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Urethane vs Latex

02/28/2008 5:18 PM

What are some of the main differences between urathanes and latex? Can urethanes be vulcanized?

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#1

Re: Urethane vs Latex

03/01/2008 10:38 AM

Urethane is like a varnish or enamal only harder and more chemical resistant and it is oil based.

Latex is water based paint like what you would paint the walls of your house with.

Vulcanizing involves rubber and urethane is not rubber so I don't think it is suitable for that process.

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#2

Re: Urethane vs Latex

03/01/2008 10:47 AM

I agree with the first poster. I dont believe urethanes can be vulcanized. Suggest Googling it if you havent already.

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#3

Re: Urethane vs Latex

03/01/2008 11:14 AM

Urethanes, Latex, Silicone caulking all out gas solvents, oil or water based. Rubber is sulphur crosslinked hydrocarbon chains using heat. The more cross-links the harder and stiffer the product.

Or outgassing set and thermoset for cures, two different systems.

Some epoxies are both. Long out gassing times sped up by heat setting. But they are designed for this because cross-links determine the products properties and if the outgassing is to fast the cure is incomplete leaving a sticky mess.

There are probably a lot more forgiving products out now. (I'm a little dated)

Brad

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#6
In reply to #3

Re: Urethane vs Latex

03/08/2008 1:48 PM

is that a yes or no?

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#7
In reply to #6

Re: Urethane vs Latex

03/08/2008 8:27 PM

No it can't be vulcanised. Different cross linking.

But like I said I,m out of date. I've only studied sulphur vulcanized rubber. I've shot both water based and solvent based Urethane. If it wasn't for the organic volatiles I prefer the solvent but the water based is a lot less hassle.

Brad

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#4

Re: Urethane vs Latex

03/01/2008 1:48 PM

Yes, there is a substantial difference. Latex is a white, tacky, aqueous suspension of a hydrocarbon polymer occurring naturally in some species of trees, shrubs or plants or made synthetically. Polyurethane is a thermoplastic polymer that can be used as fiber, coating, elastomer and as foam.

Vulcanization is a term used to cure (vulcanize) rubbers or elastomers with heat or not heat, with sulfur or without sulfur because a large number of compounds which do not contain sulfur can vulcanize rubbers; these fall generally into two groups: Oxidizing agents and generators of free radicals. There is not a single method or chemical reaction of vulcanization.

Urethane is a chemical compound called ethyl carbamate, its structure is typical of the repeating unit in polyurethane.

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#5

Re: Urethane vs Latex

03/04/2008 4:08 PM

Polyurethane is the reaction product of a disocyanate and a hydrogen donor. By hydrogen donor I mean compounds containing hydroxy groups or amine groups (there are others). They can be made thermoplastic, or thermoset. The thermoset ones are active chemicals, you have to mix an A and B together to get a reaction. Some coatings react with moisture to cure. Some coatings polyurethanes are prereacted then dispersed in water, they do not chemically react, just dry.

The thermoplastics are melted and molded and do not cure by reaction.

The thermoplastics do not vulcanise, the thermosets do react the A and B but do not vulcanise like natural rubber does.

Latex is a very general term and may mean a substance like natural rubber which can be vulcanised with generally sulfur base chemicals, or it may mean the synthetic resins used in such products as latex paint which generally just dry.

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