AM-3113 is the product code for 3,3,5-trimethylcyclohexyl acrylate, also commonly referred to as TMCHA. It is a monofunctional cycloaliphatic acrylate monomer with CAS number 86178-38-3, molecular formula C₁₂H₂₀O₂ and molecular weight 196.29. In UV/EB curing systems, AM-3113 is typically used as a reactive diluent or functional monomer. Its performance sits between high-hardness monomers such as IBOA and highly flexible monomers such as THFA, making it suitable for formulations that need a balance of adhesion, low shrinkage and weatherability.
Chemical Structure and Performance Positioning
The AM-3113 molecule consists of a cyclohexane ring linked to an acrylate group through an ester bond. Three methyl groups are substituted at the 3, 3, and 5 positions of the cyclohexane ring. The ring structure provides rigidity and abrasion resistance, while the methyl side chains reduce close packing between molecules, preventing the cured film from becoming excessively hard and brittle. This "rigid-flexible balance" is a key characteristic that distinguishes AM-3113 from similar cycloaliphatic monomers such as IBOA and TBCHA.
Key Performance Indicators
| Property | Typical Value |
|---|---|
| Functionality | 1 |
| Homopolymer Tg | Approx. 43°C |
| Viscosity at 25°C | 2–8 mPa·s |
| Surface tension (20°C) | 27.1 dyn/cm |
| Volumetric shrinkage | <5% |
| Acid value | ≤ 0.5 mg KOH/g |
| Refractive index (25°C) | 1.453 |
| Specific gravity (20/20°C) | 0.93 |
The data above is compiled from technical documents provided by multiple suppliers. It should be noted that some sources list the Tg of AM-3113 as 162°C, while most technical documents and measured data point to approximately 43°C. This discrepancy may be related to test methods or isomer ratios. For specific projects, the supplier's COA should be consulted.
The most notable performance feature of AM-3113 is its very low curing shrinkage. With volumetric shrinkage controlled below 5%, it is significantly lower than many common monofunctional monomers such as IBOA and THFA. In thin films or thin coatings, low shrinkage means low internal stress, which helps reduce warping, delamination and cracking. At the same time, its viscosity at 25°C is only 2–8 mPa·s, giving it strong dilution capability. This can effectively reduce the viscosity of a formulation and decrease the amount of non-reactive solvent required.
Comparison with Similar Monomers
| Property | IBOA | THFA | TBCHA | AM-3113 |
|---|---|---|---|---|
| Tg (°C) | 94 | -12 | 72 | 43 |
| Viscosity (mPa·s) | 8–12 | 4–8 | 12 | 2–8 |
| Flexibility | Low | High | Medium | High |
| Adhesion | Medium | Medium | Good | Good |
| Curing shrinkage | High | Medium | Low | Very low |
| Odor | Medium | Medium | Low | Low |
Flexibility, adhesion and odor are relative ratings based on supplier technical data.
Compared with IBOA, AM-3113 has a lower Tg (43°C vs 94°C), so the cured film is less likely to become hard and brittle. Its odor and skin irritation are also noticeably lower. Compared with THFA, AM-3113 offers better hydrolysis resistance and weatherability, with a higher Tg, making it suitable for coatings that require some hardness. Compared with TBCHA, AM-3113 provides better adhesion, toughness and weatherability. TBCHA has a higher Tg (72°C), which still has value in applications requiring higher hardness, but AM-3113 has advantages in low shrinkage and adhesion.
Main Applications
UV Coatings
In UV coatings, AM-3113 is used as an additive-type monomer. Its main functions are to improve adhesion, reduce volumetric shrinkage and enhance leveling. With a surface tension of only 27.1 dyn/cm, it wets and bonds well to substrates such as PC, ABS, PET, PMMA, glass and metal. The cycloaliphatic structure contains no benzene ring, so weatherability and resistance to thermal yellowing are better than those of aromatic monomers. This makes it suitable for outdoor coatings and long-term exposure applications. Its hydrolysis resistance is also better than that of many linear alkyl acrylates, helping to maintain performance in humid environments.
UV Laminating Adhesives and Adhesives
Laminating adhesives are an application where AM-3113 can clearly demonstrate its differentiated advantages. PET laminating films are often only a few tens of microns thick. The curing shrinkage of ordinary monomers can generate significant internal stress, causing the finished film surface to wave, edges to lift, or layers to separate after storage. AM-3113 has a volumetric shrinkage of less than 5%, so the volume change before and after crosslinking is small. This can noticeably improve film flatness and long-term storage stability.
In UV-curable adhesives such as speaker center adhesives, AM-3113 can be used as a primary reactive diluent. It reduces system viscosity while providing good hardness and bonding performance. Its low odor and low skin irritation also make it more user-friendly in manual handling scenarios.
UV Inkjet and Inks
The low viscosity and strong dilution capability of AM-3113 make it suitable for high-speed inkjet formulations. It can reduce the proportion of non-reactive solvent in the formula. Its pigment wetting properties are relatively good, helping to improve ink leveling and color performance. The cured film has good toughness and chemical resistance, making it suitable for printing on plastic films such as PET, PA, PC and PS, as well as on copper-clad laminates, metal coatings, glass and other surfaces.
UV 3D Printing
In stereolithography (SLA) and digital light processing (DLP) 3D printing, AM-3113 can participate in fast curing. Its low shrinkage helps improve the dimensional accuracy of printed parts and reduce deformation during post-curing.
Compatibility and Formulation Recommendations
AM-3113 has good compatibility with various monofunctional and multifunctional acrylate monomers. It is miscible with common organic solvents such as acetone and ethyl acetate. It is also fully miscible with acrylic, polyester, epoxy and polyurethane acrylate resins.
A few points should be noted in formulation. As a monofunctional monomer, AM-3113 cannot usually be used alone in large amounts. It is typically combined with difunctional or multifunctional monomers to maintain sufficient crosslink density. Excessive use may reduce crosslink density and affect alcohol resistance and chemical resistance. In waterborne UV systems, AM-3113 can be used as a reactive diluent to reduce application viscosity, decrease co-solvent demand, and improve the toughness and adhesion of the dry film to plastic substrates.