Stock material or miscellaneous articles – Hollow or container type article – Polymer or resin containing
Reexamination Certificate
1997-11-05
2002-11-26
Nolan, Sandra M. (Department: 1772)
Stock material or miscellaneous articles
Hollow or container type article
Polymer or resin containing
C428S036910, C428S419000, C525S066000, C525S09200D, C525S133000, C525S150000, C525S261000
Reexamination Certificate
active
06485806
ABSTRACT:
The present invention relates to multilayered moldings with good hot water resistance, antifreeze resistance, chemical resistance, heat resistance, abrasion resistance, gas permeation resistance and interlayer adhesion.
BACKGROUND ART
Polyphenylene sulfide resins (hereinafter referred to as PPS resins) have good heat resistance, hot water resistance, chemical resistance and flame resistance, while having good electric characteristics, and there is increasing a great demand for the applications of those PPS resins to electric and electronic parts and also to car parts. Recently, Japanese Patent Publication No. 6-98673 has disclosed hollow molding materials comprising PPS resins, referring to the characteristics of the resins.
However, PPS resins require high molding temperatures while solidifying rapidly. Therefore, where those resins are molded, for example, through blow molding or extrusion to give moldings with good outward appearance, the temperature of the molds to be used must be high. For these reasons, the PPS resins are not favorable in view of their moldability and economic aspects.
On the other hand, regarding hollow moldings of thermoplastic resins, such as ducts and fuel lines in car engine rooms, various techniques of producing them have been popularized through blow molding and extrusion of polyamide resins and saturated polyester resins.
However, since single-layered hollow moldings of those conventional thermoplastic resins such as polyamide resins and saturated polyester resins have poor heat resistance, chemical resistance, gas permeation resistance and abrasion resistance, their applications are limited. Therefore, products with much more improved heat resistance, chemical resistance, gas permeation resistance and abrasion resistance are required.
Given this situation, it may be considered to laminate a thermoplastic resin except PPS resins and a PPS resin to obtain laminate moldings having both the characteristics of the former thermoplastic resin characterized by its good mechanical properties, moldability and availability, and the characteristics of the latter PPS resin characterized by its good heat resistance, hot water resistance and chemical resistance. However, even if a PPS resin and a thermoplastic resin except PPS resins are directly laminated together, interlayer peeling is inevitable in the resulting laminates because of the absence of interlayer adhesiveness between the two different resins, and therefore the intended moldings could not be obtained.
On the other hand, a method of interposing an adhesive layer between a PPS resin and a thermoplastic resin except PPS resins to give laminates of the two resins has been proposed. For example, Japanese Patent Application Laid-Open No. 5-193060 discloses a laminate structure comprising a PPS resin layer and a polyolefin resin layer as laminated via an adhesive therebetween.
However, where multilayered structures are produced through co-extrusion according to the method of interposing such an adhesive layer between two different resin layers, an increased number of extruders are needed, resulting in that the working equipment is complicated and requires time-consuming operations. Therefore, the method is problematic in that it is uneconomical and disadvantageous in practical use.
One object of the present invention is to provide multilayered moldings with well-balanced and good heat resistance, hot water resistance, chemical resistance to, for example, zinc chloride, calcium chloride and amines, gas permeation resistance, abrasion resistance, moldability and interlayer adhesion.
Another object of the invention is to provide PPS resin compositions with good surface smoothness and moldability, which can be formed into multilayered moldings with such good characteristics.
DISCLOSURE OF THE INVENTION
The invention is summarized as follows:
A multilayered molding comprising a laminate structure of (A) a layer of a polyphenylene sulfide resin (hereinafter referred to as PPS resin) composition and (B) a layer of a thermoplastic resin except PPS resins, in which the PPS resin composition constituting the layer (A) comprises (A1) 100 parts by weight of a PPS resin, (A2) from 1 to 80 parts by weight of a thermoplastic resin having at least one functional group selected from epoxy groups, acid anhydride groups, carboxyl group and its salts, and carboxylate groups, and (A3) from 5 to 80 parts by weight of a thermoplastic resin which is similar in kind to the thermoplastic resin constituting the layer (B).
BEST MODES OF CARRYING OUT THE INVENTION
The constituent components and the structure of the multilayered, tubular, thermoplastic resin moldings of the invention are described in detail hereinunder.
The PPS resin (A1) for use in the invention is a polymer comprising a repeating unit of the following structural formula in an amount of preferably 70 mol % or more, more preferably 90 mol % or more.
PPS resins usable in the invention include relatively low molecular weight polymers to be produced, for example, by the method described in Japanese Patent Publication No. 45-3368, and substantially linear, relatively high molecular weight polymers to be produced, for example, by the method described in Japanese Patent Publication No. 52-12240; and the former polymers as produced by the method described in Japanese Patent Publication No. 45-3368 could be heated in an oxygen atmosphere or could be heated in the presence of a crosslinking agent such as peroxides to thereby make them have an increased molecular weight, prior to being used in the invention.
PPS resins obtained by any methods can be used in the invention, but preferred are substantially linear, relatively high molecular weight polymers.
PPS resins for use in the invention could be so modified as to comprise any of repeating units of the following structural formulae in an amount of less than 30 mol % of the total repeating units.
Desirably, the PPS resin (A1) to be used in the invention is one as prepared through ordinary polymerization such as that mentioned above followed by deionization to be effected by washing the polymers with an aqueous acid solution or an organic solvent.
The washing of PPS resins with an aqueous acid solution may be effected, for example, as follows:
Acids to be used for the washing are not specifically defined, provided that they do not decompose PPS resins. For example, employable is any of acetic acid, hydrochloric acid, sulfuric acid, phosphoric acid, silicic acid, carbonic acid and propionic acid. Of those, preferred are acetic acid and hydrochloric acid. However, nitric acid and others that decompose and deteriorate PPS resins are unfavorable.
To wash PPS resins with such an aqueous acid solution, for example, the resins are dipped in the solution optionally with stirring or heating them. In one example using acetic acid, a powdery PPS resin is dipped in an aqueous acetic acid solution having a pH of 4, and stirred therein for 30 minutes under heat at 80 to 90° C. to obtain sufficient results. It is desirable that the acid-treated PPS resins are additionally washed several times with cold or warm water to thereby physically remove the remaining acid or salt.
Water to be used for the additional washing is preferably distilled or deionized water, as not interfering with the favorable chemical modifications in the acid-treated PPS resins.
PPS resins for use in the invention may be washed with hot water, for example, in the manner mentioned below.
Hot water to be used for the washing is preferably at 100° C. or higher, more preferably at 120° C. or higher, even more preferably at 150° C. or higher, especially preferably at 170° C. or higher.
It is desirable that the hot water to be used for the treatment is distilled or deionized water, as producing favorable chemical modifications in the treated PPS resins. For the hot water treatment, in general, a predetermined amount of the PPS resin to be treated is put into water in a pressure container and heated therein with stirring. Regarding the ratio of the PPS resin to water, it is
Ishio Atsushi
Kobayashi Kazuhiko
Matsui Kazufumi
Ohno Kazuya
Shimasaki Norio
Nolan Sandra M.
Schnader Harrison Segal & Lewis LLP
Toray Industries Inc.
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