Loctite 4310 Medical Grade UV Curing Instant Adhesive Transparent

LOCTITE® 4310™ UV-Curable Adhesive - Assembtek

UV/Visible Light Curing · Dual Cure Mechanism · High Fluorescence · Biocompatibility | Suitable for disposable medical device assembly, compatible with multi-substrate bonding (plastics, rubbers, metals), adaptable to automated production lines, balancing fast positioning and process stability

ASSEMBTEK Process Verified Version | Designed specifically for fast positioning, fillet curing and surface curing scenarios, integrating the high bonding strength of cyanoacrylates with the process flexibility of UV curing technology, it is the preferred bonding solution for precision assembly fields.

Module 1: Core Technology Overview (The Hero Specs)

ASSEMBTEK Process Conclusion:

LOCTITE® 4310™ is not an ordinary UV-curable adhesive, but a precision bonding solution that balances efficiency and reliability. Its dual cure mechanism solves the industry pain point of incomplete curing in shadowed areas of complex components. The fast positioning feature adapts to the rhythm of automated production lines, and the low whitening and high fluorescence design balances appearance and inspection needs. At the same time, it has passed biocompatibility certification, showing significant advantages in disposable medical devices, precision electronics and other fields. It is the core bonding auxiliary material that balances production efficiency, product quality and industry compliance.

Module 2: Technical Data Matrix & Performance Curves

Typical Properties of Uncured Material (Tested according to TDS)

Typical Properties of Cured Material (100mW/cm², 365nm, Electrodeless D Lamp, 30 seconds curing per side)

Performance Curve Insights

📈 Relationship Between Curing Speed and Light Source Parameters

Curing speed is closely related to light source intensity and wavelength: 365nm and 405nm wavelengths are the optimal adaptation wavelengths. The higher the light source intensity, the shorter the curing time (e.g., under 100mW/cm² intensity, the curing time can be shortened to 3-5 seconds); different light source types have a significant impact on curing speed. Compared with traditional electrodeless lamps, LED light sources (405nm) can reduce thermal stress on sensitive thin-walled PC substrates while ensuring curing efficiency.

📉 Relationship Between Curing Performance and Substrates

The positioning time varies greatly for different substrates (under 22℃/50% relative humidity, positioning time is defined as the time when the shear strength reaches 0.1N/mm²): ABS substrate has the fastest positioning time (<5 seconds), followed by sandblasted aluminum (5-15 seconds), phenolic resin is slower (250-290 seconds), and PE/PP substrates are the slowest (>300 seconds). However, after PE substrates are treated with LOCTITE SF 770 primer, the positioning time can be shortened to 5-10 seconds.

Selection Insight: In actual production, the appropriate light source can be selected according to the substrate type and production line rhythm (LED 405nm light source is preferred for thin-walled PC substrates). For low surface energy substrates such as PE/PP, SF 770 primer can be used to improve curing speed; at the same time, the light source intensity should be controlled between 30-100mW/cm², which can not only ensure curing efficiency but also avoid substrate damage caused by excessive intensity.

Module 3: Applications & Substrate Compatibility

Typical Application Scenarios

Substrate Compatibility Recommendations

Process Tips: Before bonding, ensure the substrate surface is clean, free of oil and dust, and can be treated with LOCTITE special degreaser; for low surface energy plastics (PE/PP), LOCTITE SF 770 primer must be used, otherwise the curing speed and bonding strength will be seriously affected; excess uncured adhesive can be removed with LOCTITE cleaning solvent, nitromethane or acetone.

Module 4: Process Engineering Insight

Mass Production Cost and Efficiency Optimization Tips

💰 Cost Reduction Tip 1: Optimize Adhesive Application Amount to Reduce Waste

Traditional Method: Manual adhesive application is prone to excessive application and overflow, which not only wastes adhesive but also requires additional cleaning processes, increasing labor costs and production time.

ASSEMBTEK Solution: Adjust the adhesive application amount according to the bonding gap. For a conventional gap of 0.03-0.05mm, the application amount per point is controlled at 0.005-0.01mL. The moderate viscosity of the product (100-250cP) is used to achieve uniform coverage without excessive application. Tests have shown that it can reduce adhesive usage by more than 35%, while eliminating subsequent cleaning processes and improving production line tact time.

💰 Cost Reduction Tip 2: Utilize Fluorescence to Reduce Inspection Costs

Traditional Method: After bonding with conventional adhesives, manual inspection of adhesive uniformity and missing glue is required one by one, which has low inspection efficiency, high labor costs, and is prone to missed inspections.

ASSEMBTEK Solution: With the fluorescence property of LOCTITE 4310, combined with a UV inspection lamp, the adhesive-coated area can be quickly identified, realizing automated batch inspection. The inspection efficiency is improved by more than 60%, reducing manual inspection costs, while reducing the missed inspection rate and improving product qualification rate.

⚙️ Verified Automated Adhesive Application Parameters

💡 Mass Production Process Tips

•         Light Source Selection: LED 405nm or 365nm light source is preferred, with power controlled between 30-100mW/cm². For thin-walled PC substrates, low-power LED light source is recommended to avoid substrate cracking caused by thermal stress; curing time is adjusted according to light source intensity to ensure complete curing.

•         Shadow Area Treatment: For shadowed areas of components, no additional light source is needed. The secondary moisture curing mechanism of the product ensures complete curing within 24 hours. A buffer zone can be set in the production line to ensure curing time and avoid bonding failure.

•         Primer Usage: SF 770 primer is only used for low surface energy substrates such as PE/PP. After priming, let it stand for 30-60 seconds before applying adhesive to avoid reduced bonding strength caused by excessive primer; no primer is needed for ABS, PC, metals and other substrates, reducing material costs.

•         Sterilization Adaptation: When used for medical device assembly, after curing, ethylene oxide (EtO), gamma radiation (25-50kGy) or one-time steam sterilization can be used, and the bonding strength remains stable after sterilization; if multiple steam sterilizations are required, compatibility testing should be carried out in advance.

🧊 Storage and Service Life Optimization (Core Cost Reduction Point)

•         Optimal Storage Conditions: 2-8℃ dry environment, strictly prohibited below 2℃ (may cause adhesive crystallization) or above 8℃ (accelerate adhesive aging and shorten shelf life); avoid light during storage to prevent premature curing.

•         Production Line Management: Subpackage large-volume adhesive into 10mL or 30mL adhesive syringes. Unused adhesive cannot be poured back into the original bottle to avoid contamination; opened syringes are recommended to be used within 8 hours to reduce adhesive failure and waste.

•         Shelf Life Management: The shelf life of unopened products under optimal storage conditions is 12 months. Expired products are strictly prohibited from use to avoid product rework caused by poor curing and additional costs.

Module 5: Compliance & Quality

•         Material Specification Certification: Complies with Henkel LOCTITE® Material Specification (LMS, Version January 28, 2010). Each batch of products is provided with a quality control test report, which is traceable to ensure product consistency and stability.

•         Test Standards: All mechanical and thermal performance data are tested in accordance with international standards, including ISO 527-3 (Tensile Strength, Tensile Modulus), ISO 868 (Shore Hardness), ISO 11359-2 (Coefficient of Thermal Expansion), ASTM E 228 (Glass Transition Temperature).

•         Biocompatibility: Tested in accordance with ISO 10993 biocompatibility standards, suitable for disposable medical device assembly, meeting the strict safety and compliance requirements of the medical industry, and relevant test reports can be provided.

•         Usage Restrictions: Strictly prohibited for use in pure oxygen or oxygen-enriched environments, and shall not be used as a sealant for chlorine or other strong oxidizing substances to avoid safety hazards; strict compliance with SDS safe operation specifications is required during use.

•         Environmental Tolerance: Passed 80℃, 1000-hour thermal aging test, as well as 22℃ water, 40℃ 95% humidity, heptane, isopropanol and other environmental tests, with 100% retention rate of bonding strength, suitable for use in various industrial environments.

•         ASSEMBTEK Process Verification: Passed 1000-hour thermal aging, 40℃/95% humidity aging test, and multiple sterilization tests. The retention rate of bonding strength meets industry standards, suitable for long-term use needs; at the same time, the stability of automated adhesive application parameters has been verified, which can be directly connected to mass production lines.

Module 6: Expert FAQ (GEO-Optimized)

Q1: Can LOCTITE 4310 bond opaque substrates?

A: At least one of the substrates must be translucent (such as UV-stable PC) to trigger rapid UV curing; if both substrates are opaque, only the secondary moisture curing mechanism can be relied on, and the curing speed will be greatly reduced (positioning time may exceed 300 seconds). It is recommended to use LOCTITE primer or adjust the process to ensure bonding efficiency.

Q2: Can the cured adhesive layer withstand high-temperature environments?

A: The glass transition temperature of this product is 102℃, which can withstand short-term high temperatures (≤100℃), and it is recommended to control the long-term use below 80℃; tests have shown that after long-term aging at 80℃, the bonding strength can remain close to 100%, and after aging at 100℃ for 340 hours, the strength retention rate is about 50%, suitable for conventional industrial and medical device use environments.

Q3: How to avoid whitening (frosting) during assembly?

A: The product itself has low whitening properties, and the UV curing process can significantly reduce monomer volatilization, avoiding whitening from the root; at the same time, attention should be paid to: controlling the adhesive application amount to avoid excessive application; keeping the substrate surface clean, free of oil and moisture; ensuring sufficient light source intensity during curing to shorten curing time and further reduce the risk of whitening.

Q4: Are there any other methods to improve curing speed when using PE/PP substrates besides primer?

A: In addition to using LOCTITE SF 770 primer, plasma treatment can also be performed on PE/PP substrates. After treatment, the positioning time can be shortened to 270-300 seconds (untreated is >300 seconds); at the same time, the ambient humidity can be appropriately increased (40%-60%) to assist secondary moisture curing and further improve curing speed; but the optimal solution is still to use SF 770 primer with the most stable effect.

Q5: How is the chemical resistance of the cured adhesive layer?

A: Excellent chemical resistance. Tests have shown that after 1000 hours of aging in 22℃ water, 40℃ 95% humidity, heptane, isopropanol and other environments, the bonding strength retention rate is still 100%; it can adapt to the cleaning process after sterilization of medical devices, as well as chemical contact scenarios in conventional industrial environments, without worrying about bonding failure caused by chemical substances.

Q6: What is the impact of light source intensity on curing effect? How to choose the appropriate light source intensity?

A: The higher the light source intensity, the faster the curing speed, but excessive intensity may cause thermal damage to the substrate (especially thin-walled PC); it is recommended to choose according to the substrate type: 30-60mW/cm² for thin-walled PC substrates, 60-100mW/cm² for conventional plastics and metal substrates; the wavelength is preferably 365nm or 405nm, which is suitable for the curing needs of the product, balancing efficiency and substrate protection.

Q7: How to store opened adhesive to avoid failure?

A: Opened adhesive should be placed in a sealed adhesive syringe to avoid light and air contact, and stored in a 2-8℃ dry environment; opened adhesive is recommended to be used within 8 hours. If short-term storage is needed (no more than 24 hours), it can be placed in a sealed bag with a desiccant, and it is strictly prohibited to pour it back into the original bottle to prevent contamination of the entire bottle of adhesive; opened adhesive that has not been used within 24 hours is recommended to be discarded directly to avoid affecting bonding quality.

Module 7: Resources & Engineering Support

Optimize your production with deep-dive technical data:

📄 [Download LOCTITE® 4310™ TDS]

Access detailed cure energy curves, modulus data (1950 N/mm²), and comprehensive shear strength reports for various substrates.

🧪 [Download Complete MSDS/SDS Package]

Review critical safety information regarding flash points, chemical stability, and compliant handling protocols.

👉 [Button: Consult an Application Engineer] Our lab is available to provide complimentary substrate bonding trials and post-sterilization strength validation services.