DE4024670A1 - Fire retardant mixts. for polycarbonate(s) - comprise boron phosphate, aromatic alkali sulphonate and tetra:fluoroethylene polymer - Google Patents

Abstract

Mixts. (I) are claimed, contg. (1) 1-12 pts. wt. BPO4, (b) 0.05-1 pt. wt. aromatic alkali sulphonate and (c) 0.04-1 pt. wt. TFE polymer, combined in any relative wt. ratio. Pref. (a) is a known cpd. (see, e.g. "Gmelins Handbuch der anorganischem Chemie", 8th Ed., Phosphorus Part C, System No. 16, pp. 612-4); pref., (b) is e.g. K benzenesulphonate, Na p-toluenesulphonate, etc., (c) is PTFE, TFE/HFP copolymer, etc.; (II) is based on Bisphenol A or 1,1-bis-(4-hydroxyphenyl) -3,3,5-trimethylcyclohexane. USE/ADVANTAGE - (I) are useful as fire retardants for thermoplastic aromatic, halogen-free, sulphur-free and phosphorus-free polycarbonates (II). Also claimed are: (1) a process for incorporating (I) in (II), by compounding 0.04-12 wt.% (I) with 100 wt.% (II) in a twin-screw extruder or internal kneader at 200-350 deg.C. and (2) polycarbonate moulding materials obtd. by this process.

Description

The present invention relates to mixtures consisting of

• a) 1 to 12 parts by weight BPO ₄ ,
• b) 0.05 to 1 part by weight of an aromatic Alkalisulfonate and
• c) 0.04 to 1 part by weight of a tetrafluoroethylene polymer where indicated for the components a) b) and c) Parts by weight in any relative weight ratio can be combined.

Preferred amounts are for

• a) 2 to 10 parts by weight, for
• b) 0.1 to 0.8 parts by weight and for
• c) 0.08 to 1 part by weight.

The mixtures according to the invention serve as flame retardants medium combinations for halogen-free, sulfur-free and phosphorus-free polycarbonates, wherein a flame retardancy from V-O to UL-Test Subject 94 for specimens from 1.6 mm thickness is achieved.

To tetrafluoroethylene polymer containing polycarbonates, as described for example in GB PS 9 38 931 are, for example, to adjust flame retardant the introduction of halogen into the polycarbonate (see DE-PS 22 11 826), optionally in combination with earth Alkalicarbonaten (US Patent 38 51 174), or the Zu rate of organic alkali or alkaline earth salts (see US Patent 43 91 935 and DE-OS 29 48 439) or of Antimony oxide (see DE-OS 24 00 044) or the additive of inorganic alkali metal salts (see DE-OS 28 00 923) or the addition of alkali salts and the introduction of halogen in the polycarbonate (see Jap. Patent Pub Lication No. 49-88 944 and US Patent 42 08 489 (Le A 17 759-US). The production and processing of such Molding compounds, especially the production of large planar parts, however, presents some difficulties opportunities.

In contrast, the use of the invention leads Mixtures to flame-retardant, polytetrafluoroethylene-hal polycarbonate molding compounds, which also in Verarbei temperatures 300 ° C with a consistently good flame Adversity of VO in 1.6 mmm thickness few to none Show surface streaks.

Flame-resistant molding compounds with good surface qualities sond already from DE-OS 34 42 281 (Le A 23 338) be knows the good surface qualities by Koa gulation of Tetrafluorethylenpolymerisate with low Amounts of graft polymers have been achieved.

From EP-OS 02 07 369 (Le A 23 940) and DE-OS 38 19 081 (Le A 26 045) are phosphate esters and Phos phonate ester in combination with tetrafluoroethylene-poly merisaten as a flame retardant combination for poly Carbonate molding compounds known.

In the latter case, however, the incorporation of the im general low-melting and volatile Phos phosphate or phosphonate ester in the polycarbonate Molding compounds certain difficulties.

To avoid such difficulties, above all concerning the volatility of the phosphoric esters were determined according to DE-OS 38 24 356 (Le A 26 015) less volatile Phos phorester used. However, these have the disadvantage that here, too, the production conditions inside knead only with great difficulty kept constant can be. The less volatile phosphorous esters can only be used under special process conditions incorporate into the polycarbonate melt. Inside Knockern must first melted the polycarbonate Then, in the hot melt, the phosphorus ester to be able to work in. This leads to uneven Distribution of the phosphorus ester.  

In twin-screw extruders is a Aufschmelzvorrich tion for the phosphorous esters and a separate liquid speed entry station required.

The addition of boron phosphate (BPO ₄ ) to polycarbonates used according to DE-AS 12 39 471 (Ue 2093) or US-PS 34 04 122 for the stabilization of polycarbonates against the degradation of moisture and DE-AS 11 94 142 (Ue 2147) or US-PS 33 22 719 as costabilizer for UV stabilization of Polycarbo naten.

As a flame retardant for polycarbonate boron phosphate (BPO ₄ ) is therefore not suggested.

The subject of the present invention is thus also the Use of the three-component mixture according to the invention a) to c) as a flame retardant for thermoplastic aromatic, halogen-free, sulfur-free and phosphorus free polycarbonates, wherein a total of 0.04 wt .-% to 12 Wt .-%, preferably 0.2 wt .-% to 8 wt .-% of the three component mixture, per 100% by weight of polycarbonate be set.

The boron phosphate (BPO ₄ ) to be mixed according to the invention as component a) is known. (See, for example, "Gmelin's Handbook of Inorganic Chemistry", 8th Edition, 1965, Phosphor Part C, System Number 16, pages 612-614).

According to the invention suitable aromatic alkali metal sulphonates according to component b) are lithium, sodium and potassium salts of aromatic mono- or disulfonic acids with preferably 6 to 30 carbon atoms. Examples of alkali sulph Fonates of aromatic mono- and disulfonic acid are the Ka lium salt of benzenesulfonic acid, the sodium salt of di phenylsulfone sulfonic acid, the potassium salt of diphenyl sulfonic acid, the sodium salt of paratoluene sulfonic acid and the potassium salt of paratoluene sulfonic acid.

Tetrafluoroethylene polymers according to component c) which are suitable according to the invention are polymers having fluorine contents of 64 to 76% by weight, preferably 70 to 76% by weight. In games are polytetrafluoroethylene, tetrafluoroethylene-hexafluoropropylene copolymers or tetrafluoroethylene copolymers with small amounts of fluorine-free copoly merisierbarer ethylenically unsaturated monomers. The polymers are known. They can be prepared by known methods, for example by polymerization of tetrafluoroethylene in an aqueous medium with a free radical catalyst, for example, sodium, potassium or Ammoniumperoxidi sulfate at pressures of 7 to 71 kg / cm ² and at temperatures of 0 Tempe to 200 ° C, preferably at temperatures of 20 to 100 ° C. (For further details see, for example, US Patent 23 93 967).

The polytetrafluoroethylenes which are suitable according to the invention should preferably have weight average molecular weights M _{w of} between 10 ⁵ and 10 ⁶ , particle sizes of between 0.05 μm and 20 μm and densities in the range of 1.2 to 1.9 g / cm ³ .

The mixing of the individual components a), b) and c) can in a known manner both successively as well occur simultaneously, both at about 20 ° C. (Room temperature) as well as at higher temperature.

The mixture may be in bulk or in solution, wherein the removal of the solvent by evaporation done in a known manner. Suitable solvents for the three-component mixture according to the invention are di chloromethane, trichloromethane, tetrachloromethane and tetra hydrofuran.

According to the invention flame-retardant to be equipped thermopla Static, aromatic halogen-free, sulfur-free and Phosphorus-free polycarbonates are those based on Diphenols of the formula (1)

wherein A is a single bond, a C ₁ -C ₅ alkylene, a C ₂ - C ₅ alkylidene or C ₅ -C ₆ cycloalkylidene, X = 0,1 or 2 and "n" = 1 or 0, wherein the C ₅ -C ₆ -cycloalkylidene by 1, 2 or 3 C ₁ -C ₄ -alkoxy radicals, preferably, methyl radicals, may be substituted.

Polycarbonates suitable according to the invention are both Homopolycarbonates as well as copolycarbonates.  

The diphenols of the formula (I) are either literature known or forth by literature methods adjustable.

The preparation of the poly suitable according to the invention carbonate is known from the literature and may, for example with phosgene by the phase interface method or with phosgene according to the homogeneous phase method (the so-called pyridine method), wherein the each to be adjusted molecular weight in known Way through an appropriate amount of known Chain breakers is achieved.

The polycarbonates which are suitable according to the invention have average weight-average molecular weights (M _w , measured, for example, by ultracentrifugation or scattering light measurement) of from 15,000 to 200,000, preferably from 20,000 to 80,000.

Suitable diphenols of the formula (I) are, for example, Hydroquinone, resorcinol, 4,4'-dihydroxydiphenyl, 2,2-bis (4-hydroxyphenyl) -propane, 2,4-bis (4-hydroxyphenyl) -2 methylbutane, 1,1-bis (4-hydroxyphenyl) cyclohexane, 2,2- Bis (3-methyl-4-hydroxyphenyl) -propane, 2,2-bis (3,5-di methyl-4-hydroxyphenyl) -propane, bis (3,5-dimethyl-4-hy droxyphenyl) methane, bis (4-hydroxyphenyl) methane and 1,1-bis (4-hydroxyphenyl) -3,3,5-trimethylcyclohexane.

Preferred diphenols of the formula (I) are 2,2-bis (4-hy droxyphenyl) propane, 1,1-bis (4-hydroxyphenyl) cyclo hexane and 1,1-bis (4-hydroxyphenyl) -3,3,5-trimethyl cyclohexane.  

The polycarbonates which are suitable according to the invention can be described in be known branches, preferably by the incorporation of 0.05-2.0 mol%, based on the Sum of diphenols used, in three or more than trifunctional compounds, such as those with three or more than three phenolic OH groups.

Preferred polycarbonates are in addition to homopolycarbo from 2,2-bis- (4-hydroxyphenyl) -propane or 1,1- Bis- (4-hydroxyphenyl) -3,3,5-trimethylcyclohexane the Co polycarbonates from these two diphenols and the Copolycarbonates of these diphenols with up to 15 mol%, based on molar sum of diphenols, on the other standing diphenols of the formula (I).

Halogen-free polycarbonates within the meaning of the present invention Invention means that the polycarbonates of halogen free diphenols, halogen-free chain terminators and optionally halogen-free branching agents are constructed, wherein the content of minor ppm amounts ver soapable chlorine, resulting, for example, from the Preparation of polycarbonates with phosgene after Phase interface method, not as containing halogen in Sense of the invention is to be considered. Such polycarbo nate with ppm levels of saponifiable chlorine are halo genfreie polycarbonates in the context of the present invention making. Ensprechendes gives for sulfur-free and phos phosphorus free polycarbonates.  

The incorporation of the mixtures according to the invention a) + b) + c) in the flame retardant to be equipped polycarbonates takes place advantageously on twin-screw extruders for fully continuous operation. For the disconti The inner kneader can also be used for a long-term operation become. Baubury laboratory kneaders are for smaller Approaches advantageous.

The subject of the present invention is thus also a Process for incorporating the Mi. mixtures consisting of the components a) + b) + c) in thermoplastic, aromatic halogen-free, sulfur free and phosphorus-free polycarbonates thereby ge characterized in that one Mischun the invention gene the thermoplastic polycarbonates about Zwewel lenschnecken extruder or in internal kneaders at tempera between 200 ° C and 350 ° C, preferably between 220 ° C and 330 ° C in amounts of 0.04 wt .-% to 12 wt .-%, each based on 100 wt .-% polycarbonate einarbei tet.

The present invention also relates to Flame obtainable by this process according to the invention adverse polycarbonate molding compounds.

For the preparation of the flame-retardant according to the invention Polycarbonate molding compounds can be the components of tri-mixtures a), b) and c) according to the invention also one after the other in any order the poly carbonates are incorporated.  

A preliminary mixing of the components a) + b) + c) is thus not necessarily required.

The incorporation of components a) + b) + c) in the Polycarbonates can also be prepared by the known masterbatch Process via a concentrate in the polycarbonate, which then by mixing with more polycarbonate to the desired final concentration of components a), b) and c) is diluted in the polycarbonate molding composition.

The molding compositions obtainable according to the invention can be added to Moldings of any kind, including foils in known Be processed. The processing to Formkör For example, pern takes place according to known injection molding process at temperatures between 270 ° C and 350 ° C.

The molding compositions obtainable according to the invention can be used before or at any time during their further processing Moldings nor the usual for the polycarbonates Additives such as stabilizers, pigments, superplasticizers, Mold release agent and / or antistatic agents in the usual Quantities are incorporated.

The molding compositions according to the invention can be obtained in Areas for which a high flame retardancy combined with good mechanical polycarbonate properties be required to be used, eg. B. in the electric area for switch covers, sockets, power strips, Switch boxes, telephone cases, etc., in the household sector for Housing parts of irons, coffee machines and in particular especially in large appliances z. B. for computer case parts.

Examples 1. Preparation of a three-component mixture consisting from a) + b) + c)

5 parts by weight of BPO ₄ , 0.5 parts by weight of potassium benzene sulphonate and 5 parts by weight of polytetrafluoroethylene with Mn of 570,000, a particle size of about 0.23 μm and a density of 1.5 g / m ³ are stirred in tetrahydrofuran and the tetrahydrofuran evaporated at closing.

2. Preparation of a flame-retardant polycarbonate mold Dimensions a) General manufacturing instructions

The molding compound is used in a Banbury laboratory compounded kneader. The main parts of the Banbury Internal Kneader of the company Ponini-Farrel are:

• a) a pneumatically controlled stamp cylinder, the material to be mixed into the chamber press and hold it during the mixing process the chamber holds,
• b) Hopper: All mixing material becomes pressed through the open flap,  
• c) mixing chamber: the chamber jackets are for water, Steam or other heating prepared,
• d) Two rotors for the mixing process,
• e) Folding saddle for ejecting the melt.

The powdery mixture of the components

polycarbonate 100 parts Tetrafluoroethylene 5 parts boron phosphate 5 parts alkali sulfonate 0.5 parts

is fed through the filling into the internal kneader given and the punch cylinder lowered (stamp pressure 2.5 bar). After 1 to 2 minutes is the powder melted. The stamp becomes minute-by-minute Cylinder 3 times temporarily relieved and relieved (Melting temperature 170 ° C). The homogenized Melt is rolled into a band and on closing the band granulated.

The molding compositions thus obtained are on a Injection molding machine (make Arburg 270-210-500 Screws: ⌀ 30 mm) Standard small bars processed.  

2 B)

• 1. Recipe 1 is composed of
  • 1.1 100 parts by weight of a bisphenol A homopoly carbonate having a relative viscosity of 1.26, measured in CH₂Cl₂ at 20 ° C and a concentration of 0.5 g in 100 ml,
  • 1.2 5 parts by weight of polytetrafluoroethylene, n 570 000, particle size approx. 0.23 μm, density 1.5 g / m³,
  • 1.3 5 parts by weight BPO₄ and
  • 1.4 0.5 parts by weight of potassium benzenesulfonate.

The resulting molding compositions became test specimens sprayed and subjected to the following tests:

• - Fire test on specimens of thickness 1.6 mm after UL 94,
• Notched impact strength according to DIN 53 543 (ak 260 ° C),
• Heat resistance according to Vicat B according to DIN 53 460 (Vicat) exam BRT 1.6 VO ak 260 ° C 23.7 (kJ / m²) Vicat 141 (° C)

2 B)

• Second Recipe is composed like Recipe 1, only that the bisphenol A homopolycarbonate a realtive Viscosity of 1.32 has.

The resulting molding compositions became test specimens sprayed and subjected to the following tests:

• - Fire test on specimens of thickness 1.6 mm after UL 94
• Notched impact strength according to DIN 53 543 (ak 260 ° C)
• Heat resistance according to Vicat B according to DIN 53 460 (Vicat) exam BRT 1.6 VO ak 260 ° C 46.5 (kJ / m²) Vicat 145 (° C)

In the case of physical data, the standard becomes small bars sprayed at 260 ° C melt temperature. The Be Drawing ak 260 ° C is the abbreviation for it.

Claims (5)

1. Mixtures consisting of

• a) 1 to 12 parts by weight BPO ₄ ,
• b) 0.05 to 1 part by weight of an aromatic Alkalisulfonats and
• c) 0.04 to 1 part by weight of a tetrafluoroethylene polymer wherein the components a), b) and c) are given by weight parts in any relative Ge weight ratio can be combined.

2. Mixtures according to claim 1, consisting of

• a) 2 to 10 parts by weight,
• b) 0.1 to 0.8 parts by weight and
• c) 0.08 to 1 part by weight.

3. Use of the mixtures of claims 1 and 2 as Flame retardant for thermoplastic, aroma tables, halogen-free, sulfur-free and phosphorus free polycarbonates. 4. Process for incorporating the mixtures of An claims 1 and 2 in thermoplastic, aromatic, halogen-free, sulfur-free and phosphorus-free poly Carbonates, characterized in that the he mixtures according to the invention the thermoplastic Polycarbonates via twin-screw extruder  or in internal kneaders at temperatures between 200 ° C and 350 ° C in amounts of 0.04 wt .-% to 12 Wt .-%, each based on 100 wt .-% polycarbonate incorporated. 5. Polycarbonate molding compounds, obtainable by the Ver driving of claim 4.