JP2010099268A - Dental floss and method for manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a dental floss and a method for manufacturing the same, using an extra fine fiber multi-filament, having excellent flossing effect and use feeling and hardly causing scuffing and breakage of yarn. <P>SOLUTION: In this dental floss, a sheath yarn Y mainly composed of heat fused yarn and having a higher average single yarn fineness than a core yarn X and a higher heat contraction rate than the core yarn X is wound spirally with spaces to make a number of turns of 50-500 T/m in the periphery of the core yarn X formed of an extra fine fiber multi-filament with an average single yarn fineness of 1.1 dtex or smaller, and the core yarn X and the sheath yarn Y are partially fixed to each other by heat fusion. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a dental floss used for cleaning between teeth and a method for producing the same.

  Between the teeth, plaque (plaque) is likely to stick, and it is a site that tends to cause tooth decay and periodontal disease. These plaques are made of water and organic substances, and most of the organic substances are bacteria (oral resident bacteria) and their metabolites. The bacteria change depending on the hygiene of the oral cavity, causing bad breath and periodontal disease. . Therefore, in order to remove the plaque and keep the oral cavity clean, correct tooth brushing has been conventionally encouraged. However, it is difficult for the toothbrush to reach the gap between the teeth, and the use of dental floss is effective in removing the plaque more effectively.

  As such dental floss, conventionally, a bundle of nylon fibers having a round cross section, a tape-like one using a polytetrafluoroethylene (PTFE) monofilament yarn, and the like are often used. However, the former has a problem that since the thread is thick, the feeling of use is bad, and it is difficult to insert between the teeth, and the plaque cannot be sufficiently wiped. The latter is easy to insert between the teeth, but the surface of the teeth between the teeth is not flat and there is a narrow groove, so if you insert the floss between the teeth, the floss will straighten. There is a problem that it is difficult to get into the groove and the plaque between the teeth cannot be sufficiently wiped off.

Therefore, the present applicant has developed and has already filed a dental floss having an excellent wiping effect between teeth, a soft contact with teeth and gums, and a good feeling of use (see Patent Documents 1 and 2).
JP2007-215702 JP2007-215703

  These dental flosses are highly evaluated for their excellent wiping effect and usability, but the interdental gap is extremely narrow due to crowding (random pile teeth) and deformation of the restoration after caries treatment. When cleaning is repeated while applying a constant tension to the floss, the ultrafine fiber multifilament, which is a thread material, repeatedly hits the unevenness of the tooth surface, so that a certain plaque wiping effect can be obtained, but the above ultrafine fiber It has been found that there is a possibility that the multifilament may become fuzzy or thread breakage and impair the feeling of use.

  The present invention has been made in view of such circumstances, and uses an ultrafine fiber multifilament, has an excellent wiping effect and a feeling of use, and does not cause fuzz or thread breakage and a method for producing the same. For the purpose of provision.

  In order to achieve the above-mentioned object, the present invention has a heat-bonded yarn as a main component around a core yarn composed of an ultrafine fiber multifilament having an average single yarn fineness of 1.1 dtex or less. The sheath yarn, which is thicker and has a higher thermal contraction rate than the core yarn, is spirally wound with a gap so that the winding number is 50 to 500 T / m. A dental floss partially fixed by fusion is a first gist, and among them, a floss having a cross-sectional shape of the ultrafine fiber multifilament is an atypical shape having an edge. And

  In addition, the present invention is, in particular, the ultrafine fiber multifilament obtained by dividing the split type composite fiber, and the segment in which the cross-sectional shape of the fiber after splitting is a radial shape is the same. The third aspect is a dental floss composed of a fan-shaped segment whose fiber cross-sectional shape complements the radial segment, and the sheath yarn is set to have a dry heat shrinkage higher by 5% or more than the core yarn. Dental floss is the fourth gist.

  Furthermore, the present invention provides a core yarn composed of ultra-fine fiber multifilaments having an average single yarn fineness of 1.1 dtex or less, the main component of which is a heat-sealing yarn, the average single yarn fineness being larger than that of the core yarn, and the core yarn. By winding the sheath thread having a higher thermal shrinkage rate in a spiral shape with a gap so that the winding number is 50 to 500 T / m, and by performing heat setting on the obtained filamentous body The fifth gist is a method for producing dental floss comprising the step of partially fixing the core yarn and the sheath yarn by thermal fusion.

  And especially this invention makes the 6th summary the manufacturing method of the dental floss whose said heat set is 200-230 degreeC dry heat processing especially.

  That is, the dental floss of the present invention uses a specific ultrafine fiber multifilament as a core yarn, a specific sheath yarn mainly composed of a heat fusion yarn is spirally wound around it, and both are bonded by heat fusion. It is intended to be partially fixed. According to this dental floss, the strength of the whole yarn is increased by the sheath yarn wound around the ultra-fine fiber multifilament used as the core yarn, and the teeth are carefully cleaned by applying a strong tension. Even when used under excessive interdental contact, no fuzz or thread breakage occurs.

  In addition, there is a difference in shrinkage between the core yarn and the sheath yarn, the sheath yarn is greatly contracted by heat setting, and the core yarn having a small contraction rate is kept in a relatively plump state, and the sheath yarn is helical. And the bulky core yarn jumps out from between the sheath yarn. For this reason, even if the floss is pinched, only the tension is applied to the sheath yarn, and the core yarn does not fully extend, and the shape of the core yarn protruding from between the sheath yarn is maintained. The interdental tooth, which was difficult to scrape by the special shape that combines a relatively hard helical sheath thread under tension and a relatively flexible and flexible core thread. The plaque in the surface groove can be efficiently scraped off. And since the ultrafine fiber multifilament, which is the core yarn, is moderately dispersed and has a gap, plaques scraped along the sheath yarn that is relatively tight can be taken into the gap of the ultrafine fiber multifilament sequentially. And reattachment to the teeth can be prevented. Even if the dental floss is tightened, the ultrafine fiber multifilament, which is the core yarn, has a degree of freedom, so that they do not fluff or break, and the yarn converges when passing between the teeth. Therefore, there is an advantage that it is easy to insert between teeth.

  Further, in the present invention, in particular, when the cross-sectional shape of the ultrafine fiber multifilament is an irregular shape having an edge, the effect of scraping plaque by the edge portion is high, which is preferable. Among them, the above-mentioned ultrafine fiber multifilament is obtained by dividing a split-type composite fiber, and a segment in which the cross-sectional shape of the fiber after the split is radial, and the cross-sectional shape of the fiber is also the above-mentioned radiation When the dental floss is composed of a segment that is a sector shape that complements the shape segment, the edges of the two types of segments are easily fitted to the unevenness of the teeth, and the plaque can be captured more reliably. Moreover, since the plaque scraped from the tooth surface is easily stored and held in the gaps between the radial segments, the plaque is less likely to reattach and the wiping effect is more excellent.

  Furthermore, in the present invention, in particular, when the sheath yarn is a dental floss set with a dry heat shrinkage of 5% or more higher than that of the core yarn, the twist of the yarn that appears after heat setting is particularly large and more excellent. A wiping effect can be obtained.

  And according to the manufacturing method of the dental floss of this invention, the said dental floss can be manufactured efficiently, without using a special apparatus.

  Moreover, in the said manufacturing method, when the said heat set is 200-230 degreeC dry heat processing, since the heat fusion by a sheath yarn and the expression of the thermal contraction of a core yarn and a sheath yarn are performed favorably, it is more excellent. High performance dental floss can be obtained.

  Next, the best embodiment of the dental floss of the present invention will be described in detail.

  For example, as shown in FIG. 1A (schematic enlarged view), the dental floss of the present invention is a sheath yarn Y whose main component is a heat-sealing yarn around a core yarn X composed of ultrafine fiber multifilaments. However, it is configured to be spirally wound with an appropriate gap. At least a part of the contact portion between the core yarn X and the sheath yarn Y is fixed by partial melting of the sheath yarn Y.

  The ultrafine fiber multifilament used for the core yarn X must have a single yarn fineness of 1.1 dtex or less. The above “single yarn fineness” refers to the fineness of each individual fiber constituting the multifilament, and, as will be described later, a composite fiber multifilament split as a very fine fiber multifilament (split yarn) When used, the segment fineness of each segment after splitting is shown.

  If the single yarn fineness exceeds 1.1 dtex and is thick, the unit fiber surface area of the dental floss becomes small, and unless the dental floss itself is thickened, it is difficult to obtain sufficient wiping properties, and a sufficient wiping effect is obtained. If it tries to obtain it, the dental floss itself will become thick, and it will be difficult to insert between the teeth. Moreover, once the plaque or food piece is scraped, it cannot be taken in between the fibers, and the plaque again adheres to the oral cavity such as teeth and gums.

  On the other hand, if the fine fiber has a single yarn fineness of 1.1 dtex or less, the plaque is scraped so as to be scraped off by a large number of thin fibers, and pushed up into the fiber group to be captured. The captured plaque is stored in a large amount in a large number of narrow spaces between the fibers to prevent reattachment, and a good scraping effect that cannot be obtained with a normal floss using a multifilament is obtained. Also, when inserting between teeth, because it is an aggregate of ultrafine fibers, it can freely change the cross-sectional shape and enter between narrow teeth, even if it has a certain bulkiness, It is very easy to insert floss between teeth.

  In the case of a conventional dental floss, in the case of a relatively bulky dental floss, in order to obtain easy insertion between teeth, a wax coating treatment or the like is usually performed. Even if it is bulky and thick, it can be smoothly inserted between teeth without a wax coating. Of course, a wax coating may be applied.

  Moreover, it is suitable for the effect that the single yarn fineness of the ultrafine fiber multifilament is within a range of 0.01 to 0.75 dtex. If it is less than 0.01 dtex, the strength of the core yarn X becomes weak, which is not preferable in production.

  And, the fiber cross-sectional shape of the ultrafine fiber multifilament of the present invention is not particularly limited, and among them, the irregular shape having an edge has a high plaque scraping effect by the ultrafine fiber multifilament, Is preferred.

  The “edge” refers to a projecting portion formed by a corner portion of the fiber having a curved cross section that is not a gentle arc shape but a bent corner shape. And although the angle of the said corner | angular part may be an obtuse angle, the sharper angle exhibits the wiping performance more excellent. However, in the outline of the fiber cross section, the two sides having the corners do not necessarily have to be straight lines, and may have an arc shape. The edge may be an obtuse angle, a right angle, or an acute angle, but is preferably a right angle or an acute angle, particularly an acute angle, from the viewpoint of efficiently obtaining a plaque scraping effect.

  Moreover, it is preferable that the said edge is exposed to the surface of dental floss, and it is preferable from the point of the wiping effect and a feeling of wiping that the edge is exposed to the surface of a thread | yarn at random.

  As an atypical fiber cross-sectional shape having an edge, for example, as shown in FIG. 2, a multifilament fiber cross-section composed of a radial segment A and a complementary segment B that complements the radial segment A is given. Can do. In these segments A and B, since many edges along the longitudinal direction of the fiber are formed (the part indicated by P in FIG. 2 and the part having the same shape is omitted), the plaque is scraped efficiently, Adhesion is also prevented and an excellent wiping effect can be obtained.

  In the case of such a radial segment A and a complementary segment B, the radial segment A is preferably obtained by dividing the complementary segment B into three or more. The upper limit is preferably about 16. Particularly preferably, it is divided into 4 to 8 pieces.

  As the unusual type ultrafine fiber multifilament having such an edge, a split type composite fiber is preferably split. For example, what consists of the radial segment A and the complementary segment B mentioned above can be obtained by splitting the split type composite fiber shown in FIG.

  Similarly, another example of the split type composite fiber that can obtain an extraordinary ultrafine fiber multifilament having an edge is one having a fiber cross section as shown in FIGS. 3B to 3H. be able to. In addition, the thing of FIG.3 (g) can obtain the ultrafine fiber multifilament which consists only of an inner component (D: It consists of 12 segments) by melt | dissolving and removing the outer part (C) in a composite fiber. it can. Moreover, the thing of FIG.3 (h) can obtain the ultrafine fiber multifilament which consists only of the fiber-forming component of D by melt | dissolving and removing the easily soluble component C. FIG.

  The splitting of the split type composite fiber can be performed by removing one component by dissolution or decomposition, swelling with a swelling agent, or shrinking with a shrinking agent. Further, it is possible to perform stress splitting in which a plurality of components are physically divided by friction or impact. In the present invention, stress splitting is preferred. More specifically, for example, splitting by hitting or stroking, splitting by washing with water, splitting by deflaming in the dyeing process, gear crimp, Examples thereof include a split fiber method by processing such as knit denit and false twist. Of these, split fiber by false twisting is preferable.

  When stress splitting is performed by false twisting, the degree of shape loss of each segment is low and it is easy to maintain the atypical degree of the fiber cross section, and the wiping effect of dental floss can be further enhanced. Moreover, in the false twisting, heat setting is performed in a state where twist is applied, and the twist is released, so that the filament can be crimped. As a result, the dental floss can be given volume and elasticity, so that the contact with the teeth and gums becomes soft, and insertion between narrow teeth becomes easy and the feeling of use is excellent. Furthermore, since it can be easily obtained without complicated processes, it is possible to reduce the use of extra drugs and the like.

  Examples of the polymer for forming the ultrafine fiber multifilament used as the core yarn X of the present invention include, for example, polyesters such as polyethylene terephthalate and polybutylene terephthalate, polyamides such as nylon 6 and nylon 66, and polypropylenes such as polypropylene and polyethylene. Examples thereof include olefins. In the case where stress splitting is performed using split-type composite fibers as described above, combinations of polymers such as polyester and polyamide, polypropylene and polyamide, polyethylene and polyamide are preferably used.

  In addition, as a particularly preferable combination in the case of using the split type composite fiber, a combination in which one is polyester and the other is polyamide. That is, when used as a dental floss, the polyamide having a large thermal shrinkage rate of the polymer greatly shrinks, and the polyester does not shrink so much, so a large gap is formed between each divided segment, and the gap is scraped off. Since plaque easily enters, the wiping effect is excellent. Further, splitting by stress is facilitated, the degree of deformation of the fiber cross-sectional shape is low, the shape of the edge portion of the segment is easily maintained, and dental floss having a high wiping effect can be obtained.

  In particular, when the radial segment (A in FIG. 2) is polyamide and the complementary segment (B in FIG. 2) is polyester, the polyamide portion is soft and the radial segment is soft against the teeth and gums. In addition, since the hard complementary polyester portion plays a role of scraping plaque, a polyester having a further excellent wiping effect and excellent wiping feeling and use feeling can be obtained.

  In addition, the ultrafine fiber multifilament used as the core yarn X of the present invention is processed to impart bulkiness from the point of softening the contact with teeth and gums and the ability to efficiently scrape plaque. Preferably it is done. Examples of such a processing method include twisting, heat setting, untwisting method, false twisting method, scraping method, indentation method, molding method, air injection method, and composite crimping method. In the present invention, it is preferable to perform false twisting by false twisting. And when the said split type composite fiber is used as the said ultra fine fiber multifilament, stress splitting can be performed at the time of the said false twist process.

  Furthermore, the ultrafine fiber multifilament used as the core yarn X of the present invention can be obtained by aligning a plurality of these to obtain a combined yarn. In general, it is preferable to simply twist the yarns when they are used as a plurality of multifilaments. Since the sheath yarn Y is wound around the core yarn X using the filament and heat-sealed, it is not necessary to twist. Of course, it can be used as a twisted yarn.

  Thus, in the core yarn X of the present invention, the above-mentioned ultrafine fiber multifilament is subjected to bulky processing such as false twisting, if necessary, and used alone or in combination. Moreover, when using two or more, you may twist this. And the external appearance and physical property of the dental floss obtained can be controlled by setting the conditions of the said false twist process, a combined yarn, and a combined twist suitably.

  By the way, when the core yarn X is an ultrafine fiber multifilament derived from a split type composite fiber composed of a polyamide radial segment and a polyester complementary segment, the false twist number is 2000 to 5000 T / M at about 150 to 185 ° C. When a plurality of false twisted yarns are used, the sheath yarn Y described later can be spirally wound to obtain a dental floss excellent in wiping effect. it can.

  Furthermore, the ultrafine fiber multifilament used for the core yarn X of the present invention preferably has a dry heat shrinkage of 10% or less. That is, the heat shrinkage rate of the core yarn X is kept low, and the sheath yarn Y is set to have a higher heat shrinkage rate than the core yarn X, as will be described later. This is because each fiber of the X ultrafine fiber multifilament can be separated, and the plaque uptake efficiency can be increased.

  In the present invention, the total fineness of the core yarn X is preferably 100 to 1100 dtex. Especially, it is more suitable that it is 200-900 dtex, and also it is 300-700 dtex. That is, if the total fineness of the core yarn X is too small, it becomes difficult to obtain the bulkiness unique to ultrafine fibers, and when the sheath yarn X is wound in a spiral shape and contracted, the whole is bent into a jagged shape. Because it is difficult to become, it is not preferable. Conversely, if the total fineness of the core yarn X is too large, the combination with the sheath yarn becomes thick and difficult to enter between the teeth, which is not preferable.

  On the other hand, the yarn used for the sheath yarn Y of the present invention must be mainly composed of a heat-sealing yarn. The “heat-sealing yarn” means that a heat-fusible component having a low melting point is exposed on at least a part of the fiber surface constituting the yarn, and is heated above the melting point, so It is a yarn having a function of fixing other fibers in contact with this portion by softening or melting the arrival component. And the above-mentioned “having the heat fusion yarn as a main component” means that the heat fusion yarn is used in an amount of 50% by weight or more. That is, when the heat-sealing yarn is less than 50% by weight, the core yarn X is not sufficiently fixed by the heat-sealing component, and fiber fluffing and yarn breakage are likely to occur.

  Note that the “fixing” does not mean that the heat fusion component is melted into a liquid and the partner is completely bonded and fixed like an adhesive. It is desirable to fix the limited portion and fix the other portions to the extent that the degree of freedom of both is maintained.

  Examples of the heat-sealing component include polyesters such as polybutylene terephthalate, polytrimethylene terephthalate, and polyethylene terephthalate, and copolymers thereof.

  Moreover, as a preferable copolyester as the heat fusion component, terephthalic acid and ethylene glycol are the main components, and as the copolymer component, acid components such as oxalic acid, malonic acid, azelaic acid, adipic acid, and sebacic acid are used. Aromatic dicarboxylic acids such as aliphatic dicarboxylic acid, phthalic acid, isophthalic acid, naphthalenedicarboxylic acid and / or alicyclic dicarboxylic acids such as hexahydroterephthalic acid and diethyl glycol, polyethylene glycol, propylene glycol, hexanediol, paraxylene glycol , One or a combination of two or more aliphatic, alicyclic or aromatic diol glycols such as bishydroxyethoxyphenylpropane, and a parahydroxybenzoic acid or the like as desired. 50 oxyacids % Copolymerized ester was added at a rate of less is preferred.

  As the heat-sealing yarn used as the sheath yarn Y of the present invention, a multifilament composed of synthetic fibers in which the entire fiber is composed of the heat-sealing component, a heat-sealing component, and a non-heat-sealing component ( And a multifilament made of a composite fiber composited with a component having a softening point higher by 30 ° C. or more than the heat fusion component. . However, the above-mentioned “softening point” refers to a temperature at which the resin constituting the synthetic fiber begins to soften. Specifically, according to the “softening temperature test method by thermomechanical analysis of thermoplastic film and sheet” of JIS K7196 method. The softening point to be measured.

  As the synthetic fiber in which the entire fiber is composed of a heat-sealing component, for example, a high shrinkage polyester fiber described in JP-A-2004-232159 is suitable. More specifically, a heat-shrinkable polyester fiber obtained by spinning polyethylene terephthalate obtained by copolymerizing isophthalic acid and 2,2-bis [4- (2-hydroxyethoxy) phenyl] propane by the SPD method. It is done.

  Further, it may be a copolyester multifilament obtained by copolymerizing the above-mentioned isophthalic acid and 2,2-bis [4- (2-hydroxyethoxy) phenyl] propane with a third component, and usually has a softening point of 200. A polyester multifilament (high shrinkage polyester multifilament) having a hot water shrinkage (BWS) of 10 to 40% is preferable. However, high-shrinkage polyester multifilaments may be easily deformed in the case of bobbin winding during transportation under harsh conditions at high temperatures such as in summer trucks. , A BWS of 20% or less is preferably used.

  On the other hand, as the composite fiber in which the heat fusion component and the non-heat fusion component are combined, it is preferable to use a core-sheath type composite filament in which the core portion is made of a non-heat fusion component and the sheath portion is made of a heat fusion component. It is. In addition to the complete core-sheath structure, various composite forms in which at least a part of the heat-sealing component is exposed on the surface can be mentioned. For example, composite fibers having a cross-sectional shape as shown in FIGS. In these drawings, the hatched portion indicates the portion formed with the heat-sealing component, and the white portion indicates the portion formed with the non-heat-sealing component. Also, the cross-sectional contour shape does not necessarily have to be circular, and various cross-sectional shapes such as an ellipse, a hollow, a triangle, a quadrangle, and a star can be used.

  Of these composite fibers, those having a heat fusion component exposed to 40% or more on the fiber surface are particularly suitable. And especially on the effect of fixing the core yarn X, as shown in FIG. 4A, a core-sheath type composite fiber in which a heat-seal component is disposed in the sheath and a non-heat-seal component is disposed in the core. Is preferably used.

  When such a core-sheath type composite fiber is used, a core-sheath type composite polyester multifilament using isophthalic acid copolymer polyester as the heat fusion component of the sheath and homopolyester as the non-heat fusion component of the core is optimal. is there. In this case, the core / sheath ratio is preferably set to 5/1 to 1/5 on a volume basis, and particularly preferably 3/1 to 1/2.

  In addition, the sheath yarn Y of the present invention can be used in combination with the above heat-sealed yarn and a non-heat-sealed yarn that does not contain a heat-sealing component in a proportion of less than 50% by weight of the sheath yarn Y. As such a non-heat-bonding yarn, various multifilaments made of a non-heat-bonding component such as the homopolyester are preferably used.

  Moreover, the sheath yarn Y of the present invention needs to have a higher heat shrinkage rate than the core yarn X. That is, by providing a difference in the thermal shrinkage rate between the sheath yarn and the core yarn, after heat setting, as shown in FIG. 1B, the yarn is regularly twisted and wound in a spiral shape. This is because, together with the unevenness of the outer peripheral surface by the sheath yarn, a high wiping effect that is not possible in the past can be obtained.

  More specifically, if the sheath yarn Y and the core yarn X have a difference in heat shrinkage rate, the sheath yarn is greatly shrunk by heat setting, and the core yarn X having a small shrinkage rate is maintained in a relatively plump state. Thus, the sheath yarn Y is spirally tightened, and the bulky core yarn X jumps out from between the sheath yarn Y and the sheath yarn X. For this reason, even if the floss is pinched, only the tension is applied to the sheath yarn Y, the core yarn X does not fully extend, and the core yarn X protrudes from between the sheath yarn Y and the sheath yarn Y. maintain. Due to the special shape in which this tension is applied and the relatively hard spiral sheath yarn Y and the relatively flexible and flexible core yarn X are combined, it has been difficult to scrape the teeth. The plaque in the groove of the tooth surface can be efficiently scraped. And since the ultrafine fiber multifilament that is the core yarn X is moderately dispersed and has a gap, the plaque scraped along the sheath yarn Y that is relatively tightly tightened is sequentially taken into the gap of the ultrafine fiber multifilament. And can prevent reattachment to the teeth. And even if the dental floss is taut, the ultrafine fiber multifilament that is the core yarn X has a degree of freedom, so that they do not fluff or break, and the yarn converges when passing between the teeth. It has the advantage of being easy to insert between teeth.

  And in order to fully express the effect derived from such a difference in heat shrinkage rate, it is possible to set the dry heat shrinkage rate of the sheath yarn Y to be 5% or more higher than the dry heat shrinkage rate of the core yarn X. Is preferable.

  The sheath yarn Y of the present invention needs to have a single yarn fineness larger than that of the core yarn X. That is, the core yarn X is wound around in a spiral shape so that the core yarn X is not loosened, and the plaque is scraped off like a razor with a certain strength. This is because higher rigidity than the core yarn X is required in the range.

  Incidentally, the single yarn fineness of the ultrafine fiber multifilament used as the core yarn X is preferably 1.1 dtex or less, more preferably 0.01 to 0.75 dtex as described above, but it is used as the sheath yarn Y. The single yarn fineness of the yarn mainly composed of the heat-sealed yarn is premised to be thicker than the core yarn X, and it is particularly preferably 1.5 times or more. And when the sheath yarn Y is a multifilament, it is suitable that the single yarn fineness is 1-6 dtex. That is, if the single yarn fineness of the sheath yarn Y is less than 1 dtex, the effect of scraping off the above-described plaque is weak, and conversely if it exceeds 6 dtex, the resulting dental floss becomes thick and it is difficult to enter between the teeth. Of course, the sheath yarn Y does not necessarily need to be a multifilament, and may be a monofilament. However, the multifilament is preferable in that it penetrates between teeth while crushing its cross section, and scrapes and takes in plaque. Is preferred.

  The total fineness of the sheath yarn Y is preferably 50 to 600 dtex, particularly 90 to 300 dtex for the same reason as described above.

  The dental floss of the present invention can be manufactured using the core yarn X and the sheath yarn Y, for example, as follows. That is, first, the core yarn X composed of the ultrafine fiber multifilament is prepared. Then, the sheath yarn Y is wound around the core yarn X while spirally winding it with a predetermined number of turns, and then heat-set at a predetermined temperature on the obtained filamentous body. And at least a part of the contact portion between the core yarn X and the sheath yarn Y is fixed by thermal fusion. In this way, the desired dental floss can be obtained.

  The dental floss of the present invention thus obtained is a specific ultrafine fiber multifilament as a core yarn X, and a specific sheath yarn Y having heat-fusibility is wound around it in a spiral shape. Both are partially fixed by heat fusion. Therefore, according to this dental floss, the strength of the whole yarn is increased by the sheath yarn Y wound around the ultrafine fiber multifilament that is the core yarn X, and the interdental teeth are carefully applied with strong tension. Can be cleaned.

  And since the gap | intervals have opened the thread | yarn wound by the said sheath yarn Y, the softness | flexibility of the core yarn X which consists of an ultrafine fiber multifilament is not impaired, and it has the outstanding usability | use_condition. In addition, since the sheath yarn Y and the core yarn X have a difference in thermal shrinkage due to the difference in thermal shrinkage between the sheath yarn Y and the core yarn X, the sheath yarn greatly contracts due to heat setting, and the shrinkage rate The core yarn X having a small diameter is tightened into the sheath yarn Y in a spiral manner while maintaining a relatively plump state, and the bulky core yarn X jumps out from between the sheath yarn Y and the sheath yarn X. It becomes a state. For this reason, even if the floss is pinched, only the tension is applied to the sheath yarn Y, the core yarn X does not extend completely, and the core yarn X protrudes from between the sheath yarn Y and the sheath yarn Y. maintain. It is difficult to scrape by the special shape in which the relatively hard spiral sheath yarn Y and the relatively soft and flexible core yarn X are combined. The plaque in the groove on the tooth surface can be efficiently scraped. And since the ultrafine fiber multifilament that is the core yarn X is moderately dispersed and has a gap, the plaque scraped along the sheath yarn Y that is relatively tightly tightened is sequentially taken into the gap of the ultrafine fiber multifilament. And can prevent reattachment to the teeth.

  The ultra-fine fiber multifilament of the core yarn X is partially fixed by the sheath yarn Y wound around the core yarn X, and even if the dental floss is pinched, the core yarn X is fixed to the sheath yarn Y. Since there is a degree of freedom between the two parts, they do not fluff or break, and even when they are passed between teeth, the yarn converges and is easily inserted between the teeth. Therefore, the dental floss of the present invention can be used comfortably to the end.

  In addition, in the said manufacturing method, it is necessary to set the winding number of the sheath yarn Y so that it may become 50-500 T / m. In other words, if it is less than 50 T / m, there is a possibility that the core yarn X will be bundled and fixed too much, and the core yarn X may become fluffed or broken, and conversely if it exceeds 500 T / m, the core exposed on the surface will be exposed. This is because the ratio of the yarn X is reduced, the plaque is not sufficiently taken up between the ultrafine fiber multifilaments, and the entire flexibility is impaired. Of these, the number of turns is particularly preferably 200 to 400 T / m in view of the effect.

  In the above production method, the heat setting conditions for fixing the core yarn X and the sheath yarn Y by heat fusion are appropriately set according to the type of yarn and the required characteristics. It is preferable to perform a dry heat treatment at ˜230 ° C. If the heat setting condition is too weak than the above range, the core yarn X and the sheath yarn Y may not be firmly fixed, and conversely if too strong, the fixing area increases and the rigidity of the entire yarn increases. This is because the feeling of use becomes worse.

  The thus obtained dental floss of the present invention preferably has a total fineness of 200 to 1300 dtex, more preferably 300 to 1000 dtex, and more preferably 400 to 900 dtex. . That is, if the total fineness is too small, the entire yarn volume may be lacking and the plaque scraping effect may be insufficient. Conversely, if the total fineness is too large, it will be difficult to enter between the teeth and the wiping effect will be reduced. This is because it may become insufficient.

  Furthermore, in the dental floss of the present invention, the area ratio between the core yarn X and the sheath yarn Y exposed on the surface of the floss is such that the area of the core yarn X: the area of the sheath yarn Y is 30:70 to 80:20. It is preferable to set so. That is, if the exposure rate of the core yarn X is too small, the effect of taking up plaque may be weakened. Conversely, if the exposure rate is too high, the effect of scraping the plaque by the sheath yarn Y may be weakened. Because.

  Next, examples of the present invention will be described together with comparative examples. However, the present invention is not limited to the following examples.

[Example 1]
167 dtex / 56 f split-type composite fiber multifilament having a cross-sectional shape shown in FIG. 2A (radial A component: polyamide, single yarn fineness 0.75 dtex, four complementary B components [fan shape]: single polyester Yarn fineness 0.56 dtex) (Berryma [registered trademark] manufactured by KB Seiren) was prepared. This filament is supplied at an overfeed rate of 2%, false twisted in the S direction under conditions of a spindle rotation speed of 400,000 rpm, a false twist number of 4700 T / M, and a set temperature of 175 ° C. Shrinkage rate 8.8%, 168 dtex / 280f) was obtained.

  Next, a core-sheathed polyester multifilament of 84 dtex / 24f (core: high-viscosity polyester, sheath: low-melting polyester, Using a yarn with two dry heat shrinkage rates of 17%) as the sheath yarn Y, a spiral is formed around the core yarn X with a gap so that the sheath yarn Y has a winding number of 300 T / m. Covering was performed by winding the wire around. And the target dental floss was obtained by winding the obtained filamentous body at a winding speed of 60 m / min (heating time to the thread of 1 second) while performing heat setting at a setting temperature of 210 ° C. A micrograph (magnification: x50) of the cross section of this dental floss is shown in FIG.

[Comparative Example 1]
A yarn similar to the core yarn X used in Example 1 and a yarn similar to the sheath yarn Y are aligned with each other, twisted by 200 T / m in the Z direction, and set at a temperature of 210 ° C. Then, heat setting was performed at a winding speed of 60 m / min to obtain a twisted yarn. This twisted yarn was used as dental floss.

[Comparative Example 2]
In Example 1, four yarns similar to the false twisted yarn used for the core yarn X were aligned, and a twisted yarn of 200 T / m was applied in the Z direction to obtain a twisted yarn. This twisted yarn was used as dental floss.

[Examples 2 to 4]
When covering with the sheath yarn Y, the number of turns was changed as shown in Table 2 below. Other than that was carried out similarly to Example 1, and obtained dental floss.

[Comparative Examples 3 and 4]
The temperature of the heat set after covering with the sheath yarn Y was changed as shown in Table 3 below. Other than that was carried out similarly to Example 1, and obtained dental floss.

Example 5
FIG. 2 (b) 110 dtex / 50 f split-type composite fiber multifilament (radial A component: polyamide, single yarn fineness 2 dtex, 8 complementary B components [fan shape]: polyester single yarn fineness 0.2 dtex) was prepared. This filament is supplied at an overfeed rate of 2%, false twisted in the S direction under conditions of a spindle rotation speed of 400,000 rpm, a false twist number of 4000 T / M, and a set temperature of 175 ° C. A shrinkage rate of 10%, 110 dtex / 450 f) was obtained.

  Next, a core-sheathed polyester multifilament of 84 dtex / 24f (core: high-viscosity polyester, sheath: low-melting polyester, Using a yarn with two dry heat shrinkage rates of 17%) as the sheath yarn Y, a spiral is formed around the core yarn X with a gap so that the sheath yarn Y has a winding number of 300 T / m. Covering was performed by winding the wire around. And the target dental floss was obtained by winding the obtained filamentous body at a winding speed of 60 m / min (heating time to the thread of 1 second) while performing heat setting at a setting temperature of 210 ° C.

Example 6
A 167 dtex / 50 f split-type composite fiber multifilament (C component: alkali-soluble polyester, D component: regular polyester, C, D area ratio of 1: 3) having a cross-sectional shape of FIG. Three of these filaments were drawn together, twisted in the S direction at 50 T / m, and twisted at 70 ° C. for 20 minutes to obtain a 501 dtex / 150 f twisted yarn. This twisted yarn is immersed in a 25% by weight aqueous sodium hydroxide solution to reduce the weight, and the alkali-soluble polyester is removed. The resulting yarn is used as the core yarn X (dry heat shrinkage 10%, 375 dtex / 1350f). It was. A dental floss was obtained in the same manner as in Example 1 except that this was used as the core yarn X.

  About these example products and comparative products, 5 professional monitors were used in the same way as normal dental floss, and their ease of insertion between teeth, wiping, and softness against teeth and gums. , ◎ ... very good, ◯ ... good, △ ... slightly poor, evaluated in three stages. These results are shown in Tables 1 to 4 below. In addition, the evaluation made the evaluation that three or more evaluations corresponded (hereinafter the same).

  In addition, artificial plaque (Nissin Co., Ltd.) was applied to the side of a cylindrical glass bottle, and both ends of the dental floss cut to 20 cm were stretched to the left and right, and in this state, the artificial plaque application surface was reciprocated once. It was. Then, the amount of artificial plaque remaining on the side surface of the glass bottle was visually observed, and evaluated in three stages: ◎… no residue, …… somewhat remained, but generally good, △… residual. These results are also shown in Tables 1 to 4 below.

  From the above results, it can be seen that the example products are generally excellent in any evaluation item. On the other hand, it can be seen that the comparative product has a large number of Δ in evaluation items and has practical problems.

(A) is explanatory drawing which shows a structure of the dental floss which is one embodiment of this invention, (b) is explanatory drawing of the characteristic. It is a typical cross section which shows an example of the ultrafine fiber multifilament used for the core yarn X of this invention. (A)-(h) is a cross-sectional view which shows all the other examples of the said ultrafine fiber multifilament. (A)-(l) is a cross-sectional view which shows the example of the heat sealing | fusion yarn used for the sheath yarn Y of this invention. It is an electron micrograph which shows the cross section of one Example of this invention.

Explanation of symbols

X core yarn Y sheath yarn

Claims (6)

  Around the core yarn consisting of ultrafine fiber multifilaments with an average single yarn fineness of 1.1 dtex or less, the main yarn is a heat-bonding yarn, the average single yarn fineness is thicker than the core yarn, and the thermal shrinkage is higher than the core yarn. The sheath yarn is spirally wound with a gap so that the winding number is 50 to 500 T / m, and the core yarn and the sheath yarn are partially fixed by thermal fusion. Characteristic dental floss.   The dental floss according to claim 1, wherein a fiber cross-sectional shape of the ultrafine fiber multifilament is a variant having an edge.   The ultrafine fiber multifilament is obtained by dividing a split-type composite fiber, and a segment in which the cross-sectional shape of the fiber after splitting is a radial shape, and a sector shape in which the cross-sectional shape of the fiber complements the radial segment. The dental floss of Claim 2 comprised by the segment which becomes.   The dental floss according to any one of claims 1 to 3, wherein the sheath yarn is set to have a dry heat shrinkage of 5% or more higher than that of the core yarn.   The method for producing dental floss according to claim 1, wherein a heat-sealed yarn is a main component around a core yarn composed of ultrafine fiber multifilaments having an average single yarn fineness of 1.1 dtex or less, and the average single yarn is formed from the core yarn. A step of winding a sheath yarn having a high fineness and a thermal contraction rate higher than that of the core yarn in a spiral manner with a gap of 50 to 500 T / m, and heat to the obtained filament A method for producing dental floss, comprising the step of partially fixing the core yarn and the sheath yarn by heat fusion by performing setting.   The method for producing dental floss according to claim 5, wherein the heat set is a dry heat treatment at 200 to 230 ° C.