DE2710729A1 - POLYMER COMPOSITION AND ITS MANUFACTURING PROCESS - Google Patents

Description

The invention relates to new polyester-based polymer compositions and to their preparation and from the compositions manufactured moldings; the polymer compositions according to the invention are based on polycarbonate polymers and in particular aromatic polycarbonates and aromatic polyesters.

Polycarbonates are understood to mean polymers whose formula is the one formed from a carboxylic acid and an aromatic glycol, in particular a bisphenol
Polyester corresponds, while polyester is understood to mean a polymer whose formula is derived from an aliphatic or cycloaliphatic glycol and an aromatic dicarboxylic acid, the latter preferably being a “benzene dicarboxylic acid compound”.

O122- (E24O7-24O8) -FSBk

709838/0811

27107/9

The combination of aromatic polycarbonates with aromatic polyesters such as polyesters made from terephthalic acid or isophthalic acid in the same polymer composition poses stability problems. Although both The main components of the composition are stable and easy to mix in the molten state reactions take place in the mixture, which lead to a very rapid degradation of the polymers, which results in the occurrence of Expresses bubbles and foaming and prevents practically any technical or industrial application. This is to note that the above disadvantages of foam and blistering do not occur when two polyesters such as polyethylene terephthalate and polybutylene terephthalate are mixed together in the absence of polycarbonate.

According to the invention, the degradation reaction of the polymers in contact with one another can occur at any time Addition of a stabilizing agent to the mixture of the polycarbonate with the polyester can be interrupted.

In this way, polycarbonate-polyester compositions are available that are stable and remarkable and have unexpected properties. You can use any conventional molding, casting or injection molding process or can be processed into moldings according to any other shaping process.

The invention allows in particular the production of polyester compositions in a completely new composition range, which are often referred to as 'polymer batches' and after shaping into products with completely new, excellent mechanical, physical

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ORIGINAL INSPECTED

chemical and chemical properties. The invention allows in particular by producing batches with amorphous polycarbonates of high temperature resistance such as the usual bisphenol polycarbonates, the impact resistance and to improve thermal resistance of crystalline polyesters such as polybutylene terephthalate.

Under the name 'Mixture'

Here and in the following, a composition is understood in which the stabilizing agent is used right at the beginning the mixing operations (i.e. in particular less than 1 min after the polymers have been brought together), while the term 'copolyester' is used to denote compositions is used, in which the addition of the additive is delayed by more than 1 min and a relative significant chemical reaction takes place between the two polymeric components.

The invention also enables the products to be deformed under heat, in particular by the various products Molding process by extrusion or injection molding and gives the advantage of reducing the prime cost of the corresponding materials, with the mechanical strength properties at ordinary temperature as well as the Resistance to organic solvents remain completely unchanged. In addition, the invention Compositions easy to manufacture and process; they are made by simply mixing the ingredients.

The invention is also advantageous in that compositions are available which have a predetermined and freely selectable proportion of polycarbonate-polyester

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^: ν-; VAL INSPECTED

Contain copolymers. This is one whole range of new, special polyester products, based on the knowledge of the individual poly components could in no way be foreseen.

According to the invention, at least one aromatic polycarbonate and at least one aromatic polyester mixed together, whereupon a stabilizer is added to the mixture. The length of time during which the polymers are in contact with one another in the absence of the stabilizing agent, in particular between 0.1 min and 4 h.

According to the invention, additives suitable as stabilizers consist of phosphorus derivatives such as in particular and preferably organic phosphites, this term including all esters of phosphorous acid those, which can also exist in other forms, are understood. Can also be used according to the invention for example the phosphites which, although commonly referred to as phosphites, turn into phosphonates can convert. In the same way, other phosphorus derivatives such as metaphosphoric acid as well Ary! Phosphinic acids and arylphosphonic acids according to the invention can be used. According to the invention preferred additives are on the one hand those compounds in which the phosphorus atom has at least one and preferably two aromatic substituents such as phenyl, and on the other hand the diphosphites and especially those diphosphites whose P atom has two alkyl groups with 4-30 carbon atoms.

Phosphites generally offer numerous advantages, including 709838/081 1

ter denoting that they are in liquid form or in the form of solids are present with a low melting point, which facilitates their incorporation into the compositions according to the invention. The variety of compounds belonging to the class of phosphites also allows a selection of the additive in such a way that it also gives the composition other properties such as fire resistance able to lend.

Others, also in the compositions according to the invention Additives which can be used as stabilizers consist of the carboxylic acids and preferably the organic ones Compounds of the aromatic series, the molecules of which have at least two and preferably at least three or four Have carboxyl groups as substituents on a benzene ring. The acids can optionally from the corresponding Anhydridea are produced. The anhydrides can therefore be used as additives according to the invention in the same way are, preferably with the condition that they are present in the presence of an amount of water that their at least partial hydrolysis guaranteed.

The additives of this group include in particular, for example, stearic acid as a non-aromatic acid, However, aromatic acids such as terephthalic acid, trimellitic acid, trimesic acid or pyromellitic acid are in accordance with the invention preferred. Particularly suitable anhydrides are the anhydrides of tetrahydrofuran-tetracarboxylic acid or the anhydrides aromatic acids with at least three carboxyl groups such as trimellitic acid, pyromellitic acid and naphthalene tetracarboxylic acid usable according to the invention.

The invention extends to all compositions

? 710729

genes in which the polymers consist essentially partly of a polycarbonate, in particular a bisphenol polycarbonate, and partly of an aromatic polyester; a particularly typical example of such a polycarbonate is the polycarbonate of bisphenol A, that is to say the polycarbonate of h, V-dihydroxy-2,2-diphenylpropane; The aromatic polyesters are in particular polyesters derived from an aliphatic glycol with a particularly linear chain or a cycloaliphatic glycol and a benzene dicarboxylic acid, the glycol having 2-10 carbon atoms and the benzene dicarboxylic acid being especially terephthalic acid, isophthalic acid or mixtures thereof.

In the compositions preferred according to the invention, the polyester is in particular a polybutylene terephthalate; however, the invention is by no means restricted to these substances. The additives of the phosphite or carboxylic acid type proved to be effective in the same way for other analogous polyesters mixed with polycarbonates.

The two polymers can be present in the compositions according to the invention in all proportions. Preferred compositions contain 5-95 and preferably 20-80 parts by weight of polycarbonate to 95-5 and preferably 80-20 parts by weight polyester.

It was also found advantageous that the polycarbonate have a weight average molecular weight ^. 50,000 and the polyester, especially polybutylene terephthalate, has a number average molecular weight of £ 50,000 to To achieve polymer mixtures that can be processed into Pormkkörper that a compared to conventional crystalline

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Polybutylene terephthalate have improved impact and heat resistance.

The amount of the additive introduced into the composition according to the invention is preferably between 0.25 and 1% by weight based on the total weight of the polymers, but other amounts, generally between 0.1 and 5 wt. $ S.

According to the inventive method, the mixing of the ingredients may in each above the melting temperature of the individual polymers lying temperature, preferably, carried out between 150 and 3po ⁰ C.

According to a preferred embodiment of the invention the polymers are allowed to react together in the molten state for 1 min to 4 h and preferably 1 min to 100 min, before the stabilizer is introduced into the mixture. In this way copolyesters are obtained, in which the chemical reaction preceding the stabilization by the additive is a grafting of polyester sequences, the length of which depends on the reaction conversion achieved, on polycarbonate chains evokes.

In preferred compositions according to the invention, 0.1 to 80 % of the number of carboxyl groups derived from the polyester form ester bonds with aromatic nuclei. This means that the polyester and the polycarbonate have reacted with one another in a certain proportion to form a copolyester. In such polyesters, bonds are formed between the carboxyl groups of the polyester and the aromatic nuclei of the polycarbonate, while the carboxyl groups in the original poly

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esters with aliphatic or cycloaliphatic ones derived from the diol Groups are esterified. The ratio of the number of carboxyl groups esterified with aromatic groups to the total number of carboxyl groups (non-esterified and with aromatic, aliphatic or cycloaliphatic Groups esterified carboxyl groups) is used as a measure of the degree of copolyester formation is characteristic of the copolymer quantity ratio.

One of the main advantages of this copolyester formation is that transparent moldings are accessible in this way. In addition, the degree of copolyester formation in the particularly preferred compositions according to the invention is below 10 % and is preferably between 1 and 6 % , even more advantageously between 2.5 and 5%

According to the invention, insoluble transparent products are also accessible. In this case, the depth in the composition polymers preferably contain 40 80 wt -.% Polycarbonate and 60 - 20 wt .- ^ polyester.

The above-mentioned copolyester forming degree can for example be achieved in that the polymers at high temperature during a reaction tent in the order of 1 to 30 minutes and preferably 2.5 to 20 minutes at a temperature of preferably in the order of 250 ⁰ C with one another be reacted, in particular if the polyester is polybutylene terephthalate, before the reaction is stopped by introducing the stabilizing agent as an additive.

According to a further development of the invention, Zu-709838/0811

Composition also a reinforcing filler have, which consist of fibers or other inorganic or organic particles, in particular glass fibers may, the proportion being on the order of 5 to 40 # of the total weight of the composition and preferably is 10 to 20 weight percent.

Although it was known that the addition of glass fibers an improvement in the mechanical properties and in particular enables the impact resistance of polyesters such as polybutylene terephthalate to be increased; However, it is Surprisingly, that according to the invention an analogous improvement can also be achieved without the addition of glass fibers, for example in the case of a mixture which consists of half of polybutylene terephthalate and half of polycarbonate. In all cases it is possible according to the invention to reduce the amount of glass fibers in order to achieve a certain improvement in properties to reduce.

The compositions of the invention are also easy to manufacture. The components can, if necessary, equally also mixed together with other conventional constituents according to the usual processes in polymer technology will. Mixing can be done or continued while the composition is being processed especially in the course of molding processes that work under heating and pressure. The remarkable one thermal stability of the products according to the invention allows the use of all types of processing, including Extrusion, injection processes and injection molding processes, although also according to the invention for commercially available polymers is assumed and no lengthy or costly chemical conversions are required.

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The invention is illustrated below with the aid of exemplary embodiments explained in more detail; However, the subject matter of the invention is not restricted to the examples given.

Unless otherwise stated, the percentages are based on weight.

In addition to the terms 'batch' and 'copolyester' already defined above, the abbreviations ¹ PC 'are used for the polycarbonate of bisphenol A,' PBT 'for polybutylene terephthalate,' PET 'for polyethylene terephthalate and ¹ PCHDT' for polycyclohexylene dimethylene terephthalate / isophthalate.

Furthermore, according to the invention, in some examples, mixtures of these polyesters or copolymers and in particular a copolymer of PBT and polytetramethylene glycol is used.

example 1

As a comparative experiment, 50 wt -.% Polycarbonate of bisphenol A (Lexan 155, General Electric) containing 50% of polybutylene terephthalate (Tenite 6 Pro, manufacturer Eastman Kodak) were mixed in a roller mixer at 250 ⁰ C, whereupon the mixture at 270 ⁰ C. Die casting is processed. The result is an inhomogeneous, brown material in which there are gas bubbles which were caused by severe degradation. The total processing time in this case is 10 minutes.If the material is exposed to a higher temperature for a longer period, a foam is formed which does not allow any further shaping steps. Under these conditions

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1st conditions can be seen that such a mixture can be processed in any of injection molding machines, which require for polybutylene terephthalate temperatures of the order of 270 ⁰ C. The instability of the mixture, which is shown here by gas formation, occurs equally in all PC-PBT mixtures regardless of the origin of the components from the industrially available polymer materials.

On the other hand, mixtures according to the invention are produced by mixing together 50 wt .- / 6 polycarbonate of Bisphenol A and 50 wt. # Polybutylene terephthalate at 0.5 wt. # Of the various specified below Additives, all of which consist of phosphorus compounds. The polymers are the same as above.

The polycarbonate of bisphenol A corresponds to the formula

^N ) - 0 - c

₃
and the polybutylene terephthalate of the formula

where η and m represent integers which vary depending on the molecular weight of the polymers.

In the case of the present example, the polycarbonate have a weight average molecular weight in Of the order of 45,000 and the polybutylene terephthalate a number average molecular weight of the order of magnitude from 41,000 to. In the present and the following examples

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len, the weight average molecular weight (M) of the polycarbonate is determined by measuring the viscosity in dioxane at 30 ^° C. using the following relationship:

= 4.76 χ ΙΟ ^"21 (M,) ^{0 '68;}

the number average molecular weight (M) of the polybutylene terephthalate is determined by measuring the viscosity in a phenol-tetrachloroethane mixture (6O: 4O) at 25 ⁰ C according to the relationship

, -, x 93 ΙΟ ^"1 * (M _n) ^{0 '82} determined.

The two polymers and the additive are mixed min at 26O ⁰ C in a roller mixer. 5 A sample is then further 5 minutes at 240 ⁰ C'gepreßt. Finally, the thermal stability of the mixture is ^{measured at 260 °} C. with a capillary rheometer, the time being indicated which elapses before the release of gas in the extrudate begins. The determination is made every 5 min

to
to / 140 min. The stability period, which in fact represents a measurement of the effectiveness of the additives added, gave the following results for the various phosphites listed below:

Stability time (min)

without additive < 5

Di-n-octadecyl phosphite> 140

Triphenyl phosphite> 140

Diphenyl phosphite 70

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Dibenzyl phosphite 50

Decyl diphenyl phosphite 50

Phenyldidecyl phosphite 30

Metaphosphoric acid 20

Phenyl phosphoric acid 65

Phenylphosphinic acid 50

When examined visually, the samples produced are white, opaque and without traces of released gases. the Additives of the diphosphite type and particularly di-n-octadecyl phosphite lead to better suppression of discoloration than the triphosphites. They lead to rehearsals with excellent appearance and remarkably good surface condition, which do not stick to the mold.

It can also be seen from the above results that the stabilizing effectiveness of the triphosphite additives the greater, the more aromatic substituents the phosphorus carries.

Example 2

The procedure is as in Example 1, wherein mixtures according to the invention with 0.5% di-n-octadeyl phosphite are investigated, which are different from one another in that polymers of different origins are used which differ from one another essentially in their molecular weights. The values obtained for the stability period are given in the table below, in which

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the polycarbonate of bisphenol A (PC) is characterized by its weight average molecular weight M, while

rend polybutylene terephthalate (PBT) is characterized by its number average molecular weight M:

Pc PBT η Stability period (50 wt. Ji) (50 wt. Ji) 38000 (min) M. M. 27000 W. 29000 45OOO 38000 120 45OOO 41000 50 45OOO 41000 55 45OOO 120 45OOO > 140 30000 30th Example 3

The procedure is as in Example 1, with samples on the base of polycarbonate of bisphenol A and polybutylene terephthalate are made with a from DL-n-cf'ctadecylphosphit best organic phosphite are stabilized in an amount of 0.5 wt .- #.

The stability times measured at 260 ^° C. are listed in the table below for various relative proportions of the polymers:

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PBT 2710729 Pc (% By weight ) Stability period '■ 20 (min) 80 40 > 14O 60 50 > i4o 50 60 > 14O 40 80 > l40 20th > 14O

The stabilization of the mixture is independent of the relative proportions of the two starting polymers guaranteed according to the invention over more than 140 minutes, which correspond to the measurement limit of the method used.

Example 4

Following the procedure of Example 1, but varying the amount of additive for each sample get the following results:

. ,, .., Concentration Stability ^{Time Additlv} (Oew.-Jf) (min)

Di-n-octadecyl phosphite 1 > l40

0.5> 14Ο

0.25> l40 0.1 20

Triphenyl phosphite 1> 140

0.5> 4

The stabilizing effectiveness of the additive is significantly increased if the proportion is based on the The weight of the polymers exceeds 0.1 to 1 weight percent; the

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However, the quantity ratio is generally preferably limited to a maximum of 1 % in order to exclude adverse influences on the mechanical properties of the product and not to increase the viscosity of the composition in the molten state, which is associated with the ease of processability, too much.

Example 5

There are two compositions of 50 wt -.% PoIycarbonat of bisphenol A and 50 wt -.% Of polybutylene terephthalate produced. The two polymers are ^{mixed at 250 °} C. in the molten state. In the course of mixing, however, 5 and 10 minutes after the two polymers have been brought together, 0.5% by weight of di-n-octadecylphosphine is added.

Test specimens are then produced from the two compositions obtained by pressing at 240 ^{° C. for 5 minutes.} The stability time then measured as in Example 1 is in all cases over 140 minutes, which corresponds to the measurement limit.

In the course of the mixing prior to the addition of the stabilizing agent, however, the compositions take on a yellow-brown color, which is indicative of the chemical reaction between the polymers. In an investigation of this reaction, in which the behavior of compositions that ^{had reacted at an elevated temperature (260 °} C.) and over a longer period of time (30 and 60 min) was investigated with respect to various solvents, as well as on the basis of IR measurements and viscosity measurements in molten state and in solution is also to be assumed that the reaction

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- vr -

tion with chain termination of the polymers and grafting of polybutylene terephthalate sequences onto the polycarbonate chains connected is.

Example 6

In the manner described in Example 3, a series made of PC-PBT mixtures in which the PBT content is varied from 0 to 100 wt .- #, whereby the physical and mechanical properties of samples are tested.

The measurement results obtained are shown in the table below. From them it appears that the received Mixtures correspond to a whole range of products, the properties of which progressively vary depending on the relative Quantities of the two polymers between those of the polycarbonate and those of the polybutylene terephthalate change and which are accessible due to the use of the additive according to the invention that stabilizes the composition while preventing a harmful interaction or reaction between the two polymers.

The following test methods were used;

The degree of crystallinity was determined using a Differentialmikrokalorimeter (Dupont Thermal Analyzer) under the assumption that the heat of fusion of crystalline polybutylene terephthalate century, 5 cal / g. The results are based on the total weight of the samples.

The modulus of elasticity at 100 ⁰ C and at 170 ⁰ C were determined from the curves of the change in the modulus as a function of the temperature, due to with a

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The measurements carried out by the Gehmann apparatus were recorded.

The notch or impact strength was determined as impact / tensile strength according to the ASTM 1Ü22-21T standard and as Izod impact strength measured according to the ISO R18O standard.

The values of the flexural modulus and the elastic limit were determined in accordance with the ISO RI7B standard.

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Properties of the mixture PC

4,5000) - PBT (Vi _n = 41,000)

O CO CO U) CO

Together
^: the pi?
I PC OO Strike / pull.
strength"
(kg.om/cm j \ Izod- ^:
Beat
sturdiness
(kg »cm / cm) Bending module
(kg / cm ² ) Elastic
limit of activity
. (kg / cm ² ) . Module (Gehmann) at ^:
: loo ° c 170 ° c.
; (10 ⁵ dynes / cm ² ): : 0.3 i
iu, 27 I. i 100 i
i 90 i ': 350
': 335 : 150
: (ductile) : 19000 : 1000 : 240
: 200 : 0.35: i ΘΟ: : 31D
* : 16 : 22400 : 1000 : 160 Ί 0.8 ί : 7U: : 304 : : : : 130 ί 1.8 I. ': 60 i : ^ 75 : 13.5 : 23000 ■
96CJ 1 10 I 2.7 i : '5U! : 25D : 10 : 22b00 ^: 960 : 9U 4: : 40: ί ^ 3U : 9 : 22100 960 55 '. 6 i i 30 i • 163 : - - 42 e: : '20 ': ': 160 : 8th : 22000 900 34 10: : 10: : 154 : • - 34 12 i
• : 0: ': 129 : 6 : 23000 850 34 composition
above
: PBT (50 O
10 20th . 30th 4L) 50 6u 70 80: 90 ': 100 ': Crystal.
line
: w>: 0
'. 2.2. : 6.8 7.8 10.5 11.8 15th 18th 20th 23.6 27

-X-

Example 7

The properties of a mixture according to the invention with 50 wt .- # polycarbonate of bisphenol A and 50 wt .- # polybutylene terephthalate with addition of 0.5 wt -.% Of di-noctadecylphosphit compared with the properties of pure polybutylene terephthalate. These properties are already listed in the table of the previous example. The comparison shows the favorable applicability of the mixture according to the invention with replacement of the polybutylene terephthalate in the majority of its applications. It can be found particularly in the manufacture of mechanical parts using low, which can be easily produced by press molding or injection molding at temperatures in the order of 270 ⁰ C.

The advantage of the mixture according to the invention over PBT lies in particular in its impact resistance. In the case of the Izod impact strength, the improvement is about 70 %, and in the case of the impact / tensile strength it reaches over 90 %. The temperature resistance of the mixture is also excellent; the modulus at 100 ^° C. is almost three times better than that of pure polybutylene terephthalate.

The improvement in impact resistance is still evident after the specimens have been kept at high temperature for a longer period of time clearly pronounced ^ as from the following test results it emerges:

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Impact Z tensile strength Izod impact strength (kg.cm/cm ² ) (kg.cm/cm)

PC-PBT mixture 100 ⁰ C 250 10 after 7 days 125 ⁰ C 191 8.6 150 ⁰ C 161 7.6 170 ⁰ C 150 7.5 • * 84 6.9 pure PBT 170 ⁰ C 129 6th after 7 days 11 2.1

After 7 days at 170 ^° C., the mixture according to the invention still has more than 50 % of its original impact strength, which shows a considerably higher thermal aging resistance compared to pure polybutylene terephthalate, which under the same conditions only has less than 10% of its tensile impact strength ».

Example 8

A mixture similar to that investigated in Example 7 is obtained Batches produced, the polycarbonate (Lexan 135 type, molecular weight 45,000) being replaced by a polycarbonate replaced by bisphenol A (Lexan 145) with a molecular weight of 3,000 will. The Izod impact strength of the mixture gives a value of 9.

Example 9

In a mixture of 50% by weight of polycarbonate of bisphenol A and 50 % of polybutylene terephthalate with the addition of

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0.5 wt .- # PL-η-octadecylphosphite, which is obtained by the method described in Example 1 for the production of PC-PBT mixtures, 10 wt .- % glass fibers based on the total weight of the composition thus obtained are introduced.

The mechanical properties of the molded articles obtained from this composition are described below in comparison with the properties of polybutylene terephthalate itself, which is reinforced with the same amount of glass fibers (10 wt -% of the composition.) Stated:

Sample based on;

Impact / tensile strength (kg «cm / cm) Izod impact strength (kg · cm / cm modulus of elasticity (10 ° dyn / cm ² )

at 20th ⁰ C It 100 ⁰ C If 170 ° C

PBT PC-PBT 40 76 6.3 12.7 220 220 72 97 35 10

The reinforced PC-PBT mixtures can be processed and used for the same purposes in the same way as reinforced polybutylene terephthalate. However, the improvement in the mechanical properties is clearly evident from the above results: the impact strength, based on the Izod impact strength, is practically doubled, and the modulus of elasticity at 100 ^° C. is still 30 # above that of reinforced pure PBT.

Example 10

The physical and mechanical properties of PC-PBT copolyester samples prepared as in Example 5 were examined, using the stabilizing agent

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is added after 5 and 10 rain reaction time of the polymer at 250 ⁰ C.

The rate of crystallization is found to be slower than that of the mixtures in the above examples. The glass transition point was based on the curves of the dependence of elastic modulus on temperature, taken apparatus Gehmann with a determined, is of the order of 70 ⁰ C.

The impact strength as impact / tensile strength provides a remarkably favorable value that corresponds to that of pure Polycarbonate is comparable and is significantly above the value of batches of the same composition.

The values obtained in the impact and bending tests according to the standards already mentioned in Example 6 are:

Reaction impact / tensile Izod impact flexural modulus elasticity time (min) strength strength ₂ limit (kg'cm / cm ^) (kg cm / cm) (kg / cm) (kg / cm)

5 513 8.2 22600 920 10 320 8.1 21100 830 Example 11

a) In a comparative experiment, a mixture of 50% polycarbonate (Lexan 135) and 50 # Polyäthylenterephtha lat by mixing in a roller mixer at 250 ⁰ C for 5 minutes. A sample is then pressed for 5 minutes at 270 ⁰ C. The thermal stability is measured at 290 ⁰ C as described in Example. 1 The stability time obtained is around 30 minutes.

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b) A mixture analogous to the above, with further addition of 0.5 wt .- ^ di-η-octadecyl phosphite to Composition made. The measured stability period increases thereby to 80 min.

c) Mixtures of 50 % polycarbonate and 50 % PET with the addition of 0.5 % di-nctadecyl phosphite are produced using the same process. The physical and chemical properties of samples obtained from these batches are measured. The results obtained are in the table below in comparison with the properties of

pure PET stated:

pure PET PC-PET quantity

Crystallinity in% (+) Impact / tensile strength (kg · cm / cm ² Izod impact strength (kg.cm/cm) Gehmann module at 100 ⁰ C

170 ⁰ C

Flexural modulus (kg / cm) elastic limit (kg / cm)

^{v +} 'Calculated assuming a heat of fusion of 28 cal / g for crystalline PET.

The Polyäthylenterephtha lat used in this example has the formula

CVJ 30.2 24.5 ) 1 62 209 2.4 9.8 .2.1O ⁹ 6.9.ίο ⁹ .5.1O ⁹ 2.6.10 ⁸ 274OO 232OO 1100 930

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in which η is an integer.

Example 12

a) In a comparative experiment, a mixture of
50 wt -.% Polycarbonate (Lexan 135) and 50% Polycyclohexyiendimethylenterephthalat / isophthalate by 5 minutes of mixing at 250 ⁰ C in a roller mixer. The stability time is then measured using the same method as in Example 1; it is less than 5 minutes.

b) An analogous to the above mixture with the further addition of 0.5 wt -% produced di-η- Qstadecylphosphit to the composition.. As a result, the measured stability period now increases to IhQ min.

c) By the same procedure mixture of 50% polycarbonate and 50% polycyclohexylenedimethylene terephthalate / isophthalate (PCHDT) with addition of 0.5 wt are -.% Dj. _nc-ctadecyl phosphite, based on the total polymer weight, prepared, whataui the physical and chemical properties of samples prepared from these mixtures are measured.

The results obtained are in the table below in comparison with the properties of pure
PCHDT stated:

Impact / tensile strength (kg cm / cm ² ) Izod impact strength (kg cm / cm) Flexural modulus (kg / cm2)
Elastic limit (kg / cm ² )

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pure PCHDT PC-PCHDT quantity cm ² ) 78 258 cm) 16 21000 2Ο9ΟΟ 745 9 ^ 2

The polyester PCHDT used in this example has the formula

in which η means an integer.

Example 13

The polymer components contain 50 wt -.% Of the same PC and PBT polymers l in a sample "it" were ow the composition further comprises 0.5 Oew.-Jt of an additive based on the polymer-.iesamtgewicht the.. the two polymers are mixed with the additive as described in Example 1, the molten polymers being brought into contact with one another about 10 s before the additive is added.

The stability time measured as in Example 1 is listed below for various acids and anhydrides used as additives:

...... stability period

^Addltlv (min)

without under 5

Terephthalic acid 15

Trimellitic acid (1,2, ^ - benzene- ₁₂

tricarboxylic acid)

Triraesic acid (1,3,5-benzene tri- Q ₀

carboxylic acid)

Pyrocnellitic acid (1,2,4,5-benzene, _Q

tetracarboxylic acid)

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a. 5

partially hydrolyzed anhydride
the 2,3,4,5-tetrahydrofuran-tetra-30

carboxylic acid

Trimellitic anhydride with another ₂ g carboxylic acid group

partially hydrolyzed pyromellitic acid _2C anhydride ^D

1,4,5,8-naphthalenetetracarboxylic anhydride 7

Example 14

As in Example 5, copolyesters are prepared whose degree of crystallinity is determined by differential microcalorimetry is measured with the Perkin-Elmer DSC 2 device. PUr which after a reaction time of 5 min (before the addition of the Stabilizing agent) becomes a half crystallization time obtained from 13 min 10 s. For the sample obtained after a reaction time of 10 min No crystallization was observed in this experiment.

Example 15

A copolyester is produced as in Example 5, with the difference that the PBT and the polycarbonate are left in contact with one another for 17 minutes before the additive is introduced. The sample is then extracted with methylene chloride in a Soxhlet apparatus for 7 hours. The solubility of the sample is about 25 %. Analogous values are obtained for samples which were kept longer at the reaction temperature (30 min), the additive being added after 17 min. Analogous values are also obtained for a reaction time of 6 min at 260 or

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270 ⁰ C obtained.

Example 16

Copolyesters are produced as in Example 5, a reaction time of 10 min at 250 ^° C. being selected and the proportions of the constituents being varied. The stability time and the Izod impact strength are measured as in Example 1.

The following results were obtained:

Composition Impact resistance Stability time (% by weight ) PC (% by weight ) PBT (kg. Cm / cm) , (min)

7.5 100

8.7 100

9.1 100

9.4 100

10.2 100

20th 80 4o 60 50 50 60 40 80 20th Example 17

According to the procedure described in Example 1, amounts are prepared from polycarbonate of bisphenol A (Lexan 135) and a copolymer of PBT and tetramethylene glycol, which are stabilized with 0.5 wt .- # di-η-octadecyl phosphite. As PBT-tetramethylene glycol copolymer were the commercial products Hytrel 7245 (glass transition point of about 0 ⁰ C) and Hytrel 5555 (glass transition point at about -40 ⁰ C) was used (manufactured by Dupont de Nemours). Mixing and PormgeDung be carried out at 240 ⁰ C.

709838/0811

Composition Izod impact strength Stability time

(Wt .- ^) (kg. Cm / cm) (min)

70 % PC + 30 % Hytrei 7245 9.3 65

50 % PC + 50 % Hytrei 7245 6.9 68

30 Ji PC + 70 % Hytrei 7245 12.9 60

50 % PC + 50 % Hytrei 5555 9.6 60

Example l8

It is a mixture of 50 wt -% produced PC, 25 wt .- ^ PBT and 25 wt .- # · PET as in Example 1 and 0.5 wt .- ^ (based on the total weight of the polymer blend) of di-n. -octadecyl phosphite stabilized.

The Izod impact strength of the molded sample is 10.9 kg.cm/cm.

Example 19

Samples analogous to the samples from Example 15 are examined by NMR spectrometry to determine the degree of copolyester formation or the percentage degree of conversion, the number of terephthalic groups with aromatic ester functions being determined based on the total number of carboxylic acid groups (which may have been esterified) on the terephthalic groups . The values obtained at a temperature of 260 ^° C. are 9 % for a reaction time of 17 min and 4 % for a reaction time of 8 min.

Example 20

The procedure is the same as in Example 5, 709838/081 1

PC-PBT copolyesters (50:50 wt. - $) are prepared using 0.5 wt .- # trimesic acid (1, ji ^ -Benzoltricarbonsäure) as a stabilizing agent and the stabilizing agent is mixed with the polymer mixture after 5 or 10 minutes at 250 ⁰ C is added.

_t *

Response time Izod impact strength Stability time at 260 ° C (min) (kgcm / cm) (min)

5 9.6 50

10 9.5 50

The invention is not restricted to the modes of execution and process conditions given in the examples; other corresponding embodiments are also included in the concept of the invention.

709838/0811

Claims (11)

Expectations "_."'*. "J- '.. 1. Polymer composition, characterized in that that they have 5 to 95 parts by weight of a polyester and 95 to 5 parts by weight of a polycarbonate as well a stabilizing agent that prevents reaction between the polycarbonate and the polyester, in an amount from preferably 0.1 to 5% by weight based on the total weight which contains polymers. 2. Polymer composition according to claim 1, characterized in that that the polyester and the polycarbonate are partially copolymerized. 3. Polymer composition according to claim 2, characterized in that 0.1 to 60 % of the total number of carboxyl groups derived from the polyester are esterified with aromatic groups of the polycarbonate. 4. Polymer composition according to claim 3, characterized in that the number of carboxyl groups esterified with aromatic groups, based on the total number of esterified and non-esterified carboxyl groups, is less than 10 % and preferably 1 to 6 % . 5. A method for preparing the polymer composition according to any one of claims 1-4, characterized in that a Polyester and a polycarbonate are mixed in a molten state and the molten mixture is a stabilizer is added, which prevents a reaction between the two polymers. 709838/0811 ORIGINAL INSPECTED I ² 6. The method according to claim 5, characterized in that the polyester and the polycarbonate ^{are brought into contact with one another in the molten state at a temperature of 150-300 °} C. for 0.1 min to 4 h before the stabilizing agent is introduced. 7. The method according to claim 5 or 6, characterized in that a phosphorus compound or as a stabilizing agent a carboxylic acid is used. 8. The method according to claim 7, characterized in that an organic phosphite in an amount of 0.15 wt. % Based on the total weight of the polymers is used as a stabilizing agent, 9. The method according to claim 7, characterized in that a carboxylic acid and preferably as stabilizing agent an aromatic carboxylic acid is used, in the molecule of which a benzene ring, a naphthalene system or a tetrahydrofuran ring carries at least two and preferably three or four carboxyl groups. 10. The method according to any one of claims 5-9 »characterized in that that the polymers 1 to 100 minutes in the molten state before the addition of the stabilizer to Reaction to be brought. 11. Use of the polymer composition according to any one of claims 1-4 for the production of moldings. 709838/081 1