Surface-fastened hook-and-loop fastener with excellent biodegradability

Abstract

Provided is a front-and-back engagement type hook-and-loop fastener comprising: a male molded hook-and-loop fastener layer which has a base and a plurality of male engaging elements protruding from the surface of the base, the base and the male engaging elements both containing polybutylene succinate; and a fiber layer which is formed from fibers comprising polybutylene succinate and which on one surface has a plurality of fiber loops that can engage with the male engaging elements, wherein the base of the male molded hook-and-loop fastener layer and the fibers of the fiber layer are directly bonded by fusion such that when disposed of after use the male molded hook-and-loop fastener on the front side and the fiber layer having loops on the back side quickly biodegrade, and between the molded male hook-and-loop fastener layer on the front side and the fiber layer having loops on the back side, there is no bonding agent layer, adhesive agent layer, or back coat layer which would interfere with biodegradability.

Description

Technical Field

[0001] The present invention comprises a molded surface fastener layer having male engaging elements and a fiber layer joined thereto and having fiber loops on the surface engageable with the male engaging elements, wherein the surface having the male engaging elements and the surface having the fiber loops are in a front-back relationship, and the front-back engaging type surface fastener is such that when discarded after use, both the molded surface fastener layer and the fiber layer are naturally decomposed in a short period of time, and as a result, no environmental damage is caused, and a binding or bundling tape for agriculture, forestry, and fisheries using such a front-back engaging type surface fastener.

Background Art

[0002] Conventionally, as a binding tape for binding rod-shaped bodies or linear bodies, or as a tying tape for tying the opening of a bag or the like, a loop surface fastener tape having loop-shaped engaging elements on the back surface of a male surface fastener tape having male engaging elements on the surface is widely used by being attached with an adhesive or an adhesive. Then, a binding tape or a tying tape in which a loop surface fastener tape is attached to the back surface of these male surface fastener tapes is wound around an object to be bound or an object to be tied, and the ends of the tape are overlapped with each other to engage the male engaging elements on the surface and the loop-shaped engaging elements on the back surface, so that binding and tightening can be easily performed. Such tapes are widely used particularly as tying tapes or binding tapes for agriculture, forestry, and fisheries.

[0003] In recent years, when plastic products are discarded in the natural world after use, they are not decomposed and accumulate in the natural world, causing environmental pollution. Therefore, products made of biodegradable resins that do not pollute the natural environment are required. Also in the field of binding tapes and tying tapes using surface fasteners, products used particularly in the fields of agriculture, forestry, and fisheries, civil engineering and construction, disposable products, etc. are required to have so-called biodegradability, that is, they decompose in a relatively short period of time when discarded in the natural environment after use.

[0004] Conventionally, as a commonly used hook-and-loop fastener, there is a male hook-and-loop fastener having hook-shaped or mushroom-shaped male engaging elements made of thick monofilaments on the surface of a fabric base fabric, or a loop hook-and-loop fastener having loop-shaped engaging elements made of multifilament yarns on the surface of a fabric base fabric. In the case of such a fabric hook-and-loop fastener, a backcoat adhesive layer (referred to as a backcoat layer) made of polyurethane or acrylic resin is provided on the back surface of the fabric base fabric so that the male engaging elements or loop-shaped engaging elements are not pulled out during engagement and disengagement from the surface of the fabric base fabric. Even if the fibers constituting such a fabric base fabric and engaging elements are biodegradable, since the backcoat layer has almost no biodegradability, the hook-and-loop fastener is difficult to biodegrade. Moreover, since the back surface of the fabric base fabric is covered with a non-biodegradable backcoat layer, biodegradation does not occur from the back surface, and the biodegradability of the fabric base fabric also takes a long time.

[0005] In order to solve the problem of biodegradability of such a fabric hook-and-loop fastener and make the entire hook-and-loop fastener meet the requirement of biodegradability, Patent Document 1 proposes a molded hook-and-loop fastener manufactured by injection molding, extrusion molding, etc. using a biodegradable resin mainly composed of polybutylene succinate or polyethylene adipate. Since such a molded hook-and-loop fastener is manufactured by simultaneously molding a base body and male engaging elements protruding from its surface, it is not necessary to provide a backcoat layer on the back surface, and the above-mentioned problem of biodegradability can be solved.

[0006] Since the molded hook-and-loop fastener made of polybutylene succinate, polyethylene adipate, etc. has biodegradability in this way, environmental pollution can be prevented. However, in reality, the decomposition rate of the molded hook-and-loop fastener in the natural environment is slow. For example, when it is discarded in the soil, these resin-made molded hook-and-loop fasteners still maintain their form even after one year, and do not necessarily meet the requirement of quickly decomposing to prevent environmental pollution as required by society.

[0007] In addition, since the loop surface fastener integrated on the back side of such a male molded surface fastener on the front side cannot be manufactured by molding like a male molded surface fastener, it has to be made of a fabric. This fabric loop surface fastener needs to be provided with a backcoat layer on its back side to prevent the loop-shaped engaging elements from being pulled out during engagement and disengagement. Furthermore, an adhesive or a pressure-sensitive adhesive is required to bond this backcoat layer to the back side of the male molded surface fastener. Since this backcoat layer and the adhesive layer or pressure-sensitive adhesive layer for bonding do not have biodegradability, a biodegradable front-back engaging type surface fastener that can be used for binding tapes or tying tapes in the agricultural, forestry, and fisheries industries cannot be obtained.

[0008] Also, even if a biodegradable fiber surface fastener without a backcoat layer, an adhesive layer, or a pressure-sensitive adhesive layer is obtained as the loop surface fastener bonded to the back side of the male molded surface fastener, the male molded surface fastener on the surface layer side has a slow biodegradation rate. Eventually, the front-back engaging type surface fastener is dominated by the biodegradation rate of the male molded surface fastener on the surface side and requires a long time for biodegradation.

Prior Art Documents

Patent Documents

[0009]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0010] The object of the present invention is to provide a front-back engaging type surface fastener in which when discarded after use, both the male-molded surface fastener on the front surface side and the fiber layer having loops on the back surface side are rapidly biodegradable, and further, there is no adhesive layer, adhesive layer, or backcoat layer that hinders biodegradability between the male-molded surface fastener layer on the front surface side and the fiber layer having loops on the back surface side. And preferably, the male-molded surface fastener on the front surface side provides a front-back engaging type surface fastener in which the male engaging element does not break or crack in the substrate during molding, and a high engaging force can be obtained during use.

Means for Solving the Problems

[0011] That is, the present invention has a substrate and a plurality of male engaging elements protruding from the surface thereof, and both the substrate and the male engaging elements contain polybutylene succinate (A), and satisfy the following condition (1). A male-molded surface fastener layer (I), and a fiber layer (II) formed from fibers made of polybutylene succinate (A), having a plurality of fiber loops on one side thereof that can engage with the male engaging elements, and further satisfying the following condition (2). It is a biodegradable front-back engaging type surface fastener in which the fiber layer (II) is directly joined to the substrate of the male-molded surface fastener layer (I) by fusion bonding. (1) The plurality of male engaging elements are arranged in a row, and each male engaging element has a shape that rises from the substrate surface, bends in the row direction from the middle thereof, and the tip thereof faces the direction approaching the substrate surface, and the height is 1.2 mm or less, or each male engaging element has a bifurcated shape that rises from the substrate surface and is divided before and after in the row direction in the middle, and the height is 0.6 mm or less. (2) The surface on which the fiber loops of the fiber layer (II) are present and the surface on which the male engaging elements of the male-molded surface fastener layer (I) protrude are in a front-back relationship.

[0012] And preferably in the present invention, the fiber layer (II) is a nonwoven fabric layer, and this nonwoven fabric layer is composed of a fine fiber layer (II-1) made of fibers with a fineness of 1.0 to 4.0 dtex and a thick fiber layer (II-2) made of fibers with a fineness of 6 to 20 dtex. The total basis weight of the fine fiber layer (II-1) and the thick fiber layer (II-2) is 20 to 200 g / m 2 And further, it is a case where the fine fiber layer (II-1) is joined to the back surface of the substrate so as to be on the side of the male mold forming surface fastener layer (I). Also, when such a fiber layer (II) is a nonwoven fabric layer, preferably the fibers constituting the thick fiber layer (II-2) have crimps, and the thick fiber layer (II-2) and the fine fiber layer (II-1) are integrated as a nonwoven fabric layer (II) by entanglement.

[0013] Also in the present invention, preferably the fiber layer (II) is a layer made of a tricot fabric formed from a multifilament yarn in which filaments made of polybutylene succinate are gathered. And in such a case, preferably the breaking elongation of the polybutylene succinate multifilament yarn constituting such a tricot fabric is 50 to 100%.

[0014] Furthermore, in the present invention, preferably, the fiber layer (II) is partially melted and formed into a film by thermocompression bonding, and the fiber layer (II) is directly joined to the back surface of the substrate at the melted and formed portion. Also, it is a case where the row of male engaging elements is formed on a ridge rising from the substrate. And preferably, starch (B) is added to the polybutylene succinate (A) forming the male - type molded surface fastener layer (I), where the polybutylene succinate (A) is the continuous phase and the starch (B) is the dispersed phase, and the starch (B) contains modified starch and 45 mass% or more of the starch (B) is amylose - based starch, and polyvinyl alcohol (C) is mixed in the above - mentioned dispersed phase, and the mass ratio of the polybutylene succinate (A) to the total mass of the polybutylene succinate (A), starch (B), and polyvinyl alcohol (C) constituting the male - type molded surface fastener layer (I) is 45 - 90%.

[0015] Furthermore, in the present invention, preferably, the modified starch is an etherified starch containing a hydroxyalkyl group, there may be a case where clay is mixed in the dispersed phase, the dispersed phase contains 3 - 30% water based on the mass of (B), there may be a case where a saturated fatty acid or its metal salt is added to the dispersed phase, and there may be a case where fine powder of cellulose is added to the continuous phase.

[0016] And the present invention is a tape composed of these biodegradable front - back engaging type surface fasteners, in which a row of engaging elements exists parallel to the tape length direction, and it is an invention of a tying or bundling tape for the agricultural, forestry, and fishery industries.

Effects of the Invention

[0017] In the front - back engaging type surface fastener of the present invention, the male - type engaging elements of the male - type molded surface fastener layer (I) forming the surface side are smaller than those of a normal molded surface fastener, thereby accelerating the biodegradation rate. And because such small male - type engaging elements are arranged in a row, a strong engaging force required for a bundling tape or a tying tape can be obtained. More preferably, starch is mixed in the polybutylene succinate, which is a biodegradable resin forming the male - type molded surface fastener, and this starch further accelerates the biodegradation rate of the polybutylene succinate.

[0018] And the fiber layer (II) having fiber loops joined to such a male - shaped molding surface fastener layer (I) is a fiber - made layer composed of polybutylene succinate, which is a biodegradable resin the same as the male - shaped molding surface fastener on the surface side. Moreover, the surface on which the fiber loops exist is directly joined to the male - shaped molding surface fastener layer (I) made of polybutylene succinate so that it has a front - back relationship with the surface on which the male engaging elements exist. As a result, both the male - shaped molding surface fastener layer (I) and the fiber layer (II) can be easily biodegraded. Preferably, such a fiber layer (II) made of polybutylene succinate is superposed on the back surface of the male - shaped molding surface fastener layer (I) such that the surface on which the male engaging elements exist and the surface on which the fiber loops exist are back - to - back, and they are partially thermocompression - bonded. Thereby, joining to the male - shaped molding surface fastener layer (I), maintaining the shape of the fiber layer (II), and pull - out resistance of the fiber loops engageable with the male engaging elements from the fiber layer are simultaneously obtained.

[0019] Moreover, there is no adhesive or the like that hinders biodegradability at all, and strong joining with the same resin with excellent joining properties has been achieved. And since the polybutylene succinate forming the fiber layer (II) does not substantially contain starch, the strength of the fiber is high. As a result, a high engaging force is obtained. Moreover, since the fiber layer (II) is formed of fibers, it does not require a long time for biodegradation like the male - shaped molding surface fastener layer (I). Therefore, there is no significant difference in the time required for decomposition between the fiber layer (II) and the male - shaped molding surface fastener layer (I) on the surface side, which is added with starch to increase the biodegradation rate. Further, when joined such that the surface on which the male engaging elements exist and the surface on which the fiber loops exist are back - to - back, the back surface of the male - shaped molding surface fastener layer (I) is preferably covered with the fiber layer (II). However, when discarded in nature, bacteria that decompose the biodegradable resin can easily pass through the fiber layer (II), and biodegradation also proceeds from the back - surface side of the male - shaped molding surface fastener layer (I), and the time required for decomposition is shortened.

[0020] Furthermore, in the present invention, when the molding material of the male molded surface fastener layer (I) is a resin mixture having polybutylene succinate (A) as the continuous phase and starch (B) as the dispersed phase, or when polyvinyl alcohol (C) is mixed in the dispersed phase, or when the starch (B) contains modified starch and 45% by mass or more of the starch (B) is amylose-based starch, the decomposition rate of the resin mixture becomes even faster compared to the case where only polybutylene succinate or only starch is added to polybutylene succinate. Therefore, when the male molded surface fastener layer (I) is discarded in nature after use, decomposition occurs promptly and it returns to nature, further preventing environmental pollution and environmental destruction.

[0021] Furthermore, the male molded surface fastener layer (I) used in the present invention is preferably a male molded surface fastener layer (I) obtained by a so-called draw molding method, in which the resin melted on the mold surface is made to flow in a sheet shape, and the melted resin material is press-fitted into the cavity of the male engaging element shape formed on the mold surface, and after cooling, the male engaging element is pulled out from the cavity and the sheet is peeled off from the mold surface to form a male molded surface fastener having the male engaging element on the surface. In this case, when the molding resin is a mixture of polybutylene succinate and starch, there may be a phenomenon that the male engaging element breaks or a crack occurs during the pulling out from the cavity, or a crack is likely to occur in the substrate when the male molded surface fastener layer (I) is peeled off from the mold. When the male engaging element breaks or a crack occurs in the substrate, the commercial value of the male molded surface fastener layer (I) is greatly reduced and the engaging force is also reduced. However, by using the resin mixture containing starch and polyvinyl alcohol as described above, the problems that the male engaging element is likely to break during the pulling out of the male engaging element from the cavity to form the surface fastener and that a crack is likely to occur when the substrate sheet of the surface fastener is peeled off from the mold surface can be solved.

Brief Description of the Drawings

[0022]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Mode for Carrying Out the Invention

[0023] Hereinafter, the present invention will be described in detail with reference to the drawings. FIG. 1 is a perspective view schematically showing a partially enlarged view of an example of the biodegradable front-back engaging type surface fastener of the present invention. A plurality (a large number) of male engaging elements (2) stand up from the surface of the base (1). The male forming surface fastener layer (I) is constituted by these base (1) and male engaging elements (2). And, as shown in FIG. 1, the male engaging elements (2) are arranged in a row in the same direction as the bending direction (the male engaging elements in the front row shown in FIG. 1 are bent in the direction of Q shown in FIG. 1), and further, the bending direction is reversed (that is, the direction of P shown in FIG. 1) in units of one row or multiple rows (in FIG. 1, in units of one row). And, the male engaging element (2) becomes thinner from the root to the tip, and gradually bends halfway, and the tip is directed in the direction approaching the substrate (1) slightly (hereinafter, this shape may be referred to as a wave shape). And, a fiber layer (5) is joined and integrated on the back surface of the male forming surface fastener layer, and is joined so that the surface where the male engaging element exists and the surface where the fiber loop exists are back to back.

[0024] FIG. 2 is a perspective view schematically showing an enlarged part of another example of the biodegradable front-back engaging type surface fastener of the present invention, in which a number of male engaging elements (3) stand up from the surface of the base (1). The male forming surface fastener layer (I) is constituted by the base (1) and the male engaging elements (2). Also in this case, the plurality of male engaging elements (3) are arranged in a row, and each male engaging element (3) has a bifurcated shape divided before and after in the column direction (direction of Q shown in FIG. 2) in the middle thereof, and the bifurcated tip portions are directed in a direction slightly approaching the base (1) (hereinafter, this shape may be referred to as a Y shape). And on the back surface of the male forming surface fastener layer, in the same manner as in the case of FIG. 1, the fiber layer (5) is joined and integrated so that the surface where the male engaging elements are present and the surface where the fiber loops are present face each other.

[0025] Such a corrugated or Y-shaped male forming surface fastener is obtained by covering the surface of a metal roll having a number of corrugated or Y-shaped cavities on the surface with a molten resin in a sheet form and at the same time pressing the same molten resin into the cavities, and then peeling the resin sheet from the metal roll surface and pulling it out from the cavities after the resin has solidified.

[0026] As a method of manufacturing the male forming surface fastener layer (I) by pulling it out from the cavity of the mold, in addition to the method of pulling it out from a corrugated or Y-shaped cavity as in the present invention to immediately manufacture a corrugated or Y-shaped engaging element, there is also a method of pulling out a rod-shaped body extending vertically from a cavity extending straight vertically from the mold surface, and then heating and bending the top of the rod-shaped body to manufacture a corrugated engaging element. In the case of this method, certainly, the possibility of breaking in the middle of the engaging element during pulling out is small, but on the other hand, a step of heating and bending the tip after pulling out from the cavity is required, and furthermore, the obtained male forming surface fastener has the male engaging elements not aligned and is inferior in terms of appearance compared to a metal roll having a number of Y-shaped cavities on the surface.

[0027] As described above, the resin forming the male - type molded - surface fastener layer (I) constituting the present invention contains polybutylene succinate (A) as an essential component, and preferably, starch (B) and polyvinyl alcohol (C) are further mixed with this essential component. And in the present invention, the fact that both the substrate of the male - type molded - surface fastener layer (I) and the male - type engaging element contain polybutylene succinate means that it is polybutylene succinate alone or a resin mixture containing 40% by mass or more of polybutylene succinate, preferably 45% by mass or more, more preferably 50% by mass or more, still more preferably 55% by mass or more, and even more preferably 65% by mass or more. Here, the resin mixture contains all the components constituting the male - type molded - surface fastener layer (I). It is preferable that polybutylene succinate is the component with the highest content among the components constituting the male - type molded - surface fastener layer (I).

[0028] Among these, polybutylene succinate (A) is an aliphatic polyester - based resin synthesized from 1,4 - butanediol and succinic acid, and is widely commercially available as a biodegradable resin. In the present invention, those can be used. Of course, a small amount of monomers other than the above raw materials may be copolymerized, and various stabilizers, pigments, dyes, etc. may be added.

[0029] Examples of biodegradable resins include, in addition to polybutylene succinate, polylactic acid, polyethylene adipate, polycaprolactone, etc. However, in terms of affinity with starch and polyvinyl alcohol, moldability, etc., polybutylene succinate is used in the present invention. Of course, a small amount of biodegradable resins other than polybutylene succinate may be added.

[0030] Moreover, the starch (B) used as one of the preferred additive resins of the molding material of the present invention preferably contains modified starch. More preferably, the total amount of starch is modified starch. Examples of the modified starch include at least one selected from the group consisting of etherified starch, esterified starch, cationized starch, and crosslinked starch.

[0031] Examples of the starch include starch derived from cassava, corn, potato, sweet potato, tapioca, beans, arrowroot, wheat, rice, oats, etc. Among them, starch derived from corn or cassava is preferable, and starch derived from high amylose corn is more preferable. The starch may be single or a mixture of two or more. These starches are modified to obtain modified starch. Most of these starches have amylopectin as the main component, and only a small amount of starch has amylose as the main component. In order to satisfy the condition defined as an aspect of the present invention, that is, 45% by mass or more of the starch (B) is amylose-based starch, it is necessary to select a specific starch, that is, high amylose starch.

[0032] Among the modified starches, examples of the etherified starch include alkyl etherified starch represented by methyl etherified starch, carboxyalkyl etherified starch represented by carboxymethyl etherified starch, hydroxyalkyl etherified starch represented by etherified starch having a hydroxyalkyl group with 2 to 6 carbon atoms, etc. are preferred examples. Also, allyl etherified starch etc. can also be used.

[0033] Examples of the esterified starch include esterified starch having a structural unit derived from a carboxylic acid such as acetic acid, esterified starch having a structural unit derived from a dicarboxylic acid anhydride such as maleic anhydride, phthalic anhydride, octenyl succinic anhydride, etc., esterified starch having a structural unit derived from an inorganic acid such as nitric acid, phosphoric acid, etc., urea phosphate esterified starch, etc. Other examples include xanthic acid esterified starch, acetoacetic acid esterified starch, etc.

[0034] Examples of cationic starches include the reaction product of starch and 2 - diethylaminoethyl chloride, the reaction product of starch and 2,3 - epoxypropyltrimethylammonium chloride, and the like. Examples of crosslinked starches include formaldehyde - crosslinked starch, epichlorohydrin - crosslinked starch, phosphate - crosslinked starch, acrolein - crosslinked starch, and the like.

[0035] Among these modified starches, particularly preferred in the present invention is etherified starch having a hydroxyalkyl group with 2 to 6 carbon atoms. Among them, etherified starch containing a hydroxypropyl group modified by reacting starch with propylene oxide is most preferred for achieving the effects of the present invention.

[0036] In the present invention, it is preferable that 45% by mass or more of starch (B) is amylose - type starch. When the proportion of amylose - type starch is 45% by mass or more, when pulling out the engaging element from the cavity of the mold, it is well prevented that the engaging element breaks in the middle or that cracks occur in the base layer or the engaging element. More preferably, the proportion of amylose - type starch is 50% by mass or more, and even more preferably, the proportion of amylose - type starch is 55% by mass or more.

[0037] In the present invention, as described above, it is preferable that the total amount of starch (B) is modified starch. In that case, the mass ratio of the amylose - derived modified starch in the modified starch is referred to as the proportion of amylose - type starch in the present invention. In the present invention, it may also contain unmodified starch other than that. In such a case, the proportion of amylose - type starch referred to in the present invention means the proportion of the total mass of amylose derived from modified starch and amylose in unmodified starch in the total mass of modified starch and unmodified starch.

[0038] Therefore, high amylose modified starch may be used as the modified starch, low amylose unmodified starch may be used as the unmodified starch, or vice versa, and the total amount thereof may be adjusted so that the proportion of amylose is 45% by mass or more. Even when such unmodified starch is included, more preferably, the proportion of amylose-based starch is 50% by mass or more, and even more preferably, the proportion of amylose-based starch is 55% by mass or more.

[0039] Note that there are almost no starches in nature with an amylose-based starch content exceeding 90% by mass. Therefore, also in the present invention, the proportion of amylose-based starch is usually 90% by mass or less.

[0040] When the resin forming the male molded surface fastener layer (I) of the present invention contains starch (B), it is preferable that polyvinyl alcohol (C) is mixed as described above. As the polyvinyl alcohol, preferably, those having a saponification degree of 85 to 99.8 mol% are used, and particularly, completely saponified unmodified polyvinyl alcohol having a saponification degree of 99.0 to 99.8 mol% is more preferable because it can highly prevent breakage of the engaging element during drawing molding and tearing of the substrate sheet.

[0041] In the present invention, when starch (B) is added to polybutylene succinate (A), which is a raw material for forming the male molded surface fastener, it is preferable that polybutylene succinate (A) is the continuous phase and starch (B) is the dispersed phase. Further, when polyvinyl alcohol (C) is mixed in such a mixed system of polybutylene succinate (A) and starch (B), it is preferable that polyvinyl alcohol (C) is contained in the starch (B) layer because it can solve the problems caused by the addition of starch (B).

[0042] Since polybutylene succinate (A) forms the continuous phase and starch (B) forms the dispersed phase, it is possible to highly prevent the breakage of the engaging elements and the tearing of the substrate sheet during drawing. In order for polybutylene succinate (A) to form the continuous phase and starch (B) to form the dispersed phase, the proportion of polybutylene succinate (A) to the total mass of polybutylene succinate (A), starch (B), and polyvinyl alcohol (C) may be 45% by mass or more, preferably 50% by mass or more.

[0043] However, if the proportion of polybutylene succinate (A) is too high and the proportion of starch (B) is too low, the biodegradation rate will be slow, and when it is discarded in nature after use, it will take a long time to decompose and return to nature. By making the male engaging element of the forming surface fastener small, this problem can be significantly reduced, but it is preferably the case when starch (B) or polyvinyl alcohol (C) is added. The upper limit of the proportion of polybutylene succinate (A) to the total mass of polybutylene succinate (A), starch (B), and polyvinyl alcohol (C) is preferably 90% by mass. And as a more suitable value, the proportion of polybutylene succinate (A) is in the range of 45 - 90% by mass, more preferably 55 - 85% by mass, still more preferably 60 - 85% by mass, even more preferably 70 - 85% by mass of the above total amount. The content of starch (B) is preferably 10 - 90 parts by mass with respect to 100 parts by mass of polybutylene succinate (A). When it is 10 parts by mass or more, the biodegradability is further promoted. When it is 90 parts by mass or less, a higher engaging force can be obtained during use. From this perspective, it is more preferably 20 - 90 parts by mass, still more preferably 30 - 90 parts by mass, even more preferably 30 - 80 parts by mass, even more preferably 30 - 60 parts by mass, even more preferably 30 - 40 parts by mass.

[0044] In the present invention, the mass of polyvinyl alcohol (C) in the total mass of starch (B) and polyvinyl alcohol (C) is preferably 0.5 to 75% by mass. When it is 0.5% by mass or more, the breakage of the engaging element during the drawing forming can be prevented. When it is 75% by mass or less, the biodegradation rate becomes faster, and when it is discarded in the natural world after use, it decomposes in a short time and does not require time to return to the natural world. More preferably, it is in the range of 1 to 50% by mass.

[0045] In the present invention, in order to prevent the breakage of the engaging element and the tearing of the base sheet during the drawing forming, it is preferable that clay is mixed in the dispersed phase. Examples of the clay include synthetic or natural layered silicate clays such as montmorillonite, bentonite, beidellite, mica, hectorite, saponite, nontronite, sauconite, vermiculite, rectorite, magadite, kenyaite, stevensite, volkonskoite, etc., and those obtained by modifying these clays may also be used. The addition amount in the total amount of the components of the male forming surface fastener phase (I) of these clays is in the range of 0.1 to 5% by mass, more preferably 0.5 to 2% by mass.

[0046] Furthermore, in the present invention, in order to prevent the breakage of the engaging element and the tearing of the base sheet during the drawing forming, it is preferable that a saturated fatty acid or its metal salt is added to the dispersed phase. By adding such a saturated fatty acid or its metal salt, the slipperiness between starch molecules is improved, and as a result, the breakage of the engaging element and the tearing of the base sheet during the drawing forming can be prevented.

[0047] Specific saturated fatty acids or metal salts thereof to be added include fatty acids having 12 to 22 carbon atoms and their metal salts. For example, stearic acid, palmitic acid, lauric acid, myristic acid, linoleic acid, behenic acid, and sodium salts, calcium salts, potassium salts, etc. of these acids can be mentioned. The addition amount of these saturated fatty acids or their metal salts is in the range of 0.01 to 5% by mass based on the total amount of the resin constituting the dispersed phase. Also, the addition amount of the saturated fatty acid or its metal salt is in the range of 0.01 to 5% by mass based on the total amount of the male mold surface fastener layer (I).

[0048] In the present invention, it is preferable that the dispersed phase of the male mold surface fastener layer (I) contains 3 to 30% by mass of water with respect to the mass of starch (B) in order to prevent the breakage of the engaging elements during the drawing forming. More preferably, it contains 5 to 20% by mass, still more preferably 10 to 20% by mass, and even more preferably 11 to 18% by mass of water.

[0049] Furthermore, in the present invention, it is preferable that cellulose nano powder is added to the continuous phase or the dispersed phase in order to improve the biodegradation rate and prevent the male engaging elements and the substrate from cracking or having cracks. Specifically, it is preferable to add cellulose nano powder having a diameter of 3 to 30 nm and a length of 0.5 to 10 μm in an amount of 0.5 to 10% by mass with respect to the resin forming the male mold surface fastener layer (I). More preferably, it is 1 to 10% by mass, and still more preferably 2 to 8% by mass. The cellulose nano powder may be unmodified or modified.

[0050] Thus, the male - type molded surface fastener layer (I) constituting the present invention contains polybutylene succinate (A) as an essential component, starch (B) and polyvinyl alcohol (C) as suitable components. As a method of mixing these (A), (B) and (C), there are methods such as mixing them simultaneously when molding the male - type molded surface fastener, or blending these three components simultaneously prior to molding the male - type molded surface fastener and pelletizing them. Preferably, (B) and (C) are melt - mixed in advance, further adding clay, saturated fatty acid or its metal salt, moisture, etc. and pelletizing them, and then mixing and melting the pellet of (A) blended with this pellet and cellulose nanometer powder, and using this for molding the surface fastener. By using this method, a male - type molded surface fastener with high physical property values such as strength can be obtained.

[0051] At this time, it is also possible to melt - mix the pellet composed of (B) and (C) and the pellet of (A) and pelletize them once, and use this pellet for molding the surface fastener, or directly use the pellet composed of (B) and (C) and the pellet of (A) for molding the male - type molded surface fastener and use the method of mixing them simultaneously during molding.

[0052] As a specific method of melt - mixing and pelletizing (B) and (C) in advance, a method of sequentially performing step (a) of mixing (B) and (C) while heating and melting them, step (b) of extruding the melted mixture from a die, and step (c) of cooling and drying the extruded melt is preferably used.

[0053] Of these steps, step (a) is usually carried out using an extruder. In the extruder, shear stress is applied to each component by a screw, and (B) and (C) are homogeneously mixed while being heated by applying external heat to the barrel. As the extruder, a single-screw or twin-screw extruder can be used. When a twin-screw extruder is used, it can be either co-rotating or counter-rotating. As the screw diameter, for example, 20 to 150 mm is preferable, and as the ratio of the extruder length (L) to the screw diameter (D) (L / D ratio), 20 to 50 is respectively preferable. Also, as the rotational speed of the screw, 80 rpm or more is preferable, more preferably 100 rpm or more. Further, as the extrusion pressure, 5 bar (0.5 MPa) or more is preferable, more preferably 10 bar (1.0 MPa) or more. And (B), (C), and other components can each be directly introduced into the extruder, or a premixed product of these components by a mixer may be introduced into the extruder.

[0054] Step (a) is preferably carried out in the range of 120 to 180°C, more preferably at a temperature of 160 to 180°C. By using a temperature of 120°C or more, coarsening of the component (C) particles can be suppressed, and a proper particle size dispersion state can be obtained. By this step, component (B) has its starch particles crushed and gelatinized. Due to the crushing and gelatinization of these starch particles, physical property values such as the strength of the molded product are improved.

[0055] In step (a), water may be introduced at a relatively initial stage of the extruder. For example, water can be introduced when it is 100°C or less before reaching the above heating temperature, and further water can be introduced after reaching the above heating temperature. Component (B) is gelatinized (gelled) by a combination of moisture, heat, and shear stress. Also, by introducing water, component (C) can be dissolved, the resin mixture composed of (B) and (C) can be softened, and the modulus and brittleness can be reduced. As a result, physical properties such as the strength of the male molding surface fastener can be enhanced.

[0056] In step (a), the mixture of components (B) and (C) heated and melted is preferably advanced toward the die while being cooled to a temperature of 85 to 120°C, more preferably 100 to 120°C, in order to prevent foaming. Also, foaming can be prevented and moisture can be removed by exhausting from the barrel. The residence time in the extruder can be set according to the temperature profile and screw speed, and is preferably between 1 and 2.5 minutes.

[0057] In step (b) of extruding the molten mixture, the molten mixture advanced through the extruder is extruded from the die. The die temperature is preferably 85 to 120°C, more preferably 90 to 110°C. The water content in the mixture extruded in step (b) is preferably in the range of 10 to 50% by mass, more preferably 20 to 40% by mass, still more preferably 22 to 40% by mass, and most preferably 25 to 35% by mass. Then, the melt is extruded from a multi-hole strand nozzle.

[0058] In the next step (c) of cooling and drying the melt extruded from the nozzle, the strand extruded from the strand nozzle is cut with a rotary cutter to form pellets. At this time, in order to prevent sticking of the pellets, vibration is applied periodically or constantly, and it is preferable to remove the moisture in the pellets by hot air, dehumidified air, an infrared heater, or the like.

[0059] The pellets of the resin mixture composed of components (B) and (C) thus obtained are blended and melted with the pellets of component (A), pelletized, or directly used for molding the male molded surface fastener without being pelletized. At that time, moisture may be added and melted.

[0060] Next, a method for manufacturing the male molded surface fastener layer (I) constituting the present invention using such a resin or resin mixture will be described. Specifically, as a method, a melt of the resin or the resin mixture is flowed in a sheet form onto the surface of a metal roll having a large number of cavities in the shape of male engagement elements on the surface, and the melt of the resin or the resin mixture is press-fitted into the cavities. After solidification, it is peeled off from the metal roll surface and at the same time pulled out from the cavities to produce a sheet having a large number of male engagement elements on the surface.

[0061] More specifically described, when the male engagement element is corrugated, a ring-shaped mold with a thickness of 0.2 to 0.5 mm having the corrugated engagement element shape engraved on its outer circumference, a metal ring not engraved in such a shape, a ring-shaped mold with a thickness of 0.2 to 0.5 mm having the shape of the corrugated engagement element bent in the opposite direction to the above corrugated engagement element shape engraved on its outer circumference, and a metal ring not engraved in such a shape are sequentially stacked. By doing so, a mold roll having a large number of cavities in the shape of corrugated engagement elements and a row of cavities of the corrugated engagement element bent in the opposite direction on its outer peripheral surface is prepared.

[0062] Also, when the male engagement element is Y-shaped, a ring-shaped mold with a thickness of 0.2 to 0.5 mm having such a Y-shaped shape engraved on its outer circumference and a metal ring not engraved in such a shape are sequentially stacked. By doing so, a mold roll having a large number of rows of cavities of the Y-shaped engagement element on its outer peripheral surface is prepared.

[0063] In the above description, the case where the cavities in the shape of corrugated engagement elements facing the opposite direction to the ring-shaped mold having the cavities in the shape of corrugated engagement elements are stacked in units of one sheet has been described, but they may be stacked in units of two or more sheets.

[0064] Such a metal roll has, on its surface, a plurality of cavities bent in the circumferential direction of the roll arranged in a row in the circumferential direction, and further, such rows exist in a plurality of rows in the width direction of the metal roll. When the cavity is corrugated, the bending direction of the cavity is reversed in units of one row or in units of a plurality of rows.

[0065] At that time, the cavity becomes narrower from the metal roll surface towards the tip, and gradually bends in the circumferential direction of the metal roll halfway, and the tip is directed in a direction slightly approaching the metal roll surface (that is, a bifurcated shape). Alternatively, it has a bifurcated shape (that is, a Y-shaped) divided before and after in the column direction in the middle, and even if it is divided into a bifurcated shape, the total thickness after being divided into the bifurcated parts becomes narrower from the base to the tip, and it is preferable that the tip is directed in a direction slightly approaching the metal roll surface.

[0066] Since the cavity is bent in this way, when pulling out the male mold engaging element cooled from the cavity, the engaging element is likely to be cut. However, by using the resin mixture as described above, the occurrence of such cutting of the engaging element can be prevented.

[0067] As a specific method of casting the molten resin or resin mixture on the metal roll surface, the melt of the resin or resin mixture is extruded and pressed into the gap with another drum roll existing at a position opposite to this metal roll, and the cavity is filled with the same resin or resin mixture while forming a sheet having a uniform thickness on the roll surface. While the mold roll is rotating, the resin or resin mixture in the cavity is cooled and solidified by the refrigerant constantly circulating inside the roll, and at the same time, it is stretched by a nip roller with the gap adjusted so that the base of the obtained male mold forming surface fastener has a uniform thickness, and the cooled sheet is peeled off from the surface of the mold roll, and the male mold engaging element is forcibly pulled out from the cavity. Thereby, a male mold forming surface fastener layer (I) in which a large number of male mold engaging elements are arranged in a row on the surface is obtained.

[0068] The male mold forming surface fastener layer (I) obtained in this way satisfies either of the following (1) and (2). (1) A plurality of male engaging elements are arranged in a row. Each male engaging element rises from the substrate surface, bends in the row direction midway, and its tip portion faces in a direction approaching (slightly) the substrate surface. Further, the direction of bending is reversed in units of one row or multiple rows, and the height of the male engaging element is 1.2 mm or less. Or, (2) A plurality of male engaging elements are arranged in a row. Each male engaging element rises from the substrate surface and has a bifurcated shape that branches in the front and rear in the row direction midway. The tip portions of the bifurcated parts have a shape that faces in a direction approaching (slightly) the substrate surface. Further, the height of the male engaging element is 0.6 mm or less. Of course, the male engaging elements satisfying the above (1) and the male engaging elements satisfying the above (2) may coexist.

[0069] Regarding the specific degree to which the tip portions of the male engaging elements in the above (1) and (2) face in a direction approaching the substrate slightly, it is preferable that the lower end portion at the tip of the male engaging element is closer to the substrate by 2 to 15% of the height of the male engaging element than the lower end portion at the top of the male engaging element. These values are calculated from the average values of arbitrarily selected 10 male engaging elements.

[0070] In the present invention, as the height of the male engaging element, in the case of the shape of the above (1), it is 1.2 mm or less, preferably 0.6 to 0.95 mm, and in the case of the shape of the above (2), it is 0.6 mm or less, preferably 0.3 to 0.5 mm. This height is much lower than the height of the male engaging elements of ordinary molded surface fasteners or textile surface fasteners. This low height is extremely important for accelerating the biodegradation rate. However, if it is too low, the engaging force will decrease, so the above range is preferable.

[0071] Whether it is the shape of the above (1) or the shape of the above (2), it is preferable that the thickness of the male engaging element becomes thinner from the base to the tip. However, when using the above-described ring-shaped mold, inevitably, the width of the male engaging element (that is, the thickness of the ring-shaped mold) is substantially the same from the base to the tip of the male engaging element.

[0072] The substrate serving as the base on which such male engaging elements rise is preferably in the thickness range of 0.1 to 0.3 mm in terms of biodegradability, flexibility, and strength. And as the density of the male engaging elements present on such a substrate, it is 60 to 180 pieces / cm 2 , particularly preferably in the range of 90 to 150 pieces / cm 2 . And in the male forming surface fastener layer (I), such male engaging elements are arranged in a row in the same direction as the bending direction of the male engaging element (2) as shown in FIG. 1 (the direction of P or Q shown in FIG. 1), or in the middle of the male engaging element (2) as shown in FIG. 2, it is divided into two branches before and after in the Q direction shown in FIG. 2, and each of the divided ones has a shape extending in the separating direction (the direction of Q shown in FIG. 2), and they are arranged in a row in the same separating direction.

[0073] Furthermore, in the biodegradable front-back engaging type surface fastener of the present invention, it is preferable in terms of high engaging force and biodegradability that the male forming surface fastener layer (I) on the surface side has the rows of male engaging elements formed on the ridges (4) rising from the substrate as shown in FIGS. 1 and 2. In order to be formed on such ridges, a method of making the diameter of the ring-shaped mold for the engaging element slightly smaller than the diameter of the ring-shaped mold without the engaging element, a method of shifting the center of the ring-shaped mold, etc. are used. In this case, the height of the ridge-like raised portion is preferably 2 to 30% of the height of the male engaging element.

[0074] The fibers of the fiber layer (II) are directly joined to the substrate of the male forming surface fastener layer (I) constituting the present invention by fusion. Also, the surface on which the fiber loops of the fiber layer (II) exist and the surface on which the male engaging elements of the male forming surface fastener layer (I) protrude are in a front-back relationship, and preferably they are back-to-back. The fibers constituting this fiber layer (II) are made of polybutylene succinate substantially free of starch. The fiber loops can engage with the male engaging elements present on the surface of the male forming surface fastener, and a plurality of such fiber loops need to exist, and preferably a large number of them exist.

[0075] The fibers constituting this fiber layer (II) are made of polybutylene succinate substantially free of starch. If starch is contained, the strength of the resulting fibers decreases, and furthermore, a high engaging force with the male engaging element cannot be obtained. Regarding biodegradability, even if substantially no starch is contained, a satisfactory biodegradation rate can be obtained because the fibers are thin in shape. Here, "substantially free of starch" means that the starch content in the fiber layer (II) is 5% by mass or less, preferably 1% by mass or less, for example, 0% by mass. The content of polybutylene succinate in the fibers is preferably 80% by mass or more, more preferably 90% by mass or more, still more preferably 95% by mass or more, even more preferably 99% by mass, for example, 100% by mass.

[0076] As the fiber layer (II), a non-woven fabric layer or a tricot knitted fabric layer that easily forms a structure in which the surface fiber loops are substantially difficult to be pulled out from the surface of the fiber layer is a suitable layer. When the fiber layer (II) is a woven fabric layer like a normal hook-and-loop fastener, as a method for preventing the fiber loops existing on the surface from being pulled out from the woven fabric base fabric, a method of applying a commonly used backcoat resin can be considered. However, when the backcoat resin is applied to the back surface, as described above, the heat fusibility between the male molded hook-and-loop fastener layer (I) and the fiber layer (II) will be greatly impaired, and an adverse effect on biodegradability due to the backcoat resin layer will also occur. On the other hand, in the case of a non-woven fabric layer or a tricot knitted fabric layer, the pull-out resistance of the fiber loops can be sufficiently ensured by entanglement treatment or knitted fabric structure, and furthermore, since the pull-out resistance is enhanced by the heat fusion treatment with the male molded hook-and-loop fastener layer (I), there is an advantage that it is not necessary to apply a backcoat resin.

[0077] When the fiber layer (II) is a non-woven fabric layer, it is composed of a fine fiber layer (II-1) made of polybutylene succinate fibers with a fineness of 1.0 to 4.0 dtex and a thick fiber layer (II-2) made of polybutylene succinate fibers with a fineness of 6 to 20 dtex, and the total basis weight of (II-1) and (II-2) is 20 to 200 g / m 2

[0078] It is preferably joined to the back surface of the substrate so that (II-1) is on the (I) side. By having such a two-layer structure, a biodegradable front-back engaging type surface fastener is obtained that is excellent in engagement with the male engaging element on the front surface side, has excellent bonding strength with the back surface of the substrate, and has excellent shape retention of the fiber layer (II). When the fiber layer (II) is a non-woven fabric layer, the basis weight mass ratio of the fine fiber layer (II-1) and the thick fiber layer (II-2) constituting the non-woven fabric layer is preferably in the range of 80:20 to 20:80, more preferably in the range of 30:70 to 70:30.

[0079]

[0080] Also, when using a tricot knitted fabric layer as the fiber layer (II), it is preferable because a product with excellent holding property of the engagement force after repeating the engagement force and engagement peeling can be obtained. As a tricot knitted fabric, a product having a loop pile layer made of multifilament yarns formed on one side is preferably cited as a suitable example. Further, by raising the loop pile layer with a card cloth or the like, a tricot knitted fabric in which the multifilament yarns constituting the loop pile layer are dispersed to further increase the engagement force is also suitable.

[0080] And the yarns that make up such a tricot knitted fabric are multifilament yarns made of polybutylene succinate. As such multifilament yarns, multifilament yarns with a total fineness of 50 to 250 dtex, in which 8 to 20 filaments of 4 to 20 dtex are bundled, are preferable in terms of the holding property of the engagement force after repeating the engagement force and the engagement peeling. And as the areal density of the tricot knitted fabric, 50 to 500 g / m 2 is preferable. Further, in order to increase the engagement force more, a knitted fabric with a warp / weft ratio of tensile strength of 0.5 to 2.0 is preferable, and more preferably, a knitted fabric with a ratio of 1.1 to 1.6. Here, the warp and weft mentioned here mean that in the case of a tricot knitted fabric, the direction in which the loops are continuously knitted up is the warp direction.

[0081] However, polybutylene succinate has an extremely slow crystallization rate. Therefore, in ordinary melt spinning, sufficient crystal growth cannot be obtained, and only multifilament yarns with an extremely large elongation of 120 to 170% of the breaking elongation can be obtained. When such a multifilament yarn with a large breaking elongation is used in the knitting process, due to the large elongation of the multifilament yarn, troubles are likely to occur during the process. Furthermore, the obtained tricot knitted fabric also has a problem that it is difficult to obtain a stable engagement because the fiber loops are easily stretched by the engagement. Therefore, when producing a tricot knitted fabric using such a multifilament yarn made of polybutylene succinate with a large breaking elongation, it is difficult to produce the tricot knitted fabric itself, and furthermore, a tricot knitted fabric having sufficient engagement force and engagement force holding property cannot be obtained.

[0082] From the above, a polybutylene succinate multifilament yarn with a reduced breaking elongation is preferable. Specifically, it is preferable to use a polybutylene succinate multifilament yarn with a higher degree of crystallinity by reducing the spinning speed, increasing the draw ratio, performing sufficient heat treatment, or adding a crystallization accelerator to the resin, compared to ordinary polybutylene succinate multifilament yarns. And specifically, a polybutylene succinate multifilament yarn with a breaking elongation of 50 to 100%, particularly 55 to 85%, is preferable.

[0083] Such a fiber layer (II) is joined and integrated with the male mold forming surface fastener layer (I), preferably by thermocompression bonding to the back surface thereof. Specifically, it is preferable that the fiber layer (II) is partially melted and formed into a film by thermocompression bonding, and the fiber layer (II) is directly joined to the back surface of the substrate layer at the portion where it is melted and formed into a film. The partial thermocompression bonding of the fiber layer (II) to form a molten film means that 10 to 40% of the surface area of the fiber layer (II) is thermally fused, and the fibers in that portion are melted and formed into a film. Preferably, when a circle with a diameter of 20 mm is drawn on the surface of the fiber layer, both a fused portion and a non-fused portion are preferably mixed within any of the circles, and more preferably, both are present in any of the circles with a diameter of 15 mm. Also, as shown in FIG. 5, the end of the fiber layer (II) is overlapped with the end of the male mold forming surface fastener layer (I) such that the surface on which the male engaging element (2) is present is the front side and the surface on which the fiber loop (8) is present is the back side, and the overlapped portion (6) is thermocompression bonded so that the male engaging element (2) is on the front surface and the fiber loop (8) is present on the back surface at a location away from the location where the male engaging element is present (that is, the location where the male engaging element is present and the location where the fiber loop is present are not back to back, but extend in directions away from each other across the overlapped portion). The two may be joined.

[0084] As a specific method of joining and integrating, between a heating embossing roll heated to a temperature at which polybutylene adipate melts and a cooling roll whose surface is cooled and maintained at a temperature at which polybutylene adipate does not melt, an overlapping product of the male mold forming surface fastener layer (I) and the fiber layer (II) is inserted with the fiber layer (II) on the heating embossing roll side to join and integrate them. At that time, it is preferable to keep the temperature of the cooling roll sufficiently low so that the male engaging element present on the surface of the male mold forming surface fastener layer (I) is not crushed by heat. It is also preferable to cover the male engaging element with a heat-resistant elastomer resin such as silicone rubber and use a method of peeling the resin after integration.

[0085] FIG. 3 and FIG. 4 are diagrams schematically showing the heat-sealed state on the back side of an example of the biodegradable front-back engaging surface fastener of the present invention. However, as shown in FIG. 3, even if the heat-pressed portion (6) exists in a mesh-like manner on the surface of the fiber layer (II), or as shown in FIG. 4, the non-heat-pressed portion (7) remains circular and the heat-pressed portion (6) surrounds the periphery, or even in a shape where the heat-pressed portion exists on the surface of the fiber layer (II) in a discontinuous state.

[0086] That is, when the fiber layer (II) is a non-woven fabric, both ends and two locations in the middle of most of the fibers constituting the engaging element surface side (i.e., the non-bonding surface side) are fixed by heat pressing, and the unfixed portions form fiber loops. In particular, in terms of the engaging force, it is preferable that the non-heat-pressed portion bulges on the surface of (II). Of course, when the fiber layer (II) is a tricot knitted fabric, since the fiber loops are sufficiently fixed by the knitted fabric structure, there is little need to fix the fiber loops by heat pressing.

[0087] And in this heat-pressed and melt-filmed portion, the male mold forming surface fastener layer (I) and the fiber layer (II) are integrally heat-pressed. In the present invention, it is not necessary for the fiber layer (II) to be integrated over the entire back surface of the male mold forming surface fastener layer (I), and the fiber layer (II) may be integrated only at necessary locations such as the ends. And, as one form in which only the end portion of such a male molded surface fastener layer (I) is integrated with the fiber layer (II), as shown in FIG. 5, a tape-like material made of the male molded surface fastener layer (I) and a tape-like material made of the fiber layer (II) are overlapped so that only the joint portion (6) at each end overlaps, and the surface on which the male engaging element (2) of the male molded surface fastener layer (I) exists is the front side, and the surface on which the fiber loop (8) of the fiber layer (II) exists is the back side, and the male molded surface fastener layer (I) and the fiber layer (II) are overlapped so that the surface on which the male engaging element (2) exists and the surface on which the fiber loop (8) exists extend in directions away from the joint portion (6) respectively, and the overlapped portion (6) is thermocompression bonded to join the two, and an example is a structure in which the end of the male molded surface fastener layer (I) and the end of the fiber layer (II) are joined together. When joining the ends of such a male molded surface fastener layer (I) and the fiber layer (II) together, as shown in FIG. 5, at the joint portion (6), the end of the surface on which the male engaging element (2) of the male molded surface fastener layer (I) exists and the end of the surface on which the fiber loop (8) of the fiber layer (II) exists are overlapped, and the surfaces on which male engaging elements other than the overlapped portion (6) exist and the surfaces on which fiber loops exist extend in directions away from the overlapped portion (6) respectively, and in this state, the overlapped portion (6) is thermocompression bonded to join, and in the other case, the end of the opposite side surface (back surface) of the surface on which the male engaging element of the male molded surface fastener layer (I) exists and the end of the opposite side surface (back surface) of the surface on which the fiber loop of the fiber layer (II) exists are overlapped, and the surfaces on which male engaging elements other than the overlapped portion exist and the surfaces on which fiber loops exist extend in directions away from the overlapped portion respectively, and in this state, the overlapped portion is thermocompression bonded to join. There are two such cases, and in the present invention, either case may be used. From the viewpoint of productivity, in the former case described above, since the male engaging element (2) and the fiber loop (8) engage with each other at the overlapped portion (6) and the overlapped portion is fixed, and it can be joined in the fixed state, the joining state is stable and it can be joined surely, so it is preferable. FIG. 5 shows the state after joining in this former case. Furthermore, in the present invention, a substrate layer without male engaging elements extending from a portion where male engaging elements of the male molded surface fastener are present, or a substrate layer without fiber loops extending from a portion where fiber loops of the fiber layer (II) are present, may be used for joining such that the surface side is the side where the male engaging elements are present, the back side is the side where the fiber loops are present, and fiber loops may be present at a location away from the back side of the location where the male engaging elements are present. When joining using a substrate layer without engaging elements extending from the portion where the engaging elements are present as described above, it may be the case where only the male molded surface fastener layer (I) utilizes the substrate layer without male engaging elements, or only the fiber layer (II) utilizes the substrate layer without fiber loops, or even the case where both utilize the substrate layer without engaging elements. Tape-like objects obtained by joining the ends as described above or tape-like objects joined using a substrate layer without engaging elements extending from the portion where the engaging elements are present also have male engaging elements on the surface side and fiber loops on the back side. Therefore, for example, when bundling a rod-shaped object, an electric wire, etc., and winding the same tape-like object around it with the surface having the engaging elements facing outward, and then overlapping the back surface of the tape-like object after one round, the male engaging elements of the male molded surface fastener layer (I) present at one end and the fiber loops of the fiber layer (II) present at the other end will be engaged, and it can be used as a binding tape for maintaining the bundled state. When joining and using the ends of such a male molded surface fastener layer (I) and fiber layer (II), the fiber layer (II) needs to have strength against pulling, etc. alone. For this purpose, as the fiber layer (II), a woven or knitted fabric having fiber loops on the surface is preferable. Thus, in the present invention, the surface on which the male engagement element exists and the surface on which the fiber loop exists do not necessarily exist back-to-back with the substrate sandwiched therebetween as shown in FIGS. 1 and 2, and they may be offset as shown in FIG. 5. Preferably, since biodegradability is most likely to be effective, as shown in FIGS. 1 and 2, the surface on which the male engagement element exists and the surface on which the fiber loop exists are in a state of being back-to-back with the joined substrate sandwiched therebetween. The biodegradable front-back engagement type surface fastener according to one aspect of the present invention is, among the various biodegradable front-back engagement type surface fasteners described above, the surface (Is) on the opposite side of the surface of the substrate of the male molded surface fastener layer (I) where the male engagement element protrudes, and the surface (IIs) on the opposite side of the surface of the fiber layer (II) having the fiber loop are directly joined by fusion, and preferably 60% or more, more preferably 80% or more, still more preferably 90% or more, and even more preferably 100% of the area of the surface (Is) is directly covered by the surface (IIs). Also, preferably 60% or more, more preferably 80% or more, still more preferably 90% or more, and even more preferably 100% of the area of the surface (IIs) may be directly covered by the surface (Is).

[0088] The biodegradable front-back engagement type surface fastener of the present invention obtained in this way decomposes rapidly in the natural environment when discarded after use, and thus does not cause environmental destruction. Therefore, it is suitable as a tape for tying or bundling used in application fields such as agriculture, forestry, fishery, civil engineering, and construction, which are discarded in the natural environment after use.

[0089] Specifically, from the biodegradable front-back engaging type surface fastener of the present invention, a tape having a width of 5 mm to 50 mm, a length of 50 to 500 mm, and a length / width ratio of 8 to 100 is cut out such that the column direction of the male engaging elements becomes the length direction and both the male engaging elements and the fiber loops are present. This tape-like object is used as a tape for tying or bundling in the agricultural, forestry, and fisheries industries. For example, it can be used as a tying tape for tying the opening of a fruit bag, a bundling tape for harvested crops or bouquets, a tape for fixing seedlings, and a temporary fixing tape used in agriculture and forestry.

Example

[0090] Hereinafter, the present invention will be described in detail with reference to examples. In these examples and comparative examples, the engaging force was measured according to the method of JIS L3416. Two surface fasteners obtained were prepared, the front surface side of one surface fastener and the back surface side of the other surface fastener were overlapped, and both shear and peel were measured. Also, the biodegradability was measured by burying in soil at 40°C and measuring the period required for the biodegradable front-back engaging type surface fastener to decompose, the male engaging elements and the substrate sheet to lose strength, and easily fall apart and the form of the surface fastener to disappear. Note that the fiber layer (II) on the back surface side usually decomposes and falls apart more rapidly than the male molded surface fastener layer (I) on the front surface side. However, if the male molded surface fastener layer (I) decomposes more rapidly than the fiber layer (II), that fact was noted.

[0091] Example 1 [Preparation of molding resin] 50 parts by mass of Bio-PBS manufactured by Mitsubishi Chemical Corporation as polybutylene succinate, 43 parts by mass of hydroxypropyl ether-modified corn starch derived from corn with an amylose content of 80% by mass as starch, 1 part by mass of Elvano71-30 manufactured by DuPont Chemicals (fully saponified polyvinyl alcohol with a saponification degree of 99.3%) as polyvinyl alcohol, 0.95 part by mass (2.21% by mass based on starch) of natural montmorillonite modified with dimethyldi(hydrogenated tallow) quaternary ammonium chloride as clay, 0.09 part by mass (0.21% by mass based on starch) of stearic acid, and 4.96 parts by mass (11.5% by mass based on starch) of cellulose nanocrystal powder manufactured by Nippon Paper Industries Co., Ltd. were used, and these raw materials were mixed by the following method.

[0092] Specifically, among these raw materials, starch, polyvinyl alcohol, clay, stearic acid, and water were pelletized in advance only with these raw materials, and then this pellet and a polybutylene succinate pellet containing cellulose nanocrystal powder were blended and melted to form a male mold fastener. That is, the above-described steps (a), (b), and (c) were sequentially performed, and in this case, conditions within the range described above were used as suitable conditions. Further, at this time, clay and stearic acid were also mixed and pelletized, and a method was used in which this was blended with a pellet of polybutylene succinate during the molding of the male mold fastener. Further, water was added during the molding of the male mold fastener so that the water content in the obtained male mold fastener was 6 parts by mass (14.0% by mass based on starch).

[0093] [Preparation of Molding Die] As a mold, a ring-shaped mold with a thickness of 0.2 mm and a diameter of 211.9 mm, which has a corrugated engagement element shape engraved on its outer circumference, a metal ring with a flat outer peripheral surface without such an engraved shape, a thickness of 0.3 mm and a diameter of 212 mm, a ring-shaped mold with a thickness of 0.2 mm and a diameter of 211.9 mm, which has a corrugated engagement element shape engraved on its outer circumference and faces the opposite direction of the above-mentioned corrugated engagement element shape, and a metal ring with a flat outer peripheral surface without such an engraved shape, a thickness of 0.3 mm and a diameter of 212 mm are stacked in order. Thus, a mold roll with a width of 120 mm is prepared, which has a cavity with a corrugated engagement element shape and a cavity with a corrugated engagement element shape facing the opposite direction on its outer peripheral surface.

[0094] [Manufacture of male mold forming surface fastener] The raw material is blended and melted in the gap with another drum roll existing at a position opposite to the above-mentioned mold roll, and the melt (temperature: 105 °C) is extruded and compressed to fill the cavity with the melt and form a sheet with a uniform thickness on the roll surface. While the mold roll is rotating, the resin in the cavity is cooled by the water constantly circulating in the roll. After that, it is stretched by a nip roll with the gap 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 roll to manufacture a male mold forming surface fastener having a corrugated engagement element.

[0095] In this male mold forming surface fastener, polybutylene succinate is the continuous phase and starch is the dispersed phase. And in this male mold forming surface fastener, a plurality of male engagement elements are arranged in a row. Each male engagement element has a shape that rises from the surface of the substrate, bends in the row direction from the middle, and its tip is directed in a direction slightly approaching the surface of the substrate. The height is 0.8 mm and the engagement element density is 136 pieces / cm 2 And the row of male engagement elements was formed on a ridge with a height of 0.05 mm rising from the substrate.

[0096] And regarding the moldability when molding the obtained male - type molded - surface fastener (whether the male - type engaging elements can be pulled out of the cavity without breaking, or if they can be pulled out, whether there are no cracks in the middle, and whether there are no cracks in the base layer, etc.), there were no problems at all.

[0097] [Manufacture of non - woven fabric] A fiber web with a basis weight of 20 g / m² composed of machine - crimped fibers 51 mm in length and 2.0 dtex in thickness made of polybutylene succinate (tensile strength 3.2 g / dtex), and a fiber web with a basis weight of 100 g / m² composed of machine - crimped fibers 51 mm in length and 10 dtex in thickness made of polybutylene succinate (tensile strength 3.5 g / dtex) were overlapped, and both webs were made into a non - woven fabric by hydraulically entangling them. 2 were overlapped, and both webs were made into a non - woven fabric by hydraulically entangling them.

[0098] [Manufacture of biodegradable front - back engaging - type surface fastener] The non - woven fabric was overlapped on the back surface of the male - type molded - surface fastener such that the surface composed of 2.0 - dtex fibers was the surface in contact with the male - type molded - surface fastener. Then, the non - woven fabric was inserted between a heating roll (surface temperature: 100 °C) having lattice - shaped protrusions on its surface and a cooling roll (surface temperature: 20 °C) with the non - woven fabric on the heating - roll side, and thermocompression - bonded to directly join and integrate the non - woven fabric layer (II) to the back surface of the male - type molded - surface fastener layer (I). The size of the lattice of the back - surface non - woven fabric layer (II) is a square with a side length of 8 mm, 18% of the surface area of the non - woven fabric layer (II) is melted into a film by thermocompression bonding, and the non - woven fabric layer (II) is directly joined to the back surface of the base layer at the melted - film - formed locations. On the surface of the side of the non - woven fabric layer (II) opposite to the surface joined to the male - type molded - surface fastener layer (I), there are a large number of fiber loops that can engage with the male - type engaging elements, and that part is raised more than the thermocompression - bonded part.

[0099] Two biodegradable front - back engaging - type surface fasteners obtained in this way were prepared, and their front and back surfaces were engaged and the engaging force was measured. As a result, the shear force was 14.4 N / cm 2The peel strength is 1.43 N / cm, and it was found that all of them have excellent bonding strength as a hook-and-loop fastener. Further, in order to measure the biodegradability of the obtained biodegradable front-and-back engaging type hook-and-loop fastener, it was buried in soil with a depth of 2 cm in the factory, and the degree of biodegradation was observed at a rate of once every two weeks. It was found that both the male molded hook-and-loop fastener layer (I) and the non-woven fabric layer (II) were decomposed separately to such an extent that the hook-and-loop fastener shape could not be maintained after 22 weeks.

[0100] This biodegradable front-and-back engaging type hook-and-loop fastener was cut into a tape shape with a width of 6 mm and a length of 80 mm so that the rows of engaging elements were in the length direction parallel to the tape length direction. When this tape-like material was used as a tying tape for a bag covering a grape bunch, even when it was left in the field after use, almost no tape-like material was found the following year, and it was presumed that it had been biodegraded and returned to nature.

[0101] Example 2 In Example 1 above, as the raw material of the male molded hook-and-loop fastener, 70 parts by mass of polybutylene succinate, 25.8 parts by mass of modified starch, 0.6 parts by mass of polyvinyl alcohol, and 3.6 parts by mass of water (14.0% by mass based on starch) were changed, and the addition ratios of clay and stearic acid were 0.57 parts by mass and 0.052 parts by mass (2.2% by mass and 0.2% by mass based on starch), respectively. Otherwise, in the same manner as in Example 1, a male molded hook-and-loop fastener having corrugated engaging elements was manufactured. There was no problem with the moldability during molding as in Example 1. Then, a non-woven fabric manufactured in the same manner as in Example 1 above was overlaid on the back surface of this male molded hook-and-loop fastener and joined and integrated.

[0102] As a result of measuring the bonding strength by engaging the front and back surfaces of the biodegradable front-and-back engaging type hook-and-loop fastener thus obtained, the shear was 15.7 N / cm 2The peel was 1.65 N / cm, and like that of Example 1, it had excellent engaging force as a hook-and-loop fastener. Further, as a result of measuring the biodegradability of the obtained biodegradable front-and-back engaging type hook-and-loop fastener in the same manner as in Example 1, it was found that both the male molded hook-and-loop fastener layer (I) and the nonwoven fabric layer (II) were decomposed separately to such an extent that the hook-and-loop fastener shape could not be maintained at 24 weeks.

[0103] Then, when this biodegradable front-and-back engaging type hook-and-loop fastener was cut into a tape shape in the same manner as in Example 1 and used as a tying tape for grape bags, similar to the one in Example 1, the left-behind tape that was forgotten to be collected was hardly found the next year and was presumed to have been biodegraded and returned to nature.

[0104] Comparative Example 1 In the above Example 1, as the raw material of the male molded hook-and-loop fastener, 19 parts by mass of polybutylene succinate, 68 parts by mass of modified starch, 2.5 parts by mass of polyvinyl alcohol, and 8 parts by mass of water (11.8% by mass based on starch) were changed, and the addition ratios of clay and stearic acid were 1.84 parts by mass and 0.27 parts by mass (2.7% by mass and 0.4% by mass based on modified starch), respectively. Otherwise, a male molded hook-and-loop fastener having a corrugated engaging element was manufactured by the same method as in Example 1. In this male molded hook-and-loop fastener, polybutylene succinate was the dispersed phase and starch was the continuous phase. In the molded hook-and-loop fastener, many breaks of the hook-shaped engaging elements were observed, and further, it was difficult to peel the hook-and-loop fastener from the mold surface, and cracks occurred in the base sheet of the hook-and-loop fastener in some places.

[0105] Further, as a result of measuring the engaging force of the biodegradable front-and-back engaging type hook-and-loop fastener thus obtained, the shear was 3.4 N / cm 2The peel was 0.51 N / cm, far lower than that of Example 1, and it had problems in terms of the practicality as a hook-and-loop fastener. Further, as a result of measuring the biodegradability of the obtained biodegradable front-and-back engaging type hook-and-loop fastener in the same manner as in Example 1, it was found that the male molded hook-and-loop fastener layer (I) was disassembled into pieces to such an extent that it could not maintain the hook-and-loop fastener shape in 6 weeks, and the biodegradability rate was too fast. On the other hand, most of the nonwoven fabric layer (II) on the back side still maintained the nonwoven fabric shape at the 6-week time point.

[0106] Example 3 In Example 1 above, only polybutylene succinate was used as the raw material for the male molded hook-and-loop fastener, and without using modified starch, polyvinyl alcohol, moisture, clay, stearic acid, or cellulose nanofine powder, a male molded hook-and-loop fastener was manufactured in the same shape as in Example 1, and a nonwoven fabric was joined and integrated on its back surface in the same manner as in Example 1.

[0107] Regarding the moldability of the male molded hook-and-loop fastener, breaks in the hook-shaped engaging elements were observed here and there. Further, as a result of measuring the engaging force of the obtained hook-and-loop fastener, the shear was 17.1 N / cm 2 and the peel was 1.71 N / cm, and there were no problems regarding the engaging force. However, as a result of measuring the biodegradability of the obtained biodegradable front-and-back engaging type hook-and-loop fastener in the same manner as in Example 1, it was found that it took 34 weeks for the male molded hook-and-loop fastener layer (I) on the front surface side to be disassembled into pieces to such an extent that it could not maintain the hook-and-loop fastener shape. Although it was inferior to that of Example 1 in terms of biodegradability, it was completely decomposed within one year and did not pose a fatal problem in terms of using it as a tying material for the agriculture, forestry, and fisheries industries.

[0108] Example 4 In Example 1 above, the raw materials were the same as in Example 1, the shape of the cavity was changed, and each male engaging element rose from the surface of the base body, had a bifurcated Y-shaped configuration that branched front and back in the column direction in the middle, and its tip had a shape approaching the surface of the base body, with a height of 0.45 mm and a density of 147 elements / cm of the male engaging elements 2A male - type molded surface fastener was manufactured. Then, a non - woven fabric manufactured by the same method as in Example 1 was overlaid on the back surface of this male - type molded surface fastener and joined and integrated.

[0109] As a result of measuring the engaging force of the biodegradable front - back engaging type surface fastener thus obtained, the shear was 16.6 N / cm 2 , and the peel was 2.70 N / cm. Similar to the one in Example 1, it had an excellent engaging force as a surface fastener. Furthermore, as a result of measuring the biodegradability of the obtained biodegradable front - back engaging type surface fastener in the same manner as in Example 1, it was found that at 22 weeks, both the male - type molded surface fastener layer (I) on the front surface and the non - woven fabric layer (II) on the back surface side were decomposed into pieces to such an extent that they could no longer maintain the surface fastener shape.

[0110] Then, when this biodegradable front - back engaging type surface fastener was cut into a tape shape in the same manner as in Example 1 and used as a tying tape for grape bags, similar to the one in Example 1, the tape left forgotten was hardly found the next year and was presumed to have been biodegraded and returned to nature.

[0111] Comparative Example 2 In Example 1 above, except that the mold was changed to a ring - shaped mold having a cavity such that the height of the male engaging element was 2.0 mm and the width was 0.3 mm, a male - type molded surface fastener having a corrugated engaging element with a height of 1.8 mm and an engaging element density of 70 pieces / cm 2 was manufactured. Then, a non - woven fabric manufactured by the same method as in Example 1 was overlaid on the back surface of this male - type molded surface fastener and joined and integrated.

[0112] As a result of measuring the engaging force of the biodegradable front - back engaging type surface fastener thus obtained, the shear was 17.8 N / cm 2, the peel was 1.81 N / cm. Similar to that of Example 1, it had excellent engaging force as a hook-and-loop fastener. However, as a result of measuring the biodegradability of the obtained biodegradable front-and-back engaging type hook-and-loop fastener in the same manner as in Example 1, it was found that it took 50 weeks for the male mold forming surface fastener layer (I) on the surface to be biodegraded. The product of this comparative example could not be said to be rapidly biodegradable. This was due to the high and thick male engaging elements being densely packed.

[0113] Comparative Example 3 In the above Example 3, except for changing to a ring-shaped mold having a Y-shaped cavity such that the height of the male engaging element was 1.0 mm and the width was 0.3 mm, in the same manner as in Example 3, a corrugated engaging element with a height of 1.0 mm was used at an engaging element density of 150 pieces / cm 2 to manufacture a male mold forming surface fastener. Then, a non-woven fabric manufactured in the same manner as in Example 1 above was overlaid on the back surface of this male mold forming surface fastener and joined and integrated.

[0114] As a result of measuring the engaging force of the biodegradable front-and-back engaging type hook-and-loop fastener thus obtained, the shear was 18.2 N / cm 2 , the peel was 3.05 N / cm. Similar to that of Example 1, it had excellent engaging force as a hook-and-loop fastener. However, the biodegradability of the obtained biodegradable front-and-back engaging type hook-and-loop fastener was such that it took 48 weeks for the male mold forming surface fastener layer (I) on the surface to be biodegraded, and it was found that it had slow biodegradability. This was due to the male engaging elements being high, thick, and densely packed, and moreover spreading in a Y shape so as to cover the surface of the male mold forming surface fastener.

[0115] Example 5 In the above Example 1, except for changing to a ring-shaped mold having a cavity such that the height of the male engaging element was 1.09 mm and the width was 0.25 mm, in the same manner as in Example 1, a corrugated engaging element with a height of 1.06 mm was used at an engaging element density of 110 pieces / cm 2A male - type molded - surface fastener was manufactured. Then, a non - woven fabric manufactured by the same method as in Example 1 was overlaid on the back surface of this male - type molded - surface fastener and joined and integrated.

[0116] As a result of measuring the engaging force of the biodegradable front - back engaging - type surface fastener thus obtained, the shear was 20.3 N / cm 2 , and the peel was 2.11 N / cm. Similar to the one in Example 1, it had excellent engaging force as a surface fastener. And the biodegradability of the obtained biodegradable front - back engaging - type surface fastener was such that the male - type molded - surface fastener layer (I) on the surface was decomposed at 26 weeks and fell apart, and the non - woven fabric layer (II) on the back surface had been completely decomposed and had no non - woven fabric shape by then. From this, although the one in this example was slightly inferior to the one in Example 1, it was rapidly biodegradable.

[0117] Example 6 In Example 3 above, except that it was changed to a ring - shaped mold having a Y - shaped cavity such that the height of the male engaging element was 0.42 mm and the width was 0.15 mm, in the same manner as in Example 3, a corrugated engaging element with a height of 0.45 mm was used at an engaging element density of 147 pieces / cm 2 to manufacture a male - type molded - surface fastener. Then, a non - woven fabric manufactured by the same method as in Example 1 was overlaid on the back surface of this male - type molded - surface fastener and joined and integrated.

[0118] As a result of measuring the engaging force of the biodegradable front - back engaging - type surface fastener thus obtained, the shear was 17.7 N / cm 2 , and the peel was 2.77 N / cm. Similar to the one in Example 1, it had excellent engaging force as a surface fastener. And it was found that the biodegradability of the obtained biodegradable front - back engaging - type surface fastener was such that both the male - type molded - surface fastener layer (I) on the surface and the non - woven fabric layer (II) on the back surface were decomposed and fell apart at 26 weeks. From this, it was found that the one in this example had appropriate biodegradability.

[0119] Example 7 In Example 1 above, as the fiber layer joined to the back side of the male mold forming surface fastener, a surface of a tricot knitted fabric made of a multifilament yarn (manufactured by Kuraray Nishiwajo) with a breaking elongation of 75% in which 12 filaments of 8.8 dtex made of polybutylene succinate are bundled was raised to form fiber loops on the surface, and one side was covered with fiber loops and had a basis weight of 150 g / m 2 A biodegradable front-back engaging type surface fastener was manufactured in the same manner as in Example 1, except that the tricot knitted fabric was used.

[0120] As a result of measuring the engaging force by engaging the front and back surfaces of the obtained biodegradable front-back engaging type surface fastener, the shear was 16.7 N / cm 2 and the peel was 1.68 N / cm, indicating that it has excellent engaging force as a surface fastener. Also, when the engaging and peeling were repeated 30 times, the shear was 16.1 N / cm 2 and the peel was 1.49 N / cm, and it was found that it also has better engaging force retention than that of Example 1 in this regard. And when the engaging and peeling were repeated 50 times, there were not so many fiber loops pulled out from the tricot knitted fabric, and there were no problems in appearance such that the surface of the tricot knitted fabric swelled randomly due to that.

[0121] Furthermore, as a result of measuring the biodegradability of the obtained biodegradable front-back engaging type surface fastener in the same manner as in Example 1, it was found that both the male mold forming surface fastener layer (I) and the tricot knitted fabric layer (II) were decomposed separately to the extent that the surface fastener shape could not be maintained in 25 weeks.

[0122] And when this biodegradable front-back engaging type surface fastener was cut into a tape shape in the same manner as in Example 1 and used as a tying tape for grape bags, similar to the one in Example 1, the tape left forgotten on the ground was hardly found the next year and was presumed to have been biodegraded and returned to nature.

[0123] Example 8 In Example 3 above, a biodegradable front-and-back engaging type surface fastener was produced in the same manner as in Example 3, except that a tricot fabric similar to that in Example 7 was used as the fiber layer in contact with the back side of the male mold forming surface fastener.

[0124] As a result of measuring the engaging force by engaging the front and back surfaces of the obtained biodegradable front-and-back engaging type surface fastener, the shear was 19.8 N / cm. 2 The peel was 2.00 N / cm, and it was found that it had excellent engaging force as a surface fastener. Also, when the engaging and peeling were repeated 30 times, the shear was 19.1 N / cm. 2 The peel was 1.79 N / cm, and it was also found that in this regard, it had better engaging force retention than that of Example 3. And when the engaging and peeling were repeated 50 times, there were not so many fiber loops pulled out from the tricot fabric, and there were no aesthetic problems such that the surface of the tricot fabric was randomly raised thereby.

[0125] Furthermore, as a result of measuring the biodegradability of the obtained biodegradable front-and-back engaging type surface fastener in the same manner as in Example 3, it was found that both the male mold forming surface fastener layer (I) and the tricot fabric layer (II) were decomposed separately to such an extent that the surface fastener shape could not be maintained in 34 weeks.

[0126] Then, when this biodegradable front-and-back engaging type surface fastener was cut into a tape shape in the same manner as in Example 3 and used as a tying tape for grape bags, similar to the one in Example 3, the tape left forgotten on the ground was hardly found the next year and was presumed to have been biodegraded and returned to nature.

Explanation of Signs

[0127] 1: Substrate 2: Wavy male engaging element 3: Y-shaped male engaging element 4: Ridge-like swelling 5: Fiber layer 6: Location where the fiber layer is melted into a film (joint) 7: Location where the fiber layer is not melted into a film 8: Fiber loop

Claims

Claim 1 A male - type forming - surface fastener layer (I) having a substrate and a plurality of male - type engaging elements protruding from the surface of the substrate, wherein both the substrate and the male - type engaging elements contain polybutylene succinate (A) and satisfy the following condition (1), and a fiber layer (II) formed from fibers made of polybutylene succinate (A), having a plurality of fiber loops on one side thereof that can engage with the male - type engaging elements, and further satisfying the following condition (2). A biodegradable front - and - back engaging - type surface fastener in which the fibers of the fiber layer (II) are directly joined to the substrate of the male - type forming - surface fastener layer (I) by fusion. (1) The plurality of male - type engaging elements are arranged in a row. Each male - type engaging element has a shape that rises from the substrate surface, bends in the row direction from the middle thereof, and the tip thereof faces a direction approaching the substrate surface, and the height is 1.2 mm or less, or each male - type engaging element has a bifurcated shape that rises from the substrate surface and is divided before and after in the row direction in the middle thereof, and the height is 0.6 mm or less. (2) The surface on which the fiber loops of the fiber layer (II) exist and the surface on which the male - type engaging elements of the male - type forming - surface fastener layer (I) protrude are in a front - and - back relationship. The fiber layer (II) is partially melt - formed into a film by thermocompression bonding, and the fiber layer (II) is directly joined to the back surface of the substrate at the melt - formed portion. Claim 2 The fiber layer (II) is a non - woven fabric layer, and this non - woven fabric layer is composed of a fine - fiber layer (II - 1) made of fibers with a fineness of 1.0 to 4.0 dtex and a thick - fiber layer (II - 2) made of fibers with a fineness of 6 to 20 dtex. The total basis weight of the fine - fiber layer (II - 1) and the thick - fiber layer (II - 2) is 20 to 200 g / m2, and further, the fine - fiber layer (II - 1) is joined to the back surface of the substrate so as to be on the side of the male - type forming - surface fastener layer (I). The biodegradable front - and - back engaging - type surface fastener according to Claim 1. Claim 3 The fibers constituting the thick - fiber layer (II - 2) have crimps, and the thick - fiber layer (II - 2) and the fine - fiber layer (II - 1) are integrated as a non - woven fabric layer by entanglement. The biodegradable front - and - back engaging - type surface fastener according to Claim 2. Claim 4 The fiber layer (II) is a tricot knitted fabric formed from multifilament yarns in which filaments made of polybutylene succinate are gathered. The biodegradable front - and - back engaging - type surface fastener according to any one of Claims 1 to 3. Claim 5 The biodegradable front and back engagement type surface fastener according to claim 4, wherein the multifilament yarn in which filaments made of polybutylene succinate are converged has an elongation at break of 50 to 100%.

6. The biodegradable front and back engagement type surface fastener according to any one of claims 1 to 5, wherein the rows of male engagement elements are formed on ridges rising from the substrate.

7. Starch (B) is added to the polybutylene succinate (A) forming the male molded surface fastener layer (I), and the polybutylene succinate (A) is the continuous phase and the starch (B) is the dispersed phase. The biodegradable front and back engagement type surface fastener according to any one of claims 1 to 6.

8. The biodegradable front and back engagement type surface fastener according to claim 7, wherein the starch (B) contains a modified starch, and 45% by mass or more of the starch (B) is amylose-based starch.

9. The biodegradable front and back engagement type surface fastener according to claim 7 or 8, wherein polyvinyl alcohol (C) is mixed in the dispersed phase.

10. The biodegradable front and back engagement type surface fastener according to claim 9, wherein the mass ratio of the polybutylene succinate (A) to the total mass of the polybutylene succinate (A), starch (B), and polyvinyl alcohol (C) constituting the male molded surface fastener layer (I) is 45 to 90%.

11. The biodegradable front and back engagement type surface fastener according to claim 8, wherein the modified starch is an etherified starch containing a hydroxyalkyl group.

12. The biodegradable front and back engagement type surface fastener according to any one of claims 7 to 11, wherein clay is mixed in the dispersed phase.

13. The biodegradable front and back engagement type surface fastener according to any one of claims 7 to 12, wherein the dispersed phase contains 3 to 30% water based on the mass of the starch (B).

14. The biodegradable front and back engagement type surface fastener according to any one of claims 7 to 13, wherein a saturated fatty acid or its metal salt is added to the dispersed phase.

15. The biodegradable front and back engagement type surface fastener according to any one of claims 7 to 14, wherein fine powder of cellulose is added to the continuous phase.

16. A tape made of the biodegradable front and back engagement type surface fastener according to any one of claims 1 to 15, wherein rows of engagement elements are present parallel to the tape length direction, and the tape is for tying or bundling in the agricultural, forestry, and fisheries industries.

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