GB2123431A - Fire-retardant photopolymers - Google Patents

Abstract

Liquid polythioethers are obtained by reacting allylic or methallylic tetrahalophthalates of formula <IMAGE> (where X is halogen and R1 and R2 are hydrogen or methyl) with polythiol compounds. The liquid polymers are mixed with further polythiol compound to obtain compositions which are photopolymerizable to form hard, fire-retardant materials.

Description

SPECIFICATION Fire-retardant photopolymers Allylic esters of phthalic acids and anhydrides have been prepared by a variety of standard esterification procedures. For example, the reaction of allylic halides with metal salts of phthalic acids has been described, in both aqueous and anhydrous systems, usually in the presence of a tertiary amine catalyst. This esterification is a two-step reaction, requiring first the preparation of the metal salt of phthalic acid and second the reaction of the metal phthalate with the allylic halide.The requirement in this process for initial preparation of the phthalate salt from the phthalic acid, before the actual esterification, is accompanied by several disadvantages; in anhydrous systems the process of preparing the anhydrous metal phthalate is time-consuming since the salt must be prepared in aqueous solution and subsequently dried and requires special equipment due to corrosion problems; if the metal phthalate is prepared and used in aqueous medium, substantial decomposition of the allylic halide in the subsequent esterification may occur due to its instability in the presence of water, and there is the economic disadvantage of requiring an additional operation in the overall synthesis.

In U. S. Patent 3,086,985, to overcome the above mentioned disadvantages, a new method of preparing allylic halides is taught which provides for the direct reaction, in one step, of a phthalate acid or anhydride with an allylic halide using an amine catalyst.

U. S. Patent 3,035,084 teaches synthesis of methallyl phthalates from salts of phthalic acid using as well an amine catalyst.

French Patent 1,372,967 introduces a novel catalyst, namely a copper halide, metallic copper mixture to effect the synthesis of allyl phthalate by the same reaction route of the above discussed patents, namely conversion of the phthalic acid or anhydride to its salt via alkaline neutralization and subsequent reaction with an allyl halide.

Allyl esters of phthalic acids have found a variety of uses as plasticizers, as chemical intermediates and as taught, for example, in U. S. Patents 3,824,104, 3,376,139 and 3,891,695 as components of photosensitive compositions.

Furthermore, the halogenated allylic esters of phthalic acids have found a variety of applications such as in insecticide compositions, as light-stabilizers for polyvinyl halide resins, and, additionally, these compounds are useful in the preparation of polymers which, due to the high halogen content, are flameretardant in nature. As an example of art documenting particularly the last application, one may refer to U. S. Patent 4,105,710 which teaches the imparting of flame-retardant properties to curable vinyl unsaturated polymers by incorporation therein of diallyl tetrabromophthalate. These halogenated allyl esters of phthalic acid may be made by a variety of methods, e. g., by the reaction of a halogenated phthalic anhydride and an alcohol as described in U. S.Patent 2,462,601 by the reaction of the alkali metal salt of a tetrahalophthalic acid and an alkyl alcohol as illustrated in U.S. Patent 2,617,820, etc.

In response to the need for developing compositions suited for the application as coatings for electronic circuitry, which incorporate two basic properties, namely (a) that they be radiation curable and (b) that they be fire-retardant, research programs have been devised which, inter alia, have focussed on the aforediscussed halogenated allyl phthalic esters since these compounds meet these two basic requirements.

These and other requirements have been met by the novel flame-retardant photosensitive compositions of the present invention which combine excellent UV curability and very good flame-retardant properties. These compositions are suitable inter alia for coatings for electronic circuitry.

The compositions of the present invention comprise (1) a liquid, chain-extended, thioether-containing allylic or methallylic tetrahalophthalate or a mixture thereof, and (2) a polythiol.

The liquid, chain-extended thioether-containing allylic or methallylic tetrahalophthalates are made by reacting a solid tetrahalophthalate with a polythiol.

Optionally in combination with photoinitiators and other additives, they result in screenable liquids which can be applied to electronic circuit boards and cured with UV light to hard fire-retardant coatings.

According to a feature of the present invention tetrahalophthalic anhydrides are converted to salts in base and reacted with allyl chloride and/or methallyl chloride in the presence of copper/cuprous chloride catalyst to give allyl / methallyl tetrahalophthalate esters in high yield and purity.

The halogenated allyl and methallyl esters covered by the present disclosure have the following structure:

where (1)X=Br and R1=R2=H; (2)X=Br and R, = R2 = CH3; (3) X = Br and R1 = H and R2 = CH3; (4) X = Cl and R, = R2 = H; (5) X = CI and R, = R2 = CH3 or (6) X = CI, R, = H and R2 = CH3. While compound 1 is a known compound (taught in U. S. Patent 4,105,710), compounds 2 through 6 are not documented in the prior art. U. S.Patent 3,035,084, while teaching preparation of the methallylic phthalate, as in the case of compound 5, does not teach the preparation of a haiogenated methallylic phthalate, and, furthermore, synthesis of any of these halogenated compounds 1 through 6 by use of copper/cuprous chloride catalyst and by the reaction method described is also not disclosed in the prior art even though use of the catalyst and the reaction method are known for synthesis of non-halogenated phthalates as evidenced by the patents referred to above.

These polyenes, which are crystalline solids, are prereacted with a sub-stoichiometric amount of polythiol in the presence of a free radical thermal initiator, e. g., benzopinacol to give a liquid mixture. This mixture is then formulated with additional polythiol and optionally a photoinitiator and other additives to make screenable liquids which can be applied to electronic circuit boards and cured with UV light to hard fire-retardant coatings.

The use of benzopinacol to prereact a polyene with a substoichiometric amount of a polythiol is disclosed in U. S. Patent 4,020,233.

Polythiols operable herein are simple or complex organic compounds having a multiplicity of pendant or terminally positioned -SH functional groups per average molecule.

The polythiol must contain 2 or more -SH groups/molecule and have a viscosity range of essentially 0 to 20 million centipoises (cps) at 70"C as measured by a Brookfied Viscometer either alone or when in the presence of an inert solvent, aqueous dispersion or plasticizer. Operable polythiols in the instant invention usually have molecular weights in the range of about 94 to about 20,000 and, preferably, from about 100 to about 10,000.

The polythiols operable in the instant invention may be exemplified by the general for mula R8-(SH)n where n is at least 2 and R8 is a polyvalent organic moiety free from reactive carbon-to-carbon unsaturation. Thus, R8 may contain cyclic groupings and hetero atoms such as N, P or 0 and primarily contains carbon-carbon, carbon-hydrogen, carbon-oxygen or silicon-oxygen containing chain linkages free of any reactive carbon-to-carbon unsaturation.

One class of polythiols operable herein are esters of thiol-containing acids of the formula HS-R9-COOH where R9 is an organic moiety containing no reactive carbon-to-carbon unsaturation with polyhydroxy compounds of structure R,,-(OH), where R,o is an organic moiety containing no reactive carbon-to-carbon unsaturation, and n is 2 or greater. These compo nents will react under suitable conditions to give a polythiol having the general structure:

where B9 and Ro are organic moieties containing no reactive carbon-to-carbon unsaturation, and n is 2 or greater.

Polythiols such as the aliphatic monomeric polythiols (ethane dithiol, hexamethylene dithiol, decamethylene dithiol, tolylene-2,4-dithiol and the like) are operable herein.

Examples of the polythiol compounds preferred include, but are not limited to, esters of thioglycilic acid (HS-CH2COOH), alpha-mercaptopropionic acid (HS-CH(CH3)-COOH and beta-mercaptopropionic acid (HS-CH2 CH2COOH) with polyhydroxy compounds such as glycols, triols, tetraols, pentaols, hexaols and the like. Specific examples of the preferred polythiols include, but are not limited to, ethylene glycol bis(thioglycolate), ethylene glycol bis (beta-mercapto-propionate), trimethylolpropane tris (thioglycolate), trimethylolpropane tris-(beta-mercaptopropionate), pentaerythritol tetrakis (thioglycolate) and pentaerythritol tetrakis (beta-mercaptopropionate), all of which are commercially available.A specific example of a preferred polymeric polythiol is polypropylene ether glycol bis(beta-mercaptopropionate) which is prepared from polypropylene-ether glycol (e. g., Pluracol P2010, Wyandotte Chemical Corp.) and beta-mercaptopropionic acid by esterification.

Polythiol terminated poloxyalkylene polyols, such as trimethylolpropane tris-(3-mercapto-2hydroxypropyl-monooxypropyl) ether and tri methylolpropane tris-(3-mercapto-2-hydroxypropyl-dioxypropyl) ether, are also operable.

Furthermore, saturated alicyclic dithiols, such as 1, 5-cyclooctanedithiol, 3,7,11 -trimethyl 1 ,5-cyclododecanedithiol, 4-hexyl-1 ,2,-cyclo- hexanedithiol, ethylcyclohexyl dithiol and dlimonene dithiol represent commercially available dithiols that are operable herein.

Additionally, polythiols operable herein to give cured solid polythioether products with the polyene in the presence of a photoinitiator include the mercaptoester derivatives of styrene-allyl alcohol copolymers set out in U. S.

Patent 3,904,499 and the isocyanurate containing polythiols disclosed in U. S. Patent 3,676,440 and liquid thiol-terminated poly mers made in accord with U. S. Patent 3,258,495, all incorporated hereby by reference. An example of the aforesaid latter type liquid thiol-terminated polymer is CAPCURE 3-800, commercially available from Diamond Shamrock Chemical Company.

In carrying out the reaction to transform the crystalline solid polyenes to a chain-extended, polythioether containing liquid by reaction with a polythiol in the presence of a free radical thermal initiator, the amount of polyth iol used is a substoichiometric amount. Suffi cient polythiol must be used to convert the solid crystalline polyene to liquid polythioether but care- must be exercised that not too much polythiol is added which could increase viscosity too much or cause gelling. It has been found that a range of 0.1 to 0.25 equivalents SH/equivalent of double bond in the polyene is operable to satisfy the aforesaid requirements.Following the chain extending reaction, additional polythiol is added to the system to supply the stoichiometric amount necessary to react with the remaining carbonto-carbon double bonds in the chain-extended polyene optionally along with a photoinitiator for use as a photocurable composition.

The chain-extending reaction is performed at temperatures above the melting point of the polyene and the disassociation temperature of the free radical thermal initiator. Temperatures in the range 60 to 150"C are usually employed.

The free radical, thermal initiators used herein are selected from substituted or unsubstituted pinacols, azo compounds, thiurams, organic peroxides and mixtures thereof.

The organic peroxides operable are of the general formula: R-O-O-(R,-O-O),-R wherein n = O or 1, R is independently selected from hydrogen, aryl, alkyl, aryl carbonyl, alkaryl carbonyl, aralkyl carbonyl and alkyl carbonyl and R, is alkyl or aryl, said alkyl groups containing 1 to 20 carbon atoms.

Examples of operable organic peroxides include, but are not limited to, 2,5-dimethyl 2,5-di(t-butylperoxy)-hexane, 1,3-bis(t-butylperoxyisopropyl)benzene, 1,3-bis-(cumylperoxyisopropyl)benzene, 2,4-dichlorobenzoyl peroxide, caprylyl peroxide, lauroyl peroxide, t-butyl peroxyisobutyrate, benzoyl peroxide, pchlorobenzoyl peroxide, hydroxyheptyl peroxide, di-t-butyl diperphthalate, t-butyl pleracetate, t-butyl perbenzoate, dicumyl peroxide, 1 , 1 -di(t-butylperoxy)-3, 3, 5-trimethyl-cyclohex- ane and di-t-butyl peroxide.

Examples of azo compounds operable herein include, but are not limited to, commercially available compounds such as 2-tbutylazo-2-cyanopropane; 2, 2'-azobis(2,4-d methyl-4-methoxy-valeronitrile); 2,2'azobis(isobutyronitrile); 2,2'-azobis(2,4-dimethylvaleronitrile) and 1,1 '-azobis-(cyclohexanecarbonitrile).

The thiurams operable as thermal initiators herein are of the formula:

wherein R,, R3, R3 and R4 taken singly can be hydrogen, linear or branched alkyl having from 1 to about 1 2 carbon atoms, linear or branched alkenyl having from 2 to about 1 2 carbon atoms, cycloalkyl having from 3 to about 10 ring carbon atoms, cycloalkenyl having from 3 to about 10 ring carbon atoms, aryl having from 6 to about 1 2 ring carbon atoms, alkaryl having from 6 to about 1 2 ring carbon atoms, aralkyl having from 6 to about 1 2 ring carbon atoms and, when taken together, R, and R2 and R3 and R4 can each be a divalent alkylene group (-CnH2n-) having from 2 to about 1 2 carbon atoms, a divalent alkenylene group (-CnH2m2-) group having from 3 to about 10 carbon atoms, a divalent alkadienylene group -(CnH2n-4)- having from 5 to about 10 carbon atoms, a divalent alkatrienylene group -(CnH2n 6)- having from 6 to about 10 carbon atoms, a divalent alkyleneoxyalkylene group (-CXH2xOLCxH2x-) having a total of from 4 to about 1 2 carbon atoms or a divalent alkyleneaminoalkylene group:

having a total of from 4 to about 1 2 carbon atoms.

Operable thiurams include, but are not limited to, tetramethylthiuram disulfide, tetraethylthiuram disulfide, di-N-pentamethylenethiuram disulfide, tetrabutylthiuram disulfide, dipehnyldimethylthiuram disulfide, diphenyl-diethylthiuram disulfide and diethyleneoxythiuram disulfide and the like.

The substituted or unsubstituted pinacols operable herein as a thermal initiator have the general formula:

wherein R, and R3 are the same or different substituted or unsubstituted aromatic radicals, R2 and R4 are substituted or unsubstituted aliphatic or aromatic radicals and X and Y which may be the same or different are hydroxyl, alkoxy or aryloxy.

Preferred pinacols are those wherein R,, R2, R2 and R4 are aromatic radicals, especially phenyl radical and X and Y are hydroxyl.

Examples of this class of compounds include, but are not limited to, benzopinacol, 4,4'-dichlorobenzopinacol 4,4'-dibromobenzopinacol, 4,4'diiodobenzopinacol, 4,4',4",4"'tetrachlorobenzopinacol, 2,4,2', 4'-tetrachloro- benzopinacol, 4,4'-dimethylbenzopinacol, 3,3'-dimethyl-benzopinacol, 2,2'-dimethylben- zopinacol, 3,4,3',4'-tetra-methylbenzopinacol, 4,4'-dimethoxybenzopinacol, 4,4',4",4"'-tetramethoxybenzopinacol, 4,4'-diphenylbenzopi nacol, 4,4'-dichloro-4",4"'-dimethylbenzopi- nacol, 4,4'-dimethyl-4",4"'-diphenylbenzopinacol, xanthonpinacol, fluoroenonepinacol, acetophenonepinacol, 4,4'-dimethylaceto-phenone-pinacol, 4,4'-dichloroacetophenonepinacol, 1,1 ,2-triphenyl-propane-1 ,2-diol, 1,2,3,4 tetraphenyl-butane-2,3-diol, 1,2-diphenylcy clobutane-1 ,2-diol, propiophenone-pinacol, 4,4'-dimethylpropiophenone-pinacol, 2,2' ethyl-3, 3'-dimethoxypropiophenone-pinacol, 1,1 , 1 ,4,4,4-hexafluoro-2,3-diphenyl-butane- 2, 3-diol.

As further compounds according to the present invention, there may be mentioned: benzopinacol-mono-methylether, benzopinacolmono-phenylether, benzopinacol and monoisopropyl ether, benzopinacol monoisobutyl ether, benzopinacol mono (diethoxy methyl) ether and the like.

The aforementioned free radical, thermal initiators are added to the composition in amounts ranging from 0.01-1.0% by weight based on the weight of the polyene and polythiol.

The compositions of the present invention may, if desired, include such additives as antioxidants, accelerators, dyes, inhibitors, activators, fillers, pigments, antistatic agents, flame-retardant agents, thickeners, thixotropic agents, surface-active agents, viscosity modifiers, extending oils, plasticizers, tackifiers and the like within the scope of this invention.

Such additives are usually preblended with the ethylenically unsaturated compound or polythiol prior to or during the compounding step. Operable fillers include natural and synthetic resins, carbon black, glass fibers, wood flour, clay, silica, alumina, carbonates, oxides, hydroxides, silicates, glass flakes, glass beads, borates, phosphates, diatomaceous earth, talc, kaolin, barium sulfate, calcium sulfate, calcium carbonate, antimony oxide and the like.

The aforesaid additives may be present in quantities up to 500 parts or more per 100 parts of ethylenically unsaturated compound and polythiol by weight and preferably about 0.005 to about 300 parts on the same basis.

The curing reaction to form hard, fire-retardant coatings on substrates is preferably, but not necessarily, carried out in the presence of a photoinitiator. Various photoinitiators operable herein include, but are not limited to, benzophenone, acetophenone, o-methoxybenzophenone, acenapthene-quinone, methyl ethyl ketone, valerophenone, hexanophenone, alpha-phenylbutyrophenone, p-morpholinopropiophenone, dibenzosuberone, 4-morpholinobenzophenone, 4'-morpholinodeoxybenzoin, p-diacetyl-benzene, 4-aminobenzophenone, 4'methoxyacetophenone, benzaldehyde, alphatetralone, 9-acetylphenanthrene, 2acetylphenanthrene, 1 0-thioxanthenone, 3acetyl-phenanthrene, 3-acetylindole, 9-fluorenone, 1 -indanone, 1,3, 5-triacetylbenzene, thioxanthen-9-one, xanthrene-9-one, 7-H-benz ide]anthracen-7-one, 1-naphthaldehyde, 4,4'bis(dimethylamino) benzophenone, fluorene-9one, 1'-acetonaphthone, 2'-acetonaphthone, 2,3-butanedione, triphenylphosphine, tri-o-tolyphosphine, acetonaphthone, 2,3-butanedione, benz[a anthracene-7.1 2-dione, etc.

Another class of photosensitizers is the benzoin ethers, such as benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether and benzoin isobutyl ether. The photosensitizers are usually added in an amount ranging from 0.0005 to 30% by weight of the ethylenically unsaturated compound and the polythiol.

In addition, the halogenated allyl compound in the composition of this invention can act as its own photoinitiator, without added photoinitiator of the above types.

When UV radiation is used, an intensity of 0.0004 to 60.0 watts/cm2 in the 250-400 nanometer region is usually employed.

The curing reaction can also be accomplished by using high energy ionizing radiation at a dose rate in the range 0.00001 to 1,000 megarads/second.

The amount of ionizing radiation which is employed in curing in the instant invention can vary between broad limits. Radiation dosages of less than a megarad up to 10 megarads or more for electrons are operable; preferably 0.02 to 5 megarads energy absorbed are employed.

The following examples will aid to explain, but specifically not limit, the subject invention unless, otherwise noted, all parts and percentages are by weight.

Example 1 Synthesis of Diallyl Tetrabromophthalate (DATBP) A mixture of 464 9 tetrabromophthalic anhydride, 80 9 sodium hydroxide, 650 ml water, 0.04 g copper powder, 2 g cuprous chloride and 306 g allyl chloride was stirred 2 hours at 70"C to give 528 9 (94%) diallyl tetrabromophthalate. The pH was kept between 6.5 and 7.5 by adding sodium hydroxide solution during the reaction.

Example 2 Dimethallyl tetrabromophthalate (DMATBP) was synthesized in a similar manner as set out in Example 1 by using methallyl chloride in place of allyl chloride.

Example 3 A mixture of allyl methallyl tetrabromophthalate, DATBP and DMATBP was synthesized in a similar manner as set out in Example 1 by using a mixture of methallyl chloride and allyl chloride.

Example 4 Diallyl tetrachlorophthalate was synthesized by the same procedure in Example 1 using tetrachlorophthalic anhydride in place of tetrabromophthalic anhydride.

Example 5 A mixture of 5.0 g diallyl tetrabromophthalate, 5.25 g of dimethallyl tetrabromophthalate, 10.0 g diallyl tetrachlorophthalate, 2.4 g ethylene glycol bis-(3-mercaptopropionate) and 0.16 g benzopinacol was heated for 30 minutes at 110"C to form a chain-extended, liquid polymer. Thereafter, at 60"C, 9.1 g ethylene glycol bis-(3-mercaptopropionate) and 9.52 g of finely divided hydrated alumina (HYDRAL 710 from Alcoa) was added and mixed.

This formulation was shown to screen-print well, to photocure fast and to exhibit good solder resistance and, most importantly, testing of 2 ten-mil thick films have revealed it to be flame-retardant as reflected by an average Oxygen Index of 29.

In general, flame retardancy is measured by ASTM Method D 2863-74 for oxygen index; an oxygen index of about 27-28 or higher is considered generally acceptable.

While suitable for application to electronic circuit boards, other applications for this composition may be easily envisaged where radiation curable fire-retardant coatings are required.

Variations may be made in materials, proportions and procedures without departing from the scope of this invention.

Example 6 2.09 g of diallyl tetrabromophthalate from Example 1 and 0.91 g of pentaerythritol tetrakis(beta-mercapto-propionate) were mixed in a 1 3 mm test tube and slowly melted at 80-85"C to a clear solution. The solution was transferred to a glass plate and spread as a 20 mil thick film thereon. The film was exposed to UV radiation from a Ferro UV lamp for 1 minute. A solid, cured film resulted.

Example 7 Example 6 was repeated except that a photoinitiator, i. e., 0.03 g of 2,2-dimethoxy-2phenylacetophenone, was added to the system. Asolid, cured film resulted.

Example 8 Example 6 was repeated except that a photoinitiator, i. e., 0.03 g of dibenzosuberone, was added to the system. A solid, cured film resulted.

Example 9 Example 6 was repeated except that a photoinitiator, i. e., 0.03 g of 4,4'-dimethoxybenzophenone, was added to the system. A solid, cured film resulted.

Example 10 Example 6 was repeated except that a photoinitiator, i. e., 0.03 g of benzophenone, was added to the system. A solid, cured film resulted.

Example 11 Example 6 was repeated except that 0.01 g of benzopinacol was added to the original mixture and, after formation of the thioethercontaining chain-extended polyene, 0.03 9 of 2,2-dimethoxy-2-phenylacetophenone was added prior to irradiation. A solid, cured film resulted.

Example 12 A mixture of 20.48 g of diallyl tetrachlorophthalate, 2.06 g pentaerythritol tetrakis(betamercaptopropionate) and 0.01 g benzopinacol were heated with stirring at 125"C for 1 hour to form a chain-extended, liquid polymer. The polymer was cooled to 60"C and 0.26 g of 2, 2-dimethoxy-2-phenylacetophenone, 0.03 g of pyrogallol and 0.005 g of phosphorous acid were added to the system along with 1 0.28 g of pentaerythritol tetrakis(beta-mercapto-propionate). This admixture was spread as a 20 mil thick coat on a glass plate and exposed to UV radiation for 2 1/2 minutes. A solid, cured, transparent coating adhering to the glass plate resulted.

Claims (12)

1. A flame-retardant, photocurable composition comprising: (1) a liquid, chain-extended, thioether-containing allylic or methallylic tetrahalophthalate or a mixture thereof, and (2) a polythiol.

2. A composition according to Claim 1 also containing a photoinitiator.

3. A composition according to Claim 1 or 2 wherein the tetrahalophthalate has the structure:

where (1) X= Br and R1 = R2 = H; (2) X= Br and R1 = R2 = CH3; (3) X = Br, R, = H and R2 = CH2; (4) X = Cl and R, = R2 = H; (5) X = Cl and R, = R2 = CH2; or (6) X = Cl, R, = H and R2 = CH2.

4. A composition according to Claim 1 substantially as hereinbefore described.

5. The process of forming a liquid, chainextended thioether-containing allylic or methallylic tetrahalo-phthalate which comprises reacting a solid tetrahalophthalate of the formula:

where (1) X = Br and R, = R2 = H; (2) X = Br and R, = R2 = CH2; (3) X = Br, R, = H and B2=CH2; (4)X=Cl and R, =B2=H; (5) X = CI and B1 = B2 = CH3; or (6) X = Cl, R, = H and R2 = CH2, with a polythiol in an amount so as to provide 0.1 to 0.25 equivalents SH/equivalent of carbon-to-carbon double bond in the tetrahalopthalate at a temperature in the range 60 to 150 C.

6. A process according to Claim 5 wherein the reaction is effected in the presence of a free radical thermal initiator.

7. A process according to Claim 6 wherein the free radical thermal initiator is benzopinacol.

8. A process for forming a coating on a substrate which comprises applying to a substrate a flame-retardant, photocurable composition as claimed in any of Claims 1 to 4 and, thereafter, subjecting the said coated substrate to UV radiation.

9. A process according to claim 5 substantially as hereinbefore described.

10. A liquid, chain-extended thioethercontaining allylic or methallylic tetrahalophthalate produced by the process of Claim 5, 6 or 9.

11. A process according to Claim 8 substantially as hereinbefore described.

12. A coated substrate formed by the process of Claim 8 or 11.