CA1043490A - Fire retardant translucent unsaturated polyesters - Google Patents

Abstract

Abstract of the Disclosure Highly fire retardant unsaturated polyester resins which exhibit low burning rates, low smoke generation and beneficial char formation in the presence of a flame are provided by incorporating up to about 5 weight percent of iron or an iron compound in a halogen containing unsaturated polyester of a polycarboxylic compound and a polyhydric alcohol having greater than about 4 weight percent halogen based on the weight of unsaturated polyester resin and a copolymerizable unsaturated monomer. The unsaturated polyester resins are copolymerized with an unsaturated monomer for use in castings, laminated products and other reinforced articles.

Description

10~3490 Back~round of the Invention Much effort has been expended in discovering and developing useful fire retardant polymer composition systems, and numerous examples of fire retardant polymers have appeared in the literature and some of them are in commercial use. But, the fire retardant re~uirements for polymeric materials have become evermore stringent as technology has become more sophisticated.
Thus, whereas low burn~ng rates were once the sole ob~ective of research for ; fire retardant polymers, now low smoke generation and char formation charac-teristics are also significant.
Concurrently, there has been a desire on the part of plastics fabricators to retain the other beneficial qualities of the base polymer while enhancing the fire retardant properties. But heretofore, efforts to impart fire retardancy to polymer systems has resulted in diminishing the other useful properties. Thus, normally translucent polyester resins have 15 been rendered opaque by the incorporation of sufficient qùantities of antimony trioxide to render the polyester resins sufficiently fire retardant for certain uses.
Accordingly, it is an ohject of this invention to provide superior fire retardant unsaturated polyester resins that not only have low burning ;
rates, but also exhibit low smoke generation when in contact with a flame.
It is also an object of the invent~on to provide superior fire retardant polyester resins that develop a benef~cial, insulating layer of char in the presence of a flame which inhibits further combustion of the polymer It is still another ob~ect of the invention to render unsaturated ~ polyester resins fire retardant without diminishing or deteriorating other -* useful properties of the polymer system.
These and other objects are accomplished by this invention which -is described in detail hereinafter. -

- 2 - ~

, ~'~ ~.' '' , '' "'','.

104;~490 Summary of the Invention The superior fire retardant pol~Y~er compositions of the invention comprise an ~ ethylenically unsaturated polyester of a polycarboxylic compound and a pol~Yhydric alcohol which contains a halogen in a proportion of greater than ahout 4 weight percent, and an effective fire retardant proportion up to about 5 weight percent of iron or an iron compound, wherein the foregoing proportions are based on the weight of the unsaturated polyester and a copolymerizable unsaturated monomer.
The preferred halogen contain~ng polyesters of the invention are those wherein the halogen is provided by a Diels Alder adduct of a hexahalocyclopentadiene and a polycarboxylic com~ound or polyhydric alcohol containing aliphatic carbon-to-carbon unsaturation. The preferred adducts are chlorendic acid or chlorendic anhydride.
Various iron compounds can be employed in the compositions of the ` 15 invention depend~ng on the end results desired. Thus, where it is desired j to retain the translucent character of the unsaturated polyester colorless iron salts can be employed, or ~ron salts that permit the transmission of light when incor~orated in the polyester resin system can be used. The various iron oxides and other iron salts, including various organic iron compounds can be employed.
The unsaturated polyester resin containing the iron compound of the invention is copolymerized with an ethylenically unsaturated monomer, optionally in the presence of a reinforcing agent or filler, to provide the ff nal polyrerized product.
Description of Embodiments ' The Polyesters T~e unsaturated polyesters useful in the invention are generally those commonly known in the art, and are generally the reaction product of a polycarboxylic compound and a polyhydric alcohol.
By polycarboxylic compounds is meant the polycarboxylic acids, polycarboxylic ,, :
., i 104;~4~0 anhydrides, polycarboxylic acid halides, and polycarboxylic acid esters. The unsaturation can be provided in either or both the polycarboxylic compound or the polyhydric alcohol. Suitable unsaturated polycarboxylic acids having aliphatic carbon-to-carbon double bonds, and the corresponding acid halides, esters, and anhydrides can include maleic, fumaric, chloro-maleic, ethylmaleic, itaconic, citraconic, zeronic, pyrocinchoninic, mesaconic, aconitic and acetylene dicarboxylic, either alone or in mixtures.
Illustrative of the unsaturated polyhydric alcohols having aliphatic carbon-to-carbon double bonds, which can be used in providing the unsaturation in the linear polyester molecules are compounds such as butene diol, pentene diol, the unsaturated hydroxy ethers such as allyl or vinyl glycerol ethers, allyl or vinyl pentaerythritol ethers and the like.
The saturated polycarboxylic compounds useful in the prepara-tion of the polyesters can be aliphatic, cycloaliphatic, aromatic or heterocyclic. Illustrative of these polycarboxylic acids, acid halides, .: .
acid anhydrides and acid esters include phthalic, isophthalic, terephthalic, tetrachlorophthalic, tetrabromophthalic, dibromotetrahydrophthalic, chlorendic, adipic, succinic, dichlorosuccinic, and mixtures thereof.
Suitable saturated polyhydric alcohols for use in the preparation of the polyester resins include ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, butane diol, pentane diol, hexane diol, dibromoneopentyl glycol, 1,4-cyclohexane dimethanol, glycerol, mannitol, sorbitol, bisphenols, substituted bisphenols, hydrogenated bisphenols and mixtures thereof.
.' ~, ', " ' ~.
l~ -.. ~'. '.,' `
i - 4 ~, '."
, '.
.., .' '.
: .....
' ....

1043~90 The properties of the polyester resins can be modified by the incorporation of suitable monofunctional carboxylic compounds and alcohols.
Illustrative examples of such compounds are 2,2-dichloroethanol; 1,1-dibromo-2-propanol; 2,2,2-tribromoethanol; 1,1,3,3-tetrabromo-2-propanol;
1,1,1-trifluoro-2-propanol and 2,3-dibromo-1-propanol. An example of a carboxylic compound is pentachlorophenoxy acetic acid.
The properties of the polyesters can be varied by using mixtures of the ~ar~ous types of acids and alcohols, such as an unsaturated acid, a saturated acid and a saturated alcohol.
The preferred unsaturated polyesters of the ~nvention contain etther an adduct of hexahalocyclopentadiene and a polycarboxylic compound containing aliphatic carbon-to-carbon unsaturation or an adduct of hexa-halocyclopentadiene and a polyhydric alcohol containing al~phatic carbon-to-carbon unsaturation. The preferred unsaturated polyesters are the reaction products of a polycarboxylic adduct of hexahalocyclopentadiene, i another carboxylic compound containing carbon-to-carbon unsaturation and a polyhydric alcohol. Such a product is disclosed and claimed in U.S.
Patent 2,779,7nl, issued January 29, 1957. Other methods for incorporating either a polycarboxylic or polyhydric alcohol adduct of hexahalocyclo-pentadiene include: tl) the reaction of a polycarboxylic adduct of hexa-halocyclopentadiene, an unsaturated polyhydric alcohol containing aliphatic carbon-to-carbon unsaturation, disclosed and claimed in U.S. Patent 2,863,794, issued December 9, 1958; (2) the reaction of a polyhydric alcohol adduct of hexahalocyclopentadiene with a polycarboxylic compound containing aliphat~c carbon-to-carbon unsaturation disclosed and claimed in U.S. Patent 2,779.700, issucd January 29, 1957; and (3) the reaction of a polyhydric alcohol adduct of hexahalocyclopentadiene with another alcohol containing aliphatic carbon-to-carbon unsaturation and a polycarboxylic acid, disclosed ~ 5 . ~:. .--t ~,*, :~

~ .

lV43~90 and claimed in U.S. Patent 2,863,795, issued December 9, 1958. An alternate method for incorporating an adduct of hexahalocyclopentadiene into a polyester resin involves reacting an unsaturated polyester resin with a copolymerizable compound containing an adduct of hexahalocyclopentadiene, such as disclosed and claimed in U.S. Patent 2,783,215, issued February 26, 1957. The polyester resins containing the polycarboxylic and polyhydric alcohol adducts of hexahalocyclopentadiene can be modified by incorporating therein saturated carboxylic acids and anhydrides, as disclosed and claimed in U.S. Patent 2,8~0,144, issued ~une 9, 1959, and U.S. Patent 2,898,256, issued August 4, 1959. When used in this specification, the tenm poly-carboxylic compound refers to the polycarboxylic acids, acid anhydrides, acid halides and acid esters, of either the aliphatic or aromatic type.
Among the adducts of hexahalocyclopentadiene and polycarboxylic compounds which may be used are: 1,4,5,6,7,7-hexachlorobicyclo-(2.2.1)-5-heptene-2,3-dicarboxylic acid and anhydride, also known as chlorendic acid and anhydride; 1,4,5,6,7,7-hexabromobicyclo-(2.2.1)-5-heptene-2,3-dicarboxylic . acid; 1,4,5,6,7,7-hexachloro-2-methylbicyclo-(2.2.1)-5-heptene-2,3-dicarboxylic anhydride; 1,4,5,6,7-tetrachloro-7,7-difluorobicyclo-(2.2.1)-S-heptene-2,3-dicarboxylic acid; 1,4,5,6,7,7-hexachlorobicyclo-(2.2.1)-5-heptene-2-acetic-2-carboxylic anhydride; 5,6,7,8,9,~-` hexachloro-1,2,3,4,4a,5,8,8a-octahydro-5,8-methano-2,3-naphthalene -dicarboxylic acid and anhydride; 1,2,3,4,5,6,7,7-octachloro-3,6-methano-1,2,3,6-tetra-hydrophthalic acid and anhydride; 2,3-dicarboxy-.~ .. .. .
5,8-endomethylene-5,6,7,8,9,9-hexachloro-1,2,3~4,4a,5,8,8a-octahydronaphthalene ~' 25 anhydride; 2,3-bis(ethylene carboxy~-1,4,5,6,7,7-hexachlorobicyclo(2.2.1) S-heptene; and 1,4,5,6,7,7-hexachlorobicyclo-(2.2.1)-5-heptene-2,3-dicarbonyl chloride. --Among the adducts of hexahalocyclopentadiene and polyhydric alcohots which may be used are: 1,4,5,6,7,7-hexachloro-2,3-bis-:
~ - 6 - ~

.- '; .

. . .

hydroxymethylbicyclo-(2.2.1)-5-heptene; 1,4,5,6,7,7-hexachloro-2,3-bis-hydroxymethylbicyclo-(2.2.1)-2,5-heptad~ene; 3-(1,4,5,6,7,7-hexachlorobicyclo-(2.2.1)-5-heptene-2-yl)-methoxy-1,2-propaned101;
1,4,5,6-tetrachloro-7,7-difluoro-2,3-bis-hydroxymethylb~cyclo-(2.2.1)-5-heptene; 1,4,5,6,7,7-hexabromo-2,3-b~s-hydroxy-methylbicyclo-(2.2.1)-5-heptene; 3-(1,4,5,6-tetrachloro-7,7-difluorobicyclo-(2.2.1)-5-heptene-2-yl)-methoxy-1,2-propane diol. These compounds and methods of preparat~on are disclosed ~n U.S. Patent No. 3,007,958, ~ssued November 7, 1961.
It is also w~thin the scope of the invention to use other halogen-conta~ning polyesters such as those der~ved from tetrachlorophthalic acid or anhydride. and tetrabromophthalic acid or anhydrlde.
The halogen can be provided in the polyesters of the invention by a combination of the foregoing methods. Thus, an unsaturated polyester can be prepared using a halogenated dibasic acid such as chlorendic acid, and a monobromlnated alcohol such as dibromopropanol.
The polycarboxylic compounds and polyhydric alcohols requ~red ~; in the production of the foregoing halogen-containing adducts and polyesters ~-can be provided by using any of the compounds disclosed hereinbefore.
The temperature for the reaction between polyhydric alcohols and polybasic acids ranges from about one hundred to two hundred degrees centigrade, although higher or lower temperatures can be used. Esterifica-tion catalysts such as para-toluene sulfonic ac~d, benzene sulfonic acid, beta-naphthalene sulfonic acid and the like, or amines such as pyridine, tr1ethyl amine, quinollne and the like can be added to the reaction mixture.
The proportion of polyhydric alcohol is approximately controlled by the t i - 7 -' ' :, , :
,: 'J ~'.' ,, ' '' ., . , ' " ' total mole proportion of acids in the ester~fication reaction mixture. It is also preferred to react the polyhydr~c alcohols and polybas~c ac~ds ~n rou~hly equ~molar proport~on; however, e~ther the ac~ds or alcohols can be used ~n substant~al excess, if ~t is des~red to form a low molecular we~ght polyester res~n.
Unsaturated Monomers A var~ety of ethylen~cally unsaturated monomers can be used for cur~ng or cross-l~nklng the ethylen~cally unsaturated polyesters. It ~s generally preferred that add~t~on polymer~zation be pract~ced s~nce no by-product ammonla or water ~s fonmed, and the problems result~ng therefrom ;i are not exper~enced. The v~nyt~dene monomers useful ~n cur~ng the thermo-plast~c unsaturated polymers include v~nyllc compounds or m~xtures thereof capable of cross-l~nk~ng ethylen~cally unsaturated polymer cha~ns at the~r po~nts of unsaturat10n. Usually they contain the reactive groups H2C=C< .
Speclf~c examples include styrene, chlorostyrenes, methyl styrenes such as alpha methyl styrene, p-methyl styrene, vinyl benzyl chlor~de, d~vinyl benzene, ~ndene, unsaturated esters such as: methyl methacrylate, methyl acrylate and other lower al~phat~c esters of acrylic and methacrylic ac~ds, allyl acetate, d~allyl phthalate, diallyl succ~nate, d~allyl adipate, -d~allyl sebacate, d~ethylene glycol b~s(allyl carbonate), trlallyl phosphate -and other allyl esters, and v~nyl toluene, d~allyl chlorendate, d~allyl tetra-chlorophthalate, ethylene glycol d~acrylate, ethylene glycol d~methacrylate, ethylene glycol d~ethacrylate, and mtxtures thereof. The monomer may be ;
~ ddm~xed ~n the polymer ~n an amount suff~c~ent to produce a thermoset 25 polymer and the adm~xture heated to an elevated temperature in the presence ` of a su~table catalyst to cross-l~nk or cure the polymer. With proper catalyst systems such as cobalt naphthenate and methylethyl ketone perox~de, room temperature cures are obta~ned.
f .~ .

lV43490 The cross-linking agent can be advantageously co~bined with the poly~erizable polyester while the unsaturated polyester and the olefinic cross-linking agent are at an elevated temperature thereby facilitating solution and mixing. To prevent premature polymerization at this stage, a polymerization inhibitor is advantageously added to the mixture, or preferably to one of its components prior to mixing, especially if the mixture is to be stored or shipped in commerce prior to curing. Alterna-tively, or in addition to including a polymerization inhib~tor, a catalyst and/or promoter for the copolymerization may be added, particularly if it ~s desired to make available in commerce a composition which is ready for polymeri2ation and does not require further chemical additions in order to be used, as ls commonly known in the art.
The polymerization inhibitors generally are added in the order of 0.001 to 1 weight percent of the mixture. Among the inhibitors which may advantageously be employed to prevent the premature polymerization of the mixture of polymerizable polyester and olefinic cross-linking agents, particularly if the mixture is to be stored or shipped in commerce prior to curing, are substances such as hydroquinone, benzoquinone, para-- tertiarybutyl catechol, para-phenylene diamine, trinitrobenzene, picric acid, and the like. ~ -~ The proportion of olefinic cross-link~ng agent to unsaturated ~~ polyester can be varied within the ultimate limits of each without departing from the scope of the invention, necessary to produce an infusible, ~ lnsoluble, polyester resin. In general, the concentration of the unsatu-; 25 rated polyester in the olefinlc cross-linking agent can vary between

3 about ten and nlnety percent. Polymerization catalysts are preferably ; added to the mixture of unsaturated polyester and olefinic cross-linking g "
~r;

: ' :
"'''' '~

agent to effect setting or curing. Catalysts such as benzoyl peroxide, acetyl peroxide, lauryl peroxide, methylethyl ketone peroxide, cumene hydroperoxide and the like are satisfactory. Such catalysts are used in proportions of 0.01 to ten percent of the total resin, depending on the efficiency of their action and whether or not substances which inhibit polymerization are present in the mixture. The polymerizatlon reaction can also be hastened by adding promoters such as metals or metal salts, cobalt resinates, cobalt maleate, cobalt naphthenate and the like, or amines such as dibutylamine, or mercaptans such as dodecyl mercaptan.
These are used in proportions similar or smaller to that stated for the catalysts.
The Iron Compounds In the preparation of translucent polyester laminates and other products of the invention, iron salts that permit the transmission of -~ 15 11ght when incorporated in the cured polyester are employed. Sultable iron salts are the colorless iron salts such as ferric sulfate hydrates.
Other suitable salts which permit light transmission in the cured polyester include ferrous hydroxide, ferrous sulfate, ferrous tartrate, ferrous stannate, ferrous chloride, ferrous ammonium sulfate, and the like.
Other substantially insoluble iron compounds that can be used in accordance with the invention include ferric acetate, ferric formate, ferric borate, ferric tungstate, ferric Yanadate, ferric molybdate, fer- ;
rous tungstate, ferric oxalate, ferric ferrocyanide, ferr~c chlorendate, and ferric hexachloronorbornene carboxylate.
Also useful in the compositions of the invention are the lron oxides, such as Fe2n3 (yellow and red iron oxide), Fe304 and FeO.

.: ' .~ .

: '. . .
. ~ ;
. . '' ' -' .

,' ~ .
., . . ,. ,. ... , . , ., . : : :
,` . ' , ' ` ' . . ' ' . , . " ! .. . ...

The iron com~ound~ named hereinabove are suhstantially insoluble in the polyester when admixed with a copolymerizable unsaturated monomer.
Also useful are iron compounds that are soluble in the admixture of poly-ester and copolymerizable unsaturated monomer, but which are free of S iron-to-carbon bonds.
Useful soluble iron compounds include the metal or metalloxy beta-ketoenolates of the formula:

R2 1 ~ M
R3 - C o / n ; ~n which M is an iron ion, an ironoxy ion, or an iron hydroxy ion, in which n is an integer equal to the valence of the iron, ironoxy ~on or iron hydroxy ion, in wh~ch each of Rl and R3 is a substituent selected from the group consisting of hydrogen and an or~anic substituent selected from alkyl, aryl, cycloalkyl, aralkyl, alkaryl, alkoxy, and aryloxy having one to eight carbon atoms and wherein each aryl substituent is carbocycl~c, and in which R2 is selected from the group consisting of Rl, R3, halogen, nitro, and sulfo. Typical beta-ketoenolates are the ferrous or ferric acetylacetonates.
Other soluble iron compounds include the iron carboxylates, particularly der~vatives of carboxylic acids for example of about 3 to 22 carbon atoms. Illustrative iron carboxylates are iron acrylate, iron oleate, iron naphthenate, iron stearate, iron laurate, iron linoleate, and the like.
~, 25 Other iron compounds which have desirable fire retardant proper-ties but which adversely affect the stability or the cure of the polymer compositions can be employed if such iron compounds are used in an inactive .
form such as encapsulated or reacted or complexed with another compound. Such iron compounds are ferric chloride and ferric oxychloride. These compounds -,~ ~
1 1 . ' ... . . .
-'' ' .

~' .. .
,, . , . . - . . , ... - ..
. , . . ... , , , . ~, ... ., lV4~90 can be encapsulated Wit~l qelatin or other polymeric materials. Alterna-tively, the compounds can be reacted or complexed with nitro compounds or aromatic ethers or amines. ~n example of a suitable co~pound is an amine salt of ferric chloride.
The metallic iron and insoluble iron compounds are incorporated into the polyesters in ftnely divided form. Preferred are particles passing through a 200 mesh standard sieve. Where translucent plastics are desired, the particu~ate iron or iron compounds should not contain a sufficient quantity of fine particles around the wave length of light, i.e., about 0.1 to 1 micron, to cause undesirable light scattering and resultant decrease in translucence. In practice, it has been observ~d that iron compounds pulverized to pass completely through a 325 mesh screen contain -sufficient fine particles to reduce translucency of the polyester.
The iron or iron compounds are ~enerally incorporated in the , ~ ~ .....
lS compositions of the invention in a proportion up to about 5 weight percent of iron or iron compound based on the weight of the unsaturated polyester ` and the copolymerizahle unsaturated monomer. Preferably, the proportion -~, of iron or iron compound is in the ran~e of about 0.5 to about 2 weight percent of iron or iron compound based on the weight of unsaturated polyester resins and monomer.
The unsaturated polyester resins of the invention generally contain greater than ahout 4 weight percent up to about 40 weight percent of halogen based on the weight of the unsaturated polyester resin and the copolymerizable unsaturated monomer. The proportion of halogen is preferably greater than 15 weight percent when the halogen is chlorine.
For best results, the compositions of the invention are phos- -, phorus-free, i.e., exclude phosphorus and compounds of phosphorus.

;, . .. .
' - 12 -., ': '~ .
", - .
., ' - . .

,.',' ':

1(~43490 Phosphorus tends to neutralize the synergistic effect of the iron on the halogen moiety. The compositions of the invention also exclude ferrocene and related compounds that have iron-to-carbon bonds. The compositions of the invention prnvide very effective fire retardance without the need for antimony trioxide which is so often used in commercial formulations to achieve low burning rates. The exclusion of antimony trioxide is especiall,y preferred when it is desired to retain the translucent character of the polyester resins of the invention. The iron compounds and halogen component of the polyester can be the sole fire retardant agents present in the compositions of the invention.
The Curinq Process i ;
The polymeri2ation conditions for effecting the cross-linking reaction between the unsaturated polyesters of this invention and the ; olefinic cross-linking agent may be selected from a wide variety of ' lS techniques but usually involve the application of heat or light. Although pressure is not a required condition for effecting polymerization of the polymerizahle mixtures embraced within this invention, it is sometimes advantageousl~y employed, particularly when it is desired to make laminates in preformed shape. The pressures found satisfactory for this purpose are relatively low compared to those required for molding or laminating other type resins than involved herein and may be of the order of that obtained by pressing glass plates having a fiber glass mat or laminate impregnated with the polyester resin sandwiched therebetween.
The temperature at which polymerization is effected depends on ; 25 a variety of factors, particularly the boiling point of the olefinic cross-linking agent and the exothermic characteristics of the polymer- -ization mixture. A temperature is selected which will give a suitable ; ~
- 1~ - ', ~ .

- ..
:.

.. , . . . ~ , .. .. ..

1(~434~0 reaction rate and yet not cause substantial volatilization, and in the case of producing very thic~ castings, which will not produce a product which is crack-crazed.
The properties of the compositions of this invention can be varied substantially by incorporating modifying agents before, during or after any of the processing steps employed. For example, instead of producing articles of commerce from the compositions of this invention which are in the form of castings or laminates as previously described herein, a fnamed type article may be made by incorporating a small ~ -percentage of a foaming agent such as sodium bicarbonate into the solu-tion of unsaturated polyester dissolved in mono-olefin and thereafter effecting the copolymerization in the presence of catalyst and heat to produce the foamed article. Formulations which are useful for making moldings embodying the compositions of this invention may be made by mixing into the unsaturated linear polyester and olefinic cross-linking agent mixture, an inert filler such as chopped fiber glass rovings, macerated fabric, asbestos fibers, mica, etc., which serve as fibrous reinforcing media and incorporating a small percentage of a mold lubricant, catalyst and/or promoter. Auxiliary fire retardant additives such as hydrated alumina can be used to add to the fire retardance provided by the halogen and iron.
It is to be understood that dyes, pigments, plasticizers, lubricants and various other modifying agents are contemplated as being incorporated in certain formulations to produce compositions embraced in - ;
` this Invention in order to obtain or accentuate any given property.
The following examples are presented to illustrate this inven-tion. It is to be understood that the examples are not to be construed , as limit1ng the invention. In this specification and claims, all tempera- - `~
tures are in degrees centigrade and all parts are by weight, unless other-wise indicated. `
'~ '."'; . ~.

'~ ;.
.' :'.

- , . , .. ,.. ,., .; -. . . . ... .

E~ f~ Pol~esters Example 1 (Resin I) An unpolymerized li~uid unsaturated polyester resin was prepared by esterifying about 53 parts of ethylene glycol and 90 parts of diethylene glycol with about 395 parts of 1,4,5,6,7,7-hexachlorobicyclo-(2.2.1)-5-heptene-2,3-dicarhoxylic anhydride and about 71 parts of maleic anhydride.
About 3n parts of styrene and ahout 70 parts of product produced by the esterification reaction were mixed togetller until complete solution was obtained to give a clear, suhstantially colorless solution of liquid polyester resin having a viscosity of about 30 poises at 25 degrees centigrade on a Gardner bubble viscometer and hav~ng a chlorine content of about 30 percent by weight of the total.
Example ? (Resin II ) An unpolymerized liquid unsaturated polyester resin was prepared by esterifying about 76 parts of propylene glycol with about 128 parts of 1,4,5,6,7,7-hexachlorobicyclo-(2.2.1)-5-heptene-2,3-dicarboxylic acid and ~,.
about 66 parts of maleic anhydrlde. About 45 parts of styrene and about 55 parts of product produced by the esterification reaction were mixed together until comp1ete solution was obtained to give a clear, substantially colorless solution of liquid polyester resin having a viscosity of about 19 poises at 25 de~rees centigrade on a Gardner bubble viscometer and having a chlorine content of about 19 percent by weight of the total.
Example 3 (Resin III) An unpolymerized liquid unsaturated polyester resin was prepared by esterifying about 250 parts of propylene glycol with about 245 parts of fumaric acid and about 304 parts of tetrachlorophthalic anhydride. About -15- ~ :

.'. ~ .
~' 28n ~arts of styrene were mixed with the esterification product until com-plete solution was obtained to ~ive a clear substantially colorless solution of liquid polyester having a viscosity of about 20 poises at about 25 degrees centi~rade on a Gardner bubble viscometer and having a chlor1ne content of about 15 percent.
Example 4 (Resin IV) An unpolymerized liquid unsaturated polyester resin was prepared by esterifying about 20 parts of diethylene ~lycol and about 140 parts of ethylene glycol with 11~ parts of maleic anhydride, 56 parts of phthalic ln anhydride, 38n parts of tetrabromophthalic anhydride and 3 parts of sodium acetate. About 275 parts of styrene and 0.1 part of hydroquinone were mixed with polyester until complete solution was obtained to give a clear, substantially colorless solution of liquid polyester having a viscosity of about 10 poises at 25 degrees centigrade on a Gardner buhble viscometer and having a bromine content of about 25 percent.
Example 5 (Resin V) A mixture of 194.5 parts (0.5 mole) of chlorendic acid, 98.1 parts (1.0 mole) of maleic anhydride, 217.9 parts (1.0 mole) of 1,2- ~ -dibromopropanol and 24.~ parts (0.40 mole) of ethylene glycol and 36.8 parts (0.40 mole) glycerol were heated, under a steady nitrogen sparge, to and maintained at about 165 degrees, while collecting the water formed as a . , .
distillate. After about 12 hours, the acid number of the reaction mixture had decreased to 46. A small quantity, about 0.10 part, of tolylhydro-quinone was added to the mixture and the reaction was continued for an . 25 additional fnur hours at which time the acid number was about 34. The resultant polyester product was analyzed and found to contain 26.0 percent ~ bromine, 2n.0 percent chlorine and the average molecular weight of the - polymer chains was 1150. An amount of styrene equivalent to about one - ~ -? .- :-, - 16 _ , 16)43490 third the wei~ht of the ~olyester mass was added to the hot mass and the resultant solution was cooled to ambient temperature. The viscosity (Brook-field) of the solution was 1620 cps at 25 degrees.

Exam~les_6 to 10 Tahles I through V below show the results of fire retardance tests by the ASTM D-757-65 test method on castings of the resin prepared as de-scribed in Examp1es 1 to 5, (Res~ns I to V, respectively). The cast~ngs were prepared by mlxing lnO parts by weight of resin with iron compound in the amount indicated in the tables, 0.2 part of 12 percent cobalt octoate, and such other addit~ves as are indicated in the tables. After at least `~ 10 minutes' stirring to assure unlform dispersion of the ~mm~scible materials, the catalyst, methyl ethyl ketone peroxide (60X in dimethyl phthalate), 1 part was added, stirred for 1 to 2 minutes, and then the mixture was allowed to cure at 25 degrees centigrade for 16 hours and at 65 deqrees centigrade for 8 hours. The castings were then removed from the mold, cut into specimen bars for testing by ASTM D-757-65 test method, for smoke by ASTM D-2843-70, and for heat deflection temperature (identlfied in the -tables as "HDT"), by ASTM D-648-72 test method. Data on light absorption ~ ~ -due to smoke obscuration was acquired by a computer wh~ch printed out the -li~ht absorption and percent smoke at one second intervals. The "Smoke Density Rating" of this modification of the ASTM test is the percent smoke at 60 seconds. Samples wh k h were used for the ASTM D-648-72 test measured 0.5 inch x 0.5 inch x 0.125 inch.
, ~ .

, . .
. , ~ - 17 - ~ ~

' '.' ' " : .
. .

.~, . .

CO ~ . ~ '`
~ _ ~ ~ ~ ~ .

l~aa 8 C o ~ ~ ~t U>

,., ._ ,. ., vl a ~ . . .
r ~¦ ~ ~ ~~ ~ ~

~ C~ ;
2 i~ .Y ~1 c E N O o O o o _ _ o o o g O o o o o Oo o :
.~ ~ oooooooooooooooooooo ~' ` I ~' E ¦ U') oo a~ ) C~ ~D o o ~ o o co co o ~ OD ~ 0 oo ~D o ,;~ C ;i. .`
s ~ ~ N u~ o _ ~ o O O -- -- -- ~ ~

3 3 3 ~ x x ~ ` `.;

_ ~ 8 U âl â~
1~ E EO O o o O O O o o o o X o X o o c~
; ¦ O ~ ~ ~ L ~ ~ ~ ~ ~ L ~ .

Z~ ~ ~ ~ Y ~ = O ~ V 1~
`J `-. ~ , ~ . .
~ - 18- ~ ' . .
,-.

I
~1 ~a~
~y G O CO
Q ~
~ a ~ .' V~

a o ~
r _ ~ ~D O CO ~ ~o ~ O _ ~) o O ~ ~ ~ O O U~ -. .' j~ ~_ ':
.C
E-- N ~ ~ -- C ~ _ O . --.
3 _ o o o o o o o o o o o o o o o o o o o o o _ . , _ -.:

~ . .':
S
C~ Y Ln U~
~ -- -- ~ ~ O N O ~Y) N _ N ~ _ _ _ _ N ~ -- N

O--2 ~ ~ ~ o ~ ~ ' = c o ~ o ~C LL___L~_~_X~ L' LLL-L LLL~LL~OOO~-Lg-~-~
LLLLLLLLLLLLL L L

C , ' : ' ~' ~z ~3X-~ ~ zo .:

.' ~' .

:: ':
- 1 8a - ~

,. .~. ~
~ :, 1043f~90 8;~ , u ~ ~ æ o ~ O G '~ o~

C ~lC~ 3 ~

~3 E~ ~ ~ F c u~
~¦ ~ m-- o o o ~1 3~

~, la L¦ _ N ~ 3 ~¦ C~

" & ~ 3 ~ "

o ~ 2 ~ulC a~ c~

., 19- -,, ~,,, ' ` ~;
.. , , ,. " ` , . ,, . . . . ~
., .

1()43490 o o o ~o o ~ o o o o o o o E~ . . ~ ~ ,~ t~ c~ '`o o~ 'o`
3 o o a~ ~ ~ co o o o o o o o E ol ~ .... L~ ~ ~ E E ol E~ o~ E~

L ~ c c e ~ o t E t ~

,,g=¦cO æ O ~ ,~0 C=lC ~

- 20- ~ ~

.. . . ..

~y , . , ., , . , ~, .. , , . , .. , . ., .; , .... . , ~ , 1()4 39~
In the testing of synergism with Resin V, it was seen in Table V
that the D-757 test was insufficient in differentiating synergistic effects of iron and antimony compounds. The samples that contained levels of l percent or more of fire retardant additives did not ignite, so the "burning rate" which was variable and poorly reproduc~ble, was really a "charrin~ rate". It is often preferable in fire retardant plastics to ohtain a rap~d charring material (that can insulate against the heat source) rather than a slow-charring material. (See for instance, "Flammabil~ty of Plast~cs III," Learmonth and Thwaite, Br~tish Polymer Journal, 2, 104, (1970).
Resin Y materials were therefore evaluated by another method than the ASTM D-757 Test. Samples of material were heated at lO degrees centigrade per minute while the weight loss of the samples was observed cont1nuously by the thenmogravimetric analysis technique. Results are shown in Table VI. At low rates of heating to 600 degrees centigrade, it was observed that there was little change in weight loss after the ~, samples had reached 400 degrees centigrade. It was observed that Resin V
lost weight more rapidly than Resin I which is consistant with the lower !' Time to Flameout of Resin V. With l percent iron oxide added to Resin V, it was observed that weight loss occurred much more rapidly and that a 30 percent weight loss had already occurred at 264 degrees as compared to a comparable we~ght loss at 308 degrees for Res~n V without additive ' or with antimony ox~de. The addition of iron oxide also catalyzed the ~formation of a large char residue (47X) which made less material available -for gaseous fuel and less material available for smoke formation. From ~ --these data it is concluded that under flaming conditions where Resin V
~ , .
.~ 21 , ', ~`

,,1 ' ~ .

., :., . ~ .
:
.

il~4;~490 is ex~osed to conditions of extremely rapid temperature rise, neither the addition of iron compounds nor antimony compounds will improve the fire retardant and low smoke properties much; but in oven-like conditions where the temperature rise to the flaming condition is slower, the Resin S V compositions that contain a synergistic amount of iron compound willgive improved fire retardance and low smoke properties.
TABLE VI
Synergism in Wei~ht Loss on Heating (10/min) of Resins I and V
Char We~ght Res~d~e, ~ Temperature, C
Resin _ditive Percent 400 C 30X Wei~ht_Loss V None -- 18 308 V Iron oxide 1 47 264 V Antimon~y oxide 5 16 313 I None -- 36 327 lS Example 11 - Resin-Soluble Iron Compounds as FR Synergists Compounds of iron that are soluble in styrenated resin composi-tions, such as Resins I-V, are also effective fire retardant synerg1stic components with halogens. Examples of such a soluble compound, ferric - acrylate, are shown in Table I, Casting Nos. AN and A0.
Soluble iron compounds in the resin can cause effects on the peroxide-initiated cure of the resin to a greater degree than the in-soluble compounds. Ferric acetylacetonate, for instance, accelerates the methyl ethyl ketone peroxide initiated cure of Resin I so that no cobalt octoate is required to obtain a room temperature cure. Polymeriza-tion inhibitors may be added, such as chloranil and t-butyl catechol, to obtain sufficientlY long pot life.
. .''.

- 22 - ~

., ~ ' ~' ,.
.:

11143490 -:
Resin ~, 130 parts; dibromopropyl hydroxyethyl fumarate, 7 parts;
styrene, 6 parts; chloranil, 0.02 parts; t-butyl catechol, 0.01 parts; and methyl ethyl ketone peroxide, 1 part were blended to provide a polymerizable mixture which had a gel time at 25 de~rees centigrade of 30 minutes. The composition was tested as in the preceding Examples 6 to 10 and found to give the results shown in Table YII.
TABLE VII
Fire Retardant Synergism of Iron Acetylacetonate in Resin I

10 Cast~ng Weight HDT Burn Rate Flameout.
No. Compound Percent C ~ Time(secs GA None 98 0~17 180 GB Iron Acetyl-acetonate 1.5 70 0.07 0 Example 12 - Iron-Phosphorus Interaction in FR Polyesters It has been observed that iron compounds are antagonistic with compounds of phosphorus, such as triethyl phosphate, in the fire retardant ~ -~ resins of our invention. Iron compounds of phosphorus are also inactive ! as shown in Table VIII. Testing was conducted in accordance with the ~ 20 procedure of Examples 6-10.

's ,'; '"` -.~ ~
'' ~''' ., . :
, TABLE VIII
.
Inactive Iron-Phosphorus Compounds in Resin I

Casting Weight oDT Burn Rate Flameout tlo. Com~ound Percent C (in/min) Time(secs¦
HA None 115 0.20 160 HB ~Ferric ~lycer-ophosphate 1 114 0.21 155 HC Ferrous phosphate 1 113 0.20 107 ; HD Ferrous phosphate 2 111 0.21 180 ' HE Ferrous phosphate 4 112 0.19 160 '~ 15 HF Ferric phos-phate 2 84 0.20 147 HG Ferric acetyl-acetonate and 1.75 ~ 62 0.25 170 phate P 5 J
.:
The foregoing specification is intended to illustrate the : ;
invention with certain preferred embodiments, but it is understood that the details disclosed herein can be modified without departing from the splrit and scope of the invention.

.
:' ` .. ' ' ':

'i . :

.
- 24 - . ; ~-. .
. ' .' ' , ' ., ' .

`' ~ ':' , .. .. . , " , ,, ,, . ~ . . . .

Claims (32)

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A fire retardant polymer composition comprising an .alpha.,.beta.-ethylenically unsaturated polyester of a polycarboxylic com-pound and a polyhydric alcohol, said polyester being effective to copolymerize with an unsaturated monomer to produce an infusible insoluble polyester resin, said unsaturated polyester containing a halogen in a proportion of greater than about 4 weight percent, and an effective fire retardant proportion up to about 5 weight percent of iron, an iron compound that is insoluble in said unsaturated polyester when admixed with the copolymeri-zable unsaturated monomer, or an iron compound that is soluble in said unsaturated polyester and monomer but which is free of iron-to-carbon bonds, said composition being substantially phosphorus-free, the proportions being based on the weight of the unsaturated polyester and the unsaturated monomer to be copolymerized therewith.

2. The composition of claim 1, wherein said halogen is present as a halogen containing polycarboxylic compound.

3. The composition of claim 2, wherein said halogen is chlorine.

4. The composition of claim 2, wherein said polycarboxylic compound is chlorendic acid or chlorendic anhydride.

5. The composition of claim 2, wherein said polycarboxylic compound is tetrachlorophthalic anhydride.

6. The composition of claim 1, wherein the halogen is bromine.

The composition of Claim 2 wherein said polycarboxylic compound is tetrabromophthalic anhydride.

The composition of Claim 1 wherein said halogen is chlorine and bromine.

The composition of Claim 8 wherein said halogen is present as chlorendic acid or anhydride and dibromopropanol.

The composition of Claim 1 wherein said iron compound is an essentially colorless iron salt.

The composition of Claim 10 wherein the iron salt is ferric sulfate.

-12-The composition of Claim 1 wherein said iron compound is an iron salt that permits transmission of light when said polyester is copolymerized with an unsaturated monomer.

-13-The composition of Claim 12 wherein said iron salt is ferrous sulfate.

-14-The composition of Claim 12 wherein said iron salt is ferric acrylate.

The composition of Claim 1 wherein said iron compound is an iron oxide.

The composition of Claim 15 wherein said iron oxide is yellow iron oxide Fe2O3.

-17-The composition of Claim 1 wherein said iron compound is an insoluble compound.

-18-The composition of Claim 17 wherein said iron compound is ferric acetate.

-19-The composition of Claim 17 wherein said iron compound is ferrous tartrate.

-20-The composition of Claim 17 wherein said iron compound is ferric tungstate.

-21-The composition of Claim 17 wherein said iron compound is ferric borate.

-22-The composition of Claim 17 wherein said iron compound is ferric molybdate.

-23-The composition of Claim 1 wherein said iron compound is a soluble iron compound that is free of iron-to-carbon bonds.

-24-The composition of Claim 23 wherein said iron compound is ferric acetylacetonate.

25. A copolymerizable mixture of the composition of claim 1, and a copolymerizable ethylenic monomer.

26. The mixture of claim 25, wherein said monomer is styrene.

27. The mixture of claim 25, when copolymerized to an infusible product.

28. The composition of claim 25, when mixed with an inert filler and copolymerized to an infusible, insoluble product.

29. The composition of claim 25, when mixed with a rein-forcing agent and copolymerized to an infusible, insoluble reinforced product.

30. A liminated article comprised of copolymerized sheets of the composition of claim 25, admixed with a reinforcing agent.

31. A translucent, fire retardant polymer composition com-prising an unsaturated polyester of chlorendic acid or anhydride, an unsaturated dicarboxylic acid or anhydride and a polyhydric alcohol, said polyester being effective to copolymerize with an ethylenically unsaturated monomer to produce an infusible, insoluble polyester resin; said unsaturated polyester containing chlorine in a proportion of greater than about 20 weight percent and about 0.5 to about 2 weight percent of an iron compound that is insoluble in said unsaturated polyester when admixed with the copolymerizable, ethylenically unsaturated monomer and permits transmission of light when said unsaturated polyester is copoly-merized with the copolymerizable, ethylenically unsaturated monomer; the proportions being based on the weight of unsaturated polyester and copolymerizable unsaturated monomer to be copoly-merized therewith.

32. The composition of claim 31, wherein the iron compound is ferric sulfate,