Product Overview
LOCTITE AA 3311 is a highly versatile, one-part acrylic adhesive formulated for precision bonding where stress-sensitive plastics (such as polycarbonate), metals, glass or ceramics are involved. It cures rapidly when exposed to UV/visible light, typically achieving fixture in around 12 seconds, and reaches a cure depth greater than 13 mm under suitable irradiation conditions.
Because of its low viscosity (approximately 200–400 mPa·s) and excellent compatibility with close-fitting assemblies (<0.25 mm gap), it is particularly well-suited to medical-device manufacturing, electronics, transparent plastic assemblies and other applications where simplicity and precision matter.
Key Features & Benefits
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Low viscosity, one-component system — no mixing, simplifying application and reducing waste.
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Rapid fixturing (~12 s) — enables high-throughput assembly and minimal dwell time.
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Excellent for stress-sensitive plastics — specifically formulated to bond materials like polycarbonate without inducing stress-cracking under typical molded stress.
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Transparent cured bond — ideal for visible assemblies and applications where aesthetic clarity is important.
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Biocompatible (ISO-10993 tested) — suitable for medical device assemblies where regulatory compliance is required.
Application
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Surface Preparation: Ensure that bonding surfaces are clean, dry and free of grease, dust or coatings. For plastics, remove mold release agents or oils as required.
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Application: Apply a small amount of LOCTITE AA 3311 to one of the mating surfaces. Because of its low viscosity, ensure correct quantity and gap control (~0.25 mm or less).
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Assembly & Positioning: Bring the parts together promptly. Since cure is triggered by light, ensure that the adhesive layer and bond line are exposed appropriately.
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Curing: Expose the bonded assembly to a suitable UV/visible light source per the irradiation specifications in the TDS (fixture in approx. 12 s under ideal conditions).
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Handling & Full Cure: After initial fixturing, allow sufficient time (as per manufacturer’s guidance) before placing into full service.
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Disassembly / Repair: This adhesive is designed for permanent bonding. If removal is required, review the TDS for appropriate removal procedures (usually mechanical or via specialized methods).
Tips:
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Use appropriate light intensity and exposure duration to ensure full cure through the bond thickness.
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For opaque substrates or thick bondlines, ensure light penetration is sufficient or consider dual-cure alternatives.
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Ensure proper fixture, as repositioning after light exposure may be difficult.
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Monitor ambient conditions (temperature, humidity, substrate cleanliness) for optimum performance.
FAQs
Q1: Can LOCTITE AA 3311 bond polyolefin plastics (e.g., PP, PE) without primer?
A1: This product is optimized for stress-sensitive plastics such as polycarbonate and many engineering plastics. For polyolefins (PP/PE) a primer or alternative adhesive is typically required; please consult the TDS for compatibility.
Q2: What is the typical fixturing time?
A2: Under defined UV/visible irradiation, the fixture time can be as low as ~12 seconds. Actual time depends on light intensity, substrate transmissivity and gap size.
Q3: Is this adhesive suitable for medical device manufacturing?
A3: Yes — LOCTITE AA 3311 has been tested according to ISO-10993 biocompatibility protocols, making it suitable for many medical device assembly applications.
Q4: What gap size should I target for best performance?
A4: The product is designed for small bond gaps (less than ~0.25 mm) to ensure optimal adhesive penetration and rapid cure.
Q5: What if the bond area is opaque or light cannot reach the adhesive directly?
A5: If UV/visible light cannot effectively reach the bondline (due to opaque substrates or large bond thickness), cure may be incomplete or slower. In such cases, consider adhesives with additional cure mechanisms (e.g., dual-cure) or ensure light exposure from the edge.
