GOST 23785.7-89 PDF

Full title and description

GOST 23785.7-89 — "Cord fabric. Method for determination of resistance to rubber adhesion" (Russian: "Ткань кордная. Метод определения прочности связи с резиной"). The standard specifies a laboratory method to determine the strength of adhesion between the basic impregnated warp (cord) threads of cord fabric and rubber by measuring the force required to pull a cord yarn out of a vulcanized rubber block.

Abstract

This standard defines preparation of rubber‑cord test specimens, impregnation and vulcanization procedures, test-fixture and specimen geometry, tensile test speed and result processing to obtain the average pull‑out force (characterizing adhesion of cord threads to rubber). It is intended for cord fabrics produced with chemical-fiber warps and supplies repeatable laboratory procedures for quality control and specification verification.

General information

• Status: Active (in force / действует).
• Publication date: Effective from 01 January 1991 (designation year 1989: GOST 23785.7-89).
• Publisher: Interstate standard (Межгосударственный стандарт) / Gosstandart (USSR origin; later maintained in national collections).
• ICS / categories: Textile and leather production — OKC/ICS code 59.080.30 (textile products / testing methods).
• Edition / version: Designation GOST 23785.7-89; replaces GOST 23785.7-79; includes at least Amendment No.1 (issued Dec 1991) and a reprint with changes in 1996.
• Number of pages: 19 pages (typical published text length).

Scope

The standard applies to cord fabric manufactured with chemical-fibre warps and establishes the laboratory method for determining the adhesion strength of the main impregnated warp (cord) yarns to rubber. Adhesion is characterized by the pull‑out force of a cord yarn vulcanized into a rubber block; the procedure specifies specimen preparation, impregnation, vulcanization, conditioning, test execution and result processing.

Key topics and requirements

• Specimen preparation: production of rubber‑cord test plates with specified mold sizes and positioning of yarns for vulcanization.
• Impregnation: preparation and application of specified impregnation compositions for the cord yarns (including optional resorcinol‑formaldehyde systems where referenced).
• Vulcanization conditions: typical vulcanization at (138 ± 2) °C for 45 minutes (alternative: 155 ± 2 °C for 30 minutes) and defined cooling/conditioning before testing.
• Number of test specimens: specified minimum counts (for example, 15 specimens for polyamide yarns and 10 for viscose yarns) to obtain statistically meaningful averages.
• Test method: tensile testing on a universal testing machine at a crosshead speed of (100 ± 10) mm/min; measurement of maximum pull‑out force in newtons or kilograms-force.
• Result processing: arithmetic mean of individual specimen results (rounded to 1 N) and rules for handling outliers or test discrepancies.
• Equipment and fixtures: specified holder and mold dimensions, impregnation frames and handling precautions to avoid damage to test yarns.

Typical use and users

Primary users are cord‑fabric manufacturers, tire and rubber goods producers, independent test laboratories, quality control and R&D departments that need to verify or specify the adhesion performance of cord fabrics intended for reinforcement of rubber products. Certification bodies and technical procurement teams also use the method to confirm compliance with product specifications.

Related standards

This method is part of the GOST series on cord fabrics and testing; it replaces GOST 23785.7-79 and references other related GOST documents and test methods (for example, parts/related items in the GOST 23785 series and GOSTs cited within its normative references). Reissues and amendments (Amendment No.1, 1991; reprint 1996) are recorded in national catalogs.

Keywords

cord fabric, cord cloth, cord yarn, rubber adhesion, pull‑out test, vulcanization, impregnation, tensile test, GOST 23785.7-89, cord‑to‑rubber bond.

FAQ

Q: What is this standard?

A: GOST 23785.7-89 is a test method standard that specifies how to determine the strength of the bond (adhesion) between cord fabric warp yarns and rubber by measuring the force required to pull a yarn out of a vulcanized rubber block.

Q: What does it cover?

A: It covers sample preparation (impregnation and mold assembly), vulcanization regimes, specimen conditioning, tensile testing speed and fixtures, calculation and reporting of the average pull‑out force and related test details required for consistent laboratory results.

Q: Who typically uses it?

A: Cord fabric and tire/rubber product manufacturers, materials and quality laboratories, R&D groups working on reinforcement materials, and conformity assessment bodies that verify adhesion performance.

Q: Is it current or superseded?

A: The standard is listed as active/in force (the limitation of validity was removed by the relevant Gosstandart resolution); it replaced the earlier GOST 23785.7-79 and has recorded amendments (Amendment No.1, Dec 1991) and later reprints. Users should check national catalogues or official libraries for the latest status or any newer replacements.

Q: Is it part of a series?

A: Yes — it is one part in the set of GOST documents and subparts covering cord fabrics and related test methods (parts and related GOSTs are cited within its normative references).

Q: What are the key keywords?

A: Cord fabric, adhesion to rubber, pull‑out strength, vulcanization, impregnation, tensile testing, GOST 23785 series.