JPH07189105A - Netlike structure having different fineness and its production - Google Patents

Abstract

PURPOSE:To obtain a netlike structure having different densities suitable for a cushioning material having excellent heat resistance, permanence and cushioning properties, hardly getting stuffy. CONSTITUTION:In a netlike structure, threads comprising a thermoplastic elastic material are bent and brought into contact with each other, most of the contact parts are fusion bonded to form a three-dimensional structure and to provide a production method for a netlike structure comprising at least plural layers integrated and composed of threads having different fineness. A thermoplastic elastic resin in a melt state is extruded downward at >=10 deg.C and <=80 deg.C higher than the melting point from an orifice of a nozzle having at least plural arrangements different in line intervals or pitches between holes in a section in the longer direction, threads are brought into contact with each other in a melt state, fusion bonded with forming a three-dimensional structure, held by a take-up device and cooled by a cooling bath to form the netlike structure by one process.

Description

Detailed Description of the Invention

[0001]

The present invention relates to a futon, furniture, bed,
TECHNICAL FIELD The present invention relates to a heterogeneous reticulated structure having excellent cushioning properties and heat resistance suitable for a vehicle cushioning material, a heat insulating material, and the like, and a method for producing the same.

[0002]

2. Description of the Related Art Currently, as cushion materials for futons, furniture, beds, trains, automobiles, etc., urethane foam, non-elastic crimp fiber stuffed cotton, and resin cotton or hard cotton to which non-elastic crimp fiber is adhered are used. Has been done.

However, although the foamed-crosslinked urethane has good durability as a cushioning material, it is apt to be stuffy due to its poor moisture permeability and heat storage and has a heat storage property, and it is difficult to recycle because it is not thermoplastic, and is burned. The damage to the incinerator is large and the cost for removing toxic gas is high.
For this reason, landfilling has become more frequent, but it is difficult to stabilize the ground, and there is a problem that landfilling sites are limited and costs increase. Further, although it has excellent processability, it also has a problem of pollution of chemicals used during manufacturing. In addition, since the fibers are not fixed in the thermoplastic polyester fiber wadding, the form may collapse during use, the fibers may move, and the crimp may cause a decrease in bulkiness and elasticity. become.

As a resin cotton in which polyester fibers are adhered with an adhesive, for example, a rubber-based adhesive is used, Japanese Patent Application Laid-Open No.
0-11352, JP-A 61-141388, JP-A 61-141391 and the like. Further, as a method using a cross-linkable urethane, JP-A-61-1377
No. 32 publication and the like. These cushion materials have inferior durability, and also have problems such as not being recyclable because they are neither thermoplastic nor single composition, and there are problems such as complexity of processability and pollution of chemicals used during manufacturing. .

Polyester hard cotton, for example, JP-A-58-3
1150, JP-A-2-154050, JP-A-3-220354, etc., but since an amorphous polymer having a brittle adhesive component of the heat-bonding fiber used is used (for example, JP-A-58). -136828, Japanese Patent Application Laid-Open No. 3-
However, there is a problem in that durability is poor such that the bonded portion is brittle and the bonded portion is easily broken during use and the form and elasticity are reduced. As an improved method, a method of entanglement treatment has been proposed in Japanese Patent Laid-Open No. 4-245965, but there is a problem that the brittleness of the bonded portion is not solved and the elasticity is largely reduced. In addition, there is complexity during processing. Further, there is a problem that the bonded portion is hard to be deformed and soft cushioning is hard to be imparted. For this reason, the polyester elastomer that is soft even at the bonded portion and recovers even if it is deformed to some extent
A heat-bonding fiber using a non-elastic polyester as a core component is disclosed in JP-A-4-240219, and a cushion material using the fiber is disclosed in WO-91 / 19032, JP-A-5-155651. It is proposed in Japanese Patent Laid-Open No. 5-163654. The adhesive component used in this fiber structure has a polyalkylene glycol content of 30 to 50 as a soft segment of polyester elastomer.
Wt%, 5% terephthalic acid as the acid component of the hard segment
It contains 0 to 80 mol% and contains isophthalic acid as another acid component composition to increase the amorphousness, and the melting point is 180
The temperature is below ℃, and the heat-bonded part is well formed with a low melt viscosity to form an ameber-shaped bonded part, but it is easy to plastically deform, and because the core component is an inelastic polyester, plastic deformation especially under heating Becomes remarkable, and there is a problem that the heat resistance and compression resistance are lowered. In addition, this fiber is
Since it is recognized to be the same as the fiber described in Japanese Patent No. 404, it cannot be said that the fiber is an improved version of the prior art.

A thermoplastic olefin network used for civil engineering work is disclosed in JP-A-47-44839. However, unlike a cushion made of fine fibers, the surface is uneven and the touch is poor, and since the material is olefin, the heat resistance durability is extremely poor and it cannot be used as a cushion material. In Japanese Patent Publication No. 3-17666, there is a method in which ejection filaments having different fineness are fused to each other to form a mold, but a net-like structure which is not suitable as a cushion material. Japanese Examined Patent Publication No. 3-55583 describes a method of thinning only a very surface with a thinning device such as a rotating body before cooling. With this method, the surface cannot be flattened and a thick thin linear layer cannot be formed. Therefore, it does not provide a comfortable cushioning material. JP-A-1-207
Japanese Patent Laid-Open No. 462 discloses a vinyl chloride floor mat, but it is not preferable as a cushioning material because it has poor compression recovery at room temperature and remarkably poor heat resistance.

[0007]

To solve the above problems,
An object of the present invention is to provide a different fineness reticulate structure suitable for a cushioning material having excellent heat resistance and cushioning properties, and a method for producing the same.

[0008]

Means for Solving the Problems The means for solving the above problems, that is, the present invention is a heterogeneous reticulated structure in which at least two reticulated structures having different fineness are integrated. Is a continuous linear body made of thermoplastic elastic resin that is bent to form a large number of loops, and the loops are brought into contact with each other in a molten state. Is a three-dimensional random loop structure that retains the shape, and the difference in the fineness of at least two reticulated structures is converted into a circular cross-sectional area. Arranged multi-fineness reticulated structure and a large number of nozzle orifices, which are combined and integrated so that the ratio (Ib / Is) of the filament to the geometrical moment of inertia (Is) is 2 or more. Has been and olfi The ratio of the cross-sectional area and maximum cross-sectional area (Sb) in the Mardan area conversion and minimal cross-sectional area (Ss) of (Sb / S
s) is from 1.5 or more nozzles having two or more different arrangements, a thermoplastic elastic resin in a molten state is discharged downward at a temperature 10 to 80 ° C. higher than the melting point, and is melted to form a uniform width. A method for producing a heterogeneous reticulated structure characterized in that a heterogeneous reticulated structure is formed in one step by sandwiching it with a take-up device and subsequently cooling it while forming a three-dimensional random loop structure that maintains its thickness. Is.

The thermoplastic elastic resin in the present invention is block-copolymerized with a soft segment, such as polyether glycol, polyester glycol, or polycarbonate glycol having a molecular weight of 300 to 5000. Polyester elastomer, polyamide elastomer,
Examples include polyurethane elastomers. By using a thermoplastic elastic resin, it becomes possible to regenerate by remelting, and thus recycling becomes easy. For example, as the polyester elastomer, a polyester ether block copolymer having a thermoplastic polyester as a hard segment and a polyalkylenediol as a soft segment, or a polyester ester having an aliphatic polyester as a soft segment A block copolymer can be illustrated. More specific examples of the polyester ether block copolymer include aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, naphthalene 2.6 dicarboxylic acid, naphthalene 2.7 dicarboxylic acid, and diphenyl 4.4'dicarboxylic acid. At least 1 of alicyclic dicarboxylic acids such as 1.4 cyclohexanedicarboxylic acid, aliphatic dicarboxylic acids such as succinic acid, adipic acid, sebacic acid dimer acid, and dicarboxylic acids selected from ester-forming derivatives thereof Seeds and 1.4 butanediol, ethylene glycol
, Trimethylene glycol, tetremethylene glycol
Aliphatic diols such as phenol, pentamethylene glycol and hexamethylene glycol, alicyclic diols such as 1.1 cyclohexane dimethanol and 1.4 cyclohexane dimethanol, or these At least one diole component selected from ester-forming derivatives and polyethylene glycol having an average molecular weight of about 300 to 5,000.
It is a ternary block copolymer composed of at least one of polyalkylene glycols such as polypropylene, polypropylene glycol, polytetramethylene glycol, and ethylene oxide-propylene oxide copolymer. The polyester ester block copolymer is a ternary block copolymer composed of at least one of the above dicarboxylic acids, diol, and polyester diol such as polylactone having an average molecular weight of about 300 to 5,000. .
Considering heat adhesion, hydrolysis resistance, stretchability, heat resistance, etc., terephthalic acid as dicarboxylic acid, or naphthalene 2.6 dicarboxylic acid, 1.4 butanediol as diole component, and poly The alkylene diol is particularly preferably a terpolymer block copolymer of polytetramethylene glycol or the terpolymer block copolymer of polylactone as the polyester diol. In a special case,
You can also use a kotatsu that has a polysiloxane-based soft segment introduced. Also, the thermoplastic elastomer resin of the present invention includes those obtained by blending the above elastomer with a non-elastomer component and those obtained by copolymerization. The melting point of the thermoplastic elastic resin of the present invention can maintain heat resistance and durability.
It is preferably 40 ° C. or higher, and more preferably 160 ° C. or higher because the heat resistance and durability are improved. If necessary, an antioxidant, a light-proofing agent or the like may be added to improve durability.

The filaments constituting the network structure of the present invention preferably have an endothermic peak below the melting point in the melting curve measured by a differential scanning calorimeter. Those having an endothermic peak below the melting point have significantly improved heat resistance and sag resistance than those having no endothermic peak. For example, a preferable polyester elastomer of the present invention contains 90 mol% or more of terephthalic acid or naphthalene 2.6 dicarboxylic acid as an acid component, and more preferably contains terephthalic acid or naphthalene 2.6 dicarboxylic acid. After transesterification of the glycol component with 95 mol% or more, particularly preferably 100 mol%, polymerization is carried out to a required degree of polymerization, and then, as a polyalkylene diol, preferably an average molecular weight of 500 or more and 5000 or less, particularly preferably Is 100
When polytetramethylene glycol of 0 or more and 3000 or less is copolymerized in an amount of 15% by weight or more and 70% by weight or less, more preferably 30% by weight or more and 60% by weight or less, the content of terephthalic acid or naphthalene 2.6 dicarboxylic acid is contained. When the amount is large, the crystallinity of the hard segment is improved, the plastic deformation is less likely to occur, and the heat resistance and fatigue resistance are improved, but after the melt heat bonding, the annealing treatment is performed at a temperature lower than the melting point by at least 10 ° C. or more. Then, the heat resistance and sagging resistance are further improved. If annealing is performed after applying compressive strain, heat resistance and sag resistance are further improved. When the melting curve of the linear structure of the network structure thus treated is measured by a differential scanning calorimeter (DSC), an endothermic peak is more clearly expressed at a temperature of room temperature or higher and melting point or lower. In the case of not annealing, no endothermic peak appears below the melting point. By analogy with this, it is considered that the annealing causes rearrangement of the hard segments and formation of pseudo-crystallization-like cross-linking points to improve the heat resistance and sag resistance. (This process is defined as pseudo crystallization process)

The net-like structure of the present invention allows the filaments made of a thermoplastic elastic resin to meander and contact each other,
The contact portions are fused to form a three-dimensional network structure. As a result, even if a large amount of deformation is applied with a very large stress, the entire fused and integrated three-dimensional network structure deforms and absorbs the stress, and when the stress is released, the rubber elasticity of the elastic resin develops. Thus, the structure can be restored to its original form. In a cushioning material containing a filament made of a known inelastic resin,
Since plastic deformation occurs and such recovery does not occur, heat resistance and durability are poor. If they are not fused, the shape cannot be maintained and the structure does not deform integrally, so that fatigue phenomenon occurs due to stress concentration and durability deteriorates, and at the same time, the shape deforms, which is not preferable. The more preferable degree of fusion in the present invention is that most of the portions where the filaments are in contact are fused, and most preferably all the contact portions are in fusion.

The filaments forming the network structure made of the thermoplastic elastic resin of the present invention are heterogeneous three-dimensional network structures in which at least a plurality of layers of filaments having different fineness are integrated. When used as a cushioning material, the function of the cushion layer is to thicken the basic fineness to make it a little harder, and a layer (abbreviated as the basic layer) responsible for vibration absorption and body retention, and a little fineness to increase the number of constituent filaments. A layer (abbreviated as surface layer) that gives a comfortable touch to the buttocks and evenly distributes the buttocks pressure as a slightly soft layer is integrated, which transforms stress and vibration as a unit. Absorption is necessary to improve sitting comfort. In addition, since the plurality of surface layers and the base layer are fused and integrated, the entire structure can be deformed by an external force, so that deterioration in sag resistance and heat resistance durability can be prevented. If the surface layer and the base layer are not melt-bonded to each other, the surface layer is likely to be selectively depressed, which is not preferable. In addition, it is more preferable that the surface layer and the basic layer are not a single layer but a multilayer, because delicate control of cushioning property and uniform dispersion of compressive stress can be easily performed. The preferred fineness difference between the filaments of the surface layer and the basic layer of the present invention is the maximum sectional secondary moment (Ib) of the basic layer / the minimum sectional secondary moment (Is) of the surface layer in terms of circular sectional area: ( Ib / Is) is 2.0 or more, and more preferably 4 or more. 2.
When it is less than 0, the above-mentioned effects are insufficiently expressed. Therefore, in order to impart other preferable functions, an optimal combination of the fineness and the density of each layer can be arbitrarily selected in consideration of the apparent density. In addition, although the average line thickness of the whole reticulate body is not particularly limited, a preferable average thickness is 0.01 to 1
It is 0 mm, more preferably 0.1 to 5 mm. In the present invention, the second moment of area when converted into a round cross section is obtained by the following equation by obtaining the diameter (d) of the round cross section. Round cross section of the second moment (I) = πd ^4/64

Although the cross-sectional shape of the filaments constituting the reticulated structure of the present invention is not particularly limited, it is possible to impart anti-compression property and bulkiness by providing a hollow cross section or a modified cross section, so that the fineness is reduced. It is particularly preferable in the present invention having a surface layer portion. The anti-compression property can be adjusted by the modulus of the material used, and the hollow ratio and the degree of irregularity can be increased for soft materials to adjust the gradient of the initial compression stress, and the hollow ratio and the degree of irregularity for materials with a slightly higher modulus can be lowered. It provides anti-compression property with good sitting comfort. As another effect of the hollow cross section and the irregular cross section, by increasing the hollow ratio and the degree of irregularity, if the same anti-compression property is given, the weight can be further reduced, and the energy saving can be achieved when it is used for the seat of an automobile or the like. If it is a futon or the like, it will be easier to handle when raising and lowering.

[0014] The apparent density of the average of the present invention the network structure is particularly, but not limited to, susceptible 0.005 g / cm ³ or more 0.20 g / cm ³ or less is preferable that the function is expressed as a cushion body, and more preferably 0 It is not less than 0.01 g / cm ^{3 and not} more than 0.10 g / cm ³ . The thickness of the mesh is
Although not particularly limited, it is preferably 3 mm or more so that the function as a cushion body is easily exhibited. The size of the random loop can be arbitrarily selected according to the intended use, but a diameter of 1 to 50 mm, particularly 2 to 15 mm is preferable. In the network structure of the present invention, at least two or more layers composed of a plurality of filaments having different fineness are integrated,
Preferable characteristics can be imparted by changing the apparent density of each layer composed of filaments having different fineness. For example, when the surface layer has a small fineness and the basic layer has a large fineness, the density of the surface layer is made slightly high to increase the number of constituents and reduce the stress received by one filament to improve the dispersion of stress. Moreover, it is possible to improve the sitting comfort by improving the cushioning property for supporting the buttocks. Since the surface of the basic layer that contacts the seat frame is a denser layer, the cushion layer is made to have uniform vibrations and repulsive stress received from the frame surface by using a fine line with a slightly finer line and a higher density. It is possible to transmit the energy and to transform the entire body integrated by the cushion layer so that the energy can be converted, so that the sitting comfort can be improved and the durability of the cushion can be improved. Further, in order to add thickness and tension to the side of the seat, the fineness can be made slightly thin to increase the density. In this way, each layer consisting of filaments having different finenesses can be arbitrarily selected with a preferable density and fineness according to its purpose. The thickness of each layer of the net-like structure is not particularly limited, but is preferably 3 mm or more so that the function as a cushion body is easily exhibited.

A line formed of a thermoplastic elastic resin having a meandering shape on the surface of the net-like structure forms a loop, and in the middle of the loop, the thickness direction of the net-like structure is taken as the base line, and 4 from the base line.
It is preferable in the present invention having a surface layer portion having a reduced fineness that the contact portion is bent by 5 ° or more, the surface is substantially flattened, and most of the contact portion is fused. As a result, the contact points of the filaments on the surface of the net-like structure are significantly increased to form bonding points, so that local external force is also received by the structure surface, and the surface structure is deformed as a whole, and the entire internal structure Also deforms to absorb the stress, and when the stress is released, the rubber elasticity of the elastic resin is developed and the structure can be restored to the original form. When the surface is not substantially flattened, when a local external force is applied to the surface, stress concentration may be selectively generated up to the linear portions of the surface and the bonding point portion. Fatigue due to stress concentration may occur and the sag resistance may decrease. When the filaments are made of thermoplastic elastic resin, the entire structure is deformed in the three-dimensional structure portion, so stress concentration is relieved. However, in the non-elastic resin, stress is concentrated at the bonding point and structural damage is caused. It will not occur and will not recover.

Next, the manufacturing method of the present invention will be described. INDUSTRIAL APPLICABILITY The reticulated structure of the present invention has a temperature of 10 ° C. or higher and 80 ° C. or lower than the melting point of the orifice of a nozzle having at least a plurality of rows having different cross-sectional areas of the orifices in the longitudinal row section using a general melt extruder In the molten state, for example, JP-A-55-
A thermoplastic elastic resin obtained by a known method such as JP-A-120626 is discharged downward, and the discharge lines in a molten state are bent and brought into contact with each other to fuse most of the contact portions to form a three-dimensional structure. While forming, sandwich with a take-up device,
Then, it is cooled in a cooling tank to form a net structure of different fineness in which a plurality of net structure layers having different fineness of discharge filaments are integrated at the same time in one step. When the cross-sectional area of the orifice is changed to give a pressure loss difference at the time of discharge,
The amount of discharge of the molten thermoplastic elastic resin extruded from the same nozzle at a constant pressure decreases with an orifice having a large pressure loss. In the present invention, a net-like structure composed of filaments of different fineness is manufactured using this principle. In the present invention, a nozzle having at least a plurality of rows having different orifice cross-sectional areas in the longitudinal section means, for example, an effective width in the longitudinal direction of 5
0 mm, the pitch between the holes in the width direction of the nozzle is constant at 10 mm,
In the case of a circular cross-section orifice shape with a constant pitch of 5 mm between rows, the orifice diameter is φ0.5 mm, 6 rows between 1 row and 6 rows.
For example, in the case of a nozzle having a width of 500 mm, for example, in a nozzle having a width of 500 mm, the method may be such that φ0.45 mm is provided between rows 9 and 9 and φ0.3 mm is provided between rows 9 and 11, and the orifice diameter in the width direction of the nozzle row is changed. , The 9th and 10th rows are φ with 10 holes on both sides in the width direction.
A method of configuring the middle 30 holes as 0.4 mm to be φ0.3 mm, changing the cross-sectional area of the orifice and changing the pitch between rows or the pitch between holes, and the pitch between both rows and holes The method of changing can also be exemplified. The orifice shape of such a nozzle may have a round cross section, but in the present invention,
The hollow or irregular cross-section of the filament makes it difficult for the three-dimensional structure formed by the ejection filament in the molten state to relax the flow. Particularly preferred. When heating for adhesion as described in Japanese Patent Application Laid-Open No. 1-2075, the three-dimensional structure is easily relaxed, a planar structure is formed, and a three-dimensional three-dimensional structure becomes difficult, which is not preferable. Next, both sides of the three-dimensional structure in a molten state are sandwiched by a take-up net, and the winding ejection lines in the molten state on both sides are bent by 45 ° or more to deform and flatten the surface, and at the same time, the ejection lines that are not bent. After forming the structure by adhering the contact points with, a rapid cooling with a cooling medium (usually, it is preferable to use water at room temperature is preferable because the cooling rate can be increased and the cost can be reduced). Obtain a three-dimensional three-dimensional network structure. Next, it is drained and dried, but if a surfactant or the like is added to the cooling medium, draining and drying may be difficult, or the thermoplastic elastic resin may swell, which is not preferable. As a preferred method of the present invention,
After cooling once, a pseudo crystallization process is performed. The pseudo-crystallization treatment temperature is at least 10 ° C. lower than the melting point (Tm), and T
It is performed at or above the α dispersion rising temperature (Tαcr) of an δ. With this treatment, the heat resistance and sag resistance are remarkably improved as compared with those having a heat absorption peak below the melting point and having no pseudo-crystallization treatment (those having no heat absorption peak). The preferred pseudo-crystallization treatment temperature of the present invention is from (Tαcr + 10 ° C) to (Tm-
20 ° C). If it is pseudo-crystallized by simple heat treatment, heat resistance and sag resistance are improved. But after cooling once, 1
It is more preferable to give a compressive deformation of 0% or more and anneal, since the heat and sag resistance is remarkably improved. When the drying step is performed after cooling once, the pseudo crystallization treatment can be performed at the same time by setting the drying temperature to the annealing temperature. In addition, a pseudo crystallization process can be performed separately. Then, it is cut into a desired length or shape and used as a cushion material. The desired loop diameter and wire diameter can be determined by the distance between the nozzle surface and the take-up conveyor installed on the cooling medium for solidifying the resin, the melt viscosity of the resin, the orifice hole diameter and the discharge amount, and the like. A pair of take-up conveyors with adjustable spacing installed on the cooling medium sandwiches and holds the melted discharge filaments to fuse the parts that are in contact with each other and continuously draw in the cooling medium to solidify it. By adjusting the distance between the conveyors when forming the body, the thickness can be adjusted while the fused net-like body is in a molten state, and a desired thickness can be obtained. The distance between the take-up conveyor and the nozzle surface is preferably within 30 cm, and if it is too long, the molten filaments are cooled and the contact portion is not fused, which is not preferable. If the conveyor speed is too high, the formation of contact points may be insufficient, or the contact point may be cooled until the fusion point is sufficiently formed, resulting in insufficient fusion of the contact portion. Further, if the speed is too slow, the melt will stay too much and the density will increase, so it is necessary to set the conveyor speed suitable for the desired apparent density.

When the reticulated structure of the present invention is used as a cushioning material, a resin used depending on the purpose and site of use,
It is necessary to select the fineness, the loop diameter, and the bulk density. For example, when used for the wadding of the surface layer, it is preferable to have a low density, a fine fineness, and a fine loop diameter in order to give a soft touch, an appropriate subsidence, and a bulge with tension. In order to lower the resonance frequency, linearly change the appropriate hardness and hysteresis at the time of compression to improve body retention, and to maintain durability, medium density, thick fineness, and slightly large ru Diameter is preferred. Further, it can be molded into a shape suitable for the purpose of use by using a molding die or the like to the extent that the three-dimensional structure is not damaged. In addition, in addition to the resin manufacturing process, it is necessary to add functions such as flame retardancy, insect repellent antibacterial, heat resistance, water and oil repellency, coloring, and aroma at any stage of processing into a molded product from the manufacturing process to the extent that performance is not degraded. It can be processed by adding chemicals.

[0018]

EXAMPLES The present invention will be described in detail below with reference to examples.

The evaluations in the examples were carried out by the following methods. Endothermic peak (melting peak) from melting point (Tm) and endothermic peak below melting point TA50, DSC50 type differential thermal analyzer manufactured by Shimadzu ) The temperature was determined. Tαcr polymer is heated to the melting point + 10 ° C and the thickness is about 300 μm.
Film was prepared and measured using a Vibron DDVII type manufactured by Orientec Co., Ltd. at a rate of 110 Hz and a temperature rising rate of 1 ° C./min. Tan δ (ratio M ″ / imaginary elastic modulus M ″ to real part M ′ of elastic modulus) The rising temperature of α dispersion corresponding to the transition temperature from the rubber elastic region to the melting region of M ′). Apparent Density The sample is cut into a size of 15 cm × 15 cm, the heights at four positions are measured, the volume is determined, and the weight of the sample is shown as a value divided by the volume. (Average value of n = 4) Fineness difference of filaments The filament portions having different fineness of the sample are cut out, embedded with resin and the cross section is cut out to obtain a section photograph. The cross-sectional area (Si) of each portion is obtained from the obtained cross-sectional photographs of the portions having different finenesses. The obtained cross-sectional area is converted into a circular cross section to obtain the diameter (Di). The cross-sectional secondary moments (Ii, Ij, ...) Are obtained from the obtained diameters, and the cross-sectional secondary moments of each part are determined.
Ment ratio. (Average of n = 5) The maximum difference in fineness (Ib / Is) is the maximum sectional secondary moment (Ib) of the basic layer / the minimum sectional secondary moment (Is) of the surface layer.
= (Ib / Is). Fusing The sample is visually judged whether it is fused or not by pulling the bonded fibers with each other by hand to judge that the fibers that cannot be separated are fused. Heat resistance and durability (residual strain at 70 ° C) Cut a sample into a size of 15 cm x 15 cm, compress it by 50%, leave it in dry heat at 70 ° C for 22 hours, cool it to remove the compression strain, and leave it for 1 day before treatment. The thickness ratio of is shown in% (n =
Average value of 3) Cyclic compression strain A sample was cut into a size of 15 cm x 15 cm, and a Shimadzu servo pulsar 50% was used at 25 ° C and 65% RH room.
The compression recovery was repeated at a cycle of 1 Hz to the thickness of 20,000 times, and the ratio of the thickness of the sample after standing 20,000 times to the thickness before treatment was%.
Indicate. (Average value of n = 3) Sitting comfort 30 ° C RH 75% Bucket seat on seat frame in room
A paneler sits on a seat formed by hanging a polyester moquette side cloth on a cushion shaped like a tongue (n = 5) (1) Feeling with the floor: "Dosun" when sitting and the degree of touching the floor Was evaluated qualitatively. Not felt; ◎, hardly felt; ○, slightly felt; △, felt; × (2) Feeling of stuffiness: Feeling stuffy when sitting for 2 hours and the buttocks and the part of the crotch that contacts the seat inside the crotch Qualitatively evaluated. Almost no feeling: ◎, slightly stuffy; ○, slightly stuffy; △, significantly stuffy; × (3) How long you can sit in the seat within 8 hours: within 1 hour; × within 2 hours; △ within 4 hours;
○ 4 hours or more; ◎ (4) A qualitative qualitative evaluation was performed on the degree of waist fatigue when the user sat in the seat for 4 hours. None; ◎, hardly tired; ○, slightly tired; △, very tired; × (5) Overall evaluation: 4 points from ◎ of the evaluations from (1) to (4), ○
3 points, △ is 2 points, × is 1 point and does not include Δ with 12 points or more; very good (⊚), that with 12 points or more; Good (○), 10 points or more is x It was evaluated as those which did not contain; those which were somewhat bad (Δ) and those which contained x; bad (x).

Examples 1 to 4 As the polyester elastomer, dimethyl terephthalate (DMT) or dimethyl naphthalate (DM) was used.
N) and 1.4 butanediol (1.4 BD) were charged with a small amount of a catalyst, and after transesterification by a conventional method, polytetramethylene glycol (PTMG) was added and polycondensation was performed while heating and depressurizing. Table 1 shows the formulation of the thermoplastic elastic resin raw material obtained by producing a terester block copolymer elastomer, then adding and mixing 1% of an antioxidant, kneading, pelletizing and vacuum drying at 50 ° C. for 48 hours. .

[0021]

[Table 1]

As a polyurethane elastomer, 4
4'diphenylmethane diisocyanate (MDI) and P
TMG and 1.4BD as a chain extender were added, and the mixture was polymerized, pelletized and vacuum dried to obtain a polyether urethane as a thermoplastic elastic resin raw material. The obtained polymer has a melting point of 152 ° C, a PTMG content of 64%, and a Tcr of -10 ° C.
Met. (Experiment No. A-4)

The obtained thermoplastic elastic resin raw material has a melting point of +3.
At a temperature of 0 ° C to 50 ° C, the pitch between rows is 5 mm in the length direction on the nozzle effective surface of width 50 cm and length 5 cm, the pitch between holes from the first row to the eighth row is 10 mm, and the orifice diameter is 1.0 mm. And, the total discharge rate was 1100 g / min from a nozzle with a hole pitch of 2.5 mm and an orifice diameter of φ0.7 mm from the 9th row to the 11th row, and cooling water was distributed 12 cm below the nozzle surface. Then, a stainless steel endless net with a width of 60 cm was arranged in parallel at intervals of 5 cm so that a pair of take-up conveyors were partly exposed on the water surface, and then picked up. It is drawn into cooling water at 25 ° C. at a speed of 1 m to be solidified and then pseudo-crystallized for 20 minutes in a hot-air dryer at 100 ° C., or it is air-dried without pseudo-crystallization and cut into a predetermined size. And average apparent density 0.043-0.044g / A network structure of cm ³ was obtained.
Table 2 shows the properties of the obtained network structure.

[0024]

[Table 2]

Comparative Examples 1-2 Polyethylene terephthalate (PE with an intrinsic viscosity of 0.63)
T) and polypropylene with a melt index of 35 (P
Except that P) was extruded at temperatures of 280 ° C and 250 ° C.
Table 2 shows the characteristics of the network structure obtained under the same conditions as in Example 1.

COMPARATIVE EXAMPLE 3 Example 2 was repeated except that a take-up conveyor net was placed 60 cm below the nozzle surface and no pseudo crystallization treatment was performed after the take-up conveyor net was taken out.
Table 2 shows some of the properties of the network structure obtained by the same method as described above. The apparent density, the residual strain at 70 ° C., and the repeated compression strain were not evaluated because the adhered state was poor and the shape retention was poor.

Comparative Example 4 Nozzle hole arrangement is 5 mm between rows and 10 mm between holes.
And, the total discharge rate was 110 at 235 ° C with the No. 2 elastomer from the nozzle with the orifice diameter of φ1.0 mm.
Table 2 shows the results of comparison of the riding comfort of the net-like structural body obtained under the same conditions as in Example 2 except that the composition was discharged at 0 g / min and the pseudo-crystallization treatment was not performed.

Embodiment 5 The orifice shape of the nozzle has the same cross sectional area as that of the round cross section and is equal to 0.
Table 2 shows the characteristics of the reticulated structure obtained under the same conditions as in Example 4 except that the Y-shaped cross section having a width of 4 mm was used.

Example 1 is a net-like structure suitable for a cushioning material that is soft and has a proper degree of sinking and has good heat resistance and durability.
It is an example of a net-like structure most suitable for a cushioning material having good heat resistance and durability. Example 4 is an example in which the pseudo-crystallization treatment using a slightly soft polyurethane-based polymer is not carried out, and it is a little soft, but the buttocks are depressed, but the sitting comfort is good. Example 5 is an example in which the softness of Example 4 is changed to a triangular cross section to improve the sitting comfort. Comparative Example 1
And Comparative Example 2 is an example using a thermoplastic non-elastic resin, which does not have an endothermic peak below the melting point even if it is subjected to pseudo-crystallization treatment,
This is an example in which heat resistance and durability are remarkably inferior, and it is hard and extremely uncomfortable to sit on and is not suitable for a cushion material. Comparative Example 3 is an example in which the fibers are not fused to each other, and the shape retention is extremely poor and is not suitable for a cushion material. This is an example in which the apparent bulk density is low, and the repulsive stress at the time of compression is low. Comparative Example 4 is an example outside the range of the present invention in which the fineness is not changed, and the sitting comfort is inferior to that of Example 2.

[0030]

EFFECTS OF THE INVENTION The reticulated structure of the present invention has a plurality of layers having different fineness of a reticulated body made of a thermoplastic elastic resin, which are fused and integrated to improve the sitting comfort, heat resistance and durability. It is bulky, has an appropriate compression repulsive force, and is a net structure suitable for a cushioning material that does not easily get damp and is easy to recycle. Therefore, it is useful for vehicle seats, boat seats, furniture cushions, and bedding products. It can be used alone or in combination with other materials. Furthermore, it can be used by various processes for stretchable nonwoven fabric applications.

Claims (4)

[Claims] 1. A heterogeneous network structure in which at least two network structures having different finenesses are integrated, wherein the network structure is formed by winding a continuous linear body made of a thermoplastic elastic resin into a large number of loops. Is a three-dimensional random loop structure having a constant width and thickness, in which most of the contact portions are fused by contacting each loop in a molten state with each other, and at least two mesh structures Ratio (Ib / Is) of the second moment of area (Ib) of the filament having a large fineness and the second moment of inertia (Is) of the filament having a small fineness when the difference in fineness of the body is converted into a circular sectional area. ) Are combined and integrated so as to be 2 or more. 2. A loop forming a reticulated structure is pressed and bent by 45 ° or more from the baseline with the thickness direction of the reticulated structure as a base line in the middle of the loop, and most of the contact portions are fused. The fine-mesh reticulated structure according to claim 1, wherein the structure is substantially flattened. 3. A large number of nozzle orifices are arranged, and the cross-sectional area of the orifices is a ratio (Sb / Ss) between the maximum cross-sectional area (Sb) and the minimum cross-sectional area (Ss) in terms of round cross-sectional area.
From a nozzle having two or more different arrangements of 1.5 or more,
A thermoplastic elastic resin in a molten state is discharged downward at a temperature higher than the melting point by 10 to 80 ° C., and is fused to form a three-dimensional random loop structure having a constant width and thickness, and is collected. A process for producing a fine-mesh reticulated structure, which comprises forming the different-fineness reticulate structure in one step by sandwiching it with a device and subsequently cooling it. 4. Once cooled, at least 10 ° C. above the melting point
The method for producing a heterogeneous network structure according to claim 3, wherein annealing is performed at a low temperature.