Coating stripping method for coated fabric
Coating stripping method for coated fabrics
Abstract: Before quantitative analysis, the coated fabric must be stripped. Taking commonly used polyacrylate (PA), polyurethane (Pu), and polyvinyl chloride (PVC) coated fabrics as research objects, five solvents were selected as coating strippers, peeling tests were conducted under different conditions, and the right There are three types of coating strippers that have peeling effects on different coatings. Among them, tetrahydrofuran has the best effect and can completely peel off the coating in 5 minutes at room temperature. At the same time, 15 types of fibers that may be damaged by solvents were analyzed, and peeling methods were found for 11 of them.
Coated fabric means covering a fabric (or nonwoven fabric) with a layer of polymer or other materials to form a composite of fabric and polymer. 『1 According to the coating material, it can be divided into polyacrylate (PA) coating, polyurethane (PU) coating, and polyvinyl chloride (PVC) coating. The coating can not only improve the physical properties of the fabric, but also cover up defects on the fabric surface. It is widely used and favored by consumers. The commonly used method for quantitative analysis of textile components is the dissolution method. However, many coated fabrics have coatings on their surfaces and cannot be accurately quantitatively analyzed. The coating must be peeled off before quantitative analysis of fibers. Currently, none of the test methods for component analysis mention how to peel off the coating. Relevant studies include: using N, N-dimethylformamide (DMF) to strip the PU coating of viscose fabrics; using DMF as a stripping agent for the PU and PA coatings of polyester-cotton coated fabrics.
[3怀Each stripper has limitations. For example, DMF cannot be used on coated fabrics containing spandex and acrylic. This article analyzes the test conditions and application scope of several strippers. 1 Test 1.1 Materials and reagents Materials: 2 types of PA, PU, and PVC coated fabrics, numbered PAl, PA2, PU1, PU2, PVC1, PVC2 respectively. The PA2 base fabric fiber is nylon, and the other 5 base fabrics are The fiber is polyester. Among the six selected coated fabrics, the coating and the fabric have obvious distinguishing characteristics. The coating and the base fabric have different colors. It is easy to observe the peeling off of the coating during the test. Reagents: tetrahydrofuran, ethyl acetate, acetone, N, N-dimethylformamide (DMF), cyclohexanone (commercially available). 1.2 Peeling temperature
et al. 51 will conduct coating peeling tests on 6 types of coated fabrics using 5 selected solvents. A constant temperature water bath was used to control the temperature, and the test temperature was selected based on the boiling points of the five solvents. The boiling points of tetrahydrofuran, ethyl acetate, acetone, DMF, and cyclohexanone were 65.4°C, 77.1°C, 56.5°C, and 152. 8℃, 155.7oC. Therefore, the test temperatures are: tetrahydrofuran at room temperature, 40℃, 6O℃, ethyl acetate at room temperature, 40℃, 60℃, acetone at room temperature, 40℃, DMF at room temperature, 40℃, 7O℃, 95℃, cyclohexanone at room temperature, 40℃ ℃, 70℃, 95℃. By observing the peeling conditions of the coating at different temperatures, the appropriate peeling conditions can be determined. 2 Results and Discussion 2.1 The peeling effect of different solvents on the coating at different temperatures is known from 1. The five selected solvents have a peeling effect on PA, PU, and PVC coatings within 30 minutes, but the peeling effect and peeling The conditions are very different: Tetrahydrofuran, DMF, and cyclohexanone can completely peel off six coated fabrics; ethyl acetate and acetone have better peeling effects on PVC coatings, but can only partially peel off PA and PU coatings. ． In view of the fact that the type of coating is generally not clear during coating stripping before quantitative testing, this requires the selected coating stripper to have a wide stripping range. Therefore, tetrahydrofuran, DMF, and cyclohexanone can all be considered as general-purpose coatings. Stripping agent. Tetrahydrofuran can completely peel off the coatings of 6 types of coated fabrics at room temperature and 5 minutes. Compared with other solvents, it has great advantages in both test temperature and test cycle; DMF has unsatisfactory peeling effect at low temperature. Under ℃ conditions, 6 types of coated fabrics can be completely peeled off in 10 to 20 minutes. Therefore, the peeling test conditions are set at 95cI, 20 minutes. When cyclohexanone is increased from room temperature to 40℃, the peeling speed and peeling effect are improved. , the peeling effect will no longer change after continuing to heat up to 40°C. The coatings of the six coated fabrics can be completely peeled off in 10 to 30 minutes. Therefore, the test conditions for cyclohexanone are set to 4O°C, 30min. 1The peeling effect of different solvents on coatings at different temperatures Solvent temperature/°C
2.2 Effect of stripper on fibers of coated fabric base fabric Any solvent may cause damage to some fibers when stripping off the coating. According to the solubility properties of common textile fibers in Appendix A of FZ/T01057.4-2007, 2 It is known that the three solvents used may cause damage to 15 types of textile fibers, including common polyester, acrylic and spandex. Some fibers are not suitable for several strippers. For coated fabrics with such fibers, special attention needs to be paid when selecting a coating stripper. In addition, temperature has a great influence on the solubility of fiber. In the same solvent, many fibers do not dissolve at room temperature but may dissolve under boiling conditions. Therefore, the choice of coating stripping method needs to consider the solvent type and dissolution temperature. 2The influence of the selected solvent on some fibers Note: s. Generation s dissolves immediately, generation s dissolves, generation P partially dissolves, generation I does not dissolve, the same below. 2.3 Selection of coating stripping method for special coated fabrics 2.3.1 Fibers that are not suitable for general solvents Partially applicable fibers Coated fabrics containing the 15 types of fibers involved in 2 are regarded as coated fabrics under special circumstances. Based on the solubility properties of the fiber in the selected solvent, 11 of them are suitable for at least 1 of 3 general solvents, and the coating stripping method can be selected.�See 3.3 for the selection of coating stripping methods for several special coated fabrics. It can be seen from 3 that among the three recommended general solvents, only DMF can be used for coated fabrics containing polystyrene fibers; only tetrahydrofuran can be used for coated fabrics containing spandex; For fibers containing polylactic acid, only cyclohexanone can be used; for fibers containing 8 types of fibers such as acrylic and polypropylene, there are 2 coating strippers to choose from.
2.3.2 Among the 15 types of fibers involved in 2, all the fibers that are not suitable for general solvents are chlorine, polypropylene, triacetate, and cellulose acetate. They are not suitable for the three general solvents of tetrahydrofuran, cyclohexanone, and DMF. The solubility properties in acetone and ethyl acetate are as shown in 4.4. The solubility properties of fibers that are not suitable for all general solvents in other solvents can be seen from 4. Polyvinyl chloride, polyvinyl chloride and triacetate are in acetone or ethyl acetate. Insoluble. According to 1 test results, acetone or ethyl acetate can peel off part of the coating at room temperature, so coated fabrics containing chlorine, polypropylene, and triacetate can try acetone or ethyl acetate, which may It is effective on some coated fabrics; acetate fiber will dissolve in acetone or ethyl acetate, so the five solvents in this test are not applicable to coated fabrics containing acetate fiber. 3 Conclusion No. 12 Zhu Hongliang, et al.: Coating peeling method of coated fabric 53 (1) Tetrahydrofuran, ethyl acetate, acetone, DMF, and cyclohexanone all have peeling effects on PA, PU, and PVC coatings, but the peeling effect and stripping conditions are very different. (2) Tetrahydrofuran, DMF, and cyclohexanone can be used as general-purpose coating strippers. Among the three general-purpose coating strippers, tetrahydrofuran has a low test temperature, short test period, and good stripping effect, and is the preferred coating stripper. agent. f3) Three general-purpose coating strippers: Tetrahydrofuran, DMF, and cyclohexanone may cause damage to 15 common textile fibers, but 11 of these 15 fibers have at least 1 method can be applied, and a suitable coating stripping method can still be found. (4) Coated fabrics containing polyvinyl chloride, polyvinylidene, triacetate, and acetate are not suitable for the three general solvents of tetrahydrofuran, cyclohexanone, and DMF, and further research is needed.
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