Modified propylene-(α-olefin) copolymer, method for producing same, coating material comprising same, resin composition for molding use, and hot-melt composition

1. A modified propylene-α-olefin copolymer (A) having an acid value of 0.5 to 100 KOHmg/g obtained by grafting at least one selected from unsaturated carboxylic acids and derivatives thereof and unsaturated sulfonic acids and salts thereof onto a propylene-α-olefin copolymer (A1),

wherein the propylene-α-olefin copolymer (A1) contains 60 to 95 mol % of a propylene-derived constitutional unit (a) and 5 to 40 mol % of a C 4+ α-olefin-derived constitutional unit (b), a total amount of the constitutional unit (a) and the constitutional unit (b) being 100 mol %, and the propylene-α-olefin copolymer (A1) satisfies all of requirements below (i) to (iv):

(i) a weight average molecular weight (Mw) measured by GPC of 3,000 to 40,000;

(ii) a melting point (Tm) measured by DSC of 60 to 110° C.;

(iii) a half width of a crystalline melting point peak measured by the DSC of 1 to 20° C.; and

(iv) a number of vinylidene groups per 1,000 carbon atoms measured by 1 H-NMIR of 0.5 to 5; and

wherein a crystallization temperature ratio Tc(A1)/Tc(A) is 1.0 to 1.6, the Tc(A) being a crystallization temperature (° C.) of the modified propylene-α-olefin copolymer (A) and the Tc(A1) being a crystallization temperature (° C.) of the propylene-α-olefin copolymer (A1).

2. The modified propylene-α-olefin copolymer (A) according to claim 1 , wherein the propylene-α-olefin copolymer (A1) is obtained by thermally decomposing a propylene-C 4+ α-olefin copolymer (A2).

3. The modified propylene-α-olefin copolymer (A) according to claim 2 , wherein the propylene-C 4+ α-olefin copolymer (A2) contains 60 to 95 mol % of a propylene-derived constitutional unit (a′) and 5 to 40 mol % of a C 4+ α-olefin-derived constitutional unit (b′), wherein a total amount of the constitutional unit (a′) and the constitutional unit (b′) is 100 mol %, and satisfies all of requirements below (i′) to (iii′):

(i′) a weight average molecular weight (Mw) measured by the GPC of 50,000 to 1,000,000;

(ii′) a melting point (Tm) measured by the DSC of 60 to 120° C.; and

(iii′) a half width of a crystalline melting point peak measured by the DSC of 1 to 20° C.

4. The modified propylene-α-olefin copolymer (A) according to claim 1 , wherein the propylene-α-olefin copolymer (A1) further satisfies requirement below (v):

(v) a ΔH of a melting peak measured by the DSC of 40 to 100 J/g.

5. A method for producing a modified propylene-α-olefin copolymer (A) comprising:

thermally decomposing a propylene-C4+ α-olefin copolymer (A2) to obtain a propylene-α-olefin copolymer (A1) containing 60 to 95 mol % of a propylene-derived constitutional unit (a) and 5 to 40 mol % of a C4+ α-olefin-derived constitutional unit (b), wherein a total amount of the constitutional unit (a) and the constitutional unit (b) is 100 mol %, and satisfying all of requirements below (i) to (iv):

(i) a weight average molecular weight (mw) measured by GPC of 3,000 to 40,000;

(ii) a melting point (Tm) measured by DSC of 60 to 110° C.;

(iii) a half width of a crystalline melting point peak measured by the DSC of 1 to 20° C.; and

(iv) a number of vinylidene groups per 1,000 carbon atoms measured by 1 H-NMR of 0.5 to 5; and

graft polymerizing at least one selected from unsaturated carboxylic acids and derivatives thereof and unsaturated sulfonic acids and salts thereof onto the propylene-α-olefin copolymer (A1) to obtain a modified propylene-α-olefin copolymer (A) having an acid value of 0.5 to 100 KOHmg/g, and

wherein a crystallization temperature ratio Tc(A1)/Tc(A) is 1.0 to 1.6, Tc(A) being a crystallization temperature (° C.) of the modified propylene-α-olefin copolymer (A) and Tc(A1) being a crystallization temperature (° C.) of the propylene-α-olefin copolymer (A1).

6. The method for producing a modified propylene-α-olefin copolymer (A) according to claim 5 , wherein the propylene-α-olefin copolymer (A1) is obtained by thermally decomposing the propylene-C 4+ α-olefin copolymer (A2) at 300 to 450° C. for 5 minutes to 10 hours.

7. The method for producing a modified propylene-α-olefin copolymer (A) according to claim 5 , wherein the propylene-C 4+ α-olefin copolymer (A2) contains 60 to 95 mol % of a propylene-derived constitutional unit (a′) and 5 to 40 mol % of a C 4+ α-olefin-derived constitutional unit (b′), wherein a total amount of the constitutional unit (a′) and the constitutional unit (b′) is 100 mol %, and satisfies all of requirements below (i′) to (iii′):

(i′) a weight average molecular weight (Mw) measured by the GPC of 50,000 to 1,000,000;

(ii′) a melting point (Tm) measured by the DSC of 60 to 120° C.; and

(iii′) a half width of a crystalline melting point peak measured by the DSC of 1 to 20° C.

8. A resin composition comprising the modified propylene-α-olefin copolymer (A) according to claim 1 , and a second resin (B1),

wherein a weight ratio between the modified propylene-α-olefin copolymer (A) and the second resin (B1) is 1/99 to 90/10.

9. A coating material comprising 100 parts by weight of water or an organic solvent, and 0.1 to 100 parts by weight of the modified propylene-α-olefin copolymer (A) according to claim 1 dissolved or dispersed in the water or the organic solvent.

10. A coating material comprising 100 parts by weight of water or an organic solvent, and 0.1 to 100 parts by weight in total of the modified propylene-α-olefin copolymer (A) according to claim 1 and a second resin (B1) dissolved or dispersed in the water or the organic solvent,

wherein a weight ratio between the modified propylene-α-olefin copolymer (A) and the second resin (B1) is 1/99 to 90/10.

11. The coating material according to claim 9 , wherein the organic solvent has a solubility parameter value in a range of 7 to 12 (cal/cm 3 ) 1/2 .

12. The coating material according to claim 9 , wherein the organic solvent contains at least one selected from hydrocarbon-based solvents, alcohol-based solvents and ester-based solvents.

13. The coating material according to claim 9 , wherein the modified propylene-α-olefin copolymer (A) is completely dissolved in the organic solvent at a temperature of 50° C. or more.

14. A moldable resin composition comprising:

100 to 50 parts by weight of at least one resin (B2) selected from the group consisting of thermoplastic resins and thermosetting resins;

0 to 50 parts by weight of an inorganic reinforcing material (C), wherein a total amount of the resin (B2) and the reinforcing material (C) is 100 parts by weight; and

0.01 to 10 parts by weight of the modified propylene-α-olefin copolymer (A) according to claim 1 .

15. A hot melt composition comprising:

100 parts by weight of a base polymer (B3);

10 to 300 parts by weight of a tackifier (D); and

1 to 100 parts by weight of the modified propylene-α-olefin copolymer (A) according to claim 1 .

16. A paint comprising the modified propylene-α-olefin copolymer (A) according to claim 1 , or the modified propylene-α-olefin copolymer (A) according to claim 1 and a second resin (B1).

17. A primer comprising the modified propylene-α-olefin copolymer (A) according to claim 1 , or the modified propylene-α-olefin copolymer (A) according to claim 1 and a second resin (B1).

18. An adhesive comprising the modified propylene-α-olefin copolymer (A) according to claim 1 , or the modified propylene-α-olefin copolymer (A) according to claim 1 and a second resin (B1).

19. A pressure-sensitive adhesive comprising the modified propylene-α-olefin copolymer (A) according to claim 1 , or the modified propylene-α-olefin copolymer (A) according to claim 1 and a second resin (B1).

20. A sintering aid comprising the modified propylene-α-olefin copolymer (A) according to claim 1 , or the modified propylene-α-olefin copolymer (A) according to claim 1 and a second resin (B1).