warp sizing technology

8/10/2019 WARP SIZING TECHNOLOGY

http://slidepdf.com/reader/full/warp-sizing-technology 1/12

Presented by

HIRUTA RIKEN CO., LTD.

1161 Nishiwaki, Nishiwaki-city,

Hyogo, 677-0015, Japan

Tel: (+81) 0795-22-2134

Fax: (+81) 0795-22-1283

e-mail: [email protected]

HIRUTA RIKEN CO., LTD., a manufacturer of sizing agents and technical consultant on sizing, locate in

the midland of Hyogo, Japan, a traditional production center of so-called “Banshu-ori” or yarn-dyed woven

cloth. We have been offering the best solution in sizing process to global customers through providing our

sizing agents as well as technical information.



Warp si zing is an essential process to coat warp yarns with elastic film and bind fibers of

yarns as lowering fluff or hairiness so that yarns may be so strong that resist the mechanical

strain in weaving process, and maintain or improve weaving efficiency. Quality of warp sizing

is generally evaluated by the following factors:

Cohesive strength

Total strength including elasticity of sized yarn to resist such

mechanical strains in weaving process as tensing, bending, rubbing,

shedding, etc.

Fluff binding

Very important factor to prevent yarns from clinging among yarns. It is

particularly required in weaving a high-density fabric or by a

high-speed air jet loom. Sized yarns without fluff (of which fluff is

lowered well) may be shed smoothly in weaving loom.

Size pickup (SPU)

The amount of size picked up by yarns. An ideal size pickup is

pre-determined according to yarn/fabric construction, by which you

can formulate a size recipe and set squeeze roll pressure and other

mechanical conditions. Size must be picked up by yarn sheet evenly.

Smoothness

& Softness

Another important factor of sized yarn as well as cohesive strength

particularly in weaving high-count yarns into a high-density fabric by a

high-speed air jet loom.

Size cookingconditions

Determine the quality of size solution in terms of viscosity, particle

size, etc. In other words, a good size solution can be prepared in a

good cooking process

Sizing machineconditions

In terms of size box temperature, squeeze pressure, draft, dry

cylinder temperature, etc. which may determine the quality of the

above factors.

Key factors of warp sizing

1/11

Warp Sizing Technology for web




Factor (1) Cohesive Strength

Total strength including elasticity ofsized yarn to resist such mechanicalstrains in weaving process as tensing,bending, rubbing, shedding, etc.

Mechanical strains

Warp yarns are drawn as rubbing on thread eye of droppers, mail of healds, comb of reed,

etc.

2/11





How to improve cohesive strength

Use our sizing agent “ Ketacol-TH” with sponge effect

How to measure cohesive strength

In weaving threads into cloth by looms, the warp must be resistant to such mechanical

strains as tensing bending rubbing, shedding, etc., otherwise yarn may be broken. A number

of such yarn breakages may lower weaving efficiency and quality of woven cloth.

Data of yarn strength in terms of elongation, tenacity, or the like offered by conventional yarn

strength testers are useful for studying yarn quality, but most of them do not correlate to

weaving efficiency to be known in practical weaving process. That is, it is difficult for such

conventional testers to analyze actual weavability of sized yarns.

Conventional cohesion tester (TM

type yarn rubbing and cohesion tester

– the right photograph) developed

several decades ago was the most

useful device.

Nowadays, weavability predictor

developed by Hiruta Riken Co., Ld. is

only device with patented mechanism

(patent No. 601116) to simulate and

apply mechanical strains of looms to

yarns, and to numerically determine

Photo. 1: TM type yarn rubbing and cohesion tester

Yarn cohesive strength. It is already approved worldwide that analysis data obtained by this

device correlate to actual weavability.

3/11





Photo. 2: Our weavability predictor

Mechanism

The front face of the device is shown in the above picture. Yarn to be tested is drawn through the yarn guide.The both ends of yarn are held by yarn terminal and clip guide equipped with a specified weight. And theyarn is clipped on recording pen. Turning on the drive switch rotates the friction disk in which the yarn rubson 11 different-shape friction pieces and receives strains as if it were stressed on a weaving loom.Simultaneously, the recording pen is oscillated on rotating chart paper set on the recording drum. All motionstops when yarn was broken. The number of rotation of friction disk is counted by counter. Chart drawn bythe recording pen may tell the condition of testing yarn particularly when it is elongated.

How to evaluate Rotation speed of friction disk and weight are chosen according to specified loom speed and yarn count tobe tested as follows.

Loom speed(type of loom)

Rotation speed offriction disk

Yarn count(cotton)

Weight

170 ~ 250 rpm(shuttle or rapier loom)

70 rpm2030

90 ~ 100 g80 ~ 90 g

250 ~ 650 rpm(rapier, projectile, or air jet loom)

80 ~ 90 rpm4050

70 ~ 80 g60 ~ 70 g

650 ~ 800 rpm(air jet loom)

90 ~ 100 rpm6080

50 ~ 60 g40 ~ 50 g

Total number of rotation of friction disk may be converted into cohesive strength of tested yarn. Basicstandard of acceptable cohesive strength is calculated from the following formula: acceptable cohesivestrength = (warp density per inch + weft density per inch) x a specific factor (3*).

e.g. in case of twill with density of 124 x 80(124 + 80) x 3 = 612

* The above specific factor (3) is our empirical factor. In case that cohesive strength of a sized yarn is morethan a value calculated by the above formula with the empirical factor 3, the yarn might be woven withweaving efficiency of 90 % or more. However, it is not always adoptable depending on mechanicalconditions of looms, fabric construction, etc. A specific factor to be adoptable for you, therefore, should bedetermined by accumulating correlative data between cohesive strength of each tested yarn and actualweaving efficiency of such yarn to be recorded by looms.

4/11





Factor (2) Fluff binding

Very important factor to prevent yarns fromclinging among yarns. It is particularlyrequired in weaving a high-density fabric orby a high-speed air jet loom. Sized yarnswithout fluff (of which fluff is lowered well)may be shed smoothly in weaving loom.

Shedding angle

Shedding angle of shuttle loom is usually as wide as shuttle with a specified size could move

through shed warp sheets to insert weft, in which fluffs of warp sheets hardly block such

movement. On the contrary, the angle of air jet loom is minimized by prioritizing the speed of

shedding motion. Weft is inserted by linear air jet, but may be blocked by fluffs if they are

many or long.

How to reduce fluff

1. Obtain easy divide by dividing rods of sizing machine

> Use our sizing agent “ Ketacol-TH” with sponge effect

> Obtain 50 % or more voids in the width of squeezing roller

5/11





Percentage of voids (S):

N

S = 1 － ------------------ x 10027 C

How to obtain enough voids:

1) Use multi-size box (two/three/four)

2) Use multi-sheet dividing drying system

3) Use wet dividing rod

S = percentage of voids (%)C = Cotton yarn countN = Number of warp / Working width in inch

2. Set cylinder dryer temperature properly

Cylinder sectionTemp. variation

No. 1 No. 2 No. 3

Flat pattern 100 ºC ＝ 100 ºC ＝ 100 ºC

Conventional pattern 100 ºC ＜ 110 ºC ＜ 120 ºC

Up-to-date pattern 120 ºC ＞ 110 ºC ＞ 95 ºC

Modern sizing machines consist of two-size box and three groups of cylinder dryers. In orderto reduce fluffs, temperatures of two front groups should be set higher than the rear. That is,warp is divided into two sheets of which surface are quickly dried respectively by front dryers,

so that sheets might be again coupled without sticking together on the rear dryer.

6/11





Factor (3) Size Pickup (SPU)

An ideal size pickup is pre-determined according to yarn/fabric construction, by which you

can formulate a size recipe (size concentration) and set squeeze roll pressure and other

mechanical conditions. Size must be picked up by yarn sheet evenly.

Basics of ideal SPU (for regular cotton woven cloth)

Yarn count 10/s 20/s 30/s 40/s 50/s 60/s 80/s

SPU (±1.0 %) 8.0 9.0 10.0 12.0 14.0 15.0 16.0

SPU = Size concentration x Squeezing ratio (*)

(*) 90 – 120 % by polyester/cotton blend

100 – 150 % by 100 % cotton

120 – 170 % by 100 % rayon

100 % or less by 100 % polyester

(depending on machine and squeeze roller conditions)

Factor (4) Smoothness & softness

The amount of size picked up byyarns. Size must be picked up byyarn sheet evenly.

Another important factor of sized yarnas well as cohesive strengthparticularly in weaving high-countyarns into a high-density fabric by ahigh-speed air jet loom.

Weave cross-sectional diagram:Regular woven cloth in normal structure High-dense woven cloth with a defect

(if warp is very hard)

Sizing agent & auxiliaries for smoothness/softness

- Ketacol-TH with sponge effect

- Wax

- Oiling agent

- Softener (surfactant)

- Acrylic resin

- After waxing

Moisture regain (after drying process) for smoothness/softnessIdeal amount of moisture of sized yarn:100 % cotton 6.5 ~ 7.0 %100 % rayon 9.0 ~ 9.5 %100 % polyester 1.0 ~ 1.5 %65/35 polyester/cotton 3.0 ~ 3.5 %

7/11





Factor (5) Size cooking conditions Determine the quality of size solution interms of viscosity, particle size, etc.In other words, a good size solution can beprepared in good cooking process

By a high pressure cooker:

Water

Ketacol-TH®

↓

120°C

⑤ ⑥ Finish

60°C

③ ④ ~35°C

① ② ←Steam

10 min. 15 min. 30 min. 20 min.

Mixing tank High pressure cooker

Wax

Oiling agent

↓

① Draw water (a temperature below 35°C is preferable) with a volume 75 – 80% of

predetermined finished volume. Add Ketacol-TH® as stirring and keep stirring for 10

minutes without heat.

② Keep stirring, and apply steam to increase the temperature to 60°C by 15 minutes.

③ Keep stirring, and transport the size solution to cooker.

④ Start cooking by high pressure cooker and increase the temperature to 120°C by 30

minutes.

Note: Cooking time between ④ and ⑤ should be longer than 20 minutes. And

such cooking time should be constant for every batch so that stable size solution

with a same good quality might be prepared.

⑤ Keep stirring and temperature at 120°C for 20 minutes.

Note: cooking time between ⑤ and ⑥ should be constant also for every batch to

prepare stable size solution.

⑥ Add wax and/or oiling agent in the mixing tank if necessary. Finish cooking by

transporting the size solution to an empty stock tank, check finished volume, and

add hot water if necessary to be a predetermined volume.

Note: add wax and/or oiling agent at the stage ③ if it is difficult to add it at the

stage ⑥

[Cooking conditions may be modified according to type and conditions of cooker]

8/11





By an open cooker:

Water

Ketacol-TH®

↓

95°C 95°C

④ ⑤ Finish

① Draw water (a temperature below 35°C is preferable) with a volume 85 – 95% of

predetermined finished volume. Add Ketacol-TH® slowing as stirring and keep

stirring for 10 minutes without heat.

② Keep stirring, and apply steam to increase the temperature to 95°C by 45 minutes.

Note: control steam flow in order to increase at the rate of 1 - 2°C per minute.

Particularly it is preferable to take more times in the stage between ③ and ④. And

such cooking conditions should be constant for every batch so that stable size

solution with a same good quality might be prepared.

③ Keep stirring (and add wax and/or oiling agent if necessary when the temperature

reached 60°C).

④ Keep stirring and temperature at 95°C for 30 minutes.

⑤ Add wax and/or oiling agent if necessary. Finish cooking by transporting the size

solution to an empty stock tank, check finished volume, and add hot water if

necessary to be a predetermined volume.

Note: add wax and/or oiling agent at the stage ③ if it is difficult to add it at the

stage ⑤

[Cooking conditions may be modified according to type and conditions of cooker]

~35°C

① ② ← Steam

10 min. 45 min. 30 min.

Wax

Oiling agent↓

60°C

③

9/11





Viscosity o f size solution

For better warp sizing, it is important to

maintain ideal viscosity of size solution.

If size solution has extreme high

viscosity, it may not permeate in warp

yarns well which might be rough and

hard in handling touch, and be bound

as a tape (two or more yarns are bound

together). On the contrary, if size

solution without enough viscosity is

applied in warp yarns, their fluffs may

not be laid down well, and/or SPU may

be lower than expected because size

may be easily squeezed out.

In general, ideal viscosity is between 10

and 20 seconds by 6-mm viscosity cup

(the right figure).

6-mm viscosi ty cup

(Dripping completion time for water (25˚C):

3.7 sec.)

10/11





Factor (6) Sizing machine condit ions In terms of size box temperature, squeezepressure, draft, dry cylinder temperature,etc. which may determine the quality of theabove factors.

Size box temperature

Viscosity of size solution may vary with temperatures, which may affect the appropriate SPU

rate. In order to achieve a constant SPU rate, it is necessary to maintain a constant size

temperature.

The use of an automatic temperature control device is essential to obtain a constant

temperature according to the difference of yarn kinds

Yarn kindsIdeal sizetemperature

Remarks

100 % cotton 90 ~ 95 ˚C

Polyester/cotton

CVC90 ~ 95 ˚C

Greige cotton yarn contains cotton waxes of

which melting point is about 85 ˚C. Size

temperature for such yarn must be 90 ˚C or

more, otherwise the yarn might not absorbsize solution but retaining cotton waxes.

100 % rayon 75 ~ 80 ˚CRayon fiber may be broken with hightemperatures

Greige

state

Polyester/rayon 80 ~ 90 ˚C

100 % cotton yarn dyed 75 ~ 90 ˚CIdeal temperature depends on dyeingcondition. Residual fixing agent on fibermight block the penetration of size solution.

Stretching (draft)

It is preferable for warp yarns to minimize draft in sizing process. Ideal stretch rate is 1.2 ~

1.5 % for 100 % cotton and polyester/cotton blend.

Drying temperature (of cy linder dryer)

Modern sizing machines consist of two-size box and three groups of cylinder dryers.

In order to reduce fluffs, temperatures of two front groups should be set higher than the rear.

That is, warp is divided into two sheets of which surface are quickly dried respectively by

front dryers, so that sheets might be again coupled without sticking together on the rear

dryer.

11/11


HIRUTA RIKEN CO LTD

warp sizing technology

Documents