JP3389968B2 - Polyester staple fiber for wet-type nonwoven fabric having latent crimp development and method for producing the same - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyester short fiber for wet non-woven fabric having a latent crimping property suitable for producing a stretchable polyester non-woven fabric which has an excellent non-woven fabric processing speed, a low basis weight and a good texture and its production. It is about the method.

[0002]

2. Description of the Related Art Conventionally, polyester composite short fibers having latent crimp-developing properties have been known for use as stretchable polyester nonwoven fabrics, and have been used as constituent materials for various sanitary materials such as puppet materials required to have stretchability. There is.

However, with conventional polyester fibers having latent crimp developability, crimps (= elastic crimps) due to stress in the direction of the fiber axis are likely to appear in the dry nonwoven fabric production line, and when the fibers are formed into an aggregate. The uniform opening on the cylinder of the card opening machine, which is a generally performed process, is obstructed, and the texture of the card web becomes poor when the open web is scraped by the fly comb, resulting in poor quality. I could only make non-woven fabric. Further, due to fiber damage caused by cards and needle punches, a stretchable nonwoven fabric that does not necessarily take advantage of the properties of the fiber is not necessarily produced, and if the conditions are taken into consideration, there is a problem that productivity is reduced. Furthermore, when a nonwoven fabric is used, only the elastic recovery rate of the polymer itself is low, so that only the elongation recovery rate of the nonwoven fabric is poor.

[0004]

DISCLOSURE OF THE INVENTION The present invention eliminates the above-mentioned drawbacks relating to the production of a stretchable nonwoven fabric, and produces a stretchable nonwoven fabric having high elongation recovery when made into a nonwoven fabric without lowering the nonwoven fabric production line speed. The present invention provides a polyester short fiber for a wet non-woven fabric having a latent crimp suitable for

[0005]

[Means for Solving the Problems] Means for solving the above problems, that is, the present invention, is a side-by-side type or eccentric sheath-core type fiber in which polyester A is polypropylene terephthalate and polyester B is polyethylene terephthalate. And the weight ratio of polyester A to polyester B is 30:70 to 70:30 and the following conditions are satisfied.
Polyester short fibers for wet non-woven fabric having latent crimp development, characterized by satisfying (1) and (2) , μ (W) ≦ 0.2 (1) μ (W) / μ (D) ≦ 0.7 (2) μ (W): Coefficient of friction between fibers when wet μ (D): Coefficient of friction between fibers when dry Also, the cut length is 2 to 100 mm and the fineness is 0.5.
Wet-laid nonwoven fabric for polyester staple fibers having latent crimp of claim 1 wherein the 6 denier, further Poriesu <br/> ether A polypropylene terephthalate, side-by-polyethylene terephthalate polyester B
It is a side type or eccentric sheath / core type fiber, and the weight ratio of polyester A and polyester B is 30:70 to 70 :.
It melts at a temperature 10 to 30 ° C higher than the melting point of each component so that it becomes 30, and is a side-by-side type or an eccentric sheath.
Composite spinning into a core type and processing temperature 100 to 19 in the drawing process
After tension heat treatment at 0 ° C, the following inter-fiber frictional characteristics are
Cut surface length of 2-1 by applying surface treatment agent and oil
It is a method for producing polyester short fibers for a wet non-woven fabric having latent crimp expression, which is characterized in that it is cut into 00 mm. μ (W) ≦ 0.2 (1) μ (W) / μ (D) ≦ 0.7 (2) μ (W): Coefficient of friction between fibers when wet μ (D): Friction between fibers when dry coefficient

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION Polypropylene terephthalate, which is the main component of polyester A used in the present invention,
A polyester containing terephthalic acid as a main dicarboxylic acid component and trimethylene glycol as a main glycol component, and having a trimethylene terephthalate unit as a main repeating unit, and ethylene glycol, butanediol, etc. within a range not impairing the characteristics. The glycols, isophthalic acid, dicarboxylic acids such as 2,6-naphthalenedicarboxylic acid, and the like may be copolymerized. In view of mechanical properties, the intrinsic viscosity is 0.5 or more, more preferably 0.7 or more.

Polyethylene terephthalate, which is the main component of polyester B used in the present invention, is a polyester which contains terephthalic acid as a main dicarboxylic acid component and ethylene glycol as a main glycol component, and has ethylene terephthalate units as main repeating units. By copolymerizing glycols such as butanediol, isophthalic acid, dicarboxylic acids such as 2,6-naphthalenedicarboxylic acid, etc. within a range that does not disturb the balance of the heat shrinkage ratio and the elastic recovery ratio with the polyester A. Is also good.

The composite ratio of polyester A and polyester B in the present invention is 5 in the side-by-side type.
It can be changed around 0:50 within a range that does not impair the intended effect of the present invention, and is preferably 30:70 to 70:30, and more preferably 40:60 to 60-40. Also, the eccentric sheath
Also in the case of the core, the composite ratio of the polyester A and the polyester B can be changed within a range not to impair the intended effect of the present invention, centering around 50:50, and the ratio is 30:70 to 70:30.
It is preferably 40:60 to 60:40.

The cut length of the polyester short fiber of the present invention is 2 when the dispersibility in water and the strength of the nonwoven fabric are taken into consideration.
~ 100mm is preferred, more preferably 5 ~ 20mm
Is. Further, the fineness is preferably 0.5 to 6.0 denier from the viewpoint of the texture of the paper-made nonwoven fabric. If it is thinner than 0.5 denier, a fiber lump is likely to be formed when the fiber dispersion is stirred, and if it is thicker than 6 denier, it is difficult to obtain a paper-like nonwoven fabric having a soft texture.

Regarding the inter-fiber friction coefficient in the present invention, when μ (W)> 0.2, the dispersibility of the polyester fiber in water is deteriorated, and it is necessary to add agents such as a dispersant and a sticky agent at the time of papermaking. Occurs, and it becomes difficult to obtain a uniform paper-like nonwoven fabric. Also, μ (W) / μ (D)> 0.7
If so, the occurrence of fly flies increases in the polyester short fiber manufacturing process, and various troubles are likely to occur.

Examples of the surface treating agent for the polyester fiber of the present invention include polyalkylene glycol and / or its derivative. The polyalkylene glycols, polyethylene oxide, polypropylene oxide, Poriteto La methylene oxide, and the like, also made of any combination of this is found also preferred. The derivative is a polycondensation product of an acid component at the terminal thereof, and the acid component includes a terephthalic acid component, an isophthalic acid component, a benzenesulfonic acid alkali metal salt component, a higher fatty acid component, a monocarboxylic acid component and the like. It can be illustrated.

Further, the average molecular weight of these is 50,000 to 15
It is preferably in the range of 0,000, and more preferably in the range of 100,000 to 1,000,000. When the average molecular weight is less than 50,000, the coefficient of friction between fibers when wet becomes large and the dispersibility of the polyester fiber in water deteriorates. If the average molecular weight exceeds 1,500,000, the viscosity of the treating agent itself increases,
Problems such as machine stains and roll wrapping are likely to occur in the step of applying the polyester fiber.

The amount of the above-mentioned treatment agent attached to the polyester fiber is preferably in the range of 0.1 to 2% by weight, and 0.2 to
1% is more preferable. When the adhesion rate is lower than 0.1% by weight, the dispersibility of the polyester fiber in water becomes poor,
If it is higher than 2% by weight, the dispersibility will not be improved further,
Not only is the processing agent wasted, but problems such as stains and roller wrapping during the process of applying to the polyester fiber are likely to occur.

Further, the cross-sectional shape of the fiber is a modified cross section or a hollow cross section, so that the bulkiness, texture, and
A function such as water movement due to a capillary phenomenon is imparted, which is preferable. Further, surface modifiers and additives for imparting antistatic property, flame retardant property, antibacterial property, deodorant property, easy-feeling property, etc. and a third component are optionally compounded within a range not impairing the intended effects of the present invention. can do.

The polyester fiber for papermaking having latent crimpability of the present invention is melted at a temperature higher than the melting point by 10 to 30 ° C. by a well-known polyester two-component spinning device, and is merged just before the orifice for composite spinning. The intrinsic viscosities of polyester A containing polypropylene terephthalate as the main component and polyester B containing polyethylene terephthalate as the main component are 10 to 30 ° C. higher than the melting point and melted at the same temperature because of stable polymer discharge from the spinning nozzle during melt spinning. It is preferable to set the viscosity difference to be 500 poise or less. The melt spun yarn may be cooled by either uniform cooling or asymmetric cooling as long as the effects of the present invention are not impaired. After cooling and drawing, the undrawn yarn thus obtained is subjected to two-stage or three-stage drawing. For example, the first step is performed at a tow temperature of 50 to 100 ° C. and a breaking stretch ratio (MDR) of 0.70 to 0.75. The second stage is M
It is performed at 0.80 to 0.85 times DR. In addition, if necessary for the purpose of use, the third stage stretching is 0.
9 to 0.95 times. After the drawing and oiling process, it is cut into a predetermined cut length (5 to 100 mm) and manufactured.
After the multi-stage stretching or the three-stage stretching, it is necessary to perform a tension heat treatment at a heat treatment temperature of 100 to 190 ° C. Polyester A containing polypropylene terephthalate as a main component of the present invention,
The polyester short fibers for wet non-woven fabrics having latent crimping properties of the present invention, which are obtained by combining with polyester B containing polyethylene terephthalate as a main component, have high latent crimping developability and are not subjected to heat treatment in a tensioned state during stretching or When the tension heat treatment is performed at a temperature of 100 ° C. or less, the degree of latent crimps developed during the heat treatment becomes too large, and when the nonwoven fabric is formed, preferable entanglement between fibers is inhibited and the stretchability of the nonwoven fabric is poor. become. Also, 190 ℃
When the tension heat treatment is carried out at the above temperature, the latent crimp developability is lowered and the fiber assembly becomes inferior in elongation recovery.

[0016]

EXAMPLES Examples will be shown below. The methods for measuring physical properties and the like in Examples and the text are as follows. (1) Intrinsic viscosity Parachlorophenol solvent used, 25
Measured by ordinary method at ℃ (2) Fineness Measured by the method of JIS-1015-7-5 (3) Collected in a tow state immediately before cutting the coefficient of friction between fibers in dry and wet, and dried at 100 ℃ The coefficient of friction between fibers when dried is defined as the coefficient of friction between fibers when dried, and the coefficient of friction between fibers when wet is measured as it is without being dried. The measurement of the friction coefficient between fibers is JIS-L101.
The radar method of 5 is used, and when it is wet, the fiber part to be measured is modified so that it is immersed in water. The peripheral speed of the cylinder during measurement is 2 cm / min. (4) Dispersibility evaluation method A 200 cc beaker was charged with 50 cc of distilled water and 0.25 g of polyester fiber (substantial weight) and stirred with a magnetic stirrer for 5 minutes. afterwards,
Transfer to a 1000cc graduated cylinder and add 5 with distilled water.
Dilute to 00cc, cover the graduated cylinder, rotate once in the vertical direction to disperse the fibers, count the number of binding fibers contained in this, and check the dispersion state of the fibers from the spread state in water. judge. ◎: Very good ○: Good Δ: Intermediate ×: Poor (5) Method for preparing wet non-woven fabric First, short fibers were dispersed in water so that the slurry concentration was 0.15%, and then water was removed to form a sheet. State Then, the fibers are entangled with a water punch, and then heat-treated at 160 ° C. for 60 seconds to prepare a stretchable nonwoven fabric having a basis weight of 30 g / m ² and a thickness of 0.3 mm. (6) Cut the unit weight test piece into 20 cm x 20 cm, and keep it for 24 hours or more under standard conditions (temperature 20 ± 2 ° C , relative humidity 65 ± 2).
% RH) and weigh it with a weight balance to determine the unit area (1
The weight per cm ² ) (g / cm ² ) represents the basis weight. (7) Thickness The thickness of the sample is measured at arbitrary 5 points with DIAL GAUGE (compression plate φ30 mm, 80 g) manufactured by OZAKI, and the average value is obtained. (8) 50% elongation recovery rate A test piece of 50 mm x 200 mm was attached to a constant speed extension type tensile tester with an automatic recording device as a gripping width, and was attached at 100 mm in the line direction of the paper-like non-woven fabric, at a pulling speed of 500 mm / min of 50 mm. After pulling and returning to the original position at the same speed, drawing a load-elongation curve and extending 50 mm, the elongation (a) at the returning position is used to express the 50% elongation recovery rate by the following formula. 50% elongation recovery rate = (50−a) / 50) × 100

Examples and Comparative Examples As polyester A,
Intrinsic viscosity = 0.83 polypropylene terephthalate 1
00%, 100% polyethylene terephthalate with an intrinsic viscosity of 0.63 as polyester B, using a composite spinning device, the composite ratio and the fiber cross section shown in Table 1 from the round cross section spinneret hole to the nozzle spinneret temperature of 285 ° C. Discharge rate 1.07 g /
The unstretched yarn was obtained by winding at 1900 m / min.
These undrawn yarns were treated with a MDR of 0.75 in a warm bath at 75 ° C.
The first-stage stretching is performed at a draw ratio of 2 times, followed by the second-stage drawing at a draw ratio of 0.80 times MDR under steam heating at 100 ° C. by steam, and then a tension heat treatment is performed at 160 ° C. The surface treatment agent shown in Table 2 was applied in the oil agent applying step, and cut into a fiber length of 10 mm with an Eastman cutter,
A short fiber of the present invention having a fineness of 2.5 denier was obtained. afterwards,
A wet nonwoven fabric was prepared by the above method. The effects of the composite type and the composite ratio of the fibers are shown in Table 1, and the effects of the fiber surface treatment agent and the adhesion rate are shown in Table 2.

[0018]

[Table 1]

[0019]

[Table 2]

[0020]

EFFECT OF THE INVENTION The fiber produced by such a method has excellent dispersibility in the papermaking process, and after the heat treatment, latent crimps are developed, so that the stretchable nonwoven fabric has a low basis weight and an excellent elongation recovery property. Can be provided.

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Claims (3)

(57) [Claims] 1. Polyester A is polypropylene terephthalate and polyester B is polyethylene terephthalate.
In side-by-side type or eccentric sheath-core type fiber is, the weight ratio of the polyester A and the polyester B is 3
0:70 to 70:30 and the following condition (1) and
(2) A polyester short fiber for wet non-woven fabric having latent crimp expression, which satisfies the condition (2) . μ (W) ≦ 0.2 (1) μ (W) / μ (D) ≦ 0.7 (2) μ (W): Coefficient of friction between fibers when wet μ (D): Friction between fibers when dry coefficient 2. A polyester short fiber for a wet non-woven fabric having latent crimp developability according to claim 1, which has a cut length of 2 to 100 mm and a fineness of 0.5 to 6 denier. 3. A polyester A is polypropylene terephthalate and a polyester B is polyethylene terephthalate.
Which is a side-by-side type or eccentric sheath-core type fiber having a weight ratio of polyester A to polyester B of 30:70 to 70:30, which is 10 to 30 ° C. higher than the melting point of each component. in melted, side-by-side type or eccentric sheath-core type composite spinning, after tension heat treatment at a treatment temperature 100 to 190 ° C. in the stretching process, the following fiber
A process for producing a polyester short fiber for wet non-woven fabric having latent crimp development, which comprises applying a surface treatment agent for imparting fiber friction characteristics to a fiber and oil, and cutting the fiber into a cut length of 2 to 100 mm. μ (W) ≦ 0.2 (1) μ (W) / μ (D) ≦ 0.7 (2) μ (W): Coefficient of friction between fibers when wet μ (D): Friction between fibers when dry coefficient