Needle Bonding
Hoenle medical grade adhesives for needle bonding help to produce products of the highest quality in an optimized assembly process. A wide array of adhesive selections is available to ideally match the substrate of the hub and provide the quickest fill for the specified bond gap. Low viscosity adhesives are best suited for tight gaps and for filling annular channels molded into the inside diameter of the hub body. Higher viscosity adhesives provide a more controlled flow to help prevent adhesive occlusion the base of the inserted needle before it can be cured.
Already the hub material used affects the choice of adhesive, since not all adhesives adhere well to all plastics. Many adhesives are UV-curing, which requires the use of transparent and UV-permeable materials. For materials that block UV light, such as polycarbonates, long-wave LED curing is recommended. All needle bonding adhesives listed in the table below can be LED-cured.
Needle Bonding in High volume production
Needle bonding and syringe assembly represent some of the highest volume production processes in the medical device disposables market. The primary application for adhesives in needle bonding involves glueing (or cementing) a stainless-steel needle (cannula) into a hub that is typically molded from polypropylene, styrene, ABS, or polycarbonate. The needle/hub assembly is then affixed to the syringe body. The syringes can be simple push-plunger type, or they can be more intricately designed safety syringes for lower risk of accidental “sticks”. The needles may also be bonded directly into a single-use glass syringe. In all cases, the bonded needles must maintain both high pullout and tortional strength after their assembly.
Needles are bonded with fluorescent adhesives to facilitate quality control of the bonds
The video shows how a needle bonding process can be implemented with UV adhesives and UV curing systems from Hoenle and automated dispensing equipment from bdtronic
Read more in our case study on needle bonding
High quality adhesives for high quality needle bonds
All Hoenle adhesives recommended for needle bonding are solvent-free and certified USP Class IV and/or ISO 10993 biocompatibility. They are highly compatible with common sterilization methods including EtO, gamma, and Electron-Beam. E-Beam sterilization has shown to improve increase the adhesion of some adhesives from the Hoenle medical grade series. Laboratory testing has shown that Hoenle adhesives maintain their high bond strength after several cycles of sterilization.
All adhesives are also available in fluorescent versions, which allows a fast and efficient quality control during production. Many of our medical grade adhesives are also available in different viscosities to optimize the dispensing process.
Selection of our needle bonding adhesives
The table below lists a selection of needle bonding adhesives from Hoenle. Further products and custom solutions for needle assembly can be explored for unique applications. To download the technical datasheets (TDS) please click on the adhesive name.
| Adhesive | Viscosity [mPas] | Base | Curing | Substrates | Special Properties |
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| 500 - 800 (Brookfield LVT, 25 °C, Sp. 3/30 rpm) | acrylate | UV VIS secondary heat cure |
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| 3,000-6,000 (Rheometer, 25 °C, 10s^-1) | acrylate | UV VIS secondary heat cure |
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| 70 (Rheometer, 25°C) | acrylate | UV VIS |
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| 2,100 (Rheometer, 25°C, 10 s^-1) | acrylate | UV/VIS |
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| 170 (Rheometer, 25°C) | acrylate | UV VIS |
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*UV = 320 – 390 nm VIS = 405 nm
Our Bonding and Curing System Solutions
Hoenle provides complete adhesive bonding solutions for optimal production efficiency and productivity. Pairing Hoenle UV Medical grade adhesives with the appropriate Hoenle UV or LED curing system ensures that the adhesives are thoroughly cured in the shortest possible cycle time. Hoenle curing equipment offers a full range of curing wavelengths, adjustable intensities, and is cleanroom compatible. The equipment is programmable with full monitoring capability to maintain the highest level of process control.
Contact And Support
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