1. Air Filtration Media NAFA TECH2015 April 17, 2015 Embassy Suites DFW
Dallas, TX
Air Filtration Media
Review what nonwoven’s are and how they are made
At this time most state,
You have told me what its not
It is easier to start
Steven Ogle
Instructor

2. Nonwovens Are Not! Knitted Woven Tufted Typically, do not use yarns
Paper
What are nonwovens? Unless we are discussing a specific application it is easier to answer with what they are not
Not Knitted = tee shirt
Woven = canvas
Tufted = rug
Paper
© INDA

3. What Are Nonwovens? Engineered fabrics
Fabric made directly from fibers or resins
Manufactured at high speed
Competitive cost
Excludes most “paper”
Many applications
Nonwovens are everywhere
You typically don’t think about a products components
This is a frequently ask question and I have listed many common answers
Many times the answer is in multitude of applications where we find them
They are all around us everyday we just don’t think about it
© INDA

4. Nonwoven Markets/Applications
Disposables:
Diapers, medical gowns/drapes/wraps, wipes, dryer sheets
Semi-durables:
Filters (air, oil, gas)
Durables:
Automotive, home furnishings, geotextiles
Somewhere between disposable and durable NW are some semi-durables. Usually defined as single use but the use is for longer times
Filtration is a good example. Your home heating and air conditioning filter is deigned for a 3 month life
© INDA

5. Thousands of End Products
Consumer Products; cleaning, health, hygiene and more
© INDA

6. Thousands of End Products
The industry usually lists NW’s into two categories based on the types of products they’re used in
Durable long life and disposable single use applications
They are in your car, your house, your bathroom, and your garage
They back your carpet, they add bulk to clothing and they protect you from the environment.
It’s also in your wallet!
show money………….Crane Paper has supplied mint since 1879
Blend of cotton and linen fibers using wet form technology which we will discuss later today
© INDA

7. Air Filtration Products 3.9% Growth – $13.7MM North America by 2018

9. Nonwoven Air Filtration Media
How are they Made
Raw Materials
Web Forming
Fabric Bonding
Converting – Final Product

10. How Nonwovens Are Made 4 Step Process Select raw material Form a web
Bond web into fabric
Finish/convert fabric
If you remember nothing else I ask you remember this
“Almost any NW can be made these 4 steps”
1) Select the raw material
2) Loosely arrangement the material to form a web
3) Bond the web into a continuous structure
4) Finish the fabric for conversion into final form
© INDA

11. Step #1 Material Selection Staple Fiber Natural Man made Polymer Resin
This is step #1 of the four step process to make nonwoven products. The fiber used in wet and dry laid webs is usually staple meaning they have a known consistent length because they have be crimped and cut or manufactured to a length that is ideal for the intended process. The fiber is then baled for storage and delivery to the NW manufacturing lines.
© INDA

12. A Word About Fibers! Fiber choice critical to end-product
Fiber decisions based on fabric requirements
Strength
Flexibility
Melting point, flexible/brittle temperature (glass transition)
Stability toward its environment (i.e., flame, sunlight)
Dyeability
Cost, availability
When deciding on the proper fiber we ask what do we need/want to fabric to do/be?
Strength – wet or dry, hot or cold, permeant or temporary
The attributes of available fibers are well known and easily obtainable so I will not go deep into them but just highlight a few
© INDA

13. Step #2 Web formation – staple fiber to fabric Carded Air laid
Wet laid
Web formation – polymer to fabric
Spunbond
Meltblown
SMS
Step #2 dry laid staple fiber web forming process
Short staple airlay is what you do so we will only be discussing longer staple airlay processes.
© INDA

14. Materials Web Formation Bonding Finishing Finished Products Roll Goods
Fibers
Polyester
Carding
Calender
Surfactant
Nylon
Air Laid
Through Air
Repellent
Gowns and Drapes
Cotton
Cross-lap
Hydro
Color
Rayon
Wet Laid
Needled
Coating
Paper Tape (Transfusions)
Polypropylene
Adhesive
Other
Pulp
None
Surgical Sponges
Fluff Pulp
Bi-component
Others
This flow diagram shows the 4 steps
Step 1 is to select the right raw material or materials
Fiber in our case
© INDA

15. What Is a Web?
A web is a random structure of loose fiber
Dry laid webs made by carding or air laying
What is Carding
Individual fibers between 1/2”-2” are separated by combing
A web is formed with a high degree of fiber alignment
What is Air Laid?
Individual fibers 1/2” or less are separated & carried by air fiber distribution is very random
A staple fiber web has little structural integrity
And varying degrees of fiber orientation dependent on the web forming process
Carded webs have the most controlled fiber orientation
© INDA

16. Web Carding: Dual Cylinder
Higher throughput and more carding with 2 cylinders
© INDA

17. Air Laid Card
Notice that like a Card this web former has a main cylinder with workers and stripers to separate the fibers and organize them. BUT instead of combing them of the main onto the floor apron they are blown onto it to randomize the fibers and give them loft/bulk
© INDA

18. Air Laid Short Fiber
Like a round flour sifter
© INDA

19. What Is Wet Laid?
Fibers, very short, are suspended in water and then collected on a screen, forming the web
Water is drained, then vacuumed, then pressed, and finally evaporated with heat
Hydrogen Bonding w/paper/pulp
© INDA

20. Wet Laid Process
Slurry 0.1%-1% fiber
© INDA

21. Materials Web Formation Bonding Finishing Finished Products Roll Goods
Polymers
Polypropylene
Spunbond
Calender
Surfactant
Polyethylene
Meltblown
Through Air
Repellent
Gowns and Drapes
Mayo Stand Cover
Polyester
SMS
Hydro
Color
Nylon
Film
Needled
Coating
PLA
Other
PVA
None
Head Gear and Booties
Face Masks
Others
Virtually any Spunmelt nonwoven product can be made with this matrix
© INDA

22. What Is Melt Spinning?
Extrusion of melted polymers to form fibers and webs
Meltspinning:
Spunbond
Meltblown
Just like man made fiber manufacturing
© INDA

23. Spunbond Process
Resin in
Quench and draft
© INDA

24. Meltblown Process
Hot Air attenvates
(not like spunbonding)
© INDA

25. SMS Schematic
Just like a MB sandwich w/SB bread
© INDA

26. Courtesy of Fiberweb PLC
SMS Cross Section SB MB
Note diff in fiber diam.
Courtesy of Fiberweb PLC

27. Coform Process
You can see the meltblown process as shown before but with a pulp feed, hammer mill and blower to introduce the ground wood pulp into the meltblown stream.
© INDA

28. Step #3 Bonding methods Chemical (adhesive, resin, latex) Needlepunch
Spunlaced/hydroentangling
Thermal bond
Step #3 we will discuss ways of bonding the web to form NW fabrics
© INDA

29. Chemical Bonding (Gravure Printer)
This is how Handi Wipes are made.
There is a design patent on the Wavy Line print pattern.
© INDA

30. Chemical Bonding (Dip & Nip)
Dip & Nip is also called Saturation Bonding
Typically, Binder comes in at 40% - 45% solids
For Dip & Nip, solids are reduced to 5% + surfactant
Fabrics will “pick up” 100% -150% of their weight
EXAMPLE:
100 gsm fabric
+ 100 gsm 5% solids
= 200 gsm of fabric + binder at exit
=105 gsm of finished fabric after drying
© INDA

31. Chemical Bonding (Foam Padder)
Foam bonding uses very little water-could use binder as received w/ 40% - 45% solids.
Use air to dilute the binder
DRAW Knife Coater with vacuum to saturate
© INDA

32. Chemical Bonding (Spray)
Sample 19 scrub pad filter
These are dilute solutions of binder and water.
Use this technique on dry-formed-pulp/air laid
Courtesy of Roy Broughton

33. Needle Penetration Show #16 = needles
One sided or two sided needling systems with single or multiple boards
© INDA

34. Dual Entangler
© INDA

35. Courtesy of NCRC – NCSU - 2001
Calendar Bonding
Web passed between two rolls
One or both are heated internally
One or both may be embossed
Heating via conduction
Cooling via convection
This technique is the most common for thin light weight webs
Smooth roll bonding covers 100%
Courtesy of NCRC – NCSU

36. Courtesy of NCRC – NCSU - 2001
Through Air
Hot air
This is very common for highloft products
Show samples of high loft
Fibers can’t be homopolymer:
Web must be a blend of high melt and low melt temperature fibers or Bicomponent fibers
Courtesy of NCRC – NCSU

37. Courtesy of NCRC – NCSU - 2001
Ultrasonic Bonding
Horn
Friction between horn and fabric heats fibers under raised points
Ultrasonic is not very common-it’s too slow.
This is used for finished parts like bag filters Or
as an assembly technic to bond two or more thermal plastic components together
Anvil
Courtesy of NCRC – NCSU

38. Step #4 Converting Examples include: Slitting Pleating Molding
Sheet cutting
Die stamping
Perforations for easy tearing
Pleating
Molding
Assembling
Folding
Packaging

39. Thank You
Steve Ogle