JPH10279822A - Deodorant water-absorbent resin - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a deodorant water-absorbent resin excellent in safety for a human body and in deodorizing capability by incorporating a water-insoluble or hardly water-soluble tetravalent-metal phosphate into the same. SOLUTION: Either of the following deodorants, each having a very low toxicity to a human body and being a water-insoluble or hardly water-soluble tetravalent-metal phosphate, is used: a deodorant (A) represented by the formula: Ha Mb Oc (PO4 )d .nH2 O [M is a tetravalent metal; a to d are each positive (provided that c may be 0) and satisfy the relation: a+4b=2c+3d; and n is 0 or a positive number] and a deodorant (B) represented by the formula: Ha Ab Bc Md Oe (PO4 )f .nH2 O (A is a monovalent metal; B is a divalent metal; M is a tetravalent metal; and a to e and n are each 0 or a positive number, provided that b and c are not simultaneously 0, that d and f are each a positive number, and that a to f satisfy the relation: a+b+2c+4d=2e+3f). The water-absorbent resin is a copolymer which has a crystal structure or a crosslinked structure and swells by quickly absorbing water when brought into contact with water.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a deodorant water-absorbent resin containing a specific deodorant, and in particular, diapers and sanitary napkins used for treating urine and feces of infants, bedridden elderly people, sick people, etc. It is useful as a water-absorbent resin which can be used as a sanitary material and can deodorize the odor caused by urination or feces during long-term contact with the human body or after use.

[0002]

2. Description of the Related Art In recent years, the demand for a comfortable life is rapidly increasing. As one of them, the function of deodorizing has received a great deal of attention, and it has been attempted to impart deodorizing property to a water-absorbent resin which is widely used for sanitary products and the like. Normally, a sanitary product is a laminated molded product in which a water absorbent resin is sandwiched between non-woven fabrics and the like, and it excels in water absorption.
It is desired to reduce the smell of hydrogen sulfide in the excrement. Activated carbon, zeolite and the like have been known as deodorants for a long time, and those in which primary amine of aromatic genus is impregnated in activated carbon, those in which pH of activated carbon is adjusted, and the like have been proposed. Further, a combination of an iron compound and ascorbic acid and a polymer compound having an amino group or a sulfone group are also known as deodorants. However, since it is hard to say that they are sufficiently safe for the human body, they cannot be included in the water-absorbent resin in a large amount, or the deodorizing property against a malodorous gas is not sufficient. The resin has a problem that the deodorizing property is insufficient.

[0003]

DISCLOSURE OF THE INVENTION The present invention is intended to provide a deodorant water-absorbent resin which is excellent in safety for the human body and is excellent in deodorant property.

[0004]

[A is a monovalent metal, B is a divalent metal, M is a tetravalent metal, a, b, c, e and n are 0 or a positive number, and b and c are both 0. None, d and f are positive numbers, and a, b, c, d, e, and f satisfy the equation (a+b+2c+4d=2e+3f). ]

[0005]

[A is a monovalent metal, B is a divalent metal, M is a tetravalent metal, a, b, c, e and n are 0 or a positive number, and b and c are both 0. None, d and f are positive numbers, and a, b, c, d, e, and f satisfy the equation (a+b+2c+4d=2e+3f). ]

(Deodorant a) Deodorant a is a tetravalent metal phosphate represented by the above general formula [1] which is insoluble or sparingly soluble in water and is a compound having hydrogen. This deodorant (i) exhibits excellent deodorant properties against amine compounds such as trimethylamine, triethylamine and pyridine, and basic gases such as ammonia. Preferred specific examples of M in the above formula [1] include zirconium, titanium, tin, cerium, hafnium and the like, and zirconium and titanium are more preferred. The respective coefficients of a, b, c and d in the preferable deodorant a are the following numbers. a=1, b=1, c=1, d=1 a=1, b=2, c=0, d=3 a=2, b=1, c=0, d=2

The tetravalent metal phosphate represented by a=1, b=1, c=1, d=1 is a compound that is easily obtained as amorphous fine particles having an average particle size of 1 μm or less, and a=1. , B=2,
The tetravalent metal phosphate represented by c=0, d=3 is a NASICON type crystalline compound or an amorphous compound, and a=2, b
=1, c=0, d=2, the tetravalent metal phosphate is
A crystalline compound or an amorphous compound having a layered structure such as an α-type crystal which is a monohydrate, a β-type crystal which is an anhydrous salt, and a γ-type crystal which is a dihydrate. Particularly preferred tetravalent metal phosphate represented by the above formula [1] has the largest crystal interlayer distance and a high deodorizing rate, and therefore a=2, b=1, c=
It is a γ-type crystal having a coefficient of 0 and d=2.

The following compounds are preferred specific examples of the deodorant a. _{HTiO (PO 4) HZrO (PO} 4) HZr 2 (PO 4) 3 · H 2 O HTi 2 (PO 4) 3 · H 2 O HSn 2 (PO 4) 3 · 3H 2 O H 2 Zr (PO 4) ₂ H ₂ Ti(PO ₄ ) ₂・2H ₂ OH ₂ Sn(PO ₄ ) ₂・H ₂ O

(Deodorant II) The deodorant II is a tetravalent metal phosphate represented by the above general formula [2] which is insoluble or hardly soluble in water, and is a monovalent metal and/or a divalent metal. It is a compound having a valent metal. This deodorant (b) exhibits excellent deodorizing properties against sulfur-containing gases such as hydrogen sulfide and methyl mercaptan, and lower fatty acids such as acetic acid, valeric acid and butyric acid. Specific preferred examples of M in the above formula [2] include zirconium, titanium, tin, cerium, hafnium and the like, and zirconium and titanium are more preferred. As a preferred specific example of the monovalent or divalent metal in the deodorant (b),
Lithium, sodium, potassium, cesium, magnesium, calcium, strontium, barium, copper,
Examples include iron, zinc, nickel, manganese, and cobalt.
Among these, sodium, potassium, copper, zinc and manganese are preferable. A in the preferred deodorant B,
Each coefficient of b, c, d, e and f is a number satisfying the following formula (provided that a, b and c may be 0, and b and c
Are not both 0). a+b+c=1, d=1, e=1, f=1 a+b+c=1, d=2, e=0, f=3 a+b+c=2, d=1, e=0, f=2 The above formula [2] The tetravalent metal phosphate represented by
A part or all of hydrogen in the compound represented by
Compounds having a structure in which a valent metal is substituted, particularly preferred are compounds of the formula (a+b+c=2, d=1, e=0,
It is a crystalline compound having a γ-type layered structure having a coefficient satisfying f=2 (provided that a, b and c may be 0 and b and c are not both 0).

Since the tetravalent metal phosphate represented by the above formula [1] has a cation exchange property, the deodorant b can be converted to 1 by the ion exchange with hydrogen in the above formula [1]. A valent metal and/or a divalent metal can be easily supported on the tetravalent metal phosphate represented by the above formula [1], and specifically, the tetravalent metal phosphorus represented by the above formula [1]. Acid salts with monovalent metals and/
Alternatively, it can be easily supported by bringing it into contact with an aqueous solution containing a salt or hydroxide of a divalent metal. Two
When one or more kinds of metals are supported, it may be carried by one-time ion exchange using an aqueous solution containing two or more kinds of metals, or by plural times of ion exchange. When a monovalent metal and a divalent metal are supported, ion exchange can be efficiently performed by first supporting the monovalent metal and then supporting the divalent metal. The supported amount of the monovalent metal and/or the divalent metal is at most 1 within the ion exchange capacity of the tetravalent metal phosphate represented by the above formula [1].
It can be freely controlled up to 00% if desired,
In order to exert sufficient deodorizing property on sulfur-containing gas, lower fatty acid, etc., the supported amount of the above metal should be 25% of the ion exchange capacity (1.6 mg equivalent in the case of α-zirconium phosphate). /G) or more, more preferably 50% (3.2 mg equivalent/g in the case of α-zirconium phosphate)
The above is better. On the other hand, the deodorant B having hydrogen ions has a deodorizing property with respect to a basic gas. Therefore, when it is desired to simultaneously deodorize the basic gas together with the sulfur-containing gas, the lower fatty acid, etc. The amount can also be appropriately adjusted within the range of less than 100% of the ion exchange capacity.

The deodorizers a and b have a function of reproducing the deodorizing ability against a malodorous gas, particularly a basic malodorous gas such as ammonia gas and aliphatic amine gas, by irradiating with ultraviolet rays. That is, after the deodorant is once used until it loses its deodorizing ability, it is irradiated with ultraviolet rays to reuse the deodorant, or deodorizing is performed under the irradiation of ultraviolet rays so that the life of the deodorant is reduced. Can be extended. The regenerating function of the deodorizing ability by ultraviolet irradiation can be exerted more strongly in the deodorant a than in the deodorant b. It is presumed that this is because deodorant a and deodorant b have a photocatalytic function, and this photocatalytic function can be exerted more strongly in deodorant a than deodorant b. Since ultraviolet rays are also contained in sunlight and fluorescent light, they can naturally be regenerated with these lights.

All of the deodorants in the present invention are usually obtained in the form of powder and preferably have an average particle size of 0.01 to 20 μm, more preferably 0.01 to 10 μm, still more preferably 0. It is from 01 to 5 μm. Average particle size 0.0
If it is less than 1 μm, there is a problem in that it easily reaggregates and is difficult to handle, which is not preferable. On the other hand, if it is larger than 20 μm, it is difficult to disperse it uniformly in the resin, and it is difficult to adhere it to the surface of the water-absorbent resin.

○ Water-Absorbing Resin The water-absorbing resin in the present invention is not limited, and the polymer having a crystal structure or a cross-linking structure is capable of quickly absorbing and swelling when it comes into contact with water. As long as it is composed of a polymer, preferred specific examples are poly(meth)acrylate, polyvinyl alcohol, polyethylene oxide, polysulfonate, poly(meth)acrylamide, carboxymethyl cellulose, vinyl alcohol/acrylate copolymer. , A synthetic polymer compound containing an acrylate/acrylamide copolymer as a main component, and a natural polymer such as agar, konjak mannan, alginate, or carrageen, to which the above synthetic polymer compound is grafted. The water absorbent resin may be a mixture of two or more kinds. The preferred amount of the deodorant added to the water absorbent resin is 1 from the viewpoint of effect and economy.
0.0001 per 00 parts by weight (hereinafter simply referred to as "part")
To 5 parts, and more preferably 0.05 to 2 parts.
If the amount of the deodorant added is less than 0.0001 part, the deodorant effect is not sufficiently exerted, and if it is more than 5 parts, the improvement of the effect depending on the ratio of addition is not recognized and it is economical. In addition to the above problems, there is a possibility that the original characteristics of the water absorbing resin may be impaired in terms of the water absorbing speed of the water absorbing resin and the dry feel.

As a method of adding a deodorant to the water absorbent resin,
There is a method of joining with pressure, a method of adhering with a binder, a method of simply mixing, etc. In all cases, sufficient deodorant properties can be exhibited, but economical efficiency, workability, quick effect etc. are considered If so, it is preferable to add it in the surface treatment step of the water absorbing resin as follows.

That is, a small amount of water is added to the water-absorbent resin powder (a resin containing 3% or more of water in advance can be used as it is) to improve the adhesiveness of the resin surface. Add an appropriate amount of the deodorant of the present invention and other additives as necessary, and stir well. At this time, it is also possible to heat-dry at the same time as or after stirring.

When adding a deodorant to the water-absorbent resin powder,
Add a multifunctional cross-linking agent and optionally other additives,
It can be heated with stirring. A preferred polyfunctional crosslinking agent is a compound having two or more functional groups capable of reacting with a carboxylic acid group, a hydroxyl group, a sulfonic acid group, an amino group or the like in a water absorbent resin, and as a preferred specific example, a diglycidyl ether type There are compounds, polyvalent metal salts, haloepoxy compounds, aldehyde compounds, isocyanate compounds and the like.

O Applications The deodorant water-absorbent resin of the present invention can be used for sanitary products such as disposable diapers and sanitary products by sandwiching a deodorant between nonwoven fabrics and the like. In addition, it is useful in the conventionally known fields of use of water-absorbing resins that utilize the water-absorbing or water-retaining properties of water-absorbing resins, such as animal cooling agents for ice pillows, hydration sheets for food, water-absorbing sheets for fresh meat, and the like.

[0018]

EXAMPLES AND COMPARATIVE EXAMPLES The present invention will be specifically described below with reference to Examples and Comparative Examples. (Examples 1 to 10 and Comparative Examples 1 to 4) Various deodorants [A] to [J] containing the specific deodorant of the present invention in a predetermined weight ratio (Table 1 below. Mixing in Table 1 below) Ratios are weight ratios), or conventional deodorants for comparison [a] ~
[D] (Table 2 below) was added to the water absorbent resin as follows. That is, 100 parts of sodium acrylate-based water-absorbing resin powder having a water absorption capacity of about 300 times that of distilled water is added to 2 parts.
Add 0 parts of water and stir well to remove the deodorant [A] ~
One part of the deodorant selected from [J] or the deodorants [a] to [d] was added. Then, it was dried at 120° C. for about 2 hours to obtain a deodorant water-absorbent resin of the present invention (Tables 3 and 5 below). As a result of examining the water absorption capacity of each resin obtained above, it was about 300 times, no decrease in water absorption capacity was observed, and discoloration of the water absorption resin with time was not observed.

Examples 11 to 20 and Comparative Examples 5 to 8 The same as Examples 1 to 10 except that 0.5 part by weight of a polyethylene glycol diglycidiether compound was added as a crosslinking agent together with the deodorant. The deodorant water-absorbent resin of the present invention was obtained (Tables 4 and 5 below). As a result of examining the water absorption capacity of each resin obtained above, it was about 300 times, no decrease in water absorption capacity was observed, and discoloration of the water absorption resin with time was not observed.

(Deodorant test) With respect to each sample obtained in Examples and Comparative Examples, the deodorant property against each of the three gases shown in Table 6 below was evaluated as follows. That is, the sample was placed in a Tedlar bag (1 liter) and sealed, then gas was injected, and 24 hours after the injection of gas was completed, the gas concentration in the Tedlar bag was detected by a detector tube (manufactured by Gastec Co., Ltd.).
Or gas chromatography (made by Shimadzu Corporation)
It was measured by. The initial gas concentration when the gas was injected into the Tedlar bag is shown in Table 5 below. However, when the gas generation source was a liquid, the sample was brought into contact with the gas after being left to stand for about 2 hours for complete gasification. The method for measuring the gas concentration was appropriately selected depending on the type of gas. Sulfur malodorous gas was used for gas chromatography, and other gases were used for detector tubes. In addition, due to the limitation of measuring equipment, 100p
When the concentration was higher than pm, gas chromatography was performed by appropriately diluting to a measurable concentration, and the obtained measured value was converted to the original concentration according to the dilution ratio. The results of the deodorant test obtained as described above are shown in Tables 7 to 9 below (ND in the table means that it is below the detection limit).

[0021]

[Table 1]

[0022]

[Table 2]

*) Product name of Kuraray Co., Ltd.: Kuraray Coal 3GC-H

[0024]

[Table 3]

[0025]

[Table 4]

[0026]

[Table 5]

[0027]

[Table 6]

[0028]

[Table 7]

[0029]

[Table 8]

[0030]

[Table 9]

From the results of Examples 1 to 3 in Table 7 and Examples 11 to 13 in Table 8 above, the water-absorbent resin containing the deodorant a is excellent in deodorizing property against basic gas such as ammonia. I understand. From the results of Examples 4 to 6 in Table 7 and Examples 14 to 16 in Table 8 above, the water-absorbent resin containing the deodorant B has a deodorant property with respect to a sulfur-containing gas such as hydrogen sulfide and methyl mercaptan. It can be seen that it is particularly excellent and has excellent deodorizing property even with respect to basic gas such as ammonia. Examples 7 to 10 in Table 7 above and Examples 17 to 10 in Table 8 above
From the results of 20, it is understood that the water absorbing resin containing the deodorant a and the deodorant b is excellent in deodorizing property against the basic gas and the sulfur-containing gas.

In each of the above Examples, the deodorant water-absorbent resin was preliminarily absorbed in the same manner except that 80 parts of water was added to 100 parts of the water-absorbent resin after the deodorant was added to the water-absorbent resin powder. When prepared and subjected to the above deodorant test, the test results were almost the same as those shown in Tables 7 and 8 above.

The sample obtained in Example 1 was left in a container filled with a large amount of ammonia gas to once eliminate the deodorizing property, and then the sample was irradiated with ultraviolet rays for 8 days with a germicidal lamp, and the above test was conducted. When a deodorizing test against ammonia gas was conducted in the same manner as in the method, the same excellent deodorizing property as in Example 1 in Table 6 was exhibited.

[0034]

The deodorant water-absorbent resin of the present invention contains an deodorant that is insoluble or sparingly soluble in water and is excellent in safety for the human body. The resin has excellent deodorant properties. That is, the water absorbing resin containing the deodorant a is excellent in deodorizing property against basic gas, and the water absorbing resin containing the deodorant b is excellent in deodorizing property against sulfur-containing gas and lower fatty acid gas. .. Further, the deodorant a and the deodorant b can regenerate the deodorizing property with respect to the basic gas by irradiation with ultraviolet rays. The deodorant water-absorbent resin of the present invention is
Used for sanitary materials such as paper diapers and sanitary napkins used to treat urination of infants, bedridden elderly people, sick people, etc.
It has an excellent effect of suppressing a bad odor when it is in contact with a human body for a long time or after use.

Claims (2)

[Claims] 1. A deodorant water-absorbing resin containing a tetravalent metal phosphate represented by the following general formula [1] that is insoluble or sparingly soluble in water. H _a M _b O _c (PO ₄ ) _d ·nH ₂ O [1] [M is a tetravalent metal, and a, b, c and d are represented by the formula (a+4
It is a positive number that satisfies b=2c+3d (however, c may be 0), and n is 0 or a positive number. ] 2. A deodorant water-absorbing resin containing a tetravalent metal phosphate represented by the following general formula [2] which is insoluble or sparingly soluble in water. _{H a A b B c M d} O e (PO 4) f · nH 2 O [2] [A is a monovalent metal, B is a divalent metal, M is a tetravalent metal, a, b , C, e and n are 0 or a positive number, b and c are not both 0, d and f are positive numbers, and a, b, c, d, e and f are expressed by the formula ( a+b+2c
+4d=2e+3f) is satisfied. ]