DE3435334A1 - METHOD FOR PRODUCING BLOCK COPOLYMERS BASED ON PIVALOLACTON - Google Patents

Description

Process for the preparation of block copolymers on the Based on pivalolactone

It is known that it is possible to prepare ISt ₁ block copolymers of the ABC type in which A = styrene, B a diene and C s is PVL (US Pat. No. 3,557,255).

These polymers have thermoelastomeric properties, which depend on their multi-phase nature and the presence of "hard" as well as "soft" phases. The products, by a good separation of the hard and soft phases and by a good cohesion between the areas of the hard phases (which in the case of ABC polymers can be of two different types) 5 show generally good thermoelastomeric properties. Also the transition temperature of the hard Ranges is an important parameter in the sense that high transition temperatures are required for the thermoelastomers are necessary so that they show their rebound elasticity properties even at high temperatures.

In connection with the above, have the beschriebenenABC in US Patent No. 3,557,255 products interesting properties, but by a relatively low transition temperature (about 90 ⁰ C)

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the vitreous hard phase, which consists of polystyrene blocks ^ are limited. In DE-OS 32 47 277 is the Production of block polymers of the ABC type described,

* BlockLy where A is a homopolymeric sequence / 'of a vinyl or isopropenyl aromatic monomer, B a sequence of a diene monomer (or its hydrogenation product of same sequence) and C is a homopolymeric sequence of PVL, through a step-by-step process that is schematic can be specified as follows:

1st stage

In the first stage, the polymerization of the vinyl aromatic or isopropenyl aromatic monomer is carried out in The presence or absence of a non-polar solvent and / or a polar co-solvent is carried out (This is not added if the polydiene block predominates in the subsequent second stage 1-4 structure).

The reaction scheme can be given as follows:

R-Li + η STY ^ R- (STY) Li + (n-x) STY,

where: χ <n,

STY = vinyl or isopropenyl aroma

table monomer, R = alkyl.

The polymerization can be carried out as in the case of α-methylstyrene be an equilibrium polymerization as a function of concentration and temperature.

2nd stage

In the second stage the diene is added to the product formed in the first stage, according to the following Scheme:

R- (STY) Li + y diene> R- (STY) - (diene) -Li.

χ xy

The addition of the service must begin at the beginning of the second stage carried out carefully to avoid depolymerization of the first block (due to dilution) and to reach a final state (complete conversion of the diene) in which stirring the solution is sufficient, so that the following stage can be carried out.

In addition, the "life" of the polymer must not be impaired.

The microstructure of the diene is determined by the presence or absence of polar activators.

3rd stage

The third stage comprises a series of reactions (1 a to Id), which can be specified as follows: 25th

R- (STY) _x - (diene) Li + Co ₂ -> - (la)

^ R- (STY) - (diene) -COO-Li

R- (STY) - (diene) -COO-Li + H ⁺ -5>"(Ib)

^ R- (STY) - (diene) -COOH + Li ⁺

R- (STY) - (diene) -COOH + NR ^ -OH ^ (Ic)

> R- (STY) - (diene) -COONR '+ H "0

X jf fr c *

R- (STY) - (diene) -COONR '+ ζ PVL ^ (ld)

χ y 4

Il

^ R- (STY) _x - (diene) -CO- (PVL) ₂ -N

It has now surprisingly been found that if a tetraalkyl ammonium salt of the formula NR ' ₄ A is used in the third stage of the process described above, the same stage can be modified in accordance with the following series of reactions (2a to 2c):

R- (STY) _x - (diene) -Li + CO ₃ - ^ - (2a)

^ R- (STY) - (diene) - COO-Li

R- (STY) _x - (diene ■) -COO-Li + NR ^ A-> ■ (2b)

> R- (STY) - (diene) -COONRi + LiA

R- (STY) _x - (diene) -COONR ^ + ζ PVL> (2c)

0 Jl

^ R- (STY) - (diene) -C-O- (PVL) -NR '

The significant advantages of this alternative result from the significant simplification of the process, which thereby become possible:

i) The grafting stage is carried out with the aid of one less reaction, ie reaction Ib is omitted in the formation of the COOH group-bearing polymer and consequently
ii) expensive and cumbersome operations become

the purification and drying of the polymer containing the COOH group, which are necessary _/ to remove the impurities interfering with the subsequent polymerization of PVL, iii) the reactions of the introduction of the COOH group and the grafting of the polymer (2a to 2c) are carried out in a single reaction vessel instead of two different reactors (la to Ib separated from Ic to Id) -

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iv) special materials for the reactors and accessories are not required, as they are necessary for the acid treatments (as for the reaction Ib).
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The alternative method according to the invention and those with it The associated simplifications of the way of working do not lead to a negative change in the properties of the ABC copolymers produced in this way. 10

The synthesis of the products according to the invention is explained in more detail below:

T ... § ¥ 5 ^]}? Se_der_Sequence_A (Block A)

Depending on the monomer used, the polymerization is carried out with or without the addition of polymerization activators carried out with regard to the type of product to be obtained.

Alkyl or amide or hydride derivatives can be used as initiators of alkali metals.

The initiator commonly used is Li-sec.-butyl, but other initiators can also be used favorably, such as:

Li-ethyl, Li-n-propyl, Li-iso-propyl, Li-tert-butyl and Na-amyl.

The use or non-use of aliphatic, cycloaliphatic, aromatic, alkyl aromatic and polar aprotic solvents, which allow the living polymerization to be carried out, can be

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due to the T value of the monomers used (T = upper limit temperature (ceiling temperature), the • is typical for each monomer and the temperature above which a given monomer is no longer can be converted to a polymer).

The polymerization temperature for the various monomers used is also determined by their T value:

The polymerization reaction is carried out 80 ⁰ C, generally at a temperature ranging from -8O ⁰ C to 150 ⁰ C and in particular from -3O ⁰ C to +.

In special cases, such as a-methylstyrene, the Polymerization carried out in bulk at room temperature or in solution at a lower temperature.

The types of monomers employed are selected from vinyl and alkenyl aromatic compounds. In particular, styrene, α-methylstyrene, vinylbiphenyl, isopropenylbiphenyl, vinylnaphthalene and isopropenyl · naphthalene are used, the various possible isomers thereof being included. The degree of polymerization, which is variable as desired (living polymer ) _f , is selected according to the type of product to be obtained in order to obtain a desired ratio between hard and soft phases (see paragraph 2).

2 _Λ §YSthese_der_Fol2e_B (Block B)

The diene is added to the living polymer of the previous paragraph, with Li, Na or K as the counterion are available according to the type of initiator used.

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and the block AB is obtained, in which the structure of the diene (Bloek) is a function of the type of counterion and of the solvent used.

The addition must be carried out under such conditions that the living character of the block A and the Monomer-polymer equilibrium of the same block A (if A consists of monomer (units) with low T values

exists) cannot be changed.
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In the absence of chain-terminating agents, the Conversion of the service completely

The molecular weight of sequence B is proportional to the amount of diene monomer and the number of living chains A. in the system.

In general, aliphatic, cycloaliphatic,

aromatic and alkyl aromatic solvents are used. 20th

If sequence A consists of monomers with low T _c values, as stated at the beginning of this paragraph, a blocking (termination) reaction must be carried out prior to dilution with a solvent, e.g. B. ^ ⁵ of poly-α-methylstyrene at the chain end with butadiene, in order to avoid that the monomer-polymer balance is shifted due to the dilution towards the monomer. The dilution can be carried out without any problems.

Generally, the reaction is carried out at a temperature in

343533A ■ Μ-

-8th

Range from -50 to +150 ⁰ C and preferably from 0 to 60 ⁰ C carried out.

The commonly used dienes are those with 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-pentadiene, 1,3-hexadiene, 2-methyl-1,3-hexadiene and 3-butyl-1,3-oetadiene.

3 ^ §Yi} these_der_F possibly_C (Block C)

Starting from the living polymer AB, which is formed in the second stage _; using reactions 2a, 2b, 2c in the order given, products are obtained with uniform distribution of the segments C of PVL in all chains.

The introduction of functional carboxyl groups according to equation 2a into the polymer AB is carried out by bringing the living polymer AB _{into contact with excess CO 2} in aliphatic, cycloaliphatic, aromatic, polar solvents and / or mixtures thereof is dissolved, working at a temperature in the range from -50 to +100 ⁰ C and preferably from -5 to +25 ⁰ C for a few hours.

In order to accelerate the carboxylation reaction, it is also possible to work under a CO 2 pressure. Corresponding The experimental conditions used may contaminate the functional groups containing polymer occur through AB-BA coupling.

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The polymer AB containing functional groups can be used as such in the following grafting stage (see below) of the pivalolactone block can be used or it can be hydrogenated beforehand. In this case, if that Diene butadiene is the microstructure of the butadiene block chosen so that one after the hydrogenation receives hydrogenated block, which still has elastomeric properties. In the case of hydrogenation, of course Catalysts are used in the homogeneous

'° or heterogeneous phase act. Also the use of Compounds of the tosylhydrazide type in a stoichiometric amount based on the unsaturated bonds present leads to satisfactory results.

The AB-f-COO-Li compoundj dissolved in tetrahydrofuran and / or its mixtures with aromatic, aliphatic and cycloaliphatic solvents is after excess CO "has been removed, reacted with Tetraalkylammonium salts (2b) of the type

1 ? λ 4
NR RR R- A

12 3 4
where R, R, R and R are identical or different and denote alkyl having 1 to 8 carbon atoms and A

Cl ", Br", J ~, CH ₃ COO ", HSO ₄ ", NO ₃ ", NO ₃ "'

0CN ~, SCN ~, BF ₄ "'or CH ₃ -C ₆ H ₄ -SO ₃ ".

The reaction is preferably carried out with a stoichometric ratio of COO-Li to NR '-A, the Take into account the amount of -COO-Li groups already present-

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It is observed at a temperature in the range from 20 ⁰ C to 80 ⁰ C and preferably + 60 ⁰ C, the reaction taking place within different times (from a few minutes to hours), depending on the conditions used, the reactivity and the solubility of the applied Salts.

The addition of pivalolactone (reaction 2c) in different amounts ^ corresponding to the product to be manufactured, takes place with quantitative yields if the reaction is carried for several hours at temperatures ranging from + 20 ° to + 80 ⁰ C. In this way, a homogeneous distribution of PVL in all chains is achieved. These copolymers show the typical properties of the thermoelastomeric products ^

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

The products of the invention are block copolymers

of type ABC where
² ^ χ y ζ

A = an aromatic polyvinyl and / or polyisopropenyl sequence

B = a polydiene sequence and / or a hydrogenated derivative

vat of it

C = a polypivalolactone sequence and x, y, ζ = mean integers that represent the number of Specify monomer units in the respective sequence and can assume the following values: 25 <χ <750

200 <y <300
5 <ζ <200

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l \ 5

The polymers of the ABC type generally have a

x y z

Molecular weight in the range of 20,000 to 200,000.

The structures of the various sequences can be given by the following formulas. Type Ä episodes:

₀
2

CH ^

[3_ _ I J_

- 9 = / _T - - Z ¹ CH -CH- / - -Z-CH - C - /,

- £ CH - CH.-7 -

and their possible isomers

/ Γ Ij _ C = C - C - / -

J-H

where R ^a , R ^b , R ^c , R ^d , R ^e and R ^{f are} identical or different

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At·

are and can be hydrogen and / or alkyl radicals.

CH, O O CH

C - C - O _z / _z - - / - CC -CH ₂ -O J ₇ -

CH ₃ CH ₃

Depending on the different values for x, y and ζ, products with different technical Properties preserved. In particular, the value for ζ can become very small and of the order of magnitude of a few units (> 5).

Example_2

50 cm of ct-methylstyrene and 0.065 mmol of Li-sec-butyl are placed in a tubular, completely closable glass reaction vessel with a capacity of 1 liter, which is provided with stirrers, nitrogen inlet, pressure and temperature measuring devices and a feed device for the reactants. The polymerization is carried out for one hour and 45 minutes at room temperature and then 2 g of butadiene are added and the reaction can always proceed at room temperature for 5 minutes. 300 cm of cyclohexane and 34 g of butadiene are then added and the reaction is ^{continued at 60 °} C. for 1 hour.

At the end of this reaction this becomes polymeric solution

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Kk-

slowly poured into a reaction vessel under a nitrogen atmosphere, containing 300 cm of tetrahydrofuran saturated with C0 ~ from O ⁰ C ^ in a CO ~ streamj.

After 1 hour, the reaction mixture is allowed to reach room temperature heat and by applying a slight vacuum, excess carbon dioxide is completely removed removed. A small portion of this product, which has been isolated and purified, shows (by H-NMR

TO spectrum in CDCl-.) The following composition:

α-methylstyrene (α-Sty) = 29% by weight (15.8 mol); Butadiene (BUT) = 71% by weight (1.2 = 8.5mol 1.4 = 7 S, 6 times)

(g / mol) ■ \ 5 The molecular weight is 75,000 /. To the remaining polymer solution 0.5 meq tetra-butylammonium iodide is added and the mixture was reacted for 1 hour at 60 ⁰ C. The pivalolactone (PVL; 3 ml) is added last and the reaction can proceed for a further 3 hours at this temperature.

By adding a few cm of hydrochloric acid and precipitation with methanol, 52 g of a product of the following composition are isolated: PVL 6% by weight, jα-sty = 28% and BUT = 66% by weight.

The differential thermal analysis shows three transitions at -91 ⁰ C, at +160 ⁰ C and at +209 ⁰ C (melting), the polybutadiene with a high 1,4 content sharp; Poly-a-sty, not well defined; as well as Poly-PVL, correspond sharply. The polymer is completely soluble in cyclohexane after boiling for 16 hours.

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The test pieces for the technological investigations are made from plates pressed between two aluminum surfaces treated with a silicone anti-stick agent.
5

The pressing conditions can be summarized as follows will:

Temperature: 24O ⁰ C

2 2

Pressure: 30 daN / cm (kg / cm)

Preheating: 10 minutes
Shapes: 10 minutes
Cooling: Flowing water at room temperature, which allows for maximum initial cooling speed of 40 ⁰ C / minute.

Pressure release: When the temperature also reaches 30 ⁰ C.

Has.

The test pieces for the tensile strength tests are produced by punching out 1 mm thick plates with a punching tool DIN S 3 A. The tensile strength tests are carried out using an Instron dynamometer according to DIN 53504 standard with a Speed of 200 mm / minute. The tension is measured in elongation intervals of 50%. The receiving Curve is indicated in Figure 1 (·).

The reaction is carried out as in Example 1, the α-methylstyrene polymerizing for 1 hour and 20 minutes and the other stages are carried out in the same way. The polymer containing the COOLi groups (α-methylstyrene = 23% by weight, butadiene = 77% according to the NMR molecular weight 69,000 according to GPCr analysis) Given tetrabutylammonium bromide and the mixture a *) gel penetration chromatography

Implemented at 60 ⁰ C hour. Then the pivalolactone (2.8 ml) is added and the polymerization is continued for a few hours at the same temperature. The same treatment as described in Example 1 isolates a product with the following composition: PVL = 6% by weight, α-Sty = 21% and BUT = 73%. The thermal differential analysis shows 3 transitions at -90 ⁰ C, at +160 ⁰ C and at +208 ⁰ C (melts ^ which could easily be assigned.

The polymer is completely soluble in boiling cyclohexane.

The results of the technological studies of the Test pieces which have been produced as described above are indicated in Fig. 1 (*).

The previous example is repeated with the only difference that instead of tetrabutylammonium- bromide now tetraethylammonium acetate is used. You get a product with the following composition: PVL = 6%, α-Sty = 22% and BUT = 72%. The data of the technological investigations are similar to those of the previous example.

For example £ iel_4

Example 1 is repeated with the only difference that tetraoctylammonium chloride is used.

A product with the following composition is obtained: PVL = 6% by weight, α-Sty = 28% and BUT = 66%.

The data of the technological study of this product are similar to those of the previous examples.

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Claims (3)

PATENT CLAIMS 1. Process for the production of block polymers of type ABC, where x y ζ 5 A is a polyvinyl and / or polyisopropenyl aromatic block B a diene block or hydrogenated diene block Y C is a polypivalolactone block and • j Q x, y, ζ mean integers representing the number of units of the Specify monomers in the respective sequence and can have the following values: 25 <χ <750 200 <y <3000 5 <ζ <200 characterized by the following stages: a) Polymerization of the vinyl and / or isopropenyl aromatic Monomers, 20 b) adding the diene to the product formed in step a), c) Introduction of functional carboxyl groups into the living polymer AB obtained in step B through initial reactions of the Ie-25 benden Polymers AB with carbon dioxide / 2 3 4 3 id 3 3 d) Addition of pivalolactone to the polymer obtained in stage c » 2. The method according to claim 1, characterized in that g e k e η η, that stage a) in the presence of aliphatic, cycloaliphatic, aromatic, alkylaromatic and / or aprotic polar solvents. TO 3. The method according to claim 1, characterized in that step a) in the presence of initiators consisting of alkali alky! compounds, hydrides or amides is carried out. 4. The method according to claim 3, characterized in that that the initiator for the polymerization is Li-sec.-butyl. 5. The method of claim 1 to 4, characterized in that step a) is carried out at a temperature ranging from -80 to 150 ⁰ C. 6. The method according to claim 5, characterized in that the temperature is in the range of -3 0 ⁰ C to + 8O ⁰ C geke η η. 7. The method according to claim 1 to 6, characterized in that step b) in the presence of aliphatic, cycloaliphatic, aromatic, alkyl aromatic and / or polar aprotic hydrocarbon solvents is carried out. / 3 8. The method according to claim 1 to 7, characterized in that step b) in the presence an alkali alkyl, hydride or amide is carried out. 9. The method of claim 1 to 8, characterized in that step b) at a temperature in the range of -50 to +150 ⁰ C is performed. 10. The method according to claim 9, characterized in that the temperature is in the range from 0 to +60 ⁰ C. 11. The method according to claim 1 to 10, characterized g e mark It is ensured that stage c) is carried out with the aid of saturated solutions of CO 2. 12. The method according to claim 11, characterized in that g e k e η η, that the solvent is preferably selected from aliphatic and / or cycloaliphatic Solvents. 13. The method of claim 1 to 12, characterized in that step c) is carried out at a temperature in the range of -50 to +20 ⁰ C. 14. The method according to claim 13, characterized in that the temperature is in the range from -5 to +5 ⁰ C. Geke η η ■. / 4 15. The method according to claim 1 to 14, characterized in that step d) in the presence a mixture of toluene and tetrahydrofuran is carried out. 16. The method according to claim 1 to 15, characterized in that step d) in the presence of tetraalkylammonium salts of the general formula 1234 1234 NR RRRA is carried out, where R, R, R, R are the same or different and each represent alkyl groups with 1 to 8 carbon atoms and A is selected from: Cl ", Br", J ~, CH ₃ COO ", HSO ₄ ", NO ₂ ", NO ₃ ", OCN ~, SCN ~, BF ₄ "and CH ₃ C ₆ H ₄ SO ₃ ". 6288