Surface fastener made of fiber and method for manufacturing the same

The present invention provides a surface fastener made of a woven/knitted fabric which is extremely thin and flexible. Designs and the like on a rear face side of the fastener can be clearly seen through engaging elements and a substrate. Also, the fastener has a high productivity, thereby allowing a rational price setting. In a surface fastener made of a fiber woven/knitted fabric including a large number of female and/or male engaging elements which are woven simultaneously with weaving of a ground woven/knitted fabric formed of a ground structure and which project from a surface of the woven/knitted fabric, all of warp and weft constituting the ground structure and a yarn constituting the engaging elements are made of monofilament, synthetic resin applied to a rear face of the ground woven/knitted fabric adheres intensively to crossing portions of the monofilaments constituting the warp, the weft, and the engaging elements, and gaps are formed between weaving/knitting structure of the monofilaments constituting the warp, the weft, and the engaging elements.

BACKGROUND OF THE INVENTION
 1. Field of the Invention
 The present invention relates to a surface fastener made of fiber
 comprising at least a large number of engaging elements woven/knitted into
 a surface of a woven/knitted fabric obtained by weaving/knitting, the
 engaging elements being woven/knitted simultaneously with weaving/knitting
 of the woven/knitted fabric, and to a method for manufacturing the
 fastener.
 2. Description of the Related Art
 The surface fastener of this type generally comprises a male engaging
 member having a large number of hook-shaped or mushroom-shaped male
 engaging elements formed to stand on a surface of a flat substrate and a
 female engaging member having a large number of loop-shaped female
 engaging elements rising in close contact with each other on a flat
 substrate. By setting the female and male engaging members with their
 faces on which the engaging elements are formed facing each other and by
 pushing the male and female members against each other, the male and
 female engaging elements are engaged with each other to join the male and
 female engaging members to each other. By peeling the male and female
 engaging members from each other, the engaged male and female engaging
 elements are detached from each other.
 The surface fastener having the above structure is applied to extremely
 many fields from daily necessities to industrial material. In recent
 years, a molded surface fastener made of synthetic resin and obtained by
 integrally and simultaneously molding fine male engaging elements and a
 flat substrate has taken the place of a woven or knitted surface fastener
 and has been put to actual use. The molded surface fastener has been used
 as fasteners of various diapers and sanitary napkins which are liable to
 be in direct contact with user's skin.
 The most general structure of the female engaging member to be engaged with
 and detached from the male engaging member is a so-called pile
 woven/knitted fabric having a large number of loops formed to stand on a
 ground structure of the woven/knitted fabric made of fiber. The piles
 (loops) are usually obtained by weaving or knitting multifilament into the
 ground structure of the pile woven/knitted fabric. As another type of
 female engaging member, a general nonwoven cloth having a surface dense
 with fine piles has come to be used, as the above fine engaging elements
 of the integrally molded surface fastener has been put to actual use.
 As warp and weft constituting yarns of a substrate woven/knitted fabric for
 weaving, fixing, and supporting the male or female engaging elements, a
 twine made of multifilament or a normal spun yarn is used. A purpose for
 this is to further firmly hold monofilament or multifilament forming the
 male or female engaging elements by a weaving/knitting structure formed of
 warp and weft and to prevent the engaging elements from falling out of the
 substrate, by utilizing a friction force of a rough surface of the twine
 and flexibility of the twine in a shearing direction. Therefore, a density
 of weaving of the substrate is naturally set at a large value.
 Japanese Patent Publication No. 55-38121 discloses an example wherein the
 loops as the female engaging elements are formed of a single yarn of 90 d
 made of the twine of multifiber. In a surface fastener disclosed in this
 Japanese Patent Publication, warp and weft constituting yarns of the
 ground structure of the woven fabric are formed of twines made of
 multifiber. A single rubber yarn is used as a part of the warp, and the
 ground structure is woven while stretching the rubber yarn. The loops as
 the female engaging elements and the loops to be used for the hooks as the
 male engaging elements are firmly tied and fixed to the ground structure
 by contraction of the woven rubber yarn when weaving is finished.
 On the other hand, the variety of use of the surface fastener of this type
 is further increased. In the same industrial field, there is a strong need
 for a surface fastener which fits for material, a structure, or a color of
 clothes in a field of clothes, for example, wherein a fashion sense is
 required. Particularly, the surface fastener has recently come to be used
 frequently not only for underwear but also for outerwear. In thin clothes
 made of a lace fabric, for example, the surface fastener itself is
 required to be thin and to have transparency and flexibility throughout
 the fastener so as to be adapted to the material or structure of the
 clothes. Further, in addition to the above needs, there is a need for a
 surface fastener which is thin and has a strong engaging force in a large
 field of engaging and detaching devices for various outerwear and bags,
 for example. Also, in a fastener portion of various sportswear and bags,
 for example, it is required to see and recognize various designs and
 colors of a logotype and the like on the clothes or bags through the
 surface fastener, even if the fastener is thick.
 In the surface fastener disclosed in the above Japanese Patent Publication,
 however, the density of weaving of the substrate is increased by using the
 rubber yarn, and the majority of the used yarns is twine. Therefore, it is
 impossible to obtain a thin and flexible surface fastener. In addition, as
 is apparent from another example disclosed in the above Japanese Patent
 Publication, a large number of piles are densely formed to stand on the
 surface of the flat substrate made of fiber particularly in the female
 engaging member of the conventional surface fastener, as described above.
 As a result, a rear side of the surface fastener can not be seen through
 due to the piles densely formed on a front face of the fastener, and this
 defect can not be overcome even if any thought is put into designing the
 flat substrate.
 Therefore, conventionally, desired designs, letters, or marks are applied
 to a surface of a product including a surface of a surface fastener after
 the fastener is mounted to the product, or necessary designs are applied
 to the surface of the surface fastener in advance. In the former case,
 various problems based on a difference in dyeing properties of the surface
 fastener and a member of clothes and the like to be mounted with the
 fastener are liable to be generated, and in addition, two steps of
 operation are required to apply designs and the like. In the latter case,
 a number of steps is increased, and in addition, positioning of the
 designs on the surface fastener to the designs on the product in mounting
 of the fastener is complicated, thereby significantly decreasing a
 producing efficiency. Furthermore, shapes of the designs on the pile face
 are easily deformed, the designs on the pile face may be displaced from
 the designs on the clothes body over time, and a difference in clearness
 of colors of designs on the clothes body and the fastener is liable to be
 generated.
 SUMMARY OF THE INVENTION
 The present invention has been accomplished to solve the above problems,
 and it is a first object of the invention to provide an extremely thin and
 flexible surface fastener made of fiber. It is a second object of the
 invention to provide a surface fastener wherein a design and the like on a
 rear face side can be clearly seen through engaging elements and a
 substrate. It is a third object of the invention to provide a surface
 fastener wherein a manufacturing efficiency of the surface fastener is
 improved so as to increase productivity, thereby allowing a rational price
 setting.
 The above objects can be achieved by the inventions described below.
 The present inventors have found that a constituting member which has
 conventionally been left out of consideration in a surface fastener made
 of fiber is the most suitable for solving the above problems as a result
 of a hard study. In other words, in the conventional surface fastener made
 of fiber, it has been considered that an engaging rate of the female
 engaging elements with the hooks as opposed male engaging elements is
 increased and a peeling strength is increased by densely forming as large
 number of piles as possible.
 On the other hand, it has been considered to be desirable to increase a
 density of weaving of the substrate and to firmly bind base ends of the
 engaging elements by warp and weft in order to fix the male or female
 engaging elements to the substrate. However, it has become clear that
 fixing of the base ends of the engaging elements to the substrate depends
 on back coating rather than the density of weaving of the substrate.
 Therefore, it is unnecessary to use twine as warp and weft which are
 constituting material of the substrate.
 As a result of further study, it has been found that a sufficient engaging
 force and peeling strength with the opposed male engaging elements can be
 ensured even if the loops (piles) formed to stand on the surface of the
 flat substrate are formed of monofilament as far as a shape of the pile is
 maintained as described above.
 Thus, in order to stably maintain the loops on the surface of the substrate
 keeping the shape of the piles, synthetic resin is coated on the rear face
 of the flat substrate to fix the base ends of the loops to the substrate
 in general as disclosed in the above Japanese Patent Publication. However,
 the surface fastener of this type is engaged and peeled frequently and
 repeatedly in most cases, and a securing function may be lost in a short
 term if the securing by the synthetic resin is weak. In order to prevent
 this, it is necessary to increase an amount of the synthetic resin to be
 coated on the rear face of the substrate. Increase of the amount of the
 synthetic resin decreases flexibility of the flat substrate, and in
 addition, decreases transparency of the flat substrate even in a case the
 substrate is formed to be thin. This means that the fastener can not keep
 up with the above increase in variety of the surface fastener, and its
 application is limited.
 Therefore, the present inventors have studied further and found that loops
 wherein a shape of piles can be kept with sufficient durability can be
 formed by appropriately selecting quality of material of synthetic resin
 to be coated and of respective yarns constituting the surface fastener and
 by appropriately coating synthetic resin on the rear face of the
 substrate, even if the amount of the synthetic resin to be coated on the
 rear face of the substrate is decreased.
 According to a first aspect of the invention, there is provided a surface
 fastener made of fiber including a large number of engaging elements which
 are woven/knitted simultaneously with weaving/knitting of a ground
 woven/knitted fabric formed of a ground structure and which project from a
 surface of the woven/knitted fabric, wherein all of yarns constituting the
 ground structure and a yarn constituting the engaging elements are made of
 monofilament.
 The surface fastener made of fiber of the invention includes a surface
 fastener wherein a large number of male or female engaging elements are
 solely formed to stand on a surface of the woven/knitted fabric and a
 so-called self engaging type of surface fastener which itself can be
 engaged and detached wherein male and female engaging elements exist in a
 mixed state.
 The most remarkable feature of the invention is that all of the warp and
 the weft constituting the ground structure and the yarn constituting the
 engaging elements are made of the monofilament. By using the monofilament
 for all the constituting yarns of the surface fastener, a preparing step
 of weaving/knitting is made simple, thereby increasing a productivity.
 Simultaneously, by selecting a fineness (thickness) of each the
 constituting yarn streak, a Hook-and-Loop fastener with any thickness such
 as a thick fastener or an extremely thin fastener can be arbitrarily
 manufactured. Furthermore, by setting a weaving density at a low value,
 gaps can be formed in the weaving/knitting structure formed of the
 monofilaments for the warp, the weft, and the engaging elements. Also, in
 the female surface fastener, because the engaging elements are formed of
 the monofilament, transparency can be ensured.
 Preferably, in order to firmly secure the male and/or female engaging
 elements made of monofilaments to the ground woven/knitted fabric and to
 ensure transparency, synthetic resin applied to a rear face of the ground
 woven/knitted fabric adheres intensively to crossing portions of the
 monofilaments constituting the warp, the weft, and the engaging elements,
 and gaps are formed in weaving/knitting structure of the monofilaments
 constituting the warps, the wefts, and the engaging elements.
 Preferably, the engaging elements include a large number of female engaging
 elements, the monofilament constituting the female engaging elements has a
 self torsion property, and torsion is generated in base end portions of
 the female engaging elements projecting from the woven/knitted fabric.
 In the present invention, the female engaging elements are made of
 monofilament, torsion is generated in the projecting base end portions of
 loops formed by weaving or knitting the monofilament into the ground
 structure due to the self torsion property, and the loop itself holds the
 warp or the weft under which the monofilament of the loop passes.
 Therefore, the female engaging element itself has a property for
 maintaining the shape. Thus, when synthetic resin is coated on the rear
 face of the substrate, for example, an amount of the resin to be coated
 can be extremely small as compared with that in conventional art.
 Further preferably, the monofilament for the female engaging elements has a
 sectional shape of a polygon with three or more angles. If the
 monofilament has a triangular shape in section, edge portions (edge lines)
 of the monofilament are rubbed by other members in weaving or knitting,
 and torsion is automatically generated in the projecting base end portions
 of the loops formed of the monofilament after weaving or knitting.
 Therefore, the invention does not require a special treatment for causing
 the loops to exhibit their self torsion property.
 Still preferably, the monofilament for the female engaging elements is
 crimped when heated. A heating treatment as a heating treatment for
 setting or a finishing processing is necessarily applied to the surface
 fastener made of fiber of this type after weaving or knitting. In the
 present invention, when the heating treatment is applied to the fastener,
 self torsion is generated in the base end portion of the loop formed of
 the monofilament projecting from the substrate due to crimp. The
 monofilament having such a crimping property can be manufactured by
 combining and spinning fiber material with high shrinking property and
 fiber material with low shrinking property arranged side by side. The
 quality of material is obtained by combining various kinds of
 thermoplastic synthetic resin, but it is desirable that combined kinds of
 material have affinity with each other. Such quality of material is
 obtained by combining and spinning normal polyester and metamorphic
 polyester, for example.
 Preferably, the engaging elements are a large number of male engaging
 elements so that the obtained surface fastener is a male surface fastener.
 A shape of the male engaging element may be a hook shape, or a mushroom
 shape.
 The surface fastener may be a so-called self engaging type of surface
 fastener made of fiber, wherein the large number of engaging elements
 comprise loop-shaped female engaging elements and hook-shaped or
 mushroom-shaped male engaging elements, and the female and male engaging
 elements exist in a mixed state.
 A preferred range of fineness (thickness) of each monofilament as
 constituting material of the surface fastener are defined as follows.
 Finenesses of the yarns constituting the ground structure are in a range
 of 2 d to 100 d. A fineness of the monofilament constituting the female
 engaging elements is in a range of 2 d to 70 d. In a normal surface
 fastener made of fabric as disclosed in the above Japanese Patent
 Publication, a warp constituting the ground structure is a twine of 140 d
 made of multifiber, a weft is a twine of 200 d made of multifiber, and a
 loop yarn constituting the female engaging elements is a twine of 90 d.
 Thus, as compared with this normal fastener, it would be understood that a
 fineness of any yarn used in the invention which is a combination of the
 above mentioned features is remarkably small. Such monofilaments with
 small finenesses can be used mainly because of the above property of the
 female engaging element for maintaining its shape.
 A fineness of the monofilament constituting the male engaging elements is
 preferably in a range of 70 d to 300 d. Alternatively, the fineness of the
 monofilament constituting the male engaging elements may be in a range of
 100 d to 150 d.
 A preferred fineness (thickness) of each constituting yarn of the self
 engaging type of surface fastener is defined as follows. Finenesses of the
 yarns constituting the ground structure are in a range of 2 d to 100 d, a
 fineness of the monofilament constituting the female engaging elements is
 in a range of 2 d to 70 d, and a fineness of the monofilament constituting
 the male engaging elements is in a range of 70 d to 300 d.
 The fineness of the monofilament as the constituting yarn for the male
 engaging elements is in a range of 70 d to 300 d so as to ensure a
 necessary engaging force of the male engaging elements with the female
 engaging elements, and the fineness of the monofilament for the male
 engaging elements is properly determined according to usage of the surface
 fastener and the fineness of the female engaging elements.
 By combining the finenesses in the above ranges, an engaging strength and a
 peeling strength which are necessary to the surface fastener can be
 obtained, and a surface fastener which is thin and flexible and wherein a
 rear face can be seen through from a front face of the fastener can be
 obtained.
 In a case the surface fastener is especially formed of a woven fabric, the
 ground structure is formed of a weaving structure comprising warp and
 weft, a fineness of the warp is in a range of 2 d to 100 d, and a fineness
 of the weft is in a range of 30 d to 100 d. The fineness of the warp which
 is further desirable to obtain a thinner surface fastener is in a range of
 15 d to 70 d.
 And preferably, all of the monofilaments are made of transparent or
 semitransparent material so as to ensure further transparency such that
 the rear face of the surface fastener can be reliably seen through.
 According to a second aspect of the invention, there is provided a method
 for manufacturing a surface fastener made of fiber according to the first
 aspect comprising only the male or female engaging elements or the mixed
 male and female engaging elements. The method comprises the steps of
 weaving or knitting the monofilament which is constituting material of
 female and/or male engaging elements while forming loops on a surface of
 the ground woven/knitted fabric simultaneously with weaving/knitting of
 the ground woven/knitted fabric by using the yarns made of monofilament,
 thermally setting the completed woven/knitted fabric to fix a
 weaving/knitting shape, coating synthetic resin material on a rear face of
 the set woven/knitted fabric to form a thin film, spraying air on the film
 in a direction from the rear face side to a front face side of the
 woven/knitted fabric to concentrate the film on crossings of respective
 constituting yarns of the woven/knitted fabric, and forming gaps by the
 concentration of the film through the surface fastener in a direction from
 the front face to the rear face between the respective constituting yarns.
 Preferably, the method further includes a step of cutting a portion of each
 of the loop which is constituting material of the male engaging element,
 the step being the most typical method for forming the male engaging
 element. The shape of the male engaging element is not limited to the
 hook-shaped male engaging element obtained by the above manufacturing
 method, but the male engaging element may be a so-called mushroom-shaped
 male engaging element obtained by melt cutting a top of a loop for the
 male engaging element woven as described above and providing a hemispheric
 engaging head to a tip end of the cut loop, for example.

DESCRIPTION OF THE PREFERRED EMBODIMENTS
 Preferred embodiments of the present invention will be specifically
 described below based on examples shown in the drawings.
 FIG. 1 is a perspective view of a portion of a first embodiment having a
 woven/knitted fabric structure of a woven surface fastener according to
 the present invention. The first embodiment gives an example wherein the
 woven surface fastener is a female surface fastener having a large number
 of loops formed on a surface of a ground structure. FIG. 1 shows ground
 woven fabric 1, warp 2, weft 3, and monofilament 4 for female engaging
 elements.
 The example shown in FIG. 1 only shows a representative embodiment of the
 invention, and a weaving structure is not limited to the shown example.
 The surface fastener made of fiber of the invention is not limited to a
 woven fabric, but may be formed by warp knitting combining warp yarn and
 weft in-laid yarn or two needle stitch and tricot, for example.
 In the female surface fastener of the present embodiment, the ground
 woven/knitted fabric 1 is formed of a plain weaving structure comprising
 the warp 2 and the weft 3. As the warp 2 which characterizes the present
 invention, monofilament of 30 d is used, and monofilament of 30 d is
 similarly used as the weft 3. In FIG. 1, the weft 3 is ply yarn formed of
 two monofilaments because weft laying of the embodiment is carried out by
 a carrier of a narrow loom, and thus, a double pick is employed wherein
 reciprocating weft laying is carried out for one opening, and a single
 monofilament is used for one weft laying. Therefore, if a normal loom is
 used, each weft 3 is completely formed of a single monofilament.
 In the embodiment, a single monofilament 4 is used as a yarn for female
 engaging elements woven into the ground woven/knitted fabric 1, which
 characterizes the present invention, although a multifilament has
 conventionally been used for the yarn for the female engaging elements.
 The monofilament 4 is woven into the ground woven/knitted fabric 1 while
 forming loops 4a as the female engaging elements. In the embodiment, a
 fineness of the monofilament 4 for the female engaging elements is 30 d.
 Polyester is used for all of the warp 2, the weft 3, and the monofilament 4
 for the female engaging elements 4a in the embodiment. However, it is
 possible to use one of or a combination of kinds of thermoplastic
 synthetic resin material such as polyamide and polypropylene which are
 usually used for the surface fastener of this type. In the embodiment,
 finenesses of the respective yarns are set as described above and
 polyester with a high transparency is used so as to ensure transparency of
 the surface fastener. It is not an only object of the invention to ensure
 transparency, but the invention is based on the premise that monofilament
 is used as yarn for the female engaging elements taking productivity and
 cost efficiency into consideration.
 Because weft 3 is woven in by using the carrier in weaving of the
 embodiment, one yarn reciprocates in the same opening of the warp.
 Therefore, the weft 3 is constantly in a state of ply yarn wherein two
 yarns are put together. Thus, the fineness of the weft 3 will be doubles.
 In the present embodiment, a count of wefts 3 per an inch is in a range of
 57 to 58 which is considerable as compared with usual 52/in. However,
 transparency is ensured because monofilaments as the constituting yarns
 with extremely small finenesses as compared with those of conventional
 yarns are used as described above, and because gaps are ensured between
 warps and wefts in spite of the above-described density of weaving. A
 density of warp in the embodiment is in a range of 120 to 130/in, but the
 densities of weft and warp may be determined based on usage of the surface
 fastener of the invention. Because the fineness is small, the obtained
 surface fastener is extremely thin throughout the fastener.
 Next, a specific example of a structure of woven fabric of the surface
 fastener of the invention woven by using yarns with the above structure
 will be described based on FIG. 1.
 In FIG. 1, monofilament of 30 d is used for warp 2 and weft 3 as
 constituting yarns of the ground woven fabric 1 and for monofilament 4 as
 constituting yarn of the female engaging elements. Because the weft 3 is
 ply yarn as described above, the fineness of the weft 3 is 60 d. A
 structure of the ground woven/knitted fabric 1 is formed of the plain
 weaving structure comprising warp 2 and weft 3. The monofilament 4 is
 woven while forming the loop 4a as the female engaging element every time
 it goes across a warp line w comprising adjacent two warps 2. In this
 case, the loops 4a of the monofilament 4 are successively formed by the
 monofilament 4 passing under a first weft 3, over a second weft 3, then
 under a third weft 3, and going across an adjacent warp line w and passing
 under the next weft 3 as is apparent from FIG. 1. Such a structure of
 woven/knitted fabric is a general weaving structure of a conventional male
 surface fastener. After the monofilament 4 which is the constituting yarn
 of the female engaging elements is woven into three wefts 3, the
 monofilament 4 passes over the warp line w to form a new loop 4a.
 Of course, the weaving structure shown in FIG. 1 is only an example of the
 present invention, and it is also possible to form a loop of the
 monofilament 4 at every other weft 3, for example. In this case, a density
 of the loop increases and an engaging rate between the female engaging
 elements and opposed male engaging elements increases. In this weaving
 structure, it is further desirable to form each loop 4a by the
 monofilament 4 passing over the warp line w comprising two warps 2 in a
 zigzag manner in order to direct the loops 4a in various directions.
 The woven fabric woven as described above is thermally set on the loom
 according to a general process to fix a structure of the ground woven
 structure and a shape of the loops 4a. Then, resin is coated on the rear
 side to secure base portions of the loops 4a to the ground woven fabric 1.
 In order to ensure flexibility and transparency in addition to stability
 of the loop shapes, it is desirable to use resin material which is highly
 adhesive to the respective constituting yarns and which is of the same
 kind as the respective constituting yarns, to coat as small amount as
 possible of the resin, and to concentrate the resin on contact portions of
 projecting base portions of the loops 4a with the ground wove fabric 1.
 In order to apply synthetic resin material to the woven surface fastener as
 described above in the embodiment, a heating area 11 is provided in the
 vicinity of a cloth fell portion of a loom 10, as shown in FIG. 2. A
 roller coating portion 12 which has a scraper 13 and coats synthetic resin
 material on the back face of the surface fastener is provided downstream
 of the heating area 11. An air nozzle 14 is disposed downstream of the
 roller coating portion 12 to be adjacent to the roller coating portion 12
 and to face the rear face of the surface fastener. A tape loom is usually
 used as the loom 10, but a normal loom may be used.
 A woven shape of the surface fastener woven by the loom 10 and having the
 above structure is fixed by thermally setting in the heating area, and the
 fastener is coated on its rear face with the synthetic resin diluted with
 solvent through a coating roller 12a of the roller coating portion 12. A
 thickness of the coat is adjusted by the scraper 13, thereby forming a
 thin film over the entire rear face of the surface fastener. When the
 surface fastener reaches a position where the air nozzle 14 is disposed in
 this state, air is sprayed on the thin film in a direction from the rear
 face side to the front face side to the surface fastener. By this air, the
 thin film formed in gaps between the respective constituting yarns 2, 3,
 and 4 is fractured to be gathered toward crossings of the respective
 constituting yarns 2, 3, and 4, thereby locally bonding the crossings and
 allowing the gaps to be open.
 Thus, the synthetic resin material concentrates on the respective crossings
 of warp 2 and weft 3 and monofilament 4 for the female engaging elements
 4a as constituting yarns of the surface fastener, and the synthetic resin
 material bonds the constituting yarns intensively at the crossings.
 Therefore, The loops 4a as the female engaging elements are firmly secured
 without getting out of shape. Furthermore, because gaps are formed between
 the respective constituting yarns from the front face to the rear face,
 and because all the monofilaments 2, 3, and 4 are transparent, the rear
 side of the surface fastener can be further clearly seen through from the
 front side.
 By ensuring transparency in this manner, if the surface fastener of the
 embodiment is directly mounted to a portion of a bag or an outerwear where
 various designs or letters are provided, the designs or letters can be
 seen through from the front side of the fastener in the embodiment. It is
 also possible to provide logotypes, various designs, or letters, or
 colored versions of them to the back face of the surface fastener. On the
 other hand, because the conventional surface fastener lacks transparency,
 a color has to be directly applied to a front face of the fastener where
 the engaging elements are formed. In this case, because the color comes
 out or the engaging elements are deformed due to repeated use, a
 difference may be generated in clearness of the designs on the fastener
 and designs around the fastener, or the designs on the fastener may
 deviate from the designs around the fastener. In this point, according to
 the invention, because the designs and the like are applied to a face of
 an article to which the surface fastener is mounted and which is on the
 rear side of the fastener, the above problems are not generated.
 FIG. 3 shows a male surface fastener of a second embodiment of the
 invention. In this embodiment, both warp 2 and weft 3 of the ground
 knitted fabric 1 are monofilaments of 30 d similarly to the above first
 embodiment. A fineness of a monofilament 5 of a constituting yarn for male
 engaging elements 5a is 150 d, and this fineness is extremely large as
 compared with those of other yarns. However, it would be understood that
 the fineness is very small as compared with a fineness of a monofilament
 for conventional male engaging elements which is in a range of 200 d to
 350 d.
 In the present embodiment, the fineness of the monofilament 5 for the male
 engaging elements 5a is larger than those of the other constituting yarns
 2 and 3 as described above so as to ensure an engaging force, but may be
 properly determined according to usage. However, it is desirable that the
 fineness of the monofilament 5 is equal to or smaller than 150 d to ensure
 transparency of the surface fastener as a product, and it is desirable
 that the fineness of the monofilament 5 is equal to or greater than 100 d
 to ensure a necessary engaging force. Material of the respective yarns
 used in this embodiment is polyester having transparency similarly to the
 first embodiment.
 FIG. 4 shows a self engaging type of surface fastener of a third embodiment
 of the invention, wherein male and female engaging elements 4a, 5a are
 mixed on the same surface of a ground woven fabric 1. In this embodiment,
 monofilaments of both warp 2 and weft 3 of the ground woven fabric 1 are
 30 d similarly to the above first embodiment. A monofilament 4 as a
 constituting yarn of the female engaging elements 4a is 30 d, and a
 monofilament 5 as a constituting yarn streak of the male engaging elements
 5a is 150 d similarly to the above embodiment. In this embodiment, a
 fineness of the monofilament 5 of the male engaging elements 5a is larger
 than those of the other constituting yarns 2, 3, and 4 as described above
 for the same reason as that in the above embodiment.
 Thus, the woven structure of the present embodiment is substantially the
 same as those of the above first and second embodiments, but is different
 from the first and second embodiments only in that the loops 4a which are
 the female engaging elements and the loops which are the male engaging
 elements 5a are alternately disposed in a weaving width direction. In
 other words, every other monofilament 4 for the female engaging elements
 is replaced by the monofilament 5 for the male engaging elements 5a, and
 therefore, woven structures as a whole of both the monofilaments 4 and 5
 are the same as those of the above first and second embodiments.
 However, in this embodiment, finenesses of the monofilament 4 for the
 female engaging elements 4a and the monofilament 5 for the male engaging
 elements 5a are different from each other as described above, and in
 addition, the male engaging elements 5a are finally provided with such
 shapes to be engaged with the female engaging elements 4a. In this
 invention, it is unnecessary that the male engaging elements 5a have
 special shapes and functions which are different from those of the
 conventional male engaging elements. The male engaging element 5a may be a
 normal hook obtained by cutting a portion of the loop for the male
 engaging element 5a, or may be a so-called mushroom-shaped engaging
 element obtained by melt cutting an upper end of the loop and providing a
 hemispheric engaging head to a tip end of the cut loop.
 After the loop woven fabric with the above weaving structure is woven,
 thermal setting and forming of a thin film on a rear face of the woven
 fabric are carried out similarly to the first embodiment. Then, according
 to a general process, the portion of each the loop for the male engaging
 element 5a is cut to form a hook 5a as the male engaging element. In this
 embodiment, flexibility and transparency are ensured in the surface
 fastener obtained similarly to the first embodiment, and the surface
 fasteners with the same structures can be joined with each other with a
 necessary engaging strength by pushing the fasteners against each other
 with their engaging element surfaces facing each other, and can be easily
 peeled from each other.
 FIG. 5 shows a fourth embodiment having a woven fabric structure of a woven
 surface fastener according to the invention, wherein like reference
 numerals and/or letters are allocated to constituting elements
 substantially the same as those of the above embodiments. In the present
 embodiment, a weaving structure of the woven surface fastener is the same
 as that in the first embodiment and will not be described specifically.
 The present embodiment is the same as the above embodiments in a point that
 a monofilament 4 is used as a yarn for female engaging elements 4a. In
 addition, a point which characterizes this embodiment best is that the
 monofilament 4 has a self-torsion property. According to the embodiment,
 as shown in an enlarged scale in FIG. 6, the monofilament 4 has a
 sectional triangular shape. Because of this sectional shape, torsion is
 naturally generated in the monofilament 4 due to friction applied to edge
 lines and forming mechanism of the loops 4a when the monofilament 4 is
 woven into the ground structure in weaving of the ground woven fabric 1 by
 using warp 2 and weft 3 as constituting yarns of the ground structure. The
 torsion concentrates on a rising base end portion of the loop 4a. Because
 of this torsion, the loops 4a of the monofilament 4 are firmly woven into
 the ground woven fabric 1 in a state wherein shapes of the loops 4a are
 stable.
 The monofilament 4 has the sectional triangular shape in this embodiment,
 but may have any sectional shape which allows the monofilament 4 to
 exhibit the above torsion property. Usually, it is desirable that the
 sectional shape is a polygon having three or more angles. The torsion
 property depends not only on the shape of the monofilament 4, but torsion
 is generated in conjugate structure fiber obtained by compound spinning
 normal fiber material with high heat-shrinking property and fiber material
 with low heat-shrinking property arranged side by side when heated.
 Typical combinations of fiber material are a combination of polyester with
 a low drawing ratio and polyester with a high drawing ratio, and a
 combination of nylon 6 and nylon 66. It is desirable to select and combine
 kinds of synthetic resin material which have affinity with each other and
 belong to the same group.
 On the other hand, a manufacturing process of the surface fastener of this
 type necessarily includes a finishing step including heating before
 obtaining a final product. Therefore, when the yarn which is crimped as a
 result of heating is used, the yarn is crimped in the finishing step
 without a special heating step. The torsion is generated in the rising
 base end portion of the loop of the monofilament 4, and the monofilament 4
 firmly holds the warp 2 and/or weft 3 of the ground woven fabric 1 in a
 state wherein a shape of the monofilament 4 resulted from the torsion is
 maintained. A degree of torsion at this time can be easily determined by
 adjusting a ratio of materials to be combined.
 Of course, a weaving structure shown here is only an example of the
 invention, and it is possible to form a loop 4a of monofilament 4 at every
 other weft 3, and in this case, a loop density is increased, thereby
 increasing the engaging rate of the female engaging elements 4a with the
 opposed male engaging elements 5a. In this weaving structure, it is
 further desirable to form the loops 4a such that the monofilament 4 passes
 over the warp line w including two warps 2 in a zigzag manner so as to
 direct the loops 4a in various directions.
 Thus, because the monofilament 4 is rubbed by the warp 2 and weft 3 and is
 carried in the weaving width direction in forming of the loops 4a, the
 torsion property is automatically applied to the monofilament 4. A shape
 of the monofilament 4 at this time is shown in FIG. 6. This torsion
 property is not necessarily generated in forming all the loops, and thus,
 all the formed loops 4a are not necessarily directed in the same
 direction, as shown in FIG. 5. In this point, shapes of a part of the
 loops 4a are not stably maintained.
 Therefore, in the embodiment, the woven fabric woven in the above manner is
 thermally set on the loom according to the general process so as to fix
 the shapes of the loops 4a. Then, rein is coated on the rear face side and
 the base portions of the loops 4a are secured to the ground woven fabric
 1. In order to ensure flexibility and transparency in addition to
 stabilizing the loop shapes, material which is highly adhesive to the
 respective constituting yarns and is of the same kind as the yarns is used
 as resin material, an amount of the resin material to be coated is set at
 as small value as possible, and the resin material is concentrated on
 portions where the projecting base portions are in contact with the ground
 woven fabric 1.
 As described above, because the synthetic resin material is concentrated on
 the crossings of the warp 2 and weft 3 and the monofilament 4 for the
 female engaging elements 4 as the constituting yarns of the surface
 fastener are bonded to each other intensively at the crossings, the loops
 4a which are the female engaging elements do not get out of shape.
 Furthermore, because gaps are formed to penetrate the ground woven fabric
 from the front face to the rear face between the respective constituting
 yarns and all the monofilaments 2, 3, and 4 are transparent, the rear face
 side of the surface fastener can be further clearly seen through from the
 front face.
 Therefore, in this embodiment, logotypes, various designs, or letters, or
 colored versions of them, for example, are provided to the rear face of
 the surface fastener. On the other hand, because the conventional surface
 fastener lacks transparency, a color has to be directly applied to a face
 of the fastener where the engaging elements are formed. In such a case,
 because the color comes out or the engaging elements are deformed due to
 repeated use, a difference may be generated in clearness of the designs on
 the fastener and designs around the fastener, or the designs on the
 fastener may deviate from the designs around the fastener. In this point,
 according to the invention, because the designs and the like are applied
 to a face of an article to which the surface fastener is mounted and which
 is on the rear side of the fastener, the above problems are not generated.
 FIG. 7 shows a self engaging type of surface fastener of a fifth embodiment
 of the invention, wherein male and female engaging elements 4a, 5a are
 mixed on the same surface of a ground woven fabric 1. In this embodiment,
 finenesses of monofilaments of both warp 2 and weft 3 of the ground woven
 fabric 1 are 30 d similarly to the above first embodiment. A fineness of
 monofilament 4 as a constituting yarn of the female engaging elements 4a
 is 30 d, and a fineness of monofilament 5 as a constituting yarn of the
 male engaging elements 5a is 150 d. The fineness of the monofilament 5 of
 the male engaging elements 5a is extremely large as compared with those of
 the other yarns, but is very small as compared with a fineness of
 monofilament for conventional male engaging elements in a range of 200 d
 to 350 d.
 In the present embodiment also, the fineness of the monofilament 5 for the
 male engaging elements 5a is larger than those of the other constituting
 yarns 2, 3, and 4 as described above so as to ensure an engaging force,
 but may be properly determined according to usage. However, it is
 desirable that the fineness of the monofilament 5 is equal to or smaller
 than 150 d to ensure transparency of the surface fastener as a product,
 and it is desirable that the fineness of the monofilament 5 is equal to or
 greater than 100 d to ensure a necessary engaging force. Material of the
 respective yarns used in the embodiment is polyester having transparency
 similarly to the first embodiment. Thus, the woven fabric structure of the
 embodiment is substantially the same as that of the above third embodiment
 shown in FIG. 4.
 However, in this embodiment, in addition to that the finenesses of the
 monofilament 4 for the female engaging elements 4a and the monofilament 5
 for the male engaging elements 5a are different from each other, it is
 unnecessary that the monofilament 5 for the male engaging elements 5a has
 a special shape or function and the monofilament 5 may be one used for
 normal hooks and having a circular shape in section, while the loops 4a as
 the female engaging members have a self torsion property as described
 above. This is because formation of the hooks described later becomes
 difficult if the monofilament 5 for the male engaging elements 5a is
 provided with the self torsion property similarly to the monofilament 4
 for the female engaging elements 4a. Therefore, if the male engaging
 element is a so-called mushroom-shaped engaging element obtained by melt
 cutting an upper end of the loop and providing a hemispheric engaging head
 to a tip end of the cut loop, by generating torsion in the base end
 portions of the loops for the male engaging elements projecting from the
 ground woven fabric 1 as described above, the loops can be firmly mounted
 to the ground woven fabric 1. Therefore, it is possible to apply self
 torsion property to the monofilament 5 for the male engaging elements.
 After the loop woven fabric having the above weaving structure is woven,
 the woven fabric is thermally set and formed at its rear face with a thin
 film similarly to the first embodiment. Then, according to the general
 process, a portion of each loop for the male engaging element 5a is cut to
 form a hook 5a which is the male engaging element. In the present
 embodiment, flexibility and transparency are ensured in the surface
 fastener similarly to the first embodiment, and the surface fasteners with
 the same structure can be joined to each other with a necessary engaging
 strength by pushing the fasteners against each other with their engaging
 element faces facing each other, and can be easily peeled from each other.
 Although the preferable embodiments of the present invention have been
 described above, the invention is not limited to the embodiments, but it
 is possible to set the finenesses of warp and weft of the ground
 woven/knitted fabric at normal values when transparency and flexibility
 are not required, and also a weaving density may be properly selected.