JP2022057756A - Sustainable network structure - Google Patents

Abstract

To provide a network structure that has low environmental load and excellent dewatering property and allows contaminations adhering to the network structure to be easily removed.SOLUTION: A network structure has a three-dimensional random loop joint structure formed of a continuous linear body and has apparent density of 0.005 g/cm3 to 0.30 g/cm3 and thickness of 10 mm to 100 mm. The continuous linear body has a melting point of 80 to 180°C and MFR of 6 to 60 g/10 min. The network structure contains at least one type of biodegradable thermoplastic resin (a) selected from polybutylene succinate, poly(butylene succinate/adipate), and poly(butylene adipate/terephthalate). The network structure has the 70°C-compression residual strain of 35% or less.SELECTED DRAWING: None

Description

The present invention relates to a reticulated structure suitable for daily sanitary products such as scrubs and brushes, which are relatively frequently disposable, and draining products.

Currently, daily sanitary products such as scrubbing brushes, sponges, and brushes include scrubbing brushes made of coconut fiber, brushes made by bundling monofilaments such as polypropylene and polyethylene, and sponges made of polyurethane or cellulose. Widely used.

"Tawashi" made from palm fiber has a small environmental load because it uses natural materials. However, a typical "sawashi" made by bundling palm fibers and bending them into an oval shape is knitted with metal to fix the shape. Therefore, it is necessary to separate the metal when disposing of it. Further, although the scrubbing brush has an excellent cleaning effect, the removed stains are likely to be caught between the fibers of the scrubbing brush, and it may be necessary to remove the transferred stains.

On the other hand, a "brush" in which monofilaments such as polypropylene are bundled does not have biodegradability and may cause marine microplastics. Further, although the cleaning effect is excellent as in the case of the scrubbing brush using palm fibers, the removed stains are easily caught between the scrubbing brush fibers, and it may be necessary to remove the transferred stains.

The sponge is a rubber in which a foaming agent is mixed and the rubber is made into a porous structure by a gas generated by thermal decomposition of the foaming agent. The unit of the bubble structure that constitutes the foam is called a cell.
Polyurethane sponges are not biodegradable and have the risk of becoming marine microplastics. Further, although the cleaning effect is excellent as in the case of scrubbing brush using palm fiber, the removed dirt may be caught inside the cell and it may take time to remove the transferred dirt.

Furthermore, since the inside of the cell retains water for a relatively long time, there are hygienic problems such as Escherichia coli and mold growing from this water. In order to prevent these, it is generally sterilized with a chemical such as chlorine, but there is also a problem of growth of resistant bacteria, which causes a problem in terms of hygiene.
In order to reduce the water retention of this cell, consideration has been made to increase the size of the cell and it has been commercialized. However, although the drainage property has improved, the water retention problem has not been solved yet. Further, when the cell size is increased, the rigidity of the sponge may be lowered and the cleaning effect may be lowered.

In addition, polyurethane is generally difficult to recycle. Therefore, it has been pointed out that there are problems such as large damage to the incinerator and costly removal of toxic gas during incineration. Therefore, it is often disposed of in landfills, but there is also the problem that the landfill site is limited and the cost is high because it is difficult to stabilize the ground. In addition, although it is excellent in processability, various problems such as pollution problems of chemicals used during manufacturing, residual chemicals after foaming, and odors associated therewith have been pointed out.

Patent Documents 1 and 2 disclose a network structure made of a thermoplastic elastomer system. The above-mentioned network structure is excellent in terms of drainability, resistance to settling, and transferable stains can be easily washed away. However, since the fiber diameter is relatively large, it is difficult to remove dirt that has entered the corners. Moreover, the above-mentioned thermoplastic elastomer does not have biodegradability.

Patent Document 3 discloses a network structure made of a polyolefin. This has the above-mentioned drainability and appropriate hardness, and the transferred stains can be easily washed away, which is excellent from these viewpoints. However, it is not sufficient in terms of settling resistance and does not have biodegradability.

Patent Document 4 discloses a biodegradable aquatic plant support for greening, an aquatic plant structure using the same, and a structure for floating islands. This reticulated structure uses polylactic acid and has biodegradation, but it is hard and brittle, so it is not suitable for this application.

Against this background, there has been a demand for an environment-friendly network structure having drainage property, resistance to settling, convenience in which transferred stains can be easily washed away, and biodegradability.

Japanese Unexamined Patent Publication No. 2004-313323 Japanese Unexamined Patent Publication No. 2014-194099 JP-A-2015-067932 Japanese Unexamined Patent Publication No. 2001-322236

An object of the present invention is to provide a network structure having a small environmental load, excellent drainage property, and easy removal of transferred stains.

The present invention that can solve the above problems is as follows.
1. 1. It is a network structure having a three-dimensional random loop joint structure composed of continuous linear bodies, having an apparent density of 0.005 g / cm ³ to 0.30 g / cm ³ , and a thickness of 10 mm to 100 mm. ,
The continuous striatum has a melting point of 80 to 180 ° C., an MFR of 6 to 60 g / 10 min, and is selected from polybutylene succinate, poly (butylene succinate / adipate), and poly (butylene adipate / terephthalate). , Containing at least one biodegradable thermoplastic resin (a),
The network structure is a network structure having a 70 ° C. compression residual strain of 35% or less.
2. 2. Polylactic acid, (polylactic acid / polybutylene succinate) block copolymer, polycaprolactone, poly (caprolactone / butylene succinate), poly (butylene succinate / carbonate), poly (ethylene terephthalate / succinate), poly (tetramethylene adipate) / Telephthalate), polyethylene succinate, polyvinyl alcohol, polyglycolic acid, which contains at least one biodegradable thermoplastic resin (b), and the biodegradable resin (a) and the biodegradable resin (a). The network structure according to 1 above, which contains 80% by mass or more of the mixture of b) with respect to the thermoplastic resin composition on a mass basis.
3. 3. The reticulated structure according to 1 or 2, wherein the continuous linear body has a circular cross-sectional shape and a fiber diameter of 0.1 mm to 0.8 mm.
4. The continuous linear body has an irregular cross-sectional shape, has at least three or more equivalent curvatures on the outer peripheral portion, and has a fiber diameter or twice the radius of curvature thereof of 0.1 mm or more and 0.8 mm or less. The network structure according to 1 or 2 above.
5. The reticulated structure according to 4 above, wherein the continuous linear body has a trilobal shape or a triangular cross section.
6. The network structure according to any one of 1 to 5 above, which is used for daily hygiene products and draining products.

Since the network structure of the present invention uses a biodegradable thermoplastic resin, the environmental load is small. Further, since it is a net-like structure having an appropriate hardness, it has good drainability and is hygienic, and it is easy to wash away the transferred stains. Therefore, it is particularly suitable for daily hygiene products such as scrubs and brushes, which are relatively frequently disposable, and draining products, and can also be used as cushioning materials, cushions, and the like.

Hereinafter, the present invention will be described in detail.
The network structure of the present invention has a three-dimensional random loop joint structure composed of continuous linear bodies, has an apparent density of 0.005 g / cm ³ to 0.30 g / cm ³ , and a thickness of 10 mm to 100 mm. The continuous linear body has a melting point of 80 to 180 ° C. and an MFR of 6 to 60 g / 10 min, polybutylene succinate, poly (butylene succinate / adipate), poly (butylene adipate / terephthalate). It is made of at least one biodegradable thermoplastic resin selected from the above, and the network structure has a 70 ° C. compression residual strain of 35% or less.

The reticulated structure of the present invention uses at least one biodegradable thermoplastic resin selected from polybutylene succinate, poly (butylene succinate / adipate), and poly (butylene adipate / terephthalate). The biodegradable thermoplastic resin can be obtained by a known polymerization method.

Polybutylene succinate is polymerized by a known method using succinic acid and butanediol as raw materials. Polybutylene succinate adipate is polymerized by a known method using succinic acid, adipic acid and butanediol as raw materials. Poly (butylene adipate / terephthalate) is polymerized by a known method using adipic acid, terephthalic acid, and butanediol as raw materials. Further, if necessary, a chain extender, a terminal blocker, an antioxidant and the like are appropriately used.
Although petroleum-derived monomers can be used as these raw materials, it is preferable to use biomass-derived monomers from the viewpoint of reducing the environmental load. Specifically, the resin listed in the positive list of the classification number A (biomass plastic) of the Japan Bioplastics Association is particularly preferable.

If necessary, two or more of the above biodegradable thermoplastic resins can be blended.
In addition to the above-mentioned biodegradable thermoplastic resin (a), a polyester-based elastomer having no biodegradability, polylactic acid having biodegradability, polycaprolactone, etc. may be used to the extent that the biodegradability is not impaired. By containing 10% by mass or less of another thermoplastic resin in the thermoplastic resin composition on a mass basis, physical properties such as hardness can be adjusted.
If the content of the other thermoplastic resin is more than 10% by mass on a mass basis with respect to the thermoplastic resin composition, the die well becomes poor and it becomes difficult to form a network structure having excellent quality, which is not preferable. As the other thermoplastic resin, an aliphatic polyester is preferable from the viewpoint of mixing property at the time of blending.

The thermoplastic resin composition described in the present invention includes one or more types of thermoplastic resins and, if necessary, functional imparting materials (antioxidants, heat resistant agents, flame retardants, lubricants, particles, etc.). It means a composition containing a constituent component.

The network structure of the present invention requires at least one biodegradable thermoplastic resin (a) selected from polybutylene succinate, poly (butylene succinate / adipate), and poly (butylene adipate / terephthalate). As any other biodegradable thermoplastic resin (b), including, polylactic acid, (polylactic acid / polybutylene succinate) block copolymer, polycaprolactone, poly (caprolactone / butylene succinate), poly (butylene succinate). / Carbonate), poly (ethylene terephthalate / succinate), poly (tetramethylene adipate / terephthalate), polyethylene succinate, polyvinyl alcohol, polyglycolic acid, etc., biodegradable thermoplastic resin (a) alone or biodegradable heat As a mixture of the thermoplastic resin (a) and the biodegradable thermoplastic resin (b), it has a three-dimensional random loop bonding structure composed of a continuous linear body containing at least 80% by mass with respect to the thermoplastic resin composition. It is a network structure.

The ratio of the biodegradable thermoplastic resin is more preferably 85% by mass or more, still more preferably 95% by mass or more, still more preferably 95% by mass or more, based on the mass of the thermoplastic resin composition constituting the continuous linear body. Is 98% by mass or more, most preferably 99% by mass or more.

As the biodegradable thermoplastic resin used in the present invention, a biodegradable synthetic polymer compound listed in the positive list of classification number A-1 of green plastic (biodegradable plastic) of the Japan Bioplastics Association is particularly preferable.

At least one biodegradable thermoplastic selected from polybutylene succinate, poly (butylene succinate / adipate), and poly (butylene adipate / terephthalate) used for the continuous striatum constituting the network structure of the present invention. The thermoplastic resin composition containing the resin (a) has an MFR of 6 to 60 g / 10 min. When the MFR is less than 6 g / 10 min, the melt viscosity becomes too high and it becomes difficult to reduce the fiber diameter of the continuous striatum. As a result, it becomes difficult to remove dirt.

On the other hand, when the MFR exceeds 60 g / 10 min, the compression residual strain, which is a measure of heat resistance, tends to deteriorate. From such a viewpoint, the MFR is preferably 6 g / 10 min or more, more preferably 8 g / 10 min or more, still more preferably 10 g / 10 min or more. The MFR is preferably 60 g / 10 min or less, more preferably 50 g / 10 min or less, further preferably 40 g / 10 min or less, and most preferably 30 g / 10 min or less.

However, commercially available biodegradable resins are not limited to resins that satisfy the range of MFR specified in the present invention. In this case, the MFR of the resin can be arbitrarily adjusted by adjusting the water content of the biodegradable resin and hydrolyzing the resin during melt extrusion.

At least one biodegradable thermoplastic selected from polybutylene succinate, poly (butylene succinate / adipate), and poly (butylene adipate / terephthalate) used for the continuous striatum constituting the network structure of the present invention. The resin (a) preferably has a melting point of 80 to 180 ° C. If the melting point of the resin is less than 80 ° C., the network structure may be deformed when it comes into contact with a high-temperature liquid such as hot water or when it is dried by warm air from a dryer or the like. Therefore, the melting point of the resin is preferably 80 ° C. or higher, more preferably 85 ° C. or higher, further preferably 90 ° C. or higher, and most preferably 100 ° C. or higher. When the network structure of the present invention is used for daily hygiene products and draining products, it is sufficient that the melting point of the resin is 180 ° C. or lower.

The continuous striatum constituting the network structure of the present invention preferably has an endothermic peak below the melting point in the melting curve measured by a differential scanning calorimeter. Those having an endothermic peak below the melting point have improved hardness and heat resistance and sag resistance of the continuous striatum as compared with those having no endothermic peak. For example, the polybutylene succinate, poly (butylene succinate / adipate), and poly (butylene adipate / terephthalate) resins used in the present invention are continuously subjected to annealing treatment at a temperature at least 10 ° C. lower than the melting point after fusion heat bonding. The hardness of the striatum is further improved. The annealing treatment may be performed by heat-treating the sample at a temperature at least 10 ° C. lower than the melting point of the resin, and the annealing treatment can be performed after molding into a three-dimensional network structure. The reticulated structure subjected to such heat treatment more clearly develops an endothermic peak at a temperature of room temperature or higher and lower than the melting point on the melting curve measured by a differential scanning calorimeter. If the annealing treatment is not performed, the endothermic peak does not clearly appear on the melting curve above room temperature and below the melting point. By analogy with this, it is considered that the annealing treatment forms a metastable intermediate phase in which the hard segments are rearranged, and the heat resistance and sag resistance are improved. As a method of utilizing the effect of improving the sag resistance in the present invention, it is useful for realizing a daily hygiene product or a cushioning material having the required durability.

The continuous linear body constituting the network structure of the present invention preferably has a D durometer hardness of 30 to 80. By adjusting the D durometer hardness to 30 or more, the hardness becomes appropriate and the cleaning function by scraping is improved. The D durometer hardness of the continuous linear body is more preferably 35 or more, further preferably 40 or more, and particularly preferably 45 or more.
Further, by adjusting the hardness of the D durometer to 80 or less, it is possible to suppress the hardness from becoming too hard, and the hardness becomes less likely to become brittle. The D durometer hardness is more preferably 75 or less, and particularly preferably 70 or less.

The reticulated structure of the present invention has a 70 ° C. compression residual strain of 35% or less, preferably 30% or less, and more preferably 25% or less. Further, the 70 ° C. compression residual strain may be practically 1% or more. When the 70 ° C. compression residual strain is 35% or less, durability and heat resistance can be satisfied.

The 70 ° C. compression residual strain is widely used as an index showing durability. With thermoplastic resins, especially elastomers, it has been difficult with conventional techniques to achieve both hardness and durability. This is a fundamental challenge due to the structure of the elastomer. Generally, the structure of an elastomer consists of a soft segment and a hard segment, and it is considered that hardness and durability are exhibited by the balance between the two. "Hard" means that the hard segment is strong or has a high proportion. That is, the ratio of the soft segment of the hard thermoplastic resin elastomer is relatively low or weak. As a result, it is considered that the durability of the reticulated structure composed of the obtained continuous linear body is insufficient. On the other hand, the opposite case means that it is soft and has excellent durability.

As one of the indexes showing the hardness, D durometer hardness can be mentioned. Further, one of the indexes representing the D durometer hardness and sagging is the 70 ° C. compression residual strain. No method has been found to satisfy both of these requirements. In particular, due to the low durability of the biodegradable resin, it is very difficult to achieve both. As a method for achieving both of these, the mechanism has not yet been clarified, but at least one biodegradation selected from polybutylene succinate, poly (butylene succinate / adipate), and poly (butylene adipate / terephthalate) resin. It has been found that this can be achieved by using a continuous striatum containing a sex thermoplastic resin as a constituent material of a network structure.

The network structure of the present invention can be obtained, for example, as follows. The network structure can be obtained according to a known method described in JP-A-7-68061 and the like. For example, polybutylene succinate, poly (butylene succinate / adipate), and poly (butylene adipate / terephthalate) resins are distributed to the nozzle orifices from a multi-row nozzle having multiple orifices, and the resin (melting point + 20 ° C.) or higher. At a spinning temperature of less than (melting point + 180 ° C.), the resin is discharged downward from the nozzle. Next, in the molten state, the continuous linear bodies are brought into contact with each other and fused to form a three-dimensional network structure, sandwiched between the take-up conveyor nets, and cooled by the cooling water in the cooling tank. Then, the solidified reticular structure is drawn out and drained or dried to obtain a reticular structure having smoothed both sides or one side.
When smoothing only one side, a continuous linear body is discharged onto a take-up net having an inclination, and the continuous linear bodies are brought into contact with each other in a molten state and fused. At that time, it is preferable to cool only the take-up net surface while relaxing the morphology while forming a three-dimensional network structure. The obtained network structure can also be annealed. The drying treatment of the reticulated structure may be an annealing treatment.

In order to obtain the network structure of the present invention, the biodegradable resin used as a raw material may contain a function-imparting material such as an antioxidant or a lubricant. When it is contained in the resin itself, it is preferable to knead various function-imparting materials into the resin at the time of melt extrusion to adjust the content according to the color tone and quality after melting.

Examples of the antioxidant include known phenol-based antioxidants, phosphite-based antioxidants, thioether-based antioxidants, benzotriazole-based UV absorbers, triazine-based UV absorbers, benzophenone-based UV absorbers, and NH-type. Examples thereof include hindered amine-based light stabilizers and N-CH type ₃ hindered amine-based light stabilizers, and it is desirable to contain at least one of them.

Phenolic antioxidants include 1,3,5-tris [[3,5-bis (1,1-dimethylethyl) -4-hydroxyphenyl] methyl] -1,3,5-triazine-2,4. , 6 (1H, 3H, 5H) -trione, 1,1,3-tris (2-methyl-4-hydroxy-5-tert-butylphenyl) butane, 4,4'-butylidenebis (6-tert-butyl-) m-cresol), 3- (3,5-di-tert-butyl-4-hydroxyphenyl) stearyl propionate, pentaerythritol tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate ], Sumilizer AG 80, 2,4,6-tris (3', 5'-di-tert-butyl-4'-hydroxybenzyl) mecitylene and the like.

Phosphite-based antioxidants include 3,9-bis (octadecyloxy) -2,4,8,10-tetraoxa-3,9-diphosphaspiro [5.5] undecane and 3,9-bis (2,6). -Di-tert-butyl-4-methylphenoxy) -2,4,8,10-tetraoxa-3,9-diphosphaspiro [5.5] undecane, 2,4,8,10-tetrakis (1,1-dimethyl) Ethyl) -6-[(2-ethylhexyl) oxy] -12H-dibenzo [d, g] "1,3,2" dioxaphosphosin, tris phosphite (2,4-di-tert-butylphenyl) , Tris (4-nonylphenyl) phosphite, 4,4'-Isopropylidenediphenyl C12-15 alcohol phosphite, diphenyl phosphite (2-ethylhexyl), diphenylisodecylphosphite, triisodecylphosphite, triphenyl phosphite, etc. Can be mentioned.

As thioether-based antioxidants, bis [3- (dodecylthio) propionic acid] 2,2-bis ["3- (dodecylthio) -1-oxopropyloxy" methyl] -1,3-propanediyl, 3,3 '-Ditridecylthiobispropionate and the like.

In order to prevent thermal deterioration of the resin, it is desirable to use a mixture of a phenolic antioxidant and a phosphite-based antioxidant. The content of these two types of antioxidants is preferably 0.05% by mass or more and 1.0% by mass or less based on the mass of the resin.

Examples of the lubricant include hydrocarbon waxes, higher alcohol waxes, amide waxes, ester waxes, metal soap waxes and the like. If necessary, the lubricant may be contained in an amount of 0.5% by mass or less based on the mass of the resin.

In the network structure of the present invention, an abrasive may be contained in the resin, if necessary, in order to improve the detergency. As the abrasive, a known material such as an inorganic substance or an organic substance can be used. For example, examples of the material of the abrasive include silicon dioxide, alumina oxide, chromium oxide, cerium oxide, glass, activated carbon particles, polyethylene, ultra-high molecular weight polyethylene, polypropylene and the like. The method of containing the abrasive in the resin is a known method such as mixing the resin and the abrasive at the time of melt extrusion, dipping or coating in the continuous linear body constituting the obtained network structure, and including the abrasive. The binder can be coated.

Further, the network structure of the present invention can be colored as needed. Pigments and dyes can be used for coloring. Further, they may be contained before melt spinning, or may be dipped or applied to a continuous linear body constituting the obtained network structure to cover it.

The continuous linear body constituting the network structure of the present invention may be a composite linear body in combination with another thermoplastic resin as long as the object of the present invention is not impaired. Examples of the composite form include a composite linear body such as a sheath-core type, a side-by-side type, and an eccentric sheath-core type when the linear body itself is composited.

The network structure of the present invention may be multi-layered as long as the object of the present invention is not impaired. As a multi-layer structure, the surface layer and the back layer may be composed of linear bodies having different fineness, the surface layer and the back layer may be composed of structures having different apparent densities, long-fiber non-woven fabric, short-fiber non-woven fabric, etc. And multi-layered. Examples of the multi-layering method include a method of melting and fixing by heating, a method of adhering with an adhesive, a method of restraining with sewing or a band, and the like.

The cross-sectional shape of the continuous linear body constituting the reticulated structure of the present invention is not particularly limited, but a solid cross section or a modified cross section including a hollow can be used to impart preferable hardness and handleability. In particular, when detergency and drainability are emphasized, for example, a continuous line having a deformed cross section in which the end face of a three-leaf shape such as Y-shaped or s + -shaped has an edge shape and the moment of inertia of area is circularly symmetric. The shape is preferable.

The reticulated structure of the present invention is processed into a molded body from the resin manufacturing process to the extent that the performance is not deteriorated, and at any stage of commercialization, using a known method, deodorant antibacterial property, mildew proof property, and mite proof property. , Deodorant, antibacterial, aromatic, flame-retardant, moisture-absorbing and desorbing, etc. can be imparted.

The reticulated structure of the present invention includes those molded into any shape. For example, plate-shaped, triangular prisms, polygons, cylinders, spheres and structures containing many of them are also included. These molding methods may be molded using a regulating plate at the time of extrusion, or may be performed by a known method such as cutting or heat pressing.

It is desirable that the continuous linear body constituting the network structure of the present invention has a small fiber diameter from the viewpoint of being able to remove all the stains. However, if the fibers are too thin, the hardness of the continuous striatum becomes insufficient, and the detergency for removing stains tends to decrease. Further, if the fiber is too thick, the network structure becomes sparse, the foaming property is lowered, it is difficult to remove the dirt in the corner, and the fiber end face may hit the finger and cause pain. Therefore, it is preferable to set the fiber diameter in an appropriate range.
When the cross-sectional shape of the continuous linear body is a circle, the fiber diameter of the continuous linear body is preferably 0.1 mm or more, more preferably 0.2 mm or more, and particularly preferably 0, from the viewpoint of stain removal property. It is .25 mm or more. On the other hand, the fiber diameter of the continuous linear body is preferably 0.8 mm or less, more preferably 0.7 mm or less, and particularly preferably 0.6 mm or less from the viewpoints of foaming property and removal of existing stains.

As described above, in order to remove dirt, it is preferable to have a fine edge shape in the cross section of the continuous linear body, but if the continuous linear body itself is too thin, the required hardness may be insufficient. There is. One of the measures to solve this problem is to make the cross section of the continuous linear body atypical. That is, by forming a cross section having a fine edge shape, it is possible to remove fine dirt adhering to the edge portion.
Further, since the continuous linear body itself can be thickened to some extent, it is possible to adjust the hardness to a desired level. When the cross-sectional shape of the fiber is atypical cross-section, the structure having at least three or more equal curvature edges on the outside of the fiber cross-section, and the structures having each curvature rotate evenly and with respect to the center of gravity of the fiber cross-section. It is symmetric, and it is preferable that twice the radius of curvature is 0.1 mm or more and 0.8 mm or less. By adjusting twice the radius of curvature to 0.8 mm or less, it becomes easier to remove dirt from the portion that has entered the fine groove. The radius of curvature is more preferably 0.7 mm or less, still more preferably 0.6 mm or less, and particularly preferably 0.5 mm or less. On the other hand, the radius of curvature may be 0.1 mm or more in practice.

The fiber cross section of the continuous linear body is preferably a cross-sectional shape capable of drawing a loop shape. The cross-sectional shape in which a loop can be drawn is the simplest, and includes a circular shape and a hollow structure. In the modified cross section, the outer side of the fiber cross section has edges having at least three or more equal curvatures, and the structure having each curvature is uniform and rotationally symmetric with respect to the center of gravity of the fiber cross section. To describe it in a more general way, with respect to a straight line that is connected to the center of gravity by taking any point around the center of gravity of the fiber cross section, the moments in the straight line direction and the vertical direction are balanced around the center of gravity. It is preferable to have. Specific examples of these include a Y cross section having a three-leaf shape, a triangular shape, and a + cross section having a four-leaf shape.

The apparent density of the reticulated structure of the present invention is 0.005 g / cm ³ to 0.30 g / cm ³ , preferably 0.01 g / cm ³ to 0.20 g / cm ³ , and more preferably 0.02 g / cm. It is in the range of cm ³ to 0.15 g / cm ³ . If the apparent density is less than 0.005 g / cm ³ , the hardness required to remove dirt will be insufficient. On the other hand, if the apparent density exceeds 0.30 g / cm ³ , it may become too hard and unsuitable as a scrubbing brush.

The thickness of the network structure of the present invention is preferably 10 mm or more, more preferably 15 mm or more, still more preferably 20 mm or more. If the thickness is less than 10 mm, it may be too thin to handle when used as a cushioning material. The upper limit of the thickness is preferably 100 mm or less, more preferably 80 mm or less, still more preferably 60 mm or less in view of the manufacturing apparatus.

The network structure of the present invention thus obtained is an excellent network structure having biodegradation, good hardness, resistance to settling, and handleability. For example, when used as a shaving, the microplastic generated during use also has biodegradation and is less likely to cause a microplastic problem, and even when the product has reached the end of its life and is landfilled, the biodegradability causes a microplastic problem. Is expected to be less likely to occur. Within the scope of the present invention, these problems can be solved.

Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto. The measurement and evaluation of the characteristic values in the examples were performed as follows. The standard size of the sample is as described below, but when the sample is insufficient, the measurement was performed using the sample size of the possible size.

(1) Fiber diameter A sample is cut into a size of 8 cm × 10 cm, and linear bodies are collected from each of the reticulated structures at a length of about 5 mm from 10 points. The fiber diameter of the collected linear body is measured by focusing on the fiber diameter measurement point with an optical microscope at an appropriate magnification. (Mean value of n = 10)

(2) D-durometer hardness A D-type durometer was pressed against the center of the fiber of the reticulated structure, and the value within 1 second was read. The test site was 20 ± 2 ° C. and the relative humidity was 65 ± 4%, and the sample was placed in this test environment for at least 1 hour and measured after the temperature became stable. However, if the fiber diameter is 0.4 mm or less and the needle cannot be pressed, or if the needle is stuck in a recess in the irregular cross section and cannot be measured accurately, or if the fiber diameter is too small and the needle penetrates the fiber. When I picked up the hardness of the desk, I made a smooth plate with a thickness of 2 to 3 mm and read the hardness. (Mean value of n = 5 respectively)

(3) Sample thickness and apparent density After cutting the sample into a size of 8 cm x 10 cm and leaving it for 24 hours with no load, use an FD-80N type thickener manufactured by Polymer Meter to measure the height at one center. Measure to obtain the sample thickness. The sample weight is measured by placing the above sample on an electronic balance. The apparent density is obtained by determining the volume from the sample thickness and dividing the weight of the sample by the volume. (Mean value of n = 3 respectively)

(4) Melting point (Tm)
Using the differential scanning calorimeter Discovery DSC25 manufactured by TA Instruments, the sample weight was weighed to 2.0 mg ± 0.1 mg, and the endothermic peak was measured from the endothermic heat absorption curve measured at a temperature rise rate of 20 ° C./min under a nitrogen atmosphere. The (melting peak) temperature was determined.

(5) MFR (melt flow rate)
The measurement was carried out by chopping the network structure into small pieces and vacuum-drying the raw material at 80 ° C. for 2 hours or more, and then quickly measuring the melt flow rate (MFR) so as not to contain as much moisture in the air as possible. The measurement method was performed in accordance with ISO1133. The measurement temperature was 190 ° C. and the load was 2.16 kg.

(6) 70 ° C. compression residual strain A sample is cut into a size of 10 cm × 8 cm, and the thickness (c) before treatment is measured by the method described in (2). The sample whose thickness has been measured is sandwiched between jigs that can be held in a 50% compressed state, placed in a dryer set at 70 ° C., and left to stand for 22 hours. After that, the sample was taken out, cooled to remove the compression strain, and the thickness (d) after being left for 30 minutes was obtained. Calculated by: Unit% (mean value of n = 3).

(7) Foaming evaluation Five monitors were evaluated by applying detergent to the reticulated structure to see if it was easy to foam. The average score of the five monitors was used as the evaluation score.
3 points: Easy to foam and can be used in the same way as the current sponges scrubbing brush.
2 points: Easy to foam, but not unpleasant.
1 point: It is hard to foam and feels a little uncomfortable.
0 points ... No foaming.
When the average score was 2.5 points or more, it was marked as ⊚, when it was 2 points or more, it was rated as 〇, when it was 1.5 points or more, it was rated as Δ, and when it was less than 1.5 points, it was rated as ×. If the average score is 2 or more, there is no problem in practical use.

(8) Stain removal evaluation Five monitors were evaluated by washing the glass beaker and sink with detergent on the net-like structure. The average score of the five monitors was used as the evaluation score. The sensation when the reticulated structure was touched with bare hands was evaluated on the following four-point scale. The average score of the five monitors was used as the evaluation score.
3 points ... I feel that the dirt is removed more than the current sponges scrubbing brush.
2 points ... I feel that dirt can be removed without any problems.
1 point ... I feel that dirt is a little difficult to remove.
0 points ... I feel that it is difficult to remove dirt.
When the average score was 2.5 points or more, it was marked as ⊚, when it was 2 points or more, it was rated as 〇, when it was 1.5 points or more, it was rated as Δ, and when it was less than 1.5 points, it was rated as ×. If the average score is 2 or more, there is no problem in practical use.

(9) Evaluation of wash-off property of transfer stains After the test of (8) described above, the dirt adhering to the network structure was washed with running water, and the wash-out property of the transferred stains was evaluated. The average score of the five monitors was used as the evaluation score. The sensation when the reticulated structure was touched with bare hands was evaluated on the following four-point scale. The average score of the five monitors was used as the evaluation score.
3 points: I feel that the transfer stains are better washed away than the current sponge scrubbing brush.
2 points: I feel that the transfer stains are relatively better than the current sponge scrubbing brush.
1 point: I feel that it has the same washability of transfer stains as the current sponges scrubbing brush.
0 points: I feel that the transfer stains are less washable than the current sponge scrubbing brush.
When the average score was 2.5 points or more, it was marked as ⊚, when it was 2 points or more, it was rated as 〇, when it was 1.5 points or more, it was rated as Δ, and when it was less than 1.5 points, it was rated as ×. If the average score is 2 or more, there is no problem in practical use.

(10) Evaluation of drainage property The drainage property remaining in the network after draining the network structure after the test of (9) described above was evaluated. The average score of the five monitors was used as the evaluation score. The sensation when the reticulated structure was touched with bare hands was evaluated on the following four-point scale. The average score of the five monitors was used as the evaluation score.
3 points ... I feel that it has better draining properties than the current sponge scrubbing brush.
2 points ... I feel that it has a relatively better draining property than the current sponge scrubbing brush.
1 point ... I feel that it has the same draining property as the current sponges scrubbing brush.
0 points ... I feel that the draining property is worse than the current sponge scrubbing brush.
When the average score was 2.5 points or more, it was marked as ⊚, when it was 2 points or more, it was rated as 〇, when it was 1.5 points or more, it was rated as Δ, and when it was less than 1.5 points, it was rated as ×. If the average score is 2 or more, there is no problem in practical use.

(Thermoplastic resin used in Examples and Comparative Examples)
1) Polybutylene succinate high MFR product PTT MCC BIOCHANY LIMITED BioPBS ^TM FZ71 manufactured by LIMITED was used. The BioPBS ^TM FZ71 had a density of 1.26 g / cm ³ , an MFR of 22 g / 10 min, and a melting point of 115 ° C.
2) Polybutylene succinate low MFR product PTT MCC BIOCHEM COMPANY LIMITED BioPBS ^TM FZ91 manufactured by LIMITED was used. The BioPBS ^TM FZ91 had a density of 1.26 g / cm ³ , an MFR of 5 g / 10 min, and a melting point of 115 ° C.
3) Poly (butylene succinate / adipate)
BioPBS ^TM FD92 manufactured by PTT MCC BIOCHEM COMPANY LIMITED was used. The BioPBS ^TM FD92 had a density of 1.24 g / cm ³ , an MFR of 4 g / 10 min, and a melting point of 84 ° C.
4) Poly (butylene adipate / terephthalate)
Ecoflex (R) manufactured by BASF was used. This Ecoflex (R) had a density of 1.26 g / cm ³ , an MFR of 3 g / 10 min, and a melting point of 115 ° C.
5) Polylactic acid Luminy (R) L130 manufactured by Corbion was used. The Luminy (R) L130 had a density of 1.24 g / cm ³ , an MFR of 10 g / 10 min, and a melting point of 175 ° C.
6) Polyεcaprolactone Capa ^TM 6500 manufactured by Perstop was used. The Capa ^TM 6500 had a melting point of 58 ° C. The properties of each polymer and mixture are shown in Table 1.

[Example 1]
A nozzle having a round hole-shaped orifice with an outer diameter of 0.5 mm and a staggered arrangement with a hole pitch of 6 mm was used on the effective surface of the nozzle having a width of 96 mm in the width direction and a width of 31 mm in the thickness direction. Resin A was used in an absolutely dry state, and was discharged below the nozzle at a spinning temperature of 230 ° C. and a single-hole discharge rate of 1.0 g / min.
The water tank was adjusted to a position where the cooling water surface came 20 cm below the nozzle surface, and a pair of take-up conveyors were arranged in the water tank so as to partially protrude above the water surface.
The conveyor has a stainless steel endless net with a width of 20 cm, the width direction of the nozzle surface and the conveyor are arranged parallel to each other, the opening width of the endless net is 30 mm, and the aluminum plate is placed in the net direction to form the side surface. The side surface portion was formed by flowing water at a speed of 2.0 L / min.
By dropping the discharge line in the molten state on the aluminum plate that forms the opening, on the conveyor net, and the side surface of the conveyor net, a winding loop is formed, and the contact parts are fused. A three-dimensional network structure was formed.
While sandwiching both sides of the molten network structure with a take-up conveyor, it is drawn into cooling water at a speed of 0.96 m / min and solidified to flatten both sides in the thickness direction and the side surface direction, and then to a predetermined size. After cutting, it was dried and heat-treated with hot air at 80 ° C. for 20 minutes to obtain a network structure. The characteristics of the obtained network structure are shown in Table 2.

The obtained network structure is composed of a continuous linear body having a round cross section and a fiber diameter of 0.39 mm, an apparent density of 0.044 g / cm ³ , and a thickness with a flat surface. The width was 27.0 mm, the width was 80 mm, the D durometer hardness was 61, the MFR of the network structure was 24 g / 10 min, the melting point was 112.9 ° C., and the compression residual strain at 70 ° C. was 22.5%. The obtained net-like structure was excellent in foaming property, had an appropriate hardness, and was excellent in dirt removing property, transfer dirt washing property, draining property, and durability.

[Example 2]
A reticulated structure was obtained in the same manner as in Example 1 except that the resin B was adjusted to have a water content of 0.01% and the spinning temperature was 255 ° C. and the nozzle surface-cooling water distance was 30 cm.
The obtained network structure is composed of a continuous linear body having a round cross section and a fiber diameter of 0.69 mm, an apparent density of 0.050 g / cm ³ , and a thickness with a flat surface. The hardness was 29.4 mm, the D durometer hardness was 68, the MFR of the network structure was 8 g / 10 min, the melting point was 114.0 ° C., and the compression residual strain at 70 ° C. was 17.5%. The characteristics of the obtained network structure are shown in Table 2. The obtained net-like structure was excellent in foaming property, had an appropriate hardness, and was excellent in dirt removing property, transfer dirt washing property, draining property, and durability.

[Example 3]
Resin C was adjusted to a water content of 0.01% and used, and the spinning temperature was 260 ° C., the nozzle surface-cooling water distance was 25 cm, and the take-up speed was 0.76 m / min. Obtained a structure.
The obtained network structure is composed of a continuous linear body having a round cross section and a fiber diameter of 0.69 mm, an apparent density of 0.070 g / cm ³ , and a thickness with a flat surface. The hardness was 27.5 mm, the D durometer hardness was 58, the MFR of the network structure was 7 g / 10 min, the melting point was 87.5 ° C., and the compression residual strain at 70 ° C. was 20.4%. The characteristics of the obtained network structure are shown in Table 2.
The obtained net-like structure was excellent in foaming property, had an appropriate hardness, and was excellent in dirt removing property, transfer dirt washing property, draining property, and durability.

[Example 4]
Using resin D adjusted to a water content of 0.02%, the spinning temperature is 260 ° C, the single-hole discharge amount is 0.6 g / min, the nozzle surface-cooling water distance is 17 cm, and the take-up speed is 0.52 m / min. A network structure was obtained in the same manner as in Example 1 except for the above.
The obtained reticulated structure is composed of a continuous linear body having a round cross section and a fiber diameter of 0.57 mm, an apparent density of 0.061 g / cm ³ , and a thickness with a flat surface. The D durometer hardness was 49, the MFR of the network structure was 8 g / 10 min, the melting point was 116.8 ° C., and the compression residual strain at 70 ° C. was 19.3%. The characteristics of the obtained network structure are shown in Table 2.
The obtained net-like structure was excellent in foaming property, had an appropriate hardness, and was excellent in dirt removing property, transfer dirt washing property, draining property, and durability.

[Example 5]
Using a nozzle with an orifice outer diameter of 1.0 mm and a round hole-shaped orifice arranged in a staggered arrangement with a hole pitch of 8 mm, E was adjusted to a water content of 0.01% as a resin, the spinning temperature was 210 ° C, and the nozzle was used. A network structure was obtained in the same manner as in Example 1 except that the surface-cooling water distance was 22 cm and the take-up speed was 0.74 m / min.
The obtained network structure is composed of a continuous linear body having a round cross section and a fiber diameter of 0.59 mm, an apparent density of 0.040 g / cm ³ , and a thickness with a flat surface. The hardness was 59 at 29.3 mm, the D durometer hardness was 59, the MFR of the network structure was 28 g / 10 min, the melting point was 115.0 ° C., and the compression residual strain at 70 ° C. was 15.7%. The characteristics of the obtained network structure are shown in Table 2.
The obtained net-like structure was excellent in foaming property, had an appropriate hardness, and was excellent in dirt removing property, transfer dirt washing property, draining property, and durability.

[Example 6]
Three slits with an outer diameter of 3.6 mm, a slit width of 0.3 mm and a slit length of 1.8 mm were arranged at equal intervals from the center of the orifice on the effective surface of the nozzle with a width of 112 mm and a width of 43 mm in the thickness direction. A nozzle in which the three-leaf-shaped orifice was arranged in a staggered manner with a hole pitch of 8 mm was used. Resin D was used with the water content adjusted to 0.2%, the spinning temperature was 260 ° C., the single-hole discharge amount was 1.5 g / min, the nozzle surface-cooling water distance was 28 cm, and the take-up speed was 1.28 m / min. A network structure was obtained in the same manner as in Example 1 except for the above.
The obtained net-like structure has a Y cross section having a trilobal shape, an outer diameter of a fiber diameter of 0.8 mm, edges having three curvatures are evenly arranged, and the curvatures of the respective edges. It is composed of a continuous linear body with twice the radius of 0.3 mm, an apparent density of 0.060 g / cm ³ , a thickness of 30.2 mm when the surface is flattened, and a D durometer hardness of 38. The MFR of the reticulated structure was 40 g / 10 min, the melting point was 117.0 ° C., and the compression residual strain at 70 ° C. was 18.5%. The characteristics of the obtained network structure are shown in Table 2.
The obtained net-like structure was excellent in foaming property, had an appropriate hardness, and was excellent in dirt removing property, transfer dirt washing property, draining property, and durability.

[Example 7]
Example 6 except that the resin A was used in an absolutely dry state, the spinning temperature was 220 ° C., the discharge rate of a single hole was 1.4 g / min, the distance between the nozzle surface and the cooling water was 25 cm, and the take-up speed was 1.07 m / min. The obtained reticular structure obtained in the same manner as above has a Y cross section having a trilobal cross section, an outer diameter of fiber diameter of 1.0 mm, and edges having three curvatures. It is composed of continuous linear bodies that are evenly distributed and have a radius of curvature twice the radius of curvature of each edge of 0.4 mm, an apparent density of 0.049 g / cm ³ , and a thickness with a flat surface. The D durometer hardness was 65, the MFR of the network structure was 23 g / 10 min, the melting point was 113.6 ° C., and the compression residual strain at 70 ° C. was 19.6%. The characteristics of the obtained network structure are shown in Table 2.
The obtained net-like structure was excellent in foaming property, had an appropriate hardness, and was excellent in dirt removing property, transfer dirt washing property, draining property, and durability. It is considered that the reason why the stain removing property was the same as that of Example 1 was that the fiber diameter of Example 1 was equivalent to twice the radius of curvature of this example.

[Comparative Example 1]
A network structure was obtained in the same manner as in Example 1 except that the resin F was used in an absolutely dry state, the spinning temperature was 247 ° C, the nozzle surface-cooling water distance was 17 cm, and the take-up speed was 1.07 m / min. rice field.
The obtained reticulated structure has a round cross section, is composed of continuous linear bodies having a fiber diameter of 0.28 mm, is formed of streaks, has an apparent density of 0.050 g / cm ³ , and has a surface. The thickness in the flattened state was 28.1 mm, the D durometer hardness was 99, the MFR of the network structure was 12 g / 10 min, and the melting point was 171.0 ° C. The 70 ° C. compression residual strain could not be measured due to brittle fracture. The characteristics of the obtained network structure are shown in Table 2.
The obtained network structure was excellent in foaming property, washing property of transfer stains, and draining property. However, since the D-duro hardness was high and too hard, the brittle fracture was easily caused and the fiber was fractured from the gripped portion. As a result, it was inferior in dirt removal and durability.

[Comparative Example 2]
The same procedure as in Example 1 was carried out except that the spinning temperature was 210 ° C., the nozzle surface-cooling water distance was 22 cm, and the take-up speed was 0.44 m / min using the resin H.
However, the dice well directly under the nozzle was severe, and a good network structure could not be formed.

[Comparative Example 3]
It was carried out except that the resin G was used in an absolutely dry state, the spinning temperature was 210 ° C., the single-hole discharge amount was 0.5 g / min, the nozzle surface-cooling water distance was 17 cm, and the take-up speed was 0.54 m / min. A network structure was obtained in the same manner as in Example 1.
The obtained reticulated structure is composed of a continuous linear body having a round cross section and a fiber diameter of 0.47 mm, an apparent density of 0.048 g / cm ³ , and a thickness with a flat surface. The hardness was 29.9 mm, the hardness of the D durometer was 48, the MFR of the network structure was 62 g / 10 min, and the melting point was 58.0 ° C. The 70 ° C. compression residual strain could not be measured by melting. The characteristics of the obtained network structure are shown in Table 2.
The obtained network structure was excellent in foaming property, washing property of transfer stains, and draining property. However, it did not have an appropriate hardness and was inferior in stain removing property. Furthermore, when washed with hot water at about 40 ° C., it was easily deformed and was inferior in durability.

[Comparative Example 4]
Resin E was used in an absolutely dry state, the spinning temperature was 210 ° C., the nozzle surface-cooling water distance was 22 cm, and the take-up speed was 0.74 m / min. A reticular structure was obtained in the same manner as in Example 1 except that the reticular structure was naturally dried without being dried with hot air after being formed.
The obtained reticulated structure is composed of a continuous linear body having a round cross section and a fiber diameter of 0.59 mm, an apparent density of 0.040 g / cm ³ , and a thickness with a flat surface. The D durometer hardness was 53, the MFR of the network structure was 27 g / 10 min, the melting point was 114.0 ° C., and the compression residual strain at 70 ° C. was 39.0%. The characteristics of the obtained network structure are shown in Table 2.
The obtained net-like structure was excellent in foaming property, wash-out property of transfer stains, drainage property, moderate hardness and excellent dirt removal property, but was inferior in durability.

[Comparative Example 5]
Except for the fact that the resin D was used in an absolutely dry state, the spinning temperature was 260 ° C., the nozzle surface-cooling water distance was 30 cm, the take-up speed was 0.74 m / min, and after the network structure was formed, it was naturally dried without hot air drying. , A network structure was obtained in the same manner as in Example 1.
The obtained reticulated structure is composed of a continuous linear body having a round cross section and a fiber diameter of 0.90 mm, an apparent density of 0.041 g / cm ³ , and a thickness with a flat surface. The hardness was 29.3 mm, the D durometer hardness was 46, the MFR of the network structure was 4 g / 10 min, the melting point was 115.0 ° C., and the compression residual strain at 70 ° C. was 19.2%. The characteristics of the obtained network structure are shown in Table 2.
The obtained reticulated structure had an appropriate hardness and was excellent in stain removing property, washing property of transfer stains, draining property and durability, but was inferior in foaming property.

The network structure of the present invention is an environment-friendly network structure that has biodegradability, drainage property, resistance to settling, and convenience that transferred stains can be easily washed away. It is an improvement of the problems such as insufficient drainage, easy settling, transfer of dirt cannot be easily washed away, non-biodegradable and not environmentally friendly. It is a great contribution to the industry because it can provide a mesh structure suitable for daily sanitary goods such as brushes, drainers, cushioning materials, cushions, etc., which are relatively disposable.

Claims (6)

It is a network structure having a three-dimensional random loop joint structure composed of continuous linear bodies, having an apparent density of 0.005 g / cm ³ to 0.30 g / cm ³ , and a thickness of 10 mm to 100 mm. ,
The continuous striatum has a melting point of 80 to 180 ° C., an MFR of 6 to 60 g / 10 min, and is selected from polybutylene succinate, poly (butylene succinate / adipate), and poly (butylene adipate / terephthalate). , Containing at least one biodegradable thermoplastic resin (a),
The network structure is a network structure having a 70 ° C. compression residual strain of 35% or less. Polylactic acid, (polylactic acid / polybutylene succinate) block copolymer, polycaprolactone, poly (caprolactone / butylene succinate), poly (butylene succinate / carbonate), poly (ethylene terephthalate / succinate), poly (tetramethylene adipate) / Telephthalate), polyethylene succinate, polyvinyl alcohol, polyglycolic acid, which contains at least one biodegradable thermoplastic resin (c), and the biodegradable resin (a) and the biodegradable resin (a). The network structure according to claim 1, wherein the mixture of c) is contained in an amount of 80% by mass or more on a mass basis with respect to the thermoplastic resin composition. The network structure according to claim 1 or 2, wherein the continuous linear body has a circular cross-sectional shape and a fiber diameter of 0.1 mm to 0.8 mm. The continuous linear body has an irregular cross-sectional shape, has at least three or more equivalent curvatures on the outer peripheral portion, and has a fiber diameter or twice the radius of curvature thereof of 0.1 mm or more and 0.8 mm or less. Item 2. The reticulated structure according to Item 1 or 2. The reticulated structure according to claim 4, wherein the continuous linear body has a trilobal shape or a triangular cross-sectional shape. The network structure according to any one of claims 1 to 5, which is used for daily hygiene products and draining products.