Barrier coatings

Patent metadata

Field	Value
Publication number	US-10934448-B2
Application number	US-201616060339-A
Country	US
Kind code	B2
Filing date	Dec 7, 2016
Priority date	Dec 9, 2015
Publication date	Mar 2, 2021
Grant date	Mar 2, 2021

Abstract

A barrier coating composition comprising a starch material characterised in that the starch material has a weight average molecular weight of 50.000 to 1.000.000 Dalton and a glass transition temperature (Tg) of no more than 120° C.

First claim

The invention claimed is:

1. A barrier coating composition comprising:
a starch material, wherein the starch material has a weight average molecular weight of 25,000 to 1,000,000 Dalton and a glass transition temperature (Tg) of no more than 120° C.;
a synthetic polymer, wherein the synthetic polymer is selected from the group consisting of polyvinyl alcohol, a polyamine, a polyacrylate, a polyamide, and a mixture thereof, and the starch material and the synthetic polymer are in a dry weight ratio of 1:2 to 2:1; and
a water-soluble plasticizer that is a polyol;
wherein a barrier coating layer comprising the barrier coating composition has a hexane permeability of no more than 50 g/m 2 d and a grease resistance of at least 3.

2. The barrier coating composition according to claim 1 , wherein it has a dry solid content greater than 15-75% by weight.

3. The barrier coating composition according to claim 1 , wherein it is suitable for curtain coating of cellulose-based substrates.

4. The barrier coating composition according to claim 1 , wherein it has a Brookfield viscosity of 300-1100 mPa·s, when measured at 20° C., 100 rpm, and with a no. 4 spindle.

5. The barrier coating composition according to claim 1 , wherein it further comprises a pigment.

6. A paper product comprising a cellulose-based substrate and a barrier coating layer, wherein
a) the barrier coating layer comprises the composition of claim 1 ;
b) the barrier coating layer has an average thickness of at least 3 μm and an average coat weight of 5 to 20 g/m 2 ; and
c) the starch material has a weight average molecular weight of 50,000 to 1,000,000 Dalton and a glass transition temperature (Tg) of no more than 120° C.

7. The paper product according to claim 6 , wherein the plasticizer is selected from the group consisting of a glycol, glycerol, sorbitol, glucose and mixtures thereof.

8. The paper product according to claim 6 for use as a packaging material.

9. A process for the production of a paper product comprising at least one barrier coating layer, comprising coating a cellulose-based substrate with a barrier coating composition according to claim 1 .

10. A method of preventing migration of mineral oils through a cellulose-based substrate, the method comprising applying the barrier coating composition of claim 1 to a cellulose-based substrate.

11. The barrier coating composition of claim 1 , wherein the starch material is a dextrin, and the plasticizer is sorbitol, glucose, or a mixture thereof.

12. The barrier coating composition of claim 1 , wherein the starch material is a mixture of dextrin and a waxy starch.

13. The barrier coating composition of claim 12 , wherein the dextrin and the waxy starch are present in a weight ratio of 50:50 to 20:1.

14. The barrier coating composition of claim 11 , wherein the dextrin is a thermally modified starch.

15. The barrier coating composition of claim 1 , wherein the starch consists of a thermally modified starch (TMS), a dextrin, a waxy starch, or a mixture thereof.

16. The barrier coating composition of claim 1 , wherein the plasticizer is glycol, glycerol, sorbitol, glucose, or a mixture thereof.

17. The barrier coating composition of claim 1 , wherein the plasticizer is sorbitol and the synthetic polymer is polyvinyl alcohol.

18. The barrier coating composition of claim 1 , wherein a barrier coating layer comprising the barrier coating composition has a hexane permeability of no more than 20 g/m 2 d and a grease resistance of at least 5.

19. The barrier coating composition of claim 1 , wherein the synthetic polymer is 5-50 wt % by dry weight of the barrier coating composition.

20. The barrier coating composition of claim 1 , wherein the plasticizer is 3-40 wt % by dry weight of the barrier coating composition.

Assignees

• Cargill Inc

Inventors

• Brighenti Mercedes
• Meinders Olaf
• Sivasligil Dogan Sahin
• Thalhofer Richard

Classifications

• D21H19/00

  Coated paper (coated fibreboard D21J1/08); Coating material (recording sheets characterised by the coating used to improve ink, dye or pigment receptivity B41M5/50) · CPC title

• B32B9/06

  of paper or cardboard · CPC title

• B32B9/02

  comprising animal or vegetable substances {, e.g. cork, bamboo, starch} · CPC title

• B32B2307/7265

  Non-permeable · CPC title

• B32B2439/70

  Food packaging · CPC title