JPH0655898B2 - Curable organopolysiloxane composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a curable organopolysiloxane composition, particularly for impressions before and after curing, which are wet with water due to their hydrophilicity,
Alternatively, the present invention relates to a curable organopolysiloxane composition effectively used for curved surface printing using an aqueous ink.

[Prior Art] Various curable organopolysiloxane compositions are already known, but for impression materials, especially organopolysiloxanes containing alkenyl groups and hydrogen atoms (≡) bonded to silicon atoms (≡ It is widely used that an addition reaction of an organohydrogenpolysiloxane containing SiH bond) in the presence of a platinum catalyst is performed.This type of composition is nontoxic and odorless and does not produce by-products upon curing. It is widely used for crafts and industrial models because it is highly stable and gives a highly accurate impression.

In addition, these curable organopolysiloxane compositions are hydrophobic and are used as dental impression materials to cure even in the oral cavity wet with saliva, and the surface wet with saliva or sweat is also wiped off and dried. Since it can be cured if used, it is also used as a mold for the human body wet with blood and sweat. For this, the use of nonionic surfactants and fluorine-containing surfactants is also being considered. (See JP-A-63-501368 and JP-A-62-252706).

[Problems to be Solved by the Invention] However, although the addition of this surfactant gives some improvement in the hydrophilicity of the curable organopolysiloxane composition, this nonionic surfactant, fluorine-based surfactant Addition of the agent has the drawbacks that the storage stability of the curable organopolysiloxane composition is impaired and a curing delay occurs, and the physical properties of the cured product, especially hardness and tensile strength, are reduced.

[Means for Solving the Problems] The present invention relates to a curable organopolysiloxane composition capable of solving such disadvantages, and 1) contains at least two alkenyl groups in one molecule. Average prime R ¹ _a R ² _b SiO _{(4-ab) / 2} (where R ¹ is an unsubstituted or substituted monovalent hydrocarbon group having 1 to 7 carbon atoms, R ² is an alkenyl group, and a is 1.8 to 2.02, b is a number of 0.0001 to 1.0) 100 parts by weight of organopolysiloxane represented by 2) 0.5) 0.5 to the alkenyl group contained in the first component
Average composition formula R ³ _{c of the} amount of 5.0 times the molar amount of ≡SiH group supplied
H _d SiO _{(4-cd) / 2} (where R ³ is the same group as R ¹ described above, and c is
An organohydrogenpolysiloxane having at least three hydrogen atoms (≡SiH bonds) directly connected to a silicon atom in one molecule, represented by 1.0 to 2.5 and d is a number from 0.02 to 1.0), and 3) a catalytic amount of platinum. Or a platinum compound, 4) at least one in one molecule, an average composition formula R ⁴ _e R ⁵ _f SiO _{(4-ef) / 2} (wherein R ⁴ is the same group as R ¹ described above, R ⁵ is a substituent) Monovalent hydrocarbon group, e is 1.0 to 2.5, and f is a number of 0.01 to 1.0) 0.5 to 50 parts by weight of an anionic or cationic surfactant containing a siloxane group. Is.

That is, the present inventors have conducted various studies on methods for imparting hydrophilicity to the curable organopolysiloxane composition without deteriorating the storage stability and the physical properties of the cured product. The present invention has been completed by finding that this object can be achieved by adding a surfactant having a siloxane group in one molecule to a known addition reaction-type curable organopolysiloxane composition composed of three components.

This will be described in more detail below.

[Operation] As described above, the curable organopolysiloxane composition of the present invention can be added to the known addition reaction type organopolysiloxane.
A surfactant having a siloxane group in the molecule is added.

The organopolysiloxane as the first component constituting the composition of the present invention is assumed to have alkenyl groups bonded to at least two silicon atoms in one molecule. The average composition formula this thing, represented by ^{_{R 1 a R 2 b SiO (}} 4-ab) / 2, R 1
Is an unsubstituted or substituted C 1-7 monovalent hydrocarbon group,
R ² is an alkenyl group, where a is 1.8 to 2.02 and b is 0.0001 to 1.
0, for example the expression R ¹ is a methyl group, an ethyl group, a propyl group,
Alkyl group having 1 to 7 carbon atoms such as butyl group, aryl group such as phenyl group and tolyl group, or part or all of hydrogen atoms bonded to carbon atoms of these groups are halogen atom, cyano group, etc. A chloromethyl group substituted with
The same or different unsubstituted or substituted monovalent hydrocarbon group excluding aliphatic unsaturated groups selected from trifluoropropyl group, cyanoethyl group, etc., R ² is a lower alkenyl group such as vinyl group, allyl group, m is 50 Up to 100,000 and n / m = 0
The value is 0.1, which is supposed to contain at least two alkenyl groups represented by R ² in one molecule.

Next, since the organohydrogenpolysiloxane as the second component constituting the composition of the present invention acts as a cross-linking agent for the above-mentioned organopolysiloxane as the first component, silicon is included in its molecule. The molecule has at least three hydrogen atoms (≡SiH bonds) directly connected to the atom, and the average composition formula is represented by R ³ _c H _d SiO _{(4-cd) / 2} , and R ³ is the same as R ¹ described above. Same group, c is 1.0 to 2.5, d is 0.
It is necessary that the number is from 02 to 1.0, but it is preferable that it has a lower molecular weight than the first component in order to be compatible with the first component.

The blending amount of the second component depends on the reaction between the first component and the second component when the amount of the ≡SiH bond is less than 0.5 mol with respect to the alkenyl group contained in the first component. If the addition reaction becomes insufficient and the amount of the ≡SiH bond becomes 5 times or more the molar amount of the alkenyl group, the product obtained by this reaction becomes brittle, or the excess ≡SiH bond remains, Since the product may change over time,
This means that the ≡SiH bond is 0 with respect to the alkenyl group in the first component.
It is necessary to add it in the range of 5 to 5 times the molar amount.

The platinum or platinum compound as the third component constituting the composition of the present invention is used as a catalyst for the addition reaction of the above-mentioned first component and second component, which is a known substance. Therefore, platinum black or platinum supported on silica, carbon black, etc., chloroplatinic acid, alcoholic solution of chloroplatinic acid, complex salt of chloroplatinic acid with olefin or vinyl siloxane, etc. An example of such a platinum compound is 0.001 to 0.1 in terms of platinum atom based on 100 parts by weight of the total weight of the first component and the second component because the amount added is a catalytic amount.
It may be in the range of parts by weight.

Next, the surfactant as the fourth component constituting the composition of the present invention is an anionic or cationic surfactant containing at least one siloxane group in one molecule. Average composition formula R ⁴ _e R ⁵ _f SiO
_{(4-ef) / 2} , wherein R ⁴ is the same group as R ¹ described above, R ^4
5 is an expression In expressed, Q is a divalent hydrocarbon group unsubstituted or halogen-substituted having 1 to 10 carbon atoms, or hydroxy-substituted, Y is SO ₃ ^- M ⁺
(Where M is an alkali metal) or N ⁺ R
⁶ ₃ X ^- indicated by (here R ⁶ may be the same or different alkyl group unsubstituted or hydroxyl-substituted C1-10, X is fluorine, chlorine, bromine, a halogen atom such as iodine) It is assumed that e is 1.0 to 2.5 and f is 0.01 to 1.0.

In addition, a and b are positive numbers satisfying 1 ≦ a + b ≦ 3, and the number of silicon atoms in one molecule is 50 or less, preferably 2 to 30.

If the amount of the surfactant as the fourth component is less than 0.5 parts by weight with respect to 100 parts by weight of the alkenyl group-containing organopolysiloxane as the first component, it is possible to impart desirable hydrophilicity to the composition. However, if it exceeds 50 parts by weight, the physical properties of the cured product obtained by the reaction of the first and second components will change, so it is necessary to set it in the range of 0.5 to 50 parts by weight, but the preferred range is The amount is 1 to 30 parts by weight.

The curable organopolysiloxane composition of the present invention can be obtained by mixing predetermined amounts of the above-mentioned first to fourth components, but in order to use this composition as an impression material, suitable fluidity, For this purpose thixotropic properties, strength are required, for which purpose reinforcing agents, fumed silica as fluidity modifier, hydrophobic silica, ground quartz, fused quartz, magnesium carbonate, magnesium sulfate, calcium carbonate. , Metal powders, metal oxides are often added, and hydrogen storage alloys, palladium compounds, metal palladium powders, and hydrogen gas absorbents such as those obtained by supporting these on a carrier such as alumina, carbon, or silica are also added. It is also optional, and liquid paraffin or the like can be added as an internal release agent. Further, various organic nitrogen compounds, organic phosphorus compounds, acetylene compounds and the like may be added to the platinum catalyst for the purpose of suppressing the activity of the platinum-based catalyst to obtain a preferable pot life. It is optional to add iron, cobalt purumate, a quinacridone pigment, a phthalocyanine pigment, an anthraquinone dye, an azo dye, or a fragrance.

The curable organopolysiloxane composition of the present invention thus obtained can be cured at room temperature in a short time, such as several minutes, and the above-mentioned fourth component is added to the cured product. Since it gives hydrophilicity and wettability with a water-containing substance or a hydrophilic substance, this is a dental impression material that requires an accurate impression in a moist atmosphere such as saliva, It is said to be particularly useful as an impression agent for shaping the human body wet with sweat, blood, etc., but it can also be widely used for curved surface printing using water-based ink that requires hydrophilicity and other applications besides shaping. Utility is given.

[Examples] Next, examples of the present invention and comparative examples will be given. In the examples, parts indicate parts by weight, and viscosity indicates a measured value at 25 ° C.

Examples 1 to 5 and Comparative Examples 1 and 2 To 100 parts of dimethylpolysiloxane oil having both ends of a molecular chain having a viscosity of 20,000 cS and blocked with dimethylvinylsiloxy groups, octyl alcohol-modified chloroplatinic acid solution (platinum content 1 Wt%) 0.3 parts, 1,3,5,7-tetramethyl-1,3,5,7
-Tetravinylcyclotetrasiloxane 0.04 parts, quartz powder 850 parts with an average particle size of 4 μm and specific surface area 200 m
5 parts of ² / g of hydrophobic silica was added and uniformly mixed with a mixing stirrer to prepare an organosiloxane base material.

Next, 100 parts of this organosiloxane base material was added to 5 kinds of surfactants (AE) represented by the following rational formulas. 5 parts of Compounds I to V were added to these, the viscosity of which was 12 cS, both ends of the molecular chain were blocked with dimethylhydrogen siloxane groups, and 17 mol% of methylhydrogensiloxy units were contained in the molecule. 5 parts of methylhydrogenpolysiloxane were added to make a curable organopolysiloxane composition, which was placed in a mold and allowed to stand at room temperature for 10 minutes. After curing, the physical properties of this cured product were examined. The results shown in Table 1 were obtained.

Compounds I to V before addition of this methylhydrogenpolysiloxane were stored in a dryer at 60 ° C for 5 weeks to examine their storage stability, and then the above-mentioned methylhydrogenpolysiloxane was added. When the pot life when cured by curing was investigated, the results shown in Table 2 were obtained.

However, for comparison, a surfactant was not added to the above-mentioned organosiloxane base material, and this base material was used as compound VI and the above-mentioned methylhydrogenpolysiloxane was added and cured (Comparative Example 1). In addition, the following rational formula is added to the above-mentioned organosiloxane base material. Compound VII with the addition of 5 parts of surfactant
Was prepared, and 5 parts of the above-mentioned methylhydrogen polysiloxane was added thereto to prepare a curable organopolysiloxane composition, which was cured (Comparative Example 2). The physical properties of the cured product were examined. The results shown in Table 1 were obtained. When the storage stability of these compounds VI and VII was examined, the results shown in Table 2 were obtained.

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Claims (1)

[Claims] 1. An average compositional formula R ¹ _a R ² _b SiO _{(4-ab) / 2} , wherein at least two alkenyl groups are contained in one molecule, wherein R ¹ is a non-C 1-7 non-C group. Substituted or substituted monovalent hydrocarbon group, R ² is alkenyl group, a is 1.8 to 2.02, b is 0.0001 to
100 parts by weight of an organopolysiloxane represented by the formula 1.0), 2) an average compositional formula R of 0.5 to 5.0 times the molar amount of ≡SiH groups with respect to the alkenyl groups contained in the first component. ³ _c H _d SiO _{(4-cd) / 2} (where R ³ is the same group as R ¹ described above, c is 1.0 to 2.5, and d is a number of 0.02 to 1.0) A hydrogen atom directly attached to an atom (≡SiH
Organohydrogenpolysiloxane having at least 3 bonds), 3) catalytic amount of platinum or platinum compound, 4) at least one in one molecule, average composition formula R ⁴ _e R ⁵ _f Si
A siloxane group represented by O _{(4-ef) / 2} (wherein R ⁴ is the same group as R ¹ above, R ⁵ is a substituted monovalent hydrocarbon group, e is 1.0 to 2.5, and f is a number of 0.01 to 1.0). An anionic or cationic surfactant containing 0.5 to 50 parts by weight of a curable organopolysiloxane composition.