Method of printing at least one transparent area on a major surface of a non-coated paper or cardboard substrate (1), wherein an optical transmittance, as measured with spectrophotometry, through the substrate (1) at a printed transparent area (2) is at least 20% higher than through the substrate (1) at a non-printed area (3) of the same paper or cardboard 5 substrate (1) at a wavelength in the electromagnetic spectrum of wavelengths from 400 nm to 1000 nm that.

The invention relates to a supercalendered Kraft paper production for a release liner, which contains both non-recycled bleached chemical pulps and recycled pulp produced from release liner supercalendered Kraft paper. When highly specific raw material is used for recycling, the characteristics of the recycled pulp may be adjusted already upon recycling. The recycled pulp obtained from supercalendered Kraft paper that has been used as a substrate of a release liner may be used without further refining for manufacturing supercalendered Kraft paper. Excessive refining can thus be avoided and the compatibility of the recycled pulp may be optimized for supercalendered Kraft paper production. The non-recycled pulps may be refined less, as well. This leads to positive effects in supercalendered Kraft paper manufacturing process, such as improved dewatering and energy efficient drying. The produced paper demonstrates reduced shrinkage and improved dimensional stability, while maintaining sufficient quality for use as a substrate for a release liner. A supercalendered Kraft paper with improved sustainability is produced.

A method of forming glass-like sheets using date palm seeds is provided. The method includes milling date palm seeds to form a powder. The powder is compressed to form discs, after which the discs are immersed in a delignification solution followed by removal from the delignification solution and washing. The discs formed from the date palm seed powder are immersed in a bleaching solution until a change in color is observed from opaque to transparent. The transparent discs thus formed are then hardened through application of an epoxy resin. The initial grinding procedure may be substituted by an initial slicing step of the date palm seeds in a similar method of forming the glass-like sheets.

The invention relates to a supercalendered Kraft paper production for a release liner, which contains both non-recycled bleached chemical pulps and recycled pulp produced from release liner supercalendered Kraft paper. When highly specific raw material is used for recycling, the characteristics of the recycled pulp may be adjusted already upon recycling. The recycled pulp obtained from supercalendered Kraft paper that has been used as a substrate of a release liner may be used without further refining for manufacturing supercalendered Kraft paper. Excessive refining can thus be avoided and the compatibility of the recycled pulp may be optimized for supercalendered Kraft paper production. The non-recycled pulps may be refined less, as well. This leads to positive effects in supercalendered Kraft paper manufacturing process, such as improved dewatering and energy efficient drying. The produced paper demonstrates reduced shrinkage and improved dimensional stability, while maintaining sufficient quality for use as a substrate for a release liner. A supercalendered Kraft paper with improved sustainability is produced.

The invention relates to a supercalendered Kraft paper production for a release liner, which contains both non-recycled bleached chemical pulps and recycled pulp produced from release liner supercalendered Kraft paper. When highly specific raw material is used for recycling, the characteristics of the recycled pulp may be adjusted already upon recycling. The recycled pulp obtained from supercalendered Kraft paper that has been used as a substrate of a release liner may be used without further refining for manufacturing supercalendered Kraft paper. Excessive refining can thus be avoided and the compatibility of the recycled pulp may be optimized for supercalendered Kraft paper production. The non-recycled pulps may be refined less, as well. This leads to positive effects in supercalendered Kraft paper manufacturing process, such as improved dewatering and energy efficient drying. The produced paper demonstrates reduced shrinkage and improved dimensional stability, while maintaining sufficient quality for use as a substrate for a release liner. A supercalendered Kraft paper with improved sustainability is produced.

Transparent paper consisting of a coated or chemically treated kraft paper, wherein the kraft paper is formed from a bleached, low-consistency and possibly high-consistency pulp beaten with a beating degree of at least 38 SR, which is formed to an extent of at least 30%, and at most 60% of softwood pulp and to an extent of at least 35%, of hardwood pulp, and optionally further fibrous materials, 0.5 to 2.5% cationic starch, processing aids, 0.1 to 0.4% sizing agent and optionally up to 4% fillers, and wherein the kraft paper is mechanically surface-treated with further substances selected from PEG, glycerol, polyvinyl alcohol or mixtures of two or more thereof, and starch, as well as methods for producing transparent paper and forming a kraft pulp.