WO2016093334A1

WO2016093334A1 - Net-shaped object with excellent high-temperature durability

Info

Publication number: WO2016093334A1
Application number: PCT/JP2015/084745
Authority: WO
Inventors: 章文安井; 小淵　信一; 洋行涌井
Original assignee: 東洋紡株式会社
Priority date: 2014-12-12
Filing date: 2015-12-11
Publication date: 2016-06-16
Also published as: TWI684605B; JPWO2016093334A1; JP2020204143A; TW201636378A

Abstract

The purpose of the present invention is to provide a net-shaped object which, although being obtained using a polyolefin-based thermoplastic elastomer, has a given hardness, has a reduced compressive residual set even at a high temperature and a high humidity, and is suitable for use in applications such as cushions. The net-shaped object has a three-dimensional, randomly loop-bonded structure configured of continuous filaments of a polyolefin-based thermoplastic elastomer comprising an olefin block copolymer, the filaments having a fiber diameter of 0.1-3.0 mm. The net-shaped object has an apparent density of 0.005-0.20 g/cm³ and a compressive residual set measured at 70°C of 30% or less.

Description

Network structure with excellent heat resistance

The present invention is a heat-resistant and durable office chair, furniture, sofa, bed pad, mattress, vehicle seats such as trains, automobiles, motorcycles, strollers, child seats, floor mats, collision and pinching prevention members, etc. The present invention relates to a network structure suitable for a shock absorbing mat or the like.

Currently, a net-like structure is increasing as a cushioning material used for furniture, bedding such as beds, and seats for vehicles such as trains, automobiles, and motorcycles. Patent Documents 1 and 2 disclose a network structure using a polyester-based thermoplastic elastomer and a manufacturing method thereof. This is excellent in that it can solve problems such as moisture permeability and water permeability derived from polyurethane, air permeability, heat storage, VOC caused by unreacted chemicals, generation of toxic gas during combustion, and difficulty in recycling. These network structures are derived from polyester thermoplastic elastomers and are excellent in high resilience, and are widely used as high resilience cushions.

Patent Document 3 discloses a low-repulsion network structure using α-olefin. This is being widely used as a network structure excellent in low resilience and low temperature characteristics. However, in recent years, it has become difficult to simultaneously achieve high cushion performance and durability performance required by users. In particular, the lack of heat resistance and moist heat resistance due to the use of α-olefin as a raw material has been a major bottleneck.

Patent Documents 4 and 5 disclose a network structure excellent in thermal dimensional stability and a manufacturing method thereof. This is aimed at dimensional stability at 40 ° C., and an example in which a compression residual strain at 40 ° C. is 5 to 15% using a general α-olefin is disclosed.

JP 7-68061 A JP 2014-194099 A JP 2006-200118 A Japanese Patent No. 5559438 Japanese Patent No. 5559439

The present invention has been made against the background of the above-described prior art. Even in a network structure using a polyolefin-based thermoplastic elastomer, it has a predetermined hardness, and remains under compression even at high temperature and high humidity. It is an object of the present invention to provide a network structure having a small distortion and suitable for uses such as a cushion.

As a result of intensive studies to solve the above problems, the present inventors have finally completed the present invention. That is, the present invention is as follows.
(1) A network structure having a three-dimensional random loop joint structure composed of a continuous polyolefin-based thermoplastic elastomer composed of an olefin block copolymer having a fiber diameter of 0.1 to 3.0 mm. A network structure having a density of 0.005 to 0.20 g / cm ³ and a compressive residual strain at 70 ° C. of 30% or less.
(2) A network structure having a three-dimensional random loop joining structure composed of a continuous line of a polyolefin-based thermoplastic elastomer composed of an olefin block copolymer having a fiber diameter of 0.1 to 3.0 mm. A network structure having a density of 0.005 to 0.20 g / cm ³ and a compressive residual strain of 20% or less at 50 ° C. and 95% RH.
(3) A network structure having a three-dimensional random loop joining structure composed of a continuous line of a polyolefin-based thermoplastic elastomer made of an olefin block copolymer having a fiber diameter of 0.1 to 3.0 mm. A network structure having a density of 0.005 to 0.20 g / cm ³ and a compressive residual strain of 35% or less at 80 ° C. and 95% RH.
(4) The network structure according to any one of (1) to (3), wherein the olefin block copolymer is an ethylene / α-olefin block copolymer.
(5) The network structure according to (4), wherein the ethylene / α-olefin block copolymer is a block copolymer containing 50 to 95 mol% of ethylene and 5 to 50 mol% of an α-olefin having 3 or more carbon atoms. .
(6) The network structure according to (4) or (5), wherein the α-olefin is 1-octene.
(7) The network structure according to any one of (1) to (6), wherein the network structure has a thickness of 10 to 200 mm and a hardness at 25% compression of 1.5 to 30 N / φ50 mm or less.
(8) The network structure according to any one of (1) to (7), wherein the cross-sectional shape of the continuous linear body is a hollow cross section.
(9) The network structure according to any one of (1) to (8), wherein the ratio of the interfacial phase obtained by measuring the resin constituting the network structure by a pulse NMR method is 40% or less.

According to the present invention, a network structure having a small compressive residual strain can be obtained even under high temperature and high humidity heat. This net-like structure has an effect that the compressive residual strain is small even in an environment where the temperature becomes high in summer, such as a train, an automobile, a two-wheeled vehicle and the like, and in an environment where the humidity is high due to the influence of sweat generated by passengers. Furthermore, even in an environment where the temperature becomes high due to electric blankets, heaters, hot water bottles, and the like used in winter, and in an environment where the humidity is high such as in a bed, there is an effect that the compressive residual strain is small.

It is the figure which illustrated the graph of the free induction decay (FID) signal obtained by a pulse NMR method.

Hereinafter, the present invention will be described in detail.
The network structure of the present invention needs to use a continuous polyolefin-based thermoplastic elastomer composed of an olefin block copolymer. Cushioning properties can be obtained by using the characteristics of the network structure constituted by the continuous linear body and the rubber elasticity of the resin that is the material of the continuous linear body. By adopting appropriate resin, spinning conditions, and post-treatment conditions for this network structure, even if it is a network structure made of a polyolefin-based thermoplastic elastomer, the compression residual strain is small under high temperature and high humidity heat. It is possible to obtain a network structure having high durability (sag resistance). Further, by using a polyolefin-based thermoplastic elastomer, it becomes possible to regenerate by remelting, and therefore, recycling becomes easy.
The “olefin block copolymer” in the present invention is a multi-block or segment copolymer, and two or more chemically different regions or segments (also referred to as “blocks”) joined linearly. ), I.e., polymers containing chemically distinct units attached to the polymerized ethylene functional group at ends rather than in a pendant or graft fashion.

The polyolefin-based thermoplastic elastomer composed of the olefin block copolymer that is the material of the network structure of the present invention is preferably a multi-block copolymer composed of ethylene / α-olefin, and ethylene and a carbon number of 3 or more. Those obtained by copolymerizing α-olefins are preferred. Here, examples of the α-olefin having 3 or more carbon atoms include propylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-heptene, 1-octene, 1-nonene, -Decene, 1-undecene, 1-dodecene, 1-tridecene, 1-tetradecene, 1-pentadecene, 1-hexadecene, 1-heptadecene, 1-octadecene, 1-nonadecene, 1-eicosene, etc. -Butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-heptene, 1-octene, 1-nonene, 1-decene, 1-undecene, 1-dodecene, 1-tridecene, 1-tetradecene 1-pentadecene, 1-hexadecene, 1-heptadecene, 1-octadecene, 1-nonadecene, 1-eicosene. Two or more of these can also be used.

The ratio of the ethylene / α-olefin multiblock copolymer in the present invention to the ethylene and α-olefin having 3 or more carbon atoms is 50 to 95 mol% of ethylene and 5 α-olefin having 3 or more carbon atoms. It is preferably in the range of ˜50 mol%, more preferably in the range of 70 to 95 mol% of ethylene and 5 to 30 mol% of α-olefin having 3 or more carbon atoms. In general, it is known that a polymer compound is elastomeric because a hard segment and a soft segment are present in a polymer chain. In the polyolefin-based thermoplastic elastomer comprising the olefin block copolymer of the present invention, it is considered that ethylene plays a role of a hard segment, and α-olefin having 3 or more carbon atoms plays a role of a soft segment. Therefore, when the ratio of ethylene is less than 50 mol%, the number of hard segments is small, so that the rubber elasticity recovery performance is lowered. The ratio of ethylene is more preferably 70 mol% or more, further preferably 75 mol% or more, and particularly preferably 80 mol% or more. On the other hand, when the ratio of ethylene exceeds 95 mol%, since there are few soft segments, elastomeric properties are hardly exhibited and cushion performance is inferior. The ratio of ethylene is more preferably 93 mol% or less, still more preferably 90 mol% or less.

The density of the polyolefin-based thermoplastic elastomer comprising the olefin block copolymer constituting the network structure of the present invention is preferably 0.84 to 0.94 g / cm ³ , and 0.85 to 0.92 g / m. ³ is more preferable, and 0.86 to 0.90 g / m ³ is more preferable. When the density exceeds 0.94 g / cm ³ , it indicates that there are too many hard segment portions in the resin, the cushion performance is inferior, the density is high, and the network structure itself becomes heavy. When the density is less than 0.84 g / m ³ , it indicates that the hard segment for exhibiting the elastomeric property of the polyethylene-based thermoplastic elastomer made of the olefin block copolymer is insufficient, and the recovery performance by rubber elasticity. Decreases.

The melting point of the polyolefin-based thermoplastic elastomer comprising the olefin block copolymer constituting the network structure of the present invention is preferably 90 ° C or higher, more preferably 100 ° C or higher, further preferably 110 ° C or higher, 115 ° C. The above is particularly preferable, and 120 ° C. or higher is most preferable. In this invention, that melting | fusing point is less than 90 degreeC has shown that the crystal structure of the ethylene which comprises the hard segment in resin is inadequate. Although the upper limit of melting | fusing point is not specifically limited, Usually, melting | fusing point is 150 degrees C or less in the polyethylene-type thermoplastic elastomer which consists of an olefin block copolymer.

The specific heat of the polyolefin-based thermoplastic elastomer comprising the olefin block copolymer constituting the network structure of the present invention is preferably 2.26 J / g · ° C. or more, more preferably 2.28 J / g · ° C. or more. More preferably 2.30 J / g · ° C. or higher. A specific heat of 2.26 J / g · ° C. or more in a polyolefin-based thermoplastic elastomer composed of an olefin block copolymer indicates that the crystal structure of the hard segment is sufficiently present in the resin. The upper limit of the specific heat is not particularly limited, but in the case of a polyethylene thermoplastic elastomer made of an olefin block copolymer, the specific heat is usually 2.50 J / g · ° C. or less.

The melt flow rate (hereinafter referred to as “MFR”) at 190 ° C. of the polyolefin-based thermoplastic elastomer comprising the olefin block copolymer constituting the network structure of the present invention is preferably 2 to 20 g / min. 3 to 18 g / min is more preferable, and 4 to 16 g / min is even more preferable. When the MFR at 190 ° C. exceeds 20 g / min in a polyolefin-based thermoplastic elastomer composed of an olefin block copolymer, the solidification rate of the resin by cooling becomes slow, and it becomes difficult to form a network structure. On the other hand, when the MFR at 190 ° C. is less than 2 g / min, the discharge linear velocity of the resin during spinning becomes low, it becomes difficult for the continuous linear body to draw a loop, and a network structure cannot be obtained.

It is preferable to use a multi-block copolymer made of ethylene / α-olefin as the polyolefin-based thermoplastic elastomer made of the olefin block copolymer constituting the network structure of the present invention. Then, the connecting chain length of the main chain is shortened, the crystal structure is hardly formed, and the durability is lowered. One method for obtaining this multi-block copolymer is a method of copolymerizing ethylene and α-olefin using a chain shuttling reaction catalyst.

The multi-block copolymer composed of ethylene / α-olefin constituting the network structure of the present invention contains a crystalline phase, an amorphous phase, and an interfacial phase in a predetermined range. The contents of the crystalline phase, the amorphous phase and the interfacial phase can be measured using a pulsed NMR method. From the result of the relaxation time obtained by the pulse NMR method, the separation of the crystalline phase, the amorphous phase and the interfacial phase and the respective amounts can be defined.

Since the solid echo (solid echo) method of the pulse NMR method is already known, the details are omitted, but it is mainly used for measurement of samples with a short relaxation time such as glassy and crystalline polymers. This is a method that apparently eliminates the dead time. When 90 ° pulse is applied in the X-axis direction using the 90 ° x-τ-90 ° y pulse method in which two 90 ° pulses (with 90 ° phase change) are applied, dead A free induction decay (FID) signal is observed after time. When the second 90 ° pulse is applied in the y-axis direction at time τ when the FID signal does not decay, echoes appear with the magnetization directions aligned at time t = 2τ. The obtained echo can be approximated to the FID signal after the 90 ° pulse.

A method for analyzing the relationship between the physical properties, the phase separation structure, and the composition from the analysis result of the pulse NMR method is known. The free induction decay (FID) signal obtained by the pulse NMR method can be divided into three components by subtracting in order from the component having the long spin-spin relaxation time T2 by the least square method and separating the waveforms. A component having a long relaxation time is a component having a large mobility and an amorphous phase, a component having a short relaxation time is a component having a small mobility and a crystal phase, and a component having a middle relaxation time is an interface phase. The amount of each component can be determined using a calculation formula using a Gaussian function and a Lorentzian function (for example, “phase separation structure analysis of polyurethane resin by solid-state NMR (high-resolution NMR and pulsed NMR)” (DIC Technical Review No. .12, pp. 7-12, 2006)).

The measurement method of the pulse NMR method in the present invention will be described in detail as follows. First, a sample of a 1 mm diameter glass tube packed with a network structure sample cut to about 1 to 2 mm square to a height of 1 to 2 cm is placed in a magnetic field, and the macroscopic magnetization after applying a high frequency pulsed magnetic field. When the relaxation behavior is measured, a free induction decay (FID) signal is obtained as shown in FIG. 1 (horizontal axis: time (μsec), vertical axis: free induction decay signal). The initial value of the obtained FID signal is proportional to the number of protons in the measurement sample, and when the measurement sample has three components, the FID signal appears as the sum of response signals of the three components. On the other hand, since each component contained in the sample has a difference in mobility, the speed of decay of the response signal differs among the components, and the spin-spin relaxation time T2 differs. As a result, it can be divided into three components by the least square method, and the amorphous phase (L component), the interfacial phase (M component), and the crystalline phase (S component) are arranged in order from the longer spin-spin relaxation time T2. (See FIG. 1). The amorphous phase is a component having a large molecular mobility, the crystal phase is a component having a small molecular mobility, and an intermediate component is an interface phase. Regarding the pulse NMR method, solid echo method, and spin-spin relaxation time T2, JP-A-2007-238783 (particularly, paragraphs [0028] to [0033]) can be referred to.

“Spin-spin relaxation time (T2)” is used as an index of molecular mobility, and a larger value indicates higher mobility. In general, since the crystal phase has low mobility, T2 decreases, and conversely, the amorphous phase T2 increases.
The reason why the spin-spin relaxation time T2 is a measure of molecular mobility can be understood from the relationship between the correlation time τc of molecular motion and T2. It is known that τc represents an average time for a molecule in a certain motion state to undergo molecular collision, and the value of T2 is shortened in inverse proportion to the increase in τc. This indicates that T2 becomes shorter as the molecular mobility decreases.

The “component amount (phase amount)” is the ratio (mass%) of each phase, and the lower the amorphous phase T2 and the lower the amorphous phase ratio, the harder the resin. Further, the smaller the interfacial phase, the more clearly the crystal phase and the amorphous phase are separated from each other, and the elastic property is less likely to cause strain. Conversely, the greater the interfacial phase, the less the phase separation between the crystalline phase and the amorphous phase, and the delayed elastic characteristic.

In the multiblock copolymer composed of ethylene / α-olefin constituting the network structure of the present invention, the relaxation time of the crystal phase is preferably 11.4 μs or less, more preferably 11.2 μs or less, and 11.0 μm. The following is more preferable. In the present invention, the relaxation time of the crystal phase being greater than 11.4 μs indicates that the crystal phase structure is insufficient. The lower limit is not particularly limited, but is usually 1.0 μs or more for a multiblock copolymer composed of ethylene / α-olefin.

In the multi-block copolymer composed of ethylene / α-olefin constituting the network structure of the present invention, the interfacial phase fraction is preferably 40% by mass or less, more preferably 35% by mass or less, and 30% by mass. The following is more preferable.
The interface phase is the interface between the hard segment and the soft segment. The small fraction of the interface phase means that the interface between the hard segment and the soft segment is clear and the number of interfaces between the hard segment and the soft segment is small. It is shown that.
Like the multi-block copolymer composed of ethylene / α-olefin constituting the network structure of the present invention, the resin has a density within a predetermined range, that is, a resin having a crystal structure, and has an interface phase between a hard segment and a soft segment. The resin having a small ratio indicates that the crystal structure has a sufficiently large size as compared with the resin having a large interphase ratio. As a result, it is considered to have a high melting point and a large specific heat. The lower limit is not particularly limited, but in a multi-block copolymer composed of ethylene / α-olefin, it is usually 10% by mass or more.

The relaxation time of the crystal phase and the interfacial phase ratio can be changed depending on the resin used, and at the same time can be changed by heat treatment. For example, by performing an annealing process on the obtained network structure, the relaxation time of the crystal phase is shortened and the interface phase ratio is decreased.

In the network structure of the present invention, if necessary, in addition to the polyolefin-based thermoplastic elastomer, as a secondary material, polybutadiene, polyisoprene, styrene-based thermoplastic elastomers such as styrene isoprene copolymers, styrene-butadiene copolymers, and those Polymer modifiers such as hydrogenated copolymers can be blended. Furthermore, phthalate ester-based, trimellitic acid ester-based, fatty acid-based, epoxy-based, adipic acid ester-based, polyester-based plasticizers, known hindered phenol-based, sulfur-based, phosphorus-based, amine-based antioxidants, Reactions such as hindered amine, triazole, benzophenone, benzoate, nickel, salicyl and other light stabilizers, antistatic agents, peroxides and other molecular modifiers, epoxy compounds, isocyanate compounds, carbodiimide compounds, etc. Group-containing compounds, metal deactivators, organic and inorganic nucleating agents, neutralizing agents, antacids, antibacterial agents, fluorescent brighteners, fillers, flame retardants, flame retardant aids, organic and inorganic Of pigments can be added. It is also effective to increase the molecular weight of the thermoplastic resin in order to improve heat resistance and sag resistance.

The fiber diameter of the continuous linear body constituting the network structure of the present invention is 0.1 to 3.0 mm, preferably 0.2 to 2.5 mm. The fiber diameter is an important factor for the network structure to obtain a soft tactile feel and necessary hardness. If the fiber diameter is small, the hardness required for cushioning properties cannot be maintained, and conversely if the fiber diameter is too large, it becomes too hard. If the fiber diameter is less than 0.1 mm, the denseness and soft touch of the network structure are sufficient, but it is difficult to ensure the required hardness. On the other hand, when the fiber diameter exceeds 3.0 mm, it is easy to ensure the required hardness of the network structure, but the tactile sensation is hard and a stiff feeling becomes remarkable.

The apparent density of the network structure of the present invention is an important factor that determines cushioning properties, is designed according to the application, and is 0.005 to 0.20 g / cm ³ , preferably 0.01 to 0.18 g. / Cm ³ , more preferably 0.02 to 0.15 g / cm ³ . Apparent density is not maintained when the hardness required for the cushion of 0.005 g / cm ³ less than the network structure, the network structure exceeds 0.20 g / cm ³ is too hard.

The thickness of the network structure of the present invention relates to cushioning properties, preferably 10 mm to 200 mm or less, more preferably 20 to 120 mm. If the thickness is less than 10 mm, the net-like structure is too thin and a feeling of bottoming is felt. If the thickness exceeds 200 mm, it is too thick for use as a cushioning material, and comfort is impaired.

The network structure of the present invention has a 70 ° C. compressive residual strain of 30% or less, preferably 27% or less, more preferably 25% or less, still more preferably 20% or less, and particularly preferably 18%. % Or less, and most preferably 15% or less. When the 70 ° C. compressive residual strain exceeds 30%, the network structure is inferior in durability (sag resistance). The lower limit of the 70 ° C. compression residual strain is not particularly limited, but is usually 1% or more.
In the present invention, the 70 ° C. compression residual strain means that the network structure is cut into a size of 10 cm × 10 cm, the thickness is measured (thickness before treatment: a), and the compressed state is 50% of the thickness. After being left in a 70 ° C. environment for 22 hours, the compressed state is released, the mixture is cooled at room temperature for 30 minutes, and the thickness is measured again (post-treatment thickness: b), and the formula {(a)-(b)} / (a ) × 100. It can be said that the smaller this value is, the less the thickness of the network structure is reduced (sagging) even when used in an environment where the temperature is high due to a heater or a hot water bottle. That is, it is an index of thickness change (sagging) when used in a high temperature environment.

The network structure of the present invention has a 50 ° C., 95RH% compressive residual strain of 20% or less, preferably 19% or less, more preferably 18% or less, and even more preferably 15% or less. When the compression residual strain at 50 ° C. and 95 RH% exceeds 20%, the network structure is inferior in durability (sag resistance). The lower limit of 50 ° C. and 95 RH% compression residual strain is not particularly limited, but is usually 1% or more.
The 50 ° C. and 95 RH% compressive strain in the present invention means that the network structure is cut into a size of 10 cm × 10 cm, the thickness is measured (thickness before treatment: a), and the compressed state is 50% with respect to this thickness. And then left in an environment of temperature 50 ° C. and humidity 95RH% for 22 hours, then release the compressed state, cool at room temperature for 30 minutes, and measure the thickness again (thickness after treatment: b), and the formula {(a) -(B)} / (a) × 100. It can be said that the smaller this value is, the less the thickness of the net-like structure is reduced even when used in a high-temperature and high-humidity environment such as a normal car seat, vehicle seat, futon, or kotatsu. . That is, it is an indicator of thickness change (sagging) when used in a warm and humid environment.

The network structure of the present invention has a hardness retention after repeated compression of 80,000 times, preferably 68% or more, more preferably 70% or more, still more preferably 72% or more, and particularly preferably 74% or more. When the hardness retention after repeated compression 80,000 times is less than 68%, the hardness of the network structure may decrease due to long-term use, which may lead to a change in sitting comfort. The upper limit of the hardness retention after repeated compression for 80,000 times is not particularly limited, but is usually 95% or less.
The hardness retention after repeated compression of 80,000 times in the present invention is the hardness retention at 25% compression after 50% constant displacement repeated compression, and the larger this value, the more durable the network structure due to repeated deformation. It can be said that sexuality is difficult to occur.

The network structure of the present invention has a 85 ° C., 95 RH% compressive residual strain of 35% or less, preferably 31% or less, more preferably 30% or less, and even more preferably 28% or less. Preferably it is 25% or less. When the compression residual strain at 80 ° C. and 95 RH% exceeds 35%, the network structure is inferior in durability (sag resistance). The lower limit of the 80 ° C., 95 RH% compression residual strain is not particularly limited, but is usually 1% or more.
In the present invention, 80 ° C. and 95 RH% compressive residual strain means that the network structure is cut into a size of 10 cm × 10 cm, the thickness is measured (thickness before treatment: a), and the thickness is compressed by 50%. After being left in an environment of 80 ° C. and humidity of 95% for 22 hours, the compressed state is released, and cooled at room temperature for 30 minutes, and the thickness is measured again (thickness after treatment: b). ) − (B)} / (a) × 100. 80 ℃, 95RH% is considered to be the upper limit temperature / humidity environment used in car seats and vehicle seats in the summer. ). That is, it is an index of the limit of thickness change (sagging) when used in a high temperature and high humidity environment.

The 25% compression hardness of the network structure of the present invention is preferably 1.5 to 30 N / φ50 mm, more preferably 2 to 20 N / φ50 mm. If the 25% compression hardness is less than 1.5 N / φ50 mm, the network structure has a low hardness and a feeling of bottoming out. On the other hand, if it exceeds 15 N / φ50 mm, the network structure has a high hardness, and a preferable cushioning property cannot be obtained.

The 65% compression hardness of the network structure of the present invention is preferably 5 N to 30 N / φ50 mm, more preferably 6 to 25 N / φ50 mm. When the 65% compression hardness is less than 5 N / φ50 mm, the hardness of the network structure is low and a feeling of bottoming comes out. On the other hand, if it exceeds 30 N / φ50 mm, the network structure has a high hardness and a preferable cushioning property cannot be obtained.

The hysteresis loss of the network structure of the present invention is preferably 25 to 60%, more preferably 30 to 55%, still more preferably 35 to 55%. If the hysteresis loss exceeds 60%, elasticity cannot be felt. On the other hand, if the amount is less than 25%, the network structure has a too strong recovery force, so that the network structure has a hard feel.

An example of a method for producing the network structure of the present invention will be described. A network structure can be obtained by a known method described in JP-A-7-68061. For example, a polyolefin-based thermoplastic elastomer composed of an olefin block copolymer is melted using a melting temperature higher than the melting point of the polyolefin-based thermoplastic elastomer composed of an olefin block copolymer in a range of 20 to 120 ° C., and has a plurality of orifices. A polyolefin-based thermoplastic elastomer composed of an olefin block copolymer is distributed to the nozzle orifice from a multi-row nozzle. A polyolefin-based thermoplastic elastomer composed of an olefin block copolymer melted from the multi-row nozzle is discharged downward, and fused by bringing them into linear contact with each other in a molten state to form a three-dimensional structure. The three-dimensional structure is sandwiched by a take-off net installed in a take-up device, cooled in a cooling tank, then sandwiched by a nip roller, pulled out from the cooling tank, drained, dried, and smoothed on both sides or one side. A structure can be obtained. When only one side is smoothed, it is discharged on an inclined take-up net, cooled in contact with each other in a molten state to form a three-dimensional structure, and cooled while relaxing the form of only the take-up net surface, etc. Can be used.

Since the polyolefin-based thermoplastic elastomer comprising the olefin block copolymer used in the present invention has a higher melting point than the conventionally used polyolefin-based thermoplastic elastomer, the extrusion temperature during spinning can be set high. . Furthermore, since the specific heat is higher than that of the conventional polyolefin-based thermoplastic elastomer, the continuous linear body forms a loop, and has a larger amount of heat when forming a contact and contact with the adjacent linear shape. It is considered that it is possible to form a stronger contact than before.

In order to obtain the network structure of the present invention, the spinning temperature is important, and there is an appropriate range depending on the MFR of the resin. For resins with MFR = 2-5 g / min, the spinning temperature is melting point + 100-140 ° C. For MFR = 5-10 g / min, the spinning temperature is melting point + 80-100 ° C., for resins with MFR = 10-20 g / min, spinning temperature The melting point +40 to 80 ° C. is an appropriate range. When spinning at a temperature lower than the proper range, the fibers are solidified before forming the contact, and a strong contact cannot be formed. In addition, when spinning at a temperature higher than the proper range, cooling in the water tank is not sufficient, and a network structure cannot be formed.

The network structure of the present invention is superior in heat resistance and heat-and-moisture resistance compared to a network structure using a conventional polyolefin-based thermoplastic elastomer, which is thought to be because the contact points between the lines are strong. That is, even when subjected to external force such as compression in a high temperature environment of 70 ° C. or 80 ° C. and 95 RH% in a high temperature and high humidity heat environment, the contact points between the wires are strong, so that the external force is applied to the entire network structure. It will be possible to disperse. For this reason, concentration of stress can be avoided, and it is considered that heat resistance and moisture heat resistance are excellent.

In order to obtain the network structure of the present invention, the single-hole discharge amount of the polyolefin-based thermoplastic elastomer made of the olefin block copolymer discharged from the orifice of the multi-row nozzle is preferably 0.5 g / min or more, and 0.7 g / Min or more is more preferable, and 1.0 g / min or more is more preferable. If the single-hole discharge rate is less than 0.5 g / min, the continuous linear body becomes too thin to form a network structure, and at the same time, the amount of heat of the linear body itself decreases, It is difficult to form a strong contact. The upper limit of the single-hole discharge amount is not particularly limited as long as the network structure can be formed. However, when the network structure is 7.0 g / min or more, it is difficult to form the network structure because the linear body itself becomes too thick. At the same time, it becomes difficult to cool the formed network structure, and the quality may be deteriorated.

In order to obtain the network structure of the present invention, the distance between the lowermost nozzle surface and the water surface, the so-called air gap is preferably 500 mm or less, more preferably 470 mm or less, and even more preferably 450 mm or less. If the air gap is larger than 500 mm, the amount of heat of the linear body itself is reduced and a contact point with the adjacent linear shape is formed, making it difficult to form a strong contact point. The lower limit of the air gap is not particularly limited, but may be shorter as long as the network structure can be formed, but is preferably 100 mm or more. If it is smaller than 100 mm, the number of contact with the adjacent linear shape is reduced, so that it is difficult to form the network structure, and at the same time, it is difficult to cool the formed network structure, which may result in poor quality.

In order to obtain the network structure of the present invention, the take-up speed of the take-off net is preferably 10.0 m / min or less, more preferably 7.0 m / min or less, and even more preferably 5.0 m / min or less. When the take-up speed exceeds 10.0 m / min, the linear shape may not be entangled and a contact may not be formed. Although the lower limit of the take-up speed is not particularly limited, it may be slow as long as it is a range that forms a network structure, but is preferably 0.3 m / min or more. If it is slower than 0.3 m / min, cooling after the contact is formed becomes slow, and the quality may be inferior.

As one of the methods for obtaining the network structure of the present invention, heat treatment (annealing process) may be performed on the network structure obtained by cooling. The heat treatment temperature is preferably 70 ° C. or higher, more preferably 80 ° C. or higher, and further preferably 90 ° C. or higher. The heat treatment is preferably performed at a temperature lower than the melting point of the polyolefin-based thermoplastic elastomer made of the olefin block copolymer, preferably at a temperature 5 ° C. lower than the melting point, more preferably 10 ° C. lower than the melting point. The heat treatment time is preferably 1 minute or longer, more preferably 10 minutes or longer, further preferably 20 minutes or longer, particularly preferably 30 minutes or longer. The heat treatment time is preferably longer, but even if the heat treatment time is longer than a certain time, the heat treatment effect does not increase and conversely causes deterioration of the resin. Therefore, the heat treatment time is preferably within 1 hour.

When the continuous linear body constituting the network structure of the present invention is measured with a differential scanning calorimeter, the melting curve preferably has an endothermic peak from room temperature (20 ° C.) to the melting point or lower. There may be two or more endothermic peaks below the melting point, and it may appear as a shoulder depending on the proximity to the melting point and the baseline shape. Those having this endothermic peak have improved heat and humidity resistance as compared with those having no endothermic peak. Considering the measurement results of the pulsed NMR method and the phenomenon of heat and humidity resistance due to heat treatment, the amorphous phase is rearranged closer to the interface phase and the interface phase closer to the crystal phase. It can be considered that a more stable interface phase is formed.

The network structure of the present invention is a deodorizing antibacterial, deodorizing, antifouling, coloring, aroma, flame retardant in any process to be commercialized, such as a resin manufacturing process, a molding process, a post-processing process, etc. within a range not deteriorating performance Moreover, functions such as moisture absorption and desorption can be imparted.

The cross-sectional shape of the continuous linear body constituting the network structure of the present invention is not particularly limited, but a preferable anti-compression property and touch can be imparted by using a hollow cross-section, an atypical cross-section, or a combination thereof. The compression characteristics can be adjusted by the fiber diameter and the modulus of the material used. Specific examples include a method of adjusting the fiber diameter of the continuous linear body, a method of changing the cross-sectional shape of the continuous linear body to an atypical cross section or a hollow cross section, and a method of changing the hardness of the material itself used. Examples of the irregular cross section include a polygonal cross section such as a triangle, a quadrangle, and a cross shape, a cross sectional shape having protrusions on them, a star shape, a Y shape, a U shape, and a deformed cross section having a plurality of protrusions on them. . An anti-compressive property can be provided by using an irregular cross section. The anti-compression property can be adjusted according to the modulus of the material used, and the degree of initial compression stress can be adjusted by increasing the degree of deformation for soft materials, and the degree of sitting can be improved by lowering the degree of deformation for materials with slightly higher modulus. Gives good compressibility.
In particular, when using a hollow cross section or an atypical cross section, increasing the hollow ratio or the atypical degree may reduce the weight even if the compression characteristics are the same. In the case of a futon or the like, energy saving can be achieved, and the handling property when raising and lowering is improved.

As a method of making the continuous linear body constituting the network structure into a hollow cross section or an irregular cross section, for example, in the case of a hollow cross section, it is possible to use an orifice that can form a hollow orifice shape. The hollow section is easy to increase the hollowness when the polyolefin-based thermoplastic elastomer composed of the olefin block copolymer used in the network structure has a large ballistic effect, but the hollowness of the orifice is as high as possible when the ballast effect is small. Otherwise, the hollowness of the yarn will not increase, so it is necessary to select the optimum orifice shape depending on the material used. A preferable hollow ratio in the continuous linear body of the present invention is 3 to 80%, more preferably 5 to 60%, and still more preferably 10 to 50%. If the hollowness is less than 3%, the effect of hollowness is insufficient, and if it exceeds 80%, the hollow cross section tends to be deformed when subjected to stress concentration with a large force from the direction perpendicular to the cross section. Hollow crushing occurs, resulting in poor shape retention. The cross-sectional shape is not particularly limited as long as it has a hollow portion, but it is preferable to have a deformed hollow cross-section because the compression resistance is improved.

It is also a preferred embodiment in which the continuous linear bodies constituting the network structure are combined into a seascore structure and the bonding strength is improved by utilizing the melting point difference. In this case, it can be obtained by using a thermoplastic elastomer having a melting point difference of 20 ° C. or more between the thermoplastic elastomer used for the sheath component and the core component and distributing the seascore immediately before the orifice and discharging the thermoplastic elastomer. The difference in melting point between the thermoplastic elastomer used for the sheath component and the core component is more preferably 30 ° C. or more. The spinning temperature when the continuous linear body constituting the network structure is combined with the seascore structure is preferably at least 10 ° C. higher than the melting point of the low melting point component.

The network structure of the present invention includes a multilayer structure. For example, the upper surface and the lower layer can be composed of continuous linear bodies having different fiber diameters. For example, the upper layer is composed of a continuous linear body with a small fiber diameter and soft, while the lower layer is composed of a continuous linear body with a large fiber diameter to give hardness, thereby reducing both soft touch and bottoming feeling. It is also a preferred embodiment to provide a reticulated structure. Examples of the multi-layered method include a method of stacking network structures and fixing them on the side ground, a method of melting and fixing by heating, a method of bonding with an adhesive, a method of restraining with sewing or a band, and the like.

Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto. In addition, the measurement and evaluation of the characteristic value in an Example were performed as follows.

(1) Fiber diameter A sample was cut into a size of 5 cm x 5 cm, and a linear body was randomly cut out from the network structure. The fiber diameter was measured (average value of n = 10) by observing the fiber cross section in the ring cutting direction of the collected linear body with an optical microscope at an appropriate magnification.

(2) Hollow rate A sample was cut into a size of 20 cm × 20 cm, and 20 linear bodies were taken out of the sample at random. The linear body was cut into circles, placed on the cover glass in a state of standing in the fiber axis direction, the fiber cross section in the ring cutting direction was observed with an optical microscope, and the outer peripheral area (a) and the hollow area (b) of the fiber were calculated. The hollow ratio was calculated by the following formula, and the average value of 20 was obtained.
(Hollow ratio) = (b) / (a) (unit%)
At this time, when the cross-sectional shape of the linear body is a hollow cross-sectional shape, the hollow cross-sectional shape linear body is regarded, and when the cross-sectional shape is a solid cross-sectional shape linear body, an average value of only the hollow cross-sectional shape linear body is obtained. It was.

(3) Sample thickness and apparent density Four samples were cut into a size of 8 cm × 10 cm and left unloaded for 24 hours. Thereafter, a circular measuring probe with an area of 15 cm ² was used with an FD-80N type thickness gauge manufactured by Kobunshi Keiki Co., Ltd., the height of one sample was measured, and the average value was taken as the sample thickness. The sample weight was measured using an electronic balance. The apparent density was obtained by calculating the volume from the sample thickness and dividing the weight of the sample by the volume. (Average value of n = 4)

(4) Melting point The endothermic peak (melting peak) temperature was determined from an endothermic curve measured from a room temperature using a differential scanning calorimeter Q200 manufactured by TA Instruments, at a heating rate of 20 ° C./min.

(5) Specific heat Using a differential scanning calorimeter Q200 manufactured by TA Instruments, the specific heat was obtained by a method based on JIS-K7123. After holding at 10 ° C. for 10 min, the temperature was raised to 70 ° C. at 10 ° C./min, held at 70 ° C. for 10 min, the baseline was adjusted, and the difference in heat flow between the empty aluminum pan and the sample at 25 ° C. (H) From the difference in heat flow between the empty aluminum pan at 25 ° C. and the reference material (h), the weight of the sample (M), and the weight of the reference material (m), the measurement was performed using the following formula.
Specific heat (J / g · ° C.) = (H / h) × (m / M) × (specific heat of reference material)
Measurement was performed using α-alumina as a reference material.

(6) Melt flow rate (MFR) of resin (resin) at 190 ° C
The measurement was performed under the conditions of 190 ° C. and load of 2160 g by the measurement method of “ASTM D1238”.

(7) Density of Resin (Resin) Measurement was performed by a method based on “ASTM D792”.

(8) Composition analysis of resin It was carried out by ¹³ C-NMR measurement at a resonance frequency of 125 MHz. BRUKER AVANCE 500 was used as a measuring device, and heavy benzene / o-dichlorobenzene (20/80 vol%) was used as a solvent. The sample was sufficiently dissolved at 125 ° C. or higher in the aforementioned solvent, and then measured at 110 ° C. The number of integrations was 512 times or more, and the repetition time was 1 sec or more.

(9) Crystal Phase Relaxation Time Measured using a JEOL pulse NMR measurement device (JNM-MU25). Observation nucleus is 1H, measurement magnetic field strength is 0.58 Tesla, observation frequency is 25 MHz, pulse mode is Solid-Echo method, RP pulse width (Pw1) is 2.0 μs, pulse interval (Pi1) is 8.0 μs, pulse repetition The time was measured at 500 ms. The automatic induction decay signal obtained in this way is subtracted in order from the longest component by the least square method and analyzed with three components. The short relaxation component is the crystalline phase, the long component is the amorphous phase, The component was defined as the interfacial phase, and the relaxation time of the crystal phase was determined.

(10) Fraction of interfacial phase It was measured using a JEOL pulse NMR measurement device (JNM-MU25). Observation nucleus is 1H, measurement magnetic field strength is 0.58 Tesla, observation frequency is 25 MHz, pulse mode is Solid-Echo method, RP pulse width (Pw1) is 2.0 μs, pulse interval (Pi1) is 8.0 μs, pulse repetition The time was measured at 500 ms. The automatic induction decay signal obtained in this way is subtracted in order from the longest component by the least square method and analyzed with three components. The short relaxation component is the crystalline phase, the long component is the amorphous phase, The component was defined as the interfacial phase, and the fraction of the interfacial phase was determined.

(11) Hardness at 25% compression After cutting the sample into a size of 8 cm x 10 cm and leaving it in an environment of 20 ° C ± 2 ° C under no load for 24 hours, Orientec in an environment of 20 ° C ± 2 ° C Using a Tensilon RTM250 (using a 1kN load cell), a compression plate with a diameter of 50mm and a thickness of 3mm is used to start compressing the center of the sample at a speed of 10mm / min, and the thickness is measured when the load reaches 0.3N. And the hardness meter thickness. The position of the pressure plate at this time is taken as the zero point, and after compression to 75% of the hardness meter thickness at a speed of 100 mm / min, the pressure plate is returned to the zero point at a speed of 100 mm / min. Subsequently, compression was performed at a speed of 100 mm / min to 25% of the thickness of the hardness meter, and the load at that time was defined as 25% compression hardness: unit N / φ50 mm (average value of n = 3).

(12) Hardness at 65% compression The sample was cut into a size of 8 cm x 10 cm, left unloaded in an environment of 20 ° C ± 2 ° C for 24 hours, and then Orientec in an environment of 20 ° C ± 2 ° C. Using a Tensilon RTM250 (using a 1kN load cell), a compression plate with a diameter of 50mm and a thickness of 3mm is used to start compressing the center of the sample at a speed of 10mm / min, and the thickness is measured when the load reaches 0.3N. And the hardness meter thickness. The position of the pressure plate at this time is taken as the zero point, and after compression to 75% of the hardness meter thickness at a speed of 100 mm / min, the pressure plate is returned to the zero point at a speed of 100 mm / min. Subsequently, it was compressed to 65% of the thickness of the hardness meter at a speed of 100 mm / min, and the load at that time was defined as 65% hardness at the time of compression: unit N / φ50 mm (average value of n = 3).

(13) Hysteresis loss After cutting a sample into a size of 20 cm × 20 cm and leaving it in an environment of 20 ± 2 ° C. for 24 hours with no load, Tensilon RTM250 manufactured by Orientec Co., Ltd. in an environment of 20 ° C. ± 2 ° C. Using a pressure plate with a diameter of 50 mm and a thickness of 3 mm (using a 1 kN load cell), compression of the center of the sample was started at a speed of 10 mm / min, and the thickness when the load reached 0.3 N was measured. And The sample after the initial thickness measurement was 75 mm of the initial thickness at a speed of 50 mm / min using a compression plate having a diameter of 150 mm and a thickness of 20 mm in an orientex Tensilon RTM250 (using 1 kN load cell) in an environment of 20 ± 2 ° C. After compression to%, the compression plate is returned to the original position at the same speed without holding time (first stress-strain curve), and then the same operation (compression and returning) is repeated without holding time (second time) Stress strain curve). Hysteresis loss is determined according to the following equation, with the compression energy (WC) indicated by the second compression stress curve and the compression energy (WC ′) indicated by the second decompression stress curve. (Average value of n = 3)
Hysteresis loss (%) = (WC−WC ′) / WC × 100
WC = ∫PdT (Work amount when compressed from 0% to 75%)
WC ′ = ∫PdT (Work amount when decompressing from 75% to 0%)

(14) 70 ° C. compression residual strain A sample is cut into a size of 8 cm × 10 cm, and the thickness (a) before treatment is measured by the method described in (3). The sample whose thickness was measured was sandwiched between jigs capable of holding the thickness in a compressed state of 50% of thickness (a), placed in a dryer set at a temperature of 70 ° C. and a humidity of 23%, and left for 22 hours. Thereafter, the sample is taken out, cooled to remove the compressive strain, and 30 minutes later, the thickness (b) is obtained by the method described in (3). From the thickness (a) before treatment, the formula {(a)-(b)} / (A) × 100: unit% (average value of n = 3).

(15) 50 ° C., 95 RH% compression residual strain A sample is cut into a size of 8 cm × 10 cm, and the thickness (c) before treatment is measured by the method described in (3). The sample whose thickness was measured was sandwiched between jigs capable of maintaining the thickness (c) in a 50% compressed state, placed in a constant temperature and humidity chamber set to a temperature of 50 ° C. and a humidity of 95 RH%, and left for 22 hours. Thereafter, the sample is taken out, cooled to remove the compressive strain, and 30 minutes later, the thickness (d) is obtained by the method described in (3). From the thickness (c) before treatment, the formula {(c)-(d)} / (C) × 100: unit% (average value of n = 3).

(16) 85 ° C., 95 RH% compression residual strain A sample is cut into a size of 8 cm × 10 cm, and the thickness (c) before treatment is measured by the method described in (3). The sample whose thickness is measured is sandwiched between jigs capable of maintaining the thickness (e) in a 50% compressed state, placed in a constant temperature and humidity chamber set to a temperature of 80 ° C. and a humidity of 95 RH%, and left for 22 hours. Thereafter, the sample is taken out, cooled to remove the compressive strain, and after 30 minutes, the thickness (f) is obtained by the method described in (3). From the thickness (e) before the treatment, the formula {(e)-(f)} / (E) × 100: unit% (average value of n = 3).

(17) Hardness retention after repeated compression 80,000 times The sample is cut into a size of 30 cm × 30 cm, and the thickness before treatment is measured by the method described in (3). The 25% compression hardness of the sample whose thickness was measured was measured by the method described in (11), and the value was defined as the pre-treatment load (g). Thereafter, the sample whose hardness at 25% compression was measured was sandwiched between pressure plates of 30 cm × 30 cm and thickness 20 mm under a 20 ° C. ± 2 ° C. environment using a foam rubber repeated compression tester manufactured by Yasuda Seiki Seisakusho. The compression recovery is repeated 80,000 times in a cycle of 1 Hz up to 50% of the thickness. A sample after 80,000 repeated compressions is taken out from the foam rubber repeated compression tester, left to stand for 30 minutes, and then the 25% hardness at the time of compression is measured by the method described in (11). And The hardness retention after repeated compression 80,000 times is calculated from the formula (h) / (g) × 100: unit% (average value of n = 3).

[Example 1]
A nozzle having a cross-section with a triple-bridge hollow forming section with an orifice diameter of 1 mm and an inner diameter of 0.6 mm on a nozzle effective surface having a width direction of 96 mm and a thickness direction width of 31.2 mm. Using. 100% by weight of INFUSE D9530.05 (manufactured by Dow Chemicals), which is a multi-block copolymer made of ethylene / α-olefin, is used as a polyolefin-based thermoplastic elastomer made of an olefin block copolymer, and the spinning temperature is set to 240 ° C. Thus, the single hole discharge amount was discharged below the nozzle under the condition of 1.0 g / min. Cooling water is arranged at a distance of 18 cm below the nozzle surface, the temperature of the cooling water is 20 ° C., and as a take-up, a take-up device having a stainless steel endless net with a width of 300 mm is partially taken out on the water surface. Arranged. The interval between the conveyors was set to a width of 20 mm in parallel, and a three-dimensional network structure was formed while fusing the discharge line in the melted state to form a loop and fusing the contact portions. While sandwiching both sides of the three-dimensional network structure with a take-up conveyor, draw it into cooling water at a take-up speed of 0.75 m / min and solidify it, flatten both sides, cut into a predetermined size, and hot air at 105 ° C Annealing was performed for 30 minutes. Table 1 shows the characteristics of the network structure made of the polyolefin-based thermoplastic elastomer.
The resin composition of the resin constituting the network structure is performed by the above-described method by ¹³ C-NMR measurement at a resonance frequency of 125 MHz, and the molar ratio of ethylene and 1-octene as the resin composition is as follows. It was measured.
Determination of the molar ratio of 1-octene copolymerization was determined by the following method.
The peak of o-dichlorobenzene used for the solvent is observed in the vicinity of 120 to 140 ppm, and the ¹³ C peak at the 1st and 2nd positions detected on the lowest magnetic field side is set to 133.1 ppm. At that time, a peak detected in the vicinity of 10.0 to 50 ppm is a peak corresponding to 1-octene copolymer polyethylene. Among them, the peak of the tertiary carbon is 38.2 to 38.4 ppm and 35.9 to 36.1 ppm, the peak of the primary carbon is 14.0 to 14.2 ppm, and the others are secondary carbon. It corresponds to the peak. In the analysis, a tertiary carbon peak (sum of integrated values = A) and a secondary carbon peak (sum of integrated values = B) are used, and a 1-octene copolymer mol ratio ( X) of the following formula was calculated.
A × 100 / {A + (BA−6) / 2} = X (mol%)
The ethylene copolymerization mole ratio was determined by the following formula.
Y = 100-X (mol%)
Also in the following examples, the resin composition and the copolymerization mol ratio were measured in the same manner.
The obtained network structure had a hollow cross section in which the cross-sectional shape of the continuous linear body was circular, the hollowness was 30%, and the fiber diameter was 0.78 mm. The obtained network structure satisfied the requirements of the present invention, and was a network structure excellent in durability particularly under high temperature and high humidity.

[Example 2]
Example 1 was followed except that the annealing temperature was 70 ° C. The properties of the obtained network structure are shown in Table 1.
The obtained network structure had a hollow cross section in which the cross-sectional shape of the continuous linear body was circular, the hollowness was 29%, and the fiber diameter was 0.76 mm. The obtained network structure satisfied the requirements of the present invention, and was a network structure excellent in durability particularly under high temperature and high humidity.

[Example 3]
As a polyolefin-based thermoplastic elastomer composed of an olefin block copolymer to be used, 100% by weight of INFUSE D9817.15 (manufactured by Dow Chemicals), which is a multi-block copolymer composed of ethylene / α-olefin, is used, and the spinning temperature Example 1 was followed except that was 220 ° C. The properties of the obtained network structure are shown in Table 1.
The obtained network structure had a hollow cross section in which the cross-sectional shape of the continuous linear body was circular, the hollowness was 25%, and the fiber diameter was 0.68 mm. The obtained network structure satisfied the requirements of the present invention, and was a network structure excellent in durability particularly under high temperature and high humidity.

[Example 4]
Example 3 was followed except that the annealing temperature was 70 ° C. The properties of the obtained network structure are shown in Table 1.
The obtained network structure had a hollow cross section in which the cross-sectional shape of the continuous linear body was circular, the hollowness was 24%, and the fiber diameter was 0.65 mm. The obtained network structure satisfied the requirements of the present invention, and was a network structure excellent in durability particularly under high temperature and high humidity.

[Example 5]
As a polyolefin-based thermoplastic elastomer comprising an olefin block copolymer to be used, 100% by weight of INFUSE D9807.15 (manufactured by Dow Chemicals), which is a multi-block copolymer comprising ethylene / α-olefin, is used, and the spinning temperature Example 1 was followed except that the single-hole discharge amount was changed to the conditions described in Table 1. The properties of the obtained network structure are shown in Table 1.
The obtained network structure had a hollow cross section in which the cross-sectional shape of the continuous linear body was circular, the hollowness was 26%, and the fiber diameter was 0.67 mm. The obtained network structure satisfied the requirements of the present invention, and was a network structure excellent in durability particularly under high temperature and high humidity.

[Example 6]
Example 1 was followed except that the spinning temperature was 200 ° C. The properties of the obtained network structure are shown in Table 1.
The obtained network structure had a hollow cross section in which the cross-sectional shape of the continuous linear body was circular, the hollowness was 40%, and the fiber diameter was 0.95 mm. The obtained network structure was a network structure having a slightly inferior hardness retention after repeated compression 80,000 times because the contact strength was slightly weakened.

[Comparative Example 1]
Example 1 was performed except that 100% by weight of ENGAGE 8401 (manufactured by Dow Chemicals), which is an ethylene / octene random copolymer, was used as the polyolefin-based thermoplastic elastomer to be used, and the spinning temperature was 190 ° C. The properties of the obtained network structure are shown in Table 1.
The obtained network structure had a hollow section with a circular cross section of the continuous linear body, had a hollowness of 11%, and a fiber diameter of 0.5 mm. The obtained network structure was a network structure with a large compressive residual strain and poor durability under high temperature and high humidity.

[Comparative Example 2]
Comparative Example 1 was followed except that the heat treatment (annealing) conditions after cooling were changed to the conditions described in Table 1. The properties of the obtained network structure are shown in Table 1.
The obtained network structure could not maintain the network structure due to annealing conditions.

[Comparative Example 3]
In the nozzle effective surface of the width direction 1050mm, width direction width 50mm nozzle to the nozzle which made the orifice shape the outer diameter 2mm, the inner diameter 1.6mm, the orifice which made the triple bridge hollow formation cross section with the hole pitch 5mm staggered arrangement, 100% by weight of Nipolon (registered trademark) -Z7P55A (manufactured by Tosoh Corporation), an ethylene / hexene random copolymer copolymerized with a metallocene compound as a catalyst as a polyolefin-based thermoplastic elastomer, at a spinning temperature of 210 ° C. In addition, it is discharged below the nozzle at a speed of 2.0 g / min per single hole, cooling water is arranged below the nozzle surface 26 cm, and a pair of take-up conveyors with a stainless endless net having a width of 150 cm in parallel with an opening width of 40 mm. Arrange it so that it comes out partly on the water surface, and twist the discharge line in the molten state. 3-dimensional network structure while fusing the contact portion to form a to form a. The both sides of the three-dimensional network structure are sandwiched by a take-up conveyor, drawn into cooling water at a rate of 1.15 m / min and solidified by flattening both sides, and then a speed of 1.1 m / min with a nip roller, that is, a speed ratio of 4 It was taken up at 3%, cut into a predetermined size, and dried and heat treated with hot air at 70 ° C. for 30 minutes to obtain a network structure. The properties of the obtained network structure are shown in Table 1.
In the obtained network structure, the cross-sectional shape of the continuous linear body was a hollow cross section, the hollowness was 28%, and the fiber diameter was 1.2 mm. The obtained network structure was a network structure having a large compressive residual strain under high temperature and high humidity and poor durability.

[Comparative Example 4]
Example 1 was followed except that the air gap was 50 cm. Since the air gap was widened, the fiber solidified before forming the contact, and the contact could not be formed, and a network structure could not be obtained.

According to the present invention, a network structure having a small compressive residual strain can be obtained even under high temperature and high humidity heat. This net-like structure has an effect that the compressive residual strain is small even in an environment where the temperature becomes high in summer, such as a train, an automobile, a two-wheeled vehicle and the like, and in an environment where the humidity is high due to the influence of sweat generated by passengers. Furthermore, even in an environment where the temperature is high due to electric blankets, heaters, hot water bottles, etc. used in the winter, and in an environment where the humidity is high such as in a bed, it has the effect that the compressive residual strain is small, contributing greatly to the industry. It is.

Claims

A network structure having a three-dimensional random loop joining structure made of a continuous polyolefin-based thermoplastic elastomer composed of an olefin block copolymer having a fiber diameter of 0.1 to 3.0 mm, and having an apparent density of 0 A network structure having 0.005 to 0.20 g / cm 3 and a compressive residual strain at 70 ° C. of 30% or less.
A network structure having a three-dimensional random loop joining structure made of a continuous polyolefin-based thermoplastic elastomer composed of an olefin block copolymer having a fiber diameter of 0.1 to 3.0 mm, and having an apparent density of 0 A network structure of 0.005 to 0.20 g / cm 3 and a compressive residual strain at 50 ° C. and 95% RH of 20% or less.
A network structure having a three-dimensional random loop joining structure made of a continuous polyolefin-based thermoplastic elastomer composed of an olefin block copolymer having a fiber diameter of 0.1 to 3.0 mm, and having an apparent density of 0 A network structure having 0.005 to 0.20 g / cm 3 and a compressive residual strain of 35% or less at 80 ° C. and 95% RH.
The network structure according to any one of claims 1 to 3, wherein the olefin block copolymer is an ethylene / α-olefin block copolymer.
The network structure according to claim 4, wherein the ethylene / α-olefin block copolymer is a block copolymer containing 50 to 95 mol% of ethylene and 5 to 50 mol% of an α-olefin having 3 or more carbon atoms.
The network structure according to claim 4 or 5, wherein the α-olefin is 1-octene.
The network structure according to any one of claims 1 to 6, wherein the network structure has a thickness of 10 to 200 mm and a hardness at 25% compression of 1.5 to 30 N / φ50 mm or less.
The network structure according to any one of claims 1 to 7, wherein a cross-sectional shape of the continuous linear body is a hollow cross section.
The network structure according to any one of claims 1 to 8, wherein the ratio of the interface phase obtained by measuring the resin constituting the network structure by a pulse NMR method is 40% or less.