CN112301725B

CN112301725B - Waterproof fabric obtained by plasma technique

Info

Publication number: CN112301725B
Application number: CN201910713106.9A
Authority: CN
Inventors: 林子聪; 陈永敏
Original assignee: Hong Kong Research Institute of Textiles and Apparel Ltd
Current assignee: Hong Kong Research Institute of Textiles and Apparel Ltd
Priority date: 2019-08-02
Filing date: 2019-08-02
Publication date: 2023-04-07
Anticipated expiration: 2039-08-02
Also published as: WO2021023120A1; CN112301725A

Abstract

本发明涉及通过等离子体技术获得的防水织物及其制备方法。本发明的等离子体技术处理仅施用于表面，可以保持材料的整体性质，由此获得的防水织物经过洗涤后有时仍具有防水性能。The invention relates to a waterproof fabric obtained by plasma technology and a method for its preparation. The plasma technology treatment of the present invention is only applied to the surface, which can maintain the bulk properties of the material, and the waterproof fabric thus obtained is sometimes still waterproof after washing.

Description

Water-repellent fabric obtained by plasma technique

Technical Field

The present invention relates to a waterproof fabric obtained by plasma technology and a process for its preparation.

Background

Natural fibers, such as cotton and wool, provide an environment with heat, moisture and oxygen that promotes the growth of microorganisms and ultimately causes malodor and deterioration of laundry. In addition, these materials are likely to absorb moisture, thereby promoting the growth of microorganisms. To address these problems, chemical finishing processes are used to apply functional coatings to textile materials.

The water repellent treatment is achieved by using fluorocarbon, silicone, paraffin and stearic acid-melamine which reduce the surface tension of water to spread water droplets. The water repellent treatment also increases resistance to acids, bases and other chemicals.

These chemical treatments are applied from solution to the outside of the laundry mainly by two different methods, i.e. the dip method and the tumbler method. The dipping method requires sufficient water, where the material to liquid ratio (MLR) is 1. Both methods require long processing times (-1 h) and two thirds of the processing time require heating (drying and curing) (i.e. with large energy consumption).

The plasma technology is a pollution-free, safe, economical and water-free process, and is a new method for water-proof treatment. It is a well-developed process and can be applied to a variety of materials.

Disclosure of Invention

The invention provides a waterproof fabric obtained by a plasma technology and a preparation method thereof. Plasma technology treatment is only applied to the surface and thus the bulk properties of the material can be maintained.

According to one aspect, the present invention provides a fabric having a coating comprising a coating material selected from the group consisting of: hexamethyldisiloxane, 2,4, 6, 8-heptamethylnonane and methylhydrogensiloxane; and the coating is plasma treated before or after coating.

According to some embodiments, the fabric of the invention is selected from cotton fabric or wool fabric.

According to another aspect, the present invention provides a method of preparing the above coated fabric, comprising the step of applying a coating after treating the fabric with plasma.

According to some embodiments, the plasma used for the plasma treatment according to the invention is selected from nitrogen, argon, oxygen, n-heptane and/or air.

According to some embodiments, the plasma treatment is performed under low pressure conditions. The preferred pressure is 5x10 ⁰ Pa to 8x10 ² Pa. The plasma treatment time may be 1-10min.

According to some embodiments, the plasma treatment is performed one or more times.

According to some embodiments, when the coating material is hexamethyldisiloxane, the method comprises the following two steps:

i) Treating the fabric with Ar plasma; and

ii) treating the fabric with a hexamethyldisiloxane plasma to effect plasma polymerization to form a coating on the fabric surface.

According to some embodiments, the power and processing time of the plasma machine may have some effect on the coating effect. Generally, the power is higher and the treatment time is longer, which is beneficial for coating. For example, for HHMDSO plasma pretreatment, the plasma treatment time of the coating material is generally more than 2min at a power of 100W; the plasma treatment time of the coating material is more than 5min when the power is 50W.

According to some embodiments, the method further comprises introducing a coupling agent to the surface of the fabric.

According to some embodiments, when the coating material is 2,2,4,4,6,8,8-heptamethylnonane, its concentration in n-heptane is 10%. In this method, the fabric can be coated by treating the fabric with 2,4, 6, 8-heptamethylnonane for 1 minute.

According to some embodiments, when the coating material is methylhydrogensiloxane, the coating is performed at room temperature.

According to some embodiments, the concentration of methylhydrogen siloxane is 0.5% to 2%, such as 0.5% to 1.5%, 0.75% to 1.5%, more specifically 1% methylhydrogen siloxane.

According to some embodiments, the method comprises plasma treatment with 1% methylhydrogensiloxane, a plasma power of 400W, and argon for 1 minute.

According to some embodiments, when the coating material is methylhydrosiloxane, the coating step uses a catalyst selected from the group consisting of: zinc octoate, iron octoate, dibutyltin dilaurate, and tin octoate.

Drawings

Figure 1 SEM images of hmdso coated on cotton fabric.

Figure 2. Contact angles measured for three HMDSO plasma treated cotton fabrics.

Figure 3 SEM image of water barrier obtained by coating hmdso on wool fibers.

FIG. 4 is a diagram showing the water-repellent effect of HMDSO after the introduction of a coupling agent.

Fig. 5 SEM image of HMN without HMN coating on cotton fibers.

Figure 6. Contact angles measured for HMN/n-heptane/Ar plasma treated cotton fabrics.

FIG. 7 SEM image of a methylhydrogensiloxane-forming coating. (a) untreated (b) HMDSO plasma 100W treated wool fibers for 2min, (c) HMDSO plasma 100W treated wool fibers for 8min (d) HMDSO plasma 100W treated wool fibers for 20min

Figure 8. Water contact angle measurement images of methylhydrogensiloxane plasma treated cotton and wool samples.

FIG. 9 Water repellent treatment of cotton fabrics with continuous flow [ P =400W ] of 2,4, 6, 8-Heptamethylnonane (HMN) and n-heptane/Ar at different concentrations

FIG. 9 (continuation) Water repellent treatment of cotton fabrics with continuous flow [ P =400W ] of 2,4, 6, 8-Heptamethylnonane (HMN) and n-heptane/Ar at different concentrations

Fig. 10. With a continuous flow of 2,4, 6, 8-Heptamethylnonane (HMN) and n-heptane/Ar [ HMN/n-heptane = 10; p =400W ] carrying out water-proofing treatment on cotton fabric for different time

FIG. 11. Water repellent treatment of Cotton fiber Using different concentrations of MethylHydrosiloxane [ Ar plasma treatment, power =400W, time =1min ], and washing successively five times with Home laundry device and detergent FIG. 12 Water repellent treatment of Cotton fiber [ Ar plasma treatment, power =400W, time =1min ] (laundry method: AATCC test method 61-2010, condition 2A)

Fig. 12 (continuation 1) water-repellent treatment of cotton fiber with methylhydrogensiloxane at different concentrations [ Ar plasma treatment, power =400W, time =1min ] (laundry method: AATCC test method 61-2010, condition 2A) fig. 12 (continuation 2) water-repellent treatment of cotton fiber with methylhydrogensiloxane at different concentrations [ Ar plasma treatment, power =400W, time =1min ] (laundry method: AATCC test method 61-2010, condition 2A)

FIG. 13 Water repellent treatment of Cotton fibers with 2% methylhydrogensiloxane and Heat curing at 160 ℃ for 30min (laundry method: AATCC test method 61-2010, condition 2A)

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail with reference to the following embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

I. Plasma treatment

The plasma treatment of the present invention is carried out in a laboratory scale low pressure plasma treatment system. A Radio Frequency (RF) generator provides a variety of powers to establish a plasma field at a reduced pressure between two parallel electrodes. In this system, three gas inlets allow for the simultaneous application of multiple gases. Some of the liquid monomer is transferred to the reaction chamber through an evaporator. The specifications of the press are as follows:

gas used	Nitrogen, argon, oxygen, n-heptane/air
		Flow rate of flow	Maximum 10l/min
Pressure of	5x 10 ⁰ Pa to 8x10 ² Pa
		Time of treatment	0.5min to 10min
Power of	Maximum 400W
		Temperature of	At room temperature

II. materials

The wool fabric is 100% merino wool, the single-sided knitted fabric has the weight of 265g/m ² The structure is 22 stitches per inch in the wale direction and 16 stitches per inch in the lateral direction.

The cotton fabric is 100% cotton and is divided into two types: i) Single-knit fabric having a weight of 230g/m ² The structure is 48 needles per inch in the longitudinal direction and 30 needles per inch in the transverse direction; and ii) a scoured and bleached plain weave fabric,the fabric weight is 265g/m ² . The water repellent treatment of these two types of cotton fabrics was investigated.

Characterization of

i) Durability of laundry

Laundry durability evaluation was performed according to the following: i) AATCC test method 61-2010, condition 2A; or ii) ISO 6330. In AATCC test method 61, the fabric is cut into 50mm by 150mm pieces and washed in a rotating closed tank containing 150ml of an aqueous solution of AATCC standard WOB detergent (0.15%, w/v) and 50 stainless steel balls, in which a thermostatic water bath is controlled at 49 ℃ and at a speed of 40 + -2 rpm for 45min. A single 45min wash cycle corresponds to 5 domestic wash cycles. In ISO 6330, test procedure 4N, the fabrics are washed in a drum washing machine at 40 ℃ for 15min and rinsed 4 times, then drum dried at a temperature <60 ℃ and repeated 20 times. For test procedure 4H, the fabrics were washed in a 40 ℃ drum washer for 1min and rinsed 2 times, then flat dried and repeated 20 times. Ii) water resistance

Water repellency was assessed by AATCC test method 22-2014. 250ml of distilled water was sprayed onto the sample surface and the wetting of the sample surface was compared to AATCC picture standards. The contact angle of the treated fabric was measured using the drop method. 1 drop of about 4-6. Mu.l of distilled water was placed on the fabric. The contact angle was calculated by measuring the height and length of the drop. Values greater than or equal to 80 should be obtained to meet the requirements.

iii) Surface analysis

The surface morphology of the coating was examined by Scanning Electron Microscopy (SEM).

Water-proofing treatment

i Hexamethyldisiloxane (HMDSO)

The water repellent functional treatment by plasma technique using Hexamethyldisiloxane (HMDSO) was studied (table 1). The process comprises two steps: i) Pre-treatment with Ar plasma to help enhance the adhesion between the substrate and the coating; ii) plasma polymerizing with HMDSO plasma to form a water repellent coating on the surface of the substrate. HMDSO was successfully applied on cotton-like fabrics and water repellency was obtained, which was also confirmed by SEM (fig. 1). The contact angle of the treated fabric was also studied, averaging about 125 ° (fig. 2). A water repellent functional coating was also obtained on wool fibers as confirmed by SEM (figure 3).

TABLE 1 waterproofing of cotton fabrics with HMDSO

Although a water repellent functional coating can be obtained using HMDSO plasma, the water repellent performance cannot be maintained after a single wash (table 2).

TABLE 2 Water repellency treatment Using HMDSO

^a AATCC22 waterproof: spray test

In order to improve durability, a coupling agent (silane coupling agent a-151) was introduced (fig. 4), which allows the water-repellent function to be maintained after a single wash. As can be seen in fig. 4, the water repellent layer is obtained by plasma treatment for 1min at a power of 400W, for example, and the water repellent effect is maintained after a single washing.

ii.2,2,4, 6, 8-Heptamethylnonane (HMN)

Hydrocarbon-based waterproofing agents 2,4, 6, 8-Heptamethylnonane (HMN) under various reaction conditions were also investigated (Table 3), but the waterproofing function was not obtained. SEM images also confirmed unsatisfactory results, in which no HMN coating was formed on the cotton fibers (fig. 5). This is because the evaporated HMN condensed before reaching the fabric sample and therefore did not react. Therefore, the agent is introduced by the dipping method, but the waterproof function is still not achieved. This is probably because the etching process of argon overrides the polymerization process to become a major process and therefore does not produce a water-repellent coating.

TABLE 3 Water repellency treatment conditions and test results for cotton fabrics with 2,2,4,4,6,8,8-Heptamethylnonane (HMN)

Reagent	Power of	Temperature of	Time	Water-proof property
					HMN	15W	70℃	5min	Is free of
HMN	15W	70℃	10min	Is composed of
					HMN	30W	70℃	5min	Is free of
HMN	30W	70℃	10min	Is composed of
					HMN	50W	70℃	5min	Is free of
HMN	50W	70℃	10min	Is free of
					HMN	100W	70℃	5min	Is free of
HMN	100W	70℃	10min	Is free of
					HMN	200W	70℃	5min	Is composed of
HMN	200W	70℃	10min	Is free of
					HMN ^a	300W	RT	3min	Is free of
HMN ^a	300W	RT	4min	Is free of
					HMN ^a	300W	RT	5min	Light and slight
HNM/n-heptane ^b	100W	RT	3min	Is free of
					HNM/n-heptane ^b	100W	RT	5min	Is free of
HNM/n-heptane ^b	100W	RT	7min	Is free of
					HNM/n-heptane ^b	300W	RT	3min	Is free of
HNM/n-heptane ^b	300W	RT	5min	Is free of
					HNM/n-heptane ^b	300W	RT	7min	Is free of
HNM/n-heptane ^b	400W	RT	3min	Is free of
					HNM/n-heptane ^b	400W	RT	5min	Is free of
HNM/n-heptane ^b	400W	RT	7min	Is free of

^a HMN applied by dipping

^b HMN/n-heptane [1]Applied by dipping

TABLE 4 Cotton fiber repellency with continuous flow of 2,4, 6, 8-Heptamethylnonane (HMN) and n-heptane/Ar

Conditions of Water treatment and test results

^a HMN or HMN/n-heptane [1]Applied by dipping

To ensure that the polymerization reaction was mainly carried out, the plasma treatment process was carried out with an n-heptane/Ar (1). It was found that a water-repellent function was obtained by using n-heptane/Ar with a contact angle of 112 ° (FIG. 6).

To optimize the waterproofing function using HMN, various HMN concentrations were applied and the results are shown in fig. 9. It was found that 10% HMN (volume percent) in n-heptane, i.e. HMN/n-heptane [ 10. In addition, an optimized treatment time was also determined, which was 1min; this enables the water repellency to be maintained after a single wash with detergent (fig. 10). Although the optimum reaction conditions using HMN have been determined, the wash durability (less than 5 washes) and hand after treatment are not very satisfactory.

iii methylhydrogensiloxane

Methyl hydrogen siloxane, also called polymethylhydrosiloxane, is a water repellent and softening agent. It is oil soluble and can be diluted with solvents such as acetone, ethyl acetate, etc., or with water in the presence of an emulsifier. The methylhydrogensiloxane coating is thermally cured at elevated temperatures (e.g., 150 ℃ C., 15 MIN); the curing process is accelerated by the use of catalysts including zinc octoate, iron octoate, dibutyltin dilaurate, and tin octoate.

The plasma treatment process may be performed at room temperature without using a catalyst. The water repellent treatment with different concentrations of methylhydrogensiloxane (0.25% -3%) was investigated and all treated samples still showed significant water repellency after five successive washes with household laundry equipment and detergent (fig. 11).

The wash durability of these treated samples was further evaluated according to AATCC test method 61-2010, condition 2A, where each wash corresponded to 5 low temperature machine washes repeated at home (fig. 12). Using this test method, cotton fabric was cut into 50mm by 150mm pieces and washed in a rotating closed tank containing 150ml of an aqueous solution of AATCC standard WOB detergent (0.15%, w/v) and 50 stainless steel balls, with a thermostatic water bath controlled at 49 ℃ and a rotational speed of 40. + -.2 rpm for 45min. When the concentration of the methyl hydrogen siloxane is lower than 0.5 percent (volume percentage), the waterproof function can not be maintained after two times of accelerated clothes washing; and when the concentration of the methyl hydrogen siloxane is more than 0.75 percent, the function can be still maintained after four times of washing.

In addition, heat curing of the 2% methylhydrogensiloxane coating at 160 ℃ for 30min also achieved a water-repellent function, but the functional coating completely disappeared after the second wash (fig. 13). These results clearly show that plasma treatment can improve the wash durability of the coating.

Optimized reaction conditions for water repellent treatment 1% methylhydrogensiloxane was used and treated with Ar plasma at power =400W for 1min. The water repellent treatment under optimized conditions was performed on cotton and wool fabrics. The effect of the water repellent function and plasma treatment on physical properties including color change, breathability and hand was studied.

The formation of the coating was confirmed by SEM imaging, and the result is shown in fig. 7. The results clearly show that a smooth and uniform deposit was formed on the plasma treated wool and cotton fibers, whereas such deposits were not observed on those untreated samples.

The water contact angle for both the plasma treated cotton and wool samples was 102 ° (fig. 8), which clearly shows that sufficient hydrophobicity was obtained. The water resistance of the cotton and wool samples was further confirmed by the spray test (AATCC 22), which was grade 90 in this test (table 10). After 20 washing cycles (ISO 6330.

TABLE 10 spray test results for plasma treated wool and cotton fabrics (AATCC 22)

Remarks for note

Washing conditions are as follows: 20 cycles according to ISO 6330; test procedure 4N,40 ℃ roller drying (drum dry delay);

grade 90: slight random adhesion or wetting of the upper surface;

grade 80: the upper surface is wetted at the spray point.

The effect of plasma treatment on physical properties was investigated. The color of both cotton and wool samples did not change significantly (table 11). The air permeability of the wool sample was found to decrease and the air permeability of the cotton sample was slightly increased. On the other hand, a fabric touch test was performed, and the results are shown in table 12. Finally, no harmful chemicals were found in the treated samples, including formaldehyde, chlorinated phenols, short-chain chlorinated paraffins, etc., and the results are shown in table 13.

TABLE 11 color change (AATCC evaluation program 1-2007) and air permeability (ASTM D737) test results for plasma treated wool and cotton fabrics

Remarks for note

Color change/coloration

Grade 5 negligible or no color change/coloration

Grade 4 slight color change/coloration

TABLE 12 Fabric touch test results for plasma treated wool and cotton fabrics

Remarks for note

Due to the size limitations of plasma machines, the samples used for fabric touch testing are smaller than required and the results may not be reliable.

TABLE 13 hazardous chemical test results for plasma treated fabrics

Conclusion

Functional treatments using plasma technology under different conditions were investigated by varying the pressure, time and coating material dose.

The water repellency of the treated fabrics was evaluated by measuring the contact angle and spray test (AATCC 22). Cotton and wool fabrics have been found to be successful in providing water-resistance. The optimized treatment conditions capable of withstanding 20 washes industrially were found to be 1% methylhydrogensiloxane and treatment with Ar plasma at power =400W for 1min.

Reference:

[1]Y.Gao and R.Cranston,“Recent Advances in Antimicrobial Treatments of Textiles”,Textile Research Journal,2008,78,60.

[2]S.-H.Hsieh,Z.K.Huang,Z.Z.Huang and Z.S.Tseng,“Antimicrobial and Physical Properties of Woolen Fabrics Cured with Citric Acid and Chitosan”, Journal of Applied Polymer Science,2004,94,1999.

[3]A.Cuesta and J.M.D.Tascon,“Shrinkage Properties of Wool Treated with Low Temperature Plasma andChitosan Biopolymer”,Textile Research Journal,1999, 69,811.

[4]J.Yua,Z.Pang,J.Zhang,H.Zhou and Q.Wei,“Conductivity and Antibacterial Properties of Wool Fabrics Finished by Polyaniline/Chitosan”,Colloids and Surfaces A,2018,548,117.

Claims

1. A fabric with a coating, characterized in that the coating comprises the following coating material: 2,2,4,4,6,8,8-heptamethylnonane; and the coating is subjected to plasma treatment before or after coating; the plasma treatment process is carried out with a gas flow of n-heptane/Ar in a volume ratio of 1:1; when the coating material is 2,2,4,4,6,8,8-heptamethylnonane, its concentration in n-heptane is 10%.

2. The fabric according to claim 1, characterized in that the fabric is selected from cotton fabric and/or wool fabric.

3. The fabric according to claim 1, characterized in that the plasma treatment is performed one or more times.

4 . The fabric according to claim 1 , wherein the plasma treatment is performed under a pressure of 5×10 ⁰ Pa to 8×10 ² Pa.

5. The fabric according to claim 1, characterized in that the fabric is treated with 2,2,4,4,6,8,8-heptamethylnonane for 1 minute.