CN112301725A

CN112301725A - Waterproof fabric obtained by plasma technology and preparation method thereof

Info

Publication number: CN112301725A
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: 2021-02-02
Anticipated expiration: 2039-08-02
Also published as: CN112301725B; WO2021023120A1

Abstract

The invention relates to a waterproof fabric obtained by plasma technology and a preparation method thereof. The plasma technology treatment of the present invention is applied only to the surface, and the overall properties of the material can be maintained, and the waterproof fabric obtained therefrom sometimes has waterproof performance after washing.

Description

Waterproof fabric obtained by plasma technology and preparation method thereof

Technical Field

The invention relates to a waterproof fabric obtained by plasma technology and a preparation method thereof.

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 1:5, while the drum method requires less water where MLR is less than 1: 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 treatments are only applied to the surface and therefore 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, 2,4,4,6,8, 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 5x 10⁰Pa to 8x 10²Pa. The plasma treatment time may be 1-10 min.

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) plasma treating the fabric with hexamethyldisiloxane 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, HHMDSO plasma pretreatment, with a power of 100W, typically the plasma treatment time of the coating material is greater than 2 min; the plasma treatment time of the coating material is more than 5min at a power of 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 is coated by treating the fabric with 2,2,4,4,6,8, 8-heptamethylnonane for 1 minute.

According to some embodiments, when the coating material is methylhydrosiloxane, 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

FIG. 1 SEM image of HMDSO coated on cotton fabric.

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

FIG. 3 is an SEM image of a waterproof layer 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.

Fig. 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) wool fibers treated with HMDSO plasma 100W for 2min, (c) wool fibers treated with HMDSO plasma 100W for 8min, (d) wool fibers treated with HMDSO plasma 100W for 20min

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

FIG. 9 Water repellent treatment of Cotton Fabric with varying concentrations of 2,2,4,4,6,8, 8-Heptamethylnonane (HMN) and a continuous stream of n-heptane/Ar [ P ═ 400W ]

Fig. 9 (continuous.) cotton fabric was waterproofed with varying concentrations of 2,2,4,4,6,8, 8-Heptamethylnonane (HMN) and a continuous stream of n-heptane/Ar [ P ═ 400W ]

Fig. 10. continuous flow with 2,2,4,4,6,8, 8-Heptamethylnonane (HMN) and n-heptane/Ar [ HMN/n-heptane ═ 10: 90; P-400W for water-proof treatment of cotton fabric

Fig. 11. water-repellent treatment of cotton fiber using methylhydrogensiloxane [ Ar plasma treatment, power 400W, time 1min ] at various concentrations, and washing five times consecutively using household laundry equipment and detergent fig. 12. water-repellent treatment of cotton fiber using methylhydrogensiloxane [ Ar plasma treatment, power 400W, time 1min ] (laundry method: AATCC test method 61-2010, condition 2A)

Fig. 12 (continuation 1) waterproof-treatment of cotton fibers 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) waterproof-treatment of cotton fibers 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 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 10⁰Pa to 8x 10²Pa
		Time of treatment	0.5min to 10min
Power of	Maximum 400W
		Temperature of	At room temperature

II. Material

The wool fabric is 100% merino wool, the single-sided knitted fabric has the weight of 265g/m²The 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/m²The structure is 48 needles per inch in the longitudinal direction and 30 needles per inch in the transverse direction; and ii) a cleaned and bleached plain weave fabric having a fabric weight of 265g/m². 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: 2012. 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 45 min. A single washing cycle of 45min corresponds to 5 domestic washing cycles. In ISO6330, 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 fabric was washed in a 40 ℃ drum washer for 1min and rinsed 2 times, then dried flat and repeated 20 times. Ii) water resistance

Water repellency was evaluated 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 an 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 Water repellent treatment of Cotton Fabric Using 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

^aAATCC22 water-proofing: 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 washing. 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.2,2,4,4,6,8, 8-Heptamethylnonane (HMN)

Hydrocarbon-based

waterproofing agents

2,2,4,4,6,8, 8-Heptamethylnonane (HMN) were also investigated under various reaction conditions (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 conditions and test results for the repellent treatment of cotton fabrics with 2,2,4,4,6,8, 8-Heptamethylnonane (HMN)

Reagent	Power of	Temperature of	Time of day	Water-proof property
					HMN	15W	70℃	5min	Is free of
HMN	15W	70℃	10min	Is free of
					HMN	30W	70℃	5min	Is free of
HMN	30W	70℃	10min	Is free 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 free 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

^aHMN applied by dipping

^bHMN/n-heptane [1:1 ]]Applied by dipping

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

Conditions and test results of Water treatment

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

To ensure that the polymerization reaction was mainly carried out, the plasma treatment process was carried out with a flow of n-heptane/Ar (1:1) gas, and the plasma was applied in a pulsed manner, with the results shown in Table 4. 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 [10:90], showed the best water resistance. In addition, an optimized treatment time of 1min was also determined; 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 high 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 studied 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 at 40 + -2 rpm for 45 min. 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 1 min. 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 (AATCC22), which was grade 90 in this test (table 10). After 20 wash cycles (ISO 6330:2012), the water resistance of both samples remained grade 80 in the spray test.

TABLE 10 spray test results (AATCC22) for plasma treated wool and cotton fabrics

Remarks for note

Washing conditions are as follows: 20 cycles according to ISO 6330: 2012; test procedure 4N, 40 ℃, drum dry (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 optimum treatment conditions found to be able to withstand 20 washes in the industry were 1% methylhydrogensiloxane and treatment with an Ar plasma at a power of 400W for 1 min.

Reference documents:

[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 having a coating, characterized in that the coating comprises a coating material selected from the group consisting of: hexamethyldisiloxane, 2,4,4,6,8, 8-heptamethylnonane or methylhydrogensiloxane; and the coating is plasma treated before or after coating.

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

3. A method of making a fabric according to claim 1 or 2, wherein the fabric is subjected to a step of applying a coating material selected from the group consisting of: hexamethyldisiloxane, 2,4,4,6,8, 8-heptamethylnonane or methylhydrogensiloxane.

4. The method of claim 3, wherein the plasma is selected from one of nitrogen, argon, oxygen, n-heptane, and air, or any combination thereof.

5. A method according to claim 3 or 4, characterized in that the plasma treatment is carried out one or more times.

6. The method according to any one of claims 3 to 5, wherein the plasma treatment is at a pressure of 5x 10⁰Pa to 8x 10²Pa, and the like.

7. A method according to any one of claims 3 to 6, characterized in that, when the coating material is hexamethyldisiloxane, the method comprises the following two steps:

i) treating the fabric with Ar plasma; and

ii) pre-treating the fabric with a hexamethyldisiloxane plasma to form a coating on the fabric surface.

8. The method of claim 7, further comprising introducing a coupling agent to the surface of the fabric.

9. A method according to any of claims 3 to 5, characterized in that when the coating material is 2,2,4,4,6,8, 8-heptamethylnonane, its concentration in n-heptane is 10%.

10. The method of claim 9, comprising treating the fabric with 2,2,4,4,6,8, 8-heptamethylnonane for 1 minute.

11. The method according to any one of claims 3 to 5, wherein when the coating material is methylhydrogen siloxane, the concentration of the methylhydrogen siloxane is 0.5% -2%.

12. The method according to claim 11, wherein the concentration of the methylhydrogensiloxane is 0.75% to 1.5%.

13. The method according to claim 10, wherein the concentration of methylhydrogensiloxane is 1%.

14. The method of claim 13, comprising using 1% methylhydrogensiloxane, a plasma power of 400W, and an argon plasma treatment for 1-2 minutes.

15. The method according to any one of claims 11 to 14, wherein in the coating step a catalyst selected from the group consisting of: zinc octoate, iron octoate, dibutyltin dilaurate, and tin octoate.