JP2625313B2 - Room temperature curable silicone rubber composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a curable silicone rubber composition, and more particularly to a room temperature curable silicone rubber composition suitable for dental impression materials.

[0002]

2. Description of the Related Art Addition-curable curable silicone compositions are widely used as impression materials. This curable silicone
The curable composition has excellent curability, has very small shrinkage upon curing, and does not generate by-products. Further, the cured product has excellent dimensional stability, tasteless and odorless, and has excellent characteristics such as easy demolding.

[0003] However, since the conventional curable silicone composition is hydrophobic, if the surface from which the impression is taken is wet, the surface is not well adapted to the surface and it is difficult to obtain an accurate impression. there were. In other words, when using as a dental impression material and taking a wet intraoral mold, it is difficult to obtain a precise impression in detail, and a model is prepared by casting gypsum mud on the obtained impression. Sometimes there was a problem with the wetting of the gypsum mud impression, making it difficult to obtain an accurate model.

Therefore, as a method of improving the wettability to gypsum mud, a method of imparting hydrophilicity by spraying a detergent solution onto the surface of the impression immediately before casting the gypsum mud has been attempted. Curable silicone compositions containing surfactants [Lacy, A., Treleaven, S. & Tendrese
n, M., Cal. Dent. Assn. J., 5, 36-40 (1977), Norli
ng, DK & Reisbick, MH, J. Pros. Dent., 42, 342
-347 (1979)] has also been proposed. Further, JP-A-62-25
Japanese Patent No. 2706 discloses a method of adding a silicone-modified polyether compound as a hydrophilicity-imparting agent to a silicone composition, and Japanese Patent Application Laid-Open No. 63-146805 discloses a method of adding a water-soluble or slightly water-soluble protein. It has been disclosed.

[0005] However, the modified polyether silicone compound has a problem that the silicone oil itself is inherently hydrophobic and thus easily decomposed, and the protein causes odor at the time of an oral impression and rots during long-term storage. Have. In addition, in the method of JP-A-63-130510 in which a nonionic surfactant is added in an amount of 1 to 10% by weight, a small amount is better in that it is difficult to separate. There is a drawback that the wettability at the time of flowing out and gypsum is reduced.

[0006]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems and has a high wettability in both the uncured state and the cured state, and has excellent long-term storage stability at room temperature. It is an object to provide a curable silicone rubber composition.

[0007]

The present invention provides a room-temperature-curable silicone rubber composition comprising the following components (A), (B), (C), (D) and (E). is there. (A) Formula (I): (R ¹ ) _a (R ² ) _b SiO _{[4- (a + b)] / 2} (I) (wherein, R ¹ represents an alkenyl group, and R ² represents an aliphatic group. Represents a substituted or unsubstituted monovalent hydrocarbon group containing no unsaturated bond, a represents 1 or 2, b represents 0, 1 or 2,
And a + b is 1, 2 or 3) in one molecule.

(B) Formula (II): (R ³ ) _c H _d SiO _{[4- (c + d)] / 2} (II) (wherein R ³ is a substituted or unsubstituted monovalent hydrocarbon) C represents O, 1 or 2, d represents 1 or 2, and c + d is 1, 2 or 3), wherein a hydrogen atom bonded to a silicon atom is 1 A polyorganohydrogensiloxane having at least three polyorganosiloxanes in the molecule is represented by R ¹ in the polyorganosiloxane of component (A).
Amount such that the amount of hydrogen atoms bonded to silicon atoms per one group is 0.5 to 5.0

(C) An amount of 1 to 100 ppm of a platinum-based catalyst as a platinum atom with respect to the component (A). (D) One or more components selected from sorbitan fatty acid esters, sucrose fatty acid esters and glycerin fatty acid esters. a) 3 parts by weight or more relative to 100 parts by weight (E) formula (IV): in ^{_{R 5 -0- (CH 2 CH 2}} O) n H (IV) ( wherein, the R ⁵ is an alkyl or alkenyl group Represents n
Represents an integer of from 2 to 15), wherein 3 to 40 parts by weight of an alkyl ether or alkenyl ether of polyoxyethylene represented by the formula (A) is added to 100 parts by weight of component (A).

Hereinafter, the present invention will be described in detail. The polyorganosiloxane of the component (A) used in the present invention has at least two structural units of the formula (I) containing an alkenyl group bonded to a silicon atom in one molecule. As such a polyorganosiloxane, any of a linear or branched or a mixture thereof can be used.

The alkenyl group for R ¹ in the formula (I) includes, for example, vinyl, allyl, 1-butenyl, 1-
Hexenyl and the like can be mentioned, but a vinyl group is the most advantageous in view of easiness of synthesis and thermal stability.

Examples of the monovalent hydrocarbon group for R ² include an alkyl group such as methyl, ethyl, propyl, butyl, hexyl and dodecyl; an aryl group such as phenyl;
-Phenylethyl, aralkyl groups such as β-phenylpropyl, and further, chloromethyl,
Examples include substituted hydrocarbon groups such as 3,3,3-trifluoropropyl. Of these, a methyl group is most preferable because it is easy to synthesize, gives a degree of polymerization necessary for maintaining good physical properties after curing, and gives a low viscosity before curing.

The structural unit represented by the formula (I) may be present at the terminal of the molecular chain of the polyorganosiloxane or in the molecular chain. However, in order to impart excellent mechanical properties to the cured product, It is preferably present at at least one molecular chain terminal.

The viscosity at 25 ° C. of the polyorganosiloxane (A) used in the present invention is 100 to 500,000.
It is preferably 0 cP.

The polyorganohydrogensiloxane of the component (B) used in the present invention has at least three hydrogen atoms bonded to silicon atoms in one molecule in order to form a network by crosslinking. is required. R ³ in the above formula (II) is the same group as R ² in the above formula (I), but is most preferably a methyl group from the viewpoint of easy synthesis.

Component (B) preferably has a viscosity at 25 ° C. of 1 to 10,000 cP in view of ease of synthesis and ease of handling.

As the polyorganohydrogensiloxane (B), any of linear, branched and cyclic structures can be used, and a mixture thereof can also be used.

The amount of the component (B) is preferably 0.5 to 5.0 hydrogen atoms bonded to a silicon atom in the component (B), preferably one alkenyl group in the component (A). 1.0
The amount is such that it is up to 4.0. When the number of hydrogen atoms is less than 0.5, curing of the composition does not proceed sufficiently,
The hardness of the composition after curing is low, and when the number of hydrogen atoms exceeds 5.0, the mechanical properties of the composition after curing deteriorates.

The platinum catalyst of the component (C) used in the present invention is a component for accelerating the addition reaction between the alkenyl group in the component (A) and the hydrosilyl group in the component (B).
Examples of such a platinum-based catalyst include platinum alone, chloroplatinic acid, and a platinum coordination compound such as a platinum-olefin complex or a platinum-alcohol complex.

Component (C) is used in an amount of 1 to 100 ppm, preferably 2 ppm, as platinum atoms with respect to component (A).
~ 50 ppm. If the amount is less than 1 ppm, the object of the present invention cannot be achieved, and if it exceeds 100 ppm, no further improvement in the curing speed can be achieved.

The component (D) and the component (E) used in the present invention are components which can impart stable release properties, storage stability and hydrophilicity when used together. .

The sorbitan fatty acid ester which is one of the components of the component (D) is a sorbitan ester of a fatty acid having 12 to 18 carbon atoms, such as lauric acid, myristic acid, palmitic acid, stearic acid and oleic acid. It is.

The sucrose fatty acid ester is a sucrose ester of a fatty acid selected from fatty acids having 12 to 18 carbon atoms, like the sorbitan fatty acid.

Further, the glycerin fatty acid ester is also a glycerin ester of a fatty acid selected from fatty acids having 12 to 18 carbon atoms.

Of these, in all cases, monofatty acid esters are preferred in terms of compatibility and the like. These can be used alone or in combination of two or more.

The amount of the component (D) is 10
It is at least 3 parts by weight, preferably 5 to 100 parts by weight, based on 0 parts by weight. If the amount is too small, separation of oily substances occurs, which is not preferable.

The alkyl ether or alkenyl ether of the polyoxyethylene of the component (E) used in the present invention is
It is a nonionic surfactant having a polyether as a hydrophilic group as shown by the formula (IV).

By using the component (E) together with the component (D), hydrophilicity can be imparted, and not only good wettability at the time of curing in the oral cavity can be obtained, but also at the time of casting in a gypsum after washing with water. There is an excellent point that the decrease in wettability is small.

R ⁵ in the above formula (IV) is an alkyl group or an alkenyl group and is usually lauryl, cetyl, stearyl or oleyl. N is 2 in terms of compatibility with the siloxane polymer in the silicone rubber composition.
To 15, particularly preferably 4 to 10.

The total amount of component (E) is 3 to 40 parts by weight, preferably 5 to 50 parts by weight, per 100 parts by weight of component (A). If the amount is less than 3 parts by weight, the effect of hydrophilicity due to the loss of the nonionic surfactant is reduced during washing with water in the oral cavity, and if the amount is more than 80 parts by weight, the elasticity of the rubber is lost. Further, it is preferable that the compounding amounts of the component (D) and the component (E) are equal.

The composition of the present invention may optionally contain a reinforcing agent such as an inorganic filler. Examples of such an inorganic filler include fumed silica, precipitated silica, fused silica, quartz fine powder, diatomaceous earth, alumina, aluminum silicate, iron oxide, titanium oxide, zinc oxide, calcium carbonate, and carbon black. And one or more of these can be used. In addition, these inorganic fillers may be provided on the surface thereof with polyorganosiloxanes such as polydimethylsiloxane and octamethylcyclotetrasiloxane as required; hexamethyldisilazane, 1,1,3,3-tetramethyl-1, 3
Those treated with an organosilicon compound such as a silazane such as divinyldisilazane; or an organosilane such as vinyltriethoxysilane.

The mixing ratio of the inorganic filler is not particularly limited, but is preferably 5 to 200 parts by weight, more preferably 10 to 100 parts by weight, per 100 parts by weight of the component (A). is there.

The composition of the present invention can be finally produced by mixing the above five components (A) to (E) so as to be uniform. Although the specific procedure in this case is not particularly limited, usually, the component (D) is blended with the component (A), and after being dispersed as uniformly as possible, other components are added and mixed. In this case, it is preferable to mix the system by heating the system to a temperature equal to or higher than the melting point of the component (D) from the viewpoint of uniformity in the system and reduction of the separation of the component (E). This is because the curing reaction starts immediately when the components (A), (B) and (C) coexist. Therefore, component (A), component (B), and component (C) are preferably allowed to coexist immediately before use in the oral cavity. In this case, an addition reaction retarder such as an acetylene-based compound, an olefin-based compound, an organic nitrogen compound, or an organic phosphorus compound may be added to the composition to suppress the curing reaction. Further, depending on the purpose, other polyorganosiloxanes can be used in combination as long as the effects of the present invention are not impaired.

[0034]

According to the present invention, the room-temperature-curable silicone rubber composition of the present invention can be cured at room temperature in a short time, for example, about several minutes by mixing the components at the time of use. Even during and after curing, the composition of the present invention has hydrophilicity, and has good wettability to a hydrophilic substance or a water-containing substance. Therefore, an accurate impression can be obtained even when used in a humid atmosphere in the oral cavity, and it is particularly suitable as a dental impression material. Further, it can be widely used for molding materials requiring hydrophilicity or other uses.

[0035]

The present invention will be described below in more detail with reference to examples and comparative examples. In the following, all “parts” represent “parts by weight”. All physical property values such as viscosity are values at 25 ° C.

Example 1 and Comparative Examples 1-2 Polydimethylsiloxane having a viscosity of 2,000 cP, both ends of which are blocked with vinyl groups, polymethyl hydride having a viscosity of 80 cP
Rosien siloxane (containing 0.3% by weight of SiH group), octanol chloroplatinate complex (containing 0.4% by weight of platinum),
The fumed silica, quartz fine powder and calcium carbonate were blended according to the composition shown in Table 1, and sorbitan monostearate in the form of a pale yellow flake at 25 ° C and a viscosity of 70 cP
A room temperature-curable silicone rubber composition containing polyoxyethylene oleyl ether was prepared.

Further, the compositions of Comparative Example 1 not containing polyoxyethylene oleyl ether and Comparative Example 2 not containing sorbitan monostearate were also prepared.

These paste-like compositions were mixed and stirred, sandwiched between glass plates with 6 mm spacers inserted, and cured for 10 minutes. One drop of distilled water was dropped on the surface of the obtained cured product, and after 30 seconds and 5 minutes, the contact angle between the water droplet and the surface of the cured product was measured using a contact angle meter (manufactured by Kyowa Kagaku).

Further, those prepared in Example 1 and Comparative Examples 1 and 2 without blending the octanol chloroplatinate complex so as not to cure were left standing for 3 months and observed. Table 1 shows the results.

[0040]

[Table 1]

Examples 2 to 4 and Comparative Examples 3 to 5 In the same manner as in Example 1 except that sorbitan monostearate and polyoxyethylene oleyl ether shown in Table 2 were used in the amounts shown in the same table. Thus, the paste compositions of Examples 2 to 4 and Comparative Examples 3 to 5 were prepared and cured in the same manner as in Example 1.

The contact angles of the cured product obtained by immersing it in tap water for 10 minutes and rinsing it with water and the one not washed were measured for 30 seconds, 5 minutes and 9 minutes after the dropwise addition of distilled water.

Further, those prepared in Examples 2 to 4 and Comparative Examples 3 to 5 in which no octanol chloroplatinate complex was added so as not to be cured were allowed to stand for 3 months and observed. Table 2 shows the results.

[0044]

[Table 2]

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification number Agency reference number FI Technical display location C08L 83/05 C08L 83/05

Claims (1)

(57) [Claims] 1. The following components (A), (B), (C),
A room temperature curable silicone rubber composition comprising (D) and (E). (A) Formula (I): (R ¹ ) _a (R ² ) _b SiO _{[4- (a + b)] / 2} (I) (wherein, R ¹ represents an alkenyl group, and R ² represents an aliphatic group. Represents a substituted or unsubstituted monovalent hydrocarbon group containing no unsaturated bond, a represents 1 or 2, b represents 0, 1 or 2,
And a + b is 1, 2 or 3) polyorganosiloxane having at least two structural units per molecule (B) Formula (II): (R ³ ) _c H _d SiO _{[4- (c + d)] / 2} (II) (wherein, R ³ represents a substituted or unsubstituted monovalent hydrocarbon group. c represents O, 1 or 2, d represents 1 or 2, and c + d represents 1, 2, or 3), and having at least three hydrogen atoms bonded to silicon atoms in one molecule, a polyorganohydrogensiloxane represented by R in the polyorganosiloxane of component (A). ¹
An amount such that the amount of hydrogen atoms bonded to silicon atoms becomes 0.5 to 5.0 relative to one group. (C) 1 to 100 ppm of platinum catalyst as platinum atom with respect to component (A) qs (D) sorbitan fatty acid ester, 3 parts by weight or more of one or more selected from sucrose fatty acid esters and glycerin fatty acid ester of the component (a) 100 parts by weight of (E) formula (IV): R ⁵ -0 — (CH ₂ CH ₂ O) _n H (IV) (wherein R ⁵ represents an alkyl group or an alkenyl group;
Represents an integer of from 2 to 15), wherein 3 to 40 parts by weight of an alkyl ether or alkenyl ether of polyoxyethylene represented by