Medical / Pharma
Thermal Sensitivity Problems? Stratek's Tek-MixTM Offers a Valuable Solution
One of the serious problems encountered by medical compounders is the thermal sensitivity of the materials they are mixing. The temperatures required for processing most "host" or "matrix" materials often exceed the threshold temperatures at which themal degradation begins in these fragile additives. An interesting article in Plastics Additives and Compounding Magazine, titled "Preventing Bacterial Growth: Plastics Additives & Compounding" introduces this problem and covers many additive materials new to the market which display less thermal sensitivity.
The article states that "Many chemicals have antimicrobial properties, but few are suitable for use in plastics, requiring low cost, compatibility, thermal stability during processing, environmental stability, and safe and easy handling." In fact, as the excerpt below shows, manufacturers of antimicrobial additives are making concentrated attempts to increase the thermal threshold at which their materials begin to decay. Considering that Tek-MixTM processing regularly decreases operating temperature by 50oC or more, the survivability of these antimicrobial additives would be greatly enhanced with Tek-MixTM processing.
Included in this article is a listing of antimicrobial products such as:
- Ferro Corporation: Micro-Chek® antimicrobials from Ferro Corporation are claimed to prevent premature product failure by inhibiting micro-organisms that stain and degrade polymeric materials. Micro-Chek is formulated effectively to provide protection in the most stressful of outdoor environments like roofing membranes, awnings and automotive trim. The company adds that Micro-Chek also provides superior performance in less severe applications such as wall coverings and appliance gasketing.
- Thor Group: The company is primarily a manufacturer of biocides based on isothiazolinones, however, the company also produces an extensive range of standard and customized biocides containing other active ingredients such as aldehydes, triazines and quaternary ammonium compounds. Acticide® biocides prevent the biodeterioration of products both in their wet/fluid, dry/cured and intermediate states.
| A Word About Silver-based Antimicrobials: Silver antimicrobial additives are also widely used in plastics. The inert nature and antimicrobial efficiency of silver make it an attractive option for the food processing and medical equipment industries. It is not toxic, flammable or corrosive and will not cause bacteria to become resistant to antibiotics. Silver-based antimicrobials work through an ion exchange mechanism that slowly releases silver ions, which interact with the bonding sites on the microbe surface to prevent bacteria from reproducing. |
- Ciba Specialty Chemicals: Ciba offers a number of products for antimicrobial applications. The company has submitted a master file to the Center for Devices and Radiological Health of the US Food and Drug Administration (FDA) for its HyGentic™ 4000 silver-based antimicrobial for medical device applications. The master file can be immediately cross-referenced by marketers and developers of devices containing the novel, silver-based technology to support regulatory approvals. The comprehensive data set contained in the master file includes anticipated device applications, chemistry, and toxicology data along with detailed descriptions of manufacturing, labelling, packaging, and distribution processes and practices and the associated quality controls that are in place. Ciba plans to submit additional master files for related products to the FDA in the future. HyGentic™ 4000, a form of elemental silver with unique physical properties was developed by Bio-Gate AG and is distributed globally by Ciba Specialty Chemicals. It is claimed to be particularly well suited for implanted or inserted medical devices where antimicrobial solutions are increasingly in demand. A similar antimicrobial technology developed by Bio-Gate designed for dental fillings is marketed in Europe.
- Ciba® Irgaguard® B 5000/B7000 series is a silver-based, inorganic antimicrobial range that inhibits the growth of micro-organisms such as bacteria, mould, mildew and fungus that can cause deterioration, unpleasant odour and discoloration on the surface of plastic materials and articles intended to come into contact with food. Ciba also offers HyGate™ for plastics and fibre applications. These are offered in two different product forms: HyGate™ 4000 and HyGate™ 9000 - the latter is particularly recommended for transparent polymers and microfibres. According to Ciba, HyGate™ is a good choice when the antimicrobial activity is expected to be highly durable. It can be incorporated into many polymers and man-made fibres. It works as an antimicrobial reservoir. In addition, HyGate™ exhibits its antimicrobial efficacy by preventing the colonization of organisms by being available at the surface of the item. HyGate™4000 is suitable for thermoplastic polymers, such as PA, PET, TPU and PVC. As well as the general advantages of HyGate, it also contributes to cost savings because polymers and fibres maintain their properties for a long time. HyGate 4000 also keeps its activity even when articles are exposed to harsh cleaning procedures or UV-light. HyGate™9000 is recommended for polymers and fibres, particularly when the articles need to remain transparent and when the diameter of fibres is extremely small.
- AgION Technologies: A recent example of silver-based antimicrobial protection is provided by AgION Technologies for the Logitech® Cordless Desktop® MX 3200 Laser, which is a wireless keyboard-and–mouse combination, against a broad spectrum of bacteria a. According to AgION, the silver-based antimicrobial in the Logitech Cordless Desktop MX 3200 Laser is effective in protecting the product against a broad spectrum of bacteria. The AgION antimicrobial incorporated into the Logitech Cordless Desktop MX 3200 Laser is comprised of naturally occurring silver ions. Silver has long been recognized for its antimicrobial properties and humans have used silver for thousands of years to combat a wide range of microbes. The AgION antimicrobial provides continuous and long-lasting protection from microbes by releasing silver ions to the surface of the keyboard and mouse at a slow and steady rate. This creates a self-cleaning surface that combats existing micro-organisms as well as any new ones that come along. The patented AgION antimicrobial technology is designed to last throughout the life of the products. AgION’s antimicrobial has been proven effective against a broad range of micro-organisms, including bacteria, algae, and fungi such as mould and yeast, yet is safe enough for human and food contact. AgION’s antimicrobial has been approved for food and water contact by the Environmental Protection Agency and is listed as an indirect food contact substance with the Food and Drug Administration.
- Sanitized AG: Sanitized® Silver is a new-type antimicrobial active ingredient with a broad range of action based on silver, a naturally occurring precious metal. With the use of a unique glass ceramic carrier, Sanitized AG says that it has succeeded in virtually doubling the efficiency yield of this product over other silver-based active ingredients while reducing the necessary application amount by one-half. According to the company, the result is safety, efficiency and high economy. The active ingredient is incorporated directly into the plastic material. The glass ceramic carrier activates the silver ions only when the surrounding conditions are favourable to the growth of microbes and the active ingredient, based on natural silver, is resistant even at high temperatures of over 350°C. In addition, the transparent glass ceramic carrier has minimal or no effect on the optical properties of clear plastics, unlike other known active ingredients also based on silver. The company adds that Sanitized Silver is exceptionally non-discolouring, and even in direct contact with foods, such as cheese, it causes no discolorations whatsoever. Sanitized Silver is approved by the US FDA.
- AddMaster: UK company AddMaster has developed Biomaster that can be supplied as masterbatches, compounds or powder dispersions. The company says that the high concentration of silver in the antimicrobial active agent in Biomaster provides a release of silver ions on demand, which in turn safely inhibits microbial growth. The products are said to exhibit excellent temperature stability (up to 600˚C) and are therefore suitable for incorporation into all thermoplastic and thermoset resin systems with no detrimental effects on the physical properties. Products are available for clear and opaque applications. The company says that Biomaster antibacterial additives are suitable for use in a wide range of processes such as injection moulding, profile and tube extrusion, synthetic fibres, blow moulding, blown films, extruded films and sheets, calendaring and rotational moulding. Biomaster products contain typically ten times more silver than other silver biocides, and consequently they only need to be used at very low concentrations. According to AddMaster, it has been demonstrated that plastic products incorporating Biomaster at very low addition levels actively inhibit bacterial growth and show a 99.99% reduction within 24 hours. The controlled release of the silver active ingredient provides maximum long term activity. Biomaster additives are powerful broad-spectrum, inorganic, silver-based biocides for use in the preparation of antibacterial plastics. AddMaster says that the Biomaster range has been successfully tested against over 50 common organisms such as MRSA, E.coli, Salmonella, Listeria, Pseudomonas and Aspergillus Niger. Applications include medical devices, moulded hospital equipment and healthcare furnishings, as well as soap and tissue dispensers, toilet seats and door handles. Biomaster is also suitable for electronic handsets, water filter housings and pharmaceutical packaging.
- Milliken Chemical: Miliken has invested in a new European Microbiology Laboratory, to expand its technical service offering to customers. The company says that this is a result of continued growth and market acceptance for the Alphasan® silver inorganic antimicrobial technology. Located at Milliken’s Technical Centre in Gent, Belgium, the company says that its European customers can now take advantage of faster, more efficient microbiology support. The Milliken Europe Microbiology Laboratory will provide in-house material and finished part testing facilities to customers active in the plastics, rubber and textile sectors, from compounders and masterbatch producers to OEMs, says the company. Traditionally, European testing activities have been outsourced, with internal support only available to customers using the Microbiology Laboratory at Milliken’s headquarters in South Carolina, USA. The facility offers standard microbiology equipment such as inoculation and colony counting facilities, sterilization autoclaves, safety cabinets, incubators and microscopy services. In addition to customer test facilities, the laboratory will support research and development activity relating to Milliken’s Alphasan silver inorganic antimicrobial technology.
- AlphaSan antimicrobial additive is a zirconium phosphate-based ceramic ion-exchange resin containing silver. According to Milliken, high temperature stability and low colour formation make AlphaSan suited to provide antimicrobial performance in a wide variety of applications including plastics. Silver is well known as being safe for human contact and effective against a broad spectrum of micro-organisms that cause odour, discoloration, biofouling and other aesthetic problems. These antimicrobial properties can bring additional value through product differentiation to a variety of applications. AlphaSan can be added to approved materials at varying levels to impart bacteriostatic, fungistatic, and algistatic properties to the material and the end-use article.
- Troy Corporation: Troy offers a number of different types of antimicrobial solutions for plastics under the brand name Micropel.
- Akcros Chemicals: Akcros has developed the Intercide range of products for PVC and are based on a choice of active biocides contained in a phthalate plasticizer, epoxy co-stabiliser or solid co-polymer. The Intercide ABF products are based on OBPA, while Intercide OBF and Intercide IBF products are arsenic-free alternatives. Intercide ABF-5-DIDP consists of a 5% solution of OBPA in DIDP. The company says that the more concentrated material means that less primary plasticizer is needed in a formulation. It is recommended for use at 0.6-1.0% by weight of the total PVC formulation to provide attack from a wide spectrum of fungi and bacteria
Tek-MixTM - Extensional / Elongational Flow Mixing
The Next Step in Mixing & Blending
The Next Step in Mixing & Blending
