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Draft Copy

Textiles– High Tenacity Yarn of Nylon or other Poly-amides Specification

(HS: 5402.19)

Foreword

High tenacity Nylon or other polyamides:

High tenacity yarn: A yarn with a significantly higher breaking tenacity

than others of the same generic category, generally used because of that

main characteristic.

Tenacity is the customary measure of strength of a yarn; it is usually

defined as the ultimate (breaking) force of the yarn (in gram-force units)

divided by the denier or tex. Because denier or tex is a measure of the linear

density, the tenacity works out to be not a measure of force per unit area, but

rather a quasi-dimensionless measure analogous to specific strength.

Identifying High-Tenacity and Non-High-Tenacity Yarns:

The HTSUS defines high-tenacity yarn as yarn having tenacity,

expressed in cN/tex (centinewtons per tex), greater than the following:

For single yarn of nylon or other polyamides: 60 cN/tex.

For multiple (folded) or cabled yarn of nylon or other polyamides: 53

cN/tex.

The force exerted at the breaking point is then divided by the linear density to

calculate the tenacity.

In addition to the above, there are numerous guidelines which, although

not conclusive, may suggest whether a yarn is high-tenacity:

Industrial yarns would seldom be bleached or colored or dyed.

Filament “textile yarns” (the term the trade uses for yarns made for

apparel and furnishings) generally would not exceed 900 denier (990

decitex), while “industrial yarns” (the trade term for yarns for industrial

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applications such as tires) would generally be 1100 denier (1210

decitex) and higher.

Textile yarns would generally be shipped in protective cartons because

of their fragility, while tubes of the tougher industrial yarns may be

stacked directly on skids and shrink-wrapped in plastic.

If a yarn can be easily pulled apart by hand, it is probably not a high-

tenacity yarn.

The ultimate consignees or end-users of high-tenacity industrial yarns

would normally be tire or rubber product manufacturers or converters.

The automotive sector is by far the largest end-use market for these

yarns. Another major application is in reinforcing automotive and

appliance belts. High-tenacity yarn also has some other minor end uses

such as thread for shoes, webbing or strapping, and ballistics fabrics

used to make bulletproof clothing.

Application of High Tenacity Nylon:

Nylon high tenacity yarn is produced from specially treated polyamide

polymers and is used in tires, for coated fabrics, tarpaulins, as reinforcement

in rubber hoses and conveyor belts, safety belts, ballistic cloth, netting, ropes,

parachutes, racket strings, tents, industrial sewing threads, sleeping bags,

cables and hawsers.

1. SCOPE

This draft Standard specifies requirements for the classification of all

types of High Tenacity Yarn of Nylon or other polyamides for various end

usages.

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2. REFERENCES

The standards given in Appendix contain provisions which, through

reference in this text, constitute provisions of this standard.

3. TERMINOLOGY

This heading lists the technical terms used for high tenacity yarn of

nylon or other polyamides as defined in various test methods /manufacturer’s

booklets.

3.1. Breaking force: The maximum force applied to a test specimen carried

to rupture during a tensile test

3.2. Breaking strength: Term still commonly used, but improperly, for the

average of the results of breaking force measurements.

3.3. Breaking tenacity: The breaking force divided by the linear density of

the unstrained material.

3.4. Breaking toughness: The work required to achieve the breaking force of

the test specimen expressed per unit length and linear density of the

unstrained material.

3.5. Cabled yarn: yarn with two or more components of which at least one is

a folded yarn, combined by one or more twisting operations.

Note: For certain industrial uses the word cord is used for folded or

cabled yarns.

3.6. Elongation: The ratio of the extension of a test specimen to its initial

length, expressed as a percentage.

a) Elongation at break: The elongation of a test specimen produced by

the breaking force.

b) Elongation at rupture: The elongation of a test specimen

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corresponding to rupture.

c) Elongation at specified force: The elongation of a test specimen

produced by a specified force.

d) Elongation at specified tenacity: The elongation of a test specimen

produced by a specified tenacity.

e) Elongation between defined forces: The increase in length of a test

specimen which results from subjecting it to two specified forces.

3.7. Folded yarn: A yarn in which two or more single yarns are combined by

a single twisting operation.

3.8. Industrial Yarn: Yarn intended for use in products other than non-

protective clothing, household, furnishing and floor coverings selected

principally but not exclusively for their performance and properties as

opposed to their aesthetic or decorative characteristics.

3.9. Modulus: The property of a material representative of its resistance to

deformation. In tensile testing the modulus is expressed as the ratio of

tenacity to strain.

3.10. Modulus, wet: The modulus determined when the material is

completely wet. In the definition of the generic name "modal", the term

"wet modulus" is defined as the tenacity required producing an elongation

of 5 % when the specimen is completely immersed in water.

3.11. Moisture content: The amount of water contained in a material,

expressed as a percentage of its total mass (including moisture and any

extractable).

3.12. Shrinkage: The decrease in length of a test specimen caused by a

specified treatment, expressed as a percentage of the length of the

untreated test specimen. The lengths are measured before and during or

after treatment under specified tensions.

a) Boiling water shrinkage: The decrease in length of a test specimen

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caused by a treatment in boiling water for specified time, expressed as

a percentage of the length of the untreated test specimen. The lengths

are measured before and after treatment under a specified pretension.

b) Hot water shrinkage: The decrease in length of a test specimen

caused by a treatment in hot water under a specified temperature and

time, expressed as a percentage of the length of the untreated test

specimen. The lengths are measured before and after treatment under

a specified pretension. The water temperature to be applied is specified

between buyer and seller.

c) Hot air shrinkage, after treatment: The decrease in length of a test

specimen caused by a treatment in hot air under specified temperature

and time, expressed as a percentage of the length of the untreated test

specimen. The lengths are measured before and after treatment under

a specified pretension.

d) Hot air shrinkage, during treatment: The decrease in length of a test

specimen caused by a treatment in hot air under specified temperature

and time, expressed as a percentage of the length of the untreated test

specimen. The lengths are measured before (under a specified

pretension) and during treatment (under a specified measuring tension).

3.13. Strain: The ratio of the extension of a test specimen to its initial length.

3.14. Stress: The resistance to deformation developed within a material

subjected to an external force, expressed as force per cross-sectional

area.

3.15. Tenacity: Force divided by linear density.

3.16. Tenacity at specified elongation: The tenacity associated with a

specified elongation on the tenacity-elongation curve.

3.17. Tensile stress: The force per unit cross-sectional area of the

unstrained specimen.

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3.18. Tensioning force: An abbreviation for tensioning force. In fibres and

yarns the tension applied is usually based on the linear density of the

material.

4. REQUIREMENTS OF HIGH TENACITY YARN OF NYLON OR OTHER

POLYAMIDE

4.1. The High Tenacity Nylon or other poly amide shall meet the

constructional and performance requirements specified in Table- 4.1.

Table- 4.1: Constructional and Performance Requirements of High

Tenacity Nylon or Other Poly-amide

Sl. No.

Characteristic

Requirement

Method of Test

Value CV % Max

Single Yarn

Folded /

Cabled

Single Yarn

Folded /

Cabled

1. Linear Density (Denier) Specified Value

As declared + 2.5 %

Less than or equal to 2%

IS 1226:1957

2. No. of Filaments Specified Value

As declared + 2 Filaments

--- Annex- A

3. Tenacity (cN/tex)) Not less than 60

Not less than 53

Less than or equal to 5% IS 1670:1991

4. Elongation at Break % 25% ± 3

Less than or equal to 8%

5. Hot Air Shrinkage % 10% + 2 Not applicable ASTM D 4974-04

6. Oil Content % Less than or equal to 1.5% IS 3025(-PART 39)

:1991

4.2. Freedom from Yarn Defects - The yarn shall be free from the following

major defects:

4.2.1. Dirt/Grease – No soiling or grease spots shall be allowed. It is

acceptable if the spots can be cleaned off. Air strip yarn to remove dirt

on the outside surface,. For dirt on the ends, clean with sprayer. If dirt

does not come off, reject to off grade.

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4.2.2. Wound in Waste - None allowed. Strip to correct or reject to rewind.

4.2.3. Damaged/bumped – None allowed. Strip to correct or reject to rewind.

4.2.4. Finish oil Contamination – Dry or regular oil yarn shall not be

contaminated with Finish Oil when viewed under a packing table UV

light, unless very slight (not immediately visible). Strip to clean if

possible. Otherwise reject to off-grade.

4.2.5. Broken Filaments – The number of broken filaments shall not be

more than 8 per end for standard package and not more than 10 per

end for large package. The number of broken filaments depends upon

the Denier per filament (DPF)

4.2.6. Fluorescent Oil - If applicable, the package shall have even coverage

under UV light.

4.2.7. Crossed Ends - Nose end crosses can be allowed, unless they

appear matted or too numerous to count. Up to 25 mm crosses on the

tail end are allowed or crosses < 6 mm from the tube shall be allowed.

4.2.8. Slubs/Loops/Kinks - None shall be allowed.

4.2.9. Proper Wind - No patterns or bands, no high or falling off edges and no

excessive hard/soft packages shall be allowed.

4.2.10. Tube Defects - No crushed, nicked, or cut tubes, especially on the nose

end shall be allowed.

4.2.11. Ridges/Grooves – No ridges or grooves > 3mm high or deep shall be

allowed.

4.2.12. Twist – For single ply yarns only, Z twist shall rotate clockwise when

allowed to relax and S twist rotates counter-clockwise.

4.2.13. Proper Ply – Count the number of ends if the yarn is three ply or more.

Air strip the yarn to correct if possible. Also check the tail.

4.2.14. Latching – Filaments or plies that separate when winding off package

shall not be allowed.

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4.2.15. No Tail – Only one tail package per layer shall be permitted. The

minimum tail length shall be one wrap around the tube. If tail is too

short, take a short length of yarn and tie it on to the tail. For parallel yarn

smalls and no tails are allowed.

4.2.16. Multiple Tails – If there are multiple tails, then correct if possible or

reject to rewind.

4.2.17. Tube Clearance – It shall be 9 mm, Min from yarn roll to tail end of tube

and 25 mm Max ( nominal should be 15 mm)

4.2.18. Oversize or Small Package – Check suspect packages with

appropriate gauge, scale, diameter tape, or balance. Do not put

excessive minimum size packages in one case.

5. SAMPLING AND CRITERIA FOR CONFORMITY

5.1. Lot: The number of cartons of High Tenacity Nylon or other Polyamide of

the same type and designation delivered to a buyer against one dispatch

note shall constitute a lot. The number of cartons of High Tenacity Nylon

or other Polyamide to be selected at random from a lot shall be according

to col 2 of Table- 5.1. From each carton one cheese shall be selected at

random to constitute the sample size. To ensure the randomness of

selection, IS 4905 may be followed.

5.2. Number of Tests and Criteria for Conformity: The number of cheeses

to be selected for manufacturing defects shall be in accordance with col 2

of Table-5.1. For linear density, number of filaments, elongation, tenacity,

and commercial mass, etc.., the number of cheeses selected shall be in

accordance with col 4 of Table- 5.1. For all other properties, the number

of cheeses selected shall be in accordance with col 5 of Table-5.1.

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TABLE-5.1. SAMPLE SIZE

All the cheeses selected for requirements shall be tested for those

requirements as specified in Table-4.1. All the selected cheeses from the lot

shall be visually examined for yarn defects as specified in sub heading 4.2. A

cheese shall be declared defective if it contains at least four yarn defects or it

does not meet any of the requirements specified in this standard. The lot shall

be declared conforming to the requirements of this standard if the total

number of defective cheeses does not exceed the value given in col 3 of

Table-5.1.

1 2 3 4 5

Lot Size,

Number of

cartons of

HT PA

Sample

Size,

Number

of

cartons

Permissible

Number of

Non-

conforming

cheeses

Sub-sample

Size

Sub-sub-

sample Size

Up to 50 5 0 3 2

51 – 150 8 0 5 3

151 – 300 13 1 5 3

301 – 500 20 1 8 5

501 – 1000 48 3 10 7

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5.3. Declaration of Results:

Table- 5.2 Declaration of Results:

Sl.

No. Characteristic

Observed Accepted Accept

able or

Not

Single

Yarn

Folded /

Cabled

Single

Yarn

Folded /

Cabled

1.

Linear Density (Denier)

Specified Value

CV %

2.

No. of Filaments

Specified Value

CV %

3 Tenacity (gpd)

CV %

4 Elongation at Break %

CV %

5 Hot Air Shrinkage %

CV %

6 Oil Content %

CV %

Result: The above yarn qualifies / does not qualify as High Tenacity Yarn.

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APPENDIX

LIST OF REFERRED STANDARDS

STD No Title

IS 6239:1971 Generic names for Manmade Fibres.

IS 4905:1968 Methods for random sampling

IS 7867:1975 Continuous filament textile polyamide (nylon) yarn

IS 7703-1:1990 Methods of Test for Continuous Filament polyester filament

polyester and polyamide flat yarn, Part 1: Linear Density.

IS 7703-2:1990 Methods of Test for continuous filament polyester and polyamide

flat yarn, Part 2: Tenacity and Elongation at break.

IS 7703-4:1981 Methods for Test for Continuous Filament Polyester and Polyamide

Flat Yarn, Part 4: Sampling

IS 0686:1985 Methods for determination of colour fastness of textile materials to

daylight (first revision)

IS 0766:1988 Method for determination of colour fastness of textile materials to

rubbing (first revision)

IS 3456:1966 Method for determination of water soluble matter of textile materials

IS 6590:1972 Specification for braided nylon ropes for mountaineering purposes

IS 9936:1992 Manila, nylon, polyester and polypropylene ropes for marine

purpose - Guide on equivalence (first revision)

IS 4401:2006 Textiles-Twisted nylon fishnet twines (fifth revision)

IS 7533:2003 Textiles - Polyamide (nylon) monofilament line for fishing -

Specification (first revision)

IS 7703:1987 Methods of test for continuous filament polyester and polyamide flat

yarn Unevenness percentage (Part 5)

IS 14563:1998 Textiles- Determination of formaldehyde Part 1 Free formaldehyde

(Part 1

IS 15570:2005 Textiles- Method of test- Detection of banned azo colourants in

coloured textiles

IS 15651:2006 Textiles – Requirements for environmental labelling – Specification

ASTM D4974-04 Standard Test Method for Hot Air Thermal Shrinkage of Yarn and

Cord Using a Thermal Shrinkage Oven

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ANNEX - A

METHODS FOR DETERMINATION OF NUMBEFR OF FILAMENTS

A-1 APPARATUS

Microscope

Microscopic Slides

Glycerol / Water

Cutter & Measuring Scale

A-2 PRINCIPLE

The specimens in the form of filament yarn are cuttings from different

places so as to cover the entire surface in each direction/different cones.

Mount those specimens on the microscopic slides using glycerol / Water.

A-3 PROCEDURE

Take 5 specimens of yarn cuttings from separated different places so as

to cover the entire surface in each direction/different cones.

Mount the specimens on the microscopic slides using glycerol and

tease the strands so as to achieve maximum separation of all individual

filaments.

Mount the slides on the microscope.

Count the individual no of filaments visually.

Note down the no of filaments on the work sheet.

Repeat the same process for all the specimens.

Then report the No of filaments average of five readings as the direction

wise incase of fabric.