Recycled polyester, also known as rPET, is obtained by melting down existing plastic and re-spinning it into new polyester fiber. While much attention is given to rPET made from plastic bottles and containers thrown away by consumers. In reality, polyethylene terephthalate can be recycled from both post-industrial and post-consumer input materials. But, just to give an example, five soda bottles yield enough fiber for one extra-large T-shirt.
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Let’s make a pros and cons of recycled polyester.
1. Keeping plastics from going to landfill and the ocean
Plastic has been found in 60 percent of all seabirds and 100 percent of all sea turtle species because they mistake plastic for food.
Taking plastic waste and turning it into a useful material is very important for humans and our environment
2. rPET is just as good as virgin polyester but takes fewer resources to make
Recycled polyester is almost the same as virgin polyester in terms of quality, but its production requires 59 percent less energy compared to virgin polyester, according to a 2017 study by the Swiss Federal Office for the Environment.
1. Recycling has its limitations
Many garments are not made from polyester alone, but rather from a blend of polyester and other materials. In that case, it is more difficult, if not impossible, to recycle them.
Even clothes that are 100 percent polyester can’t be recycled forever.
After all, even though rPET takes 59 percent less energy to produce than virgin polyester, it still requires more energy than hemp, wool, and both organic and regular cotton, according to a 2010 report from the Stockholm Environment Institute
2. The process of recycling PET impacts the environment, too
The chips generated by mechanical recycling can vary in color: some turn out crispy white, while others are creamy yellow, making color consistency difficult to achieve. Inconsistency of dye uptake makes it hard to get good batch-to-batch color consistency and this can lead to high levels of re-dyeing, which requires high water, energy, and chemical use
3. Recycled polyester releases microplastics
A paper published in 2011 in the journal Environmental Science Technology found that microfibers made up 85 percent of human-made debris on shorelines around the world. It doesn’t matter if garments are from virgin or recycled polyester, they both contribute to microplastics pollution.
Recycled polyester, often called rPet, is made from recycled plastic bottles. It is a great way to divert plastic from our landfills. The production of recycled polyester requires far fewer resources than that of new fibers and generates fewer CO2 emissions.
There are 2 ways to recycle polyester: For mechanical recycling, plastic is melted to make new yarn. This process can only be done a few times before the fiber loses its quality. Chemical recycling involves breaking down the plastic molecules and reforming them into yarn. This process maintains the quality of the original fiber and allows the material to be recycled infinitely, but it is more expensive.
Different fibers have different characteristics. You may already know a lot of them just by handling them in your knitting, weaving, embroidery, or crochet. The length of a single unit of the fiber - the staple - can determine many things about the thread you will get. A short fiber is not usually a good base for thick single, whereas a long-staple can be. But a long staple fiber will sometimes not give a nice thin thread because it may become scratchy when tightly twisted into a thin thread. Slubby yarn can be great fun to work with, but the finished product may not be as sturdy as the same piece made from a uniform yarn. How much wear you get can effect what you do with the yarn. Low twist yarns are weaker, softer, lightweight, less abrasive resistant, flexible, have more loft, and pill. High twist yarns are stronger, harder, heavier, more abrasive resistant, less flexible, cooler. For example: woolen yarns - made from all lengths of the fiber (carded wool) is usually spun in a low twist yarn. Worsted yarns were spun from the long fibers only (combed into top with fibers parallel) into a high twist yarn that is usually denser and smoother, making a cooler, but wind resistant fabric. The sett or gauge in the work up of the piece also determines a lot and in figuring the gauge or sett, you sometimes need to look at the yarn. A low twist yarn woven tightly sett or knitted on a close gauge will give a more sturdy and long lasting piece than a low twist yarn worked up loosely.
Abrasion resistance - the ability to withstand wear from repeated rubbing. From good to poor: nylon, linen, acrylic, cotton, wool (coarse), silk, wool (fine), rayon, acetate.
Absorbency - comfort of a garment can be greatly affected by the fiber's ability to regain moisture. If a fiber cannot absorb moisture, it feels clammy, and can plaster itself to your skin. Absorbent fibers have less static cling. All natural fibers normally contain 10% or more water, and some can absorb up to 30% of their weight in water and feel dry to the touch. Synthetic have little or no absorbency (although, several of them do absorb oil). - from best: wool, flax, hemp, silk, cotton, ramie, nylon, acrylic, polyester.
Chemical, mildew & moth resistance - ph levels in your cleaning and dyeing baths can damage some of your fibers. Below 7 is acid, and above 7 is alkaline. Wool is resistant to acids. Silk is resistant to organic acids but damaged by mineral acids. Cellulose fibers are harmed by acids - even vinegar can do some damage. Alkaline solutions can also damage protein fibers, but cellulose fibers are more resistant. Use mild detergents to wash yarns, and fibers, remember that the minerals in your water (if you have hard water) can also do a number on your fibers. When washing protein fibers, a little vinegar (1T per qt of water) in the NEXT-TO-LAST rinse water will neutralize any alkaline residue. Chlorine bleaches will not damage cellulose fibers if used properly (according to directions), but should never be used on protein fibers. If you need a bleach for protein fibers, peroxide is sometime used - remember what it can do to your hair. The moth attacks wool, hair, fur, down & feathers of animals. Carpet beetles eat protein fiber including silk, and silverfish will eat cotton. I use lavender, bay, eucalyptus, basil, pennyroyal, tansy, cedar, or rosemary. These do not kill, only keep at bay the insects. Careful cleaning and hopefully, continual turnover will keep your place more free of pests than any moth repellants. Cellulose fibers can suffer from mildew damage; it weakens and stains the fibers. You can bleach them after a careful washing.
Elasticity - all fibers can be stretched - but they do not all have the same breaking point or the ability to recover from the stretch. The ability to recover from the stretched state is important when planning a project - clothing needs that to return to its original shape after the normal wear, but dimensional stability may be needed in other products. Recovery may not always be immediate and the time held under tension also affects its ability. Higher percentage of recovery to lower: wool, silk, rayon, cotton, ramie, flax/linen.
Flammability - wool offers the greatest resistance to fire, and other protein fibers are usually self-extinguishing. Cellulose fibers continue to glow after they are removed from the flame. Synthetic fibers vary, but range from acrylic that is so hot that it can ignite a combustible material if it drips on it, and others that have vinyl cyanide or vinyl chloride whose fumes are toxic.
Heat sensitivity - meaning wet & dry heat. Silk, wool and all protein fibers should never be boiled, simmering is the best for washing & dyeing. Cotton, linen, and other cellulose fibers are quite heat resistant and can be boiled safely.
Pilling - short fibers work loose from the yarn and tangle around the ends of neighboring fibers. They form little fuzzballs, which are held in place by the longer fibers in the yarn. Proper fulling of wool reduces or eliminates pilling. Resistance to pilling from good to poor: silk, flax, cotton, wool, acrylic, polyester, nylon.
Shrinkage - compare to a rubber band - it simply returns to its natural size. Shrinkage is caused by the way we spin, weave, and finish the fabric. If yarns are dipped in water or washed, and allowed to dry in a relaxed state before being woven (or knitted) they will cause less shrinkage.
Strength - length of individual fibers, and amount of twist in the yarn can help determine the strength of the yarn, but some fibers are stronger than others: in order from strongest: flax, hemp, silk, nylon, polyester, cotton, acrylic, wool, rayon.
Sunlight resistance - from good to poor: acrylic, polyester, flax, cotton, rayon, acetate, nylon, wool, silk. Not usually a problem for clothes, but for upholstery, rug, etc.
Warmth - retention of heat from high to low: silk, angora, wool, cotton, ramie, flax. Yarns can be spun to trap air and therefore be warmer. Woolen spun yarns being in that category.
Weight - from heaviest to lightest: cotton, flax, ramie, rayon, hemp, polyester, wool, silk, acrylic, nylon.
Wrinkle recovery - from good to poor: wool, silk, cotton, rayon, ramie, flax. When relaxed fibers are used then there is less tendency to wrinkle. Blocking all your yarns, make it necessary to always block your finished pieces, and properly finished hand-woven pieces have a better wrinkle recovery.
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