Cyclohexylamine derivatives, methods of making and using the same, and polyurethane foams

Abstract

This invention relates to the field of polyurethane foam preparation technology, specifically to cyclohexylamine derivatives, their preparation methods, their applications, and polyurethane foam. The cyclohexylamine derivatives are selected from compounds with the following structural formula: [formula missing], wherein R1, R2, R3, R4, and R5 are independently selected from hydrogen or C1-C6 alkyl groups; m, n, p, and q are integers from 0 to 6; and X is OH or NH2. Cyclohexylamine derivatives themselves have a low amine odor, which can significantly improve the on-site operating environment during polyurethane foam processing and reduce the irritation of volatile substances to the operator's eyes and respiratory tract.

Description

Technical Field

[0001] This invention relates to the field of polyurethane foam preparation technology, and more specifically, to cyclohexylamine derivatives, their preparation methods and applications, and polyurethane foam. Background Technology

[0002] Polyurethane foam is a type of porous polymer material made primarily from polyols and isocyanates, through foaming and cross-linking polymerization reactions in the presence of foaming agents, silicone surfactants, catalysts, flame retardants, and other additives. It possesses characteristics such as lightweight, thermal insulation, cushioning, and flexible molding, making it one of the most widely used foam plastics. Organic amine catalysts are the core additives in polyurethane foam production, precisely controlling the reaction rate between polyols and water or isocyanates, balancing the foaming and gelation reactions, and ultimately determining the cell size, open / closed cell configuration, density, mechanical properties, and production efficiency of the polyurethane foam product.

[0003] Traditional organic amine catalysts (such as pentamethyldiethylenetriamine, triethylenediamine, etc.) have certain volatility and migration properties, resulting in significant odor residue and VOC release problems in polyurethane foam production. This not only affects the production environment and the user experience of end products, but is also subject to strict environmental regulations. This is the core pain point restricting the application of polyurethane foam in low-odor scenarios such as indoor spaces and automotive interiors.

[0004] In view of this, the present invention is proposed. Summary of the Invention

[0005] The purpose of this invention is to provide cyclohexylamine derivatives, their preparation methods, their applications, and polyurethane foam. One embodiment of this invention provides a cyclohexylamine derivative with a low amine odor, which can significantly improve the on-site operating environment during polyurethane foam processing and reduce the irritation of volatile substances to the operator's eyes and respiratory tract.

[0006] This invention is implemented as follows: In a first aspect, the present invention provides a cyclohexylamine derivative selected from compounds shown in the following structural formulas: In this context, R1, R2, R3, R4, and R5 are each independently selected from hydrogen or C1-C6 alkyl groups; m, n, p, and q are integers from 0 to 6; and X is OH or NH2.

[0007] In an optional embodiment, R1, R2, R3, R4 and R5 are each independently selected from hydrogen or C1-C3 alkyl; preferably any one of methyl, ethyl or isopropyl.

[0008] In an optional embodiment, it is selected from any of the compounds shown in the following structural formulas: and .

[0009] Secondly, the present invention provides a method for preparing the cyclohexylamine derivatives described in the foregoing embodiments, comprising: synthesizing according to the following synthetic route: The raw material containing the N-alkylcyclohexylamine structure is mixed with an epoxide to carry out a ring-opening reaction.

[0010] Thirdly, the present invention provides an application of the cyclohexylamine derivatives described in the foregoing embodiments in the preparation of polyurethane foam.

[0011] In an optional embodiment, the cyclohexylamine derivative is used as a catalyst in the preparation of polyurethane foam.

[0012] Fourthly, the present invention provides a polyurethane foam comprising the cyclohexylamine derivatives described in the foregoing embodiments.

[0013] In an optional embodiment, it also includes an organosilicon surfactant.

[0014] In an optional embodiment, it also includes a polyisocyanate.

[0015] In an optional embodiment, it also includes a polyether polyol.

[0016] The present invention has the following beneficial effects: (1) The present invention provides a cyclohexylamine derivative, which can be applied to the formulation of polyurethane foam. It can better catalyze the reaction between isocyanate and water or polyol, and can match different production processes of related polyurethane foam. The final polyurethane foam product has the characteristics of low odor and low VOC emission, which helps downstream market customers meet the environmental protection performance requirements.

[0017] (2) The cyclohexylamine derivatives provided in the embodiments of the present invention have a low amine odor, which can significantly improve the on-site operating environment during the polyurethane foam processing and reduce the irritation of volatiles to the operator's eyes and respiratory tract. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0019] In a first aspect, embodiments of the present invention provide a cyclohexylamine derivative selected from compounds shown in the following structural formulas: R1, R2, R3, R4, and R5 are each independently selected from hydrogen or C1-C6 alkyl groups; for example, they are branched or straight-chain alkyl groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, and tert-butyl, preferably hydrogen or C1-C3 alkyl groups. m, n, p, and q are integers from 0 to 6; for example, they are any values ​​between 0 and 6, such as 0, 1, 2, 3, 4, 5, and 6, preferably any values ​​between 1 and 4. X is OH or NH2.

[0020] Furthermore, it is selected from any one of the compounds shown in the following structural formulas. (N-methyl-N-hydroxyethylcyclohexylamine) and (N-methyl-N-hydroxyisopropylcyclohexylamine).

[0021] Secondly, embodiments of the present invention also provide a method for preparing the above-mentioned cyclohexylamine derivatives, which is synthesized according to the following synthetic route: A ring-opening reaction is carried out by mixing a raw material containing an N-alkylcyclohexylamine structure (such as N-methylcyclohexylamine) with an epoxide (such as ethylene oxide or propylene oxide).

[0022] This invention uses N-methyl-N-hydroxyethylcyclohexylamine as an example for synthesis. The specific operation process is as follows: Under the protection of an inert gas (e.g., nitrogen), N-methylcyclohexylamine is added to a high-pressure reactor. After being purged three times with an inert gas (e.g., nitrogen), stirring is started, and the temperature is raised to 60-80°C and stabilized. Ethylene oxide is slowly introduced through a metering device, strictly controlling the reaction temperature not to exceed 85°C and the pressure inside the reactor not to exceed 0.30 MPa. The introduction process continues for 2-4 hours, and then the reaction is maintained at 70-80°C for 3-5 hours until the reactor pressure becomes constant and no longer decreases, which is considered the reaction endpoint. Subsequently, the temperature is cooled to below 20-40°C, the pressure is slowly released, and the reactor is purged with low-flow nitrogen for 10-20 minutes to completely remove residual ethylene oxide, obtaining crude N-methyl-N-hydroxyethylcyclohexylamine, which can be further purified by vacuum distillation.

[0023] Thirdly, embodiments of the present invention provide the application of the above-mentioned cyclohexylamine derivatives in the preparation of polyurethane foam. Specifically, when the cyclohexylamine derivatives are used as catalysts for polyurethane (e.g., rigid polyurethane foam, flexible polyurethane foam, molded high-resilience polyurethane foam, and sprayed polyurethane foam), they can further reduce the odor of the catalyst itself and the odor and VOC emissions of polyurethane foam products.

[0024] Fourthly, embodiments of the present invention provide a polyurethane foam comprising the above-mentioned cyclohexylamine derivatives.

[0025] Furthermore, it also includes polyisocyanates, such as polymeric MDI (also known as PAPI, which is a mixture of 4,4'-diphenylmethane diisocyanate (MDI) and polyphenyl ring polyisocyanates with a functionality greater than 2), toluene diisocyanate (TDI, often a mixture of 2,4-isomers and 2,6-isomers in a certain proportion), isophorone diisocyanate (IPDI), hexamethylene diisocyanate (HDI), diphenylmethane diisocyanate (MDI), and other conventional polyisocyanates, used alone or in a certain proportion. It can also be isocyanate derivatives that have undergone structural modification or composite modification of basic isocyanates (such as TDI, MDI, HDI, etc.) through chemical or physical means.

[0026] Furthermore, the amount of polyisocyanate used is of existing choice, for example, the mass ratio of the polyisocyanate to the cyclohexylamine derivative is 148:(1-11); for example, any value between 148:(1-11) such as 148:1, 148:2, 148:4, 148:5, 148:8, 148:10, 148:11, etc.

[0027] It also includes polyether polyols; for example, polyether polyols can be prepared by reacting sucrose, glycerol, polyether glycol, sorbitol, etc., with ethylene oxide or propylene oxide as initiators; polyester polyols can be prepared by polycondensation reactions of dicarboxylic acids (such as adipic acid or sebacic acid) or polyacid anhydrides (such as phthalic anhydride or maleic anhydride) with diols (such as ethylene glycol or 1,4-butanediol) or triols (such as glycerol, with functionality adjusted); vegetable oil-based polyols can be prepared by modifying natural oils such as castor oil or soybean oil through epoxidation, hydroxylation, etc.; and grafted polyether polyols (commonly known as polymer polyols, or POP for short). The selection and combination of polyol compounds with different properties helps polyurethane foam achieve better overall performance.

[0028] Furthermore, the amount of polyether polyol used is of existing choice, for example, the mass ratio of polyether polyol to the cyclohexylamine derivative is 100:(1-4). For example, it is any value between 100:(1-4), such as 100:1, 100:2, 100:3, 100:4, etc.

[0029] Furthermore, it also includes silicone surfactants, with the appropriate commercial products selected based on the specific polyurethane foam application. Examples include MAYSTA® M88310 (for rigid foam appliance systems), MAYSTA® M88313 (for rigid foam continuous sheet systems), MAYSTA® M88207 (for rigid foam spraying systems), MAYSTA® M6688LVN (for flexible foam systems), and MAYSTA® M7715LF2 (for molding high-resilience systems).

[0030] Furthermore, the amount of silicone surfactant used is of existing choice, for example, the mass ratio of silicone surfactant to the cyclohexylamine derivative is 2:(1-12). For example, it is any value between 2:(1-12), such as 2:1, 2:2, 2:5, 2:7, 2:8, 2:10, 2:11, 2:12, etc.

[0031] Furthermore, it also includes flame retardants, such as organophosphorus compounds like tri(1-chloro-2-propyl)phosphate (TCPP) or triethyl phosphate (TEP), which can be used alone or in combination.

[0032] Furthermore, it also includes chemical foaming agents, such as water.

[0033] Furthermore, it also includes physical foaming agents, such as hydrocarbon compounds like n-pentane, cyclopentane, and isopentane, dichloromethane, hydrofluoroalkanes (HFCs), and hydrofluoroolefins (HFOs).

[0034] In this embodiment of the invention, the VDA 278: 05 / 2016 thermal desorption analysis standard is used to conduct a semi-quantitative assessment of the organic VOC emissions of polyurethane foam samples.

[0035] The features and performance of the present invention will be further described in detail below with reference to embodiments.

[0036] Example 1 and Comparative Example 1 Example 1 and Comparative Example 1 provide a polyurethane foam. The components forming the polyurethane foam are shown in Table 1. The polyurethane foam was tested. Specifically, free foaming was performed at room temperature (22±2℃), and free foam data such as milky white time and gel time were observed. The catalytic activity of different organic amine catalysts was evaluated by comparing the foaming and gel times of different organic amine catalysts at the same addition amount, or by comparing the addition amounts of different organic amine catalysts when gel times were similar. The catalytic tendency of different organic amine catalysts was evaluated by comparing the foaming time with the gel time. The results are shown in Table 1.

[0037] Table 1. Test results of polyurethane foam composition and performance.

[0038] N-Methyl-N-hydroxyethylcyclohexylamine exhibits certain catalytic activity in rigid polyurethane foams, tending towards gelation, and can be used as a catalyst in polyurethane systems. At room temperature, the odor of N-methyl-N-hydroxyethylcyclohexylamine is significantly lower than that of conventional MAYCAT® 808 organic amine catalysts.

[0039] The synthetic route of N-methyl-N-hydroxyethylcyclohexylamine is as follows: Under nitrogen protection, 113.2 g of N-methylcyclohexylamine was added to a high-pressure reactor. After purging with nitrogen three times, stirring was started, and the temperature was raised to 75°C and stabilized. 46.3 g of ethylene oxide was slowly introduced through a metering device, strictly controlling the reaction temperature to not exceed 85°C and the reactor pressure to not exceed 0.30 MPa. The introduction process continued for 3 hours, followed by holding the reaction at 80°C for 4 hours until the reactor pressure stabilized and no longer decreased, which was considered the reaction endpoint. The reactor was then cooled to below 35°C, slowly depressurized, and purged with low-flow nitrogen for 15 minutes to completely remove residual ethylene oxide, yielding crude N-methyl-N-hydroxyethylcyclohexylamine, which can be further purified by vacuum distillation.

[0040] Examples 2-3 and Comparative Example 2 Examples 2-3 and Comparative Example 2 provide a polyurethane foam. The composition of the polyurethane foam is shown in Table 2. The polyurethane foam was tested, and the test results are shown in Table 2.

[0041] Table 2. Test results of polyurethane foam composition and performance.

[0042] As shown in Table 2, N-methyl-N-aminoethylcyclohexylamine has the highest catalytic activity, but its amine odor is also slightly stronger than that of N-methyl-N-hydroxyethylcyclohexylamine or N-methyl-N-hydroxyisopropylcyclohexylamine.

[0043] Example 4 and Comparative Examples 3-4 Example 4 and Comparative Examples 3-4 provide a polyurethane foam. The composition of the polyurethane foam is shown in Table 3. The polyurethane foam was tested by box-type foaming at room temperature (22±2℃). The foaming process, including foaming time, final rising height, and falling height, was observed. The physical properties of the foam product were tested. The test results are shown in Table 3.

[0044] Table 3. Test results of polyurethane foam composition and performance.

[0045] As shown in Table 3, both N-methyl-N-hydroxyethylcyclohexylamine and N-methyl-N-aminoethylcyclohexylamine exhibit certain catalytic activity in flexible foam formulations, resulting in normal foam expansion. They can replace conventional MAYCAT® 633 organic amine catalysts in polyurethane flexible foam systems. Foam samples prepared with N-methyl-N-aminocyclohexylamine show normal foam properties and exhibit the lowest VOC emissions.

[0046] Example 5 and Comparative Example 5 Example 5 and Comparative Example 5 provide a polyurethane foam. The composition of the polyurethane foam is shown in Table 4. The polyurethane foam was tested, and the test results are shown in Table 4.

[0047] Table 4. Test results of polyurethane foam composition and performance.

[0048] As shown in Table 4, the free bubble data after N-methyl-N-hydroxyethylcyclohexylamine partially replaced MAYCAT® 806 remained basically unchanged, but the odor of the compound itself and during foaming was significantly reduced, which can greatly improve the on-site environment during polyurethane foam spraying.

[0049] Example 6 and Comparative Example 6 Example 6 and Comparative Example 6 provide a polyurethane foam. The composition of the polyurethane foam is shown in Table 5. The polyurethane foam was tested, and the test results are shown in Table 5.

[0050] Table 5. Test results of polyurethane foam composition and performance.

[0051] As shown in Table 5, N-methyl-N-hydroxyethylcyclohexylamine exhibits good catalytic activity in molding formulations, with normal foaming in the mold. It can be used as a catalyst in high-resilience polyurethane molding systems. The foam samples prepared with N-methyl-N-hydroxyethylcyclohexylamine show normal foam properties and lower odor and VOC emissions.

[0052] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A cyclohexylamine derivative, characterized in that, It is selected from compounds with the following structural formulas: In this context, R1, R2, R3, R4, and R5 are each independently selected from hydrogen or C1-C6 alkyl groups; m, n, p, and q are integers from 0 to 6; and X is OH or NH2.

2. The cyclohexylamine derivative according to claim 1, characterized in that, R1, R2, R3, R4 and R5 are each independently selected from hydrogen or C1-C3 alkyl groups; preferably any one of methyl, ethyl or isopropyl.

3. The cyclohexylamine derivative according to claim 1, characterized in that, It is selected from any one of the compounds shown in the following structural formulas: and .

4. A method for preparing the cyclohexylamine derivative according to claim 1, characterized in that, include: Perform the synthesis according to the following synthesis path: The raw material containing the N-alkylcyclohexylamine structure is mixed with an epoxide to carry out a ring-opening reaction.

5. The use of the cyclohexylamine derivative of claim 1 in the preparation of polyurethane foam.

6. The application according to claim 5, characterized in that, The application of cyclohexylamine derivatives as catalysts in the preparation of polyurethane foam.

7. A polyurethane foam, characterized in that, It includes the cyclohexylamine derivatives as described in claim 1.

8. The polyurethane foam according to claim 7, characterized in that, It also includes organosilicon surfactants.

9. The polyurethane foam according to claim 7, characterized in that, It also includes polyisocyanates.

10. The polyurethane foam according to claim 7, characterized in that, It also includes polyether polyols.

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