An isocyanate self-polymerization catalyst and a preparation method thereof, and a polyisocyanate composition and a preparation method thereof

Abstract

The present invention relates to an isocyanate self-polymerization catalyst and a preparation method thereof and a polyisocyanate composition and a preparation method thereof. The catalyst has a general structural formula as shown in the following formula I. The present invention realizes the delocalization of positive charge in the dinitrogen atom region through structural design, thereby achieving the purpose of improving catalyst activity and reducing the amount of catalyst used in the synthesis of polyisocyanates. The method for preparing a polyisocyanate composition using the catalyst has the advantages of low purity requirements for raw material polyisocyanates and low amount of auxiliary agents, and the isocyanate composition prepared thereby has the advantages of low chroma and good stability.

Description

Technical Field

[0001] The present invention relates to the field of polyisocyanate preparation, and in particular to an isocyanate self-polymerization catalyst for preparing a polyisocyanate composition, a preparation method of the catalyst, and a polyisocyanate prepared by using the catalyst and a preparation method thereof. Background Art

[0002] Due to the low vapor pressure of aliphatic diisocyanates, their application is greatly limited. Generally, the most widely used form is to self-polymerize them into polyisocyanate compositions. Compared with diisocyanates, polyisocyanate compositions have higher functionality and better weather resistance.

[0003] The self-polymerization of aliphatic diisocyanates can only be achieved under mild conditions in the presence of a catalyst. However, compared with aromatic diisocyanates, their reaction activity is low, resulting in a higher catalyst concentration required for the reaction. The amount of catalyst and other auxiliary agents introduced is high, and the residue in the polyisocyanate composition will affect its own stability.

[0004] US673062, US6800714, and US7001973 all use quaternary ammonium salt cations in which R1 contains a benzene derivative structure, R2 and R3 are alkyl or substituted alkyl or cycloalkyl, and R4 is alkyl or cycloalkyl or alkoxy, which can efficiently synthesize products. However, it should be pointed out that the color number control still cannot meet the requirements of industrial production for low color number polyisocyanate compounds.

[0005] US5489663 also uses a variety of cation designs to achieve ideal chromaticity control effects, but its catalyst design results in low reaction activity and requires higher reaction temperature control. When the temperature control is low, the reaction time is extended exponentially.

[0006] In addition, the use of the above existing catalysts requires the use of polyisocyanate raw materials with relatively high purity, such as reducing the hydrolysis chlorine of the raw materials through refining. Summary of the invention

[0007] In view of the above problems existing in the prior art, one of the objects of the present invention is to provide an isocyanate self-polymerization catalyst, which realizes the delocalization of positive charge in the dinitrogen atom region through a P-π conjugated structure, and the synergy of quaternary ammonium and tertiary amine improves the tolerance of the catalyst to impurities in diisocyanate, and the hydroxyl group on the β-position of the quaternary ammonium further enhances the catalytic activity.

[0008] Another object of the present invention is to provide a method for preparing the above-mentioned isocyanate self-polymerization catalyst.

[0009] Another object of the present invention is to provide a polyisocyanate composition prepared using the above catalyst and a preparation method thereof, wherein the method has the advantages of low purity requirements for the raw material polyisocyanate and small amount of auxiliary agent, and the isocyanate composition prepared thereby has the advantages of low chroma and good stability.

[0010] To achieve one aspect of the above object, the present invention adopts the following technical solution:

[0011] The present invention provides an isocyanate self-polymerization catalyst, wherein the catalyst has a general structural formula as shown in the following formula I:

[0012]

[0013] In the formula, R1 and R2 are independently selected from C1-C8 (such as C2, C3, C4, C5, C6 or C7) straight chain alkyl, C3-C15 (such as C5, C8, C10, C12 or C14) branched alkyl, C3-C8 (such as C4 or C6) cycloalkyl;

[0014] R3 is selected from hydrogen, phenyl, C7-C12 substituted phenyl (such as p-methylphenyl, m-chlorobenzoic acid), C4-C10 aromatic heterocyclic group containing heteroatoms such as N, S, O (such as pyrrolyl, pyridyl, thienyl), C1-C15 (such as C3, C5, C8, C10 or C12) straight chain alkyl, C3-C15 (such as C5, C8, C10 or C12) branched alkyl.

[0015] The present invention starts from the structural design of the isocyanate self-polymerization catalyst, and delocalizes the positive charge in the two nitrogen atom regions through the P-π conjugated structure. Compared with the traditional quaternary ammonium catalyst containing one nitrogen cation active center, the catalyst capable of positive charge delocalization has a larger contact range with the isocyanate group and higher reaction activity;

[0016]

[0017] At the same time, the synergy of quaternary ammonium and tertiary amine can improve the catalyst's tolerance to impurities in diisocyanate (such as hydrolyzed chlorine), so that it still has good activity in the process of catalyzing diisocyanate with lower purity;

[0018]

[0019] In addition, the hydroxyl group at the β-position of the quaternary ammonium forms carbamate with isocyanate, and the resulting active hydrogen coordinates with the isocyanate group, further enhancing the catalytic activity.

[0020]

[0021] In another aspect to achieve the above object, the present invention also provides a method for preparing the above isocyanate self-polymerization catalyst, comprising the following steps:

[0022] (1) 3-bromopropylamine is reacted with an epoxy compound to obtain an intermediate product a;

[0023] (2) dissolving the intermediate product a obtained in step (1) in dichloromethane, adding triethylamine as an acid binding agent, and then adding a substituted amine to react, filtering, and removing the solvent to obtain an intermediate product b;

[0024] (3) reacting the intermediate product b obtained in step (2) with triethyl orthoformate to obtain an intermediate product c;

[0025] (4) adding carboxylic acid to the intermediate product c obtained in step (3) to carry out a reaction to obtain an isocyanate self-polymerization catalyst represented by formula I.

[0026] In the present invention, the epoxy compound in step (1), the substituted amine in step (2), and the carboxylic acid in step (4) have structures shown in Formula II, Formula III, and Formula IV, respectively.

[0027] R1-NH2(Ⅲ),

[0028] wherein the substituents R1, R2, and R3 are the same as those in formula I, i.e., R1 and R2 are independently selected from a C1-C8 (e.g., C2, C3, C4, C5, C6, or C7) straight-chain alkyl group, a C3-C15 (e.g., C5, C8, C10, C12, or C14) branched-chain alkyl group, or a C3-C8 (e.g., C4 or C6) cycloalkyl group;

[0029] R3 is selected from hydrogen, phenyl, C7-C12 substituted phenyl (such as p-methylphenyl, m-chlorobenzoic acid), C4-C10 aromatic heterocyclic group containing heteroatoms such as N, S, O (such as pyrrolyl, pyridyl, thienyl), C1-C15 (such as C3, C5, C8, C10 or C12) straight chain alkyl, C3-C15 (such as C5, C8, C10 or C12) branched alkyl.

[0030] In the method for preparing the isocyanate self-polymerization catalyst of the present invention, the reaction formulas of steps (1) to (4) can be expressed as follows:

[0031]

[0032]

[0033] In step (1) of the present invention, the molar ratio of the epoxy compound to 3-bromopropylamine is 1-1.1:1, preferably 1-1.04:1.

[0034] In step (1) of the present invention, the reaction pressure is 0.05-3MpaG, preferably 0.1-1MpaG; the temperature is 0-30°C, preferably 0-20°C; the time is 1.5-10h, preferably 2-8h;

[0035] Preferably, the reaction is carried out in stages, specifically, first reacting at 0-5°C for 1-5h, then heating to 10-20°C for 1-3h;

[0036] In step (1) of the present invention, the epoxy compound is added continuously, preferably dropwise;

[0037] Preferably, the epoxy compound addition time is 10-60 min, and the addition time is not included in the above reaction time.

[0038] In step (2) of the present invention, the concentration of the intermediate product a dissolved in dichloromethane is 10-80wt%, preferably 20-60wt%.

[0039] In step (2) of the present invention, the molar ratio of the amount of triethylamine used to the amount of 3-bromopropylamine in step (1) is 1-1.03:1, preferably 1:1.

[0040] In step (2) of the present invention, the molar ratio of the amount of the substituted amine to the amount of 3-bromopropylamine in step (1) is 1-1.03:1, preferably 1:1.

[0041] In step (2) of the present invention, the reaction pressure is 0.1-5MpaG, preferably 0.1-4MpaG; the temperature is 10-50°C, preferably 10-40°C; and the time is 1-10h, preferably 1-5h.

[0042] In step (2) of the present invention, the substituted amine is added continuously, preferably dropwise;

[0043] Preferably, the addition time of the substituted amine is 20-80 min, and the addition time is not included in the above reaction time.

[0044] In step (2) of the present invention, after the reaction is completed, post-treatment processes such as filtration and solvent removal are also included, which are conventional operations in the field and are not specifically required by the present invention.

[0045] In step (3) of the present invention, the molar ratio of the amount of triethyl orthoformate used to the 3-bromopropylamine in step (1) is 1-1.3:1.

[0046] In step (3) of the present invention, the reaction temperature is 100-150°C, preferably 100-130°C; the reaction time is 1-5h, preferably 1-4h.

[0047] In step (4) of the present invention, the molar ratio of the amount of the carboxylic acid to the amount of 3-bromopropylamine in step (1) is 1-1.2:1.

[0048] In step (4) of the present invention, the reaction temperature is 10-50°C, preferably 10-30°C; and the reaction time is 1-10h, preferably 1-3h.

[0049] In order to achieve the above-mentioned object, the present invention also provides a polyisocyanate composition prepared by using the isocyanate self-polymerization catalyst shown in the above formula I, using the following technical scheme:

[0050] The method for preparing the polyisocyanate composition of the present invention comprises the following steps: the composition is prepared by oligomerization of at least one isocyanate monomer having an NCO functionality > 1 in the presence of an isocyanate self-polymerization catalyst represented by the above formula I.

[0051] The preparation method of the composition of the present invention, the isocyanate monomer is selected from aliphatic diisocyanates, preferably hexamethylene diisocyanate (HDI), pentamethylene diisocyanate (PDI), 2-methylpentane-1,5-diisocyanate, 2,4,4-trimethyl-1,6-hexane diisocyanate, 2,2,4-trimethyl-1,6-hexane diisocyanate, 4-isocyanatomethyl-1,8-octane diisocyanate, 3(4)-isocyanatomethyl-1-methylcyclohexyl isocyanate (IMCI), isophorone diisocyanate (IPDI), 1,3- and 1,4-bis(isocyanatomethyl)benzene (XDI), and one or more of 1,3- and 1,4-bis(isocyanatomethyl)cyclohexane (H6XDI);

[0052] The diisocyanate suitable for the preparation method of the composition of the present invention may have a hydrolyzed chlorine range of 5-500 ppm, such as 5, 50, 100, 150, 200, 250, 300, 350, 400, 450 ppm, etc. In order to better promote the target reaction, according to the preparation method of the composition of the present invention, preferably, during the preparation process, the isocyanate self-polymerization catalyst represented by formula I is added in the form of an alcohol solution, preferably, the mass concentration of the catalyst in the alcohol is 1-50%, such as 2%, 5%, 10%, 15%, 20%, 30% or 40%;

[0053] The catalyst is used in an amount of 10-50000 ppm, preferably 20-50000 ppm, such as 100 ppm, 1000 ppm, 5000 ppm, 10000 ppm or 15000 ppm, based on the mass of the isocyanate monomer;

[0054] Preferably, the alcohol solvent is a monohydric alcohol and / or a dihydric alcohol; wherein the monohydric alcohol is preferably selected from aliphatic, alicyclic, aromatic aliphatic or aromatic alcohols or phenols of C1-C10, and the monohydric alcohol is preferably in the form of a straight chain, branched chain or cyclic alcohol or phenol; the dihydric alcohol is not limited to the following, for example, ethylene glycol, 1,3-propylene glycol, 1,2-propylene glycol, 1,3-butylene glycol, 1,4-butylene glycol, 2,3-butylene glycol, 1,5- Pentanediol, 1,2-pentanediol, 1,3-pentanediol, 1,4-pentanediol, neopentyl glycol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, diethylene glycol, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, 2-methyl-1,3-propanediol, 3-methyl-1,5-pentanediol, 2-methyl-1,8-octanediol and 2,2-diethyl-1,3-propanediol.

[0055] According to the preparation method of the composition of the present invention, preferably, the oligomerization reaction is carried out at a temperature of 20°C-100°C, preferably 40-80°C, such as 30, 50 or 70°C.

[0056] According to the preparation method of the composition of the present invention, preferably, the oligomerization reaction end point is 10-80wt% of NCO conversion rate, preferably 20-70wt%, such as 40wt% or 50wt% of isocyanate monomer conversion after termination; further preferably, the oligomerization reaction is terminated by deactivating the catalyst, further preferably, adding acid or acid derivatives such as benzoyl chloride, adding acid esters of acids containing phosphorus or sulfur, these acids themselves, particularly preferably thermal decomposition deactivation. In the present invention, after the reaction is terminated, the unreacted monomeric organic isocyanate can be separated from the reaction mixture for recycling.

[0057] According to the preparation method of the composition of the present invention, preferably, the method of evaporating the filtered reaction solution to remove unreacted monomers is any one of thin film evaporation, falling film evaporation, short path evaporation and vacuum distillation.

[0058] Furthermore, the method of evaporating the reaction solution to remove the unreacted monomers is a two-stage thin film evaporation. For example, the conditions for the first stage thin film evaporation are: a temperature of 100-200°C, preferably 120-170°C, and a thin film evaporation pressure of 5-300Pa, preferably 10-200Pa; the conditions for the second stage thin film evaporation are: a temperature of 110-200°C, preferably 130-170°C, and a thin film evaporation pressure of 5-200Pa, preferably 10-100Pa.

[0059] The polyisocyanate composition prepared by the method using the isocyanate self-polymerization catalyst of the present invention has the advantages of low chroma, good stability and the like.

[0060] Compared with the prior art, the technical solution of the present invention has the following beneficial effects:

[0061] The present invention starts from the design of the catalyst and introduces a -NC=N- structure to delocalize the cation center, thereby expanding the contact range between the catalyst and the isocyanate, and improving the reaction activity; at the same time, the synergy of the quaternary ammonium and the tertiary amine can improve the tolerance of the catalyst to impurities (such as hydrolyzed chlorine) in the diisocyanate, so that the catalyst still has good activity in the process of catalyzing diisocyanates with lower purity; at the same time, the hydroxyl group at the β-position of the quaternary ammonium is introduced to form carbamate with the isocyanate, and the resulting active hydrogen is coordinated with the isocyanate, further improving the catalytic activity.

[0062] The catalyst is used to prepare a polyisocyanate composition. The catalyst has a high tolerance to impurities (such as hydrolyzed chlorine) in diisocyanate. Even if diisocyanate of lower purity is used as a raw material, the synthesis process still has good activity, avoiding the stringent requirements for raw material separation and purification, and further reducing energy consumption and material consumption. The polyisocyanate composition prepared by the catalyst has the advantages of low chroma, good stability, etc. DETAILED DESCRIPTION

[0063] The present invention is further described below in conjunction with examples. It should be noted that the examples do not limit the scope of protection claimed for the present invention.

[0064] All percentages involved in the present invention are by mass unless otherwise specified.

[0065] The present invention determines the NCO content according to the method of GB / T 12009.4-1989;

[0066] The dynamic viscosity of the present invention is obtained using a BrookField DV-I Prime viscometer with an S21 rotor at 25°C;

[0067] The viscosity growth rate of the polyisocyanate composition in the present invention = (viscosity of the composition before storage - viscosity of the composition after storage) / viscosity of the composition before storage * 100%;

[0068] The present invention measures the chromaticity of the polyisocyanate composition in a 50 mm disposable rectangular cuvette using LICO 400 of HACH Lange Company based on the method of GB / T 3143-1982;

[0069] The main raw materials used in the examples of the present invention are from the following sources. Other raw materials are common commercially available unless otherwise specified:

[0070] Hexamethylene diisocyanate (HDI), Wanhua Chemical Group Co., Ltd.; isophorone diisocyanate (IPDI), Wanhua Chemical Group Co., Ltd.; pentamethylene diisocyanate (PDI), Wanhua Chemical Group Co., Ltd.; tetramethylammonium hydroxide solution (25%, methanol solution), Sigma-Aldrich; decanoic acid, purity ≥99%, Sigma-Aldrich;

[0071] n-Butanol, purity ≥99%, Inokane;

[0072] 1,3-Butanediol, purity ≥99%, TCI;

[0073] 85% phosphoric acid, purity ≥85%, Inokane;

[0074] Dibutyl phosphate, purity ≥97%, Inokane;

[0075] Benzoic acid, purity ≥99.5%, Inokane;

[0076] Benzoyl chloride, purity ≥98%, TCI;

[0077] 3-Bromopropylamine, purity ≥99%, Inokane;

[0078] Propylene oxide, Wanhua Chemical Group Co., Ltd.;

[0079] Ethylene oxide, Wanhua Chemical Group Co., Ltd.;

[0080] Methylamine, purity ≥98%, Inokane;

[0081] Ethylamine, purity ≥70%, Acros;

[0082] Cyclopentylamine, purity ≥98%, Inokane;

[0083] Triethylamine, purity ≥99.5%, Inokane;

[0084] Triethyl orthoformate, purity ≥99%, Inokite;

[0085] 2-Ethylhexanoic acid, purity ≥99%, Inokane;

[0086] Acetic acid, purity ≥99%, Inokane;

[0087] Dabco TMR-3, Evonik Industries.

[0088] Main equipment in the embodiments of the present invention and the comparative examples:

[0089] Two-stage thin film evaporator, first-stage evaporator area 0.1m 2 , secondary evaporator area 0.05m 2 ;

[0090] Reactor, volume 5L, anchor type stirring paddle, rotating diameter 100mm.

[0091] Example 1

[0092] Preparation of isocyanate self-polymerization catalyst Ia, the steps are:

[0093] (1) In an ice-water bath at 0°C and 0.9 MPa, 10 g (0.227 mol) of ethylene oxide was gradually added to 30 g (0.219 mol) of 3-bromopropylamine for 40 min. After the addition was completed, the reaction was continued at 0°C and 0.9 MPa for 2 h, and then the temperature was raised to 20°C and the reaction was continued for 1 h to obtain an intermediate product a;

[0094] Characterization: HRMS (ESI+): [M+H] + Calcd for C5H 13 BrNO + 182.0175,Found:182.0174

[0095] (2) Add dichloromethane to the intermediate product a of step (1) to prepare a solution with a concentration of 20 wt%, then add 23 g (0.227 mol) of triethylamine, gradually add 7 g (0.225 mol) of methylamine to the above solution at 30° C. and 4 MPaG, the addition time is 30 min, and the reaction is continued for 1 h, the residue is removed by filtration, and the solvent is removed to obtain the intermediate product b;

[0096] Characterization: HRMS (ESI+): [M+H] + Calcd for C6H 17 N2O + 133.1335,Found:133.1336

[0097] (3) adding 35.7 g (0.241 mol) of triethyl orthoformate to the intermediate product b of step (2), and reacting at 105° C. for 4.5 h to obtain an intermediate product c;

[0098] Characterization: HRMS(ESI+): Calcd for C7H 15 N2O + 143.1179,Found:143.1179

[0099] (4) Add 13.4 g (0.223 mol) of acetic acid to the intermediate product c of step (3), and react at 30° C. for 1 h to obtain catalyst Ia.

[0100] Characterization: HRMS(ESI+): Calcd for C7H 15N2O + 143.1179,Found:143.1180

[0101] HRMS(ESI-):Calcd for C2H3O2 - 59.0139,Found:59.0138

[0102] 13 C NMR (CDCl3, 100MHz): δ176.4,151.3,59.3,58.5,41.1,40.1,38.8,23.1,19.5

[0103] The structure of catalyst Ia is as follows:

[0104]

[0105] Example 2

[0106] Preparation of isocyanate self-polymerization catalyst Ib, the steps are:

[0107] (1) In an ice-water bath at 0°C and 0.5 MPa, 13.7 g (0.236 mol) of propylene oxide was gradually added to 30 g (0.219 mol) of 3-bromopropylamine for 30 min. After the addition was completed, the reaction was continued at 0°C and 0.5 MPa for 1 h, and then the temperature was raised to 10°C and the reaction was continued for 3 h to obtain an intermediate product a;

[0108] Characterization: HRMS (ESI+): [M+H] + Calcd for C6H 15 BrNO + 196.0332,Found:196.0333

[0109] (2) Add dichloromethane to the intermediate product a of step (1) to prepare a solution with a concentration of 50 wt%, then add 22.2 g (0.220 mol) of triethylamine, and gradually add 9.9 g (0.225 mol) of ethylamine to the above solution at 30° C. and 2 MPaG for 30 min, then continue the reaction for 2 h, filter to remove the residue, remove the solvent, and obtain the intermediate product b;

[0110] Characterization: HRMS (ESI+): [M+H] + Calcd for C8H 21 N2O + 161.1648,Found:161.1646

[0111] (3) adding 38.9 g (0.263 mol) of triethyl orthoformate to the intermediate product b of step (2), and reacting at 145° C. for 1 h to obtain an intermediate product c;

[0112] Characterization: HRMS(ESI+): Calcd for C9H 19 N2O + 171.1492,Found:171.1493

[0113] (4) Add 41.5 g (0.223 mol) of decanoic acid to the intermediate product c of step (3), and react at 20° C. for 2 h to obtain catalyst Ib.

[0114] Characterization: HRMS(ESI+): Calcd for C9H 19 N2O + 171.1492,Found:171.1492HRMS(ESI-):Calcd for C8H 15 O2 - 143.1078,Found:143.1076

[0115] 13 C NMR (CDCl3, 100MHz): δ179.6,153.1,63.8,63.5,47.1,44.2,39.1,31.9,30.5,29.6,25.5,23.1,22.8,19.5,14.3,12.3,6.5;

[0116] The structure of catalyst Ib is as follows:

[0117]

[0118] Example 3

[0119] Preparation of isocyanate self-polymerization catalyst Ic, the steps are:

[0120] (1) In an ice-water bath at 0°C and 0.3 MPa, 13.7 g (0.236 mol) of propylene oxide was gradually added to 30 g (0.219 mol) of 3-bromopropylamine for 20 min. After the addition was completed, the reaction was continued at 0°C and 0.3 MPa for 5 h, and then the temperature was raised to 5°C and the reaction was continued for 1 h to obtain an intermediate product a;

[0121] (2) adding dichloromethane to the intermediate product a of step (1) to prepare a solution with a concentration of 75 wt%, then adding 24 g (0.237 mol) of triethylamine, and gradually adding 14.0 g (0.237 mol) of isopropylamine to the above solution at 40° C. and 0.5 MPaG for 30 min, and then continuing the reaction for 3 h, filtering to remove the residue, and removing the solvent to obtain the intermediate product b;

[0122] Characterization: HRMS (ESI+): [M+H] + Calcd for C9H 23 N2O + 175.1805,Found:175.1804

[0123] (3) adding 42 g (0.284 mol) of triethyl orthoformate to the intermediate product b of step (2), and reacting at 125° C. for 2.5 h to obtain an intermediate product c;

[0124] Characterization: HRMS(ESI+): Calcd for C 10 H 21 N2O + 185.1648,Found:185.1646

[0125] (4) Add 37.8 g (0.262 mol) of isooctanoic acid to the intermediate product c of step (3), and react at 10° C. for 3 h to obtain catalyst Ic.

[0126] Characterization: HRMS(ESI+): Calcd for C 10 H 21 N2O + 185.1648,Found:185.1649HRMS(ESI-):Calcd for C8H 15 O2 - 143.1078,Found:143.1077

[0127] 13 C NMR (CDCl3, 100MHz): δ177.6,151.5,63.1,63.1,62.3,47.5,45.3,44.1,31.7,29.3,25.1,23.2,22.6,21.5,21.5,19.7,14.6,11.8;

[0128] The structure of catalyst Ic is as follows:

[0129]

[0130] Example 4

[0131] Preparation of isocyanate self-polymerization catalyst Id, the steps are:

[0132] (1) In an ice-water bath at 0°C and 0.85 MPa, 10 g (0.227 mol) of ethylene oxide was gradually added to 30 g (0.219 mol) of 3-bromopropylamine for 40 min. After the addition was completed, the reaction was continued at 0°C and 0.85 MPa for 3 h, and then the temperature was raised to 15°C and the reaction was continued for 2 h to obtain an intermediate product a;

[0133] (2) Add dichloromethane to the intermediate product a of step (1) to prepare a solution with a concentration of 50 wt%, then add 23 g (0.227 mol) of triethylamine, and gradually add 19.3 g (0.227 mol) of cyclopentylamine to the above solution at 50° C. and 0.1 MPaG. The addition time is 1 hour, and the reaction is continued for 5 hours. The residue is removed by filtration, and the solvent is removed to obtain the intermediate product b;

[0134] Characterization: HRMS (ESI+): [M+H] + Calcd for C 10 H 23 N2O + 187.1805,Found:187.1804

[0135] (3) adding 37.3 g (0.252 mol) of triethyl orthoformate to the intermediate product b of step (2), and reacting at 140° C. for 5 h to obtain an intermediate product c;

[0136] Characterization: HRMS(ESI+): Calcd for C 11 H 21 N2O + 197.1648,Found:197.1649

[0137] (4) Add 30.7 g (0.252 mol) of benzoic acid to the intermediate product c of step (3), and react at 20° C. for 1 h to obtain catalyst Id.

[0138] Characterization: HRMS(ESI+): Calcd for C 11 H 21 N2O + 197.1648,Found:197.1648HRMS(ESI-):Calcd for C7H5O2 - 121.0295,Found:121.0294

[0139] 13C NMR (CDCl3, 100 MHz): δ 179.1, 154.1, 136.8, 134.6, 129.7, 129.7, 128.2, 128.2, 62.5, 59.3, 58.1, 46.3, 44.1, 33.6, 33.6, 25.2, 25.2, 19.7; The structure of catalyst Id is as follows:

[0140]

[0141] Example 5

[0142] The isocyanate composition is prepared by:

[0143] Under nitrogen atmosphere, 3 kg of diisocyanate monomer HDI (15 ppm of hydrolyzed chlorine) was added to a 5 L reactor, and the system was heated to 45°C. Then 25 ppm of the isocyanate self-polymerization catalyst Ⅰ-a prepared in Example 1 (prepared as a 1.5 wt% n-butanol solution) was added to initiate the reaction; the NCO content of the reaction solution was measured to detect the reaction progress. When the reaction conversion rate reached 42%, 14 ppm of the terminator 85% phosphoric acid was added to terminate the reaction;

[0144] Then, a two-stage thin film evaporator is used to remove unreacted diisocyanate monomers to obtain a polyisocyanate composition.

[0145] The performance test results of the prepared isocyanate composition are shown in Table 2.

[0146] Example 6

[0147] The isocyanate composition is prepared by:

[0148] Under nitrogen atmosphere, 3 kg of diisocyanate monomer HDI (30 ppm of hydrolyzed chlorine) was added to a 5 L reactor, and the system was heated to 55°C. Then 50 ppm of isocyanate self-polymerization catalyst Ⅰ-b prepared in Example 2 (prepared as a 20 wt% n-butanol solution) was added to initiate the reaction; the NCO content of the reaction solution was measured to detect the reaction progress. When the reaction conversion rate reached 39%, 17 ppm of terminator 85% phosphoric acid was added to terminate the reaction;

[0149] Then, a two-stage thin film evaporator is used to remove unreacted diisocyanate monomers to obtain a polyisocyanate composition.

[0150] The performance test results of the prepared isocyanate composition are shown in Table 2.

[0151] Example 7

[0152] The isocyanate composition is prepared by:

[0153] Under nitrogen atmosphere, 3 kg of diisocyanate monomer HDI (hydrolyzed chlorine is 50 ppm) was added to a 5 L reactor, and the system was heated to 55°C. Then 100 ppm of the isocyanate self-polymerization catalyst Ⅰ-b prepared in Example 2 (prepared as a 20 wt% n-butanol solution) was added to initiate the reaction; the NCO content of the reaction solution was measured to detect the reaction progress, and when the reaction conversion rate reached 38.5%, 34 ppm of the terminator 85% phosphoric acid was added to terminate the reaction;

[0154] Then, a two-stage thin film evaporator is used to remove unreacted diisocyanate monomers to obtain a polyisocyanate composition.

[0155] The performance test results of the prepared isocyanate composition are shown in Table 2.

[0156] Example 8

[0157] The isocyanate composition is prepared by:

[0158] Under nitrogen atmosphere, 3 kg of diisocyanate monomer PDI (500 ppm of hydrolyzed chlorine) was added to a 5 L reactor, and the system was heated to 65°C. Then 400 ppm of the isocyanate self-polymerization catalyst I-c prepared in Example 3 (prepared as a 40 wt% n-butanol solution) was added to initiate the reaction; the NCO content of the reaction solution was measured to detect the reaction progress, and when the reaction conversion rate reached 30%, 300 ppm of the terminator dibutyl phosphate was added to terminate the reaction;

[0159] Then, a two-stage thin film evaporator is used to remove unreacted diisocyanate monomers to obtain a polyisocyanate composition.

[0160] The performance test results of the prepared isocyanate composition are shown in Table 2.

[0161] Example 9

[0162] The isocyanate composition is prepared by:

[0163] Under nitrogen atmosphere, 3 kg of diisocyanate monomer IPDI (200 ppm of hydrolyzed chlorine) was added to a 5 L reactor, and the system was heated to 75°C. Then 300 ppm of isocyanate self-polymerization catalyst I-d prepared in Example 4 (prepared as 2.5 wt% 1,3-butanediol solution) was added to initiate the reaction; the NCO content of the reaction solution was measured to detect the reaction progress. When the reaction conversion rate reached 25%, 175 ppm of terminator benzoyl chloride was added to terminate the reaction;

[0164] Then, a two-stage thin film evaporator is used to remove unreacted diisocyanate monomers to obtain a polyisocyanate composition.

[0165] The performance test results of the prepared isocyanate composition are shown in Table 2.

[0166] Comparative Example 1

[0167] Weigh 200g of tetramethylammonium hydroxide (25wt% methanol solution) into a 500mL flask, add 30.25g of capric acid (tetramethylammonium hydroxide / capric acid = 1 / 1.1 (molar ratio)) dropwise using a dropping funnel, stir at room temperature for 30min, and distill off methanol at 200Pa / 50℃ / 30min.

[0168] 312 g of n-butanol was added thereto to obtain 390 g of a 20 wt% n-butanol solution of tetramethylammonium decanoate;

[0169] Referring to the method of Example 6, the only difference is that the isocyanate self-polymerization catalyst I-b prepared in Example 2 is replaced by 1000 ppm tetramethylammonium decanoate catalyst, and other operations remain unchanged to obtain a polyisocyanate composition. The performance test results are shown in Table 2.

[0170] Comparative Example 2

[0171] Referring to the method of Example 7, the only difference is that the isocyanate self-polymerization catalyst I-b prepared in Example 2 is replaced by 3000 ppm of the tetramethylammonium decanoate catalyst prepared in Comparative Example 1, and other operations remain unchanged to obtain a polyisocyanate composition. The performance test results are shown in Table 2.

[0172] Comparative Example 3

[0173] Referring to the method of Example 8 (the hydrolysis chlorine of the diisocyanate monomer PDI is 500 ppm), the only difference is that the isocyanate self-polymerization catalyst I-c prepared in Example 3 is replaced by 10000 ppm of the tetramethylammonium decanoate catalyst prepared in Comparative Example 1, and other operations remain unchanged to obtain a polyisocyanate composition. The performance test results are shown in Table 2.

[0174] Comparative Example 4

[0175] Referring to the method of Example 6, the only difference is that the isocyanate self-polymerization catalyst I-b prepared in Example 2 is replaced by 800 ppm of Dabco TMR-2 catalyst, and other operations remain unchanged to obtain a polyisocyanate composition. The performance test results are shown in Table 2.

[0176] Table 1 Comparison of main reaction conditions of Examples 5-9 and Comparative Examples 1-4

[0177]

[0178] It can be seen from the preparation methods provided in the above embodiments and comparative examples that:

[0179] The isocyanate self-polymerization catalyst of the present invention has good catalytic activity and can maintain a low catalyst dosage even when the raw material impurity (hydrolyzed chlorine) content is high.

[0180] Table 2 Performance data of isocyanate compositions of Examples 5-9 and Comparative Examples 1-4

[0181]

[0182] The performance data of the isocyanate compositions prepared in the above examples and comparative examples show that:

[0183] The composition synthesized by using the isocyanate self-polymerization catalyst of the present invention has lower chroma and higher stability.

Claims

1. An isocyanate self-polymerization catalyst, characterized in that It has the general structural formula shown in the following formula I: In the formula, R1 and R2 are independently selected from C1-C8 straight chain alkyl, C3-C15 branched chain alkyl, C3-C8 cycloalkyl; R3 is selected from hydrogen, phenyl, C7-C12 substituted phenyl, C4-C10 aromatic heterocyclic group containing N, S, O heteroatoms, C1-C15 straight chain alkyl, C3-C15 branched alkyl.

2. The isocyanate self-polymerization catalyst according to claim 1, characterized in that The C7-C12 substituted phenyl group is selected from p-methylphenyl; the C4-C10 aromatic heterocyclic group containing N, S, and O heteroatoms is selected from pyrrolyl, pyridyl, and thienyl.

3. A method for preparing the isocyanate self-polymerization catalyst according to claim 1 or 2, characterized in that: The following steps are involved: (1) 3-bromopropylamine is reacted with an epoxy compound to obtain an intermediate product a; (2) dissolving the intermediate product a obtained in step (1) in dichloromethane, adding triethylamine as an acid binding agent, and then adding a substituted amine to react, filtering, and removing the solvent to obtain an intermediate product b; (3) reacting the intermediate product b obtained in step (2) with triethyl orthoformate to obtain an intermediate product c; (4) adding carboxylic acid to the intermediate product c obtained in step (3) to carry out a reaction to prepare an isocyanate self-polymerization catalyst represented by formula I; Specifically, the reaction formula of steps (1)-(4) is as follows: In the formula, substituents R1, R2 and R3 are the same as those in formula I.

4. The preparation method according to claim 3, characterized in that: In step (1), the molar ratio of the epoxy compound to 3-bromopropylamine is 1-1.1:1; In step (1), the reaction is carried out at a pressure of 0.05-3 MPaG, a temperature of 0-30° C., and a time of 1.5-10 h; In step (1), the epoxy compound is added in a continuous manner.

5. The preparation method according to claim 4, characterized in that: The molar ratio of the epoxy compound to 3-bromopropylamine is 1-1.04:

1.

6. The preparation method according to claim 4, characterized in that: In step (1), the reaction is carried out at a pressure of 0.1-1 MPaG, a temperature of 0-20° C., and a time of 2-8 h.

7. The preparation method according to claim 4, characterized in that: In step (1), the reaction is carried out in stages, specifically, first reacting at 0-5°C for 1-5h, and then heating to 10-20°C for 1-3h.

8. The preparation method according to claim 4, characterized in that: The epoxy compound addition time is 10-60 minutes.

9. The preparation method according to claim 4, wherein the epoxy compound is added dropwise.

10. The preparation method according to claim 3, characterized in that: In step (2), the concentration of the intermediate product a dissolved in dichloromethane is 10-80wt%; In step (2), the molar ratio of the amount of triethylamine used to the amount of 3-bromopropylamine in step (1) is 1-1.03:1; In step (2), the molar ratio of the amount of the substituted amine to the amount of 3-bromopropylamine in step (1) is 1-1.03:1; In step (2), the reaction is carried out at a pressure of 0.1-5 MPaG, a temperature of 10-50°C, and a time of 1-10 h; In step (2), the substituted amine is added in a continuous manner.

11. The preparation method according to claim 10, characterized in that: In step (2), the concentration of the intermediate product a dissolved in dichloromethane is 20-60wt%.

12. The preparation method according to claim 10, characterized in that: In step (2), the reaction is carried out under a pressure of 0.1-4 MPaG, a temperature of 10-40°C, and a time of 1-5 h.

13. The preparation method according to claim 10, characterized in that: The addition time of the substituted amine is 20-80 minutes.

14. The preparation method according to claim 10, characterized in that: The substituted amine is added dropwise.

15. The preparation method according to claim 3, characterized in that: In step (3), the molar ratio of the amount of triethyl orthoformate to the amount of 3-bromopropylamine in step (1) is 1-1.3:1; In step (3), the reaction temperature is 100-150° C. and the reaction time is 1-5 h; In step (4), the molar ratio of the amount of the carboxylic acid to the amount of 3-bromopropylamine in step (1) is 1-1.2:1; In step (4), the reaction temperature is 10-50°C and the reaction time is 1-10h.

16. The preparation method according to claim 15, characterized in that: In step (3), the reaction temperature is 100-130° C. and the reaction time is 1-4 h.

17. The preparation method according to claim 15, characterized in that: In step (4), the reaction temperature is 10-30°C and the reaction time is 1-3h.

18. A polyisocyanate composition, characterized in that: The method is prepared in the presence of the isocyanate self-polymerization catalyst according to claim 1 or 2 or the isocyanate self-polymerization catalyst prepared by the method according to any one of claims 3 to 17.

19. A method for preparing the polyisocyanate composition according to claim 18, characterized in that: The invention is prepared by oligomerization reaction of at least one isocyanate monomer having an NCO functionality > 1 in the presence of the isocyanate self-polymerization catalyst according to claim 1 or 2 or the isocyanate self-polymerization catalyst prepared by the method according to any one of claims 3 to 17.

20. The preparation method according to claim 19, characterized in that: The isocyanate monomer is selected from aliphatic diisocyanates; The diisocyanate has a hydrolyzed chlorine content of 5-500 ppm; and / or The isocyanate self-polymerization catalyst is added in the form of an alcohol solution; The usage amount of the catalyst is 0.001-5% of the mass of the isocyanate.

21. The preparation method according to claim 20, characterized in that: The isocyanate monomer is selected from 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, 4-isocyanatomethyl-1,8-octane diisocyanate, 3(4)-isocyanatomethyl-1-methylcyclohexyl isocyanate, isophorone diisocyanate, 1,3- and 1,4-bis(isocyanatomethyl)benzene, and 1,3- and 1,4-bis(isocyanatomethyl)cyclohexane.

22. The preparation method according to claim 20, characterized in that: The mass concentration of the isocyanate self-polymerization catalyst in the alcohol is 1-50%.

23. The preparation method according to claim 20, characterized in that: The usage amount of the catalyst is 0.002-2% of the mass of the isocyanate.

24. The preparation method according to claim 19, characterized in that: The oligomerization reaction is carried out at a temperature of 20°C to 100°C; The end point of the oligomerization reaction is an NCO conversion rate of 10-80wt%; The oligomerization reaction is terminated by deactivating the catalyst; After the reaction is terminated, the unreacted monomers are separated by any one of thin film evaporation, falling film evaporation, short path evaporation and vacuum distillation.

25. The preparation method according to claim 24, characterized in that: The oligomerization reaction temperature is 40-80°C.

26. The preparation method according to claim 24, characterized in that: The end point of the oligomerization reaction is an NCO conversion rate of 20-70 wt %.

27. The preparation method according to claim 24, characterized in that: The oligomerization reaction is carried out by adding an acid or an acid derivative, or by thermal decomposition to deactivate the catalyst.

28. The preparation method according to claim 24, characterized in that: The method for separating the unreacted monomers is two-stage thin film evaporation.

Images