JPH0571015A - Split and division type conjugate fiber and production thereof - Google Patents

Abstract

PURPOSE:To produce the subject fiber capable of producing an ultra-fine fiber by splitting it in a division process although the shape of a conjugate fiber is maintained till a certain process of production of a fiber or fabric by conjugate-spinning a polyester and a specified polyamide under a special condition. CONSTITUTION:With (A) 90-30 pts.wt. nylon 6 and/or nylon 66 as a polyamide, (B) 10-70 pts.wt. polyamide (e.g. nylon 8) in which the ratio of methylene groups to amide groups in the main chain of the polymer is 7-11 is blended and melt kneaded and the resultant polyamide is used in combination with a polyester for conjugate-spinning. The conjugate-spinning is carried out while controlling the atmospheric temperature 1-3cm directly under the spinning nozzle to <=220 deg.C. Control of the atmospheric temperature directly under the spinning nozzle to a low temperature is carried out pasbestosy by using a heat-insulator such as asbestos for the purpose of heat insulation of the pack surface except the spinning nozzle and blowing out a cooling air from the downward thereof. In addition, the components (A) and (B) are recommendably blended by using a blender, etc., and subsequently melt kneaded by using an extruder used for the conventional melt spinning.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a splittable splittable conjugate fiber composed of polyester and polyamide and a method for producing the same. More specifically, the present invention relates to a split split type conjugate fiber having improved adhesive strength between two components and a method for producing the same.

[0002]

2. Description of the Related Art Conventionally, a method of arranging two kinds of polymers so as to be separable to form a composite fiber and dividing both components in a post-processing step has been known for a long time. In recent years, a single yarn 0.5 obtained by splitting such peelable splittable conjugate fiber
Ultrafine fibers of denier or less are used as knitted fabrics as long fibers or as short fibers for artificial leather and staples, etc., and show softness of surface and special texture. In the limelight.

The cross-sectional shape of the splittable splittable conjugate fiber is as follows.
In addition to the radial branch type as shown in Japanese Patent Publication No. 48-28505, the annular hollow type as shown in Japanese Patent Publication No. 53-10169, and the adjacent piece type shown in Japanese Patent Laid-Open No. 61-231264. Various cross-sectional shapes are known.
Polyester, polyamide, polystyrene, polypropylene, polyethylene and the like are known as polymers constituting the conjugate fiber. In particular, a combination of polyester and polyamide is often used as a constituent polymer because of the dyeing properties and physical properties of the resulting fabric product and the ease of division.

As a method for separating and separating the composite fiber, a method of swelling or dissolving and removing one component using an organic solvent, a method of decomposing and removing a part with an alkaline aqueous solution, and a method of separating by mechanical force such as jet flow are used. The method of division is used. In particular, the division by jet flow is an excellent method suitable for industrial production, without the problem of environmental pollution, as compared with the method using an organic solvent or an alkaline aqueous solution.

Originally, the greatest advantage of the separation-splitting type composite fiber is that it maintains the form of the composite fiber without separation separation until a certain stage of the fiber manufacturing process or post-processing, and is performed in any subsequent process. It is in the place where it is exfoliated and divided all at once by the dividing treatment to become ultrafine fibers. However, the conventional separation-splittable conjugate fiber is extremely difficult to adjust the adhesiveness of the two components, such as unnecessary splitting in the fiber manufacturing process or difficulty in complete splitting even by splitting treatment.

For this reason, many troubles have occurred in the fiber manufacturing process and the fabric manufacturing process. In particular, a split-split type composite fiber composed of polyester and polyamide, in which nylon 6 or nylon 66 is used as the polyamide, is poor in the mutual adhesiveness of both polymers, and therefore both polymers are used in the fiber manufacturing process or the knitting / weaving process. A part or the whole of the interface of is peeled off, and troubles such as yarn breakage occur.

On the other hand, when the composite fiber is cut into several millimeters to several tens millimeters and dispersed in water to obtain a sheet, a "wet papermaking method" (for example, Japanese Examined Patent Publication No. 56-48628), Both polymers were separated in water before being formed into a sheet, and the ultrafine fibers generated by the division were entangled with each other, resulting in a problem that the resulting sheet often suffers from a granular dispersion defect. Japanese Unexamined Patent Publication No. 47-30903 discloses a proposal to prevent natural exfoliation of composite fibers by adding a non-aqueous oil agent for fibers. However, even in the above proposal, the adhesiveness itself of the two components could not be improved, and when dispersed in water, peeling and division of both components occurred, which had no effect.

Japanese Unexamined Patent Publication (Kokai) No. 1-168819 proposes a method of containing silicone oil to adjust the adhesiveness of both components. However, problems such as deterioration of fiber physical properties and difficulty of dyeing occur, It could not be put to practical use. Further, Japanese Patent Laid-Open No. 3-90619 discloses a proposal in which nylon 6 or nylon 66 copolymerized nylon is used as polyamide, and the mixture is divided with a heated alkaline liquid. But,
Also by this method, peeling division easily occurs in water dispersion,
I couldn't solve the problem.

[0009]

DISCLOSURE OF THE INVENTION The present invention overcomes the above-mentioned drawbacks of the prior art, and allows polyester and polyamide to form a composite fiber without delamination until a certain step of fiber production or fabric production such as knitting, weaving or papermaking. It is an object of the present invention to provide a peelable splittable conjugate fiber which retains its form and undergoes splitting and splitting almost completely by a subsequent splitting process to become an ultrafine fiber.

[0010]

Means for Solving the Problems The present inventors have completed the present invention as a result of intensive studies to solve the above problems. That is, the present invention provides a peelable split type conjugate fiber comprising polyester and polyamide, wherein the polyamide is nylon 6 or / and nylon 66 90.
A composite obtained by mixing 10 to 70 parts by weight of a polyamide having a ratio of the number of methylene groups to the number of amide groups (CH ₂ / NHCO) of 7 to 11 with respect to 30 to 30 parts by weight. It is a fiber.

Further, in the present invention, nylon 6 or / and nylon 6 is used as the polyamide in the production of the splittable splittable conjugate fiber comprising polyester and polyamide.
To 690-30 parts by weight, the ratio of methylene groups and amide groups in the polymer backbone (CH ₂ / NHCO) is 7 to 11
10 to 70 parts by weight of polyamide is mixed and melt-kneaded, and 1 to 3c immediately below the spinneret
m is an atmosphere temperature of 220 ° C. or lower, and spinning is performed.

The peelable splittable conjugate fiber according to the present invention is characterized in that one component comprises a specific polyamide mixture. That is, nylon 6 or / and nylon 66 9
A polyamide containing 0 to 30 parts by weight, and 10 to 70 parts by weight of at least one polyamide having a ratio of the number of methylene groups to the number of amide groups (CH ₂ / NHCO) in the polymer main chain of 7 to 11 is used. To do. Ratio of the number of methylene groups and the number of amide groups in the polymer main chain (CH ₂ / NHC
Examples of the polyamide having O) of 7 to 11 include nylon 8, nylon 610, nylon 612, nylon 1
1, nylon 12, and the like.

In the present invention, nylon 6 or / and nylon 66 and the ratio of the number of methylene groups to the number of amide groups (CH ₂ /
It is necessary that the NHCO) is mixed with a polyamide having a NHCO of 7 to 11 without being copolymerized. The term "mixing" as used in the present invention refers to a state in which the phases are present with substantially independent phases, and is clearly distinguished from copolymerization. When two polyamides have the same ratio of the number of methylene groups and the number of amide groups in the polymer main chain, or the difference between these ratios is less than 2, both polyamides are relatively easily mixed in a molten state and are uniform. It is easy to be in phase. For example, nylon 6 having a ratio of the number of methylene groups to the number of amide groups (CH ₂ / NHCO) of 5 and nylon 66 having the same ratio of 5 are extruded by an extruder which is usually used for melt spinning. Polymerization progresses and the endothermic peak measured by a differential scanning calorimeter (DSC) shows only a single peak.

On the other hand, two types of polyamide having a difference in the ratio of the number of methylene groups to the number of amide groups of 2 or more do not become a copolymer even in a molten state, and both polyamides have substantially independent phases. To do. This mixture shows by DSC two endothermic peaks corresponding to the melting point of each polyamide. In addition, the mixed state of the mixed polyamide of the present invention can be easily observed by a scanning electron microscope if a pretreatment for etching with dilute sulfuric acid is performed. According to this observation, in the composite fiber of the present invention, the polyamide mixture is several μm.
It was confirmed that they have a diameter of ˜several tens of μm and do not lead to fibrillation, but exist as long streaks in the fiber axis direction.

Although the peelable splittable conjugate fiber of the present invention is composed of a combination of polyester and polyamide, which have poor adhesiveness to each other, the reason why the adhesiveness is improved is not clear, but as described above, It is presumed that a polyamide having a large ratio of the number of methylene groups to the number of amide groups is mixed in nylon 6 or / and nylon 66 with an independent phase.

The amount of the polyamide mixed with nylon 6 and / or nylon 66 should be 10 to 70 parts by weight. If it is less than 10 parts by weight, the adhesiveness is not improved. If the mixing amount exceeds 70 parts by weight, the adhesion with the polyester becomes too strong, and the separation and division becomes difficult even by the division treatment. The preferred mixing ratio is 20
˜50 parts by weight.

As the polyester used in the present invention, a normal polyester such as polyethylene terephthalate is used. The polyester and polyamide of the present invention may be blended with additives such as an antistatic agent, a matting agent and a pigment as long as the amount and type are within the range that does not impair the basic physical properties.

The composite cross-section structure of the fiber of the present invention is shown in FIGS.
As illustrated in c, it is necessary that one component continuously exists in the fiber cross section and the other component be divided into a plurality of independent layers. The number of the independent layers is generally 4 to 12, and preferably 4 to 10. The composite ratio of the layers of the two components is about 10 to 50% with respect to the total cross-sectional area of one component, and is preferably about 20 to 40% from the viewpoint of dyeability and texture of the obtained fabric product.

The fineness of the fibers after division is preferably 0.5 denier or less for the single yarn of the independent layer from the viewpoint of feeling and moisture permeability. In particular, it is more preferably 0.05 to 0.2 denier to obtain a suede-like texture.
The separation and division treatment of the fiber of the present invention is a method of swelling or dissolving one component with an organic solvent in the stage of long fiber or staple, or a state of knitted woven fabric or nonwoven fabric, or dissolving a part of the polyester component with an alkaline aqueous solution. A method of removing, a method of separating and separating by a mechanical force such as a jet flow, etc. can be adopted. The effect of the fiber of the present invention is best exhibited in the case of separating and splitting by a jet flow.

The method for producing the splittable splittable conjugate fiber of the present invention will be described below. The production method of the present invention is characterized in that a specific polyamide is mixed as a polyamide component and melt-kneaded is used to specify the atmospheric conditions immediately below the spinneret. That is, in the production of a peelable split type composite fiber composed of polyester and polyamide, as the polyamide, nylon 6 or / and nylon 6690-
Using 10 to 70 parts by weight of a polyamide having a ratio of the number of methylene groups to the number of amide groups (CH ₂ / NHCO) of 7 to 11 to 30 parts by weight and melt-kneading, and It is characterized in that an atmosphere temperature of 1 to 3 cm immediately below the spinneret is 220 ° C. or less and the spinning is performed.

Nylon 6 and / or Nylon 66
And a polyamide having a ratio of the number of methylene groups to the number of amide groups (CH ₂ / NHCO) in the polymer main chain of 7 to 11,
Despite being homologous polyamides, both are incompatible even when melt kneaded. Therefore, when the composite fiber composed of the mixed polyamide and polyester is attempted to be spun by ordinary melt spinning, a so-called "rain-driving" is formed immediately below the spinneret, and normal spinning is difficult.

In the present invention, it has been found that the above "rain precipitation" can be completely eliminated by spinning at an atmosphere temperature of 1 to 3 cm immediately below the spinneret of 220 ° C. or lower. The ambient temperature directly under the spinneret is about 2 for commercial melt spinning.
The feature is that the temperature is extremely low compared to the high temperature of 50 ° C. or higher. The lower the ambient temperature, the more the "rain fraying" is eliminated, but at a temperature of about 150 ° C or lower, the draw ratio at the time of drawing following spinning decreases. Therefore, the preferred ambient temperature is 220 ° C.
~ 150 ° C.

The atmospheric temperature immediately below the spinneret refers to the temperature in the vicinity of 1 to 3 cm below the spinneret and about 1 cm away from the spun yarn. As a method for adjusting the atmosphere temperature directly below the spinneret to a low temperature, a method of directly blowing cooling air on the spinneret surface or a method of cooling the yarn with cooling air from directly below is adopted. More specifically, a method in which the surface of the pack other than the spinneret surface is shielded by a heat insulating material such as asbestos, and cooling air is blown from below is preferable. By combining the thickness of the heat shield with the distance from the spinneret surface from which the cooling air is blown, the ambient temperature specified in the present invention can be set.

The blowing direction of the cooling air may be from one side of the yarn or from the surroundings. The cooling air may have a temperature of 10 to 20 ° C. and a humidity of 50 to 90% RH, which is used for ordinary melt spinning. In the present invention, nylon 6 or / and nylon 66 and the ratio of the number of methylene groups to the number of amide groups in the polymer main chain (CH ₂ / NHC
In the mixing of the polyamide having O) of 7 to 11, the two are weighed in a predetermined ratio at the stage of pelletizing and mixed with a mixer such as a blender or a jet color. Next, they are melt-mixed by an extruder used for ordinary melt spinning. If necessary, a kneading device such as a static kneading element may be used after the extruder.

The melt-kneading temperature and time are preferably 270 to 310 ° C. and 5 to 30 minutes, which are used in ordinary melt spinning. Within this range, the two kinds of polyamides specified in the present invention are present in the fiber as polyamide phases independent of each other with almost no copolymerization. As a method of composite spinning two components of polyester and polyamide with the composite fiber of the present invention, Japanese Patent Publication No. 48-28
It is carried out according to the composite spinning method disclosed in Japanese Patent Publication No. 005 or Japanese Patent Publication No. 53-10169.

When the drawing step following spinning is carried out continuously, it can be carried out according to JP-B-63-53292. Furthermore, in order to omit the stretching step, even in the single-stage spinning method in which the spinning speed is about 5000 m / min or more,
The spinning method of the present invention has remarkable effects.

[0027]

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

[0028]

Example 1 As a polyester component, an intrinsic viscosity [η]
(Orthochlorophenol, measured with 1% solution) 0.6
Polyethylene terephthalate of No. 1 was used, and the relative viscosity ηrel = 2.4 (95% H ₂ S
O ₄ , measured with 1% solution) Nylon 6 (CH ₂ / NHC
O = 5) pellets and nylon 612 (CH ₂ / NHCO = 8) pellets having a relative viscosity ηrel = 2.3 were mixed at the weight ratio shown in Table 1 and used.

45 mm each of the above polymers at 290 ° C.
After being melted using an extruder of φ, L / D = 25, it is subjected to a general separation division type composite spinning device via a gap pump, and a polyester section is radially divided into eight by a polyamide section, and a composite cross-section structure (Fig. 1-a). The composite ratio of polyester and polyamide was 70% polyester and 30% polyamide based on the total cross-sectional area.

On the spinneret surface, the pack surface excluding the discharge surface was covered with an asbestos plate having a thickness of 30 mm, and the yarns 30 mm below the spinneret surface were adjusted to 20 ° C. and the flow rate was 0.2 m.
It cooled with the cooling air of / s. 1 directly below the spinneret at this time
The ambient temperature in the vicinity of the filament of cm was 200 ° C. The spinning conditions were all good.

The spun yarn was oiled by a usual method and then wound at 1500 m / min. Then hot plate temperature 140
It was drawn 2.70 times at 0 ° C. to obtain a composite fiber of 75 d / 50 f (single yarn before splitting 1.5 d / f). The obtained composite fiber is cut into 10 mm long fibers to obtain short fibers.
No. 628 Publication A non-woven sheet was produced according to Example 1C.

The evaluation of the separation division of the composite fibers in the papermaking slurry in which the short fibers were dispersed was judged by the number of defects of defective particle dispersion per 1 m ² of the sheet after the slurry was made. That is, in the case where peeling and division did not occur in the papermaking slurry, there was no defect of this granular dispersion failure. In the evaluation of separation by jet flow, a high-speed water stream was made to impinge on the sheet at a pressure of 25 kg / cm ² from an injection nozzle, and then the air passage pressure loss of the sheet was measured. From the relationship between the average single yarn denier and the air passage pressure loss of the sheet obtained in advance, the average single yarn denier (Do) of the sheet after the separation division is performed.
I asked.

The division ratio was calculated by the following equation.

[0034]

[Equation 1]

However, Dc is the average single yarn denier after division calculated on the assumption that 100% division is performed. In this example,

[0036]

[Equation 2]

It is As is clear from Table 1, when the weight part of the nylon 612 is 10 to 70, it has preferable process performance that the division during the papermaking is suppressed and then it is completely divided by the jet flow. I understand.

[0038]

[Table 1]

[0039]

Comparative Example In Example 1, a copolyamide of nylon 6 and nylon 612 was used as the polyamide component. The copolymerization ratio is nylon 6 / nylon 612 = 70 /
30 parts by weight (corresponding to No. 5 of Example 1) and 30/7
According to Example 1, a papermaking test was conducted using two kinds of 0 parts by weight (corresponding to No. 7 of Example 1).

Table 2 shows the dispersibility at the time of papermaking and the division ratio of the jet flow treatment.

[0041]

[Table 2]

As is apparent from this comparative example, when the copolyamide was used as the polyamide component, the adhesiveness with the polyester component was lowered, and the division easily occurred during the papermaking.

[0043]

Example 2 In Example 1, as the polyamide to be used, 70 parts by weight of nylon 66 and 30 parts by weight of each of the various polyamides shown in Table 2 were used, and a composite fiber was obtained in the same manner as in Example 1. In order to determine the mixed state of two polyamides in the polyamide component, the composite fiber was treated with 10% NaOH.
The polyester component was completely dissolved and removed by treating with an aqueous solution at 40 ° C. for 3 days and nights. The melting temperature of the remaining polyamide fiber was measured by DSC. Table 3 shows the peak temperatures measured by DSC.

In addition, Table 3 shows the peeling-dividability when the composite fiber was produced in the same manner as in Example 1 to produce a nonwoven fabric sheet. Table 3
As is clear from the above, the composite fiber made of the polyamide in which the polyamide in which the ratio of the number of methylene groups to the number of amide groups is 7 to 11 was mixed had good process performance.

[0045]

[Table 3]

[0046]

[Example 3] In the same manner as in Example 1, 70 parts by weight of nylon 6 and 30 parts by weight of nylon 612 were spun in the same manner as the polyamide component. At the time of spinning, the thickness of the asbestos heat shield covering the spinneret surface and the cooling air blowing position were variously changed, and the atmospheric temperature of 1 cm immediately below the spinneret was changed.
The same procedure as in Example 1 was performed except that the settings were made as shown in FIG.

Table 4 shows the presence / absence of occurrence of "rain fraying" during spinning, and the number of yarn breakages per 10 ⁶ m when the undrawn yarn which has been wound is drawn. Industrial spinning / drawing is possible within 1/10 ⁶ m. As is clear from Table 4, the mixed polyamide was satisfactorily spun by setting the atmospheric temperature of 1 to 3 cm immediately below the spinneret to 220 ° C. or lower.

[0048]

[Table 4]

[0049]

Industrial Applicability According to the present invention, it is possible to produce a split-split type composite fiber made of polyamide in which polyester and a specific polyamide are mixed. The obtained conjugate fiber, by adjusting the adhesiveness of polyester and polyamide, can be carried out without causing separation and separation until the fiber production stage or the knitting or weaving of the cloth, or the necessary stage of the nonwoven fabric production process. The feature is that the two components can be completely divided by the division processing of.

The composite fiber of the present invention makes use of this characteristic,
By forming a knitted woven fabric as long fibers and then subjecting the knitted woven fabric to division treatment to obtain an ultrafine fiber fabric, moisture permeability and waterproofness and a soft texture can be obtained. Also, after applying the crimp, it is cut into several cm to several tens of cm and used as a staple to obtain a spal-like ultrafine fiber cloth having an extremely high-grade feeling. Of course, cotton, wool,
It is also possible to blend natural fibers such as hemp and acrylics.

Furthermore, when the composite fiber of the present invention is cut into a few mm to a few tens of mm and used as an artificial leather, an artificial leather having an excellent leather-like texture can be obtained.

[Brief description of drawings]

FIG. 1 is a fiber cross-sectional view schematically illustrating a composite structure of a fiber cross-section of a composite fiber according to the present invention.

Claims (2)

[Claims] 1. A peelable splittable conjugate fiber comprising polyester and polyamide, wherein the polyamide is 90 to 30 parts by weight of nylon 6 or / and nylon 66 and the ratio of the number of methylene groups to the number of amide groups in the polymer main chain (CH ₂
/ NHCO) 7 to 11 and polyamide 10 to 70
A composite fiber, which is a polyamide mixed with parts by weight. 2. A nylon 6 or / and a nylon 6690-30 is used as the polyamide in the production of a peelable splittable conjugate fiber composed of polyester and polyamide.
Using 10 to 70 parts by weight of polyamide having a ratio of the number of methylene groups to the number of amide groups (CH ₂ / NHCO) in the polymer main chain of 7 to 11 to parts by weight and melt-kneading, and a spinneret A method for producing a composite fiber, which comprises spinning at an atmosphere temperature of 1 to 3 cm immediately below 220 ° C. or less.