Sealants without Methyl Ethyl Ketoxime

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Discussion Overview

The discussion centers around the search for sealants that do not emit Methyl Ethyl Ketoxime (MEKO) or other toxic byproducts during curing. The context includes practical applications, specifically sealing gaps to prevent ants from entering a home.

Discussion Character

  • Exploratory, Technical explanation, Debate/contested

Main Points Raised

  • One participant expresses concern about the toxicity of MEKO emitted by RTV Neutral silicone sealants and seeks alternatives that do not release toxic byproducts.
  • Another participant suggests that there are many types of sealants available and questions what alternatives the original poster is comfortable using, noting that general purpose silicone sealants typically do not require respirators for safety.
  • A link is provided to a source discussing new generation MEKO-free bonding and sealing products, although availability is uncertain.
  • A participant explains the differences between acetic cure and neutral cure silicone sealants, detailing that acetic cure releases acetic acid, while neutral cure typically produces MEKO, suggesting that acetic silicones may be a safer option for certain applications.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the best sealant alternatives, and multiple viewpoints regarding the safety and types of sealants remain present.

Contextual Notes

There are limitations regarding the availability of MEKO-free products and the specific safety measures associated with different types of sealants. The discussion does not resolve the question of which sealant is definitively safe or effective for the intended application.

Cobul
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I found out the silicone sealants with RTV Neutral (Room Temperature Vulganizing) curing method emits Methyl Ethyl Ketoxime which can be toxic when inhaled.

I just want to seal my the bottom of the door edge to avoid ants outdoor from getting inside.

What sealants can you use that doesn't contain any Methyl Ethyl Ketoxime or toxic byproduct when it is curing? Just enough to prevent ants from getting inside via the small gap.
 
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There are many, many different types of sealants
If you are nervous about using such a widely used product as silicone sealant you probably need to tell what you ARE comfortable using.
I had a quick look at some SDS for general purpose silicone sealants and all they recommend is to use gloves (for obvious reasons); there are no mentions of e.g. using a respirator even in enclosed spaces meaning these are not generally considered to be hazardous to handle.
 
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Typical silicone sealants usually either come in "acetic cure" or "neutral cure".

Acetic ones will say on the label that they release acetic acid during the reaction of methyl triacetoxysilane, and will release the characteristic vinegar scent of acetic acid.

Sometimes this acetic acid is unacceptable in certain applications like electronics, as it may cause corrosion.
In this case, "neutral cure" chemistry is used.

This releases no acid when curing, and this is where you will typically find an oxime such as methyl ethyl ketoxime produced.

If you're concerned about the MEKO byproduct, one of the common acetic silicones won't release it.
 
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