EP1228131A1

EP1228131A1 - Radio-opaque molded plastic parts

Info

Publication number: EP1228131A1
Application number: EP00960464A
Authority: EP
Inventors: Martin Döbler; Klaus Horn; Michael Prein; Siegfried Neumann; Walter Köhler
Original assignee: Bayer AG
Current assignee: Covestro Deutschland AG
Priority date: 1999-08-27
Filing date: 2000-08-16
Publication date: 2002-08-07
Also published as: NO20020732D0; CA2382954A1; BR0013546A; NO20020732L; CN1371405A; KR20020021814A; WO2001016225A1; IL147805A0; DE19940862A1; AU7276400A; JP2003508569A; HK1050021A1; MXPA02002040A

Abstract

The invention relates to the use of derivatives of the iodobenzoic acid for producing radio-opaque molded parts and to plastic materials, molded plastic materials and molded plastic bodies that contain at least one ester of the iodobenzoic acid.

Description

X-ray contrastable molded plastic parts

The application relates to the use of derivatives of iodobenzoic acid for the production of X-ray-controllable molded articles made of plastic and plastics,

Plastic molding compositions and plastic moldings containing at least one derivative of iodobenzoic acid.

For the medical sector and for children's toys, transparent plastic moldings with good mechanics are sought, which are used in X-ray examinations in the

Bodies can be detected. Furthermore, these materials should have sufficient light stability, at least for use in the interior of buildings.

Commercial moldings based on polycarbonates are unsuitable for this purpose because their contrast in the X-ray image is too low. For this reason, attempts have been made to add x-ray contrast media containing barium or bismuth to polycarbonates. However, these contrast agents are not sufficiently suitable for toxicological reasons and because of their effects which change the mechanical and optical properties of the commercially available polymers.

The use of iodine-containing compounds as described in US Pat. No. 3,469,704, DE-A-17 20 812, GB-A-11 63 816, US Pat. No. 3,382,207 and US Pat. No. 3,535,300 in molding compositions or moldings does not satisfy either the desired property profile for medical applications and toy parts. It has been shown, for example, that such molding compounds or molded parts turn reddish under room lighting after a few weeks and / or have poor mechanical properties and / or have too little thermal resistance and / or contain too little iodine in the X-ray image to be detectable. The object of the invention is therefore to provide X-ray contrast media which do not negatively influence the material properties of plastics.

It has now surprisingly been found that derivatives of iodobenzoic acids meet the desired profile of requirements. Even with small amounts of the iodo-benzoic acid derivatives, molded bodies can be produced that can be detected by means of X-rays

The present application therefore relates to the use of iodobenzoic acid derivatives as X-ray contrast media, in particular in plastics, in particular for transparent plastics, and also plastics, plastic molding compositions and plastic moldings containing at least one ester of iodobenzoic acid.

Derivatives of iodobenzoic acid according to the invention are amides, alkylamides, dialkylamides and in particular esters. Esters and amides which are prepared from mono- or polyhydric, aliphatic or aromatic alcohols or amines are preferred.

Aliphatic alcohols and amines are exemplary and preferably alcohols and amines having 1 to 30 carbon atoms. The carbon chain can be linear or branched. The carbon chain can contain one or more alcohol or amine functionalities, and the alcohol or amine functionality can be located anywhere in the carbon chain. Optionally, the alcohol can also be halogenated.

Esters based on methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, tert-butanol, 1-pentanol, 2-pentanol, 3-pentanol, 2-methyl-1-butanol are preferred. 2-methyl-2-butanol, 3-methyl-l-butanol, 3-methyl-2-butanol, 2,2-dimethylpropanol, hexanol, heptanol, octanol, nonanol, decanol, undecanol, didecanol, tridecanol, Tetradecanol, pentadecanol, hexadecanol, heptadecanol, octa- decanol, and optionally their structural isomers, 1,2-ethylene glycol, trimethylolmethane, pentaerythritol, 1, 2-propanediol and 1,3-propanediol.

In the case of polyhydric alcohols, mixed esters, for example partly with an iodobenzoic acid and partly with another acid, or incompletely esterified compounds are also suitable according to the invention.

Aromatic alcohols are especially phenols and bisphenols.

In addition to iodine, the iodobenzoic acid derivatives can also be halogenated with F, Cl or Br. Non-halogenated monoiodobenzoic acid derivatives are preferred, and the derivatives of 4-iodobenzoic acid are particularly preferred.

Mixtures of different iodine-containing benzoic acid derivatives are also suitable according to the invention.

The derivatives of iodobenzoic acid are known or are produced by known methods.

The derivatives of iodobenzoic acid are preferably used in amounts of 0.001 to

20 wt .-%, preferably from 1 to 6 wt.% Added to the plastics.

Plastic is preferably understood to mean thermoplastics, in particular transparent thermoplastics, preferably the polymers of ethylenically unsaturated monomers and / or polycondensates of bifunctional reactive compounds.

Mixtures of several plastics are also possible in the inventive sense.

Particularly suitable plastics are polycarbonates or copolycarbonates based on diphenols, the poly- or copolyacrylates and poly- or copolymethacrylates such as, for example and preferably, polymethyl methacrylate, poly- or copolymers with styrene, for example and preferably transparent polystyrene or polystyrene. rolacrylnitril (SAN), transparent thermoplastic polyurethanes, and polyolefins, such as for example and preferably transparent polypropylene types, or polyolefins based on cyclic olefins (for example, TOPAS ^®, Hoechst), poly- or copoly condensates of terephthalic acid, such as for example and preferably poly- or Copolyethylene terephthalate (PET or CoPET) or glycol-modified PET

(PETG).

Polycarbonates or copolycarbonates, in particular non-halogenated polycarbonates and / or copolycarbonates with molecular weights M _w between 600 and 100,000, preferably between 2,000 and 80,000, particularly preferably between 18,000 and 40,000, 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.

The polycarbonates can also be fully or partially brominated.

These polycarbonates are produced in a known manner from diphenols, carbonic acid derivatives, optionally chain terminators and optionally branching agents.

Details of the production of polycarbonates have been laid down in many patents for about 40 years. Examples include Schnell, “Chemistry and Physics of Polycarbonates”, Polymer Reviews, Volume 9, Interscience Püblishers, New

York, London, Sydney 1964, on D. Friday, U. Grigo, P.R. Müller, H. Nouvertne ', BAYER AG, "Polycarbonates" in Encyclopedia of Polymer Science and Engineering, Volume 11, Second Edition, 1988, pages 648-718 and finally on Dres. U. Grigo, K. Kirchner 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. Diphenols in polycarbonate production are preferred:

4,4'-dihydroxydiphenyl, 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-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) -p-diisopropylbenzene, 2,2- Bis (3,5-dichloro-4-hydroxyphenyl) propane, 2,2-bis (3,5-dibromo-4-hydroxyphenyl) propane and l, l-bis (4-hydroxvphenyl) -3, 3,5-trimethylcyclohexane.

Particularly preferred diphenols are 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, 1,1-bis (4-hydroxyphenyl) cyclohexane and 1,1-bis- (4th hydroxyphenyl) -3,3,5-trimethylcyclohexane.

Preferred branching agents are triphenols, trimesic acid (trichloride), cyanuric acid trichloride and 3,3-bis- (3-methyl-4-hydroxyphenyl) -2-oxo-2,3-dihydroindole.

To achieve improved plastic compositions, it is possible and useful that at least one further additive usually present in thermoplastics, preferably poly- and copolycarbonates, such as stabilizers (as described, for example, in EP 0 839 623 AI or EP 0 500 496 AI) in particular thermal stabilizers, in particular organic hindered phenols, hindered amines (HALS), phosphites or phosphines, by way of example and preferably triphenylphosphine, 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 or Pentaerythritol tetrastearate (PETS), flame retardants, antistatic agents, UV absorbers, for example and preferably hydroxybenzotriazoles and hydroxytriazines, fillers, foaming agents, dyes, pigments, optical brighteners, residues tion catalysts and nucleating agents or the like, preferably 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 is incorporated.

The incorporation of the esters of iodobenzoic acid and optionally the additives or mixtures of the additives is carried out in a generally customary manner, for example before or during the polymerization or by subsequent mixing with the plastic, preferably by extrusion.

The plastic compositions obtained in this way are generally in the form of solutions, dispersions, emulsions, dusts, powders, granules, platelets or flakes (molding compositions) and are used for the production of shaped articles (molded articles). The production of plastic moldings is carried out using conventional methods such as Hot pressing, spinning, extruding or injection molding.

The plastic compositions according to the invention generally contain 0.01-10% by weight, preferably 1-3% by weight of organically bound iodine.

Shaped objects are preferably translucent objects, in particular for medical applications, such as, for example, and preferably probes or joint parts or small objects that are used by children. Of course, customary shaped objects such as foils, tapes, plates, multi-wall sheets, multi-wall sheets, vessels, pipes and others can also be used

Profiles are produced with the plastic compositions according to the invention. The plastic compositions can also be processed into cast films.

The use of the plastic composition according to the invention for the production of multilayer systems is also of interest. Here, the invention contemporary plastic composition in a thin layer on a molded object made of a plastic that is not with an X-ray contrast agent. The application can take place simultaneously with or immediately after the shaping of the molded body, for example by coextrusion or multi-component injection molding. The application can also be done on the finished molded body, for example by lamination with a film or by coating with a solution.

Esters of iodobenzoic acid-containing plastic compositions are preferred for the production of small parts which are used by children, in particular for the production of toys such as building blocks.

The following examples serve to explain the invention. The invention is not restricted to the examples. Percentages and parts in the following mean percentages by weight or parts by weight.

example 1

29.3 parts of 4-iodobenzoyl chloride (Aldrich) are dissolved in 100 parts of pyridine. Then 3.1 parts of ethylene glycol (Aldrich) are added dropwise with stirring. After 10 minutes, the mixture is heated to 75 ° C. for 1 h. The product is then taken up in methylene chloride, washed with water, acid and base and dried. 98.7% of the theoretical yield of the diester are obtained. The melting point of the colorless compound was 146 ° C.

Example 2

95.5 parts of additive-free, unstabilized polycarbonate with an average molecular weight of about 30,000 (Mw by GPC), solution viscosity: η = l, 293 (Makrolon 2808 ^®, Bayer AG), together with 0.3 parts PETS and 4 parts of 1,2- Ethylene glycol-bis-4-iodobenzoic acid ester (from Example 1) was compounded at 300 ° C. using a twin-screw extruder and then injected into color sample plates (155 mm × 75 mm × 2 mm).

Example 3

The Farbmusteφlättchen from Example 2 are examined for their light stability by irradiation with a UV lamp, a Xe-WOM lamp and daylight. The results are given in Table 1.

Table 1 Light stability of 2 mm thick samples from Example 2:

Example 4

4 parts of ethylene glycol-bis-4-jodbenzoesäureester (from Example 1) are dissolved with 96 parts of polymethyl methacrylate (Plexiglas ^®) in 150 parts of methylene chloride, and processed to give a 180 .mu.m thick film and dried in vacuo. The film is then exposed for 8 hours under a UV lamp at 254 nm. No discoloration can be detected visually. Furthermore, the VIS spectra between 400 and 1200 nm are congruent before and after the UV irradiation within the scope of the measurement accuracy.

Example 5

13.3 g of 4-iodobenzoyl chloride are dissolved in 30 ml of dichloroethane and 4 ml of pyridine. 6.5 g of dibutylamine are slowly added dropwise to the solution and stirring is continued for a further 30 min at room temperature. The reaction mixture is washed with water, 10%

Sodium hydroxide solution, 10% hydrochloric acid and washed again with water, dried over sodium sulfate and finally concentrated. Yield 18 g of light yellow crystals. The product can be melted at 320 ° C with polycarbonate without discoloration.

Example 6

A cast film made of Makrolon 2808 with 5% of the product from Example 5 is produced using methylene chloride. The film is transparent and colorless. No discoloration of the eye can be observed when the film is exposed to UV light at 254 nm for 14 h.

Comparative Example 1

161.1 g (0.11 mol) of oligo- [2,2-bis (4-hydroxyphenyl) propane carbonate] chlorocarbonic acid ester (degree of polymerization approx. 5) (prepared according to U. Grigo, K. Kirchner and PR Müller "Polycarbonate" in Becker / Braun, plastic manual, volume 3/1, polycarbonates, polyacetals, polyester, cellulose esters, Carl Hanser Verlag Munich, Vienna 1992, pages 143 formula (3.9)) are dissolved in 1000 g dichloromethane. At 20-25 ° C., a clear solution consisting of 89.1 g (0.189 mol) of 2,4,6-triiodophenol, 35.6 g (0.40 mol) of 45% sodium hydroxide solution and 800 g of water is added with stirring.

After 5 minutes, 0.71 g of N-ethylpiperidine is added and the mixture is stirred intensively for 30 minutes. The dichloromethane phase is separated from the aqueous phase and washed free of electrolytes. The solvent is evaporated off and the concentrated solution is dried at 120 ° C. in a water jet vacuum. Yield: 202 g of colorless solid

Analyzes: phenolic OH: 160 mg / kg, saponifiable Cl: <0.2 mg / kg iodine content: approx. 27%

When the sample is heated in a crucible together with polycarbonate at 300 ° C. for 5 minutes, no discoloration is evident.

Comparative Example 2

94.7 parts of polycarbonate (Makrolon 2808, Bayer AG) are mixed together with 5.9% by weight of iodinated oligocarbonates from Comparative Example 1 (triiodophenol end groups) and 0.5% by weight of mold release agent PETS (pentaerythritol tetrastearate) at 280 ° C compounded in a twin-screw extruder and then injection molded into test bars of different thicknesses.

The transparency of these shaped bodies was in each case more than 85%. The X-ray detectability was demonstrated on test specimens with a thickness of 1.2-3.2 mm with the parameters customary in the medical field. Table 2 Light stability of 2 mm thick samples from comparative example 2:

Comparative Example 3

94.7 parts of Makrolon 2808 ^® are compounded together with 0.3 part of PETS and 5 parts of 4,4'-diiodobiphenyl (Aldrich) at 280 ° C using a twin-screw extruder and then injected into test bars of different thicknesses.

The transparency of these shaped bodies was in each case more than 85%.

Samples with a thickness of 2 mm are weathered for 1000 h under Xe-WOM 0.35 W / m ² without irrigation. The previously colorless samples were then colored intensely red. When such a sample is exposed to a UV lamp 254 nm for 8 h, a clearly visible red color can also be produced.

Comparative Example 4

9.87 g (0.067 mol) of oligo- [2,2-bis (4-hydroxyphenyl) propane carbonate] chlorocarbonic acid ester (see Comparative Example 1) are dissolved in 56 g of dichloromethane. At 20-

25 ° C, a clear solution consisting of 2.48 g (0.01 mol) of 4-iodobenzoic acid, 1.33 g (0.015 mol) of 45% sodium hydroxide solution and 72 g of water is added with stirring. After 5 minutes, 0.084 g of N-ethylpiperidine are added and the mixture is stirred intensively for 30 minutes. The dichloromethane phase is separated from the aqueous phase and washed free of electrolytes. The solvent is evaporated off and the concentrated solution is dried at 120 ° C. in a water jet vacuum. Yield: 9.7 g of colorless solid

Analyzes: phenolic OH: 0.09%, saponifiable Cl: 3 ppm, iodine content: approx. 4.6%

When the sample is heated in a crucible together with polycarbonate at 300 ° C. for 5 minutes, no discoloration is evident. The iodine content is too low to obtain mixtures with polycarbonate with an X-ray detectable iodine content, as in Comparative Example 2.

Comparative Example 5

A solution film consisting of 50 parts Makrolon 3208, 50 parts oligomer according to Comparative Example 4 and 0.5 part Tinuvin 234 is produced. The film shows no discoloration even after exposure for 6 hours under a UV lamp (254 nm).

Comparative Example 6

23 parts of BPA are reacted with 17 parts of phosgene and 21 parts of 2,3,5-iodobenzoyl chloride under interfacial conditions (according to WO 9859005) to form an oligomer with 2,3,5-iodobenzoyl end groups. When the sample is heated in a crucible together with polycarbonate at 300 ° C for 5 min, a clear red color is evident.

Comparative Example 7

6 parts of 4-iodobenzoic acid are heated with 94 parts of polycarbonate in a crucible at 300 ° C. for 5 minutes. 4- iodobenzoic acid separates partly through sublimation at the edge of the crucible. Comparative Example 8

4 parts of 3,5-diiodosalicylic acid are mixed with 96 parts of polycarbonate in a crucible

Heated to 300 ° C for 5 min. The mixture turns red.

Comparative Example 9

4 parts of 2,3,5-triiodobenzoic acid are mixed with 96 parts of polycarbonate in a crucible

Heated to 300 ° C for 5 min. The mixture turns red.

Comparative Example 10

A film consisting of 96 parts Makrolon 2808 and 4 parts 1,4-diiodotetrafluorobenzene (Aldrich) is produced by solution casting. After drying, the colorless and transparent film is exposed to a UV lamp at 254 nm for 6 hours. A clear red color can then be seen.

Comparative Example 11

6 parts of iohexol (Sigma) are heated with 94 parts of polycarbonate in a crucible for 5 minutes at 300 ° C. There is strong discoloration.

Claims

Patentansprflche

1. Use of iodobenzoic acid derivatives as an X-ray contrast medium.

2. Use of iodobenzoic acid derivatives for the X-ray-detectable finishing of plastics.

3. Plastic compositions containing at least one iodobenzoic acid derivative.

4. A method for producing plastic compositions as defined in claim 3, characterized in that at least one iodobenzoic acid derivative is added before, during or after the polymerization of the plastics.

5. Use of iodobenzoic acid derivative-containing plastic compositions for the production of plastic moldings.

6. Process for the production of X-ray opaque shaped bodies, characterized in that at least one plastic composition as in

Claim 3 defines as starting material.

7. Plastic moldings containing at least one iodobenzoic acid derivative.

8. X-ray detectable moldings based on (co) polycarbonates or their blends containing iodobenzoic acid derivative in amounts of 0.001 to 20% by weight.

9. Molded body produced from plastic compositions according to claim 3.

0. Molded body according to one of the preceding claims containing mold release agents, thermal stabilizers and / or UV absorbers, each in amounts of 0.001 to 1% by weight.