JPH039239B2 - - Google Patents

Description

[Detailed description of the invention]

<Industrial Application Field> The present invention relates to an aqueous coating or impregnating composition that reduces discoloration over time and can effectively impart sterilizing and deodorizing properties to the object to be coated. <Prior Art> It is generally known that a composition consisting of L-ascorbic acid and an iron (2) compound has bactericidal and deodorizing properties. Examples of cases in which such properties are effectively utilized include, for example, the use of the former (sterilizing property) to sterilize processed foods and raw materials for salads that cannot be sterilized by heat, or to sterilize fresh foods and marine products, such as those that easily lose their freshness. It also sterilizes vegetables, fruits, meat, seafood, etc. to keep them fresh, preservative, and preserve them. Further, as an example of the use of the latter (deodorizing property), there is a use as a deodorizing agent in which the composition is attached to an activated carbon-containing carrier, or the composition itself is contained in paper cloth. However, the characteristics and uses of the above-mentioned composition were quickly proposed by the present inventor as a result of his research, and were published in a related publication in JP-A-59
−59604, JP-A-59-143576, JP-A-59-
No. 132937 and Japanese Unexamined Patent Publication No. 60-66756. <Problems to be Solved by the Invention> However, the composition containing the L-ascorbic acid and iron () compound may cause discoloration over time when it is applied to or impregnated onto a support.
Depending on the application, there were drawbacks such as a significant loss of commercial value. Therefore, in order to overcome this drawback, it has been considered to mix white pigments, but since the composition is strongly acidic, it has been difficult to cause aggregation or gelation. Another possibility is to coat or impregnate the composition and dry it, then apply a layer of white paint or the like to hide the discoloration. This is not practical because the top coat layer tends to fall off due to insufficient strength. Furthermore, the above-mentioned publication regarding the composition states that discoloration over time can be reduced by incorporating an appropriate amount of thiosulfate or dithionite into the composition, but depending on the type of support, In some cases, you may not expect much of an effect. From this perspective, the solution to the above problem has become a particularly urgent issue. The present invention has been made in view of the above points, and an object of the present invention is to provide an aqueous composition for coating or impregnation that reduces discoloration over time and has good sterilizing and deodorizing properties. <Means for Solving the Problems> As a result of intensive research in order to solve the above problems in the most rational and effective manner, the present inventor has found that the conventional L-
Numerous experiments have shown that when glyoxal is mixed into a composition containing ascorbic acid and an iron() compound, the resulting aqueous solution can be expected to reduce discoloration over time when coated or impregnated onto a support. We have completed the present invention. That is, the present invention provides ferrous sulfate, ferrous chloride,
An aqueous composition comprising at least one iron() compound selected from ferrous nitrate, L-ascorbic acid, and glyoxal, wherein the amount of glyoxal used in the aqueous composition is equal to or less than the iron 1 to 4000% by weight based on the total usage amount of the iron () compound and L-ascorbic acid, and the total usage amount of the iron () compound and L-ascorbic acid in the aqueous composition is It is an aqueous coating or impregnating composition consisting of 0.1 to 30% by weight. Therefore, the aqueous composition required in the present invention may be prepared by any one of the following methods. A mixed solid (including powder; the same applies hereinafter) containing L-ascorbic acid and an iron () compound and a solid glyoxal are simultaneously dissolved in water. A solid substance of glyoxal is dissolved in a mixed aqueous solution containing L-ascorbic acid and an iron () compound. A mixed aqueous solution containing L-ascorbic acid and an iron () compound and an aqueous solution of glyoxal are mixed. A mixture containing L-ascorbic acid and an iron compound (both solid substances) is dissolved in an aqueous solution of glyoxal, either separately or as a mixture. In the above aqueous composition, the content of glyoxal is preferably 1 to 4000% by weight (in terms of solid content; the same applies hereinafter) based on the total amount of L-ascorbic acid and iron () compound used. It is essential that there be. When the amount used is less than 1% by weight, the effect of reducing discoloration over time when a support is coated or impregnated with the obtained aqueous composition becomes insufficient. In addition, if the amount used exceeds the upper limit of 4000% by weight, the above-mentioned drawbacks will be resolved, but if the concentration of the two-component composition (mixture containing L-ascorbic acid + iron () compound) is too low, the sterilizing and deodorizing properties will be impaired. This makes it difficult to apply and is not practical. The liquid concentration of the aqueous composition at this time is 0.3~
50% by weight, preferably 1 to 35% by weight, but the total content of L-ascorbic acid and iron() compound in the liquid is 0.1 to 30% by weight, preferably 1.0 to 35% by weight.
It is important to keep the content within 20% by weight. This range is the best range for imparting the desired sterilizing and deodorizing properties to the support after coating or impregnation. If this content is less than 0.1% by weight,
Due to too little content of the components (L-ascorbic acid + iron () compound), it is not possible to have both the desired bactericidal and deodorizing properties. In addition, its content is 30
If it exceeds % by weight, the above-mentioned drawbacks will be solved, but it will be difficult to maintain a predetermined concentration (0.3 to 50% by weight) of the aqueous composition, making it unsuitable for treatments such as coating. As described above, the present invention can most effectively achieve the desired object by mixing the components constituting the aqueous composition in a certain mixing ratio (range) as described above. . As the support for coating the above water-based composition, paper,
Non-woven fabrics, synthetic resin films, and for impregnation, paper, non-woven fabrics, etc. may be optionally used. <Function> As described above, the present invention produces iron () by mixing a certain amount of glyoxal (solid content) with respect to the total usage amount (solid content equivalent) of a composition containing L-ascorbic acid and iron () compound. The compound effectively removes the source of malodor by forming a complex with the source (component) of malodor, and at the same time exhibits bactericidal properties by generating superoxide radicals (O ₂ ^- ). Composition (aqueous solution)
It reduces the degree of discoloration over time when a support is coated or impregnated with it. <Effects of the Invention> The present invention exhibits the following unique effects. The present invention provides a composition comprising L-ascorbic acid and at least one iron compound selected from ferrous sulfate, ferrous chloride, and ferrous nitrate. Since the composition is a mixture of a certain amount of glyoxal (solid content) with respect to the total usage amount (solid content equivalent) of L-ascorbic acid and the above-mentioned iron () compound, the aqueous solution is coated or impregnated onto the support. The degree of discoloration over time is reduced, and the decline in product value due to discoloration can be minimized. Further, as described above, the iron () compound that comes into contact with the malodor source forms a complex with the malodor source (component), while the superoxide radical (O ^{2 -} ) and imparts bactericidal properties. Furthermore, while the deodorizing properties of compositions containing L-ascorbic acid and iron () compounds have traditionally been excellent against nitrogen-based malodors (components) such as ammonia and amines, The deodorizing power against sulfur-based malodors (components) such as
However, the aqueous composition of the present invention contains glyoxal, which itself has deodorizing properties, and its deodorizing effect is Although it is not as good as the composition containing L-ascorbic acid and the iron compound in terms of nitrogen-based bad odors (components) such as ammonia and amines, it is less effective in terms of sulfur-based bad odors (components) such as hydrogen sulfide and mercaptan. , said L
- Has superior efficacy to compositions containing ascorbic acid and said iron() compound. Therefore, if glyoxal is used, the deodorizing effect against sulfur-based malodors (components) such as hydrogen sulfide and mercaptans will be enhanced, and the imbalance in deodorizing effectiveness against nitrogen-based malodors (components) and sulfur-based malodors (components) mentioned above will be enhanced. is corrected and equalized, giving it stronger odor-preventing properties. Therefore, the present invention can simultaneously impart sterilization and deodorization properties to the support while reducing the degree of discoloration over time when the coating liquid is applied or impregnated onto the support. ) and for maintaining freshness, etc., and its application fields are wide and its practical benefits are remarkable. <Example> Preparation of aqueous solution (a) Solution A: 10 g of the former and 10 g of the latter so that the total amount of L-ascorbic acid and ferrous sulfate used was 100 g.
Weigh out 90 g of L-ascorbic acid and ferrous sulfur into a 1000 ml flask, add 300 g of water, and stir until the total amount of L-ascorbic acid and ferrous sulfur in the aqueous solution (solid content equivalent; the same applies hereinafter) is 25% by weight. A composition (aqueous solution) prepared to have a concentration of % was obtained. (b) Solution B Dilute 100g of Solution A prepared in (a) above with 62.3g of water so that the total amount of L-ascorbic acid and ferrous sulfate in the aqueous solution is 15.4% by weight. A prepared composition (aqueous solution) was obtained. (c) Solution C 100g of Solution A prepared in (a) above and 62.5g of glyoxal 40% by weight solution were mixed and stirred, and the total usage amount of L-ascorbic acid and ferrous sulfate in the aqueous solution was 15.4% by weight. A composition (aqueous solution) was obtained in which the amount of glyoxal used was 15.4% by weight. (d) Solution D Add 1.25 g of solid sodium thiosulfate to 100 g of Solution A prepared in (a) above, stir, and add 61.1 g.
diluted with water, the total amount of L-ascorbic acid and ferrous sulfate used in the aqueous solution is 15.4% by weight, and the amount of sodium thiosulfate relative to the total amount of L-ascorbic acid and ferrous sulfate used is A composition (aqueous solution) prepared such that the amount used was 5% by weight was obtained. (e) Solution E Add 25 g of a 5% by weight aqueous solution of locust bean gum to 100 g of Solution A prepared in (a) above and stir.The total amount of L-ascorbic acid and ferrous sulfate accounted for in the aqueous solution. is 20.0% by weight, L-
A composition (aqueous solution) was obtained in which the amount of locust bean gum used was 5% by weight relative to the total amount of ascorbic acid and ferrous sulfate used. (e)′ E′ Solution Add 100 g of a 5% by weight aqueous solution of locust bean gum to 100 g of A solution prepared in (a) above and stir to calculate the total amount of L-ascorbic acid and ferrous sulfate in the aqueous solution. Usage amount is 12.5% by weight, L
- A composition (aqueous solution) was obtained in which the amount of locust bean gum used was 20% by weight relative to the total amount of ascorbic acid and ferrous sulfate used. (f) Solution F To 100 g of Solution A prepared in (a) above, 62.5 g of glyoxal 40% by weight solution and 31.3 g of 4% by weight solution of locust bean gum were added and stirred. The total amount of monoferrous used is 12.9% by weight, the amount of glyoxal is 12.9% by weight, and the amount of locust bean gum used is 5% by weight relative to the total amount of L-ascorbic acid and ferrous sulfate. A prepared composition (aqueous solution) was obtained. (f)'F' Solution To 100 g of Solution A prepared in (a) above, 62.5 g of glyoxal 40% by weight solution and 125 g of 4% by weight solution of locust bean gum were added and stirred, and L-ascorbic acid and sulfuric acid occupied in the aqueous solution. The total usage amount of ferrous iron is 8.7% by weight, the usage amount of glyoxal is 8.7% by weight, and the usage amount of locust bean gum is 20% by weight based on the total usage amount of L-ascorbic acid and ferrous sulfate. A composition (aqueous solution) was obtained. Discoloration test over time (a) The above liquids A and C were applied by rod coating on commercially available paper (conventional method), and the resulting liquid A and C coated paper were heated at 20°C and a relative humidity of 65%. When the sample was stored in a cool environment and the change in hue over time was measured using a color difference meter, the results shown in Table 1 and FIG. 1 were obtained.
The coating amount of the liquid is 6.1 g/m ² for liquid A, which is the total solid content of L-ascorbic acid and ferrous sulfate.
The B liquid was 6.0 g/m ² . In addition, the values in Table 1 are the color difference ΔE between the liquid coated paper and uncoated paper,
ΔE is ΔE=√(−′) ² +(−′) ² +(−′) ² L, a, b: Measured values for the liquid coated paper L′, a′, b′: Uncoated paper is given as a measurement value for . (b) Apply the above liquids B, C, D, E, and F to commercially available paperboard (using the conventional method), and test the results of each liquid-coated paper over time in the same manner as in (a) above. When the hue change was measured, the results shown in Table 2 and FIG. 2 were obtained. The coating amount of the liquid is 4.7g/B liquid based on the total solid content of L-ascorbic acid and ferrous sulfate.
m ² , 5.2 g/m ² for liquid C, 5.5 g/m ² for liquid D, 4.0 g/m ² for liquid E, and 2.0 m ² for liquid F. Further, the values in Table 2 are the color difference ΔE between the liquid-coated paper and the uncoated paper, and ΔE is as shown in (a) above.

【table】

【table】

[Table] As is clear from Table 1, Table 2, Figures 1 and 2, an aqueous solution containing L-ascorbic acid and ferrous sulfate, or an aqueous solution containing L-ascorbic acid and ferrous sulfate and vegetable gum It can be seen that the degree of discoloration over time when a composition (aqueous solution) containing glyoxal mixed with an aqueous solution containing glyoxal is applied to western paper or paperboard is significantly reduced compared to when glyoxal is not added. Deodorization Test The following deodorization test was conducted on the A-coated paper, C-liquid coated paper, and F-liquid coated paper obtained in (a) of the above temporal discoloration test, and the results shown in Table 3 were obtained. (Ammonia odor control test) (a) Smell bag for environmental analysis (manufactured by Gascro Kogyo Co., Ltd.,
Air is injected into Capacity 3), and an appropriate amount of ammonia vapor is injected into this to uniformly disperse it, and then the ammonia concentration is measured via a detection tube (manufactured by Kitazawa Sangyo Co., Ltd.). (b) Cut the specimen into 5 mm x 30 mm to obtain a certain number (30 pieces) of the specimen. After that, the entire amount of the test piece (B) is placed in the ammonia-containing bag (A), a silicone rubber stopper is applied, and the bag is left for 1 hour, after which the ammonia concentration in the bag is measured via a detection tube. . (Hydrogen sulfide deodorization test) (a) Smell bag for environmental analysis (manufactured by Gascro Industries,
Air is injected into Capacity 3), an appropriate amount of hydrogen sulfide vapor is injected into it, and after uniformly dispersing it, the hydrogen sulfide concentration is measured via a detection tube (manufactured by Kitazawa Sangyo Co., Ltd.). (b) Cut the specimen into 5 mm x 30 mm pieces to obtain a certain number of specimens (150 pieces). After that, the test piece was placed in the hydrogen sulfide-containing bag (a).
After adding the entire amount of (b) and applying a silicone rubber stopper, leave it for 7 hours and measure the hydrogen sulfide concentration inside the bag via a detection tube.

[Table] As is clear from Table 3, the coating amount (L-ascorbic acid and ferrous sulfate-containing aqueous solution) and the composition (aqueous solution) in which this aqueous solution is mixed with glyoxal When coated paper is coated on a support (paper) so that the total solid content of iron is the same and treated in an odor-containing atmosphere by a prescribed method, the odor prevention rate is the same for ammonia. Both liquids and liquids show an equally high deodorization rate, but
Regarding hydrogen sulfide, the solution containing glyoxal has a significantly higher deodorization rate than the solution containing no glyoxal. In other words, by using glyoxal in combination, the original bactericidal and deodorizing effects of L-ascorbic acid and iron () compounds are not inhibited in any way, and the imbalance in deodorizing power with respect to the type of malodorous components is corrected and balanced. It can be seen that stronger deodorizing properties are imparted. Furthermore, even when a vegetable gum substance is mixed, the effect of glyoxal is not inhibited in any way. Liquid property test The liquid viscosity and water retention of the above liquids A, E, E', C, F, and F' were measured, and the results shown in Table 4 were obtained.

【table】

[Table] That is, when a vegetable gum substance is mixed into an aqueous solution containing L-ascorbic acid and ferrous sulfate, the liquid viscosity and water holding capacity of the liquid can be increased;
Even when glyoxal is mixed in the liquid, the desired increase in liquid viscosity and water retention can be achieved by mixing a vegetable gum substance.

[Brief explanation of drawings]

FIGS. 1 and 2 are characteristic diagrams showing the relationship between color difference and number of days over time.

Claims (1)

[Claims] 1. An aqueous composition comprising at least one iron compound selected from ferrous sulfate, ferrous chloride, and ferrous nitrate, L-ascorbic acid, and glyoxal, the aqueous composition comprising: The amount of glyoxal used in the composition is the same as that of the iron() compound and L-
1 to 4000% by weight based on the total amount used with ascorbic acid, and the above iron () in the aqueous composition.
An aqueous composition for coating or impregnation, characterized in that the total amount of the compound and L-ascorbic acid used is 0.1 to 30% by weight based on the aqueous composition.