WO2025154271A1 - Water-repellent treatment agent for fibers, water-repellent fiber product, and method for producing water-repellent fiber product - Google Patents

Abstract

The purpose of the present invention is to provide: a water-repellent treatment agent for fibers capable of performing, in supercritical carbon dioxide, water-repellent finishing that realizes less pot stain and sufficient water-repellent performance and washing durability (therefore, durable water repellency), even though a silicone-based compound is used therein; a water-repellent fiber product treated with said water-repellent treatment agent for fibers; and a method for producing said water-repellent fiber product. One embodiment of the present invention provides a water-repellent treatment agent for fibers, in which a silicone resin including M units is contained in supercritical carbon dioxide.

Description

Water-repellent treatment agent for textiles, water-repellent textile product, and method for producing water-repellent textile product

The present invention relates to a water-repellent treatment agent for textiles, a water-repellent textile product, and a method for producing a water-repellent textile product.

　Conventionally, fluorine-based water repellents and silicone-based water repellents have been used as textile water repellents in processing to improve the water repellency of textiles in supercritical carbon dioxide.

Fluorine-based water repellents are generally manufactured by polymerizing or copolymerizing monomers that have a fluoroalkyl group. Although textile products treated with fluorine-based water repellents exhibit excellent water repellency, monomers that have a fluoroalkyl group are difficult to decompose, which poses environmental problems. In recent years, research has been conducted into non-fluorine-based water repellents that do not contain fluorine.

Patent Document 1 describes a fiber treatment agent that is characterized in that a fluorine-based compound and/or a silicone-based compound is contained in a supercritical fluid or a similar fluid, and also describes that the supercritical fluid or a similar fluid may use carbon dioxide as a medium.

Patent Document 2 describes a method for imparting functionality to a fiber structure, characterized in that when a functional agent is applied to the fiber structure in a supercritical fluid, the functional agent is applied while circulating the supercritical fluid.

JP 2000-220074 A JP 2002-212884 A

In the technology described in Patent Document 1, water-repellent processing is carried out using a silicone compound, methylhydrogenpolysiloxane, with a molecular weight of 10,000. However, this silicone compound can cause stains on the kettle (container) in which the water-repellent processing is carried out. This technology is not practical because it is difficult to clean the inside of the kettle when using large water-repellent processing equipment to produce water-repellent textile products.

In the technology described in Patent Document 2, dimethylpolysiloxane with a molecular weight of 10,000 is used as a functional agent, and the dimethylpolysiloxane is attached to a fiber structure in supercritical carbon dioxide. However, this method can also cause pot fouling, and is not practical for producing water-repellent fiber products using large water-repellent processing equipment.

The present invention was made in consideration of the above technical problems, and aims to provide a water-repellent treatment agent for fibers that enables water-repellent processing to be performed in supercritical carbon dioxide that reduces pot staining and achieves sufficient water-repellent performance and washing durability (hence durable water repellency) despite the use of a silicone-based compound; a water-repellent fiber product treated with said water-repellent treatment agent for fibers; and a method for manufacturing said water-repellent fiber product.

The inventors conducted extensive research to achieve the above objective, and as a result, completed the invention described below.

One aspect of the present invention provides a water repellent treatment agent for fibers, which comprises a silicone resin containing M units contained in supercritical carbon dioxide.

Another aspect of the present invention provides a water-repellent textile product treated with the water-repellent textile treatment agent.

Another aspect of the present invention is a method for producing a water-repellent textile product, comprising the steps of:
and treating a substrate with the water repellent treating agent for fibers to obtain a water repellent fiber product.
The present invention provides a method for producing a water-repellent textile product, in which the above treatment is carried out under conditions in which the temperature of the supercritical carbon dioxide is in the range of 40°C to 130°C.

The present invention can provide a water-repellent treatment agent for textiles that enables water-repellent processing to be performed in supercritical carbon dioxide, which reduces pot staining and achieves sufficient water-repellent performance and washing durability (hence durable water repellency), despite the use of a silicone-based compound; a water-repellent textile product treated with the water-repellent treatment agent for textiles; and a method for producing the water-repellent textile product.

Below, exemplary embodiments of the present invention are described in detail. However, the present invention is not limited to the following embodiments.

<Water repellent treatment for textiles>
The water repellent treatment agent for fibers of this embodiment contains a silicone resin that includes M units.

[[Silicone resin containing M units]]
A silicone resin containing M units is a silicone that contains M units and is a resin. In this disclosure, "silicone resin" means a silicone that has a three-dimensional network structure and is a solid at 25°C (i.e., has a melting point above 25°C).

Silicone resins containing M units preferably contain MQ, MDQ, MT, MTQ, MDT or MDTQ as constituent units. That is, as silicone resins containing M units, MQ resin, MT resin or MDT resin is generally known. Silicone resins containing M units may have a portion indicated as MDQ, MTQ or MDTQ. Here, M, D, T and Q are (R'') ₃ SiO _0.5 unit, (R'') ₂ SiO unit, R''SiO _1.5 unit and SiO ₂ unit, respectively (wherein R'' is a monovalent organic group). In one embodiment, R'' is a monovalent hydrocarbon group, preferably a monovalent aliphatic hydrocarbon group having 1 to 10 carbon atoms or a monovalent aromatic hydrocarbon group having 6 to 15 carbon atoms. Suitable examples of the (R'') group are methyl group, ethyl group, benzyl group, phenyl group and the like. The (R'') groups present in the silicone resin containing M units may be of one type or of two or more types.

Silicone resin has a three-dimensional network structure, which is believed to give it low fluidity, which is believed to provide the advantage that the attached drug is less likely to fall off the substrate.
In addition, when a silicone resin contains M units, it is believed that the organic groups, which are hydrophobic groups, are oriented in large numbers on the outermost surface of the particles, and therefore it is believed that the silicone resin has the advantage of exhibiting better water repellency than a silicone resin that does not contain M units.

For example, the silicone compounds described in Patent Documents 1 and 2 are thought to have a weak adhesive force to the fabric. In other words, even if the agent adheres to the fabric once in supercritical carbon dioxide, it is thought that the agent is likely to detach and adhere to the inside of the kettle (and therefore the kettle is likely to become soiled). On the other hand, the silicone resin of this embodiment is thought to have a strong adhesive force to the fabric. In other words, it is thought that the agent is unlikely to remain in the kettle (and therefore the kettle is unlikely to become soiled) because it is unlikely to detach from the fabric.

In a silicone resin containing M units, the monovalent groups bonded to silicon atoms in one embodiment contain a hydrocarbon group, and optionally further contain any of hydrogen, amino groups, halogens (e.g., chlorine and bromine), alkoxy groups, etc. From the viewpoint of affinity with supercritical carbon dioxide, the ratio of hydrocarbon groups out of the total number of monovalent groups bonded to silicon atoms (100%) is preferably 50% or more, or 70% or more, or 90% or more, or may be 100%.

In a silicone resin containing M units, the ratio of M units to 100 mol% of all constituent units is, from the viewpoint of water repellency, preferably 10 mol% or more, or 20 mol% or more, or 30 mol% or more, and preferably 90 mol% or less, or 80 mol% or less, or 70 mol% or less.
The molecular structure of the silicone resin can be confirmed by methods such as nuclear magnetic resonance (NMR) and X-ray photoelectron spectroscopy (XPS).

The silicone resin containing M units contained in the water repellent treatment agent for fibers may be one type or two or more types. For example, a combination of MQ resin and MT resin may be used. From the viewpoint of water repellency, MQ resin is more preferable among silicone resins containing M units. In one embodiment, the MQ resin may have M units at the molecular terminals and Q units at the sites other than the molecular terminals.

Silicone resins containing M units can be obtained alone or as a solution in which they are dissolved in alkyl polysiloxanes and/or suitable solvents other than alkyl polysiloxanes. Examples of solvents other than alkyl polysiloxanes include n-hexane, isopropyl alcohol, methylene chloride, 1,1,1-trichloroethane, and mixtures thereof.

Examples of solutions in which silicone resins containing M units are dissolved in alkylpolysiloxane include KF7312J (a mixture of trimethylsilyl-containing polysiloxane and decamethylcyclopentasiloxane = 50:50 (mass ratio)), KF7312F (a mixture of trimethylsilyl-containing polysiloxane and octamethylcyclotetrasiloxane = 50:50 (mass ratio)), KF9021L (a mixture of trimethylsilyl-containing polysiloxane and low-viscosity methylpolysiloxane = 50:50 (mass ratio)), and KF7312L (a mixture of trimethylsilyl-containing polysiloxane and low-viscosity methylpolysiloxane = 50:50 (mass ratio)) commercially available from Shin-Etsu Chemical Co., Ltd.

Examples of silicone resins containing M units include MQ-1600 solid resin (trimethylsilyl group-containing polysiloxane) and MQ-1640 flake resin (a mixture of trimethylsilyl group-containing polysiloxane and polypropylsilsesquioxane), both of which are commercially available from Toray Dow Corning Co., Ltd. The above commercially available products contain trimethylsilyl group-containing polysiloxane, and include MQ, MDQ, MT, MTQ, MDT, or MDTQ.

The hardness of the silicone resin containing M units, measured with a type A durometer in accordance with JIS K 6249:200313. Hardness test, is preferably 20 or more, more preferably 60 or more, from the viewpoint of water repellency. In one embodiment, the above hardness may be 80 or less, or 70 or less, from the viewpoint of affinity with supercritical carbon dioxide.

The weight average molecular weight of the silicone resin containing M units is preferably 1,000 or more, or 2,000 or more, or 3,000 or more, or 4,000 or more from the viewpoint of water repellency, and is preferably 50,000 or less, or 45,000 or less, or 40,000 or less from the viewpoint of affinity with supercritical carbon dioxide. The weight average molecular weight is a polystyrene-equivalent molecular weight calculated from a GPC curve (elution curve) obtained by gel permeation chromatography (GPC). As the solvent used in the GPC measurement, any solvent may be used, such as tetrahydrofuran, as long as it is capable of dissolving the sample. As the solvent for the mobile phase, any solvent may be used, such as tetrahydrofuran, as long as it is capable of dissolving the sample. The column is filled with gel particles such as styrene-divinylbenzene. The size of the gel particles packed in the column may be selected to match the molecular weight range to be measured.

The amount of silicone resin containing M units in the water repellent treatment agent for fibers relative to the total of 100% by mass of components other than supercritical carbon dioxide is preferably 50% by mass or more, 70% by mass or more, or 80% by mass or more, from the viewpoint of obtaining good water repellency, and may be 100% by mass.

The amount of silicone resin containing M units relative to the total amount of 100% by mass of the water repellent treatment agent for fibers is preferably 0.0006% by mass or more, or 0.006% by mass or more, or 0.03% by mass or more, from the viewpoint of obtaining good water repellency performance, and is preferably 3.0% by mass or less, or 2.5% by mass or less, or 2.0% by mass or less, from the viewpoint of suppressing pot fouling by allowing a desired amount of supercritical carbon dioxide to be present.

In the water repellent treatment agent for fibers, the amount of silicone resin containing M units per 100 ml of supercritical carbon dioxide is preferably 0.00035 g or more, or 0.0035 g or more, or 0.0175 g or more from the viewpoint of obtaining good water repellency performance, and is preferably 0.7 g or less, or 0.525 g or less, or 0.35 g or less from the viewpoint of suppressing pot staining. Note that the above amounts are values at the temperature and pressure when the water repellent treatment agent for fibers is applied to the fibers.

[Supercritical carbon dioxide]
The water repellent treatment agent for fibers of this embodiment contains a silicone resin containing M units in supercritical carbon dioxide. Supercritical carbon dioxide is carbon dioxide that exists in a supercritical state, that is, as a supercritical fluid that has properties of both a gas and a liquid.
Silicone resins containing M units may be difficult to dissolve and/or disperse in liquid media due to their three-dimensional network structure, but they can be easily dissolved and/or dispersed in supercritical carbon dioxide. That is, by using supercritical carbon dioxide as a medium when applying silicone resins containing M units to water-repellent textile products, it is possible to make the silicone resins containing M units exist in the medium in a desired amount, for example, a relatively large amount. In addition, by using supercritical carbon dioxide as a medium, it is possible to simplify the solvent removal process required, for example, when using a liquid medium. That is, supercritical carbon dioxide is easily vaporized by pressure drop, so it can be easily removed in a short and simple process.
Although various molecules other than carbon dioxide are known to constitute supercritical fluids, carbon dioxide is particularly suitable as a medium for silicone resins containing M units because it is non-polar and therefore capable of dissolving many drugs, it has a lower critical point than other substances and can be brought into a supercritical fluid state relatively easily, and it is non-toxic.
The method for producing supercritical carbon dioxide and the method for incorporating a silicone resin containing M units into supercritical carbon dioxide will be described later in the section entitled "Method for producing water-repellent textile products."

[Other ingredients]
The water repellent treatment agent for fibers of this embodiment may further contain, in addition to the silicone resin containing M units and supercritical carbon dioxide described above, a silicone resin not containing M units, various organic solvents, antibacterial and antiviral agents, antifungal agents, dyes, pigments, deodorants, antistatic agents, texture improvers, light resistance improvers, flame retardants, flame retardants, etc. In the water repellent treatment agent for fibers, the total amount of other components relative to the total of 100 mass% of components other than supercritical carbon dioxide may in one embodiment be 1 mass% or more, or 5 mass% or more, and in one embodiment may be 50 mass% or less.

　An organic solvent may be added to increase the solubility of the textile water repellent treatment agent in supercritical carbon dioxide. Examples of organic solvents include monohydric alcohols such as methanol, ethanol, normal propanol, isopropanol, normal butanol, isobutanol, secondary butanol, tertiary butanol, pentanol, 2-ethylhexanol, benzyl alcohol, and metaethoxybenzyl alcohol; polyhydric alcohols such as ethylene glycol, diethylene glycol, glycerin, triethylene glycol, and propylene glycol; glycol ethers such as propylene glycol monomethyl ether, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol butyl ether, butyl diglycol, and diisopropyl ether; tetrahydrofuran, tetrahydrofuran, and tetrahydrofuran; Ethers such as furan; esters such as ethyl acetate, n-butyl acetate, isobutyl acetate, sec-butyl acetate, methoxybutyl acetate, ethyl lactate, methyl lactate, and butyl lactate; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, diisobutyl ketone, methyl isopropyl ketone, and cyclohexanone; hydrocarbons such as toluene, xylene, normal pentane, normal hexane, isohexane, normal heptane, isoheptane, isooctane, normal nonane, cyclohexane, cyclohexene, ethylcyclohexane, methylcyclohexane, naphtha, mineral spirits, and paraffin; and nitrogen-containing compounds such as pyridine, N-methylpyrrolidone, and N-vinylpyrrolidone.

An antibacterial and antiviral agent that does not easily inhibit water repellency is preferably used. Examples of antibacterial agents include quaternary ammonium salts such as dimethyloctadecyl ammonium chloride, lauryl dimethylhydroxyethyl ammonium butyl phosphate, hexadecyl ethyl dimethyl ammonium ethyl sulfate, and didecyl dimethyl ammonium methyl sulfate; phosphoric acid esters such as alkyl group-containing phosphoric acid monoesters and alkyl group-containing phosphoric acid diesters; phosphoric acid ester salts such as alkyl group-containing phosphoric acid monoester salts and alkyl group-containing phosphoric acid diester salts; silver ions, copper ions, zinc ions, and other metal ions; selenium disulfide, zinc pyrithione, sodium pyrithione, 2-(4-thiazolyl)-benzimidazole, 10,10'-oxybisphenoxanodine, pyridine-2-thiol-oxide, salicylic acid, and oxazoline. Antibacterial and antiviral agents can be used alone or in combination of two or more.

It is advisable to use an anti-mold agent that does not easily impair water repellency. Examples of anti-mold agents include sodium hypochlorite, hydroxybenzoic acid esters, benzoates, phenylphenols, alcohols such as phenoxyethanol, benzalkonium chloride, triazole compounds, etc. Anti-mold agents can be used alone or in combination of two or more.

It is advisable to use dyes that do not easily impair the water-repellent performance. Examples of dyes include anthraquinone compounds, azo compounds, monochlorotriazine compounds, vinyl sulfone compounds, acid dyes such as Kayanol Milling Blue BW and Lanaset Blue 2R, metal-containing dyes such as Irgaran Blue 3GL and Isolan Navy Blue S-RL, etc. Dyes can be used alone or in combination of two or more.

It is best to use a pigment that is not likely to interfere with the water-repellent properties. Examples of pigments include inorganic pigments such as carbon black, titanium oxide, zinc oxide, lithopone, iron oxide, kaolinite, montmorillonite, talc, barium sulfate, calcium carbonate, silica, alumina, cadmium red, red iron oxide, molybdenum red, chrome vermilion, molybdate orange, chrome yellow, cadmium yellow, yellow iron oxide, titanium yellow, chromium oxide, viridian, cobalt green, titanium cobalt green, cobalt chrome green, ultramarine blue, Prussian blue, cobalt blue, cerulean blue, manganese violet, cobalt violet, and mica; and organic pigments such as azo compounds, azomethine compounds, polyazo compounds, phthalocyanine compounds, quinacridone compounds, anthraquinone compounds, indigo compounds, thioindigo compounds, quinophthalone compounds, benzimidazolone compounds, isoindoline compounds, and isoindolinone compounds. Pigments can be used alone or in combination of two or more.

It is advisable to use a deodorant that does not easily impair the water repellency. Examples of deodorants include hydroxy acids such as citric acid, malic acid, tartaric acid, and lactic acid; inorganic compounds such as silicon dioxide or a reaction product of silicon dioxide and zinc oxide; sugars such as cyclodextrin; and alcohols such as ethanol. Deodorants can be used alone or in combination of two or more.

Antistatic agents that do not easily impair water-repellent performance are preferably used. Examples of antistatic agents include anionic surfactants such as higher alcohol sulfates, sulfated oils, and sulfonates; cationic surfactants such as quaternary ammonium salts and imidazoline-type quaternary salts; nonionic surfactants such as polyethylene glycol types and polyhydric alcohol ester types; and amphoteric surfactants such as alanine types and betaine types. Examples of polymeric compound types include polyalkylamines. Antistatic agents can be used alone or in combination of two or more types.

It is preferable to use a texture improver that does not easily impair water repellency. Examples of texture improvers include amino-modified silicone, epoxy-modified silicone, organo-modified silicone, dimethyl silicone, aliphatic amide compounds, and aliphatic ester compounds. However, the above silicones are not included in the silicone resin containing M units of this embodiment. Texture improvers can be used alone or in combination of two or more.

It is preferable to use a light resistance improver that does not easily impair water repellency. Examples of light resistance improvers include benzotriazole derivatives, triazine derivatives, and hindered amine derivatives. Light resistance improvers can be used alone or in combination of two or more.

It is preferable to use a flame retardant that does not easily impair water repellency. Examples of flame retardants include phosphorus compounds such as triphenylphosphine compounds, phosphaphenanthrene compounds, halogen-containing phosphate esters, and aromatic phosphate esters; and bromine compounds. Flame retardants can be used alone or in combination of two or more.

It is advisable to use a flame retardant that does not easily impair water repellency. Examples of flame retardants include phosphorus compounds such as phosphoric acid ester amide compounds, phosphorus nitrogen compounds, and phosphorus carbamates; bromine compounds, etc. Flame retardants can be used alone or in combination of two or more.

<Water-repellent textile products>
One aspect of the present invention provides a water-repellent textile product treated with the water-repellent treatment agent for textiles. The water-repellent textile product treated with the water-repellent treatment agent for textiles includes or consists of a substrate and a silicone resin containing M units. The silicone resin containing M units uses supercritical carbon dioxide, which is a fluid, as a medium, and therefore can be absorbed into the substrate (i.e., introduced from the outside to the inside of the substrate) and/or adhere to the substrate surface.

The substrate includes fibers. The substrate is not particularly limited, but examples include substrates whose main material is a polymer compound. The polymer compound here may be either a synthetic polymer compound or a natural polymer compound. Specific examples of substrates include textile products, leather, etc.

There are no particular limitations on the fibers contained in the substrate, and examples include natural fibers such as cotton, linen, silk, and wool; semi-synthetic fibers such as rayon and acetate; synthetic fibers such as nylon, polyester, polyurethane, and polypropylene; composite fibers thereof; and blended fibers thereof. The substrate may be in the form of a textile product such as thread, cloth (nonwoven fabric, woven fabric, knitted fabric, etc.), or paper.

An example of a method for confirming the exhaustion of the silicone resin containing M units into the substrate and/or the adhesion to the substrate surface is a method in which a substrate is treated in a water repellent treatment agent for fibers, which is made of a silicone resin containing M units contained in supercritical carbon dioxide, to obtain a water repellent textile product, and then a cross-sectional slice of the water repellent textile product is prepared and analyzed using an electron microscope. For example, elemental mapping analysis using a scanning electron microscope (SEM-EDX) may be used to confirm whether silicon atoms are detected inside the cross section of a single fiber or on the fiber surface. When the substrate contains silicon, this may be confirmed or inferred from the distribution state of silicon atoms in elemental mapping analysis.
Other techniques include X-ray photoelectron spectroscopy (XPS) to confirm the bonding state of silicon atoms, or nuclear magnetic resonance (NMR) to confirm silicon atoms derived from silicone resins and polysiloxanes.
These approaches may be combined.

<Method of manufacturing water-repellent textile products>
One aspect of the present invention provides a method for producing a water-repellent textile product. The method includes treating a substrate with the water repellency treatment agent for fibers to obtain a water-repellent textile product. That is, in the method for producing a water-repellent textile product of this embodiment, the substrate is subjected to a water repellency treatment in supercritical carbon dioxide.
The procedure for producing the water-repellent textile product will now be described.

In this embodiment, in supercritical carbon dioxide, a silicone resin containing M units is absorbed into the substrate and/or adhered to the substrate surface. For example, the substrate and the water repellent treatment agent for fibers are allowed to coexist in a supercritical carbon dioxide treatment device. The supercritical carbon dioxide treatment device is a pressure resistant kettle, which may be made of, for example, thick stainless steel.

The supercritical carbon dioxide processing device has an openable door or lid, which is opened to place the substrate in the supercritical carbon dioxide processing device under atmospheric pressure. The inside of the supercritical carbon dioxide processing device is preferably provided with a mechanism for holding the substrate, such as a cylindrical tube. The supercritical carbon dioxide processing device is preferably equipped with a mechanism for stirring the fluid within the device. This can reduce unevenness in the absorption and/or adhesion of the silicone resin containing M units to the substrate.

The water repellent agent for textiles may be formed in a supercritical carbon dioxide treatment device. First, carbon dioxide is introduced into the supercritical carbon dioxide treatment device and a pressurizing operation is performed. For example, a valve on a carbon dioxide supply line that is fluidly connected to the supercritical carbon dioxide treatment device may be opened to introduce carbon dioxide into the supercritical carbon dioxide treatment device and pressurize the inside of the supercritical carbon dioxide treatment device. At this time, the carbon dioxide in the supercritical carbon dioxide treatment device may be made into a supercritical fluid by setting the temperature and pressure in the device to preset values. The critical points of carbon dioxide are a temperature of 31.1°C and a pressure of 7.4 MPa, and carbon dioxide becomes a supercritical fluid when these are exceeded. Note that it is preferable to degas the air in the supercritical carbon dioxide treatment device by reducing the pressure before introducing carbon dioxide into the supercritical carbon dioxide treatment device.

The silicone resin containing M units and any other components may be introduced into the supercritical carbon dioxide treatment device at any time before the carbon dioxide in the device becomes a supercritical fluid, or may be introduced into the device after it is filled with supercritical carbon dioxide. In the latter case, a preparation tank for dissolving and/or dispersing the silicone resin containing M units and any other components in supercritical carbon dioxide may be provided separately from the supercritical carbon dioxide treatment device. This allows the silicone resin containing M units and any other components to be dissolved and/or dispersed in supercritical carbon dioxide to produce a fluid as a water repellent treatment agent for fibers, and the fluid may be introduced into the supercritical carbon dioxide treatment device from the preparation tank through a pipe. In one embodiment, a pipe for injecting the water repellent treatment agent for fibers into the supercritical carbon dioxide treatment device and a pipe for discharging the water repellent treatment agent for fibers from the supercritical carbon dioxide treatment device may be installed between the supercritical carbon dioxide treatment device and the preparation tank, and a pump may be installed between the pipes and driven. In this case, by circulating the water repellent treatment agent for fibers inside the supercritical carbon dioxide treatment device, the silicone resin containing M units can be efficiently exhausted and/or adhered to the substrate. Alternatively, by attaching an agitator inside the supercritical carbon dioxide treatment device at a position that does not contact the mechanism (e.g., a cylindrical tube) that holds the substrate, and agitating the water repellent treatment agent for fibers inside the supercritical carbon dioxide treatment device, the silicone resin containing M units can be efficiently exhausted and/or adhered to the substrate.

When the water repellent treatment agent for fibers contains one or more other components in addition to the silicone resin containing M units and supercritical carbon dioxide, the other components may be introduced into the device in a form mixed with the silicone resin containing M units or separately from the silicone resin containing M units. For example, when an organic solvent is introduced, the organic solvent may be introduced from a location in the supercritical carbon dioxide treatment device that does not come into contact with the substrate and the silicone resin containing M units at any timing before the supercritical carbon dioxide becomes a supercritical fluid, or any other component other than the silicone resin containing M units and the organic solvent may be dissolved in the organic solvent and introduced into the supercritical carbon dioxide treatment device at a location that does not come into contact with the substrate.

The amount of silicone resin containing M units contained in the supercritical carbon dioxide is preferably 0.01% o.w.f. or more. If the amount of silicone resin containing M units is too small, sufficient water repellency may not be obtained. On the other hand, if the amount of silicone resin containing M units is too large, the silicone resin containing M units dissolved and/or dispersed in the supercritical carbon dioxide may become saturated, and the silicone resin may remain in the device, causing problems such as pot staining. From these points of view, the above amount is preferably 0.01% o.w.f. or more, or 0.1% o.w.f. or more, or 0.5% o.w.f. or more, or 0.7% o.w.f. or more, and preferably 20% o.w.f. or less, or 15% o.w.f. or less, or 10% o.w.f. or less. Note that, when the % o.w.f. represents the weight percentage of silicone resin containing M units when the weight of the substrate is taken as 100% by weight.

When treating a substrate in supercritical carbon dioxide, the pressure inside the supercritical carbon dioxide treatment device may be within a range in which the carbon dioxide inside the supercritical carbon dioxide treatment device is in a supercritical state, but may be adjusted appropriately depending on the type and amount of the silicone resin containing M units, substrate, etc. If the pressure is high, the energy required to generate supercritical carbon dioxide increases. On the other hand, the higher the pressure, the easier it is for the silicone resin containing M units to dissolve and/or disperse in supercritical carbon dioxide. From these viewpoints, the preferred pressure is 13 to 50 MPa, the more preferred pressure is 15 to 40 MPa, and the even more preferred pressure is 17 to 30 MPa.

When treating a substrate in supercritical carbon dioxide, the temperature inside the supercritical carbon dioxide treatment device may be within a range in which the carbon dioxide inside the supercritical carbon dioxide treatment device is in a supercritical state, but may be adjusted appropriately depending on the type and amount of the silicone resin containing M units, substrate, etc. If the temperature is high, the energy required to generate supercritical carbon dioxide increases, and the silicone resin containing M units becomes difficult to dissolve and/or disperse in supercritical carbon dioxide. On the other hand, if the temperature is too low, the diffusion movement of the water repellent treatment agent for fibers in supercritical carbon dioxide decreases, and the silicone resin containing M units becomes difficult to adhere to the substrate surface or to be absorbed into the substrate. From these viewpoints, the preferred temperature is 40°C to 130°C, more preferably 40°C to 110°C, and even more preferably 40°C to 100°C.

In one embodiment, the time for treating the substrate in supercritical carbon dioxide is 10 minutes or more. If the time is long, the energy required to generate supercritical carbon dioxide increases. On the other hand, if the time is short, the silicone resin containing M units may not adhere sufficiently to the substrate surface or may not be sufficiently absorbed into the substrate, resulting in uneven exhaustion and/or adhesion of the silicone resin containing M units. From these viewpoints, the preferred time is 20 to 240 minutes, the more preferred time is 20 to 210 minutes, and the even more preferred time is 20 to 180 minutes.

Once the treatment with the water repellent agent for textiles is complete, the discharge valve is opened and the fluid is discharged from inside the supercritical carbon dioxide treatment device. From the viewpoint of avoiding problems such as deterioration of the substrate, it is preferable that the discharge speed is as slow as possible. For example, if the substrate contains polyethylene terephthalate (PET), an excessively high discharge speed can easily cause a sudden drop in pressure, which can lead to the generation of PET oligomers, so it is desirable to slow down the discharge speed. After the fluid is discharged, the substrate to which the silicone resin containing M units has been exhausted and/or adhered is taken out as the desired water repellent textile product.

In addition, when recovering and reusing the carbon dioxide discharged from the supercritical carbon dioxide treatment device, it is preferable to introduce the fluid discharged from the supercritical carbon dioxide treatment device into a gas separation tank. In the gas separation tank, the carbon dioxide gas may be separated and recovered from the remaining components of the water repellent treatment agent for fibers (i.e., silicone resin containing M units, etc.) by reducing pressure or other methods. The recovered carbon dioxide may be introduced into the carbon dioxide supply line described above as a gas or liquefied.

The present invention will be explained in detail below with reference to examples, but the content of the present invention is not limited in any way by these examples.

The materials and substrates for manufacturing water-repellent textile products were prepared as follows:

[Silicone resin containing M units]
MQ resin (trimethylsilyl group-containing polysiloxane, manufactured by Dow Corning Toray Co., Ltd., product name: MQ-1600, hardness: 60, weight average molecular weight: 10,000, solid at 25°C)
[Dimethyl silicone] (non-resin silicone compound)
Dimethyl silicone (manufactured by Dow Corning Toray Co., Ltd., product name: SH-200, 100 cst (value at 25°C), weight average molecular weight: 12,000, liquid at 25°C)
[Methyl hydrogen silicone] (a non-resin silicone compound)
Methylhydrogen silicone (manufactured by Shin-Etsu Chemical Co., Ltd., product name: KF-99, functional group equivalent: 60 g/mol, weight average molecular weight: 1,000, liquid at 25° C.)

[Silicone resin not containing M units]
(DT resin)
The samples were prepared as follows.
In a 500 ml four-necked separable flask equipped with a thermometer and a stirrer, 88 g of hydrolysis condensate of tetramethoxysilane (oligomer with average tetramer), 110 g of octamethyltetracyclosiloxane, and 0.2 g of trifluoromethanesulfonic acid were added and stirred, and 0.2 g of water was further added. The resulting mixture was stirred at 80° C. for 4 hours and then neutralized by passing ammonia gas through it. The mixture was filtered, and the filtrate was stripped at 100° C. under reduced pressure to obtain the target compound. The weight average molecular weight was 2,000 according to the GPC measurement result.

(DQ Resin)
The samples were prepared as follows.
In a 500 ml four-necked separable flask equipped with a thermometer, a stirrer, and a dropping funnel, 147 g of methyltrimethoxysilane, 14 g of octamethyltetracyclosiloxane, 5 g of methanol, and 0.1 g of trifluoromethanesulfonic acid were added and stirred, and the temperature was raised to 60° C. 24 g of water was added dropwise to the mixture over 1 hour. The resulting mixture was stirred at 60° C. for 4 hours and then neutralized by introducing ammonia gas. The mixture was filtered, and the filtrate was concentrated at 115° C. to obtain a liquid residue. The weight average molecular weight was 6,500 according to the GPC measurement results.

[Hardness]
The hardness was measured according to JIS K 6249:200313. Hardness test using a type A durometer (manufactured by Major Co., Ltd., model number: GSD-719J).

[Weight average molecular weight]
The weight average molecular weight was measured by gel permeation chromatography (GPC) according to the following procedure.
20 mg of the measurement sample was dissolved in 5 ml of a THF/toluene mixed solution (250 ml/0.1 ml), and the solution was filtered with 5C filter paper to prepare a measurement sample. Next, the molecular weight was measured using a GPC device (Tosoh Technosystem Co., Ltd., model number: HLC-8320), a semi-micro SEC column (TSKgel Super Multipore Hz) as a column, and THF as a mobile phase.

[Base material]
Polyethylene terephthalate knitted piece (10.5 cm x 50 cm, 14 g)

(Production of water-repellent textile products)
Example 1
After wrapping the substrate around a cylindrical tube, the substrate was fixed to the cylindrical tube with silk thread and set in a 400 mL supercritical carbon dioxide treatment device. 0.14 g (1% owf) of silicone resin containing M units was wrapped in a medicine wrapping paper and set in the supercritical carbon dioxide treatment device so as not to come into contact with the substrate. After closing the lid of the supercritical carbon dioxide treatment device, the temperature inside the treatment device was heated to 40°C. Then, while cooling the carbon dioxide injection pump to 10°C or less, the carbon dioxide injection valve was opened, and while rotating the stirrer attached to the top of the device, carbon dioxide was injected until the pressure inside the tank reached 25 MPa. After carbon dioxide injection, the carbon dioxide injection valve was closed. 30 minutes after the injection of injected carbon dioxide, the carbon dioxide exhaust valve was opened, and after the pressure of the supercritical carbon dioxide treatment device reached 0 MPa, the treated cloth was taken out. By the above operations, a water-repellent textile product 1 was produced.

Example 2
Water-repellent textile product 2 was produced in the same manner as in Example 1, except that the temperature inside the treatment device in Example 1 was changed to 60°C.

Example 3
Water-repellent textile product 3 was produced in the same manner as in Example 1, except that the temperature inside the treatment device in Example 1 was changed to 80°C.

Example 4
Water-repellent textile product 4 was produced in the same manner as in Example 1, except that the temperature inside the treatment device in Example 1 was changed to 110°C.

(Example 5)
Water-repellent textile product 5 was produced in the same manner as in Example 3, except that the pressure inside the treatment device was changed to 15 MPa.

Example 6
Water-repellent textile product 6 was produced in the same manner as in Example 3, except that the pressure inside the treatment device was changed to 20 MPa.

(Example 7)
Water-repellent textile product 7 was produced in the same manner as in Example 3, except that the amount of silicone resin containing M units was changed to 0.070 g (0.5% owf).

(Example 8)
Water-repellent textile product 8 was produced in the same manner as in Example 3, except that the amount of silicone resin containing M units was changed to 0.105 g (0.75% owf).

(Comparative Example 1)
Water-repellent textile product 9 was produced in the same manner as in Example 3, except that the silicone resin containing M units was changed to dimethyl silicone.

(Comparative Example 2)
A water-repellent textile product 10 was produced in the same manner as in Example 3, except that the silicone resin containing M units was changed to methyl hydrogen silicone.

(Comparative Example 3)
Water-repellent textile product 11 was produced in the same manner as in Comparative Example 2, except that the temperature inside the treatment device was changed to 120°C.

(Comparative Example 4)
A water-repellent textile product 12 was produced in the same manner as in Example 3, except that the silicone resin containing M units was changed to DT resin.

(Comparative Example 5)
Water-repellent textile product 13 was produced in the same manner as in Example 3, except that the silicone resin containing M units was changed to DQ resin.

(Comparative Example 6)
A water-repellent textile product 14 was produced in the same manner as in Example 3, except that the pressure inside the treatment device was changed to 7 MPa and a non-supercritical state was established.

The drug adhesion rate and exhaustion rate in the examples and comparative examples were measured using the following methods.

<Measurement of drug adhesion rate>
The bone dry weight of the treated fabric sample was measured before and after the treatment, and calculated according to the following formula.
Drug adhesion rate (%) = 100 × (W2 - W1) / W0
W0: weight of silicone compound charged (g)
W1: Bone-dry weight (g) of treated fabric sample before treatment
W2: Bone-dry weight (g) of treated fabric sample after treatment
The treated fabric was dried in accordance with JIS L0105 (2020) 5.3.2, and the dry weight was measured. Specifically, the procedure was as follows.
The treated fabric sample was dried at 105° C. for 2 hours in a constant temperature blower dryer (model: DRM420DD, manufactured by Advantec Toyo Kaisha, Ltd.) to an absolute dry state, and then the absolute dry weight was measured.

<Measurement of exhaustion rate>
The bone dry weight of the treated fabric sample was measured before the treatment and after 30 washes, and the weight loss was calculated using the following formula: The washing was performed in accordance with JIS L 0217 (1995) Method 103.
Exhaustion rate (%) = 100 × (W3-W1)/W0
W0: weight of silicone compound charged (g)
W1: Bone-dry weight (g) of treated fabric sample before treatment
W3: Bone-dry weight (g) of treated fabric sample after 30 washes

The water repellency of the water repellent textile product obtained above was measured before washing (HL-0) and after 30 washes (HL-30) using the following method. The results are shown in Table 1.

(Water repellency evaluation of water repellent textile products)
The test was conducted according to the spray method of JIS L 1092 (2009) with shower water temperature at 20°C (HL-0). The results were visually evaluated using the following grades. If the characteristics were slightly better, a "+" was added to the grade, and if the characteristics were between grades 4 and 5, the grade was rated as "4-5." A water repellency of 3 or higher on HL-0 was considered to be a pass.
Water repellency: Condition 5: No adhesion or wetting on the surface 4: Slight adhesion or wetting on the surface 3: Partial wetting on the surface 2: Wetting on the surface 1: Wetting on the entire surface 0: Complete wetting on both the front and back surfaces

(Evaluation of Durability of Water-Repellent Textile Products)
The water-repellent textile product was washed 30 times (HL-30) according to the 103 method of JIS L 0217 (1995), and the water repellency after air drying was evaluated in the same manner as the water repellency evaluation method described above. A water repellency of 3 or more after HL-30 was considered to be acceptable.

(Evaluation of Pot Fouling)
After the processing was completed and the water-repellent textile product and the chemicals were removed from the device, another substrate was wrapped around a cylindrical tube, and then the substrate was fixed to the cylindrical tube with silk thread and set in a 400 mL supercritical carbon dioxide treatment device. After closing the lid of the supercritical carbon dioxide treatment device, the temperature inside the treatment device was heated to 40°C. Then, while cooling the carbon dioxide injection pump to 10°C or less, the carbon dioxide injection valve was opened, and while rotating the stirrer attached to the top of the device, carbon dioxide was injected until the pressure inside the tank reached 25 MPa. After carbon dioxide injection, the carbon dioxide injection valve was closed. 30 minutes after carbon dioxide injection, the carbon dioxide discharge valve was opened, and after the pressure of the supercritical carbon dioxide treatment device reached 0 MPa, the treated cloth was taken out. The above procedure obtained a throw-dyed treated cloth. Five arbitrary points of the throw-dyed treated cloth were subjected to X-ray fluorescence analysis (XRF), and the average Si amount (mass basis) of the five measurement points was calculated. Evaluation was performed according to the following criteria, and a rating of 3 or more was considered to be acceptable.
5: Si content is less than 100 ppm 4: Si content is 100 ppm or more and less than 300 ppm 3: Si content is 300 ppm or more and less than 1,000 ppm 2: Si content is 1,000 ppm or more and less than 5,000 ppm 1: Si content is 5,000 ppm or more

It was confirmed that the water-repellent textile products treated with the textile water-repellent treatment agents of Examples 1 to 8 had sufficient water repellency and excellent washing durability even after HL-30.

The present invention can provide a water-repellent treatment agent for textiles that enables water-repellent processing to be performed in supercritical carbon dioxide, which reduces pot staining and achieves sufficient water-repellent performance and washing durability (hence durable water repellency), despite the use of a silicone-based compound; a water-repellent textile product treated with the water-repellent treatment agent for textiles; and a method for producing the water-repellent textile product.

Claims (3)

A water repellent treatment agent for fibers, comprising a silicone resin containing M units contained in supercritical carbon dioxide. A water-repellent textile product treated with the water-repellent textile treatment agent according to claim 1. A method for producing a water-repellent textile product, comprising the steps of:
A method for producing a water-repellent textile product comprising treating a substrate with the water-repellent treating agent for textiles according to claim 1,
The method for producing a water-repellent textile product comprises carrying out the treatment under conditions in which the temperature of the supercritical carbon dioxide is in the range of 40°C to 130°C.