A modified toluene diisocyanate composition, and a method of making and using the same

Abstract

The application discloses a modified toluene diisocyanate composition, a preparation method and application thereof, and belongs to the field of polyurethane foaming materials. The modified toluene diisocyanate composition comprises 9-20 wt% of a compound containing a urethane 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 diisocyanate composition is 29.0-33.0%, and the viscosity at 25 DEG C is 500-15000 mPa s. The modified toluene diisocyanate composition can replace PMDI and is applied to the field of high-rebound polyurethane foaming.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of polyurethane, and relates to a modified toluene diisocyanate (modified TDI) composition capable of replacing PMDI (poly-methylene poly-phenyl poly-isocyanate) and a preparation method thereof. In particular, the present application relates to a modified toluene diisocyanate composition containing urethane groups and biuret groups, triuret groups, polyuret groups and the like, and a preparation method thereof, which can be used for the preparation of high resilience polyurethane foam. BACKGROUND

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

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

[0004] The foam prepared by mixing TDI and PMDI in a certain proportion can have the advantages of both. The PMDI content in the commonly used TM system on the market accounts for 20-60%, the TDI content accounts for 80%-40%, the NCO is 38.0-45.0%, and the viscosity is 10-40 mPa·s (25°C). The viscosity of the combined polyether polyol is 1000-3500 mPa·s (25°C). When the two raw materials with large difference in viscosity are mixed and foamed in a specific weight ratio, the precision of the polyurethane high-pressure foaming equipment is required to be high, and the problems of poor mixing, soft and hard foam products often occur, especially when the TDI content is higher and the viscosity is lower. The TM product is more obvious. In addition, in recent years, the price of TDI is generally lower than that of PMDI, and the modified TDI has an advantage in cost by replacing PMDI.

[0005] CN 108026247 B discloses a TDI biuret with a 40% NCO content, which is reacted with PMDI or other isocyanates, polyols to form a total NCO content of less than 7% polyurethane prepolymer, which can have a viscosity of less than about 10000 mPa s at 50℃, used for reducing fog-like polyurethane foam in the field of sealing, insulation. The prepolymer disclosed in the patent does not use water in the reaction, the NCO content is small, the viscosity is uncontrollable, and the plasticizer and the like can play a defoaming role to form a collapsed bubble, which is not suitable for high resilience polyurethane foaming system.

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

[0007] In order to solve the problems in the prior art, the present application provides a modified toluene diisocyanate (modified TDI) composition, which contains urethane groups and biuret groups, tris-biuret groups, poly-biuret groups and the like, can replace PMDI and be used in high resilience polyurethane foam system. Compared with PMDI, the modified TDI composition provided by the present application has a higher foaming ratio, the density of the produced product is reduced by 5-10%, the viscosity is increased and controllable in the range of 500-15000 mPa s, thereby significantly improving the mixing property with the combined polyether polyol, and greatly reducing the cost.

[0008] Meanwhile, the present application provides a preparation method of the modified TDI composition, which provides flexible segments by modifying urethane groups, and gives the product excellent compression deformation, resilience and comfort, and provides rigid segments by modifying biuret, tris-biuret and poly-biuret groups, and gives the product low density, high hardness, high viscosity and high flame retardant properties.

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

[0010] In order to achieve the above purposes, the technical scheme of the present application is as follows:

[0011] In a first aspect, the present application provides a modified toluene diisocyanate composition, which contains 9-20 wt% of a compound containing urethane groups, 20-25 wt% of a compound containing biuret groups, and 25-30 wt% of a compound containing tris-biuret groups and poly-biuret groups.

[0012] The modified toluene diisocyanate composition of the present application further comprises unmodified toluene diisocyanate, and the sum of the mass percentage of the unmodified toluene diisocyanate and the compound containing urethane groups, the compound containing biuret groups, and the compound containing tri- and poly-uretide groups is 100%.

[0013] Specifically, the content of the compound containing urethane groups includes but is not limited to 9 wt%, 10 wt%, 11 wt%, 12 wt%, 13 wt%, 14 wt%, 15 wt%, 16 wt%, 17 wt%, 18 wt%, 19 wt%, 20 wt%, or a range consisting of any two of them; the content of the compound containing biuret groups includes but is not limited to 20 wt%, 20.5 wt%, 21 wt%, 21.5 wt%, 22 wt%, 22.5 wt%, 23 wt%, 23.5 wt%, 24 wt%, 24.5 wt%, 25 wt%, or a range consisting of any two of them; the content of the compound containing tri- and poly-uretide groups includes but is not limited to 25 wt%, 25.5 wt%, 26 wt%, 26.5 wt%, 27 wt%, 27.5 wt%, 28 wt%, 28.5 wt%, 29 wt%, 29.5 wt%, 30 wt%, or a range consisting of any two of them.

[0014] The modified toluene diisocyanate composition of the present application contains urethane groups, biuret groups, tri-uretide groups, and poly-uretide groups, wherein the flexible segments are provided by the urethane group modified segments, and the rigid segments are provided by the biuret, tri-uretide, poly-uretide, etc. groups modified segments, and the combination of the two can produce foams with high resilience, good comfort, 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 a range consisting of any two of them. When the NCO content is lower than 29.0%, the polyurethane foam produced therefrom has high density. When the NCO content is higher than 33.0%, the foaming process is prone to collapse due to the low content of biuret, tri-uretide, poly-uretide, etc. groups, and the tolerance is poor.

[0016] In an 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 of them. When the viscosity of the modified TDI is less than 500 mPa-s, the difference in viscosity with the combined polyether is large, and the problem of poor mixing is prone to occur, affecting the production qualified rate of the foam. When the viscosity is greater than 15000 mPa-s, the flowability is poor, which is not conducive to the molding of the foam in subsequent applications.

[0017] The modified toluene diisocyanate composition described above can be prepared using known raw materials according to conventional reaction processes in the art, for example, by reacting toluene diisocyanate with polyether polyol, water in the presence of a catalyst;

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

[0019] (A) toluene diisocyanate;

[0020] (B) polyether polyol;

[0021] (C) metal compound catalyst;

[0022] (D) water;

[0023] (E) polymerization inhibitor.

[0024] In some specific examples, the polyether polyol is added in an amount of 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 between any two of them; and / or

[0025] The water is added in an amount of 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 a range between any two of them; and / or

[0026] The metal compound catalyst is added in an amount of 10-20 ppm by mass of the 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 formed by any two of them; and / or

[0027] The polymerization inhibitor is added in an amount of 20-50 ppm by mass of the toluene diisocyanate, including but not limited to 20 ppm, 22 ppm, 25 ppm, 28 ppm, 30 ppm, 32 ppm, 35 ppm, 38 ppm, 40 ppm, 42 ppm, 45 ppm, 48 ppm, 50 ppm, or a range formed by any two of them.

[0028] In some specific examples, the toluene diisocyanate of component (A) has an isocyanate group (NCO) content of 48.0-48.5 wt%, including but not limited to 48 wt%, 48.1 wt%, 48.2 wt%, 48.3 wt%, 48.4 wt%, 48.5 wt%, or a range formed by any two of them; 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 0-40 wt% of 2,6-toluene diisocyanate and 60-100 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%; in particular, the content of 2,6-toluene diisocyanate includes but is not limited to 0 wt%, 5 wt%, 15 wt%, 20 wt%, 25 wt%, 30 wt%, 35 wt%, 40 wt%, or a range formed by any two of them;

[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 polyols, bio-based polyether polyols;

[0033] Preferably, the polyether polyol is selected from one or more of 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 urethane groups, while catalyzing the reaction of isocyanate groups with water to form urea structures, and on this basis, continue to react with water, isocyanate groups to form substances containing biuret, triuret and polyuret structures under certain conditions;

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

[0038] In a second aspect, the present application provides a preparation method of the above-mentioned modified toluene diisocyanate composition, which can be carried out by using conventional reaction processes in the art, for example, by reacting toluene diisocyanate with polyether polyols and water in the presence of a catalyst.

[0039] A preparation method of a modified toluene diisocyanate composition, comprising the following steps:

[0040] S1: reacting toluene diisocyanate with polyether polyols to form a prepolymer;

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

[0042] S3: adding a polymerization inhibitor to continue the reaction to the desired viscosity to obtain a modified toluene diisocyanate.

[0043] For the preparation method of the present application, the raw material selection and dosage range listed above can be referred to. For other related operations and process conditions, and the devices used, the corresponding conventional selection in the art can be used, and there is no special limitation. The skilled person can optimize it according to the actual needs based on the known process in the prior art, and the specific conditions listed in the following embodiments of the present application can be used:

[0044] In some specific examples, the reaction in step S1 is carried out at a temperature of 60-80°C for 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 consisting of any two of them; the time includes but is not limited to 0.5h, 0.6h, 0.7h, 0.8h, 0.9h, 1h, or a range consisting of any two of them.

[0045] In some specific examples, the first stage reaction in step S2 is carried out at a temperature of 60-80°C for a time of 10-15min; 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 consisting of any two of them; the time includes but is not limited to 10min, 11min, 12min, 13min, 14min, 15min, or a range consisting of any two of them; and / or

[0046] The second stage reaction is carried out at a temperature of 110-140°C for 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 consisting of any two of them; the time includes but is not limited to 1h, 2h, 3h, 4h, 5h, 6h, or a range consisting of any two of them.

[0047] In some specific examples, the reaction in step S3 is carried out at a temperature of 110-140°C for a time of 10-30min; 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 consisting of any two of them; the time includes but is not limited to 10min, 12min, 15min, 18min, 20minn, 22min, 25min, 28min, 30min, or a range consisting of any two of them.

[0048] In the example preparation method of the present application, after the reaction of toluene diisocyanate with polyether polyol is completed, water is added to the prepolymer, and the isocyanate groups react with water under the action of a catalyst to form a urea structure. During this reaction process, a large amount of gas is generated, and the system changes from a colorless transparent liquid to a white or light white liquid. Subsequently, the temperature is raised, and the reaction with water continues at high temperature to form modified toluene diisocyanate containing biuret, triuret and polyuret structures, and the system changes from a white or light white liquid to a yellow or light yellow transparent liquid. During this process, the temperature is controlled within a certain range to promote the continued reaction of NCO with urea, shorten the reaction time, and increase the viscosity of the system. Finally, a suitable amount of polymerization inhibitor is added to terminate the reaction, and the modified toluene diisocyanate composition with the desired viscosity is obtained.

[0049] In a third aspect, the present application also provides the use of the modified toluene diisocyanate composition described above.

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

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

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

[0053] The present application provides a modified TDI composition with a viscosity of 500-15000 mPa·s (25℃) and an NCO content of 29.0-33.0%, which replaces PMDI in the TM system on the market, can be prepared into an isocyanate product, and is used in the production of high resilience polyurethane foam. Compared with the TM system product 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 the property of close viscosity to the combined polyether polyol, has good mixing property with the combined polyether polyol, the produced foam has good mechanical properties, and has the advantage of low cost, and can be used in the manufacture of automobile seats and other parts. DETAILED DESCRIPTION

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

[0055] In the examples and comparative examples of the present application, the sources of the main raw materials used are as follows, and other raw materials and reagents are purchased through commercial channels unless otherwise specified:

[0056] Component (A) toluene diisocyanate:

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

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

[0059] Component (B) polyether polyol:

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

[0061] Polyether polyol 2: F3128, glycerol starting, 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 dodecyl benzene sulfonate, 95%, Aladdin;

[0066] Component (E) polymerization inhibitor:

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

[0068] Polymerization 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] Example 1:

[0072] (1) In a 2000 ml three-necked round bottom flask, 840 g of isocyanate 2 and 140 g of polyether polyol 2 were added, and the reaction system was placed in a 70°C oil bath, and reacted for 1 h.

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

[0074] (3) 20 ppm of polymerization inhibitor 2 was added to the reaction system, and reacted at 140°C for 10 min,

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

[0076] Examples 2-6:

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

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

[0079]

[0080]

[0081] Comparative Example 1:

[0082] (1) In a 2000 ml three-necked round bottom flask, 840 g of isocyanate 1 and 140 g of polyether polyol 1 were added, and the reaction system was placed in a 70°C oil bath, and reacted for 1 h.

[0083] (2) 20 ppm of polymerization inhibitor 2 was added to the reaction system, and reacted 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) In a 2000ml three-necked round bottom flask, 840g of isocyanate 2, 84g of di-n-butylamine, 0.126g of zinc acetylacetonate were added, and the reaction system was placed in a 90°C oil bath for constant temperature reaction for 2h. Then 0.252g of benzoyl chloride was added, and the reaction mixture was cooled to 25°C to obtain a clear yellow biuret modified TDI-80 (ISO A).

[0086] (2) In a 2000ml three-necked round bottom flask, 779g of ISO A, 221g of polyether polyol 1 were added, and the reaction system was placed in a 60°C oil bath for constant temperature reaction for 2h, and then cooled to 25°C.

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

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

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

[0090] Viscosity GB / T 12008.7-2010;

[0091] The content of compounds containing urethane groups, biuret groups, triurea groups and polyurea groups was tested and calculated by GPC, liquid chromatography-mass spectrometry, and nuclear magnetic 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 a certain proportion to prepare an isocyanate mixture, which was mixed with Wanhua combined polyether product to prepare a free foam, and a 40*40*10cm 3 size foam sample was prepared in an aluminum mold, and its performance was tested according to the following methods:

[0096]

[0097]

[0098] Free foam refers to the foam obtained by allowing the combined polyether and isocyanate to mix freely in an open container; 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 at a ratio of 20%:80% (mass ratio) to prepare an isocyanate mixture, which was then mixed with the Wanhua combined polyether product WANEFLEX 311BR to prepare a foam and test the foam, with the results shown in Table 3.

[0101] Table 3 Test results of modified TDI compositions in TM20 system foams

[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, which was then mixed with the Wanhua combined polyether product WANEFLEX 325M to prepare a foam and test the foam, with the results shown in Table 4.

[0105] Table 4 Test results of modified TDI compositions in TM40 system foams

[0106]

[0107] As can be seen from the above results, in Comparative Example 1 and Comparative Example 2, the modified TDI-7 and modified TDI-8 were mixed with TDI at a ratio to prepare an isocyanate mixture, which was then mixed with the Wanhua combined polyether product to prepare a foam, and the free foam collapsed, and the free foam density could not be tested. The foam prepared in the aluminum mold had cavities caused by internal collapse, and the performance test could not be performed.

[0108] By comparing the test results of the examples and the comparative examples, it is found that the isocyanate product prepared by mixing the modified TDI composition containing a biuret, triuret, polyuret, etc. structure and TDI at a specific ratio according to the present application has a wider viscosity range compared with the isocyanate product prepared by mixing the traditional PMDI and TDI at a specific ratio, which can customize different viscosity products for customers to match the existing equipment of the customers and improve the quality of the foam product. At the same time, the free foam density prepared by the modified TDI composition is lower, which can produce a lower density foam product and reduce the raw material cost. 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 has better advantages in terms of elongation at break, tear strength, horizontal burning, etc.

[0109] In summary, the present application develops a modified TDI composition that can replace PMDI, which can produce lower density foam products, matching the needs of existing automobile manufacturers 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, improving the appearance quality and yield of the foam products.

Claims

1. A modified toluene diisocyanate composition, characterized in that, It contains 9-20 wt% of compounds containing urethane groups, 20-25 wt% of compounds containing biuret groups, and 25-30 wt% of compounds containing triuret and polyuret groups; The modified toluene diisocyanate composition contains an isocyanate group (NCO) content of 29.0-33.0%. The modified toluene diisocyanate composition has a viscosity of 500-15000 mPa·s at 25°C.

2. The modified toluene diisocyanate composition according to claim 1, characterized in that, Obtained by reacting a starting material comprising the following components: (A) Toluene diisocyanate; (B) Polyether polyols; (C) Metal compound catalysts; (D) Water; (E) Polymerization inhibitor.

3. The modified toluene diisocyanate composition according to claim 2, 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 of the mass of toluene diisocyanate; and / or The amount of the polymerization inhibitor added is 20-50 ppm of the mass of toluene diisocyanate.

4. The modified toluene diisocyanate composition according to claim 2, characterized in that, Component (A) is the toluene diisocyanate, wherein the isocyanate group (NCO) content is 48.0-48.5 wt%; and / or The toluene diisocyanate in component (A) is one or a mixture of two of 2,6-toluene diisocyanate and 2,4-toluene diisocyanate.

5. The modified toluene diisocyanate composition according to claim 4, characterized in that, The toluene diisocyanate comprises 0-40 wt% of 2,6-toluene diisocyanate and 60-100 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 5, characterized in that, 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%.

7. The modified toluene diisocyanate composition according to claim 2, characterized in that, The polyether polyol in component (B) is selected from one or more of petroleum-based polyether polyols and bio-based polyether polyols; and / or The metal compound catalyst described in component (C) is selected from inorganic metal catalysts and organometallic catalysts; and / or The polymerization inhibitor in component (E) is selected from one or more of acyl chlorides, phenols, and dimethyl esters.

8. The modified toluene diisocyanate composition according to claim 7, characterized in that, The polyether polyol in component (B) is selected from one or more polyether polyols with an average functionality of 3 and a hydroxyl value of 25-40 mg KOH / g.

9. The modified toluene diisocyanate composition according to claim 7, characterized in that, The metal compound catalyst in component (C) is selected from one or more of potassium hydroxide, sodium hydroxide, sodium sulfate, potassium sulfate, potassium sulfite, sodium sulfite, sodium bisulfite, sodium carbonate, sodium bicarbonate, sodium dodecylbenzenesulfonate, and sodium dodecyl sulfate.

10. The modified toluene diisocyanate composition according to claim 9, characterized in that, The metal compound catalyst is selected from one or more of potassium hydroxide, sodium hydroxide, sodium carbonate, sodium bisulfite, sodium dodecylbenzenesulfonate, and sodium dodecyl sulfate.

11. The modified toluene diisocyanate composition according to claim 2, characterized in that, The polymerization inhibitor in component (E) is selected from one or more of benzoyl chloride, adipic acid chloride, phosphoric acid, dimethyl sulfate, resorcinol, and hydroquinone.

12. A method for preparing the modified toluene diisocyanate composition according to any one of claims 1-11, characterized in that, Includes the following steps: S1: A prepolymer is generated by reacting toluene diisocyanate with polyether polyol; S2: Add a metal compound catalyst and water to the prepolymer to carry out the first stage reaction, and then raise the temperature to carry out the second stage reaction; S3: Add a polymerization inhibitor and continue the reaction until the desired viscosity is reached to obtain a modified toluene diisocyanate composition.

13. The preparation method according to claim 12, characterized in that, The reaction described in step S1 is carried out at a temperature of 60-80℃ for a time of 0.5-1 h; and / or Step S2: The first stage reaction is carried out at a temperature of 60-80℃ for 10-15 min; the second stage reaction is carried out at a temperature of 110-140℃ for 1-6 h; and / or The reaction described in step S3 is carried out at a temperature of 110-140℃ for 10-30 minutes.

14. The use of the modified toluene diisocyanate composition according to any one of claims 1-11 as a PMDI substitute.

15. The use of the modified toluene diisocyanate composition according to any one of claims 1-11 in high-resilience polyurethane foam.

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