Propylene-based resin foam particle and foam particle molded body

Patent metadata

Field	Value
Publication number	US-10385178-B2
Application number	US-201415111760-A
Country	US
Kind code	B2
Filing date	Dec 24, 2014
Priority date	Jan 17, 2014
Publication date	Aug 20, 2019
Grant date	Aug 20, 2019

Abstract

The present invention is concerned with expanded propylene resin beads including a core layer being in a foamed state and constituted of a propylene-based resin composition (a) and a cover layer constituted of an olefin-based resin (b), the propylene-based resin composition (a) satisfying the following (i) and (ii), and the olefin-based resin (b) satisfying the following (iii) or (iv).
(i) A mixture of 75% by weight to 98% by weight of a propylene-based resin (a1) having a melting point of 100° C. to 140° C. and 25% by weight to 2% by weight of a propylene-based resin (a2) having a melting point of 140° C. to 165° C. (ii) A difference between the melting point of the resin (a2) and the melting point of the resin (a1) is 15° C. or more. (iii) A crystalline olefin-based resin having a melting point TmB that is lower than a melting point TmA of the composition (a) and having a relation of 0° C.<[TmA−TmB]≤80° C. (iv) A non-crystalline olefin-based resin having a softening point TsB that is lower than TmA and having a relation of 0° C.<[TmA−TsB]≤100° C.

First claim

The invention claimed is:

1. Expanded propylene resin beads comprising a core layer being in a foamed state and comprising a propylene-based resin composition (a) and a cover layer comprising an olefin-based resin (b),
the propylene-based resin composition (a) satisfying the following (i) and (ii), and the olefin-based resin (b) satisfying the following (iii) or (iv):
(i) the propylene-based resin composition (a) is a mixture of 85% by weight to 98% by weight of a propylene-based resin (a1) having a melting point of 100° C. to 140° C. and 15% by weight to 2% by weight of a propylene-based resin (a2) having a melting point of 140° C. or more and less than 165° C., provided that a sum total of the propylene-based resin (a1) and the propylene-based resin (a2) is 100% by weight;
(ii) a difference between the melting point of the propylene-based resin (a2) and the melting point of the propylene-based resin (a1) [(melting point of a2)−(melting point of a1)] is 15° C. or more;
(iii) the olefin-based resin (b) is a crystalline olefin-based resin having a melting point (TmB) that is lower than a melting point (TmA) of the propylene-based resin composition (a), with a difference between the melting point (TmA) and the melting point (TmB) [TmA−TmB] being more than 0° C. and 80° C. or less; and
(iv) the olefin-based resin (b) is a non-crystalline olefin-based resin having a softening point (TsB) that is lower than the melting point (TmA) of the propylene-based resin composition (a), with a difference between the melting point (TmA) and the softening point (TsB) [TmA−TsB] being more than 0° C. and 100° C. or less,
wherein the propylene-based resin (a1) is a propylene-based random copolymer produced in the presence of a metallocene-based polymerization catalyst, and the propylene-based resin (a2) is a propylene-based copolymer and wherein a melt flow rate range for the propylene-based resin (a1) is from 1 to 100 g/10 min. and a melt flow range for the propylene-based resin (a2) is from 6 to 20 g/10 min.

2. The expanded propylene resin beads according to claim 1 , wherein in a first time DSC curve obtained by the heat flux differential scanning calorimetry when heated from ambient temperature to 200° C. at a heating rate of 2° C./min, the expanded propylene resin beads show a main endothermic peak in which a peak top temperature of the endothermic peak is 100° C. to 140° C. and one endothermic peak on the high temperature side of the main endothermic peak appears, and the main endothermic peak calorific value of 70% to 95% relative to a total endothermic peak calorific value.

3. The expanded propylene resin beads according to claim 1 , wherein in the item (ii), the difference in melting point between the propylene-based resin (a2) and the propylene-based resin (a1) [(melting point of a2)−(melting point of a1)] is 15 to 25° C.

4. The expanded propylene resin beads according to claim 1 , wherein the propylene-based resin (a1) and the propylene-based resin (a2) are a propylene-based resin produced in the presence of a metallocene-based polymerization catalyst.

5. The expanded propylene resin beads according to claim 1 , wherein the propylene-based resin composition (a) has a flexural modulus of 800 MPa to 1,200 MPa.

6. The expanded propylene resin beads according to claim 1 , wherein the propylene-based resin composition (a) has a content of the propylene-based resin (a1) of more than 90% by weight and 98% by weight or less and a content of the propylene-based resin (a2) of 2% by weight or more and less than 10% by weight.

7. The expanded propylene resin beads according to claim 1 , wherein the olefin-based resin (b) is a propylene-based resin produced in the presence of a metallocene-based polymerization catalyst.

8. The expanded propylene resin beads according to claim 1 , wherein the olefin-based resin (b) is an ethylene-based resin produced in the presence of a metallocene-based polymerization catalyst.

9. An expanded propylene resin beads molded article obtained through in-mold molding of the expanded propylene resin beads according to claim 1 .

10. The expanded propylene resin beads according to claim 1 , wherein the propylene-based resin (a1) has a melting point of 110° C. to 140° C.

11. The expanded propylene resin beads according to claim 1 , wherein the propylene-based resin (a1) has a melting point of 120° C. to 140° C.

12. The expanded propylene resin beads according to claim 1 , wherein the propylene-based resin (a1) has a melting point of 125° C. or more and less than 140° C.

13. The expanded propylene resin beads according to claim 1 , wherein the propylene-based resin (a1) has a melting point of 130° C. or more and less than 140° C.

14. The expanded propylene resin beads according to claim 1 , wherein the propylene-based resin (a1) has a melting point of 135° C. or more and less than 140° C.

15. The expanded propylene resin beads according to claim 1 , wherein the propylene-based resin (a2) has a melting point of 145° C. or more and less than 165° C.

16. The expanded propylene resin beads according to claim 1 , wherein the propylene-based resin (a2) has a melting point of 150° C. or more and less than 165° C.

17. The expanded propylene resin beads according to claim 1 , wherein the propylene-based resin (a2) has a melting point of 150° C. to 160° C.

18. The expanded propylene resin beads according to claim 1 , wherein the melt flow rate range for the propylene-based resin (a1) is from 2 to 8 g/10 min.

Assignees

• Jsp Corp

Inventors

• Ono Michitoshi
• Kitahara Taizo
• Tsurugai Kazuo

Classifications

• C08J2423/16

  Ethene-propene or ethene-propene-diene copolymers · CPC title

• C08J2323/16

  Ethene-propene or ethene-propene-diene copolymers · CPC title

• C08J2323/14

  Copolymers of propene (C08J2323/16 takes precedence) · CPC title

• C08J9/232

  by sintering expandable particles · CPC title

• C08J9/224

  Surface treatment · CPC title