JPH0657032A - Antimicrobial nylon resin composition - Google Patents

Abstract

PURPOSE:To provide a resin composition, comprising a specific inorganic antimicrobial agent, nylon resin and a hindered amine-based polymer additive, capable of manifesting excellent antimicrobial properties and useful as moldings, etc., with hardly any discoloration peculiar to nylon resin. CONSTITUTION:The antimicrobial nylon resin composition is obtained by blending (A) an antimicrobial agent expressed by the formula {M<1> is a metal ion such as silver, copper, zinc, tin, mercury, lead, iron, cobalt, nickel, manganese, arsenic, antimony, bismuth, barium, cadmium or chromium; M<2> is a tetravalent metal' A is an alkali metal ion alkaline earth metal ion, ammonium ion or H ion; 0<=(n)<=6; (a) and (b) are positive numbers satisfying (la+mb)=1 or 2; [(l) is the valence of M<1>; (m) is the valence of A]; (c) is 1 or 2; (d) is 2 or 3}, (B) a nylon resin (e.g. nylon 6) and (C) a hindered amine-based polymer additive. This resin composition is capable of manifesting excellent antimicrobial properties with hardly any discoloration peculiar to the nylon resin.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a nylon resin composition comprising a specific phosphate compound having antibacterial properties, a nylon resin and a hindered amine polymer additive. More specifically, the present invention relates to an antibacterial nylon resin composition exhibiting a stable antibacterial effect with little deterioration over time during processing, storage and use, and is required to have antibacterial, antifungal and antialgal properties. It can be used as various plastic molded products such as fibers, films, sheets and pellets.

[0002]

2. Description of the Related Art A number of antibacterial agents have already been proposed which can be incorporated into fibers, paints, resin moldings, papers, binders and the like to exert antibacterial properties. Among them, inorganic antibacterial agents have excellent durability. Recently, it has been attracting attention.

As an inorganic antibacterial agent, there is known one in which a metal exhibiting antibacterial properties such as silver or copper (hereinafter sometimes referred to as antibacterial metal) is supported on activated carbon, apatite, zeolite or the like. These are more safe than organic antibacterial agents, have a long lasting antibacterial effect because they do not volatilize or decompose, and have excellent heat resistance. Therefore, an antibacterial resin composition is obtained by mixing these antibacterial agents and various polymer compounds, and is processed into a fibrous shape, a film shape, a pellet shape, a plate shape, etc.,
It is used for various purposes.

However, since the antibacterial agent itself using activated carbon as a carrier is black, the antibacterial resin composition obtained by mixing with various polymers has a problem in appearance, that is, it is colored. Further, when brought into contact with a liquid, there is a problem that the antibacterial metal is easily eluted and the antibacterial effect cannot be maintained for a long time.

Further, the antibacterial agent using apatite and zeolite as the carrier has a relatively small amount of elution of the antibacterial metal when brought into contact with a neutral liquid and has a long antibacterial effect as compared with the antibacterial agent using the activated carbon as a carrier. Although excellent in terms of sustainability, all of these antibacterial agents have low acid resistance, and the skeleton structure is easily destroyed in a dilute acidic aqueous solution having a pH of about 4 to elute the antibacterial metal. In addition, it is difficult to maintain the antibacterial effect for a long time, and there are also safety problems due to the eluted antibacterial metal, and when the composition is prepared by mixing it with various polymers, the composition after the preparation However, there is a problem that the resin discolors during storage or use and causes deterioration of the resin.

In order to solve these problems, an antibacterial resin composition comprising a specific phosphate compound and various resins has been proposed (JP-A-3-83905, JP-A-3-8).
3906). However, in the case of a nylon resin, when the antibacterial agent composed of the specific phosphate compound described in the above-mentioned patent publication is contained, there is a problem that discoloration occurs, although there is a slight difference in degree, and its improvement Is desired. When an inorganic antibacterial agent is contained, the reason why the discoloration of the nylon resin is more remarkable than that of other resins is that the nylon resin has an NH group and has water absorbability. Are believed to be unique to the structure and properties of the resin.

On the other hand, for general molding resins, it has been proposed to add various stabilizers to the resin for the purpose of preventing such discoloration caused by silver ions. As a compound to be added to the antibacterial resin composition comprising the antibacterial zeolite and the resin, benzotriazole compounds, oxalic acid anilide compounds, salicylic acid compounds, hindered amine compounds and hindered phenol compounds are known. (Japanese Patent Laid-Open No. 63-265958).

As described above, various stabilizers for preventing discoloration of various resins containing antibacterial zeolite have been proposed, but the discoloration of nylon resin can be sufficiently suppressed only by using these stabilizers. However, improvement is desired.

[0009]

Nylon resin containing an inorganic antibacterial agent is more likely to cause discoloration due to heat during processing and is less prone to deterioration over time than other resins such as polyolefin, ABS resin and silicone resin. The degree of gradual color change is high, and the product value is often significantly reduced. An object of the present invention is to provide a nylon resin composition containing an inorganic antibacterial agent, capable of exhibiting excellent antibacterial properties and having almost no discoloration peculiar to nylon resins.

[0010]

DISCLOSURE OF THE INVENTION The inventors of the present invention have made extensive studies to solve the above problems, and as a result, disclosed in Japanese Patent Laid-Open No. 3-83
It is extremely effective to blend an antibacterial agent composed of a specific phosphate compound described in JP-A No. 905 or JP-A-3-83906 and a polymer additive composed of a specific compound into a nylon resin. Therefore, the present invention has been completed. That is, the present invention provides the following general formula [1]
An antibacterial nylon resin composition characterized by containing an antibacterial agent, a nylon resin, and a hindered amine-based polymer additive. M ¹ _{a Ab} M ² _c (PO ₄ ) _d · nH ₂ O [1] (M ¹ is silver, copper, zinc, tin, mercury, lead, iron, cobalt,
At least one metal ion selected from nickel, manganese, arsenic, antimony, bismuth, barium, cadmium or chromium, A is an alkali metal ion,
At least one ion selected from alkaline earth metal ions, ammonium ions or hydrogen ions,
M ² is a tetravalent metal, n is a number satisfying 0 ≦ n ≦ 6, a and b are positive numbers satisfying la + mb = 1 or la + mb = 2, and c and d are la + mb = 1, c =
2, d = 3, and la + mb = 2, c = 1, d =
It is 2. However, 1 is the valence of M ¹ and m is the valence of A. )

The present invention will be described in detail below. Nylon Resin Nylon resin in the present invention is a synthetic resin obtained by polycondensation of diamine and dicarboxylic acid, and is a crystalline or non-crystalline linear polymer having an acid amide bond (CONH) in the polymer main chain. is there. Preferred specific examples of nylon resin include nylon 6, nylon 10, nylon 11,
Examples include nylon 12, nylon 66, nylon 69, nylon 610 and nylon 612. As the nylon resin in the present invention, a dry type used for so-called molding is suitable, but other types may be used. If the nylon resin contains a liquid substance such as water or an organic solvent, or is a paint, paste or the like dispersed in these liquid substances, the effect of the specific polymer additive in the present invention is exerted. Can be difficult. The form of the nylon resin is arbitrary, and specifically, there are various forms such as lumps, powders, grains or flakes.

Further, in order to improve the physical properties of the nylon resin composition, various other additives known as additives to the nylon resin may be mixed if necessary. Specific examples include pigments, dyes, antioxidants, light stabilizers, moistureproofing agents, and extenders. The combined use of a benzotriazole-based compound, a benzophenone-based compound, etc. often improves the discoloration preventing effect.

Antibacterial Agent The antibacterial agent in the present invention is a compound represented by the following general formula [1]. M ¹ _{a Ab} M ² ₂ (PO ₄ ) ^d · nH ₂ O [1] (M ¹ is silver, copper, zinc, tin, mercury, lead, iron, cobalt,
At least one metal ion selected from nickel, manganese, arsenic, antimony, bismuth, barium, cadmium or chromium, A is an alkali metal ion,
At least one ion selected from alkaline earth metal ions, ammonium ions or hydrogen ions,
M ² is a tetravalent metal, n is a number satisfying 0 ≦ n ≦ 6, a and b are positive numbers satisfying la + mb = 1 or la + mb = 2, and c and d are la + mb = 1, c =
2, d = 3, and la + mb = 2, c = 1, d =
It is 2. However, 1 is the valence of M ¹ and m is the valence of A. ) The compound represented by the above general formula [1] is la +
When mb = 1, the compound is an amorphous compound or a crystalline compound belonging to the space group R ³ c having coefficients c = 2 and d = 3, and each constituent ion represents a compound forming a three-dimensional network structure, and la + mb = When 2, it represents a compound in which amorphous or each constituent ion having each coefficient of c = 1 and d = 2 forms a layered structure.

As the phosphate compound used in the present invention, since there is little discoloration when exposed to sunlight, la +
A crystalline compound having an amorphous or three-dimensional network structure having respective coefficients of mb = 1 and c = 2, d = 3 is preferable, and a crystalline compound is more preferable. M ¹ in the above general formula [1] is all known as a metal exhibiting antifungal and antibacterial properties. Among these, silver is not only safe but also antifungal, antibacterial and antialgal. It is effective as a metal that can be increased. A in the above general formula [1]
Is at least one ion selected from an alkali metal ion, an alkaline earth metal ion, an ammonium ion or a hydrogen ion, and preferred specific examples include a metal ion such as lithium, sodium and potassium, an alkali such as magnesium or calcium, and the like. There are earth metal ions or hydrogen ions, and among these, lithium, sodium, due to the stability of the compound and availability in knitting,
Ammonium ions and hydrogen ions are the preferred ions. M ² in the above general formula [1] is a tetravalent metal, and preferred specific examples include metals such as zirconium, titanium and tin, and zirconium is a particularly preferred tetravalent metal. Specific preferred examples of the phosphate compound of the general formula [1] include the following: Ag _0.005 Li _0.995 Zr ₂ (PO ₄ ) ₃ Ag _0.01 (NH ₄ ) _0.99 Zr ₂ (PO ₄ ) ₃ Ag _0.05 Na _0.95 Zr ₂ (PO ₄ ) ₃ Ag _0.2 K _0.8 Ti ₂ (PO ₄ ) ₃ Ag _0.1 H _0.9 Zr ₂ (PO ₄ ) ₃ Ag _0.05 H _0.05 Na _0.90 Zr ₂ (PO ₄ ) ₃ Ag _0.05 H _0.55 Na _0.40 Zr ₂ (PO ₄ ) ₃

The method for synthesizing the phosphate compound used in the present invention includes a calcination method, a wet method, a hydrothermal method and the like. For example, in the case of synthesizing by the wet method, it can be easily obtained as follows. it can. ○ Synthesis of network structure phosphate While adding an aqueous solution of zirconium oxynitrate and sodium nitrate, add oxalic acid and phosphoric acid into the solution. Adjust the pH of the reaction solution to 3.5 with a caustic soda solution.
After heating to reflux for 78 hours, the precipitate is filtered, washed with water,
Dried and crushed, reticulated zirconium phosphate [NaZr ₂
(PO ₄ ) ₃ ] is obtained. The compound represented by the general formula [1] is obtained by immersing this in an aqueous solution containing silver ions at an appropriate concentration.

In order to exhibit antifungal, antibacterial and antialgal properties, the larger the value of a in the general formula [1] is, the better.
When the value of a is 0.001 or more, antifungal, antibacterial and antialgal properties can be sufficiently exhibited. The value of a is 0.
If it is less than 001, it may be difficult to exert antifungal, antibacterial and antialgal properties for a long time, and in consideration of economical efficiency, the value of a is 0.01 or more and 0.5 or less. It is preferable that

The preferable mixing ratio of the antibacterial agent is 0.05 to 50 parts per 100 parts by weight of the antibacterial nylon resin composition (hereinafter, simply referred to as "part"), and more preferably 0 considering the antibacterial effect and economy. 0.5 to 10 parts.

Hindered Amine Polymer Additive The hindered amine polymer additive in the present invention is roughly classified into three types, a low molecular weight type, an oligomer type and a low base type. All of these hindered amine-based polymer additives have a structure represented by the following general formula [2].

[0019]

[Chemical 1] R ¹ and R ² in the above general formula [2] are organic groups.

The low molecular weight type compound is a compound in which R ¹ or R ² in the above general formula [2] is a low molecular weight organic group, and preferable specific compounds include the following compounds.

[0021]

[Chemical 2]

[0022]

[Chemical 3]

[0023]

[Chemical 4]

The oligomer type compound is a compound in which R ¹ or R ² in the above general formula [2] is an organic group of the oligomer, and preferable specific compounds include the following compounds.

[0025]

[Chemical 5]

[0026]

[Chemical 6]

[0027]

[Chemical 7]

The low basic type compound is a compound in which R ¹ or R ² in the above formula [2] is a low basic type organic group, and preferable specific compounds include the following compounds. To be

[0029]

[Chemical 8]

These hindered amine-based polymer additives are conventionally known as polymer light stabilizers. In the present invention, however, the hindered amine-based polymer additive is a specific phosphoric acid. When blended in a nylon resin composition with a salt-based antibacterial agent, the discoloration peculiar to a nylon resin is significantly suppressed when molding and spinning are added to this, and the antibacterial and antifungal properties last for a long time. This fact is extremely surprising.

The preferred blending ratio of the hindered amine polymer additive is 0.01 to 100 parts by weight of the nylon resin.
10 parts, more preferably 0.1 _to 5 parts. If the amount is less than 0.01 part, the discoloration of the nylon resin composition may not be sufficiently suppressed, while if the amount is more than 10 parts, the discoloration preventing effect is hardly improved, and the physical properties of the nylon resin are rather increased. Of the hindered amine-based polymer additive may cause yellowing.

The antibacterial nylon resin composition of the present invention comprises a phosphate represented by the above general formula [1] while heating and pressurizing or depressurizing at an appropriate temperature and pressure according to the characteristics of the nylon resin used. The compound and the hindered amine polymer additive can be easily prepared by mixing, mixing or kneading with a nylon resin, and specific operations thereof may be carried out by a conventional method. The resin composition can be molded into various forms.

In the antibacterial nylon resin composition according to the present invention and the molded article obtained therefrom, silver ions are supported on the antibacterial agent very chemically and physically, and the hindered amine polymer additive is used. As a result, the discoloration-preventing effect is exerted, so that discoloration hardly occurs, and in addition, it has antibacterial, antibacterial and algae-proofing properties even in a severe environment for a long time.

○ Uses The antibacterial nylon resin composition of the present invention is used in a field in which a nylon resin molded product having antifungal, antialgal and antibacterial properties and having no discoloration is required, for example, clothes such as socks and underwear, See
It is particularly effective as textiles such as cloths and towels, bristles of various brushes, various films, powder coatings and hot melt adhesives.

Hereinafter, the present invention will be described more specifically by way of examples.

【Example】

Reference Example 1 [Preparation of antibacterial agent] An aqueous solution of zirconium sulfate and an aqueous solution of ammonium dihydrogen phosphate were mixed at a ratio of zirconium to phosphorus to form a precipitate, and an aqueous solution of sodium hydroxide was prepared. After adjusting the pH to 2 by using, the crystalline zirconium phosphate was obtained by heating in a hydrothermal state at 150 ° C. for 24 hours. The phosphate compound obtained above was added to an aqueous solution of silver nitrate, stirred at room temperature for 4 hours, thoroughly washed with water, dried and pulverized to obtain the following Table 1.
The antibacterial agent shown in was obtained. The obtained antibacterial agent is a white powder having an average particle size of 0.47 μm.

[0036]

[Table 1]

Example 1 [Preparation of antibacterial nylon resin composition and plate] 100 parts of nylon 6 resin pellets, 1 part of the antibacterial agent obtained in Reference Example 1 and 2 parts of acid number titanium, and further various polymers additives _0.3 parts were blended, they were uniformly dry-blended, Meiki Co. injection molding machine M-50AII
By injection molding at 230 ° C. by using DM
A cm × 11 cm × 2 mm antibacterial nylon resin plate was obtained. For comparison, those without the antibacterial agent and the polymer additive and those without the polymer additive were prepared by the same method. The antibacterial nylon resin plate thus obtained and the nylon resin plate of the comparative sample are shown in Table 2 below.

[0038]

[Table 2] Note) * 1: Product name manufactured by Ciba-Geigy Co., Ltd. (hindered amine polymer additive having the structure of the following chemical formula 9) * 2: Product name manufactured by Ciba-Geigy Co., Ltd. (hindered amine polymer additive having the structure of the following chemical formula 10) ) * 3: Ciba-Geigy product name (benzotriazole-based light resistance stabilizer having the structure shown below) * 4: Ciba-Geigy product name (hindered phenolic antioxidant having the structure shown below) Agent)

[0039]

[Chemical 9]

[0040]

[Chemical 10]

[0041]

[Chemical 11]

[0042]

[Chemical 12]

Example 2 [Weather resistance test] Sample No. 1 obtained in Example 1 Nylon resin plates 1 to 6 are manufactured by Toyo Seiki Seisakusho Co., Ltd. Forced deterioration tester UC-1
Was used to measure the weather resistance. The exposure conditions of UC-1 were to repeat ultraviolet irradiation (60 ° C.) and humidification (40 ° C.) alternately every hour, and the exposure time was 6 hours. The colors (L, a, b) before and after the exposure were measured using a color difference meter SZ-Σ80 manufactured by Nippon Denshoku Industries Co., Ltd. The measurement results are shown in Table 3 below.
It was shown to.

[0044]

[Table 3]

As can be seen from Table 3 above, the sample N containing only the nylon resin and containing neither the antibacterial agent nor the polymer additive was used.
Compared to o.1, sample No. 2 containing an antibacterial agent but not containing a hindered amine-based polymer additive, and a sample containing an antibacterial agent and a polymer additive other than a hindered amine-based polymer additive Nos. 5 and 6 were already discolored before the weather resistance test, but Samples Nos. 3 and 4 in which the hindered amine polymer additive was blended with the antibacterial agent were tested before the weather resistance test and after the weather resistance test. , And almost no discoloration occurred.

Example 3 [Antibacterial activity test] Sample No. 1 obtained in Example 1 An antibacterial activity test was conducted on the nylon resin plates 1 to 6 as follows. Escherichia coli is used as the test bacterium, and the nylon resin plate is 5 cm x
The surface was inoculated with a bacterial solution uniformly so that the number of bacteria per 5 cm was 10 ⁵ , and the cells were stored at 36 ° C for 6 hours, and then the surviving bacteria on the test paper piece with a medium for measuring the number of bacteria (SCDLP liquid medium). Was washed out, and this washing solution was used as a test solution. Regarding the test solution, the viable cell count was measured by the pour plate culture method (36 ° C, 2 days) using a culture medium for measuring the number of bacteria, and the nylon resin plate was 5 cm x
It was converted to the viable cell count per 5 cm. The measurement results are shown in Table 4 below.

[0047]

[Table 4]

As can be seen from Table 4, the sample No. 2 to 6 all showed excellent antibacterial properties.

[0049]

EFFECTS OF THE INVENTION The antibacterial nylon resin composition of the present invention and the molded article obtained therefrom have excellent chemical and physical stability, and therefore discoloration hardly occurs. Moreover, it has antifungal, antibacterial and antialgal properties for a long period of time even in a severe environment.

Claims (1)

[Claims] 1. An antibacterial nylon resin composition comprising an antibacterial agent represented by the following general formula [1], a nylon resin and a hindered amine polymer additive. M ¹ _{a Ab} M ² _c (PO ₄ ) _d · nH ₂ O [1] (M ¹ is silver, copper, zinc, tin, mercury, lead, iron, cobalt,
At least one metal ion selected from nickel, manganese, arsenic, antimony, bismuth, barium, cadmium or chromium, A is an alkali metal ion,
At least one ion selected from alkaline earth metal ions, ammonium ions or hydrogen ions,
M ² is a tetravalent metal, n is a number satisfying 0 ≦ n ≦ 6, a and b are positive numbers satisfying la + mb = 1 or la + mb = 2, and c and d are la + mb = 1, c =
2, d = 3, and la + mb = 2, c = 1, d =
It is 2. However, 1 is the valence of M ¹ and m is the valence of A. )