Amorphous hydrazide compound, preparation method thereof and polyurethane preparation method

Abstract

The invention provides an amorphous hydrazide compound and a preparation method thereof and a polyurethane preparation method, the structural formula of the amorphous hydrazide compound is # imgabs0 #, the amorphous hydrazide compound has large side chains (X and Y), the crystallinity of the amorphous hydrazide compound can be remarkably reduced, the amorphous hydrazide compound has medium and low temperature fluidity, and when the amorphous hydrazide compound is used as a chain extender for a polyurethane chain extension reaction, the content of the side chains is reduced, and the content of the side chains is reduced. The use of an organic solvent can be avoided, and meanwhile, reinforcing and toughening effects equivalent to those of a conventional hydrazide chain extender are achieved.

Description

Technical Field

[0001] The present invention relates to the field of chemical engineering technology, and specifically to an amorphous hydrazide compound, a preparation method thereof, and a preparation method of polyurethane. Background Art

[0002] In the current field of materials science, polyurethane, as a polymer material with excellent properties, is widely used in many industries, such as automotive manufacturing, construction, furniture, and shoe materials. However, the polyurethane prepared by the existing technology has deficiencies in strength and toughness, and it is difficult to meet the requirements of some high-end application scenarios with strict material performance requirements. Current research has confirmed that using a hydrazide chain extender in the chain extension reaction stage of polyurethane can significantly enhance the strength and toughness of the polyurethane elastomer by introducing the action of multiple hydrogen bonds. However, the high crystallinity of the hydrazide compound brings the problem of high melting point, and organic solvents need to be used as the reaction medium during the reaction. This approach has the following drawbacks: on the one hand, an additional process of evaporating the solvent must be added after the reaction, which undoubtedly slows down the efficiency of the entire production process compared with the casting method to obtain the polyurethane elastomer, increasing the time and energy costs; on the other hand, organic solvents generally have toxicity, which is not conducive to the physical health of operators, and pose a serious threat to the ecological environment during the subsequent product use and waste treatment processes, running counter to the current increasingly stringent environmental protection requirements. Summary of the Invention

[0003] To solve the above problems of the existing technology, the present invention provides an amorphous hydrazide compound, a preparation method thereof, and a preparation method of polyurethane. The hydrazide compound of the present invention has an amorphous structure and can be used as a chain extender without using organic solvents when synthesizing polyurethane for enhancing strength and toughness.

[0004] The present invention is achieved through the following technical solutions: In the first aspect, the present invention provides an amorphous hydrazide compound, and its structural formula is shown as formula (1):

[0005] Formula (1) Wherein, X and Y independently selected from H, n-pentyl, isopentyl, n-butyl, isobutyl, n-propyl, isopropyl, cyclohexyl and, n is an integer from 2 to 5, and X and Y are not both H at the same time.

[0006] Preferably, X and Y are H and isobutyl respectively, or X and Y are both H and isobutyl.

[0007] Furthermore, adding dimethyl disubstituted malonate shown in formula (2) to hydrazine hydrate and reacting under heating conditions, an amorphous hydrazide compound is obtained after the reaction ends;

[0008] Formula (2)

[0009] Furthermore, the molar ratio of the dimethyl disubstituted malonate to hydrazine hydrate is 1:(3 - 5).

[0010] Furthermore, the reaction temperature is 60 - 80 °C and the reaction time is 3 - 4 h.

[0011] Furthermore, after the reaction is completed, the liquid components of the obtained reaction system are rotary evaporated to obtain an amorphous hydrazide compound.

[0012] In a second aspect, the present invention provides a method for preparing a polyurethane, comprising:[[]] (1) Mixing an isocyanate and a polyol, adding a catalyst, and reacting to obtain a polyurethane prepolymer; (2) Adding the amorphous hydrazide compound according to claim 1 or 2 to the polyurethane prepolymer obtained in step (1), and heating for a chain extension reaction to obtain a polyurethane; or, adding the amorphous hydrazide compound according to claim 1 or 2 to the polyurethane prepolymer obtained in step (1), adding a solvent, heating for a chain extension reaction, and after the reaction is completed, removing the solvent to obtain a polyurethane.

[0013] Preferably, the isocyanate is one of IPDI, MDI, and TDI, the polyol is one of PTMG and PCL, and the catalyst is DBTDL. Preferably, the molar ratio of the amorphous hydrazide compound to the isocyanate is 1:(2 - 3).

[0014] Preferably, in step (2), the reaction temperature is 100 - 130 °C and the reaction time is 5 - 6 h.

[0015] Compared with the prior art, the present invention has the following beneficial effects: The amorphous hydrazide compound provided by the present invention has large side chains (X and Y), can significantly reduce its crystallinity, and endow it with medium and low temperature fluidity. When used as a chain extender in the polyurethane chain extension reaction, it can avoid the use of organic solvents, and at the same time has an equivalent reinforcing and toughening effect as conventional hydrazide chain extenders.

[0016] The present invention uses the amorphous hydrazide compound as a chain extender in the polyurethane chain extension reaction, which has an equivalent reinforcing and toughening effect as conventional hydrazide chain extenders, and at the same time can selectively add organic solvents, that is, organic solvents can be added or not added. When no organic solvent is added, it is more user - friendly for production and users, meets environmental protection standards, and can simplify the production process to achieve the purpose of cost reduction and efficiency increase. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the accompanying drawings required for the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0018] Figure 1 1H NMR spectrum of diisobutyl malonyl hydrazide prepared in the embodiment of the present invention.

[0019] Figure 2 Tensile test data graph of the polyurethane elastomer samples prepared in Comparative Example 1 and Example 6; Figure 3 Tensile test data graph of the polyurethane elastomer samples prepared in Comparative Examples 2, 3, 4 and Example 7. Detailed implementation manners

[0020] The following illustrates the embodiments of the present invention through specific specific examples. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific implementation manners. Various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.

[0021] It should be noted that the process equipment or devices not specifically noted in the following embodiments all adopt conventional equipment or devices in the art.

[0022] It should be noted that the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device including a series of steps or units does not necessarily have to be limited to those clearly listed steps or units, but may include other steps or units not clearly listed or inherent to these processes, methods, products or devices. Moreover, unless otherwise specified, the numbering of each method step is only a convenient tool for identifying each method step, rather than limiting the arrangement order of each method step or the scope in which the present invention can be implemented. The change or adjustment of their relative relationship, without substantial change in the technical content, should also be regarded as the scope in which the present invention can be implemented.

[0023] The amorphous hydrazide compounds provided by the present invention have the structural formula shown in Formula (1):

[0024] Formula (1) Wherein, X and Y are each independently selected from H, n-pentyl, isopentyl, n-butyl, isobutyl, n-propyl, isopropyl, cyclohexyl and short-chain siloxanyl groups, the short-chain siloxanyl group is , n is an integer from 2 to 5; X and Y can be the same or different, but not both H at the same time.

[0025] The hydrazide compounds of the present invention have large side chains, which can significantly reduce their crystallinity, obtain an amorphous form, have good low-temperature fluidity, and have an equivalent strengthening and toughening effect to conventional hydrazide chain extenders when used in polyurethane chain extension reactions. At the same time, the use of organic solvents can be avoided, which is more user-friendly for production and users, meets environmental protection standards, and can simplify the production process to achieve the purpose of cost reduction and efficiency increase.

[0026] The preparation method of the amorphous hydrazide compounds of the present invention is as follows: Dimethyl disubstituted malonate shown in formula (2) is added to hydrazine hydrate and reacted under heating conditions. After the reaction is completed, amorphous hydrazide compounds are obtained;

[0027] Formula (2) In the preparation method of the amorphous hydrazide compounds of the present invention, the molar ratio of dimethyl disubstituted malonate to hydrazine hydrate is 1:(3 - 5), the reaction temperature is 60 - 80 °C, and the reaction time is 3 - 4 h.

[0028] Using the amorphous hydrazide compounds of the present invention as a chain extender to prepare reinforced and toughened polyurethane, the preparation method includes: (1) Mix an isocyanate and a polyol, add a catalyst, and react to obtain a polyurethane prepolymer; (2) Add the amorphous hydrazide compounds as claimed in claim 1 or 2 to the polyurethane prepolymer obtained in step (1), and carry out a chain extension reaction by heating to obtain polyurethane; or, add the amorphous hydrazide compounds as claimed in claim 1 or 2 to the polyurethane prepolymer obtained in step (1), add a solvent, carry out a chain extension reaction by heating, and after the reaction is completed, remove the solvent to obtain polyurethane.

[0029] Because the hydrazide compounds of the present invention have an amorphous structure and have medium and low-temperature fluidity, when used as a chain extender, organic solvents can be added or not added. Not adding organic solvents is more environmentally friendly and can simplify the production process to achieve the purpose of cost reduction and efficiency increase.

[0030] In the above-mentioned preparation method of the polyurethane of the present invention, the isocyanate may be one of IPDI (Isophorone Diisocyanate), MDI (Methylene Diphenyl Diisocyanate), and TDI (Toluene Diisocyanate), the polyol may be one of PTMG (Polytetramethylene Ether Glycol) and PCL (Polycaprolactone), and the catalyst may be DBTDL (Dibutyltin Dilaurate).

[0031] In step (1) of the above-mentioned preparation method of the polyurethane of the present invention, the molar ratio of the polyol to the isocyanate is 1:(1.5 - 2), the reaction temperature is 80 - 100 °C, and the reaction time is 3 - 5 h.

[0032] In step (2) of the above-mentioned preparation method of the polyurethane of the present invention, the molar ratio of the amorphous hydrazide compound to the polyurethane prepolymer is 1:(2 - 3), the reaction temperature is 100 - 130 °C, and the reaction time is 5 - 6 h.

[0033] The amorphous hydrazide compound of the present invention can introduce multiple hydrogen bonds into the polyurethane, endowing it with excellent strength and toughness; this hydrazide compound has an amorphous structure and medium-low temperature fluidity, and can carry out chain extension of the polyurethane under solvent-free and non-high temperature conditions, thereby reducing or avoiding the use of organic solvents, simplifying the process, and improving efficiency.

[0034] Example 1 Weigh 3.76 g (20 mmol) of dimethyl isobutylmalonate (structure as shown in formula (3)) and 30.04 g (60 mmol) of hydrazine hydrate. Place the weighed dimethyl isobutylmalonate in a constant-pressure dropping funnel, and place the weighed hydrazine hydrate in a three-necked flask. Fix the three-necked flask on a magnetic stirrer, start stirring, heat it in an oil bath to 60 °C, and at the same time start the condenser reflux device. After the temperature of hydrazine hydrate in the three-necked flask stabilizes at 60 °C, open the valve of the constant-pressure dropping funnel, and drop dimethyl isobutylmalonate into the three-necked flask at a rate of 1 - 2 drops per second. After the dropping is complete, continue stirring and reacting at 60 °C for 3 h. After the reaction is completed, stop heating and stirring, transfer the reaction system to a rotary evaporator, set the vacuum degree to 0.1 MPa and the temperature to 50 °C, and rotary evaporate the liquid components to obtain isobutylmalonic dihydrazide, whose structure is as shown in formula (4).

[0035]

[0036] Formula (3)

[0037] Formula (4) Example 2 Weigh 5.44 g (20 mmol) of dimethyl diisobutylmalonate (structure as shown in Formula (5)) and 50.07 g (100 mmol) of hydrazine hydrate. Place the weighed dimethyl diisobutylmalonate in a constant-pressure dropping funnel, place the weighed hydrazine hydrate in a three-necked flask, fix the three-necked flask on a magnetic stirrer, heat it in an oil bath to 80 °C, and at the same time turn on the condenser reflux device. After the temperature of hydrazine hydrate in the three-necked flask is stabilized at 80 °C, open the valve of the constant-pressure dropping funnel, and drop dimethyl diisobutylmalonate into the three-necked flask at a rate of 1-2 drops per second. After the dropping is completed, continue to stir and react at 80 °C for 3 h. After the reaction is completed, stop heating and stirring, transfer the reaction system to a rotary evaporator, set the vacuum degree to 0.1 MPa and the temperature to 50 °C, and rotary evaporate the liquid components to obtain diisobutylmalonic dihydrazide, whose structure is as shown in Formula (6).

[0038]

[0039] Formula (5)

[0040] Formula (6) Example 6 Weigh 8 g (4 mmol) of vacuum-treated PTMG2000 and place it in a three-necked flask. Fix the three-necked flask on a magnetic stirrer, connect a vacuum pump and evacuate the air therein, introduce N2 gas, and then heat it in a protective oil bath to 100 °C. Add 1.779 g (8 mmol) of IPDI and 0.1 ml of catalyst DBTDL and mix and stir. Keep stirring and reacting at 100 °C for 5 h to obtain a polyurethane prepolymer. Then add 0.977 g (4 mmol) of diisobutylmalonic dihydrazide thereto, add 100 ml of ultra-dry dimethylacetamide, and then raise the heating temperature of the oil bath to 130 °C. Continue to stir and react for 6 h, then pour the product solution into a ultra-flat petri dish, and remove the solvent in a vacuum oven to obtain a polyurethane elastomer.

[0041] Example 7 Weigh 8 g (4 mmol) of vacuum-treated PTMG2000 and place it in a three-necked flask. Fix the three-necked flask on a magnetic stirrer, connect a vacuum pump and evacuate the air inside, then introduce N2 gas for protection. Heat it in an oil bath to 80 °C, add 1.334 g (6 mmol) of IPDI and 0.1 - 0.2 ml of catalyst DBTDL, mix and stir. Keep stirring at 80 °C for 3 h to obtain a polyurethane prepolymer. Then add 0.489 g (2 mmol) of diisobutyl malonyl dihydrazide to it. Raise the temperature of the oil bath to 100 °C and continue stirring and reacting for 5 h. Pour the product solution into a super-flat petri dish and cool it to room temperature to obtain a polyurethane elastomer.

[0042] Comparative Example 1 Weigh 8 g (4 mmol) of vacuum-treated PTMG2000 and place it in a three-necked flask. Fix the three-necked flask on a magnetic stirrer, connect a vacuum pump and evacuate the air inside, then introduce N2 gas. Heat it in an oil bath to 100 °C for protection. Add 1.779 g (8 mmol) of IPDI and 0.1 catalyst DBTDL, mix and stir. Keep stirring at 100 °C for 5 h to obtain a polyurethane prepolymer. Then add 0.776 g (4 mmol) of isophthaloyl dihydrazide to it, and add 100 ml of ultra-dry dimethylacetamide. Raise the temperature of the oil bath to 130 °C and continue stirring and reacting for 6 h. Pour the product solution into a super-flat petri dish and remove the solvent in a vacuum oven to obtain a polyurethane elastomer.

[0043] Comparative Example 2 Weigh 8 g (4 mmol) of vacuum-treated PTMG2000 and place it in a three-necked flask. Fix the three-necked flask on a magnetic stirrer, connect a vacuum pump and evacuate the air inside, then introduce N2 gas. Heat it in an oil bath to 80 °C for protection. Add 1.334 g (6 mmol) of IPDI and 0.1 - 0.2 ml of catalyst DBTDL, mix and stir. Keep stirring at 80 °C for 3 h to obtain a polyurethane prepolymer. Then add 0.388 g (2 mmol) of isophthaloyl dihydrazide to it. Raise the temperature of the oil bath to 100 °C and continue stirring and reacting for 5 h. Pour the product solution into a super-flat petri dish and cool it to room temperature to obtain a polyurethane elastomer.

[0044] Comparative Example 3 Weigh 8 g (4 mmol) of vacuum-treated PTMG2000 and place it in a three-necked flask. Fix the three-necked flask on a magnetic stirrer, connect a vacuum pump and evacuate the air inside, then introduce N2 gas for protection. Next, heat it in an oil bath to 80 °C, add 1.334 g (6 mmol) of IPDI and 0.1 ml of the catalyst DBTDL, and mix and stir. Keep stirring at 80 °C for 3 h to obtain a polyurethane prepolymer. Then add 0.18 g (2 mmol) of BDO (1,4-butanediol) to it, raise the temperature of the oil bath to 100 °C, and continue stirring and reacting for 5 h. After that, pour the product solution into a flat petri dish and cool it to room temperature to obtain a polyurethane elastomer.

[0045] Comparative Example 4 Weigh 8 g (4 mmol) of vacuum-treated PTMG2000 and place it in a three-necked flask. Fix the three-necked flask on a magnetic stirrer, connect a vacuum pump and evacuate the air inside, then introduce N2 gas for protection. Next, heat it in an oil bath to 80 °C, add 1.334 g (6 mmol) of IPDI and 0.1 ml of the catalyst DBTDL, and mix and stir. Keep stirring at 80 °C for 3 h to obtain a polyurethane prepolymer. Then add 0.264 g (2 mmol) of dihydrazide malonate to it, raise the temperature of the oil bath to 100 °C, and continue stirring and reacting for 5 h. After that, pour the product solution into a flat petri dish and cool it to room temperature to obtain a polyurethane elastomer.

[0046] Figure 1 1H NMR spectrum of diisobutyl dihydrazide malonate prepared in the example of the present invention.

[0047] Table 1 shows the melting points of each hydrazide compound obtained by heating. It can be seen from Table 1 that the melting points of dihydrazide malonate and isophthaloyl dihydrazide are higher than the temperature of the chain extension reaction, so they are not suitable for polyurethane synthesis under solvent-free conditions. However, the melting points of diisobutyl dihydrazide malonate and diisobutyl dihydrazide malonate are comparable to the temperature of the chain extension reaction. Therefore, polyurethane can be synthesized under solvent-free conditions.

[0048] Table 1 Melting points of each hydrazide compound

[0049] Figure 2 Figure of the tensile test data of the polyurethane elastomer samples prepared in Comparative Example 1 and Example 6. From Figure 2 it can be seen that under the condition of adding an organic solvent, the mechanical properties of the polyurethane elastomer prepared with diisobutyl dihydrazide malonate of the present invention are close to those of the polyurethane elastomer prepared with the conventional hydrazide chain extender isophthaloyl dihydrazide, indicating that the diisobutyl dihydrazide malonate of the present invention can be used as a hydrazide chain extender to prepare a reinforced and toughened polyurethane elastomer.

[0050] Figure 3 Tensile test data graphs of the polyurethane elastomer samples prepared in Comparative Examples 2, 3, 4, and Example 7. From Figure 3 It can be seen that without adding organic solvents, the polyurethane elastomer prepared with diisobutyl malonyl as the hydrazide chain extender in the present invention still has relatively high strength and toughness, while the strength and toughness of the polyurethane elastomers prepared with isophthaloyl hydrazide, BDO, and malonyl hydrazide as the hydrazide chain extenders are very poor. This shows that conventional hydrazide chain extenders need to prepare tough polyurethane elastomers under the condition of adding organic solvents, while the hydrazide compounds provided by the present invention can be used as chain extenders to prepare polyurethane elastomers with good mechanical properties without adding organic solvents.

Claims

1. An amorphous acylhydrazine compound, characterized in that, Its structural formula is shown in Formula (1): Formula (1) Wherein, X and Y are each independently selected from H, n-pentyl, isopentyl, n-butyl, isobutyl, n-propyl, isopropyl, cyclohexyl and, n is an integer from 2 to 5, and X and Y are not simultaneously H.

2. The amorphous hydrazide compound according to claim 1, wherein X and Y are H and isobutyl respectively, or both X and Y are H and isobutyl.

3. The preparation method of the amorphous hydrazide compound according to claim 1 or 2, characterized in that, The dimethyl disubstituted malonate shown in Formula (2) is added to hydrazine hydrate and reacted under heating conditions. After the reaction is completed, an amorphous hydrazide compound is obtained; Formula (2) 4. The preparation method of the amorphous hydrazide compound according to claim 3, characterized in that, The molar ratio of the dimethyl disubstituted malonate to hydrazine hydrate is 1:(3 - 5).

5. The preparation method of the amorphous hydrazide compound according to claim 3, wherein The reaction temperature is 60 - 80 °C, and the reaction time is 3 - 4 h.

6. The preparation method of the amorphous hydrazide compound according to claim 3, wherein, After the reaction is completed, the liquid components in the obtained reaction system are rotary evaporated to obtain an amorphous hydrazide compound.

7. A preparation method of polyurethane, characterized in that, Including: (1) Mix the isocyanate and the polyol, add a catalyst and react to obtain a polyurethane prepolymer; (2) Add the amorphous hydrazide compound described in Claim 1 or 2 to the polyurethane prepolymer obtained in step (1), and heat for chain extension reaction to obtain a polyurethane; or, add the amorphous hydrazide compound described in Claim 1 or 2 to the polyurethane prepolymer obtained in step (1), add a solvent, heat for chain extension reaction, and after the reaction is completed, remove the solvent to obtain a polyurethane.

8. The method for preparing polyurethane according to claim 7, characterized in that, The isocyanate is one of IPDI, MDI and TDI, the polyol is one of PTMG and PCL, and the catalyst is DBTDL.

9. The preparation method of the polyurethane according to claim 7, characterized in that, The molar ratio of the amorphous hydrazide compound to the isocyanate is 1:(2 - 3).

10. The preparation method of the polyurethane according to claim 7, characterized in that, In step (2), the reaction temperature is 100 - 130 °C, and the reaction time is 5 - 6 h.

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