GETTING TO KNOW KEVLAR: THE USES AND CHALLENGES OF COATED ARAMID FABRIC

In the modern era, technical fabrics are revolutionizing countless industries, from automotive to aerospace, protective clothing to industrial equipment. Among these advanced materials, one stands out due to its superior strength and versatility: coated aramid fabric, commonly known by its trade name, Kevlar.

Coated aramid fabric combines aramid fibers’ remarkable strength and durability and the versatility of various coating materials. While highly effective, this innovative material has its challenges. This article will delve into the unique advantages and challenges of Kelvar and its best applications.

EXCEPTIONAL ADVANTAGE:
HIGH PUNCTURE RESISTANCE

The primary advantage of kelvar is its high puncture resistance. Aramid fibers are five times stronger than steel on an equal-weight basis. This strength makes the coated aramid fabric incredibly hard to tear or puncture, surpassing the capabilities of many traditional materials.

When coated, these fabrics gain added resistance to elements like water, oil, and various chemicals, thereby extending their lifespan and functionality. The high puncture resistance makes coated aramid fabric perfect for applications where durability and longevity are paramount.

KEY CHALLENGE:
CONNECTING KEVLAR TO PLASTIC

Despite its numerous advantages, working with coated aramid fabric presents some challenges. One significant challenge is connecting Kevlar to plastic. Due to its exceptional strength, aramid fibers can be difficult to bond with other materials, particularly plastics.

Solution providers must devise creative strategies and use specially designed adhesives or mechanical bonding methods to overcome this. It is a delicate process that requires expertise and precision to maintain the integrity and performance of the coated aramid fabric.

BEST APPLICATIONS OF COATED
ARAMID FABRIC

Given its high puncture resistance and durability, coated aramid fabric is ideally suited for a wide range of applications:

1. COATED ARAMID FABRIC AND PROTECTIVE CLOTHING

Coated aramid fabric is commonly used in the production of protective clothing. Its high puncture resistance and heat tolerance make it perfect for producing body armor, cut-resistant gloves, firefighting uniforms, and spacesuits.

2. AEROSPACE AND AUTOMOTIVE INDUSTRIES

In the aerospace and automotive industries, where strength-to-weight ratio is a key concern, Kelvar is often used. Its lightweight, high-strength characteristics make it ideal for producing parts that withstand high stress and impact.

3. SPORTS EQUIPMENT

Coated aramid fabric’s high tensile strength and puncture resistance make it a valuable material in sports equipment like racing sails, bicycle tires, and high-performance gear.

4. INDUSTRIAL APPLICATIONS

Coated aramid fabrics come into play in industries where equipment must withstand harsh conditions. These fabrics make heat-resistant and cut-resistant covers, conveyor belts, and high-pressure hoses.

5. COATED ARAMID FABRIC AND ELECTRONICS

Kelvar is also used in the electronics industry due to its excellent thermal, chemical, and dimensional stability.

In conclusion, coated aramid fabric offers boundless possibilities across various industries with its unique combination of high puncture resistance and exceptional durability. While the challenge of connecting Kevlar to plastic exists, technical advancements and innovative solutions continue to widen its applicability. As we continue to explore and understand its full potential, the coated aramid fabric is set to redefine the future of material science and applications.

E Squared – A year in Review – 2023

As we look back at our challenges and accomplishments in 2023 we are thankful for our team of employees who drive our efforts of innovation, quality and success and our customers who establish standards that we always strive to exceed.

Every year starts with a big inhale as we start the journey to achieve our goals and objectives not only on sales success, but also in the advancement of our technologies and capabilities both internal and external.

Blogs, blogs and more blogs. In 2023 we provided over a dozen blogs and technical papers to our contacts. Many of these blogs have a genesis with our customers. Many times we are asked to expand on a topic or application and our team always delivers. Visit our library of blogs

Trade shows, always a pleasure. In 2023 we participated in 10 trade shows and Industry events.  This is always the best opportunity to see customers and meet prospects.  Some of the highlights came at events like USINFI Outlook, ATA Expo, WWETT Expo, Work Boats Expo, Geosynthetics Conference and many others.  In 2024 we look forward to seeing you at some of these expos along with several others like Geotechnical Frontiers and the NASSCO Conference. Meet us at any of the events listed on our homepage.

Government Advocacy, someone has to speak up for our American Industries.  Whether it is the USINFI, GMA or NASSCO lobby days. We are always ready to head to D.C. to represent the interests of our industries. These events occur 4 – 6 times a year and allow an inside look at how our government works, and sometimes doesn’t work. This could be for long established programs like the Berry Amendment and its sibling the Kissell Amendment, both ensuring that US manufacturers are first in line when it comes to DoD and DHS spending. When it comes to spending of DOT, FAA , EPA and other agency spending we help drive the use of American manufactured geosynthetic products for bills like the Bipartisan Infrastructure Law (BIL) Overview, including Buy American, Build America  (BABA), Water Resources Development Act (WRDA), FAST Act,  Annual FAA Reauthorization Act and many others.  We encourage customers, suppliers and competitors to get involved with advocacy efforts. After all it is your tax dollars that are being spent.

Looks like we are going to need a bigger boat! In 2023 we saw the grand opening of our latest manufacturing facility in Bluefield, VA.  This state of the art manufacturing facility will lead the way for E Squared growth and not only shows our commitment and investment to American Manufacturing, but also to the advancement of our capabilities, innovation and employees.

Hiring is always fun.  In 2023 we added a new member to our management team. Anthony Ahmed joined E Squared in the position of Senior Market Manager.  Anthony has a vast knowledge of geomembranes and their applications with over 7 years of experience.  In this role Anthony will expand our presence in the environmental, water management and infrastructure markets. Welcome aboard Anthony!

Innovation and new products. You are either moving forward or moving backwards, There is no holding your position.  E Squared never settles with the status quo when it comes to product innovation.  In 2023 we had major achievements in the introduction of many new and improved products.  Acoustic Barrier Substrates, Fish Grade Certified Geomembranes, Marine Safety and life preserver substrates, Trenchless Pipe Rehabilitation, CIPP to name a few.  To learn more about these and other new product innovations visit our innovation section here or speak with one of our Market Specialists.  Yes, that was a sales pitch.  I should also mention to follow E Squared on our LinkedIn page.

As we end 2023 we are pleased to announce further expansion of our global presence with a Partnership with The Shann Group with warehouse and sales offices in Australia, New Zealand and Fiji.  The Shann Group will provide distribution throughout Oceania, This is a major step forward in our efforts to provide our innovative  products globally.

We ask you to join us as we move into 2024 with expectations of continued success for E Squared and our customers.

Welding Techniques for CIPP

Airtight CIPP tube is fabricated by stitching the adjoining edges of the coated felt and sealing the seam area with a thermoplastic sealing strip.Tubes are usually sewn together with an edge-to-edge (butt) sewn seam to create an even seam surface and thickness. Sealing options include direct extrusion of a compatible polymer or welding of thermoplastic seam tape by hot air/gas or solvent. Careful consideration of the different processing factors involved in these sealing methods are necessary for consistent seam quality and throughput.

This chapter provide further insights on the influence of the thermoplastic polymer properties and critical quality aspects of seam tape/sealing strip for hot air and solvent welding techniques. Using compatible thermoplastic polyurethane (TPU) and polyolefin (TPO) polymer extrusion or seam tapes for TPU- and TPO-coated felt is recommended to ensure superior adhesion to the coating of the main/lateral liners as well as maintaining the required mechanical strength, thermal and chemical resistance characteristics of the CIPP tubes.

Extrusion technique

Extrusion is an advanced and effective technique in sealing the sewn seams to form the final tubes. Determination of the melt flow index of the TPU or TPO pellets is necessary to ensure optimal processing of the TPU or TPO, which includes barrel temperatures, screw speed and pressure control to produce a homogenous, Higher melt flow TPU or TPO usually requires less heat to process. A controlled extrusion process is critical for consistent gauge and melt viscosity for strong adhesion (film tearing bond) to the TPU or TPO-coated layer on the sewn seam.

Hot-air welding technique

Hot air welding has proven effective and durable in the sealing of CIPP tubes using compatible seam tapes. This technique involves thermally welding the interface of the TPU/TPO seam tape and coating on sewn seam of the tube with a heated air flow. Hot air welds are permanent, airtight and come to full weld strength almost immediately. Determination of hot air temperature (typically +485oF), pressure and speed controls according to the film thickness and TPU/TPO thermal properties is important to ensure that the crystalline thermoplastic layers softens and melts to form a permanent weld when the thermoplastic cools. If excessive heat is applied, thermal degradation may occur where the thermoplastic sealing strip can shrink or burn while insufficient heat results in a defective weld due to poor fusion on the thermoplastic layers.

The weld characteristics of the thermoplastic TPU depends on the amount of crystallinity, where softer TPU tapes typically require less heat to thermally fuse. Table below indicates increase of temperature by 30 oF with increase of TPU shore hardness.

Data obtained using a MillerweldmasterT300 Flex hot air welding machine. Speed 10 FPM, 8 psi, 485 – 550 oF.

Solvent welding technique

Solvent welding is a process where solventwith no dissolved polymer is applied to soften and dissolve the surface of the interfacing thermoplastic layers.This process forms a cohesive connection through molecular diffusion between the contacting layers. Tetrahydrofuran (THF) is used for solvent welding TPU due to its high solubility strength in creating a high-strength weld after a short time. The table below shows that TPU with higher shore A hardness tends to be more resistant and requires a longer reaction time than softer TPU’s. We also found that the presence of additives in TPU matrix can influence the strength of the solvent weld.

FTB – film tearing bond

The following criteria are important for high-quality solvent welding:

  • Compatible TPU matrix and shore hardness for effective solvation and allowing THF to permeate out to form a strong weld bond.
  • Suitable thickness of the seam tape – typically comparable to the liner coating.
  • Excellent lay flat quality and gauge consistency of the seam tape to avoid air pockets.
  • Skills and knowledge on the operator part is integral to obtain a consistent high-quality weld.

In practice, compatible thermoplastic TPU or TPO polymers is recommended for sealing the sewn seams in the final CIPP tube fabrication and careful determination of sealing process conditions according to the physicochemical properties of the seam tapes is required for superior weld strength and performance.

 

The Importance of CIPP and it’s Benefits

CIPP (Cured In Place Pipe) technology, also known as trenchless technology or in-situ pipe repair, enables the restoration of damaged sewer systems without the requirement for excavation or trench digging. This process involves deploying CIPP tubes using water, steam, or air pressure to line the existing pipes.


In our forthcoming four-part series, we will delve into various aspects of utilizing CIPP technology, with a focus on the following topics:

  • The Importance of CIPP and its Benefits.
  • Welding Techniques for CIPP and Implementation.
  • Ensuring Quality Control in CIPP Applications.
  • The Difference in Main Line CIPP and Laterals

The deteriorating state of wastewater systems in North America and Europe, along with the growing volume of wastewater worldwide, have resulted in the rise of pipes bursting and the overflow of wastewater outside of the pipe. The majority of pipes are buried underground, which may result in expensive repairs requiring excavating roadways and leading to major traffic delays for many days.

The concept of lining existing pipelines with a flexible material impregnated with resin was first explored in the 1950s. Early experiments focused on using fiberglass-reinforced materials as liners. The primary motivation was to find a less disruptive and more cost-effective method for rehabilitating aging sewer and water pipelines.

In the 21st century, CIPP technology continued to advance with improvements in liner materials, resin formulations, and installation techniques. It also found applications in rehabilitation projects for larger-diameter pipelines, stormwater systems, and other critical infrastructure. The technology’s versatility and ability to extend the life of pipelines made it a valuable asset for addressing the challenges of aging infrastructure.

Today, approximately 50% of all damaged pipes are being repaired using CIPP technology. In the U.S., trenchless technology continues an upward growth trend. It has captured nearly half of the $3.4 billion market for sewer line rehabilitation and about an eighth (12.9%) of the $1.5 billion spent on repairing potable water pipes, according to the 15th Annual Municipal Infrastructure Survey conducted by Underground Construction (Oildom Publishing Co., Houston, Texas).

Importance of CIPP and it's Benefits

Trenchless pipe relining is a popular technique for repairing damaged or clogged sewer lines, water lines where the pipes are pre-fabricated at the manufacturing facility and are pre cut and welded to form the tube, the liner goes through the wet-out process, where the line is saturated with a polyester, vinyl ester, or epoxy resin. The line is then transported using a refrigerated truck to the job site and is deployed at the job site utilizing steam, hot water or UV to form the shape of the damaged pipe, making it both more economical and effective.

The core principle behind CIPP involves inserting a flexible liner, often composed of materials like polyester, fiberglass, or felt, into the damaged or compromised pipe. Once in position, the liner is impregnated with a thermosetting resin that, upon curing, hardens to create a new, structurally sound pipe within the existing one. 

  1. CIPP typically consists of a resin-impregnated felt or fiber sleeve. With the resin in an uncured state, it forms a flexible, conformable tube that can be inserted into a damaged pipe. Some sleeves are manufactured inside out and are inverted as they are pushed into the existing pipe via air or water pressure.

importance-of-cipp-and-its-benefits

Cross Section of a damaged pipe (before), and after rehabilitation using CIPP (After) 1

The CIPP technology was developed as a solution to the challenges posed by traditional pipeline repair and replacement methods, which often involve disruptive and costly excavation. CIPP offers several benefits, including:

1. Cost Savings: CIPP eliminates or significantly reduces the need for extensive digging, resulting in reduced labor and equipment costs associated with excavation.

2. Minimal Disruption: The non-disruptive nature of CIPP means that road closures, traffic disturbances, and disruptions to daily activities are minimized, making it ideal for urban areas.

3. Environmental Considerations: CIPP reduces the environmental impact by minimizing soil disturbance, energy consumption, and emissions from construction equipment. It also extends the lifespan of existing infrastructure, reducing the need for new material production.

4. Versatility: CIPP can be used on various types of pipes, including those made of clay, concrete, cast iron, PVC, and more. This versatility makes it suitable for a wide range of pipeline rehabilitation projects.

5. Structural Reinforcement: The cured resin inside the liner not only seals leaks and prevents infiltration but also reinforces the structural integrity of the pipeline.

6. Speed of Implementation: CIPP projects are often completed faster than traditional methods due to reduced preparation and construction time, minimizing service interruptions.

E Squared has been working closely with all the major CIPP pipe manufacturers, along with the TPU vendors, felt and non-woven manufacturers across the world, and the leading manufacturers of welding and sewing machines, to ensure that we have the right solution for your application. Our Research and Development facility at Hillside, New Jersey, is working on new development projects, including high-pile knits, TPO coatings and hybrid fleece. E Squared’s dedication in the CIPP industry can be seen with the opening of our new manufacturing facility in Bluefield, VA which is dedicated to manufacturing coated felts for CIPP applications.