JPH1060765A - Elastic nonwoven - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a nonwoven fabric which is soft and has no feeling of rubbery feeling, practically usable fabric strength and handleability, and high quality appearance. SOLUTION: In a stretchable nonwoven fabric obtained by a melt-blowing method in which elastic continuous single fibers having an average diameter of 0.1 to 30μ are randomly arranged, the nonwoven fabric contains (a) 2 of the single fibers. Of the single fibers are fused and bonded in parallel with each other, and the length thereof is one of the average diameter of the single fiber.
The linear fused portion in the range of 0 to 1,000 times and (b) the intersection of the linear fused portion and the intersection of the linear fused portion and the single fiber are respectively fused. And (c) there are no more than 400 single-fiber “shrink” portions per unit area of 1 cm ^{2 of the} non-woven fabric, and therefore substantially free from the “shrink” portions. Stretchable nonwoven fabric characterized by having.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stretchable nonwoven fabric made of elastomeric elastic fibers. More specifically, the present invention relates to a stretchable nonwoven fabric having a feeling in which a rubber-like touch inherent in an elastomeric elastic fiber is reduced as much as possible and having practically usable elasticity, stretchability and strength.

[0002]

2. Description of the Related Art Conventionally, the following elastic nonwoven fabrics having both elasticity and elasticity are known.

(1) A polyester elastomer is spun by a spunbond method, a sheet-like material is formed from a group of discharged filaments, and entanglement treatment is performed between the filaments (Japanese Patent Laid-Open No. 57-82553). ).

(2) A polyetherester-based elastomer is spun by a jet spinning method, and a sheet-like material is formed from a group of discharged filaments, and at the same time, intersections (contact points) of the filaments are joined (Japanese Patent Laid-Open No. 5
7-95362).

(3) A block copolyetherester spun by a melt blow method to form a sheet from the discharged filaments (Japanese Patent Laid-Open No. 60-239).
553, U.S. Pat. Nos. 4,910,064 and 4,803,117).

[0006] In the elastic nonwoven fabric described above, since the constituent filaments are originally made of an elastomer exhibiting rubber-like elasticity, the following disadvantages remain unsolved.

[0007] Since the nonwoven fabric itself is composed of filaments exhibiting rubber-like elasticity, the "rubber-like feeling" which is detested by the hand
Is inevitable. Further, "soft feel" is one of the required characteristics. For this purpose, the constituent filaments may be made thinner, but on the other hand, there is a trade-off problem that the breaking strength and elongation of the filaments are extremely reduced and the strength of the nonwoven fabric (fabric strength) described in the following section is insufficient. Occurs.

[0008] Since the breaking strength of the elastic filaments constituting the nonwoven fabric is low, the strength of the nonwoven fabric is not sufficient. In order to increase the strength of the nonwoven fabric, in the above-mentioned technique (1), inter-filament entanglement and fusion treatment of the filament intersection are performed after the fact. However, performing these operations after the formation of the nonwoven fabric not only complicates the process but also causes the fiber length between the contact points to be shortened due to the adhesion of the contact points, which causes a deterioration in the texture of the fabric. .

On the other hand, in the technique (2) described above, self-joining of intersections of filaments at the time of forming a nonwoven fabric (that is, providing a point bonding portion to the nonwoven fabric) is disclosed. It is extremely difficult to obtain a practically usable nonwoven fabric strength.

As can be inferred from the above description, the elastic nonwoven fabric has poor post-handling properties (handling properties). In particular, it is not difficult to imagine the handleability of the products that have not been subjected to the entanglement and fusion (joining) treatments, and even if they are point-bonded, they are not much improved.

Finally, the overall appearance or quality of the nonwoven is given. It is a characteristic required for the quality that the arrangement state of the constituent filaments is uniform and that there is no unnaturalness in appearance.

[0012]

SUMMARY OF THE INVENTION The present invention relates to
As described in the above, the nonwoven fabric that overcomes the trade-offs between the various required properties of an elastic nonwoven fabric, has a soft and rubber-free feeling, a fabric strength and handleability that can be put to practical use, and a dignified appearance Is to provide.

[0013]

According to the study of the present inventors, in order to realize a soft feel to the nonwoven fabric, ultrafine filaments can be spun as compared with the jet spinning method and the spun pond method. The most suitable is a nonwoven fabric by a melt blow method; a decrease in the strength of the nonwoven fabric due to ultra-fine filaments can be prevented by introducing a specific bonding portion (fused portion) specified below into the nonwoven fabric. The presence of the fusion joint minimizes the rubber-like hand of the nonwoven fabric; and the presence of the "shrinkage" portion of the elastic filament as a factor affecting the handleability and quality of the nonwoven fabric. As a result of confirmation by the present inventors, the present invention has been reached.

Thus, according to the present invention, in a stretchable nonwoven fabric obtained by a melt-blowing method, in which elastic continuous single fibers having an average diameter of 0.1 to 30 µ are randomly arranged, the nonwoven fabric contains ( a) Two or more of the single fibers
50 linear fusion parts which are fused and bonded in parallel with each other and whose length is in the range of 10 to 1,000 times the average diameter of the single fiber, and (b) the linear fusion parts And the point-like fusion parts where the intersections of the linear fusion parts and the single fibers are respectively fused are mixed, and (c) the “fine” portion of the single fibers is the unit area of the nonwoven fabric. 400 per cm ²
There is provided a stretchable nonwoven fabric characterized in that there are no more than one, and thus are substantially free of "shrinkage" portions.

Hereinafter, the present invention will be described with reference to the accompanying drawings.

FIG. 1 was obtained by meltblowing.
FIG. 1 is a partially enlarged plan view of a stretchable nonwoven fabric of the present invention, where 1 is an elastic continuous single fiber having a diameter of 0.1 μm to 30 μm (hereinafter, simply referred to as an elastic single fiber or a constituent single fiber) constituting the nonwoven fabric. . As is well known, the elastic monofilaments are randomly arranged to form a stretchable nonwoven fabric. In this case, in this figure, a linear shape is formed by fusing and bonding five elastic monofilaments in parallel. A fused portion 2, a linear fused portion 3 formed by fusing three single fibers, and a point formed by further fusing and joining the two types of linear fused portions 2 and 3 at their intersection. Fused portions 4 and the point-like fused portions 5 formed by fusion and joining of the intersections of the elastic single fibers (both are formed by self-adhesion while the single fibers are cooled after discharge). Is characteristic.

Here, since the point-like fusion portion 4 is larger in size than the point-like fusion portion 5, it may be called a quasi-linear fusion portion in relation to the point-like fusion portion 5. it can.

In the present invention, a non-woven fabric having a desired property is realized by dispersing the above-mentioned linear fusion parts, point fusion parts and quasi-linear fusion parts in the non-woven fabric. However, in this case, it is important that the elastic monofilament and the fused portion further satisfy the following requirements.

The average diameter of the elastic single fiber is 0.1 to 30 μm
The range of the diameter is a range necessary for achieving both the flexibility and the strength of the nonwoven fabric. When the diameter is less than 0.1 μm, the hand feels more flexible but the practicality is lost in terms of strength. I do. On the other hand, when the diameter exceeds 30 μm, although sufficient strength is ensured, a soft feeling is no longer desired. A preferred range for this diameter is 1μ to 20μ. In addition, the diameter mentioned here means that when the cross section of the elastic single fiber is irregular (for example, elliptical, multi-lobed, polygonal, etc.), it is regarded as a round cross section of the corresponding thickness (denier). Also means the diameter of

In the linear fused portion, the elastic single fiber 2
-50 pieces are fused in parallel with each other, and the length thereof is in the range of 10 to 1,000 times the average diameter of the constituent single fibers; This reduces the rubber-like feeling inherent to the nonwoven fabric made of elastic monofilaments and contributes to improving the strength of the nonwoven fabric.

When the number of fused portions is less than 2 (that is, when there are no parallel fused portions) and the length of the fused portion is less than 10 times the average diameter of the constituent single fibers, the rubber-like nonwoven fabric is used. Not only does the feeling disappear, but the strength cannot be improved. On the other hand, if the number of fused portions exceeds 50 or the length of the fused portion exceeds 1,000 times the average diameter of the constituent single fibers, the fused portion becomes too conspicuous and the formation deteriorates, and at the same time, the strength of the nonwoven fabric increases. Also does not improve to the left. The preferred range of the number of fused parts is 5 to 20, and the range of the magnification of the length of the fused part is 50 to 500 times.

The presence of the quasi-linear fused portion 4 and the dotted fused portion 5; such a fused portion contributes to alleviating the rubbery feeling of the nonwoven fabric, Improve the strength, especially the shape retention.

There are no more than 400 "chures" per unit area of 1 cm ^{2 of the} nonwoven fabric.

The "chure" portion is indicated by 6 in FIG. The single fibers constituting the nonwoven fabric are in a linear shape and a gentle curved shape. On the other hand, the “short” portion means that a single fiber or a bundle of single fibers fused in a line is within 5 times the diameter in the fiber axis direction regardless of whether the single fiber is cut or not. The direction of the normal line of the cross section of a single fiber greatly changes at the distance, and refers to the fiber part in a state where the loop is spiral or folded several times in the minute part. A so-called straight portion in which the direction of the normal line of the cross section does not change is a portion having a completely different structure. Then, it was confirmed that the "chubby" portion had an adverse effect on the strength and handleability of the nonwoven fabric.

That is, when the thermoplastic polymer is melt-blown, when the molten polymer is discharged from the die, a high-temperature and high-pressure gas flow used for thinning and pulling the polymer is used.
Single fibers are cut and folded into several layers, resulting in small "chatters". In particular, thermoplastic elastomer has a large melt elasticity, and the above-mentioned "shrinkage" is likely to occur even when the single fiber is not cut. The "shrinkage" portion is a state in which the single fibers are present in a solidified state in a minute area. Then, it has been found that the above-mentioned disadvantage occurs when the number of the above-mentioned “fine” portions exceeds 400 per unit area of the nonwoven fabric.

For this reason, in the present invention, the number of “chubby” portions is suppressed to 400 or less per unit area of 1 cm ^{2 of the} nonwoven fabric. It is particularly preferable that the number of the “chunk” portions is 200 or less.

Further, the above-mentioned linear fusion parts, quasi-linear fusion parts, and point fusion parts will be additionally described.

First, the wire-bonded portion is formed of a unit area 1c of the nonwoven fabric.
It is preferable that the number of single fibers present in the range of 500 to 3,000 per m ² and involved in the wire fusion is in the range of 20 to 100% of the total number of the single fibers constituting the nonwoven fabric. Thereby, the constituent monofilaments have a small diameter but a large elongation,
It is possible to efficiently obtain the same effect as when fibers having a larger diameter are mixed. Unit area of non-woven fabric is 1
When the number is less than 500 per cm ² , the above effect is hardly obtained, and when the number exceeds 3,000, a rubber-like texture is easily developed. A preferred range is 1,000 to 2,500 per unit area of 1 cm ^{2 of the} nonwoven fabric.

Further, the quasi-linear fusion part and the point fusion part are 1,0,0 per unit area of 1 cm ² of the nonwoven fabric.
The presence of 00 to 5,000 pieces is necessary to maintain the fabric strength and stretchability. If less than 1,000,
Good strength and elasticity cannot be maintained. If the number exceeds 5,000, the rubbery feeling is emphasized. A preferred range is from 1,500 to 4,000.

The non-woven fabric of the present invention described above has the following practical elongation recovery characteristics (d) due to its unique structure.
~ (G).

(D) 50% per 100 g / m ^{2 of} basis weight
(E) 30% elongation stress after 50% elongation recovery per 100 g / m ² (e) 50% elongation recovery per 100 g / m ² per unit weight The subsequent 30% recovery stress is 20 to 400 g / cm 2 (g) The 50% elongation elastic recovery is 80% or more and 100% or less The significance of the above characteristics can be explained as follows. That is, the body part using the nonwoven fabric of the present invention, which is protected by a bandage or surgical tape, moves smoothly without any delay, and the bandage or tape follows the movement well, and the movement itself is restricted to some extent. Need to be Therefore, a stretchable nonwoven fabric is required not only to have a sufficient elongation and elastic recovery rate, but also to restrict the movement with an appropriate stress at the time of expansion and contraction and to maintain the shape. In addition, the stretchable nonwoven fabric that is in contact with the above-mentioned portion is required not to be stretched more than necessary at the time of stretching.

Based on the above, the elongation recovery curve of the stretchable nonwoven fabric of the present invention is shown in FIG.

Here, the 50% elongation stress (d) of the nonwoven fabric of the present invention is 100 to 1,000 g / cm. 100
When it is less than g / cm, the nonwoven fabric is too stretched when stretched, making it difficult to use it. On the other hand, when it exceeds 1,000 g / cm, it becomes difficult to stretch itself. The preferred range is 100 to
300 g / cm.

Regarding the subsequent elongation recovery curve of the non-woven fabric once stretched to 50%, there is no significant difference between the stress curve at the time of 50% elongation (ABC) and the recovery stress curve at the time of return, but the 50% elongation recovery curve does not. The elongation stress curve leading to
And C. Accordingly, the 30% elongation stress (e) and the 30% recovery stress (f) are, for example, the repetitive stress when the stretchable nonwoven fabric is stretched by 50% and then returned to 30% elongation when the stretchable nonwoven fabric is attached to the human body, for example. It is an index representing the stress at the time of mounting. The 30% elongation stress (e) is 50 to 500 g / cm, and the 30% recovery stress (f) is 20 to 400 g / cm. If the 30% elongation stress (e) is less than 50 g / cm or the 30% recovery stress (f) is less than 20 g / cm, it tends to shift during mounting,
In addition, sufficient fitting properties and shape retention properties are not exhibited. On the other hand, if the 30% elongation stress (e) exceeds 500 g / cm or the 30% recovery stress (f) exceeds 400 g / cm, the tightening feeling at the time of mounting becomes excessively large. Preferably, at 30% elongation stress (e), 50 to 30
0-2 g at 0 g / cm and 30% recovery stress (f).
00 g / cm.

Further, the nonwoven fabric of the present invention has a 50% elongation elastic recovery (g) of 80% or more and 100% or less. 80%
If it is less than 1, permanent set after recovery from elongation is too large, and the function as a stretchable nonwoven fabric cannot be sufficiently exhibited.

In a further preferred embodiment of the nonwoven fabric of the present invention, in addition to the above characteristic ranges (d) to (g), 3
The ratio of the 30% elongation stress (e) to the 0% recovery stress (f) is 1.2 to 4.0 times in the above stress range.
If the ratio is less than 1.2 times, the values of the elongation stress and the recovery stress are too close to each other and the fit is good, but the feeling of tightening is excessively large. There is a concern that the fit is too large to satisfy the fit.

In order to satisfy the above-mentioned elongation stress characteristics (d) to (g), the apparent density of the nonwoven fabric is also involved. In this sense, the apparent density of the elastic nonwoven fabric is 0.10 g /
It is preferably in the range of cm ³ ~0.45g / cm ^3. When said seal degree is less than 0.1 g / cm ^3, becomes difficult to obtain the tensile stress and recovery stress in the longitudinal and transverse directions both of the non-woven fabric, also exceeds 0.45 g / cm ^3, softness It becomes a rubber-like texture. More preferably, it is 0.15 to 0.35 g / cm ³ .

The stretchable nonwoven fabric of the present invention can be obtained by using a melt blow method. In the melt-blowing method, a molten polymer is usually discharged from a number of spinning holes arranged side by side in the width direction of a die, such as a T-die, and at the same time, a high-temperature, high-speed gas flow is supplied from slits provided on both sides of the die. Is a method of obtaining a sheet-like material by accumulating a group of ultrafine fibers formed by thinning a polymer discharged by jetting on a moving air-permeable collecting surface. According to this method, fine fibers can be easily obtained, and the molten polymer can be directly formed into a sheet. Therefore, the nonwoven fabric of the thermoplastic elastomer can be most preferably obtained.

The yarn-making conditions will be described in more detail. The polymer has a melt viscosity of 100 poise or more and 3,000 or more.
It is not more than poise, more preferably not less than 500 poise and not more than 2,000 poise. If the melt viscosity is too low,
Yarn breakage easily occurs, and at the same time, polymer balls are easily generated, and the uniformity of the fiber diameter also deteriorates. On the other hand, if the melt viscosity is too high, it is difficult to reduce the fiber diameter.

The spinning temperature of the polymer is given by the melting point of the polymer +
(10 ° C. or more and 100 ° C. or less), and it is preferable to lower the viscosity at a temperature as high as possible within a range where the polymer does not thermally decompose and a process condition is stable. If the temperature is too high, the melt viscosity increases, which is not preferable. If the temperature is too high, thermal decomposition is liable to occur, and the long-term operation stability decreases.

In order to obtain a nonwoven fabric having the structure specified in the present invention, the discharge linear velocity (m / min) when the molten polymer is discharged from the spinning hole is 0.5 to 10 m / min, preferably 1 to 10 m / min. Adjusting to ~ 5 m / min has proven useful. The discharge linear velocity (m / min) can be obtained from the discharge area (cm ² ) of the spinning hole and the discharge amount per single hole (cc / min) by the following formula.

Discharge linear velocity (m / min) = discharge amount per single hole / discharge area / 100 The high-temperature and high-pressure gas for drawing and thinning the discharged polymer is preferably air or water vapor. If the temperature of the traction gas is too far from the spinning temperature of the polymer, it will affect the temperature of the discharged polymer.
10 ° C] or more and [the melting point of the polymer + 100 ° C] or less, more preferably [the spinning temperature of the polymer + 10 to 50 ° C]. Further, the gas flow rate may be appropriately determined depending on the target fiber diameter, the discharge amount, and the bonding state. At this time, although it depends on the jet slit width of the gas flow, the preferable flow rate is the die width 1.
It is 0.01 to 0.2 Nm ³ / min per cm. 0.0
If it is less than 1 Nm ³ / min, the thinning does not proceed sufficiently, and the unevenness of the obtained nonwoven fabric also becomes large. If it exceeds 0.2 Nm ³ / min, the fiber breaks excessively due to the width of the slit and the discharge amount, and it does not cut. Even so, a large number of "fine" portions are generated, which is not preferable.

The group of fibers discharged and drawn by the high-temperature and high-pressure gas is deposited on a collecting surface such as a net having a suction, and is obtained as a sheet-like material, that is, a nonwoven fabric. In this case, by setting the distance between the lower surface of the base and the collecting surface to be lower than the position where the fibers are solidified, the fibers do not adhere to each other more than necessary in the above-mentioned fused and bonded state, and the texture of the nonwoven fabric does not become coarse and hard. Is preferred. If the collecting surface is located too low, the fiber flow will be disturbed by the jet gas flow and the accompanying flow, and the fibers will be entangled in a bundle, causing nonwoven spots. The preferred distance is between 10 and 80 cm.

The thermoplastic elastomer constituting the stretchable nonwoven fabric of the present invention is not particularly limited as long as it has rubber elasticity, such as polyurethane, polyester-based elastomer and polyolefin-based elastomer. From the viewpoint of light resistance and yellowing resistance after fabric formation, polyester-based elastomers are preferred.

As the polyester-based elastomer, a block copolymer comprising a polyester hard segment having crystallinity and a flexible soft segment comprising at least one selected from polyether or polyester is generally used.

In the polyester constituting the hard segment, 50 mol% or more, preferably 70 mol% or more of the acid component is terephthalic acid or an ester-forming derivative thereof, and 50 mol% or more, preferably 70 mol% or more of the diol component. Polybutylene terephthalate-based polyester obtained by polycondensation of component units that are 1,4-butanediol or its ester-forming derivative is preferably used because of its high crystallization rate. That is, the hard segment is preferably a crystalline aromatic polyester segment.

The dicarboxylic acids other than terephthalic acid include isophthalic acid, 2,6-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid, and 4,4'-diphenyldicarboxylic acid. , Adipic acid and the like.
Examples of diols other than -butanediol include ethylene glycol, trimethylene glycol, neopentyl glycol, 1,5-pentanediol, 1,6-hexanediol, and 1,4-cyclohexanedimethanol. Such an acid component and a diol component may be used alone or in combination, but at that time, the crystalline polyester constituting the hard segment has an intrinsic viscosity of 0.6 to 2.0 and a melting point of 120.
It is important that the temperature is not lower than ℃ (preferably not lower than 150 ° C) and not higher than 280 ° C (preferably not higher than 220 ° C). When the intrinsic viscosity is less than 0.6, the melt-moldability of the obtained copolymerized polyester is significantly reduced, and the performance as a nonwoven fabric is also deteriorated. Conversely, if the intrinsic viscosity exceeds 2.0, the melt-kneading temperature must be set high during the production of the copolymerized polyester, which is not preferable from the viewpoint of thermal degradation of the polyester. On the other hand, regarding the melting point, the soft segment is made of a polyetherester in which the diol component is a polyalkylene glycol or a flexible polyester described later.

As the polyalkylene glycol, polyalkylene oxide glycols such as polyethylene glycol, polybutylene glycol and polypropylene glycol are preferably used, and these can be used alone or in combination. Its molecular weight (number average)
Is preferably in the range of 300 to 10,000, but is preferably 50 in view of the elasticity of the fiber and the heat resistance during molding.
Those having 0 to 5,000 are preferred.

As the acid component of the polyetherester, the dicarboxylic acid used for forming the above-mentioned hard segment may be used.

At that time, the proportion of the polyalkylene glycol in the finally obtained polyetherester type block copolymer elastomer is 30 to 90% by weight, preferably 40 to 80% by weight, more preferably 50 to 80% by weight.
When the content is within the range of 70 to 70% by weight, the balance between the elastic recovery rate of the nonwoven fabric, the 50% elongation stress, the 30% elongation stress and the recovery stress, and the moldability are compatible.

The above-mentioned polyetherester type block copolymer elastomer can be obtained by a method well known in the art, that is, by transesterifying a dicarboxylic acid derivative, an alkylene diol, or a polyalkylene diol, followed by a polymerization reaction. it can.

On the other hand, when a polyester ester block copolymer using a soft polyester as a soft segment is used as the nonwoven fabric raw material polymer, the polyester constituting the soft component is a polycaprolactone-based aliphatic polyester or the following (I) Polyesters which simultaneously satisfy the requirements of (1) to (III) are preferably used.

(I) The aliphatic dicarboxylic acid component having 4 to 20 carbon atoms occupies 0 to 50 mol% based on the total acid component of the polyester constituting the soft segment.

(II) The aromatic dicarboxylic acid component having 8 to 16 carbon atoms occupies 50 to 100 mol% based on the total acid component of the polyester constituting the soft segment.

(III) The aliphatic diol compound having 3 to 20 carbon atoms occupies 50 to 100 mol% based on all diol components of the polyester constituting the soft segment.

Here, when the number of carbon atoms of the aliphatic dicarboxylic acid component (I) is less than 4, the number of carbon atoms existing between carboxyl groups is small, so that the obtained block copolymerized polyester is susceptible to hydrolysis, Further, the thermal stability during melt spinning is poor. Conversely, if the number of carbon atoms exceeds 20, the aliphatic dicarboxylic acid is expensive and difficult to obtain. The preferred number of carbon atoms is 7 to 15. Examples of the aliphatic dicarboxylic acid that can be preferably used include azelaic acid, sebacic acid, and decane dicarboxylic acid. These may be used alone or in combination of two or more.

The copolymerization amount of the above-mentioned aliphatic dicarboxylic acid is as follows:
0 to 50 mol% based on the total acid component of the polyester constituting the soft segment, but the copolymerization ratio is 5 to 3 from the viewpoint of heat resistance of the obtained block copolymerized polyester.
It is preferably 0 mol%.

Next, the (II) aromatic dicarboxylic acid component having 8 to 16 carbon atoms accounts for 50 to 100 mol%, preferably 70 to 95 mol%, based on the total acid component of the polyester constituting the soft segment. Occupancy is preferred. This aromatic dicarboxylic acid component, without reducing the hydrolysis resistance of the soft segment polyester, heat resistance, in order to function as a soft segment in the obtained block copolymerized polyester, for the purpose of reducing the crystallinity described above. Must occupy an amount. Such aromatic dicarboxylic acid components include terephthalic acid, isophthalic acid, phthalic acid, 2,6-naphthalenedicarboxylic acid,
Diphenyldicarboxylic acid and the like are preferred.

The aliphatic diol compound (III) having 3 to 20 carbon atoms preferably accounts for 50 to 100 mol% based on all diol components of the polyester constituting the soft segment. If the number of carbon atoms is less than 3, the number of repeating structural units per unit weight increases, and the hydrolysis resistance is poor. Conversely, when the carbon number exceeds 20, the reactivity is lacking. When the amount of the aliphatic diol component is less than 50 mol%, the flexibility of the (co) polymerized polyester becomes insufficient.

Such diol compounds include propylene glycol, tetramethylene glycol, 1,5
-Pentanediol, 3-methyl-1,5-pentanediol, neopentyl glycol, trimethylpentanediol, 1,6-hexanediol, 1,4-cyclohexanedimethanol, 1,9-nonanediol, eicosandiol, Ethylene glycol can be mentioned. Among them, those having an alkyl group in a side chain are particularly preferable in order to reduce the crystallinity of the soft segment. Of course, the above diol compounds may be used alone or in combination of two or more.

The intrinsic viscosity of the polyester alone constituting the soft segment is preferably in the range of 0.6 to 1.0. When the intrinsic viscosity is less than 0.6, the melt-moldability of the obtained block copolymerized polyester is significantly reduced, and the performance as a nonwoven fabric is further deteriorated. Conversely, if the intrinsic viscosity exceeds 1.0, the melt-kneading temperature must be set high during the production of the block copolymerized polyester, which is not preferable from the viewpoint of thermal degradation of the polymer.

This type of polyester ester type block copolymer elastomer can be obtained by melt-kneading the above-mentioned polyester constituting the hard segment and the polyester constituting the soft segment and subjecting them to a blocking reaction. At this time, the respective copolymerization ratios (weight ratios) in the blocking reaction were defined as (polyester constituting the hard segment) :( polyester constituting the soft segment) = (10-70) :( 9
0 to 30). When the copolymerization ratio of the polyester constituting the hard segment is less than 10% by weight, the amount of the hard segment in the obtained block copolymerized polyester is too small, and the heat resistance, molding processability, workability during nonwoven fabric production, etc. are reduced. In addition, the elongation stress of the nonwoven fabric becomes insufficient. Conversely, if it exceeds 90% by weight, the elongation elastic recovery of the block copolymerized polyester becomes insufficient. The blocking reaction may be performed by any of a batch method and a continuous method. For example, a method in which each polyester component is individually subjected to a polycondensation reaction to a desired intrinsic viscosity, and then mixed to perform a blocking reaction. Can be mentioned.

Of course, the elastomer may contain a flame retardant and, if desired, additives such as a chain extender, a filler, an antioxidant and a lubricant.

[0064]

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited thereto.

In the examples, "parts" indicates parts by weight,
Each physical property value was measured using the following method.

(1) Average Single Fiber Diameter The diameter of 100 single fibers is calculated from the cross-section of the nonwoven fabric from an electron micrograph of × 500 and calculated by averaging.

(2) The number of fused single fibers, the length and number of linearly fused portions, the number of dot-like fused portions, and the number of spots in the linearly fused portion. From the electron micrograph, the number of fused single fibers in the linear fused portion was determined. The length of the linear fused portion was also determined, and the magnification with respect to the average single fiber diameter was calculated. Further, for an area of 4.8 mm ² , the number m of the linear fusion parts, the number of the point fusion parts, and the number of the torn parts were determined to obtain 1c.
It was converted into the number per m ^{2, and} the ratio of the linearly fused portion was calculated by the following formula as the number of single fibers involved in the linear fusion with respect to the total number n of the single fibers.

(3) 50% elongation stress per unit weight of 100 g / m ² (d) Longitudinal direction (flow direction of collection net) and width of nonwoven fabric The 50% elongation stress in the direction (width direction of the collecting net) was measured as follows.

After forming a rectangular sample piece having a length of 8 cm and a width of 2.5 cm from the nonwoven fabric, a short piece of two opposing sides is gripped with a chuck, and the distance between the chucks is reduced by 5 mm.
and cm, the stress when the original chuck distance is extended 50%, based at extension rate of 200% / min and X1, as stress per short sides 1cm relative basis weight Yg / m ² nonwoven fabric, the following equation Was calculated by

50% elongation stress per unit weight of 100 g / m ² (g / cm) = X1 / Y × 100 (4) 30% elongation stress after recovery of 50% elongation per unit weight of 100 g / m ² (e) Cut vertically or horizontally as the long side of the rectangle to a length of 8 cm and a width of 2.5 cm.
The sample was stretched by 50% with respect to the sample length at a stretching speed of 200% / min in the direction of the long side as m, and immediately returned to the original chuck interval at the same speed. Extension rate as fast at is extended again nonwoven fabric, a stress when elongation was 30%, based on the original chuck interval is X2, as stress per short sides 1cm relative basis weight Yg / m ² nonwoven fabric, It was calculated by the following equation.

30% elongation stress (g / cm) after 50% elongation recovery per 100 g / m ² = X2 / Y × 100 (5) 30% recovery after 50% elongation recovery per 100 g / m ² Stress (f) Cut the non-woven fabric in the vertical or horizontal direction as the long side of the rectangle to a length of 8 cm and a width of 2.5 cm, and set the chuck interval at 5 c.
The sample was stretched by 50% with respect to the sample length at a stretching speed of 200% / min in the direction of the long side as m, and immediately returned to the original chuck interval at the same speed. The nonwoven fabric is stretched again at the same speed as the stretching speed by 30% based on the original chuck interval, and then immediately returned at the same speed without maintaining the state, and stretched by 30% based on the original chuck interval. The stress at the time of recovery to X3 was defined as X3, and the stress per 1 cm of the short side with respect to the basis weight Yg / m ² of the nonwoven fabric was calculated by the following equation.

30% recovery stress (g / cm) after 50% elongation recovery per unit weight of 100 g / m ² = X3 / Y × 100 (6) 50% elongation elastic recovery rate (g) Long side with chuck interval of 5 cm Extension speed in the direction of 20
After elongating 50% with respect to the sample length at 0% / min, and setting the interval as the sample length L (7.5 cm), hold the original chuck at the same speed as the elongation speed without maintaining the interval, and Back up. Immediately after that, the nonwoven fabric is stretched again,
The sample length when the stress starts to become larger than 0 is L'c
m was calculated by the following equation.

50% elongation elastic recovery (%) = (L−
L ′) / (L−5) × 100 (7) Apparent density Calculated from the basis weight and thickness of the obtained nonwoven fabric.

[Example 1] Dimethyl terephthalate 167
Parts by weight, 105 parts by weight of tetramethylene glycol, polytetramethylene glycol 32 having a number average molecular weight of 2,000
After the transesterification reaction of 5 parts by weight in the reactor, the internal temperature was raised to 245 ° C., the reaction was carried out for 60 minutes under a weak vacuum of 20 mmaq, and then 200 hours under a high vacuum of 0.4 mmaq.
Allowed to react for minutes. The obtained block copolymer of polyester and polyetherester had a melting point of 190 ° C. and an intrinsic viscosity of 1.52.

The copolymer was heated at 115 ° C. under a reduced pressure of 1 mmHg.
For 16 hours and melted at 260 ° C. by a melt blow method, and then a discharge line speed of 1.7 m is used using a die having a circular cross section and discharge holes arranged in a single row at intervals of 1 mm in the width direction of the die.
After discharging at a rate of 0.06 Nm ³ / min, the discharge polyester is stretched and thinned, and then the compressed air is heated to 300 ° C. at a rate of 0.06 Nm ³ / min.
It was collected as a nonwoven fabric having a basis weight of 100 g / m ² on a collecting net provided below and running at 1.2 m / min.

The average single fiber diameter of the obtained nonwoven fabric was 7 μm, the apparent density of the nonwoven fabric was 0.19 g / cm ³ , and the thickness was 0.3.
mm, and the length of the linear fused portion is fused at a distance of 70 μm or more in a range of 2 or more and 50 or less,
It contains 55% of the total number of single fibers.
Three to eight were overwhelmingly large. The number of linear fusion parts per unit area 1 cm ^{2 of the} nonwoven fabric is 1,500, the number of point fusion parts is 2,300, and the number of shrinkage parts is 210,
It is a soft-textured non-woven fabric with no rubbery feeling.

The 50% elongation stress (d), the 30% elongation stress after 50% elongation recovery and the recovery stress of the obtained nonwoven fabric were 256/160 g / h in the longitudinal / horizontal directions, respectively.
cm, 144/88 g / cm, 112/64 g / cm
And the 50% elastic recovery (g) is 89/89%,
It showed good elastic recovery in both the longitudinal and transverse directions, and could be suitably used as a stretchable nonwoven fabric having appropriate elongation stress and recovery stress. (E) / (f) was 1.8 / 1.4 in the vertical / horizontal directions.

Further, this non-woven fabric was made up and down with a diameter of 200 mmφ.
Using chrome-plated flat rollers, calendering was performed at a roller temperature of 160 ° C. and a clearance between rollers of 0.25 mm at a speed of 2 m / min.
cm, 480%, and the 50% elongation stress, the 30% elongation stress after 50% elongation recovery and the recovery stress are 272/152 g / cm and 140/88 g in the longitudinal / lateral directions, respectively.
/ Cm, 116/66 g / cm, and a 50% elastic recovery was 98/97%. This non-woven fabric is 3c in width
When cut into a long and narrow band and used as a bandage, it was found to be excellent in moderate tightness and fit.

Comparative Example 1 Using the polymer of Example 1, a nonwoven fabric having a basis weight of 100 g / m ² was obtained by a melt blow method. At this time, the discharge linear velocity of the polymer was 12.2 m.
/ Min, and the compressed air flow rate is 0.15 Nm / cm
The procedure was performed in the same manner as in Example 1 except that the rate was ³ / min. The average single fiber diameter of the obtained nonwoven fabric was 15 μm, the apparent density of the nonwoven fabric was 0.18 g / cm ³ , the thickness was 0.3 mm,
70% of the total number of single fibers are fused in a range of 2 to 50 fibers at a distance of 150 microns or more along the fiber axis direction. Most of them were ten. The number of wire fusion parts per unit area of 1 cm ^{2 of the} nonwoven fabric is 4,000, and the number of point fusion parts is 5,5.
In addition to 00, the number of small portions was 780, far exceeding the upper limit of the present invention, and there were many surface irregularities.

The 50% elongation stress (d), the 30% elongation stress after 50% elongation recovery and the recovery stress (e) and (f) of the obtained nonwoven fabric were respectively in the longitudinal / horizontal directions.
220/160 g / cm, 110/63 g / cm, 98
/ 55 g / cm, the 50% elongation elastic recovery (g) is 9
0/88%. (E) / (f) was 1.1 / 1.1 in the vertical / horizontal direction.

Further, when the nonwoven fabric was calendered in the same manner as in Example 1, the nonwoven fabric had a 50% breaking stress,
The 30% elongation stress and the recovery stress after the 0% elongation recovery were 295/182 g / cm and 13
A nonwoven fabric of 8/92 g / cm and 109/63 g / cm and a 50% elastic recovery rate of 97/95% was obtained, but the nonwoven fabric had large spots and a portion fused to the roller was formed.

Table 1 shows the numbers of the linear fusion parts, the point fusion parts, and the broken parts with respect to the respective ejection linear velocities when the polymers of the examples were used.

[0083]

[Table 1]

Those having a discharge linear velocity in the range of 0.5 to 10 m / min have the characteristics of the non-woven fabric of the present invention. , The texture was not good.

Example 2 Dimethyl Terephthalate 194
Parts by weight, 162 parts by weight of tetramethylene glycol, and 0.15 part by weight of titanium tetrabutoxide were charged into a transesterification reactor, and the temperature was increased to 190 ° C. under a nitrogen gas atmosphere. An exchange reaction was performed.

After completion of the transesterification, 230
C., polycondensation reaction, intrinsic viscosity 1.07, melting point 223
Thus, a polybutylene terephthalate-based polyester polymer at a temperature of ° C was obtained.

On the other hand, 136 parts by weight of dimethyl isophthalate, 62 parts by weight of dimethyl sebacate, and 180 parts by weight of 1,6-hexanediol were mixed with 0.1 part of dibutyltin acetate.
The mixture was heated together with 3 parts by weight to remove by-product methanol from the reaction system. The reaction product is transferred to a reaction vessel capable of
The reaction was carried out at 55 ° C. under reduced pressure to obtain an amorphous polyester having an intrinsic viscosity of 0.80.

The above-mentioned polybutylene terephthalate-based polyester and this amorphous polyester were mixed in a weight ratio of 35:65.
And reduced pressure of 1 mmHg.
After reaction at 0 ° C. for 50 minutes, 0.2 part by weight of phenylphosphonic acid was added as a catalyst deactivator, and the mixture was further stirred for 10 minutes to completely stop the block reaction. The intrinsic viscosity of the obtained polyester ester block copolymer was 1.15 and the melting point was 205 ° C.

The copolymer was heated at 120 ° C. under a reduced pressure of 1 mmHg.
And melted at 270 ° C. by a melt blow method. After discharging under the same conditions as in Example 1, the polyester is stretched and thinned by a pressurized air heated to 300 ° C., and then placed on a collecting net. It was collected as a nonwoven fabric having a basis weight of 100 g / m ² .

The average single fiber diameter of the obtained nonwoven fabric was 8 μm, the apparent density of the nonwoven fabric was 0.20 g / cm ³ , and the thickness was 0.3.
mm, and the percentage of single fibers fused together at a distance of 100 microns or more along the fiber axis direction among the single fibers constituting the fabric was 78%. The number of fused pieces was 8 to 12 pieces in most cases. The number of linear fusion parts per unit area of 1 cm ^{2 of the} nonwoven fabric is 2,000, the number of point fusion parts is 2,100, and the number of shrinkage parts is 70,
It had a soft texture without a feeling of rubber. In addition, (e) / (f) was 1.5 / 1.5 in length / width.

The 50% elongation stress (d), the 30% elongation stress after 50% elongation recovery, and the recovery stress (e) and (f) of the obtained nonwoven fabric were as follows:
220/132 g / cm, 99/56 g / cm, 66 /
At 38 g / cm, the 50% elastic recovery (g) is 94/9
It was 5%, showing a good elastic recovery rate in both the vertical and horizontal directions, and could be suitably used as a stretchable nonwoven fabric having an appropriate elongation stress and recovery stress.

[0092]

The stretchable nonwoven fabric of the present invention has the softness exhibited by the small diameter single fiber, and the good quality and handleability due to the absence of the torn portion. By mixing the fused / bonded wire fusion parts and the point fusion parts fused at their intersections, the rubber-like feeling disappears and has good stress and elastic recovery during elongation. . Therefore, it has a well-balanced stretch characteristic and can be suitably used for clothing and medical use.

[Brief description of the drawings]

FIG. 1 is a partially enlarged plan view of a stretchable nonwoven fabric according to the present invention, which is traced from an electron micrograph (× 50) of the stretchable nonwoven fabric obtained in Example 1 of the present invention.

FIG. 2 is an elongation stress graph illustrating the elongation stress behavior of the stretchable nonwoven fabric according to the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Elastic continuous single fiber which comprises an elastic nonwoven fabric 2, 3 Linear fusion part 4 Point fusion part (quasi-linear fusion part) where the intersection of linear fusion parts 2 and 3 was fused 5 points -Shaped fusion part 6 "Chure" part of single fiber

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Toshimasa Kuroda 3-4-1, Amihara, Ibaraki-shi, Osaka Teijin Limited Osaka Research Center

Claims (11)

[Claims] 1. A stretchable nonwoven fabric obtained by a melt-blowing method in which elastic continuous monofilaments having an average diameter of 0.1 to 30 μ are randomly arranged. Two to fifty fibers are fused and bonded in parallel with each other, and the length thereof is one of the average diameter of the single fiber.
The linear fused portion in the range of 0 to 1,000 times and (b) the intersection of the linear fused portion and the intersection of the linear fused portion and the single fiber are respectively fused. And (c) there are no more than 400 single-fiber “shrink” portions per unit area of 1 cm ^{2 of the} non-woven fabric, and therefore substantially free from the “shrink” portions. Stretchable nonwoven fabric characterized by having. 2. The stretchable nonwoven fabric according to claim 1, wherein the linear fused portion is formed by fusing 5 to 20 single fibers. 3. The length of the linear fused portion is in the range of 50 to 500 times the average diameter of the single fiber.
Stretch nonwoven. 4. The non-woven fabric has a unit area of 1 cm ^2,
The stretchable nonwoven fabric according to claim 1, wherein the number of the stretchable nonwoven fabric is 500 to 3,000 pieces. 5. The stretchable nonwoven fabric according to claim 1, wherein the number of single fibers involved in the linear fused portion is in the range of 20% to 100% of the total number of single fibers constituting the nonwoven fabric. 6. The nonwoven fabric has a point-like fused portion having a unit area of 1 cm ^2.
The stretchable nonwoven fabric according to claim 1, wherein the number of the stretchable nonwoven fabrics is 500 to 5,000. 7. The stretchable nonwoven fabric according to claim 1, wherein the number of single fibers involved in the point-like fused portion is in the range of 20% to 100% of the total number of single fibers constituting the nonwoven fabric. 8. The stretchable nonwoven fabric according to claim 1, which simultaneously satisfies the following elongation characteristics (d) to (g). (D) 50% elongation stress per unit weight of 100 g / m ² is 1
(E) 30% elongation stress after 50% elongation recovery per 100 g / m ² (f) 30% elongation stress after 50% elongation recovery per 100 g / m ² per unit weight. % Recovery stress is 20 to 400 g / cm 2 (g) 50% elongation elastic recovery is 80% or more and 100% or less 9. Elongation stress (e) / recovery stress (f) is 1.
The stretchable nonwoven fabric according to claim 8, which is in a range of 2 to 4.0. 10. The nonwoven fabric has an apparent density of 0.1 g / cm ^3.
Stretchable nonwoven fabric according to any one of claims 9-10 in the range of ~0.45g / cm ³ 11. The stretchable nonwoven fabric according to claim 1, wherein the elastic single fiber is made of a thermoplastic elastomer containing a polyester block copolymer as a main component.