Fastener tape, slide fastener provided with said fastener tape, and method for producing fastener tape

Abstract

This fastener tape (10) is provided with base fabrics (11, 32) and water cut-off films (12, 33) attached to at least one surface of the base fabrics (11, 32). The water cut-off films (12, 33) have a stack structure comprising: a surface layer (13) comprising a film using an aqueous polyurethane produced by an acetone method as a raw material; and an adhesive layer (14) being adjacent to the surface layer (13) and comprising a cured product of an adhesive containing an aqueous polyurethane produced by the acetone method.

Description

Fastener tape, slide fastener including said fastener tape, and method for manufacturing fastener tape

[0001] The present invention relates to a waterproof fastener tape. The present invention also relates to a slide fastener provided with the waterproof fastener tape. The present invention also relates to a method for manufacturing the waterproof fastener tape.

[0002] Slide fasteners are widely used as opening and closing devices for everyday items such as clothing, bags, shoes, and miscellaneous goods, but are also used in protective clothing such as space suits, chemical protective suits, diving suits, and survival suits, as well as covers for transport containers and tents, etc. For such special applications, slide fasteners are also required to be waterproof.

[0003] A slide fastener generally consists of three main parts: a pair of long fastener tapes, fastener elements that are the fastener's engaging portions sewn along one side edge of each tape, and a slider that controls the opening and closing of the fastener by engaging and separating the fastener elements. A known slide fastener has a waterproof synthetic resin film attached to the fastener tapes, and when engaged, the synthetic resin films of the left and right fastener tapes come into close contact, thereby achieving waterproofness. Polyurethane film is a known example of such a synthetic resin film.

[0004] In recent years, there has been a demand for product manufacturing that takes into consideration the environmental impact of organic solvents and the health of workers. Therefore, there is a desire to shift to environmentally friendly waterproof slide fasteners that reduce the use of organic solvents. International Publication No. 2014 / 010019 (Patent Document 1) discloses a fastener tape in which an aqueous polyurethane film is bonded via an aqueous polyurethane adhesive. In the examples of Patent Document 1, Resamine D from Dainichiseika Color & Chemicals Mfg. Co., Ltd. is used as the aqueous polyurethane adhesive and the aqueous polyurethane film.

[0005] International Publication No. 2014 / 010019

[0006] Known methods for producing aqueous polyurethanes include forced emulsification and self-emulsification. Resamine D, used in the examples of Patent Document 1, is produced by the forced prepolymer emulsification method and is provided in the form of an aqueous polyurethane dispersion. In the forced prepolymer emulsification method, N-methylpyrrolidone (NMP) is often used as a viscosity modifier during the polyurethane production process, and it tends to remain in the aqueous polyurethane dispersion. However, NMP has recently been added to the list of substances subject to regulation under the European REACH regulation, and there is a demand for environmentally friendly aqueous polyurethanes that do not use NMP during the production process.

[0007] On the other hand, waterproof slide fasteners are also required to have practical properties such as adhesion between the water-stopping film and base fabric that make up the fastener tape, and durability in reciprocating opening and closing when applied to slide fasteners.

[0008] In view of the above circumstances, one object of the present invention is to provide a fastener tape that is environmentally friendly and practical for use in a waterproof slide fastener. Another object of the present invention is to provide a slide fastener including such a fastener tape. Another object of the present invention is to provide a method for manufacturing such a fastener tape.

[0009] The present inventors have conducted extensive research to solve the above problems and have found that it is effective to use aqueous polyurethane produced by the acetone method in water-stopping films and adhesives.

[0010] [Aspect 1] A fastener tape comprising a base fabric and a water-stop film attached to at least one surface of the base fabric, wherein the water-stop film has a laminated structure comprising a surface layer made of a film using aqueous polyurethane produced by the acetone method as a raw material, and an adhesive layer adjacent to the surface layer and made of a cured product of an adhesive containing aqueous polyurethane produced by the acetone method. [Aspect 2] The fastener tape according to Aspect 1, wherein the aqueous polyurethane used as a raw material for the film and the aqueous polyurethane contained in the adhesive both contain polycarbonate-based polyurethane. [Aspect 3] The fastener tape according to Aspect 1 or 2, wherein the adhesive is a two-component adhesive that cures by mixing at least an aqueous polyurethane having hydroxy groups produced by the acetone method as a main component and an isocyanate compound as a curing agent. [Aspect 4] The fastener tape according to Aspect 3, wherein the aqueous polyurethane having hydroxy groups produced by the acetone method as a main component contains polycarbonate-based polyurethane having hydroxy groups. [Aspect 5] The fastener tape according to Aspect 4, wherein the cured product of the adhesive is a cured product obtained by at least mixing the base agent and the curing agent so that the molar ratio (NCO / OH) of the isocyanate groups (NCO) of the isocyanate compound serving as the curing agent to the hydroxyl groups (OH) of the aqueous polyurethane serving as the base agent is 1.4 or higher. [Aspect 6] The fastener tape according to any one of Aspects 1 to 5, wherein the aqueous polyurethane used as the raw material for the film, produced by the acetone method, is a mixture of a low-molecular-weight aqueous polyurethane having a weight-average molecular weight of 7,000 to 15,000 and a high-molecular-weight aqueous polyurethane having a weight-average molecular weight of 18,000 to 32,000, in a mass blending ratio of low-molecular-weight aqueous polyurethane:high-molecular-weight aqueous polyurethane = 5:95 to 20:80. [Aspect 7] A slide fastener comprising the fastener tape according to any one of Aspects 1 to 6.[Aspect 8] A method for producing a fastener tape, comprising the steps of bonding a surface layer made of a film using an aqueous polyurethane produced by the acetone method as a raw material to a base fabric via an adhesive containing an aqueous polyurethane produced by the acetone method, and curing the adhesive sandwiched between the surface layer and the base fabric. [Aspect 9] A method for producing a fastener tape according to Aspect 8, wherein the aqueous polyurethane used as a raw material for the film and the aqueous polyurethane contained in the adhesive both contain polycarbonate-based polyurethanes. [Aspect 10] A method for producing a fastener tape according to Aspect 8 or 9, wherein the adhesive is a two-component adhesive that cures by mixing at least an aqueous polyurethane having hydroxy groups produced by the acetone method as a main component and an isocyanate compound as a curing agent. [Aspect 11] A method for producing a fastener tape according to Aspect 10, wherein the aqueous polyurethane having hydroxy groups produced by the acetone method as a main component contains a polycarbonate-based polyurethane having hydroxy groups. [Aspect 12] The method for producing a fastener tape according to Aspect 11, wherein the cured product of the adhesive is a cured product obtained by at least mixing a base agent and a curing agent so that the molar ratio (NCO / OH) of the isocyanate group (NCO) of the isocyanate compound serving as the curing agent to the hydroxy group (OH) of the aqueous polyurethane serving as the base agent is 1.4 or more. [Aspect 13] The method for producing a fastener tape according to any one of Aspects 8 to 12, wherein the aqueous polyurethane binder used as a raw material for the film, produced by the acetone method, is a mixture of a low molecular weight aqueous polyurethane having a weight average molecular weight of 7,000 to 15,000 and a high molecular weight aqueous polyurethane having a weight average molecular weight of 18,000 to 32,000, in a mass blending ratio of low molecular weight aqueous polyurethane:high molecular weight aqueous polyurethane = 5:95 to 20:80.

[0011] In aqueous polyurethanes produced by the acetone process, there is almost no risk of residual organic solvents, such as NMP, which have a high environmental impact. Acetone has a low environmental impact and a low boiling point, so it can be easily removed from polyurethanes by distillation, and it can also be easily recovered and reused.

[0012] Furthermore, aqueous polyurethanes produced by the acetone method can provide excellent adhesion and chemical resistance when used as an adhesive between the waterstop film and base fabric that make up a fastener tape. Furthermore, in a preferred embodiment, they exhibit excellent reciprocating opening and closing durability when applied to a slide fastener. While not intending to limit the present invention by theory, this is presumably due to the following reasons. The acetone method allows for control of the polyurethane's molecular weight in the acetone solvent, enabling the production of polyurethanes with a more uniform particle size distribution than the prepolymer method using NMP. The polyurethane is ultimately provided in a water-dispersed state (aqueous polyurethane), and the highly uniform particle size distribution improves the homogeneity of bonding between the polyurethane particles when the aqueous polyurethane is heated to remove moisture. This contributes to improved adhesive strength and reciprocating opening and closing durability. Furthermore, when aqueous polyurethanes produced by the acetone method are used as both a waterstop film and an adhesive, the high affinity between the two contributes to improved adhesive strength between the waterstop film and base fabric.

[0013] However, the mechanism of the effects obtained by using aqueous polyurethane is based on speculation, and elucidating the cause requires advanced analytical techniques and takes a long time. Therefore, in this specification, the aqueous polyurethane to be used is specified by its manufacturing method.

[0014] Fig. 5 is a schematic diagram showing a laminated structure of fastener tapes of a slide fastener according to one embodiment of the present invention. Fig. 6 is a plan view of a slide fastener according to one embodiment of the present invention. Fig. 7 is a cross-sectional view of a slide fastener according to one embodiment of the present invention. Fig. 8 is a perspective cross-sectional view of a slide fastener according to one embodiment of the present invention. Fig. 9 is a perspective view of a fastener stringer constituting a slide fastener according to another embodiment of the present invention. Fig. 10 is a cross-sectional view of the slide fastener according to Fig. 5.

[0015] FIG. 1 shows the laminated structure of a fastener tape of a slide fastener according to one embodiment of the present invention. The fastener tape 10 includes a base fabric 11 and a water-stop film 12 attached to at least one surface of the base fabric 11. The water-stop film 12 has a laminated structure including a surface layer 13 made of a film using aqueous polyurethane produced by the acetone method as a raw material, and an adhesive layer 14 adjacent to the surface layer 13 and made of a cured product of an adhesive containing aqueous polyurethane produced by the acetone method. In other words, the fastener tape 10 includes the adhesive layer 14 on the base fabric 11 side of the surface layer 13, and the adhesive layer 14 bonds the base fabric 11 and the surface layer 13 together. As shown in FIG. 1 , the fastener tape 10 has a laminated structure in which the surface layer 13, adhesive layer 14, and base fabric 11 are laminated in this order from the top of the page in a cross-sectional view.

[0016] (1. Base Fabric) The material of the base fabric 11 can be natural or synthetic fibers commonly used for fastener tapes, and is not particularly limited, but examples thereof include polyamide fibers, polyester fibers, acrylic fibers, etc. The base fabric 11 can be produced by weaving or knitting one or more of these synthetic fibers. Typically, it can be woven or knitted with polyester fibers.

[0017] An example of a procedure for adhering the waterstop film 12 to the base fabric 11 will be described. A cured surface layer 13 of the waterstop film 12 is prepared, and an adhesive is applied to its surface and then heated and dried. Drying can be performed, for example, in a thermostatic oven or an infrared dryer. Drying conditions are not limited, but for example, drying in a thermostatic oven is preferably performed for 5 to 8 minutes at a temperature of 70 to 90°C. For drying in an infrared dryer, drying is preferably performed for 4 to 8 minutes at a temperature of 70 to 90°C. If the moisture content is low, i.e., excessive heating and drying, the curing reaction progresses, causing the adhesive to polymerize and resulting in a loss of adhesive strength for laminating the film. On the other hand, if the moisture content is high, the adhesive layer contains a large amount of water, which prevents water from escaping after lamination, resulting in poor appearance (internal air bubbles). For these reasons, the moisture content of the adhesive after drying is preferably 1 to 8% by mass. In particular, when drying is performed in a thermostatic oven, the moisture content of the adhesive after drying is preferably 1.5 to 3.5% by mass, more preferably 2.0 to 3.0% by mass, and even more preferably 2.5% by mass. When drying is performed in an infrared dryer, the moisture content of the adhesive after drying is preferably 2.0 to 6.0% by mass, and more preferably 2.0 to 4.0% by mass. The moisture content of the adhesive is measured by measuring the weight difference of the recovered adhesive-backed film before and after drying. Specifically, it is expressed as follows: moisture content of adhesive (%) = (mass of adhesive-backed film before drying - mass of adhesive-backed film after drying) / (mass of adhesive-backed film before drying) x 100. Next, the waterstop film 12 is bonded to at least one surface of the base fabric 11 with the adhesive layer 14 side (the side where the adhesive is applied) as the bonding surface, and the waterstop film 12 is bonded to the base fabric 11 by heating and pressing (step of bonding the surface layer 13 and the base fabric 11) (temporary bonding state). Next, the curing agent is cured by a curing acceleration reaction (a process for curing the adhesive) under conditions such as 30 to 40 hours (e.g., 36 hours at 23°C) when the curing temperature is room temperature of 18 to 28°C, or 20 to 30 hours (e.g., 24 hours at 50°C) when the curing temperature is 45 to 55°C, thereby firmly bonding the base fabric 11 and the water-stop film 12. The curing atmosphere can be air. This results in a fastener tape 10 with waterproof properties. The adhesive can also be applied to the base fabric 11 side.

[0018] (2. Adhesive Layer) The adhesive layer 14 is formed from a cured product of an adhesive containing aqueous polyurethane (polyurethane and water as a dispersion medium) produced by the acetone method. The adhesive is preferably a two-component adhesive that cures by mixing at least an aqueous polyurethane having hydroxy groups produced by the acetone method as a base component and an isocyanate compound as a curing agent. In aqueous polyurethane, fine particles of polyurethane are typically dispersed in water, and are provided in the form of, for example, a polyurethane emulsion or polyurethane dispersion. Here, "aqueous" means that water is used as a dispersion medium.

[0019] Aqueous polyurethanes produced by the acetone method are a type of self-emulsifying polyurethane, and are provided in a state in which polyurethane particles are dispersed in water due to the introduction of hydrophilic groups. In the acetone method, polyurethane is polymerized in an acetone solvent, and then deacetone is removed after dispersion in water. Because molecular weight control in an acetone solvent is relatively easy, it is believed that polyurethanes with high molecular weight uniformity can be obtained. Furthermore, it is believed that high molecular weight uniformity contributes to improved adhesive strength and reciprocating opening and closing durability. In one embodiment, aqueous polyurethanes produced by the acetone method have a polydispersity (Mw / Mn), which is the ratio of weight-average molecular weight (Mw) to number-average molecular weight (Mn), of 2.0 or less. The polydispersity (Mw / Mn) of aqueous polyurethanes produced by the acetone method is preferably 1.8 or less, and more preferably 1.6 or less. Since there is no particular lower limit set for the polydispersity (Mw / Mn) of aqueous polyurethanes produced by the acetone method, it is ideal to have a polydispersity of 1.0, but from the viewpoints of ease of production and storage stability, it is preferably 1.2 to 2.0, and more preferably 1.4 to 1.8. The weight-average molecular weight (Mw) of aqueous polyurethanes produced by the acetone method is preferably 2,000 to 6,000, and more preferably 3,000 to 5,000, from the viewpoints of ensuring adhesiveness (tackiness) after coating and film formation and increasing the initial adhesion strength of the adhesive layer to the fastener tape.

[0020] Any aqueous polyurethane known to those skilled in the art can be used for the acetone method, but polyether-based polyurethanes, polyester-based polyurethanes, polycarbonate-based polyurethanes, or polycaprolactone-based polyurethanes having hydrophilic groups are preferred. Among these, polycarbonate-based polyurethanes having hydrophilic groups are more preferred due to their hydrolysis resistance, heat resistance, oil resistance, and abrasion resistance. Examples of hydrophilic groups include cationic, anionic, and nonionic hydrophilic groups, which can be used alone or in combination. Examples of cationic groups include amino groups. Examples of anionic hydrophilic groups include carboxyl groups, phosphonic acid groups, and sulfonic acid groups. Examples of nonionic hydrophilic groups include polyalkylene oxide groups (e.g., polyethylene oxide groups) and hydroxy groups. Among the hydrophilic groups, at least a hydroxy group is preferred because it promotes the curing reaction with the curing agent. Furthermore, when the polyurethane has an anionic hydrophilic group such as a carboxyl group, it is desirable to neutralize it with a base such as triethylamine, ammonia, or 2-amino-2-methylpropanol in order to enhance the hydrophilicity of the polyurethane.

[0021] The isocyanate compound used as the curing agent may contain an aliphatic isocyanate, an alicyclic isocyanate, an aromatic isocyanate, or a combination of two or more of these. The isocyanate may be selected from, for example, a dimer, a trimer, an isocyanate derivative, an isocyanate prepolymer, or a blocked isocyanate. While aromatic isocyanates tend to yellow, aliphatic isocyanates, alicyclic isocyanates, or combinations thereof have excellent discoloration resistance and a long pot life (also known as pot life, the time until the viscosity or condition of the adhesive becomes unsuitable for use after mixing with a curing agent, catalyst, etc.). Therefore, it is preferable to use an aliphatic isocyanate, an alicyclic isocyanate, or a combination thereof. Examples of aliphatic isocyanates include ethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, dodecamethylene diisocyanate, 2,2,4-trimethylhexane diisocyanate, lysine diisocyanate, 2,6-diisocyanatomethyl caproate, isophorone diisocyanate, 1,4-cyclohexane diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, bis(isocyanatomethyl)cyclohexane, cyclohexylene diisocyanate, and methylcyclohexylene diisocyanate. These may be provided as a monomer or a polymer.

[0022] A thickener can be added to the adhesive to facilitate application, etc. Any known water-soluble thickener can be used as the thickener, and examples thereof include natural polymers such as polysaccharides and gelatin, synthetic polymers such as hydrophobically modified ethoxylated urethane, polyoxyethylene and cross-linked poly(meth)acrylic acid, and inorganic minerals such as montmorillonite and silica.

[0023] During curing, aqueous polyurethane adhesives undergo solvent evaporation and a reaction between the base agent and curing agent occurs. The resulting adhesive layer 14 is primarily composed of crosslinked polyurethane formed by the curing reaction between the base agent and curing agent, and the solids of the thickener, if present. When forming the adhesive layer 14, the mixing ratio of the base agent and curing agent is preferably set to achieve the desired adhesive strength. Specifically, the base agent and curing agent are mixed so that the molar ratio (NCO / OH) of the hydroxyl groups (OH) of the aqueous polyurethane as the base agent to the isocyanate groups (NCO) of the isocyanate compound as the curing agent is 1.0 or higher, preferably 1.2 or higher, and even more preferably 1.4 or higher. Furthermore, from the viewpoint of preventing appearance abnormalities due to side reaction products, the NCO / OH ratio is preferably 3.0 or lower, more preferably 2.5 or lower, and even more preferably 2.0 or lower. Therefore, the NCO / OH ratio is, for example, preferably 1.0 to 3.0, more preferably 1.2 to 2.5, and even more preferably 1.4 to 2.0.

[0024] To enhance the adhesive strength between the water-stop film and the base fabric, the amount of hydroxyl groups (OH) in the aqueous polyurethane as the main component is preferably 1.0% by mass or more, more preferably 1.3% by mass or more, and even more preferably 1.6% by mass or more, expressed as a mass concentration relative to the polyurethane solids in the aqueous polyurethane as the main component. On the other hand, considering the balance between the strength and flexibility of the adhesive layer, the amount of hydroxyl groups (OH) in the aqueous polyurethane as the main component is preferably 3.0% by mass or less, more preferably 2.5% by mass or less, and even more preferably 2.0% by mass or less, expressed as a mass concentration relative to the polyurethane solids in the aqueous polyurethane as the main component. Therefore, the amount of hydroxyl groups (OH) in the aqueous polyurethane as the main component is preferably 1.0 to 3.0% by mass, more preferably 1.3 to 2.5% by mass, and even more preferably 1.6 to 2.0% by mass or less, expressed as a mass concentration relative to the polyurethane solids in the aqueous polyurethane as the main component.

[0025] In this specification, the amount of hydroxy groups (OH) in an aqueous polyurethane is measured by the following procedure. 2-naphthoxyacetic acid chloride is used as a UV labeling agent, and the aqueous polyurethane is reacted with tetrahydrofuran (THF) in the presence of pyridine for approximately 24 hours. Next, gel permeation chromatography (GPC) measurement is performed, and the amount of hydroxy groups (OH) is measured by a calibration curve method from the peak areas at UV absorption wavelengths specific to the labeling agent (near 240 nm, near 270 nm, and near 330 nm). In this specification, the amount of isocyanate groups (NCO) in an isocyanate compound is measured by adding excess di-n-butylamine to the isocyanate compound to react with it, and then neutralizing and titrating the remaining di-n-butylamine with hydrochloric acid.

[0026] The thickness of the adhesive layer 14 is preferably 50 μm or more, more preferably 70 μm or more, and even more preferably 90 μm or more, for reasons of durability against reciprocating opening and closing. On the other hand, if the thickness of the adhesive layer 14 is too thick, the slider will slide against the adhesive layer 14 when the slide fastener is opened and closed, impairing slidability. Therefore, the thickness of the adhesive layer 14 is preferably 150 μm or less, more preferably 120 μm or less, and even more preferably 100 μm or less. Therefore, the thickness of the adhesive layer 14 is preferably 50 μm or more and 150 μm or less, more preferably 70 μm or more and 120 μm or less, and even more preferably 90 μm or more and 100 μm or less.

[0027] In this specification, the thickness of the adhesive layer 14 is measured by the following method. The overall thickness of the fastener tape is measured at three locations near the center in the width direction at intervals of 8 to 10 cm in the longitudinal direction of the fastener tape. A digital thickness gauge is used to measure the thickness. The average value of the thicknesses obtained at the three locations is calculated. Next, the thicknesses of the base fabric and the skin layer from which the adhesive layer has been removed are measured at the same locations as those where the overall thickness of the fastener tape was measured, using the same method, and the average values ​​of the thicknesses of the base fabric and the skin layer are calculated. The thickness of the adhesive layer is then determined by subtracting the sum of the average thicknesses of the base fabric and the skin layer from the average thickness of the overall fastener tape.

[0028] (3. Surface Layer) The surface layer 13 can be formed as a film using aqueous polyurethane produced by the acetone method as a raw material. This film can be obtained by heating and drying a liquid in which aqueous polyurethane, typically particulate polyurethane, is dispersed in water. The drying conditions are not limited, but can be, for example, 3 to 10 minutes in a hot air drying oven at 50 to 90°C.

[0029] Aqueous polyurethane produced by the acetone method is a type of self-emulsifying polyurethane, and is provided in a state where polyurethane particles are dispersed in water due to the introduction of hydrophilic groups. As mentioned above, aqueous polyurethane produced by the acetone method is thought to have high molecular weight uniformity, and this high molecular weight uniformity is presumed to contribute to improved adhesive strength and reciprocating opening and closing durability.

[0030] Any aqueous polyurethane known to those skilled in the art can be used for the acetone method, but polyether-based polyurethanes, polyester-based polyurethanes, polycarbonate-based polyurethanes, or polycaprolactone-based polyurethanes having hydrophilic groups are preferred. Among these, polycarbonate-based polyurethanes having hydrophilic groups are more preferred due to their hydrolysis resistance, heat resistance, oil resistance, and abrasion resistance. Examples of hydrophilic groups include cationic, anionic, and nonionic hydrophilic groups, which can be used alone or in combination. Examples of cationic groups include amino groups. Examples of anionic hydrophilic groups include carboxyl groups, phosphonic acid groups, and sulfonic acid groups. Examples of nonionic hydrophilic groups include polyalkylene oxide groups (e.g., polyethylene oxide groups) and hydroxy groups. Among hydrophilic groups, anionic hydrophilic groups are preferred. Furthermore, when the polyurethane has an anionic hydrophilic group such as a carboxyl group, it is desirable to neutralize it with a base such as triethylamine, ammonia, 2-amino-2-methylpropanol, or 2-dimethylaminoethanol in order to enhance the hydrophilicity of the polyurethane.

[0031] For example, aqueous polyurethanes with a weight-average molecular weight in the range of 7,000 to 32,000 can be suitably used. Furthermore, because a film with excellent strength can be obtained even with short-term heat drying, it is preferable to use a mixture of a low-molecular-weight aqueous polyurethane with a weight-average molecular weight of 7,000 to 15,000 and a high-molecular-weight aqueous polyurethane with a weight-average molecular weight of 18,000 to 32,000. The mass blending ratio of low-molecular-weight aqueous polyurethane to high-molecular-weight aqueous polyurethane is preferably low-molecular-weight aqueous polyurethane:high-molecular-weight aqueous polyurethane = 5:95 to 20:80, more preferably 10:90 to 15:85, because this tends to improve film strength. The weight-average molecular weight of the aqueous polyurethane can be measured by gel permeation chromatography (GPC) (molecular-weight distribution analysis).

[0032] A thickener can be added to the film forming the skin layer 13 to facilitate molding process, etc. Any known water-soluble thickener can be used as the thickener, and examples thereof include natural polymers such as polysaccharides and gelatin, synthetic polymers such as hydrophobically modified ethoxylated urethane, polyoxyethylene and cross-linked poly(meth)acrylic acid, and inorganic minerals such as montmorillonite and silica.

[0033] (4. Embodiment of Slide Fastener) Figures 2 to 4 show an example of a waterproof slide fastener 20 equipped with the fastener tape of the present invention. Figure 2 is a plan view of the entire waterproof slide fastener 20, Figure 3 is a cross-sectional view showing the state in which the fastener element rows 21 are interlocked within the slider 22, and Figure 4 is a perspective cross-sectional view of a portion of the waterproof slide fastener 20. Linear coil-shaped fastener element rows 21 with core cords 23 inserted therein are sewn along the side edges of one surface of the base fabric 11 of each fastener tape 10 with double chain stitch thread 24. The coil-shaped fastener element rows 21 can be formed from monofilaments of synthetic resins such as polyamide and polyester. The waterstop films 12 of the pair of fastener tapes 10 can be bonded to the fabric of the article via an adhesive. Alternatively, the waterstop films 12 and the fabric can be welded by high frequency or sewn together. A slider is inserted between the left and right element rows, and the open / close state of the slide fastener can be controlled by sliding the slider. The sewing thread 24 may be treated to be water repellent.

[0034] The left and right waterstop films 12 are more likely to adhere to each other and waterproofing is improved by having the waterstop films 12 extend beyond the side edges of the base fabric 11 toward the meshing center line A of the element rows. If the side edges of the waterstop films 12 extend slightly beyond the meshing center line A of the element rows, the left and right waterstop films 12 will come into close contact with each other when the left and right element rows mesh, resulting in higher waterproofing.

[0035] When using the waterproof slide fastener 20 according to this embodiment, it is preferable to attach it to an article with the side to which the water-stop film 12 is attached facing outward and the fastener element row 21 facing inward. The pull tab 25 of the slider 22 can be attached to the outer surface. Also, as shown in Figure 2, an upper stop 26 can be provided, and although not shown, a lower stop, a separable bottom stop, etc. can also be attached.

[0036] 5 and 6 show partial schematic diagrams of a waterproof slide fastener according to another embodiment of the present invention. Specifically, Fig. 5 shows a part of a fastener stringer 27 constituting the waterproof slide fastener according to this another embodiment, and Fig. 6 is a virtual cross-sectional view showing a state in which left and right fastener elements 28 are interlocked inside a slider 29 in the slide fastener according to this another embodiment.

[0037] In this other embodiment, as shown in Figures 5 and 6, the fastener elements 28 are injection molded so as to sandwich the entire core 31 formed on the edge of the fastener tape 30 from the front and back. The slider 29 is shown by an imaginary line using a dashed dotted line. The fastener tape 30 is formed by attaching a water-stop film 33 to the outer surface of the base fabric 32. Then, as shown in Figure 6, when engaged, the tip of the fastener element 28 on one side (the end facing the fastener tape on the other side) comes into close contact with the fastener tape 30 on the other side, thereby achieving waterproofing.

[0038] Waterproof slide fasteners can be used not only for special applications such as protective clothing such as space suits, chemical protective suits, diving suits, and survival suits, and covers for transport containers and tents, but also for opening and closing devices for everyday items such as clothing (especially rain gear), bags, shoes, and miscellaneous goods.

[0039] To better understand the present invention and its advantages, the following examples are provided, but the present invention is not limited to these examples.

[0040] (1. Materials Used) The materials used in each test example are as follows. (A) Water-based polyurethanes (all produced by the acetone method) [A-1] IMPRANIL (registered trademark) DLC-F: manufactured by Covestro, polycarbonate-based anionic polyurethane aqueous dispersion (solid content = approximately 40% by mass, weight average molecular weight = 25,000), having carboxyl groups as anionic hydrophilic groups. [A-2] Bayhydrol (registered trademark) UH2648 / 1: manufactured by Covestro, polyester-polycarbonate-based anionic polyurethane aqueous dispersion (solid content = approximately 35% by mass, weight average molecular weight = 11,000), having carboxyl groups as anionic hydrophilic groups. [A-3] Bayhydrol (registered trademark) U2757: manufactured by Covestro, a hydroxyl group functional polycarbonate-based polyurethane aqueous dispersion (solid content = approximately 53% by mass, OH group amount = content of approximately 1.0% by mass, weight average molecular weight = 4,000, polydispersity (Mw / Mn) = 1.6) (B) Isocyanate compound (curing agent) Bayhydur (registered trademark) XP 2547: manufactured by Covestro, a mixture of hexamethylene-1,6-diisocyanate homopolymer (80% by mass) and HDI (hexamethylene diisocyanate)-based hydrophilic aliphatic polyisocyanate (20% by mass) (NCO group amount = content of 22.5% by mass) (C) Thickener Rheovis® PU1341: Hydrophobically modified ethoxylated urethane (HEUR) from BASF

[0041] (2. Preparation of Fastener Tape) Each fastener tape was prepared using the above materials according to the following procedure. The materials listed in the "Skin Layer" column of Table 1 were mixed in the compounding ratios listed in Table 1 according to the test number and applied to a release film. The mixture was then heated and dried in a thermostatic chamber for 5 minutes at 90°C in air, resulting in a skin layer film with a thickness of 35 to 45 μm. Next, the materials listed in the "Adhesive Layer" column of Table 1 (two-component adhesive) were mixed in the compounding ratios listed in Table 1 according to the test number and applied to the surface of the skin layer film. The mixture was then heated and dried in a thermostatic chamber for 5 minutes at 90°C in air. The moisture content of the adhesive after drying was measured using the method described above and found to be 1.8% by mass. A fastener tape made of a base fabric woven with polyester yarn was then attached thereto using a rubber roller (Shore hardness 50 to 95°) at a pressure of 4 MPa. A curing acceleration reaction was then carried out in a thermostatic chamber for 24 hours at 50°C under the same conditions as above. In this way, a fastener tape with a waterproof film attached was produced. The thickness of the adhesive layer of each fastener tape sample was measured according to the method described above. The results are shown in Table 1.

[0042]

[0043] (3. Performance Evaluation)

[0044] [3-1. Acetone Resistance Test A] The fastener tapes prepared above corresponding to each test number were immersed in acetone (at room temperature) for 1 minute. The fastener tapes were then pulled out and evaluated for peeling of the water-stop film. After the test, the evaluation was rated as "D" if a portion with a peeling length of more than 1 mm and not more than 1.5 mm was observed in the longitudinal direction of the fastener tape; "C" if a portion with a peeling length of more than 0.5 mm to not more than 1.5 mm was observed in the longitudinal direction of the fastener tape; "B" if there was almost no film peeling but some areas that could be evaluated as abnormal were observed; and "A" if no abnormalities were observed. The results are shown in Table 2.

[0045] [3-2. Acetone Resistance Test B] Waterproof slide fasteners with MH-class chain widths as shown in Figure 2 were assembled using the fastener tapes corresponding to the test numbers prepared above, and then immersed in acetone (at room temperature) for 10 seconds. Five minutes after the waterproof slide fastener was pulled up, the slider was slid open and closed 10 times to conduct a reciprocating opening and closing durability test in accordance with JIS S 3015 (2019). After the test, the appearance of the film forming the skin layer was visually inspected for any abnormalities (peeling of the skin film). The evaluation criteria were the same as those for Acetone Resistance Test A. The results are shown in Table 2.

[0046] [3-3. Reciprocating Opening and Closing Durability Test] Waterproof slide fasteners with MH-class chain widths as shown in Figure 2 were assembled using the fastener tapes corresponding to the test numbers prepared above. The fasteners were then slid open and closed 500, 1000, 1500, and 2000 times in a room-temperature, normal-humidity environment at a temperature of 20°C and a relative humidity of 65%, and a reciprocating open-closing durability test was conducted in accordance with JIS S 3015 (2019). Furthermore, a reciprocating open-closing durability test of 100 cycles was conducted in a high-temperature, high-humidity environment at a temperature of 70°C and a relative humidity of 95%. After the test, the appearance of the film forming the skin layer was visually inspected for any abnormalities (peeling of the skin film). The slider travel distance per slider slide was 50 mm. The evaluation criteria were the same as those for the acetone resistance test A. The results are shown in Table 2.

[0047] (4. Evaluation of Adhesive Processability) [4-1. Thixotropy] The thixotropy of the two-component adhesives used in the adhesive layers of the fastener tapes corresponding to each test number was evaluated using the following method. The adhesive was applied to a thickness of approximately 230 μm over a length of 30 cm on release paper conveyed at a constant speed using a coating machine in an air atmosphere at a constant temperature. In this case, if the material is highly thixotropic, the liquid will become a gel with no fluidity shortly after application, resulting in poor continuous application. The evaluation criteria were "good" if continuous, even application was possible, and "poor" if intermittent uncoated areas were observed. The results are shown in Table 2.

[0048] [4-2. Leveling Properties] The leveling properties of the two-component adhesives used in the adhesive layers of the fastener tapes corresponding to each test number were evaluated using the following method. The adhesive was coated to a thickness of approximately 230 μm onto release paper that was conveyed at a constant speed using a coating machine in an air atmosphere at a constant temperature. After coating, the adhesive was dried for 5 minutes at 90°C to obtain an adhesive layer. The resulting release paper with the adhesive layer was cut into a 30 cm x 30 cm square, and the thickness near the side edges of two adjacent sides (vertical and horizontal) was measured at three locations (six locations in total) approximately 9 cm apart per side using a Mitutoyo Corporation Model 547-401A digital thickness gauge (accuracy 1 μm). The evaluation criteria were as follows. The results are shown in Table 2. Good: The difference between the maximum and minimum thickness values ​​at six locations is less than 3 μm. Passable: The difference between the maximum and minimum thickness values ​​at six locations is 3 μm or more and less than 7 μm. Unacceptable: The difference between the maximum and minimum thickness values ​​at six locations is 7 μm or more.

[0049] [4-3. Foaming after drying] The foaming properties of the fastener tapes corresponding to each test number prepared above were evaluated by the following method. The surface of the obtained adhesive layer was visually inspected to confirm the foaming state. The evaluation criteria are as follows. The results are shown in Table 2. Good: No foaming-related lifting was observed in the film of the surface layer. Poor: Foaming-related lifting was observed in one or more places in the film of the surface layer.

[0050]

[0051] (Discussion) From the results of various tests on the fastener tapes corresponding to each test number, it was confirmed that the aqueous polyurethane produced by the acetone method can provide excellent adhesion between the water-stop film and the base fabric constituting the fastener tape, and also has excellent chemical resistance. Furthermore, it was confirmed that the preferred embodiments (test numbers 3 and 4) exhibit even better chemical resistance, and also exhibit excellent reciprocating opening and closing durability when applied to a slide fastener.

[0052] REFERENCE SIGNS LIST 10 zipper tape 11 base fabric 12 water-stop film 13 surface layer 14 adhesive layer 20 waterproof slide fastener 21 element row 22 slider 23 core string 24 sewing thread 25 pull tab 26 top stop 27 zipper stringer 28 zipper element 29 slider 30 zipper tape 31 core 32 base fabric 33 water-stop film

Claims

1. A fastener tape (10) comprising a base fabric (11, 32) and a water-stop film (12, 33) attached to at least one surface of the base fabric (11, 32), wherein the water-stop film (12, 33) has a laminated structure comprising a surface layer (13) made of a film using aqueous polyurethane produced by the acetone method as a raw material, and an adhesive layer (14) adjacent to the surface layer (13) and made of a cured product of an adhesive containing aqueous polyurethane produced by the acetone method.

2. The fastener tape according to claim 1, wherein the aqueous polyurethane that is the raw material of said film and the aqueous polyurethane contained in said adhesive both contain polycarbonate-based polyurethane.

3. The fastener tape according to claim 1 or 2, wherein the adhesive is a two-component adhesive that hardens by mixing at least an aqueous polyurethane having hydroxyl groups produced by the acetone method as the main component and an isocyanate compound as the hardener.

4. The fastener tape according to claim 3, wherein the aqueous polyurethane having hydroxyl groups produced by the acetone method as the main agent contains a polycarbonate-based polyurethane having hydroxyl groups.

5. The fastener tape according to claim 4, wherein the cured adhesive is a cured product obtained by at least mixing the base agent and the curing agent so that the molar ratio (NCO / OH) of the isocyanate groups (NCO) of the isocyanate compound serving as the curing agent to the hydroxyl groups (OH) of the aqueous polyurethane serving as the base agent is 1.4 or more.

6. The fastener tape according to any one of claims 1 to 5, wherein the aqueous polyurethane produced by the acetone method and used as a raw material for the film is a mixture of a low molecular weight aqueous polyurethane having a weight average molecular weight of 7,000 to 15,000 and a high molecular weight aqueous polyurethane having a weight average molecular weight of 18,000 to 32,000 in a mass blending ratio of low molecular weight aqueous polyurethane:high molecular weight aqueous polyurethane = 5:95 to 20:

80.

7. A slide fastener comprising the fastener tape according to any one of claims 1 to 6.

8. A method for manufacturing a fastener tape, comprising: a step of bonding a surface layer (13) made of a film using aqueous polyurethane produced by the acetone method as a raw material to a base fabric (11, 32) via an adhesive containing aqueous polyurethane produced by the acetone method; and a step of curing the adhesive sandwiched between the surface layer (13) and the base fabric (11, 32).

9. The method for producing a fastener tape according to claim 8, wherein the aqueous polyurethane that is the raw material of said film and the aqueous polyurethane contained in said adhesive both contain polycarbonate-based polyurethane.

10. A method for manufacturing a fastener tape according to claim 8 or 9, wherein the adhesive is a two-component adhesive that hardens by mixing at least an aqueous polyurethane having a hydroxyl group produced by the acetone method as the main component and an isocyanate compound as the hardener.

11. The method for producing a fastener tape according to claim 10, wherein the aqueous polyurethane having a hydroxy group produced by the acetone method as the main agent contains a polycarbonate-based polyurethane having a hydroxy group.

12. A method for producing a fastener tape as described in claim 11, wherein the cured adhesive is a cured product obtained by at least mixing the main component and the curing agent so that the molar ratio (NCO / OH) of the isocyanate group (NCO) of the isocyanate compound serving as the curing agent to the hydroxyl group (OH) of the aqueous polyurethane serving as the main component is 1.4 or more.

13. A method for producing a fastener tape according to any one of claims 8 to 12, wherein the aqueous polyurethane binder produced by the acetone method and used as a raw material for the film is a mixture of a low molecular weight aqueous polyurethane having a weight average molecular weight of 7,000 to 15,000 and a high molecular weight aqueous polyurethane having a weight average molecular weight of 18,000 to 32,000 in a mass blending ratio of low molecular weight aqueous polyurethane:high molecular weight aqueous polyurethane = 5:95 to 20:80.

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