JP2001081697A - Modifier for paper, paper and production of paper - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a modifier for paper, suitable as an improver of an interlaminar strength, and an improver of a paper strength such as a burst strength for a multilayered combination paper by formulating a water-soluble polysaccharides at least containing alginic acid with an acrylamide-based polymer. SOLUTION: This modifier for paper comprising at least 0.1-50 wt.% water-soluble polysaccharides at least containing alginic acid, and 99.9-50 wt.% (meth) acrylamide-based polymer. The water-soluble saccharides at least containing the alginic acid are obtained by copolymerizing (meth)acrylamide with a cationic vinyl monomer, e.g. (dimethylaminoethyl (meth)acrylate and a polyfunctional vinyl monomer, e.g. di(meth)acrylate in the presence of the water-soluble polysaccharides at least containing the alginic acid to provide the (meth) acrylamide-based polymer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a method for producing a multilayer paper, for example, when applying a wet paper web to a wet paper web before spraying the wet paper web by spraying. In the case of paper making, paper strength such as internal bond strength and burst strength can be increased by increasing the paper strength such as interlayer strength and burst strength, or by adding paper to pulp slurry when making paper and making paper. The present invention relates to a paper modifier such as a paper strength improver capable of increasing the paper strength, a paper containing the components, and a method for producing the paper.

[0002]

2. Description of the Related Art Conventionally, thick paper which cannot be obtained by single-layer papermaking such as cardboard base paper and paperboard is manufactured by so-called multi-layer papermaking, in which a plurality of wet papers are bonded together. I have. In the case of producing a multilayer paper, in order to increase the interlayer strength, after spraying ungelatinized starch on the surface of the obtained wet paper, a plurality of wet papers are combined. This aqueous slurry of starch is known as a so-called interlayer strength improver. However, when using an aqueous slurry of starch, sufficient interlaminar strength cannot be obtained, and the aqueous slurry is prepared by dissolving starch powder in water. Further, a part of the slurry is mixed into the white water due to the pressure at which the slurry is sprayed on wet paper and mixed together. This white water may be used in a circulating manner, but eventually it will be degraded when it is disposed of in rivers, sea, etc., so it will be treated by the activated sludge method. There is a problem.

[0003] In order to solve the problems when using the aqueous slurry of starch, it has been proposed to use an aqueous solution of an acrylamide-based polymer.
157999 discloses a method using an acrylamide-based copolymer obtained by copolymerizing acrylamide, an ionic monomer and a crosslinkable monomer. JP-A-10-183497 discloses a method in which acrylamide or the like is copolymerized in the presence of starch, and an acrylamide-based copolymer and an interlayer strength improver containing starch are used.

[0004] Not only when obtaining such a multi-layer paper but also when obtaining a single-layer paper, by adding an acrylamide-based polymer to the pulp slurry and making the paper, so-called internal strength is obtained. It has also been done to increase.

[0005]

However, in the case where the acrylamide-based polymer proposed so far alone is internally added alone, pulp fibers are excessively agglomerated at the time of paper making to disturb the formation of the paper. The paper strength improving effects such as the burst strength improving effect and the internal bond strength improving effect cannot be sufficiently obtained. In addition, in the case of a multilayer paper, not only the sufficient effect of improving the interlayer strength is not obtained, but also an acrylamide-based copolymer obtained by copolymerizing acrylamide or the like in the presence of starch,
The starch in the product precipitates during storage and preservation of the product due to the aging phenomenon inherent in the starch, which is problematic in terms of product stability. In addition, in recent years, in order to improve the quality of paper, in addition to the interlaminar strength of the multi-layered paper, the paper penetrating into the paper layer so that the paper strength in the paper layer can be increased and the burst strength etc. Although there is a demand for an interlayer strength improver that also improves the strength,
At present, an interlayer strength improver that increases both the interlayer strength and the paper strength such as burst strength has not yet been developed.

A first object of the present invention is to provide a paper modifier obtained by a novel combination of existing materials, a paper containing its components, and a method for producing the paper. The second object of the present invention is not only as an interlaminar strength improver for a multi-layered paper, but also as a paper strength improver, having a single or combined function, and also being effective as another internally added paper strength improver. An object of the present invention is to provide a paper modifier, paper containing the components thereof, and a method for producing the paper. A third object of the present invention is to provide a paper modifier having excellent product stability, a paper containing the components, and a method for producing the paper. A fourth object of the present invention is to provide a paper modifying agent containing a paper modifying agent which is easy to prepare a paper modifying agent-containing liquid containing a paper modifying agent, and which easily performs wastewater treatment by the activated sludge method. And a method for producing the paper. A fifth object of the present invention is to improve the paper strength irrespective of whether it is a multi-layered paper or a single-layered paper, and to improve the production and use of the paper, An object of the present invention is to provide a paper containing the component and a method for producing the paper.

[0007]

The present inventors have conducted intensive studies to solve the above-mentioned problems. As a result, (i) water-soluble polysaccharide (A) containing alginic acid and at least acrylamide (b1) The composition containing the acrylamide-based polymer (B) obtained by polymerizing the monomer containing the compound (A) has a higher interlayer strength and paper strength than a conventional interlayer strength improver as an interlayer strength improver for a multilayer paper. A composition containing (ii) a water-soluble polysaccharide (A) containing alginic acids and an acrylamide-based polymer (B) obtained by polymerizing a monomer containing at least acrylamides (b1) by internal addition; It has been found that when added to a pulp slurry as a paper strength improver, paper strength such as superior burst strength and internal bond strength is superior to conventional paper strength improvers, and the present invention has been completed. In order to solve the above-mentioned problems, the present invention provides (1) a water-soluble polysaccharide (A) containing at least alginic acid, and at least an acrylamide (b)
A paper modifier containing an acrylamide-based polymer (B) obtained by polymerizing a monomer containing 1), (2) a water-soluble polysaccharide containing at least alginic acid (A),
The acrylamide-based polymer (B) obtained by polymerizing a monomer containing at least an acrylamide (b1) is a separate body, and the above-mentioned (1) containing a mixture of both.
(3), an acrylamide-based polymer (B) obtained by polymerizing a monomer containing at least acrylamide (b1) in the presence of a water-soluble polysaccharide (A) containing at least alginic acid Obtained by polymerization with
A paper modifier containing the reaction product of the components (A) and (B), (4) at least an acrylamide (b)
The acrylamide-based polymer (B) obtained by polymerizing a monomer containing 1) is a polymer obtained by copolymerizing a monomer containing an acrylamide (b1) and a cationic vinyl monomer (b2) (1). Or (3)
The acrylamide-based polymer (B) obtained by polymerizing a monomer containing at least one of the paper modifier (5) and acrylamide (b1) is an acrylamide (b)
1) A paper modifier according to any one of the above (1) to (3), which is a polymer obtained by copolymerizing a monomer containing a cationic vinyl monomer (b2) and a polyfunctional vinyl monomer (b3). , (6), an acrylamide-based polymer (B) obtained by polymerizing a monomer containing at least an acrylamide (b1) is an acrylamide (b)
1) a paper modifier according to any one of the above (1) to (3), which is a polymer obtained by copolymerizing a monomer containing a cationic vinyl monomer (b2) and an anionic vinyl monomer (b4); (7) An acrylamide-based polymer (B) obtained by polymerizing a monomer containing at least an acrylamide (b1) is an acrylamide (b)
1) a polymer obtained by copolymerizing a monomer containing a cationic vinyl monomer (b2), a polyfunctional vinyl monomer (b3) and an anionic vinyl monomer (b4); Any of the paper modifiers (8) is obtained by polymerizing a monomer containing at least 0.1 to 50% by weight of a water-soluble polysaccharide (A) containing at least alginic acid and at least acrylamide (b1). The paper modifier according to any one of the above (1) to (7), wherein the acrylamide polymer (B) is 99.9 to 50% by weight, (9), any one of the above (1) to (8) Water-soluble polysaccharide containing at least alginic acid (A)
And an acrylamide-based polymer (B) obtained by polymerizing a monomer containing at least an acrylamide (b1)
A paper containing (10), a coating liquid containing the paper modifier of any of the above (1) to (8) is coated on the surface of the prepared wet paper to form a plurality of wet papers. A method for producing a paper for producing a multilayer paper by using the paper modifier as an interlayer strength improver, (11), the paper according to the above (10), wherein the interlayer strength improver contains a calcium compound; Manufacturing method,
(12) The method for producing paper according to the above (10) or (11), wherein any of the plurality of wet papers contains calcium carbonate;
(13) The water-soluble polysaccharide (A) containing at least alginic acid according to any one of the above (1) to (8)
And an acrylamide-based polymer (B) obtained by polymerizing a monomer containing at least an acrylamide (b1)
And (14) a method of making a paper by adding the paper modifier of any of the above (1) to (8) to the pulp slurry. A method for producing paper is provided.

In the present invention, the water-soluble polysaccharide (A) containing alginic acid may be only alginic acid,
This is preferred, but it means that alginic acids may be used in combination with various starches such as cationized starch, amphoteric starch, oxidized starch, and other water-soluble polysaccharides such as mannan, carboxymethyl cellulose (CMC), and chitosan. Alginic acids are known as anionic polysaccharides,
It becomes jelly-like due to the presence of calcium ions and is widely used in the food field. However, examples of the use of alginic acids in papermaking applications include, for example, adding to a coating liquid applied to the surface of a paper for glossing, such as gravure printing paper, and the water of the coating liquid is applied to the paper. Suppresses the rate of absorption, making it easier for other components to remain on the paper surface with moisture,
Applications for improving the so-called water retention are known, and Japanese Patent Application Laid-Open No. Hei 9-13010 discloses a method of using together with an anti-slip agent such as, for example, a granular synthetic polymer, in order to make the surface of the formed paper less slippery. Only a method of improving the film-forming property so that the anti-slip agent does not penetrate into the formed paper and easily stays on the surface has been proposed. As a matter of course, it is not known that alginic acids are added to a pulp slurry in a papermaking process and used as a component of an internal additive or used in other papermaking applications.

In the present invention, alginic acids ("(A)
Component ". ) Are not particularly limited, for example, alginic acid, alkali metal salts of alginic acid such as sodium alginate, potassium alginate, alkaline earth metal salts of alginic acid such as calcium alginate,
At least one salt such as amine salts of alginic acid such as ammonium alginate, salts such as heavy metal salts of alginic acid such as zinc alginate, polyhydric alcohol esters of alginic acid such as propylene glycol alginate, modified alginic acid such as triethanolamine alginate, and salts thereof. Seeds. Preferred among these are
Sodium alginate.

In the present invention, the acrylamide-based polymer (sometimes referred to as “component (B)”) includes:
At least acrylamides may be referred to as “component (b1)”. ) As a polymerization component. As the acrylamides, for example, in addition to (meth) acrylamide (which means at least one of methacrylamide and acrylamide, and hereinafter “(meth)” is used correspondingly), N-methyl (meth) acrylamide, N-ethyl (meth) acrylamide, N, N-dimethyl (meth) acrylamide, N, N-diethyl (meth) acrylamide, N-isopropyl (meth) acrylamide, Nt
N-substituted (meth) such as octyl (meth) acrylamide
Acrylamide and the like can be mentioned, and these may be used alone or in combination of two or more. Of these, (meth) acrylamide is particularly preferred.

Other monomers that can be copolymerized with the acrylamides include cationic vinyl monomers (sometimes referred to as "component (b2)"). Examples of the cationic vinyl monomer include dialkylaminoalkyl alcohols such as dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, dimethylaminopropyl (meth) acrylate, and diethylaminopropyl (meth) acrylate, and (meth) acrylic acid. Dialkylaminoalkyl (meth) acrylates such as dimethylaminopropyl (meth) acrylamide, diethylaminopropyl (meth) acrylamide, etc., and alkyl diallylamine, dialkylallylamine, diallylamine, allylamine, etc. Amino group-containing vinyl monomers such as allylamines (“tertiary amino group-containing vinyl monomers, secondary amino group-containing vinyl monomers ), Salts of inorganic or organic acids such as hydrochloric acid, sulfuric acid, formic acid, and acetic acid of the amino group-containing vinyl monomer, and tertiary amino group-containing vinyl monomers. Monomers and alkyl halides such as methyl chloride and methyl bromide, aralkyl halides such as benzyl chloride and benzyl bromide, dimethyl sulfate, diethyl sulfate, epichlorohydrin, 3-chloro-2-hydroxypropyltrimethylammonium chloride, glycidyltrialkylammonium chloride And the like. A vinyl monomer containing a quaternary ammonium salt obtained by a reaction with a quaternizing agent such as 2-hydroxyN, N, N, N, N ', N'-pentamethyl-N'-[3-{(1- Oxo-2-propenyl) amino Propyl] -1,3-propanediol Zia mini um dichloride and the like can be exemplified, and these may be used alone or in combination of two or more.

The other monomer which can be copolymerized with the acrylamides also includes a polyfunctional vinyl monomer (sometimes referred to as "component (b3)"). Examples of the polyfunctional vinyl monomer include di (meth) acrylates, bis (meth) acrylamides, and divinyl esters.
Functional vinyl monomers, epoxy acrylates, urethane acrylates, trifunctional vinyl monomers, tetrafunctional vinyl monomers, water-soluble aziridinyl compounds, and the like can be used. These may be used alone or may be used alone.
More than one species may be used in combination. Examples of the polyfunctional vinyl monomer include, in addition to the above, a water-soluble polyfunctional epoxy compound and a silicon-based compound. These may be used alone or in combination of two or more. You may. Examples of the di (meth) acrylates include ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, and glycerin di (meth) acrylate. Acrylates and the like can be mentioned, and these may be used alone or in combination of two or more. Examples of the bis (meth) acrylamides include methylenebis (meth) acrylamide, ethylenebis (meth) acrylamide, hexamethylenebis (meth) acrylamide, N, N′-bisacrylamideacetic acid, and N, N′-bisacrylamidoacetate. , N, N-benzylidenebisacrylamide and the like, and these may be used alone or in combination of two or more. Examples of the divinyl esters include divinyl adipate and divinyl sebacate. These may be used alone or in combination of two or more. Other polyfunctional vinyl monomers include, for example, allyl (meth) acrylate, diallyl phthalate, diallyl maleate, diallyl succinate, diallyl acrylamide, divinylbenzene, diisopropenylbenzene, N, N-diallyl methacrylamide, N −
Methylol acrylamide, diallyldimethylammonium, diallylchlorendate, glycidyl (meth) acrylate and the like can be mentioned, and these may be used alone or in combination of two or more.

The trifunctional vinyl monomer includes, for example, 1,3,5-triacryloylhexahydro-S
-Triazine, triallyl isocyanurate, N, N-
Examples thereof include diallyl acrylamide, triallylamine, triallyl trimellitate, and the like. These may be used alone or in combination of two or more. Examples of the tetrafunctional vinyl monomer include, for example, tetramethylolmethanetetraacrylate, tetraallyl pyromellitate, N, N, N ′, N′-tetraallyl-1,4
-Diaminobutane, tetraallylamine salt, tetraallyloxyethane and the like can be mentioned, and these may be used alone or in combination of two or more. Examples of the water-soluble aziridinyl compound include tetramethylolmethane-tri-β-aziridinylpropionate, trimethylolpropane-tri-β-aziridinylpropionate, 4,4′-bis (ethyleneiminecarbonyl Amino) diphenylmethane and the like can be mentioned, and these may be used alone or in combination of two or more. Examples of the water-soluble polyfunctional epoxy compound include (poly) ethylene glycol diglycidyl ether, (poly) propylene glycol diglycidyl ether, (poly) glycerin diglycidyl ether,
Examples thereof include (poly) glycerin triglycidyl ether, and these may be used alone or in combination of two or more. Examples of the silicon-based compound include 3- (meth) acryloxymethyltrimethoxysilane, 3- (meth) acryloxypropyldimethoxymethylsilane, 3- (meth) acryloxypropyltrimethoxysilane, and 3- (meth) Acryloxypropylmethyldichlorosilane, 3- (meth) acryloxyoctadecyltriacetoxysilane, 3- (meth) acryloxy-2,5-dimethylhexyldiacetoxymethylsilane, vinyldimethylacetoxysilane and the like can be mentioned. One type may be used alone, or two or more types may be used in combination.

Other monomers that can be copolymerized with the acrylamides include anionic vinyl monomers (sometimes referred to as "component (b4)"). Examples of the anionic vinyl monomer include a carboxyl group-containing vinyl monomer, a sulfonic acid group-containing vinyl monomer, and a phosphonic acid group (-PO
At least one kind of (OH) ₂ ) -containing vinyl monomer can be used. Examples of the carboxyl group-containing vinyl monomer include unsaturated monocarboxylic acids, unsaturated dicarboxylic acids, unsaturated tricarboxylic acids, and unsaturated tetracarboxylic acids, and salts thereof, and the like. Unsaturated sulfonic acids and the like and salts thereof can be mentioned. Examples of the phosphonic acid group-containing vinyl monomer include unsaturated phosphonic acids and the like and salts thereof, and these can be used alone. Or two or more of them may be used in combination. Examples of the unsaturated monocarboxylic acid include acrylic acid and methacrylic acid.Examples of the salts of the unsaturated monocarboxylic acid include alkali metal salts such as a sodium salt and a potassium salt of an unsaturated carboxylic acid, and ammonium salts. These may be used alone or in combination of two or more. Specific examples of the unsaturated dicarboxylic acid include, for example, maleic acid, fumaric acid, itaconic acid, citraconic acid, and the like.Specific examples of the unsaturated dicarboxylic acid salts include:
Examples thereof include alkali metal salts such as a sodium salt and a potassium salt of an unsaturated dicarboxylic acid, and an ammonium salt. These may be used alone or may be used alone.
More than one species may be used in combination. Specific examples of the unsaturated tricarboxylic acid include aconitic acid and 3-butene-
1,2,3-tricarboxylic acid, 4-pentene-1,2,
Examples of the salts of unsaturated tricarboxylic acids include, for example, sodium salts of unsaturated tricarboxylic acids, alkali metal salts such as potassium salts, and ammonium salts.
These may be used alone or in combination of two or more.

Specific examples of the unsaturated tetracarboxylic acid include 1-pentene-1,1,4,4-tetracarboxylic acid, 4-pentene-1,2,3,4-tetracarboxylic acid, and 3-pentene-1,2,3,4-tetracarboxylic acid. Hexene-1,1,6,6-tetracarboxylic acid and the like. Specific examples of the salts of the unsaturated tetracarboxylic acid include alkali metal such as sodium salt and potassium salt of the unsaturated tetracarboxylic acid. Salts and ammonium salts, and the like.
One type may be used alone, or two or more types may be used in combination. Specific examples of the unsaturated sulfonic acid include vinyl sulfonic acid, styrene sulfonic acid, (meth) allyl sulfonic acid, and 2-acrylamido-2-methylpropane sulfonic acid. Specific examples of the salt include alkali metal salts such as sodium salt and potassium salt of unsaturated sulfonic acid, and ammonium salt. These may be used alone or in combination of two or more. You may use together. Specific examples of the unsaturated phosphonic acid include, for example, vinylphosphonic acid and α-phenylvinylphosphonic acid, and specific examples of the salts of the unsaturated phosphonic acid include sodium salts of the unsaturated phosphonic acid. Examples thereof include alkali metal salts such as salts and potassium salts, and ammonium salts. These may be used alone or in combination of two or more. The anionic vinyl monomer is preferably at least one selected from the group consisting of unsaturated monocarboxylic acids, unsaturated dicarboxylic acids and salts thereof, for example, from the viewpoints of paper quality improving effect and economy, and particularly, itaconic acid, acrylic At least one selected from the group consisting of acids and salts thereof is particularly preferred. The combined use of an acrylamide-based polymer obtained by copolymerizing an anionic vinyl monomer and alginic acids can maintain the desired degree of anionization as a whole and reduce the cost even if the amount of the alginic acids of the anionic polysaccharide is reduced. There are benefits.

Other monomers that can be copolymerized with the acrylamides include nonionic vinyl monomers (sometimes referred to as "component (b5)"). Examples of the nonionic vinyl monomer include an ester of alcohol and (meth) acrylic acid, (meth) acrylonitrile, styrene, a styrene derivative, vinyl acetate, vinyl propionate, and methyl vinyl ether. Or two or more of them may be used in combination.

In the present invention, the water-soluble polysaccharide (A) containing at least alginic acid and the acrylamide-based polymer (B) obtained by polymerizing a monomer containing at least acrylamide (b1) are separate bodies. It may be a paper modifier containing a mixture of both, or a paper modifier containing the reaction product of both, the latter is applied to wet paper to obtain a multilayer paper The former is preferred when paper is added to the pulp slurry and paper is obtained by so-called internal addition. When paper is obtained by internal addition, not only the case where the components (A) and (B) are simultaneously added to the pulp slurry, but also the locations where the components are separately added to the pulp slurry, the time of addition, or both are changed. May be. In the case of multi-layer making, a multi-layer making paper may be produced using internally added wet paper. Although the inventions of the above (13) and (14) include these cases, the "papermaking method" and thereafter are followed by the "method of producing paper for producing a multi-layer papermaking by making papermaking and combining a plurality of wet papers". It may be. The amount of the component (A) and the component (B) and the amount of each of the components (b1) to (b5) are determined according to the composition containing the obtained copolymer, the component (A) and the component (B).
The paper strength such as interlayer strength, burst strength, and internal bond strength can be determined by sufficiently considering the paper strength and other properties such as interlayer strength, burst strength, and internal bond strength when a mixture of components is used. In terms of force, component (A) is 0.1 to 50% by weight, component (B) is 99.9 to 50% by weight ((b1) to
(B5) The sum of the weights of the respective monomers of the component is 99.9 to 50.
% By weight). The components (A) and (B) can each be made water-soluble, and a mixture or reaction product of both components can also be made water-soluble. When the amount of the component (A) is less than 0.1% by weight,
The paper strength such as interlayer strength, burst strength, and internal bond strength may decrease. When the component (A) exceeds 50% by weight, the paper strength such as interlayer strength, burst strength, and internal bond strength decreases. In some cases, and the cost tends to be high.

The amount of each monomer in the comonomer composed of each of the components (b1) to (b5) is as follows:
(i) When the component (b5) is 0, the components (b1) to (b1)
(B4), (ii) each component of (b3) and (b5) is 0
At the time of (b1), (b2), (b4), (iii)
When each of the components (b4) and (b5) is 0, (b1) to (b3), and (iV) when each of the components (b3) to (b5) is 0, the (b1) (B2), (v) When each of the components (b2) to (b5) is 0, the above (b)
A comonomer or monomer composed of each monomer of 1) will be used. In the case of the above (i), the component (b1) usually contains 100 to 50 mol%, preferably 99.59 to 99 mol%.
65 mol%, the component (b2) is usually 0 to 20 mol%,
Preferably 0.2 to 15 mol%, the component (b3) is usually 0 to 10 mol%, preferably 0.01 to 5 mol%, and the component (b4) is usually 0 to 20 mol%, preferably 0.1 to 10 mol%.
1 to 15 mol%. In the case of the above (ii), the above (b)
1) The component is usually 100 to 60 mol%, preferably 99.
7 to 70 mol%, the component (b2) is usually 0 to 20 mol%, preferably 0.2 to 15 mol%, and the component (b4) is usually 0 to 20 mol%, preferably 0.1 to 15 mol%. %
It is. In the case of the above (iii), the component (b1) is usually 100 to 60 mol%, preferably 99.79 to 75 mol%, and the component (b2) is usually 0 to 25 mol%, preferably 0.2 to 0.2 mol%. ~ 20 mol%, the component (b3) is usually 0 ~
It is 15 mol%, preferably 0.01 to 5 mol%. In the case of the above (iv), the component (b1) is usually 100 to 7
0 mol%, preferably 99.8 to 80 mol%, (b)
2) The component is usually 0 to 30 mol%, preferably 0.2 to 2 mol%.
0 mol%. In the case of the above (v), only the component (b1) is contained. The component (b5) includes the components (b1) to (b).
0 to 40 mol%, preferably 0 to 20 mol%, based on 100 mol% in total of 4). Further, the above monomer ratio indicates the final ratio of the monomers, and all the monomers may be charged and reacted together, or all the monomers may be charged by dividing a part or all of the composition. The reaction may be carried out, or all of the monomers may be continuously dropped, or part or all of the composition may be continuously dropped on the remaining ones. Within such a range, when the composition containing the component (A) and the component (B) is used as an interlayer strength improver, not only sufficient interlayer strength but also this composition is contained in the paper layer. , The burst strength (paper strength) can be more effectively exerted. When a composition containing these components (A) and (B) is added to a pulp slurry and used, the paper strength such as burst strength and internal bond strength is more effectively exhibited. Can be.

In the present invention, in order to prepare a composition containing a reaction product of both components by reacting the above-mentioned component (B) in the presence of the above-mentioned component (A), there are known various other methods. Can be applied. For example, (i) a cerium salt, an azo compound such as AIBN, or benzoyl peroxide, hydrogen peroxide,
A redox system comprising peroxides such as sodium persulfate, potassium persulfate and ammonium persulfate, or a combination of these peroxides with a reducing agent such as sodium bisulfite
Examples thereof include a method using a polymerization initiator, and (ii) a method of irradiating radiation, an electron beam, ultraviolet light, or the like. According to these production methods, a reaction product in which the component (A) and the component (B) are combined is obtained, and the reaction product can be referred to as a water-soluble polymer. Included in it. As the graft polymer, a structure obtained by grafting a polymer obtained by polymerizing the monomer (b1) or the monomer selected from (b1) and (b2) to (b5) onto the component (A) is considered. Can be The polymer of the component (B) can be obtained in the same manner except that the component (A) is not used.
The polymerization reaction is usually carried out by the component (A), (b1) and (b).
The polymerization initiator is added to a mixed aqueous solution of the monomers selected from 2) to (b5), and in the presence of an inert gas, usually at 35 to 100 ° C, preferably at 45 to 95 ° C, for 1 to 10
This is carried out by heating and stirring for an hour. With such a reaction temperature, the polymerization initiator and the monomer can be appropriately added, the whole components can be divided, and the reaction can be performed in multiple stages.
For example, a polymerization initiator is added to the aqueous monomer solution, and 65 to 9
After polymerizing the prepolymer at 0 ° C., the remaining monomer can be further added to carry out the polymerization reaction.

In the present invention, when a reaction product obtained by combining the above-mentioned component (A) and the above-mentioned component (B), for example, a composition containing a water-soluble polymer is used, each of the above-mentioned components (A) is separately formed. When applied to wet paper, the effect of improving the interlayer strength and the effect of improving the paper strength such as bursting strength are increased as compared with the case where the composition obtained by mixing the components and the component (B) is used. Both are included in the present invention. Even in the latter case, the effect of improving the interlaminar strength and the effect of improving the paper strength such as the burst strength are higher than when the component (A) alone or the component (B) is used alone. Although it is not clear why the reaction product is superior in paper strength such as interlaminar strength and burst strength as compared to the case of using a simple mixture,
It is considered that the synergistic effect of the alginic acid component (A) and the polymer component (B) was achieved by grafting. In addition, when used internally by adding to the pulp slurry, the reaction product obtained by combining the component (A) and the component (B), for example, a composition containing a water-soluble polymer is used. When a composition obtained by mixing the above-mentioned components (A) and (B) separately is used, the effect of improving paper strength such as burst strength and internal bond strength is improved. Are included in the present invention. Even in the former case, the effect of improving paper strength such as burst strength and internal bond strength is higher than when the above-mentioned component (A) alone or the above-mentioned component (B) alone is used, but the reason for this is not clear.

For example, a water-soluble polymer as a reaction product obtained by combining the above-mentioned component (A) and the above-mentioned component (B) can be obtained by conducting the above-mentioned polymerization reaction. In this case, a polymerization reaction solution containing the water-soluble polymer can be obtained, and this can be used as it is or by mixing other additives to improve the interlayer strength or rupture. It can be a coating liquid for a paper strength improver such as strength or an additive liquid for internal addition to a pulp slurry. Further, after the water-soluble polymer is isolated from the polymerization reaction product solution and purified, the water-soluble polymer can be used for an appropriate use.

The alginic acid as the component (A) is composed of 2
It is known that a crosslinked structure is formed via a cation having a valence of at least. In the present invention, the reaction product obtained by combining the component (A) and the component (B) or the component (A) is It is considered that the mixture of the component (B) also forms a crosslinked structure, thereby improving the paper strength of the multilayered paper such as interlayer strength and burst strength, and the paper strength of internally added paper such as internal bond strength. Therefore, it is preferable to use a divalent or higher cation in combination. 2
Examples of the cations having a valency or higher include calcium ions, aluminum ions, magnesium ions, iron ions, manganese ions, cobalt ions, nickel ions, zinc ions, cadmium ions, strontium ions, copper ions, lead ions, and barium ions. Among them, calcium ions are preferred in view of the ability to form a crosslinked structure and economy. The calcium compound that can supply calcium ions is not particularly limited, and examples thereof include calcium chloride, calcium lactate, calcium sulfate, calcium citrate, calcium hydrogen phosphate, and calcium carbonate. Preferred among these is calcium chloride. In addition, when adding a water-insoluble calcium compound such as calcium carbonate as a calcium compound, in order to promote ionization of calcium,
An inorganic acid such as sulfuric acid or hydrochloric acid, or an organic acid such as adipic acid, citric acid, lactic acid or glucono delta lactone may be used in combination to promote the formation of a crosslinked structure. Further, when a divalent or higher valent cation is contaminated in a reaction product obtained by combining the component (A) and the component (B), for example, a water-soluble polymer or a diluting water for diluting a mixture of the two. In addition, when a calcium compound that is hardly soluble in water such as calcium sulfate is added as a calcium compound, sodium hexametaphosphate or tetrapyrophosphate is used to control the rate of formation of a crosslinked structure and suppress local crosslinking reaction. A sequestering agent such as sodium, trisodium citrate and ethylenediaminetetraacetic acid may be used in combination.

The concentration of the diluent of the water-soluble polymer and the addition ratio of the calcium compound to the water-soluble polymer are determined based on the paper strength such as interlayer strength improver and burst strength when the calcium compound is added to the water-soluble polymer. It can be determined in consideration of the performance and workability as an improver, and the following ranges are preferable. The concentration of the diluent of the water-soluble polymer is 0.01 to 8% by weight, preferably 0.1 to 5% by weight.
It is. The addition rate of the calcium compound to the water-soluble polymer is 0.0005 to 5% by weight, preferably 0.001 to 5% by weight, based on the water-soluble polymer diluent as calcium ions.
3% by weight. In addition, the above-mentioned ion may be contained in the wet paper which is sprayed with an interlayer strength improver described later, and in this case, calcium ion is also preferable. For example, papermaking may be performed in the presence of calcium carbonate or other chemicals. In the case of the mixture of the component (A) and the component (B), the concentration of the diluent, the addition rate of the calcium compound, and other factors are the same as those of the water-soluble polymer.

The reaction product obtained by combining the component (A) and the component (B), for example, a water-soluble polymer has various uses and is also used as an internally added paper strength improver. When used as a strength improver, the properties of this water-soluble polymer can be exhibited well. The interlayer strength improver in the present invention may be the polymerization reaction product liquid as it is, or may be prepared by adding other additive components to the water-soluble polymer isolated from the polymerization reaction product solution as needed. The water-soluble polymer isolated from the polymerization reaction product solution may be dissolved in water so as to have a predetermined concentration together with other components added as necessary,
It may be prepared. In a preferred embodiment, a polymerization reaction product liquid obtained by the polymerization reaction is used as it is as a paper modifier such as an interlayer strength improver or an internally added paper strength improver. The concentration of the water-soluble polymer in the interlayer strength improver is usually from 5 to 40% by weight, preferably from 10 to
３０30% by weight. The viscosity of the interlayer strength improver is
It is usually from 100 to 100,000 mPa · s (measured at 25 ° C. by a Brookfield rotational viscometer), and preferably from 500 to 20,000 mPa · s. The interlayer strength improver in the present invention, when producing a multi-layer papermaking, the diluent is applied to the surface of the wet paper immediately after paper making by spraying or the like, and then combined with another wet paper immediately after paper making. Used for The combined wet paper is dewatered and dried to produce a multilayer paper. In addition, when used by coating with a spray or the like, it is usually sprayed on the surface of a wet paper, but it is also effective to apply on a dry paper surface by spraying and mixing. still,
Other papermaking additives such as starch, modified starch, casein, CMC, which have been conventionally used as an interlayer strength improver,
In order to develop the physical properties required for each paper type, they may be used in combination with the interlayer strength improver according to the present invention, if necessary. Further, the interlayer strength improver of the present invention can be used by directly adding it to a pulp slurry as an internal paper strength improver in a paper or paperboard manufacturing process for the purpose of improving paper strength. The diluent concentration of the interlayer strength improver is 0.01 to 8% by weight in solid content, preferably 0.1 to 8% by weight.
1 to 5% by weight. In addition, the viscosity when the diluted interlayer strength improver is used is about 1 to 50 mPa · s, and the pH is 2.5 to 8.0. In addition, when the interlayer strength improver of the present invention is used by being mixed into a pulp slurry as an internal paper strength improver such as burst strength, the amount used is usually 0.01 to 10% in terms of solids relative to pulp solids. 8% by weight, preferably 0.05 to 4% by weight. Even in the case of a mixture of the component (A) and the component (B), a method of using the mixture as a concentration, a diluent concentration, a viscosity, and the like, and an interlayer strength improver or an internally added paper strength improver. Is as described above.

In producing the multi-layer paper, there is no particular limitation on the paper of each single layer, but the sulfuric acid band may or may not be used at all depending on the type of paper. Further, the paper may be a paper whose pH is appropriately adjusted by adding an alkaline substance or an acidic substance. For example, when producing paper or paperboard in the acidic to neutral or alkaline range, bleaching such as kraft pulp or sulfite pulp or unbleached chemical pulp, groundwood pulp, mechanical pulp or thermomechanical pulp, etc. Unbleached high yield pulp, newspaper waste,
Any used paper pulp such as used magazine paper, used corrugated paper, or used deinked paper can be used. Further, as the pulp raw material, a mixture of the pulp raw material and asbestos, polyamide, polyester, polyolefin, or the like can also be used. Fillers, dyes, rosin sizing agents for acidic papermaking, rosin sizing agents for neutral papermaking, ketene dimer sizing agents (alkyl ketene dimer sizing agent, alkenyl ketene dimer sizing agent, etc.), alkenyl succinic anhydride Acidic and neutral to alkaline papermaking sizing agents such as sizing agents, specially modified rosin sizing agents, etc., dry paper strength improvers, wet paper strength improvers, retention improvers, drainage improvers, defoamers, etc. Other papermaking additives,
In order to develop the physical properties required for each paper type, they may be used in combination with the interlayer strength improver according to the present invention, if necessary. Examples of the filler include clay, talc, titanium oxide, heavy or light calcium carbonate, and these may be used alone or in combination of two or more. Preferred as filler is heavy or light calcium carbonate. The same applies to the case where a single-layer internally added paper or an internally added paper wet paper is used as a multilayer paper.

[0026]

BEST MODE FOR CARRYING OUT THE INVENTION In the presence of alginic acids mainly containing an alkali metal salt of alginic acid, a quaternary compound of 89.99 to 98 mol% of acrylamide as the component (b1) and dimethylaminoethyl acrylate as the component (b2) 1 to
7 mol%, 0.01 to 0.05 mol% of methylenebisacrylamide as the component (b3), 0.1 to 3 mol% of an alkali metal salt of methallylsulfonic acid and / or an unsaturated dicarboxylic acid as the component (b4) ( b1 to b4), 90 to 98 mol% of acrylamide as the component (b1), 1 to 7 mol% of a quaternized dimethylaminoethyl acrylate as the component (b2), and alkali of methallylsulfonic acid as the component (b4). The metal salt and / or unsaturated dicarboxylic acid is used in an amount of 0.1 to 3 mol% (using b1, b2 and b4) in a total weight of each monomer and a weight ratio of alginic acid of 85.
/ 15 to 99.5 / 0.5, and the weight ratio of alginic acid and acrylamide polymer is 85/15 to
Reaction products of alginic acids and polyacrylamide-based polymers selected from 99.5 / 0.5 (alginate-grafted polyacrylamide-based polymers (integrated products), etc.)
To produce a paper modifier comprising a water-soluble polymer aqueous solution containing In addition, (b) in the absence of the alginates
The acrylamide-based polymer obtained by the polymerization of 1-b4) and the alginic acids are 85/15 to 9 in terms of solids weight ratio.
A paper modifier comprising an aqueous mixture of 9.5 / 0.5 is prepared. These paper modifiers are used as interlayer strength improvers, and as interlayer strength improvers to which alkaline earth metal ions are added, using ordinary pulp and waste paper pulp to obtain acidic, Wet papers obtained from the respective papermaking systems of neutral to alkaline and clay-based filler-added systems are combined to obtain a multilayer paper. The multilayer paper thus obtained improves the paper strength such as the interlaminar strength and the specific burst strength due to the presence of alginic acids, unlike the case where various starches are similarly present without the use of alginic acids. be able to. In addition, even if the paper modifier is added internally and used as a paper strength improver, paper strength such as burst strength and internal bond strength can be improved.

[0027]

EXAMPLES Examples of the present invention will be described below, but the present invention is not limited by these examples. In addition,% is based on weight. Synthesis Example 1 (polymerization of b1 to b4 monomers in the presence of alginic acids) In a 1-liter four-necked flask equipped with a stirrer, a thermometer, a reflux condenser, and a nitrogen gas inlet tube, 699.89 g of water was added.
221.79 g of a 50% aqueous acrylamide solution (94.7
95 mol%), 29.15 g of an aqueous solution of 76% acryloyloxyethyldimethylbenzylammonium chloride
(4.99 mol%) 6.33 g (0.025 mol%) of a 1% aqueous solution of N, N 'methylenebisacrylamide, 9.87 g (0.15 g of a 5% aqueous solution of sodium methallylsulfonate)
9 mol%) and adjusted to pH 4.0 with a 30% aqueous sodium hydroxide solution, and then 14.79 g of sodium alginate (Kimitsu-Algin ULV-20: a low-viscosity product manufactured by Kimitsu Chemical Industry Co., Ltd .; the same applies hereinafter)) was charged. Then, 3.75 g of a 5% ammonium persulfate aqueous solution was added, the temperature was raised to 80 ° C. under nitrogen gas introduction, and the reaction was carried out for 2 hours.
An aqueous solution of sodium alginate and polyacrylamide copolymer having a viscosity of 5.8%, a viscosity of 8,850 mPa · s (25 ° C., using a Brookfield rotational viscometer) and a pH of 4.4 was obtained. This was designated as interlayer strength improver A.
The total weight of each monomer and the weight ratio of sodium alginate are 90/10.

Synthesis Example 2 (b1-b in the presence of alginic acids)
Polymerization of 4 Monomers) In a 1-liter four-necked flask equipped with a stirrer, a thermometer, a reflux condenser, and a nitrogen gas inlet tube, 695.13 g of water was added.
221.41 g of a 50% aqueous acrylamide solution (94.7
00 mol%), 76% acryloyloxyethyldimethylbenzylammonium chloride aqueous solution 29.1 g
(4.986 mol%), 1% N, N 'methylene bisacrylamide aqueous solution 6.32 g (0.025 mol%), 5%
15.04 g of sodium methallyl sulfonate aqueous solution
(0.289 mol%), and after adjusting the pH to 4.0 with a 30% aqueous sodium hydroxide solution, 14.76 g of sodium alginate (Argitex AG-LL: a crude product of Kimitsu Chemical Industry Co., Ltd .; the same applies hereinafter) was charged. It is. Then, 3.74 g of a 5% ammonium persulfate aqueous solution was added, the temperature was raised to 80 ° C. under nitrogen gas introduction, and the reaction was carried out for 2 hours. The solid content was 15.5%, and the viscosity (25 ° C., using a Brookfield rotary viscometer) An aqueous solution of sodium alginate and a polyacrylamide copolymer having a pH of 300 mPa · s and a pH of 4.5 was obtained. This was designated as interlayer strength improver B.
The total weight of each monomer and the weight ratio of sodium alginate are 90/10.

Synthesis Example 3 (b1-b in the presence of alginic acids)
Polymerization of 4 monomers) 691.31 g of water was placed in a 1-liter four-necked flask equipped with a stirrer, a thermometer, a reflux condenser, and a nitrogen gas inlet tube.
233.88 g of a 50% acrylamide aqueous solution (94.7
57% by mole), 76% aqueous solution of acryloyloxyethyldimethylbenzylammonium chloride 30.74 g
(4.989 mol%) 1% N, N 'methylenebisacrylamide aqueous solution 6.68 g (0.025 mol%), 5%
12.6 g of an aqueous solution of sodium methallyl sulfonate (0.
229 mol%) and adjusted to pH 4.0 with a 30% aqueous sodium hydroxide solution, and then 7.39 g of sodium alginate (Argitex AG-LL) was charged. Next, 3.95 g of a 5% ammonium persulfate aqueous solution was added, the temperature was raised to 80 ° C. under nitrogen gas introduction, and the reaction was carried out for 2 hours. 700 mPa · s, pH4.
Thus, an aqueous solution of sodium alginate and a polyacrylamide copolymer was obtained. This is called an interlayer strength improver
C. The total weight of the monomers and the weight ratio of sodium algin were 95/5.

Synthesis Example 4 (b1-b in the presence of alginic acids)
Polymerization of 4 Monomers) In a 1-liter four-necked flask equipped with a stirrer, a thermometer, a reflux condenser, and a nitrogen gas inlet tube, 687.55 g of water was added.
243.81 g (94.7) of a 50% aqueous acrylamide solution
86 mol%), 32.04 g of 76% acryloyloxyethyldimethylbenzylammonium chloride aqueous solution
(4.989 mol%) 1% N, N 'methylenebisacrylamide aqueous solution 6.96 g (0.025 mol%), 5%
11.42 g of aqueous solution of sodium methallylsulfonate
(0.2 mol%), the pH was adjusted to 4.0 with a 30% aqueous sodium hydroxide solution, and then 1.48 g of sodium alginate (Argitex AG-LL) was charged. Next, 4.12 g of a 5% aqueous ammonium persulfate solution was added, the temperature was raised to 80 ° C. under nitrogen gas introduction, and the reaction was carried out for 2 hours. The solid content was 15.6%, and the viscosity was 25 ° C. (using a Brookfield rotational viscometer). 950 mPa · s, pH3.
Thus, an aqueous solution of sodium alginate of No. 9 and a polyacrylamide copolymer was obtained. This is called an interlayer strength improver
D The total weight of each monomer and the weight ratio of alginic acids are 99/1.

Synthesis Example 5 (b1 to b1 in the absence of alginic acids)
b4 Polymerization of Monomer) In a 1-liter four-necked flask equipped with a stirrer, a thermometer, a reflux condenser, and a nitrogen gas inlet tube, 686.24 g of water was added.
246.25 g of a 50% aqueous acrylamide solution (94.7
86 mol%), 32.36 g of 76% acryloyloxyethyldimethylbenzylammonium chloride aqueous solution
(4.989 mol%) 1% N, N 'methylenebisacrylamide aqueous solution 7.03 g (0.025 mol%), 5%
Sodium methallyl sulfonate aqueous solution 11.53 g
(0.2 mol%) and adjusted to pH 4.0 with a 30% aqueous sodium hydroxide solution. Next, 4.16 g of a 5% ammonium persulfate aqueous solution was added, the temperature was raised to 80 ° C. under nitrogen gas introduction, and the reaction was carried out for 2 hours to obtain a solid content of 15.8.
%, An aqueous solution of a cationic polyacrylamide copolymer having a viscosity of 8,600 mPa · s (25 ° C., using a Brookfield rotational viscometer) and a pH of 3.5.

Synthesis Example 6 (Aqueous solution of mixture of alginic acid and acrylamide polymer) A solution obtained by diluting the aqueous solution of the cationic polyacrylamide copolymer obtained in Synthesis Example 5 with water to a polymer concentration of 1.5%. Weight ratio of cationic polyacrylamide copolymer and sodium alginate obtained by mixing a water diluent having a concentration of 1.5% sodium alginate (Chimitsuargin ULV-20) at a solid content of 9: 1 The aqueous solution of the 90/10 mixture was used as interlayer strength improver E.

Synthesis Example 7 (b1-b in the presence of alginic acids)
Polymerization of 4 Monomers) In a 1-liter four-necked flask equipped with a stirrer, a thermometer, a reflux condenser, and a nitrogen gas inlet tube, 690.17 g of water was added.
238.91 g of a 50% acrylamide aqueous solution (94.7
85 mol%), 76% acryloyloxyethyldimethylbenzylammonium chloride aqueous solution 31.4 g
(4.99 mol%), 6.82 g (0.025 mol%) of a 1% aqueous solution of N, N 'methylenebisacrylamide, and 11.19 g of a 5% aqueous solution of sodium methallylsulfonate (0.19 mol%).
2 mol%) and adjusted to pH 4.0 with a 30% aqueous sodium hydroxide solution, and then 4.43 g of sodium alginate (Argitex AG-LL) was charged. Then 5%
4.04 g of an aqueous solution of ammonium persulfate was added, the temperature was raised to 80 ° C. under the introduction of nitrogen gas, and the reaction was carried out for 2 hours. An aqueous solution of sodium alginate and a polyacrylamide copolymer having a pH of 4.3 was obtained. This was designated as interlayer strength improver F and internally added paper strength improver f. The total weight of the monomers and the weight ratio of alginic acids were 97/3.

Synthesis Example 8 (b1-b in the presence of alginic acids)
Polymerization of 4 Monomers) In a 1-liter four-necked flask equipped with a stirrer, a thermometer, a reflux condenser, and a nitrogen gas inlet tube, 699.58 g of water was added.
230.62 g of a 50% aqueous acrylamide solution (92.8
08 mol%), 30.96 g of 76% aqueous acryloyloxyethyldimethylbenzylammonium chloride solution
(4.99 mol%), 4.54 g of itaconic acid (1.99 mol%).
7 mol%), 6.72 g (0.025 mol%) of a 1% aqueous solution of N, N 'methylenebisacrylamide, 9.93 g (0.18 mol%) of a 5% aqueous solution of sodium methallylsulfonate, and 30% water PH with aqueous sodium oxide solution
After adjusting to 4.0, 4.44 g of sodium alginate (Argitex AG-LL) was charged. Next, 3.98 g of a 5% aqueous ammonium persulfate solution was added, the temperature was raised to 80 ° C. under nitrogen gas introduction, and the reaction was carried out for 2 hours.
An aqueous solution of sodium alginate and a polyacrylamide copolymer having a 5.4% viscosity (25 ° C., using a Brookfield rotational viscometer) of 7,850 mPa · s and a pH of 4.0 was obtained. This was designated as interlayer strength improver G and internally added paper strength improver g. The total weight of the monomers and the weight ratio of sodium alginate were 97/3.

Synthesis Example 9 (b1, b
2. Polymerization of b4 monomer) 707.9 g of water was placed in a 1-liter four-necked flask equipped with a stirrer, thermometer, reflux condenser, and nitrogen gas inlet tube.
222.07 g of a 0% acrylamide aqueous solution (94.85
7 mol%), 29.18 g of a 76% aqueous solution of acryloyloxyethyldimethylbenzylammonium chloride
(4.993 mol%), 7.8 g (0.15 mol%) of a 5% aqueous solution of sodium methallylsulfonate was charged, and 30
After adjusting the pH to 4.0 with an aqueous sodium hydroxide solution,
13. Sodium alginate (Argitex AG-LL)
8 g were charged. Then, 3.75 g of a 5% ammonium persulfate aqueous solution was added, the temperature was raised to 80 ° C. under nitrogen gas introduction, and the reaction was carried out for 2 hours.
℃, Brookfield rotational viscometer) 8,700m
An aqueous solution of sodium alginate and a polyacrylamide copolymer having a Pa · s of pH 4.3 was obtained. This was designated as interlayer strength improver H. The total weight of each monomer and the weight ratio of sodium alginate are 90/10.

Synthesis Example 10 (b1 to b1 in the absence of alginic acid)
b4 Polymerization of Monomer) In a 1-liter four-necked flask equipped with a stirrer, a thermometer, a reflux condenser, and a nitrogen gas inlet tube, 692.79 g of water was added.
237.79 g of a 50% aqueous acrylamide solution (92.8
22% by mol), 31.92 g of 76% aqueous solution of acryloyloxyethyldimethylbenzylammonium chloride
(4.991 mol%), 4.68 g of itaconic acid (1.9
97 mol%), 6.93 g (0.025 mol%) of a 1% aqueous solution of N, N 'methylenebisacrylamide, 9.39 g (0.165 mol%) of a 5% aqueous solution of sodium methallylsulfonate, and 30% water PH with aqueous sodium oxide
It was adjusted to 4.0. Next, 4.10 g of a 5% aqueous ammonium persulfate solution was added, the temperature was raised to 80 ° C. under nitrogen gas introduction, and the reaction was carried out for 2 hours. The solid content was 15.2% and the viscosity (2
5 ° C, using Brookfield rotational viscometer) 7,500
An aqueous solution of an amphoteric polyacrylamide copolymer having an mPa · s and a pH of 4.1 was obtained.

Synthesis Example 11 (Aqueous solution of mixture of alginic acid and polymer of Synthesis Example 10) Diluent obtained by diluting the aqueous solution of amphoteric polyacrylamide copolymer obtained in Synthesis Example 10 with water to a polymer concentration of 1.5% And sodium alginate (Algitex AG
-LL) with a 1.5% water diluent at a weight ratio of 97/3, and the resulting cationic polyacrylamide-based copolymer polymer and an aqueous solution of sodium alginate were added to interlayer strength improver I and internally. This was designated as paper strength improver i.

Synthesis Example 12 (Drop polymerization in the presence of alginic acids) In a 1-liter four-necked flask equipped with a stirrer, thermometer, reflux condenser, and nitrogen gas inlet tube, 651.56 g of water was added.
152.91 g of a 50% acrylamide aqueous solution (61.9
12 mol%), 4.51 g (1.996 mol%) of itaconic acid, 4.55 g (0.017 mol%) of 1% aqueous solution of N, N 'methylenebisacrylamide, 4.11 g of 5% aqueous solution of sodium methallylsulfonate (0.075 mol%)
And pH 3.5 with a 30% aqueous sodium hydroxide solution.
After adjustment to sodium alginate (Algitex
AG-LL) 4.43 g was charged. Next, after the temperature was raised to 65 ° C. under the introduction of nitrogen gas, 1.98 g of a 5% ammonium persulfate aqueous solution was added to start the reaction. continue,
When the temperature reached 85 ° C., water 29.4 which had been separately charged was used.
0 g, 50% aqueous acrylamide aqueous solution 76.46 g (3
0.958 mol%), 76% aqueous acryloyloxyethyldimethylbenzylammonium chloride solution30.
79 g (4.994 mol%), 1% N 2, N ′ methylene bisacrylamide aqueous solution 2.14 g (0.008 mol%), 5% sodium methallyl sulfonate aqueous solution 2.1
An aqueous monomer solution consisting of 9 g (0.040 mol%) was dropped by a dropping funnel over 30 minutes. After the completion of the dropwise addition, the mixture was reacted at a reaction temperature of 90 ° C. for 2 hours.
A copolymer aqueous solution having a pH of 4,000 mPa · s and a pH of 4.4 was obtained. This is used as interlayer strength improver J and internally added paper strength improver j.
And The total weight of each monomer and the weight ratio of alginic acids were 97/3.

Synthesis Example 13 (Drop polymerization in the presence of alginic acids) In a 1-liter four-necked flask equipped with a stirrer, a thermometer, a reflux condenser, and a nitrogen gas inlet tube, 647.6 g of water was added.
152.69 g of a 0% acrylamide aqueous solution (61.86
30 mol%), 76% aqueous acryloyloxyethyldimethylbenzylammonium chloride solution
(4.989 mol%) 1% N, N 'methylenebisacrylamide aqueous solution 4.54 g (0.017 mol%), 5%
7.12 g of an aqueous solution of sodium methallyl sulfonate (0.1 g)
130 mol%) and adjusted to pH 3.5 with a 30% aqueous sodium hydroxide solution, and then 4.43 g of sodium alginate (Argitex AG-LL) was charged. Next, after the temperature was raised to 65 ° C. under nitrogen gas introduction, 2.04 g of a 5% aqueous solution of ammonium persulfate was added to start the reaction. Subsequently, when the temperature reached 85 ° C., 29.40 g of separately charged water, 50% aqueous acrylamide solution 7
6.34 g (30.930 mol%), itaconic acid 4.5
1 g (1.997 mol%), 2.14 g (0.008 mol%) of a 1% aqueous solution of N, N 'methylenebisacrylamide,
3.56 g of 5% sodium methallylsulfonate aqueous solution
(0.065 mol%) was dropped by a dropping funnel over 30 minutes. After the completion of the dropwise addition, the mixture was reacted at a reaction temperature of 90 ° C. for 2 hours, and had a solid content of 15.2% and a viscosity (25 ° C., using a Brookfield rotational viscometer).
An aqueous copolymer solution having a viscosity of 50 mPa · s and a pH of 4.2 was obtained.
These were designated as interlayer strength improver K and internally added paper strength improver k. The total weight of each monomer and the weight ratio of alginic acids were 97/3.

Synthesis Example 14 (Drop polymerization in the absence of alginic acid) In a 1-liter four-necked flask equipped with a stirrer, a thermometer, a reflux condenser, and a nitrogen gas inlet tube, 645.05 g of water was added.
164.81 g of a 50% aqueous acrylamide solution (62.8
70 mol%), 3.59 g (1.497 mol%) of itaconic acid, 4.82 g (0.017 mol%) of 1% aqueous solution of N, N 'methylenebisacrylamide, 6.98 g of 5% aqueous solution of sodium methallylsulfonate (0.120 mol%)
And pH 3.5 with a 30% aqueous sodium hydroxide solution.
After adjusting to 5% aqueous solution of ammonium persulfate 2.01
g was added to start the reaction. Subsequently, when the temperature reached 85 ° C., 24.94 g of separately charged water, 82.41 g (31.437 mol%) of a 50% aqueous acrylamide solution, and 26.12 g of a 76% acryloyloxyethyldimethylbenzylammonium chloride aqueous solution ( 3.9
An aqueous monomer solution consisting of 2.27 g (0.008 mol%) of a 1% aqueous solution of N, N ′ methylenebisacrylamide in water and 3.49 g (0.060 mol%) of a 5% aqueous solution of sodium methallylsulfonate was added dropwise. 30 by funnel
Dropped over minutes. After the completion of the dropwise addition, the mixture was reacted at a reaction temperature of 90 ° C. for 2 hours. The solid content was 15.4%, the viscosity (25 ° C., using a Brookfield rotational viscometer) 5,000 mPa · s,
An aqueous solution of an acrylamide-based polymer copolymer having a pH of 4.1 was obtained.

Synthesis Example 15 (Aqueous Solution of Mixture of Alginic Acids and Acrylamide Polymer) An aqueous solution of the acrylamide polymer copolymer aqueous solution obtained in Synthesis Example 14 was diluted with water to a concentration of 1.5%, and sodium alginate ( Argitex AG-LL)
% Of a water diluent to obtain a solid content of 97: 3, and an aqueous solution of a mixture of an acrylamide polymer and sodium alginate was used as an interlayer strength improver L and an internally added paper strength improver l.

Synthesis Example 16 (Aqueous solution of mixture of alginic acid and acrylamide polymer) Aqueous solution of acrylamide polymer copolymer obtained in Synthesis Example 14 was diluted with water to a polymer concentration of 1.5%, and sodium alginate was used. An aqueous solution of a mixture of acrylamide-based polymer and sodium alginate obtained by mixing a water diluent having a concentration of (Argitex AG-LL) of 2% with a solid content of 90:10, and internally adding a paper strength improver m.

Synthesis Example 17 (Polymerization of b1 to b4 monomers in the presence of starch (for comparative example)) .92 g,
230.62 g of a 50% aqueous acrylamide solution (92.8
08 mol%), 30.96 g of 76% aqueous acryloyloxyethyldimethylbenzylammonium chloride solution
(4.99 mol%), 4.54 g of itaconic acid (1.99 mol%).
7% by mol), 6.72 g (0.025 mol%) of a 1% aqueous solution of N, N 'methylenebisacrylamide, and 9.93 g (0.18 mol%) of a 5% aqueous solution of sodium methallylsulfonate were added. PH with aqueous sodium oxide solution
After adjusting to 4.0, urea phosphate starch 4.44.
g. Next, 3.98 g of a 5% ammonium persulfate aqueous solution was added, the temperature was raised to 80 ° C. under nitrogen gas introduction, and the reaction was carried out for 2 hours. The solid content was 15.5%, and the viscosity was 25%.
℃, Brookfield rotational viscometer) 5,900m
An aqueous solution of a copolymer having a Pa · s and pH of 4.0 was obtained. This was used as an aqueous solution of a polymerized polyacrylamide polymer in the presence of urea phosphate starch. The total weight of each monomer and the weight ratio of starch were 97/3.

Synthesis Example 18 (Polymerization of monomers b1 to b4 in the presence of starch (for comparative example)) 237.5 g of water and 17.5 g of urea phosphate starch were placed in the 1 liter flask and heated to 90 ° C. with stirring. Next, 287 g (97.7 mol%) of a 50% aqueous acrylamide solution and 2.5 parts of itaconic acid were added to the dropping funnel for monomer.
g (0.93 mol%), N, N-dimethylaminoethyl methacrylate 4.0 g (1.23 mol%), N, N-
0.25 g (0.12 mol%) of dimethylacrylamide
And 133.5 g of water, and adjusted to pH 4 with sulfuric acid.
Was adjusted. Further, 0.7 g of ammonium persulfate and 50 g of water were charged as a polymerization initiator in the dropping funnel for the catalyst. After removing all the oxygen in the reaction system through nitrogen gas, the catalyst was continuously added dropwise for 200 minutes, while the monomer mixture was added dropwise for 120 minutes.
The polymerization was carried out under reflux, and the solid content was 15.6%, and the viscosity (25%).
° C, Brookfield rotational viscometer) 5,700m
A polyacrylamide-based copolymer polymer aqueous solution b in the presence of urea phosphate starch having a Pa · s and pH of 4.2 was obtained. The total weight of the monomers and the weight ratio of the urea phosphate starch were 89.6 / 10.4.

Example 1 (Use of interlayer strength improvers A to E) BKP (L / N = 9/1) adjusted to 414 (Canadian Standard Freeness, hereinafter abbreviated as CSF) To a 2.4% pulp slurry, 0.5% of a sulfuric acid band was added to the pulp, and 0.2% of an amphoteric polyacrylamide-based paper strength enhancer (DS457 manufactured by PMC Japan) was added to the pulp. After stirring, the pulp slurry was diluted with water so pH6.0 at a concentration of 0.25%, and paper in Noble and Wood sheet made machine, basis weight 100 g / m ^2, moisture content 91.2% 2 wet paper
Were manufactured. A coating amount of 0.66 g / m ² of a 0.16% diluent of each of the interlayer strength improvers A to E obtained in Synthesis Examples 1 to 5 was applied to one surface of one wet paper. After spray coating as described above, another wet paper was placed on the coated surface, pressed, and dried with a drum dryer to obtain a laminated paper. The obtained laminated paper is subjected to 20 ° C., 65% R
After conditioning for 24 hours under the condition of H (relative humidity), each sample was subjected to each measurement shown in Table 1. The addition rate of the above chemicals is the weight ratio of solid content to the absolute dry weight of pulp. Table 1 shows the measurement results.
Shown in The interlayer strength was shown by T-shaped peel strength.

Comparative Example 1 In Example 1, a 0.16% ungelatinized slurry of starch for interlayer spraying (Histard PSS-9 manufactured by Sanwa Starch Co., Ltd.) was used instead of the interlayer strength paper strength agents A to E. A laminated paper was obtained in the same manner except for the fact that the paper was not used. Table 1 shows the results of the measurement in the same manner as in Example 1.

Comparative Example 2 In Example 1, except that the 0.16% diluted solution of the cationic polyacrylamide-based polymer obtained in Synthesis Example 5 was used instead of using the interlayer strength paper strength agents A to E. Similarly, a laminated paper was obtained. This is also Example 1
Table 1 shows the measurement results in the same manner as in Example 1.

Comparative Example 3 A laminated paper was obtained in the same manner as in Example 1, except that water was used instead of the interlayer strength papers A to E. Table 1 shows the results of the measurement in the same manner as in Example 1.

[0049]

[Table 1]

Example 2 (interlayer strength improvers FG, J, L
Use of BKP (L / N = 9/1) with C.I. S. F. = 2.4% pulp slurry adjusted to 407 = 0.25
% And diluted with water having a pH of 7.0 to make a sheet with a sheet machine made by Noble & Wood.
^Two wet papers having m ² and a water content of 91.5% were produced. Interlaminar strength improver F obtained in Synthesis Examples 7 to 8 on one surface of one wet paper
To G, J, and L were spray-coated with a 0.16% solids solution so that the coating amount was 0.6 g / m ² , and the other wet paper web was coated on the coated surface. After stacking, pressing and drying with a drum dryer, a laminated paper was obtained.
The obtained laminated paper was conditioned for 24 hours under conditions of 20 ° C. and 65% RH, and then subjected to each measurement shown in Table 2. The addition rate of the above chemicals is the weight ratio of solid content to the absolute dry weight of pulp. Table 2 shows the measurement results.

Comparative Example 4 Instead of using the interlayer strength paper strength agents FG, J and L in Example 2, 0.16% unpaste of starch for interlayer spraying (Histard PSS-9 manufactured by Sanwa Starch Co., Ltd.) was used. A laminated paper was obtained in the same manner except for using the activated slurry. Table 2 shows the results of the measurement in the same manner as in Example 2.

Comparative Example 5 A laminated paper was obtained in the same manner as in Example 2, except that water was used instead of the interlayer strength paper strength agents FG, J, and L. Table 2 shows the results of the measurement in the same manner as in Example 2.

Example 3 (Modification of Example 2 (Use of Sulfuric Acid Band)) In Example 2, instead of using interlayer strength paper strength agents FG, J and L, interlayer strength paper strength agents FG and K was used to obtain a laminated paper in the same manner except that a sulfuric acid band was added to pulp at 1.0% and the pulp slurry was diluted with water at pH 6.0 to a concentration of 0.25%. Was. Table 2 shows the results of the measurement in the same manner as in Example 2.

Comparative Example 6 Instead of using interlayer strength paper strength agents FG and K in Example 3, 0.16% ungelatinized slurry of starch for interlayer spraying (Histard PSS-9 manufactured by Sanwa Starch Co., Ltd.) A laminated paper was obtained in the same manner except for using. Table 2 shows the results of the measurement in the same manner as in Example 2.

Comparative Example 7 A laminated paper was obtained in the same manner as in Example 3, except that water was used instead of the interlayer strength paper strength agents FG and K. Table 2 shows the results of the measurement in the same manner as in Example 2.

Example 4 (Modification of Example 3 (Increased Use of Sulfuric Acid Band)) In Example 2, instead of using interlayer strength paper strength agents FG, J and L, interlayer strength paper strength agent F To G, a sulfuric acid band was added to the pulp at 3.0%, and the pulp slurry was diluted with water at a pH of 4.5 to a concentration of 0.25% in the same manner as above. Obtained. Table 2 shows the results of the measurement in the same manner as in Example 2.

Comparative Example 8 In Example 4, a 0.16% ungelatinized slurry of starch for interlayer spraying (Histard PSS-9 manufactured by Sanwa Starch Co., Ltd.) was used instead of using interlayer strength paper strength agents FG. A laminated paper was obtained in the same manner except for the fact that the paper was not used. Table 2 shows the results of the measurement in the same manner as in Example 2.

Comparative Example 9 A laminated paper was obtained in the same manner as in Example 4, except that water was used instead of the interlayer strength paper strength agents FG. Table 2 shows the results of the measurement in the same manner as in Example 2.

[0059]

[Table 2]

Example 5 (Example of application to papermaking using waste paper pulp) S. F. Pulp slurry having a concentration of 2.4% adjusted to = 389 was diluted with water having a pH of 7.0 so as to have a concentration of 0.25%, and paper was made using a Noble & Wood sheet machine to obtain a basis weight of 100 g / m ^2. And two wet papers having a moisture content of 90.3% were produced. On one surface of one of the wet paper webs, a 0.16% dilute solution of each of the interlaminar strength improvers FG obtained in Synthesis Examples 7 to 8 was applied at a coating amount of 0.6.
g / m ² , and another wet paper was placed on the coated surface, pressed, and dried with a drum dryer to obtain a laminated paper. The obtained laminated paper was conditioned at 20 ° C. and 65% RH for 24 hours, and then subjected to each measurement shown in Table 3. The addition rate of the above chemicals is the weight ratio of solid content to the absolute dry weight of pulp. Table 3 shows the measurement results.

Comparative Example 10 Instead of using the interlayer strength paper strengthening agents FG in Example 5, a 0.16% ungelatinized slurry of starch for interlayer spraying (Histard PSS-9 manufactured by Sanwa Starch Co., Ltd.) was used. A laminated paper was obtained in the same manner except for the fact that the paper was not used. Table 3 shows the results of the measurement in the same manner as in Example 5.

Comparative Example 11 A laminated paper was obtained in the same manner as in Example 5 except that water was used instead of the interlayer strength paper strength agents FG. Table 3 shows the results of the measurement in the same manner as in Example 5.

Example 6 (Example using acid papermaking system (use of sulfuric acid band) of waste paper pulp)
%, And the pulp slurry was diluted with water having a pH of 6.0 to obtain a concentration of 0.25% to obtain a laminated paper. Table 3 shows the results of the measurement in the same manner as in Example 5.

Comparative Example 12 In Example 6, a 0.16% ungelatinized slurry of starch for interlayer spraying (Histard PSS-9 manufactured by Sanwa Starch Co., Ltd.) was used instead of using interlayer strength paper strength agents FG. A laminated paper was obtained in the same manner except for the fact that the paper was not used. Table 3 shows the results of the measurement in the same manner as in Example 5.

Comparative Example 13 A laminated paper was obtained in the same manner as in Example 6, except that water was used instead of the interlayer strength paper strength agents FG. Table 3 shows the results of the measurement in the same manner as in Example 5.

Example 7 (Increased amount of sulfate band in Example 6) In Example 5, the sulfate band was added to pulp at 3.0.
%, And the pulp slurry was diluted with water at pH 4.5 to obtain a concentration of 0.25% to obtain a laminated paper. Table 3 shows the results of the measurement in the same manner as in Example 5.

COMPARATIVE EXAMPLE 14 Instead of using the interlayer strength paper strength agents FG in Example 7, a 0.16% ungelatinized slurry of starch for interlayer spraying (Histard PSS-9 manufactured by Sanwa Starch Co., Ltd.) was used. A laminated paper was obtained in the same manner except for the fact that the paper was not used. Table 3 shows the results of the measurement in the same manner as in Example 5.

Comparative Example 15 A laminated paper was obtained in the same manner as in Example 7, except that water was used instead of the interlayer strength paper strength agents FG. Table 3 shows the results of the measurement in the same manner as in Example 5.

[0069]

[Table 3]

Example 8 (Example of presence or absence of use of b3 monomer) BKP (L / N = 9/1) S. F. To a pulp slurry having a concentration of 2.4% and adjusted to 407, a sulfuric acid band was added to the pulp at 1.0%. After stirring, the pulp slurry was diluted with water so pH6.0 at a concentration of 0.25%, and paper in Noble and Wood sheet made machine, basis weight 100 g / m ^2, moisture content 90.5% Were produced. On one surface of one wet paper, a 0.16% solids dilution of each of the interlayer strength improvers B (using b3 monomer) and H (using no b3 monomer) obtained in Synthesis Examples 2 and 9 was used. After spray coating so that the coating amount was 0.6 g / m ² , another wet paper was placed on the coated surface, pressed, and dried with a drum dryer to obtain a laminated paper. The obtained laminated paper is subjected to 20 ° C., 65%
After humidifying for 24 hours under the condition of RH, each sample was subjected to each measurement shown in Table 4. The addition rate of the above chemicals is the weight ratio of solid content to the absolute dry weight of pulp. Table 4 shows the measurement results.

Comparative Example 16 A laminated paper was obtained in the same manner as in Example 8, except that water was used instead of the interlayer strength paper strength agents B and H. Table 4 also shows the results of measurement in the same manner as in Example 8.

Example 9 (Integrated product and mixture when itaconic acid is used in combination with b4 monomer) In Example 8, instead of using interlayer strength paper strength agents B and H, each of interlayer strength paper strength agents G and I was used. A laminated paper was obtained in the same manner except that another 0.16% solids dilution was used. Table 4 also shows the results of measurement in the same manner as in Example 8.

Comparative Example 17 The same procedure as in Example 8 was carried out, except that a 0.16% polymer concentration of the aqueous polyacrylamide polymer solution a in the presence of starch was used instead of using the interlayer strength paper strength agents B and H. To obtain a laminated paper. Table 4 also shows the results of measurement in the same manner as in Example 8.

Comparative Example 18 The procedure of Example 8 was repeated, except that the aqueous solution b of the polymerized polyacrylamide polymer in the presence of starch was replaced by a 0.16% polymer concentration instead of using the interlayer strength paper strength agents B and H. To obtain a laminated paper. Table 4 also shows the results of measurement in the same manner as in Example 8.

Example 10 (Combined Use of Calcium Ions) In Example 8, instead of using the interlayer strength paper strength agents B and H, 1.5% each of the interlayer strength improvers G and I was used.
The solid content of each of the interlayer strength improver G (Ca-added product) and the interlayer strength improver I (Ca-added product) obtained by adding 0.3% of CaCl ₂ to the diluent to the diluent was 0 .16
A laminated paper was obtained in the same manner except that a% dilution was used. Table 4 also shows the results of measurement in the same manner as in Example 8.

[0076]

[Table 4]

Example 11 (Example using paper making by neutral to alkaline paper making system (using calcium carbonate)) BKP (L / N = 9/1) S. F. = 414 in a pulp slurry with a concentration of 2.4% adjusted to 414, light calcium carbonate 10.0% in pulp, sulfate band 0.5% in pulp, amphoteric polyacrylamide paper strength agent (Japan PMC Co., Ltd. DS457) was added at 0.2% to the pulp. After stirring, the pulp slurry was diluted with pH 6.0 water to a concentration of 0.25%,
Paper was made using a Noble and Wood sheet machine to produce two wet papers having a basis weight of 100 g / m ² and a water content of 91.2%. One surface of one wet paper was spray-coated with a 0.16% solids concentration of the interlayer strength improver A so that the coating amount was 0.6 g / m ^2, and the other wet paper was coated on the other surface. The paper was layered, pressed and dried with a drum dryer to obtain a laminated paper. The obtained laminated paper is subjected to 20 ° C., 65% R
After conditioning for 24 hours under the condition of H, the samples were subjected to each measurement shown in Table 5. The ash content of the obtained laminated paper was 5.6%. The addition rate of the above chemicals is the weight ratio of solid content to the absolute dry weight of pulp. Table 5 shows the measurement results.

Comparative Example 19 A laminated paper was obtained in the same manner as in Example 11, except that water was used instead of the interlayer strength paper strength agent A. Table 5 shows the results of the measurement performed in the same manner as in Example 11.

Example 12 (Example of Using Paper Making Using Filler Other Than Calcium Carbonate) Except that 10.0% of kaolin was added to pulp in place of light calcium carbonate in Example 11, A laminated paper was obtained. The ash content of the obtained laminated paper was 5.8%. This is also described in Example 11
Table 5 shows the measurement results in the same manner as in the above.

Comparative Example 20 A laminated paper was obtained in the same manner as in Example 12, except that water was used in place of the interlayer strength paper strength agent A. Table 5 shows the results of the measurement performed in the same manner as in Example 11.

[0081]

[Table 5]

Example 13 (Product stability) The interlayer strength improvers A and G were allowed to stand at 40 ° C. for 3 months, and the presence or absence of a precipitate was visually determined. Table 6 shows the results.

Comparative Example 21 The same measurement results as in Example 13 were carried out except that an aqueous solution of a polyacrylamide-based polymer obtained by polymerization in the presence of starch was used in place of the interlayer strength improvers A and G in Example 13. 6 is shown.

[0084]

[Table 6]

The above measurement was carried out according to the following method. T-shaped peel strength… JAPAN-TAPPI Paper pulp test method No.19
Measured according to -77. Specific burst strength: Measured in accordance with JIS P8112. Ash content: JIS P8 except that the temperature was changed to other than 550 ° C
128. Internal bond strength… JAPAN-TAPPI Paper pulp test method No. 54
It measured according to.

Example 14 (Production of paper to be internally added to pulp slurry) S. F. The sulfuric acid band was added to the pulp slurry having a concentration of 2.4% and adjusted to 357 with a sulfuric acid band of 3.0% and stirred for 1 minute. Thereafter, 1.0% of an internally added paper strength improver f was added to the pulp, and the mixture was further stirred for 1 minute. After stirring, the resulting pulp slurry was adjusted to pH 5
Was diluted to 0.8% with water, and paper was made using a Noble and Wood sheet machine to obtain a wet paper. After the wet paper was pressed, it was dried with a drum dryer to obtain a hand-made paper of 80 g / m ² . After the obtained handmade paper was conditioned for 24 hours at 23 ° C. and 50% RH, the specific burst strength was measured by the above-mentioned method (based on JIS P 8112), and the internal bond strength was determined by the internal bonding strength. It was measured using a bond tester (manufactured by Kumagai Riki Kogyo Co., Ltd.). Table 7 shows the results.

Examples 15 to 19 (Production of paper internally added to pulp slurry) Except that in Example 14, instead of using internally added paper strength improver f, internally added paper strength improvers g to l were used. Hand-made paper was obtained in the same manner. Table 7 shows the results of measurement in the same manner as in Example 14.

Comparative Example 22 Hand-made paper was prepared in the same manner as in Example 14, except that the dilute solution of the amphoteric polyacrylamide polymer obtained in Synthesis Example 10 was used instead of using the internally added paper strength improver f. I got Table 7 shows the measurement results in the same manner as in Example 14.

Comparative Example 23 A handmade paper was obtained in the same manner as in Example 14 except that water was used instead of the internally added paper strength improver f. Table 7 shows the measurement results in the same manner as in Example 14.

[0090]

[Table 7]

From the results (Tables 1 and 2) of Examples 1 and 2 and Comparative Examples accompanying these, from the viewpoint of both the T-peeling strength and the specific burst strength, the interlayer strength improvers A to G are comparative examples. It is remarkably superior to 1 to 5, and the one containing the reaction product of alginic acid and acrylamide polymer is superior to the mixture of acrylamide polymer and alginic acid in comparison of interlayer strength improvers A, B and E. Although the weight ratio of acrylamide-based polymer / alginic acid is preferably 99/1 or more, particularly 97/3 or more,
These are expanded to 99.5 / 0.5 or more and 98, respectively.
/ 2 or more (“99/1 or more” may be “at least 99/1”, and so on). From the results (Table 2) of Examples 3 and 4 and the accompanying comparative examples, when the interlayer strength improvers F and G were used in the papermaking of the acidic papermaking system, both of the above performances were compared with those of the comparative examples. Notably good, and among them, interlayer strength improver G, ie, b4
In addition, it is preferable to use itaconic acid in combination. The fact that G is superior to F becomes even more remarkable when applied to papermaking of a papermaking system (Example 4) in which the number of sulfate bands is increased. From the results (Table 3) of Example 5 and Comparative Examples accompanying them, it was found that when the interlayer strength improvers F and G were used, both of the above performances were remarkably better than those of Comparative Examples. Examples 3 and 4
As in the case of papermaking using ordinary pulp, the interlaminar strength improver G is particularly superior in performance to T-shaped peel strength as compared with F.
Since it can be said that the specific burst strengths are almost the same, G is superior to F as a whole, and it can be said that the effect of using itaconic acid is apparent. Also, from the results of Examples 6 and 7 and the comparative examples accompanying these (Table 3), the paper-strengthening agent F,
When G is used, both of the above performances are superior to the comparative example,
It can be said that the difference in performance between G and F is also widened in a system having a large amount of sulfuric acid bands, and the effect of using itaconic acid is more apparent.
From the results (Table 4) of Example 8 and the comparative examples accompanying them, it can be seen that when the interlayer strength improvers B and H were used, both of the above performances were remarkably better than the comparative examples.
B is superior to H, and it can be seen that both of the above-mentioned properties are superior when a b3 monomer is used, that is, when a polyfunctional vinyl monomer (crosslinked vinyl monomer) is used.

From the results of Example 9 and Comparative Examples accompanying them (Table 4), when the interlaminar strength improvers G and I were used, both of the above performances were remarkably better than those of Comparative Examples. It can be seen that the use of starch instead of is ineffective, but both G and I have lameness in both of the above performances, and the reaction product of alginic acids and acrylamide-based polymer and the mixture of both, It can be considered that they are almost the same, and the example in which the former is excellent indicates that the above can be made the same. In addition, both use itaconic acid, and it can be said that the use of itaconic acid is more effective. Also, from the results of Example 10 above, when the interlayer strength improvers G and I are used, G is superior to I, and the reaction product of alginic acids and acrylamide-based polymer is more effective than the mixture of both by calcium ions. I understand. In addition, from the results of Example 11 and Comparative Examples attached thereto, even in the neutral to alkaline papermaking, when the interlayer strength improver A was used, both of the above-mentioned performances were remarkably better than those of Comparative Examples. The effect of the addition of the reaction product of the acrylamide polymer is apparent. In addition, from the results of Example 12 and Comparative Examples accompanying the results, even when the papermaking system contains a filler other than calcium carbonate, when the interlayer strength improver A is used, the two performances are compared. The effect of the addition of the reaction product of alginic acid and acrylamide polymer is remarkably better than that of the examples. In the above examples, b5 monomer was also used as appropriate,
Almost the same effects can be obtained. In addition, sodium methallylsulfonate as the b4 component also functions as a chain transfer agent, and is preferable.

Further, from Example 13 and Comparative Example 21 attached thereto, the former is remarkably excellent in product stability, and when a product containing a reaction product of alginic acid and acrylamide polymer is used, starch and acrylamide are used. The product stability is excellent as compared with the case where the product containing the reaction product of the system polymer is used. Examples 14 to 19
From the results of Comparative Examples 22 and 23 accompanying the results, when the papermaking was performed by adding the internally added paper strength improvers f to l to the pulp slurry, the internal bond strength and the specific burst strength were both evaluated as follows. It is remarkably superior to Comparative Examples 23 and 24 which are not used. In the case of batch polymerization of monomers,
From the comparison between Example 16 and Examples 14 and 15, in the case of two-stage split charge polymerization of the monomer, from the comparison between Example 19 and Examples 17 and 18, all of the alginic acids and the acrylamide-based polymer were used. When a mixture of alginic acids and an acrylamide polymer is used, both the internal bond strength and the specific burst strength are superior to the case where a reaction product-containing product is used. Examples 17 to 1
From the comparison between Example 8 and Examples 14 and 15, as the acrylamide-based polymer reacted with alginic acids, those polymerized in two stages are particularly excellent in the above performance as compared with those polymerized at once, and Examples 19 and 16 According to the comparison, the acrylamide-based polymer mixed with alginic acid is polymerized in two steps as compared with the one polymerized at once, and the above-mentioned performance is particularly excellent in internal bond strength.

[0094]

According to the present invention, a novel combination of existing materials has a function of being used alone or in combination as a paper strength improver such as burst strength as well as an interlayer strength improver for multilayer paper. In addition, it can have a single or combined function as a paper strength improver or other paper modifier for paper such as internally added paper, and has excellent product stability, It is easy to prepare a modifier-containing liquid for
In addition, a paper modifier that can be easily treated for wastewater by the activated sludge method,
A paper containing the component and a method for producing the paper can be provided. Particularly as a paper modifier for multi-layer papermaking,
Those containing the reaction product of alginic acids and acrylamide-based polymers exhibit excellent interlayer strength improvement effects, and those containing a mixture of alginic acids and acrylamide-based polymers are excellent as paper additives for internal addition The effect of improving paper strength can be achieved, and the best results can be obtained by selectively using each of them.However, in the case of multi-layer papermaking, it is also possible to use both for improving interlayer strength and for internal addition in each of the papermaking processes . The product can be used for a wide range of applications.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification code FI Theme coat ゛ (Reference) D21H 27/00 D21H 27/00 E (72) Inventor Koji Kono 17-2 Yawata Kaigandori, Ichihara City, Chiba Prefecture Japan Within PCMC Corporation (72) Inventor Takahito Hirasawa 17-2 Yawata Kaigandori, Ichihara City, Chiba Prefecture Inside PCMC Corporation

Claims (14)

[Claims] 1. A water-soluble polysaccharide (A) containing at least alginic acid and at least acrylamide (b)
A paper modifier containing an acrylamide-based polymer (B) obtained by polymerizing the monomer containing 1). 2. A water-soluble polysaccharide (A) containing at least alginic acid and at least acrylamide (b)
The paper modifier according to claim 1, wherein the acrylamide-based polymer (B) obtained by polymerizing the monomer containing 1) is a separate body, and contains a mixture of both. 3. An acrylamide-based polymer (B) obtained by polymerizing a monomer containing at least acrylamides (b1) is obtained by polymerization in the presence of a water-soluble polysaccharide (A) containing at least alginic acids, A paper modifier containing the reaction product of the components (A) and (B). 4. An acrylamide polymer (B) obtained by polymerizing a monomer containing at least an acrylamide (b1) is obtained by copolymerizing a monomer containing an acrylamide (b1) and a cationic vinyl monomer (b2). The paper modifier according to any one of claims 1 to 3, which is a polymer obtained. 5. An acrylamide polymer (B) obtained by polymerizing a monomer containing at least an acrylamide (b1) is an acrylamide (b1), a cationic vinyl monomer (b2) and a polyfunctional vinyl monomer (b).
The paper modifier according to any one of claims 1 to 3, which is a polymer obtained by copolymerizing a monomer containing 3). 6. An acrylamide-based polymer (B) obtained by polymerizing a monomer containing at least an acrylamide (b1) comprises an acrylamide (b1), a cationic vinyl monomer (b2) and an anionic vinyl monomer (b4). The paper modifier according to any one of claims 1 to 3, which is a polymer obtained by copolymerizing a contained monomer. 7. An acrylamide polymer (B) obtained by polymerizing a monomer containing at least an acrylamide (b1) is an acrylamide (b1), a cationic vinyl monomer (b2), and a polyfunctional vinyl monomer (b).
3. A polymer obtained by copolymerizing 3) and a monomer containing an anionic vinyl monomer (b4).
4. The paper modifier according to any one of the above-mentioned items. 8. An acrylamide-based polymer (B) obtained by polymerizing a monomer containing at least 0.1 to 50% by weight of a water-soluble polysaccharide (A) containing at least alginic acid and at least a acrylamide (b1). The paper modifier according to any one of claims 1 to 7, which is 99.9 to 50% by weight. 9. A water-soluble polysaccharide (A) containing at least alginic acid according to claim 1.
And an acrylamide-based polymer (B) obtained by polymerizing a monomer containing at least an acrylamide (b1)
Containing paper. 10. A paper coating composition containing the paper modifier according to claim 1, which is applied to the surface of the prepared wet paper to form a plurality of wet papers. A method for producing a multilayer paper by using a modifier for use as an interlayer strength improver. 11. The method for producing paper according to claim 10, wherein the interlayer strength improver contains a calcium compound. 12. The method for producing paper according to claim 10, wherein one of the plurality of wet papers contains calcium carbonate. 13. A water-soluble polysaccharide (A) containing at least alginic acid according to claim 1.
And an acrylamide-based polymer (B) obtained by polymerizing a monomer containing at least an acrylamide (b1)
A method for producing paper, comprising: adding pulp slurry to pulp slurry to make paper. 14. A method for producing paper, comprising the step of adding the modifier for paper according to any one of claims 1 to 8 to a pulp slurry to make paper.