Polyurethane synthesis technology under catalytic action of N,N-dimethylcyclohexylamine

Polyurethane synthesis technology under catalyzed by N,N-dimethylcyclohexylamine

1. Introduction

Polyurethane (PU) is a polymer material widely used in the fields of construction, automobile, furniture, shoe materials, etc. Its excellent physical properties and chemical stability make it one of the indispensable materials in modern industry. In the synthesis of polyurethane, the selection of catalyst is crucial. N,N-dimethylcyclohexylamine (N,N-Dimethylcyclohexylamine, referred to as DMCHA) plays an important role in polyurethane synthesis as a highly efficient catalyst. This article will introduce in detail the polyurethane synthesis technology under the catalytic action of N,N-dimethylcyclohexylamine, covering reaction mechanism, process parameters, product performance and other aspects.

2. Chemical properties of N,N-dimethylcyclohexylamine

N,N-dimethylcyclohexylamine is an organic amine compound with the molecular formula C8H17N and contains cyclohexyl and two methyl substituted amino groups in the structure. Its chemical properties are as follows:

Features	Value/Description
Molecular Weight	127.23 g/mol
Boiling point	159-160 °C
Density	0.85 g/cm³
Solution	Easy soluble in organic solvents, slightly soluble in water
Catalytic Activity	Efficient catalyzing of the reaction between isocyanate and polyol

3. Basic principles of polyurethane synthesis

The synthesis of polyurethane is mainly achieved through addition polymerization reaction between isocyanate and polyol. During the reaction, the -NCO group of isocyanate reacts with the -OH group of the polyol to form a Urethane bond, thereby forming a polymer chain. The reaction equation is as follows:

R-NCO + R'-OH → R-NH-CO-O-R'

Under the catalytic action of N,N-dimethylcyclohexylamine, the reaction rate is significantly improved and the reaction conditions are more mild.

4. Catalytic mechanism of N,N-dimethylcyclohexylamine

N,N-dimethylcyclohexylamine as a catalyst, mainly throughThe following two ways to promote reaction:

Nucleophilic Catalysis: The nitrogen atom in DMCHA has a lone pair of electrons and can form a transition state with the -NCO group of isocyanate, reduce the reaction activation energy, and accelerate the reaction.
Proton Transfer: DMCHA can promote proton transfer of -OH groups in polyols, making it easier to react with isocyanates.

5. Polyurethane synthesis process

5.1 Raw material preparation

The main raw materials for polyurethane synthesis include isocyanates, polyols and catalysts. The specific raw material parameters are as follows:

Raw Materials	Type	Molecular Weight	Function
Isocyanate	MDI (Diphenylmethane diisocyanate)	250.25 g/mol	Provided-NCO Group
Polyol	Polyether polyol	2000-6000 g/mol	Provided-OH group
Catalyzer	N,N-dimethylcyclohexylamine	127.23 g/mol	Accelerating the reaction

5.2 Reaction conditions

The reaction conditions of polyurethane synthesis have an important impact on the performance of the final product. The following are typical reaction conditions:

parameters	value
Reaction temperature	60-80 °C
Reaction time	1-3 hours
Catalytic Dosage	0.1-0.5 wt%
Isocyanate to polyol ratio	1:1 (molar ratio)

5.3 Process flow

Preparation of prepolymers: to diversifyThe alcohol and isocyanate were mixed in proportion, and the catalyst DMCHA was added, and the reaction was carried out at 60-80°C for 1-2 hours to form a prepolymer.
Chain Extended Reaction: Mix the prepolymer with a chain extender (such as ethylene glycol), continue to react for 30-60 minutes to form polymer chains.
Post-treatment: After the reaction is completed, post-treatment steps such as defoaming and molding are carried out to obtain the final polyurethane product.

6. Product Performance

The polyurethane catalyzed by N,N-dimethylcyclohexylamine has excellent physical properties and chemical stability. The following are typical product performance parameters:

Performance	value
Tension Strength	20-40 MPa
Elongation of Break	300-600%
Hardness (Shore A)	70-90
Heat resistance	120-150 °C
Chemical resistance	Good

7. Application areas

Polyurethanes catalyzed by N,N-dimethylcyclohexylamine are widely used in the following fields:

Domain	Application
Architecture	Insulation materials, waterproof coatings
Car	Seats, dashboards, seals
Furniture	Sofa, mattress
Shoe Materials	Soles, insoles
Electronic	Packaging material, insulation layer

8. Process Optimization

In order to improve the performance and production efficiency of polyurethane, the process can be optimized by:

Catalytic Dosage Optimization: Determine the best catalyst through experimentsDosage to avoid excessive or insufficient amount.
Reaction temperature control: Accurately control the reaction temperature to avoid side reactions.
Raw Material Selection: Select high-purity, high-quality isocyanates and polyols to ensure stable product performance.

9. Environmental protection and safety

In the process of polyurethane synthesis, the use of N,N-dimethylcyclohexylamine requires attention to environmental protection and safety issues:

Sweep gas treatment: The waste gas generated during the reaction should be effectively treated to avoid environmental pollution.
Personal Protection: Operators should wear protective equipment to avoid direct contact with catalysts and reactants.
Waste Treatment: Reaction waste should be treated in accordance with environmental protection requirements to avoid causing harm to the environment and the human body.

10. Conclusion

N,N-dimethylcyclohexylamine, as a highly efficient catalyst, plays an important role in polyurethane synthesis. Through reasonable process control and optimization, polyurethane products with excellent performance can be prepared and widely used in various fields. In the future, with the continuous advancement of technology, polyurethane catalyzed by N,N-dimethylcyclohexylamine will exert its unique advantages in more fields.

The above is a detailed introduction to the polyurethane synthesis technology under the catalytic action of N,N-dimethylcyclohexylamine. Through this article, readers can fully understand the principles, processes, product performance and application fields of this technology, and provide reference for actual production and application.