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
2002-06-10
2004-01-13
Short, Patricia A. (Department: 1712)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Mixing of two or more solid polymers; mixing of solid...
C525S537000, C524S539000
Reexamination Certificate
active
06677406
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a resin composition incorporating a polyarylene sulfide (hereafter abbreviated as PAS) with an increased glass transition temperature (Tg), as well as a molded product, a heat resistant molded product produced therefrom, and a soldered molded product of such a heat resistant molded product.
2. Description of the Related Art
PAS compounds, of which polyphenylene sulfide (hereafter abbreviated as PPS) is a representative example, have high melting points, exhibit superior properties of flame resistance and chemical resistance, and offer good fluidity during molding, and as a result, they are widely used as an engineering plastic for the injection molding of various electronic components, mechanical components and automobile components. However, PPS has a low Tg value, and loses durability under high temperature conditions exceeding 100° C., making it unsuitable for use in hot water equipment components and the like. Furthermore, PPS exhibits insufficient heat resistance for use in fields which require high heat resistance such as the use of lead-free solder with electronic circuit board components.
Various blends of PAS with other polymers such as polycarbonate, polyphenylene oxide, polysulfone, and polyether sulfone have been proposed with the object of improving the heat resistance, the impact resistance and the flame resistance of PAS (Japanese Examined Patent Application, Second Publication No. Sho 53-13468, Japanese Examined Patent Application, Second Publication No. Sho 56-34032, and Japanese Unexamined Patent Application, First Publication No. Sho 59-164360). However, in these methods, the Tg of the PAS within the blended product shows absolutely no improvement from the Tg of unblended PAS.
Blends of PAS with aromatic polyesters are disclosed in Japanese Unexamined Patent Application, First Publication No. Sho. 53-57255 and others. However, in these cases also, although the blends are improved in impact resistance, etc., the Tg of the PAS within the blended product shows absolutely no improvement over the Tg of unblended PAS.
Consequently, a resin composition incorporating PAS, which is able to retain a high degree of strength and rigidity and also maintain a good level of hot water resistance, even under high temperature conditions exceeding 100° C., has remained elusive until now.
SUMMARY OF THE INVENTION
An object of the present invention is to raise the Tg value of PAS in order to provide a resin composition incorporating PAS and a molded product produced therefrom, which exhibits superior strength and rigidity and good hot water resistance under high temperature conditions exceeding 100° C.
Furthermore, another object of the present invention is to provide a heat resistant molded product with even greater heat resistance by heat treating a molded product produced from the above resin composition.
In addition, yet another object of the present invention is to provide a soldered molded product by increasing the solder resistance temperature of the above heat resistant molded product.
As a result of intensive research aimed at resolving the issues outlined above, the inventors of the present invention discovered that by mixing PAS with an aromatic polyester of a specific structure and with a Tg value higher than that of PAS, a composition could be obtained which retained the superior moldability of PAS, and yet exhibited improved levels of Tg and heat resistance, and were thus able to complete the present invention.
In other words, the present invention relates to a resin composition comprising a polyarylene sulfide, and an aromatic polyester represented by a general formula (1) shown below, and with a higher glass transition temperature than the polyarylene sulfide,
(wherein, Ar represents either an aromatic ring or a heterocyclic ring; R
1
to R
4
each represent a hydrogen atom or an alkyl group of 1 to 8 carbon atoms, which may be the same or different, provided that at least one of these groups is an alkyl group of 1 to 8 carbon atoms; Y represents a single bond, a bivalent hydrocarbon group of 1 to 12 carbon atoms which may incorporate a hetero atom, an oxygen atom, a sulfur atom, a nitrogen atom, a linkage group in which hetero atoms are bonded together, or a linkage group comprising bonding between hetero atoms and carbon atoms; and n is an integer representing the number of repeating units), as well as a molded product produced using such a composition.
Furthermore, the present invention also relates to a heat resistant molded product obtained by heat treating a molded product formed from the aforementioned resin composition.
In addition, the present invention also relates to a soldered molded product produced by soldering the aforementioned heat resistant molded product.
DETAILED DESCRIPTION OF THE INVENTION
First, a description of a resin composition of the present invention will be given.
A resin composition of the present invention incorporates PAS, and the aforementioned aromatic polyester represented by the general formula (1) with a higher Tg value than PAS. The Tg values were determined using a dynamic viscoelasticity measuring device, in the manner described below. Namely, under conditions including a frequency of 1 Hz and a rate of temperature increase of 4° C./minute, the temperature at the lowest temperature peak of the tan &egr; peaks obtained was recorded as the value of Tg (° C.) for PAS in the present invention. The values of Tg for both unblended PAS and the PAS within a composition of the present invention were measured in this manner.
The PAS used in the compositions of the present invention is a polymer represented by the structural formula (-Ar-S-)n (wherein Ar represents an arylene group). Examples of the arylene group (-Ar-) include bivalent aromatic residues such as p-phenylene, m-phenylene, o-phenylene, 2,6-naphthalene and 4,4′-biphenylene, or bivalent aromatic residues incorporating at least two 6 carbon membered aromatic rings such as the residues shown below,
although each of the aforementioned aromatic rings may also comprise substituent groups such as F, Cl, Br or CH
3
. These polymers may be homopolymers, random copolymers or block copolymers, and may be linear, branched or cross linked. Mixtures of these polymers may also be used.
Of the above polymers, polymers in which the polyphenylene sulfide represented by the general formula (3) shown below accounts for at least 70 ml % of the structural units are preferred, and polymers with at least 90 mol % are even more preferred.
The other structural units incorporated within the PAS, other than the PPS structural units, may include any of the aforementioned arylene groups.
This type of PAS can be synthesized by (1) a reaction between a halogen substituted aromatic compound and an alkali sulfide (refer to U.S. Pat. No. 2,513,188, Japanese Examined Patent Application, Second Publication No. Sho 44-27671, and Japanese Examined Patent Application, Second Publication No. Sho 45-3368), (2) a condensation reaction of a thiophenol in the presence of an alkali catalyst or a copper salt (refer to U.S. Pat. No. 3,274,165), (3) a condensation reaction between an aromatic compound and sulfur chloride in the presence of a Lewis acid catalyst (refer to Japanese Examined Patent Application, Second Publication No. Sho 46-27255), with the particular synthetic method used being chosen depending on the polymer required.
The aromatic polyester used in the present invention is represented by the general formula (1) shown below,
(wherein, Ar represents either an aromatic ring or a heterocyclic ring; R
1
to R
4
each represent a hydrogen atom or an alkyl group of 1 to 8 carbon atoms, which may be the same or different, provided that at least one of these groups is an alkyl group of 1 to 8 carbon atoms; Y represents a single bond, a bivalent hydrocarbon group of 1 to 12 carbon atoms which may incorporate a hetero atom, an oxygen atom, a sulfur atom, a nitrogen atom, a linkage group in which hetero atoms are bond
Furusawa Takashi
Kawashima Kiyotaka
Ogawa Ikuko
Ono Yoshiyuki
Santo Yoshinari
Armstrong Kratz Quintos Hanson & Brooks, LLP
Dainippon Ink and Chemicals Inc.
Short Patricia A.
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