Patent Application
20250215644
This application claims the benefit of Brazilian Application No. 10 2023 027868 0, filed on Dec. 29, 2023 the contents of which are hereby incorporated by reference in its entirety.
This document belongs to the field of Chemical Engineering, Paper, and Cellulose, and corresponds to a paper 100% composed of bleached short fiber cellulose, of high strength, comprising mineral filler, as well as its use in the production of kraftliner paper and wrappers, packaging boxes, corrugated paper and bags, and is suitable for food storage.
Papers for the production of kraftliner paper and other types of packaging are commonly produced on the market from blends of cellulose fibers, which are usually long fibers or a mixture of long and short fibers. This composition directly influences the quality of the material, as well as the desired strength depending on the product that will be produced from this paper.
In general, these papers can present a grammage between 70 and 440 g/m2, being most commonly found with a grammage between 90 and 170 g/m2.
The main desired characteristics of this type of paper are its rigidity, tear and burst resistance, as well as low porosity to achieve a better printability quality in products. Furthermore, for the material to be applicable in the production of packaging suitable for food storage, it also needs to be ideal for being in contact with such products.
One of the characteristics to analyze paper strength is fibrillation. With fibrillation, the exposure of hydroxyl groups increases, and, consequently, the number of bonds between fibers increases. This promotes greater product strength.
In general, it is described in the state of the art that for a paper to present good resistance characteristics, it is necessary to use long cellulose fiber. In other words, the longer the fiber, the greater its resistance, especially to tearing.
In addition, another characteristic to analyze the strength of the paper is fibrillation. With fibrillation, the exposure of hydroxyl groups increases, and, consequently, the number of bonds between fibers increases. This promotes greater strength of the product.
The present invention stands out from the state of the art and materials currently on the market primarily because it presents a paper with characteristics of resistance and printability quality for the production of kraftliner paper and paper packaging, among other products, being composed exclusively of bleached and fibrillated short fiber cellulose, also comprising mineral filler.
In a first aspect, the present invention provides a paper 100% composed of bleached and fibrillated short-fiber cellulose, which presents high resistance and comprises a mineral filler.
In a second aspect, the present invention provides that the fibers comprise a width between 10 and 20 μm and variable length between 0.2-3.2 mm. More specifically, the fibers are distributed in: 20-25% with length between 0.2-0.6 mm; 60-65% with length between 0.6-1.2 mm; 1-5% with length between 1.2-2.0 mm; 0.1-1.0% with average length between 2.0-3.2 mm. Furthermore, it also provides that fibrillation is between 0.2 and 0.4%, and the degree of straightness of the fiber is 90.
In a third aspect, the present invention provides that the short fiber comprises the following morphological characteristics:
In addition, the paper also presents a compression strength (RCT) of 0.5 to 2.0 kN/m.
In a fourth aspect, the present invention provides compostable and recyclable paper.
In a fifth aspect, the present invention provides that the paper presents smoothness and uniformity on its surface, conferring a high quality of printability. The smoothness is determined by the Bendtsen roughness, which comprises wire side Bendtsen roughness between 130 and 350 mL/min, and felt side Bendtsen roughness between 275 and 600 mL/min.
In a sixth aspect, the present invention provides that the paper is suitable for direct contact with food, in addition to having grammages between 70 and 210 g/m2. With this, the paper can be used in the production of wrappers, box packaging, corrugated and bags, in particular in food packaging, but not limited to these applications. The packaging produced by the paper claimed herein is also suitable for storing frozen or hot food.
In a seventh aspect, the present invention provides that the production of the paper claimed herein uses mineral filler of up to 10%, more specifically using calcium for the application of mineral filler.
Finally, the present invention provides that the paper is produced at a lower starch bath temperature and in the corrugator, with reduced energy and higher speed.
The various embodiments of the present invention will now be referred to in more details, from which one or more examples are shown in the experimental descriptions below. Each example is provided by way of illustration of the present invention, and should not be construed as a limitation thereof.
The high-strength paper claimed herein is characterized by the use of 100% bleached eucalyptus short fiber, reduced amount of mineral filler, and high levels of refining. In addition, the paper requires a low level of surface sizing and high compression strength values. This product line does not use bleach or dye to control optical properties.
Table 1 below presents a summary of the technical specifications of the physical properties of the paper claimed herein, which grammages can vary from 70 to 210 g/m2. It should be noted that the presented ranges vary according to the grammage of the product.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2023 027868 0 | Dec 2023 | BR | national |
