KR960005958B1 - Apparatus for producing thermal bonding polypropylene staple fiber - Google Patents

Abstract

In a compact-type spinning machine for manufacturing monofilament, the cooling device(60) with a space of 30-50mm below the spinneret(10) is placed at the center of yarn way(30), and comprises injection part(51) in the center and holes(52) for cooling air on the top. The cooling air blown at 5-10m/s to the yarn way(30) for holes(52) of cooing air through the injection part(51). Without a conjugate spinning machine, a conjugate yarn in which polypropylene compn. of high and low molecular weight has sea and island morphology can be made by controlling the oxidation speed of filament surface with temp. of spinneret and cooling air.

Description

Equipment for manufacturing polypropylene short fibers for heat fusion

1 is a structural diagram of a conventional compact spinning device

2 is a structural diagram of cooling means used in the apparatus of the present invention.

3 is a structural diagram of the apparatus of the present invention provided with the cooling means of FIG.

* Explanation of symbols for main parts of the drawings

10: detention 29: cooling wind

30: Apostle 40: cooling interval

50: cooling means 51: cooling wind injection unit

52: cooling wind hole 53: cooling grinding

The present invention relates to an apparatus for producing polypropylene short fibers for heat fusion, and more particularly, to a compact spinning apparatus for manufacturing a composite yarn short fiber by adjusting the structure, setting position and cooling air of the cooling means. .

In general, nonwoven fabrics made from short polypropylene substrates are excellent in chemical resistance, heat processability, oil absorption, low hygroscopicity and antibacterial properties, and the thickness of molded products is easily from 0.1 mm thick to 10 mm thick. As it can be molded, the thickness is thin, such as seed coating material, packing, medical, bedding, furniture, medical hygiene material, filter, etc., and the thick one is oil adsorbent, separation of water and sand, soil improvement, road construction, etc. It is widely used as a civil engineering material.

Polypropylene, which is used as a substrate for polypropylene nonwoven fabrics, is particularly used as a heat-sealed short fiber because of its low melting temperature and low cost.

Generally, as a method of improving the heat fusion property, a method of using a sea island-type composite yarn in which a low melting point polymer such as polyethylene is located outside, a method of mixing a certain ratio of binder fibers in the production of nonwoven fabric, and polymer mixing The technique may be used.

For example, in the method using a nonwoven fabric body fiber such as Japanese Patent Application No. 61-10583, it is difficult to distribute the binder fibers uniformly in the nonwoven fabric because the binder fibers serve as the heat fusion fibers to facilitate heat fusion. In addition, the manufacturing cost is high because the cost is high, and if the content of the provider fibers is too large, there is a disadvantage that the inherent properties of the nonwoven fabric are not obtained, and also the binder fiber itself may have a disadvantage of physical properties such as touch.

Japanese Patent Laid-Open No. 62-26977, Japanese Patent Laid-Open No. 3-287818, Japanese Patent Laid-Open No. 1-30942, Japanese Patent Laid-Open No. 53-134963, Japanese Patent Laid-Open No. 52-12830, Japanese Patent Laid-Open No. 4-18121, etc. Likewise, the method of improving the heat sealability by using a composite spinning technique of positioning a low melting point polyethylene and a polymer in an island can control the heat sealability arbitrarily and can also easily heat seal to lower the heat welding temperature when manufacturing the nonwoven fabric. And, there is an advantage that can make a fabric excellent in strength and touch.

In general, the structure of the fiber having the most excellent heat sealing property in the heat treatment process when manufacturing the nonwoven fabric is a composite yarn. For example, in the island-in-the-sea composite yarn, if the center portion is made of polyester and the outer portion is made of polyethylene, a nonwoven fabric having very excellent physical properties can be produced. That is, the polyethylene component of the skin portion can be fused at low temperatures in the nonwoven fabric manufacturing heat treatment process, and heat fusion is very easy because the melted polymer has good flowability at the same temperature. On the other hand, the polyester component located in the core part hardly deteriorates even at the heat fusion temperature of the skin region, and thus the physical properties of the nonwoven fabric are surprisingly improved since the fiber-like structure can be maintained up to the nonwoven fabric.

However, this composite spinning technology is very difficult, and also requires a lot of equipment investment costs, the number of detainers per unit area has a disadvantage of poor productivity.

The present inventors endeavored to make the structure of the composite yarn as described above by using the simplest and most economical method without using the difficult and difficult technique of composite spinning. It has been found that the temperature of the metal impregnation allows the surface portion of the polymer strip to be rapidly oxidized to form a low molecular weight polypropylene component on the surface portion of the final yarn to give a structure similar to that of the spun yarn. On the basis of this fact, the invention has been filed as a Korean Patent Application No. 93-22974 for the method of manufacturing the polypropylene short fibers for heat fusion.

On the other hand, in the production of short polypropylene fibers, compact spinning equipment is used to reduce the space occupied by the production equipment. Conventional compact spinning equipment releases the cooling wind 20 at a high rate of about 30 m / s at about 1 to 2 mm directly below the detention 10, as shown in FIG. 1, to rapidly cool the polypropylene melt. It is designed.

The inventors of the present invention have applied the method of Patent Application No. 93-22974, which was invented by the inventors, to manufacture such a polypropylene short fiber for heat fusion with simple and high productivity. As a result, the inventors of the Patent Application No. 93 In order to apply the method of -22974 to compact spinning equipment, the polypropylene melt is extruded from the mold and maintained at a temperature of 300 ℃ or more while traveling a certain distance to cause oxidation reaction by oxygen in the air. The point where the propylene melt starts to be cooled by the cooling wind (hereinafter referred to as the "cooling interval") should be at least 10 mm below the detention. However, in the conventional compact spinning equipment, when the cooling interval is 5 mm or more, The apostle shakes or breaks, and radiation is impossible, and the cooling interval is 10 In this case, the axle is shaken or broken due to the high speed of the cooling wind. Therefore, the speed of the cooling wind must be lowered. If the speed of the cooling wind is lowered, the polypropylene melt extruded from the detention cannot be sufficiently cooled. In order to increase the time, it has been found that the length from the top of the cooling means to the bottom of the cooling air discharged to the outside of the device (hereinafter referred to as the "cooling length") has to be increased. The company has developed a compact spinning device for the production of worn polypropylene short fibers.

Therefore, according to the present invention, in the compact spinning apparatus provided with the cooling means, the cooling means is disposed in the center of the apostle with a cooling interval of 30-50 mm under the detention, and a cooling wind injection portion is formed at the center of the cooling means, and There is provided a plurality of cooling wind holes are provided, the apparatus for producing polypropylene short fibers for heat fusion, characterized in that the cooling air is designed to supply to the dead road from the cooling wind hole via the cooling wind inlet.

Moreover, in this apparatus, the speed of the cooling wind supplied from the cooling means to the slope is adopted to maintain the range of 5-10 m / s.

The apparatus of the above-mentioned feature is to oxidize the surface portion of the polymer strip at a high rate by heating the detention temperature at the time of spinning of the melt of polypropylene to form a low molecular weight polypropylene component on the surface portion of the final yarn for thermal fusion. It is suitable for applying the method of patent application 93-22974 to produce polypropylene short fibers.

That is, when the compact spinning device of the present invention is used, a polypropylene melt is easily oxidized in the air as a method of making a composite yarn in which a polymer and a low molecular weight polypropylene component exist in an island-in-the-sea form without using a composite spinning production apparatus. It is possible to produce island-in-the-sea composite yarn-like short fibers by controlling the oxidation rate with the temperature of detention and cooling wind by using the properties. Propylene is formed, and the core portion of the fiber is formed of a composite yarn form in which high molecular weight polypropylene is present without being affected by oxidation.

Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings.

As shown in FIG. 2 and FIG. 3, in the manufacturing apparatus, the cooling means 60 is disposed at the center of the slope 30 with a cooling interval 40 of 30 to 50 mm below the cap 10. As shown in FIG. Cooling air inlet 61 is formed in the central portion of the cooling means 60, and a plurality of cooling air holes 62 are formed in the upper portion, so that the cooling wind 20 passes through the cooling air inlet 61. It is designed to supply to the dead road 30 at a speed of 5-10 m / s at 62.

In this apparatus, the cooling interval 40 is preferably 30 to 50 mm below the detention 10. If the cooling interval 40 is less than 30 mm, the decomposition rate of the polypropylene is too slow to form a low molecular weight skin layer. In addition, the cooling interval 40 is greater than 50mm and the amount of skin formation is increased, the content of the core is relatively reduced, the physical properties of the nonwoven fabric is poor.

In addition, the cooling wind speed is preferably 5 to 10 m / s. If the cooling wind speed is less than 5 m / s, the polypropylene melt is not sufficiently cooled and the concentration of yarn is impossible, and when the cooling wind speed is greater than 10 m / s, the apostle is shaken by the cooling wind. The company's connection is impossible.

In addition to increasing the cooling interval and setting the speed of the cooling wind as described above, it is also necessary to lengthen the time for the cooling wind to contact the polypropylene melt in order to ensure sufficient cooling of the polypropylene melt extruded from the cap. For this purpose, it is preferable to lengthen the length of the cooling length 63 of the cooling means 60, that is, from the uppermost end of the cooling means 60 to the lowermost cooling hole 62 where the cooling air is discharged to the outside of the apparatus. The cooling length 63 suitable for this apparatus is in the range of 30 to 50 cm. If the cooling length 63 is less than 30 cm, there is a problem that the cooling wind speed must be increased for sufficient cooling. The problem of lowering process stability due to subcooling occurs.

The short fibers produced in this apparatus have a melt flow index (MI) higher than the melt flow index of polypropylene as a raw material resin. The melt flow index of short fibers showing good strength and softness in nonwoven fabrics is 30 to 60. If the melt flow index of the short fibers is less than 30, that is, if the skin content is small, it may not be able to exert the effect of the abdomen. Therefore, the heat fusion temperature must be increased when manufacturing the nonwoven fabric. The strength and the softness worsen. When the melt flow index of the short fibers is greater than 60, that is, when the skin content is large, the core content is relatively low. Thus, as in the above case, short fibers having a low molecular weight are produced without the characteristics of the composite yarn. It can only lower the thermal fusion temperature when manufacturing the nonwoven fabric, but the physical properties of the nonwoven fabric is worse. Therefore, the melt flow index of the short fibers is advantageously 30 to 60.

Polypropylene short fibers produced by the present invention as described above is very excellent in heat sealability can lower the temperature of the heat welding temperature when manufacturing nonwoven fabric and also can increase the speed of nonwoven fabric production is very high productivity as well as single spinning It is very economical as the facility can obtain the compound spinning effect.

The short fibers of the polypropylene of the present invention can be used in any application for thermal fusion, but is particularly suitable for high value-added products requiring a soft touch, such as diapers and sanitary products.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to the Examples described below.

The physical properties measured in the following Examples and Comparatives were evaluated by the following method.

Melt Flow Index (Melt Index, MI): Expressed in g / min based on ASTM D-1238.

Tensile strength of nonwoven fabric: Based on the strip method of JISL-1096, it evaluated by the test piece of width 30mm and length 100mm.

Softness: A nonwoven fabric is obtained by heat-treating a 30g / m3 web obtained at a discharge rate of 100mpm with a high speed card machine at 140 ° C for 20 seconds under a condition of 25 ° C 65% RH, and evaluating the obtained nonwoven fabric by ten tactile judgment. It was.

Ex) 10: 10 people are judged good

4: 4 out of 10 judged good

Example 1

In the apparatus of FIG. 3, the high-molecular-weight polypropylene resin consisting of the polypropylene component whose MI is 10 was extruded and spun at the detention temperature of 310 degreeC, and the undrawn yarn of 90,000D / 30,000F was obtained. At this time, the cooling interval 40 was 45 mm, and the cooling wind speed was 9 m / s.

This undrawn yarn was drawn to a draw ratio of 1.5 and a drawing temperature of 70 ° C. in a subsequent step, and crimped, dried and cut to short fibers. MI of this short fiber was 40. Using this short fiber, a nonwoven fabric was produced by the conventional method.

Evaluation: The nonwoven fabric produced was very excellent in heat sealability, and was excellent in tensile strength in the width direction of the final nonwoven fabric in 2.5 kg and softness of 10.

Comparative Example 1

It carried out similarly to Example 1 except having used the apparatus of FIG.

Evaluation: The production of short fibers was unsuccessful due to the shaking of the apostles, which made it impossible to focus the yarns.

Comparative Example 2

It carried out similarly to Example 1 except having set the speed of cooling wind to 3 m / s.

Evaluation: The polypropylene melt was not sufficiently cooled and the yarns could not be focused, thus failing to produce short fibers.

Comparative Example 3

It carried out similarly to Example 1 except having set the speed of cooling wind to 12 m / s.

Evaluation: The production of short fibers was unsuccessful due to the shaking of the apostles, which made it impossible to focus the yarns.

[Comparative Example 4]

The same procedure as in Example 1 was conducted except that the cooling interval was 60 mm.

Evaluation: The MI of the final short fiber was 80. Thermal fusion was good when manufacturing the nonwoven fabric, but the tensile strength in the width direction of the nonwoven fabric was poor at 1.5 kg, and the flexibility was also poor at 3.

[Comparative Example 5]

The same procedure as in Example 1 was conducted except that the cooling interval was set to 20 mm.

Evaluation: The final short fiber had a MI of 22. Thermal fusion was good when manufacturing the nonwoven fabric, but the tensile strength in the width direction of the nonwoven fabric was poor at 1.3 ㎏, and the flexibility was somewhat poor at 8.

Claims (2)

In the compact spinning device for producing polypropylene short fibers for heat fusion having a cooling means (60), the cooling means (60) has a cooling interval (40) of 30 to 50 mm below the detention (10). Is disposed in the central portion of the cooling means 60, the cooling air injecting portion 61 is formed in the central portion of the cooling air injection hole 61 is formed by a plurality of cooling wind holes (62) in the upper portion. The apparatus for producing polypropylene short fibers for heat fusion, characterized in that it is designed to be supplied to the dead road 30 in the cooling wind hole (62) via. 2. The apparatus for producing polypropylene short fibers for thermal fusion according to claim 1, wherein the cooling wind (20) has a speed of 5 to 10 m / s.