UV Adhesives

UV Adhesives for Bonding Flexible Tubing Sets and Fluid Connectors

A fluid-transfer set spends its working life being bent, coiled, tugged, and pressurized. The bonds where flexible tubing meets a rigid connector are where that abuse concentrates, so the adhesive has to stretch with the tubing instead of forming a hard, brittle collar that cracks. The flex-fatigue problem at a tube joint When a soft PVC or thermoplastic elastomer tube is bonded into a rigid polycarbonate or ABS fitting, there is an abrupt change in stiffness right at the edge of the bond. Every flex cycle puts a stress concentration there. A rigid, high-modulus adhesive makes it worse by extending the stiff zone; the tube then fatigues and splits just past the connector. An adhesive with high elongation and a lower cured modulus spreads the bending strain over a longer length and moves with the tube. Incure's Cyro-Weld™ 5000-series includes grades formulated for this, with high elongation and good adhesion to flexible substrates, such as 5013VT and 5004F. They cure in seconds under UV or visible light, are formulated to meet ISO 10993-5, and are validated for EtO and Gamma sterilization. The very thixotropic VT grade holds its shape in the annular gap between tube and fitting rather than running out before cure. Where these adhesives are used Bonding flexible tubing into luer and barbed connectors Assembling drip chambers, spikes, and Y-sites in fluid-transfer sets Joining flexible and rigid sections of drainage and irrigation sets Bonding strain-relief boots and grommets to cable and tube exits Sealing flexible bladder and reservoir components to rigid ports All external, single-use fluid-handling components. Making the joint The tube-to-fitting joint is usually an annular gap a few tenths of a millimeter wide. The adhesive is applied to the fitting bore or the tube end, the parts are assembled to a stop, and the joint is cured through the translucent tube or fitting wall. Because at least one part is often clear, the cure light can reach the bond line directly; where a fitting is opaque, a visible-light-responsive grade or a secondary cure mechanism completes the bond. Incure's guidance on matching a spot-lamp light guide to reach and working distance and what a light guide does in a spot-lamp system covers curing these small, curved joints on a line. Surface preparation for flexible substrates Flexible PVC and elastomers carry mobile plasticizers and process oils that migrate to the surface. Wiping the tube end with a clean solvent immediately before bonding removes that weak boundary layer. Some elastomers also benefit from a brief plasma treatment. Incure's discussion of matching a plastic-bonding grade to the substrate and mechanical demand covers the trade-offs for soft substrates. Why elongation and CTE both matter A flexible-to-rigid joint is stressed two ways: mechanically, every time the set is handled, and thermally, whenever it warms or cools, because the soft tube and the rigid fitting expand at very different rates. Incure's explanation of how CTE mismatch causes bond failure covers the thermal side. A high-elongation adhesive absorbs both kinds of movement; a rigid…

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August 10, 2024
UV Adhesives

UV-Curable Protective Coatings for Medical Device Electronics

A wearable monitor or a handheld diagnostic reader packs a small circuit board into a housing that will meet sweat, cleaning wipes, and condensation for its whole service life. A thin protective coating over that board is what keeps humidity and ionic contamination from bridging traces and killing the device early. The job of a protective coating on a device board The electronics inside an external medical device are not sealed hermetically; they are protected by the enclosure and by a conformal coating on the board itself. That coating has to form a continuous dielectric barrier, resist the moisture that gets past the enclosure seals, tolerate repeated wipe-down with disinfectant, and survive the sterilization method used on the finished product, all without adding enough thickness or stiffness to crack at a component corner. Incure's Cyro-Weld™ 5000-series includes low-viscosity UV-curable grades suited to this role, such as 5002F and 5004F. They are formulated to meet ISO 10993-5 and are validated for EtO and Gamma sterilization, so a coating used on an external device that contacts skin or is handled by a patient carries the same documented testing as the structural adhesives elsewhere in the build. Why UV cure A UV-curable coating is 100% solids and cures in seconds under a lamp. For a device line that means no solvent handling, no drying oven, predictable film thickness, and a board that is ready to move to final assembly immediately. The alternative chemistries, solvent acrylics and moisture-cure silicones, either need long dry times or leave a soft film that picks up contamination. Fluorescing for coverage verification The F in these grades is a fluorescent tracer. Under a UV inspection lamp the coated area glows and any skip, thin spot, or run shows up immediately. On a small, densely populated device board where a bare pad the size of a grain of rice can cause a field failure, that inspection capability is not optional. It also feeds a pass/fail signal to an automated optical inspection station on a high-volume line. Handling shadowed areas A UV coating cures where light reaches it, and a populated board has shadow under every tall component and connector. Incure's UV coatings pair the primary light cure with a secondary moisture-cure mechanism: shaded resin slowly crosslinks by reacting with ambient humidity over the following hours, so the film reaches full properties across the whole board. Getting adequate primary dose depends on the lamp; see Incure's guidance on matching a UV LED flood lamp to curing area and intensity and, because lamp output falls with use, what causes UV light guide degradation over time. Application steps Clean and dry the board; flux and ionic residue trapped under the coating will corrode regardless of coating quality Mask connectors, contacts, antennas, and any test points Apply a uniform film in the specified thickness band by selective spray or dip UV-cure the exposed film, then hold the assembly in shop humidity so shaded resin completes its moisture cure Verify coverage under a UV lamp…

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August 10, 2024
UV Adhesives

Medical-Grade UV Adhesives for Disposable Device Assembly

Assembling a disposable fluid-transfer set or a handheld diagnostic consumable means bonding several dissimilar plastics in seconds, with a joint that has to survive shipping, shelf life, and a sterilization cycle. UV-curable medical-grade adhesives are built for exactly that combination of speed and documented safety. What "medical-grade" actually means The label is not marketing. For a device-assembly adhesive it means the cured material has been tested against recognized standards for patient-contacting and fluid-contacting components. Incure's Cyro-Weld™ 5000-series UV adhesives are formulated to meet ISO 10993-5 for cytotoxicity and are validated for EtO and Gamma sterilization, so a manufacturer can cite that testing in a device history file rather than commissioning it from scratch. Just as important is lot-to-lot consistency. A medical-grade adhesive is made to a locked formulation and specification with full traceability, because a device maker has to be able to show that the material bonding this month's production is identical to the material that passed qualification. Why UV cure fits disposable assembly Disposable devices are high-volume and cost-sensitive. A UV-curable adhesive cures on demand in seconds when exposed to UV or visible light, which means: Parts can be positioned and inspected before the cure is triggered, then fixed instantly There is no mixing, no pot life, and no oven queue The adhesive is 100% solids, so nothing evaporates and joint dimensions stay predictable Line rate is set by handling speed, not by cure chemistry The 5000-series spans low-viscosity grades that wick into tight-clearance connector joints, such as 5013 and 5017, and thixotropic variants like 5013T and 5013VT that stay put on a vertical bond line or bridge a visible gap. Fluorescing grades for inspection Grades carrying an F suffix, such as 5002F, 5004F, and 5013F, contain a fluorescent tracer. Under a UV inspection lamp the cured adhesive glows, so an operator or a machine-vision station can confirm that adhesive is present, that it is in the right place, and that it has not wicked into a lumen or onto a sealing face where it does not belong. On a clear-on-clear plastic joint this is often the only practical verification method. Substrate matters Medical device housings and consumables are molded from polycarbonate, ABS, PETG, acrylic, cyclic olefin copolymer, and thermoplastic elastomers. These vary widely in surface energy and in how well an adhesive anchors to them. Low-surface-energy plastics may need plasma or corona treatment immediately before bonding. Incure's discussion of matching a plastic-bonding adhesive grade to the substrate and mechanical demand covers the selection logic, and its overview of how CTE mismatch causes bond failure explains why a joint between two different plastics can fail during temperature cycling or sterilization even when the initial bond looked sound. Getting a complete cure UV adhesive only cures where light reaches it. In a connector joint, resin can sit in shadow behind an opaque hub. Several 5000-series grades include a secondary cure mechanism so shadowed adhesive still reaches full properties. Delivering adequate primary UV dose depends on the lamp; see Incure's guidance…

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August 9, 2024
UV Adhesives

Cyro-Weld™ Adhesives for Disposable and External Device Components

Assembling disposable and external medical device components, fluid connectors, luer fittings, housings, tubing sets, wearable sensor enclosures, and diagnostic cartridges, calls for adhesives that bond dissimilar plastics fast, hold up to sterilization, and are formulated to meet biocompatibility screening. Incure's Cyro-Weld™ line covers this work with two chemistry families: light-cure adhesives and medical-grade cyanoacrylates. Two Chemistries for Component Bonding Cyro-Weld™ 5000-series are UV and visible-light curable adhesives. They stay liquid until exposed to the right wavelength, then fix in seconds, which suits automated dispensing and high-volume assembly. Grades such as 5002F, 5004F, 5005F, 5013F, and 5017F carry a fluorescing tracer so coverage can be verified under inspection light. The series is formulated to meet ISO 10993-5 cytotoxicity screening, and individual grades are validated for EtO and Gamma sterilization exposure. Cyro-Weld™ CM-series are medical-grade cyanoacrylates that cure with ambient moisture and need no light path, making them the choice for opaque assemblies and shadowed joints. The series spans a wide viscosity range, from low-viscosity wicking grades like CM-2 and CM-3 that penetrate tight press-fit joints, through general-purpose grades such as CM-50 and CM-105, to gel and toughened grades like CM-2500 and CM-4000 for gap filling and vibration resistance. CM-series grades are formulated to meet ISO 10993-5. Matching a Grade to the Joint Viscosity and gap: Wicking grades for close-fit connectors and hub-to-tube joints; medium grades for general bonding; gel grades where the gap is uneven or vertical. Cure access: Light-cure 5000-series where a UV path exists and cycle time is tight; moisture-cure CM-series for opaque housings and blind joints. Substrate: Both families bond common device plastics such as polycarbonate, ABS, acrylic, and many polyolefins after appropriate surface preparation. The plastic bonder grade-selection guide covers substrate matching in detail. Inspection: Fluorescing grades where automated or manual coverage verification is part of the line. Sterilization and Compliance Cyro-Weld™ grades are formulated to meet ISO 10993-5 cytotoxicity requirements, and specific grades are validated for ethylene oxide and Gamma irradiation sterilization without loss of bond integrity. Incure supplies materials, not finished devices; the device manufacturer remains responsible for full biological evaluation and validation of the finished assembly. These adhesives are intended for external and disposable device components, not for implantation or long-term tissue contact. For grade recommendations against your substrates and sterilization method, Email Us. Designing the Bond Cyanoacrylate and light-cure acrylate bonds both perform well in thin, well-fitted joints loaded in shear rather than peel or cleavage. Where two plastics with different expansion rates are joined, a coefficient of thermal expansion mismatch drives stress at the bond line during sterilization thermal excursions and shipping; a slightly flexible toughened grade absorbs that movement better than a rigid one. Clear assemblies where the bond line is visible benefit from the guidance in choosing an adhesive for transparent bonding. Process Notes Surface preparation: Clean and, for low-energy plastics, plasma or primer treat. Contamination is a leading cause of weak bonds. Dispensing: Both families dispense through fine needles for precise placement; the 5000-series suits inline automated dosing. Light…

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August 9, 2024