Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Mixing of two or more solid polymers; mixing of solid...
Reexamination Certificate
2001-01-10
2003-11-11
Seidleck, James J. (Department: 1711)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Mixing of two or more solid polymers; mixing of solid...
C525S436000, C428S473500, C360S003000
Reexamination Certificate
active
06646060
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a thermoplastic resin composition composed mainly of a crystalline polyamide and a thermoplastic polyester. More particularly it relates to a polyamide/polyester-based thermoplastic resin composition having excellent heat-resistance, mechanical characteristics such as mechanical strength and elastic modulus and/or moldability such as the fluidity in molding and usable as a molded article such as an electronic part suitable for surface mounting and a film.
BACKGROUND ARTS
A surface-mounting process using a surface-mounting technology (SMT) is being spreading in the field of electronic parts. Furthermore, improvement on the mechanical strength, moldability and heat-resistance has been required for a resin for surface-mounting electronic parts because of the miniaturizing and thinning tendency of electronic parts and the exposure of the material for electronic part such as connector to severe temperature condition compared with conventional mounting process by the adoption of soldering process.
To meet the requirement, the application of a polyamide resin such as nylon 6 resin and nylon 66 resin; a semi-aromatic polyester resin such as polyethylene terephthalate (PET) and polybutylene terephthalate (PBT); a polyphenylene sulfide resin and an aromatic polyamide resin has been investigated.
However, these resins have excellent mechanical strength and fluidity but poor heat-resistance or excellent heat-resistance but poor mechanical strength and fluidity and, accordingly, there is considerable restriction on the industrial use of these resins.
In regard to heat-resistance, it is known that an amorphous polyether imide (e.g. ULTEM100, product of GE) is compatible with PET to increase the glass transition temperature (Tg) of PET (e.g. specifications of U.S. Pat. No. 4,141,927; JP-B 3-58384; J. Appl. Polym. Sci. (1993) vol.48, p.
935
; Polymer Bulletin (1994) vol.33, p.113; Macromolecules (1995) vol.128 2845), etc.). There are similar reports on the polymer blend of the amorphous polyether imide and PBT (e.g. specification of U.S. Pat. No. 4,141,927). Similar reports are also found on the polymer blend of the amorphous polyether imide and polyethylene-2,6-naphthalenedicarboxylate (PEN) (e.g. ANTEC 1995 p.1453-1458; Polymer Vol.36, Number 23 1995 p.4449; RESEARCH DISCLOSURE 1987 p.677; JP-A 7-228761).
However, the blending of the above-mentioned ULTEM and a polyester is generally difficult owing to the large difference between their melt viscosity values reflecting their Tg difference. Accordingly, it is necessary to increase the mixing efficiency by the use of an extruder, etc., and mix both resins at a high temperature for a long period to achieve homogeneous mixing of both resins. Such method has problems of e.g. causing thermal deterioration of the polymer.
Specification of JP-A 51-143060 discloses a polymer blend containing a specific polyether imide and a specific polyester. The polymer blend has a melt viscosity lower than that of polyether imide, however, a slight improvement on the mechanical strength is found only at a polyether imide content of 90% by weight or more and the improving effect is insufficient.
Specification of JP-A 59-37161 discloses a heat-resistant polyester container formed of a non-oriented amorphous sheet made of a resin composition composed of 60 to 99% by weight of PET and 40 to 1% by weight of a polyether imide. The polyether imide disclosed in the above specification is same as the one described in the specification of the above-mentioned JP-A 51-143060, and there is no description on the improvement of mechanical properties.
A polyimide composed of the monomer unit of 3,3′,4,4′-benzophenonetetracarboxylic acid dianhydride and the monomer unit of 1,4-diaminobutane and a polymer blend of the polyimide and a thermoplastic polymer including PET and PBT are disclosed in the specification of JP-A 6-49206, however, there is no description on the improvement of the mechanical strength of such polymer blend. The Tg of the polymer blend is increased owing to high Tg of ULTEM1000, and the molding becomes difficult owing to the increased melt viscosity. The produced molded article is brittle and there is no improvement on the delamination trouble of a film caused by bending the film to apply a stress.
A resin composition containing a copolymerized polyester composed of 4,4′-biphenyldicarboxylic acid as the acid component and 1,4-cyclohexane dimethanol and ethylene glycol as the glycol component in combination with a modifier (for example, ULTEM of GE) is disclosed in the specification of U.S. Pat. No. 5,057,595.
The specification of U.S. Pat. No. 5,037,946 discloses a resin composition containing a copolymerized polyester composed of 4,4′-biphenyldicarboxylic acid as the acid component and 1,6-hexanediol and ethylene glycol as the glycol component in combination with a modifier similar to the above.
The specification of JP-A 10-330604 discloses that the crystallinity, melt-formability, weather resistance and delamination resistance can be improved by blending a polyimide having low-Tg and composed of specific repeating units to a polyalkylene naphthalate, however, the improvement is insufficient because there is no improvement of the mechanical properties.
Furthermore, all of the descriptions of these specifications of JP-A 51-143060, JP-A 59-37161, JP-A 6-49206, U.S. Pat. No. 5,057,595, U.S. Pat. No. 5,037,946 and JP-A 10-330604 relate to a polymer blend produced by using amorphous polyimide or polyether imide, and lack the description or suggestion of the crystalline polyimide of the present invention.
Melt polymerization, solution polymerization, solid-phase polymerization, interfacial polymerization, etc., are known as the methods for the production of a polyimide. Among the above methods, the hydrolysis of a polyamic acid and the imidation reaction competitively proceed in either of the method to imidate by thermal cyclization and the method to imidate by chemical cyclization and, accordingly, polyimide having sufficiently high polymerization degree cannot be produced.
Reaction of a tetracarboxylic acid dianhydride with a diisocyanate is also known as a process for the production of a polyimide, however, it is difficult to synthesize the objective polymer in high polymerization degree because dilsocyanate is expensive and extremely unstable.
Another known method for the production of a semi-aromatic polyimide is the reaction of a salt composed of an aliphatic diamine and an aromatic tetracarboxylic acid or a salt composed of an aliphatic diamine and an aromatic tetracarboxylic acid dialkyl ester under high pressure (ACS Polym. Prep. 1994 35(1), Macromolecules 1994, 27, 4101-4105, Macromolecules 1995, 28, 6368-6370, Macromol, Chem. Phys. 198, 519-530 (1997), Macromolecules 1997, 30, 1921-1928, Journal of Polymer Science: Part A: Polymer Chemistry, Vol.36, 39-47 (1998), etc.), however, the polymerization degree represented by &eegr;
inh
c
(dL/g) of the produced semi-aromatic polyimide is 0.45 to 2.89 or thereabout and a polyimide having high polymerization degree cannot be produced.
The object of the present invention is to provide a thermoplastic resin composition composed of a crystalline polyimide and a thermoplastic polyester and having excellent heat-resistance, moldability and/or mechanical properties such as high elastic modulus and Izod impact strength and provide its production process.
Another object of the present invention is to provide a molded article such as a surface-mounting electronic part and a film produced by using the above thermoplastic resin composition.
The other object of the present invention is to provide a crystalline polyimide having high polymerization degree and usable as the above crystalline polyimide and provide its production process.
As a result of vigorous investigation by the inventors to achieve the above objects, it has been found that the objects can be achieved by blending a crystalline polyimide with a thermoplastic polyester in a manner to com
Ishiwata Toyoaki
Ozaki Daisuke
Sadanobu Jiro
Toyohara Kiyotsuna
Bissett Melanie
Seidleck James J.
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