DE1794053A1 - Thermoplastic molding compounds based on polycarbonates - Google Patents

Description

FARBENFABRIKEN BAYER AG LEVEIlKU S EN-B.yenwk 2 9. AU0. 1968 L / Hg Meet-AbwUueg

Thermoplastic molding compounds based on polycarbonates

It has been found that thermoplastic molding compositions with particularly advantageous properties are obtained when monomeric Polymerized vinyl compounds in the presence of thermoplastic polycarbonates based on dihydroxydiaryl compounds.

Polycarbonates which are prepared in a known manner by reaction of dihydroxydiaryl compounds are suitable for carrying out the process with phosgene in solution or suspension or according to the transesterification process, for example with diphenyl carbonate, have been produced (see German patents 971 777 * 971 79o, 959 ^ 97, 1 007 996, 1 oll 148). Preferred polycarbonates are the polycarbonates from di-monohydroxyaryl-alkanes, in particular Polycarbonates from 2,2- (4,4'-dihydroxydiphenyl) propane. Examples of other suitable polycarbonates of the di- (monohydroxyphenyl) -substituted aliphatic or cycloaliphatic hydrocarbons are 1, l- (4,4'-dihydroxydiphenyl) -cyclohexanes, in which

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both hydroxyphenyl groups are on the same carbon atom »as well as Mixed condensates from the bisphenols mentioned. The polycarbonates can furthermore by incorporation of dihydroxy compounds, the in addition to the two hydroxyl groups, additional reactive ones 3 groups, such as carboxyl groups and hydroxyl groups, contain «modified.

The molecular weight of the thermoplastic polycarbonate is preferably between about Ιο, οοο and about 7o, ooo, in particular between about 20,000 and 50,000.

Suitable monomeric vinyl compounds are alkenyl aromatic Compounds that are preferably la mixture old acrylonitrile disgusting substituted acrylonitriles are used. Among alltenyl aromatic compounds are compounds of the following understood general formula:

H = CH ₂

in which:

R ^f = hydrogen, methyl or ethyl; R "= halogen, the hydroxyl group or a lower one

Alkyl radical with 1-4 carbon atoms, which is generally in o ~ or ρ-position to the alkenyl group.

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As typical representatives of these alkenyl aromatic compounds;

examples include: styrene, ot-methylstyrene, o- or p-chlorostyrene and isopropenylphenol. Mixtures of styrene and / or Λ-methylstyrene with acrylonitrile are particularly suitable, the acrylonitrile generally being used in amounts of about 10 to 40 percent by weight, preferably about 15 to 10 percent by weight, based on total monomers. The monomers are generally used in amounts of about 0.5-2% by weight, preferably about ^K -15% by weight, based on the total weight of monomers and polycarbonates.

The polymerization of the monomers is generally carried out in an organic solvent in which the polycarbonate is dissolved, with the action of polymerization initiators and optionally molecular weight regulators at temperatures of about 40 ° -12 ° C., preferably under an inert gas atmosphere. Suitable solvents for polycarbonates are all solvents which do not have an inhibiting effect, for example methylene chloride, chloroform or chlorobenzene. As polymerization initiators are all in polymerizations in solution which are customary compounds such as azo, peroxide, or _f peroxydicarbonate compounds in question. The solvents themselves or additionally mercaptans and xanthates can be used as molecular weight regulators.

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According to a preferred embodiment, the polymerization can the monomers are carried out directly in the solutions obtained in the production of the polycarbonates, so that special measures for isolating the polycarbonate are avoided here.

It is known from the German Auslegeschrift 1 Io9 884, thermoplastic molding compositions by mixing polycarbonates with polymers of alkenyl-aromatic compounds or copolymers to establish these connections. Compared to these known molding compositions, the molding compositions according to the invention stand out by higher transparency and higher resistance to alkalis, especially in the heat. With the refractometric Determination of the freezing temperature results from the invention Molding compounds, in contrast to the known molding compounds, have an intersection, from which in the case of the present molding compounds the Presence of a single phase can be closed. This unexpected result can possibly be explained by that during the polymerization graft polymers are formed which are responsible for the good tolerance and the formation of a uniform phase are responsible.

In the following examples the parts given are parts by weight.

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example 1

A) To a solution of 875 parts of bisphenol A polycarbonate with a rel. Viscosity of 1.3o, measured on a 0.5% solution in methylene chloride at 25 ° C., in 400 parts of chlorobenzene, 87.5 parts of styrene, 37.5 parts of acrylonitrile and 1.0 part of azodiisobutyronitrile (ADBN) are added. The mixture is stirred at 70 ° C. under nitrogen, supplemented after 5 hours by adding 1.0 part of ADBN and kept at 70 ° C. for a further 10 hours. After removing the solvent, a product remains with a rel. Viscosity of 1.292 (measured as a 0.5% solution in chloroform at 20 ° C.), which, cast as a film from 20% methylene chloride solution, is almost transparent. The haze is 2.6 % Hazen, measured with a Hardy spectrograph according to ASTM D I003-59 T, the elongation at break 124 % and the melt viscosity at 280 ° C. 3.77 × ^{10 5} poise.

B) Verg ichsv le ers uch

450 parts of the same polycarbonate and 5o parts of a copolymer made from 70 percent by weight styrene and 3 percent by weight acrylonitrile, with a rel. Viscosity of 1.71 are dissolved in 1200 parts of methylene chloride. Although both polymers give clear solutions on their own, the mixture is very cloudy. A film produced therefrom has, as measured in Example A, a haze of 60.5 % Hazen, the elongation at break is 61 %, the melt viscosity is 2, Io lo ^ poise.

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While a PIn produced according to Example B is completely degraded after 3 hours by lo ^ ige sodium hydroxide solution at 100 ° C , the weight loss of a film produced according to Example A is only about 15 %.

Example 2

According to Example 1 A, in the presence of a solution of 875 parts of a polycarbonate of 50 mol percent 2, hydroxydiphenyl) propane and 50 mol percent!,! - (^, V diphenyl) cyclohexane with a rel. Viscosity of 1.295 in 3,000 parts of chlorobensol, 117 parts of styrene and 33 parts of acrylonitrile, copolymerized and worked up, a uniform product also being formed. c.

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Claims (1)

Patent claims 1. Process for the production of thermoplastic molding compositions from polycarbonates based on dihydroxydiaryl compounds, In particular dihydroxydiphenylalkanes, characterized in that vinyl monomers in the presence of the thermoplastic Carbonates, preferably in solution, polymerized. 2. The method according to claim 1, characterized in that one daduareh as vinyl monomers alkenyl-aromatic compounds, preferably in a mixture with acrylonitrile, 3 · The method according to claim 2, characterized in that one 2 '' Mixtures of styrene and / or OK methyls> 1 old acrylonitrile are used, the acrylonitrile being used in amounts of 10 to 40 percent by weight, preferably 15 to 30 percent by weight, based on the total weight of the monomers. * 4-, method according to claims 1-3 »characterized in that that the monomers are used in amounts of 0.5-2o percent by weight, preferably 5-15 percent by weight, based on the total weight of polycarbonate and monomers. 5. Process according to Claims 1-4, characterized in that the solvent used is chlorobenzene. Le A 11 688 - 7 - 209816/1518