Patent Description:
As a result of growth in population in Turkey and as well as, in the world, paper usage increases but forest areas decrease which are the primary fiber source. As the primary fiber source decreases, the usage and the importance of management of secondary fiber sources increase. Since the amount of waste paper collected in Turkey is not sufficient, waste paper is imported from abroad for sustaining paper production. The amount of collected waste paper in Turkey was <NUM> million tones between years <NUM>-<NUM>, the amount of importation which has been <NUM> thousand tones in year <NUM> has increased in time and it has been <NUM> thousand tones in year <NUM>. Because of hygiene, easy storage, low-cost, easy and rapid supply, corrugated cardboard package products are increasingly preferred. At the end of year <NUM>, corrugated cardboard has <NUM>% of the paper-carton production capacity with the amount of corrugated cardboard equal to <NUM> million tones.

Corrugated cardboard is the general name given to papers formed by coating the under and/or top surfaces of one or more than one corrugated layer by means of a flat layer and used in production of package boxes and external parcels. Recycled paper is used in most of corrugated cardboard production. As the paper raw material in the world, waste papers are used with proportion of <NUM>-<NUM>% and cellulose is used with proportion of <NUM>-<NUM>%. It is estimated that half of the fibers used in paper production in the world is recycled and used again. In Turkey, the total of recycled paper used for paper production has reached <NUM> million tones in year <NUM>, and recycled paper has been used which is equal to <NUM>% of paper production.

Recycled paper, which can be used as package material in almost every sector and which has a high share as mentioned above, cannot be used as package material which contacts with food within the scope of the Turkish Food Codex, Regulation of Substances and Materials Which Contact With Food.

As a result, because of the abovementioned problems, an improvement is required in the related technical field.

The present invention relates to a package paper which is suitable for contact with food and the production process of package paper, for eliminating the abovementioned disadvantages and for bringing new advantages to the related technical field.

An object of the present invention is to provide a process for producing a package paper by making waste papers, which are suitable for recycling, suitable for contact with food.

An object of the present invention is to provide a package paper which has been made suitable for contact with food from and produced from waste paper which is suitable for recycling and at the same time which does not allow oil permeability.

An object of the present invention is to provide a package paper for corrugated boxes used for short-duration carrying of fatty foods.

An object of the present invention is to provide a package paper which is suitable for contact with food and which has reduced cost and which is environment-friendly.

In order to realize the abovementioned objects and the objects which are to be deducted from the detailed description below, the present invention is a package paper obtained from waste papers which are suitable for recycling. Accordingly, the improvement of the present invention is that the package paper has a barrier on its surface, said barrier is provided with a mixture comprising a starch aqueous solution which has dry starch at a proportion at least between <NUM>% and <NUM>% by weight of waste paper in a manner preventing oil permeability from one side to the other side, and a chemical material which has perfluoroalkyl group in cationic structure at a proportion between <NUM>% and <NUM>% by weight of paper.

In a possible embodiment of the present invention, the chemical material is perfluorohexylethyl methacrylate, <NUM>-N,N-diethylaminoethyl methacrylate, <NUM>-hydroxyethyl methacrylate and <NUM>,<NUM>'-ethylenedioxydiethyl dimethacrylate, malic acid salt copolymer.

In a possible embodiment of the present invention, the proportion of dry starch in starch aqueous solution is <NUM>-<NUM>%.

In a possible embodiment of the present invention, the viscosity of starch aqueous solution at speed of <NUM> rpm by means of rod with no <NUM> in Brookfield device is between <NUM> cp and <NUM> cp.

In another possible embodiment of the present invention, dry starch is provided at a proportion of <NUM>% of the waste paper by weight in starch aqueous solution, and chemical material is provided at a proportion of <NUM>% of waste paper by weight.

In another possible embodiment of the present invention, the mixture comprises adhesive such that there is water repellent characteristic for printing process.

The present invention is moreover a process for obtaining a package paper from waste papers which are suitable for recycling and comprising steps of making waste paper into fiber mixture form, diluting the fiber mixture and making into paper sheet form, and afterwards, drying in a first drying section. Accordingly, said improvement is that in order to provide a barrier on the surface of package paper in a manner preventing oil permeability from one side to the other side, a mixture, which comprises a starch aqueous solution including dry starch at a proportion between <NUM>% and <NUM>% by weight of waste paper and a chemical material which has perfluoroalkyl group in cationic structure at a proportion between <NUM>% and <NUM>% by weight of waste paper, is applied to the dried waste paper which is in paper sheet form having dry substance proportion between <NUM>-<NUM>% by weight in a film press section.

In another possible embodiment of the present invention, the process is realized by coating the mixture to the paper sheet with the help of sizer rods.

In another possible embodiment of the present invention, natural corn starch, which is cooked by modifying with enzyme, is used as dry starch.

In another possible embodiment of the present invention, the fiber mixture is subjected to refiner press and fibrillation process, such that Schopper riegler value of waste paper is between <NUM> and <NUM>, in a refiner unit in accordance with the refining level of waste paper.

In another possible embodiment of the present invention, adhesive is applied with the mixture to the waste paper which is in paper sheet form in order to provide water repellent characteristic for printing to the package paper.

In <FIG>, a representative view of the production process of the subject matter package paper is given.

In this detailed description, the subject matter package paper which is suitable for contact with food and the production process of package paper are explained with references to examples without forming any restrictive effect only in order to make the subject more understandable.

The subject matter package paper is obtained by subjecting the waste papers, which are suitable for recycling, to the process steps which shall be hereunder described.

In the first step, waste papers are disintegrated with water in a pulp unit (<NUM>) and are made into paper pulp form. Then, the paper pulp is cleaned by being passed through coarse screening and fine screening processes. The cleaned paper pulp is separated as long fiber and as short fiber in accordance with fiber lengths in pulp towers. Long fibers and short fibers are mixed with predetermined proportions and a fiber mixture is obtained. The fiber mixture is fibrillated in a refiner unit (<NUM>) and water retention and binding characteristics are increased. If the refining level of the waste paper is high during recycling, there may remain no need for the refiner press. If less amount of refined waste paper is used, refiner press is realized more. At the end of refiner press, the predetermined paper porosity must be reached. For white package paper, Schopper riegler value, which shows the freeness degree of the paper pulp and the drainage speed, is obtained as approximately <NUM> at the end of refiner press process. For brown package paper, Schopper riegler value is obtained approximately as <NUM>. At the end of refining process realized in the refiner unit (<NUM>) for the waste paper, Schopper riegler value is provided between <NUM> and <NUM>.

The diluted fiber mixture for forming wet paper sheet under a specific inner pressure in the pulp frame in the pulp unit (<NUM>) is sent onto long or short wire in a wire unit (<NUM>) by means of water jet method. Afterwards, the excessive water, which exists on the fiber mixture, is drained by vacuum. After paper sheet begins to be formed on the wire, it is carried on the felts, and the excessive water, which remains on the paper sheet, is removed by the pressure in a press unit (<NUM>). Thus, paper sheet is obtained where the dry weight thereof is between <NUM>-<NUM>% by weight. In the preferred application, the proportion of dry weight of waste paper, which is in paper sheet form, is provided as <NUM>%. The waste paper, where the dry weight proportion has reached a specific level, passes through drying cylinders at a first drying section (<NUM>) and the weight proportion of dry substance increases. The proportion of dry weight of waste paper has increased to between <NUM>-<NUM>% by weight at the end of the first drying section (<NUM>).

In the next step, resistance and barrier characteristics are provided to the waste paper, which is in paper sheet form, in a film press section (<NUM>). In other words, characteristics are provided which shall prevent at least oil permeability from one side to the other side of the package paper. This process is realized by means of applying of starch onto the paper sheet surface with the help of sizer rods. Natural corn starch is used which has been cooked by modifying with enzyme. The proportion of starch in aqueous solution has been determined as <NUM>-<NUM>%, and a starch aqueous solution with this concentration is used. In the preferred application, the concentration of starch aqueous solution is <NUM>%. When the viscosity of starch aqueous solution is measured at speed of <NUM> rpm by means of rod with no <NUM> in Brookfield device, a value of <NUM>-<NUM> cp is obtained. Moreover, the proportion of dry starch, which exists in the starch aqueous solution, to the dry waste paper is determined as <NUM>-<NUM>% by weight. In the preferred application, the starch aqueous solution is used such that its weight proportion to waste paper is <NUM>%. Meanwhile, in order to be able to use waste paper as a package paper so as to be suitable for contact with food, the barrier chemical is applied to the paper sheet with the help of starch, and a barrier is formed on the surface of the produced package paper.

As the barrier chemical, polymeric barrier chemicals, based on fluorocarbon with <NUM> carbons and with cationic, anionic structure, and barrier chemicals, which do not include fluorine, have been tested. As the barrier chemical, a chemical comprising cationic perfluoroalkyl group is used. The barrier chemical used in the preferred application is perfluorohexylethyl methacrylate, <NUM>-N,N-diethylaminoethyl methacrylate, <NUM>-hydroxyethyl methacrylate and <NUM>,<NUM>'-ethylenedioxydiethyl dimethacrylate, malic acid salt copolymer. <NPL> (copolymer of perfluorohexylethyl methacrylate, <NUM>-N,N-diethylaminoethyl methacrylate, <NUM>-hydroxyethyl methacrylate, and <NUM>,<NUM>'-ethylenedioxydiethyl dimethacrylate, malic acid salt).

The weight proportion of the barrier chemical to the waste paper is provided between <NUM>% and <NUM>%. In the preferred application, the barrier chemical is used such that its weight proportion to the waste paper is <NUM>%. A mixture is formed with starch and barrier chemical in the process detail, and said mixture is applied to the paper sheet. Such a mixture provides oil barrier characteristic to the package paper which is to be formed. Adhesive and water barrier can also be provided in the mixture accordingly. Since the adhesive and the water barrier are provided, the package paper can also have oil barrier characteristic and moreover, the water barrier can have water repellent characteristic for printing.

In the preferred application, since the waste paper, which is in paper sheet form and which enters the film press section (<NUM>), has <NUM>% moisture, it has been determined that the applied mixture stays in the best manner on the paper sheet surface.

After application of the mixture on the paper sheet and after the paper sheet is brought to the desired characteristics, drying process is applied in a second drying section (<NUM>). At the end of the second drying section (<NUM>), the dry weight proportion of the paper sheet is increased to between <NUM>% and <NUM>% by weight. At the end of these steps, the waste paper is made into a package paper form which is suitable for contact with food. The package paper is finally wrapped in a reel unit (<NUM>) as buffer paper roll.

Staying of the mixture, comprising barrier chemical, on the surface of the package paper without penetrating into the package paper, is an important criterion for being suitable to contact with food and thus for not permeate oil, and as also mentioned above, this is produced by decreasing paper porosity by means of refiner press setting.

The tests of the package paper, which details are given above, have been made in laboratory scale and it has been detected whether it penetrates water and oil or not and whether the barrier is suitable or not. Accordingly, the recipe of the barrier mixture and the suitable process conditions have been determined. The tests have been realized in accordance with Tappi T559 - Grease Resistance Test for Paper and Paperboard test method. In Table <NUM>, the test results have been given in the case where the barrier chemical, with the details as given above, is used.

By means of the parameters given in Table <NUM> and given in process details, it has been determined that water does not penetrate for <NUM> seconds and warm oil does not penetrate for <NUM> seconds and hot oil at 55ºC does not penetrate for <NUM> minutes from one side to the other side of the package paper.

By means of a package paper provided in this manner, corrugated boxes are formed which are used for carrying fatty foods. During carrying of pizza, lahmacun, pita, etc, there is no oil permeability in the package paper. Moreover, in case adhesive is applied, the package paper does not permit water penetration.

Claim 1:
A package paper obtained from waste paper which is suitable for recycling, characterized in that it contains a barrier on its surface to prevent the passage of oil from one side to the other, comprising dry starch of at least <NUM> to <NUM>% by weight of the wastepaper and a chemical material having a perfluoroalkyl group of cationic nature in a proportion of <NUM> to <NUM>% by weight of the wastepaper.