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Sales and Market Development
A Review of Synthetic Lattices in Surgical Glove Use
The majority of commercial surgical gloves are still manufactured from natural rubber latex (NRL). However, NRL can lead to Type I allergic reactions, including risk of anaphylactic shock. In the race to reduce patient and medical staff allergy risks, a growing number of hospitals aim to eliminate products made from NRL, including surgical gloves. Drawbacks of NRL, including odor, and adverse allergic
(Type I) reactions, led to the development of synthetic alternatives. Examples of the alternative synthetic materials used today in surgical gloves include polychloroprene latex (CRL) and polyisoprene latex (IRL). However, replacement of NRL surgical gloves by synthetic alternatives has caused in the past some concerns regarding comfort and protection. Today, as high quality polyisoprene products made of Cariflex IR Latex are increasingly used in the health care world, such concerns are disappearing.
Cariflex™ Polyisoprene Products - The Clear Alternative
Manufacturers are faced with increasing consumer demands for the latest and most cost effective in rubber-based products: medical stoppers should be safe but convenient, shoe soles must combine comfort, long-life and fashion trends; protective gloves should be strong, but tactile and kind to skin. The pressure is on to find raw materials that can meet these challenges, and help keep customers’ products competitive. For applications where strength, comfort and protection are key, the demands placed on raw materials are particularly high. Cariflex IR, with its non-allergenic character, transparency, lack of odor, softness, hysteresis and good consistency, offers the ideal alternative to existing material solutions. Traditionally, natural rubber has been selected for use in a wide range of applications because of its key properties of durability, high tensile strength, tear resistance, ready availability and relatively low price.
Cariflex™ Isoprene Rubber (IR) for Medical Stoppers
There are two major synthetic polyisoprene types with high cis-1, 4 content. They include Ziegler-Natta IR, polymerized in the presence of a titanium/aluminum catalyst, and anionic IR, which is polymerized with an alkyl-lithium initiator. These different processes yield different products. Cariflex IR offers many features and benefits including protein-free, low residual metals, low gel content (~0 %), odor-free, and excellent coring properties (low risk of fragmentation). Cariflex IR is a highly clean rubber, which therefore can be used in medical stopper closures for glass and plastic infusion bottles, IV bags, and vials (where high gas barrier property is not essential).
Cariflex™ Polyisoprene Rubber
Cariflex polyisoprene rubber products (often abbreviated as Cariflex IR) are produced via anionic polymerization by Kraton Corporation in Belpre, Ohio. The anionic polymerization process results in linear polyisoprene chains with a narrow molecular weight distribution
and an extremely low gel content. The Cariflex polyisoprene grades are of the highest purity and are suitable for health care applications.
Cariflex IR products are supplied in 25-kg bales (55 pounds) wrapped in polyethylene film, and packed in a wooden crate of approximately 1 ton each.
Processing of Cariflex™ IR Polymers
Cariflex IR0307 polymer can be mixed using the following procedure. This procedure is based on processing in a 3.5 liter batch size 00C Banbury internal mixer. Adjustments may be required for mixing on a larger scale or if an intermeshing rotor type or mixer is used. The general principles will still apply. Please note that Cariflex IR0307 polymer cannot be employed in a single pass procedure. A certain amount of mastication of Cariflex IR307 polymer is required before powder addition can occur. If Cariflex IR0307 polymer is not masticated sufficiently before addition of powders poor mixing will occur and the batch will be dumped as a crumb and be very difficult to process.
Preparation of Synthetic Polyisoprene Latex
and its use in Coagulant Dipping
Natural rubber is one of the best known natural polymers. The material is derived from a milky suspension (latex), found in the sap of some plants. Mayans and Aztecs already harvested it from the hevea tree, and used it to make waterproof boots and balls. It is an elastomer: it recovers its original shape after stretching or deformation. Natural rubber is a polymer of isoprene (2-methyl-1,3-butadiene) with a molecular weight of 100,000 to 1,000,000. Most often the isoprene consists almost completely of cis-1,4-IR (~99%). This high cis content gives rise to strain hardening. The long, entangled chains are considerably branched1. Initially, natural rubber contains 5-10% of low gel. Upon storage the gel content increases and may reach values of 50%. Normally, natural rubber is treated to crosslink it.