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Studies say that latex-based products like gloves, medical devices and balloons can result in users falling ill. Find out why and what advances have been made to prevent this, in this report by Angelica Buan.
The milky sap derived from the rubber tree (Hevea brasiliensis), latex, is about 30-40% rubber and the rest is made up of resins, ash, sugar, water, and more than 200 types of proteins. Of this number, 13 are known to be allergens according to the American Latex Allergy Association (ALAA).
In the US healthcare environment, allergy from latex is comparatively low at 1% of the general population of about 3 million, states ALAA. Risk groups are further categorised as healthcare workers (8-17%), who are frequently using latex gloves or products, and individuals who have had multiple surgeries or children who have spina bifda-related surgeries (68%), all of which can be mitigated through avoidance of exposure.
Solving the dilemma with low-protein latex
For a long time, allergic reactions to latex proteins resulted in decreasing use of latex-based products. This is especially in the healthcare environment where latex gloves are important barrier devices and allergic reactions are major concerns.
Last year, the US Food and Drug Administration (FDA) issued guidance on latex product labelling. The agency had been equivocal with latex-free labels in products, for lack of existing tests that could determine the total absence of allergy-inducing proteins in natural rubber latex, and thus latex-free claims were misleading.
The FDA said that aside from medical gloves, a wide range of latexbased products, from adhesive bandages and catheters to sanitary napkins and blood pressure monitoring cuffs, can potentially trigger allergies and may cause anaphylactic shock. Any user may be at risk, it added. To minimise the risk, the agency suggested using powderfree gloves with reduced protein content.
Making latex products safer, a new technology product is offered. The Ultra Low Protein Lattices (ULPL) is developed by US-based Vystar Corporation, the exclusive creator of Vytex natural rubber latex (NRL), a raw material that features significantly reduced levels of the proteins inherent to NR latex.
Recently, a presentation was delivered by Dr Ranjit K. Matthan, an internationally renowned latex and rubber expert, who has joined Vystar’s Board of Directors and as Research & Development Director. Dr Matthan has been a consultant to Vystar since 2008 and has played a significant role in the manufacturing scale up of reduced-protein Vytex in Malaysia and refining the R&D of manufacturing processes for applications using Vytex NRL, such as latex foam, condoms, adhesives, medical devices.
In the session titled “Advances in Environmentally Friendly Ultra Low Protein Natural Rubber Specialty Latices” during the International Latex Conference 2015 held in August in Akron, Ohio, Dr Matthan revealed ongoing developments in the formulation of ULPL with reduced or no ammonia and nitrosamines. He said that these advances in aluminium hydroxide-treated ULPL properties and applications address concerns on volatile organic content and nitrosamines for some critical latex products, such as balloons, catheters, condoms, and other medical devices.
In formulating ULPL, Dr Matthan has pooled his expertise along with Joseph John, Director of the Polymer Consultancy Services in Chennai, India; and Bill Doyle, CEO of Vystar. The main man in ULPL’s R&D, Dr Matthan has been an important figure in South Asia’s rubber industry since the 1970s. He is also a key proponent for NR sustainability via the Bangkokbased Asia Pacific Elastomer Science and Technology (APEST).
Safety in the production chain – use of chemicals
Apart from allergy reactions, the chemicals required in processing latex also raise safety concerns. During processing, latex is preserved by anticoagulants like ammonia or sodium sulphite to prevent deterioration. The kind of anticoagulant used is dependent upon the production process. Sodium sulphite is preferred if crepe or sheet rubbers are to be made, but ammonia is more suitable for latex concentrate.
Latex-dipped products, such as balloons, gloves and condoms, contain the colourless, corrosive chemical ammonia. As explained in a study published by the Wisconsin-headquartered World Allergy Organisation, about 12% of harvested latex is treated either with 0.7% ammonia (high ammoniated latex) or with 0.2% of ammonia and thiuram combination (low ammoniated latex).
On a broad manufacturing set-up, workers in this segment also face risks in chemical exposure. The National Institute for Occupational Safety and Health (NIOSH) has released a hazard report for workers handling rubber products. The latter would refer to vehicle tyres, automotive and appliance mouldings, rubber bands, rubber gloves, and other barrier devices. Because making these rubber products involves application of heat, pressure and catalytic action onto the chemical mixtures, with dust, gases, vapours, fumes, and chemical by-products (e.g. nitrosamines) that occur from the manufacturing processes may contaminate the work areas. Thus, workers may be exposed to these hazards through inhalation and skin absorption.
The International Agency for Research on Cancer (IARC) of the World Health Organisation (WHO) came up with a study on exposure to rubber processing chemicals and found that workers in the rubber manufacturing industry are primarily vulnerable to dust and fumes from processing rubber and vulcanisation. The chemicals identified for potential exposure include nitrosamines, polycyclic aromatic hydrocarbons, solvents, and phthalates. “Inhalation is the main route of exposure, although workers may have dermal exposure as well, such as from cyclohexane-soluble compounds,” IARC said.
Barring chemicals, Vystar’s aluminium hydroxide-treated ULPL is formulated with reduced or no ammonia and nitrosamines, two of the chemicals that are found to cause health risks on exposure.
“In recent years, the latex industry has sought to reduce or eliminate the need for nitrosamines and ammonia in natural rubber latex to remove any potential health hazards for those with long term exposure in the production and in the manufacture of products in several end use applications,” stated Dr Matthan in a press release of the company. This development enables broader range applications minus the threat from leachable extractables – a rubber industry pipeline dream come true.
Balloons: party friends or environmental foes?
As harmless as it may seem but those party balloons that breathe life to a festivity can also pose safety risks. Claims of health risks associated with the latex that make up these colourful balls of fun say that they are not only potential choking hazards, since they contain chemicals occurring naturally and during processing, but that human and environmental exposure to latex balloons can be devastating.
Latex per se that is used in novelty items like balloons, in sexual wellness products like condoms, and in healthcare products like gloves, poses no direct harm to the environment.
According to New Jersey-headquartered The Balloon Council (TBC), latex is 100% natural substance that degrades in sunlight and water. One sign that a balloon is starting to degrade is when oxidation occurs, or also called frosting, that is when the balloon’s colour starts to fade. Exposure to sunlight as well as to certain microorganisms hastens the process.
TBC implies that latex balloons may have no major impact to the environment. A balloon that is released into the air, which is “well-tied and has no structural flaws”, can potentially ascend to an altitude of about 5 miles where it freezes and is shred into pieces, TBC explained. The pieces that would drop to the ground (or into a body of water) can sometimes be ingested by land or sea animals, TBC said, adding that evidence showed rubber pieces that passed through the digestive tracts of animals have not harmed them. TBC also cited that latex balloons “biodegrade at about the same rate as a leaf from an oak tree.”
While the US organisation of retailers, manufacturers and distributors of balloons aver that balloons are not found to be a significant litter problem, based on beach clean-up observations, it strongly recommends proper waste disposal of the latex product.
The “biodegradable” claim for latex balloons is slammed by Balloons Blow, a non-profit organisation based in Florida, US, and which campaigns against balloons being released into the environment. It said that while NR latex may be biodegradable, the chemicals, plasticisers and artificial dyes added into the material shrivel latex’s biodegradability factor.
Moreover, likening latex’s biodegradability to an oak leaf is “misleading”, stated Balloons Blow on its website. It explained, “Oak leaves are very durable. They can take four years to decompose and that means balloons have plenty of time to injure or kill.”
It also added that the remaining shreds from a burst balloon could be mistaken by animals for food – a gaffe that could potentially block the digestive tract of the animal, leading to starvation or death, or both.
It said that sea turtles particularly are prone to this fatal ingestion. “They naturally prey on jelly fish, which balloons can easily be mistaken for, even with human eyes,” the environmental conservation group said. Balloons Blow seeks to raise awareness about pollution from balloons, which it said is a “growing problem and one that needs to be addressed.”
Vystar makes a case for its NRL
Meanwhile, Vystar’s Vytex NRL has been used by Pioneer Balloon Company, the largest US producer of balloons. It has upgraded to using treated NRL for use in the high-end, jewel-tone colour balloons.
It adds, “Treated NRL produces a very high quality, more translucent balloon that has better barrier properties than ordinary NRL. No doubt this is due to removal of the lutoids and Frey-Wyssling particles to reduce discolouring by removing the opportunity of PPO browning, higher rubber to nonrubber ratio, and reduction of odourous low molecular weight acids.” Vytex NRL is biodegradable, stated Vystar. “The latex grade, when used in balloons, can return to nature in as little as six months,” says the US firm.
Vystar also says that several adhesive and foam manufacturers have also upgraded to the use of treated NRL, including Islatex, which launched high-end foam pillows made from aluminium hydroxide-treated latex. The company says it continues to work with manufacturers across a broad range of consumer and medical products, such as Tamicare and their Cosyflex product.
Vystar adds, “Glove manufacturers continue to differentiate their products and upgrade to Vytex due to the softness/low modulus and are able to increase filler loading due to the absence of non-rubbers, reduce leaching processes and cost.”
Other benefits of Vytex are that the aluminium hydroxide-treated NRL has a longer “pot life”, compared to regular NRL, which benefits glove manufacturers in terms of longer shelf life of the compound allowing for more dipping flexibility.
“These attributes are attractive in other applications, such as foam, where less rubber odour and a whiter colour are highly desirable. Aluminium hydroxide treated- NRL has a low non-rubber content compared to regular NRL and is virtually free of the 14kD and 30kD polypeptide proteins reported to be known Type 1 latex allergens. These characteristics make it the material of choice for applications seeking high-quality, safer end products,” says Dr Matthan in his presentation.
Additionally, Vytex NRL contains no known or suspected human carcinogens, said Dr Matthan, concluding that the 100% renewable resource latex grade provides a “safer and healthier environment for consumers, workers and the planet.”