GB2098231A - Improvements in or relating to polytetramethylene terephthalate- shaped bodies - Google Patents

Abstract

Unreinforced or reinforced polytetramethylene terephthalate- shaped bodies is stabilised with triglycidyl isocyanurate and/or a bisoxazoline, as well as optionally a phenolic or a phosphitic antioxidant. Shaped bodies can be produced from such stabilised polymer, especially by injection moulding, with reduction of the viscosity of the polymer and deterioration of the material properties of the pure polymer itself to any significant extent.

Description

SPECIFICATION Improvements in or relating to polytetramethylene terephthalate-shaped bodies This invention relates to polytetramethylene terephthalate (PTMT) shaped bodies, which may be reinforced or unreinforced and which possess an enhanced property profile as well as improved stability during working, and to a process for the production of such shaped bodies by co-extrusion.

Because of its good use properties and its ease of workability PTMT, as a thermoplastic polyester, has become of some significance as an injection moulding material. However a disadvantage of this polymer is the degradation it undergoes to products with strongly reduced viscosity numbers and deteriorated material properties as a result of the high working temperatures which need to be used when producing shaped bodies from it by working in an extruder and then shaping it by means of for example injection moulding.

This degradation is especially significant when PTMT is reinforced by addition of reinforcing fillers or contains conventional flame protecting agents. The addition of impact resisting agents gives rise likewise to the degradation of PTMT and does not increase the impact and notched bar impact resistance to the expected extent.

This degradation is especially high and obviously to be avoided if reinforcing fillers, flame protecting agents and impact resisting agents are used in combination in PTMT. For many uses PTMT has to be impact resistant at room temperatures and as much as possible at temperatures therebelow.

Such behaviour should not be obtained to the detriment of the high rigidity and resistance to bending generally required of PTMT.

It has already been proposed to improve the notched bar impact resistance of unreinforced PTMT by compounding it with polyethylene or ethylene/vinyl acetate copolymers (German Offenlegungsschrift 28 55 512), with polybutadiene onto which has been grafted styrene and methyl methacrylate (U.S. Patent 3,919,353), with a copolymer of butyl acrylate and tricyclodecenyl acrylate Onto which has been grafted styrene and acrylonitrile or a copolymer of butyl acrylate, butadiene and methylvinyl ether onto which has been grafted styrene and acrylonitrile (German Auslegeschrift 24 44 584), with an ethylene/vinyl acetate copolymer on to which has been grafted acrylic acid or an ethylene/butyl acrylate copolymer onto which has been grafted acrylic acid (German Offenlegungsschrift 24 54 002), with a polyethylene onto which has been grafted butyl acrylate or acrylic acid and butyl acrylate, with an ethylene/propylene copolymer onto which has been grafted butyl acrylate or styrene and acrylonitrile (German Offenlegungsschrift 29 02 468) or with a multiplestep polymer based on butyl acrylate, methyl acrylate and ethyl acrylate as well as optionally styrene graft cross-linked by allyl methacrylate or butylene diacrylate (German Offenlegungsschrift 27 26 256).

The effect achieved for reinforced PTMT with respect to notched bar impact resistance is however small, that is to say the improvement in notched bar impact resistance amounts only to about 1 to 3 units from 9 to 11 KJ/m2, and is accompanied by a significant drop in the mechanical and thermal properties and in particular a drop in both the stiffness and Youngs modulus values.

There is, in particular no teaching in prior art documents as to how impact resistance and notched bar impact resistance can be effectively improved with reinforced PTMT. The stabilisation of PTMT and its stability on working up is moreover insufficient, and the aforementioned drop in molecular weight as a result of degradation is very significant.

From the foregoing, it will therefore be appreciated that there has existed a need to produce PTMT-shaped bodies having high impact and notched bar impact resistance, especially when reinforced, whose usual properties are good, and which additionally undergoes no significant reduction in nominal molecular weight during working. Such bodies thus need to possess good material properties, in general. Moreover the impact resisting effect should be achieved with small additive amounts.

Since PTMT is combustible and imflammable, an increasing amount of reinforced and unreinforced PTMT needs to be rendered flame resistant. However the usual monomeric brominecontaining flame protective agents have been found to be not very suitable for this purpose.

The flame protecting agent must withstand temperatures of 240 to 2800C in the extrusion and injection moulding working. When working PTMT which contains a flame protecting agent, presumably because of the effect of shearing forces, degradation of the PTMT occurs so that the final injected bodies of PTMT are of significantly lower molecular weight than the starting PTMT employed for the extrusion, as a result of which a product having inferior mechanical properties, especially lower strength, than expected results.

The mechanical properties are also unsatisfactory when Sub203 is present as synergist for the flame protecting agent.

This deterioration of the mechanical properties has meant that it has not hitherto been possible to produce an unreinforced PTMT which is both flame resistant and has satisfactory mechanical properties. In particular the impact resistance and above all the elongation at break were very strongly influenced. Thus for example commercially available PTMT products which contain flame protecting agents as aforesaid have an impact resistance so far that test samples show between 25% and 100% break in comparison to "not broken" for pure PTMT test samples and the elongation at break lies between 12% and 17% (in comparison with more than 180% for pure PTMT, that is PTMT worked up in like manner without flame protecting agent).For reinforced PTMT the drop in mechanical strength values caused by the presence of a flame protecting agent is likewise very disadvantageous, there being a fall in the impact resistance from 36 to 25-30 KJ/m2 and in notched bar impact resistance from 9 to 10 to 5-7 KJ/m2 in contrast to pure PTMT.

Moreover, because such flame protected PTMT-shaped bodies have a lower stability during working and use than reinforced PTMT or reinforced PTMT which is not flame protected there is much scope for problems in the event of for example a breakdown in the injection moulding working, too long residence in the injection moulding machine, unsuitable machine adjustment or use of temperatures higher or lower than those ascertained as optimal. In such cases, there is immediately obtained a further reduction in molecular weight and products with further deteriorated mechanical properties are obtained.

Such flame protected, but mechanically deteriorated products will generally be unusable. In the use test with storage of the extrudates for 3 days at 1 500C in air it is observed that the impact resistance can drop to below 50 KJ/m2 at 100% break, the notched bar impact resistance to below 3 KJ/m2 and the elongation at break to below 10%. Moreover, a complete embrittlement of the product is obtained under the test conditions.

It has previously been proposed to stem the reduction of the molecular weight degradation by PTMT-shaped bodies by adding to the PTMT a polymeric epoxy resin of equivalent weight 300 to 2000 g/mol in amounts between 0.5 and 20% (German Offenlegungsschrift 2821 292). In this way there is achieved an improvement in molecular weight, but Tired is still only 1.21-1.41 dl/g in the injection moulding in contrast to Tired=1 .53 dl/g in pure PTMT and this is insufficient for the compounding.

Ti-Ti (#red=/#.1/c wherein #=viscosity of the solvent phenol/o-Dichlorobenzene=60/40, #=viscosity of the solution and c=concentration of the solution in g/1 00 ml).

Moreover, the suitability for use, the results obtained in the use test carried out on the final extrudate and the Tired value in the extrudate also remain unsatisfactory if, according to German Offenlegungsschrift No. P 28 21 292, resins, PTMT, polypentabromobenzyl acylate and Sb2O3 are employed together (see Table 6, Comparative Examples H and J).

There exists therefore the need also to provide conveniently an unreinforced or reinforced PTMT which contains only a small amount of flame protecting agent and of impact resisting agent of the aforementioned co- or graft polymeric type, and which after extrusion and injection moulding possesses comparable mechanical and special properties to injection moulded products formed of pure PTMT or pure PTMT provided only with reinforcing fillers as additives.

More particularly, in general, there is a need to be able to provide PTMT simultaneously with a number of special types of additives to impart reinforcement, impact resistance and flame protection to it, whiie avoiding the degradation or strong deterioration of the good material properties of PTMT which usually takes place when additives are incorporated therein.

According to the present invention, there is provided a polytetramethyleneterephthalate shaped body which is formed of polytetramethylene-terephthalate and contains triglycidyl isocyanurate and/or a bisoxazoline as stabiliser.

It has been found the use of quite specific stabilisers, namely triglycidyl isocyanurate and/or a bisoxazoline, for example the phenylene or tetramethylene isoxazoline leads to suppression of the aforementioned undesirable phenomena. The effect of these stabilisers is particularly surprising since stabiiisers of other type do not hinder the degradation of PTMT and do not lead to maintenance of the special material properties of PTMT.

The present invention will now be described in detail with reference to four types of additives which may be present in polytetramethylene terephthalate shaped bodies, namely (1) reinforcing fillers, (2) impacting resisting agents, (3) phenolic or phosphitic antioxidants and (4) flame protecting agents, which may be used alone or in combination.

Thus this invention is applicable, not only to unreinforced PTMT shaped bodies but to reinforced PTMT-shaped bodies, especially such bodies when reinforced with glass fibres. Preferably from 1 5 to 80% by weight of reinforcing fillers, related to PTMT are present.

Glass fibres have the advantage of possessing a so-called active reinforcing effect. Otherwise it is possible to use, for example asbestos fibres or organic polymer fibres, for example high melting polyester, polyurethane, polysulphone, aliphatic or aromatic polyamide fibres as reinforcing fillers.

Moreover this invention provides shaped polytetramethylene terephthalate bodies with contents of co or graft polymers of ethylene and vinyl acetate or co- or graft polymers based on acrylic acid or methacrylic acid esters as impact resisting agents. The impact resisting agents in the form of the co- or graft polymers are preferably added in amounts of 5 to 30, more preferably 12 to 25% by weight related to PTMT.

This invention also provides PTMT shaped bodies which contain flame protecting agents based on polymerised bromine-containing acrylates or methacrylates and optionally also the aforementioned impact resisting agents.

The stabilisers surprisingly cause the molecular weight drop on working in the extruder and in the subsequent injection mould to be reduced very much; even when using small amounts of the additives, can the degradation of PTMT be suitably influenced. The largely hindered degradation of PTMT on use of the shaped bodies is valuable. The hydrolysis of PTMT on standing in the ambient atmosphere is almost completely held back. The impact resisting agents are only effective as a result of the stabilisers added according to the invention. Moreover, as a result of the presence of the stabilisers flame protecting agents based on high polymerised bromine-containing acrylates which are solid materials, lead to only slight degradation.

The addition of ethylene/vinyl acetate co- or graft polymers is especially valuable taken together with reinforcing fillers. Of especial value are such PTMT bodies reinforced with glass fibres consisting of: a) 45-83, preferably 55-71 parts by weight PTMT with a reduced specific viscosity Tired of 1.2-2.2 dl/g preferably 1.5-1.9 dl/g, (Tired is defined as previously indicated).

b) 1 40, preferably 25-35 parts by weight glass fibres, c) 2-20, preferably 4 10 parts by weight of ethylene/vinyl acetate copolymers or graft polymers (EVA) d) 3-30, preferably 1020% by weight of co-or graft polymers based on acrylic acid esters or methacrylic acid esters.

Furthermore, unreinforced shaped bodies can also be produced, containing 85 to 98% by weight PTMT and 2 to 15% by weight EVA and/or 3 to 30% by weight flame protecting agent which is a polymerised bromine-containing acrylate or methacrylate.

It is surprising that the aforementioned comparatively small arnounts of EVA are sufficient. No further increased impact resistance can be achieved with larger amounts of EVA.

Suitable copolymers of ethylene and vinylacetate are those with contents of vinyl acetate of 2 to 65% by weight, preferably 5 to 50% by weight. The copolymers are known materials and can be produced by copolymerisation in suspension or in bulk. They are generally used in powder form.

By the terms co- or graft polymers based on acrylic acid esters or methacrylic acid esters are understood those polymers in which at least 5% by weight, preferably from 10% by weight of an acrylic acid and/or methacrylic acid ester with 1 to 10, preferably 1 to 6 carbon atoms in the alcohol group of the ester, are present. The second component of the such polymers is preferably another of the indicated acrylic or methacrylic acid esters of a different type of polymerisable olefinic compound such as for example an olefin, acrylonitrile or styrene. In the case of ternary polymers, there will be a further one of the indicated monomers-in the case of graft polymers a graft substrate of two of the components or of butadiene-styrene and preferably an acrylic acid or methyacrylic acid ester is present as grafting agent.Preferred are mixed polymers of 20 to 50, preferably 30 to 40% by weight of an acrylic or methacrylic acid methyl or ethyl ester and a further acrylic or methacrylic acid propyl to butyl ester as well as ter- and graft polymers of 5 to 40, preferably 10 to 30% by weight of an acrylic or methacrylic acid ester, especially a methyl ester, and 40 to 80, preferably 50 to 70% by weight butadiene and 5 to 35, preferably 20 to 30% by weight styrene.

The combined effect of the stabilisers and the impact resisting co- or graft polymers is surprising for in the absence of the claimed stabilisers, co- or graft polymers (comparative examples A to G) achieve practically no improved impact or notched bar impact resistance in comparison with the basic material. In addition to improving the notched bar resistance, the addition of the stabilisers achieves an increase in the elongation at break and the Youngs modulus.

Furthermore the stabilisers affect favourably the temperature stressing to which the material can be subjected during working and increases in particular the working range, that it makes possible the use of a greater temperature range in the extruder or in the injection moulding machine without harming and loss of the composition. Stabilisers of other type do not achieve this synergistic composite effect.

The stabiliser(s) is/are preferably used in an amount of 0.1 to 2.5, more preferably 0.1 to 1.5% by weight based on the weight of PTMT. Insofar as triglycidyl isocyanurate is used alone, an upper limit of 1.0% by weight is preferably placed on the amount added; insofar as p- or m-bisoxazoline is used, its quantity preferably amounts to not more than 1.5% by weight.

It is preferred to add as well a phosphitic antioxidant and a phenolic antioxidant additional to triglycidyl isocyanurate and/or the bisoxazoline. In general, it is feasible for only one of the two antioxidants to be added.

Phosphitic antioxidants are phosphites of at least tri-functional alcohols, especially of pentaerythritol, or for example of trimethylolpropane or possibly even glycerol, wherein one or two of the OH-groups of the phosphoric acid are esterified with a fatty alcohol residue, especially a Cs to C24 fatty acid residue, preferably the stearyl residue or the decyl residue. The preferred alcohol is pentaerythritol.

Phenolic antioxidants will generally be of the type in which there is a sterically hindered phenolic group, especially one containing a t-butyl group in the o-position to the phenolic OH-group. Examples of such anti-oxidants are many. Preferred examples are, however, 2,2'-thiodiethylbis-[3-(3,5-di- tert.butyl-4-hydroxyphenyl)j-propionate and 1 ,3,5-tri methyl-2,4,6-tri-(4-hydroxy-3 ,5-di- tert.butyl)benzene.

Triglycidyl isocyanurate and one of the bisoxazolines achieves, alone or together, a decisive improvement in the mechanical properties, although the added amount is small. The reduced viscosity 77red of the PTMT in the injection mould after extrusion and working is surprisingly equally high or even higher than that of the pure PTMT starting material.

Moreover the two above-indicated types of antioxidant improve very much the scope for working, the stability in use for example as measured in the indicated use test, as well as the colour of the product; that is discolouration is avoided.

In general, when using antioxidants in the production of shaped bodies, it is preferred to use from 0.02 to 0.5, more preferably 0.05 to 0.3% by weight 2,2'-thiodiethyl-bis-[3-(3,5-ditert.butyl-4- hydroxyphenyl)j-propionate and/or 0.05 to 0.5, more preferably 0.1 to 0.3% by weight distearyl pentaerythritol phosphite, especially with the aforementioned amounts of the stabilisers. When an impact-resisting agent and/or a flame protecting agent is present the amount of the 2,2'-thiodiethylbis [3-(3,5-ditert.butyl-4-hydroxyphenyl)]-propionate is preferably 0.02 to 0.3, more preferably 0.05 to 0.2% by weight. These percentages are based on the weight of PTMT.

In the production of reinforced PTMT use is preferably made of PTMT with 11red=1 .2 to 1.3, since here a PTMT of ?1red=1 . to 1.7, which is not only further condensed, but is also more expensive, brings no essential advantage. For unreinforced PTMT, in contrast, PTMT of Tired=1 .6 and higher is preferred.

Reference has already been made herein to the application of this invention to unreinforced or reinforced PTMT-shaped bodies containing flame protecting agents which are polymerised bromine containing acrylates or methacrylates.

While some acceptable losses in impact resistance, notched impact resistance and elongation at break, are obtained when using such flame protecting agents, it is possible as a result of stabilisation according to the invention to produce a satisfactory unreinforced flame protected PTMT based on PTMT-1 .2, that is Tired=1 .2 (Examples 21 and 22) when, without stabilisation or with addition of bisphenol-A-diglycidyl ethers, a complete injection moulding is obtained which is a completely unusable material for constructional uses.

As polymeric, bromine-containing acrylates, there can be used homo- and copolymers containing units of the formula

wherein X signifies preferably bromine, optionally with proportions of chlorine, p the degree of polymerisation, n=0 or 1, Y denotes Br or H3 and R hydrogen, methyl, ethyl or propyl. The production of such polymers is known from German Auslegesschrift 25 27 802. It is also possible to use polymers of such type obtained from the monomers of German Offenlegungsschrift 28 00 020, polymers and copolymers according to German Offenlegungsschrift 26 12 843 as well as copolymers according to German Offenlegungsschrift 26 48 969, and the corresponding bromine-containing acrylates of benzylic alcohols or xylylene glycols.It is preferred, however, to use the especially simply preparable PBB-PA, that is polymers of pentabromobenzyl acrylate, optionally with proportions of tribromo or tetrabromobenzyl acrylates. In addition to the aforementioned acrylates, the corresponding methacrylates can be used, on the basis of comparability, if where in the examples PBB-PA is given as a flame protective agent, a correspondingly good flame protecting effect is achievable with the other known bromine-containing polymeric acrylates, especially if the bromine content approximately equals that of PBB-PA. The flame protecting agent is preferably used in amounts of 5 to 20% by weight related PTMT.

Sb2O3 can be used as synergist to the flame protecting agent in amounts of from 1 to 10% by weight related to PTMT.

In testing for the extent of flame protection achieved, as in the examples which follow, the 1.6 mm flat rods required according to UL 94 (Underwriters Laboratories, subject UL 94) and LOI (lowest oxygen index, that is the O2 proportion in an O2/N2 mixture in volume % which acts just selfextinguishingly) are produced on an injection moulding machine made by the ARBURG COMPANY.

The general mechanical properties were determined according to the following test specifications: Impact resistance DIN 53 453 Notched bar impact resistance DIN 53 454 Bending resistance (limit of bending stress) DIN 53 452 Tensile strength (stretching stress) DIN 53 455 Resistance to tearing DIN 53 455 Elongation at break Thermal non-deformability according to ISO/R 75;A+B DIN 53 461 Table 6 to be set out hereinafter shows the high stability in use of the stabilised flame protected PTMT compositions according to the invention in comparison with the state of the art as expressed by Comparative Examples H (without stabiliser) and J (with an epoxide, EP GY 250 of CIBA GEIGY as stabiliser), testing being carried out in the ambient atmosphere for storage over different times and with subsequent measurement of the changes with time of impact resistance, notched bar impact resistance and elongation at break.

In the production of shaped bodies or compositions embodying this invention, the dry constituents thereof are mixed well and co-extruded by means of an R 45-single screw extruder of the REIFENHAUSER COMPANY in a temperature region of 240 to 2600 C. The extruded strand is withdrawn through a water bath and granulated. After the drying of the granulate, test rods are produced on an injection moulding machine of the firm KRAUSS-MAFFEI in a universal shape which is necessary for the testing of the mechanical and thermal properties.Operating in this way it has quite surprisingly been shown that the shaped bodies, irrespective of whether one or more of the optionally present components reinforcing filler, impact resisting agent, and flame protective means are present, are produceable merely by co-extrusion and are obtained completely homogeneous for the purpose of working up by for example injection moulding. Accordingly, in the simplest conceivable manner, each constituent can be supplied to the extruder as powder or granulate using a suitable metering arrangement.

The stabilisers and antioxidants and Sb2O3 may merely be dusted or sprinkled onto one of the components or are mixed therewith, although that is also not always essential.

Such a co-extrusion is quite unusual since generally through mixing gives rise to some problems and overall addition is then essentially by premixing or double extrusion. In fact the co-extrusion which can be carried out in producing the shaped bodies of this invention reduces essentially the degradation of the PTMT.

Thus, this invention also provides a process for the production of PTMT shaped bodies according to this invention, which comprises continuously supplying to an extruder polytetramethylene terephthalate, triglycidyl isocyanurate and/or a bisoxazoline and optionally one or more further components of the body, which component(s) is/are chosen from a said reinforcing filter, said impact resisting agents and said polymerised bromine-containing acrylate or methacrylate flame protecting agent, which component(s) is/are supplied separately from one another and separately from the polytetramethylene terephthalate, the triglycidyl isocyanurate and/or bisoxazoline and, if used, the phosphitic or phenolic antioxidant and/or Sub203 being simultaneously supplied continuously and separately from one another to the extruder either together with the polytetramethylene terephthalate or one or more of said components or as materials supplied separately from any other constituent(s) of the body, and co-extruding said constituents in the extruder.

This procedure may, in principle, be used when producing reinforced and unreinforced PTMT shaped bodies, which even contain no impact resisting co- or graft polymers of the indicated type or flame protecting agent, and the only additives are for achieving stabilisation with the indicated stabiliser system of triglycidyl isocyanurate and/or bisoxazoline and the optional addition of phosphitic antioxidants and/or phenolic antioxidants which is itself of high value.

The amounts of the stabilisers and antioxidants added are therefore essentially the same in general, irrespective of what further constituents are present, and in the preferred region which has already been given.

The degradation which usually takes place as a result of the essentially high working temperatures of 230 to 2700C in the production of the shaped body by extrusion and then working and shaping by for example injection moulding, with the consequence of lower molecular weight of viscosities and strongly reduced properties in use is prevented essentially by the use of the aforementioned stabiliser system without which cross-linking of the PTMT occurs.

In contrast to when using unstabilised PTMT, the stabiliser system achieves a preservation of important and valuable mechanical properties of the PTMT starting material, such as for example the impact resistance and/or notched bar impact resistance. This widens the scope for working of PTMT. In particular, the improvement in the melt stability of the PTMT under working conditions means that thermal deterioration of the PTMT as a result of disturbances and delays in the working or prolongation of the heating time is minimised. The thermal-oxidative degradation during working and consequential discolouration of the product are therefore largely reduced.

In particular, the retention of stability in use as a result of the stabilisation system has been shown in a test in air at 1 800 C. This test shows that the impact resistance is maintained at "not broken" with unstabilised PTMT for only a few days, whereas with stabilised samples after 10 days the impact resistance has the value not broken and the notched bar impact resistance is likewise reduced only slightly after about 10 days. In a similar manner, a PTMT shaped body reinforced with glass fibres exhibits only a small reduction in the impact resistance and notched bar impact resistance when subjected over many days to thermal stressing.

A further important effect is the stabilisation with respect to hydrolysis which can be checked by hot water storage of injection mouldings at 800C. Here, the test shows that the original impact resistance, notched bar impact resistance and elongation at break with unstabilised samples is only maintained for about 4 weeks, whereas the original values of impact resistance and notched bar impact resistance are maintained for about 12 weeks in the hydrolysis test carried out on the stabilised samples. This applies in particular for unreinforced PTMT; the effect of stabilisation of PTMT with glass fibre reinforcement is not quite so impressive.

The following Examples illustrate this invention. In the examples all parts are on a weight basis.

Examples 1 to 22 In each of these examples, and the associated Comparative Examples, to produce the indicated PTMT composition, the dry components were premixed well and co-extruded through a single screw extruder with a screw diameter of 45 mm in the temperature range 240 to 2800 C. The extruded strand was withdrawn through a water bath and granulated. After the drying of the granulate, the injection mouldings required for the testing of the mechanical and thermal properties were produced on an injection moulding machine of the firm KRAUSS-MAFFEI in a universal mould.

Examples 1 to 3 and Comparative Example A use ethylene-vinyl acetate copolymer (EVA) with 18% by weight vinyl acetate, Examples 4 and 5 as well as Comparative Examples B to D the same but with 7.5% by weight vinyl acetate. GF denotes glass fibre. The impact resisting graft polymer Ml consists of about 20% by weight methylmethacrylate, about 60% by weight butadiene and about 20% by weight styrene. the mixed polymer M2 consists of about 65% by weight n-butyl acrylate and about 35% by weight methyl methacrylate.

Moreover, in the Examples, the reference letters I) to VII) have the following means: I) 2,2'-Thiodiethylbis-3-(3,5-ditert.butyl-4-hydroxyphenyl)-propionate II) Distearyl pentaerythrityl phosphite Ill) Triglycidyl isocyanurate IV) p-phenylenebisoxazoline V) 17red=sp/c (1% in Phenol/O-Dichlorobenzene=60/40) VI) Araldite GY 250 CIBA-GEIGY (Epoxide-equivalent weight about 180-190 g/mol Epoxide) VII) Epikote 1001 of SHELL COMPANY The PTMT samples used in the examples are denoted by reference letters as follows: : For PTMT-A, Tired=1 .76 dl/g PTMT-B, Tired=1 .67 dl/g PTMT-C, Tired=1 .6 dl/g PTMT-D, x7red= 1.2 dl/g Other abbreviations appearing in the examples are B=broken NB=not broken Table 1 Example 1 Example 2 64 parts PTMT-A 60 parts PTMT-A Comparative 30 parts GF 30 parts GF Example A 6 parts EVA 10 parts EVA 64 parts PTMT-A Stabilises Stabilises 30 parts GF 0.1 part I) 0.2 part II) 6 parts EVA +0.2 part II) +0.2 part II) without +0.4 part III) +0.5 part III) Stabiliser Impact Resistance KJ/m2 46 49 36 Notched bar impact resistance:: 230C KJ/m2 24 25 14 -20 C KJ/m2 18 20 11 -40 C KJ/m2 17 18 10 Tear resistance N/mm2 124 119 110 Youngs Modulus (Drawing test) N/mm2 9400 8800 7600 Limit of bending test N/mm2 190 182 173 Thermal non-deformability according to ISO/R75:A C 186 178 172 ISO/R75:B C > 200 > 200 > 200 Ball pressure hardness N/mm2 151 Table 1 (continued) Example 3 Example 4 Example 5 66 parts PTMT-A 64 parts PTMT-A 60 parts PTMT-A 30 parts GF 30 parts GF 30 parts GF 4 parts EVA 6 parts EVA 10 parts EVA Stabiliser: Stabiliser:Stabiliser: 0.1 part 1) 0.1 part 1) 0.2 part I) +0.2 part 11) +0.2 part 11) +0.3 part 11) +0.6 part 111) +0.4 part III) +0.4 part III) Impact Resistance KJ/m2 44 47 48 Notched bar impact resistance: 230C KJ/m2 19 23 26 -20 C KJ/m2 16 17 18 -40 C KJ/m2 14 15 17 Tear resistance N/mm2 129 126 115 Youngs Modulus (Drawing test) N/mm2 9800 9700 8600 Limit of bending test N/mm2 187 196 182 Thermal non-deformability according to 1S0/R75:A C 192 190 lSO/R75:B C > 200 > 200 > 200 Ball pressure hardness N/mm 164 159 149 Table 1 (continued) Comparative Comparative Example D Example B Comparative 70 parts PTMT-A 60 parts PTMT-A Example C 30 parts GF 30 parts GF 70 parts PTMT-A Stabiliser:: 10 parts EVA 30 parts GF 0.1 part 1) Without Without +0.2 part II) stabiliser stabiliser +0.5 part III) Impact Resistance KJ/m2 38 35 37 Notched bar impact resistance: 230C KJ/m2 13 9-10 9-11 -20 C KJ/m 12 -40 C KJ/m2 11 8-9 8-10 Tear resistance N/mm2 112 130 133 Youngs Modulus (Drawing test) N/mm2 6700 10000 10500 Limit of bending test N/mm2 164 190 200 Thermal non-deformability according to ISO/R75:A C 168 200 ISO/R75: B C > 200 > 200 Ball pressure hardness N/mm2 - 175 Table 2 Example 6 Example 7 Example 8 85 parts PTMT-A 88 parts PTMT-A 82 parts PTMT-A 15 parts M, 12 parts M1 18 parts M, Stabiliser: Stabiliser:Stabiliser: 0.1 part 1) 0.1 part I) 0.2 part I) +0.2 part II) +0.2 part II) +0.3 part II) +0.5 part III) +0.6 part III) +0.4 part III) Impact resistance KJ/m2 without break without break without break Notched bar impact resistance: 230C KJ/m2 44 32 47 -20 C KJ/m2 18 14 19 -40 C KJ/m2 14 11 16 Tensile strength N/mm2 43 45 42 Resistance to tear N/mm2 30 32 32 Elongation at break % 125 107 140 Bending resistance N/mm2 69 72 65 Youngs Modulus (from bending experiment) N/mm2 1900 1980 1850 Thermal non-deformability according to ISO/R75:A C 55 56 51 ISO/R75:B C 151 154 143 Table 2 (continued) Example 9 Example 10 85 parts PTMT-A 82 parts PTMT-A 15 parts M1 18 parts Mr Stabilises Stabiliser:: 0.1 part!) 0.1 part I) +0.2 part II) +0.2 part11) +0.4 part IV) +0.5 part IV) Impact resistance KJ/m2 without break without break Notched bar impact resistance: 230C KJ/m2 45 48 -200C KJ/m2 17 -400C KJ/m2 13 Tensile strength N/mm2 44 40 Resistance to tear N/mm2 30 29 Elongation at break % 130 115 Bending resistance N/mm2 64 61 Youngs Modulus (from bending experiment) N/mm2 1750 1700 Thermal non-deformability according to ISO/R75:A C - ISO/R75:B C - Table 2 (continued) Comparative Comparative Example E Example F 85 parts PTMT-A 82 parts PTMT-A 15 parts M1 18 partsM1 without without Stabiliser Stabiliser Impact resistance KJ/m2 without break without break Notched bar impact resistance:: 230C KJ/m2 12 16 -200C KJ/m2 8 10 -400C KJ/m2 6 7 Tensile strength N/mm2 42 39 Resistance to tear N/mm2 28 27 Elongation at break % 35 30 Bending resistance N/mm2 57 55 Youngs Modulus (from bending experiment) N/mm2 1500 1450 Thermal non-deformability according to ISO/R75:A C 53 ISO/R75:B C 145 Table 3 Example 11 Example 12 85 parts PTMT-B 80 parts PTMT-B 15 parts M2 20 parts M2 Stabiliser:Stabiliser: 0.1 part 1) 0.1 partI) +0.2 partII) +0.2 partII) +0.4 part IV) +0.6 part IV) Impact resistance KJ/m2 without break without break Notched bar impact resistance: 230C KJ/m2 23 26 -20 C KJ/m2 9 11 -400C KJ/m2 7 8 Tensile strength N/mm2 43 41 Resistance to tear N/mm2 29 28 Elongation at break % 60 65 Bending resistance N/mm2 70 57 Youngs Modulus (from bending experiment) N/mm2 1950 1850 Thermal non-deformability according to ISO/R75:A C 54 52 lSO/R75:B C 148 137 Table 3 (continued) Example 13 85 parts PTMT-B Comparative 15 parts M2 Example G Stabiliser: 85 parts PTMT-B 0.2 partI) 15 parts M2 +0.2 part II) without +0.5 part III) stabiliser Impact resistance KJ/m without break without break Notched bar impact resistance: 23 C KJ/m 21 14 -20 C KJ/m - -40 C KJ/m - 5 Tensile strength N/mm2 44 44 Resistance to tear N/mm2 30 29 Elongation at break % 50 26 Bending resistance N/mm2 71 56 Youngs Modulus (from bending experiment) N/mm2 1970 1800 Thermal non-deformability according to ISO/R75: A C 55 55 ISO/R75:B C - 136 Table 4 Unreinforced PTMT-compositions Example 14 Example 15 Example 16 86 parts PTMT-C 86 parts PTMT-C 86 parts PTMT-C 10 parts PBB-PA 10 parts PBB-PA 10 parts PBB-PA 4 Sb203 4 parts Sb203 4 parts Sb203 Stabiliser: Stabiliser:Stabiliser: 0.1 part l) 0.1 part l) 0.1 part I) +0.2 part 11) +0.1 part II) +0.2 part 11) +0.5 part III) +0.2 part III) +1.0 part IV) Impact resistance all NB all NB all NB Notched bar impact resistance KJ/m2 5.8 5.4 6.0 Bending resistance N/mm2 95 93 96 Youngs Modulus (from bending test) N/mm2 2600 2500 2600 Tensile strength N/mm2 59 60 59 Tear resistance N/mm2 34 37 33 Elongation at break % 120-140 40-60 100-120 Thermal non-deformability according to ISO/R75:A C 68 62 67 ISO/R75::B C 167 161 168 Flame protection according to UL 94 VO VO VO " LOI % 30-31 30-31 30-31 Tired (V) (Granulate) 1.81 1.76 1.82 Tired (V) (Injection moulding) 1.87 1.69 1.78 Table 4 (continued) Unreinforced PTMT-compositions Example 17 Example 18 Example 19 86 parts PTMT-C 86 parts PTMT-D 86 parts PTMT-D 10 parts PBB-PA 10 parts PBB-PA 10 parts PBB-PA 4 parts Sb203 4 parts Sb203 4 parts Sb203 Stabiliser: Stabiliser: Stabiliser: 0.1 part I) 0.1 part I) 0.1 part I) +0.1 part II) +0.2 part 11) +0.2 part 11) +0.7 partIV) +0.5 part II) +1.2 part IV) Impact resistance all NB 8NB:2B 6NB:4B Notched bar impact resistance: KJ/m2 5.2 4.0 3.8 Bending resistance N/mm2 92 94 98 Youngs Modulus (from bending test) N/mm2 2500 2700 2800 Tensile strength N/mm2 61 62 61 Tear resistance N/mm2 34 56 60 Elongation at break % 60-80 10-20 10-20 Thermal non-deformability according to ISO/R75: A C 59 57 58 ISO/R75:B C 163 164 162 Flame protection according to UL 94 VO VO VO " LOI % 30-31 30-31 30-31 Tired (V) (Granulate) 1.77 1.21 1.28 Tired (V) (Injection moulding) 1.69 1.23 1.26 Table 4 (continued) Unreinforced PTMT-compositions Comparative Comparative Example H Example J 86 parts PTMT-C 86 parts PTMT-C 10 parts PBB-PA 10 parts PBB-PA 4 parts Sb203 4 parts Sb203 Without Stabiliser:: stabiliser 3 parts V) Impact resistance 8NB:2B 8NB:2B Notched bar impact resistance: KJ/m2 4.1 4.0 Bending resistance N/mm2 93 95 Youngs Modulus (from bending test) N/mm2 2600 2500 Tensile strength N/mm2 58 62 Tear resistance N/mm2 32 36 Elongation at break % 10-20 10-20 Thermal non-deformability according to ISO/R75:A C 61 ISO/R75:B C 165 Flame protection according to UL 94 VO VO " LOI % 30-31 30-31 Tired (V) (Granulate) 1.65 1.68 Tired (V) (Injection moulding) 1.54 1.58 Table 4 (continued) Unreinforced PTMT-compositions Comparative Example K 86 parts PTMT-C 10 parts PBB-PA 4 parts Sb203 Comparative Stabilise Example L 4 parts VII) Pure PTMT-C Impact resistance 9NB:1B all NB Notched bar impact resistance:KJ/m2 4.2 5.5 Bending resistance N/mm2 96 86 Youngs Modulus (from bending test) N/mm2 2600 2400 Tensile strength N/mm2 61 55 Tear resistance N/mm2 35 34 Elongation at break % 10-20 182 Thermal non-deformability according to lSO/R75:A C 66 66 ISO/R75:B C - 170 Flame protection according to UL 94 VO not resistant " LOI % 30-31 #red(V) (Granulate 1.66 1.76 7red (V) (Injection moulding) 1.52 1.67 Table 5 GF-reinforced PTMT-compositions Example 20 Example 21 Example 22 58 parts PTMT-D 58 parts PTMT-D 58 parts PTMT-D 30 parts GF 30 parts GF 30 parts GF 8 parts PBB-PA 8 parts PBB-PA 8 parts PBB-PA 4 parts Sb203 4 parts Sb203 4 parts Sb203 Stabilisier: Stabilisier:Stabilisier: 0.1 part I) 0.1 part I) 0.1 part I) +0.2 part II) +0.2 part II) +0.2 part II) +0.7 part III) +1.0 part IV) +0.5 part III) Impact resistance KJ/m2 36 33 35 Notched bar impact resistance: KJ/m2 9-10 9-10 10-11 Bending resistance N/mm2 220 210 220 Tensile strength 140 135 145 Thermal non-deformability according to ISO/R75:A C 198 - 194 ISO/R75::B C > 200 - > 200 Flame protection according to UL 94 VO VO VO " LOI % 29.5-30.5 #red (V) (Granulate) 1.31 1.31 1.67 Tired (V) (Injection moulding) 1.29 1.27 1.59 Table 5 (continued) GF-reinforced PTMT-compositions Comparative Comparative Example M Example N 58 parts PTMT-D 58 parts PTMT-D 30 parts GF 30 parts GF 8 parts PBB-PA 8 parts PBB-PA Comparative 4parts Sb2O3 4 parts Sb2O3 Example O without Stabiliser: 70 parts PTMT-D stabiliser 4 parts VIJ 30 parts GF Impact resistance KJ/m2 26 28 35 Notched bar impact resistance:KJ/m2 5-7 5-7 9-10 Bending resistance N/m2 190 200 220 Tensile strength N/m2 133 136 130 Thermal non-deformability according to ISO/R75:A C 186 190 200 ISO/R75:B C > 200 > 200 > 200 Flame protection according to UL 94 VO VO not resistant LOI % 1 1 Tired (V) (Granulate) 1.18 1.20 1.21 Tired (V) (Injection moulding) 0.94 0.98 1.06 Table 6 Change of impact resistance, notched bar impact resistance and elongation at break with time on storage of injection mouldings at 1 5O0C Example 14 Example 16 Comparative Comparative Example H Example J Days Impact resistance 0 10NB 10NB 8NB/2B 8NB:2B 3 1ONB 10NB 10B 4NB:6B 5 10NB 10NB 1OB 10NB 7 1ONB 9NB:1B 10B 10NB 10 8NB::2B 9NB:1B 10B 10NB 15 5NB:5B 6NB:4B 10B 10NB Table 6 (continued) Comparative Comparative Example 14 Example 16 Example H Example J Days Notched bar impact resistance 0 5.8 6.0 4.1 4.0 3 5.4 4.7 3.1 3.5 5 5.0 5.0 2.9 2.8 7 5.1 4.8 2.0 2.3 10 3.7 3.6 15 3.6 3.4 Table 6 (continued) Comparative Comparative Example 14 Example 16 Example H Example J Days Elongation at break (%) 0 125 110 12 15 3 94 70 9 11 5 70 58 5 6 7 50 37 3 3 10 40 30 - 15 36 26 - Example 23 An unreinforced PTMT (#red=1.76dl/g) was dusted with 0.1% (I), 0.2%(II) and 0.1% (III), the percentages being based on the weight of PTMT, and extruded by co-extrusion through a single screw extruder with the temperature profile of 230 to 255 C. Then standard small rods were produced on the injection moulding machine.The standard small rods were stored under the air atmosphere at 180"0.

The variation of impact resistance and notched bar impact resistance with time in comparison with unstabilised samples is shown from the following table.

Table 7

Impact resistance (KJ/m) Notched bar impact resistance (KJ/m) Days unstabilised stabilised unstabilised stabilised 0 | without break | without break 5.1 5.5 1 | 28 | without break 4.2 | 5.4 3 without break 2.6 4.6 5 - without break 2.0 3.7 7 - without break 1.8 3.8 10 - without break - 4.2 15 - 40 - 4.0 In corresponding manner, PTMT with 30% by weight glass fibres and 0.1% by weight (I). 0.2% by weight (II) and 0.2% by weight (III), the percentages being based on the weight of PTMT, was provided and tested.

Table 8

Impact resistance (KL/m) Notched bar impact resistance (KJ/m) Days unstabilised stabilised unstabilised stabilised 0 40 47 10 13 3 31 45 9 11 5 25 46 7 11 9 9 18 43 5.5 9.5 A corresponding PTMT with Tired=1 .6 dl/g was stabilised against hydrolysis by addition of 0.1% by weight (1),0.2% by weight (II) and 1.2% by weight (IV), based on the weight of PTMT and tested for resistance to hydrolysis by heat storage of the injection mouldings at 800 C.

This test showed that the original impact resistance after the working was retained in the hot water test for about 1 2 weeks, whereas the original impact resistance with unstabilised samples was only retained for 4,weeks. In addition, the good notched bar impact resistance and elongation values were maintained in the test for 10 to 12 weeks. This points to a trouble free behaviour in use. In contrast, the unstabilised samples only maintained satisfactory notched bar impact resistance and elongation at break, which would allow their trouble-free use, for about 3 to 4 weeks.

Table9 Impact resistance Notched bar impact Elongation at break (%) (KJ/m2) resistance (KJ/m2) Weeks unstabilised stabilised unstabilised stabilised unstabilised stabilised 0 without break without break 5.2 6.0 190 225 2 without break without break 4.8 5.9 30 136 4 without break without break 4.5 5.4 13 80 6 90 without break 1.6 4.5 8 50 8 10 without break 0.9 4.8 1 34 10 - without break - 4.5 - 24 12 - without break - 4.3 - 18 14 - 28 - 1.9 - 16 16 - 12 - 1.4 - 12

Claims (35)

Claims

1. A polytetramethylene-terephthalate shaped body which is formed of polytetramethyleneterephthalate and contains triglycidyl isocyanurate and/or a bisoxazoline as stabiliser.

2. A body as claimed in Claim 1, in which the polytetramethylene terephthalate is reinforced.

3. A body as claimed in Claim 2, in which the polytetramethylene terephthalate is glass-fibre reinforced.

4. A body as claimed in Claim 2 or 3, which contains from 15 to 80% by weight of a reinforcing filler related to the polytetramethylene terephthalate.

5. A body as claimed in any one of the preceding claims, which additionally contains a phosphitic anti-oxidant and/or a phenolic antioxidant.

6. A body as claimed in Claim 5, wherein the phosphitic antioxidant is a phosphite of an at least trifunctional alcohol wherein one or two of the OH-groups of the phosphoric acid moiety are esterified with a fatty alcohol residue.

7. A body as claimed in Claim 6, wherein the alcohol is pentaerythritol and the fatty alcohol contains from 8 to 24 carbon atoms.

8. A body as claimed in Claim 7, wherein the alcohol is distearyl pentaerythritylphosphite.

9. A body as claimed in any one of Claims 5 to 8, wherein the phenolic antioxidant is 2,2' thiodiethylbis-[3-(3,5-di-tert.butyl-4-hydroxyphenyl)]-propionate or 1,3,5-trimethyl-2 ,4,6-tri-(4- hydroxy-3, 5-di-tertbutyl)benzene.

10. A body as claimed in any one of the preceding claims, which contains from 0.1 to 2.5% by weight, based on the amount of polymethyiene terephthalate, of triglycidyl isocyanurate and/or bisoxazoline.

11. A body as claimed in Claim 10, which contains from 0.1 to 1.5% by weight, based on the amount of polymethylene terephthalate, of triglycidyl isocyanurate and/or bisoxazoline.

12. A body as claimed in Claim 10 or 11 which contains from 0.02 to 0.5% by weight of 2,2' thiodiethylbis{3-(3,5-ditert.butyl-4-hydrnxyphenyl)]-prnpionate and/or from 0.05 to 0.5% by weight distearyl pentaerythritylphosphite.

13. A body as claimed in Claim 12, which contains from 0.05 to 0.3% by weight of 2,2' thiodiethylbis[3-(3,5-ditert.butyl-4-hydroxyphenyl)]-propionate and/or from 0.1 to 0.3% by weight distearyl pentaerythritylphosphite.

14. A body as claimed in any one of Claims 1 to 11 which additionally contains a co- or a graft polymer based on an acrylic acid or methacrylic ester as impact-resisting agent.

1 5. A body as claimed in any one of Claims 1 to 11, which additionally contains a co-polymer of ethylene and vinyl acetate as impact resisting agent.

1 6. A body as claimed in any one of Claims 1 to 11, which additionally contains a graft polymer of ethylene and vinyl acetate as impact resisting agent.

1 7. A body as claimed in Claim 1 5 or 1 6, in which the impact resisting agent contains from 2 to 65% by weight vinyl acetate.

1 8. A body as claimed in Claim 17, in which the impact resisting agent contains from 5 to 50% by weight vinyl acetate.

19. A body as claimed in Claim 14, wherein the impact resisting agent is a polymer of 20 to 50% by weight of an acrylic or methacrylic acid methyl or ethyl ester, together with additionally an acrylic or methacrylic acid C3 or C4 alkyl ester.

20. A body as claimed in Claim 14, wherein the impact resisting agent is a polymer of 5 to 40% by weight of an acrylic or methacrylic acid ester, 40 to 80% by weight butadiene and 5 to 35% by weight styrene, the amounts of the respective monomers to total 100%.

21. A body as claimed in any one of Claims 14 to 20, which contains the impact resisting agent in an amount of from 5 to 30% by weight of the polytetramethylene terephthalate.

22. A body as claimed in Claim 21, which contains the impact resisting agent in an amount of from 12 to 25% by weight of the polytetramethylene terephthalate.

23. A body as claimed in any one of Claims 1 to 11 and 14 to 22, which additionally contains a polymer of a bromine-containing acrylate or methacrylate as flame protecting agent.

24. A body as claimed in Claim 23, wherein the flame-protecting agent is a polymer of pentabromobenzyl acrylate.

25. A body as claimed in Claim 23 or 24, which contains from 5 to 20% by weight of the flameprotecting agent, related to the weight of polytetramethylene terephthalate.

26. A body as claimed in Claim 24 or 25, which additionally contains Sb2O3 as synergist for the flame protecting agent.

27. A body as claimed in Claim 26, which contains from 1 to 10% by weight of Sb2O3, related to the weight of polytetramethylene terephthalate.

28. A body as claimed in any one of claims 14 to 27, which contains from 0.02 to 0.3% by weight of 2,2'-thio-diethylbis[3-(3,5-ditert.butyl-4-hydroxy-phenyl)]-propionate and/or 0.05 to 0.5% by weight of distearyl pentaerythritylphosphite.

29. A body as claimed in Claim 28, which contains from 0.05 to 0.2% by weight of 2,2' thiodiethylbis[3-(3,5-ditert.butyl-4-hydroxyphenyl)]-propionate and/or 0.1 to 0.3% by weight of distearyl pentaerythritylphosphite.

30. A polytetramethylene terephthalate shaped body, substantially as described in any one of the foregoing Examples 1 to 5.

31. A polytetramethylene terephthalate shaped body, substantially as described in any one of the foregoing Examples 6 to 13.

32. A polytetramethylene terephthalate shaped body, substantially as described in any one of the foregoing Examples 13 to 22.

33. A polytetramethylene terephthalate shaped body as claimed in Claim 1, substantially as described in the foregoing Example 23.

34. A process for the production of a stabilised polytetramethylene terephthalate shaped body as claimed in any one of Claims 1 to 29, which comprises continuously supplying to an extruder polytetramethylene terephthalate, triglycidyl isocyanurate and/or a bisoxazoline and optionally one or more further components is/are chosen from a said reinforcing filler, said impact resisting agents and said polymerised bromine-containing acrylate or methacrylate flame protecting agent, which component(s) is/are supplied separately from one another and separately from the polytetramethylene terephthalate, the triglycidyl isocyanurate and/or bisoxazoline and, if used, the phosphitic or phenolic antioxidant and/or Sb2O3 being simultaneously supplied continuously and separately from one another to the extruder either together with the polytetramethylene terephthalate or one or more of said components or as materials supplied separately from any other constituent(s) of the body, and coextruding said constituents in the extruder.

35. A process for the production of a stabilised polytetramethylene terephthalate shaped body, substantially as described in any one of the foregoing Examples.