CA1238164A - Polycarbonate formulations having improved fire characteristics - Google Patents

Abstract

Polycarbonate formulations having improved fire characteristics Abstract of the Invention This invention relates to plates having a thickness of from 1 to 10 mm, and consisting of mixtures of aromatic polycarbonates (mainly based on bisphenol A) and polyesters having butylene tere-phthalate, ethylene terephthalate, and/or cyclo-hexanedimethanol terephthalate units, preferably polybutylene terephthalate units, which have improved fire characteristics according to DIN
4102. This invention relates also to hollow-chamber plates having a thickness of 8 to 16 mm consisting of the same mixtures of materials.

Description

Lo 1 Polycarbonate formulations having improved fire characteristics This invention relates to plates having a thickness of from 1 to 10 mm, consisting of mixtures of aromatic polycarbonate (mainly based on bisphenol A) and polyesters having battalion terephthalate, ethylene terephthalat~ and/or cyclohexanedimethanol terephthalate units, preferably polybutylene terephthalate units, which have improved fire characteristics according to the DIN 4102 test.
Polycarbonates based on bisphenol A have excellent physical properties, like for example transparency, impact strength, high dimensional stability under heat, considerably reduced inflammability, and good processibility from the melt, e.g. by injection mounding and extrusion.
Solid bisphenol-A-polycarbonate plates, hosing a thickness of from 1 to 10 mm, which are produced by extrusion, are used e.g. for wall-paneiling, roofing material, dome lights, paneling for balconies and protective lagging in schools, nursery schools and sports halls.
Extruded hollow sections consisting of bus-phenol A polycarbonate similarly have many fields of application.
~ouldings consisting of bisphenol A polyp carbonate do not inflame easily, and even without specific flame resistant additives they have been given classification V2 in accordance with Underwriters' Laboratories Subject 94.
With flame-resistant or halogen additives or anti dripping substances they are-given classification VOW in accordance with US Subject 94.
The DIN ~102 Standard which is binding in the Federal Republic of Germany classifies building;
''I
lo A 22 232-us : . -16~

- 2 -materials according to their behavior in fire as follows:
building material class A non-combustible building material class By inflames with difficulty building material class By normal inflammability building material class By inflames easily Inflammable building materials are classified By if they pass the test in the fire tunnel; only such building materials are permitted.
Plates and sections of bisphenol A polycarbonate having a thickness of from 1 mm to 6 mm pass the fire tunnel test if they have recently been produced, but fail to do so after out-side exposure for only several months, and so do not comply with the requirements according to DIN blue.
Even with special additives, polycarbonate formula-lions, which are designated as being particularly flame-resistant, fail the fire tunnel test either immediately or after a relative-lye short period of outside exposure. They do not comply with DIN
blue.
This invention provides hollow-chambered fire nests-lent plates having a thickness of 16 mm, consisting of from 99 to 95 % by weight of a high molecular weight aromatic polycarbon-ate based on from I to 100 molt of bisphenol A and from 20 to 0 mow % of 2,2-bis-(3,5-dimethyl-4-hydroxyphenyl)-propane and/or 1,1-bis-(4-hydroxyphenyl)-cyclohexane, and from 1 to 5% by weight of an aromaticaliphatic, thermoplastic polyester, the acid come ye A 22 232 1238~6~L 23189-5719 potent thereof consisting of at least I molt of terephthalic acid and the dill component thereof consisting of at least 80 mow of butanediol-1,4.
Compared to aromatic polycarbonate these plates have improved theological properties and improved aging. They pass the fire tunnel test immediately and also after weathering or an extended period of several years.
Mixtures, containing polyalkylene terephthalates and polycarbonates, as well as applications thereof are known (e.g. USES 3,218,372, DEMOS 1,694,124, USES 3,730,767, JAY 7j401,639, USES 3,849,188, DOS 2,439,342 and DOS 2,708,381).
The plates according to the present invention do not seem however, to be described in these publications.
Polycarbonate films having a thickness of 100 em (0.1 mm) and low permeability to moisture are known which are produced from mixtures of 100 parts of bisphenol A polycarbonate and 10 to 70 parts of poly-(tetramethylene-terephthalates) (JAY 49-080,162 of 6.12.72, published on 2.8.74; KIWI. Vol. 82,1975, page 95, Ref. 59,321 b; only extracts available).
Films of polycarbonate-polyester mixtures are also known which, to 100 parts of bisphenol A polycarbonate, contain 25 to 150 parts of a specific poly(tetramethylene-terephthalate) containing > 10 mow of bis-(~-hydroxyethyl)-bis-phenol-A ether. Films of a thickness of 50 em having good mock-apical strength and a sealing temperature of 150C are for example described (JAY 49-113,849 of 5.3.73, published on 30.10.74; KIWI.
Vol. 83, 1975, page 71 Ref. 115,879 z; only extracts available).
lo A 22 232 _ ~3~3~L64 Mixtures of polycarbonates and polyesters in a ratio of 100:1 to 100, which can be processed into films and thin-walled articles, are also known, the polyester consisting of 20 to 100 mow % of alkaline isophthalate and of 80 to 0 mow % of alkaline terephthalate units.
(JAY 51-064,561 of 3.12.74, published on 4.6.76, KIWI. Vol.
85, 1976, page 36, Ref. 95,171 y).
Films and plates based on polyester-polycarbonate mixtures which consist of at most 50 by weight of polycarbonate and of at least 50 by weight of polyp ethylene terephthalate and which can optionally also contain other additives, are also known (see US Patents no. 3,956,229, no. 3,975,355 and DEMOS 2,647,565). The flame resistance of such mixtures is not mentioned in these literature references.
Polyester-polycarbonate mixtures which are stabilized by the addition of a polyamide are also known (DEMOS
2,751,969). The comparative examples A, I, D, E, F and G produced without polyamide do however use mixtures of polycarbonate and polybutylene terephthalate in a weight ratio of 1:1, and the comparative example P uses a mixture of 80 parts of polycarbonate and 20 parts of poly-(hexamethylene-sebacate). Neither is this literature reference concerned with the fire character rustics of plates made from polycarbonate-polyester mixtures.
Flame-resistant mixtures of polyalkylene terephtha-fates, organopolysiloxane-polycarbonate block copolymers and halogenated copolycarbonates, which are suitable for the production of films and plates, are known (see lo A 22 232 _ .

~LZ38~L64 US Patent 4,155,898). Mixtures of polyalkylene terephtha-fates, organopolysiloxane-polycarbonate block copolymers and Cook, which are also suitable for the production of films and plates, are also known (see US Patent 4,157,997).
Mixtures of specific halogen bisphenol polycarbonates and polyesters such as polybutylene terephthalates, which have improved flame-retarding properties, are also known (see DEMOS 3,023,796).
Finally strechted polycarbonate films consisting of mixtures of polycarbonates and 10-50 % by weight of polyesters are also known (JAY 56-034,428 of 31.8.79, pub-fished 6.4.81; KIWI. Vol. 95, 1981, page 54, Ref. 63,445 f, only extracts available).
High molecular weight aromatic polycarbonates according to the present invention are homopolycarbonates based on bisphenol A /2,2'-bis(4-hydroxyphenyl)propane/
or copolycarbonates based on bisphenol A and up to 20 %
by weight of Boyce (3,5-dimethyl-4-hydroxyphenyl)-propane and/or 1,1-bis-(4-hydroxyphenyl)-cyclohexane, or mixtures of BRA polycarbonates with other Capella-carbonates, it being possible for up to 20 mow % of 2,2-bis-(3,5-dimethyl-4-hydroxyphenyl)-propane and/or 1,1-bis-(4-hydroxyphenyl)-cyclohexane to be contained in the copolycarbonates in addition to bisphenol A
Polycarbonates based solely on 2,2-bis(4-hydroxy-phenyl)-propane or copolycarbonates with up to 5 % of the two other diphenols mentioned above are particularly preferred.
The aromatic polycarbonates may be produced according to known processes, i.e. according to the lo A 22 232 ~L~238~6~

melt-transesterification process using bisphenol A and diphenyl carbonate and according to the two-phase interracial process using bisphenols and phosgene, as described in the literature.
The aromatic polycarbonates should have a relative solution viscosity in SCHICK at 25C with a concentration of 0.5 g/100 ml of from 1.26 to 1.35.
The aromatic polycarbonates may, as is known, be branched by the incorporation of small quantities, pro-fireball quantities of from 0.05 to 2.0 ml % based on the diphenols used), of in- or more than trifunctional compounds, in particular compounds with three or more than three finlike hydroxy groups.
Polycarbonates of this type are described for example in German Offenlegungsschrift Nos. 1,570,533, 1,595,762, British Patent Specification No. 1,079,821, US Patent Specification No. Rye 27 682 and in German Patent No. 2,500,092.
Some of the compounds with three or more than three finlike hydroxy groups winch may be used are, for example, 2,4-bis-(hydroxyphenyl-isopropyl)-phenol, 2,6-bis-(2'-hydroxy-5'-methyl-benzyl)-4-methylphennot, 2-(4-hydroxyphenyl)-2-(2,4-dihydroxyphenyl)-propanno and 1,4-bis-(4,4"-dihydroxytriphenyl-methyl)-benzene.
Some further trifunctional compounds are 2,4-dihydroxybenzoic acid, trimesic acid, cyan uric chloride and3,3-bis-(4-hydroxy-3-methyl-phenyl)o2-oxo-2,3-dihyydro-insole (isatin-bis-cresol).
The polyesters according to the present invention are polyesters consisting mainly of terephthalic acid lo A 22 232 ~3~6~

and a dill selected from butanediol-1,4, ethanes dill and cyclohexanedimethanol-1,4, preferably butanediol-1,4.
The above-mentioned terephthalates may in addition to the specified glycol radicals, contain up to 20 Mel % of the radicals of other aliphatic dills usually having from

3 to 12 carbon atoms or cycloaliphatic dills usually having from 6 to 21 carbon atoms, e.g. those based on propane-Doyle, neopentyl glycol, pentanediol-1,5, hexanediol-1,6, 3-methylpentanediol-2,4, 2-methylpentanediol-2,4, and 2,2,4~trimethylpentanediol-1,3.
In addition to terephthalic acid esters, up to 15 mow %
of other dicarboxylic acid radicals may be contained e.g.
isophthalic acid, adipic acid, succinic acid, sebacic acid, naphthalene-2,6-dicarboxylic acid, diphenylcarboxy-fig acid, azelaic acid and cycl~hexanediacetic acid. The polyalkylene glycol terephthalates may, according to known processes, be produced for example by the transistor-ligation of terephthalic acid dialkyl ester and the corresponding dill ego. US Patent Nos. 2,647,885;
2,643,989; 2,534,028; 2,578,660; 2,742,494 and 2,901,466).
For the production thereof, we proceed for example from a lower alkyd ester of terephthalic acid preferably the dim ethyl ester, and transesterify the former with an excess of dill in the presence of suitable catalysts to produce the bishydroxy alkyd ester of terephthalic acid.
In the course of transesterification the starting them-portray of 140C is increased to 210-220~C. The alcohol which is released is distilled off. Condensation is then carried out at temperatures of from 210 to 280C, and at the same time the pressure is decreased in stages to less than 1 torn, and the excess dill is distilled off.

lo A 22 232 -~IL23l3~6~

The molecular weights My of the terephthalates usually lie between 30,000 and 80,000 and the molecular weights My of the mixed polyesters, based on terephthalic and isophthalic acid, also usually lie between 30,000 and 80,000. My may be determined by measuring the intrinsic viscosity (limit viscosity number, based on the zero concentration extrapolated value of the reduced specific viscosity) - IVY. - in phenol/o-dichlorobenzene (1/1), at 25C as a 5 % solution or using the REV value (reduced specific viscosity), which in this case means the specific viscosity value divided by the concentration of the measured solution. The RSV-value is determined in phenol-tetrachloroethane (60/40), at 20C with a 23 solution.
Aliphatic thermoplastic polyesters which are par-titularly preferred are polybutyleneterephthalates having a My of between 30,000 and 60,000.
The polycarbonate/polybutyleneterephthalate mixtures referred to in the present invention may additionally con-lain heat stabilizers, antioxidant, UV-stabilisers, flow auxiliaries and mould-release agents.
The fire tunnel test is carried out under the following conditions:

4 test rods having dimensions of I cm x 100 cm x original thickness are arranged vertically and at right angles to each other. After being subjected to 10 minutes of firing by a ring burner the burner is switched off. The fire tunnel test is deemed to be passed if:

e A 22 232 I
g - the average of the remaining lengths is at least 150 mm and no test-rod is completely burned down (remaining length 0 mm), - the average flue gas temperature does not exceed 200C.
Before the test the moldings are stored under normal conditions until their weight is constant. The test is carried out before outside exposure as well as after one and two years of outside exposure in a middle European climate. During outside exposure the test Hodges face south and form 45 angles to the ground.
The polycarbonate and polyester granulates are mixed and may either be directly processed into plates on an extrude or may be processed after preliminary homogeni-station on an extrude and subsequent granulation.
The results of the tests are shown in Table 1.

lo A 22 232 ~q~6~

E f , .

,. ., .> .> .> ., go . o o o o o o o x . ' E
E :

o Q ., o Q so 3 Jo o o.

C ¦ O! O o O a) lo A 22 232 .

I AL

1) polyco~bonaSe based on 2,2-bis-(4-hydroxyphenyl)-propane, net = 1.31 (measured in SCHICK, 2ûC, 0.5 g ~100 ml); the polyca~bonate contains 0.3 %
by weight of a US stabilizer.
2) Polybutylene terephthalate produced from terephtholic acid chloride and butanediol-1,4, having an intrinsic viscosity lo of 1.2, measured it ph~nol/o-dichlorobenzene (1/1) at 25C as a 5 % solution.
3) Cyclohexanedimethanol te~ephth~l~te having an REV
1û value (reduced specific viscosity) of 0.75 to 0.80, measured in phenol/tetrachloroethane (60/40) us a 23 % solution at 20C.
4) The PUT used in this test has an intrinsic viscosity (IVY.) of 0.87, measured as under 2).

5) The polycarbonate used in this test is a Boyce-hydroxyphenyl)-propane-polyc~rbonate having I- net = 1-33, which is branched by 0.5 mow %
of satin biscresol and contains 0.3 % by weight of a US stabilizer. ( Mel also assured in 2û SCHICK, 20C on 0.5 9/100 ml).

In place of solid plates of a thickness of 1 mm to 1û mm hollow-chamber plates of a thickness of about 8 to about 16 mm, for example of the type according to ESSAY
0,û54,856, also provide the properties according to the invention.
Thus the invention also relates to hollow-chamber plates ox a thickness of about 8 to about 16 my consisting of from 99 to 95 by weight of a high molecular weight aromatic polycarbonate based on from 80 to 10û mow % of lo A 22 232 ~2~16~ 23189-5719 bisphenol A and from 20 to 0 mow % of 2,2-bis-(3,5-dimethyl-4-hydroxyphenyl~propane and/or l,l-bis-(4-hydroxyphenyl)-cyclo-hexane, and from 1 to 5 % by weight of an aromatic-aliphatic, thermoplastic polyester, the acid component thereof consisting of at least 85 molt of terephthalic acid and the dill component thereof consisting of at least 80 mow % of butanediol-1,4, ethanediol-1,2 and/or cyclohexanedimethanol-1,4.

SUPPLEMENTARY DISCLOSURE
In a preferred embodiment of the plates of the present invention, the dill component of the thermoplastic polyester consists of at least 80 mow % of butanediol-1,4 and more preferably 100 mow % butanediol the plates according to the present invention preferably have a breadth between 50 cm and 300 cm and a minimum length of 50 cm and a maximum length up to 500 cm.

Claims (6)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A hollow chambered fire resistant plate having a thick-ness of 16 mm, which comprises a) from 99 to 95%, by weight of said plate, of high molecular weight aromatic polycarbonate, wherein said aromatic polycarbonate is based on i) from 80 to 100 mol % of bisphenol A, and ii) from 20 to 0 mol % of 2,2-bis-(3,5-dimethyl-4-hydroxyphenyl)-propane, 1,1-bis-(4-hydroxyphenyl)-cyclohexane, or combinations thereof, and b) 1 - 5%, by weight of said plate aromatic aliphatic thermoplastic polyester, the acid component thereof consisting of at least 85 mol % of terephthalic and the diol component thereof consisting of at least 80 mol % of butanediol-1,4.

2. A plate according to claim 1, wherein said aromatic poly-carbonate is based on 100 mol % of bisphenol A.

3. A plate according to claim 1 or 2 wherein the polyester is polybutylene terephthalate.

CLAIMS SUPPORTED BY THE SUPPLEMENTARY DISCLOSURE

4. A hollow chambered fire resistant polycarbonate plate comprising a) from 99 to 95%, by weight of said plate, high mole-cular weight aromatic polycarbonate, wherein said aromatic polycar-bonate is based on i) from 80 to 100 mol % bisphenol A, and ii) from 20 to 0 mol % 2,2-bis-(3,5-dimethyl-4-hydroxy-phenyl)-propane, 1,1-bis-(4-hydroxyphenyl)-cyclohexane, or combina-tions thereof, and b) 1 - 5%, by weight of said plate aromatic aliphatic, thermoplastic polyester, said thermoplastic polyester comprising at least 85 mol % terephthalic acid and said diol component com-prising at least 80 mol % butanediol-1,4 and wherein said plate has a thickness of 16 mm, a breadth of from 50 cm to 300 cm and a length of from 50 cm to 500 cm.

5. A plate according to claim 4, wherein said aromatic polycarbonate is based on 100 mol % of bisphenol A.

6. A plate according to claim 4 or 5, wherein the polyester is polybutylene terephthalate.