Bloom problems of household gloves

Manufacturer: We are a manufacturer of natural rubber household gloves. Can you give us advice/recommendations on how to get rid of "blooming" issue on the
surface of rubber gloves?

JohnWoon: Bloom can be classified as "True Bloom" and "Bloom-like Phenomena". In order to ascertain whether your problem is due to true bloom, you have to ask yourself the following questions:

1)Does the bloom develop over time i.e. on storage?
2)Does it disappear on heating?
3)Can it be removed by wiping with solvent?

If the answers to these questions are all "Yes", you're having a true bloom problem.

For true bloom to occur, the chemicals concerned must have a limited but appreciable level of solubility in the rubber. Also, they must be present at a level or concentration greater than the said solubility at the temperature of use or storage.

Briefly the mechanism involves the crystallization of the chemical as the vulcanized rubber cools down. As the crystals grow within the rubber matrix, regions of strain around the crystals are formed. As a result, the tendency is for the crystals to move towards regions where there is lesser strain, namely the rubber surface.

Curatives that bloom are mainly sulphur, Zinc dithiocarbamate (diethyl being the worst culprit) and some thiazoles.

Ratios of sulphur:accelerator:ZnO:antioxidant, types of accelerators and degree of cure are all important factors to consider in order to prevent blooming. Chemical blooms are the major complaints from users of household gloves due to Type IV allergy reaction, namely delayed contact dermatitis.

One would usually observe a badly bloomed product to have lesser surface tack compared to one that has no bloom for obvious reason. Of course the resultant tackiness with a "non-blooming" formulation could be easily overcome by other means.

Having said this, you have to be aware also of the possibility of "bloom-like" problems due to other factors such as modified bloom (e.g. reaction between Zinc stearate and water vapour), surface degradation, filler bloom, surface contamination, frosting etc.

More in-depth recommendations with suggested formulation to overcome blooming and tackiness problems, improving heat ageing and detergent resistance are available from JohnWoon Consultants.

You are at the site for answers and solutions to all your problems in natural rubber latex processing and manufacturing of medical gloves, condoms, catheters, baby teats and baby pacfiers.

The search for a non-allergenic Natural Rubber (Hevea Brasiliansis) latex stops here?

A USA based company, Vystar Corporation has developed a new low-allergen natural rubber latex (NRL) called Vytex that they believe could be the key to recapturing markets that are currently being lost to synthetic polymers.

Test results obtained to date consistently show that the Vytex technology reduces antigenic proteins to levels considered undetectable by the most widely used standard tests. Importantly, denaturing - rather than removing, - the proteins results in a product that meets or exceeds the desirable chemical and physical properties of NRL.
Vystar gave the follow statistics:

1) The cost for non-latex gloves passed along to the healthcare industry can be two to three times that of Vytex surgical gloves.
2) The cost of synthetics rises with the cost of petroleum products.
3) Vytex's marketability coupled with the added focus of increased output in Southeast Asia, makes it an excellent alternative to untreated NRL as well as to the synthetics.
4) Vytex is a natural choice for the $912 million examination glove,
$291 million surgical glove and $384 million condom industries.

Vystar announced last month (August 2006) that Revertex Malaysia, the world's largest producer of prevulcanized rubber lattices and post vulcanizable latex compounds, will be the first to produce Vytex.

You are at the site for answers and solutions to all your problems in natural rubber latex processing and manufacturing of medical gloves, condoms, catheters, baby teats and baby pacfiers.

Processing problems with natural rubber latex condoms

Manufacturer: Can you give short term (3 to 6 months) consultancy service to our company through e-mails?

We are condom manufacturer with technical in put from Korea but are always having oft-repeated problems with stripping of the condoms from the formers. What are your best recommendations?





There are some customers of ours asking for multi-cloured "rainbow" condoms. Can you help?

JohnWoon: Yes, indeed. Most of my services are offered through e-mails with only ocaasional factory visit. I give a step-by-step approach in problem solving and/or improving the manufacturing processes of latex products including condoms.

I could give only a general approach to this problem in my Blog. Should you need more in depth solution, we could consider this as a project under my consultancy services. However by reading my Blog, you could probably solve your problem yourself tomorrow!

The following are the factors you should look at as regards your stripping problem:

pH of the leaching water, stability/soap level of both your incoming latex concentrates and your final latex compounds and the temperature of the final oven just before stripping.

The condoms should not be too stiff and over dried that could induce the undesirable "clinging" of the rubber to the formers. There should be a designed and controlled elasticity of the dried rubber through proper designing of your compound formulation.

As regards your multi-coloured condoms, I have a ready answer for you to work on. I'd discuss the details if you're interested in working on this as a short term project. You have to be careful in the choice of pigments though, from the point of view of both toxicity and latex stability.

You are at the site for answers and solutions to all your problems in natural rubber latex processing and manufacturing of medical gloves, condoms, catheters, baby teats and baby pacfiers.