JPS6352062B2 - - Google Patents

Description

[Detailed description of the invention]

[Technical Field of the Invention] The present invention relates to a polyorganosiloxane composition whose cured state can be immediately determined by a change in color. [Technical background of the invention and its problems] An addition reaction type liquid silicone rubber composition is an addition reaction of a polyorganosiloxane having an alkenyl group and a polyorganohydrodiene siloxane having a hydrogen atom bonded to a silicon atom with a platinum compound or the like. A composition that is cured using a catalyst for
It is already well known (see Japanese Patent Publication No. 43-27853, etc.). Conventionally, in order to examine the cured state of rubber obtained from these liquid silicone rubber compositions, it was necessary to actually touch the silicone rubber composition in the middle of curing and observe it with your finger, or measure the penetration and rubber hardness. I had to make a decision based on what I did. For example, when using liquid silicone for mold making molds or liquid silicone rubber for dental impression materials, workers and dentists use silicone rubber each time they remove the silicone rubber mold from the master mold or the inside of the oral cavity. It was necessary to judge the hardening state of the rubber by touching it with one's fingers, and to continue observing it with one's fingers until it was possible to remove it from the mold. For this reason, valuable time is wasted by the workers in determining the cured state, which often interferes with the original medical treatment activities. Moreover, since the curing completion time cannot be determined sufficiently by touch,
The mold was demolded or the next operation was carried out even though the rubber had not sufficiently cured, which often caused problems such as damage to the rubber and adhesion to the original mold. [Purpose of the Invention] The present invention is capable of detecting the hardening state of rubber by detecting color changes without the need for troublesome operations such as tactile observation or measuring penetration and rubber hardness. The purpose of the present invention is to provide a polyorganosiloxane composition whose cured state can be easily determined. [Structure of the Invention] As a result of intensive research aimed at improving these disadvantageous aspects, the present inventor has developed a silicone rubber composition that is cured by the reaction between a hydrosilyl group and an alkenyl group bonded to a silicon atom. It has been found that by adding an anthraquinone dye as a third component, a polyorganosiloxane composition can be obtained which changes color or disappears as the curing progresses, and whose cured state can be visually determined. That is, the polyorganosiloxane composition of the present invention has (A) the following formula: (In the formula, R ¹ is an alkenyl group, R ² is a substituted or unsubstituted monovalent hydrocarbon group that does not contain an aliphatic unsaturated bond, a is an integer of 1 or 2, and b is 0.
-2, a+b is an integer of 1-3) Polyorganosiloxane having at least two units represented by the following in the molecule: 100 parts by weight (B) The following formula: (In the formula, R ³ represents a substituted or unsubstituted monovalent hydrocarbon group, c is an integer of 0 to 2, d is an integer of 1 or 2, and c+d is an integer of 1 to 3) Polyorganohydrodienesiloxane having at least 3 hydrogen atoms bonded to silicon atoms in the molecule: Hydrogen bonded to silicon atoms for each R ¹ group in polyorganosiloxane (A) number of atoms is 0.5
(C) a catalyst selected from the group consisting of platinum and platinum compounds: 1 to 100 ppm as platinum atoms relative to the polyorganosiloxane (A); and (D) an anthraquinone dye: polyorganosiloxane. It is characterized by comprising 1 to 2000 ppm of siloxane (A). The present invention will be explained in more detail below. Polyorganosiloxane (A) used in the present invention
has at least two alkenyl groups in one molecule directly bonded to a silicon atom. The polyorganosiloxane (A) may be either linear or branched, or a mixture thereof may be used. Examples of R ¹ in the above formula include a vinyl group, an allyl group, a 1-butenyl group, and a 1-hexenyl group, but a vinyl group is most advantageous in terms of ease of synthesis. Organic groups bonded to the silicon atom of R ² and other siloxy units include alkyl groups such as methyl, ethyl, propyl, butyl, hexyl, and dodecyl; aryl groups such as phenyl; β-phenylethyl group, β-
Examples include aralkyl groups such as phenylpropyl, and further examples include substituted hydrocarbon groups such as chloromethyl and 3,3,3-trifluoropropyl. Among these, polyorganosiloxanes are easy to synthesize and have the necessary degree of polymerization to maintain good physical properties after curing.
A methyl group is most preferred because it exhibits low viscosity before curing. In addition, when the composition of the present invention is used for casting, potting, coating, impregnation, etc., it has properties suitable for this purpose, especially appropriate flowability before curing, and excellent physical properties after curing. In order to obtain
It is preferable that it is in the range of . If the viscosity is less than 50 cP, it will be difficult to obtain sufficient elongation and elasticity after curing, and if the viscosity exceeds 200,000 cP, workability in casting, potting, and other operations will be poor. The polyorganohydrodiene siloxane used in the present invention as component (B) must have at least three silicon-bonded hydrogen atoms in one molecule in order to form a network through crosslinking. It is. Examples of the organic group bonded to the silicon atom of R ³ and other siloxy units in the above formula include those similar to R ² in the component (A) above, but from the viewpoint of easy synthesis,
Most preferred is the methyl group. The polyorganohydrodiene siloxane (B) may be linear, branched or cyclic, or a mixture thereof may be used. In terms of imparting good physical properties to the composition itself after curing, component (B) includes the following a to c.
The compounds shown in are preferred. a Branched polyorganohydrodiene siloxane consisting of (CH ₃ ) ₂ HSiO1/2 and SiO ₂ units and having a content of hydrogen atoms bonded to silicon atoms in the range of 0.3 to 1.2% by weight of the molecular weight b The following formula: (where p is an integer of 3 to 100 and q is an integer of 0 to 100), and the content of hydrogen atoms bonded to silicon atoms is in the range of 0.5 to 1.6% by weight of the molecular weight. Organohydrogensiloxane c following formula: (where p is an integer of 1 to 100 and q is an integer of 0 to 100), and the content of hydrogen atoms bonded to silicon atoms is in the range of 0.5 to 1.6% by weight of the molecular weight. Organohydrodiene siloxane The amount of component B used is 1 alkenyl group in component (A).
The amount is such that the number of hydrogen atoms bonded to silicon atoms in component (B) is 0.5 to 4.0, preferably 1.0 to 3.0. If the number of hydrogen atoms is less than 0.5, the curing of the composition will not proceed sufficiently, and the hardness of the composition after curing will be low.
If the amount exceeds 1, the physical properties of the cured composition will deteriorate. The platinum-based catalyst as component (C) used in the present invention is (A)
It is used to promote the addition reaction between the alkenyl group of the component and the hydrosilyl group of the component (B), and contains simple platinum, chloroplatinic acid, platinum-olefin complexes, platinum-alcohol complexes, platinum coordination compounds, etc. Illustrated. The amount of component (C) used is in the range of 1 to 100 ppm in platinum atoms relative to component (A). If the content is less than 1 ppm, the effect of the present invention cannot be achieved, and if it exceeds 100 ppm, no improvement in curing speed can be expected. The anthraquinone dye used in the present invention as the component (D) is most preferably one that is soluble in the polyorganosiloxane as the component (A) or (B). Since it can be used by being dispersed and mixed in a substance, it may be soluble in an organic solvent. Furthermore, the effects of the present invention are not lost even if the dye is simply mixed and dispersed in the polyorganosiloxane composition, so even if it is insoluble in components (A) and (B), it can be used. As an anthraquinone dye, Kayaset Blue 814 (Nippon Kayaku
Co., Ltd. (trade name), Oriental Oil Blue K (Toyo Ink Manufacturing Co., Ltd., trade name), Orient Oil Violet #730 (Orient Chemical Industries Co., Ltd., trade name), Sumiplast Blue CA ( Sumitomo Chemical Co., Ltd.
Examples include product name, product name), etc. The amount of component (D) used is in the range of 1 to 2000 ppm relative to component (A).
At the end of 1 ppm, the effect of the present invention cannot be achieved, and
If it is within 2000 ppm, it is sufficient to observe discoloration or decolorization, and if it is added more than that, the effect of the present invention may not be achieved. The composition of the present invention may additionally contain a filler as needed, and may also contain a solvent or other polyorganic material to the extent that the effects of the present invention are not impaired. Siloxane may also be used in combination.
Such additives typically include fumed silica, precipitated silica, quartz powder, diatomaceous earth,
Examples include glass beads, toluene, hexane, polydimethylsiloxane, etc., but additives that are naturally colored or fillers with strong hiding power, such as titanium oxide and iron oxide, are used in combination. Not suitable for purpose. Note that addition reaction type liquid silicone rubber cures even if it is left at room temperature, but it is also possible to further accelerate curing by heating. In the polyorganosiloxane composition according to the present invention,
Even in such heat curing, the rubber changes color or disappears as it hardens, and the cured state can be visually clarified. [Effect of the invention] In the case of ordinary addition-type liquid silicone rubber,
A rubber-like cured product is obtained by stirring and mixing a component consisting of a polyorganosiloxane having an alkenyl group and a platinum compound, and a component consisting of a polyorganohydrodiene siloxane having a hydrogen atom bonded to a silicon atom at a predetermined ratio. However, in the silicone rubber composition of the present invention,
By coloring at least one of the polysiloxane components by adding an anthraquinone dye, it becomes possible not only to determine the sufficient mixing state of the two components, but also to observe the cured state by the change in color. [Example] The present invention will be explained below with reference to Examples. In addition,
In the examples, all parts indicate parts by weight. Example 1 Component S-1(a) was prepared by adding and stirring an isopropyl alcohol solution of chloroplatinic acid in an amount of 20 ppm as platinum to 100 parts of polydimethylsiloxane having a viscosity of 300 cP at 25° C. and having both ends blocked with dimethylvinyl groups. (CH ₃ ) ₂ Consists of HSiO1/2 units and SiO ₂ units,
100 parts of polymethylhydrodiene siloxane containing 1.02% by weight of hydrogen atoms bonded to silicon atoms and having a viscosity of 21 cP at 25°C was mixed with Kaya Set Blue 814.
(manufactured by Nippon Kayaku Co., Ltd., trade name) was added at 60 ppm and stirred to prepare component S-1(b) colored blue. When 4 parts of S-1(b) was added to 100 parts of S-1(a) and stirred, the mixture uniformly turned blue, and the adequacy of stirring could be clearly determined visually. Furthermore, when this material was left to cure at 25°C and 80°C, the blue color changed to the edge color as the rubber hardened, as shown in Table 1, and curing could be clearly determined from the color change. . Example 2 100 parts of polydimethylsiloxane base oil blocked by dimethylvinyl groups with a viscosity of 3000 cP at 25°C, Crystallite VX-SS (manufactured by Kamomori Co., Ltd.)
Product name) 20 parts, 2 parts of linear polymethylhydrodiene siloxane with both ends blocked with trimethylsilyl groups and silicon-bonded hydrogen content of 0.8% by weight and 20 cP at 25°C, isopropyl chloroplatinic acid Blue composition S-2 was prepared by mixing and uniformly dispersing 30 ppm of an alcohol solution (as platinum based on the base oil) and 100 ppm of a toluene solution of Kayaset Blue 814 (as Kayaset Blue 814 based on the base oil).
When this product was left at 25℃, the second
As shown in the table, the blue color disappeared (decolorized) as the rubber cured, and curing could be clearly determined from the color change. Example 3 100 parts of polydimethylsiloxane base oil with dimethylvinylsilyl group closure at both ends, viscosity 10000 cP at 25°C, fumed silica Aerosil 200
(manufactured by Degutsusa Co., Ltd., trade name) 15 parts, (CH ₃ ) ₂ HSiO1/
2 units and SiO ₂ units, contains 1.02% by weight of hydrogen atoms bonded to silicon atoms, and has a viscosity at 25℃.
21cP polymethylhydrodiene siloxane 1.5
15 ppm of chloroplatinic acid (as platinum to base oil) and Oriental Oil Blue K
(manufactured by Toyo Ink Manufacturing Co., Ltd., trade name) in a toluene solution (oriental oil blue K based on the base oil) of 50 ppm was mixed and uniformly dispersed to prepare blue composition S-3. When this product was left to stand at room temperature, the color of the edges changed as the rubber hardened, and hardening could be determined.

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Claims (1)

[Claims] 1 (A) The following formula: (In the formula, R ¹ is an alkenyl group, R ² is a substituted or unsubstituted monovalent hydrocarbon group that does not contain an aliphatic unsaturated bond, a is an integer of 1 or 2, and b is 0.
-2, a+b is an integer of 1-3) Polyorganosiloxane having at least two units represented by the following in the molecule: 100 parts by weight (B) The following formula: (In the formula, R ³ represents a substituted or unsubstituted monovalent hydrocarbon group, c is an integer of 0 to 2, d is an integer of 1 or 2, and c+d is an integer of 1 to 3) Polyorganohydrodienesiloxane having at least 3 hydrogen atoms bonded to silicon atoms in the molecule: Hydrogen bonded to silicon atoms for each R ¹ group in polyorganosiloxane (A) number of atoms is 0.5
(C) a catalyst selected from the group consisting of platinum and platinum compounds: 1 to 100 ppm as platinum atoms relative to the polyorganosiloxane (A); and (D) an anthraquinone dye: polyorganosiloxane. A polyorganosiloxane composition comprising 1 to 2000 ppm of siloxane (A). 2. The composition according to claim 1, wherein R ¹ in (A) is a vinyl group. 3 The polyorganohydrodiene siloxane (B) has the following formula: R ⁴ (CH ₃ ) ₂ SiO−[(CH ₃ )HSiO]— _P [—(CH ₃ ) ₂ SiO]
_−q Si(CH ₃ ) ₂ R ⁴ [wherein R ⁴ represents a hydrogen atom or a methyl group,
p is 1 to 100 (provided that when both R ⁴ are methyl groups, p is 3 to 100), and q is an integer of 0 to 100. Composition of. 4 The polyorganohydrodiene siloxane (B) consists of (CH ₃ ) ₂ HSiO1/2 units and SiO ₂ units,
The composition according to claim 1, wherein the content of hydrogen atoms bonded to silicon atoms is 0.3 to 1.2% by weight of the molecular weight.