KR910006428B1 - Thermo-adhesive pon woven fabric - Google Patents

Abstract

High-density polyethylene fiber of h.d. polyethylene which satisfies the following condition; (a) density(g/cm3); 0.941-0.960 (b) Q (weight average mol w.t./number average mol. w.t.); below 10.0 (c) melting point; 120-140 deg.C or composite fiber of which above mentioned high density polyethylene fiber forms the outer portion (e.g. sheath side), the core portion is made of polypropylene with the melting point move than 20 deg.C above that of high density polyethylene fiber, and the alignment is pararrel or core-sheath type, is heat-bonded with other fibers to form heat- adhesive nonwoven.

Description

Thermal Adhesive Nonwoven

The present invention relates to a heat adhesive nonwoven fabric. More particularly, the present invention relates to a heat adhesive nonwoven fabric thermally bonded with polyolefin fibers.

As a method of joining fibers together in the manufacture of nonwoven fabrics, such as a needle punch method, a mechanical method of entanglement between fibers, a chemical method using various binders, and a heat treatment after mixing a relatively low melting point powder or fibrous solid into the nonwoven fabric fibers And the thermal bonding method for bonding the fibers together.

In recent years, the demand for paper diapers, sanitary products repellents, medical uses, and nonwoven fabrics for padding materials such as quilts and quilting garments require hygiene, soft texture, low apparent weight and high strength. Since the necessity of saving and improving the working environment is urgently required, the thermal bonding method is widely used for nonwoven fabric manufacturing.

In particular, the heat-adhesive fibers can be mixed uniformly with the constituent fibers of the nonwoven fabric, and can be simply thinned and have good yields.

Conventionally used thermal bonding binders include low melting point polyester, polypropylene, or polyethylene, etc., but have properties such as hygiene, soft feel, low apparent weight, high strength, good radioactivity and elongation. Only polyethylene is equipped. However, low-density polyethylene and linear low-density polyethylene can be expected to have a soft touch due to low toughness, but due to poor bagability and elongation, it was impossible to make a heat-adhesive fiber, and thus mainly used in powder form.

The present inventors have studied diligently to overcome the above-mentioned drawbacks. As a result of the intensive study, the density is 0.941 g / cm 3 to 0.960 g / cm 3, the Q value (Q = Mw / Mn) is 10.0 or less, and the melting point is in the range of 120-140 ° C. With the fact that polyethylene is also excellent in bagability, it has been found that a composite fiber which continuously forms at least a part of the fiber surface can be preferably used as a heat-sealed binder fiber and has completed the present invention.

The high-density polyethylene used in the present invention is generally known as a linear polymer because there is almost no branched chain of monomers as a polymer pendant from the polymer main chain, and the reason for limiting the density to 0.941 g / cm 3 to 0.960 g / cm 3 is 0.941 g. If less than / cm3, the crystallinity is low, so soft texture can be obtained, but the radioactivity, elongation, and strength are lowered. If the density is higher than 0.960g / cm3, the crystallinity is too high, the strength is improved, but it can be obtained by thermal bonding treatment. This is because the nonwoven fabric has a drawback that tends to be hard. The reason for limiting the Q value to 10 or less is that when the Q value is larger than 10, the width of the molecular weight distribution becomes too large, resulting in degradation of physical properties such as strength and elongation at the time of manufacturing the heat-adhesive fiber, which is not suitable for use as a heat-adhesive fiber. Q value is a ratio of the weight average molecular weight (Mw) and number average molecular weight (Mn) obtained by the gel permeation chromatography method, ie, Q = Mw / Mn.

The reason why the melting point of the high-density polyethylene used in the present invention is limited to 120-140 ° C. is because if the melting point is lower than 120 ° C., the heat resistance of the manufactured nonwoven fabric is lowered. If the melting point is higher than 140 ° C., the heat treatment cost for fusion is too high. Because.

Stabilizers, colorants, fillers, and the like, which can be normally added to polyethylene, can be added to the high density polyethylene within a range that does not impair the object of the present invention.

The high density polyethylene thus obtained can be spun on its own and can be spun together with other fibrous polymers.

Examples of other fiber-forming polymers capable of complex spinning are polypropylene, polyester and the like. The composite type can be either parallel or super-core, but in order to achieve the heat-bonding effect of high-density polyethylene, the high-density polyethylene must form at least a portion of the fiber surface continuously in the parallel type, and the high density in the super-core type. It should be arranged so that it is a supercomponent of polyethylene.

It is preferable that the melting point of polypropylene, polyether, etc., which are other fiber-forming polymers capable of complex spinning with the high-density polyethylene of the present invention, is 160 ° C or higher. The reason is that when the difference between the melting point of the core component and the melting point of the initial component is 20 ° C. or lower, the strength, which is the basic performance of the core component, decreases due to heat during heat treatment, which will be described below. This is because the shape stability is lowered. In addition, polypropylene is superior to polyester in fiber-forming polymerization complex spinning with high density polyethylene. Because the combination of the high-density polyethylene and polyester of the present invention, the composite yarn and the stretched yarn have a large difference in the solubility parameters, so that the core and supercomponents are separated, and the high density polyethylene and the polypropylene have almost similar solubility parameters. This is because the separation between the core and supercomponents is not expressed during complex spinning and stretching.

High density polyethylene fibers used in the present invention can be produced as follows. That is, in the case of single spinning, the spinning temperature is radiated at 200 to 280 ° C. and the winding speed is 800 to 1500 m / min, and the stretching temperature is 80 to 110 ° C. and the drawing ratio is 2-5 times. Stability fibers can be obtained stably. In the case of composite spinning, the spinning and stretching conditions vary depending on the relative component to be composited, but the spinning temperature of the high-density polyethylene side of the present invention is suitably 200 to 280 ° C. This can be set according to the conditions.

The heat-adhesive fiber used in the present invention is mixed and molded with other fibers constituting the nonwoven fabric by a method such as a wet papermaking method or a cutting web method, and a temperature of 130 to 150 ° C by a method such as hot air, superheated steam, infrared rays, or a thermal roller. It is heat-treated at and becomes the heat adhesive nonwoven fabric of this invention.

Fibers constituting the nonwoven fabric include one or two or more kinds of chemical fibers such as natural fibers such as pulp, cotton, and wool, viscose rayon, polyolefin fibers, polyester fibers, and polyamide fibers, depending on the purpose of the nonwoven fabric. You can choose to use it.

The amount of the heat-adhesive fiber needs to be 10% by weight or more based on the total amount of fibers after mixing, and 40% by weight or more is preferable when the strength of a large nonwoven fabric is required.

Since the heat-adhesive fiber used in the present invention is fibrous, it is not only easy to uniformly mix with other kinds of fibers, but also has a small fineness because of low fineness, and also has a low melting point, thereby reducing energy costs during heat treatment. And the like. As a method of forming a composite fiber alone or a mixture of composite fibers and other fibers into a fiber aggregate, a known method generally used in the production of nonwoven fabrics. For example, any of a guide method, an airlay method, a dry pulp method, a wet grass method and the like can be used.

As a heat treatment method for performing the fiber assembly to nonwoven fabric by thermal fusion of the low melting point component of the composite fiber, any one of a dryer such as a hot air dryer, a color hand drum dryer, a Yanki dryer, a flat calender roller, an ambo roller, a heat roller, and the like. You can also use the method.

The invention is further illustrated by examples and comparative examples. The test and evaluation method used in each example is as follows.

* Single Spinning: The given polyethylene is fed to a spinning extruder. After spinning at an extrusion amount of about 200 g / min using a spinneret having 320 holes, an undrawn yarn was obtained, and then stretched at a predetermined magnification by a thermal roller method.

* Composite spinning: The extrusion amount of each composite part is adjusted according to a predetermined compound ratio using a composite spinning extruder. The spinning and drawing are carried out under the same conditions as the single spinning except for the parallel or super radial spinning nozzle.

* Evaluation of bagability: It is evaluated by the number of times of uncut yarns per hour. It is expressed as 0 times ◎, 1 time ○, 2 times △, 3 times or more ×.

* Extensibility evaluation: It is good that no single cutting is not occurred at all by continuous operation of 1 hour, and it is good that the occurrence of single cutting is three times or less, and it is impossible that the winding operation stops more than one time in the stretching roller because there are many single cutting. It evaluates and marks with (double-circle), (triangle | delta), and x, respectively.

* Evaluation of the separability of complex components: After complex spinning and stretching, the cross-sections were randomly observed 50 times under a microscope. The separated case is indicated by x.

* Tensile strength: According to the test method of tensile strength and elongation of JIS L 1085 (nonwoven fabric wicking test method), a sample of 5 cm in width and 20 cm in length was captured and measured at an interval of 10 cm and a tensile rate of 30 ± 2 cm per minute.

* Non-woven fabric touch: When the sensor is tested by five parenas and the power is judged to be soft, ○ When three or more people judge that it is soft, △ It evaluated by x.

[Example 1-2, Comparative Example 1-6]

Using various polyethylenes, heat-adhesive fiberization was carried out under the spinning conditions and stretching conditions shown in Table 1-2 in Table 1-1, followed by the evaluation of bagability and stretchability. The heat-adhesive fibers are cut to short fibers, mixed with other fibers, and heat treated to obtain a nonwoven fabric. The mixing conditions, nonwoven fabrication conditions and the characteristics of the obtained nonwoven fabric are shown in Table 1b.

Table 1-1

TABLE 1-2

(Where d is Denier)

Example 3-4 and Comparative Example 7-12

Various fiber-forming polymers are combined for various polyethylenes to obtain heat-adhesive composite fibers. The composite components, composite forms and composite ratios of the composite fibers, spinning conditions, stretching conditions, evaluation of bagability, evaluation of stretchability, and evaluation of separability of the composite components are shown in Table 2-1.

The heat-adhesive composite fiber is cut into short fibers, mixed with other kinds of fibers, and heat treated to obtain a nonwoven fabric. The mixing conditions, the nonwoven fabrication conditions and the characteristics of the obtained nonwoven fabric are shown in Table 2-2.

TABLE 2-1

Table 2-2

HDPE: High Density Polyethylene

LDPE: Low Density Polyethylene

LLDPE: Linear Low Density Polyethylene

PET: Polyester

PP: Polypropylene

Claims (4)

It is characterized by using a high density polyethylene fiber made of a high density polyethylene satisfying the following conditions, or using a composite fiber in which the high density polyethylene component forms the surface of the fiber, heat-bonding the fiber with other fibers Thermal adhesive nonwovens. Below a) Density (g / cm 3): 0.941-0.960

: 10.0 or less c) Melting Point: 120-140 ℃ The heat-adhesive nonwoven fabric as claimed in claim 1, wherein the composite fiber comprises a high-density polyethylene component and a polypropylene component having a melting point of 20 ° C or higher than the component. The heat-adhesive nonwoven fabric according to claim 1, wherein the composite fiber has a parallel or super-core shape. 3. The heat-adhesive nonwoven fabric as claimed in claim 2, wherein the composite fiber is a core composite fiber comprising polypropylene as a core component and the high density polyethylene as a core component.