Kuraray Poval™
for Textile
SizingKuraray Poval™

Kuraray Poval™
for Textile
Sizing
The textile manufacture of spun yarn, which has grown based upon cotton,
has a long history, and starch was used as a warp size from its beginning. As
the use of polyester and polyester cotton yarn has increased, so have thedemands on textile size. The need for productivity and quality has justified
the higher cost of PVOH compared to starch. As weavers get used to theadvantages of PVOH, it has become common to use PVOH on cotton yarns,with or without starch in the size. Kuraray Poval™ is manufactured withcareful control of degree of polymerization and degree of hydrolysis. Kuraray
Poval™ solution forms a film very easily. Films of PVOH
are superior to other resins in tensile strength,
tear strength and abrasion resistance. Kuraray
Poval™ absorbs moisture less than otherwater-soluble resins, such as acrylic resin,starch, etc.
Kuraray Poval™ requires less humidity
in the weave room. Besides, Kuraray
Poval™ has excellent adhesion,
especially to synthetic fibre. Overall,
Kuraray Poval™ is consistently inhigh quality giving excellent efficiency in weaving over wide rangeof fabrics and looms.

2Advantages of Kuraray Poval™
▪ Good Adhesion; excellent strength and abrasive resistance of the formed
coating ⇢ Excellent protective action to the yarns, and minimium warp
breakage during weaving ⇢ Higher weaving efficiency and better quality of thefabrics. Decreasing rate of warp breakage is 20% ~ 50%.
▪ Effective in sizing performance with low size add-on.
▪ No size drop during sizing or weaving ⇢ Better working environments and lesscleaning work.
▪ Weaving under relatively low humidity ⇢ Better working
environments and greater work efficiency.
▪ The best humidity in weaving room is 70 ~ 75% R.H.
▪ Uniform properties and effectiveness of a size
⇢ Stable weaving efficiency.

Grades for Textile
PVOH Production Process
Vinyl acetate monomer
Polymerization

Polyvinyl acetate
Hydrolysis( CH2–CH ) n

CH2=CHOO

C=O

C=O

CH3

CH3
Partially Hydrolyzed

Fully Hydrolyzed( CH2–CH )Polyvinyl alcohol( CH2–CH ) xnOH

( CH2–CH ) nOOH

(PVOH)C=O
n=X+Y

Factors Dominating PVOH Properties
1) Degree of Polymerization
Typical degrees of polymerization (n)500~600				Low Viscosity
1700~2400				High Viscosity2) Degree of Hydrolysis
Showed by mol%:x100
Typical degrees of hydrolysis
980~99 mole %				

Fully Hydrolyzed

87~89 mole %				

Partially Hydrolyzed
3CH3

Grades of Kuraray Poval™
Grade Kuraray Poval™

Standard
Type

Anti-foaming/
Defoaming
type

Viscosity [mPa•s]

Hydrolysis[mol%]

Volatile Max[%]

Ash Max
[%]

pH

5-88

5-88 MB

4.6 - 5.4

86.5 - 90.0

5.00.4

5.0 - 7.0

20.5 - 24.5

87.0 - 89.0

5.0

0.4

5.0 - 7.0

27.0 - 33.0

87.0 - 89.0

5.0

0.4

5.0 - 7.0

40.0 - 48.0

87.0 - 89.0

5.0

0.4

5.0 - 7.0

27-96

24.0 - 30.0

95.5 - 96.5

5.0

0.4

5.0 - 7.0

17-94

14.5 - 18.5

92.5 - 94.5

5.0

0.4

5.0 - 7.0

5-98

5.2 - 6.0

98.0 - 99.0

5.0

0.6

5.0 - 7.0

28-98

25.0 - 31.0

98.0 - 99.0

5.0

0.4

5.0 - 7.0

22-88 SB

22-88

Partially
Hydrolyzed

22-88 PK
30-88 SB

30-88

30-88 DB44-88
MediumHydrolyzed
Fully
Hydrolyzed

Specifications

44-88 SB

Figure 1: Dissolving Rate ofKuraray Poval™ in Water

Table 1: Percentage of Affinity of Kraray Poval™ with Various Kinds of Fibers

-9
850

250
204060

28-98

22-88

5-98

5-88

Cotton*100

9295

115

Viscose rayon

100

9595

93

Bamberg

100

120

97

110

Acetate100

300

120250Vinylon

100

105

100

115

Nylon

100

21090

190

Polyester

100

195

110

250

80

Note:1001) The affinity of other grades of Kuraray Poval™
compared with that of 28-98(=100)
2) * Bleached cotton is used.

Dissolving Temperature - °C
100000
80000
60000
40000

20°C
40°C
70°C

20000

100000
80000
60000
40000

20°C
40°C

5-98

200
100
80
60

40°C
70°C

10000
8000
6000
4000

2000
1000
800
600
400

20°C

22-88

20000

28-09

10000
8000
6000
4000

Viscosity-CPS

Figure 2: Viscosity Concentration
Relationship for
Aqueous Solutions of Kuraray
Poval™ at Various
Temperatures

70°C

2000

Viscosity-CPS

0

Grade of PVOH Fibers

60-98
28

598-88
44

5-88

75

23-8
8

Solubility of PVOH after 30 mins

100

1000
800
600
400
200
100
80
60

2020108641086422

1

20°C
40°C

5-8870°C1024681012144- %Concentration

16182002468101214Concentration - %161820Guidelines to use Kuraray Poval™
PVOH is commonly used for warp sizing in combination with starch. Through a lot of experiences in the field, it has been
proved that the following two basic methods, which draw best performance of PVOH and starch are the nost suitable forwarp sizing.

“PVOH rich method” and “Starch rich method”
PVOH:Starch 				PVOH method
7:3
Starch:PVOH 				7~8:3~2

Starch rich method

Residual Strength of Sized Yarn after
Abrasions by Stationary Weaving

Abrasion Resistance

1005'Fluff B

Cumulative Distribution - %Goodindingestancon resi

Abrasi80

3'2'6002.557.5

10Weight part PVOH

107.5

5

2.50

2 2'

1'4'3'40

20

1'028-98:
Corn Starch=7:3.
Size take up 8.1%

3 3' 28-98:
Corn Starch=1:5
Size take up 11%

2'Bad
Weight part PVOH

Size Composition:
1 1' 28-98 only		 Size take up 5.4%

4'4 4' Corn Starch only.
Size take up 15%

Unabrased
AbrasedTensile Strength - G/EndComposition of Mixtures

1'2'3'4'			5'			: Abrasion of 10,000 cycles on loom
: Abrasion of 3,000 cycles on loom
: Un-sized yarn

Guides with fabric formulation with Kraray Poval™
Fiber: 100% Cotton
Yarn: 35/1 to 50/1

Weave: Medium to Tight

Fiber: 100% Cotton
Yarn: 10/1 to 20/1

Weave: Denim

Size Formula

ShuttleRapierProjectile Air Jet

Size Formula

RapierProjectile Air Jet% PVOH

80

80-10080-10065-100% PVOH

0-15

80-100% Starch

2020-020-0

35-0% Starch

100-8520-0

7715-015-0

13-1113-11% CMC

% CMC
% Wax

7-107-107-107-10% Wax% Urea0-66-06-06-0% Urea

0-60-60-6% Acrylic% Acrylic% Polyester% Polyester% Other% Other% Add-On
Note:

Shuttle11-1214-11

14-11% Add-On

13-10%Wax and additives based on total of PVOH, Stach and CMC.

Note:

5%Wax and additives based on total of PVOH, Stach and CMC.

Key points of sized yarn and size for air jet loom
Sized yarn

▪ Good shedding▪ Good fluff binding▪ Smoothness▪ Proper size take-up (15% morethan conventional looms)▪ Proper viscosity of size solution▪ Smoothness of size film

▪ High abrasion
resistance▪ High abrasion resistanceto stand up to high speed
motion (reed, heald,dropper etc.)▪ Film properties of size
(strength, elongation, pliability,moisture absorbency,smoothness)▪ Good shedding▪ Cohesive performance offibers▪ Good elongation, pliability, smoothness to standup to high speed▪ Adhesiveness▪ Permiability▪ Smoothness▪ Pliability▪ Anti-static property▪ Non-stickiness▪ High abrasion
resistance▪ High abrasion resistanceto stand up to high speed
motion (reed, heald,dropper etc.)▪ Adhesiveness▪ Pliability▪ Smoothness▪ Film strength & elongation▪ Uniform quality▪ The quality of raw yarn
▪ Uniform size-take-up▪ The stability of size solutionviscosity▪ Good compatability of sizing
materials

Spurn yarn

Filament

Common withspun & fil.

Sizing material▪ Good desizability

6▪ Solubility of size

Slashing
The primary purpose of sizing is to increasing weaving efficiency via reducing warp stops by the application of a protective coating on the warp yarn. On the other hand, the primaryfunction of sizes is to improve abrasion resistance to warpyarns. The effectiveness of sizes varies with mass of add-ons
and types of materials such as PVOH, starch, etc. Abrasion
testing of sized yarns provides a means of comparing the effectiveness of sizes and thus their relative costs, for example,
X pounds of Size A = Y pounds of Size B. Of course, abrasion
resistance is not the only determinant of weaving efficiency.

Besides the size formulation, consistency
and quality of the loom beams make a big
difference in the weave room. Some items
to check for include:
1. Consistency of size add-on from side toside and loom beam to beam.
2. Yarn sticking to the dryer(s)3. Yarns out of lease
4. Size distribution – size mainly on the outside of the yarns to improve abrasion
resistance and penetration of size into
the yarns to help strengthening them.
5. Too much size (shedding, difficult tightweaves)
6. Too little size (abrasion breaks, weakyarn)
The list could be much longer, but the operation of the slasher should be controlled
as any modern industrial process.

Preperation of Kuraray Poval™
*Model495 °C

12325 °Cor below
15 min.

50 min.

110 min.

1. Start stirring. Stirring must be kept for all the dissolving process.
2. Charge Kuraray Poval™ gradually.
3. Start heating up. Raise the temperature 2˚C per minute as standard.
4. After getting 95˚C, continue stirring for 60 minutes, as standard, to get complete solution.

Note: Partially hydrolyzed grades of PVOH tend to form lumps at the time of charging into water. In order to avoid this phenomenon and to achieve rapid and easy cooking, take care of the water temperature
at charging time, the charging rate of PVOH and the stirring speed.

7Adding value toyour products –worldwide
Kuraray Poval™, Exceval™, Elvanol™ and Mowiflex™ are the trademarks for polyvinyl alcohols
made by Kuraray. Their key characteristics — outstanding film-forming properties and high binding strength — add real value to your products. Our polymers are water-soluble, highly reactive,crosslinkable and foamable. They have high pigment binding capacity, protective colloid characteristics and thickening effects. The physical and chemical properties of Kuraray Poval™ makeit ideal for a wide variety of applications, ranging from adhesives through paper and ceramics
to packaging films. Many of our polymers are food contact-approved and thus suitable for foodapplications. Ecologically Kuraray Poval™ is advantageous due to its biodegradability and the factthat combustion does not generate residues. It is available in various particle sizes from granules
to fine powders.
Kuraray produces its wide range of Kuraray Poval™ grades in Japan, Singapore, Germany and theUSA. Kuraray’s global production and service network make us your partner of choice for innovative high-quality PVOH resins.
Kuraray – Here to Innovate.

Headquarters
Kuraray Co., Ltd.
Tokiwabashi Tower
2-6-4, Otemachi
Chiyoda-ku
Tokyo, Japan 100-0004
Phone: +81 3 67 01 1000
infopoval.jp@kuraray.com

Kuraray Poval™
product portfolio
Please contact your local
Kuraray office to discuss theright Kuraray product foryour needs.

Kuraray America, Inc.
2625 Bay Area Blvd.,
Suite 600 Houston, TX77058
United States of America
Phone: +1 800 423 9762

Kuraray Asia Pacific Pte., Ltd.
250 North Bridge Road
#10-01/02 Raffles City Tower
Singapore 179101
Phone: +65 6337 4123

info.kuraray-poval@kuraray.com

infopoval.sg@kuraray.com

Kuraray Europe GmbH
Philipp-Reis-Str. 465795 Hattersheim am Main,Germany
Phone: +49 69 305 85 351

Kuraray China Co., Ltd.
Unit 2207, 2 Grand Gateway
3 Hongqiao Road, Xuhui District,
Shanghai 200030, China
Phone: +86 21 6119 8111

info.eu-poval@kuraray.com

infopoval.cn@kuraray.com

04_2022