Waterproof paper joined body

Abstract

To provide a water-resistant paper joined body having excellent water resistance and capable of excellently joining first water-resistant paper and a joining object.SOLUTION: The waterproof paper joined body 1 has a first waterproof paper 2, a joining member 3, and a joining object 4. The first waterproof paper 2 and the joining object 4 are joined via a joining member 3. The first waterproof paper 2 is formed by applying a composition containing 2 mass% or more of fats and oils and polyphenols to a base material. The bonding member 3 is an adhesive. The adhesive contains a base polymer having a glass transition point of -50 °C. to -10 °C. The adhesive force of the adhesive to the SUS plate is 7N / 10mm or more. The object to be joined 4 may be a second waterproof paper.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a waterproof paper joined body formed by joining waterproof paper and an object to be joined via a joining member. [Background technology]

[0002] In recent years, the issue of microplastics has been raised in environmental protection, particularly in the marine environment. In response to this issue, paper products have increasingly been used as an alternative to plastic products. For example, paper products include familiar consumables such as paper bags, paper plates, paper cups, and straws. However, paper products are vulnerable to water. Therefore, paper products are required to be water-repellent or water-resistant. Various countermeasures have been implemented, such as laminating the paper surface or adding synthetic resins as binders to paper products. However, all of these countermeasures use synthetic resins to achieve water-repellency or water-resistance, and therefore have not provided a sufficient solution to the microplastic problem.

[0003] PCT / JP2023 / 044632 (Patent Document 1) discloses a water-resistant substrate. The water-resistant substrate is formed by applying a composition containing polyphenols (persimmon tannins), oils and fats (vegetable oils and fats), and lecithin (egg yolk lecithin or soybean lecithin) to a substrate made of cellulose cloth and paper. This ensures excellent water resistance, and since the composition is made from food-based ingredients to ensure water resistance, it can also help solve the microplastic problem. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] PCT / JP2023 / 044632 issue Summary of the Invention

[0005] However, the water-resistant substrate (water-resistant paper) of Patent Document 1 has a water-repellent surface, making it difficult to adhere to an object to be joined using a water-based adhesive. An example of a water-based adhesive is a starch glue, which is generally used to adhere paper to paper. Therefore, it is necessary to adhere the water-resistant paper to an object to be joined without applying a water-repellent treatment, for example, by not applying the above-mentioned composition to the marginal area of ​​the waterproof paper, which increases the processing cost of the waterproof paper.

[0006] The present disclosure has been made in consideration of the above circumstances, and aims to provide a waterproof paper joint body formed by joining waterproof paper that has been made drainable using polyphenols and oils and fats to an object to be joined using a specified joining member.

[0007] In order to solve the above problems, the present disclosure is configured as follows. That is, the waterproof paper bonded body according to the present disclosure includes a first waterproof paper coated with a composition containing oils and polyphenols, an object to be bonded to the first waterproof paper, and a bonding member that bonds the first waterproof paper to the object to be bonded. The content of the oil in the composition is 2 mass% or more. The bonding member includes an adhesive. The adhesive includes a base polymer having a glass transition point of -50°C to -10°C. The adhesive strength of the adhesive to SUS plate measured in accordance with JIS Z 0237 (2022) is 7 N / 10 mm or more.

[0008] According to the present disclosure, it is possible to obtain a waterproof paper joined body that has excellent water resistance and can satisfactorily join the waterproof paper and the object to be joined. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a perspective view showing the exterior of a waterproof paper bonded body. [Figure 2] FIG. 2 is an external perspective view showing the adhesive tape of the joining member. DETAILED DESCRIPTION OF THE INVENTION

[0010] (Configuration 1) A waterproof paper bonded product according to an embodiment of the present disclosure includes a first waterproof paper coated with a composition containing oils and polyphenols, an object to be bonded to the first waterproof paper, and a bonding member that bonds the first waterproof paper to the object. The oil content in the composition is 2% by mass or more. The bonding member includes an adhesive. The adhesive includes a base polymer having a glass transition temperature of -50°C to -10°C. The adhesive strength of the adhesive to SUS plate measured in accordance with JIS Z 0237 (2022) is 7 N / 10 mm or more.

[0011] This makes it possible to obtain a waterproof paper joined body that has excellent water resistance and can satisfactorily join the first waterproof paper and the object to be joined.

[0012] (Configuration 2) In the waterproof paper bonded body of Configuration 1, the object to be bonded may be a second waterproof paper coated with the composition of Configuration 1. Even when the object to be bonded is the second waterproof paper, the waterproof papers of the first waterproof paper and the second waterproof paper can be bonded well to each other.

[0013] (Configuration 3) In the waterproof paper joined body of the first or second aspect, the adhesive strength to the SUS plate of the adhesive may be 11.5 N / 10 mm or more, thereby enabling a better joining between the first waterproof paper and the joining object.

[0014] (Configuration 4) In the waterproof paper bonded body of any one of Configurations 1 to 3, the base polymer may contain at least one of styrene-isobutylene-styrene rubber and acrylic resin, thereby enabling a better bonding between the first waterproof paper and the bonding object.

[0015] (Configuration 5) In the waterproof paper bonded body of any one of Configurations 1 to 4, the adhesive may contain an additive. The base polymer may be contained in the adhesive so that the base polymer accounts for 96 mass % or more of the total of the base polymer and the additive. This allows for good bonding between the first waterproof paper and the object to be bonded, even when the adhesive contains an additive.

[0016] (Configuration 6) In the waterproof paper bonded body of any one of configurations 1 to 5, the composition may further contain lecithin and satisfy the following formulas (1) and (2). 5 <F / L<150 (1) 1.0 <F / P<25 (2) In the above formulas (1) and (2), F represents the content (% by mass) of the fat or oil relative to the composition, L represents the content (% by mass) of the lecithin relative to the composition, and P represents the content (% by mass) of polyphenols relative to the composition. The composition is emulsified by mixing the ingredients. By satisfying the above formula (1), the stability of the emulsion of the composition can be ensured. Furthermore, by satisfying formula (2), the water resistance of the waterproof paper can be improved and the composition can be properly applied to the waterproof paper.

[0017] (Configuration 7) In the waterproof paper bonded body of any one of Configurations 1 to 6, the composition may further contain casein and satisfy the following formulas (3) and (4). 10 <F / C<150 (3) 1.0 <F / P<70 (4) In the above formulas (3) and (4), F represents the content (% by mass) of the fat or oil relative to the composition, C represents the content (% by mass) of the casein relative to the composition, and P represents the content (% by mass) of the polyphenols relative to the composition. The composition is emulsified by mixing the ingredients. By satisfying the above formulas (3) and (4), the stability of the emulsion of the composition can be ensured. Furthermore, excellent water resistance can be imparted to waterproof paper.

[0018] (Configuration 8) In the waterproof paper bonded body of any one of Configurations 1 to 7, the oil or fat may have an iodine value of 130 to 250. This can facilitate solidification of the composition.

[0019] (Configuration 9) In the waterproof paper bonded body of any one of Configurations 1 to 8, the polyphenols may be at least one of tannins and flavonoids, which can further improve the water resistance of the first waterproof paper and, ultimately, the waterproof paper bonded body.

[0020] (Configuration 10) In the waterproof paper bonded body of any one of Configurations 1 to 9, the bonding member may be an adhesive tape. The adhesive tape may include a tape substrate and an adhesive applied to at least one main surface of the tape substrate.

[0021] An embodiment of the waterproof paper bonded assembly 1 of the present disclosure will be specifically described below with reference to Figures 1 and 2. Note that identical or corresponding components in the figures are denoted by the same reference numerals, and the same description will not be repeated. Note that, for ease of understanding, the drawings referred to below show simplified or schematic configurations, and some components are omitted.

[0022] As shown in FIG. 1, the waterproof paper bonded body 1 includes a waterproof paper 2 (first waterproof paper), a bonding member 3, and an object 4 to be bonded.

[0023] The waterproof paper 2 can be formed by applying a composition described below to a substrate made of cellulose cloth paper. The substrate may be not only cellulose cloth paper but also a paper sheet such as cardboard, and may also include a molded body injection-molded from pulp. In other words, in this disclosure, the substrate is not limited to a sheet but also includes a three-dimensional object, and further includes not only intermediate parts used as materials for manufacturing a finished product but also finished products.

[0024] Cellulose cloth paper is a cloth paper whose main component is cellulose fiber. Cloth paper is a general term for paper and cloth. Examples of cloth include nonwoven fabric, woven fabric, and felt. There are no particular limitations on the cellulose cloth paper, and it can be selected appropriately depending on the application of the waterproof paper 2. However, the cellulose cloth paper is preferably paper. Examples of paper include filter paper, kraft paper, and processed base paper. The basis weight of cellulose cloth paper is 30 g / m 2It is better to have more than 50g / m 2 More preferably, it is 500 g / m or more. 2 It is better to have less than 300g / m 2 Preferably, it is:

[0025] The method for applying the composition to the substrate may be any known method, and is not particularly limited. Examples include a method of applying the composition using a brush or the like, a method of immersing the substrate in the composition and applying it, and a method of spraying the composition onto the substrate using a spray or the like. The composition may be diluted with water or the like to facilitate application to the substrate. Depending on the material of the substrate, the composition may form a coating on the surface of the substrate. Alternatively, for example, when cellulose cloth paper is used as the substrate, the composition may be applied so that the entire cellulose cloth paper is impregnated with the composition, or only a portion of the cellulose cloth paper, for example, near the surface, may be impregnated with the composition.

[0026] The composition can include polyphenols and oils and fats. The composition is applied to a substrate for the purpose of making it water-resistant. Therefore, the composition can be used as a "paint," and the paint can include the composition.

[0027] The polyphenols may be naturally occurring or synthetically produced as antioxidants. The polyphenols contained in the composition of the present disclosure are preferably flavonoids or tannins.

[0028] Examples of flavonoids include catechins contained in green tea, flavonols such as quercetin contained in onions, isoflavones contained in soybeans, and anthocyanins contained in blueberries. The flavonoids may contain one or more selected from the group consisting of these various flavonoids. Among these, catechins are more preferred.

[0029] Examples of tannins include persimmon tannin (persimmon tannin), cinnamon, tannic acid, mimosa tannin, wattle tannin, quebracho (quebracho) tannin, chestnut tannin, myraborum tannin, myrobalan tannin, valonia tannin, sumac tannin, Gambia tannin, oak tannin, tara tannin, dividivi tannin, Borneo kacchi tannin, spruce tannin, and hemlock tannin, etc. The tannins may contain one or more types selected from the group consisting of these various tannins.

[0030] The fat or oil may be either vegetable fat or animal fat. However, from the viewpoint of economic cost or availability, vegetable fat or oil is preferred. Furthermore, from the viewpoint of ease of solidification, drying oil is more preferred. Drying oil (unsaturated fatty acid) is an oil with an iodine value of 130 or more, and solidifies by oxidation. From the viewpoint of ease of solidification, the iodine value of drying oil is preferably 130 or more, more preferably 150 or more. There is no particular upper limit for the iodine value, but, for example, 250 or less is preferred, more preferably 200 or less. The iodine value can be measured by a method in accordance with JIS K0070. In addition, canola oil (rapeseed oil), palm oil, or coconut oil may be used as fat or oil other than drying oil.

[0031] The content F of the oil / fat relative to the composition can be 2% by mass or more. This can improve water repellency. Furthermore, the content F of the oil / fat relative to the composition can be less than 50% by mass. This can prevent the oil / fat from transferring to other substrates, particularly the substrates placed below, when multiple substrates (waterproof papers) coated with the composition are stacked and stored or transported.

[0032] Drying oils among vegetable oils include, for example, soybean oil, perilla oil, linseed oil, tung oil, mustard oil, perilla oil, walnut oil, safflower oil, sunflower oil, fish oil (sardine oil), black cumin seed oil, apple oil, grape seed oil, cactus oil, wheat germ oil, pumpkin seed oil, passion fruit seed oil, guava seed oil, borage oil, sissymbrium oil, pine nut oil, camelina oil, cranberry seed oil, lime seed oil, bitter melon oil, hemp oil, and sea buckthorn oil. Examples of suitable drying oils include watercress oil, evening primrose oil, strawberry oil, blackcurrant oil, rosehip oil, raspberry seed oil, Inca inchi oil, kiwi seed oil, calendula seed oil, chia seed oil, pomegranate seed oil, kukui nut oil, black currant seed oil, and borage seed oil, as well as processed oils such as stand linseed oil, boiled poppy oil, sun-bleached poppy oil, boiled linseed oil, and sun-bleached linseed oil. The drying oil may contain one or more selected from the group consisting of these various drying oils. From the viewpoint of ease of handling, the drying oil is preferably at least one selected from the group consisting of soybean oil, perilla oil, linseed oil, tung oil, mustard oil, shiso oil, walnut oil, safflower oil, and sunflower oil. Perilla oil contains palmitic acid with 16 carbon atoms, oleic acid and linoleic acid with 18 carbon atoms, and arachidic acid with 20 carbon atoms.

[0033] Examples of animal fats and oils include terrestrial animal fats and oils such as beef tallow, lard, mutton fat, and milk fat. Marine animal fats and oils such as fish oil, whale oil, sardine oil, and liver oil can also be used as long as they are drying oils, as they polymerize to a high molecular weight during the heat treatment described below. The fats and oils contained in the composition can include either animal fats and oils or vegetable fats and oils. That is, the composition may include vegetable fats and oils, animal fats, or a mixture of vegetable and animal fats and oils.

[0034] The bonding member 3 may use or contain an adhesive. The adhesive may contain a base polymer having a glass transition point of -50°C to -10°C. The base polymer having a glass transition point of -50°C to -10°C is, for example, styrene-isobutylene-styrene rubber or acrylic resin. That is, the base polymer may contain at least one of styrene-isobutylene-styrene rubber or acrylic resin.

[0035] The adhesive has an adhesive strength to SUS plate of 7 N / 10 mm or more. The adhesive strength to SUS plate can be measured in accordance with JIS Z 0237 (2022). From the viewpoint of obtaining a good bond between the waterproof paper 2 and the object to be bonded 4, the adhesive strength of the adhesive to SUS plate is preferably 7 N / 10 mm or more, and more preferably 11.5 N / 10 mm. There is no particular upper limit to the adhesive strength of the adhesive to SUS plate, but it can be, for example, 20 N / 10 mm or less.

[0036] The adhesive may further contain additives. When the adhesive contains additives, the base polymer may be contained in the adhesive so that the total mass of the base polymer and additives is 96% or more. This allows for better bonding between the waterproof paper 2 and the object to be bonded 4. The additives added to the adhesive are added to exhibit better adhesive properties, and include, for example, low molecular weight materials such as tackifiers, crosslinking agents, inorganic fillers, oils, organic solvents, antioxidants, etc.

[0037] The joining member 3 may be an adhesive tape. As shown in Fig. 2, the adhesive tape may include a tape substrate 31 and an adhesive 32 applied to at least one main surface of one or the other of the tape substrate 31. The adhesive 32 is as described above.

[0038] The objects to be joined 4 are not particularly limited as long as the waterproof paper 2 can be joined via the joining member 3. The objects to be joined 4 may be made of, for example, paper, wood, synthetic resin, pulp, or metal. The objects to be joined 4 may also be waterproof paper (second waterproof paper) coated with the above-mentioned composition.

[0039] Thus, the waterproof paper bonded body 1 can achieve excellent water resistance through the waterproof paper 2 coated with the above-mentioned composition, and even when coated with the above-mentioned composition, the bonding member 3 containing the above-mentioned adhesive can satisfactorily bond the waterproof paper 2 to the object 4 to be bonded. The waterproof paper bonded body 1 can be suitably used for, for example, paper packaging containers, paper packaging bags, paper cups, paper plates, paper straws and other paper tableware, paper food wrapping paper, umbrellas, paper lanterns, andon lanterns, folding fans, folding fans, shoji screens, fusuma sliding doors, folding screens, folding screens, mailing envelopes, paper ornaments, etc.

[0040] [Composition Variation 1] The composition may further contain lecithin. The lecithin may be lecithin contained in egg yolk or soybean, etc. The egg yolk is that of a chicken egg. However, the egg yolk may be that of a quail, ostrich, or other bird, since these egg yolks also contain egg yolk lecithin, which will be described later. Note that whole eggs may also be used as a raw material when producing the composition.

[0041] The composition may further contain vinegar, which may contain acetic acid as a main component, and preferably has a pH of 2 to 6.

[0042] Mayonnaise is an example of an ingredient containing fats and oils, egg yolk, and vinegar. Mayonnaise is an emulsified food with a high fat content, produced by emulsifying fats and oils with lecithin, a natural emulsifier found in egg yolk. Using mayonnaise as a substitute for fats and oils, egg yolk, and vinegar allows for easier and more cost-effective production of the composition. From the perspective of recycling, it is also possible to utilize mayonnaise that is no longer suitable for use as a food product. The mayonnaise used in the production of the composition can be prepared by thoroughly mixing egg yolk, acetic acid, and fats and oils (animal fats or vegetable fats and oils), adding a liquid containing the polyphenols described above (e.g., persimmon tannin paint) to the mayonnaise (fat, egg yolk, and acetic acid), placing the mixture in a sealed container, and emulsifying the mixture by vigorously shaking the sealed container. However, the method for producing the composition is not limited to this. For example, a method is conceivable in which drying oil is added to soybean lecithin, followed by the addition of vinegar or alcohol, etc., and then dispersing and mixing the mixture. That is, the composition is an emulsified mixture containing polyphenols, oils and fats, and lecithin. It is also possible to use commercially available mayonnaise containing salt, the main component of which is sodium chloride.

[0043] Furthermore, the vegetable alcohol is preferably mint oil. Mint oil is an alcohol having 10 to 40 carbon atoms. Thus, even when using an alcohol having 10 to 40 carbon atoms, excellent water resistance can be obtained, particularly when soybean lecithin is used as the lecithin. From the viewpoint of obtaining excellent water resistance, the alcohol preferably has 2 to 40 carbon atoms, and from the viewpoint of improving impregnation into the substrate (cellulose cloth / paper), it is preferable that the alcohol have 10 or less carbon atoms.

[0044] The composition may satisfy the following formulas (1) and (2): 5 <F / L<150 (1) 1.0 <F / P<25 (2) In formulas (1) and (2), P represents the content (% by mass) of polyphenols in the composition, L represents the content (% by mass) of lecithin in the composition, and F represents the content (% by mass) of fats and oils in the composition.

[0045] In formula (1), if the value of F / L is too small or too large, that is, if the amount of fat or oil relative to the amount of lecithin contained in the composition is too small or too large, the emulsion stability of the composition decreases.

[0046] In addition, in formula (1), F / L is preferably greater than 20. This makes it possible to obtain better water resistance.

[0047] In formula (2), if the F / P value is too small, the water resistance of the waterproof paper coated with the composition will decrease. On the other hand, if the F / P value is too large, the viscosity of the composition will be too high, making it impossible to properly apply the composition to the substrate. Furthermore, if the oil content is too high, for example, when cellulose cloth paper is used as the substrate, it will be difficult to impregnate the cellulose cloth paper with the composition. Furthermore, the oil will seep out of the waterproof paper, and if other papers are stacked on top of the waterproof paper when stored, the oil will be transferred to the other papers.

[0048] As with the above formulas (1) and (2), from the viewpoints of water resistance and appropriate application, F can be set to 2 to 50 mass %, L can be set to 0.05 to 6 mass %, and P can be set to 0.2 to 4 mass %, thereby providing the waterproof paper with excellent water resistance.

[0049] [Composition Variation 2] The composition may further contain casein. The casein may be isolated casein or a material containing casein. Examples of materials containing casein include milk, fermented milk products, processed milk products, etc. In addition, when producing the composition, at least one of milk, fermented milk products, processed milk products, etc. may be used as a material.

[0050] The composition may satisfy the following formulas (3) and (4): 10 <F / C<150 (3) 1.0 <F / P<70 (4) In formulas (3), (4) and formula (5) described below, P represents the content (% by mass) of polyphenols in the composition, C represents the content (% by mass) of casein in the composition, and F represents the content (% by mass) of fats and oils in the composition.

[0051] In formula (1), if the value of F / C is too small or too large, that is, if the amount of fat or oil relative to the casein contained in the composition is too small or too large, the emulsion stability of the composition will decrease.

[0052] In formula (2), if the value of F / P is too small, the water resistance of the waterproof paper coated with the composition will decrease, whereas if the value of F / P is too large, the viscosity of the composition will be too high, resulting in a decrease in the water resistance of the waterproof paper coated with the composition.

[0053] As with the above formulas (3) and (4), from the viewpoint of water resistance and appropriate application, C can be set to 0.05 to 6 mass % and P can be set to 0.2 to 4 mass %, thereby enabling waterproof paper coated with the composition to have excellent water resistance.

[0054] The composition can satisfy the following formula (5): L / C≧30 (3) This allows the waterproof paper to have better water resistance.

[0055] The composition may further contain other components in addition to polyphenols (tannins), fats and oils, lecithin (or casein), and vinegar, as necessary, to the extent that the effects of the present disclosure are not impaired. The other components are not particularly limited and may be appropriately selected from known components that can be incorporated into compositions. Examples include water, organic solvents, inorganic acid ammonium salts, metal salts, and additives (surfactants, water repellents, antifoaming agents, flame retardants, preservatives, antifungal agents, plasticizers, colorants, thickeners, bulking agents, etc.). These components may be used alone or in combination of two or more. From the viewpoint of improving affinity with the materials of the composition, the organic solvent preferably has an SP value of 10 or more. The viscosity of the composition can be reduced by using an organic solvent with an SP value of 10 or more.

[0056] The composition may further contain water to facilitate application or impregnation of the composition onto a substrate. That is, the composition may be a liquid composition in which polyphenols, oils and fats, and an emulsifier (lecithin or casein) are dissolved or dispersed in water.

[0057] The composition contains a large number of micelles. The large number of micelles have a volume-average particle size of 40 μm or less. This stabilizes the emulsion. From this perspective, the volume-average particle size of the micelles is preferably 40 μm or less, more preferably 20 μm or less. The lower limit of the volume-average particle size of the micelles is not particularly limited, but is preferably 0.1 μm or more. The volume-average particle size of the micelles is measured by light scattering using a HORIBA LA-920 (manufactured by HORIBA, Ltd.) laser diffraction / scattering particle distribution analyzer. The concentration of the liquid to be measured is adjusted so that the light transmittance does not exceed the measurement limit. Furthermore, the frequency of micelles with a particle size of 65 μm or more is 10% or less in terms of number. That is, the number of micelles with a particle size of 65 μm or more is preferably 10% or less, more preferably 2% or less, and more preferably 0.1% or less, of the total number of micelles. This improves the stability of the composition and makes it easier to manage the composition. The particle size of micelles is the sum of the percentage of particles 65 μm or larger in size from a particle size histogram measured by light scattering. Here, the volume-average particle size is the particle size calculated by the following formula, where di is the particle radius and ni is the number of particles. Σ(di 4 ×ni) / Σ(di 3 ×ni)

[0058] Furthermore, the waterproof paper bonded body disclosed herein can contribute to the achievement of Goal 7 "Affordable and clean energy" and Goal 12 "Responsible consumption and production" of the Sustainable Development Goals (SDGs) advocated by the United Nations.

[0059] Although the embodiments have been described above, the present disclosure is not limited to the above-described embodiments, and various modifications are possible without departing from the spirit of the present disclosure. [Example]

[0060] [Joint evaluation] Waterproof paper coated with a composition containing 2% or more by mass of oils and fats relative to the polyphenols and composition described above was prepared and cut into strips measuring 25 mm wide x 300 mm long to obtain waterproof test paper. The waterproof test paper was bonded to a target paper using the adhesive shown in Table 1 to prepare specimen 1. Specimens 2 to 5 were also prepared in the same manner, using different adhesive and other conditions as shown in Table 1. In Table 1, specimens 1, 2, and 4 are examples, and specimens 3 and 5 are comparative examples. Note that the present disclosure is not limited by the following description of the examples.

[0061] For each of specimens 1 to 5, the waterproof paper for the test was temporarily attached to the object to be joined by hand pressure, and then pressed back and forth with a 2 kg roller, followed by curing for 20 minutes. The bonded portions of specimens 1 to 5 thus obtained were manually peeled apart, and the degree of bonding was evaluated by visually observing the failure mode. Note that, as shown in the "Both Sides" column of the "Tape Substrate" in Table 1, when adhesive was applied to both sides of the tape substrate (double-sided tape), one side of the tape substrate was backed with a PET film.

[0062] [Table 1]

[0063] The criteria for the "failure mode" and "evaluation" shown in Table 1 are as follows: "Total destruction": The entire waterproof test paper was destroyed at the joint. In other words, the waterproof test paper sheets were well bonded together by the adhesive (evaluation A). "Partial destruction": The waterproof test paper was partially destroyed at the joint. In other words, the waterproof test paper sheets were bonded to some extent by the adhesive (evaluation B). "Interfacial failure": Peeling occurred between the waterproof test paper and the adhesive. In other words, the waterproof test papers were not sufficiently bonded together by the adhesive (evaluation C).

[0064] As shown in Table 1, specimens 1, 2, and 4 were rated "B" or higher. This means that specimens using adhesives with a glass transition temperature of -50°C to -10°C and an adhesive strength to SUS plates of 7 N / 10 mm or more can bond the waterproof test papers to a certain extent. Furthermore, of specimens 1, 2, and 4, specimen 2 was rated "A." This means that adhesives with an adhesive strength to SUS plates of 11.5 N / 10 mm or more can bond the waterproof test papers to each other more effectively. As mentioned above, adhesives with an adhesive strength to SUS plates of 7 N / 10 mm or more include, for example, styrene-isobutylene-styrene rubber (synthetic rubber (SIS-based)) or acrylic resin.

[0065] The adhesive strength of the adhesive to SUS plates was measured in accordance with JIS Z 0237 (2022) as follows. First, the adhesive for each of specimens 1 to 5 was applied to both sides of a tape substrate to prepare double-sided adhesive tapes measuring 25 mm wide and 300 mm long. Then, a PET film of the same size as the double-sided adhesive tape (within a 5% error from 25 mm wide and 300 mm long) and 19 μm thick was attached and pressed onto one side of each double-sided adhesive tape to prepare test specimens 1 to 5 corresponding to specimens 1 to 5. Each of specimens 1 to 5 was attached to a stainless steel plate (SUS304) and pressed against the plate using a 2000 g roller, which was moved back and forth at a speed of 5 mm / s. After leaving each of specimens 1 to 5 for 20 to 40 minutes, each of specimens 1 to 5 was peeled off at a speed of 5 mm / s in a direction 180° from the stainless steel plate using a tensile tester, and the adhesive strength to the stainless steel plate was measured. Here, "compression bonding" refers to a state in which, when each of the test pieces 1 to 5 is attached to the stainless steel plate, no air gets trapped between the stainless steel plate and each of the test pieces 1 to 5.

[0066] [Water resistance rating 1] Next, like the waterproof paper of the first modified example described above, waterproof paper further containing lecithin was used to evaluate the waterproofness of the waterproof paper.

[0067] In the following Tables 2 and 3, "composition (parts)" indicates parts by mass, and "composition (%)" indicates % by mass. Table 2 shows the parts by mass of the components contained in the compositions of each Example and Comparative Example, and Table 3 shows the mass % of the components contained in the compositions of each Example and Comparative Example and the test results.

[0068] (Materials used) Polyphenols: Mimasu Kashiwa Shoten's persimmon tannin paint Mayonnaise: Contains 7mL (6.5%) vinegar, 20g (18.7%) egg yolk, and 80mL (72.7%) vegetable oil. The mayonnaise was prepared as follows: First, the above ingredients were returned to room temperature, and half of the vegetable oil was gradually added to the egg yolk containing lecithin while mixing until the mixture became cloudy. Then, vinegar was added and mixed. Finally, the remaining half of the vegetable oil was gradually added and mixed to obtain the mayonnaise. Organic solvent: 2-propanol manufactured by Wako Pure Chemical Industries, Ltd. Drying oil: linseed oil manufactured by Ohta Oil Co., Ltd., perilla oil manufactured by Ohta Oil Co., Ltd.

[0069] In Table 3 below, P is the content (% by mass) of polyphenols relative to the composition, F is the content (% by mass) of fats and oils relative to the composition, and L is the content (% by mass) of lecithin relative to the composition. P was calculated assuming that the persimmon tannin paint contains 4.18% by mass of polyphenols. In Table 3 below, F was calculated assuming that the fats and oils contained in mayonnaise generally contain 72.7% fats and oils, and is the sum of linseed oil (F1) and perilla oil (F2) contained in this mayonnaise. L was calculated assuming that the mayonnaise lecithin (egg yolk lecithin) (L1) contained in mayonnaise generally contains 0.71% fats and oils, and is the sum of soybean lecithin (L2) and mayonnaise lecithin (L1). In addition, soybean lecithin (L2), linseed oil (F1), perilla oil (F2), and 2-propanol were calculated as having a concentration of 100%. Furthermore, in Tables 2 and 3, the numbers of carbon atoms in 2-propanol (C3) and peppermint oil (C10) indicate the respective numbers of carbon atoms.

[0070] [Table 2]

[0071] [Table 3]

[0072] [Preparation of Composition] (Examples 4 to 13 and 16 to 26) Persimmon tannin paint (polyphenols), mayonnaise, soybean lecithin, 2-propanol (organic solvent, containing three carbon atoms) or drying oil were placed in a sealed container in the parts by weight shown in Table 2 and dispersed and mixed by vigorously shaking for about 1 minute to prepare a liquid composition. In Examples 4 to 7, 10, 12, and 13, the ratio of mayonnaise to persimmon tannin paint is as shown in Tables 2 and 3. In Examples 4 to 6, 8 to 9, 11 to 13, and 16 to 26, the ratio of 2-propanol:IPA (organic solvent) to persimmon tannin paint was 75 to 100%.

[0073] Examples 14 and 15 In Examples 14 and 15, 2-propanol was not added, and mint oil was placed in a sealed container as the alcohol, and the mixture was dispersed and mixed in the same manner as above to prepare the composition. The mint oil has 10 to 40 carbon atoms.

[0074] [Measurement of particle size of composition] The particle size distribution of the micelles in the composition was measured using the light scattering method with the aforementioned HORIBA LA-920 (manufactured by Horiba, Ltd.). The results showed that the volume-average particle size of the micelles immediately after preparation was 40 μm or less, and the components separated over time. After dispersion and mixing, the proportion of particles 65 μm or larger was 10% or less, improving the stability of the composition. Here, the average particle size refers to the particle size (volume-average particle size) at which the cumulative number of particles in the particle size distribution reaches 50%.

[0075] [Sample preparation] In Examples 4 to 26, the composition was applied to a substrate of cellulose cloth paper (JK Wiper (registered trademark) 150S (manufactured by Nippon Paper Crecia Co., Ltd.)), impregnated tightly onto both sides of kraft paper, and heat-treated under the heat-treatment conditions shown in Table 3 to obtain samples impregnated with the composition.

[0076] (Comparative Examples 3 to 8) Basis weight approximately 50g / m 2 Kraft paper (unbleached, matte on both sides) (manufactured by Hokuetsu Corporation) was cut into a 15 cm x 15 cm square and its mass was measured. This kraft paper alone was used as the sample of Comparative Example 3.

[0077] In Comparative Examples 4 to 6, persimmon tannin paint containing polyphenols (Comparative Example 4), mayonnaise (Comparative Example 5), a mixture of mayonnaise and organic solvent (Comparative Example 6), and egg yolk (Comparative Example 8) were each impregnated into JK Wiper 150S (manufactured by Nippon Paper Crecia Co., Ltd.) in the formulations shown in Tables 2 and 3, and the paper was impregnated tightly onto both sides of kraft paper. Heat treatment was then performed under the heat treatment conditions shown in Table 3 to obtain samples impregnated with each component.

[0078] In Comparative Example 7, a persimmon tannin paint containing polyphenols was impregnated into JK Wiper 150S (manufactured by Nippon Paper Crecia Co., Ltd.) as a base, with the formulations shown in Tables 2 and 3, and impregnated tightly onto both sides of kraft paper, followed by heat treatment under the conditions shown in Table 3 to obtain a sample impregnated with the persimmon tannin paint. Subsequently, drying oil and organic solvent were impregnated in the same manner as the top layer, and heat treatment was again performed under the conditions shown in Table 3 to obtain a sample impregnated with the drying oil and organic solvent.

[0079] The mass of each sample was measured, and the solid application amount of the composition impregnated into the kraft paper was calculated from the measured mass using the following formula. Composition (g) = BA Here, "A" indicates the mass (g) of the kraft paper before impregnation, and "B" indicates the mass (g) of the sample impregnated with the composition after heat treatment. Note that in Comparative Example 2, the solid composition application amount was negative because the amount of water contained in the kraft paper that had evaporated was large even before the composition was applied.

[0080] [Evaluation of water absorption] The water absorption of the prepared samples was evaluated by the following procedure. The mass of each sample, measuring 150 mm x 150 mm, was measured. A Pax Naturon (registered trademark) kitchen sponge manufactured by Taiyo Yushi was cut into a 6 cm x 10.5 cm x 3 cm piece using a cutter. Once fully saturated with water, it was placed on the center of the sample surface and left for 60 minutes. After 60 minutes, the sponge was removed, and the sample was wiped dry with a white Kimtowel (registered trademark) folded in four (manufactured by Nippon Paper Crecia Co., Ltd.). Any remaining water droplets on the sample surface were then wiped away with another Kimtowel to ensure no water droplets remained on the sample surface. The mass of the wiped sample was measured, and the difference in mass before and after placing the sponge was taken as the water absorption. The results are shown in Table 3. The lower the water absorption, the better the water resistance of the sample.

[0081] [Evaluation of oil transfer] The prepared samples were evaluated for the state of oil transfer as follows. First, the sample was sandwiched between two sheets of kraft paper made of virgin pulp, and a 10 cm square metal plate was placed on top of it. A weight was then placed on top of that, and the sample was then placed at a 10 cm 2 The sandwiched kraft paper was then visually inspected to see if oil had soaked into it and formed stains. If stains had formed on the kraft paper, the oil transfer was evaluated as "present."

[0082] [Evaluation of paint stability] The stability of the compositions (paints) was evaluated as follows. First, after preparing the compositions, they were left as is for 24 hours. If the composition separated into two layers or precipitated after that, it was deemed unstable and rated "C." If the apparent viscosity increased without clear separation such as precipitation and the viscosity decreased upon further stirring, it was rated "B." If the composition remained uniformly dispersed without separating into two layers, i.e., remained in an emulsion state, it was deemed stable and rated "A."

[0083] [Evaluation of the appearance of waterproof paper] The prepared samples were evaluated as "uneven" if color unevenness due to the impregnated composition was clearly visible, and as "uniform" if not.

[0084] [Water repellency evaluation] The water repellency of the prepared samples was tested based on the old JIS standard (JIS P8137), and samples rated R9 and R10 in the standard were rated "A," while others were rated "B."

[0085] The water absorption amounts of Examples 4 to 6, in which a composition containing persimmon tannin paint (polyphenols), mayonnaise (oil, egg yolk, and vinegar), and an organic solvent was applied, and the water absorption amount of Example 7, in which a composition containing persimmon tannin paint and mayonnaise was applied, were lower than that of Comparative Example 3, in which only kraft paper was used, confirming improved water resistance. Similarly, improved water resistance was confirmed in Example 8, in which a persimmon tannin paint, soybean lecithin, an organic solvent, and a drying oil were applied. The water absorption amounts of Comparative Examples 4 to 7, in which a composition lacking either persimmon tannin paint (polyphenols), mayonnaise (egg yolk lecithin), soybean lecithin, or a drying oil was applied, were lower than those of Comparative Example 3 but higher than those of Examples 4 to 9. In Comparative Example 7, the persimmon tannin paint and the drying oil separated, so the composition had to be applied twice: once to apply the persimmon tannin paint and once to apply the drying oil. This suggests that lecithin prevents the composition from separating. Furthermore, the water absorption amount of Comparative Example 8, which contained only egg yolk as a composition, was approximately the same as that of Comparative Example 3. From the above, it was confirmed that the water absorption amount of waterproof paper can be significantly reduced by using a composition containing polyphenols contained in persimmon tannin paint and either egg yolk lecithin or soybean lecithin and fats and oils.

[0086] Furthermore, comparing Examples 4 to 6, the longer the drying time, the lower the amount of water absorption. However, even in Examples 6 to 9, which had a relatively short drying time, the amount of water absorption was still significantly lower than in the comparative examples. That is, the evaluation of Examples 4 to 6 confirmed that it was possible to produce water-resistant cellulose fabric paper with excellent water resistance while shortening the production period. Furthermore, comparing Examples 4 to 26, when the F / L value exceeded 20, the amount of water absorption tended to decrease significantly. In other words, the water resistance tended to improve significantly. Therefore, in formula (1), it was found that better water resistance could be obtained if the F / L value was greater than 20.

[0087] Furthermore, in Examples 4 to 26, the above-mentioned "oil transfer," "stability of the coating (composition)," and "appearance of the waterproof paper" were evaluated.

[0088] As a result, in the "oil transfer" test, oil transfer was "yes" in Examples 13 and 26, while oil transfer was "no" in the other Examples. That is, Examples 13 and 26 contained relatively high amounts of oil and fat components such as mayonnaise or perilla oil. In other words, it is thought that the F / P value became too large, causing the viscosity to increase and preventing proper impregnation of the composition, resulting in oil transfer. Therefore, it was confirmed that it is best to set the F / P value in formula (2) to be less than 25. It is possible to dilute the composition with water to properly impregnate it, but this is thought to reduce the water repellency due to the reduced polyphenol content P.

[0089] Next, the "stability of the paint" was evaluated. As a result, the evaluation was "B" in Examples 20, 21, 24, and 25, and "A" in the other examples. In Examples 21, 24, and 25, the F / L value was too small, that is, the lecithin content was too low, so it is considered that the stability of the paint was evaluated as "B". Also, in Example 20, the F / L value was too large, that is, the lecithin content was too high, so it is considered that the stability of the paint was evaluated as "B". Therefore, from the viewpoint of ensuring the stability of the paint, it was confirmed that the F / L value should be greater than 5 and less than 150. That is, it was found that the composition can ensure the stability of the paint by satisfying the formula (1) "5 < F / L < 150".

[0090] Next, the "appearance of the water-resistant paper" was evaluated. As a result, it was "non-uniform" in Examples 14, 15, 17, 21, 24, and 25, and no color unevenness due to the composition was visually observed in the other examples. In Example 14, "peppermint oil" was used as the organic solvent instead of 2-propanol. In Example 14, although sufficient water resistance could be obtained, it is considered that the "appearance of the water-resistant paper" became non-uniform because the viscosity increased. Also, in Example 15, although it became easier to penetrate compared to Example 14 by diluting twice with water, the "appearance of the water-resistant paper" was non-uniform. When 2-propanol was used, excellent water resistance could be obtained even when diluted four times with water. In Example 17, the viscosity increased because the content of 2-propanol was relatively low, and the "appearance of the water-resistant paper" was non-uniform because the invasiveness of the paint into the kraft paper was low due to the small amount of the oil component. Also, in Examples 21, 24, and 25, the viscosity increased because the lecithin content was too high, and the "appearance of the water-resistant paper" was non-uniform. Therefore, the contents of 2-propanol, peppermint oil, and lecithin are considered to affect the "appearance of the water-resistant paper".

[0091] Next, the "water repellency" was evaluated. As a result, in Examples 4 to 26, excellent water repellency could be obtained. That is, in Examples 4 to 26, the F / P values were all greater than 1.0. Thus, considering the above evaluation of "oil transfer" as well, it was found that by satisfying the formula (2) "1.0 < F / P < 25", the water repellency can be improved and the composition can be appropriately impregnated into the substrate.

[0092] Here, the content P of polyphenols can be determined as follows. First, 550% ethanol is added to 0.2 to 0.6 g of a sample of the composition, followed by ultrasonic irradiation and centrifugation. Then, it is filtered to obtain a test solution. Also, 1 mL of a catechin standard solution is prepared. For the catechin standard solution, 0.5 mL of Folin-Ciacalteu reagent and 5 mL of 0.4 mol / L aqueous sodium carbonate solution are added, and after leaving it standing for 25 minutes in an environment at 30 °C, the content P of polyphenols is specified by measuring at a wavelength of 660 nm using an ultraviolet-visible spectrophotometer. The catechin standard solution is a standard sample composed of (+)-catechin dissolved and diluted in water. More specifically, 10 mg of (+)-catechin is weighed and placed in a 10 mL volumetric flask. Then, it is made up to 10 mL with methanol to obtain a 1000 ppm standard sample. 400 μL of purified water is added to this standard sample to prepare a 100 ppm catechin standard solution.

[0093] The lecithin content (L) can be determined using the following method. First, a 2:1 mixture of chloroform and methanol is added to 1.2 g of a sample of the composition to obtain a mixed solution. Next, the mixed solution is centrifuged, and 100 mL of the 2:1 mixture of chloroform and methanol is added to the precipitate, mixed thoroughly, and centrifuged. 20 mL of the 2:1 mixture of chloroform and methanol is added to the solid fraction, and centrifuged again. 93 mL of 0.99% potassium chloride solution is added to the entire upper layer obtained by this centrifugation, and the mixture is left overnight. The mixture is then dehydrated and filtered, and the solvent is removed by evaporation. 50 mL of chloroform is added, mixed, and 5 mL of an aliquot is taken. After removing the solvent, 0.5 g of magnesium nitrate is added, and the mixture is decomposed at 550°C for 16 hours. 5 mL of 6 mol / L hydrochloric acid solution is added, and 50 mL of constant volume water is added, mixed uniformly, and 20 mL of an aliquot is taken. After neutralizing this, 5 mL of molybdenum blue coloring reagent, 1 mL of 5% ascorbic acid solution, and 50 mL of water are added to develop color, and the absorbance is measured at a wavelength of 710 nm for quantification.

[0094] The fat and oil content F can be determined by the following method. First, a solvent with a molecular structure without CH groups, such as carbon tetrachloride or trichlorotrifluoroethane, is added to a sample of the composition to separate the oil component from non-oil components such as water. Then, a calibration curve is created from the absorbance of the infrared spectrum using an OCB mixed standard substance, and the fat and oil content F is quantified by comparing the absorbance of the sample with the calibration curve.

[0095] For each of Examples 4 to 26, the same bonding evaluation was carried out as for Specimens 1, 2, and 4 (Examples 1 to 3) shown in Table 1. That is, specimens were prepared using an adhesive having a glass transition temperature of -50°C to -10°C and an adhesive strength to SUS plate of 7 N / 10 mm or more, and the same test as above was carried out. As a result, the failure mode in all of Examples 4 to 26 was "total failure" or "partial failure." Note that the adhesive used in each of Examples 4 to 26 was at least one of styrene-isobutylene-styrene rubber (synthetic rubber (SIS-based)) or acrylic resin.

[0096] [Water resistance rating 2] Furthermore, the water resistance of waterproof paper further containing casein, like the waterproof paper of the second modified example, was evaluated.

[0097] In the following Tables 4 and 5, "composition (parts)" indicates parts by mass, and "composition (%)" indicates % by mass. Table 4 shows the parts by mass of the components contained in the compositions of each Example and Comparative Example, and Table 5 shows the mass % of the components contained in the compositions of each Example and Comparative Example and the test results.

[0098] (Materials used) Polyphenols: Mimasu Kashiwa Shoten's persimmon tannin paint Milk: Rich and delicious milk manufactured by Ezaki Glico Co., Ltd. (Examples 27 to 31, Comparative Examples 9 to 12), milk rich in calcium and iron manufactured by Ezaki Glico Co., Ltd. (Examples 32 to 41) Organic solvent: 2-propanol manufactured by Wako Pure Chemical Industries, Ltd., ethanol (95) manufactured by Wako Pure Chemical Industries, Ltd., peppermint oil P manufactured by Kenei Pharmaceutical Co., Ltd. Drying oil: linseed oil manufactured by Ohta Oil Co., Ltd., perilla oil manufactured by Ohta Oil Co., Ltd.

[0099] In Table 5 below, P is the content (mass%) of polyphenols in the composition, F is the content (mass%) of fats and oils in the composition, and C is the content (mass%) of casein in the composition. P was calculated assuming that the persimmon tannin paint contains 4.18 mass% of polyphenols. F is the content (mass%) of fats and oils contained in milk in Table 5 below. m ) per 200 mL (Examples 27 to 31, Comparative Examples 9 to 12) and 2.3 g per 200 mL (Examples 32 to 41). d) is added together. C was calculated by calculating the total protein content (mass%) in milk, based on the total protein content in milk being 6.8 g per 200 mL (Examples 27 to 31, Comparative Examples 9 to 12) and 3.3 g per 200 mL (Examples 32 to 41), and assuming that casein generally accounts for 80% of the total protein content (mass%) in the obtained milk. In addition, when perilla oil or flaxseed oil (F d ), and 2-propanol, etc. were calculated assuming a concentration of 100%.

[0100] [Table 4]

[0101] [Table 5]

[0102] [Preparation of Composition] (Examples 27 to 30 and 32 to 39) Persimmon tannin paint (polyphenols), perilla oil, milk, 2-propanol (organic solvent, having three carbon atoms), and drying oil were placed in a sealed container in the parts by weight shown in Table 4, and the mixture was dispersed and mixed by vigorously shaking for about 1 minute to prepare a liquid composition. In Examples 27 to 30 and 32 to 39, the ratio of milk to persimmon tannin paint is as shown in Tables 4 and 5. In Examples 27 to 30 and 32 to 39, the ratio of 2-propanol:IPA (organic solvent) to persimmon tannin paint was 50%.

[0103] Example 31 In Example 31, the composition of Example 1 and 250 parts by mass of water were sealed in a sealed container and dispersed and mixed in the same manner as above to prepare a composition.

[0104] Examples 40 and 41 In Example 40, ethanol was placed in a sealed container as the alcohol without adding 2-propanol, and the compositions were prepared by dispersing and mixing in the same manner as described above. In Example 40, ethanol was placed in a sealed container, and in Example 41, 2-propanol and ethanol were placed in a sealed container in the parts by mass shown in Table 4, and the compositions were prepared by dispersing and mixing in the same manner as described above. Note that ethanol has two carbon atoms, and peppermint oil has 10 to 40 carbon atoms.

[0105] (Comparative Example 9) In Comparative Example 9, perilla oil was not added, and the persimmon tannin paint, milk, and 2-propanol were sealed in a sealed container in the parts by mass shown in Table 4, and the composition was prepared by dispersing and mixing in the same manner as above. That is, the composition was prepared so that F shown in Table 5 was less than 2 mass%.

[0106] (Comparative Example 10) In Comparative Example 10, no persimmon tannin paint was added, and milk, 2-propanol, and perilla oil were sealed in a sealed container in the parts by mass shown in Table 4, and dispersed and mixed in the same manner as above to prepare a composition. In other words, the composition of Comparative Example 10 does not contain polyphenols (P).

[0107] (Comparative Example 11) In Comparative Example 11, perilla oil and 2-propanol were not added, and the persimmon tannin paint and milk were sealed in a sealed container in the parts by mass shown in Table 4, and the composition was prepared by dispersing and mixing in the same manner as above. That is, the composition was prepared so that F shown in Table 5 was less than 2 mass%.

[0108] (Comparative Example 12) In Comparative Example 12, milk and perilla oil were placed in a sealed container in the parts by mass shown in Table 4 without adding persimmon tannin paint or 2-propanol, and the mixture was dispersed and mixed in the same manner as described above to prepare a composition. That is, the composition of Comparative Example 12 does not contain polyphenols (P).

[0109] [Measurement of particle size of composition] The method for measuring the particle size of the composition is as described above.

[0110] [Sample preparation] In Examples 27 to 41 and Comparative Examples 9 to 12, the composition was applied to a substrate of cellulose cloth paper (JK Wiper (registered trademark) 150S (manufactured by Nippon Paper Crecia Co., Ltd.)) measuring 150 mm x 150 mm, impregnated onto both sides of kraft paper without leaving any gaps, and heat treatment was performed under the heat treatment conditions shown in Table 5 to obtain samples impregnated with the composition.

[0111] [Evaluation of paint stability] The stability of the compositions (paints) was evaluated as follows. First, after preparing the compositions, they were left as is for 24 hours. If the composition separated into two layers or precipitated after that, it was deemed unstable and rated "C." If the apparent viscosity increased without clear separation such as precipitation and the viscosity decreased upon further stirring, it was rated "B." If the composition remained uniformly dispersed without separating into two layers, i.e., remained in an emulsion state, it was deemed stable and rated "A."

[0112] [Water repellency evaluation] The water repellency of the prepared samples was tested based on the old JIS standard (JIS P8137), and the water repellency of the samples was evaluated according to this standard.

[0113] Comparing Examples 27 to 41 with Comparative Examples 9 to 12, it was found that excellent water repellency could be obtained when polyphenols, fats and oils, and casein were included and the fat content F was 2% by mass or more. That is, Comparative Examples 9 and 11, in which the fat content F was less than 2% by mass, and Comparative Examples 9 and 12, which did not include polyphenols, were evaluated as "R0" for water repellency, and excellent water repellency could not be obtained. Thus, it was confirmed that sufficient water repellency could be obtained for a water-resistant substrate when polyphenols, casein, and fats and oils were included and the fat content F relative to the composition was 2% by mass or more. Furthermore, when casein was not included, the coating was unstable and water repellency could not be evaluated. From this, it is believed that casein is necessary to stabilize the coating.

[0114] Furthermore, in Examples 27 to 41, the above-mentioned "stability of the paint (composition)" and "water repellency" were evaluated.

[0115] First, the "stability of the paint" was evaluated. As a result, in Examples 32, 33, 37, and 38, the evaluation was "B", and in the other examples, the evaluation was "A". In Example 37, the F / C value was too small, that is, the content of casein was too low, so it is considered that the stability of the paint was evaluated as "B". Also, in Examples 32, 33, and 38, the F / C value was too large, that is, the content of casein was too high, so it is considered that the stability of the paint was evaluated as "B". In Example 38, the F / P value was too large, that is, the content of sesame oil was too high, so it is considered that the stability of the paint was evaluated as "B". In Example 38, the viscosity became too high compared to the compositions of Examples 32 and 33, so it is considered that this was the reason for the poor stability of the paint. Therefore, from the viewpoint of ensuring the stability of the paint, it was confirmed that the F / C value should be greater than 10 and less than 150, and the F / P value should be greater than 1.0 and less than 70. That is, it was found that the composition can ensure the stability of the paint by satisfying the formula (3) "10 < F / C < 70" and the formula (4) "1.0 < F / P < 70". Also, in Examples 40 and 41, alcohols other than 2-propanol were used, but since the evaluation was "A", it was confirmed that the paint is stable even when alcohols other than 2-propanol are used.

[0116] Next, the "water repellency" was evaluated. As a result, in Examples 27 to 41, in Examples 28 to 30, 34, and 39 where the F / C value was less than 30, the water repellency evaluation was "R8" or less. On the other hand, in the other examples where the F / C value was 30 or more, the water repellency evaluation was high, "R9" or more. From this, it was found that if the F / C value is 30 or more, that is, by satisfying the formula (3) "F / C ≧ 30", the water repellency can be further improved. Furthermore, by satisfying the above formulas (3), (4), and (5), more excellent paint stability and water repellency could be obtained.

[0117] Furthermore, the number of applications was limited to one for all coating materials, and the heat treatment time was shortened to one minute. From the above results, the present invention has provided a waterproof paper that can more easily impart excellent water resistance to substrates such as cellulose cloth paper.

[0118] Here, the polyphenol content P and the fat and oil content F are determined as described above.

[0119] Furthermore, methods for measuring the casein content C include methods that use antibodies, such as ELISA. These methods detect specific proteins. When determining the casein content C in a paint using ELISA, a sample can be prepared from the paint as follows: The paint is diluted with a buffer solution so that the alcohol concentration in the paint is 1% by mass or less. When diluting the paint, a buffer solution is added until the pH of the sample is around 7. The type of buffer solution is not particularly limited as long as it can bring the sample pH to around 7, but preferably a buffer solution with a pH range of 3 to 11, more preferably 4 to 10, and even more preferably 5 to 9 can be used. Specifically, phosphate buffer solutions such as PBS, glycine buffer solutions, Tris buffer solutions, borate buffer solutions, citrate buffer solutions, Good's buffer solutions, etc. can be used. The concentration of the buffer solution is not particularly limited as long as it can bring the sample pH to around 7, but for example, a concentration of 0.1 to 200 mM is preferred, and a concentration of 1 to 150 mM is more preferred. In the present invention, the buffer solution concentration refers to the concentration (mM) of the buffering agent contained in the buffer solution. Furthermore, a sample with a pH of around 7 refers to a pH of 7.2 to 7.4. The sample is preferably diluted to a casein concentration of 10 to 1000 μg / L. If the casein concentration of the sample needs to be 1 / 1000 or less of that of the paint, serial dilution is preferred.

[0120] Furthermore, when using milk, the casein content C can be determined simply by measuring the total nitrogen content to determine the total protein content, and then confirming that 80% by mass of the protein determined by LC-MS is casein. It is also possible to separate and measure proteins using various LCs.

[0121] For each of Examples 27 to 41, the same bonding evaluation was carried out as for Specimens 1, 2, and 4 (Examples 1 to 3) shown in Table 1. That is, specimens were prepared using an adhesive having a glass transition temperature of -50°C to -10°C and an adhesive strength to SUS plate of 7 N / 10 mm or more, and the same test as above was carried out. As a result, the failure mode in all of Examples 27 to 41 was "total failure" or "partial failure." Note that the adhesive used in each of Examples 27 to 41 was at least one of styrene-isobutylene-styrene rubber (synthetic rubber (SIS type)) or acrylic resin. [Explanation of symbols]

[0122] 1 waterproof paper joint, 2 waterproof paper, 3 joint object, 4 joint member, 31 tape substrate, 32 adhesive

Claims

1. a first waterproof paper coated with a composition containing oils and polyphenols; A joining object to be joined to the first waterproof paper; a joining member that joins the first waterproof paper and the joining object, The content of the oil / fat in the composition is 2% by mass or more, the joining member includes an adhesive, The adhesive includes a base polymer having a glass transition temperature of −50° C. to −10° C., A waterproof paper joint, wherein the adhesive strength of the pressure-sensitive adhesive to SUS plate measured in accordance with JIS Z 0237 (2022) is 7 N / 10 mm or more.

2. The waterproof paper bonded body according to claim 1, A waterproof paper bonded body, wherein the object to be bonded is a second waterproof paper coated with the composition.

3. The waterproof paper bonded body according to claim 1, The adhesive strength of the adhesive to SUS plate is 11.5 N / 10 mm or more.

4. The waterproof paper bonded body according to claim 1, The waterproof paper bonded body, wherein the base polymer contains at least one of styrene-isobutylene-styrene rubber and acrylic resin.

5. The waterproof paper bonded body according to claim 1, The adhesive contains an additive, A waterproof paper bonded body, wherein the base polymer is contained in the adhesive in an amount of 96 mass % or more relative to the sum of the base polymer and the additive.

6. The waterproof paper bonded body according to claim 1, The composition further contains lecithin, and the waterproof paper bonded body satisfies the following formulas (1) and (2): 5<F / L<150 (1) 1.0<F / P<25 (2) In the above formulas (1) and (2), F represents the content (% by mass) of the oil or fat relative to the composition, L represents the content (% by mass) of the lecithin relative to the composition, and P represents the content (% by mass) of the polyphenols relative to the composition.

7. The waterproof paper bonded body according to claim 1, The composition further contains casein, and the waterproof paper bonded body satisfies the following formulas (3) and (4). 10<F / C<150 (3) 1.0<F / P<70 (4) In the above formulas (3) and (4), F represents the content (% by mass) of the oil or fat relative to the composition, C represents the content (% by mass) of the casein relative to the composition, and P represents the content (% by mass) of the polyphenols relative to the composition.

8. The waterproof paper bonded body according to claim 1, The oil and fat has an iodine value of 130 to 250.

9. The waterproof paper bonded body according to claim 1, The waterproof paper bonded body, wherein the polyphenols are at least one of tannins and flavonoids.

10. The waterproof paper bonded body according to any one of claims 1 to 9, the joining member is an adhesive tape, The adhesive tape is a waterproof paper bonded body comprising a tape substrate and the adhesive applied to at least one main surface of the tape substrate.

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