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
1999-11-23
2001-12-18
Boykin, Terressa M. (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...
Reexamination Certificate
active
06331591
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a cycloolefin copolymer resin composition having well-balanced transparency and impact resistance and a process for preparing the composition.
BACKGROUND ART
Cycloolefin copolymers have excellent moldability, dimensional stability, transparency and moisture barrier. However, the impact strength thereof is not sufficient and, therefore, improvement thereof has been conventionally investigated. It has been demanded to further improve the impact resistance with maintaining an excellent transparency that the cycloolefin copolymers possess.
It is generally known that alloying transparent brittle thermoplastic resins with incompatible rubber components enhances the impact resistance. This manner is also effective for cycloolefin copolymers. For example, a cycloolefin copolymer composition reinforced with commercially available block copolymers (such as SBS, SEBS and SIS) as a rubber component is disclosed in Japanese Patent Publication Kokai No. 1-256548.
In general, the impact resistance and the transparency of alloys of polymers incompatible with each other are greatly influenced by phase morphology of components constituting the polymer alloys.
Impact resistance of brittle thermoplastic resins cannot be always improved by merely alloying with rubber components. It is known that revelation of impact resistance is influenced by domain size of the rubber components dispersed in the continuous phase of the brittle thermoplastic resins, and the domain size appropriate for the revelation of impact resistance varies for every thermoplastic resin.
In many cases, the refractive indexes of a thermoplastic resin and a rubber component do not completely agree all over the visible ray band, so an excellent transparency that brittle thermoplastic resins possess is not always prevented from lowering by merely matching the refractive indexes of components constituting a polymer alloy. Therefore, the transparency of a polymer alloy is swayed by determination of the wave length at which the refractive indexes should be matched or determination of the domain size to be formed of the rubber component.
Objects of the present invention are to provide a cycloolefin copolymer resin composition having well-balanced impact resistance and transparency, and a process for preparing the composition
DISCLOSURE OF THE INVENTION
In accordance with the first embodiment of the present invention, there is provided a transparent cycloolefin copolymer resin composition comprising (A) a cycloolefin copolymer and (B) 1 to 100 parts by weight, per 100 parts by weight of said cycloolefin copolymer, of at least one rubber-like polymer selected from the group consisting of (B1) an aromatic vinyl-isobutylene copolymer and (B2) an aromatic vinyl-conjugated diene copolymer, wherein the difference in refractive index (nD) at 20° C. between the components (A) and (B) is at most 0.015 and the particle size of the component (B) dispersed in the component (A) is from 0.4 to 3 &mgr;m.
In accordance with the second embodiment of the present invention, there is provided a resin composition wherein the above-mentioned resin composition of the first embodiment is further incorporated with (C) 1 to 80 parts by weight, per 100 parts by weight of the component (A), of a core-shell polymer, the difference in refractive index (nD) at 20° C. between the components (A) and (C) is at most 0.015, and the particle size of the primary particles of the component (C) is from 0.1 to 1.0 &mgr;m.
In accordance with the third embodiment of the present invention, there is provided a process for preparing a transparent cycloolefin copolymer resin composition which comprises kneading (A) a cycloolefin copolymer and (B) 1 to 100 parts by weight, per 100 parts by weight of said cycloolefin copolymer, of at least one rubber-like polymer selected from the group consisting of (B1) an aromatic vinyl-isobutylene copolymer and (B2) an aromatic vinyl-conjugated diene copolymer in the presence of (D) 0.0001 to 6 parts by weight, per 100 parts by weight of the component (A), of an organic peroxide at a temperature of 180 to 300° C.
In the above process, the components (A) and (B) may be kneaded together with (C) 1 to 80 parts by weight, per 100 parts by weight of the component (A), of a core-shell polymer.
BEST MODE FOR CARRYING OUT THE INVENTION
The cycloolefin copolymers (hereinafter referred to as “COC”) used in the present invention are amorphous polymers having a cyclic olefin structure, and preferably have a glass transition temperature of 50 to 250° C., especially 80 to 200° C., more especially 80 to 160° C. If the glass transition temperature is less than 50° C., the rigidity is not sufficient and, therefore, a balance between rigidity and impact resistance is deteriorated. If the glass transition temperature is more than 250° C., the processability is lowered. Preferably, the COC used in the present invention comprises, based on the total weight thereof,
1 to 99% by weight of at least one cyclic olefin, preferably a cyclic olefin of the formula (I), (II), (III), (IV), (V), (VI) or (VII) described below, wherein R
1
to R
8
are the same or different and each is hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms, provided that at least two of R
1
to R
8
may form a ring, and n in the formula (VII) is an integer of 2 to 10,
99 to 1% by weight of at least one non-cyclic olefin, preferably a non-cyclic olefin of the formula (VIII) described below, wherein R
9
to R
12
are the same or different and each is hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms, and
0 to 20% by weight of other vinyl compounds having at least one double bond, e.g., (meth)acrylic acid, alkyl (meth)acrylate, (meth)acrylonitrile and vinyl acetate. More preferably, the COC used in the present invention comprises 40 to 90% by weight of at least one of cyclic olefins of the formulas (I) to (VII) and 60 to 10% by weight of a non-cyclic olefin of the formula (VIII).
Preferable COCs are copolymers of a cyclic olefin having a norbornene based structure, preferably norbornene, tetracyclododecene or cyclic olefins having a structure derived from them, and a non-cyclic olefin having a terminal double bond, e.g., an &agr;-olefin, preferably ethylene or propylene. Among them, norbornene-ethylene, norbornene-propylene, tetracyclo-dodecene-ethylene and tetracyclododecene-propylene copolymers are particularly preferred.
Commercially available cycloolefin copolymers, e.g., those available under the trade mark “Topas” made by Hoechst Aktiengesellschaft, Germany, and the trade mark “APEL” made by Mitsui Petrochemical Industries, Ltd. can also be used in the present invention as the COC.
Preferably the COC suitable for the objects of the present invention has a viscosity number of 25 to 200 ml/g, especially 40 to 120 ml/g, more especially 40 to 80 ml/g, measured in decalin at 135° C. If the viscosity number is less than 25 ml/g, the rigidity of molded articles obtained from the resin compositions is insufficient, and if the viscosity number is more than 200 ml/g, the molding processability of the resin compositions tend to lower.
An aromatic vinyl-isobutylene copolymer (B1) and an aromatic vinyl-conjugated diene copolymer (B2) are used in the present invention as the rubber-like polymer (B) to be incorporated into the cycloolefin copolymer (A). These may be used alone or in admixture thereof. Examples of the aromatic vinyl compound are, for instance, styrene, &agr;-methylstyrene, p-methylstyrene, chlorostyrene, bromostyrene, vinyl naphthalene, and the like.
Examples of the aromatic vinyl-isobutylene copolymer (B1) are, for instance, styrene-isobutylene block copolymer (SIB), styrene-isobutylene-styrene block copolymer (SIBS), isobutylene-styrene-isobutylene block copolymer (IBSIB), styrene-isobutylene random copolymer, and the like. These may be used alone or in admixture thereof. Among them, styrene-isobutylene block copolymer and styrene-isobutylene-styrene block copolymer are particularly preferred. These aromatic vinyl-iso
Aoyama Taizo
Kimura Katsuhiko
Miyamoto Masahiro
Armstrong Westerman Hattori McLeland & Naughton LLP
Boykin Terressa M.
Kaneka Corporation
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