Waterproof terminology: hydrostatic pressure, air permeability, water repellency, moisture permeability

1. Water Proofness (WP):

1 Introduction

WaterProofness: The outdoor fabric industry is accustomed to call it water pressure resistance. The unit is expressed in mmH2O, which refers to the strength of water pressure per unit area. Under standard laboratory conditions, the fabric is subjected to the pressure of distilled water sprayed upward, and the maximum water pressure is recorded. For example, the water pressure resistance is 5000mmH2O, that is, the unit area can withstand a maximum pressure of 5m without leakage.

2. Commonly used test standards

American Standard AATCC 127;

Japanese standard JIS L1092B;

European standard: IS0 811;

3. Test method:

The water pressure test is divided into two methods: before and after washing:

Test before washing: Domestic outdoor brands generally test the water pressure resistance value before washing, but not after washing. If the water pressure resistance value drops greatly after several washings, it may drop by about 1000-3000mmH2O;

Test after washing: foreign famous outdoor brands generally test the water pressure after 5 times of washing. THENORTHFACE even adopts the method of measuring the water pressure after 20 times of washing. Due to the test after multiple washings, the water pressure value drops greatly. Such a test The method is that any coating factory or film laminating factory must use better materials for processing. For example, the water pressure resistance of coated fabrics requires 5000mmH2O after 5 washings, then at least 7-8000mmH2O before washing; of course, this requirement will lead to The price is higher!

2. Method Air Permeability (MAP):

1 Introduction:

Method Air Permeability: means the performance of air passing through the fabric; under the specified differential pressure conditions, measure the air flow rate vertically passing through a given area of the sample within a certain period of time, and calculate the air permeability. The airflow rate can be measured directly, or it can be converted by measuring the pressure cars on both sides of the flow aperture.

2. Test standard:

American Standard ASTM D737

European standard ISO 9237

Japanese standard JIS L1096;

The ventilation unit can be expressed in mm/s or cm3/cm2/s;

3. Anti-splashing water:

1 Introduction:

Under the standard laboratory, use distilled water to spray on the sample through a funnel, and score and grade against the waterproof standard sample.

2. Test standard:

American Standard: AATCC 22;

European standard: ISO 4920;

3. There are three kinds of anti-splashing water:

Ordinary waterproof (WaterRepellent, abbreviated as: W/R), water repellent (DurableWaterRepellent outdoor fabric industry is used to call super water repellent, abbreviated as: DWR), Teflon (TEFLON) waterproof;

Ordinary waterproof (W/R): The surface of the clothes is not waterproof after washing a few times. Generally, ordinary waterproofing is enough for outdoor leisure. If you often go to mountain climbing or mountains with a certain altitude, the weather on the mountain is fickle, and it may rain at any time. Ordinary waterproof clothing is not waterproof after washing several times, causing the surface of the clothing to be wet, and wearing it will increase the weight of the human body.

Super water-repellent (DWR): Japan's Daikin carbon 6 waterproof, after 20 washes to maintain the effect of 80 points (European standard 3); the previous carbon 8 waterproof, after 30 washes can reach 80 points, due to the fluorine content The amount does not meet EU standards and is now banned by the EU.

Teflon (TEFLON), produced by DuPont in the United States, has a very high reputation, and has three anti-fouling effects such as waterproof, anti-fouling, and oil-proof. The water-repellent effect is not as good as that of carbon 8 and carbon 6;

4. Moisture permeability (MP):

1 Introduction:

Moisture Proofness (abbreviated as MP), expressed in units of g/m2/24h, means that under certain standard laboratory conditions, a specific humidity difference is formed on both sides of the sample, and water vapor enters through the sample. On the dry side, parameters such as the water vapor transmission rate of the sample can be obtained by measuring the change in the weight of the moisture permeable cup over time.

2. Test standard and test method:

There are two test methods for moisture permeability: positive cup and inverted cup;

Positive cup method: American standard ASTM E96 A, C, E; Japanese standard JIS L1099 A1;

Inverted cup method: American standard ASTM-E96, Japanese standard test JIS L1099B1;

This test uses pre-wash data!

Fifth, the difference between moisture permeability and breathability:

Both domestic outdoor practitioners and outdoor enthusiasts refer to moisture permeability as breathable and moisture-permeable, or directly call moisture-permeability as breathable. It is incorrect and imprecise to confuse these two terms. This is a concept that needs to be distinguished and correctly understood; fabrics with three functional indicators of water repellency, moisture permeability and breathability are called waterproof and moisture-permeable fabrics, also known as wind-proof, waterproof, warm and moisture-permeable fabrics. Come on, the sweat inside drains out through the pores of the coating and membrane!