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
2000-08-11
2001-11-27
Woodward, Ana (Department: 1711)
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...
C523S209000, C523S216000, C523S443000, C524S442000, C524S447000, C524S449000
Reexamination Certificate
active
06323272
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to polyamide resin compositions with good dimension stability during absorption and good mechanical properties.
SUMMARY OF THE INVENTION
Polyamide resis is employed widely, such as for various industrial parts. However, due to high water-absorption of the polyamide resins, there are disadvantages, e.g. reduction of strength due to water absorption and dimensional changes of molded articles.
To modify this behavior, adding polyolefin resins with low water absorption has been proposed. JP Patent Application Disclosure No. 11-181277 discloses polyamide resin compositions with improved dimensional stability during water absorption wherein lipophilic intercalation compounds of swelling silicate treated with tetraalkyl ammonium compounds are employed together with polyolefin to improve the dimensional stability during water absorption.
In the former method, a large amount of polyolefin resin is required to suppress dimensional changes due to water absorption, and consequently a reduction in strength and stiffness is unavoidable. In the latter method, lipophilic intercalation compounds are finely dispersed to suppress water absorption, and to improve dimensional stability, but the effect is not sufficient.
In view of said circumstances, the present invention has been made to provide polyamide resin compositions with good mechanical properties and dimensional stability during water absorption.
These and other objects, advantages and features of the invention will be set forth in the detailed description which follows.
DETAILED DESCRIPTION OF THE INVENTION
The present inventors have investigated the matter and found the triazine-containing layered silicates exhibit a larger reinforcing effect to polyamide resins in comparison with layered silicate treated with tetraalkyl ammonium compounds. They further found that mechanical properties and dimensional stability of polyamide resin compositions are considerably improved by the use of triazine-containing layered silicates and a certain polyolefin resin.
The present invention provides polyamide resin compositions, comprising 100 parts by weight of resin contents composed of (A) 60 to 98% by weight of polyamide resins, (B) 40 to 2% by weight of polyolefin resins having dicarboxylic acid anhydride groups, as well as (C) 0.3 to 30 parts by weight of derivatives with at least one positive charge.
The polyamide resins (A) of the present invention are in general polymer compositions having acid amide bond (—CONH—) as repetition units, and are not particularly limited. As representative examples, there are polyamides from lactams, such as polyamide 6, polyamide 12; polyamide 11 from amino undecanoic acid; polyamides from dicarboxylic acid and diamine, such as polyamide 66, polyamide 612, polyamide 46; copolyamides, such as polyamide 6-66, polyamide 6-610; semi-aromatic polyamides, such as polyamide 6T, polyamide 61, polyamide 6T/61, polyamide MXD6, obtained from aromatic dicarboxylic acids, such as terephthalic acid (%), isophthalic acid (I), and aliphatic diamines, or from aromatic diamines, such as m-xylylene diamine (MXD), and liphatic dicarboxylic acid. One or more kinds of polyamide resins may be used.
Examples for polyolefin resin having dicarboxylic acid anhydride group (B) according to the present invention, are copolymers of olefin and unsaturated dicarboxylic acid anhydride, or modified polyolefins wherein polyolefin is grated with unsaturated dicarboxylic acid anhydride.
Olefms employed for copolymers of olefins and unsaturated dicarboxylic acid anhydrides are not restricted. They may be ethylene, propylene, 1-butene, 3-methyl-1-butene, 1-hexene, 4-methyl-1-pentene, etc. As examples of unsaturated dicarboxylic acid anhydrides, there are maleic anhydride, itaconic anhydride, citraconic anhydride. Third components may be copolymerized with the copolymer. As concrete examples of the third components, there are unsaturated carboxylic acid esters, such as methyl(meth)acrylate, ethyl(meth)acrylate, butyl(meth)acrylate, 2-ethylhexyl(meth)acrylate. The copolymerisation proportion of said saturated dicarboxylic acid anhydride is normally 0.5 to 5% by weight, preferably 1.0 to 4% by weight. The copolymerisation proportion of the third component is at most 20% by weight, preferably 15% by weight or less.
As modified polyolefin wherein polyolefin is grafted with unsaturated dicarboxylic acid anhydride there are the ones obtained by that homopolymer or copolymer of ethylene of propylene is grat-polymerised with dicarboxylic acid anhydride. The graft content of unsaturated dicarboxylic acid anhydride is preferably 0.01 to 5% by weight, more preferably 0.05 to 4% by weight. As grafting methods, known methods, e.g. melting and kneading by an extruder in the presence of organic peroxide, are employable.
The proportion of component (A) to the combined total of said components (A) and (B), is in the range of 60 to 98% by weight, preferably 65 to 95% by weight, more preferably 65 to 90% by weight. With less than 60% by weight of component (A), the molding process ability is reduced. On the other hand, if the proportion is exceeding 98% by weight, change in dimensions become larger.
The present triazine-containing layered silicate is available from layered silicate and triazine-compound derivatives. The triazine compound derivatives are available by acid-base reaction of triazine compounds and Lewis acid compounds.
A large variety of layered silicates partly of different chemical composition and crystal structure is known. Characteristic of the layered silicates herein is the lamellar crystal structure. Mineralogically they belong to the phyllosilicates. In particular, there are 2:1 phyllosilicates made of two tetrahedral layers and one octahedral layer, and 1:1 phyllosilicates made of one tetrahedral layer and one octahedral layer. Representative minerals of 2:1 phyllosilicates, are smectite, vermiculite, mica, chlorites, and of 1:1 phyllosillictes, kaolin, serpentine, etc. In the smectite group there are saponite, hectorite, sauconite, montinorillonite, beidellite, nontronite, stevensite, etc., and in the vermiculite group, trioctahedral vermiculite, dioctahedral vermiculite, etc. In the mica group are, compositions, such as phlogopite, biotite, lepidlite, muscovite, paragonite, chlorite, margarite, taeniolite, tetrasilicic ica, etc. Those phyllosilicates may be natural products or synthetic ones prepared by means of the hydrothermal method, the melting method, the solid phase method, etc. The layered silicates usable in this invention are not limited to these examples. Tirazine compounds are compounds with six-membered rings containing three nitrogen atoms; preferably are 1,3,5-triazine compounds, specifically melamines, such as melamine, N-ethylenemelamine, N,N′,N″-triphenyl melamine, cynuric acids, such as cyanuric acid, isocyanuric acid, trimethylcyanurate, tri(n-propyl(cyanurate, tris)n-propyl)isocyanuarte, diethylcyanuarte, N,N′-diethylisocyanurate, methylcyanurate, methylisocyanuarte, etc. Melamine cyanurates are composed of one equivalent each of melamine compounds and cyanuric acid compounds. The melamine cyanurate compounds are produced for example by than an aqueous solution of melamine and an aqueous solution of cyanuric acid are mixed and reacted under stirring at a temperature of ca. 90 to 10° C.
Lewis acid compounds are electron pair acceptors, e.g. hydroacids, such as hydrochloric acid and hydrogen sulfide, oxo acids, such as sulphuric acid, nitric acid, acetic acid and phosphoric acid, thioacids, such as ethylxantogen acid, etc., alkylhalides an acid halides.
As methods for obtaining the present triazine compound derivatives with positive charge, there are exemplified methods wherein traizine compounds are dissolved in water of alcohol, subsequently, Lewis acid is added thereto and stirring is effected. The incorporation amount of Lewis acid is normally 0.01 to 3 mol, more preferably 0.1 to 2 mol vis-a-vis 1 mol of triazine compounds. The generated triazine comp
Ebata Tsuguo
Inoue Hirofumi
Nakamura Jun-ichi
Noguchi Masayuki
Tamura Kenji
Banner & Witcoff , Ltd.
Ems-Chemie AG
Woodward Ana
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