Aromatic polyurethane as well as preparation method and application thereof

Abstract

The invention discloses high-aroma polyurethane which is derived from the following monomers in percentage by mole: 49.5-50.5 mol% of diisocyanate unit, 49.5-50.5 mol% of polyisocyanate unit, 49.5-50.5 mol% of polyisocyanate unit and 49.5- A diol unit is 49.5 to 50.5 mol%; wherein in the diisocyanate unit, the molar ratio of the aromatic diisocyanate to the other diisocyanate is (60 to 99): (1 to 40); in the diol unit, the molar ratio of aromatic diether diol to other dihydric alcohols is (60-99): (1-40); the aromatic diether glycol with a specific structural unit is introduced into the polyurethane, so that the transparency, hardness and heat resistance of the polyurethane can be effectively improved, and the polyurethane has good mechanical properties.

Description

Technical Field

[0001] The invention relates to the technical field of polymer materials, in particular to an aromatic polyurethane and a preparation method thereof. Background Art

[0002] The main raw materials of polyurethane are diols and diisocyanates. The soft segments and hard segments of polyurethane are embedded in each other, which makes it have excellent material properties, so it is widely used in many fields such as electrical appliances, automobiles, and engineering parts. In general, polyurethane has defects such as decreased heat resistance and high brittleness at high temperatures, which further limits the wide application of the polymer. Therefore, how to improve the heat resistance, hardness and transparency of polyurethane while maintaining its comprehensive performance is a major challenge in the research of engineering-grade thermoplastic polyurethane. In the prior art, most polyurethanes have poor heat resistance. Polyurethane is easy to soften at high temperatures, and its hardness and heat resistance deteriorate. In addition, polyurethane still has the defect of low transparency.

[0003] Most existing technologies enhance the performance of polymers by adding a series of physical modifiers. This method has the disadvantages of complex synthesis process and poor adhesion of the modified materials, which ultimately severely limits the further application of polyurethane in engineering materials. A small number of studies have used aromatic diols (such as aromatic diols containing sulfone groups) as monomer additives to synthesize high-performance polyurethanes, but due to the poor solubility of such diols in non-polar solvents and the tendency of bulk polymerization to climb the pole, high molecular weight polyurethane products cannot be obtained.

[0004] For example, Chinese patent application CN105669929A ​​discloses a method for preparing engineering-grade thermoplastic polyurethane. It mainly uses diols, diisocyanates and modified materials to be put into a twin-screw extruder to prepare polyurethane TPU in one step. The diols used in this patent are mainly small molecules such as butanediol, hexanediol, cyclohexanedimethanol, and triethylene glycol. This invention prepares polyurethane with higher hardness by adding modified materials, but the transparency and heat resistance still need to be improved.

[0005] For example, Chinese patent application CN111171279A discloses a method for preparing a sulfone-containing polymer. The patent uses MDI and polytetrahydrofuran ether diol for prepolymerization, and the prepolymer is further polymerized with bishydroxyethyl bisphenol S to obtain a sulfone-containing polyurethane. The polymer has excellent heat resistance and mechanical properties, but the transparency needs to be improved. Summary of the invention

[0006] The purpose of the present invention is to overcome the above technical defects and provide an aromatic polyurethane with high transparency, high hardness, good heat resistance and good mechanical properties.

[0007] The present invention is achieved through the following technical solutions:

[0008] An aromatic polyurethane derived from monomers comprising, by mole percentage:

[0009] Diisocyanate units 49.5-50.5 mol%;

[0010] Diol units 49.5-50.5 mol%;

[0011] Among them, in the diisocyanate unit, the molar ratio of aromatic diisocyanate to other diisocyanates is (60-99):(1-40); in the diol unit, the molar ratio of aromatic diether diol to other diols is (60-99):(1-40);

[0012] The aromatic diisocyanate is selected from any one or more of 2,6-toluene diisocyanate, o-phenylenediisocyanate, diphenylmethane diisocyanate, 3,3'-dichlorobiphenyl-4,4'-diisocyanate, 1,5-naphthalene diisocyanate, m-phenylene diisocyanate, 4-chloro-6-methylm-phenylene diisocyanate, dimethylbiphenyl diisocyanate, 2,4,6-triisopropylm-phenylene diisocyanate, and 2,2'-methylene diphenyl diisocyanate;

[0013] The other diisocyanates are selected from any one or more of trimethylhexamethylene diisocyanate, polyhexamethylene diisocyanate, 1,6-hexamethylene diisocyanate, isophorone diisocyanate, cyclohexane-1,4-diisocyanate, 1,4-cyclohexane dimethyl diisocyanate, 1,3-bis(isocyanatomethyl)cyclohexane, methylene diisocyanate, dicyclohexylmethane diisocyanate, trimethylhexamethylene diisocyanate, and 1,5-diisocyanatopentane;

[0014] The aromatic diether diol has the following molecular structure:

[0015]

[0016]

[0017] Among them, R is Where n is a positive integer from 1 to 3.

[0018] Among them, R 1 for Any one of, wherein n is a positive integer from 1 to 3,

[0019] Among them, R 2 for Any one of, wherein n is a positive integer from 1 to 3;

[0020] The other diols are selected from at least one of ethylene glycol, diethylene glycol, methyl propylene glycol, 2-phenyl-1,3-propanediol, 2-butyl-2-ethyl-1,3-propanediol, 2,2-dimethyl-1,3-propanediol, polyethylene glycol, 1,4-cyclohexanedimethanol, spirodiol, 1,2-propanediol, 1,3-propanediol, 1,3-adamantanediol, neopentyl glycol, hexanediol, octanediol, 2,3-butanediol, 1,3-butanediol, 1,4-butanediol, and 1,5-pentanediol.

[0021] Preferably, the aromatic polyurethane is derived to include the following monomers, measured by mole percentage:

[0022] Diisocyanate units 49.5-50.5 mol%;

[0023] Diol units 49.5-50.5 mol%;

[0024] Among them, in the diisocyanate unit, the molar ratio of aromatic diisocyanate to other diisocyanates is (70-99):(1-30); in the diol unit, the molar ratio of aromatic diether diol to other diols is (70-99):(1-30).

[0025] More preferably, the aromatic polyurethane is derived to include the following monomers, measured by mole percentage:

[0026] Diisocyanate units 49.5-50.5 mol%;

[0027] Diol units 49.5-50.5 mol%;

[0028] Among them, in the diisocyanate unit, the molar ratio of aromatic diisocyanate to other diisocyanates is (75-99):(1-25); in the diol unit, the molar ratio of aromatic diether diol to other diols is (80-99):(1-20).

[0029] Preferably, the aromatic diisocyanate is selected from any one of 2,6-toluene diisocyanate, o-phenylenediisocyanate, diphenylmethane diisocyanate, and 2,2'-methylene diphenyl diisocyanate;

[0030] Preferably, the other diisocyanate is selected from any one or more of trimethylhexamethylene diisocyanate, isophorone diisocyanate and methylene diisocyanate.

[0031] Preferably, the aromatic diether diol is selected from

[0032] Preferably, the other diol is selected from at least one of diethylene glycol and 1,4-butanediol.

[0033] The molecular weight range of the aromatic polyurethane is w =80,000-140,000.

[0034] The polymerization method of the aromatic polyurethane of the present invention comprises the following steps:

[0035] S1: Add aromatic diether diol, other diols and solvent into the reaction vessel, reduce the pressure to 0.01-10Kpa, raise the temperature to 110-160°C, remove water for 2-4 hours, cool the system to 15-30°C, introduce inert gas protection, and restore the system to normal pressure;

[0036] S2: Under the protection of inert gas, the system is slowly added with aromatic diisocyanate at 10-40°C for 0.5-3 hours, the temperature is raised to 20-35°C for reaction for 3-4 hours, other diisocyanates are added at once, the temperature is raised to 50-90°C for reaction for 1-2 hours, a catalyst is added to further carry out polycondensation reaction for 1-3 hours, and after reaching a predetermined viscosity, the material is discharged to obtain a crude polyurethane product; the crude product is crushed, washed with water for multiple times, and dried to obtain purified polyurethane.

[0037] The polymerization method of aromatic polyurethane of the present invention comprises the following steps: the solvent is selected from at least one of N,N-dimethylformamide, xylene, N,N-dimethylacetamide, N-methylpyrrolidone, cyclohexanone, sulfolane, dimethyl sulfoxide, toluene, dodecane and 1,4-dioxane, wherein the solid content in the reaction system is 10-40wt%; the catalyst is selected from at least one of dibutyltin dilaurate, stannous octoate, tetramethylethylenediamine, tetramethylpropylenediamine, 1,4-dimethylpiperazine, dimethylbenzylamine, triethylenediamine, hydroxyethylpropylenediamine, ethylene glycol antimony, antimony trioxide and antimony triacetate, and the addition amount thereof is in the range of 5-100ppm.

[0038] The aromatic polyurethane of the invention can be applied to products with high requirements on transparency and hardness, such as electronic components, plastic screws, and automobile oil-water separators.

[0039] The present invention has the following beneficial effects:

[0040] The present invention provides an engineering-grade thermoplastic polyurethane having high transparency, high hardness and heat resistance by polymerizing a highly conjugated aromatic diol with a diisocyanate. Specifically, 1. the aromatic diether diol of the present invention increases the transparency and mechanical properties of the polymer, 2. the highly conjugated structure in the diol monomer enables the polymer to have better heat resistance and high hardness, and 3. a certain amount of alkyl chains and ether bonds increase the ductility of the polyurethane. DETAILED DESCRIPTION

[0041] The present invention is described in detail below in conjunction with specific embodiments. The following embodiments will help those skilled in the art to further understand the present invention, but are not intended to limit the present invention in any form. It should be noted that, for those of ordinary skill in the art, several variations and improvements may be made without departing from the concept of the present invention. These all belong to the protection scope of the present invention.

[0042] The sources of raw materials used in the present invention are as follows:

[0043] The following aromatic diisocyanates are commercially available:

[0044] 2,6-toluene diisocyanate (label A in the table), o-phenylenediisocyanate (label B in the table), diphenylmethane diisocyanate (label C in the table), 2,2'-methylenediphenyl diisocyanate (label D in the table), 3,3'-dichlorobiphenyl-4,4'-diisocyanate (label E in the table), 1,5-naphthalene diisocyanate (label F in the table), dimethylbiphenyl diisocyanate (label G in the table);

[0045] The following other sources of diisocyanates are derived from commercially available products:

[0046] Trimethylhexamethylene diisocyanate (label A in the table), isophorone diisocyanate (label B in the table), methylene diisocyanate (label C in the table), 1,6-hexamethylene diisocyanate (label D in the table), 1,3-bis(isocyanatomethyl)cyclohexane (label E in the table), dicyclohexylmethane diisocyanate (label F in the table), trimethylhexamethylene diisocyanate (label G in the table);

[0047] Aromatic diether diol A: Commercially available

[0048]

[0049] Aromatic diether diol B: Commercially available

[0050]

[0051] Aromatic diether diol C: Commercially available

[0052]

[0053] Aromatic diether diol D: Commercially available

[0054] Aromatic diether diol E: Commercially available

[0055] Aromatic diol F: Commercially available

[0056] Bisphenol A diether glycol G: Commercially available

[0057] Bisphenol type diether diol H: Commercially available

[0058] Bisphenol A diether diol I: Commercially available

[0059] Bisphenol F type diether diol J: Commercially available

[0060]

[0061] Bisphenol A diether diol K: Commercially available

[0062]

[0063] The following other diols are from commercially available products:

[0064] Diethylene glycol (label A in the table), 1,4-butanediol (label B in the table), 2-phenyl-1,3-propanediol (label C in the table), 1,4-cyclohexanedimethanol (label D in the table), and 1,3-adamantanediol (label E in the table).

[0065] Polymerization method of aromatic polyurethane in the embodiment and comparative example: S1: Add aromatic diether diol, other diols, and solvent (N-methylpyrrolidone (solid content 30%)) into a reaction vessel, reduce the pressure to 0.01-10Kpa, raise the temperature to 110-160°C, remove water for 2-4 hours, cool the system to 15-30°C, introduce inert gas protection (nitrogen), and restore the system to normal pressure; S2: Under the protection of inert gas, slowly add aromatic polyol at 10-40°C The diisocyanate is added for 0.5-3 hours, the temperature is raised to 20-35°C for reaction for 3-4 hours, other diisocyanates are added at once, the temperature is raised to 50-90°C for reaction for 1-2 hours, a catalyst (dibutyltin dilaurate (20ppm) and dimethylbenzylamine (15ppm)) is added to further carry out polycondensation reaction for 1-3 hours, and after reaching a predetermined viscosity, the material is discharged to obtain a crude polyurethane product; the crude product is crushed, washed with water for multiple times, and dried to obtain a purified aromatic polyurethane.

[0066] Various test methods:

[0067] (1) Transparency: Test method refers to ASTM D1003;

[0068] (2) Impact strength: The test method refers to standard ISO180;

[0069] (3) Tensile strength: test method refers to ISO 527;

[0070] (4) Hardness: Test method refers to ASTM D2240;

[0071] (5) Heat resistance: test method refers to ASTM D648;

[0072] (6) Molecular weight: The test method refers to gel permeation chromatography.

[0073] Table 1: Mol content of each unit of aromatic polyurethane in Examples and Comparative Examples and test results

[0074]

[0075]

[0076] It can be seen from Examples 1-7 that the preferred aromatic diisocyanate has better comprehensive properties when compared with other diisocyanates.

[0077] Table 1 continued:

[0078]

[0079]

[0080] It can be seen from Examples 1 / 8-17 that the aromatic diether diol is selected from A / B / C / D / G / I, etc.

[0081] Table 1 continued:

[0082]

[0083] It can be seen from Examples 1 / 18-21 that the other diol is preferably at least one of diethylene glycol and 1,4-butanediol.

[0084] Table 1 continued:

[0085]

[0086]

[0087] It can be seen from Examples 1 / 22-26 that the preferred molar ratio of aromatic diisocyanate: other diisocyanates and the molar ratio of aromatic diether diol: other diols provide better comprehensive performance.

[0088] Table 1 continued:

[0089]

[0090]

[0091] It can be seen from the comparative examples that the aromatic polyurethane of the present invention has better performance than other polyurethanes.

Claims

1. An aromatic polyurethane, characterized in that: Derivatized to include the following monomers, measured by mole percentage: Diisocyanate units 49.5-50.5 mol%; Diol units 49.5-50.5 mol%; Wherein, in the diisocyanate unit, the molar ratio of aromatic diisocyanate to other diisocyanates is (60-99):(1-40); In the diol unit, the molar ratio of aromatic diether diol to other diols is (60-99):(1-40); The aromatic diisocyanate is selected from any one or more of 2,6-toluene diisocyanate, o-phenylenediisocyanate, diphenylmethane diisocyanate, 3,3'-dichlorobiphenyl-4,4'-diisocyanate, 1,5-naphthalene diisocyanate, m-phenylene diisocyanate, 4-chloro-6-methylm-phenylene diisocyanate, dimethylbiphenyl diisocyanate, 2,4,6-triisopropylm-phenylene diisocyanate, 2,2'-methylene diphenyl diisocyanate. The other diisocyanates are selected from any one or more of trimethylhexamethylene diisocyanate, polyhexamethylene diisocyanate, 1,6-hexamethylene diisocyanate, isophorone diisocyanate, cyclohexane-1,4-diisocyanate, 1,4-cyclohexane dimethyl diisocyanate, 1,3-bis(isocyanatomethyl)cyclohexane, methylene diisocyanate, dicyclohexylmethane diisocyanate, trimethylhexamethylene diisocyanate, and 1,5-diisocyanatopentane; The aromatic diether diol is at least one of the following molecular structures: Among them, R is Where n is a positive integer from 1 to 3. Among them, R 1 for Any one of, wherein n is a positive integer from 1 to 3, Among them, R 2 for Any one of, wherein n is a positive integer from 1 to 3; The other diols are selected from at least one of ethylene glycol, diethylene glycol, methyl propylene glycol, 2-phenyl-1,3-propanediol, 2-butyl-2-ethyl-1,3-propanediol, 2,2-dimethyl-1,3-propanediol, polyethylene glycol, 1,4-cyclohexanedimethanol, spirodiol, 1,2-propanediol, 1,3-propanediol, 1,3-adamantanediol, neopentyl glycol, hexanediol, octanediol, 2,3-butanediol, 1,3-butanediol, 1,4-butanediol, and 1,5-pentanediol.

2. The aromatic polyurethane according to claim 1, characterized in that Derivatized to include the following monomers, measured by mole percentage: Diisocyanate units 49.5-50.5 mol%; Diol units 49.5-50.5 mol%; Wherein, in the diisocyanate unit, the molar ratio of aromatic diisocyanate to other diisocyanates is (70-99):(1-30); In the diol unit, the molar ratio of aromatic diether diol to other diols is (70-99):(1-30).

3. The aromatic polyurethane according to claim 2, characterized in that Derivatized to include the following monomers, measured by mole percentage: Diisocyanate units 49.5-50.5 mol%; Diol units 49.5-50.5 mol%; Wherein, in the diisocyanate unit, the molar ratio of aromatic diisocyanate to other diisocyanates is (75-99):(1-25); In the diol unit, the molar ratio of aromatic diether diol to other diols is (80-99):(1-20).

4. The aromatic polyurethane according to claim 1, characterized in that The aromatic diisocyanate is selected from any one of 2,6-toluene diisocyanate, o-phenylenediisocyanate, diphenylmethane diisocyanate, and 2,2'-methylene diphenyl diisocyanate; The other diisocyanate is selected from any one or more of trimethylhexamethylene diisocyanate, isophorone diisocyanate, and methylene diisocyanate; The other diols are selected from at least one of diethylene glycol and 1,4-butanediol.

5. The aromatic polyurethane according to claim 1, characterized in that The aromatic diether diol is selected from 6. The aromatic polyurethane according to any one of claims 1 to 5, characterized in that: The molecular weight range of the aromatic polyurethane is w =80,000-140,000.

7. The method for polymerizing an aromatic polyurethane according to any one of claims 1 to 6, characterized in that: The following steps are involved: S1: Add aromatic diether diol, other diols and solvent into the reaction vessel, reduce the pressure to 0.01-10Kpa, raise the temperature to 110-160°C, remove water for 2-4 hours, cool the system to 15-30°C, introduce inert gas protection, and restore the system to normal pressure; S2: Under the protection of inert gas, the system is slowly added with aromatic diisocyanate at 10-40°C for 0.5-3 hours, the temperature is raised to 20-35°C for reaction for 3-4 hours, other diisocyanates are added at once, the temperature is raised to 50-90°C for reaction for 1-2 hours, a catalyst is added to further carry out polycondensation reaction for 1-3 hours, and after reaching a predetermined viscosity, the material is discharged to obtain a crude polyurethane product; the crude product is crushed, washed with water for multiple times, and dried to obtain a purified aromatic polyurethane.

8. The method for polymerizing aromatic polyurethane according to claim 7, characterized in that: The solvent is selected from at least one of N,N-dimethylformamide, xylene, N,N-dimethylacetamide, N-methylpyrrolidone, cyclohexanone, sulfolane, dimethyl sulfoxide, toluene, dodecane, and 1,4-dioxane, wherein the solid content in the reaction system is 10-40wt%; the catalyst is selected from at least one of dibutyltin dilaurate, stannous octoate, tetramethylethylenediamine, tetramethylpropylenediamine, 1,4-dimethylpiperazine, dimethylbenzylamine, triethylenediamine, hydroxyethylpropylenediamine, ethylene glycol antimony, antimony trioxide, and antimony triacetate, and the addition amount ranges from 5-100ppm.

9. The use of the aromatic polyurethane according to any one of claims 1 to 6, characterized in that: Used to prepare transparent parts.

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