CA2050310A1 - Aromatic polyester moulded compacts - Google Patents
Aromatic polyester moulded compactsInfo
- Publication number
- CA2050310A1 CA2050310A1 CA002050310A CA2050310A CA2050310A1 CA 2050310 A1 CA2050310 A1 CA 2050310A1 CA 002050310 A CA002050310 A CA 002050310A CA 2050310 A CA2050310 A CA 2050310A CA 2050310 A1 CA2050310 A1 CA 2050310A1
- Authority
- CA
- Canada
- Prior art keywords
- polyester
- pressure
- polyesters
- sintered body
- powder
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
- 229920000728 polyester Polymers 0.000 title claims abstract description 40
- 125000003118 aryl group Chemical group 0.000 title claims abstract description 17
- 239000000843 powder Substances 0.000 claims abstract description 18
- 230000009477 glass transition Effects 0.000 claims abstract description 10
- VOWWYDCFAISREI-UHFFFAOYSA-N Bisphenol AP Chemical compound C=1C=C(O)C=CC=1C(C=1C=CC(O)=CC=1)(C)C1=CC=CC=C1 VOWWYDCFAISREI-UHFFFAOYSA-N 0.000 claims abstract description 5
- XNGIFLGASWRNHJ-UHFFFAOYSA-N o-dicarboxybenzene Natural products OC(=O)C1=CC=CC=C1C(O)=O XNGIFLGASWRNHJ-UHFFFAOYSA-N 0.000 claims abstract description 5
- 238000000034 method Methods 0.000 claims description 21
- 238000010438 heat treatment Methods 0.000 claims description 8
- 235000010290 biphenyl Nutrition 0.000 claims description 4
- 125000006267 biphenyl group Chemical group 0.000 claims description 4
- YWFPGFJLYRKYJZ-UHFFFAOYSA-N 9,9-bis(4-hydroxyphenyl)fluorene Chemical compound C1=CC(O)=CC=C1C1(C=2C=CC(O)=CC=2)C2=CC=CC=C2C2=CC=CC=C21 YWFPGFJLYRKYJZ-UHFFFAOYSA-N 0.000 claims description 3
- 238000001816 cooling Methods 0.000 claims description 3
- 239000004305 biphenyl Substances 0.000 claims description 2
- 150000004820 halides Chemical class 0.000 claims description 2
- ZUOUZKKEUPVFJK-UHFFFAOYSA-N phenylbenzene Natural products C1=CC=CC=C1C1=CC=CC=C1 ZUOUZKKEUPVFJK-UHFFFAOYSA-N 0.000 claims description 2
- 238000010583 slow cooling Methods 0.000 claims 1
- 239000011521 glass Substances 0.000 abstract description 4
- 238000005245 sintering Methods 0.000 abstract description 4
- 239000002904 solvent Substances 0.000 abstract description 4
- NIHNNTQXNPWCJQ-UHFFFAOYSA-N fluorene Chemical compound C1=CC=C2CC3=CC=CC=C3C2=C1 NIHNNTQXNPWCJQ-UHFFFAOYSA-N 0.000 abstract description 3
- 238000003754 machining Methods 0.000 abstract description 2
- -1 phthalic acid halides Chemical class 0.000 abstract description 2
- 239000011265 semifinished product Substances 0.000 abstract description 2
- 208000036366 Sensation of pressure Diseases 0.000 abstract 1
- 238000004132 cross linking Methods 0.000 abstract 1
- 229920000136 polysorbate Polymers 0.000 abstract 1
- 239000000463 material Substances 0.000 description 6
- 238000003860 storage Methods 0.000 description 4
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 4
- 238000006243 chemical reaction Methods 0.000 description 3
- 239000011888 foil Substances 0.000 description 3
- 238000004519 manufacturing process Methods 0.000 description 3
- FYXKZNLBZKRYSS-UHFFFAOYSA-N benzene-1,2-dicarbonyl chloride Chemical compound ClC(=O)C1=CC=CC=C1C(Cl)=O FYXKZNLBZKRYSS-UHFFFAOYSA-N 0.000 description 2
- 239000002245 particle Substances 0.000 description 2
- VZGDMQKNWNREIO-UHFFFAOYSA-N tetrachloromethane Chemical compound ClC(Cl)(Cl)Cl VZGDMQKNWNREIO-UHFFFAOYSA-N 0.000 description 2
- 125000004203 4-hydroxyphenyl group Chemical group [H]OC1=C([H])C([H])=C(*)C([H])=C1[H] 0.000 description 1
- 239000004215 Carbon black (E152) Substances 0.000 description 1
- 229910000831 Steel Inorganic materials 0.000 description 1
- 238000005299 abrasion Methods 0.000 description 1
- 238000010521 absorption reaction Methods 0.000 description 1
- 150000001298 alcohols Chemical class 0.000 description 1
- 230000001588 bifunctional effect Effects 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 238000005266 casting Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 150000002148 esters Chemical class 0.000 description 1
- 238000001125 extrusion Methods 0.000 description 1
- 229940020445 flector Drugs 0.000 description 1
- RMBPEFMHABBEKP-UHFFFAOYSA-N fluorene Chemical compound C1=CC=C2C3=C[CH]C=CC3=CC2=C1 RMBPEFMHABBEKP-UHFFFAOYSA-N 0.000 description 1
- 239000000727 fraction Substances 0.000 description 1
- 229930195733 hydrocarbon Natural products 0.000 description 1
- 230000005606 hygroscopic expansion Effects 0.000 description 1
- 238000007654 immersion Methods 0.000 description 1
- 238000001746 injection moulding Methods 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- 239000003921 oil Substances 0.000 description 1
- 238000003825 pressing Methods 0.000 description 1
- 238000005096 rolling process Methods 0.000 description 1
- 239000000243 solution Substances 0.000 description 1
- 239000007858 starting material Substances 0.000 description 1
- 239000010959 steel Substances 0.000 description 1
- 238000003786 synthesis reaction Methods 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L67/00—Compositions of polyesters obtained by reactions forming a carboxylic ester link in the main chain; Compositions of derivatives of such polymers
- C08L67/02—Polyesters derived from dicarboxylic acids and dihydroxy compounds
- C08L67/03—Polyesters derived from dicarboxylic acids and dihydroxy compounds the dicarboxylic acids and dihydroxy compounds having the carboxyl- and the hydroxy groups directly linked to aromatic rings
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29B—PREPARATION OR PRETREATMENT OF THE MATERIAL TO BE SHAPED; MAKING GRANULES OR PREFORMS; RECOVERY OF PLASTICS OR OTHER CONSTITUENTS OF WASTE MATERIAL CONTAINING PLASTICS
- B29B13/00—Conditioning or physical treatment of the material to be shaped
- B29B13/007—Treatment of sinter powders
-
- 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
- B29C43/00—Compression moulding, i.e. applying external pressure to flow the moulding material; Apparatus therefor
- B29C43/003—Compression moulding, i.e. applying external pressure to flow the moulding material; 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
- B29C43/00—Compression moulding, i.e. applying external pressure to flow the moulding material; Apparatus therefor
- B29C43/006—Pressing and sintering powders, granules or fibres
-
- 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
- B29C37/00—Component parts, details, accessories or auxiliary operations, not covered by group B29C33/00 or B29C35/00
- B29C2037/90—Measuring, controlling or regulating
-
- 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)
- Chemical & Material Sciences (AREA)
- Health & Medical Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Medicinal Chemistry (AREA)
- Polymers & Plastics (AREA)
- Organic Chemistry (AREA)
- Manufacture Of Macromolecular Shaped Articles (AREA)
- Casting Or Compression Moulding Of Plastics Or The Like (AREA)
Abstract
(57) Abstract Sintered compacts made of aromatic polyesters, produced from diphenols such as 1,1-bis(4-hydroxyphenyl)-1-phenyle-thane or 9,9-bis(4-hydroxaphenyl)fluorene, as well as phthalic acid halides, have one or several glass transition temperatures be-tween 220 and 400 °C and a tensile strength above 40 N/mm2, preferably above 60 N/mm2. In order to produce the sintered compacts, the polyester powder is subjected to a pressure above 3000 N/cm2 in a closed mould. The mould is slowly heated, then maintained for a longer period above the glass temperature and slowly cooled down once again. While it cools, pres-sure can be reduced. Cross linking occurs in the polyester mass during sintering, increasing the fastness to solvents. These sintered compacts are generally useful as semi-finished products or preformed prefabricated elements, from which the de-sired articles can be produced by machining.
Description
2~ 310 A Formed Body of Aromatic Polvesters Backqround of the Invention Field of the Invention The present invention relates to a formed body comprised of one or more aromatic polyesters derived from diphenols and halides of phthalic acid.
DescriPtion of the Prior Art Formed bodies of this kind are known, for example, from European Patent Specifications 64971 and 64972, these being in the form of films produced from a polyester solution by means of a casting process. The polyester described in European Patent Specification 64972 is a polyester based on 1,1-Bis(4-hydroxyphenyl)-1-phenylethane which, as was found, is difficult to process by extrusion or injection molding because of the high process temperatures of 340 to 400C that are required when this is done, whereas the polyester known from European Patent Specification 64971, which is based on 9,9-Bis(4-hydroxyphenyl)fluorene has no melting range at all begins to decompose thermally at a temperature of approximately 400C.
Description of the Invention The object of the present invention is to describe a formed body of the type described in the introduction hereto and which, in contrast to films, can assume a variety of shapes and forms.
This object has been achieved by the shaped body according to the present invention, which is characterized by the fact that it is a sintered body having one or more glass transition points measured by means of DSC, in the range .." . ..
. ~ . ..
.. ~ .. .- -~; - ' 1 ~, -2~3~
~ between 220 and 400C, and a tensile strength, measured ; according to DIN 53455 of greater than 40N/mm , and advan-~ tageously greater than 60N/mm2. It is advantageous that ; the aromatic polyesters that are used are derived from one or more diphenyls of the formula H ~ R ~ OH
, wherein R is a bifunctional hydrocarbon radical contain-ing at least one aromatic or cycloaliphatic ring.
, .
It has been found that with the same type and quality of starting material, relative to cast foils. From this and other facts, which will be discussed subsequently in this specification, one can conclude that the polyester in the sintered body is cross-linked to a certain extent. In a :~ preferred embodiment of the present invention, the sintered body according to the present invention consists essential-ly of an aromatic polyester derived from 9,9-Bis(4-hydroxy-phenyl)fluorene as the diphenyl.
According to another preferred embodiment of the sintered body according to the present invention, this consists essentially of an aromatic polyester derived from 1,1-Bis(4-hydroxyphenyl)-1-phenylethane.
The present invention also refers to an advantageous process for producing the shaped body according to the present invention. This process is characterized in that the aromatic polyester or polyesters in powder form are solidified under pressure; in that the solidified powder is heated slowly to temperatures that are higher than the glass transition point or points of the polyester or poly-esters that are used, this being done while maintaining the pressure; in that the powder mass that has been so com-pressed and which is under pressure is kept at these 2~93~0 temperatures for a specific period of time to form asintered body; and that the body so sintered is then slowly cooled. When this is done, the polyester or polyesters that are in powdered form are advantageously solidified at a pressure of greater than 3,000 N/cm2, although preferably higher than 5,000 N/cm2, such as approximately 10,000 N/cm .
According to advantageous embodiments of the process according to the present invention the slow heating of the compressed polyester powder is effected at a heat-up rate in the range of 1.5 to 4.0C/min and/or the slow cool down of the sintered body is effected at a rate in the range from 0.5 to 2.5C/min.
According to another preferred embodiment of the process according to the present invention, the holding time is in the range of 5-20 min/mm of the mean thickness of the sintered body to be produced, in the direction of the pressure that is applied.
In a further preferred embodiment of the process according to the present invention, the sintered body is cooled at least in part while being acted on by a pressure that is greatly reduced compared to the maximum pressure that is applied.
Some Methods for Carrvinq out the Invention The present invention will be described in greater detail below on the basis of the examples appended hereto.
The sintered bodies produced according to these examples consist of aromatic polyesters as described in European Patent Specifications Nos. 64972 and 64971, namely, . . ~ .
. : !
2~3~
1. Aromatic polyester based on 1,1-Bis(4-hydroxyphenyl)-1-phenylethane and phthalic acid dichloride (iso/tere:
50/50) with a glass transition point of 250C measured by DSC, hereinafter identified as CPE.
2. Aromatic polyester based on 9,9-Bis~4-hydroxy-phenyl)fluorene and phthalic acid dichloride (iso/tere: 50/50) with a glass transition point of 325C measured by DSC, hereinafter identified as FPE.
In order to produce the sintered body one proceeds from the polyesters that are produced in powder form during syn-thesis; these have a mean molecular weight MW of 50,000 to 1,200,000, which corresponds approximately to an inherent viscosity in the range from 0.5 to 3.8 dl/g (measured as described in the above-quoted European Patent Specifica-tions). Of the polyester powder that is produced duringsynthesis, it is the sieve fractions with particle sizes of smaller than 600 ~m, preferably however between 50 and 400 ~m that are used.
Because of their small particle sizes, these powder frac-tions exhibit good sinterability. By eliminating the finest fractions, it has, however, been possible to ensure that the bulk density is not too small, for this would be disadvantageous for the pressing technology.
The production of a sintered body of CPE using a so-called pressure sintering process will be described in greater detail below.
A heated mold is used to produce a plate-shaped sintered body measuring 200 x 220 x 4 mm. After the mold has been preheated to 150C, an appropriate quantity of CPE powder which has been previously dried for several hours at a temperature of 150C in a vacuum oven is placed in the cavity of the lower half of the mold as a filling with a 2~3~
bulk density of 0.35 g/cm3, whereupon the mold is closed by the upper half of the mold, which extends into the mold cavity. The mold is then placed in a press and the CPE
powder is compressed at a pressure of 5,000 N/cm2; the mold is then heated slowly, i.e., at a heating rate of approxi-mately 2C/min, to 270C, which is to say to a temperature above the glass transition point of the CPE powder of 250C, whereupon this temperature is maintained for approx-imately 60 min. Next, the mold is cooled down at a rate of approximately 1C/min to a temperature of 230C; then the pressure is reduced to a low value of approximately 20 N/cm2, that is meant to ensure no more than good contact for thermal loss, whereupon the mold is cooled to 50C, whereupon the sintered body is removed from the mold. The sintered body so obtained has a glass conversion point of 250C, as measured by ASTM D 3418-82, and a density of 1.21 g/cm .
A sintered body of FPE powder can be produced in the same way. Unlike the production of a CPE sintered body, using FPE, this is done at a holding temperature of 330C (higher than the glass transition point of 325C), during cooling the pressure is released at 290C. The FPE sintered body obtained in this way has a glass conversion point of 325C
and a density of 1.22 g/cm3.
The sintered bodies of CPE and FPE have an amber-like colour and are resistant to alcohols, oils, and greases.
As previously stated, polyesters are cross-linked during the sintering process:
A cast foil and a sintered body are produced from CPE and FPE, each with a mean molecular weight MW = approximately 500,000. After the film or sintered body material have been redissolved, the foil material exhibited in molecular ~ , :
..
6 22~3~Q
weight MW of 500,000, whereas that of th~ sintered body material has fallen to a value of MW = 50,000. In contrast - to what could perhaps be assumed, namely, that because of the now lower molecular weight of the sintered body, its resistance to solvent would also be lower, the sintered body has a greater resistance to specific solvents compared to the film material. For example, it was shown that after immersion in carbon tetrachloride for a period of 90 hours in the case of CPE the film absorbs twice as much solvent as the sintered body and, in the case of FPE, the film absorbs 9 times as much.
An improved process for production by sintering is described below. In this process, a mold that is not self-heating, but which can be locked under pressure, is used.
After being filled with the polyester powder (CPE or FPE) the mold is installed in a press where the material is compressed to approximately 10,000 N/cm2 and the mold is locked under pressure, so that even after the mold is taken out of the press the two halves of the mold continue to exert considerable pressure on the material. The mold is then heated slowly in an oven, i.e., at a heating rate of 2/min to 270C (in the case of CPE) or to 330C (in the case of FPE), when, in order to produce a sintered plate that is 4 mm thick, this temperature is maintained for a period of 60 min. Thereafter, the oven heating is switched off and the mold is allowed to cool. After reaching a temperature of 20C beneath the particular glass conversion point, the mold is cooled still more outside the oven, to a temperature of 50C, when the finished sintered body is removed.
In producing sintered bodies it is important to both heat and cool the mold slowly. The permissible heating and cooling rates are smaller the greater the thickness of the sintered body that is to be produced. The same thing applies to the required holding times for the maximum mold ' ~ `.; , .
.. - , .. . .
., . ,.. : .:- :.
2~3~ ~
: temperature. As a rule of thumb the holding time should be approximately 15 min for each mm thickness of the sintered body.
The following tables reproduce some essential properties of the sintered bodies produced from CPE and FPE in the manner described heretofore:
:
- , ; ; .: - .
-, ". . .~ :.
,, :
2~3~
1. Mechanical Properties (at room temperature, according to DIN-standards) Property UnitCPE FPE
Tensile Strength N/mm287 72 Elongation at tear % 9.4 4.2 Tensile Modulus N/mm22500 2800 Flexural Strength N/mm2125 123 Flexural Modulus N/mm22550 2780 Hardness Rockwell M 104 117 Shore D 88 91 2. Tribological Properties Measured with pin-disk testing apparatus, according to DIN
31680. The disk is of rolling bearing steel with a roughness of Ry=2 ~m.
Unit CPEFPE
.
Coefficient of Friction 0.80.8 Abrasion Factor mm3/Nm 3.5 x 10-6 19.0 x 10-6
DescriPtion of the Prior Art Formed bodies of this kind are known, for example, from European Patent Specifications 64971 and 64972, these being in the form of films produced from a polyester solution by means of a casting process. The polyester described in European Patent Specification 64972 is a polyester based on 1,1-Bis(4-hydroxyphenyl)-1-phenylethane which, as was found, is difficult to process by extrusion or injection molding because of the high process temperatures of 340 to 400C that are required when this is done, whereas the polyester known from European Patent Specification 64971, which is based on 9,9-Bis(4-hydroxyphenyl)fluorene has no melting range at all begins to decompose thermally at a temperature of approximately 400C.
Description of the Invention The object of the present invention is to describe a formed body of the type described in the introduction hereto and which, in contrast to films, can assume a variety of shapes and forms.
This object has been achieved by the shaped body according to the present invention, which is characterized by the fact that it is a sintered body having one or more glass transition points measured by means of DSC, in the range .." . ..
. ~ . ..
.. ~ .. .- -~; - ' 1 ~, -2~3~
~ between 220 and 400C, and a tensile strength, measured ; according to DIN 53455 of greater than 40N/mm , and advan-~ tageously greater than 60N/mm2. It is advantageous that ; the aromatic polyesters that are used are derived from one or more diphenyls of the formula H ~ R ~ OH
, wherein R is a bifunctional hydrocarbon radical contain-ing at least one aromatic or cycloaliphatic ring.
, .
It has been found that with the same type and quality of starting material, relative to cast foils. From this and other facts, which will be discussed subsequently in this specification, one can conclude that the polyester in the sintered body is cross-linked to a certain extent. In a :~ preferred embodiment of the present invention, the sintered body according to the present invention consists essential-ly of an aromatic polyester derived from 9,9-Bis(4-hydroxy-phenyl)fluorene as the diphenyl.
According to another preferred embodiment of the sintered body according to the present invention, this consists essentially of an aromatic polyester derived from 1,1-Bis(4-hydroxyphenyl)-1-phenylethane.
The present invention also refers to an advantageous process for producing the shaped body according to the present invention. This process is characterized in that the aromatic polyester or polyesters in powder form are solidified under pressure; in that the solidified powder is heated slowly to temperatures that are higher than the glass transition point or points of the polyester or poly-esters that are used, this being done while maintaining the pressure; in that the powder mass that has been so com-pressed and which is under pressure is kept at these 2~93~0 temperatures for a specific period of time to form asintered body; and that the body so sintered is then slowly cooled. When this is done, the polyester or polyesters that are in powdered form are advantageously solidified at a pressure of greater than 3,000 N/cm2, although preferably higher than 5,000 N/cm2, such as approximately 10,000 N/cm .
According to advantageous embodiments of the process according to the present invention the slow heating of the compressed polyester powder is effected at a heat-up rate in the range of 1.5 to 4.0C/min and/or the slow cool down of the sintered body is effected at a rate in the range from 0.5 to 2.5C/min.
According to another preferred embodiment of the process according to the present invention, the holding time is in the range of 5-20 min/mm of the mean thickness of the sintered body to be produced, in the direction of the pressure that is applied.
In a further preferred embodiment of the process according to the present invention, the sintered body is cooled at least in part while being acted on by a pressure that is greatly reduced compared to the maximum pressure that is applied.
Some Methods for Carrvinq out the Invention The present invention will be described in greater detail below on the basis of the examples appended hereto.
The sintered bodies produced according to these examples consist of aromatic polyesters as described in European Patent Specifications Nos. 64972 and 64971, namely, . . ~ .
. : !
2~3~
1. Aromatic polyester based on 1,1-Bis(4-hydroxyphenyl)-1-phenylethane and phthalic acid dichloride (iso/tere:
50/50) with a glass transition point of 250C measured by DSC, hereinafter identified as CPE.
2. Aromatic polyester based on 9,9-Bis~4-hydroxy-phenyl)fluorene and phthalic acid dichloride (iso/tere: 50/50) with a glass transition point of 325C measured by DSC, hereinafter identified as FPE.
In order to produce the sintered body one proceeds from the polyesters that are produced in powder form during syn-thesis; these have a mean molecular weight MW of 50,000 to 1,200,000, which corresponds approximately to an inherent viscosity in the range from 0.5 to 3.8 dl/g (measured as described in the above-quoted European Patent Specifica-tions). Of the polyester powder that is produced duringsynthesis, it is the sieve fractions with particle sizes of smaller than 600 ~m, preferably however between 50 and 400 ~m that are used.
Because of their small particle sizes, these powder frac-tions exhibit good sinterability. By eliminating the finest fractions, it has, however, been possible to ensure that the bulk density is not too small, for this would be disadvantageous for the pressing technology.
The production of a sintered body of CPE using a so-called pressure sintering process will be described in greater detail below.
A heated mold is used to produce a plate-shaped sintered body measuring 200 x 220 x 4 mm. After the mold has been preheated to 150C, an appropriate quantity of CPE powder which has been previously dried for several hours at a temperature of 150C in a vacuum oven is placed in the cavity of the lower half of the mold as a filling with a 2~3~
bulk density of 0.35 g/cm3, whereupon the mold is closed by the upper half of the mold, which extends into the mold cavity. The mold is then placed in a press and the CPE
powder is compressed at a pressure of 5,000 N/cm2; the mold is then heated slowly, i.e., at a heating rate of approxi-mately 2C/min, to 270C, which is to say to a temperature above the glass transition point of the CPE powder of 250C, whereupon this temperature is maintained for approx-imately 60 min. Next, the mold is cooled down at a rate of approximately 1C/min to a temperature of 230C; then the pressure is reduced to a low value of approximately 20 N/cm2, that is meant to ensure no more than good contact for thermal loss, whereupon the mold is cooled to 50C, whereupon the sintered body is removed from the mold. The sintered body so obtained has a glass conversion point of 250C, as measured by ASTM D 3418-82, and a density of 1.21 g/cm .
A sintered body of FPE powder can be produced in the same way. Unlike the production of a CPE sintered body, using FPE, this is done at a holding temperature of 330C (higher than the glass transition point of 325C), during cooling the pressure is released at 290C. The FPE sintered body obtained in this way has a glass conversion point of 325C
and a density of 1.22 g/cm3.
The sintered bodies of CPE and FPE have an amber-like colour and are resistant to alcohols, oils, and greases.
As previously stated, polyesters are cross-linked during the sintering process:
A cast foil and a sintered body are produced from CPE and FPE, each with a mean molecular weight MW = approximately 500,000. After the film or sintered body material have been redissolved, the foil material exhibited in molecular ~ , :
..
6 22~3~Q
weight MW of 500,000, whereas that of th~ sintered body material has fallen to a value of MW = 50,000. In contrast - to what could perhaps be assumed, namely, that because of the now lower molecular weight of the sintered body, its resistance to solvent would also be lower, the sintered body has a greater resistance to specific solvents compared to the film material. For example, it was shown that after immersion in carbon tetrachloride for a period of 90 hours in the case of CPE the film absorbs twice as much solvent as the sintered body and, in the case of FPE, the film absorbs 9 times as much.
An improved process for production by sintering is described below. In this process, a mold that is not self-heating, but which can be locked under pressure, is used.
After being filled with the polyester powder (CPE or FPE) the mold is installed in a press where the material is compressed to approximately 10,000 N/cm2 and the mold is locked under pressure, so that even after the mold is taken out of the press the two halves of the mold continue to exert considerable pressure on the material. The mold is then heated slowly in an oven, i.e., at a heating rate of 2/min to 270C (in the case of CPE) or to 330C (in the case of FPE), when, in order to produce a sintered plate that is 4 mm thick, this temperature is maintained for a period of 60 min. Thereafter, the oven heating is switched off and the mold is allowed to cool. After reaching a temperature of 20C beneath the particular glass conversion point, the mold is cooled still more outside the oven, to a temperature of 50C, when the finished sintered body is removed.
In producing sintered bodies it is important to both heat and cool the mold slowly. The permissible heating and cooling rates are smaller the greater the thickness of the sintered body that is to be produced. The same thing applies to the required holding times for the maximum mold ' ~ `.; , .
.. - , .. . .
., . ,.. : .:- :.
2~3~ ~
: temperature. As a rule of thumb the holding time should be approximately 15 min for each mm thickness of the sintered body.
The following tables reproduce some essential properties of the sintered bodies produced from CPE and FPE in the manner described heretofore:
:
- , ; ; .: - .
-, ". . .~ :.
,, :
2~3~
1. Mechanical Properties (at room temperature, according to DIN-standards) Property UnitCPE FPE
Tensile Strength N/mm287 72 Elongation at tear % 9.4 4.2 Tensile Modulus N/mm22500 2800 Flexural Strength N/mm2125 123 Flexural Modulus N/mm22550 2780 Hardness Rockwell M 104 117 Shore D 88 91 2. Tribological Properties Measured with pin-disk testing apparatus, according to DIN
31680. The disk is of rolling bearing steel with a roughness of Ry=2 ~m.
Unit CPEFPE
.
Coefficient of Friction 0.80.8 Abrasion Factor mm3/Nm 3.5 x 10-6 19.0 x 10-6
3. Thermal Properties -Unit CPE FPE Methods max. max.
Glass Transition Point C 250 325 DSC
Temperature of De-flector under Load (Method A) C 217.5 307 TMA
Coefficient of Linear Expansion K-l 75 x 10-6 70 x 10-6 TMA
Thermal Conductivity W/mk 0.19 0.25 .~ :
, ~, ,' .', ;-, ~'.
:
2~5~10
Glass Transition Point C 250 325 DSC
Temperature of De-flector under Load (Method A) C 217.5 307 TMA
Coefficient of Linear Expansion K-l 75 x 10-6 70 x 10-6 TMA
Thermal Conductivity W/mk 0.19 0.25 .~ :
, ~, ,' .', ;-, ~'.
:
2~5~10
4. Electrical Properties Property Unit Treatment CPE FPE
thick- value thick- value ness ness (mm) (mm) -Di-electric Air-Constant conditional at 1 MHz storage C48h/23C
50% 3.68 4.55 water storage D24h/23C 3.03 4.13 Di-electric Dissipa-tion Factor at 1 MHz C48h/23C
50~ 18.7 x 10-3 16.4 x 10-3 water storage D24h/23C 23.2 x 10-3 17.5 x 10-3 Volume Resis-tance at 100 V Ohm C48h/23C
50% 3.25 2 x 1014 3.97 1 x 1ol5
thick- value thick- value ness ness (mm) (mm) -Di-electric Air-Constant conditional at 1 MHz storage C48h/23C
50% 3.68 4.55 water storage D24h/23C 3.03 4.13 Di-electric Dissipa-tion Factor at 1 MHz C48h/23C
50~ 18.7 x 10-3 16.4 x 10-3 water storage D24h/23C 23.2 x 10-3 17.5 x 10-3 Volume Resis-tance at 100 V Ohm C48h/23C
50% 3.25 2 x 1014 3.97 1 x 1ol5
5. Hygroscopic Properties Properties Unit CPE FPE
Water absorption (storage in water 24ht23C) % 0.20 0.25 Hygroscopic Expansion l/%RH - 9.0 x 10-6 , - . ..
~B~03~0
Water absorption (storage in water 24ht23C) % 0.20 0.25 Hygroscopic Expansion l/%RH - 9.0 x 10-6 , - . ..
~B~03~0
6. Burning Properties LOI: CPE 33.5 FPE 40.0 Commercial Utility The sintered bodies described herein are, in general, semi-finished products or preformed parts from which the desired bodies will be produced by way of conventional mechanical machining.
.~:- -.: - , ~
: :.. ::, : :
.~:- -.: - , ~
: :.. ::, : :
Claims (11)
1. A formed body consisting essentially of one or more aromatic polyesters, produced on the basis of di-phenyls and halides of phthalic acid, characterized in that it has a sintered body with one or more glass transition points, measured by means of DSC, in the range between 220 and 400°C, and a tensile strength, measured according to DIN 53455 which is greater than 40 N/mm2, and advantageously greater than 60 N/mm2, in particular, of greater than 70 N/mm2.
2. A body according to claim 1, characterized in that the aromatic polyester or polyesters are derived from one or more diphenyls of the formula
3. A body as defined in claim 2, characterized in that it consists essentially of an aromatic polyester derived from 9,9-Bis(4-hydroxyphenyl)fluorene as the diphenyl.
4. A body as defined in claim 2, characterized in that it consists essentially of an aromatic polyester derived from 1,1-Bis(4-hydroxyphenyl)-1-phenylethane and has a tensile strength, measured according to DIN 53455, of greater than 50 N/mm2, and in particular greater than 70 N/mm2.
5. A process for producing a formed body as defined in one of the claims 1 to 4, characterized that the aro-matic polyester or polyesters in powder form are com-pressed under pressure; in that while the pressure is being maintained, the compressed powder is heated slowly to temperatures that are higher than the glass transition point or points of the polyester or polyesters that are used; in that the powder mass that is so compressed and under pressure is maintained at these temperatures for a longer holding time in order to form a sintered body; and in that the body so sintered is slowly cooled.
6. A process as defined in claim 5, characterized in that the polyester or polyesters in powder form are com-pressed at a pressure of greater than 3,000 N/cm2, in particular, however, of greater than 5,000 N/cm2.
7. A process as defined in claim 6, characterized in that the powdered polyester or polyesters are compressed at a pressure of approximately 10,000 N/cm2.
8. A process as defined in one of the claims 5 to 7, characterized in that the slow heating of the com-pressed polyester powder is effected at a heating rate in the range of 1.5 to 4.0°C/min.
9. A process as defined in one of the claims 5 to 8, characterized in that the slow cooling of the sintered body is effected at a rate in the range of 0.5 to 2.5°C/min.
10. A process as defined in one of the claims 5 to 9, characterized in that the holding time is in the range of 5-20 min/mm of the mean thickness of the sintered body to be produced determined in the direction of the pressure that is applied.
11. A process as defined in one of the claims 5 to 10, characterized in that the cooling of the sintered body is effected at least in part under the effect of a pressure that is greatly reduced compared to the maximum pressure that is applied.
Applications Claiming Priority (5)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| ATA221/90 | 1990-02-02 | ||
| AT0022190A AT395431B (en) | 1990-02-02 | 1990-02-02 | SHAPED BODY MADE OF AROMATIC POLYESTERS |
| US539,082 | 1990-06-15 | ||
| US07/539,082 US5102974A (en) | 1990-02-02 | 1990-06-15 | Formed, sintered body comprising one or more aromatic polyesters |
| PCT/AT1991/000017 WO1991011312A1 (en) | 1990-02-02 | 1991-02-04 | Aromatic polyester moulded compacts |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2050310A1 true CA2050310A1 (en) | 1991-08-03 |
Family
ID=25591924
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002050310A Abandoned CA2050310A1 (en) | 1990-02-02 | 1991-02-04 | Aromatic polyester moulded compacts |
Country Status (4)
| Country | Link |
|---|---|
| EP (1) | EP0471803A1 (en) |
| JP (1) | JPH04504546A (en) |
| CA (1) | CA2050310A1 (en) |
| WO (1) | WO1991011312A1 (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| AT395431B (en) * | 1990-02-02 | 1992-12-28 | Isonova Tech Innovat Gmbh | SHAPED BODY MADE OF AROMATIC POLYESTERS |
| EP0513252A1 (en) * | 1990-08-28 | 1992-11-19 | Isonova Technische Innovationen Ges.M.B.H. | High purity aromatic polyester, a film and other products and devices containing such polyester as well as a process for preparing such film |
| CA2079795A1 (en) * | 1991-02-04 | 1992-08-05 | Peter Fialla | Moulded aromatic-polyester article |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3558550A (en) * | 1967-02-07 | 1971-01-26 | Montedison Spa | Sinterings of polytetrafluoroethylene loaded with titanium and the preparation thereof |
| BE789542A (en) * | 1971-10-01 | 1973-03-29 | Carborundum Co | PRODUCTION OF INFUSIBLE AND FORMABLE PARA-OXYBENZOYL POLYESTER |
| US4011293A (en) * | 1973-08-21 | 1977-03-08 | E. I. Du Pont De Nemours And Company | Toughened linear aromatic polymers |
| US3980749A (en) * | 1973-08-31 | 1976-09-14 | The Carborundum Company | Partially crosslinked linear aromatic polyesters |
| ATE33027T1 (en) * | 1981-05-07 | 1988-04-15 | Isovolta | HIGH MOLECULAR MOLECULAR AROMATIC POLYESTER, PROCESS FOR MANUFACTURE OF FILM FROM SUCH POLYESTER AND FOIL FROM SUCH POLYESTER, ELECTRICAL CONDUCTOR WITH INSULATION FROM SUCH POLYESTER AND METHOD FOR MANUFACTURE OF SUCH INSULATION. |
-
1991
- 1991-02-04 CA CA002050310A patent/CA2050310A1/en not_active Abandoned
- 1991-02-04 WO PCT/AT1991/000017 patent/WO1991011312A1/en not_active Application Discontinuation
- 1991-02-04 EP EP91903442A patent/EP0471803A1/en not_active Withdrawn
- 1991-02-04 JP JP3503625A patent/JPH04504546A/en active Pending
Also Published As
| Publication number | Publication date |
|---|---|
| WO1991011312A1 (en) | 1991-08-08 |
| EP0471803A1 (en) | 1992-02-26 |
| JPH04504546A (en) | 1992-08-13 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FZDE | Discontinued |