JP4560352B2 - Natural leather water repellent treatment method - Google Patents

Description

The present invention relates to an impregnation treatment method in which a substrate is impregnated with an impregnation substance in supercritical carbon dioxide. In particular, the present invention relates to a method for impregnating a natural leather with a water repellent, such as a water repellent having a molecular weight of a certain level or more , which is impregnated into a base material in supercritical carbon dioxide containing a specific cosolvent.

  Various treatments can be applied to the substrate by impregnating the substrate with various impregnating substances. As such an impregnation treatment method, a method of bringing a substrate into contact with a solution or dispersion containing an impregnation substance is often employed. For example, when a water repellent treatment is performed on a base material, a method of introducing the base material into a water-based emulsion containing a water repellent, a parkren solution, or a petroleum-based solution is widely adopted. However, in these methods using water or an organic solvent as a medium, for example, when natural leather is used as a base material, there is a problem that the texture of the base material is damaged or shrunk. Further, in this case, water and organic solvent are likely to remain on the base material, and it takes a long time for the drying treatment to remove them. In particular, since natural leather has a structure in which fine fibers are intertwined in a complicated manner, the above method using water or an organic solvent as a medium makes it difficult to impregnate a base material with a water repellent. It was not easy to obtain a water repellent effect.

  Patent Document 1 describes a method for producing a leather material in which a high-pressure fluid is used as a medium to infiltrate a leather tissue and an active ingredient to be imparted into fibers. According to this method, it is said that by using a high-pressure fluid such as supercritical carbon dioxide as a medium, a leather product that does not impair the natural characteristics of natural leather such as stretchability and water absorption can be provided. In addition, compared to the method of simply attaching components to the surface of the leather material, the active ingredient penetrates deep into the tissue and fibers of the leather material. It is said that it is possible to provide a leather product in which the imparting effect is maintained for a long time without the components being scattered. Here, as an active ingredient used, a fragrance ingredient is typical. Further, although there is a description that an organic solvent such as a lower alcohol is used as an auxiliary solvent in order to extract impurities such as lipids contained in leather, there is no description that a co-solvent is used when impregnating the active ingredient.

  In Patent Document 2, a water repellent having a molecular weight of 1000 or more and a fluorine-based compound and / or a silicone-based compound treats a fiber structure in a fiber processing agent contained in supercritical carbon dioxide. A method for manufacturing a fiber structure is disclosed. According to this production method, it is said that the compound can be introduced into the inside of the fiber, and the durability of water repellency and the effect of deep color can be greatly improved. Here, examples of the fiber structure to be treated include woven fabrics, knitted fabrics, nonwoven fabrics, and the like made of natural fibers, synthetic fibers, and the like, and among them, fiber structures containing polyester fibers or nylon fibers are important. Has been. In Patent Document 2, it is said that a fluorine-based compound and / or a silicone-based compound is contained in a supercritical fluid by being dissolved, dispersed, emulsified, etc., but there is no description about a co-solvent.

  In Patent Document 3, a water repellent such as vinylidene fluoride is dissolved in high-pressure carbon dioxide by utilizing a specific coexistence effect in which a mixture containing high-pressure carbon dioxide and a polar solvent exhibits extremely large dissolving power only at the time of mixing. A fiber processing method for functionally processing fibers is described. According to this method, by selectively adding a polar solvent, the affinity between fibers and carbon dioxide can be controlled, and the water-repellent processing of fibers and blended fabrics, which has been considered difficult in the past, can be performed. ing. At this time, the solvent used together with the high-pressure carbon dioxide is a polar solvent such as methanol or acetone.

JP 2004-27175 A (claims, effects of the invention, [0071]) JP 2000-220074 (Claims, Effects of the Invention, [0019] to [0022]) JP 2002-4169 A (claims, effects of the invention, [0013], [0015])

The present invention has been made to solve the above problems, without impairing the texture of the substrate, water-repellent natural leather that can be impregnated with the impregnation material having a certain level of molecular weight to the inside of the substrate It is an object of the present invention to provide an impregnation treatment method for an agent .

The above-mentioned problem is an impregnation treatment method for impregnating a substrate with an impregnation substance in supercritical carbon dioxide, the impregnation substance having a peak molecular weight of 1000 or more in GPC measurement of the impregnation substance, and 100 ml of water at 20 ° C. It is solved by providing an impregnation treatment method characterized in that the supercritical carbon dioxide contains a co-solvent having a solubility with respect to 100 g / 100 ml or less. In particular, when impregnating a substrate made of natural leather with at least one impregnating material selected from the group consisting of a water repellent, a waterproofing agent and an oil repellent in supercritical carbon dioxide, the impregnating material is One of normal paraffin, mineral spirit, and methyl isobutyl ketone, which is a fluorine-based compound or a silicone-based compound having a peak molecular weight of 1000 or more in GPC measurement and a cosolvent having a solubility in 100 ml of water at 20 ° C. of 2 g / 100 ml or less, or A mixture of two or more kinds is 0.01 to 10% in the supercritical carbon dioxide (however, the content of the cosolvent is a value obtained by dividing the volume of the added cosolvent under normal pressure by the volume of the supercritical fluid) In a bath in which a solution in which the impregnating substance is dissolved in the co-solvent in advance is supplied into the impregnation treatment tank so as to be dissolved. The impregnated material is solved by impregnating into the inside of the natural leather.

In this case, it is preferable that the content of the co-solvent is from 0.01 to 10%, as described above. However, the content ratio of the cosolvent is a value (%) obtained by multiplying the value obtained by dividing the volume of the added cosolvent under normal pressure by the volume of the supercritical fluid by 100.

  It is also preferred that the impregnating material is a fluorine compound or a silicone compound. It is also preferable that the impregnating material is at least one selected from the group consisting of a water repellent, a waterproofing agent and an oil repellent. It is also preferable that the impregnating substance is soluble in the co-solvent. In this case, it is preferable to supply a solution obtained by dissolving the impregnating substance in the co-solvent into the impregnation treatment tank.

  It is preferable that the substrate is a hydrophilic substrate. It is also preferred that the substrate is natural leather. It is also preferable that the substrate is a sewn product.

  According to the impregnation treatment method of the present invention, an impregnating substance having a peak molecular weight of 1000 or more in GPC measurement can be impregnated to the inside of the substrate without impairing the texture of the substrate. In particular, it is suitable for water repellent processing of natural leather having a specific tissue structure in which fine fibers are intertwined in a complicated manner.

  The impregnation treatment method of the present invention is a method of impregnating a base material with an impregnation substance in supercritical carbon dioxide. Although there are many compounds that form a supercritical fluid, carbon dioxide is used in the present invention from the viewpoint of safety and cost. The critical point of carbon dioxide is a temperature of 31.3 ° C. and a pressure of 7.4 MPa, and it is relatively easy to make a supercritical fluid exceeding this temperature.

  The impregnating substance used in the present invention is a substance that can be impregnated into the substrate, and various substances can be used depending on the purpose. The impregnation here refers to, for example, when the base material is a structure made of fibers, not only the state in which the impregnating substance has penetrated into each single fiber constituting the base material, but also the inside of the structure. It also includes the state of adhering to the surface of the single fiber.

  The impregnated material has a peak molecular weight of 1000 or more in GPC measurement. When the impregnated material is a low molecular weight compound, it easily evaporates or migrates to the surface when used for a long time, so that it is difficult to hold it on the substrate for a long time. Therefore, in order to maintain the effect of the impregnation treatment for a long time, it is preferable to impregnate the base material with an impregnating substance having a molecular weight of a certain level or more. When the molecular weight is above a certain level, the impregnating substance is firmly fixed to the base material, so that the effect of the impregnation treatment can be exhibited stably without shifting in the base material. Usually, it is difficult to impregnate an impregnating substance having a molecular weight of a certain level or more into the inside of the base material only by immersing the base material in a treatment agent using water or an organic solvent as a medium. On the other hand, supercritical carbon dioxide is a hydrophobic medium and can dissolve low molecular weight compounds, particularly hydrophobic low molecular weight compounds, relatively easily. However, high molecular weight compounds can be dissolved or dispersed. Usually considered difficult. However, by impregnating a specific co-solvent in supercritical carbon dioxide, even an impregnated substance having a molecular weight of a certain level or more can be impregnated into the base material. is there. In particular, the above impregnating material can be impregnated even in the details of the structure of a base material having a structure of intricately entangled fine fibers.

  Here, the peak molecular weight in GPC measurement is a molecular weight in terms of polystyrene calculated from the elution time at the peak top of a GPC curve (elution curve) obtained by gel permeation chromatography (GPC). The impregnated material having two or more peak molecular weights may have a peak molecular weight at least 1000 or more at the position where the elution time is shortest. A typical solvent used in the GPC measurement is chloroform. The peak molecular weight is preferably 2000 or more, more preferably 3000 or more. The upper limit of the peak molecular weight is not particularly limited, but is preferably 1 million or less, more preferably 500,000 or less, and still more preferably 300,000, from the viewpoint of easy impregnation into the substrate and solubility in supercritical carbon dioxide. It is as follows.

  Further, the impregnated material having a peak molecular weight of 1000 or more in GPC measurement is often a polymer. A polymer is a compound obtained by polymerizing a monomer by various polymerization methods. There is no restriction | limiting in particular in a polymerization method, The monomer used for a polymer can be suitably selected according to the objective of an impregnation process. Further, as the polymer, not only a linear polymer but also a non-linear polymer such as a graft polymer, a comb polymer, a star polymer, a dendrimer, or a ladder polymer can be used.

  Among the impregnated materials, it is preferable to use a hydrophobic compound in the present invention. As described above, supercritical carbon dioxide is a hydrophobic medium, and hydrophobic compounds can be dissolved or dispersed in supercritical carbon dioxide relatively easily. Examples of the hydrophobic compound having a peak molecular weight of 1000 or more in GPC measurement include hydrocarbon compounds such as wax, paraffin, and polyolefin; polyesters; acrylic resins; fluorine compounds; silicone compounds.

  As the impregnating substance having a peak molecular weight of 1000 or more in GPC measurement, a fluorine compound or a silicone compound is preferably used. It is known that these compounds can be dissolved or dispersed relatively easily in supercritical carbon dioxide even when they have a molecular weight above a certain level. The substrate can be sufficiently impregnated with the impregnation material. Here, the fluorine compound refers to an organic compound containing a fluorine atom in the chemical structure, and examples thereof include perfluoroalkyl group-containing polymers, fluoroolefin polymers, perfluoropolyethers, fluorine elastomers, and the like. However, it is not limited to these. Examples of the perfluoroalkyl group-containing polymer include homopolymers of monomers such as vinyl ethers, vinyl esters and (meth) acrylates containing perfluoroalkyl groups, copolymers of the monomers, and other monomers and other polymers. Examples thereof include a copolymer with a monomer. Examples of the fluoroolefin polymer include a homopolymer of fluoroolefin, a copolymer of fluoroolefins, and a copolymer of fluoroolefin and other monomers. Examples include tetrafluoroethylene resin (PTFE), tetrafluoroethylene-ethylene copolymer (ETFE), tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), and polyvinylidene fluoride (PVDF). The Among them, a perfluoroalkyl group-containing polymer and a fluoroolefin polymer are more preferably used because of their solubility in supercritical carbon dioxide and the ease of impregnation into the substrate. Further, the silicone compound means a compound having a siloxane bond in the chemical structure, for example, unmodified silicone such as polydimethylsiloxane, polymethylphenylsiloxane, polymethylhydrogensiloxane, amino-modified, epoxy-modified, carboxyl-modified, alkyl / Various modified silicones such as aralkyl modification, hydroxyl group modification, polyether modification, fluorine modification, silicone rubber, silicone-based thermoplastic elastomer, and the like can be mentioned, but the invention is not particularly limited thereto.

  The purpose of the impregnating material is not particularly limited, but antibacterial agents, insecticides, fungicides, deodorants, deodorants, medicinal substances, softeners, hardeners, water repellents, oil repellents, wrinkle preventives, shrinking agents , Anti-pilling agent, waterproofing agent, antiperspirant, fluorescent brightening agent, darkening agent, antifouling agent, antistatic agent, fireproofing agent, flameproofing agent, flame retardant, flameproofing agent, antioxidant, anti-aging agent, Examples include ultraviolet absorbers, light resistance stabilizers, shape memory processing agents, electromagnetic wave shielding processing agents, polishing agents, matting agents, sewability improvers, smoothing agents, anti-slip agents, and the like. Among these, it is preferable to use at least one selected from the group consisting of a water repellent, a waterproof agent and an oil repellent. Usually, a water repellent, a waterproofing agent and an oil repellent are often dispersed or dissolved in a solvent and the substrate is immersed therein or applied to the surface of the substrate. However, since it is difficult to impregnate the impregnating material to the inside, the effect inside the base material is insufficient and there is a problem that water or oil is absorbed and held inside the base material. In order to maintain the water repellency, water repellency or oil repellency, it is required that these impregnating substances do not volatilize easily and do not easily elute into water or oil. It is preferable that it is a compound of these. Some water repellents need to be heat-treated after the impregnation treatment in order to exhibit a water repellent effect. However, when a heat-sensitive substrate such as natural leather is used as the substrate, an impregnating substance that has an effect as a water repellent, waterproofing agent and oil repellent without performing a heat treatment after the impregnation treatment is performed. Is preferably used. It is also possible to use antibacterial agents, deodorants and the like together with these impregnating substances.

  Examples of water repellents, waterproofing agents, and oil repellents include fluorine, silicone, paraffin, ethylene urea, zirconium, methylolamide, and wax. Commercially available water repellents include “Unidyne TG-656” (manufactured by Daikin Industries, Ltd.), “Modiper F3035”, “Modiper F2020”, “Modiper F600”, “Modiper F220”, “Modiper F200” (and above) Fluoro-based water repellents such as “Fluorosurf FS-7000” series, “Fluorosurf FS-2010” series, “Fluorosurf FG-4010” series (above, manufactured by Fluoro Technology Co., Ltd.), “TSF451” ”,“ TSF484 ”,“ XS66-B1101 ”,“ TSW-8251 ”(manufactured by GE Toshiba Silicon Corporation),“ Modiper FS700 ”,“ Modiper FS710 ”,“ Modiper FS720 ”,“ Modiper FS730 ”,“ Modiper ” FS770 "(above, Silicone-based water repellent of the present Yushi Co., Ltd.) and the like. Some of the water repellents have an effect as an oil repellent.

  The addition amount of the impregnation substance is preferably 0.01 g / L or more as the addition amount of the impregnation substance per unit volume of the impregnation treatment tank. If the amount is less than this, the effect of impregnating the substrate with the impregnating substance may not appear. More preferably, it is 0.1 g / L or more. Moreover, it is preferable that the addition amount is 50 g / L or less. When added in excess of 50 g / L, the texture of the substrate may be deteriorated. More preferably, it is 10 g / L or less.

  In the impregnation method of the present invention, supercritical carbon dioxide needs to contain a co-solvent having a solubility in 100 ml of water at 20 ° C. of 100 g / 100 ml or less. As described above, supercritical carbon dioxide may be able to dissolve or disperse impregnating substances having a certain degree of molecular weight without using a co-solvent. However, by containing the specific co-solvent, GPC measurement is possible. It is possible to impregnate the base material with a contained material having a peak molecular weight of 1000 or more.

  The cosolvent having a solubility in 100 ml of water at 20 ° C. of 100 g / 100 ml or less is not particularly limited as long as the solubility is within the above range. Examples thereof include hydrocarbons, ketones, ethers, alcohols, esters, chlorinated solvents, and the like. Examples of hydrocarbons include linear aliphatic hydrocarbons such as n-pentane, n-hexane and n-decane, alicyclic hydrocarbons such as branched aliphatic hydrocarbons and cyclohexane, and aromatics such as toluene and xylene. Examples are hydrocarbons and petroleum solvents. All of these hydrocarbons are hardly soluble in water at 20 ° C., and their solubility is less than 1 g / 100 ml. Examples of the ketone include methyl ethyl ketone (29), methyl isobutyl ketone (1.9), methyl isopropyl ketone (0.6) and the like. Examples of ethers include dimethyl ether (2.4) and diethyl ether (6.9). As alcohol, carbon number of main chains, such as 2-butanol (12.5), 1-butanol (7.7), 1-pentanol (2.7), 1-hexanol (0.59), is 4 or more. Aliphatic alcohols, aromatic alcohols such as benzyl alcohol (4), alicyclic alcohols such as cyclohexanol (4), heterocyclic alcohols, and the like. Examples of the ester include methyl acetate (24.4) and n-butyl acetate (0.7). Moreover, tetrachloroethylene (0.015) etc. are mentioned as a chlorinated solvent. The numerical value described in parentheses in the above examples is the solubility (g / 100 ml) in 100 ml of water at 20 ° C.

  The upper limit of the solubility in 100 ml of water at 20 ° C. is preferably 50 g / 100 ml or less, more preferably 20 g / 100 ml or less, still more preferably 5 g / 100 ml or less, particularly preferably 2 g / 100 ml or less.

  When the boiling point of the co-solvent is too low, the co-solvent is likely to be mixed into the recovered carbon dioxide gas. Therefore, considering that the co-solvent is recovered and reused, the boiling point is preferably high to some extent. The boiling point is preferably 40 ° C. or higher, more preferably 60 ° C. or higher, and even more preferably 80 ° C. or higher. Moreover, it is preferable that a boiling point is not too high from a viewpoint of the difficulty of remaining on a base material, and the ease of collection | recovery, It is 300 degrees C or less suitably, More preferably, it is 250 degrees C or less. Furthermore, hydrocarbons are optimal when considering worker safety and co-solvent costs. However, since aromatic hydrocarbons may generate a characteristic odor when they remain on the base material, it is desirable to use aliphatic hydrocarbons or alicyclic hydrocarbons as the main component. In consideration of environmental aspects, the co-solvent is preferably not a chlorinated solvent. These cosolvents may be used alone or in combination of two or more.

The content of the co-solvent added to the supercritical carbon dioxide is preferably 0.01 to 10%. When the content is less than 0.01%, the effect of adding the co-solvent is reduced, and the impregnated material may not be sufficiently infiltrated into the substrate. More preferably, it is 0.1% or more, further preferably 0.2% or more, and particularly preferably 0.5% or more. On the other hand, when the content of the co-solvent exceeds 10%, the co-solvent tends to remain on the substrate after the impregnation operation, and a post-treatment for removing the co-solvent may be separately required, which is not always preferable. Absent. More preferably, it is 7% or less, and further preferably 5% or less. "%" Here is a ratio of the volume of the co-solvent put into the container filled with the supercritical fluid under normal pressure to the volume of the supercritical fluid multiplied by 100,
[(Volume of added co-solvent) / (Volume of supercritical fluid)] × 100
It is shown by. Usually, the volume of the supercritical fluid substantially corresponds to the volume of the container.

  It is preferred that the impregnating material is soluble in the co-solvent. By being soluble in the co-solvent, the impregnating substance is easily dissolved or dispersed in the supercritical carbon dioxide, and the impregnating substance is easily impregnated into the base material. In this case, it is preferable that the impregnating substance is dissolved in a co-solvent and then supplied into the impregnation treatment tank. By feeding into the supercritical carbon dioxide in solution, it becomes easier to dissolve or uniformly disperse the impregnating material in the supercritical carbon dioxide, thereby better impregnating the substrate with the impregnating material. Can do. Moreover, by supplying in the state of a solution, workability | operativity of injection | throwing-in operation becomes favorable.

The base material impregnated by the impregnation treatment method of the present invention is not particularly limited, and examples thereof include a base material mainly composed of a polymer compound. The polymer compound referred to here may be either a synthetic polymer compound or a natural polymer compound. Specific examples of the substrate include fiber products, leather, wood, films, plastic molded products, and the like. More preferably, textile products, natural leather, and wood are used.

  Here, as a textile product, a woven fabric, a knitted fabric, a nonwoven fabric, etc. are illustrated. Moreover, the material which comprises a textile product is not specifically limited, Cotton, hemp, silk, wool, rayon, acetate, triacetate, nylon (6, 66), polyester, acrylic, polyethylene, polypropylene, aramid (meta type and para type) ), Polyurethane, vinylon, polyvinyl chloride, polyvinylidene chloride, and the like.

  By performing the impregnation treatment according to the method of the present invention, it is possible to impregnate the inside of an impregnating substance having a molecular weight of a certain level or more, even for a hydrophilic base material, which is usually difficult to penetrate into the inside. It becomes. In general, a hydrophilic substrate is highly water-absorbing and hygroscopic, and thus there is a great need to impart water repellency to the substrate. Therefore, a hydrophilic substrate is preferably used. Among them, it is preferable to impregnate natural fibers and natural leather. Examples of natural fibers include plant fibers such as cotton and hemp, or animal fibers such as silk and wool. Natural leather is a hydrophilic substrate having a structure in which protein fibers are intertwined in a complicated manner.

Further, a thick base material is often difficult to impregnate the base material with the impregnating substance in the conventional method, and therefore, the benefit of employing the impregnation treatment method of the present invention is great. An example of a thick substrate is a thick fabric. Examples of the fabric used here include woven fabric, knitted fabric, and non-woven fabric. In addition, natural leather, which can be said to be a natural non-woven fabric, is often a thick material and is a suitable base material. The basis weight of the substrate is preferably 50 g / m ² or more, more preferably 100 g / m ² or more, and further preferably 200 g / m ² or more. The basis weight is usually 5000 g / m ² or less.

  Since natural leather has a unique tissue structure in which fine protein fibers are intertwined in a complex manner, it is difficult to impregnate the tissue with the impregnating substance. Further, when the impregnation treatment is carried out using water or a solvent as a medium, it is often preferable as a substrate used in the impregnation treatment method of the present invention because it is often deformed or the texture is impaired. For example, when natural leather is subjected to water repellent treatment, it is preferable that water can hardly enter even from the cut ends because the water repellent can be impregnated into the tissue. The natural leather to be used is not particularly limited, and examples thereof include cow leather, pig leather, sheep leather, and deer leather. Further, fur is also preferably used as natural leather, and examples include mink, chinchilla, fox, and cocoon. Since artificial leather has a three-dimensional structure similar to natural leather, it is difficult to impregnate the artificial leather, and it is preferably used in the same manner as natural leather.

  As a base material used in the impregnation treatment method of the present invention, a sewn product is also preferably used. The sewn product refers to a product obtained by sewing a plurality of fabrics or leathers using yarn. When impregnated with water or a solvent as a medium, the sewn product tends to lose shape due to the difference in shrinkage between the yarn and the fabric or leather, and is impregnated in supercritical carbon dioxide. Is preferred. For example, in the case where a sewing product made of natural leather is impregnated with a water repellent using water as a medium, the natural leather may be removed during the impregnation process in water or during the drying process by heating to evaporate water. The impregnation method of the present invention is preferably used because it easily shrinks and easily loses its shape.

  At this time, in the case of a product in which different types of fabrics or leathers are stitched, when the impregnation treatment is performed using water as a medium, the shrinkage rate after the treatment is different for each fabric or leather, and the shape is lost. Since it is easy, the impregnation method of this invention is used preferably. For example, it is also preferable to use a product in which leather and fabric are stitched together as a base material.

  As these sewn products, various products can be used, but clothing is typical. Impregnation of various clothing such as shirts, blouses, jackets, coats, pants, skirts, suits, dresses, sweaters, T-shirts, trainers, ties, underwear (inners), socks, stockings, gloves, hats, etc. it can. In addition to these, a sewing product using natural leather has the greatest benefit of employing the impregnation method of the present invention. Sewing products using natural leather include jumpers, pants, gloves, belts, bags, shoes, hats, watch bands, etc., and it is optimal to impregnate these.

  Hereinafter, the impregnation treatment operation will be described. In the present invention, the base material is impregnated with the impregnation substance in supercritical carbon dioxide in the impregnation treatment tank. The impregnation treatment tank is composed of a pressure vessel and usually requires a pressure resistance of 10 MPa or more, preferably 15 MPa or more, more preferably 20 MPa or more. For example, a thick stainless steel impregnation tank is used.

  The impregnation treatment tank usually has a door or lid that can be opened and closed. The door or lid is opened, and the base material is put into the impregnation treatment tank in the atmosphere. It is also preferable that a rotating basket is provided inside the impregnation treatment tank. By introducing the substrate to be treated into the impregnation treatment tank and impregnating it while rotating, a uniform impregnation operation without unevenness can be performed. Moreover, since the base material does not directly touch the wall surface of the impregnation treatment tank, there is little damage to the base material, and the finished product is clean because fuzz etc. comes out of the rotating basket. In particular, it is suitable for processing a base material that easily changes its texture or loses its shape, such as natural leather or a sewing product. At this time, it is more preferable to attach a plurality of inner baskets, particularly a cylindrical inner basket, to the rotating frame, and to put the base material into the inner basket from the viewpoint of preventing the deformation of the mold.

  Carbon dioxide is introduced into the impregnation tank and pressurized. For example, the valve is opened, carbon dioxide is introduced into the impregnation treatment tank and pressurized, and the impregnation treatment is started by filling the tank with supercritical carbon dioxide. The critical point of carbon dioxide is a temperature of 31.3 ° C. and a pressure of 7.4 MPa. At this time, it is preferable to degas the air in the impregnation tank in advance before introducing carbon dioxide.

  The impregnating substance may be introduced into the impregnation treatment tank in advance, or may be introduced later into the impregnation treatment tank filled with supercritical carbon dioxide. Separately, a tank for dissolving the impregnating substance in supercritical carbon dioxide may be provided, and then introduced into the impregnation processing tank through a pipe. Further, the cosolvent can be introduced from the cosolvent tank into the impregnation treatment tank through a cosolvent supply pump and a valve. Among them, it is preferable to supply a solution in which the impregnating substance is dissolved in the cosolvent in advance into the impregnation treatment tank. For example, the solution can be supplied in advance by introducing it into an impregnation tank or by introducing the solution from a cosolvent tank into the impregnation tank.

  The impregnation treatment condition may be appropriately adjusted depending on the impregnation substance, the base material and the like, although the inside of the impregnation treatment tank may be in a supercritical state. A suitable pressure is 7 to 35 MPa. When it is less than 7 MPa, impregnation is often difficult, and more preferably 10 MPa or more. On the other hand, if it exceeds 35 MPa, the apparatus becomes large and the energy required for the impregnation treatment also increases, more preferably 30 MPa or less, and even more preferably 25 MPa or less.

  A suitable temperature for impregnation in supercritical carbon dioxide is 30 to 250 ° C. When the temperature is lower than 30 ° C., the impregnation treatment is not smooth and the operation time may be long. On the other hand, if the temperature exceeds 250 ° C., the base material and the impregnated material may be deteriorated, and the required energy also increases. More preferably, it is 150 ° C. or lower. Further, when impregnating with an impregnating substance that is particularly vulnerable to heating, or when impregnating a substrate that is particularly susceptible to heating, it may be preferable to set the temperature to 100 ° C. or lower. For example, when natural leather is used as the substrate, it is preferably 70 ° C. or lower, more preferably 50 ° C. or lower, and further preferably 40 ° C. or lower.

  The time required for the impregnation treatment is usually 5 to 240 minutes. If it exceeds 240 minutes, the working efficiency may decrease, and the impregnated material may deteriorate depending on the processing temperature. More preferably, it is 180 minutes or less. On the other hand, in a time of less than 5 minutes, there are many cases where the impregnation is not sufficient, and impregnation unevenness is likely to occur. More preferably, it is 10 minutes or more, More preferably, it is 20 minutes or more. When natural leather is used as a base material, since it has a structure in which fine fibers are intertwined in a complicated manner, it is often better to perform a relatively long impregnation treatment, and the impregnation treatment time is preferably 30. Minutes or more, more preferably 60 minutes or more.

  When the impregnation treatment is completed, the pressure reducing valve is opened to discharge the fluid after the impregnation treatment from the impregnation treatment tank. At this time, it is preferable that the temperature is once lowered to a non-supercritical state, and then the pressure is lowered by discharging carbon dioxide. As a result, the solubility of the impregnating substance in the fluid is reduced, and it is easily distributed to the base material side, so that it can be impregnated more effectively. When carbon dioxide is recovered and reused, it is preferably introduced into the gas separation tank. In the gas separation tank, the carbon dioxide gas is separated from the impregnated material and the cosolvent. The gas separation device need not be in the form of a tank, but is generally preferably in the form of a tank. The component to be separated is an impregnating substance that is a liquid component or a solid component, a cosolvent, or the like. It is preferable to recover and reuse the liquid removed from the carbon dioxide gas in the gas separation tank. The inside of the gas separation tank is usually set to a temperature of about −10 to 150 ° C. and a pressure of about 0.1 to 5 MPa. Here, the pressure of 0.1 MPa means that the pressure is the same as the atmospheric pressure, and the differential pressure when compared with the surrounding environment is zero. At this pressure, carbon dioxide exists as a gas and is separated from solid and liquid components.

  The carbon dioxide gas derived from the gas separation tank is preferably stored in a tank after being compressed by a compressor. At this time, it is preferable to store as liquefied carbon dioxide. Although the temperature and pressure of the stored liquefied carbon dioxide are not particularly limited, the temperature is usually about 0 to 40 ° C. and the pressure is 3 to 10 MPa.

  The carbon dioxide recovered in this way is reused and the impregnation treatment is performed again. Taking a water repellent treatment operation as an example, when a substrate is impregnated with a water repellent agent in supercritical carbon dioxide, compared with the case of treating with water or a solvent as a medium, the drainage is not discharged. Originally an environmentally friendly process. In addition to this, it is also excellent in terms of energy in that it does not require energy for drying the substrate after the water repellent treatment. Moreover, since the carbon dioxide of the medium can be recovered and reused in this way, it is a very significant process from the viewpoint of environmental protection.

  Here, when the base material is natural leather, it is desirable to circulate supercritical carbon dioxide for a predetermined time after the base material is put into the impregnation treatment tank and before the impregnation material is impregnated. When supercritical carbon dioxide penetrates into the base material, impurities such as fats and oils and moisture remaining in the gaps between fine fibers of natural leather can be extracted and infiltrated into the impregnated substance. Therefore, it is preferable that a sufficient space can be secured and the leather is sufficiently impregnated.

  The above impregnation method of the present invention will be described in more detail with reference to examples. The impregnating material and cosolvent used in the examples and the evaluation methods performed in the examples are as follows.

[Impregnating material]
・ Water and oil repellent "Unidyne TG-656" manufactured by Daikin Industries, Ltd.
A perfluoroalkyl group-containing copolymer is contained 15% by weight in mineral spirits. The peak molecular weight in GPC measurement of “Unidyne TG-656” was determined as follows. 15 g of “Unidyne TG-656” was added to 100 ml of ethanol and stirred, and the white precipitated polymer was recovered by decantation. Washing with ethanol and separation by filtration were repeated three times and sufficiently dried to obtain 1.43 g (yield 64%) of solid content from which mineral spirits were removed from “Unidyne TG-656”. 20 mg of the above-mentioned solid content was dissolved in 10 ml of chloroform, and 25 μl of the obtained sample solution was injected at a concentration of 2 mg / ml to obtain a GPC curve. Moreover, standard polystyrene (molecular weight 500, 2,500, 10,200, 37,900, 96,400, 427,000, 1,090,000 and 5,480,000) is used as a molecular weight standard substance, and the elution time is adjusted. A calibration curve was obtained by plotting the logarithm of molecular weight. Using this calibration curve, a molecular weight in terms of polystyrene calculated from the elution time at the peak top of the obtained GPC curve was obtained. Other detailed conditions are described below. As a result of the measurement, the obtained GPC curve had two peaks, and the elution times at the peak tops were 9.3 minutes and 8.8 minutes, respectively. The peak molecular weights in terms of polystyrene calculated from the elution time were 36,400 and 85,100, respectively.
GPC equipment: LC-10 series manufactured by Shimadzu Corporation Pump: LC-10AD
Auto Injector: SIL-10AD
Detector: RID-10A
Refractive index detector
SPD-10AD
UV-VISdetector 280nm
Column oven: CTO-10A
Column temperature: 40 ° C
Column pressure: 10 kgf / cm ²
Column: Shimadzu Corporation Shim-PackGPC-80M
Elution solvent: Chloroform Elution flow rate: 1 ml / min

[Co-solvent]
Normal paraffin “Nikko White N-10” manufactured by Nikko Petrochemical Co., Ltd.
Solubility in 100 ml of water at 20 ° C .: 0.005 g / 100 ml
Boiling point: 169-173 ° C
・ Methyl isobutyl ketone (hereinafter may be abbreviated as MIBK)
Made by Daishin Chemical Co., Ltd. Purity 99.9%
Solubility in 100 ml of water at 20 ° C .: 1.9 g / 100 ml
Boiling point: 116 ° C
・ Acetone Daishin Chemical Co., Ltd. Purity 99.7%
Solubility in 100 ml of water at 20 ° C .: miscible with 20 ° C. water in any proportion Boiling point: 56 ° C.
・ Ethanol made by Nippon Alcohol Sales Co., Ltd. Specific alcohol 99 ° C or more, primary fermentation Solubility in 100 ml of water at 20 ° C: miscible with 20 ° C water at an arbitrary ratio
・ Mineral spirit (included in “Unidyne TG-656”)
Solubility in 100 ml of water at 20 ° C .: less than 1 g / 100 ml Boiling point: 130-200 ° C.

[Water repellency test]
A water repellency test (spray test) was conducted in accordance with JIS L1092. A test piece 120 mm long and 50 mm wide is taken from the leather of the sample, attached to the test piece holding frame so as not to cause wrinkles, and using a water-repellent test device, the center of the spray is aligned with the center of the holding frame, 250 ml was placed in a glass funnel and sprayed on the test piece in a required time of 25-30 seconds. Next, remove the holding frame from the table, keep it horizontally at one end, and lightly place the other side of the test piece face down on a hard object. Drops of water. The wet state of the test piece was scored according to the following criteria while attached to the protective frame.
Evaluation: Standard 100 points: No wetness or water droplet adhesion on the surface.
90 points: those which do not get wet on the surface, but show adhesion of small water droplets.
80 points: those showing small individual water droplets on the surface.
70 points: Shows wetness on half of the surface, with small individual wetness penetrating the fabric.
50 points: Wet on the entire surface.
0 point: The front and back surfaces are all wet.

[Internal water repellency]
The central part in the thickness direction of the leather sample was sliced parallel to the leather surface, 0.3 ml of water was dropped inside the leather, and the state of water absorption was observed visually. The internal water repellency was evaluated according to the following criteria. In addition, in order to see the reproducibility of evaluation, observation was performed twice.
Evaluation: Standard ○: The dripped water was not absorbed by the leather until the evaporation was completed.
X: The dripped water was absorbed into the leather before the evaporation was completed.

[Water absorption rate]
Cut the sample leather into a 30mm square, immerse it in 100ml of water overnight, take it with a paper towel "Kim Towel" and gently press it to remove excess water droplets, then measure the leather weight immediately after the impregnation treatment did. Then, it put into 37 degreeC oven and measured the weight of the leather for every elapsed time. Here, based on the weight of the leather before immersion, the ratio of the weight increase of the leather sample was determined as the water absorption rate (%).

Example 1
A 120-ml impregnation tank having a stirring blade with a propeller attached to the tip of the rotating shaft and a cylindrical stainless steel wire mesh arranged so as to surround it was used. Natural leather (cowhide, weight 4 g, thickness 1.5 mm, basis weight 667 g / m ² ) cut into 120 mm (length) × 50 mm (width) as a base material was wound around a stainless steel wire mesh. After closing the lid of the tank, the valve was opened, carbon dioxide was supplied into the tank with a supply pump, and the impregnation tank was heated with a heater to bring the impregnation tank into a supercritical state at 35 ° C. and 20 MPa. Gas was released from the back pressure valve while supplying carbon dioxide with a supply pump, and carbon dioxide was allowed to flow for 1 hour at a flow rate of 5 ml / min to remove the oils and fats on the base material. Meanwhile, the stirring blade was rotated by a motor to stir the supercritical carbon dioxide fluid, and the inside of the impregnation treatment tank was maintained at 35 ° C. and 20 MPa. After opening the back pressure valve and discharging the carbon dioxide to return to atmospheric pressure, the water / oil repellent “Unidyne TG-656” was added at a unit volume of 3 g / L of impregnation treatment tank (addition of impregnation substance) Normal paraffin “Nikko White N-10” was mixed so that the content of the co-solvent was 3% so that the amount was 0.45 g / L, and the content of the co-solvent was 0.32%. The solution was placed in a stainless steel dish placed under the stirring blade in the tank. At this time, the mixed solution was transparent. Since both the mineral spirit and “Nikko White N-10” included in “Unidyne TG-656” are co-solvents, the total content of co-solvents is 3.32%. Carbon dioxide was supplied again, the inside of the tank was pressurized to 35 ° C. and 20 MPa, and the treatment was performed for 2 hours while rotating the stirring blade. Thereafter, the temperature was once lowered to 25 ° C. so as not to be in a supercritical state, and then the back pressure valve was opened to discharge carbon dioxide to return to atmospheric pressure, and the leather was taken out. When the obtained leather was subjected to a water repellency test, the water repellency was as good as 100 points. When the internal water repellency was evaluated, the water droplets were good because they were not absorbed by the leather until evaporation. Moreover, when the water absorption rate was evaluated, the water absorption rate immediately after completion of the immersion treatment was 70.2%. FIG. 1 shows changes with time in water absorption during drying. From this, it was shown that the water absorption becomes 0% 90 minutes after the start of drying. Moreover, the texture of the obtained leather hardly changed before and after the impregnation treatment. The impregnation treatment conditions and evaluation results are summarized in Table 1.

Example 2
15 g of natural leather (sheep leather) golf gloves (manufactured by Casco Co., Ltd., basis weight 253 g / m ² ) were placed as a base material in an impregnation treatment tank having a capacity of 500 ml. After closing the lid of the tank, the valve was opened, carbon dioxide was supplied into the tank with a supply pump, and the impregnation treatment tank was heated with a heater to a supercritical state of 35 ° C. and 20 MPa. Gas was released from the back pressure valve while supplying carbon dioxide with a supply pump, and carbon dioxide was circulated for 1 hour at a flow rate of 10 ml / min to remove the fats and oils of the base material. Meanwhile, a supercritical carbon dioxide fluid was circulated using a circulation pump, and the inside of the impregnation treatment tank was maintained at 35 ° C. and 20 MPa. After opening the back pressure valve to discharge carbon dioxide and reducing the pressure, carbon dioxide was again supplied into the tank by the supply pump, and the inside of the impregnation treatment tank was brought to a supercritical state of 35 ° C. and 20 MPa. Addition amount of water / oil repellent “Unidyne TG-656” per unit volume of impregnation treatment tank is 3 g / L (impregnation substance addition amount 0.45 g / L, co-solvent content 0.32%) Thus, the solution which mixed both the normal paraffin "Nikko white N-10" was prepared so that the content rate of a cosolvent might be 3%. At this time, the mixed solution was transparent. The solution was placed in a beaker and poured into the tank using a co-solvent pump. Since both the mineral spirit and “Nikko White N-10” included in “Unidyne TG-656” are co-solvents, the total content of co-solvents is 3.32%. After the injection, the treatment was performed at 35 ° C. and 20 MPa for 2 hours while operating the circulation pump. Thereafter, the temperature was lowered to 25 ° C. so as not to be in a supercritical state, the back pressure valve was opened, carbon dioxide was discharged to return to atmospheric pressure, and the gloves were taken out. The texture of the obtained glove hardly changed before and after the impregnation treatment. Table 1 summarizes the impregnation treatment conditions, the water repellency test of the obtained glove, and the water absorption evaluation results immediately after the end of the immersion treatment.

Example 3
Impregnation treatment was performed using the impregnation treatment apparatus shown in FIG. 1 kg of natural leather (sheep leather) golf gloves (manufactured by Casco Co., Ltd., 15 g, weight 253 g / m ² ) placed in a laundry net were placed in a rotating basket 2 in an impregnation treatment tank 1 having a capacity of 30 L. After the door of the impregnation tank 1 is closed, the valves 3 and 4 are opened, and carbon dioxide is supplied from the storage tank 5 into the impregnation tank 1 via the cooler 6, the supply pump 7 and the preheater 8, The inside of the processing tank 1 was set to a supercritical state of 35 ° C. and 18 MPa. Carbon dioxide was allowed to flow through valve 4 and flowed out of valve 9 to circulate at a flow rate of 0.5 L / min for 1 hour to remove oil and fat. In the meantime, the inside of the impregnation tank 1 was maintained at 35 ° C. and 18 MPa while rotating the rotating basket 2. After the carbon dioxide was discharged through the valve 9 and decompressed, it was separated into carbon dioxide gas and fats and oils in the gas separation layer 10. Carbon dioxide was again supplied into the impregnation treatment tank 1, and the inside of the impregnation treatment tank 1 was brought into a supercritical state at 35 ° C. and 18 MPa. Thereafter, the water / oil repellent “Unidyne TG-656” was added in an amount of 3 g / L per unit volume of the impregnation treatment tank (impregnated material added amount 0.45 g / L, co-solvent content 0.32%). Thus, a solution was prepared by mixing normal paraffin “Nikko White N-10” with a co-solvent content of 3%. At this time, the mixed solution was transparent. The solution was put into a beaker 11, the valve 12 was opened, and the cosolvent pump 13 was used to inject it into the tank. Since both the mineral spirit and “Nikko White N-10” included in “Unidyne TG-656” are co-solvents, the total content of co-solvents is 3.32%. After the injection, the treatment was performed at 35 ° C. and 18 MPa for 2 hours while rotating the rotating basket 2. Thereafter, the temperature was lowered to 25 ° C. so as not to be in a supercritical state, and then carbon dioxide was discharged through the valve 9 to return to atmospheric pressure, and the gloves were taken out. Supercritical carbon dioxide discharged through the valve 9 was introduced into the gas separation tank 10 and separated into carbon dioxide gas, impregnated material and cosolvent. The carbon dioxide gas derived from the gas separation tank 10 is compressed by the compressor 14 and then stored in the storage tank 5 for reuse through the cooler 15. When the remaining amount of carbon dioxide in the storage tank 5 decreases, the valve 16 is opened and carbon dioxide is supplied from the carbon dioxide cylinder 17. The texture of the obtained glove hardly changed before and after the impregnation treatment. Table 1 summarizes the impregnation treatment conditions, the water repellency test of the obtained glove, and the water absorption evaluation result immediately after the end of the immersion treatment.

Example 4
In Example 1, instead of using “Unidyne TG-656” and “Nikko White N-10”, only “Unidyne TG-656” was used. Removal and impregnation treatment were performed. Here, the mineral spirit contained in “Unidyne TG-656” is a co-solvent. Therefore, the content of the co-solvent is 0.32%. Table 1 summarizes the impregnation treatment conditions, the water repellency test of the obtained leather, the internal water repellency, and the water absorption evaluation results immediately after the end of the immersion treatment. Further, it was found from the time-dependent change in the water absorption rate shown in FIG. 1 that the water absorption rate becomes 0% 200 minutes after the start of drying. The texture of the obtained leather hardly changed before and after the impregnation treatment.

Example 5
Mineral spirit was removed from “Unidyne TG-656” by the same method as when measuring the molecular weight of “Unidyne TG-656” to obtain a solid (impregnated material). The impregnated material was previously solidified in methyl isobutyl ketone so that the content of the co-solvent was 3% so that the addition amount per unit volume of the impregnation treatment tank was 0.5 g / L. A solution in which the minutes were dissolved was prepared. The solid content was soluble in methyl isobutyl ketone. In Example 1, instead of using “Unidyne TG-656” and “Nikko White N-10”, leather fats and oils were removed and impregnated in the same manner as in Example 1 except that only the above solution was used. Processed. The texture of the obtained leather hardly changed before and after the impregnation treatment. Table 1 summarizes the impregnation treatment conditions, the water repellency test of the obtained leather, the internal water repellency, and the water absorption evaluation results immediately after the end of the immersion treatment. Here, since methyl isobutyl ketone emits an odor at the time of handling, it may not necessarily be preferable from a work environment side.

Comparative Example 1
In Example 5, the removal and impregnation of the fat of natural leather were carried out in the same manner except for not adding any co-solvent as in Example 5. The texture of the obtained leather hardly changed before and after the impregnation treatment. Table 1 summarizes the impregnation treatment conditions, the water repellency test of the obtained leather, the internal water repellency, and the water absorption evaluation results immediately after the end of the immersion treatment.

Comparative Example 2
In Example 5, instead of using methyl isobutyl ketone, the content of the co-solvent was 3% so that the solid content was 0.5 g / L per unit volume of the impregnation treatment tank. Thus, the oil and fat removal and impregnation treatment of leather were performed in the same manner as in Example 5 except that a solution in which solid content was previously dispersed in acetone was used. The solid content did not dissolve in acetone. The texture of the obtained leather hardly changed before and after the impregnation treatment. Table 1 summarizes the impregnation treatment conditions, the water repellency test of the obtained leather, the internal water repellency, and the water absorption evaluation results immediately after the end of the immersion treatment.

Comparative Example 3
In Example 5, instead of using methyl isobutyl ketone, ethanol was used as a co-solvent content of 3% so that the solid content was 0.5 g / L per unit volume of the impregnation treatment tank. Thus, removal of fats and oils from leather and impregnation were performed in the same manner as in Example 5 except that a solution in which a solid content was previously dispersed in ethanol was used. The solid content did not dissolve in ethanol. The texture of the obtained leather hardly changed before and after the impregnation treatment. Table 1 summarizes the impregnation treatment conditions, the water repellency test of the obtained leather, the internal water repellency, and the water absorption evaluation results immediately after the end of the immersion treatment.

Comparative Example 4
First, in the same manner as in Example 1, natural fats and oils were removed in a supercritical carbon dioxide fluid at 35 ° C. and 20 MPa. After opening the back pressure valve and discharging the carbon dioxide to return to atmospheric pressure, the water / oil repellent “Unidyne TG-656” was added at a unit volume of 3 g / L of impregnation treatment tank (addition of impregnation substance) The amount was 0.45 g / L, and the co-solvent content was 0.32%), and the mixture was placed in a stainless steel dish placed under the stirring blade in the tank. Here, the mineral spirit contained in “Unidyne TG-656” is a co-solvent. Therefore, the content of the co-solvent is 0.32%. Thereafter, the carbon dioxide in the tank was treated as a liquid at 19 ° C. and 20 MPa for 2 hours with stirring. After that, the back pressure valve was opened to discharge carbon dioxide and returned to atmospheric pressure, and then the leather was taken out. The texture of the obtained leather hardly changed before and after the impregnation treatment. Table 1 summarizes the impregnation treatment conditions, the water repellency test of the obtained leather, the internal water repellency, and the water absorption evaluation results immediately after the end of the immersion treatment.

Comparative Example 5
120 ml of “Nikko White N-10” was placed in a 200 ml beaker, and “Unidyne TG-656” was added to 3 g / L to prepare a solution. Natural leather (made of cowhide, weight 4 g, thickness 1.5 mm, basis weight 667 g / m ² ) cut into 120 mm (length) × 50 mm (width) was added to the solution, and immersed and stirred for 2 hours. After removing the leather from the solution, the solvent was evaporated at room temperature for 24 hours. Table 1 summarizes the impregnation treatment conditions, the water repellency test of the obtained leather, the internal water repellency, and the water absorption evaluation results immediately after the end of the immersion treatment. Further, it was found from the time-dependent change in the water absorption rate shown in FIG. 1 that it takes 200 minutes or more for the water absorption rate to reach 0% from the start of drying. The texture of the obtained leather became wrinkled and deteriorated as compared with that before the impregnation treatment.

Comparative Example 6
About natural leather (cowhide, weight 4 g, thickness 1.5 mm, basis weight 667 g / m ² ) cut to 120 mm (length) x 50 mm (width), the water repellency test of natural leather in an untreated state, internal water repellency Table 1 summarizes the evaluation results of the water absorption immediately after completion of the immersion treatment. Further, it was found from the time-dependent change in the water absorption rate shown in FIG. 1 that it takes 200 minutes or more for the water absorption rate to reach 0% from the start of drying.

Comparative Example 7
Table 1 summarizes the results of natural water (sheep leather) golf gloves (manufactured by Casco Co., Ltd., basis weight 253 g / m ² ), the water repellency test in an untreated state and the water absorption rate immediately after the end of the immersion treatment. Show.

As shown in Table 1, when the impregnation treatment was performed using a co-solvent having a solubility in 100 ml of water at 20 ° C. of 2 g / 100 ml or less (Examples 1 to 5), the water repellency and internal repellency were increased. It was found that the water was excellent and the texture hardly changed before and after the impregnation treatment. The water absorption rate immediately after completion of the immersion treatment was low, and accordingly, the time required for the water absorption rate to reach 0% was shortened, indicating that it was quick drying. On the other hand, when no cosolvent is used (Comparative Example 1), even when used, a cosolvent having a solubility in 100 ml of water at 20 ° C. exceeding 100 g / 100 ml (Comparative Examples 2 and 3) and liquefied carbon dioxide are used. When used (Comparative Example 4), the water repellency and internal water repellency were poor. In addition, when the impregnation treatment was performed using a solvent as a medium (Comparative Example 5), it was shown that all of the water repellency, internal water repellency and texture were inferior.
From these results, it was shown that by applying the impregnation method of the present invention to natural leather, the inside of the base material can be impregnated with the water repellent without impairing the texture of the base material.

It is the graph which showed the time-dependent change of the water absorption rate. FIG. 6 is a process flow diagram of the apparatus according to the third embodiment.

DESCRIPTION OF SYMBOLS 1 Impregnation tank 2 Rotating basket 3 Valve 4 Valve 5 Storage tank 6 Cooler 7 Supply pump 8 Preheater 9 Valve 10 Gas separation layer 11 Beaker 12 Valve 13 Cosolvent pump 14 Compressor 15 Cooler 16 Valve 17 Carbon dioxide cylinder

Claims (1)

A method of impregnating a base material made of natural leather with an impregnating substance that is at least one selected from the group consisting of a water repellent, a waterproofing agent, and an oil repellent in supercritical carbon dioxide, normal paraffin peak molecular weight of Ri 1000 or more fluorine compound or silicone compound der, and solubility in water 100ml at 20 ° C. is less cosolvent 2 g / 100ml at the GPC measurement, mineral spirits, 1 of methyl isobutyl ketone The species or a mixture of two or more species is 0.01 to 10% in the supercritical carbon dioxide (provided that the content of the cosolvent is the volume of the added cosolvent under normal pressure divided by the volume of the supercritical fluid. to contain value value) multiplied by 100 to dissolution were to supply a solution obtained by previously dissolving the impregnation material in said co-solvent in the impregnation treatment tank A method for impregnating the natural leather with a water repellent , which comprises impregnating the impregnated substance into the natural leather in a separate bath .

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