JPS6117860B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to room-temperature-curable organopolysiloxane compositions that are easily cured by the action of moisture, and particularly to compositions that have anti-mold properties.

Conventionally, so-called room-temperature-curable organopolysiloxane compositions are known, which are stable and stored as fluid under sealed conditions, but harden at room temperature to become a rubber elastic body under the action of moisture in the atmosphere. This product is widely used as a sealant, coating agent, or adhesive in the construction industry, machinery industry, electrical industry, etc.

However, although cured elastic bodies obtained from conventionally known room-temperature-curable organopolysiloxane compositions have a beautiful appearance at the beginning of construction, they can be used in bathrooms, kitchens, washrooms, etc. where they are exposed to various foreign substances (human dirt, etc.). They have the disadvantage that they are easily contaminated by substances such as food, detergents, food, etc., and when the humidity is high, mold grows, which impairs the appearance, and eventually results in an extremely unsightly condition.

The present invention aims to provide a so-called mildew-resistant, room-temperature-curable organopolysiloxane composition that eliminates the disadvantages of conventional compositions as described above, and is characterized in that (a) both ends of the molecular chain are Diorganopolysiloxane capped with hydroxyl groups 100 parts by weight (b) 1 selected from alkoxy groups, ketoxime groups, acyloxy groups, amino groups, amide groups, and aminoxy groups bonded to silicon atoms in one molecule
Organosilicon compound having at least 3 species or 2 or more types of hydrolyzable groups 0.5 to 30 parts by weight (c) Formula in one molecule (wherein R ¹ , R ² , R ³ and R ⁴ are the same or different monovalent hydrocarbon groups) 0.05 to 15 parts by weight of an organosilicon compound having at least one guanidyl group and (d) curing Accelerator: 0 to 10 parts by weight.

According to this composition, due to the effect of adding component (c),
Do not use the product in environments such as bathrooms, kitchens, or washrooms that have poor ventilation, high humidity (humidity), and are easily contaminated by foreign substances such as human dirt, detergent, or food, and are prone to mold growth. Also, mold growth is suppressed for a long period of time, and the beauty of the construction surface is maintained for a long period of time.

Next, to explain the present invention in more detail, firstly, the diorganopolysiloxane in which both ends of the molecular chain are blocked with hydroxyl groups as the component (a) used as the main component in the present invention is conventionally known as a raw material for silicone rubber. For example, the general formula This is shown in .

Here, R' represents a monovalent hydrocarbon group, including alkyl groups such as methyl, ethyl, and probyl groups, alkeni groups such as vinyl and allyl groups, aryl groups such as phenyl groups, or carbonized groups thereof. Examples include groups in which a hydrogen atom of a hydrogen group is partially substituted with a halogen atom. n represents a positive integer, and the value of n is preferably such that the diorganopolysiloxane exhibits a viscosity of 100 to 1,000,000 centistokes, preferably 3,000 to 50,000 centistokes at 25°C. This is because the above diorganopolysiloxane is 100%
If the viscosity is less than centistokes (25°C), a cured rubber elastic body with excellent physical strength cannot be obtained; on the other hand, if the viscosity is more than 1,000,000 centistokes, this is included. This is because the viscosity of the composition of the present invention becomes too high, resulting in poor workability during use of the composition. Incidentally, it is sufficient that this material has a substantially linear structure, and accordingly, cyclohexane having a three-dimensional structure may be introduced as long as it is in a small amount.

Next, the component (b) used in the present invention is an essential component for the composition of the present invention to cure at room temperature in the presence of moisture, and this component contains silicon in one molecule. Alkoxy group, ketoxime group, acyloxy group, amino group, amide group bonded to an atom,
It is an organosilicon compound having at least three hydrolyzable groups of one or more selected from aminoxy groups.

The organosilicon compound may be either a silane or a siloxane compound, and specific examples include the compounds shown below.

Alkoxysilanes such as methyltrimethoxysilane, vinyltriethoxysilane, 3-chloropropyltrimethoxysilane, 3-aminopropyltriethoxysilane, methyltris(dimethyloxime)silane, methyltris(methylethylketoxime)silane, tetra(methylethylketoxime)silane Ketoxime silanes such as vinyltriacetoxysilane, acyloxysilanes such as methyltriacetoxysilane, amidosilanes such as phenyltris(N-methylacetamido)silane, vinyltris(N-ethylacetamido)silane, vinyltris(N-butylamino)silane, Aminosilanes such as phenyltris(N,N-diethylamino)silane, aminooxysilanes such as methyltris(N,N-dimethylaminooxy)silane, vinyltris(N,N-diethylaminooxy)silane, and 1 of these
A species or a partial hydrolyzate of two or more species.

The amount of component (b) used is in the range of 0.5 to 30 parts by weight per 100 parts by weight of component (a) above; If the amount used is less than 0.5 parts by weight, curing will not proceed well, while if it exceeds 30 parts by weight, the physical properties of the cured rubber elastic body obtained will deteriorate and it will be economically disadvantageous. .

Furthermore, the organosilicon compound as component (c) has at least one guanidyl group represented by the above formula () in the molecule, and this compound is a compound that can be used as a cured rubber elastic material obtained from the composition of the present invention. It imparts antifungal properties (acts like an antibacterial and antifungal agent) to.

In the formula, R ¹ to ^{R 4} represent the same or different monovalent hydrocarbon groups (preferably having 1 to 8 carbon atoms), and include the same groups as those exemplified above for R'. I can do it.

Component (iii) may be either silane or siloxane as long as it has at least one guanidyl group represented by the above formula () in the molecule. Specific examples of such component (iii) include the compounds shown below.

In the formula, Me represents a methyl group, Et represents an ethyl group, Pr represents a propyl group, and Ph represents a phenyl group.

and their partial hydrolysates.

In the present invention, among these, the formula It is preferable to use a compound represented by

This component (c) is usually 0.05 parts by weight per 100 parts by weight of component (a).
It is added in an amount of ~15 parts by weight, preferably from 0.1 to 5 parts by weight, but this is because if component (c) is 0.05 parts by weight or less, a rubber elastic body with good microbial resistance can be obtained. Moreover, if the amount is 15 parts by weight or more, the composition will contain a large amount of guanidyl groups and will easily become colored under heating, which is undesirable.

Furthermore, as the curing accelerator, component (2), used in the present invention, various types conventionally used in this type of composition can be used.
Specifically, the following can be mentioned.

Lead-2-ethyl octoate, dibutyltin diacetate, dibutyltin dilaurate, butyltin tri-2-ethylhexoate, iron-2-ethylhexoate, cobalt-2-ethylhexoate, manganese-2- Organic compounds such as ethylhexoate, zinc-2-ethylhexoate, stannous caprylate, tin naphthenate, tin oleate, tin butyrate, titanium naphthenate, zinc naphthenate, cobalt naphthenate, and zinc stearate. Metal salts of carboxylic acids; organic titanate esters such as tetrabutyl titanate, tetra-2-ethylhexyl titanate, triethanolamine titanate, and tetra(isopropenyloxy) titanate; organic titanium compounds such as organosiloxy titanium and β-carbonyl titanium; Alkoxyaluminum compounds; aminoalkyl group-substituted alkoxysilanes such as 3-aminopropyltriethoxysilane and N-(trimethoxysilylpropyl)ethylenediamine; amine compounds such as hexylamine and dodecylamine phosphate; and their salts; benzyltriethylammonium acetate, etc. 4th of
lower fatty acid salts of alkali metals such as potassium acetate, sodium acetate, and lithium oxalate; dialkylhydroxylamines such as dimethylhydroxylamine and diethylhydroxylamine.

When using the above-mentioned curing accelerator, 1
It is not limited to the type, and two or more types may be used as a mixture. The amount of component (ii) used is 10 parts by weight or less per 100 parts by weight of component (a).

The room-temperature curable organopolysiloxane composition according to the present invention is prepared by mixing the required amounts of each component by conventionally known means, and if necessary, fillers, plasticizers, pigments, etc. Various conventionally known additives such as colorants, heat or cold resistance improvers, flame retardant agents, thixotropic agents, dehydrating agents, adhesion improvers and the like may be blended. In addition, in order to further improve microbial resistance, conventionally known antibacterial and antifungal agents can be added.
(4-thiazolyl)-benzimidazole, N-dimethyl-N'-phenyl-N'-(fluorodichloromethylthio)-sulfamide, 2,3,5,6-
Examples include tetrachloro-4-(methylsulfonyl)pyridine, 3,5-dimethyl-4-chlorophenol, and zinc-2-pyridinethiol-1-oxide.

Next, Examples of the present invention will be given, and all parts in each example indicate parts by weight.

Example 1 A mixture of the formula Cyclic siloxanes of the formula 2.0 parts and 0.5 parts of the cyclic siloxanes shown are mixed, and 3-tris(trimethylsiloxy)silylpropyltetramethylguanidine is added. 0.5 parts were mixed.

This was formed into a sheet with a thickness of 2 mm, cured at room temperature for 7 days, and then cut into a disk shape with a diameter of 3 cm to prepare a test piece.

Then, according to JIS Z 2911, potato dextrose agar was filled in a glass jar with a diameter of 9 cm, and a test piece was placed in the center. Furthermore, a suspension of mold spores of Aspergillus niger, Penicillium citorium, Rhizopus nigricans, Cladosporium helibarum, and Chaetomium globosum was uniformly sprayed, and the jar was covered with a lid.

When the shears were left in a constant temperature and humidity chamber at 28°C and relative humidity of 98% for 28 days, and the specimens were examined, no mold had developed and the original appearance was maintained.

Comparative Example 1 A composition was prepared in the same manner as in Example 1 except that 3-tris(trimethylsiloxy)silylpropyltetramethylguanidine was not used at all, and a mold resistance test was conducted on this composition in accordance with JIS Z 2911. When examining the test piece, it was found that approximately 1/3 of the total area
Black and colored mold was growing in the area.

Example 2 100 parts of dimethylpolysiloxane whose viscosity at 25°C is 20,000 centistokes and whose molecular chain ends are blocked with hydroxyl groups, whose viscosity at 25°C is 100 centistokes
Dimethylpolysiloxane that is centistokes and has both ends of the molecular chain blocked with trimethylsilyl groups.
15 parts of trimethylsilyl group surface-treated fumed silica with a specific surface area of 200 m ² /g, 0.2 parts of dibutyltin dioctoate and 8 parts of methyltris(methylethylketoxime)silane, and further 3-(trimethoxysilyl)propyltetramethyl. 0.8 part of guanidine was mixed.

A cured test piece was prepared in the same manner as in Example 1, a mold resistance test was conducted, and when the test piece was examined, no mold had grown and the initial beauty was maintained.

In addition, after preparing the above composition, it was immediately filled into an aluminum tube and sealed, and when this was kept in a thermostat at 50°C for one month, the composition maintained its initial beauty and fluidity. .

Comparative Example 2 A composition was prepared in the same manner as in Example 2 except that 3-(trimethoxysilyl)propyltetramethylguanidine was not used at all, and a mold resistance test was conducted and the test piece was examined. Black and colored mold was growing on about 1/3 of the area.

Example 3 80 parts of precipitated calcium carbonate and 0.5 parts of 2-(4-thiazolyl)benzimidazole were added to 100 parts of dimethylpolysiloxane, which had a viscosity of 20,000 centistokes at 25°C and was capped with hydroxyl groups at both ends of the molecular chain. of the mixture was added, and the mixture was uniformly kneaded using three rolls to obtain a non-flowable base mixture. Next, add 100 parts of the mixture obtained above to methyltris (N
- 3.0 parts of cyclohexylamino)silane, 1.5 parts of dimethylbis(N-cyclohexylamino)silane
part and formula 0.3 part of a guanidyl group-containing disiloxane represented by was mixed.

This was molded into a 2 mm thick sheet, cured at room temperature for 7 days, and cut into disks with a diameter of 3 cm to obtain three test pieces. One of the three test pieces was immersed in a constant temperature water bath at 50℃ for 7 days (7 days of hot water deterioration), and the other was immersed in a constant temperature water bath of 50℃ for 30 days (hot water deterioration occurred in 7 days).
30 days). The remaining one was used as is without deterioration (initial stage). The three types of test pieces obtained above were individually subjected to a mold resistance test in the same manner as in Example 1, and when the test pieces were examined, it was found that no mold had grown on any of the three types, and the initial beauty was maintained. .

Comparative Example 3 A specimen having the same composition as Example 3 except that no guanidyl group-containing disiloxane was used was treated in almost the same manner to prepare a test piece. A 30-day mold resistance test was conducted.

The initial test piece had no mold and maintained its initial appearance, but the test piece after 7 days of hot water aging had mold growing on about 1/10 of the total area, and after 30 days of hot water aging. Mold was growing on about 1/3 of the total area of the test piece.

Claims (1)

[Scope of Claims] 1 (a) 100 parts by weight of diorganopolysiloxane whose molecular chain ends are capped with hydroxyl groups (b) An alkoxy group, a ketoxime group, an acyloxy group, an amino group bonded to a silicon atom in one molecule 1 selected from group, amide group, aminoxy group
Organosilicon compound having at least 3 species or 2 or more types of hydrolyzable groups 0.5 to 30 parts by weight (c) Formula 1 in one molecule (wherein R ¹ , R ² , R ³ and R ⁴ are the same or different monovalent hydrocarbon groups) 0.05 to 15 parts by weight of an organosilicon compound having at least one guanidyl group and (d) curing An antifungal room temperature curable organopolysiloxane composition comprising 0 to 10 parts by weight of an accelerator.