Storage Conditions of Natural Rubber Products

Manufacturer: We have just received a complaint from one of our major customers regarding the shelf-life of our natural rubber products in their warehouse. We have investigated our formulation and manufacturing process and found that both are already at their optimum levels. Careful design and curatives and antioxidant system had been adhered to. We would appreciate if you could offer further assistance.

John Woon (Senior Latex Consultant): Maybe you should help your customer by advising them on the conditions of storage for your products.

Rubber products can normally be stored for many years without any loss of their inherent properties provided the following precautions are taken:

1) Do not deform the products to prevent stressing the rubber.
2) Do not expose the products to elevated temperatures for long period. If possible do not exceed 35C.
3) Do not expose the products to light i.e. direct sunlight and artificial light. If possible store the products in the dark.
4)  The products should be properly wrapped and covered also to minimize exposure to air (oxygen) and ozone. Ozone is particularly harmful. The warehouse should not have any electrical equipment that can generate ozone such as high-voltage equipment, electric motors and mercury vapour lamps.
5) Excessive humidity and moist condition especially due to condensation should be avoided.
6) Do not allow the products to come into contact with brass, copper, iron, solvents, oil, greases, etc.
7) Do not unduly store the products for too long by ensuring the stocks are used in rotation.

Zinc Oxide in Natural Rubber Latex

Students: We are a group of students studying the effect of ZnO in ammoniated natural rubber latex concentrate. We hope you could help us with some information on the solubility of ZnO in natural rubber latex especially the effect of pH.
 
John Woon (Senior Latex Consultant): I am assuming you are already familiar with the phenomenon of "ZnO thickening due to Zinc-amine complex".

Studies had been done on the factors controlling the solubility of ZnO in Hevea natural rubber latex using model solutions containing ammonia and ammonium salt at a given pH. It had been found that the solubility of ZnO in the latex is proportional to the total concentration of ammonia and ammonium salt.

Also, at a constant concentration of free ammonia and ammonium ions, maximum solubility of ZnO can be achieved at a pH of 9.5.

European Commission Backs ECHA on Phthalates in Toys

The European Commission has concluded that the use of high molecular weight phthalates in certain toys and childcare products poses no risk to infants. The findings, which also include adult sex toys, are in line with the conclusions presented last August by the European Chemicals Agency (ECHA).

Based on ECHA’s assessment, the Commission has concluded that “no unacceptable risk has been characterised for the uses of DINP and DIDP in articles other than toys and childcare articles which can be placed in the mouth”. The Commission further concluded that “in the light of the absence of any further risks from the uses of DINP and DIDP, the evaluation of potential substitutes has been less pertinent."......CLICK HERE to read more