Fiber product including sizing agent, sizing agent, method for producing fiber product including sizing agent, and method for producing fiber product

Abstract

A fiber product including a sizing agent, wherein the sizing agent contains an alkenyl succinic acid ester of a starch decomposition product.

Description

Sized textile product, sizing agent, method for manufacturing sized textile product, and method for manufacturing textile product

[0001] The present invention relates to a sized textile product, a sizing agent, a method for producing a sized textile product, and a method for producing a textile product.

[0002] Generally, woven fabrics, such as cotton products, are made by interlacing warp and weft threads. Therefore, the process of making a woven fabric begins with separating the raw warp and weft threads. The separated raw warp and weft threads are then passed through various processes. Finally, they are woven on a loom, and the finished fabric is inspected and sent to the finishing process. The main processes in cotton product manufacturing are spinning, sizing, weaving, desizing / scouring / bleaching, dyeing, and finishing. Among these processes, sizing, desizing / scouring, and dyeing consume large amounts of water and also generate large amounts of wastewater. It is estimated that wastewater generated during clothing manufacturing accounts for 20% of the world's total wastewater. Reducing environmental impact is a major global issue, and environmentally friendly manufacturing processes that address these wastewater issues are needed. Among the above processes, the desizing process after weaving significantly impacts the subsequent dyeing and finishing processes, as well as product quality. Conventional sizing agents, which are the target of this desizing process, are designed for water-based desizing.

[0003] It is also known that supercritical carbon dioxide is used for textile processing. The supercritical state occurs when a compound exceeds its specific critical temperature (Tc) and critical pressure (Tp). This state is called a supercritical fluid and has properties intermediate between those of a gas and a liquid. As shown in Figure 1, carbon dioxide can reach a supercritical state under relatively mild conditions, with a Tc of 31.1°C and a Tp of 7.38 MPa. It has the advantages of being non-explosive, non-toxic, highly safe, inexpensive, and readily available. Supercritical carbon dioxide also has the following characteristics: (1) its density fluctuates significantly with small changes in pressure near its critical temperature; (2) its low viscosity and high diffusivity result in excellent transport properties and high penetration into materials; (3) its high thermal conductivity results in rapid heat transfer; (4) its solvation effect results in rapid reaction rates; (5) its dielectric constant is smaller than that of water, making it comparable to that of conventional nonpolar organic solvents, making it a good solvent for nonpolar organic substances; and (5) the carbon dioxide can be recovered and reused.

[0004] The present inventors believed that by using supercritical carbon dioxide as a solvent in place of the water conventionally used in the desizing process of textiles, it would be possible to realize an environmentally friendly textile manufacturing process that would solve the wastewater problem. The conventional sizing agent to be treated in the desizing process has traditionally been a starch-containing sizing agent. However, after extensive research, the present inventors found that starch-containing sizing agents are designed for desizing using water, and therefore are unsuitable for desizing using supercritical carbon dioxide. As described above, there is a need for a sizing-applied textile product that is suitable for desizing using supercritical carbon dioxide.

[0005] An object of the present invention is to provide a sizing agent-coated textile product suitable for desizing using supercritical carbon dioxide.

[0006] As a result of intensive research aimed at solving the above-mentioned problems, the present inventors discovered that the above-mentioned problems can be solved by using a sizing agent containing an alkenyl succinate ester of a starch hydrolysate, and thus completed the present invention. Specific aspects of the present invention are as follows.

[0007] [1] A sizing textile, wherein the sizing agent comprises an alkenyl succinate ester of a starch hydrolysate. [2] The sizing textile according to [1], wherein the alkenyl succinate ester of a starch hydrolysate comprises an octenyl succinate ester of dextrin, an octenyl succinate ester of maltose, a dodecenyl succinate ester of maltose, or a combination thereof. [3] The sizing textile according to [1] or [2], wherein the alkenyl succinate ester of a starch hydrolysate has an alkenyl succinic acid content of 5 to 50% by weight. [4] The sizing textile according to any of [1] to [3], wherein the starch hydrolysate, which is a component of the alkenyl succinate ester of a starch hydrolysate, has a DE of 5 to 80. [5] The sizing textile according to any of [1] to [4], wherein the textile comprises cotton yarn or cotton fabric. [6] A sizing textile product according to any one of [1] to [5], wherein the adhesion rate of the sizing agent to the sizing textile product is 0.1 to 10% by weight. [7] A sizing agent containing an alkenyl succinate ester of a starch hydrolysate, for producing the sizing textile product according to any one of [1] to [6]. [8] A method for producing the sizing textile product according to any one of [1] to [6], comprising a step of bringing a fluid containing the sizing agent into contact with a textile product to size the textile product. [9] A method for producing a textile product from the sizing textile product according to any one of [1] to [6], comprising a step of bringing the sizing textile product into contact with a fluid containing supercritical carbon dioxide to desize the sizing textile product.

[10] The method according to [9], wherein the desizing step is carried out by batch processing or continuous processing.

[0008] The sizing-applied textile product according to one aspect of the present invention is suitable for desizing using supercritical carbon dioxide.

[0009] FIG. 1 is a temperature-pressure phase diagram of carbon dioxide. FIG. 2 is an SEM image of cotton yarn with no sizing agent attached. FIG. 3 is an SEM image of cotton yarn with alkenyl succinate ester (1), a starch hydrolysate, attached. FIG. 4 is an SEM image of cotton yarn with alkenyl succinate ester (2), a starch hydrolysate, attached. FIG. 5 is a photograph of woven fabric before treatment with a fluid containing supercritical carbon dioxide. FIG. 6 is a diagram showing an outline of an apparatus used for treatment with a fluid containing supercritical carbon dioxide. FIG. 7 is a diagram showing a jig with cotton yarn wrapped around it.

[0010] In this specification, when a numerical range is expressed using "X to Y," the range is intended to include both end values.

[0011] The sizing textile product, the sizing agent, the method for producing the sizing textile product, and the method for producing the textile product of the present invention will be described below.

[0012] 1. Sized Textiles A sized textile product according to one aspect of the present invention is a sized textile product in which the sizing agent contains an alkenyl succinate ester of a starch hydrolysate. The sized textile product according to one aspect of the present invention is suitable for desizing using supercritical carbon dioxide. In some cases, the sized textile product of this embodiment, in addition to being suitable for desizing using supercritical carbon dioxide, has high resistance to friction and / or can exhibit high tensile strength and / or can exhibit high tensile elongation.

[0013] In addition, cellulose acetate has been used as a component of sizing agents in some cases. In the sizing agent-coated textile product of the present embodiment, the use of an alkenyl succinate ester of a starch hydrolysate as a component of the sizing agent has the effect of enabling the use of cheaper water as a co-solvent compared to the case where cellulose acetate is used, and / or imparting sufficient durability and tensile strength to the textile product even when the amount of water added or applied is small.

[0014] (Sizing Agent) The sizing agent may further contain components other than the alkenyl succinate ester of the starch hydrolysate, or may contain no components other than the alkenyl succinate ester of the starch hydrolysate (the sizing agent may be composed of the alkenyl succinate ester of the starch hydrolysate). In this specification, "not containing" a specific component means that the component is not intentionally added, and does not exclude forms in which the component is contained as an impurity. The components other than the alkenyl succinate ester of the starch hydrolysate are not particularly limited, and may contain or consist of corn starch, wax, propylene glycol, polyvinyl alcohol (PVA), or a combination of two or more of these.

[0015] The adhesion rate (amount of adhesion) of sizing agent to a sizing-coated textile product is not particularly limited, but is preferably 0.1 to 10% by weight, more preferably 1 to 8% by weight, most preferably 3 to 8% by weight, and can be 5 to 7.5% by weight. When the adhesion rate of sizing agent is within the above numerical range, pilling due to friction between threads or between threads and metal is less likely to occur, and thread breakage is reduced, thereby improving weaving efficiency. The adhesion amount of sizing agent to a sizing-coated textile product can be calculated based on the method and procedure described in (5-1) of 1. [Examples] below.

[0016] The size agent is not particularly limited, but may be a size agent for warp threads of a woven fabric.

[0017] (Alkenyl succinate esters of starch hydrolysates) Alkenyl succinate esters of starch hydrolysates are esters of starch hydrolysates and alkenyl succinic acids obtained by esterifying starch hydrolysates with alkenyl succinic acids. The esterification reaction is a reaction between some or all of the hydroxy groups (—OH) of the starch hydrolysates and the carboxylic acid groups or carboxylic anhydride groups of the alkenyl succinic acids. It is believed that the introduction of the alkenyl succinic acid structure into the starch hydrolysate molecules increases the hydrophobicity of the molecules.

[0018] The alkenylsuccinic acid content (wt%) (particularly, the octenylsuccinic acid content (wt%)) in the alkenylsuccinic acid ester of a starch hydrolysate is not particularly limited, and is preferably 5 to 50 wt%, more preferably 10 to 40 wt%, and most preferably 20 to 30 wt%. Having the alkenylsuccinic acid content (wt%) within the above range improves the hydrophobicity of the alkenylsuccinic acid ester of the starch hydrolysate. The alkenylsuccinic acid content (wt%) can be calculated based on the procedures and formulas described in "D. Component Specifications and Storage Standards," "Starch Sodium Octenylsuccinate," and "Purity Test (2)" (pages 471 and 472) of the 9th Edition of the Official Specification of Food Additives (published by the Ministry of Health, Labour and Welfare), as described in the "Examples" section below.

[0019] The degree of substitution (DS) of the alkenyl succinate group in the alkenyl succinate ester of the starch hydrolysate (the average number of alkenyl succinate groups present per glucose ring unit in the alkenyl succinate ester of the starch hydrolysate) is not particularly limited, but is preferably 0.05 to 0.7, more preferably 0.1 to 0.5, and most preferably 0.15 to 0.3. When the degree of substitution of the alkenyl succinate group is within the above range, the hydrophobicity of the alkenyl succinate ester of the starch hydrolysate is improved, and the solubility in supercritical carbon dioxide is also improved.

[0020] The molecular weight of the alkenyl succinate ester of a starch hydrolysate is not particularly limited, and is preferably 200 to 3,000, more preferably 300 to 2,000, and most preferably 400 to 1,500. When the molecular weight is within the above numerical range, the solubility of the alkenyl succinate ester of a starch hydrolysate in supercritical carbon dioxide is improved. The molecular weight of the alkenyl succinate ester of a starch hydrolysate can be calculated as a theoretical value based on the molecular weights of the starch hydrolysate and alkenyl succinic acid, which are raw materials, and the degree of substitution (DS) of the alkenyl succinate group described above.

[0021] The starch hydrolysate, which is a component of the alkenyl succinate ester of the starch hydrolysate, is obtained by hydrolyzing starch with an acid, an enzyme, or the like. The starch hydrolysate in this embodiment is not particularly limited, but may contain or consist of maltose, dextrin, maltooligosaccharide, maltotriose, glucose, or the like, or a combination of two or more of these. Among these, maltose, dextrin, or a combination thereof is preferred. The use of maltose, dextrin, or a combination thereof improves the solubility of the alkenyl succinate ester of the starch hydrolysate in supercritical carbon dioxide.

[0022] DE (dextrose equivalent) is an index that indicates the degree of decomposition of starch hydrolysates. The DE of the starch hydrolysates of this embodiment is not particularly limited, and is preferably 5 to 80, more preferably 10 to 70, and most preferably 15 to 60. When the DE of the starch hydrolysates is within the above-mentioned numerical range, the molecular weight of the alkenyl succinate esters of the starch hydrolysates is reduced, thereby improving the solubility of the esters in supercritical carbon dioxide. The DE of the starch hydrolysates can be measured by the Lane method or the WS method.

[0023] The alkenylsuccinic acid, which is a constituent of the alkenylsuccinic acid ester of a starch hydrolysate, may or may not be in the form of an acid anhydride. The number of carbon atoms in the alkenyl group in the alkenylsuccinic acid is not particularly limited, but is preferably 1 to 30, more preferably 3 to 20, and most preferably 5 to 15. The alkenylsuccinic acid is not particularly limited, but may include or consist of octenyl succinic anhydride, decenyl succinic anhydride, dodecenyl succinic anhydride, tetradecenyl succinic anhydride, hexadecenyl succinic anhydride, octadecenyl succinic anhydride, or a combination of two or more thereof. Of these, octenyl succinic anhydride, dodecenyl succinic anhydride, or a combination thereof is preferred. By using octenyl succinic anhydride, dodecenyl succinic anhydride, or a combination thereof, the hydrophobicity of the alkenyl succinate ester of the starch hydrolysate is improved, and the solubility in supercritical carbon dioxide is also improved.

[0024] The alkenyl succinate ester of a starch hydrolysate may be any combination of the starch hydrolysate and alkenyl succinic acid described above. The alkenyl succinate ester of a starch hydrolysate may comprise or consist of octenyl succinate of dextrin, octenyl succinate of maltose, dodecenyl succinate of maltose, or a combination of two or more thereof.

[0025] An example of a method for producing an alkenyl succinate ester of a starch hydrolysate is shown below. A starch hydrolysate is dissolved in water alone or in a mixed solvent of water and an organic solvent such as alcohol or acetone, and then an alkenyl succinic anhydride is added. The mixture is reacted with stirring in the presence of a catalyst at a pH of 6 to 8, thereby producing an alkenyl succinate ester of a starch hydrolysate. Examples of the catalyst include alkali metal hydroxides such as sodium hydroxide, potassium hydroxide, and lithium hydroxide; alkali metal carbonates such as sodium carbonate, potassium carbonate, and lithium carbonate; alkali metal alkoxides such as sodium methoxide, sodium ethoxide, and potassium methoxide; ammonia; mono-, di-, or trialkylamines having an alkyl group such as methylamine, dimethylamine, trimethylamine, ethylamine, diethylamine, triethylamine, propylamine, dipropylamine, butylamine, isobutylamine, sec-butylamine, tert-butylamine, amylamine, sec-amylamine, tert-amylamine, and hexylamine; and di- or tri-alcoholamines having an alcohol group such as triethanolamine, triisopropanolamine, and diethanolamine, which may be used alone or in combination. A method for producing alkenyl succinate esters of starch hydrolysates can be carried out, for example, based on the method described in JP-A-4-273806.

[0026] When alkenyl succinic anhydride is used, the alkenyl succinic acid ester of the starch hydrolysate undergoes a ring-opening reaction with the alkenyl succinic anhydride in the presence of the catalyst, and becomes an ester bonded to the starch hydrolysate as a single ester. The other carboxylic acid in the alkenyl succinic anhydride becomes an alkali metal salt or an amine salt in the presence of the catalyst.

[0027] When preparing a conventional starch-containing paste, it is necessary to heat the starch to a high temperature in order to dissolve and gelatinize it in a solvent. On the other hand, when preparing a paste containing an alkenyl succinate ester of a starch hydrolysate according to the present embodiment, the alkenyl succinate ester of a starch hydrolysate dissolves in a solvent even at room temperature, which has the advantage that a heating step is not required.

[0028] The content of the alkenyl succinate ester of starch hydrolysate in the paste can be 100% by weight (the paste is composed of the alkenyl succinate ester of starch hydrolysate). The content of the alkenyl succinate ester of starch hydrolysate in the paste can be 80% by weight or more, 90% by weight or more, or 95% by weight or more. Furthermore, the content of the alkenyl succinate ester of starch hydrolysate in the paste can be 100% by weight or less. The above numerical ranges can be combined in any way.

[0029] (Textile Products) Examples of textile products include, but are not limited to, fibers, yarns, fabrics, etc. Examples of fibers include tow before being made into yarn. Examples of yarns include, but are not limited to, spun yarns, filament yarns, and mixed twisted yarns and blended yarns obtained by mixing and twisting these. Examples of fabrics include woven fabrics and knitted fabrics using yarns, as well as nonwoven fabrics and felts. In this embodiment, it is preferable to use yarns as the textile product, and in this case, the yarns to which the sizing agent has been applied obtained by this method can be subjected to a subsequent weaving process. The textile product can also include or consist of cotton yarns or cotton fabrics.

[0030] The type of yarn is not particularly limited, but examples include natural fibers such as plant fibers like cotton and hemp, animal fibers like silk and wool, synthetic fibers like polyester and acrylic, semi-synthetic fibers like acetate, triacetate, and promix, regenerated fibers like rayon, polynosic, cupra, and lyocell, and inorganic fibers like glass fiber, metal fiber, and carbon fiber. Two or more of these yarns may be blended or twisted together. These yarns may also be single yarns, two-ply yarns, triple-ply yarns, or yarns twisted together with four or more strands. In this embodiment, cotton yarn is preferred from the perspective of the feel of the towel. The type of fabric is not particularly limited, but may be the same as the yarn types described above.

[0031] The sizing textile product can be, but is not limited to, a sizing yarn or a sizing fabric. The sizing yarn can be, but is not limited to, the warp yarn of a woven fabric. The sizing fabric can be, but is not limited to, a woven fabric including a sizing warp yarn (having a sizing agent attached thereto) containing the alkenyl succinate ester of a starch hydrolysate, and a weft yarn to which no sizing agent containing the alkenyl succinate ester of a starch hydrolysate is attached. Here, the weft yarn to which no sizing agent containing the alkenyl succinate ester of a starch hydrolysate is attached refers to a weft yarn to which no sizing agent has been actively attached. Therefore, the weft yarn to which no sizing agent containing the alkenyl succinate ester of a starch hydrolysate is attached can also include a state in which the sizing warp yarn containing the alkenyl succinate ester of a starch hydrolysate comes into contact with the weft yarn, and the sizing agent from the warp yarn is transferred to the weft yarn. Both the warp yarns with a sizing agent containing the alkenyl succinate ester of a starch hydrolysate (a sizing agent attached thereto) and the weft yarns without a sizing agent containing the alkenyl succinate ester of a starch hydrolysate attached thereto can be cotton yarns.

[0032] 2. Sizing Agent A sizing agent according to one aspect of the present invention is a sizing agent containing an alkenyl succinate ester of a starch hydrolysate for producing the sizing-coated textile product described above in 1. In the sizing agent of this embodiment, the respective components of the sizing agent, the alkenyl succinate ester of a starch hydrolysate, the type and content of the textile product, etc. can be the same as those described above in 1.

[0033] As mentioned in 1 above, the sizing agent can be a sizing agent for warp threads of a woven fabric.

[0034] 3. Method for Producing a Sized Textile Product A method for producing a sized textile product according to one aspect of the present invention is the method for producing a sized textile product described in 1 above, and includes a step of bringing a fluid containing the sizing agent into contact with a textile product to size the textile product.

[0035] In the method of this embodiment, the types, contents, and other components of the sizing agent, alkenyl succinate ester of starch hydrolysate, and textiles can be the same as those described in 1 above.

[0036] In this embodiment, the treatment conditions when the fluid containing the sizing agent is brought into contact with the textile product are not particularly limited, but from the viewpoint of improving sizing properties, the temperature can be in the range of 0 to 100°C, preferably in the range of 0 to 75°C, and most preferably in the range of 0 to 55°C. Furthermore, from the viewpoint of improving sizing properties, the pressure is preferably 0.01 to 0.2 MPa. Furthermore, from the viewpoint of improving sizing properties, the treatment time is preferably about 60 minutes per 450 kg of textile product. The process of bringing the fluid containing the sizing agent into contact with the textile product can be performed by batch processing.

[0037] The amount of sizing agent used is not particularly limited, but for example, when cotton yarn is used as the textile product, it is preferable to use 0.03 to 0.07 g of sizing agent per 1 g of cotton yarn in order to improve sizing properties.

[0038] The content of the alkenyl succinate ester of starch hydrolysate in the sizing fluid is not particularly limited, but is preferably 0.1 to 10 wt %, more preferably 0.5 to 7 wt %, and most preferably 1 to 5 wt %. When the content of the alkenyl succinate ester of starch hydrolysate in the fluid is within the above range, the sizing concentration and adhesion amount are both minimized, while the sizing permeability into the yarn is good, leading to improved weaving efficiency.

[0039] In this embodiment, the fluid containing the adhesive may further contain, but is not limited to, a solvent. The solvent may include, or consist of, water, a glycol ether-based solvent, an aqueous solvent such as a lower alcohol, glycerin, polyethylene glycol, polypropylene glycol, DMSO, DMF, benzyl alcohol, N-methyl-2-pyrrolidone, or a combination of two or more of these. Among these, water is preferred. By including water in the fluid, excellent solubility and appropriate viscosity can be achieved. The glycol ether-based solvent may include, but is not limited to, ethylene glycol monobutyl ether (2-butoxyethanol) (EGME), diethylene glycol mono-2-ethylhexyl ether, ethylene glycol monophenyl ether, 2-methylpentane-2,4-diol, diethylene glycol monohexyl ether, diethylene glycol dibutyl ether, triethylene glycol monobutyl ether, or a combination of two or more of these. Among these, EGME is preferred. The lower alcohol may include, but is not limited to, methanol, ethanol, or a combination of these. The content of the solvent in the fluid containing the adhesive is not particularly limited, but is preferably 50 to 99 wt %, more preferably 65 to 95 wt %, and most preferably 80 to 95 wt %. When the content of the solvent in the fluid containing the adhesive is within the above range, the solubility of the solid content is improved.

[0040] In this embodiment, when a solvent is used, the solvent can be sent into the processing vessel.

[0041] When a solvent is used, the ratio (mol) of the solvent to 1 to 5 g of the adhesive is not particularly limited, but from the viewpoint of improving sizing properties, 1 to 6 mol is preferred.

[0042] The method of this embodiment can be used as a sizing process, which is one of the fiber processing steps, and can also be used in combination with other fiber processing steps such as spinning, weaving, desizing / refining / bleaching, dyeing, and finishing. Furthermore, the method for producing a sizing-applied fiber product of this embodiment can be combined with a method for producing a fiber product from a sizing-applied fiber product, which will be described later, to form a single method or production method.

[0043] In the method of this embodiment, the step of sizing the textile product may include or consist of a step of contacting a fluid containing the sizing agent with a yarn to size the yarn. In this case, the method of this embodiment may further include a step of forming a fabric using the sized yarn to form a sized fabric. In this case, the method of this embodiment may further include or consist of a step of forming a woven fabric using the sized yarn as a warp yarn to form a sized woven fabric.

[0044] 4. Method for Producing Textiles from Sized Textiles A method for producing textiles from sized textiles according to one aspect of the present invention is the method for producing textiles from sized textiles described in 1 above, and includes a step of desizing the sized textiles by contacting the sized textiles with a fluid containing supercritical carbon dioxide. Because a sizing agent containing an alkenyl succinate ester, a starch hydrolysate, is used, the method for producing textiles from sized textiles of this embodiment can efficiently remove the sizing agent.

[0045] In the method of this embodiment, the types, contents, etc. of the starch hydrolysate, alkenyl succinate ester, and textiles may be similar to those described in 1. In this embodiment, from the viewpoint of the feel of the towel, it is preferable to use cotton yarn as the textile.

[0046] In this embodiment, the sizing agent-coated textile product is not particularly limited, but it is possible to use a product obtained by the method for producing a sizing agent-coated textile product described in 3 above.

[0047] In this embodiment, the treatment conditions when the fluid containing supercritical carbon dioxide is brought into contact with the sizing-applied textile product are not particularly limited, but from the viewpoint of improving desizing properties, the temperature can be 31 to 150°C or 40 to 120°C, the pressure can be 8 to 25 MPa or 10 to 25 MPa, and the time can be 30 to 800 minutes or 120 to 180 minutes. In this embodiment, the desizing step can be a batch process or a continuous process.

[0048] In this embodiment, the fluid containing supercritical carbon dioxide may further contain a co-solvent. By including a co-solvent in the fluid, the solubility of the glue in the solvent (including supercritical carbon dioxide and the co-solvent) can be improved, thereby improving resizing. The co-solvent is not particularly limited, and the solvents described in 3. above can be used, but it is preferable to use an aqueous solvent, a glycol ether solvent, or a combination thereof, particularly water, EGME, or a combination thereof. By using the solvent described in 3. above as the co-solvent, the solubility of the glue in the solvent (including supercritical carbon dioxide and the co-solvent) can be improved, thereby improving resizing. The above effect is particularly pronounced when water, EGME, or a combination thereof is used as the co-solvent.

[0049] In this embodiment, when a co-solvent is used, the co-solvent can be fed into the processing vessel separately from the supercritical carbon dioxide.

[0050] In this embodiment, when the desizing step is performed by batch processing and a co-solvent is used, the ratio (mol %) of the co-solvent to the supercritical carbon dioxide is not particularly limited, but is preferably 0.1 to 2 mol % from the viewpoint of improving the solubility of the sizing agent in the solvent and improving desizing properties. The volume ratio of supercritical carbon dioxide to the co-solvent is not particularly limited, but is preferably 400:1 to 10:1, more preferably 300:1 to 25:1, and most preferably 200:1 to 40:1. The volume ratio of supercritical carbon dioxide to the co-solvent can also be 150:1 to 50:1, 100:1 to 60:1, or 90:1 to 70:1.

[0051] In the present embodiment, when the desizing step is a continuous process, the flow rate of supercritical carbon dioxide into the processing vessel is not particularly limited, but from the viewpoint of improving the solubility of the sizing agent in the solvent and thereby improving the desizing properties, it is preferably 50 mL to 2000 mL, and more preferably 100 mL to 1500 mL per 1 g of fiber.

[0052] In this embodiment, when the desizing step is a continuous process and a co-solvent is used, the flow rate of the co-solvent into the processing vessel is not particularly limited, but is preferably 1 mL to 500 mL, more preferably 10 mL to 400 mL per 1 g of fiber.

[0053] The percentage of sizing agent removal after desizing using the method of this embodiment is not particularly limited, but can be, for example, 1 to 99%. The percentage of sizing agent removal can be calculated based on the procedure and method described in Section 2 (4-1) of the Examples below. In the method of this embodiment, the solubility of the sizing agent in the fluid containing supercritical carbon dioxide is not particularly limited, but is preferably 0.0001 to 0.01 g / mL, more preferably 0.001 to 0.008 g / mL, and most preferably 0.002 to 0.006 g / mL. The solubility of the sizing agent in the fluid containing supercritical carbon dioxide is not particularly limited, but can be 1 x 10 g / mL or more, 1 x 10 g / mL or more, or 1 x 10 g / mL or more. The solubility of the sizing agent in the fluid containing supercritical carbon dioxide is not particularly limited, but can be 1 g / mL or less, 1 x 10 g / mL or less, or 1 x 10 g / mL or less. The above numerical ranges can be combined arbitrarily. The solubility of the adhesive in the fluid containing supercritical carbon dioxide can be calculated based on the procedure and method described in (4-2) of Section 2 of [Examples] below.

[0054] The method of this embodiment can be used as a desizing process, which is one of the fiber processing steps, and can also be used in combination with other fiber processing steps such as spinning, weaving, sizing, scouring / bleaching, dyeing, and finishing. Furthermore, the method of producing a fiber product from a sized fiber product of this embodiment can be combined with the above-mentioned method of producing a sized fiber product to form a single method or production method.

[0055] The present invention will be specifically described below with reference to examples, but the present invention is not limited to the contents described in the examples.

[0056] 1. Measurement of physical properties or observation of surface condition of sizing agent or sizing-coated textile product (1) Preparation of alkenyl succinate ester of starch hydrolysate [Alkenyl succinate ester of starch hydrolysate (1)] A reactor was charged with 500 g of water and 250 g of dextrin TK-16 (manufactured by Matsutani Chemical Industry Co., Ltd., DE: 18, powder) (the dextrin is formed from approximately five glucose molecules, and therefore, from the molecular weight of glucose: approximately 180 g / mol, the molecular weight of the dextrin can be estimated to be approximately 900 g / mol). The dextrin was dissolved in water at a temperature of 30°C to obtain an aqueous solution. While the pH of the resulting aqueous solution was maintained at 7.5 to 8.5 by adding a 3% sodium hydroxide solution, 250 g of octenyl succinic anhydride (RIKACID OSA, manufactured by New Japan Chemical Co., Ltd., liquid) was added dropwise to the aqueous solution over 1 hour at 30°C. After the dropwise addition of octenyl succinic anhydride, the mixture was allowed to react for an additional 3 hours at 30°C to obtain a solution of the reaction product. The resulting solution was subjected to vacuum freeze-drying to thoroughly remove water, ultimately yielding 550 g of a powder of octenyl succinate ester of dextrin (hereinafter referred to as "alkenyl succinate ester of starch hydrolysate (1)").

[0057] The octenylsuccinic acid content (wt%) of the obtained sample of alkenylsuccinate ester (1) (powder) of starch hydrolysates was calculated to be 25 wt% based on the procedures and formulas described in "D. Compositional Specifications and Storage Standards," "Starch Sodium Octenylsuccinate," and "Purity Test (2)" (pages 471 and 472) of the 9th Edition of the Official Specification of Food Additives (published by the Ministry of Health, Labour and Welfare). The degree of substitution (DS) of the alkenylsuccinate ester (1) of starch hydrolysates was calculated based on the obtained octenylsuccinic acid content (wt%) to be 0.23. Furthermore, based on the obtained DS value of 0.23, it is considered that one molecule of the used dextrin (approximately five glucose molecules) is bound to 0.23 × 5 = 1.15 molecules of octenyl succinic anhydride (molecular weight: approximately 210), and therefore the molecular weight (theoretical value) of the alkenyl succinate ester (1), a starch hydrolyzate, can be calculated to be approximately 1,100.

[0058] [Alkenyl succinate ester of starch hydrolysate (2)] 550 g of a powder of octenyl succinate ester of maltose (hereinafter referred to as "alkenyl succinate ester of starch hydrolysate (2)") was finally obtained in the same manner as in the preparation of the above-mentioned [Alkenyl succinate ester of starch hydrolysate (1)], except that 250 g of maltose (reagent, purity: 99.9%, Fujifilm Wako Pure Chemical Industries, Ltd., DE: approximately 50) (the maltose is formed from approximately two glucose molecules, and therefore the molecular weight of the maltose can be estimated to be approximately 360 g / mol from the molecular weight of glucose: approximately 180 g / mol) was used instead of 250 g of dextrin TK-16. The octenylsuccinic acid content (wt%) of the obtained sample of alkenyl succinate ester (2) (powder) of starch hydrolysate was calculated in the same manner as in the above-mentioned [Alkenyl succinate ester (1) of starch hydrolysate], and was found to be 25 wt%. Based on the obtained octenylsuccinic acid content (wt%), the degree of substitution (DS) of the alkenyl succinate ester (2) of starch hydrolysate was calculated to be 0.23. Furthermore, based on the obtained DS value of 0.23, it is believed that one molecule of maltose (approximately two glucose molecules) used is bound to 0.23 x 2 = 0.46 molecules of octenyl succinic anhydride (molecular weight: approximately 210), and therefore the molecular weight (theoretical value) of the alkenyl succinate ester (2) of starch hydrolysate can be calculated to be approximately 450.

[0059] [Alkenyl succinate ester of starch hydrolysate (3)] 500 g of water and 250 g of maltose (reagent, purity: 99.9%, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., DE: approximately 50) were charged into a reactor, and the maltose was dissolved in water at 50°C to obtain an aqueous solution. While the pH of the resulting aqueous solution was maintained at 7.5 to 8.5 by adding a 3% sodium hydroxide solution, 250 g of dodecenyl succinic anhydride (RIKACID DDSA, manufactured by New Japan Chemical Co., Ltd., liquid) was added dropwise to the aqueous solution over 1 hour at 50°C. After the dropwise addition of dodecenyl succinic anhydride, the mixture was allowed to react for an additional 7 hours at 50°C to obtain a solution of the reaction product. The resulting solution was subjected to vacuum freeze-drying to thoroughly remove water, ultimately yielding 550 g of powder of dodecenyl succinate ester of maltose (hereinafter referred to as "alkenyl succinate ester of starch hydrolysate (3)").

[0060] (2) Preparation of an aqueous solution containing a sizing agent [Example 1] Room temperature water was added to the alkenyl succinate ester (1) of a starch hydrolysate to a dilution ratio of 20 times based on the weight of the alkenyl succinate ester of a starch hydrolysate, and the resulting diluted solution was stirred for a certain period of time to prepare an aqueous solution having a solids concentration of the alkenyl succinate ester (1) of a starch hydrolysate of 5.0 wt %.

[0061] Examples 2 and 3 An aqueous solution containing the alkenyl succinate ester of a starch hydrolysate (2) at a solids concentration of 5.0 wt % (Example 2) and an aqueous solution containing the alkenyl succinate ester of a starch hydrolysate (3) at a solids concentration of 5.0 wt % (Example 3) were prepared in the same manner as in Example 1, except that the alkenyl succinate ester of a starch hydrolysate (1) was replaced by the alkenyl succinate ester of a starch hydrolysate (2) or the alkenyl succinate ester of a starch hydrolysate (3).

[0062] [Comparative Example 1]

[0063] First, water was placed in a mixer. Then, wheat starch (Glyco Shiranami, manufactured by Matsumoto Yushi Pharmaceutical Co., Ltd.) and a silicone glidant (Silicon Star HS12, manufactured by Nissin Chemical Laboratory Co., Ltd.) were gradually added to the water in the mixer while thoroughly stirring to prevent the formation of aggregates, and the entire amount of each component was added. After confirming that the wheat starch had dissolved, wax (Maconol 88, manufactured by Matsumoto Yushi Pharmaceutical Co., Ltd.) was gradually added while thoroughly stirring, and the entire amount of wax was added, obtaining a mixed solution. The resulting mixed solution was heated at 92°C for 30 minutes and at 83°C for 10 minutes to dissolve and gelatinize the wheat starch components, preparing an aqueous starch paste solution (wheat starch content: 3.5 g / L, wax content: 2.5 g / L, silicone glidant content: 0.5 g / L).

[0064] (3) Apparatus and Reagents As a sizing machine, a Minisizer DCI001P (manufactured by Kaji Seisakusho Co., Ltd.) and an HGA-357 type sizing machine (manufactured in China, glue tank capacity approximately 47 L) were prepared.

[0065] (4) Operating Procedure [Example 1] 2500 mL of the aqueous solution of the alkenyl succinate ester (1) of the starch hydrolysate of Example 1 obtained in (2) above was placed in the above-mentioned sizing machine: Minisizer DC1001P. Furthermore, cotton yarn (1) (raw silk (unbleached yarn, spun yarn, etc.), 100% cotton, 20 count, single yarn, twist coefficient 4.5, average fiber length approximately 25 mm) manufactured by Izawa Towel Co., Ltd., fed from a cheese bobbin, was placed in the aqueous solution of the alkenyl succinate ester (1) of the starch hydrolysate in the sizing machine. Thereafter, the cotton yarn with the size solution (aqueous solution) adhered thereto was passed through a squeezing roll (first pass roll) under a pressure load of 0.04 MPa and an immersion roll (second pass roll) under a pressure load of 0.06 MPa, and further passed through a hot air drying section with a temperature of 110°C and a drying chamber length of approximately 3.8 m, and a cylinder roll drying section with a temperature of 110°C and eight cylinder rolls each having a diameter of 150 mm, at a speed of 15 m / min, thereby carrying out a sizing treatment. The weight of the cotton yarn (1) per unit length was measured for the cotton yarn (1) fed from the cheese bobbin (before sizing) and the cotton yarn (1) obtained as above after drying (after sizing).

[0066] Examples 2 and 3 Except for using 2500 mL of the aqueous solution of the alkenyl succinate ester (2) of the starch hydrolysate (Example 2) or 2500 mL of the aqueous solution of the alkenyl succinate ester (3) of the starch hydrolysate (Example 3) instead of 2500 mL of the aqueous solution of the alkenyl succinate ester (1) of the starch hydrolysate, sizing treatment was carried out in the same manner as the cotton yarn sizing treatment of Example 1. Then, for each of Examples 2 and 3, the weight per unit length of the cotton yarn (1) fed from the cheese bobbin and the weight per unit length of the resulting cotton yarn (1) after drying (after sizing) were measured in the same manner as in Example 1.

[0067] Comparative Example 1 35 L of the starch glue aqueous solution of Comparative Example 1 obtained in (2) above was placed into the above-mentioned sizing machine: HGA-357 type sizing machine. Furthermore, cotton yarn (1) (raw silk (unbleached yarn, spun yarn, etc.), 100% cotton, 20 count, single yarn, twist coefficient 4.5, average fiber length approximately 25 mm) manufactured by Izawa Towel Co., Ltd., fed from a cheese bobbin was placed into the starch glue aqueous solution in the sizing machine. The weight of the cotton yarn (1) per unit length fed from the cheese bobbin was measured. The cotton yarn with the attached size solution (aqueous solution) was then passed through a drying chamber of approximately 20 m and dried at 300°C. The excess size was then removed using a cylinder roll at approximately 120°C, and the resulting sized cotton yarn (1) was wound around a weaving beam. The cotton yarn passed through the drying chamber and cylinder roll at a speed of 30 m / min. The weight of the resulting dried (sized) cotton thread (1) per unit length was measured.

[0068] (5) Evaluation The following evaluations (5-1) to (5-3) were carried out for each of the sized yarns of Examples 1 to 3 and Comparative Example 1. The following evaluation (5-4) was also carried out for each of the sized yarns of Examples 1 and 2. In addition, the following evaluations (5-2) to (5-4) were carried out for the cotton yarn (1) before sizing. (5-1) Size Adhesion Rate (Amount of Adhesion) For each sized yarn, the size adhesion rate (amount of adhesion) (Sizing rate S) was calculated based on the following formula (1) using the weight (g) of the cotton yarn before sizing (weight before treatment) and the weight (g) of the cotton yarn after sizing (weight after treatment) in (4) above.

[0069]

[0070] (5-2) Abrasion Resistance (Number of Rubs) For each sized yarn, abrasion resistance was measured using a holding tester (1065, manufactured by Maeda Seisakusho) based on JIS L 1095:2010 (9.10 Abrasion Resistance Method B). Specifically, an abrasion test was conducted under the following test conditions, and the number of rubs until two out of 20 samples broke was measured. <Test Conditions> - Friction speed: 120 times / min - Friction angle: 110 degrees - Reciprocating distance: 2.5 cm - Test length: 20 cm - Friction element: hard steel wire with a diameter of 0.6 mm

[0071] (5-3) Single Yarn Tensile Strength and Elongation For each sized yarn, a tensile tester (Autograph AG-Xplus, manufactured by Shimadzu Corporation) was used to measure the single yarn tensile strength and elongation based on JIS L 1095:2010 (9.5 Single Yarn Tensile Strength and Elongation) under the conditions of a gripping distance of 20 cm and a pulling speed of 20 cm / min.

[0072] (5-4) Observation by Scanning Electron Microscope Using a tabletop microscope (Miniscope (registered trademark) TM4000Plus, manufactured by Hitachi High-Technologies Corporation) at an accelerating voltage of 15 kV, the surfaces of the cotton yarns before sizing used in Examples 1 to 3 and the cotton yarns after sizing in Examples 1 and 2 were observed.

[0073] The evaluation results of (5-1) to (5-3) above are shown in Table 1. The SEM observation results of (5-4) above for Examples 1 and 2 are shown in Figures 2 to 4. The correspondence between Figures 2 to 4 is as follows: Figure 2: SEM image of cotton yarn to which the sizing agent used in Examples 1 to 3 is not attached (magnification: 150x) Figure 3: SEM image of cotton yarn to which the alkenyl succinate ester (1) of the starch hydrolysate of Example 1 is attached (magnification: 150x) Figure 4: SEM image of cotton yarn to which the alkenyl succinate ester (2) of the starch hydrolysate of Example 2 is attached (magnification: 150x)

[0074]

[0075] The results in Table 1 show that the cotton yarns of Examples 1 to 3 (cotton yarns to which any of the alkenyl succinate esters (1) to (3) of starch hydrolysates has been attached) have improved performance in all of the number of frictions, single yarn tensile strength, and elongation compared to the cotton yarn (1) before sizing, and are excellent in abrasion resistance, single yarn tensile strength, and elongation. The cotton yarns of Examples 1 to 3 can be said to have similar performance in all of the number of frictions, single yarn tensile strength, and elongation to the cotton yarn to which starch glue has been attached of Comparative Example 1, and are therefore at a level that presents no practical problems as cotton yarns with sizing agents.

[0076] Furthermore, from the SEM photographs of Figures 3 and 4, it was found that when the alkenyl succinate ester (1) of the starch hydrolysate or the alkenyl succinate ester (2) of the starch hydrolysate was used as a sizing agent, fuzzing was suppressed and the entire surface was fixed with the sizing agent.

[0077] The results in Table 1 and Figures 2 to 4 demonstrate that the alkenyl succinate esters of starch hydrolysates of the present invention have excellent convergence properties. Furthermore, it was shown that any of the aqueous solutions containing the alkenyl succinate esters of starch hydrolysates (1), (2), or (3) can be used as a sizing agent, demonstrating that the alkenyl succinate esters of starch hydrolysates are useful as sizing agents regardless of their type.

[0078] 2. Desizing using supercritical carbon dioxide (1) Preparation of fabric or cotton yarn with sizing agent attached [Fabric with alkenyl succinate ester (1) of starch hydrolysate attached] Cotton yarn (1) (Example 1, size deposition rate: 5.2 wt% (Table 1)) (No. 20 single yarn) (used as pile yarn) and cotton yarn (TS cotton yarn, manufactured by KB Tsuzuki Co., Ltd., No. 30 two-ply yarn) were used as warp yarns, and cotton yarn (TS cotton yarn, manufactured by KB Tsuzuki Co., Ltd., No. 20 single yarn) was used as weft yarns. A woven fabric (warp density: 40 threads / inch, weft density: 45 threads / inch; in the fabric, the size-deposited cotton yarn (1): approximately 30%, the TS cotton yarn in the warp: approximately 30%, and the TS cotton yarn in the weft: approximately 40%) was woven on a loom (Itema loom, manufactured in Italy). The size deposition rate of the entire woven fabric was calculated to be 1.6 wt%. The appearance of the resulting woven fabric is shown in Figure 5.

[0079] [Starch-adhered cotton yarn] A sized cotton yarn (1) was obtained and wound around a weaving beam in the same manner as in [Comparative Example 1] in 1.(4) above, except that various operating conditions such as the drying temperature, the amount of size removed by the cylinder roll, and the cotton yarn passing speed were adjusted so that the adhesion rate (adhesion amount) of the size agent (starch) in the finally obtained sized yarn would be 3.8% by weight.

[0080] (2) Apparatus and Reagents The overall apparatus used in the treatment with a fluid containing supercritical carbon dioxide is shown in Figure 6. The reference numerals in Figure 6 represent: 1: chiller unit; 2: CO ２ Supply pump, 3: Air vent valve, 4: Check valve, 5: Pressure transmitter, 6: Safety valve, 7: Dyeing vessel, 8: Vessel drain valve, 9: Vessel temperature sensor, 10: Magnetic induction type agitator, 11: Exhaust flow rate adjustment valve, 12: Vessel exhaust valve, 13: Control panel, 14: CO ２ Outlet for supply pump, 15: Outlet for dyeing vessel heater, A: CO ２ The chiller unit 1 is a cooling water circulation device LTC-450α (manufactured by AS ONE Corporation), CO ２ A double plunger pump NP-KX-500 (manufactured by Nippon Seimitsu Kagaku Co., Ltd.) was used as the supply pump 2, and a high-pressure vessel (manufactured by ITEC Co., Ltd., model: C-04-M-FU, capacity: 400 mL) was used as the dyeing vessel 7. A liquefied carbon dioxide cylinder (Kind Gas Co., Ltd., purity 99.5% or higher) was used as the carbon dioxide supply source.

[0081] (3) Operating Procedure (3-1) Fabric with Sizing Agent Adhered (3-1-1) Use of Water as a Co-Solvent A jig (110 cm long x 15 mm outer diameter, hollow cylindrical, mesh structure, made of metal) was prepared, and the woven fabric (approximately 9 cm x approximately 21 cm, approximately 10 g) of the example fabric obtained in 2. (1) [Fabric with Alkenyl Succinate Ester (1) of Starch Hydrolysate Adhered] above (using cotton yarn (1) with starch hydrolysate alkenyl succinate ester (1) glued to the warp) obtained in 2. (1) [Fabric with Alkenyl Succinate Ester (1) of Starch Hydrolysate Adhered] was wrapped around the jig. A cotton string was further wrapped around the wrapped fabric to secure it in place. An outer cylinder (110 cm long, 36 mm inner diameter, 41 mm outer diameter) was also prepared, and a paper wiper (Kimwipes®, 120 mm x 210 mm) evenly impregnated with 2 mL of water, the co-solvent, was wrapped around the outside of the outer cylinder. A cotton string was further wrapped around the wrapped paper wiper to secure it in place. The jig with the fabric wrapped around it was placed and fixed inside the outer cylinder with the paper wiper wrapped around it, and a measurement sample was obtained. The obtained measurement sample was placed in the dyeing container 7. Next, CO ２ Using the supply pump 2, 200 mL of carbon dioxide was delivered to the dyeing vessel 7 at a delivery rate of 20 to 300 mL / min, pressurizing the dyeing vessel 7. The conditions for treating the measurement sample with supercritical carbon dioxide fluid were 120°C, 25 MPa, 180 minutes, batchwise. Agitation was performed using a propeller, with one set consisting of 60 seconds of forward rotation and 60 seconds of reverse rotation, and this set was repeated at 900 rpm for 180 minutes. The water soaked into the paper wiper became mixed with supercritical carbon dioxide, resulting in a supercritical carbon dioxide:fabric volume ratio of 40:1 and a supercritical carbon dioxide:water volume ratio of 200:1. After treatment with supercritical carbon dioxide fluid, the valve for the dyeing vessel 7 was opened and the pressure was released to atmospheric pressure. After releasing the pressure in the dyeing vessel 7, the fabric was removed from the jig and dried at 105°C for 2 hours. The dried fabric was weighed.

[0082] (3-1-2) Use of EGME as a co-solvent A measurement sample was prepared in the same manner as in (3-1-1) above, except that 5 mL of EGME (ethylene glycol monobutyl ether) was used instead of 2 mL of water as the co-solvent to be impregnated into the paper wiper, and the measurement sample was treated with supercritical carbon dioxide fluid. The fabric was then removed from the jig, dried, and weighed. The EGME impregnated into the paper wiper was mixed with supercritical carbon dioxide, resulting in a supercritical carbon dioxide:fabric volume ratio of 40:1 and a supercritical carbon dioxide:EGME volume ratio of 80:1.

[0083] (3-2) Cotton yarn having alkenyl succinate ester (1) of starch hydrolysate attached thereto (3-2-1) Use of 1 mL of water as co-solvent Instead of wrapping the woven fabric of the Example obtained in 2.(1) above [Fabric having alkenyl succinate ester (1) of starch hydrolysate attached thereto] around the jig, cotton yarn (1) (Example 1, sizing rate: 5.2 wt% (Table 1)) (length: approximately 400 m, approximately 10 g) having been sizing with alkenyl succinate ester (1) of starch hydrolysate prepared in 1.(4) above was wrapped around the jig, and a measurement sample was prepared and treated with supercritical carbon dioxide fluid in the same manner as in (3-1-1) above, except that the amount of water as a co-solvent impregnated into the paper wiper was changed from 2 mL to 1 mL. The cotton yarn was then removed from the jig, dried, and then weighed. The water soaked into the paper wiper is mixed with supercritical carbon dioxide, and the volume ratio of supercritical carbon dioxide to cotton thread is 40:1, and the volume ratio of supercritical carbon dioxide to water is 400:1.

[0084] (3-2-2) 2 mL of water was used as the co-solvent, and the treatment time was 360 minutes. A measurement sample was prepared and treated with supercritical carbon dioxide fluid in the same manner as in (3-2-1) above, except that the amount of water as the co-solvent impregnated into the paper wiper was changed from 1 mL to 2 mL, and the treatment time with supercritical carbon dioxide fluid was changed from 180 minutes to 360 minutes. The cotton yarn was then removed from the jig, dried, and weighed. The water impregnated into the paper wiper was mixed with supercritical carbon dioxide, resulting in a supercritical carbon dioxide:cotton yarn volume ratio of 40:1 and a supercritical carbon dioxide:water volume ratio of 200:1.

[0085] (3-3) Cotton yarn having alkenyl succinate ester (2) of starch hydrolysate attached thereto A measurement sample was prepared and treated with supercritical carbon dioxide fluid in the same manner as in (3-1-1) above, except that cotton yarn (1) (Example 2, sizing rate: 7.1 wt % (Table 1)) (length: approximately 400 m, approximately 10 g) having been sizing with alkenyl succinate ester (2) of starch hydrolysate prepared in (4) above was wound around the jig instead of the woven fabric of the Example obtained in (1) above in 2. [Fabric having alkenyl succinate ester (1) of starch hydrolysate attached thereto]. The water soaked into the paper wiper is mixed with supercritical carbon dioxide, and the volume ratio of supercritical carbon dioxide to cotton thread is 40:1, and the volume ratio of supercritical carbon dioxide to water is 200:1.

[0086] (3-4) Cotton yarn having alkenyl succinate ester (3) of starch hydrolysate attached thereto A measurement sample was prepared and treated with supercritical carbon dioxide fluid in the same manner as in (3-1-1) above, except that cotton yarn (1) (Example 3, sizing rate: 2.9 wt% (Table 1)) (length: approximately 400 m, approximately 10 g) having been sizing with alkenyl succinate ester (3) of starch hydrolysate prepared in (4) above, was wound around the jig instead of the woven fabric of the Example obtained in (1) above in 2. [Fabric having alkenyl succinate ester (1) of starch hydrolysate attached thereto]. The cotton yarn was then removed from the jig, dried, and then weighed. The water soaked into the paper wiper is mixed with supercritical carbon dioxide, and the volume ratio of supercritical carbon dioxide to cotton thread is 40:1, and the volume ratio of supercritical carbon dioxide to water is 200:1.

[0087] (3-5) Starch-sizing cotton yarn. Instead of wrapping the woven fabric of Example 1 obtained in 2.(1) above around the jig, cotton yarn (1) (corresponding to a comparative example, starch-sizing rate: 3.8 wt%) (length: approximately 400 m, approximately 10 g) prepared in 2.(1) [Starch-sizing cotton yarn] above was wrapped around the jig. A measurement sample was prepared and treated with supercritical carbon dioxide fluid in the same manner as in (3-1-1) above. The cotton yarn was then removed from the jig, dried, and weighed. The water soaked into the paper wiper was mixed with supercritical carbon dioxide, resulting in a supercritical carbon dioxide:cotton yarn volume ratio of 45:1 and a supercritical carbon dioxide:water volume ratio of 200:1.

[0088] (4) Evaluation The evaluation results for the following items (4-1) and (4-2) are shown in Table 2. The sample numbers in Table 2 correspond to the above-mentioned items (3-1-1) to (3-5), respectively. (4-1) Size Removal Rate The size removal rate (Desizing rate D) was calculated based on the following formula (2) using the size adhesion rate (%) of the sized fabric or cotton yarn (fabric or cotton yarn after sizing treatment and before desizing treatment) (sized fabric: 1.6 wt% as described above, sized cotton yarn: 5.2, 7.1, 2.9, or 3.8 wt% as described above) and the size adhesion rate (%) of the fabric or cotton yarn after the above-mentioned desizing treatment.

[0089]

[0090] (4-2) Solubility of Sizing Agent in Supercritical Carbon Dioxide Fluid The solubility (g / mL) of the sizing agent (alkenyl succinate ester (1) or starch paste) in supercritical carbon dioxide fluid (total of supercritical carbon dioxide and cosolvent) was calculated based on the following formula (3).

[0091]

[0092]

[0093] The results for Samples 3-1-1 and 3-1-2, which treated the woven fabrics in Table 2, demonstrate that desizing with supercritical carbon dioxide can sufficiently remove alkenyl succinate esters, which are starch hydrolysates, from fabrics. Furthermore, the rate of sizing removal did not change between the case where the co-solvent was 2 mL of water (Sample 3-1-1) and the case where the co-solvent was 5 mL of EGME (Sample 3-1-2). Based on these results, the use of 2 mL of water as a co-solvent, which requires less addition, is considered to be a more effective formulation.

[0094] The results of Samples 3-2-1 and 3-2-2 in Table 2, which were cotton yarn samples, show that alkenyl succinate esters, which are starch hydrolysates, can be sufficiently removed from yarn by desizing with supercritical carbon dioxide. It was also found that the removal rate of sizing agent increased by increasing the amount of co-solvent used and by extending the treatment time with supercritical carbon dioxide fluid.

[0095] Samples 3-1-1 and 3-1-2, which were treated with woven fabric, had a higher rate of sizing agent removal than samples 3-2-1 and 3-2-2, which were treated with yarn. Without being bound by theory, it is presumed that this is because the winding conditions around the jig differed between the woven fabric and the yarn, making the woven fabric more susceptible to contact with the supercritical carbon dioxide fluid.

[0096] A comparison of the results for Samples 3-2-1 and 3-2-2 with those for Samples 3-3 and 3-4, which used different types of alkenyl succinate esters of starch hydrolysates, revealed that even when the type of alkenyl succinate ester was changed, the alkenyl succinate esters of starch hydrolysates could be sufficiently removed by desizing using supercritical carbon dioxide. Furthermore, Sample 3-4, which used alkenyl succinate ester (3) of starch hydrolysates, exhibited a particularly high rate of sizing agent removal. Without being bound by theory, it can be inferred that the higher hydrophobicity of the alkenyl group in alkenyl succinate ester (3) of starch hydrolysates resulted in increased hydrophobicity of alkenyl succinate ester (3) of starch hydrolysates, making desizing using supercritical carbon dioxide fluid easier. In addition, the removal rate of the sizing agent in sample number 3-4 exceeded 100%, which is thought to be because components other than the sizing agent originally contained in the cotton yarn were removed in the desizing process.

[0097] The results of sample number 3-5 (comparative example) in Table 2, which was a cotton yarn treated with starch paste, showed that the starch paste could not be sufficiently removed by desizing using supercritical carbon dioxide. A comparison of sample numbers 3-2-1, 3-2-2, 3-3, and 3-4 in Table 2 with sample number 3-5 (comparative example) showed that the desizing using supercritical carbon dioxide showed a much higher removal rate of alkenyl succinate esters, starch hydrolysates, than starch paste.

[0098] From the above, it was found that the sizing agent-coated textile product according to one aspect of the present invention is suitable for desizing using supercritical carbon dioxide. Furthermore, from the above results, it was found that the sizing agent-coated textile product of this embodiment is not only suitable for desizing using supercritical carbon dioxide, but also has high durability against friction, or can exhibit high tensile strength, or can exhibit high tensile elongation.

[0099] 1: Chiller unit 2: CO ２Supply pump 3: Air vent valve 4: Check valve 5: Pressure transmitter 6: Safety valve 7: Dyeing vessel 8: Vessel drain valve 9: Vessel temperature sensor 10: Magnetic induction stirrer 11: Exhaust flow rate adjustment valve 12: Vessel exhaust valve 13: Control panel 14: CO ２ Outlet for supply pump 15: Outlet for dyeing vessel heater A: CO ２ cylinder

Claims

1. A sizing textile product, wherein the sizing agent contains an alkenyl succinate ester of a starch hydrolysate.

2. The sizing textile product according to claim 1, wherein the alkenyl succinate ester of a starch hydrolysate comprises octenyl succinate ester of dextrin, octenyl succinate ester of maltose, dodecenyl succinate ester of maltose, or a combination thereof.

3. The sizing textile product according to claim 1 or 2, wherein the alkenyl succinic acid content in the alkenyl succinic acid ester of the starch hydrolysate is 5 to 50% by weight.

4. The sizing textile product according to claim 1 or 2, wherein the DE of the starch hydrolysate, which is a constituent of the alkenyl succinate ester of the starch hydrolysate, is 5 to 80.

5. The sized textile product according to claim 1 or 2, wherein the textile product comprises cotton yarn or cotton fabric.

6. The sized textile product according to claim 1 or 2, wherein the adhesion rate of the sizing agent to the sized textile product is 0.1 to 10% by weight.

7. A sizing agent containing an alkenyl succinic acid ester of a starch hydrolysate for producing the sizing textile product according to claim 1 or 2.

8. A method for producing a sizing agent-coated textile product according to claim 1 or 2, comprising the step of bringing a fluid containing the sizing agent into contact with the textile product to size the textile product.

9. A method for producing textile products from sized textile products according to claim 1 or 2, comprising the step of contacting the sized textile product with a fluid containing supercritical carbon dioxide to desize the sized textile product.

10. The method of claim 9, wherein the desizing step is a batch or continuous process.

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