TWI720225B - Mesh structure - Google Patents

Abstract

The present invention provides a net-like structure having a three-dimensional random loop joint structure composed of continuous linear bodies, and the continuous linear bodies are made of polystyrene-based thermoplastic elastomer as 45% by mass The fiber composed of the above-mentioned main component resin, the polystyrene-based thermoplastic elastomer is a mixture of the first triblock copolymer and the second triblock copolymer; the above first triblock copolymer is polymerized by styrene The second triblock copolymer is composed of styrene polymer block-butadiene polymer block-styrene polymer block It is composed of at least any one of the styrene polymer block and the copolymer block of butadiene and isoprene-styrene polymer block.

Description

Mesh structure

The present invention relates to a net-like structure with low resilience, excellent durability and no bottom-touch feeling. The net-like structure can be suitably used for bedding such as office chairs, furniture, sofas, and beds. Shock-absorbing materials used in vehicle seats such as trams, cars, two-wheeled vehicles, baby carriages, child seats, etc., sleeping bags, cushions, and other shock-absorbing materials that have many transport opportunities, floor mats, and collisions , Anti-pinch members and other shock-absorbing pads, etc.

Currently, mesh structures are increasing as shock-absorbing materials used in furniture, beds, and other bedding, as well as seats for vehicles such as trams, automobiles, and motorcycles.

For example, Japanese Patent Application Laid-Open No. 2013-076201 (Patent Document 1) discloses a net-like structure composed of a three-dimensional random loop joint structure. The three-dimensional random loop joint structure system uses The continuous linear body of 100 dtex to 100,000 dtex is bent to form random loops, so that each loop is in contact with each other in a molten state, and most of the contact parts are welded, and the continuous linear system is composed of 10 mass It is composed of a resin composition of a polyester-based thermoplastic elastomer of 90 to 90 parts by mass and a polystyrene-based thermoplastic elastomer of 90 to 10 parts by mass.

In addition, Japanese Patent Application Laid-Open No. 2003-012905 (Patent Document 2) discloses a shock absorbing body composed of an assembly of a plurality of strands, and the assembly system of the plurality of strands is made of a thermoplastic elastomer. A plurality of strands of the composition are randomly bent and the contact parts of each other are welded, and the thermoplastic elastic system is composed of the following composition, the composition is 100 parts by weight of thermoplastic polyester elastomer, 10 parts by weight Parts to 900 parts by weight of olefin-based and/or styrene-based thermoplastic elastomers and 0 parts by weight to 100 parts by weight of the components of a modified polymer having epoxy groups or derivatives thereof in the molecule, and The Shore A hardness is 50 or more and 90 or less.

[Prior Technical Literature] [Patent Literature]

Patent Document 1: JP 2013-076201 A.

Patent Document 2: Japanese Patent Laid-Open No. 2003-012905.

Although the mesh structure disclosed in JP 2013-076201 A (Patent Document 1) can achieve low resilience, it has the problem of low hardness and bottoming feeling. In addition, there is compression due to the large amount of hard components. The problem of increased residual stress and poor durability.

The damping body disclosed in Japanese Patent Laid-Open No. 2003-012905 (Patent Document 2) has a small residual compressive strain, but has a high resilience force, so there is a problem that low resilience cannot be obtained.

Therefore, the object of the present invention is to solve the above-mentioned problems and provide a mesh structure having low resilience, excellent durability, and no bottoming feeling.

[1] A network structure having a three-dimensional random loop joint structure composed of continuous linear bodies, and the continuous linear bodies are composed of polystyrene-based thermoplastic elastomer as a main component of 45% by mass or more The polystyrene-based thermoplastic elastomer is a mixture of the first triblock copolymer and the second triblock copolymer; the above-mentioned first triblock copolymer is composed of styrene polymer blocks- Is composed of isoprene polymer block-styrene polymer block; the above-mentioned second triblock copolymer is composed of styrene polymer block-butadiene polymer block-styrene polymer block and The styrene polymer block is composed of at least any one of the copolymer block of butadiene and isoprene and the styrene polymer block.

[2] The network structure as described in [1] above, wherein the content of styrene is 5 mass% or more and 45 mass% or less.

[3] The network structure as described in the above [1] or [2, wherein the mass ratio of the second triblock copolymer to the first triblock copolymer is 0.25 or more and 2.20 or less.

[4] The mesh structure as described in any one of [1] to [3] above, wherein the compressive residual strain at 40° C. is 40% or less.

[5] The mesh structure as described in any one of [1] to [4] above, wherein the hysteresis loss due to compression is 35% or more.

[6] The mesh structure as described in any one of [1] to [5] above, wherein the compression deflection coefficient is 10 or less.

[7] The mesh structure as described in any one of [1] to [6] above, wherein the fiber diameter of the continuous linear body is 0.1 mm or more and 3.0 mm or less, and the thickness of the mesh structure is 5 mm or more and 300 mm the following.

[8] The network structure as described in any one of [1] to [7] above, wherein the tanδ of the resin at 25° C. measured with a dynamic viscoelasticity measuring device is 0.3 or more.

[9] The network structure according to any one of [1] to [8] above, wherein the Shore A hardness of the resin is 40 or more.

[10] The mesh structure as described in any one of [1] to [9] above, wherein the use of the mesh structure is a shock-absorbing material, an impact-absorbing material, or a cushioning material.

[11] The mesh structure as described in any one of [1] to [9] above, which is a shock-absorbing material, an impact-absorbing material, or a cushioning material.

According to the present invention, it is possible to provide a mesh structure having low resilience, excellent durability, and no bottoming feeling.

Figure 1 is a schematic diagram of the compression and decompression tests in the measurement of the hysteresis loss of the mesh structure.

The network structure system of a certain embodiment of the present invention has a three-dimensional random loop joint structure composed of continuous linear bodies, and the continuous linear bodies are made of polystyrene-based thermoplastic elastomer as 45% by mass or more. A fiber composed of a resin as the main component. The polystyrene-based thermoplastic elastomer is a mixture of the first triblock copolymer and the second triblock copolymer; the above-mentioned first triblock copolymer is embedded with a styrene polymer. Segment-isoprene polymer block-styrene polymer block; the second triblock copolymer is composed of styrene polymer block-butadiene polymer block-styrene polymer block Segment and at least any one of styrene polymer block-butadiene and isoprene copolymer block-styrene polymer block. Since the mesh structure of this embodiment forms a three-dimensional random loop joint structure, the continuous linear system is composed of a resin containing polystyrene-based thermoplastic elastomer as a main component of 45% by mass or more, and polystyrene-based thermoplastic The elastomer is a mixture of the first triblock copolymer and the second triblock copolymer, so it has low resilience, excellent durability, and no bottoming feeling. The so-called "bottom touch" here refers to, for example, when a load is applied from the upper surface of the mesh structure with a hand, the mesh structure is compressed, and the hand directly touches the floor surface which is in direct contact with the lower surface of the mesh structure. Feel like face contact. The bottoming feeling is felt when the rigidity and resilience of the mesh structure are insufficient.

The mesh structure of this embodiment has a three-dimensional random loop joint structure composed of continuous linear bodies. In detail, the mesh structure of the present embodiment has a three-dimensional random loop joining structure that is joined by bending a continuous linear body to form random loops, and the respective loops are brought into contact with each other in a molten state . That is, "continuous linear body" refers to an object formed by connecting straight lines, curved lines, broken lines, and other linear shapes. In addition, the so-called "three-dimensional random loop joint structure" refers to bending one or a plurality of continuous linear bodies to form arbitrary shapes such as loops with random sizes or directions, and forming plural linear bodies of arbitrary shapes to fuse each other A three-dimensional structure formed by state contact, whereby at least a part of it is joined.

{Continuous linear body}

The continuous linear body is a fiber composed of a resin containing a polystyrene-based thermoplastic elastomer as a main component of 45% by mass or more, preferably 55% by mass or more, and more preferably 65% by mass or more. The main component here refers to the component that contains the largest amount in the resin. The presence of the polystyrene-based thermoplastic elastomer contained in the continuous linear body is confirmed by the polystyrene peak of the infrared absorption spectrum, and the content of the polystyrene-based thermoplastic elastomer is determined by GPC (Gel Permeation Chromatography; Gel permeation chromatography). In addition, the upper limit of the content of the polystyrene-based thermoplastic elastomer contained in the continuous linear body may be 75% by mass or less.

In the continuous linear body of the mesh structure of this embodiment, from the viewpoint of ensuring the excellent durability and low resilience of the mesh structure, the content of styrene is preferably 5% by mass or more and 45% by mass Below, more preferably 5% by mass or more and 40% by mass or less, still more preferably 7% by mass or more and 40% by mass or less, still more preferably 7% by mass or more and 37% by mass or less, and particularly more preferably 10% by mass or more and 35% by mass the following. The content of styrene ^{was measured by 1} H-NMR (Nuclear Magnetic Resonance; nuclear magnetic resonance). The “content rate of styrene” here refers to the content rate (mass %) of the repeating unit derived from the styrene monomer in the polystyrene-based thermoplastic elastomer based on the mass of the network structure.

{Polystyrene-based thermoplastic elastomer}

The polystyrene-based thermoplastic elastomer is a mixture of the first triblock copolymer and the second triblock copolymer; the above-mentioned first triblock copolymer is composed of a styrene polymer block-isoprene polymer. Segment-styrene polymer block; the above-mentioned second triblock copolymer is composed of styrene polymer block-butadiene polymer block-styrene polymer block and styrene polymer block- It is composed of at least any one of the copolymer block of butadiene and isoprene-styrene polymer block. Since the polystyrene-based thermoplastic elastomer of the thermoplastic elastomer of this embodiment is a mixture of the first triblock copolymer and the second triblock copolymer, it has the following characteristics: low resilience, excellent durability, and No sense of bottoming.

(The first triblock copolymer)

The first triblock copolymer is a triblock copolymer composed of three blocks of styrene polymer block-isoprene polymer block-styrene polymer block. The first triblock copolymer contains isoprene polymer blocks to form a network structure with low resilience. The existence of the first triblock copolymer and the content rate of the first triblock copolymer ^{are measured by 1} H-NMR.

The manufacturing method of the 1st triblock copolymer is not specifically limited, It can manufacture by a well-known method. For example, it can be produced by any of anionic polymerization or cationic polymerization plasma polymerization method, single site polymerization method, and radical polymerization method. In the case of using the anionic polymerization method, for example, the following methods (i) to (iii) can be cited.

(i) A method in which an alkyl lithium compound (for example, n-butyl lithium) is used as a polymerization initiator to gradually polymerize an aromatic vinyl compound (for example, styrene monomer), isoprene, and an aromatic compound.

(ii) A method in which an alkyl lithium compound is used as a polymerization initiator, an aromatic vinyl compound and isoprene are gradually polymerized, and then a coupling agent is added for coupling.

(iii) A method in which a dilithium compound is used as a polymerization initiator to gradually polymerize isoprene and then an aromatic vinyl compound.

Here, the above-mentioned anionic polymerization is preferably carried out in the presence of a solvent. The solvent is not particularly limited as long as it is inactive to the polymerization initiator and does not adversely affect the polymerization reaction. For example, saturated aliphatic hydrocarbons or aromatic hydrocarbons, such as hexane, cyclohexane, heptane, octane, decane, toluene, benzene, xylene, etc. are mentioned.

In addition, in the case of using any one of the methods (i) to (iii) above, the polymerization reaction can be carried out at a temperature of usually 0°C to 80°C, preferably 10°C to 70°C, more preferably 10°C It is carried out at a temperature of 60°C for 0.5 hour to 50 hours, preferably 1 hour to 30 hours.

(2nd triblock copolymer)

The second triblock copolymer is a triblock copolymer composed of at least any one of the following triblock copolymers: styrene polymer block-butadiene polymer block-styrene polymer Block a triblock copolymer composed of the three blocks, and a copolymer block of styrene polymer block-butadiene and isoprene-styrene polymer block the three blocks The constituted triblock copolymer. When the second triblock copolymer contains a butadiene polymer block or a copolymer block of butadiene and isoprene, a network structure with excellent durability is formed. The existence of the second triblock copolymer and the content rate of the second triblock copolymer ^{are measured by 1} H-NMR. The copolymer block of butadiene and isoprene in the tri-block copolymer composed of styrene polymer block-butadiene and isoprene copolymer block-styrene polymer block In the stage, it is preferable to contain at least 50% by mass or more of the repeating unit derived from the butadiene monomer. Furthermore, in the triblock copolymer composed of styrene polymer block-butadiene and isoprene copolymer block-styrene polymer block, the difference between butadiene and isoprene In the copolymer block, butadiene and isoprene may be separately copolymerized as blocks, or may be copolymerized randomly with each other.

Regarding the production method of the second triblock copolymer, it is also possible to use the same method as the first triblock copolymer and change isoprene to butadiene (for example, 1,3-butadiene monomer ) Or butadiene and isoprene.

From the viewpoint of ensuring excellent durability and low resilience of the network structure, the mass ratio of the second triblock copolymer to the first triblock copolymer is preferably 0.25 or more and 2.20 or less, more preferably 0.30 Above 2.10 or less, more preferably 0.35 or more and 2.00 or less.

{Other ingredients}

From the viewpoint of eliminating bottoming feeling (improving rigidity), the resin forming the continuous linear body of the mesh structure of this embodiment may contain polyolefin (for example, polypropylene), in addition to polystyrene-based thermoplastic elastomer, Paraffin-based process oil, hydrogenated terpene resin, etc.

From the viewpoint of ensuring excellent durability of the mesh structure of this embodiment, the compressive residual strain at 40°C of the mesh structure is preferably 40% or less, more preferably 35% or less, and still more preferably 30% or less . The lower limit of the compressive residual strain at 40°C is not specifically defined, and it is 1% or more in the mesh structure of the present embodiment. _{Here, the compressive residual strain at 40°C is based on the thickness t b} before compression and the thickness t _a after compression when the sample is 50% compressed in an atmosphere temperature of 40°C for 22 hours, by (t _b -t _a )/t _b ×100. The thickness of the sample before compression and the thickness after compression can be measured, for example, by the method described in the column of "(4) 40°C Compression Residual Strain" in the examples described later.

From the viewpoint of ensuring low resilience of the mesh structure of the present embodiment, the hysteresis loss due to compression is preferably 35% or more, more preferably 38% or more, and still more preferably 40% or more. Furthermore, from the viewpoint of having a sufficient shape recovery speed as a mesh structure, the hysteresis loss due to compression is preferably 98% or less, and more preferably 95% or less. Here, the hysteresis loss caused by compression is based on the compression energy WC represented by the stress curve during compression and the compression energy WC' represented by the stress curve during decompression, by (WC-WC')/WC×100 And figure it out. The compression energy WC and the compression energy WC' can be obtained, for example, by the method described in the column of "(5) Hysteresis loss" in the embodiment described later.

From the viewpoint that the mesh structure of the present embodiment does not feel the bottom touch, the compression deflection coefficient is preferably 10 or less, more preferably 9.9 or less, and still more preferably 9.8 or less. The lower limit of the compressive deflection coefficient is not specifically defined, but it is 1.0 or more in the mesh structure of the present embodiment. Here, the flexibility factor based compression hardness by ₆₅ H H ₆₅ / H ₂₅ 25 when calculated from the _25% compression and 65% compression hardness H. The compression deflection coefficient can be obtained by the method described in the column of "(6) Compression deflection coefficient" in the embodiment described later.

In the mesh structure of this embodiment, from the viewpoint of obtaining the hardness necessary for the mesh structure and obtaining shock absorption properties, the fiber diameter of the continuous linear body is preferably 0.1 mm or more and 3.0 mm or less, more preferably 0.2 mm or more and 2.5 mm or less, more preferably 0.3 mm or more and 2.0 mm or less. The fiber diameter of the continuous linear body can be obtained, for example, by the method described in the column of "(7) Fiber diameter" in the examples described later. In addition, from the viewpoint of eliminating bottoming feeling and from the viewpoint of the upper limit of the manufacturing device, the thickness of the mesh structure is preferably 5 mm or more and 300 mm or less, more preferably 7 mm or more and 280 mm or less, and still more preferably 10 mm or more and 250 mm or less. The thickness of the mesh structure can be obtained, for example, by the method described in the column of "(8) Thickness" in the examples described later.

From the viewpoint of ensuring low resilience of the mesh structure of this embodiment, the tanδ at 25°C measured by the dynamic viscoelasticity measuring device of the resin forming the continuous linear body is preferably 0.3 or more, more preferably 0.4 Above, more preferably 0.5 or more, and particularly preferably 0.6 or more. In addition, from the viewpoint of having a sufficient shape recovery speed as a mesh structure, the tan δ is preferably 2.0 or less, and more preferably 1.8 or less. The tanδ can be obtained, for example, by the method described in the column of "(9)tanδ" in the examples described later.

From the viewpoint of eliminating the feeling of bottoming of the mesh structure of the present embodiment, the Shore A hardness of the resin forming the continuous linear body is preferably 40 or more, more preferably 50 or more, and still more preferably 60 or more. In addition, from the viewpoint of ensuring low resilience, the above-mentioned Shore A hardness is preferably 80 or less, and more preferably 70 or less. The Shore A hardness can be obtained by, for example, a method based on the measurement method of the durometer A hardness specified in JIS (Japanese Industrial Standards) K6253-3: 2012.

The mesh structure of the present embodiment is not particularly limited, and can be formed in various shapes, and examples thereof include rectangular parallelepiped shapes and sheet-like shapes.

The use of the mesh structure of this embodiment is preferably a shock-absorbing material, an impact-absorbing material or a cushioning material. That is, the mesh structure of this embodiment may be a shock-absorbing material, an impact-absorbing material, or a cushioning material.

The mesh structure of this embodiment is obtained as follows, for example. The mesh structure system is obtained according to a known method described in Japanese Patent Application Laid-Open No. 7-68061 and the like. For example, firstly, a polystyrene-based thermoplastic elastomer composed of a mixture of the first triblock copolymer and the second triblock copolymer is distributed to the nozzle orifices from a multi-row nozzle having a plurality of orifices. Then, at a spinning temperature higher than the melting point of the polystyrene-based thermoplastic elastomer or the glass transition temperature of the hard segment by 20°C or more and less than 200°C, it is sprayed downward from the nozzle to make the continuous linear bodies in a molten state. Contact and weld to form a three-dimensional structure. The three-dimensional structure of the continuous linear body clamped by the extraction conveying net is cooled by the cooling water in the cooling tank and then extracted, and the water is removed or dried to obtain a mesh structure with smoothing on both sides or one side. In the case of smoothing only one side, it can also be sprayed onto a slanted extraction net, so that the continuous linear bodies are in a molten state to contact each other and welded to form a three-dimensional structure, and the shape is relaxed only on the extraction net surface Cool down. Then, the obtained net-like structure may be dried. Furthermore, the drying treatment of the mesh structure may be an annealing treatment.

Annealing treatment can use hot air drying furnace, hot air circulation furnace and other devices. It is preferable to set the annealing temperature and the annealing time to a predetermined range. The annealing temperature is room temperature or higher, preferably 50°C or higher, more preferably 60°C or higher, and still more preferably 70°C or higher. The upper limit of the annealing temperature is not particularly specified, and it is preferably at least 10°C lower than the melting point or the glass transition temperature of the hard segment. In addition, the annealing treatment is preferably performed in a nitrogen atmosphere. The annealing time is preferably 1 minute or more, more preferably 5 minutes or more, still more preferably 10 minutes or more, and particularly preferably 20 minutes or more.

[Example]

Hereinafter, the present invention will be specifically described by exemplified examples, but the present invention is not limited by these examples. The measurement and evaluation of the characteristic values in the examples were performed as follows. In addition, the size of the sample is based on the size described below, but when the sample is insufficient, the sample size of the possible size is used for measurement.

(1) The existence of polystyrene-based thermoplastic elastomer and the content rate of the polystyrene-based thermoplastic elastomer

The presence of the polystyrene-based thermoplastic elastomer is carried out by infrared absorption spectroscopy, and the content of the polystyrene-based thermoplastic elastomer is measured by GPC. A gel permeation chromatograph "L-7000 series" manufactured by Hitachi, Ltd. was used for the measurement device, TSKgel G4000HXL×2 (manufactured by Tosoh Co., Ltd.) was used for the column, and tetrahydrofuran was used for the solvent. The measurement was performed under the conditions of a flow rate of 1 ml/min, a concentration of 20 mg/10 ml (sample/tetrahydrofuran), and a column temperature of 40°C. The peak area ratio of the polystyrene-based thermoplastic elastomer dissolved in tetrahydrofuran to other components is calculated, and the ratio of the polystyrene-based thermoplastic elastomer in the tetrahydrofuran dissolved component is set as Awt%. The tetrahydrofuran insoluble component was set to Bmg, and it was calculated from the content rate=A(1-B/20).

(2) The existence of styrene and the content of styrene

Regarding the presence of styrene in the network structure and the measurement of the styrene content, the determination of the styrene content was performed by ¹ H-NMR measurement at a resonance frequency of 500 MHz. The measuring device uses AVANCE500 manufactured by BRUKER, and the solvent uses deuterated tetrachloroethane with dimethyl isophthalate added as a reference substance for quality. The sample was dissolved in the solvent at 135°C, and the measurement was performed at 120°C. Take full repetition time. The measurement was carried out in accordance with the above method, and the content of styrene was calculated by the following method.

In the obtained ¹ H-NMR spectrum, when tetrachloroethane is set to 6 ppm, the peak from 6.4 ppm to 7.3 ppm corresponds to the peak of styrene. When analyzing, use the peak integral value of the above-mentioned peak (set to =A). On the other hand, dimethyl isophthalate has peaks around 8.7 (1H), 8.35 (2H), 7.6 (1H), and 4.0 ppm (6H). The peaks that do not overlap with the constituent components of the sample are used. Integral value. Assuming a peak integral value of 7.6ppm (set = B), by the following formula (20.8×A×Y×100)/(194×B×X) (relative to the mass% of the sample)

(Here, the sample amount is X (mg), and the mass of dimethyl phthalate contained in the measurement solution is Y (mg)), and the styrene content is calculated.

(3) The mass ratio of the second triblock copolymer to the first triblock copolymer

The components of the peaks obtained in the above GPC measurement were separated, and ¹ H-NMR spectra were measured for each peak component. According to the peaks of 3,4-bonding (4.8ppm) and 1,2-bonding (5.8ppm) derived from isoprene or a mixture of isoprene and butadiene and 1,4-bonding ( 5.3ppm) peak ratio, calculate the content (content ratio) of 3,4-bond and 1,2-bond. The content (content ratio) of the 3,4-bond and 1,2-bond is 45% or more in the first triblock copolymer and less than 45% in the second triblock copolymer, so Each peak component belongs to the first triblock copolymer and the second triblock copolymer. In the obtained GPC graph, the area ratio of each peak component attributable to the first triblock copolymer and the second triblock copolymer is used to calculate the relative ratio of the second triblock copolymer to the first triblock copolymer. The mass ratio of the segment copolymer.

(4) Compression residual strain at 40℃

Cut the sample into a size of 10cm×10cm×the thickness of _{the sample, clamp the measured sample with the thickness t b} before compression in a jig that can be maintained at 50% compression, and place it at 40°C±2°C. Leave it in the dryer for 22 hours. Then take out the sample, remove the compressive strain, cool it at room temperature (25℃) and calculate the compressed thickness t _a after being left for 30 minutes, and calculate the compressive residual strain at 40℃ from the formula (t _b -t _a )/t _{b ×100} ：Unit% (average value of n=3). Here, the thickness t _b before compression and the thickness t _a after compression are measured by measuring the height of each sample before and after compression, and the average value of the height is taken as the thickness.

(5) Hysteresis loss

Cut the sample into a size of 10cm×10cm×the thickness of the sample, and place it in an environment of 23℃±2℃ for 24 hours under no-load conditions. Use the universal testing machine under the environment of 23℃±2℃ (Japanese and English) (Instron Universal Testing Machine manufactured by Instron Japan Co., Ltd.), the sample is placed on a pressure plate of φ50mm and thickness of 3mm with the sample as the center, at a speed of 10mm/min Start to compress the center of the sample, and measure the thickness when the load is 0.3N±0.05N detected by the universal testing machine as the thickness of the hardness tester. Set the position of the pressure plate at this time to the zero point, compress it to 75% of the thickness of the durometer at a speed of 100mm/min, and return the pressure plate to the zero point at the same speed under the condition of no hold time. This state is maintained for 4 minutes (the first stress-strain curve). After being held at the zero point for 4 minutes, compress to 75% of the durometer thickness at a speed of 100mm/min, and return to the zero point at the same speed under the condition of no hold time (second stress-strain curve).

Referring to Fig. 1, in the second stress-strain curve of Fig. 1(a), set the compressive energy (WC) represented by the stress and strain during the second compression of Fig. 1(b), and the second stress-strain curve of Fig. 1(c) The compressive energy (WC') indicated by the stress-strain curve during the second decompression is based on the following formula. Hysteresis loss (%)=(WC-WC')/WC×100: unit%

WC=ʃPdT (the amount of work done when compressed from 0% to 75%)

WC'=ʃPdT (the amount of work done when depressurizing from 75% to 0%)

Find the hysteresis loss.

To put it simply, the above-mentioned hysteresis loss can be calculated by data analysis using a personal computer after obtaining the stress-strain curve as shown in Figure 1, for example. In addition, the area of the oblique line portion is set to WC, and the area of the mesh portion is set to WC', and it is calculated from the weight of the portion minus the difference between the areas (n=3 average value).

(6) Compression deflection coefficient

Cut the sample into a size of 10cm×10cm×the thickness of the sample. After placing it in an environment of 23℃±2℃ without load for 24 hours, use the universal testing machine under the environment of 23℃±2℃ (Japan Instron Japan Co., Ltd. (Instron Japan Co., Ltd.) manufactured the Instron universal testing machine), the φ50mm, thickness 3mm pressure plate is placed in the center of the sample, and the sample is placed at 10mm/min The speed starts to compress the center of the sample, and the thickness when the load is 0.3N±0.05N detected by the universal testing machine is measured as the thickness of the hardness tester. Taking the position of the pressing plate at this time as the zero point, after compressing to 75% of the thickness of the durometer at a speed of 100mm/min, return the pressing plate to the zero point at a speed of 100mm/min, and keep it in this state for 4 minutes. After 4 minutes, it is compressed to 25% and 65% of the thickness of the durometer at a speed of 100mm/min, and the load at this time is measured as the hardness at 25% compression H ₂₅ and the hardness at 65% compression H ₆₅ : unit N/ φ50 (average value of n=3). Using the thus obtained 25% compression hardness H ₂₅ and 65% compression hardness H ₆₅ , the following formula (compression deflection coefficient)=H ₆₅ /H ₂₅ : (average value of n=3)

Calculate the compression deflection coefficient.

(7) Fiber diameter

Cut the sample into a size of 10 cm in the width direction × 10 cm in the length direction × thickness of the sample, and randomly collect 10 linear bodies with a length of about 5 mm in the thickness direction from the cut section. For the collected linear body, focus an optical microscope on the fiber diameter measurement site (the site where the fiber diameter is measured) at an appropriate magnification, and measure the thickness of the fiber observed from the fiber side (fiber side). Furthermore, the surface of the net-like structure may be flattened in order to obtain smoothness, and the fiber cross section (fiber cross section) may be deformed. Therefore, samples are not collected within 2 mm from the surface of the mesh structure (surface of the mesh structure).

(8) Thickness

Cut out 4 samples with a size of 10 cm in the width direction×10 cm in the length direction×the thickness of the sample, and leave them for 24 hours without load. Then, with the solid section fiber surface side (the solid section fiber surface side) facing upwards, use the FD-80N type thickness gauge manufactured by the polymer meter to measure the height of each sample using a circular gauge ^{with an area of 15 cm 2 to obtain} Take the average of 4 samples as the thickness.

(9)tanδ

The sample was formed into a sheet sample with a thickness of 300 μm by hot pressing at a set temperature of 230° C., and the sheet sample was cut out with a length of 23 mm × a width of 5 mm. Using a dynamic viscoelasticity measuring device (Rheogel-E-4000 manufactured by UBM), the two ends of the long side of the cut sheet sample were fixed by a tensile jig with 4mm portions at each end, at 30Hz, heating rate 2℃/ Measured in min to obtain the tanδ (ratio E"/E' of the loss elastic modulus E" to the storage elastic modulus E') at 23°C.

(10) Shore A hardness

The hardness is measured in accordance with the hardness tester A hardness measurement method specified in JIS K6253-3: 2012.

(Synthesis example 1)

In a 5L autoclave, 1800 g of cyclohexane, 30 g of styrene monomer and 0.32 g of n-butyl lithium were added, and polymerized at 60°C for 1 hour, and then 162 g of isoprene monomer was added, and polymerized at 60°C for 1 hour. Finally, 30 g of styrene monomer was added and polymerized at 60°C for 1 hour. The same amount of methanol is added to the active polymer solution to deactivate the solution, and then precipitate in a large amount of methanol, thereby recovering the isoprene-containing polystyrene-based thermoplastic elastomer (S-1). The obtained isoprene-containing polystyrene-based thermoplastic elastomer (S-1) has a styrene content of 30% by mass and a weight average molecular weight of 170,000. The term "isoprene-containing polystyrene-based thermoplastic elastomer (S-1)" here refers to the first triblock copolymer.

(Synthesis example 2)

Add 1800 g of cyclohexane, 67.5 g of styrene monomer and 0.5 g of n-butyl lithium to a 5L autoclave, polymerize at 60°C for 1 hour, then add 315 g of 1,3-butadiene monomer, and polymerize at 60°C 1 hour. Finally, 67.5 g of styrene monomer was added and polymerized at 60°C for 1 hour. The same amount of methanol is added to the active polymer solution to deactivate the solution, and then precipitate in a large amount of methanol, thereby recovering the butadiene-containing polystyrene-based thermoplastic elastomer (S-2). The obtained butadiene-containing polystyrene-based thermoplastic elastomer (S-2) has a styrene content of 30% by mass and a weight average molecular weight of 270,000. The term "butadiene-containing polystyrene-based thermoplastic elastomer (S-2)" here refers to the second triblock copolymer.

(Example 1)

Use the following nozzle. The nozzle is the effective surface of the nozzle with a length of 100cm in the width direction and a length of 62.4mm in the thickness direction. Staggered arrangement with 5.2mm spacing between holes in the direction. That is, the shape of the effective surface of the nozzle is 100 cm in the width direction and 62.4 mm in the thickness direction. In addition, the orifices are solid-formed orifices with an outer diameter of 0.5 mm, and the arrangement of the orifices is a staggered arrangement with a pitch of 6 mm in the width direction and a pitch of 5.2 mm in the thickness direction. So that the polystyrene-based thermoplastic elastomer (S-1) containing isoprene becomes 43.3% by mass, the polystyrene-based thermoplastic elastomer (S-2) containing butadiene becomes 21.7% by mass, and the paraffin-based process Oil (weight average molecular weight: 750) becomes 20% by mass, hydrogenated terpene resin (softening point: 150°C) becomes 5% by mass, polypropylene (tensile modulus of elasticity: 2000 MPa, MFR (Melt Flow Rate; melt flow rate) ) (Measured at 230°C in accordance with JIS K7210-1: 2014): 45 g/10 min) is measured so that it becomes 10% by mass, and is sufficiently mixed in a pellet state to be used as a raw material. The resulting mixture of raw materials was sprayed below the nozzle in a molten state at a spinning temperature (melting temperature) of 200°C with a single-hole spray rate of 1.5 g/min. Here, the structure below the nozzle is as follows. Cooling water is placed 21cm below the nozzle surface. Between the nozzle and the cooling water, there is a heat preservation cylinder with a length of 50mm directly below the nozzle. A stainless steel endless net with a width of 300mm is placed on the water surface in parallel with an opening width of 50mm. A pair of extraction conveyor belts are arranged in a partially exposed way. According to the above-mentioned structure, the jet in the molten state is bent to form a loop, and the contact portion is welded to form a three-dimensional network structure. While sandwiching both sides of the net-like structure obtained in the molten state with the extraction conveyor belt, it was introduced into the cooling water at a speed of 1.0 m per minute to solidify and flatten both sides. Then, it was cut to a predetermined size and annealed with hot air at 70°C for 30 minutes to obtain a mesh structure. For the obtained net-like structure, various physical property values were obtained in accordance with the above (1) to (10). The results are summarized in Table 1.

(Example 2)

It is measured so that the isoprene-containing polystyrene-based thermoplastic elastomer (S-1) becomes 50.0% by mass and the butadiene-containing polystyrene-based thermoplastic elastomer (S-2) becomes 15.0% by mass, Except for this, a mesh structure was obtained in the same manner as in Example 1. With respect to the obtained net-like structure, various physical property values were obtained in the same manner as in Example 1. The results are summarized in Table 1.

(Example 3)

It is measured so that the isoprene-containing polystyrene-based thermoplastic elastomer (S-1) becomes 38.2% by mass and the butadiene-containing polystyrene-based thermoplastic elastomer (S-2) becomes 26.8% by mass, Except for this, a mesh structure was obtained in the same manner as in Example 1. With respect to the obtained net-like structure, various physical property values were obtained in the same manner as in Example 1. The results are summarized in Table 1.

(Example 4)

It is measured so that the isoprene-containing polystyrene-based thermoplastic elastomer (S-1) becomes 21.7% by mass and the butadiene-containing polystyrene-based thermoplastic elastomer (S-2) becomes 43.3% by mass, Except for this, a mesh structure was obtained in the same manner as in Example 1. With respect to the obtained net-like structure, various physical property values were obtained in the same manner as in Example 1. The results are summarized in Table 1.

(Comparative example 1)

Except for measuring so that the isoprene-containing polystyrene-based thermoplastic elastomer (S-1) may become 100% by mass, a mesh structure was obtained in the same manner as in Example 1. With respect to the obtained net-like structure, various physical property values were obtained in the same manner as in Example 1. The results are summarized in Table 1.

(Comparative example 2)

Except for measuring so that the butadiene-containing polystyrene-based thermoplastic elastomer (S-2) may become 100% by mass, a mesh structure was obtained in the same manner as in Example 1. With respect to the obtained net-like structure, various physical property values were obtained in the same manner as in Example 1. The results are summarized in Table 1.

(Comparative example 3)

To make the polystyrene-based thermoplastic elastomer (S-2) containing butadiene 20% by mass, soft polypropylene (hardness (according to ASTM (American Society for Testing and Materials; American Society for Testing and Materials) D2240 at 23°C) Measured): 61A, MFR (melt flow rate) (measured at 190°C in accordance with JIS K7210-1: 2014): 17g/10min) is measured so that it becomes 80% by mass, except that it is the same as in Example 1 The way to obtain a mesh structure. With respect to the obtained net-like structure, various physical property values were obtained in the same manner as in Example 1. The results are summarized in Table 1.

(Comparative Example 4)

So that the isoprene-containing polystyrene thermoplastic elastomer (S-1) is 65% by mass, the paraffin-based process oil (weight average molecular weight: 750) is 20% by mass, and the hydrogenated terpene resin (softening point: 150) ℃) becomes 5 mass%, polypropylene (tensile modulus of elasticity: 2000MPa, MFR (melt flow rate) (measured at 230℃ in accordance with JIS K7210-1: 2014): 45g/10min) becomes 10 mass% Except for the measurement, the mesh structure was obtained in the same manner as in Example 1. With respect to the obtained net-like structure, various physical property values were obtained in the same manner as in Example 1. The results are summarized in Table 1.

(Comparative Example 5)

To make the butadiene-containing polystyrene-based thermoplastic elastomer (S-2) 75% by mass, paraffin-based process oil (weight average molecular weight: 750) to 10% by mass, hydrogenated terpene resin (softening point: 150°C) ) Becomes 5 mass%, polypropylene (tensile modulus of elasticity: 2000MPa, MFR (melt flow rate) (measured at 230°C in accordance with JIS K7210-1: 2014): 45g/10min) becomes 10 mass% Except for this, a mesh structure was obtained in the same manner as in Example 1. With respect to the obtained net-like structure, various physical property values were obtained in the same manner as in Example 1. The results are summarized in Table 1.

(Comparative Example 6)

To make the polystyrene-based thermoplastic elastomer (S-2) containing butadiene 15% by mass, soft polypropylene (hardness (measured at 23°C in accordance with ASTM D2240): 61A, MFR (melt flow rate) ( Measured at 190°C in accordance with JIS K7210-1: 2014): 17g/10min) becomes 80% by mass, and paraffin-based process oil (weight average molecular weight: 750) becomes 5% by mass. Other than that, the same as in the examples 1 Obtain a mesh structure in the same way. With respect to the obtained net-like structure, various physical property values were obtained in the same manner as in Example 1. The results are summarized in Table 1.

(Comparative Example 7)

In order to make the polystyrene-based thermoplastic elastomer (S-1) containing isoprene to 66.7 mass%, and the polystyrene-based thermoplastic elastomer (S-2) containing butadiene to 13.3 mass%, the paraffin-based process Oil (weight average molecular weight: 750) becomes 10% by mass, hydrogenated terpene resin (softening point: 150°C) becomes 5% by mass, polypropylene (tensile modulus: 2000 MPa, MFR (melt flow rate)) (according to JIS K7210-1: 2014 was measured at 230°C): 45 g/10 min) was measured so as to be 5 mass%, and except that the mesh structure was obtained in the same manner as in Example 1. With respect to the obtained net-like structure, various physical property values were obtained in the same manner as in Example 1. The results are summarized in Table 1.

(Comparative Example 8)

So that the polystyrene-based thermoplastic elastomer (S-1) containing isoprene becomes 22.9% by mass, the polystyrene-based thermoplastic elastomer (S-2) containing butadiene becomes 57.1% by mass, and the paraffin-based process Oil (weight average molecular weight: 750) becomes 10% by mass, hydrogenated terpene resin (softening point: 150°C) becomes 5% by mass, polypropylene (tensile modulus: 2000 MPa, MFR (melt flow rate)) (according to JIS K7210-1: 2014 was measured at 230°C): 45 g/10 min) was measured so as to be 5 mass%, and except that the mesh structure was obtained in the same manner as in Example 1. With respect to the obtained net-like structure, various physical property values were obtained in the same manner as in Example 1. The results are summarized in Table 1.

If referring to Table 1, the network structure system of Examples 1 to 4 contains 45% by mass or more of polystyrene-based thermoplastic elastomer, and the styrene content is 5% by mass or more and 40% by mass or less. The ratio of the block copolymer to the first triblock copolymer is in the range of 0.25 or more and 0.75 or less. By having such a configuration, the hysteresis loss of the mesh structure system of Examples 1 to 4 is 35% or more, the tanδ is 0.3 or more, and the Shore A hardness is 80 or less, so it has low resilience. In addition, the mesh structure system of Examples 1 to 4 has a 40°C compressive residual strain of 40% or less, so it has excellent durability, a compressive deflection coefficient of 10 or less, a thickness of 5mm or more, and a Shore A hardness of 40 or more , So there is no sense of bottoming out. Since the mesh structure of Comparative Example 1 does not contain the second triblock copolymer, the Shore A hardness is greater than 80, so it cannot be said to have low resilience, and the compressive residual strain at 40°C is greater than 40, resulting in poor durability. Since the mesh structure of Comparative Example 2 does not contain the first triblock copolymer, the hysteresis loss is less than 35% and the tanδ is less than 0.3, so it is not low resilience, and the compression deflection coefficient is greater than 10, so it has a bottoming feeling. The mesh structure of Comparative Example 3 has a styrene content of less than 5% by mass and does not contain the first triblock copolymer, so the tanδ is less than 0.3 and the Shore A hardness is greater than 80, so it is not low resilience, and 40 ℃ Compression residual strain is greater than 40, so the durability is poor.

It should be understood that the embodiments and examples disclosed herein are illustrative and non-limiting in all aspects. The scope of the present invention is indicated by the scope of the patent application rather than the above description, and includes all changes within the meaning and scope equivalent to the scope of the patent application.

Claims (10)

A network structure with a three-dimensional random loop joint structure composed of continuous linear bodies; the aforementioned continuous linear system is composed of a resin containing polystyrene-based thermoplastic elastomer as a main component of 45% by mass or more The fiber; the aforementioned polystyrene-based thermoplastic elastomer is a mixture of the first triblock copolymer and the second triblock copolymer; the aforementioned first triblock copolymer is composed of a styrene polymer block-isoprene Ethylene polymer block-styrene polymer block; the aforementioned second triblock copolymer is composed of styrene polymer block-butadiene polymer block-styrene polymer block and styrene polymer It is composed of at least any one of the polymer block-butadiene and isoprene copolymer block-styrene polymer block. The network structure described in claim 1, wherein the content of styrene is 5 mass% or more and 45 mass% or less. The network structure according to claim 1 or 2, wherein the mass ratio of the second triblock copolymer to the first triblock copolymer is 0.25 or more and 2.20 or less. The mesh structure as described in claim 1 or 2, wherein the compressive residual strain at 40°C is 40% or less. The mesh structure described in claim 1 or 2, wherein the hysteresis loss due to compression is 35% or more. The mesh structure as described in claim 1 or 2, wherein the compression deflection The coefficient is 10 or less. The mesh structure according to claim 1 or 2, wherein the fiber diameter of the continuous linear body is 0.1 mm or more and 3.0 mm or less, and the thickness of the mesh structure is 5 mm or more and 300 mm or less. The network structure according to claim 1 or 2, wherein the tanδ of the resin at 25°C measured with a dynamic viscoelasticity measuring device is 0.3 or more. The network structure according to claim 1 or 2, wherein the Shore A hardness of the resin is 40 or more. The mesh structure according to claim 1 or 2, wherein the use of the mesh structure is a shock-absorbing material, an impact-absorbing material, or a cushioning material.

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