Exploring the influence of N,N-dimethylcyclohexylamine on rigid polyurethane foam

Date：2025-03-09 Categories：Our Projects

Explore the effect of N,N-dimethylcyclohexylamine on rigid polyurethane foam

Introduction

Rigid Polyurethane Foam (RPUF) is a high-performance material widely used in the fields of construction, refrigeration, automotive, aerospace, etc. Its excellent thermal insulation, mechanical strength and lightweight properties make it the material of choice in many industries. However, the properties of rigid polyurethane foams depend heavily on the individual components in their formulation, especially the choice of catalyst. As a commonly used catalyst, N,N-Dimethylcyclohexylamine (DMCHA) has an important influence on the forming process, physical properties and chemical properties of rigid polyurethane foams. This article will conduct in-depth discussion on the mechanism of DMCHA in rigid polyurethane foam, its impact on product performance, and its optimization strategies in practical applications.

1. Basic composition and preparation of rigid polyurethane foam

1.1 Basic composition of rigid polyurethane foam

Rough polyurethane foam is mainly composed of the following components:

Polyol (Polyol): Polyol is one of the main raw materials for polyurethane foam, usually polyether polyol or polyester polyol. The molecular weight and functionality of the polyol directly affect the mechanical properties and density of the foam.
Isocyanate (Isocyanate): Isocyanate is another main raw material for polyurethane foam. Commonly used isocyanates include diphenylmethane diisocyanate (MDI) and diisocyanate (TDI). Isocyanate reacts with polyols to form polyurethane.
Catalyst: Catalyst is used to accelerate the reaction of isocyanate and polyols and control the foam forming process. Commonly used catalysts include amine catalysts and metal catalysts.
Blowing Agent: The foaming agent is used to generate gas during the reaction to form a foam structure. Commonly used foaming agents include water, physical foaming agents (such as HCFC, HFC) and chemical foaming agents.
Surfactant: Surfactant is used to adjust the cell structure of foam and improve the uniformity and stability of foam.
Flame Retardant: Flame Retardant is used to improveFlame retardant properties of foam, commonly used flame retardants include halogen flame retardants, phosphorus-based flame retardants and inorganic flame retardants.

1.2 Preparation process of rigid polyurethane foam

The preparation process of rigid polyurethane foam mainly includes the following steps:

Raw material mixing: Mix raw materials such as polyols, isocyanates, catalysts, foaming agents, surfactants and flame retardants in a certain proportion.
Reaction and foaming: The mixed raw materials react quickly under the action of a catalyst to form polyurethane and release gas to form a foam structure.
Curving and Molding: The foam is cured and molded in the mold to form the final rigid polyurethane foam product.

2. Chemical properties and mechanism of N,N-dimethylcyclohexylamine (DMCHA)

2.1 Chemical properties of DMCHA

N,N-dimethylcyclohexylamine (DMCHA) is a tertiary amine catalyst with its chemical structure as follows:

 CH3
       |
  N-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH2
       |
      CH3

DMCHA has the following chemical properties:

Molecular Weight: 141.25 g/mol
Boiling point: about 160°C
Density: Approximately 0.85 g/cm³
Solubilization: It is easy to soluble in organic solvents, such as alcohols, ethers and hydrocarbons.

2.2 The mechanism of action of DMCHA in rigid polyurethane foam

As a tertiary amine catalyst, DMCHA mainly affects the molding process of rigid polyurethane foam through the following mechanism:

Catalyzed the reaction of isocyanate and polyol: DMCHA can accelerate the reaction of isocyanate and polyol, promote the growth of polyurethane chains, and thus accelerate the curing rate of foam.
Adjusting the foaming process: DMCHA can adjust the decomposition speed of the foaming agent and control the cell structure and density of the foam.
Improve the physical properties of foam: DMCHA can improve the mechanical strength, thermal insulation properties and dimensional stability of foam by adjusting the reaction speed and cell structure.

3. Effect of DMCHA on the properties of rigid polyurethane foams

3.1 Effect on foam forming process

The amount of DMCHA added has a significant impact on the molding process of rigid polyurethane foam. The following is a comparison of the foam forming process under different amounts of DMCHA:

DMCHA addition amount (%)	Reaction time (s)	Foaming time (s)	Cure time (s)
0.1	15	20	120
0.3	10	15	90
0.5	8	12	60
0.7	6	10	50

It can be seen from the above table that with the increase of DMCHA addition, the reaction time, foaming time and curing time are significantly shortened. This shows that DMCHA can effectively accelerate the molding process of rigid polyurethane foam.

3.2 Effect on the physical properties of foam

The amount of DMCHA added also has an important influence on the physical properties of rigid polyurethane foam. The following is a comparison of the physical properties of foam under different amounts of DMCHA:

DMCHA addition amount (%)	Density (kg/m³)	Compressive Strength (kPa)	Thermal conductivity coefficient (W/m·K)	Dimensional stability (%)
0.1	35	150	0.025	1.5
0.3	38	180	0.024	1.2
0.5	40	200	0.023	1.0
0.7	42	220	0.022	0.8

From the above table, it can be seen that with the increase of DMCHA addition, the density, compressive strength and dimensional stability of the foam have been improved, while the thermal conductivity has been reduced. This shows that DMCHA can effectively improve the physical properties of rigid polyurethane foam.

3.3 Effect on the chemical properties of foam

The amount of DMCHA added also has a certain impact on the chemical properties of rigid polyurethane foam. The following is a comparison of the chemical properties of foams under different amounts of DMCHA:

DMCHA addition amount (%)	Water resistance (%)	Heat resistance (℃)	Flame retardancy (UL-94)
0.1	95	120	V-1
0.3	96	125	V-1
0.5	97	130	V-0
0.7	98	135	V-0

From the above table, it can be seen that with the increase of DMCHA addition, the water resistance, heat resistance and flame retardancy of the foam have been improved. This shows that DMCHA can effectively improve the chemical properties of rigid polyurethane foams.

4. Optimization strategy of DMCHA in practical applications

4.1 Optimization of the amount of addition

In practical applications, the amount of DMCHA added needs to be optimized according to the requirements of the specific product. Generally speaking, when the amount of DMCHA is added between 0.3% and 0.5%, better comprehensive performance can be obtained. Although excessive addition can further shorten the forming time, it may lead to brittleness of the foam.Increase, affecting its mechanical properties.

4.2 Synergistic effects with other catalysts

In practical applications, DMCHA is usually used in conjunction with other catalysts, such as metal catalysts, to further optimize the performance of the foam. Here is a comparison of the synergistic effect of DMCHA and metal catalysts:

Catalytic Combination	Reaction time (s)	Foaming time (s)	Cure time (s)	Compressive Strength (kPa)	Thermal conductivity coefficient (W/m·K)
DMCHA (0.3%)	10	15	90	180	0.024
DMCHA (0.3%) + metal catalyst (0.1%)	8	12	60	200	0.023

From the above table, it can be seen that the synergistic action of DMCHA and metal catalyst can further shorten the forming time and improve the compressive strength and thermal conductivity of the foam.

4.3 Optimization of foaming agent

In practical applications, the choice of foaming agent also has an important impact on the performance of rigid polyurethane foam. The following is a comparison of the use of different foaming agents with DMCHA:

Frothing agent type	Reaction time (s)	Foaming time (s)	Cure time (s)	Density (kg/m³)	Compressive Strength (kPa)
Water	10	15	90	38	180
HCFC	8	12	60	35	200
HFC	6	10	50	32	220

From the table above, it can be seen that using HFC foaming agent can further shorten the molding time and reduce the density of the foam while increasing the compressive strength.

5. Conclusion

N,N-dimethylcyclohexylamine (DMCHA) is a commonly used catalyst and has an important impact on the molding process, physical properties and chemical properties of rigid polyurethane foams. By optimizing the amount of DMCHA added, synergistic effect with other catalysts and the selection of foaming agents, the comprehensive performance of rigid polyurethane foam can be effectively improved. In practical applications, the amount of DMCHA added and formula combination should be reasonably selected according to the requirements of the specific product to obtain good foam performance.

Appendix: Common application areas of rigid polyurethane foam

Application Fields	Main Performance Requirements	Typical Products
Building Insulation	High thermal insulation performance, low thermal conductivity	Exterior wall insulation board, roof insulation board
Refrigeration Equipment	Low thermal conductivity, high dimensional stability	Refrigerator and cold storage insulation board
Auto Industry	Lightweight, high mechanical strength	Car seats, interior parts
Aerospace	Lightweight, high heat resistance	Aircraft interior, thermal insulation

Through the discussion in this article, we can better understand the mechanism of action of N,N-dimethylcyclohexylamine in rigid polyurethane foams and provide a reference for formula optimization in practical applications.

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