JP3326325B2 - Swellable laminated sheet - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet for adhering to the inner surface of a tray for transporting cooked rice for business use or as an inner bag into which cooked rice is absorbed to absorb dew condensation water, and to maintain the freshness of dew water for fresh fruits and vegetables. Sheets for packaging used to absorb water, sheets used as base materials for absorbing cosmetic and medicinal haptics, sheets used for disposable sanitary products used for wiping sweat and sebum, and removing ammonia and amine odors, meat, etc. Absorb sap from foods such as fish and shellfish and spread the sheet in a food container to reduce ammonia and amine odors, or absorb water in advance when heating the food container with a microwave oven. Water that can be used as a source or used for various purposes such as packaging for absorbing dew water, etc. It swelled while maintaining the absorption to the original form of, and a sheet having both a deodorizing capability of the ammonia or amine malodor.

[0002]

BACKGROUND OF THE INVENTION business for cooked rice, plus immediately after raised cook
When it is placed and sealed Ji click manufactured food box making transportation, water vapor is condensed to lower the taste. In order to prevent this, a dew-water absorbing bag in which tissue paper or the like is bundled and put in a breathable nonwoven bag is placed so as to come into contact with cooked rice. In addition, a swellable sheet is used for packaging in order to absorb dew water such as fruits and vegetables.

[0003] Non-woven fabrics have been conventionally used in many cases because base materials for cosmetic and medicinal haptics and sanitary sheets for wiping sweat and sebum are required to have a liquid absorbing property, a tensile strength upon swelling and a surface strength. . About this sanitary sheet, in order to remove a bad smell such as ammonia emitted with sweat,
A swellable sheet to which a deodorant such as activated carbon or zeolite is added may be used.

[0004] Fresh food products are displayed in a film tray pack system, which is placed on a tray made of a material such as expanded polystyrene and covered with a transparent film. However, since blood juice from meat fish or the like impairs the appearance, the form of the sheet is maintained. It is common to lay a sheet that absorbs moisture between a tray and food. Further, in order to remove the odor filling the sealed tray pack, a deodorant such as activated carbon or zeolite is internally added to or coated on the sheet.

[0005]

The swellable sheet suitably used for the above-mentioned applications is obtained by forming a polymer electrolyte complex comprising a cationic water-soluble polymer on at least a part of a fibrous carboxymethylcellulose salt. (Japanese Patent Application Laid-Open No. 5-106190) has been proposed.
However, since it has no deodorizing ability, it is necessary to add or apply an adsorbent powder such as tea extract or zeolite to impart deodorant ability, but the adsorbent powder falls off Use is limited. The present invention provides a neutral swellable sheet having the same excellent liquid absorbency as the above-mentioned swellable structure, improving the surface strength when wet, and further having a deodorizing effect of ammonia / amine-based malodor. It was made to be offered.

[0006]

SUMMARY OF THE INVENTION The present invention relates to the above-mentioned Japanese Patent Application Laid-Open
The above object is achieved by laminating a surface layer having deodorization properties and improving surface strength on at least one surface of a liquid absorbing layer comprising a swellable structure as described in -106190. That is what we are trying to solve.
That is, the present invention provides a liquid-absorbing layer containing a water-absorbing fiber in which a polyelectrolyte complex with a cationic water-soluble polymer is formed on at least a part of a fibrous carboxymethylcellulose water-soluble salt; The present invention relates to a swellable laminated sheet characterized in that a surface layer containing fibrous carboxymethylcellulose cross-linked by a functional resin is laminated by laminating and joining.

In the present invention, the liquid-absorbing layer contains water-absorbing fibers formed by forming a polymer electrolyte complex with a cationic water-soluble polymer on at least a part of a fibrous carboxymethylcellulose water-soluble salt. In the liquid absorbing layer, paper-making fibers and / or fibrous carboxymethylcellulose insoluble salts are added as necessary.
The compounding amount of the fibrous carboxymethylcellulose water-soluble salt in the liquid absorbing layer is 10% by weight or more, preferably 40% by weight or more, more preferably 60% by weight or more, and the liquid absorbing layer is composed of only the water absorbing fibers. It may be something.

[0008] The fibrous carboxymethylcellulose water-soluble salt serving as a base of the water-absorbing fiber includes lithium, sodium, potassium, calcium, magnesium, ammonium salts of fibrous carboxymethylcellulose.
Alternatively, it is an amine salt such as methylamine and ethanolamine. The degree of etherification of the fibrous carboxymethylcellulose water-soluble salt is 0.1 to 1.0, preferably 0.3 to 1.0.
0.8, more preferably 0.4 to 0.6, and the base saturation (proportion of the carboxyl group converted to a salt) of the fibrous carboxymethyl cellulose water-soluble salt is 50 to 1
00%, preferably 80-100%, more preferably 9%
0 to 95%.

The cationic water-soluble polymer for forming a polyelectrolyte complex with the fibrous carboxymethylcellulose water-soluble salt is a polymer compound having a basic group in the molecule, and is a primary, secondary or tertiary compound. It is a water-soluble polymer comprising a repeating unit having at least one selected from primary and quaternary nitrogen atoms. Examples of such cationic water-soluble polymers include chitosan, a natural polymer compound,
Synthetic polymers include a polymer (1) having a primary, secondary, tertiary or quaternary nitrogen atom in the side chain of the polymer, and a primary, secondary, tertiary or quaternary in the main chain of the polymer. There is a polymer (2) having a nitrogen atom.

One example of the polymer (1) having a primary, secondary, tertiary or quaternary nitrogen atom in the side chain of the polymer is as follows: (1-a) Primary, secondary, tertiary or quaternary A homopolymer of a monomer having a secondary nitrogen atom and a polymerizable group such as a vinyl group in addition thereto, that is, a homopolymer of the following monomers. N, N-dialkylvinylamine, vinyltrialkylammonium, N-alkylaminoalkyl acrylate, N-alkylaminoalkyl methacrylate, N-alkylaminoalkylacrylamide,
N-alkylaminoalkyl methacrylamide, N,
N-dialkylaminoalkyl acrylate, N, N-
Dialkylaminoalkyl methacrylate, N, N-
Dialkylaminoalkylacrylamide, N, N-dialkylaminoalkylmethacrylamide, acryloyloxyalkyltrialkylammonium, methacryloyloxyalkyltrialkylammonium, acrylamidoalkyltrialkylammonium, methacrylamidoalkyltrialkylammonium, vinyloxyalkylamine, N-alkyl Monomers such as vinyloxyalkylamine, N, N-dialkylvinyloxyalkylamine, and N, N, N-trialkylvinyloxyalkylammonium. In these monomers, the alkyl group has 1 to 4 carbon atoms, an alkanol group may be introduced in place of the alkyl group, and instead of one alkyl group bonded to the nitrogen atom of the quaternary ammonium salt, An alkoxycarbonylalkylene group may be introduced. A specific example of the homopolymer of the above monomer is poly (methacryloyloxyethyltrimethylammonium chloride).

Another example of the polymer (1) having a primary, secondary, tertiary or quaternary nitrogen atom in the side chain of the polymer is as follows: (1-b) Primary, secondary, tertiary or quaternary A copolymer of a monomer having a graded nitrogen atom and another polymerizable group with another monomer, that is, a copolymer of the monomer described in (1-a) with another monomer. Other monomers include acrylamide, methacrylamide, acrylonitrile, methacrylonitrile, alkyl acrylate, alkyl methacrylate, vinyl acetate, styrene,
α-methylstyrene, 4-vinylpyridine, 2-vinylpyridine and the like. One specific example of the copolymer is poly (3-acrylamido-3-methylbutyltrimethylammonium chloride-CO-acrylamide).

Still another example of the polymer (1) having a primary, secondary, tertiary or quaternary nitrogen atom in the side chain of the polymer is as follows: (1-c) a homopolymer such as polyacrylamide is modified by Mannich Alternatively, some are cationized by a Hoffman decomposition reaction.

The polymer (2) having a primary, secondary, tertiary or quaternary nitrogen atom in the main chain of the polymer includes (2)
-A) ionene polymer, (2-b) polyethyleneimine, (2-c) polyamine resin in a narrow sense, (2-d) other condensation polymers.

The (2-a) ionene polymer is a polymer having an ionic amino group, particularly a quaternary ammonium group in the main chain, and most of the nitrogen atoms are quaternized. 2-ai) a polyadduct of a dihalo compound having a halogen atom at both ends of the molecule and a ditertiary amine having a tertiary nitrogen atom at both ends of the molecule, (2-a-ii) epichloro to 1 mol of the primary amine Polymerizable precursor produced by ring-opening addition of 2 mol of hydrin (third group having chlorine groups at both ends of the molecule)
Amine) and a di-tertiary amine having tertiary nitrogen atoms at both ends of the molecule, (2-a-iii) 1 mol of secondary amine is formed by ring-opening addition of 1 mol of epichlorohydrin ,
Polymers obtained by polyaddition of a compound having a chlorine atom at one molecular end and a tertiary nitrogen atom at the other molecular end.

(2-b) Polyethyleneimine is a polymer formed by ring-opening polymerization of ethyleneimine,
It has primary, secondary and tertiary nitrogen atoms in the main chain branched from the main chain.

(2-c) Although the academic definition of polyamine resin has not been established, in a narrow sense, for example, primary, secondary, and
And quaternary nitrogen atoms are defined as containing less than half of the total number of nitrogen atoms, and are distinguished from the above-mentioned ionene polymers in that they have less quaternary nitrogen atoms. Examples include: (2-ci) A polymer obtained by polycondensing a compound obtained by ring-opening addition of 1 mol of epichlorohydrin to 1 mol of primary amine while suppressing generation of a quaternary nitrogen atom.
And a hydrochloride thereof, (2-c-
ii) Polyamine resin which is a polycondensate of alkylenediamine and epichlorohydrin, and (2-c-iii) polyamine resin which is a polycondensate of alkylenediamine and alkylenedihalide.

Examples of the (2-d) other condensation polymer include (2-di) a polyamine polyamide which is a polycondensate of an alkylene polyamine and a dicarboxylic acid, for example, a polycondensate of diethylene triamine and adipic acid; d
-Ii) When epichlorohydrin and dimethylamine are further added to this polyamine polyamide, the chloro group of epichlorohydrin is added to the amide group of the polyamine polyamide to quaternize and epichlorohydrin is opened to dimethylamine. Cycloaddition results in a polymer having secondary, tertiary and quaternary nitrogen atoms in the main chain and tertiary nitrogen atoms in the side chains.

Further, in the above-mentioned chitosan, homopolymer, copolymer and modified products, the polymer obtained by quaternizing a primary, secondary or tertiary nitrogen atom with a quaternizing agent is also a cationic water-soluble polymer. It is. The quaternizing agent is capable of introducing an alkyl group or an alkoxycarbonylalkylene group into a primary, secondary, or tertiary nitrogen atom, and includes alkyl halides such as methyl chloride, ethyl chloride, and methyl bromide, dimethyl sulfate, and chlorosulfate. Methyl acetate and the like. The quaternization reaction may be carried out at the stage where the repeating unit is a monomer, followed by polymerization, or after polymerization, the repeating unit in the polymer may be quaternized by a polymer reaction.

The cationic water-soluble polymer is primary, secondary,
Other than the primary, tertiary or quaternary nitrogen atoms, highly reactive functional groups which form cross-linking, for example, glycidyl group, aldehyde group, carboxyl group, vinyl group, allyl group, N-methylol group, thiol group, isocyanate , Isothiocyanate and the like are substantially not contained. This is to prevent the cationic water-soluble polymer from forming a covalent crosslink other than forming a polyelectrolyte complex with the fibrous carboxymethylcellulose water-soluble salt. The term "substantially not contained" means that covalent crosslinking is not contained to such an extent that the formation of the polyelectrolyte complex is not inhibited or reduced.

The cationic water-soluble polymer has a cation equivalent of 0.1 to 20 meq / g, preferably 1 to 15 meq / g, and more preferably 2 to 10 meq / g when the cation equivalent is in the range of pH 3 to 9. Equivalent / g, and the (number) average molecular weight is 5,000 to 100,000, preferably 5,000 to 7,
0000, more preferably 5,000 to 20,000.

The amount of the cationic water-soluble polymer to be added to the fibrous carboxymethylcellulose water-soluble salt is within a range corresponding to 0.1 to 100% of the cation equivalent of the anion equivalent of the fibrous carboxymethylcellulose water-soluble salt. An appropriate amount is selected according to the type of the cationic water-soluble polymer. By adding the cationic water-soluble polymer in an amount within this range, a polyelectrolyte complex is formed in the fibrous carboxymethylcellulose water-soluble salt. The polyelectrolyte complex is a complex that is considered to be formed mainly through Coulomb force between a fibrous carboxymethyl cellulose water-soluble salt having opposite charges and a cationic water-soluble polymer. Although the details of the structure are not clear, the cationic water-soluble polymer is ionically cross-linked between the molecules of the fibrous carboxymethylcellulose water-soluble salt, or the cationic water-soluble polymer is added to the molecular chain of the fibrous carboxymethylcellulose water-soluble salt. Can be considered a structure or the like that is close to each other.
Due to the formation of the polyelectrolyte complex, the fibrous carboxymethylcellulose water-soluble salt, which partially dissolves and partially swells in water to form an amorphous gel, swells while maintaining the fibrous form and forms a fibrous gel. As a result, a water-absorbing fiber having both a certain level of wet strength and liquid absorbency due to the appearance of the fiber form can be obtained.

In the present invention, paper-making fibers are preferably added to the liquid-absorbing layer in addition to the water-absorbing fibers in order to improve papermaking properties, improve wet strength, and reduce costs.

The fibers for papermaking include wood pulp, non-wood pulp, dissolved pulp, plant pulp such as purified cellulose staple ("Lyocell" manufactured by Courtes Ltd., UK), semi-synthetic fiber for rayon and the like, and polyethylene. Synthetic fiber for paper making, such as polypropylene, polyester, acrylic, vinylon, polyvinyl alcohol, activated carbon fiber, etc., composite synthetic fiber for paper making composed of ethylene vinyl acetate copolymer and polypropylene, polyethylene and polypropylene, low softening point polyester and polyester These compositions improve the papermaking property and wet strength although the water absorption capacity is slightly reduced.

Another example of the papermaking fiber to be mixed in the liquid absorbing layer is a latently crimpable parallel type composite fiber in which two or more kinds of thermoplastic resins having different melting points are laminated in parallel in the fiber axis direction. This synthetic fiber has a function of forming a coil-shaped micro-crimp by heating in a temperature range between the softening points of two or more thermoplastic resins and becoming a crimpable parallel-type composite fiber. Thereafter, by performing a heat treatment under non-pressurized conditions such as hot air heating, the sheet becomes bulky and porous, and has an effect of increasing water absorption.

In order to obtain the effect of blending the papermaking fibers in the liquid absorbing layer, it is desirable to blend the papermaking fibers in an amount of 10% by weight or more. Weight% or less, desirably 60
% Or less, more preferably 20 to 60% by weight in the case of latently crimpable side-by-side conjugate fibers, and 20 to 40% by weight in the case of other papermaking fibers.

In the liquid absorbing layer, aluminum salt, iron salt,
Copper salt, cobalt salt, zinc salt, tin salt, lead salt, barium salt,
A fibrous carboxymethylcellulose insoluble salt such as a manganese salt can be blended. These fibrous carboxymethylcellulose insoluble salts have a deodorizing effect on malodorous substances. The fibrous carboxymethylcellulose-insoluble salt has a base saturation (proportion of salt among carboxyl groups) of 2 to 50%, preferably 10 to 40%, and more preferably 20 to 30%.

The amount of the fibrous carboxymethylcellulose insoluble salt in the liquid absorbing layer depends on the degree of base saturation of the fibrous carboxymethylcellulose insoluble salt, and the higher the degree of base saturation, the lower the papermaking property. There must be. 80% by weight or less when base saturation is less than 2% to 10%, base saturation is 10% to 20%
When it is less than 60% by weight, the base saturation is 20% to 30%.
%, The base saturation is 30% to 5%.
When it is less than 0%, it is at most 20% by weight.

The fibrous carboxymethylcellulose insoluble salt has high reactivity with ammonia and amine-based malodorous substances and has a strong deodorizing effect. However, since some include heavy metal salts, it is necessary to select the type of salt depending on the application. Aluminum salts or iron salts can be widely used for foods, cosmetics, miscellaneous goods, building materials and the like.

Copper salts, zinc salts, tin salts, lead salts, barium salts, etc. are used in addition to deodorizing ammonia and amine-based malodorous substances.
It has the effect of deodorizing sulfur-based malodorous substances, but is not suitable for food use. In the case of zinc salt, it can be used for cosmetics, miscellaneous goods, building materials etc. excluding food, but in the case of other salts,
It is limited to uses for miscellaneous goods or building materials.

The liquid absorbing layer may further include, if necessary,
Starch-based, polyacrylamide-based paper strength agents, humectants such as sucrose fatty acid esters, and white or colored fillers and pigments usually used for papermaking can be added.

The liquid absorbing layer composed of the above components is
The water-absorbing fiber in which the polyelectrolyte complex with the cationic water-soluble polymer is formed in at least a part of the fibrous carboxymethylcellulose water-soluble salt has a high water-absorbing ability while maintaining the sheet form, and When the fibers for use and the like are blended, the water absorption capacity is slightly reduced, but the wet strength and the papermaking property are further improved. There is no particular limitation on the basis weight of the liquid-absorbing layer.
A liquid-absorbing layer having a large basis weight can be formed by forming and mixing a plurality of wet papers with a paper net having at least two bases. In this case, for each layer constituting the liquid absorbing layer,
It is also possible to change the mixing ratio of the water-absorbing fiber and the papermaking fiber.

The present invention is characterized in that a surface layer containing fibrous carboxymethylcellulose (CMC-H) cross-linked by a polyfunctional resin is laminated on at least one surface of the liquid absorbing layer by sheet bonding. I do. If necessary, a fibrous carboxymethylcellulose insoluble salt and / or papermaking fibers are blended in the surface layer. Fibrous carboxymethylcellulose (CMC-
The compounding amount of H) is 5% by weight or more, preferably 20% by weight.
As described above, the content is more preferably 60% by weight or more, and the surface layer may be composed of only fibrous carboxymethylcellulose.

The fibrous carboxymethylcellulose (CMC-H) used for the surface layer has a carboxymethyl group of a free acid type and has a degree of etherification of 0.1 to 1.
0, preferably 0.3-0.8, more preferably 0.4
０．６0.6. Since fibrous carboxymethylcellulose has a free acid type carboxymethyl group, it is insoluble in water and does not gel, but the presence of the carboxymethyl group has high hydrophilicity and the amount of water penetrating into the fiber is also high. As compared with the vegetable pulp, the amount increases and the reactivity with the polyfunctional resin is high and a cross-linking is formed, so that high wet strength and surface strength can be easily obtained. Further, it reacts with ammonia and amine-based malodorous substances, and can remove these malodorous substances from the atmosphere in the form of fibrous carboxymethylcellulose ammonia salt and amine salt. For this reason, fibrous carboxymethylcellulose can function as a fibrous deodorant against ammonia and amine-based malodors.

In the surface layer, the polyfunctional resin used for cross-linking fibrous carboxymethylcellulose is, for example, polyamide epichlorohydrin resin, melamine resin, urea resin, etc., while melamine resin and urea resin generate formalin. Polyamide epichlorohydrin, which is used only for purposes other than food and is desirable from the viewpoint of strengthening crosslinking, may be used.

In the surface layer, in addition to the above fibrous carboxymethylcellulose, insoluble fibrous carboxymethylcellulose such as aluminum salt, iron salt, copper salt, cobalt salt, zinc salt, tin salt, lead salt, barium salt, manganese salt, etc. Salt can be added to improve the deodorizing effect. The fibrous carboxymethylcellulose-insoluble salt has a base saturation (proportion of salt among carboxyl groups) of 2 to 50.
%, Preferably 10 to 40%, more preferably 20 to 3%.
0%.

The amount of the fibrous carboxymethylcellulose insoluble salt in the surface layer depends on the base saturation of the fibrous carboxymethylcellulose insoluble salt, as in the case of the liquid absorbing layer. In order to do so, the blending amount must be reduced.
80% by weight or less when the base saturation is less than 2% to 10%,
60% by weight or less when the base saturation is less than 10% to 20%, 40% by weight when the base saturation is less than 20% to 30%
Hereinafter, when the base saturation is 30% to less than 50%, the content is 20% by weight or less.

The fibrous carboxymethylcellulose-insoluble salt has higher reactivity with ammonia and amine-based malodorous substances than fibrous carboxymethylcellulose and has a strong deodorizing effect. You need to choose. Aluminum salts or iron salts can be widely used for foods, cosmetics, miscellaneous goods, building materials and the like. Further, in the case of iron salt, there is also an effect of imparting water repellency to the surface layer, and a surface layer having excellent water resistance can be formed.

Copper salts, zinc salts, tin salts, lead salts, barium salts, etc. are used in addition to deodorizing ammonia and amine-based malodorous substances.
It has the effect of deodorizing sulfur-based malodorous substances, but is not suitable for food use. In the case of zinc salt, it can be used for cosmetics, miscellaneous goods, building materials etc. excluding food, but in the case of other salts,
It is limited to uses for miscellaneous goods or building materials.

In some cases, a fibrous carboxymethylcellulose insoluble salt is also incorporated in the liquid absorbing layer. In this case, the fibrous carboxymethylcellulose insoluble salt in the liquid absorbing layer also has a deodorizing effect.

The fibrous carboxymethylcellulose insoluble salt is also crosslinked with a polyfunctional resin such as polyamide epichlorohydrin resin, melamine resin and urea resin, like fibrous carboxymethylcellulose. Desirable as the polyfunctional resin is polyamide epichlorohydrin as described above.

[0041] Thus, the fibrous carboxymethylcellulose or fibrous carboxymethyl cellulose and the fibrous carboxymethyl cellulose insoluble salt between fibers is crosslinked by a polyfunctional resin, express high tensile strength and surface strength Oite wet And exerts a deodorizing effect on ammonia and amine-based odors.

In the present invention, the surface layer is further provided for improving papermaking properties, improving wet strength, improving water absorption, and reducing costs.
It is desirable to incorporate papermaking fibers.

The fibers for papermaking include wood pulp, non-wood pulp, dissolved pulp, plant pulp such as refined cellulose staple fiber (“Lyocell” manufactured by Courtes Ltd. of the United Kingdom), semi-synthetic fiber such as rayon, and polyethylene. Synthetic fiber for paper making, such as polypropylene, polyester, acrylic, vinylon, polyvinyl alcohol, activated carbon fiber, etc., composite synthetic fiber for paper making composed of ethylene vinyl acetate copolymer and polypropylene, polyethylene and polypropylene, low softening point polyester and polyester ,
Latent crimpable side-by-side composite fibers composed of two or more kinds of thermoplastic resins.

When blending vegetable pulp or semi-synthetic fiber as the papermaking fiber, the hydrophilicity of the surface layer is little reduced,
In order to develop wet strength, these must be cross-linked with a polyfunctional resin. In this case, since the polyfunctional resin needs to be uniformly fixed to both the fibrous carboxymethylcellulose, and the fibrous carboxymethylcellulose insoluble salt and the papermaking fiber to be blended as necessary, a mixed dispersion of these is used. It is desirable to add.

The type and blending ratio of papermaking fibers to be blended in the surface layer are determined by the desired surface strength and tensile strength in a wet state and the degree of water absorption and hydrophilicity imparted to the surface layer. In order to obtain the effect of blending the papermaking fibers in the surface layer, it is desirable to blend the papermaking fibers in an amount of 10% by weight or more, but the upper limit of the blending depends on the type of the papermaking fibers and is as follows.

In the case of vegetable pulp or semi-synthetic fiber, the compounding ratio is 95% by weight or less, preferably 50% by weight or less, more preferably 30% by weight or less.

In the case of blending synthetic fibers for papermaking and composite type synthetic fibers for papermaking, the wet strength is further improved by heat-sealing the synthetic fibers with each other, but when the blending ratio increases, the hydrophilicity of the surface layer becomes higher. Therefore, the mixing ratio in the surface layer is 80% by weight or less, preferably 60% by weight or less, and more preferably 40% by weight or less.

A latently crimpable parallel type composite fiber is blended, and after forming a sheet, non-contact type heating is performed to thermally fuse the fibers and to develop a coil-shaped micro-crimp structure, thereby forming a crimpable parallel type composite fiber. When converted to water, the sheet becomes bulky and porous, so that the amount of water absorption is improved. However, if the mixing ratio is increased, the hydrophilicity of the surface layer is reduced and the water absorption rate is reduced, so that the mixing ratio in the surface layer is 60% by weight or less. , Preferably 40% by weight
The content is more preferably 25% by weight or less.

In addition to the above-mentioned surface layer, if necessary,
Wetting agents such as starch-based, polyacrylamide-based paper strength agents, and sucrose fatty acid esters can be added. A white or colored powder commonly used for papermaking can be added, but in the case of internal addition, a coagulating / fixing agent is added together with the powder, and when the sheet becomes wet due to water absorption. ,
The powder must be prevented from falling off. Examples of the aggregating / fixing agent include polymeric aggregating / fixing agents such as polyacrylamides, sodium polyacrylates, and polyethylene glycols; and inorganic aggregating agents such as aluminum sulfate, aluminum chloride, ferric chloride, and ferric sulfate. A fixing agent, a cationic starch, a natural polymer based coagulation / fixing agent such as chitosan or the like can be used.

The surface layer composed of the above components is
Thus, fibrous carboxymethylcellulose cross-linked with a polyfunctional resin is rich in hydrophilicity, has high water absorption, exhibits high tensile strength and surface strength in a wet state, and has a deodorizing effect on ammonia and amine-based odors. Demonstrate. Furthermore, when a fibrous carboxymethylcellulose insoluble salt is blended, the deodorizing effect is even greater, and when papermaking fibers are blended, water absorption, hydrophilicity, wet strength are reinforced, and papermaking properties are improved. It has the feature of improving.

Since the surface layer needs to reinforce the low wet surface strength of the liquid absorbing layer and increase the wet strength of the entire laminated sheet, its basis weight is 5 to 30 g / m ² , preferably 10 to ² g / m ² .
0 g / m ² . When the grammage is less than 5 g / m ² , the wet strength is not sufficiently provided, and when the grammage is more than 30 g / m ² , the ratio of the surface layer to the entire laminated sheet increases, and the water absorption of the laminated sheet is undesirably reduced.

The laminated sheet has a two-layer structure in which one liquid absorbing layer is joined to one surface layer on one side, and one surface layer is formed on both sides of the single liquid absorbing layer. In addition to those having a three-layer structure joined together, a plurality of liquid-absorbing layers having different paper-making fibers and the like blended in the liquid-absorbing layer, for example, 2, 3, 4, 5
Layers can be formed into a multilayer structure in which surface layers are laminated and bonded to one or both surfaces.

To produce the swellable laminated sheet according to the present invention, at least a fibrous carboxymethylcellulose water-soluble salt is added to a dispersion of a fibrous carboxymethylcellulose water-soluble salt by adding a cationic water-soluble polymer. A water-absorbing fiber in which a polyelectrolyte complex is partially formed is prepared, and if necessary, a papermaking fiber and / or a fibrous carboxymethylcellulose insoluble salt are blended to obtain a papermaking raw material, which is then paper-formed to absorb liquid. Create layer wet paper.
In addition, a dispersion of fibrous carboxymethylcellulose or a dispersion of fibrous carboxymethylcellulose and a fibrous carboxymethylcellulose insoluble salt is blended with a polyfunctional resin for cross-linking and, if necessary, papermaking fibers. This is made into paper to form a surface layer wet paper. Combine wet paper for liquid absorption layer and wet paper for surface layer
A wet paper of a layer, a method of heating and drying the wet paper, or a wet paper of the above-mentioned liquid absorbing layer is formed into an intermediate layer and a surface layer wet paper as both outer layers to form a three-layer wet paper, It can be manufactured based on a method of heating and drying the wet paper. For the papermaking of wet paper, a papermaking technique generally used in papermaking technology described in JP-A-4-37536 can be used.

When the fibrous carboxymethylcellulose insoluble salt is blended in the liquid absorbing layer and the surface layer, the fibrous carboxymethylcellulose may be prepared by adding the fibrous carboxymethylcellulose insoluble salt to the papermaking raw material in advance. After making and drying the papermaking raw material to which
A method for producing a fibrous carboxymethylcellulose insoluble salt in a sheet by impregnating an aqueous solution of a water-soluble aluminum salt, iron salt, copper salt, cobalt salt, zinc salt, tin salt, lead salt, barium salt, manganese salt, etc. It can also be used.

As the papermaking fiber of the liquid absorbing layer or the surface layer,
When producing a sheet containing crimpable parallel type composite fibers, after blending the latent crimpable parallel type composite fibers into the papermaking raw material to form a laminated paper, a heat radiation type tunnel heat treatment machine or It is necessary to use a hot air drier and heat at a heat treatment temperature of 130 ° C. or more for 1 second or more to allow the latently crimpable side-by-side composite fibers to exhibit crimp.

[0056]

EXAMPLES Examples of the swellable laminated sheet according to the present invention will be described below. In each example, the water absorption, the wet tensile strength, the surface strength in the wet state, and the wet state of the swellable laminated sheet structure are shown. And the deodorizing ability were evaluated as follows.

<Water absorption amount> A test piece of 10 cm × 12 cm was immersed in 1000 ml of tap water for 15 minutes and then pulled up.
The excess water was dropped by hanging it with one end facing upward for 1 minute, and then the weight of the test piece was measured. The water absorption was calculated by the following equation. Water absorption (g / g) = [(test specimen weight g after removal of excess water)
-(Test piece air dry weight g)]） (Test piece air dry weight g)

<Wet tensile strength> Width 15 mm, length 2
After immersing a 00 mm test piece in tap water at 20 ° C. for 30 minutes, excess water was wiped off with a filter paper, and the tensile strength was measured with a Shopper type tensile tester.

<Surface strength in wet state> 10 cm × 10
5 drops of water were dropped on the surface of the central part of the test piece of 3 cm with a 3 ml syringe, and after the water droplets penetrated into the paper, 30
The degree of surface tearing and fluffing upon reciprocating rubbing was observed, and evaluated on a five-point scale. Surface strength 1 indicates a state in which tearing occurs and fuzzing is extremely large, surface strength 3 indicates a state in which fuzzing occurs slightly, and surface strength 5 indicates a state in which tearing and fuzzing hardly occur.

<Slimming in wet condition> 10 cm × 12 c
m was immersed in 1,000 ml of tap water for 3 minutes and then pulled up, and the feel of the surface of the test piece was organoleptically evaluated.

<Ammonia deodorizing ability> 15 cm x 20 c
m test piece was placed in a 300 ml Erlenmeyer flask, sealed with a silicone rubber stopper with a gas inlet, and ammonia standard gas was injected from the gas inlet with a gas tight syringe to set the initial gas concentration in the Erlenmeyer flask to 140000 PPM. did. One hour later, a gas detection tube manufactured by Gastech Co., Ltd. was inserted into the Erlenmeyer flask from the gas inlet, the gas concentration (PPM) in the Erlenmeyer flask was measured, and the deodorization rate was calculated from the following equation. Ammonia deodorization rate (%) = 100-Gas detector tube quantitative concentration ÷
Ammonia gas initial concentration x 100

<Trimethylamine deodorizing ability> 15 cm ×
A test piece of 20 cm was placed in a 300 ml Erlenmeyer flask, sealed with a silicone rubber stopper with a gas inlet, and trimethylamine standard gas was injected from the gas inlet with a gas tight syringe to adjust the initial gas concentration in the Erlenmeyer flask to 150 P.
PM. One hour later, a gas detection tube manufactured by Gastech Co., Ltd. was inserted into the Erlenmeyer flask from the gas inlet, the gas concentration (PPM) in the Erlenmeyer flask was measured, and the deodorization rate was calculated from the following equation. Trimethylamine deodorization rate (%) = 100-Gas detector tube quantitative concentration / Trimethylamine gas initial concentration x 100

Examples 1 to 9 Fibrous carboxymethylcellulose Na salt (CMC-Na salt) (manufactured by Nichirin Chemical Co., Ltd., degree of etherification: 0.43, base saturation: 82%)
Was dispersed in water to prepare a dispersion having a concentration of 1.5%. A polyamine resin (manufactured by Sumitomo Chemical Co., Ltd., trade name: Sumireze Resin FR-2P, number average molecular weight: 100)
Cation equivalent is 5.8 meq / g at pH 6, 4
2.0% by weight based on the fibrous carboxymethyl cellulose Na salt.
The water-absorbing fiber obtained by adding and stirring at a ratio of, and various paper-making fibers as shown in the column of the paper-making fiber of the liquid-absorbing layer in Tables 1 and 2 were blended in predetermined parts by weight, respectively. A raw material for papermaking was prepared to prepare an absorbent layer wet paper having a basis weight of 55 g / m ² .

Separately, fibrous carboxymethylcellulose (CMC-H) (manufactured by Nichirin Chemical Co., Ltd., degree of etherification: 0.43, base saturation: 0%, free acid type) and the surface layer column in Tables 1 and 2 A mixed fiber raw material prepared by mixing various kinds of papermaking fibers in a predetermined weight part and dispersing in water as shown in Fig. 4 was prepared, and a polyamide epichlorohydrin resin (trade name: WS570, manufactured by PMC Japan) was added to the mixed fiber raw material in an amount of 8 wt. %
To prepare a papermaking raw material for the surface layer, and a basis weight of 1
A surface layer wet paper of 5 g / m ² was prepared.

With the absorbent layer wet paper as an intermediate layer, the surface layer wet paper is superimposed on both sides thereof, and is passed through a filter paper for water squeezing at 3.5 kg / cm.
After pressurizing for 5 minutes at ² , it was dried by bringing it into contact with a heating mirror surface plate of a rotary dryer, and nine types of three-layered hand-made types shown in Tables 1 and 2 as Examples 1 to 9 were prepared. Paper was made.

The obtained handmade papers (Examples 1 to 9) were evaluated for water absorption, wet tensile strength, surface strength in a wet state, slimming in a wet state, and deodorizing ability. , And Table 2. For comparison, Table 2 also shows the evaluation results of a single-layer handmade paper having a basis weight of 85 g / m ² produced using the papermaking raw material of the liquid absorbing layer of Example 1 as a comparative example.

As shown in Tables 1 and 2, the three-layer handmade papers of Examples 1 to 9 have a water absorption of their own weight (basis weight of 85 g / gram).
m ² ), which is at least four times as large as that of the single-layer handmade paper of the comparative example, while showing a wet tensile strength 2 to 8 times higher than that of the comparative example. In Examples 1 to 9, the wet surface strength was broken, the fuzziness was extremely small, and the surface strength was higher than that of the comparative example. Further, Examples 1 to 9
Has a deodorization rate of 98% or more for ammonia-amine odor, and it is clear that it has an excellent deodorizing effect.

(Examples 10 to 12) A fibrous carboxymethylcellulose Na salt (manufactured by Nichirin Chemical Co., Ltd., degree of etherification: 0.43, base saturation: 82%) was dispersed in water to a concentration of 1.5%. The prepared dispersion was prepared. A water-absorbent fiber obtained by adding a cationic water-soluble polymer to the fibrous carboxymethylcellulose Na salt at a ratio of 2.0% by weight to the fibrous carboxymethylcellulose and stirring, and a latently crimpable side-by-side conjugate fiber, As shown in Table 3, a predetermined weight part was blended to prepare a liquid-absorbent layer papermaking raw material, and a liquid-absorbent layer wet paper having a basis weight of 55 g / m ² was prepared.

As the above cationic water-soluble polymer, Example 10 is a polyamine resin (Sumitomo Chemical Co., Ltd. Sumirezu Resin FR-2P, number average molecular weight 10,000, cation equivalent of 5.8 meq / pH6). g, a quaternized nitrogen atom and a tertiary nitrogen atom). Example 11
Is dissolved in an aqueous lactic acid solution so as to have a chitosan concentration of 2.5% using chitosan (Katakura Tickerin Co., Ltd., primary and secondary nitrogen atom-containing, cation equivalent 4.2 meq / g). The fibrous carboxymethyl cellulose Na
Added to salt. In Example 12, a cationic polyacrylamide resin (manufactured by Meisei Chemical Industry Co., Ltd., trade name: AG Fix M15, cation equivalent: 4.5 meq / g, containing quaternary nitrogen atom) was used.

Separately, fibrous carboxymethylcellulose (CMC-H) (manufactured by Nichirin Chemical Co., Ltd., degree of etherification: 0.43, base saturation: 0%, free acid type) and the surface layer in Table 3 are shown in Table 3. A mixed fiber raw material prepared by blending various kinds of papermaking fibers in a predetermined weight part and dispersing in water is prepared, and a polyamide epichlorohydrin resin (trade name W
S570) was added at a ratio of 8% by weight to the mixed fiber raw material to prepare a papermaking raw material for the surface layer, and the basis weight was 15 g / m ^2.
Was prepared.

Using the wet paper as the intermediate layer, the surface wet paper is superimposed on both sides of the wet paper, and is passed through a filter paper for water squeezing at 3.5 Kg / cm.
After pressing for 5 minutes at ² , it was dried by bringing it into contact with a heating mirror surface plate of a rotary drier to produce three types of three-layer handmade papers shown in Table 3 as Examples 10 to 12. did.
Next, the hand-made paper was left in a hot air drier at 160 ° C. for 30 seconds to perform a heat treatment, thereby causing the latently crimpable side-by-side conjugate fibers to exhibit crimp, and to make the sheet bulky and low in density. .

The obtained handmade papers (Examples 10 to 12) were evaluated for water absorption, wet tensile strength, surface strength in a wet state, slimming in a wet state, and deodorizing ability. It was shown to.

The three-layer handmade papers of Examples 10 to 12 had a water absorption of at least four times their own weight and showed the same water absorption as the single-layer handmade paper of the comparative example. The wet tensile strength shows a value 2-3 times higher than that of the comparative example. The wet surface strength is broken in Examples 10 to 12, has very little fluff, and has a higher surface strength than the comparative example. Further, Examples 10 to 12 have a deodorizing rate of 98% or more for the ammonia-amine type malodor, and it is clear that there is an excellent deodorizing effect.

Example 13 A fibrous carboxymethylcellulose Na salt (manufactured by Nichirin Chemical Co., Ltd., degree of etherification: 0.43, base saturation: 82%) was dispersed in water.
A dispersion having a concentration of 5% was prepared.

Further, as a cationic water-soluble polymer, a secondary amine / epichlorohydrin polyaddition polymer synthesized from dimethylamine and epichlorohydrin (average molecular weight: 8
900, a cation equivalent of 6.2 meq / g) was added at a ratio of 2.0% by weight to the fibrous carboxymethylcellulose Na salt, and 70% by weight of a water-absorbing fiber obtained by stirring, and a fiber for papermaking. 20% by weight of softwood bleached kraft pulp and 10% by weight of CMC-Zn salt, which is a fibrous carboxymethylcellulose insoluble salt, were prepared to prepare a raw material for paper making of an absorbent layer, and the absorbent having a basis weight of 55 g / m ^{2 was} prepared. A liquid layer wet paper was prepared.

Separately, 70% by weight of fibrous carboxymethylcellulose (CMC-H) (manufactured by Nichirin Chemical Co., Ltd., degree of etherification: 0.43, base saturation: 0%, free acid type) and 20% of softwood bleached kraft pulp were used. A mixed fiber material prepared by mixing 10% by weight of CMC-Al salt, which is a fibrous carboxymethylcellulose insoluble salt, and dispersing in water was prepared, and a polyamide epichlorohydrin resin (trade name: WS570, manufactured by PMC Japan) was prepared. The papermaking raw material for the surface layer was prepared by adding 8% by weight to the mixed fiber raw material to prepare a surface layer wet paper having a basis weight of 15 g / m ² .

Using the wet paper as an intermediate layer, the surface wet paper is superimposed on both sides of the wet paper, and is passed through a filter paper for water squeezing at 3.5 kg / cm.
After pressurizing for 5 minutes at ² , the mixture was brought into contact with a heating mirror surface plate of a rotary dryer and dried to produce a three-layer laminated handmade paper. The resulting handmade paper was evaluated for water absorption, wet tensile strength, surface strength in a wet state, slickness in a wet state, and deodorizing ability. The results are shown in Table 4.

(Example 14) A polyethylene polyamine resin synthesized from tetraethylenepentamine and ethylene dichloride was used as a cationic water-soluble polymer to be added to the fibrous carboxymethylcellulose Na salt of the liquid absorbing layer. Carboxymethylcellulose Na
A water-absorbing fiber obtained by adding and stirring at a ratio of 2.0% by weight with respect to the salt was used, and the constitution of the stock of the liquid-absorbing layer and the surface layer was as shown in Table 4. As in Example 13,
A three-layer laminated handmade paper was prepared.

The obtained handmade paper was evaluated for water absorption, wet tensile strength, surface strength in a wet state, slimming in a wet state, and deodorizing ability. The results are shown in Table 4.

(Example 15) A diamine / epichlorohydrin resin synthesized from hexamethylenediamine and epichlorohydrin was used as the cationic water-soluble polymer to be added to the fibrous carboxymethylcellulose Na salt of the liquid absorbing layer. In the same manner as in No. 14, a three-layer laminated handmade paper was produced.

The obtained handmade paper was evaluated for water absorption, wet tensile strength, surface strength in a wet state, slimming in a wet state, and deodorizing ability. The results are shown in Table 4.

The three-layer handmade papers of Examples 13 to 15 have a water absorption of at least four times their own weight and show the same water absorption as the single-layer handmade paper of the comparative example. The wet tensile strength is about twice as high as that of the comparative example. The wet surface strength of Examples 13 to 15 was torn, the fuzziness was extremely small, and the surface strength was higher than that of Comparative Example. further,
In Examples 13 to 15, the deodorization rate of the ammonia-amine type malodor was 99% or more, and it is clear that there was a more excellent deodorizing effect than Examples 1 to 12 in which only fibrous carboxymethylcellulose was blended.

(Examples 16 and 17) Monomethylamine, epichlorohydrin and N, N, N ', N'-tetramethyl- as the cationic water-soluble polymer added to the fibrous carboxymethylcellulose Na salt of the liquid absorbing layer.
A primary amine / epichlorohydrin / ditertiary amine polyaddition polymer (cation equivalent: 4.5 meq / g) synthesized from 1,2-diaminoethane was used. Example 1 except as shown in FIG.
In the same manner as in No. 3, a three-layer laminated type handmade paper was produced.

The handmade paper was subjected to size press coating with a 3% by weight sulfuric acid band solution. The resulting handmade paper was evaluated for water absorption, wet tensile strength, surface strength in a wet state, slickness in a wet state, and deodorizing ability. The results are shown in Table 4.

Since the sulfuric acid band reacts with fibrous carboxymethylcellulose to produce fibrous carboxymethylcellulose aluminum salt, the deodorizing effect on ammonia and trimethylamine is excellent as in the case of fibrous carboxymethylcellulose aluminum salt. A secondary effect is seen with increasing wet surface strength.

Example 18 A fibrous carboxymethyl cellulose Na salt (manufactured by Nichirin Chemical Co., Ltd., degree of etherification: 0.43, base saturation: 82%) was dispersed in water.
A dispersion having a concentration of 5% was prepared. Polyethylene imine resin (manufactured by Nippon Shokubai Chemical Co., Ltd., trade name Epomin SP200, number average molecular weight 20,000, branched structure,
80% by weight of water-absorbing fibers obtained by adding and stirring 2.0% by weight with respect to the Na salt of the fibrous carboxymethylcellulose, and conifer as papermaking fibers. 20% by weight of the bleached kraft pulp was blended to prepare a liquid absorbing layer papermaking raw material to prepare a liquid absorbing layer wet paper B having a basis weight of 55 g / m ² .

Separately, 10% by weight of fibrous carboxymethylcellulose (manufactured by Nichirin Chemical Co., Ltd., degree of etherification: 0.43, base saturation: 0%, free acid type), 10% by weight of softwood bleached kraft pulp, and fibrous carboxymethylcellulose CMC-Fe (II) as a salt (base saturation 8%) 8
A mixed fiber material prepared by mixing 0% by weight and dispersing in water is prepared, and a polyamide epichlorohydrin resin (trade name: WS570, manufactured by PMC Japan) is added to the mixed fiber material at a ratio of 8% by weight based on the mixed fiber material. The papermaking raw material of the layer A was prepared to prepare a surface layer wet paper A having a basis weight of 15 g / m ² .

Separately, fibrous carboxymethylcellulose (manufactured by Nichirin Chemical Co., Ltd., having a degree of etherification of 0.43,
A mixed fiber raw material prepared by mixing 70% by weight of base saturation and 0% by weight of free acid type and 30% by weight of softwood bleached kraft pulp and dispersing in water was prepared, and a polyamide epichlorohydrin resin (trade name: WS570, manufactured by PMC Japan) was prepared. ) Was added at a ratio of 8% by weight to the mixed fiber raw material to prepare a papermaking raw material for the surface layer C, thereby producing a surface layer wet paper C having a basis weight of 15 g / m ² .

With the liquid absorbing layer wet paper B as an intermediate layer, the surface layer wet paper A is superimposed on one surface and the surface layer wet paper C is superimposed on the other surface, and 3.5 kg / cm ² through a filter paper for water squeezing. After pressurizing for 5 minutes, the mixture was dried by bringing it into contact with a heating mirror surface plate of a rotary dryer to prepare a three-layer laminated handmade paper laminated in an ABC arrangement.

The obtained handmade paper was evaluated for water absorption, wet tensile strength, surface strength in a wet state, slimming in a wet state, and deodorizing ability. The results are shown in Table 5.

The three-layered handmade paper of Example 18 had a water absorption of at least four times its own weight and showed the same water absorption as the single-layer handmade paper of the comparative example. The tensile strength is about twice as high as that of the comparative example. The wet surface strength of Example 18 was extremely low in tearing and fuzzing, and was higher than that of Comparative Example. Furthermore, Example 18 has a deodorization rate of 99% or more of the ammonia-amine type malodor, and it is clear that there is a more excellent deodorizing effect than Examples 1 to 12.

Further, when water was dropped on the surface layer A due to the water repellency of the CMC-Fe (II) salt, the water was repelled as water drops and did not permeate the paper for several hours. When water was dropped on the surface layer C, the water droplets were immediately absorbed into the paper, and no water repellency was observed. For this reason, it is clear that the three-layer handmade paper of Example 18 has two faces, one face being hydrophilic and the other face being water repellent.

[0093]

[Table 1]

[0094]

[Table 2]

[0095]

[Table 3]

[0096]

[Table 4]

[0097]

[Table 5]

[0098]

The swellable laminated sheet of the present invention exhibits a high water absorption while maintaining the sheet form and has a high tensile strength and a high surface strength even in a wet state after absorbing the liquid. It can be used in a wide range of fields as needed. Further, since it has a deodorizing effect on malodorous substances, it can be used for various applications requiring liquid absorption and deodorization.

Claims (8)

(57) [Claims] 1. A liquid-absorbing layer containing a water-absorbing fiber in which a polyelectrolyte complex with a cationic water-soluble polymer is formed on at least a part of a fibrous carboxymethylcellulose water-soluble salt; A swellable laminated sheet comprising a surface layer containing fibrous carboxymethylcellulose cross-linked by a water-soluble resin, which is laminated by sheet bonding. 2. The swellable laminated sheet according to claim 1, wherein the liquid absorbing layer contains papermaking fibers. 3. The swellable laminated sheet according to claim 1, wherein the surface layer contains papermaking fibers. 4. The swellable laminated sheet according to claim 2, wherein the papermaking fibers are at least one selected from vegetable pulp, semi-synthetic fibers and synthetic fibers. 5. The swellable laminated sheet according to claim 1, wherein the liquid absorbing layer contains a fibrous carboxymethylcellulose insoluble salt. 6. The swellable laminated sheet according to claim 1, wherein the surface layer contains a fibrous carboxymethylcellulose insoluble salt. 7. The swellable laminated sheet according to claim 5, wherein the fibrous carboxymethylcellulose insoluble salt is an aluminum salt, an iron salt or a zinc salt of fibrous carboxymethylcellulose. 8. The cationic water-soluble polymer is chitosan, a polymer having a primary, secondary, tertiary or quaternary nitrogen atom in the side chain of the polymer, and a primary, secondary or tertiary polymer in the main chain of the polymer. The swellable laminated sheet according to any one of claims 1 to 7, wherein the swellable laminated sheet is at least one selected from polymers having a quaternary or quaternary nitrogen atom.