In UV/EB curing systems, monofunctional acrylate 单体s are the building blocks that determine viscosity, adhesion, flexibility, and cure response. Among them, aromatic (benzene‑ring) 单体s form a distinct family defined by their conjugated ring structures – including phenyl, biphenyl, and benzyl groups.
These 单体s deliver high refractive index, high gloss, strong adhesion, and excellent dilution power, making them indispensable for indoor 涂料, printing inks, optical films, and general‑purpose UV adhesives.
However, they come with trade‑offs: poor weatherability, yellowing tendency, higher skin irritation, and limited compatibility with non‑polar polyolefins (PP, PE). Understanding these strengths and limitations is key to selecting the right 单体 for your formulation.
This guide covers six key aromatic 单体s: SINOMER® OPPEA, SINOMER® PHEA, SINOMER® BZA, SINOMER® BZMA, SINOMER® PBA, and SINOMER® NP-4EA, with performance data, application guidance, and selection criteria.
Across the family, benzene‑ring 单体s share these advantages:
| Attribute | Benefit |
|---|---|
| High refractive index | Increases gloss, depth, and color richness – essential for high‑gloss inks and overprint varnishes |
| Strong adhesion | Excellent wetting and anchoring on ABS, PC, PVC, PS, metals, glass, and epoxy surfaces |
| Excellent dilution power | Lowers viscosity of high‑molecular‑weight oligomers – suitable for inkjet, screen, and gravure printing |
| Good leveling | Reduces orange peel and cratering for smooth, defect‑free films |
| High rigidity & solvent resistance | Dense crosslinked films resist alcohol, solvents, and abrasion – superior to flexible heterocyclic 单体s |
| Limitation | Impact |
|---|---|
| Poor weatherability | Benzene rings absorb UV light – severe yellowing under outdoor exposure. Not suitable for exterior applications |
| Higher skin irritation | Most contain MEHQ; irritancy is higher than alicyclic or heterocyclic 单体s. Exercise caution in medical or food‑contact formulations |
| Brittleness | High loading can cause cracking, whitening on bending, or warping on thin films – blend with flexible 单体s to compensate |
| Poor adhesion to polyolefins | Weak wetting on PP, PE, and fluoroplastics – far inferior to ACMO, TBCHA, or THFA |
Biphenyl‑based premium 单体 with the highest refractive index among commercial monofunctional acrylates.
| Parameter | Value |
|---|---|
| Refractive Index | ~1.575 |
| Tg | ~32°C |
| Viscosity | 100 – 200 cps |
| Curing Shrinkage | < 5% |
Key Advantages:
Highest refractive index in its class – essential for AR/VR optics, OCA optical adhesives, and light‑guide 涂料
Balances hardness and toughness – low internal stress, minimal warping on thin films
Low odor and low skin irritation – suitable for food‑contact and UV nail gel applications
Good water, chemical, and heat resistance – outperforms single‑ring 单体s
Limitations:
Higher viscosity than PHEA or BA
Higher cost – premium positioning
Still susceptible to gradual yellowing under prolonged outdoor exposure
Pure film tends to soften at elevated temperatures (tackiness)
Primary Applications:
Optical films, AR/VR devices, high‑precision SLA 3D printing, photoresists, flexible electronic encapsulation, specialty adhesives.
The industry standard – most widely used aromatic monofunctional 单体 for general‑purpose UV systems.
| Parameter | Value |
|---|---|
| Refractive Index | ~1.516 |
| Tg | ~6°C |
| Viscosity | 5 – 15 cps |
| Curing Shrinkage | ~8% |
Key Advantages:
Best overall balance of adhesion, leveling, dilution, and hardness
Low viscosity – excellent processing characteristics
Highly cost‑effective – the go‑to “workhorse” 单体
Limitations:
Moderate weatherability – not suitable for long‑term outdoor use
Noticeable odor and skin irritation
Low Tg – limited heat resistance; prone to tackiness above 50°C
Primary Applications:
Indoor plastic 涂料, wood 涂料, screen/gravure UV inks, and general‑purpose UV adhesives.
The lowest‑viscosity aromatic 单体 – extreme dilution power and strong wetting.
| Parameter | Value |
|---|---|
| Refractive Index | ~1.514 |
| Tg | ~3°C |
| Viscosity | 2 – 5 cps |
| Curing Shrinkage | ~9% |
Key Advantages:
Extremely low viscosity – excellent reactive diluent
Superb wetting – improves substrate penetration
Enhances optical clarity of cured films
Limitations:
Higher volatility and stronger odor
More brittle film compared to other aromatic 单体s
Poorer yellowing resistance
Primary Applications:
UV inkjet inks, high‑solid gloss 涂料, and auxiliary viscosity‑reduction 单体.
The methacrylate analogue of BZA – higher Tg, better heat resistance.
| Parameter | Value |
|---|---|
| Refractive Index | ~1.513 |
| Tg | ~54°C |
| Viscosity | 8 – 15 cps |
Key Advantages:
Higher Tg than BZA – improves heat and block resistance
Better scratch resistance and hardness
Slightly lower odor and volatility than acrylate version
Primary Applications:
Heat‑resistant plastic 涂料, appliance UV 涂料, and high‑temperature electronic inks.
Biphenyl‑based specialty 单体 for high‑end optical and chemically resistant systems.
| Parameter | Value |
|---|---|
| Refractive Index | ~1.570 |
| Tg | ~33°C |
| Viscosity | 40 – 80 cps |
Key Advantages:
High refractive index – optical‑grade clarity
Strong chemical resistance – suitable for aggressive solvent environments
Low shrinkage and good toughness – better than BZA
Primary Applications:
Premium optical inks, transparent UV adhesives, lens 涂料, and high‑end encapsulation.
Extreme wetting 单体 for difficult substrates – domestic use only.
| Parameter | Value |
|---|---|
| Refractive Index | ~1.498 |
| Tg | ~ –12°C |
| Viscosity | 30 – 60 cps |
Key Advantages:
Excellent wetting on difficult plastics and leather surfaces
Strong adhesion to low‑energy substrates
Cost‑effective for industrial applications
Critical Limitation:
Contains nonylphenol ethoxylates – subject to EU REACH restrictions (Annex XVII). Prohibited for export to the EU. Only suitable for domestic industrial formulations in markets without NP regulations.
Primary Applications (Domestic Only):
Leather UV 涂料, low‑end plastic inks, industrial wood 涂料.
| Scenario | Recommended 单体s |
|---|---|
| High‑gloss 涂料 & inks | OPPEA, PHEA, BZA |
| Adhesion to polar plastics (ABS, PC, PVC) | PHEA, OPPEA, PBA |
| Low‑viscosity inkjet formulations | BZA |
| Heat‑resistant 涂料 | BZMA |
| Optical/AR/VR applications | OPPEA, PBA |
| Cost‑effective general‑purpose UV systems | PHEA |
| Food‑contact or low‑irritation formulations | OPPEA |
| Scenario | Why | Alternative |
|---|---|---|
| Outdoor / UV‑exposed applications | Severe yellowing | Alicyclic or heterocyclic 单体s (CHA, THFA, ACMO) |
| Adhesion to PP / PE | Poor wetting | ACMO, TBCHA, THFA |
| Flexibility / low‑shrinkage | Brittle films | Flexible heterocyclic 单体s |
| EU REACH compliance | NP series contains restricted substances | PHEA, OPPEA, or non‑NP alternatives |
| Medical / food‑contact with MEHQ restrictions | Skin irritation and regulatory concerns | MEHQ‑free alicyclic or heterocyclic 单体s |
| Product | Key Feature | Best‑For Applications |
|---|---|---|
| SINOMER® OPPEA | Highest RI (1.575), low irritation | Optical 涂料, AR/VR, 3D printing, photoresists |
| SINOMER® PHEA | Best cost‑performance balance | General indoor 涂料, inks, adhesives |
| SINOMER® BZA | Lowest viscosity, extreme dilution | UV inkjet, high‑solid gloss 涂料 |
| SINOMER® BZMA | Highest Tg, heat resistance | Heat‑resistant plastic 涂料, appliance 涂料 |
| SINOMER® PBA | High RI, chemical resistance | Premium optical inks, lens 涂料, transparent adhesives |
| SINOMER® NP-4EA | Extreme wetting (NP‑based) | Domestic leather and industrial 涂料 only – not for EU |
Q: What is the main difference between aromatic and alicyclic 单体s?
A: Aromatic 单体s (benzene‑ring) offer higher refractive index, gloss, and adhesion but yellow under UV exposure. Alicyclic 单体s offer superior weatherability, lower yellowing, and better adhesion to polyolefins.
Q: Which aromatic 单体 has the highest refractive index?
A: SINOMER® OPPEA has the highest refractive index (~1.575) among commercial monofunctional acrylates.
Q: Can I use aromatic 单体s for outdoor 涂料?
A: Generally no. They yellow rapidly under UV exposure. For outdoor applications, use alicyclic or heterocyclic 单体s.
Q: Is SINOMER® BZA suitable for inkjet inks?
A: Yes. Its extremely low viscosity and excellent dilution power make it ideal for low‑viscosity UV inkjet formulations.
Q: Can I replace PHEA with BZA to reduce viscosity?
A: Yes, but be aware BZA gives more brittle films and higher odor. Test adhesion and flexibility before full replacement.
Q: What is the difference between BZA and BZMA?
A: BZMA is the methacrylate version – it offers higher Tg (54°C vs 3°C), better heat resistance, and slightly lower volatility.
Q: Is NP-4EA suitable for EU export?
A: No. NP‑4EA contains nonylphenol ethoxylates, which are restricted under REACH. Use PHEA or OPPEA for EU‑bound formulations.
Q: Can I use OPPEA for food‑contact applications?
A: OPPEA offers lower odor and skin irritation, but food‑contact approval depends on final formulation and regulatory compliance. Please contact our technical team for specific guidance.
Q: How do I formulate flexible yet glossy 涂料?
A: Blend aromatic 单体s (for gloss) with flexible heterocyclic or aliphatic 单体s to balance hardness and flexibility.
中固化学集团
No. 61, South Industrial Road, Jinan Area of Shandong Pilot Free Trade Zone, China
Email: Info@sinocurechem.com | Tel: +86 15668330235
Website: www.sinocurechem.com
For samples, technical data sheets, or custom formulation support, please contact our technical team.
This document is for informational purposes only. Users should conduct their own testing to determine suitability for their specific applications. SINOMER® is a registered trademark of 中固化学集团.
