JP2940834B2 - Stretchable nonwoven fabric 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 non-woven fabric having excellent elasticity, which can be suitably used for a medical base fabric, a core material for sports clothing, supporters, various belt materials, a base fabric for artificial leather, and the like. It relates to a manufacturing method.

[0002]

2. Description of the Related Art Conventionally, as a nonwoven fabric which can be suitably used as a batting or the like for sports clothing, a short fiber web composed of an inelastic fiber is provided on at least one surface of a long fiber fleece formed by accumulating polyurethane elastic long fibers. Are laminated, and this laminate is integrated by needling (JP-A-60-146004). This non-woven fabric
Since it has both elasticity by the long fiber web and heat insulation by the short fiber web, it is particularly suitable as batting.

However, in this nonwoven fabric, the elasticity of the long fiber fleece is suppressed by the short fiber web, and it has been difficult to impart a high degree of elasticity. Further, when the nonwoven fabric is repeatedly expanded and contracted, there is a disadvantage that the inelastic fibers constituting the short fiber web fall off.

[0004]

SUMMARY OF THE INVENTION Therefore, the present invention provides a short fiber web having a special form so as not to suppress the stretchability of the long fiber fleece, and The fiber constituting the short fiber web is made difficult to fall off even after repeated expansion and contraction.

[0005]

That is, the present invention is directed to a short fiber web in which short fibers having a spiral crimp are accumulated on at least one surface of a long fiber fleece in which polyurethane elastic long fibers are accumulated. Laminated, the short fibers are
The present invention relates to a stretchable nonwoven fabric characterized by penetrating between the polyurethane elastic long fibers of the long fiber fleece and intertwining the short fibers with each other by needling, and a method for producing the same.

The polyurethane elastic filaments used in the present invention are obtained by melt-spinning a polyurethane copolymer synthesized from a polyol, an organic diisocyanate and a chain extender. Polyols used for synthesizing the polyurethane copolymer include polyethylene glycol, polytetramethylene glycol, poly-ε-caprolactone, polybutylene adipate, dihydroxypolyether, dihydroxypolyester, dihydroxypolycarbonate, and dihydroxypolyesteramide. 500-6000 low melting point polyols are used. In particular, when polyethylene glycol is used, the hydrophilicity of the obtained polyurethane copolymer tends to be improved. Examples of the organic diisocyanate include P, P'-diphenylmethane diisocyanate, tolylene diisocyanate,
Isophorone diisocyanate, hydrogenated diphenylmethane diisocyanate, xylylene diisocyanate, 2,6-
Diisocyanate methylcaproate, hexamethylene diisocyanate and the like are used. In particular, P, P'-diphenylmethane diisocyanate is preferably used. As the chain extender, 1,4-bishydroxyethoxybenzene or 1,4-butanediol can be suitably used. In addition, various glycols with a molecular weight of 500 or less, various amino alcohols,
Various triols can also be used as chain extenders. The mixing ratio of the polyol, the organic diisocyanate, and the chain extender is arbitrary, but it is particularly preferable to mix the polyol component at 65% by weight or more, more preferably 68% by weight or more. If the polyol component is less than 65% by weight, the resulting polyurethane elastic filaments tend to have a lower elongation or elongation recovery.

[0007] The above polyurethane copolymer is melt-spun to obtain polyurethane elastic filaments. The fiber diameter of the polyurethane elastic long fiber is preferably 50 μm or less, and is generally about 30 μm or less on average. The average is particularly preferably 25 μm or less, more preferably 20 μm or less. The average fiber diameter is 50
If it exceeds μ, the flexibility of the obtained long-fiber fleece tends to decrease. The cross-sectional shape of the polyurethane elastic long fiber may be any shape such as a circle, an irregular shape, and a hollow shape. However, if the formability of the long fiber fleece or the post-processability or stretchability of the long fiber fleece is considered, It is preferable to adopt a circular cross section.

Then, the polyurethane elastic filaments are opened and accumulated, and bonded by any means between the polyurethane elastic filaments to obtain a long fiber fleece. The general method of opening and accumulating polyurethane elastic filaments is to melt and spin the polyurethane copolymer while entraining the polyurethane elastic filaments in a high-speed air flow, pulling them down, and then drawing the polyurethane elastic filaments. This is a method in which the fibers are collected on a belt conveyor while spreading. As another method, a method of once obtaining polyurethane elastic filaments, opening the polyurethane elastic filaments by a wet method, a charging method or the like, and accumulating them on a conveyor or the like. In addition, as a general method of bonding between the polyurethane elastic filaments, the polyurethane elastic filaments are accumulated in a state where they are still melted or softened, and then the polyurethane elastic filaments are solidified. This is a method of self-bonding the spaces.
Another method is to apply heat and pressure to the solidified polyurethane elastic filaments to soften or melt them, and then to solidify again. There is a method in which an adhesive or the like is applied between the fibers to bond the long fibers to each other.

The long-fiber fleece obtained as described above generally has an expansion and contraction ratio of 40% or more in both the warp direction and the weft direction. In particular, polyurethane elastic filaments which are excellent in elasticity are used, and those in which long filaments are connected to each other by self-fusion of polyurethane elastic filaments have an elasticity of 70% or more. Here, the expansion ratio is
A strip-shaped sample having a width of 2.5 cm and a length of 10 cm is collected from a long fiber fleece, stretched in the length direction, and measured by the following method. That is, the initial sample length is L ₀ ,
The length after applying an arbitrary load to this sample and extending it is L ₁
Then, remove the load and measure the length after the sample shrinks.
If the L _2, when the maximum value of L ₁ in the case of satisfying L ₂ ≦ 1.1 L ₀ was L _11, expansion ratio _{X% = [(L 11 -L} 0) /
L ₀ ] × 100. Also, the basis weight of the long fiber fleece used in the present invention is generally 10 to 300 g.
/ M ² . As such a long-fiber fleece, a commercially available product, "Espansione" manufactured by Kanebo Co., Ltd. can be suitably used.

A short fiber web is laminated on at least one side of the long fiber fleece described above. This short fiber web is formed by accumulating short fibers having a spiral crimp.
A short fiber having a fiber length of about 20 to 200 mm is used. The denier of the short fiber is about 1 to 10 denier. Short fiber materials include polyolefin fibers, polyamide fibers, polyester fibers,
Polyacrylonitrile fiber or the like is used. The short fiber used in the present invention has a spiral crimp. The number of turns of the helix is preferably 5 or more over the entire length of the short fiber.

The short fiber web can be obtained by spreading and accumulating short fibers by a card method, an Undam Weber method, an air opening method or the like. In particular, it is preferable to use a random web in which short fibers are randomly (randomly) accumulated. This is because it is easy to show the same elasticity in any direction. Further, the short fibers of the short fiber web are not bonded with an adhesive or the like as in the case of the long fiber fleece. The basis weight of the short fiber web is preferably about 10 to 300 g / m ² .

The short fibers constituting the short fiber web penetrate between the polyurethane elastic long fibers of the long fiber fleece by needling. Needling is performed by piercing a laminate of short fiber web and long fiber fleece with a barbed needle. The operation of this needling will be described below with reference to FIG. That is,
When a barbed needle (not shown) is pierced through the laminates 1 and 2, first, the short fibers 4 in the short fiber web 1 are gripped by the barbs. Then, as it is, the needle penetrates the long fiber fleece 2, so that the short fiber 4 comes out on the back side of the long fiber fleece 2. Thereafter, when the needle is pulled out of the long fiber fleece 2, the short fibers 4 held by the spines remain on the back side of the long fiber fleece 2, and eventually the short fibers 4 penetrate between the polyurethane elastic long fibers 3 of the long fiber fleece 2. It is. When the barbed needle penetrates the long fiber fleece 2, the gap between the polyurethane elastic long fibers 3 constituting the long fiber fleece 2 is expanded. This is due to the elasticity of the polyurethane elastic filaments 3. Then, when the barbed needle is pulled out from the long fiber fleece 2,
The gap between the expanded polyurethane elastic long fibers 3 is reduced. This is also due to the elasticity of the polyurethane elastic long fibers 3. Therefore, the penetrating short fiber 4 is firmly gripped by the long fiber fleece 2 by the expansion and contraction of the gap between the polyurethane elastic long fibers 3. In addition, the short fibers 4 that have penetrated and come out on the back side of the long fiber fleece 2 are:
It has a spiral crimp. Therefore, it is less likely to fall off from the long fiber fleece 2 as compared to the linear short fiber having no crimp. Furthermore, polyurethane elastic filaments 3
Has tackiness based on the properties of the polyurethane copolymer. Therefore, the polyurethane elastic filaments 3
The short fibers 4 that are in contact with the long fiber fleece 2 are more firmly gripped by the long fiber fleece 2. Further, the short fibers 4 in the short fiber web 1 are entangled with each other by needling.

As described above, the stretchable nonwoven fabric according to the present invention has a structure as shown in FIG. The stretchable nonwoven fabric having such a configuration can easily have its stretch ratio at least 30%, preferably at least 50%. For example,
Only a short fiber web obtained by accumulating short fibers having a spiral crimp, a nonwoven fabric obtained by entanglement by needling,
It is difficult to make the expansion ratio 30% or more. That is, although such a nonwoven fabric can obtain a certain degree of elongation,
When the load is removed, the shrinkage ratio is small.
That's less than 30%. This is because there is no long fiber fleece with high elasticity. Here, the stretch ratio is measured in the same manner as the stretch ratio of the long fiber fleece described above.

Further, the elastic nonwoven fabric according to the present invention can easily reduce the residual strain to 30% or less. For example,
Only a short fiber web obtained by accumulating short fibers having a spiral crimp, a nonwoven fabric obtained by entanglement by needling,
It is difficult to reduce the residual strain to 40% or less. That is, although such a nonwoven fabric can obtain a certain degree of elongation,
This is because the contraction rate when the load is removed is small. Here, the residual strain is represented by an elongation (%) when measured by the following method. That is, a strip sample having a width of 2.5 cm and a length of 10 cm is collected from a stretchable nonwoven fabric, and stretched at a stretching speed of 10 cm / min in a length direction at a gripping interval of 5 cm until the length reaches 200% of the original length, Subsequently, the operation of immediately returning to the original length is repeated five times, and is expressed by the elongation (%) in the longitudinal direction of the sample.

The most preferred constitution of the stretchable nonwoven fabric according to the present invention is the stretchable nonwoven fabric described in claim 1, which satisfies the following formulas (1) and (2). Note L (mm)> N (mm) ... (1) [T (times) / L (mm)]> [1 / N (mm)] ... (2) (However, N (mm) is The maximum value of the distance between adjacent needling marks is represented, L (mm) represents the length of short fibers, and T
(Times) represents the number of turns over the entire length (L) of the short fiber. If the formula (1) is not satisfied, that is, if the fiber length of the short fiber 4 is shorter than the distance between the adjacent needling marks 5, 5, both ends of the short fiber 4 are not gripped by the long fiber fleece 3, and the short fiber 4 tends to fall off from the long fiber fleece 3. In addition, when the formula (2) is not satisfied, if at least one or more turns do not exist in the short fibers 4 at the distance between the adjacent needling marks 5, 5, the short fiber web 1 exists between the needling marks 5, 5. There is a tendency that the extensibility or contractility of the is inhibited. In the present invention, the maximum value of the distance between the needling marks 5, 5 is about 0.3 to 20 mm.

The stretchable non-woven fabric described above is obtained by laminating a short fiber web formed by accumulating helical crimped short fibers on at least one surface of a long fiber web formed by accumulating polyurethane elastic long fibers. It can be obtained by needling. The most preferable manufacturing method is the method described below. That is, on at least one surface of a long fiber web formed by accumulating polyurethane elastic long fibers,
This is a method in which short fiber webs in which short fibers having latent crimping ability are accumulated are laminated, the laminate is subjected to needling, and then heat-treated to cause the short fibers to develop a spiral crimp. The feature of this method is that, as the short fiber constituting the short fiber web, a short fiber which has a linear or loose crimp initially and has a potential crimping ability to develop a crimp in a helical form by heat treatment is used. is there. As the short fibers having latent crimping ability, conventionally known short fibers can be used. For example, a side-by-side conjugate short fiber obtained by laminating a crescent-shaped filament component composed of the polymer component A and a crescent-shaped filament component composed of the polymer component B can be used. In such short fibers, since the heat shrinkage ratios of the polymer components A and B are different from each other, crimps appear spirally when heat is applied. In particular, it is preferable to use, as the polymer components A and B, side-by-side type polyester composite short fibers using polyester polymers having different degrees of polymerization. Such a conjugate fiber can be easily obtained by conjugate spinning of each of the polymers A and B. As a commercially available product, a product number “C-81” manufactured by Kanebo Co., Ltd. or a product number “Tetron T-24” manufactured by Toray Industries, Inc. can be used.

A short fiber web is prepared using short fibers having latent crimping ability as described above, and this is laminated on at least one surface of a long fiber fleece. Then, the needling is performed on the laminate. Thereafter, heat treatment is performed at a temperature at which a helical crimp develops, specifically, at a temperature of about 80 ° C. to 150 ° C., thereby causing the short fiber to develop a helical crimp.
By such a method, a stretchable nonwoven fabric having a configuration as shown in FIG. 1 can be obtained. In the stretchable nonwoven fabric obtained by this method, a helical crimp develops in the short fibers after the short fibers penetrate the polyurethane elastic long fiber gap of the long fiber fleece. In particular, crimps are favorably developed at the ends of the short fibers protruding from the back side of the long fiber fleece, and the crimping of the ends further promotes the tendency that the short fibers are less likely to fall off from the long fiber fleece. It is done.

[0018]

Example 1 First, a basis weight 50 formed by accumulating polyurethane elastic filaments was used.
A long-fiber fleece having a g / m ² and a thickness of 0.5 mm (trade name “Espancione” manufactured by Kanebo Co., Ltd.) was prepared. on the other hand,
Spreading and accumulating a side-by-side type polyester-based conjugate short fiber with a fiber diameter of 3 denier and a fiber length of 51 mm (manufactured by Toray Industries, Inc., product number "Tetron T-24") having latent crimping capacity by carding method A 30 g / m ² short fiber web was made. A short fiber web was laminated on one side of the long fiber fleece, and needling was performed with a # 36 needle from the short fiber web side of the laminate. At this time, the needling density was 50 yarns / cm ² . Next, the short fiber web was further laminated on the long fiber fleece side, and needling was performed from the short fiber web side under the same conditions as described above. Therefore, the maximum value of the distance between the needling marks was about 1 mm. This laminated web is subjected to a heat treatment under the condition of 140 ° C. under no tension,
A helical crimp was developed in the short fibers. The number of turns of the crimp was about 95 over the entire length of the short fiber. The elastic nonwoven fabric obtained as described above has a basis weight of 130 g / m ^2.
The thickness was 2 mm and the apparent density was 0.065 g / cc. The expansion and contraction rate is 85%, the residual strain is 13%,
The breaking elongation was 190%. 50% for this elastic non-woven fabric
The stretch and release of stretch were repeated 20 times, but the original form was maintained as it was, and the stretch was excellent in durability. Therefore, this stretchable nonwoven fabric could be suitably used as a base cloth for a plaster.

Example 2 The short fiber web used in Example 1 was subjected to a temperatureless process under tension.
Heat treatment was performed at 140 ° C. As a result, the short fiber web shrinks by 25% in the warp direction and 30% in the weft direction, and has a basis weight of about 50%.
g / m ² of short fiber web. The short fibers in the short fiber web exhibited spiral crimps, and the number of turns was about 80 over the entire length of the short fibers. This short fiber web was laminated on the long fiber fleece used in Example 1, and subjected to needling in the same manner. After the needling, heat treatment was performed under the same conditions as in Example 1. The stretchable nonwoven fabric obtained as described above had a basis weight of about 150 g / m ² , a thickness of about 2.5 mm, and an apparent density of about 0.05 g / cc. In addition, the stretch ratio is 130%,
The residual strain was 17%. 100% for this elastic non-woven fabric
The elongation and de-elongation were repeated 10 times, but the original form was maintained as it was, showing excellent stretchability.

Example 3 A needling density of 50 fibers / cm ² and, as shown in FIG.
Needling was performed such that the needling marks were ridge-shaped. Except for this, an elastic nonwoven fabric was obtained in the same manner as in Example 2. Therefore, the maximum value of the distance between the needling marks corresponded to the distance between the ridges, and was about 20 mm. The stretch ratio of this stretchable nonwoven fabric was 110% in a direction perpendicular to the ridge and 70% in a direction parallel to the ridge. The residual strain was 22% in the direction perpendicular to the ridge and 11% in the direction parallel to the ridge. Therefore, this stretchable nonwoven fabric was rich in anisotropy, bulky and good in touch.
This stretchable nonwoven fabric was suitable for use as cotton in skiwear trousers.

Embodiment 4 Embodiment 3 is similar to Embodiment 3 except that a needling mark is formed as shown in FIG.
In the same manner as in the above, a stretchable nonwoven fabric was obtained. Therefore, the maximum value of the distance between the needling marks corresponds to the distance between the rectangles, and
It was 15 mm. This stretchable nonwoven fabric had no anisotropy in the stretch ratio and residual strain in the warp and weft directions, had a rectangular uneven portion due to needling marks, and had an elegant appearance. This stretchable nonwoven fabric could be suitably used for supporters such as night caps.

[0022]

As described above, the stretchable nonwoven fabric according to the present invention is formed by laminating a short fiber web formed by accumulating helical crimped short fibers on at least one surface of a long fiber fleece. The short fibers penetrate between the polyurethane elastic long fibers in the long fiber fleece by needling. Accordingly, the action of the long fiber fleece in needling, that is, the expansion and contraction of the long fiber gap due to the elasticity of the polyurethane elastic long fiber of the long fiber fleece, causes the short fibers penetrating the long fiber fleece to become strongly long fibers. It is gripped by fleece. Also, the short fibers are firmly held by the long fiber fleece due to the adhesiveness of the polyurethane elastic long fibers. Further, the short fibers are less likely to fall off from the long fiber fleece due to the spiral crimp present at the ends of the short fibers penetrating the long fiber fleece. By the synergistic action of each of the above actions, the stretchable nonwoven fabric according to the present invention, when repeatedly used, has shorter fibers falling off from the long fiber fleece than the nonwoven fabric described in JP-A-61-146004. This has the effect of being difficult to perform. In addition, since short fibers constituting the short fiber web have a helical crimp, they are entangled intricately between the crimps of the short fibers, preventing the entanglement from being untangled and the surface of the stretchable nonwoven fabric becoming fluffy. This has the effect of being able to do so.

The stretchable nonwoven fabric according to the present invention further comprises a long fiber fleece formed by accumulating polyurethane elastic long fibers;
Because it is formed by laminating a short fiber web having a spiral crimp, both the long fiber fleece and the short fiber web have excellent elasticity, and as a result, the effect of significantly improving the elasticity of the nonwoven fabric is obtained. Play. In particular, the nonwoven fabric obtained by needling under the conditions as described in claim 4 has short fibers whose both ends are fixed to the long-fiber fleece by needling, and a helical crimp exists between the fixing portions. Therefore, the short fibers follow the expansion and contraction of the long fiber fleece while the short fibers are fixed. Therefore, the short fiber web hardly suppresses the elasticity of the long fiber fleece, and this nonwoven fabric has an effect of having good elasticity.

Further, as described in claim 5, if the stretchable nonwoven fabric according to the present invention is obtained using short fibers having latent crimping ability, the end portions of the short fibers penetrating the long fiber fleece can be obtained. The effect is that crimps are favorably expressed and the short fibers are more difficult to fall off from the long fiber fleece.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view of a stretchable nonwoven fabric according to an example of the present invention.

FIG. 2 is a plan view schematically showing a needling mark applied by a method according to an example of the present invention.

FIG. 3 is a plan view schematically showing a needling mark applied by a method according to an example of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Short fiber web 2 Long fiber fleece 3 Polyurethane elastic long fiber 4 Short fiber 5 Needling mark

Continuation of the front page (56) References JP-A-60-146004 (JP, A) JP-A-48-38191 (JP, U) JP-B-46-18825 (JP, B1) (58) Fields investigated (Int) .Cl. ⁶ , DB name) D04H 1/00-18/00 D03D 15/08

Claims (5)

(57) [Claims] A short fiber web in which short fibers having helical crimps are laminated on at least one surface of a long fiber fleece in which polyurethane elastic long fibers are accumulated, and the short fibers are needling. A stretchable nonwoven fabric characterized in that the long nonwoven fabric penetrates between the polyurethane elastic long fibers of the long fiber fleece and the short fibers are entangled with each other. 2. The stretchable nonwoven fabric according to claim 1, wherein the stretchability in at least one direction is 30% or more. 3. The stretchable nonwoven fabric according to claim 1, wherein the residual strain is at least 30% or less. 4. The stretchable nonwoven fabric according to claim 1, wherein the following formulas (1) and (2) are satisfied. Note L (mm)> N (mm) ... (1) [T (times) / L (mm)]> [1 / N (mm)] ... (2) (However, N (mm) is The maximum value of the distance between adjacent needling marks is represented, L (mm) represents the length of short fibers, and T
(Times) represents the number of turns over the entire length (L) of the short fiber. ) 5. A short fiber web in which short fibers having latent crimping ability are accumulated on at least one surface of a long fiber fleece in which polyurethane elastic long fibers are accumulated, and the laminate is subjected to needling. 2. The method for producing a stretchable nonwoven fabric according to claim 1, wherein the short fiber is subjected to a helical crimp after heat treatment.