DE4100200A1 - Thermoplastic polycarbonate(s) - useful as a source of carbon di:oxide blowing agent for prodn. of thermoplastic polycarbonate foam - Google Patents

Abstract

Thermoplastic polycarbonates (I) are useful for foaming thermoplastic polycarbonates. Also claimed is a process for the prodn. of polycarbonate foam prods., by mixing (I) (with Mw = 5000-50,000) with 0.01-1 mol. % transesterification catalysts and 0.1-5 mol. % aromatic polycarboxylic acids and/or 0.1-5 mol. % water and opt. with 0.1-5 mol.% aliphatic hydroxycarboxylic acids and/or aliphatic alcohols (w.r.t. mols. of carbonate units of formula -O-R-O-CO- (with R = diphenolate residuel, and injection moulding or extruding this mixt. at 210-340 deg. C, with reaction times of 0.5-5 mins. Foam prods. (II) obtd. by this process are also claimed as such. Specifically the above process is carried out with addn. of normal additive(s); additive-contg. polycarbonate foam prods. (II) are also claimed. USE/ADVANTAGE - Foam prods. (II) are useful, eg. for the prodn.of lamp covers, housings, office equipment, parts of cabinets, etc. The invention enables the prodn. of thermoplastic polycarbonate foam by using, as blowing agent, the CO2 produced by controlled partial decompsn. of (I); the prods. (II) have a light colour, uniformly fine pore structure and smooth surfac

Description

The present invention relates to the use of thermoplastic polycarbonates for foaming thermoplastic polycarbonates.

The foaming of polycarbonates is known, whereby preferred blowing agents are those which are inert Eliminate gas such as nitrogen or carbon dioxide (see for example DE-AS 10 31 507 and DE-OS 24 34 085).

The use of oxalic acid is also known Blowing agent (see US Pat. No. 3,277,029).

It is surprisingly possible to use polycarbonates themselves to foam polycarbonates if CO _{2 is} released by controlled, partial degradation of the polycarbonate and this is used to foam the remaining polycarbonate.

The controlled degradation of the polycarbonate is carried out by adding transesterification catalysts in combination with aromatic polycarboxylic acids and / or with H ₂ O, where when using H ₂ O without aromatic polycarbonates, aliphatic hydroxycarboxylic acids and / or aliphatic alcohols with the addition of H ₂ O can be combined.

The degradation of polycarbonates with the release of CO ₂ under the influence of acids is known (see DE-AS 12 60 479), also in combination with catalysts (see EP-01 27 842 and US-PS 43 38 422).

But it is also known to add polycarbonates of acids to stabilize against the action kung moisture (see US-PS 39 51 903) and against radiation (EP-03 53 776).

The addition of fatty acids as mold release agents for Polycarbonate is also known (see U.S. Patent 44 09 351 and US-PS 44 08 000). However, this occurs also degradation of the polycarbonate (see DE-OS 37 04 666, Comparative Example 2 and Jp-Sho 47-41 092).

EP-A-01 58 212 describes the use of mono- and Citric acid diesters for making art fabric foam; as plastics are also polycarbonates thinks.

Thermoplastic aromatic polycarbonates in the sense of The present invention are polycarbonates which according to the  usual methods known in the literature from Di phenols and carbonate donors have been produced (see for example H. Schnell, Chemistry and Physics of Polycarbonates, Interscience Publishers, New York, 1964 '', U.S. Patent 30 28 365 and DE-OS 38 32 396.

Diphenols for such polycarbonates can, for example Hydroquinone, resorcinol, dihydroxybiphenyls, bis (hydroxy phenyl) alkanes, bis (hydroxyphenyl) cycloalkanes, bis (hydroxyphenyl) sulfide, bis (hydroxyphenyl) ether, bis (hydroxyphenyl) ketones, bis (hydroxyphenyl) sulfones, Bis (hydroxyphenyl) sulfoxides, α, α′-bis (hydroxyphenyl) diisopropylbenzenes, as well as their core alkylated and core halogenated compounds.

Preferred diphenols are, for example, 4,4'-dihydroxy biphenyl, 2,2-bis (4-hydroxyphenyl) propane, 2,4-bis (4- hydroxyphenyl) -2-methylbutane, 1,1-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-di methyl-4-hydroxyphenyl) propane, bis- (3,5-dimethyl-4- hydroxyphenyl) sulfone, 2,4-bis (3,5-dimethyl-4-hydroxy phenyl) -2-methylbutane, 1,1-bis (3,5-dimethyl-4-hydroxy phenyl) -p-diisopropylbenzene, 2,2-bis- (3,5-dichloro-4- hydroxyphenyl) propane, 2,2-bis (3,5-dibromo-4-hydroxy phenyl) propane and 1,1-bis (4-hydroxyphenyl) -3,3,5-tri methylcyclohexane.  

Particularly preferred diphenols 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-hydroxy phenyl) propane, 2,2-bis (3,5-dibromo-4-hydroxyphenyl) - propane, 1,1-bis (4-hydroxyphenyl) cyclohexane and 1,1- Bis- (4-hydroxyphenyl) -3,3,5-trimethylcyclohexane.

The diphenols can be used alone or in a mixture used with each other, so it is both homo polycarbonates and copolycarbonates included. The Diphenols are known from the literature or according to the literature known methods can be produced.

Small amounts, preferably amounts between 0.05 and 2.0 mol%, based on the moles of diphenols used, of tri- or more than trifunctional compounds, in particular those having three or more than three phenolic hydroxyl groups, can also be used will. Some of the compounds that can be used with three or more than three phenolic hydroxyl groups are, for example
Phloroglucin,
4,6-dimethyl-2,4,6-tri- (4-hydroxyphenyl) -hepten-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'-methyl-benzyl) -4-methylphenol,
2- (4-hydroxyphenyl) -2- (3,4-dihydroxyphenyl) propane,
Hexa- (4- (4-hydroxyphenyl-isopropyl) phenyl) orthotere phthalic acid ester,
Tetra- (4-hydroxyphenyl) methane,
Tetra- (4- (4-hydroxyphenyl-isopropyl) phenoxy) methane and
1,4-bis (4 ', 4''- dihydroxytriphenyl) methyl benzene.

Other possible branching agents are 2,4-dihydroxybenzoe acid, trimesic acid, cyanuric chloride and 3,3-bis- (3- methyl-4-hydroxyphenyl) -2-oxo-2,3-dihydroindole.

The 0.05 to 2 mol% optionally to be used, based on diphenols used, on branching can either with the diphenols themselves and the Molecular Ge weight regulators in the aqueous alkaline phase be placed, or in an organic solvent dissolved before phosgenation, are added.

Suitable molecular weight regulators are the known preferably monophenols.

The aromatic polycarbonates according to the present Er invention should weight average molecular weights w (determined by gel permeation chromatography) between 5000 and 50,000, preferably between 15,000 and 35,000 to have.  

The solution viscosities are accordingly between 1.15 and 1.35, measured in dichloromethane (0.5 g / 100 ml) Thermoplastic, aromatic polycarbonates in the sense of present invention include thermoplastic aromatic polyester carbonates with one, that is "Polycarbonates", in which a part, at most 50 mol% Carbonate structural units through aromatic dicarboxy lat structure units are replaced in a known manner.

Suitable aromatic dicarboxylic acids are, for example Orthophthalic acid, terephthalic acid, isophthalic acid, tert-butylisophthalic acid, 3,3'-diphenyldicarboxylic acid, 4,4'-diphenyldicarboxylic acid, 4,4'-diphenyletherdicarbon acid, 4,4'-benzophenone dicarboxylic acid, 3,4'-benzophenone dicarboxylic acid, 4,4'-diphenylsulfone dicarboxylic acid, 2,2- Bis (4-carboxyphenyl) propane, trimethyl-3-phenylindane 4,5′-dicarboxylic acid.

Of the aromatic dicarboxylic acids are particularly be prefers the terephthalic acid and / or isophthalic acid set.

Suitable diphenols are those for the poly above called carbonate production.

The same applies to the branches and to the mono phenolic chain terminator, but here too aromatic monocarboxylic acids, for example in the form their acid chlorides or esters can be used.  

The carbonic acid can be incorporated into the polyester carbonates either via COCl ₂ or via diphenyl carbonate, depending on the choice of the production process, that is, depending on whether phase interface polycondensation or melt transesterification is used to produce polyester carbonate.

The same applies to the aromatic dicarboxylic acids; they are either called aromatic dicarboxylic acid di chloride in the two-phase interfacial process or as Dicarboxylic acid diester in the melt transesterification process used. The same applies if chain as breaker monocarboxylic acids are used.

The preparation of those to be used according to the invention Polyester carbonates are made according to known manufacturing proceed, as already mentioned, for example the phase interface method or after melting transesterification process.

The polyester carbonates to be used can thus branched both linearly and in a known manner be.

The aromatic polyester carbonates have medium Weight average molecular weights w (determined by Gel permeation chromatography) between 5000 and 50 000, preferably between 15,000 and 35,000.  

The molar amount of carbonate units to aromatic dicarboxylate units in the polyester carbonates to be used according to the invention is at least 50:50, preferably 75:25 and in particular 90:10. In other words, the polyester carbonates to be used according to the invention are overweight the carbonate structural units, as the CO ₂ resource ce.

Transesterification catalysts which are suitable according to the invention are all for the transesterification of carbonic acid esters or Carboxylic acid esters known compounds, such as metal oxides, metal hydroxides, metal alkoxides, carboxylic acid connections of metals or organometallic compounds, but also 5-membered nitrogen-containing heterocycles, Amidines, tertiary amines and their salts and tetra alkyl ammonium hydroxides.

Suitable metals are those of the first major and minor group, the second main and sub-group, the third Main group, the fourth main and subgroup, the fifth main group, the sixth subgroup and the seventh and eighth subgroups.

Preferred transesterification catalysts are dibutyltin oxide, dibutyltin dilaurate, SnO _2nd , MgO, CaO, Ca (OH) _2nd , Tetrabutoxyorthotitanate, zinc acetate, diazabicycloun decene, diazabicyclonones, DABCO, imidazole, tetramethyl ammonium hydroxide, sodium hydroxide, potassium hydroxide, benzimidazole, ammonia, piperazine lead acetate, PbO, Sb _2nd O _3rd , Iron acetylacetonate, cobalt acetate and triethylammonium chloride.

The transesterification catalysts are used in amounts of 0.01 Mol% to 1 mol%, based on molar, aromatic Carbonate structure unit

foaming the the polycarbonate used. Preferred molar amounts Transesterification catalysts are 0.04-0.1 mol%.

The rest -O-R-O- is the rest of a dipheno lats.

Suitable aromatic polycarboxylic acids are in particular aromatic tricarboxylic acids, especially those whose Carboxyl groups do not form a 5-ring or 6-ring dianhydrids are capable.

Suitable polycarboxylic acids are, for example, trimesine acid, isophthalic acid, terephthalic acid, 3,3'-, 4,4'-or 3,3'-diphenyl ether dicarboxylic acid, 2,6-naphthalene di carboxylic acid, trimellitic acid, 1,4,5,8-naphthalene tetra carboxylic acid, 3,3 ′, 4,4′-benzophenonetetracarboxylic acid, 2,2 ', 4,4'-diphenylsulfonetetracarboxylic acid, phthalic acid and 2,2 ', 4,4'-diphenyl ether tetracarboxylic acid, but also aromatic hydroxypolycarboxylic acids such as 3- or 4-Hy  droxyphthalic acid, hydroxy terephthalic acid and 2,5-dihy droxyterephthalic acid. The preferred polycarboxylic acid is Trimesic acid.

The aromatic polycarboxylic acids are used in quantities of 0.1 mol% to 5 mol%, preferably from 0.5 mol% to 2 mol%, based again on molar aromatic car bonat structure unit

of the foam to be foamed Polycarbonate used.

Suitable hydroxycarboxylic acids are citric acid and their mono- or dialkyl esters, glyoxylic acid, lactic acid, ε-hydroxycaproic acid, γ-hydroxybutyric acid, malic acid or tartaric acid.

They are preferred in amounts of 0.1 mol% to 2 mol% as 0.2 mol% to 1 mol%, based again on molar, aromatic carbonate structural unit

of the polycarbonate to be foamed used.

Suitable aliphatic alcohols are aliphatic di-, Tri-, tetra-alcohols and aliphatic alcohols with more as 4 alcoholic OH groups.  

Suitable aliphatic alcohols are, for example Ethylene glycol, butanediol, propylene glycol, Aidpol, Gly cerin, trimethylolpropane, neopentyl glycol, pentaery thritol, mannitol and sorbitol, and polymeric alcohols such as Polyethylene glycol, polytetrahydrofuran and polypropylene glycol with preferably an Mn of less than 5000, where n in a known manner by determining the OH end group pen is determined.

Preferred alcohol is pentaerythritol.

The aliphatic alcohols are used in amounts of 0.1 Mol% to 5 mol%, preferably in amounts of 0.2 mol% up to 2 mol%, based again on molar, aromatic car bonat structural units

of the polycarbonate to be foamed used.

The amount of water is 0.1 mol% to 5 mol%, preferably example, 0.2 mol% to 2 mol%, based on mole aroma tables carbonate structural units

The incorporation of the transesterification catalysts in combination with the aromatic polycarboxylic acids and / or with H ₂ O, optionally with the use of aliphatic hydroxycarboxylic acids and / or aliphatic alcohols, is carried out in suitable mixers at temperatures from 220 ° C. to 320 ° C., preferably from 240 ° C.

Thereafter, the respective mixture by injection molding z. B. at 260 ° C to 340 ° C, or their extrusion z. B. at 210 ° C. up to 270 ° C can be processed into foam moldings, whereby Response times of 0.5 minutes to 5 minutes were observed will.

The polycarbonate foam mold obtained according to the invention bodies are characterized by their own light color, the same moderate fine foam structure, and smooth surface.

The present invention thus also relates to a process for the preparation of polycarbonate foam molded bodies, which is characterized in that thermoplastic polycarbonates having average weight average molecular weights w of 5000 to 50,000, preferably 15,000 to 35,000, with transesterification catalysts in amounts of 0 , 01 mol% to 1 mol%, in combination with aromatic polycarboxylic acids in amounts of 0.1 mol% to 5 mol% and / or in combination with H ₂ O in amounts of 0.1 mol% to 5 mol%, optionally with the use of aliphatic hydroxycarboxylic acids and / or of aliphatic alcohols in amounts of 0.1 mol% to 5 mol% based on moles in all cases. aromatic carbonate structural units

wherein -O-R-O-, a diphenolate residue, in mixed suitable mixers and then the obtained Mixing by injection molding or extrusion at temperatures from 210 ° C to  340 ° C processed into foam moldings, reaction times from 0.5 minutes to 5 minutes, preferably from 1 minute to 2 minutes are observed.

The present invention also relates to it polycarbonate foam mold available according to the invention body.

The foaming process according to the invention can still with the addition of those customary for foam production Additives such as reinforcing materials, such as glass fibers, and / or nucleating agents and / or flame protective agents, for example nonafluorobutane sulfone acid salts and / or mold release agents, for example Pentaerythritol tetrastearate and / or dyes and / or Pigments, for example rutile or carbon black, and / or Stabilizers against heat and UV radiation be performed.

The present invention thus also relates to Extension of the method according to the invention under one relation to one or more of these additives.

The present invention also relates to obtainable by this process according to the invention, Additive-containing molded polycarbonate foam.

The polycarbonate foam mold obtainable according to the invention Bodies can be used as molded parts for the production of large areas covers of lamps, housings, office equipment or used for the production of large cabinet elements will.

Examples (Addition of transesterification catalyst and aromatic Polycarboxylic acid) Example 1

The mixture is extruded, made from 87.45% branched bisphenol A polycarbonate, 10% of a mixture of polycarbonate with 30% short glass fiber (E-glass), 2% of a pigment mixture 07/394 made of TiO ₂ and carbon black, 5% trimesic acid and 0.05% dibutyltin oxide at 240/250/190 ° C in a three-zone single screw extruder. The extrusion is carried out on a three-zone single-screw extruder with a constant pitch increase of 1 D, screw diameter D = 37 mm, screw length L = 25 D, thread depth ratio (discharge zone / feed zone) 1: 2.5. The temperatures of the zones were 240 ° C, 250 ° C and 190 ° C. The foaming was carried out without calibration using the free foaming method. He holds a foam with a density of 0.8 g / cm ³ with a closed-cell, fine-pored structure.

Example 2

The mixture is extruded, made from 87.45% branched bisphenol A polycarbonate, 10% of a mixture of polycarbonate with 30% short glass fiber, 2% of a pigment mixture of TiO ₂ and carbon black, 0.5% trimesic acid and 0.05% magnesium stearate 240/250/190 ° C in a three-zone single screw extruder. The procedure is as described in Example 1 and a foam with a density of 0.4 g / cm ^{3 is obtained} .

Example 3

The mixture is extruded, made from 87.45% branched bisphenol A polycarbonate, 10% of a mixture of polycarbonate with 30% short glass fiber (E-glass), 2% of a pigment mixture of TiO ₂ and carbon black, 0.5% tri mesic acid and 0.05% trimesic acid diammonium salt, at 240/250/190 ° C in a three-zone single screw extruder. The procedure is as described in Example 1 and a foam with a density of 0.5 g / cm ^{3 is obtained} .

Example 4

The mixture is extruded, made from 87.45% branched bisphenol A polycarbonate, 10% of a mixture of polycarbonate with 30% short glass fiber (E-glass), 2% of a pigment mixture 07/394 made of TiO ₂ and carbon black, 0.5 % Trimesic acid and 0.05% piperazine at 240/250/190 ° C in a three-zone single-screw extruder. The procedure is as described in Example 1 and a foam with a density of 0.5 g / cm 3 is obtained.

Examples B (Addition of transesterification catalyst and H ₂ O) Example 5

The mixture is extruded 89.5% bisphenol A poly carbonate, 10% of a polycarbonate with 30% short glass fiber (E-glass), 0.49% water and 0.01% calcium oxide.

The extrusion takes place on a three-zone single screw extruder with constant 1 D gear increase, Screw diameter D = 37 mm, screw length L = 25 D, Gear ratio (discharge zone / feed zone) 1: 2.5.

The temperatures of the zones were 240 ° C, 250 ° C and 190 ° C. The foaming was carried out without calibration using the free foaming method. A closed-cell foam with a density of 0.6 g / m ^{3 was kept} .

Example C (Addition of transesterification catalyst, aromatic polycarboxylic acid and H ₂ O) Example 6

The mixture is extruded from 87.35% branched bisphenol A polycarbonate, 10% of a mixture of polycarbonate with 30% short glass fiber (E-glass), 2% of a pigment mixture of carbon black and TiO ₂ , 0.05% dibutyltin oxide , 0.5% trimesic acid and 0.1% water. The procedure is as described in Example 1 and a foam with a density of 0.5 g / cm 3 is obtained.

Example D (Addition of transesterification catalyst, H ₂ O and aliphatic hydroxycarboxylic acids) Example 7

The mixture is extruded from 87.5% branched bisphenol A polycarbonate, 10% of a mixture of polycarbonate with 30% short glass fiber (E-glass), 2% of a pigment mixture 07/394 made of TiO ₂ and carbon black, 0.5 % Trimesic acid (mixture of TiO ₂ and carbon black), 0.4% water, 0.01% calcium oxide and 0.09% citric acid butyl ester from Boeringer-Ingelheim. The extrusion takes place as in example 5. A foam with a density of 0.5 g / cm ^{3 is obtained} .

Example E (Addition of transesterification catalyst, H ₂ O and aliphatic alcohol)

The mixture is extruded from 87% branched bisphenol A polycarbonate, 10% of a mixture of Makrolon with 30% short glass fiber (E-glass), 2% of a pigment mixture of TiO ₂ and carbon black, 0.5% pentaerythritol, 0.4 % Water and 0.1% dibutyltin oxide and proceeded as described in Example 1 be. A foam with a density of 0.5 g / cm ^{3 is obtained} .

Claims (5)

1. Use of thermoplastic polycarbonates for Foaming of thermoplastic polycarbonates. 2. Process for the production of polycarbonate foam moldings, characterized in that ther moplastic polycarbonates with average weight average molecular weights w from 5000 to 50 000 with transesterification catalysts in amounts of 0.01 mol% to 1 mol%, in combination with aromatic polycarboxylic acids in Amounts from 0.1 mol% to 5 mol% and / or in combination with H ₂ O in amounts from 0.1 mol% to 5 mol%, optionally with the use of aliphatic hydroxycarboxylic acids and / or aliphatic alcohols in amounts of 0.1 mol% to 5 mol% based on moles, aromatic carbonate structural units in all cases wherein -ORO- is a diphenolate residue, mixed in suitable mixers at temperatures and then the mixture obtained by injection molding or extrusion at temperatures of 210 ° C to 340 ° C to foam bodies, with reaction times of 0.5 minutes to 5 minutes are observed . 3. Polycarbonate foam molded body, available after The method of claim 2. 4. The method according to claim 2, characterized in that that include one or more common additives will. 5. Additive-containing polycarbonate foam molded body obtainable by the method of claim 4.