Athletes perform a lot of sweat with intense competitive sports, and the stickiness and wetness caused by sweat often affect the state of the athletes. How to keep the body dry and comfortable during exercise is an important research topic. For the general public, the wet and sticky feeling caused by the hot summer heat also makes many people irritable. Consumers are eager to have a comfortable clothing to improve the hot and humid state in summer or sweaty. Based on the market demand brought by the human body's requirements for comfort, and using the characteristics of the raw materials, a PP unidirectional wet series fabric was developed.
1 design ideas
In order to meet consumer demand for comfort in summer wear, many fabrics have the functions of moisture wicking, moisture absorbing and quick drying, and natural moisture absorption, with the purpose of keeping human skin dry.
Polypropylene yarn and polyester are used to interweave, so that moisture or sweat enters the polyester side from the polypropylene side, but does not enter the polypropylene side from the polyester side, which can achieve the effect of unidirectional wetness. The design has the following advantages.
(1) The use of polypropylene's water-repellent effect can quickly transfer sweat to the outside, keeping the body surface dry and comfortable.
(2) Combining the quick-drying characteristics of polyester, the sweat transmitted from the skin will evaporate as soon as possible, and the appearance of the garment will be maintained.
(3) Avoid direct exposure to polypropylene, delay its aging time, and increase product life.
2 selection of raw materials
Polypropylene, also known as "breathable fiber", has the advantages of small density, light weight, hydrophobicity, quick drying, antifouling, deodorization, abrasion resistance, environmental protection, and good chemical stability.
3 weaving process
3.1 Organization selection
In order to make better use of the characteristics of the two materials, a double-sided structure should be selected, with polypropylene on one side and polyester on the other. The double-sided bird-eye structure is used in this paper.
3.2 Machine Process
The needle cylinder diameter of SD is 30 ", and the rib needle configuration is used. The dial needles are arranged in ABAB order, and the needles are arranged in AABC order.
3.3 Weaving precautions
First of all, because polypropylene does not absorb water and has a large static electricity, it is best to choose a season with higher humidity for weaving, or to re-weave polypropylene yarn in a constant temperature and humidity chamber to improve its weavability.
Secondly, for the weaving of chemical filaments, better needles should be selected to avoid defects such as horizontal stripes and needle marks.
Third, pay attention to the cleanliness of the machine, reduce oil needles, and adjust each feed yarn to make the tension uniform.
4 dyeing and finishing
The fabric dyeing and finishing process is as follows: pretreatment → dyeing → dehydration → setting.
4.1 Dyeing and Finishing
The pre-treatment mainly removes oil stains and dirt on the grey cloth, so as to avoid problems such as blooming during dyeing. In order to ensure better unidirectional wettability of the fabric, non-dyeable polypropylene is used, so single-dyeing polyester is sufficient when dyeing. The process is similar to ordinary polyester dyeing. The process is shown in Figure 2.
Compared with traditional polyester dyeing, the main considerations of this fabric are the following.
(1) The dyeing temperature is appropriately reduced to reduce the damage caused by high temperature to polypropylene. At this time, in order to ensure better color fastness of the fabric, a disperse dye with better dispersion and smaller particles should be selected, and the washing should be strengthened to reduce floating color.
(2) In order to reduce the static electricity when the fabric is worn, a cationic antistatic agent can be appropriately added in the dyeing tank.
4.2 Shape
Because the melting point of polypropylene is only 165 ℃ and it is not resistant to high temperatures, in order to meet the normal feel of ready-to-wear fabrics, the setting conditions are 135 ℃ and 20 m / min (22 yards / min).
5 Product performance
5.1 Test methods and characterization indicators
At present, the one-way wetness test is mainly the one-way transmission index (MMT), which characterizes the one-way transmission capacity of the fabric to the human body. The best, beyond 3 levels is considered to have a unidirectional wet effect.
The test method is to suspend and fix the fabric on the support.A sensor is fixed on the front and back of the fabric. Sweat is simulated with saline, and it is dripped on the front and back of the fabric. Sensors are used to collect data on the diffusion and absorption of salt water. The calculation formula of the final result is one-way passed to the index.
5.2 Test results
The PET / PP fabrics produced according to the methods mentioned in this article have a unidirectional wetness index of 5 and have a very good unidirectional wetness effect.
5.3 Fabric disadvantages
Due to the inherent characteristics of polypropylene, this series of fabrics cannot be used for shrink test, and it is not suitable for traditional paper printing products.
6 conclusion
Polyester / polypropylene unidirectional wet fabric satisfies consumers' requirements for clothing comfort under a state of heavy sweating, can keep the skin surface dry, thereby reducing bacterial growth, preventing odors, etc., and has a very broad market prospect.