Modified isocyanate and its preparation method and application

Abstract

The present invention relates to a modified isocyanate and a preparation method and application thereof, which mainly solves the problems of unstable storage and poor fluidity of the modified isocyanate in the prior art, low tensile strength and poor tearing performance of the prepared polyurethane foam. The present invention adopts a modified isocyanate, which comprises 11.3 to 92.1 parts by weight of an organic isocyanate, 0.3 to 17.2 parts by weight of a small molecule organic alcohol, 3.3 to 67.7 parts by weight of a polyether polyol, 50 to 500 ppm of an antioxidant, and 10 to 130 ppm of an inhibitor; the organic isocyanate is ...3.3 to 67.7 parts by weight of a polyether polyol, 3.3 to 67.7 parts by weight of a polyether polyol, 3.3 to 67.7 parts by weight of a polyether polyol, 3.3 to 67.7 parts by weight of a poly The polyol comprises 10 to 60 parts of 2,4-MDI, 20 to 70 parts of 4,4'-MDI, 10 to 50 parts of carbodiimide modified isocyanate, and 5 to 35 parts of polymethylene polyphenyl isocyanate; the polyether polyol has an average molecular weight of 450 to 2450, a functionality of 1 to 2.5, an EO content of 30 to 55%, a PO content of 60 to 75%, a primary hydroxyl content of 30 to 60%, and a preparation method thereof. The technical solution solves the above problems well and can be used in the industrial production of polyurethane high resilience or self-skinning products.

Description

Technical Field

[0001] The invention belongs to the field of polyurethane, and particularly relates to a modified isocyanate and a preparation method and application thereof. Background Art

[0002] As the main raw material in the polyurethane field, organic isocyanate is widely used in polyurethane foam, elastomer, adhesive and other industries; however, traditional monomers, monomer mixtures and polymers such as toluene diisocyanate and diphenylmethane diisocyanate have limitations in application tolerance, product performance, storage conditions, etc.; at the same time, it also has an important impact on the physical and mechanical properties of the product such as stretching and tearing.

[0003] Regarding the tensile tearing properties of products, the existing technical solutions mainly include the following three types: (1) Select different chain extenders and cross-linking agents to change the microstructure configuration and improve product performance; (2) Select polyethers, polyesters and other special polyols with specific structures to change the soft segment structure and improve product performance; (3) Organic isocyanate modification, mainly using carbamate modification and carbodiimide modification, to change the hard segment structure and improve product performance. In practical applications, factors such as wide formulation tolerance, simple and reliable operation, and low cost must also be considered. The above methods are difficult to meet the requirements at the same time, and the degree of improvement in the tensile tearing properties of products is limited. Therefore, it is particularly important to develop a modified isocyanate product that can greatly improve the tensile tearing properties of products and meet the requirements of practical applications.

[0004] Chinese patent CN101353413B discloses a modified MDI for cold-cured high-resilience foam plastics, comprising isocyanate, polyether polyol, modifier and polymerization inhibitor, wherein the total weight of isocyanate, polyether polyol and modifier is 100%, the isocyanate is 75-84%, the polyether polyol is 15-24%, the modifier is 0.5-1.9%, and the polymerization inhibitor is 10ppm based on the total weight of the raw materials, wherein the isocyanate is diphenylmethane diisocyanate and polymethylene polyphenyl isocyanate. A mixture of acid esters, the mass ratio of the two is 0.8-1.2, the polyether polyol has a functionality of 3 and a number average molecular weight of 5000-7000, the mass content of primary hydroxyl is 65-80%, glycerol is used as an initiator, polyoxypropylene triol is terminated with ethylene oxide, and the modifier is a siloxane-modified polyether polyol with a number average molecular weight of 2000-3000; a high-resilience foam with good hand feel, low density and good open cell performance is prepared, but the mechanical properties of the foam are general and the fluidity of the foaming material is poor.

[0005] Chinese patent CN101597370B discloses a water-foamed self-skinning polyurethane composition, its preparation method and application, wherein component B is a modified isocyanate with an NCO content of 18-29%, and comprises, by weight, 20-50 parts of prepolymer 1# (a prepolymer with an NCO content of 9-18% obtained by polymerizing 4,4'-MDI and polycaprolactone diol); 10-30 parts of prepolymer 2# (a prepolymer with an NCO content of 20-29% obtained by polymerizing 4,4'-MDI and a high-functionality polyether polyol); 5 ~10 parts of prepolymer 3# (a prepolymer with an NCO content of 26-30% obtained by polymerizing a mixture of 2,4-MDI and 4,4-MDI with a diol); 5-30 parts of a mixture of 2,4-MDI and 4,4'-MDI; 20-40 parts of 4,4'-MDI; 20-60 parts of carbodiimide-modified MDI; 3-30 parts of polymerized MDI; an environmentally friendly self-skinning polyurethane composition is prepared, but crude MDI is easily retained in the modified isocyanate component, the compatibility is poor, and turbidity and stratification are easy to occur during storage. Summary of the invention

[0006] One of the technical problems to be solved by the present invention is that the modified isocyanate in the prior art is unstable in storage, has poor fluidity, and the prepared polyurethane foam has low tensile strength and poor tearing performance. A modified isocyanate is provided, which has the advantages of stable storage, good fluidity, and the prepared polyurethane foam has high tensile strength and good tearing performance.

[0007] The second technical problem to be solved by the present invention is to provide a method for preparing a modified isocyanate corresponding to the first technical problem to be solved.

[0008] The third technical problem to be solved by the present invention is to provide an application of modified isocyanate corresponding to solving the first technical problem.

[0009] To solve one of the above technical problems, the technical solution provided by the present invention is as follows: a modified isocyanate, comprising, by weight: 11.3 to 92.1 parts of an organic isocyanate, 0.3 to 17.2 parts of a small molecule organic alcohol, 3.3 to 67.7 parts of a polyether polyol, 50 to 500 ppm of an antioxidant based on the total weight of the raw materials, and 10 to 130 ppm of an inhibitor based on the total weight of the raw materials; wherein the organic isocyanate comprises, by weight: 10 to 60 parts of 2,4-diphenylmethane diisocyanate, 20 to 70 parts of 4,4'-diphenylmethane diisocyanate, 10 to 5 0 parts of carbodiimide modified isocyanate, and 5 to 35 parts of polymethylene polyphenyl isocyanate; the small molecule organic alcohol is selected from at least one of monoalcohol or diol; the average molecular weight of the polyether polyol is 450 to 2450, the functionality is 1 to 2.5, the EO mass percentage is 30 to 55%, the PO mass percentage is 60 to 75%, and the primary hydroxyl mass percentage is 30 to 60%; the antioxidant is selected from at least one of hindered phenol antioxidants, hindered amine antioxidants or phosphite antioxidants; the inhibitor is selected from at least one of acyl chlorides or acids.

[0010] In the above technical solution, preferably, the mass percentage of isocyanate in the modified isocyanate is 16-32%.

[0011] In the above technical scheme, preferably, the relative molecular mass of the small molecule organic alcohol is 32 to 400; the monoalcohol is selected from at least one of ethanol, propanol, isopropanol, n-butanol, isobutanol, sec-butanol or n-pentanol; the diol is selected from at least one of 1,2-butanediol, 1,4-butanediol, methyl propanediol, 1,2-propylene glycol, 1,3-propylene glycol, 1,3-butanediol, diethylene glycol, dipropylene glycol, diethylene glycol monobutyl ether, dipropylene glycol monomethyl ether or dipropylene glycol monobutyl ether; the acyl chloride is selected from at least one of benzoyl chloride, phenylacetyl chloride or adipoyl chloride; the acid is selected from at least one of phosphoric acid, polyphosphoric acid, adipic acid, citric acid, tartaric acid or p-toluenesulfonic acid.

[0012] In the above technical solution, preferably, the functionality of the polyether polyol is 1.2-2.0, the mass percentage of EO is 34-45%, the mass percentage of PO is 66-73%, and the mass percentage of primary hydroxyl is 40-45%.

[0013] In the above technical solution, preferably, the organic isocyanate comprises, by mass, 12 to 23 parts of 2,4-diphenylmethane diisocyanate, 20 to 40 parts of 4,4'-diphenylmethane diisocyanate, 20 to 40 parts of carbodiimide-modified isocyanate and 7 to 19 parts of polymethylene polyphenyl isocyanate.

[0014] In the above technical scheme, preferably, the modified isocyanate comprises, by mass, 85 to 91.5 parts of organic isocyanate, 1.5 to 3 parts of small molecule organic alcohol, 5 to 27 parts of polyether polyol, 100 to 400 ppm of antioxidant based on the total mass of raw materials, and 10 to 130 ppm of inhibitor based on the total mass of raw materials.

[0015] To solve the second technical problem above, the present invention provides a technical solution as follows: a method for preparing a modified isocyanate, comprising the following steps:

[0016] (1) Prepare the raw materials according to the following component mass percentages:

[0017] The composition comprises, by weight: 11.3 to 92.1 parts of organic isocyanate, 0.3 to 17.2 parts of small molecule organic alcohol, 3.3 to 67.7 parts of polyether polyol, 50 to 500 ppm of antioxidant based on the total weight of raw materials, and 10 to 130 ppm of polymerization inhibitor based on the total weight of raw materials; wherein the organic isocyanate comprises, by weight: 10 to 60 parts of 2,4-diphenylmethane diisocyanate, 20 to 70 parts of 4,4'-diphenylmethane diisocyanate, 10 to 50 parts of carbodiimide modified isocyanate, and 5 to 35 parts of polymethylene polyphenyl isocyanate; the small molecule organic alcohol is selected from at least one of monools or diols; the average molecular weight of the polyether polyol is 450 to 2450, the functionality is 1 to 2.5, the EO mass percentage is 30 to 55%, the PO mass percentage is 60 to 75%, and the primary hydroxyl mass percentage is 30 to 60%; the antioxidant is selected from at least one of hindered phenol antioxidants, hindered amine antioxidants or phosphite antioxidants; the inhibitor is selected from at least one of acyl chlorides or acids;

[0018] (2) under the protection of a gas inert to the raw materials, mixing an isocyanate monomer, an antioxidant, a small molecule organic alcohol, and a polyether polyol to obtain material I;

[0019] (3) subjecting material I to a carbamate modification reaction at 55-90° C. to obtain material II;

[0020] (4) Sampling material II, and performing a quantitative test of the isocyanate group using an infrared spectrometer. When the mass percentage of the isocyanate group is measured to be 16 to 32%, adding an inhibitor to inhibit the reaction of isocyanate with carbamate and urea, as well as the self-polymerization reaction of isocyanate, to obtain material III;

[0021] (5) Lower the temperature of material III to 40-70° C. and stir for 2-4 hours to terminate the reaction to obtain modified isocyanate.

[0022] In the above technical scheme, preferably, the temperature of the carbamate modification reaction is 75-85°C; when the mass percentage of isocyanate in material II reaches 16-19%, an inhibitor is added; the temperature of material III is reduced to 55-65°C, stirred for 2-4 hours, and the reaction is terminated.

[0023] In order to solve the third of the above technical problems, the technical solution provided by the present invention is as follows: using modified isocyanate in the foaming application of polyurethane high-resilience or self-skinning products.

[0024] For polyether polyurethane, the imino group in the hard segment can form hydrogen bonds not only with its own carbonyl group, but also with the ether bond in the soft segment; for polyester polyurethane, the imino group can also form hydrogen bonds with the carbonyl group in the soft segment; the former represents microphase separation, and the latter represents microphase mixing. The amount of hydrogen bonding directly affects the degree of microphase separation of the system. Moreover, crosslinking and hard segment content have a significant effect on the degree of hydrogen bonding, and the formation of crosslinking can reduce the degree of hydrogen bonding; the increase in the hard segment content in polyether polyurethane increases the degree of hydrogen bonding of the carbonyl group, while the degree of hydrogen bonding between the imino group and the ether bond gradually decreases, and the degree of microphase separation increases accordingly. Therefore, hydrogen bonding, as a strong electrostatic force, affects the degree of phase separation, and thus affects the mechanical properties and aggregated structure of polyurethane.

[0025] The modified isocyanate of the present invention is prepared by screening the types and proportions of organic isocyanate, small molecule organic alcohol, polyether polyol, phosphite auxiliary antioxidant and hindered phenol main antioxidant, so that different components cooperate with each other, and the obtained modified isocyanate has a moderate reaction rate and good fluidity, which can shorten the production cycle of products and improve the qualified rate of products; at the same time, the crystallization temperature of the product is effectively reduced, so that the product has excellent high and low temperature storage performance, and no crystallization occurs when stored at -15°C for 3 months, no crystallization or barrel swelling occurs when stored at room temperature for 3 months, no crystallization occurs when stored at 60°C for 72 hours, and the product can be stored for more than 6 months under normal weather conditions. The modified isocyanate has a special segment structure and configuration, so that the modified isocyanate forms a reasonable group distribution configuration and distribution density, and the phase separation degree of the polyurethane foam product obtained after the polyurethane foaming is more sufficient, and the tensile strength, elongation at break, tear strength and other mechanical properties of the polyurethane foam product are improved, so that the tensile strength of the foam is as high as 785kPa, the elongation at break is 275%, and the tear strength is 13.6N / cm; therefore, the modified isocyanate of the present invention has the advantages of moderate reaction rate, good fluidity, stable storage, and the prepared polyurethane foam product has excellent tensile properties and tear properties, and a good technical effect is achieved.

[0026] The storage stability evaluation method of the modified isocyanate in the present invention is as follows:

[0027] The modified isocyanate sample was sealed in a 500 mL iron bottle and stored at room temperature for 3 months to observe its crystallization state and whether it was bulging.

[0028] The modified isocyanate sample was sealed in a 500 mL iron bottle and stored at -15°C for 3 months to observe its crystallization state;

[0029] The modified isocyanate sample was sealed in a 500 mL iron bottle, stored at 60°C for 72 hours, and observed for bulging.

[0030] The fluidity evaluation method of the modified isocyanate foaming material in the present invention is as follows:

[0031] Using the fluidity evaluation mold in Chinese utility model patent CN 202023181312.7, 100g of the molding foam formula was poured into the reaction tank at 45°C for 2 minutes. The mold was opened to take out the annular sample, and the length of the annular sample was measured to obtain the flow circumference to evaluate the fluidity.

[0032] The performance testing method of the molded foam product in the present invention is as follows:

[0033] Tensile strength (kPa): GB / T 6344-2008;

[0034] Elongation at break (%): GB / T 6344-2008;

[0035] Tear strength (N / cm): GB / T 10808-2006. DETAILED DESCRIPTION

[0036] The present invention will be further described below by way of examples, but is not limited thereto.

[0037] Table 1 List of raw materials

[0038]

[0039]

[0040] [Example 1]

[0041] A modified isocyanate, the preparation method of which comprises the following steps:

[0042] (1) Under the protection of nitrogen, add 750 g Lupranate MS, 750 g Lupranate MIPS, 360 g Lupranate M20S, and 1140 g Cosmonate LL into a 5 L glass reactor, heat to 75 ° C, and stir until completely melted;

[0043] (2) adding 0.34 g of 2,6-di-tert-butyl-4-methylphenol and 0.34 g of pentaerythritol diphosphite diisobutyl ester to the small molecule organic alcohol, mixing them evenly, adding them to the reaction kettle, and stirring them evenly;

[0044] (3) Heat the reactor to 80°C, add 238.2 g of polyether A, and stir to react for 2 hours;

[0045] (4) Add 0.17 g of phenylacetyl chloride into the reaction kettle, raise the temperature to 85° C., and react for 1 hour;

[0046] (5) The material in the reaction kettle was cooled to 60° C. and stirred for 2 hours to obtain a modified isocyanate; the performance of the modified isocyanate was evaluated, and the result data are shown in Table 4;

[0047] The prepared modified isocyanate was prepared according to the foaming formula in Table 3, and the fluidity evaluation mold in the Chinese utility model patent CN202023181312.7 was used. 100 g of the molded foam formula was poured into the reaction tank at 45 ° C. and aged for 2 minutes. The mold was opened to take out the annular sample, and the length of the annular sample was measured to obtain the flow circumference. The result data are shown in Table 4;

[0048] Pour the remaining molded foam formula into the foaming mold for foaming and sample preparation. The mold temperature is 50°C, the demoulding time is 2 minutes, and the overall density is 80kg / m 3 The obtained polyurethane foam was matured for 48 hours before performance testing. The result data are shown in Table 4.

[0049] [Examples 2 to 5]

[0050] The preparation methods of the modified isocyanates in Examples 2 to 5 are carried out according to the steps in Example 1, except that the reaction raw materials and the raw material ratios are different, as shown in Table 2. The storage stability data of the prepared modified isocyanates are shown in Table 4. The prepared modified isocyanates are formulated according to the foaming formula in Table 3, 100 g is taken for fluidity evaluation, and the remaining formula materials are foamed. The fluidity result data and the performance data of the polyurethane foam are shown in Table 4.

[0051] Table 2 The mass of each component raw material in Examples 1 to 5 (g)

[0052] Raw material name Example 1 Example 2 Example 3 Example 4 Example 5 Lupranate MS 750 750 750 1050 750 Lupranate MIPS 750 750 750 450 750 Lupranate M20S 360 360 360 360 360 Cosmonate LL 1140 1140 1140 1140 1140 Polyether A 238.2 / / 238.2 235.8 Polyether B / 220.2 / / / Polyether C / / 164.6 / / Ethylene glycol 59.1 / / / 59.1 Diethylene glycol 90 90 90 90 / Phenylacetyl chloride 0.17 0.17 0.17 0.17 0.17 2,6-Di-tert-butyl-4-methylphenol 0.34 0.34 0.34 0.34 0.34 Pentaerythritol diphosphite diisobutyl ester 0.34 0.34 0.34 0.34 0.34

[0053] Table 3 Mass fractions of each component in the molded foaming formula of Examples 1 to 5 and Comparative Examples 1 to 2

[0054] Raw material name Mass fraction CHE-1Q59 80 CHP-H45 20 Diethanolamine 1.2 CHK-9701 0.9 DABCO BL-11 0.2 DABCO MP 608 1.1 B-8734 1.0 water 2.3 index 85 Modified isocyanate 51.2

[0055] [Comparative Example 1]

[0056] In Comparative Example 1, the modified isocyanate used was commercially available Suprasec 2412, and its storage stability data is shown in Table 4; the modified isocyanate was formulated according to the foaming formula in Table 3, 100 g was taken for fluidity evaluation, and the remaining formula was foamed. The fluidity result data and the performance data of the polyurethane foam are shown in Table 4.

[0057] [Comparative Example 2]

[0058] In Comparative Example 1, the modified isocyanate used was commercially available Suprasec 2082, and its storage stability data is shown in Table 4; the modified isocyanate was formulated according to the foaming formula in Table 3, 100 g was taken for fluidity evaluation, and the remaining formula was foamed. The fluidity result data and the performance data of the polyurethane foam are shown in Table 4.

[0059] Table 4 Performance results of Examples 1 to 5 and Comparative Examples 1 to 2

[0060]

[0061] As can be seen from Table 4, the modified isocyanate in Examples 1 to 5 does not crystallize when stored at -15°C for 3 months, does not crystallize or bulge when stored at room temperature for 3 months, and does not crystallize when stored at 60°C for 72 hours, and the high and low temperature storage performance is better than that of Comparative Examples 1 to 2; in the fluidity evaluation experiment, the flow circumference of Examples 1 to 5 is 67.3 to 71.3 cm, and the fluidity is good; the tensile strength of the polyurethane foam obtained by foaming according to the molded foam formula is above 730 kPa, the elongation at break is above 250%, and the tear strength is above 12 N / cm, and the tensile and tearing properties are much better than those of Comparative Examples 1 to 2.

[0062] It can be seen that the modified isocyanate of the present invention has the advantages of stable storage, good fluidity, excellent tensile properties and tear properties of the prepared polyurethane foam, has achieved good technical effects, and can be used in industrial applications of polyurethane high resilience or self-skinning products.

Claims

1. A modified isocyanate, comprising, by weight: 11.3-92.1 parts of organic isocyanate, 0.3-17.2 parts of small molecule organic alcohol, 3.3-67.7 parts of polyether polyol, 50-500 ppm of antioxidant based on the total mass of raw materials, and 10-130 ppm of polymerization inhibitor based on the total mass of raw materials; wherein the organic isocyanate includes, by mass, 10-60 parts of 2,4-diphenylmethane diisocyanate, 20-70 parts of 4,4'-diphenylmethane diisocyanate Ester, 10 to 50 parts of carbodiimide modified isocyanate, and 5 to 35 parts of polymethylene polyphenyl isocyanate; the small molecule organic alcohol is selected from at least one of monoalcohol or diol; the average molecular weight of the polyether polyol is 450 to 2450, the functionality is 1 to 2.5, the EO mass percentage is 30 to 55%, the PO mass percentage is 60 to 75%, and the primary hydroxyl mass percentage is 30 to 60%; the antioxidant is selected from at least one of hindered phenol antioxidants, hindered amine antioxidants or phosphite antioxidants; the inhibitor is selected from at least one of acyl chlorides or acids; the mass percentage of isocyanate in the modified isocyanate is 16 to 32%; the relative molecular mass of the small molecule organic alcohol is 32 to 400, the monoalcohol is selected from at least one of ethanol, propanol, isopropanol, n-butanol, isobutanol, sec-butanol or n-pentanol; the diol is selected from 1, At least one of 2-butanediol, 1,4-butanediol, methyl propanediol, 1,2-propylene glycol, 1,3-propylene glycol, 1,3-butanediol, diethylene glycol, dipropylene glycol, diethylene glycol monobutyl ether, dipropylene glycol monomethyl ether or dipropylene glycol monobutyl ether; the acyl chloride is selected from at least one of benzoyl chloride, phenylacetyl chloride or adipoyl chloride; the acid is selected from at least one of phosphoric acid, polyphosphoric acid, adipic acid, citric acid, tartaric acid or p-toluenesulfonic acid.

2. The modified isocyanate according to claim 1, characterized in that The functionality of the polyether polyol is 1.2-2.0, the mass percentage of EO is 34-45%, the mass percentage of PO is 66-73%, and the mass percentage of primary hydroxyl is 40-45%; the organic isocyanate comprises, by mass, 12-23 parts of 2,4-diphenylmethane diisocyanate, 20-40 parts of 4,4'-diphenylmethane diisocyanate, 20-40 parts of carbodiimide modified isocyanate, and 7-19 parts of polymethylene polyphenyl isocyanate; the modified isocyanate comprises, by mass, 85-91.5 parts of organic isocyanate, 1.5-3 parts of small molecule organic alcohol, 5-27 parts of polyether polyol, 100-400 ppm of antioxidant based on the total mass of raw materials, and 10-130 ppm of inhibitor based on the total mass of raw materials.

3. A method for preparing the modified isocyanate according to claim 1, comprising the following steps: (1) Prepare the raw materials according to the following mass percentages: The composition comprises, by weight: 11.3 to 92.1 parts of organic isocyanate, 0.3 to 17.2 parts of small molecule organic alcohol, 3.3 to 67.7 parts of polyether polyol, 50 to 500 ppm of antioxidant based on the total weight of raw materials, and 10 to 130 ppm of polymerization inhibitor based on the total weight of raw materials; wherein the organic isocyanate comprises, by weight: 10 to 60 parts of 2,4-diphenylmethane diisocyanate, 20 to 70 parts of 4,4'-diphenylmethane diisocyanate, 10 to 50 parts of carbodiimide modified isocyanate, and 5 to 35 parts of polymethylene polyphenyl isocyanate; (2) Under the protection of a gas inert to the raw materials, the isocyanate monomer, the antioxidant, the small molecule organic alcohol and the polyether polyol are mixed to obtain material I; (3) Material I is subjected to a carbamate modification reaction at 55-90°C to obtain material II; (4) Sample material II for testing. When the mass percentage of isocyanate reaches 16-32%, add a polymerization inhibitor to inhibit the reaction of isocyanate with carbamate and urea, as well as the self-polymerization reaction of isocyanate, to obtain material III; (5) Lower the temperature of material III to 40-70°C and stir for 2-4 hours to terminate the reaction to obtain modified isocyanate.

4. The method for preparing the modified isocyanate according to claim 3, characterized in that: The temperature of the carbamate modification reaction is 75-85°C; when the mass percentage of isocyanate in material II reaches 16-19%, an inhibitor is added; the temperature of material III is reduced to 55-65°C, stirred for 2-4 hours, and the reaction is terminated.

5. Use of the modified isocyanate according to claim 1 in polyurethane high resilience or self-skinning products.

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