JP2003527460A - Polycarbonate sheet - Google Patents

Abstract

  (57) [Summary] The present invention relates to a polycarbonate sheet. The polycarbonates according to the invention are produced by an interfacial polycondensation process, and the aqueous solutions of alkali salts of bisphenol used for this purpose have a dissolved oxygen content of 150 ppb or less.

Description

Detailed Description of the Invention

The present invention relates to a polycarbonate sheet, its use for producing glazing and said glazing.

Polycarbonate sheets are used, for example, to produce transparent glass sheets. In this case, it is desirable to use a sheet having the highest light transmittance and the lowest yellowness index. Although it is possible to reduce the Yellowness Index by adding a blue pigment, this is achieved at the expense of light transmission and graying of the sheet. It is important to keep the mechanical properties of the sheet at the highest possible level during weathering of the sheet. The sheets are hailed even after weathering.
It must have high resistance to mechanical action such as.

Polycarbonates can be produced by the so-called interfacial polycondensation method. in this way,
Dihydroxydiarylalkanes (also known as bisphenols), in the form of alkaline salts in aqueous solution, contain phosgene and an inorganic salt or organic solvent such as sodium hydroxide solution in which the product polycarbonate is readily soluble. React in a heterogeneous phase.

For more details on the interfacial polycondensation process for making polycarbonates, see Schnell, Chemistry and Physics of Polycarbonates (Che.
mistry and Physics of Polycarbonates) ", Polymer Revues, Volume 9, Interscience Publishers, New York, London, Sydney 1964
Disclosed in the year.

Polycarbonate sheets known from the prior art exhibit the disadvantages of high light transmission, low yellowness index and insufficient fulfillment of the abovementioned requirements for good retention of mechanical properties during weathering.

Thus, the object of the invention is to produce a polycarbonate sheet which does not exhibit the abovementioned disadvantages of the prior art.

According to the invention, this task is achieved with a polycarbonate sheet.
Here, the polycarbonate is produced by the interfacial polycondensation method, and the aqueous solution of the alkali salt of bisphenol used at that time has a dissolved oxygen content of 150 ppb or less.

The dissolved oxygen content in the aqueous solution of the alkali salt of bisphenol is less than 150 ppb, preferably less than 100 ppb, particularly preferably less than 50 ppb.

Accordingly, the present invention provides a polycarbonate sheet. The polycarbonate sheet of the present invention is produced by the interfacial polycondensation method, and the aqueous solution of the alkali salt of bisphenol used in the method has a dissolved oxygen content of 150 ppb or less.

In addition, the invention is for example for motor vehicles or buildings, especially for greenhouses, winter gardens, for bus shelters, for advertising panels, for signs, protective screens and for window glass of automobiles or for windows or roofs. We also offer transparent glass.

According to the present invention, polycarbonate is produced in a manner in which the other raw materials than the aqueous solution of the alkali salt of bisphenol do not contain a significant amount of oxygen. In addition, the production is carried out by excluding oxygen, as described in DE-A 42 722 72.

For example, in the form of reaction vessels and tubular reactors, large volumes of water are placed in unnatural annular loops and tubular reactors and nitrogen is evenly applied to the reaction vessels to ensure oxygen exclusion. To do.

The polycarbonate sheet of the present invention is, for example, a solid sheet, a hollow sheet (also known as a multiple sheet, for example, a double sheet or a triple sheet), or a corrugated sheet. These are used, for example, as a plate glass material. The sheet is a method generally known to those skilled in the art,
It may be produced, for example, by extrusion or injection molding.

The sheet can then be processed (eg thermoformed or surface modified, such as by applying a scratch lacquer or an aqueous dispersed phase). The present application also relates to shaped articles produced by the method.

In order to produce the polycarbonate for the sheet of the present invention, the dissolved oxygen content is 1
Less than 50 ppb, preferably less than 100 ppb, particularly preferably 50 ppb of an aqueous solution of an unproposed alkali salt of bisphenol is used. This aqueous solution preferably contains bisphenol having a dissolved oxygen content of less than 10 ppb and a dissolved oxygen content of 100 pb.
It is obtained by reacting an aqueous alkali hydroxide solution having a pb of less than pb in an environment where oxygen is excluded.

[0016]   The preferred alkali salt is the sodium salt of bisphenol.

The bisphenols that can be used in the present invention include ketones and other grades of substituents (sec not substituted in the para position and such as cyano, carboxy or nitro groups).
Aromatic hydroxy compounds containing no ond order pigments (eg phenol, o- and m-cresol, 2,6-dimethylphenol, o-tert-butylphenol, 2-methyl-6-tert-butylphenol, o-cyclohexylphenol) , O-phenylphenol, o-isopropylphenol, 2-methyl-6-cyclopentylphenol, o- and m-chlorophenol, 2,3,6-trimethylphenol,
Preferably phenol, o- and m-cresol, 2,6-dimethylphenol, o-te
rt-butylphenol and o-phenylphenol). Phenol is particularly preferred. Ketones having at least one aliphatic group in the carbonyl function are preferred, for example acetone, methyl ethyl ketone, methyl propyl ketone, methyl isopropyl ketone, diethyl ketone, acetophenone, cyclohexanone, cyclopentanone, methyl-, dimethyl- and trimethyl. -It is cyclohexanone. These may contain geminal methyl groups such as 3,3-dimethyl-5-methylcyclohexanone (hydroisophorone).

Highly preferred are acetone, acetophenone, cyclohexanone, and their homologues having a methyl group. Most preferred is acetone. Providing an effective inert nitrogen atmosphere throughout the manufacturing process ensures that the residual dissolved oxygen content in bisphenol is less than 10 ppb.

The bisphenol used in the present invention may further be the following. 3-
(4-hydroxyphenyl) -1,1,3-trimethylindan-5-ol, 1,3-di- (2- (4-
Hydroxyphenyl) -2-propyl) -benzene, and 1,4-di- (2- (4-hydroxyphenyl) -2-propyl) benzene.

A particularly preferred bisphenol is 2,2-bis (4-hydroxyphenyl) propane (
Bisphenol A) and 1,1-bis (4-hydroxyphenyl) -3,3,5-trimethylcyclohexane.

The bisphenol or mixture thereof is preferably scavenged of oxygen (eg, by providing an inert nitrogen atmosphere) and reacted with an aqueous alkali hydroxide solution having a dissolved oxygen content of less than 100 ppb, preferably less than 20 ppb. . The concentration of the aqueous solution of alkali hydroxide is preferably a value at which the concentration of the obtained aqueous solution of the alkali salt of bisphenol is as close as possible to the solubility limit, that is, 15 to 20% by weight, preferably 16.5 to 18.5% by weight. It is within the range. The molar ratio of alkali hydroxide to bisphenol is in particular 1.8: 1 to 2.5: 1, preferably 1.9: 1 to 2.4.
: 1 and particularly preferably 2.0: 1 to 2.3: 1. Bisphenol may be dissolved as a solid in aqueous alkali hydroxide solution. However, it is 20 ℃ ~
It is preferably added directly to the aqueous alkali hydroxide solution as a melt at a temperature of 90 ° C., preferably 30 ° C. to 70 ° C., without going through the solid state.

The aqueous, substantially oxygen free alkaline hydroxide solution used to produce the aqueous solution of the alkali salt of bisphenol may be produced by electrolysis. After manufacture, the aqueous alkali hydroxide solution must be stored and transferred under an inert gas. For use in the method of the present invention, the concentration of the aqueous alkali hydroxide solution obtained during electrolysis is generally reduced by dilution with completely deionized water, which is virtually free of oxygen. Oxygen is usually removed from the completely deionized water in a known manner (for example catalytically, by degassing or by stripping an inert gas).

The aqueous solution of the alkali salt of bisphenol thus obtained exhibits a particularly low color index. This, of course, also depends on the color index of the bisphenol used. With a bisphenol with a color index of less than 10 Hazen (measured according to ASTM D1686), a color index of less than 1.5 Hazen, preferably less than 1.0, can be achieved.

Polycarbonates may be branched in a purposeful and controlled manner by the use of small amounts of branching agents. Examples of suitable branching agents are: Phloroglucinol, 4,6-dimethyl-2,4,6-tri- (4-hydroxyphenyl) -2
-Heptene, 4,6-dimethyl-2,4,6-tri- (4-hydroxyphenyl) heptane, 1,3,5
-Tri- (4-hydroxyphenyl) benzene, 1,1,1-tri- (4-hydroxyphenyl)
Ethane, tri- (4-hydroxyphenyl) phenylmethane, 2,2-bis- [4,4-bis (4-
Hydroxyphenyl) cyclohexyl] propane, 2,4-bis (4-hydroxyphenylisopropyl) phenol, 2,6-bis (2-hydroxy-5'-methylbenzyl) -4-methylphenol, 2- (4-hydroxyphenyl) ) -2- (2,4-Dihydroxyphenyl) propane, hexa- (4- (4-hydroxyphenylisopropyl) phenyl) ortho-terephthalic acid ester, tetra- (4-hydroxyphenyl) methane, tetra- (4- ( 4-hydroxyphenylisopropyl) phenoxy) methane), α, α ', α''-tris- (4-
(Hydroxyphenyl) -1,3,5-triisopropylbenzene, 2,4-dihydroxybenzoic acid, trimesic acid, cyanuric acid chloride, 3,3-bis (3-methyl-4-hydroxyphenyl) -2-oxo-2 , 3-Dihydroindole, 1,4-bis (4 ', 4''-dihydroxytriphenyl) methyl) benzene. 1,1,1-Tri- (4-hydroxyphenyl) ethane and bis- (3-methyl-4-hydroxyphenyl) -2-oxo-2,3-dihydroindole (ie isatin biscresol).

A branching agent or a mixture of branching agents may optionally be used, preferably introduced together with bisphenol in an amount of from 0.05 to 2 mol% based on the bisphenol used, or more It may be added at a later synthetic stage.

A chain terminator may be used in the present invention. The chain terminator used in the present invention is preferably phenol, for example, phenol, an alkylphenol such as cresol or 4-tert-butylphenol, chlorophenol, bromophenol, cumylphenol, or a mixture thereof. Particularly preferred is phenol, 4-tert-butylphenol or cumylphenol.

The chain terminator and branching agent may be added to the reaction mixture as separate solutions,
Alternatively it may be added together with the bisphenolate. At this time, care must be taken to ensure that the solution has as low an oxygen content as the aqueous solution of the alkaline salt of bisphenol.

Other additives that can be used in the present invention and that can be added to the polycarbonates that make the sheets of the present invention are disclosed in EP-A-0500496 and WO 96/15102. ing. According to the invention, the mixture of said additives may be incorporated into the polycarbonate.

Particularly preferred additives are UV absorbers, eg WO 99/052.
A compound represented by the following formula (I) and a compound represented by the formula (II) described in JP-A No. 05-2005.

[Chemical 1] Wherein, ^{R 1} and ^{R 2} are the same or different, H, _halogen, C 1 _{-C 10 alkyl,} C 5 _{-C 10 cycloalkyl,} C 7 _{-C 13 aralkyl,} C 6 _{-C 1 4} aryl, - OR ⁵ -or- (CO) -O-R ⁵ (wherein R ⁵ is H or C ₁
To C ₄ alkyl), R ³ and R ⁴ are also the same or different,
H, C ₁ -C ₄ alkyl, C ₆ cycloalkyl, benzyl or C ₆ -C ₁₄ aryl, m is 1, 2 or 3, and n is 1, 2, 3 or 4.

[Chemical 2] In the above formula, the bridge is

[Chemical 3] Means R¹, R^Two, M and n have the same meanings as described for formula (I).
Further, p is an integer of 0 to 3, q is an integer of 1 to 10, and Y is —CH.
_Two-CH_Two-,-(CH_Two)_Three-,-(CH_Two)_Four-,-(CH_Two)₅-,-(CH_Two)₆-,Also
Is CH (CH_Three) -CH_Two-And R^Three, R^FourIs described with respect to formula (I)
Has the same meaning as.

Other suitable UV absorbers are substituted triazines, such as 2,4-bis (2,4-dimethylphenyl) -6- (2-hydroxy-4-n-octyloxyphenyl) -1,3 , 5-triazine (
CYASORNB include ^(R) UV-1164) or 2- (4,6-diphenyl-1,3,5-triazin-2-yl) -5- (hexyl) oxyphenol (Tinuvin ^(R) 1577) It is a thing. A particularly preferred UV absorber is 2,2-methylenebis (4- (1,1,3,3-
Tetramethylbutyl) -6- (2H-benzotriazol-2-yl) phenol),
Which is commercially available under the trade name Tinuvin ^(R) 360 or Adeka Stab ^{(registered trademark)} LA31. UV absorber made of BASF AG and which can be produced according to Example 1 of WO 96/15102.
Uvinul 3030 is also suitable, as is the UV absorber described in EP 0 0500496 A1.

Other UV absorbers include 5′-methyl-, 3 ′, 5′-di-tert-butyl-, 5′-tert-butyl-, 5 ′-(1,1,3,3- Tetramethylbutyl)-(ie Tinuvin329), 5-chloro-
3 ', 5'-di-tert-butyl-, 5-chloro-3'-tert-butyl-5'-methyl, 3'-sec-butyl-
5'-tert-butyl-, 4'-octoxy-, 3 ', 5'-di-tert-amyl-, and 3', 5'-bis
(α, α-Dimethylbenzyl) -2H-benzotriazole (2), and 5-chloro-3'-ter
t-Butyl-5 '-(2-octyloxycarbonylethyl) -2H-benzotriazole (2)
And 5-chloro-3'-tert-butyl-5 '-[2- (2-ethylhexyloxy) carbonylethyl
]-, 5-Chloro-3'-tert-butyl-5 '-(2-methoxycarbonylethyl)-, 3'-tert-butyl-5'-(2-methoxycarbonylethyl)-, 3'-tert- Butyl-5 '-(2-octyloxycarbonylethyl)-, 3'-tert-butyl-5'-[2- (2-ethylhexyloxy) -carbonylethyl]-, 3'-dodecyl-5'-methyl -, And a mixture with 3'-tert-butyl-5 '-(2-isooctyloxycarbonylethyl) -2'-hydroxyphenyl-2H-benzotriazole (2), 2,2'-methylenebis [4- ( 1,1,3,3-Tetramethylbutyl) -6-benzotriazol-2-yl-phenol] and 3'-sec-butyl-5 '-(1,1,3,3-tetramethylbutyl- 2'-hydroxyphenyl-2H-benzotriazole (ie Ti
nuvin350), and 2- [2'-hydroxy-3 ', 5'-bis (1,1-dimethylbenzyl) phenyl] -2H-benzotriazole (ie Tinuvin234), and 4-hydroxy-,
4-methoxy-, 4-octoxy-, 4-decyloxy-, 4--dodecyloxy-, 4-benzyloxy-, 4,2 ', 4-trihydroxy, 2'-hydroxy-4,4'-dimethoxy derivative , Ethyl-2-cyano-3,3-diphenyl acrylate (ie Uvinul3035) from BSF Actien Gezelshaft, 2-ethylhexyl-2-cyano-3,3-diphenylacrylate (Uv
2-hydroxybenzophenone such as inul3039).

Examples of suitable stabilizers that can be used as additives in the present invention include phosphine (p
hosphines), phosphites or Si-containing stabilizers, and other compounds described in EP-A-0500496. Triphenylphosphite, diphenylalkylphosphite, phenyldialkylphosphite, tris (nonylphenyl) phosphite, triphenylphosphine, tetrakis (2,4-di-tert-butylphenyl) -4,4'-biphenylenediphosphonite (tetraki
s- (2,4-di-tert.-butylphenyl) -4,4'-biphenylene diphosphonite) and tri-
Aryl phosphites are mentioned as an example. Triphenylphosphine and tris (2,4-di-tert-butylphenyl) phosphite are particularly preferred.

Polycarbonate as a raw material for producing the sheet of the present invention is an additive for improving surface slip characteristics, for example, pentaerythritol tetrastearate / -palmitate, glycerol monostearate / -palmitate. The ester may further contain an ester of a polyhydric alcohol such as glycerol tristearate / -palmitate and a long chain fatty acid. In addition, flame retardants, pigments, colorants, fine minerals, optical brighteners and other additives can be added.

All feeds and solvents used in the synthesis may be contaminated from their manufacturing and storage stages, but the goal is to work with the cleanest starting materials possible.

The transparent glazing of the present invention particularly includes transparent glazing for automobiles or buildings, for example, greenhouses, winter gardens, bus shelters, advertising panels, signboards, protective screens, automobiles. Examples include transparent glazing for window glass, or for windows or roofs.

It is also possible to subsequently process the sheet according to the invention. Subsequent processing includes, for example, thermoforming or surface modification including the application of scratch lacquers, water dispersion layers and the like.

Examples In the following examples, the color index was determined according to ASTM D1686 by measuring the absorption up to 400 nm over an irradiation length of 50 cm.

The weather resistance test of the sheet (according to ISO 4892-2A) is conducted by Atlas of the United States.
A weathering tester manufactured by the same company was used, and a cycle including a 6.5 W xenon lamp for an exposure time of 102 minutes and spraying deionized water for 18 minutes while exposing was performed. The maximum black body temperature was 60 ° C (± 5 ° C). After 1000 hours, the sheet samples were removed and tested for toughness under practical conditions using the modified version of the dart test developed for multiple sheets according to DIN 53 443. The breaking energy W _s , measured using a 5 mm diameter fractured body, was intended to produce a biaxial stress equivalent to that produced by the falling hail grains. At room temperature, a 36 kg falling mass falling from a height of 0.2 m was applied to the sample. The sample was left unfixed on a support ring having an inner diameter of 20 mm.

In the compression region, the surface of the sample that was weather tested was tested. The appearance (BB) of the fracture surface was evaluated by the following numerical values. 1 is broken into pieces, 2 is an uneven crack, 3 is ductile / brittle, and 4 is ductile.

The yellowness index determined according to ASTM E313 was expressed as yellowness index Y1.

Example 1 To produce 1.022 t / h of a 15% NaBPA aqueous solution, 867.
5 kg of 6.5% aqueous sodium hydroxide solution and 154.5 kg / h of bisphenol A melt were combined continuously. All processes were performed under an inert nitrogen atmosphere. The 6.5% aqueous sodium hydroxide solution had an oxygen content of 10 ppb. The Hazen color index of the resulting 15% aqueous sodium bisphenolate solution reached 0.5 Hazen. Using this sodium bisphenolate solution, a polycarbonate was produced by an interfacial polycondensation method.

Comparative Example 2 In order to produce 1.022 t / h of a 15% aqueous sodium bisphenolate solution, 867.5 kg / h of a 6.5% aqueous sodium hydroxide solution and 154.
5 kg of bisphenol A melt were combined continuously. All processes were performed under an inert nitrogen atmosphere. A 6.5% sodium hydroxide aqueous solution has an oxygen content of 250.
It was ppb. Haze of the obtained 15% sodium bisphenolate aqueous solution
The n-color index reached 2 Hazen. Using this sodium bisphenolate solution, a polycarbonate was produced by an interfacial polycondensation method.

Example 3 Melt flow index (MFR) 3 (IS
O 1133 which was measured according to), branching agent content 0.3 mole% isatin biscresol and UV absorber content 0.25% Tinuvin ^(R) 350 (3'-sec-
A polycarbonate with butyl-5 ′-(1,1,3,3-tetramethylbutyl-2′-hydroxyphenyl-2H-benzotriazole) was produced from the sodium bisphenolate solution obtained in Example 1. This polycarbonate was processed in the following plant to produce a 10 mm coextruded double sheet. A main extruder with a screw with a length of 33 D and a diameter of 70 mm with outlet, a coextruder with a screw of a length of 25 D and a diameter of 30 mm for applying the outer layer, a special with a width of 350 mm Sheet dies, -calibrators, -roller conveyors, -removal units, -cutting devices (saws), -stacking stands.

The polycarbonate obtained from Example 1 was fed and introduced into a coextruder.
Such co-extrusion is known in the prior art (see, for example, European Patent Application Publication Nos. A110221 and A110238). In this example, the following process was performed. The extruder for producing the core layer and the outer layer was connected to the adapter of the coextruder. The adapter was designed so that the melt forming the outer layer was applied as a thin film that adhered to the core layer melt. The multilayer melt strand thus produced was then formed into the desired shape (double sheet) with a die connected downstream. The melt was then cooled in a known manner under controlled conditions using a vacuum scale and then sawed into 1 meter long pieces.

Comparative Example 4 Melt Flow Index (MFR) 3 (IS
O 1133 which was measured according to), branching agent content 0.3 mole% isatin biscresol and UV absorber content 0.25% Tinuvin ^(R) 350 (3'-sec-
A polycarbonate with butyl-5 '-(1,1,3,3-tetramethylbutyl-2'-hydroxyphenyl-2H-benzotriazole) was produced from the sodium bisphenolate solution obtained in Example 2. This polycarbonate was processed in the same plant as in Example 3 under the same conditions to produce a 10 mm coextruded double sheet.

Example 5 Phenol end groups and melt flow index (MFR) 3 (ISO 11
(According to 33) was produced from the sodium bisphenolate solution obtained in Example 1. This polycarbonate was processed in the same plant as in Example 3 under the same conditions to produce a 10 mm coextruded double sheet.

The polycarbonate obtained from Example 1, 5% benzotriazole UV absorber (Tinuvin ^(R) 360, which is 2,2-methylene bis - (4- (1,1,3,3-tetramethyl Butyl) -6- (2H-benzotriazol-2-yl) phenol) was introduced into the co-extruder, which compound was prepared by the following method: UV
Absorbent is a twin screw extruder (Wener & Pfleder
The mixture was mixed with the polycarbonate in a ZSK 32) from iderer) at 280 ° C. and 80 revolutions / minute, after which the extrudate was pelletized.

Comparative Example 6 A polycarbonate having phenol end groups and a melt flow index (MFR) 3 (according to ISO 1133) was produced from the sodium bisphenolate solution obtained in Example 2. This polycarbonate was processed in the same plant as in Example 3 under the same conditions to produce a 10 mm coextruded double sheet.

The polycarbonate obtained from Example 1, 5% benzotriazole UV absorber (Tinuvin ^(R) 360, which is 2,2-methylene bis - (4- (1,1,3,3-tetramethyl Butyl) -6- (2H-benzotriazol-2-yl) phenol) was introduced into the co-extruder, which compound was prepared by the following method: UV
Double-shaft type extruder (Wener & Flyderer)
PSK was mixed in a Pfleiderer) ZSK 32) at 280 ° C. and 80 revolutions / minute and then the extrudate was pelletized.

Comparative Example 7 Melt flow index (MFR) 3 (IS
O 1133 those were measured in accordance with) and UV absorber content 0.3% Tinuvin ^{(registered trademark)} 350 (3'-sec-butyl-5 '- (1,1,3,3-tetramethylbutyl Polycarbonate with -2'-hydroxyphenyl-2H-benzotriazole) was produced from the sodium bisphenolate solution obtained in Example 1. This polycarbonate was processed by injection molding to give 3 mm thick color chips. Manufactured.

Comparative Example 8 Melt Flow Index (MFR) 3 (IS
O 1133 those were measured in accordance with) and UV absorber content 0.3% Tinuvin ^{(registered trademark)} 350 (3'-sec-butyl-5 '- (1,1,3,3-tetramethylbutyl Polycarbonate with -2'-hydroxyphenyl-2H-benzotriazole) was produced from the sodium bisphenolate solution obtained in Example 2. This polycarbonate was processed by injection molding to give color chips with a thickness of 3 mm. Manufactured.

The obtained sheet was then subjected to colorimetric evaluation using the following measuring method. 1. Transmittance (based on standard ASTM D1003) Device: Pye-Unicam (for measurement of bonded structures: 0 ° / diffusion, calculated according to illuminant C) 1. Yellowness index Y1 according to ASTM E313 3. According to ISO 4892-2A, a weather resistance test of the sheet is carried out in a weather resistance tester manufactured by Atlas, USA using a 6.5 W xenon lamp for an exposure time of 102 minutes, and spraying deionized water for 18 minutes while exposing. It was carried out in a cycle including the above.
The maximum black body temperature was 60 ° C (± 5 ° C). After 1000 hours, the sheet samples were removed and tested for toughness under practical conditions using the modified version of the dart test developed for multiple sheets according to DIN 53 443. The breaking energy W _s , measured using a 5 mm diameter fractured body, was intended to produce a biaxial stress equivalent to that produced by the falling hail grains. At room temperature, a 36 kg falling mass falling from a height of 0.2 m is applied to the sample. The sample was left unfixed on a support ring having an inner diameter of 20 mm.

In the compression region, the surface of the sample that was weather tested was tested. The appearance (BB) of the fracture surface was evaluated by the following numerical values. 1 is broken into pieces, 2 is an uneven crack, 3 is ductile / brittle, and 4 is ductile.

The yellowness index determined according to ASTM E313 was expressed as yellowness index Y1.

[0055] result:

[Table 1]

[0056]

[Table 2]

The above results show that the sheets produced according to the present invention have higher transmission, lower yellowness index and better mechanical stability than the sheets according to the comparative test. ing.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) B29L 7:00 B29L 7:00 C08L 69:00 C08L 69:00 (81) Designated country EP (AT, BE, CH, CY, DE, DK, ES, FI, FR, GB, GR, IE, IT, LU, MC, NL, PT, SE), OA (BF, BJ, CF, CG, CI, CM, GA, GN, GW, ML, MR, NE, SN, TD, TG), AP (GH, GM, KE, LS, MW, MZ, SD, SL, SZ, TZ, UG, ZW), EA (AM, AZ , BY, KG, KZ, MD, RU, TJ, TM), AE, AG, AL, AM, AT, AU, AZ, BA, BB, BG, BR, BY, BZ, CA, C H, CN, CR, CU, CZ, DE, DK, DM, DZ, EE, ES, FI, GB, GD, GE, GH, GM, HR, HU, ID, IL, IN, IS, JP, KE , KG, KP, KR, KZ, LC, LK, LR, LS, LT, LU, LV, MA, MD, MG, MK, MN, MW, MX, MZ, NO, NZ, PL, PT, RO, R U, SD, SE, SG, SI, SK, SL, TJ, TM, TR, TT, TZ, UA, UG, US, UZ, VN, YU, ZA, ZW (72) Inventor Wolfgang Nizing Federal Republic of Germany De-53757 St. Augustin, Mainstraße No. 4 (72) inventor Jürgen Lehner, Federal Republic of Germany De-51069 Cologne, Brambachstraße No. 86 (72) Inventor Stefen Curing, Federal Republic of Germany --40670 Meerbusch, Gocher-Week No. 5 (72) Inventor Rolf Lanze De Fayde Germany-47804 Krefeld, Aldekerker Strasse No. 42 (72) Inventor Michael Plein Belgium, Beh-2930 Brasshart, Oude Hoofewegh 9th (72) Inventor Reiner Neumann Germany Day – 47803 Krefeld, Kleedbruchstraße 92th (72) Inventor Hermann Kaut Germany Day – 47803 Krefeld, Satler Dük 6th (72) Inventor Frieder Hadenreich Day of Germany-40593 Düsseldorf, Haydnstraße No. 20 (72) Inventor Tony van Osseler, Republic of Germany Day of 47800 Krefeld, Sebastian Strasse No. 14F Term (reference) ) 4F071 AA50 AF03 AF30 AH0 1 AH03 AH07 AH11 BB06 BC02 BC03 4F100 AG00 AK45A AT00B BA02 EH17 EH172 GB07 GB32 GB90 JN01 4F207 AA28 AG01 AG03 AH17 AH48 KA01 KA17 KB26 4J029 AA09 AB01 AC01 AE01 BB11A BB12A01 BB13A FA07

Claims (8)

[Claims] 1. A polycarbonate is produced by an interfacial polycondensation method, and an aqueous solution of an alkali salt of bisphenol used therefor has a dissolved oxygen content of 150 p.
A polycarbonate sheet having pb or less. 2. Use of the polycarbonate sheet according to claim 1 for producing transparent glazing. 3. A transparent glass sheet containing the polycarbonate sheet according to claim 1. 4. An automobile, a building, a greenhouse, a winter garden, a bus shelter, an advertising panel, which comprises the polycarbonate sheet according to claim 1.
Clear glazing for signs, protective screens, or windows or roofs. 5. A multi-layer sheet, at least one layer of which contains the polycarbonate sheet of claim 1. 6. The method for producing a polycarbonate sheet according to claim 1, which is produced by extrusion molding. 7. The method for producing a multiple sheet according to claim 5, which is produced by coextrusion molding. 8. The multiplex sheet according to claim 5, wherein at least one layer contains a UV absorber and the concentration of the UV absorber in the layer is preferably 0.01 to 20% by weight.