Manufacturer of Reduced Weight Fabric Tear Testers Shares Impact of Finishing Process on Physical and Mechanical Properties

Note: Tests on softness, shrink prevention, flame retardant finish, and physical and mechanical properties of the wool fabrics involved in this article were all conducted under standard laboratory conditions.

Woolen fabric has a unique appearance style and excellent heat retention function. The common functional finishing of woolen fabric mainly includes soft finishing, anti-felting finishing, flame-retardant finishing, anti-static, anti-ultraviolet, tri-proof finishing, etc. The main objective of soft finishing is to improve the feel and elasticity of fabrics. Therefore, most soft finishing researchers focus on the changes in wrinkle recovery, bending length and friction factor of fabrics, and explore the special soft finishing process. There is very little information on soft finishing. Changes in resistance towear and pilling properties of post-wool fabrics.

1. The finishing process of woolen fabrics

The sample is an all-wool fabric, supplied by a wool spinning factory in Shanghai. The warp density is 195.5 threads/10 cm, the weft density is 185 threads/10 cm, and the areal density is 174.5 g/m.

1. The process of softening and finishing wool fabrics

The fabric softener is CibaUltratexUMnew, with a pH value of 4.5 to 6.5. Process flow: Soak the fabric sample in 40L of softener solution with a liquor ratio of 1:30. Soak it for a few minutes at around 25°C. Dip it twice and dab it. The filling rate is around 50%. Put the fabric sample at 70-80°C. Pre-bake ℃ for 5 minutes – bake at 110℃ for 3-4 minutes then remove the fabric sample.

2. Process offlame retardant finish of wool fabrics

The flame retardant is cibaFlovanBU, pH value 6.5-7.0.

Process flow: Dip the woolen fabric twice in the working solution and stuff it twice (the stuffing rate is kept at 50%) - dry at 0 °C - bake at 120°C. °C for 5 minutes – remove samples.

3. The anti-shrinkage finishing process of wool fabrics

The anti-shrinkage agent is water-soluble polyurethane with a pH value of 6.0 ~ 7 ,0. Process flow: Dip and roll woolen fabric twice in water-soluble polyurethane working solution - dry at 80°C for 5 minutes - bake at 160°C for 3 minutes and remove sample tissue.

2. Testing the physical and mechanical properties of wool fabrics before and after finishing

1. Standards and test equipment

The preparation procession and fabric sample testing is based on the recently released national standards, and the experimental equipment is electronic fabric strength machine, fabric falling weight tear tester, wrinkle elasticity tester, fabric pilling tester and fabric abrasion resistance tester (pressure weight is 250g, A.100 type coarse carbonization wheel).

2. Testing the physical and mechanical properties of wool fabrics

The experimental data listed in this article all meet the requirements of experimental error The average of multiple test data. The table shows that regardless of the type of finish, fabric density and surface density are improved to varying degrees. This is mainly because there is no tension treatment when finishing fabrics in the laboratory. Even in large-scale production, the densitywarp and weft of the fabric will increase (the finished fabric is denser than gray fabric) and the fabric will shrink to a certain extent in the warp and weft direction. Moreover, all the arrangements this time are “additive arrangements”.

3. Analysis of differences in physical and mechanical properties before and after finishing

1. Difference Analysis of Tensile Breaking Properties

The data shows that the warp and weft density of the fabric after soft finishing increased by 3.32% and 4.32 % respectively, as well as the strength of the warp and weft. simultaneously increased by 3.24% and 3.00%. The elongation at break decreased by 0.8% and 4.74%.

Taking into account the influence of the density of the fabric after finishing, it can be considered that: when finishing with a silicone softener, the C-Si bond between the methyl group and silicon is a saturated ∝ bond, rotates freely; whilethe side chains and end groups are both methyl groups and cannot cross-link into a network structure; and the methyl groups are directionally arranged, have low polarity and low interaction force, so that there is no reinforcing effect, and the soft-finish fabrics have warp directions and frame. There is no significant change in the breaking strength, while the elongation at break in the warp and weft directions decreases slightly. After flame-retardant finishing, the warp and weft density of the fabric increased by 8.70% and 14.86% respectively, the warp and weft strength decreased by 11.59% and 4.14%, and the elongation at break of warp and weft increased.relaxed by 9.98% and 7.07%. . After considering the influence of density, it can be considered that after a flame retardant finish, because the fibers do not slide easily and some fibersare damaged, the warp and weft breaking strength of the fabric decreases considerably, while the elongation of the warp at breaking. increases to a certain extent. After anti-felting finishing, the warp and weft density of the fabric increased by 4.35% and 8.92% respectively, the warp and weft strength increased by 3.97% and 2.74%, and the elongation at warp and weft breakage decreased by 0.2% and 1.92%. . %. After taking into account the influence of density, it can be considered that if a water-soluble polyurethane anti-felting finish is used, the warp and weft breaking strength of the fabric will be slightly reduced and the impact will be low, while the warp and weft elongation at break will not change significantly. From the point of view of the tensile breaking work of the fabric, there is no significant change in the fabric after soft finishing and anti-felting finishing, while the work ofChain breakage after a flame-retardant finish decreases significantly.

2. Tear performance difference analysis

The data shows that the tearing of fabrics in the warp and weft directions after soft finishing The strength increased significantly, mainly due to of the effect of the softener, which is 121.2. , the latitudinal direction is 115. , the chain elastic recovery angle after soft finishing is 119.6. , the latitudinal direction is 113.8. ; After fireproof finishing, the southern elastic recovery angle is 108.6. , the latitudinal direction is 92.8. ; And the warp elastic recovery angle after anti-felting finishing is 138.4. , the latitudinal direction is 127.8. .

Generally, the density of the tissue is inversely proportional to its wrinkle recovery. The higher the density, the worse the elasticity. Co considerationcomprehensive changes in density of the fabric shows that the elastic recovery in the warp and weft directions of the fabric after softening treatment has basically not changed; while the elasticity in the warp and weft directions of the fabric deteriorated after flame retardant treatment. This is mainly because the whole fabric becomes stiff after the flame retardant treatment. , so that after wrinkles are caused by external pressure, the elastic recovery performance deteriorates; and the elasticity of warp and weft fabrics after anti-shrinkage finishing is significantly improved, mainly because the formation of water-based polyurethane film has good elasticity, which increases the elasticity of the fabric.

3. Analysis of differences in anti-pilling properties

Wool fabrics will pill after being treated with silicone softener. Performance has slightlydecreased, which is related to the fact that the fibers of the fabric yarn are easier to slide in and out after soft finishing; wEven after flame retardant and anti-felting finishing, the anti-pilling performance of the fabric increased slightly, which was mainly due to the flame retardant. The agent and the anti-shrink agent cross-link with the fibers to form a network structure, thereby improving the anti-pilling performance of the fabric to a certain extent.

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