JP3314837B2 - Different density network structure and method of manufacturing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a futon, a furniture, a bed,
The present invention relates to a different-density reticulated structure having excellent cushioning properties and heat-resistant durability suitable for a cushion material for a vehicle, a heat insulating material, and the like, and a method for producing the same.

[0002]

2. Description of the Related Art At present, urethane foam, non-elastic crimped fiber-filled cotton, and resin cotton and hard cotton to which non-elastic crimped fibers are bonded are used as cushioning materials for futons, furniture, beds, trains, automobiles, and the like. Have been.

[0003] However, foamed-crosslinked urethane has good durability as a cushioning material, but is inferior in moisture permeation and water permeability and has heat storage properties, so that it is easy to humid. In addition, the damage to the incinerator is large, and the cost for removing toxic gas is high.
For this reason, landfills have been increased, but there is a problem in that it is difficult to stabilize the ground, so that landfill locations are limited and costs increase. Further, although the processability is excellent, there is a problem of pollution of chemicals used during the production. In addition, in the case of the cotton filled with thermoplastic polyester fiber, since the space between the fibers is not fixed, the shape at the time of use collapses, the fiber moves, and the crimp set causes a decrease in bulkiness and a decrease in elasticity. become.

Japanese Patent Application Laid-Open Publication No. Sho 6 (1994) discloses a resin cotton in which polyester fibers are bonded with an adhesive, for example, a rubber using an adhesive as a rubber.
Nos. 0-11352, JP-A-61-141388 and JP-A-61-141391. Further, JP-A-61-1377 discloses a method using a crosslinkable urethane.
No. 32 publication. These cushioning materials are inferior in durability, are not thermoplastic, cannot be recycled because they are not a single composition, and have problems such as complicated workability and pollution of chemicals used during production. .

[0005] Polyester hard cotton, for example, JP-A-58-3
JP-A No. 1150, JP-A-2-154050, JP-A-3-220354, etc., are disclosed in Japanese Patent Application Laid-Open No. Sho 58-58, because the adhesive component of the heat-bonding fiber used is a brittle amorphous polymer. -136828, JP-A-3-
There is a problem that the adhesive portion is brittle and the durability is poor such that the adhesive portion is easily broken during use and the form and elasticity are reduced. As an improved method, a method of performing confounding treatment has been proposed in Japanese Patent Application Laid-Open No. 4-245965, but there is a problem that the brittleness of the bonded portion is not solved and the elasticity is greatly reduced. In addition, there is also complexity in processing. Further, there is a problem that the bonded portion is hardly deformed and it is difficult to provide soft cushioning. For this reason, the adhesive is soft and the polyester elastomer recovers even if deformed to some extent.
Japanese Patent Application Laid-Open No. 4-240219 discloses a thermal bonding fiber using an inelastic polyester as a core component, and WO-91 / 19032, Japanese Patent Application Laid-Open No. 5-156561 discloses a cushioning material using the fiber. It has been proposed in, for example, JP-A-5-163654. The adhesive component used in this fiber structure contains 50 to 80 mol% of terephthalic acid in the acid component of the hard segment of the polyester elastomer, and the content of polyalkylene glycol as the soft segment is 30 to 50% by weight. %, The melting point of 180 ° C. or less as another acid component composition must be attained in JP-B-60-14.
Since it is recognized as the same as the fiber described in No. 04,
Inclusion of isophthalic acid, etc., increases the non-crystallinity and improves the formation of the heat-bonded part with low melt viscosity to form an amoeboid-shaped bonded part. Due to the elastic polyester, there is a problem that plastic deformation particularly under heating becomes remarkable, and heat resistance and compression resistance are lowered.

A thermoplastic olefin network used for civil engineering 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 an olefin, the heat resistance and durability are extremely poor and cannot be used as a cushion material. Japanese Patent Application Laid-Open No. 61-189927 describes a method of manufacturing a net-like structure having different densities in the lateral direction by changing the interval between the extruded holes. In this method, a normal and uniform discharge line having a normal melt viscosity of 5,000 poise or less is three-dimensionally looped, except for a case where the melt viscosity is extremely high and an abnormal flow is caused to cause the discharge line to bend. It is difficult to obtain a multi-layer laminated network having a uniform density by forming. JP-A-1-20
No. 7462 discloses a floor mat made of vinyl chloride, but has poor compression recovery at room temperature and extremely poor heat resistance, and is therefore not preferable as a cushioning material.

[0007]

SUMMARY OF THE INVENTION In order to solve the above problems,
It is an object of the present invention to provide a network structure having a different density and a manufacturing method suitable for a cushioning material having excellent heat resistance and cushioning property and excellent in stuffiness.

[0008]

In order to solve the above-mentioned problems, the present invention is directed to a different-density reticulated structure having at least two reticulated structures having different densities and having a surface layer and a basic layer. a body, before SL network structure forms a plurality of loops so Magarikunera a continuous filament comprising a thermoplastic elastic resin, and contacted loops each in a molten state to each other, most of the contact portion is fusion It is a three-dimensional random structure with a fixed width and thickness, attached to the surface layer and the base layer.
When the difference of the apparent density from this layer is 0.005 g / cm ³ or more ,
In addition, a network structure having different densities and a large number of nozzle orifices, wherein the surface layers are combined so as to have a lower density and are integrated, are arranged between rows in the longitudinal direction and / or between holes. From the orifice of a nozzle having at least two or more arrays having different pitches, the thermoplastic elastic resin in a molten state is discharged downward at a temperature higher than the melting point by 10 to 80 ° C., and a number of loops are formed in the molten state. contacting a loop to each other, while forming a three-dimensional random loop structure in which the shape-keeping a constant width and thickness fusing, sandwiched between take-up device, a surface by allowed to continuing cooling
A method for manufacturing a different-density network, wherein a different-density network having a lower density layer is formed in one step.

The thermoplastic elastic resin in the present invention is obtained by block copolymerizing a soft segment such as a polyether-based glycol, a polyester-based glycol, and a polycarbonate-based glycol having a molecular weight of 300 to 5,000. Polyester-based elastomer, polyamide-based elastomer,
Polyurethane-based elastomers and the like can be mentioned. By using a thermoplastic elastic resin, regeneration becomes possible by re-melting, so that recycling becomes easy. For example, as a polyester-based 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 exemplified. More specific examples of polyester ether block copolymers include aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, naphthalene 2.6 dicarboxylic acid, naphthalene 2.7 dicarboxylic acid, and diphenyl 4.4 4 'dicarboxylic acid. Alicyclic dicarboxylic acids such as 1.4 cyclohexanedicarboxylic acid, aliphatic dicarboxylic acids such as succinic acid, adipic acid, sebacic acid dimer acid, and at least one dicarboxylic acid selected from ester-forming derivatives thereof; Seeds, 1,4-butanediol, ethylene glyco-
, Trimethylene glycol, tetramethylene glycol
Alicyclic diols such as aliphatic diols such as toluene, pentamethylene glycol and hexamethylene glycol, and 1.1 cyclohexane dimethanol, and 1.4 cyclohexane dimethanol, and the like. At least one diol component selected from ester-forming derivatives and the like; and polyethylene glycol having an average molecular weight of about 300 to 5,000.
A triblock copolymer composed of at least one of polyalkylenediols such as ethylene glycol, 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 and at least one of diols and polyester diols such as polylactone having an average molecular weight of about 300 to 3,000. .
In consideration of thermal adhesion, hydrolysis resistance, stretchability, heat resistance, etc., terephthalic acid or naphthalene 2.6 dicarboxylic acid as a dicarboxylic acid, 1.4 butanediol as a diol component, poly As the alkylenediol, a triblock copolymer of polytetramethylene glycol or a terpolymer of polyester is particularly preferable. In a special case,
Those having a polysiloxane-based soft segment introduced can also be used. The thermoplastic elastomer resin of the present invention also includes those obtained by blending a non-elastomer component with the above-mentioned elastomer and copolymerizing the same. In addition, the melting point of the thermoplastic elastic resin of the present invention is 1 such that heat resistance and durability can be maintained.
A temperature of 40 ° C. or higher is preferable, and a temperature of 160 ° C. or higher is more preferable because the heat resistance and durability are improved. In addition, durability can be improved by adding an antioxidant, a light-proofing agent, or the like, if necessary.

[0010] 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 remarkably improved heat resistance and sag resistance than those having no endothermic peak. Although the reason for this is not clear, it is considered that pseudo-crystallization-like cross-linking points are formed and the heat resistance and sag resistance are improved. For example, as a preferred polyester-based elastomer of the present invention, those containing 90 mol% or more of terephthalic acid and naphthalene 2.6 dicarboxylic acid as an acid component, more preferably the content of terephthalic acid and naphthalene 2.6 dicarboxylic acid are: 95 mol% or more, particularly preferably 100 mol%
After transesterification of the glycol component with the glycol component, polymerization is effected to a required degree of polymerization. Then, as polyalkylenediol, the average molecular weight is preferably 500 or more and 5,000 or less, particularly preferably 1,000 or more and 3,000 or less. When the amount of terephthalic acid or naphthalene 2.6-dicarboxylic acid is large, hard segment crystals Although the heat resistance and the heat resistance are improved, the heat resistance is further improved by annealing at a temperature lower than the melting point by at least 10 ° C. after the fusion bonding. . Annealing after imparting compressive strain further improves heat resistance and sag resistance. When a melting curve of a line of the network structure thus treated is measured by a differential scanning calorimeter (DSC), an endothermic peak is more clearly exhibited at a temperature from room temperature to a melting point. When annealing is not performed, an endothermic peak does not appear below the melting point. By analogy with this, it is considered that the annealing may cause rearrangement of the hard segments, form pseudo-crystallization-like cross-linking points, and improve heat resistance and sag resistance.

[0011] The reticulated structure of the present invention is characterized in that a wire made of a thermoplastic elastic resin is meandered, and the wires are brought into contact with each other;
The contact portions are fused to form a three-dimensional network structure. As a result, even if a large deformation is given by a very large stress, the entire fusion-integrated three-dimensional network structure is deformed to absorb the stress, and when the stress is released, the rubber elasticity of the elastic resin is developed. 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 inferior. If not fused, the shape cannot be maintained, and the structure does not deform integrally, so that fatigue phenomena occur due to stress concentration and the durability is deteriorated, and the shape is undesirably deformed. A more preferable degree of fusion in the present invention is a state in which most of the portions in contact with the filaments are fused, and most preferably a state in which all the contact portions are fused. In addition, the average thickness of the preferable filament of the present invention is 0.
It is from 0.1 to 10 mm, more preferably from 0.1 to 5 mm.

[0012] The filament made of the thermoplastic elastic resin of the present invention has at least a plurality of layers of the network structure layer having an apparent density difference of 0.005 g / cm ³ or more of the network structure in which the filaments are fused. It is a fusion-bonded network. When used as a cushioning material, the cushion layer functions as a basic layer that absorbs vibration and maintains body shape due to its slightly hard and somewhat high density (abbreviated as the basic layer), and has a slightly low density and a little softness, so it sinks moderately Improves sitting comfort by integrating a layer (abbreviated as a surface layer) that gives a comfortable buttocks touch and distributes evenly the pressure distribution of the buttocks by integrating Is necessary. Further, by integrally deforming, it is possible to prevent a reduction in sag resistance and heat resistance. If the surface layer and the base layer are not melt-bonded, it is not preferable because the surface layer is easily removed selectively. In addition, it is more preferable that the basic layer is not a single layer but a multilayer, since fine control of cushioning can be performed. A preferable base layer has an apparent density of 0.03.
g / cm ³ or more and 0.2 g / cm ³ or less, more preferably 0.1 g / cm ³ or less.
04G / cm ³ or more 0.08 g / cm ³ or less, 0.2
If it exceeds 0 g / cm ³ , the resilience becomes strong and the sitting comfort is unfavorable. Preferred apparent density of the surface layer is 0.01 g / cm ³ or more 0.06 g / cm ³ or less, and more preferably not more than 0.02 g / cm ³ or more 0.04 g / cm ^3, is less than 0.01 g / cm ³ However, the repulsive force is lost, the sinking becomes large, and the sitting comfort is unfavorable. Unless the difference in the apparent density between the basic layer and the surface layer is at least 0.005 g / cm ³ , the above-mentioned functions cannot be provided and the sitting comfort is not improved as compared with the single-layer cushion. The difference in apparent density according to the present invention is preferably 0.01 g / cm ³ or more, more preferably 0.02 g / cm ^3.
3 or more and 0.04 g / cm ³ or less. By giving such an apparent density difference, more preferable sitting comfort can be given. The average apparent density of the different-density network structure of the present invention is not particularly limited, but is preferably 0.02 g / d.
cm ³ or more, is 0.20g / cm ³ or less. The thickness of the net-like structure is not particularly limited, but is preferably 3 mm or more in which the function as the cushion is easily exhibited. The size of the random loop can be arbitrarily selected depending on the intended use, but the diameter is 1 to 50 mm, particularly 2 to 15 m.
m is preferred.

The cross section of the filaments constituting the network structure of the present invention is not particularly limited. However, by forming a hollow cross section or a modified cross section, it is possible to impart anti-compressive properties and bulkiness, so that the density of the surface layer is reduced. Particularly preferred in the present invention having a part. The anti-compression property is adjusted by the modulus of the material used, and the gradient of the initial compressive stress can be adjusted by increasing the hollow ratio and irregularity for soft materials, and the hollow ratio and irregularity can be decreased for materials with slightly higher modulus. It provides good compression resistance 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, when the same compression resistance is imparted, the weight can be further reduced, and when used for a seat of an automobile or the like, energy saving can be achieved. In the case of a futon, the handling at the time of raising and lowering is improved.

[0014] The winding of the surface of the reticulated structure made of thermoplastic elastic resin forms a loop.
It is preferable in the present invention that the surface layer has a low-density surface layer that is bent by 5 ° or more, the surface is substantially flattened, and most of the contact portions are fused. As a result, the contact points of the filaments on the surface of the net-like structure are greatly increased to form an adhesion point, so that a local external force is received by the structural surface, and the surface structure is entirely deformed and the entire internal structure is When the stress is released by deformation, the elasticity of the elastic resin is developed and the structure can be restored to the original form. When not substantially flattened, when a local external force is applied, stress concentration may occur selectively on the surface filaments up to a portion where the three-dimensional network structure is not formed by bonding, Such an external force may cause fatigue due to stress concentration and reduce durability. When the filaments are made of a thermoplastic elastic resin, the stress concentration stops because the entire structure is deformed in the three-dimensional structure portion. However, in the case of the non-elastic resin, the stress is directly concentrated on the bonding point, and the structure is destroyed.

Next, the production method of the present invention will be described. The reticulated structure of the present invention can be obtained by using a general melt extruder, and by using a general melt extruder, the orifice of a nozzle having at least a plurality of arrangements having different pitches between rows or between holes in the longitudinal direction, from the orifice of the nozzle at a melting point of 1 or more.
At a temperature of 0 ° C. or more and 80 ° C. or less, a thermoplastic elastic resin obtained in a molten state by a known method such as Japanese Patent Application Laid-Open No. 55-120626 is discharged downward, and the discharge line in the molten state is bent. A multi-layer net-like structure having different densities of the discharge filaments, while being kneaded and in contact with each other to fuse most of the contact portions to form a three-dimensional structure, sandwiched by a take-off device, and then cooled in a cooling tank. This is a method for producing a network structure in which different density networks in which layers are simultaneously integrated are formed in one step. The arrangement in which the pitch between rows or between holes in the longitudinal section in the present invention is different means, for example, an effective width 50 in the longitudinal direction.
In the case of mm, the pitch between the holes in the row in the width direction of the nozzle is constant at 10 mm, and the pitch between the rows is changed.
mm spacing, 6mm spacing from 6 to 9 rows, 6mm spacing between 9 rows and 10 rows, 7mm spacing between rows, pitch between rows is constant at 5mm, pitch between holes in each row is 1 row From row 6 to 10 mm between holes, row 7 to 9 from hole 11.11 mm,
Examples of the method include a method in which the holes between the tenth and eleventh rows are arranged at intervals of 12.5 mm, and a method in which both pitches between the rows and between the holes are changed. The orifice shape of the nozzle having such an arrangement may have a round cross section, but in the present invention, the three-dimensional structure formed by the molten discharge line becomes difficult to relax by flowing the line into a hollow or irregular cross section, On the contrary, it is particularly preferable because the flow time at the contact point can be kept long and the adhesion point can be strengthened.
In the case of heating for bonding described in Japanese Patent Application Laid-Open No. 1-2075, it is not preferable because the three-dimensional structure is easily relaxed, and it becomes difficult to form a three-dimensional structure.
Next, the both sides of the molten three-dimensional structure are sandwiched by the take-off net, and the melted and twisted discharge lines on both sides are bent and deformed by 45 ° or more to flatten the surface and at the same time the discharge lines that are not bent. After the structure is formed by bonding the contact points with water, it is quenched continuously with a cooling medium (usually, it is preferable to use water at room temperature because the cooling rate can be increased and the cost is reduced). Obtain a three-dimensional three-dimensional network structure. Then, drying with water is performed. However, if a surfactant or the like is added to the cooling medium, draining or drying becomes difficult, and the thermoplastic elastic resin may swell, which is not preferable. As a preferred method of the present invention, a pseudo crystallization treatment is performed after cooling once. The pseudo-crystallization treatment temperature is at least 10 ° C. lower than the melting point (Tm) and is equal to or higher than the α dispersion rise temperature (Tαcr) of Tan δ. In this process,
The material has an endothermic peak below the melting point and has a remarkably improved heat resistance and sag resistance as compared with those without pseudo-crystallization treatment (without endothermic peak). The preferred pseudo crystallization treatment temperature of the present invention is (Tαcr + 10 ° C.) to (Tm−20 ° C.).
Pseudo crystallization by simple heat treatment improves heat set resistance. However, it is more preferable to perform annealing after imparting a compressive deformation of 10% or more after cooling once, since heat resistance and sag resistance are remarkably improved. Also, once cooled,
When the drying step is performed, the pseudo crystallization treatment can be performed at the same time by setting the drying temperature to the annealing temperature. Further, a pseudo crystallization treatment can be separately performed. Next, it is cut into a desired length and used as a cushion material. The desired loop diameter and wire diameter can be determined by the distance between the nozzle surface and a take-off conveyor provided on a cooling medium for solidifying the resin, the melt viscosity of the resin, the hole diameter of the orifice, and the discharge amount. A pair of take-up conveyors with adjustable intervals installed on the cooling medium sandwich and hold the discharge line in the molten state to fuse the parts that are in contact with each other, and are continuously drawn into the cooling medium to be solidified. When the body is formed, by adjusting the distance between the conveyors, the thickness can be adjusted while the fused net 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 30
When the length is too long, the molten filaments are cooled and the contact portions are not fused, which is not preferable. If the conveyor speed is too high, the contact point may be insufficiently formed, or the contact point may be cooled until the fusion point is sufficiently formed, and the fusion of the contact portion may be insufficient. On the other hand, if the speed is too slow, the melt will stay too much and the density will increase, so it is necessary to set a conveyor speed suitable for the desired apparent density.

When the net-like structure of the present invention is used for a cushion material, a resin to be used depending on the purpose of use and the site of use,
It is necessary to select fineness, loop diameter and bulk density. For example, when used for wading of the surface layer, it is preferable to use a low-density and fine fineness and a small loop diameter in order to provide a soft touch and a moderate sinking and a firm bulge. In order to lower the resonance frequency, linearly change the appropriate hardness and the hysteresis at the time of compression to improve the shape retention, and maintain the durability, medium density, thick fineness, and a slightly larger The tap diameter is preferred. In addition, it can be used by shaping it into a shape suitable for the purpose of use using a mold or the like to the extent that the three-dimensional structure is not impaired. Also, at any stage from the manufacturing process to processing into a molded body as long as the performance is not deteriorated, functionalization such as flame retardancy, insect repellent antibacterialization, heat resistance, water and oil repellency, coloring, aroma, etc. Can be processed.

[0017]

The present invention will be described in detail with reference to the following examples.

The evaluation in the examples was performed by the following method. Endothermic peak at melting point (Tm) and below melting point Using an endothermic peak (melting peak) based on an endothermic curve measured at a heating rate of 20 ° C./min using a TA50, DSC50 type differential thermal analyzer manufactured by Shimadzu Corporation. ) Temperature was determined. The Tαcr polymer is heated to the melting point + 10 ° C., and the thickness is about 300 μm.
And a Tan δ (ratio M ″ / tan δ (imaginary elastic modulus M ″ and real part M ′ of elastic modulus) measured at 110 Hz and at a heating rate of 1 ° C./min using a Vibron DDVII model manufactured by Orientec. M ′) is the rise temperature of α-dispersion corresponding to the transition point temperature from the rubber elastic region to the melting region. Apparent density A sample is cut into a size of 15 cm × 15 cm, the height is measured at four locations, the volume is determined, and the weight of the sample is indicated by a value obtained by reducing the volume by the volume. (Average value of n = 4) Apparent density difference A sample was cut into a size of 15 cm × 15 cm, and then layers having different apparent densities were cut and separated. The apparent density of each layer was measured. = 4. Welding is performed by visually judging whether or not the adhered fibers are pulled apart by hand to determine whether or not the fibers are detached. Heat resistance (70 ° C residual strain) Cut the sample into 15cm x 15cm size, compress it by 50%, leave it at 70 ° C for 22 hours in dry heat, cool it to remove the compressive strain, and leave it for one day, and before treatment Is expressed in% (n =
(Average value of 3) Repetitive compressive strain A sample was cut into a size of 15 cm × 15 cm, and 50% in a RH chamber at 25 ° C. and 65% with a SERVO pulsar manufactured by Shimadzu Corporation.
The compression recovery is repeated at a cycle of 1 Hz until the thickness of the sample reaches 20,000 times.
Indicated by (Average value of n = 3) Sit comfort 30 ° C RH75% Bucket seat on seat frame in room
A paneler sits on a seat in which a side of polyester moquette is hung on a cushion shaped like a letter (n = 5). (1) Feeling of flooring: The degree of "Donsu" when sitting and hitting the floor. Was qualitatively evaluated sensoryly. Not felt; ◎, almost felt; ○, slightly felt; △, felt; × (2) Feeling of stuffiness: After sitting for two hours, sensationally felt that the part in contact with the buttocks and the inner part of the crotch was stuffy. It was qualitatively evaluated. Almost no: ◎, slight stuffiness; ○, slight stuffiness; △, noticeable stuffiness; × (3) How long to be patient in 8 hours or less: 1 hour; × within 2 hours; △ within 4 hours;
○: 4 hours or more; ◎ (4) The degree of waist fatigue when seated in a seat for 4 hours was qualitatively evaluated sensoryly. None; ◎, hardly tired; ○, slightly tired; △, very tired; × (5) Overall evaluation: 4 points of ◎ from (1) to (4), ○
Is 3 points, Δ is 2 points, and × is 1 point, 12 points or more do not contain Δ; very good (◎), 12 points or more include Δ; good (○), 10 points or more are × Was evaluated as poor (x), poor x (x), and poor (x).

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

[0020]

[Table 1]

As a polyurethane-based elastomer, 4.
4 'diphenylmethane diisocyanate (MDI) and P
TMG and 1.4 BD as a chain extender were added, polymerized, pelletized and vacuum-dried to obtain a polyether-based urethane as a thermoplastic elastic resin raw material. The melting point of the obtained polymer is 152 ° C., the content of PTMG is 64%, and Tαcr is −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., an orifice of φ0.5 mm is arranged at an interval of 5 mm in a length direction on a nozzle effective surface having a width of 50 cm and a length of 5 cm, and a pitch between holes of 1 to 7 rows is arranged. 1
A nozzle having a pitch of 15.625 mm from 0 to 8 rows to 11 rows was discharged at a rate of 2.5 g / min for a single hole, cooling water was placed 20 cm below the nozzle surface, and stainless steel of 60 cm width was used. A pair of take-off conveyors are arranged in parallel at 5 cm intervals so that a part of the endless net is made above the surface of the water, and the conveyed parts are fused together. At a speed of 1 m / min. And then solidified in a hot air dryer at 100 ° C. for 20 minutes, or air-dried without pseudo-crystallization and cut to a predetermined size to obtain an average apparent density of 0. 0.048-0.047 g /
A net structure of cm ³ was obtained. Table 2 shows the characteristics of the obtained network structure. The apparent density difference is determined by cutting and separating the layers between the 7th row and the 8th row, and the apparent density of the high density layer is 0.054 to
0.055 g / cm ³ , apparent density of low density layer 0.037
g / cm ³ .

[0023]

[Table 2]

Comparative Examples 1-2 Polyethylene terephthalate having an intrinsic viscosity of 0.63 (PE
T) and polypropylene having a melt index of 35 (P
P) except that the extrusion temperatures were 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 Table 2 shows some of the characteristics of the net-like structure obtained in the same manner as in Example 2 except that the take-up conveyor net was arranged 60 cm below the nozzle surface and taken up. In addition, since the adhesion state is poor and the form retention is poor, the evaluation of the apparent density, the residual strain at 70 ° C., and the repeated compression strain is not performed.

Comparative Example 4 The arrangement of the nozzle holes was 8 to 11 rows, and the pitch between the holes was 10.
From the nozzle of 2mm, the elastomer of Experiment No.2 was changed to 23
At 5 ° C., a single-hole discharge amount was discharged at 2.192 g / min.
Table 2 shows the characteristics of the network structure obtained under the same conditions as in Example 2 except that the pseudo-crystallization treatment was not performed. The average apparent density was 0.0484 g / cm ³ , and the difference in apparent density was 7 between layers.
By cutting and separating between rows and 8, the apparent density of the high density layer is 0.050 g / cm ³ , and the apparent density of the low density layer is 0.048
g / cm ³ . Table 2 shows the results of comparison of ride comfort.

Example 5 Table 2 shows the characteristics of the reticulated structure obtained under the same conditions as in Example 4 except that the orifice shape of the nozzle was a shape having bridges at three places where a hollow cross section could be formed. The average apparent density was 0.0484 g / cm ³ , and the difference in apparent density was that the layers were cut and separated between row 7 and row 8 to obtain an apparent density of the high density layer of 0.055 g / cm ³ and a low density layer of the low density layer. Apparent density 0.0
It was 38 g / cm ³ .

Example 1 is a net-like structure suitable for a cushioning material which is soft and moderately sinks and has good heat resistance and durability. Examples 2 and 3 are slightly hard and have a good shape retention.
It is an example of a net-like structure suitable for a cushion material having good heat resistance and durability. In addition, Example 4 is an example in which pseudo-crystallization treatment using a slightly soft polyurethane polymer is not performed. Since the softness is slightly soft, there is a sink in the buttocks, but the sitting comfort is good. The fifth embodiment is an example in which the softness of the fourth embodiment is changed to a hollow section to improve the sitting comfort. Comparative Examples 1 and 2 are examples using a thermoplastic inelastic resin, and have no endothermic peak below the melting point even after pseudo-crystallization treatment, and have extremely poor heat resistance and durability, and are hard and comfortable to sit on. This is an example that is extremely bad and is not suitable for a cushion material. Comparative Example 3
Is an example in which fibers are not fused to each other, and has extremely poor shape retention and is not suitable for a cushion material. This is an example in which the apparent bulk density is low, and is not suitable for a cushioning material having a remarkable floor feeling due to a low repulsive stress at the time of compression and having poor sitting comfort. Comparative Example 4 is an example in which the apparent bulk density difference is out of the range of the present invention, and the sitting comfort is inferior to Example 2.

[0029]

The reticulated structure of the present invention has a plurality of layers having different apparent densities of a reticulated reticulated body made of a thermoplastic elastic resin, which are fused and integrated to further improve the sitting comfort and the heat resistance and durability. It is a bulky, moderately compressive rebound, easy-to-recycle mesh structure suitable for cushion material that is resistant to stuffiness, so it can be used for vehicle seats, marine seats, furniture cushions,
Useful for bedding products. It can be used alone or in combination with other materials. Furthermore, it can be used in various applications for elastic nonwoven fabric applications.

Continuation of the front page (56) References JP-A-2-92214 (JP, A) JP-A-5-138789 (JP, A) JP-A-5-272043 (JP, A) JP-A-58-109670 (JP) JP-A-1-207462 (JP, A) JP-A-5-311561 (JP, A) JP-A-58-81664 (JP, A) JP-A-5-214651 (JP, A) JP-A-5-329281 (JP, A) JP-A-5-337258 (JP, A) JP-A-5-261184 (JP, A) JP-A-2-18371 (JP, A) U) Actually open Hei 2-18300 (JP, U) (58) Field surveyed (Int. Cl. ⁷ , DB name) D04H 1/00-18/00 B68G 1/00-15/00 B32B 1/00- 35/00

Claims (4)

(57) [Claims] 1. A least two different network structure density are integrated, a different density reticulated structure having a surface layer and a base layer, a continuous line before SL network structure made of a thermoplastic elastic resin Forming a large number of loops by twisting the strip body, bringing each loop into contact with each other in a molten state,
Most of the contact portions are fused, a three-dimensional random structure having a fixed width and thickness, the surface layer and the base layer
And the difference in apparent density from the above is 0.005 g / cm ³ or more , and
A different-density reticulated structure characterized by being integrated by combining surface layers with a lower density . 2. A loop forming a network structure is pushed and bent at least 45 ° from the base line in the middle of the loop with the thickness direction of the network structure as a base line, and most of the contact portions are fused. 2. The network of claim 1, wherein the structure is substantially flat. 3. A nozzle having a plurality of nozzle orifices arranged therein and having at least two or more arrays having different pitches between rows and / or holes in a longitudinal direction.
The thermoplastic elastic resin in a molten state is discharged downward at a temperature higher than the melting point by 10 to 80 ° C., and a number of loops are formed in a molten state. Forming a three-dimensional random loop structure with the same thickness as that of the surface , sandwiching it with a take-off device, and continuing to cool it to form a different-density network structure in which the surface layer has a lower density in one process. A method for producing a network structure having a different density. 4. Once cooled, at least 10
4. The method for producing a network of different densities according to claim 3, wherein annealing is performed at a temperature lower than or equal to C.