| Base polymer | VMQ silicone rubber, preferably high-purity or medical-grade where the application requires it | Wide operating temperature capability; good resistance to ozone, ultraviolet radiation, moisture, and aging | Request the polymer type, formulation statement, lot traceability, and applicable compliance documents |
| Curing system | Platinum-cured silicone for low extractables and low residual odor; peroxide-cured material may be acceptable after validated post-curing | Platinum curing generally avoids peroxide decomposition residues, while odor performance still depends on additives, processing, and post-cure conditions | Confirm cure chemistry, catalyst system, post-cure temperature and time, and residual-odor test results |
| Odor performance | Neutral or very low odor after conditioning and post-curing | No universal “odorless” limit applies to every market; odor can be affected by volatile siloxanes, pigments, processing aids, packaging, and storage | Define the acceptance level, sample-conditioning procedure, panel method, and test temperature in the purchase specification |
| Hardness | Select according to sealing, flexibility, pressure, and installation requirements | Common silicone tube hardness range: approximately 30–80 Shore A; exact values depend on formulation | Specify Shore A hardness and tolerance, with testing to ASTM D2240 or ISO 48-4 |
| Temperature range | Use a validated range based on continuous exposure, peak exposure, pressure, and fluid contact | Many silicone tubes are used approximately from −50 °C to +180 °C; some formulations support short-term exposure near +200 °C | Obtain the supplier’s continuous and intermittent temperature ratings for the exact tube construction |
| Pressure capability | Use reinforced construction for elevated pressure or pulsation | Burst and working pressure vary significantly with inner diameter, wall thickness, hardness, temperature, reinforcement, and service life | Require working-pressure, burst-pressure, vacuum, bend-radius, and temperature derating data for the specified size |
| Dimensional control | Controlled inner diameter, outer diameter, wall thickness, ovality, and cut length | Tolerance depends on tube size, extrusion process, tooling, and applicable drawing requirements | Approve a dimensional drawing and inspection plan; verify dimensions using calibrated gauges |
| Mechanical properties | Balance tensile strength, elongation, tear resistance, and compression set for the application | Typical unreinforced silicone compounds may provide tensile strength around 5–12 MPa and elongation around 200–700%, depending on grade | Request lot-specific test data using ASTM D412 or ISO 37, ASTM D624 or ISO 34-1, and compression-set testing to ASTM D395 or ISO 815-1 |
| Fluid compatibility | Verify compatibility with water, air, steam, oils, fuels, solvents, cleaning agents, and process chemicals | Silicone performs well with many aqueous media and environmental exposures but may swell or lose strength in some fuels, mineral oils, and hydrocarbon solvents | Conduct application-specific immersion testing for mass change, volume change, hardness, tensile strength, and visual condition |
| Food-contact suitability | Use a formulation and manufacturing process documented for the intended food-contact market | U.S. food-contact silicone may be assessed under 21 CFR §177.2600; European compliance typically requires applicable food-contact framework, GMP, and national or regional requirements | Request a declaration of compliance, migration or extractables data, and restrictions for food type, temperature, and contact duration |
| Medical or healthcare use | Use medical-grade material only when the device risk assessment and regulatory pathway require it | Biocompatibility is application-specific and cannot be established solely by calling a tube “medical grade” | Check ISO 10993 evaluation, sterilization compatibility, extractables and leachables, change control, and batch records |
| Cleanliness and extractables | Low-particle, low-residue production with controlled washing, drying, packaging, and post-curing | Cleanliness requirements should be defined by the process, especially for pharmaceutical, laboratory, semiconductor, and sensitive fluid applications | Specify particulate limits, nonvolatile residue, total organic carbon or targeted extractables where relevant |
| Manufacturing process | Consistent extrusion, controlled curing, validated post-curing, clean cutting, and sealed packaging | Process stability influences odor, dimensions, surface quality, mechanical properties, and extractables | Review process-flow documents, inspection records, calibration controls, nonconformance handling, and change-notification procedures |
| Quality-management standard | A documented quality system appropriate to the intended industry | ISO 9001 supports general quality management; ISO 13485 is relevant to organizations supplying medical devices or related components | Verify certificate scope, validity, manufacturing site, audit status, and product-specific quality controls |
| Packaging and storage | Clean, sealed, light-protected packaging with lot identification and defined storage conditions | Keep away from contamination, excessive heat, direct sunlight, ozone sources, and incompatible chemicals | Confirm shelf life, first-in-first-out controls, packaging material, storage temperature, and transport protection |
| Global documentation | Complete technical file prepared for the destination market and end use | Core documents may include a technical datasheet, certificate of analysis, declaration of compliance, SDS, drawing, inspection report, and traceability record | Ensure documents identify the exact material, size, lot, test method, revision, and applicable regulatory limitations |