CS207463B2 - Method of making the thermoplastic elastomere - Google Patents

Description

The invention relates to a process for the production of thermoplastic elastomers consisting of alternately arranged copolyesteramides.

Numerous co-polymers are known to be obtained by polycondensation of a diester with a low molecular weight glycol and a polyglycol, generally polyoxyialkylene glycol having a molecular weight of 1000 to 3000. These materials have a very special morphology because they consist of hard crystalline zones (hard segments) immersed in amorphous regions having an elaistomeric nature (soft segments). Such " hard-soft " structures cause these to be classified as elastoplastic materials, i.e., materials that can be converted into finished products having elastic properties that are superior to those of conventional plastic materials. C-NH-R "'wherein R' is an alkyl radical of 1 to 8. carbon atoms and / or aryl radicals of up to 10 carbon atoms and / or cycloalkyl radicals of 4 to 10 carbon atoms and R "and R" 'are divalent hydrocarbon radicals of 2 to 30 carbon atoms, the materials of which, by means of fast and cheap processing procedures. Typical processing techniques for this group of polymers are: injection molding, extrusion, compression molding, rotomolding, blow molding and the like.

SUMMARY OF THE INVENTION The present invention provides a process for the manufacture of a thermoplastic elastomer based on a regularly ordered copolyesteramide consisting of 2 to 80% by weight of segments derived from 1,6-hexanediol, 93 to 20% by weight segments derived from polyoxyalkylene glycols. the segments are linked to each other by ester linkages via a diesterdiamide-derived residue containing preformed amide bonds having the general formula

OO-NH-C-R-C-OR 'consists in heating a mixture of the above diesteramide and polyoxyalkylene glycol with an excess of 1,6-hexanediol at a temperature between 220 ° C to 240 ° C and thus obtained the mixture is distilled between 250 ° C and 270 ° C.

For example, these two types of macromolecular components can be represented by the following formulas:

).)

O-PAG-O-C-R-C'11 II O O

(h)

Wherein the PAG is a divalent radical derived from polyoxyalkylene glycols having a molecular weight in the range of 400 to 3500, A is a divalent radical derived from 1,6-hexanediol having a molecular weight of less than 250, R is the divalent radical of diesteramide of the above of the formula, R 'and R' 'are selected from divalent hydrocarbon radicals having 2 to 30 carbon atoms, such as:

(a) alkylene radicals of the type:

- (CH ₂ J _m -, - (CH ₂ J _{m -} C - (iOH ₂ J _m -,

CH ₂ —CH ₃ CH ₃ CH ₃ CH ₃ CH ₃ - (CH ₂ ) _m —CH — CH (CH ₂ ) _m -, wherein m is an integer between 2 and 20;

b) arylene radicals such as para-phenylene or meta-phenylene, para-xylylene or meta-xylylene;

c) alicyclic residues such as 1,4-cyclohexylene, 1,3-cyclohexylene, 2-methyl-1,4-cyclohexylene, 2-methyl-1,3-cyclohexylene, dicycloarylmethylene and others.

The above diesteramides are produced by the following general reaction

R'O-C-R-C-CR 3 + H N-R-NH->

II π A Λ.

o o

- * R'O-C-RC-NH-R-NH-C-RII O II

OO o

-C-OR '+ 2 RCH2O as claimed in Italian Patent Specifications Nos. 908,843 and 908,844 to the same applicant. The substituents R ‘, R,, R‘ ‘are as previously defined.

The use of diesteramides in thermoplasmic elalstomers makes it possible to obtain highly crystalline hard phases having a high melting point and a high crystallization rate. In addition, the melting point is less sensitive to changes in the large variation in the enthalpy of melting, which are characteristic of polymers having crystalline phases with hydrogen bonds.

It is desirable that the macromolecular components of type b], formerly called "hard segments", be present in the polymer in a percentage of between 20 and 80% by weight. They are formed by repeating units with a molecular weight of about 500 and are obtained by reacting diesteramide with a low molecular weight dlol (molecular weight less than 250).

Macromolecular components of type a) are obtained by reacting dielsteramide with polyoxyalkylene glycols having a molecular weight ranging from 400 to 3500. Characteristic examples of such polyoxyalkylene glycols are (1,2-proipyleneoxy) glycol poles, (1,3-propyleneoxy) glycol poles, poles (fetramethylenenoxy) glycol, dihydroxyl-terminated copolymers of either random or block type ethylene oxide and 1,2-propylene, and copolyglycols of tetrahydrofuran and methyltetrahydrofuran.

Products having good technological properties are also obtained by simultaneously reacting polyoxyalkylene glycol with two different types of diesterdiamides and low molecular weight glycols.

The copolyye amide which is most preferred for the purposes of the present invention is copolyesteramide obtained from N, N‘-dicarbomethoxybenzoylhexane methylenediamines (6NTJ, 1,6-hexanediol and polytetramethylene ether glycol of molecular weight in the range of 600 to 2000).

Polymers as described herein are prepared by a transesterification and polycondensation process. This process is carried out by heating the mixture of dlesterdia, mid and polyoxyalkylene glycol with an excess of 1,6-hexanediol in the presence of a catalyst at a temperature of from 220 ° C to 240 ° C. In this state, the methanol formed during the tirahsesterification is distilled. The reaction is carried out under an inert atmosphere with vigorous stirring and continued until a theoretical amount of methanol is obtained. This time is a function of temperature, the type of catalyst used and the excess glycol used.

This stage of the process results in a low molecular weight prepolymer which is converted to a polymer of the appropriate molecular weight by distillation at high temperatures (250 to 270 ° C) with stirring and under a vacuum of less than 1.33 mm ² , excess of low molecular weight glycol and glycol formed during polycondensation, wherein the distillation is accompanied by redistribution of copolyestaric units up to 207463, which redistribution creates a statistical distribution of these units in the macromolecular region.

The duration of polycondensation, as a function of the operating conditions to be used, is usually between 1 and 4 hours.

Although catalysts of different types may be used, titanium alcoholates and in particular titanium tetraisopropylate which has been added diluted in isopropanol for better metering have proven to be particularly advantageous.

Both steps of this process, transeistarification and condensation, are usually carried out without solvents, the materials being in the molten state.

The stability of the copolymers of the invention, in particular in some types, is conditioned by the presence of heat and UV stabilizers.

The mechanical properties of these copolyesteramides can be altered by the addition of some inorganic additives such as carbon black, silica gel, alumina, glass fibers, thereby improving the modulus of elasticity of the material.

The copolyesteramides of the present invention, since they contain pre-formed amide groups in their molecule, which form hydrogen bonds, have mechanical properties that are superior to those of conventional similar thermoelastomeric materials that are exclusively polyester based, because the presence of this The type of inter-chain bond actually promotes separation between the crystalline and amorphous phases, the existence of which, as mentioned above, is a special property of these elasitomers.

In the following examples, percentages are by weight, the intrinsic viscosity (IV) is expressed in deciliters per gram (dl / gj) and measured in a 50:50 phenol / carbon tetrachloride solution at 25 ° C at a concentration of 0, 6 ° / o.

The melting point was determined by differential thermal analysis using a temperature corresponding to the minimum endothermic curve obtained at a heating rate of 10 ° C per minute.

The following methods were used to determine the technological properties of the polymer samples given in some examples: ultimate deformation load tensile strength of permanent deformation at

100% extension

DIN-53504/53

The Clash-Berg module ASTM D 478 / DIN III torsional permanent crushing

Izod impact test

Sbore hardness D swelling in oil, ASTM Type 3 swelling in fuel B swelling in fuel C

ASTM D 395 / Meth. ASTM D 256/56

ASTM D 2240

ASTM D 471.

The following changes have been introduced to the above tests:

1. When crushing is determined, the specimen recovery after deformation is performed at test temperature and not at room temperature.

2. Swelling tests were performed on samples measuring 1 x 4 x 12 mm.

3. Tensile tests were performed at a stretching speed of 50 mm per minute.

The samples were prepared by pressing: at temperatures in the range of 20 to 30 ° C above the melting point of the particular polymer. They were previously dried at 100 ° C for 5 hours under vacuum.

Examples 1 to 3

A 500 ml three-necked flask equipped with a stirrer, an inert gas inlet tube and a methanol / hexanediol distillation adapter is charged with 100 g of N, N‘-dicarbetaxybenzoylhexamethylenediamine (6NT),

56.8 g of 1,6-h.exandiolu, 0.05 millimole of titanium tetraisopropylate various amounts of polyoxyethylene glycol (average molecular weight 1500), so as to give an initial reaction mixture of 5 mole%, 10 mole ° / o and about 15 mol / _o (based on 6NT monomer) of polyoxyethylene glycol. The flask was repeatedly evacuated and always filled with nitrogen. It was then placed on a bath of fluidized sand, which was preheated to 240 ° C and then, once the mass began to melt, stirring was started. The reaction begins immediately with the release of methanol and is carried out under an inert atmosphere. · After 40 minutes the transesterification is completed in reality, and polycondensation takes place, which takes place at 270 ^Q C and a pressure of 0,67.10 ² kPa.

Once the polymer of the desired viscosity is obtained, the flask is brought to ambient pressure with an inert gas and rapidly transferred to a water cooling bath. After cooling, the polymer has the appearance of a white mass which is then crushed in a rotating paddle! mill.

Technological and physico-chemical properties of some samples): are given in Table 1.

TABLE 1

Example 1 mole% (PEG) 5 polycondensation time (min.) 70 relative viscosity (1 ° / o, 25 ° C) 2.81 melting point ° C (DSC) 259 permanent load 30 deformation (MPa) tensile strength (MPa) 42 ductility (° / o) 400 permanent deformation by pressure, 31.2 at 25 ° C (%) permanent deformation by pressure 5.5

at 100 ° C (%)

15 Dec

110

3.01 3.03

253 250

28.5 21,5

29

530 600

35.1

49.5 56.9

Example 4

100 g of 6NT s were reacted in the same manner as in the previous examples

56.8 g of 1,6-hexanediol and 45.4 g of polyoxyethylene glycol having an average molecular weight of 1000. 0.05 millimoles of titanium tetraisopropylate and 187 mg of N, N-bis (β-naphthyl) p-phenyldiamine as heat stabilizer were added.

After 135 minutes of reaction to obtain a polymer having an intrinsic viscosity (iv) of 1.35 and a melting temperature of 248 ^q C. It had the following technological properties:

Shere D hardness 59 permanent load deformation (MPa) 26 tensile strength (MPa) 31. elongation (%) 300 permanent deformation by pressure at 25 ° C (%) 36

permanent strain at 100 (1%) 58.

Examples 5 and 6

In the same manner as in Examples 1 to 3, 100 g of 6NT was reacted with 36 g of 1,6-hexanediol and varying amounts of 2000 average molecular weight polytetramethylene ether glycol. 0.05 millimoles of titanium tetraisopropylate titanium catalyst was added along with 184 mg of 4,4 ' bis (α, α-dimethylbenzyl) diphenylamine as a heat stabilizer for the polymer.

The physicochemical properties and technological specifications are given in Table 2, which also shows the composition of the polymer in% by weight of macromolecular segments containing hardened (FHj low molecular weight diol).

TABLE 2

Example polycondensation time (min.) Intrinsic viscosity (dl / gj melting point (° C) hard phase (%) ultimate strain (MPa) tensile strength (MPa) ductility (%)

In the apparatus described in the previous examples and by the same procedure, copolyesteramides having different compositions were prepared by reacting 6NT and 1,6-hexanediol (6NT to 1,6-hexanediol molar ratio of 1: 2.1) with different amounts of polyoxytetramethylene glycol having an average molecular weight 1000.

6

95

1.19 1.48

260 255

61.8 38.5

27,6 15,0

45

400 700

Titanium tetraisopropylate in an amount of 0.022 moles O / _O relative to BNT was used as catalyst and 4,4'-bis ('α ^, α-dimethylbenzyl) diphenylamine corresponding to 0.14%, calculated on final polymer.

Table 3 shows the technological and physico-chemical properties of the samples.

10

TABLE 3

Example 7 8 9 10 polycondensation time (min.) 63 75 81 85 intrinsic viscosity (dl / g) 1.30 1.48 1.55 1.70 melting point (° C) 256 251 246 238 hard phase (% J (found) 77 64.7 51.2 35.8 Shore hardness (D) 76 70 65 56 permanent load 47.8 31.6 23.5 18 deformation (MPa) tensile strength (MPa) 38.4 34 38.8 45.4 elongation (%) 53 750 530> 660 tensile strain at 12.5 7 5 4 : 25% elongation (%) tensile strain at - 71 57 46 100% Elongation (%) compression strain at 25 ° C 46 34 35 35 (%) compression strain at 100 ° C 55 50 50 50 ('%) change in AV volume (%) in oil 3 6 8 12 at 100 ° C after 7 days AV volume change (° / o) 4 10 12 17 in fuel B after 70 hours at room temperature AV volume change (%) 4 12 14 19 Dec in fuel C after 70 hours at room temperature short circuit module at 25 ° C (MPa) 578 195 87 63 Izod's character. Ex. at 25 ° C —- - none breakage * none breakage Izod's character. Ex. at -40 ° C - " none breakage none breakage

Example 1 a d 11

Technological evaluation of the copolyye ether amide samples was carried out on the pressed samples, which were cooled with flowing water while still under pressure.

As is known, the properties of the seimicrystalline materials are a function of the amount of crystalline phase. The level of crystallinity of the sample is a function of the cooling rate and crystallization rate at various temperatures.

In order to show the high crystallization rate of the copolymers of the present invention, which high speed is the reason for using standard molding procedures for these polymers, the crystallinity of the molded samples was measured and after cooling at temperatures below 40 ° C below the melting point (temperature). maximum crystallization rates) over time intervals between 10 and 30 minutes. The percent crystallinity was evaluated by different calorimetric measurements.

Table 4 shows the results.

TABLE 4

Example 7

intrinsic viscosity (dl / g) 1. hard phase (%) 77 melting point (° C) 256 crystallinity ('%) 40 % crystallized 50 hard segments

8 9 10 1.48 1.55 1.70 64.7 51.2 35.8 251 246 238 37 33 24 55 59 59

The percentage of crystallinity was not substantially affected by the type of cooling. As can be seen from Table 4, a large percentage of crystalline hard phase can be obtained with these copolymers by simple processes without any particular cooling or cooling procedures.

Example 12

As is known for elastic-plastic materials, the two key elements for their formation are the uniformity of the modulus of elasticity at different temperatures and the width of the thermal in207463 terval in which the modulus has values that are of interest for practical applications.

For copolyesteramides of different compositions, the elastic moduli at different temperatures were evaluated and compared to those of the copolyester (i.e., without hydrocarbon bonds), which has an analogous composition to the hard and soft segments.

The module values shown in Table 5 were measured by a Rheovibron dynamic viscoelastometer on annular samples, using appropriately modified clamps and without making any sample length changes.

The data show that the change in modulus of elasticity as a function of temperature is less for copolymers containing amino groups that have the ability to form hydrogen bonds.

TABLE 5

Sample

Control A 2

Control B hard phase (%) modulus of elasticity at

800 ° C (MPa) modulus of elasticity at 360 ° C

100 ° C (MPa) modulus of elasticity at 250

150 ° C (MPa) modulus of elasticity at 180

200 ° C (MPa)

Example 13 (A-B-C)

A 500 ml three-necked flask equipped with a stirrer, inert gas inlet tube and a methanol / hexanediol distillation adapter is charged with 100 g of 6NT monomer,

56.8 g hexanediol, 0.05 millimoles titanium tetraisopropylate, 45.4 g polyoxyethylene glycol (PEG) having an average molecular weight of 1000 (20 mol% relative to 6NT) and 1135 mig of Naugard 445, which is 4.4'-bls ( (α, β-dimethylbenzyl) diphenylamine.

The flask is evacuated repeatedly and filled with nitrogen each time. The flask was then placed in a bath of fluidized sand that had been superheated to 240 ° C and stirring was started as soon as the mass melted. The reaction begins

80.5 51.2 61.4

500 360 750

140 220 260 85 160 160 indefinable 100 ALIGN! 70

immediately with the evolution of methanol and proceeds at ambient pressure in an inert gas atmosphere.

After 40 minutes, the trans-transesterification is complete and p-glycondensation begins, which takes place at a temperature of 270 ° C and a residual pressure of about 0.67.10 ² Pa. Once the polymer mass of the desired viscosity is obtained, the flask is brought to ambient pressure by introducing an inert gas and quickly transferred to a water cooling bath.

The polymer obtained after cooling is a white mass which is crushed in a rotary paddle mill. Using the same procedure and varying the amount of reagents, a series of copolymers having different compositions, the technological and physicochemical properties of these compounds are prepared in Table 6.

TABLE 6

Example AND (B) C mole% (PEG) 20 May 30 50 polycondensation time (min.) 210 295 275 intrinsic viscosity at 25 ° C 1.36 1,25 1,21 (dl / g) melting temperature (° C) 242 227 207 - Hard segments (weight) 58.9 45.5 26.4 percent) permanent load 24.4 18.8 11.0 deformation (MPa) tensile strength (MPa) 42.6 35.6 22.9 elongation (%) 445 550 525 Shore D hardness 66 59 50 tensile strain at ^{25 0} / o 10 8 8 elongation (%) tensile deformation at 100% 60 52 44

extension

Example 14 (D-E-F)

By the same procedure as in the previous examples, different amounts of 6NT polyhydroxyethylene glycol with an average molecular weight of 1500, hexanediol (ED) (average reacted, and copolymers of different compositions and properties were obtained as shown in Table 7. In all tests, Naugard 445 was used as an antioxidant in an amount corresponding to 2.5% by weight relative to polyhydroxyethylene glycol;

hexandiol measures to 6NT were 2.1) are left in the reaction. TABLE 7 Example D E F mole% PEG 21.7 32.6 43.4 polycondensation time (min.) 195 300 290 intrinsic viscosity at 25 ° C 1.43 1.39 1.32 fdl / g) melting point (° C) / 243 .219 210 hard segments (weight%) 50.4 36.7 26.9 permanent load 18.7 11.3 8.3 deformation (MPa) tensile strength (MPa) 3-2,3 27.4 23.4 elongation (%) 525 635 735 tensile strain at 23% 9 8 7 elongation (%) tensile deformation at 100% 51 38 34 elongation ('%) Shore hardness D 57 ' 49 44 Example 15 (G — Η — I) titanium propylate in amounts which see 0.022 mol. % calculated at 6NT and as With the same device as described a heat stabilizer was used 4,4-bis («, a- above, and using the same procedures as in previous dimethylbenzyl Diphenylamine (Naugard 445) Examples were prepared by copolyesters - in an amount corresponding to 0.95 % wt. ve which had a low and varying hardness relationship to PTMEG in tests G and H; and phase, by reaction of 6NT, 1,6-hexanediol (molar in an amount corresponding to 3.3 % w / w ve ratio of 1,6-hexanediol to 6NT = 2,1) relationship to PTMEG in test 1. by polyoxytetramethylene glycol (PT- Table 8 shows the technological and physical MEG), which had an average molecular weight non-chemical properties of products. noist 1000. As catalyst hy, l is used iso- TABLE 8 Example G H AND mole% PTMEG 60 80 90 polycondensation time (min.) 120 145 240 intrinsic viscosity at 25 ° C 1.79 1.53 1.62 (dl / g) melting point (° C) 210 189 177 hard segments (weight%) 19.3 8.3 3.8 Shore hardness D 48 45 44 permanent load 13.0 11.1 11.2 deformation (MPa) tensile strength (MPa) 41.0 22.7 25.4 elongation ('%) 820 690 865 tensile strain at 25% 6 4 8 extension tensile deformation at 100% 39 42 46

extension

Claims (1)

SUBJECT OF THE INVENTION A process for the manufacture of a thermoplastic elastomer: based on a regularly arranged copolyyeisteramide comprising 2 to 80 percent by weight of segments derived from 1.6-hexanediol, 98 to 20% by weight of polyoxyalkylene glycol-derived segments R'oc — c — R “—C — NH — R“ 'in which R' is an alkyl radical of 1 to 8 carbon atoms and / or an aryl radical of 6 to 10 carbon atoms and / or a cycloalkyl residue of 4 to 10 carbon atoms atoms, R 'and R' 'are divalent hydrocarbon radicals having 2 to 30 carbon atoms, indicated by wheels having an average molecular weight of between 400 and 3500, which segments are linked to each other by ester linkages via a diesteramide derived moiety containing preformed amide bonds having a general formula O O NH-C-R-C-OR 'by heating the mixture of the above diesteramide and polyoxyalkylene glycol with an excess of 1,6-hexanediol at a temperature between 220 ° C to 240 ° C and distilling the mixture thus obtained in a temperature range between 250 ° C to 270 ° C.