초록 ▼

A multilayered film exhibiting good transparency, welding resistance, puncture resistance and impact strength having an outer layer selected from the group consisting of: (1) homopolymers of polypropylene, (2) ethylene/propylene copolymers and (3) blends of (a) high density polyethylene and (b) prop

A multilayered film exhibiting good transparency, welding resistance, puncture resistance and impact strength having an outer layer selected from the group consisting of: (1) homopolymers of polypropylene, (2) ethylene/propylene copolymers and (3) blends of (a) high density polyethylene and (b) propylene and ethylene block copolymers; an inner layer of a different composition from the outer layer and selected from the group consisting of ethylene and α-olefin copolymers, and ethylene and α-olefin copolymers blended with low density polyethylene; and a complex intermediate layer joining the outer layer to the inner layer, the complex intermediate layer having a plurality of sublayers defining an upper nucleus B1, a core B2 and a lower nucleus B3, the upper nucleus being a propylene and ethylene copolymer and the lower nucleus being an ethylene copolymer with an ethylene content greater than the upper nucleus.

대표청구항 ▼

A multilayered film exhibiting good transparency, welding resistance, puncture resistance and impact strength having an outer layer selected from the group consisting of: (1) homopolymers of polypropylene, (2) ethylene/propylene copolymers and (3) blends of (a) high density polyethylene and (b) prop

A multilayered film exhibiting good transparency, welding resistance, puncture resistance and impact strength having an outer layer selected from the group consisting of: (1) homopolymers of polypropylene, (2) ethylene/propylene copolymers and (3) blends of (a) high density polyethylene and (b) propylene and ethylene block copolymers; an inner layer of a different composition from the outer layer and selected from the group consisting of ethylene and α-olefin copolymers, and ethylene and α-olefin copolymers blended with low density polyethylene; and a complex intermediate layer joining the outer layer to the inner layer, the complex intermediate layer having a plurality of sublayers defining an upper nucleus B1, a core B2 and a lower nucleus B3, the upper nucleus being a propylene and ethylene copolymer and the lower nucleus being an ethylene copolymer with an ethylene content greater than the upper nucleus. er dispersed in resin on a carbon substrate, and heating the slurry at a temperature of not less than 1500° C. and under a pressure of not more than 10 Torr, thereby forming a silicon carbide containing carbon layer having a thickness of not less than 1 mm and dispersed generally uniformly along a depth direction from a surface of said substrate. 12. The method according to claim 11, wherein the resin is selected from the group consisting of polyamide-imide resin, polyvinyl alcohol resin, and polyamide resin. 13. The method according to claim 11, wherein the carbon substrate is a graphite substrate. 14. The method according to claim 13, wherein the graphite substrate is an isotropic graphite. 15. The method according to claim 13, wherein the graphite substrate has a bulk density of not less than 1.70 (g/cm3), a mean pore radius of not more than 2.5 (μm), a bending strength of not less than 300 (kgf/cm2) and thermal conductivity of not less than 50 (kcal/hrm° C.). 16. The method according to claim 13, wherein the graphite substrate has a bulk density of not less than 1.77 (g/cm3), a mean pore radius of not more than 1.5 (μm) and a bending strength of not less than 450 (kgf/cm2). 17. The method according to claim 13, wherein the graphite substrate has a bulk density of not less than 1.80 (g/cm3), a mean pore radius of not more than 1.2 (μm) and a bending strength of not less than 700 (kgf/cm2). 18. The method according to claim 13, wherein the graphite substrate and the silicon carbide containing carbon layer are impregnated with metal or resin. 19. The method according to claim 13, wherein the silicon carbide containing carbon layer is formed on the entire surface of the graphite substrate and has a gas permeability of 10-5to 10-6cm2/s.