GB/T 19390-2023Dipped polyester cord fabric for tyres (English PDF)

Foreword

This document was issued on 17 March 2023 by the State Administration for Market Regulation; Standardization Administration of the PRC and takes effect on 1 October 2023.

It is a GB/T standard: recommended rather than compulsory, but it is the text a Chinese reviewer applies when assessing a submission.

1 Scope

GB/T 19390-2023 covers the dipped polyester cord fabric that reinforces a tyre carcass — the product classification and specifications, the technical requirements, and the methods by which the fabric is tested and accepted. The classification separates high-modulus low-shrinkage fabric from the high-strength and the high-dimensionally-stable grades, so that a tyre maker orders by property rather than by supplier name. The requirements clause covers the physical and chemical properties together with the appearance indicators, judged roll by roll. Test conditions, product batching and specimen preparation are fixed before the methods themselves, because tensile results on a textile move with the atmosphere the specimen sat in and with the way the cord was gripped; the physical and chemical methods then run from the tensile test to the H-test adhesive strength, which is what shows whether the cord will hold its bond to the surrounding rubber. Inspection of tissue specifications and appearance quality, the inspection rules, and the packaging, marking, quality guarantee, transport and storage clauses close the document, with informative annexes on the CRT tensile machine method and on pneumatic grips. Cord that loses strength or shrinks unevenly leaves a tyre that grows out of shape or separates in service. Written for cord fabric producers, tyre manufacturers, and their incoming inspection laboratories.

This document specifies product classification and specifications, technical

requirements, test conditions, regulations on product batching and specimen

preparation methods, physical and chemical properties test methods, tissue

specifications and appearance quality inspection methods, inspection rules as well as

packaging, marking, quality guarantee, transportation and storage FOR dipped

polyester cord fabric for tyres.

This document is applicable to the identification and acceptance of the quality of dipped

polyester cord fabric for tyres.

2 Normative references

The following referenced documents are indispensable for the application of this

document. For dated references, only the edition cited applies. For undated references,

the latest edition of the referenced document (including any amendments) applies.

GB/T 2942-2009, Rubber, vulcanized - Determination of static adhesion to textile

cord - H-pull test

GB/T 3291 (all parts), Textiles - Terms of textile material properties and test

GB/T 4666-2009, Textiles - Fabrics - Determination of width and length

GB/T 4668-1995, Textiles - Woven fabrics - Determination of number of threads per

unit length

3 Terms and definitions

For the purposes of this document, the terms and definitions defined in GB/T 3291 (all

parts) as well as the followings apply.

3.1 H-test adhesive strength

The force required to pull the cord from the H-shaped rubber-cord test piece in the

direction perpendicular to the rubber block per unit length.

3.2 dip pick-up

The dipping component of the dipped cord is separated from the white cord by chemical

method and dried to a constant weight. The ratio of the constant mass of the

impregnated substance to the constant mass of the blank cord shall be the dip pick-up.

3.5 warp density within specified width from each edge

The number of warp threads within a certain length from both sides of the cord fabric

to the cloth edge.

3.6 net weight

The mass of dipped cord fabric obtained by subtracting the mass of all packaging

materials from the mass of the cord fabric roll when leaving the dipping machine.

4 Product classification and specifications

4.1 According to physical and chemical properties, dipped polyester cord fabrics are

divided into high-modulus low-shrinkage (HMLS), high-strength high-modulus low-

shrinkage (HTHMLS) and high-dimensionally-stable high-modulus low-shrinkage

(HDS-HMLS).

4.3 Each specification of dipped polyester cord fabric can be divided into various

specifications according to the warp density. Commonly used dipped polyester cord

fabric has 15 specifications, see Table 1.

5 Technical requirements

5.1 Physical and chemical properties

5.2 Appearance indicators

5.2.1 The appearance quality of dipped polyester cord fabric is evaluated in units of

rolls. The length of each roll of dipped polyester cord fabric is calculated as 1080 m.

6 Test conditions, regulations on product batching and specimen

preparation methods

6.1 Test conditions

6.2 Regulations on product batching and specimen preparation methods

6.2.1 Take several roll cord fabrics produced from the same warp bobbin as a batch of

goods. However, if they are produced by different processes or are not continuously

Cord specifications

6.2.3 From 20 cm away from the edge of the test cloth, uniformly extract cords with a

length of 500 mm ~ 600 mm from 6 positions equidistant from each other. Remove the

weft. After mixing, it is used as the specimen of this batch of dipped polyester cord

fabric.

6.2.4 In the event of disputes between the supplier and the buyer over the test results,

the test results jointly accepted by randomly selected specimens shall prevail.

7 Test methods for physical and chemical properties

7.1 Tensile property test

7.1.1 Principle

Under the specified conditions, clamp the cord specimen between the two clamps of

the CRE electronic tensile testing machine. Stretch the specimen to fracture at the

specified tensile speed. Determine the breaking strength, constant load elongation and

breaking elongation of the specimen directly from the strength-elongation curve or data

display.

7.1.2 Test instruments

This document recommends using CRE tensile testing machine. See Annex A when

using a CRT tensile testing machine. In case of any dispute over the tensile test results,

the test results of the CRE tensile testing machine shall prevail.

7.1.3 Number of specimens

It shall be ensured that the number of effective specimens is 20.

7.1.4 Test conditions

Distance between the jaws of the upper and lower fixtures. (250+/-1) mm.

Tensile speed. (300+/-5) mm/min.

7.1.5 Operating procedures

7.1.6 Calculation

Use a testing machine that is not equipped with an automatic test data processing device.

From the stress-strain curve of the specimen, read and record the breaking strength,

breaking elongation and constant load elongation of each specimen.

7.2 H-test adhesive strength test

According to the provisions of GB/T 2942-2009.The test conditions therein are as

follows.

7.3 Dip pick-up test

7.3.1 Principle

Because the mixed solvent in 7.3.4.1 can only dissolve polyester fiber, but not rubber

compound, separate the dipped film on the dipped cord with a measured constant mass

from the blank cord. Measure the constant mass of the dipped film. The ratio of the

constant mass to the constant mass of the blank cord shall be the dip pick-up of the

dipped cord.

7.3.5 Calculation

Use formula (4) to respectively calculate the dip pick-up of two specimens. Use the

arithmetic mean to represent the dip pick-up of each batch of cords. The value of the

calculation result shall be rounded to one digit after the decimal point according to

GB/T 8170.

7.4 Hot air thermal shrinkage test

7.4.1 Test method of hot air thermal shrinker

7.4.1.3 Number of specimens

It shall be ensured that the number of effective specimens is 5.

7.4.1.4 Test conditions

Temperature. (177+/-2) degrees C. Heat treatment time. 2 min.

7.7.6 Precautions

7.7.6.1 The calculation result shall indicate the off-machine moisture regain or moisture

regain after unpacking.

7.7.6.2 In order to prevent the moisture regain of the specimen from changing during

the test, the operator shall wear cotton gauze gloves on both hands. Place the specimen

in a dry, airtight container. Weigh it as soon as possible.

8 Inspection methods for tissue specifications and appearance quality

8.1 Inspection method for tissue specifications

8.1.1 Inspection method for cloth roll length

It is carried out in the way of metering on-line in the dipping production line

(manufacturer) or calendering production line (user). The unit is m. The value of the

inspection result shall be rounded to an integer according to GB/T 8170.

8.1.4 Inspection method for weft thread density

According to the provisions on the single piece method in GB/T 14343-2008.The unit

is dtex. The value of the inspection result shall be rounded to an integer according to

GB/T 8170.

9 Inspection rules

9.1 The physical and chemical properties indicators are sampling inspections. The

sampling methods shall be carried out according to the regulations in 6.2.1 and 6.2.2.

9.2 Appearance indicators are all inspections. The inspection items in Table 6 are all

assessment items. Carry out inspection according to the inspection method specified in

8.2.If there is one item failure, the product shall be rejected.

9.3 The buyer can inspect the product provided by the manufacturer according to the

provisions of this Standard within 12 months after the product is dipped. If the

inspection is not carried out within the time limit, it is deemed that the buyer has

approved the inspection results indicated in the quality guarantee issued by the seller.

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