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Qualitative Analysis Methods And Suggestions For Regenerated Cellulose Fiber

2010/11/8 14:57:00 334

Fibre Regenerated Cellulose Fiber Standard

Regenerated cellulose fiber

There are many kinds, because the shape of spinneret is different.

fibre

The appearance is different. Even the same spinning fluid can spin fibers with different cross section and longitudinal shape.

The current standard FZ/T01057.3-2007 "textile fiber identification test method third part: microscopy" principle is to observe the longitudinal and cross section shapes of unknown fibers by microscope, and compare the fibers.
标准照片和形态描述来鉴别未知纤维的类别，笔者认为与实际情况不完全相符，故在本文中予以分析且提出几点建议，使再生纤维素纤维的定性更加合理、切实可行。

1 introduction of regenerated cellulose fiber

　　再生纤维素纤维归属化学纤维中的人造纤维，例如：粘胶纤维、铜氨纤维、高湿模量类纤维(如莫代尔纤维)、脱乙酰化醋酯纤维、二醋酯纤维、三醋酯纤维、莱赛尔纤维、竹纤维等，都是利用自然界中存在的含有纤维素的物质如棉短绒、木材、甘蔗渣、芦苇等的纤维素做成的纤维，其中粘胶纤维是由粘胶法得到的再生纤维素形成的;铜氨纤维是由铜氨法得到的再生纤维素形成的;高湿模量类纤维是通过能形成高强力、高湿模量的方法得到的再生纤维素形成的;脱乙酰化醋酯纤维是通过纤维素醋酸酯接近完全的脱乙酰化所得到的再生纤维素形成的;二醋酯纤维的纤维素大分子中至少74%~92%的羟基被乙酰化;三醋酯纤维的纤维素大分子中至少92%的羟基被乙酰化，等等[1][2]。

Since the regenerated cellulose fiber is made by solution spinning, when spinning, the solution is made by wet or dry method, and the shape of spinneret is not unique. It has round, triangular, Y shaped, star shaped, heart-shaped and so on [3]. Even if the shape of spinneret is the same, the fiber cross-section and longitudinal shape will change as a result of spinning conditions. Therefore, the same spinning solution can spin out fibers with different cross-sectional shape and longitudinal shape. Therefore, it is not possible to qualitatively regenerate cellulose fibers based on the shape and longitudinal shape of fibers.

2 Identification and analysis of regenerated cellulose fiber

FZ/T 01057.3-2007 "textile fiber identification test method third part: microscopic method" (principle) is to observe the longitudinal and cross section shapes of unknown fibers by microscope, and to identify the category [4] of unknown fibers according to the standard photographs and morphological descriptions of fibers. The standard lists the cross sectional and longitudinal morphological characteristics of various fibers accordingly in Appendix B, and lists cross-sectional and longitudinal micrographs of various fibers in Appendix C.

The author thinks that in Appendix B and appendix C, except for natural fibers, the description of the cross-sectional and longitudinal features of all kinds of chemical fibers and their micrographs are only one of the various possible appearance forms, which can not be regarded as standard photographs or standard form descriptions.

In fact, for a specific sample, observing the longitudinal or cross-sectional morphology of unknown fibers under microscope, several kinds of unknown fibers (chemical fibers) with different longitudinal or cross section shapes are further identified by chemical reagents. The conclusion concluded may be only a kind of fiber, such as polyester, which is observed directly under microscope.

For synthetic fibers, the final conclusion is what kind of fiber it is.

But for regenerated cellulose fiber, it is necessary to do this with a special method (such as infrared spectroscopy). It is difficult to determine which kind of regenerated cellulose fiber is difficult to use by chemical reagents. Because there are many kinds of regenerated cellulose fibers, and the macromolecular composition is C6H10O5 n, the constituent elements are all carbon, hydrogen and oxygen, but there are some changes in the molecular structure, so there is a vast majority of common properties in the chemical properties, and it is difficult to distinguish between each other with chemical reagents.

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It is considered that: after using chemical reagent to separate the regenerated cellulose fiber (mainly refers to the new type regenerated cellulose fiber such as modal fiber, Lesel fiber and bamboo fiber), after the ordinary viscose fiber, copper ammonia fiber, acetate fiber and three acetate fiber, then the appearance shape (vertical shape and cross section shape) of the regenerated cellulose fiber will be compared with the cross sectional and longitudinal surface characteristics of all kinds of fibers listed in Appendix B of the FZ/T01057.3-2007 "textile fiber identification test method third part: microscope method" and the micrographs of the cross sections and vertical planes of various fibers listed in Appendix C. The names of those who are the same or basically similar can be identified, and the names of specific regenerated cellulose fibers such as modal or Lesel are identified. This is obviously unscientific. Someone

In order to prove its unscientific nature, the author found four modal fibers from a famous large textile mill, one is modal fiber produced in Taiwan, one is modal fiber produced in Austria, one is called new form fiber, the other is modal fiber. These four kinds of modal fibers belong to regenerated cellulose fiber and are all called "modal fiber or new type fiber". The longitudinal shapes of these four kinds of regenerated cellulose fibers are shown in Figures 1, 2, 3, and 4 respectively.

Fig. 1 Austria modal fiber 1

Fig. 2 modal fiber produced in Taiwan

Fig. 3 Shandong new generation fiber

Fig. 4 Austria modal fiber 2

The shape is the same as the groove, but the groove shape, size and number of grooves are different. Even the same modal fiber is also due to the change of the environmental conditions (such as the velocity of the air flow). The appearance of the fiber is different because of the spinning of the spinneret. And each type of fiber is not consistent with or consistent with the cross section and longitudinal shape characteristics of the Dyer fiber, as shown in Appendix B of the third part of the textile fiber identification test method: part FZ/T01057.3-2007: the microscope method (C). From the diagram, we can find that although they belong to modal cellulose fibers, their longitudinal shapes are different from each other.

3 conclusions and recommendations

　　1)有关部门适时对FZ/T01057.3-2007《纺织纤维鉴别试验方法第3部分：显微镜法》进行修订，以免给相关各方造成不必要的困惑和纠纷，如：客户基于自已产品进入市场后顺利销售的需要，要求在检测报告中定性具体再生纤维素纤维名称，如果检测部门不在报告中定性某种再生纤维素纤维，客户就会说“在某某检测部门能定出具体再生纤维素纤维名称，你们这里为什么不行?”，又如：有的检测部门给出了具体再生纤维素纤维名称，且相应产品上据此标注为具体的再生纤维素纤维，其他检测部门在监督检查时，发现其外观形态与FZ/T01057.3-2007《纺织纤维鉴别试验方法第3部分：显微镜法》的附录B中所列各种纤维的横截面、纵面形态特征及附录C中所列各种纤维的横截面、纵面形态显微照片均不相符，此时该如何判定其纤维成份含量合格与否呢?所以，有关部门有必要对FZ/T0

1057.3-2007 "textile fiber identification test method third part: microscope method" is revised.

At the time of revision, it is suggested that the natural fiber part should be retained, and only the chemical fiber part should be specified. The specific description is "a special case of the description of all kinds of chemical fiber appearance and microscopic pictures, and no specific chemical fiber has other kinds of appearance."

2) before the FZ/T 01057.3-2007 "textile fiber identification test method third part: microscope method" has not been revised, the relevant departments have made a unified provision in a suitable way: in the inspection report, the inspection departments or organizations in the inspection report can give the regenerated cellulose fiber, except the new regenerated cellulose fiber, the ordinary viscose fiber, the copper ammonia fiber, the acetate fiber and the three acetate fiber, which can be identified in scientific way or with relevant documentary proof, and can give the name of the specific regenerated cellulose fiber, and all other new regenerated cellulose fibers are uniformly characterized as "other regenerated cellulose fibers".

(Note: "other regenerated cellulose fiber" is different from "ordinary viscose fiber, copper ammonia fiber, acetate fiber, three acetate fiber", because according to the "textile fiber identification test method fourth part: dissolution method" (FZ/T01057.4-2007), the copper ammonia fiber, acetate fiber and three acetate fiber zone can be separated by chemical reagents.

3) when manufacturing enterprises or commercial enterprises mark the content of fiber in related products, they can only mark the name of specific regenerated cellulose fibers only if they can confirm and provide relevant documents to the parties concerned, otherwise, label other regenerated cellulose fibers as appropriate.

4) if the testing organization is qualified for testing the content of the fiber content, if the regenerated cellulose fiber is labeled as a specific regenerated cellulose fiber, such as "cotton 30.5%, modal 69.5%", as long as the test results of the fiber content in the sample are cotton and regenerated cellulose fiber, and the content error is within the permitted range, it can be directly qualified according to the "textile fiber content identification" (FZ/T01053-2007), otherwise it is not qualified, for example, the test result is "cotton 28%, other recycled fiber 72%". At this time, according to the "textile fiber content identification" (FZ/T01053-2007), the fiber content is determined to be qualified.

5) as soon as possible, the relevant departments set up a map library of different regenerated cellulose fibers, because each regenerated cellulose is made up of a specific polymer. No matter how the appearance changes, its molecular structure is definite and its atlas is unique.

At the same time, the corresponding effective and widely accepted testing methods should be worked out so as to make the qualitative and accurate consistency of the fibers in the relevant inspection departments or institutions in the country.