Modified toluene diisocynate composition as well as preparation method and application thereof

Abstract

The invention discloses a modified toluene diisocynate composition as well as a preparation method and application thereof. The modified toluene diisocynate composition comprises 9-20 wt% of a compound containing a carbamate group, 20-25 wt% of a compound containing a biuret group and 25-30 wt% of a compound containing a triuret group and a polyuret group. The content of isocyanate groups in the modified toluene diisocynate composition is 29.0-33.0%, and the modified toluene diisocynate composition has the viscosity of 500-15000mPa. S at the temperature of 25 DEG C, can replace PMDI and is applied to the field of high-resilience polyurethane foaming.

Description

Technical Field

[0001] The present invention belongs to the technical field of polyurethane, and relates to a modified toluene diisocyanate (modified TDI) composition that can replace PMDI (polymethylene polyphenyl polyisocyanate) and a preparation method thereof. In particular, it relates to a modified toluene diisocyanate composition containing a carbamate group and a biuret group, a triuret group, a polyuret group and the like and a preparation method thereof, which can be used for the preparation of high-resilience polyurethane foam. Background Art

[0002] PMDI is a mixture of polyisocyanates with different functionalities and MDI (dimethylphenyl diisocyanate), with a viscosity of about 100-800mPa·s (25°C), such as Wanhua Chemical's WANNATE PM-200, WANNATE PM-400, WANNATE PM-700, etc. It is an important raw material for the production of polyurethane soft foam, semi-rigid foam, and rigid foam, and is widely used in refrigerator insulation, cold chain transportation, automotive interiors, furniture, rail transportation, construction and other fields.

[0003] The main raw materials of high-resilience polyurethane foam include modified isocyanate and combined polyether polyols. Modified isocyanate mainly includes MDI system (MDI-100, MDI-50, PMDI, liquefied MDI, urethane modified MDI or its mixture), TM system (mixture of PMDI, TDI, etc.). Among them, the foam density of TM system is low and the physical properties are good (tensile strength, elongation at break, tear strength, rebound rate), which is widely used in the automotive seat industry. The foam made by TDI has low density and good performance, but the foam hardness is low and the curing time is long, while the foam made by PMDI has high hardness and short curing time, but the physical properties are not good.

[0004] The foam made by mixing TDI and PMDI in a certain proportion can have the advantages of both. In the common TM system on the market, the content of PMDI is 20-60%, the content of TDI is 80%-40%, the NCO is 38.0-45.0%, and the viscosity is 10-40mPa·s (25℃). The viscosity of the combined polyether polyol is 1000-3500mPa·s (25℃). When two raw materials with large viscosity differences are mixed and foamed in a specific weight ratio, the precision requirements of the polyurethane high-pressure foaming equipment are high, and problems such as poor mixing and uneven hardness of foam products often occur, especially for TM products with higher TDI content and lower viscosity. In addition, in recent years, the price of TDI is generally lower than that of PMDI, and the replacement of PMDI by modified TDI has cost advantages.

[0005] CN 108026247 B discloses a polyurethane prepolymer with an overall NCO content of less than 7% generated by the reaction of TDI biuret with a 40% NCO content and PMDI or other isocyanates and polyols, which has a viscosity of less than about 10,000 mPa·s at 50°C and is used to reduce the mist-like polyurethane foam in the fields of sealing and insulation. The prepolymer disclosed in the patent does not use water in the reaction, the PMDI and NCO contents are relatively small, the viscosity is uncontrollable, and the plasticizer etc. will play a defoaming role to form collapsed bubbles, which is not suitable for high-resilience polyurethane foaming systems.

[0006] Therefore, it is necessary to provide a modified toluene diisocyanate that can replace PMDI at a significantly lower cost without sacrificing foam performance, can produce lower density products, and has a viscosity in the range of 500-15000 mPa·s to ensure good mixing with the combined polyol, thereby effectively improving the quality of the foam product. Summary of the invention

[0007] In order to solve the problems existing in the prior art, the present invention provides a modified toluene diisocyanate (modified TDI) composition, which comprises a carbamate group and a biuret group, a triuret group, a polyuret group and other structures, and can replace PMDI and be used in a high-resilience polyurethane foam system. Compared with PMDI, the modified TDI composition provided by the present invention has a higher foaming ratio, the density of the product produced can be reduced by 5-10%, the viscosity is increased and controllable within the range of 500-15000mPa·s, thereby significantly improving the miscibility with the combined polyether polyol, and greatly reducing the cost.

[0008] At the same time, the present invention provides a preparation method of the modified TDI composition, which provides a flexible segment through carbamate-based modification, giving the product excellent compression deformation, rebound and comfort, and provides a rigid segment through structural modifications such as biuret, triuret, and polyuret, giving the product low density, high hardness, high viscosity, and high flame retardant properties.

[0009] The present invention also provides the application of the modified TDI composition, which can be used as a substitute for PMDI for the preparation of high-resilience polyurethane foam.

[0010] To achieve the above purpose, the technical solution of the present invention is as follows:

[0011] In a first aspect, the present invention provides a modified toluene diisocyanate composition, which comprises 9-20 wt % of a compound containing a carbamate group, 20-25 wt % of a compound containing a biuret group, and 25-30 wt % of a compound containing a triuret group and a polyuret group.

[0012] The modified toluene diisocyanate composition of the present invention further comprises unmodified toluene diisocyanate, wherein the sum of the mass percentages of the unmodified toluene diisocyanate and the compounds containing carbamate groups, the compounds containing biuret groups, and the compounds containing triuret groups and polyuret groups is 100%.

[0013] Specifically, the content of the compound containing a carbamate group includes but is not limited to 9wt%, 10wt%, 11wt%, 12wt%, 13wt%, 14wt%, 15wt%, 16wt%, 17wt%, 18wt%, 19wt%, 20wt% or a range between any two thereof; the content of the compound containing a biuret group includes but is not limited to 20wt%, 20.5wt%, 21wt%, 21.5wt%, 22wt%, 22 .5wt%, 23wt%, 23.5wt%, 24wt%, 24.5wt%, 25wt% or the range composed of any two thereof; the content of the compound containing triuret group and polyuret group includes but is not limited to 25wt%, 25.5wt%, 26wt%, 26.5wt%, 27wt%, 27.5wt%, 28wt%, 28.5wt%, 29wt%, 29.5wt%, 30wt% or the range composed of any two thereof.

[0014] The modified toluene diisocyanate composition of the present invention contains carbamate, biuret, triuret and polyuret structures, wherein the carbamate modified chain segment provides a flexible chain segment, while the biuret, triuret, polyuret and other group modified chain segments provide a rigid chain segment, and the combination of the two can prepare a foam with high resilience and good comfort, and at the same time has the characteristics of high hardness and good support.

[0015] In one embodiment, the modified toluene diisocyanate composition has an isocyanate group (NCO) content of 29.0-33.0%, including but not limited to 29%, 29.5%, 30%, 30.5%, 31%, 31.5%, 32%, 32.5%, 33% or any range between two thereof. When the NCO content is lower than 29.0%, the polyurethane foam prepared therefrom has a high density. When the NCO content is higher than 33.0%, due to the low content of biuret, triuret, polyuret and other groups, the foaming process is prone to collapse and the tolerance becomes poor.

[0016] In one embodiment, the modified toluene diisocyanate composition has a viscosity of 500-15000 mPa·s at 25° C., including but not limited to 500 mPa·s, 800 mPa·s, 1000 mPa·s, 2000 mPa·s, 3000 mPa·s, 4000 mPa·s, 5000 mPa·s, 6000 mPa·s, 7000 mPa·s, 8000 mPa·s, 9000 mPa·s, 10000 mPa·s, 11000 mPa·s, 12000 mPa·s, 13000 mPa·s, 14000 mPa·s, 15000 mPa·s or a range between any two thereof. When the viscosity of the modified TDI is lower than 500 mPa·s, it is greatly different from the viscosity of the combined polyether, and poor mixing is likely to occur, affecting the production qualification rate of the foam. When the viscosity is greater than 15000 mPa·s, the fluidity is poor, which is not conducive to the formation of foam in subsequent applications.

[0017] The modified toluene diisocyanate composition of the present invention can be prepared by using known raw materials and conventional reaction processes in the art, for example, by reacting toluene diisocyanate with polyether polyol and water under the action of a catalyst;

[0018] Specifically, the modified toluene diisocyanate composition is obtained by reacting raw materials including the following components:

[0019] (A) toluene diisocyanate;

[0020] (B) polyether polyol;

[0021] (C) a metal compound catalyst;

[0022] (D) Water;

[0023] (E) Inhibitor.

[0024] In some specific examples, the amount of the polyether polyol added is 10-20% of the mass of toluene diisocyanate, including but not limited to 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 29% or a range composed of any two thereof; and / or

[0025] The amount of water added is 1.9-2.4% of the mass of toluene diisocyanate, including but not limited to 1.9%, 1.95%, 2%, 2.05%, 2.1%, 2.15%, 2.2%, 2.25%, 2.3%, 2.35%, 2.4% or any range therebetween; and / or

[0026] The amount of the metal compound catalyst added is 10-20 ppm of the mass of toluene diisocyanate, including but not limited to 10 ppm, 11 ppm, 12 ppm, 13 ppm, 14 ppm, 15 ppm, 16 ppm, 17 ppm, 18 ppm, 19 ppm, 20 ppm or a range between any two thereof; and / or

[0027] The addition amount of the inhibitor is 20-50ppm of the mass of toluene diisocyanate, including but not limited to 20ppm, 22ppm, 25ppm, 28ppm, 30ppm, 32ppm, 35ppm, 38ppm, 40ppm, 42ppm, 45ppm, 48ppm, 50ppm or the range composed of any two thereof.

[0028] In some specific examples, the toluene diisocyanate of component (A) has an isocyanate group (NCO) content of 48.0-48.5wt%, including but not limited to 48wt%, 48.1wt%, 48.2wt%, 48.3wt%, 48.4wt%, 48.5wt% or a range composed of any two thereof; and / or

[0029] The toluene diisocyanate of component (A) is one or a mixture of 2,6-toluene diisocyanate and 2,4-toluene diisocyanate;

[0030] Preferably, the toluene diisocyanate comprises 0-40wt% of 2,6-toluene diisocyanate and 60-100wt% of 2,4-toluene diisocyanate, wherein the sum of the mass percentages of 2,6-toluene diisocyanate and 2,4-toluene diisocyanate is 100wt%; specifically, the content of 2,6-toluene diisocyanate includes but is not limited to 0wt%, 5wt%, 15wt%, 20wt%, 25wt%, 30wt%, 35wt%, 40wt% or a range composed of any two thereof;

[0031] More preferably, the toluene diisocyanate comprises 20-40 wt % of 2,6-toluene diisocyanate and 60-80 wt % of 2,4-toluene diisocyanate, wherein the sum of the mass percentages of 2,6-toluene diisocyanate and 2,4-toluene diisocyanate is 100 wt %.

[0032] In some specific examples, the polyether polyol of component (B) includes but is not limited to one or more of petroleum-based polyether polyol and bio-based polyether polyol;

[0033] Preferably, the polyether polyol is selected from one or more polyether polyols having an average functionality of 3 and a hydroxyl value of 25-40 mgKOH / g.

[0034] In some specific examples, the metal compound catalyst of component (C) refers to a substance that can catalyze the reaction of isocyanate groups with polyether polyols to form carbamate groups under certain conditions, and simultaneously catalyze the reaction of isocyanate groups with water to form urea structures, and on this basis, continue to react with water and isocyanate groups to form substances containing biuret, triuret and polyuret structures;

[0035] Preferably, the metal compound catalyst includes but is not limited to an inorganic metal catalyst and an organic metal catalyst, preferably one or more of potassium hydroxide, sodium hydroxide, sodium sulfate, potassium sulfate, potassium sulfite, sodium sulfite, sodium bisulfite, sodium carbonate, sodium bicarbonate, sodium dodecylbenzene sulfonate, and sodium dodecyl sulfate, more preferably one or more of potassium hydroxide, sodium hydroxide, sodium carbonate, sodium bisulfite, sodium dodecylbenzene sulfonate, and sodium dodecyl sulfate, further preferably one or more of potassium hydroxide, sodium hydroxide, and sodium dodecylbenzene sulfonate.

[0036] In some specific examples, the polymerization inhibitor of component (E) refers to a substance that can block the reaction of urea, water and isocyanate groups to form biuret, triuret and polyuret structures under certain conditions;

[0037] Preferably, the polymerization inhibitor is selected from one or more of acyl chlorides, phenols and dimethyl ester compounds, preferably one or more of benzoyl chloride, adipoyl chloride, phosphoric acid, dimethyl sulfate, resorcinol and hydroquinone.

[0038] In a second aspect, the present invention provides a method for preparing the modified toluene diisocyanate composition, which can be prepared by conventional reaction processes in the art, for example, by reacting toluene diisocyanate with polyether polyol and water in the presence of a catalyst.

[0039] A method for preparing a modified toluene diisocyanate composition comprises the following steps:

[0040] S1: a prepolymer is formed by the reaction of toluene diisocyanate and polyether polyol;

[0041] S2: adding a metal compound catalyst and water to the prepolymer to carry out a first-stage reaction, and then raising the temperature to carry out a second-stage reaction;

[0042] S3: Add an inhibitor and continue the reaction until the desired viscosity is reached to obtain modified toluene diisocyanate.

[0043] For the preparation method of the present invention, reference can be made to the raw material selection and dosage range listed above. For other related operations and process conditions, and the devices used therein, corresponding conventional selections in the art can be adopted. There is no particular limitation to this. The technicians can optimize the known processes in the prior art according to actual needs. Specifically, for example, the conditions listed in the following embodiments of the present invention can be adopted:

[0044] In some specific examples, the reaction in step S1 has a temperature of 60-80°C and a time of 0.5-1h; specifically, the temperature includes but is not limited to 60°C, 62°C, 65°C, 68°C, 70°C, 72°C, 75°C, 78°C, 80°C or a range between any two of them, and the time includes but is not limited to 0.5h, 0.6h, 0.7h, 0.8h, 0.9h, 1h or a range between any two of them.

[0045] In some specific examples, in step S2, the first stage reaction has a temperature of 60-80°C and a time of 10-15 min; specifically, the temperature includes but is not limited to 60°C, 62°C, 65°C, 68°C, 70°C, 72°C, 75°C, 78°C, 80°C or a range between any two thereof, and the time includes but is not limited to 10 min, 11 min, 12 min, 13 min, 14 min, 15 min or a range between any two thereof; and / or

[0046] The second stage reaction has a temperature of 110-140°C and a time of 1-6h; specifically, the temperature includes but is not limited to 110°C, 115°C, 120°C, 125°C, 130°C, 135°C, 140°C or a range between any two thereof, and the time includes but is not limited to 1h, 2h, 3h, 4h, 5h, 6h or a range between any two thereof.

[0047] In some specific examples, the reaction in step S3 has a temperature of 110-140°C and a time of 10-30 min; specifically, the temperature includes but is not limited to 110°C, 115°C, 120°C, 125°C, 130°C, 135°C, 140°C or a range between any two of them, and the time includes but is not limited to 10 min, 12 min, 15 min, 18 min, 20 minn, 22 min, 25 min, 28 min, 30 min or a range between any two of them.

[0048] In the preparation method of the present invention, after the reaction of toluene diisocyanate and polyether polyol is completed, water is added to the prepolymer, and the isocyanate group is reacted with water under the action of a catalyst to generate a urea structure. During the reaction, a large amount of gas will be produced in the system, and the system is converted from a colorless transparent liquid to a white or light white liquid. Subsequently, the temperature is increased, and the modified toluene diisocyanate containing structures such as biuret, triuret and polyuret is continuously reacted with water at high temperature to form a yellow or light yellow transparent liquid. In this process, the temperature can be adjusted within a certain range to promote the reaction of NCO with urea, shorten the reaction time, and increase the viscosity of the system. Finally, a suitable amount of inhibitor is added to terminate the reaction to obtain a modified toluene diisocyanate composition of the desired viscosity.

[0049] In a third aspect, the present invention also provides an application of the modified toluene diisocyanate composition.

[0050] In one embodiment, the present invention provides the use of the modified toluene diisocyanate composition as a PMDI substitute. Compared with PMDI, the modified TDI composition provided by the present invention has a higher foaming ratio, the density of the produced product can be reduced by 5-10%, the viscosity is increased and controllable within the range of 500-15000 mPa·s, thereby significantly improving the miscibility with the combined polyether polyol and significantly reducing the cost.

[0051] In one embodiment, the present invention provides the use of the modified toluene diisocyanate composition in high resilience polyurethane foam. The modified TDI composition provided by the present invention provides a flexible segment through urethane group modification, giving the product excellent compression deformation, resilience and comfort, and provides a rigid segment through biuret, triuret, polyuret and other group structure modification, giving the product low density, high viscosity, high flame retardant properties.

[0052] Compared with the prior art, the present invention has the following beneficial effects:

[0053] The present invention provides a modified TDI composition with a viscosity of 500-15000 mPa·s (25° C.) and an NCO content of 29.0-33.0%, which can replace PMDI in the TM system on the market, and can be prepared into an isocyanate product for the production of high-resilience polyurethane foam. Compared with the TM system products on the market, the product using the modified TDI composition has a higher foaming ratio and can produce a lower density product. At the same time, the product using the modified TDI composition has a property close to the viscosity of the combined polyether polyol, has good miscibility with the combined polyether polyol, and the prepared foam has good mechanical properties. At the same time, it has the advantage of low cost and can be used for the manufacture of parts such as automobile seats. DETAILED DESCRIPTION

[0054] In order to better understand the technical solution of the present invention, the following are specific embodiments of the present invention, and the technical solution of the present invention is further described in conjunction with the embodiments, but the present invention is not limited to these embodiments.

[0055] In the examples and comparative examples of the present invention, the sources of the main raw materials used are as follows. Other raw materials and reagents, unless otherwise specified, were purchased from commercial sources:

[0056] Component (A) Toluene diisocyanate:

[0057] Isocyanate 1: WANNATE TDI-65, 65wt.% 2,4-toluene diisocyanate, 35wt.% 2,6-toluene diisocyanate, NCO content 48.3%, Wanhua Chemical Group Co., Ltd.;

[0058] Isocyanate 2: WANNATE TDI-80, 80wt.% 2,4-toluene diisocyanate, 20wt.% 2,6-toluene diisocyanate, NCO content 48.3%, Wanhua Chemical Group Co., Ltd.;

[0059] Component (B) polyether polyol:

[0060] Polyether polyol 1: F3135, glycerol-based, hydroxyl value 35 mgKOH / g, Wanhua Chemical Group Co., Ltd.

[0061] Polyether polyol 2: F3128, glycerol-based, hydroxyl value 28 mgKOH / g, Wanhua Chemical Group Co., Ltd.

[0062] Component (C) Metal Compound Catalyst:

[0063] Catalyst 1: sodium bisulfite, ≥58.5% (SO2), Innochem;

[0064] Catalyst 2: sodium hydroxide, 96%, Aladdin;

[0065] Catalyst 3: sodium dodecylbenzene sulfonate, 95%, Aladdin;

[0066] Component (E) inhibitor:

[0067] Inhibitor 1: benzoyl chloride, 99%, Innochem;

[0068] Inhibitor 2: adipoyl chloride, 98%, Tci;

[0069] PM-200: WANNATE PM-200, polymethylene polyphenyl polyisocyanate, NCO content 31.2%, Wanhua Chemical Group Co., Ltd.

[0070] Di-n-butylamine: Aladdin.

[0071] Embodiment 1:

[0072] (1) Add 840 g of isocyanate 2 and 140 g of polyether polyol 2 into a 2000 ml three-necked round-bottom flask, place the reaction system in a 70° C. oil bath, and react at a constant temperature for 1 h.

[0073] (2) 18 g of water and 10 ppm of catalyst 1 were added to the above reaction system. After reacting at 70° C. for 10 min, the temperature was raised to 140° C. and the reaction was continued for 1.5 h.

[0074] (3) Add 20 ppm of inhibitor 2 to the reaction system and continue the reaction at 140°C for 10 min.

[0075] A light yellow transparent modified toluene diisocyanate composition (modified TDI-1) was obtained, and the NCO content was measured to be 30.94%, and the viscosity was measured to be 1072 mPa·s.

[0076] Embodiment 2-6:

[0077] According to the method provided in Example 1, the modified toluene diisocyanate compositions (modified TDI-2 to modified TDI-6) were prepared using the material ratios and reaction parameters in Table 1. The test results are shown in Table 2.

[0078] Table 1 Raw materials and reaction parameters for preparing modified TDI compositions of Examples 1-6

[0079]

[0080]

[0081] Comparative Example 1:

[0082] (1) Add 840 g of isocyanate 1 and 140 g of polyether polyol 1 into a 2000 ml three-necked round-bottom flask, place the reaction system in a 70° C. oil bath, and react at a constant temperature for 1 h.

[0083] (2) 20 ppm of inhibitor 2 was added to the reaction system, and the reaction was continued at 70° C. for 10 min to obtain a light yellow transparent modified toluene diisocyanate composition (modified TDI-7). The NCO content was measured to be 40.80% and the viscosity was measured to be 136 mPa·s.

[0084] Comparative Example 2:

[0085] (1) Add 840g of isocyanate 2, 84g of di-n-butylamine, and 0.126g of zinc acetylacetonate to a 2000ml three-necked round-bottom flask, place the reaction system in a 90°C oil bath, and react at this temperature for 2h. Then add 0.252g of benzoyl chloride, and cool the reaction mixture to 25°C to obtain a clear yellow biuret-modified TDI-80 (ISO A).

[0086] (2) Add 779 g of ISO A and 221 g of polyether polyol 1 into a 2000 ml three-necked round-bottom flask, place the reaction system in a 60° C. oil bath, react at constant temperature for 2 h, and then cool to 25° C.

[0087] A light yellow transparent modified toluene diisocyanate composition (modified TDI-8) was obtained, and the NCO content was measured to be 27.95%, and the viscosity was measured to be 155 mPa0s.

[0088] The isocyanate products of Examples 1-6 and Comparative Examples 1-3 were tested for their characteristic parameters according to the following method. The results are shown in Table 2:

[0089] NCO content GB / T 12009.4-2016;

[0090] Viscosity GB / T 12008.7-2010;

[0091] The contents of compounds containing carbamate groups, biuret groups, triuret groups and polyuret groups were tested and calculated by GPC, liquid chromatography-mass spectrometry, and nuclear magnetic resonance hydrogen and carbon spectra.

[0092] Table 2 Test results of characteristic parameters of isocyanate products prepared in Examples 1-6 and Comparative Examples 1-3

[0093]

[0094] Performance Test:

[0095] The modified TDI compositions prepared in Examples 1-6 and the isocyanate products of Comparative Examples 1-3 were mixed with TDI in proportion to prepare an isocyanate mixture, and the Wanhua combined polyether product was used to prepare free foams, which were then prepared into 40*40*10cm thick foams in an aluminum mold. 3 The performance of the foam samples was tested by the following methods:

[0096]

[0097]

[0098] The free foam refers to the foam obtained by free growth in an open container after the combined polyether and isocyanate are fully mixed; the core density refers to the core density of the foam prepared in an aluminum mold.

[0099] Test Example 1:

[0100] The modified TDI compositions prepared in Examples 1-6 and the isocyanate products of Comparative Examples 1-3 were mixed with TDI in a ratio of 20%:80% (mass ratio) to prepare an isocyanate mixture, and the foam was prepared and tested with Wanhua combined polyether product WANEFLEX 311BR. The results are shown in Table 3.

[0101] Table 3 Test results of modified TDI composition in TM20 system foam

[0102]

[0103] Test Example 2:

[0104] The modified TDI compositions prepared in Examples 1-6 and the isocyanate products of Comparative Examples 1-3 were mixed with TDI at a ratio of 40%:60% (mass ratio) to prepare an isocyanate mixture, and the foam was prepared and tested with Wanhua combined polyether product WANEFLEX 325M. The results are shown in Table 4.

[0105] Table 4 Test results of modified TDI composition in TM40 system foam

[0106]

[0107] From the above results, it can be seen that in Comparative Examples 1 and 2, when modified TDI-7 and modified TDI-8 were used to prepare isocyanate mixtures with TDI in proportion, and Wanhua combined polyether products were used, free bubbles collapsed during the preparation of foam, and the free bubble density could not be tested. When preparing foam in an aluminum mold, cavities caused by collapsed bubbles appeared inside, and performance testing could not be performed.

[0108] By comparing the test results of the embodiments and the comparative examples, it is found that the isocyanate product prepared by mixing the modified TDI composition containing structures such as biuret, triuret, and polyuret according to the present invention with TDI in a specific ratio has a wider viscosity range than the isocyanate product prepared by mixing the traditional PMDI with TDI in a specific ratio (different viscosity products can be customized for customers to match the existing equipment of customers, thereby improving the quality of foam products. At the same time, the free foam density prepared by the modified TDI composition is lower, and a foam product with a lower density can be produced, thereby reducing the cost of raw materials. The performance of the foam product prepared by the modified TDI composition is basically similar to that of the foam product prepared by PMDI, and it has better advantages in terms of elongation at break, tear strength, horizontal combustion, etc.

[0109] In summary, the present invention has developed a modified TDI composition that can replace PMDI, and can prepare foam products with lower density, meeting the needs of existing automobile OEMs to reduce costs and increase efficiency. At the same time, the viscosity is controllable, and the mixing effect with the combined polyether polyol is better, which improves the appearance quality and yield rate of foam products.

Claims

1. A modified toluene diisocyanate composition, characterized in that: The invention comprises 9-20 wt % of a compound containing a carbamate group, 20-25 wt % of a compound containing a biuret group, and 25-30 wt % of a compound containing a triuret group and a polyuret group.

2. The modified toluene diisocyanate composition according to claim 1, characterized in that: The modified toluene diisocyanate composition, wherein the isocyanate group (NCO) content is 29.0-33.0%; and / or The modified toluene diisocyanate composition has a viscosity of 500-15000 mPa·s at 25°C.

3. The modified toluene diisocyanate composition according to claim 1 or 2, characterized in that: Obtained by reacting the following raw materials: (A) toluene diisocyanate; (B) polyether polyol; (C) a metal compound catalyst; (D) Water; (E) Inhibitor.

4. The modified toluene diisocyanate composition according to claim 3, characterized in that: The amount of the polyether polyol added is 10-20% of the mass of toluene diisocyanate; and / or The amount of water added is 1.9-2.4% of the mass of toluene diisocyanate; and / or The amount of the metal compound catalyst added is 10-20 ppm based on the mass of toluene diisocyanate; and / or The addition amount of the polymerization inhibitor is 20-50 ppm based on the mass of toluene diisocyanate.

5. The modified toluene diisocyanate composition according to claim 3, characterized in that: Component (A) the toluene diisocyanate, wherein the isocyanate group (NCO) content is 48.0-48.5wt%; and / or The toluene diisocyanate of component (A) is one or a mixture of 2,6-toluene diisocyanate and 2,4-toluene diisocyanate; Preferably, the toluene diisocyanate comprises 0-40wt% of 2,6-toluene diisocyanate and 60-100wt% of 2,4-toluene diisocyanate, wherein the sum of the mass percentages of 2,6-toluene diisocyanate and 2,4-toluene diisocyanate is 100wt%; More preferably, the toluene diisocyanate comprises 20-40 wt % of 2,6-toluene diisocyanate and 60-80 wt % of 2,4-toluene diisocyanate, wherein the sum of the mass percentages of 2,6-toluene diisocyanate and 2,4-toluene diisocyanate is 100 wt %.

6. The modified toluene diisocyanate composition according to claim 3, characterized in that: The polyether polyol of component (B) is selected from one or more of petroleum-based polyether polyols and bio-based polyether polyols; Preferably, the polyether polyol is selected from one or more polyether polyols having an average functionality of 3 and a hydroxyl value of 25-40 mgKOH / g; and / or The metal compound catalyst of component (C) is selected from an inorganic metal catalyst and an organic metal catalyst, preferably one or more of potassium hydroxide, sodium hydroxide, sodium sulfate, potassium sulfate, potassium sulfite, sodium sulfite, sodium bisulfite, sodium carbonate, sodium bicarbonate, sodium dodecylbenzene sulfonate, and sodium dodecyl sulfate, more preferably one or more of potassium hydroxide, sodium hydroxide, sodium carbonate, sodium bisulfite, sodium dodecylbenzene sulfonate, and sodium dodecyl sulfate, further preferably one or more of potassium hydroxide, sodium hydroxide, and sodium dodecylbenzene sulfonate; and / or The polymerization inhibitor of component (E) is selected from one or more of acyl chlorides, phenols and dimethyl ester compounds, preferably one or more of benzoyl chloride, adipoyl chloride, phosphoric acid, dimethyl sulfate, resorcinol and hydroquinone.

7. A method for preparing the modified toluene diisocyanate composition according to any one of claims 1 to 6, characterized in that: The steps include: S1: a prepolymer is formed by the reaction of toluene diisocyanate and polyether polyol; S2: adding a metal compound catalyst and water to the prepolymer to carry out a first-stage reaction, and then raising the temperature to carry out a second-stage reaction; S3: adding a polymerization inhibitor and continuing the reaction until the desired viscosity is reached to obtain a modified toluene diisocyanate composition.

8. The preparation method according to claim 7, characterized in that: The reaction in step S1 is carried out at a temperature of 60-80°C for a time of 0.5-1h; and / or Step S2: the first stage reaction, the temperature is 60-80°C, the time is 10-15min; the second stage reaction, the temperature is 110-140°C, the time is 1-6h; and / or The reaction in step S3 is carried out at a temperature of 110-140° C. and for a time of 10-30 min.

9. Use of the modified toluene diisocyanate composition according to any one of claims 1 to 6 as a PMDI substitute.

10. Use of the modified toluene diisocyanate composition according to any one of claims 1 to 6 in high resilience polyurethane foam.

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