JPS6021213A - Processing method of tip of synthetic resin monofilament - Google Patents

Abstract

PURPOSE:To prevent the tip of a synthetic resin monofilament from discoloring, by a method wherein high temperature region is maintained under inactive gaseous atmosphere when an edge of the tip of the monofilament is made to dull or round by exposing the tip of the monofilament partially in the high temperature region which is more higher than the melting point of said resin. CONSTITUTION:A monofilament 7 whose edge of the tip is either dulled or rounded is obtained continuously by making the tip of a sinthetic resin monofilament 1 pass through a treatment cylinder 2 under a high temperature and inactive gaseous atmosphere for a required period of time. As a processing part of the tip of the monofilament does not discolor almost and heating atmosphere is kept constant due to a matter that a heating region is held under the inactive gaseous atmosphere in this processing method, the tip shape is finished uniformly.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of heat-processing the tip of a synthetic resin monofilament to blunt the tip edge or to make the tip into an enormous spherical shape. More specifically, the present invention relates to a method for manufacturing a monofilament with a tip that has a uniform tip shape and less discoloration.

Synthetic m-lipid monofilament is used for various purposes such as clothing, industrial, fishing, and daily necessities due to its excellent strength, flexibility, and durability, but it is especially used for hair brushes, cleaning brushes, and It has great utility as the tip of brush bristles for polishing brushes, etc. A brush with monofilament bristles at the tip is manufactured by cutting the monofilament to a desired length and planting it on a base, or by joining one end of the monofilament bundle, but the bristles tip of the brush is cut off. If left as is, the tip of the cut end will have a sharp angle, and if this is applied to a hairbrush, for example, it will damage the hair roots and skin. Therefore, in brush applications, it is a major requirement to heat the pre-cut monofilament tip to eliminate blunting of the edge portion or to make it into an enormous spherical shape (sphericalization).

Conventional methods for processing the tip of monofilament include irradiating the tip with a flame or pressing the tip against a heating medium such as a heated metal to locally heat the tip to a temperature above the melting point of the resin. However, in this method, the processed part of the monofilament changes color due to heating.
This tendency is particularly noticeable when processing colored monofilaments. A brush that has been flocked with such discolored processed monofilament will either have a significant discoloration only at the tip of the brush, or the discoloration will progress over time, resulting in poor aesthetic appearance and extremely low commercial value.

Therefore, the inventors of the present invention conducted studies with the aim of preventing discoloration when heating and blunting or rounding the tip of a monofilament as described above. The inventors have discovered that even in the processing of colored monofilaments, processed monofilaments with little discoloration and a uniform tip shape can be obtained, and the present invention has been achieved.

That is, the present invention has the tip of a synthetic resin monofilament,
The edge of the monofilament tip is blunted by locally applying it to a high temperature range above the melting point of the synthetic resin, or
Another object of the present invention is to provide a method for processing the tip of a synthetic resin monofilament, which is characterized in that the high temperature region is maintained under an inert gas atmosphere when the tip is rounded.

The synthetic resin monofilaments used in the present invention include polyamides such as nylon 6, nylon 66, and copolymerized nylon, polyesters such as polyethylene terephthalate, polybutylene terephthalate, and copolymerized polyester, polyolefins such as polyethylene and polypropylene, and polyvinyl chloride and polyfluoride. A melt-extrusion moldable thermoplastic synthetic resin such as polyvinyl halide such as vinylidene chloride is spun using a conventional melt-extrusion spinning method, optionally stretched and heat-set to obtain a wire having a wire diameter of 0.1 to 3. Om monofilaments, and additives such as heat resistant agents, weather resistant agents, antioxidants, flame retardants, lubricants, plasticizers, abrasives, and colorants can be added to the synthetic resin forming these monofilaments. In particular, when a monofilament whose synthetic resin contains a colorant is subjected to the conventional tip processing method, the discoloration of the processed part is significant, but the method of the present invention significantly improves the discoloration of monofilament products containing a colorant. It is characterized by:

These monofilaments and ment are usually cut to a desired length and subjected to tip processing, but as they are cut, they have a tip shape as shown in Figure 1 (a), with an acute edge. However, if this is applied directly to the brush bristles, it is likely to damage the object. Therefore, the present invention proposes to locally heat-process the tip of the monofilament to blunt the tip edge as shown in Figure 1 (B), or to make the tip convex as shown in Figure 1 (C). This is the main idea.

This monofilament tip processing is usually performed by locally exposing the monofilament end to a high-temperature heating region that is higher than the melting point of the resin, but if the heating region is in the air, as mentioned above, the discoloration of the processed tip portion is significant. . However, the present invention is characterized in that the heating area is maintained in an inert atmosphere, and by adding this requirement, the discoloration of the tip processed portion is significantly improved.

Specific means for carrying out the method of the present invention include (
1) A method in which the tip of the monofilament is passed through a processing cylinder in which a high-temperature inert gas flow circulates; (2) A heating medium such as a heating heater or a heating metal plate is placed in the processing cylinder under an inert atmosphere, and the monofilament is placed close to the heating medium. (3) a method in which the tip of the monofilament is lightly pressed against the heating medium in method (2) above, and (4) a method in which method (2) and/or (3) described above is combined with method (1) above. Examples include methods of matching.

Next, the above method (1) will be explained in more detail with reference to FIGS. 2 and 3.

FIG. 2 is a plan view of an apparatus for carrying out the above method (1), and FIG. 3 is a longitudinal sectional side view thereof.

Pre-cut monofilament l in the drawing
is held or placed on a supply means such as a conveyor bell 1- (not shown), and is continuously supplied so that only its tip portion is exposed to the inside of the processing cylinder 2 through the insertion port 3 of the processing cylinder 2. A heating cylinder 4 having a heat medium 5 such as a heating heater is provided at the bottom of the processing cylinder 2, and an inert gas supply source 6 such as a nitrogen gas cylinder is further installed at the bottom of the heating cylinder 4. . The inert gas rises in the direction of the arrow from the supply source 6, is heated in the heating cylinder 4 to a temperature higher than the melting point of the resin forming the monofilament, and then advances into the processing cylinder 2, creating a high-temperature inert atmosphere inside the processing cylinder 2. After forming, it is discharged from the insertion port 3 of the processing cylinder 2. The area around the monofilament supply means is sealed and communicated with the inert gas supply source 6, and the inert gas is circulated within the system using a pump or blower installed in the supply source 6 to prevent the inert gas from escaping. It is also possible to configure the system so that it can be prevented and used effectively.

Processing cylinder 2 under a high temperature inert atmosphere formed in this way
By passing the tip of the monofilament 1 for a desired time, processed monofilaments 7 with blunted or rounded tips can be continuously obtained.

In this processing method, the heating area is kept under an inert gas atmosphere, so the processed part of the monofilament tip hardly changes color, and since the heating atmosphere is kept constant, the tip shape is finished uniformly. This effect can be obtained.

In addition, method (2) above is a method in which the heating medium 5 shown in FIG. The above method (3) is a method in which the tip of the monofilament 1 is lightly pressed into contact with the heating medium 5 in the above method (2) to mainly form a rounded tip.

In addition, in the method of the present invention, the size of the tip ball can be arbitrarily selected based on the degree of processing of the tip, that is, the blunting of the edge, by appropriately adjusting the time during which the monofilament tip remains in the heating cylinder, the heating temperature, etc. can.

As explained above, according to the method of the present invention, a processed monofilament with a uniform tip shape and a blunted or rounded tip edge with little discoloration can be efficiently produced, and the processed monofilament obtained is particularly It is useful as a brush bristles tip with improved texture.

The effects of the present invention will be further explained below with reference to Examples.

Example Nylon 66 (CM3001 manufactured by Toshiku Co., Ltd.) alone (natural) or as a coloring agent manufactured by Fuji Titanium Co., Ltd.
manufactured by Yamaba Kako Co., Ltd., containing 0.3% by weight of titanium oxide TA-100 (white), and 0.3% by weight of titanium oxide TA-100 manufactured by Yamaba Kako Co., Ltd.
3% by weight (pink), 0.3% (green) of fucrocyanine pigment manufactured by Sanyo Kako Co., Ltd. and Yamaba Kako Co., Ltd.
Five types of materials each containing 0.26% by weight (blue) of anthraquinone-based dye were subjected to the usual melt spinning method to produce natural, white, pink, green, and blue materials each with a wire diameter of 0.6H. Five types of monofilaments were obtained and cut into 5α lengths.

Next, each monofilament was held on a conveyor at equal intervals, and the leading end was continuously passed through the processing tube of the apparatus shown in FIGS. 2 and 3.

The processing temperature of the heating cylinder was about 450° C., nitrogen gas was used as an inert gas, and the residence time of the monofilament tip in the processing cylinder was 1.5 seconds.

The obtained processed monofilament has a tip of about 0.75 to 0.
．． The tip is 80 MM, and there is almost no discoloration when seen with the naked eye.

Table 1 shows the results of a colorimetric test performed on each monofilament l and the tip before and after the tip processing using an 8M color computer manufactured by Suga Test Instruments Co., Ltd.

For comparison, the tip of a monofilament obtained by sending high-temperature air into the heating cylinder instead of nitrogen gas and processing the tip in the same way was clearly discolored when inspected with the naked eye, and the colorimetric test results were as follows. As shown in Table 1, the results were inferior.

Table 1 *) L - Lightness, a, b - Perceptual Color Index, ΔE - Color Difference Each measured value is the test result of 5 samples.

As is clear from the results in Table 1, according to the method of the present invention (heating in a nitrogen gas zone), the tip processing part glue, a, b
A processed monofilament with values of ΔE and ΔE close to those of the monofilament before processing and little discoloration as a whole can be obtained. On the other hand, heating in air can only yield processed monofilaments that are significantly discolored.

[Brief explanation of drawings]

FIG. 1 is a side view of the end of the nofilament, in which (a) is shown when cutting, (b) is when the taper portion is dulled, and (c) is when the tip is processed to be rounded. FIG. 2 is a plan view of the apparatus used in the processing method of the present invention,
FIG. 3 is a longitudinal sectional side view thereof. 1-monofilament, 2-processing cylinder, 3-insertion port, 4-
Heating cylinder, 5 - heat medium, 6 - inert gas supply source, 7 - processed monofilament patent applicant Toshi Monofilament Co., Ltd. Figure 1 (A) (C)) (/S

Claims (1)

[Claims] When the tip of a synthetic resin monofilament is locally exposed to a high temperature region higher than the melting point of the synthetic resin to blunt the edge of the monofilament tip or to make the tip into an enormous sphere, the high temperature region is exposed to an inert gas atmosphere. A method for processing the tip of a synthetic resin monofilament, which is characterized by holding the tip.