Neutral Silicone Sealant — Weatherproof Grade

Curtain wall weatherproof sealing, general construction joints, window and door perimeter sealing, and metal and glass facade sealing. It is an all-weather neutral cure grade for interior and exterior use.

Both are neutral cure weatherproof sealants to GB/T 14683-2017. PR-666 is the higher-specification all-weather grade with a 516 mL/min extrusion rate and 0.6 MPa modulus. PR-111 is the general-purpose grade with a high extrusion rate for labour-saving application on exterior joints.

No. It is a weatherseal product. For load-bearing structural bonding use PR-999 to GB 16776-2025.

GB/T 14683-2017. Test report 2025ME156 is available on request.

Standard OEM and private label MOQ is 1,000 pcs per model, with mixed-model trial orders from 3,000 pcs total and stock items from 500 pcs. Typical lead time is 15–25 days after artwork and sample approval.

A neutral cure silicone sealant releases alcohol or oxime during cure instead of acetic acid. That makes it non-corrosive: it will not etch metal, stain natural stone, attack mirror backing, or corrode the coating on an aluminium frame. PR-666 is a neutral cure weatherproof sealant to GB/T 14683-2017, suitable for glass, aluminium, coated metal, concrete and most common building substrates.

Yes. Because no acid is released, neutral cure grades are the correct choice wherever the joint touches metal, natural stone, marble, concrete, coated glass or mirror backing. Acetoxy (acid cure) grades must not be used on those substrates. For mirror work, specify a mirror-grade neutral product rather than a general weatherproof sealant.

Neutral cure sealants have a much lower odour than acetoxy grades. Oxime-cure products have a slight odour during application and alcohol-cure products are close to odourless. Neither releases acetic acid, so there is no risk of acid staining on stone, mortar or metal. Cure speed is slower than acetoxy — allow the full joint depth to cure before loading the joint.

Yes — neutral silicone caulk and neutral silicone sealant are the same product under two trade words. "Caulk" is what applicators call it; "sealant" is what specifications call it. What matters is the cure system and the performance class, not the name: PR-111 is a neutral cure weatherproof grade qualified to JC/T 485-2007, with a high extrusion rate of 212 mL/min for fast gunning.

Neutral cure covers two leaving groups, and an oxime silicone sealant is the one whose crosslinking reaction releases methyl ethyl ketoxime (MEKO) instead of acetic acid. The alternative is alkoxy (alcohol) cure, which releases methanol and is close to odourless. Both are non-corrosive, so both are safe on aluminium, concrete, coated glass and mirror backing — the practical difference is odour during application and cure speed. The silicone sealant oxime released during cure disperses within hours of application. Tell us the substrate and whether the building is occupied, and we will confirm the leaving group for the model you are quoting.

Yes. A low odor silicone sealant is a neutral cure grade rather than an acetoxy one, because the odour comes from the curing byproduct — acetoxy grades release acetic acid and smell strongly of vinegar. Neutral grades release either alcohol or oxime: an oxime-cure neutral has a slight odour during application, an alcohol-cure grade is close to odourless. In UK and EU specifications you will see the same product written low odour silicone sealant. None of them releases acetic acid, so none of them carries the acid-staining risk on stone, mortar or metal.

A flexible silicone sealant keeps its elasticity because the cured polymer is a rubber, not a plastic — it recovers after deformation instead of creeping. That property is what lets a joint open and close without cracking. PR-111 is a neutral cure weatherproof grade for exterior window, door and facade joints; for joints with larger calculated movement, the premium grade PR-638 has the wider movement capability.

A neutral silicone adhesive is a different specification from a weatherseal, even though both are silicone. PR-111 and PR-638 are weatherseals: they bond to the joint faces in order to seal, but they are not designed to carry load, and using them for structural bonding is outside the specification. For applications where the silicone has to transfer force, use PR-999, which is qualified to GB 16776-2025 for structural glazing.

A non corrosive silicone sealant does not release acetic acid while curing, which is what attacks bare or anodised aluminium, corrodes mirror backing and stains natural stone and mortar. PR-111 is neutral cure, so it is safe on aluminium, concrete and coated glass. The limitation is different: it must not be applied to damp or frosty surfaces, and it is not specified for continuous water immersion.

For a non-structural glazing detail, yes — a glazing neutral silicone sealant and a perimeter weatherseal are both neutral cure and both bond to glass and metal. What you must not do is use a weatherseal where the sealant has to carry load. Structural glazing needs a structural grade qualified to GB 16776; PR-111 is a weatherseal for exterior window, door and facade joints.

A weatherseal neutral silicone sealant is the exterior joint product: it keeps water out and absorbs movement between materials that expand at different rates, while fixings carry any load. PR-111 is used on exterior window and door perimeters, general construction and expansion joints, metal and glass facade weatherproofing, and concrete and masonry joints. It is qualified to JC/T 485-2007, report 2025ME159 available on request.

Concrete and masonry are alkaline and porous, so a neutral construction silicone sealant is the right family — an acetoxy grade would be the wrong choice. PR-111 is neutral cure and bonds to concrete and masonry without attacking them, with 0 mm vertical and horizontal sag so it stays where it is gunned on side and overhead joints. For joints with higher calculated movement, step up to PR-638 or PR-666.