JP2011208321A - Method for producing fiber - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a fiber, capable of maintaining stably extruding a relevant polymer over a long period of time; that is, to provide the method for producing the fiber, capable of extending spinneret cleaning time intervals, and also prevented from yarn breakages, and affording well-shaped bobbins.SOLUTION: The method for producing a fiber is provided, comprising the following process: in making a melt spinning for the fiber using a thermoplastic resin, the spinneret surface is imparted with a mixed oil including methylphenyl silicone and dimethylphenyl silicone followed by removing part of the mixed oil; and further, the spinneret surface is coated with the mixed oil followed by making the melt spinning.

Description

  The present invention relates to a method for producing a fiber.

Conventionally, melt spinning has been widely practiced as a method for forming a useful fibrous material. However, when a polymer is discharged through the discharge pores of a die, a low molecular compound contained in the polymer or generated by thermal decomposition is discharged finely. It adheres to the vicinity of the hole, and this becomes heat-denatured solidified and deposited with time, and becomes a base stain.
This dirt on the base prevents stable discharge of the polymer from the discharge pores, causing thread breakage during spinning and deterioration of the shape of the take-up bobbin.
In particular, when melt-spinning composite fibers in which the copolyester forms the fiber surface, many copolyesters have a low melting point. Therefore, when compound spinning is performed in combination with polyethylene terephthalate, the spinning temperature is copolymerized. This is a severe temperature condition for polyester. As a result, a low molecular compound is likely to be generated from the copolyester, and the surface of the die is easily soiled.
For this reason, in order to reduce the adhesion of dirt substances to the surface of the die or to remove the dirt substances, a release agent such as methylphenyl silicone is applied and the dirt on the face of the die is scraped using a tool such as a spatula. Taking and cleaning is done.

In addition, for example, a method is proposed in which a mixture of methylphenyl silicone having excellent heat resistance, dimethyl silicone having excellent releasability, and fine silica powder is applied to the surface of the die and spun (patent) Reference 1).
Furthermore, a method has been proposed in which dimethyl silicone having excellent mold release properties is applied to the die surface, and then alkylphenyl silicone having excellent heat resistance is further applied (see Patent Document 2).

Japanese Patent Publication No.54-31530 JP-A-6-57540

However, in the method described in Patent Document 1, since the heat resistance of dimethyl silicone is inferior, the effect is actually inferior to the case of using methylphenyl silicone alone by simply applying dimethyl silicone to the base surface and spinning. In particular, for composite fibers spun using resins having different melting points, the effect is very low, and yarn breakage frequently occurs.
Further, the method described in Patent Document 2 has a drawback in that workability is poor because different types of silicone are used separately. Cleaning the surface of the die requires manpower, and during this time, the yarn cannot be wound up. Therefore, in the production process, there is a demand for a simple method that allows the work to be completed smoothly in a short time. For this reason, it is very inconvenient to use two types of silicone for work, for example, it takes time to change.
However, no one type of release agent has been found at present which exhibits excellent properties in mold release and heat resistance. Therefore, it is required to find a method that is not inferior in releasability and heat resistance with one type of release agent from the work surface.

The present invention was made as a result of intensive studies to solve the above problems,
An object of the present invention is to provide a method for producing a fiber that can prevent the surface of the die from being stained and maintain a stable discharge state of the polymer over a long period of time. That is, an object of the present invention is to provide a method for producing a fiber that can extend the base cleaning interval, suppress yarn breakage, and have a good bobbin shape.

The purpose of the above is to remove a part of the mixed oil containing methylphenyl silicone and dimethylphenyl silicone on the spinneret surface when melt spinning the fiber using a thermoplastic resin, This is achieved by a fiber manufacturing method characterized in that oil is applied to a spinneret surface and then spun.
Among them, the fiber to be melt-spun is a composite fiber composed of a polymer having two or more components, and 40% or more of the periphery of the cross section of the composite fiber is a composite fiber formed of a copolyester having a lower melting point than other components. Is preferred.

The present invention uses the above mixed oil as a mold release agent, and since this is applied twice, it becomes possible to stabilize dimethyl silicone with low heat resistance for a long time,
It has become possible to combine the excellent heat resistance of methylphenyl silicone and the excellent releasability of dimethyl silicone.
As a result, the surface of the die can be prevented from being soiled, and a stable discharge state of the polymer can be maintained for a long time. That is, it is possible to extend the base cleaning interval, to suppress thread breakage, and to improve the bobbin shape.

In addition, according to the present invention, since one type of release agent is used, the trouble of changing the release agent during work can be saved, and workability is also good.

Hereinafter, the present invention will be described in detail.
In the present invention, when a fiber is melt-spun using a thermoplastic resin, a mixed oil containing methylphenyl silicone and dimethylphenyl silicone is applied to the spinneret surface, and then a part thereof is removed to thereby remove the spinneret surface. It is cleaned, and further, the mixed oil is applied to the spinneret surface and spun.

The mixed oil used in the present invention contains methylphenyl silicone and dimethylphenyl silicone. The proportions of these components may be appropriately set. For example, methylphenyl silicone is preferably 40 to 80 parts by weight and dimethyl silicone is preferably 20 to 60 parts by weight.
Further, the viscosity of the mixed oil is preferably 2000 to 8000 cpoise.
The mixed oil may contain other substances such as SiO ₂ .

The method of applying mixed oil may be applied using tools such as brush, brush, cloth, etc.
It is preferable to spray the mixed oil in a spray form so that the mixed oil can be uniformly applied to the surface of the die.
The cleaning method is performed, for example, by rubbing with a spatula or a rod after applying the mixed oil.

As in the present invention, after the mixed oil is applied to the spinneret surface, a part thereof is removed, that is, a part of the mixed oil is left, and the mixed oil is applied to the spinneret surface. It is possible to prevent the surface of the die from being soiled and to maintain a stable discharge state of the polymer for a long time. In other words, it is possible to extend the base cleaning interval,
Further, yarn breakage can be suppressed and the bobbin shape is good.

INDUSTRIAL APPLICABILITY The present invention is extremely useful as a method for producing fibers when melt spinning fibers from thermoplastic resins such as polyester, polyamide, and polypropylene. Among them, the fiber to be melt-spun is
This is particularly useful when the composite fiber is composed of two or more components of polymer, and 40% or more of the cross section of the composite fiber is formed of a copolyester having a lower melting point than the other components. Examples of the low-melting copolymer polyester include polyesters obtained by copolymerizing isophthalic acid, polyethylene glycol and the like.
In particular, good results are obtained when applied to the production of a core-sheath type polyester composite fiber using isophthalic acid copolymerized polyethylene terephthalate as a sheath and regular polyester as a core.

Hereinafter, the present invention will be specifically described with reference to examples. In addition, this invention is not limited to the Example described below.

[Example 1, Comparative Examples 1-3]
For each silicone type and method used for cleaning the base surface, thread breakage and bobbin shape were evaluated. The spinning conditions were as follows.

Spinning condition Thread type: 56 dtex-24 filament-core-sheath composite fiber core: sheath = 2: 1
Polymer; Core Polyester (Bright)
Sheath Isophthalic acid 20 mol% copolymerized polyester Spinning method; Spin draw method Spinning temperature; 290 ° C
Spinning speed: 3,600 m / min
Continuous spinning period; 2 days Number of spindles; 8

The yarn characteristics of the obtained core-sheath type composite fiber were as follows.

Yarn characteristics decitex; 54dt
Strength: 4 cN / dt
Elongation: 40%

Application of the mixed oil or the like to the surface of the die was performed as follows.

Example 1 A mixed oil containing dimethyl silicone and methylphenyl silicone was sprayed on the base surface, then rubbed with a brass spatula 10 times, and then the mixed oil was sprayed and applied.
Comparative Example 1 Methylphenyl silicone was sprayed on the surface of the die, and then with a brass spatula, 10
I rubbed.
Comparative Example 2 Methylphenyl silicone was sprayed on the surface of the die, and then with a brass spatula, 10
Then, the oil was sprayed and applied.
Comparative Example 3 A mixed oil containing dimethyl silicone and methylphenyl silicone was sprayed on the surface of the die, then rubbed with a brass spatula 10 times, and then methylphenyl silicone was sprayed and applied.

  The results of Examples and Comparative Examples are as shown in Table 1.

In Example 1, in a spinning period of 2 days, 1 spindle out of 8 spindles was almost free from yarn breakage, and it was good.
The bobbin shape was also good.
In Comparative Example 1, the mouthpiece surface was cleaned with methylphenylsilicone alone, but no dimethylsilicone was contained, the mold release property was inferior, and all spindle threads were broken. In addition, the polymer discharge from the nozzle nozzle became unstable, resulting in many defective shape of the take-up bobbin.
In Comparative Example 2, the base surface was cleaned with methylphenyl silicone, and another layer of methylphenyl silicone was formed. Since the surface of the die was covered with methylphenyl silicone in two layers and the polymer discharge part was kept wet, both the thread breakage and bobbin shape were good compared to Comparative Example 1. However, dimethyl silicone excellent in releasability was not used, and both the thread breakage and bobbin shape were inferior compared to the examples.
In Comparative Example 3, a mixed oil containing dimethyl silicone excellent in releasability was applied to the surface of the die, and methyl phenyl silicone having high heat resistance was applied so as to cover it. There were few thread breaks and the bobbin shape was good, but this method uses two types of release agents,
The work was troublesome and there was a problem in workability.

Claims (2)

When melt-spinning fibers using a thermoplastic resin, a mixed oil containing methylphenyl silicone and dimethylphenyl silicone is applied to the spinneret surface and then a part thereof is removed, and the mixed oil is further applied to the spinneret surface. A method for producing a fiber, characterized in that the fiber is coated on and spun. The fiber to be melt-spun is a composite fiber composed of a polymer having two or more components, and 40% or more of the periphery of the cross-section of the composite fiber is a composite fiber formed of a copolyester having a lower melting point than other components. A method for producing fibers.