DE2749261C2 - Molding compound - Google Patents

Description

R.

r;

Ri

OH

(D

wherein -X- is -Ο-, -S-, -SO ₂ -, -SO-, -CO-, an alkylene group having 1 to 4 carbon atoms or an alkylidene group having 1 to 4 carbon atoms and R 1, R ₂ , R ₃ , R ₄ , R ',, R ₂ , R ₃ and R _{4 are} identical or different and each represent a hydrogen atom, chlorine atom, bromine atom or an alkyl radical having 1 to 4 carbon atoms, or is derived from a functional derivative thereof, and (B) 0.01 to less than 2% by weight, based on the aromatic copolyester (A), of a phosphorus-containing component, characterized in that component (B) is a phosphorus-containing compound of the general formula II:

(H)

where η is 0 or an integer from 1 to 3 and R is an alkyl radical having 1 to 18 carbon atoms stands, wherein the hydrogen atoms of the alkyl radical are partially replaced by a halogen atom or a hydrocarbon radical can be replaced, or a mixture of such phosphorus-containing Connections is.

2. Molding composition according to claim 1, characterized in that the molar ratio of the terephthalic acid units to the isophthalic acid units in the copolyester (A) is 7: 3 to 3: 7, preferably 1: 1.

3. Molding composition according to claim 1, characterized in that the amount of the phosphorus-containing component (B) 0.02 to 1% by weight, preferably 0.05 to 0.5% by weight, based on the aromatic copolyester (A), is.

4. Molding composition according to claim 1, characterized in that the phosphorus-containing component (B) is a A compound of the formula II is where η stands for the integer 1 or 2 and R stands for an alkyl radical having 1 to 10 carbon atoms stands.

5. Molding composition according to claim 1, characterized in that the phosphorus-containing component (B) bis (2-chloroethyl) phosphate or mono- (2-chloroethyl) phosphate.

6. Molding composition according to claim 1, characterized in that the phosphorus-containing component (B) is a Mixture of bis (2-chloroethyl) phosphate and mono- (2-chloroethyl) phosphate, a mixture of monobutyl phosphate and dibutyl phosphate or a mixture of mono- (2-ethylhexyl) phosphate and di- (2-ethy Ihcxy I) phosphate is.

The invention relates to a molding composition based on

(A) an aromatic copolyester which is derived from (a) a mixture of terephthalic acid and / or a functional derivative thereof and isophthalic acid and / or a functional derivative thereof, the Terephthalic acid units / isophthalic acid unit molar ratio is about 9: 1 to about 1: 9, and (b) of at least one bisphenol of the general formula I:

R,

HO

OH

(I)

wherein -X- stands for -O-, -S-, -SO, -, -SO-, -CO-, an alkylene group with 1 to 4 carbon atoms or an alkylidene group with 1 to 4 carbon atoms and R ,, R ?, R ₁ , R ₁ , Ri, Ri, R'i and ΚΊ

are identical or different and each represent a hydrogen atom, chlorine atom, bromine atom or an alkyl radical having 1 to 4 carbon atoms, or is derived from a functional derivative thereof, and
(B) 0.01 to less than 2% by weight, based on the aromatic copolyester (A), of a phosphorus-containing component.

Known methods for the preparation of such aromatic copolyesters are, for. B. the interfacial polycondensation, in which an aromatic dicarboxylic acid chloride dissolved in a water-immiscible one organic solvent, is mixed with an alkaline aqueous solution of a bisphenol, which Solution polycondensation in which a bisphenol and an acid chloride in an organic solvent are heated, and the melt polycondensation, in which a phenyl ester of an aromatic dicarboxylic acid and a bisphenol are heated as e.g. B. in US-PS 38 84 990 and 39 46 091 is described.

It is also known that aromatic copolyesters, which are derived from aromatic dicarboxylic acids and bisphenols, compared with polyesters, which are derived from aromatic dicarboxylic acids and aliphatic alkylene glycols derive, have superior properties. In particular, these copolyesters have many superior properties, z. B. mechanical properties such as tensile strength, elongation, flexural strength, flexural recovery and impact resistance, heat distortion temperature, dimensional stability, electrical properties and Flame retardancy. Because of these superior properties, these copolyesters are known to be for one wide range of applications, for example for the production of various moldings, films, fibers and coating materials, for example by extrusion or injection molding, are suitable.

The aromatic copolyesters obtained by the above methods take as produced often yellow or brown in color. It is also stated that aromatic copolyesters during injection molding, extrusion and other deformation processes that lead to the formation of common Molded products or films are applied yellow in color. Such discoloration is extremely uncomfortable, if the resulting moldings are to be color-free. If a pigment continues in a molding compound is incorporated to achieve a desired color, then the color differs in this case of the end product often differs significantly from the desired color.

The aromatic copolyesters have a high softening temperature and are therefore often used under high temperature conditions used. However, the discoloration phenomenon described above generally progresses continues at high temperatures and deteriorates the transparency of the moldings. Such products therefore cannot be used for applications where there is a transparency and the lack of a Color arrives at high temperatures.

Such discoloration also occurs when the polycondensate decomposes. Such a discoloration therefore causes an irregular reduction in the inherent viscosity of the polycondensates which the moldings are formed and deteriorates the useful properties of these polycondensates. One therefore, such discoloration is extremely disadvantageous when uniform products are to be obtained. To overcome this problem is already known to sodium dithionite (see e.g. JP-A-11 297/63) or polyphenylene or to add active anthracene (see, for example, JP-A-23 418/70). However, these methods are not complete satisfactory results when using aromatic copolyesters at high processing temperatures are exposed.

Compounds of naphthylamine, diphenylamine, ethylenediamine and aromatic amine type are considered to be Antioxidants used for rubber. Although these amine-type compounds are used as Antioxidants for plastics can reduce the decomposition of plastics, but worsen them their color disadvantageously. The resulting moldings are therefore strongly colored. As a means of prevention the discoloration of aromatic copolyesters are still organotin mercaptide compounds, according to JP-A-51 048/73, various kinds of acid anhydrides according to JP-A-23 254/74, epoxy compounds according to JP-A-22 754/76 and phosphite compounds according to JP-A-16 558/77. As stabilizers for aromatic copolyesters there are also pentaerythritol phosphite compounds according to DE-OS 26 33 944, phosphonite compounds according to JP-A-23 564/76, phosphorous acid according to JP-A-36 753/74, a mixture of phosphorous acid and trialkyl or triaryl phosphite according to JP-A-36 752/74, polymeric Triphosphite esters according to JP-A-23 255/74 and trialkyl or triaryl phosphites according to JP-A-51 047/73 known.

Aromatic copolyesters also have the serious disadvantage that when molded products are made therefrom Left to stand in hot water or steam for long periods of time will result in water cracking occurs. Water cracking is a phenomenon in which cloudiness or a network of fine Cracks occurs on the surface or inside the molded body. This phenomenon is already in the literature has been described. The formation of water cracks occurs in whole or in part in molded articles made from aromatic copolyesters after treatment in hot water or steam. The occurrence of such water cracking not only causes a loss of transparency in the moldings, but also makes them brittle. as As a result, the impact resistance and the elongation at break are reduced and the moldings break easily under a bending stress or an impact force.

Some methods are already known to prevent water cracking in molded articles made from aromatic To prevent copolyesters. One of these methods is, for example, that one polyethylene terephthalate mixed with the aromatic copolyester, the mixture melts and shaped into moldings (cf. z. E.g. U.S. Patent 3,946,091). In another such process, polyethylene p-hydroxybenzoate becomes the aromatic Copolyester added (see, for example, US Pat. No. 3,884,990).

While these methods are effective in preventing the occurrence of water cracking (referred to herein simply as Cracking is referred to), but they are not capable of aromatic copolyesters ucucn to stabilize and improve their color via heat.

The object of the invention is therefore to provide a molding composition based on an aromatic copolyester which is stabilized against heat and which is used for the production of shaped bodies which do not show any discoloration, do not develop any discoloration even at high temperatures and which do not crack even in steam or hot water.

This object is achieved according to the invention by a molding compound of the type mentioned at the outset, which thereby is characterized in that component (B) is a phosphorus-containing compound of the general formula II:

Il

(R- O) -P- (OH), (II)

where η has the value O or an integer from 1 to 3 and R stands for an alkyl radical having 1 to 18 carbon atoms, the hydrogen atoms of the alkyl radical being partially replaced by a halogen atom or a hydrocarbon radical, or a mixture of such phosphorus-containing compounds is.

Moldings which are produced from the molding compositions according to the invention show a considerably reduced rate Discoloration. Even if they are exposed to high temperatures, they will develop little discoloration and show good stability to heat. Furthermore, it is even in hot water or on contact With steam, the cracking in these moldings is considerably reduced and the moldings are retained good dynamic properties and good transparency.

A mixture of about 90 to about 10 mol% terephthalic acid is used to produce the aromatic copolyester and / or a functional derivative thereof and about 10 to about 90 mol% isophthalic acid and / or a functional derivative thereof, reacted as an acid component with the bisphenol. Preferably a Mixture of 30 to 70 mol% terephthalic acid and / or a functional derivative thereof and 70 to 30 mol% Isophthalic acid and / or a functional derivative thereof is used. Aromatic copolyesters from the bisphenol and a mixture of 50 mol% terephthalic acid and / or a functional derivative thereof and 50 mol% isophthalic acid and / or a functional derivative thereof are particularly preferred.

The molar ratio of the bisphenol units to the sum of the terephthalic acid and isophthalic acid units is essentially equimolar.

Suitable functional derivatives of terephthalic acid or isophthalic acid are, for. B. acid halides, dialkyl esters and diaryl esters. Preferred examples of acid halides are e.g. B. terephthaloyl dichloride, isophthaloyl dichloride, Terephthaloyl dibromide and isophthaloyl dibromide. Preferred examples of dialkyl esters are z. B. dialkyl esters of terephthalic acid and isophthalic acid with 1 to 6 (especially 1 to 2) carbon atoms in each alkyl part. Preferred examples of diaryl esters are diphenyl terephthalate and diphenyl isophthalate.

.15 Examples of suitable bisphenols of the general formula I are 4,4'-dihydroxydiphenyl ether, bis (4-hyclroxy-2-methylphenyl) ether, Bis (4-hydroxy-3-chlorophenyl) ether, bis (4-hydroxyphenyl) sulfide, bis (4-hydroxyphenyl) sulfone, Bis (4-hydroxyphenyl) ketone, bis (4-hydroxyphenyl) methane, bis (4-hydroxy-3-methylphenyl) methane, Bis- (4-hydroxy-3,5-dichlorophenyl) -methane, bis- (4-hydroxy-3,5-dibromophenol) -methane, i, l-bis- (4-hydro \ yphenyl) -ethane, 2,2-bis- (4'-hydroxy-3'-methylphenyl) -propane, 2,2-bis- (4'-hydroxy-3'-chlorophenyl) -propane, 2,2-bis- (4'-hydroxy-3 ', 5'-dichlorophenyl) -propane, 2,2-bis- (4'-hydroxy-3', 5'-dibromophenyl) -propane and 1,1-bis (4'-hydroxyphenyl) -n-butane. 2,2-bis- (4'-hydroxyphenyl) propane, often referred to as bisphenol A. is most typical and available.

Typical examples of functional derivatives of bisphenols are their metal salts and their diesters with aliphatic ones Monocarboxylic acids with 1 to 3 carbon atoms. Preferred functional derivatives of bisphenols are the sodium salts, the potassium salts and the diacetate esters. The bisphenols can either be used alone or as Mixture of two or more can be used.

These aromatic copolyesters can be produced, for example, by interfacial polycondensation, in which a solution of an aromatic dicarboxylic acid chloride in a water-immiscible organic Solvent is mixed with an alkaline aqueous solution of bisphenol, by solution polycondensation, in which a bisphenol and an acid chloride are heated in an organic solvent, and by melt poly condensation in which a phenyl ester of an aromatic dicarboxylic acid and bisphenol be heated, as described for example in US-PS 38 84 990 and 39 46 091, take place.

In order to ensure that the aromatic used in the molding compositions according to the invention Copolyesters have good physical properties if they should have an inherent viscosity (// ",,,) from about 0.3 to about 1.0, preferably 0.4 to 0.8, according to the following relationship.

_ \ og _e t \ / r,

¹ HnIi p: ·

Here, t _{t means} the fall time (in see) of a solution of the aromatic copolyester in a solvent, I ₂ the fall time (in see) of the solvent and C the concentration (in g / dl) of the aromatic copolyester in the solution. The logarithmic viscosity is determined ^{at 25 °} C. in a 1,1,2,2-tetrachloroethane / phenol mixture (weight ratio 4: 6).

Interfacial polycondensation, in which a solution of terephthaloyl dichloride and isophthaloyl dichloride in an organic solvent is mixed with an alkaline aqueous solution of bisphenol with stirring, is particularly suitable for the production of the aromatic copolyesters, since this process in particular leads to aromatic copolyesters with relatively little discoloration.
Suitable individual examples of phosphorus-containing compounds of the general formula II are Orthophos-

phosphoric acid, monomethyl phosphate, dimethyl phosphate, trimethyl phosphate, monoethyl phosphate, diethyl phosphate, Triethyl phosphate, monoisopropyl phosphate, diisopropyl phosphate, triisopropyl phosphate, monopropyl phosphate, Dipropyl phosphate, tripropyl phosphate, monobutyl phosphate, dibutyl phosphate, tributyl phosphate, (DibutylMmonoäthyU-phosphate, mono- (2-ethylhexyl) -phosphate, di- (2-ethylhexyl) -phosphate, tri- (2-ethylhexyl) -phosphate, Monooctyl phosphate, dioctyl phosphate, trioctyl phosphate, monoisodecyl phosphate, diisodecyl phosphate, Triisodecyl phosphate, tris (2,3-dichloropropyl) phosphate, monolauryl phosphate, dilauryl phosphate, tnlauryl phosphate, Monotridecyl phosphate, ditridecyl phosphate, tristridecyl phosphate, monostearyl phosphate, Distearyl phosphate, tristearyl phosphate, mono- (2-chloroethyl) phosphate, bis- (2-chloroethyl) phosphate, tris (2-chloroethyl) phosphate, Mono- (2-bromoethyl) -phosphate, bis- (2-bromoethyl) -phosphate, tris- (2-bromoethyl) -phosphate, Mono- (3-chloropropyl) phosphate, bis (3-chloropropyl) phosphate, tris (3-chloropropyl) phosphate, mono- (3-bromopropyl) phosphate, bis (3-bromopropyl) phosphate, Tris (3-bromopropyl) phosphate, mono- (2-methyl-3-chloropropyl) phosphate, Bis (2-methyl-3-chloropropyl) phosphate, mono- (1,2-dichloroethyl) phosphate and bis (1,2-dichloroethyl phosphate. These phosphorus-containing compounds can be used either individually or as a mixture will.

The use of alkyl phosphates or dialkyl phosphates of the formula II, in which η is the whole number 1 or 2 and R _{1 stands} for an alkyl group with 1 to 10 carbon atoms, or of mixtures of alkyl phosphates and dialkyl phosphates is particularly preferred, since these can give aromatic copolyester compositions, which have particularly well-balanced properties in terms of color, heat stability, crack resistance and dynamic properties.

The amount of the phosphorus-containing component (B) added to the aromatic copolyester varies depending on the type of phosphorus-containing compound used, but is within 0.01 to less than 2% by weight preferably 0.02 to 1.0% by weight, particularly preferably 0.05 to 0.5% by weight, based on the weight of the aromatic Copolyester (A). When the amount of the phosphorus-containing component (B) is less than 0.01% by weight is, the effect of preventing coloring, heat decomposition and cracking is insufficient. On the other hand, when the amount of the phosphorus-containing component (B) exceeds 2% by weight, the dynamic properties of the aromatic copolyester deteriorate.

The addition of the phosphorus-containing component (B) to the aromatic copolyester (A) can be carried out in various ways Methods are done. When using interfacial polycondensation, in which a solution of a Dicarboxylic acid chloride in an organic solvent and an alkaline aqueous solution of a bisphenol be stirred, the phosphorus-containing component can be prior to the polycondensation to each of the monomers are given. If the polycondensation product as a solution of the aromatic copolyester after Polycondensation is isolated, a solution of the phosphorus-containing component can be added to the solution of the aromatic Copolyesters are added. If the aromatic copolyester is isolated as a solid, the phosphorus-containing component can simply be added to the aromatic copolyester. Furthermore, the phosphorus-containing components are incorporated into the aromatic copolyester in such a way that the aromatic Copolyester in a solution or suspension of the phosphorus-containing component in a solvent, such as methanol or acetone, and after immersion, the solvent is evaporated. at The phosphorus-containing component can be used together with the monomers using melt polycondensation be fed at the time of polycondensation. Alternatively, the phosphorus-containing component to chips or powders of the aromatic copolyester during the molding process, for example in injection molding or extrusion. When the phosphorus-containing component becomes a Powder or chips of the aromatic copolyester are added and the mixture is shaped, then can Molded articles having uniform color and properties can be obtained.

The aromatic copolyester can also contain various additives, such as antioxidants, UV absorbers, and antistatic agents and flame retardants depending on the purpose. So z. B. the according to the invention The effect achieved can be further increased by the phosphorus-containing component together with adds an antioxidant. Examples of suitable antioxidants are conventional phenolic antioxidants, Phosphite-type antioxidants, amine-type antioxidants, sulfur-containing compounds, organometallic compounds and epoxy compounds. Furthermore, plasticizers, pigments and Lubricants are incorporated into the molding composition according to the invention. Alternatively, the aromatic Copolyesters can also be reinforced by glass fibers.

When an aromatic halogen compound such as decabromodiphenyl oxide, a conventional resin composition is added in order to make them fire-retardant, then a molded article produced therefrom is discolored often yellow-brown, which is probably due to thermal decomposition. Even in one of these In the case, however, the molding composition according to the invention is stabilized against heat and the discoloration is pronounced prevented.

If desired, the molding composition according to the invention can contain at least one further polymer, such as a polyalkylene terephthalate (e.g. polyethylene terephthalate, or polybutylene terephthalate), polyethylene oxybenzoate Polycarbonate, polyethylene, polypropylene, a polyamide, polyurethane, polystyrene, an ABS resin, an EVA copolymer, a polyacrylate, polytetrafluoroethylene, polymethyl methacrylate, polyphenylene sulfide or a rubber contain. That is, it can also be a mixture of the aromatic copolyester and another Polymers as noted above can be used. In this case, too, the one used according to the invention applies phosphorus-containing component (B) has a pronounced effect.

The degree of discoloration or degradative decomposition of the molding composition according to the invention is reduced if it is exposed to heat during molding or is used at high temperatures. The molding composition of the present invention is stable to cracking even when exposed to hot water or steam.
The molding composition according to the invention can therefore be used for the production of many everyday objects.

are applied, using well-known deformation methods, e.g. B. injection molding, extrusion or compression molding, can be applied. Typical examples of end products obtained by molding are Films, monofilaments and injection molded articles such as machine parts, automobile parts, parts of electrical Components, vessels and springs. The molding compound according to the invention is also particularly good as an engineering plastic Suitable for various uses where the excellent properties the aromatic copolyester are required.

The invention is illustrated in the examples. Unless otherwise specified, all parts, percentages, Ratios and the like based on weight.

The inherent viscosity () ,,,,,,) reported in these examples is that at 25 ° C in one Mixture of phenol and tetrachloroethane (weight ratio 6: 4) (C = 1 g / dl) measured value.

The color of the molded article and the occurrence of cracking were visually observed with the naked eye and evaluated as shown below. The evaluation of cracking was carried out after the molding body 120 are h at 80 ⁰ C and a relative humidity of 95% was allowed.

Evaluation of the color:

colorless 1

light yellow 3

yellow 5

light brown 7

brown 9

Evaluation of crack formation:

no cracking A

Occurrence of very little cracking B

Minor cracking occurs C

Occurrence of moderate cracking D

Large cracking occurs E

The Izod impact strength was measured according to ASTM Standard D256 using a notched specimen measured at a width of 0.3 cm on an Izod impact tester.

The high temperature resistance test was carried out in such a manner that a sample was kept at 380 ° C. for 5 minutes was left to stand and then molded in an injection molding machine and then the properties of the obtained molded body were determined.

example 1

450 kg of aqueous sodium hydroxide solution with 22.5 kg of bisphenol A dissolved therein were with 292 kg of a Methylene chloride solution of 10 kg of isophthaloyl dichloride and 10 kg of terephthaloyl dichloride mixed. That The mixture was vigorously stirred to initiate the reaction.

Then the organic layer was separated and washed four times with pure water. When evaporating of the methylene chloride was a powdery polymer with an inherent viscosity (//, ";,) of 0.70 received.

The various additives listed in Table I were added to the powdered polymer in one Amount of 0.1%, based on the weight of the powdery polymer, added and then with it mixed in a super mixer. The mixture was sufficiently dried in vacuo and then made into chips extruded.

The chips were sufficiently dried and then molded into the test samples in an injection molding machine.

The test samples were exposed to 240 hours of air 17O ⁰ C. The changes in color and viscosity were examined. The results obtained are shown in Table I.

The deformation temperature during the production of the sample was 360 ^° C.

Table I.

55 attempt stabilizer Treated at 170 ^° C. for 240 h after High temperature Occurrence of a before the treatment resistance test Crack formation after treatment 'im, color /,/";, Colour 120 hours
Treatment at /"";, Colour 80 ⁰ C and one 60 relative humidity activity of W,

Control none 0.60

1 Tris- (2-chloroethy!) - 0.64 phosphate

2 bis (2-chloroethyl) - 0.65 phosphate

0.55 0.61

0.63

10 5

E B

continuation

attempt stabilizer 240 hr hot 17O ⁰ C treated High temperature Occurrence of a before the after Besländigkeilstest Crack formation after treatment treatment 'im, color 120 hours longer
Treatment at ιιι ,, ι, color '// »* ^color 80 ⁰ C and one relative humidity activity of 95%

Mono- (2-chloro-0.65 3 0.63 4 0.60 5 A.

ethyl) phosphate

Bis- (2-chloroethyl) - 0.67 2 0.66 3 0.63 4 A.

phosphate and

Mono- (2-chlorine-

ethyl) phosphate

(Weight ratio

Dibutyl phosphate 0.63 4 0.60 5 0.58 5 A

Mono- (2-bromo-0.62 5 0.58 6 0.53 6 B

ethyl) phosphate

Monomethyl-0.64 3 0.60 5 0.58 6 B

phosphate

Monoethyl phosphate 0.65 3 0.61 4th 0.60 4th B. Triethyl phosphate 0.64 4th 0.61 5 0.58 5 B. Ditridecyl phosphate 0.66 5 0.57 6th 0.56 6th C. Mono- (2-ethyl-
hexyl) phosphate 0.65 3 0.62 4th 0.62 4th A. Tristearyl phosphate 0.63 4th 0.57 6th 0.54 6th C. Orthophosphorus 0.62 3 0.57 6th 0.55 6th C.

20th

30 35

acid

From the results in Table I it can be seen that test samples made from aromatic copolyesters containing the contain phosphorus-containing compounds as stabilizers, aromatic copolyesters without a stabilizer (Control) in terms of the reduction in viscosity and the prevention of color formation after Treatment, viscosity reduction and prevention of color formation after the high temperature bus flush test and are superior to the prevention of cracking.

Among the phosphorus-containing compounds were the compounds bis (2-chloroethyl) phosphate, mono- (2-chloroethyl-phosphate) and mono- (2-ethylhexyl) phosphate are particularly superior. A pronounced effect was made with a mixture of bis (2-chloroethyl) phosphate and mono- (2-chloroethyl) phosphate in a weight ratio of 1: 1 received.

Example 2

Powdery aromatic copolyester was produced according to Example 1. In addition, powder was a 1: 1 mixture (based on weight) of bis (2-chloroethyl) phosphate and mono- (2-chloroethyl) phosphate in amounts of 0,01,0,1,0,5, 1.0, 2.0 and 5.0 wt% given. The individual mixtures were completely dried to a moisture content of less than 0.01% and then formed into chips in an extruder. As in Example 1, samples were prepared using an injection molding machine. The test samples were exposed to ^{air at 170 ° C. for 240 hours.} The changes in color and viscosity of the test samples were determined. The results obtained are shown in Table II.

Table II

attempt Added amount of one
Mixture of bis- (2-chlorine-
ethyl) phosphate and mono-
(2-chloroethyl (phosphate
(Weight ratio 1: 1) before the
> linh treatment
colour Izod blow
strength after
'/// l / l the treatment
colour Izod blow
lcstigkcit Wt% kg ■ cm / cm ² kg · cm / cm ² control no 0.60 7th 33 0.55 10 9 1 0.01 0.62 4th 35 0.58 5 21 2 0.1 0.66 2 34 0.65 3 30th 3 0.5 0.66 2 37 0.65 3 32 4th 1.0 0.65 3 31 0.62 4th 26th A *) 2.0 0.62 4th 25th 0.59 5 16 B *) 5.0 0.59 4th 13th 0.57 5 4th *) Comparison.

From the results in Table II, it can be seen that test samples made from an aromatic Copolyester with a 1: 1 mixture (based on weight) of bis (2-chloroethyl) phosphate and mono- (2-chloroethyl) phosphate, a test sample made from a stabilizer-free aromatic copolyester the prevention of viscosity reduction and discoloration as well as the Izod impact strength were clearly superior. In particular, when the amount of the stabilizer added was 0.1 to 0.5% by weight, a marked difference was found.

Example 3

To a solution of an aromatic copolyester prepared by interfacial polycondensation using 5.5 kg of an aqueous sodium hydroxide solution with 2.75 kg of bisphenol A dissolved therein, 1.21 kg of isophthaloyl dichloride, 1.21 kg of terephthaloyl dichloride and 25 1 of methylene chloride was added 0.551 of a methylene chloride suspension, which 21.0 g each of a 1: 1 mixture (based on weight) of di- (2-ethylhexyl) phosphate and mono- (2-ethylhexyl) phosphate and a 1: 1 mixture (based on weight) of monobutyl phosphate and dibutyl phosphate. The methylene chloride was gradually evaporated and the residue pulverized, whereby granular aromatic copolyesters containing stabilizers were obtained. Each aromatic copolyester was completely dried, and test samples were prepared therefrom in the same manner as in Example 1. The test samples were each exposed to ^{air at 170 ° C. for 240 hl.} The changes in viscosity and color of the test samples were determined. The results obtained are shown in Table III.

Tabel III Mengc
*) before treatment
at 170 ⁰ C colour ϊ Izod-
Impact
solidifying
speed after treatment
at 170 ° C Color izod-
Impact
solidifying
speed after the RiM training
treatment Crack
bil
manure I zod-
Impact
IcStIg-
speed Ver
search stabilizer kg
cm / cm '/ inh kg- _n
cm / cm * ¹ ImIi kg-
cm / cm 7th 32 10 11 E. 3 0 0.60 2 36 0.55 3 30 0.46 A. 33 Con
troll none 0.2 0.66 0.63 0.60 1 Di- (2-ethylhexyl) -

phosphate and mono- (2-ethylhexyl) phosphate (1: 1 mixture based on weight)

2 monobutyl phosphate 0.2 0.65 2 34 0.64

and dibutyl phosphate (l: l mixture, based on weight)

(*) Weight percent based on the weight of the aromatic copolyester.

0.62 A

From the results in Table III it can be seen that aromatic copolyesters which contain a phosphorus Compound contained and by adding a methylene chloride solution of the phosphorus-containing compound had been obtained to the solution of the aromatic copolyester, also no reduction in viscosity, Discoloration and cracking experienced.

Example 4

A powdery aromatic copolyester was prepared as in Example 1. 20 _parts by weight of polyethylene terephthalate powder (with a> lrel of 1.38, measured in a 5: 5 mixture (based on weight) of phenol and tetrachloroethane) were added to 80 parts by weight of the powder. Furthermore, 0.2 parts by weight of a 1: 1 mixture (based on weight) of di- (2-ethylhexyl) phosphate and mono- (2-ethylhexyl) phosphate were added. The mixture was mixed with a super mixer for 15 extruded in a vacuum at 100 ⁰ C dried and in an extruder with a cylinder temperature of 300 ⁰ C. Test samples were prepared by shaping the resulting scavenger in an injection molding machine at 32O ° C as in Example. 1

The resulting test samples were ^{exposed to air at 80 °} C. and a relative humidity of 95% for 240 hours. The changes in appearance and inherent viscosity were examined. When polyethylene terephthalate is added to the aromatic copolyester, the softening temperature of the mass increased to lOtägigem aging at 170 ⁰ C., and softened the sample. However, in order to make the results consistent with the above examples, aging was carried out under the same conditions as in the above examples. The results obtained are shown in Table IV

Table IV added
Polymer stabilizer before the
'linh treatment
colour after treatment
at 170 ° C
ΊΜ color 10 Appear
a crack
education attempt none none 0.59 7th 0.53 10 E. Control 1 Polyethylene
terephthalate none 0.58 6th 0.51 2 B. Control ii dto. 1: 1 mixture (to the
Weight based) of
Di- (2-ethylhexyl) -
phosphate and mono-
(2-ethylhexyl) phosphate 0.64 1.5 0.61 A. 1

The results of Table IV show that the application of the specific when adding polyethylene terephthalate phosphorus-containing compound the reduction in viscosity, cracking and discoloration in the Compared to the control samples I and II markedly prevented. The common use of the phosphorus Compound according to the invention and of polyethylene terephthalate gave an improved effect for Prevention of discoloration.

Example 5

A powdery aromatic copolyester was prepared as in Example 1. 40 parts by weight of polyethylene terephthalate powder (with an i _lre of 1.38, measured in a 5: 5 mixture (based on weight) of phenol and tetrachloroethane) were added to 60 parts by weight of the powder. Then 0.1 parts by weight of the compounds shown in Table V were added and the mixture was mixed in a super mixer. The mixture was sufficiently dried in vacuo and extruded into chips with an extruder. The chips were sufficiently dried and molded into test samples in an injection molding machine.

The colors and viscosities of the test samples were examined. The results obtained are shown in Table V. compiled.

The deformation temperature for the preparation of the sample was 28O ⁰ C.

I i

Table V

attempt

phosphorus compound, stabilizer

Test sample

Control 1 none

Control II trioctyl phosphite

Control III triphenyl phosphate

1 bis (2-chloroethyl) phosphate and mono- (2-chloroethyl) phosphate
(1: 1 mixture [based on weight])

2 dibutyl phosphate and monobutyl phosphate 0.63 1.5
(1: 1 mixture [based on weight])

0.57 7th 0.58 7th 0.57 7th 0.63 1

The results in Table V show that when polyethylene terephthalate was added to the aromatic copolyester the addition of the specific phosphorus-containing compound as a stabilizer reduces the viscosity and markedly prevented the discoloration. On the other hand, the use of common phosphorus compounds resulted as stabilizers according to control tests II and III, no stabilizing effect whatsoever for the aromatic Copolyester. This confirms that the phosphorus-containing compounds in the molding compositions according to the invention has a pronounced effect in particular for preventing discoloration of the aromatic copolyester exercise.

Example 6 and comparative experiments I to V (submitted later)

An aromatic copolyester powder was prepared in the same manner as in Example 1. 0.1% by weight of each of the phosphorus-containing compounds listed in Table VI below were added to the powder. Each mixture was melt-extruded in a vacuum at 100 ⁰ C for 4 hours under a reduced pressure of 399.9 mbar and then dried at 360 ° C using an extruder to form chips. The resulting chips were in a vacuum at 100 ⁰ C for 4 hours under a reduced pressure of 399.9 mbar and subsequently with an injection molding machine at 360 ⁰ C to form test specimens having a size of 0.32 cm x 1.27 cm x 12.7 cm, shaped.

The logarithmic viscosity numbers, color changes and formation of cracks in the molded articles were evaluated before and after a high temperature treatment at 170 ⁰ C for 720 hours or a wet and heat treatment at 80 ⁰ C and a relative humidity of 95% at 720 hours.

In addition, a high-temperature dwell test was carried out in which the sample was subjected to a for 5 minutes Cylinder temperature of 380 ° C was left to stand. The color changes and the inherent viscosity numbers the molded body after the high-temperature residence was examined.

The results obtained are shown in Table VI below.

Table VI Example no.

Phosphorus compound

before treatment

Color crack b.

after treatment
at 170 ⁰ C during
720 hours

,,, ",, color crack b.

after treatment at 80 ° C, 95% relative humidity
for 720 hours

/ ,, "/, color crack b.

Dwell test at 380 ⁰ C for 5 SId.

Example 6 according to the invention 0.65 3 according to ')

0.64 4

0.60 3

Comparative ² ) Experiment I.

Comparative ³ ) Experiment II

Comparative ") Experiment III

Comparative ⁵ ) Experiment IV

Comparative ⁶ ) Experiment V

0.64 3

0.64 5

0.61 3

0.64 3

0.64 3

A 0.60 5 A 0.55 3

A 0.58 8 A 0.54 5

A 0.54 5 A 0.48 3

0.58 5

0.60 5

0.52 3

0.54 3

A 0.61 4

C 0.55 6

E 0.53 10

E 0.50 6

E 0.53 5

E 0.54 6

10

Remarks:

') Mixture (1: 1 by weight) of di- (2-chloroethyl) phosphate and mono- (2-chloroethyl) phosphate

³ ) Di (3-nonylphenyl) pentaerythritol diphosphite according to DE-OS 26 33 944.

³ ) Di-Q-chloroethylM-chlorophenyl phosphite according to JP-A-23 564/76. ¹⁰

⁴ ) Phosphorous acid according to JP-A-36 753/74.

^s ) Phosphorous acid / triphenyl phosphite <1: 1 weight mixture) according to JP-A-36 752/74. '') l'oly (phenoxy-p-phenylenediphosphite) according to JP-A-23 255/74.

From Table VI it is seen that in the produced from the novel molding compositions moldings no cracking occurred, especially after a 720stündigen treatment at 8O ⁰ C and a relative humidity of 95% (Evaluation A). Slight to severe cracking occurred in the moldings according to the prior art. The discoloration that occurred was also significantly greater in the prior art than in the samples according to the invention. With the samples according to the invention, ratings of 3 or 4, ie light yellow to yellow, were achieved even after longer treatment times at higher temperatures, whereas the corresponding discolorations in the samples according to the prior art go up to a value of 10, which means strong brown . The viscosity values also show the superiority of the molding compositions according to the invention. Thus, the initial viscosity of the samples according to the invention was retained practically over all treatments (values from 0.65 to 0.60), whereas it was greatly reduced in the samples according to the prior art, namely in the order of magnitude from 0.64 to 0.48.

Claims (1)

Patent claims: 1. Molding compound based on (A) an aromatic copolyester which is derived from (a) a mixture of terephthalic acid and / or a functional derivative thereof and isophthalic acid and / or a functional derivative thereof, wherein the terephthalic acid units / isophthalic acid unit molar ratio is about 9: 1 to about 1: 9, and (b) of at least one bisphenol of the general formula I: