Water-Repellent Textile

The present invention relates to a water-repellent textile subjected to water-repellent treatment.

In pursuit of a healthy, fashionable and natural life, more and more people are heading outdoors. For outdoor sportswear fabrics, people expect them to have excellent water repellency.

At present, water repellents used for water-repellent finishing are mainly divided into two categories: fluorinated water repellents and non-fluorinated water repellents. Although textiles treated with fluorinated water repellents have advantages such as high water repellency and high washing resistance, an ammonium perfluorooctanoate (hereinafter referred to as PFOA) and perfluorooctane sulfonate compound (hereinafter referred to as PFOS) contained in the fluorinated water repellents are genotoxic and reproductive toxic, and are difficult to biodegrade, which is not conducive to environmental protection. For example, Chinese patent document CN106758252A discloses a water and oil proofing agent convenient for maintenance, a preparation method thereof, and a textile, and specifically discloses a textile processed with a water and oil proofing agent containing polyurethane, wherein the polyurethane is obtained by reacting polyisocyanates, fluorosilicone polyols, silicon-containing polyols, other polyols and sealants. The textile finished with the water and oil proofing agent has better water and oil proofing effects and washing resistance. However, the water and oil proofing agent contains fluorinated compounds, and thus does not meet environmental protection requirements.

A water-repellent fabric processed with an environmentally-friendly non-fluorinated water repellent has excellent initial water repellency and durability after being washed for 10 times (or 30 times), but the water repellency decreases significantly after being washed for more times, such as 100 times. For example, Chinese patent document CN105734970A discloses a textile subjected to water-repellent treatment and a production method thereof, and specifically discloses that the surface of a single fiber of the textile is covered with a resin film, and a main component of the resin film is a non-fluorinated compound. Based upon the measurement according to the JIS L 1092 spray method criteria, this textile has a water repellency of level 3 or above after being washed for 10 times, but the problem of decreased water repellency after more washing times cannot be solved. In addition, Japanese patent document laid-open 2019-173185 discloses a water-repellent composition for fibers and a water-repellent fiber product, wherein the water-repellent composition includes a component (A), silicone resin (B) and water, the component (A) being at least one of a carbamate compound (A1), acrylic resin (A2) and reactive silicone (A3). The fiber product processed with the water repellent has a water repellency of only level 3 after being washed for 5 times, and the problem of decreased water repellency after more washing times is also not solved.

An object of the present invention is to provide an environmentally-friendly textile having better water repellency and washing durability.

In order to achieve the above object, the technical solution of the present invention is as follows:

In the water-repellent textile of the present invention, the surface of its single fiber is covered with a resin film with a specific thickness, and main components of this resin film are a non-fluorinated water-repellent compound and an isocyanate compound. On the one hand, such a resin film can make it difficult for water molecules to penetrate, thereby obtaining excellent initial water repellency; on the other hand, in addition to reacting with the non-fluorinated water-repellent compound, the isocyanate compound in the resin film can also react with the fiber to make the non-fluorinated water-repellent compound firmly attached to the single fiber, thereby improving the washing durability. In addition, compared with fluorinated compounds, the non-fluorinated compound is safe and more environmentally friendly.

The present invention provides a water-repellent textile, wherein the surface of a single fiber constituting this water-repellent textile is covered with a resin film with a thickness of 60 to 100 nm. This is because if the thickness of the resin film is less than 60 nm, after multiple washes, especially 100 washes, the resin film will be severely damaged and the textile will not have super-high washing durability; and if the thickness of the resin film is greater than 100 nm, the effective components are already saturated and the water repellency cannot be further improved, which will affect the hand feel and increase the cost. Preferably, the thickness of the resin film is 70 to 90 nm. This is because within this range, the textile has particularly excellent washing durability and good hand feel.

In the present invention, main components of the resin film are a non-fluorinated water-repellent compound and an isocyanate compound. The non-fluorinated water-repellent compound can form a film on the single fiber, which can give the textile good water repellency, while isocyanate groups in the isocyanate compound can not only react with the non-fluorinated water-repellent compound, but also react with the fiber to make the non-fluorinated water-repellent compound firmly attached to the single fiber, thereby significantly improving the washing durability.

Preferably, the isocyanate compound in the resin film of the present invention is a polymer formed from aromatic multifunctional isocyanates and polyols. The above-mentioned polymer has a network structure, which can lock the non-fluorinated water-repellent compound more firmly, making it less likely to fall off, and further improving the washing durability.

The polyols herein are not particularly limited and may be diols and/or triols. The polyol preferably has a structure shown in formula 1:

This is because the polyol containing the structure of Formula 1, due to its terminal groups —OH and -M, easily reacts with aromatic multifunctional isocyanate to form chemical bonds, making the formed network structure more compact, thereby locking the non-fluorinated water-repellent compound more firmly in the network structure, making it less likely to fall off, and further improving the washing durability.

Preferably, the non-fluorinated water-repellent compound is a hydrocarbon compound, a polysiloxane compound A or a copolymer thereof.

The hydrocarbon compound is not particularly limited, and may be an acrylate compound, a stearate compound, an N-hydroxymethyl compound, or the like. Examples of the acrylate compound include butyl acrylate, acrylonitrile, acrylamide, etc.; examples of the stearate compound include sodium stearate, calcium stearate, aluminum stearate, etc.; and examples of the N-hydroxymethyl compound include etherified hexamethylol melamine, N-Hydroxymethyloctadecamide, etc. The hydrocarbon compound can enhance the interaction between emulsion particles and water molecules, which is beneficial to the formation of dense cross-linked structures, and can improve the film-forming strength while being self-polymerized into a film on the surface of the single fiber.

When the hydrocarbon compound is an acrylate compound, a water-repellent film formed by this compound has better uniformity, making water molecules difficult to penetrate, and has certain stiffness to withstand the impact of external forces (washing or friction rubbing, etc.), and is thus not easy to fall off. Preferably, the hydrocarbon compound is an acrylate compound having a structural unit shown in formula 2,

Due to its low molecular weight, the polysiloxane compound A is easy to enter the fiber, and a film formed on the surface of this compound can reduce the friction coefficient between yarns, thereby improving the hand feel. Preferably, the polysiloxane compound A is a compound having a structure shown in formula 3,

Preferably, the resin film of the present invention includes a flexible compound, and the flexible compound is a polyethylene compound and/or a polysiloxane compound B. This compound can make the film formed on the fiber surface have lower surface tension and smoothness, reduce the friction coefficient between fibers, and improve the hand feel.

The polysiloxane compound B is not particularly limited, but preferably has a structural unit shown in formula 4,

Preferably, the thickness of the resin film of the water-repellent textile of the present invention is 40 to 100 nm after being washed for 100 times according to the method 103 in JIS L 0217:1995 criteria or the method C4M in JIS L 1930:2014 criteria.

Preferably, the water-repellent textile of the present invention has an initial water repellency of level 4 or above according to a test using the spray method in JIS L 1092:2009 criteria.

Preferably, the water-repellent textile of the present invention has a water repellency of level 3 or above after being washed for 100 times according to the method 103 in JIS L 0217:1995 criteria or the method C4M in JIS L 1930:2014 criteria, and then tested according to the spray method in JIS L 1092:2009 criteria.

The fiber raw material of the water-repellent textile of the present invention is not particularly limited, and may be composed of cellulose fiber and/or synthetic fiber. The cellulose fibers herein include natural cellulose fibers and regenerated cellulose fibers. Wherein, examples of the natural fibers include cotton fibers, hemp fibers, etc.; examples of the regenerated cellulose fibers include viscose fibers, modal fibers, etc.; and examples of the synthetic fibers include polyester fibers (PET), polyamide fibers, polyacrylonitrile fibers, etc.

The water-repellent textile of the present invention may be a woven fabric or a knitted fabric. The weaves of the woven fabric are not particularly limited, and may include plain weave, twill weave, satin weave, etc. The weaves of the knitted fabric are not specifically limited, and may include weft plain weave, ribbing weave, double reverse weave, warp plain weave, and warp satin, etc.

A preparation method of the water-repellent textile of the present invention is not particularly limited, and may be prepared by the following method: pre-treatment of grey cloth (desizing and degreasing), intermediate shaping, dyeing (optional), and post-finishing to obtain the product of the present invention.

Wherein, the post-finishing process preferably uses a processing solution containing the following components for dipping and padding processing, which is then dried at a temperature of 80 to 150° C., and finally subjected to shaping finishing at 130 to 200° C.

The dipping and padding solution is composed of the following components:

The gram weight of the grey cloth here is preferably 50 to 300 g/m. If the gram weight of grey cloth is less than 50 g/m, the requirements for the weaving process are relatively high, and yarn breakage may occur, which is not conducive to production, so this grey cloth is not preferred; and if the gram weight of grey cloth is greater than 300 g/m, it may affect wearing comfort, so this grey cloth is not preferred.

The water repellent herein is a non-fluorinated water repellent, and its type is not particularly limited, and is preferably one or more of a hydrocarbon compound, a paraffin compound, and a polysiloxane compound A. The amount of the water repellent is preferably 40 to 100 g/L. When the amount of a water repellent is less than 40 g/L, it is difficult to form a uniform water-repellent film on the fiber surface, so this water repellent is not preferred due to poor water repellency; and when the amount of a water repellent is greater than 100 g/L, effective components covering the fiber surface are already saturated, and the water repellency cannot be further improved, which will affect the hand feel and increase the cost, so this water repellent is not preferred.

The type of the crosslinker is not particularly limited, but is preferably blocked isocyanate, and more preferably a polymer of aromatic polyfunctional isocyanate and polyol. The amount of the crosslinker is preferably 10 to 40 g/L. When the amount of a crosslinker is less than 10 g/L, reactive groups that can react with the water repellent and attach to the fiber surface are relatively few, and after multiple washes, especially after 100 washes, a large amount of isocyanate attached to the water repellent falls off, so the textile cannot have super-high washing durability, and is therefore not preferred; and when the amount of a crosslinker is greater than 40 g/L, effective components that can react with the water repellent are already saturated, and the washing durability cannot be further improved, but the hand feel will be affected, and the cost will also be increased, so this crosslinker is not preferred.

The type of the softener is not particularly limited, but is preferably a polyethylene compound and/or a polysiloxane compound B. The amount of the softener is preferably 10 to 30 g/L. When the amount of a softener is less than 10 g/L, it is difficult to form a uniform soft film on the fiber surface, and to improve the hand feel, so this softener is not preferred; and when the amount of a softener is greater than 30 g/L, the effect of improving the hand feel is not obvious, and the water repellency of the textile possibly decreases, so this softener is not preferred.

The type of the penetrant here is not particularly limited, but is preferably isopropanol and/or aliphatic ethoxylated alcohol. The amount of the penetrant is preferably 10 to 20 g/L. When the amount of a penetrant is less than 10 g/L, It is difficult for a agent to penetrate into the fibers, and it is difficult to form a uniform water-repellent film between the fibers, which makes it possible for water molecules to enter and affect the water repellency, so this penetrant is not preferred; and when the amount of a penetrant is greater than 20 g/L, active components are already saturated, and the cost will be increased, so this penetrant is not preferred.

The above-mentioned agents may be commercially available or synthesized according to the known techniques in the art.

This is because the water repellent can form a film at a drying temperature of ≥80° C. to produce a water-repellent effect; and the crosslinker undergoes a chemical reaction at a setting temperature of more than 130° C. and firmly adheres to the textile, making the textile both water-repellent and wash-resistant.

A method for preparing a processing solution is not particularly limited and may be carried out as follows: a water repellent and a crosslinker are added in sequence, further added with a softener if the hand feel needs to be improved, added with water for blending, and stirred continuously, but the stirring speed should not be too fast to avoid demulsification. A processing agent used in actual processing and its amount need to be adjusted according to different textiles to be processed. At the same time, local adjustments should be made to the processing method in a timely manner to ensure that the processing solution can fully play its role and improve the properties of the textiles.

The present invention will be further described below with reference to the examples and comparative examples.

Various physical property parameters involved in the present invention are tested according to the following method.

A piece of sample cloth having a size of 1 cm×1 cm was taken, and cut along a position perpendicular to a warp or weft direction of the textile to obtain a cross section, and then the following equipment was used to observe the thickness of the resin film deposited on the surface of the textile on the cross section to be tested. One of the equipment was selected as needed for measurement.

The operating method referred to JY/T 010-1996 “General Rules for Analytical Scanning Electron Microscopy Methods”.

The operation method referred to KS D 8544-2006 “Metallic Coatings. Coating Thickness Measurement. Transmission Electron Microscopy Method”.