AATCC 98:2016 pdf download.Alkali in Bleach Baths Containing Hydrogen Peroxide
1. Purpose and Scope
1.1 This test method determines the total alkali content of a bleach bath containing hydrogen peroxide and alkali from any source. The total alkali content is expressed as % sodium hydroxide.
1.2 Alkali in bleach baths may be supplied by sodium hydroxide. sodium silicate. sodium carbonate or by various other alkaline materials. including potassium compounds. ammonia, lime or by peroxygen solids which contain alkaline salts.
1.3 The alkali content of a bleach bath is a critical parameter in determining the rate and extent of bleaching and may also determine the extent to which the textile being bleached is affected by the bleaching process.
1.4 This test method is used for laboratory determinations and for process control.
2. Principle
2.1 A weighed specimen of the bleach bath is titrated with a siandardited solulion of sulfuric acid to a Phenol Red endpoint, or to the pH range 6.8-8.4 on a pH meter. The total alkali, expressed as % NaOH, is calculated based on the weight of the bath.
3. Terminology
3.1 bleaching, n.—eliminat ion of unwanted coloring matter from a substrate by oxidative or reductive chemical treatment.
4. Safety Precautions
NOTE: These safiiy precautions are for information purposes only. The safety precautions are ancillary to the testing procedures and arc not intended to be all inclusive. It is the user’s responsibility to use safe and proper techniques in handling materials in this test method.. Manufacturers MUST be consulted for specific details such as material safety data sheets and other nianuflicturer ‘s recommendations. All OSHA standards and rules must also he consulted and followed.
4.1 Good laboratory practices should be followed. Wear safety glasses in all laboratory areas.
4.2 All chemicals should be handled ‘jth care. Sulfuric acid is corrosive. When preparing the dilute solutions from pure or concentrated reagents, use chemical goggles or face shield, impervious gloves, and an impervious apron. CAUTION: Always add acid to water.
4.3 An eyewash/safety shower should he located nearby and a high efficiency particulate respirator with organic vapor cartridge and full facepiece should he readily available for emergency use.
4.4 Exposure to chemicals used in this procedure must be controlled at or below levels set by governmental authorities (e.g., Occupational Safety and Health Administration’s IOSHAI permissible exposure limits IPELI as found in 29 (‘FR 1910. I (XX); see web site: www.osha.gov
11w latest version). In addition, the American Conl1rence of Governmental Industrial Hygienists (ACG I H) Threshold Limit Values (TLVs) comprised of time weighted averages (TLV-TWA), short term exposure limits (TLV-STEL) and ceiling limits (TLV-C) are recommended as a general guide for air contaminant exposure which should be met (see 10.1).AATCC 98 pdf download.