HK1061862A - Use of copolycarbonates - Google Patents

Description

Use of copolycarbonates

The present invention provides stress cracking resistant and impact resistant copolycarbonates having particularly good low temperature properties and good aging stability for use in applications in which particularly good low temperature properties and/or high aging stability are required, for example for use in automobile construction or exterior applications and also for the use of the novel copolycarbonates themselves.

For automotive construction and other exterior applications, it has long been an attempt to find polycarbonates which are as resistant as possible to chemicals and preferably transparent, and which combine low temperature resistance and high aging stability.

Polycarbonates are generally brittle at low temperatures, i.e., they tend to break and lose their notched impact strength.

In addition, the polycarbonates exhibit an ageing effect after storage at temperatures below the glass transition temperature, which depends on the storage time and temperature, with the result that the high energy levels in the notched impact strength are markedly reduced (Bottenbruch et al, "Engineering thermoplastic polycarbonates, Polyacetals, Polyesters, Cellulose Esters", Carl Hanser Verlag, Munich, Wien, New York, 1996, pages 183 or less), i.e.the polycarbonates become brittle as a result.

Copolycarbonates based on 4, 4' -dihydroxybiphenyl and 2, 2-bis (4-hydroxyphenyl) -propane are known from JP 5117382 and are described in EP-A10544407, U.S. Pat. No. 5,983,0938, U.S. Pat. No. 3, 5532324 and U.S. Pat. No. 3, 5401826, which have outstanding chemical resistance, thermal stability and outstanding flame retardancy, and at the same time have the same mechanical properties and transparency as compared with commercially available polycarbonates formed from pure bisphenols. However, there is no indication in the prior art of the particularly good low-temperature properties of these copolycarbonates, let alone whether these polycarbonates have particular aging stability.

It was therefore an object to find transparent polycarbonates which, on the one hand, have improved low-temperature toughness compared with the polycarbonate of pure 2, 2-bis (4-hydroxyphenyl) propane and, on the other hand, combine improved aging stability and improved stress cracking properties.

It has now surprisingly been found that the copolycarbonates according to the invention do not exhibit any ageing effects depending on the storage time and temperature when stored below the glass transition temperature of the copolycarbonate, as a result of which high energy levels in the notched impact strength are retained and the polycarbonate does not become brittle.

This surprising ageing property of the copolycarbonates according to the invention is of particular importance for practical use. Many applications involve continuously alternating thermal stresses. The copolycarbonates according to the invention thus constitute materials which have very good notched impact strength at low temperatures and which do not lose their properties on storage at temperatures below the glass transition temperature as a result of ageing effects.

The invention therefore relates to a process for the preparation of a polymer from 0.1 to 46 mol%, preferably from 11 to 34 mol% and in particular from 26 to 34 mol%, of a compound of the formula (I):wherein R is¹-R⁴Independently of one another, H, C₁-C₄Alkyl, phenyl, substituted phenyl or halogen, preferably H, C₁-C₄Use of copolycarbonates formed from alkyl or halogen, and particularly preferably all representing the same group, in particular H or tert-butyl, and a supplementary amount, i.e. from 99.9 mol% to 54 mol%, preferably from 89 mol% to 66 mol% and in particular from 74 mol% to 66 mol%, of a compound of the formula (II), as materials in fields where particularly good low-temperature properties and thermal stability are required:wherein R is⁵-R⁸Independently of one another, H, CH₃Cl or Br, and X represents C₁-C₅Alkylene radical, C₂-C₅Alkylidene (Alkyliden), C₅-C₆Cycloalkylene radical, C₅-C₁₀A cycloalkylidene group.

The most particularly preferred and per se inventive subject matter is a copolycarbonate formed from 34 to 26 mol%, in particular 33 to 27 mol%, in particular 32 to 28 mol%, more particularly 31 to 29 mol% and particularly preferably 30 mol% of monomers of the formula (I) and supplemented in each case by a make-up amount of monomers of the formula (II).

The percentage data given for the bisphenol monomer refer to the total bisphenol content in the polycarbonate and are defined as 100%. Then, pure bisphenol A polycarbonate is composed of 100% bisphenol A. The proportion of carbonate derived from carbonate or carbonyl halide is not taken into account here.

Preferred, particularly preferred and most particularly preferred are polycarbonates having the preferred, particularly preferred or most particularly preferred compositions specified below.

However, the definitions, quantitative ratios and explanations given above in the general sense or as preferred ranges can also be combined with one another, i.e. in any combination between the respective ranges and preferred ranges. They are suitable for the end products as well as for the corresponding precursors and intermediates.

It has now surprisingly been found that these copolycarbonates have particularly good low-temperature properties on the one hand and also particularly good aging properties on the other hand. They can therefore be used as moldings in all fields in which the polycarbonates known to date are not sufficient in terms of their property profile, for example in the electrical sector and in the construction sector, for cover or glazing, in particular in the vehicle sector as films, sheets, fittings, components or cylinder parts, and also in the optical sector as lenses and data storage devices, and also in household articles, and more particularly where improved thermal stability or chemical resistance in combination with good low-temperature properties and/or aging stability are required. In addition, they can also replace other materials in which ordinary polycarbonates have hitherto not been applicable due to their insufficient low-temperature properties.

According to the invention, good low temperature properties are understood to mean, for example, but not exclusively, good low temperature toughness, since ordinary polycarbonates undergo brittle fracture in notched bar impact tests at low temperatures.

According to the invention, low temperatures are understood to be temperatures below-10 ℃, preferably below-20 ℃, more preferably below-30 ℃, most particularly preferably below-40 ℃ and in particular below-50 ℃.

According to the invention, good thermal and aging stability is understood as meaning, for example, but not exclusively, good notched impact strength after annealing, since ordinary polycarbonates become brittle after annealing and are therefore prone to fracture and cracking.

According to the invention, annealing is understood as meaning storage at a temperature below the glass transition temperature of 155 ℃, preferably in the range from 40 ℃ to 140 ℃, particularly preferably from 60 ℃ to 140 ℃ and most particularly preferably from 80 ℃ to 140 ℃.

Preferred compounds of formula (I) are 4, 4 '-dihydroxybiphenyl (DOD) and 4, 4' -dihydroxy-3, 3 ', 5, 5' -tetra (tert-butyl) biphenyl, 4, 4 '-dihydroxy-3, 3', 5, 5 '-tetra (n-butyl) biphenyl and 4, 4' -dihydroxy-3, 3 ', 5, 5' -tetra (methyl) biphenyl; 4, 4' -dihydroxybiphenyl is particularly preferred.

Preferred compounds of the formula (II) are 2, 2-bis (4-hydroxyphenyl) propane, 1, 1-bis (4-hydroxyphenyl) -3, 3, 5-trimethylcyclohexane and 1, 3-bis [2- (4-hydroxyphenyl) -2-propyl ] benzene, 1, 1-bis (4-hydroxyphenyl) -1-phenylethane, 1, 1-bis (4-hydroxyphenyl) -cyclohexane, in particular 2, 2-bis (4-hydroxyphenyl) propane (bisphenol A) and 1, 1-bis (4-hydroxyphenyl) -3, 3, 5-trimethylcyclohexane (bisphenol TMC), and most particularly preferably 2, 2-bis (4-hydroxyphenyl) -propane (bisphenol A).

One compound of formula (I) (in the case of the formation of binary copolycarbonates) and several compounds of formula (I) may be used.

Likewise, one compound of the formula (II) (in the case of the formation of binary copolycarbonates) and several compounds of the formula (II) can be used.

The starting materials (Edukt) of formulae (I) and (II) may obviously contain impurities due to the synthesis. However, high purity is desirable and desirable, and therefore these materials are used in as high a purity as possible.

The production of polycarbonates and copolycarbonates is generally known in the literature and is also carried out accordingly in the context of the present invention:

according to DE-OS 2119779, the production of polycarbonates is carried out in the presence of monomers of the formula (I), preferably in solution, more particularly according to the phase interface process and the homogeneous phase process.

For the production of Polycarbonates according to the phase interface process, reference may be made, for example, to "Schnell", Chemistry and Physics of Polycarbonates, Polymer Reviews, Vol.9, Interscience Publishers, New York, London, Sydney 1964 and Polymer Reviews, Vol.10, "Condensation Polymers by interaction interfaces and Solution Methods", Paul W.Morgan, Interscience Publishers, New York 1965, Kap.VIII, page 325 and EP 971790.

In addition, they can also be produced in the melt by known polycarbonate production processes (so-called melt transesterification processes), which are described, for example, in DE-OS 19646401 or DE-OS 14238123. In addition, transesterification processes (acetate process and phenyl ester process) are described, for example, in U.S. Pat. Nos. 3,978,4386186, 4661580, 4680371 and 4680372, EP-A26120, 26121, 26684,28030, 39845, 91602, 97970, 79075, 146887, 156103, 234913 and 240301 and DE-A1495626 and 2232977.

The copolycarbonates may have a molecular weight Mw (weight average molecular weight) of 10,000 to 60,000, preferably a Mw of 20,000-55,000, determined by measuring the relative solution viscosity in methylene chloride or in a mixture of equal weights of phenol/o-dichlorobenzene, as determined by light scattering.

The polycarbonates according to the invention can be processed thermoplastically in a conventional manner at temperatures of from 240 ℃ to 380 ℃, preferably from 260 ℃ to 360 ℃. Any moldings and sheets can be produced in a known manner by injection molding or by extrusion. Moldings and extrudates of the copolycarbonates according to the invention are likewise subject matter of the present application.

The polycarbonates according to the invention are readily soluble in solvents, such as chlorinated hydrocarbons, for example methylene chloride, and can therefore be processed, for example, in a known manner to cast films or sheets.

The combination of properties such as thermal stability, good low temperature properties, aging stability and chemical resistance makes it possible to use the copolymers according to the invention for a wide range of applications. Possible applications of the polycarbonates according to the invention include:

1. safety panels, as known, are needed in many areas of construction, vehicles and aircraft and helmet shields.

2. Production of foliens, in particular ski-foilaments.

3. Production of blow molded articles (see, for example, US patent a 2964794).

4. For example for the production of light-transmitting sheets, in particular cavity sheets, for covering buildings, such as railways, greenhouses and lighting installations.

5. Production of traffic light covers or road signs.

6. Production of foams (see, for example, DE-AS 1031507).

7. Production of fibers and wires (see, for example, DE-AS 1137167 and DE-OS 1785137).

8. As translucent plastics having a glass fiber content for light-technical purposes (see for example DE-OS 1554020).

9. Production of precision injection molded small parts, such as lens holders. For this purpose, polycarbonates are used which contain glass fibers and which may optionally additionally contain about 1 to 10 wt.% MoS₂Based on the total weight.

10. Optical instrument components, in particular for the production of lenses for cameras and cinematographic cameras (see for example DE-OS 2701173).

11. As light-transmitting carriers, in particular light-conducting cables (see, for example, EP-A10089801).

12. As an electrical insulating material for wires and sockets and plug and socket joints.

13. As a carrier material for organic photoconductors.

14. For the production of luminaries, such as headlights or light-diffusing panels.

15. For medical applications, such as oxygenators, dialysis equipment.

16. For food applications such as bottles, utensils and chocolate molds.

17. For applications in the automotive sector where contact with fuels and lubricants can occur.

18. For sports articles, such as ski poles.

19. For household articles such as dishwashing devices and letter box housings.

20. For housings such as electrical distribution boxes.

21. For other applications, such as gavage doors or animal cages.

In particular, films can be produced from the high molecular weight aromatic polycarbonates of the invention. These films have a preferred thickness of from 1 to 1500 μm, a particularly preferred thickness of from 10 to 900 μm.

The resulting film may be stretched uniaxially or biaxially in a manner known per se, preferably in a ratio of from 1: 1.5 to 1: 5.

These films can be produced by known film production methods, for example by extruding a polymer melt with a slot die (Breitschlitzd ü se), by blowing in a film blowing machine, by deep drawing or by casting. In this connection, it is possible to use these films individually as such. It is of course also possible to use them to produce composite films in combination with other plastic films according to the usual methods, where in principle all known films can be used as counterparts according to the desired application and the final properties of the composite film. Composites of two or more films can be produced.

In addition, the copolycarbonates according to the invention may also be used in other layer systems, for example in coextruded sheets.

The polycarbonates according to the invention may contain various end groups, which are introduced by means of chain terminators. Chain terminators within the meaning of the present invention are compounds of the formula (III):wherein R, R 'and R' may each independently represent H, optionally branched C₁-C₃₄Alkyl/cycloalkyl radicals, C₇-C₃₄Alkylaryl or C₆-C₃₄Aryl radicals, such as butylphenol, tritylphenol, cumylphenol, phenol, octylphenol, preferably butylphenol or phenol.

The polycarbonates may contain small amounts of 0.02 to 3.6 mol%, based on the dihydroxy compound, of branching agents. Suitable branching agents are compounds having three or more functional groups which are suitable for the production of polycarbonates, preferably those having 3 or more phenolic OH groups, for example as named in EP-A708130, page 4, preferably 1, 1, 1-tris (4-hydroxyphenyl) ethane and isatin biscresol.

Auxiliaries and reinforcing agents can be mixed with the polycarbonates according to the invention in order to modify their properties. Suitable auxiliaries and reinforcing agents include, in particular: heat-and UV-stabilizers, flow aids, mold release agents, flameproofing agents, pigments, ground minerals, fibrous substances, such as phosphorous acid, phosphoric acid, alkyl and aryl esters, alkylphosphonanes (alkyl phosphines), arylphosphinees (aryl phosphines), low molecular weight carboxylic esters, halogenated compounds, salts, chalk, quartz powder, glass and carbon fibers, pigments and combinations thereof. These compounds are described, for example, in WO99/55772, pages 15-25 and Plastics Additives, R.G Graprofile and H.M muller, Hanser Publishers 1983.

Furthermore, other polymers, such as polyolefins, polyurethanes, polyesters, acrylonitrile/butadiene/styrene and polystyrene, can also be mixed with the polycarbonates according to the invention.

These substances are preferably added to the finished polycarbonate in conventional equipment, but the addition may also be carried out at different stages of the production process, if desired.

The following examples are intended to illustrate the invention without, however, limiting it.

Examples

Various polycarbonates were synthesized according to known melt production methods (e.g.as described in DE 4238123) and by the phase interface method (e.g.as described in "Schnell", Chemistry and Physics of polycarbonates, Polymer Reviews, Vol.9, Interscience publishers, New York, London, Sydney 1964) and compared with commercially available Makrolon having comparable viscosities.

The relative solution viscosity was determined in dichloromethane at a concentration of 5g/l at 25 ℃ and was determined by light scattering.

The flexural impact test according to ISO 180/4A (Schlagbiegleverruch) was used to determine the impact strength.

Example 1

A polycarbonate having 30 mol% of dihydroxybiphenyl (DOD) and 70 mol% of bisphenol A was produced by the phase boundary method. Tert-butylphenol was used as chain terminator. The particles had a relative solution viscosity of 1.298.

Example 2

A polycarbonate having 30 mol% DOD and 70 mol% bisphenol A was produced by the phase interface method. Tert-butylphenol was used as chain terminator. The particles had a relative solution viscosity of 1.341.

Example 3

A polycarbonate having 30 mol% DOD and 70 mol% bisphenol A was produced by the melt transesterification process. The product had a relative solution viscosity of 1.28.

Comparative example 1

A polycarbonate having 35 mol% DOD and 65 mol% bisphenol A was produced by the melt transesterification process. The product had a relative solution viscosity of 1.295.

Comparative example 2

A polycarbonate having 25 mol% DOD and 75 mol% bisphenol A was prepared by the melt transesterification process. The product had a relative solution viscosity of 1.295.

Comparative example 3

A polycarbonate having 20 mol% DOD and 80 mol% bisphenol A was produced by the melt transesterification process. The product had a relative solution viscosity of 1.295.

The results compared to the commercially available Makrolon are given in tables 1-2.

Polycarbonate resin	Relative solution viscosity
		Makrolon 2808/58	1.293
Makrolon 3108	1.318
		Example 1	1.298
Example 2	1.341
		Example 3	1.277
Comparative example 1	1.295
		Comparative example 2	1.298
Comparative example 3	1.286

Table 1: comparison of solution viscosities

Polycarbonate resin	Notched impact strength according to ISO 180/4A
					23℃[kJ/m2]	-40℃[kJ/m2]	-50℃[kJ/m2]	-60℃[kJ/m2]
	Makrolon2808/58	90z	8s	9s					7s
Makrolon 3108					95z	11s	8s	8s
	Example 1	82z	56z	58z					60z
Example 2					67z	67z	65z	66z
	Example 3	54z	60z	38z					42z
Comparative example 1					Not measured	35z	26s	20s
	Comparative example 2	Not measured	19s	Not measured					13s
Comparative example 3					Not measured	14s	Not measured	11s

Table 2: comparison of notched impact strength and softening temperature

s-brittle fracture

Ductile fracture

Table 2 shows the excellent low-temperature toughness at-60 ℃ of the copolycarbonates according to the invention of examples 1 to 3.

Storage conditions	Example 1	Makrolon 2808
			At 135 deg.C for 46 hours	52z	8s
At 135 deg.C for 7 days	54z
			At 135 deg.C for 20 days	52z
At 150 ℃ for 2 hours	53z
			At 150 ℃ for 24 hours	53z

Table 3: comparison of notched impact Strength according to ISO 180/4A (in [ kJ/m ]²]Meter)

s-brittle fracture

Ductile fracture

As can be seen from Table 3, the copolycarbonates according to the invention also exhibit a significantly varying property profile after aging. The polycarbonate formed from pure bisphenol A already showed brittle fracture behavior after storage at 135 ℃ for a period of 46 hours, whereas the tough behavior was observed even after 7 days for the copolycarbonates. Moreover, the copolymers exhibit high ductile fracture behavior even when stored at 150 ℃ followed by notched impact toughness testing.

Claims (8)

1. From 0.1 mol% to 46 mol%, preferably from 11 mol% to 34 mol% and in particular from 26 mol% to 34 mol%, of a compound of the formula (I):wherein R is¹-R⁴Independently of one another, H, C₁-C₄Alkyl, phenyl, substituted phenyl or halogen, preferably H, C₁-C₄Alkyl or halogen, and particularly preferably all represent the same group, in particular H or tert-butyl, and a supplementary amount, i.e. from 99.9 mol% to 54 mol%, preferably from 89 mol% to 66 mol% and particularlyUse of from 74 to 66 mol% of a thermoplastic copolycarbonate formed from a compound of the formula (II):wherein R is⁵-R⁸Independently of one another, H, CH₃Cl or Br, and X represents C₁-C₅Alkylene radical, C₂-C₅Alkylidene group, C₅-C₆Cycloalkylene radical, C₅-C₁₀A cycloalkylidene group.

2. Use of copolycarbonates according to claim 1 for external applications.

3. Use of the copolycarbonates according to claim 1 for films.

4. Use of copolycarbonates according to claim 1 for optical applications.

5. Use of copolycarbonates according to claim 1 for medical and food applications.

6. The copolycarbonates according to claim 1, used in the automotive sector.

7. The copolycarbonates according to claim 1, used in the power sector.

8. Copolycarbonates according to claim 1, characterized in that they are formed from 34 to 26 mol% of a monomer of formula (I) and a complementary amount of a monomer of formula (II).