I previously published an article about the different categories of TPE. This is that article with some updates including 1 additional material that I think should be classified as a TPE.Continue reading “The Complete Guide to TPE (updated)”
I received a request for a polypropylene the other day. The customer was looking for a grade that could be used for making “melt blown” fabric. I was not familiar with this process. You can see it in action in the above video. The polypropylene grades that are used for this have melt flows in the 1200-1500 g/10 minutes range (yes, you read that right).
The process uses an ordinary extrusion line but a high pressure gas is injected into the die which aerosol-izes the melted material and sprays it onto a roller.
I have been in this business for a while but this process was new to me.
Polycarbonate is a very versatile material that is used for all sorts of applications including many applications that require ultraviolet light resistance. Most grades are not suitable for these applications unless they are modified with a UV stabilizer additive. It is also important to ensure that you have the right UV additive for your application.
The picture above shows the pristine Pacific Ocean that used to exist before the ocean was destroyed by plastic waste. Hit the jump to see what the Pacific Ocean looks like now.
A common and frustrating problem with polypropylene materials and especially filled polypropylene materials is surface moisture on the pellets. Polypropylene is not hygroscopic so it does not absorb moisture out of the atmosphere but if the pellets have moisture on the surface, it will cause the same problems as you would experience running wet hygroscopic material like nylon. You will experience splay and loss of physical properties.
If you have not already seen price increases on nylon 66, you will soon. Nylon 66 is in tight supply and prices are increasing anywhere from $.10-$.50/lb depending on the grade.
There have been seven force-majeures declared on nylon 66 in 2018. The shortage is being caused by a shortage of adiponitrile (ADN) which is an ingredient used to make nylon 66.
Believe it or not, some of the reason for the shortage stems from Hurricane Harvey which hit the Texas gulf coast in August of last year. There are only 4 plants in the world that make ADN. Two of the plants are on the Texas gulf coast and they both went down before the hurricane hit. These plants don’t just turn back on with a switch, it takes a lot of time to get them started back up and up to full production.
The other factor is increasing demand for nylon 66. This is partly because of the improved US economy and partly because of light-weighting efforts being carried out by the auto industry which is causing a lot of parts that were previously make of metal to be switched to lighter engineering thermoplastics like nylon.
At some point, reduced supply and increased demand clash and unfortunately, we have passed that point.
It will likely take several years for more supply to come on line, in the meantime expect higher prices and longer lead times.
One option that some processors might explore is switching to nylon 6. Nylon 6 has reduced heat resistance but has higher impact and better surface appearance. Nylon 6 supplies are not great either but it is not as tight as 66. I have not seen any nylon 6 price increases this year as of yet. If a lot of people switch their nylon 66 applications to 6, we could see supply become very tight on 6 as well.
I have always known that the two-digit numbers in the Santoprene grades referred to the durometer hardness of the grades. For instance, Santoprene 101-55 is a 55 Shore A, 101-73 is a 73 Shore A, 101-87 is an 87 Shore A etc. Sometimes its good to verify the things that you know to be true.
Glass transition temperature is an often discussed but poorly understood property of plastic materials. I want to clear up some of the mystery of glass transition temperature and help you understand how it can be used in picking the right material for an application.
I know what you’re thinking. What does ironing have to do with glass transition temperature? Read on and find out.