Paper container

1. A paper container having a window and being formed of a laminate that comprises at least a paper layer, a gas barrier laminate, and a polypropylene layer,

the paper layer having a cutout part for the window,

the cutout part being hollow and covered on an inner side and/or an outer side with the gas barrier laminate, and

the gas barrier laminate comprising a substrate and a gas barrier layer laminated on at least one surface of the substrate,

wherein the gas barrier layer is formed of a composition comprising:

a polymer having at least one functional group selected from a carboxyl group and a carboxylic anhydride group, wherein at least 40 mol % of a —COO— group contained in the at least one functional group has been neutralized with a metal ion having a valence of two or more; and

a hydrolysis condensation product of at least one compound (L) containing a metal atom to which at least one characteristic group selected from a halogen atom and an alkoxy group has been bonded, wherein the compound (L) comprises:

at least one compound (A) represented by the following Chemical Formula (I):

M 1 (OR 1 ) n X 1 k Z m−n−k   (I),

where M 1 represents Si, Al, Ti, Zr, Cu, Ca, Sr, Ba, Zn, B, Ga, Y, Ge, Pb, P, Sb, V, Ta, W, La, or Nd, R 1 represents an alkyl group, X 1 represents a halogen atom, Z represents an alkyl group having a substituted functional group reactive with a carboxyl group, m is equal to a valence of M 1 , n is an integer of 0 to (m−1), k is an integer of 0 to (m−1), and 1<n+k<(m−1); and

at least one compound (B) represented by the following Chemical Formula (II):

M 2 (OR 2 ) q R 3 p−q−r X 2 r   (II)

where M 2 represents Si, Al, Ti, Zr, Cu, Ca, Sr, Ba, Zn, B, Ga, Y, Ge, Pb, P, Sb, V, Ta, W, La, or Nd, R 2 represents an alkyl group, R 3 represents an alkyl group, an aralkyl group, an aryl group, or an alkenyl group, X 2 represents a halogen atom, p is equal to a valence of M 2 , q is an integer of 0 to p, r is an integer of 0 to p, and 1<q+r<p, and

wherein a molar ratio of the compound (A) / the compound (B) is from 0.5/99.5 to 40/60.

2. The paper container according to claim 1 , wherein in Chemical Formula (I), the substituted functional group reactive with a carboxyl group is at least one functional group selected from the group consisting of an epoxy group, an amino group, a halogen group, a mercapto group, an isocyanate group, a ureide group, and a hydroxyl group.

3. The paper container according to claim 1 , wherein the polymer is at least one polymer selected from a polyacrylic acid and a polymethacrylic acid.

4. The paper container according to claim 1 , wherein the metal ion is at least one ion selected from the group consisting of a calcium ion, a magnesium ion, a barium ion, and a zinc ion.

5. The paper container according to claim 1 , wherein the gas barrier laminate further comprises a layer formed of an inorganic material obtained by a vapor deposition method, between the substrate and the layer laminated on at least one surface of the substrate.

6. The paper container according to claim 1 , wherein a part other than the cutout part of the paper layer consists essentially of a paper layer, a gas barrier laminate and at least one polyolefin layer.

7. The paper container according to claim 1 , the cutout part being hollow, uncovered on the outer side, and covered on the inner side with the gas barrier laminate.

8. The paper container according to claim 1 , the cutout part being hollow, uncovered on the inner side, and covered on the outer side with the gas barrier laminate.

9. The paper container according to claim 1 , the cutout part being hollow and covered on the inner side and the outer side with the gas barrier laminate.

10. A retort paper container comprising a paper layer, a heat-resistant polyolefin layer, and a gas barrier laminate,

wherein the heat-resistant polyolefin layer is non-stretched and arranged as an innermost layer,

wherein the gas barrier laminate comprises a substrate and a gas barrier layer laminated on at least one surface of the substrate,

wherein the gas barrier layer is formed of a composition comprising:

a polymer having at least one functional group selected from a carboxyl group and a carboxylic anhydride group, wherein at least 40 mol % of a —COO— group contained in the at least one functional group has been neutralized with a metal ion having a valence of two or more; and

a hydrolysis condensation product of at least one compound (L) containing a metal atom to which at least one characteristic group selected from a halogen atom and an alkoxy group has been bonded, wherein the compound (L) comprises:

at least one compound (A) represented by the following Chemical Formula (I):

M 1 (OR 1 ) n X 1 k Z m−n−k   (I),

where M 1 represents Si, Al, Ti, Zr, Cu, Ca, Sr, Ba, Zn, B, Ga, Y, Ge, Pb, P, Sb, V, Ta, W, La, or Nd, R 1 represents an alkyl group, X 1 represents a halogen atom, Z represents an alkyl group having a substituted functional group reactive with a carboxyl group, m is equal to a valence of M 1 , n is an integer of 0 to (m−1), k is an integer of 0 to (m−1), and 1<n+k<(m−1); and

at least one compound (B) represented by the following Chemical Formula (II):

M 2 (OR 2 ) q R 3 p−q−r X 2 r   (II)

where M 2 represents Si, Al, Ti, Zr, Cu, Ca, Sr, Ba, Zn, B, Ga, Y, Ge, Pb, P, Sb, V, Ta, W, La, or Nd, R 2 represents an alkyl group, R 3 represents an alkyl group, an aralkyl group, an aryl group, or an alkenyl group, X 2 represents a halogen atom, p is equal to a valence of M 2 , q is an integer of 0 to p, r is an integer of 0 to p, and 1<q+r<p,

wherein a molar ratio of the compound (A)/the compound (B) is from 0.5/99.5 to 40/60, and

wherein the retort paper container has an oxygen transmission rate of 3.2 cc/m 2 ·day·atm or less after a retort process.

11. The retort paper container according to claim 10 , wherein in Chemical Formula (I), the functional group reactive with a carboxyl group is at least one functional group selected from the group consisting of an epoxy group, an amino group, a halogen group, a mercapto group, an isocyanate group, a ureide group, and a hydroxyl group.

12. The retort paper container according to claim 10 , wherein the polymer is at least one polymer selected from a polyacrylic acid and a polymethacrylic acid.

13. The retort paper container according to claim 10 , wherein the metal ion is at least one ion selected from the group consisting of a calcium ion, a magnesium ion, a barium ion, and a zinc ion.

14. The retort paper container according to claim 10 , wherein the gas barrier laminate further comprises a layer formed of an inorganic material obtained by a vapor deposition method, between the substrate and the layer laminated on at least one surface of the substrate.

15. The retort paper container according to claim 10 , wherein the heat-resistant polyolefin layer is a polypropylene layer.

16. The retort paper container according to claim 10 , wherein the retort paper container has a cutout part for a window, the cutout part being hollow and covered on an inner side and/or an outer side with at least the gas barrier layer.

17. The retort paper container according to claim 10 , wherein the oxygen transmission rate is measured at 20° C. and 85% RH.

18. The retort paper container according to claim 10 , wherein the retort process is carried out at 120° C. for 30 minutes.

19. The retort paper container according to claim 16 , the cutout part being hollow, uncovered on the outer side, and covered on the inner side with the gas barrier laminate.

20. The retort paper container according to claim 16 , the cutout part being hollow, uncovered on the inner side, and covered on the outer side with the gas barrier laminate.

21. The retort paper container according to claim 16 , the cutout part being hollow and covered on the inner side and the outer side with the gas barrier laminate.