DE4232421A1 - Flame and hot wire resistant polycarbonate compsn. useful in electrical industry - using an aromatic polycarbonate contg. 1,1-bis(4-hydroxyphenyl)-3,3,5-tri:methyl-cyclohexane units and an aromatic bromine cpd. as flame retardant - Google Patents

Abstract

Thermoplastic, hot-wire resistant, polycarbonate composition contains an aromatic polycarbonate with MW of at least 10,000 and contg. units of formula (1); an aromatic bromine cpd. making up 0.5-6 wt.% of the mixture; and opt. 0.05-5 wt.% of other customary flame retardants. In formula (I), R1, R2 = H halogen, esp. Cl, Br, 1-8C alkyl, 5-6C cycloalkyl, 6-10C aryl esp. phenyl and 7-12C aralkyl pref phenyl- 1-4C alkyl and esp. benzyl; m = 4-7, pref. 4-5; R3, R4 = H, or 1-6C alkyl; and X = carbon; with the proviso that on at least one X atom R3 and R4 are both alkyl. Also claimed in the use of the composition to form hot-wire resistant injection mouldings. The polycarbonate pref. contains at least 10% of the structure (1) and pref. more than 30 mol.%. The pref. Br-contg. cpd. is a bromine-substd. divalent phenol, a brominate phthalimide or phthalimide sulphate or a brominated polymer. USE/ADVANTAGE - In the electrical and electronics industries. The composition fulfils both the flame-proof requirements of UL 94 and the hot-wire resistant properties of French standard C20-455. In an example, 98.53 pts.wt. of polycarbonate from 35 mol.% of 1,1-bis(4-hydroxyphenyl)-3,3,5-trimethyl-cyclohexane and 65 mol.% of bisphenol A, 1 pt.wt. of an oligocarbonate from tetrabromobisphenol A, 0.15 pts.wt. of N,N-hexamethylene-bis-tetrabromobisphenol A, 0.15 pts.wt. of N,N-hexamethylene-bis-tetrachlorophthalimide and 0.5 pts.wt. of PTFE were mixed in an extruder and injection moulded. The composition showed a UL 94 figure of V-2 and a C20-455 result of tm = 14 and S5 = 18, with an oxygen index of 36.

Description

Thermoplastic materials are used in electrical / Electronics area with stringent requirements of their inflammatory behavior.

So thermoplastic molding compounds with live parts in contact, special Requirements for testing with electrical ignition meet sources.

In various standards and device specifications to demonstrate resistance to electrical Ignition sources required the glow wire test.

The glow wire test is in the Norme Francaise C 20-455 (Catalogne APNOR 1984). This is invoked the device specification of the Électricit´ de France, EdF HN 60-E02 whose assessment criteria in Électricit´ de France, EdF HN 60-502 are listed. The standardization documents are published by: service normalization et brevets d′´lectricit´ de France.  

According to this, the glow wire test is passed if the sum of the extinguishing time 55 <25 s and the max. Deletion time: t _M 15 s.

In doing so, they may use them as documents in the examination materials neither ignited nor scorched become.

In contrast to the fire tests according to the Underwriters Laboratories UL 94 standard and the ASTM-D 2863-87 (O ₂ index) standard, where resistance to open flame tests is required, the Francaise standard - C 20-455 resistance to an electrical ignition source.

These different test methods are therefore not available Correlation and result in same, flame retardant equipped thermoplastic molding compounds too strong different ratings.

Flame-retardant thermoplastic polycarbonate molding compounds are z. B. in DE-OS 39 11 558; DE-OS 38 32 396 and US Patent No. 49 82 014. These masses exist also fire tests with open flame according to UL 94 and ASTM-D 2863-87, but fail in the filament Test according to NF C 20-455 at higher test temperatures.

According to the invention, molding compositions with aromatic bromine Additives provided that meet both the requirements according to UL 94 as well as the Francaise C 20-455 standard to fill.  

The invention relates to thermoplastic, glow wire-resistant polycarbonate molding compounds, which preferred also meet the requirements of UL 94 from:

• A) Polycarbonate based on substituted Dihydroxyphenylalkanes and optionally in addition to other polycarbonates
• B) aromatic bromine compounds in one Amount that the bromine content of the mixture of A + B 0.5 to 6 wt .-% is
• C) and usual fire protection additives (except B).

Polycarbonate A

Polycarbonates A in the sense of the invention are high molecular weight, thermoplastic, aromatic polycarbonates with _w (weight average molecular weight) of at least 10,000, preferably from 20,000 to 300,000, which contain bifunctional carbonate structural units of the formula (I),

wherein
R ¹ and R ² independently of one another are hydrogen, halogen, preferably chlorine or bromine, C ₁ -C ₈ alkyl, C ₅ -C ₆ cycloalkyl, C ₆ -C ₁₀ aryl, preferably phenyl, and C ₇ -C ₁₂ - Aralkyl, preferably phenyl-C ₁ -C ₄ -alkyl, in particular benzyl,
m is an integer from 4 to 7, preferably 4 or 5,
R ³ and R ^{4 can be} selected individually for each X, independently of one another hydrogen or C ₁ -C ₆ alkyl and
X is carbon, with the proviso that on at least one atom XR ³ and R ^{4 are} both alkyl.

The starting products for the polycarbonates A are dihydroxy diphenylcycloalkanes of the formula (Ia)

wherein
X, R ¹ , R ² , R ³ , R ⁴ and m have the meaning given for the formula (I).

Alkyl on 1 to 2 atoms, in particular only on one atom X, R ³ and R ^4, are preferred at the same time.

The preferred alkyl radical is methyl; the X atoms in α digits to the di-phenyl-substituted C atom (C-1) preferably not dialkyl-substituted; Alkyl disubstitution in the β-position to C-1 preferred.

Dihydroxydiphenylcycloalkanes with 5 and 6 ring carbon atoms in the cycloaliphatic radical (m = 4 or 5 in formula (Ia)), for example the diphenols Formulas (Ib) to (Id),

the 1,1-bis (4-hydroxyphenyl) -3,3,5-trimethyl cyclohexane (formula Ib with R ¹ and R ² being H) being particularly preferred. The polycarbonates A can be prepared from diphenols of the formula (Ia) in accordance with German patent application P 3 832 396.6 (LeA 26 344).

Both a diphenol of the formula (Ia) under Bil formation of homopolycarbonates as well as several diphenols of the formula (Ia) to form copolycarbonates be applied.

In addition, the diphenols of the formula (Ia) can also be used in Mixture with other diphenols, for example with the of the formula (Ie)

HO-Z-OH (Ie)

for the production of high molecular, thermoplastic, aromatic polycarbonates can be used.

Suitable other diphenols of the formula (Ie) are those in which Z is an aromatic radical with 6 to 30 C atoms which contains one or more aromatic nuclei can, can be substituted and aliphatic radicals or cycloaliphatic radicals other than that of the formula (Ia) or can contain heteroatoms as bridge members.

Examples of the diphenols of the formula (Ie) are
Hydroquinone,
Resorcinol,
Dihydroxybiphenyls,
Bis (hydroxyphenyl) alkanes,
Bis (hydroxyphenyl) cycloalkanes,
Bis (hydroxyphenyl) sulfides,
Bis (hydroxyphenyl) ether,
Bis (hydroxyphenyl) ketones,
Bis (hydroxyphenyl) sulfones,
Bis (hydroxyphenyl) sulfoxides,
α, α′-bis (hydroxyphenyl) diisopropylbenzenes
as well as their keralkylated and nuclear halogenated compounds.

These and other suitable diphenols are e.g. Tie U.S. Patent 3,028,365, 2,999,835, 3,148,172, 3,275,601, 2 991 273, 3 271 367, 3 062 781, 2 970 131 and 2,999,846, in German Offenlegungsschriften 1 570 703, 2 063 050, 2 063 052, 2 211 956, the French Patent 1,561,518 and in Monograph "Schnell, Chemistry and Physics of Polycarbonates, Interscience Publishers, New York 1964 ", described.

Preferred other diphenols are, for example:
4,4'-dihydroxybiphenyl,
2,2-bis (4-hydroxyphenyl) propane,
2,4-bis (4-hydroxyphenyl) 2-methylbutane,
1,1-bis (4-hydroxyphenyl) cyclohexane,
α, α-bis (4-hydroxyphenyl) -p-diisopropylbenzene,
2,2-bis (3-methyl-4-hydroxyphenyl) propane,
2,2-bis (3-chloro-4-hydroxyphenyl) propane,
Bis- (3,5-dimethyl-4-hydroxyphenyl) methane,
2,2-bis (3,5-dimethyl-4-hydroxyphenyl) propane,
Bis (3,5-dimethyl-4-hydroxyphenyl) sulfone,
2,4-bis (3,5-dimethyl-4-hydroxyphenyl) -2-methylbutane,
1,1-bis (3,5-dimethyl-4-hydroxyphenyl) cyclohexane,
α, α-bis (3,5-dimethyl-4-hydroxyphenyl) -p-diisopropyl-benzene,
2,2-bis (3,5-dichloro-4-hydroxyphenyl) propane and
2,2-bis (3,5-dibromo-4-hydroxyphenyl) propane.

Particularly preferred diphenols of the formula (Ie) are, for example:
2,2-bis (4-hydroxyphenyl) propane,
2,2-bis (3,5-dimethyl-4-hydroxyphenyl) propane,
2,2-bis (3,5-dichloro-4-hydroxyphenyl) propane,
2,2-bis (3,5-dibromo-4-hydroxyphenyl) propane and
1,1-bis (4-hydroxyphenyl) cyclohexane.

In particular, 2,2-bis (4-hydroxyphenyl) propane is before moves. The other diphenols can be used both individually and can also be used in a mixture.

The molar ratio of diphenols of formula (Ia) to the other diphenols of the formula which may also be used (Ie) should be between 100 mol%, (Ia) to 0 mol% (Ie) and 2 mol% (Ia) to 98 mol% (Ie), preferably between 100 mol% (Ia) to 0 mol% (Ie) and 5 mol% (Ia) to 95 mol% (Ie) and in particular between 100 mol% (Ia) to 0 mol% (Ie) and 10 mol% (Ia) to 90 mol% (Ie) and very particularly between 100 mol% (Ia) to 0 mol% (Ie) and 20 mol% (Ia) to 80 mol% (Ie).  

The high molecular weight polycarbonates from the diphenols of Formula (Ia), possibly in combination with other diphenols can according to the known polycarbonate manufacturing ver drive are manufactured. The various diphenols both statistically and in blocks be linked together.

The polycarbonates according to the invention can be branched in a manner known per se. If the branching is desired, it can be carried out in a known manner by condensing in small amounts, preferably amounts between 0.05 and 2.0 mol% (based on diphenols used), of three- or more than three-functional compounds, in particular those with three or more than three phenolic hydroxyl groups can be achieved. Some branching agents with three or more than three phenolic hydroxyl groups are:
Phlorogulcin,
4,6-dimethyl-2,4,6-tri- (4-hydroxyphenyl) heptane-2,
4,6-dimethyl-2,4,6-tri- (4-hydroxyphenyl) heptane,
1,3,5-tri- (4-hydroxyphenyl) benzene,
1,1,1-tri- (4-hydroxyphenyl) ethane,
Tri- (4-hydroxyphenyl) phenylmethane,
2,2-bis (4,4-bis (4-hydroxyphenyl) cyclohexyl) propane,
2,4-bis (4-hydroxyphenyl-isopropyl) phenol,
2,6-bis (2-hydroxy-5-methylbenzyl) -4-methylphenol,
2- (4-hydroxyphenyl) -2- (2,4-dihydroxylphenyl) propane,
Hexa- (4- (4-hydroxyphenyl-isopropyl) phenyl) site hotere-phthalic acid ester,
Tetra (4-hydroxyphenyl) methane,
Tetra- [4- (4-hydroxyphenyl-isopropyl) phenoxy] methane
and
1,4-bis- [4 ′ -, 4 ′ ′ - dihydroxytriphenyl) methyl] benzene.

Some of the other three-functional compounds are 2,4-dihydroxybenzoic acid, trimesic acid, cyanuric chloride and 3,3-bis (3-methyl-4-hydroxyphenyl) -2-oxo-2,3-di hydroindole.

Monofunctional compounds in conventional concentrations serve as chain terminators for the known regulation of the molecular weight of the polycarbonates A. Ge suitable connections are such. B. phenol, tert-butylphenols or other alkyl-C ₁ -C ₇ -substituted phenols. Small amounts of phenols of the formula (If) are particularly suitable for regulating the molecular weight

wherein R represents a branched C ₈ and / or C ₉ alkyl radical. The proportion of CH ₃ protons in the alkyl radical R is preferably between 47 and 89% and the proportion of CH and CH ₂ protons between 53 and 11%; also preferred before R is in the o- and / or p-position to the OH group, and particularly preferably the upper limit of the ortho portion 20%. The chain terminators are generally used in quantities of 0.5 to 10, preferably 1.5 to 8 mol%, based on the diphenols used.

The polycarbonates A can preferably after the phase interface behavior (cf. H. Schnell "Chemistry and Physics of Polycarbonates ", Polymer Reviews, Vol. IX, Page 33 ff., Interscience Publ. 1964) in itself known way.

The diphenols of the formula (Ia) are aqueous alkaline phase dissolved. For the production of copoly Carbonates with other diphenols are mixtures of Diphenols of the formula (Ia) and the other diphenols, for example those of the formula (Ie) used. For Regulation of molecular weight can be chain terminators e.g. B. the formula (If) are added. Then in Ge dissolve in the presence of an inert, preferably polycarbonate the organic phase with phosgene according to the method of Phase interface condensation implemented. The reaction temperature is between 0 ° C and 40 ° C.

The branching agents that may be used (preferred 0.05 to 2.0 mol%) can either with the diphenols be presented in the aqueous alkaline phase or dissolved in the organic solvent before phosgeny tion can be added. In addition to the diphenols of the formula (Ia) and possibly other diphenols (Ie) can also be their Mono- and / or bis-chlorocarbonic acid ester used be dissolved in organic solvents be added. The amount of chain terminators as well branches then depend on the molar amount of diphenolate residues corresponding to formula (Ia) and, if appropriate Formula (Ie); with the use of chlorinated carbon dioxide esters can ent the amount of phosgene in a known manner be reduced speaking.  

Suitable organic solvents for the chains crusher and, if necessary, for the branches and the chlorine carbon Lens acid esters are, for example, methylene chloride, Chlorobenzene, acetone, acetonitrile and mixtures of these Solvents, especially mixtures of methylene chloride and chlorobenzene. Possibly. can the used Chain terminator and branch in the same solvent be solved.

As an organic phase for the interfacial poly condensation serves, for example, methylene chloride, Chlorobenzene and mixtures of methylene chloride and Chlorobenzene.

NaOH, for example, serves as the aqueous alkaline phase. Solution. The production of the polycarbonate A after Phase boundary method can be done in the usual way Catalysts such as tertiary amines, especially tertiary ones aliphatic amines such as tributylamine or triethylamine catalyzed; the catalysts can be used in quantities from 0.05 to 10 mol% based on moles of used Diphenols can be used. The catalysts can before the start of phosgenation or during or after be added to the phosgenation.

The polycarbonates A can by the known method in a homogeneous phase, the so-called "pyridine process" and according to the known melt transesterification process using, for example, diphenyl carbonate instead of phosgene.  

The polycarbonates A preferably have molecular weights M _w (weight average, determined by money chromatography after prior calibration) of at least 10,000, particularly preferably from 20,000 to 300,000 and in particular from 20,000 to 80,000. They can be linear or branched, they are homopolycarbonates or copolycarbonates based on the diphenols of the formula (Ia).

The incorporation of the diphenols of the formula (Ia) gave rise to new polycarbonates with high heat resistance, which also have a good property profile. This applies in particular to the polycarbonates based on the diphenols of the formula (Ia) in which is 4 or 5, and very particularly to the polycarbonates based on the diphenols (Ib), in which R ¹ and R ² independently of one another for the formula ( Ia) have the meaning given and are particularly preferably hydrogen.

The particularly preferred polycarbonates A are therefore those in which structural units of the formula (I) m = 4 or 5 and especially those from units of Formula (Ig)

wherein R ¹ and R ^{2 have} the meaning given for formula (I), but are particularly preferably hydrogen.

These polycarbonates based on the diphenols of the formula (Ib), in which R ¹ and R ² in particular are hydrogen, also have good UV stability and good flow behavior in the melt in addition to the high heat resistance, which was not to be expected.

Through any composition with other diphenols, in particular with those of the formula (Ie) can also the polycarbonate properties vary favorably Ren. In such copolycarbonates, the diphenols are the Formula (Ia) in amounts of 100 mol% to 2 mol% preferably in amounts of 100 mol% to 5 mol% and ins especially in amounts from 100 mol% to 10 mol% and whole especially from 100 mol% to 20 mol%, based on the Total amount of 100 mol% of diphenol units in the poly contain carbonates.

Aromatic bromine compounds B

Aromatic bromine-containing organic come as B) Connections in question. They are in such quantities used that the molding compositions 0.5 to 6 wt .-%, preferably contain 3 to 5 wt .-% bromine.

Particularly preferred organic bromine compounds are:

• 1. Oligomers of a bromo-substituted dihydric phenol. The preferred oligomers contain 2 to 20 units of the formula wherein
  R ¹ and R ^{2 are} hydrogen, alkyl having 1 to 4 carbon atoms or phenol
  X ¹ and X ^{2 is} bromine and
  n and r are an integer from 1 to 4 and
  y is 0 or 1,
  which are linked by carbonate, ether or ether alkyl groups.
  These oligomers are still not very volatile at 200 ° C and soften at less than 300 ° C.
• 2. Brominated phthalimides and phthalimide sulfates of the general formulas (I) or (II) or mixtures thereof wherein
  RH, C ₁ -C ₄ alkyl, C ₆ H ₅ , C ₁₀ H ₇ , C ₆ H ₃ X ₂ or C ₆ H ₂ X ₃ where X = bromine and where
  R 'is a single formation, C ₂ -C ₄ alkylene, C ₆ H ₄ or p-diphenylene and Z is bromine.
• 3. Brominated polymers z. B. Polypentabromobenzyl acrylate, polybromostyrene.

Fire protection additives C

All known for this purpose come as fire protection additive C. Compounds into consideration, for example those in DE-OS 27 40 880, DE-OS 30 35 357, DE-OS 32 33 617, DE-OS 40 27 104 and described in DE-OS 39 11 558.

These are preferred in amounts of 0.05 to 5% by weight 0.15 to 2 wt .-%, based on molding compositions, used.

Particularly preferred flame retardant additives are ammonium or alkali salts of aliphatic and aromatic sul fonic acid derivatives and halogenated phthalimides. At Games are potassium perfluorobutane sulfonate, potassium diphenyl sulfone sulfonate and N, N'-hexamethylene-bis-tetrachlor phthalimide. The compositions of the invention can be further Thermoplastics, such as B. by H. Seechtling in plastic Paperback, Carl-Hanser-Verlag, Munich, Vienna (1989) described.

The molding compositions according to the invention can be used with conventional Quantities of fillers and reinforcing materials are provided, as by W. Retting in Kunststoff-Handbuch 1 (1990) described. You can also use pigments, stabilizers, Flow aids, mold release agents and antistatic agents contain.

Examples used material

I. Aromatic polycarbonate from 35 mol% 1,1-bis (4-hydroxyphenyl) -3,3,5-trimethyl-cyclohexane and 65% by weight bisphenol A with a relative viscosity, measured in methylene chloride at 25 ° C of 1.29 (0.5% by weight solution)
II. Aromatic oligocarbonate from tetrabromobisphenol A with a relative viscosity of 1.05. Bromine contains 50% by weight.
III. Aromatic brominated bisphenol A epoxy resin with 51% bromine from Makhteshim, Chem. Works Ltd.
IV. Potassium perfluorobutane sulfonate
V. Potassium diphenyl sulfone sulfonate
VI. N, N'-hexamethylene-bis-tetrachlorophthalimide
VII. Hostaflon TF® 2021 polytetrafluoroethylene polymer from Hoechst AG.

Table 1

Composition of the molding compounds (parts by weight)

Composition of the molding compounds (parts by weight) Production and testing of molding compounds

The materials were on a twin screw extruder from Werner & Pfleiderer of type ZSK 53 or ZSK 30 compounded at 300 ° C to 320 ° C and added to granules is working.  

The granules were then added at 320 to 340 ° C Injection molded test specimens (unit: Arburg Allrounder 320, clamping force 75 t, screw diameter 25 mm) and subjected to the following tests:

• - Glow wire test according to NF C 20-455 / EdF HN 60 S02
• - Fire test according to Underwriter Laboratories (UL 94)
• - O ₂ index according to ASTM-D2863-87

Table 2

Test data

Tables 1 and 2 show that the molding compositions according to the invention have the resistance to glow wire according to NF C 20-455 / EdF HN 60 SO ₂ and the classification UL 94 V-0 (1.6 mm).

The examples given as a comparison represent the current state of the art; despite high O ₂ indices, the products obtained either fail the filament resistance.

Claims (4)

1. Thermoplastic, glow wire resistant polycarbonate molding compounds

• A: thermoplastic, aromatic polycarbonate with _w (weight average molecular weight) of at least 10,000 containing the bifunctional carbonate structural units of the formula (I), wherein
  R ¹ and R ² independently of one another hydrogen, halogen, C ₁ -C ₈ alkyl, C ₅ -C ₆ cycloalkyl, C ₆ - C ₁₀ aralkyl
  m is an integer from 4 to 7,
  R ³ and R ^{4 can be} selected individually for each X, independently of one another hydrogen or C ₁ -C ₆ alkyl
  and
  X is carbon,
  with the proviso that on at least one atom XR ³ and R ⁴ mean alkyl at the same time.
• B: aromatic bromine compounds in such an amount that the mass of A and B contains 0.5 to 6 wt .-% bromine.
• C: optionally and 0.05 to 5% by weight, based on molding compound from conventional fire protection additives (except those according to B).

2. Mixtures according to claim 1, wherein the aromatic Polycarbonate at least 10 mol% of the bifunction light carbonate structural unit of the formula (I), preferably contains more than 30 mol%. 3. Mixtures according to claim 1, wherein B is an oligomer a bromo-substituted dihydric phenol brominated phthalimide or phthalimide sulfate or is a brominated polymer. 4. Use of the molding compositions according to claim 1 for Her provision of glow wire resistant injection molded parts.