JP2619753B2 - Curable silicone composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

This invention relates to curable silicone compositions.

[0002]

2. Description of the Related Art According to Japanese Patent Publication No. 58-56582, the following equation (a) is used.

Embedded image A random or alternating siloxane of the formula (b):

Embedded image A curing agent comprising a compound represented by

(C) consisting essentially of a homogeneous mixture of an effective amount of a platinum-containing catalyst, wherein each R and R 'in (A) is methyl, phenyl, or 3.3.3-trifluoropropyl, respectively. Wherein each Rf is a perfluoroalkylene group of 2 to 10 carbon atoms, a perfluorocycloalkylene group, or a 2 to 10 carbon atom perfluoroalkylene group or a perfluorocycloalkyl group containing one or more -COC- bonds. An alkylene group, p has a value of 0 to 2q, and when p has a value greater than q, the siloxane (a)
Are only alternating copolymers with no more than two adjacent CH ₃ (CF ₃ CH ₂ CH ₂ ) SiO units, q has an average value of at least 5, and an average of more than 2.0 per molecule of (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. Accordingly, an object of the present invention is to provide a curable silicone composition that can provide a cured product having excellent solvent resistance, water repellency, and oil repellency.

[0005]

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

(A) General formula (1):

Embedded image [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 a 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 1 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. A) a divalent perfluoroalkylene group or a divalent perfluoropolyether group represented by
0 is an integer, b is an integer from 0 to 300, c is an integer from 0 to 5000,
p represents an integer of 2 to 8, and X represents a general formula:

Embedded image

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]

(B) General formula (5):

Embedded image (Where 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 from 2 to 2)

(C) A platinum group metal catalyst is contained, and the amount of the component (B) is 0.5 to 5.0 moles per mole of the aliphatic unsaturated group in the composition. An amount of the curable silicone composition is provided. Hereinafter, the composition of the present invention will be described for each component.

(A) Fluorocarbon containing 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 a methyl group, an ethyl group, a propyl group, a butyl group, a 2-ethylbutyl group and an octyl group. Alkyl group, cyclohexyl group, cycloalkyl group such as cyclopentyl group, phenyl group, tolyl group,
Xylyl group, naphthyl group, aryl group such as diphenyl group, benzyl group, aralkyl group such as phenylethyl group,
And a substituted hydrocarbon group in which all or a part of the hydrogen atoms of these groups are substituted with a halogen atom, a cyano group, and the like, for example, a chloromethyl group, a trifluoropropyl group, a 2-cyanoethyl group, a 3-cyanopropyl group, and- C ₂ H ₄ CF (CF ₃ )
Examples of groups such as ₂ can be given. Preferred are Among these, an unsubstituted or fluorine-substituted alkyl group having a carbon number of 6 or less, and most preferred are -C ₂ H ₄
CF (CF ₃₎ is a ₂ and a methyl group. Examples of the substituted or unsubstituted monovalent hydrocarbon group R ⁴ having an aliphatic unsaturated group in the terminal organosilyl group X include a vinyl group, an allyl group, and a hexenyl group, and have 1 to 1 carbon atoms. Examples of the monovalent hydrocarbon groups R ³ , R ⁵ and R ⁶ include alkyl groups such as methyl group, ethyl group, propyl group, butyl group, 2-ethylbutyl group and octyl group, cyclohexyl group, cyclopentyl group and the like. Alkenyl groups such as cycloalkyl group, vinyl group, allyl group, and hexenyl group; aryl groups such as phenyl group, tolyl group and xylyl group; aralkyl groups 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., for example, a chloromethyl group, a trifluoropropyl group, a 2-cyanoethyl group,
- can be exemplified cyanopropyl _{group, -C 2 H 4 CF (CF} 3) 2 and the like groups. Among these, preferred are an unsubstituted or fluorine-substituted alkyl group having a carbon number of 6 or less, and most preferred are -C ₂ H ₄ CF (C
F ₃ ) ₂ and a methyl group.

Representative examples of the divalent perfluoroalkylene group or perfluoropolyether group Rf include:

Embedded image Is mentioned.

The polymer (A) can be used in the present invention from a low viscosity polymer 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 hot 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 low elongation as an elastomer, and a balanced physical property cannot be obtained.

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

Embedded image (Wherein R ¹ , Rf and a are as described above). The structural units indicated by b and c in the general formula (1) are corresponding diols, that is,

Embedded image

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

Specific examples of these diols include:

Embedded image (Where m is an integer of 2 to 12 in each formula) and the like.

When the diol of the formula (3) is thus obtained,
Next, the diol is silylated, and the silyl group of X is introduced into the terminal to obtain a fluorocarbon siloxane (A). As the silylating agent used, for example,
formula:

Embedded image (Where R ⁴ , R ⁵ and R ⁶ are as defined above,
M is a halogen atom such as chlorine, bromine or iodine, -NCO,

Embedded image , -CH ₂ COOR (wherein, R is a substituted or unsubstituted monovalent hydrocarbon group of C ₁ ~ C _10), wherein:

Embedded image

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

Embedded image And so on. R ⁴ , R ⁵ and R ⁶ in the silylating agent may be selected from those corresponding to the desired terminal group X of the fluorocarbon siloxane (A).

Representative examples of the terminal group X include a vinyldimethylsiloxane group,

Embedded image (Where q is 0 or 1, Ph is a phenyl group) and the like. As specific examples of the fluorocarbon siloxane of the component (A),

Embedded image (Where a, b and c are as described above)

The fluorocarbon siloxane (A) has a fluorocarbon siloxane unit represented by a as an essential structural unit, and the fluorocarbon siloxane unit is composed of all siloxane units (number: a + b + c +
Of 2), the content is preferably at least 50 mol%, preferably at least 80 mol%. If the amount of fluorocarbon siloxane units is small, the cured product obtained has low solvent resistance and chemical resistance, and has little effect. Further, if the amount of the aliphatic unsaturated group involved in the crosslinking is too large, the crosslinking density becomes too high, and the obtained cured product is reduced in elongation as an elastomer.Therefore, 0.3 mol per 100 g of the fluorocarbon siloxane (A) is used. Or less, more preferably 0.1 mol or less.

(B) Fluorocarbon Siloxae Containing Si-H Group
In the general formula (5), 1 to 8 carbon atoms represented by R ⁷
Examples of the hydrocarbon group include those exemplified for R ⁵ and R ⁶ above. Therefore, as an example of the Si-H group-containing fluorocarbon siloxane (B),

Embedded image Is mentioned.

The component (B) has a perfluorocarbon group Rf in common with the component (A) in the molecule, and therefore exhibits good compatibility with the component (A). In addition, the component (B) acts as a cross-linking agent at the time of curing, but since it itself has such a fluorine-containing group, it contributes to the improvement of the solvent resistance and chemical resistance, which are the characteristics of the fluorine material, They do not degrade these properties. In addition, since the Si-H group is at the terminal, the reactivity is high.

The amount of component (B) added is preferably 0.1 to 50 parts by weight per 100 parts by weight of main component (A), but in practice, vinyl group, allyl group, cyclo group, etc. 0.5 mole of Si-H group per mole of aliphatic unsaturated group such as alkenyl group
５5 mol, preferably 1.2-3.0 mol. If the amount is too small, the degree of crosslinking becomes insufficient. If the amount is too large, foaming or heat resistance, compression set characteristics, etc. are deteriorated. In addition, this crosslinking agent, in order to obtain a uniform cured product,
It is better to use one that is compatible with component (A).

Si-H group-containing fluorocarbon siloxane
The production of (B) is carried out, for example, by the following formula: CH ₂ = CH-Rf-CH = CH
_2, a diethylene compound represented by the following formula:

Embedded image

(Where Z is an integer of 0 to 2) with a chlorosilane compound in the presence of an addition reaction catalyst such as platinum.

Embedded image Are synthesized in an aqueous hydrochloric acid solution.
By co-hydrolyzing with 1,3,3-tetramethyldisiloxane, the desired product represented by the general formula (5) can be obtained.

(C) Platinum Group Metal Catalyst A catalyst for promoting an addition reaction (hydrosilylation) between the component (A) and the component (B). Examples include platinum-based, rhodium-based, ruthenium-based, iridium-based and palladium-based catalysts.

In general, a platinum-based catalyst that is relatively easily available is often used because it is a compound of a noble metal and is expensive. Examples of the platinum-based catalyst include chloroplatinic acid, complexes of chloroplatinic acid with olefins such as ethylene, complexes of alcohols and vinylsiloxanes, and 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 solution obtained by dissolving chloroplatinic acid or a complex thereof in a suitable solvent, in which the component is compatible with the component (A).

As a catalyst other than a platinum-based catalyst, for example, 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 use amount of these catalysts is not particularly limited, but may be expensive, and is generally about 1 to 1000 ppm, preferably about 10 to 500 ppm.

Other Components In putting the composition to practical use, various additives may be further added as 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
An organopolysiloxane having a resin structure consisting of units (wherein R represents a monovalent hydrocarbon group containing no aliphatic unsaturated double bond) (see JP-B-38-26771 and JP-B-45-9476); CH ₂ = added to control the cure rate of the composition
CHR ⁵ SiO unit (where R ⁵ has the same meaning as described above)
(See JP-B-48-10947)
And acetylene compounds (see U.S. Pat. No. 3,454,520 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 non-functional organopolysiloxane may be added for the purpose of improving thermal shock resistance, flexibility and the like.

When these additives are added, the aliphatic unsaturated group 1 directly bonded to the silicon atom in the whole composition is also added.
Per mole of organohydrogensiloxane (B)
The -H group must be present in 0.5 to 5 moles.

Further, the composition of the present invention contains a heat shrinkage during curing, a decrease in the coefficient of thermal expansion of an elastic material obtained by curing, a thermal stability, a weather resistance, a chemical resistance, a flame retardancy or a mechanical resistance. 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, a suitable pigment, dye or antioxidant can be added. In practical use of the composition of the present invention, the composition may be dissolved at a desired concentration in an appropriate organic solvent such as benzotrichloride, meta-xylene hexafluoride or the like depending on the use and purpose, and used.

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

[0033]

The composition of the present invention has a carbon atom of the Rf group in the main chain.
It is excellent in solvent resistance, water repellency and oil repellency because it is 11-30. When the main chain has a structural unit having — (CF ₂ ) _n —, a crystalline portion is formed in the cured rubber, so that the rubber strength is improved.

[0034]

Next, the present invention will be described in detail with reference to examples. In the following description, the viscosity indicates a value measured at 25 ° C.

Example 1 Formula (6):

Embedded image (Where a is about 25 on average and Rf is

Embedded image Or a group represented by the formula:

Embedded image Group represented by

A fluorocarbon siloxane polymer represented by the following formula (viscosity: 5700 cSt, average molecular weight: 25,000, vinyl group content:
0.008 mol / 100 g) To 100 parts by weight, 12 parts by weight of a fumed silica filler treated with a trimethylsiloxy group were added, mixed, heat-treated, and then mixed on a three-roll mill.

Embedded image (However, Rf is the formula:

Embedded image Is a group represented by

3.6 parts by weight of a Si—H group-containing fluorocarbon siloxane, 0.47 parts by weight of carbon black, and chloroplatinic acid are converted to CH ₂ CHCH—Si (CH ₃ ) ₂ —O—Si (CH ₃ ) ₂
Toluene solution (platinum concentration of the catalyst modified with -CH = CH ₂
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 evacuated again, 120 kgf / cm ² , 1
Press hardened at 50 ° C for 20 minutes. A test piece was cut out 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: Use A-type spring hardness tester specified in JIS K 6301) Measurement)

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

Embedded image (Where a is about 36 on average, c is about 4 on average, and Rf is

Embedded image And 100 parts by weight of a fluorocarbon siloxane polymer (viscosity: 6500 cSt, average molecular weight: 3100, vinyl group content: 0.007 mol / 100 g) represented by the formula (7) Instead of the Si-H group containing fluorocarbon siloxane of the formula)

Embedded image

(Where Rf is the formula:

Embedded image The composition was prepared in the same manner as in Example 1 except that 5.1 parts by weight was used to prepare a cured sheet. A test piece was cut out, and the physical properties were measured according to JIS K6301, 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:

Embedded image (Where Rf is the formula:

Embedded image Wherein a is an average of about 21 and b is an average of about 9)

A cured sheet was prepared in the same manner as in Example 1 except that 100 parts by weight (viscosity 5,900 cSt, vinyl group content 0.008 mol / 100 g) was used. A test piece was cut out and measured for physical properties according to JIS K6301. 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 results of a chemical resistance test of silicone rubber are also shown. From the above results, it is understood that the elastomer of the present invention is excellent in chemical resistance.

[0046]

[Table 2]

[0047]

[Table 3]

[0048]

The curable silicone composition of the present invention, when cured, gives a rubber elastic body having excellent solvent resistance, chemical resistance, water repellency and oil repellency and low moisture permeability. In addition, the composition is excellent in processability, and is particularly useful as a liquid rubber material for a gasket using a FIPG machine when a component (A) having a viscosity of 100,000 cSt or less is used.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Noriyuki Koike 1-10 Hitomi, Matsuida-machi, Usui-gun, Gunma Prefecture Inside Silicone Electronics Materials Research Laboratory Shin-Etsu Chemical Co., Ltd. (72) Inventor Takashi Matsuda Usui, Gunma Prefecture 1-10, Hitomi, Matsuida-cho, Gunnai Shin-Etsu Chemical Industry Co., Ltd. Silicone Electronic Materials Research Laboratory (72) Inventor Hirofumi Kinoshita 1-10, Hitomi, Matsuida-machi, Usui-gun, Gunma Prefecture Shin-Etsu Chemical Co., Ltd. (56) References JP-A-56-829 (JP, A) JP-A-52-85123 (JP, A)

Claims (1)

(57) [Claims] (A) General formula (1):[Wherein, R¹And R²Is an unsubstituted or substituted monovalent hydrocarbon
Group, R³Is a monovalent hydrocarbon group having 1 to 8 carbon atoms, and
Rf is the following general formula:-(CF₂CF₂OCF₂)_j− [CF (CF₃) OCF₂]_m− (CF₂)_n  − − [CF₂OCF (CF₃)]₁−(CF₂OCF₂CF₂)_k-(Where n is an integer from 0 to 8, m and 1 are integers from 0 to 5)
The numbers, j and k are integers of 0 or 1, provided that 1 + m + n
+ J + k is an integer having 11 to 30 carbon atoms)
Represented by a divalent perfluoroalkylene group or a divalent
A is a perfluoropolyether group, and a is 2 to 300.
An integer, b is an integer of 0 to 300, c is an integer of 0 to 5000
The number, p represents an integer from 2 to 8, and X represents the general formula:(Where R⁴Is an unsubstituted group having an aliphatic unsaturated bond or
Substituted monovalent hydrocarbon radical, R⁵And R⁶Is from 1 to 8 carbon atoms
Triorganosilyl group represented by monovalent hydrocarbon group)
Represented by an aliphatic unsaturated group-containing fluorocarbon siloxy group
Sun, (B) General formula (5):(Where Rf is as described above;⁷Is a carbon atom
Is a monovalent hydrocarbon group represented by the following formulas 1 to 8;
Which is an integer of 0 to 2).
Rocarbon siloxane,as well as And (C) a platinum group metal-based catalyst.
Per mole of the unsaturated unsaturated group in the composition,
A curable resin having an amount of i-H groups of 0.5 to 5.0 mol.
Recon composition.