JPH0319536B2 - - Google Patents

Description

[Detailed description of the invention]

``Object of the Invention'' The present invention relates to a near-ultraviolet sensing material capable of detecting the integrated illuminance of near-ultraviolet light having a wavelength of 2000 Å to 4000 Å. "Industrial Application Fields and Prior Art" In recent years, the harmful effects of excessive sunbathing have been pointed out, and it is said that repeated exposure to ultraviolet rays, especially those with short wavelengths, can cause skin damage. Further, ultraviolet rays are used in various industrial fields, such as ultraviolet germicidal lamps and ultraviolet drying paints, and optimal irradiation or prevention of excessive irradiation is required for both process control and safety and health reasons.
Conventionally, to measure ultraviolet irradiation intensity, integrated ultraviolet irradiance, etc., technologies such as photocurrent conversion and electrolysis were used, which required electrical operation and measurement, resulting in large and expensive equipment. . The present inventors have discovered that a specific composition changes its color when irradiated with near ultraviolet rays and increases the color density based on stoichiometric theory, and provides a simple measuring tool using this composition as a near ultraviolet detection material. As a result of repeated research aimed at this purpose, we have arrived at the present invention. This application consists of two inventions; the first invention is a solution made of the above composition, and the second invention is a sheet-like product using the solution. In order to use the solution composition of the first invention as a detection material in a simple measurement tool, it can be placed in a shallow container made of quartz or the like with low ultraviolet absorption. The second invention of the present application is a product in which the solution composition described above is coated on a sheet, or the essential components of the first invention are laminated and coated on a sheet as a single product without mixing, and finished as a label or the like. The integrated illuminance of ultraviolet rays can be easily measured based on the color change and color density change. The specific composition referred to in the present invention is one that contains polyvinyl chloride with a low degree of polymerization and a specific colored dye or colorless dye as essential components and exhibits the above-mentioned effects. Also, the term "laminate coating on a sheet as a single product" means that the layers of each of the above-mentioned single components are combined on the sheet. Since these achieve the same purpose, they may be collectively referred to as a composition in the following description. ``Problems to be Solved by the Invention'' It is known that polyvinyl chloride causes changes in color tone and color density that are favorable to physical energy such as heat, light, and shearing force. Especially those with low degree of polymerization,
A single polymer that is not copolymerized with vinyl acetate or the like is likely to cause the above color change. However, these color changes cannot be used as detection materials. This is because the amount of change is too small. Therefore, we focused on free radicals and hydrogen chloride generated during the photodecomposition process of polyvinyl chloride. From the results of numerous experiments, it was discovered that there are colored dyes or colorless dyes that undergo stoichiometrically accurate color changes under the influence of trace amounts of hydrogen chloride or free radicals generated during the decomposition process, and that low polymerization with either of these dyes is possible. It has been found that a material suitable for measuring near-ultraviolet integrated illuminance can be obtained by coexisting with polyvinyl chloride. According to the first invention of the present application, there is provided a solution composition comprising polyvinyl chloride with a low degree of polymerization and a colored dye or a colorless dye as essential components, the composition having a wavelength of 2000 Å to 4000 Å.
The second invention of the present application provides a near-ultraviolet sensing material capable of detecting the integrated illuminance of near-ultraviolet rays by causing the colored dye or colorless dye to undergo a clear color change and color density change when irradiated with near-ultraviolet rays of 500 nm. A sheet material coated with a composition of polyvinyl chloride of a high degree of polymerization and a colored dye or a colorless dye, or a laminated material coated with a composition of polyvinyl chloride of a low degree of polymerization and a colored dye or a colorless dye, respectively, as a single product. A near-ultraviolet sensing material is a sheet-like material that is capable of detecting the cumulative illuminance of near-ultraviolet light by causing the colored dye or colorless dye to undergo a clear color change and color density change when irradiated with near-ultraviolet light with a wavelength of 2000 Å to 4000 Å. provided. "Structure of the invention" Below, near ultraviolet rays, polyvinyl chloride, colored dyes,
The first invention will be explained with a distinction made to colorless dyes, and the second invention will be referred to. Generally, ultraviolet light sources that are used for various purposes include sunlight, carbon arc light, mercury lamp light, and xenon lamp light, and none of them include wavelengths of 2000 Å or less, so the detection range is limited to wavelengths. Made to fit over 2000Å. 4000 again
Å or more is the visible region, and since the storage conditions are disadvantageous in practice for substances that cause color changes and color density changes (hereinafter referred to as color changes) due to visible light, in the present invention, irradiation light in the wavelength range of 2000 Å to 4000 Å is used. The integrated illuminance can now be calculated using . As mentioned above, a single vinyl chloride polymer that is not copolymerized with low polymerization degree polyvinyl chloride, vinyl acetate, etc. has a wavelength of 2000.
When irradiated with near ultraviolet light of Å to 4000 Å, it photodecomposes to produce hydrogen chloride, albeit in a small amount, and free radicals are generated during the decomposition process. However, in visible light, these can be ignored. Among these polyvinyl chlorides with a low degree of polymerization, the present invention uses polyvinyl chloride with an average degree of polymerization of 250.
It is preferable to select and use ~600. If the average degree of polymerization is 600 or more, the stability of polyvinyl chloride increases and sensitivity tends to deteriorate. If the average degree of polymerization is less than 250, the polymer itself may contain free hydrogen chloride, etc. This is because it is unsuitable as a raw material. In addition, in the second invention of the present application, such polyvinyl chloride also has the disadvantage of poor physical properties when a composition or a single product thereof is applied to a sheet to form a coating film. The most preferred range is an average degree of polymerization of 300 to 400. As the colored dye to be combined with such polyvinyl chloride, the present invention utilizes a dye that causes a color change when combined with polyvinyl chloride and is irradiated with near ultraviolet rays, and therefore does not include a dye that does not cause a color change. Furthermore, it is not preferable to use a dye that strongly changes color when irradiated with light having a wavelength other than 2000 Å to 4000 Å, especially visible light. In the present invention, the following colored dyes, generally called indicators, which change color when exposed to acid or alkali, are commonly used. Indicators whose blue-purple color changes to a border color; crystal violet, blue-purple or purple, or indicators whose blue color changes to yellow; promophenol blue, bromocresol purple, tetrapromophenol blue, bromocresol green, bromothymol blue, yellow to red Thymol Blue, Tropeolin OO, Methyl Yellow, Methyl Orange, Methyl Red, Neutral Red, Cresol Red, Indicator that changes from yellow to blue; Indigo Carmine, Indicator that changes from red to yellow; Bromophenol Red Do, Phenol Red, Tropeolin OOO,
Alizarin Yellow R, an indicator that changes from red to blue; Congo Red, an indicator that changes from red to colorless; phenolphthalein, an indicator that changes from blue to colorless; thymolphthalein, etc. In addition, when using these colored dyes, if necessary, a very small amount of alkali is added to the dyes and used as an alkaline side color. There is no problem in using these colored dyes in combination, and when coating a sheet, different colors can be applied in several areas. Next, the colorless dye that is combined with polyvinyl chloride becomes colored when it is combined with polyvinyl chloride and irradiated with near ultraviolet rays, causing a change in color density. Colorless dyes that do not have this function are not included. do not have. Also, colorless dyes that are colored only by irradiation with light having wavelengths other than 2000 Å to 4000 Å, particularly visible light, are not preferred. Preferred examples of colorless dyes that satisfy the above requirements include leuco dyes conventionally used in pressure-sensitive recording paper, heat-sensitive recording paper, etc., and the following can be used. Triphenylmethane phthalide series, fluoran series, phenothiazine series, indolyl phthalide series, lyuco auramine series, spiropyran series, triphenylmethane series, triazene series, naphtholactam series, azomethine series, benzopyran series, spirophthalanxanthene series , hydroxyphthalane type, rhodamine lactam type, etc. All of these are colorless, but after color development in the composition of the present invention, various colors are imparted depending on the colorless dye of each series, and the color density increases in accordance with the irradiation time. These may be used in combination if necessary, and when the composition is applied to a sheet, it is also possible to apply different colors in several areas. The above-mentioned leuco dye is an electron-donating substance, and coloration occurs due to interaction with free radicals generated during the photodecomposition process of polyvinyl chloride or action with hydrogen chloride that remains as a result, and the color density is stoichiometrically Since the photochemical changes in polyvinyl chloride are accurately amplified, the integrated illuminance can be accurately detected. Since most of this type of dye is oil-soluble, it is dissolved in an organic solvent together with polyvinyl chloride and placed in a plastic container, quartz container, etc. that has low ultraviolet absorption, and is used as the detection material of the first invention of the present application. In that case, a low concentration solution is used, and the change in concentration is determined using a densitometer and the integrated illuminance is calculated. In order to obtain a visually detectable material according to the second invention of the present application, a colored dye or a colorless dye is coated as a single substance on a substrate such as paper, film, glass plate, metal foil, etc., and then the same is applied on the dried surface. Apply a single component polyvinyl chloride solution and dry. The order of coating does not matter. Most leuco dyes are oil-soluble, so they are allowed to coexist in an organic solvent solution of polyvinyl chloride, and water-soluble and alcohol-soluble dyes, such as the indicators exemplified as colored dyes, coexist in an emulsion solution of polyvinyl chloride. It is also a preferred embodiment of the present invention to coat the mixture on a base material and use it as a sensing material after drying. To obtain the integrated illuminance, compare it with a standard color tone and standard color density table prepared in advance for each light source so that the integrated illuminance can be obtained. The blending ratio of colored dyes or colorless dyes is 0.2 to 4, respectively, to polyvinyl chloride.
It can be used in a range of 1 to 2% by weight, preferably 1 to 2% by weight. "Effects of the Invention" As explained above, the present invention provides that polyvinyl chloride with a low degree of polymerization can be used within a range where polyvinyl chloride with a wavelength of 2000 Å to 4000 Å practically does not cause color change or color density change when irradiated with near ultraviolet rays with a wavelength of 2000 Å to 4000 Å. is used as one component, and the other component, colored dye or colorless dye, amplifies the photochemical changes in polyvinyl chloride by irradiating it with near ultraviolet rays, causing a remarkable color change and color density change, and the integration is based on this. Since the illuminance can be determined, it is possible to accurately determine the integrated illuminance within the irradiation range where no color change of the polyvinyl chloride itself is observed visually or with a densitometer. If necessary, stabilizers for polyvinyl chloride, antioxidants, ultraviolet absorbers, sensitizers, etc. may be mixed and used within the range that does not impair the effects of the present invention. Example 1 10g of polyvinyl chloride (KR-400, manufactured by Mitsubishi Monsanto) with a degree of polymerization of 350, 45g of methyl ethyl ketone
A solution consisting of 45 g of toluene, 0.2 g of leuco dye (PSD-V, manufactured by Nisso Chemical Co., Ltd.) was further diluted 5 times with methyl ethyl ketone, packed in a quartz container with a depth of 5 mm, and exposed to near ultraviolet light of 2537 Å. (Mercury lamp light) was irradiated. The intensity of the irradiated light is 0.50mw/
It was warm in ^cm2 . After an integrated illuminance of 90 mw·min/cm ² or an irradiation time of 180 minutes, the color became red, and the red density-irradiation time curve had extremely good reproducibility. Furthermore, the polyvinyl chloride solution obtained by removing the leuco dye from the detection solution had no change in color density after 180 minutes of irradiation.
The same was true for solutions containing only leuco dye. Example 2 The undiluted polyvinyl chloride and leuco dye solution used in Example 1 was directly coated on cast coated paper (manufactured by Sanyo Kokusaku Pulp, basis weight 157 g/m ² ) using Meyer Bar #22. The process was repeated 3 times and coated. The coating weight was 3 g/m ² . The obtained detection material was exposed to 3650 Å of mercury lamp light (3650 Å intensity 0.4 mw/cm ² ).
Fade-o-meter arc lamp light (3650Å intensity
2.6mw/cm ² ), sunlight (midsummer clear and sunny temperature 32℃,
PM12:00~PM3:00, 3650Å intensity 1.0mw/ ^cm2 )
was irradiated. The changes in red color density obtained at that time were as shown in the table below. The numerical values indicate the values measured by a Macbeth densitometer after irradiation.

[Table] As mentioned above, all three types of light sources emit near-ultraviolet light with a wavelength of 3650 Å, and the table above shows that the red density increases with the irradiation time. It can also be seen that the concentration increases as the intensity of the irradiated light increases. In this example, the red density reached its maximum value after a certain period of time depending on the type of irradiation light, and did not increase thereafter. At the same time, the paper coated only with polyvinyl chloride (without the leuco dye from the paint in this example) showed no signs of irradiation even after irradiation for 180 minutes.
The measured concentration of all samples was 0.09, and no change occurred. In addition, the change in color density after irradiation of the cast-coated paper coated with only the leuco dye was slight and did not affect the test results shown in the above table. Furthermore, even when the sample of this example was irradiated with visible light or infrared light that does not include near-ultraviolet light, no change in color density was observed unless it was for an extremely long time. As another test, the sensing material used in this example was coated with the solution containing only polyvinyl chloride of this example once, and then repeatedly coated with the solution containing the leuco dye of this example twice. Results similar to those in the table were obtained. Example 3 1 g of cresol red and 100 ml of ethyl alcohol
g and add 0.1 ml of 10% KOH to give a yellow solution. Immediately after immersing Toyo Roshi No. 3 in this solution, pull it up, drop the excess liquid, and dry it.
500 polyvinyl chloride (KR-600, manufactured by Mitsubishi Monsanto) 10g, methyl ethyl ketone 45g, toluene
A solution consisting of 45 g was coated once with a Meyer bar #22 and dried to provide a sensing material. The coating weight was 4 g/m ² . This product has a yellow finish, but changes color to red when exposed to near ultraviolet rays. Color density changes showed good reproducibility with respect to irradiation time. When only cresol red was applied, almost no color change was observed due to near ultraviolet irradiation.

Claims (1)

[Scope of Claims] 1. A solution composition containing polyvinyl chloride with a low degree of polymerization and a colored dye or a colorless dye as essential components, wherein said colored dye or colorless dye is irradiated with near ultraviolet light with a wavelength of 2000 Å to 4000 Å. 1. A near-ultraviolet sensing material that is capable of detecting the integrated illuminance of near-ultraviolet rays by causing clear color changes and color density changes. 2 The average degree of polymerization of polyvinyl chloride is 250 to 600
A near-ultraviolet sensing material according to claim 1. 3. The near-ultraviolet sensing material according to claim 1 or 2, wherein the colored dye is an indicator that causes a color change in the presence of acid or alkali. 4. The near-ultraviolet sensing material according to claim 1 or 2, wherein the colorless dye is an electron-donating leuco dye. 5 A sheet-like article coated with a composition of polyvinyl chloride with a low degree of polymerization and a colored dye or a colorless dye, or a laminated coating in which the polyvinyl chloride with a low degree of polymerization and a colored dye or a colorless dye are each applied as a single product. If it is a processed sheet material, the wavelength is 2000 Å or more.
A near-ultraviolet sensing material characterized in that the integrated illuminance of near-ultraviolet rays can be detected by causing the colored dye or colorless dye to undergo a clear color change and color density change when irradiated with near-ultraviolet rays at 4000 Å. 6 The average degree of polymerization of polyvinyl chloride is 250 to 600
The near-ultraviolet sensing material according to claim 5. 7. The near-ultraviolet sensing material according to claim 5 or 6, wherein the colored dye is an indicator that causes a color change in the presence of acid or alkali. 8. The near-ultraviolet sensing material according to claim 5 or 6, wherein the colorless dye is an electron-donating leuco dye.