JPH10168265A - Antibacterial vinyl chloride resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an antibacterial resin composition inhibited from being discolored during processing, storage and service by mixing a vinyl chloride resin, a silver-containing inorganic antibacterial agent and a discoloration inhibitor comprising a phosphorous ester compound. SOLUTION: This composition comprises a vinyl chloride resin being a polyvinyl chloride, a copolymer of a vinyl chloride monomer with another monomer such as ethylene, propylene or an alkyl vinyl ether or a blend of a polyvinyl chloride with another polymer, a silver-containing inorganic antibacterial agent represented by the formula (wherein A is at least one member selected among an alkali metal ion, an alkaline earth metal ion, an ammonium ion, and a hydrogen ion; M is a tetravalent ion; n is in the range: 0<=n<=6; a and b satisfy the relationship: a+mb=1; and m is the valence of A), 0.005-10 pts.wt., per 100 pts.wt. polyvinyl chloride resin, photospheres ester compound having at least two phosphorus atoms in the molecule, and optionally a metal oxide such as zinc oxide, titanium dioxide.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a silver-based inorganic antibacterial agent (hereinafter simply referred to as "silver-based antibacterial agent"), a discoloration inhibitor comprising a specific phosphite compound, and a vinyl chloride resin. More specifically, the present invention relates to an antibacterial vinyl chloride resin composition which undergoes very little discoloration during processing, storage and use. The antibacterial vinyl chloride resin molded product obtained from the composition of the present invention is useful as various plastic products requiring antifungal, antialgal and antibacterial properties.

[0002]

2. Description of the Related Art Conventionally, activated carbon,
What supported silver on apatite, zeolite, etc. is known. These are characterized in that they have higher safety than organic antibacterial agents, do not volatilize or decompose, have a long lasting antibacterial effect, and are excellent in heat resistance. Therefore, an antimicrobial resin composition is obtained by mixing these antimicrobial agents and various polymer compounds, and the resin composition is processed into fibrous, film or pellet shapes and used in various applications. .

On the other hand, a conventional phenolic antioxidant, an aliphatic sulfide, and a phenolic antioxidant are used for a conventional vinyl chloride resin composition containing no silver-based antibacterial agent to prevent discoloration during processing, storage and use. It is known to add antioxidants such as disulfides and thiodipropionates, and stabilizers such as fatty acid calcium salts, fatty acid metal salts, epoxy compounds and phosphite compounds.

[0004]

However, the vinyl chloride resin composition containing a silver-based antibacterial agent is more liable to discolor than a composition containing no silver-based antibacterial agent. In some cases, a sufficient discoloration preventing effect cannot be obtained even when a stabilizer or a stabilizer is added, and it has been particularly difficult to prevent discoloration due to light. As an example of preventing discoloration of a vinyl chloride resin composition containing a silver-based antibacterial agent, JP-A-02520361 (JP-A-6-287324) discloses a vinyl chloride resin, a phosphoric acid-based compound as an antibacterial agent, and a stabilizer. A polyvinyl chloride stretch film for food packaging comprising a fatty acid calcium salt and a fatty acid zinc salt is disclosed, but the discoloration preventing effect of this film is still insufficient. The above publication describes that a phosphite compound as an organic stabilizer may be added in addition to the above composition. However, all of the phosphite-based compounds exemplified in the above publications are compounds having only a single phosphorus atom in one molecule (monophosphite). Even with the addition of phyto, a sufficient discoloration preventing effect could not be obtained.

An object of the present invention is to provide a vinyl chloride resin composition containing a silver-based antibacterial agent, wherein the discoloration of the composition during processing, storage and use is suppressed. To provide.

[0006]

Means for Solving the Problems The present inventors have found that a specific phosphite compound is effective as a discoloration inhibitor added to a vinyl chloride resin composition containing a silver antibacterial agent to prevent discoloration. Thus, the present invention was completed.

That is, the antibacterial vinyl chloride resin composition according to claim 1 comprises a vinyl chloride resin, a silver antibacterial agent, and a phosphite compound having two or more phosphorus atoms in one molecule. And a discoloration inhibitor. By using such a specific phosphite compound as a discoloration inhibitor, the composition according to claim 1 has an excellent feature that discoloration is small despite containing a silver-based antibacterial agent.

The antibacterial vinyl chloride resin composition according to claim 2 is characterized in that, in the composition according to claim 1, the silver-based antibacterial agent is represented by the following formula [1]. _{Ag a A b M 2 (PO} 4) 3 · nH 2 O (1) (A is an alkali metal ion, alkaline earth metal ions,
At least one ion selected from ammonium ions or hydrogen ions, M is a tetravalent metal ion,
n is a number satisfying 0 ≦ n ≦ 6, and a and b are both positive numbers satisfying a + mb = 1. Here, m is the valence of A. )

Furthermore, the antibacterial vinyl chloride resin composition according to claim 3 is the composition according to claim 1 or 2, wherein the discoloration inhibitor is liquid at the processing temperature of the vinyl chloride resin. Features. Such a discoloration inhibitor is preferable because it has a good dispersibility in a vinyl chloride resin, so that generation of fish eyes and the like is prevented in a molded article of this composition.

[0010] The antibacterial vinyl chloride resin composition according to claim 4 is the composition according to claim 1, 2 or 3, wherein the discoloration preventing agent is 0 to 100 parts by weight of the vinyl chloride resin. 0.005 to 10 parts by weight.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail. (1) Vinyl chloride resin The “vinyl chloride resin” in the present invention is not limited to polyvinyl chloride, but includes a vinyl chloride monomer and other monomers such as ethylene, propylene, alkyl vinyl ether,
Copolymers with vinylidene chloride, acrylates, methacrylates, vinyl acetate, acrylonitrile, etc.
Or, it is meant to include a blend of polyvinyl chloride and another polymer, and the production method is not particularly limited. Among them, the present invention is particularly useful when the vinyl chloride resin is obtained by emulsion polymerization, for example, when it is in the form of a paste. This is because a vinyl chloride-based resin obtained by emulsion polymerization tends to be more easily discolored by a silver-based antibacterial agent than a resin obtained by bulk polymerization or the like, and a great effect is obtained by the discoloration inhibitor of the present invention.

(2) Silver-based antibacterial agent The "silver-based antibacterial agent" in the present invention is a substance in which silver ions as an antibacterial component are carried on an inorganic substance. Preferred inorganic substances include activated carbon, apatite, zeolite and the like. And aluminosilicates.

Among these, the antibacterial agent suitably used in the present invention is a compound represented by the following formula (1) (hereinafter abbreviated as "antibacterial agent [1]"). _{Ag a A b M 2 (PO} 4) 3 · nH 2 O (1) (A is an alkali metal ion, alkaline earth metal ions,
At least one ion selected from ammonium ions or hydrogen ions, M is a tetravalent metal ion,
n is a number satisfying 0 ≦ n ≦ 6, and a and b are both positive numbers satisfying a + mb = 1. Here, m is the valence of A. )

The antibacterial agent [1] is a crystalline compound belonging to the space group R3c, and each constituent ion forms a three-dimensional network structure. A in the above formula [1] is at least one kind of ion selected from an alkali metal ion, an alkaline earth metal ion, an ammonium ion and a hydrogen ion. Preferred specific examples thereof include alkali metals such as lithium, sodium and potassium. There are ions, alkaline earth metal ions such as magnesium or calcium, and hydrogen ions, and among these, lithium, sodium, ammonium ions and hydrogen ions are preferable ions in view of the stability of the compound and availability at low cost.

M in the above formula [1] is a tetravalent metal ion, and specific examples thereof include a zirconium ion, a titanium ion and a tin ion. In consideration of the safety of the compound, zirconium ion and titanium ion are A more preferred and particularly preferred tetravalent metal ion is a zirconium ion.

Preferred specific examples of the antibacterial agent [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 _0.5 Na _0.25 H _0.25 Zr ₂ (PO ₄ ) ₃ Ag _0.9 Na _0.1 Zr ₂ (PO ₄ ) ₃ Ag _0.7 Na _0.3 Sn ₂ (PO ₄ ) ₃

The method for synthesizing the antibacterial agent [1] used in the present invention includes a baking method, a wet method, a hydrothermal method and the like, and can be easily obtained by these known methods.

In order for the composition of the present invention and the antibacterial resin molded product obtained by molding the same to exhibit fungicide, antibacterial and antialgal properties, the value of a in the above formula [1] is larger. However, when the value of a is 0.001 or more, it is possible to sufficiently prevent mold, exhibit antibacterial properties and anti-algal properties. However, if the value of a is less than 0.01, it will prevent mold,
Since it may be difficult to exert the antibacterial property and the anti-algae property for a long time, it is preferable to set the value of a to a value of 0.01 or more. Also, in consideration of economy, the value of a is 0.7.
The following are appropriate:

A preferred antibacterial agent which has improved the chemical and physical stability of the above antibacterial agent [1] and has a high degree of prevention of discoloration after exposure to heat and light is the antibacterial agent [1], preferably 500
To 1,300 ° C, more preferably 600 to 1,000 ° C, particularly preferably 700 to 900 ° C.

Further, a preferred antibacterial agent [1] having extremely excellent antibacterial properties and weather resistance is obtained by supporting hydrogen ions in the antibacterial agent [1]. When the antibacterial agent [1] has an ammonium ion, it is preferably 600 ° C to 1100 ° C.
By performing the firing step at about 0.5 ° C. for about 0.5 to 2 hours, it is possible to carry hydrogen ions remaining after the ammonium ions are thermally decomposed.

When the antibacterial agent [1] has no ammonium ion or has only a very small amount, the antibacterial agent or a compound which does not carry silver ions thereon (hereinafter abbreviated as "phosphate compound"). By immersing the antimicrobial agent in an acidic solution, the antibacterial agent can support hydrogen ions. Preferred specific examples of the acidic solution immersed for supporting hydrogen ions on the phosphate compound include aqueous solutions such as hydrochloric acid, sulfuric acid, and nitric acid. The acid concentration of the preferred acidic solution is 0.1 N or more, and the preferred treatment Temperature 40 ℃ or more,
The temperature is more preferably 60 ° C. or more and 100 ° C. or less, and the preferred immersion time is 10 minutes or more, more preferably 6 minutes or more.
0 minutes or more.

In order to further enhance the antibacterial properties of the resin composition of the present invention, a specific metal oxide described below may be used together with the antibacterial agent [1]. That is, preferred metal oxides that can be used in the present invention are at least one compound selected from zinc oxide and titanium dioxide. Zinc oxide is represented by a chemical formula of ZnO and is also called zinc white, and may be a natural product or a synthetic product. The titanium dioxide may be either a natural product or a synthetic product, and may be either amorphous or crystalline. Titanium dioxide is classified into anatase, rutile and brookite according to the crystal system.In the present invention, any crystal system may be used, and anatase and rutile are preferred because they can be easily obtained industrially. Things. There are no particular restrictions on the particle size and shape of the metal oxide, but in consideration of the dispersibility in the resin, the average particle size is preferably 10 μm or less, and the shape of the particles is preferably spherical rather than acicular. Those generally used as white pigments can be used.

When the antibacterial agent [1] and the above-mentioned metal oxide are used in combination, a preferable mixing ratio of the metal oxide is 100 parts by weight in total of the antibacterial agent [1] and the metal oxide (hereinafter simply referred to as “parts”). The standard is 5 to 90 parts of metal oxide. If the compounding ratio of the metal oxide is less than 5 parts, it may be difficult to improve the antibacterial activity and exert the effect of preventing discoloration of the resin by using the metal oxide in combination with the antibacterial agent [1]. If the amount is more than 90 parts, it may be difficult to exert the antibacterial effect of the antibacterial agent [1]. In order to exhibit a sufficient antibacterial effect, the silver ion concentration is preferably 0.5% by weight or more, preferably 2% by weight or more based on the total amount of the antibacterial agent [1] and the metal oxide. Is more preferred.

The preferred compounding ratio of the antibacterial agent [1] or a mixture of the antibacterial agent and the metal oxide is 0.01 to 10 parts, more preferably 0.0 to 10 parts, per 100 parts of the vinyl chloride resin.
5 to 5 parts, more preferably 0.1 to 3 parts. If the mixing ratio is less than 0.01 part, the antibacterial property may be insufficient. On the other hand, if the amount is more than 10 parts, the antibacterial activity is hardly improved, but rather the physical properties of the vinyl chloride resin may be deteriorated.

(3) Discoloration inhibitor The "discoloration inhibitor" in the present invention is a phosphite compound having two or more phosphorus atoms in one molecule. Preferred phosphites are diester or triester esters, preferred diesters include dialkyl esters, diaryl esters and alkylaryl esters, and preferred triesters are trialkyl esters, dialkylaryl esters,
There are diarylalkyl esters and triarylesters. Representative examples of phosphite compounds having two or more phosphorus atoms in one molecule include bisphenol A diphosphite represented by the following formula (1) and analogs thereof, and compounds represented by the following formula (2): Pentaerythritol diphosphite, oligoether diphosphite represented by the following formula (3), and the like.

[0026]

Embedded image (However, R ¹ , R ² , R ³ and R ⁴ are each a hydrocarbon group having 1 to 18 carbon atoms, preferably a hydrocarbon group having 6 to 18 carbon atoms, and more preferably an alkyl group having 10 to 18 carbon atoms. hand,
R ^{1 to} R ⁴ may be the same or different groups. R ⁵ is an alkylene group having 1 to 9 carbon atoms, preferably 1 to 7 carbon atoms, and more preferably 1 to 4 carbon atoms.
R ⁶ , R ⁷ , R ⁸ , and R ⁹ are H or an alkyl group having 1 to 6 carbon atoms, and R ^{6 to} R ⁹ may be the same or different groups. )

[0027]

Embedded image (However, R ¹ and R ² are a hydrocarbon group having 1 to 18 carbon atoms,
It is preferably a hydrocarbon group having 6 to 18 carbon atoms, more preferably a hydrocarbon group having 10 to 18 carbon atoms, wherein R ¹ and R ²
May be the same or different groups. )

[0028]

Embedded image (However, R ¹ , R ² , R ³ and R ⁴ are a hydrocarbon group having 1 to 20 carbon atoms, preferably a hydrocarbon group having 6 to 18 carbon atoms, more preferably a hydrocarbon group having 10 to 18 carbon atoms. So,
R ^{1 to} R ⁴ may be the same or different groups. R ⁵ is an alkylene group having 1 to 9 carbon atoms, preferably 1 to 7 carbon atoms, more preferably 1 to 4 carbon atoms, and n is 1 to 6, preferably 2 to 4. )

Commercial products of bisphenol A diphosphite and its analogs include “Adeka Stub 1500” and “Adeka Stub 260” manufactured by Asahi Denka Kogyo Co., Ltd., and commercially available products of pentaerythritol diphosphite are those manufactured by Asahi Denka Kogyo Co., Ltd. Product name "ADK STAB PEP-4
C, ADK STAB PEP-8, ADK STAB P
EP-24G "and" ADEKA STAB PEP-36 ". As a commercially available product of triphosphite, there is a product name “ADEKA STAB 522A” manufactured by the company.

As the discoloration inhibitor in the present invention, it is preferable to use a compound which becomes liquid at the processing temperature of the vinyl chloride resin. Specifically, when the vinyl chloride resin is mainly composed of polyvinyl chloride, the melting point of the discoloration inhibitor is preferably 200 ° C. or less, more preferably 160 ° C. or less,
More preferably, the temperature is 100 ° C. or lower. A compound having a melting point of more than 200 ° C. can be used as long as the compound has good dispersibility in a vinyl chloride resin. However, if the compound has insufficient dispersibility, the compound of the present invention may be molded. There is a possibility that fish eyes etc. may occur in the product.

The preferred compounding ratio of the discoloration inhibitor in the present invention is 0.005 to 100 parts per 100 parts of the vinyl chloride resin.
It is 10 parts, more preferably 0.01 to 5 parts, still more preferably 0.05 to 3 parts, particularly preferably 0.1 to 2 parts. If the compounding ratio of the discoloration inhibitor is less than 0.005 parts, the discoloration of the vinyl chloride resin composition may not be sufficiently prevented. On the other hand, if the amount exceeds 10 parts, the discoloration preventing effect is hardly improved, and the physical properties of the vinyl chloride resin may be reduced.

Further, in addition to the discoloration inhibitor of the present invention, an inorganic ion exchanger can be used in combination with the discoloration inhibitor, and a lubricant, a dispersant, a pigment, a surface modifier and a discoloration inhibitor of the present invention can be used. May be used in combination. The inorganic ion exchanger is not particularly limited, and any of positive, negative and amphoteric ion exchangers can be used, but a cation type or anion type inorganic ion exchanger is preferable. Specific examples include zirconium phosphate [H ₂ Zr (PO ₄ ) ₂ ], zirconium phosphate [HZr ₂ (PO ₄ ) ₃ ], antimony trioxide, antimony pentoxide, hydrous titanium oxide, hydrous zirconium oxide, aqueous oxynitrate There are bismuth oxide, hydroxyapatite, aluminum silicate and the like, and a particularly preferred specific example is aluminum silicate. When these discoloration prevention assistants are used, the preferred compounding ratio is 0.005 to 10 parts, more preferably 0.01 to 5 parts, per 100 parts of the vinyl chloride resin. Further, a preferable mixing ratio of the discoloration inhibitor and the auxiliary is such that the amount of the auxiliary is 0 to 70 parts based on 100 parts in total of the discoloration inhibitor and the auxiliary.

As described above, it is already known to blend monophosphite as a stabilizer or antioxidant for vinyl chloride resins. However, the relationship between the type of the phosphite-based compound to be added to the vinyl chloride-based resin containing a silver-based antibacterial agent and its discoloration preventing effect has not been known. The present inventors have found that, in a vinyl chloride resin containing a silver antibacterial agent, a specific phosphite compound having "two or more phosphorus atoms in one molecule" is significantly superior to monophosphite. This fact is extremely surprising.

(4) Other Components In the antibacterial vinyl chloride resin composition of the present invention, it is preferable to add a stabilizer in addition to the above essential components. As the stabilizer, a conventionally known stabilizer used for a vinyl chloride resin containing or not containing an antibacterial agent may be appropriately selected and used. Suitable stabilizers in the present invention are those which use a fatty acid calcium salt and a fatty acid zinc salt in combination. The preferable addition amount is in a range where the total amount of the fatty acid calcium salt and the fatty acid zinc salt is 0.05 to 5 parts, more preferably 0.1 to 2 parts, based on 100 parts of the vinyl chloride resin. If the addition amount is less than 0.05 part, the composition of the present invention is difficult to mold and may be easily discolored. On the other hand, if the added amount exceeds 5 parts, the effect of improving thermal stability cannot be obtained, but rather there is a problem that physical properties, workability and the like are reduced. The ratio of the fatty acid calcium salt and the fatty acid zinc salt is about the same amount or the ratio that the fatty acid zinc salt is about 15 parts to about 10 parts of the fatty acid calcium salt. Is preferred.

Further, in addition to the above-mentioned stabilizer composed of the fatty acid calcium salt and the fatty acid zinc salt, another stabilizer such as an epoxy stabilizer may be used. Epoxy stabilizers include epoxidized vegetable oils, such as epoxidized soybean oil, epoxidized linseed oil, and epoxy resins. Further, in addition to the "phosphite compound having two or more phosphorus atoms in one molecule" as a discoloration inhibitor, which is an essential component of the present invention, an organic stabilizer such as monophosphite is added to a heat dissipating agent. It can be used as a stabilizer or a storage stabilizer.
The amount is 0.01 to 10 parts by weight, more preferably 0.05 to 5 parts by weight, based on 0 parts. Further, an organic stabilizer made of another organic acid or an organic acid ester, or a metal stabilizer may be used.

In addition, the composition of the present invention may optionally contain a plasticizer, an antifogging agent, an antioxidant, an antistatic agent, an ultraviolet absorber, a lubricant and the like. Moreover, you may mix | blend metal soap etc. as needed.

As the plasticizer, di-n-octyl phthalate, di-2-ethylhexyl phthalate, dibutyl phthalate, diisononyl phthalate, butyl benzyl phthalate, dilauryl phthalate, diheptyl phthalate, dimethyl phthalate, diisodecyl phthalate, dioctyl phthalate, dicyclohexyl Phthalates such as phthalate, dioctyl adipate, diisodecyl adipate, diisononyl adipate (referred to as DINA), di (n-hexyl, n-octyl, n-decyl) having a linear alkyl group having 6, 8, or 10 carbon atoms Adipates, adipic acids such as di (i-heptyl, i-nonyl) adipates having a straight-chain and / or side-chain alkyl group having 7 or 9 carbon atoms, and azelaic acids such as di-i-octyl azelate The Benzoic acid such as diethylene glycol benzoate, fumaric acid such as dibutyl fumarate, dioctyl fumarate, diphenoxyethyl fumarate, lauric acid such as butyl laurate, ethylene glycol monoethyl ether laurate, and pentaerythritol tetraacetate Pentaerythritol, acetylsilinoleate, etc., silinol, dimethyl sebacate, etc., sebacic acid, acetyltributyl citrate, etc., citric acid, glyceryl monolauryl diacetate, etc., glycerin esters, and other polyesters. Can be The plasticizer used in the present invention is used for imparting flexibility to a molded article and is not limited in the amount of addition, but is preferably 10 parts or more based on 100 parts of the vinyl chloride resin.

As the lubricant, isostearic acid,
Fatty acid lubricants such as stearic acid and palmitic acid; fatty acid amide lubricants such as stearic acid amide and methylenebisstearamide; ester lubricants such as butyl stearate; polyethylene wax; liquid paraffin; and higher alcohols.

Examples of the antioxidant include phenolic antioxidants, aliphatic sulfides, disulfides, thiodipropionates, and the like. In the present invention, an antifogging agent may be further added according to the purpose of use. As the anti-fog agent, glycerin esters, polyethers, and the like can be used.

(5) Molding The antibacterial vinyl chloride resin composition of the present invention can be molded into various forms using any known processing techniques and machines. Examples of specific molding methods include extrusion molding, injection molding, calendering, vacuum molding and foam molding.

Further, after preparing a granular material (masterbatch) from the composition of the present invention in which the silver-based antibacterial agent and the discoloration inhibitor of the present invention are contained in a vinyl chloride-based resin at a high concentration, the vinyl chloride-based resin is prepared. It is also possible to mix and mold. When preparing a master batch composed of a vinyl chloride-based resin containing a silver-based antibacterial agent and a discoloration inhibitor in a high concentration, there is no limitation on the order in which these components are mixed. A plurality of types of master batches having different components, such as a master batch composed of a master batch and a master batch composed of a discoloration inhibitor and a vinyl chloride-based resin, may be mixed and molded.

The preferred compounding ratio of the silver-based antibacterial agent in the master batch is 70/100 parts of the vinyl chloride-based resin.
Parts or less, more preferably 50 parts or less. 70
Even if it is blended beyond the limit, the antibacterial property of the resin molded article is hardly further improved, and it is difficult to obtain a master batch by molding a mixture comprising a silver-based antibacterial agent, a discoloration inhibitor and a vinyl chloride-based resin. There is a risk of becoming. Further, a preferable mixing ratio of the discoloration inhibitor in the master batch is 50 parts or less, more preferably 30 parts or less per 100 parts of the vinyl chloride resin.

The shape and size of the masterbatch are not particularly limited, and specific shapes include a sphere, a prism, a column, and a disk. In order to facilitate the subsequent molding step, it is preferable that the master batch and the vinyl chloride resin have similar shapes and sizes. Generally, cylindrical pellets having a diameter and length of 1 to 5 mm are preferred.

As a processing method for obtaining a master batch composed of a silver-based antibacterial agent and / or a discoloration inhibitor and a vinyl chloride-based resin, any of known methods can be employed.
A method in which a silver-based antibacterial agent and / or a discoloration inhibitor are mixed with a vinyl chloride-based resin in a Henschel mixer and then formed into a pellet by an extrusion molding machine. Mix directly into
There is a method of molding into a pellet by an extrusion molding machine.

The antibacterial vinyl chloride resin molded article obtained as described above has a fungicidal, antibacterial and antialgal property, and a specific phosphite, when a silver-based antibacterial agent is blended. The compound is excellent in preventing discoloration at the time of molding, storage, or use by being mixed.

(6) Use The antibacterial vinyl chloride resin molded article molded using the composition of the present invention needs antibacterial properties, anti-algae and fungicidal properties, and various types of vinyl chloride resin molded articles are used. It is useful in the field. Specific applications include, for example, various molded articles such as pipes and boards, flooring materials, wall materials, furniture members, piping, piping materials and other building materials, films, sheets, wraps, synthetic leather, electric wires, and the like. Coating materials, housing materials for mixers, VTRs, televisions, etc., watches, cameras, stereos, tape recorders, OA equipment, telephones,
There are various containers, sports goods, daily necessities, kitchen utensils such as tableware etc. for facsimile equipment and other vehicles and interior goods related to miscellaneous goods. Also, for stationery related goods, there are mechanical pencils, ballpoint pens, erasers, clips, staples, clear cases, etc. is there.

[0047]

The present invention will be described below more specifically.

(Experimental Example 1) First, a substance having an effect of preventing discoloration was examined. The additives used in the study are as follows. SC102; Tris (nonylphenyl) phosphite (trade name “ADK STAB SC1” manufactured by Asahi Denka Kogyo Co., Ltd.)
02 ") 1500; bisphenol A tetra-C _12-15 alkyl diphosphite (trade name" ADEKA STAB 1500 "O-130P, manufactured by Asahi Denka Kogyo Co., Ltd.); Epoxidized soybean oil (trade name" ADEKA "manufactured by Asahi Denka Kogyo Co., Ltd. Sizer O-130P ")

The amounts of the silver-based antibacterial agents shown in Table 1 or the above-mentioned additives were mixed with the following base composition (referred to as vinyl chloride resin composition a-1) to obtain an antibacterial vinyl chloride resin composition. Products a-2 to a-7 were prepared. Silver zirconium phosphate (trade name “NOVALON AG100” manufactured by Toagosei Co., Ltd.) was used as the silver-based antibacterial agent. [Base composition] Paste PVC resin 100 parts Dioctyl phthalate 50 parts Epoxidized soybean oil 5 parts Calcium stearate 0.2 parts Zinc stearate 0.2 parts

The discoloration of the obtained antibacterial vinyl chloride resin composition was evaluated. Table 1 shows the results.

[0051]

[Table 1]

Each evaluation shown in Table 1 was performed by the following methods. * 1: Thermal stability A change in color tone when heated and molded in an oven at 200 ° C. for 5 minutes was confirmed. * 2: Storage stability A change in color tone when the prepared composition was allowed to stand in a room for 10 days was confirmed. * 3: Weather resistance (outdoor exposure for 3 days) The molded article obtained in the above test * 1 was exposed to the outdoor for 3 days. * 4: Weather resistance (weather resistance tester for 3 hours)
Irradiation with an ultraviolet fluorescent lamp was performed at 60 ° C. for 3 hours. As a weather resistance tester, "UC-1" manufactured by Toyo Seiki Seisaku-sho, Ltd. was used. * 5: Weather resistance (indoor exposure for 4 days) The molded article obtained by the above test * 1 was exposed to indoors for 4 days.
In the tests * 1 to * 5, the degree of color tone change was indicated in three stages of （(good)>△> × (bad). * 6: Color difference color difference meter (manufactured by Nippon Denshoku Industries Co., Ltd., color difference meter SZ-II)
80) was used to measure the color (L, a, b). Also,
The color difference ΔE was determined by comparing the color of the molded article immediately after molding by the method of * 1 with the color after performing the weather resistance test of * 5 on the molded article.

As shown in Table 1, the compositions a-2 and a-3 in which 0.5 part and 1.0 part of the antibacterial agent were added to the composition a-1 (blank) to which the antibacterial agent was not added. Showed significant discoloration in the weather resistance tests * 3 to * 5. In compositions a-4 and a-5 to which tris (nonylphenyl) phosphite, which is a monophosphite, was added, the discoloration was substantially the same as in a-2 and a-3 in which the antibacterial agent addition amounts were equal. That is, even if monophosphite was added, discoloration due to the antibacterial agent could not be prevented. Further, the discoloration preventing effect was not obtained even in composition a-7 to which epoxidized soybean oil was added.

On the other hand, the composition a-6 using the bisphenol A tetra-C _12-15 alkyl diphosphite which is a discoloration inhibitor in the present invention has all of heat stability, storage stability and weather resistance. It was equal to or higher than the composition a-1. That is, it can be seen that the discoloration was prevented by the addition of diphosphite even though the composition a-6 contained 1.0 part of the antibacterial agent.

(Experimental Example 2) Next, the anti-tarnish agent "ADK STAB 1500" used in Experimental Example 1 was added to the antibacterial agent 0.5
The suitable amount of addition to the composition containing parts was studied. Table 2
The amount of the silver-based antibacterial agent or the additive described above was mixed with the same base composition a-1 as in Experimental Example 1 to prepare antibacterial vinyl chloride resin compositions b-2 to b-8. The evaluation of discoloration was performed in the same manner as in Experimental Example 1. However, the color difference test of * 6 was performed on the molded product immediately after molding by the method of * 1 and the molded product after the weather resistance test of * 3. Table 2 shows the results.

[0056]

[Table 2]

As can be seen from Table 2, the composition b containing 0.1 to 0.5 part of the discoloration inhibitor was compared with the composition b-2 containing 0.5 part of the antibacterial agent and not containing the discoloration inhibitor. -3 to b-7
In each case, the discoloration is improved. That is, in the composition b-3 to which 0.1 part of the discoloration inhibitor was added, the discoloration was suppressed to the same degree as that of the composition a-1 (blank) which did not contain the antibacterial agent despite containing the antibacterial agent. Discoloration inhibitor
In the compositions b-4 to b-7 to which 2 or more parts were added, a discoloration prevention effect equal to or higher than that of the blank was obtained.

(Experimental Example 3) A composition c- having the same material and composition as the composition b-5 except that the following compound was added in place of the discoloration inhibitor "ADK STAB 1500" used in Experimental Example 1. 2-c-4 were prepared. Composition c-2; pentaerythritol dialkyl diphosphite (trade name “ADK STAB PEP-8” manufactured by Asahi Denka Kogyo Co., Ltd.) Composition c-3; pentaerythritol diaryl diphosphite (manufactured by Asahi Denka Kogyo Co., Ltd., product Name "ADK STAB PEP-4C") Composition c-4; dipropylene glycol diphosphite (trade name "JPP100" manufactured by Johoku Chemical Co., Ltd.)

The discoloration properties of these compositions were evaluated in the same manner as in Experimental Example 2, and compared with Composition a-2 containing the same amount of the antibacterial agent. Was suppressed.

It should be noted that the present invention is not limited to the specific embodiments described above, but can be variously modified within the scope of the present invention according to the purpose and application.

[0061]

The composition of the present invention is an antibacterial vinyl chloride resin composition having fungicidal, antibacterial and antialgal properties due to the incorporation of a silver-based antibacterial agent. When the specific phosphite compound is blended, the discoloration preventing effect during molding, storage, or use is excellent. Therefore, this composition is useful as a material for various plastic products requiring antifungal, antialgal and antibacterial properties.

Claims (4)

[Claims] 1. A discoloration inhibitor comprising a vinyl chloride resin, a silver inorganic antibacterial agent, and a phosphite compound having two or more phosphorus atoms in one molecule. Antibacterial vinyl chloride resin composition. 2. The antibacterial vinyl chloride resin composition according to claim 1, wherein the silver-based inorganic antibacterial agent is represented by the following formula [1]. _{Ag a A b M 2 (PO} 4) 3 · nH 2 O (1) (A is an alkali metal ion, alkaline earth metal ions,
At least one ion selected from ammonium ions or hydrogen ions, M is a tetravalent metal ion,
n is a number satisfying 0 ≦ n ≦ 6, and a and b are both positive numbers satisfying a + mb = 1. Here, m is the valence of A. ) 3. The antibacterial vinyl chloride resin composition according to claim 1, wherein the discoloration inhibitor is liquid at a processing temperature of the vinyl chloride resin. 4. The antibacterial vinyl chloride resin composition according to claim 1, wherein the discoloration inhibitor is added in an amount of 0.005 to 10 parts by weight based on 100 parts by weight of the vinyl chloride resin.