3,010,941 United States Patent Office Patented Nov. 28, 1961 2 3,010,941 Unsaturated acetals which correspond to the formula FLAME-RESISTANT SPIROBI(META-DOXANE) include: PHENOLC COMPOSITIONS O CE CHO Howard R. Guest, Charleston, and Ben W. Kiff, Ona, W. Va., assignors to Union Carbide Corporation, a cor CH=CH-cá Y/ ic-CH=CH, poration of New York Yo off, YoHo, No Drawing. Filed Aug. 29, 1958, Ser. No. 757,899 3,9-divinylspirobi (meta-dioxane) 14 Claims. (Cl. 260-47) Cl OCH CHO Cl This invention relates to a new class of resins derived O from 3,9-dialkenylspirobi (meta-dioxane) derivatives. In CH-5-off Ye?/ ic-C-CH, a particular aspect, this invention relates to resins con Yo cé, YoH,0^ taining spirobi (meta dioxane) and phenolic groups, and 3,9-di(1-chlorovinyl)spirobi(meta-dioxane) chemically-bound phosphorus. Resins formed by the polymerization of spirobi (meta CF3 OCH CHO CE dioxane) derivatives with phenols have many properties CH-5–c?, Ye/ ic-C-CH, which make them commercially attractive. They are hard Yo cá, YoHo, and tough and can be made with good clarity and color. 3,9-diisopropenylspirobi(meta-dioxane) However, in common with most other organic plastic ma O CH, CHO terials commercially available, they suffer the disadvantage 20 of being flammable. In many applications, particularly CH-CH=CH-off Y/ He-CH=CH-CH, in the structural field, there would be great advantage in having a strong, tough, rigid plastic with excellent weather 3,9-dipropenylspirobi(meta-dioxane) ability characteristics which at the same time was flame resistant. 25 Unsaturated spirobi (meta-dioxane) derivatives are read A conventional method of reducing the flammability of ily prepared by the condensation of a mole of pentaeryth a plastic is to incorporate mechanically a phosphorus ritol with two moles of an unsaturated aldehyde or ketone, containing plasticizer into the plastic by milling or other or mixtures thereof, in the presence of an acid catalyst similar operation. Considerable quantities of such plasti such as p-toluenesulfonic acid. The following reaction cizers are required to produce this flame-resistance prop 30 schemes are illustrative of the general synthetic method. erty in the plastic. Usually the plasticizer modifies other When acrolein is employed, an unsubstituted 3,9-divinyl properties of the plastic in a beneficial way at the same spirobi (meta-dioxane) is obtained: time. Plasticizers of this type include compounds such HOCEI CH2OH. as tricresyl phosphate and trioctyl phosphate. 2CH=CHCHO- Y/ --> This method of reducing the flammability of plastics with phosphorus-containing plasticizers is not practical for HO off, YoHo H polymers produced from spirobi (meta-dioxane) deriva O CH, CHO tives and phenols. These polymers are not compatible CH-CHcá Y/ AccH-CH, with many of the phosphorus-containing plasticizers, and Yo off, YoHo, when proper compatibility between the polymers and 40 plasticizers is accomplished it is found that many of the When the condensation is conducted with an unsaturated desirable properties of the polymers are adversely ef ketone, then the three- and nine-positions of the spirobi fected. Further, no additive is known which can be (meta-dioxane) nucleus obtained have two substituents mixed mechanically with spirobi (meta-dioxane) phenolic rather than one: polymers to produce non-flammable compositions. HOCE CHOH It is a main object of this invention to provide flame CH3CH=CHCHCO CH3- Y/ H+, resistant spirobi(meta-dioxane) phenolic polymers. HO off, YoHOH Other objects and advantages of this invention will become apparent to those skilled in the art from the accompany O CB CHO ing description and disclosure. 50 CHCH=CHCH,06H, Y/ cific CHCH=CHCH3 Accordingly, flame-resistant polymers are produced by Yo c?, YoHo, reacting together a mixture of 3,9-dialkenylspirobi(meta It is not necessary that the unsaturated aldehyde or dioxane), a phenol, and a partial phosphite ester deriva ketone reacted with pentaerythritol be pure or a single tive of pentaerythritol. The polymers so produced con species. Mixtures of unsaturated aldehydres and/or ke tain chemically-bound phosphorus as a substantive part 55 tones may be condensed with pentaerythritol. The re of the polymers. sulting products are mixtures of 3,9-olefinically-substituted The 3,9-dialkenylspirobi (meta-dioxane) derivatives con spirobi (meta-dioxane) compounds which may be resolved templated are those having alkenyl substituents in the into pure components or which may be used as a crude three-position and in the nine-position, each alkenyl sub mixture directly in polymerization reactions. stituent containing between two and about eighteen car 60 The partial phosphite ester derivatives of pentaerythritol bon atoms. The respective alkenyl groups can be iden contemplated for chemically incorporating phosphorus tical or different species. A particularly useful group of into the polymers to make them flame-resistant can be pre these unsaturated acetal compounds are those derived pared by a transesterification reaction between pentaeryth from the reaction of acrolein and substituted acroleins ritol and a molar equivalent or less of a trialkyl phos with pentaerythritol. Such unsaturated acetals may be 65 phite. A major portion of the transesterification reaction represented by the formula: appears to proceed in the following manner: is oc CHso Hoc CHOH BO CH CH.0, Ric–c. 2\, so-c-CHR, (RO)3P-- 2\, a-d 2& POR-2ROH OCH CEO HOCE CHOH BOCEH, CHO wherein R1 is hydrogen, methyl or chlorine, and R2 is The transesterification reaction is preferably conducted hydrogen or methyl. between pentaerythritol and a phosphite ester which is the 3,010,941 3. 4 derivative of an alcohol that can be removed continuously As mentioned previously, the pentaerythritol partial phos from the transesterification reaction medium as the reac phite ester has free hydroxyl groups which react with tion proceeds. The ester is in equilibrium with both olefinic groups during the polymerization reaction. pentaerythritol and the exchanged alcohol so that the The quantity of partial phosphite ester employed is removal of the exchanged alcohol moiety is necessary to not narrowly critical. The preferred weight range of produce a favorable shift of the reaction equilibrium in partial phosphite ester incorporated into the resin is be the direction of pentaerythritol partial phosphite ester tween about 5 percent and 25 percent of the weight of formation. For example, triethyl phosphite and triso reactants, i.e., the total weight of 3,9-dialkenyispirobi propyl phosphite are especially suitable for this transesteri (meta-dioxane), phenolic derivative and partial phos fication method of producing pentaerythritol partial phos 10 phite ester reactants. Quantities less than about 5 per phite esters because both ethanol and isopropanol can be cent by weight may be incorporated into the composi continuously distilled off under atmospheric pressure with tions but it has been found in many cases that the resins out any difficulty and a high yield of desired product is containing these lesser quantities of pentaerythritol par obtained. The pentaerythritol partial phosphite esters, or tial phosphite ester support combustion and are not self mixtures thereof, preferred, are those which have an 5 extinguishing. Similarly, quantities of pentaerythritol average of at least two free hydroxy groups per ester mole partial phosphite ester in excess of about 25 percent by cule available for reaction with 3,9-dialkenylspirobi (meta weight of the total weight of reactants polymerized can dioxane) derivatives to produce flame-resistant resins. be employed if desired. However, such larger quantities The phenol derivatives which can be employed in the of pentaerythritol partial phosphite ester do not appre practice of this invention are the compounds of this class 20 ciably increase the flame-resistance of the resins and they which contain at least two positions ortho or para to a may deleteriously affect other characteristics of the resins. phenolic hydroxyl group on an aromatic hydrocarbon It is desirable to conduct the polymerization reaction nucleus which are susceptible to substitution reactions, in the presence of an acidic curing catalyst to promote a e.g., compounds having positions ortho and para to a reasonable reaction rate. Satisfactory curing catalysts phenolic hydroxyl group which contain an active hydro include acidic catalysts such as sulfuric acid, hydro gen substituent that can be displaced by an electrophilic chloric acid, toluenesulfonic acid, benzenesulfonic acid, reagent. The phenols contemplated include mononuclear boron trifluoride, aluminum chloride, dialkyl sulfates phenols such as phenol, chlorophenol, resorcinol, p-phen such as diethyl sulfate, dimethyl sulfate, diisopropyl sul ylphenol, phloroglucinol, hydroquinone, cresol, m-xylenol, fate and the like, titanium tetrachloride, phenyl acid beta-naphthol, mixtures of phenols from coal tar or 30 phosphate, octylphenyl acid phosphate, and the like. coal hydrogenation fractions, and the like; dinuclear Curing catalyst concentrations can vary from as little as phenols such as 2,2-bis(p-hydroxyphenyl)propane, bis 0.1 percent by weight for the more active catalysts, up (p-hydroxyphenol) methane and isomeric diphenylol to 1.0 weight percent or higher for the less active cata methanes disclosed in Bender et al., United States Patent lysts, based on the total weight of the reaction mixture. No. 2,744,882, and the diphenols disclosed in Bender et 35 In another method found convenient for preparing al., United States Patent No. 2,506,486, and the like; tri flame-resistant polymers, 3,9-dialkenylspirobi (meta-diox nuclear phenols such as 1,1,3-tris(hydroxyphenyl) pro ane) and a phenol are reacted together in suitable pro pane, 1,1,3-tris(hydroxytolyl)-propane, 1,1,3-tris(hydroxy portions to produce a liquid pre-condensate A-stage resin phenyl)propene-2, 1,1,3-tris(hydroxyphenyl)-2-methyl in the presence of an acid catalyst. The pre-condensate propane, and the like; and other higher polynuclear 40 polymerization reaction is conducted at a temperature phenols. The terms "mononuclear phenol,” “dinuclear - between about 100° C. and 150° C. for a period of time phenol" etc., designate the number of aromatic hydrocar between one-half hour and five hours depending on the bon nuclei in a compound containing at least one phenolic viscosity desired for the A-stage resin. After volatile hydroxyl group. For example, by "mononuclear phenol." materials have been removed by distillation, the A-stage is meant a compound having one aromatic hydrocarbon resin is usually a viscous liquid which slowly condenses nucleus which contains one or more phenolic hydroxy to a solid plastic on standing. For practical purposes, groups, such as cresol or resorcinol. The expression "a the condensation can be stopped by neutralization or re phenol' as used hereinafter is meant to include all phenol moval of the catalyst. The neutral A-stage resin can be derivatives within the scope of the foregoing definition. stored until needed. The reaction for producing flame-resistant spirobi (meta 50 Flame-resistant polymers are prepared from the A-stage dioxane) polymers can be conducted by the simple ex resin by mixing a calculated quantity of partial phosphite pediency of heating a mixture of 3,9-dialkenylspirobi ester of pentaerythritol into the said resin and heating (meta-dioxane), a phenol, and partial phosphite ester of the mixture until complete curing is obtained. A curing pentaerythritol at a temperature between about 100° C. catalyst is also added to the mixture, unless the catalyst and 150° C. The polymerization may require a reaction 5 5 employed for preparing the pre-condensate A-stage resin period of twenty-four hours or longer at the lower reac is still present in the mixture in a sufficient quantity to tion temperatures, and a reaction period as short as five promote formation of a cured, flame-resistant resinous minutes may be satisfactory to complete the curing of product. This final cure can be accomplished at the the polymer product at the higher temperatures. same temperature used for the formation of the interme The relative concentrations of the reactants can be 60 diate A-stage resin, or at higher temperatures. varied over a wide range in producing the flame-resistant The flame-resistant spirobi (meta-dioxane) phenolic resins. For example, phenol has three reactive ortho and para positions (trifunctional) and 3,9-dialkenylspirobi polymers of this invention can be employed to produce (meta-dioxane) has two double bonds (difunctional) so molded articles, laminates, or any product for which that the theoretical combining ratio is one and one-half other thermosetting resins are used. The polymers of moles of 3,9-dialkenylspirobi (meta-dioxane) for every this invention have the advantage of being self-extinguish mole of phenol. Resins with desirable properties can be ing when ignited, besides being strong, tough and rigid. produced over the range of between one mole and three These flame-resistant polymers also have the advan moles of 3,9-dialkenylspirobi (meta-dioxane) for every tage over many other thermoset resins in that they cured mole of phenol. Generally, it is practical to use not less 70 without the formation of volatile by-products, such as than one and one-half moles of 3,9-dialkenylspirobic meta water, and there is little or no shrinkage during the cur dioxane) for each mole of phenol reacted. Preferably, ing process. a quantity of 3,9-dialkenylspirobi(meta-dioxane) is em The following examples will serve to illustrate specific ployed which is equivalent to the functionality of both embodiments of this invention. The first three examples the phenol and the pentaerythritol partial phosphite ester. . 75 demonstrate the flammability of spirobi (meta-dioxane) 3,010,941 5 6 phenolic resins which do not contain polymer-bound Example 5 phosphorus. A liquid pre-condensate was prepared by reacting 3,9- Example 1 divinylspirobi (meta-dioxane) (945 grams) with phenol A charge of 3,9-divinylspirobi (meta-dioxane) (405 (280 grams) in the presence of diethyl sulphate catalyst grams), phenol (120 grams), and diethyl sulfate (1.68 (3.68 grams). A portion of this liquid pre-condensate grams) was placed in a reaction flask and heated for a (133 grams) was mixed with 7 grams of partial phosphite period of fifty minutes at a temperature of 100 C. to ester prepared according to the method described in Ex 120° C. At the conclusion of the reaction period, the ample 4. The partial phosphite ester was 5.0 percent by liquid resin was poured into molds and cured for a period weight of the total charge. After the mixture was heated of sixteen hours at a temperature of 150 C. The result O for a period of forty minutes at a temperature of 110° C. ing cured polymer was a dark, hard material with the to 115° C., it was poured into molds and cured for sixteen following properties: hours at a temperature of 150° C. The resulting polymer Heat distortion------C. 149 was hard, tough, clear and smooth, and was self-extin Hardness, durometer 'D'------81 guishing within eight seconds when a thin bar Impact strength (Izod), ft. lbs./in. of notch------0.75 (5' x 4' x 4') was tested for flammability according A thin bar (5' x 4' x /s') of this material was tested to ASTM-D635-44. for fiammability according to ASTM-D635-44. The bar Example 6 burned for twenty-three minutes after it was ignited. A liquid pre-condensate was prepared by reacting 3,9- Example 2 20 divinylspirobi (meta-dioxane) (945 grams) with phenol (280 A mixture of 3,9-divinylspirobi (meta-dioxane) (318 grams) in the presence of diethyl-sulphate catalyst (3.68 grams) and 1,1,3-tris (hydroxyphenyl)propane (160 grams). A portion of this liquid pre-condensate (133 grams) was heated to a temperature of 100 C. until it grams) was mixed with 7 grams of partial phosphite ester became homogeneous. The mixture was then cooled to prepared according to the method described in Example 4. 53 C. and mixed alkanesulfonic acid (0.72 gram) was 25 The partial phosphite ester was 5.0 percent by weight of added. The liquid pre-condensate was poured into molds the total charge. After the mixture was heated for a and cured for a period of six hours at a temperature of period of forty minutes at a temperature of 110° C. to 150° C. The resulting polymer was hard, smooth and 115° C., it was poured into molds and cured for sixteen glossy, and had the following properties: hours at a temperature of 150° C. The resulting polymer 30 was hard, tough, clear and smooth, and was self-extin Heat distortion------C. 192 guishing within eight seconds when a thin bar (5' x 72’ Impact strength (Izod), ft. bs./in. of notch------0.4 x /8') was tested for flammability according to ASTM A thin bar (5' x 4' x 1/8') of this material was ig D635-44. nited and it burned for fourteen minutes before the fame Example 7 was extinguished. 35 The preceding example was repeated employing 126 Example 3 grams of liquid pre-condensate and 14 grams of partial A charge of 3,9-divinylspirobi (meta-dioxane) (64 phosphite ester additive. The partial phosphite ester was grams), 2,2-(p-hydroxyphenyl)propane (24.6 grams) and 10 percent by weight of the total charge. The reaction. diethyl sulfate (0.39 gram) was heated with stirring for mixture was heated for thirty minutes at a temperature a period of fifteen minutes at a temperature of 110° C. 40 of 110° C. to 115 C., then it was poured into molds The liquid pre-condensate was then poured into molds and cured sixteen hours at a temperature of 150° C. and cured for a period of eight hours at a temperature of The resulting hard, smooth polymer was self-extinguish 150° C. The resulting polymer was a hard, tough, glossy ing within two seconds when a thin bar (5' x 4' x 4') solid. A thin bar (5' x /2' x /8') of the material was was tested for flammability according to ASTM-D635-44. tested for fiammability according to ASTM-D635-44, Example 8 and it burned for eight and one-half minutes before it The preceding example was repeated employing 119 extinguished. grams of liquid pre-condensate and 21 grams of partial Example 4 phosphite ester prepared in the manner of Example 4. A charge of pentaerythritol (408 grams, 3 moles) and The partial phosphite, ester was 15 percent by weight triethyl phosphite (336 grams, 2 moles) was charged to 50 of the total charge. After the reaction mixture was a flask which was fitted with a distillation column. The heated for forty-five minutes at a temperature of 113 mixture was heated to a temperature of 130° C. and C., it was poured into molds and cured for sixteen hours ethanol began to distill off. After two hours of heating at a temperature of 150° C. The resulting polymer was the temperature rose to 160° C. and at this point no more 55 hard, tough, Smooth and glossy and was self-extinguish distillate was evident. The total distillate weighed 232 ing within five seconds when a thin bar (5' x 4' x 1/8'). grams and consisted largely of ethanol and some unre was tested for flammability by the standard method. acted triethyl phosphite. The contents of the flask were Example 9 heated at a temperature of 160° C. for an additional four A charge of 3,9-divinylspirobi (meta-dioxane) (60 hours, and then reaction mixture components were dis 60 grams) and 1,1,3-tris (hydroxyphenyl)propane (30 grams) tilled off which were volatile at a temperature of 150 was heated at a temperature of 110° C. until a uniform C. under a pressure of 2 millimeters of mercury. A vis solution was formed. Pentaerythritol partial phosphite cous, colorless liquid product (451 grams) was recovered ester (4.8 grams) prepared according to the procedure which was shown by elemental analysis to contain 37.64 of Example 4, and diethyl sulfate (0.415 gram) were percent carbon, 7.20 percent hydrogen and 7.80 percent 65 added. The partial phosphite ester was 5.0 percent by phosphorus. The observed molecular weight of the prod weight of the total charge. The reaction mixture was uct was 210, and the equivalent weight was 106 as de heated for a period of nine minutes at a temperature of termined by hydroxyl analysis. The physical constants 100 C. to 105 C., and then poured into molds and of the product indicated that a substantial portion of the cured for ten hours at a temperature of 150° C. The material was a partial phosphite ester having two free 70 hard, glossy polymer which resulted was self-extinguish hydroxyl groups per molecule: ing within two minutes when a thin bar (5' x 4' x 4') HOCEI CEO was tested for flammability by the standard method. c^ Yp (OCH) N Example 10 ... . HOCH2/ CHO 75 A charge of 3,9-divinylspirobi (meta-dioxane) (64 3,010,941 7 8 granus) and 1,1,3-tris(hydroxyphenyl)propane (30 grams) Example 15 was heated until a homogeneous solution was formed. A mixture of 3,9-divinylspirobi(meta-dioxane) (74 Pentaerythritol partial phosphite ester (10.6 grams), pre grams) and 2,2-(p-hydroxyphenyl)propane (34.6 grams) pared according to the procedure of Example 4, and di was heated until a uniform solution was produced, and ethyl sulfate (0.414 gram) were added and the mixture pentaerythritol partial phosphite ester (19.2 grams), pro was heated for ten minutes at a temperature of 110 C. duced according to the procedure of Example 5, was The partial phosphite ester was 10 percent by weight of added. The partial phosphite ester was 15 percent by the total charge. ... After the material was poured into weight of the total composition. Diethyl sulfate (0.56 molds and cured for ten hours at a temperature of gram) was then added and the mixture was heated for ten 150 C., the hard, smooth glossy polymer which resulted O minutes at a temperature of 100 C. and then poured into was self-extinguishing within six seconds when a thin molds and cured for a period of ten hours at a tempera bar (5' x 4' x 73') was tested for fiammability ac ture of 150° C. The hard, glossy polymer which re cording to the standard method. The test was repeated sulted was self-extinguishing within ten seconds when and the flame persisted for eight seconds. tested for flammability according to the standard method. Example 11 What is claimed is: 1. A curable composition comprising 3,9-dialkenyl 3,9-divinylspirobi(meta-dioxane) (69. grams) and 2,2- spirobi (meta-dioxane) having between two and eighteen (p-hydroxyphenyl)propane (34.6 grams) were melted carbon atoms in each alkenyi radical, phenol, and be together and pentaerythritol partial phosphite ester (11.6 tween about 5 percent and 25 percent by weight, based grams) prepared according to the procedure of Example 20 on the total composition weight, of partial phosphite 4, was added. The partial phosphite ester was 10 per ester of pentaerythritol having the formula: cent by weight of the total resin charge. Diethyl sulfate (0.615 gram) was then added and the mixture was heated HOCHY/ CEO YpoR for ten minutes at a temperature of 100° C. After the / / materia was poured into moids and cured for nine hours 25 HO C3 YoHo at a temperature of 150 C., a hard, glossy polymer wherein R is an alkyl group. resulted which was self-extinguishing within ten seconds 2. A curable composition comprising 3,9-dialkenyl when a thin bar (5' x 12' x 1/3') was tested for flam spirobi(meta-dioxane) having between two and eighteen mability according to the standard method. carbon atoms in each alkenyl radical, 2,2-(p-hydroxy 30 phenyl)propane, and between about 5 percent and 25 per Example 12 cent by weight, based on the total composition weight, 3,9-divinylspirobi (meta-dioxane) (74 grams) and 2,2- of partial phosphite ester of pentaerythritol, having the (p-hydroxyphenyl)propane (34.6 grams) were heated formula: until a uniform solution was formed and pentaerythrito O CH CHO partial phosphite ester (19.2 grams), prepared according N to the procedure of Example 4, was added. The partial Y^ POR phosphite ester was 15 percent by weight of the total EO off, YoHo, resin mixture, Diethyl sulfate (0.522 gram) was added, wherein R is an alkyl group. and after heating for ten minutes at a temperature of 40 3. A curable composition comprising 3,9-dialkenyl 110 C, the reaction mixture was poured into molds spirobiCimeta-dioxane) having between two and eighteen and cured for nine hours at a temperature of 150 C. carbon atoms in each alkenyl radical, 1,1,3-tris(hydroxy The hard, glossy, tough polymer which resulted was self phenyl)propane, and between about 5 percent and 25 extinguishing within five seconds when tested by the percent by weight, based on the total composition weight, standard method. 45 of partial phosphite ester of pentaerythritol, having the Example 13 formula: 3,9-divinylspirobi(meta-dioxane) (71 grams), 1,1,3- Hoot, CH.0, tris(hydroxyphenyl)propane (30 grams), pentaerythritol o poR partial phosphite ester (18 grams) and diethyl sulfate HO CH CEO (0.564 gram) were mixed and reacted according to the procedure of the preceding example. The partial phos wherein R is an alkyl group. phite ester was 5 percent by weight of the total resin com 4. A curable composition comprising 3,9-divinyl position. The mixture was heated for a period of eight spirobi(meta-dioxane), phenol, and between about 5 minutes at a temperature of 100 C. and then poured into percent and 25 percent by weight, based on the total molds, and cured for a period of ten hours at a tempera 55 composition weight, of partial phosphite ester of pen ture of 50° C. The resulting hard, brown, glossy poly taerythritol having the formula: mer was self-extinguishing when tested for flammability iO C, CH2O by the standard method and was self-extinguishing within Y^ Dr OR three second when tested a second time, 60 HO off, YoHo Example 14 wherein R is an alkyl group. A mixture of 3,9-divinylspirobi (meta-dioxane) (58 5. A curable composition comprising 3,9-dipropenyl grams) and phenol (16 grams) was treated with 13.6 spirobi(meta-dioxane), phenol, and between about 5 per grams of pentaerythritol partial phosphite ester prepared cent and 25 percent by weight, based on the total com according to the procedure of Example 5 and heated for 65 position weight, of partial phosphite, ester of pentaery five minutes at a temperature of 100° C. The partial thritoi having the formula: phosphite ester was 15 percent by weight of the total com HO C. position. Diethyl sulfate (0.42 gram) was then added Y/ cHo, P OR and the mixture was heated for an additional ten min utes at a temperature of 100° C., and then poured into 70 EO off, YoHo molds and cured for ten hours at a temperature of 150 wherein R is an alkyl group. - a C. The resulting polymer was hard, light brown and 6. A curable composition comprising 3,9-diisopro tough, and was self-extinguishing within five seconds penylspirobi (meta-dioxane), phenol, and between about . . when tested for fiammability by the standard method. 75 5 percent and 25 percent by weight, based on the total

3,010,941 10 composition weight, of partial phosphite ester of pen 10. The process of claim 9 wherein the acidic catalyst taerythritol, having the formula: w is dialkyl sulfate. HOCEI CHO 11. The process of claim 10 wherein said dialkyl sul N/ Yor fate is diethyl sulfate. o / 12. A process for preparing flame-resistant resins which HO off, CEO comprises heating at a temperature between about 100 wherein R is an alkyl group. C. and 150 C. a phenol having at least two hydrogen 7. A curable composition comprising 3,9-di(1-chloro atoms ortho-para to a phenolic hydroxyl group with 3,9- vinyl)spirobi(meta-dioxane), phenol, and between about dialkenylspirobi(meta-dioxane) having between two and 5 percent and 25 percent by weight, based on the total O eighteen carbon atoms in each alkenyl radical in the composition weight, of partial phosphite ester of pen presence of an acidic catalyst to form a partially cured taerythritol having the formula: mixture, and heating at a temperature between about HOC, CHO 100° C. and 150° C. said partially cured mixture with N partial phosphite ester of pentaerythritol having the 15 formula: s IOCH./\ CHO Por HO CH: CEO wherein R is an alkyl group. N 8. A process for preparing resins which comprises heat Yor ing at reaction temperature a mixture comprising 3,9-di / alkenylspirobi (meta-dioxane) having between two and 20 lwherein R is an alkyl group, to form a solid polymer. eighteen carbon atoms in each alkenyl radical, a phenol 13. A curable composition comprising 3,9-dialkenyl having at least two hydrogen atoms ortho-para to a spirobi (meta-dioxane) having between two and eighteen phenolic hydroxyl group, and between about 5 percent carbon atoms in each alkenyl radical, a phenol having at and 25 percent by weight, based on the total composition least two hydrogen atoms ortho-para to a phenolic hy weight, of partial phosphite ester of pentaerythritol hav 25 droxyl group, and between about 5 percent and 25 per ing the formula: cent by weight, based on the total composition weight, of partial phosphite ester of pentaerythritol having the HO or Ch;0, formula: / P OR HOCH CEO 30 HO c CH.0, wherein R is an alkyl group. o, Por 9. A process for preparing flame-resistant resins which Hoc?, CHO comprises heating at reaction temperature 3,9-divinyl wherein R is an alkyl group. spirobi(meta-dioxane), phenol, and between about 5 per 14. The composition of claim 13 cured at a tempera cent and 25 percent by weight, based on the total com 35 ture between 100 C, and 150° C. position weight, of partial phosphite ester of pentaery thritol having the formula: References Cited in the file of this patent HOCH CEO UNITED STATES PATENTS N Yeo R. 40 2,401,776 Rothrock ------June 11, 1946 2,915,499 Wilson et al. ------Dec. 1, 1959 wherein R is an alkyl group, in the presence of an acidic FOREIGN PATENTS catalyst. 588,833 Great Britain ------June 4, 1947 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3, Olo,941 November 28, 196l. Howard R. Guest et al. It is hereby certified that error appears in the above numbered pat ent requiring correction and that the said Letters Patent should read as corrected below. Column 6 line 2 beginning with "A liquid pre-condensate" strike out all to and including "to ASTM-D635-44.''' in line 17, same column 6 and insert instead the following: A charge of pentaerythritol (408 grams 3 moles) and triisopropyl phosphite (4l6 grams 2 moles) was placed in a distillation flask and heated to a temperature of 16O C. At this temperature, the reaction mixture began to reflux and isopropanol began to distill offs After a six-hour reaction period, the tempera ture began to rise and the presence of isopro panol was no longer evident. The reaction mix ture was then stripped by distillation of com ponents, volatile at a temperature of 155 C. under a pressure of 5 millimeters of mercury. A residual product was recovered which weighed 477 grams and had a phosphorus content of ll, 45 - per cent Signed and sealed this list day of May 1962.

(SEAL) Attest: - N ERNEST W SWIDER DAVID L. LADD Attesting Officer Commissioner of Patents