Polyisocyanate composition as well as preparation method and application thereof

Abstract

The invention provides a polyisocyanate composition and a preparation method thereof. The composition comprises a mixture of the following components. > = 50% by weight, based on the total weight of the mixture, of at least one polyisocyanurate based on pentamethylene diisocyanate and < = 50% by weight, based on the total weight of the mixture, of at least one polyisocyanate based on hexamethylene diisocyanate and / or of at least one polyisocyanurate based on pentamethylene diisocyanate and hexamethylene diisocyanate a polyisocyanate of an ester, wherein the polyisocyanate composition has a residual monomer content of the monomeric diisocyanate of less than 0.1 wt% based on the total weight of the polyisocyanate composition. According to the solvent-free polyisocyanate composition containing the low-viscosity HDI polyisocyanate and the low-monomer-amount polyisocyanurate based on pentamethylene diisocyanate, the viscosity of the polyisocyanate composition can be improved, the solvent-free polyisocyanate composition has more balanced and excellent solvent wiping resistance and drying performance, and meanwhile, the compatibility is improved.

Description

Technical Field

[0001] This invention relates to a polyisocyanurate as a raw material for preparing polyurethane resin. Background Technology

[0002] Polyurethane resins are typically manufactured by reacting polyisocyanates with compounds containing active hydrogen groups, and are widely used in various industries, such as as coatings, adhesives, and elastomers.

[0003] Polyisocyanates used in the manufacture of polyurethane resins, such as hexamethylene diisocyanate (HDI) and pentamethylene diisocyanate (PDI), are known. In addition, the following literature proposes a method for using pentamethylene diisocyanate to derive isocyanurate oligomers, etc.

[0004] EP0524500A1 and EP0524201A1 disclose polyisocyanates based on aliphatic diisocyanates having 4-18 carbon atoms, wherein the ratio of urea carbamate groups to isocyanurate groups is >0.1 and <5, and have improved compatibility in the case of polyisocyanates containing urea carbamates.

[0005] JP2007-112936A discloses a monohydric alcohol-modified polyisocyanate composition, an isocyanurate trimer content of 60 to 95% by weight based on the total amount of isocyanate, and describes that a content of less than 60% by weight is detrimental to viscosity and therefore unfavorable to the usability of such polyisocyanate.

[0006] CN107406573A discloses linear, branched polyisocyanurate modified with 1 to 18 carbon atoms, wherein the equivalence ratio of urea ester groups to isocyanurate groups is >0 and ≤0.19, exhibiting good compatibility.

[0007] It is known that pentamethylene diisocyanate monomers contain 53.5% NCO by weight, and hexamethylene diisocyanate monomers contain 50% NCO by weight. Polyisocyanurates prepared from pentamethylene diisocyanate monomers have a higher isocyanate group content, resulting in better solvent resistance and drying performance. However, their viscosity is relatively high, and alcohol-free pentamethylene diisocyanate-based polyisocyanates have poor compatibility. Polyisocyanates based on hexamethylene diisocyanates are known to have low viscosity and good compatibility, but their drying performance and solvent-resistant wiping properties are poor. Furthermore, the quick-drying properties of polyurethane resins obtained from the polyisocyanates described in the aforementioned patent literature are insufficient. In various industrial sectors, there is a demand for further improvements in the solvent-resistant wiping properties of polyurethane resins.

[0008] Therefore, it is necessary to provide a polyisocyanate composition of a polyurethane resin with excellent quick-drying properties, improved solvent resistance and good compatibility. Summary of the Invention

[0009] The inventors made an unexpected discovery: a polyisocyanate composition of HDI polyisocyanate and a low monomer content polyisocyanurate based on pentamethylene diisocyanate can improve the viscosity of the polyisocyanate composition, and has more balanced and excellent solvent resistance and drying properties, while also improving compatibility.

[0010] In view of this, the present invention provides a polyisocyanate composition comprising a mixture of the following components: at least one polyisocyanate based on pentamethylene diisocyanate, ≥50% by weight of the total weight of the mixture, and at least one polyisocyanate based on hexamethylene diisocyanate, and / or at least one polyisocyanate based on pentamethylene diisocyanate and hexamethylene diisocyanate, wherein the polyisocyanate composition has a residual monomer content of less than 0.1% by weight of monomeric diisocyanate based on the total weight of the polyisocyanate composition.

[0011] The polyisocyanate composition, wherein the mixture comprises ≥70% by weight, preferably ≥80% by weight, of at least one polyisocyanate based on pentamethylene diisocyanate, based on the total weight of the mixture, with the balance consisting of at least one polyisocyanate based on hexamethylene diisocyanate and / or at least one polyisocyanate based on both pentamethylene diisocyanate and hexamethylene diisocyanate.

[0012] The polyisocyanate composition, wherein the mixture comprises ≥2% by weight, preferably ≥5% by weight, particularly preferably ≥10% by weight, and most preferably ≥20% by weight of the at least one hexamethylene diisocyanate-based polyisocyanate and / or the at least one pentamethylene diisocyanate-based polyisocyanate and hexamethylene diisocyanate, based on the total weight of the mixture.

[0013] The polyisocyanate composition is formed of ≥60% by weight, preferably ≥70% by weight, of pentamethylene diisocyanate and hexamethylene diisocyanate in the polyisocyanate.

[0014] On the other hand, the present invention also provides a method for preparing the polyisocyanate composition, the method comprising the following steps: mixing the at least one pentamethylene diisocyanate-based polyisocyanate with the at least one hexamethylene diisocyanate-based polyisocyanate and / or at least one polyisocyanate based on pentamethylene diisocyanate and hexamethylene diisocyanate.

[0015] In this invention, one or more auxiliaries and additives may be added before, during, and / or after the mixing step.

[0016] The method for preparing the polyisocyanate composition, wherein the at least one polyisocyanate based on pentamethylene diisocyanate is preferably an isocyanurate oligomer of pentamethylene diisocyanate and unavoidably contained by-products, but does not contain any modified alcohol components.

[0017] The pentamethylene diisocyanate-based polyisocyanate of the present invention comprises pentamethylene diisocyanate isocyanurate oligomers. It should be noted that although the pentamethylene diisocyanate-based polyisocyanate of the present invention contains pentamethylene diisocyanate isocyanurate oligomers as a single main component, the polyisocyanate is permitted to contain unavoidable byproducts (e.g., catalysts, co-catalysts and stabilizers used in the manufacture of isocyanurate oligomers, iminooxadiazine dione derivatives of pentamethylene diisocyanate, pentamethylene diisocyanate monomers, etc.).

[0018] The isocyanurate oligomer of pentamethylene diisocyanate is a trimer of pentamethylene diisocyanate. The trimer includes isocyanurate oligomers as symmetrical trimers and iminooxadiazine dione derivatives as asymmetrical trimers. However, the polyisocyanurate of the present invention is basically formed from isocyanurate oligomers of pentamethylene diisocyanate. If it contains iminooxadiazine dione derivatives of pentamethylene diisocyanate, its content relative to the total amount of polyisocyanurate is, for example, 10% by weight or less, preferably 3% by weight or less, more preferably 1% by weight or less, and even more preferably 0.5% by weight or less.

[0019] Furthermore, in this invention, in the isocyanurate esterification reaction, compounds containing active hydrogen groups are not used as modifiers, and compounds containing active hydrogen groups are not used as modifiers to modify the isocyanurate oligomers; that is, isocyanurate oligomers are obtained only from pentamethylene diisocyanate.

[0020] Thus, polyisocyanurates based on pentemethylene diisocyanate can be obtained, especially polyisocyanurates containing isocyanurate oligomers formed solely from pentemethylene diisocyanate that have not been modified by compounds containing active hydrogen groups as modifiers (hereinafter, sometimes referred to as "unmodified").

[0021] If the isocyanurate is an isocyanurate oligomer containing unmodified pentamethylene diisocyanate, a polyurethane resin with excellent drying properties, improved solvent wiping resistance, and hardness can be obtained.

[0022] It should be noted that, in this invention, the so-called unmodified isocyanurate oligomer is defined as a derivative that does not actively incorporate a compound containing an active hydrogen group as a modifier. For example, it is permissible to contain: a modifying group (e.g., urea group, etc.) for pentamethylene diisocyanate oligomers, which is generated based on the compound containing an active hydrogen group that is inevitably mixed in during the manufacture of the isocyanurate oligomer (e.g., solvent of the isocyanurate esterification catalyst (e.g., water, etc.).

[0023] Regarding the permitted concentration of modifying groups in the isocyanurate oligomer of pentamethylene diisocyanate, for example, the following are permitted: modifying groups (e.g., urea groups) for the isocyanurate derivative of pentamethylene diisocyanate, generated based on compounds containing active hydrogen groups that inevitably mix in during the manufacture of isocyanurate derivatives (e.g., solvents for isocyanuration catalysts, such as water). The concentration relative to 1 g of the isocyanurate oligomer of pentamethylene diisocyanate is, for example, 0.03 mmol or less, preferably 0.01 mmol or less, and more preferably 0.005 mmol or less.

[0024] Unless otherwise specified, the isocyanurate oligomers referred to below are unmodified isocyanurate oligomers. For polyisocyanurates, the isocyanate group concentration (100% by weight of solid content) is, for example, 18.0% by weight or more, preferably 20.0% by weight or more, for example, 28.0% by weight or less, preferably 25.0% by weight or less.

[0025] The polyisocyanurate based on pentamethylene diisocyanate of the present invention is formed from isocyanurate oligomers of pentamethylene diisocyanate, and preferably the viscosity of the polyisocyanurate at 25°C is 4000 mPa·s or more and 50000 mPa·s or less.

[0026] For the polyisocyanurate of the pentamethylene diisocyanate of the present invention, it is more preferable that the viscosity at 25°C is 5000 mPa·s or more and 30000 mPa·s or less.

[0027] The invention provides a polyurethane resin with excellent quick-drying properties, solvent resistance, and hardness, based on pentamethylene diisocyanate.

[0028] Pentylene diisocyanate isocyanurate oligomers can be obtained by isocyanuration of pentylene diisocyanate in the presence of an isocyanuration catalyst. To detail the method for trimerizing pentylene diisocyanate, pentylene diisocyanate is heated to a certain temperature, a tertiary amine catalyst is added for monomer pretreatment, an isocyanurate catalyst is added to initiate the trimerization reaction, and a catalyst poisoning agent is added to terminate the reaction at the endpoint. The monomer is then separated from the reaction solution to obtain the final product containing PDI isocyanurate.

[0029] Furthermore, in the method for preparing PDI polyisocyanurate, the catalyst can be any catalyst that activates the isocyanurate esterification, without particular limitation. Examples include triethylamine, tributylamine, triethylenediamine, secondary amine copolymers (e.g., secondary amines such as dialkylamines, condensates with monomers that can copolymerize with secondary amines (e.g., phenol, formaldehyde, etc.), tertiary amines such as 2-dimethylaminomethylphenol, 2,4,6-tris(dimethylaminomethyl)phenol, and tetraalkylammonium hydroxides or their organic weak acid salts such as tetraethylammonium, tetrabutylammonium, trimethylbenzylammonium, and tributylbenzylammonium. Examples include hydroxides of trialkylhydroxyalkylammoniums such as trimethylhydroxypropylammonium, trimethylhydroxyethylammonium, triethylhydroxypropylammonium, and triethylhydroxyethylammonium, or their organic weak acid salts, such as metal salts of alkylcarboxylic acids such as acetic acid, hexanoic acid, octanoic acid, myristic acid, and naphthenic acid (e.g., alkali metal salts, magnesium salts, tin salts, zinc salts, lead salts, etc.). Preferably, catalysts that enable aliphatic diisocyanates to form modified isocyanurate ring structures are used, such as one or any mixture of several of benzyltrimethylformate quaternary ammonium salt, benzyltrimethylvalerate quaternary ammonium salt, benzyltrimethyloctanoate quaternary ammonium salt, and trimethylhydroxypropyloctanoate quaternary ammonium salt.

[0030] Furthermore, the quaternary ammonium salt of benzyltrimethylvalerate can be prepared by reacting a 40% aqueous solution of benzyltrimethylammonium hydroxide with valerate at a molar ratio of 1:1 at 30-80°C, then removing excess water by vacuum distillation, and diluting the catalyst component with a suitable solvent, such as ethyl acetate to 10wt%-50wt%, preferably ethyl acetate to 10wt% concentration.

[0031] When the above-described catalyst is used as the isocyanurate esterification catalyst, pentamethylene diisocyanate can be isocyanurized with a particularly excellent reaction rate, resulting in excellent manufacturing efficiency. The proportion of the isocyanurate esterification catalyst relative to 100 parts by weight of pentamethylene diisocyanate, converted to pure catalyst, is, for example, 0.005 parts by weight or more, preferably 0.02 parts by weight or more, for example, 0.1 parts by weight or less, preferably 0.06 parts by weight or less. Furthermore, in this method, the isocyanurate esterification reaction is carried out by adding the isocyanurate esterification catalyst to pentamethylene diisocyanate in the above proportion and heating.

[0032] As for the reaction conditions for the isocyanurate esterification reaction, for example, under an inert gas atmosphere such as nitrogen and at normal pressure (atmospheric pressure), the reaction temperature (the highest temperature reached) is, for example, 20°C or higher, preferably higher than 40°C, more preferably 60°C or higher, for example, 80°C or lower, and preferably 75°C or lower.

[0033] Furthermore, in the method for preparing PDI polyisocyanurate, the terminating agent is an acidic compound, preferably at least one selected from dimethyl phosphate, diethyl phosphate, dibutyl phosphate, dioctyl phosphate, 2-ethylhexyl phosphate, phosphoric acid, hydrochloric acid, benzenesulfonic acid, p-toluenesulfonic acid, benzoyl chloride, and acetyl chloride.

[0034] After the isocyanurate esterification reaction is completed, unreacted pentamethylene diisocyanate monomers are removed from the polyisocyanate containing pentamethylene diisocyanate oligomers, the mixed reaction solution with pentamethylene diisocyanate monomers, using known methods such as thin-film distillation. (If a reaction solvent and / or catalyst deactivator are used in conjunction, the reaction solvent and / or catalyst deactivator are also removed.) It should be noted that when preparing the mixture of polyisocyanate and pentamethylene diisocyanate monomers, unreacted pentamethylene diisocyanate monomers may not be removed, and the reaction mixture may be used directly as a mixture of polyisocyanate and pentamethylene diisocyanate monomers.

[0035] It should be noted that the distillation yield of polyisocyanurate can be determined in the following way:

[0036] Distillation yield of polyisocyanurate (wt%) = (weight of polyisocyanurate (g) / weight of reaction mixture (g)) × 100.

[0037] According to the examples described later, the weight ratio of polyisocyanurate to the weight of the reaction mixture was calculated.

[0038] In addition, the reaction conversion rate of isocyanate group concentration relative to the isocyanate group concentration of the feed liquid is calculated using the following formula. It should be noted that the conversion rate of isocyanate group is the conversion rate of isocyanurate.

[0039] The reaction conversion rate (wt%) of isocyanate group concentration = ((Isocyanate group concentration of the feed solution (wt%) - Isocyanate group concentration of the reaction mixture (wt%)) / Isocyanate group concentration of the feed solution (wt%)) × 100.

[0040] Furthermore, in this invention, in the isocyanurate esterification reaction, compounds containing active hydrogen groups are not used as modifiers, and compounds containing active hydrogen groups are not used as modifiers to modify the isocyanurate oligomers; that is, isocyanurate oligomers are obtained only from pentamethylene diisocyanate.

[0041] Thus, polyisocyanurates, especially polyisocyanurates containing isocyanurate oligomers formed solely from pentamethylene diisocyanate, can be obtained.

[0042] Polyisocyanurates containing isocyanurate oligomers of unmodified pentamethylene diisocyanate can produce polyurethane resins with excellent drying properties, improved solvent wiping resistance, and increased hardness.

[0043] It should be noted that, in this invention, the so-called unmodified isocyanurate oligomer is defined as a derivative that does not actively incorporate a compound containing an active hydrogen group as a modifier. For example, it is permissible to contain: a modifying group (e.g., urea group, etc.) for pentamethylene diisocyanate oligomers, which is generated based on the compound containing an active hydrogen group that is inevitably mixed in during the manufacture of the isocyanurate oligomer (e.g., solvent of the isocyanurate esterification catalyst (e.g., water, etc.).

[0044] The concentration of the modified groups allowed in the isocyanurate oligomer of pentamethylene diisocyanate is, for example, 0.03 mmol or less, preferably 0.01 mmol or less, and more preferably 0.005 mmol or less, relative to 1 g of the isocyanurate oligomer of pentamethylene diisocyanate.

[0045] It should be noted that the concentration of the modifying groups in the isocyanurate oligomer of pentamethylene diisocyanate can be, for example, determined by... 13 It was calculated by C-NMR measurement.

[0046] Unless otherwise specified, pentamethylene diisocyanate isocyanurate oligomers are unmodified isocyanurate oligomers. For polyisocyanurates, the isocyanate group concentration (100% by weight of solid content) is, for example, 18.0% by weight or more, preferably 20.0% by weight or more, for example, 28.0% by weight or less, preferably 25.0% by weight or less. Pentamethylene diisocyanate isocyanurate oligomers refer to oligomers generated from pentamethylene diisocyanate monomers that contain isocyanurate group structural units, wherein the isocyanurate groups are as follows:

[0047]

[0048] In addition, isocyanurate oligomers of pentamethylene diisocyanate include isocyanurate mononuclear molecules (specifically, compounds in which 3 molecules of pentamethylene diisocyanate form one isocyanurate ring, and this isocyanurate ring is not linked to other isocyanurate rings).

[0049] Its structural formula is shown below:

[0050]

[0051] That is, three molecules of pentamethylene diisocyanate formed by isocyanurate rings and polynuclear isocyanurate (e.g., isocyanurate dimer (specifically, a compound formed by combining one isocyanurate mononuclear with another isocyanurate mononuclear), isocyanurate trinuclear or more (specifically, a compound formed by combining three or more isocyanurate mononuclears with each other) etc.).

[0052] The proportion of isocyanurate mononuclear particles relative to the total amount of polyisocyanurate in pentamethylene diisocyanate is, for example, 20% by weight or more, preferably 28% by weight or more, for example, 60% by weight or less, preferably 55% by weight or less.

[0053] When the content of isocyanurate mononuclear bodies is within the above range, a polyurethane resin with excellent quick-drying properties and weather resistance can be obtained.

[0054] Furthermore, from the viewpoint of improving quick-drying properties, the content of isocyanurate mononuclear particles is preferably 30% by weight or more, preferably 55% by weight or less, and more preferably 48% by weight or less, relative to the total amount of polyisocyanurate.

[0055] It should be noted that the proportion of isocyanurate mononuclear particles can be determined by gel permeation chromatography (GPC) according to the examples described later.

[0056] That is, in the chromatogram of polyisocyanurate by gel permeation chromatography, the area ratio of the peak with a molecular weight of 400 to 600 (converted from polystyrene) to the area of ​​all peaks (hereinafter referred to as the 3-molecule area ratio) is equivalent to the proportion of isocyanurate mononuclear particles to the total amount of polyisocyanurate.

[0057] It should be noted that, for the 3 molecular volume area ratio, the molecular weight distribution of polyisocyanurate can be determined by gel permeation chromatography (GPC) equipped with a differential refractive index detector (RID) according to the examples described later, and the ratio can be calculated in the form of peak area ratio in the obtained chromatogram.

[0058] HDI-based polyisocyanates, preferably polyisocyanates containing biuret, urea diketone, urea carbamate, isocyanurate and / or iminooxadiazine trione groups, have a viscosity of 100-3000 mPas at 25°C and an isocyanate group content of 18 to 24% by weight.

[0059] In a preferred embodiment, in the preparation of the polyisocyanate composition, pentamethylene diisocyanate-based polyisocyanate and hexamethylene diisocyanate-based polyisocyanate are stirred, for example, at a temperature of 40-80°C, until the composition is uniformly mixed.

[0060] In addition, the polyisocyanate composition does not contain solvent, but can be prepared as a diluted polyisocyanurate solution by dilution with an organic solvent as needed.

[0061] Examples of organic solvents include ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; nitriles such as acetonitrile; alkyl esters such as methyl acetate, ethyl acetate, butyl acetate, and isobutyl acetate; aliphatic hydrocarbons such as n-hexane, n-heptane, and octane; alicyclic hydrocarbons such as cyclohexane and methylcyclohexane; aromatic hydrocarbons such as toluene, xylene, and ethylbenzene; glycol ether esters such as methyl cellosol acetate and ethyl cellosol acetate; halogenated aliphatic hydrocarbons such as chloromethane, dichloromethane, chloroform, carbon tetrachloride, bromomethane, diiodomethane, and dichloroethane; and polar aprotic hydrocarbons such as N-methylpyrrolidone, dimethylformamide, N,N'-dimethylacetamide, dimethyl sulfoxide, and hexamethylphosphoramide.

[0062] In addition, examples of organic solvents include non-polar solvents (non-polar organic solvents).

[0063] The above-mentioned organic solvents can be used alone or in combination of two or more.

[0064] Polyisocyanurate can be diluted by mixing it with the aforementioned organic solvent in any proportion. This yields a diluted solution of polyisocyanurate. It should be noted that, when preparing the diluted solution of polyisocyanurate, the organic solvent can be pre-mixed with the isocyanurate oligomer of pentamethylene diisocyanate, or an organic solvent can be separately mixed with the polyisocyanurate.

[0065] When preparing a diluent for polyisocyanurate, the concentration of polyisocyanurate relative to the total amount of the diluent is, for example, 20% by weight or more, preferably 30% by weight or more, for example, 95% by weight or less, preferably 90% by weight or less.

[0066] Therefore, polyisocyanurates can be suitably used in the manufacture of polyurethane resins. It should be noted that, in the manufacture of polyurethane resins, etc., as described below, polyisocyanurates can be mixed with other polyisocyanate monomers and / or derivatives.

[0067] Other polyisocyanates include, for example, alicyclic polyisocyanates, aromatic polyisocyanates, and aromatic aliphatic polyisocyanates, which are known or commonly used polyisocyanates.

[0068] Polyurethane resin can be obtained by reacting a polyisocyanate component containing the above-mentioned polyisocyanurate with a component containing a compound containing an active hydrogen group.

[0069] The polyisocyanate composition comprises the above-mentioned polyisocyanurate and, as needed, monomers and / or derivatives of the above-mentioned other polyisocyanates.

[0070] The technical solution provided by this invention has the following beneficial effects:

[0071] The purpose of this invention is to provide a polyisocyanate composition of a polyurethane resin that exhibits excellent quick-drying properties, improved solvent-resistant wiping performance, and good compatibility. Based on surprising observations, a solvent-free polyisocyanate composition of low-viscosity HDI polyisocyanate and low-monomer-weight polyisocyanurate based on pentamethylene diisocyanate can improve the viscosity of the polyisocyanate composition, resulting in more balanced and superior solvent-resistant wiping and drying performance, while also enhancing compatibility. Detailed Implementation

[0072] To better understand the technical solution of the present invention, the following embodiments further illustrate the content of the present invention, but the content of the present invention is not limited to the following embodiments.

[0073] The raw materials used in the following embodiments and comparative examples of this invention and their sources are as follows:

[0074] Pentamethylene diisocyanate (PDI), Wanhua Chemical Group Co., Ltd.

[0075] Hexamethylene diisocyanate polyisocyanurate trimer (HT-200) (NCO = 20.9 wt%, viscosity 3000 cp, 25°C) Wanhua Chemical Group Co., Ltd.; Unless otherwise specified, all contents in this invention are by weight.

[0076] The relevant test methods in the following embodiments and comparative examples of this invention are as follows:

[0077] (1) The NCO content test shall be performed in accordance with standard GB / T 12009.4;

[0078] (2) Viscosity testing shall be performed according to the dynamic viscosity at 25°C using a slab viscometer (Brookfield DT-2);

[0079] (3) The present invention is based on the method of GB / T18583-2008, and uses gas chromatography to determine the content of residual monomers in the reaction system;

[0080] (4) GPC determination method.

[0081] Table 1 GPC Test Conditions

[0082]

[0083]

[0084] Example

[0085] Polyisocyanate 1 (based on PDI)

[0086] Under a nitrogen atmosphere, 100 parts by weight of glutaraldehyde diisocyanate and 0.01 parts by weight of triethylamine were added to a reactor equipped with a thermometer, stirrer, nitrogen inlet pipe, and condenser. The mixture was stirred at 30°C for 60 minutes, then heated to 60°C. Next, 0.20 parts by weight (based on 100% effective component (catalyst)) of a 10% ethyl acetate solution of benzyltrimethylvalerate quaternary ammonium salt was added to the reactant solution to initiate the reaction. Then, 0.33 parts by weight (based on 100% effective component (catalyst)) of a 10% ethyl acetate solution of benzyltrimethylvalerate quaternary ammonium salt was added to the reaction mixture. The reaction was stopped 350 minutes after the start of the reaction, yielding a reaction mixture. The highest temperature reached during the reaction was 68°C. The isocyanate group concentration in the reactant solution was 54.5% by weight, and the isocyanate group concentration in the reaction mixture was 39.1% by weight. The resulting reaction mixture was then passed through a thin-film distillation apparatus (temperature 160°C, vacuum 50 Pa) to remove unreacted pentamethylene diisocyanate, yielding polyisocyanurate, an isocyanurate oligomer containing pentamethylene diisocyanate. It should be noted that the distillation yield of polyisocyanurate was 49.5% by weight. The conversion rate of isocyanate groups in this reaction (isocyanurate conversion) was 28.4% by weight. The viscosity (100% by weight) of polyisocyanurate at 25°C was 10725 mPa·s. Furthermore, the isocyanate group concentration (100% by weight) of polyisocyanurate was 22.9% by weight, the mononuclear content was 42.9% by weight, and the urea-formate signal and isocyanurate signal... 13 The C-NMR integral ratio (total urethane / 2: isocyanurate / 3 = 0) indicates that the free PDI monomer content is 0.06%.

[0087] Polyisocyanate 2: Contains isocyanurate and urethane groups (based on HDI) Wannate HT-200

[0088] NCO content: 20.9%

[0089] Solid content: 100%

[0090] Viscosity: 3000 mPa·s, 25℃

[0091] Polyisocyanate 3: Contains isocyanurate and diurea (HDI-based) Wannate HT-500

[0092] NCO: 23%

[0093] Solid content: 100%

[0094] Viscosity: 650 mPa·s, 25℃

[0095] Polyisocyanate 4: Contains isocyanurate and iminooxadiazine dione groups (based on HDI) Wannate HT-400

[0096] NCO: 22.1%

[0097] Solid content: 100%

[0098] Viscosity: 150 mPa·s, 25℃

[0099] Polyisocyanate 5: Contains a biuret group (HDI-based) Wannate HB-200

[0100] NCO: 23%

[0101] Solid content: 100%

[0102] Viscosity: 2500 mPa·s, 25℃

[0103] Examples 1-4

[0104] At room temperature, pentamethylene diisocyanate-based polyisocyanate and hexamethylene diisocyanate-based polyisocyanate were added to a reactor under N2 atmosphere, heated to 50°C and stirred until the composition was homogeneous.

[0105] The following table shows the composition (parts by weight) and characteristic data of the polyisocyanates A1 to A4 prepared according to this invention by this method.

[0106] Table 2. Polyisocyanate indices in the examples.

[0107]

[0108]

[0109] Examples of the preparation and application of polyisocyanate compositions

[0110] Application performance was tested in the AC6780 high hydroxyl system, comparing conventional HT-200 with PDI-based polyisocyanate 1.

[0111] Using the polyisocyanate components A1-A4 of Examples 1-4 above, and the isocyanate components B1-B2 of Comparative Examples 1-2 respectively, B1 is PDI-based polyisocyanate 1, and B2 is HT-200; hydroxyl-containing acrylic resin (produced by Tongde Resin, trade name: AC6780) is used as the polyol component. Paint preparation: The mixture is prepared according to an isocyanate group / hydroxyl molar ratio (NCO / OH) of 1.2:1, and diluted with a diluent (mass ratio of xylene: butyl acetate = 1:1) to a concentration of 50%. The mixture is then stirred at 23°C for 5 minutes and ultrasonically treated for 5 minutes to obtain a defoamed coating solution.

[0112] The paint formula is as follows:

[0113]

[0114] (1) Instrumental method for linear drying time test: The prepared paint is coated on a glass strip (150μm) and placed on a linear drying recorder for testing. The range is set to 24h.

[0115] (2) Hardness establishment test: The prepared paint was applied to a glass plate (100μm) and placed in an oven at 75℃. The pendulum hardness was tested after baking for 30min and 60min respectively.

[0116] (3) Solvent resistance: The prepared paint was applied to a film using a 100μm wire rod. After being dried at room temperature for 15 minutes, it was baked in an oven at 75℃ for 3 hours. After being removed and left at room temperature overnight, the solvent resistance (butanone) was tested.

[0117] (4) Compatibility test: The polyisocyanate component is mixed with butyl acetate and ethanol in a mass ratio of 3:3:4. The appearance is observed. Clear indicates good compatibility, while turbidity indicates poor compatibility.

[0118] (1) Linear drying performance test

[0119] Temperature: 24.2~24.6℃; Humidity: 37~42%RH

[0120] Table 3 Drying test results

[0121] Test Project A1 A2 A3 A4 B1 B2 2 stages / min 219 226 235 215 204 249 4 stages / min 380 405 419 425 360 436

[0122] (2) Pendulum stiffness test

[0123] Table 4. Hardness test results

[0124]

[0125]

[0126] (3) Solvent resistance (butanone) test

[0127] Table 5 Solvent resistance (methyl ethyl ketone) test results

[0128] Number of wipes A1 A2 A3 A4 B1 B2 75℃, 3 hours, room temperature, 1 day 185 167 150 134 195 90

[0129] (4) Compatibility test

[0130] Table 6 Compatibility Test Results

[0131] A1 A2 A3 A4 B1 B2 state clarify clarify clarify clarify turbid clarify

[0132] As can be seen from the examples and comparative examples, the present invention solves the problem of excessive viscosity of PDI polyisocyanurate and provides a polyisocyanate with excellent quick-drying properties, improved solvent resistance and compatibility.

[0133] It should be noted that although the invention has been described by way of illustrative embodiments, these are merely examples and should not be construed as limiting. Variations of the invention that will be apparent to those skilled in the art are also included within the scope of the appended claims.

Claims

1. A polyisocyanate composition comprising a mixture of the following components: ≥50% by weight of at least one polyisocyanate based on pentamethylene diisocyanate and ≤50% by weight of at least one polyisocyanate based on hexamethylene diisocyanate and / or at least one polyisocyanate based on pentamethylene diisocyanate and hexamethylene diisocyanate, wherein the polyisocyanate composition has a residual monomer content of less than 0.1% by weight of monomeric diisocyanate based on the total weight of the polyisocyanate composition.

2. The polyisocyanate composition according to claim 1, characterized in that... The mixture comprises at least 70% by weight, preferably ≥80% by weight, of the at least one pentamethylene diisocyanate-based polyisocyanate based on the total weight of the mixture, with the balance consisting of the at least one hexamethylene diisocyanate-based polyisocyanate and / or the at least one pentamethylene diisocyanate-based polyisocyanate and hexamethylene diisocyanate-based polyisocyanate.

3. The polyisocyanate composition according to claim 1 or 2, characterized in that... The mixture contains ≥2% by weight, preferably ≥5% by weight, particularly preferably ≥10% by weight, and very particularly preferably ≥20% by weight of the at least one polyisocyanate based on hexamethylene diisocyanate and / or the at least one polyisocyanate based on pentamethylene diisocyanate and hexamethylene diisocyanate, based on the total weight of the mixture.

4. The polyisocyanate composition according to any one of claims 1-3, characterized in that... Polyisocyanates based on pentamethylene diisocyanate and hexamethylene diisocyanate are formed from at least hexamethylene diisocyanate to a degree of ≥60% by weight, preferably ≥70% by weight.

5. The polyisocyanate composition according to any one of claims 1-4, characterized in that... The polyisocyanate composition consists of the mixture to a degree of ≥70% by weight, preferably ≥80% by weight, particularly preferably 100% by weight.

6. A method for preparing the polyisocyanate composition according to any one of claims 1-5, the method comprising: The at least one pentamethylene diisocyanate-based polyisocyanate is mixed with the at least one hexamethylene diisocyanate-based polyisocyanate and / or at least one polyisocyanate based on pentamethylene diisocyanate and hexamethylene diisocyanate, and one or more adjuvants and additives may be added before, during and / or after this process.

7. The method of claim 6, wherein the at least one polyisocyanate based on pentamethylene diisocyanate preferably isocyanurate oligomer of pentamethylene diisocyanate and unavoidably contained byproducts constitutes a polyisocyanate.

8. Use of the polyisocyanate composition according to any one of claims 1 to 5 or the polyisocyanate composition prepared by the preparation method according to claim 6 or 7 as a crosslinking agent in a coating composition.

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