Shore 30A Silicone Rubber

Shore 30A Silicone Rubber: The Soft Grade

Shore 30A silicone rubber occupies the soft end of the practical hardness range for elastomeric seals and molded parts. At Shore 30A, the material has a gel-like, compliant feel that conforms readily to mating surfaces under low closure force — a property critical in applications where excessive compression would damage fragile assemblies or cause discomfort in body-contact uses.

Shore 30A is measured using a Type A durometer per ASTM D2240 / ISO 868. A nominal specification of Shore 30A ±5 covers the practical manufacturing variation of compression-molded and extruded silicone parts.

Typical Applications Requiring Shore 30A

Medical tubing inner liners and soft catheter tips: The low compression force of Shore 30A minimizes trauma during insertion and contact with tissue. Platinum-cured transparent grades allow visual flow monitoring.

Baby nipples and teethers: Shore 30A–40A approximates the softness range preferred for infant comfort in bottle teats and teethers. FDA 21 CFR 177.2600 and LFGB §30/§31 compliance is standard for products exported to the U.S. and EU. The absence of BPA, latex allergens, and phthalates is inherent to silicone rubber.

Wearable device skin-contact surfaces: Continuous skin contact (CGM patches, fitness tracker straps worn 24/7) requires a soft, non-irritating elastomer. Shore 30A silicone is hypoallergenic, sweat-resistant, and non-absorbent.

Low-force pneumatic seals: In low-pressure pneumatic systems (<0.5 bar), Shore 30A seals close under the available spring force without overstressing the housing.

Soft-touch grips and pads: Ergonomic hand tools and medical instrument handles use Shore 30A overmolded silicone to reduce grip fatigue and provide vibration damping.

Mechanical Properties at Shore 30A

At Shore 30A, silicone rubber offers tensile strength of 5–7 MPa and elongation at break of 300–500%, enabling it to stretch significantly before tearing. Tear strength is 10–18 kN/m — lower than harder grades due to the reduced cross-link density. Compression set (the permanent deformation after sustained compression) remains low for properly cured platinum grades: typically <15% after 22 hours at 70 °C per ASTM D395 Method B.

Thermal range: −60 °C to +200 °C continuous. Shore hardness decreases slightly at elevated temperature (approximately −1 to −2 Shore A per 20 °C increase) and stiffens slightly at low temperature, but remains elastomeric throughout the stated range.

Certification Options for Shore 30A

FDA 21 CFR 177.2600: Platinum-cured, post-cured Shore 30A grades suitable for repeated food contact. Required for baby products and food processing seals in the U.S. market.

LFGB §30/§31: German and EU food-contact certification required for baby products and kitchen items exported to Germany. Includes sensory testing (no taste/odor transfer) in addition to migration limits.

USP Class VI: Required for pharmaceutical and medical device applications. Systemic, intracutaneous, and implantation biological reactivity tests must be passed.

RoHS/REACH: Shore 30A silicone base polymer complies inherently; confirm pigment and additive declarations with your supplier.

Sourcing Guidance

When ordering Shore 30A silicone, specify: Shore hardness 30A ±5 (or tighter if needed), cure system (platinum preferred for medical/food applications), transparency requirement, post-cure requirement, and certification documents needed. MOQ is typically 10–25 kg per grade and color.

Contact us to verify certification documents and request Shore 30A samples for your application.