ISO 4900:2011

Overview

ISO 4900:2011 specifies a laboratory test method for determining the contact mouldability of textile glass mats and fabrics used in composite hand lay-up processes. The standard defines the mould geometry, specimen preparation, resin system, timing limits and how to record and report the radius at which a reinforcement will no longer conform to a stepped mould. ISO 4900:2011 is intended for objective comparison of mats and fabrics when the hand lay-up process is carried out consistently by the same operator.

Key topics and requirements

• Scope: Test method for textile glass mats and fabrics - contact mouldability under hand lay-up conditions.
• Specimen dimensions: Rectangular strips, 950 mm ± 10 mm long and 150 mm ± 2 mm wide. Test three specimens cut parallel and three cut perpendicular to fabric length.
• Conditioning: Specimens conditioned for at least 6 hours in a standard atmosphere per ISO 291; tests performed under the same conditions.
• Mould: A glass-fibre-reinforced plastic step/radius mould with progressively decreasing radii marked at each ridge.
• Resin system: A standard hand-layup polyester resin (user/supplier to agree), incorporating methyl ethyl ketone peroxide (MEKP) catalyst and cobalt naphthenate accelerator to give a pot life ≈ 30 minutes at test temperature.
• Equipment: Balance (0.1 g), stopwatch, 50 mm brush, sharp knife, mould release, scraper and solvents.
• Procedure highlights:
  • Apply thin resin coat, lay specimen on mould, work the material with the brush into successive corrugations, record the working time (max 5 min).
  • Note the ridge at which the specimen no longer conforms; record mouldability as the previous (less severe) radius.
  • Weigh specimen before and after to determine reinforcement and resin masses.
• Results:
  • Report average mouldability radius for the three parallel and three perpendicular specimens (nearest 1 mm).
  • Calculate the reinforcement-to-resin mass ratio (R) for each laminate and report averages (one decimal).
• Reporting: Include standard reference, material and resin descriptions, resin formulation and viscosity, individual and average mouldability values, working time, reinforcement/resin ratios, test date and any deviations.

Applications and users

• Quality control and incoming inspection for textile glass mats and fabrics used in marine, automotive, wind energy and general composite manufacturing.
• Product development and comparative evaluation of reinforcements for hand lay-up moulding.
• Test laboratories, material suppliers, composite manufacturers, and specification writers who need objective data on how easily a reinforcement will conform to contoured moulds.

Related standards

• ISO 291 - standard atmospheres for conditioning and testing (referenced for specimen conditioning).

Keywords: ISO 4900:2011, contact mouldability, textile glass, mats and fabrics, radius mould, hand lay-up, reinforcement-to-resin ratio, working time, composite quality control.