Basic information on mechanical bonding method for nonwoven fabric production

1. MECHANICAL BONDING
-STITCH BONDING
-NEEDLE PUNCHING
-HYDROENTANGLEMENT

2. STITCH BONDING

3. NEEDLE PUNCHING

4. INTRODUCTION
• Needlepunched nonwovens are created by
mechanically orienting and interlocking the
fibers of a spunbonded or carded web. This
mechanical interlocking is achieved with
thousands of barbed felting needles repeatedly
passing into and out of the web.

5. THE PROCESS

6. PRINCIPLE OF NEEDLE PUNCHING
Source: textileapex.blogspot.com

7. COMPONENT OF NEEDLE LOOM
1. Needle Loom
2. Felting Needle

8. THE NEEDLE LOOM
• The needle board : The needle board is the base
unit into which the needles are inserted and
held. The needle board then fits into the needle
beam that holds the needle board into place.
• The feed roll and exit roll. These are typically
driven rolls and they facilitate the web motion as
it passes through the needle loom.

9. THE NEEDLE LOOM..cont
• The bed plate and stripper plate.
The web passes through two plates, a bed plate
on the bottom and a stripper plate on the top.
Corresponding holes are located in each plate and it
is through these holes the needles pass in and out.
The bed plate is the surface the fabric passes over
which the web passes through the loom. The needles
carry bundles of fiber through the bed plate holes.
The stripper plate does what the name implies, it
strips the fibers from the needle so the material can
advance through the needle loom.

10. THE NEEDLE LOOM..cont

11. THE NEEDLE LOOM..cont

12. THE FELTING NEEDLE
• The correct felting needle can make or break the
needle punched product.
• The proper selection of gauge, barb, point type
and blade shape (pinch blade, star blade,
conical) can often give the needlepuncher the
added edge needed in this competitive industry.

13. THE FELTING NEEDLE (Needle Gauge)
• The gauge of the needles is defined as the
number of needles that can be fitted in a square
inch area. Thus finer the needles, higher the
gauge of the needles. Coarse fibers and crude
products use the lower gauge needles, and fine
fibers and delicate fibers use the higher gauge
needls. For example, a sisal fiber product may
use a 12 to 16 gauge needle and fine synthetics
may use 25 to 40 gauge needle

14. THE FELTING NEEDLE
(Components)
• Crank
• Shank
• Intermediate blade
• Blade
• Barbs
• Point

15. THE FELTING NEEDLE
(Components)
• Crank
The crank is the 90 degree
bend on the top of the needle.
It seats the needle when
inserted into the needle
board.

16. THE FELTING NEEDLE
(Components)
• Shank
The shank is the thickest part
of the needle. The shank is
that part of the needle that
fits directly in the needle
board itself.

17. THE FELTING NEEDLE
(Components)
• Intermediate blade
The intermediate blade is put
on fine gauge needles to make
them more flexible and
somewhat easier to put inside
the needle board. This is
typically put on 32 gauge
needles and finer.

18. THE FELTING NEEDLE
(Components)
• Blade
The blade is the working part
of the needle. The blade is
what passes into the web and
is where the all important
barbs are placed.

19. THE FELTING NEEDLE
(Components)
• Barbs
The barbs are the most
important part of the needle.
It is the barb that carries and
interlocks the fibers The
shape and sized of the barbs
can dramatically affect the
needled product

20. THE FELTING NEEDLE
(Components)
• Point
The point is the very tip of the
needle. It is important that
the point is of correct
proportion and design to
ensure minimal needle
breakage and maximize
surface appearance.

21. THE FELTING NEEDLE
(Needle Reduction)
Single reduction:-
 has two sections, the shank
and the blade.
Much stiffer
Only for coarse gauge needle
Used to punch stiff fibers
including ceramic materials,
waste fiber blend and shoddy
where needle force are high

22. THE FELTING NEEDLE
(Needle Reduction)
Double reduction:-
 has three sections, the shank,
the intermediate blade and the
blade.
Less stiffer compare to single
reduction
Suitable for finer gauge needle,
32 gauge needle and finer
Used to punch less stiff fibers

23. THE FELTING NEEDLE
(Barb shape)
Rounded Barb Styles
Conventional cut barb needle

24. THE FELTING NEEDLE
(Barb angle)
Fiber compaction is greater with
higher barb angles because the fibers
do not slip off the barb face during
penetration through the fiber batt.
As a result, fabrics can be made
stronger and more dense than if the
barb angle had been lower.
Fabric made with lower barb
angles will be more lofty and
thick; they will generally have a
better hand and be of lesser
strength than if barb angles had
been higher.

25. THE FELTING NEEDLE
(Needle types)
The Pinch Blade
The Fork Needle

26. THE NEEDLE ACTION
• As the needleloom beam moves up and down the
blades of the needles penetrate the fiber batting.
Barbs on the blade of the needle pick up fibers on
the downward movement and carry these fibers the
depth of the penetration.

27. TYPES OF LOOMS
1. The Felting Loom
2. The Structuring Loom- use what are called fork
needles
3. The Random Velour Loom - Special crown type
needles or fork needles are used.

28. MACHINE VARIABLE
• Depth of penetration
• Puncture density

29. MACHINE VARIABLE..cont
• Depth of penetration
The maximum penetration is fixed by the needle
of the machine and depends on the length of the
three sided shank, the distance between the
needle plates, the height of stroke, and the angle
of penetration. The greater the depth of
penetration, greater is the entanglement of fibers
within the fabric because more barbs are
employed.

30. MACHINE VARIABLE..cont
The puncture density
• number of punches on the surface of the feed in the
web is a complex factor and depends on
▫ the density of needles in the needle board (Nd)
▫ the rate of material feed
▫ the frequency of punching
▫ the effective width of the needle board (Nb T)
▫ the number of runs

31. • Tennis Court Surfaces
• Space Shuttle Exterior
Tiles
• Marine Hulls,
Headliners
• Shoe Felts
• Blankets
• Automotive Carpeting
• Automotive Insulation
• Filters
• Vinyl Substrate
• 10.Insulator
• Primary Carpet Backing
• Fiberglass Insulation
Felts
APPLICATIONS OF NEEDLE PUNCHING
Fiberglass Mats
Wall coverings
Composites
Blood Filters
Tennis Ball Covers
Synthetic Leather
Carpet Underlay Pads
Auto Trunk Liners
Interlinings
Papermaker Felts
Felts
Padding
Shoulder Padding
Ceramic Insulation
Kevlar Bullet Proof Vests

32. HYDROENTANGLEMENT

33. INTRODUCTION
• Spunlacing uses high-speed jets of water to
strike a web so that the fibers knot about one
another.
• Japan is the major producer of hydroentangled
nonwovens in the world.
• The biggest producers of spunlaced fabrics in the
U.S. are DuPont, Chicopee and Kendall
corporations.

34. INTRODUCTION..cont
• Was officially introduced by DuPont in 1973
(Sontara®).
• Many different specific terms for spunlaced
nonwoven like jet entangled, water entangled, and
hydroentangled or hydraulically needled.
• The term, spunlace, is used more popularly in the
nonwoven industry.
• Softness, drape, conformability, and relatively high
strength are the major characteristics that make
spunlace nonwoven unique among nonwovens.

35. PROCESS
Spunlacing is a process of entangling a web of loose
fibers on a porous belt or moving perforated or
patterned screen to form a sheet structure by subjecting
the fibers to multiple rows of fine high-pressure jets of
water.

36. MATERIALS USED IN SPUNLACE
TECHNOLOGY
Could be carried out using dry-laid (carded or air-laid) or wet-
laid webs as a precursor.
Mixtures of cellulose and man-made fibers (PET, nylon,
acrylics, Kevlar
Cellulosic fibers are preferred for their high strength,
pliability, plastic deformation resistance and water
insolubility. Cellulosic fibers are hydrophilic, chemically
stable and relatively colorless.

37. ENTANGLEMENT UNIT
the energy is delivered to the web by the water needles
produced by the injector. Therefore, we can calculate the
energy from the combination of the water velocity (related
to the water pressure) and the water flow rate (related to
the diameter of the needles).

38. PROCESS..cont
Various steps are of importance in the hydroentangling
process.
Precursor web formation
Web entanglement
Water circulation
Web drying

39. PROCESS..cont
The formed web (usually air-laid or wet-laid, but
sometimes spun bond or melt-blown, etc.) is first
compacted and prewetted to eliminate air pockets
and then water-needled.
The water pressure generally
increases from the first to the
last injectors.
Pressures as high as 2200 psi
are used to direct the water jets
onto the web.

40. PROCESS..cont
Why need pre-wetting?
 to prevent uncontrolled disturbance of the fiber
arrangement to minimise changes in the MD/CD ratio of the
web
 minimise jet marking when the web is impacted by the
main jets
Enable the web to pass between the first injector and the
support surface
Lightly adhere the web to the conveyor to prevent slippage

41. PROCESS..cont (pre-wetting)

42. PROCESS (support wire)
The conveyor surface may be a permeable, continuosly
woven mesh of metal or polymeric construction, a
solid metal roll, or a sleeve, which is normally
perforated.
Small open area --- formation of dense fabrics
Larger open are --- lower tensile strength
The pattern of the final fabric is a direct function of the
conveyor wire.

43. Spunlace support wire details
PROCESS (support wire)

44. Spunlace support wire and the product
PROCESS (support wire)

45. WEB SUPPORT SYSTEM (CONVEYOR
WIRE)
Plastic wire Metal wire
Good flex resistance
Light weight
Easy to install
Corrosion resistant
Difficult seams
Prone to shower damage
Difficult to control knuckle
height
Moderate temperature
Poor flex resistance
Heavy weight
Difficult to install
Prone to corrosion
Invisible seam
Shower damage resistance
Easier to control knuckle height
High temperature

46. PROCESS (Injector operation)
It has been argued that 10 rows of injectors (five
from each side of the fabric) should achieve
complete fabric bonding .
Injector hole diameters range from 4-10mm and the
holes are arranged in rows with 3-5 mm spacing,
with one row containing 30-80 holes per 25 mm

47. PROCESS..cont
Hydroentanglement is applied on both sides
First entanglement roll acts on the first side a number of
times in order to impart to the web the desired amount of
bonding and strength
A second entanglement roll in a reverse direction in order to
treat and, thereby, consolidate the other side of the fabric.
The hydroentangled product is then passed through a
dewatering device where excess water is removed and the
fabric is dried.

48. WATER SYSTEM
Water is most critical part in spunlace process. Therefore,
there are some requirements for the water as follows:
Large amount of water – about 606 m3/hr/m/injector
Nearly neutral pH
Low in metallic ions such as Ca
No bacteria or other organic materials

49. Water circuit and filtration
Filtration system is a major cost in a hydroentanglement
installation and water quality affects process efficiency.
The quantity of water in the circuit is about 40-100 m3/h
The waste water produced in hydroentanglement is
recycled and circulated back to the main high-pressure
pumps. All impurities must be removed to ensure
efficiency.

50. FILTRATION SYSTEM
Due to the large amount of water consumed, the spunlace
process requires that it be recycled. Therefore, a high
quality filtration system is necessary for the spunlace
process. Some of special filters are listed as following:
• Bag filter
• Cartridge filter
• Sand filter

51. WEB DRYING
When the fabric leaves the entanglement zone the web, it is
completely saturated with water. There are a few steps to
remove water from the fabric. The include:
• Vacuum dewatering system
• Drying system

52. PROCESS (De-watering)
Suction is used to remove excess water from the support
surface during hydroentanglement to prevent flooding.
Flooding leads to energy losses that can caused reduced
fabric strength and interference with the bonding process. It
also produces defects in the fabric.
De-watering can be done using squeeze rollers too.

53. APPLICATIONS OF HYDROENTANGLED
FABRICS
The largest US market for spunlaced fabrics spans from
surgical packs and gowns, protective clothing as chemical
barriers to wipes, towels and sponges for industrial, medical,
food service and consumer applications.
The main reason for wide use of these fabrics in medical
applications is based on relatively high absorption abilities.
 Another important criterion is absence of a binder in the
fabric allowing sterilization of the fabric at high
temperatures.

54. APPLICATIONS OF HYDROENTANGLED
FABRICS
 Wipes
 The earliest applications was a replacements for
woven gauze in products such as laparatomy and x-
ray detectable sponges.
Now, diverse hygiene product such as baby wipes,
personal care, facial cleansing, make-up removal,
food service, industrial and household cleaning
products.

55. APPLICATIONS OF HYDROENTANGLED
FABRICS
 Washable domestic fabrics
 hydroentangled cotton fabrics for semi-durable
bedsheets, napkins and tablecloths – can be washed
up to ten times before disposal.
 High-temperature protective clothing
 hydroentangled aramids, are well established as
protective liners and moisture barrier substrates in
fire fighting garments.

56. APPLICATIONS OF HYDROENTANGLED
FABRICS
 Artificial leather
 widely used as backings for PU coated synthetic
leather.
 Surgical fabrics
 surgical gowns, scrub suits, sheets and drapes for
excellent comfort and softness. In surgical gowns,
infection control is paramount and spunmelt and
composites containing breathable films are favoured
over hydroentangled fabrics where there is a need
for improved barrier protection

57. APPLICATIONS OF HYDROENTANGLED
FABRICS
 Medical gauze
Lining and clothing
Filtration
Automotive