Navigating the World of Medical Grade Plastics: Types, Advantages, and Applications in Healthcare

Medical grade plastics are essential in the production of medical products such as MRI casings, plastic syringes, and prosthetics. These plastics have biocompatibility, making them suitable for medical devices that come into contact with the human circulation system. Additionally, they possess properties like malleability, hardness, precision, and compatibility with injection molding and 3D printing processes.

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Each medical-grade plastic on the market has unique inherent properties similar to conventional plastic polymers. However, one key difference lies in biocompatibility since conventional plastic polymers do not take this factor into account. Selecting the appropriate medical-grade plastic for your product can be challenging, but we are here to help. In this article, we will introduce various types of medical plastics along with their advantages and provide you with a list of options for your project.

Are Medical Grade Plastics Safe?

Yes, medical-grade plastics are safe for producing medical components. The primary goal of medical products is to prevent and treat diseases and inhibit the growth of disease-causing organisms.

Safety is ensured through several properties including non-permeability, chemical/heat resistance, hardness, and most importantly, biocompatibility. By being non-permeable, these plastic polymers do not support the growth of disease-causing organisms. They can also be sterilized due to their chemical and heat resistance. Consequently, medical-grade polymers are suitable for creating products used in transporting bio-hazardous materials that could potentially spread dangerous infections.

Why Choose Polymers for Medical Applications

Several materials are utilized by medical component manufacturers to create parts for their products. Amongst these materials, plastics are increasingly becoming the top choice. Here are a few reasons why many manufacturers prefer plastic polymers over metals:

Inherent Properties: Plastic polymers offer durability, strength, chemical resistance, and heat resistance. This makes them suitable for medical components that undergo frequent sterilization. Some plastic polymers even exhibit hardness and tensile strength comparable to metals. For example, nylon has a high tensile strength of 12400 psi. Additionally, plastics are more cost-effective and are gradually replacing metals in the production of medical device components.

Excellent Manufacturing Property: Plastic polymers have high machinability and compatibility with various manufacturing processes. Depending on the desired outcome, common manufacturing processes include injection molding or 3D printing, blow molding, and sometimes CNC machining. Plastics allow for mass production without sacrificing accuracy and precision.

Recyclable: Thermoplastics, which are a type of plastic, can be recycled by melting and reshaping the plastic polymers repeatedly. This means that any unused parts during manufacturing can be reused, reducing material wastage and improving cost-effectiveness.

7 Types of Common Thermoplastics in Medical Injection Molding

Multiple medical-grade plastics find applications in different capacities within the medical industry. One of the most common types is thermoplastics, which refer to plastic polymers that soften when heated and harden upon cooling. Other types include thermosets, which become permanently solid after curing, and elastomers, which are viscoelastic (viscous and elastic) polymers capable of regaining their original shape and size after being stretched. However, thermoplastics are the primary focus here. Below are seven common thermoplastics used for medical parts:

Polyethylene: Polyethylene, also known as polythene, is a plastic polymer with a linear structure of monomeric ethylene formulated in high or low densities. Various types of polyethylene exist including high modulus polyethylene, high-density polyethylene, cross-linked polyethylene, and low-density polyethylene. These types possess general properties such as high mechanical strength, ductility, and melting points varying from 120°C to 180°C. Polyethylene is an excellent choice for medical grade plastic due to its cost-effectiveness, impact resistance, corrosion resistance, and solid structural integrity when subjected to frequent sterilization cycles. Its biologically inert and non-degradable nature makes it suitable for making prosthetics.

Polypropylene: Polypropylene is a white, rigid, and chemically resistant polymer produced through chain-growth polymerization of propylene and ethylene. This medical-grade polymer offers stress and cracking resistance, as well as impact and fatigue resistance. It has a high melting point at around 171°C, allowing it to withstand the heat generated in autoclaves. Consequently, polypropylene is applicable in manufacturing plastic components for medical devices such as disposable syringes, oxygenator membranes, prescription bottles, connectors, and finger-joint prostheses.

Polymethyl methacrylate (PMMA): Also known as acrylic glass, PMMA is a tough, durable, UV- light-resistant polymer produced from methyl methacrylate. It possesses exceptional light transmission properties along with coloring options. PMMA also exhibits high chemical resistance, making it an attractive option for many medical component manufacturers. With a melting point ranging from 200°C to 250°C, PMMA is compatible with blow molding or extrusion processes. This medical-grade product finds applications in creating endoscopic medical parts.

Polyvinyl chloride (PVC): PVC is a versatile medical polymer that comes in two general forms - flexible and rigid PVC. Flexible PVC is dense, inexpensive, and readily available. It is commonly used in areas where sterility is of utmost importance. On the other hand, rigid PVC is durable, strong, and hard. Both types of PVCs are suitable for manufacturing devices like hemodialysis tubing, cardiac catheters, and artificial limb materials. PVC is flame-resistant, chemical-resistant, and made by chlorinating PVC polymers.

Polyamide: Polyamide, better known as nylon, is a natural and synthetic polymer formed by linking the amino group of one molecule to the carboxylic group of another. Nylon is distinguished by its tensile strength, high abrasion resistance, chemical resistance, anti-corrosive properties, and flexibility. It can be manufactured through CNC machining, injection molding, and 3D printing. Properties such as tensile strength can be further improved by combining nylon with other materials. Stent delivery systems and prescription bottles are examples of polyamide medical parts.

Acrylonitrile butadiene styrene (ABS): ABS is a medical-grade plastic made by polymerizing styrene and acrylonitrile in the presence of polybutadiene. This polymer exhibits tensile strength, high abrasion resistance, chemical resistance, and anti-corrosive properties. It is compatible with several manufacturing processes including injection molding, blow molding, and extrusion. ABS is highly rigid and can replace metals under certain conditions. The medical industry utilizes it for making products like non-absorbable sutures and tracheal tubes.

Polycarbonate: Polycarbonate is a strong polymer produced by condensing bisphenol A and phosgene. It offers high transparency, toughness, flame retardancy, shatterproof properties, and abrasion resistance. Due to these qualities, polycarbonate serves as an excellent alternative to glass and can be sterilized using steam at 120°C, gamma radiation, or chemicals. The medical industry favors polycarbonate due to its high strength, good heat resistance, and biocompatibility. It finds applications in manufacturing medical components such as IV connectors used in renal dialysis and cardiac surgery.

Advantages of Medical Grade Plastics in the Healthcare Industry 

Apart from their inherent properties, medical grade plastics offer numerous advantages in the healthcare industry:

Versatility: Medical plastic polymers possess excellent moldability, allowing for various shapes and forms. This versatility enables innovation and versatile use in medical technology. Due to their flexibility, medical polymers are suitable for producing a wide range of medical parts including bedpans, inhalation masks, IV tubes, and catheters.

Easy Sterilization: Sterilization is a crucial aspect considered by many medical component manufacturers during production. Most medical-grade plastics can be sterilized, either chemically or through heat, depending on their resistance properties. Additionally, they have low costs, making them ideal for creating products intended for one-time use.

Infection Resistance: Plastic materials, like microplastics, have been developed to reduce bacteria growth by 99%. These specially modified plastic surfaces possess antimicrobial properties that repel or kill any bacteria that comes into contact with them. Such plastics eliminate the need for regular sterilization while remaining highly infection-resistant. They lower sterilization costs, prevent cross-contamination, and accelerate new medicine research.

Cost-Effectiveness: Using plastic to manufacture medical components proves cost-effective. The material cost is considerably lower compared to other options, and the manufacturing process is economical due to large-scale production capabilities. Despite lower costs, these plastics retain corrosion resistance, shatterproof attributes, biocompatibility, and the ability to withstand repeated sterilizations. Hence, the healthcare industry can reduce manufacturing costs while patients can benefit from lowered healthcare expenses.

Environmentally Friendly: Most medical thermoplastics are recyclable. For instance, polypropylene can be shaped repeatedly through heating while maintaining its properties. During the manufacturing process, any remnants or unused plastic polymers can be reused. This contrasts with other materials such as glass and metals, which require proper disposal methods. Consequently, the manufacturing process becomes more cost-effective.

Scope of Innovation: With emerging manufacturing techniques like 3D printing, medical manufacturers can explore new avenues for innovation at lower costs. For example, plastic prosthetics and implants are now replacing latex ones within the health industry.

Conclusion

Medical-grade plastics play a crucial role in creating products such as plastic gloves, plastic syringes, and surgical tools. Unlike conventional plastic polymers, they must possess biocompatibility. This article introduced a list of medical-grade plastics along with their types and advantages to help you select the right plastic material for your medical product. If you have any questions regarding the types of plastics used in medical devices, feel free to reach out to us.

FAQs

Q1: Do all medical-grade plastics have USP Class VI approval?

Not all medical-grade plastics have USP Class VI approval since there isn't a standard definition for what constitutes a medical grade. As a result, medical-grade polymers exhibit varying performance and quality levels. The USP Class VI approval or testing requires materials to demonstrate low toxicity levels. To ensure compliance, it is essential to consult an expert team knowledgeable about the requirements. For further details, contact .

Q2: What is ISO 10993 certification?

ISO 10993 certification verifies the biocompatibility of medical devices. The best medical device plastics should have high biocompatibility, indicating compatibility with the human body. Evaluation for ISO 10993 certification extends beyond medical-grade plastic polymers to include other materials such as additives, packaging, and degradation products.