WO2003064131A1

WO2003064131A1 - Process for production of reclaimed fluororubber vulcanizates and compositions for the devulcanized fluororubbers to be reclaimed

Info

Publication number: WO2003064131A1
Application number: PCT/JP2003/000643
Authority: WO
Inventors: Mitsuhiro Ohtani; Katsusada Tokuhira; Tsunayuki Okumura
Original assignee: Daikin Industries, Ltd.
Priority date: 2002-01-28
Filing date: 2003-01-24
Publication date: 2003-08-07
Also published as: JP2003211460A; JP4449271B2

Abstract

The invention provides a process for producing a reclaimed fluororubber from a waste fluororubber vulcanizate through revulcanization; a composition for the above revulcanization; and reclaimed fluororubber vulcanizates. A process for production of reclaimed fluororubber vulcanizates which comprises converting a waste fluororubber vulcanizate (A) into a devulcanized fluororubber (B) by thermal treatment and then subjecting the devulcanized fluororubber (B) to vulcanization (2) to form a reclaimed fluororubber vulcanizate (C), characterized in that the waste fluororubber vulcanizate (A) is one obtained by vulcanization (1).

Description

Method for producing recycled vulcanized fluoro rubber and composition for recycled unvulcanized fluoro rubber

The present invention relates to a method for producing a reclaimed fluorine rubber from a vulcanized fluorine rubber to be regenerated, through re-vulcanization, and a composition for a reclaimed unvulcanized fluoro rubber used for re-vulcanization. Background art

Fluororubber has excellent properties such as heat resistance, chemical resistance, and oil resistance, so it is used in applications where severe use conditions such as exposure to various chemicals and high temperatures are imposed, such as the automotive industry, aircraft industry, and semiconductors. Even in applications such as industry, it is used as a material for various parts.

Fluororubber is usually used as a molded product after vulcanization, so it may be necessary to treat debris, defective products, used molded products, etc. at the same time as general molded products. . However, vulcanized fluoro rubber has its excellent properties, which hinders chemical treatment, and because it produces corrosive decomposition products when burned, thermal recycling is not easy. Was.

In recent years, with the increasing awareness of environmental protection and effective use of resources by reducing the amount of landfills, etc., there has been a growing demand for the development of methods for reusing previously discarded fluororubber.

Conventionally, it is difficult to recycle vulcanized fluororubber as a fluororubber because it is difficult to regenerate it as it is not suitable for chemical treatment or combustion. Has only been put to practical use. As a method used as a filler, there was a method in which vulcanized fluoro rubber was mechanically pulverized by freeze pulverization or the like.

Japanese Patent Application Laid-Open No. 61-68905 discloses that vulcanized fluororubber is heat-treated in the presence of oxygen and added to unvulcanized fluororubber to improve the processability during molding. Methods have been proposed to improve this. In this method, peroxide vulcanized fluorine Rubber is preferably used, but it is described that this gives an excellent product.Uncured fluororubber to which heat-treated fluororubber has been added is subjected to peroxide vulcanization in Examples. Therefore, it is considered to be used as a filler. As described above, conventionally, the only method of reusing vulcanized fluororubber is to use it as a filler to be added to the fluororubber composition, and there has been a problem that the way of reusing is extremely limited. In order to expand the recycling process and promote resource utilization, it has been desired to develop a method for regenerating fluororubber from vulcanized fluororubber through re-vulcanization. Summary of the Invention

In view of the above situation, an object of the present invention is to provide a method for producing a reclaimed fluororubber from a vulcanized fluororubber to be regenerated, through re-vulcanization, and a composition for the above revulcanization. It is in.

In the present invention, after the regenerated vulcanized fluororubber (A) is subjected to a heat treatment to obtain a regenerated unvulcanized fluororubber (B), the regenerated unvulcanized fluororubber (B) is vulcanized ( 2) A method of producing a reclaimed vulcanized fluororubber (C) by obtaining a reclaimed vulcanized fluororubber (C) by subjecting the reclaimed vulcanized fluororubber (A) to a vulcanization treatment (1). A method for producing a reclaimed vulcanized fluororubber, characterized by being obtained by the above method.

The present invention relates to a composition for reclaimed unvulcanized fluororubber used for obtaining a reclaimed vulcanized fluororubber (C) by vulcanization, comprising a reclaimed unvulcanized fluororubber (B) and a vulcanizing agent Wherein the regenerated unvulcanized fluororubber (B) is obtained by heat-treating the regenerated vulcanized fluororubber (A), and the regenerated vulcanized fluororubber (A) ) Is a composition for a regenerated unvulcanized fluororubber, which is obtained by the vulcanization treatment (1). Detailed Disclosure of the Invention

Hereinafter, the present invention will be described in detail.

The method for producing a reclaimed vulcanized fluororubber of the present invention comprises the steps of: heating a reclaimed vulcanized fluororubber (A) to obtain a reclaimed unvulcanized fluororubber (B); By subjecting (B) to vulcanization (2), a reclaimed vulcanized fluororubber (C) is obtained.

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

In the present specification, the above-mentioned “regenerated unvulcanized fluororubber (B)” is obtained by subjecting the regenerated vulcanized fluororubber (A) to a heat treatment in the method for producing a regenerated vulcanized fluororubber of the present invention. Means unvulcanized fluoro rubber. In the present specification, “unvulcanized fluoro rubber” means fluoro rubber which is in a substantially unvulcanized state.

In the present specification, the above-mentioned “reclaimed vulcanized fluororubber (C)” is a reclaimed product obtained by reclaiming in the method for producing a reclaimed vulcanized fluororubber of the present invention. B) means a vulcanized fluoro rubber obtained by re-vulcanizing. The vulcanized fluoro rubber for the regenerated vulcanized fluoro rubber (C) is the same as the vulcanized fluoro rubber described for the regenerated vulcanized fluoro rubber (A).

In the method for producing a reclaimed vulcanized fluororubber of the present invention comprising obtaining the reclaimed vulcanized fluororubber (C) from the reclaimed vulcanized fluororubber (A), the reclaimed unvulcanized fluororubber (B ) Is, as it were, an intermediate obtained in the process of obtaining a regenerated vulcanized fluororubber (C), which is a regenerated product obtained by regenerating from the regenerated vulcanized fluororubber (A). I can say.

In the present specification, as described above, the “vulcanized fluororubber” means a fluororubber in a vulcanized state, and is not particularly limited as long as it is a fluororubber in such a state. For example, it may be a non-vulcanized fluoro rubber or a fluoro rubber obtained by subjecting an unvulcanized fluoro rubber thread to a vulcanization treatment. It may refer to both the fluororubber, that is, both the above-mentioned regenerated vulcanized fluororubber (A) and the above-mentioned regenerated vulcanized fluororubber (C). It is a term generally used for vulcanized fluoro rubber other than vulcanized fluoro rubber in the method for producing a reclaimed vulcanized fluoro rubber of the present invention.

The unvulcanized fluororubber composition is usually composed of an elastomeric fluoropolymer and a vulcanizing additive usually used for rubber vulcanization, and is subjected to vulcanization. Not what it is. The additive for vulcanization depends on the vulcanization method used, such as polyol vulcanization or noxide vulcanization, but generally includes vulcanizing agents, vulcanization accelerators, and acid acceptors. The components other than the vulcanizing agent are usually optional components that are optionally used for accelerating vulcanization and the like.

In the present specification, the “elastomer-containing fluoropolymer” 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 refers to those that have elastomeric properties such as fluorosulfur rubber.

The vulcanized fluororubber is made of a molecule in which a crosslinking site is bonded to a carbon chain derived from the elastomeric fluoropolymer. In the present specification, such a molecule is sometimes referred to as a cross-linking molecule. In the present specification, the “crosslinking site” is a site that is chemically bonded to the elastomeric fluoropolymer by vulcanization, and is derived from the vulcanizing agent used in the vulcanization. Which 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 may be one of the elastomeric fluoropolymers. A bond may be formed between a site in a molecule and a site in another molecule. In the present specification, such a site where the above-described cross-linking site is bonded in the molecule of the elastomeric fluoropolymer may be referred to as a “cross-linking point”.

The unvulcanized fluoro rubber is made of a crosslinkable fluoropolymer. The crosslinkable fluoropolymer comprises a carbon chain derived from the elastomeric fluoropolymer, and a small amount of the crosslinking site may be bonded to the carbon chain. Usually, such a small amount of the crosslinked portion is a crosslinked portion which remains without being decomposed when the regenerated vulcanized fluororubber (A) is subjected to heat treatment in the method for producing a regenerated vulcanized fluororubber of the present invention. Rank. It is considered that a small amount of crosslinked sites usually remain due to the above heat treatment. Since the carbon chains derived from the elastomeric fluoropolymer are not usually cut by the heat treatment, the carbon chains originate from the elastomeric fluoropolymer in the crosslinked molecules forming the regenerated vulcanized fluororubber (A). Substantially the same as the carbon chain. The unvulcanized fluoro rubber is different from the vulcanized fluoro rubber in that it has a processable viscosity. As the processable viscosity, it is usually preferable to have a Mooney viscosity (ML _{1 +10} , 100 ° C.) of 5 to 200.

In the present specification, when simply referred to as “elastomeric fluoropolymer”, the above-mentioned crosslinking site is not bonded. Such an elastomeric fluorine-containing polymer is a fluorine-containing polymer that has been obtained by polymerization to have elastomeric properties and has not been subjected to vulcanization treatment. It may be compounded in a rubber composition. The elastomeric fluorine-containing polymer is distinguished from the crosslinked molecules forming the vulcanized fluororubber in that it has not been vulcanized and has no crosslinked portion bonded thereto. It is also distinguished from a crosslinkable fluoropolymer that forms a fluororubber, that is, one in which a small number of crosslinkable sites are bonded to a carbon chain derived from an elastomeric fluoropolymer.

The recycled vulcanized fluoro rubber (C) is obtained by re-vulcanizing as described above. In the present specification, the “re-vulcanization” means vulcanizing the unvulcanized fluoro rubber. That is, the re-vulcanization is performed on an unvulcanized fluoro rubber made of a crosslinkable fluoropolymer. In the re-vulcanization, at least a part of the cross-linking site is decomposed by the heat treatment in the post-process of the cross-linkable fluoropolymer, but the vulcanization treatment is applied. This is distinguished from the so-called first vulcanization performed on an unvulcanized fluororubber composition comprising an elastomeric fluoropolymer having no cross-linking site bonded thereto.

The vulcanization method in the re-vulcanization may be the same as the first vulcanization method, or may be different. Both the re-vulcanization and the first vulcanization involve primary vulcanization, or primary vulcanization and secondary vulcanization, in the same manner as ordinary vulcanization. In the method for producing a reclaimed vulcanized fluororubber of the present invention, the first vulcanization treatment is referred to as vulcanization treatment (1), and the re-vulcanization treatment is referred to as vulcanization treatment (2). The above-mentioned recycled vulcanized fluororubber (C) is obtained by the first vulcanization described above in that it is obtained by re-vulcanization. Although distinguished from the above, as in the case where the vulcanization treatment method is the same, as a result, they may be composed of the same molecule, composition and the like.

The present inventors heat-treated the regenerated vulcanized fluororubber (A) comprising a cross-linked molecule in which the above-mentioned bridging site is bonded to a carbon chain derived from the above-mentioned elastomeric fluoropolymer, whereby the above-mentioned elastomer is obtained. The bond at the cross-linking site can be cut before cutting the carbon chain derived from the unifunctional fluoropolymer, and the state obtained by the heat treatment can be re-vulcanized. It has been found that by performing the above-mentioned heat treatment and the above-mentioned re-vulcanization, it is possible to regenerate the fluoro-rubber through re-carosulfuration even if the fluoro-rubber is once vulcanized. Completed the method.

The method for producing a reclaimed vulcanized fluororubber of the present invention comprises first heating the reclaimed vulcanized fluororubber (A) to obtain a reclaimed unvulcanized fluororubber (B). The vulcanized fluoro rubber (A) is obtained by the vulcanization treatment (1). The vulcanization treatment (1) is performed on an unvulcanized fluororubber composition. As described above, the unvulcanized fluororubber composition comprises an elastomeric fluoropolymer and a vulcanizing additive.

Examples of the vulcanization of the fluororubber include those using a peroxide, those using a polyol, those using a polyamine, and the like. In order to efficiently perform selective cutting at the cut portion in the heat treatment of the fluororubber (A), it is preferable to use peroxide. In the present specification, vulcanization using peroxide may be referred to as peroxide vulcanization.

In vulcanization using peroxide, usually, radicals generated from peroxide are added to a polyfunctional unsaturated compound to be blended substantially as a vulcanizing agent to generate another radical, and the latter radical is elastomeric fluorine-containing. A bridge is formed by a chain reaction including a reaction to be added to a polymer. The above polyfunctional unsaturated compound is referred to as a vulcanization aid, vulcanization accelerator or co-vulcanization agent in peroxide vulcanization. There is. The mechanism of such peroxide vulcanization will be described below, taking as an example the case where dialkyl peroxide is used as the peroxide and triaryl cyanurate is used as the polyfunctional unsaturated compound.

A crosslinked molecule obtained by vulcanization using a peroxide usually has a chemical structure derived from the vulcanization aid used at a crosslinked site. Cleavage of the bond at such a crosslinking site can be performed at a lower temperature than cleavage of the carbon-carbon bond in the carbon chain derived from the elastomeric fluoropolymer in the crosslinked molecule. The heat treatment in the method for producing a recycled 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 crosslinked site in the obtained crosslinked molecule has a chemical structure derived from TAIC. In the chemical structure derived from TAIC, a carbon chain derived from the aryl group of TAIC is bonded to the nitrogen constituting the saturated 6-membered ring. This carbon chain is usually saturated with a bridge and is an n-propylene group. It is considered that the heat treatment breaks the bond between the nitrogen and the adjacent carbon or the bond between the adjacent carbon and the adjacent carbon among the bonds in the n-propylene group. Can be

TAIC is considered to have the highest heat resistance among the vulcanization aids that can be used for peroxide vulcanization, and is obtained when peroxide vulcanization is performed using a vulcanization aid other than TAIC. Since the cross-linking site in the cross-linking molecule breaks the bond at a lower temperature than the chemical structure derived from TAIC, the difference in the above-mentioned cleavage temperature is large, and the selective cleavage of the bond at the cross-linking site is even more than when TAIC is used. It is considered easy. Therefore, as the vulcanization treatment (1), peroxide vulcanization is preferable, not limited to the case of using TAIC.

When peroxide vulcanization is performed as the vulcanization treatment (1), the reaction of the above vulcanization treatment (1) is likely to proceed due to a chain reaction with radicals, and it is considered that there is no residual vulcanizing agent or the amount is small. Therefore, in the heat treatment, the cross-linking reaction substantially no longer occurs. The use of peroxide vulcanization as the vulcanization treatment (1) is also preferable from the viewpoint that a crosslinked site can be cut without a crosslinking reaction in the above heat treatment.

The cross-linked molecule obtained by vulcanization using a polyol and the cross-linked molecule obtained by vulcanization using a polyamine generally have a bond breaking force at a cross-linking site, a carbon chain derived from an elastomeric fluoropolymer. Of the carbon-carbon bond at What happens at lower temperatures than cutting is similar to peroxide vulcanization. However, when a polyol or polyamine is used in the vulcanization treatment (1), it remains without reacting after the vulcanization treatment (1) during the heat treatment, in parallel with the cleavage of the bond at the cross-linking site. Vulcanization proceeds with the vulcanizing 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 again as a fluororubber. The peroxide used for the peroxide vulcanization is not particularly limited. However, an organic peroxide is preferred because it can easily generate a peroxide radical in the presence of heat or an oxidation-reduction system. The organic peroxide, that is, the organic peroxide, is not particularly limited. For example, 1,1-bis (t-butylperoxy) -1,3,5,5-trimethylcyclohexane, 2,5_ Dimethylhexane 1,2,5-dihydroperoxide, di-t-butylperoxide, t-butylcumyl peroxide, dicumyl peroxide, 2,5-dimethyl-2,5-bis ( (t-butyl peroxy) hexane, α, bi-bis (t-butyl peroxy) 1-p-diisobutylpyrubenzene, 2,5-dimethyl-1,2,5-di (t-butyl peroxy) 1-hexyl 3-benzoyl peroxy Xide, t-butynoleoxybenzene, t-butynoleoxybenzoate, 2,5-dimethyl-1,2,5-di (benzoinoleoxy) 1-hexane, t-butyl peroxymale Acid, t chromatography butyrate Honoré Per O key Consequences isopropyl carbonate. Among them, a dialkyl-based organic peroxide having two alkyl groups is preferable, and 2,5-dimethyl-1,2,5-di (t-butylperoxy) hexane is more preferable. Further, t-butyl peroxybenzoate is also preferable.

The amount of the above-mentioned organic peroxide to be used is appropriately determined in consideration of the amount of the active group of the dioxy group or the epidioxy group represented by the formula 1-O-1 in the organic peroxide, the decomposition temperature, and the like. Usually, the amount is preferably 0.05 to 10 parts by weight, and more preferably 1.0 part by weight, more preferably 1.0 part by weight, based on 100 parts by weight of the elastomeric fluoropolymer. The upper limit is 5 parts by weight.

In the peroxide vulcanization with the above-mentioned organic peroxide, the vulcanization is remarkably promoted by using a vulcanization aid. The vulcanization aid is not particularly limited, for example, Examples thereof include those conventionally used. Examples of such compounds include triazine derivatives such as triaryl cyanurate and triallyl isocyanurate; triaryl trimellitate, Ν, Ν′—m— Aromatic ring-containing compounds such as phenylene bismaleimide, dipropargyl terephthalate, diaryl phthalate, tetraaryl terephthalate amide; and acyclic compounds such as triacryl formal and triallyl phosphate. From the viewpoint of versatility and the like, a triazine derivative is preferable, and triallyl isocyanurate is more preferable. The amount of the vulcanization aid is usually 0.1 to 10 parts by weight, preferably 0.1 to 10 parts by weight, and more preferably 0.5 to 10 parts by weight, based on 100 parts by weight of the elastomeric fluoropolymer. Is 5 parts by weight, preferably 0.5 to 5 parts by weight.

The method of peroxide vulcanization is not particularly limited.For example, a roll vulcanization may be performed using an unvulcanized fluoro rubber composition comprising an elastomeric fluoropolymer and an additive for vulcanization by a method similar to the conventional method. And vulcanization, followed by primary vulcanization under pressure and, if desired, secondary vulcanization. In general, the primary vulcanization conditions are temperature 100 to 200, time 5 to 60 minutes, pressure 2 to: range of about LOMPa. It is adopted in the range of about 30 minutes to 30 hours at 50 to 300 ° C. As the vulcanizing additive, besides the vulcanizing agent, a vulcanization accelerator may be used as needed, and other additives which can be appropriately mixed may be used. The reclaimed vulcanized fluororubber (A) is obtained by the vulcanization treatment (1), and is made of carbon derived from the elastomeric fluoropolymer in the above-mentioned unstripped fluororubber composition. It consists of a cross-linking molecule formed by linking a cross-linking site to a chain. The reclaimed vulcanized fluororubber (A) is not particularly limited as long as it is such a substance. However, since it is easy to crosslink, it is added to a copolymer obtained from a monomer component containing vinylidene fluoride. It is preferable that the reclaimed vulcanized fluororubber (A) is, for example, one obtained by subjecting the main chain to one CFR ¹ — CH _2- ( R ¹ represents a cross-linking site, which can be said to consist of a copolymer having a site represented by: In the main chain of the copolymer constituting the regenerated vulcanized fluororubber (A), 1,1-difluoroethylene groups remain. The copolymer obtained from the monomer component containing vinylidene fluoride is the above-mentioned elastomer-type fluorinated polymer. Body.

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

The elastomeric fluoropolymer is preferably a copolymer obtained from vinylidene fluoride and a monomer component containing perfluoroolefin and / or perfluorobutyl ether. One or more of perfluoroolefin and / or perfluorobiel ether can be used, respectively. As the elastomeric fluoropolymer, a copolymer obtained from a monomer component containing vinylidene fluoride and perfluoroolefin is more preferable.

Examples of the above perfluorophenol include olefins such as ethylene tetrahexenole and propylene hexanol. As the above perfluorobutyl ether, perfluoro (alkyl vinyl ether) having 1 to 6 carbon atoms in a perfluoroalkyl group, represented by the following general formula:

CF ₂ = CFO (CF ₂ CFX ¹ 0) _n i- (CF ₂ CF ₂ CF ₂ 0) _n2 -R f ¹

(In the formula, X ¹ represents a fluorine atom or a trifluoromethyl group, and represents a fluoropolyoxyalkyl group having 20 to 20 carbon atoms or a perfluoroalkyl group having 1 to 8 carbon atoms.) , N1 and n2 are the same or different and each represent an integer of 0 to 5, provided that nl + n2 ≥ 1.) and the like. The elastomeric fluorine-containing polymer may be used in addition to vinylidene fluoride, perfluoroolefin and Z or perfluorovinyl ether, and a monomer having a crosslinking group may be used as the monomer component of the elastomeric fluorine-containing polymer. It is preferable to polymerize at a rate of 0.1 to 3 mol%. In the present specification, the “crosslinkable group-containing monomer” means an ethylenically unsaturated compound having at least one iodine atom, Z or bromine atom as a crosslinkable group in a molecule.

Elastomer-containing rubber obtained from a monomer component containing the above-mentioned crosslinkable group-containing monomer The nitrogen polymer has iodine and / or bromine bonded to the carbon constituting the main chain and / or the carbon constituting the side chain. As described above, iodine and / or bromine provide a radical active point when peroxide vulcanization is performed as the vulcanization treatment (1). That is, in such an elastomeric fluorine-containing polymer, iodine, Z or bromine is easily eliminated by radicals generated from the peroxide in the peroxide vulcanization and has unpaired electrons, and this unpaired electron is added. It forms a bond by adding to the unsaturated bond of the sulfur aid, and forms a bridge efficiently. If the elastomeric fluoropolymer has no iodine and no bromine, it has high resistance to attack by radicals, so that peroxide vulcanization hardly proceeds. In the present specification, the above-mentioned "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 [ B r] does not exist.

When the elastomeric fluoropolymer is obtained from a monomer component containing the crosslinkable group-containing monomer, it is obtained by polymerizing vinylidene fluoride and perfluoroolefin and Z or perfluorovinyl ether. Where A is the segment obtained by

X ^2- [A-(Y) _{n 3} ] _{n 4} -X ³

(In the formula, X ² and X ³ are the same or different and represent a group derived from a polymerization initiator or a chain transfer agent or a group obtained by modification after polymerization. Y represents a carbon atom having iodine and / or bromine. N 3 represents an integer of 0 to 50, and n 4 represents an integer of 1 to 5, provided that n 3 X n 4 ≥ l. N 4 [A— (Y) _{n 3} ] may be the same or different, and if different, 114, n 4 Y and n And the four n 3 's may be the same or different.) It is preferable that they have a chemical structure represented by the following formula:

Y in the above formula may be introduced by any of block copolymerization, graft copolymerization, alternating copolymerization, and random copolymerization. X ² and X ³ can be arbitrarily changed by selecting the type and amount of the polymerization initiator and / or chain transfer agent used during the polymerization of the elastomeric fluoropolymer, and It can also be changed arbitrarily by modifying the terminal group obtained by polymerization. X ² And X ³ is preferably a propyloxyl group, an alkoxycarbonyl group, a nitrile group, an iodine atom, a bromine atom or a sulfonic acid group.

Examples of the crosslinking group-containing monomer include the following general formula I (CH ₂ CF ₂ CF ₂₀ ) _n 5- (CFCF ₂ O) _n6 CF = CF ₂

CF ₃

(In the formula, n5 represents an integer of 1 to 5, and n6 represents an integer of 0 to 3.)

And iodine-containing fluorinated butyl ether.

Preferred examples of the iodine-containing fluorinated butyl ether include:

I CH ₂ CF ₂ CF ₂ OCF = CF ₂ ,

I (CH ₂ CF ₂ CF ₂ 0) ₂ CF = CF ₂ ,

I (CH ₂ CF ₂ CF ₂ 0) ₃ CF = CF ₂ ,

I CH ₂ CF ₂ CF ₂ OCF (CF ₃ ) CF ₂ OCF = CF ₂ ,

I CH ₂ CF ₂ CF ₂ 0 [CF (CF ₃ ) CF ₂ 0] ₂ CF = CF ₂

And the like,

I CH ₂ CF ₂ CF ₂ OCF = CF ₂

Is more preferred.

The elastomeric fluoropolymer can be produced by, for example, a conventionally known method. For example, a polymerization method such as emulsion polymerization or suspension polymerization can be used. The crosslinked molecule in the regenerated vulcanized fluororubber (A) is a crosslinked molecule bonded to a carbon chain derived from the elastomeric fluoropolymer, and is obtained by the vulcanization treatment (1). It is a thing. Accordingly, the carbon chain may have a difference in chemical structure from the elastomeric fluoropolymer in addition to having a cross-linking point where a cross-linking site is bonded. For example, in the case where peroxide is used in the vulcanization treatment (1), the carbon chain contains iodine contained in the elastomeric fluoropolymer as apparent from the mechanism described above for peroxide vulcanization. And / or does not have bromine in the molecule.

In the method for producing a reclaimed vulcanized fluororubber according to the present invention, In (A), heat treatment is then performed.

The heat treatment is preferably performed at 240 to 400 ° C. According to thermogravimetry (TG measurement), the decomposition temperature of fluororubber is usually a temperature exceeding 400 ° C. It is considered that the carbon chain derived from the above-mentioned elastomeric fluoropolymer in the crosslinked molecule forming the rubber (A) is cleaved. On the other hand, the crosslinked site of the fluororubber obtained by peroxide vulcanization is usually decomposed at a temperature of 240 ° C or higher. Accordingly, by performing the heat treatment at a temperature lower than the carbon chain cleavage start temperature and higher than the crosslink site cleavage start temperature, that is, 240 to 400 ° C., the regenerated vulcanized fluororubber (A) In the cross-linking molecule, the above-mentioned cross-linking site alone can be selectively decomposed without substantially cutting the carbon chain derived from the elastomeric fluoropolymer.

The heating conditions for the heat treatment depend on the type and degree of vulcanization of the regenerated vulcanized fluororubber (A). However, from the point that the crosslinked portion can be sufficiently cut, the heating time is further determined by using a heating device, Depending on the processing conditions such as heating temperature and pressurizing pressure, etc., it cannot be said unconditionally. When heating at 300 ° C, for example, the above-mentioned cross-linking site can be sufficiently cut in 168 hours or less, and usually no heating is performed. 24 to 100 hours under pressure.

The heat treatment is preferably performed in air (under an oxygen-containing atmosphere) because it is easily decomposed.

In the method for producing a reclaimed vulcanized fluororubber of the present invention, a reclaimed unvulcanized fluororubber (B) is obtained by subjecting the reclaimed vulcanized fluororubber (A) to a heat treatment. As described above for the unvulcanized fluoro rubber, the unvulcanized fluoro rubber to be regenerated is made of a crosslinkable fluoropolymer and has a workable viscosity.

As described above, the crosslinkable fluoropolymer comprises a carbon chain derived from the elastomeric fluoropolymer. Since this carbon chain is derived from the crosslinked molecule in the regenerated vulcanized fluororubber (A), for example, when peroxide is used in the vulcanization treatment (1), as in the case of the crosslinked molecule, it contains an elastomeric material. It has no iodine and no bromine that the fluoropolymer had. The crosslinkable fluoropolymer may be one in which a small amount of a crosslinkable site is bonded to a carbon chain derived from the elastomeric fluoropolymer. The cross-linking site is generally bonded to the carbon chain in a small amount as a result of the above-described heat treatment. However, even when the decomposition is sufficiently performed by the above-described heat treatment, the cross-linked portion is not bonded. Good. The cross-linking site bonded to the carbon chain forms a bridge. Accordingly, the cross-linking site in the cross-linking molecule forming the regenerated vulcanized fluororubber (A) is broken by the heat treatment to become a part, and is not crosslinked, but carbon derived from the elastomeric fluoropolymer is not crosslinked. Those still bonded on the chain (hereinafter referred to as “crosslinking site residues”) are not included in the “crosslinking site bonded to the carbon chain”. Can be said to be in a state not bonded to the carbon chain.

At the cross-linking site of the cross-linking molecule that forms the regenerated vulcanized fluororubber (A), the portion at which the bond was broken by the heat treatment was at least when peroxide was used in the vulcanization treatment (1). In particular, when triallyl isocyanurate is used as a vulcanization aid, the chain ends become unstable due to cleavage, and because of the instability, usually stabilizes naturally to become a carboxyl group. Therefore, in this case, the crosslinkable fluorine-containing polymer has a carboxyl group in the side chain. This side chain is composed of a part of the chemical structure derived from the crosslinking site. The side chain having a carboxyl group is one of the above-mentioned cross-linking site residues.

The unvulcanized rubber to be regenerated (B) is distinguished by the fact that the vulcanized rubber to be regenerated (A) is insoluble in polar solvents such as acetone and tetrahydrofuran, but soluble in the polar solvent. can do.

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

The mechanism of vulcanization in the vulcanization treatment (2) is not particularly limited. And those obtained by reacting the crosslinkable sites of the fluorinated polymer. The crosslinkable site is (i) a site in the main chain represented by one CFR ² —CH ₂ — (R ² represents a fluorine atom or a bridge site residue), or (ii) an ionic group. It is. The 1,1-difluoroethylene group in which R ² is a fluorine atom in the formula (i) is usually preferably contained in the monomer component of the elastomeric fluorine-containing polymer. It is a divalent group derived from vinylidene fluoride. The crosslinking site residue as R ² in the above formula (i) is as described above as being a part of the crosslinking site cleaved by the heat treatment. The ionic group is formed as a result of a bond at a cross-linking site being cut by heat treatment of the regenerated vulcanized fluororubber (A), and examples thereof include the above-mentioned carboxyl group. As the crosslinkable site, the site (i) is preferable from the viewpoint of high crosslinkability, and the 1,1 difluoroethylene group is preferable as the site (i).

Examples of the vulcanization method comprising reacting the above-mentioned site (i) include a vulcanization method using a polyol and a vulcanization method using a polyamine. In this specification, the vulcanization method using a polyol may be referred to as polyol vulcanization, and the vulcanization method using a polyamine may be referred to as polyamine vulcanization.

Polyol vulcanization used for vulcanization treatment (2) is generally carried out using a nucleophilic agent obtained by reacting calcium hydroxide with an osmium compound used as a vulcanization accelerator, for example, a 1,1-difluoroethylene group. The compound is dehydrofluorinated from the site (i) described above, and a polyol compound used as a vulcanizing agent is added to the resulting double bond to form a crosslink, thereby causing crosslinking. The generated hydrogen fluoride can be eliminated by reacting with the magnesium oxide used as the acid acceptor. As the polyol compound used in the vulcanization of the polyol used in the vulcanization treatment (2), for example, a polyol compound generally known as a vulcanizing agent for a 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 because a fluororubber excellent in heat resistance, mechanical strength, and the like is easily obtained. Examples of the polyhydroxy aromatic compound include 2,2-bis (4-hydroxyphenyl) propane [bisphenol A] and 2,2-bis (4-hydroxyoxy). Feninole) Perphnoleo-propane [bisphenol AF], resorcinol, 1,3-trihydroxybenzene, 1,7-dihydroxynaphthalene, 2,7-dihydroxynaphthalene, 1,6-dihydrido Xinaphthalene, 4,4'-dihydroxy-dipheninole, 4,4-dihydroxy-stinoleben, 2,6-dihydroxy-xylene-racene, hydroquinone, catechol, 2,2-bis (4-hydroxy-doxypheninole) butane [Bisphenol II], 4,4-bis (4-hydroxyphenyl) valeric acid, 2,2-bis (4-hydroxyphenyl) tetrafluorodichloropropane, 4,4'-jihidroxydiphenylinoresole Hong, 4, '-dihydroxydipheninoletone, tri (4-hydroxyphenyl) methane, 3,3', 5,5'-tetrak Le Α, 3, 3 ', 5 , 5 7 - tetra Promo bisphenol Alpha, and the like. These polyhydroxy aromatic compounds may be an alkali metal salt or an alkaline earth metal salt, etc., but the acid coagulates the coagulated cross-linking molecules that will form the resulting reclaimed vulcanized fluororubber (C). It is preferable not to use these metal salts when the reaction is carried out by using.

As the vulcanization accelerator used for the vulcanization of the polyol used as the vulcanization treatment (2), for example, an iridium compound generally known as a vulcanization accelerator for the polyol vulcanization of a fluororubber can be used. . Examples of such an ammonium compound include an ammonium compound such as a quaternary ammonium salt, a phosphonium compound such as a quaternary phosphonium salt, an oxonium compound, a sulfonium compound, and the like. Ammonium salts and quaternary phosphonium salts are preferred. Examples of quaternary ammonium salts include, for example, 8-methyl-1,8-diazabicyclo mouth [5.4.0] — 7-indesenium chloride, 8-methyl-1,8-diazabicyclo [5 4.00] 1-7-dedecenium iodide, 8-methyl-1,8-diazabicyclo [5.4.0] — 7-dedecenium hydroxide, 8-methyl-1 , 8 dia. Mouth [5. 4. 0] 1- 7-dimethyl sulphate methyl sulfate, 8-ethyl chloro 1, 8-dia. 1-mouth [5. 4. 0]-7 _ , 8-propyl_1,8-diazabicyclo [5.4.0] — 7-indesenium bromide, 8-dodecyl-1,8-diazabicyclo [5.4.0] Dedecenium chloride, 8-dodecyl 1,8-di Azabishikuro [5. 4.0] one 7-© down de Seni ©-time hydro-described de, 8-E Ikoshiru 1, 8 one Jiazabishikuro _[5. 4.0] -7-© down de Seni © skeleton Li De, 8 —Tetracosyl-1,8-diazabicyclo [5.4.0] -17-didecenium chloride, 8-benzyl-1,8-diazabicyclo [5.4.0] _7-indesenii Muchloride, 8-benzinole-1,8-diazabicyclo [5.4.0] _ 7-indesenium hydroxide, 8-phenetinole 1,8-diazabicyclo [5. 4. 0] — 7-indesenium chloride, 8- (3-phenylpropyl) 1,8-diaza-bis [5.4.0] 1-7-indesenium chloride, etc.

Examples of the quaternary phosphonium salts include tetrabutylphosphonium chloride, benzinoletriphenylenolephosphonium chloride, benzinoletrimethinolephosphonium chloride, and benzyltriptylphosphonium chloride. No.

The polyol compound used in the polyol vulcanization is usually 0.5 to 5 parts by weight, preferably 1 part by weight, and preferably 2 parts by weight, per 100 parts by weight of the crosslinkable fluoropolymer. And preferably 1 to 2 parts by weight.

The vulcanization accelerator used in the polyol vulcanization is usually 0.2 to 10 parts by weight, preferably 0.5 part by weight, and preferably upper limit, per 100 parts by weight of the crosslinkable fluoropolymer. 5 parts by weight, preferably 0.5 to 5 parts by weight.

The vulcanization of the polyol used as the vulcanization treatment (2) can be carried out in the same manner as in the prior art. For example, the crosslinkable fluoropolymer and the above vulcanizing agent, if necessary, a vulcanization accelerator, and After kneading the mixture with other additives that can be mixed, the mixture is put into a mold, pressurized to perform primary vulcanization, and then to secondary vulcanization. In general, the primary vulcanization conditions are a temperature of 100 to 200 ° C, a time of 10 to 180 minutes, and a pressure of about 2 to 10 MPa. The secondary vulcanization conditions are a temperature of 150 to 150 MPa. At 300 ° C, time is adopted from the range of about 30 minutes to 30 hours.

In general, the polyamine vulcanization used as the vulcanization treatment (2) is obtained by dehydrofluorination from the above-mentioned (i) site such as a 1,1-difluoroethylene group which is a crosslinkable site. The polyamine compound used as a vulcanizing agent is added to the resulting double bond to form a bridge, and further dehydrofluorination at the cross-linking point to form a carbon-nitrogen double bond. By doing so, they are crosslinked. The generated hydrogen fluoride can be eliminated by reacting it with magnesium oxide used as an acid acceptor.

Polyamine used for vulcanization treatment (2) The polyamine compound used for vulcanization is a primary or secondary amine having two or more basic nitrogen atoms bonded in the molecule, and in many cases, these are salts. Use with reduced reactivity. Examples of the above-mentioned polyamine compounds include alkylenediamines such as ethylenediaminecarbamate, hexanemethylenediaminecarbamate, and 4,4-diaminecyclohexylmethanecarbamate; N, N, dicinnamylidene-1 And 6-hexamethylenediamine and the like. In addition, a poorly basic aromatic polyamine compound can be used as a vulcanizing agent by using it together with another basic compound. Examples of the other basic compounds include diphenyldananidin, di-O-triguanidine, diphenylthioperia, 2-mercaptoimidazoline, and the like.Also, it is a vulcanization accelerator for synthetic rubber and has an amino group in the molecule. compounds having a group [one NH _2] and Z or an imino group [one NH-], 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 to be regenerated (B).

Vulcanization Treatment (2) A vulcanization method comprising reacting an ionic group such as a carboxyl group of (ii), that is, a vulcanization method utilizing an ionic group includes, for example, metal oxides. And the like. Such vulcanization may be referred to as 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 acts on the lipoxyl group, for example, an ion cluster is formed between two carboxyl groups and a metal atom such as zinc. It is thought that by forming it, it will be a bridge.

The metal oxide used in the ion crosslinking is preferably 0.5 to 50 parts by weight per 100 parts by weight of the unvulcanized fluororubber (B) to be regenerated. 'For the above ion bridge, a method generally used for vulcanizing rubber can be used. The ionic cross-linking is generally performed by adding a small amount of a fatty acid such as stearic acid. As described above, the vulcanization in the vulcanization treatment (2) is such that the crosslinkable fluorinated polymer forming the uncured fluorinated rubber (B) to be regenerated has an elastomeric fluorinated content containing iodine and bromine. Even if it is derived from a polymer, peroxide curing is not suitable because vulcanization treatment (1) does not contain iodine and does not contain bromine, so it is not easily attacked by radicals. Incidentally, the peroxide-cured fluororubber disclosed in the above-mentioned Japanese Patent Application Laid-Open No. 61-69805 similarly does not have iodine in the molecule but has bromine. Instead, it is considered that the peroxide vulcanization after the heat treatment does not cause vulcanization, so it is considered that the heat-treated fluororubber is used as a filler.

In performing the vulcanization treatment (2), the unvulcanized fluoro rubber (B) to be regenerated may be a blend of unvulcanized fluoro rubber. The unvulcanized fluororubber is not particularly limited as long as it can be vulcanized by vulcanization treatment (2), and is selected according to the vulcanization method to be used. When vulcanization with polyol or polyamine is performed as the vulcanization treatment (2), a fluoropolymer having a 1,1-difluoroethylene group is preferable. When ionic cross-linking is performed, for example, a carboxyl group A fluorine-containing polymer obtained from a monomer component containing an ethylenically unsaturated compound having the following can be used.

In the vulcanization treatment (2), molding is usually performed at the same time so that the obtained regenerated vulcanized fluororubber (C) has a desired shape. The molding method is not particularly limited, and includes, for example, known methods such as a method of heating and compressing using a mold, a method of press-fitting into a heated mold, and a method of extruding and steam heating with an extruder. . The above molding is usually performed in primary vulcanization.

In the vulcanization treatment (2), in order to improve the properties of the obtained reclaimed vulcanized fluororubber (C), the molded product obtained by the above vulcanization 17 is subjected to secondary vulcanization by further heating. May be used.

The reclaimed vulcanized fluororubber (C) obtained by the method for producing a reclaimed vulcanized fluororubber of the present invention may be composed of other compounding agents, if necessary, in addition to the crosslinking molecule and the vulcanizing additive. . The above other compounding agents are not blended with non-vulcanized fluororubber, composites, regenerated vulcanized fluororubber (Α) and Ζ or regenerated unvulcanized fluororubber (Β). Can be. The above-mentioned other compounding agents are not particularly limited. For example, various compounding agents generally used for rubber can be used. Examples of such compounds include fillers, processing aids, plasticizers, and softeners. Agents, anti-aging 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; magnesium carbonate Carbonates such as aluminum, 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 Metal sulfides such as sulfide, molybdenum disulfide, iron sulfide, and sulfur sulfide, as well as diatomaceous earth, asbestos, lithobon (zinc sulfide / barium sulfide), graphite, carbon black, carbon fluoride, calcium fluoride, Coke, wet silica, dry silica Quartz fine powder, zinc oxide, talc, mica powder, Wallace Tokyo DOO, carbon fibers, Arami de fibers, each species Uisuka, 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; stearic acid amide, oleic acid amide; Higher fatty acid esters such as ethyl oleate; higher aliphatic amines such as stearylamine and oleylamine; petroleum-based waxes such as carnauba wax and ceresin wax; ethylene glycolone, glycerin, diethylene glycol and the like. Polyglycorone; ヮ In addition to other aliphatic hydrocarbons such as serine, paraffin, etc., silicone oil, silicone polymer, low molecular weight polyethylene, phthalates, ester phosphates, rosin, dianolequinoleamine, halogen Jianore Kill Min, Jianorekinore sulfonated, halogenated dialkyl sulfone, surfactants, and the like. Examples of the plasticizer include phthalic acid derivatives and sebacic acid derivatives.Examples of the softening agent include lubricating oil, process oil, coal tar, castor oil, calcium stearate, and the like. Examples thereof include phenylenediamines, phosphates, quinolines, cresols, phenols, and dithiocarbamate metal salts. As the other compounding agents described above, a coloring agent, an ultraviolet absorber, a flame retardant, an oil resistance improver, a foaming agent, a scorch inhibitor, a tackifier, a lubricant, and the like can be arbitrarily compounded.

The reclaimed vulcanized fluororubber (C) obtained by the method for producing a reclaimed vulcanized fluororubber of the present invention has excellent heat resistance, oil resistance, solvent resistance, chemical resistance, weather resistance, and the like. It can be used in the same manner as vulcanized fluororubber obtained by vulcanization, and can withstand sufficient use even under severe conditions such as exposure to high temperatures and chemicals. Having.

Applications of the reclaimed vulcanized fluoro rubber (C) include, for example, parts for automobiles. Parts for automobiles include, for example, the engine itself; the engine's main motion system, valve train, lubrication / cooling system; fuel system, intake / exhaust system, drive system transmission system, etc .; chassis steering system, brake system, etc. Electrical components such as basic electrical components, electrical components for control systems, and electrical components.

Applications of the recycled vulcanized fluoro rubber (C) include sealing materials, bellows, diaphragms, hoses, tubes, electric wires, etc., and these are particularly heat-resistant, oil-resistant, fuel-oil-resistant, and LLC-resistant. And those requiring steam resistance are preferred. Examples of the sealing material include gaskets, non-contact type and contact type packings, and examples of the packings include self-sealing packing, piston ring, split ring type packing, mechanical seal, and oil seal. Can be Recycled vulcanized rubber (C) can be used for the following specific applications, for example.

Gaskets such as cylinder head gasket, cylinder head cover gasket, oil pan packing, general gasket, etc. in the automobile engine body; o-rings, packing, timing blanket cover gasket, etc .; Hose; anti-vibration rubber for engine mount, etc.

Shaft seals such as crankshaft seals and camshafts in the main motion system of automobile engines.

Valve stem oil seals for engine valves in automotive engine valve trains. In the lubrication and cooling systems for automobile engines, engine oil cooler hoses, oil return hoses, seal gaskets, etc. for engine oil coolers, tertiary hoses around radiators, and vacuum pump oil / rehousing for vacuum pumps.

Oil seals, diaphragms, valves, etc. for fuel pumps in automotive fuel systems; filler (neck) hoses, fuel supply hoses, fuel return hoses, fuel hoses such as vapor (evaporative) hoses; fuel tank in-tank hoses, fillers Seals, tank packings, ink tank fuel pump mounts, etc .; fuel tube tubes and connector O-rings, etc .; fuel injector injector rings, injector sino ring, injector ring, plenum regulator diaphragm, Check valves, etc .; carburetor needle valve petals, acceleration pump pistons, flange gaskets, control hoses, etc .; valve seats, diaphragms, etc. for combined air control equipment (CAC). In the intake and exhaust systems of automobiles, intake manifold packing for exhaust manifold, exhaust manifold packing, etc., EGR (recirculation during exhaust) diaphragm, control port one hose, emission control hose, BPT diaphragm, etc. Throttle body packing, throttle body packing, turbocharger turbo oil hose (supply), turbo oil hose (return), turbo air hose, intercooler hose, turbine shaft seal, etc. .

In automotive transmission systems, transmission bearing bearings, oil seals, O-rings, packing, torque converter hoses, etc., AT transmission oil hoses, ATF hoses, O-rings, packings, etc.

Power steering oil hoses, etc. in the steering system of automobiles.

In automotive brake systems, oil seals, O-rings, packing, brake oil hoses, master back air valves, vacuum valves, diaphragms, etc. Master, cylinder-to-cylinder biston cups (rubber cups), etc. Carrier seals, boots Types of basic electrical components for automobiles, such as electric wire (harness) insulators and sheaths Tubes for exterior parts.

Coating materials for control sensors of automobiles, along with various sensors.

O-rings, packings, coolers, hoses, etc. for car air conditioners in electrical equipment of automobiles.

Other than for automobiles, for example, oil-resistant, chemical-resistant, heat-resistant, steam-resistant and Z- or weather-resistant packing or other sealing materials, o-rings, hoses, diaphragms, valves, etc. in transportation such as ships and aircraft; Packings, such as seals, seals, diaphragms, banolebs, hoses, lorenoles, tubes; pharmaceutical coatings and linings; similar packings in food plant equipment and food equipment (including household goods), ο-rings, Hoses, seals, belts, diaphragms, valves, rolls, tubes; similar packing in nuclear plant equipment; o-rings, hoses, see-through materials, diaphragms, vanolebs, tubes; similar packing in general industrial parts; One ring, hose, sea Wood, diaphragms, are suitable valves, rolls, tubes, linings, Mandorenore, wire, Furekishibu Le joint, belt, rubber plate, a weather strip, in applications such Rorupu grade of P P C copier.

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

The composition for a reclaimed unvulcanized fluororubber of the present invention may be used in the method for producing a reclaimed vulcanized fluororubber of the present invention, if necessary, in addition to the reclaimed unvulcanized fluororubber (B) and the vulcanizing agent. In the same manner as described above for the recycled unvulcanized fluororubber (B), a vulcanizing additive other than the vulcanizing agent, a compounding agent, and Z or unvulcanized fluororubber. Is also good.

The composition for reclaimed unvulcanized fluororubber of the present invention has a processable viscosity. is necessary. The viscosity is the same as that described above for the regenerated vulcanized fluoro rubber (B) in the method for producing a regenerated vulcanized fluoro rubber of the present invention.

Since the composition for a reclaimed unvulcanized fluororubber of the present invention is the above-mentioned composition, it is possible to regenerate the vulcanized fluororubber by performing the above vulcanization treatment (2). It is. When performing the above-mentioned vulcanization treatment (2) to the composition for a reclaimed unvulcanized fluororubber of the present invention, usually the molding as described above for the method of producing a reclaimed vulcanized fluororubber of the present invention is carried out simultaneously. The composition for reclaimed unvulcanized fluororubber of the present invention can be represented in the following two ways.

The first composition for a regenerated unvulcanized fluororubber according to the present invention is used for obtaining a regenerated vulcanized fluororubber (C) by vulcanization. ) And a vulcanizing agent, wherein the unrecured unvulcanized fluororubber (B) is obtained by heat-treating the regenerated vulcanized fluororubber (A), and Vulcanized fluoro rubber (A) is characterized by being obtained by vulcanization (1).

The second composition for a regenerated unvulcanized fluororubber of the present invention is used for obtaining a regenerated vulcanized fluororubber (C) by vulcanization, and comprises a regenerated unvulcanized fluororubber (B). ) And a vulcanizing agent, and the reclaimed unvulcanized fluororubber (B) is composed of a crosslinkable fluoropolymer, and the crosslinkable fluoropolymer contains iodine. It has no bromo group and has an ionic group such as a carboxyl group in the side chain.

In the second composition for reclaimed unvulcanized fluororubber of the present invention, the crosslinkable fluorine-containing polymer is as described above in the method of producing reclaimed vulcanized fluororubber of the present invention. Therefore, the crosslinkable fluoropolymer may be one obtained by heat-treating a vulcanized fluororubber obtained by peroxide vulcanization. In this case, the peroxyside vulcanization results in It has no iodine and no bromine, and as a result of decomposing the crosslinked site by the above heat treatment, it has an ionic group such as a carboxyl group in the side chain.

A reclaimed vulcanized fluororubber characterized by being obtained from the composition for a reclaimed unvulcanized fluororubber is also one of the present invention. This recycled vulcanized rubber is As described above, the recycled vulcanized fluororubber (C) obtained by the method for producing a recycled vulcanized fluororubber of the present invention.

The method for producing a reclaimed vulcanized fluororubber of the present invention is characterized in that a vulcanization treatment is performed on the composition for a reclaimed unvulcanized fluororubber to obtain a reclaimed vulcanized fluororubber. It is. 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 reclaimed vulcanized fluororubber of the present invention, and the reclaimed vulcanized rubber is used in the method for producing a reclaimed vulcanized fluororubber of the present invention. This is the recycled vulcanized fluorine rubber (C). Therefore, the recycled vulcanized fluororubber (C) can also be regenerated by the second method for producing a reclaimed vulcanized fluororubber of the present invention. Embodiment of the Invention

Example 1

Fluororubber (Iodine-containing VdFZTFEZHF P copolymer, trade name: Daiel G-952, manufactured by Daikin Industries, Ltd.) MT carbon black (trade name: Thermax N—990, Cancarb) 20 parts by weight, Triallyl isocyanurate (TA IC, manufactured by Nippon Kasei Co., Ltd.) 4 parts by weight, Peroxide (trade name: Perhexa 2.5B, manufactured by Nippon Yushi Co., Ltd.) 1.5 parts by weight , Kneading using two rolls, press vulcanization at 160 ° C for 10 minutes, and oven vulcanization at 180 ° C for 4 hours. It was made.

The regenerated vulcanized fluororubber (A) was pulverized using two rolls and heated in an oven at 300 ° C. for 70 hours to produce a regenerated unvulcanized fluororubber (B). This recured unvulcanized fluororubber (B) is kneaded with a roll in the composition shown in Table 1, then polyol vulcanized, press vulcanized at 170 ° C for 20 minutes, and cured at 230 ° C for 24 minutes. Oven vulcanization was performed for an hour to produce a recured vulcanized fluoro rubber (C). The vulcanizability of the kneaded compound was measured using a curast meter (manufactured by JSR). Table 2 shows the measured results.

The recycled vulcanized fluoro rubber (C) is drawn according to JISK 6251. Tensile strength and elongation at break were measured, and hardness (shore A) was measured according to JISK 6253. In addition, a compression set test was performed. Table 3 shows the measurement results. Example 2

Instead of polyol vulcanization, polyamine vulcanization was carried out with the composition shown in Table 1, and press vulcanization was performed at 160 ° C for 20 minutes during the production of regenerated vulcanized fluororubber (C), followed by oven vulcanization at 200 ° C. A recycled vulcanized fluororubber (c) was prepared and measured in the same manner as in Example 1 except that C was performed for 24 hours. Tables 2 and 3 show the measurement results. Example 3

A recured vulcanized fluororubber (C) was prepared in the same manner as in Example 1 except that vulcanization was carried out in combination with ion vulcanization and polyol vulcanization in the composition shown in Table 1 instead of vulcanization with polyol. A measurement was made. Tables 2 and 3 show the measurement results. Comparative Example 1

Using 100 parts by weight of fluoro rubber (Vd FZTFE / HFP copolymer containing iodine, trade name: DAIEL G_952, manufactured by Daikin Industries, Ltd.) This was performed at 170 ° C for 20 minutes, and oven vulcanization was performed at 230 ° C for 24 hours to produce a fluororubber. The same measurement as in Example 1 was performed. The measurement results are shown in Tables 2 and 3. Comparative Example 2

Using 100 parts by weight of fluorine rubber (VdF / TFE / HFP copolymer containing iodine, trade name: DAIEL G-952, manufactured by Daikin Industries, Ltd.) Sulfurization was performed at 160 ° C for 20 minutes, and oven vulcanization was performed at 200 for 24 hours to produce a fluororubber. The same measurement as in Example 1 was performed. The measurement results are shown in Tables 2 and 3. table 1

(Unit: parts by weight) In Table 1, each trade name and abbreviation are shown below.

Bisphenolone A F: 2,2-bis (4-hydroxyphenol) perfluor

DBU-B: 8-Benzyl-1,8-diazabicyclo [5.4.0] — Ί—dedecenium hydroxide

Vulcanizing agent V—3: N, N'-dicinnamylidene 1,6-hexanediamine, Dacardic # 2000: Calcium hydroxide, manufactured by Omi Chemical Industry Co., Ltd.

Kiyomag 150: Highly active magnesium oxide, manufactured by Kyowa Chemical Industry Co., Ltd.

Kiyomag 30: Low activity magnesium oxide, manufactured by Kyowa Chemical Industry Co., Ltd.

Stearic acid: First-class reagent

ZnO: zinc oxide, manufactured by Sakai Chemical Industry Co., Ltd. Table 2

From Table 3, it can be seen that 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, the hardness (shore A) was found to be about the same. Industrial applicability

Since the method for producing a reclaimed vulcanized fluororubber of the present invention has the above-described configuration, the vulcanized fluororubber can be regenerated from the vulcanized fluororubber through recasting. The composition for unrecured unvulcanized fluororubber of the present invention enables such re-vulcanization, and the obtained reclaimed vulcanized fluororubber is the same as the fluororubber obtained by the first vulcanization. It has a wide range of uses.

Claims

The scope of the claims

1. After heating the regenerated vulcanized fluororubber (A) to obtain a regenerated unvulcanized fluororubber (B), the regenerated unvulcanized fluororubber (B) is subjected to vulcanization (2). A method for producing a reclaimed vulcanized fluororubber comprising obtaining a reclaimed vulcanized fluororubber (C) by applying

The method for producing a reclaimed vulcanized fluororubber, wherein the reclaimed vulcanized fluororubber (A) is obtained by a vulcanization treatment (1).

2. The method for producing a reclaimed vulcanized fluororubber according to claim 1, wherein the heat treatment is performed at 240 ° C to 400 ° C.

3. The method for producing a reclaimed vulcanized fluororubber according to claim 1 or 2, wherein the vulcanization treatment (1) uses a peroxide.

4. The reclaimed vulcanized fluororubber (A) is obtained by subjecting a copolymer obtained from a monomer component containing vinylidene fluoride to a vulcanization treatment (1). 4. The method for producing a reclaimed vulcanized fluororubber according to item 1, 2, or 3.

5. The reclaimed vulcanized fluororubber (A) is composed of a copolymer having a portion represented by one CFR ¹ — CH ₂ _ (R ¹ represents a bridge portion) in the main chain. 5. The method for producing a reclaimed vulcanized fluoro rubber according to claim 1, 2, 3, or 4.

6. The recycled unvulcanized fluororubber (B) is made of a crosslinkable fluoropolymer,

The vulcanization treatment (2) comprises reacting a crosslinkable site of the crosslinkable fluoropolymer,

The crosslinkable site is (i) a site in the main chain represented by one CFR ² —CH ₂ — (R ² represents a fluorine atom or a residue of a crosslinkable site), or (ii) an ionic group. is there 6. The method for producing a reclaimed vulcanized fluoro rubber according to claim 1, 2, 3, 4 or 5.

7. The vulcanization treatment (2) is a vulcanization method using a polyamine, a vulcanization method using a polyol, and a vulcanization method using Z or an ionic group generated by heat treatment. Method _{c for} producing reclaimed vulcanized fluoro rubber according to item 1, 2, 3, 4, 5 or 6

8. A composition for a regenerated uncaro-sulfurized fluororubber used for obtaining a recured vulcanized fluororubber (C) by vulcanization,

It is composed of a recycled unvulcanized fluoro rubber (B) and a vulcanizing agent,

The regenerated unvulcanized fluoro rubber (B) is obtained by subjecting the regenerated vulcanized fluoro rubber (A) to a heat treatment,

The composition for a non-vulcanized unrecured fluororubber, wherein the regenerated vulcanized fluororubber (A) is obtained by a vulcanization treatment (1).

9. The composition for a non-vulcanized recycled rubber according to claim 8, wherein the vulcanizing agent is a polyol, a polyamine and / or a metal oxide.