EP1185562A1

EP1185562A1 - Vinylcyclohexane-based polymers

Info

Publication number: EP1185562A1
Application number: EP00929475A
Authority: EP
Inventors: Volker Wege; Friedrich-Karl Bruder; Konstadinos Douzinas; Yun Chen
Original assignee: Bayer AG; Teijin Ltd
Current assignee: Covestro Deutschland AG; Teijin Ltd
Priority date: 1999-05-12
Filing date: 2000-05-02
Publication date: 2002-03-13
Also published as: TW553966B; AU4754200A; ZA200108207B; US6649723B1; KR20010114257A; US20040072980A1; CN1350551A; DE19921941A1; WO2000069920A1; AU763241B2; JP2002544338A; BR0010492A; CA2372130A1; HK1046698A1

Abstract

The invention relates to vinylcyclohexane based polymers with an absolute molecular weight Mw of between 100000 and 450000 g/mol-1 or the mixture thereof with a low-molecular component with an absolute molecular weight of between 1000 and less than 100000 g/mol-1, wherein molecular weight distribution is characterized by a polydispersity index ranging from 1 to 3 and melt viscosity reaches a maximum of 1000 Pa.s, measured at 300° C and a shear rate of 1000 s-1.

Description

Vinylcyclohexane based polymers

Compared to polycarbonate, vinylcyclohexane-based polymers with sufficient mechanical properties show that they are currently used to manufacture optical ones

Data storage can be used in a wide range of low shear rates at the same temperature, a higher viscosity.

For high densities of data storage> 5 G bytes, in particular> 10 G bytes, the exact impression of the pits, which are smaller and denser compared to the optical storage media mentioned in EP-A 317 263, US 4,911,966 and the grooves which are possible today, are essential.

The process described in EP-A 317 263 for the production of vinylcyclohexane-based polymers and their use as substrates for optical disks have a molecular weight which is too low to ensure reliable production (comparative example 1). The mechanical properties of the homopolymers described are not very suitable for the production of optical data carriers.

The process described in US Pat. No. 4,911,966 only leads to partially hydrogenated products <97%, with the predominant examples having degrees of hydrogenation (<86%). According to the prior art, partially hydrogenated systems have poor transparency (DE-AS 11 31 885 (= GB 933 596)). The partially hydrogenated systems mentioned are cloudy and unsuitable for applications as optical substrates into which a laser beam penetrates. The partially hydrogenated systems also have the disadvantage that their glass transition temperature depends on the degree of hydrogenation. For a technical process, the setting of the degree of hydrogenation and thus the thermal properties of the optical substrate can only be achieved reproducibly with considerable technical effort and cost. For the rest, the partially hydrogenated products mentioned in US Pat. No. 4,911,966 mostly have far too low a molecular weight for the reliable production of substrates for optical data storage media.

The cited documents do not report on the quality of the impression of pit and

Groove structures and their basic existence through the substrates mentioned there.

Optimized molecular weights and their molecular weight distribution are essential for adequate mechanical properties with good melt flow properties for the molding of pit and groove structures of the high-density optical data carrier.

If the molecular weight is too high, this can lead to problems with the pit and groove impression as a result of the high viscosity.

The substrates according to the invention made of a vinylcyclohexane-based polymer with a narrow molecular weight distribution or their mixture with a low molecular weight component are distinguished by a high level of mechanical properties with good melt flow properties.

This enables the reliable manufacture of optical plates by injection molding and their subsequent bending and break-proof handling.

Thinner substrates with layer thicknesses of less than 1.1 mm, for example 0.6 mm thick, can be produced with sufficient mechanical properties.

Because of these properties, the materials can be used very well as substrates for optical storage media. For other optical substrates that do not require any mechanical recesses, for example in the form of pits and grooves, adequate mechanics, with low birefringence, low moment of inertia, high heat resistance, high modulus of elasticity, low water absorption, low density, are the result of these substrates are also essential.

The invention relates to polymers of vinylcyclohexane with an absolute molecular weight Mw of 100,000 to 450,000 gmol ^"1 or their mixture with a low molecular weight component with an absolute molecular weight Mw from 1,000 to less than 100,000 gmol ^-1 , the molecular weight distribution being determined by a polydispersity index (PDI = M _w / M _n ) is characterized from 1 to 3 and the melt viscosity is a maximum of 1,000 Pas measured at 300 ° C and a shear rate of 1000 s- ¹ .

Any oligomer content up to a molecular weight M _w of 3,000 gmol " ¹ is not taken into account when calculating the polydispersity index.

Any oligomer content up to a molecular weight M _w of 3000 g mol ^" 'is less than 5% based on the weight of the polymer.

The molecular weight Mw of the high molecular weight polymer (homopolymer) is preferably 200,000 to 450,000 gmol ^"1 , in particular from 200,000 to 400,000 gmol" ¹ .

The molecular weight Mw of a high molecular weight copolymer or block polymer is preferably 100,000 to 400,000 gmol " ¹ , in particular 100,000 to 250,000 gmol ^{" 1} . The molecular weight Mw of the low molecular weight component is generally 1000 to 100,000 gmol ^-1 , preferably from 7000 to 90,000 gmol ^-1 , particularly preferably from 10,000 to 90,000 gmol " ¹ .

The molecular weight distribution of the respective component is characterized by a polydispersity index (PDI = Mw / Mn) of 1 to 3.

In the case of mixtures, the proportion of the low molecular weight component, based on the weight of the mixture of high molecular weight and low molecular weight polymer, is generally up to 70% by weight, preferably 5 to 60% by weight, very particularly preferably 10 to 50% by weight. %.

A vinylcyclohexane-based polymer with the recurring structural unit of the formula (I) is preferred for both the high-molecular and low-molecular component

in which

R ¹ and R ² independently of one another are hydrogen or C _j -Co-alkyl, preferably CC ^ alkyl and

R ³ and R ⁴ independently of one another for hydrogen or for C ₁ -C ₄ alkyl, preferably C ₁ -C ₄ alkyl, in particular methyl and / or ethyl, or R ³ and R ⁴ together for alkylene, preferably C3 or C ^ Alkylene (fused 5- or 6-membered cycloaliphatic ring), R ^{5 is} hydrogen or C 1 -C 6 -alkyl, preferably C 1 -C ₄ -alkyl,

R ¹ , R ² and R ⁵ independently of one another in particular represent hydrogen or methyl.

In addition to the stereoregular head-to-tail linkage, the linkage can have a small proportion of head-to-head linkage. The vinylcyclohexane based polymer may be branched through centers and e.g. have a star-shaped structure.

Comonomers can generally be present in an amount of from 0 to 80% by weight, preferably from 0 to 60% by weight, very particularly preferably from 0 to 40% by weight, based on the finished polymer. Polymers of recurring structural units of the formula (I) are preferred from one or a mixture of

Monomers.

The following comonomers can preferably be used in the polymerization of the starting polymer (optionally substituted polystyrene) and incorporated into the polymer: olefins with generally 2 to 10 carbon atoms, such as ethylene, propylene, isoprene, isobutylene, butadiene, C _j -Cg- preferably C ₁ -C ₄ alkyl esters of acrylic or methacrylic acid, unsaturated cycloaliphatic hydrocarbons, for example cyclopentadiene, cyclohexene, cyclohexadiene, optionally substituted norbornene, dicyclopentadiene, dihydrocyclopentadiene, optionally substituted tetracyclododecenes, ring-alkylated styrenes, α-methylbenzenesolene , Vinyl esters, vinyl acids, vinyl ethers, vinyl acetate, vinyl cyanides such as acrylonitrile, methacrylonitrile, maleic anhydride and mixtures of these monomers.

The polymers can have a linear chain structure and also have branching points due to Co units (for example graft copolymers). The branch Centers include, for example, star-shaped or branched polymers. The polymers according to the invention can have other geometrical forms of the primary, secondary, tertiary, optionally quaternary polymer structure, in this case its so-called helix, double helix, leaflet etc. or mixtures of these structures.

Homopolymers of a monomer of the formula (I) are particularly preferred.

Homopolymers of a monomer of the formula (I) or a copolymer, particularly preferably hydrogenated styrene-isoprene copolymer, in particular block copolymers, which are used either alone or as a mixture, are particularly preferably used for the high molecular weight component.

Homopolymers of a monomer of the formula (I), (block) copolymers, particularly preferably hydrogenated styrene-isoprene (block) copolymers, in particular hydrogenated styrene / isoprene, are preferably used for the low molecular weight component

(Block) copolymers with preferably 3 to 8, in particular 3 to 5 radial members used. The low molecular weight component can be either a polymer or a mixture of these polymers.

The vinylcyclohexane-based polymers can have an atactic, predominantly synotactic and predominantly isotactic diad configuration.

Amorphous substrates with a predominantly syndiotactic configuration of the methylcyclohexane units are also preferred, characterized in that the amount of diads is greater than 50.1% and less than 74%, very particularly preferably greater than 52% and less than 70%.

Process for microstructure elucidation using ¹³ C- ^! H Correlation spectroscopy of the methylene carbon atoms of a polymer backbone are generally known and are described, for example, by AMP Ros and O. Sudmeijer (AMP Ros,

O. Sudmeijer, Int. J. Polym. Anal. Character. (1997), 4, 39.). The signals from crystalline isotactic and syndiotactic polyvinylcyclohexane are determined by means of two-dimensional NMR spectroscopy. The methylene carbon atom (in the polymer backbone) of the isotactic polyvinylcyclohexane splits signals into two separated protons in the 2 D-CH correlation spectrum and shows the pure isotactic diad configuration. In contrast, syndiotactic polyvinylcyclohexane shows only one signal for the carbon atom C 1 in the 2 D-CH correlation spectrum. The amorphous syndiotactic-rich polyvinylcyclohexane according to the invention has an integral excess of intensity of the syndiotactic diads compared to the isotactic diad configuration.

The VCH polymers are produced by polymerizing derivatives of styrene with the corresponding monomers by radical, anionic, cationic or metal complex initiators or catalysts and then hydrogenating the unsaturated aromatic bonds completely or partially (cf. e.g. WO

94/21694, EP-A 322 731).

The polymers based on vinylcyclohexane are produced in particular by hydrogenation of the anionically or free-radically polymerized styrene derivatives. The polymers according to the invention can optionally have multimodal distributions for the polydispersity range under consideration.

For those familiar with anionic and radical polymerization, poly-dispersities of the prepolymers between 1 and 3 can be set (Braun, D., internship in macromolecular organic chemistry, revised and expanded edition,

Heidelberg, Huethig 1979).

The absolute molecular weights Mw (weight average) of the hydrogenated products are determined by light scattering. Membrane osmosis (vapor pressure osmosis) provide the absolute molecular weights Mn (number average). Another method for characterizing the molecular weight distribution by the polydispersity is the measurement Solution of the relative molecular weights Mw and Mn by gel permeation chromatography.

The process generally leads to a virtually complete hydrogenation of the aromatic and olefinic units. As a rule, the degree of hydrogenation is> 80%, preferably> 90%, very particularly preferably> 99% to 100%. The degree of hydrogenation can be determined, for example, by NMR or UV spectroscopy.

The melt viscosity is determined by a melt viscometer with a plate and cone structure using the oscillation method. The viscosity of the invention

Polymers or the mixtures for 300 ° C. as a function of the shear rate (angular frequency) at 1000 s ^_1 is generally up to 1000 Pa s, preferably from 5 to 500 Pa s, particularly preferably from 10 to 200 Pa s.

The starting polymers are generally known (e.g. WO 94/21 694).

The polymerization can be carried out continuously, semi-continuously or batchwise.

The amount of catalyst used for the hydrogenation depends on the process carried out, which can be carried out continuously, semi-continuously or batchwise.

The ratio of catalyst to polymer is, for example in the discontinuous process, generally 0.3-0.001, preferably 0.2-0.005, particularly preferably 0.15-

0.01.

The polymer concentrations, based on the total weight of solvent and polymer, are generally 80 to 1, preferably 50 to 10, in particular 40 to 15% by weight. The hydrogenation of the starting polymers is carried out according to generally known methods (for example WO 94/21 694, WO 96/34 895, EP-A-322 731). A large number of known hydrogenation catalysts can be used as catalysts. Preferred metal catalysts are mentioned, for example, in WO 94/21 694 or WO 96/34 896. Any catalyst known for the hydrogenation reaction can be used as the catalyst. Catalysts with a large surface area (for example 100-600 m ² / g) and a small average pore diameter (for example 20-500 Å) are suitable. Furthermore, catalysts with a small surface area (for example> 10 m ² / g) and large average pore diameters are also suitable, which are characterized in that 98% of the pore volume has pores with pore diameters greater than 600 Å (for example approx.

1,000-4,000 Å) (see e.g. US-A 5,654,253, US-A 5,612,422, JP-A 03076706). In particular, Raney nickel, nickel on silicon dioxide or silicon dioxide / aluminum oxide, nickel on carbon as a carrier and / or noble metal catalysts, e.g. Pt, Ru, Rh, Pd used.

The reaction is generally carried out at temperatures between 0 and 500 ° C, preferably between 20 and 250 ° C, in particular between 60 and 200 ° C.

The solvents which are customary for hydrogenation reactions are described, for example, in DE-AS 1 131 885 (see above).

The reaction is generally carried out at pressures from 1 bar to 1000 bar, preferably 20 to 300 bar, in particular 40 to 200 bar.

The polymers or copolymers based on vinylcyclohexane according to the invention are excellently suitable for producing optical data memories, preferably with densities of data storage> 5, in particular> 10 Gbytes, based on a disk with a diameter of 120 mm. Additives such as stabilizers and mold release agents can be added to the vinylcyclohexane-based polymers or (block) copolymers.

The following are examples of optical data storage media:

Magneto-optical disc (MO disc)

Mini disc (MD)

ASMO ("Advanced storage magnetooptic")

DVR (thin cover layer) - MAMMOS ("Magnetic Amplifying magneto optical System")

SIL and MSR ("Solid immersion lens" and "magnetic superresolution")

CD-ROM (Read only memory)

CD, CD-R (recordable), CD-RW (rewritable), CD-I (interactive), Photo-CD

Super Audio CD - DVD, DVD-R (recordable), DVD-RAM (random access memory);

DVD = digital versatile disc

DVD-RW (rewritable)

PC + RW (phase change and rewritable)

MMVF (multimedia video file system)

Because of their outstanding optical properties, the polymers according to the invention are furthermore particularly suitable for producing optical materials, for example for lenses, prisms, mirrors, color filters, etc. Furthermore, as media for holographic images (for example check cards, credit cards, ID cards, three-dimensional holographic images) Pictures). The materials can be used as transparent media for inscribing three-dimensional structures, for example from focused coherent radiation (LASER), in particular as three-dimensional data storage or for three-dimensional imaging of objects. Examples

Manufacturing:

Examples 1-4: Hydrogenated polystyrene (h-PS)

The 40 1 autoclave is flushed with inert gas (nitrogen). The polymer solution and the catalyst are added (Table 1). After sealing, the protective gas is then exposed to hydrogen several times. After the relaxation, the respective hydrogen pressure is set and the corresponding one is stirred

Heated reaction temperature. The reaction pressure is kept constant after the onset of hydrogen absorption, the reaction time is defined from the heating of the batch up to the time when the hydrogen atoms are approaching their saturation value.

When the reaction has ended, the polymer solution is filtered. The stabilizer is added, the product is freed from the solvent at 240 ° C. and further processed as granules (Examples 1 to 4, Table 1).

The molecular weights listed in Table 2 can be set by the reaction conditions used, in particular the temperature (Table 1) and the subsequent working-up conditions (solvent evaporation temperature, type of stabilizer and its concentration).

Example 5: Production of poly (StyroI-Block-Co-Isoprene)

The syntheses are carried out using standard inert gas techniques. 138 kg abs. Cyclohexane are placed in a 250 1 reactor. 6.3 kg abs. Styrene is added to the reactor at room temperature. The temperature is raised to 55 ° C., 102 ml (0.255 mol) of n-butyllithium (23% in n-hexane are added to the reactor. The reaction mixture is heated to 70 ° C. and stirred for 30 minutes. 1.4 kg abs. Isoprene and 6.3 kg abs. Section. Styrene is added to the reactor at the same time. The mixture is kept at 70 ° C. for 2 hours. The reaction solution is cooled to room temperature and a solution of 10 g of 2-propanol in 500 g of cyclohexane is added. The polymer solution is concentrated to 16.6% by weight at 40 to 45 ° C. in vacuo.

Example 6: Preparation of hydrogenated poly (styrene block co-isoprene)

22 kg of the polymer solution (Example 5) are transferred to a 40 1 autoclave under nitrogen. After adding 421.5 g of Ni-5136 P (Engelhard) the

Autoclave charged with nitrogen and hydrogen several times. The reaction solution is heated to 170 ° C. at 100 bar. After the heating-up phase, the reaction is run through an automatic pressure device at 150 bar up to the pressure constant and stirred for two hours.

The catalyst is filtered from the polymer solution. The polymer solution is stabilized with 4000 ppm Irganox XP 420 FF, freed from the solvent at 240 ° C and processed as granules.

Example 7: Production of star-shaped poly (styrene block co-isoprene)

1200 g of cyclohexane, 800 g of methyl tert-butyl ether and styrene (350 g, 3.37 mol) are transferred to a 5 1 steel autoclave. Butyllithium (1.24 g, 19.3 mmol) is added to the solution with stirring at room temperature (25 ° C.). The polymerization is carried out at this temperature for 1.5 hours. After that

Isoprene (53 g, 0.77 mmol) was added to the polymer solution. After 1.5 hours, tetramethoxysilane (0.61 g, 4 mmol) is added to the block copolymer solution as a 7.5% strength by weight solution in cyclohexane. The linkage to the star-shaped polymer is carried out at 80 ° C. for 3 hours. Then 5 ml of isopropanol are added. Example 8: Preparation of hydrogenated star-shaped poly (styrene block co-isoprene)

Nickel on silicon dioxide / aluminum oxide (Aldrich) is added to the polymer solution (Example 7) and transferred to a 5 1 autoclave. It is repeatedly rendered inert with nitrogen. After the pressure has been released, the hydrogen pressure is set to 100 bar, the mixture is heated to 180 ° C. and held at this temperature for 6 hours. The hydrogen pressure is increased again to 100 bar at 80 bar. After the reaction is cooled to room temperature, the catalyst is separated from the polymer solution by filtration and the polymer is dried in vacuo.

Example 9: Preparation of a blend of hydrogenated polystyrene and hydrogenated star-shaped poly (styrene block co-isoprene)

The polymer (Example 8) is in cyclohexane / methyl tert-butyl ether in the ratio

2/1 dissolved as a 20% solution, mixed with the stabilizer Irganox XP 420 FF and mixed with a solution of the hydrogenated polystyrene (Example 4) in a polymer ratio of 50/50. The solvent is removed in vacuo and the dried polymer is processed into granules in an extruder.

The granules are processed into blanks in CD injection molding (Table 4).

Table 1

Hydrogenation of polystyrene

Kataly Reak Water Reactive Stabilizer

In the case of polymer solubilizer.- 10ns- substance- three-dimensional- mass ²⁾ medium mass temp. Pressure time grad. Ppm

No. kg 1 g ° C bar h%

1 5.0 15 1 Cyclo625 ³ ) 180 100 9.7 100 2500 hexane Irganox * 10 l methyl B 561 t-butyl ether

2 5.0 15 1 Cyclo625 ³ ) 160 100 16.5 100 2500 hexane Irganox * 10 l methyl B 561 t-butyl ether

3 4.8 15.1 Cyclo625 ⁴ ) 160 100 17.5 100 4000 hexane Irganox * 9.1 1 XP420 FF methyl t-butyl ether

4 4.8 15 1 Cyclo625 ⁴ ) 160 100 19 100 4000 hexane Irganox * 9.1 1 XP 420 FF methyl t-butyl ether

1) Determined by Η NMR spectroscopy

2) Polystyrene, type 158 k, clear, Mw = 280,000 g / mol, BASF AG, Ludwigshafen, Germany

3) Ni / Sι0 ₂ / Al ₂ 0 ₃ , 64-67% nickel, Aldrich

4) Nι / Sι0 ₂ / Al ₂ 0 ₃ , Nι-5136 P, Engelhard, De Meern, The Netherlands

* The stabilizers are commercial products from Ciba, Basel, Switzerland.

Table 2

Molecular weights Mn, Mw, PDI and their pit or groove impression while meeting mechanical requirements in CD injection molding

A = Standard digital versatile disc matrix, substrates manufactured using Nestal Disjekt 600

B = Standard Compact disc matrix, substrates made using Nestal Disjekt 600

C = High Density Digital Versatile Matrix with measured 93 nm pit depth PDI = polydispersity

^!) absolute molecular weights Mn from the correlation of measured GPC values of vinylcyclohexane-based polymers with molecular weights determined after membrane osmosis

²⁾ absolute molecular weights Mw from the correlation of measured GPC values of the vinylcyclohexane-based polymers with molecular weights determined after light scattering

³⁾ Determined by atomic force microscopy (AFM) '

⁴⁾ Molecular weights Mn and Mw of the prepolymer measured according to GPC '

⁵⁾ 50/50 blend

Depending on the pit and groove depth of the die used, different pit depths can be achieved in the injection molding or injection molding process. The pit depth or groove depth can be varied by device setting, mold temperature and melting temperature of the polymer.

Example 1A (Table 2) shows a good pit impression of the vinylcyclohexane-based polymer. However, the substrates of the optical data storage device produced by injection molding show cracks (so-called cracks or microcracks). The materials characterized in Examples 2 B and 3 A can be produced without the occurrence of cracks or microcracks. The vinylcyclohexane-based polymers according to the invention are ideal optical substrates which at the same time enable good pit or groove molding without the occurrence of cracks at low tool temperatures.

Both Example 4 C (homopolymer) and Example 6 C (copolymer) show a high pit replication (75 nm / 80 nm) at low tool temperatures without crack formation. In addition, Example 6 C (copolymer) has excellent pit replication at low processing and tool temperatures.

Example 9 A (blend of a high molecular weight polymer and a low molecular weight component) likewise exhibits excellent pit replication without crack formation.

The CD substrates according to the invention can be produced without cracks in comparison to Example 1A in a reliable manner.

Claims

claims

Polymers of vinylcyclohexane with an absolute molecular weight M _w of 100,000 to 450,000 g / mol " ¹ or their mixture with a low molecular weight component with an absolute molecular weight of 1000 to less than 100,000 g / mol ^-1 , the molecular weight distribution being based on a polydispersity index of 1 to 3 is characterized and the melt viscosity is a maximum of 1,000 Pa-s, measured at 300 ° C and a shear rate of 1,000 s ^_1 .

Polymers according to Claim 1, containing, as vinylcyclohexane-based polymer, a polymer having the recurring structural unit of the formula (I)

in which

R ¹ and R ² are independently hydrogen or C _j -CG-alkyl,

R ³ and R ⁴ independently of one another are hydrogen C _j -Cg-alkyl or together represent alkylene, and

R ^{5 represents} hydrogen or C 1 -C 6 -alkyl,

and optionally containing at least one comonomer selected from the group consisting of olefins having 2 to 10 carbon atoms, C ₁ -C ₄ alkyl esters of acrylic acid, C _j -C ₄ alkyl esters of methacrylic acid, unsaturated cycloaliphatic hydrocarbons, optionally substituted tetracyclododecenes divinylbenzene, vinyl esters, vinyl acids, vinyl ethers, vinyl acetates and vinyl cyanides.

3. Polymers according to claim 1 or 2, characterized in that they are present as homopolymers, copolymers or block copolymers.

4. Polymers according to claims 1 to 3, wherein in the case of mixtures with a low molecular weight component, the proportion of the low molecular weight component based on the weight of the mixture of high and low molecular weight polymer is up to 70% by weight.

5. Use of the polymers according to claim 1 to 4 for the production of moldings and optical materials.

6. Use of the polymers according to claims 1 to 4 for the production of optical data memories.

7. Shaped body obtainable from polymers according to claims 1 to 5.

8. Optical substrate containing polymers according to claim 1 to 4.