JPH05163658A - Cushion structure and its use - Google Patents

Abstract

PURPOSE:To obtain the cushion structure excellent in cushioning characteristics, compressive resilience, etc., and without an appearance of uneven processing by interlacing and heat fusing nonelastic polyamide crimped staple fibers and specific elastic conjugate fibers. CONSTITUTION:(A) Nonelastic polyamide crimped staple fibers, (B) elastic conjugate fibers composed of (i) a thermoplastic elastomer having a melting point lower by >=40 deg.C than that of polyamide constructing component A and (ii) nonelastic polyamide, the component (i) covering >=1/2 of the conjugate fiber surface, are blended to form a web having >=30cm<3>/g bulkiness and three- dimensionally interlaced points between the conjugate fibers and between the component A and the conjugate fiber, and subjected to heat treatment at a temperature lower than the melting point of the component A and 10-80 deg.C higher that of the component (i) to obtain the objective structure by heat fusing at least a part of the interlaced points of the fibers.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel cushion structure in which non-elastic polyamide crimped short fibers are used as a matrix, and heat fixing points of elastic composite fibers are dispersed in the matrix, and a method for producing the same.

[0002]

2. Description of the Related Art In the field of cushion structures used for furniture, beds, etc., urethane foam, non-elastic polyester crimped short fiber wadding, polyester cotton crimped short fiber-bonded resin cotton or hard cotton are used. Has been done.

However, the urethane foam is
There are problems that it is difficult to handle chemicals and the like used during the production and that CFCs are discharged. Further, the obtained urethane foam has a unique compression characteristic that it is hard in the initial stage of compression and then suddenly sinks. Therefore, not only the cushioning property is poor, but also the bottoming feeling is large. Moreover, since the foam has poor air permeability, it tends to get damp and is often not preferred as a cushion structure. Further, since urethane foam is soft and foamed, it has a drawback that it has a poor resilience against compression. In order to increase the resilience, it is sufficient to increase the density of the urethane foam, but in this case, there is a fatal defect that the weight is increased and the air permeability is further deteriorated. Next, in the non-elastic polyester short fiber wadding, since the aggregate structure is not fixed, the shape easily collapses during use, the constituent short fibers move, or the short fibers are crimped. Then, there is a drawback that the bulkiness and the repulsion property are greatly reduced.

On the other hand, a non-elastic polyester crimped short fiber aggregate is treated with a resin (for example, an acrylate polymer),
A resin fiber or a solid cotton fixed with a binder fiber (Japanese Patent Laid-Open No. 58-31150) composed of a polymer having a melting point lower than that of the polymer forming the matrix short fiber has a weak fixing force and has a polymer film. Has a low elongation and a low recovery property against stretching, so the durability of the fixing point is low, and if the fixing point is deformed during use, it will be destroyed or recovery from deformation will be poor, resulting in morphological stability. And the repulsion property is greatly reduced. Moreover, since the fixing point is a polymer having a small elongation and is hard and has no mobility, only a cushioning property is obtained. In addition, since the fixed non-elastic polyester has low extension elastic recovery, strain is likely to remain due to deformation. As one means for enhancing the cushioning property, Japanese Patent Application Laid-Open No. 62-102712 proposes a cushion structure in which the intersections of polyester crimped short fibers are fixed with a urethane foam binder. However, here, since the solution type crosslinkable urethane is impregnated, processing unevenness is likely to occur, and therefore the handling of the treatment liquid is complicated, the adhesiveness between the urethane and polyester fibers is low, and the binder is crosslinked. Therefore, the elongation is low, and since the resin part is foamed, the deformation tends to concentrate partially, so there is a problem that the urethane foam at the fiber crossing part is easily broken when it is greatly deformed, and the durability is low. is there.

[0005]

DISCLOSURE OF THE INVENTION According to the present invention, the fixed state at the crossing point of short fibers is remarkably stabilized, whereby the cushioning property, the compression repulsion property, the compression durability and the compression recovery property are improved. , Is intended to provide a new cushion structure. Further, the present invention is
It is an object of the present invention to provide the above-mentioned cushion structure by a simpler method that does not cause processing unevenness.

[0006]

A novel cushion structure according to the present invention has a non-elastic polyamide crimped short fiber aggregate as a matrix and a density of 0.005 to 0.10 g /
In a cushion structure having a cm ³ and a thickness of 5 mm or more, in the short fiber aggregate, a thermoplastic elastomer having a melting point of 40 ° C. or more lower than the melting point of the polyamide polymer forming the short fibers and an inelastic polyamide are used. In the former, at least the elastic composite fiber (conjugate staple fiber) exposed on the fiber surface is dispersed and mixed,
At that time, in the cushion structure, (A) an amoebar-like omnidirectional flexible heat-fixing point formed by heat fusion of the elastic composite fibers in a state where the elastic composite fibers cross each other, and (B) the elastic composite. Fibers and quasi-omnidirectional flexible heat fixing points formed by heat fusion in a state where the non-elastic polyamide short fibers intersect with each other, and between adjacent flexible heat fixing points ((( Between A)-(A), between (A)-(B), and (B)
-(B)) in the elastic composite fiber group, a part of the composite fibers is characterized by having at least one spindle-shaped node along the longitudinal direction.

The method for producing the above-mentioned novel cushion structure according to the present invention has a melting point of 40 ° C. or more lower than the melting points of the non-elastic polyamide crimped short fibers and the polyamide polymer constituting the non-elastic polyamide crimped short fibers. Elastic composite fiber comprising a thermoplastic elastomer and a non-elastic polyamide, the former being mixed with elastic composite fiber occupying at least ½ of the fiber surface to form a web having a bulkiness of at least 30 cm ³ / g. A temperature lower than the melting point of the polyamide polymer and 10 to 80 ° C. higher than the melting point of the elastomer after forming a three-dimensional fiber crossing point between each other and between the non-elastic polyamide crimped short fiber and the elastic composite fiber. It is characterized in that at least a part of these fiber intersections is heat-fused by heat-treating at It is intended.

[0008]

The present invention will be specifically described in more detail. In FIGS. 1 and 2, 1 is a non-elastic polyamide crimped short fiber that serves as a matrix of a cushion structure, 2 is a thermoplastic elastomer having a melting point of 40 ° C. or more lower than the melting point of the polyamide polymer that constitutes the short fiber, and The former is an elastic composite fiber made of elastic polyamide and exposed at least on the surface of the fiber, and shows a state of being dispersed and mixed in the matrix. Through this figure, the characteristic feature is that in the cushion structure, as shown in (A), an amoeber-like structure formed by heat-sealing thermoplastic elastomers with elastic composite fibers 2 crossing each other. The omnidirectional flexible heat-fixing point, and the elastic composite fiber 2 and the non-elastic polyamide short fiber 1 as shown in (B) were formed by heat fusion of the elastomer component in a state where they cross each other. The quasi-omnidirectional flexible heat fixation points are scattered (that is, there are no fixation points between matrix short fibers), and moreover, between adjacent flexible heat fixation points ((A)-(A )while,
In the elastic composite fiber group existing between (A) and (B) and between (B) and (B), at least one spindle-shaped node along the longitudinal direction is included in some of these fibers. The part 3 exists.

As used herein, the term "omnidirectional flexible thermal fixation point" means that when a load is applied to the cushion structure, and therefore, a load is also applied to the cushion structure, this fixation point is the load. It means a flexible heat fixing point that is freely deformable along a direction and is recoverable. The heat-fixing points are classified into two, one is an amoeber-like one that is generated by heat-sealing thermoplastic elastomers in a state where elastic composite fibers are crossed with each other as shown in (A) above. The other is that, as shown in (B), the thermoplastic elastomer component in the elastic composite fiber 2 and the non-elastic polyamide crimped short fiber 1 have a crossing angle of 45 ° to 90 ° as shown in FIG. This is the heat fixation point that occurs when the angle θ intersects.

By the way, the elastic composite fibers 2 dispersed and mixed in the matrix are stochastically formed so as to cross each other or the non-elastic polyamide crimped short fibers 1.
It was found that when heat fusion treatment is performed in this state, spindle-shaped nodes indicated by 3 are intermittently generated along the longitudinal direction of the elastic composite fiber 2. The knot portion 3 is generated when a thermoplastic elastomer, which is a component of the elastic composite fiber 2, moves in the fiber axis direction due to the relationship of melt viscosity and surface tension. When the flexible heat-fixing points are formed, the thermoplastic elastomer in a fluid state moves and aggregates at the fiber intersection points, and amoeber-like or quasi-amemeber-like fixing points are formed. That is, as shown in (A), the heat-fixing points generated by heat-sealing the elastic composite fibers eventually become heat-bonding between the spindle-shaped node portions 3, so that an amoeber-like shape is exhibited, while
In forming the heat fixing point of (B), since the spindle-shaped knot portion 3 fixes the non-elastic crimped short fiber 1 by itself, (A)
In comparison with the amoeber shape of the above, it can be said that the shape is a quasi-ameber shape. FIG. 3 is an electron micrograph (3
It is a front view taken from 50 times).

The phenomenon that the spindle-shaped knuckles 3 are caused by the local movement / aggregation of the thermoplastic elastomer is caused by the flexible heat fixing point (A) in the cushion structure.
This means that the formation probability of (B) increases accordingly.
Of course, the spindle-shaped nodal portion 3 that was not involved in the fusion remains, and as a result, the heat fixing points (A)-(A), (A)-
The parts (B) and (B)-(B) may be connected by an elastic composite fiber in which a spindle-shaped node is partially left.

In forming the flexible heat fixing point as described above, the density of the cushion structure itself is also involved. When the density is higher than 0.10 g / cm ³ , the fiber density becomes excessively high, and the thermoplastic elastomers are likely to be densely fused to each other. Therefore, in such a structure, the elasticity in the thickness direction is remarkably reduced, the air permeability is extremely reduced, and the composition is apt to become damp, so that it cannot be used as a cushion structure any longer.

On the other hand, when the density is less than 0.005 g / cm ³ , such structure has poor resilience,
The number of non-elastic polyamide crimped short fibers forming the matrix is reduced. As a result, when a load is applied to the structure, each fiber is excessively strained or stressed, and the structure itself easily deforms and loses its durability, so that it cannot be used as a cushion structure.

In this respect, in Japanese Patent Laid-Open No. 58-197312 and Japanese Patent Laid-Open No. 52-85575, most of the elastic composite fibers are fused to each other in a parallel state when viewed substantially from the cross-sectional direction. Is recommended. However, such a situation should be absolutely avoided in the present invention.

When the cushion structure of the present invention is compared with the conventional cushion structure, there are the following significant differences between them.

In the conventional product, for example, only the crossing points of the non-elastic crimped short fibers constituting the matrix are fixed with a non-fiber resin or a solution type cross-linkable urethane, whereas the cushion of the present invention is used. In the structure,
No fixed point is formed at the intersection of the crimped short fibers forming the matrix, and the fixed point is the intersection of the elastic composite fibers and the intersection of the elastic composite fiber and the crimped short fiber forming the matrix. Only in the case of the elastic composite fiber is formed by thermal fusion of the thermoplastic elastomer. Furthermore, in a cushion structure using a composite fiber having a low melting point non-elastic polymer as a fusion component as a binder, the heat fixing point is close to a point adhesive shape, and it does not take an amoeber-like shape as in the present invention. Absent. Moreover, the fixing points are inflexible, the binder fibers themselves existing between the fixing points do not have spindle-shaped nodes, and the recovery from deformation is poor. In the present invention, it exhibits omnidirectional flexibility, and these flexible fixing points are connected by elastic composite fibers having a high degree of deformation recovery.

From the above, in the cushion structure of the present invention, the heat fixing points (A) and (B) exhibiting omnidirectional flexibility, and further, the elastic composite fiber connecting these heat fixing points. Since it has a three-dimensional elastic structure, a cushion structure excellent in compression rebound and compression recovery can be realized.

The features of the omnidirectional flexible heat fixing point (A) of the present invention will be touched upon. Since the points are generated by the movement / aggregation of the thermoplastic elastomer in the composite fiber, they cover the intersection points of the fibers in a wide range and the surface thereof is smooth. In addition, a curved surface like a hyperbola is present at the outer circumference of the intersection of the fibers. Therefore, (i) there is no stress concentration. (Ii) Since the strength and the elongation are remarkably improved, they are not broken even by repeated compression. (Iii) Hard to be deformed by compression (strong repulsion against deformation). (Iv) Once deformed, it is easy to deform in any direction (omnidirectionally). (V) Further, it is easy to recover smoothly from deformation from any direction. (Vi) Since the adjacent heat-fixing points are connected to each other by the elastic composite fiber, it is easy to return to the original position even if the heat-fixing points are displaced.

On the other hand, the quasi-omnidirectional flexible heat fixing point (B)
However, it is easily understood that the degree thereof is inferior to that of the heat fixation point of (A) but shows the same tendency.

Next, the requirements associated with the cushion structure of the present invention will be described.

First, the amoebar-like omnidirectional flexible heat fixing point preferably has a W / D in the range of 2.0 to 4.0. Here, W is the width of the heat fixing point, and is the average value of W ₁ and W ₂ as shown in FIG. D is the average diameter of the elastic composite fibers involved in heat fixation, and each diameter is the diameter of the part adjacent to the root of the fixation point (d ₁ ,
d ₂ , d ₃ and d ₄ ). In addition, the elastic composite fibers located between these heat fixing points should have at least 10 ^-2 cm.
In many cases, spindle-shaped knots 3 are present at intervals of. Further, the elastic composite fibers located between these heat-fixing points may exist in the form 4 which is curved in a loop shape, or sometimes in the form which develops a coil-like elastic crimp, as shown in FIG.

In the present invention, the omnidirectional or quasi-omnidirectional flexible heat fixing point (hereinafter, both may be collectively referred to simply as "heat fixing point") is a load (compressive force) on the cushion structure. ) Is applied, it freely deforms in response to the stress and strain, and by dispersing these stress and strain, it has the function of reducing the stress and strain applied to the crimped short fibers constituting the matrix. Therefore, the physical properties of the heat fixing point cannot be overlooked. As for these physical properties,
The breaking strength, the breaking elongation, and the 10% elongation elastic recovery rate defined later are included. Breaking strength is 0.3g / de
It is preferably in the range of to 5.0 g / de. When the breaking strength is less than 0.3 g / de, when the cushion structure is subjected to a large deformation of compression (for example, 75% of the initial thickness), the heat fixing point is easily broken, resulting in durability and shape stability. May decrease.

On the other hand, when the strength of the heat-fixing point exceeds 5 g / de, the fusion process is performed at a considerably high temperature, and as a result, the physical properties of the crimped short fibers themselves constituting the matrix deteriorate.

The breaking elongation is preferably in the range of 15 to 200%. If the elongation at break is less than 15%,
When a large deformation due to compression is applied to the cushion structure,
In addition to further displacement and displacement occurring at these heat fixing points, the crossing angle θ also changes beyond the deformation limit, and eventually the fixing points are easily broken.

On the other hand, if the elongation exceeds 100%, the thermal fixation point is likely to be displaced when the same displacement is applied, and the durability may be deteriorated.

Further, the 10% elongation elastic recovery rate is preferably 80% or more, and particularly preferably in the range of 80 to 95%. When the 10% elongation elastic modulus is less than 80%, when stress or displacement occurs at the heat fixing point, the recovery property against deformation is lowered, and durability against repeated compression and dimensional stability may be deteriorated.

In the present invention, the non-elastic polyamide crimped short fibers constituting the matrix are ordinary nylon 6,
Nylon 66 and other nylon 2, nylon 3, nylon 4, nylon 7, nylon 11, nylon 12, nylon 610, nylon 4, 6 and other aliphatic polyamides or copolymers of these short fibers or their fibers It is a blended cotton or a composite fiber composed of two or more of the above-mentioned polymer components, and is particularly nylon 6 and nylon 66 in view of heat resistance and cushioning material repulsion.
Is preferred. The cross-sectional shape of the single fiber may be circular, flat, atypical or hollow. Further, the thickness of the single fiber is preferably in the range of 2 to 500 denier, particularly 6 to 300 denier. When the thickness of the single fiber is small, the density of the cushion structure is increased and the elasticity of the structure itself is often lowered. If the monofilament is too thick, the handleability, particularly the web forming property, deteriorates. Further, the number of constituents is too small, the number of intersections formed with the elastic composite fiber is small, and the elasticity of the cushion structure is less likely to be exhibited, and at the same time, the durability may be reduced. Further, the texture becomes too hard.

On the other hand, the elastic composite fiber used for forming the heat fixing point which plays an important role in the present invention is formed by a thermoplastic elastomer and a non-elastic polyamide. In that case, it is preferable that the former occupy at least ½ of the fiber surface. In terms of weight ratio, it is suitable that the former and the latter are in a composite ratio of 30/70 to 70/30.
As the form of elastic composite fiber, side-by-side,
Either the sheath-core type may be used, but the latter is preferable. In this sheath-core type, the inelastic polyamide is of course the core, but the core may be concentric or eccentric. In particular, the eccentric type is more preferable because the coil-shaped elastic crimp is developed.

The thermoplastic elastomer is preferably a polyurethane elastomer or a polyester elastomer.

As the polyurethane elastomer, a low melting point polyol having a molecular weight of about 500 to 6000, such as dihydroxypolyether, dihydroxypolyester, dihydroxypolycarbonate, dihydroxypolyesteramide, and an organic diisocyanate having a molecular weight of 500 or less, such as p, p '- Diphenylmethane diisocyanate, tolylene diisocyanate, isophorone diisocyanate, hydrogenated diphenylmethane diisocyanate, xylylene diisocyanate, 2,6-diisocyanate methylcaproate, hexamethylene diisocyanate and the like, and a chain extender having a molecular weight of 500 or less, such as glycol, amino alcohol or triol. It is a polymer obtained by the reaction with. Among these polymers, particularly preferred are polyurethanes using polytetramethylene glycol, or poly-ε-caprolactone or polybutylene adipate as a polyol. In this case, as the organic diisocyanate, p,
P'-diphenylmethane diisocyanate is preferred. As the chain extender, p, p'-bishydroxyethoxybenzene and 1,4-butanediol are suitable.

On the other hand, as the polyester elastomer, a polyether ester block copolymer obtained by copolymerizing thermoplastic polyester as a hard segment and poly (alkylene oxide) glycol as a soft segment, more specifically, terephthalic acid, Isophthalic acid, phthalic acid, naphthalene-2,6-dicarboxylic acid, naphthalene-2,7-dicarboxylic acid, diphenyl-4
4'-dicarboxylic acid, diphenoxyethanedicarboxylic acid, aromatic dicarboxylic acid such as sodium 3-sulfoisophthalate, alicyclic dicarboxylic acid such as 1,4-cyclohexanedicarboxylic acid, succinic acid, oxalic acid, adipic acid,
At least one dicarboxylic acid selected from aliphatic dicarboxylic acids such as sebacic acid, dodecanedioic acid and dimer acid or their ester-forming derivatives, and 1,4-butanediol, ethylene glycol, trimethylene glycol, tetramethylene Aliphatic diol such as glycol, pentamethylene glycol, hexamethylene glycol, neopentyl glycol, decamethylene glycol, or 1,1-cyclohexanedimethanol,
At least one diol component selected from alicyclic diols such as 1,4-cyclohexanedimethanol and tricyclodecanedimethanol, or ester-forming derivatives thereof, and an average molecular weight of about 400 to 5,000.
Polyethylene glycol, poly (1,2- and 1,3-propylene oxide) glycol, poly (tetramethylene oxide) glycol, a copolymer of ethylene oxide and propylene oxide, a copolymer of ethylene oxide and tetrahydrofuran, etc. It is a terpolymer that is composed of at least one of poly (alkylene oxide) glycols.

However, in terms of adhesiveness with non-elastic polyamide crimped short fibers, temperature characteristics, and strength, a block copolymerized polyether polyester having polybutylene terephthalate as a hard segment and polyoxybutylene glycol as a soft segment is used. Is preferred.
In this case, the polyester portion constituting the hard segment is polybutylene terephthalate whose main acid component is terephthalic acid and whose main diol component is butylene glycol component. Of course, a part (usually 30 mol% or less) of this acid component may be substituted with another dicarboxylic acid component or an oxycarboxylic acid component, and similarly, a part (usually 30 mol% or less) of the glycol component is butylene. It may be substituted with a dioxy component other than the glycol component.

The polyether portion constituting the soft segment may be a polyether substituted with a dioxy component other than butylene glycol. In the polymer, various stabilizers, ultraviolet absorbers, thickening and branching agents,
A matting agent, a colorant, and other various improving agents may be added as necessary.

The degree of polymerization of this polyester elastomer is preferably in the range of 0.8 to 1.7, particularly 0.9 to 1.5 in terms of intrinsic viscosity. If this intrinsic viscosity is too low, the heat-fixing points formed with the non-elastic polyamide crimped short fibers constituting the matrix will be easily broken. On the other hand, if the viscosity is too high, spindle-shaped knots are less likely to be formed during heat fusion.

As a basic characteristic of the thermoplastic elastomer, a breaking elongation defined later is preferably 500% or more,
More preferably, it is 800% or more. If this elongation is too low, when the cushion structure is compressed and its deformation reaches the heat fixing point, the bond at this portion is easily broken.

On the other hand, the elongation stress of 300% of the thermoplastic elastomer is preferably 0.8 kg / mm ² or less, more preferably 0.6 kg / mm ² or less. If this stress is too large, it becomes difficult for the heat fixing point to disperse the force applied to the cushion structure, and when the cushion structure is compressed, the heat fixing point may destroy the heat fixing point, or Even if it is not destroyed, the non-elastic polyamide crimped short fibers constituting the matrix may be distorted or crimped.

The 300% elongation recovery rate of the thermoplastic elastomer is preferably 60% or more, more preferably 7%.
It is 0% or more. If the extension recovery rate is low, the cushion structure may be compressed and the heat fixing point may be deformed, but it may be difficult to return to the original state.

These thermoplastic elastomers have a melting point lower than that of the polymer constituting the non-elastic polyamide crimped short fibers, and heat the crimped crimped fibers during the fusion treatment for forming the heat fixing point. It needs to be something that does not let you down. From this point of view, the melting point is preferably 40 ° C. or more, particularly 60 ° C. or more lower than the melting point of the polymer constituting the short fiber. The melting point of such a thermoplastic elastomer can be a temperature in the range of, for example, 130 to 220 ° C.

If the difference in melting point is less than 40 ° C., the heat treatment temperature in the fusion processing described below becomes too high, causing crimping of the non-elastic polyamide crimped short fibers, and the crimped short. It reduces the mechanical properties of the fiber. When the melting point of the thermoplastic elastomer is not clearly observed, the melting point is replaced with the softening point.
On the other hand, as the non-elastic polyamide used as the counterpart component of the above-mentioned thermoplastic elastomer, the polyamide polymer constituting the crimped short fibers forming the matrix as described above is adopted. Among them, nylon 6 and Nylon 66 is more preferably adopted.

The above-mentioned composite fiber is 10 to 70%, preferably 20 to 60% based on the weight of the cushion structure.
It is dispersed and mixed in the range of%. If the dispersion / mixing rate is too low, the number of heat fixing points may be reduced, the cushion structure may be easily deformed, and the elasticity, repulsion and durability may be low.

On the other hand, if the dispersion / mixing rate is too high, the number of constituent non-elastic polyamide crimped short fibers that impart repulsion becomes too small, and the repulsion as a structure becomes insufficient.

Further, since the cushion structure is a material which is compressed in the thickness direction and repels, it has a thickness of at least 5 mm, preferably 10 mm or more, more preferably 20 mm or more in order to exert its performance. Preferably. As described above, the thickness is usually about 5 to 30 mm, but in some cases, it may reach about 1 to 2 m.

In the production of the cushion structure of the present invention, the non-elastic polyamide crimped short fibers and the thermoplastic elastomer having a melting point lower than the melting point of the polyamide polymer constituting the non-elastic polyamide crimped short fibers by 40.degree. By forming a web having a bulkiness of at least 30 cm ³ / g, which is made of elastic polyamide, the former is mixed with elastic composite fibers which occupy at least ½ of the fiber surface to form a web between the composite fibers and After forming a three-dimensional fiber crossing point between the elastic polyamide crimped short fiber and the composite fiber, 10 to 80 ° C. from the melting point of the elastomer.
It heat-processes at high temperature and heat-bonds at least one part of a fiber entanglement point.

More specifically, a crimp is applied, and 40 cm ³
/ G, preferably 60 cm ³ / g a non-elastic polyamide short fiber lump (or web) having a bulkiness, and preferably an elastic composite fiber lump expressing crimps, both of which are uniformly mixed through a card. To get Due to such blended cotton, innumerable fiber cross points are formed in the web between the elastic composite fibers and between the composite fibers and the non-elastic polyamide crimped short fibers. Next, such a web is placed in a mold so as to have a predetermined density and is lower than the melting point of the polyamide polymer and 10 to 80 ° C. higher than the melting point (or flow starting point) of the thermoplastic elastomer in the elastic composite fiber. By performing the fusion treatment at a temperature, the elastomer component is fused at the fiber crossing points, and the amoeber-like omnidirectional flexible heat-fixing point of (A) and the quasi-omnidirectional flexibility of (B) described above. It forms a heat fixing point.

Here, the three-dimensional fiber crossing points are literally crossing points existing at an angle of less than 90 ° with respect to a plane parallel to the thickness direction of the web. Of course, in this web, a large number of fiber crossing points are simultaneously formed on a plane parallel to the horizontal plane of the web. However, they are rather characteristic of aggregates (eg nonwovens) such as artificial leather, which have a much higher density than the cushion structure.
In this respect, the method of the present invention is characterized in that a three-dimensional fiber crossing point is formed by setting the web density to 30 cm ³ / g or more in addition to the above planar fiber crossing point. Most of the three-dimensional fiber crossing points are maintained even when a cushion structure of 0.1 g / cm ³ or less is formed after the heat fusion treatment.

The non-elastic polyamide crimped short fibers and elastic composite fibers can be obtained by a known spinning method. At that time, the polymer to be used, the thickness of the single fiber, the mixing ratio of the both, and the like are as described above. However, both fibers are preferably stretched 1.5 times or more after spinning. A cushion structure made of stretched fibers is superior in resilience to a cushion structure made of unstretched fibers and is less tired. The reason for this is that the amorphous part is relaxed in the process of being stretched into short fibers and in a relaxed state, and the amorphous parts become randomized, resulting in a fiber structure with more elasticity, which is maintained even after melting and solidification. It is presumed that it is easy. Further, the elastic composite fiber preferably has a low heat shrinkage. If the heat shrinkage is high, the thermoplastic elastomer is significantly shrunk by the time of heat fusion until it is melted, and the number of fibers which are converted into heat fixation points among the fiber crossing points is reduced. In order to reduce the heat shrinkage of the elastic composite fiber, 40 to 1 after stretching is used.
The heat treatment may be performed at a temperature of 20 ° C. for 20 seconds or more.

As the crimp applied to the short fibers, the indentation crimp is sufficient. In that case, the number of crimps is 5 to 15 / inch
(Measured according to JIS L1045) is preferable, and 8 to 1
2 pieces / inch (same) is more preferable. However, it is also useful to impart anisotropy to the fiber structure by imparting anisotropy to the fiber structure by means such as anisotropic cooling at the time of spinning each fiber, and then subjecting it to indentation crimping. Alternatively, it may be obtained by subjecting the long fibers to false twisting, heat setting, untwisting, and cutting.

[0048]

[Effect] The cushion structure of the present invention has less initial hardness in compression than urethane foam and has a large resilience, and since the cushion structure increases substantially in proportion to the amount of compression, it has extremely little feeling of bottoming. Moreover, since the structure itself has a low density, it is highly breathable and there is no risk of stuffiness.

Regarding the durability against repeated compression, the heat-fixing point is not easily broken, and even if it is deformed, it is easy to return to its original shape after unloading, and its compression durability is excellent.

On the other hand, in the production of this structure, a uniform cushion structure can be obtained by a simple and short process of dry heat treating the web of short fibers, and the hardness of the structure may be partially changed. The hardness in the thickness direction can be easily changed by changing the mixing ratio of fibers, the structure of fibers, or the density.

Therefore, the cushion structure of the present invention is excellent in cushioning property, repulsion property, durability and recovery property, and has high breathability, so that it does not easily get damp. Further, in manufacturing, unevenness in processing is unlikely to occur, diversification in processing can be easily achieved, and manufacturing can be performed in a short process.
Therefore, the range of use of this structure is suitable for various cushion materials, such as cushion materials for furniture, beds, bedding, and various seats.

The present invention will be further described with reference to examples. The following measurements were carried out in the examples.

Measurement of Breaking Strength and Breaking Elongation at Thermal Fixing Point In a cushion structure, two fibers are 45 ° to 90 °.
Sampling is performed by intersecting at a crossing angle of °, and a portion where the crossing points are fixed includes two different fibers.
Next, the two different fibers fixed and connected to each other with the heat fixing point at the center are attached to the grip portion of the tensile tester at intervals of 2 mm in sample length, and pulled at a speed of 2 mm / min.
The elongation when the initial load of 0.3 g is read as looseness, and the sample is further pulled to measure the maximum load (g) until the fixing point of the sample breaks and the elongation at that time. The breaking strength and the breaking elongation of each were calculated. The number of tests for calculating the breaking strength is represented by an average value of the number of samples n = 20 with 10 randomly sampled fixation points (A) and 10 fixation points (B).
(Number of (A) :( B) is 1: 1)

Breaking strength (g / de) = [load (g) at cutting] / (average denier of two short fibers in the sample) Breaking elongation (%) = [(E ₂ -E ₁ ) / (L + E ₁ )] ×
100 E ₁ ; Looseness (mm) E ₂ ; Elongation at maximum stress (mm) L; Grip spacing (mm)

Measurement of 10% elongation elastic recovery rate of heat fixing point Sampling and sample mounting were carried out in the same manner as in the case of measuring the breaking strength and breaking elongation of the heat fixing point, and the initial load was 0.3.
Set the test length of L _{0 to} the point multiplied by g and start the tension at 2 mm / min. After pulling to 10% elongation to the test length,
Immediately remove the weight at the same speed, leave the weight for 2 minutes, and then pull again at the same speed. The 10% elongation elastic recovery rate was calculated from the difference l (mm) between the initial test length of 0.3 g and the test length when the tensile load of 0.3 g was applied again by the following formula. The number of tests and sampling are the same as in the case of measuring the breaking strength.

10% elongation elastic recovery = (1-l / l ₀ ) × 100 l ₀ ; 10% elongation length (mm) = L ₀ × 0.1 l; residual elongation (mm) (first 0.3 g Trial length when initial load is applied-Trial length when second 0.3 g load is applied)

Measurement of Cushion Material Thickness and Density The basis weight (g /
m ² ), and the thickness under a load of 0.5 g / cm ² (c
m) was measured and the density (g / cm ³ ) was calculated.

Measurement of Intrinsic Viscosity of Polyester Elastic Body The intrinsic viscosity of the polyester elastic body was measured at 35 ° C. by using an equal weight mixed solvent of phenol and tetrachloroethane.

Measurement of the bulkiness of the web The short fibers are webbed and overlapped to give a basis weight of 1000 g /
A load of 10 g / cm ² was applied to the sample cut out as m ² for 1 minute, and 1 minute after the release, the thickness was measured under a load of 0.5 g / cm ² to calculate the bulkiness (cm ³ / g).

Measurement of Physical Properties of Thermoplastic Polymer (1) Preparation of Film for Measurement Melting the polymer in a nitrogen atmosphere at 300 ° C. and defoaming 1
Rolled at a speed of 20 m / min between a pair of metal rollers having a clearance of 0.5 mm at 00 ° C. and rolled to a thickness of about 0.
A 5 mm film was obtained. 5mm vertically from the film
A sample having a width of 50 mm and a length of 50 mm was punched out to obtain a film for measuring physical properties of a thermoplastic polymer.

(2) Measurement of elongation at break The elongation at break was measured with a film for measuring physical properties having a test length of 50 mm and a tensile speed of 50 mm / min.

(3) Measurement of 300% elongation stress The film for physical properties measurement has a trial length of 50 mm and a tensile speed of 50 mm / min, and is 300% stretched. The calculated value was 300%, and the elongation stress (kg / mm ² ) was calculated.

(4) Measurement of 300% elongation recovery rate The sample length of the film for measuring physical properties was set to 50 mm, the pulling speed was set to 50 mm / min, and the film was pulled to 300% and then returned to the original zero point at a speed of 50 mm / min and left for 2 minutes. After that, it was pulled again at a pulling speed of 50 mm / min. Determine the loosening length (mm) of the sample from the rise of the initial stress and the rise after leaving (2g stress), and the ratio (%) to the extension amount 150mm is calculated by (1-loosening length / 150) × 100 (%) It was calculated to be 300% elongation recovery rate.

(5) Melting point A melting peak temperature was determined by using a thermal differential analyzer 990 type, manufactured by Du Pont, at a temperature rising rate of 20 ° C./min.

(6) Softening point Using a trace melting point measuring device (manufactured by Yanagimoto Seisakusho Co., Ltd.), about 3 g of polymer was sandwiched between two cover glasses, and the temperature was raised at about 10 ° C./min while gently holding down with tweezers. The temperature is raised and the thermal change of the polymer is observed. At that time, the temperature at which the polymer softens and begins to flow is defined as the softening point.

The cushioning material has good compression resilience and compression durability.
Measuring density adjusted to flat plate shape 0.035g / cm ³ , thickness 5cm
The cushion structure (1) was compressed by 1 cm with a cylindrical rod having a flat lower surface with a cross-sectional area of 20 cm ² , and the stress (initial stress) was measured, and this was designated as compression rebound. 800g / cm after measurement
The operation of compressing under a load of ² for 10 seconds, removing the weight, and leaving for 5 seconds was repeated 360 times, and after 24 hours, the compressive stress was measured again. The ratio% of the stress after repeated compression to the initial stress was defined as the compression durability of the cushion material.

Measurement of compression recovery of cushion structure Density adjusted to flat plate shape 0.035 g / cm ³ , thickness 5 cm
10 the cushion structure to a load of 500 g / cm ² a cylindrical rod having a flat lower surface of the cross-sectional area 20 cm ²
After compression at a speed of 0 mm / min, the load was immediately removed at a speed of 100 mm / min, and the compression recovery (Rc) was calculated from the area obtained from the compression length-stress curve (FIG. 4) drawn by this measurement. ..

Compression recovery (RC)% = [(area surrounded by ODAB) / (area surrounded by OCAB)] × 100

[0069]

Example 1 80/2 terephthalic acid and isophthalic acid
Polybutylene-based terephthalate 38 obtained by polymerizing an acid component mixed with 0 (mol%) and butylene glycol
% (Wt%) to polybutylene glycol (molecular weight 2
000) 62% (% by weight) was reacted by heating to obtain a block copolymerized polyether polyester elastomer. The thermoplastic elastomer has an intrinsic viscosity of 1.0 and a melting point of 15
Breaking elongation at 5 ° C, film is 1500%, 300% elongation stress is 0.3kg / mm ² , 300% elongation recovery rate is 75%
Met.

This thermoplastic elastomer is used as a sheath, nylon 6 is used as a core, and the weight ratio of core / sheath is 50/50.
Was spun by a conventional method. The conjugate fiber is an eccentric sheath / core type conjugate fiber. This fiber was drawn 2.0 times, cut into 64 mm, and then heat-treated with warm water at 95 ° C. to reduce shrinkage and develop crimp, and dried, and then an oil agent was applied. The thickness of the single fiber of the elastic composite fiber obtained here was 6 denier.

40% (by weight) of this elastic composite fiber and hollow section nylon 6 short fiber having a diameter of 14 denier, a fiber length of 64 mm, and a crimping number of 9 / inch obtained by a conventional method ( Web mass 80 cm ³ / g, Nylon 6 melting point 215
℃) 60% (weight) is mixed with a card, and the bulkiness is 5
A web of 0 cm ³ / g was obtained. The webs were overlaid, placed in a flat-plate mold so as to have a thickness of 5 cm and a density of 0.035 g / cm ^3, and heat-treated at 180 ° C. for 10 minutes to obtain a flat-plate cushion material (thermoplastic elastomer: Occupy (20% by weight) in the cushion structure.

When the cushion structure was observed in detail with an electron microscope, it had the structure shown in FIGS. 5, 6 and 7, and the intersection points of the elastic composite fibers were fused and integrated by the thermoplastic elastomer to form an amoeber. The heat-fixing points are formed in a scattered state (Figs. 1 to 3), and the intersection points of the non-elastic polyamide crimped short fibers and the elastic composite fibers are fused and integrated by the thermoplastic elastomer in the same manner. It was observed that the heat-fixing parts (FIGS. 1 to 3) were formed in a scattered state. W / D of heat fixing point of (A) (n = 1
0) was 2.80. Further, the breaking strength at the heat fixing point including (A) and (B) was 1.2 g / de, the breaking elongation was 55%, and the 10% elongation elastic modulus was 91%. And
The density of the cushion structure is as low as 0.035 g / cm ³ ,
A considerable number of three-dimensionally tightly fused elastic composite fibers were observed. Furthermore, many knots 3 as shown in FIGS. 1 to 3 were also found.

Therefore, the cushion structure was very excellent in air permeability. Further, this cushion structure did not have an initial hardness against compression as seen in urethane foam, and had excellent cushioning properties. Further, the compression resilience and the compression durability were as high as 2 kg and 52%, respectively, and the compression recovery was improved to 66%, which was an extremely ideal cushion structure.

[0074]

[Reference example] 60/40 terephthalic acid and isophthalic acid
A copolymerized polyester was obtained from the acid component mixed in (mol%) and the diol component mixed in ethylene glycol and diethylene glycol at 85/15 (mol%). The intrinsic viscosity of this polymer was 0.8. The melting point is not clear, but since it softened and began to flow from around 100 ° C,
The softening point was set at 110 ° C. Although the strength of this film was about the same as in Example 1, the elongation at break was 5% and it was a hard polymer.

A cushion structure was obtained in the same manner as in Example 1 except that this polymer was used as the sheath component of the composite fiber and the heat treatment temperature was 150 ° C. When the bonding morphology of the obtained cushion structure was observed with an electron microscope, it was not found that it had an amoeber-like heat-fixing point in the present invention, and a spindle-shaped knot was not recognized. Incidentally, W / D of the heat fixation point of (A) was 1.65. Further, the breaking strength at the heat fixing point including (A) and (B) was 0.35 g / de, and the breaking elongation was 4%. Therefore, the 10% elongation elastic modulus at the heat fixing point could not be measured.

The cushioning property of this cushion structure was poor, and the compression resilience at the first time was as high as 5.5 kg, but the compression resilience was significantly reduced at the second and subsequent compressions. Actually, when the compression durability and the compression recovery property were examined, they were 14% and 32%, respectively, and it was a cushion structure having extremely poor durability.

[0077]

[Comparative Examples 1 and 2] The structure obtained in the same manner as in Example 1 except that a web was placed in a mold so that the density was 0.12 g / cm ³ and heat treatment was performed, the density of loose paper was changed. Since the density is too high, the elastic composite fibers cannot form a three-dimensional bonding state inside the structure, and they are fused in a substantially parallel state so that they are dense and the surface is also made dense. It was very heavy because it started. In addition, it was extremely hard against compression and exhibited the appearance of a solidified resin, and could not be used at all as a cushion structure.

The web density is 0.004 g / cm ³
When the web was placed in a mold so as to be heat treated and heat treated, the repulsion property was extremely low and a uniform structure was not obtained, and the obtained structure had a compression repulsion force of 0.1 kg which was extremely low. ..

[0079]

[Comparative Examples 3 to 4] When the heat treatment temperature in Example 1 was set to 158 ° C, the obtained cushion structure was such that the thermoplastic elastomer did not collect at the intersections of the non-elastic polyamide crimped short fibers and barely melted by heat. He was just wearing it, not in an amoeber-like form. And, the strength of this heat fixing point is 0.1 g / de, and this heat fixing point is easily removed,
The compression durability of the cushion structure was also low at 27%. When the heat treatment temperature is 210 ° C., the thermoplastic elastomer is yellowed and has no elasticity, the structure has no repulsion against compression, and the compression durability and the compression recovery are 33%, respectively.
% And 50%.

[0080]

Example 2 Dehydrated polymethylene glycol having a hydroxylation value of 102 and 1,4-bis (hydroxyethoxy)
After mixing and dissolving benzene and agitating with a jacketed ruder, p, p'-diphenylmethane diisocyanate was added and reacted at 85 ° C to obtain a powdery thermoplastic polyurethane elastomer (softening point: 151 ° C), which was extruded from an extruder. Pelletized by. Using this thermoplastic polyurethane elastomer as a sheath and nylon 6 as a core, elastic composite fibers (weight ratio 50/50) were obtained, and a cushion structure was obtained in substantially the same manner as in Example 1.

Morphologically, the obtained cushion structure has a structure in which the composite fibers are fused together at the intersections of the non-elastic polyamide crimped short fibers and the composite fibers with a polyurethane elastomer, and the density is 0. It was 0.035 g / cm ³ , and the air permeability was also high. The W / D of the heat fixing point of (A) was 2.6. Further, the rupture strength at the heat fixing point including (A) and (B) was 0.5 g / de, the rupture elongation was 12%, and the 10% elongation elastic recovery rate was as high as 96%.

This cushion structure was soft and easy to be compressed, and its compression resilience was 1.3 kg, which was slightly low. On the other hand, compression durability and compression recovery are
It was high as 45% and 60%, respectively, and was useful as a cushion structure.

[0083]

[Comparative Example 5] A hollow section nylon 6 short fiber having a denier of 14 denier and a fiber length of 64 mm used in Example 1 was webbed with a card. On the other hand, as a binder solution, urethane prepolymer (Mitsui Nisso Urethane MN3050
And N-80% synthesized by T-80 = 5%), 0.2% of a silicon foam stabilizer was added, the web was immersed in a 40 wt% concentration trichlene solution, and then put into a centrifugal dehydrator,
After drying, the liquid was drained so that the urethane adhesion rate was 30%.

Then, while the impregnated web was packed in a perforated flat plate mold, water vapor of 100 ° C. was blown to cure the urethane binder, and after drying at 120 ° C., the fibrous structure was taken out.

The density of this structure was 0.035 g / cm ³ . However, when the structure was observed with an electron microscope, it was found that the intersection points of the non-elastic crimped short fibers were fixed by the urethane resin, but there was a large variation in the resin adhesion amount between the fixed parts, and the urethane resin part Is in a foaming state,
A hole was found. The strength of this fixing point was as low as 0.1 g / de, and the elongation was 12%. The 10% extension elastic modulus at the fixing point was 65%.

The compression durability of this cushion structure is 40.
%, And the compression recovery rate was 55%, which was rather low, and the cushion structure had a problem in durability.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a cushion structure of the present invention, taken from an electron micrograph (50 ×) of FIG.

FIG. 2 is a cross-sectional view of the cushion structure of the present invention, taken from the electron micrograph (75 ×) of FIG.

FIG. 3 is a front view of amoeber-like omnidirectional flexible heat fixing points and quasi-omnidirectional flexible heat fixing points scattered as peculiar fixing points in the cushion structure of the present invention. 7
The one taken from the electron micrograph (350 times).

FIG. 4 is a graph used to calculate compression recovery of a cushion structure.

FIG. 5 is an electron micrograph (× 59) showing the structure of the cushion structure of the present invention.

FIG. 6 is an electron micrograph (× 75) showing the structure of the cushion structure of the present invention.

FIG. 7 is an electron micrograph (350 times) of amoebar-like omnidirectional flexible heat-fixing points and quasi-omnidirectional flexible heat-fixing points scattered in the cushion structure of the present invention.

[Explanation of symbols]

1 non-elastic polyamide crimped short fiber 2 elastic composite fiber 3 spindle-shaped nodal part 4 loop A amoebic omnidirectional flexible heat-bonding point B quasi-omnidirectional flexible heat-bonding point θ crossing of elastic composite fibers Angle W ₁ , W ₂ Width of heat fixing point d ₁ , d ₂ , d ₃ , d ₄ Diameter of elastic composite fiber

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Makoto Yoshida 3-4-1 Mihara, Ibaraki City, Osaka Prefecture Teijin Limited Osaka Research Center

Claims (3)

[Claims] 1. A non-elastic polyamide crimped short fiber aggregate is used as a matrix and has a density of 0.005 to 0.10 g / cm 3.
³ , in the cushion structure with a thickness of 5 mm or more,
The short fiber aggregate comprises a thermoplastic elastomer having a melting point of 40 ° C. or more lower than the melting point of the polyamide polymer constituting the short fiber and an inelastic polyamide, and the former is an elastic composite fiber exposed at least on the fiber surface. When dispersed / mixed, in the cushion structure, (A) amoebar-shaped omnidirectional flexible heat-fixing points formed by heat-sealing each other in a state where the elastic composite fibers cross each other; and (B) Flexible heat-bonding in which quasi-omnidirectional flexible heat-bonding points formed by heat-sealing in a state where the elastic composite fibers and the non-elastic polyamide-based short fibers are interspersed and adjacent to each other In the composite fiber group existing between the points (between (A)-(A), (A)-(B) and (B)-(B)), some of the composite fibers have a longitudinal direction. There is at least one fusiform node along the Cushion structure which is characterized in that. 2. The cushion structure according to claim 1, wherein the fusion state of the amoebar-like omnidirectional flexible heat fixing points satisfies 2.0 <W / D <4.0. Here, W is the width of the heat fixing point, and D is the average diameter of the fibers involved in the heat fixing point. 3. A non-elastic polyamide crimped short fiber, a thermoplastic elastomer having a melting point of 40 ° C. or more lower than the melting point of a polyamide polymer constituting the non-elastic polyamide crimped short fiber, and a non-elastic polyamide. Elastic composite fibers occupying at least ½ of the surface are mixed together to form a web having a bulkiness of at least 30 cm ³ / g, thereby forming a web between the composite fibers and between the non-elastic polyamide crimped short fibers and the composite fibers. 10 to 8 below the melting point of the polyamide polymer and above the melting point of the elastomer after forming a three-dimensional fiber intersection between
A method for producing a cushion structure, comprising heat-treating at a temperature higher by 0 ° C. to heat-bond at least a part of the fiber entanglement points.