Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Processes of preparing a desired or intentional composition...
Reexamination Certificate
2000-04-06
2001-09-25
Hoke, Veronica P. (Department: 1714)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Processes of preparing a desired or intentional composition...
C524S101000, C524S445000, C524S446000, C524S447000
Reexamination Certificate
active
06294599
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a highly-rigid, flame-resistant polyamide composite material that exhibits less warp, and a superior performance with respect to molding-shrinkage, anisotropy, dimensional stability, flame-resistance, mechanical strength, heat-resistance, and improvement over problems associated with bleed-out, and mold deposit. The composite material according to the present invention may be applied to various uses, for example, in materials for electric and electronic parts, automobile parts, materials for house appliances, mechanical parts, and the like. The present application is based on the specification of Japanese Patent Application (First Publication No. Hei 10-224820), the contents of which are included in the present application.
BACKGROUND ART
Flame-resistant polyamide resins are widely used in material for electric and electronic parts, and automobile parts due to their superior mechanical properties, heat-resistance, and flame-resistance.
On the other hand, in order to improve performance with respect to mechanical strength and heat-resistance, fibrous fillers such as glass fiber, carbon fiber, whisker, and the like, are often mixed therein. However, such fibrous fillers creates problems such as warp, and an unfavorable appearance for molded products, and thus a method for using a plane filler such as talc, and the like, along with the fibrous filler, has been proposed in order to solve the aforementioned problems.
However, fillers which are used to impart the above improvements decrease the flame-resistance of the composite material, and thus, a large amount of flame retarder is required for the flame-resistant effects, creating problems associated with bleed-out and mold deposit of molded products.
Accordingly, a highly-rigid, flame-resistant polyamide composite material that exhibits a superior performance with respect to mechanical strength and heat-resistance while maintaining its flame-resistance property, wherein problems associated with warp, dimensional stability, bleed-out, and mold deposit are improved, is highly desired.
DISCLOSURE OF THE INVENTION
As a result of extensive research to solve the aforementioned problems, the inventors of the present invention have found that it is possible to solve the aforementioned problems by means of using a specific silicate complex, and the inventors have completed the present invention.
That is, the highly-rigid, flame-resistant polyamide composite material according to the present invention is characterized in comprising (a) polyamide resin, (b) silicate complex comprising a layered silicate and triazine compound, (c) fibrous reinforcement, and (d) flame retarder.
Such highly-rigid, flame-resistant polyamide composite material exhibits less warp, and a superior performance in molding-shrinkage, anisotropy, dimensional stability, flame-resistance, mechanical strength, and heat-resistance, and also improves the problem associated with bleed-out and mold deposit. In addition, it also provides a favorable appearance and processing properties.
BEST MODES FOR CARRYING OUT THE INVENTION
The polyamide resin (a) used in the present invention is a polymer comprising repeating units of an acid amide (—CONH—). Concrete examples of the polyamide resin may include polylactams such as polyamide 6, polyamide 11, polyamide 12, and the like; polyamides comprising a dicarboxylic acid and diamine such as polyamide 66, polyamide 610, polyamide 612, polyamide 46, and the like; copolyamides such as polyamide 6-66, polyamide 6-610, and the like; polyamide 6-6T (wherein T represents a terephthalic acid component); and semi-aromatic polyamides comprising an aromatic dicarboxylic acid such as isophthalic acid, and methaxylylene diamine or aliphatic diamine. These polyamide resins may be used alone or in combinations of two or more. Additionally, these polyamide resins are not constrained by their relative viscosity, type of terminal group, or concentration.
The silicate complex (b) used in the present invention is obtained by means of inserting or absorbing triazine compounds between layers of a layered silicate.
The layered silicate, used in the present invention, varies in its chemical composition and crystal structure, and is not established in terms of classification and nomenclature. The layered silicate used herein is characterized by its particular layered crystal, and belongs to the philo-silicates in mineralogy. In particular, examples of such may include a 2:1 type philo-silicate comprising two tetrahedral layers and one octahedral layer; and a 1:1 type philo-silicate comprising one tetrahedral layer and one octahedral layer. Representative minerals of the 2:1 type philo-silicate include smectite, vermiculite, mica, and chlorites. Representative minerals of the 1:1 type philo-silicate include kaolin, serpentine, and the like. Examples of the smectite group include saponite, hectorite, sauconite, montmorillonite, beidellite, nontronite, stevensite, and the like. Examples of the vermiculite group include trioctahedral vermiculite, dioctahedral vermiculite, and the like. Examples of the mica group include phlogopite, biotite, lepidolite, muscovite, palagonite, chlorite, margarite, taeniolite, tetrasilicic mica, and the like. These philo-silicates may be either naturally produced or synthetically produced according to a hydrothermal reaction method, melting method, or solid phase method.
The triazine compound, used in the present invention, is a compound that specifically functions as a flame retarder for polyamide. Examples of the triazine compound may include a melamine compound, cyanuric acid compound, melamine cyanurate compound, derivatives thereof, and the like.
The melamine compound is a compound represented by the following chemical formula. In the chemical formula, R
1
and R
2
may represent either an identical or different entity, such as a hydrogen atom, methyl group, ethyl group, ethylene group, phenyl group, benzyl group, halogenophenyl group, or the like. Concrete examples of the melamine compound may include melamine, N-ethylene melamine, N,N′,N″-triphenyl melamine, and the like.
The cyanuric acid compound is a compound represented by the following chemical formula. In the chemical formula, R
3
may represent either an identical or different entity, such as a hydrogen atom or lower alkyl group. R
3
is preferably a hydrogen atom in the present invention. Concrete examples of the cyanuric acid compound may include cyanuric acid, isocyanuric acid, trimethyl cyanurate, trismethyl isocyanurate, triethyl cyanurate, trisethyl isocyanurate, tri(n-propyl) cyanurate, tris(n-propyl) isocyanurate, diethyl cyanurate, N,N′-diethyl isocyanurate, methyl cyanurate, methyl isocyanurate, and the like.
The aforementioned melamine cyanurate compound is a reactant comprising equivalent molar amounts of a melamine compound and cyanuric acid compound, and can be produced, for example, by means of mixing a melamine aqueous solution and cyanuric acid aqueous solution to promote the reaction while stirring at a temperature of approximately 90~100° C., and filtrating the resultant precipitate. The resultant product is a white solid, which is used in the form of a ground powder. Alternatively, a commercially available product may be used in its original form or in the form of a ground powder.
Examples of the triazine compound derivative may include a mixture of the aforementioned triazine compound and a Lewis acid compound. The Lewis acid is an electron pair acceptor, examples of which may include hydroacids such as hydrochloric acid and hydrogen sulfide; oxoacids such as sulfuric acid, nitric acid, acetic acid, phosphoric acid, and the like; thio acids such as ethylxanthogenic acid; alkyl halide chlorides; acid halides; and the like.
The blending amount of the lewis acid is generally 0.01~3 mol, and preferably 0.1~2 mol, per 1 mol of the triazine compound.
The blending amount of the triazine compound is generally 0.1~10 times the equivalent amount, and preferably 0.3~5 times the equivalent a
Ebata Tsuguo
Inoue Hirofumi
Noguchi Masayuki
Tamura Kenji
Hoke Veronica P.
Showa Denko K.K.
Sughrue Mion Zinn Macpeak & Seas, PLLC
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