JP2000290109A - Antibacterial agent for silicone resin - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prepare an antibacterial agent for a silicone resin by including a specific organopolysiloxane, capable of imparting a permanent antistatic power and/or an antibacterial characteristic when internally added to the silicone resin in a small amount without imparting the intrinsic properties of the silicone resin. SOLUTION: This antibacterial agent for a silicone resin is prepared by including an organopolysiloxane having an unit containing a cationic group in its molecule, expressed preferably by formula I [wherein, R is a monovalent hydrocarbon; (m) and (n) are each 0-1,000 with proviso that (m) and (n) are not 0 at the same time; X-Z are each a group of formula II or the like; R1, R4 are R7 are each a molecular chain consisting of a divalent organic group selected from a (poly)oxyalkylene; R2, R3, R5, R6 and R8-R10 are each a monovalent hydrocarbon capable of having OH substituent; W- is an anion; (a) and (b) are each 0-100 with proviso that (a) and (b) are not 0 at the same time]. The agent is useful as incorporation one into silicone resin products such as silicone foam, a silicone sealant, silicone rubber or the like.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to an antibacterial agent for a silicone resin.

[0002]

2. Description of the Related Art At present, silicone resin products are widely used in various applications in various industrial fields. In general, a silicone resin is excellent in physical properties such as heat resistance, cold resistance, electrical insulation, chemical resistance, water repellency, and releasability, as well as beautiful in appearance and easy to mold. However, on the other hand, due to the high electrical insulation, friction etc.
It has the drawback of easily generating and accumulating static electricity. That is, due to the accumulation of the static electricity, dust and dirt adhere to the product, causing a problem such as impairing the appearance and reducing the production capacity during the processing and forming process. In addition, noise due to static electricity of a silicone resin product used in the field of electronics in recent years or breakage of IC parts has become an important problem.

Heretofore, as a method for preventing electrification of a silicone resin product, a method of internally adding or surface-coating a cationic, anionic or amphoteric ionic surfactant or a nonionic surfactant, carbon black, metal powder ,
A method of adding a filler-like conductive agent such as a peroxide-based conductive agent is known.

On the other hand, as a method for imparting antimicrobial properties to silicone resin products, metal ions such as silver ions, copper ions, and zinc ions are supported on zeolite, ceramics, silica gel, glass, carbon fibers, and viscous minerals such as smectite. A method of internally adding an antimicrobial agent to a silicone resin is known.

[0005]

However, in the former method of preventing electrification of a silicone resin product, an activator added or applied over time bleeds out from the surface of the resin molded product, and the water is washed or washed. There is a fatal drawback that the antistatic ability gradually decreases due to wiping, and in the latter case, the obtained conductivity is large, and the durability and durability of the conductive performance are remarkably excellent, There are problems that it must be incorporated in a large amount in the resin, that the cost of antistatic is relatively high, and that the original physical properties such as water resistance and toughness of the resin are deteriorated.

In the method of internally adding an antibacterial agent in which metal ions are supported on zeolite or the like in order to impart antibacterial properties to a silicone resin product, the dispersibility of the antibacterial agent is insufficient. However, there are problems such as bleed-out, chalking of the resin surface to impair the aesthetic appearance, and relatively high cost.

[0007] The present invention provides an antibacterial agent capable of imparting permanent antistatic properties and / or antibacterial properties by adding a small amount to a silicone resin internally without impairing the inherent properties of the silicone resin. It is intended to be.

[0008]

Means for Solving the Problems As a result of intensive studies, the present inventors have completed an antibacterial agent which can solve the above problems. That is, the present invention is an antibacterial agent for a silicone resin, comprising an organopolysiloxane having a portion containing a cationic group in a molecule.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION In the antibacterial agent according to the present invention,
Cationic groups such as quaternary ammonium bases and quaternary phosphonium bases exert an antibacterial action by adsorbing to the cell membrane of bacterial cells and inhibiting physiological actions. By repeatedly arranging a plurality of ionic groups in a portion containing a cationic group in a molecule with a nonionic molecular chain interposed therebetween, it is possible to achieve high antibacterial activity based on an increase in active group density. In addition, the organopolysiloxane moiety has effects such as increasing the chemical affinity with the silicone resin, reducing the tendency of bleed-out, reducing toxicity, and reducing mucous membrane irritation.

The cationic group includes a primary amine salt,
Examples include groups such as secondary amine salts, tertiary amine salts, quaternary ammonium salts, and quaternary phosphonium salts. Examples of the counter ion of the cationic group include a halogen ion, a sulfate ion, a methyl sulfate ion, an ethyl sulfate ion, a methyl carbonate ion, and a carboxylate ion. Preferred among these cationic groups are quaternary ammonium bases and quaternary phosphonium bases.

The nonionic molecular chain may be a molecular chain composed solely of a divalent organic group or a divalent molecular chain having a plurality of divalent organic groups bonded thereto. Examples of the divalent organic group include a divalent hydrocarbon group [alkylene group (methylene group, ethylene group, etc.), part of an aromatic ring structure (phenylene group, etc.), and part of a non-aromatic ring structure (cyclohexylene group, etc.). 2) containing a nitrogen and / or oxygen atom
Organic group [ether group, carbonyl group, ester group,
Amido group, urethane group, urea group] itself or a divalent organic group containing these groups [eg, -CH ₂ CH _{2
CO -, - CH 2 CH 2} COO -, - CH 2 CONH 2 -,
_{-CH 2 CH 2 CH 2 O -} , - CH 2 CONHCH 2 CH
_{2 -, - CH 2 NHCONHCH 2} - , etc.], groups of the nitrogen or oxygen atom-containing heterocyclic structure include (poly) oxyalkylene group. In a divalent molecular chain in which a plurality of divalent organic groups are bonded, the divalent organic groups may be the same or different. The portion containing the ionic group may be located on the side chain or main chain in the organopolysiloxane molecule, or may be located on both the side chain and the main chain. In the portion containing the ionic group, the nonionic molecular chain is located at the bonding portion with the polysiloxane skeleton.

Examples of suitable compounds among the organopolysiloxanes having a cationic group in the molecule of the present invention include compounds represented by formula (C).

[0013]

Embedded image

Wherein R is a monovalent hydrocarbon group, m and n are integers of 0 to 1000 (however, m and n are not simultaneously 0), and X, Y and Z are A group represented by either formula (D) or (E) or R (each may be the same or different, and not all R). ]

[0015]

Embedded image

Wherein R ¹ , R ⁴ and R ⁷ are a divalent hydrocarbon group, an ether group, a carbonyl group, an ester group, an amide group, a divalent organic group containing a urethane group or a urea group, nitrogen, Or, a molecular chain composed solely of a divalent organic group selected from the group consisting of a group having an oxygen atom-containing heterocyclic structure and a (poly) oxyalkylene group, or a divalent molecular chain in which a plurality of such divalent organic groups are bonded. , R ² , R ³ , R ⁵ , R ⁶ ,
R ⁸ , R ⁹ and R ¹⁰ are a monovalent hydrocarbon group which may be substituted with a halogen or a hydroxyl group (each may be the same or different), W ⁻ is an anion, and a and b are integers of 0 to 100 (However, a and b do not become 0 at the same time.) ]

[0017]

Embedded image

Wherein R ¹ , R ⁴ and R ⁷ are a divalent hydrocarbon group, an ether group, a carbonyl group, an ester group, an amide group, a divalent organic group containing a urethane group or a urea group, nitrogen, Or, a molecular chain composed solely of a divalent organic group selected from the group consisting of a group having an oxygen atom-containing heterocyclic structure and a (poly) oxyalkylene group, or a divalent molecular chain in which a plurality of such divalent organic groups are bonded. , R ² , R ³ , R ⁵ , R ⁶ ,
R ⁸ , R ⁹ and R ¹⁰ are a monovalent hydrocarbon group which may be substituted with a halogen or a hydroxyl group (each may be the same or different), W ⁻ is an anion, and a and b are integers of 0 to 100 (However, a and b do not become 0 at the same time.) ]

In the compound (C), examples of the monovalent hydrocarbon group R in the formula include an alkyl group such as a methyl group, an ethyl group and a propyl group, an aryl group such as a phenyl group, and an aralkyl group such as a benzyl group. Examples thereof include a lower alkyl group such as a methyl group and an ethyl group and a phenyl group, and a methyl group is particularly preferable.

The groups represented by the general formulas (D) and (E)
In the formula, the divalent organic molecular chain R ¹, R^FourAnd R
⁷Is a two-valent organic group
It may be a divalent molecular chain in which a plurality of organic groups are bonded. Divalent
The organic group includes a divalent hydrocarbon group [alkylene group (methyl
Group, ethylene group, etc.), part of the aromatic ring structure (phenylene
A part of the non-aromatic ring structure (cyclohexyl)
Group, vinylene group, etc.), nitrogen and / or acid
Divalent organic group containing an elemental atom [ether group, carbonyl
Group, ester group, amide group, urethane group, urea
Group], a group having a heterocyclic structure containing a nitrogen or oxygen atom,
Li) oxyalkylene groups.

In the groups represented by the general formulas (D) and (E), R ² , R ³ , R ⁵ , R ⁶ , R ⁸ , R ⁹ and R
¹⁰ is a halogen, a methyl group, an ethyl group, a propyl group, an n-butyl group, an n-octyl group, an n-decyl group, an n-lauryl group, an n-stearyl which may have a substituent such as a hydroxyl group. Examples include an alkyl group such as a group, an aryl group such as a phenyl group, and a monovalent hydrocarbon group such as an aralkyl group such as a benzyl group.

[0022] In the group represented by the general formula (D) and (E), the anion W ^- as a chlorine ion, a bromine ion, a halogen ion such as iodide ion, hydroxide ion, sulfate ion, methylsulfate ion, ethyl Examples thereof include a sulfate ion, a hydrogen sulfate ion, a sulfite ion, a carbonate ion, a methyl carbonate ion, an ethyl carbonate ion, a nitrate ion, a carboxylate ion, a sulfonate ion, and a phosphonate ion.

The type of silicone resin product to which the antimicrobial agent of the present invention is to be internally added is not particularly limited, and examples thereof include silicone foam, silicone sealant, silicone rubber, silicone liquid rubber, silicone varnish, and the like. Is done.

The antimicrobial agent of the present invention is effective when it is added and compounded at any stage during the production process of a silicone resin product. The method of internal addition and blending is not particularly limited, and examples thereof include a method of heating and mixing with a kneader, a roll, or the like. The antibacterial agent is used so that the compounding amount with respect to the resin is preferably 0.1 to 10% by weight. If the amount is too small, the effect is insufficient, and if the amount is too large, the physical properties and appearance of the resin may be impaired.

The antibacterial agent of the present invention can be used in combination with a surfactant type antistatic agent or a filler-like conductive material. Also, additives for ordinary silicone resins, such as plasticizers,
Additives such as a flame retardant, an antioxidant, and a coloring agent may be used in combination.

[0026]

The present invention will be further described with reference to the following examples.
The present invention is not limited to this. In the following, parts indicate parts by weight. Production Example 1 750 g of a mixture of 400 g of an amino-modified silicone represented by the following formula 7 and 250 g of dimethyl carbonate
Was dissolved in isopropyl alcohol, and the temperature was raised to 130 ° C. to perform a quaternization reaction for 48 hours. After the reaction, isopropyl alcohol, dimethyl carbonate, methanol generated by the reaction, and carbon dioxide were distilled off under reduced pressure to obtain an organopolysiloxane <1> containing a quaternary ammonium base in the side chain. The quaternary ammonium base concentration of compound <1> was 0.86 meq / g.

[0027]

Embedded image

Production Example 2 A polyethylene glycol 300 (PEG30) was placed in a reaction vessel.
0; 299.8 g of number average molecular weight (295), 270 g of sodium 3-sulfoisophthalate (SIP) and 0.7 g of dibutyltin oxide as an esterification catalyst were stirred and heated to 190 ° C. under reduced pressure of 5 mmHg.
Thereafter, an esterification reaction was carried out at 190 ° C. for 6 hours while distilling off water produced. Intermediate of PEG: SIP = 3: 3 (PEG-SIP-PEG-SIP-PEG-SI
P) was obtained. 100 g of an epoxy-modified silicone mixture represented by the following chemical formula 8 was added thereto,
The reaction was carried out for an hour to obtain an organopolysiloxane <2> containing a sulfonate group in the side chain. Compound <2> had a sodium sulfonate base concentration of 1.87 meq / g.

[0029]

Embedded image

Production Example 3 400 g of the amino-modified silicone mixture represented by the following formula (9) was dissolved in 320 g of toluene in a reaction vessel, and then 12 g of sodium hydroxide was added. 14 at room temperature
After dropping 0 g of dimethyl sulfuric acid, the temperature was raised to 70 ° C,
The quaternization reaction was performed for 4 hours. After the reaction, the solid components were filtered off, and then toluene was distilled off to obtain an organopolysiloxane <3> containing a quaternary ammonium base in the side chain. The quaternary ammonium base concentration of compound <3> is 2.
It was 51 meq / g.

[0031]

Embedded image

Production Example 4 In a reaction vessel, 400 g of a mixture of a carbinol-modified silicone represented by the following formula and 2 g of boron trifluoride diethyl ether complex were dissolved in 320 g of toluene. After 325 g of epichlorohydrin was added dropwise at room temperature to carry out a cationic polymerization reaction, toluene was distilled off. An intermediate in which an average of four molecules of epichlorohydrin oligomer were bonded to both ends of the mixture of Chemical formula 10 was obtained. This intermediate was added dropwise to a solution of 850 g of tributylphosphine in 500 ml of toluene at room temperature under a nitrogen atmosphere, and the mixture was heated and reacted under reflux for 20 hours. The organophosphate containing a quaternary phosphonium base at both terminals was obtained. Polysiloxane <4> was obtained. The quaternary phosphonium base concentration of compound <4> is 2.
72 meq / g.

[0033]

Embedded image

Example (1) Silicone liquid rubber (KE-108 manufactured by Shin-Etsu Chemical Co., Ltd.) and curing agent (CA manufactured by Shin-Etsu Chemical Co., Ltd.) in the proportions shown in Table 1
T-108) and <1> and <2> of the present invention (Examples 1 to 3).
3) each was mixed for 5 minutes with a mixer,
It was applied to a 0 μm polyester film using a bar coater. It was left at room temperature for 24 hours or more, cured and dried to obtain a test sheet. The thickness of the formed coating film is about 1μ
m. In the same manner, a quaternary ammonium salt type surfactant having no organopolysiloxane skeleton <5> [Cation DDC-50 (didecyldimethylammonium chloride, manufactured by Sanyo Chemical Industries, Ltd., quaternary ammonium base concentration: 2. (30 meq / g)]] (Comparative Example 1) and a test sheet without the antistatic agent (Comparative Example 2) were also prepared. The specific surface resistance of the coated surface of each test sheet was measured, and the antistatic property was evaluated. Next, each test sheet was immersed in water at 30 ° C. for 16 to 24 hours. The test sheet taken out was wiped with a cloth and dried, and then the surface resistivity was measured again.

[0035]

[Table 1] Examples 1 to 3 all exhibited good antistatic effects even when added in small amounts. The antistatic effect was not lost by immersion in water or wiping with a cloth.

Example (2) An antibacterial effect test was conducted on the antibacterial agents <3> and <4> of the present invention. The types of the strains used in the test, their methods and results are shown below. As a comparative example, a test was carried out on Ag / zeolite (manufactured by Bactekiller, Kanebo) in the same manner.

Bacterial strains used The following three types of bacteria which were seriously hindered in industry were selected. Ec: Escherichia coli IFO 3301 Sa: Staphylococcus aureus IFO 12732 Pa: Pseudomonas aeruginose IAM 1054

Test method (Test for antibacterial activity) The bactericidal activity of the antibacterial agent composition according to the present invention was examined by measuring the minimum inhibitory concentration (MIC) of the Japanese Society of Chemotherapy. That is, a bacterial solution diluted and adjusted so that the number of bacteria becomes 10 ⁶ CFU / ml was inoculated on a drug-poured agar plate, and then inoculated.
After culturing at 7 ° C for 18 to 20 hours, the MIC was defined as the minimum concentration of the drug that inhibited the growth of the test bacteria. (Bleed-out resistance) 85 parts of KE-108 and 5 parts
Parts of CAT-108 and <3 as antibacterial agent of the present invention
> And <4> (Examples 4 and 5) were each mixed for 5 minutes with a mixer and poured into a mold (5 cm × 5 cm × 2 cm). It was left at room temperature for one week or longer, cured and dried to obtain a test piece. In the same manner, a test piece was prepared for a sample to which silver zeolite <6> (Bakutekira, manufactured by Kanebo) was added as an antibacterial agent (Comparative Example 3). After holding each test piece at 70 ° C. for 2 weeks, the bleed out property of the test piece surface was evaluated by finger touch and visual observation according to the following criteria. ◎: No bleed-out △: Slight bleed-out ×: Large amount of bleed-out

Table 2 shows the results of evaluation of the minimum growth inhibitory concentration and the bleed-out resistance when the compounds obtained in Production Examples 3 and 4 were used.

[0040]

[Table 2] The antibacterial agents of the present invention of Examples 4 and 5 all showed good antibacterial properties. In addition, compatibility with the silicone resin was high, and bleed-out resistance was also good.

[0041]

The antimicrobial agent for a silicone resin of the present invention has the following advantages: (1) Since it has a high cationic group content and a plurality of repeating structures, it has a high antimicrobial activity even in a small amount. (2) Since the main chain is composed of an organopolysiloxane, the compatibility with silicone resin products is high, and the bleed-out resistance is good. Having the above effects, the antibacterial agent of the present invention is useful as an agent for kneading into silicone resin products such as silicone foam, silicone sealant, silicone rubber, silicone liquid resin, silicone varnish and the like.

Claims (6)

[Claims] 1. An antibacterial agent for a silicone resin, comprising an organopolysiloxane having a portion containing a cationic group in the molecule. 2. The antibacterial agent according to claim 1, wherein the portion containing a cationic group is one in which a plurality of ionic groups are repeatedly located with a nonionic molecular chain interposed therebetween. 3. The nonionic molecular chain is a molecular chain constituted solely by a divalent organic group or a divalent molecular chain in which a plurality of divalent organic groups are bonded, and the divalent organic group is: A divalent hydrocarbon group, an ether group, a carbonyl group, an ester group, an amide group, a divalent organic group containing a urethane group or a urea group, a divalent organic group having a nitrogen or oxygen atom-containing heterocyclic structure and (poly The antibacterial agent according to claim 1 or 2, which is a group selected from the group consisting of oxyalkylene groups. 4. A compound of the general formula (C) [Wherein, R is a monovalent hydrocarbon group, and m and n are from 0 to 1000.
(Where m and n are not simultaneously 0), and X, Y and Z represent a group represented by the following formula (D) or (E) or R (each of which is the same or different) And not all R). ] An antimicrobial agent for a silicone resin comprising an organopolysiloxane having a cationic group in the molecule represented by the formula: Embedded image [Wherein R ¹ , R ⁴ and R ⁷ are a divalent hydrocarbon group, an ether group, a carbonyl group, an ester group, an amide group, a divalent organic group containing a urethane group or a urea group, a nitrogen or oxygen atom divalent molecular chain group and (poly) divalent organic group alone constituted molecular chain or the divalent organic group selected from the group consisting of oxyalkylene groups containing heterocyclic structure is more bound, R ² , R ³ , R ⁵ , R ⁶ , R ⁸ , R ⁹ and R
¹⁰ is 1 which may be substituted with a halogen or a hydroxyl group
Divalent hydrocarbon groups (each of which may be the same or different), W
^- anion, a, b is an integer of 0 to 100 (where, a, b are not 0 at the same time.). [Chemical formula 3] [Wherein R ¹ , R ⁴ and R ⁷ are a divalent hydrocarbon group, an ether group, a carbonyl group, an ester group, an amide group, a divalent organic group containing a urethane group or a urea group, a nitrogen or oxygen atom divalent molecular chain group and (poly) divalent organic group alone constituted molecular chain or the divalent organic group selected from the group consisting of oxyalkylene groups containing heterocyclic structure is more bound, R ² , R ³ , R ⁵ , R ⁶ , R ⁸ , R ⁹ and R
¹⁰ is 1 which may be substituted with a halogen or a hydroxyl group
Divalent hydrocarbon groups (each of which may be the same or different), W
^- anion, a, b is an integer of 0 to 100 (where, a, b are not 0 at the same time.). ] 5. The antibacterial agent according to claim 1, wherein the cationic group is a quaternary ammonium base. 6. A silicone resin to which the antibacterial agent according to claim 1 is added.