Should use neutral silicone sealant or acidic sealant for bonding PVC?

Should use neutral silicone sealant or acidic sealant for bonding PVC?

When bonding PVC materials (such as PVC pipes, profiles, and sheets), neutral silicone sealants are preferred over acidic silicone sealants. The core reason lies in the differences in the composition and compatibility of the two types of sealants with PVC materials. A detailed analysis is provided below:

Key Conclusion: Neutral silicone sealants are the preferred choice for PVC bonding.
Neutral silicone sealants (categorized as “alcohol-type” and “ketoxime-type”) release small neutral molecules (such as alcohols and ketoximes) during the curing process. These do not chemically react with PVC materials, ensuring bond strength while preventing corrosion, discoloration, or embrittlement. They are also suitable for a wider range of applications (particularly indoors and outdoors, and for decorative purposes).

Additional Notes: Key Details to Ensure Bonding
Confirm the PVC Type:
Most common PVC materials (hard and soft) are suitable for neutral silicone sealants. However, please note: If there is oil, dust, or mold release agent on the PVC surface, wipe it clean with alcohol or a dry cloth beforehand, as this will affect the bond strength.
Choose a “Bonding” Neutral Glue:
Neutral silicone sealants are divided into “sealing” and “bonding-sealing” types. If “bonding” is your primary need (rather than simply filling and sealing), choose a product clearly marked “suitable for PVC bonding” or “high-strength bonding” on the packaging to avoid using only ordinary sealants, which may result in a weak bond.
Avoid mixing with other solvents:
When bonding PVC, do not add thinners or other solvents to the sealant. Also, avoid contact between the PVC surface and gasoline, banana oil, etc., as this may damage the PVC structure and affect the bond.