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 NEWS - 2014


Gamma rays and thermoplastics

Gamma rays and thermoplastics: the frontier for medical, pharmaceutical, and food applications

Polymers used to manufacture medical devices and packaging may be sensitive to hydrolysis caused by autoclaving. Temperatures exceeding 120°C and pressurized steam may impair product functionality causing material deformation, distortion, breaking or softening. On the other hand, sterilization by gamma rays (gamma irradiation) is effective and does not cause significant temperature increases. Besides, it also allows the sterilization of materials already contained in the final package with even complex structures. Of course, materials require behavioral tests to check their compatibility with gamma rays.

To respond to the new market requirements, Lati and Gammarad Italia have started a collaboration aimed at testing irradiation on innovative plastics.

It was decided to test some materials intended for contact with food, as they are also widely used in biomedical and pharmaceutical applications.

As prescribed by regulations, any object coming into contact with human body, skin or mucous membranes for surgical activity as well as diagnosis and therapy, has to be sterilized.

Food and cosmetic industries are involved in the aseptic packaging of products without preservatives and unpasteurized.

  • diagnostic medical devices for in vitro analysis
  • laboratory equipment
  • medical devices and disposable products for dialysis, extracorporeal circulation (syringes, separation devices and collection tubes), respiratory devices.

packaging and pharmaceutical products for human and veterinary use.

food packaging in aseptic environment, caps and containers.

Thanks to its know-how, LATI has chosen state-of-the-art thermoplastic compounds that have proven resistant to gamma irradiation while maintaining technical, aesthetic, and certification features required by the application.

  • SULFONATES - Lasulf (PSU) / Lapex R (PPSU)
    The most versatile family of transparent amorphous resins normally selected for no-compromise applications in the medical and food field thanks to their outstanding temperature resistance. PPSU also features high impact resistance and chemical inertia, thus allowing the use even in applications normally precluded to other amorphous polymers.
    A finally satisfactory proposal in the field of plant-based polymers, renewable and sustainable. PLA is a valid transparent, moderate-cost material best suited to enhancing innovative disposable projects with a strong "green" image, without giving up the most varied pigmentations and additives supporting commercialization.
    Among high performance resins, PPS is undoubtedly the best price/performance compromise. This chemically inert material features excellent resistance to high temperatures and ensures the manufacture of parts with excellent dimensional stability and mechanical properties. Easy to mould, this polymer is today the most easily to process according to specific project requirements.
  • POLYAMIDE Latamid/Latigloss 66 (PA66) - Latene HT (COC) - COMMODITIES
    For the manufacture of large run products, polyolefin resins and polyamides are among the most versatile candidates ever for the development of variously reinforced and filled compounds. Ease of conversion and moderate price are well-known by sector technicians, who take advantage of these material properties for the most various projects in a wide range of industrial sectors, from mechanics to household appliances, from automotive to railway, and from medical applications to telecommunications.
Some families of thermoplastics manufactured by LATI were tested under three different irradiation doses: respectively 30, 60 and 150 kGy. Then, the variation of the following properties was evaluated:
  • mechanical,
  • thermal,
  • color, odor, and dimensional stability.

The 30 kGy dose is normally used for sterilization of medical devices, pharmaceuticals and packaging. The European Pharmacopoeia (Ph.EUR. paragraph 5.1) provides for sterilization by ionizing radiations with a minimum dose of 25 kGy.
The 60 kGy dose is used both in irradiation chemistry (modification of material properties, cross link) and sterilizing and antiviral treatments.
The 150 kGy dose is only used in irradiation chemistry (modification of material properties).


Mechanical decay (impact resistance, tensile modulus, tensile strength and elongation at break) as well as thermal decay (HDT and Vicat) were tested. Except for Latigea B01 (PLA) at extremely high levels of irradiation, the materials showed no significant changes.
One of the most important parameters that best quantify the degree of mechanical decay of the material as a result of irradiation is the percentage tensile elongation at break: a reduction clearly shows a breaking of the molecular chains resulting in weakening. None of the tested materials showed a reduction in elongation at break at 30 kGy. Sometimes, this value even showed a slight increase due to uncontrollable effects (moisture absorption, experimental error, etc.) or any secondary phenomena (partial cross-linking) certainly worthy of further investigation.

Yellowing, darkening, and change of the degree of transparency depend on the intrinsic chemistry of the material. This parameter is important as during medical procedures, operators must be able to quickly identify the device by color. Lapex R, Latigea, and Larton show no significant color changes.

All materials remain dimensionally stable.

No material shows odor change.

Lapex R
and Larton are the materials that do not undergo any mechanical, thermal or chromatic change when exposed to three doses of irradiation.
Partly due to its origin from renewable sources, Latigea shows good resistance to the treatment up to 30 kGy. This is an important feature for the use of this new family of materials in sterile applications where autoclave cannot be considered.

Most of the products tested, however, show no substantial changes in technical properties, but specially the color shows to be affected by the treatment.

Founded in 1945, LATI has always been a pioneering and leading company at European level in the field of thermoplastic compounds for injection molding intended for special applications.

LATI is focusing for a long time on compounds based on the most advanced base polymers for the manufacture of materials to be optimized for specific project and customer requirements.
From self-extinguishing to self-lubricating, from mechanical to thermal and chemical resistance, from thermal to electric conductivity: all the main properties of plastic materials are designed and managed by LATI in its compounds.

Materials engineered in this way are supplied to the most diverse industry sectors, thus making LATI not only a reliable and experienced supplier of high technology compounds, but also a development partner for professionals operating in the electrical and electronic field as well as automotive and transportation, telecommunications, mechanics, robotics, contact with food and drinking water and, of course, the medical sector.

Today, LATI products are distributed worldwide through a widespread commercial presence, with a strategically positioned logistic service also in all the emerging markets.

Founded in 1969 in Minerbio (Bologna), thanks to the intuition of a group of entrepreneurs attentive to technological evolution, Gammarad Italia is today one of the most complete and versatile European irradiation centers for the sterilization of outsourced products.

The Bolognese company's core business is the use of gamma rays, high-energy electromagnetic waves that, crossing the matter, destroy the bacterial and microbial charge without leaving any residue or causing alterations. Gamma radiation is a "cold process" and the temperature of the products treated does not increase significantly, ensuring a higher safety than all other methods of microbiological sterilization and decontamination.

Gammarad Italia’s strength is to invest an important part of its turnover, about 3 percent, for R&D activities, and to constantly carry out scientific activity at the side of the most prestigious national and international research bodies and institutes, such as the University of Bologna. Gammarad Italia has 9,000 Sqm warehouses on an area of 40,000 Sqm, in order to manage the storage and shipment of products both in Italy and abroad.

Gammarad Italia deals not only with sterilization, but also with:

  • the design and validation of the sterilization process;
  • the validation of sterile barrier system for medical devices, according to customer requirements, through accelerated aging and ongoing studies;
  • consulting services on issues related to the choice of new packaging and materials.
Gammarad Italia boasts a fully computerized integrated management of corporate warehouses that, in addition to contributing to the development of a state-of-the-art service, ensures maximum data accuracy and security.

8 July 2014
email: marketing@it.lati.com
LATI Industria Termoplastici S.p.A.
Via F. Baracca, 7 21040
Vedano Olona (VA) - Italy
Tel. : +390332409111 - Fax: +390332409307

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