Three requirements for stenter finishing
Formulation formula is a combination of several chemical additives mixed at a certain concentration to achieve a fixed effect. The following results are expected to be achieved through the selection of formulation.
1) Feeling up to customer requirements;
2) Improve some internal indicators to meet customer requirements (such as tear, slip, PH value, etc.);
3) Give consideration to the difficulty of post-process processing (post-process mainly refers to pre-shrinkage and garment making)
Master the Main Characteristics of Auxiliaries
The chemical additives used in stereotyping can be divided into the following categories according to their functions: softeners, antiskid agents, stiffeners, penetrating agents, and PH value regulators. According to ionic type, it can be divided into three types: anion, cation and non-ion. Because the chemical composition of each chemical additive is different, and there are incompatibility taboos among different ionic types, the properties and functions of additives should be fully considered in the selection and formulation of formulation.
Understanding the properties and characteristics of common additives and understanding the intrinsic strength of fabrics (mainly tearing and slipping at present) is helpful to the formulation of setting formula.
Considerations in tentering process
The formulation of formulas focuses on slip and tear strength in terms of physical indicators.
Taking shuttle fabrics as an example, the slippage and tensile strength of plain weave fabrics are poor at low density, and the hand feel is soft at high density; the tear strength is poor at high density, the tear strength is good, the hand feel is hard, and fish scale wrinkles are easy to occur; the longer the float length of twill fabrics is, the worse the slippage is, the higher the tear strength is; the reference plain and twill of DOBBY fabrics; 80S single yarn varieties are non-additives. Often sensitive, and has a certain relationship with the weft tension in the process of processing, so it is necessary to look at the cloth before setting and proofing and formulation after setting; for square weave, weft separation and weighting, weft separation and weighting, warp slip of weft balance, warp balance, weft slip of warp balance; elastic cloth is affected by elasticity, and slip is generally higher than pure cotton products of the same tissue specifications. Plant taller.
Stenter also needs to consider the control of hand consistency between different patterns on the same order. It mainly includes:
1) To adjust the difference of hand feeling caused by different shades and shades of gross effect;
2) Adjust the handle difference between the white cloth and YARN-DYE cloth;
3) To adjust the differences between batches or patterns caused by different processes or processing conditions due to color and other problems;
4) Adjust the differences between batches and patterns caused by internal and external rework. The influence of the process before and after shaping (such as whether to wash, whether to roll, pre-shrinkage speed, etc.) on the hand feeling should also be fully considered in the formulation of the shaping formula.
After having a thorough understanding of the above aspects, we can start to formulate the formula (take shuttle fabrics as an example):
Formulation of normal fabric
1. Analyse the customer's samples (or requirements), understand the style of the samples, and make a preliminary judgment on which additives should be used.
2. According to fabric texture specifications and customer quality standards, the internal strength balance point is analyzed and the dosage of qualified auxiliaries is preliminarily judged.
3. According to the requirements of the order, the combination of colour number dyes and the special needs of the cloth or customers, it is necessary to determine whether the fabric needs to be polished, washed and washed back, which has a great influence on the feel.
4. Do not add too much antiskid agent to improve slip on the basis of too many softeners.
5. Analyse the possible pre-shrinkage speed according to the organization specifications.
6. Select suitable finishing AIDS and dosage according to the above 6 points, and finally determine the soft formula.
Formulation of reworked cloth
The formulation of reworked cloth mainly considers the consistency of hand feel. Especially prominent is the influence of various rework processes on the feel of the fabric. Generally speaking, the soft formula can be formulated as clear water according to the requirement of customers for pH value (pH value adjusted to 5.5-6.5 level) only after stereotyping and rework of the later process. After various kinds of rework, although the additives on the surface of the fabric will be washed off, at the same time some of them will be washed into the fiber interior, which is more conducive to the later process. Improvement of handle.
Therefore, the formulation after washing and rework should be formulated with reference to the pre-washing formulation. Generally speaking, the dosage is about 1/2 of the original formulation (softeners are very few and many must be treated separately depending on the situation); after mercerizing, the softener added to the cloth surface has been destroyed because of mercerizing, and after mercerizing, the shape of the fabric has been finalized. Generally according to the original formula treatment (softener is very small must be treated separately according to the situation).
In a word, the formulation of setting formula is a complex process, which requires a comprehensive understanding of the finishing process and additives, and a thorough analysis of fabric structure and customer requirements before formulating the prescription that meets the requirements.
This requires us to familiarize ourselves with the following elements at first:
1) Customer requirements;
2) Improving touch sensitivity;
3) Analytical ability of sensory style;
4) Analytical ability of fabric structure;
5) Mastering the properties, functions and compatibility taboos of additives;
6) The influence of different finishing processes on the handle of fabrics;
7) Familiar with the influence of different combinations of additives on physical indicators;
8) Minimize the use of softeners, reduce costs while taking into account quality.
After mastering the above aspects, the formulation of stereotyping formula can be targeted.
