Water-soluble male-shaped hook and loop fastener and its manufacturing method

Abstract

The present invention provides a water-soluble male-shaped hook and loop fastener, which has a substrate and a plurality of male-shaped hook elements protruding from the surface of the substrate, and satisfies (1) to (3). (1) The plurality of male-shaped hook elements are arranged in a row, each hook element has a shape of rising from the substrate surface, bending in the column direction from the middle, and the front end portion is facing the direction close to the substrate surface, or each hook element has a shape of rising from the substrate surface, branching in the front and back directions in the middle of the column direction and bending in the column direction, and the front end portions of the branches are facing the direction close to the substrate surface; (2) The substrate and the male-shaped hook elements are both formed by a mixture of polyvinyl alcohol, polyol or ethylene oxide polymer, and layered inorganic particles, with 5 to 30 parts by mass of the polyol or ethylene oxide polymer and 3 to 20 parts by mass of the layered inorganic particles relative to 100 parts by mass of polyvinyl alcohol; (3) The degree of polymerization of the polyvinyl alcohol is 300 to 700, and the degree of saponification is 60 to 80 mol%.

Description

Technical Field

[0001] The present invention relates to a water-soluble male-shaped hook and loop fastener having a male-shaped hook element on the surface, a method for manufacturing the same, and a combination of the water-soluble male-shaped hook and loop fastener capable of hooking. Specifically, the present invention relates to a water-soluble male-shaped hook and loop fastener capable of hooking, a water-soluble male-shaped hook and loop fastener capable of hooking, the water-soluble male-shaped hook and loop fastener being a water-soluble male-shaped hook that rapidly dissolves in water at room temperature to eliminate the hooking force, the male-shaped hook element being soft, the hook element not being broken, the substrate not being cracked, having a high hook force, and suppressing the stickiness of the surface. Background Art

[0002] For a long time, the following method has been used as one of the methods for mounting an object on the surface of an object: a male Velcro having hook-type or mushroom-type male hooking elements is mounted on the surface of either the object or the object, and a loop Velcro having loop hooking elements is mounted on the surface of the other object, and then the hooking element surfaces of the two Velcros are overlapped to hook the two hooking elements, thereby fixing the object to the surface of the object. Since it can be loaded and unloaded multiple times by repeatedly hooking / peeling off, and can be peeled off and easily adjusted in the event that the installation position is incorrect, etc., it has received attention as a mounting method.

[0003] In recent years, such hook and loop fasteners have been used to fix sanitary products to underwear or to fix disposable diapers at the waist. If the hook and loop fasteners are water-soluble, the sanitary products and disposable diapers can be directly flushed into a flush toilet after use by making the sanitary products and disposable diapers water-degradable non-woven fabrics. In addition, there are also uses in which the connection state based on the hook and loop fasteners disappears by putting the objects bound by the hook and loop fasteners into water, and the objects are unfolded in the water or on the water surface for use. If the hook and loop fasteners used for such uses can dissolve quickly when in contact with water, it is expected that the scope of use will be further expanded.

[0004] In addition, if the male fastener and the loop fastener that constitute the fastener are both water-soluble, the speed of dissolving in water and causing the hooking force to disappear can be further increased. Moreover, if the resin that constitutes such a fastener is a resin that biodegrades after dissolution, it is also environmentally friendly and meets social needs.

[0005] Due to such expectation, as a hook and loop fastener, a fast water dissolution speed is required. Among hook and loop fasteners, a loop hook and loop fastener having a loop hook element can be easily obtained by using a water-decomposable nonwoven fabric having loop fibers on the surface. However, it is difficult to obtain a male hook and loop fastener having a male hook element that dissolves rapidly in normal temperature water and has sufficient hooking force. At present, there is no commercially available water-soluble male hook and loop fastener that meets the expectation. In addition, there is no commercially available product for a loop hook and loop fastener formed of water-soluble fibers whose hooking force disappears more rapidly than that of a water-decomposable nonwoven fabric.

[0006] However, attempts have been made to obtain water-soluble male hook and loop fasteners. For example, Patent Document 1 describes a molded male hook and loop fastener made of a water-soluble resin such as water-soluble polyvinyl alcohol as a water-soluble male hook and loop fastener. However, the document does not describe a specific water-soluble polyvinyl alcohol.

[0007] Resins such as polyvinyl alcohol have the advantage of being able to obtain fibers with excellent physical properties such as strength by wet spinning and dry spinning, but on the contrary, there are the following major problems: in the case of melt molding, the decomposition temperature and melting temperature of polyvinyl alcohol are very close, and even if the polyvinyl alcohol is heated only to melt it, it will decompose and gel before melting, and melt molding cannot be performed, and the desired molded product cannot be obtained. In particular, in the case of a small molded product such as a male hook element, the problem of decomposition and gelation is serious, and even if a film layer of the base body is obtained, it is difficult to obtain a male molded hook and loop fastener on the surface of which a large number of male hook elements are not broken in the middle and extend to the front end without breaking.

[0008] In addition, in patent documentation 2, as the water-soluble molding hook and loop fastener that can be suitably used for disposable products, it is recorded that the use of the copolymer of polyoxyalkylene and vinyl alcohol and allyl alcohol is carried out graft polymerization and the water-soluble resin obtained. However, such complicated copolymerization water-soluble resin is not yet commercially available, and it is impossible to easily obtain, in addition, when using a resin similar to this complicated copolymerization resin to manufacture the male molding hook and loop fastener, it may not be possible to satisfy the moldability, in the case of thin male hooking element, it is difficult to obtain the hooking element extending to its front end, and the hardness of the molding obtained is high, and the hooking element is easily broken when small, in addition, the surface of the male molding hook and loop fastener obtained is easily sticky, and it is difficult to use. In fact, the water-soluble male molding hook and loop fastener formed by resin as recorded in patent documentation 2 is not yet manufactured, sold.

[0009] In addition, in the above-mentioned patent document 1, as a water-soluble male hook and loop fastener, a fabric hook and loop fastener formed of water-soluble fibers is also described, but in the case of the fabric hook and loop fastener, the male hook element has a loop shape formed of a monofilament, and in the case of a monofilament formed of water-soluble polyvinyl alcohol, the heat setting property is poor, and as a result, the loop shape is easily extended by a light hook, so that the hook is released and sufficient hooking force cannot be obtained. If polyvinyl alcohol with high heat setting property is used to prevent the above situation, the obtained hook and loop fastener is difficult to dissolve in water at room temperature.

[0010] Prior art literature

[0011] Patent Literature

[0012] Patent Document 1: Japanese Patent Application Publication No. 2006-325939

[0013] Patent Document 2: Japanese Patent Application Laid-Open No. 09-313218 Summary of the invention

[0014] Problems to be solved by the invention

[0015] The object of the present invention is to provide a water-soluble male type molded hook and loop fastener and a method for making the same, and to provide a combination of the water-soluble male type molded hook and loop fastener that can be hooked, wherein the male type molded hook quickly dissolves in normal temperature water, wherein the male type hook element is soft, and the resin used in the molding can be suppressed from gelling and decomposing during molding, and as a result, the male type hook element is basically not broken, the matrix layer is cracked, etc., and the hook force is high, and the surface is also suppressed from being sticky. In addition, it is preferred that the object of the present invention is to provide a water-soluble male type molded hook even with a small male type hook element with poor moldability, and the above-mentioned performance is not substantially deteriorated.

[0016] Solutions to the problem

[0017] That is, the present invention is a water-soluble male-type molded hook and loop fastener having a base and a plurality of male-type hook elements protruding from the surface of the base, and satisfying the following (1) to (3).

[0018] (1) A plurality of male hook elements are arranged in a row, each hook element having a shape of standing up from the substrate surface, bending in the middle of the hook element in the row direction, and having its front end facing a direction close to the substrate surface; or each hook element having a shape of standing up from the substrate surface, branching in the middle of the hook element in the row direction, and bending in the row direction, and having each front end of the branch facing a direction close to the substrate surface;

[0019] (2) The base and the male hook element are both formed of a mixture of polyvinyl alcohol, a polyol or an ethylene oxide polymer, and layered inorganic particles, wherein the mixing ratio is 5 to 30 parts by weight of the polyol or the ethylene oxide polymer, and 3 to 20 parts by weight of the layered inorganic particles relative to 100 parts by weight of the polyvinyl alcohol;

[0020] (3) The degree of polymerization of the polyvinyl alcohol is 300 to 700, and the degree of saponification is 60 to 80 mol %.

[0021] In addition, the following situation is preferred: in such a water-soluble male molded hook and loop fastener, when the male hook element has a shape that stands up from the base surface, bends in the column direction from the middle, and its front end portion is facing in the direction close to the base surface, the height from the base surface of the male hook element to the top of the male hook element is 1.2 mm or less; when the male hook element has a shape that branches front and rear in the middle of the column direction and bends respectively in the column direction, and each front end of the branch is facing in the direction close to the base surface, the height from the base surface of the male hook element to the top of the male hook element is 0.6 mm or less.

[0022] In addition, the following situations are preferred: in the above-mentioned water-soluble male-type molded fastener, sometimes the polyol or ethylene oxide polymer is polyethylene glycol, and its number average molecular weight is 300 to 700; in addition, sometimes the layered inorganic particles are talc; in addition, sometimes the above-mentioned water-soluble male-type molded fastener has water-solubility that allows it to be completely dissolved in water at 25°C within 20 minutes; in addition, sometimes more than 98% of the male-type hook elements have a front end portion that is not interrupted in the middle and is facing in a direction close to the surface of the substrate.

[0023] In addition, the present invention is a combination of the above-mentioned water-soluble male-type molded fastener and a water-soluble loop fastener formed by water-soluble fibers, and the following situation is preferred: in such a combination, the water-soluble loop fastener is a non-woven fabric formed by polyvinyl alcohol fibers, and loops formed by the fibers exist on its surface.

[0024] In addition, the present invention is a method for manufacturing a water-soluble male-shaped hook and loop fastener, the method comprising: flowing a molten mixture satisfying the following (4) and (5) over the surface of a metal roller satisfying the following (A), and simultaneously pressing the molten mixture into a cavity in the shape of a male-shaped hook element perforated on the surface of the metal roller, cooling and solidifying the molten mixture in this state, peeling the mixture from the surface of the metal roller, and extracting the mixture from the cavity,

[0025] (A) The metal roller is formed by stacking a thin annular mold having a plurality of cavities in the shape of male hook elements carved on the outer circumference, wherein the plurality of cavities for male hook elements are arranged in a row in the circumferential direction of the roller on the surface of the metal roller, each cavity is bent in the row direction of the cavity midway and its front end is close to the surface of the metal roller, or each cavity is branched into two branches midway and each branch is bent in the row direction and its front end is close to the surface of the metal roller;

[0026] (4) a mixture of polyvinyl alcohol, a polyol or an ethylene oxide polymer, and layered inorganic particles, wherein the mixing ratio is 5 to 30 parts by weight of the polyol or the ethylene oxide polymer, and 3 to 20 parts by weight of the layered inorganic particles relative to 100 parts by weight of the polyvinyl alcohol;

[0027] (5) The degree of polymerization of the polyvinyl alcohol is 300 to 700, and the degree of saponification is 60 to 80 mol %.

[0028] In addition, it is preferred that in such a method for manufacturing a water-soluble male-type molded hook and loop fastener, when the cavity has a shape that is bent in the row direction of the cavity midway and its front end is close to the surface of the metal roller, the depth of the cavity from the surface of the metal roller is 1.2 mm or less at the deepest point, or

[0029] When the cavity has a shape in which two branches are branched in the middle and each branch is bent in the column direction and the tip end is close to the metal roller surface, the depth of the cavity from the metal roller surface is 0.6 mm or less at the deepest point.

[0030] Effects of the Invention

[0031] In the present invention, the resin composition for molding comprises special polyvinyl alcohol, polyol or ethylene oxide polymer and layered inorganic particles, and they are mixed together with a specific amount ratio. By using such special resin composition, a water-soluble male molding hook and loop fastener that can be dissolved rapidly in normal temperature water can be obtained. Moreover, such special resin composition will not gel or decompose substantially under melt molding conditions, and then has excellent moldability, as a result, the male hooking element will not be broken substantially in molding, cracks will be generated in the matrix layer, etc. In addition, the male molding hook and loop fastener obtained is soft, and from this point of view, the male hooking element will not be broken, the cracks in the matrix layer will not be easily generated. In addition, for the molding hook and loop fastener obtained in the present invention, the layered inorganic particles added can improve moldability, and can suppress the stickiness of the hook and loop fastener surface, even in an environment with high humidity, it can be used without problems.

[0032] Moreover, the male-type molded hook and loop fastener of the present invention utilizes the following method: the melt of the above-mentioned special resin composition flows over the surface of the metal roller as described above, and the melt is pressed into a cavity in the shape of a male-type hooking element formed by perforating holes arranged in rows on the surface of the metal roller. In this state, the melt is cooled and solidified, then peeled off from the surface of the metal roller, and extracted from the cavity. As a result, for the obtained water-soluble male-type molded hook and loop fastener, multiple male-type hooking elements are arranged in rows, each hooking element has a shape that stands up from the substrate surface, bends from the middle of the row direction, and its front end is facing the direction close to the substrate surface (hereinafter, this shape is sometimes referred to as an inverted J-shape), or each hooking element has a shape that stands up from the substrate surface, branches front and back in the middle of the row direction and bends along the row direction, and each front end of the branch faces the direction close to the substrate surface (hereinafter, this shape is sometimes referred to as a Y-shape).

[0033] The bending direction of such male hook elements is unified, and they work together to resist the stretching in the hook element row direction from the hook object, so they are not easy to break, and it is easy to obtain a higher hook force compared with other male molded hook and loop fasteners where the hook element head (hook expansion head) extends in a direction intersecting the hook element row, the front end of the rod is spread out in an umbrella shape, etc. In particular, in the present invention, when the height of the male hook element is low, combined with the softness of the male hook element, even if it is installed in a part that is easy to contact the skin like a sanitary product, the foreign body sensation can be suppressed, and even if it contacts the skin, it is not easy to cause skin roughness, and the time required for dissolution can be further shortened.

[0034] In addition, the polyvinyl alcohol, polyol or ethylene oxide polymers, and layered inorganic particles that constitute the water-soluble male-type molded fastener of the present invention are all used in large quantities for contact with human skin. Therefore, the water-soluble male-type molded fastener of the present invention is not easy to cause harm to the human body. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 This is a perspective view of an example of the water-soluble male-type molded hook and loop fastener of the present invention.

[0036] Figure 2 It is a perspective view of another example of the water-soluble male type molded hook and loop fastener of the present invention.

[0037] Figure 3 This is a photograph as an alternative to a drawing showing the surface of an example of the water-soluble male-type molded surface fastener of the present invention.

[0038] Explanation of symbols

[0039] 1: Male hook element

[0040] 2: Matrix

[0041] T: row direction of male hook elements DETAILED DESCRIPTION

[0042] Next, the water-soluble male-type molded hook and loop fastener of the present invention and the method for producing the same are described in detail. First, as described above, the water-soluble male-type molded hook and loop fastener of the present invention is formed of a special polyvinyl alcohol resin, a polyol or ethylene oxide polymer, and layered inorganic particles.

[0043] Among them, the degree of polymerization of polyvinyl alcohol (hereinafter referred to as PVA), that is, the viscosity-average degree of polymerization (hereinafter simply recorded as the degree of polymerization), must be in the range of 300 to 700. When the degree of polymerization is less than 300, the strength of the male hook element of the obtained male molded hook and loop fastener is reduced. On the contrary, when the degree of polymerization exceeds 700, the melt viscosity becomes high, the moldability is reduced, gelation is easily caused, and the molten resin cannot reach the front end of the cavity. As a result, it is difficult to obtain a male molded hook and loop fastener with a male hook element extending to the front end. In particular, when the male hook element is a thin shape, the impact of reduced moldability becomes clear. The degree of polymerization is preferably in the range of 350 to 600, and more preferably in the range of 370 to 550.

[0044] The degree of polymerization (viscosity average degree of polymerization) is a value measured in accordance with JIS K 6726: 1994. Specifically, when the degree of saponification is less than 99.5 mol%, the viscosity average degree of polymerization (P) is determined by the following formula using the limiting viscosity [η] (L / g) measured in water at 30°C for PVA saponified to a saponification degree of 99.5 mol% or more.

[0045] P = ([η] × 104 / 8.29)(1 / 0.62)

[0046] In addition, the saponification degree of PVA must be in the range of 60 to 80 mol%. When the saponification degree is less than 60 mol%, it becomes too soft and cannot obtain the strength / elastic modulus required for the male hook element of the Velcro, and the hooking force cannot be obtained. This becomes particularly obvious when the male hook element is in a thin shape. On the contrary, when the saponification degree exceeds 80 mol%, the water solubility is poor and it cannot be dissolved quickly. In addition, the moldability is reduced, gelation is likely to occur, and the molten resin cannot reach the end of the cavity, making it difficult to obtain a male molded Velcro with a male hook element extending to the front end. In particular, when the male hook element is in a thin shape, gelation becomes obvious. The saponification degree is preferably in the range of 70 to 80 mol%, and more preferably in the range of 72 to 78 mol%.

[0047] The saponification degree is a value measured based on JIS K6726:1994.

[0048] There are no particular restrictions on the preparation method of such PVA. It is generally prepared by hydrolysis or alcoholysis of polyvinyl acetate. In the present invention, a saponified product of a homopolymer of vinyl acetate is sometimes preferred. Of course, within the range of not seriously damaging the water solubility and formability of PVA, a small amount of other vinyl monomers such as vinyl formate, vinyl acetate, vinyl propionate, vinyl versatate, vinyl pivalate, and other α-olefins can be copolymerized, and a polymer obtained by modifying the terminal of the polymer can also be used. In addition, as a polymerization method for polyvinyl acetate, solution polymerization, bulk polymerization, bead polymerization, emulsion polymerization, etc. can be cited.

[0049] Next, the polyol or ethylene oxide-based polymer used as a raw material constituting the water-soluble male-type molded surface fastener of the present invention will be described.

[0050] As the polyol, aliphatic alcohols having a valence of 3 or more can be cited, and specific examples thereof include glycerol, pentaerythritol, sorbitol, etc., to which alkylene oxides such as ethylene oxide and propylene oxide can be added. Among them, those obtained by adding 2 to 10 moles of ethylene oxide to glycerol and sorbitol are preferred because of their high plasticizing effect on PVA.

[0051] In addition, as a specific example of an ethylene oxide polymer, polyethylene glycol can be cited. In particular, from the perspective of being less likely to seep out, and from the perspective of less gasification when forming a hook and loop fastener and not causing a deterioration in the workplace environment, among the above-mentioned polyols or ethylene oxide polymers, polyethylene glycol is the most preferred low polymer with a number average molecular weight of 300 to 700.

[0052] By using such a polyethylene glycol with a low number average molecular weight, the moldability of PVA can be improved, and the obtained male-shaped molded hook and loop fastener can be made soft. On the other hand, when the number average molecular weight is 300 or more, the polyethylene glycol is not easy to ooze out on the surface of the obtained male-shaped molded hook and loop fastener, and the surface is not easy to be sticky. In addition, when it is 700 or less, the moldability is more excellent. More preferably, the polyethylene glycol has a number average molecular weight in the range of 350 to 500, and particularly preferably in the range of 370 to 450.

[0053] Polyethylene glycol may be copolymerized with a small amount of an alkylene oxide, such as propylene oxide.

[0054] The number average molecular weight of the polyethylene glycols in the present invention is the value measured as described below. In a stoppered flask, add 1 g of the polyethylene glycol sample of the object to be measured (weighed to the digit of 0.1 mg) to 25 mL of accurately weighed phthalic anhydride pyridine solution, plug the stopper, heat in a boiling water bath for 2 hours, and place until it reaches room temperature. Then, add 50 mL of 0.5 mol / L sodium hydroxide aqueous solution (accurately weighed) and 10 drops of phenolphthalein solution for titration to the flask. Use 0.5 mol / L sodium hydroxide aqueous solution to titrate the liquid in the flask, and the moment when the liquid remains red for 15 seconds is taken as the end point. Based on the titration M (mL) of this test obtained in this way, and the titration R (mL) obtained by performing a blank test in the same manner as above except that no polyethylene glycol sample is used, the number average molecular weight = {(collection amount of polyethylene glycol sample (g)) × 4000} / {(MR) × 0.5 (mol / L)} is calculated.

[0055] The amount of such polyol or ethylene oxide addition polymer (sometimes these compounds are also representatively referred to as polyethylene glycols) added is in the range of 5 to 30 parts by mass relative to 100 parts by mass of PVA. When the amount is less than 5 parts by mass, the effect of adding polyethylene glycol, i.e., the improvement of moldability and the softness of the molded product cannot be obtained. When the amount exceeds 30 parts by mass, polyethylene glycol oozes out on the surface of the obtained male molded hook and loop fastener, the surface becomes sticky, and the male hook element of the obtained male molded hook and loop fastener does not have sufficient strength. The range is preferably 7 to 25 parts by mass, and particularly preferably 8 to 23 parts by mass.

[0056] In addition, layered inorganic particles are added to the raw materials constituting the water-soluble male-shaped hook and loop fastener of the present invention. The layered inorganic particles can reduce the stickiness of the surface of the obtained male-shaped hook and loop fastener. In addition, since the layers are arranged in parallel with the flow direction of the resin during molding, the fluidity of the molten liquid will not be seriously damaged despite the addition of solid matter, and excellent strength can be given to the obtained molded product.

[0057] Moreover, in the case of manufacturing the male hook element by pressing the resin melt into the cavity of the male hook element shape perforated on the surface of the metal roller and then cooling and solidifying the melt in this state and then peeling it off from the surface of the metal roller, the layer of the layered inorganic particles added to the molten resin is arranged in parallel with the flow direction of the molten resin, and as a result, when the cooled and solidified male hook element is extracted from the cavity, the male hook element can be prevented from breaking or being torn in the middle of the cavity to generate cracks, and when the male hook element of the obtained male hook fastener is hooked and peeled off with the ring-shaped hook element, the male hook element can also be prevented from breaking or being torn. In addition, since the layer of the layered inorganic particles is arranged in parallel with the surface of the molded object, it is easy to prevent polyethylene glycol from seeping out from the inside of the molded object to the surface of the molded object. On the other hand, in the case where the inorganic particles have a needle-like or granular shape, it is not as difficult to prevent seepage as the layered inorganic particles.

[0058] As specific layered inorganic particles, kaolin, halloysite, talc, pyrophyllite, montmorillonite, vermiculite, mica, etc. can be cited, among which talc is preferred. Talc is a crushed product of hydrous magnesium silicate, which has the following effects: improving the moldability when molding the male-shaped hook and loop fastener, and improving the strength of the obtained male-shaped hook and loop fastener, and making the surface of the obtained male-shaped hook and loop fastener non-sticky.

[0059] That is, the male type molded hook and loop fastener of the present invention is manufactured by extracting the male type hook element from the cavity of the mold, and has the following advantages: when extracting, the male type hook element can be prevented from being torn in the middle of the cavity, and the male type hook element after molding can be prevented from being torn during use. In addition, the surface of the obtained male type molded hook and loop fastener is not sticky even under high humidity conditions. As the average particle size of such layered inorganic particles, particles in the range of 0.1 to 100 μm are preferably preferred, and particles in the range of 1 to 20 μm are particularly preferred. The "average particle size" described here refers to the 50% particle size (D50), which can be measured by a particle size distribution measuring device (made by Nikkiso Co., Ltd., Nanotrac (registered trademark) particle size distribution measuring device UPA-EX150) using the laser Doppler method.

[0060] In addition, the amount of such layered inorganic particles added is 3 to 20 parts by mass relative to 100 parts by mass of PVA. When the amount added is less than 3 parts by mass, the effect of adding the layered inorganic particles as described above cannot be obtained. On the contrary, when the amount added exceeds 20 parts by mass, the fluidity of the resin is reduced, which impairs the moldability. It is preferably in the range of 4 to 15 parts by mass and in the range of 1 / 3 to 2 / 3 of the amount of the above-mentioned polyethylene glycols, and is particularly preferably in the range of 5 to 12 parts by mass and in the range of 2 / 5 to 3 / 5 of the amount of the above-mentioned polyethylene glycols.

[0061] The male type molded hook and loop fastener of the present invention is formed by the PVA, polyethylene glycols and layered inorganic particles as described above. In addition, other substances can be added within the range that does not damage the moldability and the strength, water solubility, etc. of the obtained male type molded hook and loop fastener. For example, by containing colorants such as pigments and dyes, the state of the hook and loop fastener being dissolved in water can be easily observed with the naked eye. In addition, a filler material for reinforcement can also be added.

[0062] The total content of PVA, polyethylene glycols and layered inorganic particles in the material constituting the male-type molded surface fastener is preferably 80% by mass or more, more preferably 90% by mass, further preferably 95% by mass or more, for example 100% by mass.

[0063] Next, a method for molding a male-shaped hook and loop fastener using such a PVA-based water-soluble resin mixture is described. As a specific method for manufacturing the water-soluble male-shaped hook and loop fastener of the present invention, the following method can be used: a molten resin is made to flow into a sheet on the surface of a metal roller having a plurality of cavities in the shape of male hook elements on the surface, and the molten resin is pressed into the cavity, and after cooling and solidification, it is peeled off from the metal roller surface and extracted from the cavity to manufacture a sheet having a plurality of male hook elements on the surface.

[0064] The manufacturing method for extraction from the cavity is described in detail and specifically, by sequentially superimposing a ring-shaped mold having a thickness of 0.2 to 0.5 mm and having cutouts in the shape of male hooking elements such as an inverted J-shape or a Y-shape engraved on the outer circumference and a metal ring without cutouts in such shapes engraved thereon, thereby preparing a mold roller having a plurality of cavities having cutouts in the shape of male hooking elements on its outer circumferential surface.

[0065] It should be noted that, in the case of a male hooking element such as an inverted J-shaped element that can be hooked in one direction, it is preferred to replace half of the annular mold having the inverted J-shaped cutout with an annular mold having a thickness of 0.2 to 0.5 mm and having an inverted J-shaped cutout curved in the opposite direction to the inverted J-shaped shape carved on the outer circumference. At this time, the inverted J-shaped annular mold curved in the opposite direction and the inverted J-shaped annular mold curved in the positive direction can be alternately present, and can be alternately present in units of two or more pieces.

[0066] On the surface of such a metal roller, a plurality of cavities curved in the circumferential direction of the roller are arranged in a row in the circumferential direction, and such rows exist in parallel in the width direction of the metal roller. In the case of an inverted J-shaped shape, the curvature direction of the cavities is reversed in units of one row or in units of multiple rows. At this time, whether in the case of an inverted J-shaped shape or a Y-shaped shape, the cavities become narrower as they go from the metal roller surface to the front end, and gradually curve in the circumferential direction of the metal roller in the middle, with the front end facing the direction close to the metal roller surface.

[0067] As a specific method for the molten resin to flow over the surface of a metal roller and to be molded, the resin melt is extruded into the gap between the metal roller and other drum rollers located at opposite positions and pressed, so that the melt is pressed into and filled in the cavity, and a sheet with uniform thickness is formed on the roller surface. During the rotation of the mold roller, the melt in the cavity is cooled and solidified by the refrigerant that circulates in the roller. At the same time, the substrate of the obtained male molded hook and loop fastener is stretched by a pressure roller whose gap is adjusted in a manner that the thickness is uniform. Then, the cooled sheet is peeled off from the mold roller surface, and the male hook element is extracted from the cavity. Thus, a sheet having multiple male hook elements on the surface, i.e., a male molded hook and loop fastener, can be obtained.

[0068] In the water-soluble male-type molded Velcro of the present invention obtained by such a method, multiple male-type hook elements are arranged in a row, and each hook element has a shape that stands up from the substrate surface, bends in the middle of the column direction, and its front end is facing the direction close to the substrate surface (inverted J-shape), or each hook element has a shape that stands up from the substrate surface, branches out front and back in the middle of the column direction and bends along the column direction, and each front end of the branch is facing the direction close to the substrate surface (Y-shape).

[0069] With such a shape, the male hook element is not easily collapsed by pressure from above, and a plurality of male hook elements cooperate to resist the tensile force in the hook element row direction from the loop-shaped hook element of the hooking object, thereby obtaining a high hooking force.

[0070] It should be noted that in the present invention, the male hook element can be directly erected from the substrate surface, or it can be erected from the ridge-like protrusion formed on the substrate surface. In the case where the male hook element is erected from the ridge-like protrusion in this way, the speed of dissolving in water is accelerated, so it is preferred. The height of the ridge-like protrusion is preferably in the range of 1 / 20 to 1 / 3 of the thickness of the substrate from the substrate surface. In order to make the male hook element stand up from the ridge-like protrusion, methods such as making the diameter of the above-mentioned annular mold with a cavity slightly smaller than the adjacent annular mold without a cavity, or making the center of the annular mold with a cavity deviate from the center of the adjacent annular mold, etc. can be cited. It should be noted that it is not necessary for all male hook elements to stand up from the ridge-like protrusion, and even if a part of them stands up, the corresponding effect can be obtained.

[0071] Figure 1 The male molded hook and loop fastener shown is a case where a plurality of male hook elements (1) are arranged in a row, each hook element has a shape (inverted J-shaped shape) that stands up from the surface of a substrate (2), bends in the middle in the row direction (T), and faces a direction close to the substrate surface. Figure 2The male molded Velcro shown is a case where a plurality of male hook elements (1) are arranged in a row, each hook element has a shape (Y-shaped shape) that stands up from the surface of a base (2), branches out in the front and back direction of the column direction (T) in the middle and bends along the column direction, and each front end of the branch faces a direction close to the surface of the base.

[0072] In particular, in the present invention, when the male hook element has a shape that stands up from the base surface, bends in the column direction from the middle, and its front end is facing the direction close to the base surface (inverted J-shaped shape), the height from the base surface of the male hook element to the top of the male hook element is preferably 1.2 mm or less. In addition, when the male hook element has a shape that has front and rear branches in the middle of the column direction and bends in the column direction respectively, and the front ends of the branches are facing the direction close to the base surface (Y-shaped shape), the height from the base surface of the male hook element to the top of the male hook element is preferably 0.6 mm or less.

[0073] Generally speaking, the height of the male hook element of the male molded Velcro is more than 1.5 mm in most cases, and usually has a height of about 2 to 3 mm. However, in the present invention, from the perspective of water solubility and use, it is preferably a height of less than 1.2 mm or less than 0.6 mm, which is lower than the existing general height.

[0074] In this way, when the height of the male hook element is low, combined with the softness of the male hook element, even if it is installed in a part that easily contacts the skin like a sanitary product, the foreign body sensation can be suppressed, and even if it contacts the skin, it is not easy to cause skin roughness, and the time required for dissolution can be further shortened.

[0075] The lower limit of the height of the male hook element is not particularly limited, and may be, for example, 0.1 mm, 0.2 mm, or 0.4 mm. When the male hook element is in an inverted J-shape, the lower limit of the height of the male hook element may be, for example, 0.4 mm, 0.6 mm, or 0.8 mm.

[0076] In order to obtain such a low-height male hook element, it is obtained by using a metal roller in which the cavity is not engraved too deeply from the surface of the metal roller. Specifically, in the case of manufacturing a water-soluble male molded Velcro tape in which the male hook element has a shape (inverted J-shaped shape) in which the male hook element stands up from the surface of the substrate, bends in the column direction from the middle, and has its front end facing the direction close to the surface of the substrate, it can be easily obtained by using a metal roller in which the depth of the cavity from the surface of the metal roller is less than 1.2 mm at the deepest point. In addition, in the case of manufacturing a water-soluble male molded Velcro tape in which the male hook element has a shape (Y-shaped shape) in which the front and rear branches are in the middle of the column direction and are bent in the column direction respectively, and the front ends of the branches are facing the direction close to the surface of the substrate, it can be easily obtained by using a metal roller in which the depth of the cavity from the surface of the metal roller is less than 0.6 mm at the deepest point.

[0077] In addition, in the water-soluble male-shaped hook and loop fastener of the present invention, the thickness of the base layer is preferably in the range of 0.15 to 0.3 mm from the perspective of rapid water solubility and hook and loop fastener strength. In addition, in the water-soluble male-shaped hook and loop fastener of the present invention, the element density of the male-shaped hook elements is preferably 60 to 160 pieces / cm 2 .

[0078] In addition, for the water-soluble male molded hook and loop fastener of the present invention, the same water-soluble male molded hook and loop fastener can be attached to the back side by hot pressing or by water-soluble adhesive, etc., to make a double-sided hook and loop fastener with male hook elements on the two sides of the surface and back. In addition, in order to have male hook elements on the back side during molding, a metal roller with a cavity on the surface of the metal roller on the back side can be used, so that male hook elements are also present on the back side, and double-sided hook and loop fastener with male hook elements on the two sides of the surface and back can be made. In addition, the water-disintegrable nonwoven fabric with loop fibers on the surface can also be integrated on the back side to make a water-soluble hook and loop fastener with male hook elements on the surface and loop hook elements on the back.

[0079] The water-soluble male-shaped hook and loop fastener of the present invention thus obtained has water solubility that it completely dissolves in water at 25° C. within 20 minutes. In addition, similarly, the water-soluble male-shaped hook and loop fastener of the present invention preferably has a front end portion that is not interrupted in the middle and faces the direction close to the substrate surface, with more than 98% of the male hook elements present on its surface.

[0080] The water-soluble male-shaped molded Velcro of the present invention dissolves upon contact with water, and its hooking ability disappears, and then the water-soluble male-shaped molded Velcro itself completely dissolves and ceases to exist. Therefore, it is not necessary for the loop Velcro that serves as the hooking object to also be water-soluble. If necessary, by making the hooking object also water-soluble, the existence of the Velcro itself can also be completely eliminated.

[0081] Examples of water-soluble loop fasteners used as such hooking objects include those formed from water-soluble fibers that are soluble in water at room temperature. In particular, PVA-based fibers are preferred as water-soluble fibers because they have excellent tensile strength and excellent handling properties. For example, there can be mentioned: water-soluble PVA fibers (Kuralon K-II (registered trademark) WN2) sold by Kuraray Co., Ltd., obtained by dissolving PVA having a saponification degree of 85 to 90 mol% and a polymerization degree of 1500 to 2000 in dimethyl sulfoxide and subjecting the obtained spinning solution to dry-wet or wet spinning in a methanol bath; water-soluble PVA fibers obtained by mixing ethylene oxide adducts of polyethylene glycol and sorbitol with PVA having a saponification degree of 60 to 80 mol% and a polymerization degree of 300 to 700 and subjecting the mixture to melt spinning; water-soluble PVA fibers obtained by dissolving PVA having a saponification degree of 85 to 95 mol% in water and subjecting the obtained spinning solution to wet spinning in a bath of saturated sodium sulfate aqueous solution, etc.

[0082] Examples of loop fasteners made of such water-soluble fibers include nonwoven fabrics made of such water-soluble fibers and loop fasteners in which loops made of the water-soluble fibers are present on the surface of knitted fabrics.

[0083] Specifically, in the case of nonwoven fabric, water-soluble fibers are formed into a web, entangled by needle punching or the like, and the surface is raised as necessary so that loops of the water-soluble fibers are present on the surface.

[0084] In addition, in the case of knitted fabrics, there can be mentioned fabric-like loop fasteners, wherein the fabric-like loop fasteners use water-soluble fibers as yarns, and use the yarns as warp and weft to make a fabric, and further weave such yarns into the fabric in parallel with the warp, and protrude in a loop shape at some parts of the fabric surface, and the knitted loop fasteners use yarns formed by such water-soluble fibers to make a knitted fabric, and the knitted fabric surface is raised by needle clothing, etc., so that loops formed by the water-soluble fibers exist on the fabric surface. In addition, in the case where the water-soluble fiber is a multifilament yarn, the multifilament yarn can also be used as a warp and weft to make a fabric, and further loop-shaped hooking elements are woven into the fabric in parallel with the warp, and protrude in a loop shape at some parts of the fabric surface, thereby making a fabric-like loop fastener.

[0085] Alternatively, a loop fastener may be one in which such a water-soluble multifilament yarn is converted into a nonwoven fabric by a spunbond method and the surface thereof is raised so that loops formed of water-soluble fibers protrude on the surface.

[0086] In the case of a loop fastener, it is preferred that the back surface or a portion of the back surface be thermally compressed to fix the fibers so that the loop-shaped hooking elements are not pulled out of the base fabric.

[0087] However, the loop fastener formed by water-soluble fibers that dissolve in water at room temperature has the following problems: the room-temperature water-soluble fibers that constitute the loop hooking elements have stickiness under high humidity conditions; the loop hooking elements do not stand up from the surface of the base fabric but fall down, and cannot be fully hooked with the male hooking elements; in addition, even if they can be hooked, the loop hooking elements are easily cut, and a fastener with high hooking force cannot be obtained; furthermore, for fibers that dissolve in water at room temperature, in the manufacturing process, storage process, and circulation process of the loop fastener, consumers who have purchased such loop fasteners are also required to manage / store them in a manner that they are not exposed to high humidity conditions and thus do not come into contact with moisture.

[0088] As a water-soluble loop fastener that gets rid of such problems, there is a loop fastener made of water-soluble fibers that do not dissolve in water at room temperature but begin to dissolve when in contact with warm water at 50 to 80°C. Such water-soluble loop fastener cannot be considered to be soluble in water at room temperature, but can be dissolved by the warm water used when disposable products equipped with the fastener are recycled and reused. Therefore, from the perspective of environmental issues, it has a high utilization value.

[0089] Specific examples of such loop fasteners that dissolve in warm water include: water-soluble loop fasteners in which loop-shaped hook elements formed by water-soluble PVA fibers having a water dissolution temperature of 50 to 80°C stand up from the surface of a base fabric formed by the fibers. Preferred examples thereof include: a woven fabric formed by dissolving PVA having a saponification degree of 90 to 97 mol % and a polymerization degree of 1200 to 2000 in the above-mentioned dimethyl sulfoxide and wet-spinning or dry-wet-spinning the obtained spinning solution in methanol; a non-woven fabric having a large amount of loop fasteners containing PVA fibers having a saponification degree of 90 to 97 mol % and a polymerization degree of 1200 to 2000; A loop hook fastener having a loop-shaped hook element formed by a loop of a plurality of fibers; a PVA resin having a saponification degree of 90 to 97 mol%, a polymerization degree of 250 to 500, preferably 300 to 450, more preferably 350 to 400, and copolymerized with 5 to 10 mol%, preferably 6.5 to 9.5 mol%, more preferably 7.5 to 9.2 mol% of ethylene, and an ethylene oxide adduct of polyethylene glycol and sorbitol is mixed as described above, and melt-spun, and the obtained multifilament yarn is made into a warp knitted fabric, and a warp knitted fabric having a large number of loops formed by the multifilament yarn on the surface. From the aspect of hooking force, the above-mentioned warp knitted fabric is particularly preferred.

[0090] Furthermore, in the case of a water-soluble hook and loop fastener in which the male hook elements are present on the surface and the loop hook elements are present on the back as described above, and the two are joined in a manner in which the male hook elements are on the surface and the loop hook elements are present on the back of a portion away from the portion where the male hook elements are present, the water-soluble loop fastener is required to have sufficient tensile strength alone, and therefore, the above-mentioned warp knitted fabric is preferred as the water-soluble loop fastener.

[0091] In addition, although such a loop fastener made of water-soluble fibers having a water dissolution temperature of 70 to 90° C. does not dissolve in water at room temperature, it can be easily dissolved in warm water. Furthermore, even if it is discarded, it can be decomposed in a short period of time, so it is environmentally friendly.

[0092] The water-soluble male-shaped hook and loop fastener obtained according to the present invention has sufficient hooking force and has the property of being quickly dissolved in water at room temperature, and no harmful substances to the human body are added. Therefore, the water-soluble male-shaped hook and loop fastener can be used alone or in combination with the water-soluble female-shaped hook and loop fastener as a fixing material for fixing physiological products to underwear, or as a waist fixing material for disposable diapers, or as a fixing material for other disposable products.

[0093] In addition, by putting the article fixed with the Velcro into water, the fixation based on the Velcro disappears immediately, and it can be used for the purpose of unfolding the article in the water or on the water surface, etc. For example, it can be used for fixing and bundling oil booms, shielding sheets, etc. when not in use, and the oil booms, shielding sheets, etc. are used to block the spread and outflow of oil and polluted water caused by oil tankers, factories, etc. to the sea surface, rivers, etc. In addition, in the case of the above-mentioned water-soluble Velcro having male hook elements on the surface and female hook elements on the back, it can also be used as a self-hooking water-soluble bundling tape, fixing tape, etc. that releases the bundling by wetting.

[0094] Such a water-soluble Velcro (hereinafter referred to as water-soluble loop Velcro) having male hook elements on the surface and female hook elements (hereinafter referred to as loop hook elements) on the back side can be the following Velcro: a water-soluble male molded Velcro and a water-soluble loop Velcro are overlapped back to back with the hook elements on the outside respectively, and the two are joined together in certain parts by a water-soluble adhesive and hot pressing. Alternatively, the end of a water-soluble loop fastener having a loop-shaped hook element on the back side can be overlapped with the end of a water-soluble male molded fastener having a male hook element on the surface in a manner that the two do not overlap except for the end portions and that the side having the male hook element is the surface side and the side having the loop-shaped hook element is the back side, and the two can be joined at the overlapping portion by a water-soluble adhesive and heat pressing, and the two can be joined in a manner that the male hook element is the surface and the loop-shaped hook element is present on the back side of a portion away from the portion where the male hook element is present (that is, the portion where the male hook element is present and the portion where the loop-shaped hook element is present are not back-to-back, but are sandwiched and joined and extend in directions away from each other), thereby obtaining the fastener.

[0095] Example

[0096] The present invention is described below by way of examples. In the examples, the hooking force was measured using E40000 (manufactured by Kuraray Adhesive Fastener Co., Ltd.) as a loop fastener to be hooked, and the initial hooking force and the hooking force after 10 repetitions of hooking and peeling were measured in accordance with JIS L3416:2000.

[0097] In addition, regarding the water solubility of the obtained water-soluble male-type molded fastener, 100cc of water at a water temperature of 25°C was added to a 200ml beaker, 0.025g of the water-soluble male-type molded fastener was placed in the water, and the time required for complete dissolution was measured under stirring (using a magnetic stirrer, a stirring bar with a length of 12mm, and stirring at a speed of 1500rpm / min).

[0098] In addition, regarding the shape completeness of the male hook elements of the obtained water-soluble male-type molded fastener, the number of hook elements that did not have a front end facing in a direction close to the substrate surface and were interrupted in the middle were counted among 100 male hook elements randomly selected from the water-soluble male-type molded fastener.

[0099] In addition, regarding the softness of the obtained water-soluble male-type molded surface fastener, a male weighing 60 kg stepped on the surface fastener barefoot 10 times, and the state of the hooking elements was observed.

[0100] In addition, the presence or absence of surface stickiness was determined by touching the surface of the surface of the surface of the surface of the surface after the obtained surface was left to stand for 4 hours under the conditions of a temperature of 30° C. and a humidity of 100%.

[0101] Example 1

[0102] As a mold, a 0.30mm thick and 212mm diameter ring mold with a hook-shaped hook element (inverted J-shaped hook element) shape engraved on the outer circumference with a depth of 0.90mm, a 0.30mm thick and 212mm diameter metal ring without such a shape engraved, a 0.30mm thick and 212mm diameter ring mold with a hook-shaped hook element shape engraved on the outer circumference in the opposite direction to the hook-shaped hook element shape, and a 0.30mm thick and 212mm diameter metal ring without such a shape engraved were sequentially superimposed to prepare a mold roller having a width of 120mm having a plurality of inverted J-shaped hook element cavities and hook element cavities in the opposite direction on its outer circumferential surface. It should be noted that the diameter of the ring mold with the hook-shaped hook element shape engraved on the outer circumference was slightly smaller than the diameter of the rings adjacent to it on both sides (to the extent that a ridge-like protrusion with a height of 0.03mm described later was formed).

[0103] Relative to 100 parts by mass of PVA obtained by saponifying vinyl acetate with a polymerization degree of 500 to a saponification degree of 74 mol%, 20 parts by mass of polyethylene glycol with a number average molecular weight of 400 and 10 parts by mass of talc (average particle size: 4 μm) are mixed, the obtained composition is melted at 190°C, and the obtained melt is extruded into the gap between the above-mentioned mold roller and other drum rollers existing in relative positions, and pressed by the mold roller and the drum roller, thereby filling the resin composition in the cavity and forming a sheet with uniform thickness on the roller surface, and the resin composition in the cavity is cooled by water circulating during the rotation of the mold roller, and then stretched by a clamping roller after the gap is adjusted so that the substrate thickness becomes 0.20 mm, and the cooled and solidified sheet is peeled off from the surface of the mold roller to manufacture a water-soluble male molded hook and loop fastener.

[0104] In the obtained water-soluble male molded hook and loop fastener, a plurality of male hook elements are arranged in a row, each male hook element has a shape (inverted J-shape) that stands up from a ridge-like protrusion (height 0.03 mm) formed on the surface of the substrate, bends in the row direction from the middle, and faces the direction close to the substrate surface, and the height is 0.94 mm. In addition, the element density is 110 pieces / cm 2 In addition, the thickness of the substrate is 0.21 mm.

[0105] The properties of the obtained water-soluble male-shaped hook and loop fastener are shown in the following Table 1. As can be seen from the table, there are basically no problems with water solubility, hooking force, state of hooking elements on the surface, softness and surface tackiness, and it is suitable for use as a material for attaching sanitary products to underwear, and there will be no problem even if it is flushed into the toilet after use.

[0106] In addition, as the hooking object of such a water-soluble male-shaped hook and loop fastener, the following non-woven fabric is used for hooking: water-soluble PVA fibers (Kuralon K-IIWN2 thickness: 2.2 dtex, fiber length: 51 mm) manufactured by Kuraray Co., Ltd. that can be dissolved in water at room temperature are made into a net, and are entangled by needle punching, and then the surface is raised by needle clothing, and loops formed by the fibers exist on the surface, and the unit area weight of the non-woven fabric is 200 g / m 2 The hooking force was high, slightly lower than the value in Table 1, and the hooking property was excellent. In addition, when such a water-soluble male-shaped hook and non-woven fabric formed of water-soluble fibers were hooked together, a 2 cm square was cut and immersed in stirring 25°C normal temperature water, and its dissolution state was observed. As a result, the hooking of the hook and fastener was peeled off in 3 minutes, and both were completely dissolved in 15 minutes. In addition, as the hooking object of such a water-soluble male-shaped fastener, the following loop fastener was used for hooking: the loop fastener is a warp knitted fabric with a coil row of 75 c / inch and a coil row of 28 w / inch formed by water-soluble PVA-based fibers manufactured by Kuraray Co., Ltd. that are soluble in water at 80°C (Mintval CR-700P RS41T-6, a multifilament yarn obtained as follows: PVA100 having a polymerization degree of 390 and a saponification degree of 95 mol% copolymerized with 8.5 mol% of ethylene, 2 mol% of ethylene oxide adduct 8 is added to sorbitol, the obtained resin is melt-spun, and 12 filaments having a thickness of 8.5 dtex obtained thereby are gathered), and the weight per unit area is 145 g / m 2 , the circle height is 1.1mm.

[0107] Compared with the above-mentioned nonwoven fabric, the loop hook element of this loop hook tape does not fall down, the ratio of standing up from the base fabric surface is high, and the hook force is high compared with the above-mentioned nonwoven fabric. Among them, although it does not dissolve in normal temperature water of 25°C, it completely dissolves in warm water of 80°C in 10 minutes, and when buried in the soil, it completely disappears in 24 weeks. In addition, in the case of this water-soluble warp knitted fabric, compared with the above-mentioned water-soluble nonwoven fabric, humidity management is not required in terms of production and storage, and it can be handled like ordinary synthetic fibers.

[0108] [Table 1]

[0109]

[0110] The unit of shear strength is N / cm 2 , the unit of peel strength: N / cm

[0111] Examples 2 to 5, Comparative Examples 1 to 4

[0112] The PVA used in the above embodiment was changed to a PVA having a polymerization degree and a saponification degree shown in Table 2 below. A water-soluble male-shaped hook and loop fastener was manufactured in the same manner as in Example 1. The obtained water-soluble male-shaped hook and loop fasteners were the same as those in Example 1. A plurality of male-shaped hook elements were arranged in a row. Each hook element was in a shape (inverted J-shaped) that stood up from the substrate surface, bent in the middle of the row direction, and the front end thereof was oriented toward the direction close to the substrate surface. The height of the male-shaped hook element was 0.94 mm. In addition, the element density was 110 pieces / cm 2 , In addition, the thickness of the substrate is 0.25m.

[0113] [Table 2]

[0114] PVA degree of polymerization PVA saponification degree (mol%) Example 2 350 74 Example 3 650 75 Comparative Example 1 250 74 Comparative Example 2 1000 76 Example 4 500 68 Example 5 500 78 Comparative Example 3 500 52 Comparative Example 4 500 94

[0115] The performance of the 8 kinds of water-soluble male-shaped fasteners obtained are shown in the following Table 3. It is clear from this table that the water-soluble male-shaped fasteners of Examples 2 to 5 have no major problems in any of the hooking force, the state of the hooking elements on the surface, the softness and the surface tackiness. In addition, as a specific use, they can be used as a material for attaching sanitary products to underwear, and regarding water solubility, there is no problem even if they are flushed into the toilet after use.

[0116] In contrast, in the case of PVA with a low degree of polymerization in Comparative Example 1, the strength of the male hook element is low and it is easy to break. In addition, in the case of Comparative Example 2 with a high degree of polymerization, the melt viscosity is high, gelation occurs in the mold, and the molten resin cannot reach the front end of the cavity. There are about 20% of the male hook elements that do not extend to the front end. In addition, the water solubility is also poor.

[0117] In the case of Comparative Example 3, it was too soft and could not obtain the strength / elastic modulus required for the male hook element of the hook and loop fastener, and the hook force was low. In the case of Comparative Example 4, it was poor in water solubility, and the moldability was reduced, gelation was easily generated, the molten resin did not reach the end of the cavity, and about 15% of the male hook elements did not extend to the front end.

[0118] [Table 3]

[0119]

[0120] The unit of shear strength is N / cm 2 , the unit of peel strength: N / cm

[0121] Examples 6 to 7, Comparative Examples 5 to 9

[0122] In Example 1, a water-soluble male-type molded surface fastener was produced in the same manner as in Example 1 except that the mixing ratio of PVA, polyethylene glycol, and talc used for molding was changed as described in Table 4 below.

[0123] The obtained water-soluble male-shaped hook and loop fasteners are the same as those of Example 1. A plurality of male-shaped hook elements are arranged in a row. Each hook element is in a shape (inverted J-shaped) that stands up from the substrate surface, bends in the middle of the row direction, and faces the substrate surface. The height of the male-shaped hook element is 0.94 mm, and the element density is 110 / cm 2 , the thickness of the substrate is 0.25m.

[0124] [Table 4]

[0125] PVA (parts by mass) PEG*(parts by weight) Talc (parts by mass) Example 6 100 10 5 Example 7 100 25 15 Comparative Example 5 100 40 25 Comparative Example 6 100 3 2 Comparative Example 7 100 0 10 Comparative Example 8 100 20 0 Comparative Example 9 100 0 0

[0126] PEG*: Short for polyethylene glycol.

[0127] The performance of the obtained 7 kinds of water-soluble male-shaped fasteners are shown in the following Table 5. It is clear from this table that, compared with the water-soluble male-shaped fastener of Example 1, the water-soluble male-shaped fasteners of Examples 6 and 7 are slightly inferior in water solubility, hooking force, state of hooking elements on the surface, softness and surface tackiness, but they are not a big problem. In addition, as a specific use, they can be used as a material for installing sanitary products on underwear, and there will be no problem even if they are flushed into the toilet after use.

[0128] In contrast, the water-soluble male-type molded hook and loop fastener of Comparative Example 5, which contains high amounts of both polyethylene glycol and talc, has poor moldability. The male-type hook elements are often interrupted in the middle of being pulled out of the cavity, and polyethylene glycol oozes out on the surface. Despite the high amount of talc added, the surface is also sticky. In addition, the male-type hook elements of the obtained male-type molded hook and loop fastener do not have sufficient strength.

[0129] On the other hand, Comparative Example 6 is a case where the amounts of polyethylene glycol and talc are both small, and Comparative Example 7 is a case where no polyethylene glycol is added at all, and Comparative Example 9 is a case where no polyethylene glycol and talc are added at all. In these cases, gelation occurs during the molding process, and male-type molded Velcro with commercial value cannot be manufactured. In particular, in Comparative Examples 7 and 9, even the molding of the Velcro cannot be carried out.

[0130] In contrast, Comparative Example 8 is a case where talc is not added at all. In this case, although the male-type molded hook and loop fastener can be produced under the condition of poor moldability, the male-type molded hook and loop fastener obtained has the situation that the male-type hook elements break in the middle and the surface is severely sticky, and it has no commercial value in any case.

[0131] [Table 5]

[0132]

[0133] The unit of shear strength is N / cm 2 , the unit of peel strength: N / cm

[0134] Example 8

[0135] In the above-mentioned Example 1, as the mold roller for molding, a ring-shaped mold with a cavity depth of 1.2 mm and a thickness of 0.3 mm was used, and the same resin mixture as in Example 1 was used to manufacture a water-soluble male molded hook and loop fastener. The obtained water-soluble male molded hook and loop fastener had an element density of 136 pieces / cm 2 The surface of the hook tape is as follows: Figure 3 That is, it has a plurality of male hook elements arranged in a row, each hook element is in a shape (inverted J-shape) with its front end facing the direction close to the substrate surface and the substrate thickness is 0.23 mm. The properties of the obtained water-soluble male molded hook and loop fastener are shown in Table 6 below.

[0136] As can be seen from the table, although the water solubility is somewhat inferior to that of Example 1, there are no problems in terms of hooking force, the state of the hooking elements on the surface, softness, and surface tackiness. However, in applications that come into contact with the skin, such as attachment materials on underwear such as sanitary products, the skin feel is slightly inferior. In particular, in terms of flushing down the toilet after use, there is a disadvantage that the dissolution time is slightly longer.

[0137] Example 9

[0138] In the above-mentioned Example 1, as the shape of the cavity of the mold roller used for molding, a ring-shaped mold with a thickness of 0.3 mm and a Y-shaped cutout with a depth of 0.55 mm engraved on the outer circumference was used, and the same resin mixture as in Example 1 was used to manufacture a water-soluble male molded hook and loop fastener. For the obtained water-soluble male molded hook and loop fastener, the male hook elements present on its surface are arranged in a row, and each hook element has a shape that stands up from the surface of the substrate, branches forward and backward in the column direction in the middle and bends along the column direction, and each front end of the branch faces the direction close to the surface of the substrate, that is, it has a Y-shaped shape, its height is 0.55 mm, and the element density is 147 pieces / cm 2 The thickness of the substrate was 0.18 mm. The properties of the obtained water-soluble male-shaped hook and loop fastener are shown in Table 6 below.

[0139] As can be seen from the table, the water solubility, hooking force, state of the hooking elements on the surface, and softness are as good as those in Example 1. In addition, the stickiness on the surface is not felt as in Example 1, and it is excellent in terms of ease of use. In addition, for uses that come into contact with the skin, such as attachment materials on underwear such as sanitary products, it is also soft and excellent in terms of skin touch. In addition, even if it is flushed into the toilet after use, it can be quickly dissolved, so it is an excellent water-soluble male molded hook and loop fastener without any problems.

[0140] [Table 6]

[0141]

[0142] The unit of shear strength is N / cm 2 , the unit of peel strength: N / cm.

Claims

1. A water-soluble male-shaped hook and loop fastener having a substrate and a plurality of male-shaped hook elements protruding from the surface of the substrate, and satisfying the following (1) to (3), (1) A plurality of male hook elements are arranged in a row, each male hook element having a shape that stands up from the substrate surface, bends in the middle of the male hook element toward the column direction, and its front end faces a direction close to the substrate surface; or each male hook element has a shape that stands up from the substrate surface, branches out in the middle of the male hook element toward the front and back of the column direction and bends in the column direction, and each front end of the branch faces a direction close to the substrate surface; (2) The base and the male hook element are both formed of a mixture of polyvinyl alcohol, a polyol or an ethylene oxide polymer, and layered inorganic particles, wherein the mixing ratio is 5 to 30 parts by weight of the polyol or the ethylene oxide polymer, and 3 to 20 parts by weight of the layered inorganic particles relative to 100 parts by weight of the polyvinyl alcohol; (3) The degree of polymerization of polyvinyl alcohol is 300 to 700, and the degree of saponification is 60 to 80 mol%. The polyol or ethylene oxide polymer is polyethylene glycol, and its number average molecular weight is 300-700.

2. The water-soluble male-type molded hook and loop fastener according to claim 1, wherein: When the male hook element has a shape that stands up from the substrate surface, bends in the column direction from the middle, and faces the direction close to the substrate surface, the height from the substrate surface of the male hook element to the top of the male hook element is 1.2 mm or less, When the male hook element has a shape in which front and rear branches are branched in the column direction and bent in the column direction, and the front ends of the branches are directed toward the direction close to the substrate surface, the height from the substrate surface of the male hook element to the top of the male hook element is less than 0.6 mm.

3. The water-soluble male-type molded hook and loop fastener according to claim 1 or 2, wherein: The layered inorganic particles are talc.

4. The water-soluble male-type molded hook and loop fastener according to claim 1 or 2, wherein: The water-soluble male molded hook and loop fastener has water solubility that it completely dissolves in water at 25°C within 20 minutes.

5. The water-soluble male-type molded hook and loop fastener according to claim 1 or 2, wherein: More than 98% of the male hook elements have a leading end portion which is not interrupted in the middle and faces toward the direction close to the surface of the substrate.

6. A combination of the water-soluble male-type molded hook and loop fastener according to any one of claims 1 to 5 and a water-soluble loop fastener formed of water-soluble fibers.

7. The combination according to claim 6, wherein: The water-soluble loop fastener is a nonwoven fabric or a knitted fabric formed of polyvinyl alcohol-based fibers, and loops formed of the same type of fibers as the polyvinyl alcohol-based fibers are present on the surface of the nonwoven fabric or the knitted fabric.

8. A method for manufacturing a water-soluble male-shaped hook and loop fastener, the method comprising: A molten mixture satisfying the following (4) and (5) is flowed over the surface of a metal roll satisfying the following (A), and the molten mixture is pressed into a cavity in the shape of a male hook element formed by perforating the surface of the metal roll. In this state, the molten mixture is cooled and solidified, and then peeled off from the surface of the metal roll and extracted from the cavity. (A) The metal roller is formed by stacking a thin annular mold having a plurality of cavities in the shape of male hook elements carved on the outer circumference, wherein the plurality of cavities for male hook elements are arranged in a row in the circumferential direction of the roller on the surface of the metal roller, each cavity is bent in the row direction of the cavity midway and its front end is close to the surface of the metal roller, or each cavity is branched into two branches midway and each branch is bent in the row direction and its front end is close to the surface of the metal roller; (4) a mixture of polyvinyl alcohol, a polyol or an ethylene oxide polymer, and layered inorganic particles, wherein the mixing ratio is 5 to 30 parts by weight of the polyol or the ethylene oxide polymer, and 3 to 20 parts by weight of the layered inorganic particles relative to 100 parts by weight of the polyvinyl alcohol; (5) The degree of polymerization of the polyvinyl alcohol is 300 to 700, and the degree of saponification is 60 to 80 mol %, The polyol or ethylene oxide polymer is polyethylene glycol, and its number average molecular weight is 300-700.

9. The method for manufacturing the water-soluble male-type molded hook and loop fastener according to claim 8, wherein: When the cavity has a shape that is bent in the row direction of the cavity midway and the front end thereof is close to the surface of the metal roller, the depth of the cavity from the surface of the metal roller is 1.2 mm or less at the deepest point, or When the cavity has a shape in which two branches are branched in the middle and each branch is bent in the column direction and the tip end is close to the metal roller surface, the depth of the cavity from the metal roller surface is 0.6 mm or less at the deepest point.

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