KR101357446B1 - Heat-bondable composite fiber and process for producing the same - Google Patents

Abstract

An essential object of the invention is to provide a low-modulus, self-extensible thermal-adhesive bicomponent fiber comprising polyethylene terephthalate as the fiber-forming resin component thereof and capable of producing a nonwoven fabric or a fiber structure that has a high adhesive strength and is bulky and well drapable. The object of the invention is attained by a self-extensible thermal-adhesive bicomponent fiber that comprises a fiber-forming resin component and a thermal-adhesive resin component and is characterized in that the fiber-forming resin component comprises polyethylene terephthalate, that the thermal-adhesive resin component comprises a crystalline thermoplastic resin having a melting point lower by at least 20°C than that of the fiber-forming resin component, and that its breaking elongation is from 130 to 600 %, its 100 % elongation tensile strength is from 0.3 to 1.0 cN/dtex and its 120°C dry heat shrinkage is smaller than -1.0 %; and by a method for producing it.

Description

Heat-adhesive composite fiber and its manufacturing method {HEAT-BONDABLE COMPOSITE FIBER AND PROCESS FOR PRODUCING THE SAME}

The present invention relates to a self-expandable heat-adhesive composite fiber having a low modulus, having self-extension at the time of thermal bonding, and showing a soft texture when it is made as a heat-bonding nonwoven fabric, and a manufacturing method thereof.

Generally, the heat-adhesive composite fiber represented by the core-sheath type heat-adhesive composite fiber which makes a heat adhesive resin component the sheath and makes a fiber forming resin component the core is a card method. After forming the fibrous web by the airlaid method, the wet papermaking method, or the like, the heat-adhesive resin component is melted by a hot air dryer treatment or a hot roll treatment to form an interfiber bond and used as a nonwoven fabric. That is, since the adhesive agent which uses an organic solvent as a solvent is not used, the advantage that the discharge | emission of harmful substances, including an organic solvent, is small is mentioned as an advantage. Moreover, since the advantages of the improvement of the production speed and the accompanying cost reduction are also great, they have been widely used in fiber structures such as fiber cushions and bed mats, and nonwoven fabrics.

Among them, in the case of heat-adhesive nonwoven fabrics represented by hygienic materials such as paper diapers or sanitary napkins, the nonwoven fabric may be in direct contact with the skin. It is required to have bulkiness. And the nonwoven fabric which has such a characteristic is continuously examined from before.

One method for thermally bonding a web obtained from heat-adhesive fibers is a heat transfer method in which a part of the web is thermocompressed by softening or melting by embossing roll or the like to join. In this method, the nonwoven fabric tends to bend at the boundary between the thermocompression bonding region and the non-thermocompression bonding region, and the resulting nonwoven fabric is excellent in drape. However, since the fibers in the thermocompression-bonding region are flattened by pressing, the compressed portion is cured to lose the bulkiness of the nonwoven fabric, and the obtained nonwoven fabric has only a paper-like feel.

On the other hand, as another method of thermally bonding the web obtained from the heat-adhesive fiber, there is an air through method in which hot air is sprayed on the entire web to soften or melt the intersection points of the fibers. In this method, since the hot air is allowed to pass while leaving the volume of the web to some extent, the obtained nonwoven fabric has bulkiness, and the obtained nonwoven fabric does not have a partially cured area, and the surface touch is smooth. On the other hand, when the nonwoven fabric is bent, irregular outer cracks easily come out of the nonwoven fabric, resulting in a nonwoven fabric having poor drape.

As the solution means, Patent Literature 1 discloses the following method. In other words, by the high-speed spinning method, the orientation index of the heat-adhesive resin component is 25% or less, and the orientation index of the fiber-forming resin component is 40% or more, so that the adhesive point strength is strong, and it is fused at lower temperatures, and the thermal shrinkage rate is higher. Small thermally adhesive composite fibers have been obtained. By adhering the mixed web of the heat-adhesive composite fiber and the non-heat-adhesive fiber by an air through method, it is a technique for producing a nonwoven fabric having drape and bulkiness and sufficient nonwoven fabric strength. However, the high-speed spinning method does not say that the current short fiber manufacturing process is still sufficient in process stability, and the yield is poor. In addition, considering the performance of the obtained short fibers, the cost performance is not sufficient, and it can be said that there are still many problems in commercial production of the short fibers by the high-speed spinning method. Furthermore, in the case where the heat-adhesive nonwoven fabric is formed of the heat-adhesive composite fiber alone, the number of adhesive intersections in the nonwoven fabric increases, so that it is difficult to obtain a nonwoven fabric having a soft texture, and a non-woven fabric having poor drape property tends to be obtained. Thus, in general, nonwoven fabrics are manufactured by blending non-thermal adhesive fibers for the purpose of reducing the number of adhesive intersections. In this case, the nonwoven fabric strength tends to be lowered because the number of adhesive intersections in the nonwoven fabric is reduced. Therefore, nonwoven fabric strength and soft texture were not necessarily sufficient levels.

Moreover, the example which showed the heat-adhesive composite fiber whose fiber-forming resin component comprises a core component whose core component is polyethylene terephthalate (it describes as PET hereafter) is not disclosed by patent document 1 not. When the core component of the heat-adhesive composite fiber is made of PET, the melting point of the core component is sufficiently higher than the melting point of the super component, compared to the case where the core component of the heat-adhesive composite fiber is polypropylene (hereinafter referred to as PP). Since it can be done, the thermal bonding strength of the nonwoven fabric obtained can further be improved. Moreover, since the composite fiber which makes such a shim component PET is comparatively high rigidity, it has the potential to obtain a bulky nonwoven fabric. However, even if a nonwoven fabric is prepared using a low magnification stretching composite or a simple unstretched composite fiber described in Patent Document 1, thermal shrinkage is insufficient because the orientation crystallinity of the core component of the composite fiber used is insufficient. It became a big thing. In addition, when high-speed spinning as described in Patent Literature 1 is applied to a composite fiber having a shim component as PET, in order to prevent the shim component from rapidly solidifying, together with the melting temperature of the shim component of the composite fiber at the time of spinning, It is inevitable to raise the melting temperature of the supercomponent of the composite fiber. Then, since the deterioration of the polymer constituting the supercomponent and the spinning draft were large, there was a problem that single yarns were very likely to occur during spinning.

(Patent Document 1) Japanese Unexamined Patent Publication No. 2005-350836

DISCLOSURE OF INVENTION

Problems to be solved by the invention

The present invention has been made in the background of the prior art, and its object is to make a polyethylene terephthalate as a fiber-forming resin component, thereby making it possible to produce a nonwoven fabric or a fiber structure having high adhesion strength, bulkiness and good drape. It is to provide a low modulus self-extending heat-adhesive composite fiber.

Means for solving the problem

MEANS TO SOLVE THE PROBLEM As a result of earnestly examining in order to solve the said subject, the present inventors used crystalline thermoplastic resin which has melting | fusing point 20 degreeC lower than PET as a heat-adhesive resin component, and unstretched at the spinning speed of 1300 m / min or less. High stretching is achieved by cold stretching at 1.05 to 1.30 times while cooling the shrine in a non-heating or cooling medium, followed by relaxation heat shrinkage at a temperature of 10 ° C. or higher than both the glass transition point of the heat-adhesive resin component and the glass transition point of the fiber-forming resin component. The inventors have invented a low modulus self-expandable heat-adhesive composite fiber having PET as a fiber-forming resin component that satisfies strength, sufficient bulkiness and drape.

More specifically, the problem is a composite fiber composed of a fiber-forming resin component and a heat-adhesive resin component, wherein the fiber-forming resin component is made of polyethylene terephthalate (PET), and the heat-adhesive resin component is fiber-forming. It is composed of a crystalline thermoplastic resin having a melting point of 20 ° C. or lower than the resin component, and has an elongation at break of 130 to 600%, a 100% elongation stress of 0.3 to 1.0 cN / dtex, and a 120 ° C. dry heat shrinkage of -1.0%. The invention can be solved by the invention of a self-extending heat-adhesive composite fiber which is smaller. In addition, the above-mentioned problem is 10 times less than both the glass transition point of the heat-adhesive resin component and the glass transition point of the fiber-forming resin component after cold stretching the undrawn yarn of the composite fiber taken at a spinning speed of 1300 m / min or less by 1.05 to 1.30 times. The invention can be solved by the invention of a method for producing a heat-adhesive composite fiber, which is thermally relaxed at a temperature higher than 0 ° C.

Effects of the Invention

The nonwoven fabric produced by using the low modulus self-extending heat-adhesive composite fiber of the present invention can be applied to the heat-adhesive composite fiber itself without the need to reduce the adhesion point by blending the non-heat-adhesive fiber. Flexible texture based on low modulus properties and magnetic extensibility. At the same time, the nonwoven fabric can maintain high adhesive strength peculiar to the heat-bonded nonwoven fabric composed of the heat-adhesive composite fiber alone.

BEST MODE FOR CARRYING OUT THE INVENTION

EMBODIMENT OF THE INVENTION Hereinafter, embodiment of this invention is described in detail. First, the present invention is a composite fiber composed of a fiber-forming resin component and a heat-adhesive resin component. In more detail, the low modulus self-extension heat-adhesive composite fiber which makes the fiber forming resin component PET, and uses the crystalline thermoplastic resin which has a melting point 20 degreeC or more lower than PET as the heat adhesive resin component to be. If the melting point difference between the PET and the heat-adhesive resin component is less than 20 ° C, the fiber-forming resin component is also dissolved in the process of melting and adhering the heat-adhesive resin component, and thus it is not preferable to produce a nonwoven fabric or a fiber structure having high adhesive strength. not. As for the range of melting | fusing point difference, 20-180 degreeC is a preferable range.

This composite fiber is obtained by drawing a non-drawn yarn at a spinning speed of 100 to 1300 m / min using a known melting method of a composite fiber or by detention, then cold drawn to 1.05 to 1.30 times, and further, a glass transition point of PET ( 10 degrees C or more higher than both Tg of the thermoplastic crystalline resin which comprises Tg) and the thermosetting resin component, and 10 degrees C or less below melting | fusing point of a heat adhesive resin component, Preferably they are more than those Tg. 20 degreeC or more high and it can obtain by carrying out a relaxation heat shrink process at the temperature lower than 20 degreeC below the melting | fusing point of a heat-adhesive resin component. Specifically, the temperature higher than both the Tg of PET and the Tg of the thermoplastic crystalline resin which is the heat-adhesive resin component is, in most cases, the temperature higher than the Tg (about 70 ° C.) of PET. Therefore, it is preferable to perform the relaxation heat shrink treatment at a temperature of 80 ° C or higher, preferably 90 ° C or higher. More preferable temperature is 100 degreeC or more. The temperature at the time of this relaxation heat shrink processing can be performed in hot air or hot water. In this invention, since melting | fusing point of the crystalline thermoplastic resin which comprises a heat-adhesive resin component is 20 degreeC or more lower than melting | fusing point of PET as mentioned above, Tg of the thermoplastic crystalline resin which comprises a heat-adhesive resin component is This is because it is often lower than the Tg of PET. If the temperature of the relaxation heat shrink treatment is lower than this temperature range, it is not preferable because the shrinkage ratio at the time of thermal bonding of the composite fiber becomes large. If the temperature of the relaxation heat shrink treatment is too much higher than this temperature range, there is a possibility that the resin of the heat-adhesive resin component softens and similarly deadlocks. The relaxation heat shrink treatment may be a method of overfeeding the tow after stretching by 0.5 to 0.85 times so that tension is not applied in the hot water even when the tow is passed in the hot air without any tension applied thereto.

By the above-mentioned relaxation thermal contraction treatment, the low-stretched fibers shrink in the fiber axis direction due to residual strain, thereby forming crystals having a crystal axis inclined in a random direction from the fiber axis direction. In addition, by applying the temperature to the fiber, the crystal size of the crystal increases, and the crystal size increases even when the crystals in contact with each other are brought into contact with each other. For this reason, a phenomenon in which the fibers appear to be stretched occurs. This phenomenon is called self-extension, and the composite fiber of this invention shows.

This phenomenon is a phenomenon which becomes more remarkable in high speed spinning with a spinning speed of 2000 m / min or more. According to the inventor's examination, in the case of the non-drawn yarn obtained at a spinning speed of 1300 m / min or less, it was found that stretching was performed at a slight magnification and then relaxed thermal contraction was found to increase the magnetic elongation rate. The present invention has been reached. For example, in the case where the core component is drawn with PET (inherent viscosity: IV = 0.64 dL / g) and the super-component high-density polyethylene (MFR = 20 g / 10 min) at a spinning speed of 1150 m / min, the draw ratio If it exceeds 1.00 times, the magnetic elongation will increase, and the magnetic elongation will be maximum at the draw ratio of 1.20 times. In order to express the self-extension of the fiber, it is thought that the point is how to arrange the crystal direction randomly with respect to the fiber axis before crystallization, so that the fiber may be greatly shrunk before crystallization. Therefore, in the stretching process of the fiber, when cold stretching is performed at a stretching temperature lower than the stretching temperature at the time of the heating stretching operation using hot water, steam, or plate heater, the orientation crystallization by stretching is performed. While suppressing, the residual strain of an amorphous part can be enlarged and it is preferable to obtain the composite fiber of this invention. Here, "cold drawing" includes not only extending | stretching at room temperature but also extending | stretching in the atmosphere actively cooled to the temperature below room temperature. Specifically, the method of extending | stretching in the non-heated state at room temperature or the coolant cooled below room temperature is mentioned. More specifically, the method of extending | stretching in cold drawing in air, a cold water bath, etc. are mentioned preferably. As the refrigerant, as described above, in addition to air and water, gases such as rare gas, nitrogen, carbon dioxide and the like which are inert to the fiber-forming resin component and the heat-adhesive resin component forming the composite fiber of the present invention and are not swelled or dissolved. Or liquids, such as various oils which do not have solubility with respect to PET and a heat-adhesive resin component, can be selected suitably. The temperature of the refrigerant at the time of cold stretching is 0 to 30 ° C, preferably 10 to 25 ° C.

Therefore, the self-elongation rate at 120 ° C. of the composite fiber is greater than 1.0%, that is, the dry heat shrinkage at 120 ° C. of the composite fiber is less than -1.0%, and the tensile strength at 100% elongation of the composite fiber is 0.3 to 1.0. In order to set it as cN / dtex, it is necessary for the draw ratio to exist in the range of 1.05-1.30 times. When the draw ratio is less than 1.05 times, the tensile strength at 100% elongation is 1.0 cN / dtex or less, but the magnetic elongation is less than 1.0%, and the object of the present invention cannot be achieved. If the draw ratio exceeds 1.30 times, the tensile strength at 100% elongation exceeds 1.0 cN / dtex. And in the heat-adhesive nonwoven fabric which consists of a web of 100% of such heat-adhesive composite fibers, the nonwoven fabric which has the favorable drape property which is the objective of this invention cannot be obtained. When performing the said extending | stretching operation, extending | stretching temperature is so good that it is low, and when cold water is used as a refrigerant | coolant, it is especially preferable to set it as 0 degreeC or more and 25 degrees C or less. Performing the stretching operation at such a low temperature contributes to increasing the heat shrinkage rate of the obtained composite fiber because the crystallization accompanying the orientation and the heat generation can be suppressed by sequencing the heat generated from the composite fiber at the time of stretching. . As mentioned above, in the composite fiber of this invention, it is necessary to make 100% elongation stress 0.3-1.0 cN / dtex. If the 100% elongation stress is less than 0.3 cN / dtex, the nonwoven fabric strength is insufficient and the quality of the nonwoven fabric tends to be worse.

When manufacturing the composite fiber of this invention, a spinning speed needs to be 1300 m / min or less, Preferably it is 1200 m / min or less, More preferably, it is 100-1100 m / min. When the spinning speed exceeds 1300 m / min, the orientation of the undrawn yarn is improved, but the effect of expressing a high magnetic elongation rate by the low magnification stretching operation, which is a characteristic of the composite fiber of the present invention, is lessened.

The form of the self-expandable heat-adhesive composite fiber of the low modulus of the present invention is a core component of the fiber-forming resin component even if the fiber-forming resin component and the heat-adhesive resin component are composite fibers bonded in a so-called side-by-side type. It may be any of the sheath type | mold composite fiber which uses a heat-adhesive resin component as a super component. However, since the heat-adhesive resin component can be arranged in all directions perpendicular to the fiber axial direction, it is a core sheath composite fiber having the fiber-forming resin component as the core component and the heat-adhesive resin component as the supercomponent. desirable. In addition, concentric heart type composite fibers include concentric heart type composite fibers or eccentric core type composite fibers.

The heat adhesive resin component needs to select a crystalline thermoplastic resin. In the case of the amorphous thermoplastic resin, the molecular chains oriented at the time of spinning are greatly contracted due to melting and unoriented orientation. Preferred examples of the crystalline thermoplastic resins include polyolefin resins, crystalline copolyesters, and the like.

As an example of this polyolefin resin, crystalline polyolefin resin, such as crystalline polypropylene, a high density polyethylene, a medium density polyethylene, a low density polyethylene, or linear low density polyethylene, is mentioned. In addition, the crystalline thermoplastic resin constituting the heat-adhesive resin component is ethylene, propylene, butene-1, pentene-1 or acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid, crotonic acid, isocrotonic acid, mesaconic acid, Copolymerized polyolefin copolymerized with at least 1 type or more of the unsaturated compound which consists of a citraconic acid, a high acid, these ester, or these acid anhydride may be sufficient.

Moreover, the following polyester is mentioned preferably as an example of the crystalline copolyester used as a heat-adhesive resin component. That is, the aromatic dicarboxylic acid having an unsubstituted or sulfonic acid group such as isophthalic acid, naphthalene-2,6-dicarboxylic acid, sodium 5-sulfoisophthalate, or 5-sulfoisophthalate in the alkylene terephthalate. Aliphatic dicarboxylic acids such as adipic acid or sebacic acid, alicyclic dicarboxylic acids such as 1,4-cyclohexamethylenedicarboxylic acid, ω-hydroxyalkylcarboxylic acid, polyethylene glycol or polytetra The polyester copolymerized so that aliphatic diols, such as methylene glycol, or alicyclic diols, such as cyclohexamethylene-1, 4- dimethanol, may be shown may show the melting | fusing point aimed at. The alkylene terephthalate has a main dicarboxylic acid component as terephthalic acid or an ester forming derivative thereof, and the main diol component as ethylene glycol, diethylene glycol, trimethylene glycol, tetramethylene glycol, hexamethylene glycol or derivatives thereof. The polyester obtained using the combination of 1-3 types as a raw material is mentioned. Examples of the ester-forming derivative include lower dialkyl esters having 1 to 6 carbon atoms and lower diaryl esters having 6 to 10 carbon atoms. Preferred ester-forming derivatives are dimethyl esters or diphenyl esters. The copolymerization rate of these components is preferably adjusted in various ways by the copolymerization component so as to exhibit the desired melting point, preferably 5 to 50 mol%. In the heat-adhesive resin component of the present invention, when the fiber-forming resin component is PET, a form in which two or more kinds of crystalline thermoplastic resins having a melting point of 20 ° C or more lower than PET may be polymer blended may be used. Or a crystalline thermoplastic resin having a melting point difference of less than 20 ° C. between the amorphous thermoplastic resin and the PET may be contained within a range that does not significantly impair low heat shrinkability.

The elongation at break of the low modulus self-expandable heat-adhesive composite fiber of the present invention needs to be in the range of 130 to 600%, and preferably in the range of 170 to 450%. If the elongation at break of the composite fiber of this invention is less than 130%, since the orientation of a heat-adhesive resin component is high, adhesiveness will fall and nonwoven fabric strength will fall. In addition, when the elongation at break of the composite fiber of the present invention exceeds 600%, the strength of the composite fiber is substantially too small, and the strength of the heat-bonded nonwoven fabric cannot be increased.

The method of controlling the breaking elongation of the composite fiber within the range of 130 to 600% depends on the type of polymer to be combined and the melt viscosity, and a method of appropriately selecting the hole diameter and spinning speed of the nozzle for discharging the polymer. have. Among these, the effect which mainly selects a spinning speed suitably is large. In addition, in order to control elongation at break in the said range in this invention, although it changes also with a kind and combination of polymers, it is preferable to make a spinning speed into the range of 100-1300 m / min, and when elongation speed is made large, elongation at break is made small. As a result, the elongation at break can be increased by reducing the spinning speed.

The 120 ° C. dry heat shrinkage of the low modulus self-extending heat-adhesive composite fiber of the present invention has a characteristic of less than -1.0%. Although the minimum of dry heat shrinkage rate is not specifically limited, About -20.0% is estimated as a minimum. In the case of manufacturing the heat-bonded nonwoven fabric, the composite fiber is self-extended before heat bonding, so that the thickness in the thickness direction is not only increased, but also the low modulus fibers are oriented in the thickness direction in the nonwoven fabric. In consideration of this, a soft texture is obtained, and a feeling of pressure in the vertical direction to the skin, such as when used as a surface material of hygiene material, is reduced, and the drape is also good.

In the heat-adhesive composite fiber of the present invention, the fiber cross section of the composite fiber is preferably a concentric eccentric section or an eccentric eccentric section. In the case of a composite fiber having a side-by-side fiber cross section, when the web is formed, the three-dimensional crimp is expressed to increase the shrinkage of the web. In addition, the adhesive strength of the web is also reduced, so that the effect aimed at by the present invention can be slightly reduced. In addition, the fiber cross section of a composite fiber may be a solid fiber or a hollow fiber, and is not limited to a ring cross section, It is an elliptical cross section, a multileaf cross section, such as a 3-8 leaf cross section, 3 ~ Release cross-sections, such as polygonal cross sections, such as an octagon, may be sufficient. Here, a multi-lobed cross section shows the cross-sectional shape which has several convex part as if a leaf grew in the outer peripheral direction from a center part.

In the heat-adhesive composite fiber of the present invention, the fineness of the composite fiber may be selected according to the purpose, and is not particularly limited, but is generally used in the range of about 0.01 to 500 decitex. The fineness range can be achieved by, for example, setting the diameter of the spinneret through which the resin is discharged during spinning to a predetermined range.

Although the compound ratio of a fiber forming resin component and a heat-adhesive resin component is not specifically limited, It selects according to the request | requirement of the intensity | strength, volume, or thermal contraction rate of the target nonwoven fabric or fiber structure. It is preferable that ratio of a fiber forming resin component and a heat-adhesive resin component is about 10/90-90/10 by weight ratio.

The form of a fiber can take any form according to a use purpose, such as a multifilament, a monofilament, a staple fiber, a weave, and a tow. In the case of using the heat-adhesive composite fiber of the present invention as a staple fiber requiring a card process, it is preferable to impart a crimp in an appropriate range in order to impart good card passability to the heat-adhesive composite fiber. . The heat-adhesive composite fiber of the present invention has a remarkable drape property improvement effect, particularly in nonwoven fabrics having random fiber structures. Therefore, the self-expandable heat-adhesive composite fiber of this invention can manufacture the nonwoven fabric which consists of it by itself. As needed, you may mix with another fiber and manufacture a nonwoven fabric. As a method of obtaining a nonwoven fabric, a cantilever value is 10 cm by forming a web on a web by a card method, an air ray method, a wet evaporation method, or the like, by applying a predetermined heat in a hot air dryer or an emboss roll, or by thermally bonding the fibers to each other. The flexible heat-adhesive nonwoven fabric excellent in the following drape property can be obtained.

Hereinafter, although an Example demonstrates this invention further more concretely, this invention is not limited at all by this. Each item in the examples was measured by the following method.

(1) intrinsic viscosity (IV)

The intrinsic viscosity of the polyester was measured at a constant amount of the polymer, dissolved in o-chlorophenol at a concentration of 0.012 g / ml, and then determined at 35 ° C. according to a conventional method.

(2) Melt Flow Rate (MFR)

Melt flow rate was measured based on Japanese Industrial Standard K-7210 condition 4 (measurement temperature 190 degreeC, load 21.18N). In addition, a melt flow rate is the value measured using the polymer pellet before melt spinning as a sample.

(3) melting point (Tm), glass transition point (Tg)

Melting | fusing point and glass transition point of a polymer were measured at the temperature increase rate of 20 degree-C / min using the TA Thermal Analyst 2200 by TA Instruments Japan.

(4) Fineness

The fineness of the composite fiber was measured by the method described in Japanese Industrial Standard L-1015: 2005 8.5.1A.

(5) strength, elongation, 100% elongation stress

The strength, elongation, and 100% elongation stress of the composite fiber were measured by the method described in Japanese Industrial Standard L-1015: 2005 8.7.1. Since the composite fiber of this invention is easy to produce a difference in strength, elongation, and 100% elongation stress by the efficiency of a normal heat treatment, it measures the strength, elongation, and 100% elongation stress in single yarn. In this case, it is necessary to increase the measurement score. Since the measurement score is preferably 50 or more, the measurement score is set to 50 here, and each value is defined as the average value. In addition, 100% elongation stress could be measured because the stress at the 100% elongation of the load-strain curve at the time of the strength and elongation measurement was read.

(6) crimp number, crimp rate

The crimp number and crimp rate of the composite fiber were measured by the method described in Japanese Industrial Standard L-1015: 2005 8.12.1 to 8.12.2 method.

(7) 120 ° C Dry heat shrinkage

120 degreeC dry heat shrinkage rate of a composite fiber was implemented at 120 degreeC in Japanese Industrial Standards L-1015: 2005.8.15b).

(8) web area shrinkage

The composite fiber web area shrinkage was measured by the following method. A card web having an apparent weight of 30 g / m 2 made of 100% of a heat-adhesive composite short fiber cut to a fiber length of 51 mm was produced, and the web was cut into 25 cm squares. Next, the cut web was left to stand for 2 minutes in a hot air dryer (Satake Chemical Machinery Co., Ltd. hot air circulation constant temperature dryer: 41-S4) maintained at 150 ° C for heat treatment, and thermal bonding of the composite fibers was performed. The area A ₁ was calculated by measuring and multiplying the longitudinal and horizontal dimensions of the web after thermal bonding, and the area shrinkage was determined by the following equation.

Area Shrinkage (%) = ((A ₀ -A ₁ ) / A ₀ ] × 100

In the above formula, A ₀ = 5 cm × 5 cm = 625 (cm 2)

(9) nonwoven strong (adhesive strong)

From the web (thickness 5mm) after the heat bonding obtained by the above-mentioned method, the test piece of width 5cm and length 20cm is cut out in a machine direction (the direction which the fiber or web of a nonwoven fabric manufacturing process flows), and clamping interval 10cm , Tensile strength was measured at an elongation rate of 20 cm / min. The adhesive strength was taken as the value obtained by dividing the tensile strength at break by the test piece weight.

(10) ductility (cantilever value)

From the web (thickness 5mm) after the heat bonding obtained by the method mentioned above, the test piece of width 2.5cm and length 25cm was cut out in the machine direction, and it measured by the method of Japanese Industrial Standard L-1086: 1983 6.12.1. . The cantilever value only in the machine direction was shown.

The specific measuring method of a cantilever value is as follows. That is, the test piece cut out along the board | substrate was put on the horizontal surface where the surface which has one side 45 degree slope is smooth. Next, one end of the test piece is exactly aligned with the one end of the horizontal side of the horizontal bar (joint part of the slope of 45 degrees and the horizontal bar), and the position of the other end of the test piece is measured as the length from the one end of the slope side of the 45 degree. Since the length of the test piece is 25 cm, this value is 25 cm. Next, the test piece is slid gently in the slope direction by a suitable method, and when the center point of one end of the test piece reaches the same plane as the slope, the position of the other end is measured as the length from the one end of the slope side of 45 degrees. This value is referred to as measured value A. The difference between 25 cm and this measured value A is the cantilever value. The front and back of five test pieces were measured, respectively, and the average value was made into the cantilever value of the test piece. The larger the cantilever value, the harder the test piece is, and the poorer the drape property of the test piece is. The smaller the cantilever value, the softer the test piece is, and the better the drape property of the test piece.

Example 1

Polyethylene terephthalate (PET) of IV = 0.64 dL / g, Tg = 70 ° C, Tm = 256 ° C for the core component (fibrous resin component), and MFR = 20g / 10min for the supercomponent (thermal adhesive resin component) , Tm = 131 ° C (Tg is less than 0 degrees) was used high density polyethylene (HDPE). After melting these resins to 290 ° C and 250 ° C, the composite fiber is formed such that the core component weight ratio and the ultracomponent weight ratio are 50 wt%: 50 wt% by weight using a well-known mold for the core sheath composite fiber. And the unstretched yarn was obtained by spinning on the conditions of discharge amount 0.70g / min / hole and the spinning speed of 1150m / min. After cold stretching the unstretched yarn 1.20 times, the yarn after cold stretching was immersed in an aqueous solution of lauryl phosphate potassium salt and polyoxyethylene-modified silicone composed of 80 wt%: 20 wt% of cold emulsion, and a stuffing box was installed. A machine crimp of 11 pieces / 25 mm was provided using a pressurized crimper. And the yarn which gave the crimp was subjected to relaxation heat shrink processing and drying process by 110 degreeC hot air which is 40 degreeC higher than the glass transition point of a core component, and cut | disconnected to 51 mm of fiber lengths under tension. The single yarn fineness of the obtained heat-adhesive composite fiber was 6.4 dtex, strength 0.76 cN / dtex, elongation 442%, 100% elongation stress 0.37 cN / dtex, and 120 degreeC dry heat shrinkage -2.6%. The web area shrinkage of the web made of 100% of the heat-adhesive composite fiber was -7.5%, the nonwoven fabric strength was 15.1 kg / g, and the cantilever value was 8.50 cm.

Comparative Example 1

The composite fiber was manufactured on the same conditions as Example 1 except the unstretched yarn obtained in Example 1 was extended | stretched 2.5 times in 70 degreeC warm water, and then extended | stretched 1.2 times in 90 degreeC warm water. Single yarn fineness of the obtained heat-adhesive composite fiber was 2.6 dtex, strength 2.49 cN / dtex, elongation 37.1%, and 120 degreeC dry heat shrinkage rate 2.5%. Since the elongation of the heat-adhesive composite fiber was less than 100%, 100% elongation stress could not be measured. The web area shrinkage of the web made of 100% of the heat-adhesive composite fiber was 5%, the nonwoven fabric strength was 20.5 kg / g, and the cantilever value was 12.90 cm.

Comparative Example 2

A composite fiber was produced under the same conditions as in Example 1 except that the stretching treatment was not performed. The single yarn fineness of the obtained heat-adhesive composite fiber was 6.47 dtex, strength 0.60 cN / dtex, elongation 460.3%, 100% elongation stress 0.37 cN / dtex, and 120 degreeC dry heat shrinkage -0.7%. The web area shrinkage of the web made of 100% of the heat-adhesive composite fiber was -1.45%, the nonwoven fabric strength was 14.5 kg / g, and the cantilever value was 7.90 cm.

Example 2

A composite fiber was produced under the same conditions as in Example 1 except that the draw ratio of the cold drawing was increased to 1.1 times. The single yarn fineness of the obtained heat-adhesive composite fiber was 6.41 dtex, strength 0.65 cN / dtex, elongation 424.1%, 100% elongation stress 0.41 cN / dtex, and 120 degreeC dry heat shrinkage -1.9%. The web area shrinkage of the web made of 100% of the heat-adhesive composite fiber was -5.6%, the nonwoven fabric strength was 16.5 kg / g, and the cantilever value was 8.10 cm.

Example 3

A composite fiber was produced under the same conditions as in Example 1 except that the draw ratio was 1.30 times that of cold drawing. The single yarn fineness of the obtained heat-adhesive composite fiber was 6.22 dtex, strength 0.72 cN / dtex, elongation 381.8%, 100% elongation stress 0.46 cN / dtex, and 120 degreeC dry heat shrinkage -2.0%. The web area shrinkage of the web made of 100% of the heat-adhesive composite fiber was -6.1%, the nonwoven fabric strength was 17.1 kg / g, and the cantilever value was 8.90 cm.

Comparative Example 3

A composite fiber was produced under the same conditions as in Example 1 except that the draw ratio was 1.4 times the draw ratio. Single yarn fineness of the obtained heat-adhesive composite fiber was 6.14 dtex, strength 0.75 cN / dtex, elongation 346.8%, 100% elongation stress 0.53 cN / dtex, and 120 degreeC dry heat shrinkage -0.6%. The web area shrinkage of the web made of 100% of the heat-adhesive composite fiber was -1.8%, the nonwoven fabric strength was 18.4 kg / g, and the cantilever value was 10.1 cm.

Example 4

A composite fiber was produced under the same conditions as in Example 1 except that cold stretching was carried out while cooling in a water bath controlled at a water temperature of 20 ° C. Single yarn fineness of the obtained heat-adhesive composite fiber was 6.52 dtex, strength 0.65 cN / dtex, elongation 459.3%, 100% elongation stress 0.39 cN / dtex, and 120 degreeC dry heat shrinkage -3.2%. The web area shrinkage of the web made of 100% of the heat-adhesive composite fiber was -9.5%, the nonwoven fabric strength was 15.3 kg / g, and the cantilever value was 8.13 cm.

Example 5

The loosening heat shrinkage treatment and heat treatment were performed by adding 0.7 times of overfeed in a 95 degreeC warm water bath, and the composite fiber was manufactured on the same conditions as Example 1 except not performing hot air drying after that. The single yarn fineness of the obtained heat-adhesive composite fiber was 6.58 dtex, strength 0.68 cN / dtex, elongation 443.3%, 100% elongation stress 0.41 cN / dtex, and 120 degreeC dry heat shrinkage -3.9%. The web area shrinkage of the web made of 100% of the heat-adhesive composite fiber was -11.4%, the nonwoven fabric strength was 14.9 kg / g, and the cantilever value was 8.90 cm.

Example 6

Polyethylene terephthalate (PET) of IV = 0.64 dL / g, Tg = 70 ° C, Tm = 256 ° C for the core component (fibrous resin component), and MFR = 40g / 10min for the supercomponent (thermal adhesive resin component) After melting the crystalline copolyester of Tm = 152 ℃, Tg = 43 ℃ (polyethylene terephthalate copolymerized 20 mol% isophthalic acid, 50 mol% tetramethylene glycol) to 290 ℃, 255 ℃, respectively The composite fiber is formed by using a well-known cardiac type composite fiber mold such that the core component weight ratio and the ultracomponent weight ratio are 50 wt%: 50 wt%, and the discharge amount is 0.71 g / min / hole, and the spinning speed is 1250 m / min. After the undrawn yarn was cold drawn 1.2 times, the yarn after cold stretching was immersed in an aqueous solution of an emulsion consisting of 80 wt%: 20 wt% of lauryl phosphate potassium salt and polyoxyethylene-modified silicone. Stuffing box A machine crimp of 11 pieces / 25 mm was applied using the formed press-type crimper, and the yarns to which the crimps were applied were subjected to drying and relaxation heat treatment in a hot air at 90 ° C. under tension, and cut into 51 mm of fiber length. The single yarn fineness of the obtained heat-adhesive composite fiber was 5.7 dtex, strength 0.94 cN / dtex, elongation 392%, 100% elongation stress 0.35 cN / dtex, and 120 ° C. dry heat shrinkage ratio -3.8%. The web area shrinkage ratio of the web made of% (but the heat bonding temperature was changed to 180 ° C.) was -11.2%, the nonwoven fabric strength was 12.3 kg / g, and the cantilever value was 8.30 cm.

The low modulus self-extending heat-adhesive composite fiber of the present invention uses PET as a fiber-forming resin component, and also has a small discharge during manufacture, so that the single yarn during spinning is significantly less. In addition, when the nonwoven fabric is manufactured using the composite fiber, a bulky nonwoven fabric having high adhesiveness, high drape property and good texture can be obtained.

Claims (8)

A composite fiber composed of a fiber-forming resin component and a heat-adhesive resin component, wherein the fiber-forming resin component is made of polyethylene terephthalate, and the heat-adhesive resin component has a melting point of at least 20 ° C lower than that of the fiber-forming resin component. A self-expandable heat-adhesive composite fiber, comprising a thermoplastic resin, having an elongation at break of 130 to 600%, a 100% elongation stress of 0.3 to 1.0 cN / dtex, and a 120 ° C dry heat shrinkage of less than -1.0%. The method of claim 1, A heat-adhesive composite fiber which is a core-sheath type composite fiber in which a fiber-forming resin component constitutes a core component and a heat-adhesive resin component constitutes a sheath component. The method of claim 1, The heat-adhesive composite fiber whose heat-adhesive resin component is polyolefin resin. The method of claim 1, The heat-adhesive composite fiber whose heat-adhesive resin component is crystalline co-polyester. After cold drawing undrawn yarn drawn at a spinning speed of 1300 m / min or less at 1.05 to 1.30 times, the relaxation heat shrinkage was performed at a temperature of 10 ° C. or more higher than both the glass transition point of the heat-adhesive resin component and the glass transition point of the fiber-forming resin component. The manufacturing method of the heat-adhesive composite fiber of Claim 1 characterized by the above-mentioned. 6. The method of claim 5, A method for producing a heat-adhesive composite fiber, characterized in that relaxation heat shrinkage is performed in hot air. 6. The method of claim 5, A method for producing a heat-adhesive composite fiber, characterized in that relaxation heat shrinkage is performed in hot water. The heat-adhesive nonwoven fabric whose cantilever value measured by the following method which consists of the self-extension heat-adhesive composite fiber of any one of Claims 1-4 is 10 cm or less: Cantilever value measuring method; The test piece of width 2.5cm and length 25cm is cut out from the web after heat bonding in the machine direction, and the test piece cut out along the board | substrate on the smooth horizontal stage whose one end has a 45 degree slope is placed. Next, one end of the test piece is exactly aligned with the one end of the horizontal side of the horizontal bar (joint part of the slope of 45 degrees and the horizontal bar), and the position of the other end of the test piece is measured as the length from the one end of the slope side of the 45 degree. Since the length of the test piece is 25 cm, this value is 25 cm. Next, the test piece is slid gently in the slope direction, and when the center point of one end of the test piece reaches the same plane as the slope, the position of the other end is measured as the length from the slope side end of 45 degrees. This value is referred to as measured value A. The difference between 25 cm and this measured value A is the cantilever value. Measure the front and back of five test pieces, respectively, and let the average value be the cantilever value of the test piece.