Paper treatment agent and paper using same, and method for improving paper texture

Abstract

Provided are a paper treatment agent that: can impart, to paper provided with moisture retention properties, a specific texture that matches a user's taste; brings about little change in moisture content in the paper between when the paper is in a high-humidity environment and when the paper is in a low-humidity environment; and can suppress moisture evaporation from paper even in a low-humidity environment; paper using such paper treatment agent; and a method for improving the texture of paper. The paper treatment agent of the present invention contains (A) polyhydric alcohol, (B) sulfonate, and (C) water, wherein the sulfonate (B) is contained therein in an amount from 0.05% by mass to less than 8.0% by mass relative to the total amount excluding water.

Description

Paper treatment agent, paper using the same, and method for improving paper texture

[0001] The present invention relates to a paper treating agent, paper using the same, and a method for improving the texture of paper.

[0002] Paper products such as toilet paper and facial tissues are required to have a soft and moist texture, and papers treated with paper treatment agents containing moisturizing components, such as moisturizing tissues with a soft texture, are widely used throughout the year. Paper products such as moisturizing tissues are coated with a paper treatment agent containing a polyhydric alcohol such as glycerin to impart flexibility. This flexibility is achieved by reducing pulp-to-pulp hydrogen bonds due to an increase in the moisture content of the coated paper. Therefore, problems arise such as paper tearing due to a reduction in paper strength in high-humidity environments and texture deterioration in low-humidity environments, and there is a demand for papers such as moisturizing tissues that are less dependent on humidity environments.

[0003] Furthermore, among papers treated with paper treatment agents containing moisturizing ingredients, moisturizing tissues are often used for blowing noses, and there is a demand for products with a good texture, such as reduced surface friction, to reduce the burden on the skin. It is desirable that papers with moisturizing properties be given a texture that suits the user's preferences as a commercial product.

[0004] Various approaches have been taken to address the technical challenges of imparting softness with low humidity dependency and improving texture. For example, Patent Document 1 proposes a fiber web product comprising a fiber web containing a hydrous gel composition. However, uniform application of the gel composition, which is already in a gel state before application, to paper involves complex processes, and the gel composition is difficult to transfer. Patent Document 2 attempts to improve moisturization by utilizing the water-absorbing properties of hydrophilic polymers. However, the time and effort required for uniform dispersion of hydrophilic polymers complicates the manufacturing process of paper treatment agents, and the hydrophilic polymers cause significant thickening. As a result, the amount of hydrophilic polymer must be limited, and sufficient effectiveness has not been achieved. Patent Document 3 proposes the use of oily substances and water-soluble waxes to impart softness and reduce friction, but the high viscosity of the water-soluble waxes impairs the fluidity and uniform application of the paper treatment agent, resulting in problems such as poor operability.

[0005] Patent Documents 4 and 5 disclose blending glycerin with a branched alcohol or a sucrose fatty acid ester to improve softness and texture in low-humidity environments. These bases have the advantage of being easily blended into moisturizers, and can contribute to maintaining softness in low-humidity environments, but the effect is insufficient.

[0006] Patent Documents 6 to 9 describe sulfonates as surfactants to be incorporated into paper treatment agents.

[0007] JP 2003-199685 A JP 2009-263837 A JP 10-226986 A JP 2007-107173 A JP 2016-074999 A JP 2019-099938 A JP 2019-157307 A JP 2008-073118 A JP 2010-265562 A

[0008] However, in Patent Documents 6 to 8, sulfonates are described in the examples as optional components or as components arbitrarily selected from multiple types of surfactants, but the amount of sulfonate added is not examined, and the specific formulations disclosed contain a large amount of sulfonate, making it difficult to impart the characteristic softness of coreless texture to paper, and also causing problems such as the paper treatment agent losing its fluidity and becoming hard.Patent Document 9 describes sulfonates as optional components selected from surfactants, but the specific formulations disclosed that contain sulfonates do not contain water, making it difficult to impart the characteristic texture, and also causing problems such as deterioration of texture in low-humidity environments.

[0009] The present invention has been made in consideration of the above circumstances, and aims to provide a paper treatment agent that can impart a unique texture that suits the user's preferences to paper that has been given moisture retention properties, that minimizes the change in moisture content of paper between high and low humidity environments, and that can suppress moisture evaporation from paper even in low humidity environments, as well as paper that uses the same and a method for improving the texture of paper.

[0010] To solve the above problems, the present inventors conducted extensive research and found that a paper treatment agent containing a polyhydric alcohol, a sulfonate salt, and water in specific ranges can impart a unique, silky, slippery texture to paper. Furthermore, the inventors surprisingly found that the agent can impart a coreless softness to paper, minimize changes in the moisture content of paper between high- and low-humidity environments, and inhibit moisture evaporation from paper even in low-humidity environments, leading to the completion of the present invention. Here, the unique, silky, slippery texture refers to a slippery feeling, as if touching gel. Specifically, the paper treatment agent of the present invention is characterized by containing (A) a polyhydric alcohol, (B) a sulfonate salt, and (C) water, with the content of the (B) sulfonate salt being 0.05% by mass or more and less than 8.0% by mass, based on the total weight excluding water. The paper of the present invention is characterized by being treated with the paper treatment agent. The method for improving the texture of paper of the present invention is characterized by treating with the paper treatment agent.

[0011] The paper treatment agent of the present invention is formulated by blending a specific amount of (B) sulfonate with an (A) polyhydric alcohol and further blending (C) water, and by this, in particular, the specific combination of the specific amounts of (B) sulfonate and (C) water, imparts a unique silky, slippery feel and coreless softness to paper, and further, the change in the moisture content of paper between high and low humidity environments is small, and moisture evaporation from paper can be suppressed even in low humidity environments. Furthermore, by blending a specific amount of (B) sulfonate with an (A) polyhydric alcohol and further blending (C) water, in particular, the specific combination of the specific amounts of (B) sulfonate and (C) water, the moisture of the paper treatment agent of the present invention is appropriately retained on the coated paper, pulp swelling is suppressed compared to conventional paper treatment agents, and coreless softness can be imparted thereby. This softness is achieved not only by blocking hydrogen bonds between pulp particles due to moisture, but also by moderately weakening the paper by suppressing pulp swelling, so paper treated with the paper treatment agent of the present invention has low dependency on humidity. Because of its softness that is low dependency on moisture, paper treated with the paper treatment agent of the present invention feels soft but does not lose paper strength and is less likely to tear. The paper treatment agent of the present invention suppresses moisture evaporation from paper even in low-humidity environments. Therefore, deterioration of texture in low-humidity environments is less likely to occur.

[0012] According to the present invention, it is possible to impart a unique silky, slippery texture and a coreless softness to paper to which moisture-retaining properties have been imparted, and further, there is little change in the moisture content of paper in high-humidity and low-humidity environments, and moisture evaporation from paper can be suppressed even in low-humidity environments. These effects are remarkable and exceed the range of effects that a person skilled in the art could have predicted from the configuration of the present invention.

[0013] The present invention will be described in detail below. In the present invention and the following description, the term "feel" particularly includes a characteristic silky slippery feel and a flat feel with little fluffiness, which reduces the burden on the skin and evokes a feeling of gentleness to the skin, and a soft, solid feel.

[0014] (Paper Treatment Agent) The paper treatment agent of the present invention essentially comprises (A) a polyhydric alcohol, (B) a sulfonate, and (C) water.

[0015] (A) Polyhydric Alcohol In the paper treating agent of the present invention, the polyhydric alcohol as component (A) is a moisturizing agent that enhances the moisture absorption and moisture retention of paper, imparting a moist feel and softness to the paper.

[0016] The polyhydric alcohol of component (A) is not particularly limited, but examples thereof include glycerin, diglycerin, triglycerin, polyglycerin, 1,2-propanediol, 1,3-propanediol, dipropylene glycol, polypropylene glycol, 1,3-butanediol, 1,4-butanediol, 1,2-pentanediol, 1,2-hexanediol, ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, polyoxyethylene glycerin ether, isoprene glycol, pentaerythritol, trimethylolpropane, etc. Sugar alcohols and saccharides may also be used, and examples of sugar alcohols include sorbitol, inositol, glucosyl trehalose, xylitol, erythritol, mannitol, lactitol, fructose, oligosaccharide alcohols, maltitol, reduced palatinose, reduced starch syrup, reduced starch hydrolysates, etc. Examples of sugars include fructose, glucose, lactose, xylose, psicose, maltose, starch syrup, oligosaccharides, maltose, trehalose, lactose, palatinite, sucrose, isomerized sugars, isomaltooligosaccharides, fructooligosaccharides, galactooligosaccharides, xylooligosaccharides, lactoferrin oligosaccharides, soybean oligosaccharides, raffinose, stevia, licorice, saccharin, aspartame, acesulfame K, and sucralose. These may be used alone or in combination of two or more. Among these, glycerin, 1,3-butanediol, 1,2-propanediol, and sorbitol are preferred, with glycerin being more preferred.

[0017] The content of (A) polyhydric alcohol is not particularly limited, but may be, for example, 1% by mass or more based on the total amount of the paper treatment agent excluding water. From the viewpoint of improving the texture of the paper coated with (A) polyhydric alcohol by moisture absorption, the content is preferably 50% by mass or more based on the total amount of the paper treatment agent excluding water, more preferably 70% by mass or more, even more preferably 80% by mass or more, particularly preferably 85% by mass or more, and most preferably 90% by mass or more. Furthermore, from the viewpoint of improving the texture specific to the present invention, the content is preferably 99.5% by mass or less based on the total amount excluding water, more preferably 98% by mass or less.

[0018] (B) Sulfonate In the paper treatment agent of the present invention, the sulfonate salt of component (B) is blended with (A) polyhydric alcohol in a specific range of amounts, and further blended with (C) water, to impart a unique silky, slippery feel and coreless softness to paper, and further minimizes the change in moisture content of paper in high-humidity and low-humidity environments, suppressing moisture evaporation from paper even in low-humidity environments. (B) Sulfonate salt has one or more sulfonate structures (-SO3X), preferably having a hydrophobic group and a hydrophilic group, and has surface activity due to the hydrophilic group being a sulfonate structure (-SO3X). The hydrophobic group preferably contains an alkyl group.

[0019] The number of carbon atoms in the alkyl group of the sulfonate is not particularly limited, but may be, for example, 4 to 30 (C4 to C30). From the viewpoint of improving the unique silk-like slippery feel and coreless softness, particularly the unique silk-like slippery feel, the number of carbon atoms in the alkyl group is preferably 8 or more, more preferably 10 or more, even more preferably 14 or more, and particularly preferably 16 or more. From the viewpoint of facilitating solubility in polyhydric alcohols and making it easier to exhibit the effects of the present invention, the number of carbon atoms in the alkyl group is preferably 26 or less, more preferably 24 or less, even more preferably 22 or less, and particularly preferably 18 or less. Here, the number of carbon atoms in the alkyl group represents an integer. These alkyl groups may be either unsaturated or saturated, and may be either linear or branched.

[0020] The sulfonate salt of component (B) used in the present invention is not particularly limited, but examples thereof include alkyl sulfonates, alkyl benzene sulfonates, alkyl naphthalene sulfonates, sulfosuccinate ester salts, sulfofatty acid ester salts, α-olefin sulfonates, alkyloyl alkyl taurine salts, and sodium coconut oil fatty acid methyl taurate. These may be used alone or in combination of two or more. Among these, from the viewpoint of exerting the effects of the present invention, alkyl sulfonates, alkyl benzene sulfonates, sulfosuccinate ester salts, and sulfofatty acid ester salts are preferred, and alkyl sulfonates, alkyl benzene sulfonates, and sulfosuccinate ester salts are more preferred.

[0021] The counter cation of the sulfonate anion in (B) the sulfonate salt is not particularly limited, but examples thereof include alkali metal ions such as sodium ion and potassium ion.

[0022] The content of (B) sulfonate is 0.05% by mass or more and less than 8.0% by mass of the total amount of the paper treatment agent excluding water, but from the viewpoint of improving the unique silky slippery feel and coreless softness, it is preferably 0.1% by mass or more, more preferably 0.2% by mass or more, even more preferably 0.4% by mass or more, still more preferably 0.7% by mass or more, even more preferably 1.5% by mass or more, and particularly preferably 2.0% by mass or more. Also, from the viewpoint of improving the fluidity of the paper treatment agent, it is preferably 7.9% by mass or less, more preferably 6.0% by mass or less, and even more preferably 5.0% by mass or less, of the total amount of the paper treatment agent excluding water.

[0023] In the paper treatment agent of the present invention, the mass ratio of the sulfonate (B) to the polyhydric alcohol (A) (component (B) / component (A)) is preferably 0.001 or more, more preferably 0.007 or more, even more preferably 0.015 or more, and particularly preferably 0.02 or more, from the viewpoint of improving the unique silk-like slippery feel and coreless softness. From the viewpoint of the fluidity of the treatment agent, it is preferably 0.085 or less, more preferably 0.07 or less, and even more preferably 0.053 or less.

[0024] (C) Water In the paper treatment agent of the present invention, the water (C) is an essential component that, in combination with the sulfonate (B), exerts the effects of the present invention. The water (C) is not particularly limited, but examples thereof include ion-exchanged water, tap water, and sterilized water.

[0025] The content of (C) water is not particularly limited, but may be, for example, 0.1 to 90% by mass relative to the total amount of the paper treatment agent. In consideration of the stability and viscosity of the paper treatment agent, it is preferably 1% by mass or more, more preferably 5% by mass or more, and even more preferably 8% by mass or more. In consideration of production efficiency and ease of viscosity adjustment depending on the type of coater, it is preferably 80% by mass or less, more preferably 50% by mass or less, and even more preferably 30% by mass or less.

[0026] (D) Other Components Other components (D) than those described above can be added as raw materials to the paper treatment agent of the present invention, as long as the effects of the present invention are not impaired. Examples of such other components include, but are not limited to, oily components, surfactants (nonionic surfactants, anionic surfactants other than component (B), cationic surfactants, and zwitterionic surfactants), moisturizing components other than component (A), thickeners, mildew inhibitors, preservatives, antifoaming agents, fragrances, colorants, pH adjusters, extracts, antioxidants, anti-inflammatory agents, inorganic minerals, inorganic salts, and water-soluble polymers. These may be used alone or in combination of two or more.

[0027] Oil-based components mainly improve the texture, such as the oily, moist feel and the surface feel (smoothness) of treated paper. Examples of oil-based components include hydrocarbons, oils and fats, esters, fatty acids, higher alcohols, silicone oils, waxes, and steroids. These may be used alone or in combination of two or more.

[0028] Examples of hydrocarbons include liquid paraffin, paraffin, solid paraffin, light isoparaffin, light liquid isoparaffin, liquid isoparaffin, ceresin, microcrystalline wax, petrolatum, squalane, polyethylene wax, polypropylene wax, hydrogenated polyisobutene, ethylene-α-olefin co-oligomer, and ethylene propylene polymer.

[0029] Examples of fats and oils include avocado oil, almond oil, linseed oil, olive oil, cacao oil, perilla oil, camellia oil, castor oil, sesame oil, wheat germ oil, rice germ oil, rice bran oil, sasanqua oil, safflower oil, soybean oil, evening primrose oil, camellia oil, corn oil, rapeseed oil, persic oil, palm kernel oil, coconut oil, palm oil, beef tallow, lard, horse fat, mutton tallow, shea butter, cacao butter, turtle oil, mink oil, egg yolk oil, Purcellin oil, castor oil, sunflower oil, jojoba oil, grapeseed oil, macadamia nut oil, cottonseed oil, meadowholm oil, coconut oil, peanut oil, cod liver oil, rosehip oil, hardened beef tallow oil, highly hardened beef tallow oil, hardened castor oil, and highly hardened palm oil.

[0030] Examples of esters include alkyl stearate, alkyl palmitate, alkyl myristate, alkyl laurate, alkyl behenate, alkyl oleate, alkyl isostearate, alkyl 12-hydroxystearate, alkyl undecylenate, alkyl lanolin fatty acid ester, alkyl erucate, alkyl coconut oil fatty acid ester, alkyl stearoyloxystearate, alkyl isononanoate, alkyl dimethyloctanoate, alkyl octanoate, alkyl lactate, alkyl ethylhexanoate, alkyl neopentanoate, alkyl malate, alkyl phthalate, alkyl citric acid, alkyl malonate, alkyl adipate, ethylene glycol fatty acid ester, propanediol fatty acid ester, butanediol fatty acid ester, trimethylolpropane fatty acid ester, pentaerythritol fatty acid ester, polyglycerin fatty acid ester, trehalose fatty acid ester, and pentylene glycol fatty acid ester.

[0031] Examples of fatty acids include stearic acid, palmitic acid, myristic acid, lauric acid, behenic acid, oleic acid, isostearic acid, 12-hydroxystearic acid, undecylenic acid, lanolin fatty acid, erucic acid, and stearoyloxystearic acid.

[0032] Examples of higher alcohols include lauryl alcohol, cetyl alcohol, cetostearyl alcohol, stearyl alcohol, oleyl alcohol, behenyl alcohol, lanolin alcohol, hexyldecanol, myristyl alcohol, arachyl alcohol, phytosterol, isostearyl alcohol, and octyldodecanol.

[0033] Examples of silicone oils include amino-modified silicone oil, epoxy-modified silicone oil, carboxyl-modified silicone oil, polyether-modified oil, polyglycerin-modified silicone oil, dimethylpolysiloxane, dimethylsilicone, polyether-modified silicone, methylphenylsilicone, alkyl-modified silicone, higher fatty acid-modified silicone, methylhydrogensilicone, fluorine-modified silicone, epoxy-modified silicone, carboxy-modified silicone, carbinol-modified silicone, amino-modified silicone, methylpolysiloxane, methylphenylpolysiloxane, silicone resin, dimethicone, methylhydrogenpolysiloxane, methylcyclopolysiloxane, octamethyltrisiloxane, tetramethylhexasiloxane, and highly polymerized methylpolysiloxane.

[0034] Examples of waxes include Japan wax, beeswax, hazelnut wax, urushi wax, sugarcane wax, palm wax, montan wax, carnauba wax, candelilla wax, rice bran wax, lanolin, spermaceti, reduced lanolin, liquid lanolin, hard lanolin, ceresin, ozokerite, etc. Examples of steroids include cholesterol, dihydrocholesterol, cholesterol fatty acid esters, etc.

[0035] Surfactants Among the surfactants, nonionic surfactants include, but are not particularly limited to, sorbitan fatty acid esters, polyoxyethylene sorbitan fatty acid esters, polyoxyethylene fatty acid esters, polyoxyethylene hydrogenated castor oil, polyoxyethylene castor oil, polyoxyethylene hydrogenated castor oil fatty acid esters, castor oil fatty acid esters, hydrogenated castor oil fatty acid esters, ethylene glycol fatty acid esters, sucrose fatty acid esters, glycerin fatty acid esters, diglycerin fatty acid esters, polyglycerin fatty acid esters, organic acid monoglycerides, polyethylene glycol fatty acid monoethanolamides, propylene glycol fatty acid esters, polyoxyethylene lanolin alcohol ethers, polyoxyethylene alkyl ethers, lauric acid alkanolamides, polyoxyethylene glycerin fatty acid esters, polyoxyethylene hydrogenated castor oil pyroglutamic acid fatty acid diesters, glyceryl pyroglutamate fatty acid, polyoxyethylene glyceryl pyroglutamic acid fatty acid diesters, and polyether-modified silicones.

[0036] Examples of anionic surfactants other than component (B) include, but are not limited to, sulfates, phosphates, carboxylates, etc. Examples of sulfates include, but are not limited to, alkyl sulfates, alkyl sulfate ester salts, alkyl ether sulfates, alkylamide sulfates, polyoxyethylene alkyl ether sulfates, etc. Examples of phosphates include, but are not limited to, phosphoric acid ester salts, alkyl ether phosphates, alkylamide phosphates, perfluoroalkyl phosphate esters, polyoxyethylene alkyl ether phosphates, alkyl phosphates, etc. Examples of carboxylates include, but are not limited to, fatty acid salts, N-acylamino acid salts (N-acyl-L-glutamic acid salts, N-acyl-L-arginine ethyl-DL-pyrrolidone carboxylate salts, etc.), alkyl ether carboxylates, polyoxyethylene alkyl ether acetates, etc.

[0037] The cationic surfactant is not particularly limited, but examples thereof include monoalkyltrimethylammonium salts, dialkyldimethylammonium salts, alkylpyridinium salts, N,N-dialkyloyloxyethyl-N-methyl,N-hydroxyethylammonium salts, alkylamine salts, and stearyldimethylbenzylammonium salts.

[0038] The amphoteric surfactant is not particularly limited, but examples thereof include alkyl betaine, fatty acid amidopropyl betaine, lauryl hydroxysulfobetaine, 2-alkyl-N-carboxymethyl-N-hydroxyethyl imidazolinium betaine, lecithin, hydrogenated lecithin, alkyloxyhydroxypropyl arginine hydrochloride, lauryl hydroxysultaine, lauriminodipropionic acid, undecylhydroxyethyl imidazolinium betaine sodium, sodium laurylaminodiacetate, lauryldimethylaminoacetic acid betaine, N-[3-alkyloxy-2-hydroxypropyl]-L-arginine hydrochloride, alkylhydroxysulfobetaine, alkyldimethylamine oxide, sodium alkylaminodipropionate, dihydroxyalkylmethylglycine, and sodium lauryldiaminoethylglycine.

[0039] The moisturizing component other than component (A) is not particularly limited, but can be exemplified by amino acids, hygroscopic alkalis and acids and their salts.As amino acids, can be exemplified by glycine, valine, leucine, isoleucine, serine, threonine, phenylalanine, arginine, lysine, aspartic acid, glutamic acid, cystine, cysteine, methionine, tryptophan, etc.As hygroscopic alkalis and acids and their salts, can be exemplified by trimethylglycine, betaine, pyrophosphate, sodium pyrophosphate, chondroitin sulfate, potassium pyrophosphate, hyaluronic acid, sodium hyaluronate, sodium metaphosphate, potassium polyphosphate, sodium pyrrolidone carboxylate, sodium lactate, sodium chloride, calcium chloride, sodium alginate, sodium polyacrylate, etc.These can be used alone or in combination of two or more.

[0040] The content of component (D) is preferably 90% by mass or less, more preferably 70% by mass or less, even more preferably 50% by mass or less, and particularly preferably 30% by mass or less, based on the total amount of the paper treatment agent excluding water.

[0041] The paper treating agent of the present invention can be produced by uniformly mixing the raw materials in accordance with a conventional method, for example, by stirring and mixing the raw materials at a temperature at which the raw materials dissolve.

[0042] The paper treatment agent of the present invention may be in a uniform mixture of components (A), (B), and (C), or, if component (D) is included, components (A), (B), (C), and (D), for example, in a molten state, a solubilized state, an emulsified state, or a dispersed state.

[0043] The paper treatment agent of the present invention contains components (A), (B), and (C), and thus exhibits low viscosity before application to paper and moderate moisture retention on the coated paper after application, thereby achieving the effects of the present invention. Because the paper treatment agent of the present invention has low viscosity, it is easy to transfer and handle, and the amount of treatment agent attached to the treated paper is easily controlled, resulting in good operability. The paper treatment agent, which affects the texture of the paper, also exhibits good uniform application to the paper. The paper treatment agent of the present invention preferably has a viscosity of less than 2000 mPa·s, and more preferably less than 500 mPa·s, as measured at 60 rpm and 40°C using a Brookfield viscometer. Furthermore, the paper treatment agent of the present invention maintains a uniform state over time and is highly stable. That is, the paper treatment agent has good stability over time and can maintain an appropriate viscosity over time.

[0044] A preferred example of the paper treating agent of the present invention is a paper treating agent that contains 50% by mass or more and 98% by mass or less of component (A) and 0.7% by mass or more and 7.9% by mass or less of an alkylsulfonate having an alkyl group having 12 to 26 carbon atoms as component (B), based on the total amount of the paper treating agent excluding water, and 5% by mass or more and 50% by mass or less of component (C), based on the total amount of the paper treating agent; or a paper treating agent that contains 50% by mass or more and 98% by mass or less of component (A) and 0.7% by mass or more and 7.9% by mass or less of an alkylsulfonate having an alkyl group having 12 to 26 carbon atoms as component (B), based on the total amount of the paper treating agent excluding water. and a paper treatment agent containing from 50 to 98% by mass of component (A) and from 0.7 to 7.9% by mass of a sulfosuccinate salt having an alkyl group having 12 to 26 carbon atoms as component (B), both in an amount of from 5 to 50% by mass, based on the total amount of the paper treatment agent.

[0045] (Paper) The paper of the present invention is treated with the paper treatment agent described above. Treating paper with the paper treatment agent of the present invention can impart a unique silk-like slippery texture and coreless softness to the paper, and further, the change in the moisture content of the paper between high-humidity and low-humidity environments is small, and moisture evaporation from the paper can be suppressed even in low-humidity environments. Examples of paper include tissue paper, toilet paper, facial tissue, pocket tissue, paper handkerchiefs, paper towels, etc. The basis weight of the paper is not particularly limited, but is preferably 1 to 50 g / m 2 is preferred, and 5 to 20 g / m 2 The number of plies (the number of layers of base paper) is not particularly limited, but is preferably 1 to 5, and more preferably 2 to 3.

[0046] The method for treating paper with a paper treatment agent is not particularly limited, and examples thereof include a method of applying the agent to the paper. The method for applying the agent to paper is not particularly limited, and examples thereof include transfer and spraying. Examples of these methods for applying the agent to paper include flexographic printing, gravure printing, spraying, and rotor dampening. In the flexographic printing method, a flexographic printing machine, which is a type of letterpress printing machine, is used to transfer the paper treatment agent to the paper with a roller equipped with a printing plate made of rubber or synthetic resin with an engraved surface. In the gravure printing method, a gravure printing machine, which is a type of intaglio printing machine, is used to transfer the paper treatment agent to the paper with a roller equipped with a metal cylinder with a plate-engraved surface. In the spray method, the paper treatment agent is sprayed in a mist form onto the paper from a nozzle using compressed air. In the rotor dampening method, the paper treatment agent is sprayed in a mist form onto the paper with a high-speed rotating disk.

[0047] The amount of paper treatment agent applied to paper is not particularly limited, but is preferably 1 to 7 g / m when converted into the mass of the paper treatment agent excluding water. 2 is preferred, and 1.5 to 6 g / m 2 is more preferred.

[0048] (Method for Improving the Texture of Paper) The method for improving the texture of paper of the present invention is characterized by treating the paper with the paper treatment agent described above. Specific aspects of treating the paper with the paper treatment agent are as described above. Treating the paper with the paper treatment agent of the present invention can impart a unique silky slippery feel and a flattened feel with little fluffiness, reducing the burden on the skin and evoking a feeling of gentleness to the skin, giving the paper a coreless softness and improving the texture.

[0049] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. (1) Preparation of paper treatment agent A paper treatment agent was prepared according to the following procedure. Each blended raw material was charged into a beaker in the amounts shown in Tables 1 to 5, and the mixture was stirred and mixed at a temperature at which each raw material dissolved, to prepare a paper treatment agent. The blended amount of each component shown in Tables 1 to 5 indicates the active component excluding water, if the apparent amount contains water. The apparent amount of water is included in the amount of water added in the tables.

[0050] (2) Preparation of Coated Paper The paper treatment agent obtained by the above method was applied to dry tissue (ply number 2, basis weight 12 to 14 g / m 2 The paper treatment agent was evenly applied to both sides of the base paper so that the mass of the paper treatment agent excluding water was 25% by mass ±3% of the mass of the base paper, and then the base paper was air-dried for 3 hours.

[0051] (3) Evaluation The paper treatment agents and coated papers prepared in each of the Examples and Comparative Examples above were evaluated as follows. [Characteristic silky slimy feel (sensory evaluation)] For the sensory evaluation, 10 experienced panelists rated the coated papers prepared by the procedure in (2) above using a score of 1 to 3 based on the following evaluation points, and the characteristic silky slimy feel was evaluated based on the average score using the following criteria. Evaluation points 3 points: A characteristic silky slimy feel is felt. 2 points: A slight characteristic silky slimy feel is felt. 1 point: No silky slimy feel is felt. Evaluation criteria ◎+: The average score of the 10 panelists was 2.5 points or more ◎: The average score of the 10 panelists was 2.0 points or more but less than 2.5 points ○: The average score of the 10 panelists was 1.5 points or more but less than 2.0 points ×: The average score of the 10 panelists was less than 1.5 points

[0052] [Coreless Softness (Sensory Evaluation)] For the sensory evaluation, the coated papers prepared by the procedure in (2) above were evaluated by 10 skilled panelists using a score of 1 to 3 based on the following evaluation criteria, and the coreless softness was evaluated based on the average score using the following criteria. Evaluation scores: 3 points: Coreless softness is felt. 2 points: Slight coreless softness is felt. 1 point: No coreless softness is felt. Evaluation criteria ◎+: The average score of the 10 panelists is 2.5 points or more ◎: The average score of the 10 panelists is 2.0 points or more but less than 2.5 points ○: The average score of the 10 panelists is 1.5 points or more but less than 2.0 points ×: The average score of the 10 panelists is less than 1.5 points

[0053] [Softness without a core (T0 / T m A KES-G5 handy compression tester (manufactured by Kato Tech Co., Ltd.) was used as the test equipment, and the T0 of two coated papers (one set) was measured. 2 The thickness (mm) at T mLoad: 50 gf / cm 2 The thickness (mm) at this time was measured.

[0054] This T0 value and T m The ratio of the values ​​T / T m The lower the value, the less difference there is in thickness when a load is applied and when no load is applied, indicating that the coated paper has become flat and has a less fluffy feel. m The value is correlated with the softness without a core in the sensory evaluation, and T0 / T m The lower the value, the softer the texture feels. Therefore, the softness of the texture is expressed as T0 / T m The value was evaluated according to the following criteria: Evaluation criteria: ⊚+: T0 / T m Value is less than 1.8 ◎: T0 / T m Value is 1.8 or more and less than 2.0. ○: T0 / T m Value is 2.0 or more and less than 2.2 ×: T0 / T m Value is 2.2 or more

[0055] [Humidity Environment Dependence] The coated paper prepared by the procedure in (2) above was left to stand for 24 hours in environments of 40% RH and 70% RH at 25°C, and the bone-dry mass of the paper was measured after leaving it to stand for 1.5 hours at 80°C, and the ratio of water to bone-dry mass of the paper at 40% RH and 70% RH at 25°C was calculated from these values. From these values, the difference in the ratio of water to bone-dry mass of the paper between 25°C, 40% RH and 25°C, 70% RH, was calculated, and the humidity environment dependency was evaluated according to the following criteria. Evaluation criteria ◎+: The difference in the proportion of water to the bone-dry mass of paper between 40% RH and 70% RH is less than 7.0% ◎: The difference in the proportion of water to the bone-dry mass of paper between 40% RH and 70% RH is 7.0% or more and less than 8.0% ◯: The difference in the proportion of water to the bone-dry mass of paper between 40% RH and 70% RH is 8.0% or more and less than 9.0% ×: The difference in the proportion of water to the bone-dry mass of paper between 40% RH and 70% RH is more than 9.0%

[0056] [Moisture content in low humidity environment] For the coated paper prepared by the procedure (2) above, the mass of the paper was measured after leaving it undisturbed in an environment of 25% RH and 25°C for 24 hours, and the bone-dry mass of the paper was measured after leaving it undisturbed at 80°C for 1.5 hours. The difference between the masses was used to calculate the ratio of water to the bone-dry mass of the paper at 25% RH and 25°C, which was taken as the moisture content at 25% RH. The moisture content in a low humidity environment was evaluated according to the following criteria: Evaluation criteria ◎+: Moisture content at 25% RH is 5.1% or more ◎: Moisture content at 25% RH is 4.7% or more and less than 5.1% ○: Moisture content at 25% RH is 4.5% or more and less than 4.7% ×: Moisture content at 25% RH is less than 4.5%

[0057] [Viscosity of Paper Treatment Agent] The viscosity of the paper treatment agent prepared by the procedure (1) above was measured at 60 rpm and 40°C using a Brookfield viscometer and evaluated according to the following criteria: Evaluation criteria: ⊚: Viscosity of the paper treatment agent is less than 500 mPa·s; ◯: Viscosity of the paper treatment agent is 500 mPa·s or more but less than 2000 mPa·s; ×: Viscosity of the paper treatment agent is 2000 mPa·s or more or cannot be measured (unable to maintain a uniform state).

[0058] [Stability of Paper Treatment Agent] The paper treatment agent prepared by the procedure (1) above was checked for its state immediately after preparation and after being left to stand at room temperature for one month, and evaluated based on the following criteria to ensure suitability for practical use. Evaluation criteria ◎: Maintains a uniform state one month after being prepared ○: Maintains a uniform state one month after being prepared, although there is some change in state ×: Not uniform from immediately after preparation, or cannot maintain a uniform state for one month

[0059] The formulations of the examples and comparative examples and the evaluation results for each item are shown in Tables 1 to 5. In Tables 1 to 5, the blending amount of each component is shown in parts by mass. In the evaluation of each item in Tables 1 to 5, the unique silky slippery feeling (sensory evaluation), coreless softness (sensory evaluation), coreless softness (T0 / T mIn the evaluations of humidity, environmental dependency, and moisture content in a low humidity environment, ○, ◎, and ◎+ indicate that the invention is good at solving the problem, in that order. In addition, if there is one or more × marks in all of these evaluations, it is determined that the problem of the invention is not solved. In the table, C in (B) sulfone salt indicates the number of carbon atoms in the alkyl group.

[0060]

[0061]

[0062]

[0063]

[0064]

[0065] As can be seen from Tables 1 to 5, Examples 1 to 35 used paper treatment agents containing (A) a polyhydric alcohol, (B) a sulfonate, and (C) water, with the content of (B) sulfonate being 0.05% by mass or more and less than 8.0% by mass relative to the total amount excluding water. These paper treatment agents had a unique silky, slippery feel and a coreless softness, were less dependent on the humidity environment, and suppressed moisture evaporation from paper even in low-humidity environments. The paper treatment agents had low viscosity and good stability over time. In addition, the T0 / T m The coated paper with a low value and a less fluffy feeling was found to have a good coreless softness in the sensory evaluation. m It was confirmed that the value correlates with the coreless softness in the sensory evaluation. Comparative Example 1 contained components (A) and (C) but not (B), Comparative Example 2 contained component (B) but in a large amount, Comparative Examples 3 and 4 contained components (B) and (C) but not (A), Comparative Examples 5 and 6 contained another anionic surfactant instead of component (B), and Comparative Examples 7 to 9 contained components (A) and (B) but not (C). None of these examples produced the same effects as the examples.

Claims

1. A paper treatment agent comprising (A) a polyhydric alcohol, (B) a sulfonate, and (C) water, wherein the content of (B) the sulfonate is 0.05% by mass or more and less than 8.0% by mass of the total amount excluding water.

2. The paper treating agent according to claim 1, wherein the sulfonate (B) has an alkyl group having 4 to 30 carbon atoms.

3. Paper treated with the paper treating agent according to claim 1 or 2.

4. A method for improving the texture of paper by treating the paper with the paper treating agent according to claim 1 or 2.