Heat, Grease, And Cracking Resistant Release Paper And Process For Producing The Same

Abstract

A heat, grease, and cracking resistance release paper, said release paper is composed by 55% to 68% by weight of cellulose fiber, 3% to 6% by weight of one or more sizing agents, 27% to 37% by weight of one or more fillers, and 1% to 3% by weight of one or more binding agents.

Description

TECHNICAL FIELD OF THE INVENTION

[0001] The present invention relates to papermaking processes and products made through these processes. More particularly, the invention relates to a composition and a process for obtaining a heat, grease, and cracking resistant release paper, starting from the combination of cellulose fiber, one or more sizing agents, one or more fillers, and one or more binding agents.

BACKGROUND OF THE INVENTION

[0002] At present, a variety of paper used to wrap fatty foods, consists of cellulose fibers or derivatives to which a mixture of oil, grease or wax is added with organic dissolvents; said mixture is added during or after the production of the development paper pulp, which is then treated by heat and pressure to obtain a greaseproof paper. However, this paper proves to be inconvenient to wrap food, because of the possible risk of dissolvent residues, also it can not be used to warm foods wrapped in it as it does not withstand high temperatures.

[0003] Another current variation of greaseproof paper used to wrap foods is the paper coated with paraffin on one or both sides, and for the manufacture of which liquid wax is applied in conventional coating machines and with a rubber cylinder to reduce the coating to a suitable thickness. The disadvantages of this type of papers are that the hard paraffin papers are cracking at the least flexion, whereas the smooth paraffin papers release grease, and particularly they are not appropriate to wrap sensitive products to said papers, moreover they cannot be submitted to high temperatures in order to warm wrapped foods.

[0004] One more variant of greaseproof paper used to wrap foods, are so-called plastic-coated papers laminated on one or both sides. This type of paper has the disadvantage that it can not be submitted to high temperatures, because of the risk of being consumed and releasing toxic components.

[0005] Other grease resistant or greaseproof types of paper are described in the following patent documents:

[0006] Donald K. Pattilloch and Carl Polowczyk, in U.S. Pat. No. 2,957,796 A1, describe a resistent paper made from the reaction of cellulose fibers with polyethyleneimine and perfluoroalkanoic acid.

[0007] Ajit S. Dixit, et al., in U.S. Pat. No. 7,019,054 B2, describe a oil and grease resistant paper made from the reaction of cellulose fibers with polyvinyl alcohol and fatty-acid melanin wax.

[0008] Charles W. Propst Jr, in the US patent application US-2004/185286 A1, describes a grease, oil or wax resistant paper made from a substratum of cellulose fibers, covered with a layer based on a material serving as a filler material selected from clay, sodium hexametaphosphate, titanium dioxide and talc; a binding agent selected from latex, polyvinyl chloride, polyvinyl acetate, acrylate, maleic acid and protein; and calcium carbonate basically free from surfactants.

[0009] Richard F. Rudolph, et al., in the published international patent application WO-07014148, describes a grease resistant paper with glueability properties formed by cellulose fibers with a fluorocarbon-containing compound, so that this compound is dispersed from 5% to 100% in the web of cellulose fibers.

[0010] The limitation of these papers described in said patent documents is their low resistance to heat; therefore, a food product that is wrapped with this paper can not be heated in an oven.

[0011] In view of this, exist the so-called heat or high temperature resistant papers, which can be used to wrap food and heat it in this way in an oven, however, these papers have the limitation that they are not waterproof or resistant to grease or liquids. Examples of these heat resistant papers are described in the following patent documents:

[0012] Uwe Becker in the publication of the European patent application EP-1,000,198, describes a high temperature resistant paper composed of a mixture of cellulose fibers and silica fibers, cut and thermally contracted. The silica fibers contain 80% to 99.98% of silicon dioxide.

[0013] Tirone Cornbower, in the publication of the Mexican patent application MX-PA04009912, describes a laminated paper structure consisting of two outer layers and at least one inner layer. The outer layers are formed by substantially cellulose pulp and the inner layer of 60% to 80% by weight of cellulose pulp fiber with 5% to 15% by weight of a high temperature resistant fiber, for example, polyaramide fibers, and 10% to 25% of a polymeric binding agent, for example, of polyvinyl alcohol.

[0014] Junichi Hoshino and Kosaku Nagashima, in the publication of Japanese patent application JP-2006291383, describe a heat resistant and release paper made from a natural paper as a base paper, which is impregnated with an acrylic resin and coated on one of its surfaces with polyvinyl alcohol, and has a coating of a release agent.

[0015] In view of the above, it is therefore necessary to provide a paper that is heat resistant, resistant or impervious to liquids, grease or oil, resistant to cracking, and has release properties, which can be used as wrapping paper for food and which, therefore can be introduced, along with the wrapped food in any type of current oven without any risk of burning the paper, releasing residues, adhering to the food, cracking, or allowing the passage of liquids or greases released by the heated food, and further, is not unpleasant to sight and touch.

SUMMARY OF THE INVENTION

[0016] In view of the above, and with the object of finding solutions to the limitations encountered, it is the object of the invention to provide a heat, grease, and cracking resistant release paper, composed from 55% to 68% in weight of cellulose fiber, from 3% to 6% by weight of one or more sizing agents, from 27% to 37% by weight of one or more fillers, and from 1% to 3% by weight of one or more binding agents.

[0017] Another object of the invention is to provide a process for producing a heat, grease, and cracking resistant release paper, the process contains the steps of forming a paper pulp from a mixture from 55% to 68% by weight of cellulose fibers, from 6% to 7.5% by weight of one or more fillers, and from 0.03% to 0.05% by weight of one or more binding agents; reacting the paper pulp with from 1.5% to 2.4% by weight of one or more sizing agents, from 17% to 27% by weight of one or more fillers, and from 0.7% to 1.2% by weight of one or more binding agents; forming and drying a continuous sheet of paper from the paper pulp; and reacting the continuous sheet of paper with from 1.5% to 3.6% by weight of one or more sizing agents, from 2.5% to 4% by weight of one or more fillers, and from 0.27% to 1.75% by weight of one or more binding agents.

DETAILED DESCRIPTION OF THE INVENTION

[0018] The characteristic details of this invention are described in the following paragraphs, which have the objective of defining the invention, but without limiting its scope.

[0019] The composition of the paper according to the invention shows components that in turn may consist of multiple components. The components are described individually below, without necessarily being described in any order of importance.

Cellulose Fiber

[0020] The present invention includes cellulose fibers commonly referred to as wood pulp fibers, obtained from raw materials containing hardwood pulp, softwood pulp, or combinations thereof.

[0021] The terms "hardwood pulp" and "softwood pulp" refer to species of trees from which wood is obtained that serves as a raw material to make paper; so, the hardwood pulp is obtained mainly from trees of the gymnosperm species or conifers such as pine or fir, while the softwood pulp is obtained from trees of the angiosperm species or flowering trees such as oak, birch or maple. The fiber length of hardwood pulp ranges between 0.2 mm to 0.8 mm, and the fiber length of softwood pulp ranges between 0.8 mm to 4.5 mm. Furthermore, these terms also refer to the grade of hardness of the wood.

[0022] The cellulose fibers for the paper of this invention can be obtained from the raw material through numerous chemical processes, known in the state of the art to produce paper pulp, and this in turn can undergo a process of decoloring, if desired.

[0023] In the composition of the paper of this invention, the range of the cellulose fiber content is from 55% to 68% by weight, where the content of hardwood pulp in relation to the content of softwood pulp varies between 0% to 100%, and from 100% to 0% respectively. The preferred range of content of the softwood pulp is from 70% to 85%, and of the hardwood pulp is from 15% to 30%.

Sizing Agents

[0024] In order to increase the resistance to moisture absorption and the resistance to the passage of liquids, for example, water, oil or grease, as well as to obtain a smooth surface finish of the paper of the present invention, one or more sizing agents are incorporated, which are selected from and alkyl ketene dimer and derivatives, alkenyl succinic anhydride, calcium stearate, cellulose stearate, cellulose and combinations thereof.

[0025] In accordance with the stages of a paper making process of the prior art, an internal sizing of the paper of the invention can be performed during or after the stage of refining the paper pulp, by applying alkyl ketene dimer and derivatives, and alkenyl succinic anhydride, and a superficial sizing can be performed during a sizing stage by pressing, applying an alkyl ketene dimer and derivatives, alkenyl succinic anhydride, calcium stearate, cellulose stearate, and combinations thereof. For an effective sizing, it is convenient that the sizing agent is distributed evenly across the fibers of the paper pulp, which is recommended to prepare emulsions or dispersions containing an aqueous phase and finely divided particles of sizing agents dispersed in the same, and with the use of emulsion stabilizers. The emulsion stabilizers or binding agents commonly used to prepare such emulsions are, for example, starches and cationic polymers that are described below.

[0026] In an embodiment of the invention, one or more sizing agents are used from 3% to 6% by weight, and particularly from 2.5% to 5% by weight of alkyl ketene dimer and its derivatives, and from 0.5% to 1% by weight of calcium stearate.

Fillers

[0027] In order to increase the heat resistance of the paper of the present invention and serve as a sealant for the same, microparticles of fillers are incorporated, which are selected of calcium carbonate, granulated calcium carbonate, precipitated calcium carbonate, kaolin, titanium dioxide, rutile titanium dioxide, anatasic titanium dioxide, hydrated aluminum silicate, talc, and combinations thereof.

[0028] The calcium carbonate, granulated calcium carbonate and/or precipitated calcium carbonate are basically used to increase the resistance to heat of the paper of this invention; whereas the release property, the opacity, as well as the whiteness of the paper of this invention improves through the incorporation of the rutile titanium dioxide and/or anatasic titanium dioxide.

[0029] In a process for producing paper according to prior art, the fillers can be added during the preparation and refining of the paper pulp, as well as once the paper is made during the sizing stage by pressing.

[0030] In a preferred embodiment of the invention, one or more fillers from 27% to 37% by weight are used, and particularly from 26.8% to 36% by weight of calcium carbonate, and from 0.2% to 1% by weight of titanium dioxide.

Binding Agents

[0031] In order to increase the resistance of the paper of the invention and serve as a sealant against the passage of liquids through the same, one or more binding agents are incorporated, such as starch, cationic starch, cationic amylopectin starch, acetylated starch, ethylated starch, polyvinyl alcohol, carboxy-methyl cellulose, anionic polyacrylamide, cationic polyacrylamide, epichlorohydrin polyamine, polyvinyl acetate, polyacrylates, polyacrylic acid, polystyrene, amylopectin-2-hydroxy-3-(trimethylammonium) propyl ether chloride, and combinations thereof.

[0032] According to the invention, the use of cationic starch is preferred, in particular cationic amylopectine starch can be prepared from treating amylopectin starch with a cationic agent such as 3-chloro-2-hydroxypropyl (trimethylammonium) chloride, 2,3-epoxypropyl (trimethylammonium) chloride, or 2-chloro ethyl (trimethylammonium) chloride, obtaining, for example, amylopectin-2-hydroxy-3-(trimethylammonium) propyl ether chloride.

[0033] The cationic amylopectin starch can be added at any point in the process for producing the paper, for example, during or after the refining stage of the paper pulp. If necessary, in addition to the cationic amylopectin starch, cationic starch can also be added to the paper pulp.

[0034] The cationic starch can be made through chemical modification of the starch, or just by boiling the raw starch and adding a cationic polymer of low molecular weight before, during or after the boiling, for example, cationic polyacrylamide.

[0035] The starch, the cationic starch, the cationic amylopectine starch, acetylated starch, ethylated starch, and amylopectin-2-hydroxy-3-(trimethylammonium) propyl ether chloride are used as reinforcement supports.

[0036] On the one hand, epichlorohydrin polyamine resins, anionic polyacrylamide resins, and mixtures thereof act as binding agents to determine and uniformly deposit the fillers in the cellulose fiber, whereas the acetylated starch, ethylated starch, cellulose carboxymethyl resins, cationic polyacrylamide resins, polyvinyl alcohol resins, starch, cationic starch, cationic amylopectin starch, amylopectin-2-hydroxy-3-(trimethylammonium) propyl ether chloride, and mixtures thereof act as binding agents for resistance to the traction of the paper in the dry state, and in particular the amylopectin-2-hydroxy-3-(trimethylammonium) propyl ether chloride improves the resistance to tearing. Whereas on the other side, the sodium polyacrylate acts as a disperser.

[0037] In a preferred embodiment of the invention, one or more binding agents from 1% to 3% by weight are used, and particularly from 0.8% to 1.6% by weight of acetylated starch, from 0.1% to 0.4% by weight of anionic polyacrylamide, from 0.05% to 0.25% by weight of sodium polyacrylate, from 0.01% to 0.07% by weight of epichlorohydrin polyamine, from 0.3% to 0.6% by weight of cationic starch, and from 0.01% by weight to 0.07% by weight of amylopectin-2-hydroxy-3-(trimethylammonium) propyl ether chloride.

Composition of the Paper of the Invention

[0038] The paper producted according to this invention presents a composition from 55% to 68% by weight of cellulose fibers; from 3% to 6% by weight of one or more sizing agents; from 27% to 37% by weight of one or more fillers; and from 1% to 3% by weight of one or more binding agents.

[0039] Where the contents of the cellulose fiber, from 70% to 85% is softwood pulp and from 15% to 30% is hardwood pulp; the contents of the sizing agents, from 2.5% to 5% by weight is alkyl ketene dimer and its derivatives, and from 0.5% to 1% by weight is calcium stearate; the contents of the fillers is from 26.8% to 36% by weight is calcium carbonate, and from 0.2% to 1% by weight is titanium dioxide; and the content of the binding agents is from 0.8% to 1.6% by weight of acetylated starch, from 0.1% to 0.4% by weight of anionic polyacrylamide, from 0.05% to 0.25% by weight of sodium polyacrylate, from 0.01% to 0.07% by weight of epichlorohydrin polyamine, from 0.3% to 0.6% by weight of cationic starch, and from 0.01% to 0.07% by weight of amylopectin-2-hydroxy-3-(trimethylammonium) propyl ether chloride.

Process for Producing the Paper of the Invention

[0040] The heat, grease, and cracking resistant release paper of the invention, is produced from a paper pulp with a mixture from 55% to 68% by weight of cellulose fiber, whereas from 70% to 85% of the cellulose fiber is softwood pulp, and from 15% to 30% is hardwood pulp; from 6% to 7.5% by weight of one or more fillers, preferably calcium carbonate, and from 0.03% to 0.05% by weight one or more binding agents, preferably epichlorohydrin polyamine.

[0041] Then, during or after a stage of refining, the paper pulp reacts with from 1.5% to 2.4% by weight of one or more sizing agents, preferably alkyl ketene dimer; with from 17% to 27% by weight of one or more fillers, preferably granulated calcium carbonate; and with from 0.7% to 1.2% by weight of one or more binding agents, preferably from 0.35% to 0.57% by weight of cationic starch, from 0.24% to 0.37% by weight of anionic polyacrylamide, and from 0.11% to 0.17% by weight of sodium polyacrylate.

[0042] Subsequently, a continuous dry sheet of paper is formed, which is reacted with from 1.5% to 3.6% by weight of one or more sizing agents, preferably from 1% to 2% by weight of alkyl ketene dimer, and from 0.5% to 1.6% by weight of calcium stearate; with from 2.5% to 4% by weight of one or more fillers, preferably from 1.78% to 3.3% by weight of calcium carbonate and from 0.3% to 0.7% by weight of titanium dioxide; and with from 0.27% to 1.75% by weight of one or more binding agents, preferably from 0.25% to 1.7% by weight of acetylated starch and from 0.02% to 0.05% by weight of sodium polyacrylate.

Mechanical and Physical Properties of the Paper of the Invention

[0043] The produced paper according to the invention has the following physical and mechanical properties, shown in Table 1 according to standards and methods of the Technical Association of Pulp and Paper Industry known by its initials in English as TAPPI.

TABLE-US-00001 TABLE 1 TAPPI Property Unit Objective Minimum Maximum Method Base Weight g/m.sup.2 39 37 41 T-410 Humidity % 4.0 3.5 4.5 T-412 Thickness in .times. 10.sup.-3 2.3 2.1 2.5 T-411 Gurley Porosity sec 15 5 30 T-460 Whiteness % PH 89 86 -- T-452 Opacity % PH 78 74 -- T-425 Sizing COBB g/m.sup.2 12 10 14 T-441 Ashes % 20 17 23 T-413 Hue L L 95 93 97 T-524 Tone A a 1.0 0.0 2.0 T-524 Tone A b 0.0 -1.5 1.5 T-524 DM Tension kg/15 mm 2.0 1.6 -- T-404 DT Tension kg/15 mm 1.4 0.8 -- T-404 DM Tearing grams 12 10 -- T-414 DT Tearing grams 14 12 -- T-414 LF Sliding grades 27 25 30 T-548 LT Sliding grades 27 25 30 T-548 Clean S/M Good -- -- 6 Formation S/M Good -- -- Visual COF Radians Good -- 0.6 T-549

EXAMPLES OF EMBODIMENTS OF THE INVENTION

[0044] The invention will now be described in reference to the following examples, which is solely for the purpose of presenting the way of carrying out the implementation of the principles of the invention. The following examples are not intended to be a comprehensive presentation of the invention, nor try to limit the scope thereof.

Example 1

[0045] Paper pulp is prepared containing 655.50 kg of softwood pulp, 115.7 kg of hardwood pulp, 85 kg of calcium carbonate, and 0.5 kg of epichlorohydrin polyamine resin per ton of produced paper. Next, during of after the refining stage, this paper pulp is increased by 6 kg of cationic starch or amylopectin-2-hydroxy-3-(trimethylammonium) propyl ether chloride, 25 kg of alkyl ketene dimer, 4 kg of anionic polyacrylamide resin, 1.7 kg of sodium polyacrylate, and 286 kg of calcium carbonate per ton of produced paper. Once the continuous sheet of paper is produced, it is made to react by a sizing press with 0.3 kg of sodium polyacrylate, 16 kg of acetylated starch, 29 kg of sodium carbonate, 5 kg of rutile titanium dioxide, 10 kg of calcium stearate, and 20 kg of alkyl ketene dimer per ton of produced paper.

Example 2

[0046] The same preparation as in example 1, except that during the preparation of the paper pulp, 540 kg of softwood pulp and 231.35 kg of hardwood pulp are used per ton of produced paper.

Example 3

[0047] Paper pulp is prepared containing 775.16 kg of softwood pulp, 85 kg of calcium carbonate, and 0.5 kg of epichlorohydrin polyamine resin per ton of produced paper. Next, during of after a refining stage, this paper pulp is increased by 4.2 kg of cationic starch or amylopectin-2-hydroxy-3-(trimethylammonium) propyl ether chloride, 17.5 kg of alkyl ketene dimer, 2.8 kg of anionic polyacrylamide resin, 1.2 kg of sodium polyacrylate, and 220.2 kg of calcium carbonate per ton of produced paper. Once the continuous sheet of paper is produced, it is made to react by a sizing press with 0.2 kg of sodium polyacrylate, 11.2 kg of acetylated starch, 20.3 kg of sodium carbonate, 3.5 kg of rutile titanium dioxide, 7 kg of calcium stearate, and 24 kg of alkyl ketene dimer per ton of produced paper.

Example 4

[0048] A paper pulp is prepared containing 775.16 kg of softwood pulp, 85 kg of calcium carbonate, and 0.5 kg of epichlorohydrin polyamine resin per ton of produced paper. Later, during or after a refining stage, this paper pulp is increased with 7.8 kg of cationic starch or amylopectin-2-hydroxy-3-(trimethylammonium) propyl ether chloride, 32.5 kg of alkyl ketene dimer, 5.2 kg of anionic polyacrylamide resin, 2.2 kg of sodium polyacrylate, and 371.8 kg of calcium carbonate per ton of produced paper. Once the continuous sheet of paper is produced, it is made to react by a sizing press with 0.4 kg of sodium polyacrylate, 20.8 kg of acetylated starch, 37.7 kg of sodium carbonate, 6.5 kg of rutile titanium dioxide, 13 kg of calcium stearate, and 26 kg of alkyl ketene dimer per ton of produced paper.

Example 5

[0049] Paper pulp is prepared containing 775.16 kg of softwood pulp, 85 kg of calcium carbonate, and 0.5 kg of poliamin epichlorhydrine resin per ton of produced paper. Later, during or after a refining stage, this paper pulp is increased with 6 kg of cationic starch or amylopectin-2-hydroxy-3-(trimethylammonium) propyl ether chloride, 25 kg of alkyl ketene dimer, 4 kg of anionic polyacrylamide resin, 1.7 kg of sodium polyacrylate, and 286 kg of calcium carbonate per ton of produced paper. Once the continuous sheet of paper is produced, it is made to react by a sizing press with 0.3 kg of sodium polyacrylate, 16 kg of acetylated starch, 29 kg of sodium carbonate, 5 kg of rutile titanium dioxide, 10 kg of calcium stearate, and 20 kg of alkyl ketene dimer per ton of produced paper.

Example 6

[0050] The same preparation as in Example 5, except that it contains ethylated starch, not any other starch.

Example 7

[0051] Paper pulp is prepared containing 775.16 kg of softwood pulp, 85 kg of calcium carbonate, and 0.5 kg of epichlorhydrine poliamin resin per ton of produced paper. Next, during of after the refining stage, this paper pulp is increased by 6 kg of cationic starch or amylopectin-2-hydroxy-3-(trimethylammonium) propyl ether chloride, 25 kg of alkyl ketene dimer, 4 kg of anionic polyacrylamide resin, 1.7 kg of sodium polyacrylate, and 286 kg of calcium carbonate per ton of paper produced Once the continuous sheet of paper is produced, it is made to react by a sizing press with 0.3 kg of sodium polyacrylate, 16 kg of acetylated starch, 29 kg of sodium carbonate, 5 kg of rutile titanium dioxide, 10 kg of calcium stearate and 20 kg of alkyl ketene dimer per ton of produced paper.

Example 8

[0052] Paper pulp is prepared containing 775.16 kg of softwood pulp, 85 kg of calcium carbonate, and 0.5 kg of epichlorhydrine poliamin resin per ton of produced paper. Next, during of after the refining stage, this paper pulp is increased by 6 kg of cationic starch or amylopectin-2-hydroxy-3-(trimethylammonium) propyl ether chloride, 25 kg of alkyl ketene dimer, 4 kg of anionic polyacrylamide resin, 1.7 kg of sodium polyacrylate, and 286 kg of calcium carbonate per ton of paper produced. Once the continuous sheet of paper is produced, it is made to react by a sizing press with 0.3 kg of sodium polyacrylate, 16 kg of acetylated starch, 5 kg of rutile titanium dioxide, 10 kg of calcium stearate, and 20 kg of alkyl ketene dimer per ton of produced paper.

Example 9

[0053] Paper pulp is prepared containing 775.16 kg of softwood pulp, 85 kg of calcium carbonate, and 0.5 kg of epichlorhydrine poliamin resin per ton of produced paper. Next, during of after the refining stage, this paper pulp is increased by 6 kg of cationic starch or amylopectin-2-hydroxy-3-(trimethylammonium) propyl ether chloride, 25 kg of alkyl ketene dimer, 4 kg of anionic polyacrylamide resin, 1.7 kg of sodium polyacrylate, and 286 kg of calcium carbonate per ton of paper produced. Once the continuous sheet of paper is produced, it is made to react by a sizing press with 0.3 kg of sodium polyacrylate, 16 kg of acetylated starch, 29 kg of sodium carbonate, 5 kg of rutile titanium dioxide, 10 kg of calcium stearate, and 4 kg of alkenyl succinic anhydride per ton of produced paper.

Example 10

[0054] Paper pulp is prepared containing 775.16 kg of softwood pulp, 85 kg of calcium carbonate, and 0.5 kg of epichlorhydrine poliamin resin per ton of produced paper. Next, during of after the refining stage, this paper pulp is increased by 6 kg of cationic starch or amylopectin-2-hydroxy-3-(trimethylammonium) propyl ether chloride, 25 kg of alkyl ketene dimer, 4 kg of anionic polyacrylamide resin, 1.7 kg of sodium polyacrylate, and 286 kg of calcium carbonate per ton of produced paper. Once the continuous sheet of paper is produced, it is made to react by a sizing press with 0.3 kg of sodium polyacrylate, 16 kg of acetylated starch, 29 kg of sodium carbonate, 5 kg of rutile titanium dioxide, 10 kg of calcium stearate per ton of produced paper.

[0055] Four sample sheets from each of the examples 1 to 10 were submitted to physical tests to determine, through visual assessment, smell and touch, its heat resistance, grease resistance, resistance to cracking, and anti-adherent properties.

[0056] The tests consisted in placing in the center of sample sheet 1 a raw biscuit, in the center of sample sheet 2 a piece of 4 cm.times.4 cm of a conventional slice of yellow cheese, in the center of sample sheet 3 a piece of approximately 4.5 cm.times.2 cm of conventional slice of bacon, and nothing on sample 4. Each of the 4 samples for each of the examples 1 to 10 were placed on a plastic tray and introduced separately in a cooking oven by combination of hot air, microwave and infrared heating of the TurboChef.RTM. brand, model Tornado.RTM. manufactured by TurboChef Technologies, Inc. at a cooking temperature of about 260.degree. C. to 345.degree. C. for 20 seconds and that was previously started for three hours. Later, each sample is removed from the cooking oven, and then the samples 1, 2 and 3 are removed, the biscuit, yellow cheese and bacon respectively, and thus evaluate the degree of heat resistance, resistance to grease, resistance to cracking and release properties of each of the samples for each of the examples.

[0057] The results obtained from the former samples are shown in Table 2, with the value of the grade of resistance to heat, resistance to fat, resistance to cracking and release on a scale from 0 to 5, where:

For the Testing of Resistance to Fat and Release:

[0058] 0 means very bad, that is, grease passes completely through the paper and the cheese, bacon or biscuit sticks to said sample paper. [0059] 1 means bad, that is, grease passes through the paper and approximately 3/4 parts of the cheese, bacon or biscuit that was in contact with the paper, sticks to said sample paper. [0060] 2 means regular, that is, grease passes slightly through the paper and approximately 2/4 parts of the cheese, bacon or biscuit that was in contact with the paper, sticks to said sample paper. [0061] 3 means good, that is, a small spot of grease is observed on the paper, and small pieces of cheese, bacon or biscuit stick to said sample paper. [0062] 4 means very good, that is, a very small spot of grease is observed on the paper, and no residues of cheese, bacon or biscuit stick to said sample paper. [0063] 5 means very good, that is, a very small spot of grease is observed on the paper, and there are no residues of cheese, bacon or biscuit stuck to said sample paper.

For the Testing of Resistance to Heat:

[0063] [0064] 0 means very bad, that is, the entire sample paper is dark brown compared with a sample of the paper that was not submitted to the test. [0065] 1 means bad, that is, the sample paper surface is approximately 80% dark brown and the rest of its surface is light brown compared with a sample of the paper that was not submitted to the test. [0066] 2 means regular, that is, the sample paper surface is approximately 50% dark brown and the rest of its surface is light brown compared with a sample of the paper that was not submitted to the test. [0067] 3 means good, that is, the sample paper surface is approximately 30% light brown and the rest of its surface is yellowish compared with a sample of the paper that was not submitted to the test. [0068] 4 means very good, that is, the sample paper surface is approximately 20% yellowish and the rest of its surface is very light brown compared with a sample of the paper that was not submitted to the test. [0069] 5 means excellent, that is, the entire sample paper does not show any degradation in color compared with a sample of the paper that was not submitted to the test.

For the Testing of Resistance to Cracking:

[0069] [0070] 0 means very bad, that is, the entire sample paper is completely torn to pieces. [0071] 1 means very bad, that is, the sample paper is cracked over approximately 3/4 parts. [0072] 2 means regular, that is, the sample paper is slightly torn over approximately 2/4 parts. [0073] 3 means good, that is, the sample paper is only crumpled over approximately 3/4 parts, but this area is not cracked. [0074] 4 means very good, that is, the sample paper is only crumpled over approximately 2/4 parts, but this area is not cracked. [0075] 5 means excellent, ie the sample of paper slightly crumples and does not break.

TABLE-US-00002 [0075] TABLE 2 Sample 1 Test Example 1 Example 2 Example 3 Example 4 Example 5 Heat 4.5 4.5 4.5 5 4.5 resistance Grease 5 5 5 5 5 Resistance Release 4 4 4 4 4 Example 6 Example 7 Example 8 Example 9 Example 10 Heat 4.5 4.5 4.5 4.5 4.5 resistance Grease 5 5 5 5 5 Resistance Release 4 3.5 4 4 4 Sample 2 Test EXAMPLE 1 EXAMPLE 2 EXAMPLE 3 EXAMPLE 4 EXAMPLE 5 Heat 4 4.5 4.5 5 5 resistance Grease 4.5 3.5 4 4 4 Resistance Release 4 4.5 3.5 4.5 5 EXAMPLE 6 EXAMPLE 7 Example 8 Example 9 Example 10 Heat 4.5 4.5 5 5 4.5 resistance Grease 4 4 4 4.5 3.5 Resistance Release 5 4 4 4 3.5 Sample 3 Test Example 1 Example 2 Example 3 Example 4 Example 5 Heat 4.5 4.5 5 5 4.5 resistance Grease 4 5 4 4.5 4 Resistance Release 5 5 5 4.5 5 Example 6 Example 7 Example 8 Example 9 Example 10 Heat 5 5 5 5 5 resistance Grease 4.5 4.5 4 4.5 4 Resistance Release 4.5 4.5 4 4.5 5 Sample 4 Test Example 1 Example 2 Example 3 Example 4 Example 5 Heat 4.5 4.5 4.5 4.5 4 resistance Resistance to 5 5 4.5 4.5 5 cracking Example 6 Example 7 Example 8 Example 9 Example 10 Heat 4.5 4.0 4.5 4.0 3.5 resistance Resistance to 4.5 4.0 5.0 4.5 4.5 cracking

[0076] Finally, it must be understood that the heat, grease, and cracking resistant release paper, and the process for producing it according to the invention are not limited to the embodiments or modalities described above and before, and that the experts in the field will be trained by the training set established herein to perform changes in the composition of the paper and the conditions of the process of the present invention, whose scope will be established exclusively by the following claims:

Claims

1. A heat, grease, and cracking resistance release paper, which comprising: from 55% to 68% by weight of cellulose fiber; from 3% to 6% by weight of one or more sizing agents; from 27% to 37% by weight of one or more fillers; and from 1% to 3% by weight of one or more binding agents.

2. The paper of claim 1, wherein the cellulose fiber is selected from a group consisting of softwood pulp, hardwood pulp, and combinations thereof.

3. The paper of claim 2, wherein the cellulose fiber comprises: from 70% to 85% of softwood pulp; and from 15% to 30% of hardwood pulp.

4. The paper of claim 1, wherein the sizing agent is selected from a group consisting of alkyl ketene dimer and derivates, alkenyl succinic anhydride, calcium stereate, cellulose stereate, and combinations thereof.

5. The paper of claim 4, wherein the sizing agent includes: from 2.5% to 5% by weight of alkyl ketene dimer and derivatives; and from 0.5% to 1% by weight of calcium stereate.

6. The paper of claim 1, wherein the filler is selected from a group consisting of calcium carbonate, granulated calcium carbonate, precipitated calcium carbonate, kaolin, titanium dioxide, rutile titanium dioxide, anatasic titanium dioxide, hydrated aluminum silicate, talc, and combinations thereof.

7. The paper of claim 6, wherein the filler includes: from 26.8% to 36% by weight of calcium carbonate; and from 0.2% to 1% by weight of titanium dioxide.

8. The paper of claim 1, wherein the binding agent is selected from a group consisting of starch, cationic starch, cationic amylopectin starch, acetylated starch, ethylated starch, polyvinyl alcohol, carboxy-methyl cellulose, anionic polyacrylamide, cationic polyacrylamide, epichlorohydrin polyamine, polyvinyl acetate, polyacrylates, polyacrylic acid, polystyrene, amylopectin-2-hydroxy-3-(trimethylammonium) propyl ether chloride, and combinations thereof.

9. The paper of claim 8, wherein the binding agent includes: from 0.8% to 1.6% by weight of acetylated starch; from 0.1% to 0.4% by weight of anionic polyacrylamide; from 0.05% to 0.25% by weight of sodium polyacrylate; from 0.01% to 0.07% by weight of epichlorohydrin polyamine; from 0.3% to 0.6% by weight of starch cationic starch; and from 0.01% to 0.07% by weight of amylopectin-2-hydroxy-3-(trimethylammonium) propyl ether chloride.

10. A process for producing a heat, grease, and cracking resistance release paper, the process is characterized by including the steps of: forming a paper pulp starting out from a mixture of 55% to 68% by weight of cellulose fiber, from 6% to 7.5% by weight of one or more fillers, and from 0.03% to 0.05% by weight of one or more binding agents; reacting the paper pulp with from 1.5% to 2.4% by weight of one or more sizing agents, from 17% to 27% by weight of one or more fillers, and from 0.7% to 1.2% by weight of one or more binding agents; forming and drying a continuous sheet of paper from the paper pulp; and reacting the continuous sheet of paper with from 1.5% to 3.6% by weight of one or more sizing agents, from 2.5% to 4% by weight of one or more fillers, and from 0.27% to 1.75% by weight of one or more binding agents.

11. The process of claim 10, wherein the cellulose fiber is selected from a group consisting of hardwood pulp, softwood pulp, and combinations thereof.

12. The process of claim 11, wherein the cellulose fiber comprises: from 70% to 85% of softwood pulp; and from 15% to 30% of hardwood pulp.

13. The process of claim 10, wherein the sizing agent is selected from a group consisting of alkyl ketene dimer and derivatives, alkenyl succinic anhydride, calcium stereate, cellulose stereate, and combinations thereof.

14. The process of claim 10, wherein the filler is selected from a group consisting of calcium carbonate, granulated calcium carbonate, precipitated calcium carbonate, kaolin, titanium dioxide, rutile titanium dioxide, anatasic titanium dioxide, hydrated aluminum silicate, talc, and combinations thereof.

15. The process of claim 10, wherein the binding agent is selected from a group consisting of starch, cationic starch, cationic amylopectin starch, acetylated starch, ethylated starch, polyvinyl alcohol, carboxy-methyl cellulose, anionic polyacrylamide, cationic polyacrylamide, epichlorohydrin polyamine, polyvinyl acetate, polyacrylates, polyacrylic acid, polystyrene, amylopectin-2-hydroxy-3-(trimethylammonium) propyl ether chloride, and combinations thereof.

16. The process of claim 10, wherein the step of forming a paper pulp starting out from a mixture of 55% to 68% by weight of cellulose fiber, from 6% to 7.5% by weight of one or more fillers, and from 0.03% to 0.05% by weight of one or more binding agents; wherein said filler is granulated calcium carbonate and said binding agent is epichlorohydrin polyamine.

17. The process of claim 10, wherein the step of reacting the pulp with from 1.5% to 2.4% by weight of one or more sizing agents, from 17% to 27% by weight of one or more fillers, and from 0.7% to 1.2% by weight of one or more binding agents; wherein said sizing agent is alkyl ketene dimer, said filler is granulated calcium carbonate, and said binding agent is selected from a group consisting of cationic starch, anionic polyacrylamide, sodium polyacrylate, amylopectin-2-hydroxy-3-(trimethylammonium) propyl ether chloride, and combinations thereof.

18. The process of claim 17, wherein said binding agent includes: from 0.35% to 0.57% by weight of cationic starch; from 0.24% to 0.37% by weight of anionic polyacrylamide; and from 0.11% to 0.17% by weight of sodium polyacrylate.

19. The process of claim 10, wherein the step of reacting the continuous sheet of paper with from 1.5% to 3.6% by weight of one or more sizing agents, from 2.5% to 4% by weight of one or more fillers, and from 0.27% to 1.75% by weight of one or more binding agents; wherein said sizing agent is selected from a group consisting of alkyl ketene dimer, alkenyl succinic anhydride, calcium stereate, and combinations thereof; wherein said filler is selected from a group consisting of calcium carbonate, titanium dioxide, and combinations thereof; and wherein said binding agent is selected from a group consisting of acetylated starch, ethylated starch, sodium polyacrylate, and combinations thereof

20. The process of claim 19, wherein said sizing agent includes: from 1% to 2% by weight of alkyl ketene dimer; and from 0.5% to 1.6% by weight of calcium stereate.

21. The process of claim 19, wherein said filler includes: from 1.78% to 3.3% by weight of calcium carbonate; and from 0.3% to 0.7% by weight of titanium dioxide.

22. The process of claim 19, wherein said binding agent includes: from 0.25% to 1.7% by weight of acetylated starch; and from 0.02% to 0.05% by weight of sodium polyacrylate.