AM-318 is a monofunctional acryloylmorpholine monomer, chemically known as N-acryloylmorpholine (ACMO, CAS: 5117-12-4). In UV-curable systems, AM-318 is commonly used as a reactive diluent or performance-modifying monomer. It is found in formulations for UV inkjet inks, label printing inks, plastic coatings, electronic adhesives, and other light-curable applications.
Key Parameters of AM-318
| Property | Typical Value |
|---|---|
| Functionality | 1 |
| Viscosity (25°C) | 12 mPa·s |
| Glass transition temperature (Tg) | 120°C |
| Surface tension | 33 dynes/cm |
| Acid value | ≤2 mgKOH/g |
| Water solubility | Miscible with water |
AM-318 has a low viscosity and good diluting capability among monofunctional monomers, making it useful for reducing the overall viscosity of a formulation. Its relatively high Tg can help increase the hardness and heat resistance of the cured film. AM-318 is also water-soluble and miscible with water and many organic solvents, making it suitable for waterborne UV systems or processes that require water washing.
Performance Characteristics of AM-318
Low viscosity and dilution efficiency
At 25°C, AM-318 has a viscosity of approximately 12 mPa·s. It can effectively reduce the viscosity of UV resin systems and improve flow during spraying, inkjet printing, and other application processes.
High Tg and hardness contribution
The homopolymer of AM-318 has a Tg of about 120°C. After curing, it can contribute to higher surface hardness and heat resistance, making it suitable for coatings that require wear resistance or thermal stability.
Fast curing
Among similar monofunctional monomers, AM-318 shows good reactivity. It is suitable for LED low-energy curing systems and can help shorten curing time.
Water solubility
AM-318 is fully miscible with water. This allows it to be used in waterborne UV systems and can also facilitate water washing in certain processes.
Adhesion and low shrinkage
AM-318 wets plastic substrates such as PC, PMMA, and PET relatively well. This can help improve coating adhesion and reduce stress caused by curing shrinkage.
Low odor and low skin irritation
Compared with some traditional acrylate monomers, AM-318 has lower odor and lower skin irritation, which can improve the working environment.
Non-corrosive to metal substrates
AM-318 does not contain acrylic acid in its molecular structure and is non-corrosive to metal substrates. This makes it suitable for electronic materials and other applications where substrate compatibility is important.
Specific Applications of AM-318
UV Inkjet Inks
The low viscosity of AM-318 helps ink flow smoothly through high-frequency printheads. Its surface tension can improve wetting on substrates such as paper, PET, and PP, reducing misting and bleeding. Its relatively fast curing speed helps shorten drying time in the printing process.
Label Printing UV Inks
Label printing often requires good surface abrasion resistance and dimensional stability. AM-318 has a relatively high Tg, which can contribute to a harder cured ink layer and improve scratch resistance on label surfaces. The monomer also has good compatibility with common UV ink solvents such as ethanol and propylene glycol methyl ether, as well as with polyester and acrylic resins.
Plastic Substrate UV Coatings
For plastic surface treatment, adhesion and hardness are common technical challenges. The low shrinkage of AM-318 helps reduce stress between the coating and substrate during curing, lowering the risk of cracking or peeling. Its polar structure wets PC, PMMA, and similar plastics relatively well, which can improve coating uniformity.
Electronic Adhesives and UV Adhesives
The rigid structure of AM-318 can provide UV adhesives with fast initial strength and higher cured adhesive rigidity. Its low shrinkage helps reduce the risk of performance degradation in precision components caused by adhesive deformation. Since the monomer does not contain acrylic acid, it is non-corrosive to metal substrates and suitable for electronic materials where substrate compatibility is required.
Waterborne UV Systems
Because of its water solubility, AM-318 can be used to formulate waterborne UV coatings and inks. This can reduce the amount of organic solvent used and is suitable for formulations where VOC emissions are a concern.
3D Printing and Functional Materials
The low viscosity and water solubility of AM-318 make it useful in some DLP/SLA 3D printing resins as a reactive diluent or as a component of water-soluble support materials. It can also be used to prepare functional materials such as ionic conductive elastomers and hydrogels.
Formulation Recommendations for AM-318
Dosage
In UV coatings or adhesive formulations, the recommended addition level of AM-318 is typically 5%–15% to improve adhesion and adjust curing speed. If used as the main reactive diluent, the proportion can be increased, but excessive amounts may increase coating brittleness. It is recommended to balance with flexible oligomers or lower-functionality monomers.
Curing light source
AM-318 is compatible with 365 nm UV light sources, including mercury lamps and LED sources. A light intensity of no less than 80 mW/cm² is recommended to ensure sufficient curing. Actual curing conditions should be adjusted through small-scale trials based on the formulation and equipment.
Co-formulation suggestions
AM-318 can be used with multifunctional oligomers, polyurethane acrylates, epoxy acrylates, and other resins to balance hardness, flexibility, and curing speed. For applications requiring high solvent resistance or high crosslink density, it is recommended to combine AM-318 with multifunctional monomers or oligomers.
Limitations
AM-318 is a monofunctional monomer and has limited crosslink density. If a formulation requires high chemical resistance, solvent resistance, or high strength, multifunctional monomers and oligomers should be used to reinforce the cured network.
FAQ About AM-318
What is AM-318?
AM-318 is an acryloylmorpholine monomer, chemically known as N-acryloylmorpholine (ACMO). It is a monofunctional UV-curable monomer.
Is AM-318 the same as ACMO?
AM-318 corresponds to the chemical substance ACMO, or N-acryloylmorpholine.
What fields is AM-318 mainly used in?
AM-318 can be used in UV inkjet inks, label printing inks, plastic substrate coatings, electronic adhesives, waterborne UV systems, and some 3D printing materials.
What is the recommended dosage of AM-318?
A common addition level is 5%–15%. The exact ratio should be determined through small-scale trials based on formulation targets, substrate, and curing equipment.
What curing conditions does AM-318 require?
It is typically compatible with 365 nm UV light sources. A light intensity of no less than 80 mW/cm² is recommended. Actual conditions should be adjusted according to the formulation and equipment.
Summary
The core value of AM-318 lies in its balance of low viscosity, relatively high Tg, fast curing, and water solubility. For formulations that need to reduce system viscosity while maintaining cured film hardness, AM-318 provides a measurable option. In practical use, it is recommended to conduct small-scale trials based on the specific substrate, curing equipment, and performance targets to determine the optimal addition level.