Flame-retardant resin composition, insulated electric wire, and wire harness

Patent metadata

Field	Value
Publication number	US-2024270955-A1
Application number	US-202118023847-A
Country	US
Kind code	A1
Filing date	Aug 2, 2021
Priority date	Sep 3, 2020
Publication date	Aug 15, 2024
Grant date	—

Abstract

Provided is a silane-crosslinkable polyolefin-based flame-retardant resin composition having high flexibility and high handleability, and an insulated electric wire and a wire harness obtained using the flame-retardant resin composition. The flame-retardant resin composition includes, as resin components: a silane-grafted polyolefin (A) obtained by grafting a silane coupling agent onto a polyolefin; an unmodified polyolefin (B); and a modified polyolefin (C) having one or more functional groups selected from a carboxyl group, an ester group, an acid anhydride group, an amino group, and an epoxy group. The resin composition further includes a flame retardant (D) and a crosslinking catalyst (E). A crosslinked product obtained by subjecting the flame-retardant resin composition to silane crosslinking has a melting point of 80° C. or higher and a flexural modulus of 100 MPa or less.

First claim

Listings of claims:

1 . A flame-retardant resin composition comprising, as resin components:
a silane-grafted polyolefin (A) obtained by grafting a silane coupling agent onto at least one polyolefin; an unmodified polyolefin (B); and a modified polyolefin (C) having one or more functional groups selected from a carboxyl group, an ester group, an acid anhydride group, an amino group, and an epoxy group, the flame-retardant resin composition further comprising: a flame retardant (D); and a crosslinking catalyst (E), wherein a crosslinked product obtained by subjecting the flame-retardant resin composition to silane crosslinking has a melting point of 80° C. or higher and a flexural modulus of less than 80 MPa.

2 . The flame-retardant resin composition according to claim 1 ,
wherein the at least one polyolefin constituting the silane-grafted polyolefin (A) includes:
a first polyolefin (a-1); and
a second polyolefin (a-2), and
the first polyolefin (a-1) has a higher melting point than the second polyolefin (a-2).

3 . The flame-retardant resin composition according to claim 2 ,
wherein the first polyolefin (a-1) has a density of 0.870 g/cm 3 or less, a melting point of 110° C. or higher, and a flexural modulus of 11 MPa or less, the second polyolefin (a-2) has a density of 0.870 g/cm 3 or less, a melting point of 60° C. or lower, and a flexural modulus of 11 MPa or less, and the first polyolefin (a-1) and the second polyolefin (a-2) are mixed at a mass ratio (a-1)/(a-2) within a range of 30/70 or more and 70/30 or less.

4 . A flame-retardant resin composition comprising, as resin components:
a silane-grafted polyolefin (A) obtained by grafting a silane coupling agent onto at least one polyolefin; an unmodified polyolefin (B); and a modified polyolefin (C) having one or more functional groups selected from a carboxyl group, an ester group, an acid anhydride group, an amino group, and an epoxy group, the flame-retardant resin composition further comprising: a flame retardant (D); and a crosslinking catalyst (E), wherein the at least one polyolefin constituting the silane-grafted polyolefin (A) includes:
a first polyolefin (a-1) having a density of 0.870 g/cm 3 or less, a melting point of 110° C. or higher, and a flexural modulus of 11 MPa or less; and
a second polyolefin (a-2) having a density of 0.870 g/cm 3 or less, a melting point of 60° C. or lower, and a flexural modulus of 11 MPa or less, and
the first polyolefin (a-1) and the second polyolefin (a-2) are mixed at a mass ratio (a-1)/(a-2) within a range of 30/70 or more and 70/30 or less.

5 . The flame-retardant resin composition according to claim 1 ,
wherein the unmodified polyolefin (B) has a density of 0.950 g/cm 3 or less and a flexural modulus of 200 MPa or less.

6 . The flame-retardant resin composition according to claim 1 , comprising, as the resin components:
10 parts by mass or more and 70 parts by mass or less of the silane-grafted polyolefin (A); 20 parts by mass or more and 60 parts by mass or less of the unmodified polyolefin (B); and 1 part by mass or more and 30 parts by mass or less of the modified polyolefin (C).

7 . The flame-retardant resin composition according to claim 1 , comprising at least one of magnesium hydroxide and aluminum hydroxide as the flame retardant (D) in a total amount of 30 parts by mass or more and 150 parts by mass or less with respect to 100 parts by mass of the resin components.

8 . The flame-retardant resin composition according to claim 7 ,
wherein the magnesium hydroxide and the aluminum hydroxide have an average particle size of 0.5 μm or more and 5.0 μm or less.

9 . The flame-retardant resin composition according to claim 1 ,
wherein the crosslinking catalyst (E) is contained in an amount of 0.1 parts by mass or more and 1 part by mass or less with respect to 100 parts by mass of the resin components.

10 . The flame-retardant resin composition according to claim 1 , further comprising at least one of:
a hindered phenol-based antioxidant (F); a metal oxide (G); a sulfur-based antioxidant (H); and a lubricant (I).

11 . The flame-retardant resin composition according to claim 10 ,
wherein the sulfur-based antioxidant (H) includes at least one imidazole-based compound.

12 . The flame-retardant resin composition according to claim 10 ,
wherein the components (F) to (I) are contained in the following amounts with respect to 100 parts by mass of the resin components: 0.5 parts by mass or more and 20 parts by mass or less of the hindered phenol-based antioxidant (F); 0.5 parts by mass or more and 15 parts by mass or less of the metal oxide (G); 0.5 parts by mass or more and 20 parts by mass or less of the sulfur-based antioxidant (H); and 0.1 parts by mass or more and 5 parts by mass or less of the lubricant (I).

13 . An insulated electric wire comprising:
a conductor; and an electric wire coating material constituted by a crosslinked product of the flame-retardant resin composition according to claim 1 and covering an outer circumference of the conductor.

14 . A wire harness comprising the insulated electric wire according to claim 13 .

Assignees

• Autonetworks Technologies Ltd
• Sumitomo Wiring Systems
• Sumitomo Electric Industries

Inventors

• Hase Tatsuya
• Shimada Tatsuya

Classifications

• H01B3/441 Primary

  from alkenes · CPC title

• C08L2207/062

  HDPE · CPC title

• C08L2205/035

  containing four or more polymers in a blend · CPC title

• C08L2205/025

  containing two or more polymers of the same hierarchy C08L, and differing only in parameters such as density, comonomer content, molecular weight, structure · CPC title

• C08L2201/02

  Flame or fire retardant/resistant · CPC title