Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – At least one aryl ring which is part of a fused or bridged...
Reexamination Certificate
1999-12-20
2001-08-21
Yoon, Tae H. (Department: 1714)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
At least one aryl ring which is part of a fused or bridged...
C524S538000, C525S432000, C528S335000, C528S346000
Reexamination Certificate
active
06277911
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to transparent, colorless and amorphous polyamides and blends or alloys thereof with homopolyamides, and molded articles made therefrom.
BACKGROUND OF THE INVENTION
European patents EP 50 742 and EP 69 700, and U.S. Pat. Nos. 2,696,482; 3,597,400; 4,207,411; and 4,369,305, all describe amorphous polyamides made from aliphatic diamines and/or 4,4′-diaminocyclohexylmethane (PCAM) and aromatic dicarboxylic acids. Unfortunately, these polyamides have inadequate tenacity and transparency, and they are not colorless.
Polyamides described in U.S. Pat. No. 2,512,606 and published German Patent Disclosure Application DE-OS 29 34 541, which are made from aliphatic dicarboxylic acids and unsubstituted cycloaliphatic diamines with a high proportion of trans-trans isomer are inadequately resistant to stress cracking in boiling water and alcohols to be commercially useful. Additionally, some of these polymers are cloudy.
Polyamides disclosed in German Patent Disclosure DE 43 10 970 require an especially high proportion of trans-trans isomer of from 35 to 60% of the 4,4′-diaminodicyclohexylmethane, which is attained only by means of special reaction conditions, including with expensive distillative fractionation in producing the diamine. These diamines are thus considerably expensive. They are commercially available under the trade names PCAM 50(R) (DuPont, Wilmington, Del.) and Wondamin(R) (New Japan chemical Corporation, Osaka). Dicycan(R), from BASF, an unsubstituted bis(4-aminocyclohexyl)methane, has similar high trans-trans isomer proportions. While these diamines can be used to prepared polyamides with satisfactory tenacity, their resistance to bending stress and their lack of dimensional stability under elevated temperatures makes shaped articles made form them inadequate for certain applications, such as filter bowls for use under high temperature ranges.
German Patent Disclosure DE 15 95 354 describes a process for preparing crystal-clear polyamides from dicarboxylic acids and a defined isomer mixture of bis(aminocyclohexyl)-propane, which can contain up to 80% caprolactam.
However, this patent expressly mentions that those polyamides that contain dodecanoic acid as the carboxylic acid are subject to clouding.
German Patent Disclosure DE 37 17 928 covers transparent copolyamides of preferably aromatic dicarboxylic acids containing the isomers, no longer available, of bis(4-amino-3-methyl-5-ethylcyclohexyl)methane, which have insufficiently high Tg values. German Patent Disclosure DE 37 28 334 discloses blends of copolyamides of aromatic dicarboxylic acids and a mixture of hexamethylene diamine and PACM. Although these latter copolyamides have modified impact strength, they again have low Tg values.
SUMMARY OF THE INVENTION
It is an object of the present invention to overcome the aforesaid deficiencies in the prior art.
It is another object of the present invention to provide polyamide molding compositions which are transparent, colorless, and amorphous.
It is another object of the invention to provide polyamide molding compositions which have sufficient resistance to stress and dimensional stability under elevated temperatures.
According to the present invention, transparent, colorless, amorphous copolyamides and their blends or alloys are provided wherein the copolyamides are made of:
(A) at least one alkyl-substituted cycloaliphatic diamine having from 14 to 22 carbon atoms; and
at least one unbranched aliphatic dicarboxylic acid having from 7 to 14 carbon atoms, together with at least one aromatic dicarboxylic acid wherein said at least one aromatic dicarboxylic acid is present in an amount of no more than 20 mol %;
wherein said copolyamide or blend or alloy optionally contains processing and/or usage dictated additives, and wherein said copolyamides have relative solution viscosity of more than 1.6 and wherein said further polyamides are selected from the group consisting of homopolyamides and transparent copolyamides. The present invention is also directed to and molded articles made therefrom.
In particular, the copolyamides, as well as blends and alloys, of at least one aliphatic homopolyamide or amorphous copolyamide with the copolyamides, are those in which preferably long-chain aliphatic monomer units are combined with cycloaliphatic monomer units having at least one cyclohexane ring. As a result of this combination, the copolyamides so produced exhibit extremely high alternating bending strength as well as high tenacity, high rigidity, high resistance to heat distortion under elevated temperatures, and good solvent resistance.
These transparent, amorphous, colorless copolyamides are made substantially from (a) alkyl-substituted cycloaliphatic diamines, preferably those with from 14 to 22 carbon atoms, which are combined with long-chain unbranched aliphatic dicarboxylic acids that have from 7 to 36 carbon atoms, preferably from 8 to 14 carbon atoms, whereby some of the long-chain unbranched aliphatic dicarboxylic acids are replaced with small proportions of aromatic dicarboxylic acids, preferably a maximum of 20 mol % and especially preferably a maximum of 10 mol % thereof.
The term alkyl-substituted cycloaliphatic diamines is understood to mean those diamines that have one or more alkyl substituents, such as methyl, ethyl, propyl, and isobutyl radicals, on at least one cyclohexane ring.
Surprisingly, it has been found that, especially, the transparent copolyamides made up of octanedioic acid, nonanedioic acid, decanedioic acid, undecanedioic acid, or dodecanedioic acid and said cyclic diamines, alone or in blends or mixtures or alloys with further polyamides, are suitable for producing molded articles that are highly ductile, extraordinarily resistant to alternate bending, and which are nevertheless rigid and have high resistance to heat distortion and resistance to stress cracking in alcohol, ketones, and hot water.
Other preferred colyamides are prepared from at least one diamine selected from the group consisting of:
2,2-bis-(4-aminocyclohexyl)-propane
2,6-bis-(aminomethyl)-norbornane
3-aminomethyl-3,5,5-trimethylcyclohexylamine
bis-(4-aminomethylcyclohexyl)
bis-(4-aminocyclohexyl)methane
diaminomethyl-tricyclodecane
1,3-bis(aminomethyl)-dicyclohexane
bis-(4-amino-3methyl-2-ethylcyclohexyl)methane
bis-(4-amino-3,5-diethylcyclohexyl)-methane
2,2-bis-(3-methyl-4-aminocyclohexyl)-propane
4,4′-bis(aminomethyl)-dicyclohexane
Especially preferred are those copolyamides in which the at least one long chain unbranched aliphatic dicarboxylic acid is replaced by up to about 20 mol % of at least one aromatic dicarboxylic acid.
The resulting copolyamides exhibit advantageously high Tg values, high tensile strengths, and high tensile E-moduli.
Polyamides according to the present invention can be prepared by conventional processes under pressure in autoclaves or in reaction extruders at temperatures that are preferably above 260° C.
Blends or alloys with further homopolyamides or amorphous copolyamides are prepared by conventional processes known to those skilled in the art.
Further homopolyamides advantageously used in the present invention are preferably selected from the group consisting of polyamide 69, polyamide 610, polyamide 612, polyamide 912, polyamide 1212, polyamide 11, polyamide 12, polyamide 3,31-dimethyl-4,4′-diaminocyclohexylmethane 12, polyamide bis-(3-methyl-4-aminocyclohexyl)methane isophthalic acid, polyamide bis-(3-methyl-4-aminocyclohexyl)methane terephthalic acid, polyamide bis-(p-aminocylohexyl)methane 12, polyamide bis-(p-aminocylohexyl)methane isophthalic acid, polyamide bis-(p-aminocylohexyl)methane terephthalic acid, polyamide 2,2-bis-(p-aminocyclohexyl)propane 12, polyamide 2,2-bis-(p-aminocyclohexyl)propane isophthalic acid, polyamide 2,2-bis(p-aminocyclohexyl)propane terephthalic acid, polyamide isophorone diamine 12, polyamide isophorone diamine terephthalic acid, polyamide diaminomethylnorbornane 12 and polyamide diaminomethyl-tricyclodecane 12; or at least one further amorp
Browdy and Neimark
Ems - Inventa AG
Yoon Tae H.
LandOfFree
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