JPH0570695A - Curable silicone composition - Google Patents

Abstract

PURPOSE:To provide a curable silicone composition capable of providing rubber elastomers, excellent in solvent and chemical resistance and water and oil repellency and having low moisture permeability by curing. CONSTITUTION:A curable silicone composition is obtained by blending (A) an aliphatic unsaturated group-containing fluorocarbonsiloxane expressed by formula I {R<1> and R<2> are (substituted) monofunctional hydrocarbon; R<3> is 1-8C monofunctnonal hydrocarbon; Rf is bifunctional perfluoroalkylene, etc., expressed by formula II [n is 0-8; m and l are 0-5; j and k are 0 or 1; (1+m+n+j+k) is 11-30]; a is 2-300; b is 0-300; c is 0-5000; p is 2-8; X is triorganosilyl expressed by formula III (R<4> is (substituted) monofunctional hydrocarbon having aliphatic unsaturated bond; R<5> and R<6> are 1-8C monofunctional hydrocarbon} with (B) an Si-H group-containing fluorocarbonsiloxane expressed by formula TV (R<7> is 1-8C hydrocarbon; x and y are O-2) in an amount so as to provide 0.5-5mol groups Si-H based on 1mol aliphatic unsaturated groups in the composition and (C) a platinum family metallic catalyst.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION This invention relates to curable silicone compositions.

[0002]

2. Description of the Related Art According to Japanese Patent Publication No. 58-56582, formula (a):

[Chemical 4] A random or alternating siloxane of formula (b):

[Chemical 5] A curing agent comprising a compound represented by

(C) consist essentially of a homogeneous mixture of an effective amount of platinum-containing catalyst, wherein each R and R'in (A) above is methyl, phenyl, or 3.3.3-trifluoropropyl, respectively. And each Rf is a perfluoroalkylene group having 2 to 10 carbon atoms, a perfluorocycloalkylene group, or a perfluoroalkylene group having 2 to 10 carbon atoms containing 1 or 2 or more -COC-bonds, or perfluorocycloalkylene group. Is an alkylene group, p has a value of 0 to 2q, and when p has a value greater than q, the siloxane (a)
Is only an alternating copolymer with no more than 2 adjacent CH ₃ (CF ₃ CH ₂ CH ₂ ) SiO units, q has an average value of at least 5 and more than an average of 2.0 per molecule in (b) Curable compositions are known in which there are silicon-bonded hydrogen atoms, and the amount of (b) is such that there is 0.5 to 3.0 silicon-bonded hydrogen atoms for each silicon-bonded vinyl group in the composition.

[0004]

However, the cured rubber obtained from the above composition has insufficient solvent resistance, water repellency and oil repellency. Then, the subject of this invention is providing the curable silicone composition which can obtain the hardened | cured material excellent in solvent resistance, water repellency, and oil repellency.

[0005]

Means for Solving the Problems The present inventors have found that the above-mentioned problems can be solved by using, as a main polymer, a polymer having a long divalent fluorine-containing group having 11 to 30 carbon atoms. I found it. That is, the present invention, as a means for solving the above problems,

(A) General formula (1):

[Chemical 6] [Wherein R ¹ and R ² are unsubstituted or substituted monovalent hydrocarbon groups, R ³ is a monovalent hydrocarbon group having 1 to 8 carbon atoms, and
Rf is the following general formula: − (CF ₂ CF ₂ OCF ₂ ) _j − [CF (CF ₃ ) OCF ₂ ] _m − (CF ₂ ) _n − − [CF ₂ OCF (CF ₃ )] _l −CF ₂ OCF ₂ CF ₂ ) _k −

(Here, n is an integer of 0 to 8, m and l are integers of 0 to 5, j and k are integers of 0 or 1, provided that l + m + n + j + k is an integer having 11 to 30 carbon atoms. Is a divalent perfluoroalkylene group or a divalent perfluoropolyether group represented by
An integer of 0, b is an integer of 0 to 300, c is an integer of 0 to 5000,
p represents an integer of 2 to 8, and X is a general formula:

[Chemical 7]

(Wherein R ⁴ is an unsubstituted or substituted monovalent hydrocarbon group having an aliphatic unsaturated bond, and R ⁵ and R ⁶ are monovalent hydrocarbon groups having 1 to 8 carbon atoms). An organosilyl group], a fluorocarbon siloxane represented by

(B) General formula (5):

[Chemical 8] (Wherein Rf is as described above, R ⁷ is a monovalent hydrocarbon group having 1 to 8 carbon atoms; x and y are each 0
An Si-H group-containing fluorocarbon siloxane represented by the formula:

(C) Platinum group metal catalyst is contained, and the amount of the component (B) is 0.5 to 5.0 moles of Si-H group per 1 mole of aliphatic unsaturated group in the composition. And an amount of the curable silicone composition. Hereinafter, the composition of the present invention will be described for each component.

(A) Fluorocarbon containing an aliphatic unsaturated group
In the siloxane general formula (1), examples of the substituted or unsubstituted hydrocarbon group represented by R ¹ and R ² include methyl group, ethyl group, propyl group, butyl group, 2-ethylbutyl group and octyl group. Cycloalkyl groups such as alkyl groups, cyclohexyl groups, cyclopentyl groups, phenyl groups, tolyl groups,
Aryl groups such as xylyl group, naphthyl group and diphenyl group, aralkyl groups such as benzyl group and phenylethyl group,
And all or a part of hydrogen atoms of these groups are substituted with a halogen atom, a cyano group or the like, for example, a chloromethyl group, a trifluoropropyl group, a 2-cyanoethyl group, a 3-cyanopropyl group, C ₂ H ₄ CF (CF ₃ )
Examples thereof include groups such as ₂ . Of these, preferred is an unsubstituted or fluorine-substituted alkyl group having 6 or less carbon atoms, and most preferred is -C ₂ H ₄
CF (CF ₃ ) ₂ and a methyl group. The substituted or unsubstituted monovalent hydrocarbon group R ⁴ having an aliphatic unsaturated group in the terminal organosilyl group X includes, for example, a vinyl group, an allyl group and a hexenyl group, and has 1 to 1 carbon atoms. Examples of the monovalent hydrocarbon groups R ³ , R ⁵ and R ^{6 of 8} include an alkyl group such as a methyl group, an ethyl group, a propyl group, a butyl group, a 2-ethylbutyl group and an octyl group, a cyclohexyl group and a cyclopentyl group. Cycloalkyl group, vinyl group, allyl group, alkenyl group such as hexenyl group, phenyl group, tolyl group, aryl group such as xylyl group, aralkyl group such as benzyl group and phenylethyl group, and all hydrogen atoms of these groups Or a substituted hydrocarbon group partially substituted with a halogen atom, a cyano group, etc., such as a chloromethyl group, a trifluoropropyl group, a 2-cyanoethyl group, 3
- can be exemplified cyanopropyl _{group, -C 2 H 4 CF (CF} 3) 2 and the like groups. Among these, preferred is an unsubstituted or fluorine-substituted alkyl group having 6 or less carbon atoms, and most preferred is -C ₂ H ₄ CF (C
F ₃ ) ₂ and a methyl group.

As typical examples of the divalent perfluoroalkylene group or perfluoropolyether group Rf,

[Chemical 9] Is mentioned.

The polymer (A) can be used in the present invention from a low viscosity polymer having a viscosity of several tens of cSt (25 ° C.) to a solid raw rubber-like polymer. From the viewpoint of ease of handling, for example, a raw rubber-like polymer is suitable for heat-vulcanized rubber, and a polymer of about 100 to 100,000 cSt (25 ° C.) is suitable for liquid rubber. If the viscosity is too low, the resulting cured product will have a small elongation as an elastomer, and balanced physical properties cannot be obtained.

The production of the polymer (A) is shown, for example, in the case where b and c are 0 in the general formula (1):

[Chemical 10] (Wherein R ¹ , Rf and a are as described above). The structural units whose numbers are represented by b and c in the general formula (1) are the corresponding diols, that is,

[Chemical 11]

(Wherein R ² , R ³ and p are as described above) can be introduced by subjecting the disilanol of formula (2) to dehydration condensation together.

Specific examples of these diols include:

[Chemical formula 12] (Here, in each formula, m is an integer of 2 to 12) and the like.

When the diol of the formula (3) is thus obtained,
Next, the fluorocarbon siloxane (A) is obtained by silylating the diol and introducing the silyl group of X at the terminal. As the silylating agent used, for example,
formula:

[Chemical 13] (Where R ⁴ , R ⁵ and R ⁶ are as described above,
M is a halogen atom such as chlorine, bromine or iodine, -NCO,

[Chemical 14] , —CH ₂ COOR (wherein R is a C ₁ to C ₁₀ substituted or unsubstituted monovalent hydrocarbon group), formula:

[Chemical 15]

(Wherein R ⁴ , R ⁵ and R ⁶ are as described above) and the like. Among these, preferred are those of the formula:

[Chemical 16] Etc. As R ⁴ , R ⁵ and R ⁶ in the silylating agent, those corresponding to the terminal group X of the target fluorocarbon siloxane (A) may be selected.

A typical example of the terminal group X is a vinyldimethylsiloxane group,

[Chemical 17] (Wherein q is 0 or 1 and Ph is a phenyl group) and the like. Specific examples of the fluorocarbon siloxane as the component (A) include

[Chemical 18] (Where a, b and c are as described above)

The fluorocarbon siloxane (A) has a fluorocarbon siloxane unit whose number is represented by a as an essential structural unit, and the fluorocarbon siloxane unit includes all siloxane units (number: a + b + c +).
Of 2), 50 mol% or more, preferably 80 mol% or more is preferably contained. If the amount of fluorocarbon siloxane units is small, the resulting cured product has low solvent resistance and chemical resistance, resulting in little effect. Further, when the amount of the aliphatic unsaturated group involved in crosslinking is too large, the crosslinking density becomes too high, and the elongation of the obtained cured product as an elastomer decreases, so that 0.3 mol per 100 g of the fluorocarbon siloxane (A). The following is preferable, and 0.1 mol or less is more preferable.

(B) Si—H group-containing fluorocarbon siloxa
In the general formula (5), the number of carbon atoms represented by R ⁷ is 1 to 8
Examples of the hydrocarbon group include those mentioned for R ⁵ and R ⁶ . Therefore, as an example of the Si-H group-containing fluorocarbon siloxane (B),

[Chemical 19] Is mentioned.

The component (B) has a perfluorocarbon group Rf common to the component (A) in the molecule, and therefore exhibits good compatibility with the component (A). Further, the component (B) acts as a cross-linking agent at the time of curing, but since it has such a fluorine-containing group, it contributes to the improvement of solvent resistance, chemical resistance, etc., which are the features of the fluorine material, These characteristics are not deteriorated. In addition, since the Si-H group is at the end, it is highly reactive.

The component (B) may be added in an amount of 0.1 to 50 parts by weight per 100 parts by weight of the main component (A). However, in reality, the vinyl group, the allyl group and the cyclohexyl group contained in the entire composition are included. 0.5 mol of Si-H group per mol of aliphatic unsaturated group such as alkenyl group
~ 5 mol, preferably 1.2-3.0 mol. If the amount is too small, the degree of crosslinking will be insufficient, and if the amount is too large, foaming, heat resistance, compression set characteristics and the like will be deteriorated. In addition, this crosslinking agent, in order to obtain a uniform cured product,
It is best to use a material that is compatible with component (A).

Si—H group-containing fluorocarbon siloxane
(B) can be produced, for example, by the following formula: CH ₂ = CH-Rf-CH = CH
A diethylene compound of ₂ and the following formula:

[Chemical 20]

(Where Z is an integer of 0 to 2) is reacted with a chlorosilane compound in the presence of an addition reaction catalyst such as platinum, and the following formula:

[Chemical 21] Was synthesized in an aqueous solution of hydrochloric acid.
By co-hydrolyzing with 1,3,3-tetramethyldisiloxane, the target compound represented by the general formula (5) can be obtained.

(C) Platinum group metal catalyst A catalyst for promoting the addition reaction (hydrosilylation) of the component (A) and the component (B). Examples include platinum-based, rhodium-based, ruthenium-based, iridium-based and palladium-based catalysts.

In general, since it is a compound of a noble metal and is expensive, a platinum catalyst which is relatively easily available is often used. Examples of platinum-based catalysts include chloroplatinic acid, complexes of chloroplatinic acid with olefins such as ethylene, complexes of alcohols and vinylsiloxanes, solid catalysts in which platinum is supported on a carrier such as silica, alumina or carbon. is there. In order to obtain a more uniform cured product, it is preferable to use a mixture of chloroplatinic acid and its complex dissolved in an appropriate solvent, which is compatible with the component (A).

Examples of catalysts other than platinum-based catalysts include RhCl (P
φ ₃ ) ₃ , RhCl (CO) (Pφ ₃ ) ₂ , RhCl (C ₂ H ₄ ) ₂ , Ru
₃ (CO) ₁₂ , IrCl (CO) (Pφ ₃ ) ₂ , Pd (Pφ ₃ ) ₄ (where φ is phenyl) and the like. The amount of these catalysts used is not particularly limited, but it may be expensive and is generally 1 to 1000 ppm, preferably 10 to 500 ppm.

Other Ingredients In addition, when the composition is put to practical use, various additives may be further added, if necessary. Specifically, S added to reinforce the strength of the elastic body obtained as a cured product
iO ₂ unit, CH ₂ = CH (R ₂ ) SiO _0.5 unit, R ₃ SiO _0.5
A resin-structured organopolysiloxane composed of a unit (wherein R represents a monovalent hydrocarbon group not containing an aliphatic unsaturated double bond) (see Japanese Patent Publication Nos. 38-26771 and 45-9476). CH ₂ = added to control the cure rate of the composition
CHR ⁵ SiO unit (wherein R ⁵ has the same meaning as described above)
Containing polysiloxane (see JP-B-48-10947)
And acetylene compounds (see U.S. Pat. No. 3,454,420 and Japanese Patent Publication No. 54-3774), and ionic compounds of heavy metals (see U.S. Pat. No. 3,532,649).
Further, an appropriate amount of nonfunctional organopolysiloxane may be added for the purpose of improving thermal shock resistance and flexibility.

When these additives are added, the aliphatic unsaturated group 1 directly bonded to the silicon atom in the entire composition is also 1
Si of organohydrogensiloxane (B) per mole
-H group must be present in an amount of 0.5 to 5 mol.

Further, the composition of the present invention has a reduction in heat shrinkage during curing, a decrease in coefficient of thermal expansion of an elastic body obtained by curing, thermal stability, weather resistance, chemical resistance, flame resistance or mechanical properties. A filler may be added for the purpose of improving the mechanical strength or reducing the gas permeability. Examples of the filler include fumed silica, quartz powder, glass fiber, carbon, metal oxides such as iron oxide, titanium oxide and cerium oxide, and metal carbonates such as calcium carbonate and magnesium carbonate. Further, if necessary, it is possible to add an appropriate pigment, dye or antioxidant. In practical use of the composition of the present invention, the composition may be dissolved in a suitable organic solvent such as benzotrichloride, metaxylenehexafluoride or the like at a desired concentration for use.

Applications and Uses The present composition can be cured at room temperature, but can also be cured at 100 to 200 ° C. for a short time of several hours to several minutes. The composition of the present invention provides a rubber elastic body having excellent solvent resistance, water repellency, and oil repellency, and is particularly useful in the fields of liquid rubber materials for gaskets by FIPG machines, sealants, molded parts, extruded parts, coatings, etc. Is.

[0033]

The function of the composition of the present invention is such that the number of carbon atoms of the Rf group in the main chain is
Since it is 11 to 30, it has excellent solvent resistance, water repellency, and oil repellency. Further, in the main chain - (CF _{2) n} - rubber strength is improved since it is crystalline part rubber which is cured when it has a structural unit having a.

[0034]

EXAMPLES Next, the present invention will be specifically described by way of examples. In the following description, the viscosity is a measured value at 25 ° C.

Example 1 Formula (6):

[Chemical formula 22] (However, a is about 25 on average, and Rf is represented by the formula:

[Chemical formula 23] A group represented by or a formula:

[Chemical formula 24] Group represented by

Fluorocarbon siloxane polymer represented by (viscosity 5700 cSt, average molecular weight 25000, vinyl group amount
0.008 mol / 100 g) To 100 parts by weight, 12 parts by weight of fumed silica filler treated with trimethylsiloxy group was added, mixed and heat-treated, and then mixed on a three-roll mill, and further the formula (7):

[Chemical 25] (However, Rf is the formula:

[Chemical formula 26] Is a group represented by)

Si-H group-containing fluorocarbon siloxane represented by: 3.6 parts by weight, carbon black 0.47 parts by weight, and chloroplatinic acid as CH ₂ = CH-Si (CH ₃ ) _2- O-Si (CH ₃ ) ₂
-CH = CH ₂ modified catalyst solution in toluene (Platinum concentration
1.0% by weight), and 2-ethynylisopropanol 0.00
2 parts by weight were added and mixed. This is degassed under reduced pressure, placed in a rectangular frame, and deflated again, 120 kgf / cm ² , 1
Press cured at 50 ° C. for 20 minutes. The test piece was cut from the cured sample, and the physical properties were measured according to JIS K 6301, and the following results were obtained.

Hardness (JIS-A ^* ): 45 Elongation (%): 290 Tensile strength (kgf / cm ² ): 45 (* Note: A type spring hardness tester specified in JIS K 6301 is used. Measured)

Example 2 Instead of the fluorocarbon siloxane polymer of formula (6), the formula:

[Chemical 27] (However, a has an average of about 36, c has an average of about 4, and Rf has the formula:

[Chemical 28] The fluorocarbon siloxane polymer (viscosity 6500 cSt, average molecular weight 3100, vinyl group amount 0.007 mol / 100 g) represented by the formula (7 ) In place of the Si-H group-containing fluorocarbon siloxane of the formula:

[Chemical 29]

(Where Rf is the formula:

[Chemical 30] The composition was prepared in the same manner as in Example 1 except that 5.1 parts by weight of the group represented by (5) was used to prepare a cured sheet. The test piece was cut out and the physical properties were measured according to JIS K 6301, and the following results were obtained. Hardness (JIS-A): 50 Elongation (%): 310 Tensile strength (kgf / cm ² ): 47

Example 3 Instead of the fluorocarbon siloxane of formula (6), the formula:

[Chemical 31] (Where Rf is the formula:

[Chemical 32] A is about 21 on average, and b is about 9 on average).

A cured sheet was prepared in the same manner as in Example 1 except that 100 parts by weight (viscosity of 5,900 cSt and vinyl group amount of 0.008 mol / 100 g) were used. The test piece was cut out and the physical properties were measured according to JIS K 6301. Hardness (JIS-A): 59 Elongation (%): 250 Tensile strength (kgf / cm ² ): 60

The test results of the elastomers of Examples 1 to 3 for chemical resistance, solvent resistance and surface characteristics are shown below.

[0044]

[Table 1]

As a comparative example, the chemical resistance test results of silicone rubber are also shown. From the above results, it is understood that the elastomer of the present invention has excellent chemical resistance.

[0046]

[Table 2]

[0047]

[Table 3]

[0048]

EFFECTS OF THE INVENTION The curable silicone composition of the present invention, when cured, provides a rubber elastic body having excellent solvent resistance, chemical resistance, water repellency, oil repellency, and low moisture permeability. Further, the composition is excellent in processability, and particularly, if the component (A) having a viscosity of 100,000 cSt or less is used, it is useful as a liquid rubber material for a gasket by a FIPG machine.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Noriyuki Koike, Noriyuki Koike 1 Hitomi, Osamu Matsuida-cho, Usui-gun, Gunma Shin-Etsu Chemical Co., Ltd. Silicone Electronic Materials Research Laboratory (72) Takatoshi Matsuda Usui-gun, Gunma Prefecture Matsuida-machi Ojimi Hitomi 1-10 Shin-Etsu Chemical Co., Ltd. Silicone Electronic Materials Research Laboratory (72) Inventor Hirofumi Kinoshita Gunma Prefecture Usui-gun Matsuida-cho Daiji Hitomi 10 Shin-Etsu Chemical Industrial Silicone Electronic Materials Research Institute

Claims (1)

[Claims] 1. (A) General formula (1): [Wherein R ¹ and R ² are unsubstituted or substituted monovalent hydrocarbon groups, R ³ is a monovalent hydrocarbon group having 1 to 8 carbon atoms, and
Rf is the following general formula: − (CF ₂ CF ₂ OCF ₂ ) _j − [CF (CF ₃ ) OCF ₂ ] _m − (CF ₂ ) _n − − [CF ₂ OCF (CF ₃ )] _l −CF ₂ OCF ₂ CF ₂ ) _k − (where n is an integer of 0 to 8, m and l are integers of 0 to 5, j and k are integers of 0 or 1, and 1 + m + n
+ J + k is an integer having 11 to 30 carbon atoms) or a divalent perfluoroalkylene group or a divalent perfluoropolyether group, and a is an integer of 2 to 300,
b is an integer of 0 to 300, c is an integer of 0 to 5000, and p is 2 to 8.
, And X is the general formula: (Here, R ⁴ is an unsubstituted or substituted monovalent hydrocarbon group having an aliphatic unsaturated bond, R ⁵ and R ⁶ are C 1-8 carbon atoms.
A triorganosilyl group represented by
An aliphatic unsaturated group-containing fluorocarbon siloxane represented by: (B) General formula (5): (Wherein Rf is as described above, R ⁷ is a monovalent hydrocarbon group having 1 to 8 carbon atoms; x and y are each 0
Which is an integer of 2 to 3), a fluorocarbon siloxane containing a Si-H group, (C) a platinum group metal-based catalyst, and the amount of the component (B) is an aliphatic unsaturated group in the composition. A curable silicone composition in which the amount of Si-H groups is 0.5 to 5.0 mol per mol.