Plastic products are found in almost every aspect of our every-day lives. From the automotive to packaging industries - plastic is everywhere. There are two types of plastics that are notorious for being difficult to bond to - Polypropylene (PP) and Polyethylene (PE or HDPE). These are the two famously "difficult substrates" in adhesive bonding applications everywhere. Here at Hotmelt.com, we have searched, tested and found the best adhesive available for providing a strong, permanent bond to low surface energy plastics like High Density Polyethylene and Polypropylene.
What are Polypropylene and Polyethylene?
Polypropylene - Also Know as PP
Polypropylene is a low surface energy plastic manufactured in very large volume and widely used in films, fibers and molded parts. It is often used for packaging as containers, absorbent pads and wrapping film as well as to create lightweight components for the automotive, appliance and medical industries.
Polyethylene - Also Known as PE, HDPE or LDPE
Polyethylene is the most common plastic, produced in the largest volume. It is often made into wrapping film for packaging and molded into bottles or other containers. Polyethylene has relatively low strength and low temperature resistance but is easy to process and used for applications where those factors are important.
Where are Polypropylene and Polyethylene Used?
Some of the most common uses of polypropylene and polyethylene are:
- Flexible and Rigid Packaging
- Fashion and Sports Industry (think tote bags and duffle bags)
- Medical Applications
- Consumer Products
- Automotive Industry
In summary, PP and PE are more sustainable plastic than their peers. It comes with plenty of structural, chemical, and physical advantages, costs very little to produce, and it is easy to find it in many aspects of everyday life.
Why are Polypropylene and Polyethylene So Difficult to Bond?
PP and PE are known for being difficult to bond due to its low surface energy. This characteristic has traditionally made it difficult for an adhesive to wet the surface and make a good bond. Instead, most adhesives tend to bead up on the surface, rather than penetrating it.
However, advances in adhesive chemistries and surface preparation techniques have made bonding to PE and PP more successful than ever.
MMA 500 - Permanent Bonds for Polypropylene & Polyethylene
Infinity Bond MMA 500 is a permanent solution for difficult to bond PE and PP substrates. MMA 500 is a very unique two-part adhesive that bonds difficult plastics like. Polyethylene (PE) and Polypropylene (PP) better than almost anything on the market. Infinity Bond MMA 500 is a 1:1 two-part adhesive that requires a cartridge gun and static mixer for dispensing.
Like most Methacrylate MMA adhesives, little to no surface prep is required before applying the MMA 500. It has a 4-5 minute open time and will create a permanent bond with chemical adhesion even to difficult plastics over the course of 24 hours.
Benefits of MMA Adhesives
MMA adhesives offer good chemical and environmental resistance , and fast cure speed. MMAs have higher peel strength and are more temperature resistant. They develop strength faster, allowing parts to be used sooner. Features of MMA adhesives include:
- High tension strength
- No primer needed
- Cure at room temperature
- Good flexibility at low temperatures
- Resistant to solvents and weathering
Testing for Success
Because PP and PE are so difficult we always recommend testing the adhesive with your substrate beforehand. Manufacturing can be different from product to product, success will depend on your substrates and what you are expecting from a bond. Testing the adhesive ahead of time will be the best solution to finding the best bond for your needs.
We Are Here to Help
If you are interested in the benefits that PP and PE offers in durability and chemical resistance and you are looking for the best method for bonding it, we have you covered. MMA 500 is hands-down the best product if you need something a little stronger. MMA 500 will provide a structural bond to even the toughest substrates. Contact us today with questions about your application or your next product. We look forward to changing the way you look at polypropylene.