Reflective yarn and method of producing the same

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates, in general, to a reflective yarn and a method of producing the same and, in particular, to a reflective yarn comprising 5 to 25 wt % of spherical glass beads vacuum-metalized with materials having reflective function, or if necessary, further comprising glass beads not vacuum-metalized with materials having reflective function and/or pearl beads, and a method of producing the reflective yarn comprising the steps of vacuum-metalizing materials having reflective function on surfaces of spherical glass beads; melt-spinning the resulting glass beads with synthetic resin having fiber formative function, or melt-spinning the resulting glass beads and the synthetic resin in conjunction with 10 wt % or less of non-metalized glass beads and/or pearl beads to produce monofilaments or hollow fibers; and doubling monofilaments or hollow fibers to produce the reflective yarn. The spherical glass beads have a bead size of 10 to 50 μm and are vacuum-metalized with materials having reflective function such that ¼ to ½ of surface areas of glass beads are vacuum-metalized.

[0003] 2. Description of the Prior Art

[0004] Generally, materials having reflective function are widely used in safety applications for preventing accident and securing a safe condition, and demands for these materials have rapidly grown.

[0005] For example, when a traffic policeman or a street sweeper works at night, or when an old person or child is exposed to vehicles at night, it is difficult for a driver to recognize them, and so a loss of lives may be readily caused. To reduce the danger, therefore, materials having reflective function are applied to various traffic signs, miscellaneous goods such as sportswear, sporting goods, and bags, and military recognition signs.

[0006] Meanwhile, various studies have been made of materials having a high reflective index as well as materials reflecting light. For example, reflective sheet materials are commercially and widely used. However, reflective material with fiber formative function is not commercially produced, and so the reflective material has hardly been applied to slit threads or textiles.

[0007] Accordingly, the reflective sheet material as illustrated in FIGS. 1 and 2 should be cut at regular intervals and mixed, doubled, or drawn with traditional slit threads so as to be used as a reflective fiber.

[0008] Reflective textiles are produced by coating an aluminum paste coating layer 70 as a reflective film on any one side of a thin synthetic resin sheet 60, as shown in FIG. 1. However, the reflective textiles have disadvantages in that the reflective index and reflection brightness are practically weak because irregular reflection occurs through the reflective film, and so reflective textiles are not suitable to be commercially used, and reflection efficiency is rapidly reduced and color fastness to washing is low because the aluminum paste coating layer 70 is easily removed from the synthetic resin sheet or easily damaged.

[0009] Furthermore, reflective textiles may be produced by coating an aluminum paste coating layer 70 as a reflective film on any one side of a thin synthetic resin sheet 60 and coating a mixture of transparent polyurethane and glass beads 40 with a bead size of 10 to 50 μm on the aluminum coating layer 70, as shown in FIG. 2. However, the reflective textiles have disadvantages in that the synthetic resin sheet can be limitedly applied to clothes, have a poor texture and color fastness to washing, are reduced in workability, and are difficult to apply to embroidery yarn because the synthetic resin sheet is made of a hard material such as polyethylene terephthalate or polyvinyl chloride, even though recurrent reflection can be feasible and reflection efficiency is good.

[0010] Synthetic resin fabric may be used instead of the synthetic resin sheet 60. However, the synthetic resin fabric is also disadvantageous in that texture, workability, and color fastness to washing are poor, and the synthetic resin fabric cannot be widely applied to various applications even though reflection efficiency is good.

[0011] In detail, the aluminum paste coating layer 70 is coated on any one side of the thin synthetic resin sheet 60 or the synthetic resin fabric as the reflective film, the mixture of transparent polyurethane or an adhesive and glass beads 40 with a bead size of 10 to 50 μm is coated on the aluminum paste coating layer 70 to produce the reflective textiles, and the reflective textiles thus produced are longitudinally cut in such a way that the width of the reflective textiles is 0.25 to 0.37 mm for the thin reflective textiles and 3 to 5 mm for the thick reflective textiles, so as to be used as a slit thread. However, the resulting reflective textiles are readily broken because of weak tensile strength, and even if they are doubled or drawn, tensile strength is improved but texture is poorer than that of fiber. In addition, the resulting reflective textiles are used as tapes or plates, but not as textiles. Strictly speaking, therefore, such reflective textiles cannot be included in textiles. Furthermore, the reflective textiles are disadvantageous in that the reflective textiles should be woven in only a predetermined direction because light beams are reflected against only one side of the reflective textiles, and an omnidirectional reflection is hard to realize even though recurrent reflection is feasible.

SUMMARY OF THE INVENTION

[0012] Therefore, it is an object of the present invention to provide an omnidirectional reflective yarn, which has a fiber formative function and simultaneously realizes an omnidirectional reflection, has a good texture and an improved workability, can be applied to mechanical embroidery, computer embroidery, and sewing because the reflective yarn can be used as an embroidery yarn, can be easily washed and has an excellent color fastness to washing, is not changed in physical properties after washing, can be applied to various applications and can be produced in commercial quantity, and has a low price.

[0013] It is another object of the present invention to provide a method of inexpensively producing such omnidirectional reflective yarns in commercial quantity.

[0014] Based on the present invention, the above objects of the present invention can be accomplished by provisions of a reflective yarn comprising 5 to 25 wt % of spherical glass beads vacuum-metalized with materials having reflective function, or if necessary, further comprising glass beads not vacuum-metalized with materials having reflective function and/or pearl beads; and a method of producing the reflective yarn comprising the steps of vacuum-metalizing materials having reflective function on surfaces of spherical glass beads with a bead size of 10 to 50 μm such that ¼ to ½ of surface areas of glass beads are vacuum-metalized; melt-spinning the resulting glass beads with synthetic resin having fiber formative function, or melt-spinning 5 to 25 wt % of resulting glass beads and the synthetic resin in conjunction with glass beads not metalized with materials having reflective function and/or pearl beads to produce monofilaments or hollow fibers; and doubling monofilaments or hollow fibers to produce the reflective yarn. The spherical glass beads have a bead size of 10 to 50 μm and are vacuum-metalized with materials having reflective function such that ¼ to ½ of surface areas of glass beads are vacuum-metalized.

[0015] Therefore, the reflective yarn of the present invention is advantageous in that it has fiber formative function and simultaneously realizes an omnidirectional reflection, has a good texture and an improved workability, and can be applied to mechanical embroidery, computer embroidery, and sewing, because the reflective yarn can be used as an embroidery yarn. Other advantages of the present invention are that washing of the reflective yarn can be easily conducted, and it has excellent color fastness to washing, physical properties of the reflective yarn are not changed after washing, the reflective yarn can be applied to various applications and can be produced in commercial quantity, and its price is low.

BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The above and other objects, features and other advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which:

[0017]
FIG. 1 schematically illustrates a mechanism of reflection of light beams in a conventional reflective yarn;

[0018]
FIG. 2 schematically illustrates a mechanism of reflection of light beams in slit thread or fabric produced using the conventional reflective yarn;

[0019]
FIGS. 3 and 4 schematically illustrate a mechanism of reflection of light beams in an omnidirectional reflective yarn according to the present invention; and

[0020]
FIG. 5 schematically illustrates a mechanism of reflection of light beams in the omnidirectional reflective yarn, hollow yarn, according to the present invention.

DETAILED DESCRIPTION OF THE INVENTION

[0021] The present invention provides an omnidirectional reflective yarn, comprising a synthetic yarn produced using synthetic resin with fiber formative function by a melt-spinning process; and 5 to 25 wt % of spherical glass beads with a bead size of 10 to 50 μm, ¼ to ½ of surface area of which is vacuum-metalized with material having reflective function. If necessary, the omnidirectional reflective yarn may further comprise 10 wt % or less of non-metalized glass beads and/or pearl beads. The non-metalized glass beads are not vacuum-metalized with material having a reflective function.

[0022] Furthermore, the present invention provides a method of producing an omnidirectional reflective yarn, comprising the steps of vacuum-metalizing a material having reflective function on the surfaces of spherical glass beads with a bead size of 10 to 50 μm such that ¼ to ½ of surface areas of the spherical glass beads is vacuum-metalized with the material having reflective function; melt-spinning the resulting glass beads with synthetic resin having a fiber formative function, or if necessary, melt-spinning the resulting glass beads and the synthetic resin in conjunction with 10 wt % or less of non-metalized glass beads and/or pearl beads to produce monofilaments or hollow fibers; and doubling the monofilaments or the hollow fibers.

[0023] Metalized glass beads 20, a part of the surface of which is vacuum-metalized with a reflective film, should take a shape of a sphere so that irregular reflection and recurrent reflection occur in a slit thread produced using metalized glass beads 20, thereby an effect of omnidirectional reflection is sufficiently achieved. In addition, it is preferable that glass beads 40, a part of the surface of which is not vacuum-metalized with the reflective film, take a shape of sphere so as to sufficiently achieve the effect of omnidirectional reflection.

[0024] Glass beads 20 and 40 useful in the present invention are 10 to 50 μm in bead size. For example, when the bead size is less than 10 μm, recurrent reflection and irregular reflection effects are good, glass beads are easily mixed with synthetic resin because glass beads are sufficiently compatible with the synthetic resin having fiber formative function, and dispersibility and lubricating ability are not largely reduced. However, it is difficult and not economical to produce glass beads with low bead size while the glass bead maintains a spherical shape.

[0025] On the other hand, when the bead size is more than 50 μm, the slit thread produced using glass beads is too thick, glass beads are not sufficiently mixed with the synthetic resin with the fiber formative function because glass beads are not sufficiently compatible to the synthetic resin with the fiber formative function, and dispersibility and lubricating ability are greatly reduced, and thus it is difficult to produce yarn using glass beads.

[0026] Illustrative, but non-limiting components of the glass bead include 10 to 15% of TiO2 (titanium dioxide) and BaO (barium oxide) and 85 to 90% of SiO2 (silicon oxide).

[0027] The reflective film may be made of any materials which can reflect light. In consideration of reflection efficiency, specific weight, ease of metalization, and metalization property, it is most preferable to use aluminum as the material of the reflective film.

[0028] Additionally, it is preferable that a metalized part 22 of metalized glass beads 20 comprise ¼ to ½ of the surface area of whole glass beads. For example, when the surface area of the metalized part is less than ¼ of a whole glass beads surface area, a reflective index is reduced because an amount of light reflected as recurrent reflection is small, and yarn cutting easily occurs because a great amount of glass beads are used to obtain the sufficient reflective index, because mostly only irregular reflection occurs. Furthermore, the slit thread produced using the glass bead has poor texture and it is not economical to produce the glass bead.

[0029] On the other hand, when the surface area of the metalized part is more than ½ of whole glass beads surface area, the reflective film cannot be easily metalized, reflective index is reduced because an amount of recurrent reflection of light is small, and the expense to metalize the glass bead is large, and so the glass bead having a metalized part of more than ½ of whole glass beads surface area is not economical to use in production of the slit thread.

[0030] The reflective film is produced according to various Vacuum Metalization processes such as Vacuum Metalization, Ion Plating, Sputtering, Vapor Plating, Evaporation, Ion-beam, Molecular Beam Epitaxy, and ARE. As will be appreciated by those skilled in the art, the reflective film, in particular, aluminum reflective film can be easily formed on glass beads.

[0031] For example, polyethylene terephthalate (PET) sheet is coated with polyethylene to a thickness of 2 to 25 μm and then a silane silicone coating agent in an amount of 2 to 5 g/m2. After that, glass beads are uniformly dispersed on the resulting PET sheet with the use of a vibrator. Thereafter, glass beads are sunk by a heat roller to ¾ to ½ volume into the resulting PET sheet, and aluminum is metalized on the glass beads and the PET sheet.

[0032] Metalized glass beads 20 thus produced have a specific weight of 4.2 and a reflective index of 1.93±0.02 in 100%.

[0033] The metalized glass beads 20 are melt-spun with synthetic resin 30 having fiber formative function, or if necessary, melt-spun in conjunction with the synthetic resin and 10 wt % or less of non-metalized glass beads 40 and/or pearl beads 50 to produce monofilaments or hollow fibers.

[0034] It is effective to use 5 to 25 wt % of metalized glass beads 20 during production of monofilaments or hollow fibers. For example, when an amount of metalized glass beads 20 is less than 5 wt %, reflection effect cannot be sufficiently obtained. On the other hand, when the amount is more than 25 wt %, the reflection effect is not further increased with increasing the amount of metalized glass beads 20.

[0035] In addition, it is preferable that total amount of metalized glass beads 20, and non-metalized glass beads 40 and/or pearl beads 50 is not more than 35 wt %. When the total amount is more than 35 wt %, formation of yarn cannot be easily conducted and yarn cutting occurs during a spinning process because beads have a large difference in physical properties in comparison with the synthetic fiber 30 having fiber formative function, and the slit thread produced using the beads becomes poor in physical properties such as tensile strength.

[0036] A dispersing agent and a softner are used so as to prevent reduction of dispersibility of glass beads in the synthetic resin 30 during a melt-spinning step because metalized glass beads 20, and non-metalized glass beads 40 are incompatible with the synthetic resin 30 having the fiber formative function, and it is difficult to produce slit thread using glass beads due to poor softness.

[0037] In other words, the metalized glass beads 20 have 3 to 5 times higher specific weight than the synthetic resin 30 having fiber formative function, i.e. the specific weight is 4.2, and so 0.2 to 0.5 wt % of softner is used for uniformly mixing glass beads with the synthetic resin, providing softness to the synthetic resin, and improving softness of the slit thread produced with the use of glass beads and the synthetic resin. Furthermore, 0.2 to 0.5 wt % of dispersing agent is used for uniformly mixing metalized glass beads 20 with the synthetic resin 30 having the fiber formative function in an extruder.

[0038] Any softner and dispersing agent generally used in the art may be used to produce the slit thread, and it is most preferable that DOP (dioctyl phthalate) is used as the softner and Ca antiadditive is used as the dispersing agent. If an amount of the softner or the dispersing agent deviates from a range of 0.2 to 0.5 wt %, desired effect becomes poor or effect of the softner or the dispersing agent is not greatly improved, and so use of the softner or the dispersing agent is not economical, and physical properties of yarn produced using glass beads and the synthetic fiber are reduced.

[0039] Furthermore, 0.2 to 0.5 wt % of various performance improvers such as UV shielding agent, antistatic agent, aromatic agent, odor removing agent, and deodorant may be additionally used to produce the slit thread in order to improve various physical properties of the slit thread, and improve economic efficiency.

[0040] According to the present invention, when metalized glass beads 20 are added to the synthetic resin, reflection effect is improved, and in particular, non-metalized glass beads 40 and pearl beads 50, or combination thereof may be added to the synthetic resin in order to much improve the reflection effect.

[0041] It is preferable that non-metalized glass beads 40 comprise the same glass beads as the metalized glass beads 20, that is to say, the non-metalized glass beads 40 are spherical beads with a bead size of 10 to 50 μm.

[0042] When the non-metalized glass beads 40 are added to the synthetic resin, light beams are refracted through the non-metalized glass beads 40. At this time, when the refracted light is incident on non-metalized part 21 of the metalized glass bead 20, recurrent reflection occurs by a metalized part 22 of the metalzied glass bead 20, thereby a slit thread has an improved reflection effect.

[0043] As for the pearl bead 50, it is used as a reflector with diameter of 10 to 50 μm. The pearl bead 50 has poorer reflection brightness than the metalized glass bead 20. However, when it is used in conjunction with the metalized glass bead 20, it can show various colors by combination of various pigments, as well as having a reflection effect.

[0044] For example, the pearl bead can sufficiently show combined colors of red, yellow, blue, black, and white etc., and so it is useful in clothes, bags, and footwear applications. It is preferable that the amount of the non-metalized glass bead 40 and/or the pearl bead 50 additionally applied to the synthetic resin in addition to 5 to 25 wt % of metalized glass bead 20 is not more than 10 wt %. When the amount is more than 10 wt %, reflection improving effect is reduced.

[0045] After production of monofilaments or hollow fibers, the monofilaments or the hollow fibers are doubled to produce the omnidirectional reflective yarn of the present invention. Light beams reflected in a type of recurrent reflection or irregular reflection in the monofilament or the hollow filament are again reflected in other monofilaments or hollow filaments in the type of recurrent reflection or irregular reflection, thereby an omnidirectional reflection effect is realized.

[0046] A better understanding of the present invention may be obtained in light of the following examples which are set forth to illustrate, but are not to be construed to limit the present invention.

EXAMPLE 1

[0047] To produce polypropylene (PP) yarn having an omnidirectional reflection function, ⅓ of the surface of glass beads with an average bead size of 40 μm and a bead size distribution of 10 to 50 μm was vacuum-metalized with aluminum to produce a metalized glass bead. Polypropylene resin was added in conjunction with 0.5 wt % of dioctylphthalate based on the polypropylene resin to a stirrer, then stirred at rotation speed of 100 rpm for 30 min to form a thin oil film on a surface of polypropylene resin. After that, 15 wt % of metalized glass beads were added to the stirrer and stirred at a rotation speed of 100 rpm for 30 min. At this time, metalized glass beads were uniformly distributed on the surface of polypropylene resin by oil components of the oil film formed on the surface of polypropylene resin. The resulting resin comprising glass beads of the present invention may be melt-spun without a traditional master batch. The production cost of polypropylene yarn is low because it is not necessary to produce the master batch and degradation of the resin usually occurring in extruding for producing the master batch is prevented, and so a transparent slit thread can be obtained. The resulting resin comprising glass beads was melt-spun in an extruder at 210E□ at a winding speed of 600 to 800 m/min to produce an undrawn yarn of 430 deniers/18 filaments, then drawn 2.3 times longer by use of a drawing machine to produce a drawn yarn of 180 deniers with tenacity of 3 g/denier.

EXAMPLE 2

[0048] To produce a polyester (PET) yarn having omnidirectional reflection function, polyethylene terephthalate resin with an intrinsic viscosity of 0.77 and metalized glass beads of example 1 were sufficiently dried in two different driers, respectively, for 10 hours so that moisture contents reached 25 ppm or lower. Dried metalized glass beads were added through a side feeder to the extruder in an amount of 15 wt % while the dried polyethylene terephthalate resin was discharged from the extruder at 285□ at the winding speed of 600 to 800 m/min to produce undrawn yarn of 450 deniers/18 filaments. After that, the undrawn yarn was drawn 2.1 times longer by use of the drawing machine to produce a drawn yarn of 200 deniers with tenacity of 3.0 g/denier.

EXAMPLE 3

[0049] To produce a polyester (PET) yarn having the omnidirectional reflection function, polyethylene terephthalate resin with intrinsic viscosity of 0.77 and metalized glass beads were sufficiently dried in two different driers, respectively, for 10 hours so that moisture contents reached 25 ppm or lower. Dried metalized glass beads were added through a side feeder to the extruder in an amount of 15 wt % while the dried polyethylene terephthalate resin was discharged from the extruder at 285□, then drawn 2.1 times longer by use of a two step pair hot godet roller to produce a drawn yarn of 200 deniers with tenacity of 3.0 g/denier.

EXAMPLE 4

[0050] To produce a polyamide (nylon) yarn having the omnidirectional reflection function, dried metalized glass beads were added through the side feeder to the extruder in the amount of 15 wt % while nylon chips with a relative viscosity of 2.4 were discharged through the extruder at 265□ to produce a polyamide yarn of 180 deniers/18 filaments.

EXAMPLES 5 TO 8

[0051] Procedures of examples 1 to 4 were repeated except that non-metalized glass beads were additionally added to synthetic resin in the amount of 5 wt %, thereby synthetic yarn was produced. The synthetic yarn thus produced had an improved reflection effect, and the reflection effect of light was controlled by varying the amount of metalized and/or non-metalized glass beads to produce various synthetic yarns according to consumer's needs.

EXAMPLE 9

[0052] An undrawn yarn melt-spun according to the same procedure as example 1 was drawn by use of the drawing machine and simultaneously cut to produce staple fibers having mono denier of 7 and length of 52 mm. Then, staple fibers thus produced were heat treated with the use of a calender roll at 145□ to produce non-woven fabrics with a thickness of 0.13 mm. Alternatively, the non-woven fabrics were produced with the use of staple fibers according to a conventional heat flame process, i.e. conventional fiber production process, and the non-woven fabrics were useful to replace PET based rigid reflective clothes and had a good workability. The non-woven fabrics are advantageous in that they are suitable to use as a very soft fiber, in comparison with a conventional PET sheet (whose two sides are coated with aluminum reflector and glass beads, respectively, so that the PET sheet has a recurrent reflection function), or a conventional PVC sheet, and so the non-woven fabrics can be extensively applied to various applications such as safety clothing or safety labels.

EXAMPLES 10 TO 18

[0053] Procedures of examples 1 to 9 were repeated except that non-metalized glass beads were uniformly mixed with pearl beads in a weight ratio of 70:30 and added through the side feeder in conjunction with yellow pigment master chips to the extruder in a proportion of 2 wt %, to produce a yarn-died synthetic yarn with yellow and pearl colors.

[0054] As described above, the present invention provides a reflective yarn comprising 5 to 25 wt % of spherical glass beads vacuum-metalized with materials having reflective function, or if necessary, further comprising glass beads not vacuum-metalized with materials having reflective function and/or pearl beads. The spherical glass beads have a bead size of 10 to 50 μm and are vacuum-metalized with materials having reflective function such that ¼ to ½ of surface areas of glass beads is vacuum-metalized. In addition, according to the present invention, provided is a method of producing the reflective yarn comprising the steps of vacuum-metalizing materials having reflective function on surfaces of spherical glass beads with the bead size of 10 to 50 μm such that ¼ to ½ of surface areas of glass beads is vacuum-metalized; melt-spinning the resulting glass beads with synthetic resin having fiber formative function, or melt-spinning the resulting glass beads and the synthetic resin in conjunction with glass beads not metalized with materials having reflective function and/or pearl beads to produce monofilament; and doubling monofilaments to produce the reflective yarn.

[0055] Therefore, the reflective yarn of the present invention is advantageous in that it has fiber formative function and simultaneously realizes an omnidirectional reflection, has a good texture and an improved workability, and can be applied to mechanical embroidery, computer embroidery, and sewing because the reflective yarn can be used as an embroidery yarn. Other advantages of the present invention are that washing of the reflective yarn can be easily conducted and it has an excellent color fastness to washing, physical properties of the reflective yarn are not changed after washing, the reflective yarn can be applied to various applications and can be produced in commercial quantity, and its price is low.

[0056] The present invention has been described in an illustrative manner, and it is to be understood that the terminology used is intended to be in the nature of description rather than of limitation. Many modifications and variations of the present invention are possible in light of the above teachings. Therefore, it is to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described.

Reflective yarn and method of producing the same

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