Covestro, Lotte and other innovative solutions have frequently appeared in the outbreak of medical plastics. What are the commonly used medical plastics?

The global new crown virus pneumonia epidemic that began in early 2020 has entered its third year, but the haze has been difficult to disperse for a long time. Now in March and April of 2022, there is no spring blossom, but people are waiting for the bitter “cold spring”. The epidemic situation has changed abruptly. Hong Kong, Shenzhen, Jilin, Shanghai… There have been waves of domestic epidemics. The big counterattack, the situation is worrying, and affects the hearts of the people of the whole country.

During the more than two years of the virus pandemic, most plastic supply chains have remained open, and processors of medical anti-epidemic materials, manufacturers and suppliers of resin materials, equipment, and molds are all doing their part in this “battle” made a great contribution. They let us see test strips produced by thermoforming equipment and film extruders, vaccine syringes made by mold makers and injection molding manufacturers, forehead thermometers.

Affected by the epidemic, the demand for medical plastics such as PE, PP and PC by medical disposables, medical equipment and equipment manufacturers ushered in a period of explosive growth, and various medical plastics also exploded.

Eight commonly used medical plastics

There are about a dozen commonly used medical plastic materials, polyethylene (PE), polypropylene (PP), polyvinyl chloride (PVC), polyurethane (PU), polytetrafluoroethylene (PTFE), polycarbonate (PC) , polystyrene (PS), etc., PVC and PE are the largest, accounting for 28% and 24% respectively; PS accounts for 18%; PP accounts for 16%; engineering plastics account for 14%.

01. PVC

PVC is a low-cost amorphous plastic with excellent chemical resistance and antimicrobial resistance. According to market estimates, PVC accounts for 28% of the medical plastics market. The advantage is that the cost of PVC resin is low, the application range is wide, and it is extremely easy to process. The disadvantage is that PVC, as a polar material, has an adsorption effect on some drugs, and the plasticizer DEHP may be precipitated to harm the human body.

PVC products for medical applications include: blood bags, hemodialysis tubing, breathing masks, oxygen inhalation tubes, urine bags, artificial ears and noses, etc.

02. PE

PE is the general plastic with the largest output. It has the advantages of good processing performance, low cost, non-toxic and tasteless, and good biocompatibility. Ordinary PE can usually be used for medicine bottles, needle caps, syringe push rods, infusion set flow regulators, infusion sets and syringe packaging bags, etc.

UHMWPE (Ultra High Molecular Weight Polyethylene) is a special engineering plastic with high impact resistance, strong wear resistance (the crown of plastics), small friction coefficient, biological inertness and good energy absorption characteristics. Its chemical resistance is comparable to Comparable to PTFE; it is an ideal material for artificial hips and artificial joints.

03. PP

PP has excellent chemical resistance, fatigue resistance, good heat resistance, and can be sterilized at temperatures above 100 °C. Easy to process, no environmental stress cracking issues. Medical PP has higher transparency, better barrier properties and radiation resistance.

It can be used in infusion bags, disposable syringes, connectors, parenteral injection nutrition packaging, dialysis membranes, etc.

04. PS, K resin

The amount of PS in the medical field is second only to PVC and PE. Its texture is hard and brittle, and it has a high thermal expansion coefficient. Therefore, it limits its application in engineering. In recent decades, modified polystyrene and styrene-based copolymers have been developed to overcome the shortcomings of polystyrene to a certain extent. K resin is one of them.

K-resin is a block copolymer made of styrene and butadiene as monomers. Its main characteristics are high transparency and good impact resistance, low density, strong tinting strength, excellent processing performance and non-toxicity.

K resin is mainly used in medical plastic products with difficult processing technology, high technical content and high added value, such as the changing chamber of artificial lung-oxygenator, the outlet of arterial blood vessel, the outlet of arterial outlet of recovery device, the suction head of the heart, the aorta Intubation, blood filter, suction device, temperature changer, etc., and K resin meets the requirements of Class VI-50 of the US Drug Packaging Law.

05. ABS

ABS plastic is a terpolymer of three monomers, acrylonitrile (A), butadiene (B) and styrene (S). It has certain rigidity, hardness, impact resistance and chemical resistance, radiation resistance and ring resistance Oxyethane disinfection.

The medical application of ABS is mainly used as surgical tools, roller clips, plastic needles, tool boxes, diagnostic devices and hearing aid shells, especially the shells of some large medical equipment.

06. PC

The characteristics of PC are high toughness, strength and heat-resistant steam sterilization, which make PC the preferred choice for hemodialysis filters, surgical tool handles and oxygen tanks; PC applications in medicine also include needle-free injection systems, perfusion instruments, Blood Centrifuge Bowl and Pistons.

07. PTFE

PTFE is a type of fluoroplastic, known as the king of plastics, with the lowest known coefficient of friction and the best chemical resistance of all plastics. It has good biocompatibility and anticoagulation, does not decompose, has no adverse reactions in the implanted body, and has no obvious aging, and has excellent heat resistance. The continuous use temperature is 260 ° C, and high temperature disinfection can be used.

In the medical field, it is widely used in various artificial trachea, esophagus, bile duct, urethra, artificial peritoneum, brain dura, artificial skin, artificial bone, etc.

08. TPU

Thermoplastic Elastomer (TPU) has excellent low temperature flexibility and resistance to hydrolysis, blood coagulation, and anti-microbial attack, and can be used in medical catheters, artificial hearts, oxygen masks, drug delivery equipment, IV connectors, and rubber bladder bags for blood pressure monitors, wrapping cloth for topical administration, etc.

Medical plastic innovation 01 new crown detection kit in the fight against the epidemic
The rise of this product will naturally drive the growth of upstream material demand. A set of new crown test kit equipment contains a nasopharyngeal swab/oropharyngeal swab, a test cartridge, and an extraction tube for reagents.

The special plastic particles for detecting the jam are generally polystyrene (PS) or polyvinyl chloride (PVC). Good impact resistance can reduce the possibility of damage in different environments such as high and low temperature. High enough molding fluidity can provide higher injection molding. Processing efficiency and excellent laser engraving performance can produce packaging labels that take into account flexibility and clarity.

Nasopharyngeal swabs/oropharyngeal swabs use thermoplastic handles, and the extraction tubes of reagents are mostly injection molded from polyethylene (PE), because PE has excellent biosafety, chemical resistance, and more importantly. It has high barrier properties and high cost performance.

Kumho Sunli’s micro-innovation brand Suyouan™ has recently developed a special material for the shell of the new crown antigen detection box: HIPS N522. In addition to processing and transportation, as a product mainly based on online shopping channels, due to storage environment and logistics factors, it is more likely to cause defects such as cracks in the antigen detection box. N522 makes up for the weakness of traditional HIPS.

Compared with traditional HIPS, N522 has higher melting index, wider processing window and shorter molding cycle. When market demand surges, N522 can seize the market faster. Compared with conventional HIPS, N522 can clearly engrave in black and white, with efficient marking.

02. Conductive pipette tips

With the advancement of medical technology, in vitro diagnostics (IVD) are increasingly used in clinical practice. The continuous development of the new crown epidemic has accelerated the blowout of the IVD market, and the conductive pipette tip, one of the indispensable laboratory consumables in the diagnosis process, has also become a hot commodity in the market.

Usually made of plastic, pipette tips are long, thin, conical hollow plastic parts used with pipettes to measure and dispense liquids in laboratory and production environments. In automated systems, pipette tips are often made of conductive polymer materials, allowing the tips to sense liquids.

The market for conductive pipette tips is booming, but excellent materials are in short supply. It is formulated from a variety of base resins, including ABS, PP, LCP, PA, PC, PPS, and PEEK, to provide a unique combination and optimal balance of electrical conductivity, mechanical properties and processability for laboratory consumable production Manufacturers make conductive pipette tips with higher quality and faster time-to-market.

03. LDS syringe

As the global COVID-19 vaccination campaign is in full swing, the demand for syringes, from which medical-grade polypropylene (PP) is made, has exploded exponentially.

LOTTE Chemical, a major Korean chemical company, uses BASF’s Irgastab®, a non-discoloring plastic processing stabilizer, to produce medical PP. Lotte’s medical PP has been used to produce LDS (low dead space) syringes developed by a Korean medical syringe manufacturer. This special syringe is designed to minimise the amount of drug that remains in the needle after injection, thereby reducing vaccine waste. With the use of LDS syringes, the number of people vaccinated with the same vaccine dose can be increased by 20%, therefore, LDS syringes have a huge global demand.

04. Casing system

Cannula systems are liquid drug packages presented in the form of vials or prefilled syringes. Because vaccine vials are also available in this packaging, the Covid-19 pandemic has seen a surge in global demand for the product.

For Röchling Medical, Germany, the cannula system is a new application that places one requirement on injection molding production: flexibility.

The dimensions of the sleeve packs are standardized, and throughout filling and processing, the vaccine vials remain in the nest, so they do not tip over and bump into each other. In the honeycomb structure, the vials, usually made of glass, are well protected. Nest holds 16 vials of 50 ml doses. The smaller the fill volume, the higher the number of vials the package can hold, and the more honeycombs nested inserts.

For this highly demanding component geometry, a polyoxymethylene POM material is used, which can safely withstand cleaning prior to the filling process while being economical. However, due to its strong shrinkage, POM places high demands on the stability and repeatability of the injection molding process. The company currently produces nested inserts in five sizes using two all-electric e-motion large injection molding machines from ENGEL, with a clamping force of 5,000 kN, cycle times of up to 40 seconds, and 24/7 production at full capacity. The two large machines are part of a larger package from ENGEL to Röchling. A total of eight e-motion injection moulding machines with clamping forces of 1600, 2800 and 5000 kN are used to produce pipettes in addition to the casing system Anti-epidemic materials such as tips and microtiter plate holders.

05. Medical equipment to prevent virus spread

Ultraviolet light (UVC) has a powerful germicidal effect on bacteria and viruses, and UVC LED lamps are increasingly used for surface disinfection in medical settings. But sterilization affects some materials, so engineers and designers must choose materials that retain their physical and aesthetic properties even after repeated UVC sterilization.

As the COVID-19 pandemic spreads, the medical device industry is looking for new ways to sterilize products that can help prevent the spread of COVID-19 and other pathogens. Makrolon® polycarbonate PC and Bayblend® PC + ABS blends developed by Covestro can withstand frequent sterilization, and after UVC treatment, the physical properties of the material such as strength and heat resistance are fully retained. The white material turned yellow, while the black material was largely free of color casts and maintained a surface finish in all cases, allowing for frequent disinfection, driving the development of surface disinfection.

06. Medical goggles

Medical goggles can prevent the virus from entering the eyes and reduce the chance of infection for medical staff. Lubrizol has partnered with Nike to produce full protective face shields and PAPR masks to protect healthcare workers on the front lines of the fight against COVID-19.

Nike’s full face shield transforms elements of its own branded footwear and apparel, including thermoplastic polyurethane. Lubrizol’s innovation team quickly evaluated materials, made recommendations for performance optimization and rearranged production and supply chains to produce and donate ESTANE® thermoplastic polyurethane (TPU) polymer, the material needed for Nike.

ESTANE TPU is also used in the visors of Powered Dust Respirator (PAPR) helmets to protect against airborne pathogens. Combining the elasticity of rubber with the rigidity of plastic, ESTANE TPU can also be used in medical protective clothing, medical equipment, medical mattresses, rigid tubes, hoses, medical devices and many other critical products.