Liner and pressure vessel
To provide a liner which contains a polyamide resin, wherein the polyamide resin contains a diamine-derived structural unit and a dicarboxylic acid-derived structural unit; 50 mol % or more of the diamine-derived structural unit is derived from a xylylenediamine; a content of a toughness improver in a region up to 30% in a thickness direction from one surface of the liner is from 5 to 20 mass %; and a content of the toughness improver in a region up to 30% in a thickness direction from the other surface of the liner is 0.5 mass % or less.
1. A liner comprising a polyamide resin, wherein
the polyamide resin contains a diamine-derived structural unit and a dicarboxylic acid-derived structural unit,
50 mol % or more of the diamine-derived structural unit is derived from a xylylenediamine,
a content of a toughness improver in a region up to 30% in a thickness direction from one surface of the liner is from 5 to 20 mass %, and
a content of the toughness improver in a region up to 30% in a thickness direction from the other surface of the liner is 0.5 mass % or less.
2. The liner according to claim 1 , wherein 50 mol % or more of the dicarboxylic acid-derived structural unit is derived from an α,ω-linear aliphatic dicarboxylic acid having from 4 to 20 carbons.
3. The liner according to claim 2 , wherein the toughness improver contains a carboxylic acid-modified polyolefin.
4. The liner according to claim 1 , wherein the toughness improver contains a carboxylic acid-modified polyolefin.
5. The liner according to claim 4 , wherein a carboxylic acid modification rate of the carboxylic acid-modified polyolefin is from 0.1 to 5.0 mass %.
6. A pressure vessel comprising the liner described in claim 1 and an outer layer of the liner.
7. The pressure vessel according to claim 6 , wherein the region of the liner in which the content of the toughness improver is from 5 to 20 mass % is provided at an inner side of the pressure vessel.
8. The pressure vessel according to claim 7 , wherein the region of the liner in which the content of the toughness improver is from 5 to 20 mass % is provided at an outer side of the pressure vessel.
9. The pressure vessel according to claim 7 , wherein the outer layer contains a fiber-reinforced plastic layer.
10. The pressure vessel according to claim 9 ,
wherein the region of the liner in which the content of the toughness improver is from 5 to 20 mass % is provided at an inner side of the pressure vessel;
the outer layer contains a fiber-reinforced plastic layer;
the fiber-reinforced plastic layer contains a thermosetting resin; and
the outer layer which is the fiber-reinforced plastic layer is adjacent to the region of the liner in which the content of the toughness improver is 0.5 mass % or less.
11. The pressure vessel according to claim 9 ,
wherein the region of the liner in which the content of the toughness improver is from 5 to 20 mass % is provided at an outer side of the pressure vessel;
the outer layer contains a fiber-reinforced plastic layer;
the fiber-reinforced plastic layer contains a thermosetting resin; and
the outer layer which is the fiber-reinforced plastic layer is adjacent to the region of the liner in which the content of the toughness improver is 0.5 mass % or less.
12. The pressure vessel according to claim 7 , which is for a hydrogen gas.
13. The pressure vessel according to claim 7 , which is for an oxygen gas.
14. The pressure vessel according to claim 6 , wherein the region of the liner in which the content of the toughness improver is from 5 to 20 mass % is provided at an outer side of the pressure vessel.
15. The pressure vessel according to claim 6 , wherein the outer layer contains a fiber-reinforced plastic layer.
16. The pressure vessel according to claim 15 , wherein the fiber-reinforced plastic layer contains a thermosetting resin.
17. The pressure vessel according to claim 15 , wherein the outer layer which is the fiber-reinforced plastic layer is adjacent to the region of the liner in which the content of the toughness improver is 0.5 mass % or less.
18. The pressure vessel according to claim 6 , which is for a hydrogen gas.
19. The pressure vessel according to claim 6 , which is for an oxygen gas.