GB1584743A

GB1584743A - Copolycarbonate resin

Info

Publication number: GB1584743A
Application number: GB2048177A
Authority: GB
Original assignee: Mobay Corp
Current assignee: Bayer Corp
Priority date: 1976-05-18
Filing date: 1977-05-16
Publication date: 1981-02-18
Also published as: CA1094738A; DE2721595A1; FR2352016A1; JPS52140596A

Description

(54) COPOLYCARBONATE RESIN (71) We, MOBAY CHEMICAL CORPORATION, a corporation organised under the laws of the State of Pennsylvania, U.S.A. of Penn Lincoln, Parkway West, Pittsburgh, Pennsylvania 15 205, U.S.A., do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:- According to US-PS 3,250,744 and DT-AS 1,187,797 polycarbonates from at least 20 mole percent aromatic diphenol thioether, based on the total diphenol content, are known.

The improvement offered by the polycarbonates of the present invention over the polycarbonates of US-3,250,744 is the improved critical thickness of the former as compared with conventional bisphenol - A - polycarbonates which is obtained by the incorporation of small amounts of aromatic diphenol thioethers. This results in a better economic basis of the polycarbonates of the present invention over those of US-3,250,744.

Moreover, the polycarbonates of the present invention have an improved melt index compared with those of US-3,250,744.

The polycarbonates of the present invention have improved critical thickness but are otherwise closely related to the conventional ones with respect to their other properties and consequently their technology.

According to the invention a copolycarbonate resin having improved critical thickness is provided which has a melt flow of 1 to 24 gram/l0 min. at 3000C (ASTM 1238) and eontains from 2 up to 15 mole percent of the repeating structural unit

wherein R, and R2 are hydrogen or lower alkyl groups having 1 to 4 carbon atoms and n equals 0 to 2, and from 85 to 98 mole percent of the repeating structural unit

wherein X is hydrogen, a Ct to C4 alkyl radical or a halogen, preferably Br or Cl, most preferably wherein X is hydrogen or a C1-C4 alkyl radical; and n, equals 1 or 2 and Z is a single bond, an alkylene or alkylidene radical with 1 to 7 carbon atoms, preferably methylene or isopropylidene. When n,=2 and R, and R2 are hydrogen, X is not Cl to C3 alkyl, chlorine or bromine.

When used herein "copolycarbonate resin" means the "neat" resin i.e.

without additives; "polycarbonate" means the copolycarbonate resin with additives therein.

The copolycarbonate resins of the invention may be prepared by conventional methods for polycarbonate resins, and may have a weight average molecular weight of 10,000 to 200,000. They have a melt flow rate of I to 24 gram/l0 min at 300"C (ASTM 1238).

Any suitable processes, reactants, catalysts, solvents, and conditions for the production of the polycarbonate resins of this invention which are customarily employed in polycarbonate resin syntheses may be used such as disclosed in German Patent Nos. 1,046,311 and 962,274; U.S. Patents 3,028,365, 2,999,846, 3,248,414, 3,153,008, 3,215,668, 3,187,065, 2,964,794, 2,970,131, 2,991,273, and 2,999,835 all incorporated herein by reference. The preferred process is the interfacial polycondensation process.

According to the interfacial polycondensation process, certain of the above copolycarbonate resins are obtained by reacting the bisphenols represented by the structural formulae:

wherein X is hydrogen, a C, to C4 alkyl radical, or a halogen; preferably Br or Cl, most preferably wherein X is hydrogen or a C1-C4 alkyl radical; and n, equals 1 or 2 and wherein Z is a single bond, an alkylene or alkylidene radical with I to 7 carbon atoms, preferably methylene or isopropylidene and

wherein R, and R2 are hydrogen or lower alkyl groups having I to 4 carbon atoms, and n is0, 1 or 2, at a temperature of -20" to + 150 C with an alkaline earth metal oxide or hydroxide or alkali metal hydroxide to form the alkaline earth metal or alkali metal salt of the bisphenols. The salt mixture is present in an aqueous solution or suspension and is reacted with phosgene, carbonyl bromide, or bischloroformic esters of the diphenols. An organic solvent is provided in the reaction admixture which is of a solvent for the polymer but not for the phenolic salts hereinbefore described. Thus, chlorinated aliphatic hydrocarbons or chlorinated aromatic hydrocarbons maybe used as~ the organic solvent which dissolves the condensation product.

In order to limit the molecular weight one may use monofunctional reactants such as monophenols, for example the propyl-, isopropyl- and butyl-phenols, especially p-tert.-butyl-phenol and phenol itself. In order to accelerate the reaction, catalysts such as tertiary amines, quaternary ammonium, phosphonium or arsonium salts may be used. The reaction temperature should be 200 to +150"C., preferably 0 C to 1000C.

According to the polycondensation process in a homogeneous phase, the dissolved reaction components are polycondensed in an inert solvent in the presence of an equivalent amount of a tertiary amine base required for absorption of the generated HCI, such as e.g. N,N - dimethylaniline, N,N - dimethyl cyclohexylamine or preferably pyridine. In still another process, a diaryl carbonate can be transesterified with the aromatic dihydroxy compounds to form the polycarbonate resin.

It is to be understood that it is possible to combine in the processes described above in a chemically meaningful way both the aromatic dihydroxy compounds, and the monohydroxy compounds in the form of the alkali metal salts and/or bishaloformic acid esters, and the amount of phosgene or carbonyl bromide then still required in order to obtain high-molecular weight products. Other methods of synthesis in forming the polycarbonates of the invention such as disclosed in U.S.

Patent 3,912,688, incorporated herein by reference, may be used.

The two diphenols necessary for synthesizing the repeating structural units (I) and (II) are a thiodiphenol, preferably 4,4'-thiodiphenol, and a bisphenol, preferably having either methylene or isopropylidine linking the two phenol rings.

The most preferred bisphenol is 2,2 - bis - (4 - hydroxyphenyl) - propane; other bisphenols such as bis -(4 - hydroxyphenyl)- methane, and 2,2 - bis -(4 - hydroxy - 3,5 - dimethylphenyl)propane may be utilized.

In addition to the 4,4'-thiodiphenol and the bisphenols recited above other di (monohydroxyaryl) - alkanes may be incorporated in the polymer at low levels (i.e.

levels which do not affect critical thickness values). Exemplary dihydroxy compounds are taught by U.S. Patent 3,028,365 incorporated herein by reference.

As low as 2 mole percent of the thiodiphenol based on the total diphenol shows improved critical thidkness values over a conventional bisphenol- A polycarbonate while 10 mole percent of the thiodiphenol raises the critical thickness value of the polycarbonate to levels equivalent to those blends of bisphenol A polycarbonate with a polyolefin polymer. However, the thiodiphenol based polycarbonate maintains transparency, good colorant dispersability and other properties substantially improved over the polycarbonate polyolefin blend.

The invention will be further described by illustration in the following examples.

Example I A copolycarbonate resin was prepared by reacting a mixture of the disodium salts of 2,2 - bis - (4 - hydroxyphenyl) - propane (bisphenol A) and 4,4'thiodiphenol with phosgene in accordance with the interfacial polycondensation synthesis hereinbefore discussed. The ratio of bisphenol A to 4,4'-thiodiphenol was 9 to 1. The copolycarbonate was tested for physical, mechanical, and optical properties with the test results reported in Table I. The copolycarbonate was found to be highly transparent. Also Table II shows the effect of oven aging at 1050C on impact and critical thickness properties.

Example II Example I was repeated except the mole ratio of 4,4'-thiodiphenol: bisphenol A was 2:98. The copolycarbonate resin was found to be highly transparent. Test results of Example II and the following Examples are reported in Tables I and II.

Example III (Comparative) Example II was repeated except the mole ratio of 4,4'-thiodiphenol: bisphenol A was 20:80. The copolycarbonate resin was found to be highly transparent.

Example IV (Comparative) Example IV is a bisphenol A polycarbonate resin having no 4,4'-thiodiphenol therein.

TABLE I Examples I II III IV Mole%BPA1 90 98 80 100 (Comparison) (Control) Monomers TDP2 10 2 20 Izod3 (Notched) Impact (Ft. Ibs/in) 1/8" 14.89 16.0 14.59 18.44 1/4" 14.96 7.98 14.75 3.20 Critical Thickness mils 255 247 > 255 225 Relative Viscosity4 1.340 1.318 1.377 1.355 Melt Index g/10 min 2.9 3.6 2.5 3. 1 Heat Distortions Temp. "C 135 134 133 134 O/,s found (calc.) 1.12(1.32) 0.24(0.30) 2.42(2.63) Oxygens Index 25.4 25.4 25.4 25.5 V0 Brightness 87.49 86.83 87.06 86.30 % Haze7 3.2 - 1.5 - Tensile Strength psi 9000 9800 8900 9800 Ultimate Tensile 9400 10000 9000 10100 Strength psi V0 Elongation 8 - 10 8 % Elongation Failure 90 > 100 95 105 'BPA is Bisphenol A 2TDP is 4,4'-thiodiphenol 3ASTM D256 40.5 g. resin/100 ml. methylene chloride at 250C 50C under 264 psi load (ASTMD-648) 6ASTM D2863 7ASTM D-1003.

As is shown in the data presented in Table I as low as 2 mole% of 4,4' thiodiphenol based upon the total diphenol content in the polycarbonate resin improves the critical thickness of articles molded therefrom while maintaining substantially equivalent physical and mechanical properties of the conventional bisphenol A polycarbonate resin.

Also after aging in air the 1/8" notched impact strength remains almost unchanged, whereas the critical thickness decreases slightly.

While it has been known to synthesize polycarbonates from sulfur containing diphenols such as 4,4'-sulfonyl diphenol to incorporate the repeating structural unit

into the polymer such structural units do not improve the critical thickness values of polycarbonates based partially on 4,4'-sulfonyl-diphenol. Table II shows critical thickness values contrasting 4,4'-sulfonyl-diphenol based polycarbonates with the 4,4'-thiodiphenol based polycarbonates.

TABLE II Monomer Compositions Critical thickness Melt Flow (mole V) mils (g/10 min.) *BPA' SDP2 225 6.2 (90) (10) BPA TDP3 255 2.9 (90) (10) Random Copolymer BPA (100) Control 225 3.0 'Bisphenol A 24,4'-Sulfonyldiphenol 34,4'-Thiodiphenol *The BPA (90)-SDP(10) copolycarbonate was found to have the following additional properties: Heat Distortion Temp. at 264 psi, 0C 147 Impact ft. Ibs/in (1/8") 14.80 Impact ft. Ibs/in (1/4") 3.65 Tensile strength, psi 9300 Ultimate Tensile Strength, psi 9100 Elongation yield V 10 Ultimate Elongation V 95 WHAT WE CLAIM IS:- 1. A copolycarbonate resin having a melt flow of 1 to 24 gram/l0 min. at 3000C (ASTM 1238) and comprising: from 2 to 15 mole percent of sulfur-containing structural units of the general formula

wherein R, and R2 are hydrogen or lower alkyl groups having 1 to 4 carbon atoms and n is 0, 1 or 2, and from 85 to 98 mole percent of structural units of the general formula

wherein X is hydrogen, a C, to C4 alkyl radical or a halogen atom, n, equals I or 2, and Z is a single bond, an alkylene or alkylidene radical with I to 7 carbon atoms, with the proviso that when n,=2 and R, and R2 are hydrogen, X is not C, to C3 alkyl, chlorine or bromine.

2. A copolycarbonate resin according to claim 1 wherein Z is a methylene or isopropylidene radical.

3. A copolycarbonate resin according to claim 1 or 2 wherein X is hydrogen, a C1-C4 alkyl radical, Br or Cl.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **.

TABLE II Monomer Compositions Critical thickness Melt Flow (mole V) mils (g/10 min.) *BPA' SDP2 225 6.2 (90) (10) BPA TDP3 255 2.9 (90) (10) Random Copolymer BPA (100) Control 225 3.0 'Bisphenol A 24,4'-Sulfonyldiphenol 34,4'-Thiodiphenol *The BPA (90)-SDP(10) copolycarbonate was found to have the following additional properties: Heat Distortion Temp. at 264 psi, 0C 147 Impact ft. Ibs/in (1/8") 14.80 Impact ft. Ibs/in (1/4") 3.65 Tensile strength, psi 9300 Ultimate Tensile Strength, psi 9100 Elongation yield V 10 Ultimate Elongation V 95 WHAT WE CLAIM IS:- 1. A copolycarbonate resin having a melt flow of 1 to 24 gram/l0 min. at 3000C (ASTM 1238) and comprising: from 2 to 15 mole percent of sulfur-containing structural units of the general formula

wherein R, and R2 are hydrogen or lower alkyl groups having 1 to 4 carbon atoms and n is 0, 1 or 2, and from 85 to 98 mole percent of structural units of the general formula

wherein X is hydrogen, a C, to C4 alkyl radical or a halogen atom, n, equals I or 2, and Z is a single bond, an alkylene or alkylidene radical with I to 7 carbon atoms, with the proviso that when n,=2 and R, and R2 are hydrogen, X is not C, to C3 alkyl, chlorine or bromine.
2. A copolycarbonate resin according to claim 1 wherein Z is a methylene or isopropylidene radical.
3. A copolycarbonate resin according to claim 1 or 2 wherein X is hydrogen, a C1-C4 alkyl radical, Br or Cl.
4. A copolycarbonate resin according to any one of claims I to 3 wherein the

sulfur containing structural unit is:
5. A copolycarbonate resin according to claim 2 substantially as hereinbefore described in Example I or II.
6. A process for preparing a copolycarbonate having a melt flow of I to 24 gram/l0 min. at 3000C (ASTM 1238), comprising, reacting at a temperature of -200C to +1500C, a. a thiodiphenol of the structural formula

wherein R, and R2 are hydrogen or lower alkyl groups having 1 to 4 carbon atoms, and n is 0, 1 or 2, and b. a compound of the structural formula

wherein X is hydrogen, a C, to C4 alkyl group, or a halogen and n1 is 1 or 2 and Z is a single bond, an alkylene or alkylidene radical with 1 to 7 carbon atoms, with a carbonic acid derivative selected from phosgene, carbonyl bromide, the bischloroformic esters of (a) and/or (b) and diaryl carbonates, wherein (a) is present in the reaction mixture at from 2 to 15 mole percent and (b) is present at from 85 to 98 mole percent based on the total moles of both (a) and (b), and wherein, when n1=2 and R, and R2 are hydrogen, X is not C1 to C3 alkyl, chlorine or bromine.
7. A process according to claim 6 wherein the thiodiphenol (a) is 4,4'thiodiphenol.
8. A process according to claim 6 or 7 wherein Z is methylene or isopropylidene.
9. A process according to any one of claims 6 to 7 wherein (b) is bisphenol A.
10. A process according to claim 6 substantially as hereinbefore described in Example I or
II.