NL8402629A - Glass fibre reinforced polycarbonates with good flow properties and ha - contain polyalkylene glycol tere- or isophthalates - Google Patents

Abstract

Thermoplastic moulding matls. are comprised of (a) high mol.wt. aromatic polycarbonates (I) based on diphenols, (b) 10-40wt.% (on (a)+(b)) of glass fibres and (c) 5-0.5wt.% (on (a)+(b)+(c)) of a polyalkyleneglycolterephthalate (II), and/or (a) the (I), (b) 10-40wt.% (on (a)+(b)+(c)) of glass fibres and (c) 10-0.5wt.% (on (a)+(b)+(c)) of a polyalkyleneglycolisophthalate (III). The additives (II) or (III) improve the flow props. of the glass reinforced polycarbonate compsn. without noticeably affecting the other props. of the (I), the harness in partic. being fully retained. Pref. (II) is polyethyleneterephthalate or polybutylene terephthalate, and (III) is polyethyleneglycolisophthalate or poly-1,4-bishydroxymethylcyclohexaneisophthalate. Up to 75 mol. % of the isophthalic acid in the (III) may be replaced by other dicarboxylic acids, such as sebacic acid.

Description

I έ 'è, • · ϊ *

NO 32,672 1 J

- Process for the preparation of a thermoplastic molding compound based on a glass fiber-reinforced polycarbonate and an article made of such a molding compound -

The invention relates to a process for the preparation of a thermoplastic molding compound based on a glass fiber-reinforced polycarbonate, by mixing aromatic polycarbonates based on diphenols with 10-40% by weight glass fibers, based on the polycarbonate and the glass fibers, and a polyalkylene phthalate, as well as on an article made of such a molding compound.

Such a method is known from Japanese laid-open patent application 73/60144, in which polybutylene terephthalate in an amount of at least 5% by weight, based on the total mixture, is used to reduce the melt viscosity of the molding composition.

German Auslegeschrift 1,187,793 discloses mixtures of polycarbonates from dihydroxydiarylalkanes and 5-95% by weight of polyalkylene terephthalate, in particular polyethylene terephthalate, which are distinguished by a greatly reduced melt viscosity.

Furthermore, German Offenlegungsschrift 1,694,124 describes mixtures of unreinforced polycarbonates from dihydroxydiarylalkanes with 1-5% by weight of polyalkylene terephthalates, which are distinguished by good stress crack corrosion.

Non-reinforced polycarbonates, on the other hand, show no or only a small improvement in the flow behavior of the melt by adding 0.5-5% by weight of polyalkylene terephthalates.

Surprisingly, it has been found that an added amount of 0.5-10 wt% polyalkylene isophthalates, preferably 1-7 wt%, significantly improves the melt flow behavior of these glass fiber reinforced polycarbonates without affecting the other properties of the polycarbonates be significantly changed; the hardness of the polycarbonates is fully preserved.

34 0 2 β 2 δ S '* NO 32,672 2

The addition of polyalkylene isophthalates also provides better adhesion between the glass fibers and the polymer mixture.

Suitable aromatic polycarbonates are polycarbonates obtained from diphenols with phosgene or the bischlorocarbonic acid esters of the diphenols by the known polycondensation at interfaces. Polycarbonates are also suitable which can be obtained according to the known transesterification process by reacting bisphenol A with diphenyl carbonate. The molecular weights Mw of the polycarbonates to be used according to the invention are between 10,000 and 100,000, preferably between 20,000 and 40,000.

Preferred are polycarbonates based on bis- (4-hydro-xyphenyl) propran-2,2 (bisphenol A), bis- (4-hydroxy 3,5-dichlorophenyl) -propane-2,2 (tetrachlorobisphenol A), bis- (4-hydroxy 3.5 -dibromophenyl) propane-2.2 (tetrabromobisphenol A), bis- (4-hydroxy 3,5-dimethylphenyl) propane-2,2 (tetramethylbisphenol A), bis- (4-hydroxy 3-methylphenyl) -propane-2,2, bis- (4 -hydroxyphenyl) cyclohexane-11 (bisphenol Z), as well as three-nucleus-containing bisphenols such as α1 & β-bis (4-hydroxyphenyl) p-di-sopropylbenzene.

Suitable glass fibers are all types of glass fibers marketed, ie cut glass silk (long and short glass fibers), pre-yarns or staple fibers, provided that the products are sized by suitable means such that the products are compatible with polycarbonates.

The length of the glass wires, whether or not the wires are bundled into fibers 25, should be 60-6 mm for long fibers and 5-0.05 mm for short fibers.

Two types of glass fibers are preferred: 1. Long glass fibers with an average fiber length of 6000 µm, a diameter of 10 µm and a powdery section (less than 30 50 µm) of about 1% by weight and 2. ground short glass fibers with an average fiber length of 230 µm, a diameter of 10 µm and a powdered portion (less than 50 µm) of 5 wt%.

Alkali-free aluminum borosilicate glass 35 "glas glass" or also alkali-containing "C glass" is suitable as glass material.

8402629 * NO 32,672 3

The means known in the literature are suitable as sizing agents; particularly suitable for polycarbonate materials * is the sizing with water known for short glass fibers (see German Auslegeschrift 1,201,991).

5 Further details regarding glass fibers and the use in plastics, in particular polycarbonates, are from Harro Hagen, Glasfaserverstêrkte Kunststoffe, Springer-Verlag,

Berlin, Göttingen, Heidelberg (1961), in particular pp. 182-252 and known from U.S. Pat. No. 3,577,378.

The reinforced polycarbonates can optionally also contain pigments such as, for example, titanium dioxide and the like, other fillers, stabilizers and other additives, without adversely affecting the properties.

Polyalkylene glycol isophthalates according to the invention are known per se polyesters based on aliphatic, cycloaliphatic and araliphatic diols, such as, for example, ethylene glycol, propane 1.3-diol, 2.2-dimethylpropane 1.3-diol, butane 1.4-diol, hexane 1.6-diol, 1.4-bis -hydroxy-methylcyclohexane and bisphenol A-bis-glycol ether, as well as mixtures of these diols.

In the polyalkylene isophthalates according to the invention known per se, the isophthalic acid can be replaced up to a maximum of 75 mol% by aliphatic, cycloaliphatic and aromatic dicarboxylic acids. Suitable aliphatic dicarboxylic acids are, for example, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid; a suitable cycloaliphatic dicarboxylic acid is, for example, cyclohexane dicarboxylic acid-1.4. Examples of aromatic dicarboxylic acids are o-phthalic acid, terephthalic acid, 1,5- and 1,6-naphthalene dicarboxylic acid, 4.4'-, 4.3'- and 3.3f-diphenyldicarboxylic acid, 4.4 *, 4.3 * and 3.3'-diphenylsulfonicarboxylic acid. These dicarboxylic acids can optionally be substituted by alkyl groups or halogen atoms.

The molecular weights of the polyalkylene glycol isophthalates of the invention are 10,000 to 80,000. The polyalkylene glycol isophthalates can be obtained according to the known method from, for example, the dicarboxylic acids or the dialkyl esters thereof and the appropriate diols (see, for example, U.S. Pat. Nos. 8402629 NO 32,672 4

ST C

2,647,885, 2,643,989, 2,534,028, 2,578,660, 2,742,494, 2,901,466).

For example, a low molecular weight alkyl ester of isophthalic acid, preferably the dimethyl ester, is started from, after which the ester is reesterified with the excess diol in the presence of suitable catalysts to the bis-hydroxyalkyl ester of isophthalic acid. The temperature is thereby brought to 210-220 ° C from 140 ° C. The released alcohol is distilled off. The subsequent condensation is carried out at a temperature of 210-280 ° C; the pressure is thereby gradually reduced to less than 1 mm 10 of mercury, whereby the excess of the diol is distilled off.

The molding compositions according to the invention are obtained in the usual manner.

Thus, the polycarbonates together with the glass fibers, the poly-alkylene glycol isophthalates and optionally pigments, stabilizers and other additives can be processed into a homogeneous thermoplastic mass in extruders with one or two axes. Its already reinforced polycarbonate can also be homogenized with the polyalkylene isophthalate in the same way. Another method is the intensive mixing of the components in an internal mixer with subsequent belt granulation.

The mixing time and mixing temperature should be such that copolyester carbonates are not formed to an excessive degree by intermolecular transesterification, i.e. essentially only a physical mixture in which the polymers are evenly distributed. Thus, the mixtures are generally prepared at a temperature of 250-300 ° C, preferably 270-290 ° C. Mixing times should not exceed about 5 minutes at these temperatures.

The molding compositions of a polycarbonate according to the invention are used in areas where a high modulus of elasticity, flexural strength and stiffness and at the same time good toughness are required, such as for instance for all kinds of form-retaining objects, such as cabinet constructions and construction parts.

The examples below further illustrate the method of the invention.

§492629% “NO 32,672 5

Example I

Preparation of polycarbonate.

About 454 parts of 4,4'-dihydroxydiphenyl-2,2-propane and 9.5 parts of p-tert-butylphenol were suspended in 1.5 liters of water. In a 3-necked flask equipped with a stirrer and a gas inlet tube, the oxygen was removed from the reaction mixture by passing nitrogen through the reaction mixture with stirring for 15 minutes. 355 parts by weight of 45% by weight sodium hydroxide solution and 1000 parts by weight of methylene chloride were then added. The mixture was cooled to 25 ° C. While maintaining this temperature by cooling, 237 parts of phosgene were added within 120 minutes. An additional 85 parts by weight of 45% by weight rs sodium hydroxide was added after 15-30 minutes and after the uptake of phosgene had started. 1.6 parts by weight of triethylamine was added to the resulting solution and the mixture was stirred for 15 minutes. A highly viscous solution was obtained, the viscosity of which was controlled by adding methylene chloride. The water-rich phase was separated. The organic phase was washed with salt and alkali-free water. The polycarbonate was isolated from the washed solution and the resulting product was dried. The polycarbonate had a relative viscosity of 1.29-1.30, determined on a 0.5 wt% solution in methylene chloride at 20 ° C. This came with a molecular weight Mw of. about 31000. The resulting polycarbonate was extruded and granulated.

Example II

Preparation of polyethylene isophthalate.

97 parts of isophthalic acid dimethyl ester, 71 parts of ethylene glycol, 0.15 parts of anhydrous calcium acetate and 0.4 parts of antimony trioxide were placed in a round flask equipped with a distillation piece, an air cooler and a gas inlet capillary . Air was removed from the equipment by evacuating and filling with nitrogen. The components were melted by heating at 170 ° C. A weak stream of nitrogen was passed through the capillary. The methanol obtained in the immediately beginning transesterification was distilled off. After about 1 hour, the cleavage of methanol decreased. The temperature was then raised to 200 ° C, after which it was maintained for 2 hours. The remaining methanol was then removed. Then, the excess ethylene glycol was distilled off at 220 ° C, after which the temperature was raised to 270 ° C. At this temperature, the pressure in the device was uniformly reduced to 0.3 mm of mercury, the polycondensation to polyethylene isophthalate taking place with the separation of ethylene glycol. After 3 hours, the conversion was completed. The resulting polyethylene isophthalate had a relative viscosity of 2.01, determined on a 1 wt% solution in a mixture of equal 10 parts by weight of phenol and tetrachloroethane at 25 ° C. This corresponded approximately to a molecular weight Mw of 25,000.

Example III

Preparation of a polybutanediol isoterephthalate from butane 1,4-diol and 40% by weight iso- and 60% by weight terephthalic acid dimethyl ester.

40 parts of isophthalic acid dimethyl ester, 60 parts of terephthalic acid dimethyl ester, 65 parts of butanediol and 0.02 parts of tetraisopropyl o-titanate were placed in a round flask equipped with a distillation piece, an air cooler and a gas inlet capillary. The air was removed from the equipment by evacuation and filling with nitrogen. The components were melted by heating at 160 ° C. A weak stream of nitrogen was passed through the capillary. The methanol obtained in the immediately beginning transesterification was distilled off. After about 1 hour, the separation of methanol decreased and the temperature was kept at 180 ° C for 2 hours. Then the reaction mixture was heated at 200 ° C for 1 hour, removing the remaining methanol. Then, the excess butanediol was distilled off while raising the temperature to 260 ° C and reducing the pressure to 0.3 mm mercury. The reaction mixture was held at said temperature for 45-60 minutes, with the polycondensation to polybu-tanediol isoterephthalate taking place with butanediol splitting off.

The polybutanediol isoterephthalate obtained had a relative viscosity of 2.10, determined on a 1 wt% solution in a mixture of equal parts by weight of phenol and tetrachloroethane at 25 ° C. this corresponded approximately to a molecular weight M1 of 28,000.

8402629

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t 'NO 32,672 7

Example IV

Preparation of a polyethylene softalate sebacate from 90 wt.% Isophthalic acid dimethyl ester, 10 moles. Sebacic acid dimethyl ester and ethylene glycol.

87 parts of isophthalic acid dimethyl ester, 9.2 parts of sebacic acid dimethyl ester, 71 parts of ethylene glycol, 0.15 parts of anhydrous calcium acetate and 0.4 parts of antimony trioxide were converted as in Example II, but the temperature at the condensation was not 280 ° C, but only 260 ° C. The obtained polyethylene isophthalate-10 sebacate had a relative viscosity of 2.30, determined on a 1 wt.% Solution in a mixture of equal parts by weight of phenol and tetrachloroethane at 25 ° C. This corresponded approximately to a molecular weight Mw of 32,000.

Example V - XIV 15 Used polycarbonates.

A. Polycarbonate from example I.

B. Reinforced polycarbonate consisting of 70% by weight of the polycarbonate of Example I and 30% by weight of short glass fibers with a maximum length of about 1 mm.

C. Reinforced polycarbonate consisting of 80% by weight of the polycarbonate based on bisphenol A, prepared according to example I, Μ „.

* 33,000, 20 wt. Long glass fibers about 6 mm in length.

D. Polyethylene Isophthalate from Example II.

E. Polybutanediol Isoterephthalate from Example III.

F. Polyethylene Isophthalate Sebacate from Example IV.

G. Poly-1,4-bis-hydroxymethylcyclohexane isophthalate, Μφ * 39,000, prepared according to Example XII.

The table below shows mixtures and their melt indexes (according to DIN 53 735 at 300 ° C, piston pressure 1.2 kg). The blends were prepared by mixing the components in two-axis extruders.

8402629

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TABLE

Example V VI VII VIII IX TL TL XI

ro art -------; ---- K> Polycarbonate A 100 95 93 - - - -

Polycarbonate E - - - 100 98 94 96

Polycarbonate C - - - - - - -

Polyethylene— - 5 - - 2-- iso-

i'talate D

Polybutane—- - - 7 - - 6 - Diol-Iso /

terephthalate E

Polyethylene: - - - - - - - Φ liso-

phytopathic F

Poly-1.1-bis - - - hydroxymethyl-cyclohexane isophthalate G.

Rockwell hardness - - - 83 82 83 86

M

Elasticity ---. 5830 5810 5840 5790 "modulus [MPa]

Melt index at 3.62 4.04 3.98 1.47 3.47 5.29 4.69 300 ° C according to DIN. 53 735 [g / 10 rain]

Claims (4)

A process for the preparation of a thermoplastic molding composition based on a glass fiber-reinforced polycarbonate by mixing aromatic diphenol-based polycarbonates with 10-40% by weight glass fibers, based on the polycarbonate and the glass fibers, and a polyalkylene phthalate, characterized in that the mixture is made to contain 7-1% by weight of a polyalkylene glycol isophthalate, in which at most 75 mol% of the isophthalic acid can be replaced by other dicarboxylic acids, based on the total mixture. 10 * 2. Process according to claim 1, characterized in that the polyalkylene glycol isophthalate used is polyethylene isophthalate. Process according to claim 1, characterized in that poly-1,4-bis-hydroxymethylcyclohexane isophthalate is used as polyalkylene glycol isophthalate. Article, made wholly or partly of a thermoplastic molding material of a polycarbonate, prepared according to the method of claims 1-3. 8402829 «‘ .........