DE3247277A1 - BLOCK COPOLYMERS BASED ON PIVALOLAKTON AND METHOD FOR THE PRODUCTION THEREOF - Google Patents

Description

Description

Block copolymers based on pivalolactone and process for their production

It is known that it is possible to use block copolymers with the pattern A-B-C, in which A is styrene, B is a diene and C is pivalolactone (US Pat. No. 3,557,255). »

These polymers have thermoplastic elastic properties and show Eigenschaftmdie of their zweipbasigen Nature (hard and soft) depend, "The product _(f, the appropriate separation of the two phases and a satisfactory interaction between the regions of the hard phases (2 of the same phases in polymers ABA- type -2 _s different phases at P ^ mers from ABC type) shows _i! has satisfactory properties. the transition temperature of the "hard" blocks

;, is an essential parameter "in the sense that there are higher

the transition temperature in general enables that the polymers show their properties at higher temperatures®

The ABC polymers claimed in US Pat. No. 3,557,255 have defined properties which, however, are limited to the transition temperature, which is too low for the vitreous hard phase A (approximately 90 ^° C.)

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• · ■ · «ο ee« «

ⁱ ·

Polystyrene blocks.

The object of the invention consists in the synthesis of products in which the C block is a high-melting point is crystalline hard phase (values between 160 ° C and 23O ° C in accordance with the segment length) and the block B is a "soft" phase of the diene type (also hydrogenated), A an amorphous and / or crystalline phase with a high transition temperature (glassy) can be equal to or higher than 40 C to to give the possibility of obtaining thermoelastic products with improved properties. According to the invention The products obtained are block copolymers of the ABC pattern, where A is a block (sequence) of aromatic Polyvinyl and / or polyisopropaayl (units) with the exclusion of styrene, B a polydiene block (sequence) and / or a hydrogenated derivative thereof and C is a polypivalolactone block (sequence), x, y and ζ integer Are numbers indicating the monomer units in each block.

The structures of the various blocks can be given by the following formulas:

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! ^ coo noes

οοο s> ο aa o co

Ω rs

β ■ "» C Q

Units for block A:

and various possible isomers thereof.

Units for block B ₁

c = GH—

-f- ^cH ₂ -

gh

CH,

where R is -H or -CEU Units for block C:

S ^H ₃ 9 ι

.CH - C - C - 0-4 - ^dH 3

O CH ₃

a j 3

-C - C-CH CH ^:

• «·

As a function of the different values of x, y and ζ one obtains products with different technological properties.

In particular, the value of ζ can even be very small and even amount to only a few units (^ 5). The connections are made by a staged process which is schematically as follows can be represented:

step 1

This first stage is to polymerize the vinyl aromatic monomer identified above with or without apolar solvent and / or co-solvent (polar but added in the following stages of stage 2 if it is desired, the polydiene block with predominantly 1-4 structure). The reaction scheme can be given as follows sec.Butyl -Lit π dk-Methylstyrol—> sec-butyl- (d ^ - methylstyrene) Li.

It should also be taken into account, however, that the polymerization of c * «- methylstyrene is an equilibrium polymerization which is a function of both concentration and temperature, and that χ is equal to or less than η.

Level 2

The second stage relates to the addition of the diene to the product formed in the first stage according to the following reaction scheme
sec.BUT- (dt-methylstyrene) _x Li + y diene ■>

sec.BUT - (^ / - methylstyrene) (diene) Li.

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"ο ο ο ETb o ^c

The addition of the diene must be carried out carefully during the initial step of this second stage in order to avoid depolymerization of the first block (as a result of dilution) and to reach a final state (complete conversion of the diene) at which stirring of the solution is sufficient, to enable the following stage to be carried out "In addition, the" living "state of the polymer must not be disturbed _o The microstructure of the diene is due to the presence or absence of polar activators"

Level 5

The third stage can be summarized as follows

sec “BUT (^ - styrene) _x - (diene) Li + CO ₂ --_— y

COOLi

sekoBUT (cS— styrene) _χ (dien) COOLi sekoBUT (^ - styrene) _x (dien) _y COOH - sekoBUT (d— _{styrene) v} (dien WPVL) ₁₇

This procedure allows _; adding the pivalolactone block (C) to the AB-COOH polymer _; which has been provided homogeneously with functional groups, to be carried out in a well-defined manner while achieving considerable advantages over the process described in US Pat. No. 3,557,255

The production of the products according to the invention will now be described in detail

1) Making the "A" block

In accordance with the type of monomer used, the stage of polymerization is carried out in the presence or absence

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the presence of a solvent carried out using or not using polymerization activators, taking into account the type of product to be manufactured.

In the case of dL-methylstyrene, for example the polymerization stage preferably as bulk polymerization carried out at room temperature or in solution at a lower temperature.

Alkali metal alkyls, their amides and hydrides, can be used as initiators.

The commonly used activator is sec-butyl-Li, but also ethyl-lithium, .n.propyl-lithium, isopro pyl-lithium, tert-butyl-lithium and amyl-sodium can be applied.

The use or non-use of aliphatic, cycloaliphatic ^ aromatic and alkylaromatic Solvents, non-polar solvents, aprotic Solvents which can allow a "living" polymerization of the above-mentioned monomers are determined are given by the value for the T temperature of the latter, where T is their "limit" temperature ("ceiling" temperature), which is characteristic of each individual monomer and represents the temperature above which a certain monomer can no longer be converted into a polymer.

The polymerization temperature for the different compounds that are used is also determined by their T value. As generally is the applicable operating range between -80 and +150 C, a range is preferably from -30 to +80 ⁰ C.

Ii

0 Cl © (J

σ ο O
gg ο ο ο

The monomers are selected from the vinyl compounds (except styrene) and the allfcnylaromatic compounds _o In particular, cL-Methyl ™ styrolp vinylbiphenyl, isopropenylMphenyl, vinylnaphthalene and isopropenylnaphthalene are used, whereby the various possible isomers are included o The degree of polymerization _{ΰ of} the appropriate -. Time (at leisure) (living polymer) ₀ is selected in accordance with the type of product desired so that any desired hard phase to soft phase ratio is achieved (see item 2 below) ®

2) Make the "B" block

The diene is added to the living polymer of the preceding paragraph with the counterion Li Na or K _s in accordance with the type of initiator used and to 'receives the AB-Block.bei the diene structure is influenced by the nature of the counterion and the type of the solvent used

The addition must be carried out under such conditions that the living character of block A and the monomer-polymer balance of the same block A are not modified (if A consists of monomers with low T values), _etc.

If there is no chain-terminating substance, the polymerization of the diene can be carefully terminated and all of the diene is built into the polymer.

The molecular weight of the B block is proportional to the relative amount of diene monomer and the number of survivors Α-chains that are present in the system.

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■ ··· ··· · 4 fry, -! tio «· ■ ···

Generally speaking, aliphatic, cycloaliphatic, aromatic and alkyl aromatic become apolar and aprotic solvents are used.

If the block or sequence A consists of monomers with low T values, as above at the beginning of this

Section stated, a blocking reaction must be initiated before the dilution with a solvent, for example to block the polymethylstyrene end with butadiene units, in order to avoid the monomer-polymer balance shifting due to the dilution towards the monomer. Then you can start with the dilution without worsening the result of the polymerization. In general, the temperature range is from -50 to +150 ⁰ C, with a range of 0 ⁰ C to 60 ° C is preferred.

The dienes that are generally used are those containing up to 12 carbon atoms and preferably 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene (piperylene), 2-methyl-3-ethyl-1,3-butadiene, 3-methyl-1,3-pentiene, 1,3-hexadiene, 2-methyl-1,3-hexadiene and 3-butyl-1,3-octadiene.

3) Make the "C" block

Starting from the living polymer AB as obtained in Step 2, the following reactions were made carried out

i) AB "+ CO ₂ - >>AB-f-COO" + H ⁺ > AB-f-COOH

ii) AB-f-COOH + NR ^ OH> AB " ^f " COO "NR £

iii) AB-f-COO "NR ^ + PVL -> ABC

Products were obtained in which the distribution of the pivalolactone segments through all chains of the AB-

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DOOO C

c η β α
; β α- © οβ 0OC

Block polymer was achieved quite evenly.

The introduction of functional carboxyl groups in the AB polymer _{according to the equation i) is carried out by contacting the living polymer AB with a large excess COp _s dissolved in aliphatic and / or cycloaliphatic solvents, and operating at a temperature between -50 ⁰ C and +20 ⁰ Cp whereby the preferred range is between - = 5 ° C and +5 ⁰ C for a few hours »

The carboxyl group is released by treatment with Brönsted acids

The polymer thus obtained can be used as such for the subsequent grafting stage (see below) of the pivalolactone block, but it can also be hydrogenated beforehand Hydrogenation to obtain well-defined elastomeric products. = The product of reaction l), dissolved in tetrahydrofuran and / or mixtures thereof with aromatic, aliphatic and cycloaliphatic solvents, is induced with tetraalkylammonium bases of the type WR ¹ R ¹¹ R ¹¹¹ R ^ OH where R ¹ ^ R ^11, R ¹¹¹ and R ^IV are the same or different and each is alkyl of 1 to 8 carbon atoms is a few minutes to react at room temperature ", wherein the ratio between COOHsBase 1SO _s 5 and 1: 1 liegte

The addition of pivalolactone (sequence iii) j in varying amounts in accordance with the kind of the desired product, place with quantitative yields if stattι at temperatures between +20 and + 6O ⁰ C

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a few hours are worked. This allows an even distribution of PVL (pivalolactone units) can be achieved within the polymer chains.

The invention is illustrated in more detail by the following examples.

example 1

A tubular glass reactor, which is tightly closed and has a volume of about 1 liter and is provided with a stirrer nitrogen inlet, pressure and temperature indicators and an inlet for the reagents, is filled with 50 ml of C 1-4 methylstyrene and 0.65 mmol of sec-butyl -Li loaded. The polymerization lasts 1 hour and 45 minutes at room temperature, after which 2 g of butadiene are introduced and the reaction can proceed for a further 15 minutes at room temperature. 300 ml of cyclohexane and 34 g of butadiene are then added and the reaction can ^{proceed at 60 °} C. for a further hour. After the reaction is complete, the polymer solution obtained in this way is slowly transferred at 100 ° C. to a nitrogen-filled reactor containing 20 ml of cyclohexane saturated with COp (in a stream of CO _{2 gas).} After one hour, the mass is treated with HCl, then washed to neutrality and the product provided with functional groups (50 g) is precipitated with methanol. The product has the following composition (H-NMR spectrum against CDCl3):

= UMethylstyrene C ^ STY) = 28% by weight (15.2 Mo 1-96) Butadiene (BUT) = 72% by weight (fractions 1-2 = 9 mol-Ji) Fractions ^ - 4 = 75.8 mol%

Molecular weight: 77,000 g / g mol. *) (Areas)

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QOOO 0 O

During the second stage, 47 g of the last-named polymer are dissolved in 250 ml of toluene and 250 ml of tetrahydrofuran (THF), 0.5 mEq of tetrabutylammonium hydroxide (T ₀ BoAoI ₀ ) is added and the mixture is left to react for 15 min at 60 ° C. Finally, 3 ml of pivalolactone (PVL) are added and the reaction can take place for another 3 hours at the same temperature. By adding a few ml of hydrochloric acid and precipitating with methanol, 50 g of a product of the following composition are isolated?

PVL = 6 Gewo- ^ S dU-STY = 28 Gew _o -? 'O and BUT = 66 Gew "-%"

The differential thermal analysis shows 3 transitions at -87 ⁰ Cp at -150 ⁰ C to + 16O ⁰ C and at +207 ⁰ C (melting), which can be assigned to polybutadiene with a high degree of crosslinking 1-4 (sharp transition ) to Poly-4, -STY (not well defined) and to Poly-PVL (sharp transition) _o The samples for the technological investigations were cut out of plates between two aluminum plates that had been treated with a silicone release agent

"Been en ,, were,,. ... _ _Ί , _ formedο The forming conditions can be summarized as follows?

Temperature 240 ⁰ C - pressure 30 daW / cm - preheating 10 min - FoimeniO min - cooling under running water at room temperature where a maximum cooling rate (initially) of 40 ° C / min is obtained has fallen »

The samples for the tensile strength tests were taken from a 1 mm thick plate using a DIN S 3 A die The strength tests were carried out with an Instron test device according to the DIN 53504 standard carried out at a speed of 200 mm / min »The guidance was carried out at expansion intervals *) (lead)

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• ·

read from 50 %. The curve obtained is designated as 1 in FIG. 1.

The thermodynamic and mechanical behavior was carried out with a Rheovibron DDV II viscoelastometer from Toyo Instruments at a frequency of 110 Hz with a heating rate of 2 C / min. The regulation of the temperature was carried out with a gas thermostat (nitrogen) of TNO, which results in a high accuracy so as +0.2 ⁰ C.

The thermodynamic and mechanical performance is summarized in FIG. The glass transition (peak of the loss factor tan (f) at -74 ° C is obvious and is characteristic of polybutadienes with a vinyl unit content of less than 15 % » Such a microstructure of the elastomeric component guarantees the elastic behavior of the material down to such low temperatures like -30 ⁰ C.

At the opposite end of the beginning of the transition is of the poly-cL-methylstyrene s visible near -100 ⁰ C, and more and more evident. The tests are interrupted at +170 ⁰ C, due to a Zusammenfaliens of sample: Such a collapse occurs in commercially available styrene-butadiene-styrene copolymer at about 90 ⁰ C.

The range of the relative constancy of Young's modulus E ¹ extending from about -30 ⁰ C to about +120 C, and this means a noticeable metallic improvement / over styrene-based copolymers which do not exhibit a drop at temperatures in excess of 80 ° C.

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r σ ¹ ^ O

per »c.-oQ <oo ΓΌ ρ -ο ο ο ο a o ο

The measurement of the stress release under deformation was carried out with a Instron tester on round samples with a Diameter of 16 mm and a thickness of 6 mm.

A 25% deformation was achieved by pressing at a speed of 50 mm / min. » The drop in voltage as a function of time is given in Fig. 3 for various test temperatures (the measurements were carried out using the Instron conditioning chamber) ο The retention of elastic properties as a function of time and temperature is significantly lower than with styrene-butadiene-styrene block copolymers _o In particular, the voltage drop is at 10O ⁰ C!
mer at 40 ⁰ C ₁ ,

fall at 10O ⁰ C slow r _f based on the SBS "* Copoly ~

1 shows a diagram in which the stress (^, given in MPa) is plotted on the ordinate and the deformation £ _s is plotted in% on the abscissa (o) _o .

Fig. 2 shows in practice> the dynamic mechanical VeAaltsider sample of Example 1. On the abscissa the temperature T is given in degrees Celsius «, The ordinate on the left is in logarithmic Scale and indicates the moduli of elasticity E ', expressed in MPa (o). The ordinate on the right Page is also on a logarithmic scale and specifies tan ^ as a dimensionless size (o).

Fig. 3 shows a diagram in which on the ordinate the normalized voltage ^ t / ö "ο is indicated, the di-

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is dimensionless) and on the abscissa in the logarithmic The scale is the time t, expressed in s: The curve shows the behavior of the sample according to Example 1.

Example 2

In the reactor described above, 50 ml of d - STY and 0.74 mmol of sec-butyl-Li are added and the polymerization Carried out for 1 hour and 15 minutes at room temperature. Then 4 g of butadiene and after 5 min 350 ml of cyclohexane and 25 g of butadiene were added and the polymerization was carried out at 60 ° C. for 1 hour.

The procedure is then the same as in Example 1 and there are 43 g with functional COOH groups Insulated polymer provided with the following properties: dL-STY 32.5 wt. 96 (18.2 mol%) - BUT 67.5 Weight-96 (portion 1-29 mole-96, portion 1-4 72.8 mol-96) the molecular weight measured by the G.P.C. is 56,000 g / gmol. Such a polymer will be like

given above, dissolved in toluene / tetrahydrofuran (1: 1 volume) and with 0.48 raEq. TBAI (15 min at 60 ° C) and 2 ml of PVL (2 h .for 60 ⁰ C) treated. According to the method described above, 45 g of a product of the following composition were isolated: PVL 4.0 % by weight - 31% by weight - 96% by weight and BUT 65% by weight.

The differential thermal analysis shows the expected transitions at -87 ° C (BUT), +150 ⁰ C - + 16O ⁰ C ^ L-STY) and 197 ⁰ C (PVL).

The tensile properties of this product are indicated by the number 2 in FIG. This product also shows an increase in the area with rubbery behavior, both in terms of temperature and time, compared to commercially available styrene-butadiene-styrene copolymers.

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Example 3

In the above beschrje enclosed reactor, 200 ml of n-Heptani, 12 g of "t-STY and O ₅ 5 mmol sec" butyl-Li gegebenο The polymerization will be for 3 hours at -78 ⁰ C performed Dam 28 g of isoprene (IP) together with 100 ml of n-heptane are added and the temperature is gradually increased to room temperature, whereupon the polymerization is carried out for 2 hours at 60 ° C. After the polymerization stage is complete, the viscous polymer is placed in a nitrogen-filled reactor with a suction lifter _y containing n-heptane which is saturated with gaseous carbon dioxide (anhydrous) and by application

■ 15 of the usual process, 40 g of a functionalized product of the following composition are obtained (determined by H-NMR spectrum against CDCl ₃ ) ^ Jc-STY 30 wt ₀ - / o (19.8 mol-96), IP 70 wt. 96 (portion .3-4 8.0 mol- # and portion 1-4 (or 4 - 1) 72.2 mol-50 ο

The molecular weight) as determined by GPC is 84,000 g / gmol and 40 g of this polymer are dissolved in the usual solvent mixture _{and, as indicated ^ with T 0 BoAoI 0} (O ₅ , 4 meq.) And then with PVL ( 2.5 g). If one works as indicated above, 42 _P 5 g of a polymer of the following composition “PVL 5 * 9% by weight , ^ L-STY 28.2 % and IP 65 3 9% by weight are obtained .- #.

The differential thermal analysis' clearly shows the transitions _t demPolyisopren (-68 ⁰ C), poly-JL-STY (+150 ⁰ C to + 165 ° C) and PoIyPVL (+209 ⁰ C) can be assigned _o

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ο jf / r ο * *

tads. ·· - «Kfioouo» ·. ·. <

Example 4

50 ml of cyclohexane and 0.5 mmol of n-butyl-tetra-methyl-ethylenediamine-sodium (TMEDA) in cyclohexane are placed in the device described above. The polymerization is carried out for 1 hour at + 5 ° C. and 2 g of butadiene are then added and the reaction can take place for 5 minutes at the same temperature (+ 5 ° C.). Then 26 g of butadiene in 300 ml of cyclohexane are added and the polymerization was conducted for 1 hour at 6O ⁰ C.

After completion of the polymerization stage, the Functionalization carried out with COp and one obtains 40 g of a product of the following composition: C = L-STY 30% by weight - BUT 70% by weight (the 1-2 structure predominates).

The molecular weight is 92,000 g / gmol (by GPC). Then work is carried out as described above by treatment with TBAI (0.4 mlq.) And PVL (3 ml). 43 g of a polymer are obtained with the following contents: c ^ -STY 28% by weight , BUT 65% by weight and PVL 7% by weight .

The Differential-Thermoanaly.se (DTA) shows the transitions of polybutadiene with a high vinyl content (highvinyl polybutadiene) (about -30 ° C) from dL-STY (not very sharp) in the range from +150 ⁰ C to +160 ⁰ C and poly -PVL (hot) at + 207 ° C

Example 5

The experiment of Example 4 is repeated with the only difference that the solvent is diethyl ether is, where K- ^ cumyl in the same proportion-

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sen as used in the previous examples. The results are comparable »

Example 6

A solution of 6 g of p-vinyl biphenyl in 150 ml cyclohexane is added by O ₈ 3 mmol sec-butyl-Li, and the polymerization was carried out for 3 hours at a temperature of 60 ⁰ C "After completion of this stage 14 g of butadiene was added and the Polymerization carried out for a further hour at 60 ° C. The polymer is functionalized with COp, the procedure being followed as stated above. 20 g of a product of the following composition are isolated (H-NMR against CDCl ₃ ) S p-vinylbiphenyl 30 wt. 96 (11.4 mol%) - BUT 70 wt. -56, (1-2 structure 8.9 mol-96 1-4 structure 79 »7 mol%) _o The molecular weight (according to GPC) is 57,000 g 28 wt .-% # and BUT p-vinylbiphenyl 65 - PVL 6 "5 wt _#: / gmolo by reaction with TBAI (0.2 mitq _o) and 1.15 g PVL is obtained 21.4 g of a PoIymers the following composition "5 wt. -96. The differential thermal analysis shows the expected transitions for butadiene (-85 ° C) for p'-vinylbiphenyl (+161 ⁰ C) and for PVL (+209 ⁰ C) ₀

Example 7

The above experiment is repeated with the only difference that 2-vinylnaphthalene is used. A product is obtained with a composition similar to that of the product according to Example 6. The differential thermal analysis (DTA) shows the expected transitions, namely -85 ° C (PolyBUT) +151 ⁰ C (polyvinylnaphthalene) and +205 ⁰ C (PolyPVL).

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• * f «f * · β && a

O * * OO

G ·· «·« O Q Ώ

0 * · · 0 0 0

AQO · · · · <# · · · »9 η η Ot) O

- aar -

Example 8

The polymerization stage is carried out in 50 ml of tetrahydrofuran at -78 ° C
naphthalene with n-butyl-Li,

furan carried out at -78 ° C: 10 g of 2-isopropenyl-

Then 2 g of butadiene and then 28 g of butadiene in 300 ml of cyclohexane are added at room temperature and the polymerization is carried out ^{at 60 ° C. for about 1 hour.} After this stage has been completed, the functionalization with COp is carried out by the process as described above. The polymer with the functional COOH groups (40 g) contains 75% by weight of butadiene with a predominantly 1-2 structure. Such a polymer is hydrogenated under normal conditions with palladium on activated carbon (10% Pd). The H-NMR spectrum shows the complete absence of unsaturated bonds. The product is then used to graft the PVL block (2.5 g) by the method with TBAI (0.25 mmol). 42.5 g of a polymer of the following composition are isolated: poly-2-isopropenylnaphthalene 23.5% by weight, polyPVL 6% by weight and C ₂ -C ^ 70.5% by weight.

In the differential thermal analysis (DTA), the expected transitions can be seen at -60 C (Cp-C ^), + 22O ⁰ C (polyisopropenylnaphthalene) and the melting point of 207 ⁰ C for PolyPVL.

Example 9

The procedure is the same as in the previous example with the only difference that p-isopropenylbiphenyl is used. The process is running

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the same and 42 "5 g of a product are isolated which has the expected composition". The D ₀ T ₀ A ₀ shows the transitions at -60 ⁰ C, + 225 ° C and +209 ⁰ C ₉ that the C ₂ = C, -blocks _/ poly-p - isopropenylbiphenyl and polypivalolactone can be attributed »

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Claims (1)

DIPL.-ING. GERHARD PULS (1952-I971) EUROPEAN PATENTATTORNEYS dipl.-chhm.dr.e.prezherr von pechmann DR.-ING. DIETER BEHRENS DIPL.-ING .; DIPL.-WIRTSCH.-ING. RUPERT GOETZ IA-56 811 D-8D00 MUNICH SCHWEIGERSTRASSE 2 Annio % Enoxy Chimica S _o p "A _o teiefon: (089) 66 20 ji TELEGRAM: PROTECT PATENT telex: j 24070 Claims 1.) Block copolymers from AB _r C_ Τ3Φ, where A "a""/ ^x J ^{Δ Λ} aromatic polyvinyl and / or polyisopropenyl block, B a diene block or a hydrogenated diene block, C y ^z is a polypivalolactone block and x, y υηά ζ mean integers. indicating the number of monomer units in the respective block "wherein the transition temperature for the block A is equal to or higher than 140 ⁰ C liegt0 2o block copolymers according to claim 1, characterized ge kennze ichne t ₉ that the vinyl and / or isopropenyl aromatic compound of block A, is selected from - ^ - methylstyrene , vinylbiphenylj, isopropenylbiphenylj, vinylnaphthalene and isopropenylnaphthalene « 3 »block copolymers according to claim 1, characterized _s that the diene compound of the block B is selected from 1,3-butadiene, Isoprene ,, 2,3-dimethyl-1 _s 3-butadiene, 1,3-pentadiene (piperylene), 2-methyl-3-ethyl ~ 1,3-butadiene, 3-methyl-1,3-pentadiene, 1, 3-hexadiene, 2-methyl-1,3-hexadiene and 3-butyl-1,3-octadieno / 2 4. Block copolymers according to claim 1, characterized characterized in that the diene sequence is hydrogenated. 5. Process for the preparation of copolymers according to Claim 1 to 4, characterized through the following stages: a) Polymerizing the vinyl and / or isopropenyl aromatic Monomers b) adding the diene to the product obtained in step a) c) Introduction of functional carboxyl groups into the AB polymer obtained in step b) by reaction initially with carbon dioxide and subsequent release of the carboxyl function through acid treatment, and d) adding pivalolactone to the polymer obtained in step c) 6. The method according to claim 5, characterized in that g e k e η η, that stage a) and / odsrb) SnGqepswart \ on aliphatic, cycloaliphatic ^ aromatic and / or alkylaromatic apolar aprotic solvents is carried out. 7 «Method according to claim 5, characterized in that stage a) and jOder b) dnQsgefifwart of Initiators from the group of alkali alkali compounds, hydrides or-amidei is carried out. / 3 O OP fl OfJ 0OC.ÖOOO OO OO0O 8ο Method according to claim T _5, characterized in that the polymerization initiator is sec.Butyl-Li » 9ο method of claim 5 p ρ characterized in that the stage a) is carried out at a temperature ranging from -80 to +150 ⁰ C 10 »Process according to claim 9, characterized in that the temperature is between -30 and +80 ⁰ C« 11 ο Method according to claim 5 to 1O ₅ characterized in that step b) is carried out at a temperature in the range from -50 to +150 C ο 12. Method according to claim 11, characterized in that the temperature is in the range from 0 to +60 C is " 13. The method according to claim 5 to 12, characterized in that in step c) the living AB polymer is reacted with a solution saturated _{with CO 2} 14. The method according to claim 13, characterized in that the solvent is selected is made from aliphatic and / or cycloaliphatic solvents <■ 15 »The method according to claim 1 to 14, characterized in that step c) at one V 1 1 V .; ^:: ; V ner temperature in the range of -50 to +20 ⁰ C is carried out. 16. The method according to claim 15, characterized in that the temperature is in the range from -5 to +5 ⁰ C. 17. The method according to claim 5 to 16, characterized in that step d) in a mixture of toluene and tetrahydrofuran is carried out. 18. The method according to claim 5 to 17, characterized in that step d) is carried out in the presence of tetralkylammonium salts of the general formula NR ¹ R ¹¹ R ¹¹¹ R ¹⁷ OH in which R R R and R are identical or different are and each represent alkyl groups having 1 to 8 carbon atoms. 6238