JPH05331372A - Room-temperature-curable fluorinated organopolysiloxane composition and its cured article - Google Patents

Abstract

PURPOSE:To obtain a room-temperature-curable compsn. giving a cured article excellent in the resistance to both polar and nonpolar solvents and also in the resistance to chemicals and heat by compounding a fluorinated organosilicon compd., a hydrogenorganopolysiloxane, and a catalyst based on a platinum group metal. CONSTITUTION:The compsn. contains a fluorinated organosilicon compd. of formula I, a hydrogenorganopolysiloxane having at least two Si-H bonds in the molecule, and a catalyst based on a platinum group metal. In formula I, a >=0; Rf is a divalent perfluoroalkylene group or a divalent perfluoropolyether group; R<1> is a divalent hydrocarbon group; and Q is group of formula II or III (wherein R<2> and R<3> are each an unsubstd. monovalent hydrocarbon group having no aliph. unsatd. bond). The compsn., having a low surface energy, is also excellent in releasability and water repellency.

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 and the solvent resistance to polar solvents is poor. 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 4] [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 Q is a general formula (2). :

[Chemical 5] Or general formula (3):

[Chemical 6] (In the formula, each of R ² and R ³ is the same or different unsubstituted or substituted monovalent hydrocarbon group having no aliphatic unsaturated bond.). ] A 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 the above general formula (2) and
It is a divalent cyclosiloxane group represented by (3). A plurality of R ² and R ³ in the general formulas (2) and (3) may be the same or different and each is an unsubstituted or substituted monovalent hydrocarbon group having no aliphatic unsaturated bond. Specifically, a methyl group,
Ethyl group, alkyl group such as propyl group, cycloalkyl group such as cyclohexyl group, phenyl group, aryl group such as tolyl group, 3,3,3-trifluoropropyl group, 6,6,6,
5,5,4,4,3,3-nonafluorohexyl group, chloromethyl group, 3-chloropropyl group, 2-cyanoethyl group, 3-
Examples thereof include groups in which a hydrogen atom of a hydrocarbon group such as a cyanopropyl group is replaced with a halogen atom, a cyano group or the like. As a typical example of Q,

[Chemical 7] And other groups.

Rf in the general formula (1) is a divalent perfluoroalkylene group or a divalent perfluoropolyether group, for example, the general formula (4):

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

[Chemical 9] Is mentioned.

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

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

Further, a in the general formula (1) is an integer of 0 or more, preferably an integer of 3 to 20, and more preferably an integer of 3 to 10.

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) in the presence of an addition reaction catalyst at usually 50 to 150 ° C, preferably 80 to 120 ° C.

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 higher 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
Higher molecular weight polymers are produced as the amounts of the compounds represented by (b) become equal.

As the above-mentioned addition reaction catalyst, there are listed in Table VI of the periodic table.
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 dissolved in an alcohol-based, ketone-based, ether-based, or hydrocarbon-based solvent before use.

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 rubbery polymer. From the viewpoint of ease of handling, for example, a raw rubber-like polymer is preferable in the case of a composition for heat-vulcanized rubber, and 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 formula 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 and Me is as described above) by equilibration with a compound represented by an acid catalyst such as sulfuric acid, or a corresponding halogenated silane or halogenated siloxane. It is prepared by a cohydrolysis reaction with. Also, those having a special functional group such as an epoxy group-containing group are prepared by, for example, a partial addition reaction as described in JP-B-51-33540. Furthermore, 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 should be added to a mixture of tetramethyldisiloxane and hydrochloric acid. Is prepared by.

The hydrogen organopolysiloxane (B) may have either a linear or cyclic structure. Further, it may have either a low molecular weight or a high molecular weight, but in general, a relatively low molecular weight having a molecular weight of 30,000 or less is used from the viewpoint of easy production.

In the component (B), the Si-H group in the component (B) is based on 1 mol of an aliphatic unsaturated group such as vinyl group, allyl group, cycloalkenyl group contained in the composition of the present invention. Preferably 0.5 to 5.0 mol, more preferably 0.5 to 2.0 mol.
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 Si-H group ratio, but it is usually 0.1 parts by weight per 100 parts by weight of the component (A).
˜50 parts by weight, preferably 0.5 to 5.0 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 (wherein Ph is a phenyl group) and the like.

The amount of the platinum group metal catalyst (C) used is not particularly limited, but since the catalyst is expensive, it is
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 prepared from fluorocarbon 11
3, it is preferable to use it after dissolving it in a suitable solvent such as meta-xylene hexafluoride and perfluorobutyl tetrahydrofuran to improve the compatibility with the component (A).

Other Components It is possible to add various other additives 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 having no aliphatic unsaturated double bond.) Resin of organopolysiloxane (Japanese Patent Publication No. 26771/1985).
No. 9476), CH ₂ = CH (R) SiO 2 units for controlling the curing rate of the composition (wherein R is the above R ² and R ^3).
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, etc., 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 such an amount that the ratio of the Si—H group of the component (B) to the aliphatic unsaturated group in the composition is the above-mentioned 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 the mechanical strength and decrease the gas permeability. Examples of the filler include fumed silica, quartz powder, glass fiber, carbon black, metal oxides such as iron oxide, titanium oxide and 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 is
It is also possible to use it after dissolving it in a suitable fluorine-based solvent such as metaxylene hexafluoride or fluorinate at a desired concentration.

Cured Product A 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 the 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 cured product obtained by curing the room temperature-curable fluorine-containing organopolysiloxane composition of the present invention has a high fluorine content, and therefore has excellent resistance to both nonpolar solvents and polar solvents. It exhibits solvent resistance and has excellent 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 a sealant, a molded part, an extruded part, and a coating material for various materials.

[0030]

EXAMPLES Example 1 Formula (5):

[Chemical 18] (In the formula, a is 3 on average, and Rf and Q are respectively represented by the formula:

[Chemical 19] And the formula:

[Chemical 20] Is a group represented by. ) Polymer (viscosity 880
0cSt, average molecular weight 15,000, vinyl group weight 0.013 mol / 100
g) 15 parts by weight of fumed silica having a specific surface area of 200 m ² / g treated with a trimethylsiloxy group was added to 100 parts by weight, mixed and heat-treated, and then mixed on a three-roll mill. 6):

[Chemical 21] 5.3 parts by weight of hydrogen methyl siloxane (0.0043 mol of Si-H group), 0.47 parts by weight of carbon black, and chloroplatinic acid are added as CH ₂ = CHSi (CH ₃ ) ₂ OSi (CH ₃ ) ₂ CH =
0.2 parts by weight of a CH ₂ -modified complex toluene solution (platinum concentration 1.0% by weight) and 2-ethynylisopropanol
0.002 parts by weight was added and mixed. The mixture was degassed under reduced pressure, placed in a rectangular frame having a thickness of 2 mm, deaerated 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 ^* ) 46 Elongation (%) 180 Tensile strength (kgf / cm ² ) 37 (* Note: Measured using A-type spring hardness tester specified in JIS K6301. The same applies hereinafter. )

Example 2 Instead of the hydrogenmethylsiloxane represented by the formula (6) in Example 1, the formula:

[Chemical formula 22] Example 1 except that 6.1 parts by weight of hydrogenmethylsiloxane represented by the formula (Si-H group amount 0.0043 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) 42 Elongation (%) 210 Tensile strength (kgf / cm ² ) 35

Example 3 Instead of the polymer represented by the formula (5) in Example 1, the formula:

[Chemical formula 23] (However, a is 5 on average, and Rf and Q are the following formulas:

[Chemical formula 24] Polymer represented by (viscosity 6300 cSt, average molecular weight 1320
0, vinyl group amount 0.015 mol / 100 g) 100 parts by weight and hydrogen methyl siloxane represented by formula (6) 6.1 parts by weight (Si-H group amount 0.0050 mol) 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) 52 Elongation (%) 150 Tensile strength (kgf / cm ² ) 33

Example 4 Instead of the polymer represented by the formula (5) in Example 1, the formula:

[Chemical 25] (However, a is 10 on average, and Rf and Q are the following formulas:

[Chemical formula 26] Polymer represented by (viscosity 13200 cSt, average molecular weight 1380
0, vinyl group amount 0.014 mol / 100 g) 100 parts by weight and hydrogen methyl siloxane represented by the formula (6) 5.7 parts by weight (Si—H group amount 0.0047 mol) 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) 54 Elongation (%) 160 Tensile strength (kgf / cm ² ) 35

Example 5 The cured product sheets obtained in Examples 1 to 4 were immersed in an acid or alkali aqueous 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 also subjected to the same test. The results are shown in Table 1.

[0035]

[Table 1]

Example 6 The cured sheets obtained in Examples 1 to 4 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. The results are shown in Table 2.

[0037]

[Table 2]

Example 7 The heat resistance test of the cured sheet obtained in Example 1 was conducted. The results are shown in Table 3.

[0039]

[Table 3]

[0040]

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) Noriyuki Koike Inventor Noriyuki Koike, Matsuida-cho, Gunma Prefecture 1-10 Hitomi, Shin-Etsu Chemical Co., Ltd. Silicone Electronic Materials Research Laboratory (72) Takatoshi Matsuda Usui-gun, Gunma Prefecture No. 1 Hitomi, Matsuida-machi, Oita 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 Q is a general formula (2). : [Chemical 2] Or general formula (3): (In the formula, each of R ² and R ³ is the same or different unsubstituted or substituted monovalent hydrocarbon group having no aliphatic unsaturated bond.). ] Fluorine-containing organosilicon compound represented by the following: (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.