Thermoplastic polyurethane precursor, thermoplastic polyurethane as well as preparation method and application of thermoplastic polyurethane

Abstract

The invention relates to a thermoplastic polyurethane precursor which can be used for preparing thermoplastic polyurethane with low initial chroma, high yellowing resistance, high thermo-oxidative aging resistance, high hydrolysis resistance and low crystal point. The thermoplastic polyurethane precursor comprises a polyisocyanate, a chain extender, a polymer polyol and a first auxiliary agent, and the first auxiliary agent comprises (d1) phenylpropionic acid-3, 5-bis (1, 1-dimethylethyl)-4-hydroxy-C7-C9 branched alkyl ester, (d2) phenylpropionic acid-3, 5-bis (1, 1-dimethylethyl)-4-hydroxy-C7-C9 branched alkyl ester, (d3) phenylpropionic acid-3, 5-bis (1, 1-dimethylethyl)- (d2) mixing phosphorous acid with 2, 4-bis (1, 1-dimethyl propyl) phenyl and 4-(1, 1-dimethyl propyl) phenyl triester; (d3) 4-tert-butyl-2-(5-tert-butyl-2-oxy-3H-benzofuran-3-yl) phenyl-3, 5-di-tert-butyl-4-hydroxybenzoate, and (d4) 4-tert-butyl-2-(5-tert-butyl-2-oxy-3H-benzofuran-3-yl) And (d4) at least one of a compound of formula (I) and a compound of formula (II) [Formula (I)] # imgabs0 # wherein R1 is a C12 alkenyl group; [Formula (II)] # imgabs1 #

Description

Technical Field

[0001] The present invention relates to a thermoplastic polyurethane precursor, in particular to a thermoplastic polyurethane precursor containing a specific auxiliary agent. The present invention also relates to a thermoplastic polyurethane prepared from the thermoplastic polyurethane precursor and a preparation method and application thereof. Background Art

[0002] Thermoplastic polyurethane is a thermoplastic elastomer, which is a linear segment copolymer composed of rigid segments and flexible segments. Thermoplastic polyurethane is obtained by reacting polyisocyanate, polymer polyol, and chain extender together, wherein the rigid segment is obtained by reacting polyisocyanate with chain extender, and the flexible segment is obtained by reacting polyisocyanate with polymer polyol. Generally speaking, by adjusting the proportion of raw materials, thermoplastic polyurethane with desired mechanical properties can be manufactured, and the mechanical properties include wear resistance, temperature resistance, flexibility, elongation, etc. Thermoplastic polyurethane can usually withstand low temperatures of about -40°C and high temperatures of about 120°C. In addition, thermoplastic polyurethane usually has excellent load-bearing capacity, impact resistance, elasticity, toughness, and aging resistance, and can also withstand oil and aliphatic hydrocarbon solvents, and is resistant to oxygen and ozone. Therefore, thermoplastic polyurethane can be widely used in various technical fields, including but not limited to coatings, elastomers, foaming materials, adhesives, and sealants.

[0003] The preparation method of thermoplastic polyurethane includes but is not limited to the preparation method commonly known as the "one-shot method", in which all raw materials (including polymer polyol, polyisocyanate, chain extender, etc.) are fed into a twin-screw extruder according to a proportion to obtain a colloid of thermoplastic polyurethane with high viscosity. The colloid is matured at 70°C to 100°C and then processed to form a film product. However, the yellowing problem of thermoplastic polyurethane and especially the fisheye problem of its film product have always been difficult to solve in the industry.

[0004] The crystal point problem is a common technical difficulty in the processing of thermoplastic polyurethane films. Especially for transparent films, the presence of crystal points will seriously affect the appearance of the film. Therefore, the waste and defective products caused by crystal points are a large proportion of losses in the thermoplastic polyurethane film industry and need to be solved urgently.

[0005] Generally speaking, the causes of crystal points in thermoplastic polyurethane films are "mechanical impurities" or "excessive polymers". "Mechanical impurities" are impurities that enter thermoplastic polyurethane from the outside during the manufacturing and processing process, which can be improved through process management and cleaning. "Excessive polymers" refer to dimers or polymers of polyisocyanates, or high-melting point molecules such as urea and biuret produced by side reactions. During film processing, the polymers at the crystal points will agglomerate and harden prematurely and cannot be evenly dispersed and mixed with the surrounding polymers, thus forming granular or arrow-shaped marks on the film surface.

[0006] In addition, the high reaction temperature and high mixing shear force in the process of preparing thermoplastic polyurethane using a twin-screw extruder will make the color of thermoplastic polyurethane (especially aromatic thermoplastic polyurethane) yellowish. The use of hindered phenol antioxidants can at most avoid the degradation of molecular weight, and cannot effectively inhibit yellowing. In addition, although the use of phosphite antioxidants can effectively inhibit yellowing during the reaction, it will cause the thermoplastic polyurethane to hydrolyze. Although it can be inhibited by adding a large amount of carbodiimide-type anti-hydrolysis agents, the addition of anti-hydrolysis agents not only increases costs, but also has the problem of additive spitting out.

[0007] Therefore, there is still a need for a thermoplastic polyurethane with low chroma, high yellowing resistance, high heat-oxidative aging resistance, high hydrolysis resistance and low crystal point. Summary of the invention

[0008] The inventors have found that the combination of a compound having a 3,5-di-tert-butyl-4-hydroxyphenylpropionamide structure, a specific hindered phenol antioxidant, a specific liquid phosphite antioxidant, and a specific lactone antioxidant in the formulation for preparing thermoplastic polyurethane can provide an unexpected synergistic effect, so that the prepared thermoplastic polyurethane has the characteristics of low chroma, high yellowing resistance, high heat-oxidative aging resistance, high hydrolysis resistance, and low crystal point.

[0009] Therefore, an object of the present invention is to provide a thermoplastic polyurethane precursor, which comprises:

[0010] (A) polyisocyanate;

[0011] (B) a chain extender;

[0012] (C) polymer polyols; and

[0013] (D) a first auxiliary agent, comprising:

[0014] (d1) phenylpropionic acid-3,5-bis(1,1-dimethylethyl)-4-hydroxy-C7-C9 branched alkyl ester;

[0015] (d2) Phosphorous acid mixed with 2,4-bis(1,1-dimethylpropyl)phenyl and 4-(1,1-dimethylpropyl)phenyl triester;

[0016] (d3) 4-tert-butyl-2-(5-tert-butyl-2-oxo-3H-benzofuran-3-yl)phenyl-3,5-di-tert-butyl-4-hydroxybenzoate; and

[0017] (d4) at least one of a compound of formula (I) and a compound of formula (II),

[0018] [Formula (I)]

[0019]

[0020] Wherein R1 is C12 alkenyl;

[0021] [Formula (II)]

[0022]

[0023] In some embodiments of the present invention, the polyisocyanate (A) comprises an aromatic polyisocyanate.

[0024] In some embodiments of the present invention, the polymer polyol (C) is selected from the following group: polyether polyol, polyester polyol, polysiloxane polyol, and combinations thereof.

[0025] In some embodiments of the present invention, the chain extender (B) is selected from the following group: polyols, diamines, amino alcohols, and combinations thereof.

[0026] In some embodiments of the present invention, based on the total weight of the thermoplastic polyurethane precursor, the content of components (d1) to (d4) is independently 0.01 wt % to 1.0 wt %.

[0027] In some embodiments of the present invention, the thermoplastic polyurethane precursor further comprises an additive selected from the following groups: defoaming agent, leveling wetting agent, thickener, dispersant, wax, matting powder, antibacterial agent, metal oxide light shielding agent, light stabilizer, heat stabilizer, ultraviolet light absorber, blue light absorber, antioxidant, peroxide scavenger, free radical scavenger, filler, rubber (including silicone rubber), food preservative, flame retardant, plasticizer, dye, pigment (including titanium dioxide, carbon black), brightener, antistatic agent (including graphene, carbon nanotubes), fluorescent whitening agent, antioxidant, metal stabilizer, acid absorber, anti-hydrolysis agent and a combination thereof.

[0028] Another object of the present invention is to provide a thermoplastic polyurethane, which comprises a first auxiliary agent, wherein the first auxiliary agent comprises:

[0029] (d1) 3,5-bis(1,1-dimethylethyl)-4-hydroxy-C7-C9 branched alkyl phenyl ester; (d2) phosphorous acid mixed with 2,4-bis(1,1-dimethylpropyl)phenyl and 4-(1,1-dimethylpropyl)phenyl triester;

[0030] (d3) 4-tert-butyl-2-(5-tert-butyl-2-oxo-3H-benzofuran-3-yl)phenyl-3,5-di-tert-butyl-4-hydroxybenzoate; and

[0031] (d4) at least one of a compound of formula (I) and a compound of formula (II),

[0032] [Formula (I)]

[0033]

[0034] Wherein R1 is C12 alkenyl;

[0035] [Formula (II)]

[0036]

[0037] In some embodiments of the present invention, the thermoplastic polyurethane further comprises an additive selected from the following groups: defoaming agent, leveling wetting agent, thickener, dispersant, wax, matting powder, antibacterial agent, metal oxide light shielding agent, light stabilizer, heat stabilizer, ultraviolet light absorber, blue light absorber, antioxidant, peroxide scavenger, free radical scavenger, filler, rubber (including silicone rubber), food preservative, flame retardant, plasticizer, dye, pigment (including titanium dioxide, carbon black), brightener, antistatic agent (including graphene, carbon nanotubes), fluorescent whitening agent, antioxidant, metal stabilizer, acid absorber, anti-hydrolysis agent and a combination thereof.

[0038] Another object of the present invention is to provide a method for preparing thermoplastic polyurethane, which comprises the following steps:

[0039] Providing a thermoplastic polyurethane precursor as described above; and

[0040] The thermoplastic polyurethane precursor is subjected to a polymerization reaction to obtain a thermoplastic polyurethane.

[0041] In some embodiments of the present invention, the method for preparing thermoplastic polyurethane further comprises pelletizing, extruding, laminating, injection molding, calendering, casting, film blowing, coating, melt blowing or drawing on the thermoplastic polyurethane.

[0042] Another object of the present invention is to provide a use of the thermoplastic polyurethane as described above in the preparation of thermoplastic polyurethane products with low chroma, high yellowing resistance, high heat-oxidative aging resistance, high hydrolysis resistance and low crystallinity.

[0043] In some embodiments of the present invention, the thermoplastic polyurethane product is selected from the following groups: transparent shells, packaging products, daily necessities, textiles, medical products, sporting goods, electronic products, optical products, construction products, mechanical parts, automotive products, military industrial products, and coatings.

[0044] In order to make the above-mentioned objectives, technical features and advantages of the present invention more obvious and easy to understand, some specific implementation schemes are described in detail below. DETAILED DESCRIPTION

[0045] Some specific embodiments according to the present invention will be described in detail below; however, the present invention can also be practiced in a variety of different forms, and the protection scope of the present invention should not be limited to the specific embodiments.

[0046] Unless otherwise stated, the terms “a”, “an”, “the” and similar terms used in the specification and claims should be understood to include both the singular and the plural.

[0047] Unless otherwise specified, the terms “first”, “second” and the like used in the specification and the claims are merely used to distinguish the described elements or components and have no special meanings and are not used to represent a sequence.

[0048] Unless otherwise indicated, the weight of the solvent is not included when describing the components contained in the solution, mixture, precursor or thermoplastic polyurethane in this specification and claims.

[0049] Thermoplastic polyurethane, also known as thermoplastic polyurethane, is a polymer containing a characteristic unit of urethane in the main chain. Generally speaking, the urethane group can be obtained by reacting an isocyanate functional group (-N=C=O) with a hydroxyl group (-OH). Therefore, the precursors generally used to prepare thermoplastic polyurethane include polyisocyanates and polyols. In addition, a chain extender can be further added to extend the molecular chain of the polyurethane and increase the molecular weight.

[0050] The present invention has the effect of providing a thermoplastic polyurethane with low chroma, high yellowing resistance, high heat-oxidative aging resistance, high hydrolysis resistance and low crystal point by combining a compound having a 3,5-di-tert-butyl-4-hydroxyphenylpropionamide structure, a specific hindered phenol antioxidant, a specific liquid phosphite antioxidant and a specific lactone antioxidant in the formula of the thermoplastic polyurethane precursor. The following is a detailed description of the thermoplastic polyurethane precursor of the present invention and its application.

[0051] 1. Thermoplastic polyurethane precursor

[0052] The thermoplastic polyurethane precursor of the present invention comprises (A) polyisocyanate, (B) chain extender, (C) polymer polyol, and (D) first auxiliary agent.

[0053] 1.1. Polyisocyanate (A)

[0054] The polyisocyanate (A) may be an aliphatic polyisocyanate or an aromatic polyisocyanate, and is preferably an aromatic polyisocyanate.

[0055] Examples of the polyisocyanate (A) include, but are not limited to, methylenediphenyl diisocyanate (MDI), m-xylylene diisocyanate (XDI), toluene-2,4-diisocyanate (TDI), trimethylene diisocyanate, tetramethylene diisocyanate, pentamethylene diisocyanate, hexamethylene diisocyanate, heptamethylene diisocyanate, octamethylene diisocyanate, toluene-2,6-diisocyanate, 3,3'-dimethoxy-4,4'-diisocyanatobiphenyl ester, 3,3'-dichloro-4,4'-diisocyanatobiphenyl ester, 1,4-phenylene diisocyanate, isophorone diisocyanate (IPDI), 1,4-cyclohexylene diisocyanate (1,4-cyclohexylene diisocyanate), and the like. diisocyanate (CHDI), decane-1,10-diisocyanate, lysine diisocyanate (LDI), 1,4-butane diisocyanate (BDI), 3,3'-dimethyl-4,4'-biphenylene diisocyanate (TODI), 1,5-naphthyl diisocyanate (naphthalene-1.5-diisocyanate, NDI), dicyclohexylmethane-4,4'-diisocyanate (4,4'-diisocyanato dicyclohexylmethane, H12MDI), 2-methylpentamethylene-1,5-diisocyanate, 2-ethylbutane-1,4-diisocyanate, 1-isocyanate-3,3,5-trimethyl-5-isocyanatemethylcyclohexane, 1,4-bis(isocyanatemethyl)cyclohexane, 1,4-cyclohexane diisocyanate, 1-methyl-2,4-cyclohexane diisocyanate, 1-methyl-2,6-cyclohexane diisocyanate, 2,2'-dicyclohexylmethane diisocyanate, 2,4-dicyclohexylmethane diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, 3,3'-dimethylbiphenyl diisocyanate, and 1,2-diphenylethane diisocyanate. The aforementioned polyisocyanates may be used alone or in combination. In the following examples, the polyisocyanate (A) is diphenylmethane diisocyanate (MDI).

[0056] Based on the total weight of the thermoplastic polyurethane precursor, the content of polyisocyanate (A) may be 0.01 wt % to 50 wt %, for example, 0.01 wt %, 0.05 wt %, 0.1 wt %, 0.5 wt %, 1 wt %, 2 wt %, 3 wt %, 4 wt %, 5 wt %, 6 wt %, 7 wt %, 8 wt %, 9 wt %, 10 wt %, 11 wt %, 12 wt %, 13 wt %, 14 wt %, 15 wt %, 16 wt %, 17 wt %, 18 wt %, 19 wt %, 20 wt %, 21 wt %, 22 wt %, 23 wt %, 24 wt %, 25 wt %, 26 wt %, 27 wt %, 28 wt %, 29 wt %, 30 wt %, 31 wt %, 32 wt %, 33 wt %, 34 wt %, 35 wt %, 36 wt %, 37 wt %, 38 wt %, 39 wt %, 40 wt %, 41 wt %, 42 wt %, 43 wt %, 44 wt %, 45 wt %, 46 wt %, 47 wt %, 48 wt %, 49 wt %, 50 wt %, 51 2 weight %, 23 weight %, 24 weight %, 25 weight %, 26 weight %, 27 weight %, 28 weight %, 29 weight %, 30 weight %, 31 weight %, 32 weight %, 33 weight %, 34 weight %, 35 weight %, 36 weight %, 37 weight %, 38 weight %, 39 weight %, 40 weight %, 41 weight %, 42 weight %, 43 weight %, 44 weight %, 45 weight %, 46 weight %, 47 weight %, 48 weight %, 49 weight %, or 50 weight %, or within the range consisting of any two of the above values.

[0057] 1.2. Chain extender (B)

[0058] The chain extender (B) may be selected from the following groups: polyols, diamines, amino alcohols, and combinations thereof. Examples of polyols include, but are not limited to, diols and triols. Examples of diols include, but are not limited to, ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-butanediol, 2,3-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,4-cyclohexanedimethanol, 2-butyl-2-ethylpropylene glycol, neopentyl glycol, 2,2,4-trimethyl-1,3-pentanediol, 2-ethyl-1,3-hexanediol, and 1,4-cyclohexanediol. Examples of triols include, but are not limited to, trimethylolpropane, glycerol, and 1,2,6-hexanetriol. Examples of diamines include, but are not limited to, ethylenediamine, propylenediamine, 1,4-butylenediamine, 1,6-hexanediamine, N,N'-diisobutyl-1,6-hexanediamine, 1,11-diaminoundecane, 1,12-diaminododecane, 1,3-cyclobutylenediamine, 1,3-cyclohexanediamine, 1,4-cyclohexanediamine, p-phenylenediamine, bis-(3-aminopropyl)-methylamine, 3,3'-dichloro-4,4'-diamino-diphenylmethane, toluenediamine, 4,4'-diaminodiphenylmethane, and 4,4'-diaminodiphenyl disulfide. Examples of amino alcohols include, but are not limited to, ethanolamine, propanolamine, butanolamine, and N-phenyldiethanolamine. The aforementioned chain extenders may be used alone or in combination. In the attached examples, the chain extender (B) is 1,4-butanediol.

[0059] Based on the total weight of the thermoplastic polyurethane precursor, the chain extender (B) may be present in an amount of 0.01 wt % to 30 wt %, such as 0.01 wt %, 0.05 wt %, 0.1 wt %, 0.5 wt %, 1 wt %, 2 wt %, 3 wt %, 4 wt %, 5 wt %, 6 wt %, 7 wt %, 8 wt %, 9 wt %, 10 wt %, 11 wt %, 12 wt %, 13 wt %, 14 wt %, 15 wt %, 16 wt %, 17 wt %, 18 wt %, 19 wt %, 20 wt %, 21 wt %, 22 wt %, 23 wt %, 24 wt %, 25 wt %, 26 wt %, 27 wt %, 28 wt %, 29 wt %, or 30 wt %, or in a range consisting of any two of the foregoing values.

[0060] 1.3. Polymer polyol (C)

[0061] The polyurethane precursor of the present invention uses a polymer polyol. The polymer polyol (C) can be selected from the following groups: polyether polyols, polyester polyols, polysiloxane polyols, and combinations thereof. Examples of polyether polyols include, but are not limited to, poly(alkylene ether) glycols, poly(tetramethylene ether glycol), polytetrahydrofuran diols, polyoxetane diols, and polypropylene oxide diols. Examples of polyester polyols include, but are not limited to, lactone polyester diols, polyesteramide diols, polyalkadiene diols (e.g., polybutadiene diol), polybutylene adipate, and polycarbonate diols. The aforementioned polymer polyols can be used alone or in combination. In the attached examples, the polymer polyol (C) is polytetrahydrofuran diol.

[0062] The molecular weight of the polymer polyol (C) may be 250 to 7000, for example, 250, 300, 350, 400, 450, 500, 550, 600, 650, 700, 750, 800, 850, 900, 950, 1000, 1100, 1200, 1300, 1400, 1500, 1600, 1700, 1800, 1900, 2000, 2100, 2200, 2300, 2400, 2500, 2600, 2700, 2800, 2900, 3000, 3100, 3200, 3300 6400, 6500, 6600, 6700, 6800, 6900, or 7000, or in the range consisting of any two of the above values.

[0063] Based on the total weight of the thermoplastic polyurethane precursor, the content of the polymer polyol (C) may be 0.01 wt % to 50 wt %, for example, 0.01 wt %, 0.05 wt %, 0.1 wt %, 0.5 wt %, 1 wt %, 2 wt %, 3 wt %, 4 wt %, 5 wt %, 6 wt %, 7 wt %, 8 wt %, 9 wt %, 10 wt %, 11 wt %, 12 wt %, 13 wt %, 14 wt %, 15 wt %, 16 wt %, 17 wt %, 18 wt %, 19 wt %, 20 wt %, 21 wt %, %, 22 weight %, 23 weight %, 24 weight %, 25 weight %, 26 weight %, 27 weight %, 28 weight %, 29 weight %, 30 weight %, 31 weight %, 32 weight %, 33 weight %, 34 weight %, 35 weight %, 36 weight %, 37 weight %, 38 weight %, 39 weight %, 40 weight %, 41 weight %, 42 weight %, 43 weight %, 44 weight %, 45 weight %, 46 weight %, 47 weight %, 48 weight %, 49 weight %, or 50 weight %, or within the range consisting of any two of the above values.

[0064] 1.4. First auxiliary agent (D)

[0065] The thermoplastic polyurethane precursor of the present invention comprises a first auxiliary agent (D) to improve the crystal point, chromaticity, yellowing resistance, thermal oxidation aging resistance and hydrolysis resistance of the obtained thermoplastic polyurethane. Specifically, the first auxiliary agent (D) comprises the following four components: (d1) a hindered phenol antioxidant, (d2) a liquid phosphite antioxidant, (d3) a lactone antioxidant, and (d4) at least one of a compound of formula (I) and a compound of formula (II), wherein R1 of formula (I) is a C12 alkenyl group.

[0066] [Formula (I)]

[0067]

[0068] [Formula (II)]

[0069]

[0070] 1.4.1.Ingredients (d1)

[0071] Component (d1) is a hindered phenol antioxidant, examples of which include phenylpropionic acid-3,5-di(1,1-dimethylethyl)-4-hydroxy-C7-C9 branched alkyl ester, di[3-(1,1-dimethylethyl)-4-hydroxy-5-methylphenylpropionic acid]triethylene glycol, pentaerythritol tetra(3,5-di-tert-butyl-4-hydroxy)phenylpropionic acid ester, 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid n-octadecyl ester, and 2,6-di-tert-butyl-p-methylphenol.

[0072] In a preferred embodiment of the present invention, component (d1) is phenylpropionic acid-3,5-di(1,1-dimethylethyl)-4-hydroxy-C7-C9 branched alkyl ester. Examples of phenylpropionic acid-3,5-di(1,1-dimethylethyl)-4-hydroxy-C7-C9 branched alkyl esters include phenylpropionic acid-3,5-di(1,1-dimethylethyl)-4-hydroxy-isoheptyl ester, phenylpropionic acid-3,5-di(1,1-dimethylethyl)-4-hydroxy-isooctyl ester, and phenylpropionic acid-3,5-di(1,1-dimethylethyl)-4-hydroxy-isononyl ester, such as the one available from QiTi Technology under the model BS-1135 product (CAS No.: 125643-61-0).

[0073] Based on the total weight of the thermoplastic polyurethane precursor, the content of component (d1) may be 0.01 wt % to 1.0 wt %, for example, 0.01 wt %, 0.02 wt %, 0.03 wt %, 0.04 wt %, 0.05 wt %, 0.06 wt %, 0.07 wt %, 0.08 wt %, 0.09 wt %, 0.1 wt %, 0.15 wt %, 0.2 wt %, 0.25 wt %, 0.3 wt %, 0.35 wt %, 0.4 wt %, 0.45 wt %, 0.5 wt %, 0.55 wt %, 0.6 wt %, 0.65 wt %, 0.7 wt %, 0.75 wt %, 0.8 wt %, 0.85 wt %, 0.9 wt %, 0.95 wt %, or 1.0 wt %, or within a range consisting of any two of the above values.

[0074] 1.4.2. Ingredients (d2)

[0075] Component (d2) is a liquid phosphite antioxidant, examples of which include phosphite mixed with 2,4-bis(1,1-dimethylpropyl)phenyl and 4-(1,1-dimethylpropyl)phenyl triester, tris(dipropylene glycol)phosphite, and poly(dipropylene glycol)phenyl phosphite. In a preferred embodiment of the present invention, component (d2) is a phosphorous acid mixed with 2,4-bis(1,1-dimethylpropyl)phenyl and 4-(1,1-dimethylpropyl)phenyl triester, which is a mixture of 2,4-bis(1,1-dimethylpropyl)phenyl-4-(1,1-dimethylpropyl)phenyl phosphite, 2,4-bis(1,1-dimethylpropyl)phenyl bis[4-(1,1-dimethylpropyl)phenyl]phosphite and tris[4-(1,1-dimethylpropyl)phenyl]phosphite, examples of which include the product commercially available from SI Group under the model 705T product (CAS No.: 939402-02-5).

[0076] Component (d2) may further include an acid neutralizer to provide acid absorption or hydrolysis inhibition functions. Examples of the acid neutralizer include, but are not limited to, triisopropanolamine (TIPA).

[0077] Based on the total weight of the thermoplastic polyurethane precursor, the content of component (d2) may be 0.01 wt % to 1.0 wt %, for example, 0.01 wt %, 0.02 wt %, 0.03 wt %, 0.04 wt %, 0.05 wt %, 0.06 wt %, 0.07 wt %, 0.08 wt %, 0.09 wt %, 0.1 wt %, 0.15 wt %, 0.2 wt %, 0.25 wt %, 0.3 wt %, 0.35 wt %, 0.4 wt %, 0.45 wt %, 0.5 wt %, 0.55 wt %, 0.6 wt %, 0.65 wt %, 0.7 wt %, 0.75 wt %, 0.8 wt %, 0.85 wt %, 0.9 wt %, 0.95 wt %, or 1.0 wt %, or within a range consisting of any two of the above values.

[0078] 1.4.3.Ingredients (d3)

[0079] Component (d3) is a lactone antioxidant, examples of which include 4-tert-butyl-2-(5-tert-butyl-2-oxy-3H-benzofuran-3-yl)phenyl-3,5-di-tert-butyl-4-hydroxybenzoate, 5,7-di-tert-butyl-3-(3,4-dimethylphenyl)benzofuran-2(3H)-one, and dimethylbenzene dibutylbenzofuranone.

[0080] In a preferred embodiment of the present invention, component (d3) is 4-tert-butyl-2-(5-tert-butyl-2-oxo-3H-benzofuran-3-yl)phenyl-3,5-di-tert-butyl-4-hydroxybenzoate, examples of which include the type available from QiTi Technology: 501 product (CAS No.: 1261240-30-5).

[0081] Based on the total weight of the thermoplastic polyurethane precursor, the content of component (d3) may be 0.01 wt % to 1.0 wt %, for example, 0.01 wt %, 0.02 wt %, 0.03 wt %, 0.04 wt %, 0.05 wt %, 0.06 wt %, 0.07 wt %, 0.08 wt %, 0.09 wt %, 0.1 wt %, 0.15 wt %, 0.2 wt %, 0.25 wt %, 0.3 wt %, 0.35 wt %, 0.4 wt %, 0.45 wt %, 0.5 wt %, 0.55 wt %, 0.6 wt %, 0.65 wt %, 0.7 wt %, 0.75 wt %, 0.8 wt %, 0.85 wt %, 0.9 wt %, 0.95 wt %, or 1.0 wt %, or within a range consisting of any two of the above values.

[0082] 1.4.4.Ingredients (d4)

[0083] Component (d4) comprises a compound of formula (I) or a compound of formula (II), or comprises both a compound of formula (I) and a compound of formula (II). Alternatively, component (d4) consists essentially of a compound of formula (I) or a compound of formula (II), or consists essentially of both a compound of formula (I) and a compound of formula (II). Alternatively, component (d4) consists of a compound of formula (I) or a compound of formula (II), or consists of both a compound of formula (I) and a compound of formula (II). R1 ​​in formula (I) is a C12 alkenyl group, which may be a straight-chain or branched alkenyl group, preferably a straight-chain alkenyl group.

[0084] [Formula (I)]

[0085]

[0086] [Formula (II)]

[0087]

[0088] The IUPAC name of the compound of formula (I) is 3-(3,5-di-tert-butyl-4-hydroxy-phenyl)-N-[3-[dodecenyl]-2,5-dioxo-pyrrolidin-1-yl]propionamide, wherein dodecenyl corresponds to R1 of formula (I) and can be a linear dodecenyl or a branched dodecenyl, preferably a linear dodecenyl. The IUPAC name of the compound of formula (II) is 3-(3,5-di-tert-butyl-4-hydroxy-phenyl)-N-[3-[1,3-dioxo-3a,4,7,7a-tetrahydroisoindol-2-yl]propionamide.

[0089] The compound of formula (I) and the compound of formula (II) can be obtained commercially or by chemical synthesis. The chemical synthesis method is not particularly limited. After the technical personnel in the technical field of the present invention have read the contents of the present specification, they can complete it according to the existing chemical synthesis mechanism. For example, the compound of formula (I) can be prepared by reacting 3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionyl hydrazide with dodecenyl succinic anhydride, and the compound of formula (II) can be prepared by reacting 3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionyl hydrazide with tetrahydrophthalic anhydride.

[0090] Based on the total weight of the thermoplastic polyurethane precursor, the content of component (d4) may be 0.01 wt % to 1.0 wt %, for example, 0.01 wt %, 0.02 wt %, 0.03 wt %, 0.04 wt %, 0.05 wt %, 0.06 wt %, 0.07 wt %, 0.08 wt %, 0.09 wt %, 0.1 wt %, 0.15 wt %, 0.2 wt %, 0.25 wt %, 0.3 wt %, 0.35 wt %, 0.4 wt %, 0.45 wt %, 0.5 wt %, 0.55 wt %, 0.6 wt %, 0.65 wt %, 0.7 wt %, 0.75 wt %, 0.8 wt %, 0.85 wt %, 0.9 wt %, 0.95 wt %, or 1.0 wt %, or within a range consisting of any two of the above values.

[0091] 1.5. Additives

[0092] The thermoplastic polyurethane precursor of the present invention may contain conventional additives that can be used for thermoplastic polyurethane as needed to adaptably improve the physicochemical properties of thermoplastic polyurethane or give the thermoplastic polyurethane desired functions. Examples of the existing additives include, but are not limited to, defoamers, leveling wetting agents, thickeners, dispersants, waxes, matting powders, antibacterial agents, metal oxide light shielding agents, light stabilizers, heat stabilizers, ultraviolet light absorbers, blue light absorbers, antioxidants, peroxide scavengers, free radical scavengers, fillers, rubbers (including silicone rubbers), food preservatives, flame retardants, plasticizers, dyes, pigments (including titanium dioxide, carbon black), brighteners, antistatic agents (including graphene, carbon nanotubes), fluorescent whitening agents, antioxidants, metal stabilizers, acid absorbers, and anti-hydrolysis agents. The aforementioned additives can be used alone or in combination.

[0093] The content of the additive is not particularly limited, as long as it can achieve its desired function. Generally speaking, based on the total weight of the thermoplastic polyurethane precursor, the content of the additive can be 0.01% to 30% by weight, such as 0.01%, 0.1%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, or 30% by weight, or within the range consisting of any two of the above values.

[0094] 2. Thermoplastic polyurethane

[0095] The thermoplastic polyurethane precursor of the present invention can be used to prepare thermoplastic polyurethane. Therefore, the present invention also provides a thermoplastic polyurethane, which contains a first auxiliary agent. The description and content of the first auxiliary agent are detailed in the section "1.4. First auxiliary agent (D)" and are not further described here.

[0096] The thermoplastic polyurethane of the present invention may also contain existing additives as needed to adaptably improve the physical and chemical properties of the thermoplastic polyurethane or to impart desired functions to the thermoplastic polyurethane. The description of existing additives that can be used in polyurethane is as described in the section "1.5. Additives" and is not further elaborated here.

[0097] 3. Preparation of thermoplastic polyurethane

[0098] The present invention also provides a method for preparing thermoplastic polyurethane, which comprises subjecting the thermoplastic polyurethane precursor of the present invention to polymerization to obtain thermoplastic polyurethane.

[0099] In some embodiments of the present invention, the polymerization reaction is carried out in the presence of a catalyst. Examples of the catalyst include, but are not limited to, tertiary amine catalysts, organometallic catalysts, and bases. Examples of tertiary amine catalysts include, but are not limited to, triethylamine, dimethylcyclohexylamine, triethylenediamine, N,N,N',N'-tetramethylethylenediamine, N-methylmorpholine, N,N-dimethylpiperazine, 2-(dimethylaminoethoxy)ethanol, diazabicyclo (2,2,2) octane, N,N-dimethylbenzylamine, and 2-methylimidazole. Examples of organometallic catalysts include, but are not limited to, tin diacetate, tin dioctoate, stannous octoate, stannous oleate, tin dilaurate, dibutyltin dilaurate, dibutyltin octoate, dioctyltin diacetate, ferric acetylacetonate, titanate, and titanium tetrabutoxide. Examples of bases include, but are not limited to, tetraalkylammonium hydroxide, sodium hydroxide, and sodium phenolate. The aforementioned catalysts can be used alone or in combination. In the accompanying examples, dibutyltin dilaurate was used as a catalyst.

[0100] The content of the catalyst is not particularly limited as long as it can promote the polymerization reaction. Generally speaking, based on the total weight of the thermoplastic polyurethane precursor, the content of the catalyst can be 0.01 wt % to 2.0 wt %, such as 0.01 wt %, 0.1 wt %, 0.5 wt %, 1 wt %, 1.5 wt %, or 2.0 wt %, or within a range consisting of any two of the above values.

[0101] 4. Application of thermoplastic polyurethane

[0102] The thermoplastic polyurethane of the present invention has at least the following advantages: low chroma, high yellowing resistance, high heat-oxidative aging resistance, high hydrolysis resistance, and especially low crystal point. Therefore, the present invention also provides a use of thermoplastic polyurethane in preparing thermoplastic polyurethane products with low chroma, high yellowing resistance, high heat-oxidative aging resistance, high hydrolysis resistance and low crystal point. The thermoplastic polyurethane products can be prepared by subjecting the thermoplastic polyurethane of the present invention to existing processing. The existing processing includes but is not limited to granulation, extrusion, lamination, injection molding, calendering, casting, film blowing, coating, melt-blowing, drawing, etc.

[0103] The types of the thermoplastic polyurethane products are not particularly limited, and may include any products to which existing thermoplastic polyurethanes can be applied, including but not limited to those selected from the following groups: transparent shells, packaging products, daily necessities, textiles, medical products, sports products, electronic products, optical products, construction products, mechanical parts, automotive products, military industrial products, and coatings. Examples of "packaging products" include films, examples of "daily necessities" include food containers, lamp parts, sheets, etc., examples of "textiles" include clothing, bedding, shoes, etc., examples of "medical products" include medical equipment components, examples of "electronic products" include display components, examples of "optical products" include solar panel components, examples of "construction products" include road construction components, wind power generation components, fireproof materials, waterproof materials, etc., examples of "mechanical parts" include agricultural machinery components, vehicle components, etc., examples of "automotive products" include airbags, and examples of "military industrial products" include explosion-proof panels.

[0104] Specifically, the thermoplastic polyurethane products include but are not limited to the following: packaging materials for oxygen-sensitive foods and medicines, air bags, balloons, air cushions, lampshades, cooking utensils, storage utensils, furniture, curtains, office floor mats, toys, sports equipment parts, balls, footwear parts, sports shoe air cushions, mountaineering shoes, snowshoes, golf shoes, skates, inflatable beds, drinking water bags, diving suits, snow suits, swimsuits, skis, raincoats, elastic bands, diapers, brand logos, golf-related products, eyeglass components, photochromic lenses, contact lens lenses, bed sheets, tablecloths, shower curtains, pianos, mobile phone keys, plastic inflatable toys, computer keyboards, umbrellas, suitcases, purses, plates, fibers, fabrics, clothes, pants, slimming clothes, outerwear covers, sanitary pants, aprons, furniture fabrics, gloves, medical devices, dental supplies, sterilization containers, filters, hygiene products, diapers, membranes, medical tubes, medical valves, hoses, hose liners, tubing, tube liners, protective clothing, wound dressings, surgical gowns, surgical caps, surgical gloves, hospital mattresses, ice packs, bandages, plasma bags, surgical dressings, masks, surgical bed bags, infusion bags, catheters, culture growth bottles, media bottles, instrument sampling windows, liquid storage containers (such as, for example, condoms, storage bags or bottles, infusion bags or bottles), aluminum plastic packaging, bubble packaging, biological implantable devices, pacemaker leads, artificial hearts, heart valves, stent covers, artificial tendons, artificial arteries, artificial veins, implants containing pharmaceutically active agents materials, drug delivery devices, vaginal rings, surgical correction products, implants, bone implants, mobile device housings, filters, optical lenses, optical elements, optical products, transparent screen films, conductive films, thermal transfer films, packaging films, low-resistance films, solar panel peripheral materials, lampshades, roof membranes, roof padding, eaves, wall materials, floor materials, pipeline materials, signs, sunshades, greenhouse covering films, backlights, windmill parts, wire covering materials, sound insulation materials, silencers, mechanical parts, adhesives, coatings, foam laminates, overmolded products, speaker drum paper, fireproof clothing, fire suits, fireproof cloth, awnings, waterproof strips, waterproof cloth, handles, handles, carpets, windows, window frame materials, doors, wallpaper, decorative panels, screens, Metal sheets, films, bearings, joints, valve components, conveyor belts, timing belts, gears, rubber materials, rollers, vehicle envelopes, vehicle shells, vehicle lamps, interior components, thermal insulation layers for transparent panels, sofa seats, insulation panels, tires, steering wheels, crates, casters, pulleys, airbag covers, buffers, radiators, fenders, instrument panels, door components, hood components, spoilers, wind deflectors, shell covers, reflector covers, body panels, protective side moldings, explosion-proof glass, boat and ship components, aircraft components, aircraft components, aircraft transparent parts, radar antenna covers, bullet-proof panels, explosion-proof glass, microwave absorbing layers, aircraft fuel tanks, weapons containment coatings, military water bags, life jackets, and inflatable boats.

[0105] 5. Examples

[0106] 5.1. Description of measurement method

[0107] The present invention is further illustrated by the following specific embodiments, wherein the measuring instruments and methods used are as follows:

[0108] [Melt flow index (MFI) measurement]

[0109] Prepare 5 grams of thermoplastic polyurethane as a test sample. According to ASTM D-1238, the initial MFI of the thermoplastic polyurethane is measured using a melt flow meter (model: GT-7100-MI, purchased from GOTECH) under the following conditions: temperature is 200°C, pressure is 5 kg, and the weight passing through a standard die (diameter 2.095 mm) in 10 minutes is measured. The unit of MFI is gram / 10 minutes (g / 10min).

[0110] [Thermal oxygen aging test]

[0111] Based on the aforementioned melt index measurement method, the thermoplastic polyurethane block is subjected to three additional melt index measurements, that is, the thermoplastic polyurethane block is melted three times in total to obtain the primary MFI, secondary MFI, and tertiary MFI of the thermoplastic polyurethane.

[0112] [Hue Detection]

[0113] According to ASTM 1926-70, a spectrophotometer (model: ColorQuest XE, purchased from Hunter Lab) was used to test the initial yellowness index (YI) of the thermoplastic polyurethane test piece.

[0114] [Color difference detection]

[0115] UV-Vis spectrophotometer (Varian 50, purchased from Agilent) was used to test the ΔE of the thermoplastic polyurethane test piece.

[0116] [Heat yellowing test]

[0117] The thermoplastic polyurethane test piece was placed in an oven at 120°C for aging, and the YI value and ΔE value of the thermoplastic polyurethane test piece were measured after aging for 16 hours, 24 hours, and 96 hours. The lower the value, the better the heat yellowing resistance.

[0118] [Hydrolysis resistance test]

[0119] First, prepare the sample and measure the tensile strength (initial tensile strength) of the thermoplastic polyurethane test piece just prepared using a tensile testing machine (model: AI-7000M, purchased from GOTECH) according to ASTM D-412. Next, put the thermoplastic polyurethane test piece into an oven at 95% humidity and 80°C for 168 hours. After that, measure the tensile strength (heat-resistant tensile strength) of the thermoplastic polyurethane test piece after being placed in the oven for 168 hours. The unit of tensile strength is kilogram force / square centimeter (kgf / cm 2 ). The tensile strength change rate (in %) is calculated according to the following formula, which represents the hydrolysis resistance of the thermoplastic polyurethane. The smaller the change rate, the better the hydrolysis resistance.

[0120]

[0121] [Crystal point test]

[0122] Thermoplastic polyurethane film was prepared in the following manner. First, the thermoplastic polyurethane block was cooled with liquid nitrogen to harden it, and then the thermoplastic polyurethane block was crushed into powder using a freeze grinder (model: UPZ100, purchased from Hosokawa Alpine) at -60°C and 22,000 rpm. After that, the thermoplastic polyurethane powder was placed in an oven at 100°C to remove moisture and dry. The dried thermoplastic polyurethane powder was placed in a small twin-screw extruder (model: MC 15HT, purchased from Xplore) for melt extrusion, wherein the screw speed was 15 rpm and the extruder temperature was 175°C to 180°C. Finally, a thermoplastic polyurethane film with a thickness of about 50 microns was obtained with a cooling wheel, and cut into test samples with a length of 5 cm and a width of 5 cm.

[0123] Use a 50x magnifying glass (model: PEAK 2008-50X STAND MICROSCOPE) to observe whether there are crystal points (grain-shaped or arrow-shaped spots) on the test sample of thermoplastic polyurethane film. Score from 1 to 5 based on the number of crystal points. The number of crystal points is the best, with a score of 5; the number of crystal points is the worst, with a score of 1.

[0124] 5.2. Preparation of thermoplastic polyurethane

[0125] [Example 1]

[0126] 100 g of polytetrahydrofuran diol (model: PTMEG1000, purchased from Mitsubishi Chemical, OH value 112.2), 11 g of 1,4-butanediol (purchased from Tokyo Chemical Industry), 0.1 wt% (based on the total weight of the thermoplastic polyurethane precursor) of hindered phenol antioxidant (model: BS-1135, purchased from QiTi Technology), 0.1 wt% (based on the total weight of the thermoplastic polyurethane precursor) of liquid phosphite antioxidant (model: 705T, purchased from SI Group International Group), 0.1 wt% (based on the total weight of the thermoplastic polyurethane precursor) of lactone antioxidant (model: Revenox501, purchased from QiTi Technology), 0.1 wt% (based on the total weight of the thermoplastic polyurethane precursor) of 3-(3,5-di-tert-butyl-4-hydroxy-phenyl)-N-[3-[dodecenyl]-2,5-dioxy-pyrrolidin-1-yl] propionamide, and 200 ppm of dibutyltin dilaurate were added to the reaction iron tank and heated to 110°C. 56 grams of MDI (purchased from BASF) was taken and preheated to 110°C, added to the reaction tank and stirred for 1 minute to react to obtain a rubber block. After that, the rubber block was placed in an oven and baked at 70°C for 24 hours for aging to obtain the thermoplastic polyurethane rubber block of Example 1.

[0127] [Example 2]

[0128] 100 g of polytetramethylene glycol PTMEG1000, 11 g of 1,4-butanediol, 0.1 wt % (based on the total weight of the thermoplastic polyurethane precursor) of hindered phenol antioxidant BS-1135, 0.1 wt% (based on the total weight of the thermoplastic polyurethane precursor) of liquid phosphite antioxidant 705T, 0.1 wt% (based on the total weight of the thermoplastic polyurethane precursor) of lactone antioxidant Revenox 501, 0.1 wt% (based on the total weight of the thermoplastic polyurethane precursor) of 3-(3,5-di-tert-butyl-4-hydroxy-phenyl)-N-[3-[1,3-dioxo-3a,4,7,7a-tetrahydroisoindol-2-yl]propionamide, and 200 ppm of dibutyltin dilaurate were added to the reaction iron tank and heated to 110°C. 56 g of MDI (purchased from BASF) was taken and preheated to 110°C, added to the reaction tank and stirred for 1 minute to react to obtain a rubber block. After that, the rubber block was placed in an oven and baked at 70°C for 24 hours to mature, and the thermoplastic polyurethane rubber block of Example 2 was obtained.

[0129] [Comparative Example 1]

[0130] 100 g of polytetramethylene glycol PTMEG1000, 11 g of 1,4-butanediol, 0.4 wt % (based on the total weight of the thermoplastic polyurethane precursor) of hindered phenol antioxidant BS-1135 and 200 ppm of dibutyltin dilaurate were added to a reaction iron tank and heated to 110°C. 56 g of MDI (purchased from BASF) was preheated to 110°C, added to the reaction tank and stirred for 1 minute to react to obtain a rubber block. After that, the rubber block was placed in an oven and baked at 70°C for 24 hours to mature, thereby obtaining a thermoplastic polyurethane rubber block of Comparative Example 1.

[0131] [Comparative Example 2]

[0132] 100 g of polytetrahydrofuran diol PTMEG1000, 11 g of 1,4-butanediol, 0.4 wt % (based on the total weight of the thermoplastic polyurethane precursor) of liquid phosphite antioxidant 705T and 200 ppm of dibutyltin dilaurate were added to the reaction iron tank and heated to 110°C. 56 g of MDI (purchased from BASF) was taken and preheated to 110°C, added to the reaction tank and stirred for 1 minute to react to obtain a rubber block. After that, the rubber block was placed in an oven and baked at 70°C for 24 hours to mature, obtaining the thermoplastic polyurethane rubber block of Comparative Example 2.

[0133] [Comparative Example 3]

[0134] 100 g of polytetrahydrofuran diol PTMEG1000, 11 g of 1,4-butanediol, 0.4 wt% (based on the total weight of the thermoplastic polyurethane precursor) of lactone antioxidant Revenox 501, and 200 ppm of dibutyltin dilaurate were added to a reaction iron tank and heated to 110° C. 56 g of MDI (purchased from BASF) was preheated to 110° C., added to the reaction tank and stirred for 1 minute to react to obtain a rubber block. After that, the rubber block was placed in an oven and baked at 70° C. for 24 hours to mature, to obtain a thermoplastic polyurethane rubber block of Comparative Example 3.

[0135] [Comparative Example 4]

[0136] 100 g of polytetrahydrofuran diol PTMEG1000, 11 g of 1,4-butanediol, 0.4 wt% (based on the total weight of the thermoplastic polyurethane precursor) of 3-(3,5-di-tert-butyl-4-hydroxy-phenyl)-N-[3-[dodecenyl]-2,5-dioxy-pyrrolidin-1-yl] propionamide, and 200 ppm of dibutyltin dilaurate were added to a reaction iron tank and heated to 110° C. 56 g of MDI (purchased from BASF) was preheated to 110° C., added to the reaction tank and stirred for 1 minute to react to obtain a rubber block. After that, the rubber block was placed in an oven and baked at 70° C. for 24 hours to mature, to obtain the thermoplastic polyurethane rubber block of Comparative Example 4.

[0137] [Comparative Example 5]

[0138] 100 g of polytetramethylene glycol PTMEG1000, 11 g of 1,4-butanediol, 0.2 wt % (based on the total weight of the thermoplastic polyurethane precursor) of hindered phenol antioxidant BS-1135, 0.2 wt% (based on the total weight of the thermoplastic polyurethane precursor) of liquid phosphite antioxidant 705T and 200 ppm of dibutyltin dilaurate were added to the reaction iron tank and heated to 110°C. 56 g of MDI (purchased from BASF) was taken and preheated to 110°C, added to the reaction tank and stirred for 1 minute to react to obtain a rubber block. After that, the rubber block was placed in an oven and baked at 70°C for 24 hours to mature, to obtain the thermoplastic polyurethane rubber block of Comparative Example 5.

[0139] [Comparative Example 6]

[0140] 100 g of polytetramethylene glycol PTMEG1000, 11 g of 1,4-butanediol, 0.2 wt % (based on the total weight of the thermoplastic polyurethane precursor) of hindered phenol antioxidant BS-1135, 0.1 wt% (based on the total weight of the thermoplastic polyurethane precursor) of liquid phosphite antioxidant 705T, 0.1 wt% (based on the total weight of the thermoplastic polyurethane precursor) of lactone antioxidant Revenox 501, and 200 ppm of dibutyltin dilaurate were added to a reaction iron pot and heated to 110°C. 56 g of MDI (purchased from BASF) was taken and preheated to 110°C, added to the reaction pot and stirred for 1 minute to react to obtain a rubber block. After that, the rubber block was placed in an oven and baked at 70°C for 24 hours to mature, obtaining the thermoplastic polyurethane rubber block of Comparative Example 1.

[0141] 5.3. Testing of thermoplastic polyurethane

[0142] Thermoplastic polyurethane rubber blocks of Examples 1 and 2 and Comparative Examples 1 to 6 were used to prepare thermoplastic polyurethane test sheets. First, 55 g of the thermoplastic polyurethane rubber block was placed in an oven at 100° C. for 2 hours to remove surface moisture and fully dry. Next, the thermoplastic polyurethane rubber block was placed in a 20 cm×15 cm×0.15 cm mold and thermoformed at 190° C. for 1.5 minutes using a thermoforming machine (purchased from Longchang Company) at a pressure of 20 kg / cm2. The thermoplastic polyurethane molded by thermoforming was then placed in a cold press and cooled at a pressure of 50 kg / cm2 for 5 to 10 minutes to obtain a thermoplastic polyurethane test sheet with a thickness of 0.15 cm.

[0143] The MFI, YI and ΔE of the thermoplastic polyurethanes of Examples 1 and 2 and Comparative Examples 1 to 6 were measured by the aforementioned method, and thermal oxygen aging resistance test, thermal yellowing resistance test, hydrolysis resistance test and crystal point test were performed, and the results are recorded in Tables 1 to 5.

[0144] Table 1: MFI and thermal oxygen aging resistance test of thermoplastic polyurethanes of Examples 1 and 2 and Comparative Examples 1 to 6

[0145] Initial MFI One-time MFI Secondary MFI Three-time MFI unit g / 10 min g / 10 min g / 10 min g / 10 min Example 1 1.8 2.8 5.6 8.5 Example 2 2.1 3.1 9.1 13.4 Comparative Example 1 3.0 3.4 11.8 18.6 Comparative Example 2 5.1 5.2 8.6 13.2 Comparative Example 3 5.4 6.4 20.6 31.17 Comparative Example 4 4.5 6.8 30.0 38.6 Comparative Example 5 4.4 5.4 20.0 29.2 Comparative Example 6 3.3 3.4 12.0 19.2

[0146] Table 2: YI, ΔE and heat yellowing resistance test of thermoplastic polyurethane of Example 1 and Comparative Examples 1 to 6

[0147] Initial YI ΔYI after 16 hours ΔE after 16 hours Example 1 2.1 4.6 2.9 Comparative Example 1 2.9 10.1 6.5 Comparative Example 2 1.2 4.1 2.6 Comparative Example 3 2.6 10.5 6.7 Comparative Example 4 1.7 7.5 4.4 Comparative Example 5 2.2 5.9 3.8 Comparative Example 6 2.2 6.6 4.2

[0148] Table 3: Hydrolysis resistance test of thermoplastic polyurethanes of Examples 1 and 2 and Comparative Examples 1 to 6

[0149]

[0150]

[0151] Table 4: Crystal point test of thermoplastic polyurethane of Examples 1 and 2 and Comparative Examples 1 to 6

[0152]

[0153] Table 5: Long-term heat-resistant yellowing test of Examples 1 and 2 and Comparative Example 6

[0154] Example 1 Example 2 Comparative Example 6 Initial YI 2.1 1.5 2.2 ΔYI after 96 hours 23.4 19.2 37.1 ΔE after 96 hours 15.1 12.4 23.5

[0155] As shown in Tables 1 to 5, the thermoplastic polyurethane prepared by the thermoplastic polyurethane precursor of the present invention can simultaneously have the advantages of low initial chromaticity, high yellowing resistance, high heat-oxidative aging resistance, high hydrolysis resistance and low crystal point, especially the crystal point test result is excellent. In contrast, the thermoplastic polyurethane not prepared by the thermoplastic polyurethane precursor of the present invention cannot simultaneously have low initial chromaticity, high yellowing resistance, high heat-oxidative aging resistance, and high hydrolysis resistance, especially the crystal point test result is not good. Specifically, as shown in Comparative Example 1, when the thermoplastic polyurethane precursor only contains hindered phenol antioxidants as the first auxiliary agent, the obtained thermoplastic polyurethane has poor initial chromaticity, poor heat yellowing resistance, poor heat-oxidative aging resistance and poor crystal point test results. As shown in Comparative Example 2, when the thermoplastic polyurethane precursor only contains liquid phosphite antioxidants as the first auxiliary agent, the obtained thermoplastic polyurethane has poor hydrolysis resistance and poor crystal point test results. As shown in Comparative Example 3, when the thermoplastic polyurethane precursor only contains a lactone antioxidant as the first auxiliary agent, the obtained thermoplastic polyurethane has poor heat yellowing resistance, poor heat oxygen aging resistance, poor hydrolysis resistance, and poor crystal point test results. As shown in Comparative Example 4, when the thermoplastic polyurethane precursor only contains the compound of formula (I) as the first auxiliary agent, the obtained thermoplastic polyurethane has poor heat yellowing resistance, poor heat oxygen aging resistance, and poor crystal point test results. As shown in Comparative Example 5, when the thermoplastic polyurethane precursor only contains a hindered phenol antioxidant and a liquid phosphite antioxidant as the first auxiliary agent, the obtained thermoplastic polyurethane has poor heat oxygen aging resistance, poor hydrolysis resistance, and poor crystal point test results. As shown in Comparative Example 6, when the thermoplastic polyurethane precursor only contains hindered phenol antioxidants, liquid phosphite antioxidants and lactone antioxidants as the first auxiliary agent but does not contain the compound of formula (I) or the compound of formula (II), the obtained thermoplastic polyurethane has poor heat-oxidative aging resistance, poor hydrolysis resistance and poor crystal point test results.

[0156] In order to more intuitively present the technical effects of the present invention, Example 1 is used as a judgment basis to compare and grade the examples and comparative examples in terms of initial chromaticity, yellowing resistance, heat-oxidative aging resistance, hydrolysis resistance and crystal point performance. The evaluation criteria are: ◎ is excellent, ○ is good, △ is ordinary, and × is poor. The comparison results are shown in Table 6. The thermoplastic polyurethane of the present invention can simultaneously have excellent performance in low initial chromaticity, high yellowing resistance, high heat-oxidative aging resistance, high hydrolysis resistance and low crystal point.

[0157] Table 6: Comprehensive comparison of Examples 1 and 2 and Comparative Examples 1 to 6

[0158]

[0159] The above embodiments are only used to illustrate the principle and efficacy of the present invention and to describe the technical features of the present invention, and are not intended to limit the scope of protection of the present invention. Any changes or arrangements that can be easily completed by a person familiar with the present technology without violating the technical principle of the present invention are within the scope of the present invention.

Claims

1. A thermoplastic polyurethane precursor, characterized in that: Include: (A) polyisocyanate; (B) a chain extender; (C) polymer polyols; and (D) a first auxiliary agent, comprising: (d1) phenylpropionic acid-3,5-bis(1,1-dimethylethyl)-4-hydroxy-C7-C9 branched alkyl ester; (d2) Phosphorous acid mixed with 2,4-bis(1,1-dimethylpropyl)phenyl and 4-(1,1-dimethylpropyl)phenyl triester; (d3) 4-tert-butyl-2-(5-tert-butyl-2-oxo-3H-benzofuran-3-yl)phenyl-3,5-di-tert-butyl-4-hydroxybenzoate; and (d4) at least one of a compound of formula (I) and a compound of formula (II), [Formula (I)] Wherein R1 is C12 alkenyl; [Formula (II)] 2. The thermoplastic polyurethane precursor according to claim 1, characterized in that The polyisocyanate (A) contains an aromatic polyisocyanate.

3. The thermoplastic polyurethane precursor according to claim 1, characterized in that The polymer polyol (C) is selected from the group consisting of polyether polyol, polyester polyol, polysiloxane polyol, and combinations thereof.

4. The thermoplastic polyurethane precursor according to claim 1, characterized in that The chain extender (B) is selected from the group consisting of polyols, diamines, amino alcohols, and combinations thereof.

5. The thermoplastic polyurethane precursor according to any one of claims 1 to 4, characterized in that Based on the total weight of the thermoplastic polyurethane precursor, the content of the components (d1) to (d4) is independently 0.01 wt % to 1.0 wt %.

6. The thermoplastic polyurethane precursor according to any one of claims 1 to 4, characterized in that The invention comprises additives selected from the following groups: defoaming agent, leveling wetting agent, thickener, dispersant, wax, matting powder, antibacterial agent, metal oxide light shielding agent, light stabilizer, heat stabilizer, ultraviolet light absorber, blue light absorber, antioxidant, peroxide scavenger, free radical scavenger, filler, rubber, food preservative, flame retardant, plasticizer, dye, pigment, brightener, antistatic agent, fluorescent whitening agent, antioxidant, metal stabilizer, acid absorber, anti-hydrolysis agent and combinations thereof.

7. A thermoplastic polyurethane comprising a first auxiliary agent, characterized in that: The first auxiliary agent comprises: (d1) phenylpropionic acid-3,5-bis(1,1-dimethylethyl)-4-hydroxy-C7-C9 branched alkyl ester; (d2) phosphorous acid mixed with 2,4-bis(1,1-dimethylpropyl)phenyl and 4-(1,1-dimethylpropyl)phenyl triester; (d3) 4-(1,1-dimethylethyl)-2-[5-(1,1-dimethylethyl)-2,3-hydrogen-2-oxo-3-benzofuran]phenyl-3,5-bis(1,1-dimethylethyl)-4-hydroxybenzoate; and (d4) at least one of a compound of formula (I) and a compound of formula (II), [Formula (I)] Wherein R1 is C12 alkenyl; [Formula (II)] 8. The thermoplastic polyurethane according to claim 7, characterized in that The invention comprises additives selected from the following groups: defoaming agent, leveling wetting agent, thickener, dispersant, wax, matting powder, antibacterial agent, metal oxide light shielding agent, light stabilizer, heat stabilizer, ultraviolet light absorber, blue light absorber, antioxidant, peroxide scavenger, free radical scavenger, filler, rubber, food preservative, flame retardant, plasticizer, dye, pigment, brightener, antistatic agent, fluorescent whitening agent, antioxidant, metal stabilizer, acid absorber, anti-hydrolysis agent and combinations thereof.

9. A method for preparing thermoplastic polyurethane, characterized in that: The following steps are involved: Providing a thermoplastic polyurethane precursor as claimed in any one of claims 1 to 6; and The thermoplastic polyurethane precursor is subjected to a polymerization reaction to obtain a thermoplastic polyurethane.

10. The method according to claim 9, characterized in that The method comprises granulating, extruding, laminating, injection molding, calendering, casting, film blowing, coating, melt-blowing or drawing processing on the thermoplastic polyurethane.

11. Use of the thermoplastic polyurethane as claimed in claim 7 or 8 in the preparation of thermoplastic polyurethane products with low crystallinity, low chroma, high yellowing resistance, high heat-oxidative aging resistance, and high hydrolysis resistance.

12. The use according to claim 11, characterized in that The thermoplastic polyurethane product is selected from the following groups: transparent housing, packaging products, daily necessities, textiles, medical products, sports products, electronic products, optical products, building products, mechanical parts, automotive products, military industrial products, and coatings.

Images