Low-formaldehyde stiffening agent TF-630 is a hydroxymethylated amino resin. It is mainly used for stiffening polyester Oxford cloth and other fabrics. It can give the finished fabrics stiffness, long-lasting shape retention, elasticity and other properties. Depending on the lightness and thinness of the fabric, polyester Oxford cloth is generally processed into tents, bags, artificial flowers, advertising cloth, etc. TF-630 can be used alone or in combination with coating finishing agents, flame retardants, etc. to achieve a multi-functional application effect. Since the 1990s, many countries have formulated strict formaldehyde emission standards for textiles from the perspective of environmental protection. my country’s mandatory national standard GB 18401-2003 “National Basic Safety Technical Specifications for Textile Products” issued in 2003 stipulates: Non- The formaldehyde release amount of products that directly contact the skin should be less than 300×10-6. [1] How to achieve the ideal stiffening effect, effectively reduce the free formaldehyde content of the finished fabric, and at the same time reduce the odor of the finished fabric has become important. research topic.
1Experiment
1.1Materials and instruments
Fabric: Polyester Oxford cloth semi-finished product.
Drugs: waterproof finishing agent TG-528A, catalyst TF-630C, flame-retardant coating glue TF-680, non-ionic penetrant TF-107A, low-formaldehyde stiffening finishing agent TF-630 (Zhejiang Chuanhua Co., Ltd.), starch (commercially available , self-cooked into paste).
Instruments: PTM-1A rolling mill, PT-2A hot air tenter (Japan), MP1100B electronic balance (Shanghai Jingke Balance), SF-300 colorimeter (American datacolor), LCK-01 fabric stiffener Moisture tester (Shandong Textile Machinery), Y(B)813 fabric moisture tester (Wenzhou Darong).
1.2 Finishing process
Fabric preparation→Padding (low formaldehyde stiffening agent TF-630)→Baking→Moisture regain→Testing.
1.3 Test standards[2]
The stiffness refers to GB/T 18318-2001 “Determination of Bending Length of Textile Fabrics” and is expressed in terms of bending length. The greater the bending length value, the harder the cloth surface is, and vice versa; the formaldehyde content refers to GB /T2912.1-1998 implementation; Cloth surface odor: The evaluation is based on the results of multiple professionals smelling the cloth surface.
2Results and Discussion
2.1 Factors affecting the finishing effect
2.1.1 Dosage of catalyst TF-630C
Process conditions: padding (drainage rate is about 95%) → baking (180℃, 60s) → moisture regain → test.
It can be seen from Table 1 to Table 3 that the dosage of TF-630C should be controlled within a certain range. As the dosage of TF-630 changes, the dosage of TF-630C should also be adjusted accordingly. The reason is that the appropriate dosage of catalyst can make TF-630 Fully react in a short time and effectively control the free formaldehyde content. If the amount of catalyst is too small, the reaction will be insufficient, resulting in an increase in free formaldehyde content. If the amount of catalyst is too large, the reaction will proceed in the opposite direction, causing TF-630 Hydrolysis, free formaldehyde content also increases. As the catalyst of TF-630, TF-630C has fully considered its chemical reaction activity (catalytic power) during preparation. High activity can reduce the baking temperature or shorten the baking time to complete the delivery. Combined effect. Combined with factory application conditions, the general dosage of catalyst TF-630C for light slurry (TF-630 10~30 g/L) is 12.5%~25.0 (for TF-630 quality, the same below); for medium slurry (TF-63030~ 50g/L) is 12.5%~20.0%; heavy pulp (TF-630 greater than 50 g/L) is 10.0%~16.7%.
2.1.2 Baking temperature
Process conditions: padding (TF-630 50 g/L, TF-630C 10%, liquid squeeze rate about 95%) → baking (60 s) → moisture regain → test.
It can be seen from Figure 1, Figure 2 and Table 4 that as the baking temperature increases, the stiffness of the cloth surface increases significantly, and the formaldehyde content decreases accordingly. When the baking temperature rises to 210°C, the cloth surface after baking There is a slight peculiar smell in the noodles. Based on the factory application conditions, it is recommended that the factory set the baking temperature to 190~200℃.
2.1.3 Baking time
Process conditions: padding (TF-630 50 g/L, TF-630C 20%, liquid squeeze rate about 95%) → baking (180℃) → moisture regain → test.
It can be seen from Figure 3, Figure 4 and Table 5 that as the baking time is extended, the stiffness of the cloth surface increases significantly and the formaldehyde content also decreases. However, when the baking time is extended to 120 s, the cloth surface has a slight The peculiar smell appears. Combined with the cloth surface effects produced by different baking temperatures, the reason is analyzed and concluded: the baking temperature is too high and the time is too long, which easily produces trimethylamine [(CH3)3N] during the reaction of TF-630, causing The finished fabric has a fishy smell. [3] Therefore, when finishing, you can increase the baking temperature and reduce the baking time accordingly, or lower the baking temperature and increase the baking time accordingly, both of which can achieve ideal results. The application effect. Based on the actual situation of the factory, for fabrics with a mass per unit area of 200 g/m2, it is recommended to use a vehicle speed of 60~70 m/min.
2.1.4 No catalyst
Process conditions: padding (drainage rate is about 95%) → baking (180℃, 60s) → moisture regain → test.
It can be seen from Figure 5, Figure 6 and Table 6 that under conventional process conditions, when TF-630 is used alone for finishing, the more TF-630 is used, the higher the free formaldehyde content on the cloth surface and the heavier the odor on the cloth surface. The increase in stiffness is not obvious. The reason is that although TF-630 can be completely cured without a curing agent under the action of high temperature, infrared rays, etc., it requires a longer reaction time. Under the conventional process conditions of the factory, TF-630 reacts It is very incomplete. Therefore, it is recommended that factories use TF-630 for finishing and use appropriate catalysts at the same time, so that TF-630 can be completely cured in a short period of time.
2.2 Compound finishing with other additives
2.2.1 Non-ionic penetrant TF-107A
Process conditions: prevent water (waterproof degree reaches 60~70 points, liquid removal rate 33%) → padding (TF-630 30 g/L, TF-630C 20%) → baking (180℃, 60 s) → moisture return →Test.
It can be seen from Figure 7 and Figure 8 that under the premise that the permeability of the fabric is relatively poor, adding non-ionic penetrant TF-107A can accelerate the penetration of the working fluid into the fabric, significantly increase the liquid-carrying rate of the fabric surface, and increase the stiffness of the fabric surface. TF The dosage of -107A can be controlled at 1~3 g/L.
2.2.2 Starch paste
Process conditions: padding (TF-630 30 g/L, TF-630C 20.0%) → baking (180℃, 60 s) → moisture regain → test.
It can be seen from Figure 9 that adding starch paste can significantly improve the stiffness of the cloth surface. When 30 g/L of starch paste is added, the resulting paste becomes jelly-like after being left for 12 hours after cooling, which affects the use effect. When 20 g/L is added , it can be left for about 168 hours (7 working days) after cooling. It is recommended to add 10~20 g/L of starch paste. If you are processing white fabrics, you need to be careful considering that starch paste can easily produce mold spots in a humid environment. Use.
2.2.3 Coating glue
Process conditions: sizing → scraping → baking (170℃, 60 s) → evaluation.
It can be seen from Table 7 that adding a small amount of TF-630 to the coating glue can significantly improve the rubbing fastness of the coated fabric.
2.2.4 Cleaning up with the same bath
Process conditions: padding→baking (180℃, 60 s)→moisture regain→test.
The effect of adding TF-630 on the waterproof effect is shown in Table 8. The effect of adding TF-630 on the waterproof effect and fabric stiffness is shown in Table 9.
It can be seen from Table 8 and Table 9 that adding a small amount of TF-630 can be used as a cross-linking agent to improve the washing fastness. It is recommended that the dosage of TF-630 is 3~5 g/L and TF-630C 1 g/L. Increasing the dosage of TF-630 can significantly improve the stiffness of the fabric without affecting the waterproof effect. It is recommended that when processing fabrics with waterproof and stiff requirements (such as tents), factories can finish the waterproof and stiff fabrics in the same bath to shorten the process.
2.3 Factory mass production
(1) The sample unit is a printing and dyeing factory in Taizhou, the fabric type is dark polyester Oxford cloth, the setting temperature is 200℃, the setting speed is 80 m/min, TF-630 36g/L, TF-630C 7.2 g/L, the fabric has bending resistance after finishing The length is 37.6 mm, and the free formaldehyde content on the cloth is 59.9×10-6.
(2) The sample unit is a unit in Wujiang, the fabric is red Oxford cloth, the setting temperature is 200℃, the setting speed is 100 m/min, TF-630 100 g/L, TF-630C 10 g/L, the bending length of the finished fabric 78.9 mm, the free formaldehyde content on the cloth surface is 286×10-6.
3Conclusion
(1) Stiff finishing agent TF-630 is suitable for polyester Oxford cloth. During the finishing process, when ρ (TF-630) = 10~30 g/L, w (TF-630C) = 12.5% ~ 25.0%; when ρ When (TF-630)=30~50 g/L, w(TF-630C)=12.5%~20.0%; when ρ(TF-630) is greater than 50 g/L, w(TF-630C)=10.0% ~16.7%. Control the baking temperature to 190~200℃. Baking time
It should be adjusted according to the mass per unit area of the fabric. When the mass per unit area of the fabric is less than 100 g/m2, use a vehicle speed of 80~110 m/min; when the mass per unit area of the fabric is 100~200 g/m2, use a speed of 70~90 m /min vehicle speed; when the fabric unit area mass is greater than 200 g/m2, the vehicle speed is 60~70 m/min.
(2) When the stiffening finishing agent TF-630 is used to process fabrics with poor initial penetration effect, 1~3 g/L non-ionic penetrating agent TF-107A can be added, which can significantly improve the liquid removal rate of the fabric and improve the stiffness of the fabric after finishing. degree; adding 10~20 g/L starch paste can significantly improve the stiffness of the finished fabric; TF-630 can be finished with the same bath, and a small amount of TF-630 can be added as a cross-linking agent to improve the washing fastness [ ρ(TF-630)=3~5 g/L, ρ(TF-630C)=1 g/L]. Increasing the dosage of TF-630 can significantly improve the stiffness of the fabric without affecting the waterproof effect; flame retardant coating When TF-630 20 g/L is added to the layer glue, the rubbing fastness of the coated fabric can be significantly improved.
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