Can PVC or Vinyl be recycled?
PVC can be recycled. We have been recycling uPVC at MGM Industries each and every day since we started extruding the material in 1999. We started making PVC (vinyl) windows in 1985, and we purchased our material until 1999. From 1985 until 1999, we were indoctrinated into the thought that recycled PVC was “bad PVC”. For for 14 years we, too, were told repeatedly that the only good PVC was virgin PVC. We were told by people in the industry that “blue-white” PVC is regrind material 1 . This is an old wives-tale within the window industry that is absolutely false.
The point is there is a lot of inaccurate information that is put out there for the public’s perusal. The purpose of this article is to try to give you some solid information for you to consider. And then you can make up your own mind. Before you read further it is suggested you read “What is PVC made of?”–you have to know what is in the material before you can assess whether or not it is recyclable.
There is nothing in PVC that is degradable by re-extruding pre-process material except the internal and external waxes that are placed in the compound in order to process it. The above referenced article explains these ingredients. These ingredients are diminished on each extrusion cycle. However, the Chemical Engineers that design uPVC know this and they put in enough of the internal and external waxes into the compound so that the material can go through a multiple cycles of extrusion/recycling–extrusion/recycling. Compound suppliers have dialed in the formulation for over 30 years–and have designed uPVC compound to be recycled multiple times. The reason for doing this had nothing to do about saving the environment–it had to do about keeping the extruders in business. Extruding PVC (vinyl) into window profiles is very difficult because the product requires tolerances in the thousanths of an inch. As a result there has always been “scrap” inherent in the business. A good extruder will have “scrap” in the 10% range, a bad extruder will have “scrap” far exceeding 10%. Extrusion companies have always had to reuse that “scrap”, lest go out of business. It’s really not scrap. A better way to describe it is as pre-processed material.
In the past, extrusion companies–for some reason or the other–have always kept that fact that they use pre-processed material a secret. In truth, when PVC is run a second time, you can argue that the finished goods are better than that which you get from running virgin material. Why? When PVC is blended with all the other ingredients, the compound (dryblend) is actually blended in a high speed mixer to around 210oF then dropped into a cooler unit which drops the dryblend temp to around 140oF2. At this temperature the material is dropped from the cooler, considered blended and packaged for delivery. It’s analogous to a bread dough. The more you knead it, the more homogenized the dough gets. The more you knead the PVC dough the more the impact modifiers (typically acrylic plastics) and other ingredients get interspersed in to the mix. Actually you can think of window grade PVC as an alloy of PVC, Acrylic plastics, TiO2, etc…the more you mix it the greater the bond between the amalgamation of materials.
I think you can imagine, sometimes it does not get fully blended by the compounder (perhaps they don’t blend it long enough at the raised temperature, or perhaps they lower the max temperature just a tad.) For what ever reason, there are times when the material does not fully “fuse” in the barrel of the extruder. In essence, the extruder barrel does not have time to do the final mixing of the material. If it is not fused or mixed sufficiently in the barrel, then the end result will be brittle material. The magic solution to a brittle finished part: grind it up and extrude it again. Each time you run the material in an extruder, you will blend the material a little more. There is a point at which further blending is unnecessary, but it certainly is not going to “degrade” the PVC molecule by further processing3. The other ingredients also do not degrade. Titanium Dioxide (TiO2) is a mineral that gives the PVC it’s resistance against the Ultra-violet (UV) rays of the Sun. Window compound has to have at least 9 parts per 100 of TiO2 in order to effectively keep the UV rays from degrading the PVC. TiO2 is literally a rock mined from the earth. It will NOT degrade in the Sun and it will NOT degrade by re-extruding the PVC. It is the primary ingredient in PVC to make PVC exterior weatherable.
Prudently selected recycled PVC can create a better product. We do it every day. The key is managing the source of the PVC and then managing the sorting process. It has to be cleaned of foreign debris such as silicone, woolpile, odd colors–such as black flex material. At MGM we have become experts in recycling vinyl, and we are proud of it. (For our application, the collected recyclate has to have at least 9/100 of TiO2 in the compound, so we only recycle window and door grade PVC) 4.
That’s why we can honestly say that using a blend of 20% regrind and 80% virgin can produce a better product then running 100% virgin. Actually one can reasonably argue that windows made out of 100% regrind is better than windows made out of 100% virgin material. I can go on and on about this subject, but I think I’ve bore you enough. The bottom line is that PVC can be recycled and should be recycled. We live in a complex world which is ever growing in population. As a society and as a people, we have to make good environmentally sound decisions if we want to protect our earth. I think it is socially responsible to provide uPVC (vinyl) windows because they are so energy efficient, and, at the same time, we can be environmentally sensitive to our planets needs by recycling as much uPVC material as possible. At MGM we recycle more uPVC than we produce internally within our company. It is possible to recycle uPVC and we do it. If you want to know more, just give me a call, I’m Abe and I love PVC, I think it is a great material. To learn more about MGM Industries vinyl windows and doors go to our website.
Comments from Abe Gaskins:
1The truth is that blue-white material has blue pigment in it. I don’t for the life of me know why years ago the fenestration industry standardized on blue-white material. Some years ago the standard changed to “euro-white”, which is none other than the natural color of the PVC compound blended formula without any pigments. It was just a me-too type of thing: somebody introduced a blue-white window and the copy-cat market eventually standardized on it, until market pricing forced the blue-white pigment out of the compound.
2A very good friend/compound engineer corrected me a bit. Originally, I stated the dryblend was dropped at 140o and did not mention the maximum 210oF. He brought my error to my attention and I learned something about the details of compounding that I did not previously know. The point is, when I am in error, I would appreciate it if I am corrected. I enjoy learning and I want my blog to be interesting and factually correct.
3Actually, you can keep recycling the material until enough of the internal and external waxes are deminished to the point at which the surface finish will look like an orange peel. At this point the material is sticking to the exit plates of the extrusion die, the screw and the barrel of the extruder. The test lab located at the compounder can process the material until it yellows. In practice, the extrusion company will not see the yellowing because the surface finish will be the first thing to be unacceptable. If yellowing occurs I think it is reasonable to say that the PVC molecule is degrading. In my tenure at MGM, I have not seen any yellowing of recycled PVC. Therefore I make the statement that reprocessing uPVC by the extruder will not breakdown the PVC molecule. The PVC extrudate leaves the “hot die” at about 360oF. At this temperature the PVC will not burn because it does not stay at this temperature very long.
4As yet another side note, our sash material has flexible vinyl in it to act as a seal against water infiltration. This material has plasticizers in it that will benefit the impact of the finished product when it is recycled into rigid vinyl. This will absolutely benefit the impact of vinyl.