Preparation method of bio-based binary primary alcohol capable of repairing damaged polyurethane

Abstract

The invention discloses a preparation method of bio-based binary primary alcohol capable of repairing damaged polyurethane, which is characterized in that furfural derivatives, carboxylic acid and isonitrile are used as raw materials, and the bio-based binary primary alcohol capable of repairing the damaged polyurethane is prepared through autocatalytic multi-component reaction. The method has the advantages of simplicity, mild reaction conditions, high yield and the like; the prepared bio-based diol has the advantages of high biochar content, high reaction activity and the like, and can be used for repairing damaged polyurethane.

Description

Technical Field

[0001] The invention relates to a method for preparing a bio-based primary diol capable of repairing damaged polyurethane, and belongs to the technical field of biomass-based materials. Background Art

[0002] As the fifth largest polymer material in the world, polyurethane is widely used in coatings, adhesives, sealants, elastomers and foams. In recent years, the design and preparation of functional polyurethane materials have attracted great research interest due to the ease of functional molecular chemical modification of its chain extenders, hard segments and soft segments. Among them, polyurethane materials with self-healing functions are particularly concerned. The characteristics of this material are that it can extend the service life of polyurethane, reduce resource waste and environmental pollution. At present, endogenous self-healing polyurethanes based on reversible dynamic covalent bonds have become the main research direction in the field of polyurethanes. Theoretically, polyurethane materials can achieve unlimited self-healing through the process of bond breaking and recombination. In this direction, predecessors have successfully used dynamic covalent chemical reactions such as Diels-Alder (DA) reaction, disulfide exchange reaction, borate exchange reaction and imine exchange reaction to achieve the repair of damaged polyurethane. It is particularly noteworthy that the DA reaction has attracted much attention due to its simplicity, high efficiency and few side reactions.

[0003] Up to now, there are relatively limited patents on bio-based diols for repairing damaged polyurethanes based on DA reactions. For example, Chinese patent CN112979919A uses a double aldehyde amine condensation method to prepare this type of bio-based diol. However, this method involves multiple steps in the preparation process, requires high temperature and a long reaction time. In addition, complex post-processing steps are required, and the yield is unstable. Therefore, how to efficiently prepare diols for self-repairing polyurethanes with high biocarbon content in a simpler way under mild reaction conditions is an urgent problem to be solved. Summary of the invention

[0004] The purpose of the present invention is to overcome the shortcomings and deficiencies of the prior art and to provide a method for preparing a bio-based primary diol that can repair damaged polyurethane. The bio-based primary diol that can be used to repair damaged polyurethane is prepared by an autocatalytic multi-component reaction using furfural derivatives, carboxylic acids and isonitriles as raw materials.

[0005] The present invention provides a method for preparing a bio-based primary diol capable of repairing damaged polyurethane, which is characterized by comprising the following steps: (1) Preparation of bio-based primary diols: Weigh 1 part adipic acid, 1.14 parts tert-butyl isocyanide and 1.73 parts 5 -HMF, and add 18 parts of solvent, keep at 35 oC was reacted for 20-24 h, and the crude product was obtained after rotary evaporation, and further purified by column chromatography to obtain the bio-based dihydric primary alcohol;

[0006] (2) Preparation of self-healing polyurethane: 1.36-1.64 parts of isophorone diisocyanate, 2.19-2.47 parts of polytetramethylene glycol with a molecular weight of 2000 and a small amount of organic bismuth catalyst were weighed and added into a three-necked flask equipped with a stirring rod and a thermometer, and reacted at 85 °C for 2 h; then, 0.3 parts of 1,4 -Butanediol continued to react for 2 h, and butanone was used to reduce its viscosity; then 0.41 parts of bio-based diol was added to the three-necked flask and continued to react for 4 h, followed by adding 41 parts of DMF to obtain a polyurethane solution with a theoretical solid content of 30%; finally, the reaction temperature was lowered to 60 °C, and 0.26 parts of diphenylmethane bismaleimide was added to the three-necked flask to undergo DA reaction for 24 h to obtain a self-healing polyurethane.

[0007] 2. A method for preparing a bio-based primary diol capable of repairing damaged polyurethane according to claim 1, characterized in that the aldehyde in the method is a small molecule hydroxyaldehyde based on renewable raw materials containing a furan ring, that is, 5- The molar ratio of hydroxymethylfurfural to carboxylic acid is 2, and the molar ratio of hydroxymethylfurfural to isonitrile is 1.

[0008] 3. The method for preparing a bio-based primary diol capable of repairing damaged polyurethane according to claim 1, characterized in that the solvent in the method is one or more of toluene, dichloromethane, and anhydrous ethanol.

[0009] Compared with the prior art, the present invention has the following obvious advantages: (1) Simple reaction steps: Through a self-catalytic multi-component reaction, the bio-based diol required to repair damaged polyurethane is generated in one step, avoiding the cumbersome multi-step reaction process.

[0010] (2) Mild reaction conditions and low energy consumption: The preparation process of the bio-based primary diol does not require additional catalysts and can be carried out at room temperature, so the reaction conditions are mild and the energy consumption is low.

[0011] (3) High product yield: The yield of the prepared bio-based diols can reach more than 95%, with high atom economy. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 This is the post-stress-strain curve of the polyurethane involved in the present invention before repair. DETAILED DESCRIPTION

[0013] The specific implementation methods of the present invention are further described below in conjunction with specific examples, but the present invention is not limited to the following examples. Unless otherwise specified, all raw materials used in the present invention can be purchased from the market. Example 1

[0014] (1) Preparation of bio-based primary diols: Weigh 1 part adipic acid, 1.14 parts tert-butyl isocyanide and 1.73 parts 5 -HMF, and add 18 parts of toluene, keep at 35 o C was reacted for 20-24 h, and the crude product was obtained after rotary evaporation, and further purified by column chromatography to obtain the bio-based dihydric primary alcohol;

[0015] (2) Preparation of self-healing polyurethane: 1.36 parts of isophorone diisocyanate, 2.19 parts of polytetramethylene glycol with a molecular weight of 2000 and a small amount of organic bismuth catalyst were weighed and added into a three-necked flask equipped with a stirring rod and a thermometer, and reacted at 85 °C for 2 h; then, 0.3 parts of 1,4 -Butanediol continued to react for 2 h, and butanone was used to reduce its viscosity; then 0.41 parts of bio-based diol was added to the three-necked flask and continued to react for 4 h, followed by adding 40 parts of DMF to obtain a polyurethane solution with a theoretical solid content of about 30%; finally, the reaction temperature was lowered to 60 °C, and 0.26 parts of diphenylmethane bismaleimide was added to the three-necked flask to undergo DA reaction for 24 h to obtain a self-healing polyurethane. Example 2

[0016] (1) Preparation of bio-based primary diols: Weigh 1 part adipic acid, 1.14 parts tert-butyl isocyanide and 1.73 parts 5 -Hydroxymethylfurfural, and add 18 parts of dichloromethane, keep at 35 o C was reacted for 20-24 h, and the crude product was obtained after rotary evaporation, and further purified by column chromatography to obtain the bio-based dihydric primary alcohol;

[0017] (2) Preparation of self-healing polyurethane: 1.5 parts of isophorone diisocyanate, 2.33 parts of polytetramethylene glycol with a molecular weight of 2000 and a small amount of organic bismuth catalyst were weighed and added into a three-necked flask equipped with a stirring rod and a thermometer, and reacted at 85 °C for 2 h; then, 0.3 parts of 1,4 -Butanediol continued to react for 2 h, and butanone was used to reduce its viscosity; then 0.41 parts of bio-based diol was added to the three-necked flask and continued to react for 4 h, followed by adding 40.5 parts of DMF to obtain a polyurethane solution with a theoretical solid content of about 30%; finally, the reaction temperature was lowered to 60 °C, and 0.26 parts of diphenylmethane bismaleimide was added to the three-necked flask to undergo DA reaction for 24 h to obtain a self-healing polyurethane. Example 3

[0018] (1) Preparation of bio-based primary diols: Weigh 1 part adipic acid, 1.14 parts tert-butyl isocyanide and 1.73 parts 5 -HMF, and add 18 parts of anhydrous ethanol, keep at 35 o C was reacted for 20-24 h, and the crude product was obtained after rotary evaporation, and further purified by column chromatography to obtain the bio-based dihydric primary alcohol;

[0019] (2) Preparation of self-healing polyurethane: 1.64 parts of isophorone diisocyanate, 2.47 parts of polytetramethylene glycol with a molecular weight of 2000 and a small amount of organic bismuth catalyst were weighed and added into a three-necked flask equipped with a stirring rod and a thermometer, and reacted at 85 °C for 2 h; then, 0.3 parts of 1,4 -Butanediol continued to react for 2 h, and butanone was used to reduce its viscosity; then 0.41 parts of bio-based diol was added to the three-necked flask and continued to react for 4 h, followed by adding 41 parts of DMF to obtain a polyurethane solution with a theoretical solid content of about 30%; finally, the reaction temperature was lowered to 60 °C, and 0.26 parts of diphenylmethane bismaleimide was added to the three-necked flask to undergo DA reaction for 24 h to obtain a self-healing polyurethane.

[0020] The molecular weight of the bio-based diol prepared by the above method is 564 g / mol. It has been verified that the polyurethane prepared by using it has a self-healing function with a repair efficiency of about 87%.

Claims

1. A method for preparing a bio-based primary diol capable of repairing damaged polyurethane, characterized in that The method comprises the following steps, wherein the materials used are by weight: (1) Preparation of bio-based primary diols: Weigh 1 part adipic acid, 1.14 parts tert-butyl isocyanide and 1.73 parts 5 -HMF, and add 18 parts of solvent, keep at 35 o C was reacted for 20-24 h, and the crude product was obtained after rotary evaporation, and further purified by column chromatography to obtain the bio-based dihydric primary alcohol; (2) Preparation of self-healing polyurethane: 1.36-1.64 parts of isophorone diisocyanate, 2.19-2.47 parts of polytetramethylene glycol with a molecular weight of 2000 and a small amount of organic bismuth catalyst were weighed and added into a three-necked flask equipped with a stirring rod and a thermometer, and reacted at 85 °C for 2 h; Then, add 0.3 parts 1,4 -Butanediol was allowed to react for 2 h, and butanone was used to reduce its viscosity; Next, 0.41 parts of bio-based diol were added to the three-necked flask and the reaction continued for 4 hours, followed by the addition of 40-41 parts of DMF to obtain a polyurethane solution with a theoretical solid content of approximately 30%. Finally, the reaction temperature was lowered to 60 °C, and 0.26 parts of diphenylmethane bismaleimide were added to the three-necked flask to undergo a Diels-Alder (DA) reaction for 24 hours to obtain a self-healing polyurethane.

2. The method for preparing a bio-based primary diol capable of repairing damaged polyurethane according to claim 1, characterized in that The aldehyde described in the method is a small molecule hydroxyaldehyde based on renewable raw materials containing a furan ring, namely 5- The molar ratio of hydroxymethylfurfural to carboxylic acid is 2, and the molar ratio of hydroxymethylfurfural to isonitrile is 1.

3. The method for preparing a bio-based primary diol capable of repairing damaged polyurethane according to claim 1, characterized in that The solvent described in the method is one or more of toluene, dichloromethane and anhydrous ethanol.

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