Hot Branded rubber flooring wont solidify

[jgeer]

I am trying to brand a logo into natural rubber flooring. I am using a 400 Watt electric branding iron. I am able to successfully brand the rubber. Prior to branding the rubber does not rub off onto the hands or any other contacted surface. After the logo is branded into the rubber, the rubber rubs off after cooling down. The rubber is made from 100% recycled tires. I contacted the manufacturer, they had no suggestions.

I need to stop the post-branded rubber to solidify and stop rubbing off.

I have tried cleaning the branded area with regular household cleaners with no success. I have not tried acetone or the like since acetone melts rubber.

Any thoughts?

 

[btrueblood]

You've burnt/charred the rubber. How would you remove char from a piece of wood? Sandblast, or other mechanical removal methods - i.e. elbow grease. Or apply a coating, but dunno what would work, maybe a flexible epoxy floor coating.

 

[GrahamBennett]

btrueblood is correct - you've essentially burnt the rubber. What you have inadvertently done is reverted the rubber by heating it to too high a temperature. This reversion has caused the rubber molecular chains to split into smaller lengths (reducing the molecular weight of each) resulting in a sticky mass. By the time you've cleaned all of this off I wouldn't be surprised if you haven't removed all of the information you've just branded on.

You can buy heat resistant rubber patches that can be inserted in the mould along with your uncured rubber compound. These patches already have the information you require moulded onto the surface and are available in black, red, blue or yellow at least. These will cost a fair deal as the mould used will be specific to your company.

 

[mhallin]

Hello,

Your method should work; I have done similar brands myself with good results. I used a brass template which I placed along with the rubber in a press and closed it for two minutes with a temperature of about 200°C (see attached image). I believe you have used a temperature that has been too high or exposed the rubber to heat for too long. Even though I worked with an EPDM rubber which has a higher tolerance against heat compared to NR, I’m sure you could find the right balance between heat and time of exposure.

Alternatively you could ask your rubber manufacturer to make the logo in the vulcanization process (depending on the method used) or use a laser-printer to make the logo.

Good luck!
/Mathias