JP2002322362A - Fluorine-containing curing composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a fluorine-containing curing composition. SOLUTION: This curing composition contains, as essential components, (A) a linear chain polyfluoro compound shown in the formula (1): CH2 =CH-(X)a - RF<1> -(X)a -CH=CH2 (1) [X is CH2 , CH2 O, CH2 OCH2 - or Y-NR<1> -CO; R<1> is H or a univalent hydrocarbon group; Rf<1> is a bivalent perfluoropolyether group; (a) is 0 or 1.], (B) a fluorine-containing organohydrogen siloxane shown in the formula (2) (Rf<2> is a univalent perfluoropolyether group; Z is a bivalent hydrocarbon group; Rf<3> is a perfluoroalkylene group or perfluoropolyether group; (w) and (x) are each an integer of 3 or less; 5>=w+x>=2; (y) is 0 or 1 and a+y>=1.), and (C) effective quantity of a platinum-group metallic catalyst. Accordingly, the curing compound provides a gel cured-product that has a superior compatibility of the (B) component with the (A) component as well as an excellence in adhesion to a substrate, resistance against solvents and chemicals.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention provides a gel cured product having excellent adhesion, chemical resistance and solvent resistance, and is suitable for potting, sealing materials, coating materials, etc. of electric and electronic parts. The present invention relates to a fluorine-containing curable composition that can be used for the present invention.

[0002]

2. Description of the Related Art A gel cured product of silicone rubber has excellent electric and thermal insulation properties.
Utilizes stable electrical properties and flexibility to protect materials for potting and encapsulation of electrical and electronic components, as well as control circuit elements such as power transistors, ICs, and capacitors from external thermal and mechanical damage. Used as a coating material for

A typical example of a silicone rubber composition which forms such a gel cured product is an addition-curable organopolysiloxane composition. This addition-curable organopolysiloxane composition contains, for example, an organopolysiloxane having a vinyl group bonded to a silicon atom and an organohydrogenpolysiloxane having a hydrogen atom bonded to a silicon atom, Known are those which obtain a silicone gel by performing a crosslinking reaction in the presence of a platinum-based catalyst (JP-A-56-143241 and JP-A-62-395).
9, JP-A-63-35655, JP-A-63-33475, etc.).

However, silicone gels obtained from these addition-curable organopolysiloxane compositions are easily swelled or deteriorated by chemicals such as strong bases and strong acids and solvents such as toluene, alcohol and gasoline. There was a problem that it was difficult to maintain performance.

In order to solve this problem, an organohydrogenpolysiloxane having a divalent perfluoropolyether group having two alkenyl groups in one molecule as a main component and having a hydrogen atom bonded to a silicon atom is used. -Gel composition containing platinum and a platinum-based catalyst, and a fluorine-gel cured product obtained by curing the same have been proposed (Japanese Patent Application Laid-Open No.
1-111685 gazette).

[0006] However, this fluorine gel cured product exhibits excellent chemical resistance and solvent resistance as compared with the silicone gel as intended, but has poor adhesion to substrates such as electric and electronic parts. It had the disadvantage of being weak.

In addition, when a perfluoropolyether having a large molecular weight is used as a main component, conventionally proposed organohydrogenpolysiloxanes have poor compatibility and have separation and destabilization of curability.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and a gel hardening composition having excellent compatibility of each component of a composition and excellent adhesion to a substrate, chemical resistance and solvent resistance. It is an object of the present invention to provide a fluorinated curable composition that gives a product.

[0009]

Means for Solving the Problems and Embodiments of the Invention The present inventors have made intensive studies to achieve the above object, and as a result, at least two alkenyl represented by the following general formula (1) as a base component. The combination of a linear polyfluoro compound having a group, a fluorinated organohydrogensiloxane represented by the following general formula (2), and a platinum group metal catalyst allows the compatibility of each component of the composition to be improved. The inventors have found that a fluorine-containing curable composition which is excellent and has excellent adhesiveness to a substrate and gives a gel cured product having excellent chemical resistance and solvent resistance can be obtained, and the present invention has been accomplished.

Accordingly, the present invention provides (A) a linear polyfluoro compound represented by the following general formula (1):
Compound, CH_Two= CH- (X)_a-Rf¹-(X)_a-CH = CH_Two (1) wherein X is independently -CH_Two-, -CH_TwoO-, -CH_Two
OCH_Two-Or -Y-NR ¹-CO- (where Y is -C
H_Two-Or

Embedded image R ¹ is a hydrogen atom or a substituted or unsubstituted monovalent hydrocarbon group), Rf ¹ is a divalent perfluoropolyether group, and a is independently 0 Or 1. ]

(B) a fluorine-containing organohydrogensiloxane represented by the following general formula (2)

Embedded image (Wherein X and a are the same as above, Rf ² is a monovalent perfluoropolyether group, Z is a divalent hydrocarbon group, and Rf ³ is a divalent perfluoroalkylene group or A perfluoropolyether group, w and x are 3
The following integer, and 5 ≧ w + x ≧ 2, and y is 0 or 1.
And a + y ≧ 1. )

(C) A fluorine-containing curable composition containing an effective amount of a platinum group metal catalyst as an essential component.

Hereinafter, the present invention will be described in more detail.
And the component (A) of the fluorine-containing curable composition of the present invention are as follows:
A linear polyfluoro compound represented by the general formula (1)
is there. CH_Two= CH- (X)_a-Rf¹-(X)_a-CH = CH_Two (1) wherein X is independently -CH_Two-, -CH_TwoO-, -CH_Two
OCH_Two-Or -Y-NR ¹-CO- (where Y is -C
H_Two-Or

Embedded image R ¹ is a hydrogen atom or a substituted or unsubstituted monovalent hydrocarbon group), Rf ¹ is a divalent perfluoropolyether group, and a is independently 0 Or 1. ]

In the formula (1), Rf ¹ is a divalent perfluoropolyether group, particularly preferably represented by the following formula.

Embedded image (Where p and q are integers of 1 or more, and 50 ≦ p + q
Satisfies ≦ 200, and r is an integer of 2 ≦ r ≦ 6. ),

[0015]

Embedded image (R is an integer of 2 ≦ r ≦ 6, s is an integer of s ≧ 0, t is t ≧
It is an integer of 0, and s and t satisfy 50 ≦ s + t ≦ 200. ) Or

[0016]

Embedded image (U is an integer of 50 ≦ u ≦ 200, and v is an integer of 1 ≦ v ≦ 50.)

Specific examples of such Rf ¹ include the following.

Embedded image

In the formula (1), X is independently -CH
_{2 -, - CH 2 O -} , - CH 2 OCH 2 - or -Y-NR ¹
—CO—. Here, Y is —CH ₂ — or the following group.

Embedded image

R ¹ is a hydrogen atom or a substituted or unsubstituted monovalent hydrocarbon group. The monovalent hydrocarbon group preferably has 1 to 12 carbon atoms, particularly 1 to 10 carbon atoms. The alkyl group such as methyl group, ethyl group, propyl group, butyl group, hexyl group, cyclohexyl group, octyl group, phenyl group, aryl group such as tolyl group,
Unsubstituted monovalent hydrocarbon groups such as aralkyl groups such as benzyl group and phenylethyl group, and substituted monovalent hydrocarbon groups in which some or all of the hydrogen atoms of these groups are substituted with halogen atoms such as fluorine. Can be

The alkenyl group in the above formula (1) is preferably, for example, a vinyl group having a —CH ＝ CH ₂ structure at a terminal, an allyl group, or the like. This alkenyl group is
It may be directly bonded to both ends of the main chain, or may be bonded via a divalent linking group represented by the above formula X.

In the formula (1), a is independently 0 or 1.

The composition of the present invention may be cast, potted,
For use in coating, impregnation, adhesion or the like, it is preferable that the material has appropriate fluidity and that the cured product also has appropriate physical properties. From this point of view,
The viscosity (23 ° C.) of the component (A) is from 5 to 100,00
The viscosity is desirably in the range of 0 mPa · s, and desirably has the most appropriate viscosity in the above-mentioned viscosity range depending on the application.

Next, the component (B) of the present invention is a fluorine-containing organohydrogensiloxane represented by the following general formula (2).

Embedded image (Wherein X and a are the same as above, Rf ² is a monovalent perfluoropolyether group, Z is a divalent hydrocarbon group, and Rf ³ is a divalent perfluoroalkylene group or A perfluoropolyether group, w and x are 3
The following integer, and 5 ≧ w + x ≧ 2, and y is 0 or 1.
And a + y ≧ 1. )

Here, in the formula (2), Rf ² is a monovalent perfluoropolyether group, and preferably represented by the following formula.

Embedded image

Specific examples of such Rf ² include the following.

Embedded image

In the formula (2), X and a are the same as those shown in the formula (1). In this case, equation (1)
X and a in the formula (2) may be the same as or different from each other.

Z is a divalent hydrocarbon group, and preferably has 1 carbon atom such as an alkylene group such as a methylene group, an ethylene group, a propylene group, a methylethylene group, and a tetramethylene group, and an arylene group such as a phenylene group. And particularly preferably a divalent hydrocarbon group having 1 to 5 carbon atoms.
Further, Rf ³ is a divalent perfluoroalkylene group or a perfluoropolyether group, and particularly includes those represented by the following general formula.

[0028]

Embedded image

W and x are integers of 3 or less, and 5 ≧ w + x
≧ 2, y is 0 or 1, and a + y ≧ 1
It satisfies.

The fluorine-containing organohydrogensiloxane of the component (B) of the present invention functions as a crosslinking agent and a chain extender of the component (A), and has at least two hydrosilyl groups (Si) in one molecule. —H group). Further, in consideration of the compatibility with the component (A), the dispersibility, and the uniformity after curing, those having at least one Rf ² linking group in one molecule are preferable. Examples of such a fluorinated organohydrogensiloxane include the following compounds. These compounds may be used alone or in combination of two or more.

[0031]

Embedded image

[0032]

Embedded image

The amount of the component (B) is based on 1 mole of an aliphatic unsaturated group such as a vinyl group or an allyl group contained in the entire system of the composition, and the hydrosilyl group of the component (B), that is, the Si—H group is used. Is preferably 0.2 to 2 mol, more preferably 0.5 to 2 mol.
1.3 mol can be supplied. (B) Component Si-H
If the group is less than 0.2 mol, the degree of crosslinking may be insufficient and a cured gel may not be obtained.
If the group is present in an amount greater than 2 mol, foaming may occur during curing.

As a method for obtaining the component (B) of the present invention, a polyfunctional SiH compound represented by the following general formula (i) is added to an alkenyl group-containing fluorine compound represented by the following general formula (ii) and a platinum compound or the like. Can be synthesized in the presence of an addition reaction catalyst.

Embedded image (However, Rf ³ , z, x, a, and y have the same meaning as described above.)

In this case, (i) for the compound of (i)
The addition amount of the compound of i) is as follows in the compound of formula (2):
w and x are appropriately selected so as to have the above-described relationship.

Further, the platinum group metal catalyst of the component (C) of the present invention is a catalyst for accelerating the addition reaction between the aliphatic unsaturated group in the component (A) and the hydrosilyl group in the component (B). is there. This platinum group metal catalyst is generally a compound of a noble metal and is expensive, so that a platinum compound which is relatively easily available is often used.

Examples of the platinum compound include chloroplatinic acid or a complex of chloroplatinic acid and an olefin such as ethylene, a complex of alcohol or vinyl siloxane, platinum / silica, alumina or carbon. However, the present invention is not limited to this. As platinum group metal catalysts other than platinum compounds, rhodium, ruthenium, iridium,
Palladium compounds are also known, for example, RhCl
(PPh ₃ ) ₃ , RhCl (CO) (PPh ₃ ) ₂ , Ru ₃
(CO) ₁₂ , IrCl (CO) (PPh ₃ ) ₂ , Pd (P
Ph ₃ ) _{4 and the} like.

The amount of the platinum group metal catalyst can be a catalytic amount, but is usually 10% in total of the components (A) and (B).
It is preferable to mix at 0.1 to 100 ppm with respect to 0 parts by weight.

In the composition of the present invention, the above (A) to
Various known additives can be added in addition to the component (C). Such optional components include, for example, 1-ethynyl-1-hydroxycyclohexane, 3-methyl-1
Acetylene alcohols such as -butyn-3-ol, 3,5-dimethyl-1-hexyn-3-ol, 3-methyl-1-penten-3-ol, and phenylbutynol; and 3-methyl-3-pentene- Control agents for hydrosilylation reaction catalysts such as 1-yne, 3,5-dimethyl-3-hexen-1-yne, etc., or polymethylvinylsiloxane cyclic compounds, organophosphorus compounds, etc. Storage stability can be kept moderate.
Further, for example, fumed silica, silica aerosil, precipitated silica, ground silica, diatomaceous earth, iron oxide, zinc oxide,
The hardness and mechanical strength of the cured gel obtained from the composition of the present invention can be adjusted by adding an inorganic filler such as titanium oxide, calcium carbonate, magnesium carbonate, zinc carbonate and carbon black. Of course hollow inorganic fillers,
Hollow organic fillers or rubbery spherical fillers can also be added. Further, by adding a perfluoropolyether oil having good compatibility and having no reactive functional group to the present composition, the viscosity of the composition and the hardness of the obtained cured product can be adjusted. The amounts of these components used are arbitrary as long as the physical properties of the obtained cured gel are not impaired.

Further, a linear polyfluoro compound represented by the following general formula (3) can be used in combination with the component (A). Use of this component is useful in terms of characteristics to obtain a cured gel.

Rf ² — (X) _a —CH ＝ CH ₂ (3) (where X, a and Rf ² are the same as above)

The alkenyl group in the above formula (3) is preferably a vinyl group or an allyl group having a —CH 末端 CH ₂ structure at the terminal similarly to the component (A), and is directly bonded to the main chain. Or a bond via a divalent linking group represented by the above formula X.

The fluorinated curable composition of the present invention comprising the above-described components can be cured to form a cured gel having excellent solvent resistance and chemical resistance.

In the present invention, the cured gel is defined as
A material having a partially three-dimensional structure and exhibiting deformation and fluidity due to stress, and having a hardness of not more than "0" in a JIS rubber hardness meter as a rough guide, or ASTM D-1403 ( (１ ／ cone) with a penetration of 1 to 200.

The cured gel can be formed by injecting the addition-curable composition of the present invention into a suitable mold to cure the composition, or by coating the composition on a suitable substrate and then curing the composition. And so on by a conventionally known method. Curing can be easily performed by heat treatment at a temperature of usually 60 to 150 ° C. for about 30 to 180 minutes.

[0046]

The fluorinated curable composition of the present invention is characterized in that the fluorinated organohydrogensiloxane, which is a curing agent, has excellent compatibility with the base material, as well as adhesion to the substrate, solvent resistance and chemical resistance. It gives a cured gel with excellent properties and is suitable for potting and sealing electric and electronic parts, and also as a protective coating for control circuit elements such as power transistors, ICs and capacitors. can do.

[0047]

EXAMPLES The present invention will be described below in detail with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples.

Example 1 60 parts by weight of a polymer represented by the following formula (4) (viscosity of 10,000 cP) and 40 of a polymer represented by the following formula (5) (viscosity of 1,000 cP):
20 parts by weight of a compound represented by the following formula (6)
50% toluene solution of ethynylcyclohexanol
15 parts by weight and 0.015 parts by weight of an ethanol solution of a vinylsiloxane complex of chloroplatinic acid (platinum concentration: 3.0% by weight) were added and mixed to prepare a fluorinated cured composition. The appearance of this composition was transparent, and the transparency did not change even when left at 25 ° C. for 24 hours.

[0049]

Embedded image

The composition was heated at 150 ° C. for 1 hour,
When cured, the penetration was 70 (ASTM D-140
(3 コ ー ン cone) was obtained.

Example 2 70 parts by weight of a polymer represented by the following formula (7) instead of the polymer of the formula (4) in Example 1, and a polymer represented by the following formula (8) instead of the polymer of the formula (5) A composition was prepared in the same manner as in Example 1, except that 30 parts by weight of the compound represented by the following formula (9) was used instead of 30 parts by weight of the compound represented by the formula (6). The appearance of this composition was transparent, and the transparency did not change even when left at 25 ° C. for 24 hours.

[0052]

Embedded image

When this composition was cured in the same manner as in Example 1, the penetration was 60 (ASTM D-1403 1/4).
A clear gel cured product (cone) was obtained.

Example 3 A composition was prepared in the same manner as in Example 1 except that 18 parts by weight of the compound represented by the following formula (10) was used instead of the polymer of the formula (6) in Example 1. . The appearance of this composition was transparent, and the transparency did not change even when left at 25 ° C. for 24 hours.

[0055]

Embedded image

When this composition was cured in the same manner as in Example 1, the penetration was 65 (ASTM D-1403 1/4).
(Cone) was obtained.

Comparative Example 1 A composition was prepared in the same manner as in Example 1 except that 10 parts by weight of the compound represented by the following formula (11) was used instead of the compound of the formula (6) in Example 1. . The appearance of this composition is cloudy,
After standing for a period of time, the composition had separated into two layers.

[0058]

Embedded image

When this composition was cured in the same manner as in Example 1, a cloudy and unevenly cured gel cured product was obtained.

Reference Example 1 A 1 L four-necked flask equipped with a stirrer, a thermometer, a cooling tube and a dropping funnel was charged with 370 g of the compound of the following formula (a) and 200 g of toluene, and heated to 80 ° C. Then, a toluene solution of a vinylsiloxane complex of chloroplatinic acid (platinum concentration 0.5% by weight)
0.1 g of a compound 700 of the following formula (b)
g was dropped with a dropping funnel.

[0061]

Embedded image

After completion of the dropwise addition, the mixture was aged at 80 ° C. for 1 hour, and after confirming that the compound (b) was consumed by gas chromatography, the mixture was cooled.

Thereafter, 10 g of activated carbon was added, and the mixture was stirred for 1 hour, filtered, and the obtained filtrate was heated at 120 ° C./3 Torr.
The solvent was removed by stripping under the conditions of
990 g of a colorless and transparent liquid (viscosity 28 cs, specific gravity 1.327, refractive index 1.364) was obtained.

When this liquid was analyzed by ¹ H-NMR, IR and elemental analysis, it was confirmed that it was a compound having an average structure represented by the following formula (c).

[0065]

Embedded image

¹ H-NMR δ 0.09 (s, C-Si- CH ₃ : 12H) δ 0.16 (s, H-Si- CH ₃ : 24H) δ 0.6-1.3 (m, Si- CH _{2 -: 8H) δ1.5~2.3 (m} , Si-CH 2 - CH 2 - CH
_2- : 8H) δ 4.72 (s, Si- H : 4H)

IR 2130 cm ^-1 ν _Si-H

Elemental analysis C H O Si F Actual value (%) 29.4 3.8 6.7 15.6 44.5 Theoretical value (%) 29.7 3.9 6.6 15.4 44.4

REFERENCE EXAMPLE 2 115 g of the compound of the formula (a) and 100 g of bistrifluoromethylbenzene were charged into a 1 L four-necked flask equipped with a stirrer, a thermometer, a cooling tube and a dropping funnel, and heated to 80 ° C. did. afterwards,
0.03 g of a toluene solution of a chloroplatinic acid vinylsiloxane complex (platinum concentration: 0.5% by weight) was added, and 1850 g of the compound of the following formula (d) was further added dropwise using a dropping funnel.

[0070]

Embedded image

After completion of the dropwise addition, the mixture was aged at 80 ° C. for 1 hour and cooled.

Then, after adding 10 g of activated carbon and stirring for 1 hour, the mixture was filtered, and the obtained filtrate was heated at 120 ° C./3 Torr.
The solvent was removed by stripping under the conditions of
Colorless and transparent liquid (viscosity 2520 cs, specific gravity 1.709,
1050 g of a refractive index (1.333) was obtained.

When this liquid was analyzed by ¹ H-NMR, IR and elemental analysis, it was confirmed that the compound had an average structure represented by the following formula (e).

[0074]

Embedded image

¹ H-NMR δ 0.09 (s, C-Si- CH ₃ : 6H) δ 0.16 (s, H-Si- CH ₃ : 30H) δ 0.31 (s, arom. Si- CH ₃ : 6H) δ0.6~1.3 (m, Si- CH 2 -: 8H) δ3.23 (s, N- CH 3: 3H) δ4.72 (s, Si- H: 5H) δ7.2~7 0.7 (m, arom .: 4H)

IR 2130 cm ^-1 ν _Si-H

Elemental analysis C H O Si F N Actual value (%) 24.9 1.4 10.3 5.1 58.0 0.3 Theoretical value (%) 24.7 1.3 10.2 5. 258.3 0.3

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Claims (3)

[Claims] (A) a straight chain represented by the following general formula (1)
Polyfluoro compound, CH_Two= CH- (X)_a-Rf¹-(X)_a-CH = CH_Two (1) wherein X is independently -CH_Two-, -CH_TwoO-, -CH_Two
OCH_Two-Or -Y-NR ¹-CO- (where Y is -C
H_Two-OrA divalent group represented by¹Is a hydrogen atom or
Or an unsubstituted monovalent hydrocarbon group), Rf¹Is divalent
A is independently 0 or
Is 1. (B) a fluorine-containing organowater represented by the following general formula (2)
Silicon siloxane(Wherein X and a are the same as above, and Rf^TwoIs monovalent
Z is a divalent hydrocarbon
Rf^ThreeIs a divalent perfluoroalkylene group
Or a perfluoropolyether group, w and x are 3
The following integer, and 5 ≧ w + x ≧ 2, and y is 0 or 1.
And a + y ≧ 1. (C) contains an effective amount of a platinum group metal catalyst as an essential component
Fluorine-containing curable composition. 2. In the above general formula (1), Rf ¹ is represented by the following formula: (Where p and q are integers of 1 or more, and 50 ≦ p + q
Satisfies ≦ 200, and r is an integer of 2 ≦ r ≦ 6. ), Embedded image (R is an integer of 2 ≦ r ≦ 6, s is an integer of s ≧ 0, and t is t ≧
0 and s and t are 50 ≦ s + t ≦ 200
Meet. ) Or The curable composition according to claim 1, wherein u is an integer of 50 ≦ u ≦ 200, and v is an integer of 1 ≦ v ≦ 50. 3. The curable composition according to claim 1, wherein the cured product obtained after curing has a penetration (ASTM D-1403) in the range of 1 to 200.