Everything you need to know about perspiration resistance

What is perspiration fastness?

Perspiration fastness is the degree of color retention of textiles in perspiration, which is particularly important for apparel products.

With daily use, the textile stays in close contact with the skin for a long time. At the same time, contact with the sweat secreted by the skin has a major impact on some dyes, causing them to be transferred from the textile to the skin. Some of the dyes on textiles are not acid resistant and some are not alkali resistant. Therefore, during the testing process, it is necessary to prepare acid-alkali artificial sweat to simulate the human body's acid-base sweatrs. And test the textiles at 37°C to simulate human body temperature, mainly for textiles that come in contact with the skin.

The standard for perspiration fastness

The common test standards for perspiration fastness at present include mainly : Tests for colour. Fastness of textiles Part E04: Color fastness to perspiration” (ISO 105-E04:2008); Color Fastness to Sweat (AATCC 15: 2009).

AATCC 15 Tests of Color Fastness to Acid Sweat. ISO 105 E04 goes one step further and tests color fastness to acidic and alkaline sweat.

Human sweat is normally acidic. However, at higher temperatures or in the presence of bacteria, it becomes alkaline. So the ISO standard goes further In this case thorough.

Determination of color fastness to perspiration (BS EN ISO 105-E04) Overview

Scope: Applies to testing the color fastness of various textiles to perspiration.

pPrinciple: The textile sample is combined with the given adjacent fabric and placed in two different test solutions containing histidine. After the separate treatment, remove the test solution and place it between two flat plates with the specified pressure in the test device. Place the specified time under the specified temperature conditions, and then dry the sample and the adjacent fabric separately. Use the gray scale or instrument to assess sample discoloration and adjacent fabric discoloration.

Equipment and Materials

Test Equipment: including a stainless steel frame; Weight weighing 5 kg and a base area of ​​11.5 cm x 6 cm, fixed with a glass plate or acrylic resin plate of the same size and 0.15 cm thick. The combined sample must be 10cm x 4cm to ensure the sample is pressurized to 12.5kPa.

Thermostat: Keep warm at 37±2°C.

Reagent:1) . L- histidine hydrochloride monohydrate2) sodium chloride3) disodium hydrogen phosphate dodecahydrate or disodium hydrogen phosphate dihydrate4) . Sodium hydrogen phosphate dihydrate5) ) . Sodium Hydroxide

Backing: Use one piece of multifilament backing or two pieces of monofilament backing.

Gray scale to assess discoloration and staining.

Sample Preparation Fabric

If the sample is fabric, prepare the sample using one of the following methods:

a) Take a piece of (40 ± 2) mm × (100 ± 2) mm sample, the front side is in contact with a piece of (40 ± 2) mm × (100 ± 2) mm multi-fiber lining and sewn along a seam on the short side, forming a combined Sample.

b) Take a piece of (40 ± 2) mm × (100 ± 2) mm sample, put it between two pieces of monofilament lining and sew es along a short side to form a combined pattern. When testing printed fabrics, the front of the fabric touches half of each of the two adjacent fabrics, cuts off the other half and crosses them on the back (e.g. if the two adjacent fabrics are silk and cotton. Cut half of the silk and Cotton off and(front side of the fabric. One end is in contact with the silk and the same end on the opposite side is in contact with the cotton.) If one sample cannot cover all colors, multiple combined samples are required to cover all colors.

Yarn

If the sample is yarn, it is woven into one fabric with an amount of yarn equal to half the weight of the two adjacent fabrics, or a thin layer is formed in parallel lengths , which is sandwiched between two monofilament linings Or between a piece of multifiber lining and a piece of undyed fabricff of the same size, the four sides are sewn and the yarns are fixed to form a combined sample. Two composite samples are required for the entire test.Fiber

If the sample is loose fibers, the amount is about half the weight of the two adjacent fabrics, and they are combined and divided into (40 ± 2) mm × (100 ± 2) mm thin discs pressed and sandwiched between two single fiber bonds. between linings. Or between a piece of multifiber lining and a piece of non-dyed fabric of the same size, between the lining fabric, sew along the four sides to fix the fibers and form a combined sample. Two compound types are required for the entire test.

Preparation of test solution

Preparation of test Distilled water solution: Prepare and use immediately.

Caustic

Contains per litre:

L-histidine hydrochloride monohydrate 0.5 g

Sodium chloride 5g

Disodium hydrogen phosphate dodecahydrate 5 g or

Disodium hydrogen phosphate dihydrate 2.5 g

Adjust the pH of the test solution to 0.1 mol/L to (8±0.2) a sodium hydroxide solution

acid

Contains per liter:

L-histidine hydrochloride monohydrate 0.5 g

Sodium chloride 5 g

Sodium dihydrogen phosphate dihydrate 2.2 g

Use 0.1 mol/L sodium hydroxide solution to adjust the pH of the test solution (5.5 ± 0.2)

Test procedure

1 First, weigh the weight of the combined sample and calculate the volume of the required solution according to the bath rate of a 50ml solution: 1 gram sample, measure the required amount of acid and alkali test solution with a graduated cylinder, pour them into the container, and then put them in one piece. Assemble the samples, allow them to wet completely, and allow to dry for 30 minutes at room temperature. If necessary, press lightly and shake to sicensure that the test solution can penetrate well and evenly. Take out the sample and weigh the sample again to ensure that the weight after soaking is 2~2.5 times the initial weight. The sample is placed between two sample plates and placed on the sweat tester. Then the weight is put on it, and then the screws are tightened to fix the position. In this way the sample is subjected to a pressure of 12.5 kPa. Then the weight is removed and other combined samples are placed in the same way. The equipment used for alkali and acid testing should be separated.

2. Put the two sets of acid and alkali instruments together. Constant temperature samples Keep the test device in the box, hold it vertically and place it at a temperature of 37 ± 2 °C for 4 hours.

3 Remove all but one short side of the combined sample, unfold the combined sample and hang to air dry at a temperature not exceeding 60 °C.

4 Use the gray scale chart or instrument to measure the deformation of each sample and Evaluate staining on the side of the adjacent fabric Contact with the sample.

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