CA2233988A1 - Amorphous moulding from a polyethylene terephthalate plate - Google Patents
Amorphous moulding from a polyethylene terephthalate plate Download PDFInfo
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- CA2233988A1 CA2233988A1 CA002233988A CA2233988A CA2233988A1 CA 2233988 A1 CA2233988 A1 CA 2233988A1 CA 002233988 A CA002233988 A CA 002233988A CA 2233988 A CA2233988 A CA 2233988A CA 2233988 A1 CA2233988 A1 CA 2233988A1
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- molding
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Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C51/00—Shaping by thermoforming, i.e. shaping sheets or sheet like preforms after heating, e.g. shaping sheets in matched moulds or by deep-drawing; Apparatus therefor
- B29C51/002—Shaping by thermoforming, i.e. shaping sheets or sheet like preforms after heating, e.g. shaping sheets in matched moulds or by deep-drawing; Apparatus therefor characterised by the choice of material
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C51/00—Shaping by thermoforming, i.e. shaping sheets or sheet like preforms after heating, e.g. shaping sheets in matched moulds or by deep-drawing; Apparatus therefor
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C35/00—Heating, cooling or curing, e.g. crosslinking or vulcanising; Apparatus therefor
- B29C35/02—Heating or curing, e.g. crosslinking or vulcanizing during moulding, e.g. in a mould
- B29C35/08—Heating or curing, e.g. crosslinking or vulcanizing during moulding, e.g. in a mould by wave energy or particle radiation
- B29C35/0805—Heating or curing, e.g. crosslinking or vulcanizing during moulding, e.g. in a mould by wave energy or particle radiation using electromagnetic radiation
- B29C2035/0822—Heating or curing, e.g. crosslinking or vulcanizing during moulding, e.g. in a mould by wave energy or particle radiation using electromagnetic radiation using IR radiation
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C35/00—Heating, cooling or curing, e.g. crosslinking or vulcanising; Apparatus therefor
- B29C35/16—Cooling
- B29C2035/1616—Cooling using liquids
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C35/00—Heating, cooling or curing, e.g. crosslinking or vulcanising; Apparatus therefor
- B29C35/16—Cooling
- B29C2035/1658—Cooling using gas
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C35/00—Heating, cooling or curing, e.g. crosslinking or vulcanising; Apparatus therefor
- B29C35/02—Heating or curing, e.g. crosslinking or vulcanizing during moulding, e.g. in a mould
- B29C35/04—Heating or curing, e.g. crosslinking or vulcanizing during moulding, e.g. in a mould using liquids, gas or steam
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29K—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
- B29K2067/00—Use of polyesters or derivatives thereof, as moulding material
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Blow-Moulding Or Thermoforming Of Plastics Or The Like (AREA)
- Manufacture Of Macromolecular Shaped Articles (AREA)
- Compositions Of Macromolecular Compounds (AREA)
- Processing And Handling Of Plastics And Other Materials For Molding In General (AREA)
- Testing Resistance To Weather, Investigating Materials By Mechanical Methods (AREA)
- Treatments Of Macromolecular Shaped Articles (AREA)
Abstract
The present invention relates to an amorphous, thermoformed moulding, with a thickness in the range of from 1 to 20 mm, which as the main component contains a crystallisable polyethylene terephthalate and is characterised by good mechanical and good optical properties. The moulding can optionally be transparent, dyed to be translucent or dyed to be opaque. In a preferred embodiment, it is also UV-stabilised. The invention also relates to a method for the production of said moulding, and use thereof.
Description
-WO 97/12750FILE, 1~ THI~AMENDE!:? PCT/EP96/04207 lE~T TRANSLATI~:)N
Description Amorphous molding made from a polyethylene terephthalate sheet 5 The invention relates to a process for the production of amorphous moldings from amorphous polyethylene terephthalate sheets, and to the amorphous moldings themselves. The moldings can either be transparent, transparently colored or opaquely colored. The moldings have good mechanical properties in addition to good optical properties.
Amorphous, transparent sheets having a thickness of from 1 to 20 mm are well known. These two-dimensional structures comprise amorphous, non-crystallizable thermoplastics. Typical examples of such thermoplastics which can be converted into sheets are, for example, polyvinyl chloride 15 (PVC), polycarbonate (PC) and polymethyl methacrylate (PMMA). These semifinished products are produced on so-called extrusion lines (cf.
PolymerWerkstoffe, Volume ll, Technologie 1, p. 136, Georg Thieme Verlag, Stuttgart, 1984). The pulverulent or granular raw material is melted in an extruder. After extrusion, the amorphous thermoplastics can easily be 20 shaped via polishing stacks or other shaping tools as a consequence of their viscosity, which continuously increases with decreasing temperature.
After shaping, amorphous thermoplastics then have adequate stability, i.e.
a high viscosity, in order to be self-supporting in the calibration die.
However, they are still sufficiently soft to be shaped by the die. The melt 25 viscosity and inherent rigidity of amorphous thermoplastics are so high in the calibration die that the semifinished product does not collapse in the calibration die before cooling. In the case of easily decomposed materials, for example PVC, special processing aids, for example processing stabilizers against decomposition and lubricants against excessive internal 30 friction and thus uncontrollable warming, are necessary during extrusion.
External lubricants are necessary to prevent sticking to walls and rolls.
The processing of PMMA is carried out using, for example, a vented extruder to enable removal of moisture.
-The production of transparent sheets from amorphous thermoplastics sometimes requires expensive additives, which can migrate and can cause production problems owing to evaporation and surface coatings on the semifinished product. PVC sheets can be recycled only with difficulty or 5 using special neutralization or electrolysis processes. PC and PMMA
sheets can likewise only be recycled with difficulty and only with loss or extreme impairment of the mechanical properties.
In addition to these disadvantages, PMMA sheets also have extremely 10 poor impact strength and splinter on fracture or mechanical loading.
Furthermore, PMMA sheets are readily combustible, which means that they cannot be employed, for example, for internal applications and in exhibitions.
15 PMMA and PC sheets furthermore cannot be shaped when cold; PMMA
sheets disintegrate to form dangerous splinters, while PC sheets undergo hairline cracking and stress whitening.
PMMA and PC sheets absorb moisture. The moisture content increases during production, transport and storage. Although the performance of the extruded sheet is not impaired, the increased moisture causes bubbles and other surface defects and impairment of the properties during shaping (thermoforming and vacuum forming). Before mechanical shaping, these sheets must be dried for between 1 hour and 48 hours, depending on the sheet thickness, at temperatures above 120~C in a fan-assisted oven (cf.
Technicai Handbook GE Plastics Structured Products, Solid Lexan sheets), which is energy- and time-consuming.
German Patent Application 195221 18.4 (prior art as defined in 3 ll 30 PatG) describes an amorphous, transparent sheet having a thickness in the range from 1 to 20 mm whose principal constituent is a crystallizable thermoplastic and which contains at least one UV light stabilizer. In addition to high UV stability, the sheet is distinguished both by good optical properties, for example high light transmission, high surface gloss, low haze and high clarity, and by good mechanical properties, for example high impact strength and high breaking strength.
German Patent Application 195 22 120.6 (prior art as defined in 3 ll PatG) describes an amorphous, transparently colored, UV-stabilized sheet made from a crystallizable thermoplastic whose thickness is in the range from 1 to 20 mm. The sheet contains at least one UV light stabilizer and at least one polymer-soluble dye. In addition to high UV stability, the sheet is distinguished by good optical and mechanical properties.
German Patent Application 195 22 119.2 (prior art as defined in 3 ll PatG) describes an amorphous, colored, UV-stabilized sheet made from a crystallizable thermoplastic whose thickness is in the range from 1 to 20 mm. The sheet contains at least one UV light stabilizer and at least one organic and/or inorganic pigment as colorant. In addition to high UV
stability, the sheet is distinguished by homogeneous optical properties and good mechanical properties.
EP-A-0 471 528 describes a process for shaping an article made from a polyethylene terephthalate (PET) sheet. The PET sheet is heat-treated on both sides in a thermoforming mold in a temperature range between the glass transition temperature and the melting point. The shaped PET sheet is removed from the mold when the degree of crystallization of the shaped PET sheet is in the range from 25 to 50 %. The PET sheets disclosed in EP-A-0 471 528 have a thickness of from 1 to 10 mm. Since the thermoformed moldings produced from this PET sheet have high crystallization, there is no possibility of obtaining a transparent article. Themolding is always opaque to light. In addition, the thermoformed molding has poor mechanical properties, in particular poor impact strength, owing to the crystallization.
US-A-3,496,143 describes the vacuum forming of a PET sheet with a thickness of 3 mm whose crystallization is in the range from 5 to 25 %.
However, the crystallinity of the vacuum-formed molding is greater than 25 %. Since the sheet described and the molding vacuum-formed therefrom are partially crystalline, there is again no possibility here of obtaining a transparent article or a transparent sheet. In addition, both the sheet and the molding vacuum-formed therefrom have poor mechanical 5 properties, in particuiar poor impact strength, owing to the crystallization.
Processes for the production of transparent or clear moldings from amorphous or partially crystalline PET sheets having a thickness of up to 6 mm by vacuum forming are also described in Austrian Patent Specification Nos. 304 086 and 285 160.
However, the PET employed in Austrian Patent No. 304 086 is glycol-modified PET (PET-G), i.e. a copolymer comprising ether and ester units.
PET-G is naturally amorphous and can only be crystallized with difficulty. In addition, the PET employed here has a crystallization temperature -15 corresponding to the post- (cold) crystallization temperature TCN- of at least 160~C.
Austrian Patent No. 285 160 uses a PET sheet having a thickness of 3 mm and a degree of crystallization of 21 %. The molding obtained therefrom was consequently at least partially crystalline and thus no longer 20 transparent.
The object of the present invention was therefore to provide thermoformed moldings which are either transparent, colored in a transparent manner or colored in an opaque manner and have a thickness in the range from 1 to 25 20 mm with optical and mechanical properties which essentially correspond to those of amorphous polyethylene terephthalate sheets.
The good mechanical properties include, in particular, high impact strength and high breaking strength.
The good optical properties of the transparent or transparently coloredembodiment include, for example, high light transmission and a homogeneous appearance.
In addition, the novel molding should be recyclable, economic to produce and have low flammability so that it can also be used, for example, for indoor applications.
5 In a particular embodiment, the molding is also UV-resistant so that it is suitable for outdoor applications.
This object is achieved by a process for the production of an amorphous molding which comprises warming, thermoforming, cooling and 10 subsequently demolding an amorphous sheet having a thickness in the range from 1 to 20 mm, preferably in the range from 1 to 10 mm, whose principal constituent is crystallizable polyethylene terephthalate.
Amorphous sheets having a thickness in the range from 1 to 20 mm whose 15 principal constituent is crystallizable polyethylene terephthalate and which are suitable as starting materials for the novel process, and their production, are disclosed, for example, in German Patent Applications 195 19 579.5,195 19 578.7,195 19 577.9, 195 22 118.4,195 22 120.6, 195 22 119.2, 195 28 336.8,195 28 334.1 and 195 28 333.3.
For the purposes of the present invention, the term crystallizable polyethylene terephthalate is taken to mean - crystallizable polyethylene terephthalate homopolymers, - crystallizable polyethylene terephthalate copolymers, 25 - crystallizable polyethylene terephthalate compounds, - crystallizable polyethylene terephthalate recyclate and - other variants of crystallizable polyethylene terephthalate.
Preferred starting materials for the production of the amorphous sheet are 30 polyethylene terephthalate polymers having a post- (cold) crystallization temperature TCN in the range from 120 to 158~C, in particular from 130 to 158~C.
For the purposes of the present invention, amorphous sheets are taken to -mean those which are non-crystalline, although the crystallizable thermoplastic employed preferably has a crystallinity of from 25 to 65 %.
Non-crystalline, i.e. essentially amorphous, means that the degree of crystallinity is generally less than 5 %, preferably less than 2 %, particularly5 preferably 0 %.
In contrast to sheets made from conventional materials, for example polymethyl methacrylate (PMMA) and polycarbonate (PC), sheets whose principal constituent is crystallizable polyethylene terephthalate generally 10 do not need to be dried before thermoforming, but instead can be processed directly without the usual preparatory steps for processing.
The warming or heating of the sheet can be effected using any heating device known to the person skilled in the art for thermoforming. The sheet 15 is preferably heated using a hot-air oven or an infra-red radiator.
In order to achieve extremely quick and uniform heating of the sheet, the latter is preferably heated on both sides, i.e. with top and bottom heat.
20 The sheet is preferably heated until the sheet temperature is in the range from 120~ to 160~C, preferably in the range from 130~ to 145~C.
If large-area sheets are used, sagging of the sheets during heating can occur. In this case, the sheets are preferably supported by means of 25 compressed air during the heating.
Typical heating times for transparent sheets whose principal constituent is polyethylene terephthalate are, for example, about 1/3 of the time necessary for PMMA and PC sheets.
Differences can occur depending on the nature and efficiency of the available heating. Colored sheets may have additional time differences owing to the different heat absorption behavior.
Warming is followed by shaping, also referred to as thermoforming. The heated sheets employed can be thermoformed by standard methods, like other materials.
5 In order to ensure uniform thickness distribution over the entire material during the thermoforming process, the usual methods can be used, for example variation of the temperature profile of the sheets, specific vacuum settings or blowing up a dome as precursor to shaping.
10 In addition, it is advantageous for the production of an amorphous molding for the temperature of the mold to be kept below 80~C, preferably below 60~C.
Furthermore, the time between the end of the heating period and the 15 completion of the shaping operation should be kept short. A mold design having a maximum number of vent holes and the maximum diameter (for example 1 mm) is therefore preferably recommended.
After completion of the shaping operation, the molding should be cooled 20 rapidly using air or air/spray water.
The subsequent demolding is preferably not carried out until the molding is at a temperature below 60~C.
25 Owing to the low and uniform shrinkage, which is preferably < 1.0 %, the molding produced can easily be removed from the mold. Subsequent shrinkage of the molding with time does not occur. The molding remains dimensionally stable.
30 The invention furthermore relates to an amorphous, thermoformed molding having a thickness in the range from 1 to 20 mm whose principal constituent is a crystallizable polyethylene terephthalate and whose surface gloss, measured in accordance with DIN 67530 (measurement angle 20~), is greater than 90, preferably greater than 100.
~ CA 02233988 1998-04-03 For the purposes of the present invention, the term amorphous molding is taken to mean a molding whose crystallinity is generally less than 5 %, preferably less than 2 %, particularly preferably 0 %.
5 The novel moldings preferably do not break during measurement of the Charpy impact strength an (measured in accordance with ISO 179/1 D).
In addition, the Izod notched impact strength ak (measured in accordance with ISO 180/1A) of the moldings is preferably in the range from 3.0 to 10 8.0 kJ/m2, particularly preferably in the range from 4.0 to 6.0 kJ/m2.
The amorphous, thermoformed molding can be either transparent, colored in a transparent manner or colored in an opaque manner.
15 In the transparent embodiment, the novel thermoformed molding has a light transmission, measured in accordance with ASTM D 1003, of greater than 80 %, preferably greater than 84 %.
The haze of the molding, measured in accordance with ASTM D 1003, is 20 less than 15 %, preferably less than 11 % and the clarity of the molding, determined at an angle of less than 2.5~ (ASTM D 1003), is preferably greater than 94 %, particularly preferably greater than 96 %.
In the transparently colored embodiment, where the molding contains at 25 least one dye which is soluble in the polyethylene terephthalate, preferably in a concentration of from 0.001 to 20 % by weight, based on the weight of the crystallizable polyethylene terephthalate, the light transmission, measured in accordance with ASTM D 1003, is in the range from 5 to 80 %, preferably in the range from 10 to 70 %.
The haze of the molding, measured in accordance with ASTM D 1003, is in the range from 2 to 40 %, preferably in the range from 3 to 35 %, and the clarity of the molding, determined at an angle of less than 2.5~ (ASTM
D 1003), is preferably greater than 90 %, particularly preferably greater than 92 %.
In the opaquely colored embodiment, where the molding contains at least one organic and/or inorganic pigment as colorant and, if desired, 5 additionally a soluble dye, where the concentration of the pigment is preferably in the range from 0.5 to 30 % by weight, based on the weight of the crystallizable polyethylene terephthalate, the light transmission, measured in accordance with ASTM D 1003, is less than 5 %.
10 Suitable soluble dyes are disclosed, for example, in German Patent Application 195 19 578.7, and suitable organic and/or inorganic pigments as colorants are disclosed, for example, in German Patent Application 195 19 577.9.
15 In a preferred embodiment, the amorphous, thermoformed molding contains at least one UV light stabilizer, where the concentration of the UV
stabilizer is preferably in the range of 0.01 to 5 % by weight, based on the weight of the crystallizable polyethylene terephthalate.
20 Suitable UV light stabilizers are disclosed, for example, in German Patent Applications 195 22 118.4,195 22 120.6 and 195 22 119.2.
Measurements have furthermore shown that the novel molding has low combustibility and low flammability, so that it is also suitable for indoor 25 applications and in exhibitions.
Furthermore, the novel molding can easily be recycled without environmental pollution and without impairment of the mechanical properties, which means that it is suitable, for example, for use as 30 temporary advertising signs or other advertising articles.
The surprising multiplicity of excellent properties make the novel amorphous molding highly suitable for a multiplicity of different uses, for example for interior room panels, for exhibitions and exhibition articles, for . CA 02233988 1998-04-03 -signs, for protective glazing of machines and vehicles, in shop fitting and shelf construction, as advertising articles, as menu holders, as basketball backboards, as room dividers, for aquaria and as brochure and newspaper holders.
In the UV-stabilized embodiment, the novel amorphous molding is also suitable for outdoor applications, for example for greenhouses, roofing systems, glazing systems, safety glass, external cladding, covers, for applications in the construction sector, illuminated advertising profiles, 10 balcony cladding, roof exits and caravan windows.
In addition, it has been found, surprisingly, that the novel amorphous, thermoformed moldings have good mechanical properties even at low temperatures of down to 40~C without impairment of the optical properties.
15 The good mechanical properties include, inter alia, high breaking strength, high notched jmpact strength, excellent tensile behavior and excellent flexural behavior.
The novel moldings can therefore also advantageously be used in 20 refrigeration systems.
Examples of refrigeration systems or refrigeration equipment are domestic and commercial electric refrigerators and freezers, compressor refrigerators, milk cooling systems, chill cabinets, blood storage refrigerators, mortuary refrigeration systems, medical cooling equipment 25 and laboratory freezers.
The invention is described in greater detail below with reference to working examples without this representing a limitation.
30 The individual properties are measured in accordance with the following standards or by the following processes.
-Measurement methods Surface gloss:
5 The surface gloss is measured in accordance with DIN 67 530. The reflector value is measured as a core optical parameter for the surface of a sheet. In accordance with ASTM-D 523-78 and ISO 2813 standards, the angle of incidence is set at 20~. A light beam hits the planar test surface at the set angle of incidence and is reflected or scattered thereby. The light 10 beams hitting the photoelectric receiver are indicated as proportional electrical quantities. The measurement value is dimensionless and must be given together with the angle of incidence.
Light transmission:
15 The light transmission is taken to mean the ratio between the total amount of transmitted light and the amount of incident light.
The light transmission is measured using a "Hazegard plus" instrument in accordance with ASTM D 1003.
Haze and clarity:
Haze is the percentage of transmitted light deflected from the incident ray bundle by an average of more than 2.5~. The clarity is measured at an angle of less than 2.5~.
The haze and clarity arre measured using a "Hazegard plus" instrument in accordance with ASTM D 1003.
Whiteness The whiteness is determined using an "ELREPHO" electric remission photometer from Zeiss, Oberkochem (DE), standard illuminant C, 2~
standard observer. The whiteness is defined as -W=RY+3RZ-3RX.
(W = whiteness, RY, RZ and RX = corresponding reflection factors when the Y, Z and X color measurement filter respectively is used). White 5 standard is a barium sulfate disk (DIN 5033, Part 9).
Surface defects:
The surface defects are determined visually.
10 Charpy impact strength an:
This parameter is determined in accordance with ISO 179/1 D.
Izod notched impact strength ak:
The Izod notched impact strength ak is measured in accordance with ISO 180/1 A.
Density:
The density is determined in accordance with DIN 53479.
20 SV (DCA) and IV (DCA):
The standard viscosity SV (DCA) is measured in accordance with DIN 53728 in dichloroacetic acid.
The intrinsic viscosity (IV) is calculated as follows from the standard 25 viscosity (SV) IV (DCA) = 6.67 x 10~ SV (DCA) + 0.118.
Thermal properties:
The thermal properties, such as crystalline melting point Tm~ crystallization temperature range Tc, after- or cold-crystallization temperature TCN and glass transition temperature Tg are measured by differential scanning calorimetry (DSC) at a heating rate of 10~C/min.
Molecular weight and polydispersity:
The molecular weights Mw and Mn and the resultant polydispersity MW/Mn are measured by gel permeation chromatography (GPC).
Weathering (on both sides), UV stability:
The UV stability is tested as follows in accordance with ISO 4982 test specification:
Test instrument : Atlas Ci 65 Weather-O-Meter 10 Test conditions : ISO 4892, i.e. artificial weathering Exposure time : 1000 hours (perside) Exposure : 0.5 W/m2, 340 nm Temperature : 63~C
Relative atmospheric 15 humidity : 50 %
Xenon lamp : inner and outer filters made of borosilicate Exposure cycle : 102 minutes UV light, then 18 minutes UV light with water spraying of the samples, then a further 102 minutes of UV light, etc.
The examples and comparative examples below each use single-layer sheets produced on the extrusion line described in the abovementioned German Patent Applications.
Example 1:
An amorphous, transparent sheet made from a crystallizable polyethylene terephthalate whose preparation is described in German Patent Application 195 35 180.0, having the following property profile:
-Thickness : 4 mm - Surface gloss, 1st side : 178 ~ CA 02233988 l998-04-03 (measurement angle 20~) 2nd side : 172 - Lighttransmission : 89.4 %
- Clarity : 99.7 %
-Haze : 2.1%
- Surface defects perm2 : none - Crystallinity : 0 %
- Density : 1.33 g/cm3 - Charpy impact strength an at 23~C : no break - Izod notched impact strength ak at 23~C : 4.7 kJ/m2 is thermoformed on a UA 100 g vacuum thermoforming machine from Illig, Heilbronn, with the following parameters:
- Sheet size : 1000 mm x 700 mm - Sheetthickness : 4 mm - Mold area : 960 mm x 660 mm -Thermoforming depth : 200 mm - Predrying : 0 min (unnecessary) - Mold temperature : 50~C
- Heater output, top heating : 65 %
- Heater output, bottom heating : 45 %
- Preheating with top and bottom heating/
thermoforming : 38 sec - Vacuum : yes - Sheet temperature : 140~C
- Cooling with spray water : 40 sec - Temperature of the shaped article on removal from the mold : 50~C
30 The entire thermoforming cycle therefore takes only 78 seconds.
The shaped article has the following properties:
- Color : transparent - Lighttransmission : 87.8 %
- Haze : 3.4 %
- Surface gloss, 1st side : 150 (measurement angle 20~) 2nd side : 162 - Shrinkage : 0.5 %
- Density : 1.33 g/cm3 -Crystallinity : 0 %
- Charpy impact strength an at 23~C : no break - Izod notched impact strength ak at 23~C : 4.7 kJ/m2 - Charpy impact strength an at 40~C : 78 kJ/m2 - Izod notched impact strength ak at 40~C : 2.4 kJ/m2 Example 2 15 An amorphous, transparent sheet made from a crystallizable polyethylene terephthalate and containing 0.6 % by weight of the UV stabilizer 2,2'-methylenebis(6-(2H-benzotriazol-2-yl)4-(1,1,3,3-tetramethylbutyl)-phenol (~IDTinuvin 360 from Ciba-Geigy), based on the weight of the polymer, is thermoformed analogously to Example 1.
20 The UV-stabilized sheet has the following property profile:
- Thickness : 4 mm - Surface gloss, 1st side : 176 (measurement angle 20~) 2nd side : 174 - Lighttransmission : 89.1 %
- Clarity : 99.5 %
-Haze : 2.3%
- Surface defects per m2 : none - Crystallinity : 0 %
- Density : 1.33 g/cm3 - Charpy impact strength an at 23~C : no break - Izod notched impact strength ak at 23~C : 4.6 kJ/m2 The thermoforming parameters, the temperatures and the thermoforming cycle time are selected analogously to Example 1.
The shaped, UV-stabilized article has the following properties:
- Color : transparent - Lighttransmission : 86.9 %
- Haze : 3.6 %
- Surface gloss, 1st side : 148 (measurement angle 20~) 2nd side : 159 - Shrinkage : 0.5 %
- Density : 1.33 g/cm3 -Crystallinity : o %
- Charpy impact strength an at 23~C : no break - Izod notched impact strength ak at 23~C : 4.5 kJ/m2 - Charpy impact strength an at -40~C : 79 kJ/m2 - Izod notched impact strength ak at -40~C : 2.2 kJ/m2 Example 3:
20 An amorphous sheet colored transparent red, made from a crystallizable polyethylene terephthalate and containing 2 % by weight of the soluble dye Solvent Red 138, an anthraquinone derivative from BASF (~'Thermoplast G), based on the weight of the polymer, is thermoformed analogously to Example 1.
The sheet colored transparent red has the following property profile:
- Thickness : 2 mm - Coloration : red transparent - Surface gloss, 1st side : 130 (measurement angle 20~) 2nd side : 127 - Lighttransmission : 35.8 %
- Clarity : 99.1 %
- Haze : 3.5 %
- Surface defects per m2 : none - Charpy impact strength an at 23~C : no break - Izod notched impact strength ak at 23~C : 4.1 kJ/m2 -Crystallinity : 0 %
- Density : 1.33 g/cm3 The thermoforming parameters and temperatures are selected analogously to Example 1. Owing to the lower sheet thickness, the thermoforming cycle time is only 37 seconds, with 17 seconds required for preheating with top 10 and bottom heat and for the thermoforming operation and 20 seconds required for cooling with spray water.
The shaped article has the following properties:
- Color : red transparent - Light transmission : 34.9 %
-Haze : 3.8%
- Surface gloss, 1 st side : 118 (measurement angle 20~) 2nd side : 126 - Shrinkage : 0.4 %
- Density : 1.33 g/cm3 - Crystallinity : ~ %
- Charpy impact strength an at 23~C : no break - Izod notched impact strength ak at 23~C : 4.0 kJ/m2 - Charpy impact strength an at -40~C : 69 kJ/m2 - Izod notched impact strength ak at -40~C : 2.0 kJ/m2 Example 4:
30 An amorphous sheet colored white made from a crystallizable polyethylene terephthalate and containing 6 % by weight of titanium dioxide, based on the weight of the polymer, is thermoformed analogously to Example 1.
The titanium dioxide is of the rutile type and is coated with an inorganic ~ 18 coating of Al2O3 and with an organic coating of polydimethylsiloxane. The titanium dioxide has a mean particle diameter of 0.2 ~m.
The white-colored sheet has the following property profile:
-Thickness : 5 mm - Coloration : white - Surface gloss, 1 st side : 119 (measurementangle 20~) 2nd side : 117 - Lighttransmission : 0 %
- Whiteness : 120 - Surface defects per m2 : none - Charpy impact strength an at 23~C : no break - Izod notched impact strength ak at 23~C : 4.9 kJ/m2 -Crystallinity : 0 %
The thermoforming parameters and temperatures are selected analogously to Example 1. Owing to the greater sheet thickness and the heat absorption behavior as a consequence of the white coloration, the 20 thermoforming cycle time is 95 seconds, with 50 seconds being required for preheating with top and bottom heat and the thermoforming operation and 45 seconds being required for cooling with spray water.
The shaped article has the following properties:
- Color : white - Lighttransmission : 0 %
- Surface gloss, 1 st side : 108 (measurementangle 20~) 2nd side : 113 - Whiteness : 1 18 - Shrinkage : 0.6 %
-Crystallinity : 0 %
- Charpy impact strength an at 23~C : no break - Izod notched impact strength ak at 23~C : 4.8 kJ/m2 - Charpy impact strength an at 40~C : 88 kJ/m2 - Izod notched impact strength ak at 40~C : 2.4 kJ/m2 Comparative Example 1:
A transparent, amorphous PMMA sheet from Rohm (E3~Plexiglas GS) is thermoformed analogously to Exampie 1.
10 The PMMA sheet has the following property profile:
-Thickness : 4 mm - Surface gloss, 1st side : 138 (measurementangle 20~) 2nd side : 136 - Lighttransmission : 93.8 %
-Clarity : 99.8 %
-Haze : 0.5%
- Surface defects perm2 : none - Density : 1.19 g/cm3 - Charpy impact strength an at 23~C : 16 kJ/m2 - Izod notched impact strength ak at 23~C : 1.5 kJ/m2 With the thermoforming parameters, temperatures and thermoforming cycle times analogously to Example 1, it is impossible to produce a shaped 25 article.
The PMMA sheet with a thickness of 4 mm can only be thermoformed under the following, significantly less economic conditions:
- Sheet size : 1000 mm x700 mm - Sheetthickness : 4 mm - Mold area : 960 mm x 660 mm - Thermoforming depth : 200 mm - Predrying : 10 hours at 125~C
- ~Aold temperature : 50~C
- Heater output, top heating : 75 %
- Heater output, bottom heating : 65 %
- Preheating with top and bottom heating/
thermoforming : 89 sec 5 - Vacuum : yes - Sheet temperature : 1 80~C
- Cooling with spray water : 70 sec - Temperature of the shaped article on removal from the mold : 50~C
The thermoforming cycle time for shaping an article is significantly longer, at 159 seconds, which greatly reduces the productivity in the continuous thermoforming machines usual today compared with the amorphous molding made from a PET sheet. In addition, the sheet must have a 15 significantly higher temperature during thermoforming, so that the energy costs are higher compared with the amorphous molding made from PET.
In particular, it is necessary to dry the sheet for several hours at temperatures above 1 00~C in a special oven before the thermoforming process in order to remove the absorbed water. All the air in the oven must 20 be replaced approximately six times per hour so that the steam can escape. Without predrying, the molding produced from the PMMA sheet has unacceptable surface defects as a consequence of included water.
The molding produced from the predried PMMA sheet with a significantly 25 longer thermoforming cycle time has the following properties:
- Color : transparent - Lighttransmission : 90.1 %
- Haze : 2.3 %
- Surface gloss, 1st side : 112 (measurement angle 20~) 2nd side : 120 - Shrinkage : 3 %
- Density : 1.19 g/cm3 - Crystallinity o %
- Charpy impact strength an at 23~C : 15 kJ/m2 - Izod notched impact strength ak at 23~C : 1.4 kJ/m2 - Charpy impact strength an at -40~C : reproducible values - Izod notched impact strength ak at -40~C : not measurable (strong scattering) Compared with the amorphous PET molding, the molding produced has significantly greater shrinkage and significantly poorer impact strength and notched impact strength even at room temperature. In addition, dangerous 10 splinters with sharp edges are formed on breakage, which occurs easily.
Comparative Example 2:
A transparent, amorphous polycarbonate sheet from GE Plastics 15 (~'Lexan 121 ) is thermoformed analogously to Example 1.
The PC sheet has the following property profile:
- Thickness : 4 mm - Surface gloss, 1st side : 176 (measurement angle 20~) 2nd side : 174 - Lighttransmission : 89 %
- Clarity : 99.1 %
- Haze : 0.5 %
- Surface defects perm2 : none - Density : 1.20 g/cm3 - Charpy impact strength an at 23~C : no break - Izod notched impact strength ak at 23~C : 10 kJ/m2 30 With the thermoforming parameters, the low temperatures and the short thermoforming cycle times without predrying analogously to Example 1, it is impossible to produce a shaped article.
The PC sheet with a thickness of 4 mm can only be thermoformed under the following, significantly less economic conditions:
- Sheet size : 1000 mm x 700 mm - Sheetthickness : 4 mm - Mold area : 960 mm x 660 mm -Thermoforming depth : 200 mm -Predrying : 11 hoursat126~C
- Mold temperature : 70~C
- Heater output, top heating : 80 %
- Heater output, bottom heating : 80 %
- Preheating with top and bottom heating/
thermoforming : 85 sec - Vacuum : yes - Sheet temperature : 1 90~C
- Cooling with spray water : 70 sec - Temperature of the shaped article on removal from the mold : 70~C
Compared with the examples, the thermoforming cycle time for shaping an 20 article from a PC sheet is significantly longer, which greatly reduces the productivity in the continuous thermoforming machines usual today. In addition, the sheet must have a significantly higher temperature during thermoforming, so that the energy costs are higher compared with the amorphous molding made from PET. As in the case of PMMA, it is also 25 necessary in the case of PC to predry the sheet for several hours at temperatures of 125 + 3~C in a fan-assisted oven before the thermoforming process in order to remove the absorbed water. All the air in the oven must be replaced approximately six times per hour so that the steam can escape. \Nithout predrying, the article shaped from the PC
30 sheet has an unacceptable appearance.
The molding produced from the predried PC sheet in a significantly less economical manner has the following properties:
~ CA 02233988 1998-04-03 r -Color : transparent - Lighttransmission : 87.2 %
-Haze : 3.1 %
- Surface gloss, 1st side : 148 (measurement angle 20~) 2nd side : 159 - Shrinkage : approx. 5 %
- Density : 1.20 g/cm3 -Crystallinity : 0 %
- Charpy impact strength an at 23~C : no break - Izod notched impact strength ak at 23~C : 9 kJ/m2 - Charpy impact strength an at-40~C : no break - Izod notched impact strength ak at -40~C : 5 kJ/m2 Compared with the amorphous PET molding, the molding produced has significantly greater shrinkage.
Comparative Example 3:
A molding having a crystallization of about 35 % is produced analogously to Example 1 of EP-A-0 471 528. As described in EP-A-0 471 528, the thermoforming cycle times are again significantly longer than for the amorphous PET molding. In addition, the mold must have a temperature of about 160~C so that crystallization takes place. Such high mold temperatures cannot be achieved using usual water heating. An oil-heated or electrically heated mold is required here, which, owing to the high temperature, must not be made of epoxy resin or wood, but instead of aluminum.
The PET molding having a crystallization of about 35 % has the following properties:
- Color : white, as a consequence of r crystallization - Light transmission : 34 %
- Haze : not measurable as a consequence of ini-5 - Clarity tiated crystallization - Surface gloss, 1st side : 90 (measurementangle 20~) 2nd side : 98 - Shrinkage : approx. 6 %
- Density : 1.37 g/cm3 10 - Crystallinity : approx. 35 %
- Charpy impact strength an at 23~C : 87 kJ/m2 - Izod notched impact strength ak at 23~C : 2.3 kJ/m2 The PET molding having a crystallization of about 35 % is always opaque 15 as a consequence or crystallization. Consequently, transparent or transparently colored embodiments cannot be provided. In addition, this molding exhibits high shrinkage and significantly worse notched impact strength and impact strength even at room temperature.
Description Amorphous molding made from a polyethylene terephthalate sheet 5 The invention relates to a process for the production of amorphous moldings from amorphous polyethylene terephthalate sheets, and to the amorphous moldings themselves. The moldings can either be transparent, transparently colored or opaquely colored. The moldings have good mechanical properties in addition to good optical properties.
Amorphous, transparent sheets having a thickness of from 1 to 20 mm are well known. These two-dimensional structures comprise amorphous, non-crystallizable thermoplastics. Typical examples of such thermoplastics which can be converted into sheets are, for example, polyvinyl chloride 15 (PVC), polycarbonate (PC) and polymethyl methacrylate (PMMA). These semifinished products are produced on so-called extrusion lines (cf.
PolymerWerkstoffe, Volume ll, Technologie 1, p. 136, Georg Thieme Verlag, Stuttgart, 1984). The pulverulent or granular raw material is melted in an extruder. After extrusion, the amorphous thermoplastics can easily be 20 shaped via polishing stacks or other shaping tools as a consequence of their viscosity, which continuously increases with decreasing temperature.
After shaping, amorphous thermoplastics then have adequate stability, i.e.
a high viscosity, in order to be self-supporting in the calibration die.
However, they are still sufficiently soft to be shaped by the die. The melt 25 viscosity and inherent rigidity of amorphous thermoplastics are so high in the calibration die that the semifinished product does not collapse in the calibration die before cooling. In the case of easily decomposed materials, for example PVC, special processing aids, for example processing stabilizers against decomposition and lubricants against excessive internal 30 friction and thus uncontrollable warming, are necessary during extrusion.
External lubricants are necessary to prevent sticking to walls and rolls.
The processing of PMMA is carried out using, for example, a vented extruder to enable removal of moisture.
-The production of transparent sheets from amorphous thermoplastics sometimes requires expensive additives, which can migrate and can cause production problems owing to evaporation and surface coatings on the semifinished product. PVC sheets can be recycled only with difficulty or 5 using special neutralization or electrolysis processes. PC and PMMA
sheets can likewise only be recycled with difficulty and only with loss or extreme impairment of the mechanical properties.
In addition to these disadvantages, PMMA sheets also have extremely 10 poor impact strength and splinter on fracture or mechanical loading.
Furthermore, PMMA sheets are readily combustible, which means that they cannot be employed, for example, for internal applications and in exhibitions.
15 PMMA and PC sheets furthermore cannot be shaped when cold; PMMA
sheets disintegrate to form dangerous splinters, while PC sheets undergo hairline cracking and stress whitening.
PMMA and PC sheets absorb moisture. The moisture content increases during production, transport and storage. Although the performance of the extruded sheet is not impaired, the increased moisture causes bubbles and other surface defects and impairment of the properties during shaping (thermoforming and vacuum forming). Before mechanical shaping, these sheets must be dried for between 1 hour and 48 hours, depending on the sheet thickness, at temperatures above 120~C in a fan-assisted oven (cf.
Technicai Handbook GE Plastics Structured Products, Solid Lexan sheets), which is energy- and time-consuming.
German Patent Application 195221 18.4 (prior art as defined in 3 ll 30 PatG) describes an amorphous, transparent sheet having a thickness in the range from 1 to 20 mm whose principal constituent is a crystallizable thermoplastic and which contains at least one UV light stabilizer. In addition to high UV stability, the sheet is distinguished both by good optical properties, for example high light transmission, high surface gloss, low haze and high clarity, and by good mechanical properties, for example high impact strength and high breaking strength.
German Patent Application 195 22 120.6 (prior art as defined in 3 ll PatG) describes an amorphous, transparently colored, UV-stabilized sheet made from a crystallizable thermoplastic whose thickness is in the range from 1 to 20 mm. The sheet contains at least one UV light stabilizer and at least one polymer-soluble dye. In addition to high UV stability, the sheet is distinguished by good optical and mechanical properties.
German Patent Application 195 22 119.2 (prior art as defined in 3 ll PatG) describes an amorphous, colored, UV-stabilized sheet made from a crystallizable thermoplastic whose thickness is in the range from 1 to 20 mm. The sheet contains at least one UV light stabilizer and at least one organic and/or inorganic pigment as colorant. In addition to high UV
stability, the sheet is distinguished by homogeneous optical properties and good mechanical properties.
EP-A-0 471 528 describes a process for shaping an article made from a polyethylene terephthalate (PET) sheet. The PET sheet is heat-treated on both sides in a thermoforming mold in a temperature range between the glass transition temperature and the melting point. The shaped PET sheet is removed from the mold when the degree of crystallization of the shaped PET sheet is in the range from 25 to 50 %. The PET sheets disclosed in EP-A-0 471 528 have a thickness of from 1 to 10 mm. Since the thermoformed moldings produced from this PET sheet have high crystallization, there is no possibility of obtaining a transparent article. Themolding is always opaque to light. In addition, the thermoformed molding has poor mechanical properties, in particular poor impact strength, owing to the crystallization.
US-A-3,496,143 describes the vacuum forming of a PET sheet with a thickness of 3 mm whose crystallization is in the range from 5 to 25 %.
However, the crystallinity of the vacuum-formed molding is greater than 25 %. Since the sheet described and the molding vacuum-formed therefrom are partially crystalline, there is again no possibility here of obtaining a transparent article or a transparent sheet. In addition, both the sheet and the molding vacuum-formed therefrom have poor mechanical 5 properties, in particuiar poor impact strength, owing to the crystallization.
Processes for the production of transparent or clear moldings from amorphous or partially crystalline PET sheets having a thickness of up to 6 mm by vacuum forming are also described in Austrian Patent Specification Nos. 304 086 and 285 160.
However, the PET employed in Austrian Patent No. 304 086 is glycol-modified PET (PET-G), i.e. a copolymer comprising ether and ester units.
PET-G is naturally amorphous and can only be crystallized with difficulty. In addition, the PET employed here has a crystallization temperature -15 corresponding to the post- (cold) crystallization temperature TCN- of at least 160~C.
Austrian Patent No. 285 160 uses a PET sheet having a thickness of 3 mm and a degree of crystallization of 21 %. The molding obtained therefrom was consequently at least partially crystalline and thus no longer 20 transparent.
The object of the present invention was therefore to provide thermoformed moldings which are either transparent, colored in a transparent manner or colored in an opaque manner and have a thickness in the range from 1 to 25 20 mm with optical and mechanical properties which essentially correspond to those of amorphous polyethylene terephthalate sheets.
The good mechanical properties include, in particular, high impact strength and high breaking strength.
The good optical properties of the transparent or transparently coloredembodiment include, for example, high light transmission and a homogeneous appearance.
In addition, the novel molding should be recyclable, economic to produce and have low flammability so that it can also be used, for example, for indoor applications.
5 In a particular embodiment, the molding is also UV-resistant so that it is suitable for outdoor applications.
This object is achieved by a process for the production of an amorphous molding which comprises warming, thermoforming, cooling and 10 subsequently demolding an amorphous sheet having a thickness in the range from 1 to 20 mm, preferably in the range from 1 to 10 mm, whose principal constituent is crystallizable polyethylene terephthalate.
Amorphous sheets having a thickness in the range from 1 to 20 mm whose 15 principal constituent is crystallizable polyethylene terephthalate and which are suitable as starting materials for the novel process, and their production, are disclosed, for example, in German Patent Applications 195 19 579.5,195 19 578.7,195 19 577.9, 195 22 118.4,195 22 120.6, 195 22 119.2, 195 28 336.8,195 28 334.1 and 195 28 333.3.
For the purposes of the present invention, the term crystallizable polyethylene terephthalate is taken to mean - crystallizable polyethylene terephthalate homopolymers, - crystallizable polyethylene terephthalate copolymers, 25 - crystallizable polyethylene terephthalate compounds, - crystallizable polyethylene terephthalate recyclate and - other variants of crystallizable polyethylene terephthalate.
Preferred starting materials for the production of the amorphous sheet are 30 polyethylene terephthalate polymers having a post- (cold) crystallization temperature TCN in the range from 120 to 158~C, in particular from 130 to 158~C.
For the purposes of the present invention, amorphous sheets are taken to -mean those which are non-crystalline, although the crystallizable thermoplastic employed preferably has a crystallinity of from 25 to 65 %.
Non-crystalline, i.e. essentially amorphous, means that the degree of crystallinity is generally less than 5 %, preferably less than 2 %, particularly5 preferably 0 %.
In contrast to sheets made from conventional materials, for example polymethyl methacrylate (PMMA) and polycarbonate (PC), sheets whose principal constituent is crystallizable polyethylene terephthalate generally 10 do not need to be dried before thermoforming, but instead can be processed directly without the usual preparatory steps for processing.
The warming or heating of the sheet can be effected using any heating device known to the person skilled in the art for thermoforming. The sheet 15 is preferably heated using a hot-air oven or an infra-red radiator.
In order to achieve extremely quick and uniform heating of the sheet, the latter is preferably heated on both sides, i.e. with top and bottom heat.
20 The sheet is preferably heated until the sheet temperature is in the range from 120~ to 160~C, preferably in the range from 130~ to 145~C.
If large-area sheets are used, sagging of the sheets during heating can occur. In this case, the sheets are preferably supported by means of 25 compressed air during the heating.
Typical heating times for transparent sheets whose principal constituent is polyethylene terephthalate are, for example, about 1/3 of the time necessary for PMMA and PC sheets.
Differences can occur depending on the nature and efficiency of the available heating. Colored sheets may have additional time differences owing to the different heat absorption behavior.
Warming is followed by shaping, also referred to as thermoforming. The heated sheets employed can be thermoformed by standard methods, like other materials.
5 In order to ensure uniform thickness distribution over the entire material during the thermoforming process, the usual methods can be used, for example variation of the temperature profile of the sheets, specific vacuum settings or blowing up a dome as precursor to shaping.
10 In addition, it is advantageous for the production of an amorphous molding for the temperature of the mold to be kept below 80~C, preferably below 60~C.
Furthermore, the time between the end of the heating period and the 15 completion of the shaping operation should be kept short. A mold design having a maximum number of vent holes and the maximum diameter (for example 1 mm) is therefore preferably recommended.
After completion of the shaping operation, the molding should be cooled 20 rapidly using air or air/spray water.
The subsequent demolding is preferably not carried out until the molding is at a temperature below 60~C.
25 Owing to the low and uniform shrinkage, which is preferably < 1.0 %, the molding produced can easily be removed from the mold. Subsequent shrinkage of the molding with time does not occur. The molding remains dimensionally stable.
30 The invention furthermore relates to an amorphous, thermoformed molding having a thickness in the range from 1 to 20 mm whose principal constituent is a crystallizable polyethylene terephthalate and whose surface gloss, measured in accordance with DIN 67530 (measurement angle 20~), is greater than 90, preferably greater than 100.
~ CA 02233988 1998-04-03 For the purposes of the present invention, the term amorphous molding is taken to mean a molding whose crystallinity is generally less than 5 %, preferably less than 2 %, particularly preferably 0 %.
5 The novel moldings preferably do not break during measurement of the Charpy impact strength an (measured in accordance with ISO 179/1 D).
In addition, the Izod notched impact strength ak (measured in accordance with ISO 180/1A) of the moldings is preferably in the range from 3.0 to 10 8.0 kJ/m2, particularly preferably in the range from 4.0 to 6.0 kJ/m2.
The amorphous, thermoformed molding can be either transparent, colored in a transparent manner or colored in an opaque manner.
15 In the transparent embodiment, the novel thermoformed molding has a light transmission, measured in accordance with ASTM D 1003, of greater than 80 %, preferably greater than 84 %.
The haze of the molding, measured in accordance with ASTM D 1003, is 20 less than 15 %, preferably less than 11 % and the clarity of the molding, determined at an angle of less than 2.5~ (ASTM D 1003), is preferably greater than 94 %, particularly preferably greater than 96 %.
In the transparently colored embodiment, where the molding contains at 25 least one dye which is soluble in the polyethylene terephthalate, preferably in a concentration of from 0.001 to 20 % by weight, based on the weight of the crystallizable polyethylene terephthalate, the light transmission, measured in accordance with ASTM D 1003, is in the range from 5 to 80 %, preferably in the range from 10 to 70 %.
The haze of the molding, measured in accordance with ASTM D 1003, is in the range from 2 to 40 %, preferably in the range from 3 to 35 %, and the clarity of the molding, determined at an angle of less than 2.5~ (ASTM
D 1003), is preferably greater than 90 %, particularly preferably greater than 92 %.
In the opaquely colored embodiment, where the molding contains at least one organic and/or inorganic pigment as colorant and, if desired, 5 additionally a soluble dye, where the concentration of the pigment is preferably in the range from 0.5 to 30 % by weight, based on the weight of the crystallizable polyethylene terephthalate, the light transmission, measured in accordance with ASTM D 1003, is less than 5 %.
10 Suitable soluble dyes are disclosed, for example, in German Patent Application 195 19 578.7, and suitable organic and/or inorganic pigments as colorants are disclosed, for example, in German Patent Application 195 19 577.9.
15 In a preferred embodiment, the amorphous, thermoformed molding contains at least one UV light stabilizer, where the concentration of the UV
stabilizer is preferably in the range of 0.01 to 5 % by weight, based on the weight of the crystallizable polyethylene terephthalate.
20 Suitable UV light stabilizers are disclosed, for example, in German Patent Applications 195 22 118.4,195 22 120.6 and 195 22 119.2.
Measurements have furthermore shown that the novel molding has low combustibility and low flammability, so that it is also suitable for indoor 25 applications and in exhibitions.
Furthermore, the novel molding can easily be recycled without environmental pollution and without impairment of the mechanical properties, which means that it is suitable, for example, for use as 30 temporary advertising signs or other advertising articles.
The surprising multiplicity of excellent properties make the novel amorphous molding highly suitable for a multiplicity of different uses, for example for interior room panels, for exhibitions and exhibition articles, for . CA 02233988 1998-04-03 -signs, for protective glazing of machines and vehicles, in shop fitting and shelf construction, as advertising articles, as menu holders, as basketball backboards, as room dividers, for aquaria and as brochure and newspaper holders.
In the UV-stabilized embodiment, the novel amorphous molding is also suitable for outdoor applications, for example for greenhouses, roofing systems, glazing systems, safety glass, external cladding, covers, for applications in the construction sector, illuminated advertising profiles, 10 balcony cladding, roof exits and caravan windows.
In addition, it has been found, surprisingly, that the novel amorphous, thermoformed moldings have good mechanical properties even at low temperatures of down to 40~C without impairment of the optical properties.
15 The good mechanical properties include, inter alia, high breaking strength, high notched jmpact strength, excellent tensile behavior and excellent flexural behavior.
The novel moldings can therefore also advantageously be used in 20 refrigeration systems.
Examples of refrigeration systems or refrigeration equipment are domestic and commercial electric refrigerators and freezers, compressor refrigerators, milk cooling systems, chill cabinets, blood storage refrigerators, mortuary refrigeration systems, medical cooling equipment 25 and laboratory freezers.
The invention is described in greater detail below with reference to working examples without this representing a limitation.
30 The individual properties are measured in accordance with the following standards or by the following processes.
-Measurement methods Surface gloss:
5 The surface gloss is measured in accordance with DIN 67 530. The reflector value is measured as a core optical parameter for the surface of a sheet. In accordance with ASTM-D 523-78 and ISO 2813 standards, the angle of incidence is set at 20~. A light beam hits the planar test surface at the set angle of incidence and is reflected or scattered thereby. The light 10 beams hitting the photoelectric receiver are indicated as proportional electrical quantities. The measurement value is dimensionless and must be given together with the angle of incidence.
Light transmission:
15 The light transmission is taken to mean the ratio between the total amount of transmitted light and the amount of incident light.
The light transmission is measured using a "Hazegard plus" instrument in accordance with ASTM D 1003.
Haze and clarity:
Haze is the percentage of transmitted light deflected from the incident ray bundle by an average of more than 2.5~. The clarity is measured at an angle of less than 2.5~.
The haze and clarity arre measured using a "Hazegard plus" instrument in accordance with ASTM D 1003.
Whiteness The whiteness is determined using an "ELREPHO" electric remission photometer from Zeiss, Oberkochem (DE), standard illuminant C, 2~
standard observer. The whiteness is defined as -W=RY+3RZ-3RX.
(W = whiteness, RY, RZ and RX = corresponding reflection factors when the Y, Z and X color measurement filter respectively is used). White 5 standard is a barium sulfate disk (DIN 5033, Part 9).
Surface defects:
The surface defects are determined visually.
10 Charpy impact strength an:
This parameter is determined in accordance with ISO 179/1 D.
Izod notched impact strength ak:
The Izod notched impact strength ak is measured in accordance with ISO 180/1 A.
Density:
The density is determined in accordance with DIN 53479.
20 SV (DCA) and IV (DCA):
The standard viscosity SV (DCA) is measured in accordance with DIN 53728 in dichloroacetic acid.
The intrinsic viscosity (IV) is calculated as follows from the standard 25 viscosity (SV) IV (DCA) = 6.67 x 10~ SV (DCA) + 0.118.
Thermal properties:
The thermal properties, such as crystalline melting point Tm~ crystallization temperature range Tc, after- or cold-crystallization temperature TCN and glass transition temperature Tg are measured by differential scanning calorimetry (DSC) at a heating rate of 10~C/min.
Molecular weight and polydispersity:
The molecular weights Mw and Mn and the resultant polydispersity MW/Mn are measured by gel permeation chromatography (GPC).
Weathering (on both sides), UV stability:
The UV stability is tested as follows in accordance with ISO 4982 test specification:
Test instrument : Atlas Ci 65 Weather-O-Meter 10 Test conditions : ISO 4892, i.e. artificial weathering Exposure time : 1000 hours (perside) Exposure : 0.5 W/m2, 340 nm Temperature : 63~C
Relative atmospheric 15 humidity : 50 %
Xenon lamp : inner and outer filters made of borosilicate Exposure cycle : 102 minutes UV light, then 18 minutes UV light with water spraying of the samples, then a further 102 minutes of UV light, etc.
The examples and comparative examples below each use single-layer sheets produced on the extrusion line described in the abovementioned German Patent Applications.
Example 1:
An amorphous, transparent sheet made from a crystallizable polyethylene terephthalate whose preparation is described in German Patent Application 195 35 180.0, having the following property profile:
-Thickness : 4 mm - Surface gloss, 1st side : 178 ~ CA 02233988 l998-04-03 (measurement angle 20~) 2nd side : 172 - Lighttransmission : 89.4 %
- Clarity : 99.7 %
-Haze : 2.1%
- Surface defects perm2 : none - Crystallinity : 0 %
- Density : 1.33 g/cm3 - Charpy impact strength an at 23~C : no break - Izod notched impact strength ak at 23~C : 4.7 kJ/m2 is thermoformed on a UA 100 g vacuum thermoforming machine from Illig, Heilbronn, with the following parameters:
- Sheet size : 1000 mm x 700 mm - Sheetthickness : 4 mm - Mold area : 960 mm x 660 mm -Thermoforming depth : 200 mm - Predrying : 0 min (unnecessary) - Mold temperature : 50~C
- Heater output, top heating : 65 %
- Heater output, bottom heating : 45 %
- Preheating with top and bottom heating/
thermoforming : 38 sec - Vacuum : yes - Sheet temperature : 140~C
- Cooling with spray water : 40 sec - Temperature of the shaped article on removal from the mold : 50~C
30 The entire thermoforming cycle therefore takes only 78 seconds.
The shaped article has the following properties:
- Color : transparent - Lighttransmission : 87.8 %
- Haze : 3.4 %
- Surface gloss, 1st side : 150 (measurement angle 20~) 2nd side : 162 - Shrinkage : 0.5 %
- Density : 1.33 g/cm3 -Crystallinity : 0 %
- Charpy impact strength an at 23~C : no break - Izod notched impact strength ak at 23~C : 4.7 kJ/m2 - Charpy impact strength an at 40~C : 78 kJ/m2 - Izod notched impact strength ak at 40~C : 2.4 kJ/m2 Example 2 15 An amorphous, transparent sheet made from a crystallizable polyethylene terephthalate and containing 0.6 % by weight of the UV stabilizer 2,2'-methylenebis(6-(2H-benzotriazol-2-yl)4-(1,1,3,3-tetramethylbutyl)-phenol (~IDTinuvin 360 from Ciba-Geigy), based on the weight of the polymer, is thermoformed analogously to Example 1.
20 The UV-stabilized sheet has the following property profile:
- Thickness : 4 mm - Surface gloss, 1st side : 176 (measurement angle 20~) 2nd side : 174 - Lighttransmission : 89.1 %
- Clarity : 99.5 %
-Haze : 2.3%
- Surface defects per m2 : none - Crystallinity : 0 %
- Density : 1.33 g/cm3 - Charpy impact strength an at 23~C : no break - Izod notched impact strength ak at 23~C : 4.6 kJ/m2 The thermoforming parameters, the temperatures and the thermoforming cycle time are selected analogously to Example 1.
The shaped, UV-stabilized article has the following properties:
- Color : transparent - Lighttransmission : 86.9 %
- Haze : 3.6 %
- Surface gloss, 1st side : 148 (measurement angle 20~) 2nd side : 159 - Shrinkage : 0.5 %
- Density : 1.33 g/cm3 -Crystallinity : o %
- Charpy impact strength an at 23~C : no break - Izod notched impact strength ak at 23~C : 4.5 kJ/m2 - Charpy impact strength an at -40~C : 79 kJ/m2 - Izod notched impact strength ak at -40~C : 2.2 kJ/m2 Example 3:
20 An amorphous sheet colored transparent red, made from a crystallizable polyethylene terephthalate and containing 2 % by weight of the soluble dye Solvent Red 138, an anthraquinone derivative from BASF (~'Thermoplast G), based on the weight of the polymer, is thermoformed analogously to Example 1.
The sheet colored transparent red has the following property profile:
- Thickness : 2 mm - Coloration : red transparent - Surface gloss, 1st side : 130 (measurement angle 20~) 2nd side : 127 - Lighttransmission : 35.8 %
- Clarity : 99.1 %
- Haze : 3.5 %
- Surface defects per m2 : none - Charpy impact strength an at 23~C : no break - Izod notched impact strength ak at 23~C : 4.1 kJ/m2 -Crystallinity : 0 %
- Density : 1.33 g/cm3 The thermoforming parameters and temperatures are selected analogously to Example 1. Owing to the lower sheet thickness, the thermoforming cycle time is only 37 seconds, with 17 seconds required for preheating with top 10 and bottom heat and for the thermoforming operation and 20 seconds required for cooling with spray water.
The shaped article has the following properties:
- Color : red transparent - Light transmission : 34.9 %
-Haze : 3.8%
- Surface gloss, 1 st side : 118 (measurement angle 20~) 2nd side : 126 - Shrinkage : 0.4 %
- Density : 1.33 g/cm3 - Crystallinity : ~ %
- Charpy impact strength an at 23~C : no break - Izod notched impact strength ak at 23~C : 4.0 kJ/m2 - Charpy impact strength an at -40~C : 69 kJ/m2 - Izod notched impact strength ak at -40~C : 2.0 kJ/m2 Example 4:
30 An amorphous sheet colored white made from a crystallizable polyethylene terephthalate and containing 6 % by weight of titanium dioxide, based on the weight of the polymer, is thermoformed analogously to Example 1.
The titanium dioxide is of the rutile type and is coated with an inorganic ~ 18 coating of Al2O3 and with an organic coating of polydimethylsiloxane. The titanium dioxide has a mean particle diameter of 0.2 ~m.
The white-colored sheet has the following property profile:
-Thickness : 5 mm - Coloration : white - Surface gloss, 1 st side : 119 (measurementangle 20~) 2nd side : 117 - Lighttransmission : 0 %
- Whiteness : 120 - Surface defects per m2 : none - Charpy impact strength an at 23~C : no break - Izod notched impact strength ak at 23~C : 4.9 kJ/m2 -Crystallinity : 0 %
The thermoforming parameters and temperatures are selected analogously to Example 1. Owing to the greater sheet thickness and the heat absorption behavior as a consequence of the white coloration, the 20 thermoforming cycle time is 95 seconds, with 50 seconds being required for preheating with top and bottom heat and the thermoforming operation and 45 seconds being required for cooling with spray water.
The shaped article has the following properties:
- Color : white - Lighttransmission : 0 %
- Surface gloss, 1 st side : 108 (measurementangle 20~) 2nd side : 113 - Whiteness : 1 18 - Shrinkage : 0.6 %
-Crystallinity : 0 %
- Charpy impact strength an at 23~C : no break - Izod notched impact strength ak at 23~C : 4.8 kJ/m2 - Charpy impact strength an at 40~C : 88 kJ/m2 - Izod notched impact strength ak at 40~C : 2.4 kJ/m2 Comparative Example 1:
A transparent, amorphous PMMA sheet from Rohm (E3~Plexiglas GS) is thermoformed analogously to Exampie 1.
10 The PMMA sheet has the following property profile:
-Thickness : 4 mm - Surface gloss, 1st side : 138 (measurementangle 20~) 2nd side : 136 - Lighttransmission : 93.8 %
-Clarity : 99.8 %
-Haze : 0.5%
- Surface defects perm2 : none - Density : 1.19 g/cm3 - Charpy impact strength an at 23~C : 16 kJ/m2 - Izod notched impact strength ak at 23~C : 1.5 kJ/m2 With the thermoforming parameters, temperatures and thermoforming cycle times analogously to Example 1, it is impossible to produce a shaped 25 article.
The PMMA sheet with a thickness of 4 mm can only be thermoformed under the following, significantly less economic conditions:
- Sheet size : 1000 mm x700 mm - Sheetthickness : 4 mm - Mold area : 960 mm x 660 mm - Thermoforming depth : 200 mm - Predrying : 10 hours at 125~C
- ~Aold temperature : 50~C
- Heater output, top heating : 75 %
- Heater output, bottom heating : 65 %
- Preheating with top and bottom heating/
thermoforming : 89 sec 5 - Vacuum : yes - Sheet temperature : 1 80~C
- Cooling with spray water : 70 sec - Temperature of the shaped article on removal from the mold : 50~C
The thermoforming cycle time for shaping an article is significantly longer, at 159 seconds, which greatly reduces the productivity in the continuous thermoforming machines usual today compared with the amorphous molding made from a PET sheet. In addition, the sheet must have a 15 significantly higher temperature during thermoforming, so that the energy costs are higher compared with the amorphous molding made from PET.
In particular, it is necessary to dry the sheet for several hours at temperatures above 1 00~C in a special oven before the thermoforming process in order to remove the absorbed water. All the air in the oven must 20 be replaced approximately six times per hour so that the steam can escape. Without predrying, the molding produced from the PMMA sheet has unacceptable surface defects as a consequence of included water.
The molding produced from the predried PMMA sheet with a significantly 25 longer thermoforming cycle time has the following properties:
- Color : transparent - Lighttransmission : 90.1 %
- Haze : 2.3 %
- Surface gloss, 1st side : 112 (measurement angle 20~) 2nd side : 120 - Shrinkage : 3 %
- Density : 1.19 g/cm3 - Crystallinity o %
- Charpy impact strength an at 23~C : 15 kJ/m2 - Izod notched impact strength ak at 23~C : 1.4 kJ/m2 - Charpy impact strength an at -40~C : reproducible values - Izod notched impact strength ak at -40~C : not measurable (strong scattering) Compared with the amorphous PET molding, the molding produced has significantly greater shrinkage and significantly poorer impact strength and notched impact strength even at room temperature. In addition, dangerous 10 splinters with sharp edges are formed on breakage, which occurs easily.
Comparative Example 2:
A transparent, amorphous polycarbonate sheet from GE Plastics 15 (~'Lexan 121 ) is thermoformed analogously to Example 1.
The PC sheet has the following property profile:
- Thickness : 4 mm - Surface gloss, 1st side : 176 (measurement angle 20~) 2nd side : 174 - Lighttransmission : 89 %
- Clarity : 99.1 %
- Haze : 0.5 %
- Surface defects perm2 : none - Density : 1.20 g/cm3 - Charpy impact strength an at 23~C : no break - Izod notched impact strength ak at 23~C : 10 kJ/m2 30 With the thermoforming parameters, the low temperatures and the short thermoforming cycle times without predrying analogously to Example 1, it is impossible to produce a shaped article.
The PC sheet with a thickness of 4 mm can only be thermoformed under the following, significantly less economic conditions:
- Sheet size : 1000 mm x 700 mm - Sheetthickness : 4 mm - Mold area : 960 mm x 660 mm -Thermoforming depth : 200 mm -Predrying : 11 hoursat126~C
- Mold temperature : 70~C
- Heater output, top heating : 80 %
- Heater output, bottom heating : 80 %
- Preheating with top and bottom heating/
thermoforming : 85 sec - Vacuum : yes - Sheet temperature : 1 90~C
- Cooling with spray water : 70 sec - Temperature of the shaped article on removal from the mold : 70~C
Compared with the examples, the thermoforming cycle time for shaping an 20 article from a PC sheet is significantly longer, which greatly reduces the productivity in the continuous thermoforming machines usual today. In addition, the sheet must have a significantly higher temperature during thermoforming, so that the energy costs are higher compared with the amorphous molding made from PET. As in the case of PMMA, it is also 25 necessary in the case of PC to predry the sheet for several hours at temperatures of 125 + 3~C in a fan-assisted oven before the thermoforming process in order to remove the absorbed water. All the air in the oven must be replaced approximately six times per hour so that the steam can escape. \Nithout predrying, the article shaped from the PC
30 sheet has an unacceptable appearance.
The molding produced from the predried PC sheet in a significantly less economical manner has the following properties:
~ CA 02233988 1998-04-03 r -Color : transparent - Lighttransmission : 87.2 %
-Haze : 3.1 %
- Surface gloss, 1st side : 148 (measurement angle 20~) 2nd side : 159 - Shrinkage : approx. 5 %
- Density : 1.20 g/cm3 -Crystallinity : 0 %
- Charpy impact strength an at 23~C : no break - Izod notched impact strength ak at 23~C : 9 kJ/m2 - Charpy impact strength an at-40~C : no break - Izod notched impact strength ak at -40~C : 5 kJ/m2 Compared with the amorphous PET molding, the molding produced has significantly greater shrinkage.
Comparative Example 3:
A molding having a crystallization of about 35 % is produced analogously to Example 1 of EP-A-0 471 528. As described in EP-A-0 471 528, the thermoforming cycle times are again significantly longer than for the amorphous PET molding. In addition, the mold must have a temperature of about 160~C so that crystallization takes place. Such high mold temperatures cannot be achieved using usual water heating. An oil-heated or electrically heated mold is required here, which, owing to the high temperature, must not be made of epoxy resin or wood, but instead of aluminum.
The PET molding having a crystallization of about 35 % has the following properties:
- Color : white, as a consequence of r crystallization - Light transmission : 34 %
- Haze : not measurable as a consequence of ini-5 - Clarity tiated crystallization - Surface gloss, 1st side : 90 (measurementangle 20~) 2nd side : 98 - Shrinkage : approx. 6 %
- Density : 1.37 g/cm3 10 - Crystallinity : approx. 35 %
- Charpy impact strength an at 23~C : 87 kJ/m2 - Izod notched impact strength ak at 23~C : 2.3 kJ/m2 The PET molding having a crystallization of about 35 % is always opaque 15 as a consequence or crystallization. Consequently, transparent or transparently colored embodiments cannot be provided. In addition, this molding exhibits high shrinkage and significantly worse notched impact strength and impact strength even at room temperature.
Claims
Claims 1. A process for the production of an amorphous molding, which comprises warming to a temperature in the region of 120 to 160°C, thermoforming, cooling and subsequently demolding an amorphous sheet having a thickness in the range from 1 to 20 mm whose principal constituent is crystallizable polyethylene terephthalate.
2. The process as claimed in claim 1, wherein the amorphous sheet has a thickness in the range from 1 to 10 mm.
3. The process as claimed in claim 1 or 2, wherein the sheet is warmed by means of a hot-air oven or an infra-red radiator.
5. The process as claimed in claim 4, wherein the sheet is warmed until the sheet temperature is in the range from 130° to 145°C.
6. The process as claimed in any one of claims 1 to 5, wherein the temperature of the mold during thermoforming is kept below 80°C.
7. The process as claimed in claim 6, wherein the temperature of the mold during thermoforming is kept below 60°C.
&. The process as claimed in any one of claims 1 to 7, wherein the molding is cooled using air or air/spray water.
9. The process as claimed in any one of claims 1 to 8, wherein the molding is demolded when the temperature of the molding is below 80°C.
10. The process as claimed in claim 9, wherein the molding is demolded when the temperature of the molding is below 60°C.
11. The process as claimed in claim 1, wherein the polyethylene terephthalate employed has a post- (cold) crystallization temperature T CN
in the range from 120°C to 158°C.
12. An amorphous, thermoformed molding having a thickness in the range from 1 to 20 mm whose principal constituent is a crystallizable polyethylene terephthalate, wherein the surface gloss, measured in accordance with DIN 67530 (measurement angle 20°), is greater than 90.
13. A molding as claimed in claim 12, wherein no break occurs during measurement of the Charpy impact strength a n in accordance with ISO 179/1D.
14. A molding as claimed in claim 12 or 13, wherein the Izod notched impact strength a k, measured in accordance with ISO 180/1A, is in the range from 3.0 to 8.0 kJ/m2.
15. A molding as claimed in any one of claims 12 to 14, which is transparent, transparently colored or opaquely colored.
16. A molding as claimed in any one of claims 12 to 15, which contains at least one UV light stabilizer.
17. A molding as claimed in claim 16, wherein the concentration of the UV stabilizer is in the range from 0.01 to 5 % by weight, based on the weight of the crystallizable polyethylene terephthalate.
18. A molding as claimed in claim 12, wherein the polyethylene terephthalate employed has a post- (cold) crystallization temperature T CN
in the range from 120°C to 158°C.
19. The use of an amorphous, thermoformed molding as claimed in any one of claims 12 to 18 indoors or outdoors or in refrigeration systems.
2. The process as claimed in claim 1, wherein the amorphous sheet has a thickness in the range from 1 to 10 mm.
3. The process as claimed in claim 1 or 2, wherein the sheet is warmed by means of a hot-air oven or an infra-red radiator.
5. The process as claimed in claim 4, wherein the sheet is warmed until the sheet temperature is in the range from 130° to 145°C.
6. The process as claimed in any one of claims 1 to 5, wherein the temperature of the mold during thermoforming is kept below 80°C.
7. The process as claimed in claim 6, wherein the temperature of the mold during thermoforming is kept below 60°C.
&. The process as claimed in any one of claims 1 to 7, wherein the molding is cooled using air or air/spray water.
9. The process as claimed in any one of claims 1 to 8, wherein the molding is demolded when the temperature of the molding is below 80°C.
10. The process as claimed in claim 9, wherein the molding is demolded when the temperature of the molding is below 60°C.
11. The process as claimed in claim 1, wherein the polyethylene terephthalate employed has a post- (cold) crystallization temperature T CN
in the range from 120°C to 158°C.
12. An amorphous, thermoformed molding having a thickness in the range from 1 to 20 mm whose principal constituent is a crystallizable polyethylene terephthalate, wherein the surface gloss, measured in accordance with DIN 67530 (measurement angle 20°), is greater than 90.
13. A molding as claimed in claim 12, wherein no break occurs during measurement of the Charpy impact strength a n in accordance with ISO 179/1D.
14. A molding as claimed in claim 12 or 13, wherein the Izod notched impact strength a k, measured in accordance with ISO 180/1A, is in the range from 3.0 to 8.0 kJ/m2.
15. A molding as claimed in any one of claims 12 to 14, which is transparent, transparently colored or opaquely colored.
16. A molding as claimed in any one of claims 12 to 15, which contains at least one UV light stabilizer.
17. A molding as claimed in claim 16, wherein the concentration of the UV stabilizer is in the range from 0.01 to 5 % by weight, based on the weight of the crystallizable polyethylene terephthalate.
18. A molding as claimed in claim 12, wherein the polyethylene terephthalate employed has a post- (cold) crystallization temperature T CN
in the range from 120°C to 158°C.
19. The use of an amorphous, thermoformed molding as claimed in any one of claims 12 to 18 indoors or outdoors or in refrigeration systems.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE19537107A DE19537107A1 (en) | 1995-10-05 | 1995-10-05 | Amorphous molded body made of a polyethylene terephthalate plate |
| DE19537107.0 | 1995-10-05 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2233988A1 true CA2233988A1 (en) | 1997-04-10 |
Family
ID=7774098
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002233988A Abandoned CA2233988A1 (en) | 1995-10-05 | 1996-09-26 | Amorphous moulding from a polyethylene terephthalate plate |
Country Status (17)
| Country | Link |
|---|---|
| EP (1) | EP0853543A1 (en) |
| JP (1) | JPH11512667A (en) |
| KR (1) | KR19990064018A (en) |
| CN (1) | CN1198705A (en) |
| AU (1) | AU7214996A (en) |
| BG (1) | BG102356A (en) |
| BR (1) | BR9611159A (en) |
| CA (1) | CA2233988A1 (en) |
| CZ (1) | CZ103198A3 (en) |
| DE (1) | DE19537107A1 (en) |
| HU (1) | HUP9900082A3 (en) |
| MX (1) | MX9802731A (en) |
| NO (1) | NO981385L (en) |
| OA (1) | OA10677A (en) |
| PL (1) | PL325993A1 (en) |
| TR (1) | TR199800638T1 (en) |
| WO (1) | WO1997012750A1 (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| IT1307930B1 (en) | 1999-01-26 | 2001-11-29 | Sinco Ricerche Spa | TRANSPARENT ARTICLES IN POLYESTER RESIN (MG32). |
| EP2067683A3 (en) | 2007-12-03 | 2009-12-16 | Innova Patent GmbH | Method for producing a wall section or a cover for a cabin or a seat of a ropeway system |
| JP6177069B2 (en) * | 2013-09-25 | 2017-08-09 | 三菱電機株式会社 | Electricity meter |
| CN114619657A (en) * | 2022-01-22 | 2022-06-14 | 东莞市思纯塑胶制品有限公司 | One-time crystallization method in PLA film, crystallization mold and crystallization equipment thereof |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE1479801B2 (en) * | 1964-12-03 | 1974-08-08 | Enka Glanzstoff Ag, 5600 Wuppertal | Process for the production of molded articles from polyethylene terephthalate |
| AT304086B (en) * | 1970-08-07 | 1972-12-27 | Sandoz Ag | Process for the production of transparent moldings by the deep-drawing process |
| US4123473A (en) * | 1975-10-23 | 1978-10-31 | Allied Chemical Corporation | Transparent sheets and containers formed from polycarbonate-polyester blends and formation thereof |
| US5318811A (en) * | 1992-12-30 | 1994-06-07 | Welex Incorporated | Food tray and method of making the same |
-
1995
- 1995-10-05 DE DE19537107A patent/DE19537107A1/en not_active Withdrawn
-
1996
- 1996-09-26 HU HU9900082A patent/HUP9900082A3/en unknown
- 1996-09-26 KR KR1019980702495A patent/KR19990064018A/en not_active Application Discontinuation
- 1996-09-26 PL PL96325993A patent/PL325993A1/en unknown
- 1996-09-26 TR TR1998/00638T patent/TR199800638T1/en unknown
- 1996-09-26 JP JP9513948A patent/JPH11512667A/en active Pending
- 1996-09-26 CZ CZ981031A patent/CZ103198A3/en unknown
- 1996-09-26 AU AU72149/96A patent/AU7214996A/en not_active Abandoned
- 1996-09-26 EP EP96933400A patent/EP0853543A1/en not_active Withdrawn
- 1996-09-26 CN CN96197431A patent/CN1198705A/en active Pending
- 1996-09-26 BR BR9611159-3A patent/BR9611159A/en not_active Application Discontinuation
- 1996-09-26 CA CA002233988A patent/CA2233988A1/en not_active Abandoned
- 1996-09-26 WO PCT/EP1996/004207 patent/WO1997012750A1/en not_active Application Discontinuation
-
1998
- 1998-03-26 BG BG102356A patent/BG102356A/en unknown
- 1998-03-26 NO NO981385A patent/NO981385L/en unknown
- 1998-04-03 OA OA9800038A patent/OA10677A/en unknown
- 1998-04-06 MX MX9802731A patent/MX9802731A/en unknown
Also Published As
| Publication number | Publication date |
|---|---|
| PL325993A1 (en) | 1998-08-17 |
| TR199800638T1 (en) | 1998-06-22 |
| BG102356A (en) | 1999-11-30 |
| EP0853543A1 (en) | 1998-07-22 |
| CZ103198A3 (en) | 1998-07-15 |
| CN1198705A (en) | 1998-11-11 |
| OA10677A (en) | 2002-10-18 |
| BR9611159A (en) | 1999-12-28 |
| WO1997012750A1 (en) | 1997-04-10 |
| MX9802731A (en) | 1998-11-29 |
| DE19537107A1 (en) | 1997-04-10 |
| KR19990064018A (en) | 1999-07-26 |
| NO981385D0 (en) | 1998-03-26 |
| HUP9900082A2 (en) | 1999-03-29 |
| HUP9900082A3 (en) | 1999-12-28 |
| AU7214996A (en) | 1997-04-28 |
| NO981385L (en) | 1998-03-26 |
| JPH11512667A (en) | 1999-11-02 |
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