Oil-resistant agent for paper, oil-resistant paper, and method for producing same

Abstract

To provide an oil-resistant agent for non-fluorine-based paper, which can impart excellent oil resistance to a base material without using a fluorine-based compound, and can give oil-resistant paper excellent in oil resistance and high-temperature oil resistance in spite of a small environmental load, particularly when internally added to a paper base material in papermaking, pulp molding or the like.SOLUTION: An oil-resistant agent for paper, which is added to the inside of paper by an internal addition treatment, wherein the oil-resistant agent for paper contains quaternary cationized starch, and the quaternary cationized starch is a reaction product of starch and a quaternary ammonium compound having a glycidyl group or a derivative thereof, and satisfies the following condition 1 and / or condition 2: Condition 1: the quaternary cationized starch has a cationic charge amount of 160 to 470 μ eq / g. Condition 2: when the amount of the structure derived from starch in the quaternary cationized starch is 100 parts by mass, the amount of the structure derived from the quaternary ammonium compound or the derivative thereof is 1.2 to 9.0 parts by mass.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to an oil-proofing agent for paper, oil-proof paper obtained by using the same, and a method for producing the same. [Background technology]

[0002] In various fields such as textiles and paper, studies are being conducted to impart a stain-resistant function to substrates. Examples of stain-resistant functions include preventing the adhesion (penetration prevention) of aqueous stains by water repellency, preventing the adhesion (penetration prevention) of oily stains by oil repellency or oil resistance, and removing adhered stains by washing, etc.

[0003] Traditionally, compounds containing perfluoroalkyl groups have been used because they can impart excellent water repellency, oil repellency, and oil resistance. However, in recent years, the toxicity and environmental persistence of perfluorooctane sulfonic acid (PFOS) and perfluorooctanoic acid (PFOA) have become a concern, and the use of chemicals containing these compounds, as well as chemicals that may decompose and produce new compounds after being released into the environment, has been avoided. Furthermore, efforts are being made to replace these chemicals with chemicals composed of non-fluorinated compounds, which do not use fluorinated compounds themselves.

[0004] Of the antifouling functions, the oil repellency and oil resistance are largely dependent on the properties of the perfluoroalkyl group, and switching to non-fluorine-based agents has been difficult.

[0005] An example of an oil-resistant product for which such agents are used is oil-resistant paper, which is widely used as a material for packaging containers for detergents, confectioneries, dried foods, etc. It has a variety of uses, but paperboard that has been given oil resistance is often used as boxes for foods such as confectioneries, particularly boxes for chocolate confectioneries that contain a large amount of fat, while tissue paper that has been given oil resistance is often used as containers for packaging fried foods such as fast food, and packaging containers for takeout food at department stores, convenience stores, etc.

[0006] Examples of means for imparting oil resistance to paper include cooking sheets in which a fluorine-based oil-proofing agent is applied to the surface of paper or paperboard to form an oil-resistant layer, and oil-resistant paperboard for confectionery boxes in which a fluorine-based oil-proofing agent layer is provided between paper layers. However, it has been confirmed that paper using a fluorine-based oil-proofing agent generates fluorotelomer alcohols and the like when heated at food cooking temperatures of 100 to 180°C, and therefore there is a growing demand for oil-resistant paper that does not use a fluorine-based oil-proofing agent.

[0007] As grease-resistant papers that can be used as an alternative to fluorine-based grease-resistant agents, various types of grease-resistant papers have been disclosed, including those made by applying a non-fluorine-based acrylic resin grease-resistant agent to a paper base, those laminated with polyethylene film, those coated with polyethylene resin, and those using silicone-based or wax-based grease-resistant agents, as well as techniques for manufacturing such grease-resistant papers. However, each has its own advantages and disadvantages, and although some of these have been put to practical use, there is still a strong demand from users for improvements.

[0008] Incidentally, greaseproof paper using fluorine-based oil-proofing agents can achieve oil resistance with only a small amount of the agent, so the main methods used are to add the agent to the pulp slurry during the papermaking process or to attach it to the surface of the paper using a size press after papermaking.

[0009] On the other hand, when non-fluorinated compounds are used, they have poorer oil repellency than fluorinated compounds, and there is a problem that sufficient oil resistance cannot be achieved when using the internal addition method, in which a non-fluorinated compound is added to the pulp slurry during the papermaking process.

[0010] Furthermore, paper coated with non-fluorine-based acrylic resin and laminated paper use petroleum-derived chemical substances, and therefore, there is insufficient consideration given to the environmental impact.

[0011] For example, Patent Document 1 proposes a packaging material for food and the like, which is formed by papermaking a raw material liquid in which one or more of vegetable fiber, starch, and konjac paste are added to the main raw material pulp.

[0012] Furthermore, for example, Patent Document 2 proposes starch-processed paper (internal addition method) made of single-layer or multi-layer pulp material, in which starch is added to at least one layer of the pulp material in an amount ranging from 12.5 to 100% by weight of the total solid content of the paint.

[0013] Furthermore, Patent Document 3, for example, discloses a novel pulp molded product that has high gas barrier properties and excellent water and oil resistance. The pulp molded product contains pulp, a water- and oil-resistant agent, and a water-soluble polymer that is insoluble in aqueous media at 40°C or lower, and the content of the water-soluble polymer relative to the pulp is 1 to 50 mass%. In this product, a pulp-containing aqueous composition containing only powdered cationized starch as the water-soluble polymer in a pulp slurry is subjected to suction and dewatering through a pulp molding die and a reticulate body, and then dried at 60 to 200°C to obtain a pulp molded product (Comparative Examples 1 and 6).

[0014] However, the oil-resistant papers or molded products obtained by internally adding and coating or molding the oil-resistant agents disclosed in Patent Documents 1 to 3 still have insufficient oil resistance, and there are cases where sufficient performance is not achieved due to the influence of the paper base material manufacturing method (internal addition treatment during papermaking, internal addition treatment during pulp molding), etc., and these products have problems. [Prior art documents] [Patent documents]

[0015] [Patent Document 1] Japanese Patent Application Publication No. 7-145595 [Patent Document 2] Japanese Patent Application Laid-Open No. 2004-238518 [Patent Document 3] Japanese Patent Application Publication No. 2019-119938 Summary of the Invention [Problem to be solved by the invention]

[0016] The present invention aims to provide a non-fluorine-based oil-proofing agent for paper that can impart excellent oil resistance to a substrate without using a fluorine-based compound, and that, when internally added to a paper substrate in papermaking or pulp molding (hereinafter, these will also be referred to as "papermaking"), can produce grease-resistant paper that has excellent oil resistance and high-temperature oil resistance despite having a small environmental impact; and to provide grease-resistant paper obtained using the same and a method for producing the same. [Means for solving the problem]

[0017] As a result of extensive research to solve the above-mentioned problems, the present inventors have found that a paper oil-proofing agent used in applications such as papermaking and pulp molding, which is added to pulp slurry in internal addition treatments, contains a quaternary cationized starch, which is a reaction product of starch and a quaternary ammonium compound or a derivative thereof having a glycidyl group, and that by setting the cationic charge of the quaternary cationized starch to 160 to 470 μeq / g and / or setting the reaction amount of the quaternary ammonium compound or a derivative thereof relative to the starch to 1.2 to 9.0 parts by mass, it is possible to reduce the environmental load and impart excellent oil resistance to paper, even though it does not contain a fluorine-based compound. The present invention was completed based on this finding and through further extensive research, and it exhibits extremely excellent oil resistance even in pulp molded articles.

[0018] That is, the present invention provides the following configuration. Item 1. An oil-proofing agent for paper that is added to the inside of paper by internal addition treatment, The paper oil-proofing agent contains quaternary cationic starch, The quaternary cationized starch is a reaction product of starch with a quaternary ammonium compound having a glycidyl group or a derivative thereof, and is an oil-proofing agent for paper that satisfies the following condition 1 and / or condition 2: Condition 1: The cationic charge amount of the quaternary cationized starch is 160 to 470 μeq / g. Condition 2: When the amount of the structure derived from starch in the quaternary cationized starch is taken as 100 parts by mass, the amount of the structure derived from the quaternary ammonium compound or a derivative thereof is 1.2 to 9.0 parts by mass. Item 2. The quaternary ammonium compound having a glycidyl group is at least one selected from the group consisting of glycidyltrialkylammonium salts, glycidyldialkylbenzylammonium salts, glycidylalkyldibenzylammonium salts, glycidyltribenzylammonium salts, glycidyldialkylphenylammonium salts, glycidylalkyldiphenylammonium salts, glycidyltriphenylammonium salts, glycidyldialkylcycloalkylammonium salts, glycidylalkyldicycloalkylammonium salts, and glycidyltricycloalkylammonium salts, whose counter ions are not fluoride ions; The derivative of the quaternary ammonium compound having a glycidyl group may be selected from the group consisting of 3-chloro-2-hydroxypropyltrialkylammonium salts, 3-chloro-2-hydroxypropyldialkylbenzylammonium salts, 3-chloro-2-hydroxypropylalkyldibenzylammonium salts, 3-chloro-2-hydroxypropyltribenzylammonium salts, 3-chloro-2-hydroxypropyldialkylphenylammonium salts, 3-chloro-2-hydroxypropylalkyldiphenylammonium salts, 3-chloro-2-hydroxypropyltriphenylammonium salts, 3-chloro-2-hydroxypropyldialkylcycloalkylammonium salts, 3-chloro-2-hydroxypropylalkyldicycloalkylammonium salts, 3-chloro-2-hydroxypropyltricycloalkylammonium salts, 3-bromo-2-hydroxypropyltrialkylammonium salts, 3-bromo-2-hydroxypropyldialkylbenzylammonium salts, 3-bromo-2-hydroxypropylalkyldibenzylammonium salts, and 3-bromo-2-hydroxypropyltriphenylammonium salts. hydroxypropyltribenzylammonium salt, 3-bromo-2-hydroxypropyldialkylphenylammonium salt, 3-bromo-2-hydroxypropylalkyldiphenylammonium salt, 3-bromo-2-hydroxypropyltriphenylammonium salt, 3-bromo-2-hydroxypropyldialkylcycloalkylammonium salt, 3-bromo-2-hydroxypropylalkyldicycloalkylammonium salt, 3-bromo-2-hydroxypropyltricycloalkylammonium salt, 3-iodo-2-hydroxypropyltrialkylammonium salt, 3-iodo-2-hydroxypropyldialkylbenzylammonium salt, 3-iodo-2-hydroxypropylalkyldibenzylammonium salt, 3-iodo-2-hydroxypropyltribenzylammonium salt, 3-iodo-2-hydroxypropyldialkylphenylammonium salt, 3-iodo-2-hydroxypropylalkyldiphenylammonium salt, 3-iodo-2-hydroxypropyltriphenylammonium salt, 3-iodo-2-hydroxypropyldialkylcycloalkylammonium saltItem 1. The oil-proofing agent for paper according to Item 1, which is at least one selected from 3-iodo-2-hydroxypropylalkyldicycloalkylammonium salts and 3-iodo-2-hydroxypropyltricycloalkylammonium salts. Item 3. The grease-proofing agent for paper according to Item 2, wherein the quaternary ammonium compound having a glycidyl group or a derivative thereof is at least one selected from glycidyltrimethylammonium chloride, glycidyltrimethylammonium bromide, glycidyltrimethylammonium iodide, 3-chloro-2-hydroxypropyltrimethylammonium chloride, 3-chloro-2-hydroxypropyltrimethylammonium bromide, 3-chloro-2-hydroxypropyltrimethylammonium iodide, 3-bromo-2-hydroxypropyltrimethylammonium chloride, 3-bromo-2-hydroxypropyltrimethylammonium bromide, 3-bromo-2-hydroxypropyltrimethylammonium iodide, 3-iodo-2-hydroxypropyltrimethylammonium chloride, 3-iodo-2-hydroxypropyltrimethylammonium bromide, and 3-iodo-2-hydroxypropyltrimethylammonium iodide. Item 4. The oil-proofing agent for paper according to any one of Items 1 to 3, further comprising inorganic particles and / or a sizing agent. Item 5. The oil-proofing agent for paper according to any one of Items 1 to 4, which is added to the inside of paper used in food contact applications. Item 6. Grease-resistant paper containing the paper grease-proofing agent according to any one of items 1 to 5. Item 7. The greaseproof paper according to Item 6, wherein the content of the quaternary cationized starch is 3 to 80% by mass relative to the mass of the pulp. Item 8. The greaseproof paper according to Item 6 or 7, further containing inorganic particles and / or a sizing agent. Item 9. The greaseproof paper according to any one of Items 6 to 8, which is used in food contact applications. Item 10. Basis weight 50g / m 2 Item 10. The greaseproof paper according to any one of items 6 to 9. Item 11. The greaseproof paper according to any one of Items 6 to 10, which is a food packaging material or a food container. Item 12. The oil-resistant paper according to any one of items 6 to 11, which is evaluated as ○ or △ by the following oil resistance test method. [Oil resistance test method] The greaseproof paper is cut into a 4cm x 5cm rectangle. 75mg of soybean oil at room temperature (25°C) is dropped onto the surface of the greaseproof paper, and after leaving it at room temperature (25°C) for 30 minutes, the state of penetration of the soybean oil is visually observed and evaluated based on the following criteria. ○: No penetration is observed on the dropped surface of the greaseproof paper, or no penetration is observed when observing the greaseproof paper from the back side (no color change). △: When the greaseproof paper is observed from the back side, slight penetration is observed (slight color change). ×: When the greaseproof paper is observed from the back side, it is completely penetrated. Item 13. A method for producing greaseproof paper according to any one of items 6 to 12, A method for producing greaseproof paper, comprising the step of adding the quaternary cationized starch in the form of particles having an average particle size of 0.1 to 500 μm to a pulp slurry used in papermaking. Item 14. A method for producing greaseproof paper according to Item 13, further comprising adding inorganic particles and / or a sizing agent to the pulp slurry used in papermaking. [Effects of the Invention]

[0019] According to the present invention, it is possible to provide a non-fluorine-based oil-proofing agent for paper that can impart excellent oil resistance to a substrate without using a fluorine-based compound, and in particular, when the agent is internally added to a paper substrate during papermaking or pulp molding (hereinafter, these will also be referred to as "papermaking"), it is possible to obtain grease-resistant paper that has excellent oil resistance and high-temperature oil resistance despite having a small environmental impact, as well as grease-resistant paper obtained using the agent, and a method for producing the same. That is, by internally treating a paper substrate or a pulp molded article with the oil-proofing agent for paper of the present invention, excellent oil resistance can be imparted to the paper substrate or the pulp molded article without using a fluorine-based compound.Furthermore, good oil resistance against more practical high-temperature oils can also be imparted. Furthermore, since the present invention uses raw materials derived from starch, it is possible to use no petroleum-derived raw materials or to reduce the amount of petroleum-derived raw materials used, and is characterized by a small environmental impact. DETAILED DESCRIPTION OF THE INVENTION

[0020] <Starch> The paper grease-proofing agent of the present invention contains quaternary cationized starch. There are no particular limitations on the starch source for the cationized starch, and starches derived from plants such as cereals, tubers, roots, beans, and herbs can be used as appropriate. Examples of plant-derived starches include corn starch (such as corn starch, high-amylose corn starch, and waxy corn starch), wheat starch, rice starch, potato starch, sweet potato starch, tapioca starch, and sago starch.

[0021] Most types of starch are composed of granules in which two types of glucose polymers are present: amylose (15-35% by weight based on dry matter) and amylopectin (65-85% by weight based on dry matter). Amylose is composed of unbranched or slightly branched molecules with an average degree of polymerization of 1000-5000, depending on the type of starch. Amylopectin is composed of very large, highly branched molecules with an average degree of polymerization of 1,000,000 or more. The most important industrial starch types (corn starch, potato starch, wheat starch, and tapioca starch) contain 15-30% by weight of amylose.

[0022] Several types of cereals, such as barley, corn, millet, wheat, milo, rice, and sorghum, have subspecies whose starch granules are composed almost entirely of amylopectin. Calculated as a percentage by mass of dry matter, these starch granules contain more than 95% by mass, typically more than 98% by mass, of amylopectin. The amylose content of these cereal starch granules is therefore less than 5% by mass, typically less than 2% by mass. These cereal subspecies are also referred to as waxy cereal granules, and the amylopectin starch granules isolated from them are also referred to as waxy cereal starches.

[0023] In contrast to cereals, root and tuber subspecies whose starch granules are composed almost exclusively of amylopectin are virtually unknown. For example, potato starch granules isolated from potato tubers typically contain about 20% amylose and 80% amylopectin by weight (% by weight based on dry matter). However, there have been successful attempts to cultivate potato plants using genetic modification or genetic mutation to produce starch granules in potato tubers that are composed of more than 95% amylopectin by weight (based on dry matter). It has even been found feasible to produce potato tubers that contain essentially only amylopectin. It has also been found possible to cultivate and propagate other types of roots and tubers, such as yams or cassava, whose starch granules contain little or no amylose. As used herein, amylopectin starch is starch isolated from potato tubers and having an amylopectin content of at least 95% by weight, based on dry matter. Amylopectin starches are also called waxy starches, and these starches can also be used as raw materials.

[0024] Among the above starches, one or more selected from corn-derived starch, wheat starch, rice starch, potato starch, sweet potato starch, tapioca starch, and sago starch are preferred. These starches are preferably used in the form of fine powder (particles), and are preferably purified to remove as many impurities as possible before use.

[0025] <Quaternary ammonium compounds with glycidyl groups> In the present invention, a quaternary ammonium compound having a glycidyl group or a derivative thereof (hereinafter simply referred to as a "quaternary ammonium compound") is used as a starch cationizing agent.

[0026] Examples of the quaternary ammonium compound having a glycidyl group that can be used include glycidyltrialkylammonium salts, glycidyldialkylbenzylammonium salts, glycidylalkyldibenzylammonium salts, glycidyltribenzylammonium salts, glycidyldialkylphenylammonium salts, glycidylalkyldiphenylammonium salts, glycidyltriphenylammonium salts, glycidyldialkylcycloalkylammonium salts, glycidylalkyldicycloalkylammonium salts, and glycidyltricycloalkylammonium salts, all of which have a counter ion other than a fluoride ion.

[0027] Furthermore, examples of the derivatives of the quaternary ammonium compound having a glycidyl group include 3-chloro-2-hydroxypropyltrialkylammonium salts, 3-chloro-2-hydroxypropyldialkylbenzylammonium salts, 3-chloro-2-hydroxypropylalkyldibenzylammonium salts, 3-chloro-2-hydroxypropyltribenzylammonium salts, 3-chloro-2-hydroxypropyldialkylphenylammonium salts, 3-chloro-2-hydroxypropylalkyldiphenylammonium salts, 3-chloro-2-hydroxypropyltriphenylammonium salts, 3-chloro-2-hydroxypropyldialkylcycloalkylammonium salts, 3-chloro-2-hydroxypropylalkyldicycloalkylammonium salts, 3-chloro-2-hydroxypropyltricycloalkylammonium salts, 3-bromo-2-hydroxypropyltrialkylammonium salts, 3-bromo-2-hydroxypropyldialkylbenzylammonium salts, 3-bromo-2-hydroxypropylalkyldibenzylammonium salts, and 3-bromo-2-hydroxypropylalkyldibenzylammonium salts. iodo-2-hydroxypropyltribenzylammonium salt, 3-bromo-2-hydroxypropyldialkylphenylammonium salt, 3-bromo-2-hydroxypropylalkyldiphenylammonium salt, 3-bromo-2-hydroxypropyltriphenylammonium salt, 3-bromo-2-hydroxypropyldialkylcycloalkylammonium salt, 3-bromo-2-hydroxypropylalkyldicycloalkylammonium salt, 3-bromo-2-hydroxypropyltricycloalkylammonium salt, 3-iodo-2-hydroxypropyltrialkylammonium salt, 3-iodo-2-hydroxypropyldialkylbenzylammonium salt, 3-iodo-2-hydroxypropylalkyldibenzylammonium salt, 3-iodo-2-hydroxypropyltribenzylammonium salt, 3-iodo-2-hydroxypropyldialkylphenylammonium salt, 3-iodo-2-hydroxypropylalkyldiphenylammonium salt, 3-iodo-2-hydroxypropyltriphenylammonium salt, 3-iodo-2-hydroxypropyldialkylcycloalkylammonium saltExamples thereof include 3-iodo-2-hydroxypropyl alkyl dicycloalkyl ammonium salts and 3-iodo-2-hydroxypropyl tricycloalkyl ammonium salts, and these can be used alone or in combination of two or more.

[0028] In terms of oil resistance and safety, the quaternary ammonium compound is preferably glycidyltrimethylammonium chloride, glycidyltrimethylammonium bromide, glycidyltrimethylammonium iodide, 3-chloro-2-hydroxypropyltrimethylammonium chloride, 3-chloro-2-hydroxypropyltrimethylammonium bromide, 3-chloro-2-hydroxypropyltrimethylammonium iodide, 3-bromo-2-hydroxypropyltrimethylammonium chloride, 3-bromo-2-hydroxypropyltrimethylammonium bromide, 3-bromo-2-hydroxypropyltrimethylammonium iodide, 3-iodo-2-hydroxypropyltrimethylammonium chloride, 3-iodo-2-hydroxypropyltrimethylammonium bromide, or 3-iodo-2-hydroxypropyltrimethylammonium iodide, with glycidyltrimethylammonium chloride, glycidyltrimethylammonium bromide, or glycidyltrimethylammonium iodide being particularly preferred, and glycidyltrimethylammonium chloride being most preferred.

[0029] <Cationization treatment of starch> The quaternary cationized starch used in the present invention can be obtained by reacting raw starch with a quaternary ammonium compound having a glycidyl group or a derivative thereof using a known method. The method for cationizing starch is not particularly limited, but for example, the starch can be dissolved or dispersed in a medium such as water or an organic solvent and then subjected to cationization treatment. If necessary, a catalyst may be used, for example, amines or alkali metal hydroxides, such as sodium hydroxide or potassium hydroxide.

[0030] (Quaternary cationized starch) The quaternary cationized starch obtained as described above can be neutralized, washed and dried by conventional methods, if necessary. The quaternary cationized starch of the present invention is a compound containing a structure derived from at least either an amylose structure or an amylopectin structure, and is capable of exhibiting excellent oil resistance.

[0031] The paper greaseproofing agent of the present invention satisfies the following condition 1 and / or condition 2. In the present invention, excellent oil resistance can be exhibited when the paper greaseproofing agent simultaneously satisfies both condition 1 and condition 2, but excellent oil resistance can also be exhibited when the paper greaseproofing agent satisfies only condition 1 and does not satisfy or condition 2 is unknown. Furthermore, excellent oil resistance can also be exhibited when the paper greaseproofing agent satisfies only condition 2 and does not satisfy or condition 1 is unknown.

[0032] Condition 1 is that the cationic charge amount of the quaternary cationized starch measured by the following method is 160 to 470 μeq per 1 g of quaternary cationized starch (solid content). From the viewpoint of oil resistance, for condition 1, the cationic charge amount is preferably 170 to 460 μeq per 1 g of quaternary cationized starch (solid content), more preferably 180 to 440 μeq, even more preferably 185 to 420 μeq, particularly preferably 190 to 400 μeq, and extremely preferably 200 to 350 μeq.

[0033] The cationic charge can be adjusted by adjusting the amount of quaternary ammonium compound or its derivative added to the reaction mixture. If the cationic charge is less than 160 μeq per gram of quaternary cationized starch (solid content), oil will penetrate deeply into the thickness direction when grease-resistant paper is made, resulting in oil strike-through. The oil may also spread across the surface, resulting in bleeding and uneven printing. On the other hand, if the cationic charge is 160 μeq or more per gram of quaternary cationized starch (solid content), oil strike-through, bleeding, and uneven printing are suppressed. However, if the cationic charge is more than 470 μeq per gram of quaternary cationized starch (solid content), the oil resistance will be insufficient.

[0034] The cationic charge amount per gram of quaternary cationized starch (solid content) according to the present invention can be measured using a particle charge detector. While the measuring device and conditions may be changed as appropriate, the amount can be determined, for example, by the following method.

[0035] Quaternary cationized starch is added to distilled water and dissolved (gelatinized) at 80-90°C to prepare a 0.05 g / L aqueous solution. The solution is then cooled to 20°C and passed through a dedicated screen. 10 mL of the sample solution is titrated with an anionic titrant (Voyt Turbo, PES-Na / 0.001N) using a particle charge detector PCD-04 (Voyt Turbo) (drop rate: 0.001 mL every 15 seconds). The charge amount [μeq / L] is automatically calculated from the resulting anionic demand [mL], and converted to the cationic charge amount per gram of quaternary cationized starch (solid content) using the following formula:

[0036] Calculation formula: Cationic charge of quaternary cationized starch [μeq / g] = charge calculated from anionic demand [μeq / L] ÷ concentration of starch solution (g / L)

[0037] Furthermore, condition 2 is that, in the measurement method described below, when the amount of the structure derived from starch in the quaternary cationized starch is taken as 100 parts by mass, the amount of the structure derived from the quaternary ammonium compound or a derivative thereof (hereinafter also referred to as "cation structure amount") is 1.2 to 9.0 parts by mass. From the viewpoint of oil resistance, in condition 2, the amount of the cationic structure is preferably 1.5 to 8.0 parts by mass, more preferably 1.7 to 7.0 parts by mass, even more preferably 1.8 to 6.0 parts by mass, and particularly preferably 1.9 to 5.0 parts by mass.

[0038] The amount of structures derived from quaternary ammonium compounds or their derivatives can be adjusted mainly by adjusting the amount of quaternary ammonium compounds or their derivatives added to react with starch when obtaining quaternary cationized starch (cationization treatment). If the amount of the cationic structures is less than 1.2 parts by mass, when oil-resistant paper is made, oil will penetrate deeply in the thickness direction, causing oil strike-through, and the oil may also spread in the surface direction, resulting in bleeding and uneven printing. On the other hand, if the amount of the cationic structures is 1.2 parts by mass or more, the occurrence of oil strike-through, bleeding, and uneven printing is suppressed. However, if the amount of the cationic structures is more than 9.0 parts by mass, oil resistance will be insufficient.

[0039] <Measurement of the amount of structure derived from quaternary ammonium compounds or their derivatives> The amount of cationic structure can be measured by a known analytical method. For example, in the case of quaternary cationized starch obtained by reacting starch, glycidyl trimethylammonium chloride, and propylene oxide as reaction raw materials, 1H-NMR spectra (measurement solvent: deuterium oxide) were measured, and the molar ratios of the structures derived from each reactant were calculated from the peaks associated with the structures derived from each reactant. The measurement sample was prepared by adding quaternary cationized starch and deuterium oxide to an NMR sample tube, heating in boiling water until dissolved, and then allowing to cool before measurement. The molar ratios were calculated from the anomeric proton (1H) peak at approximately 5.4 ppm associated with the structure derived from starch, the methyl group proton (9H) peak at approximately 3.2 ppm associated with the structure derived from glycidyl trimethylammonium chloride, and the methyl group proton (3H) peak at approximately 1.1 ppm associated with the structure derived from propylene oxide, with the anomeric proton being set to 100. The mass ratios of the structures derived from the reactant materials were then calculated from the molecular weights of the reactant materials and the molar ratios, with the mass of starch being set to 100. The molecular weight of starch used was that of glucose.

[0040] In the present invention, the starch may be subjected to one or more known modification treatments in addition to the cationization treatment, as long as the desired performance is achieved. For example, modifications such as amphoterization, acid modification, enzyme modification, oxidation, roasted dextrinization, esterification, etherification, crosslinking, and grafting may be added.

[0041] For the oxidation treatment, an oxidizing agent such as hypochlorite can be used, and a carboxyl group, an aldehyde group, or a carbonyl group can be introduced. Examples of the esterification treatment include phosphate esterification, acetate esterification, succinate esterification, and octenyl succination. Examples of the etherification treatment include carboxymethylation, hydroxyethylation, and hydroxypropylation.

[0042] Examples of crosslinking treatments include phosphoric acid crosslinking, epichlorohydrin crosslinking, and adipic acid crosslinking.

[0043] Examples of amphoterization treatment include a method of introducing a betaine group and a method of performing a cationization treatment together with a treatment of introducing an anion group (for example, an oxidation treatment, a succinic acid esterification treatment, an octenyl succinate oxidation treatment, a carboxymethylation treatment, a phosphate esterification treatment, etc.).

[0044] In the grafting process, free radicals generated in starch act as initiators to react with radically polymerizable monomers to produce graft copolymers. Examples of radically polymerizable monomers include vinyl monomers, (meth)acrylate monomers, and (meth)acrylamide monomers. Examples include compounds obtained by saponifying a graft copolymer of acrylonitrile and starch with sodium hydroxide, and reaction products of starch with radically polymerizable monomers having long alkyl chains, such as stearyl acrylate and stearamidoethyl acrylate.

[0045] These modification treatments may be carried out to achieve any purpose, such as adjusting the gelatinization temperature of quaternary cationized starch, inhibiting retrogradation, adjusting hydrophilicity or hydrophobicity, adjusting solubility or dispersibility in a medium such as water, or improving printability.

[0046] The quaternary cationized starch used in the present invention is preferably used as the paper oil-proofing agent of the present invention itself and added in the form of particles (powder) to the pulp slurry used in papermaking. Alternatively, it may be added to the pulp slurry as a dispersion in a liquid medium. By adding the quaternary cationized starch in the form of particles (powder or dispersion), the quaternary cationized starch is more easily supported on the pulp during papermaking in the internal addition treatment. Conversely, if it is added as an aqueous solution, it is difficult to sufficiently support the quaternary cationized starch on the pulp.

[0047] Furthermore, quaternary cationized starch can be gelatinized at the raw material stage, during the modification process, or before use, and can be used in powder form. Oil resistance is achieved regardless of whether or not it is gelatinized, but gelatinization generally increases its affinity for water and makes it more likely to become powdery, so it must be thoroughly dispersed. From the standpoint of handling, it is preferable to use unegelatinized quaternary cationized starch.

[0048] <Method for measuring the average particle size of quaternary cationized starch> When quaternary cationized starch is added in powder form to the pulp slurry used for papermaking, a scanning electron microscope (SEM) photograph is taken of the powder at an appropriate magnification (e.g., 10 to 1000 times), the particle sizes of 100 particles are measured on the photograph, and the average value is calculated. When quaternary cationized starch is added in dispersion form to the pulp slurry used for papermaking, the water is removed from the aqueous dispersion of quaternary cationized starch by filtration. The water-wet product obtained as the filtration residue is dried under reduced pressure at room temperature. A scanning electron microscope (SEM) photograph is taken of the dried quaternary cationized starch at an appropriate magnification (10 to 1000 times), the particle sizes of 100 particles on the photograph are measured, and the average value is calculated.

[0049] When added to the pulp slurry, the quaternary cationized starch is preferably in a particulate state (powder or dispersed particles). The average particle size of the particulate quaternary cationized starch is not limited as long as the desired oil resistance is obtained, but is preferably in the range of 0.1 to 1000 μm, more preferably 0.5 to 500 μm, and even more preferably 1 to 200 μm, as calculated by the above-mentioned measurement method. If the average particle size of the particulate quaternary cationized starch is 0.1 μm or more, the quaternary cationized starch is easily supported on the pulp during papermaking, and if it is 1000 μm or less, the quaternary cationized starch can be prevented from falling off from the resulting greaseproof paper.

[0050] <Inorganic particles> In addition to the specific cationic starch, inorganic particles are preferably added to the oil-proofing agent for paper of the present invention. The inorganic particles are not particularly limited, and examples thereof include kaolin, clay, engineered kaolin, delaminated clay, calcined clay, heavy calcium carbonate, light calcium carbonate, talc, titanium dioxide, barium sulfate, calcium sulfate, zinc oxide, silicic acid, silicates, colloidal silica, and satin white. Their shape is not particularly limited, and may be, for example, spherical, plate-like, petal-like, or polyhedral. These particles may be used alone or in combination of two or more. The amount of inorganic particles added is not particularly limited, and may be added within a range that does not impair oil resistance, for example, to reduce costs and improve printability. For example, the amount is preferably 1 to 200 parts by weight, more preferably 5 to 100 parts by weight, even more preferably 10 to 80 parts by weight, and particularly preferably 20 to 60 parts by weight, per 100 parts by weight of quaternary cationized starch.

[0051] <Sizing agent> In addition to the specific cationic starch, a sizing agent is preferably added to the oil-proofing agent for paper of the present invention. When the paper greaseproofing agent of the present invention is used for internal addition in acidic papermaking, examples of the sizing agent include rosin-based sizing agents, rosin emulsion-based sizing agents, α-carboxymethyl saturated fatty acids, wax-based sizing agents, etc. When the paper greaseproofing agent of the present invention is used for internal addition in neutral papermaking, examples of the sizing agent include rosin-based sizing agents for neutral papermaking, alkyl ketene dimers, alkenyl succinic anhydrides, cationic polymer-based sizing agents, wax-based sizing agents, etc. The amount of sizing agent added is not particularly limited, but is, for example, 0.001 to 10.0 parts by mass per 100 parts by mass of pulp. Furthermore, a surface sizing agent (rosin-based sizing agent, synthetic resin-based sizing agent, wax-based sizing agent, etc.) can be added to the greaseproof paper by external addition using a size press or the like. In this application, unless there is a special reason, the sizing agent refers to a chemical that can impart water resistance to paper. For example, commercially available products can be used as these, and examples include sizing agents as well as hydrophobic agents such as water repellents, water-resistant agents, and waterproofing agents.

[0052] Since the oil-proofing agent for paper of the present invention can be easily added to the pulp slurry used in papermaking, it can also be in the form of being dispersed in a liquid medium such as water or an organic solvent.

[0053] In the present invention, examples of the liquid medium include water; aliphatic alcohols such as methanol, ethanol, isopropyl alcohol, isobutyl alcohol, hexyl alcohol, and 2-ethylhexyl alcohol; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, diisobutyl ketone, cyclohexanone, and diacetone alcohol; esters such as ethyl acetate, methyl acetate, butyl acetate, methyl lactate, and ethyl lactate; ethers such as diethyl ether, diisopropyl ether, methyl cellosolve, ethyl cellosolve, dioxane, and methyl tert-butyl ether; ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, and dipropylene glycol. Examples of suitable solvents include glycols such as ethylene glycol monobutyl ether, diethylene glycol monobutyl ether, diethylene glycol monomethyl ether, triethylene glycol monomethyl ether, propylene glycol monomethyl ether, and 3-methoxy-3-methyl-1-butanol; glycol esters such as ethylene glycol monomethyl ether acetate, propylene glycol monomethyl ether acetate, and diethylene glycol monoethyl ether acetate; and amides such as formamide, acetamide, benzamide, N,N-dimethylformamide, and acetanilide. These solvents may be used alone or in combination. While not particularly limited, water is preferred as the main solvent from the viewpoints of operational safety and environmental impact when added to the pulp slurry used in papermaking. When sufficient drying temperature and time cannot be achieved due to factors such as the specifications of the manufacturing equipment and damage to the substrate, a highly volatile organic solvent such as ethanol may also be used as the main solvent.

[0054] The quaternary cationized starch of the present invention can be dispersed in a medium by known methods, such as a method using a stirring blade or a method using a device such as a homomixer, a homogenizer, a high-pressure homogenizer, or an ultrasonic homogenizer. The quaternary cationized starch can be self-dispersed, but a surfactant may be added as a dispersant.

[0055] As the dispersant, known dispersants can be used, such as anionic surfactants, nonionic surfactants, cationic surfactants, and amphoteric surfactants. One type may be used alone, or two or more types may be used in combination.

[0056] Examples of anionic surfactants that can be used include various fatty acid salts, alkylbenzenesulfonates, alkanesulfonates, alkyl sulfates, alkyl phosphates, polyoxyethylene alkyl ether sulfates, polyoxyethylene-substituted phenyl ether sulfates, and polycarboxylates. Counterions include, but are not limited to, sodium, potassium, calcium, ammonium, and triethanolamine.

[0057] Examples of nonionic surfactants include, but are not limited to, various fatty acid esters such as glycerin, polyoxyethylene alkyl ethers, polyoxypropylene alkyl ethers, polyoxyethylene fatty acid esters, fatty acid alkanolamides, alkyl glucosides, higher alcohols, and pluronic emulsifiers.

[0058] Examples of cationic surfactants that can be used include quaternary salts such as various alkyltrimethylammonium salts, alkyldimethylbenzylammonium salts, dialkyldimethylammonium salts, alkylpyridinium chloride salts, and quaternized polyoxyethylene alkylamines, as well as amine salts obtained by neutralizing an amine with an appropriate acid, such as alkylamine salts, alkyldimethylamine salts, and polyoxyethylene alkylamine salts. Counter ions include, but are not limited to, chloride ions, bromide ions, sulfate ions, formate ions, acetate ions, methyl sulfate ions, and ethyl sulfate ions.

[0059] Examples of amphoteric surfactants include, but are not limited to, alkylbetaine-type amphoteric surfactants, amidobetaine-type amphoteric surfactants, sulfobetaine-type amphoteric surfactants, phosphobetaine-type amphoteric surfactants, imidazolinium betaine-type amphoteric surfactants, alkylamine oxide-type amphoteric surfactants, amino acid-type amphoteric surfactants, and phosphate ester-type amphoteric surfactants.

[0060] The amount of the oil-proofing agent for paper of the present invention added to the pulp slurry used in papermaking is preferably 10 to 200 parts by mass of quaternary cationized starch per 100 parts by mass of pulp in the pulp slurry. From the viewpoint of oil resistance, the amount of quaternary cationized starch added is more preferably 15 to 150 parts by mass, even more preferably 20 to 100 parts by mass, and particularly preferably 30 to 80 parts by mass from the viewpoints of oil resistance and cost.

[0061] In addition to the inorganic particles, sizing agent, liquid medium, and dispersant, other additives may be added to the oil-proofing agent for paper of the present invention as needed, and the amount of addition may be appropriately determined taking oil resistance into consideration. Examples of additives include other oil-proofing agents, water-repellent agents, paper strength agents, penetrating agents, antifoaming agents, pH adjusters, antibacterial agents, antifungal agents, colorants, antioxidants, deodorizers, fillers, chelating agents, antistatic agents, catalysts, crosslinking agents, antibacterial and deodorizing agents, flame retardants, softeners, wrinkle-proofing agents, and fixing agents (aluminum sulfate, polyaluminum chloride, etc.).

[0062] Examples of the defoaming agent include oil-based defoaming agents such as castor oil, sesame oil, linseed oil, and animal and vegetable oils; fatty acid-based defoaming agents such as stearic acid, oleic acid, and palmitic acid; fatty acid ester-based defoaming agents such as isoamyl stearate, distearyl succinate, ethylene glycol distearate, and butyl stearate; alcohol-based defoaming agents such as polyoxyalkylene monohydric alcohol di-t-amylphenoxyethanol, 3-heptanol, and 2-ethylhexanol; ether-based defoaming agents such as di-t-amylphenoxyethanol 3-heptylcellosolve nonylcellosolve 3-heptylcarbitol; phosphate ester-based defoaming agents such as tributyl phosphate and tris(butoxyethyl)phosphate; amine-based defoaming agents such as diamylamine; amide-based defoaming agents such as polyalkylene amides and acylate polyamines; sulfate ester-based defoaming agents such as sodium lauryl sulfate; and mineral oil. The antifoaming agents can be used alone or in combination of two or more.

[0063] It is preferable to use an antistatic agent that does not easily impair oil resistance. Examples of antistatic agents include anionic antistatic agents such as higher alcohol sulfate salts, sulfated oils, and sulfonates; cationic antistatic agents such as quaternary ammonium salts and imidazoline-type quaternary salts; nonionic antistatic agents such as polyethylene glycol-type and polyhydric alcohol ester-type; amphoteric antistatic agents such as imidazoline-type quaternary salts, alanine-type and betaine-type; high-molecular compound-type antistatic polymers; and polyalkylamines. Antistatic agents can be used alone or in combination of two or more.

[0064] The greaseproof paper of the present invention is paper containing the greaseproofing agent for paper of the present invention therein. As a method for producing greaseproof paper by previously mixing the greaseproofing agent for paper of the present invention with pulp, there is a method called "internal addition treatment" in which a pulp slurry containing the greaseproofing agent for paper is made into paper or molded into pulp. In the present invention, it is preferable to produce greaseproof paper by internal addition treatment.

[0065] In the internal addition treatment, a paper grease-proofing agent is mixed with a pulp slurry and then paper is produced, thereby producing paper in which the grease-proofing agent is added to the inside of the paper. Paper in which the grease-proofing agent is added to the inside of the paper is greaseproof paper, which has oil resistance. The greaseproof paper may be thin paper, thick paper, or pulp-molded paper, as long as it has oil resistance.

[0066] There are no particular restrictions on the basis weight of the pulp (see the item on [Basis Weight] of the test paper using only pulp, which will be described later). For example, from the viewpoint of oil resistance, the basis weight of the pulp should be 50 g / m 2 It is sufficient if the thickness is equal to or greater than 70 g / m. 2 More preferably, 80 g / m 2 More preferably, 100 g / m 2 More preferably, 150 g / m 2 More than 180g / m 2 The above is extremely preferable, and oil resistance becomes good.

[0067] The basis weight of the greaseproof paper is not particularly limited. For example, from the viewpoint of oil resistance, the basis weight of the greaseproof paper is set to 50 g / m. 2 It is sufficient if the thickness is 90 g / m or more. 2 More preferably, 100 g / m 2 More preferably, 130 g / m 2 More preferably, 150 g / m 2 More than 200g / m 2 The above is extremely preferable, and oil resistance becomes good.

[0068] In the case of a molded container, the thickness is often not uniform and it may be difficult to measure the basis weight. However, if the basis weight of the localized portion where oil resistance is required is within the above range, it can be said that the container has excellent oil resistance.

[0069] The upper limit of the basis weight is not particularly limited and may be set appropriately depending on the intended use. For example, 2 The following is the result.

[0070] The components that make up greaseproof paper can be calculated from the amounts of pulp and additives used. For example, the amount of starch or sizing agent attached can be calculated by extracting and separating it from the greaseproof paper with water or an organic solvent, and in the case of inorganic particles, it can be calculated from the amount of ash by referring to methods such as Paper, Paperboard and Pulp - Ash Content Test Method - 525°C Combustion Method (JIS P 8251:2003).

[0071] <Oil-resistant paper manufacturing> Oil-resistant paper can be produced by forming a pulp slurry from raw pulp using a liquid medium such as water or the organic solvent, then adding the oil-proofing agent of the present invention to the slurry, and then carrying out papermaking or pulp molding by a known method, such as a method of making paper using a paper machine and then cylinder drying.

[0072] During the internal addition treatment, in addition to the oil-resistant agent of the present invention, other materials such as various internal addition aids can be added.

[0073] When the oil-proofing agent of the present invention is added, the stirring time or the liquid temperature may be adjusted so that the quaternary cationized starch is less likely to dissolve in the liquid medium, for example, by shortening the stirring time or lowering the liquid temperature.

[0074] When a plurality of chemicals are used in the internal addition treatment, they may be added in any order as long as the effects of the present invention are exhibited.

[0075] The greaseproof paper may be further subjected to various processes such as coating, printing, punching, gluing, box making, etc. to optimize it for actual uses (food contact uses) such as food packaging material and food containers.

[0076] <Raw pulp> In the present invention, the raw material pulp contains at least one type of pulp selected from wood pulp and non-wood pulp.

[0077] Wood pulp includes wood pulp generally used in papermaking, and depending on the preparation method, it can be classified into chemical pulps such as kraft pulp (KP), sulfite pulp (SP), and soda pulp (AP); semi-chemical pulps such as semi-chemical pulp (SCP) and chemi-ground wood pulp (CGP); mechanical pulps such as groundwood pulp (GP), thermomechanical pulp (TMP, BCTMP), and refiner ground wood pulp (RGP); and recycled paper pulp.

[0078] Examples of wood pulp include softwood pulp and hardwood pulp, depending on the raw material. Softwood pulp includes pulp obtained from the fir and pine genera. Hardwood pulp includes pulp obtained from the acacia, eucalyptus, beech, and poplar (e.g., poplar). Among these, softwood kraft pulp (NKP) and hardwood kraft pulp (LKP) are more preferred as wood pulp.

[0079] Non-wood pulp is fiber extracted from the bark, stems, leaves, and leaf sheaths of plants. Examples include pulp obtained from cotton linters, cotton, linen, hemp, ramie, straw, esparto, Manila hemp, sisal, jute, flax, kenaf, bamboo, bagasse, ganpi, mitsumata, mulberry, and mulberry. Bamboo and bagasse are preferably used in terms of ease of handling and supply.

[0080] In the present invention, as described above, wood pulp, non-wood pulp, or a mixture thereof can be used as the pulp raw material. While recycled paper such as recycled paper and recycled corrugated paper may be used as the pulp raw material, a high recycled paper content can result in problems such as poor surface smoothness and surface design due to the fibers of the recycled paper becoming fuzzy and deformed. From the viewpoint of improving the surface smoothness and surface design of the pulp molded body, the recycled paper content in the raw pulp is preferably 20% by mass or less, more preferably 10% by mass or less, even more preferably 3% by mass or less, and even more preferably no recycled paper is used.

[0081] The pulp used in the present invention may be adjusted for freeness (degree of beating) after disintegration, which can be measured, for example, by the Canadian Standard Freeness Method. From the viewpoints of productivity of the pulp raw material and papermaking properties, the Canadian Standard Freeness is preferably 100 mL or more, more preferably 150 mL or more, and even more preferably 200 mL or more, and from the viewpoint of surface smoothness, it is preferably 800 mL or less, more preferably 700 mL or less, and even more preferably 600 mL or less. The degree of beating may be adjusted so that the Canadian standard freeness falls within the above range. Canadian Standard Freeness is measured in accordance with JIS P 8121-2:2012.

[0082] <Internal additives, etc.> Examples of internal additives include sizing agents, inorganic particles such as talc and kaolin, inorganic fibers such as glass fiber and carbon fiber, powders or fibers of synthetic resins such as polyolefin, polysaccharides such as carboxymethyl cellulose, wet strength agents, oil-resistant agents, retention aids, drainage aids, bulking agents, aluminum sulfate, pH adjusters, pitch control agents, slime control agents, colorants such as pigments, etc. Among these, it is preferable to contain inorganic particles such as calcium carbonate and sizing agents.

[0083] As the sizing agent, known sizing agents can be used, for example, rosin-based, alkyl ketene dimer-based, alkenyl succinic anhydride-based, styrene-containing polymer-based such as styrene-(meth)acrylate copolymer, and wax-based such as paraffin, and rosin-based, alkyl ketene dimer-based, and wax-based agents are preferred. Rosin-based, alkyl ketene dimer-based and wax-based materials are particularly preferred because they are more likely to provide resistance to hot water.

[0084] Examples of wet strength agents for internal use include polyamidoamine-epichlorohydrin resin, epoxidized polyamidopolyamine, dialdehyde starch, urea-formaldehyde resin, melamine-formaldehyde, polyacrylamide, methylolated polyacrylamide, and polyethyleneimine.

[0085] Examples of water repellents include wax-based, metal soap-based (alkali salts of sodium, potassium, zinc, lithium, magnesium, etc.), fatty acid chromium complex salts (myristyl complex salts, stearic acid chromic chloride complex salts, etc.), zirconium-based, silicone-based, (meth)acrylic polymer-based, urethane dendrimer-based, and urethane polymer-based agents.

[0086] The oil-resistant paper of the present invention contains a specific quaternary cationic starch in the pulp raw material, which allows it to have sufficient oil resistance. However, this does not exclude the addition of a wet strength agent, a water repellent, or an oil-resistant agent to achieve even higher oil resistance and water resistance.

[0087] [Manufacturing method of pulp molded body] The method for producing the pulp molded body is not particularly limited, but it is preferable to produce it by a production method including the following steps 1 to 3 in this order. Step 1: Pulp suspension preparation step of preparing pulp slurry Process 2: The papermaking process in which pulp is made from the pulp slurry through a papermaking mold. Step 3: A hot pressing step in which the mold intermediate obtained after the paper-making step is hot-pressed using a first press die and a second press die positioned in the opposite direction to the first press die while heating the mold intermediate.

[0088] In step 1, a pulp slurry is prepared by adding a pulp raw material, the grease-proofing agent for paper of the present invention containing quaternary cationized starch, and other additives such as a sizing agent. The concentration of the slurry can be appropriately selected as needed, and from the viewpoints of surface smoothness, dimensional stability, and productivity, it is preferably 0.1% by mass or more, more preferably 0.3% by mass or more, and even more preferably 0.5% by mass or more, and is preferably 7% by mass or less, more preferably 5% by mass or less, and even more preferably 3% by mass or less.

[0089] Step 2 is a papermaking step in which pulp is made from the pulp slurry through a papermaking mold. A forming mold, such as a wire mesh mold with a vacuum-drawn water-permeable structure, is immersed in the pulp slurry, and the pulp slurry is sucked into the forming mold to drain the water, while the pulp fibers are stacked and adsorbed onto the mold to form a three-dimensional wet paper that is symmetrical to the mold.The forming mold is then lifted out of the pulp slurry, and the water-soaked three-dimensional wet paper is subjected to suction dewatering or pressure dewatering. At this time, the molding die with the pulp stacked and adsorbed onto its surface continues to be vacuum suctioned, and a release die (mold release device) with vacuum suction is brought close to face the pulp adsorption surface, and the pulp mold intermediate is dehydrated by compressed vacuum suction, after which the vacuum pressure of the molding die is reduced to zero, and the release die is pulled back with the pulp mold intermediate still adsorbed to the release die to release it.

[0090] Step 3 is a hot pressing step in which the mold intermediate obtained after the paper-making step is hot-pressed using a first press die and a second press die positioned in the opposite direction from the first press die while being heated. In step 3, the dehydrated pulp mold intermediate obtained in step 2 is transferred to, for example, a first press die for hot pressing, which is made of a porous die. The pulp mold intermediate transferred to the first press die is heated and pressurized by the first press die and a second press die for hot pressing, which is positioned in the opposite direction from the first press die and engages with the first press die, to obtain a predetermined pulp molded product.

[0091] It is preferable to incorporate an electric heater into at least one of the first and second press dies for hot pressing, thereby heating at least one of the first and second press dies. Alternatively, the entire die set including the first and second press dies may be housed in a furnace through which hot air is introduced, allowing hot air to pass through the interior of the dies.

[0092] In step 3 (hot pressing step), the pressure during pressing with the first press die and the second press die is not particularly limited as long as the desired pulp molded body can be obtained. For example, from the viewpoint of oil resistance, the pressure is 0.01 MPa or more, more preferably 0.05 MPa or more, even more preferably 0.1 MPa or more, and particularly preferably 0.15 MPa or more, and from the viewpoint of power consumption and equipment load, the pressure is preferably 3.0 MPa or less, more preferably 2.0 MPa or less, and even more preferably 1.5 MPa or less.

[0093] In step 3 (hot pressing step), the temperature during hot pressing is preferably 130°C or higher, more preferably 150°C or higher, and even more preferably 170°C or higher, from the viewpoint of obtaining a pulp molded body with excellent surface smoothness, and is preferably 280°C or lower, more preferably 250°C or lower, and even more preferably 230°C or lower, from the viewpoint of power consumption, equipment load, and suppression of discoloration.

[0094] The pulp molded article obtained as described above may be further processed by cutting off unnecessary portions and, if necessary, punching holes. Taking advantage of its excellent oil resistance and surface smoothness, the pulp molded article of this embodiment can be suitably used as a packaging material for foods, medical products, electronic components, etc. Furthermore, because its excellent surface smoothness makes it easy to perform processes such as printing, coating, and lamination on the surface, it is not limited to the above uses and can be widely used for small item containers, cup lids, ornaments, etc.

[0095] The present invention will be explained below by way of Production Examples and Examples, but the present invention is not limited to these Production Examples and Examples. In the examples, "parts" and "%" refer to "parts by mass" and "% by mass" unless otherwise specified. [Example]

[0096] The following examples will be specifically described, focusing on greaseproof paper produced using the greaseproofing agent for paper of the present invention, but the present invention is not limited to these examples. Furthermore, "parts" and "%" in the examples represent "parts by mass" and "% by mass" unless otherwise specified.

[0097] [Manufacturing example]

[0098] <Quaternary cationized starch> Starch, glycidyltrimethylammonium chloride (GTMAC), and propylene oxide (PO) were reacted to obtain the quaternary cationized starches (starches A to G) shown in Table 1.

[0099] Regarding the molar ratio of the structures derived from the reaction raw materials in Table 1, 1 The molar ratios of the reactants were calculated from the peaks associated with the structures derived from each reactant in the H-NMR spectrum (measurement solvent: deuterium oxide). The measurement sample was prepared by adding quaternary cationized starch and deuterium oxide to an NMR sample tube, heating in boiling water until dissolved, and then allowing to cool before measurement. The molar ratios were calculated from the anomeric proton (1H) peak at approximately 5.4 ppm associated with the structure derived from starch, the methyl group proton (9H) peak at approximately 3.2 ppm associated with the structure derived from glycidyl trimethylammonium chloride, and the methyl group proton (3H) peak at approximately 1.1 ppm associated with the structure derived from propylene oxide. The anomeric protons are set at 100 and are listed in the table.

[0100] The mass ratios of the structures derived from the reaction raw materials in Table 1 were calculated from the molecular weights of the reaction raw materials and the above-mentioned molar ratios, and are shown in the table with the mass of starch set to 100. The calculations for starch were performed using the molecular weight of glucose. The cationic charge amount [μeq / g] of the quaternary cationized starch in Table 1 was calculated according to the method described above.

[0101] The particle diameters of the quaternary cationized starches in Table 2 were measured from SEM images using a scanning electron microscope (SEM: Neo Scope JCM-7000, manufactured by JEOL Ltd.). 100 particles were randomly selected, and the minimum, maximum, and average particle diameters were calculated. When particles had irregular shapes, the particle diameter was determined as the longest part of the particle.

[0102] <Gelatinized quaternary cationized starch> Starch A was added to water and dissolved (gelatinized) at approximately 90°C. The resulting 5% aqueous solution was transferred to a tray and dried in a hot air dryer at 110°C to obtain a film-like dried product. This was then powdered using a MILLSER IFM-77G (manufactured by Iwatani Corporation) (Starch A').

[0103] [Table 1]

[0104] The value of "GTMAC" in the "mass ratio of structures derived from reaction raw materials" in Table 1 corresponds to the above-mentioned condition 2.

[0105] [Table 2]

[0106] [pulp] Bagasse (derived from sugarcane), LBKP (derived from broad-leaved trees, indicated as L in the table), or NBKP (derived from coniferous trees, indicated as N in the table) was used.

[0107] [Freeness] Measurements were carried out based on the Canadian Standard Freeness Method.

[0108] [Basic weight] The test paper was cut into a 10cm x 10cm square, and the freeness was calculated from its mass and area. The basis weight listed for the processing conditions in the table is a theoretical value obtained from the pulp used. Since fine fibers may pass through the screen, the value may be smaller than the theoretical value. In addition, the basis weight of the test paper for the pulp alone was used as the blank (BL) for each freeness.

[0109] [Basis weight - theoretical value] The values ​​were calculated assuming that all of the pulp, starch, and other chemicals had been converted into oil-resistant paper.

[0110] [Differences from BL] The increase in basis weight was calculated from the difference between the blank and the pulp slurry of the same freeness. The increase was assumed to be the amount of added chemicals attached to the test paper.

[0111] [Starch added amount] The value was calculated as the value when all of the added material adhered to the test paper.

[0112] [Yield rate] The retention rate of the added starch was calculated using the following formula. Yield rate (%) = difference from BL ÷ amount of starch added × 100

[0113] [Starch adhesion amount] Using the same freeness results, the adhesion amount of the added starch was calculated according to the following formula. Starch adhesion amount (mass%) = difference from BL ÷ BL basis weight × 100 When a drug other than starch was used in combination, the ratio of starch was calculated from the amount (mass ratio) of each drug added, and the calculated value is shown in the table.

[0114] [Oil resistance test method] The test paper was cut into a 4 cm x 5 cm rectangle. 75 mg of soybean oil (manufactured by Nacalai Tesque) heated to the temperature shown in the table was dropped onto the surface of the test paper, and the paper was then placed in a hot air dryer set to the same temperature as the dropped soybean oil. Note that the room temperature evaluation was performed without using a hot air dryer. After 30 minutes, the penetration of the soybean oil was visually observed and evaluated based on the following criteria.

[0115] This evaluation method is intended to evaluate the oil resistance required for molded containers. A rating of ○ or △ indicates that the product is at a level that presents no problems in terms of practical use. Since the required temperature conditions vary depending on the application, if oil resistance is obtained at least at room temperature, the product is deemed to be practical. Furthermore, when it is not possible to cut the test paper when evaluating a molded container, the oil can be poured directly into the container and evaluated in the same manner as described below. ○: No penetration is observed on the dropped surface of the greaseproof paper, or no penetration is observed when observing from the back side of the greaseproof paper (no color change). △: When observed from the back of the greaseproof paper, slight penetration is observed (slight color change). ×: When observed from the back side of the greaseproof paper, the ink has completely penetrated.

[0116] <Water resistance> The greaseproof paper of the present invention was cut into a 4 cm x 5 cm rectangle to prepare a sample. The sample was floated in water at room temperature and left to stand for 30 minutes, after which the water resistance was evaluated according to the following evaluation criteria. The test specimen was then placed in boiling water and left to stand for 30 minutes, after which the water resistance was evaluated in the same manner. After the test, the boiling water was allowed to cool and then heated to 60°C or higher using an induction heater. ○: No penetration is observed on the contact surface between the greaseproof paper and water, or no penetration is observed when observed from the opposite side (no color change). △: When observed from the opposite side of the greaseproof paper, slight penetration is observed (slight color change). ×: When observed from the opposite side of the greaseproof paper, the ink has completely penetrated.

[0117] Example 1 Commercially available bagasse was mixed with water to a pulp concentration of 2.25% by mass, and a pulp slurry was produced using a laboratory disintegrator (3000 rpm, 5 minutes). The freeness was 420 mL. The mixture was diluted with water to a pulp concentration of 1% by mass, and starch A was added in powder form to a concentration of 40% by mass relative to the pulp (solid content), followed by stirring for 1 minute. This pulp slurry was mixed using a TAPPI standard hand-made papermaking machine (using an 80-mesh screen) to obtain a pulp basis weight of 300 g / m. 2 The wet paper thus made was couched (dehydrated) and then heat-pressed at 200°C and 0.05 MPa for 90 seconds using a heat press machine to obtain the grease-resistant paper of the present invention.

[0118] Examples 2 to 9 Grease-resistant paper was produced using the same procedure as in Example 1 under the conditions shown in the table.

[0119] [Comparative Examples 1, 3, and 4] Papermaking was carried out in the same manner as in Example 1, except that Starch A was not used, and test papers were prepared under the conditions shown in the table.

[0120] Comparative Example 2 Commercially available bagasse was mixed with water to a pulp concentration of 2.25% by mass, and a pulp slurry was produced using a laboratory disintegrator (3000 rpm, 5 minutes). The freeness was 420 mL at this time. The pulp was diluted with water to a pulp concentration of 1.5% by mass, and a 5% aqueous solution of starch A was added to the pulp (solid content) at 40% by mass, followed by stirring for 1 minute. Starch A was added to water and dissolved (gelatinized) at approximately 90°C to produce a 5% aqueous solution. This pulp slurry was mixed using a TAPPI standard hand-making machine (using an 80-mesh screen) to obtain a pulp basis weight of 300 g / m. 2 The wet paper thus made was couched (dehydrated) and then heat-pressed at 200°C and 0.05 MPa for 90 seconds using a heat press machine to obtain the grease-resistant paper of the present invention.

[0121] Example 10 Water was added to commercially available bagasse to a pulp concentration of 2.25% by mass, and a pulp slurry was produced using a laboratory disintegrator (3000 rpm, 5 minutes). The mixture was dewatered using a 150-mesh sieve to a pulp concentration of 10% by mass, and then beaten using a laboratory beater (PFI mill) to a freeness of 360 mL. The mixture was then diluted with water to a pulp concentration of 1% by mass, and starch A was added in powder form to a concentration of 40% by mass relative to the pulp (solid content), followed by stirring for 1 minute. This pulp slurry was then sieved using a TAPPI standard hand-making machine (using an 80-mesh screen) to a pulp basis weight of 100 g / m. 2 The wet paper thus made was couched (dehydrated) and then heat-pressed at 200°C and 0.05 MPa for 90 seconds using a heat press machine to obtain the grease-resistant paper of the present invention.

[0122] Example 11 Commercially available bagasse was mixed with water to a pulp concentration of 2.25% by mass, and a pulp slurry was produced using a laboratory disintegrator (3000 rpm, 5 minutes). The mixture was dewatered using a 150-mesh sieve to a pulp concentration of 10% by mass, and then beaten using a laboratory beater (PFI mill) to a freeness of 360 mL. The mixture was then diluted with water to a pulp concentration of 1% by mass, and calcium carbonate (OMYAFIL, manufactured by Omya) was added as powder to a concentration of 10% by mass relative to the pulp (solid content) and stirred for 1 minute. Starch A was then added as powder to a concentration of 40% by mass relative to the pulp (solid content) and stirred for another 1 minute. This pulp slurry was then mixed using a TAPPI standard hand-making machine (using an 80-mesh screen) to a pulp basis weight of 100 g / m. 2 The wet paper thus made was couched (dehydrated) and then heat-pressed at 200°C and 0.05 MPa for 90 seconds using a heat press machine to obtain the grease-resistant paper of the present invention.

[0123] Example 12 Papermaking was carried out in the same manner as in Example 10, except that the freeness was changed to 260 mL, and test papers were prepared under the conditions shown in the table.

[0124] Example 13 Papermaking was carried out in the same manner as in Example 11, except that the freeness was changed to 260 mL, and test papers were prepared under the conditions shown in the table.

[0125] [Comparative Examples 5 and 6] Papermaking was carried out in the same manner as in Example 10, except that Starch A was not used, and test papers were prepared under the conditions shown in the table.

[0126] Example 14 Commercially available bagasse was mixed with water to a pulp concentration of 2.25% by mass, and a pulp slurry was produced using a laboratory disintegrator (3000 rpm, 5 minutes). The freeness was 420 mL. The mixture was diluted with water to a pulp concentration of 1% by mass, and a sizing agent (alkyl ketene dimer, aqueous dispersion, active ingredient 15%) was added to the pulp (solid content) at 0.045% by mass, and the mixture was stirred for 1 minute. Starch A was then added in powder form to a pulp (solid content) at 40% by mass, and the mixture was stirred for another 1 minute. The pulp slurry was then sieved using a TAPPI standard hand-making machine (using an 80-mesh screen) until the pulp had a basis weight of 300 g / m. 2 The wet paper thus made was couched (dehydrated) and then heat-pressed at 200°C and 0.05 MPa for 90 seconds using a heat press machine to obtain the grease-resistant paper of the present invention.

[0127] Examples 15 to 18 Greaseproof paper was produced under the conditions shown in the table using the same procedure as in Example 14. In Examples 16 to 18, the order of addition of the sizing agent and starch A was reversed.

[0128] Comparative Example 7 Papermaking was carried out in the same manner as in Example 14, except that Starch A was not used, and test papers were prepared under the conditions shown in the table.

[0129] Example 19 Papermaking was carried out in the same manner as in Example 1, except that the pulp was changed from bagasse to a combination of LBKP and NBKP in a ratio of 7:3, and test papers were prepared under the conditions shown in the table.

[0130] Comparative Example 8 Papermaking was carried out in the same manner as in Example 19, except that Starch A was not used, and test papers were prepared under the conditions shown in the table.

[0131] Example 20 Commercially available bagasse was mixed with water to a pulp concentration of 2.25% by mass, and a pulp slurry was produced using a laboratory disintegrator (3000 rpm, 5 minutes). The freeness was 420 mL. The mixture was diluted with water to a pulp concentration of 1% by mass, and calcium carbonate (OMYAFIL, manufactured by Omya) was added in powder form to a concentration of 10% by mass relative to the pulp (solid content), followed by stirring for 1 minute. Next, starch A was added in powder form to a concentration of 40% by mass relative to the pulp (solid content), followed by stirring for another 1 minute. This pulp slurry was mixed using a TAPPI standard hand-making machine (using an 80-mesh screen) to obtain a pulp basis weight of 300 g / m. 2 The wet paper thus made was couched (dehydrated) and then heat-pressed at 200°C and 0.05 MPa for 90 seconds using a heat press machine to obtain the grease-resistant paper of the present invention.

[0132] [Examples 21, 22, and 24] Papermaking was carried out in the same manner as in Example 1, except that starch A was changed to starch B, C, or G, and test papers were prepared under the conditions shown in the table.

[0133] Example 23 Commercially available bagasse was mixed with water to a pulp concentration of 2.25% by mass, and a pulp slurry was produced using a laboratory disintegrator (3000 rpm, 5 minutes). At this time, the freeness was 420 mL. The pulp was diluted with water to a pulp concentration of 1% by mass, and starch A' was added in powder form to a concentration of 40% by mass relative to the pulp (solid content), followed by vigorous stirring using a laboratory disintegrator (3000 rpm) for 1 minute. This pulp slurry was mixed using a TAPPI standard hand-making machine (using an 80-mesh screen) to a pulp basis weight of 300 g / m. 2The wet paper thus made was couched (dehydrated) and then heat-pressed at 200°C and 0.05 MPa for 90 seconds using a heat press machine to obtain the grease-resistant paper of the present invention.

[0134] Comparative Examples 9 to 11 Papermaking was carried out in the same manner as in Example 20, except that starch A was changed to starches D to F, and test papers were prepared under the conditions shown in the table.

[0135] The evaluation results of Examples 1 to 23 and Comparative Examples 1 to 11 are shown in Tables 3 to 5.

[0136] [Table 3]

[0137] [Table 4]

[0138] [Table 5]

[0139] Comparative Example 12 Test papers were prepared by papermaking in the same manner as in Example 1, except that starch A was replaced with a 1:1 combination of starches D and E, but no oil resistance was obtained. Comparative Example 13 Using the same procedure as for Starch A', an aqueous solution of Starch D and Starch E in a 1:1 ratio was prepared and powdered. Test papers were prepared using the same procedure as in Example 23, except that Starch A' was replaced with the powder, but no oil resistance was obtained.

[0140] Example 25 Commercially available bagasse was mixed with water to a pulp concentration of 2.25% by mass, and a pulp slurry was produced using a laboratory disintegrator (3000 rpm, 5 minutes). The freeness was 420 mL. The pulp was diluted with water to a pulp concentration of 1% by mass, and starch A was added in powder form to a concentration of 20% by mass relative to the pulp (solid content), followed by stirring for 1 minute. Next, a sizing agent (wax-based emulsion, active content 29%) was added to a concentration of 5.0% by mass relative to the pulp (solid content), followed by stirring for 5 minutes. This pulp slurry was sieved using a TAPPI standard hand-made papermaking machine (using an 80-mesh screen) until the pulp had a basis weight of 300 g / m. 2 The wet paper was made so that the grease resistance was (theoretical value). The made wet paper was couched (dehydrated) and then heat-pressed at 170°C and 0.05 MPa for 90 seconds using a heat press machine to obtain the grease-resistant paper of the present invention. The results are shown in Table 6.

[0141] [Table 6]

[0142] Excellent oil resistance was obtained for all of Examples 1 to 25. Moreover, surprisingly, Example 1 etc. showed excellent oil resistance even at a temperature of 180°C. Furthermore, the starch of the present invention alone can provide a certain degree of water resistance, and by using it in combination with a sizing agent, it is possible to increase water resistance without reducing oil resistance.

[0143] The present invention makes it possible to produce greaseproof paper with excellent practicality. Furthermore, the main structure of the invention is plant-derived starch, and unlike conventional greaseproofing agents, it does not use fluorine compounds, significantly reducing the use of petroleum-derived raw materials, making it environmentally friendly.

Claims

1. An oil-proofing agent for paper that is added to the inside of paper by internal addition treatment, The paper oil-proofing agent contains quaternary cationized starch, The quaternary cationized starch is a reaction product of starch with a quaternary ammonium compound having a glycidyl group or a derivative thereof, An oil-proofing agent for paper that satisfies the following condition 1 and / or condition 2: Condition 1: The cationic charge amount of the quaternary cationized starch is 160 to 470 μeq / g. Condition 2: When the amount of the structure derived from starch in the quaternary cationized starch is taken as 100 parts by mass, the amount of the structure derived from the quaternary ammonium compound or a derivative thereof is 1.2 to 9.0 parts by mass.

2. the quaternary ammonium compound having a glycidyl group is at least one selected from glycidyltrialkylammonium salts, glycidyldialkylbenzylammonium salts, glycidylalkyldibenzylammonium salts, glycidyltribenzylammonium salts, glycidyldialkylphenylammonium salts, glycidylalkyldiphenylammonium salts, glycidyltriphenylammonium salts, glycidyldialkylcycloalkylammonium salts, glycidylalkyldicycloalkylammonium salts, and glycidyltricycloalkylammonium salts, each of which has a counter ion other than a fluoride ion; The derivative of the quaternary ammonium compound having a glycidyl group may be selected from the group consisting of 3-chloro-2-hydroxypropyltrialkylammonium salts, 3-chloro-2-hydroxypropyldialkylbenzylammonium salts, 3-chloro-2-hydroxypropylalkyldibenzylammonium salts, 3-chloro-2-hydroxypropyltribenzylammonium salts, 3-chloro-2-hydroxypropyldialkylphenylammonium salts, 3-chloro-2-hydroxypropylalkyldiphenylammonium salts, 3-chloro-2-hydroxypropyltriphenylammonium salts, 3-chloro-2-hydroxypropyldialkylcycloalkylammonium salts, 3-chloro-2-hydroxypropylalkyldicycloalkylammonium salts, 3-chloro-2-hydroxypropyltricycloalkylammonium salts, 3-bromo-2-hydroxypropyltrialkylammonium salts, 3-bromo-2-hydroxypropyldialkylbenzylammonium salts, 3-bromo-2-hydroxypropylalkyldibenzylammonium salts, and 3-bromo-2-hydroxypropyltriphenylammonium salts, in which the counter ion is not a fluoride ion. hydroxypropyltribenzylammonium salt, 3-bromo-2-hydroxypropyldialkylphenylammonium salt, 3-bromo-2-hydroxypropylalkyldiphenylammonium salt, 3-bromo-2-hydroxypropyltriphenylammonium salt, 3-bromo-2-hydroxypropyldialkylcycloalkylammonium salt, 3-bromo-2-hydroxypropylalkyldicycloalkylammonium salt, 3-bromo-2-hydroxypropyltricycloalkylammonium salt, 3-iodo-2-hydroxypropyltrialkylammonium salt, 3-iodo-2-hydroxypropyldialkylbenzylammonium salt, 3-iodo-2-hydroxypropylalkyldibenzylammonium salt, 3-iodo-2-hydroxypropyltribenzylammonium salt, 3-iodo-2-hydroxypropyldialkylphenylammonium salt, 3-iodo-2-hydroxypropylalkyldiphenylammonium salt, 3-iodo-2-hydroxypropyltriphenylammonium salt, 3-iodo-2-hydroxypropyldialkylcycloalkylammonium salt,The oil-proofing agent for paper according to claim 1, which is at least one selected from 3-iodo-2-hydroxypropylalkyldicycloalkylammonium salts and 3-iodo-2-hydroxypropyltricycloalkylammonium salts.

3. The glycidyl group-containing quaternary ammonium compound and its derivative are selected from the group consisting of glycidyl trimethylammonium chloride, glycidyl trimethylammonium bromide, glycidyl trimethylammonium iodide, 3-chloro-2-hydroxypropyl trimethylammonium chloride, 3-chloro-2-hydroxypropyl trimethylammonium bromide, 3-chloro-2-hydroxypropyl trimethylammonium iodide, 3-bromo-2-hydroxypropyl trimethylammonium chloride, 3-bromo-2-hydroxypropyl trimethylammonium bromide, 3-bromo-2-hydroxypropyl trimethylammonium iodide, 3-iodo-2-hydroxypropyl trimethylammonium chloride, 3-iodo-2-hydroxypropyl trimethylammonium bromide, and 3-iodo-2-hydroxypropyl trimethylammonium iodide. The greaseproofing agent for paper according to claim 2, wherein the quaternary ammonium compound and its derivative are selected from the group consisting of glycidyl trimethylammonium chloride, glycidyl trimethylammonium bromide, glycidyl trimethylammonium iodide, 3-chloro-2-hydroxypropyl trimethylammonium chloride, 3-bromo-2-hydroxypropyl trimethylammonium bromide, and 3-iodo-2-hydroxypropyl trimethylammonium iodide.

4. The oil-proofing agent for paper according to any one of claims 1 to 3, further comprising inorganic particles and / or a sizing agent.

5. The oil-proofing agent for paper according to any one of claims 1 to 3, which is added to the inside of paper used for food contact applications.

6. Grease-resistant paper containing the grease-proofing agent for paper according to claim 1 therein.

7. The oil-resistant paper according to claim 6, wherein the content of the quaternary cationized starch is 3 to 80% by mass relative to the mass of the pulp.

8. 8. The greaseproof paper according to claim 6 or 7, further comprising inorganic particles and / or a sizing agent.

9. 8. Greaseproof paper according to claim 6 or 7, for use in food contact applications.

10. Basis weight: 50 g / m 2 The greaseproof paper according to claim 6 or 7.

11. The greaseproof paper according to claim 6 or 7, which is a food packaging material or a food container.

12. The oil-resistant paper according to claim 6 or 7, which is evaluated as ○ or △ by the following oil resistance test method. [Oil resistance test method] The greaseproof paper was cut into a 4 cm x 5 cm rectangle. 75 mg of soybean oil at room temperature (25°C) was dropped onto the surface of the greaseproof paper, and the paper was left to stand at room temperature (25°C) for 30 minutes. The state of penetration of the soybean oil was visually observed and evaluated based on the following criteria. ○: No penetration is observed on the dropped surface of the greaseproof paper, or no penetration is observed when the greaseproof paper is observed from the back side (no color change). △: When the greaseproof paper is observed from the back side, slight penetration is observed (slight color change). ×: When the greaseproof paper is observed from the back side, the ink has completely penetrated.

13. A method for producing greaseproof paper according to claim 6, A method for producing greaseproof paper, comprising the step of adding the quaternary cationized starch in the form of particles having an average particle size of 0.1 to 500 μm to a pulp slurry used in papermaking.

14. The method for producing greaseproof paper according to claim 13, further comprising the step of adding inorganic particles and / or a sizing agent to the pulp slurry used in papermaking.