Low basis weight inkjet printable substrates with lower showthrough and improved waterfastness and print density

Patent metadata

Field	Value
Publication number	US-2018126764-A1
Application number	US-201815865543-A
Country	US
Kind code	A1
Filing date	Jan 9, 2018
Priority date	Sep 30, 2015
Publication date	May 10, 2018
Grant date	—

Abstract

An article in the form of a printable substrate having a showthrough value of about 0.14 or less, and an opacity value of at least about 88% which includes a paper substrate with a first and second surfaces formed of paper fibers having a basis weight of from about 12 to about 32 lbs/1300 ft 2 , and a substrate filler in an amount in the range of from 0 to about 30% by weight of the paper substrate; and a surface size layer on at least one of the first and second surfaces, the surface size layer having about 50 lbs or less per ton of the paper substrate of a starch surface sizing agent and a multivalent metal salt drying agent in an amount sufficient to impart to the at least one of the first and second surfaces a black print density value of at least about 0.8 when inkjet printed with pigmented inks and a waterfastness value of at least about 85% when inkjet printed with dye-based inks, the printable substrate having a MD tensile strength of at least about 12 lbs/in. and a CD tensile strength of at least about 6 lbs/in. Also, a method for preparing such a printable substrate.

First claim

What is claimed is:

1 . An article comprising a printable substrate, the printable substrate comprising:
a paper substrate having a first surface and a second surface, a basis weight of from about 12 to about 32 lbs/1300 ft 2 , a showthrough value of about 0.14 or less, and an opacity value of at least about 88%, the paper substrate comprising:
paper fibers in an amount of from 60 to 100% by weight of the paper substrate; and
a substrate filler in an amount from 0 to about 30% by weight of the paper substrate; and
a surface size layer on at least one of the first and second surfaces, surface size layer comprising:
about 50 lbs or less per ton of the paper substrate of a starch surface sizing agent; and
a multivalent metal salt drying agent in an amount sufficient to impart to the at least one of the first and second surfaces a black print density value of at least about 0.8 when inkjet printed with pigmented inks and a waterfastness value of at least about 85% when inkjet printed with dye-based inks;
wherein the printable substrate has a MD tensile strength of at least about 12 lbs/in. and a CD tensile strength of at least about 6 lbs/in.

2 . The article of claim 1 , wherein the surface size layer is on both the first and second surfaces.

3 . The article of claim 1 , wherein the multivalent metal salt drying agent comprises calcium chloride.

4 . The article of claim 1 , wherein the paper substrate has a basis weight of from about 15 to about 25 lbs/1300 ft 2 .

5 . The article of claim 4 , wherein the paper substrate has a basis weight of from about 18 to about 20 lbs/1300 ft 2 .

6 . The article of claim 1 , wherein the substrate filler comprises from about 10 to about 25% by weight of the paper substrate.

7 . The article of claim 6 , wherein the substrate filler comprises from about 15 to about 20% by weight of the paper substrate.

8 . The article of claim 6 , wherein the substrate filler comprises calcium carbonate.

9 . The article of claim 6 , wherein the paper substrate further comprises a cationic starch binder in amount in the range of from about 0.05 to about 3% by weight of the paper substrate.

10 . The article of claim 9 , wherein the paper substrate comprises the cationic starch binder in amount in the range of from about 0.1 to about 2% by weight of the paper substrate.

11 . The article of claim 1 , wherein the surface size layer comprises about 25 lbs or less per ton of the paper substrate of a starch surface sizing agent.

12 . The article of claim 11 , wherein the surface size layer comprises about 10 lbs or less per ton of the paper substrate of a starch surface sizing agent.

13 . The article of claim 12 , wherein the surface size layer comprises from about 0.1 to about 10 lbs or less per ton of the paper substrate of a starch surface sizing agent.

14 . The article of claim 13 , wherein the starch surface sizing agent comprises ethylated starch.

15 . The article of claim 1 , wherein the opacity value of the printable substrate is at least about 90% and wherein the showthrough value is about 0.13 or less.

16 . The article of claim 15 , wherein the opacity value of the printable substrate is at least about 92% and wherein the showthrough value is about 0.12 or less.

17 . The article of claim 1 , wherein the amount of multivalent metal salt drying agent present in surface size layer is sufficient to impart a black print density value of at least about 1.2, and wherein the waterfastness value is at least about 90%.

18 . The article of claim 1 , wherein the paper substrate comprises about 10 to about 40% by weight softwood fibers and from about 60 to about 90% by weight hardwood fibers.

19 . The article of claim 1 , wherein the black print density value is at least about 1.0.

20 . The article of claim 19 , wherein the black print density value is at least about 1.2.

21 . The article of claim 1 , wherein the printable substrate has a MD tensile strength of from about 25 to about 35 lbs/in. and a CD tensile strength of from about 8 to about 12 lbs/in.

22 . The article of claim 1 , wherein the paper substrate has an HST value of from about 5 to about 350 seconds.

23 . The article of claim 22 , wherein the paper substrate has an HST value of from about 10 to about 100 seconds.

24 . A method for preparing a printable substrate, which comprises the following steps:
(a) providing a paper substrate having a first surface and a second surface and having a basis weight of from about 12 to about 32 lbs/1300 ft 2 , the paper substrate comprising:
paper fibers in an amount in the range of from about 60 to 100% by weight of the paper substrate; and
a substrate filler in an amount in the range of from 0 to about 30% by weight of the paper substrate; and
(b) forming on at least one of the first and second surfaces a surface size layer to provide the printable substrate having a showthrough value of about 0.14 or less, and an opacity value of at least about 88%; (c) wherein the surface size layer of step (b) comprises about 50 lbs or less per ton of the paper substrate of a starch surface sizing agent; (d) wherein the surface size layer of step (b) comprises a multivalent metal salt drying agent in an amount sufficient to impart to the at least one of the first and second surfaces a black print density value of at least about 0.8 when inkjet printed with pigmented inks and a waterfastness value of at least about 85% when inkjet printed with dye-based inks; (e) wherein the printable substrate of step (b) has a MD tensile strength of at least about 12 lbs/in. and a CD tensile strength of at least about 6 lbs/in.

25 . The method of claim 24 , wherein a surface size layer is formed on both the first and second surfaces during step (b).

26 . The method of claim 24 , wherein step (b) is carried out by applying a surface size composition comprising the multivalent metal salt drying agent and the optional starch surface sizing agent to at least one of the first and second surfaces with a size press to form the surface size layer.

27 . The method claim 24 , wherein the size press is a rod metering size press.

28 . The method of claim 24 , wherein the size press is flooded nip size press.

29 . The method of claim 24 , wherein the substrate filler comprises from about 10 to about 25% by weight of the paper substrate of step (a).

30 . The method of claim 29 , wherein the substrate filler comprises from about 15 to about 20% by weight of the paper substrate of step (a).

31 . The method of claim 24 , wherein the substrate filler of step (a) comprises calcium carbonate.

32 . The method of claim 24 , wherein the paper substrate of step (a) comprises cationic starch binder in the range of from about 0.05 to about 3% by weight of the paper substrate.

33 . The method of claim 32 , wherein the paper substrate of step (a) comprises cationic starch binder in the range of from about 0.1 to about 2% by weight of the paper substrate.

34 . The method of claim 24 , wherein the surface size layer formed during step (b) comprises from about 0.1 to about 10 lbs or less per ton of the paper substrate of a starch surface sizing agent.

35 . The method of claim 24 , wherein th

Assignees

• Int Paper Co

Inventors

• Singh Kapil M

Classifications

• D21H23/56

  Rolls (D21H23/38 takes precedence) · CPC title

• D21H21/16

  Sizing or water-repelling agents · CPC title

• B41M5/5227

  characterised by organic non-macromolecular additives, e.g. UV-absorbers, plasticisers, surfactants · CPC title

• B41M5/5218

  characterised by inorganic additives, e.g. pigments, clays · CPC title

• B05D1/00

  Processes for applying liquids or other fluent materials (B05D5/00, B05D7/00 take precedence) · CPC title