A polyisocyanate composition, process for its preparation and use thereof

Abstract

The present application relates to a polyisocyanate composition, a preparation method and application thereof, the polyisocyanate composition comprising an aliphatic diisocyanate modifier, an aliphatic-aromatic diisocyanate modifier and optionally an aromatic diisocyanate modifier; the aliphatic diisocyanate modifier is obtained by reaction of aliphatic diisocyanate; the aromatic diisocyanate modifier is obtained by reaction of aromatic diisocyanate; the aliphatic-aromatic diisocyanate modifier is obtained by reaction of aliphatic diisocyanate and aromatic diisocyanate; the aliphatic diisocyanate is aliphatic diisocyanate and / or alicyclic diisocyanate; the mass of isocyanurate groups contained in the aliphatic diisocyanate modifier is >0 and ≤10% based on the total mass of isocyanurate groups in the polyisocyanate composition. The polyisocyanate composition is used in polyurethane coatings, which can improve the yellowing resistance, pendulum hardness and dryability of the coating.

Description

Technical Field

[0001] This invention belongs to the technical field of polyisocyanate compositions, specifically relating to a polyisocyanate composition, its preparation method, and its application. Background Technology

[0002] Polyisocyanate curing agents are widely used in paint raw materials, as well as in polyurethane elastomers and polyurethane foams. Among them, aliphatic polyisocyanate curing agents containing isocyanurate groups have excellent resistance to yellowing, but their products have a slower drying rate and poorer hardness and abrasion resistance. Aromatic polyisocyanate curing agents containing isocyanurate groups have a faster drying rate, higher hardness, and excellent abrasion resistance, but the presence of aromatic rings makes their products less resistant to yellowing.

[0003] Polyisocyanate compositions obtained by blending aliphatic / aliphatic diisocyanates and aromatic diisocyanates can combine the advantages of both to a certain extent, resulting in polyisocyanate compositions with superior resistance to yellowing, abrasion resistance, and drying rate. Existing technologies include directly mixing aliphatic diisocyanate compositions containing isocyanurate groups with aromatic polyisocyanate compositions containing isocyanurate groups to obtain polyisocyanate compositions; however, these polyisocyanate compositions, when used as curing agents, exhibit uneven drying rates due to differences in reaction rates. Another approach involves mixing aliphatic / aliphatic diisocyanate monomers with aromatic diisocyanate monomers and then adding a catalyst to obtain polyisocyanate compositions.

[0004] CN103242254B obtained an HDI-TDI polyurethane trimer by blending TDI and HDI. Compared with the TDI trimer, it has better resistance to yellowing and adhesion, and compared with the HDI trimer, it has faster drying speed. US4518761 provides a method for preparing a curing agent by blending aliphatic diisocyanate monomers and aromatic diisocyanate monomers. However, aromatic diisocyanate monomers have high reactivity. If aliphatic diisocyanate monomers are directly mixed with aromatic diisocyanate monomers, the aromatic diisocyanate monomers will react preferentially, resulting in the inability to separate them. US5798431 first adds a catalyst to initiate the trimerization reaction of aliphatic diisocyanate, and then adds aromatic diisocyanate dropwise to the reaction system to solve the above problem. However, initiating the reaction with aliphatic diisocyanate first results in a high content of aliphatic diisocyanate-based trimer in the system, thus affecting the drying speed.

[0005] Therefore, there is a need to develop a polyisocyanate composition for use as a crosslinking agent in two-component polyurethane coating compositions, which can give the coating good resistance to yellowing, good pendulum hardness and drying properties. Summary of the Invention

[0006] To address the shortcomings of existing technologies, the present invention aims to provide a polyisocyanate composition, its preparation method, and its application. The polyisocyanate composition provided by the present invention can be used as a crosslinking agent for two-component polyurethane coating compositions, and can give the coating good resistance to yellowing, good pendulum hardness, and good drying properties.

[0007] To achieve this objective, the present invention adopts the following technical solution:

[0008] In a first aspect, the present invention provides a polyisocyanate composition comprising an aliphatic diisocyanate modifier, an aliphatic-aromatic diisocyanate modifier, and optionally an aromatic diisocyanate modifier; wherein the aliphatic diisocyanate modifier is obtained by reacting an aliphatic diisocyanate; the aromatic diisocyanate modifier is obtained by reacting an aromatic diisocyanate; the aliphatic-aromatic diisocyanate modifier is obtained by reacting an aliphatic diisocyanate with an aromatic diisocyanate; wherein the aliphatic diisocyanate is an aliphatic diisocyanate and / or an alicyclic diisocyanate; and wherein, based on the total mass of isocyanurate groups in the polyisocyanate composition being 100%, the mass of isocyanurate groups contained in the aliphatic diisocyanate modifier is >0 and ≤10%.

[0009] The polyisocyanate composition provided by this invention is derived from aliphatic diisocyanates and aromatic diisocyanates. By controlling the mass percentage of isocyanurate groups contained in the aliphatic diisocyanate modifier within the range of >0 and ≤10% relative to the total mass of isocyanurate groups in the polyisocyanate composition, it is beneficial to improve the yellowing resistance of the polyurethane coating composition and can also take into account good drying properties and pendulum hardness.

[0010] The aliphatic diisocyanate modifier contains isocyanurate groups with a mass >0 and ≤10%, for example, it can be 0.1%, 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, 5.5%, 6%, 6.5%, 7%, 7.5%, 8%, 8.5%, 9%, 9.5%, etc.

[0011] In this invention, the structure of the isocyanurate group is as follows: in The linking site of the representative group.

[0012] In this invention, the aliphatic diisocyanate modifier comprises at least one of the following compounds:

[0013]

[0014] R1 is independently selected from any one of C1-C20 straight-chain or branched alkylene groups and C3-C30 cycloalkylene groups; n is selected from integers ≥0; R1 can be the same or different.

[0015] In this invention, the aromatic diisocyanate modifier comprises at least one of the following compounds:

[0016]

[0017] In this context, R2 is independently selected from any one of C6-C30 arylene groups; m is selected from integers ≥0; R2 can be the same or different.

[0018] In this invention, the aliphatic-aromatic diisocyanate modifier comprises at least one of the following compounds:

[0019]

[0020] Wherein, each of R3 is independently selected from any one of C6-C30 arylene, C1-C20 straight-chain or branched alkylene, and C3-C30 cycloalkylene; p is selected from an integer ≥0; and at least one R3 is selected from any one of C6-C30 arylene, and at least one R3 is selected from any one of C1-C20 straight-chain or branched alkylene or C3-C30 cycloalkylene.

[0021] In this invention, the polyisocyanate composition may also contain any one or a combination of at least two of the following: iminooxadiazine dione group, biuret group, ureidone group, carbamate group, ureocarbamate group, or ureaketimino group.

[0022] The structure of the iminooxadiazine dione group is as follows: The structure of the biuret group is: The structure of the diketone group is: The structure of the urethane group is: The structure of the urea-formate group is: The structure of the urea-ketone imine group is as follows: in The linking sites of the representative groups. All of the above structures can be detected by carbon NMR spectroscopy.

[0023] The following are preferred technical solutions of the present invention, but are not intended to limit the technical solutions provided by the present invention. The purpose and beneficial effects of the present invention can be better achieved and realized through the following preferred technical solutions.

[0024] As a preferred technical solution, the aromatic diisocyanate includes any one or a combination of at least two of toluene diisocyanate, diphenylmethane diisocyanate, or isophthalic diisocyanate.

[0025] Preferably, the toluene diisocyanate includes any one or a combination of at least two of toluene-2,3-diisocyanate, toluene-2,4-diisocyanate, toluene-2,5-diisocyanate, toluene-2,6-diisocyanate, toluene-3,4-diisocyanate, or toluene-3,5-diisocyanate.

[0026] Preferably, the aliphatic diisocyanate includes any one or a combination of at least two of the following: tetramethylene-1,4-diisocyanate, pentamethylene-1,5-diisocyanate, hexamethylene-1,6-diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, or cyclohexanedimethylene diisocyanate.

[0027] Preferably, based on the total mass of isocyanurate groups in the polyisocyanate composition being 100%, the mass of isocyanurate groups contained in the aliphatic diisocyanate modifier is >0 and ≤8%, for example, it can be 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, 5.5%, 6%, 6.5%, 7%, 7.5%, 8%, etc.

[0028] Preferably, based on the total mass of isocyanurate groups in the polyisocyanate composition as 100%, the mass of isocyanurate groups contained in the aliphatic diisocyanate modifier is >0 and ≤5%, for example, it can be 0.1%, 0.3%, 0.6%, 0.9%, 1.2%, 1.6%, 1.8%, 2.2%, 2.4%, 2.6%, 2.8%, 3.2%, 3.4%, 3.6%, 3.8%, 4.2%, 4.6%, 4.8%, etc.

[0029] Controlling the mass percentage of isocyanurate groups in the aliphatic diisocyanate modifier within a suitable range is beneficial to further improve the yellowing resistance of the polyurethane coating composition, while also taking into account better drying properties and pendulum hardness.

[0030] Preferably, the polyisocyanate composition further includes an organic solvent.

[0031] Preferably, the organic solvent includes any one or a combination of at least two of ethyl acetate, n-propyl acetate, isopropyl acetate, butyl acetate, or propylene glycol methyl ether acetate.

[0032] Preferably, the solid content of the polyisocyanate composition is 50-75%, for example, it can be 50%, 52%, 55%, 58%, 60%, 62%, 65%, 68%, 70%, 72%, 75%, etc.

[0033] Preferably, the viscosity of the polyisocyanate composition at 25°C is 500-4000 cP, for example, it can be 500 cP, 800 cP, 1000 cP, 1200 cP, 1500 cP, 1800 cP, 2000 cP, 2200 cP, 2500 cP, 2800 cP, 3000 cP, 3200 cP, 3400 cP, 3600 cP, 3800 cP, 4000 cP, etc.

[0034] Preferably, the isocyanate group content of the polyisocyanate composition is 8-15% by mass, for example, it can be 8%, 8.5%, 9%, 9.5%, 10%, 10.5%, 11%, 11.5%, 12%, 12.5%, 13%, 13.5%, 14%, 14.5%, etc.

[0035] In a second aspect, the present invention provides a method for preparing the polyisocyanate composition as described in the first aspect, the method comprising the following steps:

[0036] (1) Aliphatic diisocyanate reacts with some aromatic diisocyanate to obtain reaction solution A;

[0037] (2) The reaction solution A reacts with the remaining aromatic diisocyanate to obtain the polyisocyanate composition.

[0038] Preferably, the molar ratio of the aliphatic diisocyanate to the aromatic diisocyanate is (1.5-6):1, for example, it can be 1.55:1, 1.6:1, 2:1, 2.5:1, 2.8:1, 3:1, 3.2:1, 3.4:1, 3.5:1, 3.8:1, 4:1, 4.2:1, 4.5:1, 4.8:1, 5:1, 5.2:1, 5.4:1, 5.6:1, 5.8:1, 6:1, etc.

[0039] Preferably, the molar ratio of the aliphatic diisocyanate to the aromatic diisocyanate is (2.5-4.5):1, for example, it can be 2.5:1, 2.6:1, 2.8:1, 3:1, 3.2:1, 3.4:1, 3.6:1, 3.8:1, 4:1, 4.2:1, 4.4:1, 4.5:1, etc.

[0040] Preferably, based on the total mass of the aliphatic diisocyanate as 100%, the mass of the aromatic diisocyanate in step (1) is 1-10%, for example, it can be 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, 5.5%, 6%, 6.5%, 7%, 7.5%, 8%, 8.5%, 9%, 9.5%, etc.

[0041] Preferably, the reaction time in step (1) is 5-30 min, for example, it can be 5 min, 6 min, 8 min, 10 min, 12 min, 14 min, 16 min, 18 min, 20 min, 22 min, 24 min, 26 min, 28 min, 30 min, etc.

[0042] Preferably, the reaction temperature in step (1) is 10-150℃, such as 10℃, 20℃, 30℃, 40℃, 50℃, 60℃, 70℃, 80℃, 90℃, 100℃, 110℃, 120℃, 130℃, 140℃, 150℃, etc.

[0043] Preferably, the reaction in step (1) is carried out in the presence of a catalyst.

[0044] Preferably, the mass of the catalyst is 0.001-0.1% (e.g., 0.001%, 0.002%, 0.004%, 0.006%, 0.008%, 0.01%, 0.02%, 0.04%, 0.06%, 0.08%, 0.1%, etc.) based on the total mass of the aliphatic diisocyanate and aromatic diisocyanate being 100%, more preferably 0.005-0.05 wt%.

[0045] Preferably, the catalyst comprises any one or a combination of at least two of the following: quaternary ammonium hydroxide, quaternary ammonium carboxylate, a compound containing an aminomethylsilyl group, a tertiary amine compound, or a Mannich base compound.

[0046] Preferably, the quaternary ammonium hydroxide includes any one or a combination of at least two of tetramethylammonium hydroxide, benzyltrimethylammonium hydroxide, tetraethylammonium hydroxide, dimethylethylcyclohexylammonium hydroxide, and their hydrates.

[0047] Preferably, the quaternary ammonium carboxylates include any one or a combination of at least two of the following: 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, trimethylbenzylammonium hydroxide-octanoate, or 2-hydroxypropyltrimethylisooctanoate ammonium salt.

[0048] Preferably, the compound containing aminosilyl groups includes any one or a combination of at least two of hexamethyldisilazane, silylamine, or heptamethyldisilazane.

[0049] Preferably, the tertiary amine compound includes triethylamine and / or tripropylamine.

[0050] Preferably, the Mannich base compound includes tris(N,N-dimethylaminomethyl)phenol.

[0051] Preferably, the reaction temperature in step (2) is 10-150℃ (e.g., 10℃, 20℃, 30℃, 40℃, 50℃, 60℃, 70℃, 80℃, 90℃, 100℃, 110℃, 120℃, 130℃, 140℃, 150℃, etc.), more preferably 30-79℃, and even more preferably 45-75℃; the reaction at the preferred temperature can ensure good operational safety.

[0052] Preferably, in step (2), when the viscosity of the reaction system reaches 40-130 cP at 25°C (e.g., 40 cP, 45 cP, 50 cP, 55 cP, 60 cP, 65 cP, 70 cP, 75 cP, 80 cP, 85 cP, 90 cP, 95 cP, 100 cP, 105 cP, 110 cP, 115 cP, 120 cP, 125 cP, etc.), a terminator is added.

[0053] In the process of preparing the polyisocyanate composition, step (2) monitors the viscosity of the reaction system. When the viscosity at 25°C is >130 cP, the viscosity of the prepared polyisocyanate composition is often too high, which has an adverse effect on the convenience of downstream construction and the leveling of the paint film. When the viscosity is <40 cP, it often leads to problems such as low conversion rate, large monomer consumption and increased energy consumption for subsequent monomer removal, and low functionality of the polyisocyanate composition.

[0054] Preferably, the terminating agent comprises a protic acid and / or an acylation agent.

[0055] Preferably, the protic acid includes any one or a combination of at least two of phosphoric acid, benzoic acid, diisooctyl phosphate, p-toluenesulfonic acid, or di-n-butyl phosphate.

[0056] Preferably, the acylating agent comprises isophthalic acid dichloroisophthalate.

[0057] Those skilled in the art will understand that different types of catalysts used in the reaction system will result in different amounts of terminator. In the reaction system of the present invention, the amount of terminator added is determined to deactivate the catalyst in the reaction system.

[0058] After the terminator is added, the process further includes the sequential steps of removing unreacted diisocyanate and diluting with an organic solvent.

[0059] In this invention, the method for removing unreacted diisocyanate includes removal using a single-stage or multi-stage evaporator, such that the mass of residual diisocyanate in the polyisocyanate composition is less than 0.5% of the mass of the polyisocyanate composition.

[0060] Thirdly, the present invention provides the use of the polyisocyanate composition as described in the first aspect in polyurethane materials.

[0061] Preferably, the polyisocyanate composition is used as a crosslinking agent in a two-component polyurethane coating composition.

[0062] Fourthly, the present invention provides a two-component polyurethane coating composition comprising component A and component B; component A comprising a polyisocyanate composition as described in the first aspect; and component B comprising at least one hydroxyl-containing resin.

[0063] Preferably, the hydroxyl-containing resin includes any one or a combination of at least two of the following: polyether polyol, polyester polyol, polyurethane polyol, polysiloxane polyol, polycarbonate polyol, polyether polyamine, polyaspartic acid, polybutadiene polyol, polyacrylate polyol, or polyacrylic acid polyol.

[0064] In addition to containing the polyisocyanate composition provided by the present invention, the other components and their amounts in the two-component polyurethane coating composition can be selected in accordance with the conventional methods for two-component polyurethane coating compositions, and there are no particular restrictions on this.

[0065] Preferably, in the two-component polyurethane coating composition, the molar ratio of the isocyanate group of the polyisocyanate composition to the hydroxyl group of the hydroxyl-containing resin is 1:(0.9-1.1), for example, it can be 1:0.92, 1:0.94, 1:0.96, 1:0.98, 1:1, 1:1.02, 1:1.04, 1:1.06, 1:1.08, etc.

[0066] In some embodiments, in the two-component polyurethane coating composition, other components may be added to component A and / or component B according to application requirements, such as leveling agents, other auxiliaries, additives, etc. The specific selection and dosage of other components can be determined according to actual application requirements.

[0067] Compared with the prior art, the present invention has the following beneficial effects:

[0068] Applying the polyisocyanate composition provided by this invention to a polyurethane coating composition can give the coating excellent resistance to yellowing, while also achieving good pendulum hardness and drying properties; the yellowing resistance index of the coating is 2.2-3.2, the pendulum hardness is 0.71-0.78, and the drying time is 195-256 min. Detailed Implementation

[0069] To facilitate understanding of the present invention, the following embodiments are provided. Those skilled in the art should understand that these embodiments are merely illustrative and should not be construed as limiting the scope of the invention.

[0070] The sources of some components in the examples and comparative examples are as follows:

[0071] (1) HDI: Hexamethylene-1,6-diisocyanate, Wanhua Chemical Group Co., Ltd.;

[0072] (2) PDI: Pentamethylene-1,5-diisocyanate, Wanhua Chemical Group Co., Ltd.;

[0073] (3) IPDI: Isophorone diisocyanate, Wanhua Chemical Group Co., Ltd.

[0074] (4) H6XDI: Cyclohexanedimethyl diisocyanate, Wanhua Chemical Group Co., Ltd.;

[0075] (5) TDI-80: Toluene diisocyanate, containing approximately 80% 2,4-toluene diisocyanate and 20% 2,6-toluene diisocyanate, Wanhua Chemical Group Co., Ltd.

[0076] (6) TDI-100: Toluene diisocyanate, containing approximately 100% 2,4-toluene diisocyanate, Wanhua Chemical Group Co., Ltd.

[0077] (7)XDI: m-phenylenedimethyl diisocyanate, Wanhua Chemical Group Co., Ltd.;

[0078] (8) 2-Hydroxypropyltrimethylisooctanoate ammonium salt: Evonik;

[0079] (9) Benzyltrimethylammonium hydroxide: Inocare Technology Co., Ltd.;

[0080] (10) Dibutyl phosphate: Aladdin Reagent Company;

[0081] (11) p-Toluenesulfonic acid: Aladdin Reagent Company;

[0082] (12) Hydroxyl-containing resin: HS-129 / 70AB, Sabis HS- Ltd.

[0083] Where specific experimental steps or conditions are not specified in the examples, they can be performed according to the corresponding conventional experimental steps or conditions in this technical field; reagents or instruments whose manufacturers are not specified can be obtained by purchase.

[0084] Example 1

[0085] A polyisocyanate composition comprising an HDI modified body, an HDI-TDI modified body, and a TDI modified body; wherein, based on the total mass of isocyanurate groups in the polyisocyanate composition being 100%, the mass of isocyanurate groups contained in the HDI modified body is 1.6%.

[0086] The preparation method of the polyisocyanate composition includes the following steps:

[0087] (1) Add 1010g HDI and 50g TDI-100 to the reactor, stir and heat to 60℃ under nitrogen atmosphere, add 1.02g n-butanol solution of 20% 2-hydroxypropyltrimethylisooctanoate ammonium salt dropwise to the system, react for 10min to obtain reaction solution A;

[0088] (2) Add 300g of TDI-100 dropwise to the reaction solution A. After the addition is complete, the reaction is carried out at 60°C, and the viscosity of the reaction solution is monitored and measured. When the viscosity reaches 60cP / 25°C, 0.20g of di-n-butyl phosphate is added to terminate the reaction. The reaction solution is separated using a short-path evaporator (separation temperature 160°C, pressure 30Pa) to remove unreacted diisocyanate. The heavy components are dissolved in butyl acetate to obtain the polyisocyanate composition.

[0089] Example 2

[0090] A polyisocyanate composition comprising a PDI-modified body, a PDI-TDI-modified body, and a TDI-modified body; wherein, based on the total mass of isocyanurate groups in the polyisocyanate composition being 100%, the mass of isocyanurate groups contained in the PDI-modified body is 0.8%.

[0091] The preparation method of the polyisocyanate composition includes the following steps:

[0092] (1) Add 780g PDI and 50g TDI-100 to the reactor, stir and heat to 55°C under nitrogen atmosphere, add 0.28g of 20% n-butanol solution of 2-hydroxypropyltrimethylisooctanoate ammonium salt dropwise to the system, react for 5min to obtain reaction solution A;

[0093] (2) Add 300g of TDI-100 dropwise to the reaction solution A. After the addition is complete, the reaction is carried out at 55°C, and the viscosity of the reaction solution is monitored and measured. When the viscosity reaches 42cP / 25°C, 0.05g of di-n-butyl phosphate is added to terminate the reaction. The reaction solution is separated using a short-path evaporator (separation temperature 150°C, pressure 24Pa) to remove unreacted diisocyanate. The heavy component is dissolved in butyl acetate to obtain the polyisocyanate composition.

[0094] Example 3

[0095] A polyisocyanate composition comprising a PDI modified body, a PDI-XDI modified body, and an XDI modified body; wherein, based on the total mass of isocyanurate groups in the polyisocyanate composition being 100%, the mass of isocyanurate groups contained in the PDI modified body is 2.4%.

[0096] The preparation method of the polyisocyanate composition includes the following steps:

[0097] (1) Add 780g PDI and 64g XDI to the reactor, stir and heat to 70°C under nitrogen atmosphere, add 1.07g of 25% benzyltrimethylammonium hydroxide methanol solution dropwise to the system, react for 15min to obtain reaction solution A;

[0098] (2) Add 500g of XDI dropwise to the reaction solution A. After the addition is complete, the reaction is carried out at 70°C, and the viscosity of the reaction solution is monitored and measured. When the viscosity reaches 89cP / 25°C, 0.27g of di-n-butyl phosphate is added to terminate the reaction. The reaction solution is separated using a short-path evaporator (separation temperature 165°C, pressure 14Pa) to remove unreacted diisocyanate. The heavy component is dissolved in butyl acetate to obtain the polyisocyanate composition.

[0099] Example 4

[0100] A polyisocyanate composition comprising an IPDI modified body, an IPDI-TDI modified body, and a TDI modified body; wherein, based on the total mass of isocyanurate groups in the polyisocyanate composition being 100%, the mass of isocyanurate groups contained in the IPDI modified body is 8.4%.

[0101] The preparation method of the polyisocyanate composition includes the following steps:

[0102] (1) Add 1332g IPDI and 10g TDI-80 to the reactor, stir and heat to 80℃ under nitrogen atmosphere, add 3.76g n-butanol solution of 20% 2-hydroxypropyltrimethylisooctanoate ammonium salt dropwise to the system, react for 25min to obtain reaction solution A;

[0103] (2) TDI-80 164g was added dropwise to the reaction solution A. After the addition was complete, the reaction was carried out at 80°C, and the viscosity of the reaction solution was monitored and measured. When the viscosity reached 108cP / 25°C, 0.75g of p-toluenesulfonic acid was added to terminate the reaction. The reaction solution was separated using a short-path evaporator (separation temperature 185°C, pressure 24Pa) to remove unreacted diisocyanate. The heavy component was dissolved in butyl acetate to obtain the polyisocyanate composition.

[0104] Example 5

[0105] A polyisocyanate composition comprising an H6XDI modified body, a TDI modified body, and an H6XDI-TDI modified body; wherein, based on the total mass of isocyanurate groups in the polyisocyanate composition being 100%, the H6XDI modified body contains 5.3% isocyanurate groups.

[0106] The preparation method of the polyisocyanate composition includes the following steps:

[0107] (1) Add 970g H6XDI and 20g TDI-80 to the reactor, stir and heat to 75°C under nitrogen atmosphere, add 2.29g n-butanol solution of 20% 2-hydroxypropyltrimethylisooctanoate ammonium salt dropwise to the system, react for 30min to obtain reaction solution A;

[0108] (2) Add 154g of TDI-80 to the reaction solution A dropwise. After the addition is complete, the reaction is carried out at 75°C, and the viscosity of the reaction solution is monitored and measured. When the viscosity reaches 128cP / 25°C, 0.46g of p-toluenesulfonic acid is added to terminate the reaction. The reaction solution is separated using a short-path evaporator (separation temperature 180°C, pressure 20Pa) to remove unreacted diisocyanate. The heavy component is dissolved in butyl acetate to obtain the polyisocyanate composition.

[0109] Example 6

[0110] A polyisocyanate composition comprising an HDI modified body, an XDI modified body, and an HDI-XDI modified body; wherein, based on the total mass of isocyanurate groups in the polyisocyanate composition being 100%, the HDI modified body contains 6.3% isocyanurate groups by mass.

[0111] The preparation method of the polyisocyanate composition includes the following steps:

[0112] (1) Add 1010g HDI and 30g XDI to the reactor, stir and heat to 65°C under nitrogen atmosphere, add 1.73g n-butanol solution of 20% 2-hydroxypropyltrimethylisooctanoate ammonium salt dropwise to the system, react for 8min to obtain reaction solution A;

[0113] (2) Add 346g of XDI dropwise to the reaction solution A. After the addition is complete, the reaction is carried out at 65°C, and the viscosity of the reaction solution is monitored and measured. When the viscosity reaches 65cP / 25°C, 0.35g of di-n-butyl phosphate is added to terminate the reaction. The reaction solution is separated using a short-path evaporator (separation temperature 180°C, pressure 20Pa) to remove unreacted diisocyanate. The heavy component is dissolved in butyl acetate to obtain the polyisocyanate composition.

[0114] Example 7

[0115] A polyisocyanate composition comprising an HDI modified body, an HDI-TDI modified body, and a TDI modified body; wherein, based on the total mass of isocyanurate groups in the polyisocyanate composition being 100%, the mass of isocyanurate groups contained in the HDI modified body is 1.2%.

[0116] The preparation method of the polyisocyanate composition includes the following steps:

[0117] (1) Add 336g HDI and 16.5g TDI-100 to the reactor, stir and heat to 60°C under nitrogen atmosphere, add 0.51g n-butanol solution of 20% 2-hydroxypropyltrimethylisooctanoate ammonium salt dropwise to the system, react for 10min to obtain reaction solution A;

[0118] (2) Add 33.5 g of TDI-1003 dropwise to the reaction solution A. After the addition is complete, the reaction is carried out at 60°C, and the viscosity of the reaction solution is monitored and measured. When the viscosity reaches 60 cP / 25°C, 0.15 g of di-n-butyl phosphate is added to terminate the reaction. The reaction solution is separated using a short-path evaporator (separation temperature 160°C, pressure 30 Pa) to remove unreacted diisocyanate. The heavy component is dissolved in butyl acetate to obtain the polyisocyanate composition.

[0119] Example 8

[0120] A polyisocyanate composition comprising an HDI modified body, an HDI-TDI modified body, and a TDI modified body; wherein, based on the total mass of isocyanurate groups in the polyisocyanate composition being 100%, the mass of isocyanurate groups contained in the HDI modified body is 2.2%.

[0121] The preparation method of the polyisocyanate composition includes the following steps:

[0122] (1) Add 2688g HDI and 132g TDI-100 to the reactor, stir and heat to 60°C under nitrogen atmosphere, add 1.23g n-butanol solution of 20% 2-hydroxypropyltrimethylisooctanoate ammonium salt dropwise to the system, react for 10min to obtain reaction solution A;

[0123] (2) Add 18g of TDI-1002 to the reaction solution A. After the addition is complete, the reaction is carried out at 60°C and the viscosity of the reaction solution is monitored. When the viscosity reaches 60cP / 25°C, add 0.24g of di-n-butyl phosphate to terminate the reaction. Use a short-path evaporator (separation temperature 160°C, pressure 30Pa) to separate the reaction solution and remove unreacted diisocyanate. Dissolve the heavy component with butyl acetate to obtain the polyisocyanate composition.

[0124] Comparative Example 1

[0125] A polyisocyanate composition comprising an HDI modified body, a TDI modified body, and an HDI-TDI modified body, wherein the HDI modified body contains 17.4% isocyanurate groups based on the total mass of isocyanurate groups in the polyisocyanate composition being 100%.

[0126] The preparation method of the polyisocyanate composition includes the following steps:

[0127] (1) Add 1010g HDI to the reactor, stir and heat to 60℃ under nitrogen atmosphere, add 1.02g n-butanol solution of 20% 2-hydroxypropyltrimethylisooctanoate ammonium salt dropwise to the system, react for 10min to obtain reaction solution A;

[0128] (2) Add 350g of TDI to the reaction solution A. After the addition is complete, the reaction is carried out at 60°C and the viscosity of the reaction solution is monitored. When the viscosity reaches 60cP / 25°C, add 0.20g of di-n-butyl phosphate to terminate the reaction. The reaction solution is separated using a short-path evaporator (separation temperature 160°C, pressure 30Pa) to remove unreacted diisocyanate. The heavy component is dissolved in butyl acetate to obtain the polyisocyanate composition.

[0129] Comparative Example 2

[0130] A polyisocyanate composition comprising a TDI modifier;

[0131] The method for preparing the polyisocyanate composition includes:

[0132] 700g of TDI was added to a reaction vessel, and the mixture was stirred and heated to 60°C under a nitrogen atmosphere. 1.02g of a 20% n-butanol solution of 2-hydroxypropyltrimethylisooctanoate ammonium salt was added dropwise to the system. After the addition was complete, the viscosity of the reaction solution was monitored. When the viscosity reached 60cP / 25°C, 0.20g of di-n-butyl phosphate was added to terminate the reaction. The reaction solution was separated using a short-path evaporator (separation temperature 160°C, pressure 30Pa) to remove unreacted isocyanate monomers. The heavy components were dissolved in butyl acetate to obtain the polyisocyanate composition.

[0133] Product Indicators

[0134] (1) NCO% (mass percentage of isocyanate groups): determined according to GB / T 12009.4-2016;

[0135] (2) Viscosity: The viscosity was obtained at 25°C using a BrookField DV-IPrime viscometer with an S21 rotor.

[0136] (3) The percentage of isocyanurate groups in the aliphatic diisocyanate modifier relative to the total mass of isocyanurate groups in the polyisocyanate composition: determined by gel permeation chromatography using polystyrene as a standard and tetrahydrofuran as the eluent, according to GB / T27810-2011; the specific test conditions are as follows:

[0137] GPC equipment: Agilent 1260

[0138] GPC pillars: PL1113-6520 and PL113-6325 (Agilent)

[0139] Sample concentration: 3wt%

[0140] Mobile phase: Tetrahydrofuran

[0141] Detection method: Differential detector

[0142] Flow rate: 1 mL / min

[0143] Column temperature: 35℃

[0144] The standard curve uses polystyrene with a molecular weight of 162-17900.

[0145] The basic properties of the polyisocyanate compositions provided in Examples 1-8 and Comparative Examples 1-2 are listed in Table 1:

[0146] Table 1

[0147]

[0148] The ratios in Table 1 represent the percentage of the mass of isocyanurate groups in the aliphatic diisocyanate modifier relative to the total mass of isocyanurate groups in the polyisocyanate composition.

[0149] Performance testing

[0150] The polyisocyanate compositions provided in Examples 1-8 and Comparative Examples 1-2 were mixed with hydroxyl-containing resin (Sabis HS-129 / 70AB) at an NCO / OH molar ratio of 1:1, and then diluted with a mixed solvent of ethyl acetate / xylene (mass ratio of 1:1) to prepare paints. The total mass ratio of the polyisocyanate composition and the hydroxyl-containing resin to the mixed solvent was 1:1. The prepared paints were named Paint 1, Paint 2, Paint 3, Paint 4, Paint 5, Paint 6, Paint 7, Paint 8, Paint A, and Paint B, respectively. The obtained paints were tested according to the following method, and the test results are shown in Table 2.

[0151] (1) Yellowing resistance: The above paint was applied to a tinplate coated with white primer using a 150μm wire rod, with a coating thickness of 25-30μm. After being left at room temperature for 7 days, the yellowing resistance of the paint film was tested. A 313nm wavelength ultraviolet lamp with a light intensity of 200mW / cm² was used. 2 Irradiate for 60 seconds, test the initial L0, a0, b0 of the paint film and the L, a, b of the paint film after UV irradiation, and calculate the color difference value according to the following formula:

[0152] ΔE=[(L-L0) 2 +(a-a0) 2 +(b-b0) 2 ] 0.5 ,

[0153] Where L represents the brightness after irradiation, and L0 represents the brightness before irradiation; a represents the red-green hue after irradiation, and a0 represents the red-green hue before irradiation; b represents the yellow-blue hue after irradiation, and b0 represents the yellow-blue hue before irradiation.

[0154] (2) Steering rod hardness: In accordance with GB / T 1730, the base material used is glass plate;

[0155] (3) Drying time: The drying time was tested according to the national standard GB / T 1728 using a linear drying time recorder (manufacturer: Biaogeda, model: BGD261);

[0156] Table 2

[0157] Paint 1 2.2 0.74 232 Paint 2 2.4 0.73 214 Paint 3 2.2 0.71 242 Paint 4 2.8 0.77 202 Paint 5 2.8 0.78 223 Paint 6 2.3 0.72 256 Paint 7 3.2 0.76 195 Paint 8 2.4 0.71 265 Paint A 2.2 0.61 288 Paint B 4.0 0.79 181

[0158] The test results in Tables 1 and 2 show that in paints 1-6 obtained using the polyisocyanate compositions provided in Examples 1-6, the mass percentage of isocyanurate groups in the aliphatic diisocyanate modifier is >0 and ≤10%, and the final paints all achieve excellent resistance to yellowing, pendulum hardness, and drying time. The paint obtained using the polyisocyanate composition provided in Example 7 has slightly poor resistance to yellowing. The paint obtained using the polyisocyanate composition provided in Example 8 has slightly poor drying performance. The paint obtained using the polyisocyanate composition provided in Comparative Example 1 has poor pendulum hardness and drying performance. The paint obtained using the polyisocyanate composition provided in Comparative Example 2 has significantly poor resistance to yellowing.

[0159] The applicant declares that the detailed process equipment and process flow of this invention are illustrated through the above embodiments, but this invention is not limited to the above detailed process equipment and process flow, that is, it does not mean that this invention must rely on the above detailed process equipment and process flow to be implemented. Those skilled in the art should understand that any improvements to this invention, equivalent substitutions of raw materials for the products of this invention, additions of auxiliary components, and selection of specific methods, all fall within the protection scope and disclosure scope of this invention.

Claims

1. A polyisocyanate composition, characterized in that, The polyisocyanate composition includes aliphatic diisocyanate modifiers, aliphatic-aromatic diisocyanate modifiers, and optionally aromatic diisocyanate modifiers; The aliphatic diisocyanate modified body is obtained by reacting aliphatic diisocyanates; the aliphatic diisocyanate modified body comprises at least one of the following compounds: 、 ； R1 is independently selected from any one of C1-C20 straight-chain or branched alkylene groups and C3-C30 cycloalkylene groups; n is selected from an integer ≥0; R1 can be the same or different; The aromatic diisocyanate modified body is obtained by reacting aromatic diisocyanates; The aromatic diisocyanate modifier comprises at least one of the following compounds: 、 ； Wherein, R2 is independently selected from any one of C6-C30 arylene groups; m is selected from integers ≥0; R2 can be the same or different; The aliphatic-aromatic diisocyanate modified product is obtained by reacting aliphatic diisocyanate with aromatic diisocyanate; The aliphatic-aromatic diisocyanate modifier comprises at least one of the following compounds: 、 ； Wherein, each of R3 is independently selected from any one of C6-C30 arylene, C1-C20 straight-chain or branched alkylene, and C3-C30 cycloalkylene; p is selected from an integer ≥0; and at least one R3 is selected from any one of C6-C30 arylene, and at least one R3 is selected from any one of C1-C20 straight-chain or branched alkylene or C3-C30 cycloalkylene; The aliphatic diisocyanate is an aliphatic diisocyanate and / or an alicyclic diisocyanate; based on the total mass of isocyanurate groups in the polyisocyanate composition being 100%, the mass of isocyanurate groups contained in the aliphatic diisocyanate modifier is >0 and ≤10%.

2. The polyisocyanate composition according to claim 1, characterized in that, The aromatic diisocyanate includes any one or a combination of at least two of toluene diisocyanate, diphenylmethane diisocyanate or isophthalic diisocyanate; The aliphatic diisocyanate includes any one or a combination of at least two of the following: tetramethylene-1,4-diisocyanate, pentamethylene-1,5-diisocyanate, hexamethylene-1,6-diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, or cyclohexanedimethylene diisocyanate.

3. The polyisocyanate composition according to claim 1, characterized in that, Based on the total mass of isocyanurate groups in the polyisocyanate composition being 100%, the mass of isocyanurate groups contained in the aliphatic diisocyanate modifier is >0 and ≤8%.

4. The polyisocyanate composition according to claim 3, characterized in that, Based on the total mass of isocyanurate groups in the polyisocyanate composition being 100%, the mass of isocyanurate groups contained in the aliphatic diisocyanate modifier is >0 and ≤5%.

5. The polyisocyanate composition according to claim 1, characterized in that, The polyisocyanate composition also includes an organic solvent; The solid content of the polyisocyanate composition is 50-75%; The viscosity of the polyisocyanate composition at 25°C is 500-4000 cP; The isocyanate group content of the polyisocyanate composition is 8-15% by mass.

6. A method for preparing the polyisocyanate composition according to any one of claims 1-5, characterized in that, The preparation method includes the following steps: (1) Aliphatic diisocyanate reacts with some aromatic diisocyanate to obtain reaction solution A; Based on the total mass of the aliphatic diisocyanate being 100%, the mass of the aromatic diisocyanate in step (1) is 1-10%; (2) The reaction solution A reacts with the remaining aromatic diisocyanate to obtain the polyisocyanate composition; when the reaction in step (2) proceeds to the point where the viscosity of the reaction system is 40-130 cP at 25°C, a terminator is added; the molar ratio of the aliphatic diisocyanate to the aromatic diisocyanate is (1.5-6):

1.

7. The preparation method according to claim 6, characterized in that, The reaction time in step (1) is 5-30 min; The reaction temperature in step (1) is 10-150℃; The reaction described in step (1) is carried out in the presence of a catalyst; The mass of the catalyst is 0.001-0.1%, based on the total mass of the aliphatic diisocyanate and aromatic diisocyanate being 100%.

8. The preparation method according to claim 6, characterized in that, The reaction temperature in step (2) is 10-150℃; After the terminator is added, the process further includes the sequential steps of removing unreacted diisocyanate and diluting with an organic solvent.

9. The use of a polyisocyanate composition as described in any one of claims 1-5 in polyurethane materials.

10. A two-component polyurethane coating composition, characterized in that, The two-component polyurethane coating composition includes component A and component B; Component A comprises the polyisocyanate composition as described in any one of claims 1-5; Component B includes at least one hydroxyl-containing resin.

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