JP5516515B2 - Room temperature curable fluoropolyether rubber composition and cured product thereof - Google Patents

Description

  TECHNICAL FIELD The present invention relates to an amide-crosslinking type room temperature curable fluoropolyether rubber composition and a cured product thereof, and more specifically, a siloxane polymer containing at least three amino groups in one molecule as a crosslinking agent component. Room temperature curable fluoropolyether rubber composition excellent in long-term storage stability that suppresses inhibition of curing caused by moisture absorption in the air over time and maintains initial curing characteristics and post-curing physical properties, and curing thereof Related to things.

（式中、ａは３〜５０、好ましくは３〜２０、ｂは１〜５０、好ましくは１〜１０、ａ＋ｂ＝４〜１００、ｃは０〜１００、好ましくは１〜３０を満足する整数である。） The room temperature curable fluoropolyether rubber composition cures in a relatively short time at room temperature, and gives a cured product excellent in heat resistance, low temperature, chemical resistance, solvent resistance, oil resistance, etc. It is expected to be applied to large parts that do not enter the heating furnace, parts that cannot be heated, and sealing materials that require chemical resistance and solvent resistance.
The present applicant previously described in Japanese Patent Application Laid-Open No. 2011-57809 (Patent Document 1) as a curing agent component of a room temperature curable fluoropolyether rubber composition, for example, a part of an amino group represented by the following general formula: It was shown that a fluorine-modified amino group-containing organopolysiloxane introduced with a fluorine-modified group can be employed. This polymer is liquid at room temperature, has a number of primary amino groups in one molecule, and has good dispersibility in a fluoropolymer due to fluorine-modified groups. It acts satisfactorily as a crosslinking agent component in the polyether rubber composition.
However, the fluorine-modified amino group-containing organopolysiloxane absorbs moisture over time in the air, and the composition causes inhibition of curing due to the influence of the moisture-absorbing water. There has been a problem that physical properties such as hardness of the cured product may be adversely affected.

(In the formula, a is 3 to 50, preferably 3 to 20, b is 1 to 50, preferably 1 to 10, a + b = 4 to 100, c is an integer satisfying 0 to 100, preferably 1 to 30. is there.)

JP 2011-57809 A

  The present invention has been made in view of the above circumstances, and is an amide crosslinking type room temperature curable fluoropolyether rubber composition and a cured product thereof, in which at least 3 amino groups are contained in one molecule as the crosslinking agent component. Room-temperature curable fluoropolyether rubber with excellent long-term storage stability that can suppress the inhibition of curing caused by moisture absorption in the air over time, and maintain initial curing characteristics and physical properties after curing It aims at providing a composition and its hardened | cured material.

  As a result of intensive studies to achieve the above object, the present inventors have blended a molecular sieve having an average particle size of 30 μm or less with a crosslinking agent component of a conventional room temperature curable fluoropolyether rubber composition. Room temperature curable fluoropolypropylene with excellent long-term storage stability, which suppresses curing inhibition caused by moisture absorption over time in the air, and maintains initial curing characteristics and post-curing physical properties. The inventors have found that an ether rubber composition and a cured product thereof can be obtained, and have made the present invention.

（式中、ｐ及びｑは１〜１５０の整数であって、かつｐとｑの和は、２〜２００である。また、ｒは０〜６の整数、ｔは２又は３である。）

（式中、ｕは１〜２００の整数、ｖは１〜５０の整数、ｔは上記と同じである。）

（式中、ｘは１〜２００の整数、ｙは１〜５０の整数、ｔは上記と同じである。）
（ｂ）１分子中にアミノ基を少なくとも３個含有するシロキサンポリマー：（ｂ）成分中のアミノ基の合計量／（ａ）成分中のエステル基の合計量＝１．０〜５．０（モル比）となる量、及び
（ｃ）平均粒径が３０μｍ以下のモレキュラーシーブ：（ｂ）成分１００質量部に対し１〜２０質量部
を含有してなることを特徴とする室温硬化性フルオロポリエーテル系ゴム組成物。
請求項２：
（ａ）成分を主成分とするベースコンパウンドと（ｂ）及び（ｃ）成分を主成分とする架橋剤コンパウンドとからなる二成分型である請求項１記載の室温硬化性フルオロポリエーテル系ゴム組成物。
請求項３：
（ｂ）成分が、下記式（ｉｖ）〜（ｖｉｉ）のアミノ基含有シロキサンポリマーから選ばれることを特徴とする請求項１又は２記載の室温硬化性フルオロポリエーテル系ゴム組成物。

（式中、ｎは３〜５０の整数である。）

（式中、ｎは３〜５０の整数である。）

（式中、ａは３〜５０、ｂは１〜５０、ａ＋ｂ＝４〜１００、ｃは０〜１００を満足する整数である。）

（式中、ａは３〜５０、ｂは１〜５０、ａ＋ｂ＝４〜１００、ｎは１〜１０を満足する整数である。）
請求項４：
請求項１〜３のいずれか１項記載の室温硬化性フルオロポリエーテル系ゴム組成物を硬化させることにより得られることを特徴とする硬化物。 Accordingly, the present invention provides the following room temperature curable fluoropolyether rubber composition and its cured product.
Claim 1:
(A) Number average molecular weight of 3,000 to 100 represented by the following general formula (1) having at least two ester groups in one molecule and having a divalent perfluoroalkyl ether structure in the main chain , 1,000 linear fluoropolyether compound: 100 parts by mass,
ROOC-Rf-COOR '(1)
(In the formula, Rf is a divalent perfluoroalkyl ether structure selected from the following formulas (i) to (iii), and R and R ′ are the same or different 1 to 8 substituted or unsubstituted 1 to 8 carbon atoms. Valent hydrocarbon group.)

(In the formula, p and q are integers of 1 to 150, and the sum of p and q is 2 to 200. Also, r is an integer of 0 to 6, and t is 2 or 3.)

(In the formula, u is an integer of 1 to 200, v is an integer of 1 to 50, and t is the same as above.)

(In the formula, x is an integer of 1 to 200, y is an integer of 1 to 50, and t is the same as above.)
(B) Siloxane polymer containing at least three amino groups in one molecule: (b) Total amount of amino groups in component / (a) Total amount of ester groups in component = 1.0 to 5.0 ( Molar ratio) and (c) molecular sieve having an average particle size of 30 μm or less: (b) 1 to 20 parts by mass per 100 parts by mass of component Ether-based rubber composition.
Claim 2:
2. The room temperature curable fluoropolyether rubber composition according to claim 1, which is a two-component type comprising a base compound mainly composed of component (a) and a crosslinker compound composed mainly of components (b) and (c). object.
Claim 3:
The room temperature curable fluoropolyether rubber composition according to claim 1 or 2, wherein the component (b) is selected from amino group-containing siloxane polymers represented by the following formulas (iv) to (vii).

(In the formula, n is an integer of 3 to 50.)

(In the formula, n is an integer of 3 to 50.)

(In the formula, a is 3 to 50, b is 1 to 50, a + b = 4 to 100, and c is an integer satisfying 0 to 100.)

(In the formula, a is 3 to 50, b is 1 to 50, a + b = 4 to 100, and n is an integer satisfying 1 to 10. )
請 Motomeko 4:
A cured product obtained by curing the room temperature-curable fluoropolyether rubber composition according to any one of claims 1 to 3 .

  According to the present invention, the crosslinking agent component of the conventional room temperature curable fluoropolyether rubber composition suppresses the inhibition of curing caused by moisture absorption over time in the air, and improves the initial curing characteristics and post-curing physical properties. A room temperature curable fluoropolyether rubber composition excellent in long-term storage stability that can be maintained and a cured product thereof can be provided.

It is a graph regarding the evaluation of room temperature curability after storage for 2 months and 5 months at 30 ° C. and 90% RH in the initial stage with the compositions of Examples. It is a graph regarding evaluation of room temperature curability after storage for 2 months and 5 months at 30 ° C. and 90% RH in the initial stage with the composition of the comparative example. It is a graph regarding hardness among the hardened | cured material physical properties after an initial stage by 30 degreeC and 90% RH for 2 months and 5 months by each composition of an Example and a comparative example. It is a graph regarding tensile strength among the hardened | cured material physical properties after an initial stage by 30 degreeC and 90% RH for 2 months and 5 months by each composition of an Example and a comparative example. It is a graph regarding the elongation at the time of cutting among the hardened | cured material physical properties after an initial stage by 30 degreeC and 90% RH for 2 months and 5 months by each composition of an Example and a comparative example.

Hereinafter, the present invention will be described in more detail.
The room temperature curable fluoropolyether rubber composition of the present invention comprises (a) a linear fluoropolyether compound, (b) an amino group-containing siloxane polymer, and (c) a molecular sieve as essential components.

(A) Linear fluoropolyether compound The linear fluoropolyether compound of component (a) is a main component polymer (base polymer) of a room temperature curable fluoropolyether rubber composition, and at least in one molecule The number average molecular weight having two ester groups and having a divalent perfluoroalkyl ether structure in the main chain is in the range of 3,000 to 100,000, preferably at both ends of the molecular chain. Each is a linear fluoropolyether compound having an ester group.

Examples of the component (a) include compounds represented by the following general formula (1).
ROOC-Rf-COOR '(1)
(In the formula, Rf is a divalent perfluoroalkyl ether structure selected from the following formulas (i) to (iii) , and R and R ′ are the same or different 1 to 8 substituted or unsubstituted 1 to 8 carbon atoms. Valent hydrocarbon group.)

  Here, examples of the divalent perfluoroalkyl ether structure include structures represented by the following general formulas (i), (ii), and (iii).

（式中、ｐ及びｑは１〜１５０の整数であって、かつｐとｑの和は、２〜２００である。また、ｒは０〜６の整数、ｔは２又は３である。）

(In the formula, p and q are integers of 1 to 150, and the sum of p and q is 2 to 200. Also, r is an integer of 0 to 6, and t is 2 or 3.)

（式中、ｕは１〜２００の整数、ｖは１〜５０の整数、ｔは上記と同じである。）

(In the formula, u is an integer of 1 to 200, v is an integer of 1 to 50, and t is the same as above.)

（式中、ｘは１〜２００の整数、ｙは１〜５０の整数、ｔは上記と同じである。）

(In the formula, x is an integer of 1 to 200, y is an integer of 1 to 50, and t is the same as above.)

  The substituted or unsubstituted monovalent hydrocarbon group R or R ′ in the ester group in the linear fluoropolyether compound of component (a) has 1 to 8 carbon atoms, particularly 1 to 3 carbon atoms. Preferably, for example, alkyl groups such as methyl group, ethyl group, normal propyl group, isopropyl group, butyl group, isobutyl group, tert-butyl group, hexyl group, cyclohexyl group, octyl group, 2-ethylhexyl group, vinyl group, allyl group An alkenyl group such as a group or a group in which a part of hydrogen atoms of these groups is substituted with a halogen atom such as fluorine, chlorine, bromine or iodine is preferable, and an alkyl group having 1 to 3 carbon atoms is particularly preferable.

  The linear fluoropolyether compound of the component (a) is, for example, a polystyrene-equivalent number average by gel permeation chromatography (GPC) using a fluorine-based organic solvent such as hydrochlorofluorocarbon (HCFC) -225 as a developing solvent. The molecular weight is desirably 3,000 to 100,000, particularly 3,000 to 50,000. If the number average molecular weight is less than 3,000, the mechanical strength may be inferior, and if the number average molecular weight exceeds 100,000, the workability may be inferior.

  Specific examples of the linear fluoropolyether compound represented by the general formula (1) include those represented by the following formula. These compounds may be used alone or in combination of two or more. May be.

（式中、ｍ及びｎはそれぞれ０〜６００，ｍ＋ｎ＝２０〜６００、ｈ、ｉ、ｊ及びｋはｈ＋ｉ＋ｊ＋ｋ＝２０〜１，０００を満足する整数を示す。）

(In the formula, m and n are 0 to 600, m + n = 20 to 600, h, i, j and k are integers satisfying h + i + j + k = 20 to 1,000, respectively.)

(B) Amino group-containing siloxane polymer The amino group-containing siloxane polymer of the component (b) acts as a crosslinking agent and a chain length extender of the component (a). There is no particular limitation as long as it is a siloxane polymer containing at least three amino groups, particularly primary amino groups in one molecule.

  In addition, in order to improve the dispersibility of the siloxane polymer of the component (b) in the component (a), one or more fluorine-modified groups may be introduced into an amino group as required. Examples of the fluorine-modified group herein include a monovalent perfluoroalkyl group and a monovalent perfluoroalkyl ether group, and the molecular structure may be either a chain or a branched structure. Representative examples thereof include groups represented by the following general formula, but are not limited thereto.

（式中、ｇは１〜６、好ましくは４〜６の整数である。）

(In the formula, g is an integer of 1 to 6, preferably 4 to 6.)

（式中、ｆは２〜２００、好ましくは２〜１００、ｈは１〜３の整数である。）

(In the formula, f is 2 to 200, preferably 2 to 100, and h is an integer of 1 to 3.)

（式中、ｄ及びｅはそれぞれ１〜５０の整数である。）

(In the formula, d and e are each an integer of 1 to 50.)

  These perfluoroalkyl groups and perfluoroalkyl ether groups are, for example, the following fluorine-containing terminal ester compounds and can be introduced into the amino group of the amino group-containing siloxane polymer by dealcoholization reaction or the like according to JP-A-7-18079. . However, the terminal ester compound is not limited to the following.

（式中、ｇは１〜６、好ましくは４〜６の整数である。）

(In the formula, g is an integer of 1 to 6, preferably 4 to 6.)

（式中、ｆは２〜２００、好ましくは２〜１００、ｈは１〜３の整数である。）

(In the formula, f is 2 to 200, preferably 2 to 100, and h is an integer of 1 to 3.)

（但し、ｄ及びｅはそれぞれ１〜５０の整数である。）

(However, d and e are each an integer of 1 to 50.)

The amino group of the component (b) amino group-containing siloxane polymer is preferably a primary amino group (—NH ₂ ), and the number of amino groups in the molecule, particularly the number of primary amino groups in the siloxane polymer is particularly limited. However, it is usually 3 to 100, preferably 3 to 50, and particularly preferably about 4 to 20.

  Such an amino group-containing siloxane polymer may have, for example, a linear, cyclic, or branched siloxane structure, and the number of silicon atoms in the molecule is usually 3 to 200, Preferably, it may be about 4 to 100. Examples of the amino group-containing siloxane polymer as the component (b) include the following compounds, and these compounds may be used alone or in combination of two or more.

（式中、ｎは３〜５０、好ましくは３〜３０の整数である。）

(In the formula, n is an integer of 3 to 50, preferably 3 to 30.)

（式中、ｎは３〜５０、好ましくは３〜３０の整数である。）

(In the formula, n is an integer of 3 to 50, preferably 3 to 30.)

（式中、ａは３〜５０、好ましくは３〜２０、ｂは１〜５０、好ましくは１〜１０、ａ＋ｂ＝４〜１００、ｃは０〜１００、好ましくは１〜３０を満足する整数である。）

(In the formula, a is 3 to 50, preferably 3 to 20, b is 1 to 50, preferably 1 to 10, a + b = 4 to 100, c is an integer satisfying 0 to 100, preferably 1 to 30. is there.)

（式中、ａは３〜５０、好ましくは３〜２０、ｂは１〜５０、好ましくは１〜１０、ａ＋ｂ＝４〜１００、ｎは１〜１０、好ましくは１〜６を満足する整数である。）

(In the formula, a is 3 to 50, preferably 3 to 20, b is 1 to 50, preferably 1 to 10, a + b = 4 to 100, and n is an integer satisfying 1 to 10, preferably 1 to 6. is there.)

（式中、ａは３〜５０、好ましくは３〜２０、ｂは１〜５０、好ましくは１〜１０、ｄは１〜５０、好ましくは１〜１０、ａ＋ｂ＋ｄ＝４〜１００、ｃは０〜１０、好ましくは１〜５、ｅは１１〜１００、好ましくは２０〜５０を満足する整数である。）

(Wherein, a is 3 to 50, preferably 3 to 20, b is 1 to 50, preferably 1 to 10, d is 1 to 50, preferably 1 to 10, a + b + d = 4 to 100, and c is 0 to 0. 10, preferably 1 to 5, e is an integer satisfying 11 to 100, preferably 20 to 50)

  The blending amount of component (b) is usually an amino group (particularly 1) in component (b) relative to the total amount of ester groups such as methyl ester group, ethyl ester group, propyl ester group and the like contained in component (a). The ratio of the total amount of (primary amino groups) is preferably 1.0 to 5.0 (molar ratio), more preferably 2.0 to 4.0 (molar ratio). If the molar ratio is less than 1.0, the degree of cross-linking may be insufficient and the mechanical strength may be inferior. If the molar ratio is more than 5.0, the chain length extension is prioritized and the cured product properties are insufficient and satisfactory. It may not be obtained. Moreover, this (b) component may be used individually by 1 type, and may use 2 or more types together.

(C) Molecular sieve The molecular sieve of component (c) is a crystalline zeolite that has fine pores of molecular diameter level, and water molecules are taken into the pores to dehydrate the system. (Dry). In the present invention, by preparing a cross-linking agent compound in which the component (c) is added in advance to the component (b), moisture absorption in the component (b) is collected, and good storage stability is imparted. It becomes possible.

  There are various grades of molecular sieves depending on the size of the pores. The preferred grade is 3A or 4A based on its ability to adsorb moisture, but it is not limited to this.

There are various types of molecular sieves, such as mesh (pulverized) and powder (powder) that do not contain the binder component activated as it is, and pellets (long column) and beads (spherical) that contain the binder component. In order to obtain good storage stability without impairing the curing characteristics and physical properties after curing, a mesh type or a powder type containing no binder component, particularly a powder type is preferred.
The molecular sieve preferably has an average particle size of 30 μm or less, particularly 10 μm or less. Even in the powder type, when the average particle size is larger than 30 μm, it is difficult to uniformly disperse in the rubber composition, and the physical properties after curing are adversely affected. The lower limit of the average particle diameter is not particularly limited, but is usually 0.1 μm or more, particularly 0.5 μm or more.
Here, the average particle diameter can be measured as a cumulative weight average diameter D ₅₀ (or median diameter) or the like in a measurement by an electron microscope or a particle size distribution measurement by a laser light diffraction method.

  The compounding amount of the molecular sieve when producing the crosslinking agent compound is 1 to 20 parts by mass, more preferably 1 to 10 parts by mass with respect to 100 parts by mass of the component (b). When the blending amount is less than 1 part by mass, good storage stability cannot be imparted. Conversely, when the blending amount is more than 20 parts by mass, the viscosity increases and the workability is inferior. Inconvenience such as exerting occurs.

Other Components The component (a) preferably forms a base compound with this as the main component, and the components (b) and (c) preferably form a cross-linking agent compound with these as the main components. Here, a main component means the component which occupies the compounding ratio of 50 to 100 mass% in a base compound or a crosslinking agent compound.
Such a base compound and a crosslinking agent compound can be blended by a known method using various known fillers and additives as other components as long as the effects of the present invention are not impaired.

  Specific examples of such other components include fillers such as fumed silica, crystalline silica and calcium carbonate, pigments such as iron oxide, cerium oxide and carbon black, colorants, dyes, antioxidants, Examples of the viscosity modifier include oily compounds partially or entirely modified with fluorine.

  In order to improve the rubber strength after the cured product, the base compound is preferably blended with the filler, and the blending amount is usually 5 to 70 parts by mass with respect to 100 parts by mass of the component (a). In particular, the amount is preferably 10 to 50 parts by mass.

In order to improve and stabilize the dispersibility of the component (c) in the component (b), the crosslinking agent compound is preferably blended with the above-mentioned filler, and the blending amount is 100 parts by weight of the component (b). On the other hand, it is usually preferably 1 to 50 parts by mass, particularly 10 to 30 parts by mass.
Moreover, it is preferable to mix | blend the said viscosity modifier in the case of finally mixing a base compound with a crosslinking agent compound, The compounding quantity is 1 to 100 mass parts of (b) component normally. It is preferable to set it as 100 mass parts, especially 20-80 mass parts.

Method of Use It is preferable that the composition of the present invention comprises the above-mentioned base compound and cross-linking agent compound separately to form a two-component type, and these are uniformly mixed by a known method in use.

  When the composition of the present invention is allowed to stand at room temperature (for example, 5 to 35 ° C.) for 3 days or more, a sufficient cured product with reduced surface tack can be obtained.

Applications The composition of the present invention can be used for various applications. In other words, it has a high fluorine content, so it has excellent solvent resistance and chemical resistance, low moisture permeability, and low surface energy, so it has excellent releasability and water repellency, thus requiring oil resistance. Rubber parts for automobiles, specifically automobile diaphragms, valves, seals, etc .; rubber parts for chemical plants, specifically pump diaphragms, valves, hoses, packings, oil seals, Sealing materials such as gaskets and tank pipe repair sealing materials; rubber parts for inkjet printers; rubber parts for semiconductor manufacturing lines, specifically sealing materials for diaphragms, valves, packings, gaskets, etc. for equipment that comes into contact with chemicals, etc. Valves that require low friction and wear resistance, etc. Rubber parts for analysis and physics and chemistry equipment, specifically diaphragms for pumps, valves, seal parts (packaging) Rubber parts for medical equipment, specifically pumps, valves, joints, etc .; tent film materials; sealants; molded parts; extruded parts; coating materials; copier roll materials; Useful for potting materials; sealing materials for fuel cells; sealing materials for machine tools; laminated rubber cloths.

  EXAMPLES Hereinafter, although an Example and a comparative example are shown and this invention is demonstrated concretely, this invention is not restrict | limited to the following Example. The number average molecular weight (or number average degree of polymerization) was determined by gel permeation chromatography (GPC) analysis using Asahi Clin AK-225 (Asahi Glass Co., Ltd., Hydrochlorofluorocarbon-225 (HCFC-225)) as a developing solvent. It is measured.

[Production Example 1]
Manufacture of base compound for room temperature curable composition 100 parts by mass of polymer (viscosity 7.8 Pa · s, number average molecular weight 15,700) represented by the following formula (2) and colloidal material whose surface is treated with fatty acid After mixing into a planetary mixer at a compounding ratio of 40 parts by mass of calcium carbonate (average particle size: 0.03 to 0.06 μm, product name Carlex 300: manufactured by Maruo Calcium Co., Ltd.), kneading is performed for 1 hour. It was. Subsequently, dispersion was promoted with a three-roll, and cooled to produce a base compound.

[Production Example 2]
Manufacture of crosslinker compound for room temperature curable composition 1
Fluorine-modified amino group-containing siloxane polymer represented by the following formula (3) (viscosity 1,000 Pa · s, number average molecular weight 16,000) 69.0 parts by mass and powdered molecular sieve 4A (average particle size 10 μm or less, MERCK) 3.4 parts by mass, calcium carbonate (average particle size 1.2 μm, product name Whiten SSB red: product made by Shiroishi Calcium Co., Ltd., trade name) 8.6 parts by mass as a filler after being put into a planetary mixer, The mixture was kneaded for 15 minutes and then mixed under reduced pressure (−65 to −75 cmHg) at room temperature for 30 minutes. Thereafter, 40.0 parts by mass of an oily fluoropolymer (one-end vinyldimethylsilyl group-blocked perfluoropolyether oil) represented by the following formula (4) as a viscosity modifier is added to the obtained compound, and the mixture is added to the planetary mixer. The mixture was kneaded for 15 minutes, and then mixed under reduced pressure (−65 to −75 cmHg) for 30 minutes at room temperature to produce a crosslinking agent compound.

[Production Example 3]
Manufacture of cross-linking compound for room temperature curable composition 2
Fluorine-modified amino group-containing siloxane polymer represented by the above formula (3) (viscosity 1,000 Pa · s, number average molecular weight 16,000) 69.0 parts by mass with calcium carbonate (product name Whiten SSB Red: Shiraishi Calcium Co., Ltd.) Product, trade name, ibid.) 12.0 parts by mass was charged into a planetary mixer, kneaded for 15 minutes, and then mixed under reduced pressure (-65 to -75 cmHg) at room temperature for 30 minutes. Thereafter, 40.0 parts by mass of an oily fluoropolymer represented by the above formula (4) is added as a viscosity modifier to the obtained compound, kneaded for 15 minutes with a planetary mixer, and then decompressed at room temperature for 30 minutes. Mixing (−65 to −75 cmHg) was performed to produce a crosslinker compound.

[Example]
121 parts by mass of the crosslinking agent compound produced in Production Example 2 (primary amino group / ethyl ester group = 3.0 (molar ratio)) with respect to 140 parts by mass of the base compound produced in Production Example 1 above. Are filled in polypropylene cartridges (mixpac system 50, 1: 1 cartridge) at this mixing ratio and stored at 30 ° C. and 90% RH for a long period (2 months, 5 months). Thereafter, the curability and the physical properties of the rubber after curing were evaluated.

[Comparative example]
In the above examples, the crosslinking agent compound was produced in Production Example 3 and changed to 121 parts by mass (amount of primary amino group / ethyl ester group = 3.0 (molar ratio)), otherwise A long-term storage stability test was conducted in the same manner as in the Examples.

Curability test The sample after long-term storage obtained from the above Examples and Comparative Examples was mixed and discharged by passing through a static mixer (6.3 mm × 17, manufactured by Mixpac), and this was received in a container for viscosity measurement. The curability was evaluated by following the viscosity change after 5 minutes from the start of mixing. Regarding the viscosity measurement, the measurement was performed according to JIS K7117-1. The results are shown in FIGS.

1 and 2, it can be seen that the curability is almost equal to the initial value even after long-term storage. On the other hand, in the comparative example, it is confirmed that the curability is delayed due to the increase in the moisture absorption amount according to the storage period.

Evaluation of physical properties after curing The curable compositions obtained from the above Examples and Comparative Examples were formed into a sheet having a thickness of 2 mm and allowed to stand at room temperature (23.5 ° C.) for 1 week to obtain a cured product. With this cured product sample, rubber physical properties were measured according to JIS K6251 and JIS K6253. The results are shown in FIGS.

In the explanatory examples of FIGS. 3 to 5, it can be seen that the physical properties of rubber after curing are almost the same as the initial state even after long-term storage. On the other hand, in the comparative example, a decrease in hardness and an increase in elongation at cutting are confirmed. Like the curability, this is thought to be due to the inhibition of curing due to moisture absorption during long-term storage, resulting in a decrease in physical properties.

Claims (4)

(A) Number average molecular weight of 3,000 to 100 represented by the following general formula (1) having at least two ester groups in one molecule and having a divalent perfluoroalkyl ether structure in the main chain , 1,000 linear fluoropolyether compound: 100 parts by mass,
ROOC-Rf-COOR '(1)
(In the formula, Rf is a divalent perfluoroalkyl ether structure selected from the following formulas (i) to (iii), and R and R ′ are the same or different 1 to 8 substituted or unsubstituted 1 to 8 carbon atoms. Valent hydrocarbon group.)

(In the formula, p and q are integers of 1 to 150, and the sum of p and q is 2 to 200. Also, r is an integer of 0 to 6, and t is 2 or 3.)

(In the formula, u is an integer of 1 to 200, v is an integer of 1 to 50, and t is the same as above.)

(In the formula, x is an integer of 1 to 200, y is an integer of 1 to 50, and t is the same as above.)
(B) Siloxane polymer containing at least three amino groups in one molecule: (b) Total amount of amino groups in component / (a) Total amount of ester groups in component = 1.0 to 5.0 ( Molar ratio) and (c) molecular sieve having an average particle size of 30 μm or less: (b) 1 to 20 parts by mass per 100 parts by mass of component Ether-based rubber composition.   2. The room temperature curable fluoropolyether rubber composition according to claim 1, which is a two-component type comprising a base compound mainly composed of component (a) and a crosslinker compound composed mainly of components (b) and (c). object. The room temperature curable fluoropolyether rubber composition according to claim 1 or 2, wherein the component (b) is selected from amino group-containing siloxane polymers represented by the following formulas (iv) to (vii).

(In the formula, n is an integer of 3 to 50.)

(In the formula, n is an integer of 3 to 50.)

(In the formula, a is 3 to 50, b is 1 to 50, a + b = 4 to 100, and c is an integer satisfying 0 to 100.)

(Wherein, a is 3 to 50, b is 1 to 50, a + b = 4 to 100, and n is an integer satisfying 1 to 10) A cured product obtained by curing the room temperature-curable fluoropolyether rubber composition according to any one of claims 1 to 3 .

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