CN115746251A - Isocyanate composition, modified composition and polyurethane elastomer - Google Patents

Abstract

The invention provides an isocyanate composition, a modified composition and a polyurethane elastomer, wherein the effective factor of the isocyanate composition is 3.80-5.30, 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 improve the stability of a polyurethane product, particularly can remarkably improve the discoloration resistance and the weather resistance of a polyurethane elastomer, inhibit the color number growth and yellowing under the damp and hot condition, improve the tensile strength and the tearing strength of the polyurethane elastomer, and enable the polyurethane elastomer to have excellent comprehensive performance in the aspects of weather resistance, stability, mechanical properties and the like.

Description

Isocyanate composition, modified composition and polyurethane elastomer

Technical Field

The invention belongs to the technical field of isocyanate, and particularly relates to an isocyanate composition, a modified composition and a polyurethane elastomer.

Background

Polyurethane elastomers (PUR) have the characteristics of high elasticity, high strength, wide hardness range, good abrasion resistance and the like, and are applied to the industries of automobile industry, mechanical industry, medical industry, transportation, sports goods, electronic industry, chemical industry, coal and the like. The polyurethane elastomer can be classified into TDI (toluene diisocyanate) type, MDI (diphenylmethane diisocyanate) type, PPDI (phenylene diisocyanate) type, NDI (naphthalene diisocyanate) type, CHDI (cyclohexane diisocyanate) type, etc., depending on the isocyanate used, and TDI type and MDI type are most common.

With the expansion of the application range of polyurethane elastomers, the common TDI type PUR and MDI type PUR can not meet the use requirements, and people develop a new polyurethane elastomer to improve the performance of the elastomer. For example, CN113354788A discloses a polyurethane elastomer with good heat resistance and slip resistance, which is prepared from the following raw materials: 60-65% of polyester polyol, 30-33% of diisocyanate and 1-9.5% of mixed chain-extending cross-linking agent, wherein the diisocyanate comprises a combination of dimethyl diphenyl diisocyanate, p-phenylene diisocyanate and 1, 5-naphthalene diisocyanate. CN104017166A discloses a preparation method of a high temperature resistant thermoplastic polyurethane elastomer, which comprises the following steps: adding an antioxidant, a catalyst and molten polyester polyol into a reaction kettle, and dehydrating under the conditions of heating and decompression to form a component A; heating and melting diisocyanate to form a component B; uniformly mixing molten trihydric alcohol and molten dihydric alcohol, and dehydrating under reduced pressure and heating conditions to form a component C; adding the component A, the component B and the component C into a double-screw extruder at the same time, and carrying out stepwise polymerization reaction to obtain a high-temperature-resistant thermoplastic polyurethane elastomer; the diisocyanate is a mixture of 70-100% of trans-1, 4-CHDI and 0-30% of cis-1, 4-CHDI. CN104817683A discloses a polyurethane elastomer with good mechanical property and fatigue resistance, the raw materials of which comprise component A and component B, the component A comprises the following components in parts by weight: 100 parts of macromolecular diol, 5-20 parts of NDI,10-30 parts of p-phenylene diisocyanate or 10-50 parts of 3,3 '-dimethyl-4, 4' -biphenyl diisocyanate (TODI); the component B is as follows: 0-100 parts of macromolecular dihydric alcohol, 8-30 parts of chain extender and 0.02-0.5 part of catalyst; the weight ratio of the component A to the component B is 100 (8-30).

Compared with common MDI and TDI, the NDI, PPDI and CHDI have higher melting points and belong to high-melting-point isocyanate, and the NDI and PPDI have aromatic structures and larger steric hindrance effect, so that the synthesized polyurethane elastomer has the characteristics of high hardness, good rebound resilience, good heat resistance, excellent dynamic performance, good wear resistance and the like, can be suitable for high dynamic load scenes, and is a popular isocyanate raw material in the preparation of novel polyurethane elastomers. However, despite the various advantages of NDI, PPDI, CHDI, they also present non-negligible disadvantages: due to the high reactivity of the NCO groups, an unnecessary increase in the color number, i.e., significant yellowing, and poor weatherability may be caused in the production of polyurethane, thereby seriously affecting the appearance and product quality of the polyurethane elastomer.

Therefore, there is a need in the art to develop an isocyanate raw material with better performance to improve the properties of the polyurethane elastomer, such as weather resistance and appearance.

Disclosure of Invention

In view of the defects of the prior art, the invention aims to provide an isocyanate composition, a modified composition and a polyurethane elastomer, wherein the isocyanate composition can effectively inhibit the color number of the polyurethane elastomer from increasing under the damp and hot conditions through the design of effective factors, obviously improve the stability and weather resistance of the polyurethane elastomer and improve the mechanical properties of the polyurethane elastomer.

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 3.80 to 5.30.

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, about 35.5;

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

The isocyanate compositions provided herein have an effective factor E of from 3.80 to 5.30, which may be, for example, 3.90, 4.00, 4.10, 4.30, 4.50, 4.70, 4.90, 5.00, 5.10 or 5.20, and the specific values therebetween, are not intended to be exhaustive or to limit the invention to the precise values encompassed by the stated ranges for brevity.

In the present invention, the isocyanate composition comprises a combination of isocyanate and chlorine-containing material, and is thus named as "isocyanate composition"; the chlorine-containing substance comprises a combination of chlorinated isocyanate and a substance corresponding to an effective factor. The isocyanate composition comprises a specific content and a specific type 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. Particularly, the isocyanate composition is used in polyurethane products, especially polyurethane elastomers, and can remarkably improve the stability and weather resistance of the polyurethane elastomers, inhibit color number growth and yellowing under the wet and hot conditions, improve the tensile strength and tear strength of the polyurethane elastomers, and enable the polyurethane elastomers to have excellent comprehensive performance in the aspects of weather resistance, stability, mechanical properties, appearance and the like.

Preferably, the isocyanate is diisocyanate, and further preferably includes any one of Naphthalene Diisocyanate (NDI), benzene diisocyanate (PPDI), cyclohexane diisocyanate (CHDI), diphenylmethane diisocyanate (MDI), toluene Diisocyanate (TDI), or a combination of at least two thereof.

In the present invention, unless otherwise specified, the isocyanate exemplified includes all isomers thereof, for example, the Naphthalene Diisocyanate (NDI) is

The phenylene diisocyanate (PPDI) is

The cyclohexane diisocyanate (CHDI) is

The diphenylmethane diisocyanate (MDI) is

The Toluene Diisocyanate (TDI) is

Preference is given to

Preferably, the naphthalene diisocyanate is 1, 5-naphthalene diisocyanate

The phenylene diisocyanate is 1, 4-phenylene diisocyanate (p-phenylene diisocyanate,

) (ii) a The cyclohexane diisocyanate is 1, 4-cyclohexane diisocyanate

The diphenylmethane diisocyanate is 4,4' -diphenylmethane diisocyanate

The toluene diisocyanate is 2, 4-toluene diisocyanate

And/or 2, 6-toluene diisocyanate

Preferably, the isocyanate content in the isocyanate composition is more than or equal to 97% by mass, such as 97.5%, 98%, 98.5%, 99%, 99.1%, 99.2%, 99.3%, 99.4%, 99.5%, 99.6%, 99.7%, 99.8%, 99.9%, 99.92%, 99.95%, 99.98%, 99.99%, etc., more preferably more than or equal to 99%, and still more preferably more than 99%.

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

Preferably, the chlorinated isocyanate comprises

(preferred is

Chloronaphthyl isocyanate CNI, isocyanate NDI),

(chlorophenyl isocyanate CPPI, isocyanate PPDI),

(chlorocyclohexyl isocyanate CCHI, isocyanates CHDI),

(preferred is

Chlorodiphenylmethane isocyanate, isocyanate being MDI),

(preferred is

Chlorotoluene isocyanate and TDI) or the combination of at least two of the chlorotoluene isocyanate and the TDI).

As used herein, the expression of a "-" underlined loop structure refers to any position on the loop structure at which a linking site can be bonded.

Preferably, the isocyanate composition has a mass content of chlorinated isocyanate (B value) of 5-2000ppm, such as 10ppm, 20ppm, 30ppm, 50ppm, 80ppm, 100ppm, 300ppm, 500ppm, 700ppm, 900ppm, 1000ppm, 1100ppm, 1300ppm, 1500ppm, 1700ppm or 1900ppm, and the specific values therebetween are not exhaustive and for the sake of brevity, and the invention does not further include the specific values included in the range, and more preferably 10-1500ppm.

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.

Preferably, the substance corresponding to the effective factor comprises any one of the following compounds 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

(isocyanate is NDI),

(the isocyanate is PPDI),

(isocyanates are CHDI),

(isocyanates are MDI),

(preferred is

Isocyanate is TDI) or a combination of at least two thereof; wherein the wavy line represents the attachment site of the group.

Preferably, the isocyanate composition has a chlorine content (value a) of 1 to 1000ppm, for example, 2ppm, 5ppm, 8ppm, 10ppm, 30ppm, 50ppm, 80ppm, 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, and the invention is not intended to be exhaustive and to include specific values within the stated ranges, more preferably 5 to 500ppm.

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

Preferably, in formula I for calculating the effective factor, B is the mass content of the chlorinated isocyanate in the isocyanate composition, measured by chromatography-mass spectrometry, preferably by gas chromatography-mass spectrometry (GCMS).

In the research of the invention, the characterization method of the chlorine content in the isocyanate known in the prior art is difficult to accurately control the performance of the isocyanate, so that the performance of the polyurethane product/polyurethane elastomer, especially the yellowing resistance, the stability, the appearance and the like, cannot be effectively controlled. Specifically, the test method of 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 content of hydrolytic chlorine is measured 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 the isocyanate, and also comprises bromine with higher activity, and part of monochloro isocyanate can be hydrolyzed. The chlorine (and also a proportion of bromine) content measured in GB/T12009.1-1989 or GB/T12009.2-2016 does not provide an accurate indication of the isocyanate composition and hence of the effective control of the properties of isocyanates, polyurethane articles, and particularly polyurethane elastomers.

As a preferred technical scheme of the invention, 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 polychlorides and partial hydrolytic chlorine (not containing hydrolytic chlorine of monochloro-isocyanate) in the isocyanate composition, and correspondingly has finer and more definite chlorine content, and the partial chlorine content plays a key role in the activity of isocyanate and the performance of polyurethane products (such as polyurethane elastomers), thereby realizing the performance regulation and control of the isocyanate composition, further improving the performance of the polyurethane elastomers prepared by the effective factor E, and particularly having obvious improvement effects on weather resistance, stability, mechanical properties and appearance.

In the present invention, the chlorinated isocyanate and the substance corresponding to the effective factor may be produced as a by-product in the production process of 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.

It should be noted that when the isocyanation reaction is carried out using a diamine and phosgene, a specific efficiency factor can be obtained by preferably selecting the following parameters. The effective factor E of the isocyanate composition can also be adjusted by adding to the isocyanate a chlorinated isocyanate and/or a substance corresponding to the effective factor.

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 embodiment of the present invention, the component to be refined is a mixture of the intermediate product and the heavy component, the mass percentage of the heavy component in the mixture is 1 to 10%, for example, 2%, 3%, 4%, 5%, 6%, 7%, 8% or 9%, and specific values between the above values, which are limited by space and for simplicity, are not exhaustive, and are further preferably 2 to 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 reclaimed materials 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 ends recyclate in the isocyanate composition is between 1 and 10% (e.g. 2%, 3%, 4%, 5%, 6%, 7%, 8% or 9%, etc.), more preferably between 1 and 5%.

As a preferred technical scheme of the invention, the preparation method of the isocyanate composition is a phosgenation method, namely, an amine compound reacts with phosgene 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 gas phase phosgenation; a method of reacting diamine with phosgene in a liquid phase, which is also called a liquid phase phosgenation method or a cold-hot two-stage phosgenation method; a method of reacting diamine salts (e.g., diamine hydrochloride) with phosgene in a solvent, also known as phosgenation of diamine hydrochloride, is further preferred in the present invention to be a cold and hot two-stage phosgenation.

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

Preferably, step (1) specifically comprises: mixing diamine and a solvent to obtain an amine solution; and introducing phosgene into the amine solution to react to obtain a reaction product, namely a reaction solution containing diisocyanate.

Preferably, the 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 solvents may be used alone or in combination of at least two.

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

Preferably, the diamine is present in the amine solution in an amount of 1-50wt.%, for example, 2wt.%, 5wt.%, 8wt.%, 10wt.%, 12wt.%, 15wt.%, 18wt.%, 20wt.%, 22wt.%, 25wt.%, 28wt.%, 30wt.%, 35wt.%, 40wt.%, 45wt.%, or 48wt.%, and the specific values therebetween are not exhaustive, and for brevity, the invention does not provide for the specific values to be included in the ranges, and more preferably 5-40wt.%.

Preferably, in step (1), the molar ratio of phosgene to amine compound (diamine) is (3-50): 1, and can be, for example, 4.

Preferably, the reaction of step (1) comprises a cold reaction and a hot reaction which are carried out sequentially.

Preferably, the temperature of the cold reaction is-10 ℃ to 80 ℃, for example, it may be-5 ℃,0 ℃,5 ℃,10 ℃, 15 ℃,20 ℃, 25 ℃,30 ℃, 35 ℃,40 ℃, 45 ℃,50 ℃, 55 ℃, 60 ℃, 65 ℃, 70 ℃ or 75 ℃, and the specific values therebetween are limited by space and in the interest of brevity, the invention is not exhaustive list of the specific values included in the range, and further preferably 0 to 70 ℃.

Preferably, the cold reaction time is 1-20h, for example, 2h, 3h, 4h, 5h, 6h, 7h, 8h, 9h, 10h, 11h, 12h, 13h, 14h, 15h, 16h, 17h, 18h or 19h, and the specific values therebetween are not exhaustive, and for the sake of brevity, the invention does not provide an exhaustive list of specific values included in the range, and further preferably 2-15h.

Preferably, the temperature of the thermal reaction is 70 to 150 ℃, for example, it may be 75 ℃, 80 ℃, 85 ℃, 90 ℃, 95 ℃, 100 ℃, 105 ℃, 110 ℃, 115 ℃, 120 ℃, 125 ℃, 130 ℃, 135 ℃, 140 ℃ or 145 ℃, and specific values therebetween, for reasons of brevity and conciseness, the present invention is not exhaustive enumeration of specific values included in the range, further preferably 80 to 130 ℃.

Preferably, the thermal reaction time is 1 to 20h, for example, 2h, 3h, 4h, 5h, 6h, 7h, 8h, 9h, 10h, 11h, 12h, 13h, 14h, 15h, 16h, 17h, 18h or 19h, and specific values therebetween, which are not limited by space and for the sake of brevity, the present invention does not exhaustive list specific values included in the range, and further preferably 2 to 15h.

Preferably, the reaction of step (1) is carried out under normal pressure or under pressure.

Preferably, the pressure (gauge pressure) of the reaction in step (1) is 0 to 0.6MPa G, and may be, for example, 0.0005MPa G, 0.001MPa G, 0.003MPa G, 0.01MPa G, 0.02MPa G, 0.03MP a G, 0.05MPa G, 0.07MPa G, 0.09MPa G, 0.1MPa G, 0.2MPa G, 0.3MPa G, 0.4MPa G or 0.5MPa G, and specific values therebetween, for reasons of space and brevity, the present invention is not exhaustive and does not list specific values included in the range, further preferably 0.005 to 0.4MPa G, further preferably 0.01 to 0.2MPa G.

Preferably, the reaction (isocyanation step) in step (1) is a batch step or a continuous step, preferably a continuous step.

The continuous step is a step of continuously transferring a slurry (amine solution) in a stirring tank from the stirring tank to a reaction tank different from the stirring tank, reacting diamine and phosgene in the reaction tank, and continuously taking out an obtained reaction product (diisocyanate-containing reaction liquid) from the reaction tank. The number of reaction kettles in the continuous process is not particularly limited, and may be, for example, 2, 3, 4, 5 or more.

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 removing treatment in the step (2) is carried out in a phosgene removing 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 column, further preferably short path evaporator.

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 preferable technical scheme of the invention, the heavy component obtained by separation contains chlorine-containing substances with rich types and high content, the heavy component obtained by separation or a heavy component reclaimed material obtained by re-separation of the heavy component is mixed into an intermediate product (light component) obtained by separation according to a certain proportion and then is 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 3.80-5.30.

Preferably, the mass percentage of the heavy components (heavy component recyclates) in the mixture (materials involved in the refining) is between 1 and 10%, more preferably between 2 and 10%, so that the isocyanate composition has an effective factor of between 3.80 and 5.30. If the incorporation amount of the heavy component (heavy component recovery material) is too small, the effective factor is higher, and the reaction rate of the isocyanate composition is too high when the isocyanate composition is used for preparing the polyurethane elastomer, so that the polymerization is not uniform, the mechanical property of the polyurethane elastomer is poor, and the tensile strength and the tear strength are reduced; if the incorporation amount of the heavy component (heavy component recovery material) is too high, which results in too low effective factor, the isocyanate composition contains more impurities, so that the weather resistance of the polyurethane elastomer is poor, and particularly, the polyurethane elastomer has obvious yellowing phenomenon under the damp-heat condition.

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 method of refining 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 40, and may be, for example, 3, 5, 8, 10, 12, 15, 18, 20, 22, 25, 28, 30, 32, 35 or 38, and specific values therebetween, for reasons of space and brevity, the present invention is not exhaustive list of specific values included in the range, and more preferably 5 to 20.

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 40, 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 or 38, and specific values therebetween, and the invention is not exhaustive and for simplicity, and the specific values included in the range are more preferably 0.1 to 20.

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

(1) A phosgenation step: mixing diamine and a solvent to obtain an amine solution; introducing phosgene into the amine solution for reaction to obtain a reaction product; the reaction comprises a cold reaction and a hot reaction which are carried out in sequence, wherein the temperature of the cold reaction is less than that of the hot reaction;

(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 heavy components to obtain a mixture; the mass percentage of the heavy components in the mixture is 1-10%; or, performing 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 production method is shown in fig. 1, and includes a phosgenation step 10, a removal step 20, a separation step 30, a heavy component recovery step 40, and a purification step 50. The phosgenation step may be carried out in a batch manner or a continuous manner, and the continuous manner may be carried out in a continuous manner in a tank manner. The effective factor of the isocyanate composition is adjusted by properly adjusting the mixing ratio of the heavy components and the intermediate products, the supply ratio of phosgene, the reaction temperature, the reaction pressure, the average residence time, the reflux ratio of the rectifying tower and the like, and the control of the effective factor is mainly realized by the ratio of the heavy components and the intermediate products.

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

(1) A phosgenation step: continuously conveying amine solution containing NDA (naphthalene diamine) to a phosgenation reaction kettle by adopting a kettle type reaction with three or four continuous kettles, and continuously introducing phosgene into the tops of a cold reaction first kettle, a hot reaction first kettle and a hot reaction second kettle in an inserting tube manner according to the proportion; then, while maintaining the inside of the cold reaction kettle at the temperature and the reaction pressure of the cold reaction, stirring and mixing the amine solution and the phosgene; thus, NDA and phosgene (carbonyl chloride) are subjected to cold reaction to obtain cold reaction photochemical liquid;

then, continuously conveying the cold reaction photochemical liquid to the top of the hot reaction kettle; namely, continuously supplying an amine solution and phosgene to a cold reaction kettle, continuously taking out cold reaction photochemical liquid from the cold reaction kettle, and conveying the cold reaction photochemical liquid to a hot reaction kettle;

next, maintaining the interior of the thermal reaction kettle at the temperature and the reaction pressure of the thermal reaction, stirring and mixing the reaction substance and phosgene in the thermal reaction kettle, and carrying out phosgenation reaction; similarly, the second thermal reaction kettle carries out phosgenation reaction while inputting reaction substances;

thus, the phosgenation step was continuously performed to obtain a reaction solution containing NDI.

(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 crude NDI product.

(3a) A separation process: and (3) separating the NDI 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 first-stage heavy component is recycled through a short-range evaporator to obtain a heavy component recycled material and residual heavy components, and the heavy component recycled material and the residual heavy components 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, under the above-mentioned rectification conditions (bottom temperature, top pressure, bottom reflux ratio, top reflux ratio, residence time), the low boiling components are distilled off from the intermediate product, and the NDI composition is extracted from the middle part of the column.

Thus, NDI compositions comprising NDI, CNI and substances corresponding to the effective factors can be continuously produced.

In a third aspect, the present invention provides a modified isocyanate composition obtained by modifying the isocyanate composition according to the first aspect; the modifying composition comprises any one of 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 composition; the modified composition is suitably used as a polyisocyanate component and an active hydrogen group-containing substance as a raw material of an isocyanate-based polymer such as a polyurethane resin.

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

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

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

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

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

The modified 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 iminooxadiazinedione catalyst to subject the isocyanate to iminooxadiazinedione reaction (e.g., trimerization).

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

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

In a fourth aspect, the present invention provides an isocyanate-based polymer obtained by reacting an isocyanate-based substance with an active hydrogen group-containing substance; the isocyanate-based material includes at least one of the isocyanate composition according to the first aspect and the modified 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 isocyanate-based polymer is a polyurethane; the substance containing active hydrogen groups is polyamine, and the isocyanate-based polymer is polyurea; the active hydrogen group-containing substance is polythiol, and the isocyanate-based polymer is polythiourethane.

In a fifth aspect, the present invention provides a polyurethane elastomer, wherein the polyurethane elastomer is prepared from raw materials including an isocyanate and a polyol; the isocyanate-based material comprises the isocyanate composition according to the first aspect and/or the modified composition according to the third aspect.

Preferably, the polyol is a high molecular weight polyol.

Preferably, the preparation raw material further comprises a chain extender.

Preferably, the chain extender comprises a low molecular weight polyol and/or a low molecular weight polyamine.

In the present invention, the polyurethane elastomer (PUR) may be a thermoplastic polyurethane elastomer (TPU), a thermosetting polyurethane elastomer (TSU), a millable polyurethane elastomer, or the like. The polyurethane elastomer includes a soft segment formed by the reaction of an isocyanate-based substance with a polyol (high molecular weight polyol), and a hard segment formed by the reaction of an isocyanate-based substance with a chain extender (low molecular weight polyol and/or low molecular weight polyamine). The polyurethane elastomer can be produced by the reaction of an isocyanate-based substance, a high-molecular-weight polyol (active hydrogen group-containing substance), a low-molecular-weight polyol and/or a low-molecular-weight polyamine (active hydrogen group-containing substance). Namely, an isocyanate-based material (the isocyanate composition and/or the modified composition), a polyol (a high-molecular-weight polyol), and a chain extender (a low-molecular-weight polyol and/or a low-molecular-weight polyamine) are raw materials for producing the polyurethane elastomer.

In the invention, the isocyanate substance comprises the isocyanate composition and/or the modified composition, the effective factor of the isocyanate composition is 3.80-5.30, and the modified composition is obtained by modifying the isocyanate composition with the effective factor of 3.80-5.30. According to the invention, through the design and control of effective factors, the discoloration of the polyurethane elastomer can be effectively inhibited, the tensile strength and the tear strength of the polyurethane elastomer are improved, and the polyurethane elastomer shows excellent comprehensive properties in the aspects of discoloration resistance, weather resistance, stability, mechanical properties and the like.

Preferably, the polyol is a high molecular weight polyol, exemplary including but not limited to: any one or a combination of at least two of polyester polyol, polycarbonate polyol and polyether polyol, and polyester polyol is more preferred.

Preferably, the polyester polyol includes polycaprolactone polyol and/or adipic acid-based polyester polyol (polyester polyol having adipic acid as a polybasic acid), and further preferably adipic acid-based polyester polyol.

Preferably, the polyether polyol comprises polytetramethylene ether glycol.

Preferably, the chain extender comprises a low molecular weight polyol and/or a low molecular weight polyamine, further preferably a low molecular weight polyol.

Preferably, the low molecular weight polyol comprises ethylene glycol and/or 1, 4-butanediol, further preferably 1, 4-butanediol.

In the present invention, the polyurethane elastomer can be prepared by a one shot method or a prepolymer method, which is known in the art.

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

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

As for the method for producing the polyurethane elastomer, polymerization methods known in the art, such as bulk polymerization, solution polymerization, and the like, can be used.

In addition, in the production of the polyurethane elastomer, a known urethanization catalyst such as an amine or an organic metal compound (for example, an organotin compound, preferably dibutyltin dichloride, tin octylate, etc.) may be added to the raw materials for the production, if necessary.

If necessary, a plasticizer, an anti-blocking agent, a heat stabilizer, a light stabilizer, an ultraviolet absorber, a NOx yellowing inhibitor, an antioxidant, a mold release agent, a pigment, a dye, a lubricant, a nucleating agent, a filler, a hydrolysis inhibitor, and the like may be blended in the polyurethane elastomer at an appropriate ratio.

In a preferred embodiment of the present invention, the polyurethane elastomer is excellent in discoloration resistance and weather resistance, and also excellent in mechanical properties (tensile strength and tear strength).

In particular, the color difference Δ b of the polyurethane elastomer after 240h of the wet heat aging test under xenon lamp irradiation is less than or equal to 3.0, for example, Δ b may be 2.95, 2.9, 2.85, 2.8, 2.75, 2.7, 2.65, 2.6, 2.55, 2.5, 2.45, 2.4, 2.35, 2.3, 2.25, 2.2, 2.15, 2.1, 2.05, 2.0, 1.9, 1.8, 1.7, 1.6, 1.5, etc., and is more preferably less than 3.0.

Preferably, the tensile strength of the polyurethane elastomer prepared by the NDI composition is more than 41MPa and can reach 41.3-42.5MPa; the tearing strength is more than 64kN/m and can reach 64.1-65.2kN/m.

Preferably, the tensile strength of the polyurethane elastomer prepared by the PPDI composition is more than 44MPa and can reach 44.3-45.7MPa; the tearing strength is more than 119kN/m and can reach 119.6-121.6kN/m.

Preferably, the tensile strength of the polyurethane elastomer prepared from the CHDI composition is more than 35MPa, and can reach 35.1-36.1MPa; the tearing strength is more than or equal to 59kN/m and is 59.0-60.1kN/m.

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 a polyurethane product, particularly can remarkably improve the color change resistance and weather resistance of a polyurethane elastomer, inhibit color number increase and yellowing under a damp and hot condition, enable the color difference delta b of the polyurethane elastomer after a damp and hot aging test for 240 hours under irradiation of a xenon lamp to be less than 3.0, improve the tensile strength and tear strength of the polyurethane elastomer, and enable the polyurethane elastomer to have excellent comprehensive performance in the aspects of weather resistance, mechanical strength and the like.

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 described below by way of specific 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 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 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: not divided into

Sample inlet temperature: 280 deg.C

And (3) 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 Selective ion Scan mode (for NDI Selective ion 202/168, for PPDI Selective ion 152/118, for CHDI Selective ion 158/124)

2. 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.

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

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 60 deg.C for 1min, heating to 280 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 NDI composition and a preparation method thereof, wherein the effective factor E of the NDI composition is 5.30, 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: 800 parts by mass of chlorobenzene were charged into a cold reaction kettle, the temperature in the cold reaction kettle was adjusted to 20 ℃ and the pressure (gauge pressure) was adjusted to 0.04MPaG. Continuously charging a chlorobenzene solution of amine with the concentration of 10.0wt.% of 1,5-NDA (1, 5-naphthalene diamine) into a cold reaction kettle at the speed of 500 parts by mass/h, and continuously introducing phosgene into the kettle at the speed of 626 parts by mass/h, wherein the cold reaction temperature is 20 ℃ and the time is 2.5h, so as to obtain cold reaction photochemical liquid;

and (2) taking the cold reaction photochemical liquid out of the cold reaction kettle, conveying the cold reaction photochemical liquid to the hot reaction kettle, introducing phosgene into the hot reaction kettle at the mass part/h rate, maintaining the temperature in the hot reaction kettle at 110 ℃, adjusting the pressure (gauge pressure) to be 0.2MPa G, carrying out thermal reaction at the temperature of 110 ℃ for 4h, thus reacting the 1,5-NDA with the phosgene to generate the 1,5-NDI, and preparing a reaction product containing the 1, 5-NDI.

A removing procedure: the reaction product obtained in the phosgenation step was continuously transferred to a phosgene removal column and a solvent removal column, and subjected to phosgene removal treatment and solvent removal treatment, respectively, to prepare 130 parts by mass of a crude NDI product.

A separation process: and continuously conveying the crude product obtained in the removing process to a short-path evaporator to obtain an intermediate product 117.2 parts by mass and a first-level heavy component 12.8 parts by mass, wherein the heavy components are removed.

Heavy component recovery process: and continuously conveying the primary heavy component to a secondary short-range evaporator to obtain 2.39 parts by mass of a heavy component reclaimed material and 10.4 parts by mass of residual heavy component. Next, the intermediate product at a rate of 117.2 parts by mass/h was mixed with the heavy ends regrind at a rate of 2.39 parts by mass/h to obtain 119.6 parts by mass/h of a mixture, i.e., the mass percentage of the heavy ends regrind in the mixture was 2%.

A refining step: continuously conveying the mixture into a rectifying tower, filling the rectifying tower with a filler with the number equivalent to 5 of theoretical plates, removing light components from the top of the tower in the rectifying tower, and extracting an NDI 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: 130-140 deg.C

The tower top temperature: 120-130 deg.C

Pressure at the top of the column: 0-50PaA

Residence time: 2 to 4h

Reflux ratio at the top of the column: 4

Thus, the NDI composition was obtained, in which the mass content of NDI was > 99%, the mass content of chlorine (A value) was 7.6 ppm, the mass content of chlorinated isocyanate CNI (B value) was 15ppm, and the effective factor E was 5.30.

Examples 2 to 5, comparative examples 1 to 2

An NDI composition and a preparation method thereof, wherein the effective factor E of the NDI composition is respectively shown in Table 1, 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 1 (the process/parameters which are not shown in the Table 1 are completely the same as those of example 1). In Table 1, "molar ratio of phosgene" means the molar amount of phosgene in 1mol of 1,5-NDA in the phosgenation step; the "heavies recycle ratio" refers to the mass percent of heavies (recycle) in the mixture during the heavies recycle step.

TABLE 1

Examples 6 to 10, comparative examples 3 to 4

A PPDI composition and its preparation method, the effective factor E of the PPDI composition is shown in Table 2, the flow of its preparation method is the same as example 1, the difference is only that some process parameters are different, specifically shown in Table 2 (the process/parameter not shown in Table 2 is completely the same as example 1). In Table 2, "molar ratio of phosgene" means the molar amount of phosgene in the phosgenation process based on 1, 4-diaminobenzene as 1 mol; 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

A CHDI composition and a preparation method thereof, wherein the effective factor E of the PPDI composition is respectively shown in Table 3, the flow of the preparation method is the same as that of example 1, and only part of the process parameters are different and are specifically shown in Table 3 (the process/parameters which are 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 1mol of 1, 4-diaminocyclohexane in the phosgenation step; the "heavies recycle ratio" refers to the mass percent of heavies (recycle) in the mixture during the heavies recycle step.

TABLE 3

Examples 16 to 18 and comparative examples 7 to 9

NDI was prepared as comparative example 7 by the method of prior art CN110256296A, example 1, which is a thermal cracking method for preparing NDI, 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 give example 16.

Similarly, using the method in example 1 of CN110256296A, the raw material NDA was replaced with PPDA, and other conditions were identical, PPDI was prepared as comparative example 8; 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 17.

CHDI was prepared as comparative example 9 using the method of CN110256296A in example 1, substituting the starting material NDA with CHDA, and the other conditions were the same; 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 18.

Application example

A polyurethane elastomer, specifically a thermoplastic polyurethane elastomer (TPU), is prepared from isocyanate (polyisocyanate component), high molecular weight polyol, and chain extender (low molecular weight polyol); the isocyanate-based materials were the isocyanate compositions provided in examples 1 to 15 and comparative examples 1 to 6, respectively, the high molecular weight polyol was an adipic acid-based polyester polyol (manufactured by mitella co chemical corporation, number average molecular weight 2000), and the chain extender was 1, 4-butanediol (enokay reagent); in addition, the starting materials for the preparation also included a catalyst (tin octoate) and a heat-resistant stabilizer (available from Ciba Specialty Chemicals, IRGANOX 245).

The preparation method of the polyurethane elastomer comprises the following steps:

(1) A four-necked flask equipped with a stirrer, a thermometer, a reflux tube and a nitrogen supply line was charged with 221 parts by mass of the NDI composition (168 parts by mass for the PPDI composition and 175 parts by mass for the CHDI composition) and 531.2 parts by mass of the adipic acid-based polyester polyol, and reacted at 80 ℃ under a nitrogen atmosphere until the NCO group content became 9.1wt.% to obtain a prepolymer having an isocyanate group at the molecular end.

(2) Adding 3.9 parts by mass of a heat-resistant stabilizer and 0.07 part by mass of a solution obtained by diluting a catalyst tin octylate to 4wt.% with diisononyl adipate (a sika reagent) to the prepolymer obtained in the step (1), stirring and mixing at a rotation speed of 600rpm for about 1min by using a mechanical stirrer (german IKA, RW 20), adding 131.9 parts by mass of 1, 4-butanediol previously adjusted to 80 ℃ to the system, and sufficiently stirring for about 2min until the mixture is uniform to obtain a mixed solution;

(3) The mixed solution obtained in step (2) was poured into a pan made of stainless steel, which had been previously adjusted to a temperature of 150 ℃, and reacted at 150 ℃ for 1 hour and then at 100 ℃ for 23 hours to obtain an elastomer.

(4) And (4) taking the elastomer obtained in the step (3) off the disc, and curing for 7 days under the conditions of the room temperature of 23 ℃ and the constant temperature and humidity of 55% of relative humidity to obtain the polyurethane elastomer.

Evaluation of properties of polyurethane elastomer:

performing injection molding on a polyurethane elastomer (raw material, mixed liquid obtained in the step (2) in an application example) to be tested by using an injection molding machine (model: NEX-140, taifu machine) under the conditions of a screw rotating speed of 100rpm and a charging barrel temperature of 150-235 ℃, a mold temperature of 20 ℃, an injection time of 10s, an injection speed of 60mm/s and a cooling time of 45s to obtain a sheet;

the obtained sheet (thickness: 2 mm) was cured for 7 days under constant temperature and humidity conditions at 23 ℃ and a relative humidity of 55%, to obtain a polyurethane elastomer sheet for testing, and specifically subjected to the following performance tests:

(1) Firstly, measuring the b value (b 1, initial value) of the polyurethane elastomer sheet by using a chromometer; then, a xenon lamp irradiation test is carried out, the polyurethane elastomer sheet is placed in a super xenon lamp climate test box (Weibang instrument), and the xenon lamp irradiance is 100W/m at the temperature of 89 ℃, the relative humidity of 50 percent ² (irradiation wavelength 300-400 nm) for 240 hours, and then the sheet was taken out and tested for the b value (b 2) by the same method as described above. Calculating the color difference delta b, delta b = |, b2-b1 |, of the polyurethane elastomer after 240h of a damp-heat aging test under the irradiation of a xenon lamp;

(2) Tensile strength: the tensile strength of the elastomer was tested according to the method in GB/T528-2009;

(3) Tear strength: the tear strength of the elastomers was tested according to the method in GB/T529-2008;

the results of the foregoing tests are shown in tables 4, 5 and 6.

TABLE 4

TABLE 5

TABLE 6

According to the combination of the above performance test data, the polyurethane elastomer prepared based on the isocyanate composition has excellent stability and weather resistance by controlling the effective factor of the isocyanate composition within the range of 3.80-5.30, the color difference delta b after the xenon lamp irradiation and the damp-heat aging treatment for 240 hours is less than 3.0 and as low as 2.53-2.95, the color number growth and yellowing under the damp-heat condition are inhibited, and the tensile strength and the tear strength of the polyurethane elastomer are improved, wherein the tensile strength of the polyurethane elastomer prepared from the NDI composition is 41.3-42.5MPa, and the tear strength is 64.1-65.2kN/m; the tensile strength of the polyurethane elastomer prepared by the PPDI composition is 44.3-45.7MPa, and the tearing strength is 119.6-121.6kN/m; the tensile strength of the polyurethane elastomer prepared by the CHDI composition is 35.1-36.1MPa, and the tearing strength is 59.0-60.1kN/m, so that the polyurethane elastomer keeps comprehensive product performances such as excellent appearance, weather resistance, mechanical properties and the like. Therefore, the isocyanate composition provided by the invention has better application prospect in polyurethane elastomers.

The Applicant states that the present invention is illustrated by the above examples of isocyanate compositions, modified compositions and polyurethane elastomers, but the invention is not limited to the above process steps, i.e. it is not meant that the invention must rely on the above process steps to be carried out. 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 3.80 to 5.30;

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 naphthalene diisocyanate, benzene diisocyanate, cyclohexane diisocyanate, toluene diisocyanate, diphenylmethane 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 chlorinated isocyanate is a compound obtained by substituting one NCO group in an isocyanate by chlorine;

preferably, the chlorinated isocyanate comprises

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

4. The isocyanate composition according to any one of claims 1 to 3, 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.

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

the modifying composition comprises any one of 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, characterized in that the isocyanate-based polymer is obtained by reacting an isocyanate-based substance with an active hydrogen group-containing substance; the isocyanate-based material comprises at least one of the isocyanate composition of any one of claims 1 to 5 and the modified composition of claim 8.

10. The polyurethane elastomer is characterized in that the preparation raw materials of the polyurethane elastomer comprise isocyanate substances and polyol; the isocyanate-based material comprises the isocyanate composition of any one of claims 1 to 5 and/or the modified composition of claim 8;

preferably, the preparation raw material further comprises a chain extender;

preferably, the chain extender comprises a low molecular weight polyol and/or a low molecular weight polyamine.

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