Graft-modified propylene α-olefin copolymers and methods for producing the same

1. An aqueous dispersion comprising a graft-modified propylene.α-olefin copolymer (A) obtained by graft-reacting a polar monomer onto a propylene.α-olefin copolymer (a) comprising 50 to 90 mol % of propylene-derived structural units (C3) and 10 to 50 mol % of C4-8 α-olefin-derived structural units (Cα) (wherein the total of the structural units C3 and Cα is 100 mol %), the graft-modified propylene.α-olefin copolymer satisfying the following requirements (i) to (iv) at the same time:

(i) the amount of the polar monomer grafted is 0.4 to 1.5 wt %,

(ii) the content of the polar monomer is not more than 1000 ppm,

(iii) the content of a gel insoluble in xylene at 140° C. is not more than 2.5 wt %, and

(iv) the content of a volatile hydrocarbon compound is not more than 10 ppm.

2. The aqueous dispersion according to claim 1 , wherein the graft-modified propylene.α-olefin copolymer (A) has an intrinsic viscosity measured at 135° C. in decalin of 0.5 to 1.0 (dl/g).

3. The aqueous dispersion according to claim 1 , wherein the propylene.α-olefin copolymer (a) satisfies the following requirements (1) to (3):

(1) the intrinsic viscosity measured at 135° C. in decalin is 0.1 to 12 (dl/g),

(2) the molecular weight distribution (Mw/Mn) measured by gel permeation chromatography (GPC) relative to polystyrenes is not more than 3.0, and

(3) the parameter value B representing a randomness of a comonomer sequence distribution is 1.0 to 1.5.

4. The aqueous dispersion according to claim 1 , wherein the C4-8 α-olefin is 1-butene.

5. The aqueous dispersion according to claim 4 , wherein the propylene.α-olefin copolymer (a) further satisfies the requirements (4) and (5):

(4) the melting point Tm measured by differential scanning calorimetry (DSC) is 60 to 140° C., and the melting point Tm (T° C.) and the content of 1-butene-derived structural units (M mol %) satisfy −2.6M+130≤T≤−2.3M+155, and

(5) the degree of crystallinity (C %) measured by X-ray diffractometry and the content of 1-butene-derived structural units (M mol %) satisfy C≥−1.5M+75.

6. The aqueous dispersion according to claim 1 , wherein the polar monomer is maleic acid or maleic anhydride.

7. The aqueous dispersion according to claim 1 , wherein the graft-modified propylene.α-olefin copolymer (A) is produced by modifying the propylene.α-olefin copolymer (a) by melt-kneading, at a temperature of 120 to 220° C., a mixture including the propylene.α-olefin copolymer (a), 0.1 to 20 parts by weight of maleic anhydride (B) per 100 parts by weight of the copolymer (a), and 0.1 to 1.0 part by weight of an organic peroxide (C) per 100 parts by weight of the copolymer (a), the organic peroxide having a one-minute half-life decomposition temperature of 150 to 190° C.

8. A method for producing an aqueous dispersion of a graft modified propylene α-olefin copolymer (A) in which a graft modified propylene α-olefin copolymer (A) is dispersed and in which the graft modified propylene α-olefin copolymer (A) is obtained by graft-reacting a polar monomer onto a propylene.α-olefin copolymer (a) comprising 50 to 90 mol % of propylene-derived structural units (C3) and 10 to 50 mol % of C4-8 α-olefin-derived structural units (Cα) (wherein the total of the structural units C3 and Cα is 100 mol %), the graft-modified propylene.α-olefin copolymer satisfying the following requirements (i) to (iv) at the same time:

(i) the amount of the polar monomer grafted is 0.4 to 1.5 wt %,

(ii) the content of the polar monomer is not more than 1000 ppm,

(iii) the content of a gel insoluble in xylene at 140° C. is not more than 2.5 wt %, and

(iv) the content of a volatile hydrocarbon compound is not more than 10 ppm, comprising modifying a propylene.α-olefin copolymer (a) by melt-kneading, at a temperature of 120 to 220° C., a mixture including the propylene.α-olefin copolymer (a), 0.1 to 20 parts by weight of maleic anhydride (B) per 100 parts by weight of the copolymer (a), and 0.1 to 1.0 part by weight of an organic peroxide (C) per 100 parts by weight of the copolymer (a), the organic peroxide having a one-minute half-life decomposition temperature of 150 to 190° C.

9. A resin composition comprising a graft-modified polypropylene.α-olefin copolymer (A), obtained by graft-reacting a polar monomer onto a propylene.α-olefin copolymer (a) comprising 50 to 90 mol % of propylene-derived structural units (C3) and 10 to 50 mol % of C4-8 α-olefin-derived structural units (Cα) (wherein the total of the structural units C3 and Cα is 100 mol %), the graft-modified propylene.α-olefin copolymer satisfying the following requirements (i) to (iv) at the same time:

(i) the amount of the polar monomer grafted is 0.4 to 1.5 wt %,

(ii) the content of the polar monomer is not more than 1000 ppm,

(iii) the content of a gel insoluble in xylene at 140° C. is not more than 2.5 wt %, and

(iv) the content of a volatile hydrocarbon compound is not more than 10 ppm,

and one or more resins selected from polyamide resins and polypropylene resins.

10. A method of producing a resin composition containing a graft modified propylene α-olefin copolymer (A) in which a graft modified propylene α-olefin copolymer (A) is blended with one or more resins selected from polyamide resins and polypropylene resins and in which the raft modified propylene α-olefin copolymer (A) is obtained by graft-reacting a polar monomer onto a propylene.α-olefin copolymer (a) comprising 50 to 90 mol % of propylene-derived structural units (C3) and 10 to 50 mol % of C4-8 α-olefin-derived structural units (Cα) (wherein the total of the structural units C3 and Cα is 100 mol %), the graft-modified propylene.α-olefin copolymer satisfying the following requirements (i) to (iv) at the same time:

(i) the amount of the polar monomer grafted is 0.4 to 1.5 wt %,

(ii) the content of the polar monomer is not more than 1000 ppm,

(iii) the content of a gel insoluble in xylene at 140° C. is not more than 2.5 wt %, and

(iv) the content of a volatile hydrocarbon compound is not more than 10 ppm, comprising modifying a propylene.α-olefin copolymer (a) by melt-kneading, at a temperature of 120 to 220° C., a mixture including the propylene.α-olefin copolymer (a), 0.1 to 20 parts by weight of maleic anhydride (B) per 100 parts by weight of the copolymer (a), and 0.1 to 1.0 part by weight of an organic peroxide (C) per 100 parts by weight of the copolymer (a), the organic peroxide having a one-minute half-life decomposition temperature of 150 to 190° C.