Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G64/00—Macromolecular compounds obtained by reactions forming a carbonic ester link in the main chain of the macromolecule
  • C08G64/04—Aromatic polycarbonates
  • C08G64/06—Aromatic polycarbonates not containing aliphatic unsaturation
  • C08G64/08—Aromatic polycarbonates not containing aliphatic unsaturation containing atoms other than carbon, hydrogen or oxygen
  • C08G64/081—Aromatic polycarbonates not containing aliphatic unsaturation containing atoms other than carbon, hydrogen or oxygen containing sulfur
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L69/00—Compositions of polycarbonates; Compositions of derivatives of polycarbonates

Definitions

• This invention relates to thermoplastic, amorphous, halogen-free aromatic, high molecular weight polycarbonate compositions having improved flame retardance.
• halogen-containing, flame retardant additives can be employed to render plastic products self-extinguishing or flame retardant.
• Such flame retardant additives are typically employed in amounts sufficient to be effective for their intended purpose; generally, on the order of about 5-20% by weight based upon the weight of the plastic composition.
• use of these flame retardants in such amounts can have a degrading affect upon the plastic compositions to be rendered flame retardant often resulting in the deterioration of valuable physical properties of the base polymer. This is particularly so when known flame retardant additives are employed with polycarbonate resins since many of these additives have a degrading affect upon the base polymer typically resulting in discoloration and a loss of impact strength.
• flame retardant polycarbonate compositions which are obtained as blends of a polycarbonate - TDP copolymer and a halogen-containing compound.
• the compositions can optionally include small amounts of a sulfonic or car boxylic acid salt which are preferably perfluorinated.
• sulfur-containing polycarbonate compositions are also known such as crystalline copolycarbonates obtained as the reaction of polycarbonate and TDP as disclosed in "Polycarbonates and Mixed Polycarbonates based on Bis (4-hydroxyphenyl)sulfide” , O.V. Smirnova, G.S. Kolesnikov, A.X. Mikitaeo and T.G. Krichevskaya (Mosk. Khim-Teckhnol. Inst. im Mendeleeva, Moscow) , Vysokomol Soldin, Ser. 4 10(1), 96 101 (1968) (Russ), also reported in "Chem. Abstracts:, 68, 1968.
• U.S. Patent 3,398,212 discloses copolymers and blends of copolycarbonates and copolyesters prepared from halogenated or non-halogenated polycyclic bisphenols and TDP.
• the sulfur-containing aromatic polycarbonates can be present as copolycarbonates derived from mixtures of non-polycyclic, sulfur-free and sulfur-containing diphenols or as blends of conventional polycarbonates and sulfur-containing polycarbonates .
• the term "conventional” as used throughout this application is intended to encompass and should be understood as encompassing polycarbonates derived from diphenols that are non-polycyclic and that are free of sulfur and halogen substituents in their molecular structure.
• the flame retardant polycarbonate compositions of the invention comprise the sulfur-free and sulfur-containing diphenols either as a chemical mixture or a physical mixture, or both.
• the sulfur-free polycarbonate and the sulfur-containing polycarbonate are linked together by chemical bonds, such as in copolycarbonates.
• copolycarbonates of two, or more, components can be coreacted to form alternating or random or block copolycarbonates as well as chemical mixtures thereof.
• a and B for the two diphenol-derived moieties, an alternating copolycarbonate structure would be as follows : while a random copolycarbonate would have the structure:
• non-polycyclic, sulfur-free polycarbonate and the sulfur containing polycarbonate can also be present as a physical mixture or blend, of two or more components wherein no chemical interaction occurs and, thus, no chemical bonds are present linking the components together.
• a physical mixture of the two polycarbonates in its simplest form, would be as shown below:
• wherin m and n have the same value as above, or as physical mixtures of IVa with I and/or II and/or III, or as physical mixtures of IVb with I and/or II and/or III, or as physical mixtures of I and II, or I and III, or II and III.
• polycarbonate composition can comprise both chemical and physical mixtures.
• the conven tional non-polycyclic aromatic polycarbonates that can be employed are homopolymers and copolymers that can be prepared by reacting a halogen-free and sulfur-free diphenol with a carbonate precursor.
• Typical of some of the diphenols that can be employed are 2,2-bis (4-hydroxyphenyl)propane, (also known as bisphenol-A or BPA) , bis (4-hydroxyphenyl)methane, 2,2-bis (4-hydroxy-3-methylphenyl) propane, 4,4-bis (4-hydroxyphenyl)heptane, 1,1-bis (4-hydroxyphenyl) ethane, 1,1-bis (4-hydroxyphenyl)cyclohexane, 1,1-bis (4-hydroxyphenyl) propane, 3, 3-bis (4-hydroxyphenylJpentane.
• Other diphenols of the bisphenol type are also available such as are disclosed in U.S.
• Patents 2,999,835; 3,028,365; and 3,334,154 incorporated herein by reference.
• each X can independently be selected from the group consisting of H or C1 - C 5 alkyl, and W can be a chemical bond, C 1 - C 8 alkylene, C 2 - C 8 alkylidene, C5 - C 12 cycloalkylene or cycloalkylidene.
• the sulfur-containing diphenols from which the sulfur-containing polycarbonates can be obtained can be represented by the following structural formula:
• R and R 1 can each independently be H or C 1 to C. alkyl, and n is 1 or 2.
• Typical of some of these sulfur-containing diphenols are 4 ,4' -thiodiphenol; 2-methyl-4 , 4'-thiodiphenol; 2 ,2' -dimethyl- 4 ,4'-thiodiphenol, 2,2'-di-tertiary-butyl-4 ,4'-thiodiphenol, and the like, all of which are collectively referred to as "thiodiphenol” or "TDP" .
• Such thiodiphenols can be prepared by known meth ods such as that disclosed in U.S. Patent 3,931,335 incorporated herein by reference.
• the carbonate precursor can be either a carbonyl halide , a carbonate ester or a haloformate.
• the carbonyl halid ⁇ s which can be employed are carbonyl bromide, carbonyl chloride and mixtures thereof.
• Typical of the carbonate esters which can be employed are diphenyl carbonate, di- (halophenyl) carbonates such as di- (chlorophenyl) carbonate, di- (bromophenyl) carbonate, di- (trichlorophenyl) carbonate, di- (tribromophenyl) carbonate, etc., di- (alkylphenyl) carbonates such as di(tolyl) carbonate, etc., di-(naphthyl) carbonate, di- (chloronaphthyl)carbonate, phenyl tolyl carbonate, chlorophenyl chloronaphthyl carbonate, etc., or mixtures thereof.
• haloformates which can be used include bis-haloformates of the diphenols employed, including both the sulfur-free and sulfur-containing bisphenols , such as BPA-bis (chloroformate) and thiodiphenol bis-(chloroformate) and their congeners. While other carbonate precursors will occur to those skilled in the art, carbonyl chloride, also known as phosgene, is preferred.
• the aromatic carbonate polymers of this invention can be piepared by employing a molecular weight regulator, an acid acceptor and a catalyst.
• the molecular weight regulators which can be employed include monohydric phenols such as phenol , chroman-I , para tertiarybutylphenol, parabromophenol, and the like.
• phenol is employed as. the molecular weight regulator.
• the acid acceptor can be either an organic or an inorganic acid acceptor.
• a suitable organic acid acceptor is a tertiary amine and includes such materials as pyridine, triethylamine, dimethylaniline, tributylamine, etc.
• the inorganic acid acceptor can be one which can be either a hydroxide, a carbonate, a bicarbonate, or a phosphate of an alkali or alkaline earth metal.
• the catalysts which can be employed are any of the catalysts that aid the polymerization of the diphenol such as bisphenol-A with phosgene.
• Suitable catalysts include tertiary amines such as for example, triethylamine, tripropylamine , N,N-dimethylaniline, quaternary ammonium compounds such as, for example, tetraethylammonium bromide, cetyl triethylammonium bromide, tetra-n-heptylammonium iodide, tetra-n-propylammonium bromide, tetramethylammonium chloride, tetramethylammonium hydroxide, tetra-n-butylammonium iodide, benzyltrimethylammonium chloride and quaternary phosponium compounds such as , for example, n-butyltriphenyl phosphonium bromide and methyltriphen
• branched polycarbonates wherein a polyfunctional aromatic compound is reacted with the diphenol and carbonate precursor to provide a thermoplastic randomly branched polycarbonate.
• the polyfunctional aromatic compounds contain at least three functional groups which are carboxyl, carboxylic anhydride, haloformyl or mixtures thereof.
• the polyfunctional aromatic compounds include trimellitic anhydride, trimellitic acid, trimel lityl trichloride, 4-chloroformyl phthalic anhydride, pyromellitic acid, pyromellitic dianhydride, mellitic acid, mellitic anhydride, trimesic acid, benzophenonetetracarboxylic acid, benzophenonetetra carboxylic anhydride, and the like.
• the preferred polyfunctional aromatic compounds are trimellitic anhydride or trimellitic acid or their haloformyl derivatives.
• blends of a linear polycarbonate and a branched polycarbonate are also included herein.
• the sulfur content thereof should be about 3 - 13 , preferably about 5 - 10 , weight percent based upon the total weight of the final composition. This amount of sulfur is equivalent to a thiodiphenol content of about 23 - 98 mole percent in the broad range and about 35 - 75 mole percent in the preferred range.
• the polycarbonate compositions of the invention exhibit not only excellent flame retardant characteristics , but also exhibit hitherto unknown, felicitious combinations of outstanding proper ties such as impact strength, especially in thicker sections, and better thermal stability. Therefore, there are included in the test results shown hereinafter not only flame retardancy, but notched Izod impact and thermal gravimetric analyses as well. PREFERRED EMBODIMENT OF THE INVENTION
• the following examples are presented to more fully and clearly illustrate the invention. Although the examples set forth the best mode presently known to practice the invention, they are intended to be and should be considered as being illustrative of, rather than limiting, the invention. In the examples, all parts and percentages are by weight unless otherwise specified.
• EXAMPLE 1 Into a mixture of 2283 grams of pure 4 , 4' -isopropylidenediphenol (BPA) (mp 156-157°C; 10.0 mole grams), 5700 grams water, 9275 grams methylene chloride, 32.0 grams phenol and 10.0 grams triethylamine were introduced, at ambient temperature, 1180 grams phosgene over a period of 97 minutes while maintaining the pH of the two-phase system at about 11; i.e., pH 10-12.5, by simultaneously adding a 25% aqueous sodium hydroxide solution. At the end of the addition period, the pH of the aqueous phase was 11.7 and the BPA content of this phase was less than 1 part per million (ppm) as determined by ultraviolet analysis .
• BPA 4' -isopropylidenediphenol
• the methylene chloride phase was separated from the aqueous phase, washed with an excess of dilute (0.01 N) aqueous HCl and then washed three times with deionized water.
• the polymer was precipiated by steam and dried at 95°C.
• the resultant, pure BPA-polycarbonate, which had an intrinsic viscosity (IV) in methylene chloride at 25°C of 0.465 dl/g. was fed to an extruder, which extruder was operated at about 550°F, and the extrudate was comminuted into pellets .
• the pellets were then injection molded at about 600°F into test bars of about 5 in. by 1/2 in. by about 1/8 in.
• V-O Average flaming and/or glowing after removal of the igniting flame shall not exceed 5 seconds and none of the specimens shall drip flaming particles which ignite absorbent cotton.
• V-I Average flaming and/or glowing after removal of the igniting flame shall not exceed 25 seconds and the glowing does not travel vertically for more than 1/8" of the specimen after flaming ceases and glowing is incapable of igniting absorbent cotton.
• V-II Average flaming and/or glowing after removal of the igniting flame shall not exceed 25 seconds and the specimens drip flaming particles which ignite absorbent cotton.
• a test bar which continues to burn for more than 25 seconds after removal of the igniting flame is classified, not by UL-94, but by the standards of the invention, as "burns".
• UL-94 requires that all test bars in each test group must meet the V-type rating to achieve the particular classification; otherwise, the 5 bars r ⁇ c ⁇ ive the rating of the worst single bar. For example, if one bar is classified as V-II and the other four (4) are class ified as V-O, then the rating for all bars is V-II.
• Example 2 The procedure of Example 1 was exactly repeated, except that half of the BPA (1141.5g) was replaced with 1091.5g of 4, 4' -thiodiphenol (TDP) (5 moles; i.e., 50 mole % TDP, or about 6.6 wt. % sulfur) and only 19.8g of phenol was employed.
• TDP 4' -thiodiphenol
• Example 1 The procedure of Example 1 was exactly repeated, except that a mixture of 570.7g (2.5 mole) of BPA and 1637.1g of TDP (7.5 moles; i.e., 75 mole % TDP, or 9.8 wt. % sulfur) was used and only 16.9g of phenol was employed.
• Example 7 The procedure of Example 2 was repeated except that 1482g of 4,4 '-cyclohexlidenebis (2-methylphenol) was employed in place of BPA. The copolycarbonate obtained was found to be V-O pursuant to UL-94. EXAMPLE 7
• Example 1 A physical mixture consisting of 2560g of the polycarbonate of Example 1 and 2440g of a polycarbonate prepar ⁇ d from TDP and phosgene following the procedure of Example 1 was fed to an extruder operating at about 550°F and the pellets obtained therefrom were molded into test samples as described in Example 1.
• EXAMPLE 8 Following the procedure of Example 7, additional test bars were obtained from a physical mixture consisting of 128g of the polycarbonate of Example 1 and 2318g of a TDP-polycarbonate. The clear, colorless test bars had a sulfur content of 12.4 wt. % and were found to be V-O per UL-94.

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• 1981
  • 1981-08-10 JP JP56502710A patent/JPS57501185A/ja active Pending
  • 1981-08-10 WO PCT/US1981/001065 patent/WO1982000468A1/en not_active Ceased
  • 1981-08-10 EP EP19810902225 patent/EP0057214A4/en not_active Withdrawn

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