glue

Abstract

The present invention provides an adhesive that reduces viscosity increase even when stored in low-temperature environments such as winter, allows for easy application of the appropriate amount to the surface of plies, and enables strong bonding of plies together. [Solution] The adhesive of the present invention is characterized by containing modified starch, a water-soluble polymer other than starch, and methanol contained in an amount of 0 to 0.01 parts by mass per 100 parts by mass of the total amount of the modified starch and the water-soluble polymer other than starch.

Description

Technical Field

[0001] The present invention relates to an adhesive.

Background Art

[0002] In paper products such as kitchen paper and toilet paper, a plurality of thin base papers are laminated and integrated. An adhesive is used to laminate and integrate the base papers (plies) together.

[0003] Kitchen paper and toilet paper are formed in a long strip shape, and the long strip-shaped kitchen paper and toilet paper are wound around a paper tube to be commercialized. After applying an adhesive to the opposing surfaces of a pair of long strip-shaped plies, a pair of base papers are supplied between the opposing surfaces of a pair of pressing rolls, and the base papers are pressed against each other by the pressing rolls, so that the plies are laminated and integrated, and then continuously wound around a paper tube for manufacturing.

[0004] Patent Document 1 discloses an adhesive for roll-shaped paper containing (A) saccharides, (B) a viscosity modifier, and (C) glycol and / or triol, wherein (A) the saccharides contain glucose, and (B) the viscosity modifier contains an aqueous polymer having a weight average molecular weight of 20,000 to 4,000,000.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] In the manufacturing of kitchen paper and toilet paper, in order to maintain the texture and absorbency of the ply, the adhesive is not applied to the entire surface of the ply, but rather in a dotted manner. Therefore, it is necessary to apply the adhesive to the surface of the ply in the appropriate amount.

[0007] However, the above-mentioned adhesive for rolled paper has a problem in that when stored in low-temperature environments such as winter, its viscosity increases and sedimentation occurs, making it difficult to apply the appropriate amount of adhesive to the surface of the ply.

[0008] When the viscosity of the adhesive increases, it becomes difficult to supply the appropriate amount of adhesive, resulting in a larger amount of adhesive being applied to the surface of the ply. This impairs the texture of the resulting kitchen paper or toilet paper, or, due to the water absorption of the ply, the adhesive applied to the ply penetrates to the opposite side of the ply, contaminating the press roll during manufacturing.

[0009] The present invention provides an adhesive that reduces viscosity increase even when stored in low-temperature environments such as winter, allows for easy application of the appropriate amount to the surface of plies, and enables strong bonding of plies together. [Means for solving the problem]

[0010] The adhesive of the present invention is characterized by containing modified starch, a water-soluble polymer other than starch, and methanol contained in an amount of 0 to 0.01 parts by mass per 100 parts by mass of the total amount of the water-soluble polymer other than starch and the modified starch. [Effects of the Invention]

[0011] The adhesive of the present invention exhibits minimal viscosity increase even in low-temperature environments such as winter, and has excellent low-temperature storage stability. By reducing viscosity changes, it can be easily applied in the appropriate amount to the surface of the ply, and can firmly integrate the ply pieces together without impairing the texture or water absorption of the ply. [Modes for carrying out the invention]

[0012] In the numerical ranges described stepwise in this specification, the upper or lower limit of one step in the numerical range can be arbitrarily combined with the upper or lower limit of another step in the numerical range. In the numerical ranges described in this specification, the upper or lower limit of that numerical range may be replaced with values ​​shown in the examples or values ​​that can be uniquely derived from the examples. In this specification, numbers connected by "~" mean a numerical range that includes the numbers before and after "~" as the lower and upper limits.

[0013] The adhesive of the present invention comprises modified starch, a water-soluble polymer other than starch, and methanol contained in an amount of 0 to 0.01 parts by mass per 100 parts by mass of the total amount of the water-soluble polymer other than starch and the modified starch.

[0014] The adhesive of the present invention uses a combination of modified starch and a water-soluble polymer other than starch, and limits the methanol content to a predetermined amount or less, thereby providing excellent storage stability in a low-temperature atmosphere, reducing viscosity increase, and enabling good adhesion and integration of plies.

[0015] [Processed starch] The adhesive contains modified starch. Modified starch is obtained by processing unprocessed starch, such as natural starch, with physical, chemical, or enzymatic treatment, either individually or in combination. The unprocessed starch used as the raw material for modified starch is not particularly limited and includes, for example, potato starch, tapioca starch, corn starch, glutinous rice starch, sago starch, sweet potato starch, mung bean starch, and wheat starch. Potato starch and tapioca starch are preferred, and potato starch is more preferred. Modified starch may be used alone or in combination of two or more types.

[0016] Modified starch is usually composed of two types of polysaccharides: amylose and amylopectin. The amylose content in modified starch is preferably 10% by mass or more, more preferably 13% by mass or more, more preferably 15% by mass or more, and more preferably 20% by mass or more. The amylose content in modified starch is preferably 30% by mass or less, more preferably 28% by mass or less, and more preferably 26% by mass or less. When the amylose content in modified starch is within the above range, the adhesive has excellent low-temperature storage properties and adhesive properties. Note that the amylose content in modified starch refers to the total amount of amylose and amylose that has undergone processing.

[0017] The amylopectin content in modified starch is preferably 70% by mass or more, more preferably 72% by mass or more, and more preferably 74% by mass or more. The amylopectin content in modified starch is preferably 90% by mass or less, more preferably 87% by mass or less, more preferably 85% by mass or less, and more preferably 80% by mass or less. When the amylopectin content in modified starch is within the above range, the adhesive has excellent low-temperature storage properties and adhesive properties. Note that the amylopectin content in modified starch refers to the total amount of amylopectin and amylopectin that has undergone processing.

[0018] The average particle size of the modified starch is preferably 5 μm or more, more preferably 10 μm or more, more preferably 12 μm or more, more preferably 13 μm or more, more preferably 15 μm or more, more preferably 30 μm or more, more preferably 40 μm or more, more preferably 50 μm or more, more preferably 60 μm or more, more preferably 70 μm or more, more preferably 80 μm or more, more preferably 90 μm or more, and more preferably 100 μm or more. The average particle size of the modified starch is preferably 160 μm or less, more preferably 150 μm or less. It is preferably 80 μm or less, more preferably 70 μm or less, and still more preferably 60 μm or less. When the average particle diameter of the modified starch is within the above range, it is possible to optimize the gelatinization temperature of the modified starch and, due to the presence of the water-soluble polymer, reduce recrystallization under a low-temperature atmosphere and reduce the loss of water retained in the modified starch. This can reduce the degree of increase in the viscosity of the adhesive when stored under a low-temperature atmosphere and impart excellent adhesiveness to the adhesive. The average particle diameter of the modified starch refers to the particle diameter (50% cumulative particle diameter) at which the cumulative frequency (cumulative from particles with a smaller particle diameter) in the volume-based particle size distribution by the laser scattering method is 50%.

[0019] The modified starch is not particularly limited. Examples include etherified starch, esterified starch, crosslinked starch, etherified crosslinked starch, esterified crosslinked starch, oxidized starch, esterified oxidized starch, acid-treated starch, amidated starch, cationized starch, baked dextrin, maltodextrin, amphoteric starch, and those obtained by gelatinizing these modified starches. Esterified starch, esterified oxidized starch, etherified starch, baked dextrin, and maltodextrin are preferred, and esterified oxidized starch, oxidized starch, cationized starch, hydroxyalkyl etherified starch, carboxyalkyl etherified starch, baked dextrin, and maltodextrin are more preferred.

[0020] Examples of the oxidized starch include those obtained by treating unprocessed starch with an oxidizing agent. Examples of the oxidizing agent include halogens such as chlorine, bromine, hypochlorite, and hypobromite. Examples of the salt include alkali metal salts such as potassium and sodium.

[0021] Etherified starch refers to a product obtained by etherifying a part of the hydroxyl groups of raw starch. Examples of etherified starch include alkyl etherified starch such as methyl etherified starch, ethyl etherified starch, and propyl etherified starch; hydroxyalkyl etherified starch such as hydroxymethyl etherified starch, hydroxyethyl etherified starch, hydroxypropyl etherified starch, and hydroxybutyl etherified starch; carboxyalkyl etherified starch such as carboxymethyl etherified starch and carboxyethyl etherified starch; allyl etherified starch, etc. Among them, hydroxyalkyl etherified starch and carboxyalkyl etherified starch are preferred.

[0022] Esterified starch refers to a product obtained by esterifying a part of the hydroxyl groups of raw starch. Examples of esterified starch include inorganic acid esterified starch such as nitrate esterified starch, sulfate esterified starch, phosphate esterified starch, and urea phosphate esterified starch; organic acid esterified starch such as acetoacetic acid esterified starch, acetic acid esterified starch, xanthogen acetic acid esterified starch, succinic acid esterified starch, maleic anhydride esterified starch, and fumaric anhydride esterified starch.

[0023] Crosslinked starch refers to a product obtained by reacting a compound having a polyfunctional group with raw starch to form a crosslinked structure intramolecularly or intermolecularly through the hydroxyl groups of the raw starch. Examples of crosslinked starch include phosphate crosslinked starch, acetylated phosphate crosslinked starch, adipic acid crosslinked starch, acetylated adipic acid crosslinked starch, formaldehyde crosslinked starch, acrolein crosslinked starch, epichlorohydrin crosslinked starch, etc.

[0024] Examples of amidated starch include carbamoylethylated starch, etc.

[0025] Cationic starch is obtained by treating unprocessed starch with a compound having a cationic group. Examples of compounds having a cationic group include ammonium halides such as 2-diethylaminoethyl chloride and 2,3-epoxypropyltrimethylammonium chloride.

[0026] Calcined dextrin is a modified starch obtained by heat-treating unprocessed starch. Calcined dextrin can be produced, for example, by heat-treating unprocessed starch containing water to a temperature of preferably 120 to 200°C. During the heat treatment, a portion of the unprocessed starch partially decomposes and undergoes differential bonding, transforming into short-chain dextrin.

[0027] Maltodextrin can be produced by partially hydrolyzing unprocessed starch using enzymes or acids. It is a mixture of molecules in which several to about 20 glucose units are linked together in a linear chain, and is a type of dextrin.

[0028] Amphoteric starch refers to starch obtained by treating unprocessed starch with a compound having a cationic group and / or a compound having anionic groups, or a compound having both cationic and anionic groups, and means starch that has both cationic and anionic groups.

[0029] The modified starch preferably contains carboxyalkyl etherified starch and calcined dextrin or maltodextrin.

[0030] The content of carboxyalkyl etherified starch in the modified starch is preferably 5% by mass or more, more preferably 10% by mass or more, and more preferably 15% by mass or more. The content of carboxyalkyl etherified starch in the modified starch is preferably 50% by mass or less, more preferably 45% by mass or less, more preferably 40% by mass or less, and more preferably 35% by mass or less. When the content of carboxyalkyl etherified starch is within the above range, the degree of viscosity increase of the adhesive when stored in a low-temperature atmosphere is reduced, and the adhesive has excellent adhesion.

[0031] The calcined dextrin content in the modified starch is preferably 50% by mass or more, more preferably 55% by mass or more, more preferably 60% by mass or more, and more preferably 65% ​​by mass or more. The calcined dextrin content in the modified starch is preferably 95% by mass or less, more preferably 90% by mass or less, and more preferably 85% by mass or less. When the calcined dextrin content is within the above range, the adhesive exhibits reduced viscosity increase when stored in a low-temperature atmosphere and also has excellent adhesive properties.

[0032] The maltodextrin content in the modified starch is preferably 50% by mass or more, more preferably 55% by mass or more, more preferably 60% by mass or more, and more preferably 65% ​​by mass or more. The maltodextrin content in the modified starch is preferably 95% by mass or less, more preferably 90% by mass or less, and more preferably 85% by mass or less. When the maltodextrin content is within the above range, the adhesive exhibits reduced viscosity increase when stored in a low-temperature atmosphere and also has excellent adhesive properties.

[0033] Although the detailed mechanism has not been elucidated, the adhesive uses a combination of modified starch, which is obtained by treating some of the hydroxyl groups of unprocessed starch as described above, and a water-soluble polymer other than starch (unprocessed starch). In addition to the processing, the presence of the water-soluble polymer reduces recrystallization of the modified starch in a low-temperature atmosphere and reduces the loss of water retained within the modified starch, thereby reducing the degree of viscosity increase of the adhesive when stored in a low-temperature atmosphere.

[0034] Furthermore, we discovered that methanol acts on the recrystallization of modified starch, and by limiting the methanol content to a predetermined amount or less relative to the total amount of modified starch and water-soluble polymer, we reduced the recrystallization of modified starch under low-temperature conditions and reduced the loss of moisture retained within the modified starch, thereby reducing the degree of viscosity increase of the adhesive when stored under low-temperature conditions.

[0035] [Water-soluble polymers other than starch] The adhesive contains water-soluble polymers other than starch. Note that the term "starch" encompasses both unprocessed and processed starch. In this invention, a water-soluble polymer refers to a polymer that dissolves in 100g of water at 25°C in amounts of 1g or more.

[0036] The water-soluble polymer is not particularly limited, and examples include water-soluble celluloses, polyvinyl alcohol, polyvinylpyrrolidone, carboxyvinyl polymers, and polyethylene glycol. Water-soluble celluloses and polyvinyl alcohol are preferred because they have excellent low-temperature storage properties and adhesive properties, and cellulose ether derivatives or salts thereof are more preferred.

[0037] The term "water-soluble celluloses" is a concept that includes not only salts of cellulose, but also derivatives or salts thereof in which all or part of the hydroxyl groups of cellulose form ether bonds (hereinafter referred to as "cellulose ether derivatives or salts thereof"). The salts are not particularly limited, and examples include alkali metal salts such as sodium salts and potassium salts; alkaline earth metal salts such as calcium salts and magnesium salts; and ammonium salts, with alkali metal salts and ammonium salts being preferred.

[0038] Cellulose ether derivatives or salts thereof are not particularly limited and include, for example, alkylcellulose such as methylcellulose and ethylcellulose or salts thereof; hydroxyalkylcellulose such as hydroxyethylcellulose and hydroxypropylcellulose or salts thereof; alkyl(hydroxyalkyl)cellulose such as hydroxyethylmethylcellulose, hydroxypropylmethylcellulose, and hypromellose or salts thereof; alkyl(hydroxyalkyl)cellulose derivatives such as hypromellose acetate succinate and hypromellose phthalate or salts thereof; carboxyalkylcellulose such as carboxymethylcellulose (carmellose), carmellose potassium, carmellose calcium, and carmellose sodium or salts thereof; and carboxyalkylcellulose derivatives such as croscarmellose sodium or salts thereof.

[0039] The alkyl group in the above-mentioned cellulose ether derivative is not particularly limited, but linear or branched alkyl groups having 1 to 6 carbon atoms are preferred. Furthermore, the etherification rate (substitution rate of substituents that form ether bonds, such as alkyl groups, hydroxyalkyl groups, and carboxyalkyl groups: %) in the cellulose ether derivative is not particularly limited, but 10 to 90% is preferred, and 20 to 80% is more preferred, as it provides excellent low-temperature storage for the adhesive. The etherification rate (%) is a value measured for the cellulose ether derivative by the method described in the 16th edition of the Japanese Pharmacopoeia or a method similar thereto.

[0040] As for water-soluble celluloses, cellulose ether derivatives or salts thereof are preferred due to their excellent low-temperature storage properties for adhesives, at least one water-soluble cellulose selected from the group consisting of alkylcellulose, hydroxyalkylcellulose, alkyl(hydroxyalkyl)cellulose, and carboxyalkylcellulose and their salts is more preferred, at least one water-soluble cellulose selected from the group consisting of alkylcellulose having an alkyl group with 1 to 6 carbon atoms, hydroxyalkylcellulose having an alkyl group with 1 to 6 carbon atoms, and carboxyalkylcellulose having an alkyl group with 1 to 6 carbon atoms and their salts is more preferred, and at least one water-soluble cellulose selected from the group consisting of methylcellulose, ethylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, hypromellose, and carboxymethylcellulose and their salts is even more preferred.

[0041] Water-soluble celluloses preferably contain cellulose ether derivatives or salts thereof, more preferably contain cellulose ether derivatives and salts thereof, preferably contain salts of carboxyalkyl cellulose and alkyl(hydroxyalkyl) cellulose, and preferably contain ammonium salts of carboxyalkyl cellulose and alkyl(hydroxyalkyl) cellulose.

[0042] The content of water-soluble celluloses in the water-soluble polymer is preferably 50% by mass or more, more preferably 60% by mass or more, more preferably 70% by mass or more, more preferably 80% by mass or more, more preferably 90% by mass or more, more preferably 95% by mass or more, and more preferably 99% by mass or more.

[0043] In the adhesive, the content of water-soluble polymers other than starch is preferably 2 parts by mass or more, more preferably 3 parts by mass or more, more preferably 4 parts by mass or more, and more preferably 5 parts by mass or more, per 100 parts by mass of modified starch. In the adhesive, the content of water-soluble polymers other than starch is preferably 350 parts by mass or less, more preferably 300 parts by mass or less, more preferably 250 parts by mass or less, and more preferably 220 parts by mass or less, per 100 parts by mass of modified starch. When the content of water-soluble polymers is 2 parts by mass or more, although the mechanism is not clear, the recrystallization of modified starch under low temperature conditions is reduced, and the amount of water retained in the modified starch is reduced, thereby reducing the degree of viscosity increase of the adhesive when stored under low temperature conditions. When the content of water-soluble polymers is 350 parts by mass or less, the viscosity of the adhesive can be optimized. For example, when bonding highly absorbent paper products such as kitchen paper or toilet paper together, the adhesive can be applied in the appropriate amount to the paper product, and the adhesive can be prevented from seeping to the side opposite to the coated surface.

[0044] The adhesive preferably contains 100 parts by mass of modified starch containing 5 to 50% by mass of etherified starch (preferably 10 to 40% by mass, more preferably 15 to 35% by mass) and 50 to 95% by mass of at least one dextrin selected from the group consisting of calcined dextrin and maltodextrin (preferably 60 to 90% by mass, more preferably 65 to 85% by mass, more preferably 70 to 85% by mass), and 3 to 40 parts by mass of water-soluble polymer containing 50% or more by mass of alkyl (hydroxyalkyl) cellulose (preferably 60% or more by mass, more preferably 70% or more by mass, more preferably 80% or more by mass, more preferably 90% or more by mass). The adhesive has been designed to reduce the degree of viscosity increase when stored in a low-temperature atmosphere.

[0045] [water] The adhesive preferably contains water. The water content of the adhesive may be adjusted as appropriate depending on the content of starch and water-soluble polymer and their viscosity. The water content in the adhesive is preferably 500 parts by mass or more, more preferably 600 parts by mass or more, more preferably 700 parts by mass or more, more preferably 800 parts by mass or more, more preferably 900 parts by mass or more, and more preferably 1000 parts by mass or more, per 100 parts by mass of modified starch. The water content in the adhesive is preferably 30,000 parts by mass or less, more preferably 25,000 parts by mass or less, more preferably 23,000 parts by mass or less, more preferably 22,000 parts by mass or less, more preferably 21,000 parts by mass or less, and more preferably 20,000 parts by mass, per 100 parts by mass of modified starch.

[0046] [methanol] The adhesive contains 0 to 0.01 parts by mass of methanol per 100 parts by mass of the total amount of modified starch and water-soluble polymers other than starch. Note that 0 parts by mass of methanol means the adhesive does not contain methanol.

[0047] The methanol content is kept below a predetermined level to suppress the recrystallization of modified starch contained in the adhesive. By reducing the recrystallization of modified starch in the adhesive under low-temperature conditions and reducing the loss of moisture retained within the modified starch, the degree of viscosity increase of the adhesive when stored under low-temperature conditions is reduced while maintaining the adhesive's excellent adhesive properties.

[0048] The methanol content in the adhesive is 0 to 0.01 parts by mass per 100 parts by mass of the total amount of modified starch and water-soluble polymers other than starch, preferably 0 to 0.005 parts by mass, more preferably 0 to 0.003 parts by mass, even more preferably 0 to 0.001 parts by mass, and even more preferably 0 parts by mass.

[0049] [glue] The adhesive can be manufactured by mixing modified starch, a water-soluble polymer other than starch, and water and other additives as needed, and heating the mixture to 50-90°C as needed to ensure uniform mixing. The additives can be any additives that do not impair the physical properties of the adhesive, such as defoamers and preservatives.

[0050] The initial viscosity of the adhesive at 30°C is preferably 10 mPa·s or more, more preferably 15 mPa·s or more, more preferably 20 mPa·s or more, and more preferably 25 mPa·s or more. The initial viscosity of the adhesive at 30°C is preferably 220 mPa·s or less, more preferably 215 mPa·s or less, more preferably 210 mPa·s or less, more preferably 205 mPa·s or less, and more preferably 200 mPa·s or less. When the initial viscosity of the adhesive at 30°C is 10 mPa·s or more, when bonding highly absorbent paper products such as kitchen paper and toilet paper together, penetration into the paper products is reduced, and the adhesive is more likely to remain on the surface of the paper products, thereby strengthening the bond between the paper products. When the initial viscosity of the adhesive at 30°C is 220 mPa·s or less, when bonding highly absorbent paper products such as kitchen paper and toilet paper together, the adhesive can be applied in an appropriate amount to the paper products, and the adhesive can be prevented from seeping to the side opposite to the coated surface.

[0051] The initial viscosity of the adhesive at 10°C is preferably 15 mPa·s or higher, more preferably 25 mPa·s or higher, and even more preferably 30 mPa·s or higher. The initial viscosity of the adhesive at 10°C is preferably 500 mPa·s or lower, more preferably 450 mPa·s or lower, even more preferably 400 mPa·s or lower, and even more preferably 300 mPa·s or lower.

[0052] The viscosity of the adhesive after low-temperature storage is preferably 20 mPa·s or higher, more preferably 30 mPa·s or higher, more preferably 40 mPa·s or higher, and more preferably 50 mPa·s or higher. The viscosity of the adhesive after low-temperature storage is preferably 500 mPa·s or less, more preferably 450 mPa·s or less, more preferably 420 mPa·s or less, and more preferably 400 mPa·s or less. Note that the viscosity of the adhesive after low-temperature storage refers to the viscosity of the adhesive after it has been left for 144 hours while maintaining its liquid temperature at 5°C, and then the liquid temperature of the adhesive is returned to 10°C.

[0053] The viscosity of the adhesive at the measurement temperature is measured using a BH-type viscometer, according to the measurement method compliant with JIS K7117-1. This is done by selecting a spindle (1-7) according to the sample viscosity, maintaining the adhesive temperature at the measurement temperature, and measuring the viscosity at a rotation speed of 20 rpm.

[0054] The above adhesive can be suitably used in the manufacture of paper products, particularly highly absorbent paper products such as kitchen paper and toilet paper. It can be suitably used in the manufacture of long-length paper products.

[0055] Kitchen paper and toilet paper are often made by laminating multiple thin sheets of base paper (ply). When bonding the plies together, adhesive is applied to the surface of each ply. However, because plies are highly absorbent, it is necessary to apply a predetermined amount of adhesive to the surface of each ply to ensure that an appropriate amount of adhesive is present on the surface of each ply.

[0056] If the viscosity of the adhesive is high, it becomes difficult to apply the adhesive to the ply surface, and the amount of adhesive applied tends to increase. When the amount of adhesive is too high, the ply absorbs the excess adhesive, and the applied adhesive seeps through to the opposite side of the coated surface. This results in a deterioration of the appearance of the resulting paper product, and also causes the surface of the pressure rolls used in the ply lamination process to become contaminated with adhesive, as will be described later.

[0057] Conventional adhesives increase in viscosity when stored in low-temperature environments such as winter. However, as described above, by using modified starch and water-soluble polymers in combination and keeping the methanol content below a predetermined amount, the viscosity increase is minimal even after storage in low-temperature environments. This allows for the application of an appropriate amount of adhesive to the ply surface, preventing the adhesive from seeping to the opposite side of the adhesive-coated surface. This ensures that an appropriate amount of adhesive is present on the ply surface, firmly laminating and integrating the ply pieces together, enabling the stable production of paper products.

[0058] The basis weight of the plies, which are the constituent components of kitchen paper, is 10-80 g / m². 2 Preferably, 20-60 g / m 2 This is preferable. Note that the basis weight of the kitchen paper refers to the value measured in accordance with the provisions of JIS P8124 (1998). Note that the basis weight of the ply is the value obtained by dividing the basis weight of the kitchen paper by the number of ply sheets.

[0059] The basis weight of the plies, which are the constituent components of toilet paper, is 10-30 g / m². 2 Preferably, 18-25 g / m 2 This is preferable. The basis weight of the toilet paper can be calculated by measuring the basis weight of the toilet paper in accordance with the provisions of JIS P8124 and dividing this basis weight by the number of plies.

[0060] As mentioned above, kitchen paper and toilet paper are composed of base paper (ply). Ply is obtained by papermaking a slurry containing pulp components, which are the raw material for fibers.

[0061] Pulp components include wood pulp, non-wood pulp, and recycled paper pulp. Examples of wood pulp produced from wood include hardwood pulp (hardwood kraft pulp (LKP)), softwood pulp (softwood kraft pulp (NKP)), sulfite pulp (SP), dissolved pulp (DP), soda pulp (AP), unbleached kraft pulp (UKP), and oxygen-bleached kraft pulp (OKP), among other chemical pulps. Semi-chemical pulps such as semi-chemical pulp (SCP) and chemigroundwood pulp (CGP), as well as mechanical pulps such as crushed wood pulp (GP) and thermomechanical pulp (TMP, BCTMP), may also be used.

[0062] Non-wood pulps produced from plants and animals other than wood include cotton pulps such as cotton linters and cotton lint, non-wood pulps such as hemp, straw, and bagasse, and cellulose, chitin, and chitosan isolated from sea squirts and seaweed.

[0063] Recycled paper pulp is pulp manufactured using recycled paper, that is, pulp produced from papermaking processes. Examples of recycled paper pulp include so-called milk carton pulp, which is made from paper cartons used for packaging liquids such as milk cartons, and deinked pulp, which is made from newspapers and magazines.

[0064] The ply may contain additives such as drying agents, wetting agents, softeners, bulking agents, dyes, fragrances, dispersants, water filtration improvers, pitch control agents, yield improvers, and sizing agents.

[0065] Next, we will explain the procedure for manufacturing long rolls of kitchen paper using adhesive. The procedure for manufacturing long rolls of toilet paper is the same as described below.

[0066] A pair of elongated plies are prepared, and by causing each ply to bulge from one side to the other, convex embossed patterns, such as cylindrical or prismatic shapes, are formed in a scattered manner.

[0067] The adhesive is applied to the top of each emboss (the protruding top) on one of the pair of plies. Since the viscosity increase of the adhesive is reduced even after low-temperature storage, it can be applied accurately and in the appropriate amount to the limited area of ​​the top of the emboss on the ply. Because the viscosity of the adhesive is also optimized, it will not seep to the side of the ply opposite to the surface on which the adhesive is applied.

[0068] Subsequently, a pair of plies are stacked so that their other faces face each other to produce a laminated ply. At this time, the tops of the embossing on each ply (the protruding tops) are aligned with each other.

[0069] By supplying the above-mentioned laminated ply between the opposing surfaces of a pair of pressing rolls, pressing the laminated ply from both sides with the pair of pressing rolls, and bonding and integrating the tops of the embossed surfaces of the pair of ply with adhesive applied to the tops of the embossed surfaces of the ply (TIP to TIP embossed laminated structure), the ply can be laminated and integrated to produce a long roll of kitchen paper.

[0070] The resulting kitchen paper is firmly bonded and integrated at the top of the ply's embossing. Furthermore, no adhesive seeps out onto one side of the ply that makes up the outer surface of the kitchen paper (the side where the indented area caused by the embossing is formed), and the resulting kitchen paper has an excellent appearance. Because the kitchen paper is bonded and integrated with an appropriate amount of adhesive, it retains the texture of the ply and has a soft texture without becoming stiff due to the adhesive.

[0071] The resulting long roll of kitchen paper is then glued and integrated at its leading end to a paper tube, and then continuously wound onto the paper tube in a roll. When the entire length of the long roll of kitchen paper is wound onto the paper tube, the final end of the kitchen paper is detachably glued and integrated to the outer surface of the kitchen paper that was wound onto the paper tube prior to this final end, thus forming a roll product.

[0072] The above adhesive can also be used to bond the leading edge of the kitchen paper to the paper tube, or to bond the final end of the kitchen paper to the outer surface of the kitchen paper that has been wound onto the paper tube in advance.

[0073] The above manufacturing method describes a case where embossing is formed in a dotted pattern on the ply and the tops of the embossing are bonded together with an adhesive (tip-to-tip embossed laminated structure), but it is not limited to this.

[0074] In the same manner as described above, embossing can be formed on the ply in a dotted pattern. Adhesive can be applied to the top of the embossing on one ply (the protruding top), and the convex embossing on one ply can be fitted into the embossing on the other ply from the recessed (concave) side. A pair of ply can then be stacked to produce a laminated ply (nested embossed laminated structure). This laminated ply can then be supplied between the opposing surfaces of a pair of pressing rolls in the manner described above. The embossing on one ply can be fitted into the embossing on the other ply using the adhesive applied to the top of the embossing, thereby bonding and integrating the embossing on the pair of ply to produce a long roll of kitchen paper. Adhesive can also be applied to the inner bottom surface of the concave side of the embossing on the other ply.

[0075] Furthermore, although the above manufacturing method describes the case in which an emboss is formed on the ply, a laminated ply may also be manufactured by applying adhesive in a dotted pattern to one side of one ply without forming an emboss on the ply, and then overlapping the other ply onto the adhesive-coated surface of one ply. [Examples]

[0076] The present invention will be described more specifically below with reference to examples, but the present invention is not limited thereto. Specific numerical values ​​such as blending ratios (content), physical properties, and parameters used in the following description may be replaced with the corresponding upper limits (numerical values ​​defined as "less than or equal to" or "less than") or lower limits (numerical values ​​defined as "greater than or equal to") of the blending ratios (content), physical properties, and parameters described in the "Means for Solving the Problems" section.

[0077] The following compounds were used in the examples and comparative examples.

[0078] [Processed starch] • Esterified oxidized starch (raw material: unprocessed starch, potato starch; amylose: 25% by mass; amylopectin: 75% by mass; average particle size: 42.5 μm; manufactured by Matsutani Chemical Co., Ltd.; product name: "PERFECTAMYL A5914") • Hydroxypropyl etherified starch (raw material: unprocessed starch: tapioca starch, amylose: 17% by mass, amylopectin: 83% by mass, average particle size: 17 μm, manufactured by Matsutani Chemical Co., Ltd., product name "Marigold") • Oxidized starch (raw material: unprocessed starch, corn starch; amylose: 25% by mass; amylopectin: 75% by mass; average particle size: 13-15 μm; manufactured by Nippon Corn Starch Co., Ltd.; product name "SK-20") • Cationized starch (raw material: unprocessed starch, potato starch; amylose: 25% by mass; amylopectin: 75% by mass; average particle size: 30-40 μm; manufactured by Oji Corn Starch Co., Ltd.; product name "K-500") • Carboxymethyl etherified starch (raw material: unprocessed starch, potato starch; amylose: 25% by mass; amylopectin: 75% by mass; average particle size: 141 μm; manufactured by Matsutani Chemical Co., Ltd.; product name: "SOLVITOSE FC50") • Calcined dextrin (raw material: unprocessed starch: potato starch, amylose: 25% by mass, amylopectin: 75% by mass, average particle size: 128 μm, manufactured by Matsutani Chemical Co., Ltd., product name "AVEDEX 36LAC14") • Maltodextrin (raw materials: unprocessed starch, tapioca starch and corn starch; average particle size: 46 μm; manufactured by Matsutani Chemical Co., Ltd.; product name "TK-16")

[0079] [Raw starch] • Unprocessed starch (raw material: corn starch, amylose: 25% by mass, amylopectin: 75% by mass, average particle size: 12.5 μm, manufactured by Oji Corn Starch Co., Ltd., product name "Corn Starch IP")

[0080] [Water-soluble polymers other than starch] • Carboxymethylcellulose ammonium (manufactured by Nichirin Co., Ltd., product name "NA-3L", solubility in 100g of water at 25°C: 1g or more) • Carboxymethylcellulose sodium 1 (manufactured by Daicel Finechem, product name "CMC-1240", solubility in 100g of water at 25°C: 1g or more) • Carboxymethylcellulose sodium 2 (manufactured by Daicel Finechem, product name "CMC-1220", solubility in 100g of water at 25°C: 1g or more) • Hydroxypropyl methylcellulose (manufactured by Shin-Etsu Chemical Co., Ltd., product name "Metolose 60SH-15", solubility in 100g of water at 25°C: 1g or more)

[0081] [methanol] • Methanol (anhydrous)

[0082] [Additives] • Silicone-based antifoaming agent (manufactured by Dow-Toray, product name "FS Antifoam 92") • Isothiazolone-based preservative (manufactured by Kei-I Kasei Co., Ltd., product name "KB1030")

[0083] (Examples 1-10, Comparative Examples 1-6) A mixture was prepared by mixing the specified amounts of modified starch, unprocessed starch, water-soluble polymers other than starch, water, methanol, and additives shown in Tables 1 and 2. This mixture was heated to 55°C and then uniformly mixed to obtain an adhesive. In Tables 1 and 2, "water-soluble polymers other than starch" is simply referred to as "water-soluble polymers."

[0084] The initial viscosity at 30°C, the initial viscosity at 10°C, and the viscosity after low-temperature storage of the obtained adhesive were measured in the manner described above, and the results are shown in Tables 1 and 2. "Viscosity after low-temperature storage" refers to the viscosity of the adhesive after it has been left for 144 hours while maintaining its liquid temperature at 5°C, and then the liquid temperature of the adhesive has been raised to 10°C.

[0085] In Tables 1 and 2, "Initial viscosity at 30°C" is listed in the "Initial viscosity at 30°C (mPa·s)" column. "Initial viscosity at 10°C" is listed in the "Initial viscosity at 10°C (mPa·s)" column under "Low-temperature storage properties." "Viscosity after low-temperature storage" is listed in the "Viscosity after low-temperature storage (mPa·s)" column under "Low-temperature storage properties."

[0086] The adhesive properties of the obtained adhesives were measured according to the following procedure, and the results are shown in Tables 1 and 2.

[0087] (Adhesiveness) A kitchen towel (manufactured by Oji Nepia Co., Ltd., product name "Super Absorbent Kitchen Towel") was cut into a flat rectangular shape measuring 140 mm in width and 180 mm in length. The two plies that make up the cut kitchen towel (basis weight: 43 g / m²) were then cut. 2 ) was peeled off and separated.

[0088] A glass plate was prepared, 2g of adhesive was dropped onto one side of the glass plate, and a thin film was formed using a bar coater #50. The thin film of adhesive formed on the glass plate was then brushed with a silicone brush (bristle length 9mm, width 55mm x length 110mm, density: 5 bristles / 1m). 2 It was transcribed to ).

[0089] Place the brush on the surface of one of the two plies mentioned above (the outer surface that was not glued together in the kitchen towel) for 2 seconds, and apply 7g / m². 2 The adhesive was transferred in a dotted pattern. The adhesive was transferred in a dotted pattern at regular intervals in both the width and length directions over a rectangular area measuring 55 mm in width and 110 mm in length.

[0090] A laminated ply was created by attaching the other ply to the adhesive-coated surface of one ply, which had the above adhesive transferred to it, with their surfaces (the outer surfaces that were not bonded together in the kitchen towel) facing each other.

[0091] The laminated plywood was placed on a hot plate maintained at 60°C, and a 2kg load was placed on it for 10 seconds to allow the adhesive to dry. After removing the laminated plywood from the hot plate, a glass plate was placed on top of it, and a 2kg load was applied to the glass plate. Next, the laminated plywood was cured in a 25°C atmosphere for 30 minutes, then the load on the laminated plywood was removed, and the laminated plywood was cured at 25°C for 12 hours to obtain the test specimen.

[0092] The test specimen was suspended vertically with its 140mm shorter end facing upwards, and the upper end of one of the plies was supported. In this state, the rectangular transfer area of ​​the adhesive bonding the pair of plies together was oriented horizontally in the 55mm width direction and vertically in the 110mm length direction.

[0093] The upper end of the other ply of the test specimen was bent 180° vertically downwards, and a weight was attached to this downwardly bent portion. Starting with a 1g weight, it was left for 10 seconds. If the other ply did not completely detach from the first ply, an additional 1g weight was added and left for another 10 seconds. The above process was repeated until the other ply completely detached from the first ply. The maximum weight that could be held for 10 seconds without completely detaching from the first ply was defined as the load-bearing capacity (g).

[0094] Table 1

[0095] Table 2

Claims

1. An adhesive characterized by comprising modified starch, a water-soluble polymer other than starch, and methanol contained in an amount of 0 to 0.01 parts by mass per 100 parts by mass of the total amount of the water-soluble polymer other than starch and the modified starch.

2. The adhesive according to claim 1, characterized in that it contains 5 to 350 parts by mass of a water-soluble polymer other than the starch, per 100 parts by mass of the above-mentioned modified starch.

3. The adhesive according to claim 1 or 2, characterized in that it contains 500 to 30,000 parts by mass of water per 100 parts by mass of the above-mentioned modified starch.

4. The adhesive according to claim 1 or 2, characterized in that its viscosity at 30°C is 10 to 200 mPa·s.

5. An adhesive according to claim 1 or claim 2, used for bonding and integrating plies of kitchen paper or toilet paper together.

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