CH643587A5 - Curable composition for thermally stable adhesive bonds, seals and coatings - Google Patents

Description

The invention relates to curable compositions for thermally resistant bonds, seals and Be-20 layers.

Adhesives and sealants based on acrylates (e.g. methacrylates), which are polymerizable monomers with the aid of radical-forming initiators, are known. Anaerobic compositions are also known (see, e.g., U.S. Patents 2,895,950,3,043,820 and 3,218,305). Anaerobic masses are characterized by their ability to remain liquid in the presence of air, but to cure in the absence of air while achieving a strong adhesive bond. The latter is e.g. the case when you put together 30 matching screws and nuts on which the adhesive has been applied.

The best anaerobic adhesives include those based on urethane or urea acrylate monomers (see e.g. U.S. Patent 3,425,988). These substances are to be regarded as the reaction product of a polyisocyanate (e.g. tolylene diisocyanate) with a monoacrylate (e.g. hydroxypropyl methacrylic acid) which has a reactive hydrogen atom in the alcohol part of its molecule.

Recently, various other urethane-acrylate-type and urea-acrylate-type products that can be used beyond anaerobic 40 curing compositions have been developed. One of these products (cf. DE-OS 2 604 060) consist of a polybutadiene polyol or polyamine with urethane-acrylate or urea-acrylate end groups. Other similar products (see U.S. Patent Application No. 557,740, filed March 12, 1975) are a urethane-acrylate or urea-acrylate end-capped polyalkylene ether polyol. In U.S. Patent Application No. 557,564 (filed on March 12, 1975) yet another similar product is described which has a urethane-acrylate or urea-acrylate end group, for example represents vinyl-grafted polyalkylene ether polyol.

50 ...

55

60

The products described in US Pat. No. 3,425,988 and DE-OS 26 04 060 have the great advantage that they result in “structurally stable” adhesive bonds when cured. The products known from US Pat. No. 3,425,988, however, have the disadvantage above all that they lose their strength in the hardened state when subjected to prolonged exposure to elevated temperatures (for example of 121 ° C. or above). The products described in DE-OS 26 04 060 have a considerably higher heat resistance, but they do not fully meet all purposes.

65 U.S. Patent Application No. 513,609 (filed October 10, 1974) describes the use of additives with maleimide and nadic end groups (nadic anhydrides = 3,6-endomethylene-l, 2,3,6-tetrahydro-cis -phthalic anhydride) to improve the high temperature behavior of

643 587 4

ethoxylated bisphenol A dimethacrylate and alkylene glycol diacrylates of the general formula below:

H0C = C-C-0- • r '

2 m in which the radicals R are each hydrogen, a lower alkyl radical having 1 to 4 carbon atoms, a hydroxyalkyl radical having 1 to 4 carbon atoms or a radical of the general formula below

O

II

-ch2-o-c-c = ch2

R '

mean the radicals R 'are each hydrogen, halogen or a lower alkyl radical having 1 to 4 carbon atoms, the radicals R "each represent hydrogen, the hydroxyl group or a radical of the general formula below

O

II

20th

-o-c-c = ch2

I.

R '

35

mean, m is an integer of at least 1 (e.g. from 1 to 8 or more, preferably from 1 to 4), n is an integer of at least 1 (e.g. from 1 to 20 or more) and p is 0 or 1. However, the teaching of the aforementioned US 40 patent application does not extend to urethane acrylates and urea acrylates and contains no indication of the particular advantages which can be achieved with these monomers.

It was an object of the invention to provide an adhesive, sealing and coating composition with considerably improved strength at elevated temperatures and improved resistance to thermal degradation as well as generally improved room temperature properties. 50

The inventive solution to the problem consists in the curable adhesive, sealing and coating composition characterized in claim 1.

Advantageous embodiments of the invention are shown in the dependent claims. 55

To seal gaps between surfaces or glue surfaces, a composition according to the invention can be applied to at least one of the surfaces and the surfaces can then be kept in mutual contact until the composition has hardened. so

The invention is explained in more detail below with the specification of exemplary embodiments.

A wide variety of urethane-acrylate or urea-acrylate end groups having monomers or prepolymers are suitable as polymerizable substances for the compositions according to the invention. The latter are to be understood as polymerizable substances which are produced by reacting a wide variety of polyols or polyamines

; Polyisocyanates can be obtained. For the purposes of the invention, the term “acrylates” includes methyl, ethyl and halogen homologues.

Monomers and prepolymers

The preferred monomers and prepolymers are mentioned in US Pat. No. 3,425,988 and in DE-OS 26 04 060 and will be described in more detail below.

The monomers mentioned in US Pat. No. 3,425,988 are prepared from monofunctionally substituted alkyl or aryl esters of acrylic acid or methacrylic acid in which the functional substituent has an active hydrogen atom. These monofunctional starting materials containing acrylate end groups are reacted with an organic polyisocyanate in such proportions that all the isocyanate groups are converted into urethane or urea groups. Preferred monofunctional alkyl and aryl acrylates are the acrylic and methacrylic esters which have an alcoholic hydroxyl or non-tertiary amine group. Suitable esters have the general formula below

RsO

I II

H, -C = C-C-0-R6-X-H,

R2

I.

in which X is -O- or -N- (where R2 is hydrogen or a lower alkyl radical having 1 to 7 carbon atoms), R5 is hydrogen, chlorine, methyl or ethyl and R6 is a divalent organic radical in the form of a lower alkylene radical with 1 means up to 8 carbon atoms or a phenylene or naphthylene group. A suitable reaction of the aforementioned functional groups with a polyisoxy anate gives a monomer of the general formula below which is suitable as component a in the composition according to the invention

R50 O

I II II

H2C = C-C-0-R6-X-C -NH

r> B

in which n 'is an integer from 2 to 6, B is a polyvalent organic radical from the group of substituted or unsubstituted alkyl, alkenyl, cycloalkyl, cycloalkenyl, aryl, aralkyl, alkaryl and heterocyclic radicals mean and R5, R6 and X each have the meaning given above.

Specific examples of esters which contain hydroxyl or non-tertiary amine groups and are suitable for the preparation of the above-mentioned monomers are acrylic acid hydroxyethyl ester, methacrylic acid hydroxyethyl ester, methacrylic acid amino

5,643,587

contains ethyl ester, methacrylic acid 3-hydroxypropyl ester, methacrylic aliphatic rings. In the case of several amino acid propyl esters, hydroxyhexyl acrylates, meth- ods, these should either be in the form of condensed tert-butylaminoethyl rinacrylic acid and methacrylic acid genes or via the smallest possible number of carbon hydroxyoctyl esters. Substance atoms (e.g. 1 to 2 for linear and 1 to 8 for branched

In the following, the polyisocyanates, which are linked to one another to form groups 5 or heteroatoms, will be the position of the aforementioned monomers and others, so that the segments have at most a slight bending-suitable composition of suitable monomer. Under a "flexible" segment is a rer and prepolymers can serve, described in more detail. The segment containing Z described here is to be used. The organic polyisocyanates which are preferably used are available. The flexible part can have functional substituents, such as the higher alkenyl diisocyanates, the cycloalkenyl diisocyanates aromatic, heterocyclic or cycloaliphatic group anates and the aromatic diisocyanates with more than 8 (vorpen; branchings can also be present, preferably 15 to 30) Carbon atoms, such as octamethylene - provided that neither the required flexible nature of the diisocyanate, durene diisocyanate (1,2,4,5-tetramethylbenzene segment nor the properties mentioned diisocyanate) or 4,4'-diphenyl diisocyanate are impaired. of the cured resin deteriorate.

The proportions of the reaction components can be varied up to 15%. Specific examples for certain degrees for the preparation of such prepolymers; Polyisocyanates which are generally preferred are phenyl diisocyanate, but toluene is added with equivalent proportions of the reactants ylene diisocyanate, diphenyl-4,4'-diisocyanate, diphenylene meth to a slight excess of polyisocyanate, e.g. an-4,4'-diisocyanate, dianisidine diisocyanate, naphthylene-1,5-nem excess polyisocyanate of 1 equivalent. A diisocyanate, diphenyl ether-4,4'-diisocyanate, p-phenylene diiso “equivalent portion” is to be understood as the amount which 20 cyanate, dicyclohexylmethane-4,4'-diisocyanate, 1,3-bis (isocy-a Isocyanate group per hydroxyl or non-tertiary amine anatomethyl) cyclohexane, cyclohexylene diisocyanate, tetra group provides. chlorophenylene diisocyanate, 2,6-diethyl-p-phenylene diisocyanate

The reactions can be carried out in the presence or absence of anate and 3,5-diethyl-4,4'-diisocyanatodiphenylmethane. Of diluents. Previously usable polyisocyanates are the higher molecular weight diluents, such as hydrocarbons, which have rigid molecular weight, which are, for example, aliphatic, cycloaliphatic or aromatic by reaction of terminal primary and secondary hydrocarbons, e.g. Benzene, toluene, cyclohexane, polyamines containing amino groups or of polyvalent hexane or heptane. However, other dilute alcohols, for example the alkane, cycloalkane, such as methyl isobutyl ketone, diamyl ketone, isobutene-alkene or cycloalkene polyols, such as glycerol, ethylene glycol methyl methacrylate or cyclohexyl methacrylate, can be successfully mixed with 30 kol, bisphenol A or substituted bisphenol-A, with one turn, especially if total compatibility with the excess of any of the aforementioned isocyanate composition is sought. will hold. This has a higher molecular weight. The reaction temperature can also be within a broad range of urethane and urea polyisocyanates. For example, if chemically equivalent general formula below, amounts of the reactants or a minor 35

Applying excess isocyanate, you can at Tempera- H O

tures from room temperature or below (e.g. 10 to 15 ° C) r lll_.

work up to the range of 100 to 175 ° C. With Ver IO = C = N-R'-N -C -Xj-n-B

Using simpler isocyanates, the components are preferably combined at or near room temperature, such as an organic radical in the R1 in the group of the substi range from 20 to 30 ° C. In the production of isocyanate adducts with cycloalkenyl, aryl, aralkyl and alkaryl radicals with 2 to 20 high molecular weight with an isocyanate-over-substituted or unsubstituted alkyl, alkenyl, cycloalkyl, shot, the reaction compo carbon atoms can be represented and X, B and n 'each mix the previous at room temperature; preferably have the meaning given in a standing position.

but the approach to temperatures from 40 to about 45 The diisocyanate is, as mentioned, preferably with egg-150 ° C. In the temperature range from 90 to 120 ° C, a smooth, stiff segment in the form of an aromatic, ter reaction sequence is guaranteed. heterocyclic or cycloaliphatic compound with

Products which can be used for compositions according to the invention as at least two active hydrogen atoms, preferably egg component a, can be reacted as polymeric diamine and in particular a diol. Addable one-component block copolymers (prepolymers for suitable compounds are 2,2- (4,4'-dihydroxydisates) with rigid and flexible segments. Phenyl) -propane (ie bisphenol-A), 4, 4'-Isopropylidendicy-They are obtained by linking starting prepolyclohexanol (ie hydrogenated bisphenol-A), ethoxylated bis-merisates which contain phenol-A, propoxylated bisphenol-A, 2,2- (4 , 4'-dihydroxy (eg methacrylate end groups). Preferred diphenyl) butane, 3,3- (4,4'-dihydroxydiphenyl) pentane, instructions can accordingly be given to a "flexible" polymeric alkylene 55 (4th , 4'-Dihydroxydiphenyl) -p-diisopropylbenzene, 1,3-Cyclohe-ätherdiol segment with a relatively low molecular weight xandiol, 1,4-Cyclohexanediol, 1,4-Cyclohexanedimethanol, bi-with one with regard to its hydroxyl equivalent cyclic and tricyclic Diols, such as 4,8-bis (hydroxymethyl) gene isocyanate equivalent of a “stiff” diisocyanate, such as Totricy clo [5.2.1.02'6] decane, 2,2,4,4-tetramethyl-l, 3-cyclobutane-luylene diisocyanate or methylene diisocyanate (diphenylmethylene, hydroquinone, resorcinol, 2,2- (4,4'-dihydroxydiphenyl) -an-4,4'-diisocyanate), with the formation of urethane bond 60 sulfone and 4,4'-oxydiphenol and halogen derivatives of these genes. Before the reaction, compounds such as tetrabrominated ethoxylated bisphe with the diol are preferably mixed with the diisocyanate in excess with a further ol-A. The aforementioned cyclic compounds can ren rigid component, which has at least two active water - also substituted by other reactive or non-reactive radicals, such as atoms in hydroxyl or non-tertiary amine groups g5 alkyl radicals having about 1 to 4 carbon atoms, to react, whereby the other be stiff. Depending on the specific reaction component, the reaction can be capped with isocyanate end groups. Uncomponents at temperatures from room temperature to a “rigid” segment are understood to be a segment or approximately 180 ° C., preferably from approximately 40 to 120 ° C., continuous segments which are aromatic, heterocyclic or cyclo-. At lower temperatures, the

643 587

using conventional catalysts may be appropriate.

If necessary, non-reactive diluents can be used.

The organic polyisocyanate, optionally reacted as described above, is reacted with a polymeric compound 5 which has a functional group having a reactive hydrogen atom (preferably in a hydroxyl group) at each chain end.

The preferred polymeric compounds include polybutadiene or copolybutadiene polyols. Although the reactions can take place on both the 1,2- and the 1,4-configuration of butadiene, the latter configuration is highly preferred since it leads to superior properties after curing in the compositions according to the invention. The polybutadiene or copolybutadiene used should therefore be present in the 1,4 configuration to more than about 50% (preferably at least 70%, in particular at least 80%). Such substances are produced by conventional methods; numerous suitable materials are commercially available.

The 1,4 portion of the butadiene diols used has the general formula below

20th

Ha <CH2-CH = CH-CH2 ^ C H-CH2 \

I.

T

OH

n3

25th

in which a can be 0.65 to 1.0 (preferably 0.75 to 0.85), b 0 to 0.35 (preferably 0.25 to 0.15) and n3 5 to 150 (preferably 10 to 85) and T is hydrogen or an organic radical derived from compounds such as styrene or its simpler derivatives, lower alkyl esters of acrylic acid or methacrylic acid or acrylonitrile (which is particularly preferred). The rest T should of course be chosen so that it does not significantly impair the properties conferred by the rest of the molecule. If b is not 0, the proportion of comonomer residue 40 (to which b refers) should make up less than 40% by weight (preferably less than 30% by weight) of the total copolymer.

Further preferred polymeric compounds which can be reacted with the polyisocyanate product are polyether or copolymer ether compounds of the general formula below

Court

R3 R4 CH2) xO- ^ r (C H-CH-0) -

50

H, n4

60

in which x is an integer from 1 to 8, y is an integer from 0 55 to 20, z 'is an integer from 0 to 10 and n4 is an integer from 1 to 100. Preferably x is 2 to 6, y 1 to 5, z '0 to 2 and n4 is 3 to 60. In particular, x 4 to 6, y is 1 or 2, z' 0 or 1 and n4 is 5 to 40. R3 and R4 can Hydrogen, lower alkyl radicals with 1 to 3 carbon atoms, cycloaliphatic radicals, cycloalkenyl radicals, aromatic radicals with up to 8 carbon atoms or heterocyclic radicals with up to 8 carbon and / or hetero atoms. In order to achieve a high degree of flexibility in the segment, it is also very expedient if the glycol is linear. Specific examples of suitable linear polyols are poly-tramethylene ether glycol and polyethylene ether glycol. Specific examples of branched polyols are poly-1,2-propylene

ether polyol and poly-1,2- or 1,3-butylene ether glycol. The manufacture and properties of polyols of this type are known from the literature, e.g. J. H. Saunders and K.C. Frisch, "Polyurethanes-Chemistry and Technology", Interscience, New York, N.Y. (1963).

Further preferred polymeric compounds which can be reacted with the polyisocyanate product are graft polymers with polyalkylene ether polyol backbones which have been grafted with olefinically unsaturated monomer. These are preferably graft polymers in which vinyl monomers or polymers have been grafted onto the polyalkylene ether polyol backbones. These graft polymers have the general formula below

HO (R3'-0-M-R4'-0 H

Q'q in which R3 'and R4' are alkylene or alkylidene and / or branched alkylene or alkylidene radicals having 2 to 10 (preferably 3 to 6) carbon atoms, Q 'is a monomeric or polymeric or copolymeric radical which is a linear radical or branched alkyl, alkenyl, alkynyl, aromatic, cycloaliphatic or heterocyclic radical with 2 to 12 (preferably 4 to 10) carbon and / or heteroatoms, and x 'can be 0 to 200 (preferably 10 to 100), y '1 to 100 (preferably 1 to 50) and q 1 to 400 (preferably 1 to 200). The preferred radicals Q 'are derived from acrylonitrile, styrene, methyl methacrylate, vinyl acetate, ethyl acrylate, vinyl chloride or vinylidene chloride, with acrylonitrile and styrene being particularly preferred. The preferred alkylene ether residues are derived from 1,2-propylene oxide, ethylene oxide and tetramethylene oxide. The olefinically unsaturated graft monomer includes permanent unsaturated bonds (e.g. CH2 = CH-), polyvinyl derivatives (e.g. CH3- (CH2) -q) and copolymeric vinyl derivatives (e.g. copolymers of acrylonitrile and / or butadiene).

The aforementioned graft polymer segments and their manufacture are by Kuryla et al. in Journal of Cellular Plastics, "Polymer / Polyols, a New Class of Polyurethane Intermedia-tes" (March 1966) and by Frisch et al. in "Advances in Ure-thane Science and Technology" (1971), Volume 2, page 9 ff., Technomic Publishing Co., Inc., Westport, Connecticut. The graft polymer segments are typically prepared by in-situ polymerization of an olefinically unsaturated monomer, such as a vinyl monomer, in a polyol solution, producing a fine, usually fairly stable, dispersion of the polymer in the polyol. The so-called. "Polymer / polyols" are available in the form of dispersions from Union Carbide Corp., New York, N.Y. (under the trademark "Niax" Polyol), and marketed by BASF - Wyan-dotte Corp., Wyandotte, Michigan (under the trademark "Pluracol").

The preparation of the polymer / polyol dispersion generally consists in gradually introducing 1 part of grafting monomer at a temperature of at least 80 ° C with stirring into a mixture of 4 parts of polyol and about 0.05 part of peroxy initiator (e.g. benzoyl peroxide). The unreacted graft monomer can then be removed by vacuum stripping. However, the working conditions mentioned are not to be interpreted in a restrictive sense; rather, the correct proportions and reaction conditions differ depending on the particular materials used and can be determined routinely by a person skilled in the art.

The aforementioned polymer / polyols consist of a mixture of two reactive substances, i.e. the grafted

643 587

ten polyol and the ungrafted polyol, as well as polymer of olefinically unsaturated monomer used for grafting (e.g. polyacrylonitrile). Although the grafted polyol can be separated from the dispersion as a solid substance by conventional solvent methods, this is not necessary for the preparation of the prepolymers used according to the invention. However, the polymer / polyol dispersion mixture is preferably used in the reaction, since it results in a prepolymer which is both “filled” (due to the solid grafted resin) and “plasticized” (due to the polyol). If the grafted polyol is separated off, it can of course subsequently be dispersed again in a suitable (preferably inert) solvent in order to convert it into the prepolymers used according to the invention.

The viscosity of the polymer / polyol dispersions used for compositions according to the invention is within a wide range, which typically ranges from 500 to 10,000 cps (measured at 25 ° C. using an RTV Brookfield viscometer). Although the viscosity is not to be regarded as a critical parameter for the subsequent preparation of the prepolymer, dispersions with the lower viscosity values within the aforementioned range (i.e. from 500 to 4000 cps, measured as mentioned) are preferred, since these lead to prepolymers with correspondingly low viscosities. The latter have a clear advantage in certain prepolymer applications (e.g. as an adhesive for attaching a bearing to a shaft).

The aforementioned various polymeric compounds having functional groups having an active hydrogen atom are each reacted in a ratio of more than one isocyanate equivalent of polyisocyanate per H group equivalent of compound. In this way, a product is obtained which has an isocyanate group at each end of the polyol or polyamine segment. The molar excess of the polyisocyanate can be 0.05 to 6.

The reaction can be carried out in the temperature range from room temperature to 150 ° C., preferably from 40 to 120 ° C. After the flexible diol has been added, the reaction proceeds completely in the preferred temperature range for 0.1 to 30 hours. If required, the reaction can also be carried out in the presence of catalysts and non-reactive diluents can be used for viscosity control.

The product obtained in the aforementioned reaction is reacted with acrylic acid or methacrylic acid ester, which has a hydroxyl or a non-tertiary amine group in the molecule, in the quantitative ratio of at least one mole of ester to one isocyanate equivalent, based on the isocyanate group content in the molecule. This gives a prepolymer which is capped at both ends with functional acrylate or methacrylate groups. Esters which can be used to prepare prepolymers for compositions according to the invention have the following general formula r5 o

I II

h2c = c-c-o-r5-x-h in which X, R5 and R6 each have the meaning given above.

Specific examples of suitable substances containing hydroxyl or non-tertiary amine groups are acrylic acid-io hydroxyethyl ester, methacrylic acid hydroxyethyl ester, meth-acrylic acid amino ethyl ester, methacrylic acid-3-hydroxypropyl ester, methacrylic acid aminopropyl ester, acrylic acid hydroxyl ester, methacrylate methacrylate-methyl methacrylate-methyl methacrylate. The Mo-15 noacrylic acid or monomethacrylic acid esters of bisphenol-A, the fully hydrogenated derivative of bisphenol-A and cyclohexanediol, etc. are also suitable.

The reaction can be carried out in the presence or absence of diluents. Diluents such as hydrocarbons, e.g. aliphatic, cycloaliphatic or aromatic hydrocarbons, such as benzene, toluene, cyclohexane, hexane or heptane. However, other diluents, such as methyl isobutyl ketone, diamyl ketone, isobutyl methacrylate or cyclohexyl methacrylate, can also be used successfully, if necessary, particularly when complete compatibility with the curable composition is sought.

30 The reaction temperature can also be within a wide range. If the reaction components are combined in approximately equivalent proportions, it is possible to work in the range from room temperature or below (for example at 10 to 15 ° C.) up to temperatures of 100 to 180 ° C. If the simpler ones are used in the reaction Isocyanate adducts starts, the reactants are preferably mixed at or near room temperature (as at 20 to 30 ° C). A catalyst is preferably used at the lower reaction temperatures. If the 40 isocyanate adducts with a higher molecular weight are used, the reaction is preferably carried out at higher reaction temperatures (e.g. at 40 to 150 ° C).

The adducts 45 having acrylate end groups 45 used according to the invention can also be produced by processes other than that described above. For example, the polyisocyanate compound can be reacted with a suitable hydroxyacrylate and the adduct obtained can be reacted further with a suitable polymer having the required 30 reactive hydrogen.

The following general formula can be given for the finished urethane-acrylate or urea-acrylic prepolymers prepared from the above-mentioned polyols and polyamines of DT-OS 2 604 060 and usable according to the invention:

R 0 0 0 0 0

CH2 = C -C-0-R6-Q- (C-NH-I-NH-C-D-) nC-NH-I-NH-C

--Z

(I)

C-NH-I-Y-0 / m-2

643 587

8th

which is a partial formula in the case that n = 1 and m is greater than 2, in which n has the value 0 or 1,

m is an integer greater than 1, which is equal to the valence of D,

z is an integer greater than 1, which is equal to the valence of Z,

R5 corresponds to the above meaning hydrogen, chlorine, methyl or ethyl,

R6 as defined above is an alkylene group with 1 to 8 carbon atoms or a phenylene or naphthylene group,

Q is an oxygen atom or a group as it results when one or the amine hydrogen atom is removed from a primary or secondary amino group,

I an organic residue,

D is an m-valent radical as it results when, in the case of an aromatic, heterocyclic or cycloaliphatic poly-ol molecule which has a number m of hydroxyl groups esterifiable with acid, the hydrogen atom is removed from each of these hydroxyl groups, or an m-valent group Residue as it results when, in the case of an aromatic, heterocyclic or cycloaliphatic polyamine molecule which has a number m of acylatable amine groups, an amine hydrogen atom is removed from each of these amine groups,

Y is a urethane or urea group whose atom bonded to I is an N atom to which an H atom is bonded,

and Z is a z-valent radical as it results when z is removed from a molecule of a polymeric or copolymeric polyol z hydrogen atoms belonging to z with acid esterifiable hydroxyl groups, or a z-valent radical as it results when from one Molecule of a polymeric or copolymeric polyamine z Amine hydrogen atoms belonging to z acylatable amine groups are removed.

The meaning given for I above also includes those organic radicals which contain isocyanate groups added to urethane or urea groups.

If the urethane-acrylate or urea-acrylate prepolymers are made from diisocyanates, the following simplified general formula can be given for them:

RsO

I I!

CHT = C -C-OR6 * 1

'* d'n * i'i *) z-z'

in which the asterisks (*) indicate urethane bonds (-NH-COO-) or urea bonds (-NH-CO-NH-), I 'represents the remainder of a diisocyanate from which the isocyanate groups have been removed, D' represents a remainder of an aromatic one , io heterocyclic or cycloaliphatic polyol or polyamine (preferably a diol, in particular a diol of a cycloaliphatic or aromatic compound), Z 'is a radical of a polymeric or copolymeric polyol or polyamine, z' is determined by the valence of Z ' is an integer, n is 0 or 1 and i is 0 if d is 0 and otherwise corresponds to the reduced number of reactive hydrogen atoms of the polyol or polyamine having the radical D ', and R5 and R6 each have the meaning given above .

20th

The term “urethane or urea acrylate” used with regard to the prepolymers of DE-OS 26 04 060 or US Pat. No. 3,425,988 refers to any polymerizable substances with acrylate end groups (for example 25 methacrylate end groups) in which any acrylate

RsO

I II

group (i.e., CH2 = C-C-O-R6- in the formulas presented above) is linked to the rest of the molecule via a urethane or urea bond 30 and to the functionality of such a group.

35 Thermal additive

In addition to the monomers and prepolymers described above, the compositions according to the invention contain an additive which is provided with “maleic imide or Nadic end groups (Nadic anhydride-40 = 3,6-endomethylene-1,2,3,6-tetrahydro-cis phthalic anhydride) and has one of the following general formulas:

NO'

0

n-r8-n

0

NO'

N-R8-N

The exact type of R7 and R8 is not essential; these are any organic residues which do not contain any groups which impair the suitability of the compositions for the intended purposes. In general, the radicals R7 and R8 can be alkyl, cycloalkyl, 5 aryl, aralkyl or alkaryl radicals; each of these radicals can be extraordinarily long-chain and have, for example, up to about 200 (or more) carbon atoms. The radicals preferably contain 6 to 100 carbon atoms, in particular 6 to 50 carbon atoms. The residues R7 and R8 can furthermore have ether bonds as well as sulfur and nitrogen bridges. In addition, the radicals R7 and R8 can have branches and can be substituted by halogen atoms or lower alkyl radicals having 1 to 6 carbon atoms. R7 and R8 can also be heterocyclic radicals. 15

The advantages of the compositions according to the invention appear to be mainly due to the unsaturation of the imide ring. Therefore, both R7 and R8 can be relatively complex residues, provided

that they have no functional groups that impair the usage behavior of the additive. The suitable concentration range for the additive is 1 to 80% by weight, preferably 5 to 50% by weight, in particular 5 to 35% by weight (in each case based on the total mass).

The additives used according to the invention can be prepared in accordance with US Pat. No. 3,562,223. Typical examples of such additives are those under the trademarks "Keramid" and "M-3" from Rhodia, Inc., New York, N.Y. and «HVA-2» by E.I. du Pont de Nemours & Co., Wilmington, Delaware. Preferred additives are the bis-maleimide of m-diamino-benzene, the bis-maleimides of the various methylenediamines and the reaction products of diamines with a molar excess of bis-maleimides. The following compounds are particularly preferred: 35

0

0

(I) (m-phenylenedimaleinimide)

40

45

0 0

(II) (bis-maleimide of methylenedianiline)

55

60

65

643 587 10

Can be applied with the aid of the surfaces connecting the additives used according to the invention. At least four properties of the hardened composition are suitable as primers, the sub-improvements described in US Pat. No. 3,625,930, the type and extent of the improvement appearing, and in particular those described in DT-OS 2,401,744.

nend from the particular monomers used or known thiourea materials. Such primer

Detach prepolymer. The improvements are advantageously made in the form of dilute solutions to make them more resistant to degradation of the surfaces to be joined or to both surfaces.

the perfect binding due to the spraying at elevated temperatures.

occurring oxidation, higher strength of the bond or it may be expedient to carry out the curing polymerization

Seal at elevated temperatures, higher strength to be accelerated by moderate heating (e.g. to 50 to 150 ° C)

Binding or sealing at room temperature and often. At temperatures above 125 ° C the hardening is also improved strength of the hardened material after (without primer) mostly within 10 (or less

Room temperature curing. It is not fully cleared up to complete minutes.

which way the improvement comes about. Without the compositions according to the invention being able to be based on any specific theory, room temperature-curing anaerobic adhesives and sealing ends, the additives used according to the invention for the cleaning agent can be formulated. Preparations of this type are copolymerization with the monomers or prepolymers, etc. in US Pat. No. 3,043,820, where hydroperten, whereby the characteristic for thermal degradation serve as initiators. Such anaerobic masses can see molecular "tear-open effect" is interrupted. The further advantageous polymerization accelerator, such as organi-improvement of the heat resistance, is presumably due to the increase in the mono- or tertiary amines caused by visible imides (eg benzosulfimide) or primary, secondary such copolymerization, as well as inhibitors or stabilizers freezing or glass transition temperature . from the quinone or hydroquinone series. Thieves-

The compositions according to the invention generally contain accelerators in concentrations of a radical-forming polymerization initiator. It is less than 10% by weight, the inhibitors in concentrations can use a wide variety of known peroxy initiators from 10 to 1000 ppm. When formulated as compositions prepared according to an aerobic preparation, they have the advantage of a free radical mechanism of being hard, tough, long-term durability and capable of being cured by room temperature. Examples of suitable initiators for temperature hardening with exclusion of oxygen, such as those in the diacyl peroxides, such as benzoyl peroxide, dialkylper-engaging threads of a screw and the associated oxides, such as di-tert-butyl peroxide, ketone peroxides, such as methyl parent, or between the joined surfaces of ethyl ketone peroxide and easily saponifiable peresters, such as tert-30 of a bearing and the associated axis or shaft on butyl peracetate, tert-butyl perbenzoate or di-tert-butyl di-occurs. The rate of anaerobic curing can be perphthalate. A particularly suitable class of peroxy initiators increased by moderate heating (for example up to 150 ° C.) are the organic hydroperoxides, such as cumene.

hydroperoxide, methyl ethyl ketone hydroperoxide or tert. The following examples are intended to illustrate the invention

Butyl hydroperoxide. Explain 5 of these organic hydroperoxides without, however, restricting them.

cumene hydroperoxide is particularly preferred. The initiators should be used in concentrations of 0.01 to 10% by weight (pre-example 1 preferably 0.1 to 5% by weight), based on the total mass. This example describes two typical anaerobic adhesives. Another suitable class of initiator formulations, in which any of the above are carbonyl-containing UV-activated radical formers, 40 prepolymer resins or mixtures thereof, such as acetophenone, benzophenone and the benzoin ethers. be applied.

Suitable UV initiators are in the United States patent. Ser.

No. 356,679 (filed May 2, 1973). One recipe (a)

can also use mixtures of initiators. 79 g of the respective prepolymer resin solution (solid

The adhesive, sealant and content according to the invention (45% to 75%) can be mixed with coating compositions, if necessary, with 4.6 g of hydroxypropyl methacrylate (co-reactive solvent using reactive diluents, which are used as copotene) with thorough stirring. Subsequently, a suspension of 0.38 g of polymerization with the above-mentioned prepolymers enabled saccharin is stirred into 3.8 g of triethylene glycol dimethacrylate. Typical examples of suitable compounds are then 5.6 g of acrylic acid (adhesion promoter) and thinners are the acrylic acid hydroxyalkyl esters, such as 50 2.8 g of cumene hydroperoxide, and the mixture is stirred, for example, acrylic acid hydroxyethyl or hydroxypropyl ester, and then for a further hour. If required, small amounts of stabilizers, be-recyclohexyl or tetrahydrofurfuryl esters can be used in accordance with the corresponding esters of methacrylic acid, such as methacrylic acid. You can also accelerate, thickeners, plasticizers, etc. use other unsaturated reactive diluents, zen. Various parts of a high temperature are added, for example styrene or acrylonitrile. If one works with diluent 55 according to the examples below, so that working agents are used, their concentration less than 60% of the finished mass should be an additive concentration of 5 to% by weight (preferably 10 to 40% by weight). Have 75%. The high temperature additive is

The curable compositions of the invention are thoroughly stirred for 1 to 24 hours.

can also be prepared as two-component materials. In this case, the initiator or one of the Ini 60 formulation (b)

tiators of an initiator combination a second component. 70 g of the respective prepolymer resin are added, which are mixed with the first (monomeric) component with 23.9 g of hydroxypropyl methacrylate. Then be united at the time of use. You can e.g. within about 1 hour 2.9 g acrylic acid, 2.7 g cumene hy-

the monomer or prepolymer is stirred into one of the compound peroxides and 0.3 g of tributylamine. If necessary, the surfaces and the initiator on the other surface will bring small amounts in accordance with conventional practice and then combine the two surfaces of stabilizers, accelerators, thickeners,

Analogously, an accelerator can be separated as second comm plasticizers, among others. added. You add different attachments

component (e.g. as a primer) on one of the parts of a high temperature additive according to the following

11

643587

Examples are added so that the finished masses have an additive concentration of 5 to 75%. The high temperature additive is thoroughly stirred in for 1 to 24 hours.

Example 2

Anaerobic adhesives according to Example 1 are produced using some of the urethane-methacrylate prepolymers described above and listed in Table I (70 to 75% solutions in 20 to 25% triethylene glycol di-methacrylate). The structure of the prepolymers shown in Table I is explained below on the basis of their preparation.

Prepolymer

A reaction product of 2 moles of hydroxypropyl methacrylate (HPMA) with 1 mole of methylene bis-phenyl isocyanate (MDI).

B mixture of a) a reaction product of 2 moles of a reaction product of HPMA with tolylene diisocyanate (TDI) with 1 mole of hydrogenated bisphenol-A (HBPA) and b) a reaction product of x moles of a reaction product of hydroxyethyl methacrylate (HÄMA) and TDI with a polypropylene oxide polyol in the Ratio a / b of about 2: 1.

s C reaction product of 2 moles of a reaction product of HPMA, TDI and HBPA with 1 mole of a butadiene / acrylonitrile diol.

Prepolymer

10 D reaction product of 2 moles of a reaction product of HPMA, TDI and HBPA with 1 mole of a polytramethylene ether diol with a molecular weight of about 2000.

E reaction product of 2 moles of a reaction product of HPMA and MDI with 1 mole of a polytetramethylene ethene diol with a molecular weight of about 650.

F reaction product of 2 moles of a reaction product of HPMA, TDI and HBPA with 1 mole of a dispersion of a polypropylene oxide polyol onto which a styrene / 20 acrylonitrile copolymer was grafted, in a polypropylene oxide polyol.

Table I prepolymer

A B

C D E F

Recipe (from example 1)

a b

structure

(HPMA) 2 * [MDI]

Mixture of (HPMA * TDI) 2 * [HBPA] and (HÄMA * TDI) x * [polypropylene oxide polyol] in a ratio of 2: 1 (HPMA * TDI * HBPA * TDI) 2 * [P (BD-CN] (HPMA * TDI * HBPA * TDI) 2 * [PTME 2000] (HPMA * MDI) 2 * [PTME 650] (HPMA * TDI * HBPA * TDI) 2 * [Graft-PS-PAN / PPO]

Several physical tests are carried out with the aforementioned masses. The overlap tensile shear test is carried out in accordance with ASTM test standard D-1002-65. In this test, the overlapping areas of two sandblasted steel test strips are glued together. The ends of the connected test strips are then pulled apart using a measuring device (such as an Instron tester) and the tensile shear strength of the bond is determined. The pressure shear test performed in accordance with the U.S. Army Standard MIL-R-46082A (MR) determines the ability of adhesives to secure a cuff or bearing to an axle. In this test, a cylindrical pin is glued into the bore of a matching ring. The force required to press the pin out of the ring is then measured using an In-stron tester or a similar device.

tested. The pins are pressed out of the rings using an Instron tester. Table II shows the pressure shear strength values.

45

Table II

Prepolymer

Compressive shear strength, 9.81-104 N / m2 (psi) room temperature 204.4 ° C (400 ° F)

55

Example 3

This example shows the marked improvement in room temperature strength and heat resistance (at 204.4 ° C.), which are achieved with a mixture of 82 parts of adhesive component and 18 parts of Kerimid-601 (K-601). The masses are applied to steel pins and rings, which are then joined together. The adhesives are then cured at 93.3 ° C. for 1 hour and then allowed to cool to room temperature. Half of the test specimens are at room temperature, the other half after heating for 75 minutes at 204.4 ° C at 204.4 ° C

60

A

239.4

(3405)

78.4

(1115)

A + K-601

318.8

(4535)

127.6

(1815)

B

219.4

(3120)

10.9

(155)

B + K-601

313.6

(4460)

24.3

(345)

C.

254.9

(3625)

70.0

(995)

C + K-601

331.9

(4720)

120.2

(1710)

[111.8 *

(1590 *)]

D

291.8

(4150)

22.1

(315)

D + K-601

320.3

(4555)

39.0

(555)

E

284.4

(4045)

21.8

(310)

E + K-601

321.0

(4565)

62.9

(895)

F

288.3

(4100)

F + K-601

317.1

(4510)

* with 18% m-phenylenedimaleinimide instead of K-601 Example 4

Table III shows the improvement in room temperature curing achieved using conventional primers. Steel pins and rings are primed and then connected with the adhesive, which is then hardened for 24 hours at room temperature.

643 587

12

Table III

Prepolymer

E

E + K-601 F

F + K-601

Dry shear strength, 9.81-104 N / m2 (psi) "Primer T" * "Accelerator 750" *

158.2 (2250)

173.7 (2470)

136.0 (1935)

207.4 (2950)

Table IV prepolymer

124.1 (1765)

149.1 (2120) 95.3 (1355)

204.2 (2905)

Test conditions

♦ Commercial product from LOCTITE CORPORATION, Newington, Connecticut.

Example 5

5 The excellent preservation of the adhesive strength is shown in the case of the addition of K-601 to one of the compositions. Steel pins and rings are connected with the help of the adhesives; curing takes place at 93.3 ° C (200 ° F) for 1 hour. The bonded test specimens are aged at 232.2 ° C (450 ° F), cooled to room temperature and tested.

Compression shear strength, 9.81-104 N / m2 (psi) weeks at 232.2 ° C (450 ° F)

0

1

2nd

3rd

4th

c

Room temperature

255.2

116.4

66.8

28.1

7.73

(3630)

(1655)

(950)

(400)

(110)

204.4 ° C (400 ° F)

49.6

44.3

16.5

15.1

2.46

(705)

(630)

(235)

(215)

(35)

C + 18%

Room temperature

328.0

255.6

153.6

44.6

27.4

K-601

(4665)

(3635)

(2185)

(635)

(390)

204.4 ° C (400 ° F)

91.7

83.7

58.7

30.9

12.7

(1305)

(1190)

(835)

(440)

(180)

Example 6

Tables V and VI provide further evidence for the maintenance of structural strength at high temperatures, which is achieved with the aid of the compositions according to the invention containing an additive (K-601). With «Accelerator 750», primed, overlapped steel scissors are connected with the adhesive and then hardened for 24 30 hours at room temperature. The adhesive consists of 75 parts of prepolymer B (containing about 15% of a butylene glycol adipic acid polyester plasticizer) and 25 parts of K-601.

Table V gap

Duration and temperature of aging

1 week at 176.7 ° C (350 ° F)

2 weeks at 176.7 ° C (350 ° F) 4 weeks at 176.7 ° C (350 ° F) 6 weeks at 176.7 ° C (350 ° F) 8 weeks at 176.7 ° C (350 ° F) F)

1 week at 232 ° C (450 ° F)

2 weeks at 232 ° C (450 ° F)

3 weeks at 232 "C (450 ° F)

4 weeks at 232 ° C (450 ° F)

6 weeks at 232 ° C (450 ° F)

8 weeks at 232 ° C (450 ° F)

3 / 8-16 steel nuts and bolts are glued with the aid of compound A mixed with Kerimid. The test specimens are aged at 204.4 ° C (400 ° F) or 232.2 ° C (450 ° F) during the times shown in Table VI, but are tested at room temperature. Table VI shows the breaking strength in kg.cm (in lbs.). That is under «breaking strength»

Table VI

Duration and temperature of aging

3 days at 206.4 ° C (400 ° F)

1 week at 206.4 ° C (400 ° F)

Tensile shear strength, 9.81-104 N / m2 (psi) 0.0508 mm 0.508 mm (2 mils) (20 mils)

45.0

(640)

73.1

(1040)

33.0

(470)

54.1

(770)

51.1

(725)

49.9

(710)

52.0

(740)

56.2

(800)

47.8

(680)

53.4

(760)

42.1

(600)

52.7

(750

35.2

(500)

41.5

(590)

33.0

(470)

47.8

(680)

30.9

(440)

45.7

(650)

30.9

(440)

42.9

(610)

5.62

(80)

49.9

(710)

to understand the torque required for the first movement between screw and nut. The «prevail strength» is the torque that is required to unscrew the nut by 180 ° C beyond the breaking point.

60

Concentration of K-601,%

0 10 50

305/184 (265/160) 265/156 (230/135)

282/207 (245/180) 276/236 (240/205)

242/173 210/150) 144/202 (125/175)

13

643587

(Continuation)

Table VI

Concentration of K-601,%

Duration of maintenance and

0

10th

50

-temperature

2 weeks at 206.4 ° C (400 ° F)

104/98

156/150

225/265

(90/85)

(135/130)

(195/230)

3 weeks at 206.4 ° C (400 ° F)

92/81

271/144

144/138

(80/70)

(235/125)

(125/120)

3 weeks at 204.4 ° C (400 ° F) +

81/98

138/81

138/86

1 week at 232.2 ° C (450 ° F)

(70/90)

120/70)

(120/75)

3 weeks at 204.4 ° C (400 ° F) +

relaxed

11.5 / 29

23 / 11.5

5 weeks at 232.2 ° C (450 ° F)

(10/25)

(20/10)

3 weeks at 204.4 "C (400 ° F) +

8.1 / 17

40/23

7 weeks at 232.2 ° C (450 ° F)

(7/15)

(35/20)

3 weeks at 204.4 ° C (400 ° F) +

1.15 / 8.1

5.8 / 3.5

9 weeks at 232.2 ° C (450 ° F)

(1/7)

(5/3)

Example 7

The outstanding effect of another additive suitable according to the invention (m-phenylenedimalein imide; HVA-2) on the heat aging properties is shown. Recipe B is used. The adhesive consists of 75 parts B and 25 parts HVA-2. Overlapped steel scissors are connected with the adhesive, hardened for 1 hour at 93.3 ° C (200 ° F), then aged at 204.4 ° C (400 ° F) or 232.2 ° C (450 ° F) and finally tested at room temperature. The results are shown in Table VII.

20th

25th

Table VII Duration

1 week

3 weeks

4 weeks

5 weeks

Tensile shear strength, 9.81-104 N / m2 (psi) 204.4 ° C (440 ° F) 232.2 ° C (450 ° F)

78.7 (1120)

48.5 (690)

58.3 (830)

59.4 (845)

45.0 (640)

31.6 (450)

25.3 (360)

9.84 (140)

Example 8

The effect of increased concentrations of an additive suitable according to the invention (m-phenylenediamineimide) on the heat resistance (204.4 ° C. or 400 ° F) is shown. Overlapped steel scissors are connected with an adhesive based on formulation B, which contains 0 to 50% dimaleinimide. Curing initially takes 1 hour at 93.3 ° C (200 ° F), after which the test specimens are balanced at 204.4 ° C (400 ° F) and their tensile shear strength is tested at this temperature. The results are shown in Table VIII.

Table VIII

Tensile shear strength at 204.4 ° C (400 ° F) 9.8 MO4 N / m2 (psi)

Concentration of HVA-2,% 0 25 30 35

1.76 (25)

27.8 (395)

32.0 (455)

39.4 (560)

40

45

111.4 (1585)

50

137.8 (1960)

253.6 (2185)

C.

Claims (17)

643 587 PATENT CLAIMS 1. Curable composition for thermally resistant bonds, seals and coatings, characterized by a mixture of a) urethane or urea acrylate with a plurality of acrylate urethane or urea groups, such as result when an isocyanate group is present a hydroxyl or acylatable amine group of a molecule of an ester of an acrylic acid of the formula NO' NO' R I. ch2 = c-cooh, where R is hydrogen, methyl, ethyl or halogen, 5 is added to form a urethane or urea group, b) an additive in the form of at least one compound which corresponds to one of the general formulas below, N-RÖ-N n-R8-N in which R7 and R8 represent an organic radical, and c) a radical-forming polymerization initiator. 2. Composition according to claim 1, characterized in that R7 and R8 are a substituted or unsubstituted alkyl, cycloalkyl, aryl, aralkyl or alkaryl 3o radical, which can be branched or can have ether bonds and sulfur or nitrogen bridges, or represent a heterocyclic radical. 3. Composition according to claim 1 or 2 with a component (a) of the general formula I. 35 0 R 0 0 0 0 CH2 = C -C-0-R6-Q- (C-NH-I-NH-C-D-) nC-NH-I-NH-C- C-NH-I-Y- released 45 m-2 (I) which is a sub-formula if n = 1 and m is greater than 2, where n is 0 or 1, . m is an integer greater than 1, which is equal to the valence of D, z is an integer greater than 1, which is equal to the valence of Z, R5 is hydrogen, chlorine, methyl or ethyl, R6 is an alkylene group with 1 to 8 carbon atoms or a phenylene or naphthylene group, Q is an oxygen atom or a group as it results when one or the amine hydrogen atom is removed from a primary or secondary amino group, I an organic residue, D is an m-valent radical as it results when, in the case of an aromatic, heterocyclic or cycloaliphatic poly-ol molecule which has a number m of hydroxyl groups esterifiable with acid, the hydrogen atom is removed from each of these hydroxyl groups, or an m-valent group Residue, as it results when an aromatic, heterocyclic or cycloaliphatic polyamine molecule, which has a number m of acylatable amine groups, an amine hydrogen atom is removed from each of these amine groups, 50 Y is a urethane or urea group whose atom bonded to I is an N atom to which an H atom is bonded, and Z is a z-valent radical as it results when from a molecule of a polymeric or copolymeric polyol z 55 hydrogen atoms belonging to z with acid-esterifiable hydroxyl groups are removed, or a z-valent radical as it results when from a molecule of a polymeric or copolymeric polyamine z amine hydrogen atoms belonging to z acylatable amine groups are taken away, and / or the general formula II 65 R50 I II O II ch2 = c-c-0-r6-x-c -nh - - B, (II) in which n 'is an integer from 2 to 6, B is a polyvalent organic radical from the group of the substituted or unsubstituted 643 587 substituted alkyl, alkenyl, cycloalkyl, cycloalkenyl, aryl, aralkyl, alkaryl and heterocyclic radicals mean R2 I. tet, X represents -O- or -N-, where R2 is hydrogen or an alkyl radical having 1 to 7 carbon atoms, and R5 and R6 have the meaning given above. 4. Composition according to claim 3, characterized in that Z is derived from a polybutadiene or copolybutadiene polyol or polyamine having 5 to 150 butadiene units, of which at least 70% are in the 1,4 configuration. 5 indicates that the accelerator is an imide or amine. 20. The composition according to claim 3, characterized in that the radical-forming initiator is a UK-activatable initiator. 21. The composition according to any one of claims 1 to 20, characterized in that it additionally contains an organic Contains solvents. 22. The composition according to claim 21, characterized in that the solvent is a co-reactive solvent. 5. Composition according to claim 3, characterized in that Z is derived from a polyether or copolyether polyol with alkylene ether units, the alkylene group of which is a methylene or polymethylene group. 6. The composition according to claim 3, characterized in that Z is derived from a polyalkylene ether polyol which is grafted with olefinically unsaturated monomer, in particular from a polyalkylene ether polyol to which a vinyl polymer or copolymer is grafted. 7. The composition according to claim 3, characterized in that I is a toluene or methylene bisphenylene radical. 8. The composition according to claim 7, characterized in that D is a residue derived from bisphenol-A or hydrogenated bisphenol-A. 9. The composition according to claim 3, characterized in that R6 is an alkylene group having 2 or 3 carbon atoms. 10. The composition according to claim 3, characterized in that B is a cycloalkyl, aryl or aralkyl radical. 11. The composition according to claim 3, characterized in that the additive is a compound of the general formula n-R8-N 18. The composition according to claim 15, characterized in that it additionally contains a polymerization accelerator. 19. The composition according to claim 18, thereby 12. The composition according to claim 11, characterized in that the additive is m-phenylenedimaleinimide. 13. The composition according to claim 11, characterized in that the additive is a bis-maleimide of methylenedianiline or oxydianiline. 14. The composition according to claim 11, characterized in that the additive is an additive obtainable by reacting methylenedianiline with a molar excess of a bis-maleimide of methylenedianiline. Composition according to claim 3, characterized in that the free radical initiator is a peroxy compound, e.g. is a perester compound. 15 is. 16. The composition according to claim 15, characterized in that the initiator is a diacyl peroxide. 17. The composition according to claim 15, characterized in that the initiator is a hydroperoxide and the composition has anaerobic curing properties.