Methods for N,N-dimethylcyclohexylamine to improve the durability of polyurethane coating
Introduction
Polyurethane coatings are widely used in construction, automobile, ship, furniture and other fields due to their excellent mechanical properties, chemical resistance and weather resistance. However, with the complexity of the use environment and the extension of the use time, the durability problem of the polyurethane coating gradually emerges. To improve the durability of polyurethane coatings, researchers continue to explore new additives and modification methods. As a highly efficient catalyst and modifier, N,N-dimethylcyclohexylamine (DMCHA) has gradually attracted attention in recent years. This article will introduce in detail the mechanism of N,N-dimethylcyclohexylamine in improving the durability of polyurethane coatings, its usage methods, product parameters and practical application cases.
I. Basic properties of N,N-dimethylcyclohexylamine
1.1 Chemical structure
N,N-dimethylcyclohexylamine (DMCHA) is an organic amine compound with its chemical structure as follows:
CH3
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N-CH3
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/
/
| |
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/
/
/
C1.2 Physical Properties
| Properties | value |
|---|---|
| Molecular formula | C8H17N |
| Molecular Weight | 127.23 g/mol |
| Boiling point | 160-162°C |
| Density | 0.85 g/cm³ |
| Flashpoint | 40°C |
| Solution | Easy soluble in organic solvents |
1.3 Chemical Properties
N,N-dimethylcyclohexylamine has strong basicity and can react with acid to form salts. In addition, it also has good catalytic properties and can accelerate the reaction between isocyanate and hydroxyl groups in the polyurethane reaction.
2. The mechanism of action of N,N-dimethylcyclohexylamine in polyurethane coating
2.1 Catalysis
N,N-dimethylcyclohexylamine, as a highly efficient catalyst, can significantly accelerate the reaction between isocyanate and hydroxyl groups in the polyurethane reaction. The catalytic mechanism is as follows:
- Activated isocyanate: The nitrogen atom in N,N-dimethylcyclohexylamine has a lone pair of electrons and can form coordination bonds with the carbon atoms in the isocyanate to activate isocyanate.
- Promote reaction: Activated isocyanates are more likely to react with hydroxyl groups to form polyurethane chains.
2.2 Modification effect
N,N-dimethylcyclohexylamine not only has a catalytic effect, but also can modify the polyurethane coating by cyclohexyl groups in its molecular structure. The specific functions are as follows:
- Improving Crosslinking Density: N,N-dimethylcyclohexylamine can react with isocyanate groups in the polyurethane chain to form a crosslinking structure, thereby increasing the crosslinking density of the coating.
- Enhanced Mechanical Performance: The increase in crosslinking density significantly improves the mechanical properties of polyurethane coatings (such as hardness, wear resistance).
- Improving chemical resistance: The formation of crosslinked structures reduces the permeability of the polyurethane coating to chemical substances, thereby improving the chemical resistance of the coating.
III. Methods for using N,N-dimethylcyclohexylamine
3.1 Addition amount
The amount of N,N-dimethylcyclohexylamine added has a significant impact on the performance of the polyurethane coating. Generally speaking, it is more appropriate to add between 0.1% and 1.0%. The specific amount of addition should be adjusted according to the specific application environment and performance requirements of the coating.
| Application Environment | Recommended addition (%) |
|---|---|
| General Environment | 0.1-0.3 |
| High humidity environment | 0.3-0.5 |
| High chemical corrosion environment | 0.5-1.0 |
3.2 Adding method
N,N-dimethylcyclohexylamine can be added to the polyurethane coating in two ways:
- Direct addition: Add N,N-dimethylcyclohexylamine directly to the polyurethane prepolymer, stir evenly and then coat.
- Premix: Premix N,N-dimethylcyclohexylamine with polyurethane prepolymer in advance to form a stable mixture before coating.
3.3 Notes
- Storage conditions: N,N-dimethylcyclohexylamine should be stored in a cool and dry environment to avoid contact with acids.
- Safe Operation: N,N-dimethylcyclohexylamine has a certain irritation. Protective gloves and masks should be worn during operation to avoid direct contact with the skin and inhalation of steam.
IV. Practical application cases of N,N-dimethylcyclohexylamine to improve the durability of polyurethane coating
4.1 Building exterior wall coating
In building exterior paints, polyurethane coatings need to have excellent weather resistance and chemical resistance. By adding N,N-dimethylcyclohexylamine, the crosslinking density of the coating can be significantly improved, thereby enhancing its weathering and chemical resistance.
| Performance metrics | DMCHA not added | Add DMCHA (0.3%) |
|---|---|---|
| Weather resistance (hours) | 1000 | 1500 |
| Chemical resistance (grade) | 3 | 5 |
4.2 Automotive Paint
Auto paints need to have excellent wear resistance and corrosion resistance. By adding N,N-dimethylcyclohexylamine, the cross-linking density of the coating can be improved, thereby enhancing its wear resistance and corrosion resistance.
| Performance metrics | DMCHA not added | Add DMCHA (0.5%) |
|---|---|---|
| Abrasion resistance (times) | 500 | 800 |
| Corrosion resistance (grade) | 4 | 6 |
4.3 Marine coating
Marine coatings need to have excellent water resistance and salt spray resistance. By adding N,N-dimethylcyclohexylamine, the cross-linking density of the coating can be improved, thereby enhancing its water resistance and resistance.Salt spray.
| Performance metrics | DMCHA not added | Add DMCHA (0.7%) |
|---|---|---|
| Water resistance (hours) | 500 | 1000 |
| Salt spray resistance (grade) | 3 | 5 |
V. Product parameters of N,N-dimethylcyclohexylamine
5.1 Product Specifications
| parameters | value |
|---|---|
| Appearance | Colorless transparent liquid |
| Purity | ≥99% |
| Moisture | ≤0.1% |
| Acne | ≤0.1 mg KOH/g |
| Flashpoint | 40°C |
| Packaging | 25kg/barrel |
5.2 Product Advantages
- High-efficiency Catalysis: N,N-dimethylcyclohexylamine has efficient catalytic properties and can significantly accelerate the polyurethane reaction.
- Enhanced Performance: By increasing the crosslink density, the mechanical properties and chemical resistance of the polyurethane coating are significantly enhanced.
- Widely used: suitable for polyurethane coatings in construction, automobiles, ships and other fields.
VI. Conclusion
N,N-dimethylcyclohexylamine, as a highly efficient catalyst and modifier, plays a significant role in improving the durability of polyurethane coatings. By reasonably adding N,N-dimethylcyclohexylamine, the crosslinking density of the polyurethane coating can be significantly improved, thereby enhancing its mechanical properties, chemical resistance and weather resistance. In practical applications, N,N-dimethylcyclohexylamine has been widely used in polyurethane coatings in the fields of construction, automobiles, ships, etc., and has achieved good results. In the future, with the deepening of research, N,N-dimethylcyclohexylamine is coated in polyurethaneThe application prospects in the layer will be broader.
7. Appendix
7.1 FAQ
Q1: How to determine the amount of N,N-dimethylcyclohexylamine added?
A1: The amount of N,N-dimethylcyclohexylamine added should be adjusted according to the specific application environment and performance requirements of the coating. Generally speaking, it is more appropriate to add between 0.1% and 1.0%.
Q2: What are the storage conditions for N,N-dimethylcyclohexylamine?
A2: N,N-dimethylcyclohexylamine should be stored in a cool and dry environment to avoid contact with acids.
Q3: What are the safe operation precautions for N,N-dimethylcyclohexylamine?
A3: N,N-dimethylcyclohexylamine has certain irritation. Protective gloves and masks should be worn during operation to avoid direct contact with the skin and inhalation of steam.
7.2 Product Parameters Table
| parameters | value |
|---|---|
| Appearance | Colorless transparent liquid |
| Purity | ≥99% |
| Moisture | ≤0.1% |
| Acne | ≤0.1 mg KOH/g |
| Flashpoint | 40°C |
| Packaging | 25kg/barrel |
7.3 Application Case Table
| Application Fields | Performance metrics | DMCHA not added | Add DMCHA (0.3%) |
|---|---|---|---|
| Building exterior wall coating | Weather resistance (hours) | 1000 | 1500 |
| Building exterior wall coating | Chemical resistance (grade) | 3 | 5 |
| Auto paint | Abrasion resistance (times) | 500 | 800 |
| Auto paint | Corrosion resistance (grade) | 4 | 6 |
| Ship Coating | Water resistance (hours) | 500 | 1000 |
| Ship Coating | Salt spray resistance (grade) | 3 | 5 |
Through the above content, we introduce in detail the mechanism of N,N-dimethylcyclohexylamine in improving the durability of polyurethane coatings, usage methods, product parameters and practical application cases. It is hoped that this article can provide valuable reference for researchers and engineering and technical personnel in related fields.
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