A polyisocyanate composition, a method for producing the same, and use thereof

Abstract

The present application relates to a polyisocyanate composition, a preparation method and application thereof, the composition comprising derivatives of a plurality of diisocyanates, the derivatives of the diisocyanates being obtained by substituting at least one isocyanate group in the diisocyanate with at least one substituent group, the at least one substituent group comprising one or more of isocyanurate groups, substituted biuret groups and substituted urea groups; the molar ratio of the substituted biuret groups to the substituted urea groups contained in the polyisocyanate composition being greater than 0 and less than or equal to 0.5; the viscosity of the polyisocyanate composition being 10000 mPa.s or less; and the diisocyanate comprising one or more of aliphatic diisocyanates and alicyclic diisocyanates. The polyisocyanate composition according to an embodiment of the present application has the characteristics of low viscosity and good storage stability.

Description

Technical Field

[0001] This invention relates to polyisocyanate compositions, and more particularly to a polyisocyanate composition with good storage stability. Background Technology

[0002] Aliphatic / alicyclic polyisocyanates have excellent properties such as weather resistance, wear resistance, and corrosion resistance, and are widely used in the coatings, adhesives, and elastomers industries. In particular, in the coatings industry, polyisocyanate curing agents containing isocyanate groups are the most widely used.

[0003] Aliphatic polyisocyanate compositions containing isocyanurate groups have excellent resistance to yellowing. In addition, they also have advantages such as low free monomer content, saturated vapor concentration far below occupational safety limits, high functionality, and high downstream crosslinking density.

[0004] Given the diversity of downstream application formulations, curing agents often need to be used in conjunction with high-hydroxy resins to improve the crosslinking density, mechanical properties, and chemical resistance of the coating film. However, due to the rigid structure of the isocyanurate ring itself, the polyisocyanates prepared from it often have high viscosity. In downstream applications, a large amount of solvent needs to be added to reduce the viscosity, which can lead to thinning, cloudiness, and bluish tint in the composition, affecting the gloss of the formed coating film.

[0005] Existing technologies mainly reduce the viscosity of polyisocyanates by modifying them with polyols and introducing other structures. However, polyol modification can result in a lower -NCO content in the prepared polyisocyanates. The structure of diurea ketone can reduce the hardness and chemical resistance of the coating film prepared by polyisocyanates compared to that of isocyanurates. Summary of the Invention

[0006] To overcome at least one of the defects of the prior art, in a first aspect, one embodiment of the present invention provides a polyisocyanate composition comprising a plurality of diisocyanate derivatives, wherein the diisocyanate derivatives are obtained by substituting at least one isocyanate group in the diisocyanate with at least one substituent group, wherein the at least one substituent group comprises one or more of isocyanurate groups, substituted biuret groups, and substituted urea groups; the molar ratio of substituted biuret groups to substituted urea groups in the polyisocyanate composition is greater than 0 and less than or equal to 0.5; the viscosity of the polyisocyanate composition is less than 10000 mPa·s; the diisocyanate comprises one or more of aliphatic diisocyanates and alicyclic diisocyanates; the viscosity is measured by a viscometer at 23°C;

[0007] The structures of the substituted biuret group and the substituted urea group are as follows:

[0008]

[0009] R1 and R2 are each independently selected from C1 to C2. 12 Alkyl groups that are straight-chain or branched.

[0010] Secondly, one embodiment of the present invention provides a method for preparing the above-mentioned polyisocyanate composition, comprising reacting the diisocyanate with a fatty amine to obtain the polyisocyanate composition.

[0011] Thirdly, one embodiment of the present invention provides the application of the above-described polyisocyanate composition or the polyisocyanate composition prepared by the above-described preparation method as a crosslinking agent or curing agent.

[0012] The polyisocyanate composition of one embodiment of the present invention has the characteristics of low viscosity and good storage stability. Detailed Implementation

[0013] Typical embodiments embodying the features and advantages of the present invention will be described in detail in the following description. It should be understood that the present invention can have various variations in different embodiments without departing from the scope of the present invention, and the description herein is for illustrative purposes only and not intended to limit the present invention.

[0014] One embodiment of the present invention provides a polyisocyanate composition comprising a variety of diisocyanate derivatives, wherein the diisocyanate derivatives are obtained by substituting at least one (e.g., one or two) isocyanate groups in the diisocyanate with at least one substituent group, wherein the at least one substituent group includes one or more of isocyanurate groups, substituted biuret groups, and substituted urea groups; the molar ratio of substituted biuret groups to substituted urea groups in the polyisocyanate composition (or the various diisocyanate derivatives) is greater than 0 and less than or equal to 0.5; the viscosity of the polyisocyanate composition is less than 10000 mPa·s; the diisocyanate includes one or more of aliphatic diisocyanates and alicyclic diisocyanates; the above viscosity is measured by a viscometer at 23°C;

[0015] The structures of the substituted biuret group and the substituted urea group are as follows:

[0016]

[0017] R1 and R2 are each independently selected from C1 to C2. 12 Alkyl groups that are straight-chain or branched.

[0018] In one embodiment, the viscosity of the polyisocyanate composition is below 10,000 mPa·s, and more preferably between 900 and 10,000 mPa·s, such as 920 mPa·s, 930 mPa·s, 1,000 mPa·s, 2,000 mPa·s, 3,000 mPa·s, 40,000 mPa·s, 5,000 mPa·s, 5,330 mPa·s, 5,340 mPa·s, and 5,500 mPa·s. Viscosities of 6000 mPa·s, 7000 mPa·s, 7460 mPa·s, 7470 mPa·s, 7500 mPa·s, 8000 mPa·s, 8500 mPa·s, 8900 mPa·s, 8940 mPa·s, 8950 mPa·s, 9000 mPa·s, 9500 mPa·s, 9710 mPa·s, 9720 mPa·s, and 9800 mPa·s were measured at 23°C using a viscometer (e.g., a Brookfield DV-IPrime viscometer).

[0019] In one embodiment, the molar ratio of substituted biuret groups to substituted urea groups in the polyisocyanate composition (or derivatives of various diisocyanates) can be (0.05 to 0.50):1, more preferably (0.10 to 0.45):1, for example 0.11:1, 0.15:1, 0.2:1, 0.25:1, 0.28:1, 0.3:1, 0.35:1, 0.38:1, 0.4:1, 0.44:1.

[0020] In one embodiment, the number of carbon atoms contained in R1 and R2 of the substituted biuret group and the substituted urea group can be 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 or 12.

[0021] In one embodiment, R1 and R2 may be the same or different; further, R1 and R2 are each independently selected from ethyl, propyl, n-butyl, isobutyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, isooctyl, and n-nonyl.

[0022] In one embodiment, some diisocyanate derivatives include substituent groups, while others include isocyanate groups and substituent groups. Further, the isocyanate group content in the polyisocyanate composition can be 18–26 wt%, for example 19 wt%, 20 wt%, 21 wt%, 22 wt%, 23 wt%, 24 wt%, or 25 wt%, based on the total mass of the polyisocyanate composition.

[0023] In one embodiment, the polyisocyanate composition includes less than 0.5 wt% of diisocyanate, for example, the content of diisocyanate in the polyisocyanate composition may be 0.05 wt%, 0.07 wt%, 0.08 wt%, 0.1 wt%, 0.15 wt%, 0.16 wt%, 0.18 wt%, 0.2 wt%, 0.24 wt%, 0.25 wt%, 0.3 wt%, or 0.4 wt%.

[0024] In one embodiment, the substituted isocyanurate group in the diisocyanate derivative is obtained by self-polymerization of three isocyanate groups.

[0025] In one embodiment, the substituent groups contained in the polyisocyanate composition include isocyanurate groups, substituted biuret groups, and substituted urea groups. Further, the sum of the mass contents of the substituted biuret groups and substituted urea groups is ≤10%, and the mass content of the isocyanurate groups can be greater than or equal to 90% and less than 100%, with the aforementioned mass contents based on the total mass of the substituent groups (i.e., the sum of the mass contents of the substituted biuret groups, substituted urea groups, and isocyanurate groups).

[0026] In one embodiment, the polyisocyanate composition is obtained by reacting a diisocyanate with a fatty amine.

[0027] In one embodiment, the diisocyanate has the structural formula OCN-R-NCO, where R is an alkylene group containing 5 to 10 (e.g., 6, 7, 8, 9, 10) carbon atoms, including open-chain alkylene groups (e.g., -CH2-CH2-CH2-CH2-CH2-) and cycloalkylene groups (e.g., cyclohexylene-C6H). 10 -), and open-chain alkylene groups including cycloalkyl substituents.

[0028] In one embodiment, the diisocyanate includes one or more of hexamethylene diisocyanate (HDI), pentamethylene diisocyanate (PDI), 2-methylpentane-1,5-diisocyanate, 2,2,4-trimethyl-1,6-hexane diisocyanate, isophorone diisocyanate, 1,3-bis(isocyanate methyl)cyclohexane, and 1,4-bis(isocyanate methyl)cyclohexane.

[0029] In one embodiment, the fatty amine may be a primary amine and / or a secondary amine, and more particularly, a secondary amine.

[0030] In one embodiment, the fatty amine comprises 2 to 24 carbon atoms; further, the fatty amine comprises 4 to 20 carbon atoms, for example, the number of carbon atoms contained in the fatty amine can be 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, or 23.

[0031] In one embodiment, the fatty amine has the structural formula R1-NH-R2, where R1 and R2 are subject to the foregoing limitations.

[0032] In one embodiment, the fatty amine includes one or more of diethylamine, dipropylamine, di-n-butylamine, diisobutylamine, di-n-pentylamine, diisopentylamine, di-n-hexylamine, di-n-heptylamine, di-n-octylamine, diisooctylamine, and di-n-nonylamine.

[0033] One embodiment of the present invention provides a method for preparing the above-mentioned polyisocyanate composition, comprising reacting the above-mentioned diisocyanate and the above-mentioned fatty amine to prepare the polyisocyanate composition.

[0034] In one embodiment, the specific amounts of diisocyanate and fatty amine are determined such that the molar ratio of substituted biuret groups to substituted urea groups in the resulting polyisocyanate composition meets the above-mentioned limitations. Further, the molar ratio of the amino (or nitrogen) atom contained in the fatty amine to the isocyanate group contained in the diisocyanate can be greater than 0 and less than or equal to 0.06, for example, 0.01, 0.02, 0.03, 0.04, or 0.05.

[0035] In one embodiment, the reaction temperature of the diisocyanate and the fatty amine can be 10-150°C, further 30-79°C, and even further 45-75°C, for example 20°C, 35°C, 40°C, 50°C, 55°C, 60°C, 65°C, 70°C, 75°C, 90°C, 100°C, and 120°C.

[0036] In one embodiment, the reaction between the diisocyanate and the fatty amine is carried out in the presence of a catalyst, which may be one or more of the following: quaternary ammonium hydroxide, quaternary ammonium carboxylate, aminomethylsilyl compound, tertiary amine compound, Mannich base compound, and metal salt compound.

[0037] In one embodiment, the quaternary ammonium hydroxide may be one or more of tetramethylammonium hydroxide, trimethylbenzylammonium hydroxide, tetraethylammonium hydroxide, dimethylethylcyclohexylammonium hydroxide and their hydrates, preferably one or more of tetramethylammonium hydroxide and trimethylbenzylammonium hydroxide and their hydrates.

[0038] In one embodiment, the quaternary ammonium carboxylate can be one or more of tetramethylammonium hydroxide-2-ethylhexanoate, tetramethylammonium hydroxide-octanoate, trimethylbenzylammonium hydroxide-2-ethylhexanoate, trimethylbenzylammonium hydroxide-octanoate, tetramethylammonium hydroxide-formate, tetramethylammonium hydroxide-acetate, tetramethylammonium hydroxide-pentanoate, trimethylbenzylammonium hydroxide-pentanoate, tetramethylammonium hydroxide-decanoate, trimethylbenzylammonium hydroxide-decanoate, tetramethylammonium hydroxide-tetradecanoate, tetramethylammonium hydroxide-2-ethylhexanoate, tetramethylammonium hydroxide-octanoate, trimethylbenzylammonium hydroxide-2-ethylhexanoate, and trimethylbenzylammonium hydroxide-octanoate.

[0039] In one embodiment, the compound containing aminosilyl groups may be one or more of hexamethyldisilazane, silylamine, and heptamethyldisilazane, preferably hexamethyldisilazane.

[0040] In one embodiment, the tertiary amine compound may be one or both of triethylamine and tripropylamine, preferably triethylamine.

[0041] In one embodiment, the Mannich base compound may be 2,4,6-tris(dimethylaminomethyl)phenol.

[0042] In one embodiment, the metal salt compound may be tin isooctanoate.

[0043] In one embodiment, the catalyst can be used as a pure substance or dissolved in a solvent at any concentration.

[0044] In one embodiment, the mass of the catalyst is 0.001 to 0.1% of the mass of the diisocyanate used as a raw material, more specifically 0.005 to 0.05%, for example 0.001%, 0.005%, 0.01%, 0.02 wt%, 0.03 wt%, 0.04 wt%, 0.06 wt%, or 0.08 wt%.

[0045] In one embodiment, the reaction endpoint of diisocyanate and fatty amine is defined as an NCO% value (or mass content of isocyanate groups) of 30-50% in the reaction system, for example, 30%, 35%, 37%, 40%, 43%, 45%, 47%, and 50%. When the NCO% value of the reaction system is greater than 50%, it often leads to problems such as low conversion rate, high monomer consumption, increased energy consumption required for subsequent diisocyanate removal process, and low functionality of the composition. When the NCO% value is less than 30%, the viscosity of the polyisocyanate composition is too high, which will adversely affect the convenience of downstream construction and the leveling properties of the paint film.

[0046] The NCO% in this article was determined according to the method of GB / T 12009.4-2016, where NCO% refers to the mass percentage of isocyanate groups (-NCO).

[0047] In one embodiment, the polymerization reaction is terminated when the reaction system reaches the target NCO% threshold. The reaction can be terminated by adding a catalyst poison to the reaction system. Further, the catalyst poison can be one or more of an acidic reactive substance (e.g., a protic acid) and an acylating agent (e.g., isophthalic acid dichloroisocyanurate, benzenesulfonyl chloride).

[0048] In one embodiment, the catalyst poison is selected from one or more of protic acids and acylating agents, such as phosphoric acid, benzoic acid, diisooctyl phosphate, dibutyl phosphate, and p-toluenesulfonic acid.

[0049] In one embodiment, the amount of catalyst poison added is determined by the amount that deactivates the catalyst in the system.

[0050] In one embodiment, the mixture after the reaction of diisocyanate and fatty amine can be evaporated to remove unreacted diisocyanate, keeping the residual monomer content in the polyisocyanate composition below 0.5 wt%. Further, a single-stage or multi-stage thin-film evaporator can be used to treat the mixture after the reaction of diisocyanate and fatty amine.

[0051] One embodiment of the present invention provides the application of the above-described polyisocyanate composition as a crosslinking agent or curing agent, particularly as a crosslinking agent or curing agent in coating compositions.

[0052] One embodiment of the present invention provides a polyisocyanate composition that, by introducing a specific amount of substituted biuret groups and substituted urea groups into a polyisocyanate containing isocyanurate groups, can significantly reduce the viscosity of the polyisocyanate composition while maintaining good storage stability.

[0053] The preparation of a polyisocyanate composition according to one embodiment of the present invention will be further described below with reference to examples. The raw materials and testing methods involved in each example and comparative example are as follows.

[0054] raw material

[0055] 1. PDI: Pentamethylene diisocyanate, Wanhua Chemical Group Co., Ltd.;

[0056] 2. Di-n-butylamine: Aladdin Reagent Company;

[0057] 3. Di-n-Octylamine: Aladdin Reagent Company;

[0058] 4. Tetramethylammonium hydroxide-2-ethylhexanoate: Kent Chemicals Ltd.;

[0059] 5. Hexamethyldisilazane: Inokai Technology Co., Ltd.

[0060] 6. Tetramethylammonium hydroxide pentahydrate: Inokai Technology Co., Ltd.;

[0061] 7. Tetraethylammonium hydroxide: Inokai Technology Co., Ltd.

[0062] 8. Acetone: Inocare Technology Co., Ltd.

[0063] Test methods

[0064] 1. NCO content

[0065] The -NCO content was determined according to the method in GB / T 12009.4-2016.

[0066] 2. Residual diisocyanate content

[0067] The content of residual diisocyanate in the reaction system was determined by gas chromatography according to the method of GB / T18583-2008.

[0068] 3. Viscosity

[0069] Viscosity was measured at 23°C using a BrookField DV-IPrime viscometer with an S21 rotor.

[0070] 4. Content of substituted biuret groups and substituted urea groups

[0071] The content (% molar) and molar ratio (equivalent ratio) of substituted biuret groups and substituted urea groups in the polyisocyanate composition are used. 1 The results were obtained using H-NMR spectroscopy. The specific testing conditions are as follows:

[0072] 1 H-NMR equipment: AVANCE600 (Bruker), equipped with BBO probe (Bruker); sample concentration: 5wt%; resonance frequency: 600MHz; shift reference: 0ppm (TMS); pulse program: zg30; spectral width: 24ppm; spectral center: 6ppm.

[0073] The molar ratio of substituted urea groups and substituted biuret groups was calculated by the ratio of the integral value near 5.7 ppm to the integral value near 6.0 ppm.

[0074] Example 1

[0075] Add 850g of PDI to the reactor, stir and heat to 50℃ under a nitrogen atmosphere, then add 12.5g of di-n-butylamine to the reactor and maintain the temperature at 50℃; add 0.64g of tetraethylammonium hydroxide solution (20wt%, acetone solution) dropwise to the system, and monitor the NCO% of the reaction solution. When the NCO% value drops to 38.7%, add 0.09g of p-toluenesulfonic acid to the system to terminate the reaction.

[0076] The reaction solution was separated using a short-path evaporator (separation temperature 150℃, pressure 12Pa) to remove unreacted PDI monomers, yielding polyisocyanate composition 1.

[0077] Example 2

[0078] Add 850g of PDI to the reactor, stir and heat to 55℃ under a nitrogen atmosphere, then add 18.7g of di-n-butylamine to the reactor and maintain the temperature at 55℃; add 1.02g of tetramethylammonium hydroxide-2-ethylhexanoate solution (20wt%, n-butanol solution) dropwise to the system, and monitor the NCO% of the reaction solution. When the NCO% value drops to 38.5%, add 0.14g of dibutyl phosphate to the system to terminate the reaction.

[0079] The reaction solution was separated using a short-path evaporator (separation temperature 160℃, pressure 12Pa) to remove unreacted PDI monomers, yielding polyisocyanate composition 2.

[0080] Example 3

[0081] Add 850g of PDI to the reactor, stir and heat to 120℃ under nitrogen atmosphere, then add 10g of di-n-octylamine to the reactor and maintain 120℃; add 0.8g of hexamethyldisilazane dropwise to the system, and monitor the NCO% of the reaction solution. When the NCO% value drops to 39.0%, add 1g of n-butanol to the system to terminate the reaction.

[0082] The reaction solution was separated using a short-path evaporator (separation temperature 150℃, pressure 12Pa) to remove unreacted PDI monomers, yielding polyisocyanate composition 3.

[0083] Example 4

[0084] Add 850g of PDI to the reactor, stir and heat to 90℃ under a nitrogen atmosphere, then add 14.4g of di-n-propylamine to the reactor and maintain the temperature at 90℃; add 0.43g of tetramethylammonium hydroxide pentahydrate solution (20wt%, acetone solution) dropwise to the system, and monitor the NCO% of the reaction solution. When the NCO% value drops to 48.3%, add 0.03g of phosphoric acid to the system to terminate the reaction.

[0085] The reaction solution was separated using a short-path evaporator (separation temperature 155℃, pressure 10Pa) to remove unreacted PDI monomers, yielding polyisocyanate composition 4.

[0086] Example 5

[0087] Add 850g of PDI to the reactor, stir and heat to 55℃ under nitrogen atmosphere, then add 30g of diisopropylamine to the reactor and maintain 55℃; add 0.77g of tin isooctanoate solution (20wt%, n-butanol solution) dropwise to the system, and monitor the NCO% of the reaction solution. When the NCO% value drops to 36.4%, add 0.10g of benzenesulfonyl chloride to the system to terminate the reaction.

[0088] The reaction solution was separated using a short-path evaporator (separation temperature 155℃, pressure 10Pa) to remove unreacted PDI monomers, yielding polyisocyanate composition 5.

[0089] Comparative Example 1

[0090] Add 850g of PDI to the reactor, stir and heat to 55℃ under nitrogen atmosphere, then add 1.02g of tetramethylammonium hydroxide-2-ethylhexanoate solution (20wt%, n-butanol solution) dropwise to the system. Monitor the NCO% of the reaction solution. When the NCO% value drops to 38.5%, add 0.14g of dibutyl phosphate to the system to terminate the reaction.

[0091] The reaction solution was separated using a short-path evaporator (separation temperature 160℃, pressure 12Pa) to remove unreacted PDI monomers, yielding polyisocyanate composition A.

[0092] Comparative Example 2

[0093] Add 850g of PDI to the reactor, stir and heat to 100℃ under a nitrogen atmosphere, then add 18.7g of di-n-butylamine to the reactor, and while maintaining the temperature at 100℃, add 1.02g of tetramethylammonium hydroxide-2-ethylhexanoate solution (20wt%, n-butanol solution) dropwise to the system. Monitor the NCO% of the reaction solution. When the NCO% value drops to 36.5%, add 0.14g of dibutyl phosphate to the system to terminate the reaction.

[0094] The reaction solution was separated using a short-path evaporator (separation temperature 160℃, pressure 12Pa) to remove unreacted PDI monomers, yielding polyisocyanate composition B.

[0095] Comparative Example 3

[0096] Add 850g of PDI to the reactor, stir and heat to 40°C under a nitrogen atmosphere, then add 0.42g of tris(dimethylamino)phosphine to the reactor. After reacting for 1 hour, add 4.9wt% of terpentine based on PDI, heat to 110°C, slowly add 7.2g of water, and stir to react for 2 hours.

[0097] The reaction solution was separated using a short-path evaporator (separation temperature 160℃, pressure 12Pa) to remove unreacted PDI monomers, yielding polyisocyanate composition C.

[0098] The polyisocyanate compositions prepared in Examples 1-5 and Comparative Examples 1-3 were subjected to relevant tests according to the aforementioned method, and the results are shown in Table 1.

[0099] Table 1 Performance results of the polyisocyanate compositions of each example and comparative example.

[0100]

[0101]

[0102] According to the results in Table 1, the molar ratio of substituted biuret groups to substituted urea groups in the polyisocyanate compositions of Examples 1-5 is all between 0 and 0.5, while the corresponding molar ratios for Comparative Examples 1 and 3 are 0, and the corresponding molar ratio for Comparative Example 2 is 0.55, which is greater than 0.5. Based on the viscosity values ​​of the polyisocyanate compositions, the viscosity of the polyisocyanate compositions of Examples 1-5 is lower than that of Comparative Examples 1-3. Therefore, by limiting the molar ratio of substituted biuret groups to substituted urea groups in the polyisocyanate compositions to between 0 and 0.5, their viscosity can be significantly reduced.

[0103] The viscosity changes and diisocyanate content of the polyisocyanate compositions of Examples 1-5 and Comparative Examples 1-3 were tested after being stored at 50°C for 3 months. The results are shown in Table 2.

[0104] Table 2 Viscosity indices of the polyisocyanate compositions in each example and comparative example

[0105]

[0106] As shown in Table 2, after 3 months of storage, the viscosity of the polyisocyanate compositions in Examples 1-5 showed little change, and the content of free diisocyanate was low, indicating good storage stability. Furthermore, the composition in Comparative Example 3 contained a certain amount of urea diketone, which decomposed into diisocyanate during heating and storage, resulting in a diisocyanate content >0.5%.

[0107] Unless otherwise specified, the terms used in this invention have the meanings commonly understood by those skilled in the art.

[0108] The embodiments described in this invention are for illustrative purposes only and are not intended to limit the scope of protection of this invention. Those skilled in the art can make various other substitutions, changes and improvements within the scope of this invention. Therefore, this invention is not limited to the above embodiments, but is only defined by the claims.

Claims

1. A polyisocyanate composition comprising a plurality of derivatives of diisocyanates, the derivatives of diisocyanates being obtained by substituting at least one isocyanate group in the diisocyanates with at least one substituent group comprising one or more of isocyanurate group, substituted biuret group, and substituted urea group; a molar ratio of the substituted biuret group to the substituted urea group contained in the polyisocyanate composition being greater than 0 and less than or equal to 0.5; a viscosity of the polyisocyanate composition being 10,000 mPa.s or less; the diisocyanates comprising one or more of aliphatic diisocyanates and alicyclic diisocyanates; the viscosity being measured by a viscometer at 23°C; the polyisocyanate composition comprising 0.5 wt% or less of the diisocyanates; the polyisocyanate composition being obtained by reacting the diisocyanates and a fatty amine having a formula of R1-NH-R2; the diisocyanates having a formula of OCN-R-NCO, wherein R is an alkylene group having 5 to 10 carbon atoms, the alkylene group comprising open chain alkylene group, cyclic alkylene group, and open chain alkylene group including cyclic alkyl substituent; the polyisocyanate composition comprising 18 to 26 wt% of isocyanate groups; wherein the substituted biuret group and the substituted urea group having the following structures: R1 and R2 may be the same or different, and each is independently selected from C1 to C2. 12 Alkyl groups that are straight-chain or branched.

2. The composition of claim 1, wherein, a molar ratio of the substituted biuret group to the substituted urea group contained in the polyisocyanate composition being (0.05 to 0.50): 1; and / or, a viscosity of the polyisocyanate composition being 900 to 10,000 mPa.s; and / or, R1 and R2 are each independently selected from one or more of C1 to C8 straight chain or branched alkyl groups.

3. The composition of claim 1, wherein, R1 and R2 are each independently selected from one or more of ethyl group, propyl group, n-butyl group, iso-butyl group, n-pentyl group, n-hexyl group, n-heptyl group, n-octyl group, iso-octyl group, and n-nonyl group; and / or, the substituent groups contained in the polyisocyanate composition comprising the isocyanurate group, the substituted biuret group, and the substituted urea group, a total mass content of the substituted biuret group and the substituted urea group being less than or equal to 10% based on a total mass of the substituent groups.

4. The composition of claim 1, wherein, a molar ratio of the substituted biuret group to the substituted urea group contained in the polyisocyanate composition being (0.10 to 0.45): 1; and / or, the diisocyanates comprising one or more of hexamethylene diisocyanate, pentamethylene diisocyanate, 2-methylpentane-1,5-diisocyanate, 2,4,4-trimethyl-1,6-hexane diisocyanate, 2,2,4-trimethyl-1,6-hexane diisocyanate, isophorone diisocyanate, 1,3-bis(isocyanatomethyl)cyclohexane, and 1,4-bis(isocyanatomethyl)cyclohexane.

5. A method of producing the polyisocyanate composition according to any one of claims 1 to 4, comprising reacting the diisocyanates and a fatty amine to produce the polyisocyanate composition.

6. The production method according to claim 5, wherein The molar ratio of the amino group contained in the fatty amine to the isocyanate group contained in the diisocyanate is greater than 0 and less than or equal to 0.06; and / or, The reaction endpoint of the reaction is that the isocyanate group content of the reaction system is 30-50wt%.

7. The production method according to claim 5, wherein The temperature of the reaction is 10-150℃; and / or, The reaction is carried out in the presence of a catalyst, and the catalyst includes one or more of quaternary ammonium hydroxides, quaternary ammonium carboxylates, aminosilyl-containing compounds, tertiary amine compounds, Mannich base compounds, and metal salt compounds.

8. The production method according to claim 7, wherein The fatty amine includes 4-20 carbon atoms; and / or, The temperature of the reaction is 30-79℃; and / or, The mass of the catalyst is 0.001-0.1% of the mass of the diisocyanate.

9. The production method according to claim 7, wherein The fatty amine includes one or more of diethylamine, dipropylamine, di-n-butylamine, diisobutylamine, di-n-amylamine, diisopentylamine, di-n-hexylamine, di-n-heptylamine, di-n-octylamine, diisooctylamine, and di-n-nonylamine; and / or, The temperature of the reaction is 45-75℃; and / or, The mass of the catalyst is 0.005-0.05% of the mass of the diisocyanate.

10. Use of the polyisocyanate composition of any one of claims 1-4 or the polyisocyanate composition prepared by the preparation method of any one of claims 5-9 as a crosslinking agent or a curing agent.

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