JPH0760861A - Three-dimensional network structure - Google Patents

Abstract

PURPOSE:To retain compression properties, improve workability in the field and lighten the weight of filaments by forming the filaments having a specified outer periphery diamer and a specified hollow rate into a continuous and/or discontinuous hollow shape. CONSTITUTION:Loops are formed with a number of filaments made of a thermoplastic resin, and the loops are mutually adhered at points. Each filament has 0.1 to 7mm of an outer periphery diameter and 5 to 80% of a hollow rate and is formed into a continuous and/or discontinuous hollows shape. A polyolefin polymer, a polyester polymer, a polyester elastomer and the like such as polyethylene, polypropylene, etc., are used as a thermoplastic resin. When the outer periphery diameter of the filament exceeds 7mm, the weight of the filaments is increased, and workability in the field also becomes worse. On the other hand, the hollow rate less than 5% has little effect to lighten the weight of the same and, when it exceeds 80%, a compression strength is reduced. The resin is spun from a nozzle of an extruder to be dropped under its own weight. While the filaments are in a molten state, they are allowed to adhere to one another and cured, whereby compression properties are made better.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention is a lightweight three-dimensional net-like structure, and is used for drainage materials of soft ground and liquefied ground, civil engineering materials such as embankment reinforcement materials, bedding, furniture, vehicles, etc. The present invention relates to a three-dimensional net body that can be used as a cushion material.

[0002]

2. Description of the Related Art Many three-dimensional network structures using a thermoplastic resin have been proposed. For example, there is a method in which when a filament in a molten state is naturally dropped from a nozzle, the filament is taken at a speed slower than that speed and then rapidly cooled and solidified.
The diameter of these filaments and the number of filaments are determined for the purpose of obtaining filaments that take into consideration the compression characteristics suitable for each application, and in order to obtain high compressive strength, they become thick filaments and the weight increases. .

[0003]

However, in these three-dimensional network structures, it is possible to reduce the weight by reducing the diameter of the filaments or reducing the number of filaments, but at the same time the compression characteristics deteriorate. . In view of this, the present invention provides a three-dimensional reticulated structure that retains compression characteristics, improves workability on site, and is lightweight. Further, since the amount of resin used is reduced due to the weight reduction, it is possible to provide a product with a reduced cost.

[0004]

The present invention is a net-like structure comprising a large number of thermoplastic resin filaments forming a loop, and the loops being point-bonded to each other. A three-dimensional network structure having an outer peripheral diameter of 0.1 to 7 mm and a hollow ratio of 5 to 80%, and having a continuous and / or discontinuous hollow shape.

The present invention will be described in detail below. As the thermoplastic resin according to the present invention, polyolefin-based polymers such as polyethylene and polypropylene, polyester-based polymers, polyester elastomers and polyurethane-based polymers are used.

The olefin resin is preferably a homopolymer or copolymer selected from polyolefins such as polyethylene and polypropylene, and these may be used as a mixture of two or more kinds of polymers.

The polyester polymer mainly comprises terephthalic acid as a main acid component and at least one glycol, preferably a polyester having a glycol component of at least one alkylene glycol selected from ethylene glycol, trimethylene glycol and tetramethylene glycol. set to target. Further, it may be a polyester in which a part of the terephthalic acid component is replaced with another difunctional carboxylic acid component, and / or a part of the glycol component is replaced with the above glycol or other diol component other than the main component. It may be polyester. Examples of the bifunctional carboxylic acid other than terephthalic acid used here include isophthalic acid, naphthalene dicarboxylic acid, diphenylcarboxylic acid diphenoxyethanedicarboxylic acid, β-hydroxyethoxybenzoic acid, p-oxybenzoic acid, adipic acid, sebacine. Examples thereof include acids and aromatic, aliphatic and alicyclic bifunctional carboxylic acids of 1,4-cyclohexanedicarboxylic acid. A homopolymer or a copolymer selected from these is preferable,
Moreover, you may use these, mixing 2 or more types of polymers.

Examples of polyester elastomers include polyester-polyether block copolymers and polyester type block copolymers. The polyester-polyether block copolymer, the hard segment of the polyester, the soft segment of the polyether, by the two are alternately arranged,
It is a block copolymer having the properties of a rubber-like elastic material.
The acid and alcohol constituting such a polyester unit are mainly an aromatic dicarboxylic acid and an alkylene glycol having 2 to 15 carbon atoms, respectively. Specific examples of the dicarboxylic acid include terephthalic acid and ethylene bis (p
-Oxybenzoic acid), naphthalenedicarboxylic acid, adipic acid, sebacic acid, 1,4-cyclohexanedicarboxylic acid, p- (β-didroxyethoxy) benzoic acid and the like. Specific examples of the alcohol include ethylene glycol, propylene glycol, tetramethylene glycol, pentamethylene glycol, 2,2-dimethyltrimethylene glycol, hexamethylene glycol, decamethylene glycol, cyclohexanedimethanol, cyclohexanediethanol, benzenedimethanol, benzenediethanol. Etc.

As the above-mentioned acid and alcohol, those having a melting point of 150 ° C. or higher when a polyester having a molecular weight of a degree capable of forming a fiber is used are suitable. The polyether unit, which is the soft segment of the block copolymer, is a polyoxyalkylene glycol having an average molecular weight of about 500 to 5,000. This polyoxyalkylene glycol unit has an oxyalkylene group whose alkylene group has 2 to 9 carbon atoms as a monomer unit. Specifically, poly (oxyethylene) glycol, poly (oxypropylene) glycol, poly (oxytetramethylene) glycol and the like are mentioned as suitable examples. The polyether may be a homopolymer, a random copolymer, a block copolymer, or a mixture of two or more kinds of polyether. Further, the polyether may have a small amount of an aliphatic group, an aromatic group or the like in the molecular chain. Further, a modified polyether having sulfur, nitrogen, phosphorus or the like may be used.
The polyester-polyether block copolymer has a polyether unit content of 1 to 85% by weight, preferably 5 to 80%.
% By weight and 99 to 15 polyester units
It is contained in a weight ratio of 95 to 20% by weight.

Examples of the polyester type block copolymer include those obtained by reacting a crystalline aromatic polyester with lactones. As the crystalline aromatic polyester, a polymer mainly having an ester bond or an ester bond and an ether bond, having at least one kind of aromatic group as a main repeating unit, and having a hydroxyl group at a molecular end is mentioned. . The crystalline aromatic polyester preferably has a melting point of 150 ° C. or higher when a polymer having a high degree of polymerization is formed. When used as the cushioning material of the present invention, a polymer having a molecular weight of 5000 or more is preferable. Suitable specific examples of the crystalline aromatic polyester can find homopolyester, polyester ether, copolyester, copolyester ether and the like. Examples of homopolyesters include polyethylene terephthalate,
Examples thereof include polytetramethylene terephthalate, poly-1,4-cyclohexylene dimethylene terephthalate, and polyethylene-2,6-naphthalate. Examples of polyester ethers include polyethyleneoxy benzoate, poly-p-phenylene bisoxyethoxy terephthalate, and the like.

Examples of the copolymerized polyester or the copolymerized polyester ether include a polymer mainly containing a tetramethylene terephthalate unit or an ethylene terephthalate unit and further containing another copolymerization component. Such copolymerization components include tetramethylene terephthalate units, ethylene isophthalate units, tetramethylene adipate units, ethylene adipate units,
Examples thereof include a tetramethylene sebacate unit, an ethylene sebacate unit, a 1,4-cyclohexylene dimethylene terephthalate unit, a tetramethylene-p-oxybenzoate unit and an ethylene-p-oxybenzoate unit. The copolyester and the copolyester ether preferably contain 60 mol% or more of a tetramethylene terephthalate unit or an ethylene terephthalate unit.

As the other constituent lactone which forms the polyester type block copolymer, ε-caprolactone is most preferable, but enanthlactone, caprylolactin and the like are also used. 2 of these lactones
You may use 1 or more types. The polyester type block copolymer is obtained by copolymerizing the above crystalline aromatic polyester and lactone in a weight ratio of 97/3 to 5/95. This weight ratio is preferably 95/5 to 30/70. In the above copolymerization, a catalyst is added if necessary, and the mixture is heated and mixed to carry out the reaction. The polyester elastomer thus obtained (polyester-
The polyether block copolymer and / or the polyester type block copolymer) may be used alone or in combination of two or more kinds. Further, two or more kinds of the polyester polymer and the polyester elastomer may be mixed and used.

Next, as the polyurethane polymer used in the present invention, (A) a polymer having a terminal hydroxyl group having a number average molecular weight of 1000 to 6000 in the presence or absence of a usual solvent (dimethylformamide, dimethylacetamide, etc.). Ether and / or polyester,
(B) A polyisocyanate containing an organic diisocyanate as a main component is reacted to first produce a prepolymer having isocyanate groups at both ends (a reaction accelerator, a catalyst, and a reaction inhibitor can be used if necessary). A typical example is a method in which the same applies to the latter-stage reaction), and then in the liquid state, the chain is extended with a polyamine containing (C) a diamine as a main component. In the above method, each component may be added to the system at a time for reaction, or each component may be divided and reacted in multiple stages. Further, an end-terminating agent such as monoamine may be added and reacted in the middle or end of the reaction. As the polyester (A) and polyethers, conventionally known polytetramethylene glycol, polybutylene adipate copolyester, etc. can be used, and those having a number average molecular weight of 1,000 to 6000 are preferable,
More preferably, some are 1300 to 5,000.
As the polyisocyanate of (B), conventionally known polyisocyanates can be used, but an isocyanate such as diphenylmethane-4,4′-diisocyanate is mainly used, and if necessary, a conventionally known triisocyanate and the like can be used in a trace amount. You may add and use. As the polyamine (C), known diamines such as ethylenediamine and 1,2-propylenediamine are mainly used, and if necessary, trace amounts of triamine and tetramine may be used in combination.
You may use these urethane type polymers individually or in mixture of 2 or more types. These polymers have rigidity and have excellent compression characteristics after being cooled and solidified in the form of filaments.

The outer diameter of the filament is preferably in the range of 0.1 to 7 mm, and if it is less than 0.1 mm, the resulting three-dimensional network structure lacks in compressive strength. On the other hand, if the outer diameter exceeds 7 mm, the compression characteristics are sufficiently satisfied, but the weight of the three-dimensional network structure increases, and the productivity and workability on site deteriorate.

The inside of the filament has a hollow rate of 5 to 80%, preferably 10 to 60%, and more preferably 10 to 55%, which is a continuous and / or discontinuous hollow shape. The effect is small, and when the hollow ratio exceeds 80%, the resin portion of the obtained filaments becomes thin and the compressive strength of each filament decreases, and the three-dimensional reticulated structure composed of these has satisfactory compression characteristics. I can't. Techniques for hollowing the yarn are generally, but not limited to, a method of extruding the filament from a C-shaped nozzle and a method of utilizing air pressure.

In order to form a three-dimensional network structure, the resin is melted by an extruder, a large number of filaments are spun from a nozzle and spontaneously dropped, and the filaments are melt-bonded and solidified while still in a molten state. A three-dimensional network structure having more excellent compression properties can be obtained. When the three-dimensional net structure is used for soft ground, drainage base material of liquefied ground, civil engineering materials such as embankment reinforcement, bedding, furniture, vehicles, etc., balance by setting the porosity within the range of 80 to 97%. A solid three-dimensional network structure can be obtained. Further, a fiber reinforcing material, a filler, a colorant, a stabilizer, a crystallization accelerator, and other respective agents may be appropriately blended to the extent that the properties of the three-dimensional network structure are not impaired.

[0017]

In the present invention, the three-dimensional network structure has a continuous and / or discontinuous hollow shape having a hollow ratio of 5 to 80% so that the compressive strength of each wire is sufficiently maintained, and these wires are mutually resistant. The three-dimensional network structure having a large number of melt-bonded points and composed of a plurality of filaments has excellent strength, strain, and recovery characteristics upon compression, and a lightweight three-dimensional network structure can be obtained.

[0018]

The present invention will be described in detail below by way of examples, but the present invention is not limited thereto. The methods for measuring various physical properties are as follows. Weight Weight of 1 m ^{2 of} sample Compressive strength Measured according to JIS K7208-1975, and compressive strength is determined by the value when the strain rate is 20%. Compressive residual strain rate When the compressive strength of the three-dimensional network structure was measured, a load was applied until the strain amount became 1/2 of the thickness of the first sample, and then the load was removed 5 times, and then 3 hours later. The thickness of the sample is measured, and the compression residual strain rate is calculated by the following formula.
Compressive residual strain rate = thickness of sample after test (mm) / thickness of first sample (mm)

The three-dimensional network structure was prepared according to the following formulation. With a single screw extruder with a screw diameter of 50 mm, the cylinder temperature was set to 240 ° C, and an outside diameter of 1.2 mm and an inside diameter of 0.85 mm were divided into 120 °. Become 50
Spinning out from a nozzle group of holes at a discharge rate of 15 kg per hour, cooling water is placed 20 cm below the nozzle surface, and a pair of take-up conveyors are installed in the cooling water, which is 0.5 m / min. It is drawn into water at a speed to obtain a three-dimensional net-like structure having a thickness of 3 cm and a width of 20 cm.

[0020]

【Example】

Example 1 A three-dimensional network structure was prepared under the above-mentioned production conditions using polypropylene having a melt index of 8Og / 10 min at 230 ° C. Table 1 shows the results of measuring the weight and compression characteristics of the obtained three-dimensional network structure. Example 2 A three-dimensional network structure was prepared in the same manner as in Example 2 using polypropylene having a melt index at 230 ° C. of 30 g / 10 min. The results are shown in Table 1. Comparative Example 1 Instead of the hollow nozzle, a nozzle 5 having a hole outer diameter of 1.2 mm
The melt index at 230 ° C. was 8 g / same as in Example 1 except that spinning was performed from a 0-hole nozzle group at 30 kg / hr.
A three-dimensional network structure was created using polypropylene for 10 minutes. The results are shown in Table 1. Comparative Example 2 A three-dimensional network structure was prepared in the same manner as in Comparative Example 1 using polypropylene having a melt index of 230 g at 30 g / 10 min. The results are shown in Table 1.

[0021]

[Table 1]

As shown in Table 1, the obtained three-dimensional network structure had almost the same compressive strength due to the reduction in weight by about half, and the compressive residual strain rate was also almost the same value, and was excellent in recoverability.

[0023]

EFFECTS OF THE INVENTION The hollow three-dimensional network structure of the present invention has the above-mentioned structure. Even though it is lightweight, it has about the same compressive strength as a solid one, and has a residual compression strain ratio. Since it is also light and hard to settle, it is suitable for soft ground, drainage base material of liquefied ground, civil engineering materials such as embankment reinforcement, bedding, furniture, cushion materials used for vehicles, etc. It can also be useful for improving the efficiency and efficiency of transportation, delivery, and workability on site.

Claims (1)

[Claims] 1. A net-like structure in which a large number of thermoplastic resin filaments form a loop and the loops are point-bonded to each other, and the filament has an outer diameter of 0.1 to 7 mm. The hollow structure has a hollow ratio of 5 to 80% and has a continuous and / or discontinuous hollow shape.