US3809681A - Brominated bisphenol a diethanol polyformal - Google Patents

Abstract

DISCLOSED IS A BROMINATED BISPHENOL A DIETHANOL POLYFORMAL COMPRISED OF ERECURING UNITS OF THE STRUCTURE

-O-CH2-CH2-O-((BR)N-1,4-PHENYLENE)-C(-CH3)2-((BR)N-1,4-

PHENYLENE)-O-CH2-CH2-O-CH2-

WHEREIN N IS 1 OR 2. THIS POLYFROMAL CAN FORMED INTO A MOLDABLE OR FIBER-FORMING COMPOSITION COMPRISING AN ADMIXTURE OF FROM 50 TO 95 WEIGHT PERCENT POLYESTER AND FROM 50 TO 5 WEIGHT PERCENT OF THE POLYFORMAL. MOLDED OBJECTS OF THE MOLDABLE OR FIBER FORMING COMPOSITION EXHIBIT DESIRABLE FLAME RETARDANCE AS ONE WOULD EXPECT, AND, IN ADDITION, EXHIBIT ADVANTAGEOUS RETENTION OF THE FLAME RETARDANT WITHIN THE POLYMER MATRIX DURING AGING, ADVANTAGEOUS LACK OF DISCOLORATION DURING MOLDING AND ADVANTAGEOUS LACK OF DISCOLORATION UPON EXPOSURE TO ULTRAVIOLET LIGHT. FIBERS OF THE MOLDABLE OR FIBER-FORMING COMPOSITION EXHIBIT DESIRABLE FLAME RETARDANCE AS ONE WOULD EXPECT, AND, IN ADDITION, EXHIBIT ADVANTAGEOUS RETENTION OF FLAME RETARDANCY AFTER DRY CLEANING AND WASHING, ADVANTAGEOUS MECHANICAL PROPERTIES, ADVANTAGEOUS LACK OF DISCLORATION OF THE TEXTILE FIBERS DUING MELT SPINNING, AND ADVANTAGEOUS LACK OF DISCLORATION UPON EXPOSURE TO ULTRAVIOLET LIGHT.

Description

3,809,681 BROMINATED BISPHENOL A DIETHANOL POLYFORMAL Harry R. Musser and Winston J. Jackson, Jr., Kingsport,

Tenn., assignors to Eastman Kodak Company, Rochester N.Y. Nd Drawing. Filed Aug. 16, 1972, Ser. No. 281,259

Int. Cl. C08g 5/10 us. Cl. 260-52 2 Claims ABSTRACT OF THE DISCLOSURE Disclosed is a brominated bisphenol A diethanol polyformal comprised of recurring units of the structure CHI-CH1- -CI-Ig where n is 1 or 2. This polyformal can be formed into a moldable or fiber-forming composition comprising an admixture of from 50 to 95 weight percent polyester and from 50 to 5 weight percent of the polyformal. Molded objects of the moldable or fiber forming composition exhibit desirable flame retardance as one would expect, and, in addition, exhibit advantageous retention of the flame retardant within the polymer matrix during aging, advantageous lack of discoloration during molding and advantageous lackof discoloration upon exposure to ultraviolet light. Fibers of the moldable or fiber-forming composition exhibit desirable flame retardance a one would expect, and, in addition, exhibit advantageous retention of flame retardancy after dry cleaning and washing, advantageous mechanical properties, advantageous lack of discoloration of the textile fibers during melt spinning, and

advantageous lack of discoloration upon exposure to ultraviolet light.

' This invention broadly relates to a polyformal of brominated bisphenol A diethanol and formaldehyde; In a first embodiment, this invention relates to the brominated bisphenol A diethanol polyformal itself. In a second embodiment, this invention relates to a composition formed by admixing the brominated bisphenol A diethanol polyformal with a polyester. In a third embodiment, this invention relates to a textile fiber. of the composition formed by admixing the brominated bisphenol A diethanol polyformal and a polyester.

.The use of textile fibers and molded objects of synthetic polymers has increased tremendously over the last several decades. .The increase in the use of synthetic polymers for preparing synthetic fibers has resulted in large part from the desirable combination of properties that can be achieved in a textile article by using synthetic fibers or blends of natural and synthetic fibers. The increase in the use of molded objects of synthetic polymers has also resulted in large part from the desirable combination of properties exhibited by objects molded of synthetic flbers.

With regard to the desirable properties of a synthetic textile fiber, it is well known in the art that although a synthetic textile fiber may have any number of desirable properties, every textile fiber must have a number of necessary properties to make the fiber commercially acceptable for typical applications such as wearing apparel, carpets and the like. Historically, the necessary properties include United States Patent 0 'ice desirable mechanical properties, lack of discoloration during spinning, and lack of discoloration upon exposure to ultraviolet light.

One undesirable property of most synthetic fibers is a lack of flame retardancy. The growing significance of this property has now caused many textile fibers to be regarded as commercially unsatisfactory for many applications because of the lack of flame retardancy, even though the textile fibers exhibit all the properties historically necessary for commercial acceptance. One particular and significant instance where textile fibers must exhibit flame retardancy is the childrens sleepwear field where blends of polyester and cotton enjoy popularity.

Therefore, to meet current standards for many typical textile applications, including particularly childrens sleepwear, the properties that have been historically necessary for commercially acceptable textile fibers must be revised to include at least a moderate degree of flame retardancy, and in some cases substantial flame retardancy.

Efforts to produce synthetic textile fibers which will meet many of the current standards of flame retardancy and still exhibit other properties necessary for commercial acceptance have generally been unsatisfactory. The failure to produce the desired fiber has not generally resulted from an inability to impart flame retardancy to a fiber, but, instead has resulted from an inability to impart flame retardancy to the fiber and still retain the combination of other properties which have been historically necessary in commercially acceptable fibers. Specifically, it is well known in the art that compounds containing bromine and/ or chlorine of virtually every kind and description, and particularly brominated aromatic compounds, are all etfective in imparting flame retardancy to polyester fibers; however, these compounds often either wash or dry clean out and destroy the flame retardancy of the fiber, or result in one or more of the commercially necessary properties being unsatisfactory. For example, the addition of bromine-containing compounds to polyester fibers often results in unsatisfactory mechanical properties, discoloration of the fibers during melt spinning or discoloration of the fibers upon exposure to ultraviolet light. Also, the bromine-containing compounds often wash or dry clean out to produce a level of flame retardancy substantially the same as a polyester fiber not containing a bromine-containing compound.

Considering now the properties of a molded object of a synthetic polymer, it is Well known in the art that, although a molded object may have any number of desirable properties, every molded object must have a number of necessary properties to make the molded object commercially acceptable for typical applications. Historically, the necessary properties include a lack of discoloration of the molded object during molding, a lack of discoloration of the molded object upon exposure to ultraviolet light and a relatively clean surface due to lack of exudation of material from the molded object on aging at elevated temperatures.

As in the case of fabrics of synthetic polymers, one undesirable property of most objects molded of synthetic polymers is a lack of flame retardancy. The growing significance of this property has caused previously accepted molding compositions to now be regarded as commercially unsatisfactory in many applications because of the lack of flame retardancy of the molded object, even though the molded object exhibits all the properties historically necessary for commercial acceptance.

Therefore, to meet current standards for many typical molding applications the properties that have been historically necessary for commercially acceptable molded objects must be revised to include at least a moderate degree of flame retardancy, and in some cases substantial flame retardancy.

In a manner analogous to synthetic fibers, efforts to produce molding compositions which can be molded into objects which will meet many of the current standards of flame retardancy and still exhibit other properties necessary for commercial acceptance have generally been unsatisfactory. As in the case of synthetic fibers, the failure to produce the desired composition has not generally resulted from an inability to impart flame retardancy to the molded object, but, instead, has resulted from an inability of the molded object to retain the flame retardant within the polymer matrix and also not discolor during molding or upon exposure to ultraviolet light. Specifically, it is well known in the art that compounds containing bromine and/or chlorine of virtually every kind and description, and particularly brominated aromatic compounds, are all effective in imparting flame retardancy to objects molded from a polyester. However, these compounds often exude to the surface of the object. \Also, these compounds often discolor the molded object either during molding or upon exposure of the molded object to ultraviolet light.

In one aspect of our invention we have now discovered a textile fiber that retains a high degree of flame retardancy after dry cleaning and washing, and, in addition, exhibits a combination of other necessary properties to make the fiber commercially acceptable. Thus, we have discovered a textile fiber that exhibits not only the historically necessary properties for commercial acceptability, but is flame retardant as well.

In another aspect of our invention We have now discovered a moldable composition that can be molded into objects that retain the flame retardant within the polymer matrix, does not discolor during molding and does not discolor upon exposure to ultraviolet light. Thus, we have discovered a composition that can be molded into an object that exhibits the historically necessary properties for commercial acceptability, and is flame retardant as well. It is particularly surprising that the molded objects do not discolor upon exposure to ultraviolet light, such as sunlight, since the bromine atoms are attached to an aromatic ring.

An advantage of the textile fibers of this invention is the high degree of flame retardancy after washing and dry cleaning. Another advantage of the textile fibers of this invention is the desirable mechanical properties of the textile fiber. Another advantage of the textile fibers of this invention is the desirable lack of discoloration of the fibers during melt spinning. Still another advantage of the textile fibers of this invention is the desirable lack of discoloration of the fibers upon exposure to ultraviolet light.

An advantage of the molding composition of this invention is the high degree of flame retardancy retained by the molded object due to the flame retardant not exuding to the surface of the object. Another advantage of the molding composition of this invention is the lack of substantial discoloration of the molded object during molding. Yet another advantage of the molding composition of this invention is the lack of discoloration of the molded object upon exposure to ultraviolet light.

Other advantages and features of this invention will be readily apparent to those skilled in the art from the following description and appended claims.

The prior art that applicants are aware of is German 1,252,413, Polish 48,893, German 1,149,899, German 1,001,'819, Japanese 46/3,174, Japanese 46/l0,101, Dutch 7015991, British 1,115,611, British 1,206,171, US. 2,968,- 646, US. 2,568,658, US. 2,287,442, US. 3,234,167, US. 3,234,168, U.'S. 3,294,742, US. 3,334,152, US. 3,367,990, US. 3,395,118 and US. 3,524,901.

Broadly the brominated bisphenol A diethanol polyunits of the structure formal of the first embodiment of this invention can be Br CC CH o-om-cm-bwm where n is 1 or 2. Y

In a preferred aspect n is 2 and both bromine atoms are in'the ortho position with regard to the oxygen atom.

Broadly speaking, the admixture of the brominated bisphenol A diethanol polyformal and polyester of the second embodiment of this'invention can be described .as a moldable or fiber-forming composition comprising an admixture of (1A) based on the weight of the composition, from 50 to 95 weight percent polyester, and

(B) based on the weight of the composition, from 50 to 5 Weight percent of the brominated bisphenol A diethanol polyformal described above.

In a preferred aspect of this embodiment, (A) is from to 92 weight percent and (B) is from 20 to 8 weight percent.

In another preferred aspect of this embodiment th polyester is poly (ethylene terephthalate), poly(tetramethylene terephthalate) or poly(1,4-cyclohexylenedimethylene terephthalate). 'Poly(tetramethylene terephthalate) is an especially preferred polyester.

Broadly speaking, the textile fiber of the third embodiment of this invention can be described as a textile fiber comprised of the composition of the second embodiment described above.

In a preferred aspect of the third embodimena'the polyester is poly(ethylene terephthalate) or poly(1,4-cyclohexylenedimethylene terephthalate), with the poly(ethylene terephthalate) being especially preferred. In this invention the poly(ethylene terephthalate) or the poly(1,4- cyclohexylenedimethylene terephthalate) can contain minor amounts of other materials which alter the properties of the fibers. These materials can be introduced into the polyesters either as a comonomer or a physical blend. Specifically the polyester can be modified with a comonomer that imparts basic dyeability to the fiber.

The usefulness of the polyformal of the first embodiment of this invention is that the polyformal can be admixed with a polyester and useful flame retardant articles, such as molded objects and fibers, can be prepared from the admixture.

The polyformal can be used by admixing the polyformal with the polyester by conventional means such as mixing pellets of each polymer, mixing the molten polymers,'coextrusion, or slurrying a solution of the additive with the polyester powder and evaporating off the solvent. Other conventional means of admixing polymers can 'be used.

The usefulness of the admixture of the polyformal and the polyester of the second embodiment of the invention is that the admixture can be prepared into useful flame retardant articles, such as molded objects and fibers.

The admixture can be used to prepare useful flame retardant articles by techniques well known in the art. For example, the admixture can be melt spun, drawn, heatset and processed into textile fibers according to conventional methods well known in the art. Additionally the admixture can be injection molded into useful molded objects using conventional processes and apparatus.

The brominated bisphenol A diethanol polyformal of this invention can be prepared by a process comprising contacting in a solvent, under polymerization conditions, in the presence of a suitable acid catalyst, formaldehyde and brominated bisphenol A diethanol corresponding to the structure where n is 1 or 2.

The solvent useful in this process can comprise a solvent that is inert with regard to the reactants-Although many conventional solvents can be used, benzene, toluene and hexane are preferred because of their cost and availability.

The pressure used for the polymerization reaction can vary widely. Pressures higher than atmospheric can be used but water removal is, of course, more diflicult at elevated pressures. Pressures lower than atmospheric can be used, but low pressures are to some extent undesirable because low pressures will tend to allow the formaldehyde to escape from the inert solvent. Atmospheric pressure is preferred because of the ease of creation as well as the minimization of undesirable side eflfects.

The temperature used for the polymerization reaction can also vary widely. Temperatures above about 100 C. can be used but are to some extent undesirable because the formaldehyde'will tend to escape from the polymerization solvent. In a preferred embodiment the temperature is about IOU-110 C.-In this embodiment the reaction mixture can be heated at reflux to azeotropically I move the water created by condensation of the forma dehyde and the brominated bisphenol A diethanol.

The acid catalyst of this invention can be a wide variety of catalysts that function as proton donors to catalyze the polymerization reaction. Examples of acids that could be used include, p-toluenesulfonie acid, sulfuric acid, trifluoromethanesulfonic acid, methanedisulfonic acid, camphorsulfonic acid and perchloric acid.

In this invention the formaldehyde can be in various forms such as paraformaldehyde, gaseous formaldehyde .or a dialkyl formal. Paraformaldehyde is preferably used because of its ease inhandling, lack of color-'formingimpurities, and its ability to form high molecular Weight polyfo'rmals. When paraformaldehyde is used the acid catalyst not only functions as a proton donor to catalyze the polymerization reaction, but, in addition, functions to depolymerize the paraformaldehyde.

The contact between the brominated bisphenol A diethanol and formaldehyde can be preferably effected by merely stirring a solution of the formaldehyde and,brominated bisphenol A diethanol in the solventjlf"desired, other contacting procedures well known in the art could be used, such as packed towers, bubble "towersand the like.

After polymerization is complete, isolation of the polyformal can be accomplished bytechniques well known in the art such as removal of the solvent or precipitation in a nonsolvent, such as methanol.

The inherent viscosity of the polyformal is at least 0.05 andpreferably at least 0.15. p

The brominated bisphenol A diethanol that is condensed with formaldehyde can be prepared by condensing one mole of brominated bisphenol A with 2 moles of ethylene oxide to form one mole of brominated bisphenol A diethanol. This reaction is well known in the art and is disclosed in Canadian Pat. 663,542.

The thermal stability of the polyformal may be increased by acetylation of hydroxy end groups, if desired.

Other methods for preparing the polyformal are disclosed in US. Pat. 2,968,646.

The polyester useful in this invention can be derived from aliphatic or alicyclic diols containing 2 to 40 carbon atoms. Examples of such diols include ethylene glycol; diethylene glycol; 1,2-propylene glycol; 2,4-dimethyl-2-ethylhexane-1,3-diol; Z-ethyl 2 butyl-1,3-propanediol; 1,4- butanediol; 1,5-pentanedio1; 1,6-hexanediol; 1,10-decanediol; 1,4-cyclohexanediol; l,4-cyclohexanedimethanol and 2,2,4,4-tetramethyl-1,3-cyclobutanediol. Ethylene glycol, 1,4-butane diol and 1,4-cyclohexanedimethanolare pre ferred diols. Copolyesters may be prepared using two or more of the above diols. Two or more dicarboxylic acids or diols may be used to give copolyesters or block polymers.

The polyesters useful in this invention can be derived from aliphatic, alicyclic, or aromatic dicarboxylic acids having 3 to 40 carbon atoms. Examples of such acids include adipic; azelaic; sebacic; 1,4-cyclohexanedicarboxylic; terephthalic; isophthalic and 1,4-naphthalic. Terephthalic acid is preferred. It will be understood that the corresponding esters of these acids are included in'the term dicarboxylic acid. Copolyesters may be prepared using two ormore of the above dicarboxylic acids or esters thereof.

To reduce the spinning temperature of the admixture of the polyformal and the polyester, a processing aid also may be blended with the polyformal and polyester. 7

The presence of synergists, such as phosphorus and/or antimony, further improves the flame resistance of articles prepared from the admixture of the polyformal and the polyester.

In addition to antimony compounds and brominated additives, the articles prepared from the admixture of the polyformal and the polyester can contain antioxidants, ultraviolet stabilizers, thermal stabilizers, nucleating agents, plasticizers, fillers, glass fibers, pigments, lubricants and other additives.

In one particularly preferred embodiment of the invention the polyformal is blended with poly(tetramethylene terephthalate). In this embodiment, other additives can be added to the poly(tetramethylene terephthalateysuch an antioxidants, pigments, fillers, plasticizers, and reinforcing agents such as glass fibers or asbestos. A composition of about 16 weight percent polyformal, about 5 weight percentantimony trioxide and about 20 weight percent glass fiber gives especially desirable results because objects molded of the composition are quite strong and pass even the most stringent flammability tests.

The following examples are intended to illustrate but not limit the invention.

."Inthis disclosure, the inherent viscosities are determined at 25 C. in 60/40 phenol/tetrachloroethane at a concentration of 0.23 g./ ml. All samples are vacuum dried at -100 C. overnight prior to spinning or molding.

The oxygen index test is described in Modern Plastics, March 1970, p. 124;

1 t EXAMPLE 1 This example describes the preparation of the brominated bisphenol A diethanol polyformal.

In a 1000-ml., three-neck flask fitted with a mechanical stirrer, Dean-Stark trap, and condenser are placed 400 g, (0.633 mole) of tetrabromobisphenol A diethanol and 460 ml. of benzene. The reaction mixture is heated at reflux for 2 hr. during which time the tetrabromobisphenol A diethanol dissolves. The solution temperature is then decreased to 65 C. and 20.6 g. (0.650 mole) of paraformaldehyde and 2.0 g. of p-toluenesulfonic acidare added. After the reaction mixture is allowed to stir at 65 Cyfor 90min, the temperature is increased to reflux and the-water (11.4 ml., 0.633 mole) is azeotropically removed. This requires approximately 3 /2 hr. After the mixture is cooled to room temperature, 0.5 ml. of 15 M ammonium hydroxide is added with vigorous stirring to neutralize the catalyst. The slightly viscous benzene solu tion is then coagulated by slow addition to 8 liters of methanol. The resultant white powder is washed with 500 ml. of methanol and dried overnight at 50 C. under a nitrogen sweep and a vacuum of 17 in. of mercury. The polymer has an inherent viscosity of 0.12 and a softening point of 80 C.

To 350 g. of the polyformal dissolved in 500 ml. of benzene is added 50 ml. of acetic anhydride. The solution 270 Clto wef'white fibers. The'fibers are'drawn in water at 1C. and thn in superheated steam for an overall draw factdfoffLQi After being heat set ima rel'axed'state t'1 15 CZ, the "fibers have the following prop den/11.; 3.f6 g/de'n. tenacity, 33% elongation} 44 gQ /deingela "modulus, and'a 234 :C; llowpoint at 2"g."/den. loadl'A tube knittedjf-r om" these fibers shows no yellowing after40' hr. exposure in a' carbon-arc Fade-'- Orneter. The-knit fiber also passes the Childrens-Sleep- Wear Test "(FR DOC 71*1'0837). The fibers in the knitted sample show- 'no' loss in'bron'n'ne content after l0l'a1indr'y cycles in accordance with AATCC Test Method 61-1969, Another sampleshows no loss in' broin'ine c6ntei1t"after"1'5 dry cleaning cycles "in' accordance'with AATCC Test Method 132-1969. The knitted samples dy'e well and exhibit desirable light fastn'ess.

EXAMPLE 3 erties: 2.5

DLTDP-.The polyester containing the antioxidants is then dry'ble'nded with 15% tetrabromobisphenol-rA diethanol polyformal' (inherent viscosity 0.15) and 2.5 antimony ox'ideuThe blend is extruded at'280 C. with a Brabender Plasticorder extruder. The resultant white pellets are then injection molded at 280 C. to give 1/8- x 1/2- x -in.

bars. The bars have an oxygen index of 27 as compared to 21 for the control poly(tetramethylene terephthalate) Thebromine content ofi the bars does not decrease during agingfor 1 mo. in an oven at 155 C. The ba'rs exhibit no discoloration during molding or during. exposure to ultraviolet light in a carbon-arc Fade-Ometeffor .40 hr;

I EXAMPLE 4 1 This example describes the preparatiohbf fiber of an admixture of'a polyester and the brominated .bisphenol A diethanol polyformal. 1 Polyt1,4-eyclohexylenedimethylene terephthalat e) hav: ing .an inherent viscosity of 0.86 is dry blended with tetrabromobisphenol A diethanol. polyformal .(inher'ent viscosity 0.12) to give a mixture containing,.1.0% by weight of polyformal. The blend is spun at 290 C. to give white fibers. The fibers are/drawn in water at 68 C. and-then in superheated steam for an overalllidraw factor of 3.8. After being heatset in a'relaxed state at 175 C. for 5 min; the fibers have the following properties: 3.2 den./fil., 2.7 g./den. tenacity, 21% elongation, 33 g':-/de'n. elastic mod'ulu's, and a '260--'-C.--fiow pointat 0:2 g./den."load. The" fibers exhibit improved resistance to burning, I resistance to yellowing "during"40:"hr. inua carhon arc Fade-Ometer,l and no significant loss of b'romine during dry cleaning treatments. 1 1' 'E M E Thisfexampleg:describes the preparation of; fibers of an admixture of-aupolyester and the brominated bisphenol A dietha-nol-polyformal; y I an? 1 -A*blend of the-' poly (ethylene .terephthalate) used in Example Za-and tetrabromobisphenol: A diethanol polyfor'mal .is "meltspun .at 260 :C.-'-into nondiscolored fibers. The drafted, heat setzfiberzs hayeihe following properties: 2.4 -den./fil.-,- 3.4 g./den. tenacity,,,21%-.elongation, 42 g./den..elast-ic moduls, .2409, C. fiow point at 0.2 .g./ demxload. :Thefibers show further improved-resistance to burningfcompared, t0'5 the fiberszin 'Example 2, no yellowing {during .40 hr. in; a carbonarc Fade-Ometer, and no significant loss of bromine during 15 dry'cleaning trleaflfients. iAlthough the invention has beenHdescribedin considerable.- detail with particular referenceytocertainprew ferred embodiments thereof, variations and modifications may-beeffectedwithin-the spirit and scope; of the inventionz;

.We' claim: 1 I '1. A .polymeriecomposition having aninherent viscosity of at least 0.05 comprisedv ofi-recurring unitsqofi the where r'iisl o r L 2. The compos on .or "claim ,1 wherein his 2 and both brom ne atoms are in the, ortho positionwith' regard fl at qm 3 References Cited I k UNITED STATES .PATE'NT'S? Y J 12/ 1963* 'Von Brachel WILLIAM H. SHOR'ITIPrimaryExaminer i P RT I L A esam a ii