JPH0254867B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a method for fluorescent whitening of organic materials using a novel stilbene derivative, and in particular provides an effective method for fluorescent whitening in the surface treatment of paper. be. [Prior Art] A large number of derivatives of 4,4'-bistriazinylaminostilbene-2,2'-disulfonic acid have been proposed for use in the fluorescent whitening of organic materials, and many have been proposed for their use. Many types are in practical use. Recently, it has become popular to whiten paper by adding a fluorescent brightener to the paper surface treatment liquid.
At that time, there is a strong demand for a material that is unlikely to cause concentration quenching even when used at high concentrations and that provides a high degree of whiteness. Formulated as a fluorescent brightener most suitable for such purposes A stilbene derivative (compound A) in which R is a phenoxy group (JP-A-48-18314, JP-A-Sho
49-31983), and a compound in which R is a p-carboxyphenoxy group (compound B) is also described in the same document. [Problems to be Solved by the Invention] The present invention provides a fluorescent whitening agent that provides a higher degree of whiteness than these known fluorescent brightening agents when used for surface treatment of organic materials such as paper. It is intended to provide a method. [Means for solving the problem] The inventors, etc. use the general formula (In the formula, X ₁ and X ₂ are the same or jointly 2, 4
-disulfoanilino group or 2,5-disulfoanilino group, and R ₁ and R ₂ are the same or a combination of lower alkyl groups. It has been found that the stilbene derivative or its salt represented by ) does not easily cause concentration quenching even when used at high concentrations, and is an extremely suitable compound for high whitening of paper by surface treatment. The stilbene derivative represented by the general formula () has two molecules of cyanuric chloride and aniline-2,4-
Disulfonic acid or/and aniline-2,5-
2 molecule ratio of disulfonic acid or their salts,
1 molecule ratio and formula of 4,4'-diaminostilbene-2,2'-disulfonic acid or its salt

【Formula】also/and

It can be produced by reacting two molecules of hydroxybenzoic acid ester represented by the formula. That is, aniline-2,4-disulfonic acid or aniline-2,5-disulfonic acid or a salt thereof was added to cyanuric chloride at 20°C.
4,4'-diaminostilbene-2,2'-
Disulfonic acid or its salt is reacted at a temperature range of 25° to 80°C, and finally, hydroxybenzoic acid ester is reacted at a temperature of 80°C or higher. Aniline-disulfonic acid and 4,4'-diaminostilbene-
Although it is preferable that the amount of 2,2'-disulfonic acid used is not in excess of cyanuric chloride, better results can be obtained by using a slightly excessive amount of hydroxybenzoic acid ester. In this reaction, cyanuric chloride may be used after being dissolved in an organic solvent such as acetone, but an organic solvent may not be used and only water may be used as a medium. For example, the product can be precipitated and taken out by adding salt to the reaction-completed solution, but since the stilbene derivative represented by the general formula () has extremely high solubility in water, the yield is low when taking it out by salting out. It's bad. Therefore, it is advantageous for these stilbene derivatives to be commercialized as a concentrated solution by removing the common salt produced by the reaction and concentrating the water by an appropriate method. The hydroxybenzoic acid ester used as a raw material for the stilbene derivative represented by the general formula () tends to be slightly hydrolyzed when heated in the reaction solution before the reaction or after bonding to the triazine nucleus. Among the stilbene derivatives, in the formula ()

[Formula] Also is/and

[Formula] is

Although a trace amount of the stilbene derivative represented by the formula (2) may be present, this trace amount of the by-product does not significantly impair the whitening power of the stilbene derivative represented by the formula (2). The stilbene derivative represented by the general formula () is extremely effective for use in fluorescent whitening by surface treatment of paper. This surface treatment may be size press coating or pigment coating according to conventional methods. In size press processing, starch is used as a sizing agent.
Modified starch or oxidized starch alone or a mixture thereof with polyvinyl alcohol or carboxymethyl cellulose can be used. In pigment coating, for example, clay, kaolin, aluminum hydroxide, or calcium carbonate is used as a filler, and as a sizing agent, a mixture of starch, modified starch, or oxidized starch with resin latex, or a mixture of casein and resin latex is used. Mixtures may be used or resin latexes may be used alone. In the surface treatment of these papers, the fluorescent whitening ability of the stilbene derivative represented by the general formula () is enhanced by coexisting with an alkaline substance. As the alkaline substance, for example, an inorganic base such as sodium hydroxide is effective, but an organic amine such as tri- or dialkanolamine is particularly effective. Since the stilbene derivative represented by the general formula () is highly water-soluble, it is inefficient to use it in the so-called internal addition method in which it is added to pulp slurry before papermaking in the papermaking process, or in the dip dyeing method or continuous dyeing of brocade paper cloth. However, it has very good compatibility with the resin liquid used for resin processing of cotton cloth, and does not easily cause precipitation even when mixed with the resin liquid, so it is extremely suitable for one-bath resin processing of cotton cloth. It also dyes nylon well and exhibits an excellent whitening effect. Tables 1 and 2 show that the stilbene derivative represented by the general formula () has superior fluorescent whitening ability compared to known compounds A and B.
Shown in the table. Table 1 is a table comparing the whiteness (fluorescence value) of the size press coated paper produced in Example 1 and the two types of size press coated papers produced in Comparative Example 1. The numerical values listed are the fluorescence values of each sample when the fluorescence value of a standard fluorescent plate is set as 100 using a Yagi type microfluorophotometer (Table 2 is the same).

[Table] Table 2 is a table comparing the whiteness (fluorescence value) of the size press coated paper produced in Example 2 and the two types of size press coated papers produced in Comparative Example 2.
Even if the composition other than the fluorescent brightener is the same, if the fluorescent brightener contains triethanolamine, all three types of fluorescent brighteners have the same fluorescent whitening ability. However, even in this case, this shows that the stilbene derivative represented by the general formula () has the best fluorescent whitening ability.

[Table] Alkanolamines are effective not only to increase the fluorescent whitening ability of stilbene derivatives, but also to increase the stability of concentrated solutions prepared by adding them, and urea, ethylene glycol, polyethylene glycol, etc. Effective for increasing the stability of concentrated solutions. Production example 1 90ml of water and cyanuric chloride in the four-necked flask from step 1.
20.0 g of ice 140 g and 1 drop of nonionic surfactant were added and stirred rapidly for 30 minutes. Next, a solution of 29.9 g of monosodium salt of aniline-2,5-disulfonic acid and 5.8 g of anhydrous sodium carbonate dissolved in 80 ml of water was added dropwise over 30 minutes at a temperature of 0 to 5°C.
Further, stirring was continued for 1 hour and 30 minutes while maintaining the same temperature and gradually adding an aqueous sodium carbonate solution to maintain weak acidity. The liquid temperature was raised to 25°C, an aqueous sodium carbonate solution was added to adjust the pH to 6.0, and 19.3 g of 4,4'-diaminostilbene-2,2'-disulfonic acid and 5.8 g of anhydrous sodium carbonate were dissolved in 120 ml of water. The solution was added, further 5.5 g of anhydrous sodium carbonate was added, the temperature was raised, and stirring was continued for 1 hour at a temperature of 55 to 60°C. Next, 6.2 g of anhydrous sodium carbonate and 19.8 g of methyl p-hydroxybenzoate (1.2 times the theoretical amount) were added, and stirring and refluxing was continued for 2 hours. After cooling, trace amounts of insoluble matter were removed by filtration, and the filtrate (total volume: 600 ml) was divided into two equal parts. Add 80 g of common salt to one half of the filtrate, leave it overnight, collect the precipitate by filtration, dry and crush it to obtain 4,4'-
Bis[2-(2,5-disulfoanilino)-4-
(p-methoxycarbonylphenoxy)-1,3,
5-triazin-6-ylamino]stilbene-
48g of pale yellow powder of hexasodium 2,2'-disulfonate was obtained (salt content 28.6%, 0.01g/
Absorption value of aqueous solution at 345 nm: 0.264, 4,4'-
90% yield from diaminostilbene-2,2'-disulfonic acid). In addition, the other half of the filtrate is treated with a pressure filtration device using a semi-permeable membrane to remove most of the salt in the filtrate along with a portion of the water, and combine it with the washing water of the device.
400 ml of a stilbene derivative aqueous solution was obtained. This aqueous solution was concentrated under reduced pressure to approximately 120 ml, and 80%
14.5 g of triethanolamine was added and further concentrated to obtain 116.2 g of a concentrated solution of the above stilbene derivative as a light brown, slightly viscous liquid. this solution
The absorbance value at 345 nm of a solution of 0.03 g of 1 dissolved in water was 0.356. (Yield 98 from 4,4'-diaminostilbene-2,2'-disulfonic acid
%) This aqueous solution was stable with no precipitates even after long-term storage. Example 1 Size press (all starch) 4,4'-bis[2-(2,
22.5 g of hexasodium 5-disulfoanilino)-4-(p-methoxycarbonylphenoxy)-triazin-6-ylamino]stilbene-2,2'-disulfonate was dissolved in 100 ml of pure water. Add 10 g of oxidized starch powder (manufactured by Oji National Co., Ltd., "Oji Ace A") to 80 g of pure water, heat and dissolve while stirring to form the above stilbene derivative aqueous solution.
10.0 ml was added, and pure water was further added to prepare a coating solution with a total amount of 100 g. This coating liquid was applied to non-fluorescent white high-quality paper using wire rod No. 9, and dried at a temperature of 90°C for 1 minute to make size press paper with a coating weight of 2 g/m ² .
After cooling, the fluorescence intensity was measured using a Yagi microfluorometer. The measured values are shown in Table 1. Comparative Example 1 According to Production Example 1, 4,4′-bis[2-(2,5
-disulfoanilino)-4-phenoxy-1,3,
5-triazin-6-ylamino]stilbene-
A powder of hexasodium 2,2'-disulfonate (compound A) was prepared (0.01 g/aqueous solution).
Absorbance value at 345nm 0.281). Similarly, 4,4'-bis[2-(2,5-disulfoanilino)-4-(p-carboxyphenoxy)-
A powder of octanodium 1,3,5-triazin-6-ylamino]stilbene-2,2'-disulfonate (compound B) was synthesized (absorbance value at 345 nm of 0.01 g/aqueous solution: 0.276). Stilbene derivative powder in Example 1 22.5
21.1 g of the above-mentioned compound A powder and 21.5 g of compound B powder were used in place of 1 g, and the other operations were carried out in the same manner as in Example 1 to prepare two types of size press coated papers. When these two types of size press coated paper and the size press coated paper obtained in Example 1 were compared under sunlight, the size press coated paper of Example 1 was the whitest and most beautiful. The fluorescence values of the size press coated papers using Compound A and Compound B are shown in Table 1. Example 2 (Size Press (All Starch)) The 4,4'-bis[2-(2,
5-disulfoanilino)-4-(p-methoxycarbonylphenoxy)-1,3,5-triazine-
50.0 g of a concentrated solution of hexasodium 6-ylamino]stilbene-2,2'-disulfonate was dissolved in pure water to prepare 100 ml of an aqueous solution of a stilbene derivative. Stilbene derivative aqueous solution used in Example 1
10.0ml of the above stilbene derivative aqueous solution
Size press coated paper was prepared in the same manner as in Example 1 using 10.0 ml. Although the concentration of the stilbene derivative in the coating liquid applied to this size press coated paper was the same as that in the coating liquid in Example 1, this size press coated paper was exposed to sunlight in Example 1. Noticeably whiter than size press coated paper. The fluorescence values of this size press coated paper are shown in Table 2. Comparative Example 2 A concentrated solution of Compound A and Compound B (0.03 g/aqueous solution at 345 nm absorbance of both was 0.356) was prepared according to Production Example 1. Two types of size press coated papers were prepared in the same manner as in Example 2 using these concentrated solutions instead of the concentrated solutions used in Example 2. When these size press coated papers and the size press coated paper obtained in Example 2 were compared under sunlight, the size press coated paper of Example 2 was the whitest and most beautiful. The fluorescence values of the size press coated papers using Compound A and Compound B are listed in Table 2. Example 3 10.0 g of oxidized starch (Oji Ace C, manufactured by Oji National Co., Ltd.) was mixed with 66.0 g of pure water and dissolved by heating. Sodium pyrophosphate (1st grade reagent) in 80ml of pure water
0.5 g was dissolved, and then 100.0 g of clay ("Katsukoyama K Clay" manufactured by Katsukoyama Mining Co., Ltd.) was added and mixed well. Next, add the entire amount of the above oxidized starch solution and mix well, then add 20.0 g of resin latex (manufactured by Asahi Kasei Corporation, "DOW1924" (concentration 50%)), mix well, and then mix well using a homomixer. To 138.0 g of this mixed solution, 20.0 ml of the stilbene derivative aqueous solution used in Example 2 was added and mixed well with a homomixer while warming to a temperature of approximately 40°C to prepare a coating solution. .14 on non-fluorescent white wood-free paper and dried for 1 minute at 90°C to produce pigment-coated paper with a coating weight of 12 g/ ^m2.This paper is highly sensitive under sunlight. It exhibited beautiful whiteness. Example 4 Aniline-2,4 was used instead of monosodium aniline-2,5-disulfonate used in Production Example 1.
- using monosodium disulfonate 4,
4′-bis[2-(2,4-disulfoanilino)-4
-(p-methoxycarbonylphenoxy)-1,
Hexasodium 3,5-triazin-6-ylamino]stilbene-2,2'-disulfonate was synthesized, and its concentrated solution (0.03 g/
An aqueous solution with an absorbance of 0.356 at 345 nm was prepared. Dissolve 50.0g of this concentrated solution in pure water and make 100.0ml.
Pigment coated paper was prepared in the same manner as in Example 3 using 20.0 ml of the sample. This paper exhibited almost the same beautiful whiteness as the paper of Example 3 under sunlight. Example 5 A reaction was carried out using 21.6 g of ethyl p-hydroxybenzoate instead of methyl p-hydroxybenzoate used in Production Example 1 to produce 4,4'-bis[2-(2,5-disulfoanilino). -4-(p-ethoxycarbonylphenoxy)-1,3,5-triazin-6-ylamino]stilbene-2,
Hexasodium 2'-disulfonate was synthesized and a concentrated solution thereof was prepared according to the production example. The absorbance value at 345 nm of this concentrated solution (0.03 g/1 aqueous solution) was 0.356. Dilute 5.0g of this concentrated solution with pure water to 2500.0ml,
Mix 10.0ml of this with 290ml of water, adjust the pH to 4.0 with acetic acid, heat it, add 10.0g of nylon jersey cloth at a temperature of 60℃, and heat it to 90℃ for 15 minutes while stirring.
The staining was carried out at 90°C for 30 minutes. Take out the cloth, wash it with water, wring it out with a mangle, and then dry it at a temperature of 60℃.
Dry for 20 minutes. When observed under sunlight, this cloth exhibited an extremely beautiful white color. Example 6 Concentrated solution of stilbene derivative obtained in Production Example 1
4.0g was dissolved in pure water to make 100ml (liquid A). In addition, a 10% solution of glyoxal resin (Sumitex Resin NS-2 manufactured by Sumitomo Chemical Co., Ltd.) 20.0
g and 6.0 g of a 3% solution of a resin curing catalyst (Sumitex Accelerator Mix well 50ml of liquid B and 2.2m of chemically bleached cotton broadcloth (width 8cm, length 45cm).
Padded at room temperature for 1 minute. The compression rate was 80% with 1 dip and 1 nip. 60
Wash with water for 15 minutes at a temperature of 180 °C, then at a temperature of 180 °C
Cure for 30 seconds and add surfactant aqueous solution (2
g/) at a temperature of 40°C for 2 minutes, then washed with water and dried. When this cloth was observed under sunlight, it had a beautiful white color. Example 7 Using methyl m-hydroxybenzoate in place of methyl p-hydroxybenzoate in Production Example 1, 4,4'-bis[2-(2,5-disulfoanilino)-4-(m-methoxycarbonyl) phenoxy)-1,3,5-triazin-6-ylamino]
Hexasodium stilbene-2,2'-disulfonate was synthesized and a concentrated solution thereof was prepared according to the production example. 0.03g of this concentrated solution/345nm of aqueous solution
The absorbance value was 0.356. Cotton broadcloth was treated with resin in the same manner as in Example 6, using the above concentrated solution in place of the stilbene derivative concentrated solution used in Example 6. This cloth had almost the same beautiful whiteness as the cloth of Example 6. (Effect of the invention) As described above, according to the present invention, organic materials,
In particular, it has a remarkable fluorescent whitening effect in the surface treatment of paper, so it is of great industrial benefit.

Claims (1)

[Claims] 1. General formula as a fluorescent whitening agent (In the formula, X ₁ and X ₂ are the same or different 2, 4
- a sulfoanilino group or a 2,5-disulfoanilino group, and R ₁ and R ₂ are the same or different lower alkyl groups) or a salt thereof. Photobrightening method.