OA10677A - Amorphous molding from a plate of poly (ethylene terephthalate) - Google Patents

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

010677 can betransparent or

The invention relates to a process for preparing amorphous moldings from amorphous poly (ethylene terephthalate) plates, as well as to the amorphous moldings themselves. The casts are optionally transparent, colored dull colored. In addition to good optical properties, the moldings are characterized by good mechanical properties.

Amorphous, transparent plates having a thickness of between 1 and 20 mm are well known. These two-dimensional products consist of amorphous, noncrystallizable thermoplastics. Typical examples of such thermoplastics that can be formed into plates are, for example, polyvinyl chloride (PVC), polycarbonate (PC) and poly (methyl methacrylate) (PMMA). These semi-finished products are prepared on so-called extrusion units (see Polymer Werkstoffe, Vol II, Technology 1, p. 136, Georg Thieme Verlag, Stuttgart, 1984). The melting of the pulverulent or granulated raw material is carried out in an extruder. The amorphous thermoplastics can be easily converted after extrusion, as the viscosity increases continuously with decreasing temperature, using calenders or other finishing tools. Amorphous thermoplastics then have sufficient stability, ie, high viscosity, after the transformation, to "stand up alone" in the calibration tool. But they are flexible enough30 to be cast by the tool. The infusion viscosity and the stiffness of amorphous thermoplastics are so high in the calibration tool that the semi-product does not collapse before cooling in the calibration tool. In the case of materials which are easily decomposed, such as for example PVC, there is a need in the extrusion step for particular processing aids, such as stabilizers for the purposes of decomposition, and lubricants. ίο 15 20 25 30 against an excessive internal friction and therefore against an uncontrollable reheating. External lubricants are needed to prevent cling to walls and cylinders.

In the implementation of PMMA, for example, to eliminate moisture, a degassing extruder is used.

In the preparation of amorphous thermoplastic transparent plates, additives are required, some of which are expensive, which can migrate and cause production problems due to evaporation and superficial deposits on the semi-finished product. The PVC sheets can only be recycled with difficulty or with the aid of special neutralization or electrolysis processes. Likewise, PC and PMMA plates can only be recycled with difficulty and only at the cost of extreme loss or degradation of mechanical characteristics.

In addition to these disadvantages, the PMMA plates also have extremely low toughness toughness and burst upon breaking or mechanical stressing. In addition, the PMMA plates are easily flammable, so that they can not be used for example for indoor wall cladding and for the construction of exhibition halls.

In addition, it is not possible to cold profile PMMA and PC plates. In cold forming, PMMA plates break into dangerous chips. In cold profiling, filiform cracks and white fracture are formed in PC slabs.

Plates of PMMA and PC absorb moisture, moisture content increases during production, transportation and storage. Admittedly, the performance of the extruded plate is not impaired, but during forming (thermoforming and vacuum forming), it occurs due to increased moisture, bubbles and other surface defects as well as property degradation. Before mechanical processing, these plates must be dried in an air recirculating oven at a temperature above 120 ° C depending on the thickness of the plate for a period of between 1 and 48 hours (see Technisches Handbuch GE Plastics Structured Products, Massive Lexan®-Platten) which consumes a lot of energy and time.

German Patent Application 195 22 118.4 (state of the art according to § 3 II PatG) discloses an amorphous, transparent plate with a thickness in the range of 1 to 20 mm which contains as a main component a crystallizable thermoplastic and is characterized in that it contains a UV stabilizer as a photoprotective agent. In addition to the high UV stability, the plate is characterized by its good optical properties, such as high light transmission, high surface gloss, low turbidity and high image clarity, as well as good mechanical properties such as for example high erythesistance and high resistance to fracture.

German patent application 195 22 120.6 (state of the art according to § 3 II PatG) discloses a transparent, UV stabilized, amorphous plate of a crystallizable thermoplastic, the thickness of which is in the range of 1 to 20 mm. . The plate contains at least one UV stabilizer as a photoprotective agent and at least one polymer soluble dye. In addition to high UV stability, the plate is characterized by good optical and mechanical properties.

In the German patent application 19 5 22 119.2 (state of the art according to § 3 II PatG) is disclosed an amorphous plate, colored, stabilized against UV, in a crystallizable unthermoplastic whose thickness is in the range of 1 to 20 mm. The plate contains at least one UV stabilizer as a photoprotective agent and at least one organic and / or inorganic pigment as a colorant. Apart from the high UV stability, the plate is characterized by good homogeneous properties both optical and mechanical.

EP-A-0 471 528 discloses a process for forming an object from a poly (ethylene terephthalate) (PET) plate. Both sides of the PET plate are heat treated in a stamping tool at a temperature range between the glass transition temperature and the melting temperature. The molded PET plate is extracted from the mold when the degree of crystallization of the molded PET plate is within a range of 25% to 50%. The PET sheets disclosed by EP-A-0 471 528 have a thickness of 1 to 10 mm. Since the stamped molding prepared from this plate is highly crystalline, there is no possibility of obtaining a transparent object. The molding is always opaque. In addition, pressed molding presents, due to crystallization, poor mechanical properties, in particular poor resilience.

US-A-3,496,143 discloses deep-vacuum deep drawing of a 3 mm PET wafer having a crystallization range of 5% to 25%. However, the crystallinity of the molded molding is greater than 25%. Since the writing plate and stamped molding from this plate are partially crystalline, there is also no possibility in this case of obtaining a transparent object or a transparent plate. In addition, as well as the plate that the molding stamped from it, present because of crystallization, mechanical malfunctions, in particular a weaker-resilience.

Methods of preparing moldings

Transparencies, or clear from amorphous or partially crystalline PET plates, with a thickness up to 6 mm by vacuum drawing, are further described in Austrian Patent Specifications Nos. 304,086 and 285,160.

However, for the PET used in AT-PS No. 304 086, it is a glycol-treated PET (PET-G), that is to say, a copolymer consisting of ethereal units. of ester units. PET-G is by its nature amorphous and only difficult to crystallize. In addition, the PET used here has a crystallization temperature-corresponding to the postcrystallization temperature (cold) TCN - of at least 160 ° C.

According to the AT-PS Patent Specification No. 285 160, a plate with a thickness of 3 mm, which has a degree of crystallization of 21%, is used. Indeed, the molding obtained from this plate is therefore at least partially crystalline and is therefore no longer transparent. The object of the present invention is to prepare pressed moldings, thus thermoformed, which may optionally be transparent, transparent-colored or dull colored, the thickness of which is 1 to 20 mm and the optical and mechanical characteristics of which correspond essentially to those of the poly (terephthalate) plates. ethylene) amorphous.

Good mechanical properties include, in particular, high resilience and high breaking strength.

Among the good optical properties for the transparent or transparent colored embodiment, for example, a particularly high permeability to light and a homogeneous optics are exemplified.

In addition, the plate according to the invention must be recyclable, its preparation must not be expensive, and not easily flammable, so that it can be used for example for the coating of interior walls.

In a particular embodiment, the molding must also be UV stable so that it is also suitable as an outer coating. 010677

This problem is solved by means of a process for preparing an amorphous molding, characterized in that it is heated, thermoformed, cooled and finally demolded amorphous plate, with a thickness in the range of 1 to 20 mm, preferably in the range of 1 to 10 mm comprising poly (ethylene terephthalate) as the main component.

Amorphous plates with a thickness in the range of 1 to 20 mm, which contain as a main component a crystallizable polyethylene terephthalate, which are suitable as starting material for the process according to the invention, and their preparation, are described by the 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. ethylene) is understood to mean ethylene) ethylene)

Crystallizable thermoplastics according to the invention are polycrystalline terephthalate homopolymers, poly (terephthaleacrystallizable) copolymers, poly (terephthaleacrystallizable) compounds, crystallizable recyclable poly (ethylene terephthalate) products and other poly (ethylene terephthalate) variants. crystallizable.

Preferred starting materials for the preparation of the amorphous plate are the poly (ethylene terephthalate) polymers with a temperature drop-crystallization (cold crystallization) TCN in the range of 120 to 158 ° C, especially 130 to 158 ° C. .

For the purposes of the present invention, amorphous plates are understood to mean such plates which, although the crystallizable thermoplastic used has a crystallinity of between 25% and 65%, are not crystalline. Non-crystalline, i.e. essentially amorphous, means that the degree of crystallinity is generally less than 5%, preferably less than 2% and more preferably 0%.

Unlike plates from conventional materials, such as polymethyl methacrylate (PMMA) or polycaronate (PC), the plates containing poly (ethylene terephthalate) crystallizable as the main component, generally should not be dried prior to pressing. that is to say, lethermoforming, but we can transform them directly, without the usual preparation transformation steps.

Reheating or heating the plate can be implemented in any heater known to those skilled in the art. For the heating of the plate, it is preferred to use hot air ovens or IR ovens.

In order to obtain as rapid or uniform heating of the plate as possible, it is heated preferably on both sides, that is to say with heating below and above.

The plate is preferably heated until the temperature of the plate is in the range of 120 ° C to 160 ° C, preferably in the range of 130 ° to 145 ° C.

When plates with a large surface area are used, the plates may bend during heating. In this case, the plates are supported during heating, preferably with compressed air.

Typical heating times for transparent plates, which contain polyethylene terephthalate as the main component, are generally necessary for the PMMA and PCL plates.

Deviations may occur depending on the type and efficiency of available heat. Color plates may have additional 010677 time differences due to different heat absorption behavior.

After heating, the forming is done, which is also called thermoforming or stamping. The hot plates can be thermoformed by thermoforming like any other material, using a standard process.

In order to ensure a uniform distribution of the thickness of all the material during the thermoforming, it is possible to take the usual measurements, such as for example the variation of the temperature profile of the plate, the control of the vacuum or blowing of a dome as a precursor .

In addition, to prepare amorphous molding, it is advantageous when the temperature of the tool is maintained below 80 ° C, preferably below 60 ° C.

In addition, the time between the end of the warm-up period and the end of the forming process must be kept short. For this reason, it is recommended to use a tool construction with a maximum number of aeration perforations and a maximum diameter (for example 1 mm).

After completing the forming operation, the molding should be cooled rapidly with air or with air / spray with water.

Subsequent demolding is preferably carried out only when the molding has a temperature below 60 ° C.

Due to a small and uniform shrinkage, which is preferably <1.0%, the molding of the tool can be extracted without problems. There is no post-contraction of the molding over time.

Another object of the invention is a thermoformed, thermoformed mold with a thickness in the range of 1 to 20 mm, which contains poly (terephthalate) as the main component, characterized in that the surface gloss measured according to DIN 67530 (angle 20 ° incidence) is greater than 90, preferably greater than 100. 010677

In the sense of the present invention, amorphous castings are understood to mean such moldings, the crystallinity of which is in general less than 5%, preferably less than 2% and particularly preferably 0%.

The moldings in accordance with the invention preferably do not exhibit a break in the Charpy annual thesilence measurements (measured according to ISO 179 / 1D).

In addition, Izod notched resistance according to Izod (measured according to ISO 180 / 1A) of the molding is preferably in the range of 3.0 to 8.0 kJ / m 2, especially preferably in the range of 4.0 to 6,0kJ / m2.

The amorphous, thermoformed molding can be optionally transparent, pigmented transparent or pigmented deaf.

In the transparent embodiment, the molding according to the invention has a light transmission, measured according to ASTM D 1003, of greater than 80%, preferably greater than 84%.

The turbidity of the molding, measured according to ASTM D 1003, is less than 15%, preferably less than 11%, and the image clarity of the molding, which is also called "clarity", and which is determined at an angle less than 2 5 ° (ASTM D 1003) is preferably greater than 94% and particularly preferably greater than 96%.

In the transparent pigmented embodiment, wherein the molding contains at least one colorant soluble in polyethylene terephthalate preferably in a concentration of 0.001 to 20% by weight based on the weight of the crystallizable polyethylene terephthalate, the light transmission measured according to ASTM D 1003 is in the range of 5 to 80%, preferably 10 to 70%.

The turbidity of the molding, measured according to ASTM D 1003, is in the range of 2 to 40%, preferably in the range of 3 to 35%, and the image clarity of the molding, also known as "clarity". and measured at an angle of 2.5 ° (ASTM D 1003) is preferably greater than 90% and particularly preferably greater than 92%.

In the dull pigmented embodiment, wherein the molding contains an organic and / or inorganic pigment as a colorant and optionally additionally a transparent colorant, the pigment concentration preferably being from 0.5 to 30% by weight based on the weight of the poly (terephthalate) ethylene) crystallizable, the light transmittance measured according to ASTM D 1003 is less than 5%.

Suitable soluble dyes are disclosed, for example, in German Patent Application 195 19 578.7 and organic and / or inorganic pigments as a colorant, for example German Patent Application 195 19 577.9.

In a preferred embodiment, the amorphous thermoformed mold has at least one UV stabilizer as a photoprotective agent, the UV stabilizer concentration is preferably in the range of 0.01 to 5% by weight, based on the weight of the poly (terephthalate). ethylene) crystallizable.

UV stabilizers suitable as photoprotective agents are disclosed, for example, in German Patent Applications 195 22 118.4, 195 22 120.6 and 195 22 119.2.

In addition, the measurements have shown that the mold conforms to the invention is not very combustible and difficult to ignite, so that it lends itself well to internal application and for the construction of exhibition hall.

Therefore, the molding according to the invention is recyclable without problems without polluting the environment and without loss of mechanical properties, that is why it is suitable for example for applications such as short advertising banners or other publicity articles.

Thanks to the surprising number of excellent characteristics, the amorphous molding according to the invention is well suited for many different applications, for example for interior coating, for the construction of exhibition halls and for exhibition articles, panels, machine shielding glasses, exterior cladding, decouvertures, for applications in the construction sector, for illuminated advertising, for the cladding of decks, roofs and for caravan windows.

In addition, it has surprisingly been found that the amorphous stamped moldings according to the invention, even at low temperatures down to -40 ° C., exhibit good mechanical properties, without the optical properties being impaired. Good mechanical properties, among others, include high resilience, notch resilience, excellent tensile strength and flexural strength.

It is therefore advantageous to use moldings according to the invention in cooling systems. Examples of cooling systems or installations are domestic and industrial refrigerators and freezers, compression refrigerators, milk coolers, refrigerated display cases, blood bag refrigerators, mortuary refrigerators, medical coolers and freezers for the laboratory. The invention is explained in more detail on the basis of embodiments, without being limited to these examples.

The measurements of the different properties were carried out according to the following standards or processes.

METHODS OF MEASUREMENT

brightness

The gloss of the surface is determined according to DIN 67530. The reflection is measured as an optical characteristic of the surface of a plate. On the basis of ASTM-D 523-78 and ISO 2813, the angle of incidence is set at 20 °. The light ray touches the controlled surface beneath the established angle of incidence and is reflected or biendispersed. The light rays are picked up by the photoelectronic receiver and indicated as electrical magnitudes. The measured value is dimensionless and should be indicated together with the angle of incidence.

Transmission of light:

By transmission of light, we must hear the contribution of all the light transmitted to the quantity of light sent.

The light transmission is measured with a measuring device "Hazegrad plus" according to ASTM 1003.

Turbidity and image sharpness

Turbidity is the percentage of light transmitted which deviates by more than 2.5 ° from the midpoint of the incident light beam. The sharpness of the image is determined at an angle smaller than 2.5 °.

Turbidity and image sharpness are measured using the "Hazegard plus" measuring device according to the ASTM 1003 form.

Degree of white

The degree of whiteness is determined by the electric remission photometer "ELREPHO" of the company Zeiss, Oberkochem (Germany), standard illuminant C, 2 ° reference observer. The degree of white is defini

DB = RY + 3RZ - 3RX DB = white degree, RY, RZ, RX = corresponding reflectance using a Y, Zet X colorimetric filter. As a white standard, a barium sulphate molded part is used (DIN 5033, part 9 ). 13 01067? Superficial defects:

The surface defects are visually evaluated. Resilience an Charpy:

This quantity is determined according to ISO179 / 1D. Resilience ak Izod:

The notched resilience, Izod notch resistance according to ISO 180 / 1A, is measured.

Density:

The density is determined according to DIN 53479. VS (ADA), VI (ADA):

The standard viscosity VS (ADA) according to DIN 53728 is measured in dichloroacetic acid.

The intrinsic viscosity is calculated from the standard viscosity as follows VI (ADA) = 6.67 × 10 -4VS (ADA) + 0.118

Thermal properties:

The thermal properties, such as the melting point of crystallites Tm, the temperature range of crystallization Tc, the settling-crystallization temperature (of cold crystallization) TCN and the glass transition temperature Tg are measured by differential scanning calorimetry (DSC). ) with a heating rate of 10 ° C / min.

Molar mass, polydispersity:

The molar masses Mw and Mn and the resulting polydispersity Mw / Mn are measured by gel permeation chromatography. 14 010677

Exposure to intempen (both sides), UV stability:

The UV stability is checked according to the ISO 4892 test specification as follows:

Test apparatusTest conditions

Duration of irradiation

Irradiation

Temperature

Humidity of airrelative

Xenon lamp

Irradiation cycles

In the examples

Atlas Ci 64 Weather Ometer ISO 4892, weather-resistant artificial weather 1000 hours (per face)

0.5 W / m2, 340 nm63 ° C 50% inner and outer borosilicate filter 102 minutes UV rays, then 18 minutes UV rays, samples in water mist, then to new 102 minutes derayons UV, etc. and comparative examples after it In each case these are monolayer plates, the German patent applications described above were prepared in the extrusion assembly. by 10

Example 1

An amorphous, transparent plate from a crystallizable poly (ethylene terephthalate), described by German Patent Application 195 35 180.0, having the following characteristics: - Thickness: 4 mm - surface gloss, face 1: 178 - ( angle of incidence 20 °), face 2: 172 - Light transmission: 89.4% - Image clarity: 99.7% - Turbidity: 2.1% - Superficial defects per m2: none - Crystallinity: 0% - Density: 1.33 g / cm: 15 010677 Charpy Resilience at 23 ° C: no break Resilience with ak cut -47 kJ / m2

Izod at 23 ° C '' is stamped on a machine <Illig / Heilbronn company, following parameters: - Plate dimensions - Plate thickness - Forming surface - Stamping heightPres drying - Molding tool temperature

Radiator powerhigh heating

Radiator powerhigh heating

Pre-heating with higher and lower heating / stamping - Vacuum - Plate temperature - Cooling with water spray

Temperature of the object as a result of the extraction of the vacuum thermoforming type UA 100 g, with: 1000 mm × 1000 mm: 4 mm: 960 mm × 660 mm: 200 mm: 0 min. (not necessary)

: 50 ° C: 65%: 45%: 38 sec. : Yes

: 140 ° C: 40 sec

50 ° C

In doing so, the entire 5 of 78 seconds only. The following formed object:

Color

Transmission of lightTurbidity

Surface brightness, face 1 (20 ° angle of incidence), faceRetrait / contraction

DensityCrystallinity

Charpy Resilience at 23 ° C stamping cycle is the characteristics: transparent: 87.8%: 3.4%: 150 2: 162: 0.5%: 1.33 g / cm3: 0%: no break 16 010677

Resilience with akIzod notch at 23 ° C

Charpy Resilience at -40 ° C

Resilience with akIzod notch at -40 ° C: 4.7 kJ / m2: 78 kJ / m2: 2.4 kJ / m2

Example 2

In a similar manner to Example 1, an amorphous, transparent plate is stamped from a poly (ethylene terephthalate), which contains 0.6% by weight of UV stabilizer, 2,2'-methylenebis - (6- (2H-benzotriazol-2-yl) -4- (1,1,3,3-tetramethylbutyl) -phenol (®Tinuvin 360 from Ciba-Geigy Company), based on the weight of the polymer: 10 - Thickness : 4 mm - surface brightness, face 1: 176 - (20 ° incidence angle), face 2: 174 - light transmission: 89.1% - image clarity: 99.5% - Turbidity: 2.3% - Superficial defects per m2: none - Crystallinity: 0% - Density: 1.33 g / cm3 - Resilience Charpy at 23 ° C: no breakage - Resilience with notch ak: 4.6 kJ / m2 Izod at 23 ° C The draw temperature parameters and the duration of the drawing cycle of analogous to Example 1 are chosen. The formed object, stabilized with UV, has the following properties:

Color

Transmission of lightTurbidity

Surface brightness, face 1 (angle of incidence 20 °), face 2Retrait / contraction

DensityCrystallinity transparent86.9% 3.6% 148 159 0.5% 1.33 g / cm3 0% 010677 17: no break: 4.5 kJ / m2: 79 kJ / m2: 2.2 kJ / m2

Charpy resilience at 23 ° Celsius with akIzod cut at 23 ° C

Charpy Resilience at -40 ° C

Resilience with akIzod notch at -40 ° C

Example 3

In a similar manner to Example 1, an amorphous, red-transparent pigmented plate is pressed from a crystallizable polyethylene terephthalate, which contains 2% by weight of the Solventrot 138 soluble dye, an anthraquinone derivative of the BASF company (®Thermoplast G), relative to the weight of the polymer.

The transparent red pigmented plate has the following characteristics:

Thickness: 2mm - Pigmentation: red-transparent - Surface gloss, face 1: 130 - (angle of incidence 20 °), side 2: 127 - Light transmission: 35,8% - Image sharpness (clarity ): 99.1 - Turbidity: 3.5% - Superficial defects per m2: none - Charpy resilience at 23 ° C: no breakage - Iz Iz Iz notch toughness at 23 ° C: 4.1 kJ / m2 - Crystallinity 0% Density The parameters d: 1.33 g / cm 3 and the temperatures are selected in a similar manner to Example 1. Because of the lower thickness of the plate, the stamping cycle does not last. than 37 seconds, requiring only 20 seconds for preheating with bottom and top heating, as well as for stamping and spray cooling with water. 010677 18 The shape object has the following properties:

Color

Transmission of lightTurbidity

Surface brightness, face 1 (20 ° angle of incidence), faceRetrait / contraction

Density

crystallinity

Charpy resilience at 23 ° Celsius with akIzod cut at 23 ° C

Charpy Resilience at -40 ° C

Resistance with akIzod notch at -40 ° C: transparent red: 34.9%: 3.8%: 118 2: 126: 0.4%: 1.33 g / cm3: 0%: no rupture: 4.0 kJ / m2: 69 kJ / m2: 2.0 k J / m2

Example 4

In a similar manner to Example 1, a transparent, white pigmented plate was pressed from a poly (ethylene terephthalate) which contained 6% by weight of titanium dioxide based on the weight of the polymer. The titanium dioxide is of rutile type and coated with an inorganic coating of Al2O3 and an organic coating of polydimethylsiloxane. Titanium dioxide has an average particle diameter of 0.2 gm.

The white pigmented plate has the following characteristics:

Thickness

Pigmentation

Surface brightness, face 1 (incidence angle 20 °), side 2Transmission of light Degree of white Surface defects per m2

Resilience Charpy at 23 ° C

Resistance with notch akIzod at 23 ° C: 5 mm: white: 119: 117: 0%: 120: none: no break: 4.9 k J / m2

Crystallinity 010677 19 50 the

The stamping parameters and the temperatures are chosen in a similar manner to Example 1. Because of the greater thickness of the plate and the heat absorption behavior due to the pigmentation in white, the stamping cycle is 95.degree. seconds, seconds are required for top and bottom heat preheating as well as for stamping, 45 seconds for cooling with water spray. The formed object presents the following:

Color

Light Transmission Surface brightness, face 1 (20 ° angle of incidence), face 2 Degree of white

Withdrawal / contractionCrystallinity Resilience an Charpy at 23 ° CRelience with notch ak characteristics

Izod at 23 ° C

Charpy resilience at -40 ° CRelience with akIzod cut at -40 ° C white0% 1081131180,6% 0% no break4,8 kJ / m2 88 kJ / m22,4 kJ / m2

Comparative Example 1

In a similar manner to Example 1, an amorphous, transparent PMMA plate was pressed from Rohm (© Plexiglas GS).

The PMMA plate has the profile of the following features:

Thickness: 4 mm Surface gloss, face 1: 138 (angle of incidence 20 °), face 2: 136 Light transmission: 93.8% Image clarity: 99.8 Turbidity: 0.5 % Surface defects per m2: none Density: 1.19 g / cm; 20 010677 Charpy Resilience at 23 ° C: 16 kJ / m2

Resistance with notch ak -15 kJ / m2Izod at 23 ° C

With the stamping parameters, temperatures and cycle times similar to Example 1, it was not possible to prepare a formed object.

The thermoforming of the 4 mm thick PAMMA plate can be carried out under the following conditions, which are essentially uneconomical.

Dimensions of the plate

Thickness of the plate

Forming surface

Drawing height

Pre-drying

Temperature of the stamping tool

Power of the upper heating transmitter

Transmitter powerhigher heating

Preheating with upper heaters and lower heating / stamping

Plate temperature

Spray cooling with water

Temperature of the object during removal of the tool 1000 mm x 700 mm4 mm 960 mm x 660 mm200 mm

10 h at 125 ° C50 ° C 75% 65% 89 sec. Yes

180 ° C 7 0 sec

50 ° C

With 159 seconds, the duration of the stamping cycle for forming the object is essentially longer, which greatly reduces the productivity of the current 10 continuous thermoforming machines operating continuously, compared to amorphous moldings from a PET plate. In addition, the plate must have a substantially higher temperature during stamping, thus the energy cost is higher compared to amorphous PET moldings. In particular, it is necessary to dry the plate prior to the pressing process for several hours at a temperature of 100 ° C in a special oven to remove the water absorbed. In doing so, the total amount of air in the oven should be changed about 6 times per hour so that water vapor can escape. Without pre-drying, the molding prepared from the PMMA plate has unacceptable surface defects as a result of the incorporated water.

The molding prepared from the PMMA pre-dried plate with a substantially longer stamping cycle time has the following characteristics: - Color: transparent - Light transmission: 90.1% - Turbidity: 2.3% - Surface gloss, face 1: 112 - (angle of incidence 20 °), face 2: 120 - Removal / post-contraction: 3% - Density: 1.19 g / cm2 - Crystallinity: 0% - Resilience yr Charpy at 23 ° C: 15 kJ / m2 - Resilience with notch ak. Izod at 23 ° C 1.4 kJ / m2 - Resilience at Charpy at -40 ° C no data - Resilience with notch izod Izod at -40 ° C reproduciblemeasurable (strongecarts) The prepared cast has compared to amorphous PET casts a post-contraction significantly higher (said shrinkage) and, already at room temperature, uneerience and resilience with noticeably more bad notch. As a result, it is formed during the break that occurs easily, dangerous bursts at sharp edges.

Comparative Example 2

A similar procedure is followed in Example 1

transparent polycarbonate plate from GE Company

Plastics (®Lexan 121). 22 06777

The place of PC presents the following characteristics:

Thickness: 4 mm Surface gloss, face 1: 176 (20 ° angle of incidence), face 2: 174 Light transmission: 89% Image clarity: 99.1 Turbidity: 0.5% Defects surface area per m2: none Density: 1.20 g / cm3 Resilience an Charpy at 23 ° C: no rupture Resilience with ak Izod notch at 23 ° C: 10 kJ / m2

With the stamping parameters, the weak

temperatures, short stamping cycles and without pre-drying in a manner similar to Example 1, it was not possible to prepare a formed object. The 4 mm thick polycarbonate sheet can be thermoformed only under the following conditions, which are essentially uneconomic: - Plate dimensions: 1000 mm x 700 mm - Plate thickness: 4 mm - Forming surface: 960 mm x 660 mm - Stamping height: 200 mm - Pre-drying: 11 h at 126 ° C - Molding tool temperature: 70 ° C - Transmitter powerhigher heating: 80% Transmitter powerlowheating: 80% Preheating with upper heating and lower heating / stamping: 85 sec. - Vacuum: yes - Plate temperature: 190 ° C - Spray cooling with water: 70 sec - Object temperature during tool extraction: 70 ° C

70 ° C 010677 23

Compared to the examples, the stamping cycle for forming an object from a PC plate is substantially longer, which greatly reduces the productivity of modern continuous thermoforming machines. Furthermore, the plate must present a substantially higher temperature for the forming process, which results in an increase in the cost of energy compared to the amorphous PET moldings. As for the PMMA, for the PC also, it is necessary to steam the plate before the stamping operation for several hours at a temperature of 125 ± 3 ° C, in order to eliminate the absorbed water. About 6 times all the air must be replaced in the oven so that the water vapor can escape. Without stoving, the object formed from the PC plate has unacceptable optical characteristics.

The molding produced in a substantially less economical manner from the parboiled PC board has the following characteristics: - Color: transparent - Transmission of light: 87.2% - Turbidity: 3.1% - Surface brightness, side 1: 148 - (angle of incidence 20 °), side 2: 159 - Removal / post-contraction: approx. 5% - Density: 1.20 g / cm3 - Crystallinity: 0% - Charpy Resilience at 23 ° C: no fracture Resilience with Izod notch at 23 ° C: 9 kJ / m2 - Charpy Resilience at - 40 ° C: no breakage - Resistance with notch Izod at -40 ° C: 5 kJ / m2

The prepared molding has significantly higher post-contraction (shrinkage) compared to the amorphous PET molding. 24 010677

Comparative Example 3

In a similar manner to Example 1 of DE-A-0 471 528, a molding is prepared which has a crystallinity of about 35%. As described by EP-A-0 471 528, the described stamping cycles are substantially longer than for the molding of amorphous PET. In addition, the tool must have a temperature of about 160 ° C for crystallization to take place. High tool temperatures can not be achieved with conventional water heaters. To do this, we need a tool heated with oil or electricity, which, because of high temperatures, should not be epoxy resin or wood, but aluminum.

The PET molding with a crystallinity of about 35%, has the following properties:

Color: white, because of crystallization

Transmission of lightTurbidity

Clarity (image sharpness)

Surface brightness, face 1 (20 ° angle of incidence), face 2Retrait / post-contractionMass volume

Crystallinity Resiliency an Charpy at 23 ° CRelience with notch 34% not measurable, because of the crystallization initiated 90 98 approx. 6% 1.37 g / cm3env. 3 5% 87 kJ / m22.3 kJ / m2

Izod at 23 ° C

PET molding with a degree of crystallization of about 35% is still opaque due to crystallization. Therefore, one can not prepare a transparent or transparent pigmented object. In addition, the die also shows a high post-contraction (shrinkage) and noticeably softer and even worse resilience already at ambient temperature.

Claims (17)

25 01 0677 CLAIMS A process for preparing an amorphous molding, characterized in that an amorphous plate is heated to a thickness in the range of 1 to 20 mm, which contains as a main component a polyethylene terephthalate at a temperature of temperature in the range of 120 to 160 ° C, thermoforming is carried out, cooled and then demolded. 2. Method according to claim 1, characterized in that the amorphous plate has a thickness in the range of 1 to 10 mm. 3. A method according to claim 1 or 2, wherein the plate is heated by means of hot air ovens or IR heaters. 4. Process according to claim 3, characterized in that the plate is heated until the temperature of the plate is in the range of 130 ° C to 145 ° C. 20 5. Method according to one of claims 1 to 4, characterized in that in the thermoforming, the temperature of the tool is maintained below 80 ° C. 6. Method according to claim 5, characterized in that in the thermoforming, the temperature of the tool is maintained below 60 ° C. 7. Process according to one of Claims 1 to 6, characterized in that air or air / water is cooled in the spray molding. 8. Process according to one of Claims 1 to 7, characterized in that the molding is demolded when the molding temperature is below 80 ° C. 26 010677 9. A method according to claim 8, characterized in that the molding is demolded, when the molding temperature is less than 60 ° C. Process according to claim 1, characterized in that the polyethylene terephthalate used has a TCN post-crystallization temperature in the range of 120 ° C to 158 ° C. 11. Amorphous molding, thermoformed, with a thickness in the range of 1 to 20 mm, containing as its main component a crystallizable polyethylene terephthalate, characterized in that the gloss of the surface, measured according to DIN 67530 (angle of incidence 20 °), is greater than 90 ° C. 12. Molding according to claim 11, characterized in that there is no breakage during Charpy measurements of the epilscence, measured according to ISO 179 / 1D. 20 13. Molding according to claim 11 or 12, characterized in that the resilience ak according to Izod, measured according to ISO 180 / 1A, is in the range of 3.0 to 8.0 kJ / m2. 25 14. Molding according to one of claims 11 to 13, characterized in that it is transparent, pigmentétransparent or deaf pigmented. 15. Molding according to one of claims 11 to 14, characterized in that it has at least one stabilizerUV as a photoprotective agent. Mold according to claim 15, characterized in that the concentration of UV stabilizer is in the range of 0.01 to 5% by weight, based on the weight of the crystallizable polyethylene terephthalate. 010677 K Mold according to claim 11, characterized in that the poly (ethylene terephthalate) has a post-cold (cold) -crystallization temperature in the range of 120 ° C to 158 ° C. 5 18. Use of an amorphous, thermoformed molding according to one of claims 11 to 17 in the indoor and outdoor uses as well as in cooling systems. 10