JPH08100102A - Polyacetal resin composition - Google Patents

Abstract

PURPOSE: To obtain an antifungal and antibacterial polyacetal resin composition having excellent chlorine water resistance and capable of being used even in highly humid environments such as the surroundings of city water cocks, bath rooms and kitchens. CONSTITUTION: This polyacetal resin composition comprises (A) 100 pts.wt. of a polyacetal resin, (B) 0.05-5 pts.wt. of an antioxidizing agent, (C) 0.01-5 pts.wt. of a specific zinc compound, and (D) 0.001-2 pts.wt. of an organic compound selected from tetrachloroisophthalonitrile, 2-pyridinethiol-1-oxide or its metal salt, 2,3,5,6-tetrachloro-4-(methylsulfonyl)pyridine and p-aminoacetoanilide.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyacetal resin composition which is suitable for use under high temperature and high humidity conditions where molds and bacteria easily grow, and which is excellent in mold prevention and antibacterial properties.

[0002]

2. Description of the Related Art In recent years,
Awareness of cleanliness has been improved along with improvement of living standard, and resistance to mold and bacteria has been required for products used in the field of general industry. Generally, a plastic material is a material on which molds and bacteria are relatively difficult to propagate, but since dirt and dust attached to the surface of a molded product serve as a nutrient source for molds, they always have the problem of the generation of these microorganisms. These propagated fungi not only impair the surface appearance of the molded product, but also cause various problems such as generating a bad odor, damaging the environment, contaminating contacted substances, and deteriorating the properties of materials. Become. In addition, direct adverse effects on the human body such as pediatric bronchial asthma due to mold spores and bacterial infection in hospitals, which have become a problem in recent years, have been reported. Polyacetal resin is widely used in the fields of electric machinery, automobiles, various machines, building materials, functional miscellaneous goods, etc. due to its excellent mechanical properties, heat resistance, chemical resistance, and electrical resistance, and its easy molding process. It is a material. It is rarely used for external parts that come into direct contact with the human body, but it is often used for parts of equipment very closely related to clothing, food and living, such as air conditioners, food processing equipment, waste treatment machines, humidifiers, etc. There is also a great demand for imparting sex. In order to impart antifungal and antibacterial properties to the polyacetal resin, there is known a method of adding a specific metal compound as shown in JP-A-5-230325 previously filed by the applicant of the present application. As a result, a polyacetal resin composition having sufficient antifungal and antibacterial properties was obtained in the initial stage, but as a result of further study after that, when such a material was used around water, depending on the environmental conditions, the polyacetal resin composition was obtained. The surface appearance of the molded product is cloudy,
It was found to be aggravating and not yet sufficient for long-term use. As an environment in which molds and bacteria can actually easily propagate, there is a humid environment such as around a tap water, but tap water is generally subjected to hydrogen sterilization treatment, and the molded products used here have a high concentration against chlorine water over a wide concentration range. Durability (chlorine water resistance) is required. That is, as a polyacetal resin material having antifungal and antibacterial properties, it is desired to develop a material having excellent chlorine resistance, which can be used even in a humid environment such as around a water supply, a bathroom or a kitchen. No material has yet been provided that satisfies such required performance.

[0003]

As a result of intensive studies to solve the above problems, the present inventors have combined a polyacetal resin with a hindered phenolic antioxidant, a zinc compound and a specific organic compound. It has been found that a polyacetal resin composition having antifungal / antibacterial properties and an excellent chlorine water resistance, which meet the original purpose, can be obtained by blending the above components, and arrived at the present invention. That is, the present invention is (A)
(B) Antioxidant 0.05 to 5 parts by weight per 100 parts by weight of polyacetal resin (C) 1% by weight zinc compound with a pH of 7 or more measured in a solution suspended or purified in pure water at a concentration of 0.01% 0.01 To 5 parts by weight (D) tetrachloroisophthalonitrile, 2-pyridinethiol-1-oxide or a metal salt thereof, 2,3,5,6-tetrachloro-4- (methylsulfonyl) pyridine and p
The present invention relates to a polyacetal resin composition containing 0.001 to 2 parts by weight of one or more organic compounds selected from aminoacetanilide.

Hereinafter, the present invention will be described in detail. (B) Antioxidants used in the present invention include hindered phenols such as 2,2′-methylenebis (4-methyl-6-t).
-Butylphenol), hexamethyleneglycol-bis (3,5-di-t-butyl-4-hydroxyhydrocinnamate), tetrakis [methylene (3,5-di-t-butyl-4-hydroxyhydrocinnamate)] methane,
Triethylene glycol-bis-3- (3-t-butyl-4-hydroxy-5-methylphenyl) propionate, 1,3,5-trimethyl-2,4,6-tris (3,5-di-
t-butyl-4-hydroxy-benzyl) benzene, n
-Octadecyl-3- (4'-hydroxy-3 ', 5'-di-
t-butylphenol) propionate, 4,4'-methylenebis (2,6-di-t-butylphenol), 4,4'-butylidene-bis- (6-t-butyl-3-methyl-phenol), di-stearyl -3,5-di-t-butyl-4
-Hydroxybenzylphosphonate, 2-t-butyl-
6- (3-t-butyl-5-methyl-2-hydroxybenzyl) -4-methylphenyl acrylate, 3,9-bis {2- [3- (3-t-butyl-4-hydroxy-5)
-Methylphenyl) propionyloxy] -1,1-dimethylethyl} -2,4,8,10-tetraoxaspiro [5,5]
Undecane and other hindered amines such as 4-acetoxy-2,2,6,6-tetramethylpiperidine, 4-stearoyloxy-2,2,6,6-tetramethylpiperidine, 4
-Acryloyloxy-2,2,6,6-tetramethylpiperidine, 4-methoxy-2,2,6,6-tetramethylpiperidine, 4-benzoyloxy-2,2,6,6-tetramethylpiperidine, 4 -Cyclohexyloxy-2,2,6,6-tetramethylpiperidine, 4-phenoxy-2,2,6,6-tetramethylpiperidine, 4-benzyloxy-2,2,6,6-
Tetramethylpiperidine, 4- (phenylcarbamoyoxy) -2,2,6,6-tetramethylpiperidine, bis (2,
2,6,6-Tetramethyl-4-piperidyl) oxalate, bis (2,2,6,6-tetramethyl-4-piperidyl)
Malonate, bis (2,2,6,6-tetramethyl-4-piperidyl) adipate, bis (2,2,6,6-tetramethyl-
4-piperidyl) sebacate, bis (1,2,2,6,6-pentamethyl-piperidyl) sebacate, bis (2,2,6,6-
Tetramethyl-4-piperidyl) terephthalate, 1,2
-Bis (2,2,6,6-tetramethyl-4-piperidyloxy) ethane, bis (2,2,6,6-tetramethyl-4-piperidyl) hexamethylene-1,6-dicarbamate, bis ( 1-methyl-2,2,6,6-tetramethyl-4-piperidyl) adipate, tris (2,2,6,6-tetramethyl-4)
-Piperidyl) benzene-1,3,5-tricarboxylate and the like. In addition, high molecular weight piperidine derivative polycondensates such as dimethyl succinate 1- (2-hydroxyethyl) -4-hydroxy-2,2,6,6-tetramethylpiperidine polycondensate, poly [(6- Morpholino-S-triazine-2,4-diyl) [2,2,6,6-tetramethyl-
4-piperidyl] imino] -hexamethylene [(2,2,6,
6-Tetramethyl-4-piperidyl) imino]] and the like are also effective, and at least one kind or two or more kinds thereof can be used. Among these, tetrakis [methylene (3,5-di-t-butyl-4-hydroxyhydrocinnamate)] methane, triethylene glycol-bis-3- (3-t-butyl-4-hydroxy-5-methyl) Phenyl) propionate, 3,9-bis {2- [3-
(3-t-Butyl-4-hydroxy-5-methylphenyl) propionyloxy] -1,1-dimethylethyl}-
2,4,8,10-Tetraoxaspiro [5,5] undecane, poly [(6-morpholino-S-triazine-2,4-diyl) [2,2,6,6-tetramethyl-4-piperidyl ] Imino] -hexamethylene [(2,2,6,6-tetramethyl-4
-Piperidyl) imino]] is a particularly preferred substance.
The addition amount of the component (B) in the present invention is 0.01 to 5.0 parts by weight based on 100 parts by weight of the (A) polyacetal resin.

Next, the zinc compound (C) used in the present invention has a pH of 7 or more as measured in a liquid prepared by suspending or dissolving water in pure water at a concentration of 1% by weight. Specific examples thereof include zinc metal, zinc oxide, zinc borate, zinc carbonate, zinc phosphate, zinc hydroxide, and hydrotalcite containing zinc metal. Further, two or more selected from these may be combined and blended. As the above-mentioned hydrotalcite, any one can be used as long as it has zinc as a metal component, but a hydrotalcite having aluminum, magnesium and zinc represented by the following general formula (1) as metal components is particularly preferable. . General formula (1) Al _x Mg _(zk) Zn _k (OH) ₆ · (a / 2) (CO ₃ ) · mH ₂ O (where x and z are 0.6 ≦ x ≦ 3 and 0 <z ≦, respectively) 2.
Is a number of 4, and m and a are 0 ≦ m ≦ 3 and 0 ≦ a ≦
Is a number of 6 and k is a number of 0 ≦ k ≦ 1.2.
Further, in order to improve the handling property of these hydrotalcites, it is desirable that the surface thereof is treated with a fatty acid. As such a fatty acid, lauric acid,
Examples are myristic acid, palmitic acid, stearic acid and behenic acid. In addition to these, examples of zinc compounds include salts of strong acids such as zinc sulfate and zinc nitrate, fatty acid salts such as zinc benzoate, and aromatic carboxylates such as zinc salicylate. The suspensions or aqueous solutions all have a pH of less than 7, and the polyacetal resin in which these compounds have been kneaded has greatly reduced thermal stability and water resistance. Water resistance is indispensable as a material used in an environment where molds easily propagate, and from this point, it is necessary to select a zinc compound having a pH of 7 or more in an aqueous suspension or aqueous solution. Among the above examples, zinc oxide, zinc borate, zinc carbonate, zinc hydroxide, hydrotalcite containing a zinc metal is preferable in that the thermal stability of the polyacetal resin does not decrease the water resistance, and zinc oxide is particularly preferable. It is preferably used from the viewpoints of safety, cost, and not changing the physical properties of the polyacetal resin. (C) The zinc compound is added in an amount of 0.1 parts by weight per 100 parts by weight of the (A) polyacetal resin.
The amount is 01 to 5 parts by weight, preferably 0.1 to 2 parts by weight. If the added amount is larger than this, the effect is saturated, which causes discoloration and adversely affects the physical properties of the polyacetal resin. On the other hand, if the amount added is less than this, the desired effect will not be exhibited.

Next, as the organic compound of the component (D) added and blended in the present invention, tetrachloroisophthalonitrile, 2-pyridinethiol-1-oxide or a metal salt thereof, 2,3,5,6- Tetrachloro-4- (methylsulfonyl) pyridine, p-aminoacetanilide, and
One or more selected from these are used. By using two or more types of mixture, not only the fungicidal and antibacterial effects against a wider range of molds and bacteria but also
An effect that synergistically enhances each performance is also obtained. 2-
The metal salt of pyridinethiol-1-oxide includes sodium salt, zinc salt and the like, but the zinc salt is preferable from the viewpoint of antifungal effect and safety. There are many other fungicides among these organic compounds, but they have heat resistance at the melt-kneading temperature of polyacetal resin (180-230 ° C) and are safe for humans. The above compounds were selected from the viewpoints of not changing the physical properties of the polyacetal resin. Compounded in polyacetal resin composition (D)
The amount of the organic compound added is 0.001 to 2 parts by weight, preferably 0.005 to 1 part by weight, based on 100 parts by weight of the polyacetal resin. If the amount added exceeds this range, bleeding may occur, which may cause mold contamination during molding, or cause discoloration of the resin composition, which is not preferable. On the other hand, if it is less than this, the desired effect cannot be obtained. In the present invention, such (B) antioxidant, (C) zinc compound, (D) organic compound is directly added to the polyacetal resin and blended, and melt-kneaded to uniformly disperse in the resin. The effect can be exhibited. In order to disperse them uniformly, a method of crushing them in advance and adding them as fine particles, a method of adsorbing / supporting these on a fine inorganic fine particle carrier and adding and blending them are used. As the inorganic fine particle carrier used for such a purpose, those which do not impair the performance of the present invention are used, and specific examples thereof include alumina, magnesia, zirconia, zeolite, mica, talc, calcium carbonate,
Inorganic powders such as calcium silicate, diatomaceous earth, perlite, bentonite, montmorillonite, and hydrotalcite.

The polyacetal resin (A) to which such an additive is added is a polymer compound having an oxymethylene group (-CH ₂ O-) as a main constituent unit, and other than the polyacetal homopolymer and the oxymethylene group. It may be any of a polyacetal copolymer, a terpolymer and a block copolymer containing a small amount of structural units, and the molecule may have not only a linear structure but also a branched or crosslinked structure. or,
There is no particular limitation on the degree of polymerization or the like.

Further, in the present invention, a substance having at least one of formaldehyde-reactive amino group and hydroxyl group as the component (E) is preferably used as an auxiliary agent for sufficiently exhibiting the effect of the component (C). . This is because the polyacetal molded product partially contains formic acid in which formaldehyde is oxidized during resin molding and reacts with the component (C) of the present application, and thus suppresses the action of weakening the inherent effect of them. . Such a substance having one or more formaldehyde-reactive amino groups and hydroxyl groups means melamine, benzoguanamine and polycondensates thereof with formaldehyde, polyethylene glycol, polyglycerin, fatty acid monoesters of glycerin and diglycerin, for example, glycerin mono. Stearate, diglycerin monostearate,
Glycerin monoisostearate, diglycerin monoisostearate, glycerin monopalmitate, diglycerin monopalmitate, ethylene-bis (stearylamide), hexamethylene-bis (stearylamide), bis (stearoylaminoethyl) sebacyldiamide, fatty acid Metal salts such as lauric acid, myristic acid, palmitic acid, stearic acid, behenic acid Ca salt, Zn
Examples thereof include salts, Na salts, K salts, and salts of derivatives of these fatty acids, such as calcium hydroxystearate, and at least one kind or two or more kinds thereof can be used.
Among these, melamine, a polycondensate of melamine and formaldehyde glycerin and a fatty acid monoester of glycerin are particularly preferable substances. The component (E) is
(A) 0.01 to 3.0 parts by weight, preferably 0.05 to 1.0 parts by weight, is added to 100 parts by weight of the polyacetal resin. If the amount added is larger than this, the mechanical properties of the resin composition may be impaired, and if the amount added is smaller than this, the intended effect cannot be obtained. Further, the resin composition of the present invention may further contain various known additives depending on the purpose. Examples of additives include various stabilizers, colorants, lubricants, release agents, nucleating agents,
Antistatic agents, different polymers, organic modifiers, etc. Further, as long as the performance of the resin material intended by the present invention is not significantly reduced, one or more kinds of fibrous or plate-like fillers or powder fillers such as inorganic, organic, and metallic materials are used. You can also The method for preparing the composition of the present invention is not particularly limited, and can be easily prepared by known equipment and methods generally used as conventional resin composition preparation methods.
For example, i) after mixing each component, kneading and extruding with an extruder to prepare pellets, and then molding, ii) once preparing pellets having different compositions, and mixing the pellets in a predetermined amount to mold. Any method such as a method of obtaining a molded article having a desired composition after molding and iii) a method of directly charging one or more of each component into a molding machine can be used. In addition, mixing a part of the resin component in the form of fine powder with the other components and adding it is a preferable method for uniformly blending these components. Further, a method of preparing a masterbatch having a high concentration of the compound of the present invention and adding this to other pellets at the time of molding can also be used. The resin composition of the present invention can be molded by any of extrusion molding, injection molding, compression molding, vacuum molding, blow molding, and foam molding.

A molded article obtained by molding the composition of the present invention is
Shows 95% or more weight retention when immersed in chlorine water with a concentration of 10ppm at 60 ℃ for 40 days. Therefore, the use of the polyacetal resin composition of the present invention can be applied to all of the applications in which the polyacetal resin is usually used, but it is particularly suitable for applications that require antifungal properties and are considered to cause harmful effects by chlorine water. Can be used for If a specific molded article is illustrated, at least a part of water-related equipment composed of a polyacetal resin molded article, for example, a water meter,
Pump, water tank, septic tank, water heater, water purifier, water conditioner, water sprinkler, toilet accessory, kitchen accessory, bathroom accessory,
Toilet accessory equipment, piping, etc., and specific parts include gears, cams, levers, pulleys, bearings, chassis, packing, gaskets, water supply pipes, joints, nozzles, shower heads, floats, spindles, guides, spinning tops. , A ball tap, a screen mesh, a spout, a faucet, a tank, a water receiving container and the like.

[0010]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited thereto. First, the pH of the zinc compounds used in Examples and Comparative Examples was measured by the following method. A. pH measurement Prepare a sample solution by suspending or water-solubilizing each zinc compound at a concentration of 1.0% by weight in 100 ml of water, and stir the sample solution with a stirrer, while using the HORIBA Industrial Castany LAB pH Meter F-12. Measured using (Temperature: 23
° C). The results are shown in Table 1.

Examples 1 to 15 Polyacetal copolymers in various proportions shown in Table 2 were used.
(B) Antioxidant, (C) Zinc compound, (D) Organic compound, and (E) Formaldehyde-reactive amino group, a substance having a hydroxyl group are added and mixed, melt-kneaded with a twin-screw extruder, and pelletized. Was prepared. Then, a test piece (50 mm x 70 mm x 3 mm thick) was produced by injection molding using this pellet, and the following evaluation was performed. Table 2 shows the results. The method of the mold resistance test is as follows. B. Antifungal effect 1) Standard fungi and fungi a: Aspergillus niger b: Black mold (Cladosporium cladosporioides) c: Red mold (Trichoderma sp.) 2) Test method Mold resistance test Performed in accordance with JIS Z 2911 . That is, after sterilizing potato / glucose agar medium (pH 6.0) with high pressure steam,
25 ml each was dispensed into a Petri dish of cm and coagulated to prepare an agar plate. After placing the test piece on this agar plate and spraying 1 ml of the spore suspension in which the test fungal spores were suspended,
After culturing at 14 ° C. for 14 days, the growth state of mycelia formed on the surface of the test piece was examined, and the effect of mold resistance was judged according to the following 5 grades. Growth status display of the sample surface of the test bacterium No growth of the bacterium; 0 Slight growth (less than 10% of the sample area); 1 Little growth (10% or more and less than 30% of the sample area); 2 Intermediate growth (of the sample area) 30% or more and less than 60%); 3 vigorous growth (over 60% of the sample area); 4 The results are shown in Table 2. Further, when these fungicidal materials are practically used, it is considered that they are often used around water, so the chlorine water resistance was evaluated as follows in a accelerated manner. C. Chlorine resistant water injection Molded ASTM No. 1 dumbbell by injection molding, temperature 60 ℃
And, dip it in a chlorine solution adjusted to a concentration of 10 ppm and take it out at specified time intervals. After the treated molded article was dried at 105 ° C. for 3 hours, the weight of the molded article was measured. The weights of all the molded articles were measured before this treatment, and the weight retention rate after the treatment with the chlorine aqueous solution was calculated from the weight difference before and after the treatment using the following formula.

[0012]

[Equation 1]

D. Water resistance C Using the same molded piece as used for the chlorine resistance evaluation, it is immersed in pure water at a temperature of 120 ° C. and taken out after a predetermined time. After drying the molded product at 105 ℃ for 3 hours,
The whitening phenomenon on the surface of the molded product was evaluated according to the following 5 grades. 1 2 3 4 5 Good ← No change ──Slightly ──Slightly ──Whitening ──Whitening terrible → Bad Comparative Examples 1 to 7 For comparison, as shown in Table 3, (B) antioxidant,
The same evaluation was performed in the case where the (C) zinc compound and the (D) organic compound were not added and the case where a compound outside the stipulations of the present invention was added. The results are shown in Table 3. The various substances used are as follows. Note-1. Antioxidant B-1: Triethylene glycol-bis- [3- (3-
t-butyl-4-hydroxy-5-methylphenyl) propionate] B-2: poly [(6-morpholino-S-triazine-
2,4-diyl) [2,2,6,6-tetramethyl-4-piperidyl] imino] -hexamethylene [(2,2,6,6-tetramethyl-4-piperidyl] imino]) Note-2 ． Zinc-containing compound C-1: Zinc oxide C-2: Zinc carbonate C-3: Hydrotalcite C-4: Zinc borate C'-1: Zinc sulfate Note-3. Organic compound D-1: Pyridinethiol-1-oxide zinc salt D-2: Tetrachloroisophthalonitrile D-3: 2,3,5,6-Tetrachloro-4- (methylsulfonyl) pyridine Note-4. Substances having formaldehyde-reactive groups E-1: Melamine-formaldehyde polycondensate E-2: Glycerin monostearate E-3: Calcium 12-hydroxystearate

[0014]

[Table 1]

[0015]

[Table 2]

[0016]

[Table 3]

[0017]

As is clear from the above results, it was confirmed that the composition of the present invention has sufficient antifungal properties without causing deterioration of water resistance which is a problem in practical use. . It has also been confirmed that there is no problem with mechanical strength and heat resistance, and because it is a color that can be colored, it can be used not only for applications where polyacetal resin has been used, but also for water supply, air conditioning / heating / cooling equipment, sanitary equipment, etc. Widely available.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location C08K 5/37 5/41

Claims (6)

[Claims] 1. Measured with a liquid prepared by suspending or dissolving in (A) 100 parts by weight of polyacetal resin, (B) 0.05 to 5 parts by weight of antioxidant (C) 1% by weight in pure water. Zinc compound having a pH of 7 or more 0.01 to 5 parts by weight (D) Tetrachloroisophthalonitrile, 2-pyridinethiol-1-oxide or a metal salt thereof, 2,3,5,6-tetrachloro-4- (methylsulfonyl) ) Pyridine and p
A polyacetal resin composition containing 0.001 to 2 parts by weight of one or more organic compounds selected from aminoacetanilide. 2. The (C) zinc compound is zinc metal, zinc oxide,
The polyacetal resin composition according to claim 1, which is one or more selected from hydrotalcites containing zinc borate, zinc carbonate, zinc phosphate, zinc hydroxide, and zinc metal. 3. The polyacetal resin according to claim 1, further comprising 0.01 to 3 parts by weight of (E) one or more substances having one or more formaldehyde-reactive amino groups and hydroxyl groups. Composition. 4. A polyacetal resin molding excellent in chlorine water resistance, which is obtained by molding the polyacetal resin composition according to claim 1. 5. The polyacetal resin molding according to claim 4, wherein the molding is a water supply member. 6. A molded article is 40 ° C. at 60 ° C. in chlorine water having a concentration of 10 ppm.
The polyacetal resin molded product according to claim 4 or 5, which has a weight retention of 95% or more when immersed for a day.