CH626382A5 - Process for the vulcanisation of fluorinated elastomers - Google Patents

Description

The invention relates to a process for the vulcanization of fluoroelastomers by means of suitable crosslinkable compositions with improved processability, containing additives of certain.

45

organophosphorus or organosulfur oxides that harden faster than previously known masses without losing their valuable physical properties.

In general, linear polymers are thermoplastic and flow under the influence of heat and pressure. Such polymers can be softened any number of times and are usually soluble in selected solvents. However, crosslinked or vulcanized polymers are generally hot-curing, that is insoluble in most solvents and cannot be softened without decomposition, since they are permanently hardened. A linear polymer can still contain a small amount of crosslinking without completely losing its thermoplastic properties. It is generally favorable to convert thermoplastic polymers into cross-linked elastomers in order to reduce their solubility and thermoplastic flow properties and to obtain a harder and tougher product. The crosslinking of elastomers is generally referred to as vulcanization.

The most difficult vulcanizable thermoplastic polymers include those made by polymerizing halogenated monoolefins, such as the copolymers of chlorotrifluoroethylene and vinylidene fluoride, the copolymers of perfluoropropene or penta-

65

fluoropropene and vinylidene fluoride and the terpolymers of perfluoropropene, vinylidene fluoride and tetrafluoroethylene. Many of these fluorinated thermoplastic polymers have unique and valuable properties. The polymers are cross-linked in order to maintain these properties and at the same time reduce their thermoplastic flowability and solubility.

In order to make a molded cured product from a fluoroelastomer such as the one given above, a difficult process must be used in which each step affects both the properties and the cost of the final product. First of all, a uniform mixture of the desired composition from the rubber-like starting material and the fillers, hardening agents, processing aids, etc. must be produced. Mixing can be carried out, for example, with a "Banbury" internal mixer or on a roller mill with two rollers, but due to the toughness of the rubber-like starting material and the intensive mixing action, considerable internal heat is developed, which must be controlled to prevent premature curing , which would make suitable molding impossible. The mixing can best be carried out in such a way that the temperature of the mass does not rise above 120 ° C. and is preferably kept between 95 and 120 ° C. by appropriate cooling. The starting rubber-like (vulcanizable) mixture to be obtained can be set aside for any time, which can range from a few hours to months, until the final molding is carried out. This molding can be carried out by extrusion, by molding using closed molds, or by any other molding process as is common in the elastomer industry. In most cases, the product is molded by compression molding. In this operation, the rubbery mixture can be heated to the desired temperature, generally in the range of 150 to 205 ° C, and mechanically pressed into the mold, which can be preheated to the appropriate mold temperature. Alternatively, a weighed amount of the rubbery mixture can be placed in the mold and the mold closed and heated. With each process, the mixture must flow evenly in the entire form and fill the entire interior and flow together evenly so that no boundary layer between two or more flow areas is created. Hardening usually begins at the molding temperature, which must proceed to an extent sufficient for the molded body to retain its shape and for no tears to form when it is removed from the mold. The higher the molding temperature, the faster such a state of «pressure hardening» can be achieved. However, there must be sufficient time for the mold to fill evenly and therefore there is a maximum temperature in practice. Ideally, the viscosity should not increase significantly during the initial flow through which the mold fills, but should subsequently increase very quickly in order to make the molded body sufficiently stable so that it can be removed from the mold.

After removal from the mold, the molded body is usually post-cured or oven-cured. If curing is not sufficiently advanced during molding, the gases released during the final curing can lead to blistering and destruction of the molded body.

The applicability of cured fluoroelastomers depends on their resistance to solvents, their good properties when exposed to pressure (permanent deformation) and the stability of their properties at elevated temperatures. These properties, combined with those in general

3,626,382

good elastomeric properties of fluoroelastomers have led to the development of comparatively less mass for the vulcanization of elastomeric copolymers - for economical use - which requires a shorter time for pressure curing without sen, in which the molar main part - usually that the psychological properties of the cured product Vinylidene fluoride - can be adversely affected with smaller molar amounts of perfluoro.

propylene, tetrafluoroethylene, trifluorochloroethylene and / or 5 This object is achieved by a process for vulcanized monohydroperfluoropropylene being used together. In the allinizing of elastomeric copolymer of vinylidene fluoride and the like, some filler is required, as is customarily used in at least one terminally unsaturated fluorinated mono-mode, although in general a medium-strength olefin as a comonomer, which is used as a substituent other than fluorine-increasing soot . least chlorine or a fluoroalkoxy group with 1 to 4

Since the properties of the hardened product largely contain 10 carbon atoms and have at least 1 fluorine atom on each of the double-bonded carbon atoms determined by the special hardening system used, most of which are improvements in the properties of the at least 10% of the carbon atoms in the chain of the copolymer as a final product has been achieved by an improvement in the hardness -CH2 groups present, by heating under pressure of a system. The hardening system determines the conditions of the mixture, the copolymer of this type and, moreover, per 100 of the mixing, molding and hardening, which have a major influence 15 parts by weight of this copolymer 0.1 to 5 parts by weight quater on the cost of the end product and on the physical ammonium - or phosphonium compound, 0.2 to 5 ge-calic and chemical properties. parts by weight of aromatic hydroxy or amino compound and

The polyamine curing system, which first contains the 3 to 40 parts by weight of at least one acid acceptor,

satisfactory commercial products is still characterized in that the mixture an additional 0.2 to 5 is always important. Long experience with polyamine system- 20 parts by weight of a compound of formula (RO) 3PO,

men has resulted in safe handling and reliable supply (RO) 2 (NH) PO, (R) 3PO, (R) 2SO or (R) 2S02, where R work, the main difficulty being an optionally substituted one , if necessary, that the products easily remain an alkyl, cycloalkyl or aryl group containing ro atoms after prolonged use and suffer deformation (compression set). which is free of strongly acidic and strongly basic substituents

25 and 1 to 20 carbon atoms, or two R instead - A hardening system based on quaternary together means an alkylene group, and that 30 s to 15 ammonium compounds, which is many of the inexpensive handles under a pressure of 7 up to 210 kg / cm2 to 95 to exercise properties of the polyamine system, but heated to a 230 ° C and then leads up to 50 h at 150 to 315 ° C after the end product, which cures a much better resistance.

compared to permanent deformation, is shown in US Pat. No. 30 It has been shown that it is described when using Diorgano-3,655,727. This hardening system allows silicon sulfoxides or sulfones or triorganophosphorus oxides to be processed more frequently on the roller mill at 90 to 120 ° C. and it is possible to use less Ca (OH) 2 as an acid acceptor - mold temperatures in the range from 160 to 170 ° C. which is the one where the hardening speed improves and the er flow properties are good and the hardening cycle is short. desired physical properties - such as the resistance - the hardening time is even so short at these temperatures, 35 ^ time against permanent deformation - can be improved,

that the mixture must be handled carefully in order to be compared to known products. The masses can prevent partial hardening during processing. In be self-lubricating, whereby an extrusion under US Pat. No. 3,752,787 makes it possible to use low pressure triarylphosphorus and as a result the surfaces are given an excellent appearance as accelerators together with quaternary ammo- and the moldings are easily described as nium derivatives. 40 can be removed from <those shapes. In the case of the

To a certain extent, the mass-produced compositions described above overcome the use of means of difficulty by using a quater-easier removal of the molded body from the mold in the när phosphonium salt curing system, in which a connection is no longer required.

is present in which the phosphorus atom is covalently bonded to the 4

Carbon atoms and ionically linked to an anion 45 polymers are preferably linear saturated fluorinated polymers, (U.S. Patent 3,712,877). The covalently bonded radicals can be the further, non-reacting substituents such as fluorine or - 'straight-chain, branched or cyclic organic radicals. Can contain chlorine atoms and the at least half a ha-They can be saturated, unsaturated or aromatic. Im generalized. The expression «half halogenated»

I believe there are 4 monovalent organic radicals, although it should be understood that at least half of the phosphorus atom on carbon can also be part of a heterocyclic ring and 50 bonded hydrogen atoms of the analog non-halogenated one. Quaternary phosphonium compounds are replaced by halogen atoms in the general polymer. The preferred polymers that can be vulcanized together with a nucleophilic organic compound are generally used at least in the case of manure in which one or more hydroxyls, primarily fluorinated, are halved. However, it is important that the polymer chain contains amino or secondary amino groups via the oxygen -CH2 units. Homopolymers made from tetrafluoroethylene atom or the nitrogen atoms attached to an aromatic nucleus (j other perfluorinated comonomers require very high bonds. Usual acid acceptors, modifiers, temperatures to achieve crosslinking. Such and fillers, especially soot types, can be used here homopolymers not under the present invention.

will. Such systems are safer than the quaternary ones

Ammonium systems, lead to good flow properties in linear fluorinated elastomers generally contain unordered shaping and favorable curing times in a tempera- 60, saturated, fluorinated carbon chains that have a temperature range between approximately 150 and 230 ° C and especially with a considerable number of - Contain CH2 groups, usually about 175 to 190 ° C. The characteristic curves of at least 10% of the chain carbon atoms. The disorder of viscosity versus time for preparations of this type up to in the carbon chains is usually achieved by a certain point and then a very rapid increase, copolymerization of at least two monoolefinic compounds, and thereby permitting reliable mixing on the roller connections Kind described later. If one of the mo chair or in the internal mixer, a longer storage and a noolefinic compounds an unsaturated chain of 3 economical curing under pressure. or contains more carbon atoms are formed in the

It is an object of the present invention to provide a method of polymer alkyl side chains, e.g. Methyl, ethyl or similar

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che groups, and these alkyl groups are particularly favorable in this context. Mixtures of white perhalogenated, especially perfluorinated. Places lacking - elastomers can also be suitable, for example a balance, which is required for the elastomer properties of a mixture of 70-95 parts of an elastomeric perfluoropropene, are generated by these side groups. The vinylidene fluoride copolymer and 30-5 parts of an elastomer

like side groups lead to a bending of the linear 5 ren trifluorochloroethylene-vinylidene fluoride copolymers.

Carbon chain and thus to a further degree of freedom in the additives mentioned in the process according to the invention.

Space through which the carbon chain to which they are attached turns organic oxides are compounds containing 1

becomes asymmetrical. However, an imbalance can also be a phosphorus atom with an oxygen atom bound exclusively to the phosphorus atom through the presence of other asymmetrical units, or a sulfur atom with 1 or 2

in the linear carbon chain, such as 10 oxygen atoms bound exclusively to the sulfur atom

through CFCl groups. Regardless of the units that add and two or three organic residues that lead directly to such imbalances, be it two physical CS or CP bonds or on phosphorus via COP or different substituents or a side group on C-NH- P bonds are bound. The connections used

a chain carbon atom, if at least 10% of the chain fertilizers are diorganosulfoxide (R2SO), diorganosulfonic carbon atoms are unbalanced. 15 (R2S02), triorganophosphine oxides (R3PO), triorganophospha-

The linear, saturated, fluorinated carbon chain of the egg (RO) 3PO), triorgano-amido-phosphate (RO) 2RNHPO),

stomers can also contain chlorine substituents, where on a wherein R each has an organic radical defined below, a single carbon atom of the chain means no more than 1 chlorine atom. Such substances are e.g. described in "Basic should be bound to result in instability or the Principles of Organic Chemistry" by Roberts and Caserio,

influence the chemical nature of the elastomer. The existence of 20 W.A. Benjamin Company, New York, N.Y., 1965, particularly the presence of more than 1 chlorine substituent on a coal side 756-760; "Organic Syntheses", vol. 1, pages 718-725,

The chain's fabric atom results in a rigid point in the chain, Volume II, pages 1709-1715, Reinhold Publishing Co., New, which reduces the flexibility of the chain and the elasto- York, N.Y. 1957, Kosolapoff, «Organophosphorus Com-

properties deteriorate accordingly. pounds », Chapter 9, John Wiley and Sons, New York, 1950;

Regarding the saturated polymers that Kosolapoff and Meier, “Organic Phosphorus Compounds,”

the fluorinated elastomeric Co-Volume 3, Chapter 6, Wiley Interscience, 1972.

polymers of vinylidene fluoride and chlorotrifluoroethylene, per- The organic radicals (R) may be the same or different - fluoropropene, tetrafluoroethylene, 1-hydroperfluoropropene (i.e. lent and each radical contains 1 to 20 carbon atoms, CFH = CFCF3) and trifluoroethylene. These mono-olefins, although 1 to about 8 carbon atoms are preferred, can be combined with one another in groups of two or more copolymerized, generally no more than 30 carbon atoms. The elastomers are copolymers of vinylidene, sulfur or phosphorus. Two radicals R can mean fluoride with at least one terminally unsaturated fluorine group, an alkylene group, a heterocycli-monoolefin containing at least 1 fluorine atom being formed on each double ring. The carbon chain of the radicals R can be pelt-bonded carbon atom, the fluoromooloolefin being linear, branched or cyclic and can be aliphatic or at most aromatic by chlorine or a fluoroalkoxy group having 1 35 and non-carbon atoms such as oxygen atoms to 4 carbon atoms are substituted. In addition to the carbon atoms, pearls are particularly contained. The chain can be fluoropropene, tetrafluoroethylene, chlorotrifluoroethylene and / or substituted or unsubstituted. The substituents - as far as called 1-hydroperfluoropropene. Those which are present are particularly preferred - but should usually be, for example, newly fluorinated elastomers which can be obtained by means of cotra, i.e. they must be neither strongly acidic nor strongly basic polymerisation of perfluoropropene and vinylidene fluoride (US-40, although active weakly acidic hydrogen atoms, such as al. PS 3,051,677 and 3,318,854), and such terpolymers, the erphatic hydroxyl groups, in small Quantities e.g. can be maintained at 0.5 by copolymerization of perfluoro% or less based on the compound, propene, vinylidene fluoride and tetrafluoroethylene (U.S. Patent No. Neutral substituents include Halogenato-2 968 649, among others). The perfluoropropene elastomeric copolymers containing ether, 0 = SR—, 02SR—, OP (OR) 2—, ester, oxohydr and vinylidene fluoride, between about 15 and 45 oxyl, nitro, CN, Alkyl and aryl groups.

- Dangerous 50 mol% perfluoropropene, are generally in the - Typical diorgano sulfur oxides include

(ch3) 2so (c4h9) 2so ch3 (c8f17) s0 h2c ch2

so,

h2c ch2

(ClC6H4) 2SO

(c2h5oc2h4) 2so

(ch3-ch2-ch2) 2so

C2H5S02C2H40C2H5

c2H5SOC4H8soc2Hs c2h5soc4h8soc2h5 (ch3-ch2-ch2) 2so2 c6h5soch2c6h5 c6h5so2ch2c6h5

(ch3) 2so2

(c4H9) 2so2

ch3 (c8fi7) 2so2

H2C CH,

so,

h2c ch-,

(c1c6h4) 2s02

(c2h, oc2h4) 2so2

c2h5so2c4h8so2c2h,

c2h5so2ch2ch2ocöch3

CHClCHiCH2CH2S02CfiH5

ch3c6h4so2ch2ch2ch2ch2cn c4h9so2c4hhno2 ch3coch2ch2so2c4h9 c3f7ch2so2ch2c3f7

Typical triorganophosphorus oxides include

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(CH3) 3PO

(C18H37) (C2H5) 2PO

(CH2 = CH-CH2) (C4H9) 2PO

(Br CH2CH2CH2) (C4H9) 2PO

(C6H5) 3PO

(C ^ XQH ^ PO

(Cyclo-C6H ") 2 (C4H9) PO

(C2H50) 2 (CH3C02CH2CH20) P0

(CIC6H4) 3PO

(c4h90) 2 (ncœ2ch2ch2ch2ch20) p0 (c2h5o) 3po

(c4h90) 2 (02nch2ch2ch2ch20) p0

(c18h370) (c2h50) 2p0

(c4h90) 2 (ch3c0ch2ch20) p0

(c1ch2ch20) 3p0

(c4h90) 2 (ch2c1ch2ch-, ch20) p0

(c6h5ch20) 3p0

(c2f50cf2cf20cf2ch20) 3p0

(ch3c6h40) 3p0

(ch2 = ch-ch20) 3p0

(c4h90) 2c4h9nhp0

(c6h5) 2p (ch2c6h5)

o o o o

Il II II

(C2HsO) 2P OC4H8OP (OC2H5) OC4H8OP (OC2H5) 2

ch3 ch3 o I I II

ch3ch2ch2o (c hch2o) 4c h-ch2OP (OC2Hs) 2

The quaternary phosphonium compounds that are used for the manufacture, if any, are not strong

The position of the vulcanizable fluoroelastomer masses should be suitable for 25 acidic residues (e.g. residues that are derived from are compounds that usually add at least 1 acid with a dissociation constant in water

Contain phosphorus atom covalently over a carbon 25 ° C of at least 10 ~ 5, e.g. Carbon, sulfone or phos

Single phosphorus bond to 4 organic residues and additional phosphoric acids, although active weakly acidic hydrogen atoms,

is bound to an anion via an ionic bond. Such as in a hydroxyl group, in small amounts, e.g. 0.5% substances, their properties and various processes 30% by weight, based on the compound or below, available

for their production are described, for example, in “Organodes can be.

phosphorus Compounds »from G.M. Kosolapoff, (John Wiley Typical quaternary phosphonium compounds include

and Sons, New York 1950) especially Chapter 5.

The 4 organic radicals attached to each phosphorus atom can be the same or different and each radical (GH3) 2 (C2HS) 2P + CI-can contain from 1 to 20 or more carbon atoms, whether- (C2H5) 3 (C18H37) P + S04H_

2 to 8 carbon atoms are preferred and the total (cyclo-C6Hn) 2 (C6H13) 2P + N03_

number of carbon atoms should not be more than 30. The (C4H9) 3 (CH2 = CH-CH2) P + C1 ~

Carbon chain of the organic radical can be linear, branched 4q (C6H5) 3 (C6H5CH2) P + CH3C02 ~

or be cyclic and saturated, unsaturated or aromatic and (C6H5) 3 (CH30C2H5) P + C1_

can contain non-carbon atoms such as oxygen, nitrogen or (C8H17) 3 [(CH3) 2NCH2CH2CH2] P + C1_

Contain sulfur atoms in addition to the carbon atoms. The (C8H17) 3 (HOC2H5) P + CI_

Chain can be substituted or unsubstituted, the sub- Cl- + P (C2H5) 3CH2CH2CH2CH2 (C2H5) 3P + C1_

(i.e. tetrabutyl phosphonium captat).

Quaternary ammonium compounds which are suitable for the preparation of the curable fluoroelastomer compositions are compounds which generally contain at least 1 nitrogen atom which is covalently bonded to 4 organic radicals via a single carbon-nitrogen bond and additionally via an ionic bond to an anion. Such substances are e.g. in U.S. Patent 3,655,727, column 4, line 65 to column 5, line 2, and U.S. Patent 3,752,787, column 6, line 1 to 22

r r

CH

Ah

60 described. The 4 organic radicals attached to each nitrogen atom may be the same or different, and each radical may contain 1 to 20 or more carbon atoms, although 2 to 8 carbon atoms are preferred and the total number of carbon atoms should not exceed 30 65. The carbon chain of the organic radical can be linear, branched or cyclic and saturated or unsaturated. Compounds in which the nitrogen atom is bound to one or more aromatic rings have a relative

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low reactivity for curing and are generally less preferred. The rest can contain oxygen, nitrogen and / or sulfur atoms in addition to the carbon atoms in the chain. The chain can be substituted or unsubstituted, the substituents, if any, should preferably not be strongly acidic residues (ie, residues derived from an acid with a dissociation constant in water at 25 ° C of at least 10 ~ 5 or salts thereof, for example carboxylic, sulfonic or phosphoric acids or their salts), although active weakly acidic hydrogen atoms, such as an aliphatic hydroxyl group, can be present in small amounts, for example 0.5% by weight or less based on the compound.

Typical quaternary ammonium compounds include

(ch3) 3n + oh- (c4h9) 3n + c1-

ho- (c4h9) 3n + ch2ch2n + (c4h9) oh-

N + (CH3) 2CH3C02

(C4H9) 3 (CH2 = CH-CH2) N + - OPO (OC2H5) 2 CF3CF2OCF2CF2OCF2CH2N + (C4H9) 3BF6-

25th

Quaternary phosphonium and ammonium compounds (H0) n (0H) n with a too high molecular weight generally diffuse less easily through the fluorocarbon polymer during the curing and thus lead to a certain unevenness in the curing and less favorable physical properties in the vulcanizate obtained . A generally satisfactory cure can be most conveniently achieved with a compound having a molecular weight of 35 not more than about 1000 and in most cases a molecular weight of not more than about 500 is preferred. in which A is a divalent aliphatic, cycloaliphatic or the type of anion is usually not critical and is an aromatic group having 1 to 13 carbon atoms or largely determined by the type of reactants, thio, oxy, carbonyl, sulfinyl or sulfonyl group which were used in the preparation of the phosphonium compounds, which were optionally used with at least 1 chlorine or fluorine atom. The anion is generally monovalent but it is substituted and x is 0 or 1 and n is 1 or 2 and each aromatic may also be divalent or polyvalent. Typical anions are see rest of the polyhydroxy compound optionally substituted-the chloride, bromide, hydroxyl, methoxy, acetate, mercap ated by at least 1 chlorine, fluorine and / or bromine atom tat-, sulfate, bisulfate and similar. Neutral salts are in the can. From the bisphenol formula given above, rule against acidic or basic phosphonium or “that the —OH groups can be in any position (except for ammonium compounds preferably because of their better 1-position) in each ring. Mixtures of stability and ease of handling, although it should be noted that two or more such compounds can also be used during the mixing in their basic form. One of the most suitable compounds can be converted into the form since the vulcanizable materials generally contain the bisphenol hexase known as bisphenol AF in large quantities of a relatively strong base 50 fluoroisopropylidene bis (4-hydroxybenzene). The compounds can be like magnesium oxide or calcium hydroxide. 4,4'-dihydroxydiphenyl sulfone (bisphenol S) and isopropyl

It is generally favorable, in addition to the quaternary phosphorus bis (4-hydroxybenzene) or bisphenol A, phonium or ammonium compounds, further curing agents, can also be regarded as very suitable bisphenols, as can tel. Such further hardening agents are hydroquinone. Other suitable connections are e.g. known and described in the literature, e.g. in U.S. Patent 55 catechol, resorcinol, 2-methyl-resorcinol, 5-methyl-resorcinol, 3,243,411 and 3,502,628. A particularly preferred group, 2-methylhydroquinone, 2,5-dimethylhydroquinone and 2 -t-bu-which is described in US Pat. No. 3,655,727 comprises the aromatic hydroquinone and also compounds such as 1,5-dihydroxynaphthalic hydroxy or amino compounds, ie nucleophilic thalin and 9,10-dihydroxyanthracene. Other compounds Compounds in which one or more hydroxyls are primary:

re amino or secondary amino residues via oxygen or 60

Nitrogen atom of the rest are bound to an aromatic ring such as a 1,4,9,10-tetrahydroxyanthracene ring, a phenyl, naphthyl or similar ring. 2,2 ', 4,4'-tetrahydroxybenzophenone. Other curing agents which contain two aromatic hydroxyl groups 2,4-dihydroxybenzophenone are generally particularly preferred. Such 2,4-dihydroxybenzoic acid further curing agents are described e.g. in U.S. Patent 65 4,4'-dihydroxytetraphenylmethane 3,752,787, column 3, line 33 to column 4, line 35 as di-, tri-2,6-dihydroxyanthraquinone and tetrahydroxybenzenes, naphthalenes and compounds of 3,6-dihydroxyxanthone Formula pyromellite bis (p-hydroxyphenylimide)

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2,4-dihydroxyacetophenone 4,4 'dihydroxybenzophenone 4,4'dihydroxydiphenyI-sulfoxide 2,4-dibenzoyl-resorcinol 2,4,5-trihydroxbutyrophenone 2,4-dihydroxbenzaldehyde

When moving from another curing agent to a given mass to another, one skilled in the art can determine the curing time and temperature that will result in a suitable curing rate for a particular application.

In the bisphenol of the formula given above, if it is an alkylene group, for example a methylene, ethylene, chloroethylene, fluoroethylene, difluoroethylene, 1,3-propylene, 1,2-propylene, tetramethylene, Chlorotetramethylene, fluorotetramethylene, trifluorotetramethylene, 2-methyl

1,3-propylene, 2-methyl-l, 2-propylene, pentamethylene, pentachloropentamethylene, pentafluoropentamethylene or hexamethylene group. If A is an alkylidene group, it can be, for example, an ethylidene, dichloroethylidene, di-fluoroethylidene, propylidene, isopropylidene, trifluoroisopropylidene, hexafluoroisopropylidene, butylidene, heptachlorobutylidene, heptafluorobutylidene, hexylidene, pentylidene, pentylidene, pentylidene - or 1,1-cyclohexylene group. If A is a cycloalkylene group, it can be a 1,4-cyclohexylene, 2-chloro-l, 4-cyclohexylene, 2-fluoro-l, 4-cyclohexylene, 1,3-cyclohexylene, cyclopentylene, chlorocyclopentylene , Fluorocyclopentylene or cycloheptylene group. Furthermore, A can be an arylene group such as an m-phenylene, p-phenylene, 2-chloro-l, 4-phenylene, 2-fluoro

1,4-phenylene, o-phenylene, methylphenylene, dimethylphenylene, trimethylphenylene, tetramethylphenylene, 1,4-naphthalene, 3-Huor-l, 4-naphthalene, 5-chloro-l, 4-naphthalene, 1,5-naphthalene or 2,6-naphthalene group.

Another component contained in the vulcanizable composition is an acid acceptor, preferably an inorganic acid acceptor. Suitable acid acceptors are bases such as magnesium oxide, lead oxide (lead smoothness, PbO), dibasic lead phosphite and zinc oxide, with magnesium oxide being preferred. The acid acceptors mentioned are preferably used in amounts of 3 to 25 parts per 100 parts of polymer. In addition, acid acceptors other than hardening accelerators are often favorable. These other acid acceptors are generally basic compounds and include inorganic oxides and hydroxides such as calcium hydroxide, barium carbonate, strontium hydroxide and the like. A total of 3-40 parts of acid acceptor per 100 parts of polymer are used.

Dimethyl sulfoxide is usually a typical diorgano sulfur oxide. However, diethyl sulfone, methyl benzyl sulfone, phenyl ether sulfoxide, methyl octyl sulfone and other such sulfoxides and sulfones as are commonly available can also be used. It is also possible to use triphenylphosphine oxide as a typical triorganophosphine oxide or other phosphine oxides such as tributylphosphine oxide, phenyldi-ethylphosphine oxide or diethyl octadecylphosphine oxide. Tri-butyl phosphate can also be a typical triorganophosphate, as can triethyl phosphate, methyl dibenzyl phosphate, phenyl diethyl phosphate and methyl dioctyl phosphate. It is easy for a person skilled in the art to carry out numerous variations within the scope of the invention. Exemplary phosphorus oxides include polyoxa chains, i.e. Polyoxyalkylene. Lower volatility can be easily achieved using polyphosphine oxides and polyphosphate esters.

The respective amounts of the individual components of a typical hardening system are given below in parts by weight. The amounts are given in parts per 100 parts of polymer (referred to as “parts”). Ranges generally apply to the respective amounts and the selection of the exact amount as a function of the curing time and temperature is obvious to the person skilled in the art.

Quantity ranges 5 component parts (range)

quaternary compound 0.1-5

Organosulfur or phosphorus oxide 0.2-5

Acid acceptors together 3-40

aromatic hydroxy or amino compound 0.2-5 io dung

Although suitable elastomers can be obtained using the quantitative ranges specified above, those with particularly favorable values with regard to the deformation remain if the relative amounts of the components are varied accordingly in the specified ranges.

Magnesium oxide is generally preferred as the acid acceptor. At least 3 parts are required to achieve adequate curing and curing speed. While a satisfactorily curable mass can be achieved using only 3 parts of calcium hydroxide, for example, it is generally preferred to use at least 1 part of acid acceptor such as magnesium oxide together with an an-25 the acid acceptor to provide better resistance to aging in the To achieve warmth. The maximum amount of acid acceptor indicated above is generally not critical and up to 40 parts can be used to obtain a suitable but hard mass 30. Generally, however, no more than about 25 parts are required for adequate curing. Optionally, zinc oxide, lead smoothness or dibasic lead phosphite can be used in approximately the same amounts and sometimes calcium oxide is used.

35 In addition to the former acid acceptors, another acid acceptor, if desired as an accelerator, is usually present in an amount of about 0.5 to 15 parts. Calcium hydroxide is generally preferred. Barium carbonate is somewhat weaker and is generally used in slightly larger amounts. In general, at least 3 parts of acid acceptors are used in total in order to achieve satisfactory curing. If 8 parts or more are used, the shrinkage can be reduced during processing on the roller mill and further processing.

Fillers can often be added to the above polymers to improve molding properties and other properties. When so used, a filler may be added to the mass to be vulcanized in amounts up to about 100 parts, preferably from about 15 to about 50 parts. Examples of suitable fillers can be reinforcing carbon blacks or non-black pigments with relatively low reinforcement properties, such as clay, barytes, silicon dioxide, silicates, etc. Plasticizers and processing aids, preferably esters and ketones, can optionally also be added.

The desired amount of the components of the crosslinking system is usually added to the unvulcanized fluorocarbon polymer (that is to say the rubber composition) and intimately mixed therewith using conventional rubber mixing devices, such as internal mixers, roller mills or other conventional mixing devices. It has been shown that an internal mixer is generally particularly suitable for large batches, since it requires less time than processing on the roller mill. The diorganosulfur oxides or triorganophosphorus oxides generally give adequate stability under the mixing conditions, even with systems

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8th

which can be cured very quickly under pressure, e.g. in 1 min at 90 ° C.

The hardening process usually comprises pressing the mixture in the mold or injecting it into the mold and then, after removal from the mold, that is to say removal from the mold, the hardening of the removed mold in the oven. In the process according to the invention, the pressing of the mixture (pressure hardening) is carried out at a temperature between 95 and 230 ° C., preferably between 150 and 205 ° C., for 30 s to 15 h, usually 1 min to 30 min. A pressure of 7 to 10 210 kg / cm2, preferably 35 to 70 kg / cm2, is applied to the mixture in the mold. The molds can be disassembled, coated with release agents - such as silicone oil - and preheated. The molded vulcanizate is then post-cured (oven cured) at a temperature of 150-315 ° C, usually 15 at about 205 ° C, for 2 hours or less up to 50 hours, depending on the thickness of the cross-section of the sample. The temperature during post-curing is usually gradually increased from the lower limit to the desired maximum temperature. The usually used maximum temperature is approximately 260 ° C and can be kept at this value for 24 hours or more.

The hardening properties are determined according to the American 25 Society of Testing Materials Test ASTM D 2084-7IT, using an oscillator frequency of 1.66 Hz and an arc of 30. The minimum torque and the “time up to 4.45 Newton (N) increase” are measures for the initial hardening speed, a measure for the resistance of the compound against scorching. The torque after 15 min and the time up to 223 N increase indicate the hardening rates and the ability of the material to harden adequately before demolding. Moldings with a size of 75 X 150 X 1.8 mm are produced and pressed at 35 70 kg / cm2 for 20 min at 160 ° C. The physical properties were measured on samples that would have been punched out of these films by the method specified under ASTM D 412-62T Form C.

The permanent set was carried out according to ASTM D 395-61B on rings with a diameter of 25 mm and a thickness of 3.4 mm, which were compressed to 2.7 mm under the specified conditions.

Various approaches were carried out for comparison (especially approaches 1-9 and 17-24 and 28) and to explain the process according to the invention and the masses in more detail (approaches 10-16, 25-27 and 29-37). The masses used and the respective curing properties and the properties of the cured polymer are given in Tables 1 to 8. In each of these batches, 100 parts of the copolymer of vinylidene fluoride and perfluoropropene in a molar ratio of 78:22 were used together with 30 parts of carbon black and the stated amounts of other substances. Tables 1 and 3 give the composition of the compositions for batches 1 to 8 and 9-18 and the properties of the compositions are given in Tables 2 and 4. The approaches 17-27 and 28-37 are described in Tables 5 to 7 and the properties in Tables 6 and 8.

The examples in which hexamethylenediamine carbamate is used (batches 22 and 23) show curing with polyamine with and without triorganophosphorus oxide, in this case tributyl phosphate. These examples show in particular that the use of a trialkyl or triaryl phosphate as plasticizer, as described by Dixon et al. In "Industriai and Engineering Chemistry", Oct. 1957, page 169, did not result in those obtained in the process according to the invention Results. It should be noted that phosphorus oxide does not significantly increase the cure rate and the cured product obtained has poor pressure resistance.

The comparative products of batches 9 and 28 require 3 minutes of hardening under pressure in conventional devices, while batches 10-14 and 29 (according to the invention) only require 1 minute. Batch 16 also takes 3 minutes, but reducing the amount of phosphonium chloride used leads to improved properties. Mixing was carried out on the roller mill and curing was carried out as described above.

Table 1

approach

1

2nd

3rd

4th

5

6

7

8th

Copolymer

100

100

100

100

100

100

100

100

Soot

30th

30th

30th

30th

30th

30th

30th

30th

MgO

3rd

3rd

3rd

3rd

3rd

3rd

3rd

3rd

Ca (OH) 2

6

6

6

6

6

6

6

6

2.2 bis (p-OH-phenyl) hexafluoropropane

2nd

2nd

-

-

-

2nd

2nd

1,4-dihydroxy-benzene

-

-

1

1

1

1

-

-

Tetrabutyl ammonium captate

0.4

0.4

0.4

0.4

-

-

-

-

Triphenyl-benzyl-phosphonium chloride

-

-

-

-

0.6

0.6

-

-

Tributyl allyl phosphonium chloride

-

-

- -

-

-

0.4

0.4

Tetramethylene sulfone

-

1

-

1

-

I.

-

1

Table 2

approach

1

2nd

3rd

4th

5

6

7

8th

Rheometer 175 ° C., 3 °, 1.66 Hz

Torque, minimum (N.m) 0

1.0

1.0

1.5

1.5

1.6

1.6

1.2

1.4:

Torque, iz min (rs.m;

12.1

12.0

12.8

12.5

10.4

10.5

11.9

11.8

Time to 4.45 Newton increase (min)

4.7

3.9

2.8

2.4

2.8

2.6

4.0

2.9

Time to 223 Newton increase (min)

6.9

5.7

4.2

3.6

4.6

4.1

5.7

4.2

Post-hardened (22 h at 260 ° C)

Tensile strength (kg / cm2)

136

133

102

115

112

116

136

131

Module (kg / cm2)

78

74

85

93

59

61

68

72

Elongation at break (%)

175

175

125

120

165

175

190

180

Hardness (Shore A2)

76

77

76

78

76

78

78

80

permanent deformation (72 h at 200 ° C) (%)

26

27th

23

34

25th

25th

21st

22

9

626 382

Table 3

approach

Copolymer

Soot

MgO

Ca (OH) 2

2,2-bis (p-OH-phenyI) hexafluoropropane

Triphenyl-benzyl-phosphonium chloride

Tetramethylene sulfone

Tetramethylene sulfoxide

Dimethyl sulfone

Dimethyl sulfoxide

Bis (p-chlorophenyl) sulfone

Table 4 Approach

Rheometer 177 ° C, 3 °, 1.66 Hz torque, minimum (N.m) torque, 12 min (N.m)

Time to 4.45 Newton increase (min)

Time to 223 Newton increase (min) Post-hardened (22 h at 260 ° C)

Tensile strength (kg / cm2)

Module (kg / cm2)

Elongation at break (%)

permanent deformation (72 h at 200 ° C) (%)

Table 5

approach

Copolymer

Soot

MgO

Ca (OH) 2

2,2-bis (p-OH-phenyl) hexafluoropropane

Hexamethylenediamine carbamate

Triphenylbenzylphosphonium chloride

Tetrabutyl ammonium captate

Tributyl allyl phosphonium chloride

Tributyl phosphate

Triphenylphosphine oxide

Table 6 approach

Rheometer 175 ° C "3 °, 1.66 Hz torque, minimum (N.m)

Torque, 12 min (N.m)

Time to 4.45 Newton increase (min)

Time to 223 Newton increase (min) Post-hardened (22 h at 260 ° C)

Tensile strength kg / cm2 modulus kg / cm2 elongation at break (%)

Hardness (Shore A2)

permanent deformation (72 at 200 ° C) (%) k.H. = no hardening

9

10th

11

12

13

14

15

16

100

100

100

100

100

100

100

100

30th

30th

30th

30th

30th

30th

30th

30th

3rd

3rd

3rd

3rd

3rd

3rd

3rd

3rd

6

6

6

6

6

6

6

6

2nd

2nd

2nd

2nd

2nd

2nd

2nd

2.4

0.6

0.6 1

0.6

1

0.6

0.6

0.6

0.6

0.4 1

-

-

1

1

0.5

0.25

-

-

1

-

9

10th

11

12th

13

14

15

16

0.8

0.9

1.6

1.2

1.4

1.3

0.8

0.8

12.0

11.6

9.5

10.2

10.6

10.8

10.1

11.9

5.0

3.9

2.5

3.1

2.7

3.2

4.4

4.8

7.4

5.0

4.1

4.5

4.5

4.9

6.8

7.2

151

148

152

132

156

151

160

76

63

61

63

64

58

72

180

185

215

185

220

200

185

17.5

17.3

21.2

20.5

20.0

17.0

15.9

17th

18th

19th

20th

21st

22

23

24th

25th

26

27th

100

100

100

100

100

100

100

100

100

100

100

30th

30th

30th

30th

30th

30th

30th

30th

30th

30th

30th

3rd

3rd

3rd

3rd

3rd

10th

10th

3rd

3rd

3rd

3rd

6

6

6

6

6

-

-

6

6

6

6

2nd

2nd

2nd

-

-

-

-

2nd

2nd

2nd

2nd

-

-

-

-

-

1.5

1.5

-

-

-

-

0.6

-

-

1

1

-

-

-

-

-

0.6

0.4

0.4

-

-

0.4

-

-

1

1

1

1

1.5

1

1

1

17th

18th

19th

20th

21st

22

23

24th

25th

26

27th

0.9

1.0

1.0

16

1.5

1.5

1.4

1.0

1.1

1.5

1.0

10.6

1.0

1.1

2.4

2.4

5.4

6.0

12.1

11.8

U, 1

10.6

5.7

24.0

15.0

3.5

3.6

2.5

2.0

4.7

4.0

3.1

4.0

8.0

k.H.

k.H.

k.H.

k.H. 12th

12th

6.9

5.6

4.5

6.0

140

121

111

136

132

135

147

51

-

-

-

-

40

56

77

72

68

55

190

-

-

-

-

220

170

150

145

195

190

75

-

-

-

70

71

80

82

75

77

17th

-

-

-

45

44

26

28

22

17th

382

10th

Table 7

approach

Copolymer

Soot

MgO

Ca (OH) 2

2,2-bis (p-OH-phenyl) hexafluoropropane triphenylbenzylphosphonium chloride tributyl phosphate trioctyl phosphate

Diethoxy hexylamino phosphorus oxide

Triphenylphosphine oxide

Tris (2-chloroethyl) phosphate

Tricresyl phosphate

Diethyl hexyl phosphate

Tris (N-ethyl-perfluorooctane sulfone

amidoethyl) phosphate

Tributyl phosphine oxide

Table 8 approach

Rheometer 175 ° C, 3 1.66 Hz torque, minimum (N.m) torque, 12 min (N.m)

Time to 4.45 Newton increase (min)

Time to 223 Newton increase (min) Post-hardened (22 h at 260 ° C)

Tensile strength (kg / cm2)

Module (kg / cm2)

Elongation at break (%)

Hardness (Shore A2)

permanent deformation (72 h at 200 ° C) (%)

28

29

30th

31

32

33

34

35

36

37

100

100

100

100

100

100

100

100

100

100

30th

30th

30th

30th

30th

30th

30th

30th

30th

30th

3rd

3rd

3rd

3rd

3rd

3rd

3rd

3rd

3rd

3rd

6

6

6

6

6

6

6

6

6

6

2nd

2nd

2nd

2nd

2nd

2nd

2nd

2nd

2nd

2nd

0.6

0.6

0.6

0.6

0.6

0.6

0.6

0.6

0.6

0.6

-

1

- - - - - - 2 -

_______ i

28

29

30th

31

32

33

34

35

36

37

0.73

1.0

0.73

1.35 1.0

1.1

0.79

0.85

0.79

0.85

10.8

10.5

11.2

10.2

9.7

10.0

11.2

10.9

10.4

10.7

5.3

4.9

4.2

2.7

3.7

3.4

4.1

4.5

4.8

2.4

8.0

5.8

5.8

4.4

5.6

5.1

6.0

6.6

7.5

3.8

128

147

152

144

146

146

137

140

135

137

62

60

71

74

63

58

65

60

51

61

195

190

170

175

207

200

170

185

205

195

80

75

76

77

76

74

75

75

75

75

16.1

16.5

18.5

25.0

17.5

25.0

28.0

18.8

17.8

24th

Claims (5)

626 382 PATENT CLAIMS 1. A process for the vulcanization of elastomeric copolymers of vinylidene fluoride and at least one terminally unsaturated fluorinated monoolefin as a comonomer which, as a substituent, apart from fluorine has at most chlorine or a fluorosalkoxy group with 1 to 4 carbon atoms and at least 1 fluorine atom has atoms on each of the two double-bonded carbon atoms, at least 10% of the carbon atoms in the chain of the copolymer being present as -CH2 groups, by heating under pressure of a mixture containing such a copolymer and also per 100 parts by weight of this copolymer 0.1 to 5 parts by weight of quaternary ammonium or phosphonium compound, 0.2 to 5 parts by weight of aromatic hydroxy or amino compound and 3 to 40 parts by weight of at least one acid acceptor, characterized in that the i5 mixture additionally 0.2 to 5 parts by weight of one Compound of the formula (RO) 3PO, (RO) 2 (RNH) PO, (R) 3PO, (R) 2SO or (R) 2S02, wherein R is optionally for one substituted, optionally containing heteroatoms alkyl, cy-cloalkyl or aryl radical which is free from strongly acidic and strongly 20 basic substituents and has 1 to 20 C atoms, or two R together mean an alkylene group, and that one Mixture heated to 95 to 230 ° C for 30 s to 15 h under a pressure of 7 to 210 Kg / cm2 and then post-cured at 150 to 315 ° C for up to 50 h. 25th 2. The method according to claim 1, characterized in that that a compound of the formula (R) 2SO or (R) 2S02 is used. 3. The method according to claim 1, characterized in that a compound of the formula (RO) 2 (RNH) PO or 30 preferably a compound of the formula (R) 3PO or (RO) 3PO is used. 4. Process according to claims 1 to 3, characterized in that magnesium oxide and calcium hydroxide are used as acid acceptors. 35 5. Process according to Claims 1 to 4, characterized in that 2,2-bis (p-hydroxyphenyl) hexafluoropropane is used as the aromatic hydroxy compound. 40