JP2003211460A - Method for manufacturing regenerated vulcanized fluorinated rubber and composition for unvulcanized fluorinated rubber to be regenerated - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a regenerated fluorinated rubber from a vulcanized fluorinated rubber being a substance to be regenerated through re-vulcanization, a composition for re-vulcanization and a vulcanized fluorinated rubber obtained by regeneration. <P>SOLUTION: After the vulcanized fluorinated rubber (A) to be regenerated is heat-treated to obtain an unvulcanized fluorinated rubber (B) to be regenerated, vulcanization treatment (2) is applied to the unvulcanized fluorinated rubber (B) to be regenerated to obtain the regenerated vulcanized fluorinated rubber (C). In this method for manufacturing the regenerated vulcanized fluorinated rubber (C), the vulcanized fluorinated rubber (A) to be regenerated is obtained by vulcanization treatment (1). <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a regenerated fluorinated rubber from a vulcanized fluororubber which is an object to be regenerated, and a regenerated unvulcanized fluororubber used for revulcanization. Composition.

[0002]

BACKGROUND OF THE INVENTION Since fluororubber has excellent heat resistance, chemical resistance, oil resistance, etc., exposure to various chemicals,
Even in applications where severe usage conditions such as high temperature are imposed, for example, applications in the fields of automobile industry, aircraft industry, semiconductor industry, etc., they are used as materials of various parts.

Since fluororubber is usually vulcanized and used as a molded product or the like, it is necessary to treat scraps, defective products, used molded products and the like at the time of molding, as in general molded products. is there. However, vulcanized fluororubber has excellent properties that hinder chemical treatment, and when burned, it produces corrosive decomposition products, so thermal recycling is not easy. Was.

In recent years, with the increased awareness of environmental protection by reducing the amount of landfill, effective use of resources, etc., there has been a demand for the development of a method for reusing the fluororubber which has been conventionally discarded.

As a method for reusing vulcanized fluororubber, it is difficult to regenerate it as fluororubber because it is conventionally not suitable for chemical treatment or combustion, and it is used as a filler for blending with a fluororubber composition. It was only put into practical use. As a method of using it as a filler, there has been a method of mechanically crushing vulcanized fluororubber by freeze crushing or the like.

Japanese Patent Laid-Open No. 61-69805 discloses a method for improving roll processability during molding by heat-treating a vulcanized fluororubber in the presence of oxygen and adding it to an unvulcanized fluororubber. Is proposed. In this method, a peroxide-vulcanized fluororubber is preferably used, but it is described that this gives an excellent product, and the unvulcanized fluororubber to which the heat-treated fluororubber is added is Since peroxide vulcanization is performed in the example, it is considered to be used as a filler.

As described above, conventionally, the only method for reusing vulcanized fluororubber is to use it as a filler to be added to the fluororubber composition, and there is a problem that the way of reutilization is extremely limited. It was Expanding the way of reuse,
In order to promote the utilization of resources, it has been desired to develop a method of regenerating a vulcanized fluororubber through revulcanization to regenerate the fluororubber.

[0008]

SUMMARY OF THE INVENTION In view of the above circumstances, an object of the present invention is to provide a method for producing a regenerated fluorinated rubber from a vulcanized fluororubber which is an object to be regenerated through revulcanization, and the above revulcanization. To provide a composition for.

[0009]

According to the present invention, a regenerated vulcanized fluororubber (A) is heat-treated to obtain a regenerated unvulcanized fluororubber (B). A method of producing a regenerated vulcanized fluororubber (C), which comprises subjecting (B) to a vulcanization treatment (2), wherein the regenerated vulcanized fluororubber (A) comprises: A method for producing a regenerated vulcanized fluororubber, which is obtained by vulcanization treatment (1).

The present invention is a composition for regenerated non-vulcanized fluororubber (B) used for obtaining regenerated vulcanized fluororubber (C) by vulcanization. The regenerated unvulcanized fluororubber (B) is obtained by heat-treating the regenerated vulcanized fluororubber (A), and is composed of a vulcanizing agent. A) is a composition for regenerated unvulcanized fluororubber obtained by vulcanization treatment (1). The present invention will be described in detail below.

The method for producing recycled vulcanized fluororubber of the present invention is
The regenerated vulcanized fluororubber (A) is heat-treated to obtain a regenerated unvulcanized fluororubber (B), and then the regenerated unvulcanized fluororubber (B) is subjected to a vulcanization treatment (2). To obtain a regenerated vulcanized fluororubber (C).

In the present specification, the above-mentioned "regenerated vulcanized fluororubber (A)" means a vulcanized fluororubber which is an object to be regenerated by the method for producing a regenerated vulcanized fluororubber of the present invention. In the present specification, “vulcanized fluororubber” means fluororubber in a vulcanized state. Vulcanization usually involves curing. The regenerated vulcanized fluororubber (A) is not particularly limited as long as it is a vulcanized fluororubber that is a regenerated material in the regenerated vulcanized fluororubber production method of the present invention. For example, molding of fluororubber It may be scraps generated at times or defective products, or may be used molded products.

In the present specification, the above-mentioned "recycled unvulcanized fluororubber (B)" means that the regenerated vulcanized fluororubber (A) is heat-treated in the method for producing reclaimed vulcanized fluororubber of the present invention. It means the unvulcanized fluororubber obtained. In the present specification, the “unvulcanized fluororubber” means a fluororubber in a substantially unvulcanized state.

In the present specification, the above-mentioned "regenerated vulcanized fluororubber (C)" is a regenerated product obtained by regenerating in the method for producing regenerated vulcanized fluororubber of the present invention, which is the unvulcanized to be regenerated. It means a vulcanized fluororubber obtained by revulcanizing the fluororubber (B). The vulcanized fluororubber for the regenerated vulcanized fluororubber (C) is the same as the vulcanized fluororubber described for the regenerated vulcanized fluororubber (A).

In the method for producing a regenerated vulcanized fluororubber of the present invention, which comprises obtaining the regenerated vulcanized fluororubber (C) from the regenerated vulcanized fluororubber (A), the regenerated unvulcanized fluororubber (B) is used. ) Is, so to speak, an intermediate obtained in the process of obtaining a regenerated vulcanized fluororubber (C) which is a regenerated product obtained from the regenerated vulcanized fluororubber (A) which is a regenerated substance.

In the present specification, the "vulcanized fluororubber" means a fluororubber in a vulcanized state as described above, and a fluororubber in such a state is particularly preferable. It is not limited, and may be, for example, a fluororubber obtained by subjecting an unvulcanized fluororubber or an unvulcanized fluororubber composition to a vulcanization treatment, and the vulcanization in the regenerated vulcanized fluororubber production method of the present invention. Fluorine rubber, that is, both the regenerated vulcanized fluororubber (A) and the regenerated vulcanized fluororubber (C) may be referred to, and vulcanized fluorine in the method for producing regenerated vulcanized fluororubber of the present invention Vulcanized fluororubbers other than rubber are also commonly used terms.

The above-mentioned unvulcanized fluororubber composition is usually
It is composed of an elastomeric fluoropolymer and a vulcanizing additive usually used for rubber vulcanization, and has not been vulcanized. As the vulcanization additive, depending on the vulcanization method used, such as polyol vulcanization and peroxide vulcanization, generally, a vulcanizing agent, a vulcanization accelerator,
Examples thereof include acid acceptors, and of these, other than the vulcanizing agent are usually optional components used as desired to accelerate vulcanization and the like.

In the present specification, the "elastomeric fluorine-containing polymer" is an ethylenic polymer having a fluorine atom directly bonded to a carbon chain which is a main chain, and is obtained by vulcanization. It means one having an elastomeric property such that it becomes the above vulcanized fluororubber.

The vulcanized fluororubber comprises a molecule in which a cross-linking site is bonded to a carbon chain derived from the elastomeric fluoropolymer. In this specification, such a molecule may be referred to as a cross-linking molecule. In the present specification, the "crosslinking site" is a site that is bonded to the elastomeric fluoropolymer by a vulcanization treatment due to its chemical structure, and is a site derived from the vulcanizing agent used in the vulcanization treatment. Yes, it means a part forming a so-called bridge.

The cross-linking site may form a bond between two sites in one molecule of the elastomeric fluoropolymer, or one of the elastomeric fluoropolymers. It may form a bond between a site on one molecule and a site on another molecule. In the present specification, such a site in the molecule of the elastomeric fluorine-containing polymer to which the cross-linking site is bonded may be referred to as a "cross-linking point".

The unvulcanized fluororubber is composed of a crosslinkable fluoropolymer. The crosslinkable fluoropolymer is composed of a carbon chain derived from the elastomeric fluoropolymer, and a small amount of the crosslinkable site may be bonded to the carbon chain. Such a small amount of crosslinking site
Usually, it is a cross-linking site which remains without being decomposed when the regenerated vulcanized fluororubber (A) is heat-treated in the method for producing regenerated vulcanized fluororubber of the present invention. By the above heat treatment,
Usually, it is considered that a small amount of crosslinking site remains. The carbon chain derived from the elastomeric fluoropolymer is
Since it is not usually cut by the above heat treatment, it is substantially the same as the carbon chain derived from the elastomeric fluoropolymer in the crosslinked molecule forming the regenerated vulcanized fluororubber (A). The unvulcanized fluororubber is distinguished from the vulcanized fluororubber in that it has a processable viscosity. Generally, the processable viscosity is preferably 5 to 200 in terms of Mooney viscosity (ML _{1 + 10} , 100 ° C.).

In the present specification, the term "elastomeric fluorine-containing polymer" simply means that the above crosslinking sites are not bonded. Such an elastomeric fluoropolymer is a fluoropolymer that is not vulcanized after being polymerized so as to have elastomeric properties, and is an unvulcanized fluororubber composition as described above. It may be blended with the product. The elastomeric fluoropolymer is distinguished from the crosslinked molecule forming the vulcanized fluororubber in that it has not been subjected to vulcanization treatment and the crosslinked site is not bonded, and is usually the unvulcanized fluororubber. It is also distinguished from the crosslinkable fluorine-containing polymer having the following formula, that is, the one in which a small amount of the crosslinking site is bonded to the carbon chain derived from the elastomeric fluorine-containing polymer.

The regenerated vulcanized fluororubber (C) is obtained by revulcanization as described above. In the present specification, the “revulcanization” means vulcanization of the unvulcanized fluororubber. That is, the revulcanization is performed on the unvulcanized fluororubber composed of the crosslinkable fluoropolymer. The re-vulcanization, the cross-linkable fluoropolymer, is a vulcanization treatment of at least a portion of the cross-linking site is decomposed by the heat treatment which is a post-process is once vulcanization, a small amount of the cross-linking site is bonded. The vulcanization may be carried out for the first time with respect to an unvulcanized fluororubber composition composed of an elastomeric fluoropolymer having no cross-linked site.

The vulcanization method in the revulcanization may be the same as or different from the first vulcanization method. Both the above-mentioned re-vulcanization and the above-mentioned first-time vulcanization carry out primary vulcanization, or primary vulcanization and secondary vulcanization, like ordinary vulcanization. In the regenerated vulcanized fluororubber production method of the present invention, the treatment for performing the first vulcanization is referred to as vulcanization treatment (1), and the treatment for performing the revulcanization is referred to as vulcanization treatment (2).

Since the regenerated vulcanized fluororubber (C) is obtained by revulcanization, the regenerated vulcanizable fluororubber (A) is obtained by the first vulcanization.
Is conceptually distinguished from each other, but as in the case where the vulcanization methods are the same, the molecules and the composition may be the same.

The present inventors heat-treat the regenerated vulcanizable fluororubber (A) composed of a cross-linked molecule in which the above-mentioned cross-linking site is bonded to the carbon chain derived from the above elastomeric fluoropolymer. That the bond at the cross-linking site can be cut before cutting the carbon chain derived from the elastomeric fluoropolymer, and that the state obtained by the heat treatment in this way can be revulcanized. It has been found that the fluororubber can be recycled through revulcanization even if the fluororubber is once vulcanized by performing the heat treatment and the revulcanization, and the method for producing a regenerated vulcanized fluororubber according to the present invention has been found. Was completed.

The method for producing recycled vulcanized fluororubber of the present invention is
First, the regenerated vulcanized fluororubber (A) is heat-treated to obtain a regenerated unvulcanized fluororubber (B), and the regenerated vulcanized fluororubber (A) is vulcanized. It is obtained by (1).

The vulcanization treatment (1) is carried out on an unvulcanized fluororubber composition. The unvulcanized fluororubber composition comprises the elastomeric fluoropolymer and the vulcanization additive as described above.

The vulcanization of fluororubber is generally one using a peroxide, one using a polyol,
Examples thereof include those using polyamine. As the vulcanization treatment (1), it is possible to efficiently perform selective cutting at a cut portion in the heat treatment of the regenerated vulcanized fluororubber (A). Those using oxides are preferable. In the present specification, vulcanization using peroxide may be referred to as peroxide vulcanization.

In the vulcanization using peroxide, a radical generated from peroxide is usually added to a polyfunctional unsaturated compound substantially mixed as a vulcanizing agent to generate another radical, and the latter radical is used as an elastomer. The crosslinkage is formed by a chain reaction including a reaction of adding to the water-soluble fluoropolymer. The polyfunctional unsaturated compound is
In peroxide vulcanization, it is sometimes called a vulcanization aid, a vulcanization accelerator or a co-vulcanization agent. Regarding such a mechanism of peroxide vulcanization, using a dialkyl peroxide as a peroxide and an example of using triallyl cyanurate as the polyfunctional unsaturated compound,
It is shown below.

[0031]

[Chemical 1]

The crosslinking molecule obtained by vulcanization using peroxide usually has a chemical structure derived from the vulcanization aid used at the crosslinking site. Cleavage of the bond at such a crosslinking site can be carried out at a lower temperature than that of the carbon-carbon bond in the carbon chain derived from the elastomeric fluoropolymer in the crosslinking molecule. The above heat treatment in the method for producing a regenerated vulcanized fluororubber of the present invention focuses on the fact that there is a difference in the cutting temperature, and selectively cuts only the bond at the crosslinked site.

When, for example, triallyl isocyanurate [TAIC] is used as the vulcanization aid, the crosslinking site in the obtained crosslinking molecule has a chemical structure derived from TAIC. In the chemical structure derived from TAIC, the carbon chain derived from the allyl group of TAIC is bonded to the nitrogen constituting the saturated 6-membered ring. This carbon chain is usually saturated by crosslinking and is an n-propylene group. It is considered that, by the heat treatment, among the bonds in the n-propylene group, the bond between the nitrogen and the adjacent carbon or the bond between the adjacent carbon and the carbon adjacent thereto is broken.

Since TAIC is said to have the best heat resistance among the vulcanization aids that can be used for peroxide vulcanization, peroxide vulcanization was performed using vulcanization aids other than TAIC. In this case, the bond at the cross-linking site in the obtained cross-linking molecule is cleaved at a lower temperature than the chemical structure derived from TAIC, and therefore the above-mentioned difference in the cleavage temperature is large, and the selective cleavage of the bond at the cross-linking site is performed using TAIC. It seems to be easier than that. Therefore, as the vulcanization treatment (1), if peroxide vulcanization is used, TAIC
Not limited to the case of using, it is preferable.

When the peroxide vulcanization is carried out as the vulcanization treatment (1), the reaction of the vulcanization treatment (1) is likely to proceed due to a chain reaction by radicals, and it is considered that there is little vulcanizing agent remaining. Therefore, in the above heat treatment, the crosslinking reaction no longer substantially occurs. Employing peroxide vulcanization as the vulcanization treatment (1) is preferable also because the crosslinking site can be cut without a crosslinking reaction in the above heat treatment.

The cross-linking molecule obtained by vulcanization using a polyol and the cross-linking molecule obtained by vulcanization using a polyamine are generally such that the cleavage of the bond at the cross-linking site is derived from the elastomeric fluoropolymer. That occurs at a lower temperature than the breaking of the carbon-carbon bond in the carbon chain, which is the same as in the case of peroxide vulcanization. However, when a polyol or a polyamine is used in the vulcanization treatment (1), the vulcanization remaining after the vulcanization treatment (1) without reacting occurs in parallel with the breaking of the bond at the crosslinking site during the heat treatment. Vulcanization proceeds depending on the agent. Therefore, when a polyol or polyamine is used in the vulcanization treatment (1), only the bond at the cross-linking site cannot be selectively thermally decomposed, and it is difficult to reuse it as a fluororubber.

The peroxide used for peroxide vulcanization is not particularly limited, but usually an organic peroxide is preferable because it can easily generate a peroxy radical in the presence of heat or a redox system. The organic peroxide, that is, the organic peroxide is not particularly limited, and examples thereof include 1,1-bis (t-butylperoxy) -3,5.
5-trimethylcyclohexane, 2,5-dimethylhexane-2,5-dihydroperoxide, di-t-butyl peroxide, t-butylcumyl peroxide,
Dicumyl peroxide, 2,5-dimethyl-2,5-
Bis (t-butylperoxy) hexane, α, α-bis (t-butylperoxy) -p-diisopropylbenzene, 2,5-dimethyl-2,5-di (t-butylperoxy) -hexyl-3 -Benzoyl peroxide, t
-Butylperoxybenzene, t-butylperoxybenzoate, 2,5-dimethyl-2,5-di (benzoylperoxy) -hexane, t-butylperoxymaleic acid, t-butylperoxyisopropyl carbonate and the like. To be Among them, a dialkyl type which is an organic peroxide having two alkyl groups is preferable, and 2,5-
Dimethyl-2,5-di (t-butylperoxy) hexane is more preferred. Also preferred is t-butyl peroxybenzoate.

The amount of the above-mentioned organic peroxide to be used is appropriate in consideration of the amount of active groups of the dioxy group or epidioxy group represented by the formula —O—O— in the organic peroxide, the decomposition temperature and the like. It can be determined, and usually, 0.05 to 10 parts by weight is preferable with respect to 100 parts by weight of the elastomeric fluoropolymer, a more preferable lower limit is 1.0 part by weight, and a more preferable upper limit is 5 parts by weight. is there.

In the peroxide vulcanization by the organic peroxide, the vulcanization is remarkably promoted by using the vulcanization aid. The vulcanization aid is not particularly limited, and examples thereof include those conventionally used, and examples of such vulcanization aids include, for example, triaryl derivatives such as triallyl cyanurate and triallyl isocyanurate; triallyl. Aromatic ring-containing compounds such as trimellitate, N, N'-m-phenylene bismaleimide, dipropargyl terephthalate, diallyl phthalate and tetraallyl terephthalate amide; acyclic compounds such as triacrylic formal and triallyl phosphate. Among them, the triazine derivative is preferable from the viewpoint of versatility,
More preferred is triallyl isocyanurate. The amount of the vulcanization aid used is 100% of the elastomeric fluoropolymer 100.
The amount is usually 0.1 to 10 parts by weight, the preferred lower limit is 0.5 part by weight, and the preferred upper limit is 5 parts by weight, preferably 0.5 to 5 parts by weight.

The method of peroxide vulcanization is not particularly limited, and for example, by a method similar to the conventional method, an unvulcanized fluororubber composition comprising an elastomeric fluoropolymer and an additive for vulcanization is used and rolls are used. After kneading, it may be put in a mold to pressurize it for primary vulcanization, and if desired, then secondary vulcanization. Generally, the conditions of primary vulcanization are a temperature of 100 to 200 ° C., a time of 5 to 60 minutes, and a pressure of 2 to 10 minutes.
It is adopted from the range of about MPa, and the secondary vulcanization conditions are a temperature of 150 to 300 ° C. and a time of 30 minutes to 30 hours. As the above-mentioned vulcanization additive, besides the vulcanization agent, a vulcanization accelerator may be used if necessary, and other additives that can be appropriately mixed may be used.

The regenerated vulcanized fluororubber (A) is obtained by the vulcanization treatment (1) and is derived from the elastomeric fluoropolymer in the unvulcanized fluororubber composition. It is composed of a cross-linking molecule in which a cross-linking site is bonded to a carbon chain. The regenerated vulcanized fluororubber (A) is not particularly limited as long as it is such, but from the viewpoint of easy crosslinking, a copolymer obtained from a monomer component containing vinylidene fluoride is vulcanized. It is preferable that the vulcanized fluororubber (A) to be regenerated is, for example, —CFR ¹ —CH ₂ — (R ¹ is crosslinked in the main chain. It can be said that it is composed of a copolymer having a site represented by (). 1,1-Difluoroethylene groups remain in the main chain of the copolymer forming the regenerated vulcanized fluororubber (A). The copolymer obtained from the monomer component containing vinylidene fluoride is the elastomeric fluorine-containing polymer.

The above-mentioned elastomeric fluoropolymer is a polymer having a glass transition point of 25 ° C. or lower. Therefore, the elastomeric fluoropolymer exhibits an elastomeric property having elasticity at room temperature. As the elastomeric fluorine-containing polymer, among copolymers obtained from a monomer component containing vinylidene fluoride, those having a combination and composition showing elastomeric properties can be used.
The elastomeric fluoropolymer is generally amorphous.

The above-mentioned elastomeric fluoropolymer is preferably a copolymer obtained from a monomer component containing vinylidene fluoride and perfluoroolefin and / or perfluorovinyl ether. As the perfluoroolefin and / or perfluorovinyl ether, one kind or two or more kinds can be used, respectively. As the elastomeric fluoropolymer, a copolymer obtained from a monomer component containing vinylidene fluoride and perfluoroolefin is more preferable.

As the perfluoroolefin, the
Trafluoroethylene, hexafluoropropylene, etc.
Can be mentioned. As the perfluoro vinyl ether
Is a perfluoroalkyl group having 1 to 6 carbon atoms.
-Fluoro (alkyl vinyl ether), the following general formula C
F₂= CFO (CF₂CFX¹O)_n1-(CF₂CF₂CF
₂O)_n2-Rf¹ (In the formula, X¹Is a fluorine atom or triflu
Represents an oromethyl group, Rf¹Is a C1-20 fluorine
Rhopolyoxyalkyl group or C1-8 perfluor
Represents an alkyl group, n1 and n2 are the same or different,
It represents an integer of 0 to 5. However, n1 + n2 ≧ 1. )
And fluorovinyl ethers represented by

The above-mentioned elastomeric fluoropolymer is a vinylidene fluoride and perfluoroolefin and / or perfluorovinyl ether, and a crosslinkable group-containing monomer is added to 0.01% of the monomer component of the above elastomeric fluoropolymer. The polymer is preferably polymerized at a ratio of 3 mol%. In the present specification, the “crosslinkable group-containing monomer” means an ethylenically unsaturated compound having at least one iodine atom and / or bromine atom as a crosslinkable group in the molecule.

The elastomeric fluoropolymer obtained from the monomer component containing the above-mentioned crosslinkable group-containing monomer has iodine and / or iodine bonded to carbon constituting the main chain and / or carbon constituting the side chain. Or it will have bromine. This iodine and / or bromine is vulcanized (1) as described above.
When peroxide vulcanization is carried out, the radical active sites are donated. That is, such an elastomeric fluorine-containing polymer has an unpaired electron because iodine and / or bromine are easily desorbed by radicals generated from peroxide in peroxide vulcanization,
This unpaired electron is added to the unsaturated bond of the vulcanization aid to form a bond and efficiently form a crosslink. Since the elastomeric fluoropolymer has no iodine and no bromine, it is highly resistant to attack by radicals.
Peroxide vulcanization is difficult to proceed. In the present specification, the phrase “having no iodine and having no bromine” means that iodine [I] does not exist as an atom constituting a polymer such as an elastomeric fluoropolymer, and bromine [Br] does not exist. Means that there is no.

The above elastomeric fluorine-containing polymer is
Obtained from a monomer component containing the crosslinkable group-containing monomer
If so, vinylidene fluoride and perf
Luoroolefin and / or perfluorovinyl ether
The segment obtained by polymerizing
formula X^Two-[A- (Y)_n3]_n4-X^Three (In the formula, X^TwoAnd X^ThreeAre the same or different,
Or a group derived from a chain transfer agent or a modification after polymerization
Represents the resulting group. Y has iodine and / or bromine
Represents a carbon chain. n3 represents an integer of 0 to 50 and n4 is 1
Represents an integer of 5; However, n3 × n4 ≧ 1. n3
The Ys may be the same or different. n4
[A- (Y)_n3] Are the same or different
Also, if different, n4 A, n4 Y and n4
The n3's may be the same or different. )
It is preferred to have the chemical structure

Y in the above formula may be introduced by any method of block copolymerization, graft copolymerization, alternating copolymerization or random copolymerization. X ² and X ³ are
It can be arbitrarily changed by selecting the kind and addition amount of the polymerization initiator and / or the chain transfer agent used during the polymerization of the elastomeric fluorine-containing polymer, and the end group obtained by the polymerization can be modified. Can also be changed arbitrarily. As X ² and X ³ , a carboxyl group, an alkoxycarbonyl group, a nitrile group, an iodine atom, a bromine atom or a sulfonic acid group is preferable.

The crosslinkable group-containing monomer has the following general formula:

[0050]

[Chemical 2]

Iodine-containing fluorinated vinyl a represented by
Tell etc. are mentioned. The iodine-containing fluorinated vinyl ether
A preferred example of ether is ICH_TwoCF_TwoCF_TwoO
CF = CF_Two, I (CH_TwoCF_TwoCF_TwoO)_TwoCF = C
F_Two, I (CH_TwoCF_TwoCF_TwoO)_ThreeCF = CF_Two, I
CH_TwoCF_TwoCF_TwoOCF (CF_Three) CF_TwoOCF = C
F_Two, ICH_TwoCF_TwoCF_TwoO [CF (CF_Three) CF_Two
O]_TwoCF = CF_Two Etc., ICH_TwoCF_TwoCF_TwoOCF = CF_Two Is more preferable.

The elastomeric fluorine-containing polymer can be produced, for example, by a conventionally known method, and for example, a polymerization method such as emulsion polymerization or suspension polymerization can be used.

The cross-linking molecule in the regenerated vulcanized fluororubber (A) has a carbon chain derived from the elastomeric fluoropolymer and a cross-linking site bonded to the carbon chain and is treated by the vulcanization treatment (1). It was obtained. Therefore, the carbon chain may have a difference in chemical structure from the elastomeric fluoropolymer, in addition to having a crosslinking point at which a crosslinking site is bonded. When the peroxide is used in the vulcanization treatment (1), the carbon chain has iodine and / or iodine which the elastomeric fluoropolymer has, as is clear from the mechanism described above for the peroxide vulcanization. Or, it does not have bromine in the molecule.

In the method for producing regenerated vulcanized fluororubber of the present invention, the regenerated vulcanized fluororubber (A) is then subjected to heat treatment.

The heat treatment is preferably carried out at 240 to 400 ° C. According to the thermogravimetry (TG measurement), the decomposition temperature of the fluororubber is usually over 400 ° C., and at the temperature within this range, the crosslink forming the regenerated vulcanized fluororubber (A) is formed. It is considered that the carbon chain derived from the above-mentioned elastomeric fluoropolymer in the molecule is cleaved.
On the other hand, the cross-linked site of fluororubber obtained by peroxide vulcanization is usually decomposed at a temperature of 240 ° C or higher. Therefore, it is lower than the temperature at which the carbon chain is cleaved,
A temperature equal to or higher than the temperature at which the cross-linking site starts to be cut, that is, 2
By carrying out a heat treatment at 40 to 400 ° C., in the crosslinked molecule forming the regenerated vulcanized fluororubber (A), the carbon chain derived from the elastomeric fluoropolymer is not substantially cut, and Only the crosslinking site can be selectively decomposed.

The heating conditions for the above heat treatment depend on the type and degree of vulcanization of the regenerated vulcanized fluororubber (A), but the heating time is further determined from the point that the crosslinked site can be sufficiently cut. Although it cannot be generally stated that it depends on processing conditions such as a heating device, heating temperature, and pressure, when heating at 300 ° C., the cross-linking site can be sufficiently cut in, for example, 168 hours or less. It is 24 to 100 hours without applying pressure. The heat treatment is preferably performed in air (in an oxygen-containing atmosphere) from the viewpoint of easy decomposition.

In the method for producing regenerated vulcanized fluororubber of the present invention, the regenerated vulcanized fluororubber (A) is heat-treated to obtain regenerated unvulcanized fluororubber (B). The regenerated unvulcanized fluororubber (B) is composed of a crosslinkable fluoropolymer as described above for the unvulcanized fluororubber, and has a processable viscosity.

The crosslinkable fluoropolymer is composed of a carbon chain derived from the elastomeric fluoropolymer as described above. Since this carbon chain is derived from the cross-linking molecule in the regenerated vulcanized fluororubber (A),
For example, when peroxide is used in the vulcanization treatment (1),
Like the cross-linking molecule, it does not have the iodine and bromine that the elastomeric fluoropolymer had.

The crosslinkable fluoropolymer may be one in which a small amount of crosslinking site is bonded to the carbon chain derived from the elastomeric fluoropolymer. The cross-linking site is
As a result of the above heat treatment, a small amount is usually bonded to the carbon chain, but as a result of sufficient decomposition by the heat treatment, the carbon chain may not be bonded. The cross-linking site bonded to the carbon chain forms a bridge. Therefore, the cross-linking site in the cross-linking molecule forming the regenerated vulcanized fluororubber (A) is partially cut by the heat treatment, and is not cross-linked, but on the carbon chain derived from the elastomeric fluoropolymer. Those that are still bound to (hereinafter referred to as "crosslinking site residue") are not included in the "crosslinking site bound to the carbon chain". It can be said that it is not bound to a chain.

In the cross-linking site of the cross-linking molecule which constitutes the regenerated vulcanized fluororubber (A), at least the vulcanization treatment (1) is found at the position where the bond is broken by the heat treatment.
When peroxide is used, especially when triallyl isocyanurate is used as a vulcanization aid, the chain ends are unstable due to cleavage, and because of the instability, it usually stabilizes spontaneously to a carboxyl group. . Therefore, in this case, the crosslinkable fluoropolymer has a carboxyl group in the side chain. This side chain is composed of a part of the chemical structure derived from the cross-linking site. The side chain having a carboxyl group is one of the above-mentioned crosslinking site residues.

In the regenerated unvulcanized fluororubber (B), the regenerated vulcanized rubber (A) is insoluble in polar solvents such as acetone and tetrahydrofuran, but is soluble in the polar solvents. Can be distinguished.

Since the regenerated unvulcanized fluororubber (B) is obtained by decomposing the crosslinked site of the crosslinked molecule of the regenerated vulcanized fluororubber (A), it is processed. Has a possible viscosity. Therefore, the regenerated unvulcanized fluororubber (B) can be treated in substantially the same manner as the unvulcanized fluororubber composition, and can be vulcanized by various vulcanization methods. This vulcanization treatment is the vulcanization treatment (2) in the method for producing a regenerated vulcanized fluororubber of the present invention.

The mechanism of vulcanization in the above-mentioned vulcanization treatment (2) is not particularly limited, and examples thereof include those comprising reacting the crosslinkable site of the above-mentioned crosslinkable fluoropolymer. The crosslinkable site, (i) -CFR ² -CH
_2- (R ² represents a fluorine atom or a residue of a cross-linking site) in the main chain, or (ii) an ionic group. The vinylidene described above as being preferably contained in the monomer component of the elastomeric fluoropolymer is usually a 1,1-difluoroethylene group in which R ² is a fluorine atom in the formula (i). It is a divalent group derived from fluoride. The crosslinking site residue as R ^{2 in} the formula (i) is as described above as being a part of the crosslinking site cleaved by the heat treatment. The ionic group is generated as a result of the bond at the cross-linking site being cut by the heat treatment of the regenerated vulcanized fluororubber (A), and examples thereof include the above-mentioned carboxyl group. From the viewpoint of high crosslinkability, the above-mentioned crosslinkable site is preferably the above-mentioned site (i), and the above-mentioned site (i) is preferably a 1,1-difluoroethylene group.

As the vulcanization method comprising reacting the sites of (i), a vulcanization method using a polyol,
And a vulcanization method using polyamine. In this specification, the vulcanization method using a polyol may be referred to as a polyol vulcanization, and the vulcanization method using a polyamine may be referred to as a polyamine vulcanization.

The polyol vulcanization used as the vulcanization treatment (2) is generally carried out by using a nucleophile obtained by reacting calcium hydroxide with an onium compound used as a vulcanization accelerator to prepare a 1,1-difluoroethylene group. Dehydrofluorination is carried out from the above-mentioned site (i), etc., and a polyol compound used as a vulcanizing agent is added to the resulting double bond to form a crosslink, thereby crosslinking. The generated hydrogen fluoride can be eliminated by reacting with magnesium oxide used as an acid acceptor.

As the polyol compound used in the vulcanization used in the vulcanization treatment (2), for example, a polyol compound conventionally known as a vulcanizing agent for fluororubber can be used. As such a polyol compound, for example, a polyhydroxy compound is preferable, and among them, a polyhydroxy aromatic compound is more preferable from the viewpoint of easily obtaining a fluororubber excellent in heat resistance, mechanical strength and the like.

Examples of the polyhydroxy aromatic compound include 2,2-bis (4-hydroxyphenyl) propane [bisphenol A], 2,2-bis (4-hydroxyphenyl) perfluoropropane [bisphenol AF] and resorcin. , 1,3-trihydroxybenzene, 1,7-dihydroxynaphthalene, 2,7-dihydroxynaphthalene, 1,6-dihydroxynaphthalene,
4,4'-dihydroxydiphenyl, 4,4'-dihydroxystilbene, 2,6-dihydroxyanthracene, hydroquinone, catechol, 2,2-bis (4-hydroxyphenyl) butane [bisphenol B], 4,
4-bis (4-hydroxyphenyl) valeric acid, 2,2-
Bis (4-hydroxyphenyl) tetrafluorodichloropropane, 4,4'-dihydroxydiphenyl sulfone, 4,4'-dihydroxydiphenyl ketone, tri (4-hydroxyphenyl) methane, 3,3 ', 5
5'-tetrachlorobisphenol A, 3,3 ', 5
5'-tetrabromobisphenol A and the like can be mentioned.
These polyhydroxy aromatic compounds may be alkali metal salts or alkaline earth metal salts, etc., but an acid is used for coagulation of cross-linking molecules to form the obtained regenerated vulcanized fluororubber (C). It is preferable not to use these metal salts.

As the vulcanization accelerator used for the vulcanization of the polyol used in the vulcanization treatment (2), for example, an onium compound generally known as a vulcanization accelerator for the polyol vulcanization of fluororubber is used. You can Examples of such onium compounds include ammonium compounds such as quaternary ammonium salts and phosphonium compounds such as quaternary phosphonium salts, as well as oxonium compounds and sulfonium compounds. Among them, quaternary ammonium salts are mentioned. And quaternary phosphonium salts are preferred.

Examples of the quaternary ammonium salt include 8
-Methyl-1,8-diaza-bicyclo [5.4.0]-
7-undecenium chloride, 8-methyl-1,8-diaza-bicyclo [5.4.0] -7-undecenium iodide, 8-methyl-1,8-diaza-bicyclo [5.4. 0] -7-undecenium hydroxide, 8-methyl-1,8-diaza-bicyclo [5.4.
0] -7-undecenium-methylsulfate, 8-
Ethyl-1,8-diaza-bicyclo [5.4.0] -7
-Undecenium bromide, 8-propyl-1,8-diaza-bicyclo [5.4.0] -7-undecenium bromide, 8-dodecyl-1,8-diaza-bicyclo [5.4.0] -7-Undecenium chloride, 8-dodecyl-1,8-diaza-bicyclo [5.4.0] -7
-Undecenium Hydroxide, 8-Eicosyl-
1,8-diaza-bicyclo [5.4.0] -7-undecenium chloride, 8-tetracosyl-1,8-diaza-bicyclo [5.4.0] -7-undecenium chloride, 8- Benzyl-1,8-diaza-bicyclo [5.
4.0] -7-Undecenium chloride, 8-benzyl-1,8-diaza-bicyclo [5.4.0] -7-undecenium hydroxide, 8-phenethyl-1,8
-Diaza-bicyclo [5.4.0] -7-undecenium chloride, 8- (3-phenylpropyl) -1,8-
Examples thereof include diaza-bicyclo [5.4.0] -7-undecenium chloride.

Examples of the quaternary phosphonium salt include tetrabutylphosphonium chloride, benzyltriphenylphosphonium chloride, benzyltrimethylphosphonium chloride, benzyltributylphosphonium chloride and the like.

The polyol compound used for the above-mentioned polyol vulcanization is based on 100 parts by weight of the crosslinkable fluoropolymer.
Usually, it is 0.5 to 5 parts by weight, the preferred lower limit is 1 part by weight, and the preferred upper limit is 2 parts by weight, preferably 1 to 2 parts.
Parts by weight. The vulcanization accelerator used for the above-mentioned polyol vulcanization is usually 0.2 to 10 parts by weight per 100 parts by weight of the crosslinkable fluoropolymer, the preferred lower limit is 0.5 parts by weight, and the preferred upper limit is 5 parts by weight. And preferably 0.5
~ 5 parts by weight.

The polyol vulcanization used as the vulcanization treatment (2) can be carried out in the same manner as in the prior art. For example, the crosslinkable fluorine-containing polymer and the above-mentioned vulcanizing agent, and optionally a vulcanization accelerator, Furthermore, there may be mentioned a method in which other additives that can be appropriately mixed are kneaded with a roll, put into a mold to pressurize, and then primary vulcanization, and then secondary vulcanization. Generally, the conditions for primary vulcanization are
The temperature is 100 to 200 ° C., the time is 10 to 180 minutes, and the pressure is about 2 to 10 MPa. The secondary vulcanization conditions are the temperature 150 to 300 ° C. and the time is about 30 minutes to 30 hours. To be done.

The polyamine vulcanization used as the vulcanization treatment (2) is generally obtained by dehydrofluorinating from the above-mentioned site (i) such as 1,1-difluoroethylene group which is the above-mentioned crosslinkable site. A polyamine compound used as a vulcanizing agent is added to the obtained double bond to form a bridge, and further dehydrofluorination is carried out at the cross-linking point to form a carbon-nitrogen double bond, thereby cross-linking. The generated hydrogen fluoride can be eliminated by reacting with magnesium oxide used as an acid acceptor.

Polyamine used for vulcanization treatment (2) The polyamine compound used for vulcanization is a primary amine or secondary amine having two or more basic nitrogen atoms bonded in the molecule, and in many cases, these are used. Is used in the form of a salt with reduced reactivity. Examples of the polyamine compound include alkylenediamines such as ethylenediaminecarbamate, hexamethylenediaminecarbamate, and 4,4-diaminecyclohexylmethanecarbamate; N,
Examples thereof include Schiff bases such as N'-dicinnamylidene-1,6-hexamethylenediamine. In addition, an aromatic polyamine compound having poor basicity can be used as a vulcanizing agent in combination with another basic compound. Examples of the other basic compound include diphenylguanidine, di-O-triguanidine, diphenylthiourea, 2-mercaptoimidazoline, and the like, and a vulcanization accelerator for synthetic rubbers having an amino group in the molecule. [-NH _2] and / or a compound having an imino group [-NH-], it may be a divalent metal hydroxides. Usually, the amount of the polyamine compound used is preferably 0.5 to 5 parts by weight based on 100 parts by weight of the unvulcanized fluororubber (B) to be regenerated.

As the vulcanization method (2), which comprises reacting an ionic group such as a carboxyl group in (ii), that is, a vulcanization method utilizing an ionic group,
For example, one using a metal oxide may be mentioned. Such vulcanization is sometimes called ionic crosslinking. In the case of vulcanization in which a carboxyl group is reacted as the ionic group, a metal oxide such as zinc oxide is allowed to act on the carboxyl group to form an ionic cluster between two carboxyl groups and a metal atom such as zinc. Therefore, it is considered that the compound is crosslinked.

The metal oxide used for the above ionic crosslinking is
Per 100 parts by weight of unvulcanized fluororubber (B) to be regenerated,
0.5 to 50 parts by weight is preferable. For the ionic crosslinking, a method generally used for vulcanizing rubber can be used. The above-mentioned ionic crosslinking is generally performed by blending a small amount of fatty acid such as stearic acid.

As the vulcanization method of the vulcanization treatment (2), as described above, the crosslinkable fluoropolymer forming the unvulcanized fluororubber (B) to be regenerated is an elastomeric compound containing iodine and bromine. Even those derived from fluoropolymers are not suitable for peroxide vulcanization because they are less susceptible to radical attack because they have no iodine and no bromine as a result of vulcanization treatment (1). The peroxide-vulcanized fluororubber disclosed in the above-mentioned JP-A-61-69805 has no iodine in the molecule, no bromine, and after heat treatment. It is considered that the above-mentioned peroxide vulcanization does not cause vulcanization, so it is considered that the heat-treated fluororubber is used as a filler.

In carrying out the vulcanization treatment (2), the unvulcanized fluororubber (B) to be regenerated may be a blend of unvulcanized fluororubber. The unvulcanized fluororubber is not particularly limited as long as it can be vulcanized by the vulcanization treatment (2), and is selected according to the vulcanization method used. When polyol vulcanization or polyamine vulcanization is performed as the vulcanization treatment (2), a fluoropolymer having a 1,1-difluoroethylene group is preferable, and when ionic crosslinking is performed, for example, ethylene having a carboxyl group is used. A fluoropolymer obtained from a monomer component containing a polyunsaturated compound can be used.

The vulcanization treatment (2) is usually carried out so that the obtained regenerated vulcanized fluororubber (C) has a desired shape.
Simultaneous molding. The molding method is not particularly limited, and examples thereof include known methods such as a method of heating and compression using a mold, a method of press-fitting into a heated mold, a method of extrusion steam heating with an extruder, and the like. The above molding is usually performed in primary vulcanization.

In the vulcanization treatment (2), in order to improve the properties of the regenerated vulcanized fluororubber (C) to be obtained, the molded article obtained by the above primary vulcanization is further heated to carry out the secondary vulcanization. May be performed.

The regenerated vulcanized fluororubber (C) obtained by the method for producing regenerated vulcanized fluororubber of the present invention comprises, in addition to the crosslinking molecule and the vulcanization additive, other compounding agents as required. May be. The above-mentioned other compounding agents can be compounded in the unvulcanized fluororubber composition, the regenerated vulcanized fluororubber (A) and / or the regenerated unvulcanized fluororubber (B). The above-mentioned other compounding agents are not particularly limited, and for example, various compounding agents generally used for rubber can be used. Examples of such compounds include fillers, processing aids, plasticizers, softeners. , Antiaging agents and the like.

Examples of the filler include filler metal oxides such as magnesium oxide, calcium oxide, titanium oxide, silicon oxide and aluminum oxide; metal hydroxides such as magnesium hydroxide, aluminum hydroxide and calcium hydroxide. Carbonates such as magnesium carbonate, aluminum carbonate, calcium carbonate and barium carbonate; silicates such as magnesium silicate, calcium silicate, sodium silicate and aluminum silicate; sulfates such as aluminum sulfate, calcium sulfate and barium sulfate; synthetic hydrotalcite In addition to metal sulfides such as molybdenum disulfide, iron sulfide and copper sulfide, diatomaceous earth, asbestos, lithopone (zinc sulfide / barium sulfide), graphite, carbon black, carbon fluoride, calcium fluoride, coke, wet silica, Dry silica, fine quartz powder, Namarihana, talc, mica powder, wollastonite, carbon fiber, aramid fiber, various whiskers, glass fiber, organic reinforcing agents, organic fillers and the like.

Examples of the processing aid include higher fatty acids such as stearic acid, oleic acid, palmitic acid and lauric acid; higher fatty acid salts such as sodium stearate and zinc stearate; higher fatty acids such as stearic acid amide and oleic acid amide. Fatty acid amides; higher fatty acid esters such as ethyl oleate; higher aliphatic amines such as stearylamine and oleylamine; petroleum waxes such as carnauba wax and ceresin wax; polyglycols such as ethylene glycol, glycerin and diethylene glycol; vaseline, paraffin, etc. In addition to other aliphatic hydrocarbons,
Silicone oil, silicone polymer, low molecular weight polyethylene, phthalates, phosphates,
Examples thereof include rosin, dialkylamine, halogenated dialkylamine, dialkyl sulfone, halogenated dialkyl sulfone, and surfactant.

Examples of the plasticizer include phthalic acid derivatives,
Examples thereof include sebacic acid derivatives, and examples of the softening agent include lubricating oil, process oil, coal tar, castor oil,
Examples thereof include calcium stearate, and examples of the antiaging agent include phenylenediamines, phosphates, quinolines, cresols, phenols, and dithiocarbamate metal salts. As the above-mentioned other compounding agents, coloring agents, ultraviolet absorbers, flame retardants,
Oil resistance improver, foaming agent, scorch inhibitor, tackifier,
A lubricant and the like can be optionally mixed.

The regenerated vulcanized fluororubber (C) obtained by the method for producing regenerated vulcanized fluororubber of the present invention is excellent in heat resistance, oil resistance, solvent resistance, chemical resistance, weather resistance, etc., It can be used in the same manner as vulcanized fluororubber obtained by first vulcanization, and can withstand various uses, even under severe conditions such as high temperature and exposure to chemicals. Have.

Examples of the use of the regenerated vulcanized fluoro rubber (C) include parts for automobiles. Examples of parts for automobiles are an engine main body; an engine main motion system, a valve system, a lubrication / cooling system; a fuel system, an intake / exhaust system,
Drive system transmission systems, etc .; chassis steering systems, brake systems, etc .; basic electrical components of electrical components, control system electrical components, and electrical components such as electrical components.
Applications of the regenerated vulcanized fluororubber (C) also include sealing materials, bellows, diaphragms, hoses, tubes, electric wires, etc., which are particularly heat resistant, oil resistant, fuel oil resistant, LLC resistant and Those that require steam resistance are suitable. Examples of the seal material include gaskets, non-contact type and contact type packings, and the like, for example, self-sealing packing, piston ring, split ring type packing, mechanical seal,
Examples include oil seals.

The recycled vulcanized fluororubber (C) can be used, for example, in the following specific uses. Gaskets such as cylinder head gaskets, cylinder head cover gaskets, oil pan packings, general gaskets, etc. in automobile engine bodies; O-rings,
Sealing materials such as packing and timing belt cover gaskets; hoses such as control hoses; anti-vibration rubber for engine mounts.

Shaft seals such as crankshaft seals and camshaft seals in the main motion system of automobile engines. Valve stem oil seals for engine valves in the valve trains of automobile engines. In the lubrication and cooling system of automobile engines, engine oil coolers such as engine oil coolers, oil return hoses, seal gaskets, water hoses around radiators, vacuum pump oil hoses for vacuum pumps, etc.

In the fuel system of automobiles, oil seals, diaphragms, valves, etc. of fuel pumps; fuel hoses such as filler (neck) hoses, fuel supply hoses, fuel return hoses, vapor (evaporation) hoses; in-tank hoses of fuel tanks , Filler seal, tank packing,
In-tank fuel pump mount, etc .; tube body of fuel tube, connector O-ring, etc .; injector cushion ring, injector seal ring, injector O-ring, pressure regulator diaphragm, check valves, etc. of fuel injection device;
Needle valve petals for carburetors, acceleration pump pistons, flange gaskets, control hoses, etc .; valve seats for complex air control systems (CAC), diaphragms, etc.

In an automobile intake / exhaust system, an intake manifold packing of a manifold, an exhaust manifold packing, an EGR (circulation at the time of exhaust) diaphragm, a control hose, an emission control hose, etc.
BPT diaphragm, AB valve afterburn prevention valve seat, throttle throttle body packing, turbocharger turbo oil hose (supply), turbo oil hose (return), turbo air hose, intercooler hose, turbine shaft seal, etc.

In the transmission system of an automobile,
Transmission-related bearing seals, oil seals, O-rings, packing, torque converter hoses, AT
Mission oil hose, ATF hose, O-ring, packing, etc. Power steering oil hoses for automobile steering systems. In automobile brake systems, oil seals, O-rings, packings, brake oil hoses, master back atmospheric valves, vacuum valves, diaphragms, master cylinder piston cups (rubber cups), caliper seals, boots, etc.

In the basic electric components of automobiles, an electric wire (harness) insulator, a sheath, a tube of a harness exterior component, and the like. Coating materials for various sensor wires of automobile control system electrical components. O-rings, packings, cooler hoses, etc. of car air conditioners in electrical equipment of automobiles.

Except for automobiles, for example, packings for oil resistance, chemical resistance, heat resistance, steam resistance and / or weather resistance, other sealing materials, O-rings, hoses, diaphragms, valves, etc. in transportation means such as ships and aircraft; Packing, O-ring, sealing material as described above in the plant,
Diaphragms, valves, hoses, rolls, tubes; chemical resistant coatings, linings; similar packings, O-rings, hoses, seals, belts, diaphragms, valves, rolls in food plant equipment and food equipment (including household items) , Tube; similar packing, O-ring, hose, sealing material, diaphragm, valve, tube in nuclear power plant equipment; similar packing, O-ring, hose, sealing material, diaphragm, valve, roll, tube in general industrial parts , Linings, mandrels, electric wires, flexible joints, belts, rubber plates, weather strips, roll blades for PPC copiers, etc.

The composition for regenerated unvulcanized fluororubber of the present invention is used for obtaining a regenerated vulcanized fluororubber (C) by vulcanization, and the regenerated unvulcanized fluororubber (B) is used. And a vulcanizing agent. The regenerated vulcanized fluororubber (C), the regenerated unvulcanized fluororubber (B) and the vulcanizing agent are the same as those described above for the method for producing the regenerated vulcanized fluororubber of the present invention. It is the vulcanization treatment (2) in the above regenerated vulcanized fluororubber manufacturing method.
Therefore, polyol, polyamine and / or metal oxide can be used as the vulcanizing agent.

The composition for regenerated unvulcanized fluororubber of the present invention comprises, in addition to the regenerated unvulcanized fluororubber (B) and the vulcanizing agent, a method for producing a regenerated vulcanized fluororubber of the present invention. In the same manner as described above with respect to the regenerated unvulcanized fluororubber (B), the vulcanization additive other than the vulcanizing agent, the compounding agent, and / or the unvulcanized fluororubber may be used. Good. The composition for regenerated unvulcanized fluororubber of the present invention needs to have a processable viscosity. The above-mentioned viscosity is the same as that described above for the regenerated vulcanizable fluororubber (B) in the regenerated vulcanized fluororubber production method of the present invention.

Since the composition for unvulcanized fluororubber to be regenerated according to the present invention is the composition described above, it is possible to regenerate the vulcanized fluororubber by performing the vulcanization treatment (2). It is a thing. When the composition for regenerated unvulcanized fluororubber of the present invention is subjected to the above-mentioned vulcanization treatment (2), the molding as described above for the method for producing a regenerated vulcanized fluororubber of the present invention is usually performed at the same time. The composition for regenerated unvulcanized fluororubber of the present invention can be expressed in the following two ways.

The first regenerated unvulcanized fluororubber composition of the present invention is used for obtaining a regenerated vulcanized fluororubber (C) by vulcanization. (B) and a vulcanizing agent, and the regenerated unvulcanized fluororubber (B) is a regenerated vulcanized fluororubber (A).
Is obtained by heat treatment, and the regenerated vulcanized fluoro rubber (A) is obtained by vulcanization treatment (1).

The second composition for regenerated unvulcanized fluororubber of the present invention is used to obtain a regenerated vulcanized fluororubber (C) by vulcanization, and is used for regenerated unvulcanized fluororubber. (B) and a vulcanizing agent, the regenerated unvulcanized fluororubber (B) is a crosslinkable fluoropolymer, and the crosslinkable fluoropolymer contains iodine. In other words, it is characterized by having no bromine and having an ionic group such as a carboxyl group in the side chain.

In the second composition for regenerated unvulcanized fluororubber of the present invention, the above-mentioned crosslinkable fluoropolymer is as described above in the method for producing a regenerated vulcanized fluororubber of the present invention. Therefore, the crosslinkable fluoropolymer may be obtained by heat-treating a vulcanized fluororubber obtained by peroxide vulcanization. In this case, the result of performing peroxide vulcanization is It does not have iodine and does not have bromine, and as a result of decomposing the crosslinking site by the above heat treatment, it has an ionic group such as a carboxyl group in the side chain.

A regenerated vulcanized fluororubber which is obtained from the above composition for regenerated unvulcanized fluororubber is also one aspect of the present invention. As described above, this regenerated vulcanized fluororubber is the regenerated vulcanized fluororubber (C) obtained by the method for producing regenerated vulcanized fluororubber of the present invention.

The method for producing a regenerated vulcanized fluororubber of the present invention comprises:
Further, the present invention is characterized in that a regenerated vulcanized fluororubber is obtained by vulcanizing the composition for regenerated unvulcanized fluororubber. This method for producing recycled vulcanized fluororubber is referred to as the second method for producing recycled vulcanized fluororubber of the present invention. The vulcanization treatment is the vulcanization treatment (2) described above in the method for producing a recycled vulcanized fluororubber of the present invention,
The regenerated vulcanized fluororubber is the regenerated vulcanized fluororubber (C) described above in the method for producing a regenerated vulcanized fluororubber of the present invention.
Is. Therefore, the regenerated vulcanized fluororubber (C) can be regenerated also by the second method for producing regenerated vulcanized fluororubber of the present invention.

[0102]

EXAMPLES Example 1 MT carbon black (trade name: Thermax N- was added to 100 parts by weight of fluororubber (VdF / TFE / HFP copolymer having iodine, trade name: Daiel G-952, manufactured by Daikin Industries, Ltd.). 990, manufactured by Cancarb), 20 parts by weight, triallyl isocyanurate (TAI)
C, manufactured by Nippon Kasei Co., Ltd.) 4 parts by weight and peroxide (trade name: Perhexa 2.5B, manufactured by NOF CORPORATION) 1.5 parts by weight are kneaded using a two-roll mill and pressed at 160 ° C. for 10 minutes. After vulcanization, oven vulcanization at 180 ° C for 4 hours,
Fluorine rubber that can be regenerated by peroxide vulcanization (A)
Was produced. This regenerated vulcanized fluororubber (A) was crushed using a two-roll mill and heat-treated in an oven at 300 ° C. for 70 hours to produce a regenerated unvulcanized fluororubber (B). This regenerated unvulcanized fluororubber (B) was kneaded with rolls in the composition shown in Table 1 and then subjected to polyol vulcanization, followed by press vulcanization at 170 ° C. for 20 minutes, and then at 230 ° C. for 24 hours in an oven. Vulcanized to produce a regenerated vulcanized fluororubber (C). The vulcanizability of the above kneaded compound was measured using a curast meter (manufactured by JSR).
The measured results are shown in Table 2. With respect to the regenerated vulcanized fluororubber (C), the tensile strength and the elongation at break were measured according to JIS K 6251, and the hardness (shoe A) was measured according to JIS K 6253. Moreover, the compression set test was implemented. Table 3 shows the measured results.

Example 2 Instead of carrying out polyol vulcanization, polyamine vulcanization was carried out according to the formulation shown in Table 1, press vulcanization was carried out at 160 ° C. for 20 minutes at the time of preparation of regenerated vulcanized fluororubber (C), and oven vulcanization was carried out. Regenerated vulcanized fluororubber (C) was prepared and measured in the same manner as in Example 1 except that vulcanization was performed at 200 ° C. for 24 hours. The measured results are shown in Tables 2 and 3.

Example 3 A regenerated vulcanized fluororubber (in the same manner as in Example 1) was prepared in the same manner as in Example 1 except that ionic vulcanization and polyol vulcanization were used in combination instead of polyol vulcanization. C) was prepared and measured. The measured results are shown in Tables 2 and 3.

Comparative Example 1 100 parts by weight of a fluororubber (VdF / TFE / HFP copolymer having iodine, trade name: Daier G-952, manufactured by Daikin Industries, Ltd.) was used, and a polyol vulcanization was carried out with the composition shown in Table 1. And press vulcanization at 170 ° C. for 20 minutes,
Oven vulcanization was performed at 230 ° C. for 24 hours to produce a fluororubber, and the same measurement as in Example 1 was performed. The measured results are shown in Tables 2 and 3.

Comparative Example 2 100 parts by weight of fluororubber (VdF / TFE / HFP copolymer having iodine, trade name: Daier G-952, manufactured by Daikin Industries, Ltd.) was used, and polyamine vulcanization was carried out with the composition shown in Table 1. And press vulcanization at 160 ° C. for 20 minutes,
Oven vulcanization was performed at 200 ° C. for 24 hours to produce a fluororubber, and the same measurement as in Example 1 was performed. The measured results are shown in Tables 2 and 3.

[0107]

[Table 1]

In Table 1, each trade name and abbreviation are shown below. Bisphenol AF: 2,2-bis (4-hydroxyphenyl) perfluoropropane DBU-B: 8-benzyl-1,8-diaza-bicyclo [5.4.0] -7-undecenium hydroxide vulcanization Agent V-3: N, N'-dicinnamylidene-1,6-
Hexanediamine, Daikin Kogyo Cardic # 2000: Calcium hydroxide, Omi Chemical Co., Ltd. Kyowamag 150: Highly active magnesium oxide, Kyowa Chemical Co., Ltd. Kyowamu 30: Low activity magnesium oxide, Kyowa Chemical Co., Ltd. stearic acid: First-grade reagent ZnO: zinc oxide, manufactured by Sakai Chemical Industry Co., Ltd.

[0109]

[Table 2]

[0110]

[Table 3]

From Table 3, Example 2 in which polyamine vulcanization was performed as the vulcanization treatment (2) had lower tensile strength and cut elongation than Comparative Example 2 in which polyamine vulcanization was performed as the first vulcanization. However, it was found that the hardness (storeA) was almost the same.

[0112]

EFFECTS OF THE INVENTION Since the method for producing a regenerated vulcanized fluororubber of the present invention has the above-mentioned structure, the vulcanized fluororubber can be regenerated from the vulcanized fluororubber through revulcanization.
The composition for regenerated unvulcanized fluororubber of the present invention enables such revulcanization, and the obtained regenerated vulcanized fluororubber is the same as the fluororubber obtained by the first vulcanization. It has a wide range of uses.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) C08L 27:12 C08L 27:12 (72) Inventor Tsunayuki Okumura Nishiichitsuya No. 1 Settsu City, Osaka Prefecture Daikin F-Term in Yodogawa Manufacturing Co., Ltd. (reference) 4F203 AA16 AA45 AA50 AB03 AR06 DA11 DC01 DF01 DF02 DK07 4F301 AA05 AB01 BF31 CA04 CA09 CA24 CA41 CA52 CA72

Claims (9)

[Claims] 1. A regenerated vulcanized fluororubber (A) is heated to obtain a regenerated unvulcanized fluororubber (B), and then the regenerated unvulcanized fluororubber (B) is vulcanized ( A method for producing a regenerated vulcanized fluororubber, which comprises obtaining a regenerated vulcanized fluororubber (C) by applying 2), wherein the regenerated vulcanized fluororubber (A) is obtained by vulcanization treatment (1). A method for producing a regenerated vulcanized fluororubber, which is characterized in that 2. The method for producing a regenerated vulcanized fluororubber according to claim 1, wherein the heat treatment is performed at 240 ° C. to 400 ° C. 3. The method for producing a regenerated vulcanized fluororubber according to claim 1, wherein the vulcanization treatment (1) uses a peroxide. 4. A regenerated vulcanized fluororubber (A) is obtained by subjecting a copolymer obtained from a monomer component containing vinylidene fluoride to a vulcanization treatment (1). The method for producing a regenerated vulcanized fluororubber according to claim 1, 2 or 3. 5. The regenerated vulcanizable fluororubber (A) is composed of a copolymer having a site represented by —CFR ¹ —CH ₂ — (R ¹ represents a crosslinking site) in the main chain. The method for producing a regenerated vulcanized fluororubber according to claim 1, 2, 3, or 4. 6. The regenerated unvulcanized fluororubber (B) is made of a crosslinkable fluoropolymer and is vulcanized (2).
Is to react the crosslinkable site of the crosslinkable fluoropolymer, the crosslinkable site,
_{^{(I) -CFR 2 -CH 2 -}} (. R 2 is showing a fluorine atom or a crosslinking site residue) site in the main chain represented by or,
(Ii) It is an ionic group, Claim 1, 2, 3, 4 or 5.
A method for producing the regenerated vulcanized fluororubber described. 7. The vulcanization treatment (2) is a vulcanization method using a polyamine, a vulcanization method using a polyol, and / or
The method for producing a regenerated vulcanized fluororubber according to claim 1, which is a vulcanization method using an ionic group generated by heat treatment. 8. A composition for regenerated unvulcanized fluororubber (B) and a vulcanizing agent, which is used for obtaining regenerated vulcanized fluororubber (C) by vulcanization. And is composed of the above-mentioned unvulcanized fluororubber (B).
Is obtained by heating the regenerated vulcanized fluororubber (A), and the regenerated vulcanized fluororubber (A) is obtained by the vulcanization treatment (1). A characteristic composition for regenerated unvulcanized fluororubber. 9. The composition for regenerated unvulcanized fluororubber according to claim 8, wherein the vulcanizing agent is a polyol, a polyamine and / or a metal oxide.