Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Mixing of two or more solid polymers; mixing of solid...
Patent
1995-08-23
1997-09-23
Zemel, Irina S.
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Mixing of two or more solid polymers; mixing of solid...
525322, 525323, C08F21006, C08F29708
Patent
active
056705808
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to a novel propylene block copolymer, a process for preparing the same, a hydrogenated propylene block copolymer and a modified copolymer of the propylene block copolymer. More specifically, the present invention relates to a propylene block copolymer which is excellent in balance between stiffness and impact resistance, is free from the generation of a gel, can optionally control the activation energy of melt flow, has a good moldability, and possesses an unsaturated group useful for a chemical reaction such as a modification reaction or a graft reaction; a process for efficiently preparing the propylene block copolymer; a hydrogenated propylene block copolymer using the propylene block copolymer; and a modified copolymer which can be obtained by modifying the propylene block copolymer to introduce, into its reactive unsaturated group, a functional group such as a hydroxyl group, a carboxyl group, an epoxy group, a nitro group, an amino group, an acyl group, a sulfone group or a halogen group and which is excellent in adhesive properties, printability, hydrophilic nature, polymer modifying properties, antistatic properties and flame resistance.
BACKGROUND ART
In recent years, there has been a demand to decrease the wall thickness and to reduce the weight of injection-molded articles from the viewpoints of the saving resources and energy. Since an improvement in the balance between stiffness and impact resistance of a polypropylene permits a decrease in the wall thickness and reduction of the weight of the molded articles, various techniques have been suggested for the purpose of improving the physical properties of polypropylene. For example, there have been suggested Japanese Patent Application Laid-open Nos. 113695/1979, 5969/1980, 115417/1980, 69821/1986, 69822/1986 and 69823/1986. However, with regard to the balance between the stiffness and impact resistance, a further improvement has been desired.
Also for propylene polymers, resin designs have been made by imparting an additional property (particularly melt tension) thereto so as to sufficiently utilize characteristics peculiar to the propylene polymers, thereby developing the applications of the same. For example, in Japanese Patent Application Laid-open Nos. 185490/1993, 194659/1993, 194778/1993, 194793/1993, 200849/1993, 202137/1993, 202143/1993, 202219/1993, 202237/1993, 202238/1993, 202248/1993, 209062/1993, 212771/1993, 212774/1993, 214178/1993, 220829/1993, 222121/1993, 222122/1993, 222251/1993, 228995/1993, 237930/1993 and 239232/1993, techniques have been disclosed in which a preliminary polymerization catalyst is combined with a preliminary polymerization process to impart sufficiently improved melt tension to the propylene polymer and a resin composition containing this polymer. However, in the techniques disclosed in these publications, at least three preliminary polymerization steps are required prior to a main polymerization, which makes the operation complex. In addition, the reactivity of the polymerization is usually poor, and there is also a problem that a non-conjugated chain diene is used which tends to bring about cyclization or a crosslinking reaction in the reaction.
Moreover, the homopolymers and copolymers of propylene have excellent mechanical strength, gloss, transparency, moldability, moisture resistance and chemical resistance in addition to being inexpensive, and therefore they have widely been used for various applications in many fields. However, these propylene polymers, since having a non-polar molecular structure, are noticeably and inconveniently poor in compatibility with other substances, adhesive properties, coating properties, printability and antistatic properties.
In order to eliminate such drawbacks, for example, there have been suggested (1) a process of partially oxidizing the polymer by a treatment with a solution containing chromic acid or a flame treatment, (2) a process of graft-modifying the polymer with a polar group-containing compound such as male
REFERENCES:
patent: 5286564 (1994-02-01), Cecchin et al.
patent: 5476903 (1995-12-01), Shinozaki
Machida Shuji
Tazaki Toshinori
Idemitsu Kosan Co. Ltd.
Zemel Irina S.
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