<div><section class="_135editor" data-role="paragraph" id="autoparagraph" style="max-inline-size: 100%; margin: 0px; padding: 0px; border: 0px none; z-index: 0; overflow-wrap: break-word !important; outline: none 0px !important;"><section class="_135editor" data-role="paragraph" style="max-inline-size: 100%; margin: 0px; padding: 0px; border: 0px none; z-index: 0; overflow-wrap: break-word !important; outline: none 0px !important;"><p style="max-inline-size: 100%; margin-bottom: 0px; clear: both; min-height: 1em; cursor: text; line-height: 1.75em; overflow-wrap: break-word !important; outline: none 0px !important;"><span style="max-inline-size: 100%; margin: 0px; padding: 0px; cursor: text; overflow-wrap: break-word !important; outline: none 0px !important;">　　答 从荧光增白剂的增白原理可知，增白剂对纤维或织物的增白效果主要取决于日光中紫外线的含量以及纤维或织物上荧光增白剂的浓度。当日光中紫外线的含量充足时，纤维或织物上荧光增白剂的浓度在一定范围内变化时，其增白效果随纤维或织物上增白剂浓度的提高而增强，也就是被增白纤维或织物的白度值随纤维或织物上增自剂的浓度提高而增大；当增白剂的浓度提高到某一恰当浓度时，增白效果最佳，可获得最高的白度值。如若纤维或织物上的增白剂浓度超过一定范围时（即超过增白剂的泛黄点），非但对纤维或织物的增白效果没有提高，反而会有所降低（即通常所说的纤维或织物泛黄）。</span></p><p style="max-inline-size: 100%; margin-bottom: 0px; clear: both; min-height: 1em; cursor: text; overflow-wrap: break-word !important; outline: none 0px !important;"><br style="max-inline-size: 100%; margin: 0px; padding: 0px; overflow-wrap: break-word !important; outline: none 0px !important;"></p><p style="max-inline-size: 100%; margin-bottom: 0px; clear: both; min-height: 1em; cursor: text; line-height: 1.75em; overflow-wrap: break-word !important; outline: none 0px !important;"><span style="max-inline-size: 100%; margin: 0px; padding: 0px; cursor: text; overflow-wrap: break-word !important; outline: none 0px !important;">　　荧光增白剂DT的最佳使用浓度为0.8％，也就是说用量超过0.8％时，纤维或织物上的白度不但没有提高，相反会下降而导致泛黄。这种现象是因为织物上黄光的强度是有限的，因此抵消该黄光所需要的由荧光增白剂吸收紫外线而发射出的黄光的补色光-蓝紫色光也是有限的。随着织物上荧光增白剂浓度的增加，其发射出的蓝紫色光强度也增加，从而抵消了织物上的部分黄光，使黄光强度逐渐减小，织物也变得越来越白。</span></p><p style="max-inline-size: 100%; margin-bottom: 0px; clear: both; min-height: 1em; cursor: text; overflow-wrap: break-word !important; outline: none 0px !important;"><br style="max-inline-size: 100%; margin: 0px; padding: 0px; overflow-wrap: break-word !important; outline: none 0px !important;"></p><p style="max-inline-size: 100%; margin-bottom: 0px; clear: both; min-height: 1em; cursor: text; line-height: 1.75em; overflow-wrap: break-word !important; outline: none 0px !important;"><span style="max-inline-size: 100%; margin: 0px; padding: 0px; cursor: text; overflow-wrap: break-word !important; outline: none 0px !important;">　　当增白剂的浓度在织物上增加到恰当浓度（即增白剂的泛黄点）时，其发射出的蓝紫光强度恰好与织物上的黄光强度相等，彼此恰好抵消，这时增白效果最好，白度最白。当蓝紫色光强度大于抵消织物上黄光的强度时，增白剂所反射出的蓝紫色光表现极为明显，同时因各种增白剂其组成基团不同，所呈现的不同色调（如青光紫、红光蓝等）这时也较明显地表现出来，上述两种因素综合作用的结果，使织物的灰色色调增加，并且这种作用随增白剂的浓度增加而加强，从而造成白度值下降，增白效果下降。虽然这时织物已无黄光的痕迹，但是看起来已不再洁白、明亮、耀目。</span></p><p style="max-inline-size: 100%; margin-bottom: 0px; clear: both; min-height: 1em; cursor: text; overflow-wrap: break-word !important; outline: none 0px !important;"><br style="max-inline-size: 100%; margin: 0px; padding: 0px; overflow-wrap: break-word !important; outline: none 0px !important;"></p><p style="max-inline-size: 100%; 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