Three-dimensional net-like structure
A three-dimensional net-like structure is provided that has a soft cushioning property and less variations of hardness and is less expensive. The three-dimensional net-like structure is made from a thermoplastic resin including a mixture of a polypropylene copolymer (a) and a polypropylene copolymer (b) and has a spring structure formed by bonding continuous filaments partly in random in loops. The polypropylene copolymer (a) has a flexural modulus that is different from a flexural modulus of the polypropylene copolymer (b).
1. A three-dimensional net-like structure that is made from a thermoplastic resin comprising a mixture of a polypropylene copolymer (a) and a polypropylene copolymer (b), wherein:
the three-dimensional net-like structure has a spring structure formed by bonding continuous filaments partly at random in loops,
the polypropylene copolymer (a) has a flexural modulus that is different from a flexural modulus of the polypropylene copolymer (b),
the flexural modulus of the polypropylene copolymer (a) is 100 to 1600 MPa and the flexural modulus of the polypropylene copolymer (b) is 5 to 100 MPa, and
the thermoplastic resin includes 10 to 40% by weight of the polypropylene copolymer (a) and 60 to 90% by weight of the polypropylene copolymer (b).
2. The three-dimensional net-like structure according to claim 1 ,
wherein the polypropylene copolymer (a) has a MFR of 5 to 35 g/10 min and the polypropylene copolymer (b) has a MFR of 4 to 30 g/10 min.
3. The three-dimensional net-like structure according claim 1 ,
wherein the three-dimensional net-like structure is used for cushions, vehicle seats, ship seats, train seats, Japanese floor cushions, pillows, nursing care products, or cushions or mattress for beds.
4. The three-dimensional net-like structure according to claim 1 ,
wherein the polypropylene copolymer (a) is a propylene-(α-olefin) copolymer and has an α-olefin content of 3 to 30% by weight.
5. The three-dimensional net-like structure according to claim 1 ,
wherein the polypropylene copolymer (b) is a propylene-(α-olefin) copolymer and has an α-olefin content of 10 to 49% by weight.
6. A three-dimensional net-like structure that is made from a thermoplastic resin comprising a mixture of a polypropylene copolymer (a) and a polypropylene copolymer (b), wherein:
the three-dimensional net-like structure has a spring structure formed by bonding continuous filaments partly at random in loops,
the polypropylene copolymer (a) has a flexural modulus that is different from a flexural modulus of the polypropylene copolymer (b), and
the three-dimensional net-like structure has a hysteresis loss of 5 to 60%.
7. A three-dimensional net-like structure that is made from a thermoplastic resin comprising a mixture of a polypropylene copolymer (a) and a polypropylene copolymer (b), wherein:
the three-dimensional net-like structure has a spring structure formed by bonding continuous filaments partly at random in loops,
the polypropylene copolymer (a) has a flexural modulus that is different from a flexural modulus of the polypropylene copolymer (b), and
the three-dimensional net-like structure has a longitudinal direction corresponding to an extrusion direction, a lateral direction and a thickness direction perpendicular to the extrusion direction and has a thermal expansion rates of 0 to 8% in the longitudinal direction and in the lateral direction before and after a hot-air drying test that is performed at a temperature of 110° C. for 30 minutes.