JP3304348B2 - High-molecular-weight thiourea compound with fluorescence - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a novel thiourea compound having a high fluorescence and its use as a fluorescent labeling agent in papermaking coating.

[0002]

2. Description of the Related Art A fluorescent substance has a characteristic that it can be accurately and easily quantified even in a small amount by measuring its fluorescence. There is a fluorescent tracer method as its industrial use. The fluorescent tracer method is a method in which a fluorescent substance in an amount proportional to the target substance is added simultaneously with the target substance, the concentration of the fluorescent substance is measured, and the amount of the target substance is calculated from this.
Known fluorescent tracers include 2-naphthalenesulfonic acid, Acid Yellow 7, sulfonated stilbenyl naphthazole, and fluorescein (Japanese Patent Publication No. 6-1143).
No. 7, JP-A-3-185341). There is also a method in which a polymer substance for the purpose of quantification is labeled with a fluorescent substance so that the concentration of the substance can be quantified by a fluorescence method. As an example, a method of introducing a fluorescent substance into a polyacrylamide, acrylic acid, or maleic acid-based polymer is known (Japanese Patent Publication No. 5-63591, Japanese Patent Application Laid-Open No. Hei 7-109587).
However, a fluorescent high molecular weight thiourea compound having a main chain of polyallylamine or polyethyleneimine is not known.

In the production of general printing paper, starch, modified starch (oxidized starch, starch derivative, etc.), polyvinyl alcohol (hereinafter, “polyvinyl alcohol” is abbreviated as “PVA”), polyacrylamide (hereinafter referred to as “polyvinyl amide”) are used as surface strength measures. Hereinafter, “polyacrylamide” is abbreviated as “PAM”). In order to perform these coatings rationally, it is necessary to measure and control the concentration of the coating liquid and the amount applied to the paper. As a method for measuring the concentration of starch and modified starch and the amount of starch coated on paper, there is an enzyme method for decomposing into glucose using an iodine method and glucoamylase, and quantifying the glucose to convert the amount of starch. The PVA measurement method includes an iodine method. As a method of measuring PAM, a method of measuring the amount of nitrogen by the Kjeldahl method and converting the amount of PAM from the value is generally used.

[0004] However, these methods have the disadvantage that the measurement takes a long time. Therefore, a fluorescent tracer method has been proposed as a method for simplifying the measurement of the concentration of the coating liquid and the amount of coating on the paper.

[0005] However, the fluorescent tracer method has the characteristic that it can be measured in a short time, but it is difficult to use starch, PVA and PAM.
It does not directly measure the behavior of the coating agent since it does not measure the concentration of the coating agent itself. In particular, when measuring the coating amount of paper, the reflected fluorescence of the paper is measured, and the coating amount is calculated from the fluorescence intensity.
A high molecular compound such as a coating material and a low molecular compound fluorescent substance generally used as a fluorescent tracer often differ greatly in behavior on paper, for example, in permeability to paper.

[0006]

SUMMARY OF THE INVENTION Under such circumstances, the present invention provides a novel fluorescent polymer compound, and a small amount of the compound is added to a coating solution to form a coating material for printing paper. The purpose of the present invention is to use the novel fluorescent labeling agent that can easily, accurately and quickly measure the concentration and application amount of a liquid.

[0007]

Means for Solving the Problems The present inventors have conducted intensive studies to achieve the above object, and as a result, as a substance having a novel fluorescence, it is represented by the following formulas [1] and [2]. A high molecular weight thiourea compound having a molecular weight of 5,000 to 500,000 , and a labeling of a coating agent such as starch, modified starch, PVA, PAM, etc. with a polymeric fluorescent substance to achieve the object, Based on this finding, the present invention has been completed.

[0008]

Embedded image

[0009]

Embedded image

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention is represented by novel formulas [1] and [2], which are useful for controlling the coating conditions of a papermaking coating agent.
And a fluorescent high molecular weight thiourea compound having a molecular weight of 5,000 to 500,000 .

The compound represented by the formula [1] of the present invention is easily produced by reacting the compound represented by the formula [3] with the compound represented by the formula [4] (fluorescein isothiocyanate). be able to.

[0012]

Embedded image

[0013]

Embedded image An example of a method for producing the polymer thiourea compound represented by the formula [1] of the present invention includes a compound represented by the formula [3]:
1 to 10 equivalents of the compound represented by the formula [4] in a polar solvent such as water, methanol, ethanol or an aqueous base solution such as sodium hydroxide, potassium hydroxide or potassium carbonate at a temperature of 5 to 50 ° C. And the reaction is performed for 10 minutes to 2 hours to obtain a high molecular weight thiourea compound represented by the formula [1].
Specific examples of the compound represented by the formula [3] include polyallylamine.

The compound represented by the formula [2] of the present invention can be easily produced by reacting the compound represented by the formula [5] with the compound represented by the formula [6].

[0015]

Embedded image As an example of the method for producing the polymer thiourea compound represented by the formula [2] of the present invention, the compound represented by the formula [5]
1 to 10 equivalents of the compound represented by the formula [4] in a polar solvent such as water, methanol, ethanol or an aqueous base solution such as sodium hydroxide, potassium hydroxide or potassium carbonate at a temperature of 5 to 50 ° C. And the reaction is carried out for 10 minutes to 2 hours to obtain a high molecular weight thiourea compound represented by the formula [2].
Specific examples of the compound represented by the formula [5] include a compound obtained by the above-mentioned method including polyethyleneimine.
The high-molecular-weight thiourea compound represented by [1] or [2] can be dialyzed using a suitable dialysis membrane or purified into a highly purified product by column chromatography.

The fluorescent polymer thiourea compound of the present invention comprises
Since it is a polymer compound, starch, PV
Since it behaves similarly to coating agents such as A and PAM,
The object of the present invention can be achieved.

When the fluorescent thiourea compound having a molecular weight of 5,000 to 500,000 of the present invention is used by adding it to a coating solution as a fluorescent labeling agent, it can be accurately measured by fluorescence analysis with a minimum amount of addition. Therefore, the amount of fluorescein isothiocyanate introduced into polyallylamine or polyethyleneimine is preferably as high as possible. The molecular weight of polyallylamine and polyethyleneimine is
The molecular weight is preferably from 5,000 to 500,000. When used as a fluorescent labeling agent in a coating solution, it is desirable to select the molecular weight of polyallylamine or the like in consideration of the molecular weight of the coating agent to be mixed.

[0018]

EXAMPLES The present invention will be described in detail below with reference to examples, but the present invention is not limited to the following examples.

[Synthesis Example 1] <Production of high molecular thiourea compound represented by formula [1]>
In a conical flask, add 156 mg of fluorescein isothiocyanate and 100 ml of ethanol to dissolve,
200 ml of 0.4 mM aqueous solution of polyallylamine (molecular weight 100,000)
And 700 ml of water were added and stirred for 30 minutes. Next, the supernatant was collected by centrifugation, the pH was adjusted to 7 with hydrochloric acid, and dialyzed with a dialysis membrane in distilled water for 2 days. Next, it was dried under reduced pressure and weighed. The yield was 0.45 g. When the fluorescence characteristics of this polymer compound were measured, the maximum excitation wavelength was 490 n
m, the maximum fluorescence wavelength was 520 nm, and the fluorescence intensity per 1 mg / l of the polymer compound was 16,700. When the composition of this polymer compound was measured by nuclear magnetic resonance, the molar ratio of polyallylamine to fluorescein isothiocyanate was 12/35.

[Synthesis Example 2] <Production of high molecular weight thiourea compound represented by formula [2]>
200 ml of an aqueous solution of 0.4 mM polyethyleneimine (molecular weight: about 50,000) and 700 ml of water were added to a 200 ml Erlenmeyer flask, and a 200 mM ethanol solution of 2 mM fluorescein thioisocyanate was added.
Then, the mixture was stirred for 2 hours. Then, the reaction solution was dialyzed with a dialysis membrane in distilled water for 2 days. Next, this was dried under reduced pressure and weighed. The yield was 1.3 g. When the fluorescence characteristics of this polymer compound were measured, the maximum excitation wavelength was 490
nm, maximum fluorescence wavelength is 520 nm, polymer compound 1 mg / l
The fluorescence intensity per hit was 21,700. When the composition of this polymer compound was measured by nuclear magnetic resonance, the molar ratio of polyethyleneimine to fluorescein isothiocyanate was 12/43.

The melting point, infrared absorption spectrum, nuclear magnetic resonance spectrum and fluorescence spectrum of the compound obtained in each of the synthesis examples were measured by the following methods. 1. The compounds obtained in Synthesis Example 2 are shown in Table 2. Infrared absorption spectrum: Measured by a KBr method using Magna-IR850 manufactured by Nicolet Corporation. Nuclear magnetic resonance spectrum: Measured by a Fourier transform method using QE-PLUS manufactured by Oxford. Fluorescence spectrum: Spectrofluorimeter R manufactured by Shimadzu Corporation
Measured with F-5300

[0022]

[Table 1]

[0023]

[Table 2]

[Example 1] <Calculation of concentration by fluorescence measurement> Polyacrylamide 1k
g, the fluorescent polymer thiourea compound prepared in Synthesis Example 1 was added at a ratio of 200 mg, and after stirring well, 10 to 0.5%
The concentration was adjusted and fluorescence analysis was performed. Excitation wavelength 490nm,
The fluorescence intensity at a fluorescence wavelength of 515 nm was measured and compared with the coating solution concentration. The result is shown in FIG.

[0025]

FIG. From FIG. 1, it can be seen that there is a good correlation between the coating solution concentration and the fluorescence intensity (R ² = 0.9).
99) was obtained. Therefore, it was found that the concentration of the coating solution could be controlled by adding the fluorescent polymer thiourea compound.

[Example 2] <Test for measuring coating amount of printing paper> Polyacrylamide 1k
g to the fluorescent polymer thiourea prepared in Example 1.
The mixture was added at a rate of 200 mg, adjusted to a predetermined concentration, and coated.
A cloth solution was used. Put this on the F side of newsprint base paper
Using a coater, the coating amount is 0.2 to 0.5 g / m ^TwoRange
Was applied. After coating, calendered and used for newspaper printing
I got the paper.

[0027] Newsprint paper of each coating amount was analyzed by the Kjeldahl method, and the coating amount of polyacrylamide was calculated. In addition, the excitation wavelength of each newsprint paper is 490 nm and the fluorescence wavelength is 5
The fluorescence intensity at 15 nm was measured, and the correlation with the applied amount of polyacrylamide was determined. The result is shown in FIG.

[0028]

FIG. 2 From FIG. 2, a good correlation (R ² = 0.99) was obtained between the amount of polyacrylamide applied to newsprint and the fluorescence intensity of newsprint. Therefore, it was found that by preparing a calibration curve in advance, the application amount of newsprint can be controlled.

[0029]

The fluorescent high molecular thiourea compound of the present invention is a polymer having an extremely high fluorescence intensity. By adding a small amount of this to a coating liquid for paper, for example, the concentration of the coating liquid in gate roll coating can be improved. And the amount of paper applied can be measured very easily, accurately and quickly, and as a result, it is easy to adjust the optimal concentration of the coating liquid,
Coating conditions can be set rationally.

────────────────────────────────────────────────── ─── Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) C08G 73/00-73/26 G08F 2/00-246/00 CAPPLUS (STN) REGISTRY (STN)

Claims (3)

(57) [Claims] 1. A high molecular weight thiourea compound represented by the formula [1] and having a molecular weight of 5,000 to 500,000. Embedded image 2. A high molecular weight thiourea compound represented by the formula [2] and having a molecular weight of 5,000 to 500,000. Embedded image 3. The molecular weight 5 according to claim 1 or 2.
A fluorescent labeling agent consisting of 1,000 to 500,000 high molecular weight thiourea compounds.