JP3483690B2 - Fluorescent whitening method for paper and pulp - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluorescent whitening method for paper and the like using a fluorescent whitening agent for paper and pulp, and a defluorescent treatment method for the obtained paper and pulp.

[0002]

BACKGROUND OF THE INVENTION Many fluorescent whitening agents for paper and pulp are known, but most of them are actually 4,4'-bistriazinylaminostilbene-2,2'-disulfonic acid type. It has a sufficient whitening effect. However, a bleaching process is required for the defluorescence process when reusing the waste paper fluorescently whitened with this product. There has been no known fluorescent whitening agent capable of defluorescence treatment of waste paper without bleaching, showing a high whitening effect, and having various fastnesses.

[0003]

[Problem to be Solved by the Invention] It has good fastness to paper and pulp, shows a high whitening effect, is easy to liquefy in water from the viewpoints of dust prevention and simplification of weighing, and is an alkaline agent when recycling waste paper. There was a demand for the development of a fluorescent whitening treatment method capable of defluorescence at the same time as the cooking treatment with lactic acid.

[0004]

The present invention is (1) The following formula (1) in the form of free acid

[0005]

[Chemical 4]

(In the formula (1), X represents a phenyl group which may have a sulfonic acid group, Y represents an alkoxy group having 1 to 5 carbon atoms, a hydroxyl group, a morpholino group, and a group represented by the following formula (2). Group or

[0007]

[Chemical 5]

(In the formula (2), R ₂ and R ₃ are each independently a hydrogen atom or an optionally substituted carbon atom having 1 to 5 carbon atoms.
1 to 8 carbon atoms optionally having a substituent
A group represented by the following formula (3):

[0009]

[Chemical 6]

(In the formula (3), the aromatic ring A represents a benzene ring or a naphthalene ring which may have a substituent, B represents O, S or NH, and n represents an integer of 0 to 3. ), Z represents a hydrogen atom or a methyl group, and a fluorescent whitening method for paper and pulp using a water-soluble coumarin compound having one or more sulfonic acid groups in the molecule (2) Particularly preferably, Fluorescent brightening method for paper and pulp using a coumarin compound represented by the formula (1), wherein X is a 2-sulfoanilino group which may have a substituent or a taurino group which may have a substituent. (3) Similarly, in the formula (1) of the preceding paragraph, a fluorescent whitening method for paper or pulp using a coumarin compound in which X is a phenoxy group or a naphthoxy group which may have a substituent (4) The preceding paragraph Paper and pulp obtained in (1) to (3) Regarding de fluorescence treatment with alkaline agents.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION In the coumarin compound represented by the formula (1), the number of carbon atoms which may have a substituent is 1 to Y.
Examples of the substituent of the 5 alkoxy group include a hydroxyl group, a methoxy group, an ethoxy group such as an alkoxy group having 1 to 5 carbon atoms, a hydroxyalkoxy group such as hydroxyethoxy having 1 to 5 carbon atoms, a phenyl group, and a sulfone group. Etc. Substituents of an alkyl group having 1 to 5 carbon atoms which may have a substituent, and R ₁ and R ₃ which have a substituent and have 1 to 8 carbon atoms, which are optionally substituted. Substituent of alkyl group and carbon number which may have a substituent 1 to
Examples of the substituent of the alkylaminoalkyl group of 8 include a hydroxyl group, a sulfonic acid group, a carboxyl group, a cyano group,
Examples thereof include aminocarbonyl group, phenyl group, sulfophenyl group and the like.

Specific examples of the optionally substituted alkoxy group having 1 to 5 carbon atoms in Y include, for example, a methoxy group, an ethoxy group, a propoxy group, a butoxy group, and 2
-Hydroxyethoxy group, 2-hydroxypropoxy group, 4-hydroxybutoxy group, 2-methoxyethoxy group, 2-ethoxyethoxy group, 2-methoxypropoxy group, 2- (2-hydroxyethoxy) ethoxy group, phenylethoxy group, Examples thereof include 2-sulfoethoxy group and 3-sulfopropoxy group. Specific examples of the alkyl group having 1 to 5 carbon atoms which may have a substituent in R ₂ and R ₃ of the formula (2) include, for example, methyl group, ethyl group, propyl group, butyl group, hydroxy group. Examples include ethyl group, dihydroxyethyl group, hydroxypropyl group, dihydroxypropyl group, sulfomethyl group, 2-sulfoethyl group, sulfophenylmethyl group, carboxyethyl group, cyanoethyl group, 2-aminocarbonylethyl group, benzyl group and phenethyl group. Specific examples of the alkoxyalkyl group having 1 to 8 carbon atoms which may have a substituent include, for example, methoxyethyl group, dimethoxyethyl group, ethoxyethyl group, diethoxyethyl group, ethoxypropyl group,
Examples thereof include a diethoxypropyl group and a butoxyethyl group. Specific examples of the alkylaminoalkyl group having 1 to 8 carbon atoms which may have a substituent include, for example, methylaminoethyl group, dimethylaminoethyl group, ethylaminoethyl group, diethylaminoethyl group, methylaminopropyl group, Examples thereof include an ethylaminopropyl group.

Specific examples of the group represented by formula (2) in Y include, for example, amino group, methylamino group, ethylamino group, propylamino group, butylamino group, t-butylamino group, hexylamino group. , Dimethylamino group,
Diethylamino group, dipropylamino group, dibutylamino group, hydroxyethylamino group, dihydroxyethylamino group, hydroxypropylamino group, dihydroxypropylamino group, sulfomethylamino group, carboxyethylamino group, N-ethyl-N- (cyanoethyl ) Amino group, N-ethyl-N- (2-aminocarbonylethyl) amino group, benzylamino group, phenethylamino group, N-ethyl-N-benzylamino group, N-ethyl-
N- (sulfophenylmethyl) amino group, 2-sulfoethylamino group, N-methyl-N- (2-sulfoethyl)
Amino group, methoxyethylamino group, dimethoxyethylamino group, ethoxyethylamino group, diethoxyethylamino group, ethoxypropylamino group, diethoxypropylamino group, butoxyethylamino group, methylaminoethylamino group, dimethylaminoethylamino group Group, ethylaminoethylamino group, diethylaminoethylamino group, di (methylaminoethyl) amino group, di (ethylaminoethyl) amino group, methylaminopropylamino group, ethylaminopropylamino group, allylamino group,
Examples thereof include a diallylamino group.

Specific examples of the group represented by formula (3) in Y include, for example, an anilino group, 2-, 3- or 4
-Methylanilino group, 2-, 3- or 4-ethylanilino group, 2,4-dimethylanilino group, 2,6-dimethylanilino group, 2,4,6-trimethylanilino group, 3
-Or 4-methoxyanilino group, 2-, 3- or 4
-Chloroanilino group, 4-carboxyanilino group, 4-
Methoxycarbonylanilino group, 2-, 3- or 4-
Sulfoanilino group, 2,4-disulfoanilino group, 2,
5-disulfoanilino group, 4-methyl-2-sulfoanilino group, 4-methyl-3-sulfoanilino group, 2-methyl-4-sulfoanilino group, 4-chloro-5-methyl-
2-sulfoanilino group, 4-chloro-3-sulfoanilino group, phenoxy group, 2-, 3- or 4-methylphenoxy group, 3- or 4-ethylphenoxy group, 2-,
3- or 4-chlorophenoxy group, 2,4-dimethylphenoxy group, 3- or 4-methoxyphenoxy group,
4-ethoxyphenoxy group, 2- or 4-carboxyphenoxy group, 4-methoxycarbonylphenoxy group,
4-ethoxycarbonylphenoxy group, 2-, 3- or 4-sulfophenoxy group, 2-methyl-4-sulfophenoxy group, 4-methyl-2-sulfophenoxy group, 4
-Methyl-3-sulfophenoxy group, 4-chloro-2-
Sulfophenoxy group, 2,4-disulfophenoxy group,
2,5-disulfophenoxy group, 1-naphthoxy group, 2
-Naphthoxy group, 4-methoxy-1-naphthoxy group, 4
-Carboxy-1-naphthoxy group, 3-carboxy-6
-Carboxy-2-naphthoxy group, 2-, 3-, 4-,
5-, 6-, 7- or 8-sulfo-1-naphthoxy group, 1-, 4-, 5-, 6-, 7- or 8-sulfo-
2-naphthoxy group, 2,4-di-, 3,6-di-, 3,3
7-di-, 3,8-di- or 4,7-disulfo-1-
Naphthoxy group, 3,6-di-, 6,8-di- or 4,
8-di-sulfo-2-naphthoxy group, 3,6,8-trisulfo-1-naphthoxy group, 3,6,8-trisulfo-
Examples thereof include a 2-naphthoxy group, a thiophenol group, a 2-, 3- or 4-methylthiophenol group and a thionaphthol group.

Of these substituents, preferred ones are, for example, Z is a hydrogen atom or a methyl group and Y is p.
-Sulfophenylamino group, 2-, 3- or 4-sulfophenoxy group, 2-methyl-4-sulfophenoxy group, 4-methyl-2-sulfophenoxy group, 4-methyl-3-sulfophenoxy group, 4- Chloro-2-sulfophenoxy group, 2,4-disulfophenoxy group, 2,5-
Disulfophenoxy group, 1-naphthoxy group, 2-naphthoxy group, 2-, 3-, 4-, 5-, 6-, 7- or 8
-Sulfo-1-naphthoxy group, 1-, 4-, 5-, 6
-, 7- or 8-sulfo-2-naphthoxy group, 2,4
-Di-, 3,6-di-, 3,7-di-, 3,8-di- or 4,7-di-1-naphthoxy group, 3,6-di-,
6,8-di- or 4,8-di-sulfo-2-naphthoxy group, 3,6,8-trisulfo-1-naphthoxy group,
3,6,8-trisulfo-2-naphthoxy group, 2-, 3
-Or 4-sulfoanilino group, 2,4-disulfoanilino group, 2,5-disulfoanilino group, 4-methyl-2
-Sulfoanilino group, 4-methyl-3-sulfoanilino group, 2-methyl-4-sulfoanilino group, 4-chloro-
Examples thereof include 5-methyl-2-sulfoanilino group. X
Is a phenyl group which may be substituted with a sulfonic acid group.
The specific examples thereof include a phenyl group and p-
A phenyl group having a sulfonic acid group at the m-position is preferred.
To be

Specific examples of the coumarin-based compound represented by the formula (1) of the present invention include the following compounds. In these formulas, the sulfonic acid group shall be represented in the form of the free acid.

[0017]

[Chemical 7]

[0018]

[Chemical 8]

[0019]

[Chemical 9]

[0020]

[Chemical 10]

[0021]

[Chemical 11]

[0022]

[Chemical 12]

[0023]

[Chemical 13]

[0024]

[Chemical 14]

The coumarin-based compound represented by the formula (1) used in the present invention has the formula (4)

[0026]

[Chemical 15]

The aminocoumarin compound of formula (4 has the same meaning as in formula (1)) and the compound of X-H are condensed with cyanuric chloride in a molar ratio of 1 mol each in any order. Alternatively, a dichlorotriazine derivative obtained by condensing a compound of X-H containing a sulfonic acid group and cyanuric chloride in a molar ratio of 7-amino-
3-phenylcoumarin or 7-amino-6-methyl-3
-It is obtained by condensing 1 molar ratio of phenylcoumarin. Here, X has the same meaning as in formula (1). This condensation reaction is carried out in a water solvent or using an inert solvent such as acetone or dimethylformamide, alone or in a mixture. When the reaction is carried out in suspension, the addition of surfactant is effective. Hydrogen chloride is liberated in the condensation reaction, so a neutralizer is added, but sodium, potassium,
Alkali metal hydroxides, carbonates, bicarbonates such as lithium are advantageously used. In addition, organic amines can also be used according to circumstances. The reaction temperature varies depending on the reactivity of the compound, but the primary condensation reaction is usually carried out at 0 to 20 ° C, and the secondary condensation reaction is carried out at 20 to 70 ° C. After completion of the reaction, the obtained coumarin compound of the formula (1) can be isolated by a generally known method (for example, salting-out, aciding-out, addition of an organic solvent), and optionally purified.

In order to obtain an aqueous liquid composition of the coumarin compound of the formula (1), the reaction liquid at the time of synthesizing the coumarin compound of the formula (1) is used as it is, or if necessary, desalting or concentration is carried out, or It is prepared by adding a solubilizing agent such as an organic solvent or a surfactant together with a pH buffer to the aqueous solution of the press cake taken out. These solubilizers also have the effect of improving whitening properties.

Specific examples of solubilizers that can be used include monoethanolamine, diethanolamine, triethanolamine, 3-propanolamine, 2-propanolamine, dipropanolamine, tripropanolamine, triisopropanolamine, diethylamine, triethylamine. , Methyldiethanolamine,
Ethyldiethanolamine, N-methylethanolamine, N-ethylethanolamine, N, N-dimethylethanolamine, N, N-diethylethanolamine,
Organic amines such as N-phenylethanolamine, urea, alkylurea, acid amide compounds such as ε-caprolactam, ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, polypropylene glycol, butylene glycol, Methyl cellosolve, carbitol, methyl carbitol, ethylene glycol dimethyl ether, ethylene glycol monobutyl ether, diethylene glycol monobutyl ether, triethylene glycol monobutyl ether, triethylene glycol monomethyl ether, propylene glycol monomethyl ether, butyl polyglycol,
Water-soluble organic solvents such as phenyl glycol, hexylene glycol, thioglycol, glycerin, tetrahydrofuran, dioxane, butyrolactone, N-methyl-2-pyrrolidone, formamide, dimethylformamide, methyl alcohol, ethyl alcohol, propyl alcohol, butyl alcohol, etc. Polyethylene glycol, polypropylene glycol, these copolymers, polyethylene glycol higher alcohol ether,
Examples thereof include nonionic surfactants such as polyethylene glycol octylphenol ether and polyethylene glycol alkylphenol ether such as polyethylene glycol nonylphenol ether. These solubilizers can be used alone or in combination of two or more. A concentrated solution can be easily obtained by treating the reaction-terminated liquid with an ultrafiltration membrane or a reverse osmosis membrane for desalting in order to facilitate liquefaction.

In the fluorescent whitening method of the present invention, it is preferable to use the coumarin compound of the formula (1) as the aqueous liquid composition, and the coumarin compound of the general formula (1) of the aqueous liquid composition is 5 to 35%, Solubilizing agent 0 to 50% (all by weight) is prepared by mixing an acid or base for adjusting the pH value of the solution to 5 to 7, a pH buffering agent if necessary, and water (remainder). . In addition, a fungicide and the like are added as needed. Specific examples of acids, bases and salts that can be used as a pH buffer include hydrochloric acid, sulfuric acid, horic acid, sodium hydroxide, potassium hydroxide, lithium hydroxide, sodium carbonate, potassium carbonate, sodium hydrogen carbonate, dihydrogen phosphate. Potassium, disodium hydrogen phosphate,
Inorganic substances such as acetic acid, lactic acid, malic acid, glycine,
Organic compounds such as methyldiethanolamine, drieternoramine, sodium diethylaniline-3-sulfonate may be mentioned.

The fluorescent whitening method for paper and pulp in the present invention includes the internal addition method in which a fluorescent whitening agent is added during or after the beating of the pulp until the papermaking process, and the size pressing step after the papermaking. It is roughly divided into methods such as adding a fluorescent whitening agent to the press solution or overcoating the surface of the paper with a coating solution prepared from a fluorescent whitening agent, an inorganic white pigment, a binder, etc., and both methods are applied. However, the latter method is more preferable.

In the internal addition method, pulp is first beaten with a pulper, a refiner or the like to a predetermined beating degree to form a pulp slurry, which is usually 0.01 to 2.0% (dry) at a temperature of 10 to 40 ° C. After adding an aqueous liquid composition of the coumarin-based compound of the formula (1) (purity amount per paper weight), and further adding an ordinary sizing agent, a sulfuric acid band, a paper strengthening agent, a sticking agent, etc., if necessary. After the paper making process and the drying process, the fluorescent whitened paper is obtained by a conventional method. or,
In the external addition method, pulp is first beaten with a pulper, refiner or the like to a predetermined beating degree to form a pulp slurry, and ordinary fillers, sizing agents, sulfuric acid bands, fixing agents, etc. are appropriately added, and then papermaking is performed by a conventional method. To do. Then, in a step of drying with a cylinder dryer, a coumarin-based compound of the formula (1) containing an aqueous solution composition of a formula (1) was prepared by a size press machine installed in the middle of the cylinder dryers (usually 20 to 60). By applying the above size press coating solution and then drying, a fluorescent whitened paper is obtained. The size press coating liquid in the above is an aqueous liquid composition of the coumarin-based compound of the formula (1) and starch,
It is prepared by appropriately mixing PVA, CMC, a surface sizing agent, water, etc., and has the formula (1) in the size press coating liquid.
Coumarin-based compound content is usually 0.04 to 2.0%
(Pure content), and the coating amount of the size press coating liquid is usually 1 to 3 g / m ² (solid content) per dry papermaking paper. The aqueous liquid composition of the coumarin-based compound of the formula (1) used in the present invention has a high affinity for paper (cellulosic fibers), and therefore has excellent color value (coloring density) and good fluorescent whitening power.

The paper obtained by using the coumarin-based compound of the formula (1) of the present invention for the fluorescent whitening treatment has high whiteness and good fastness such as light fastness and moisture fastness. In some cases, it may be advantageous to use a mixture of two or more coumarin compounds of formula (1). Higher whiteness can be obtained by using a small amount of fluorescent purple dye having affinity for paper and pulp. It is recommended because it may also improve light resistance. In order to recycle the waste paper obtained from the paper or pulp thus obtained or to reuse the pulp, a known method for treating with an alkali agent may be used. That is, for example, caustic soda, caustic potash, and sodium silicate are used as the alkaline agent, and in their aqueous solution, 10 to 70 ° C., preferably 30 to 60 ° C.
It may be immersed at 0.5 ° C. for 0.5 to 5 hours, or may be stirred if necessary. In this case, the concentration of the alkaline agent is usually 0.01 to 3
%, Preferably 0.5-2% by weight.

It is also possible to add an active oxygen generating agent to an aqueous solution of an alkaline agent for defluorescence treatment. Examples of the active oxygen generating agent include hydrogen peroxide, ozone, and agents capable of generating ozone. These are used as, for example, an aqueous hydrogen peroxide solution or an aqueous solution of a chemical capable of generating ozone. The active oxygen in the liquid containing the active oxygen generator is the concentration of active oxygen present in the aqueous solution having a hydrogen peroxide concentration of 1 to 8% by weight and an alkali concentration of 0 to 3% by weight in the hydrogen peroxide-based aqueous solution. A concentration equivalent to If necessary, a deinking agent may be added to the treatment bath in the defluorescence treatment method of the present invention to perform the defluorescence treatment and the decarbonization treatment at the same time.

[0035]

EXAMPLES Next, the present invention will be described more specifically by way of examples. In the examples, "part" means "part by weight" and "%" means "weight 5". The coumarin compound used in the present invention is produced as follows.

Production Example 1 19.0 parts of cyanuric chloride and 1 part containing 0.5 part of surfactant
Disperse by adding to 00 parts of ice water under stirring. While keeping this suspension at 5 ° C. or lower, 3 parts of an aqueous solution of 300 parts obtained by dissolving 29.7 parts of 2,5-disulfoaniline disodium was used.
The mixture was added dropwise over 0 minutes and then reacted at 5 to 10 ° C for 3 hours. During the dropping and during the reaction, the pH value was maintained at 3 to 4 with a 10% aqueous sodium hydroxide solution. Then heat to 30 ° C. and into this 7-amino-3-phenylcoumarin 22.
A solution prepared by dissolving 5 parts in 600 parts of acetone was added dropwise over 30 minutes and then reacted at 40 to 50 ° C. for about 3 hours. During the dropping and during the reaction, the pH was maintained at 4 to 6 with a 10% sodium carbonate aqueous solution. After completion of the reaction, 100 parts of water was added and acetone was distilled off under reduced pressure. 2 parts of activated carbon was added to the obtained reaction solution, and the mixture was stirred for 30 minutes and then filtered, 15% sodium chloride was added to the filtrate for salting out, and the precipitated solid was separated by filtration and dried. Disodium salt of coumarin compound 1
3.1 parts were obtained. (Maximum absorption wavelength: λmax 352 nm-
The result of analysis by liquid chromatography (the same applies hereinafter in pure water) (detected by absorption at 254 nm) The content of the target substance in the organic component was 96.4%.

Production Example 2 A reaction product liquid of cyanuric chloride and aniline-2,5-disulfonic acid obtained in the same manner as in Production Example 1 was heated to 30 ° C. to prepare 7-amino-3- (4-sulfophenyl). ) 33.5 parts of coumarin potassium salt dissolved in 300 parts of hot water
The mixture was added over 0 minutes and then reacted at 30 to 35 ° C. for 3 hours. During that time, 10% sodium carbonate aqueous solution was added to add p.
The H value was maintained at 4-5. After the reaction is completed, it is treated with activated carbon,
200 parts of isopropanol was added to the filtrate, and the precipitated solid was filtered and dried. 2 coumarin compounds 65.0
I got a part. (Maximum absorption wavelength 355 nm)

Production Example 3 19.0 parts of cyanuric chloride were dissolved in 100 parts of acetone,
Aqueous solution 90 kept at 0 to 5 ° C and containing 32.9 parts of 7-amino-3- (4-sulfophenyl) coumarin sodium salt
0 part was added dropwise over 1 hour. The reaction was continued for about 2 hours. During this period, the temperature was maintained at 5 to 10 ° C, and a 20% aqueous sodium hydroxide solution was added to maintain the pH value at 3 to 4. To the obtained gel-like primary reaction solution, 100 parts of an aqueous solution prepared by dissolving 11.4 parts of taurine with sodium hydroxide was added, gradually heated and reacted at 25 to 30 ° C. for about 3 hours. During this period, a 20% aqueous sodium hydroxide solution was added to adjust the pH value to 4
I kept it at 6. After the reaction was completed, N was treated in the same manner as in Production Example 1.
o. 49.3 parts of a coumarin compound of 3 was obtained. (Maximum absorption wavelength 354 nm)

Preparation Example 4 In Preparation Example 1, 2,5-disulfoaniline disodium was replaced by the same amount of 2,4-disulfoaniline disodium or 20.1 parts of sodium sulfanilate or N.
-Using 14.1 parts of methyl taurine sodium salt,
No. 4 compounds (maximum absorption wavelength 353n
m), No. Compound 5 (maximum absorption wavelength 354 nm) N
o. 6 compound (maximum absorption wavelength 351 nm) was obtained.

Production Example 5 19.0 parts of cyanuric chloride prepared according to Production Example 1 and 1-
Naphthol-3,6-disulfonate disodium 35.
The suspension obtained by the reaction with 0 part was reacted with 33.5 parts of 7-amino-3- (4-sulfophenyl) coumarin potassium salt in the same manner as in Production Example 2 to give No. 7 coumarin compound was obtained. (Maximum absorption wavelength: 353 nm)

Production Example 6 19.0 parts of cyanuric chloride prepared according to Production Example 1 and 2-
Naphthol, disodium 3,6-disulfonate 35.
The suspension obtained by the reaction with 0 parts is filtered at 10 ° C or lower,
Obtained press cake (including 42.5 parts of primary condensate)
Was dissolved in hot water at 30 ° C. to prepare 450 parts of solution. A solution prepared by dissolving 19.2 parts of 7-amino-3-phenylcoumarin in 150 parts of dimethylformamide was added dropwise thereto over 30 minutes, and then reacted at 35 to 40 ° C. for about 3 hours. The pH value was maintained at 4-6 during the dropping and during the reaction. After completion of the reaction, the same treatment as in Production Example 2 was performed and No. 8 coumarin compounds were obtained. (Maximum absorption wavelength 353 nm)

Production Example 7 No. 1 was obtained by synthesizing according to Production Examples 1 to 6. 9-No. 31
A coumarin-based compound is obtained. When these are used to fluorescently whiten the paper in accordance with Example 1 to be described later, a whitening effect to a slightly purple-white to slightly bluish-white hue is exhibited.

Example 1 Nos. Obtained in Production Examples 1-6. 1-No. A press cake containing 10 parts each of the coumarin-based compound of 7 was added to a surfactant (commercial name Pluronic L-46, which was composed of a copolymer of polyethylene glycol and polypropylene glycol).
Asahi Denka Kogyo Co., Ltd.) and an aqueous solution containing 25 parts of triethylene glycol and 15 parts of triethylene glycol to adjust the pH to 5.8 to obtain a chemically and physically stable aqueous liquid composition containing 10% of each coumarin compound. It was After being stored at 40 ° C. for 4 weeks, almost no change was observed.

Example 2 No. prepared in Example 1 20 parts of an aqueous liquid composition containing 1 to 800 parts of clay and 200 parts of ground calcium carbonate
Part, acrylic dispersant (KayacrylResinC
-220N, 3 parts by Nippon Kayaku Co., Ltd., phosphate esterified starch (MS-4600 by Nippon Shokuhin Kako Co., Ltd.) 50
Part, latex (styrene-butadiene type L-1622
Asahi Chemical Industry Co., Ltd. 120 parts, water resistant agent (Sumi
rezResin 636, manufactured by Sumitomo Chemical Co., Ltd. 4
For a mixture of parts, water is added to give a solids content of 55%
A coating solution prepared so as to have the above composition was prepared, applied on high-quality paper and dried to obtain a fluorescent whitened paper.

Comparative Example As a comparative example, the following formula (A) described in Example 1 of JP-A-6-294097.

[0046]

[Chemical 16]

10 parts of a coumarin compound represented by the following formula was ground with 2.5 parts of a surfactant consisting of a condensate of an alkylnaphthalene sulfonic acid and formaldehyde and 37.5 parts of water to contain 20% of an optical brightener. An aqueous dispersion was obtained. Using 10 parts of this dispersion, the same treatment as described above was carried out to obtain a fluorescent whitened fine paper. The test results obtained are shown in Table 1.

[0048]

[Table 1]                                       Table 1                                   Colorimetric Whiteness Hue No optical brightener 100 Example 2 (Compound of No. 1) 115 st Comparative Example (Compound of Formula (A)) 103 slightly greenish

The compound of the present invention containing a sulfone group has an excellent whitening property and, unlike a dispersion which tends to settle and become non-uniform, an aqueous solution which is easy to handle is obtained.

Example 3 50.0 parts of an aqueous liquid composition prepared in Example 1 (N
o. 2 compound 5.0 parts) and water 946.0 parts in an aqueous solution of anionic surface sizing agent (Polymaron 38).
2. After adding 4 parts of Arakawa Chemical Industry Co., Ltd., p of the solution
The H value is adjusted to 9.0 to obtain a size press coating solution. This solution was sent to a size press to color weak size paper having a Steckigt sizing degree of 7 seconds to obtain fluorescent whitening paper with good color uniformity and color value.

Example 4 0.05 part of the aqueous liquid composition prepared in Example (No.
An aqueous solution containing 50 parts of water and 0.005 parts of the compound of No. 5) was prepared.
2 parts (dry weight) of 5 ° SR) was added, and the mixture was stirred at room temperature for 10 minutes, and then 0.04 parts of rosin-based sizing agent (RF size 880L-50, manufactured by Misawa Ceramic Chemicals KK).
Was added. After further stirring for 5 minutes, 0.05 part of crystalline aluminum sulfate was added and stirred for 10 minutes. Then JISP
Papermaking and drying are performed according to the method described in -8209 (Method for preparing hand-skip paper for pulp test). The paper thus obtained showed a slightly bluish fluorescent whitening effect.

Example 5 (defluorescence treating agent) 2 parts of the whitening paper obtained in Example 3 were mixed with sodium metasilicate (0.2 parts).
08 parts, caustic soda 0.02 parts, hydrogen peroxide solution (35%
Product) 0.16 parts, and a deinking agent (Lipotol LH-100, manufactured by Nika Kagaku Co., Ltd.) 0.003 parts in an aqueous solution 66 parts, treated at a temperature of 50 ° C. for 3 hours, and then treated with JISP-8.
According to the method described in 209 (Preparation method for handmade paper for pulp test), papermaking and drying were performed to obtain a paper without fluorescent whitening property, and defluorescence treatment was completed.

[0053]

[Effects of the Invention] A fluorescent whitening method of paper and pulp using a specific water-soluble coumarin-based fluorescent whitening agent provides a fluorescent whitening effect with a high color value, and is easy to treat with an alkaline agent when recycling waste paper. In addition, since the fluorescent whitening agent can be removed, the influence on the environment is extremely small.

Continuation of the front page (56) Reference JP-A-9-143383 (JP, A) JP-A-8-74196 (JP, A) JP-A-49-53917 (JP, A) JP-A-6-194097 (JP , A) JP 49-61483 (JP, A) JP 48-37969 (JP, B1) JP 44-8885 (JP, B1) JP 43-9927 (JP, B1) (58) Fields investigated (Int.Cl. ⁷ , DB name) D21H 11/00-27/42 C09B 1/00-69/10 D06P 1/00-7/00

Claims (4)

(57) [Claims] 1. The following formula (1) in the form of a free acid: (In the formula (1), X represents a phenyl group which may have a sulfonic acid group, Y represents an alkoxy group having 1 to 5 carbon atoms, a hydroxyl group, a morpholino group, and a group represented by the following formula (2). Or [Chemical 2] (In the formula (2), R ₂ and R ₃ are each independently a hydrogen atom, an alkyl group having 1 to 5 carbon atoms which may have a substituent, or a carbon number 1 which may have a substituent. A group represented by the following formula (3): (In the formula (3), the aromatic ring A represents a benzene ring or a naphthalene ring which may have a substituent, B represents O, S or NH, and n represents an integer of 0 to 3), Z represents a hydrogen atom or a methyl group, and a water-soluble coumarin compound having one or more sulfonic acid groups in the molecule is used,
Fluorescent whitening method for paper and pulp 2. A paper using a coumarin compound in the formula (1) of claim 1, wherein Y is a 2-sulfoanilino group which may have a substituent or a taurino group which may have a substituent. Fluorescent brightening of pulp 3. A fluorescent whitening method for paper and pulp, which uses a coumarin compound in which Y is a phenoxy group or a naphthoxy group optionally having a substituent in the formula (1) of claim 1. 4. A method for defluorescence treatment of the paper or pulp obtained in any one of claims 1 to 3 with an alkaline agent.