JPH061920A - Room temperature-curable fluorine-containing organopolysiloxane composition and its cured material - Google Patents

Abstract

PURPOSE:To obtain a room temperature-curable fluorine-containing organopolysiloxane composition providing a cured material having solvent resistance, chemical resistance and heat resistance, comprising a fluorine-containing organosilicon compound, a hydrogenorganopolysiloxane and a platinum group metal-based catalyst. CONSTITUTION:A room temperature-curable fluorine-containing organopolysiloxane composition comprises (A) a fluorinecontaining organosilicon compound of formula I [(a) is >=0 integer; Rf is bifunctional perfluoroalkyl or bifunctional perfluoropolyether group; R<1> is bifunctional hydrocarbon group; R<2> is aliphatic unsaturated group- containing monofunctional hydrocarbon group; Q is siloxane group of formula II (R<3> and R<4> are nonsubstituted or substituted mono-functional hydrocarbon group)], (B) a hydrogenorganopolysiloxane containing two or more SiH groups in one molecule, preferably a compound containing a fluorine-containing group and (C) a platinum group metal-based catalyst (e.g. platinum compound or rhodium compound) and is obtained by blending 100 pts.wt. component A with 0.1-50 pts.wt. component B and 1-1,000ppm based on total amount of the components A and B preferably by predissolving the component C and blending.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a room-temperature-curable fluorine-containing organopolysiloxane composition which is easily cured by leaving it at room temperature or heating, and solvent resistance and resistance obtained by curing the composition. The present invention relates to a cured product having excellent chemical resistance and heat resistance.

[0002]

2. Description of the Related Art Silicone rubber has excellent properties such as electric insulation, heat resistance, cold resistance, and weather resistance, and is used in various fields. However, silicone rubber has the drawback of being poor in solvent resistance. For example, when it is brought into contact with a solvent or immersed in a solvent, it swells, its shape is significantly deformed, and the rubber strength is also lowered. There's a problem. In order to improve the solvent resistance of such silicone rubber, fluorosilicone rubber having a fluoroalkyl group such as 3,3,3-trifluoropropyl group has been developed.

[0003]

However, the above-mentioned fluorosilicone rubber exhibits excellent solvent resistance to nonpolar solvents such as benzene, but extremely swells to polar solvents such as ketones and esters. It is easy to do so and has poor solvent resistance to polar solvents. Therefore, an object of the present invention is to provide a fluorinated silicone rubber composition capable of obtaining a fluorinated silicone rubber exhibiting excellent solvent resistance to both nonpolar solvents and polar solvents, and a cured product thereof. Especially.

[0004]

The present invention provides (A) a general formula
(1):

[Chemical 3] [In the formula, a is an integer of 0 or more, Rf is a divalent perfluoroalkylene group or a divalent perfluoropolyether group, R ¹ is a divalent hydrocarbon group, and R ² is an aliphatic unsaturated group. Is a monovalent hydrocarbon group having a group, and Q is a general formula (2):

[Chemical 4] (In the formula, R ³ and R ⁴ are the same or different and each is an unsubstituted or substituted monovalent hydrocarbon group.) A siloxane group. ] Fluorine-containing organosilicon compound represented by,

(B) Hydrogen organopolysiloxane containing at least two Si--H groups in one molecule, and

(C) A room-temperature-curable fluorine-containing organopolysiloxane composition containing a platinum group metal-based catalyst is provided.

The present invention also provides a cured product obtained by curing the above room temperature-curable fluorine-containing organopolysiloxane composition. Hereinafter, the composition and the cured product of the present invention will be described in detail.

(A) Fluorine-Containing Organosilicon Compound The fluorine-containing organosilicon compound which is the component (A) of the composition of the present invention is a compound represented by the above general formula (1).

Q in the general formula (1) is a divalent siloxane group represented by the general formula (2). A plurality of R ³ and R ⁴ in the general formula (2), which may be the same or different, are unsubstituted or substituted monovalent hydrocarbon groups. Specifically, a methyl group,
Alkyl groups such as ethyl group and propyl group, cycloalkyl groups such as cyclohexyl group, aryl groups such as phenyl group and tolyl group, alkenyl groups such as vinyl group and allyl group, 3,
3,3-trifluoropropyl group, 6,6,6,5,5,4,4,3,3-
Examples include groups in which a hydrogen atom of a hydrocarbon group such as a nonafluorohexyl group, a chloromethyl group, a 3-chloropropyl group, a 2-cyanoethyl group, and a 3-cyanopropyl group is substituted with a halogen atom, a cyano group, or the like. As a typical example of Q,

[Chemical 5] (In the formula, Ph is a phenyl group and Vi is a vinyl group.) And the like.

Rf in the general formula (1) is a divalent perfluoroalkylene group or a divalent perfluoropolyether group, for example, the general formula (3):

[Chemical 6] (Wherein, m is an integer of 0, n is an integer of 2 to 50. Further, the plurality of X is a group represented by well-fluorine atom or -CF ₃ be the same or different. ) Group represented by
General formula (4):

[Chemical 7] (In the formula, k is an integer of 1 to 100.),
And the general formula (5):

[Chemical 8] (In the formula, e and i may be the same or different and are 0 or 1, f and h may be the same or different, and are an integer of 0 to 30, and g is an integer of 0 to 8. The above e,
f, g, h and i are integers that satisfy (e + f + g + h + i) ≧ 1. Further, a plurality of Y may be the same or different and each is a fluorine atom or a group represented by —CF ₃ . And a group represented by). As a typical example,

[Chemical 9] Is mentioned.

R ¹ in the general formula (1) is a divalent hydrocarbon group, preferably having 1 to 8 carbon atoms, more preferably 1 to 6 carbon atoms. In particular,

[Chemical 10] Examples thereof include alkylene groups and arylene groups.

R ² in the general formula (1) is a monovalent hydrocarbon group having an aliphatic unsaturated group and has 2 to 10 carbon atoms.
Those having 2 to 6 are more preferable. Specific examples thereof include an alkenyl group such as a vinyl group and an allyl group, a cycloalkenyl group such as a cyclohexenyl group, and an aryl group such as a styryl group.

Further, a in the general formula (1) is an integer of 0 or more, preferably 0 to 20.

The (A) fluorine-containing organosilicon compound of the present invention has, for example, the formula (a):

[Chemical 11] (In the formula, Rf is as described above.) And a compound having an allyl group at both terminals, and, for example, formula (b): HQH (b) (wherein, Q is the above-mentioned The compound represented by the formula (1) is reacted with the compound represented by the formula (1) at a temperature of usually 50 to 150 ° C, preferably 80 to 120 ° C in the presence of an addition reaction catalyst.

In the above reaction, the amount (mol) of the compound represented by the formula (a) is usually larger than the amount (mol) of the compound represented by the formula (b). The larger the amount of the compound represented by the formula (a) used is, the more the polymer having a relatively low molecular weight is produced. In addition, the amount of the compound represented by the formula (a) and the formula
As the amount of the compound represented by (b) becomes equal, a high molecular weight polymer is produced.

Examples of the addition reaction catalyst include VI
Examples of the group II element or a compound containing the element include chloroplatinic acid, alcohol-modified chloroplatinic acid (see US Pat. No. 3220972), and a complex of chloroplatinic acid and an olefin (US Pat. No. 3159601). , No. 3159662, No. 37754
No. 52), platinum black, palladium, etc. supported on a carrier such as alumina silica, carbon, rhodium-olefin complex, chlorotris (triphenylphosphine) rhodium (Wilkinson catalyst), and the like.
These addition reaction catalysts are preferably used by dissolving them in alcohol-based, ketone-based, ether-based or hydrocarbon-based solvents.

In the present invention, the above-mentioned component (A) comprises several tens.
It is possible to use from low viscosity polymer of cSt (25 ° C) to high viscosity solid raw rubber-like polymer. Considering the ease of handling, for example, in the case of a composition for heat-vulcanized rubber, a raw rubber-like polymer is preferable, and in the case of a composition for liquid rubber, 100 to 100,000 cSt (25 C.) is preferred. If the viscosity of the component (A) is too low, the elongation of the obtained elastomer will be small and balanced physical properties cannot be obtained.

(B) Hydrogen Organopolysiloxa
Emissions Further, hydrogen organopolysiloxane containing two or more Si-H groups on one molecule as the component (B) of the compositions of the present invention act as a crosslinking agent. Specifically, the following compounds are exemplified.

[Chemical 12]

[Chemical 13]

[Chemical 14] (In the formula, s is an integer of 0 to 50, t is an integer of 1 to 10, u is an integer of 1 to 50, Me is a methyl group,
Ph is a phenyl group. )

Preferred among the above-mentioned components (B) are compounds having a fluorine-containing group. When a compound having a fluorine-containing group is used as the component (B), the compatibility with the component (A) is good, so that a more uniform cured product can be obtained.

The hydrogen organopolysiloxane (B) has, for example, the formula:

[Chemical 15] And a compound represented by the formula:

[Chemical 16] And a compound represented by the formula:

[Chemical 17] (Wherein j is an integer of 3 to 8) prepared by equilibration with a compound represented by an acid catalyst such as sulfuric acid, or by cohydrolysis reaction with a corresponding halogenated silane or halogenated siloxane. To be done. In addition, those having a special functional group such as an epoxy group-containing group are disclosed in, for example, Japanese Patent Publication No. 51-3354.
It is prepared by a partial addition reaction as described in 0. Further, for those having a fluorine-containing group such as a fluoroalkylene group, for example, as described in Japanese Patent Application No. 3-24199, a corresponding chlorosilane is added to a mixture of tetramethyldisiloxane and hydrochloric acid. Is prepared by.

The hydrogen organopolysiloxane (B) may have either a linear or cyclic structure. Although it may have either a low molecular weight or a high molecular weight, a relatively low molecular weight compound having a molecular weight of 30,000 or less is generally used from the viewpoint of ease of production.

In the component (B), the Si-H group in the component (B) is based on 1 mol of the aliphatic unsaturated group such as vinyl group, allyl group and cycloalkenyl group contained in the composition of the present invention. , Preferably 0.5 to 5.0 moles, more preferably 1.2 to 3.0 moles.
Use a molar amount. Si- for aliphatic unsaturated groups
If the H group content is too low, the degree of crosslinking will be insufficient, and if it is too high, foaming, heat resistance, compression set characteristics, etc. will be deteriorated. The amount of the component (B) used in the composition of the present invention may be an amount that satisfies the above-mentioned ratio of Si-H groups, but it is usually 0.1 per 100 parts by weight of the component (A).
-50 parts by weight, preferably 0.5-10 parts by weight.

(C) Platinum Group Metal Catalyst The component (C) of the composition of the present invention is a platinum group metal catalyst,
It acts as a catalyst for the addition reaction (hydrosilylation) between component (A) and component (B). Examples of platinum group metal-based catalysts include platinum compounds, rhodium compounds, ruthenium compounds,
Platinum group-based metal compounds such as iridium compounds and palladium compounds are mentioned, but platinum compounds that are relatively easily available are usually used. Examples of the platinum compound include chloroplatinic acid, a complex of chloroplatinic acid with an olefin such as ethylene, a complex of chloroplatinic acid with an alcohol or vinylsiloxane, a solid catalyst such as platinum / silica, platinum / alumina, platinum / carbon and the like. Is mentioned. Examples of catalysts other than platinum compounds include RhCl (PPh ₃ ) ₃ , RhCl (CO) (PPh ₃ ) ₂ and RhC.
_{l (C 2 H 4) 2} , Ru 3 (CO) 12, IrCl (CO) (PPh 3) 2, Pd
(PPh ₃ ) ₄ (in the formula, Ph is a phenyl group) and the like.

The amount of the (C) platinum group metal-based catalyst used is not particularly limited, but since the catalyst is expensive, it can be used as the component (A).
It is usually about 1 to 1000 ppm, preferably about 10 to 500 ppm, based on the total amount of the component (B). Further, in order to obtain a more uniform cured product, the component (C) is preliminarily made of fluorocarbon 11
3, it is preferable to use it after dissolving it in a suitable solvent such as metaxylene hexafluoride and perfluorobutyl tetrahydrofuran to improve the compatibility with the component (A).

Other Ingredients Various other additives may be added to the composition of the present invention, if desired. To be specific, SiO ₂ units for strength to reinforce the cured product obtained by curing the composition of the present _{invention, CH 2 = CH (R '} ) 2 SiO 0.5 units, R' ₃ SiO _0.5 units ( In the formula, R'is a monovalent hydrocarbon group containing no aliphatic unsaturated double bond), which is a resin of an organopolysiloxane (Japanese Examined Patent Publication Nos. 38-26771 and 45-45).
-9476), CH ₂ = CH (R) SiO 2 units for controlling the cure rate of the composition, where R is R ³ and R ⁴ described above.
It is the same group as. ) Containing polysiloxane (Japanese Patent Publication No. 48)
-10947), acetylene compound (US Patent No.
No. 3445420 and Japanese Patent Publication No. 54-3774), heavy metal ionic compounds (see US Pat. No. 3,532,649), and the like. Further, in order to improve thermal shock resistance, flexibility and the like, an appropriate amount of organopolysiloxane having no functional group may be added.

Even when these additives are added,
The component (B) is preferably used in an amount such that the ratio of the Si—H group of the component (B) to the aliphatic unsaturated group in the composition is the above ratio.

Further, the composition of the present invention has reduced heat shrinkage during curing, reduced thermal expansion coefficient of the elastic body obtained by curing, thermal stability, weather resistance, chemical resistance, flame retardancy and A filler may be added to improve mechanical strength and decrease gas permeability. Examples of the filler include fumed silica, quartz powder, glass fiber, carbon black, iron oxide, titanium oxide, metal oxides such as cerium oxide, and metal carbonates such as calcium carbonate and magnesium carbonate. Also, if necessary, it is possible to add appropriate pigments, dyes and antioxidants.

The composition of the present invention may be used depending on its use and purpose.
It is also possible to dissolve it in a suitable fluorine-based solvent, for example, metaxylene hexafluoride, fluorinate, etc., at a desired concentration for use.

Cured Product The composition of the present invention containing the above-mentioned components (A), (B), (C) and various additives optionally added is left at room temperature or heated to The cured product of the present invention is obtained. The curing temperature of the composition of the present invention varies depending on the type of functional group of the component (A), the types of the components (B) and (C), and the amount used, and curing at room temperature is also possible, but usually 100 ~ 150 ℃
Thus, it is possible to cure in a short time of several minutes to several hours.

Uses The room-temperature-curable fluorine-containing organopolysiloxane composition of the present invention and the cured product obtained by curing the composition have a high fluorine content, and therefore are suitable for both nonpolar solvents and polar solvents. Also has excellent solvent resistance, chemical resistance and heat resistance. Further, since it has a low surface energy, it has excellent releasability and water repellency and can be used for various purposes. For example, it is useful as an oil seal, an O-ring, a sealant, a molded part, an extruded part, a coating material for various materials, a release agent, and the like.

[0031]

EXAMPLES Example 1 Formula (6):

[Chemical 18] (In the formula, a is 3 on average, and Rf is the formula:

[Chemical 19] Q is a group represented by the formula:

[Chemical 20] Is a group represented by. ) Polymer (viscosity 960
0cSt, (25 ℃), average molecular weight 21,000, vinyl group weight 0.009
Mol / 100g) To 100 parts by weight, 15 parts by weight of fumed silica treated with a trimethylsiloxy group and having a specific surface area of 200 m ² / g is added, mixed and heat-treated, and then mixed on a three-roll mill. , Equation (7):

[Chemical 21] (In the formula, Me is a methyl group, and Rf is a formula:

[Chemical formula 22] Is a group represented by. 4.8 parts by weight of hydrogenmethylsiloxane (Si-H group amount of 0.0039 mol), carbon black of 0.5 parts by weight, and chloroplatinic acid in CH ₂ = CHSi (CH
₃ ) ₂ OSi (CH ₃ ) ₂ CH = 0.2 parts by weight of a toluene solution of a complex modified with CH ₂ (platinum concentration 1.0% by weight) and 0.3 parts by weight of _2- ethynylisopropanol were added and mixed.
The mixture was degassed under reduced pressure, placed in a rectangular frame having a thickness of 2 mm, evacuated again, and press-cured at 120 kg / cm ² and 150 ° C. for 20 minutes. The hardness, elongation and tensile strength of the obtained sheet-shaped cured product were measured according to JIS K6301. The results are shown below. Hardness (JIS-A ^* ) 42 Elongation (%) 240 Tensile strength (kgf / cm ² ) 40 (* Note: Measured using an A-type spring hardness tester specified in JIS K6301. The same applies hereinafter. )

Example 2 Instead of the hydrogenmethylsiloxane represented by the formula (7) in Example 1, the formula:

[Chemical formula 23] Example 1 except that 5.4 parts by weight of hydrogenmethylsiloxane represented by the formula (Si-H group amount 0.0038 mol) was used.
A sheet-shaped cured product was obtained in the same manner as in. The hardness, elongation and tensile strength of the obtained cured product were measured in the same manner as in Example 1. The results are shown below. Hardness (JIS-A) 39 Elongation (%) 260 Tensile strength (kgf / cm ² ) 36

Example 3 Instead of the polymer represented by the formula (6) in Example 1, the formula:

[Chemical formula 24] (In the formula, a is 5 on average and Rf is the formula:

[Chemical 25] Q is a group represented by the formula:

[Chemical formula 26] Is a group represented by. ) Polymer (viscosity 540
0cSt, (25 ℃), average molecular weight 11600, vinyl group 0.017
Mol / 100 g) 100 parts by weight was used, and 6.5 parts by weight of hydrogenmethylsiloxane represented by the formula (7) was used (Si—H group amount: 0.0053 mol). A cured product was obtained. The hardness, elongation and tensile strength of the obtained cured product were measured in the same manner as in Example 1. The results are shown below. Hardness (JIS-A) 48 Elongation (%) 170 Tensile strength (kgf / cm ² ) 34

Example 4 Instead of the polymer represented by the formula (6) in Example 1, the formula:

[Chemical 27] (In the formula, a is an average of 10 and Rf is the formula:

[Chemical 28] Q is a group represented by the formula:

[Chemical 29] Is a group represented by. ) Polymer represented by (viscosity 1240
0cSt, (25 ℃), average molecular weight 11600, vinyl group 0.017
Mol / 100 g) 100 parts by weight and hydrogen methyl siloxane represented by the formula (7) 6.5 parts by weight (Si-H group amount 0.0054 mol) was used in the same manner as in Example 1 except that A cured product was obtained. The hardness, elongation and tensile strength of the obtained cured product were measured in the same manner as in Example 1. The results are shown below. Hardness (JIS-A) 54 Elongation (%) 160 Tensile strength (kgf / cm ² ) 35

Example 5 Instead of the polymer represented by the formula (6) in Example 1, the formula:

[Chemical 30] (In the formula, a is 3 on average and Rf is the formula:

[Chemical 31] Q is a group represented by the formula:

[Chemical 32] Is a group represented by. ) Polymer (viscosity 750
0cSt, (25 ℃), average molecular weight 21,000, vinyl group weight 0.009
Mol / 100 g) 100 parts by weight and 5.5 parts by weight of hydrogenmethylsiloxane represented by the formula (7) (Si-H group amount: 0.0045 mol) was used in the same manner as in Example 1 except that a sheet form was obtained. A cured product was obtained. The hardness, elongation and tensile strength of the obtained cured product were measured in the same manner as in Example 1. The results are shown below. Hardness (JIS-A) 48 Elongation (%) 170 Tensile strength (kgf / cm ² ) 34

Example 6 The cured product sheets obtained in Examples 1 to 5 were immersed in an aqueous acid or alkali solution at 25 ° C. for 7 days, and the chemical resistance was evaluated by the volume change rate at that time. As a comparative example, silicone rubber (KE-951 manufactured by Shin-Etsu Chemical Co., Ltd.)
) Was subjected to the same test. The results are shown in Table 1.

[0037]

[Table 1]

Example 7 The cured sheets obtained in Examples 1 to 5 were immersed in a solvent at 25 ° C. for 7 days, and the solvent resistance was evaluated by the volume change rate at that time. As a comparative example, the same test was performed on fluororubber (manufactured by DuPont, Viton E-60C). The results are shown in Table 2.

[0039]

[Table 2]

Example 8 The cured product sheet obtained in Example 1 was heated at 200 ° C. for 12 hours.
A 0 hour heat resistance test was performed. The results are shown in Table 3.

[0041]

[Table 3]

[0042]

The cured product obtained by curing the room-temperature-curable fluorine-containing organopolysiloxane composition of the present invention has a high fluorine content and is therefore superior to both nonpolar solvents and polar solvents. It exhibits solvent resistance, and has excellent chemical resistance and heat resistance. Moreover, since the surface energy is low, it is also excellent in releasability and water repellency.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Noriyuki Koike 1 Hitomi, Osamu, Matsuida-cho, Usui-gun, Gunma Prefecture Shin-Etsu Chemical Co., Ltd. Silicone Electronic Materials Research Laboratory (72) Takatoshi Matsuda Usui-gun, Gunma Prefecture No. 1 Hitomi, Oita, Matsuida-cho 10 Shin-Etsu Chemical Co., Ltd. Silicone Electronic Materials Research Laboratory

Claims (2)

[Claims] 1. (A) General formula (1): [In the formula, a is an integer of 0 or more, Rf is a divalent perfluoroalkylene group or a divalent perfluoropolyether group, R ¹ is a divalent hydrocarbon group, and R ² is an aliphatic unsaturated group. Is a monovalent hydrocarbon group having a group, and Q is represented by the general formula (2): (In the formula, R ³ and R ⁴ are the same or different and each is an unsubstituted or substituted monovalent hydrocarbon group.) A siloxane group. ] Fluorine-containing organosilicon compound represented by: (B) Hydrogen organopolysiloxane containing at least two Si-H groups in one molecule, and (C) Room temperature curability containing a platinum group metal-based catalyst Fluorine-containing organopolysiloxane composition. 2. A cured product obtained by curing the room temperature-curable fluorine-containing organopolysiloxane composition according to claim 1.