JPH03234817A - Conjugate yarn of readily dyeable high-strength polyester - Google Patents

Abstract

PURPOSE:To obtain the title high strength yarn having a sheath component ratio of specific value and single yarn strength of specific value, dyeable with base dye under pressure, comprising a core component made of PET-based polyester and a sheath component composed of a polyester having a metal sulfonate group-containing unit. CONSTITUTION:The objective yarn which is a conjugate yarn comprising a core component A composed of a polyester made of substantially polyethylene terephthalate and having >=0.6, preferably >=0.75 intrinsic viscosity [eta] and a sheath component composed of a polyester having 2.0-8.0mol%, preferably 2.0-3.0mol% metal sulfonate group-containing structural unit, a ratio B/(A+B) of an area of sheath component B to the section of the yarn of 0.2-0.75, preferably 0.35-0.55 and >=5.5g/d strength of single yarn.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention has high strength and can be dyed with basic dyes under normal pressure, and is suitable for use in synthetic resins such as polyurethane and soft polyvinyl chloride, synthetic paints, Industrial materials and lifestyle-related textile products that have little dye transfer even when used in combination with (in contact with) rubber (e.g. sports clothing, breathable waterproof fabrics, sports tents, tarpaulins, tents, raincoats, car body covers, shoes, bags) It relates to polyester fibers used for fabrics such as fabrics, fabrics, sewing threads, etc.

[Prior Art] Conventionally, polyester fibers, mainly made of polyethylene terephthalate, have been used in a variety of fields due to their good physical and chemical properties, and are widely used as one of the most useful synthetic fibers. has been done.

However, in terms of dyeability, it is inferior to other synthetic fibers and natural fibers, and it has been necessary to use high-pressure dyeing or carrier dyeing, but the former requires the use of high-pressure dyeing equipment and increased utility. There were nine problems: an increase in costs due to the use of polyester fibers, and a decrease in the performance of the polyester fiber itself, and for the latter, it was necessary to take measures to prevent pollution caused by carrier substances. Moreover, only disperse dyes can be used as dyes to dye polyester fibers.
If twisted yarn or knitted fabric made of polyester fiber is processed or used in combination with, in contact with, soft polyvinyl chloride, synthetic resin such as urethane resin, rubber made of natural rubber or synthetic rubber, or synthetic paint, processing is prohibited. There are problems with sublimation of dyes due to temperature, migration of dyes into synthetic resins or rubber, and migration of dyes into synthetic resins or synthetic paints over time during product use. That was impossible. Furthermore, dyed products using disperse dyes have the problem that it is difficult to obtain clear colors.

As a measure to improve these drawbacks, it has been proposed to use fibers made from copolymerized polyester (Japanese Patent Publication No. 10497/1983). A typical example is polyethylene terephthalate copolymerized with an isophthalic acid component containing a metal sulfonate group.
The most useful copolymerization component is 5-sodium sulfoisophthalate.

However, in order to obtain fibers that can be dyed with basic dyes under normal pressure by this method, the copolymerization component 5-sodium sulfoisophthalic acid must be added at 3.0 mol% of the total acid component.
However, since the melt viscosity of polyethylene terephthalate copolymerized with pentasodium sulfoisophthalate significantly increases, melt spinning cannot be performed unless the degree of polymerization of the raw material polymer is lowered. , and 5 more
Coupled with the increase in intermolecular force of sodium sulfoisophthalate, the drawability becomes poor, so the draw ratio must be significantly lowered compared to polyethylene terephthalate, and the strength of the resulting fiber is only 3 g/ It was about d.

In order to solve these problems, the core component is polyamide,
A patent has been filed for a composite fiber using melt-spun polymers such as polyethylene terephthalate and polybutylene terephthalate, and using polyethylene terephthalate copolymerized with 3 to 6 mol% of 5-sodium sulfoisophthalate as a sheath component. (For example, JP-A-59-3091
2), the strength of the fiber obtained by this method is 5 g/d or less, and although the strength is satisfactory for clothing fibers, it does not have the strength required for fibers for industrial materials and daily life-related materials. was not satisfactory.

Furthermore, no direction or method for obtaining high-strength, easily dyeable polyester composite fibers has been proposed until now.

[Problem to be solved by the invention] Living-related materials and industrial materials are basically required to have high strength (tensile strength, tear strength), and it is desirable for them to be lightweight in terms of handling and cost. . If the fibers used for these purposes have a yarn strength of less than 5.5 g/d, product design becomes difficult, and ordinary polyester fibers are difficult to use. In order to increase the degree of freedom in the design of textile products, and to take into account ease of handling and cost, a yarn strength of 5.5 g/d or more, preferably 6.0 g/d or more is required.

An object of the present invention is to provide polyester fibers that have high strength and can be dyed with basic dyes under normal pressure.

The object of the present invention is to provide polyester fibers suitable for use in composites with or in contact with rubbers, synthetic resins, and synthetic paints among industrial materials and life-related materials that require particularly high strength.

[Means for Solving the Problems] The present invention is a polyester in which the core component A is substantially composed of polyethylene terephthalate and has an intrinsic viscosity [η] of 0.6 or higher, and the sheath component B is a polyester containing a metal sulfonate group-containing structural unit. The composite fiber is a polyester having 0 to 8.0 mol%, the area ratio B/(A+B) of the sheath component B in the cross section of the fiber is 0.2 to 0.75, and the single fiber strength is It is a composite fiber characterized by having a fiber density of 5.5 g/d or more.

The polymer constituting the core component of the easily dyeable high-strength polyester conjugate fiber according to the present invention consists essentially of polyethylene terephthalate. "Substantially" means that 90% or more of the core component is polyethylene terephthalate;
If necessary, copolymerize dibasic acid or nol,
Although it is possible to blend other polymers, 10
If the modification or blending exceeds %, the yarn strength will be insufficient.

Intrinsic viscosity of polyester that constitutes the core component of composite fiber [
η] must be 0.6 or more. If we consider only the strength of single fibers, it is possible to obtain composite fibers with a strength of 5.5 g/d or more even if the intrinsic viscosity is less than 0.6.However, as mentioned above, the composite fibers according to the present invention can be used for household goods, industrial products, etc. It is intended to be used as a material, and if the intrinsic viscosity is less than 0.6, resistance to bending, abrasion, etc. is poor, and durability is insufficient. It is more preferable that the intrinsic viscosity [η] is 075 or more.

The main component of the polyester having a metal sulfonate group-containing structural unit constituting the sheath component is polyethylene terephthalate or polybutylene terephthalate, and 20 mol% to 8.0% of the acid component constituting the polyester.
% by mole is modified with a dibasic acid having a metal sulfonate group or a derivative thereof.

Examples of dibasic acids having metal sulfonate groups or derivatives thereof include 5-sodium sulfoisophthalate, dimethyl(5-sodium sulfo)isophthalate, his-
2-hydroquinoethyl (5-sodium sulfo) isophthalate, bis-4 hydroquinobutyl (5-sodium sulfo) isophthalate, and the like. Dimethyl (5-sodium sulfo) isophthalate is preferred.

If the degree of modification by the dibasic acid or its derivative is less than 2 mol %, dyeability under normal pressure cannot be obtained.

If the degree of modification exceeds 8.0 mol%, the dyeability will be very good, but the melt viscosity of the polymer will increase rapidly, and the sheath component will be discharged unevenly during spinning of composite fibers, making it difficult to form a uniform set. As a result, uniform staining cannot be obtained. A preferred degree of modification is 20 to 60 mol%, more preferably 20 to 3.0 mol%. The main component of the sheath, polyethylene terephthalate or polybutylene terephthalate, contains HO(CH-) as a diol component.
It is also possible to copolymerize 20 mol% or less of OH (n is 2 to 6). It may also contain 10% by weight or less of polyalkylene oxide.

It is also possible to copolymerize up to 2.0 mol % of a component having no metal sulfonate group (for example, phthalic acid, isophthalic acid, etc.) as the dibasic acid or its derivative component.

The intrinsic viscosity [η] of the raw material polymer constituting the sheath component is 0.
40-060 is preferable, and 0845-055 is more preferable.

The sheath component of the composite fiber according to the present invention should have an area structure/(core+sheath) of 02 to 075 in a single fiber.

If the area ratio is smaller than 0.2, a dark color will not be obtained.
, if it exceeds 0.75, the strength is insufficient. Preferably, the area ratio is 03 to 0.6, more preferably 035 to 0.5.
It is 5.

The sheath component of the composite fiber according to the invention must be combined with the core component to cover the entire surface of the single fiber. In order to obtain uniform color development after dyeing, it is more preferable that the core component and the sheath component are combined concentrically, or they may be combined eccentrically. The cross-sectional shape of the single fiber is not limited to a circle, and irregular cross-sections such as an ellipse, Y-shape, T-shape, X-shape, Δ-shape, polygon, etc., and hollow cross-sections can also be adopted.

FIG. 1 shows the relationship between the single fiber strength of easily dyeable polyester fiber and the intrinsic viscosity [η] of the core component polyethylene terephthalate. Line segment A uses polyethylene terephthalate copolymerized with 2.0 mol% of dimethyl (5-sodium sulfo) isophthalate as the sheath component, and the cross-sectional area ratio of the sheath component is set to 0.
2, line segment B uses polyethylene terephthalate copolymerized with 8.0 mol% dimethyl (5-sodium sulfo) isophthalate as the sheath component, and the cross-sectional area ratio of the sheath component is 02. In the case, line segment C is obtained when polyethylene terephthalate copolymerized with 20 mol % of dimethyl (5-sodium sulfo)isophthalate is used as the sheath component, and the cross-sectional area ratio of the sheath component is set to 0.75. The line segment X has a single fiber strength of 5.5 g/d, and the line segment Y has the same e.
, og/d, and the line segment Z shows that the intrinsic viscosity [η] is 0.8. The easily dyeable polyester composite fiber of the present invention is the fiber in the shaded area in FIG.

The easily dyeable high-strength polyester composite fiber of the present invention can only be achieved by satisfying all of the following manufacturing techniques.

■In order to set the intrinsic viscosity [η] of the core component constituting the single fiber to 0.6 or more, preferably 075 or more, the intrinsic viscosity [η] of the raw material polymer of core component = IQ is 065 or more, preferably 0.82 The above shall apply.

(2) The intrinsic viscosity of the sheath component polymer [η] should be 04 to 0.6, preferably 045 to 0.55.

■In order to make the spun yarn highly stretchable, the wet heat shrinkage rate of the spun yarn (heated for 5 minutes under a -g00/d load in saturated steam at 100°C) is 60% or less, and the to have a refractive index of 5×10−3 or less;
As a measure for this purpose, low speed spinning of 1000 m/min or less is preferable.

(2) Stretching the above-mentioned spun yarn by 3.5 times or more, which is not used for ordinary polyester fibers.

The characteristic of the composite fiber of the present invention is that by adopting the manufacturing conditions as described above, a small amount (particularly 3 mol% or less) of metal sulfonate-modified polyester, which has been considered to have poor dyeability under normal pressure, is removed from the sheath. Even when used as a component, sufficient dyeability can be obtained. Although the reason for this is not clear, it is thought that the adoption of a high stretching ratio among the above-mentioned manufacturing techniques greatly promotes this.

The composite fiber according to the present invention has high strength, an elongation at break of 40% or less, and a hot water shrinkage rate of 5% in water at 100°C.
Below, if the dry heat shrinkage rate in hot air at 200°C is 20% or less, it is suitable for composites by laminating, coating, dipping, etc. with synthetic resins, and is suitable for use in sports clothing, sports tents, breathable waterproof fabrics, tarpaulins, etc. Kuji,
Suitable for use in bags, tents, raincoats, car body covers, umbrellas, etc.

Furthermore, if the cutting elongation is 30% or less, the hot water shrinkage rate in 100°C water is 3% or less, and the dry heat shrinkage rate in 200°C hot air is 15% or less, it can be used for sewing thread (for materials, It can be applied to industrial, household, etc.

The easily dyeable high-strength polyester composite fiber referred to in the present invention can be produced in the form of filament yarn, tow, or stable. Filament yarns are used as they are or processed yarns to make twisted yarns, woven or knitted fabrics, stable yarns are used as spun yarns to make twisted yarns, woven or knitted fabrics, or nonwoven fabrics, and tows are used as spun yarns to make twisted yarns, woven or knitted fabrics, or tow-like nonwoven fabrics.

Although there is no single fiber denier limit for the easily dyeable high-strength polyester composite fiber according to the present invention, considering industrial productivity,
, (ldr-20dr is preferred, 1.5dr-1
5dr is more preferable. Yarn denier of 50 dr to 1500 dr is suitable as the filament yarn.

A matting agent, a flame retardant, a pigment, a hydrophilic agent, a filler, etc. can be appropriately mixed into the core component and sheath component of the polyester composite fiber, if necessary.

In the present invention, the intrinsic viscosity [η] is a value obtained by dissolving a polyester compound in a solvent of phenol/tetrachlorethylene at a ratio of 1/1 (weight ratio) and measuring the viscosity at 30'C.

The intrinsic viscosity of the core component of the single fibers constituting the yarn is determined by completely dissolving only the sheath component with 5% caustic soda at 100°C, leaving only the core component undissolved, and measuring it by the method described above after piloting.

In the present invention, strength and elongation were measured according to JISL-1013.

The birefringence (Δn) in the present invention is determined by a conventional method from retardation observed under polarized light using an optical microscope. (For a detailed explanation of this method, please refer to Kyoritsu Publishing's "Polymer Experimental Course Physical Properties of Polymers ■") Using polyethylene terephthalate copolymerized with 2.5 mol% of dimethyl (5-sodium sulfo) isophthalate as a component, the spinning speed was 800 m/mi so that the cross-sectional area ratio of the sheath component was as shown in Table 1.
Melt spinning was performed at n to obtain spun fibers of composite fibers. The birefringence of all of these spun yarns is 3.0 to 3. sx 1o-
3, and the wet heat shrinkage rate in saturated steam at 100°C is 5.
It was 5-58%.

These spun yarns were stretched 3.85 times at a stretching temperature of 80°C, and heat-set with a hot roller at 210°C to a length of 250 d.
/48f composite fiber filament yarn was obtained. Table 1 shows the performance of composite fibers obtained by varying the cross-sectional area ratio of the sheath component. When the cross-sectional area ratio of the sheath component was less than 0.2, the dyeability was insufficient, and when it was greater than 0.75, the strength was insufficient.

3 14 ~ Prototype Example 2 Polyethylene using polyethylene terephthalate with an intrinsic viscosity [η] of 0.96 as the core component and changing the copolymerization ratio of dimethyl (5-sodium sulfo) isophthalate as shown in Table 2 as the sheath component. Using terephthalate, the spinning speed was 80 so that the sheath component cross-sectional area ratio was 0.5.
Melt spinning was performed at 0 m/min to obtain spun yarn of composite fiber. The birefringence of all these spinning yarns is 30 to 4.5X
It was 10-3. Further, the shrinkage rate in saturated steam at 100°C was 53 to 59%. Using these spun yarns, stretching was carried out in the same manner as in Prototype Example 1 to a length of 250 d/48
A filament yarn of f was obtained. The performance of the obtained composite fiber is as shown in Table 2, and the sheath component contains dimethyl (5-
Those using polyethylene terephthalate copolymerized with 10 mol % of sodium sulfo)isophthalate lacked strength and had uneven dyeing, making them impractical.

Prototype Example 3 Polyethylene terephthalate with an intrinsic viscosity [η] of 0.75 was used as the core component, and polyethylene terephthalate copolymerized with 2.5 mol% of dimethyl (5-sodium sulfo) isophthalate was used as the sheath component. The spinning speed was set at 800 m/m to achieve the cross-sectional area ratio of the sheath components shown in Table 3.
Melt spinning was performed at min. to obtain a spun yarn of composite fiber.

The birefringence of all of these spun yarns is 3.5 to 4. OX1
0-3, and the shrinkage rate in 100℃ saturated steam is 5
The percentage ranged from 2 to 56%. These spun yarns were drawn at a temperature of 80
The filament yarn was drawn 3.7 times at ℃ and heat-set using a hot roller at 1850C to obtain a filament yarn of 150d/48f. The performance of the obtained composite fibers is shown in Table 3.

(Margin below) =15 6 7

[Brief explanation of drawings]

FIG. 1 shows the relationship between the single fiber strength of easily dyeable polyester fiber and the intrinsic viscosity [η] of the core component polyethylene terephthalate. Line segment A is when polyethylene terephthalate copolymerized with 2.0 mol% of tsumedel (5-sodium sulfo) isophthalate is used as the sheath component, and the cross-sectional area ratio of the sheath component is 02, and line segment B is Dimethyl (5-sodium sulfo) isophthalate in the sheath component
When using 0 mol% copolymerized polyethylene terephthalate and setting the cross-sectional area ratio of the sheath component to 0.2, line segment C
In this example, polyethylene terephthalate copolymerized with 2.0 mol % of dimethyl (5-sodium sulfo)isophthalate was used as the sheath component, and the cross-sectional area ratio of the sheath component was set to 0.75. Line segment X shows a single fiber strength of 5.5 g/d, line segment Y shows the same 6.0 g/g, and line segment Z shows an intrinsic viscosity [η] of 0.6.

Claims (1)

[Claims] The core component A is a polyester consisting essentially of polyethylene terephthalate and has an intrinsic viscosity [η] of 0.6 or more, and the sheath component B is a polyester having a metal sulfonate group-containing structural unit.
A conjugate fiber which is a polyester having 0 to 8.0 mol%, the area ratio of the sheath component B to the cross section of the fiber B/
(A+B) is 0.2 to 0.75, and the single fiber strength is 5
．． A composite fiber characterized by having a weight of 5 g/d or more.