the group (d) urethane group can be obtained by reacting an isocyanate composition with a polyol component (e.g., trimethylolpropane, etc.).

The modified isocyanate composition containing the urea group of the group (e) can be obtained by reacting an isocyanate composition with water, a polyamine component, and the like.

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 iminooxadiazinedionate (e.g., trimerize) the isocyanate.

The modified isocyanate composition containing the group (g) allophanate group can be obtained by further reacting the isocyanate composition after reacting it with an alcohol in the presence of a known allophanatization catalyst.

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.

The modified isocyanate composition comprising the carbodiimide group (i) can be obtained by reacting an isocyanate composition in the presence of a known carbodiimidization catalyst.

The modified isocyanate composition may contain at least 1 of the above-mentioned groups (a) to (i), and may contain at least 2. Such a modified isocyanate composition can be produced by appropriately combining the above-mentioned reactions. The modified isocyanate composition may be used alone or in combination of 2 or more.

Taking the HDI composition as an example, the HDI composition can be modified by a known method as needed by those skilled in the art to obtain a modified HDI composition, which is suitably used as the isocyanate-based substance (polyisocyanate component) and the active hydrogen group-containing substance as the raw material of the polyurethane.

In a fourth aspect, the present invention provides an isocyanate-based polymer formed by reacting an isocyanate-based material with an active hydrogen group-containing material; the isocyanate-based material includes at least one of the isocyanate composition according to the first aspect, the modified isocyanate composition according to the third aspect.

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

Preferably, the active hydrogen group-containing substance includes any one of a polyol, a polyamine, a polythiol, or a combination of at least two thereof.

Wherein the active hydrogen group-containing substance is a polyol, and the polymer is a polyurethane; the substance containing active hydrogen groups is polyamine, and the polymer is polyurea; the active hydrogen group-containing substance is polythiol, and the polymer is polythiourethane.

In a fifth aspect, the present invention provides a two-component polyurethane composition comprising an agent a and an agent B; the agent a comprises the isocyanate composition of the first aspect and/or the modified isocyanate composition of the third aspect; the agent B comprises an active hydrogen group-containing substance.

The two-component polyurethane composition is a two-component polyurethane composition comprising an isocyanate composition and/or a modified isocyanate composition and an active hydrogen group-containing substance as an agent A and an active hydrogen group-containing substance as an agent B, and can be applied to coating materials such as paints and adhesives, two-component curing sealing materials, potting agents and the like. Such a two-component polyurethane composition is a raw material in which an agent a (curing agent) and an agent B (main agent) which are separately prepared are compounded immediately before use.

The coating raw material is a two-component curing type resin raw material for forming a coating and comprises an agent A (curing agent) and an agent B (main agent). The coating may contain paint, adhesive, etc.

When a coating material is used as the coating material, exemplary uses include, but are not limited to: a coating material for plastics, a coating material for automobile exterior decoration, a coating material for automobile interior decoration, a coating material for electric/electronic materials, a coating material for optical materials (such as lenses), a coating material for building materials, a coating material for glass, a coating material for woodwork, a coating material for films, an ink coating material, a coating material (coating agent) for artificial leather, a coating material (coating agent) for cans, and the like.

Preferably, the agent a comprises a modified isocyanate composition, which is obtained by modification of the isocyanate composition, preferably comprising the group (a) isocyanurate groups and/or the group (d) urethane groups.

The agent A may further contain other aromatic isocyanate, aliphatic isocyanate, or araliphatic isocyanate, as required.

In the present invention, the agent a in the two-component polyurethane composition comprises 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 the effective factor of 3.70-4.70. Through the design and control of effective factors, the two-component polyurethane composition as a two-component polyurethane coating can effectively inhibit the discoloration of the coating, so that the coating can maintain excellent stability in a high-temperature and high-humidity environment, and the discoloration resistance of the coating is remarkably improved.

Preferably, the active hydrogen group in the agent B includes any one of a hydroxyl group, an amino group, a mercapto group (thiol group), or a combination of at least two thereof.

Preferably, the agent B comprises any one of a polyol (component containing at least 2 hydroxyl groups), a polythiol (component containing at least 2 mercapto groups/thiol groups), a polyamine (component containing at least 2 amino groups), or a combination of at least two thereof.

Preferably, the agent B comprises a polyol.

Preferably, the polyol comprises a low molecular weight polyol and/or a high molecular weight polyol.

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 (e.g., 80, 100, 150, 200, 250, 300, or 350, etc.).

Illustratively, the low molecular weight polyols include diols 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-cyclohexanediol, hydrogenated bisphenol A, 1, 4-dihydroxy-2-butene, 2, 6-dimethyl-1-octene-3, 8-diol, bisphenol A, and the like; examples of the polyhydric alcohol include trihydric alcohols such as glycerol and trimethylolpropane, tetrahydric alcohols such as tetramethylolmethane (pentaerythritol) and diglycerol, pentahydric alcohols such as xylitol, hexahydric alcohols such as sorbitol, mannitol, allitol, iditol, dulcitol, altritol, inositol and dipentaerythritol, heptahydric alcohols such as avocado sugar alcohol, and octahydric alcohols such as sucrose.

In addition, a polyalkylene oxide (a random and/or block copolymer containing at least 2 alkylene oxides) having a number average molecular weight of 60 to 400, which is obtained by adding an alkylene oxide such as ethylene oxide or propylene oxide to the above-mentioned alcohol as an initiator, is also contained in the low molecular weight polyol.

Preferably, the high molecular weight polyol is a compound containing at least 2 hydroxyl groups and having a number average molecular weight of 400 to 1000 (e.g., 500, 800, 1000, 2000, 3000, 4000, 5000, 6000, 7000, 8000, 9000, etc.); further preferably, the high molecular weight polyol has a number average molecular weight of 400 to 5000.

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

Illustratively, the polyether polyol includes: polyoxy (C2-C3) alkylene polyols, polytetramethylene ether glycol, polytrimethylene ether glycol, and the like. Among these, examples of the poly (C2-C3) alkylene oxide polyol include addition polymers (random and/or block copolymers containing at least 2 alkylene oxides) of C2-C3 alkylene oxides such as ethylene oxide and propylene oxide, which are obtained by using the above-mentioned low-molecular-weight polyol as an initiator. Specific examples of the poly (C2-C3) alkylene group include polyethylene glycol, polypropylene glycol, polyethylene-polypropylene copolymer, and the like. Examples of the polytetramethylene ether glycol include ring-opened polymers (polytetramethylene ether glycols) obtained by cationic polymerization of tetrahydrofuran, and amorphous polytetramethylene ether glycols obtained by copolymerizing the above-mentioned glycols with polymerized units of tetrahydrofuran. Further, plant-derived polytetramethylene ether glycol obtained by using tetrahydrofuran produced from a plant-derived raw material such as furfural as a starting material can be also mentioned. Examples of polytrimethylene ether glycol include a polyol produced by polycondensation of 1, 3-propanediol derived from a plant.

Illustratively, the polyester polyol includes: a polycondensate obtained by reacting the above-mentioned low-molecular-weight polyol (preferably a diol) with a polybasic acid (preferably a dibasic acid) under known conditions.

Examples of the polybasic acid include saturated aliphatic dicarboxylic acids (C11 to C13) such as oxalic acid, malonic acid, succinic acid, methylsuccinic acid, glutaric acid, adipic acid, 1-dimethyl-1, 3-dicarboxylpropane, 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, toluenedicarboxylic acid and naphthalenedicarboxylic 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 above carboxylic acids, such as oxalic anhydride, succinic anhydride, maleic anhydride, phthalic anhydride, 2-alkyl (C12 to C18) succinic anhydride, tetrahydrophthalic anhydride and trimellitic anhydride, and acid halides derived from these carboxylic acids, such as oxalyl dichloride, adipoyl dichloride and sebacoyl dichloride.

Examples of the polyester polyol include vegetable oil-based polyester polyols obtained by condensation reaction of the low molecular weight polyol described above with a vegetable oil fatty acid having a hydroxyl group (for example, a hydroxycarboxylic acid such as a castor oil fatty acid containing ricinoleic acid or a hydrogenated castor oil fatty acid containing 12-hydroxystearic acid) under known conditions.

Examples of the polyester polyol include those obtained by ring-opening polymerization of lactones such as e-caprolactone and y-valerolactone using the above-mentioned low-molecular-weight polyol (preferably diol) as an initiator, e.g., polycaprolactone polyols and polypentanolactone polyols, and lactone-based polyester polyols obtained by copolymerization of these with the above-mentioned diol.

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

Illustratively, the polyurethane polyol is obtained by reacting the polyester polyol, polyether polyol and/or polycarbonate polyol obtained in the above manner with the above polyisocyanate (containing HDI, hereinafter the same applies) at a ratio of an equivalent ratio of hydroxyl group to isocyanate group (OH/NCO) of more than 1, for example, polyester polyurethane polyol, polyether polyurethane polyol, polycarbonate polyurethane polyol, polyester polyether polyurethane polyol and the like.

As an example of the epoxy polyol, there may be mentioned an epoxy polyol obtained by reacting the above-mentioned low molecular weight polyol with a polyfunctional halohydrin such as epichlorohydrin or β -methyl epichlorohydrin.

As an example, the vegetable oil polyol includes, for example, a vegetable oil containing a hydroxyl group such as castor oil and coconut oil. Examples thereof include castor oil polyol, and ester-modified castor oil polyol obtained by reacting castor oil polyol with polypropylene polyol.

As an example, the polyolefin polyol includes, for example, polybutadiene polyol, partially saponified ethylene-vinyl acetate copolymer, and the like.

As an example, the acrylic polyol may be a copolymer obtained by copolymerizing a hydroxyl group-containing acrylate and a copolymerizable vinyl monomer copolymerizable with the hydroxyl group-containing acrylate.

Among them, examples of the hydroxyl group-containing acrylic ester include 2-hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, hydroxybutyl (meth) acrylate, 2-dihydroxymethylbutyl (meth) acrylate, polyhydroxyalkyl maleate, polyhydroxyalkyl fumarate, and the like. Preferred examples thereof include 2-hydroxyethyl (meth) acrylate and the like.

Examples of the copolymerizable vinyl monomer include alkyl (meth) acrylates (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, and the like, and aromatic vinyl monomers such as styrene, vinyltoluene and alpha-methylstyrene, vinyl cyanides such as (meth) acrylonitrile, carboxyl group-containing vinyl monomers such as (meth) acrylic acid, fumaric acid, maleic acid, itaconic acid, or alkyl esters thereof, for example, 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 tri (meth) acrylate and the like, for example, an isocyanate group-containing vinyl monomer such as 3- (2-isocyanate-2-propyl) - α -methylstyrene, and the like.

The acrylic polyol can be obtained by copolymerizing these hydroxyl group-containing acrylic ester and copolymerizable vinyl monomer in the presence of an appropriate solvent and a polymerization initiator.

The acrylic polyol may contain a polysiloxane polyol or a fluorine polyol.

For example, the polysiloxane polyol may be an acrylic polyol obtained by blending a vinyl group-containing polysiloxane compound such as γ -methacryloxypropyltrimethoxysilane as a copolymerizable vinyl monomer in the copolymerization of the above acrylic polyol.

For example, the fluorine polyol may be an acrylic polyol obtained by adding a fluorine compound containing a vinyl group such as tetrafluoroethylene or chlorotrifluoroethylene as a copolymerizable vinyl monomer to the copolymerization of the acrylic polyol.

Illustratively, the vinyl monomer-modified polyol can be obtained by reacting the above-mentioned high-molecular-weight polyol with the above-mentioned vinyl monomer such as alkyl (meth) acrylate.

The polyol component may be used alone or in combination of 2 or more.

If necessary, the agent B may be blended with a urethane catalyst, a hydrolysis preventing agent, an antifoaming agent, a surfactant, a slip imparting agent, a surface conditioning agent, an antioxidant, a weather resistant stabilizer, a pigment, a dye, a filler, a resin powder, etc. at an appropriate ratio.

Preferably, the two-component polyurethane composition is formed as a coating material by, for example, mixing the agent a and the agent B, applying the mixture to a coating object by a known method, and curing the mixture. Thereby, a coating material (coating layer) can be formed. Such a coating material is excellent in discoloration resistance.

As a preferred embodiment of the present invention, the two-component polyurethane composition forms a coating layer as a polyurethane coating material having excellent discoloration resistance, good color stability under high temperature and high humidity, and a color difference Δ b of the coating layer after a humid heat durability test (2000 h) is not more than 1.2, for example, Δ b may be 1.15, 1.1, 1.05, 1.0, 0.9, 0.8, 0.7, 0.6, 0.5, etc., and more preferably < 1.2.

Compared with the prior art, the invention has the following beneficial effects:

the isocyanate composition provided by the invention has excellent reactivity through the design and control of effective factors, and can be used for preparing high-performance polyurethane products. The isocyanate composition can effectively improve the stability of polyurethane products, particularly enables the polyurethane coating material to have excellent discoloration resistance, keeps excellent color stability in high-temperature and high-humidity environments, has the color difference delta b of the coating after a damp-heat durability test of 2000h less than or equal to 1.2, and obviously improves the yellowing resistance and appearance of the coating.

Drawings

FIG. 1 is a schematic flow diagram of a process for preparing the isocyanate composition in accordance with one embodiment of the present invention;

wherein, the method comprises the following steps of 10-phosgenation, 20-removal, 30-separation, 40-heavy component recovery and 50-refining.

Detailed Description

The technical solution of the present invention is further explained by the following embodiments. It should be understood by those skilled in the art that the examples are only for the understanding of the present invention and should not be construed as the specific limitations of the present invention.

The components and performance of the invention are tested as follows:

1. determination of the chlorine content by mass (value a) in the isocyanate composition: XRF testing

The instrument comprises the following steps: energy dispersive X-ray fluorescence spectroscopy (ED-XRF), type: MERAK-LE II;

the method comprises the following steps: standard addition method

Principle and operation: chromatographically pure CCl ₄ The standard substance is a Cl source, ethyl acetate is a diluent, the Cl element in the sample is excited by X rays generated by an X-ray light pipe to generate characteristic X-ray fluorescence, the characteristic X-ray fluorescence intensity and the element concentration are in a linear relation, a standard curve is drawn, and the extrapolated value is the Cl element content in the sample.

2. Determination of the mass content of chlorinated isocyanate (B value) in the isocyanate composition: GCMS test

The analysis was performed using gas chromatography-mass spectrometry under the following conditions, and the contents herein are normalized contents.

An analytical instrument: agilent 5977B GCMS

A chromatographic column: DB-5 chromatographic column with specification of 30m × 0.25mm × 0.25 μm

Temperature of the column box: maintaining at 50 deg.C for 2min, heating to 80 deg.C at 5mL/min, heating to 280 deg.C at 15mL/min, and maintaining for 10min

Separation ratio: without diversion

Sample inlet temperature: 280 deg.C

Detecting the temperature: 300 deg.C

Carrier gas: helium gas

Carrier gas flow: 1mL/min (constant flow)

Sample introduction amount: 1 μ L

The detection method comprises the following steps: SIM selected ion scan mode (for HDI selected ion 160/126, for PDI selected ion 146/112, for HMDI selected ion 254/220, for IPDI selected ion 214/180)

3. Determination of the mass percentage of isocyanate in the isocyanate composition: gas chromatography testing

The analysis was carried out by gas chromatography under the following conditions, and the contents herein are normalized contents.

An analytical instrument: agilent 7890B GC

A chromatographic column: DB-5 chromatographic column with specification of 30m × 0.25mm × 0.25 μm

Temperature of the column box: maintaining at 50 deg.C for 1min, heating to 300 deg.C at a speed of 10 deg.C/min, and maintaining for 5min

Separation ratio: 30:1

Sample inlet temperature: 280 deg.C

Detecting the temperature: 320 deg.C

Carrier gas: nitrogen gas

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

Sample introduction amount: 1 μ L

A detector: FID

In the following embodiments of the present invention, "part(s)" and "%" are based on mass unless otherwise specified.

Example 1

An HDI composition and a preparation method thereof, wherein the effective factor E of the HDI composition is 4.70, and a flow diagram of the preparation method is shown in figure 1, and the preparation method specifically comprises the following steps:

a phosgenation step: introducing preheated and vaporized 1, 6-hexamethylene diamine into a phosgenation reactor at the rate of 1000 parts by mass/h, introducing phosgene at the rate of 5112 parts by mass/h, wherein the feeding temperatures of two feed streams are 310 ℃, and the reaction liquid is obtained by chlorobenzene catching after the two feed streams pass through a reaction zone of the phosgenation reactor; wherein the feeding pressure of the 1, 6-hexamethylene diamine and the phosgene is 0.25MPa, and the absolute pressure of a reaction zone is 0.09MPa and is slightly lower than the atmospheric pressure; the molar ratio of phosgene to 1, 6-hexamethylenediamine feed was 6, the temperature in the reaction zone was 350 ℃, the flow rate was 70m/s, the average contact time was 2s and the Reynolds number was 5000. The outlet of the reactor is captured by cold chlorobenzene, and the temperature after capture is 140 ℃ to obtain reaction liquid; thus, 1, 6-hexamethylenediamine was reacted with phosgene to produce HDI, and a reaction product containing HDI was obtained.

A removing procedure: the reaction product obtained in the phosgenation step was continuously fed to a phosgene removing column and a solvent removing column, and subjected to phosgene removing treatment and solvent removing treatment, respectively, to thereby prepare 1440 parts by mass of a crude HDI product.

A separation process: and (3) continuously conveying the crude product obtained in the removing process to a short-range evaporator to obtain 1418.7 parts by mass of an intermediate product from which heavy components are removed and 21.3 parts by mass of a first-level heavy component.

Heavy component recovery process: continuously conveying the primary heavy component to a secondary short-range evaporator to obtain 14.3 parts by mass of a heavy component reclaimed material and 7.0 parts by mass of a residual heavy component; the heavy component recycled material can be obtained through multiple circulations of the short-path evaporator. Next, the intermediate product at a rate of 1418.7 parts by mass/h was mixed with the heavy component regrind at a rate of 14.3 parts by mass/h to obtain a mixture, i.e., the mass percentage content of the heavy component regrind in the mixture was 1%.

A refining step: continuously conveying the mixture into a rectifying tower at a speed of 1433 parts by mass/h, wherein the rectifying tower is filled with a filler with the number equivalent to 25 of a theoretical plate number, removing light components from the top of the tower in the rectifying tower, and extracting the HDI composition from the tower to obtain a target product;

the rectification conditions in the rectification column are as follows:

temperature at the bottom of the column: 120-130 deg.C

The tower top temperature: 80-100 deg.C

Pressure at the top of the column: 10-50PaA

Residence time: 2 to 3h

The reflux ratio of the tower top is as follows: 10

The extraction amount of the rectification procedure is as follows: 1329 parts by mass/h.

Thus, an HDI composition was obtained in which the mass content of HDI was > 99%, the mass content of chlorine (value A) was 22.2ppm, the mass content of chlorinated isocyanate CHI (value B) was 10ppm, and the effectiveness factor E was 4.70.

Examples 2 to 5, comparative examples 1 to 2

An HDI composition and a process for its preparation, the effective factor E of which is shown in table 1, respectively, and which process is identical to example 1 except for some of the process parameters, specifically shown in table 1 (the process/parameters not shown in table 1 are exactly the same as in example 1). In Table 1, "molar ratio of phosgene" means the molar amount of phosgene in the phosgenation step, based on 1mol of 1, 6-hexanediamine; the "heavy component recovered material ratio" represents the mass percentage content of the heavy component (recovered material) in the mixture in the heavy component recovery step.

TABLE 1

Examples 6 to 10, comparative examples 3 to 4

A PDI composition and a preparation method thereof, wherein the effective factor E of the PDI composition is shown in Table 2, and the flow of the preparation method is the same as that of example 1, except that part of process parameters are different, and are specifically shown in Table 2 (the process/parameters not shown in Table 2 are completely the same as that of example 1). In Table 2, "molar ratio of phosgene" means the molar amount of phosgene in the phosgenation step, based on 1mol of 1, 5-pentanediamine; the "heavies recycle ratio" refers to the mass percent of heavies (recycle) in the mixture during the heavies recycle step.

TABLE 2

Examples 11 to 15, comparative examples 5 to 6

An HMDI composition and a method for preparing the same, wherein the effective factor E of the HMDI composition is shown in Table 3, and the flow of the preparation method is the same as that of example 1, except that part of the process parameters are different, and are specifically shown in Table 3 (the process/parameters not shown in Table 3 are completely the same as that of example 1). In table 3, "molar ratio of phosgene" means the molar amount of phosgene in the phosgenation process based on 1mol of 4,4' -diaminodicyclohexylmethane; the "heavy component recovered material ratio" represents the mass percentage content of the heavy component (recovered material) in the mixture in the heavy component recovery step.

TABLE 3

Examples 16 to 20, comparative examples 7 to 8

An IPDI composition and a preparation method thereof, the effective factor E of the IPDI composition is respectively shown in Table 4, the flow of the preparation method is the same as that of example 1, the difference is only that part of the process parameters are different, and the process/parameters are specifically shown in Table 4 (the process/parameters not shown in Table 4 are completely the same as that of example 1). In Table 4, "molar ratio of phosgene" means the molar amount of phosgene in the phosgenation step, based on 1mol of isophoronediamine; the "heavy component recovered material ratio" represents the mass percentage content of the heavy component (recovered material) in the mixture in the heavy component recovery step.

TABLE 4

Examples 21 to 24 and comparative examples 9 to 12

HDI was prepared by the method of prior art CN101962348A, example 8, as comparative example 9, which is a thermal cracking process for preparing HDI, and the product contains no chlorine and no effective factor; the heavies recycle from example 1 was added to the product at a ratio of 4% (i.e., the resulting mixture had a weight percent of heavies of 4%) to yield example 21.

Similarly, PDI was prepared as comparative example 10 using the method of example 1 of prior art CN 114105825A; the heavies recycle from example 6 was added to the product at a ratio of 4% (i.e., the resulting mixture had a weight percent of heavies of 4%) to give example 22.

HMDI was prepared as comparative example 11 using the method of example 4 of prior art CN 101234998A; the heavies recycle from example 11 was added to the product at a ratio of 4% (i.e., the resulting mixture had a weight percent of heavies of 4%) to give example 23.

IPDI was prepared as comparative example 12 using the procedure of prior art CN114507161A, example 1; the heavies recycle from example 16 was added to the product at a ratio of 4% (i.e., the resulting mixture had a weight percent of heavies of 4%) to give example 24.

Application example

A two-component polyurethane composition, in particular to a two-component polyurethane coating material (paint), which comprises an agent A and an agent B.

Specifically, the application example provides 2 agents A, marked as agent A-1 and agent A-2, which are respectively matched with agent B to serve as a two-component polyurethane coating material; the formula is as follows:

(1) Preparation of agent A-1: 413.7 parts by mass of an HDI composition (37.7 parts by mass for a PDI composition, 39.9 parts by mass for an HMDI composition, and 39.9 parts by mass for an IPDI composition) and 36.7 parts by mass of trimethylolpropane were mixed and reacted at 70 ℃ for 6 hours under a nitrogen atmosphere; distilling the reaction solution obtained by the reaction with a thin film distillation apparatus to distill off unreacted isocyanate, thereby obtaining a modified isocyanate composition containing a urethane group obtained by reacting isocyanate with trimethylolpropane; the isocyanate compositions described above are the isocyanate compositions provided in examples 1 to 24 and comparative examples 1 to 12, respectively;

the polyisocyanate component (agent-1) was prepared by adding ethyl acetate to the modified isocyanate composition so that the solid content became 75wt.%, and the NCO group content in the polyisocyanate component was 11.6wt.%.

(2) Preparation of agent A-2: to 100 parts by mass of the 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) was added 2 parts by mass of 1, 3-butanediol, the temperature was raised to 75 ℃ under a nitrogen atmosphere, and a urethanization reaction was performed for 2 hours with an equivalent ratio (NCO/OH) of the isocyanate group in the isocyanate composition to the hydroxyl group of 1, 3-butanediol being 24; then, at the same temperature, a tetrabutylammonium hydroxide solution (37% methanol solution) was added as an isocyanuric acid esterification catalyst in an amount of 0.1phr (0.037 phr in terms of solid content), and the reaction was terminated after 4 hours; the obtained reaction solution was passed through a thin film distillation apparatus (temperature 150 ℃, vacuum degree 50 Pa) to remove unreacted isocyanate (distillation yield 60 wt.%), thereby obtaining a modified isocyanate composition; the modified isocyanate composition comprises isocyanurate groups of an isocyanate trimer; the isocyanate compositions described above are the isocyanate compositions provided in examples 1 to 24 and comparative examples 1 to 12, respectively;

ethyl acetate was added to the modified isocyanate composition so that the solid content became 75wt.%, to prepare a polyisocyanate component (agent a-2).

(3) Preparation of agent B: 40 parts of fluorine polyol (manufactured by DAIKIN INDUSTRIES LTD. ZEFFLE GK-570, hydroxyl value of solid content: 64mg KOH/g, butyl acetate as solvent), 52.5 parts of titanium oxide (manufactured by stone Productivity Co., ltd., CR 93), 33.8 parts of butyl acetate, and 110 parts of glass beads having a diameter of 2mm were stirred for 2 hours by a paint stirrer, then the glass beads were filtered off, and butyl acetate was added so that the solid content concentration became 58wt.% to obtain a B agent, wherein the titanium oxide ratio was 45wt.%.

(4) Preparing a two-component polyurethane coating material: the obtained agent a (agent a-1 or agent a-2) and agent B were mixed so that the equivalent ratio of isocyanate groups to hydroxyl groups (NCO/OH) became 1.0 to prepare a mixed solution, and butyl acetate was added to the mixed solution so that the NV value (coating film component mass, solid content) became 60wt.% to obtain the two-component polyurethane coating material.

Performance evaluation:

coating the two-component polyurethane coating material to be detected on the surface of a polyethylene terephthalate (PET) substrate, and heating at 120 ℃ for 2min for curing; the PET substrate coated with the mixed solution was cured at 60 ℃ for 2 days, thereby forming a coating layer having a thickness of about 15 μm on the PET substrate.

The weatherability of the coating (color difference of the coating in the damp heat test) was measured by the following method: the initial b value (b 1, initial value) of the coating was determined using a colorimeter (3nh NR10QC); then the sample coated with the coating is placed in a constant temperature and humidity apparatus (high-speed rail apparatus) and kept for 2000h under the conditions of 85 ℃ and 85% of relative humidity; measuring the b value (b 2) of the sample subjected to the damp heat durability test for 2000h in the same manner as the above, and calculating the color difference Δ b, Δ b = | b2-b1 | of the coating before and after the damp heat durability test; the results are shown in tables 5 to 8.

TABLE 5

TABLE 6

TABLE 7

TABLE 8

The combination of the performance test data shows that the effective factor of the isocyanate composition is controlled within the range of 3.70-4.70, so that the prepared two-component polyurethane coating material has excellent discoloration resistance, good color stability under high temperature and high humidity, and the color difference delta b of the coating after a damp-heat durability test (2000 h) is less than 1.2 and as low as 0.98-1.19.

The Applicant states that the present invention is illustrated by the above examples of isocyanate compositions of the invention and their preparation and use, but that the invention is not limited to the above process steps, i.e. it is not meant that the invention must rely on them for its implementation. It will be apparent to those skilled in the art that any modification of the present invention, equivalent substitutions of selected materials and additions of auxiliary components, selection of specific modes and the like, which are within the scope and disclosure of the present invention, are contemplated by the present invention.

Claims (10)

1. An isocyanate composition, wherein said isocyanate composition has an effective factor of from 3.70 to 4.70;

the calculation formula of the effective factor is shown as formula I:

wherein E is an effective factor;

a is the mass content of chlorine in the isocyanate composition;

b is the mass content of the chlorinated isocyanate in the isocyanate composition;

M _Cl is the relative atomic mass of chlorine;

M _B is the relative molecular mass of the chlorinated isocyanate.

2. The isocyanate composition according to claim 1, wherein the isocyanate is a diisocyanate, preferably comprising any one or a combination of at least two of pentamethylene diisocyanate, hexamethylene diisocyanate, dicyclohexylmethane diisocyanate, isophorone diisocyanate;

preferably, the mass percentage of the isocyanate in the isocyanate composition is more than or equal to 97 percent.

3. The isocyanate composition according to claim 1 or 2, wherein the substance corresponding to the effective factor comprises any one or a combination of at least two of the following compounds:

wherein R is a divalent group obtained by removing NCO groups in isocyanate;

preferably, R is selected from

Any one or a combination of at least two of; wherein the wavy line represents the attachment site of the group.

4. 4-isocyanate composition according to any one of claims 1 to 3, characterized in that the chlorinated isocyanate is a compound obtained by replacing one NCO group of an isocyanate by chlorine;

preferably, the chlorinated isocyanate comprises

Any one or a combination of at least two of them.

5. The isocyanate composition according to any one of claims 1 to 4, wherein A is obtained by X-ray fluorescence spectroscopy analysis;

preferably, said B is tested by chromatography-mass spectrometry, further preferably by gas chromatography-mass spectrometry.

6. A process for the preparation of an isocyanate composition according to any one of claims 1 to 5, comprising: and (3) reacting an amine compound with phosgene to obtain the isocyanate composition.

7. The method of claim 6, comprising the steps of:

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

(2) Removing the reaction product obtained in the step (1) to obtain a crude product; the removal treatment comprises a phosgene removal treatment and/or a solvent removal treatment;

(3) Sequentially separating and refining the crude product obtained in the step (2) to obtain the isocyanate composition;

preferably, the separation in the step (3) obtains heavy components and intermediate products; refining the mixture of the intermediate product and the heavy component to obtain the isocyanate composition; the mass percentage of the heavy components in the mixture is 1-10%;

preferably, the method of refining is rectification.

8. A modified isocyanate composition obtained by modifying the isocyanate composition according to any one of claims 1 to 5;

the modified isocyanate composition comprises any one or a combination of at least two of the groups (a) - (i): (a) isocyanurate groups, (b) uretdione groups, (c) biuret groups, (d) urethane groups, (e) urea groups, (f) iminooxadiazinedione groups, (g) allophanate groups, (h) uretonimine groups, (i) carbodiimide groups.

9. An isocyanate-based polymer, wherein the polymer is formed by reacting an isocyanate-based material with an active hydrogen group-containing material; the isocyanate-based material includes at least one of the isocyanate composition according to any one of claims 1 to 5 and the modified isocyanate composition according to claim 8.

10. A two-component polyurethane composition is characterized by comprising an agent A and an agent B;

the agent A comprises the isocyanate composition of any one of claims 1 to 5 and/or the modified isocyanate composition of claim 8;

the agent B comprises an active hydrogen group-containing substance;

preferably, the modified isocyanate composition comprises a group (a) isocyanurate groups and/or a group (d) urethane groups;

preferably, the agent B comprises a polyol.

Images