JP5819620B2 - Polyester microfiber - Google Patents

Description

  The present invention relates to a polyester microfiber having high strength and excellent dimensional stability.

  Conventionally, ultrafine fibers have been used in industrial materials such as clothing fabrics, artificial leather, and filters in order to exhibit flexibility, aesthetics, and denseness. As materials for ultrafine fibers, polyamides such as nylon 6 and nylon 66 and polyesters such as polyethylene terephthalate are generally used. However, the ultrafine fiber made of polyamide has a problem that the weather resistance such as yellowing is poor due to the inherent property of this material, and its application is limited. On the other hand, the ultrafine fiber made of polyester has a problem that it has excellent weather resistance but lacks flexibility and flexibility.

  Therefore, in order to increase flexibility, it is necessary to further reduce the fineness. However, as a method for producing a polyester ultrafine fiber, Patent Document 1 (W02005 / 095686) has 100 islands or more per filament. It has been proposed to remove a sea component from a sea-island composite fiber to obtain a flexible and supple ultra-fine polyester fiber. Certainly, this method can provide polyester ultrafine fibers with practical strength and flexibility, but the strength and thermal dimensional stability are still unsatisfactory for use in industrial materials. It was sought after.

W02005 / 095686

  An object of the present invention is to provide a polyester ultrafine fiber that is flexible, suitable for industrial materials, and has high strength and excellent thermal dimensional stability.

The inventors of the present invention have arrived at the present invention as a result of investigations to solve the above problems.
That is, according to the present invention,
It consists of polyethylene naphthalate, its single yarn fiber diameter is 10 to 1000 nm, single fiber diameter variation (CV%) is 0 to 12%, tensile strength is 4.0 cN / dtex or more as an ultrafine fiber bundle, elongation at break 10 to 80%, a polyester ultrafine fiber characterized in that the dry heat shrinkage at 150 ° C. is 5% or less,
A textile product comprising the polyester microfiber,
as well as,
Polyethylene naphthalate is used as the island component polymer, the sea component polymer is more soluble than the island component polymer, and the melt viscosity ratio (sea / island) to the island component polymer is 0.
. After melt spinning the sea-island type composite fiber at a take-up speed of 1000 to 3000 m / min using an easily soluble polymer in the range of 8 to 2.0, it is preheated on a preheating roller at 100 to 150 ° C. The polyester ultrafine fiber, wherein the sea component of the sea-island composite fiber stretched at a draw ratio of 1.1 to 6.0 times and subsequently heat-set at 120 to 250 ° C. as the yarn temperature is removed.
Is provided.

  The polyester microfiber of the present invention has a single yarn diameter of 10 to 1000 nm, and is excellent in texture such as touch and softness, and functionality such as friction, adsorptivity, water absorption, permeability, and wind resistance. It becomes a very fine fiber structure. In addition, since the tensile strength is 4.0 cN / dtex or more, it can be used in fields requiring mechanical strength such as industrial applications. Furthermore, when the dry heat shrinkage at 150 ° C. is 5% or less, the dimensional stability is improved. Further, by using ultrafine fibers whose main component is ultrafine fibers, polyethylene naphthalate, high modulus and high strength are obtained, and heat resistance, chemical resistance, and vibration resistance are improved.

Hereinafter, the polyester microfiber of the present invention will be described in detail.
The polyester ultrafine fiber of the present invention is an ultrafine fiber (bundle) made of island component polyester obtained by dissolving and removing the sea component of the sea-island composite fiber.

  The single yarn fiber diameter of the polyester ultrafine fiber of the present invention is 10 to 1000 nm. If the single fiber diameter is less than 10 nm, the fiber structure itself is unstable and the physical properties and fiber form become unstable, which is not preferable. On the other hand, if it exceeds 1000 nm, the softness and texture peculiar to ultrafine fibers are obtained. It is not preferable. The single yarn fiber diameter is determined by the diameter of each island component in the cross section of the sea-island composite fiber, but the higher the uniformity of the diameter, the higher the quality and durability of the high multifilament yarn made of polyester ultrafine fibers.

Further, the CV% value representing the variation in the fineness of the single yarn fibers constituting the polyester microfiber bundle of the present invention needs to be 0 to 12 % . It CV value of this is low, it means that the variation of the fineness is small. Here, by setting the melt viscosity ratio of the sea-island component to 0.8 to 2.5, CV% can be set in the above range.

  The polyester ultrafine fiber of the present invention has a nano-level fiber diameter with little variation, and allows a product design that matches the application. For example, in the filter application, if a substance that can be adsorbed in the single yarn fiber diameter is selected, the fiber diameter can be designed according to the application, and the product can be designed very efficiently. Become.

  The tensile strength as a fiber bundle of the polyester microfiber of the present invention is 4.0 cN / dtex or more, and the cut elongation is required to be 10 to 80%. It is important that the physical properties of the ultrafine fiber, particularly the tensile strength, is 4.0 cN / dtex or more. If the tensile strength is less than 4.0 cN / dtex, the application is limited. It is ultra-fine and flexible, and it can be applied to various applications due to its high strength.

Dry heat shrinkage rate at 0.99 ° C. polyester ultrafine fiber of the present invention should be 5% or less. When the dry heat shrinkage rate at 150 ° C. of the polyester microfiber exceeds 5%, the thermal dimensional stability is poor and the use is limited.

The manufacturing method of the polyester extra fine fiber of this invention is explained in full detail.
The sea component polymer of the sea-island type composite fiber can be appropriately selected as long as it is a combination having higher solubility than the island component polymer, but the dissolution rate ratio (sea / island) is particularly preferably 200 or more. When this dissolution rate ratio is less than 200, part of the island component of the fiber cross-section surface layer is dissolved while the sea component of the fiber cross-section center is dissolved, so the sea component is completely dissolved and removed. In order to do so, the island component will be reduced by a percentage, resulting in deterioration of the strength due to unevenness of the thickness of the island component and solvent erosion, resulting in fluff and pilling, etc. is there.

Next, the greater the number of island components, the higher the productivity when producing ultrafine fibers by dissolving and removing sea components, and the resulting ultrafine fibers are also significantly thinner, with the softness and smoothness unique to ultrafine fibers. In addition, since glossiness and the like can be expressed, it is important that the number of island components is 100 or more, and preferably 500 or more. Here, when the number of island components is less than 100, high multifilament yarns composed of ultrafine fibers cannot be obtained even if sea components are dissolved and removed, and the object of the present invention cannot be achieved. If the number of island components is too large, not only the manufacturing cost of the spinneret increases, but also the processing accuracy of the spinneret itself tends to decrease. Therefore, the number of island components is preferably 1000 or less.

As the easily soluble polymer for sea components at that time, polylactic acid, ultrahigh molecular weight polyalkylene oxide condensation polymer, polyethylene glycol compound copolymer polyester, and
It is preferable to contain at least one alkaline aqueous solution-soluble polymer selected from copolymerized polyesters of polyethylene glycol compounds and 5-monosodium sulfoisophthalic acid.

In the sea-island composite fiber of the present invention, the polyester copolymer of the polyethylene glycol compound and 5-sodium sulfoisophthalic acid is composed of 6 to 12 mol% of 5 monosodium sulfonic acid and 3 to 10 wt% of a molecular weight of 4000 to 400. It is preferably selected from polyethylene terephthalate copolymer in which 12000 polyethylene glycol is copolymerized.

Meanwhile, the island component polymer is preferably Po triethylene naphthalate rate. Examples of polyethylene naphthalate include polyethylene-2,6 synthesized by polycondensation of naphthalene-2,6-dicarboxylic acid or an ester-forming derivative thereof with ethylene glycol in the presence of a catalyst under appropriate reaction conditions. -Naphthalate is mentioned. Furthermore, it is preferable that at least 90 mol% of all repeating units are formed from polyethylene naphthalate (hereinafter referred to as PEN) in which ethylene-2,6-naphthalate units are formed, and at least 95 mol% is ethylene-2,6- Most preferred are naphthalate units. Further, the third component may be copolymerized within a range that does not impair the object of the present invention, for example, within a range of 10 mol% or less, more preferably 5 mol% or less based on the total acid component. Examples of the copolymer component preferably used include, for example, isophthalic acid, diphenyldicarboxylic acid, diphenoxyethanedicarboxylic acid, β-hydroxyethoxybenzoic acid, p-oxybenzoic acid, adipic acid, sebacic acid, 1,4-acid as the acid component. Examples of the diol component include ethylene glycol, propylene glycol, tetramethylene glycol, cyclohexane-1,4-dimethanol, neopentyl glycol, bisphenol A, and bisphenol S. Further, the polyethylene naphthalate may contain a small amount of other polymers, antioxidants, antistatic agents, pigments, fluorescent brighteners and other additives.

  The polyethylene naphthalate preferably has an intrinsic viscosity [η] of 0.45 to 1.0. Here, the intrinsic viscosity [η] is a value obtained from a viscosity measured at 35 ° C. by dissolving the polymer in a mixed solvent of phenol and orthodichlorobenzene (mixing ratio 6: 4). When the intrinsic viscosity [η] exceeds 1.0, the melt viscosity becomes abnormally high and melt spinning becomes difficult, and when [η] is less than 0.45, a fiber having a desired high melting point and good physical properties is obtained. Since it cannot be obtained, it is not preferable.

The sea-island type composite fiber composed of the sea component polymer and the island component polymer needs to have a polymer melt viscosity ratio (sea / island) in the range of 0.8 to 2.0. If it is less than 0.8 times, if the composite mass ratio of the sea component is low, such as less than 50%, the island components are likely to join each other during melt spinning, whereas if it exceeds 2.0 times The stability of the spinning process tends to decrease because the viscosity difference is too large.

  Furthermore, the sea-island composite fiber preferably has a composite mass ratio of sea components of less than 50%. The sea-island composite mass ratio (sea: island) is preferably in the range of 30:70 to 5:95. If it exists in the said range, the thickness of the sea component between island components can be made thin, the dissolution removal of a sea component will become easy, and the conversion to an ultrafine fiber of an island component will become easy. Here, when the proportion of the sea component exceeds 50%, the thickness of the sea component becomes too thick. On the other hand, when the proportion is less than 5%, the amount of the sea component becomes too small and the mutual connection occurs between the islands. It becomes easy.

The sea component and the island component are melted separately, combined into a sea-island shape in the base, and discharged. Thereafter, those were allowed to solidify, such as by cooling air, Ru Hikito as undrawn yarn at 1 000~3000m / min.

The obtained unstretched yarn is stretched by either a winding method after winding once or after winding through a stretching step without winding. The drawing temperature is 100-150 ° C, preferably 110 ° C-130 ° C, preheated on a preheating roller, drawn at a draw ratio of 1.1-6.0 times, preferably 1.2-5.0 times, yarn temperature It is preferable to carry out heat setting at 120 to 250 ° C, preferably 180 to 220 ° C. If it is a slit type heater, 200-250 degreeC is used preferably. In the case where the preheating temperature is insufficient, the intended high-strength drawing cannot be achieved, and if the set temperature is too low, the shrinkage rate of the drawn yarn obtained is too high, which is not preferable. On the other hand, if the set temperature is too high, the properties of the drawn yarn obtained are significantly lowered, which is not preferable.

In order to remove the sea component, it is preferable to treat with an aqueous solution of an alkali metal compound such as sodium hydroxide, potassium hydroxide, sodium carbonate or potassium carbonate, among which sodium hydroxide and potassium hydroxide are particularly preferably used. The concentration, treatment temperature, and treatment time of the alkaline aqueous solution vary depending on the type of alkali compound used, but the concentration is 10 to 300.
g / L, the temperature is preferably 40 ° C. to 180 ° C., and the treatment time is preferably 2 minutes to 20 hours.

  In general, it is preferable to use an aqueous alkali metal compound solution after forming a fiber structure such as a spun yarn or a nonwoven fabric as a knitted fabric or short fiber containing a sea-island type composite fiber. It can process using a well-known alkali weight reduction apparatus.

  The fiber structure consisting of island components after the removal of the sea component is an ultra-fine polyester fiber structure, which is used for environmental and industrial materials such as filters, harmful substance removal products, battery separators, and car interiors such as car seats. Products such as cosmetics, carpets, sofas, curtains and other interior products, cosmetics, cosmetic masks, wiping cloths, health products, etc. and medical uses such as abrasive cloths, sutures, scaffolds, artificial blood vessels, blood filters, and jackets, skirts Used for clothing such as pants and underwear, sports clothing and clothing materials.

The invention is illustrated in more detail by the following examples.
In the following examples and comparative examples, the following measurements and evaluations were performed.

(1) Average single yarn fiber diameter The fiber diameter was calculated | required by TEM observation 30000 times the fine fiber after sea component dissolution removal. Here, the fiber diameter of the single yarn that was not glued was measured. In the fiber diameter data of 100 randomly selected fine fibers, the average single yarn fiber diameter r was calculated.

(2) Average single fiber diameter variation CV%
When determining the average single yarn fiber diameter, the standard deviation σ was calculated, and the fiber diameter variation coefficient CV% defined below was calculated.
CV% = standard deviation σ / average single yarn fiber diameter r × 100 (%)

(3) Fineness of ultrafine fiber Fineness of ultrafine fiber obtained from fineness D of sea-island type composite fiber (measured by the method described in section (1) above) and weight loss Ra when sea polymer is dissolved Was calculated by the following formula.
Fineness of extra fine fiber = D × (1-Ra)

(4) Tensile strength and elongation at break of ultrafine fiber A cylindrical braid having a mass of 1 g or more was prepared from the sea-island composite fiber, and the knitted fabric was treated with a solvent to remove sea components. The obtained knitted fabric made of ultrafine fibers was unwound, and a load-elongation curve chart of the obtained ultrafine fibers was prepared under conditions of room temperature, initial sample length = 200 mm, and tensile speed = 200 mm / min. From the above chart, the tensile strength (cN / dtex) and elongation at break (%) of the ultrafine fiber were determined.

(5) Dry heat shrinkage rate Using ultrafine fiber, the sample was beaten 10 times using a measuring machine with a frame circumference of 1.125 mm to create a skein, and the length L0 under a load of 1/30 cN / dtex was determined. It was measured. The load was removed from the skein, placed in a constant temperature dryer in a free state, and subjected to a heat treatment at 150 ° C. for 30 minutes. A load of 1/30 cN / dtex was applied to the dried skein, and the skein length L1 after the dry heat treatment was measured. The dry heat shrinkage ratio HDS of this ultrafine fiber was calculated from the following formula.
HDS (%) = [(L0−L1) / L0] × 100

(6) Melt viscosity The polymer is dried, set in an orifice set at the melt temperature of an extruder for melt spinning, held in a molten state for 5 minutes, and then extruded under a predetermined level of load. The shear rate at this time And melt viscosity were plotted. The above operation was repeated under multiple levels of load. Based on the above data, the melt viscosity at a shear rate of 1000 sec- ¹ is estimated.

[Example 1]
Polyethylene naphthalate with an intrinsic viscosity of 0.62 (35 ° C. in orthochlorophenol) as an island component, and 9 mol% of 5-sodium sulfoisophthalic acid and 3% by weight of polyethylene glycol with a number average molecular weight of 4000 as a sea component A sea-island type composite fiber was obtained by using polyethylene terephthalate having a viscosity of 0.49 and using the method of W02005 / 095686. The melt viscosity of each of the sea component and the island component was 283 Pa · s and 250 Pa · s, and the melt viscosity ratio (sea / island) of the polymer was 0.9. After melting separately, they are merged in a composite die, and sea-island type unstretched fibers with sea: island = 30: 70 and number of islands = 900 are melt-spun at a spinning temperature of 300 ° C. and a spinning speed of 1000 m / min, and wound. It was. The obtained undrawn yarn was roller-drawn at a drawing temperature of 130 ° C. and a draw ratio of 3.9 times, and then heat-set by a non-contact heater at 200 ° C. to obtain a sea-island type composite drawn yarn. In the drawing process, no fluff or yarn breakage occurred, and all undrawn yarns could be drawn without problems. The obtained sea-island type composite stretched yarn was 62 dtex / 10 fil, and a tubular knitting was prepared. When the weight was reduced for 1 minute in an alkaline solution at 98 ° C. and 3.5 g / l, only the sea components were eluted. The average single yarn fiber diameter of the component was 700 nm, CV% was 12%, strength was 5.8 cN / dtex, elongation was 25%, and dry heat shrinkage was 1.5%.

[Example 2]
The same procedure as in Example 1 was performed except that polyethylene naphthalate having an intrinsic viscosity of 0.50 (35 ° C. in orthochlorophenol) was used as the island component. The melt viscosity of each of the sea component and the island component was 212 Pa · s and 213 Pa · s, and the melt viscosity ratio (sea / island) of the polymer was 1.0. After melting separately, they are merged in a composite die, and sea-island type unstretched fibers with sea: island = 30: 70 and number of islands = 900 are melt-spun at a spinning temperature of 300 ° C. and a spinning speed of 1000 m / min, and wound. It was. The obtained undrawn yarn was subjected to roller drawing at a drawing temperature of 130 ° C. and a draw ratio of 3.9 times, and then heat-set with a non-contact heater at 200 ° C. to obtain a sea-island type composite fiber. In the drawing process, no fluff or yarn breakage occurred, and all undrawn yarns could be drawn without problems. The obtained sea-island type composite stretched yarn was 62 dtex / 10 fil, and a tubular knitting was prepared and subjected to a weight reduction treatment in an alkaline solution of 98 ° C. and 3.5 g / 1 for 1 minute. As a result, only sea components were eluted. The average single fiber diameter of the island component was 700 nm, CV% was 12%, strength was 4.5 cN / dtex, elongation was 23%, and dry heat shrinkage was 2.0%.

[Comparative Example 1 ]
Polyethylene naphthalate with an intrinsic viscosity of 0.50 (35 ° C. in orthochlorophenol) as the island component, and 9 mol% of 5-sodiumsulfoisophthalic acid and 3% by weight of polyethylene glycol with a number average molecular weight of 4000 as the sea component The same procedure as in Example 1 was performed except that polyethylene terephthalate having a viscosity of 0.42 was used. The melt viscosity of each of the sea component and the island component was 114 Pa · s and 213 Pa · s, and the melt viscosity ratio (sea / island) of the polymer was 0.54.

After melting separately, they are merged in a composite die, and sea-island type composite unstretched fibers of sea: island = 50: 50, number of islands = 900 are melt-spun at a spinning temperature of 300 ° C. and a spinning speed of 1000 m / min, and wound. It was.
The obtained undrawn yarn was roller-drawn at a drawing temperature of 130 ° C. and a draw ratio of 3.7 times, and then heat-set with a non-contact heater at 200 ° C. to obtain a sea-island type composite drawn yarn. In the drawing process, no fluff or yarn breakage occurred, and all undrawn yarns could be drawn without problems. The obtained sea-island type composite stretched yarn was 64 dtex / 10 fil, and a tubular knitting was prepared and subjected to a weight loss treatment at 98 ° C. in an alkaline solution of 3.5 g / l for 3 minutes. As a result, only the sea component was eluted. The average fiber diameter of the island component was 610 nm, CV% was 15%, strength was 3.8 cN / dtex, elongation was 30%, and dry heat shrinkage was 2.8%.

  The polyester microfiber of the present invention is used for environmental and industrial material applications such as filters, harmful substance removal products, battery separators, vehicle interior products such as car seats, interior products such as carpets, sofas, curtains, cosmetics, cosmetic masks, Use for daily use such as wiping cloth and health care products, medical use such as polishing cloth, suture thread, scaffold, artificial blood vessel, blood filter, and clothing such as jackets, skirts, pants and underwear, sports clothing, clothing materials Can do.

Claims (3)

  It consists of polyethylene naphthalate, its single yarn fiber diameter is 10 to 1000 nm, single fiber diameter variation (CV%) is 0 to 12%, tensile strength is 4.0 cN / dtex or more as an ultrafine fiber bundle, elongation at break A polyester microfiber characterized by having a dry heat shrinkage of 10% to 80% at 150 ° C. and 5% or less.   A textile product comprising the polyester microfiber according to claim 1. Polyethylene naphthalate is used as the island component polymer, the solubility is higher than the island component polymer as the sea component polymer, and the melt viscosity ratio (sea / island) with respect to the island component polymer is within the range of 0.8 to 2.0. A sea-island type composite fiber was melt-spun at a take-up speed of 1000 to 3000 m / min using a readily soluble polymer, and then preheated on a preheating roller at 100 to 150 ° C. to obtain a draw ratio of 1.1 to 6. The method for producing a polyester ultrafine fiber according to claim 1, wherein the sea component of the sea-island type composite fiber drawn at 0 times and subsequently heat-set at a yarn temperature of 120 to 250 ° C is removed .