EP1373398A1

EP1373398A1 - Use of zwitterionic compounds as mold-release agents in thermoplastic materials

Info

Publication number: EP1373398A1
Application number: EP02706756A
Authority: EP
Inventors: Martin Döbler; Walter Köhler; Siegfried Neumann; Wolfgang Ebert
Original assignee: Bayer AG
Current assignee: Covestro Deutschland AG
Priority date: 2001-03-19
Filing date: 2002-03-06
Publication date: 2004-01-02
Also published as: CN1498247A; TWI299343B; KR100846287B1; US20020173567A1; HK1066020A1; CN1244622C; US6737457B2; WO2002074848A1; JP2004530744A; DE10113168A1; JP4204323B2; KR20030086608A

Abstract

The invention relates to the use of zwitterionic compounds as mold-release agents in thermoplastic materials, and to thermoplastic molding compounds provided therewith that have good mold-release properties, as well as to molded articles produced from said molding compounds.

Description

Use of zwitterionic compounds as mold release agents in thermoplastics.

The present invention relates to the use of zwitterionic

Compounds as mold release agents in thermoplastics, well-equipped thermoplastic molding compounds equipped therewith, as well as molded parts made from these molding compounds.

Patents and publications which describe the demoulding effect of various additives in thermoplastics in general and in particular polycarbonate are known. The most common substances used as mold release agents are the esters of long-chain aliphatic acids and alcohols. Examples include the use of esters from fatty acid alcohols or polyols, such as. B. pentaerythritol, with fatty acids as described in DE-A 33 12 158, EP-A 100 918, EP-A 103 107, EP-A 561 629, EP-A 352 458, EP-A 436 117 are or from esters of Guerbet alcohols in US Pat. No. 5,001,180, DE-A 3,312,157, US Pat. No. 5,744,626 or the montanic acids as acid component in US Pat. No. 4,097,435. It is disadvantageous that the fatty acid esters are only available in quantities of more than 0.5% by weight show a clear demolding effect. However, these concentrations often lead to turbidity and / or formation of mold deposits. Siloxanes, which are also known as mold release agents (cf. US Pat. No. 4,536,590, US Pat. No. 4,390,651, US Pat. No. 3,751,519), are poorly compatible with polycarbonate and lead to clouding in the concentrations required for effectiveness. α-olefin polymers (EP-A 561 630, EP A 230 015) with remaining double bonds (DE-A 32 44 499) are not color-stable. With hydrogenated systems, as with the long-chain alkanes (US Pat. No. 4,415,696), there is also a compatibility problem with polycarbonate, and the waxy, often partly liquid, partly waxy, consistency of these products is a hindrance. From US-A 4 927 911, zwitterionic compounds are known as polymerization catalysts. However, nothing is said about their suitability as mold release agents.

Furthermore, for example from JP-A 62 109 854 or DE-A 2409412 an antistatic effect of zwitterionic compounds is also described in combination with other surface-active compounds. However, a possible suitability as a mold release agent has not been disclosed.

Starting from the prior art, the task was therefore to find more effective mold release agents which are effective in low concentrations, do not form mold deposits and do not lead to clouding or discolouration in the effective concentrations, and thus make available a good mold release compound which, in addition to excellent Demolding properties and transparency have sufficient temperature stability without discoloration or transesterification.

The distortion-free demoulding of polycarbonate molded parts, while maintaining the very high-quality surface, is an ongoing challenge due to the demands for shorter cycle times and higher processing temperatures, with increasingly complex shapes.

The task was solved by using amphoteric zwitterionic substances.

The present invention accordingly relates to the use of amphoteric zwitterionic substances as mold release agents in thermoplastic molding compositions. The present invention furthermore relates to molding compositions comprising:

90-99.995% by weight of a thermoplastic

0.005 to 5.0% by weight, preferably 0.001 to 2.0% by weight, very particularly preferably 0.01 to 1.0% by weight of a zwitterionic compound

The molding compositions according to the invention can also contain conventional additives such as e.g. Contain thermal stabilizers, UV stabilizers, other mold release agents, flame retardants, anti-dripping agents, fillers, glass fibers and blend partners such as ABS, SAN, EPDM or polyesters based on terephthalic acid and diols.

The molding compositions according to the invention can be contaminated with impurities which contain the individual constituents of the molding composition from their synthesis, processing, processing and storage, as well as contaminations which originate from the production or processing processes of the molding compositions according to the invention. However, the goal is to get the cleanest products possible.

Molded parts containing the molding compositions according to the invention are also the subject of the present application.

The term zwitterionic compounds in the sense of the invention generally refers to compounds which carry at least one positive and at least one negative charge on a charge center (for example one atom / group of atoms) within a molecule. The charge centers are therefore linked together by covalent bonds.

Compounds of the formula (I) are preferred:

In which

• R 1, R ₂ , R ₃ = alkyl, aryl, alkaryl, aralkyl radical with 1-30 C atoms, unsubstituted or fully or partially chlorinated or fluorinated and optionally also branched, preferably phenyl, unbranched unsubstituted alkyl radicals with 1 Is -20 C atoms, particularly preferably methyl and / or alkyl having 12-20 C atoms or phenyl,

P = bivalent alkylene radical with 1-30 C atoms, unsubstituted or fully or partially chlorinated or fluorinated and optionally also branched, preferably unbranched unsubstituted α, α-alkylene radical C ₁ -C ₅ ,

Y = nitrogen or phosphorus, preferably nitrogen,

X = -SO ₃ ^" , -COO ^" , PO ₃ ^" , preferably -SO ₃ ^' .

Particularly preferred are sulfobetaines (X - is -SO ₃ ^"and Y = nitrogen), in which at least one of the radicals R _ls R _2, R ₃ is a linear alkyl radical having from 12 to

20 carbon atoms, the remaining radicals are methyl radicals and j is an alkyl radical with 2-5 carbon atoms.

Is very particularly preferably N, N-dimethyl-N-stearyl-N- (3-sulfopropyl) -ammo- minium betaine (Ralufon ^® DS, Raschig AG, Ludwigshafen, Germany).

The zwitterionic substances according to the invention are commercially available and can be obtained from the chemical trade. Thermoplastics in the sense of the invention mean the polymers of ethylenically unsaturated monomers and / or polycondensates of bifunctional reactive compounds. Mixtures of several plastics are also possible.

Particularly suitable thermoplastics are polycarbonates or copolycarbonates

Basis of diphenols, poly- or copolyacrylates and poly- or copolymethacrylates such as exemplarily and preferably polymethyl methacrylate, poly- or copolymers with styrene such as exemplarily and preferably transparent polystyrene or polystyrene-acrylonitrile (SAN), transparent thermoplastic polyurethanes, as well as polyolefins such as exemplarily and preferably transparent types of polypropylene or

Polyolefins based on cyclic olefins (eg TOPAS ^® , Ticona), poly- or copolycondensates of terephthalic acid, such as, for example and preferably, poly- or copolyethylene terephthalate (PET or CoPET) or glycol-modified PET (PETG).

Thermoplastic, aromatic polycarbonates or copolycarbonates are particularly preferred.

Thermoplastic, aromatic polycarbonates in the sense of the present invention are both homopolycarbonates and copolycarbonates; the polycarbonates can be linear or branched in a known manner.

Some, up to 80 mol%, preferably from 20 mol% to 50 mol%, of the carbonate groups in the polycarbonates suitable according to the invention can be replaced by aromatic dicarboxylic acid ester groups. Such polycarbonates, which contain both acid residues of carbonic acid and acid residues of aromatic dicarboxylic acids built into the molecular chain, are, to be precise, aromatic polyester carbonates. For the sake of simplicity, they should be subsumed in the present application under the generic term of thermoplastic, aromatic polycarbonates. The polycarbonates to be used according to the invention are prepared in a known manner from diphenols, carbonic acid derivatives, optionally chain terminators and optionally branching agents, with some of the carbonic acid derivatives being replaced by aromatic dicarboxylic acids or derivatives of dicarboxylic acids to produce the polyester carbonates, depending on the conditions in the aromatic ones Polycarbonate carbonate structural units to be replaced by aromatic see dicarboxylic acid ester structural units.

Details of the manufacture of polycarbonates have been recorded in hundreds of patent documents for about 40 years. As an example, just look at

Schnell, Chemistry and Physics of Polycarbonates, Polymer Reviews, Volume 9, Interscience Publishers, New York, London, Sydney 1964;

• D.C. Prevorsek, B.T. Debona and Y. Kesten, Corporate Research Center, Allied Chemical Corporation, Morristown, New Jersey 07960: "Synthesis of

Poly (ester carbonate) copolymers "in Journal of Polymer Science, Polymer Chemistry Edition, Vol. 19, 75-90 (1980)";

• D. Freitag, U. Grigo, P.R. Müller, N. Nouvertne ', BAYER AG, "Polycarbonates" in Encyclopedia of Polymer Science and Engineering, Volume 11, Second Edition, 1988, pages 648-718 and finally

• Dres. U. Grigo, K. Kircher and P. R-Müller "Polycarbonate" in Becker / Braun, plastic manual, volume 3/1, polycarbonates, polyacetals, polyester, cellulose esters, Carl Hanser Verlag Munich, Vienna 1992, pages 117-299

directed.

The thermoplastic polycarbonates, including the thermoplastic, aromatic polyester carbonates, have average molecular weights Mw (determined by measuring the relative viscosity at 25 ° C. in CH ₂ C1 ₂ and a concentration of 0.5 g per 100 ml of CH ₂ C1 ₂ ) from 12,000 to 120,000, preferably from 15,000 to 80,000 and in particular from 16,000 to 50,000.

Diphenols suitable for the preparation of the polycarbonates to be used according to the invention are, for example, hydroquinone, resorcinol, dihydroxydiphenyl, bis (hydroxyphenyl) alkanes, bis (hydroxyphenyl) cycloalkanes, bis (hydroxyphenyl) sulfides, bis (hydroxyphenyl) ethers , Bis (hydroxyphenyl) ketones, bis (hydroxyphenyl) sulfones, bis (hydroxyphenyl) sulfoxides, (α, α'-bis (hydroxyphenyl) diisopropylbenzenes, and also their ring-alkylated and ring-halogenated compounds.

Preferred diphenols are 4,4'-dihydroxydiphenyl, 2,2-bis (4-hydroxyphenyl) -l-phenyl-propane, 1,1-bis (4-hydroxyphenyl) -phenyl-ethane, 2,2-bis- (4-hydroxyphenyl) propane, 2,4-bis (4-hydroxyphenyl) -2-methylbutane, 1,1-bis (4-hydroxyphenyl) -m / p diisopropylbenzene, 2,2-bis- (3-methyl-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, l, l-bis- (3,5-dimethyl -4-hydroxyphenyl) -m / p-diisopropyl-benzene, 2,2- and l, l-bis- (4-hydroxyphenyl) -3,3,5-trimethylcyclohexane.

Particularly preferred diphenols are 4,4'-dihydroxydiphenyl, l, l-bis (4-hydroxyphenyl) phenylethane, 2,2-bis (4-hydroxyphenyl) propane, 2,2-bis (3rd , 5-dimethyl-4-hydroxyphenyl) propane, 1, 1-bis (4-hydroxyphenyl) cyclohexane and l, l-bis (4-hydroxyphenyl) -3, 3, 5-trimethylcyclohexane.

These and other suitable diphenols are e.g. in U.S. Patents 3,028,635,

2 999 835, 3 148 172, 2 991 273, 3 271 367, 4 982 014 and 2 999 846, in German Offenlegungsschriften 1 570 703, 2 063 050, 2 036 052, 2 211 956 and

3,832,396, French Patent 1,561,518, in the monograph "H. Schnell, Chemistry and Physics of Polycarbonates, Interscience Publishers, New York 1964" and in Japanese Laid-Open Publications 62039/1986,

62040/1986 and 105550/1986. In the case of the homopolycarbonates, only one diphenol is used, in the case of the copolycarbonates, several diphenols are used, the bisphenols used, of course, as well as all the other chemicals and auxiliaries added to the synthesis with those from their own synthesis

Contaminants can be contaminated, although it is desirable to work with raw materials that are as clean as possible.

Suitable chain terminators are both monophenols and monocarboxylic acids. Suitable monophenols are phenol, alkylphenols such as cresols, p-tert-butylphenol, pn-octylphenol, p-iso-octylphenol, pn-nonylphenol and p-iso-nonylphenol, halophenols such as p-chlorophenol, 2,4-dichlorophenol, p-bromophenol , Cumylphenol and 2,4,6-Tribromphenol, or their mixtures.

Suitable monocarboxylic acids are benzoic acid, alkylbenzoic acids and halogenated benzoic acids.

Preferred chain terminators are the phenols of the formula (I)

R ^b - Ph— OH 0)

wherein

R ^{6 is} H or a branched or unbranched Ci-C ₁₈ alkyl radical and

Ph stands for a divalent aromatic radical with 6 to 18 carbon atoms, preferably phenylene.

The amount of chain terminator to be used is 0.5 mol% to 10 mol%, based on moles of diphenols used in each case. The chain terminators can be added before, during or after phosgenation. Suitable branching agents are the tri- or more than trifunctional compounds known in polycarbonate chemistry, in particular those with three or more than three phenolic OH groups.

Suitable branching agents 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- (2,4-dihydroxyphenyl) propane,

Hexa- (4- (4-hydroxyphenyl-isopropyl) phenyl) orthoterephthalic acid ester, tetra- (4-hydroxyphenyl) methane, tetra- (4- (4-hydroxy-phenyl-isopropyl) phenoxy) methane and 1,4 -Bis [(4 ', 4 "-dihydroxy-triphenyl) -methyl] -benzene as well as 2,4-dihydroxybenzoic acid, trimesic acid, cyanuric chloride and 3,3-bis- (3-methyl-4-hydroxyphenyl) -2- oxo-2,3-dihydroindole.

The amount of branching agents which may be used is 0.05 mol% to 2.5 mol%, based in turn on moles of diphenols used in each case.

The branching agents can either be introduced with the diphenols and the chain terminators in the aqueous alkaline phase, or added dissolved in an organic solvent before the phosgenation.

All of these measures for the production of the polycarbonates are familiar to the person skilled in the art.

Aromatic dicarboxylic acids suitable for the production of the polyester carbonates are, for example, phthalic acid, terephthalic acid, isophthalic acid, tert-butylisophthalic acid, S ^ '- diphenyldicarboxylic acid, 4,4'-diphenyldicarboxylic acid, 4,4-

Benzophenone dicarboxylic acid, 3, 4'-benzophenone dicarboxylic acid, 4,4'-diphenyl ether dicarboxylic acid, 4,4'-diphenylsulfone dicarboxylic acid, 2,2-bis (4-carboxyphenyl) propane, trimethyl-3-phenylindane-4,5'-dicarboxylic acid, or mixtures thereof.

Of the aromatic dicarboxylic acids, terephthalic acid and / or isophthalic acid are particularly preferably used.

Derivatives of the dicarboxylic acids are the dicarboxylic acid dihalides and the dicarboxylic acid dialkyl esters, in particular the dicarboxylic acid dichlorides and the dicarboxylic acid dimethyl esters and dicarboxylic acid diphenyl esters.

The carbonate groups are replaced by the aromatic dicarboxylic acid ester groups essentially stoichiometrically and also quantitatively, so that the molar ratio of the reactants is also found in the finished polyester carbonate. The aromatic dicarboxylic acid ester groups can be incorporated either statistically or in blocks.

Preferred methods of producing the polycarbonates to be used according to the invention, including the polyester carbonates, are the known interfacial process and the known melt transesterification process.

In the first case, phosgene is preferably used as the carbonic acid derivative, in the latter case preferably diphenyl carbonate. Catalysts, solvents, work-up, reaction conditions etc. for the production of polycarbonate are sufficiently described and known in both cases.

The molding compositions according to the invention can be prepared by adding the amphoteric zwitterionic compounds according to the invention into the melt during synthesis or, in the case of the phase interface process, in a work-up or concentration step, but also in solution or melt of the finished thermoplastic. In the case of a solution, this is done by

Dissolves thermoplastics in a suitable solvent with the inventive amphoteric zwitterionic compounds and, if appropriate, simultaneously or successively further additives are added, the solvent is then evaporated off and the mixture obtained is granulated. In the melt, this is done by optionally mixing the thermoplastics with the amphoteric zwitterionic compounds according to the invention either simultaneously or successively with other additives, either in bulk or in solution, and then the mixtures either at temperatures between 260 ° C. and 360 ° C. melt compounded or melt extruded at temperatures between 250 ° C and 320 ° C, and the mixture obtained granulated.

To achieve improved plastic molding compositions, it is also possible for at least one additional additive usually present in thermoplastic materials, preferably poly- and copolycarbonates, such as e.g. Stabilizers (as described, for example, in EP A 0 839 623 AI or EP A 0 500 496 AI), especially thermal stabilizers, especially organic hindered ones

Phenols, hindered amines (HALS), phosphites or phosphines, by way of example and preferably triphenylphosphine, further known mold release agents, by way of example and preferably fatty acid esters of glycerol or tetramethanolmethane, where unsaturated fatty acid can also be completely or partially epoxidized, in particular glycerol monostearate (GMS) or pentaerythritol tetrastearate (PET ), Flame retardants, antistatic agents, UV absorbers, for example and preferably hydroxy-benzotriazoles and hydroxytriazines, fillers, glass fibers, foaming agents, dyes, pigments, optical brighteners, transesterification catalysts and nucleating agents or the like preferably incorporated in amounts of up to 5% by weight, preferably 0.01 to 5% by weight, based on the mixture as a whole, particularly preferably 0.01% by weight to 1% by weight, based on the amount of plastic becomes.

Suitable glass fibers are all commercially available types and types of glass fibers, i.e. cut glass types long glass fibers (chopped strands) and short glass (milled fibers), provided that they are compatible with suitable polycarbonate sizes. The glass fibers used to manufacture the molding compounds are made from E-glass. According to DIN 1259, e-glass is an aluminum-boron-silicate glass with an alkali oxide content of less than 1% by weight. Glass fibers with a diameter of 8 to 20 μm and a length of 3 to 6 mm (chopped strands) are usually used. Short glass (milled fibers) can also be used, as can suitable glass balls.

Flame retardants such as. B. find use in polycarbonate and can also be used in the molding compositions according to the invention are alkali salts of organic and inorganic acids, especially sulfonic acids such as

Sodium or potassium perfluorobutanesulfonate, potassium hexafluoroaluminate, sodium hexafluoroaluminate, potassium diphenylsulfone sulfonate, sodium 2-formylbenzenesulfonate, sodium (N-benzenesulfonyl) benzenesulfonamide, often in combination with other flame retardants, such as halogenated organic compounds , Cryolite and Teflon as well as tetrabromobisphenol oligocarbonate.

These conventional additives can be added in a known manner together with the components according to the invention or afterwards to the thermoplastics.

The molding compositions according to the invention can be processed to moldings on the customary processing machines by known methods under the processing parameters customary for polycarbonate. The invention therefore also relates to the parts produced from the molding compositions according to the invention, such as molded parts and semi-finished products.

The molded parts are used, for example, in the electrical, electronics, lighting, computer, construction, vehicle and / or aircraft sector.

The molding compositions are suitable for injection molding and extrusion articles, such as, for example, films, sheets, twin-wall sheets, lights, data carriers, such as compact discs or digital versatile discs, lights, housings for electrical appliances, computers or Motor vehicle equipment such as windows, dashboard parts, lenses, covers and the like or toys.

Examples

The amounts in the examples, expressed in% by weight, relate to the weight of the total mixture.

Polycarbonate 1:

An additive-free aromatic polycarbonate made from 2,2-bis (4-hydroxyρhenyl) propane with phenol end groups and a solution viscosity of 1.28. It is melted at 290 ° C on a twin-screw extruder (ZSK 32/2). The polymer strand was cooled and granulated.

Polycarbonate 2:

An additive-free aromatic polycarbonate made from 2,2-bis (4-hydroxyphenyl) propane with tert-butylphenol end groups with a solution viscosity of 1.195. It is melted at 280 ° C on a twin-screw extruder (ZSK 32/2). The polymer strand was cooled and granulated.

The granules were dried in a vacuum drying cabinet at 80 ° C. for 24 hours and injected into plate-shaped test specimens on an injection molding machine at 310 ° C. and a mold temperature of 110 ° C. wall temperature.

The coefficients of friction were measured using a specially made measuring tool. In all tests in an Arburg Allrounder 320-210-850-D injection molding machine, the same plate-shaped molded part was always injected at a mold temperature of 90 ° C at a melt temperature of 300 ° C. After cooling for 20 seconds, the molded part is rotated through an angle of 90 ° in the closed mold. A process data acquisition system measures the breakaway torque of the plate and the contact pressure of the tool stamp on the plate. The coefficients are determined from the measurement parameters. The coefficient of static and sliding friction is used as a measure of the release effect. Smaller values are therefore advantageous compared to high values.

Examples 1 to 4 and comparative examples 1 to 5 are listed in Table 1. As a comparison, a mold release-free polycarbonate, a product containing GMS = glycerol monostearate (Loxiol EP 129, Henkel KGaA, Düsseldorf, Germany) and a product containing PETS = pentaerythritol tetrastearate (Loxiol VPG 861, Henkel KGaA) were given.

The molding compositions according to the invention are distinguished by significantly smaller coefficients of friction and are already more effective in smaller quantities than the standard demoulders GMS and PETS.

Table 1:

Claims

claims

1. Use of zwitterionic compounds as mold release agents in thermoplastic molding compositions.

2. Molding compositions containing a thermoplastic and zwitterionic compounds according to claim 1 as mold release agents.

3. Molded parts containing molding compositions according to claim 2, in particular lamp covers, optical data storage media such as CD's, DVD's and their writable or rewritable further developments, plates, twin-wall sheets, headlight lens, glazing elements, apparatus housings such as computer housings and machine tool housings

4. Molded parts according to claim 3, characterized in that the used

Thermoplastic is polycarbonate.

5. Use according to claim 1, characterized in that zwitterionic compounds of the formula (I)

R ₁ R ₂ R ₃ -Y ⁺ -R ₄ -X ^' (I)

in which

R 1, R ₂ , R ₂ = alkyl radical having 1-30 C atoms, which can also be completely or partially chlorinated or fluorinated and, if appropriate, can also be branched, preferably an unbranched unsubstituted alkyl radical having 1-18 C atoms R = divalent alkylene radical with 1-30 C atoms, which can also be wholly or partly chlorinated or fluorinated and can optionally also be branched, preferably an unbranched unsubstituted α, α-alkylene radical C1-C5

Y = nitrogen or phosphorus

X = -so ₃ -, -COO-, PO ₃ ^"

means to be used.

6. Molding compositions according to claim 2, characterized in that they contain 90-99.995 wt .-% of a thermoplastic and 0.005 to 5.0 wt .-% of at least one zwitterionic compound.

7. Molding compositions according to claim 2, characterized in that they contain at least one zwitterionic compound of the formula (I),

in which

R 1, R ₂ , R ₂ = alkyl radical having 1-30 C atoms, which can also be fully or partially chlorinated or fluorinated and, if appropriate, can also be branched, preferably an unbranched unsubstituted

Alkyl radical with 1-18 C atoms

Rt = divalent alkylene radical with 1-30 C atoms, which can also be wholly or partly chlorinated or fluorinated and, if appropriate, can also be branched, preferably an unbranched, unsubstituted α, α-alkylene radical C1-C5 Y = nitrogen or phosphorus

X = -SO ₃ ^' , -COO-, PO ₃ ^"

means included.

8. Molding compositions according to claim 2, characterized in that they contain polycarbonate as thermoplastics.

9. Molding compositions according to claim 2, characterized in that they 90-

Contain 99.995% by weight of a thermoplastic and 0.005 to 5.0% by weight of at least one zwitterionic compound.