JP2005239835A - Crosslinkable fluororubber composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a crosslinkable fluororubber composition, more specifically, capable of forming by vulcanization molding such a crosslinked fluororubber molded form as to be high in mechanical strength, low in coefficient of surface friction and abrasion resistance and therefore suitably usable as a sealant or the like in terms of hardness, modulus, compression set, etc. <P>SOLUTION: The crosslinkable fluororubber composition comprises (i) 100 pts.wt. of a crosslinkable fluororubber, (ii) 1-20 pt(s).wt. of a layered compound organization-treated with a quaternary ammonium salt, (iii) 0.3-3 pt(s).wt. of a crosslinking agent and (iv) 4-8 pts.wt. of a cocrosslinking agent. Preferably, this composition also contain (v) 0.1-30 pt(s).wt., based on 100 pts.wt. of the crosslinkable fluororubber, of a filler. A sealant produced by crosslinking(vulcanization) molding of this composition is also provided. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a crosslinkable fluororubber composition. More specifically, by vulcanization molding, the present invention has high strength, low surface friction coefficient, low wear, hardness, modulus, compression set, etc. The present invention relates to a cross-linkable fluororubber composition capable of forming a cross-linked fluororubber molded article that can be suitably used as a sealing material or the like.

  Rubber moldings are widely used as sealing materials for chemical equipment, semiconductor manufacturing equipment, chemical piping / tanks, food manufacturing equipment, and the like. However, since a rubber molded body generally has a high coefficient of friction and high tackiness, the inherent characteristics of the rubber material are not utilized and the range of use thereof may be limited.

  Among such rubber molded products, those made of fluororubber are excellent in plasma resistance, heat resistance, and chemical resistance, and are used as sealing materials for semiconductor manufacturing equipment taking advantage of these features. However, the generation of particles due to wear with the mating material becomes a problem, and there is a problem that it is not always sufficient in terms of opening / closing workability of the opening / closing part for use as an opening / closing part sealing material of a semiconductor manufacturing apparatus. is there.

In order to solve such problems, the rubber base surface has low friction, non-adhesiveness, and wear resistance while maintaining the inherent compression set, rubber elasticity, mechanical strength, and deformation followability of the rubber material. In order to obtain a rubber material having plasma resistance, various surface treatment methods have been proposed (for example, JP-A-2
002-371151 (Patent Document 1), JP-A-11-172027 (Patent Document 2), JP-A-11-199691 (Patent Document 3), JP 7-103258 (Patent Document 4)) .

  However, in the rubber surface modification methods described in these publications, even if a certain degree of goodness can be obtained in any one of non-adhesiveness, low friction coefficient, low wear, low outgassing property, etc., Fluoro-rubber molded product (high-strength, low surface friction coefficient, low wear, excellent balance in terms of hardness, modulus, compression set, etc.) A crosslinkable fluororubber composition capable of forming a (sulfur) has not been obtained.

  Therefore, as a result of intensive studies to solve the above problems, the present inventors, when using acrylonitrile-butadiene copolymer rubber, may contain a layered compound subjected to a specific treatment. The resulting sealing material can only achieve the effect of the filler addition effect, but the peroxide vulcanized crosslinkable fluororubber (and those containing a crosslinking agent and a co-crosslinking agent) are subjected to a specific treatment. In the present invention, it is found that if the cross-linkable fluororubber composition is vulcanized (crosslinked), the mechanical strength can be improved and the friction coefficient can be significantly reduced. It came to complete.

  In addition, (a) JP 2000-178422 A (Patent Document 5) describes an inorganic layered compound and polybutylene terephthalate (PBT), polycarbonate, polyethylene terephthalate, phenol resin, phenoxy resin, fibrous reinforcing material, fluorine-based resin. In addition, a flame-retardant polybutylene terephthalate resin composition for electrical product terminal members containing carbon black and the like is disclosed, and is described as being excellent in flame retardancy, low warpage, heat resistance, self-tapping properties, and the like.

In addition, examples of the inorganic layered compound include kaolinite, talc, smectite, mica, and the like, and an organic treatment for exchanging inorganic ions between layers with organic ions may be performed, and 0 to 30 weights with respect to 100 parts by weight of PBT. It is also described that it is added in parts.

  (B) Japanese Unexamined Patent Publication No. 2000-226585 (Patent Document 6) discloses a flame retardant containing an inorganic layered compound and a flame retardant molded article containing the same. From the viewpoint of flame retardancy, an inorganic layered compound is disclosed. It is also described that it is contained in an amount of 1% by weight or more.

  Further, it is described that the flame retardant may contain a resin having a relatively slow combustion rate such as a polyolefin resin.

  (C) Japanese Patent Application Laid-Open No. 7-82398 (Patent Document 7) discloses an antifogging agent composition containing a mixed colloid solution, an anionic surfactant, an organic electrolyte, an inorganic layered compound, and the like, and dispersing it in a dispersant. An anti-fogging agent that has been applied to the surface of a thermoplastic resin film and then dried is disclosed.

  (D) Japanese Patent Laid-Open No. 7-205376 (Patent Document 8) includes a layer composed of a resin composition containing an inorganic layered compound having a particle size of 5 μm or less and an aspect ratio of 50 to 5000, and a resin, and a heat seal layer. A gas barrier packaging bag having the following is disclosed.

  (E) JP-A-8-302025 (Patent Document 9) describes an elastomer in which an organic cation is brought into contact with a layered compound and then swollen with an organic solvent. And a method for producing an inorganic filler-containing elastomer having high rigidity, heat resistance, and impact resistance, and a composite resin material excellent in impact resistance are disclosed. The fine inorganic filler is contained in the elastomer at a high concentration. It is described that it can be contained. Examples of the elastomer include ethylene propylene copolymer (EPR), EBR, EPDM, SBR, BR, POR, SEBS and the like.

  However, in the composite resin material described in Patent Document 9 or a manufacturing method thereof, a general (vulcanized) non-fluorinated rubber or the like is used together with the layer compound, and such a composite resin material is used. However, an elastic sealing material having high strength, a low surface friction coefficient, and excellent balance in hardness, 100% tensile stress (modulus), compression set, etc. cannot be obtained.

  (F) Japanese Patent Application Laid-Open No. 11-263876 (Patent Document 10) discloses an organic-inorganic composite (filler) in which an organic compound or a polymer thereof is intercalated between layers of a layered compound, and the composite A hybrid material in which (filler) is finely dispersed in a polymer matrix is disclosed, the mutual force between the polymer matrix and the composite is strong, has sufficient mechanical properties, and is useful for molding materials, films, etc. It is described.

  (G) JP-A-11-293033 (Patent Document 11) describes an organic-inorganic composite obtained by adding a solvent to the organic-inorganic composite (filler) described in JP-A-11-263876 (Patent Document 10). A body composition and a hybrid material in which the composition is finely dispersed in a polymer matrix are disclosed, and are described as having the same effect as Patent Document 10 above.

However, among these Patent Documents 5 to 11, except for Patent Document 9, all attempts are made to improve the physical properties of the resin compound by blending the layered compound into the resin, and improve the physical properties of the rubber. It is not intended.
JP 2002-371151 A Japanese Patent Laid-Open No. 11-172027 Japanese Patent Laid-Open No. 11-199691 Japanese Examined Patent Publication No. 7-103258 JP 2000-178422 A JP 2000-226585 A JP-A-7-82398 JP-A-7-205376 JP-A-8-302025 JP-A-11-263876 Japanese Patent Laid-Open No. 11-293033

  The present invention is to solve the problems associated with the prior art as described above. By vulcanization molding, the present invention has high strength, low surface friction coefficient, low wear, and hardness. Another object of the present invention is to provide a crosslinkable fluororubber composition capable of forming a cross-linked fluororubber molded article that can be suitably used as a sealing material in terms of modulus, compression set, and the like.

The crosslinkable fluororubber composition according to the present invention comprises:
(I) a crosslinkable fluororubber;
For 100 parts by weight of the crosslinkable fluororubber,
(Ii) 1 to 20 parts by weight of a layered compound organically treated with a quaternary ammonium salt;
(Iii) 0.3 to 3 parts by weight of a crosslinking agent (vulcanizing agent);
(Iv) 4 to 8 parts by weight of a co-crosslinking agent is included.

  In the present invention, it is preferable to further include (v) a filler in an amount of 0.1 to 30 parts by weight with respect to 100 parts by weight of the crosslinkable fluororubber.

  The sealing material according to the present invention is obtained by crosslinking (vulcanizing) molding the crosslinkable fluororubber composition described above.

The method for producing the crosslinkable fluororubber composition according to the present invention includes:
(I) a crosslinkable fluororubber;
(Ii) a layered compound previously organically treated with a quaternary ammonium salt;
(Iii) a crosslinking agent;
(Iv) The co-crosslinking agent is added and mixed at once or in any order.

  The method for producing a crosslinked fluororubber molded product according to the present invention is characterized in that the crosslinkable fluororubber composition described above is heated in a mold and crosslinked to be molded into a desired shape.

  According to the present invention, by vulcanization (crosslinking) molding, it has high strength, low surface friction coefficient, low wear, and is suitable as a sealing material in terms of hardness, modulus, compression set, etc. There is provided a crosslinkable fluororubber composition capable of forming a cross-linked fluororubber molded product that can be used in the present invention.

Hereinafter, the crosslinkable fluororubber composition according to the present invention will be described more specifically.

[Crosslinkable fluororubber composition]
The crosslinkable fluororubber composition (unvulcanized product) according to the present invention includes (i) a crosslinkable fluororubber, (ii) a layered compound treated with a quaternary ammonium salt, and (iii) A crosslinking agent and (iv) a co-crosslinking agent are included.
<Crosslinkable fluororubber (i)>
The crosslinkable fluororubber (i) is also referred to as an unvulcanized fluororubber, and examples of the crosslinkable type include peroxide vulcanization, polyol vulcanization, amine vulcanization, electron beam crosslinking, and the like. For example, perfluoro-crosslinkable fluororubber (FFKM) that is fully fluorinated (100%) bonded to the main chain carbon atom, or a carbon-hydrogen bond exists in a part of the main chain carbon atom. Ordinary cross-linkable fluororubber (FKM, hydrogen atom fluorination rate: for example, 60% to less than 100%) is used.

  In the present invention, among these crosslinkable fluororubbers, those capable of peroxide vulcanization (crosslinking) are preferably used because various physical properties can be imparted by using a relatively small amount of filler.

  The fluoroplastic elastomer that can be extruded or the like is usually recognized as non-crosslinkable (although a special crosslinking method called radiation crosslinking is adopted) and excluded from the object of the present invention. .

  In the present invention, these crosslinkable fluororubbers may be used alone or in combination of two or more.

Among the crosslinkable fluororubbers (i), as a typical crosslinkable fluororubber (FKM) having a carbon-hydrogen bond in a part of main chain carbon atoms, specifically, for example, vinylidene fluoride (VDF) ) / Binary crosslinkable fluororubber such as hexafluoropropylene (HFP);
Examples thereof include ternary cross-linkable fluororubber such as vinylidene fluoride (VDF) / hexafluoropropylene (HFP) / tetrafluoroethylene (TFE).

As such a cross-linkable fluororubber, “Daiel G902” (manufactured by Daikin Industries, Ltd., peroxide cross-linkable fluororubber, VDF / HFP / TFE terpolymer) Etc.
<Layered Compound Treated with Quaternary Ammonium Salt (ii)>
The layered compound (ii) treated with the quaternary ammonium salt (organization treatment) is in the crosslinkable fluororubber composition of the present invention, and the action of this quaternary ammonium salt, presumably by the catalytic action, The defluorination reaction of the crosslinkable fluororubber (i) occurs, and as a result, a new crosslink site is generated in the main chain of the crosslinkable fluororubber (i), and this crosslink site reacts with an unreacted co-crosslinking agent. Thus, it is considered that the crosslink density of the fluororubber is improved and a high strength crosslinkable fluororubber can be formed.

  Further, in the cross-linked fluororubber molded article, it is considered that the surface friction coefficient is reduced by the orientation of the layered compound contained therein, thereby contributing to improvement in wear resistance.

  As a method for preparing the layered compound (ii) treated with a quaternary ammonium salt or the layered compound (ii), a conventionally known method or a preparation method can be appropriately employed. The method and method described in columns [0014] to [0021] of JP-A-8-302025 (Patent Document 9), the method described in column [0036] of JP-A-2000-178422 (Patent Document 5), and Methods, methods and methods described in columns [0005] to [0013] of JP-A-2000-226585 (Patent Document 6), and [0016] to [0019] of JP-A-7-82398 (Patent Document 7). The method described in the column may be applied.

  In order to prepare a layered compound (ii) treated with a quaternary ammonium salt, for example, first, water and a hydrophilic layered compound (a layered compound excellent in swelling property or cleavage property in water) Example: hydrophilic mica etc.).

  Next, a quaternary ammonium salt as an organic treatment agent for the layered compound is added to the mixed solution, and the mixture is stirred and mixed.

Thus, when a layered compound and a quaternary ammonium salt are brought into contact with each other and reacted, for example, by adding / mixing a quaternary ammonium salt to the mixed solution of the layered compound, for example, hydrophilic mica exists between the layers. Sodium ion (Na ⁺ ) is a cation of a quaternary ammonium salt (a quaternary ammonium ion, for example, [N (R ¹ ) (R ² ) (R ³ ) (R ⁴ ) in the following formula (a)) )] The cation represented by ⁺¹ ) is replaced, and it is considered that ion exchange is performed.

  The layered compound (ii) that has been organically treated (ion exchange treatment) with a quaternary ammonium salt, which is a product of such a reaction, does not cleave and disperse in the presence of water, but becomes a precipitate.

The reaction mixture is then filtered and the resulting filtrate is washed, for example, with water,
Quaternary ammonium ions are intercalated (ion exchange)
The layered compound (ii) thus obtained is obtained.

  In the present invention, the filtrate obtained as described above is once dried and then, if necessary, pulverized using a ball mill or the like to obtain a desired particle size treated with a quaternary ammonium salt. A layered compound (ii) may be obtained and used for the production of a crosslinkable fluororubber composition or a cross-linked fluororubber molded article.

  Examples of the quaternary ammonium salt include quaternary ammonium salts such as those described in columns [0015] to [0018] of JP-A-8-302025, preferably a trialkylammonium salt (1). Is used.

  That is, the general formula (a):

[In the formula (a), R ¹ , R ² , R ³ and R ⁴ each independently represents an alkyl group which may have a branch having about 1 to 20 carbon atoms, and the main chain carbon of R ⁴ The number is the same as or larger than the carbon number of the main chain of R ¹ , R ² , and R ³ , and is preferably about 4 to 15 carbon atoms. X represents an anion of an acid constituting the salt, for example, (halogen ions such as Cl ⁻ , NO ₃ ⁻ , SO ₄ ²⁻ ) and the like, preferably Cl ⁻ and OH ⁻ . m represents the valence of the anion, and is preferably 1, 2 and especially 1. ]
The thing represented by is mentioned.

  More specifically, for example,

[In Formula (a-1), n is an integer of about 1 to 20. X represents, for example, OH ⁻ , Cl ⁻ , NO ₃ ⁻ , SO ₄ ^2−, etc., preferably OH ⁻ . m represents the valence of the anion (X), preferably 1. ],
Examples include alkylamines having about 3 to 25 carbon atoms, preferably about 8 to 16 carbon atoms, such as hexylamine, dodecylamine, and octadecylamine. Among them, dodecylamine is most commonly used. These quaternary ammonium salts may be used alone or in combination of two or more.

  The layered compound (untreated product) subjected to the treatment with the quaternary ammonium salt may be either a natural product or a synthetic product, and is not particularly limited. For example, in the above-mentioned JP-A-8-302025 [0014] Swellable clay minerals as described in the column, specifically (natural or synthetic mica, natural or synthetic smectite, kaolinite, talc, etc., among them, synthetic mica, synthetic smectite, natural montmorillonite The average particle size (D50) of these layered compounds is usually about 0.05 to 100 μm, preferably about 0.05 to 2 μm. You may use a compound 1 type or in combination of 2 or more types.

In addition, as a layered compound (ii) treated with such a quaternary ammonium salt, a commercially available “Somasif MEE” {manufactured by Co-op Chemical Co., Ltd., average particle diameter (D50) 1 μm, untreated layered form Layered silicate formed by treating sodium ion in compound with quaternary ammonium salt}, “Smectite SAN” {manufactured by Co-op Chemical Co., Ltd., average particle size (D50) 50 μm, sodium ion in untreated layered compound Synthetic smectite obtained by treatment with a quaternary ammonium salt},
“Smectite STN” (manufactured by Co-op Chemical Co., Ltd., average particle diameter (D50) 50 μm, sodium ion in untreated layered compound treated with quaternary ammonium salt), and the like.
<Crosslinking agent (iii)>
As the crosslinking agent (vulcanizing agent) (iii), a peroxide-based crosslinking agent (peroxide-based crosslinking agent) is used.

As such a peroxide-based crosslinking agent, conventionally known ones can be widely used. Specifically, for example,
2,5-dimethyl-2,5-di (t-butylperoxy) hexane (“Perhexa 25B” manufactured by NOF Corporation), dicumyl peroxide (“PARK Mill D” manufactured by NOF Corporation), 2,4-dichlorobenzoyl peroxide , Di-t-butyl peroxide, t-butyl dicumyl peroxide, benzoyl peroxide (manufactured by NOF Corporation, “NIPER B”), 2,5-dimethyl-2,5- (t-butylperoxy) hexyne-3 ( "Perhexine 25"
B "), 2,5-dimethyl-2,5-di (benzoylperoxy) hexane, α, α'-
Examples thereof include bis (t-butylperoxy-m-isopropyl) benzene (manufactured by NOF Corporation, “Perbutyl P”), t-butylperoxyisopropyl carbonate, parachlorobenzoyl peroxide, t-butyl perbenzoate, and the like.

Of these, dicumyl peroxide, 2,4-dichlorobenzoyl peroxide, benzoyl peroxide, and α, α′-bis (t-butylperoxy-m-isopropyl) benzene are preferred.

  These crosslinking agents may be used alone or in combination of two or more.

  In the present invention, as the fluororubber (i), a peroxide vulcanized unvulcanized fluororubber preferably containing bromine (Br), iodine (I) or the like as a cure site is used. In this peroxide vulcanized rubber, the crosslinking agent (iii), preferably bromine (Br), iodine (I), etc. of the unvulcanized rubber is removed by the peroxide crosslinking agent, and an active site is generated at the site, C—C bond in which the cross-linking point is chemically stable by cross-linking (bonding) with a co-crosslinking agent (iv) (for example, “TAIC”) so as to connect these active sites generated at different sites. Crosslinks with excellent balance in terms of chemical resistance and mechanical properties compared to C = N bond when polyamine vulcanization and C—O bond when polyol vulcanization A fluororubber molded product is obtained. Considered.

Incidentally, in polyol vulcanization, for example, VDF-HFE unvulcanized rubber [—CF ₂ CF (CF ₃ ) CH ₂ CF ₂ CH ₂ —] and acid acceptors “Ca (OH) ₂ , MgO”, etc. And an vulcanization accelerator “NR ₄ ⁺ X ⁻ , R: an anion such as an alkyl group, X: Cl” and the like, and an unsaturated bond site [—CF ₂ CF (CF ₃ ) CH═CFCH ₂ —] , And vulcanizing agent bisphenols (HO
R′OH, R ′: a divalent organic group), for example, different C═C bonding sites by crosslinking with bisphenol A [HO—Ph—C (CF ₃ ) ₂ —Ph—OH, Ph: phenylene group]. As described above, a “—O—R′—O—” bond having a crosslinked structure is formed.

  This polyol cross-linked product has good scorch resistance, good processability and low compression set, but the peroxide vulcanized fluoro rubber is better balanced in terms of chemical resistance and mechanical properties. An excellent crosslinked fluororubber molded product is obtained.

In addition, when the thing diluted with diluents, such as a silica gel, is used as the said crosslinking agent (example: brand name "Perhexa 25B-40" made by Nippon Oil & Fats Co., Ltd.), according to the dilution rate, crosslinkable fluorine What is necessary is just to adjust suitably the addition amount of a compound containing a crosslinking agent so that the amount of crosslinking agents in a rubber composition may become a desired range. However, since silica gel or the like may cause generation of particles, it is desirable to refrain from using it as much as possible.
<Co-crosslinking agent (iv)>
Specific examples of the co-crosslinking agent (vulcanization aid) (iv) include triallyl isocyanurate (manufactured by Nippon Kasei Co., Ltd., “TAIC”), triallyl cyanurate, triallyl formal, triallyl trimelli. Examples thereof include compounds capable of co-crosslinking with radicals such as tate, N, N′-m-phenylenebismaleimide, dipropargyl terephthalate, diallyl phthalate, and tetraallyl terephthalamide.

  Of these, triallyl isocyanurate is preferable in terms of heat resistance and reactivity.

In the crosslinkable fluororubber composition according to the present invention, (ii) “a layered compound treated (organized) with a quaternary ammonium salt” with respect to (i) 100 parts by weight of the crosslinkable fluororubber. Is usually 1-20 parts by weight, preferably 3-10 parts by weight,
(Iii) The crosslinking agent is usually 0.3 to 3 parts by weight, preferably 0.5 to 1.5 parts by weight,
(Iv) The co-crosslinking agent is usually contained in an amount of 4 to 8 parts by weight, preferably 4 to 6 parts by weight.

  When the amount of (ii) “layered compound treated with quaternary ammonium salt” in the crosslinkable fluororubber composition is less than the above range, the cross-linked fluororubber molded article has a large mechanical strength improvement. However, if the amount is larger than the above range, the hardness becomes very high due to an excessive crosslinking reaction, and it tends to be difficult to attach to various places of use.

  Further, (iii) when the blending amount of the crosslinking agent is less than the above range, the crosslinking does not proceed sufficiently and molding tends to be difficult, and (iii) when the blending amount of the crosslinking agent is greater than the above range, heating, etc. In the cross-linking reaction, the contained co-crosslinking agent (iv) is consumed by the cross-linking agent, so that the effect of the cross-linking treatment cannot be obtained and the physical properties necessary for the sealing material cannot be obtained. is there.

Further, (iv) when the amount of the co-crosslinking agent is less than the above range, the content of the unreacted co-crosslinking agent that reacts with the crosslinking reaction active site formed by the quaternary ammonium salt becomes insufficient, and the organically treated layered state There is a tendency that the addition effect of the compound cannot be obtained, and if it exceeds the above range, the crosslinking density becomes too high, adversely affecting physical properties such as elongation of the rubber molded body, and cracking may occur at high temperature and compression. is there.
<Filler (v)>
When the crosslinkable fluororubber composition of the present invention further contains (v) a filler, the (v) filler is preferably 0.1 to 30 parts by weight, preferably 100 parts by weight of the crosslinkable fluororubber. Is preferably contained in an amount of 0.1 to 20 parts by weight from the viewpoint of improving the physical properties required when using the obtained vulcanized rubber molded article as a sealing material, such as hardness, compression set, and the like.

Examples of the filler include carbon black, titanium oxide, and silica gel.
<Other ingredients>
The crosslinkable fluororubber composition according to the present invention comprises the above components (i), (ii), (iii), (
iv) and optionally component (v), but if necessary, may further contain (solvent, plasticizer, etc.) in an appropriate amount.

[Method for producing crosslinkable fluororubber composition]
The method for producing a crosslinkable fluororubber composition according to the present invention comprises the above amounts of the crosslinkable fluororubber (i), “a layered compound treated with a quaternary ammonium salt” (ii), and a crosslinking agent. (Iii) and the co-crosslinking agent (iv) may be added at once or in any order and mixed, that is, stirred, kneaded, or the like.

  In this mixing, if necessary, kneading may be performed using a commercially available Banbury, open roll, kneader, biaxial kneader or the like. Moreover, you may perform heating (example: 80-120 degreeC) etc. at the temperature which the vulcanization (crosslinking) of the said crosslinkable fluororubber does not advance rapidly as needed.

  In the present invention, as the layered compound to be added in the production of the crosslinkable fluororubber composition, it is possible to add a compound that has been organically treated with a quaternary ammonium salt in advance. Necessary in terms of ease.

Here, instead of the above (ii) “a layered compound treated with a quaternary ammonium salt”, “a layered compound not treated with a quaternary ammonium salt and a quaternary ammonium salt” Are mixed with (i) a crosslinkable fluororubber, (iii) a crosslinker, (iv) a cocrosslinker, etc., which are components constituting the crosslinkable fluororubber composition at the same time or at different times. In view of the fact that the kneadability is very inferior and there is a concern about the blooming and decomposition of the ammonium salt, it is desirable to use a layered compound that has been subjected to organic treatment in advance.

[Fluoro rubber molded product (especially sealing material)]
The cross-linked fluororubber molded product according to the present invention is formed by heating the crosslinkable fluororubber composition described in any of the above to a desired shape by heating (crosslinking) in a mold.

  Crosslinking (vulcanization) may be carried out by a conventional method. For example, the crosslinkable fluororubber composition (compound) is molded into a desired shape (preliminary molding, primary molding) and then secondary vulcanized. Can be implemented.

  When molding into a desired shape (preliminary molding or primary molding), the heating temperature is usually 150 to 180 ° C. As for the above conditions (temperature, etc.), the temperature may be raised continuously or stepwise, then kept at a constant temperature or the like for a predetermined time, and then the temperature may be lowered.

  The pressurizing conditions and temperature rising conditions during molding vary greatly depending on the shape and dimensions of the molded body and are not generally determined. For example, after gradually raising the temperature from 120 ° C to 170 ° C, the temperature is increased to 170 ° C. It is possible to maintain the temperature for 10 minutes and then lower the temperature to room temperature, but usually, from the viewpoint of energy efficiency, the temperature is further raised and secondary vulcanization is performed.

  “Secondary vulcanization” is performed, for example, by holding at a heating temperature of 180 to 230 ° C. for 1 to 24 hours. The vulcanization molding may be performed under normal pressure or under pressure.

The cross-linked fluororubber molded article as the sealing material thus obtained is similar to the sealing material described in the [0019] to [0020] columns of Japanese Patent Publication No. 2003-342552 by the following method. When the physical properties are measured and evaluated, the following characteristics are exhibited.
(Hardness) When measured by a durometer type A hardness test at 25 ° C. in accordance with JIS-K6253, the hardness is 60 to 90, which indicates physical properties suitable as a sealing material.
(Tensile strength) When measured at 25 ° C. in accordance with JIS-K6251, it is 9.8 MPa or more, indicating physical properties suitable as a sealing material.
(Elongation) When measured at 25 ° C. in accordance with JIS-K6251, it is 150% or more.
Physical properties suitable as a sealing material.
(Compression set) According to JIS-K6262, when the compression set is measured using a φ29 × 12.5 disk under the conditions of 200 ° C. × 70 hours and compression rate of 25%, it is 25% or less. It exhibits physical properties suitable as a sealing material.

  Further, the “100% tensile stress (modulus)” of the crosslinked fluororubber molded article as the sealing material was measured as follows.

(100% tensile stress (modulus)) Based on JIS K-6256, when the stress at the time when the marked line has a width of 40 mm is measured, it is 2.5 to 15 MPa, indicating physical properties suitable as a sealing material.
[Example]
Hereinafter, the cross-linkable fluororubber composition according to the present invention and a cross-linked fluororubber molded product typified by a sealing material obtained by vulcanizing (cross-linking) the composition will be described in more detail with reference to examples. However, the present invention is not limited to the embodiment.

The conditions for measuring normal physical properties used in the following examples and comparative examples are as follows.
(Hardness)
Based on JIS-K6253, it measured by the durometer type A hardness test at 25 degreeC. As a result, those having a hardness of 60 to 90 were determined to be physical properties suitable as a sealing material.
(Tensile strength)
It measured at 25 degreeC based on JIS-K6251. As a result, it was judged that the material having a pressure of 9.8 MPa or more was a physical property suitable as a sealing material.
(Elongation)
It measured at 25 degreeC based on JIS-K6251. As a result, it was judged that the material having 150% or more is a physical property suitable as a sealing material.
(Compression set)
In accordance with JIS-K6262, the compression set was measured using a φ29 × 12.5 disk under the conditions of 200 ° C. × 70 hours and a compression rate of 25%. As a result, it was judged that those having a ratio of 50% or less were suitable physical properties as a sealing material.
(100% tensile stress (modulus))
Based on JIS K-6256, the stress when the marked line became 40 mm in width was measured. As a result, a material having a pressure of 2.5 to 15 MPa was determined to be a physical property suitable as a sealing material.
(Abrasion coefficient, friction coefficient)
The wear coefficient and friction coefficient were measured using a thrust type friction and wear tester (manufactured by Mitsui Engineering & Shipbuilding, TT100C type).

The measurement conditions are as follows.
(Surface pressure: 2 kgf / cm ² , Speed: 0.1 m / sec, Sliding time: 13.889 h
rs, counterpart material: SS400 (Ra = 0.3), temperature: R.I. T (room temperature), atmosphere: Air)
Moreover, the compounding components used in the following Examples and Comparative Examples are as follows.
(1) Crosslinkable fluororubber (a) “DAIEL G902”, manufactured by Daikin Industries, Ltd.
Component composition: copolymerized vinylidene fluoride, tetrafluoroethylene and hexafluoropropylene, peroxide-crosslinking type ternary crosslinkable fluororubber, fluorine content: 71 mass%, Mooney viscosity ML _{1 + 10} ( 100 ° C.): 50.
(B) "TECNOFLON P959", a copolymer of vinylidene fluoride, tetrafluoroethylene, and hexafluoropropylene, a peroxide-crosslinking type ternary crosslinkable fluororubber, manufactured by Solvay, fluorine content: 70% by weight, Mooney viscosity ML _{1 + 10} (121 ° C.): 51.
(2) Acrylic nitrile-butadiene copolymer rubber “Nipol 1043”, manufactured by Nippon Zeon Co., Ltd., acrylonitrile content: 25% to less than 31% (central value 29.0%), specific gravity: 0.97, Mooney Viscosity (central value): 77.5.
(3) Hydrophilic mica (a) Product name “Somasifu MAE”, manufactured by Co-op Chemical.
(B) “Somasif MEE”, manufactured by Corp Chemical.
(C) “Smectite SAN” manufactured by Co-op Chemical.
(D) “Smectite STN”, manufactured by Corp Chemical.
(4) Peroxide crosslinking agent (a) “Perhexa 25B”, manufactured by NOF Corporation, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane.
(5) Co-crosslinking agent (a) “TAIC”, manufactured by Nippon Kasei Co., Ltd., triallyl isocyanurate.
(6) Filler (a) “Thermo Black MT”, manufactured by (CANCARB).
(7) Others (a) “Noxeller TT-P”, tetramethylthiuram disulfide, manufactured by Ouchi Shinsei Chemical Co., Ltd., a thiuram vulcanization accelerator.
(B) “Noxeller CZ-G”, N-cyclohexyl-2-benzothiazolylsulfenamide, sulfenamide-based vulcanization accelerator, manufactured by Ouchi Shinsei Chemical Industry Co., Ltd.
[Example 1A]
A crosslinkable fluororubber composition having the following component composition was prepared.
<Composition composition of crosslinkable fluororubber composition>
Crosslinkable fluororubber {"DAIEL G902", manufactured by Daikin Industries, Ltd.} 100 parts by weight,
“Somasif MEE” (manufactured by Coop Chemical Co., Ltd.) 5 parts by weight
"TAIC" (manufactured by Nippon Kasei Co., Ltd.) as a co-crosslinking agent: 6 parts by weight
Peroxide crosslinking agent “Perhexa 25B” (manufactured by NOF Corporation): 0.5 part by weight.
(Total 111.5 parts by weight)

  Such a crosslinkable fluororubber compound was kept in a mold at a temperature of 165 ° C. for 15 minutes and subjected to primary vulcanization.

  Next, this primary vulcanizate was heat-treated at a temperature of 180 ° C. under atmospheric pressure for 24 hours.

Three pieces of No. 3 dumbbells were punched from the heat-treated product, and normal properties were measured under the above conditions.

As a result, the “hardness” (according to JIS-K6253, durometer type A hardness test at 25 ° C.) is 80,
“Tensile strength” (based on JIS-K6251 and measured at 25 ° C.) is 31.3 MPa,
“Elongation” (based on JIS-K6251 and measured at 25 ° C.) is 365%, and “compression set” (based on JIS-K6262, 200 ° C. × 70 hours, compression rate 25%) is 45%. And
“100% tensile stress (modulus)” (based on JIS K-6256) was 7.8 MPa.

The results are also shown in Table 1.
[Examples 2A to 3A, Comparative Examples 1A to 3A]
A sealing material was prepared in the same manner as in Example 1A except that the blending composition of the crosslinkable fluororubber composition was changed as shown in Table 1 in Example 1A, and the same physical properties as described above were measured.

  The results are summarized in Table 1.

  When comparing Comparative Example 1A in Table 1 with 2A, Comparative Example 1A does not contain hydrophilic mica that has not been treated with a quaternary ammonium salt (untreated mica). It differs in that it includes. As compared with Comparative Example 1A, it can be seen that in Comparative Example 2A containing untreated mica, the hardness, tensile strength, and 100% modulus are high, and the elongation is significantly reduced.

  Next, Comparative Examples 1A and 2A are compared with Examples 1A to 3A of the present application.

When comparing Comparative Example 2A containing 10 parts by weight of untreated mica and Examples 1A to 3A of the present application containing 5 parts by weight of various layered compounds treated with quaternary ammonium salts, the hardness of the present Example increases. It can be seen that the tensile strength, elongation, and 100% modulus are remarkably high.
[Examples 1B to 4B, Comparative Examples 1B to 2B]
A sealing material was prepared in the same manner as in Example 1A except that the blending composition of the crosslinkable fluororubber composition was changed as shown in Table 2 in Example 1A, and the same physical properties as described above were measured.

  The results are summarized in Table 2.

When comparing Comparative Example 1B of Table 2 and Example 1B, Comparative Example 1B does not contain a layered compound that has not been treated with a quaternary ammonium salt, and Example 1B contains 5 parts by weight. Is very different. Compared to Comparative Example 1B, in Example 1B, the hardness, tensile strength, and elongation of the normal physical properties are substantially the same with little change, but the 100% modulus is high and the wear coefficient is 10 times ( It can be seen that it has been reduced (improved) by one digit.
[Comparative Examples 1C to 3C]
A sealing material was prepared in the same manner as in Example 1A except that the blending composition of the crosslinkable fluororubber composition was changed as shown in Table 3 in Example 1A, and the same physical properties as described above were measured.

  The results are summarized in Table 3.

  Comparing Comparative Example 1C and 3C in Table 3, Comparative Example 1C does not contain a layered compound treated with a quaternary ammonium salt, and Comparative Example 3C only contains 10 parts by weight. Is different. Compared to Comparative Example 1C, in Comparative Example 3C containing a layered compound treated with a quaternary ammonium salt, hardness, tensile strength, and 100% modulus are almost the same among normal properties, but elongation is It turns out that it has fallen.

  Next, Comparative Example 3C is compared with Comparative Example 2C.

  First, Comparative Example 3C contains 95 parts by weight of carbon, whereas Comparative Example 2C is different only in that it does not contain carbon.

  Compared to Comparative Example 2C, it can be seen that Comparative Example 3C has higher hardness and significantly higher tensile strength and 100% modulus, but the elongation is decreased.

In short, Comparative Example 1C shown in Table 3 using an acrylonitrile-butadiene copolymer rubber in place of the peroxide vulcanizable cross-linkable fluororubber (i) as in Examples of the present application shown in Tables 1 and 2 In ~ 3C, even when the layered compound (ii) treated with the quaternary ammonium salt is blended, only the effect of the filler addition effect is obtained,
As in the present invention, in the sealing material using the peroxide vulcanizable crosslinkable fluororubber (i), when the layered compound (ii) treated with the quaternary ammonium salt is blended, Effects such as a significant reduction in the coefficient of friction are observed.

Claims (3)

(I) a crosslinkable fluororubber;
For 100 parts by weight of the crosslinkable fluororubber,
(Ii) 1 to 20 parts by weight of a layered compound organically treated with an organic ammonium salt;
(Iii) 0.3 to 3 parts by weight of a crosslinking agent;
(Iv) A crosslinkable fluororubber composition comprising 4 to 8 parts by weight of a co-crosslinking agent.   The crosslinkable fluororubber composition according to claim 1, further comprising (v) a filler in an amount of 0.1 to 30 parts by weight with respect to 100 parts by weight of the crosslinkable fluororubber.   A sealing material obtained by crosslinking the crosslinkable fluororubber composition according to claim 1.