JPH0841797A - Additive for papermaking and method for papermaking - Google Patents

Abstract

PURPOSE:To obtain an additive for papermaking capable of providing excellent freeness and yield in a papermaking process and further paper excellent in paper strength. CONSTITUTION:This additive for papermaking contains a water-soluble copolymer prepared by reacting (a) acrylamides with (b) a vinyl monomer, having a cationic group copolymerizable with the component (a), (c) at least one of a tri- or a tetravalent unsaturated carboxylic acid copolymerizable with the components (a) and (b) or their salts, and (d) a cross-linking compound, or a copolymer obtained by reacting the components (a), (b), (c) and (d) with (e) a nonionic vinyl monomer or/and (f) an anionic vinyl monomer. Furtherthermore, the method for papermaking in a neutral or an alkaline pH region is to use this additive. Thereby, excellent freeness, yield and enhancing effects on paper strength are manifested.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyacrylamide papermaking additive and a papermaking method using the same. More specifically, it relates to a papermaking additive capable of exhibiting excellent drainage, retention and paper strength enhancing effects in a papermaking system in an acidic to neutral to alkaline pH range, and a papermaking method using the papermaking additive.

[0002]

2. Description of the Related Art Conventionally, in the papermaking process, various papermaking additives have been used in order to improve the productivity and the quality of the paper with the speeding up of the papermaking machine. Above all,
Paper strength enhancers, drainage improvers, retention improvers and the like are important chemicals for improving paper quality and productivity, and the range of use thereof is further widened, and improvements of these chemicals are also in progress. Behind this, there are restrictions on the use of virgin pulp due to the deterioration of raw wood supply conditions, and the need to use recycled paper has become stronger for the purpose of energy saving and effective use of resources, and due to wastewater regulations, etc. The closed rate has increased and the amount of contaminants has increased.

Starch, polyamide polyamine-epichlorohydrin resin, melamine formaldehyde resin, urea formaldehyde resin, and acrylamide copolymer having acrylamide as a main component are used as additives for papermaking according to the purpose. However, acrylamide-based copolymers are most widely used because of their synthetic advantages, performance, and ease of use.

As an additive for paper making comprising an acrylamide-based copolymer, an anionic type additive due to its ionic property,
Cationic types and amphoteric types are known. Examples of the anion type include a copolymer of acrylamides and a vinyl monomer having an anion group, a partial hydrolyzate of an acrylamide copolymer, and the like. Examples of the cation type include copolymers of acrylamides and vinyl monomers having a cationic group, and Hoffmann-modified Mannich-modified products of acrylamide-based copolymers.
As the amphoteric type, a vinyl monomer having an acrylamide and a cationic group and a vinyl monomer having an anionic group, a copolymer of a nonionic vinyl monomer which can be copolymerized with these monomers as necessary, an acrylamide and an anionic group are used. Examples thereof include a Hoffmann modified product of a copolymer with a vinyl monomer, or a Mannich modified product.

[0005]

However, in the papermaking industry in recent years, the above-mentioned deterioration of the raw material situation of paper, the speeding up of the papermaking machine, the increase of the amount of impurities in white water generated during the papermaking process and the increase of the papermaking pH. It has various problems related to paper quality such as fluctuation. In particular, with the speeding up of paper machines, further drying properties are required. Conventional additives for papermaking have not been able to sufficiently solve these problems. That is, the advent of a papermaking additive having a good balance in drainage, retention and paper strength improving effects has been awaited.

The present invention is a trivalent or trivalent compound capable of imparting excellent drainage, retention and paper strength enhancing effects in the acidic to neutral to alkaline pH range as compared with conventionally known acrylamide copolymer additives for papermaking. The present invention provides a papermaking additive containing a novel acrylamide-based copolymer containing a tetravalent unsaturated carboxylic acid or a salt thereof, and is excellent in drainage, retention and paper strength enhancing effect in a papermaking system. It is an object of the present invention to provide a papermaking method using the above-mentioned papermaking additive.

[0007]

Means for Solving the Problems The inventors of the present invention have conducted extensive studies to solve the above problems, and as a result, trivalent or tetravalent unsaturated carboxylic acids which have not been used in conventional papermaking additives have been found. Alternatively, these salts have been successfully introduced into the acrylamide copolymer, and the present invention has been completed.

That is, according to the present invention, a vinyl monomer (b) having a cationic group copolymerizable with the acrylamides (a) and (a), a trivalent copolymerizable with the (a) and (b) components, or A papermaking additive containing a water-soluble copolymer obtained by reacting at least one of a tetravalent unsaturated carboxylic acid or a salt thereof (c) with a crosslinkable compound (d), and the above (a), A papermaking additive containing a water-soluble copolymer obtained by reacting components (b) and (c) with a nonionic vinyl monomer (e) copolymerizable with each of these components and a crosslinkable compound (d), And the above (a), (b),
A papermaking additive containing a component (c) and a water-soluble copolymer obtained by reacting an anionic vinyl monomer (f) other than the component (c) copolymerizable with these components and a crosslinkable compound (d). Agent, and (a), (b), (c),
A papermaking additive containing a water-soluble copolymer obtained by reacting components (e) and (f) with a crosslinkable compound (d), and a papermaking process in which the papermaking additive is added to a pulp slurry. It provides a method.

Next, the present invention will be described in detail. In the present invention, the acrylamides (a) include N-methyl (meth) acrylamide, N-ethyl (meth) acrylamide, N, N in addition to acrylamide and methacrylamide.
-N-substituted acrylamides such as dimethyl (meth) acrylamide, N-isopropyl (meth) acrylamide, Nt-octyl (meth) acrylamide and the like,
These 1 type can be used individually or in combination of 2 or more types.

Examples of the vinyl monomer (b) having a cation group include dimethylaminoethyl (meth)
Acrylate, diethylaminoethyl (meth) acrylate, dimethylaminopropyl (meth) acrylate,
Vinyl monomers having a tertiary amino group such as diethylaminopropyl (meth) acrylate, dimethylaminopropyl (meth) acrylamide or diethylaminopropyl (meth) acrylamide, allylamine and diallylamine, or their inorganics such as hydrochloric acid, sulfuric acid, formic acid and acetic acid. Acids or organic acid salts, or a vinyl monomer containing the tertiary amino group and an alkyl halide such as methyl chloride or methyl bromide, an arylalkyl halide such as benzyl chloride or benzyl bromide, dimethylsulfate, diethylsulfate, epichlorohydrin, 3 -A quaternary ammonium salt obtained by reaction with a quaternizing agent such as chloro-2-hydroxypropyltrimethylammonium chloride or glycidyltrialkylammonium chloride. Vinyl monomers, such as 2-hydroxyethyl -N to, N, N, N ', N'-pentamethyl -
N '-[3-{(1-oxo-2-propenyl) amino} propyl] -1,3-propanediaminium dichloride and the like are exemplified, and these can be used alone or in combination of two or more.

Typical examples of the above-mentioned trivalent or tetravalent unsaturated carboxylic acid or salts thereof (c) include 1-propene-1,2,3-tricarboxylic acid and 1-propene.
Butene-1,2,3-tricarboxylic acid, 1-butene-
1,2,4-tricarboxylic acid, 2-butene-1,2,3
-Tricarboxylic acid, 2-butene-1,2,4-tricarboxylic acid, 3-butene-1,2,3-tricarboxylic acid, 4
-Pentene-1,2,4-tricarboxylic acid and other trivalent unsaturated carboxylic acids, 1-pentene-1,1,4,4-tetracarboxylic acid, 4-pentene-1,2,3,4-tetracarboxylic acid Examples thereof include acids, tetravalent unsaturated carboxylic acids such as 3-hexene-1,1,6,6-tetracarboxylic acid, various alkali metal salts such as sodium and potassium salts, ammonium salts and the like. These trivalent or tetravalent unsaturated carboxylic acids or salts thereof can be used alone or in combination of two or more.

Examples of the crosslinkable compound (d) include di (meth) acrylates such as ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate and propylene glycol di (meth) acrylate. Acrylates,
Methylenebis (meth) acrylamide, ethylenebis (meth) acrylamide, hexamethylenebis (meth)
Acrylamide, N, N'-bisacrylamide acetic acid,
Bis (meth) acrylamides such as methyl N, N′-bisacrylamide, N, N-benzylidenebisacrylamide, divinyl adipate, divinyl sebacate, divinyl esters, epoxy acrylates, urethane acrylates, allyl (meth) ) Acrylate,
Diallyl phthalate, diallyl malate, diallyl succinate, diallyl acrylamide, divinylbenzene, diisopropylbenzene, diallylamine, N, N
-Difunctional vinyl monomers such as diallylmethacrylamide, N-methylolacrylamide, diallyldimethylammonium, diallylchlorendate, glycidyl (meth) acrylate, 1,3,5-triacryloylhexahydro-S-triazine, triallyl isocyanate Trifunctional vinyl monomers such as nurate, N, N-diallylacrylamide, triallylamine and triallyl trimellitate, tetramethylolmethane tetraacrylate,
Tetrafunctional vinyl monomers such as tetraallylpyromellitate, N, N, N ′, N′-tetraallyl-1,4-diaminobutane, tetraallylamine salt, and tetraallyloxyethane,

Water-soluble substances such as tetramethylolmethane-tri-β-aziridinylpropionate, trimethylolpropane-tri-β-aziridinylpropionate and 4,4'-bis (ethyleneiminecarbonylamino) diphenylmethane Water-soluble polyfunctional epoxy compounds such as aziridinyl compounds, (poly) ethylene glycol diglycidyl ether, (poly) propylene glycol diglycidyl ether, (poly) glycerin diglycidyl ether, (poly) glycerin triglycidyl ether,

And 3- (meth) acryloxymethyltrimethoxysilane, 3- (meth) acryloxypropyldimethoxymethylsilane, 3- (meth) acryloxypropyltrimethoxysilane, 3- (meth) acryloxypropylmethyldi Chlorosilane, 3- (meth) acryloxyoctadecyltriacetoxysilane, 3- (meth) acryloxy-2,5-dimethylhexyldiacetoxymethylsilane, 3- (meth) acrylamidopropyltrimethoxysilane, 2- (meth) acrylamidoethyl. Trimethoxysilane, 1- (meth) acrylamidemethyltrimethoxysilane, 2- (meth) acrylamide-2
-Methylpropyltrimethoxysilane, 2- (meth) acrylamido-2-methylethyltrimethoxysilane,

2- (meth) acrylamidoisopropyltrimethoxysilane, 3- (meth) acrylamidopropyltriethoxysilane, N- (2- (meth) acrylamidoethyl) aminopropyltrimethoxysilane,
(3- (meth) acrylamidopropyl) oxypropyltrimethoxysilane, 3- (N-methyl (meth) acrylamide) propyltrimethoxysilane, 3-((meth) acrylamide-methoxy) -3-hydroxypropyltrimethoxysilane, 3-((meth) acrylamide-methoxy) propyltrimethoxysilane, 3- (vinylbenzylaminopropyl) trimethoxysilane, dimethyl-3- (meth) acrylamide-propyl-3-
(Trimethoxysilyl) -propylammonium chloride, dimethyl-2- (meth) acrylamido-2-methylpropyl-3- (trimethoxysilyl) -propylammonium chloride, 3- (meth) acrylamidopropylmethyldimethoxysilane, 3- ( (Meth) acrylamidopropyldimethylmethoxysilane, 3- (meth) acrylamidopropylisobutyldimethoxysilane, 2- (meth) acrylamidopropylisobutyldimethoxysilane,

2- (meth) acrylamido-2-methylpropyl monochlorodimethoxysilane, 2- (meth) acrylamido-2-methylpropylhydrogendimethoxysilane, 3- (meth) acrylamidopropylbenzyldiethoxysilane, 3- (meta ) Acrylamidopropyltriacetoxysilane, 2- (meth) acrylamidoethyltriacetoxysilane, 4- (meth) acrylamidobutyltriacetoxysilane, 2- (meth)
Acrylamido-2-methylpropyltriacetoxysilane, N- (2- (meth) acrylamidoethyl) aminopropyltriacetoxysilane, 2- (N-ethyl (meth) acrylamide) ethyltriacetoxysilane, 3- (meth) acrylamidopropyl Octyldiacetoxysilane, 1- (meth) acrylamidomethylphenyldiacetoxysilane, 3- (meth) acrylamidopropyltripropionyloxysilane, 3- (meth)
Acrylamidopropyltri (N-methylaminoethoxy) silane, vinyltrichlorosilane, vinylmethyldichlorosilane, divinyldichlorosilane,

Vinylphenyldichlorosilane, vinyldimethylchlorosilane, vinylmethylphenylchlorosilane, vinyldiphenylchlorosilane, vinyltrimethoxysilane, vinylmethyldimethoxysilane, vinylisobutyldimethoxysilane, vinyldimethylmethoxysilane, vinyltriethoxysilane, 3-vinylbenzyl. Aminopropyltriethoxysilane, vinylmethyldiethoxysilane, divinyldiethoxysilane, vinyldimethylethoxysilane, vinyldiphenylethoxysilane,
Vinyltriisopropoxysilane, vinyltributoxysilane, vinyldimethylisobutoxysilane, vinyltriphenoxysilane, vinyldimethyl (3-aminophenoxy) silane, vinyldimethyl (4-aminophenoxy) silane, vinyldimethyl (3-methyl-4) -Chlorophenoxy) silane, vinyldimethyl (2-methyl-4)
Examples thereof include silicon compounds such as -chlorophenoxy) silane, vinyltriacetoxysilane, vinylmethyldiacetoxysilane, and vinyldimethylacetoxysilane.

Examples of the nonionic vinyl monomer (e) include esters of alcohol and (meth) acrylic acid, (meth) acrylonitrile, styrene, styrene derivatives, vinyl acetate, vinyl propionate, methyl vinyl ether and the like.

As the anionic monomer (f) other than the above-mentioned trivalent or tetravalent unsaturated carboxylic acid or salts thereof (c), a monovalent unsaturated carboxylic acid such as (meth) acrylic acid or crotonic acid, Divalent unsaturated carboxylic acids such as maleic acid, fumaric acid, itaconic acid, muconic acid and citraconic acid, and organic sulfones such as vinylsulfonic acid, styrenesulfonic acid, allylsulfonic acid and 2-acrylamido-2-methylpropanesulfonic acid. Examples thereof include acids, alkali metal salts such as sodium and potassium salts of these various organic acids, ammonium salts and the like.

In the present invention, the amount of each of the components (a) to (f) to be used must be determined in due consideration of the performance of the resulting aqueous copolymer solution as an additive for papermaking. The following range is preferable.

(I) In the papermaking additive comprising the above components (a), (b), (c) and (d), the amount of the component (a) used is the amount of the monomers (a) and (b) used. And usually 98.9 to 7 based on the total molar amount of the component (c).
0 mol%, preferably 97.9-80 mol%, and likewise, the component (b) is usually 1-20 mol%, preferably 2 mol%.
Similarly, the amount of the component (c) used is usually 0.1 to 10 mol%, preferably 0.1 to 5 mol%. The amount of the component (d) used is usually 0.05 to 5 mol% based on the total molar amount of the monomers (a), (b) and (c) used.

(II) The above (a), (b), (c),
In the papermaking additive comprising the components (d) and (e),
The amount of the component (a) used is as follows:
It is usually 98.8 to 50 mol%, preferably 97.8 to 6 based on the total molar amount of the components (b), (c) and (e).
5 mol%, the component (b) is usually 1 to 20 mol%, preferably 2 to 15 mol%, and (c) is the same.
The amount of the component used is usually 0.1 to 10 mol%, preferably 0.1 to 5 mol%, and similarly, the component (e) is usually 0.1 to 20 mol%, preferably 0.1 to 20 mol%. It is 15 mol%. The amount of the component (d) used is usually 0.05 to 5 mol% based on the total molar amount of the monomers (a), (b), (c) and (e) used.

(III) The above (a), (b), (c),
In the papermaking additive comprising the components (d) and (f),
The amount of the component (a) used is as follows:
Usually 98.8-60 mol%, preferably 97.8-7, based on the total molar amount of components (b), (c) and (f).
5 mol%, the component (b) is usually 1 to 20 mol%, preferably 2 to 15 mol%, and (c) is the same.
The amount of the component used is usually 0.1 to 10 mol%, preferably 0.1 to 5 mol%, and the component (f) is usually 0.1 to 10 mol%, preferably 0.1 to 10 mol%. It is 5 mol%. The amount of the component (d) used is usually 0.05 to 5 mol% based on the total molar amount of the monomers (a), (b), (c) and (f) used.

(IV) The above (a), (b), (c),
In the papermaking additive comprising components (d), (e) and (f), the amount of the component (a) used is such that the monomers (a), (b), (c), (e) and (f) are used. ) Is usually 98.7 to 40 mol%, preferably 97.7 to 60 mol%, based on the total molar amount of the components), and likewise, the component (b) is usually 1 to 20 mol%, preferably 2 to 15 mol%, and the amount of the component (c) used is usually 0.1-10.
Mol%, preferably 0.1 to 5 mol%, likewise the component (e) is usually 0.1 to 20 mol%, preferably 0.1 to 15 mol%, and likewise the component (f). Is usually 0.1 to 10 mol%, preferably 0.1 to 5 mol%. The amount of the component (d) used is usually 0.05 to 5 mol% based on the total molar amount of the monomers (a), (b), (c), (e) and (f) used. is there.

The amount of the component (c) used is such that the monomers (a), (b), (c) or (a), (b),
(C), (e) or (a), (b), (c),
(F) or (a), (b), (c), (e),
When it is less than 0.1 mol% based on the total molar amount of the component (f), the drainage, retention and paper strength enhancing effects may be low, which is not preferable. Similarly, if it exceeds 10 mol%, drainage, retention and paper strength will not be improved to a certain extent or more, or the cost will be increased, which is not preferable.
The acrylamide copolymer used in the present invention can be synthesized by various conventionally known methods. For example, in a predetermined reaction container, the monomer concentration is 2 to 30% by weight,
(A) so as to be preferably 5 to 30% by weight,
(B), (c), (d), (e) and (f) components and water are charged, a radical polymerization initiator is added, and if necessary, alkyl mercaptans, thioglycolic acid or its esters, isopropyl alcohol. The desired acrylamide-based copolymer can be obtained by appropriately using a known chain transfer agent such as allylic alcohol, and heating with stirring.

As the radical polymerization initiator, persulfates such as sodium persulfate, potassium persulfate and ammonium persulfate, hydrogen peroxide, benzoyl peroxide, peroxides such as tert-butyl peroxide, sodium bromate and bromic acid. Bromates such as potassium, sodium perborate, potassium perborate, perborates such as ammonium perborate, sodium percarbonate, potassium percarbonate, percarbonates such as ammonium percarbonate, sodium perphosphate, Examples thereof include perphosphate salts such as potassium perphosphate and ammonium perphosphate. In this case, although it can be used alone, it can also be used as a redox polymerization initiator in combination with a reducing agent.

Examples of the reducing agent include sulfites, hydrogen sulfites, organic amines such as N, N, N ′, N′-tetramethylethylenediamine, and azo compounds such as 2,2′-azobis-2-amidinopropane hydrochloride. And reducing sugars such as aldose and the like. Also, azobisisobutyronitrile, 2,2'-azobis-2-amidinopropane hydrochloride, 2,2'-azobis-2,4-dimethylvaleronitrile, 4,4'-azobis-4-cyanovaleic acid and Azo compounds such as salts thereof can also be used. It is also possible to use two or more of these initiators in combination. From the viewpoint of workability, the viscosity of the obtained acrylamide copolymer is usually 15,000 cp with a Brookfield rotational viscometer.
It is preferably s or less.

The papermaking additive of the present invention is used, for example, by adding it to the wet end portion in the paper or paperboard manufacturing process. Specifically, it is possible to use the papermaking additive of the present invention in an aqueous dispersion of pulp in an amount of 0.01 to 7% by solid weight based on the dry weight thereof, and generally 0.05 to 2 Solid content weight% is added. It is also possible to spray wet paper before the drying step for the purpose of increasing paper strength. The sulfuric acid band may or may not be used depending on the type of paper. Further, the pH of papermaking may be appropriately adjusted by adding an alkaline substance or an acidic substance. The papermaking additive of the present invention can be used in a wide pH range from acidic to neutral to alkaline pH range, and particularly exhibits excellent effects in the neutral to alkaline pH range.

In the present invention, when the papermaking additive is used in a papermaking system using calcium carbonate as a filler, calcium carbonate is generally used in an amount of 5 to 30% based on the dry weight of pulp, and papermaking is performed at a pH of 7 to 9. . The above-mentioned papermaking additive is added in an amount of 0.01 to 7%, and generally 0.05 to 2%, similarly to the above. The sulfuric acid band can also be added in a papermaking system using calcium carbonate.

According to the papermaking method of the present invention, not only the production of paper / paperboard having excellent paper quality in an acidic papermaking system in which a large amount of sulfuric acid band is added, but also a papermaking system in which calcium carbonate is mixed from a waste paper raw material such as gypsum Board base paper, coat base paper, medium quality paper,
Can not use general liner, core, sulfuric acid band,
Papermaking system whose use amount is limited to a small amount, for example, neutral pure white roll paper, neutral liner, anticorrosion liner and metal interleaving paper,
It can also be used in papermaking systems where the amount of fixing agent used is limited, such as kraft paper.

Paper making systems using calcium carbonate as a filler, such as neutral printing writing paper, neutral coated base paper, neutral P
It is possible to obtain paper of the above-mentioned excellent paper quality in PC paper, neutral heat-sensitive base paper, neutral pressure-sensitive base paper, neutral inkjet paper, and neutral information paper.

In the production of the above various papers or paperboards in the acidic to neutral or alkaline pH range, pulp raw materials such as bleached or unbleached chemical pulp, groundwood pulp, mechanical pulp or thermomechanical such as kraft pulp or sulfite pulp are used. Any of bleached or unbleached high-yield pulp such as pulp, used newspaper, used magazine, used corrugated paper, and used paper pulp such as deinked used paper can be used. Further, a mixture of the above pulp raw material with asbestos, rock wool, polyamide, polyester, polyolefin and the like can also be used.

Fillers, dyes, rosin-based sizing agents for acidic papermaking, alkyl ketene dimer-based or alkenyl succinic anhydride-based sizing agents for neutral papermaking, rosin-based sizing agents for neutral papermaking, etc., improving dry paper strength. Additives such as agents, wet paper strength improvers, retention improvers, drainage improvers, defoamers, etc. may be used as necessary to develop the physical properties required for each paper type. . Examples of the filler include clay, talc, titanium oxide, heavy or light calcium carbonate, and these may be used alone or in combination.

[0034]

EXAMPLES The present invention will be described in more detail with reference to Examples and Comparative Examples. All percentages are by weight.

Example 1 In a 1-liter four-necked flask equipped with a stirrer, a thermometer, a reflux condenser and a nitrogen gas inlet tube, 199.86 g (93.7 mol%) of 50% aqueous acrylamide solution and dimethylaminoethyl methacrylate were added. 11.79 g (5 mol%), 3-butene-1,2,3 tricarboxylic acid 3.67
g (1.3 mol%), 1% methylenebisacrylamide aqueous solution 5.78 g (0.025 mol%), isopropyl alcohol 22.53 g, water 342.05 g, 20% sulfuric acid aqueous solution 19.48 g were charged to pH 3.0. The temperature was raised to 55 ° C. under introduction of nitrogen gas, 3.42 g of a 5% ammonium persulfate aqueous solution and 3.56 g of a 2% sodium metabisulfite aqueous solution were added, and the mixture was reacted at 80 ° C. for 2 hours to give a solid content of 20.4%, Viscosity (25 ° C) 7800 cps, pH 3.
An aqueous solution of the copolymer of 7 was obtained. This is designated as Papermaking Additive A.

The properties of the resulting aqueous copolymer solution are shown in Table 1. The symbols used in Table 1 have the following meanings. AAm: Acrylamide MAAm: Methacrylamide DM: Dimethylaminoethylmethacrylate DPA: Dimethylaminopropylacrylamide DMBz: Methacryloyloxyethyl dimethylbenzylammonium chloride DMC: Methacryloyloxyethyl trimethylammonium chloride BTCA: 3-Butene-1,2,3- Tricarboxylic acid PTCA: 4-Pentene-1,2,4-tricarboxylic acid IA: Itaconic acid AAc: Acrylic acid MBAAm: Methylenebisacrylamide AN: Acrylonitrile VTES: Vinyltriethoxysilane

[0037]

[Table 1]

Examples 2 to 7 and Comparative Examples 1 to 2 In Example 1, as shown in Table 1, the types and amounts of the components (a) to (f) were changed, and the type and amount of the polymerization initiator and isopropyl were used. The same operation as in Example 1 was carried out except that the amount of alcohol was changed to obtain respective copolymer aqueous solutions.
Table 1 shows the properties of the aqueous copolymer solutions obtained in Examples 2 to 7 and Comparative Examples 1 and 2. In Comparative Example 1, (c),
This is an example in which acrylic acid is used as the component (f) without the component (e), and Comparative Example 2 is an example in which itaconic acid is used as the component (f) instead of the acrylic acid in Comparative Example 1.

Examples 8 to 14 and Comparative Examples 3 and 4 (comparison with a papermaking pH of 6.5 using a sulfuric acid band) and Examples 15 to 21 and Comparative Examples 5 and 6 (a sulfuric acid band was used). (Comparison with corrugated cardboard waste paper system with papermaking pH 5.0) Beating degree obtained from corrugated cardboard waste paper (Canadian Standard Freeness, abbreviated as CSF) 400
A pulp slurry having a pH of 6.5 was prepared by adding 1.0% of a sulfuric acid band to pulp to a pulp slurry having a concentration of 2.4% and adjusted to ml (Examples 8 to 14 and Comparative Example 3, 4). In addition, C.I.
S. F. A pulp slurry having a pH of 5.0 was prepared by adding 1.5% of a sulfuric acid band to pulp to a pulp slurry having a concentration of 2.4% adjusted to 400 ml (Examples 15 to 21 and Comparative Examples 5 and 6). for).

Next, the respective acrylamide copolymer aqueous solutions obtained in Examples 1 to 7 and Comparative Examples 1 to 2, that is, the papermaking additives (A to
0.6% of I) was added to the pulp, and after stirring,
Dilute the pulp slurry concentration to 0.25%,
Papermaking with Noble and Wood sheet machine,
Dry with a drum dryer at 110 ° C for 90 seconds to obtain a basis weight of 80 g / m ² (for burst strength measurement) and 170 g / m ²
Two kinds of handmade papers (for measuring compression strength) were obtained. The obtained paper material had a R. H. After conditioning the humidity for 24 hours under the conditions described above, each physical property was measured. The addition rate of the above chemicals is the weight ratio of solid content to absolutely dry weight of pulp.

The measurement results are shown in Tables 2 and 3. Table 2 and Table 3
The physical properties shown in were measured according to the following methods. (1) DDT ... Tappi journal No. 5
Using a device similar to "Dynamic Drainage Jar" described on page 46 of Volume 6, No. 10 (1973), 500 ml of pulp slurry was poured into a jar having a diameter of 7.5 cm and stirred at 800 rpm. While the lower cock is opened, filtration is performed with a 100-mesh wire net, and the time until the amount of the filtrate becomes constant is measured, which can be used for evaluation of drainage. Here, the time until the amount of filtrate reaches 250 g was measured.

(2) RDDT ... Tappi Pa
permakers Conference (1985
Year), page 171.
Hercules Dynamic Drainage
Using the same device as Tester (pulp slurry is poured into a jar with a diameter of 7.5 cm, air is blown from the bottom under stirring at 800 rpm so as not to form a mat, stirring and air feeding are stopped, and filtration is performed at the same time) Then, pour 500 ml of pulp slurry into the jar and
1 was taken and the transmittance at 620 nm (TM;
%) Is measured. As a parameter of the fast path retention, this T.S. M. (%) Was used. That is, T. M. The higher (%) indicates that the filtrate is transparent and that the yield of the filler and the fine fibers is higher. (3) Specific compressive strength ... JIS P 8126 (4) Specific burst strength ... JIS P 8112

Examples 22 to 28, Comparative Examples 7 and 8 (papermaking p
(Comparison with papermaking system using H8.0 calcium carbonate)
And Examples 29 to 35, Comparative Examples 9 and 10 (papermaking pH 7.
(Comparison in a papermaking system using calcium carbonate of 0) BKP L / N = 8/2 C.I. S. F. 400 ml
Calcium carbonate (Tama Pearl-121S: Okutama Kogyo Co., Ltd.)
, And sulfuric acid bands were added to the pulp at 12% and 0.5% respectively to prepare pulp slurries having a pH of 8.0 (for Examples 22 to 28 and Comparative Examples 7 and 8). Also, C.I. with BKP L / N = 8/2. S. F. 400
To a pulp slurry with a concentration of 2.4% adjusted to ml,
Calcium carbonate (Tama Pearl-121S: manufactured by Okutama Kogyo Co., Ltd.) and sulfuric acid band were respectively added to the pulp in an amount of 1
Pulp slurries having a pH of 7.0 were prepared by adding 2% and 1.5% (Examples 29 to 35 and Comparative Examples 9 and 10).
for).

Then, the papermaking additives (A to I) obtained in Examples 1 to 7 and Comparative Examples 1 to 2 were added to the respective pulp slurries at 0.6% and stirred. After that, the pulp slurry concentration was diluted to 0.25%, paper was made with a Noble and Wood sheet machine, dried with a drum dryer at 110 ° C. for 90 seconds, and the basis weight was 80 g / m ² . A papermaking paper was obtained. The obtained sample had a R. H. After conditioning the humidity for 24 hours under the conditions described above, each physical property was measured. In addition, the addition rate of the above chemicals is the weight ratio of solid content to absolutely dry weight of pulp. The measurement results are shown in Tables 4 and 5. The physical properties shown in Tables 4 and 5 were measured according to the following methods. DDT and RDDT were measured by the same method as above.

(5) Scott Bond: An internal bond tester (manufactured by Kumagai Riki Kogyo Co., Ltd.) was used and the bond strength was 100 kg / cm ² and the time was 30 seconds. (6) Breaking length: JIS P8113

[0046]

[Table 2]

[0047]

[Table 3]

[0048]

[Table 4]

[0049]

[Table 5]

[0050]

As is clear from the results shown in Tables 2, 3, 4, and 5, the papermaking additive of the present invention is superior to the chemicals used in Comparative Examples in the drainage property in the papermaking process. It is also clear that the yield is obtained and the paper strength after papermaking is excellent. In particular, it is clear that by using the papermaking additive of the present invention in a papermaking method for making paper in a neutral to alkaline pH range, excellent drainage, retention, and paper strength enhancing effects are exhibited. .

Front Page Continuation (72) Inventor Satoshi Takizawa 17-2 Yawata Kaigan Dori, Ichihara City, Chiba Prefecture Japan PMC Co., Ltd.

Claims (8)

[Claims] 1. A trivalent or tetravalent monomer which is copolymerizable with vinyl monomers (b), (a) and (b) having a cationic group copolymerizable with acrylamides (a) and (a). A papermaking additive containing a water-soluble copolymer obtained by reacting at least one kind of a saturated carboxylic acid or a salt thereof (c) and a crosslinkable compound (d). 2. A trivalent or tetravalent monomer which is copolymerizable with the vinyl monomers (b), (a) and (b) having a cationic group copolymerizable with the acrylamides (a) and (a). A saturated carboxylic acid or at least one salt thereof (c), a crosslinkable compound (d), and a nonionic vinyl monomer (e) copolymerizable with the above-mentioned components (a), (b) and (c). An additive for papermaking, comprising a water-soluble copolymer obtained by the reaction. 3. A trivalent or tetravalent monomer which is copolymerizable with the vinyl monomers (b), (a) and (b) having a cationic group copolymerizable with the acrylamides (a) and (a). At least one saturated carboxylic acid or salt thereof (c), a crosslinkable compound (d), and (a),
An additive for papermaking comprising a water-soluble copolymer obtained by reacting an anionic vinyl monomer (f) other than the component (c) which is copolymerizable with the components (b) and (c). 4. A trivalent or tetravalent monomer which is copolymerizable with the vinyl monomers (b), (a) and (b) having a cationic group copolymerizable with the acrylamides (a) and (a). At least one saturated carboxylic acid or salt thereof (c), a crosslinkable compound (d), the above (a),
Nonionic vinyl monomer (e) copolymerizable with components (b) and (c), and anion other than component (c) copolymerizable with components (a), (b), (c) and (e). An additive for papermaking, comprising a water-soluble copolymer obtained by reacting a polymerizable vinyl monomer (f). 5. An amount of at least one trivalent or tetravalent unsaturated carboxylic acid or salt thereof (c) used is
Based on the total molar amount of each component used except (d),
The papermaking additive according to any one of claims 1 to 4, wherein the additive is used in the range of 0.1 to 10 mol% and polymerized. 6. A tri- or tetra-valent unsaturated carboxylic acid or at least one salt thereof (c) is 3-butene-1,2,3-tricarboxylic acid, 4-pentene-1,
A 1,4-tricarboxylic acid or a salt thereof,
5. The papermaking additive according to any one of 5 above. 7. A papermaking method, which comprises using the papermaking additive according to any one of claims 1 to 6. 8. The paper-making method according to claim 7, wherein the paper-making additive is used in the neutral to alkaline pH range.