Very few clothing materials are synonymous with ‘water resistant’ as PUL fabric, yet water resistance is just one of the many qualities of PUL fabrics.
PUL fabric is made predominantly of polyester, so it retains most of the benefits of many polyester-based fabrics. It is soft and breathable, and it is also very durable.
These properties of PUL fabric make them very useful today. This article will reveal how manufacturers in the textile industry produce and utilize these unique properties of PUL fabric.
You will also learn about some types of PUL fabric and how to take care of them.
What is PUL Fabric?
The term ‘PUL’ stands for PolyUrethane Laminate; it results from fusing Polyurethane (PUR) chemicals with other fabrics. The mixture of PUR and any treated fabric becomes a PUL fabric.
Although manufacturers can treat any fabric with PUR, it works best with polyester interlock knit fabric. Cotton and Cotton poly-blends are also used but don’t work as well as knit fabric.
Cotton is a woven fabric, and PUL made from woven fabrics are less elastic than those produced from knit fabric. The less elastic fabrics are less resilient and water-resistant than their more elastic counterparts. Hence, interlock knit fabric remains preferable.
A typical PUL fabric contains two layers- a 1mm thick layer of polyester or cotton fabric and a thin layer of polyurethane film bonded on the reverse side; this makes it a compound fabric.
Thermal Stretch and Fuzzy Rubber are other names for PUL fabrics because they stretch and resist abrasion.
Like most fabrics made from polyester and cotton, PUL fabric has a soft feel to it and is breathable. It is also waterproof and relatively easy to clean, making PUL desirable for producing an extensive range of substances.
A Brief History of PUL Fabric
No one can ascertain when PUL fabric was invented and became popular, but tracing the origin of Polyurethane, the chemical used in producing PUL fabric, is more straightforward.
The German scientist, Otto Bayer, invented Polyurethane in the late 1930s, alongside fellow scientists at the research facility- IG Farben Leverkusen. They patented the discovery in 1937.
Bayer continued working on Polyurethane and other chemicals but had to wait another fifty years before using PUL commercially, though not to produce fabric.
Hospitals were one of the first to use PUL fabric for medical beddings and mattress protection. PUL fabric gradually spread to the baby product industry, where they were useful for making cloth diapers.
The textile still uses PUL fabric in many products, from menstrual cloth pads to sportswear. Its waterproof qualities make it ideal for any product in constant contact with moisture.
How is PUL Fabric Made?
PUL fabrics are primarily a product of coating woven or knit fabric with a plastic coating (or laminate). Textile industry workers coat the fabric through a Hot Melt or Solvent Lamination process.
The Hot Melt Process
Hot Melt is a process of bonding a layer of Polyurethane with fabric (preferably polyester) using heat-activated adhesives.
Skilled workers use special applicators to apply the adhesives to the fabric. They must take great care since the glue is highly reactive to air and can set prematurely.
Once the adhesive is successfully applied, the fabric is exposed to air to increase the efficiency of the bond; this process is called curing. Gradually, the adhesive melts into the existing fabric.
As the adhesive reacts to air quickly, special adhesive applicators take great care to limit the polyurethane adhesive to the atmosphere.
Environmentalists generally believe the hot melt process is ideal because the adhesives used are eco-friendly, safe to use around food, and better for human health.
The Solvent Lamination Process
This process is the more traditional method of making PUL fabrics. The process involves using solvent-based adhesives that manufacturers apply on both sides of the fabric.
As adhesives appear in concentrated form, they are mixed and diluted to the proper viscosity with compatible solvents like toluene or methyl acetate.
Manufacturers ensure that there is as little water in the solvent as possible; the accepted standard is a water percentage of 0.1%. The mixed adhesive is applied onto the fabric’s surface and fused.
However, this process creates a lot of wasteful by-products that are toxic and petroleum-based. Many environmentalists view this method as unsafe to use around food and bad for the environment.
Types of PUL Fabric
Many designers categorize PUL fabrics by the layer of Polyurethane used in bonding the fabric and by the fabric used in making them.
Both fabric type and layer size are decided based on the intended results; thicker PUL fabrics are more waterproof than lighter ones.
Here are some types of PUL fabrics:
1-Mil PUL Fabric
The name refers to PUL fabrics with only 1 mm of Polyurethane fused to the fabric, and it is the most commonly found thickness of PUL fabrics.
Their thickness is just good enough for use in making cloth diapers, mattress pads, and baby bibs.
2-Mil PUL Fabric
2-Mil PUL fabrics possess two layers of Polyurethane. They are a thicker type of PUL fabric that is more durable and waterproof than their counterparts.
Their sturdiness makes them ideal for products more likely to face more abrasion. They are essential for many industrial purposes or products like furniture upholstery, wet bags, and cover pads.
Cotton PUL Fabric
In this case, manufacturers make PUL from cotton rather than the more popular polyester fabric. Manufacturers can fuse cotton with either 1-mil or 2-mil layers of Polyurethane.
Like their polyester counterparts, they are soft and breathable; unlike them, they are less elastic and resilient. Their hypoallergenic properties make them famous for making diapers and sanitary pads.
Cotton-Poly PUL Fabric
Cotton-Poly combines the elasticity and durability of polyester and the softness and breathability of the cotton.
They can also have either a 1-mil or 2-mil thickness. Cotton-poly PUL usually comprises a 65/35 or even a 50/50 blend of polyester and cotton. They are instrumental in producing re-washable diapers.
Eco-Friendly PUL Fabric
Eco-Friendly PUL is the newest form of PUL fabric made in response to the outcry of the non-biodegradable wastes produced while making traditional PUL fabric.
Eco-PUL comes from renewable raw materials such as vegetable oils rather than mineral oils. The by-products are free from toxins and other heavy metals that pollute the environment.
Polyurethane is fused with the fabric using a solvent-free lamination process suitable for the environment. As the solvent used is environmentally friendly, many have dubbed it- the Green lamination Process.
Uses of PUL Fabrics
PUL fabrics are very versatile and used in many ways. Some of the uses are dependent on the type of PUL fabric.
Uses of Cotton PUL fabric
Cotton PUL fabrics are exceedingly softer, smoother, and more breathable than other types of PUL fabrics.
They are used to produce cloth diapers, washable sanitary pads, and diaper bags. Cotton PUL is also essential in producing athletic shorts, wet bags, and make-up bags.
Note: Manufacturers use the Hot Melt process when making materials that are more in contact with the human body, such as pads and baby accessories. They indicate it on the fabric, so always look out for this.
Uses of Polyester PUL Fabric
Polyester PUL is thicker than cotton fabric and more sturdy. They are used to make products that are subject to more abrasion.
You will find polyester PUL in mattress pads, Patio furniture upholstery, and cover bags.
Uses of Cotton-Poly PUL Fabric
Cotton-Poly’s unique properties make them particularly useful in producing re-washable diapers.
Other Uses of PUL Fabrics
In addition, PUL fabrics are used to make other items such as:
- Baby gears such as bibs and wet bags.
- Protective coverings such as raincoats and rain hats.
- Reusable swim diapers because of their extra absorbent abilities.
- Table cloths, art smocks, and drop cloths.
- Hospital equipment such as medical beddings, mattress protectors, and the outer covering of waterproof mattresses.
- Reusable incontinence products.
Care For PUL Fabric
Caring for PUL fabrics is relatively easy to care for; a little care would help the fabric last longer.
You can wash PUL fabric with a washing machine or by hand. Use a gentle cycle with a liquid detergent when using a washing machine.
Wash temperature can be hot or warm, ranging from about 65 to 75°C. Run through an additional rinse cycle to thoroughly wash off any trace of detergent. Even the tiniest trace of detergent can weaken the laminate covering of the PUL fabric.
Avoid using fabric softeners, bleaches, natural oils, dyes, or enzymes to avoid destroying the fabric’s color or water repellency.
Although PUL fabrics designed for hospital use can withstand high temperatures, those at home may not be able to. Ensure you check the fabric care label of your PUL clothing.
Air dry all PUL fabric. If you use a dryer, set it to a low heat setting. Avoid direct exposure to sunlight while drying as this would crack up the film over time.
Store the PUL fabric under relatively even temperature; extremely hot or cold temperatures can affect PUL.
Also, avoid exposure to moisture or light while storing. Keeping the fabric in a cupboard away from light is recommended.