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...
Patent
1986-07-15
1988-08-02
Bleutge, John C.
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...
524261, 524264, 524265, 524266, 524267, 524268, 524538, 524606, 525431, C08K 554, C08L 8306
Patent
active
047614455
DESCRIPTION:
BRIEF SUMMARY
DETAILED DESCRIPTION OF THE INVENTION
1. Scope of industrial application
The subject invention relates to polytetramethylene adipamide resin compositions superior in sliding characteristics.
2. Description of prior art
Being fundamentally superior in friction and wear characteristics, polyamides are regarded as being suitable for manufacturing gears and bearings and other sliding parts. The wear depends on the pressures applied to the sliding surface, the sliding speeds, the atmospheric conditions, the temperature and so forth.
For practical applications resistance to increasingly severe conditions are demanded and polyamide materials have been modified for this. Hitherto polyamide compositions obtained by adding molybdenum disulfide, polyethylene, fluoric polymers and silicon oils to polyamides have generally been used for this purpose.
However it has been observed that in the case of the ordinary straight-chain polyamides e.g. polycaprolactam (nylon-6) or polyhexamethylene adipamide (nylon-6.6), the silicon oil is insufficiently accepted by the material and causes considerable bleed-out to the surface of moldings that are obtained from compositions of these polyamides with silicon oils. Because of this bleeding-out effect the moldings become inferior in surface appearance.
However for obtaining good sliding properties it is necessary to have the silicon oil present in appreciable amounts. Further the mechanical properties of the polyamide composition should remain high to be usefull under severe conditions. One has tried to solve this problem in essentially two manners. In the first solution one uses mixtures of lubricants, in which silicon oil is present in low concentrations. For instance a mixture of 2 percent silicon oil and 18 percent by weight polytetra-fluoroethylene in 80 percent by weight polyamide is used in U.S. Pat. No. 4,428,589. Secondly one has tried to incorporate in the polyamide molding an inorganic highly porous material which functions as a carrier for the silicon oil. See for instance JP-A-57174345.
However these compositions have the disadvantage of being difficult to process, or need expensive materials or the physical properties of the polyamide composition have been negatively effected.
The object of the invention is therefore to produce a polyamide/silicon oil composition of superior sliding properties and mechanical strength with good surface appearance.
It has been found that polytetramethylene adipamide (nylon-4.6) shows a surprisingly high affinity for silicon oils, so that even at high concentrations of the silicon-oils no unacceptable level of bleeding is observed. Further the resin composition shows superior properties over present materials to make a highly practicable material for various kinds of gears and bearings. Especially the combination of high heat resistance and rigidity of nylon 4.6 and the vast improvement in sliding performance due to the presence of a relatively high concentration of silicon oil produces these synergistic effects.
Therefore the polyamide resin composition according to the subject invention is obtainable by blending 2 to 20 parts by weight of silicon oil with 100 parts by weight of a polyamide with tetramethylene adipamide as main component.
The polyamides according to the subject invention are copolymers and mixtures of polyamides containing polytetramethyleneadipamide and tetramethylene adipamide as main components. In principle there exist no limitations concerning the copolymer and mixture components, so that all known amide-forming compounds can be chosen.
Representative among the former are 6-aminocaproic, 11-aminoundecanic, 12-aminododecanic, paraminomethylbenzoic and other amino acids; .epsilon.-caprolactam, .omega.-laurolactam and other lactams; hexamethylenediamine, undecamethylenediamine, dodecamethylenediamine, 2.2.4-/2,2,4-trimethylhexamethylenediamine, 5-methylnonamethylenediamine, methaxylirenediamine, paraxylirerediamine 1,3- and 1,4-bis(aminomethyl)cyclohexanes, 1-amino-3-aminomethyl-3,5,5-trimethylcyclohexane, bis(4-aminoc
REFERENCES:
patent: 4428589 (1984-01-01), Reinsmo
Chemical Abstracts, vol. 80, No. 23, 3 Jun. 1974, Kashio Junzo et al., "Polyamide Powdery Composition for Coating", p. 98, abs. no. 122569q & JP, A, 7328337 (Toray Industries), Aug. 31, 1973.
Chemical Abstracts, vol. 80, No. 10, 11 Mar. 1974, Ohba Tasaaki, "Holding by Polymerization of Lactams", pp. 30, 31, abs. no. 48814x & JP, A, 7251479 (Teijin), Dec. 31, 1972.
Bleutge John C.
Stamicarbon B.V.
Woodward David W.
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