GB2023625A - Reinforced polyester moulding composition and its use - Google Patents

Reinforced polyester moulding composition and its use Download PDF

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Publication number
GB2023625A
GB2023625A GB7921709A GB7921709A GB2023625A GB 2023625 A GB2023625 A GB 2023625A GB 7921709 A GB7921709 A GB 7921709A GB 7921709 A GB7921709 A GB 7921709A GB 2023625 A GB2023625 A GB 2023625A
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Prior art keywords
weight
moulding composition
acid
copolyester
polyester
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GB7921709A
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Novartis AG
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Ciba Geigy AG
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    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
    • C08G63/00—Macromolecular compounds obtained by reactions forming a carboxylic ester link in the main chain of the macromolecule
    • C08G63/02—Polyesters derived from hydroxycarboxylic acids or from polycarboxylic acids and polyhydroxy compounds
    • C08G63/12—Polyesters derived from hydroxycarboxylic acids or from polycarboxylic acids and polyhydroxy compounds derived from polycarboxylic acids and polyhydroxy compounds
    • C08G63/16—Dicarboxylic acids and dihydroxy compounds
    • C08G63/18—Dicarboxylic acids and dihydroxy compounds the acids or hydroxy compounds containing carbocyclic rings
    • C08G63/181—Acids containing aromatic rings
    • C08G63/183—Terephthalic acids
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K3/00—Use of inorganic substances as compounding ingredients
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K7/00—Use of ingredients characterised by shape
    • C08K7/02—Fibres or whiskers
    • C08K7/04—Fibres or whiskers inorganic
    • C08K7/14—Glass

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  • Chemical & Material Sciences (AREA)
  • Health & Medical Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Medicinal Chemistry (AREA)
  • Polymers & Plastics (AREA)
  • Organic Chemistry (AREA)
  • Compositions Of Macromolecular Compounds (AREA)
  • Polyesters Or Polycarbonates (AREA)

Abstract

The compositions are based on a mixture containing (a) 95-40% of poly-(1,4-butylene terephthalate modified with 2.5-15 mol% of a C4-40 linear aliphatic dicarboxylic acid and having an intrinsic viscosity of 0.7-1.25 dl/g and (b) 5-60% of a reinforcing filler. The compositions have a high elongation at break and tracking resistance and can be used, in particular, for the production of mouldings for electrical articles.

Description

SPECIFICATION Reinforced polyester moulding composition and its use The present invention relates to a reinforced polyester moulding composition based on copolyesters of poly-( 1 ,4-butylene terephthalate) and the use of the moulding composition for the production of shaped articles for electrical items.
Reinforced poly-( 1 ,4-butylene terephthalate) (PBT) has recently achieved economic significance as a readily processable moulding composition. Despite the fact that overall the spectrum of properties is good, there is a desire for some improvements. Thus, for example, the too low elongation at break of the reinforced PBT is regarded as a defect. As a result of this, the mouldings are not adequately deformable and tend to fracture, which preciudes a number of applications. Due to the relatively low tracking resistance, mouldings made of reinforced PBT are not very suitable in the field of electrical articles.
In German Offenlegungsschrift 2,051,232 a polyester moulding composition is described which consists of homopolyesters and copolyesters of PBT and is distinguished by a high intrinsic viscosity of at least 1.3 dl/g (measured by the method indicated in this Application). Co-components mentioned are, for example, aliphatic dicarboxylic acids, such as azelaic acid. The addition of glass fibres is also mentioned. In the case of these relatively highly viscous reinforced moulding compositions, the poor flow of the melt is regarded as a defect, since, because of the possible premature solidification of the melt, filling of the mould is not ensured. It is therefore difficult to produce thin-walled mouldings.
A special process for the production of copolyesters of PBT with aliphatic dicarboxylic acids such as adipic acid is proposed in German Offenlegungsschrift 2,336,026. Glass fibres can also be added to these moulding compositions. It has been found that the elongation at break of these moulding compositions, which are reinforced with glass fibres and have a relative viscosity of 1.36 (corresponding to an intrinsic viscosity of about 0.65 dl/g according to the method of measurement used here), represents no improvement when compared with that of reinforced PBT.
The object of the present invention is to provide a reinforced polyester moulding composition which is based on copolyesters of poly-(1 ,4-butylene terephthalate) with aliphatic dicarboxylic acids and is distinguished by an increased elongation at break, has a spectrum of mechanical properties which shows only little change compared with that of the homopolyester (PBT) and which is also suitable for the production of thin-walled mouldings. A further object of the present invention is to provide such a moulding composition which is particularly suitable for the production of shaped articles with improved tracking resistance, for electrical items.
The present invention relates to a reinforced moulding composition based on thermoplastic polyesters, which contains (a) 9540% by weight of a linear copolyester of terephthalic acid and 1,4butanediol and 2.5 to 1 5 mop%, based an the polyester, of azelaic acid or the same amount by weight of a linear aliphatic dicarboxylic acid having 4 to 40 and preferably 5 to 40 C atoms and (b) 560% by weight of a reinforcing filler, wherein the intrinsic viscosity of the copolyester is 0.71.25 dl/g, measured at 30"C on a solutipn of 1 g of polyester in 100 ml of a solvent consisting of equal parts of phenol and symmetrical tetrachloroethane.
The intrinsic viscosity is preferably 0.8-1.25 dl/g and especially 0.8 to 1.1 dl/g. (a) 95 to 60% by weight of the copolyester and (b) 5 to 40% by weight of the reinforcing filler, especially glass fibres, are preferred.
The copolyester contains the linear aliphatic dicarboxylic acids in an amount of preferably 3-12 and especially 3-8 mol%. The acids contain in particular 7-36 C atoms and especially 7 to 20 C atoms. Suitable dicarboxylic acids are, for example, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, tefradecanedicarboxylic acid, octadecanedicarboxylic acid and eicosanedicarboxylic acid as well as dimerised fatty acids (dimer acids). Azelaic acid and sebacic acid are preferred.
The copolyesters are prepared by known processes, by transesterification and polycondensation of terephthalic acid, one or more of the aliphatic dicarboxylic acids or their polyester-forming derivatives and 1 ,4-butanediol in the presence of catalysts. A small proportion, for example up to 5 mol%, of the terephthalic acid and/or the butanediol can be replaced by other diols or aromatic dicarboxylic acids.
The known processes of preparation are described, for example, in German Offenlegungsschriften 2,336,026 and 2,651,650.
The moulding composition according to the invention is obtained, for example, by mixing in the reinforcing filler in the requisite amount before or during the polycondensation reaction or during working up of the polyester melt and dispersing it in the polyester. The reinforcing fillers are generally sized. The reinforcing filler can also be dispersed by dry mixing. Preferably, incorporation and dispersion are effected by regranulating a mixture of the copolyester with the reinforcing filler. Examples of suitable reinforcing fillers are asbestos, kaolin, wollastonite, carbon fibres, whiskers and especially glass fibres.
Other inert additives of all types, for example dyes, inorganic and organic pigments, fluorescent brightening agents, delustering agents, mould release assistants and lubricants, stabilisers, antioxidants, crystallisation promotors and flame retardants, can also be added to the reinforcing filler, beforehand or prior to processing. The amount of flameproofing agents added can make up 5 to 25 and preferably 5 to 20% by weight, based on the moulding composition.
Flame retardants are halogen-containing organic compounds, which can be used on their own or together with compounds of the elements of principal group five of the periodic table, especially phosphorus compounds and antimony trioxide. Examples are tetrafluorophthalic anhydride and tetrabromophthalic anhydride, tetrabromobiphenyl ether or decabromobiphenyl ether, hexachlorobiphenyl and especially decabromobiphenyl.
The moulding composition according to the invention is a valuable thermoplastic material, from which moulded articles of diverse types can be produced by the conventional shaping processes, such as casting, injection moulding or extrusion. The mould temperature is generally between 0 and 1 000C and preferably 20 to 800 C and the cylinder temperatures are from 10 to 500C above the melting point of the polyester. Examples of mouldings are profiles and especially technical components. The mouldings surprisingly have a high elongation at break, coupled with mechanical properties which otherwise are only slightly changed. It has also been found that the elongation at break surprisingly decreases again when the intrinsic viscosity is higher than 1.25 dl/g. With regard to the melt flow characteristics, the moulding compositions are processable without problems.
It has also been found, surprisingly, that the tracking resistance of the reinforced copolyester moulding composition is considerably higher than that of reinforced poly-(1,4-butylene terephthalate).
The moulding composition according to the invention is therefore particularly suitable for the production of shaped articles which are used in the field of the electrical industry. Examples are components such as housings and switches in electrical articles, parts for electrical circuits and installations and for car electrical systems. For thicker walled parts, the intrinsic viscosity of the copolyester can be up to 1.5 dl/g.
The use of this moulding composition for the production of shaped articles for electrical items is a further subject of the present invention.
The examples which follow serve to illustrate the invention in more detail. The relative viscosity is determined at 300C on solutions of 1 g of copolyester in 100 ml of a solvent consisting of equal parts of phenol and symmetrical tetrachloroethane.
Examples: I. Preparation Examples for PBT copolyesters Amounts of starting materials: Example A: 18.0 mols of dimethyl terephthalate, 2.0 mols (5 mol%) of dimethyl azelate and 40.0 mols of 1,4-butanediol.
Example B: 18.0 mols of dimethyl terephthalate, 2.0 mols (5 mol%) of dimethyl sebacate and 40.0 molsof 1,4-butenediol.
Example C: 16.2 mols of dimethyl terephthalate, 3.8 mols (9.5 mol%) of dimethyl azelate and 40.0 mols of 1,4-butanediol.
Example D: 16.58 mols of dimethyl terephthalate, 3.42 mols (8.55 mol%) of succinic acid and 40.00 mols of 1 ,4-butanediol.
Example E: 13.16 mols of dimethyl terephthalate, 6.84 mols (17.1 mol%) of succinic acid and 40.00 mols of 1,4-butanediol.
Example F: 17.24 mols of dimethyl terephthalate, 2.76 mols (6.9 mol%) of diethyl adipate and 40.00 mols of 1,4-butanediol.
Example G: 19.28 mols of dimethyl terephthalate, 0.72 mol (1.8 mol%) of dimer acid (Empoi 1010 from Unilever-Emery) and 40.00 mols of 1 ,4-butanediol.
Procedure for carrying out the polycondensation reaction: The starting materials and 1.789 of titanium tetraisopropylate are filled into a 10 1 reactor provided with a stirrer, a nitrogen inlet and a separating column. 98% of the theoretical amount of methanol are distilled off in the course of 4.5 hours, with stirring and whilst passing nitrogen through the mixture, and the temperature of the reaction mixture rises to 2000C.
The mixture is then transferred to a second reactor, co-components in the form of free acids are added and, after these have reacted, a vacuum of 0.5 mm Hg is applied in the course of 1.5 hours and, at the same time, the reaction temperature is raised to 2500C. The increase in the molecular weight can be observed well with the aid of the current input to the stirrer motor (for a constant speed of rotation).
The relationship was determined experimentally beforehand. Co-polyesters with an intrinsic viscosity of up to about 1.0 can be obtained in this way.
The reaction is ended when the particular desired intrinsic viscosity is reached, the melt is extruded through nozzles to give strands and the strands are chilled in water at 1 80C and comminuted to colourless cylindrical granules 2 x 3 mm in size.
The copolyesters with higher molecular weights are prepared by a solid phase condensation reaction. A charge of copolyester prepared by melt condensation as described above is first dried for two hours at 1 400 C under a high vacuum, and crystallised, in a 10 1 Rotavapor flask which dips into an oil bath, and the condensation reaction in the solid phase is then carried out at 2000C until the desired intrinsic viscosity is reached.
II. Use Examples Examples 1-10: PBT copolyesters containing 5 mol% of azelaic acid, which have different molecular weights, are regranulated with 30% by weight of glass fibres with the aid of a single screw extruder at cylinder temperatures of 2500C. In the reinforced state, the granules have the intrinsic viscosity values listed in Table 1. After the moulding compositions have been dried, they are processed to moulded articles by injection moulding, specifically at cylinder temperatures of 2400 C, at a mould temperature of 600 C and with a cycle time of 45 seconds. The properties listed in Table 1 are determined for the moulded articles at room temperature.
It can be seen from these properties that an intrinsic viscosity of at least 0.70 dl/g is required if an adequate elongation at break is to be obtained.
Furthermore, the results show that the deformation at break decreases again with intrinsic viscosities above 1.30 dl/g.
Examples 11-14: A PBT copolyester containing 5 mol% of azelaic acid is reinforced, in the same way as for Examples 1-10, with different amounts of glass fibre. The intrinsic viscosity of the reinforced granules is 0.95 dl/g. The properties listed in Table 2 can be determined at room temperature on moulded articles produced by injection moulding. It can be seen from these properties that the moulding compositions listed are distinguished by a high elongation at break coupled, at the same time, with high tracking resistance.
Examples 15-20: PBT copolyester samples containing 5 mol% of sebacic acid (15), 9.5 mol% of azelaic acid (16),8.55 moi9/o of succinic acid (17), 17.1 mol% of succinic acid (18), 1,8 mol%ofdimer acid (19) and 6.9 mol% of adipic acid (20) are reinforced, in the same way as for Examples 1-10, with 30% by weight of glass fibres. According to Table 3, the reinforced products again possess a high deformation at break coupled, at the same time, with high tracking resistance.
Comparison Example: PBT homopolymer is reinforced analogously to the preceding examples with 30% by weight of glass fibres. The reinforced granules have an intrinsic viscosity of 0.85 dl/g. The elongation at break and tracking resistance of moulded articles produced from these granules are distinctly lower than those of moulded articles produced from the reinforced copolyester moulding compositions.
Table 1 - Properties of glass fibre-reinforced PBT copolyesters containing 5 mol% of azelaic acid (glass fibre content 30% by weight)
Tensile Elongation Impact Modulus of Intrinsic strength at break strength elasticity Example viscosity DIN 53,455 DIN 53,455 DIN 53,453 DIN 53,457 No. (dl/g) (N/mm2) (%) (kJ /m2) (N/mm2) 1 0.48' 85 1.5 17.3 8,500 2 0.54 106 1.7 26.6 8,500 3 0.62 116 2.0 34.1 8,200 4 0.77 106 3;;9 38.7 - 5 0.83 107 4.3 46.3 7,900 0.92 107 4.8 46.4 ~ 7 1.09 113 4.9 47.7 7,900 8 1.34 105 4.8 49.3 9 1.58 103 4.0 48.0 - 10 1.75 104 3.7 48.0 Table 2 - Properties of glass fibre-reinforced PBT copolyesters containing 5 mol% of azelaic acid
Tensile Elongation Impact Modulus of Tracking Glass fibre strength at break strength elasticity resistance Example content (% DIN 53,455 DIN 53,455 DIN 53,453 DIN 53,457 DIN 53,480 No. by weight) (N/mm) (%) (kj/m) (N/mm) KC method 11 5 57 16 47.3 2,200 > 600 12 10 72 5.0 43.5 300 > 600 13 20 100 5.2 45.1 5,400 > 600 14 30 113 4.8 47.4 7,500 > 600 Table 3 - Properties of glass fibre-reinforced PBT copolyesters (30% by weight glass fibre content)
Modulus Tensile Elongation of Tracking Intrinsic Glass fibre strength at break Impact elasticity resistance Example viscosity content (% DIN 53,455 DIN 53,455 strength DIN 53,457 DIN 53,480 No. (dl/g) by weight) (N/mm) (%) DIN 53,453 (N/mm) KC method 15 0.97 30 110 5.0 46.1 7,300 600 16 1.00 30 82 6.8 51 5,300 600 17 1.02 30 100 5.7 42.6 6,200 575 18 1.04 30 68 9.9 48.9 3,600 600 19 0.94 30 114 4.7 42.1 7.800 525 20 1.10 30 106 5.8 43.6 6,300 575 Table 4-Properties of glass fibre-reinforced PBT homopolymer (30% by weight glass fibre content)
Example Tensile Elongation Impact Modulus of Tracking No. strength at break strength elasticity resistance DIN 53,455 DIN 53,455 DIN 53,453 DIN 53,457 DIN 53,480 (N/mm2) (%) (kJ/m2) (N/mm2) KC method Comparison example 133 2.5 40 8,500 300

Claims (7)

1. A reinforced moulding composition based on a thermoplastic polyester, containing (a) 9540% by weight of a linear copolyester of terephthalic acid and 1,4-butanediol and 2.5 to 1 5 mol%, based on the polyester, of azelaic acid or the same amount by weight of a linear aliphatic dicarboxylic acid having 4 to 40 C atoms and (b) 560% by weight of a reinforcing filler, wherein the intrinsic viscosity of the copolyester is 0.71.25 dl/g, measured at 30 C on a solution of 1 g of polyester in 100 ml of a solvent consisting of equal parts of phenol and symmetrical tetrachloroethane.
2. A moulding composition according to claim 1, wherein the intrinsic viscosity is 0.8-1.25 dl/g and especially 0.8-1.1 dl/g.
3. A moulding composition according to claim 1, wherein the copolyester contains radicals of azelaic acid or sebacic acid.
4. A moulding composition according to claim 1, wherein the content of reinforcing filler is 5 to 40% by weight and the composition contains, in particular, glass fibres as the reinforcing filler.
5. A method for the production of shaped articles for electrical items which comprises forming the article from a reinforced moulding composition based on a thermoplastic polyester containing (a) 95-40% by weight of a linear copolyester of terephthalic acid and 1,4-butanediol and 2.5 to 15 mole %, based on the polyester of azelaic acid or the same amount by weight of a linear aliphatic dicarboxylic acid having 4 to 40 C atoms and (b) 5-60% by weight of a reinforcing filler, wherein the intrinsic viscosity of the copolyester is 0.7-1.5 dl/g. measured at 30 C. on a solution of 1 g. of polyester in 100 ml. of a solvent consisting of equal parts of phenol and symmetrical tetrachloroethane.
6. A reinforced moulding composition as claimed in Claim 1, substantially as hereinbefore described with reference to any one of the foregoing Examples.
7. A method as claimed in Claim 5, substantially as hereinbefore described with reference to any one of Examples 11-20.
GB7921709A 1978-06-23 1979-06-21 Reinforced polyester moulding composition and its use Withdrawn GB2023625A (en)

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JP (1) JPS555989A (en)
BR (1) BR7903943A (en)
DE (1) DE2924895A1 (en)
FR (1) FR2429238A1 (en)
GB (1) GB2023625A (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4496713A (en) * 1982-10-25 1985-01-29 Chemische Werke Huels Molding compositions with high toughness and hot-water resistance
WO1991000306A1 (en) * 1989-06-26 1991-01-10 Eastman Kodak Company Novel semi-crystalline polyesters, blends thereof with amorphous polyesters and powder coating compositions based on such blends
EP3323854B1 (en) * 2015-07-16 2021-01-27 Polyplastics Co., Ltd. Polybutylene terephthalate resin composition

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3047990A1 (en) * 1980-12-19 1982-07-15 Bayer Ag, 5090 Leverkusen THERMOPLASTIC BLOCK COPOLYESTER, METHOD FOR THE PRODUCTION THEREOF AND THEIR USE FOR THE PRODUCTION OF MOLDED BODIES
DE4315208A1 (en) * 1993-05-07 1994-11-10 Basf Ag Flame-retardant thermoplastic copolyester molding compounds

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4496713A (en) * 1982-10-25 1985-01-29 Chemische Werke Huels Molding compositions with high toughness and hot-water resistance
WO1991000306A1 (en) * 1989-06-26 1991-01-10 Eastman Kodak Company Novel semi-crystalline polyesters, blends thereof with amorphous polyesters and powder coating compositions based on such blends
EP0408465A1 (en) * 1989-06-26 1991-01-16 Eastman Chemical Company Novel semi-crystalline polyesters, blends thereof with amorphous polyesters and powder coating compositions based on such blends
EP3323854B1 (en) * 2015-07-16 2021-01-27 Polyplastics Co., Ltd. Polybutylene terephthalate resin composition

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BR7903943A (en) 1980-03-25
JPS555989A (en) 1980-01-17
FR2429238A1 (en) 1980-01-18
DE2924895A1 (en) 1980-01-10

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