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.



[Advantages of Prevulcanization] [Air Permeability] [Applications of PV Latex] [Bacteria and Latex] [Chemical Toxicity] [Cross-Linking Density] [Biodegradability] [Black Articles] [Blooming] [Bouncing Ball] [Compression Set] [Condoms] [Copper Staining] [Creaming] [Defoamer] [FDA] [Fatty Acid Soaps] [Flame Retardant] [Flocking] [Food Packaging] [Glove Demand] [Glove Discoloration] [Glove Selection] [Guayule Latex] [History of Gloves] [Joul Effect] [Lab Equipment] [“Latex” Definition] [Natural Rubber Latex Stability] [Natural Rubber Latex Thread] [Milling Problem] [Mixing Equipment Directory] [MREPC Articles] [Nano Polymer Particles] [Nano ZnO] [Permanent Set] [Polychloroprene] [REACH] [SMG] [Storage Hardening] [Stress Relaxation] [Surfactants Directory] [Tensile Properties] [Vulcanization] [Vytex] [Yulex]


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Wednesday, September 28, 2016

Natural Rubber Latex Adhesives vs Solvent Based Adhesives

Manufacturer: My company is manufacturing rubber-based adhesives. Recently I was asked to venture into natural rubber latex based adhesives to replace some of our solvent based adhesives. What are the general advantages of latex based adhesives?

John Woon (Senior Latex Consultant): Generally, while latex based adhesives are environmentally friendly, it also offers the following advantages over the solvent based adhesives:

1) Latex has a low viscosity at high solid content. For instance, NR latex concentrate with a total solid content of about 60% has a viscosity of only 150 to 200 mPa.s whereas a rubber solution of about 17% has a viscosity of 60,000 to 100,000 mPa.s.

2) The low viscosity of latex allows it to be easily applied by spraying and roller coating.

3) The high solid content of latex allows for high coating weight  (dry) to be achieved with minimal number of coating.

4) For solvent based adhesives the rubber is frequently masticated to breakdown of the rubber molecules before use to ease dissolution in solvents. This results in the weakening of the cohesion strength of the adhesives. Latex based adhesives do not have this problem.

5) Owing to the absence of solvent, latex adhesives do not pose as health and fire hazards. There is no need for expensive procedures and precautionary actions such as the use of flame-proof motors, maximum ventilation, flame-proof lighting and segregation from other production processes.

Tuesday, September 20, 2016

Continental Brings Dandelion Rubber to Commercial Vehicles

According to Rubber World, a technical revolution is now available for commercial vehicles. Continental is for the first time unveiling components and tires for trucks and buses made from natural rubber derived from dandelion roots.

At the forthcoming International Motor Show Commercial Vehicles, the technology company will be showcasing for the first time truck tires made from this innovative and sustainable dandelion rubber: Conti EcoPlus HD3, which were manufactured in summer 2016.

On show will be also the prototype for an engine mount that links the power train with the chassis. This insulates the structure-borne noise from the engine, thereby enhancing ride quality and driver safety.

Another sampled product will be the first example of an intermediate propeller shaft bearing made from the new material, named Taraxagum. This stabilizes and minimizes the transmission of vibrations to the chassis.

As an agricultural crop, dandelions have the potential to become an alternative, environmentally friendly raw material source, thereby helping to reduce our dependency on traditionally produced natural rubber. But that is not all: The plants can be cultivated in northern and western Europe, which makes transportation routes to the European production sites much shorter and contributes to the sustainable use of existing resources. Continental has already recognized this potential, and as early as 2014 launched the first premium winter tire featuring a tread made from pure dandelion rubber.

Tuesday, August 30, 2016

Compounding for Low Temperature Applications of Natural Rubber Products

Manufacturer: We are manufacturers of a range of natural rubber based products intended for applications at low temperature during winters. However, we have not been very successful because the products tend to harden at low temperatures. Please give us some clues on how to overcome this problem.
John Woon (Senior Latex Consultant): Owing to the stereoregularity of the natural rubber molecules, the rubber tends to crystallise and lose elasticity with increased stiffness when subjected to  proloned exposure to low temperatures.

I suggest you conduct some experiements by increasing the levels of sulphur and accelerators, particularly sulphur. Adding a plasticizer such as di-iso-octyl sebacate, would be advantageous. Replacing some of the natural rubber with "super processing rubber" made partially from prevulcanised latex such as PA 80, could also heelp.

Friday, August 05, 2016

Technical Papers to be Presented in the 8th International Rubber Glove Conference and Exhibition in Kuala Lumpur , Malaysia

The papers confirmed for the 8th IRGCE 2016 ( from September 6 - 8, 2016) are as follows:
  1. Beyond The Horizon: Longer Term Opportunities of the Rubber Gloves Market by No Dock Moung of ICIS Consulting Asia, Singapore
  2. Novel Room Temperature Safe Cure Compositions for Use in Synthetic Polyisoprene Latex by Ranvir S. Virdi by Robinson Brothers Limited, United Kingdom
  3. Important Changes in European Testing Requirements: EN 374-1, EN 16523-1, EN 420 and the new PPE Regulation by Martin Heels of SATRA Technology, United Kingdom
  4. Enhanced Process Effective and Skin Friendly Solutions for the Production of Dipped Goods using Synthetic Poly-isoprene Based Lattices by Adeline Kung of Kraton Polymers, Malaysia
  5. Insights into Film Deposition and Consolidation During the Thin Glove Coagulant Dipping Process by Dr Robert Groves and Dr Alex Routh of United Kingdom
  6. A Scientific Investigation on Extractable Residues in Various Rubber Gloves (Natural and Synthetic) by Dr Ng Thian Hong of Synthomer, Malaysia
  7. Attributes of Good Former in Glove Dipping Process by Howard Woon of Gateway Industrial Corporation Sdn Bhd, Malaysia
  8. Performance of Graphene Materials Incorporated into Latexes via the Conventional Mixing Route by Dr Mok Kok Lang of Malaysian Rubber Board, Malaysia
  9. Latex-T: A Rapid Diagnostic Test for Allergens in Natural Rubber Latex Products by Dr Roslinda Sajari of Malaysian Rubber Board, Malaysia
  10. State of Glove Affair by Denis Low Jau Foo of Malaysian Rubber Glove Manufacturers Association (MARGMA), Malaysia
  11. Use of Vulcanization Accelerator-Free Rubber Gloves in Patients with Rubber Accelerator Contact Dermatitis by Dr Kayoko Matsunaga of Fujita Health University School of Medicine, Japan
  12. Future Development of Alternative Sources of Natural Rubber: Guayule or Kazakh Dandelion by Dr Serge Palu of CIRAD, France
  13. Infection Control in Hospital Settings in Relation to Disposable Medical Products Particularly Medical Gloves by Patty Taylor of Ansell, USA
  14. Bio-add and Bactolex as New Additives for Biodegradable Natural Rubber and Nitrile Rubber Gloves by Dr Azura binti A. Rashid of University Science Malaysia, Malaysia
  15. Hydrophilic Polymers as Protein Removers for Natural Rubber Latex by Vijitha Dhanapala of Lalan Rubbers (Pvt) Ltd., Sri Lanka
  16. A Practical Approach to Making Nitrosamine & Nitrosatable Safe Latex Products by Anil Skariah of Thaimed Baby Products, Thailand
  17. Prospective Developments In Latex Products: Applications of Single Wall Carbon Nanotubes by Ekaterina Gorbunova of OCSiAL, Russia
  18. Conductive Rubber Films by Dipping Process by Dr Siby Varghese of Rubber Research Institute of India, India.
A half day seminar on "Analytical Methods for Latex Dipped Products" will be held on the 8th of September 2016 and to be conducted by Professor Dr Ho Chee Cheong and Dr Eng Aik Hwee.

Tuesday, July 26, 2016

Effect of Cross-linking - A Very Important Aspect of Rubber Technology

Students: We have just started our training course on vulcanization and cross-linking of Natural Rubber. Can you please let us know in general the effect of cross-linking on the behavior of the vulcanized rubber?

John Woon (Senior Latex Consultant):
Please see the Table above for the "Changes in Rubber Properties with An Increase in Degree of Cross-Linking".

JWLatexConsultants.com Hacked and Infected!!

John Woon (Senior Latex Consultant): Please be informed that our sister website, JWLatexConsultants.com has been hacked and infected. Please do not visit this site for the time being. We apologize for any inconvenience caused.

Instead, please visit http://woonsungliang.wix.com/jw-latex-consultants

Monday, June 27, 2016

Sodium Soaps vs Potassium Soaps as Latex Stabilisers

Manufacturer: We use both KOH and NaOH for making our fatty acid soaps as  stabilizers for our latex compounds. We are experiencing more problem with sodium soaps especially when there is a change in ambient temperatures. Why?

John Woon (Senior Latex Consultant): Simple. The reasons are as follows:

1) Sodium soaps are less soluble than potassium soaps.
2) Sodium soaps are harder than potassium soaps.
3) Sodium soaps tend to gel at lower temperatures although this phenomenon is reversible.

Therefore from technical point of view, there is no reason why you should use sodium hydroxide although it might be cheaper than potassium hydroxide.

Monday, June 06, 2016

Blowing Agent (Foaming agent) for PVC Plastisol

Manufacturer: We are manufacturers of products based on PVC plastisols including PVC gloves. We are now venturing into making foamed products but our initial work has not been successful. We believe that this could be due the wrong choice of blowing agent as our processing temperature is quite low at about 120 C.  We would appreciate very much if you could suggest some suitable blowing agents for our use.

John Woon (Senior Latex Consultant): Some of the most common blowing agents used for rubber and plastic do have high decomposition temperatures of more than 150°C which would of course not work satisfactorily if your processing temperature is only 120°C.

I suggest you evaluate the following:

Azo nitriles, bezene sulphonic acid hydrazide and ditroso pentamethylene tetramine.

Let me know the outcome in due course.

Thursday, May 26, 2016

Wetting Agent in Coagulant

Manufacturer: We are in the process of improving the wetting property of our coagulant mix to overcome pinhole and thin spot problems. We would appreciate very much if you could advise us on the temperature, level of wetting agent, cloud point, etc.

John Woon (Senior Latex Consultant): You need to pay attention on the following factors:

1) Temperature of the coagulant should be as high as possible but not exceeding the could point or 65°C to achieve maximum wetting.

2) Level of wetting agent is to be high enough but not to the extent of causing foaming and retarding drying.

3) You should determine the could point on your own instead of just relying on surfactant suppliers' cloud points because salts such as calcium nitrate and other ingredients in the coagulant mix can affect the cloud point.

Details has been sent to you separately at your request.

Thursday, May 19, 2016

Reducing Ammonia Content of Latex Concentrate with Formaldehyde

Manufacturer: We are manufacturing dipped tubes, for medical in small scale.
Can we add formaldehyde to reduce the concentration of ammonia in high ammonia latex, so that even dip could be produced?
John Woon (Senior Latex Consultant): Yes, you can add formaldehyde to reduce the ammonia content in the latex.When you add formalin to the latex, pH would drop and latex would tend to destabilise. Therefore you need to add a non-ionic surfactant first. Stir for two hours before adding formalin.

You can try Emulvin W or equivalents as the surfactant. If you continue to encounter stability problem such as viscosity rise it could be due to the latex quality problem, in which case I suggest you remove the ammonia by stirring with a fan over the surface of the latex.

Thursday, April 21, 2016

Curatives for the Vulcanisation of Nitril Rubber

Manufacturer: We are manufacturing rubber parts using dry natural rubber (SMR) via compression molding and are about to conduct some trials using dry carboxylated nitrile rubber. We would be obliged if you could give us some guide lines in terms of curatives compounding.

John Woon (Senior Latex Consultant): For general applications, you can used practically the cure systems for both NR and SBR such as thiazoles and sulphenamide cure system. For high temperature applications and also where low compression set is required, both thiuram and peroxide cure systems should be used.

You should also get the advice from the rubber suppliers or manufactueres because the following factors involved in polymerization, etc. are also affecting the vulcanisation of nitrile rubber:

1) Coagulant
2) Emulsifiers and surfactants
3) Polymerization additives
4) Polymer rheology
5) Process aids in polymerization

Friday, April 08, 2016

Blending of Different Latices and Addition of Fillers in Latex Adhesive Compounds

Manufacturer: We are manufacturer of latex-based adhesives. Please give us some general guidance in blending of two different latices and the addition of fillers in terms of latex colloidal stability.

John Woon (Senior Latex Consultant): I suggest you look into the following points:

1) Blending of two different latices (latexes)

1.1) Make sure the pH of both latices are as close as possible. By changing the latex pH, the latex could sometimes be destabilized in which case, it is advisable to add a non-ionic surfactant to that latex before the pH adjustment.

1.2) Latex with smaller particle size would tend to rob the surfactant already present on the particles of latex with higher particle size. Generally, the level of surfactants required for the blend is more than the total amount required for the two individual latex.

2) Filler addition

2.1) You could either add the filler dry or as a pre-prepared slurry to the latex. The former would require higher level of surfactant than the latter.

2.2) The higher the level of filler, the higher is the level of surfactant required.

2.3) Filler with smaller particle size would tend to rob more of the surfactant from the latex particles compared to filler with coarser particles.

2.4) Filler type is important e.g. clay and talc would have less destabilizing effect on the latex compared to calcium carbonate.

2.5) Generally a combination of surfactants performs better than a single surfactant.

Hope this helps.

Tuesday, March 15, 2016

Mechanism of the Leaching Process

Manufacturer: I am the head of the R&D department in a latex dipped products manufacturing company in Sri Lanka. In order for me to understand the importance of leaching, I need to know the mechanism involved during leaching. Can you help?

John Woon (Senior Latex Consultant): Over the years I've studied and analyzed the factors involved in the leaching process so as to achieve the most optimized leaching effectiveness for a variety of dipped products.

I've identified 7 steps which take place in sequence during leaching. I've sent this along with some details of each step to you separately. Please let me know if this is of any help.


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]

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.