JP2000355865A - Non-woven structure using fibrous wad composed of randomly distributed staple fiber and production of the same structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cushion material scarcely causing deformation due to swelling and/or compression after been loaded in a high temperature atmosphere. SOLUTION: This non-woven structure constituted by adhering many fibrous wads composed of staple fibers features that the fibrous wads comprise matrix fibers and binder fibers and substantially are adhered to one another in part of mutual contact zones, and that the staple fibers making up the fibrous wads are distributed so as to be directed randomly within at least two planes of the wads themselves.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is suitable for use as a cushion material made of a nonwoven fabric, particularly a cushion material for an automobile seat and a hospital mattress.

[0002]

2. Description of the Related Art Conventionally, nonwoven fabric structures made of synthetic fibers have been widely used as cushion materials for bed mats used in houses and hospitals, including seat cushion materials for automobiles. As disclosed in Japanese Patent Application Laid-Open No. 6-294061, a sheet-like material produced by using a short fiber such as polyester as a raw material and molding the short fiber into a fiber assembly by a filling method in which the short fiber is blown into a mold together with air. A nonwoven fabric is disclosed. Further, in order to manufacture a nonwoven fabric having a complicated three-dimensional structure such as an automobile seat cushion, there is a method in which the seat cushion is divided into parts having a simple shape and then manufactured, and then assembled. .

[0003]

However, Japanese Patent Laid-Open No. 6-2 / 1994
In the blow molding method disclosed in Japanese Patent No. 94061, it is difficult to make the density distribution of the seat cushion, which is a molded product, uniform. The obtained nonwoven fabric becomes heavy. In addition, in the method of cutting and pasting a nonwoven fabric, a seat cushion having a complicated shape has many small parts and the production cost rises sharply.

Further, the seat cushion material for automobiles has a vehicle interior temperature that rises to 70 to 100 ° C. when the door is closed under direct sunlight in summer, so that the recovery rate after a long-term load is applied in a high-temperature atmosphere. Improvement is required. In addition, since mattress materials for beds are subjected to washing treatment and disinfection treatment at a high temperature in a stacked state, it is required that the mattress materials are not deformed by swelling and compression after applying a load in a high temperature atmosphere. .

[0005]

Means for Solving the Problems In order to solve the above problems, the invention according to claim 1 of the present invention is a nonwoven fabric structure formed by bonding a large number of fiber masses made of short fibers, The fiber mass is composed of a matrix fiber and a binder fiber, and the fiber mass substantially adheres at a part of a mutual contact portion, and the short fibers constituting the fiber mass are in at least two planes of the fiber mass. A nonwoven fabric structure characterized by being arranged in random directions.

[0006] The invention according to claim 2 is the nonwoven fabric structure according to claim 1, wherein the fiber mass contains fibers to which a silicone oil agent has been applied.

The invention according to claim 3 is characterized in that the repulsive stress of the fiber mass at the time of 25% compression is 0.1 to 30 × 10 ^-2 kgf.
3 / cm ² ./cm 2.
It is a nonwoven fabric structure of the description.

According to a fourth aspect of the present invention, the first heat fusion state forming the fiber mass and the second heat fusion state fusing the fiber mass are structurally different from each other. The nonwoven fabric structure according to any one of claims 1 to 3, wherein a relation of primary heat-fused portion volume> secondary heat-fused portion volume is satisfied.

Further, the invention according to claim 5 is the nonwoven fabric structure according to any one of claims 1 to 4, wherein the fiber mass is a polyester fiber.

[0010] The invention according to claim 6 is that the short fibers are pre-spread by a pre-spreading machine, and then the short fibers are automatically piled up in a vertically low portion using an air flow. Is deposited, and a first heat-sealing process is performed.
A non-woven fabric is formed by performing the next heat fusion, and the non-woven fabric is formed into a fiber mass smaller than at least the non-woven fabric, and after the fiber mass is formed into a desired shape, a second fusion is performed by a heat fusion process. It is a nonwoven fabric structure.

According to a seventh aspect of the present invention, the short fibers are pre-spread by a pre-spreading machine, and then are automatically piled up in a vertically low portion using an air flow. Is deposited, and a first heat-sealing process is performed.
A non-woven fabric is formed by performing the next heat fusion, and the non-woven fabric is formed into a fiber mass smaller than at least the non-woven fabric, and after the fiber mass is formed into a desired shape, a second fusion is performed by a heat fusion process. This is a method for producing a nonwoven fabric structure.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a nonwoven fabric structure mixed with a lump polyester of the present invention and a method for producing the same will be described based on examples. The nonwoven fabric structure is formed by bonding a large number of crushed fiber masses of a nonwoven fabric having short fibers as constituent fibers. Hereinafter, the constituent fibers, the nonwoven fabric, the fiber mass, and the nonwoven fabric structure will be described in this order.

<Constituent Fiber> The short fibers constituting the nonwoven fabric structure comprising a large number of fiber masses of the present invention include at least a matrix fiber and a heat-fusible binder fiber,
Particularly, the heat-fusible binder fiber is 5% by weight of the nonwoven fabric structure.
Preferably, it is contained in an amount of up to 80% by weight. 5% by weight to 80
In the case of a content of weight%, the heat-fusible binder fiber is heat-sealed at a part of the intersection with the constituent fiber intersecting with the binder fiber, and stabilizes the fiber mass and the nonwoven fabric formed into a predetermined shape. It is good.

The matrix fibers include, but are not limited to, thermoplastic synthetic fibers, semi-synthetic fibers such as rayon, and natural fibers such as cotton. When thermoplastic synthetic fibers are used, for example, polyolefins such as polypropylene and polyethylene, polyesters such as polyethylene terephthalate and polybutylene terephthalate, polyamides such as nylon 6 and nylon 66, and copolymers thereof can be used. . Further, a mixture of two or more of these fibers may be used.

As the binder fiber, a copolymer or a blend polymer, for example, a copolymer whose melting point is lowered by a copolymer component such as isophthalic acid, or a heat-sealing polymer such as a blend polyester is preferably used.

The fiber mass is subjected to a first heat fusion treatment, and the nonwoven fabric structure is subjected to a second heat fusion treatment. The heat fusion treatment is performed at a temperature lower than the melting point of the matrix fiber and higher than the temperature at which the binder fiber exhibits the fusibility. By such heat fusion treatment, the constituent fibers intersecting with the binder fibers adhere at the intersections to impart morphological stability to the fiber mass and the nonwoven fabric structure, and the binder fibers cooperate with the support function of the matrix fibers to form the fiber mass and the nonwoven fabric structure. Gives moderate rigidity to the body. Furthermore, the use of the binder fiber makes it possible to absorb irregularities attached to the surface of the fiber mass and the nonwoven fabric structure, or to intentionally impart irregularities to the surface of the nonwoven fabric.

The binder fiber may be a single-component fiber made of the above-mentioned heat-fusible polymer, but a sheath-core conjugate fiber having a low-melting polymer for the sheath component and a higher-melting polymer for the core component is used. It is more preferable if the heat-sealing function can be performed while maintaining the support function of the core component. As such a binder fiber, a normal polyethylene terephthalate polymer as a core component,
Although those having a low melting point copolymerized polyethylene terephthalate polymer as a sheath component are known, the invention is not limited thereto. In addition, the temperature at which the binder fiber exhibits the fusibility is:
When the matrix fiber is mainly composed of polyester, the softening point of the binder fiber of the copolymerized polyester is 9
A binder fiber made of a highly crystalline copolymerized polyester having a predetermined clear melting point at 0 ° C or more, preferably 130 to 200 ° C, is desirable from the viewpoint of heat resistance.

Other than that, there is no particular limitation on the material of other fibers to be mixed to newly impart functionality. What is necessary is just to select suitably according to a use. Common synthetic fibers, natural fibers,
Semi-synthetic fibers can be used.

<Nonwoven Fabric> The fiber mass constituting the nonwoven fabric of the present invention will be described. The fiber mass is produced by crushing a special nonwoven fabric. Therefore, this special nonwoven fabric will be described first. The nonwoven fabric is a thin rectangular parallelepiped, and the orientation of the fibers on at least two surfaces of the rectangular parallelepiped is random. The feature of this nonwoven fabric is that it is manufactured by a manufacturing apparatus and a manufacturing method using the manufacturing apparatus described in detail below. Here, the orientation of the fibers on at least two surfaces thereof is random (hereinafter, referred to as , "3D randomness").

The three-dimensional randomness refers to the directionality (also called orientation) of the fibers of each fiber constituting the nonwoven fabric.
Are not aligned in a certain direction. In order to quantify this randomness, three-dimensional randomness was defined by the following procedure.

First, at least two of the rectangular parallelepiped nonwoven fabric
A sample (about 2 cm × 2 cm) for the surface is set in a stereo microscope, and the image data is taken into an image processing apparatus (an image analyzer V10 manufactured by Toyobo Co., Ltd.) at a magnification of about 40 times. Next, the image data of this original image is represented by T
"Binarization processing" by the OKS method is performed, and the fiber portion is divided into two, with a black portion and a background portion being a white region. Further, "thinning processing" is performed on the background portion (white area) to make the thickness uniform. The direction of this background is referred to as “fillet diameter ratio (y /
x ratio), and the average value (average value of about 10 data) is defined as quantified three-dimensional randomness as an index indicating the directionality of the fiber of the nonwoven fabric itself.

The fillet diameter is one type of image processing command in the image processing apparatus, and performs the following processing. Each fiber constituting a nonwoven fabric in which the background portion (white area) in the image data is subjected to "thinning processing" and the thickness is made uniform, with the horizontal axis being the X axis and the vertical axis being the Y axis in the image processing apparatus. , The length of the projected horizontal diameter on the X axis, which is the horizontal axis, is defined as the fillet diameter X.
The length of the projection vertical diameter on the Y axis, which is also the vertical axis, is calculated as the fillet diameter Y. This calculation process is performed for each fiber, and the calculation result is defined as a fillet diameter ratio, and the fillet diameter ratio (y / x
Ratio). The fillet diameter ratio calculated in this way is 1.00 if the directionality is completely random.
When the directionality is inclined to the X axis, it becomes 1.00 or less. Conversely, when tilted to the Y axis, it becomes 1.00 or more. As described above, the fillet diameter ratio is determined for each fiber and the average value thereof is obtained, whereby the fillet ratio close to 1.00 has randomness. By performing this process on at least two surfaces of the rectangular parallelepiped of the nonwoven fabric, if the fillet diameter ratio on each surface is close to 1.00, it can be said that three-dimensional random.

Table 2 and Table 3 show the fillet diameter ratios of the non-woven fabric according to the present invention (Example 1) and the non-woven fabric manufactured by the card method as a comparative example. (See Table 1 for production conditions such as fineness and fiber length of each nonwoven fabric.)

[0024]

[Table 1]

[0025]

[Table 2]

[0026]

[Table 3]

As is clear from Tables 2 and 3, the fillet diameter ratio of the nonwoven fabric according to the present invention is close to 1.00, whereas that of the nonwoven fabric manufactured by the card method is lower than 1.00. The difference is expressed. Therefore, the fact that the degree of fiber orientation in at least two planes of the nonwoven fabric is in the range of 0.95 to 1.05 can be defined as having three-dimensional randomness.

Next, the results of the performance evaluation of the nonwoven fabric according to the present invention will be shown. The performance evaluation was a sound absorbing characteristic when this nonwoven fabric was used as a sound absorbing material.
000 Hz) and a static spring constant at 5 kgf. The results are shown in Table 4.

[0029]

[Table 4]

The sound absorbing properties and mechanical properties shown in Table 4 were measured as follows. Sound absorption coefficient is JIS-A1405
Incident sound absorption coefficient according to Bruel & Kjar
The measurement was performed by a two-microphone method using a multichannel analysis system Model 3550 (software: Model BZ5087, two-channel analysis software) manufactured by KK. The measurement range is 0 to 5000 Hz and N = 8. The static spring constant at 5 kgf was measured by an automatic hardness tester according to JASO-M304. 300x300m which is a measurement sample
20 mm and a thickness of 50 mm
The thickness when a load of 0.5 kgf is applied by a 0 mm pressing plate is defined as the initial thickness. This is applied at a pressing speed of 50 mm / min from 0 to 6
Compress to 5%, and measure the static spring constant at 5 kgf. The lower the static spring constant, the lower the frequency range (500 to 10).
(00 Hz).

As is evident from Table 4, there is a remarkable difference in the sound absorption characteristics between the nonwoven fabric manufactured by the conventional card method and the nonwoven fabric according to the present invention. The first reason for expressing this difference is that ultra-fine fibers, which could not be applied to a carding machine with a conventional nonwoven fabric and could not be used as a constituent fiber of the nonwoven fabric, became fibers of a nonwoven fabric per unit volume. This is because the total surface area was increased. That is, sound absorption occurs when sound waves (waves of air molecules) enter the nonwoven fabric and come into contact with the surface of the fiber to convert sound energy into heat energy due to friction. For this reason, if the nonwoven fabric has the same basis weight, the lower the average denier, the more the number of fibers per unit volume increases, the total surface area increases, the conversion of heat energy of sound waves increases, and the sound absorption characteristics improve. . Conventionally, an ultrafine fiber of about 0.5 denier, which has not been applied to a card machine, has exhibited such an effect.

The second reason is expressed by three-dimensional randomness that cannot be realized by a conventional nonwoven fabric. That is, by having three-dimensional randomness,
It is considered that the diffuse reflection of the propagating sound wave in the nonwoven fabric was promoted, so that multiple reflection of the sound proceeded, and the friction between fibers became more likely to occur, so that the sound absorption characteristics were improved. It should be noted that JP-A-10-1
Japanese Patent No. 10370 describes a two-dimensional random manufactured by blow-molding after hanging on a card machine, which has an orientation in a fiber traveling direction in the card machine due to the characteristics of the card machine. The improvement in sound absorption characteristics is not so expected.

Considering from a macro perspective, 3
If the dimension is random, the sound absorbing material as a whole has three-dimensional degrees of freedom. Such a point has a characteristic that the two-dimensional one does not propagate between layers with respect to the incidence of sound from the stacking direction (that is, if the sound incidence direction and the stacking direction are parallel to each other, the sound is lost and the sound absorption characteristics are reduced). In the case of three dimensions, it also has a characteristic that a desired sound absorption characteristic can be obtained regardless of the incident direction. In other words, it is considered that the direction of the reaction of the force received by the propagation of the sound is not uniform in the entire fiber assembly, so that the sound absorption characteristics are improved as compared with the case of the two-dimensional random.

The non-woven fabric before crushing can be subjected to a heat treatment. This heat treatment is referred to as a first heat fusion treatment, and is distinguished from a second heat fusion treatment, which is a heat fusion treatment for performing a heat fusion treatment on a fiber mass to form a nonwoven fabric structure.
The first heat fusion treatment is performed at a temperature lower than the melting point of the matrix fiber and higher than the temperature at which the binder fiber exhibits the fusibility. By such a primary heat fusion treatment, the constituent fibers that intersect with the binder fibers inside the fiber mass adhere at the intersections to impart morphological stability to the fiber mass itself, and the binder fibers cooperate with the support function of the matrix fibers. Providing moderate rigidity to the fiber mass itself.

<Fiber lump> The nonwoven fabric produced in the above process is
Crushing is performed using a square pelletizer or a rotary universal crusher to obtain a fiber mass having a desired size. However, the crushing of the nonwoven fabric is not limited to the crusher described above. In addition, the rotary universal crusher has good productivity,
While the fibers are slightly damaged, those crushed using a square pelletizer have no damage to the fibers and have good repulsion.

As a characteristic of the fiber mass, the shape is the major axis-
It is preferable that the difference in the minor axis is small, and the minor axis is 2 to 100 m.
m More preferably, a shape of 5 to 20 mm is preferable. If the shape has a large difference between the major axis and the minor axis, the moldability is poor, which is not preferable. 0.1 to 30 × rebound stress at 25% compression
10 ⁻² kgf / cm ² is preferable, and 1.0 to 10 ×
10 ⁻² kgf / cm ² is particularly preferred.

<Non-woven Fabric Structure> The non-woven fabric structure of the present invention has a structure in which the above-mentioned fiber mass is formed into a desired shape and then subjected to a second heat fusion treatment to heat-weld the fiber mass. As for the shape, it is preferable that the average thickness of the main body portion excluding the end portion and the special portion of the mounting portion in use is 5 mm or more. When the average thickness is 5 mm or more, sufficient rigidity as a support can be maintained, and a feeling of fixation, a sense of stability, and cushioning properties are obtained.

Further, the average density of the nonwoven fabric is 0.01 to
It is preferably 0.50 g / cm ³ . When the content is within this range, sufficient strength as a support can be obtained, and a good tactile sensation and appropriate cushioning properties can be obtained.

The form based on the second heat fusion treatment of the fiber mass forming the nonwoven fabric structure will be described. Fiber clumps are those in which the fiber clumps are in close contact with each other under the condition of being formed into a desired shape by the second heat fusion treatment, and the fiber clumps are bonded by the thermal fusion of the binder fiber which is a constituent fiber. Becomes

Therefore, when the first heat fusion treatment is performed before the fiber mass is formed, the nonwoven fabric structure according to the present invention has the inside of the nonwoven fabric structure based on the first heat fusion treatment. It has the feature that the form and the fusion form based on the second heat fusion process coexist. In the first heat fusion mode, the second heat fusion processing is also added, and the melting intersection of the binder fibers has a characteristic that the first heat fusion part volume> the second heat fusion part volume, and further, Indicates that the primary heat fusion mode has a nodular shape. Second
The next hot-melt form is characterized by the bonding of fiber masses. It is considered that such a form produces a remarkable improvement in cushioning properties.

Next, the results of the performance evaluation of the nonwoven fabric structure according to the present invention will be shown. Performance evaluation was evaluated based on the residual strain rate, which is the recovery rate when the load is applied to the upper surface of the sample for a certain period of time under a certain condition and then removed, which is the recovery characteristic against a compressive load when this nonwoven fabric is used as a cushioning material. . Table 5 shows the results.

(Method of Measuring and Evaluating Recovery under Normal Temperature Atmosphere) A sample was cut out to 10 cm × 10 cm.
Measure the initial thickness. Thereafter, the sample is sandwiched between iron plates and compressed to 50% of the initial thickness. 22 ° C, 65%
Leave at RH for 15 hours. After being left for 15 hours, the weight is removed, the thickness after compression is measured, and the strain rate is calculated from the following equation.

Strain rate (%) = (initial thickness-thickness after compression)
/ Initial thickness × 100 Evaluation: Strain rate less than 5% ○, 5% or more and less than 15% △,
15% or more was evaluated as x.

(Method of Measuring and Evaluating Recoverability Under High Temperature Atmosphere) A sample was cut out to a size of 10 cm × 10 cm.
Measure the initial thickness. Thereafter, the sample is sandwiched between iron plates and compressed to 50% of the initial thickness. 70 ° C in the dryer as it is
And leave for 15 hours. After being left for 15 hours, the weight is removed, the thickness after compression is measured, and the strain rate is calculated from the following equation.

Strain rate (%) = (initial thickness-thickness after compression)
/ Initial thickness × 100 Evaluation was evaluated as ○ when the distortion rate was less than 25%, Δ when it was 25% or more and less than 35%, and X when it was 35% or more.

(Measurement method and evaluation method of cushioning property) A sample was cut out to a size of 30 cm × 30 cm, and an automatic hardness tester “ASKAR AF200” manufactured by Kobunshi Keiki Co., Ltd.
Compresses and unloads to 65% of the initial thickness at a constant speed of 50 mm / min with a disc having a diameter of 200 mmφ, and measures the SS curve at that time. The evaluation was evaluated as ○ when the hardness at 25% compression was 10 kgf or more and less than 20 kgf, Δ when the hardness was 20 kgf or more and less than 30 kgf, and × when the hardness was less than 10 kgf or 30 kgf or more. When it is 10 kgf or more and less than 20 kgf, when it is used for a cushion material for a seat of an automobile or the like, an appropriate cushioning property is obtained. Also, excessive compression deformation of the cushioning material due to load fluctuation is suppressed, and the feeling of bottoming is reduced, which is particularly preferable.

[0047]

[Table 5]

As is apparent from Table 5, the compression distortion rate is
There is a remarkable difference between the nonwoven fabric manufactured by the conventional card method and the nonwoven fabric according to the present invention. The reason for expressing this difference is that the fiber mass becomes a component of the nonwoven fabric structure, the fiber mass is bonded to each other at a desired contact point, and that the fiber mass has a predetermined compressive stress. Expression.

FIG. 1 shows a schematic diagram of such a nonwoven fabric structure. As shown in FIG. 1, the nonwoven fabric structure of the present invention comprises:
It has a composite structure of the support function by the binder fiber inside the fiber mass and the support function by adhesion of the fiber mass.

That is, when a load is applied under a high temperature, from the microscopic viewpoint, the binder fiber inside the fiber mass has an appropriate rigidity to the fiber mass itself in cooperation with the support function of the matrix fiber. Therefore, a load is applied inside the fiber mass. From a macro perspective, the repulsion between the fiber masses is developed by randomly arranging the fiber masses inside the structure, and the repulsion and stress caused by the reduction of the internal stress due to the repulsion. It is considered that dispersibility, elastic recovery and compression durability are improved.

Also, by blending the cotton with silicon, the degree of freedom after debulking is increased due to the decrease in the friction coefficient between the fibers, and the random arrangement of the fiber mass increases the three-dimensional degree of freedom of the cushion material as a whole. It is considered that such a three-dimensional degree of freedom provides excellent shape recovery after degraving. In other words, the direction of the reaction of the force received from the load as a whole of the nonwoven fabric aggregate becomes non-uniform,
It is considered that the recovery characteristics are improved as compared with the case of the laminate.

Further, since the fiber mass itself has a desired coefficient of restitution, even if the fiber mass is blow-molded, for example, it can be avoided that the fiber masses are crushed to each other and it is difficult to control the desired density. In addition, it is considered that the fiber lump itself has an appropriate bonding point, and the fiber lump itself has many bonding points, so that the shape stability of the nonwoven fabric structure is improved.

In particular, nonwoven fabric structures which have been subjected to primary and secondary heat-sealing treatments with wet heat using highly crystalline thick denier core-sheath type binder fibers have remarkably favorable evaluations. This is because, in addition to the above-mentioned reasons, as is apparent from the electron micrograph shown in FIG. 2, the binder fiber has a crossing point between the crossing point between the binder fiber and the binder fiber or between the binder fiber and the other constituent fiber. In the meantime, a portion thicker than the binder fiber before the heat fusion treatment appears as a node.

This section is manifested simply by increasing the temperature,
In this case, it is necessary to make the temperature considerably higher than the melting point of the highly crystalline binder fiber (for example, 30 to 50 ° C.), so that the polyester fiber which is the main fiber of the matrix and the regular polyester of the core of the core-sheath type binder fiber due to the high temperature. There is a disadvantage that heat deterioration easily occurs. Therefore, by performing the wet heat fusion treatment at 160 ° C. for 10 minutes using the above-mentioned binder fiber, the effect is more effectively exhibited.

As a result, when focusing on one binder fiber and observing it, at the intersection, a cross-shaped melting point is used as an adhesion point, and between the next intersection, a portion consisting of only the core portion,
It has a shape (hereinafter referred to as a knot-like structure) in which the sheath portion starts flowing due to overmelting and the sheath portion becomes a ball in the core portion.

As described above, when the nonwoven fabric structure according to the present invention has a knot-like structure therein, the constituent fibers intersecting with the binder fibers adhere at the intersections to impart shape stability to the nonwoven fabric structure. . The binder fibers cooperate with the support function of the matrix fibers to provide the nonwoven structure with adequate rigidity. In addition, for loads under severe conditions, not only the heat fusion point at the intersection, but also the composite structure form consisting of a knotted structure with a sheath melted at the core and the core before and after it is remarkable It develops various forms of resilience.

That is, even when a compressive load is applied in an atmosphere at or above the glass transition point of the low melting point polymer, after the release of the load, the node-shaped portions are not uniformly and uniformly thickened in places. Is considered to have a different rigidity from a structure having a uniform thickness. On the other hand, it is presumed that the node-like structure not only provides rigidity but also functions like a spring structure.

Further, since the directionality of the short fibers constituting the fiber mass has a random direction on at least two sides, as apparent from Table 5, the compressive strain rate is determined by the conventional nonwoven fabric structure manufactured by the card method. There is a significant difference between the body and the nonwoven structure according to the invention. The reason for expressing this difference is that the fiber mass is a constituent element of the nonwoven fabric structure, and the orientation of the constituent fibers inside the fiber mass is a three-dimensional random arrangement structure. Is expressed. In other words, when a load is applied under high temperature, from the microscopic viewpoint, the binder fibers inside the fiber mass are given an appropriate rigidity to the fiber mass itself in cooperation with the support function of the matrix fiber. Therefore, a load is received at this portion.
Considering from a macro perspective, the state in which the fiber masses inside the structure are arranged three-dimensionally at random causes the repulsion of the fiber masses to develop, and the internal stress is reduced by the repulsion. It is considered that resilience, stress dispersibility, elastic recovery and durability are improved. In addition, 3
It is considered that the cushion material as a whole has three-dimensional degrees of freedom due to the arrangement of the fibers in a three-dimensional manner, and the three-dimensional degrees of freedom provide excellent shape recovery after deloading.
In other words, it is considered that the direction of the reaction of the force received from the load becomes non-uniform as a whole of the aggregate of the nonwoven fabric, so that the recovery characteristics are improved as compared with the two-dimensional random case.

Next, an apparatus for manufacturing such a nonwoven fabric structure according to the present invention and a manufacturing method using the apparatus will be described in detail.

(Nonwoven Fabric Manufacturing Apparatus) The fiber mass constituting the nonwoven fabric structure according to the present invention is manufactured by manufacturing a nonwoven fabric and then crushing the nonwoven fabric. An example of this nonwoven fabric manufacturing apparatus is shown in FIGS.

As shown in FIGS. 3 and 4, the nonwoven fabric manufacturing apparatus includes an input duct (1) for inputting the pre-opened fibers, an exhaust duct for exhaust air (2), and air in the reserve trunk (4). Outlet 1 (3), a reserve trunk (4) for temporarily storing short fibers, a feed roller (5) for sending short fibers from the reserve trunk (4) to an opener roller (6), an opener for opening fibers and sending them to the feed trunk Roller (6), feed trunk (7) for feeding short fiber to delivery roller (9) by a fixed amount, air outlet 2 (8) in feed trunk (7), delivery roller (9) for feeding web (W) from the device. , A fan that blows air to each part of the apparatus, and a conveyor (10) that transports the web (W) to the subsequent process. The air flow is indicated by white arrows, and the fiber flow is indicated by black arrows.

The nonwoven fabric manufacturing apparatus will be described in detail for each mechanism.

<Input Duct> The input duct (1) is a hollow rectangular parallelepiped located above the apparatus and having an opening at the side or above. This is a section where fibers (tufts) preliminarily opened by an air flow are conveyed and introduced into the apparatus.

<Exhaust Duct> The exhaust duct (2) is a duct located near the input duct and having an opening at the top. The exhaust duct (2) controls the air flow used for transporting the fibers (tufts) when the apparatus is input. This is a duct that discharges to the outside of the device.

<Air Outlet 1> The air outlet 1 (3) is, for example, a punching metal or a rectangular perforated plate having a large number of small diameters formed in a flat plate, and has a structure in which the area of the opening can be adjusted. It is composed of things. Further, as a measure against fly waste, a filter or the like is provided before discharging to the outside of the apparatus.

<Reserve Trunk> The reserve trunk (4) has a vertical cylindrical shape for storing pre-spread fibers (tafts), and has a feed roller (5) below the reserve trunk. Is provided. The fiber (taft) is temporarily stored in the reserve trunk (4), and is opened by the feed roller (5) and the opener roller (6).
Sent to.

<Feed Roller> The feed roller (5) is installed at the bottom of the reserve tank (4). A tooth wire is wound around the feed roller (5), the diameter thereof is large, and the length thereof is designed to be about 50 to 100 mm longer than the width of the web (W). With such a configuration, the raw material can be reliably sent out even to a raw material having a high bulkiness or a raw material having a long fiber length. Further, a motor capable of variable speed control, for example, an AC motor controlled by an inverter is connected to the feed roller (5) via a speed reducer. The speed control is based on the weight data of the web (W) from the weight checker for detecting the weight of the web (W) provided at the apparatus outlet or the sensor from the sensor for detecting the height of the web (W) provided at the apparatus outlet. Feedback control is performed based on the height data of the web (W) so that the weight and thickness of the web (W) always become set values. The weight or thickness of the web (W) is controlled by performing feedback control based on pressure data measured by a pressure sensor provided in the feed trunk (7) so that the pressure in the feed trunk (7) is always constant. Is preferably set to a set value.

<Opener Roller> The opener roller (6) is installed near the lower part of the feed roller (5). The surface of the opener roller (6) is provided with several rows of spikes, the length of which is web (W)
Is designed to be about 50 to 100 mm longer than the width. Further, an electric motor rotating at a constant speed is connected to the opener roller (6) via a speed reducer. By the interaction between the opener roller (6) rotating at a constant speed and the feed roller (5) rotating at a variable speed, the fiber (tuft) is sufficiently opened and supplied to the feed trunk (7). .

<Feed Trunk> The feed trunk (7) has an opener roller (6) at its upper part, has a delivery roller (9) at its lower part, and has an air outlet 2 (8) at its middle part. It is a hollow rectangular parallelepiped. The fiber (tuft) supplied from the opener roller (6) is deposited in the feed trunk (7) by the manufacturing method described later so as to be uniform in the width direction, and becomes a web (W).

<Air Outlet 2> The air outlet 2 (8) is installed below the walls before and after the feed trunk (7), and is, for example, a punched metal or a rectangular hole having a large number of small diameters formed in a flat plate. It is composed of a perforated plate or the like having a structure in which the area of the opening can be adjusted. These are provided over the entire width of the device.

<Delivery Roller> The delivery roller (9) is composed of, for example, two rollers opposed in the horizontal direction, and the length thereof is set to be about 50 to 100 mm longer than the width of the web (W). Designed for Furthermore, this delivery roller (9)
An electric motor rotating at a constant speed is connected via a speed reducer. The web (W) deposited in the feed trunk (7) is discharged out of the apparatus by two opposing delivery rollers (9).

<Transport Conveyor> Transport Conveyor (10)
Is, for example, a known belt conveyor for discharging a web (W) manufactured on an upper surface thereof horizontally out of the apparatus.

(Method for Producing Nonwoven Fabric) In the nonwoven fabric structure according to the present invention, the pre-spread short fibers are vertically deposited using an air flow, and the nonwoven fabric produced by extruding with the horizontal direction after the extrusion is crushed. This is obtained by heat-fusing a large number of fiber masses.

The method for producing the nonwoven fabric will be described in detail in the order of the steps.

<Preliminary Fiber Opening Step> The fiber (taft) taken out of the raw cotton by the bale opener is gradually and finely and uniformly made uniform by the opener generally used in the blended cotton step and the like. These openers are provided with a beater, a cylinder, a spike roller, a tooth roller, and the like, and the roller mechanism and the like sufficiently open the short fiber composition. In order to produce a uniform web (W), the fibers (tufts) must be sufficiently opened, and the opening ratio is preferably 95% or more.

<Air Transport Step> The opened fiber (tuft) is transported from the opener to the input duct (1) of the manufacturing apparatus of the present invention by air.

<Reserve process> Input duct of device (1)
The fibers (tufts) supplied from the above are temporarily retained in the reserve trunk (4). In the reserve trunk (4), the air flow rate is controlled so as to adjust the flow rate of the air flowing into the reserve trunk (4) and to keep the filling height and the filling density in the reserve trunk (4) constant. That is, when the pressure in the trunk duct increases due to an increase in the level of the fiber (taft) or its density in the reserve trunk (4), this pressure fluctuation is detected and the air flow from the fan is reduced to reduce the amount of cotton feed. Let it. Conversely, when the pressure in the trunk duct decreases in accordance with the decrease in the level or density of the fiber (tuft), this pressure fluctuation is detected and the air flow from the fan is increased to increase the cotton supply. By performing such control, the operation is not stopped, and the filling level is kept constant. This air volume adjustment is performed by controlling the number of rotations of a fan provided at the center of the device, by changing the opening area of the air outlet 1 (3), and the like.

<Feeding Step> Next, fiber (tuft)
Are fed into the feed trunk (7). In this case, a feed roller (5) is provided at the bottom of the reserve tank (4), and the web (W) is supplied to the opener roller (6) through the feed roller (5). As described above, the tooth wire is wound around the roller (5), and since the diameter thereof is set to be large, the raw material is reliably sent out even to a raw material having a high bulkiness or a long fiber length. be able to. The feed roller (5) detects the pressure in the feed trunk (7) and the speed is controlled. Further, since the speed of the opener roller (6) is constant and the circumference is provided with several rows of spikes, the fibers (tufts) are further homogenized and supplied to the feed trunk (7). . The web (W) in the feed trunk (7) is uniformly compressed in the width direction by the air flow generated by the fan inside the device, and the air flow is compressed by the air outlet 2. After (8), it is controlled to return to the fan. By doing so, the depth of the web (W) can be made constant along with the density of the web (W) deposited in the feed trunk (7). Since the web (W) in the feed trunk (7) is very small, it is not compressed under its own weight. Although the web (W) is compressed by the air flow from the fan, the speed of the feed roller (5) is controlled so that the compression pressure is constant. That is, the speed is reduced with an increase in the internal pressure of the feed trunk (7), that is, the supply amount of fiber (tuft) is reduced, and the speed of the feed roller (5) is increased by a decrease in the internal pressure, that is, the supply amount of fiber (tuft) is reduced. To raise. The fibers (tufts) discharged from the opener roller (6) are automatically directed by the airflow of the fan to a portion where the raw material level in the feed trunk (7) is low, that is, a portion where the flow resistance of the air is low. . This makes the feed trunk (7)
Raw material level differences can be eliminated over the entire width of the device within, ultimately resulting in high uniformity across the web (W). Also, as described above, the web (W)
Instead of controlling the thickness of the material by the change in air flow generated from the deviation in the width direction, the raw material that has progressed is weighed by an automatic weighing system such as a load cell system, and the raw material of an arbitrarily set weight is deposited based on the actual measurement value Alternatively, the raw material having an arbitrarily set weight may be deposited while beating the fiber (taft) with a beater instead of an air flow.

<Discharge Step> The fibers (tufts) in the feed trunk (7) are sent out of the apparatus by the delivery roller (9). The discharged web (W) is transported to a subsequent process by the transport conveyor (10).

<First heat fusion treatment step> First, in the case of a nonwoven fabric (W) containing heat fusion fibers, it is set on a heat setter. The heat setter is a known device. For example, a web (W) is placed on a conveyor or the like in a device having a heat source.
Has a structure to pass through. Examples of the heat source include hot air obtained from combustion gas, high-temperature steam, far infrared rays, and the like. The temperature of the heat setting is a temperature at which the low melting point component is melted and the high melting point component is not melted. By the treatment in this first heat fusion treatment step, the low melting point component is melted and substantially fused at the contact point with the high melting point component.

In the case of a nonwoven fabric (W) containing heat-fusible fibers, a wet heat setter is set in addition to or in place of the above-mentioned processing method. This wet heat setter is a known device, and after the nonwoven fabric (W) is charged into the inside of the steam pot, the steam pot is closed and the pressure is reduced.
It has a structure to send high pressure and high temperature wet heat steam. The temperature of the heat setting is a temperature at which the low melting point component is melted and the high melting point component is not melted. By the treatment in the first heat fusion treatment step, heat can be transmitted to the inside of the nonwoven fabric (W), and the low melting point component is melted at every corner of the nonwoven fabric (W), and substantially at the contact point with the high melting point component. It will be fused. According to such a method, even if several nonwoven fabrics (W) transported by the transport conveyor (10) are stacked and processed, steam can penetrate into the inside thereof, and uniform heat setting can be performed. When several nonwoven fabrics (W) are stacked in this manner, nonwoven fabrics having different fiber densities in the thickness direction can be easily manufactured by stacking nonwoven fabrics having different fiber densities. In any case, it is suitable for manufacturing a cushion material or the like.

<Production of Nonwoven Fabric 1> Hollow conjugate polyester fiber 6 denier was used as matrix fiber.
80% by weight of 51 mm, as binder fiber, 2 denier of binder polyester fiber having a melting temperature of 110 ° C.,
51 mm was mixed at 20% by weight to obtain a non-woven fabric in the above-described non-woven fabric manufacturing process, and lightly entangled with a needle punch to obtain a non-woven fabric 1 having a thickness of 20 mm and a basis weight of 500 g / m ² .

<Production of Nonwoven Fabric 2> Hollow conjugate polyester fiber 6 denier as matrix fiber,
As a binder fiber, 51 mm is 80% by weight, and 2 deniers of binder fiber using a copolyester having a melting temperature of 110 ° C. as a sheath and 51 mm are mixed at 20% by weight. An infrared heat fusion treatment was performed as a next heat fusion treatment to obtain a nonwoven fabric 2 having a thickness of 30 mm and a basis weight of 500 g / m ² . The conditions of the first heat fusion treatment are as follows: upper heater 250 ° C., lower heater 350 ° C.
It is.

<Production of Nonwoven Fabric 3> As a matrix fiber, 6 denier hollow conjugate polyester fiber was used.
50% by weight of 51 mm, cotton 6 denier with silicon, 5
30% by weight of 1 mm, 2 denier core-sheath type binder fiber having a melting temperature of 110 ° C. used as a sheath, and 51 mm of 20% by weight were mixed as binder fibers, and the non-woven fabric was formed in the non-woven fabric manufacturing process described above. As a first heat fusion treatment, an infrared heat fusion treatment was performed to obtain a nonwoven fabric 3 having a thickness of 30 mm and a basis weight of 500 g / m ² . The conditions of the first heat fusion treatment are as follows: the upper heater 250 ° C., the lower heater 350
° C.

<Production of Non-woven Fabric 4> Hollow conjugate polyester fiber 6 denier was used as matrix fiber.
As a binder fiber, 51 mm of a core-sheath type binder fiber using a highly crystalline polyester having a melting temperature of 160 ° C. as a sheath, and 51 mm, and 20% by weight of 51 mm were mixed as binder fibers. A nonwoven fabric 4 having a thickness of 20 mm and a basis weight of 500 g / m ² was obtained by confounding with a needle punch.

<Manufacture of Nonwoven Fabric 5> Hollow conjugate polyester fiber 6 denier as matrix fiber,
80% by weight of 51 mm, as binder fibers, 15 deniers of binder fibers using a high crystalline polyester having a melting temperature of 160 ° C. as a sheath and 20% by weight of 51 mm were mixed.
After forming the nonwoven fabric in the nonwoven fabric manufacturing process described above, an infrared heat fusion process is performed as a first heat fusion process to a thickness of 30 mm.
A nonwoven fabric 5 having a basis weight of 500 g / m ² was obtained. The conditions of the first heat fusion treatment are as follows: upper heater 350 ° C., lower heater 45
0 ° C.

<Production of fiber mass> The nonwoven fabrics 1 and 4 produced in the above step were crushed using a square pelletizer, and had a size of 8000 mm ³ and a rebound stress at 25% compression of 5 × 10 ^-2 kgf / cm. A fiber mass of ² was obtained. Also, the first
The non-woven fabrics 2, 3 and 5 subjected to the next heat fusion treatment were crushed by a rotary universal pulverizer manufactured by Sanriki Seisakusho, having a size of 1000 mm ³ and a rebound stress at 25% compression of 10 × 10 ^-2. A fiber mass of kgf / cm ² was obtained. The crushing of the nonwoven fabric is not limited to the crusher described above. The rotary universal crusher has high productivity, but the fiber is slightly damaged, but the one crushed by using a square pelletizer has no fiber damage and good repulsion.

<Production of Nonwoven Fabric Structure A> A mold (molding die) conforming to a desired shape is manufactured, and the fiber mass produced as described above is mixed and blown into the molding cavity of the mold. When filling the fiber mass into the mold, only the air for transportation is discharged from the exhaust port to the outside of the mold, and the fiber mass is efficiently filled in the mold.

Next, after filling the fiber mass, a second heat fusion treatment is performed. The heat fusion process is performed by blowing hot air generated by a hot air generator through a blowing pipe and a duct from a blowing port into the mold. At the same time, the press machine is operated to compress the filled fiber mass into a predetermined shape and size.

Further, even if superheated steam is blown into the mold instead of hot air drying, it is preferable in that uniform heat fusion can be performed without unevenness in temperature distribution. In this case, the condition of the second heat fusion treatment for the nonwoven fabric 1 is 13
0 ° C., and the condition of the second heat fusion treatment for the nonwoven fabric 4 is 190 ° C. The condition of the second heat fusion treatment for the nonwoven fabrics 2 and 3 is 110 ° C. in wet heat, and the condition of the second heat fusion treatment for the nonwoven fabric 5 is 160 ° C. in wet heat. Nonwoven fabric structures manufactured from fiber masses using nonwoven fabrics 1, 2, 3, 4, and 5 as raw materials are nonwoven fabric structures A1, A2,
A3, A4, and A5.

<Production of Nonwoven Fabric Structure B> The fiber mass produced as described above is weighed in batches, and a second heat-fusion process is performed for a desired weight. In this case, the condition of the second heat fusion treatment for the nonwoven fabric 1 is 130 ° C., and the condition of the second heat fusion treatment for the nonwoven fabric 4 is 190 ° C. The condition of the second heat fusion treatment for the nonwoven fabrics 2 and 3 is 110 ° C. in wet heat, and the condition of the second heat fusion treatment for the nonwoven fabric 5 is 160 ° C. in wet heat. Non-woven fabric 1,
The nonwoven fabric structures manufactured from the fiber masses made from 2, 3, 4, and 5 are nonwoven fabric structures B1, B2, B3, B4, and B, respectively.
5

[0092]

The structure of the nonwoven fabric according to the first aspect of the present invention is characterized in that a fiber mass of an unspecified shape is bonded to the constituent fibers by heat melting. In addition, in addition to the rigidity and cushioning property of the fiber lump itself, the rigidity and cushioning property of the fiber lump are provided, so that the fiber lump is suitable for use in automobiles and mats for beds.

The nonwoven fabric structure according to the second aspect of the present invention has a fiber mass containing fibers to which a silicone oil agent is applied, and has a degree of freedom after deloading due to a decrease in friction coefficient between the fibers. And the resilience, stress dispersibility, elastic recovery and durability are improved.

Further, in the nonwoven fabric structure according to the third aspect of the present invention, since the coefficient of restitution of the fiber mass is not less than a certain value, the fiber mass may be blown, crushed and pushed too much. And a uniform molded product.

The nonwoven fabric structure according to the fourth aspect of the present invention has a first heat-sealed form and a second heat-sealed form in its internal structure. The rigidity of the fiber mass itself is imparted in the secondary heat fusion mode, and the rigidity and the like of the fiber mass are imparted in the secondary heat fusion mode, exhibiting the desired effect, and even when a load is applied in a high temperature state for a long time. , Will exhibit behavior with excellent morphological stability

In the nonwoven fabric structure according to the fifth aspect of the present invention, the polyester is used as the main fiber, so that the recycling becomes easy.

Further, the nonwoven fabric structure according to the invention described in claim 6 is manufactured by subjecting a fiber mass to a desired shape and then performing a second fusion by heat treatment.

Further, according to the invention described in claim 7, a nonwoven fabric structure suitable for an automobile or a bed mat can be manufactured at low cost.

[Brief description of the drawings]

FIG. 1 is a schematic view showing a state of a nonwoven fabric structure according to the present invention.

FIG. 2 is an electron micrograph of a nonwoven fabric structure according to the present invention, which has been subjected to overheating.

FIG. 3 is a side view of an apparatus according to the manufacturing apparatus of the present invention.

FIG. 4 is a front view of an apparatus according to the manufacturing apparatus of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Input duct 2 Exhaust duct 3 Air outlet 1 4 Reserve trunk 5 Feed roller 6 Opener roller 7 Feed trunk 8 Air outlet 2 9 Delivery roller 10 Conveyor 11 Binder fiber 12 Matrix fiber 13 Intersection 14 Node structure T fiber (taft) W Web

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Mangeo Nagata 1-2-2 Umeda, Kita-ku, Osaka Kanebo Synthetic Fiber Co., Ltd. (72) Inventor Hiroharu Yoshida 1-2-2 Umeda, Kita-ku, Osaka Kanebo Synthetic Co., Ltd. F-term (reference) 4L047 AA21 AB02 BA09 BD01 CC07 CC09

Claims (7)

[Claims] 1. A nonwoven fabric structure constituted by adhering a large number of fiber masses made of short fibers, wherein said fiber masses are composed of matrix fibers and binder fibers, and said fiber masses are formed of one of the mutual contact portions. A nonwoven fabric structure characterized in that the short fibers which substantially adhere to each other at the portions and which constitute the fiber mass are arranged in a random direction within at least two surfaces of the fiber mass. 2. The nonwoven fabric structure according to claim 1, wherein the fiber mass contains fibers provided with a silicone oil agent. 3. The repulsive stress of the fiber mass at the time of 25% compression is 0.
3. The nonwoven fabric structure according to claim 1, wherein the nonwoven fabric structure has a weight of 1 to 30 × 10 ⁻² kgf / cm ² . 4. A first heat-fused state constituting a fiber mass,
The secondary heat fusion state in which the fiber masses are fused with each other structurally has a relationship of primary heat fusion part volume> second heat fusion part volume. The nonwoven fabric structure according to the above. 5. The nonwoven fabric structure according to claim 1, wherein the fiber mass is a polyester fiber. 6. A pre-spreader for short fibers by a pre-spreader,
Next, after the short fibers are deposited by automatically stacking vertically in a low deposition level portion using an air flow, the first heat fusion is performed by a heat fusion treatment to form a nonwoven fabric.
A nonwoven fabric structure manufactured by forming the nonwoven fabric into at least a fiber mass smaller than the nonwoven fabric, forming the fiber mass into a desired shape, and then performing a second fusion by a heat fusion treatment. 7. The pre-spreading of short fibers by a pre-spreading machine,
Next, after the short fibers are deposited by automatically stacking vertically in a low deposition level portion using an air flow, the first heat fusion is performed by a heat fusion treatment to form a nonwoven fabric.
A method for manufacturing a nonwoven fabric structure manufactured by forming the nonwoven fabric into a fiber mass smaller than at least the nonwoven fabric, forming the fiber mass into a desired shape, and then performing a second fusion by a heat fusion treatment.