加载中…
个人资料
  • 博客等级:
  • 博客积分:
  • 博客访问:
  • 关注人气:
  • 获赠金笔:0支
  • 赠出金笔:0支
  • 荣誉徽章:
正文 字体大小:

如何区别Waterproof\Water Repellent\Water Resistant\Weather Resistant

(2014-06-04 11:43:10)
标签:

特种纺织

卓诚纺织

nfpa2112

astmf

Fabrics and garments may be labeled waterproof, water-repellent, weather-resistant or some combination of these. But what does it all mean?

Waterproof
A waterproof fabric is completely impermeable to water.(1) Since all the pores are closed, these fabrics are also impermeable to air and can become hot and uncomfortable as apparel. A vinyl raincoat is an example of a waterproof garment. The wearer remains dry since rain stays outside the coat; it can not soak into or through the fabric. Waterproofness is easy to determine either water can get in or it can not.


Water Repellent
Water repellence and water resistance introduce a lot more uncertainty. Water repellency is the resistance to wetting; water resistance is the resistance to wetting and water penetration.(2) Different fabrics resist wetting (absorbing water) to different degrees and the AATCC Technical Manual includes two methods for determining water repellency. AATCC Test Method (TM) 22, Water Repellency: Spray Test calls for a visual evaluation of the wetting pattern after the fabric is sprayed with water. Manufacturers and retailers must agree on an acceptable level of repellency based on the end-use of each fabric. A rating of 80-90 (on a scale of 0-100) is generally acceptable for unlaundered samples intended for use as water-repellent outerwear.(3) Water repellency tests measure the amount of water that soaks into the fabric, not the amount that soaks through.

Intended mainly to measure the water-repellent efficacy of finishes, TM 70, Water Repellency, Tumble Jar Dynamic Absorption Test is not intended to predict rain penetration resistance.(4) Specimens are tumbled in water, weighed, and the wet weight is compared to the dry weight.


Water Resistant
AATCC TM 35, Water Resistance: Rain Test and TM 42, Water Resistance: Impact Penetration Test use the weight of the water penetrating the fabric as a measure of resistance. Less than 1 g is usually considered acceptable;3 anything over 5 g is reported as > 5 g and indicates failure as a water-resistant fabric.2 The rain test may be performed at different pressures to simulate different intensities of rain and acceptable values for both tests may vary according to end-use.

Another measure of water resistance is TM 127, Water Resistance: Hydrostatic Pressure Test. Water is directed at one side of the fabric under increasing pressure and the point at which water droplets appear on the opposite side is recorded. This test differentiates between the water resistance of the fabric and the water repellency of the fiber, yarn, and fabric construction. The degree to which the fibers and yarns resist wetting, combined with the size, shape, and number of pores in the fabric construction, influences the overall penetrability of the fabric.(5)


Weather Resistant
Weather resistance, the ability of a material to resist degradation of its properties when exposed to climactic conditions,6 is an even more complicated issue. AATCC TM 186, Weather Resistance: UV Light and Moisture Exposure subjects fabrics to artificial weathering through the use of ultraviolet (UV) light, humidity, and/or water spray. Exposed fabrics are compared to control fabrics in terms of color change and breaking or bursting strength. This test is most appropriate for items which will be placed outdoors for extended periods of time. The test method suggests three cycle options based on end-use梘eneral applications (e.g., outdoor furniture fabrics, and tent material), architectural applications where thermal shock may be an issue, and automotive exteriors. The UV and humidity/spray conditions for each application vary slightly. TMs 111, 169, and 192 are similar tests, using different combinations of light and/or water to simulate weathering.
So, will your fabric keep you dry?


Waterproof fabric will protect you from rain, but will eventually make you hot and sweaty. A water-repellent fabric will probably keep you dry if you are out in the rain for just a few minutes. Water-resistant fabrics may also keep you dry temporarily and they will be more breathable than waterproof fabrics, but water will eventually soak in, making the fabric heavy and wet. While a weather-resistant fabric makes no promise to keep you dry, it will continue to look and perform as it was intended even after prolonged exposure to sun and rain.

 

References
1. Dictionary of Fiber & Textile Technology, KoSa, Charlotte, N.C., U.S.A., 1999, p215.
2. AATCC Technical Manual, Vol. 81, 2006, pp65-67, 85-88.
3. Annual Book of ASTM Standards, Vol. 7.02, West Conshohocken, Pa., U.S.A., 2005, p992.
4. AATCC Technical Manual, Vol. 81, 2006, pp99-100.
5. AATCC Technical Manual, Vol. 81, 2006, pp211-212.
6. AATCC Technical Manual, Vol. 81, 2006, pp348-352.

Note: Story by Diana Wyman, AATCC.

防水、疏水、耐水、拒水、抗水、拨水、泼水……相信大家对这些词汇都不陌生,但是如果真要说出这些名词之间的区别,只怕也不是件容易的事情。应该说,主要的原因是对这些词的用法/译法并没有明确的规范和定义,当然,我在这里也不可能给出一个规范,只是根据我的理解说说我对这些概念的看法。

其实这些词汇,其来源都是3个英文词汇——Waterproof、Water Repellent和Water Resistant的不同译法。但是从一开始在不同的领域对这三个词就没有标准的译法,也就造成了后来混乱的局面。下面还是从这三个英文单词出发,来依次分析下这些词汇的内在含义。


防水——Waterproof

防水——Waterproof,这可能是最没有争议的词汇了。简单的定义就是:水无法透过。比如雨衣用的乙烯基塑料薄膜,就是典型的“防水”面料。但是请注意一点是,严格来讲,“防水”没有防水程度的概念,在材料没有破损的前提下,要么防水,要么不防水。

相信肯定会有人马上指出,现在任何一件以防水为卖点的功能服装,都会标明“防水多少多少mm”这样的指标。但严格来说,所有“防水 … mm ”这样的面料,都只能算抗水(Water Resisitant,详见下文),而不是防水。


疏水——Water Repellent

Water Repellent常被译为防水、泼水、疏水、拒水、拨水、抗水等。个人意见,疏水和拨水这两个词较为准确的表达了这个词的真实意义。

疏水和下面要说到的抗水事实上常常混淆,尤其是在中文译名的使用上。为避免歧义,这里再次说明,本文中所用的“疏水”是指在AATCC(American Association of Textile Chemists and Colorists,美国纺织化学师与印染师协会)技术规范(AATCC Technical Manual)里定义的Water Repellent,而“抗水”亦是指同一规范中定义的Water Resistant。

按照AATCC的定义,“疏水性”是指面料防止被水浸湿的能力,而“抗水性”是指面料防止被水浸湿及防止水透过的能力。对于疏水性通常使用两种测试方法,AATCC TM 22(TM:Test Method,测试方法,下同)里定义的“喷雾测试(Spray Test)”和TM 70里定义的“滚筒动态吸收测试(Tumble Jar Dynamic Absorption Test)”。对于测试的内容,我们可以根据名字大概猜得出来是什么意思,具体的细节也没有必要去了解了。总之,我们知道通过测试,我们可以评估出面料相对的疏水性,通常用一个0~100的值来表示。一般来说,疏水性到80~90的面料,就可以挂上“Water Repellent ”的标签了。

关键的一点是,疏水性度量的是面料吸收的水的多少,而不是面料透过的水的多少。


抗水——Water Resistant

上面提到,“抗水性”是指面料防止被水浸湿及防止水透过的能力。AATCC定义了3种测量拒水性的方法:TM 35 “雨测试(Rain Test)”,TM 42 “冲击渗透测试(Impact Penetration Test)”和TM 127 “流体静压力测试(Hydrostatic Pressure Test)”。

雨测试顾名思义就不用多说了,而冲击渗透测试用一定分量的水在一定高度落下冲击面料表面,最终是以透过织物的水的重量来衡量。至于流体静压力测试,则反倒是我们最熟悉的测试方式了,也就是在面料一侧加压,以在面料另一侧出现水珠时的压力作为面料的抗水性指标,也就是我们通常说的,防水能力为…毫米水压。这个测试的重要意义在于明确区分了面料的“抗水性”和面料/纤维的疏水性。面料的抗水性和纤维或纱线的疏水性、粗细、形状、织法、面料的空间结构、微孔大小等多方面因素共同相关。

但是在现在的用法中,通常把使用TM127测试的抗水性大于1500mm的面料称之为“防水面料(waterproof fabric)”。

Tags: 防水面料

关于对拨水性的一点补充
GORE公司在产品培训内容中,有关拨水功能是有专门的说明的,大致的意思是拨水功能(DWR)即对面料表面实施化学处理,起到减小水珠拉力的作用,它不是永久性的,一般在雨中1-2个小时就有可能消失.
而拨水功能对与服装的影响有4点:1、影响服装美观2、加速热量流失(水寒效应),没有拨水性的服装在面料面料潮湿后会发生冷凝,这很容易被误认是面料不防水。3、增加重量4、影响透气性,在水气交换的过程中,有很大原因与服装内外的气压有关系的。

0

阅读 收藏 喜欢 打印举报/Report
  

新浪BLOG意见反馈留言板 欢迎批评指正

新浪简介 | About Sina | 广告服务 | 联系我们 | 招聘信息 | 网站律师 | SINA English | 产品答疑

新浪公司 版权所有