Non-fluorine oil-resistant agent for base paper, and oil-resistant paper

Abstract

To provide a non-fluorine-based oil-resistant agent for base paper capable of obtaining oil-resistant paper having excellent oil resistance and air permeability.SOLUTION: A non-fluorine-based oil-resistant agent for base paper, comprising a polyglycerol fatty acid ester and a solvent, wherein the polyglycerol fatty acid ester is (a) a polyglycerol fatty acid ester which is an esterified product of two or more linear saturated fatty acids having 14 or more carbon atoms and a polyglycerol having an average degree of polymerization of 4 or more, and / or (b) a polyglycerol fatty acid ester which is an esterified product of at least one linear saturated fatty acid having 18 or more carbon atoms and a polyglycerol having an average degree of polymerization of 4 or more.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a non-fluorine-based oil-proofing agent for base paper and to oil-resistant paper. [Background technology]

[0002] Fluorinated organic compounds (PFAS) are known to have excellent oil and water repellency due to their low surface free energy (surface tension). Fluorine has the highest electronegativity of any atom, resulting in a large C—F bond energy, which gives it excellent chemical stability, including excellent heat and chemical resistance. They are therefore used in a variety of applications, including greaseproof paper and raincoats.

[0003] Greaseproof paper is usually obtained by treating a base material such as paper with an oil-proofing agent. Treatment methods include coating or impregnating the base material such as paper with the oil-proofing agent, or making a paper from a pulp slurry containing the oil-proofing agent. Such greaseproof paper is broadly classified into fluorine-based greaseproof paper and non-fluorine-based greaseproof paper. Non-fluorine-based greaseproof paper generally exhibits oil resistance by forming a layer of the non-fluorine-based greaseproofing agent on the paper surface without any gaps, and therefore has poor breathability. On the other hand, fluorine-based greaseproofing agents are able to exhibit oil resistance and also have breathability due to the chemical properties described above, even when there are gaps through which steam can pass.

[0004] Known fluorine-based oil-resistant agents include, for example, those containing a specific fluorine-containing polymer, a polyglycerol fatty acid ester, and an aqueous medium (Patent Document 1). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] International Publication No. 2021 / 235452 Summary of the Invention [Problem to be solved by the invention]

[0006] Fluorinated organic compounds (PFAS) have excellent oil resistance and breathability, but among them, perfluorooctanoic acid (PFOA), perfluorooctane sulfonic acid (PFOS), and perfluorohexane sulfonic acid (PFHxS) have excellent stability, but there are concerns about health risks such as bioaccumulation, and restrictions on their use are being tightened. Since the fewer carbon atoms a compound has, the less likely it is to bioaccumulate, PFAS with fewer carbon atoms are also being commercialized, but as the industry as a whole is shying away from fluorine, there is a demand for the development of non-fluorinated, breathable oil-resistant agents.

[0007] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a non-fluorine-based oil-proofing agent for base paper which can produce oil-resistant paper having excellent oil resistance and breathability. [Means for solving the problem]

[0008] That is, the present invention relates to [1] a non-fluorine-based oil-proofing agent for base paper, which contains a polyglycerol fatty acid ester and a solvent and is used for base paper, wherein the polyglycerol fatty acid ester is (a) a polyglycerol fatty acid ester that is an esterification product of two or more linear saturated fatty acids having 14 or more carbon atoms and a polyglycerol having an average degree of polymerization of 4 or more, and / or (b) a polyglycerol fatty acid ester that is an esterification product of at least one linear saturated fatty acid having 18 or more carbon atoms and a polyglycerol having an average degree of polymerization of 4 or more.

[0009] The present invention also relates to [2] the non-fluorinated oil-proofing agent for base paper according to [1] above, wherein the content of the polyglycerol fatty acid ester in the solid content of the oil-proofing agent is preferably 50 mass % or more.

[0010] The present invention also relates to [3] the non-fluorinated oil-proofing agent for base paper according to either [1] or [2] above, wherein the linear saturated fatty acid in component (a) and / or component (b) is preferably stearic acid.

[0011] The present invention also relates to [4] the non-fluorinated oil-proofing agent for base paper according to any one of the above [1] to [3], wherein the solvent is preferably water.

[0012] The present invention also relates to [5] the non-fluorinated oil-proofing agent for base paper according to any one of the above [1] to [4], wherein the component (b) is preferably polyglyceryl-5 stearate and / or polyglyceryl-10 stearate.

[0013] The present invention also relates to [6] the non-fluorine-based oil-proofing agent for base paper according to the above [4], which preferably further contains urea.

[0014] Furthermore, the present invention relates to [7] greaseproof paper obtained by impregnating a base paper with any one of the non-fluorine-based oil-proofing agents for base paper according to [1] to [6] above and drying the impregnated base paper. [Effects of the Invention]

[0015] The non-fluorine-based oil-proofing agent for base paper of the present invention is a non-fluorine-based composition containing (a) a polyglycerol fatty acid ester, which is an esterification product of two or more linear saturated fatty acids having 14 or more carbon atoms and a polyglycerol having an average degree of polymerization of 4 or more, and / or (b) a polyglycerol fatty acid ester, which is an esterification product of at least one linear saturated fatty acid having 18 or more carbon atoms and a polyglycerol having an average degree of polymerization of 4 or more, and a solvent, and therefore enables the production of oil-resistant paper with excellent oil resistance and breathability. DETAILED DESCRIPTION OF THE INVENTION

[0016] <Non-fluorine oil-resistant agent for base paper> The non-fluorine-based oil-proofing agent for base paper of the present invention contains a polyglycerol fatty acid ester and a solvent, and is used for base paper. Here, "non-fluorine-based" means that the oil-proofing agent is substantially free of compounds having fluorine atoms, and the content of the fluorine-containing compounds in the oil-proofing agent is preferably 0.1 mass% or less, more preferably 0.05 mass% or less, even more preferably 0.01 mass% or less, and most preferably 0 mass% (no compounds having fluorine atoms are included).

[0017] <Polyglycerin fatty acid ester> The polyglycerol fatty acid ester is (a) a polyglycerol fatty acid ester which is an esterification product of two or more linear saturated fatty acids having 14 or more carbon atoms and a polyglycerol having an average degree of polymerization of 4 or more, and / or (b) a polyglycerol fatty acid ester which is an esterification product of at least one linear saturated fatty acid having 18 or more carbon atoms and a polyglycerol having an average degree of polymerization of 4 or more.

[0018] The (a) polyglycerol fatty acid ester, which is an esterification product of two or more linear saturated fatty acids having 14 or more carbon atoms and a polyglycerol having an average degree of polymerization of 4 or more, is an esterification product of a linear saturated fatty acid having 14 or more carbon atoms and a polyglycerol having an average degree of polymerization of 4 or more, and has two or more linear saturated carbon groups having 14 or more carbon atoms and a polyglycerol skeleton having an average degree of polymerization of 4 or more. The (a) component may be used alone or in combination of two or more types.

[0019] In the component (a), the linear saturated fatty acid having 14 or more carbon atoms preferably has 14 or more carbon atoms, more preferably 18 or more carbon atoms, in organic solvent systems. Furthermore, in aqueous systems, from the viewpoint of water solubility, the linear saturated fatty acid preferably has 20 or less carbon atoms, more preferably 18 or less carbon atoms. Examples of linear saturated fatty acids having 14 or more carbon atoms include myristic acid, palmitic acid, stearic acid, arachidic acid, and behenic acid. Among these, stearic acid, arachidic acid, and behenic acid are preferred for organic solvent systems, and myristic acid and stearic acid are preferred for aqueous systems from the viewpoint of water solubility. Furthermore, for aqueous systems, fatty acids with an HLB of 10 or more are preferred.

[0020] In the component (a), the polyglycerol having an average degree of polymerization of 4 or more preferably has an average degree of polymerization of 6 or more, and more preferably 10 or more. The average degree of polymerization is determined using the hydroxyl value (mgKOH / g) according to JIS K 1557-1:2009. Specifically, when 56.1×1000 / hydroxyl value=A, the average degree of polymerization can be calculated using the formula {(2×A−18.0) / (74.1−A)}.

[0021] Examples of component (a) include polyglyceryl-10 dimyristate, polyglyceryl-10 trimyristate, polyglyceryl-10 dipalmitate, polyglyceryl-10 tripalmitate, polyglyceryl-10 distearate, and polyglyceryl-10 tristearate. Of these, for organic solvent-based systems, polyglyceryl-10 distearate, polyglyceryl-10 tristearate, polyglyceryl-10 pentastearate, and polyglyceryl-10 decaglycerin stearate are preferred, and for aqueous systems, polyglyceryl-10 dimyristate and polyglyceryl-10 distearate are preferred.

[0022] The (b) polyglycerol fatty acid ester, which is an esterification product of at least one linear saturated fatty acid having 18 or more carbon atoms and a polyglycerol having an average degree of polymerization of 4 or more, is an esterification product of a linear saturated fatty acid having 18 or more carbon atoms and a polyglycerol having an average degree of polymerization of 4 or more, and has at least one linear saturated carbon group having 18 or more carbon atoms and a polyglycerol skeleton having an average degree of polymerization of 4 or more. The (b) component may be used alone or in combination of two or more types.

[0023] In the component (b), the linear saturated fatty acid having 18 or more carbon atoms may have 18 or more carbon atoms in a solvent-based system, but in an aqueous system, from the viewpoint of water solubility, the number of carbon atoms is preferably 20 or less, and more preferably 18 or less. Examples of linear saturated fatty acids having 18 or more carbon atoms include stearic acid, arachidic acid, and behenic acid. Of these, stearic acid is preferred in an aqueous system from the viewpoint of water solubility.

[0024] In the component (b), the polyglycerol having an average degree of polymerization of 4 or more preferably has an average degree of polymerization of 6 or more, and more preferably 10 or more. The average degree of polymerization can be calculated by the method described above.

[0025] Examples of component (b) include polyglyceryl-4 stearate, polyglyceryl-5 stearate, polyglyceryl-6 stearate, polyglyceryl-10 stearate, and polyglyceryl-10 behenate. Among these, polyglyceryl-4 stearate, polyglyceryl-5 stearate, polyglyceryl-6 stearate, and polyglyceryl-10 stearate are preferred for organic solvent-based systems, and polyglyceryl-5 stearate and polyglyceryl-10 stearate are preferred for aqueous systems.

[0026] Examples of the solvent include water and organic solvents such as toluene, methyl ethyl ketone, xylene, ethanol, isopropyl alcohol, etc. From the viewpoint of reducing VOCs, which is a recent social issue, the solvent is preferably water or water containing a water-soluble organic solvent, and more preferably water.

[0027] In order to ensure oil resistance, the content of the polyglycerol fatty acid ester in the solid content of the oil-proofing agent is preferably 50% by mass or more, more preferably 60% by mass or more, and even more preferably 75% by mass or more. Note that the "solid content" refers to non-volatile components excluding the solvent and the like.

[0028] When the non-fluorinated oil-proofing agent for base paper is aqueous, it may contain urea, glycerin, etc. from the viewpoint of stability, that is, to prevent the polyglycerol fatty acid ester from liquid crystallizing at temperatures between room temperature and around 40° C. Generally, the amount of urea, etc., is preferably 50 mass % or less, more preferably 3 to 40 mass %, and even more preferably 5 to 30 mass %, of the solid content of the oil-proofing agent.

[0029] <Other additives> The non-fluorine-based oil-proofing agent for base paper may contain additives such as water repellents, antifoaming agents, paper strengthening agents, sizing agents, pigments, deodorizing agents, penetrating agents, and coloring agents, as required.

[0030] <Method of manufacturing non-fluorine-based oil-proofing agent for base paper> The method for producing the non-fluorine-based oil-proofing agent for base paper is not particularly limited, and for example, the polyglycerol fatty acid ester, the solvent, etc. are mixed, heated as necessary, and thoroughly stirred and mixed to prepare a non-fluorine-based oil-proofing agent for base paper of a predetermined concentration.

[0031] <Oil-resistant paper> The greaseproof paper of the present invention is obtained by impregnating a base paper with the non-fluorinated oil-proofing agent for base paper and drying it. The base paper is not particularly limited as long as it is a commonly used paper containing plant-derived pulp as a main component, and examples thereof include paper substrates such as paper, cardboard, pulp mold, interleaf paper using synthetic fibers as part of the raw material, and related products.

[0032] The impregnation (application) of the oil-resistant agent may be carried out at any stage after papermaking, such as at the size press stage after papermaking, wet pressing, and pre-drying, or at a stage using a coater after the size press. A coater may be used for application. Examples of the coater include a size press. Examples of the size press include a two-roll size press, a film transfer size press, and a calendar size press.

[0033] After impregnating (applying) the oil-proofing agent, the base paper is dried. The drying method may be a method of drying with heat or a method of drying without heat (air drying). The drying temperature is preferably 20 to 300°C, more preferably 20 to 250°C. [Example]

[0034] The non-fluorine-based oil-proofing agent for base paper and oil-resistant paper of the present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0035] Example 1 <Method of manufacturing non-fluorine-based oil-proofing agent for base paper> A non-fluorine-based oil-proofing agent for base paper was produced by heating and stirring 15 g of polyglycerol dimyristate-10 (HLB: 12.3) as a polyglycerol fatty acid ester and 85 g of water at 60-70°C for 30 minutes.

[0036] <Production of oil-resistant paper> Basis weight 30g / m 2 For thin paper, the oil-resistant agent is added at 3.4g / m2 in dry mass equivalent. 2 The paper was coated by the size press method so that the thickness was as follows: and dried at 120°C for 30 seconds to produce oil-resistant paper.

[0037] <Examples 2-8, Comparative Examples 1-13> Instead of the raw materials used in Example 1, the raw materials shown in Tables 1, 3, and 4 were used to produce non-fluorinated oil-proofing agents for base paper in the same manner as in Example 1, and then oil-resistant paper was produced.

[0038] <Examples 9-13> 15 g of polyglycerol fatty acid ester, polyglyceryl-10 stearate (HLB: 13.4), and 85 g of water were heated and stirred at 60-70°C for 30 minutes, and then 1 g of urea was added in Example 9, 2 g in Example 10, 5 g in Example 11, 7 g in Example 12, and 10 g in Example 13, and the mixture was stirred for a further 10 minutes to produce a non-fluorine-based oil-proofing agent for base paper, and then oil-resistant paper was produced.

[0039] The greaseproof paper obtained above was subjected to the following evaluations, and the results are shown in Table 1-3.

[0040] <Evaluation of oil resistance> The oil resistance was evaluated using the oil-resistant paper obtained above in accordance with the TAPPI UM-557 "Repellency of Paper and Board to Grease, Oil, and Waxes (Kit Test)" standard. The following "◎", "〇", or "△" were used as the pass criteria, with "◎" or "〇" being preferred, and "◎" being more preferred. [standard] ◎: Kit value is 4 or more. O: Kit value is greater than 3 and less than 4. △: Kit value is 3. ×: Kit value is less than 3.

[0041] <Breathability evaluation> The breathability of the oil-resistant paper obtained above was evaluated using an Oken air permeability tester in accordance with JAPAN TAPPI Paper and Pulp Testing Method No. 5-2: 2000. The pass criteria were "◎", "〇", or "△", with "◎" or "〇" being preferred and "◎" being more preferred. [standard] ◎: Less than 1200 seconds. ○: Between 1200 seconds and 3000 seconds. △: 3000 seconds or more but less than 5000 seconds. ×: 5000 seconds or more.

[0042] [Table 1]

[0043] [Table 2]

[0044] [Table 3]

[0045] [Table 4]

[0046] The raw materials listed in Tables 1-4 are as follows: Polyglyceryl-10 dimyristate (HLB: 12.3) Polyglyceryl-5 stearate (HLB: 15.0) Polyglyceryl-10 stearate (HLB: 13.4) Polyglyceryl-4 stearate (HLB: 8.4) Polyglyceryl-10 distearate (HLB: 11.0) Polyglyceryl-10 pentastearate (HLB: 7.0) Polyglyceryl-6 caprylate (HLB: 14.6) Polyglyceryl-10 caprylate (HLB: 16.1) Polyglyceryl-10 laurate (HLB: 14.7) Polyglyceryl-10 trilaurate (HLB: 10.4) Polyglyceryl-5 myristate (HLB: 15.4) Polyglyceryl-10 myristate (HLB: 15.7) Polyglyceryl-10 diisostearate (HLB: 11.1) Polyglyceryl-6 oleate (HLB: 11.6) Polyglyceryl-10 oleate (HLB: 12.9) Polyglyceryl-10 dioleate (HLB: 11.9)

Claims

1. An oil-proofing agent for use on base paper, comprising a polyglycerol fatty acid ester and a solvent, The polyglycerol fatty acid ester is (a) a polyglycerol fatty acid ester which is an esterification product of two or more linear saturated fatty acids having 14 or more carbon atoms and a polyglycerol having an average degree of polymerization of 4 or more, and / or (b) a polyglycerol fatty acid ester which is an esterification product of at least one linear saturated fatty acid having 18 or more carbon atoms and a polyglycerol having an average degree of polymerization of 4 or more.

2. 2. The non-fluorinated oil-proofing agent for base paper according to claim 1, wherein the content of the polyglycerol fatty acid ester in the solid content of the oil-proofing agent is 50 mass % or more.

3. 3. The non-fluorine-based oil-proofing agent for base paper according to claim 1, wherein the linear saturated fatty acid in the component (a) and / or the component (b) is stearic acid.

4. 3. The non-fluorinated oil-proofing agent for base paper according to claim 1, wherein the solvent is water.

5. 3. The non-fluorine-based oil-proofing agent for base paper according to claim 1, wherein the component (b) is polyglyceryl-5 stearate and / or polyglyceryl-10 stearate.

6. The non-fluorine-based oil-proofing agent for base paper according to claim 4, further comprising urea.

7. 3. Grease-resistant paper obtained by impregnating a base paper with the non-fluorine-based oil-proofing agent for base paper according to claim 1 or 2 and drying the impregnated base paper.

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