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JW Latex Consultants (and Rubber Consultants,乳胶顾问) offer solutions to your problems in Natural Rubber latex and Synthetic Rubber latex processing and the manufacturing of latex products (condoms, catheters, medical gloves, baby teats and soothers, toy balloons etc) Quick answers through e-mails are possible at reasonable cost.

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Send Your Enquiry and Orders To: woonsungliang@yahoo.com.sg

Problem Solving Through E-Mails with John Woon Latex Consultants Is Possible
可以通过电子邮件与JW乳胶顾问来解决问题

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Friday, August 29, 2008

4th International Rubber Glove Conference & Exhibition 2008 in Kuala Lumpur, Malaysia (2 September - 4 September 2008)

The following 16 papers will be presented during the 4th International Rubber Glove Conference and Exhibition in Kuala Lumpur, Malaysia:

1) Exporting Medical Gloves to US: Latest FDA Requirements and Guidance
2) Medical Device Directive and CE Marking
3) FITkit® Technology and a New "Safety Limit" ~ The Clear Way to Overcoming The Latex Allergy Threat of Natural Rubber Latex Products
4) Quantitative Determination of Antioxidants in Latex and Latex Compounds
5) Regulatory Requirements in Exporting Medical Gloves to China
6) Understanding Colloidal Properties and Nano Technology for Glove Manufacturing
7) Environmental Management in Glove Manufacturing ~ Anaerobic Treatment for Wastewater
8) Nitrile Polymer Design and Modes of Crosslinking for Quality Barrier Protection
9) Effect of New Vulcanizing Method on Nitrile Dipping Products
10) Novel Sustainable Accelerator Systems for Natural and Synthetic Polyisoprene Latex Without Added Zinc Oxide
11) New Generation XNBR Latices for Thin Films with High Performance and Advanced Glove Processing
12) Role of Nano-Zinc Oxide Dispersion in Latex Technology
13) LoproL ~ Sustainable Natural Material for Latex-based Medical Products
14) Managing Productivity for Global Trends in Supply and Demand of NBR Nitrile Latex
15) Improving Business Development by Recovering Energy from Biomass, Waste and Residues
16) Wake Up and Smell the Rubber ~ Supply and Demand and Price Trends of Natural Rubber Latex

Tuesday, August 26, 2008

Training Offered by JW Latex Consultants

Glove and Condom Manufacturer: We understand that you do conduct on-site training for factories and would be grateful if you could tell us what this entails.

John Woon (Senior Latex Consultant): Our training using Powerpoint presentation generally includes the following:

1) Natural rubber latex properties and stabilities
2) Latex dipping technology
3) Trouble shooting for defective gloves and condoms
4) PV vs Post-vulcanisable latex compounds
5) Nitrosamine in rubber products.
6) Allergen, antigen, antibodies, Type 1 and Type 4
reaction, anaphylactic shock
7) Nitrile latex technology
8) Polychloroprene latex technology

To get an idea of the content of my Powerpoint slides, please view some of the samples in the following video: (Sorry the reproduction is not very clear)









You are at the site for answers and solutions to all your problems in natural rubber latex processing and manufacturing of industrial, household and medical gloves, condoms, catheters, baby teats and baby pacifiers, toy balloons, latex foam products, latex threads etc.

Thursday, August 21, 2008

Natural Rubber price levels off

According to an article in Tyres & Accessories, "The price of natural rubber is finally starting to level off, after increasing 40 per cent in the last year. According to Deutsche Bank analysts, the price is now likely to level off at around US$2.8/kg, having risen to US$3.3/kg (RSS3 grade) by June 2008. “If natural rubber price follows recent drop of oil price, it could drop to US$2.6/kg (the average of the last 18 months)," the analysts observed. The news is likely to be greeted by a sigh of relief by tyre manufacturers who had been witnessing erosion in their operating profits due to increased raw material prices."

You are at the site for answers and solutions to all your problems in natural rubber latex processing and manufacturing of industrial, household and medical gloves, condoms, catheters, baby teats and baby pacifiers, toy balloons, latex foam products, latex threads etc.

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Dipping problems of natural rubber latex catheter balloons

Latex Catheter Manufacturer: I am a process engineer for a medical device company. Our products include various types of catheters and we also make balloons for our own catheters. Recently, we are attempting to qualify a new latex mixture (post-vulcanised) from a new supplier for use on the manufacturing of balloons for catheters. We are successful for one batch of latex. The formers/mandrels are dipped in the coagulant (calcium nitrate + ethanol) for a while and allow to dry before dipping in latex vertically. However when we tried the same process for 2nd and 3rd batch of latex, we are unable to get the correct shape of the balloons using the same process. The following deviations were observed:

(1) Uneven latex pick up at the tips of the formers (see photo1)
(2) The balloon is much thinner at the sharp edge of the tip (see photo 2)

The latex from the 2nd and 3rd batch also seems to be more watery or less dense even though we did tried to control the viscosity to make sure that they are the same. Our supplier seems to lack the technical expertise to help us resolve this issue and claim that all their latex is within their spec. I somehow come across your website and is impressed by your passion and knowledge on latex technology as well as your willing in sharing invaluable information and knowledge. I hope you can advise us on the possible additive we may add to resolve this issue or spec of latex we should look into. Please revert back to me if more information is needed.

We also attached the latex test results and specification.

Hope to hear from you soon. Thanks.

John Woon (Senior Latex Consultant): You mentioned that you're using a post-vulcanised latex. Technically, there's no such thing as post "vulcanised" latex compound. I presume you meant post-vulcanisable latex.

If this is what you're using, I would recommend you try prevulcanised latex (i.e. PV latex) for more consistent processing properties.

Assuming all other factors being within your normal controls except the latex, the deviation of your product quality could be due to:

1) Inconsistent latex stability (e.g. MST, viscosity)
2) Inconsistent latex vulcanisation state. (I'm assuming you add the curatives to the latex yourself or your supplier supply the latex and chemicals for you to do the mixing)
3) The latex was not properly homogenised before use.

Other factors besides latex properties include:


1) Excessive collection of coagulant at the tip, especially when the former are not inverted or the inverting of the formers was delayed
2) Too fast withdrawal of formers from the latex. Ideally the speed of withdrawal should equal to the speed of the latex flowing downward.
3) Formers are too cold.
4) Dirty former tip
5) Excessive drainage of coagulant away from the tip, assuming you invert the formers after coagulant tip and the formers are not preheated.

I've checked your latex test report and found that the TSC (~57%) is unusually low if it is the standard centrifuged latex concentrate. Also, the pH (~12.0) is abnormally high.

The specification of your latex leaves a lot to be desired. If you really want to control and monitor your latex quality well, you should include all the following:

1) TSC
2) Alkalinity
3) MST
4) VFA number
5) KOH number
6) Viscosity
7) Total Magnesium content

Natural rubber latex could sometimes be difficult to handle because the inherent properties and hence the processibility might change with different batches of latex despite the various parameters being within the agreed specification. Also, there are "tricks" some producers could resort to in order to make a "bad" latex meeting your specification. You must therefore make a point to know who the producer is if you are now buying from a trader and check their background.




You are at the site for answers and solutions to all your problems in natural rubber latex processing and manufacturing of industrial, household and medical gloves, condoms, catheters, baby teats and baby pacifiers, toy balloons, latex foam products, latex threads etc.

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Wednesday, August 06, 2008

Vulcanisation and thickening of positively charged Natural Rubber and Nitrile latices (latexes)



Manufacturer: We managed to produce positive charged natural rubber latex and Nitrile latex. This is for coating and impregnating textiles which usually have negative charges. To our satisfaction, we found the adhesion of the latex to the textile to be superior compared to normal centrifuged natural rubber latex concentrates (i.e. CL 60 HA or LATZ) and standard Nitrile latex.

However, our problem is that the ageing resistance of the rubber is quite poor. To overcome this we decided to add curing agents to vulcanize the rubber. However we encountered latex stability problem during mixing of the latex compounds. Also, we had problems when we intended to increase the latex viscosity with acrylic types of thickener.

Your suggestions on how we could overcome these problems would be appreciated.


John Woon (Senior Latex Consultant): If you are using conventional dispersing agents for the preparation of your curative dispersions or you are using ready made dispersions from external sources, I won’t be surprised at all that you’re experiencing the latex stability problem you mentioned.

You should use only cationic surfactants and perhaps along with only non-ionic surfactants as your dispersing agents because your latex particles are positively charged, unlike the usual natural rubber and nitrile latex concentrates. Examples of the former are quaternary ammonium compounds such as cetyl trimethyl ammonium chlorides and cetyl pyridium bromide while examples of the latter are condensation products of ethylene oxide with fatty acids, alcohols or phenols.

As regards the latex thickeners, you should not use anionic type like sodium or ammonium polyacrylates. Your better bet should be those based on methyl cellulose.







You are at the site for answers and solutions to all your problems in natural rubber latex processing and manufacturing of industrial, household and medical gloves, condoms, catheters, baby teats and baby pacifiers, toy balloons, latex foam products, latex threads etc.

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What has the bouncing ball to do with tyres?

Latex Gloves Educational Articles from the Malaysian Rubber Export Promotion Council

How do you select your medical gloves?

Rubber Chemicals: Carcinogenicity, Mutagenicity, Clastogenicity.

Why is Compression Set measurement important?

Assessment of Latex Stability

Joule Effect

Poor Flocking Quality Of Household Gloves

Creaming of Latex

What is Vulcanization?

History of Latex Dipped Products

Applications of Prevulcanized Latex

Defoamer Creating Havoc in Glove Factory

Problems With Milling Rubber Chemicals

Medical Gloves From Guayule Latex

Introduction to SMG Gloves

 

 

Click on The Following Links to Read More Articles:

[Advantages of Vulcanization] [Applications of PV Latex] [Bacteria and Latex] [Chemical Toxicity] [Cross-Linking Density] [Biodegradability] [Black Articles] [Blooming] [Bouncing Ball] [Compression Set] [Condoms] [Creaming] [Defoamer] [FDA] [Fatty Acid Soaps] [Flame Retardant] [Flocking] [Food Packaging] [Glove Demand] [Glove Selection] [Guayule Latex] [History of Gloves] [Joul Effect] [Latex Stability] [Latex Thread] [Milling Problem] [MREPC Articles] [Nano Polymer Particles] [Nano ZnO] [Polychloroprene] [REACH] [SMG] [Storage Hardening] [Vulcanization] [Vytex] [Yulex]

Disclaimer:
The information and data contained in this site are believed to be accurate and reliable. However it is the responsibility of the visitors and readers to satisfy themselves that the information is workable under their own processing conditions. Hence the owners of this site make no warranties concerning the suitability of the information given in this site.

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