JPH11100768A - Polyester filament nonwoven fabric - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a polyester filament nonwoven fabric extremely little in the breakage of the filaments, having a proper elastic property, a soft touch and a uniform metsuke(a weight unit), and useful as a material for wrapping body warmers and the like by allowing the filaments to have a prescribed strength, a prescribed elastic modulus and a prescribed elastic recovery factor. SOLUTION: This polyester filament nonwoven fabric comprises a polytrimethylene terephthalate (intrinisic viscosity is preferably 0.6-1.2) having an oligomer content of <=3 wt.%. Therein, the filaments constituting the nonwoven fabric have a strength of 0.7-4 g/d, an elastic modulus of 15-40 g/d and an elastic recovery factor of 70-100% on an elongation of 20%.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyester filament nonwoven fabric obtained by a spunbond method,
More specifically, the present invention relates to a polyester long-fiber nonwoven fabric having moderate stretchability, soft texture, uniform basis weight, extremely few thread breaks, and an extended wiping cycle, and excellent spinning stability.

[0002]

2. Description of the Related Art Polytrimethylene terephthalate obtained by polycondensing a lower alcohol ester of terephthalic acid represented by terephthalic acid or dimethyl terephthalate with trimethylene glycol (1,3-propanediol) has excellent elasticity. It is an epoch-making polymer that combines properties similar to polyamide, such as recovery, low elastic modulus, and easy dyeability, and properties similar to polyethylene terephthalate, such as light resistance, heat setting, dimensional stability, and low water absorption. BCF carpet, brush,
It is applied to tennis gut and the like (Japanese Patent Laid-Open No. 9-3724)
JP, JP-A-8-173244, JP-A-5-25-2
No. 62882).

On the other hand, among existing spunbonded nonwoven fabrics, nonwoven fabrics made of polymers such as polyamide, polyethylene terephthalate, and polypropylene have been put on the market. For example, they have been developed for applications such as disposable body warmers, furoshiki, and tablecloths. However,
Non-woven fabrics made of existing non-woven fabrics have poor elasticity. Performance becomes insufficient. As a result, the warming effect of Cairo cannot be sufficiently exhibited. In addition, the texture is hard in a known nonwoven fabric,
There was a drawback that the wearing feeling of Cairo was bad.

Next, the production of a spunbonded nonwoven fabric using polytrimethylene terephthalate will be considered. Polytrimethylene terephthalate can be spun basically in the same manner as polyethylene terephthalate because of the similarity in its molecular structure.However, when a polymer obtained by a known polytrimethylene terephthalate polymerization technique is used, Due to the high content of oligomers and low molecular impurities therein, a white powdery substance precipitates around the spinneret with the spinning time. Since these deposits cause yarn breakage and fluff, wiping (cleaning the spinning surface with a metal spatula while spraying a silicone release agent onto the spinning surface) is performed with considerable frequency. There is a need to do. Spunbonded nonwoven fabric usually has a spinning number of 300 or more, especially 1
Since 2,000 or more are frequently used, an increase in the number of wiping operations as compared with ordinary melt spinning (the number of spinning holes is at most about 100) leads to an increase in cost and a decrease in productivity, which is a serious problem. In addition, due to the presence of these impurities, the non-uniformity of the nonwoven fabric becomes a problem.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to have an excellent spinning stability having a moderate stretchability, a soft texture, a uniform basis weight, extremely few thread breaks and an extended wiping cycle. The purpose is to obtain a polyester long fiber nonwoven fabric.

[0006]

Means for Solving the Problems The inventors of the present invention have drawn in detail the drawback of the stretching property of polytrimethylene terephthalate long-fiber nonwoven fabric and the improvement of spinning stability from the viewpoint of polymer polymerization, spinning conditions and structural design of the nonwoven fabric. After investigation, the present invention has been reached. That is, the present invention relates to a long-fiber nonwoven fabric comprising polytrimethylene terephthalate having an oligomer content of 3 wt% or less, wherein the fibers constituting the nonwoven fabric have a strength of 0.7 to 4 g / d and an elastic modulus of 15%. ~ 40
It is a polyester long-fiber nonwoven fabric characterized in that the elastic recovery rate at g / d and 20% elongation is 70 to 100%.

The polymer used in the present invention is substantially composed of polytrimethylene terephthalate, and the content of the oligomer must be 3 wt% or less. Here, “substantially” means that it may be a polytrimethylene terephthalate homopolymer or a polytrimethylene terephthalate copolymer shown below. That is, when using a polytrimethylene terephthalate copolymer, ethylene glycol, 1,4-butanediol, 1,6-hexanediol, 2,6-naphthalenecarboxylic acid, isophthalic acid, adipic acid, succinic acid, polyethylene glycol, A monomer copolymerizable with polytrimethylene terephthalate such as tetramethylene glycol, 5-sodium sulfoisophthalic acid, and tetrabutylphosphonium 5-sulfoisophthalate may be copolymerized. Also, if necessary, various additives such as matting agents, heat stabilizers, defoaming agents, tinting agents, flame retardants, antioxidants, ultraviolet absorbers, infrared absorbers, crystal nucleating agents, fluorescent light A whitening agent or the like may be copolymerized or mixed.

The polymer used in the present invention must have a trimethylene terephthalate oligomer content of 3% by weight or less. Spinning stability can be ensured within this range, and so-called fine denier nonwoven fabric can be produced. I do.
The trimethylene terephthalate oligomer is generally an oligomer in which trimethylene terephthalate units are connected by 2 to 4, and may have a linear structure or a cyclic structure. If the amount exceeds 3 wt%, for example, when spinning, the oligomer precipitates around the spinneret, causing not only yarn breakage and fluffing, but also oligomers hinder uniform spinning. Causes eye spots. In order to perform long-time spinning, the content is preferably 1.5 wt% or less, more preferably 1 wt% or less. Furthermore, in terms of reducing the fluff and spots of the obtained fibers, the content of 0.1% is preferable.
5 wt% or less, more preferably 0.3 wt%
The following are, of course, ideally not included.

Further, the content of an organic substance having a molecular weight of 300 or less is preferably 1 wt% or less in the polymer used in the present invention. Within this range, the wiping cycle is further extended and no coloring occurs, and the light resistance is excellent. Such performance can be secured. Here, the organic substance having a molecular weight of 300 or less is an organic substance that is not copolymerized with a polymer. According to the study of the present inventors, as an organic substance having a molecular weight of 300 or less,
Allyl alcohol, acrolein, 2-butanol, hexanol, heptanol, glycidyl methyl ether, oxypropyl methyl ether, and the like are present, and it has been found that the total amount of these compounds greatly affects moldability, product durability, and weather resistance. . When the content of the organic substance having a molecular weight of 300 or less exceeds 1% by weight, for example, yarn breakage or fluff is likely to occur at the time of spinning, or coloring tends to occur with light. Preferably molecular weight 30
0 or less organic matter content is 5000 ppm or less,
Especially preferably, it is 1000 ppm or less. of course,
Ideally free.

The melting point of the polymer used in the present invention is as follows:
The temperature is preferably 227 ° C. or higher. Here, the melting point is
It is defined as the peak value of the peak considered to be melting in the range of 220 to 250 ° C. When there are a plurality of melting peaks (including a shoulder peak), the lower temperature peak is used as the melting point. If the melting point is less than 227 ° C., the weather resistance tends to decrease. For example, once polytrimethylene terephthalate is synthesized and the polymer is solid-phase polymerized at about 200 ° C., the oligomer content can be significantly reduced. However, when the solid-phase polymerization is performed, the melting point of the raw material polymer is greatly reduced to a state of less than 225 ° C. Among such polymers, bis-3-hydroxypropyl ether generated by trimerization of trimethylene glycol is copolymerized in large amounts and the amount of terminal carboxyl groups increases, resulting in spinning stability and weather resistance. Tends to decrease. The preferred melting point of the polymer is 230 ° C. or higher, more preferably 233 ° C. or higher.

The intrinsic viscosity [η] of the polymer used in the present invention.
Is 0.4 to 2.0, preferably 0.5 to 1.5, more preferably 0.6 to 1.2. Within this range, a fiber having excellent strength and spinnability can be obtained. The intrinsic viscosity is 0.
When it is less than 4, spinning becomes unstable because the melt viscosity of the polymer is too low, and the strength of the obtained fiber is also low, which is not satisfactory. Conversely, if the intrinsic viscosity exceeds 2.0, the melt viscosity is too high, and melt fracture or poor spinning occurs during spinning.

As a preferable example of the method for producing the polymer used in the present invention, terephthalic acid or dimethyl terephthalate is used as a raw material, and trimethylene glycol is added to calcium acetate, magnesium acetate, zinc acetate, cobalt acetate, manganese acetate. Metal acetate 1
One or more species are added in an amount of 0.03 to 0.1% by weight, and bishydroxypropyl terephthalate is obtained at a transesterification rate of 90 to 98% under normal pressure or pressure. As described above, in order to achieve the object of the present invention, it is preferable to use a metal acetate other than a transition metal. Next, one or more catalysts such as titanium tetraisopropoxide, titanium tetrabutoxide, and antimony trioxide are used in an amount of 0.03 to 0.15 wt%, preferably 0.03 to 0.15 wt%.
1 wt% is added, and the reaction is performed under reduced pressure at 250 to 270 ° C. It is preferable to add a stabilizer at any stage of the polymerization, preferably before the polycondensation reaction, from the viewpoint of controlling the whiteness of the resin composition, the amount of the polytrimethylene terephthalate oligomer or the organic substance having a molecular weight of 300 or less to a specific amount. .

In this case, the stabilizer may be pentavalent or / and / or
And trivalent phosphorus compounds and hindered phenol compounds are preferred. Examples of the pentavalent and / or trivalent phosphorus compound include trimethyl phosphate, triethyl phosphate, tributyl phosphate, triphenyl phosphate, trimethyl phosphite, triethyl phosphite, tributyl phosphite, triphenyl phosphite, and the like. Phosphite is preferred. The hindered phenolic compound is a phenolic derivative having a substituent having steric hindrance at a position adjacent to the phenolic hydroxyl group, and is a compound having one or more ester bonds in the molecule.

Specifically, pentaerythritol-tetra extract [3 (3,5-di-tertbutyl-4-hydroxyphenyl) propionate], 1,1,3-tris (2-methyl-4-hydroxy-5 -Tert-butylphenyl) butane, 1,3,5-trimethyl-2,4,6-
Tris (3,5-di-tert-butyl-4-hydroxybenzyl) benzene, 3,9-bis {2- [3- (3-te
rt-butyl-4-hydroxy-5-methylphenyl) propionyloxy] -1,1-dimethylethyl} -2,
4,8,10-tetraoxaspiro [5,5] undecane, 1,3,5-tris (4-tert-butyl-3-hydroxy-2,6-dimethylbenzene) isophthalic acid, triethylglycol-bis [3 (3-tert-butyl-5
-Methyl-4-hydroxyphenyl) propionate], 1,6-hexanediol-bis [3- (3,5
-Di-tert-butyl-4-hydroxyphenyl) propionate], 2,2-thio-diethylene-bis [3
(3,5-di-tertbutyl-4-hydroxyphenyl)
Propionate], octadecyl-3- (3,5-di-
tert-butyl-4-hydroxyphenyl) propionate]. Among them, pentaerythritol-tetra extract [3 (3,5-di-tertbutyl-4)
-Hydroxyphenyl) propionate] is preferred.

The polymer obtained by the above method generally has the following properties. The content of the copolymerized bis-3-hydroxypropyl ether is 0.1 wt% or less. The hue is 10 or less when represented by the b value, and 3 or less in some cases. The amount of terminal carboxyl groups is 10
３５35 mg equivalent / kg. The polyester long fiber nonwoven fabric of the present invention can be obtained by a spun bond method. That is, a large number of continuous filaments obtained by melt-spinning a polymer substantially consisting of polytrimethylene terephthalate and having an oligomer content of 3 wt% or less from a large number of spinnerets are subjected to a pulling action of an ejector or the like. After that, the web can be obtained by forming a web on the moving collecting device.

Here, the ejector has a function of drawing and thinning at high speed by using the pressurized air fed with the melt-spun filament as a driving force, and having a function of accompanying the filament with a high-speed air flow. The speed of the filament extruded from the ejector, that is, the spinning speed, generally reaches 2000 to 6000 m / min.
This speed is an index of the thinning of the single yarn, and the higher the speed, the thinner the fiber becomes and the finer the fiber becomes. The spinning speed is mainly governed by the selection of conditions such as the discharge amount, the position of the ejector, and the pressure of the supplied air.
The range of 000 to 5000 m / min is preferable.

The spinning temperature at the time of melt spinning is 230 to 32.
0 ° C, preferably 235-300 ° C, more preferably 2 ° C
A range from 40 to 280C is suitable. Spinning temperature is 230
When the temperature is lower than 0 ° C, the temperature is too low to be in a stable molten state, the resulting fibers have large irregularities, and no satisfactory strength is exhibited. On the other hand, when the spinning temperature exceeds 320 ° C., thermal decomposition becomes severe, and the obtained yarn is colored and does not show satisfactory strength and elongation. The shape of the spinneret used is not particularly limited, such as a circle, a triangle, a polygon, and a flat shape, but is usually a circle having a diameter of about 0.1 to 0.5 mm. The number of spinnerets that are open to the whole spinneret is usually 10 to
The number is about 3000.

The fineness of the filaments constituting the polyester long-fiber nonwoven fabric of the present invention is preferably 0.5 to 10 d. If it is larger than 10 d, the cooling becomes insufficient and the resulting nonwoven fabric becomes hard. On the other hand, when it is smaller than 0.5 d, the filament cannot withstand the tension of the ejector, and a part of the filament is cut. Preferably, it is 1 to 4d. The preferred basis weight is 10 to 50 g / m ² . As described above, in the polyester long-fiber nonwoven fabric of the present invention, the content of the oligomer is regulated to 3 wt% or less.
Thus, it is a very high-quality nonwoven fabric having a fine denier and no spots.

The filament constituting the nonwoven fabric of the present invention has a strength of 0.7 to 4 g / d, an elastic modulus of 15 to 40 g / d,
It is necessary that the elastic recovery rate at 20% elongation is 70 to 100% in order to develop appropriate elasticity and soft texture. When the strength of the filament is less than 0.7 g / d, the filament cannot withstand the tension of the ejector, and a part of the filament is cut. Meanwhile, 4g
It is practically impossible to make it equal to or more than / d. Elastic modulus is 15
If it is less than g / d, the texture becomes very soft, but it is not preferable because the processability decreases. If it is 40 d / d or more, the texture becomes hard. 7% elastic recovery at 20% elongation
Below 0%, for example, when applied to a disposable body warmer,
Non-woven fabric is less likely to follow the continuous expansion and contraction of the body,
It is not preferable because it causes tarmi. Preferred strength is 1 to 4 g / d, preferred elastic modulus is 20 to 40 g / d,
The preferred elastic recovery at 20% elongation is 75 to 100%. Such filament properties can be achieved by applying the preferable spinning conditions described above.

The filament group ejected from the outlet of the ejector or the like together with the air flow further travels at a movable porous receiver provided thereunder, specifically, at a constant speed made of metal or resin. At this time, the filaments ejected from the ejector, etc. are easily collected in a unit of ejection, and the spread of the collected web is narrow. In particular, when there is a tendency to lack quality, it is effective to devise a method in which the filaments are ejected and collected in a state where they are separated from each other.

In order for the filaments to be ejected and collected in a state in which they are separated from each other, a collision member is provided below an ejector or the like, and the filament is caused to collide with the collision member so as to be collected. And a method of causing the filament to open after frictional charging has occurred, or a method in which the filament is forcibly charged by corona discharge immediately before being guided to an ejector to open the fiber.
If the collected web does not reach a desired spread even by these fiber charging and fiber opening techniques, a mechanism such as a mechanical swinging or rotating mechanism is provided for a member such as an ejector or a collision member. Making it effective is also effective.

At the time of collecting such a web, the web once deposited may be blown and disturbed due to the air flow hitting the receiver along with the filament. To prevent this phenomenon, It is preferable to employ means for sucking air from below the receiver. It is preferable that the polyester long-fiber nonwoven fabric of the present invention obtained as described above is further subjected to a press treatment under heating at, for example, 80 to 240 ° C. A thermal stabilization process can be performed. The pressing may be performed using a pair of heated flat plates, or may be performed using a heated roller or the like. In particular, since it is effective from the viewpoint of maintaining the quality of the product to apply tension before and after the press treatment and to add auxiliary operations such as cooling after the press treatment, a continuous treatment method using a heating roller is suitable. ing.

The temperature and pressure of the hot press treatment are to be appropriately changed by selecting conditions such as the basis weight and speed of the supplied web-like material. The temperature is 200 to 240 ° C., and the pressure is preferably at least 10 kg / cm or more when the treatment is carried out by a heating roller, from the viewpoint of stabilizing the quality of the obtained polyester long-fiber nonwoven fabric.
As the above-mentioned heating roller, it is also possible to use a roller having a smooth surface, a pattern engraved, or a combination of the same kind or a plurality of different kinds of rotating rollers. The thermocompression bonding portion is preferably 30% or less of the total area of the thermocompression bonding portion with respect to the entire area of the nonwoven fabric, and more preferably in the range of 10 to 20% in order to exhibit good flexibility and bulkiness. preferable.

[0024]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail with reference to examples, but needless to say, the present invention is not limited to the examples. The main measured values in the examples were measured by the following methods. (1) Intrinsic Viscosity This intrinsic viscosity [η] is a value determined based on the following definition formula. [Η] = lim 1 / (C × (ηr-1)) C → 0 ηr in the definition formula is the same as the viscosity at 35 ° C. of a dilute solution of a polyester polymer dissolved in o-chlorophenol having a purity of 98% or more. It is a value obtained by dividing the viscosity of the solvent itself measured at a temperature, and is defined as a relative viscosity.
C is the solute weight value in grams in 100 ml of the solution.

(2) Quantification of PTT oligomer The finely divided polyester resin composition and polyester fiber were mixed with chloroform using a Soxhlet extractor with chloroform.
Extraction was carried out for a time, and a dimer or tetramer was extracted as an oligomer and expressed as a percentage by weight based on the sample used. (3) Structural determination and quantification of organic substance having a molecular weight of 300 or less From the chloroform solution obtained in (2), an organic substance having a molecular weight of 300 or less contained in the polyester resin composition and fibers was determined. The analysis was performed using gas chromatography equipped with a capillary column. The column used was of two types, a silicon type and a polyethylene glycol type. For each of the separated components, the mass spectrum (GC-M
Using S), a calibration curve was prepared for the weighing, and the concentration for the sample used was determined in ppm.

(4) Melting Point The melting point was measured using a DSC manufactured by Seiko Electronics Co., Ltd. at a heating rate of 20 ° C./min in a nitrogen stream of 100 ml / min.
Here, the peak value of the melting peak was defined as the melting point. (5) Bending resistance Evaluation was made according to JIS-1096 (45-degree cantilever method). The higher the number, the harder the texture.

(6) Elastic recovery at 20% elongation The elastic recovery was determined as an elastic recovery obtained by the following method. Attach the fiber to a tensile tester with a distance between chucks of 20 cm.
/ Min and let stand for 1 minute. Thereafter, it was returned to the original length (a) again at the same speed, and the moving distance of the chuck (residual elongation: a ') under the state where stress was applied at that time was read and determined according to the following equation. Elastic recovery rate = (aa ′) × 100 / a

(7) Peeling property at the time of expansion and contraction Using a composite structure laminated on a nonwoven fabric of 150 mm x 100 mm, leaving a 10 mm width at the center of the nonwoven fabric, affixing a commercially available gum tape (made of cloth) over the entire remaining surface, Were repeatedly gripped by a stretching tester (dematcher) and stretched at a rate of 60 times / min, and the number of times until peeling was evaluated. The larger the number, the harder it is to peel off.

(Example 1) Dimethyl terephthalate and 1,
3-propanediol was charged at a molar ratio of 1: 2, a mixture of calcium acetate and cobalt acetate (9: 1) corresponding to 0.1 wt% of the theoretical polymer amount was added, and the temperature was gradually increased, and transesterification was performed at 240 ° C. The reaction was completed. Titanium tetrabutoxide was added at 0.1 wt% of the theoretical polymer amount to the obtained transesterified product, and reacted at 270 ° C. for 2 hours. The intrinsic viscosity of the obtained polymer was 0.8. The content of the oligomer is 0.1 wt%, and the molecular weight is 300
The following organic matter amount was 350 ppm and the melting point was 234 ° C.

The obtained polymer is melted at 270 ° C., and the spinning speed is 3000 m / min while suctioning with an ejector.
After spinning, a web was prepared by depositing on a moving porous strip. This web was entirely thermocompression-bonded with a thermocompression bonding device consisting of a pair of flat rolls heated to 150 ° C. to obtain a nonwoven fabric having a basis weight of 40 g / m ² and a tensile strength of 7.0 g / 3 cm. The filament constituting this nonwoven fabric has a strength of 2.5 g / d, an elongation of 50%, an elastic modulus of 25 g / d,
% Elastic recovery at the time of elongation is 75%, moderate elasticity,
It had a soft texture. Furthermore, when spots were observed by irradiating light from the back side of the nonwoven fabric, substantially no thinned portions or portions in which filaments were solidified in a ball shape could not be substantially confirmed.

The spinning surface was clean even after one week of spinning. A non-breathable soft polyethylene film having a thickness of 30 μm was laminated on the obtained nonwoven fabric, and a material having a total perforated area of 6% was laminated by a hot pin method. This composite structure can be used as a bag for a disposable body warmer, but it has a very soft feel with a stiffness of just 58 mm and a width of 52 mm. The elastic peelability was a good result as compared with other materials without peeling up to 15 times.

Comparative Example 1 Example 1 was repeated except that 0.1 wt% of titanium tetrabutoxide was used as a transesterification catalyst. The oligomer content of the obtained polymer was 3.9 wt%, the amount of organic substances having a molecular weight of 300 or less was 1600 ppm, and the melting point was 233 ° C. Spinning was carried out using this polymer, but white organic matter was precipitated on the spinning surface and the yarn was broken without keeping for one day. When spots were observed by irradiating light from the back side of the nonwoven fabric surface, there was no thinned portion, but a portion where filaments were hardened in a ball shape was confirmed.

(Comparative Example 2) The same lamination as in Example 1 was performed using a non-woven fabric made of polyethylene terephthalate fiber obtained by a usual spunbonding method. Weight 40g / m ² , Tensile strength 9.2kg / 3cm
Was obtained. The filament constituting this nonwoven fabric has a strength of 3.5 g / d, an elongation of 40%, and an elasticity of 100 g / d.
Met. In addition, the softness of the composite structure is just 106 mm,
It was 86 mm wide and had a firm texture. The elastic peelability was peeled twice.

(Comparative Example 3) The same lamination as in Example 1 was carried out using a nonwoven fabric made of polypropylene fibers obtained by a usual spunbonding method. The hardness was just 104 mm, the width was 50 mm, and the texture was firm.
The elastic peelability was peeled three times. (Comparative Example 4) Example 1 using a nonwoven fabric made of nylon 6 fiber obtained by a usual spunbonding method as a nonwoven fabric.
The same lamination was performed. The hardness was 70 mm fresh and 62 mm wide, giving a firm texture. The elastic peeling was performed seven times.

[0035]

The polyester long-fiber nonwoven fabric of the present invention is
Polyester long-fiber non-woven fabric having moderate stretchability, soft feel, uniform basis weight, extremely few yarn breaks, and excellent spinning stability with an extended wiping cycle.
Its elasticity, softness of texture, packaging material for disposable body warmers,
Particularly useful for furoshiki, tablecloths, rugs and the like.

Claims (1)

[Claims] 1. A long-fiber nonwoven fabric made of polytrimethylene terephthalate having an oligomer content of 3 wt% or less, wherein the strength of fibers constituting the nonwoven fabric is 0.7 to 10%.
Polyester long-fiber nonwoven fabric characterized by having an elastic recovery of 4 g / d, an elastic modulus of 15 to 40 g / d, and an elastic recovery at 20% elongation of 70 to 100%.