DE2706124A1 - Rapidly crystallising block copolymers - contg. block segments of low glass transition temp. e.g. polyethylene glycol!(s) - Google Patents

Abstract

Prepn. of copolyester is improved by forming a codiol-free polyethylene terephthalate resin with an intrinsic viscosity of >=0.2 dl/g, homogenising this in the melt with the codiol and the block segment polymer, and subjecting the solidified melt to solid phase post-condensation. The prods. are moulding materials with exceptionally good crystallisation properties. They can be injection moulded at mould temps. of 80-120 degrees C, esp. 90 degrees C whilst retaining their rapid crystallisation characteristics, so that moulds can e.g. by water cooled. The prods. can be moulded using considerably shorter cycle times than with conventional polyethyleneterephthalate injection moulding materials.

Description

Fast crystallizing block copolyesters

Addendum to patent (patent application P 25 45 720.9) The German patent application P 25 45 720.9 relates to highly crystalline, rapidly crystallizing thermoplastics Block copolyester with an intrinsic viscosity of at least 0.4 dl / g from A. 60 - 95 wt .-%, based on the sum of A and B, copolyester segments based on Terephthalic acid, ethylene glycol and codiol residues and B. 40-5% by weight, based on to the sum of A and B, block segments linked to A with a glass transition temperature below 0 ° C and an average molecular weight of 400 to 1,000,000, where A and B are linked to one another via carboxylate groups, characterized in that A from a) at least 90 mol%, based on the acid component, terephthalic acid residues, b) 90 - 99.5 mol%, based on the sum b) + c), ethylene glycol residues and c) 10 - 0.5 mol%, based on the sum b) + c), residues of codiolus lit 4 - 10 carbon atoms, the OH groups of which are branched by aliphatic. or unbranched alkylene groups with 3 or 4 carbon atoms are separated and either 1. carry at least one secondary or tertiary OH group or 2. two primary ones Carry OH groups and are unsubstituted, mono- or dialkyl-substituted, with ii In the case of substitution, the sum of the carbon atoms of the substituents is at least 4 is.

These copolyesters can be produced in a manner known per se, by lan the dicarboxylic acids, preferably pure terephthalic acid, and / or the corresponding Dimethyl ester 1.05 to 4.0, preferably 1.8-3.6 mol of the diols, based on 1 mole of dicarboxylic acid component, and with the addition of the polymer as a block segment is to be incorporated chemically, in the presence of Yeresternngs- and / or transesterification catalysts between 150 and 250 ° C esterified or transesterified (reaction step I) and the thus obtained Reaction products under normal conditions, i.e. in the presence of esterification catalysts polycondensed between 200 and 300 ° C under reduced pressure (<1 Torr) (reaction step IT).

A particularly preferred embodiment is that the codiols together with the block segment polymers of the reaction mixture as late as possible, that is only after the reaction of terephthalic acid or its ester-forming derivatives has taken place with ethylene glycol too. Bis (2-hydroxyethyl) terephthalate, or even more advantageous only after formation of a polyethylene terephthalate prepolymer with a degree of polycondensation of more than 4 are added. After that, the mixture can then be used in the usual way, such as described above, are polycondensed.

It has now surprisingly been found that a particularly good Crystallization behavior of the end product can be achieved by first a Codiol-free polyethylene terephthalate with an intrinsic viscosity of at least 0.2 dl / g (measured as a 0.5% strength by weight solution in a phenol / tetrachloroethane mixture Weighting ratio 1: t7 at 250C), this with the codiol and the block segment polymers homogenized in the melt and the solidified melt then undergoes solid phase post-condensation subject.

The present invention therefore relates to a method of production highly crystalline, rapidly crystallizing, thermoplastic block copolyester with an intrinsic viscosity of at least 0.4 dl / g from A. 60-96% by weight, based on on the sum of A and B, copolyester segments based on terephthalic acid, Ethylene glycol and codiol residues and B. 40 - 5 wt .-%, based on the sum of A and B, block segments linked to A with a glass transition temperature below OOC and an average molecular weight of 400 to 1,000,000, with A and B above Carboxylate groups are linked to one another and A is based on a) at least 90 mol% on the acid component, terephthalic acid residues, b> 90 - 99.5 mol%, based on the sum b) + c), ethylene glycol residues and c) 10 - 0.5 mol%, based on the sum b) + c), residues of codiols with 4 - 10 carbon atoms, the OH groups through aliphatic branched or unbranched radicals with 3 or 4 carbon atoms are separated and which either 1. carry or at least one secondary or tertiary OH group 2. carry two primary OH groups and are unsubstituted, mono- or dialkyl-substituted are, in the case of substitution, the sum of the carbon atoms of the substituents is at least 4, according to which one per mole of terephthalic acid and / or terephthalic acid dimethyl ester, up to 10 mol%, based on the dicarboxylic acid component, by other aromatic, replaced cycloaliphatic or aliphatic dicarboxylic acids or their dimethyl esters can be 1.05 to 4.0 mol of diols, which consist of ethylene glycol and codiol c), together with the block segment polymer B with a glass transition temperature below OOC and an average molecular weight of 400 to 1,000,000 are known per se Way in the presence of esterification and / or transesterification catalysts between 150 and 2500C esterified or transesterified and the reaction products thus obtained in the presence polycondensed by esterification catalysts between 200 and 3000C at reduced pressure according to patent (patent application P 25 45 720.9), characterized in that one first a Codiol-free polyethylene terephthalate with an intrinsic viscosity of at least 0.2 dl / g produces this with the codiol and the block segment polymer in the melt homogenized and the solidified melt then subjected to solid phase post-condensation.

The invention furthermore relates to this process available copolyesters.

The intrinsic viscosity is in each case as a 0.5% strength by weight solution in a phenol / tetrachloroethane mixture (weight ratio 1: 1) measured at 250C.

The glass transition temperature is determined with the help of differential thermal analysis determined (DSC2, Perkin Elmer).

Terephthalic acid copolyester residues are also suitable as block segments A an average molecular weight of 5,000 - 50,000 (according to the light scattering method in trifluoroacetic acid).

The following polymer segments or mixtures come as block segments B the same in question: 1. Linear and / or branched polyolefins from olefins with 2 - 5 carbon atoms and an average molecular weight of around 400 to 106 (values up to 10,000 vapor pressure osmometric, above 10,000 up to 200,000 membrane osmometric, above 200,000 determined by the light scattering method) such as polyisobutylenes, polyisoprenes, Polybutadienes, polypropylenes, preferably polyethylenes, with functional hydroxyl or Carboxyl groups that can be obtained by targeted thermo-oxidative degradation.

2. Polyalkylene glycols (more precisely: poly (alkylene oxide) -w.w'-diols) with an average molecular weight of about 400 to 100,000, preferably of 2,000 up to 25,000 (values up to 20,000 determined by OH end group determination; values up to 100,000 membrane osmometrically determined) and a carbon / oxygen ratio from about 2.0 to 4.5, such as polyethylene glycols, polypropylene glycols, polybutylene glycols.

The codiols c) ko-enes are preferably diols with at least one secondary or tertiary OH group in question, such as 2-ethylhexanediol-1,3; 3-methylpentanediol-2,4t 2-methylpentanediol-2,4; 2,2,4-trimethylpentanediol-1,3; Hexanediol-2,5; 1,3-butanediol; but also diols with two primary OH groups, such as 2,2-diethylpropanediol, Üutanediol-I, 4, 1,3-propanediol are suitable.

The positive effect the remains of the codiols listed decreases to the rate of crystallization of the block copolyester according to the invention in the order listed.

The polycondensates according to the invention crystallize considerably faster as pure polyethylene terephthalate and have a very high melting point - So a combination of properties that have been very desirable and made by so far known terephthalic acid ester has not been achieved.

You can at mold temperatures between 120 and 80 ° C, preferably at about 900 C, and allow a substantial amount under these conditions shorter cycle times than conventional polyethylene terephthalates containing nucleating agents. The rate of crystallization can still be reduced by adding nucleating agents further increase.

In addition, the block copolymers according to the invention have opposite a conventional blend of polyethylene terephthalate and a second polymer (DT-OS 21 09 560, 22 55 654, 23 10 034, 23 30 022, 23 64 318) the decisive one Advantage that they have against oxidative and hydrolytic influences due to their higher crystallization rate and crystallinity are significantly more stable.

But this also means that therio-oxidatively unstable polymers such as Polyalkylene glycols, especially polypropylene glycols and polyethylene glycols, as Block segments B can be used without being involved in injection molding processing with a melt temperature of 2600 C a stronger degradation occurs than with pure Polyethylene terephthalate. A copolymer of pure polyethylene terephthalate and a Polyalkylene glycol (CB-PS 682 866, US-PS 2,744,087) can under the above conditions likewise cannot be processed without decomposition.

There is a drastic decrease in molecular weight. The one from it moldings obtained are brittle and brittle.

The dicarboxylic acid component of the polyalkylene terephthalate A) consists from terephthalic acid, which is up to 10 mol%, based on the acid component other aromatic dicarboxylic acids with 6-14 carbon atoms, through aliphatic dicarboxylic acids with 4 - 8 carbon atoms or by cycloaliphatic dicarboxylic acids with 8 - 12 carbon atoms can be replaced. Examples of such dicarboxylic acids are phthalic acid, Isophthalic acid, naphthalene-2,6-dicarboxylic acid, diphenyl-4,4'-dicarboxylic acid, adipic acid, Called sebacic acid and cyclohexanediacetic acid.

Of course, the polyalkylene terephthalates A) by three- or tetravalent alcohols or tri- or tetrabasic acids are branched, as described, for example, in DT-OS 1 900 270 (# US-PS 3,692,744). Suitable Branching agents are, for example, trimesic acid, pyromellitic acid, trimethylolpropane and ethane, pentaerythritol. It is recommended not to exceed 1 mol% based on the acid component to use branching agents.

For the esterification reaction and for the polycondensation reaction can apply all known catalysts used z. E.g .: mono- and / or polymeric Tetraalkyl titanates with alkyl radicals having 1 to 10 carbon atoms, e.g. B. tetrabutyl titanate, Tetraisopropyl titanate, acetates of mono- and divalent metals such as zinc, manganese, Calcium, cobalt, lead, cadmium, sodium, lithium, compounds of the trivalent Antimony, such as antinantrioxide, antimony triacetate, antfrontrichiorid, compounds, derived from antimony and glycols, Compounds of the trivalent Boron such as boric acid, boric anhydride, borates, compounds that differ from boron and Derive glycols, compounds of tetravalent germanium, such as amorphous germanium dioxide, Gerianium tetrachloride, compounds derived from germanium and glycols or mixtures of the catalysts mentioned.

Those preferred for making the copolyesters according to the invention Catalysts are the acetates of zinc, manganese, cadmium and calcium, the compounds of germanium, such as cermanium dioxide, especially as a glycolic solution, of boron such as boric anhydride or borates, of antimony such as antimony trioxide, especially as glycolic solution and titanium such as tetraalkyl titanates, e.g. B. tetraisopropyl titanate, or Combinations of the compounds mentioned.

To protect against thermo-oxidative degradation, the invention Copolyesters the usual amounts, preferably 0.001 to 0.5% by weight, based on the copolyester, known stabilizers are added. Suitable as such phenols and phenol derivatives, preferably sterically hindered phenols, amines, preferably secondary arylamines and their derivatives, quinones, phosphites and phosphates, preferably aryl derivatives, copper salts of organic acids and addition compounds of Cu (I) halides to phosphites.

The process according to the invention can be carried out batchwise in corresponding Reaction and mixing apparatus are carried out.

A particularly preferred form is the continuous mode of operation on screw machines, with homopolyethylene terephthalate, block segment polymer and Codiol are metered in together or block segment polymer and Codiol in the homopolyethylene terephthalate melt are added. That way manufactured Compared to the patent (patent application P 25 45 720.9), block copolyesters have Block copolyesters produced in the manner described have the additional advantage that they crystallize even faster.

The start of crystallization is usually 10 - 200C above that Start of crystallization of the comparable block copolyester and 40 to about 60 ° C. above that of polyethylene terephthalate.

The high crystallinity of the block copolyester, the hardness, dimensional stability and dimensional stability is guaranteed even at higher temperatures, is achieved more quickly, and thus a considerable reduction in the mold life of the injection cycle.

To achieve a high molecular weight, the invention Copolyester subjected to solid post-condensation. Usually this will be granulated product in a rotating apparatus in vacuo at a pressure below 1 Torr or in a stream of nitrogen and a temperature which is 60 -C C below the polymer melting point is post-condensed.

The copolyesters according to the invention can of course be reinforced with reinforcing materials be reinforced. Metals, silicates, carbon, Glass, primarily in the form of fibers, fabrics or mats, has proven its worth. Preferred reinforcement material are glass fibers.

In addition, natural, if desired, inorganic or organic Pigments, dyes, lubricants and release agents such as zinc stearate, UT absorbers, etc. in usual amounts can be added.

In order to obtain flame-retardant products, 2 to 20 wt .-% is required on the molding compound, known flame retardants such as B. halogenated Compounds, elemental phosphorus or phosphorus compounds, phosphorus-nitrogen compounds, Antimony trioxide or mixtures of these substances, preferably antimony trioxide, Decabromodiphenyl ether and tetrabromobisphenol A polycarbonate were added.

The rate of crystallization of the copolyesters according to the invention can by adding 0.01 to 1 wt .-%, based on the unfilled and unreinforced Copolyester, nucleating agent, can be increased. The dem are suitable as such Compounds known to those skilled in the art, as z. B. in Kunststoff-Handbuch, Volume VIII, nPolyesters, Carl Hanser Verlag, Munich 1973, p. 701, are described.

The copolyesters of the present invention are excellent starting materials for the production of foils and fibers, preferably for the production of Moldings of all kinds by injection molding.

They allow the mold temperatures to be maintained the good crystallization behavior can be reduced below 1000C and thus water-heated Shapes can be used.

Examples The samples were characterized by their intrinsic viscosity and the important thermodynamic data for melting and crystallization behavior such as melting enthalpy (A Hm), melting temperature (Tm), and crystallization temperature (Tc) characterized.

The earlier at a constant cooling rate and under otherwise identical test conditions The higher the rate of crystallization, the higher the polymer crystallizes out i.e.

the subcooling aT = Tm - Tc indicates when the crystallization rate reached its maximum under the cooling conditions used.

The parts mentioned in the following examples are parts by weight: Examples 1-4 90 parts of polyethylene terephthalate granules with a manganese (II) acetate content of 0.04% by weight, a germanium dioxide content of 0.01% by weight and an intrinsic viscosity of 0.672 dl / g (measured in a phenol / tetrachloroethane mixture in the weight ratio 1: 1 at 25 ° C) together with 10 parts of block segment polymer and 0.5 part of 2-ethylhexanediol-1,3 intimately mixed in a mixer and then melted in a twin-screw extruder and homogenized in the melt at 260C. The polyester melt is through a Spun off water bath, granulated and the granules in a tumble dryer at 2250C polycondensed in a stream of nitrogen.

COMPARATIVE EXAMPLES 5-8 5826 g (30 mol) of dimethyl terephthalate become with 4104 g (66 mol) of ethylene glycol in the presence of 4.62 g of calcium acetate with stirring and bubbling with nitrogen heated for 2 hours at 2000C in a 25 l autoclave, wherein Methanol is distilled off. After the transesterification has ended, 36 ml of GeO2 solution are added (5% by weight in ethylene glycol), 6 g of trisnonylphenyl phosphite, 26.3 g (0.18 mol) of 2-ethylhexanediol-1,3 and 600 g (10% by weight) of block segment polymer. The temperature is raised to 2100C and held for 2 hours. Then the temperature is increased within another Hour to 2500C and evacuated the apparatus (1.0 Torr) at the same time. Finally The mixture is stirred for a further 2 hours at 250 ° C. and a pressure of less than 0.5 torr.

The polyester melt is then spun through a water bath and granulated.

Examples 1-4 (Table 1) describe the according to the invention Process produced block copolyester. The amount for hypothermia is at these products are approx. 10 ° C lower than those according to the patent (patent application P. 25 45 720.9) produced block copolyesters (Examples 5-8), d. H. the after Block copolyesters produced by the process according to the invention crystallize considerably faster than the polyesters obtained by the conventional polycondensation method. The corresponding data for pure polybutylene terephthalate and polyethylene terephthalate show example 9 and 10.

Table 1 polyethylene glycol terephthalate block copolyester with 0.6 mol% 2-ethylhexanediol-1,3 as codiol and 10% by weight polyethylene glycol or polyethylene as block polymer, for example block segment polymer 1 Polyethylene glycol (Mn = 4000) 0.78 9.0 244 200 44 2 Polyethylene glycol (Mn = 6000) 0.86 9.2 248 205 43 3 Polyethylene glycol (Mn = 20,000) 0.85 9.6 254 214 40 4 Polyethylene (Mw = 96000), 0.83 8.5 251 192 59 containing carboxyl groups 1.3% by weight COOH 5 polyethylene glycol (Mn = 4000) 0.76 8.8 241 183 58 6 polyethylene glycol (Mn = 6000) 0, 87 8.9 242.5 185.5 57 7 polyethylene glycol (Mn = 20,000) 0.81 9.6 256.5 205.5 51 8 polyethylene (Mw = 96000), 0.84 8.2 250 184 66 carboxyl groups containing 1.3% by weight COOH 9 homo-polybutylene terephthalate 0.87 9.2 226 173 53 10 homo-polybutylene terephthalate 0.72 7.8 255 152 103 In the table: #: Intrinsic viscosity in phenol / tetrachloroethane 1: 1 measured in a capillary viscometer according to Ubbelohde, polymer concentration: 0.5 g / dl, temperature 25 ° C #Hm: melting enthalpy Tm: melting temperature Tc: crystallization temperature, measured with DSC 2 (Perkin Elmer) with a weight of approx. 10 mg and heating - and cooling rate of 20 ° C / min.

Claims (2)

Claims 1. A method for producing highly crystalline, fast crystallizing, thermoplastic block copolyester with an intrinsic viscosity of at least 0.4 dl / g from A. 60 - 95% by weight, based on the sum of A and B, Copolyester segments based on terephthalic acid, ethylene glycol and codiol residues and B. 40-5% by weight, based on the sum of A and B, of block segments linked to A. with a glass transition temperature below OOC and an average molecular weight from 400 to 1,000,000, where A and B are linked to one another via carboxylate groups and A from a) at least 90 mol%, based on the acid component, terephthalic acid residues, b) 90 - 99.5 mol%, based on the sum b) + c), ethylene glycol residues and c) 10 - 0.5 mol%, based on the sum b) + c), residues of codiols with 4 - 10 carbon atoms consists, whose OH groups by aliphatic, branched or unbranched radicals with 3 or 4 carbon atoms are separated and either 1. at least one secondary or carry tertiary OH groups or 2. carry two primary OH groups and are unsubstituted, are mono- or dialkyl-substituted, the sum in the case of substitution of the carbon atoms of the substituents is at least 4, after which one per mole of terephthalic acid and / or dimethyl terephthalate, which is up to 10 mol%, based on the dicarboxylic acid component, by other aromatic, cycloaliphatic or aliphatic dicarboxylic acids or Their dimethyl esters can be replaced by 1.05 to 4.0 moles of diols derived from ethylene glycol and Codiol c exist, together with the block segment polymer B with a glass transition temperature below 0 ° C and an average molecular weight of 400 to 1,000,000 per se known manner in the presence of esterification and / or transesterification catalysts between 150 and 250 ° C esterified or transesterified and so the reaction products obtained in the presence of esterification catalysts between 200 and 3000C at reduced Pressure polycondensed according to patent (patent application P 25 45 720.9), characterized in that that you first get a Codiol-free polyethylene terephthalate with an intrinsic viscosity of at least 0.2 dl / g, this with the codiol and the block segment polymer homogenized in the melt and the solidified melt then undergoes solid phase post-condensation subject. 2. According to the method of claim 1 obtainable block copolyesters.