JP2775476B2 - Composite type heat-bondable fiber and nonwoven fabric using the same - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a composite adhesive fiber and a nonwoven fabric using the same.

(Prior Art) In recent years, with the diversification of nonwoven fabric applications, the performance required of nonwoven fabrics has also been advanced, and there has been a demand for nonwoven fabrics that maintain high nonwoven fabric strength with as little nonwoven fabric weight as possible and have a soft texture. In order to satisfy such demands, the nonwoven fabric should be composed of composite type heat-adhesive fibers having the finest possible fineness.
In addition, it is necessary that the low melting point component of the composite type heat-adhesive fiber that contributes to heat bonding is flexible and has high tensile strength. Japanese Patent Publication No. Sho 61-10583 discloses a nonwoven fabric using a composite type heat-adhesive fiber having a fineness using a linear low-density polyethylene having low rigidity (hereinafter abbreviated as L-LDPE). Power is still not enough. Further, when such L-LDPE is used, there is a disadvantage that yarn breakage is apt to occur in the spinning / drawing step when trying to obtain a composite type heat-adhesive fiber having a fine fineness.

(Problems to be Solved by the Invention) The present invention is to obtain a composite type thermo-adhesive fiber which does not have these disadvantages of the prior art, that is, has a fine fineness, has no thread breakage, and has a good texture, and such a composite type thermo-bonding An object of the present invention is to obtain a nonwoven fabric having high nonwoven fabric strength and soft texture using conductive fibers.

(Means for Solving the Problems) The present inventor has conducted intensive studies to improve the above-mentioned problems of the conventional composite-type heat-adhesive fiber and the nonwoven fabric using the same,
The present inventors have found that the intended purpose can be achieved by using a special L-LDPE as the first component of the composite heat-bonded fiber, and have reached the present invention. That is, the present invention provides a composite spinning of two types of thermoplastic resins having different melting points of 20 ° C. or more in a core-sheath type or a parallel type so that a resin having a low melting point communicates at least a part of the fiber surface. In the composite heat-bondable fiber thus obtained, the low-melting-point thermoplastic resin (first component) is a copolymer containing ethylene as a main component and α-olefin having 3 to 12 carbon atoms as a copolymer component. Is 0.900 ~ 0.940g / c
m ³ , melt flow rate is 5-45 g / 10 min (ASTM D-123
8) A composite heat-bondable fiber characterized by being an L-LDPE having an endothermic peak other than the melting point in the range of 90 to 125 ° C. of the DSC curve and a nonwoven fabric using the same, .

In the present invention, the melt flow rate of L-LDPE is 5
If the melt flow rate is less than 45, the nonwoven fabric having the desired strength cannot be obtained, and the plasticity is poor. On the other hand, if the density of L-LDPE exceeds 0.940, the degree of crystallinity is high and the hardness is high, so that a nonwoven fabric having a soft feeling cannot be obtained, which is not preferable. The density of L-LDPE is
If it is less than 0.900, the strength of the obtained fiber is reduced, and the nonwoven fabric also has a low strength, which is not preferable.

L-LDPE used in the present invention has a 90% of its DSC curve.
There must be an endothermic peak other than the melting point in the ~ 125 ° C region. If the position of the endothermic peak other than the melting point is less than 90 ° C, the target nonwoven fabric strength cannot be obtained, and if it exceeds 125 ° C, the nonwoven fabric bonded at low temperature lacks the strength, and therefore cannot be used .

Here, the DSC curve is a sampling rate of 5 mg and a scanning speed of 1 according to JIS K 7121 (Plastic transition temperature measuring method).
6 is a differential scanning calorimetry curve measured at 0 ° C./min.
When the obtained DSC curve has a plurality of endothermic peaks, the main peak is taken as the melting point, and the other peaks are taken as endothermic peaks other than the melting point.

In the present invention, a thermoplastic resin having a melting point higher than that of the first component by 20 ° C. or more, such as crystalline polypropylene (hereinafter abbreviated as PP) and polyethylene terephthalate (hereinafter abbreviated as PET), is used as the second component of the composite thermoadhesive fiber. be able to. The first component and the second component are subjected to composite spinning by a conventionally known method into a core-sheath type or a parallel type so that the first component continuously forms at least a part of the fiber surface. The composite ratio of the first component and the second component is preferably 20 to 80% by weight of the first component and 80 to 20% by weight of the second component. When the amount of the first component is less than 20% by weight, the strength of the fiber can be increased, but the number of fusion points at the fiber contact points is small, and the strength of the nonwoven fabric is reduced, so that a preferable one cannot be obtained. Conversely, if the first component exceeds 80% by weight, the nonwoven fabric has a soft hand, but tends to be bulky, which is not preferable.

The spinning conditions are as follows: the spinning temperature is 180 to 280 ° C. for the first component side, 200 to 300 ° C. for the second component side, a take-up speed of 200 to 1500 m / min, preferably 400 to 1000 m / min, and a draw ratio of 2 to 6 times, preferably 3 to By making it 5 times, a drawn yarn having a desired fineness is obtained. further,
It can be crimped or cut to an appropriate length to form a stable. In order to obtain a nonwoven fabric with a soft texture,
The fineness is preferably 8 denier or less.

The nonwoven fabric of the present invention contains 30% of the above-mentioned composite type heat-adhesive fiber.
It can be obtained by heat-treating the web or tow contained above at a temperature between the melting point of the first component and the melting point of the second component of the composite type heat-bondable fiber. As the fiber that can be mixed with the composite heat-adhesive fiber, synthetic fibers such as polyester and polyamide or cotton as long as it does not soften or deteriorate at the temperature of the heat treatment and can be used as a nonwoven fabric having a good feeling. And any of natural fibers such as wool. When the content of the composite heat-adhesive fiber in the web or the toe is less than 30% (weight), the number of bonding points between the fibers due to the thermal fusion of the first component of the composite heat-adhesive fiber decreases, and Is unfavorable because the strength of the resin decreases. As a heat treatment method, a known method such as a hot air drier, a suction band drier, a Yankee drier, or a hot calender roll can be used.

(Effect of the Invention) The composite adhesive fiber of the present invention has a specific component L-
Since LDPE is used, it is possible to obtain a composite type thermo-adhesive fiber having a fiber degree using a flexible adhesive component. In addition, a nonwoven fabric having high strength and soft feel can be obtained by using the composite type heat-bondable fiber obtained in this manner.

(Examples) The present invention will be described more specifically with reference to examples and comparative examples. In addition, the definition and measurement method of the physical property value used in each example are as follows.

Nonwoven fabric strength (kg / 5cm): According to JIS L 1085 (Test method for nonwoven fabric interlining), a test piece of 5cm x 25cm is sampled in the vertical direction of the sample, and the cutting strength is 10cm between the grips and the tensile speed is 30cm / min. Is measured.

Specific volume (cm ³ / g) Thickness (Am measured under a load of 10 g / cm ²
m) and the basis weight (Bg / m ² ) are determined by the following formula.

Specific volume = (A / B) x 1000 Hand: (1) Sensory test A sensory test was conducted by five panelists, and those judged as soft were evaluated as excellent, and three or four persons judged as soft. Good was evaluated as good if three or more people were judged not to be soft.
Good is indicated by △, and bad is indicated by ×.

(2) Bending stress Place a 15 cm square sample piece on a sample stage with a slit of 10 mm width and 20 cm length such that the center is on the slit and the width direction is perpendicular to the slit. The force (g) required to push the specimen into the slit by a depth of 1 cm is measured using a push plate having a length of 19 cm, a thickness of 2 mm, and a radius of a tip of 1 mm. The measurement is made in two directions: when the direction of the slit and the direction of the nonwoven fabric coincide (CD) and when the direction of the nonwoven fabric is perpendicular (MD). In addition, about the nonwoven fabric used for embossing, a slit width | variety is 5 mm and it measures similarly.

Spinnability: Excellent when there is no thread breakage during continuous spinning for 1 hour using a spinneret with a hole diameter of 0.6 mm and 360 holes. ○, good ○,
Impossibility is indicated by x.

Stretchability: The unstretched tow obtained in the evaluation of spinnability is stretched,
Excellent when single yarn breakage does not occur at a draw ratio of 4.0 times, while single yarn breakage occurs at a draw ratio of 4.0 times, but less than 4.0 times 3.0
In the range of 2 times or more, a sample in which single yarn breakage does not occur is evaluated as good, and a sample in which single yarn breakage occurs even at a draw ratio of 3.0 is evaluated as unsatisfactory.

Example 1 The density was 0.920, the melt flow rate was 8, the melting point peak of the DSC curve was 119 ° C, and the peak other than the melting point peak was 107 ° C,
L-LDPE having butene-1 as a copolymer component is used as a first component (sheath component), PET having an intrinsic viscosity of 0.65 and a melting point of 260 ° C. as a second component (core component), having a pore diameter of 0.6 mm and a pore number of 360. Using a sheath-core type spinneret, the first component was extruded at 220 ° C., the second component was extruded at 280 ° C., and the composite ratio of the first component and the second component was 50:50 to obtain an undrawn yarn. . The obtained undrawn yarn was preheated to 90 ° C., drawn 4.0 times to give a 2 denier drawn yarn, and subjected to crimping of 11 to 13 ridges / 25 mm with a stafer box.
It was cut to 1 mm. This composite short fiber is supplied to a card machine,
A web having a basis weight of 20 g / m ² was heated with a suction band dryer at a temperature of 125 ° C. and a suction wind speed of 1 m / sec for 2 minutes to obtain a nonwoven fabric. Table 1 shows the properties of the composite heat-bondable fiber, and Table 2 shows the properties of the nonwoven fabric.

Example 2 As the first component (sheath component), L having a density of 0.920, a melt flow rate of 30, a melting point peak of the DSC curve of 119 ° C., a beak other than the melting point peak at 107 ° C., and butene-1 as a copolymerization component Under the same conditions as in Example 1 except that LDPE was used, a composite heat-adhesive fiber and a nonwoven fabric using the same were obtained. Table 1 shows the properties of the composite heat-bondable fiber, and Table 2 shows the properties of the nonwoven fabric.
These are shown in the table.

Example 3 Density 0.910, Melt flow rate 8, DSC curve melting point peak at 119 ° C, peak other than melting point peak at 107 ° C,
Same as Example 1 except that L-LDPE having octene-1 as a copolymer component is a first component, PP having a melt flow rate of 15 and a melting point of 165 ° C. is a second component, and both components are arranged in parallel. To obtain a composite type heat-adhesive fiber. This composite adhesive fiber was heat-treated under the same conditions as in Example 1 to obtain a nonwoven fabric. Table 1 shows the properties of the composite heat-bondable fiber, and Table 2 shows the properties of the nonwoven fabric.

Example 4 The composite heat-bondable fiber obtained in Example 3 was supplied to a carding machine to form a web having a basis weight of 20 g / m ² , and then heated and compressed by an embossing roll at a temperature of 105 ° C. and a linear pressure of 10 kg / cm. To obtain a non-woven fabric. Table 2 shows the properties of the obtained nonwoven fabric.

Example 5 30% by weight of the composite heat-adhesive fiber obtained in Example 3,
Using a mixed fiber obtained by mixing 70% by weight of a polypropylene fiber having a single fiber fineness of 2 denier, a number of crimps of 15/25 mm, and a fiber length of 51 mm, a web was formed by a carding machine in the same manner as in Example 1, and in the same manner as in Example 4. Heat treatment was performed with an embossing roll to obtain a nonwoven fabric. Table 2 shows the composition of the mixed fiber and the properties of the nonwoven fabric.

Comparative Example 1 Density 0.920, melt flow rate 50, melting point peak of DSC curve was 119 ° C, peaks other than melting point peak were at 105 ° C,
Spinning was carried out under the same conditions as in Example 1 except that L-LDPE containing butene-1 as a copolymer component was used as the first component (sheath component), but satisfactory spinnability was not obtained.

Comparative Example 2 High-density polyethylene having a density of 0.965, a melt flow rate of 8, and a melting point of 132 ° C. (hereinafter abbreviated as HDPE) was used as the first component (sheath component), and the same conditions as in Example 1 were used except that the stretching ratio was 3.0 times. Thus, a composite heat-bondable fiber of 3 denier was obtained. This HD
In the DSC curve of PE, there was no peak other than the melting point. Reduce the temperature of this composite short fiber to 13 with a suction band dryer.
A nonwoven fabric was obtained in the same manner as in Example 1 except that the temperature was changed to 8 ° C. Table 1 shows the properties of the composite heat-bondable fiber, and Table 2 shows the properties of the nonwoven fabric.

Comparative Example 3 DS at a density of 0.935, a melt flow rate of 20, and a melting point of 123 ° C.
L-LDEP having no peak other than the melting point in the C curve was used as the first component (sheath component), and the composite heat-bondable fiber was obtained under the same conditions as in Example 3. A nonwoven fabric was obtained in the same manner as in Example 1 except that the temperature of the suction band dryer was changed to 130 ° C. Table 1 shows the properties of the composite heat-bondable fiber, and Table 2 shows the properties of the nonwoven fabric.

Comparative Example 4 The composite heat-bondable fiber obtained in Comparative Example 3 was supplied to a carding machine to form a web having a basis weight of 20 g / m ² , and then heated and compressed by an embossing roll at a temperature of 105 ° C. and a linear pressure of 10 kg / cm. To obtain a non-woven fabric. Table 2 shows the properties of the obtained nonwoven fabric.

Comparative Example 5 A mixed fiber obtained by blending 10% by weight of the composite heat-adhesive fiber obtained in Example 3 and 90% by weight of a polypropylene fiber was used.
Except for setting the processing temperature to 125 ° C., a web was formed by a carding machine in the same manner as in Example 1, and heat treatment was performed by an embossing roll in the same manner as in Example 4 to obtain a nonwoven fabric. Table 2 shows the composition of the mixed fiber and the properties of the nonwoven fabric.

As is apparent from the data shown in the table, the specific L-
It can be seen that the product of the present invention using LDPE is a nonwoven fabric having a stronger and softer feel than conventional products.

Claims (2)

(57) [Claims] 1. A composite type heat-spun two kinds of thermoplastic resins having different melting points by 20 ° C. or more such that the low melting point resin forms at least a part of the fiber surface in a core-sheath type or a parallel type. In the adhesive fiber, a low-melting thermoplastic resin (first component) is a copolymer containing ethylene as a main component and α-olefin having 3 to 12 carbon atoms as a copolymer component.
Density 0.900 ~ 0.940g / cm ³ , melt flow rate 5 ~ 4
5g / 10min (ASTM D-1238 Condition E), 90% of DSC curve
A composite type heat-bondable fiber, which is a linear low-density polyethylene having an endothermic peak other than the melting point in the range of -125 ° C. 2. The composite type heat-adhesive fiber according to claim 1,
A non-woven fabric having a weight percent or more, and wherein the intersections of the fibers are fixed by fusing the first component of the composite thermoadhesive fiber.