AU764796B2 - Polyethylene resin composition for rotational molding and rotational molded product using the composition - Google Patents
Polyethylene resin composition for rotational molding and rotational molded product using the composition Download PDFInfo
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Description
AUSTRALIA
PATENTS ACT 1990 COMPLETE SPECIFICATION NAME OF APPLICANT(S): Mitsui Chemicals, Inc.
ADDRESS FOR SERVICE: 0* DAVIES COLLISON CAVE Patent Attorneys 1 Little Collins Street, Melbourne, 3000.
INVENTION TITLE: :0.0.0 .0.0 Polyethylene resin composition for rotational molding and rotational molded product using the composition The following statement is a full description of this invention, including the best method of performing it known to me/us:-
IA
FIELD OF THE INVENTION The present invention relates to a polyethylene resin composition for rotational molding and a rotational molded product using the composition. More particularly, the invention relates to a polyethylene resin composition 1: 0 suitable for the manufacture of hollow molded articles or oeoo *complicated molded articles such as water storage tank, especially a polyethylene resin composition for rotational molding from which rotational molded products having excellent impact resistance and environmental 15 stress crack resistance (ESCR) can be produced, and also relates to a rotational molded product using the composition.
BACKGROUND OF THE INVENTION Various articles such as tanks, containers, daily use goods, furniture, gardening goods and outdoor goods have hitherto manufactured by rotational molding. The materials used for manufacturing these articles need to be excellent in mechanical strength properties, particularly in impact resistance and environmental c,' SF-684 2 stress crack resistance (ESCR). As a rotational molding material that meets such needs, a palyethylene resin has been mainly employed.
The articles obtained by rotational molding of the polyethylene resin are excellent in one or two of impact resistance, rigidity and environmental stress crack resistance, but there are few which are excellent in all the properties. Hence, molded articles having much better balance of properties have been desired.
10 In Japanese Patent Laid-Open Publication No.
*oo 194537/1997 by the present applicant, a rotational molding resin which comprises an ethylene a-olefin random copolymer having a density of 0.920 to 0.955 g/cm 3 a melt index (MFR) of 1 to 20 g/10 min and a molecular weight distribution (Mw/Mn) of 2 to 3 and has a particle diameter of not more than 30 mesh is described. A rotational molded product produced from this resin is excellent particularly in balance between impact resistance, rigidity and environmental stress crack resistance (ESCR) and has no problem in practical use.
However, a polyethylene resin for rotational molding which can provide a rotational molded product superior to the rotational molded product produced from the above resin in the impact resistance and the environmental stress crack resistance (ESCR) is now desired.
Under such circumstances, the present inventors have earnestly studied to meet the needs, and as a result, they have found that a polyethylene rotational molded product having excellent impact resistance and environmental stress crack resistance can be obtained by rotational molding of a resin composition which comprises an ethylene a-olefin copolymer comprising ethylene and an a-olefin of 3 to 20 carbon atoms and having a density (ASTM D 1505) of 0.880 to 0.930 g/cm 3 and a melt flow rate (ASTM D 1238, 190 0 C, load of 2.16 kg) of 0.01 to 5 g/10 min and an ethylene homopolymer comprising ethylene or an ethylene a-olefin copolymer comprising ethylene and an a-olefin of 3 to 20 carbon atoms, that has a density of 0.931 to 0.974 g/cm 3 and a melt flow S 15 rate of 0.5 to 20 g/10 min, wherein the weight ratio is in the specific range and a blend consisting of the ethylene a-olefin copolymer and the ethylene homopolymer or the ethylene a-olefin copolymer has a density of 0.920 to 0.960 g/cm 3 and a melt flow rate of 1 to 10 g/10 min. Based on the finding, the present invention has been accomplished.
The present invention seeks to provide a polyethylene resin composition for rotational molding P:\OPERUcc\8619-00 spal.doc-08/07/03 -4from which a rotational molded product superior to the conventional rotational molded products in the impact resistance and the environmental stress crack resistance (ESCR) can be produced, and to provide a rotational molded product using the composition.
Accordingly, the present invention provides a polyethylene resin composition for rotational molding comprising: an ethylene a-olefin copolymer which comprises ethylene and an a-olefin of 3 to 20 carbon atoms and which has a density (ASTM D1505) of 0.880 to 0.930 g/cm 3 and a melt flow rate (MFR) (ASTM D 1238, 190 0 C, load: 2.16 Kg) of 0.01 to 5 g/10 min, and an ethylene homopolymer which comprises ethylene or an ethylene a-olefin copolymer which comprises ethylene and an a-olefin of 3 to 20 carbon atoms, which has a density (ASTM D 1505) of 0.931 to 0.974 g/cm 3 and a melt flow rate (MFR) (ASTM D 1238, 1900, load: 2.16 kg) of 0.5 to 20 20 min, wherein: the weight ratio of the ethylene a-olefin copolymer to the ethylene homopolymer or the o o° oe SF-684 ethylene a-olefin copolymer is in the range of 10/90 to 50/50, and a blend consisting of the ethylene a-olefin copolymer and the ethylene homopolymer or the ethylene a-olefin copolymer has a density (ASTM D 1505) of 0.920 to 0.960 g/cm 3 and a melt flow rate (MFR) (ASTM D 1238, 190 0 C, load: 2.16 kg) of 1 to 10 g/10 min.
The polyethylene resin composition for rotational molding according to the invention can take the following 10 four embodiments classified based on the type of an olefin polymerization catalyst used in the preparation of the ethylene a-olefin copolymer the ethylene homopolymer and the ethylene c-olefin copolymer 15 a resin composition wherein the ethylene aolefin copolymer the ethylene homopolymer and the ethylene a-olefin copolymer are each a (co)polymer prepared by the use of a metallocene type olefin polymerization catalyst; a resin composition wherein the ethylene aolefin copolymer is a copolymer prepared by the use of a metallocene type olefin polymerization catalyst, and the ethylene homopolymer and the ethylene a-olefin copolymer are prepared by the use of a Ziegler type olefin polymerization catalyst; SF-684 6 a resin composition wherein the ethylene aolefin copolymer the ethylene homopolymer and the ethylene a-olefin copolymer are prepared by the use of a Ziegler type olefin polymerization catalyst; and a resin composition wherein the ethylene aolefin copolymer is prepared by the use of a Ziegler type olefin polymerization catalyst, and the ethylene homopolymer and the ethylene a-olefin copolymer (B) are prepared by the use of a metallocene type olefin 10 polymerization catalyst.
Of the above resin compositions to preferable are the resin compositions and each of which comprises the ethylene a-olefin copolymer (A) prepared by the use of a metallocene type olefin 15 polymerization catalyst and the ethylene homopolymer or the ethylene a-olefin copolymer prepared by the use of a metallocene type or Ziegler type olefin polymerization catalyst. In particular, a composition comprising the ethylene a-olefin copolymer prepared by the use of a metallocene type olefin polymerization catalyst and the ethylene homopolymer or the ethylene a-olefin copolymer prepared by the use of a Ziegler type olefin polymerization catalyst is preferable.
The rotational molded product according to the present invention comprises the above-described polyethylene resin composition for rotational molding.
DETAILED DESCRIPTION OF THE INVENTION The polyethylene resin composition for rotational molding according to the invention and the rotational molded product using the composition are described in detail hereinafter.
The polyethylene resin composition for rotational molding according to the invention comprises an ethylene a-olefin copolymer and an ethylene homopolymer or an ethylene a-olefin copolymer having a density different from that of the copolymer and when the 15 resin composition consists-of the ethylene a-olefin copolymer and the ethylene homopolymer or the ethylene a-olefin copolymer the density and the melt flow rate of this resin composition are in'the specific ranges.
Ethylene a-olefin copolymer (A) The ethylene a-olefin copolymer for use in the invention is a copolymer of ethylene and an a-olefin having from 3 to 20 carbon atoms, and has a density (ASTM D 1505) of 0.880 to 0.930 g/cm 3 preferably 0.885 to 0.925 g/cm 3 more preferably.0.890 to 0.920 g/cm 3 and a melt flow 8 rate (MFR) (ASTM D 1238, 190'C, load: 2.16 kg) of 0.01 to g/10 min, preferably 0.05 to 4.5 g/10 min, more preferably 0.1 to 4.0 g/10 min.
Examples of the a-olefins of 3 to 20 carbon atoms include propylene, 1-butene, 1-pentene, 2-methyl-1-butene, 3-methyl-l-butene, 1-hexene, 3-methyl-1-pentene, 4methyl-l-pentene, 3,3-dimethyl-1-butene, 1-heptene, methyl-l-hexene, dimethyl-1-pentene, trimethyl-l-butene, ethyl-l-pentene, 1-octene, methyl-1-pentene, dimethyl-lhexene, trimethyl-l-pentene, ethyl-l-hexene, methylethyl- 1-pentene, diethyl-l-butene, propyl-1-pentene, 1-decene, methyl-1-nonene, dimethyl-1-octene, trimethyl-l-heptene, ethyl-l1-octene, methylethyl-1-heptene, diethyl-1-hexene, 1-dodecene and 1-hexadodecene.
These ax-olefins can be used singly or in combination of two or more kinds.
The ethylene a-olefin copolymer preferably used in the invention is an ethylene 1-butene copolymer, an ethylene 1-pentene copolymer, an ethylene 1-hexene copolymer, an ethylene 4-methyl-1-pentene copolymer or an ethylene 1-octene copolymer.
The ethylene a-olefin copolymer having the above properties can be prepared by copolymerizing ethylene and an a-olefin having from 3 to 20 carbon atoms in the presence of a conventional Ziegler type or metallocene type olefin polymerization catalyst, preferably a metallocene type olefin polymerization catalyst.
Ethylene homopolymer or ethylene a-olefin copolymer (B) The ethylene homopolymer or the ethylene a-olefin copolymer for use in the invention is a polymer of only ethylene or a copolymer of ethylene and an a-olefin having from 30 to 20 carbon atoms, and has a density (ASTM D 1505) of 0.931 to 0.974 g/cm 3 preferably 0.935 to 0.970 g/cm 3 more preferably 0.938 to 0.968 g/cm 3 and a melt flow rate (MFR) (ASTM D 1238, 190°C, load: 2.16 kg) of 0.5 to g/10 min, preferably 1.0 to 19 g/10 min, more preferably 1.5 to 18 g/10 min.
Examples of the a-olefins having from 3 to 20 carbon atoms include the same a-olefins having from 3 to 20 carbon atoms as used for constituting the aforesaid ethylene a-olefin copolymer The ca-olefins having from 3 to 20 carbon atoms can be used singly or in combination of two or more kinds.
The ethylene a-olefin copolymer preferably used in the invention is an ethylene 1-butene copolymer, an ethylene 1-pentene copolymer, an ethylene 1-hexene cop.olymer, an ethylene 4-methyl-l-pentene copolymer or an ethylene 1-octene copolymer.
The ethylene homopolymer or the ethylene a-olefin copolymer having the above properties can be prepared by homopolymerizing ethylene or copolymerizing ethylene and an a-olefin having from 3 to 20 carbon atoms in the presence of a conventional Ziegler type or metallocene type olefin polymerization catalyst.
When an ethylene a-olefin copolymer prepared by the use of a metallocene type olefin polymerization catalyst is used as, the ethylene a-olefin copolymer (A) in the invention, an ethylene homopolymer or an ethylene a-olefin copolymer prepared by the use of a metallocene type olefin polymerization catalyst can be used as the ethylene homopolymer or the ethylene a-olefin copolymer or an ethylene homopolymer or the ethylene aolefin copolymer prepared by the use of a Ziegler type olefin polymerization catalyst may be used as the ethylene homopolymer or the ethylene a-olefin copolymer 15 When an ethylene a-olefin copolymer prepared by the use of a Ziegler type olefin polymerization catalyst is used as the ethylene a-olefin copolymer an ethylene homopolymer or an ethylene a-olefin copolymer prepared by the use of a Ziegler type olefin polymerization catalyst is used as the ethylene homopolymer or the ethylene a-olefin copolymer (B) Of the above cases, a combination of the ethylene a a-olefin copolymer prepared by the use of a metallocene type olefin polymerization catalyst and the SF-684 11 ethylene homopolymer (component prepared by the use of a Ziegler type olefin polymerization catalyst is preferable.
Polyethylene resin composition for rotational molding The polyethylene resin composition for rotational molding according to the invention comprises the ethylene a-olefin copolymer and the ethylene homopolymer or the ethylene a-olefin copolymer In the resin composition, the weight ratio 10 of the ethylene a-olefin copolymer to the ethylene homopolymer or the ethylene a-olefin copolymer is in the range of 10/90 to 50/50, preferably 15/85 to 45/55, more preferably 20/80 to 40/60.
With respect to the polyethylene resin composition for rotational molding according to the invention, a blend consisting of the ethylene a-olefin copolymer (A) and the ethylene homopolymer or the ethylene a-olefin copolymer has a density (ASTM D 1505) of 0.920 to 0.960 g/cm 3 preferably 0.922 to 0.958 g/cm 3 more preferably 0.925 to 0.955 g/cm 3 particularly preferably 0.930 to 0.955 g/cm 3 and a melt flow rate (MFR) (ASTM D 1238, 190 0 C, load: 2.16 kg) of 1 to 10 g/10 min, preferably 1.5 to 9 g/10 min, more preferably 2.0 to 8 min. When the density of the resin composition is in the above range, a rotational molded product having SF-684 12 excellent rigidity and mechanical strength can be obtained. When the melt flow rate of the resin composition is in the above range, the resin composition exhibits excellent rotational moldability and a polyethylene rotational molded product having good appearance can be obtained.
Preparation of polyethylene resin composition for rotational molding The polyethylene resin composition for rotational *eeS* 10 molding according to the invention comprises the ethylene "r x-olefin copolymer and the ethylene homopolymer or the ethylene a-olefin copolymer as described above.
To the polyethylene resin composition, additives, such as organic or inorganic filler, antioxidant, heat stabilizer, ultraviolet light absorber, flame retardant, antistatic agent, lubricant, blowing agent, colorant, release agent and weathering stabilizer, can be added in amounts not detrimental to the object of the invention.
S
The polyethylene resin composition for rotational molding according to the invention may be in the form of a powder or pellets, and the composition needs to be only in the form of a powder when subjected to rotational molding.
When the polyethylene resin composition for rotational molding according to the invention is in the 13 form of pellets, the pellets are pulverized into a powder prior to the rotational molding.
The powder of the polyethylene resin composition for rotational molding according to the invention is desired to have a particle diameter of not more than 30 mesh, preferably 40 to 100 mesh. When a powder having a particle diameter of the above range is used, the rotational moldability is excellent and a rotational molded product having good appearance can be obtained.
The polyethylene resin composition for rotational molding according to the invention can be obtained by melt kneading the ethylene a-olefin copolymer the ethylene homopolymer or the ethylene a-olefin copolymer and optionally, the aforesaid additives by a 15 conventional kneading device, such as an extruder, a Banbury mixer, a kneader or a Henschel mixer, and then powdering the kneadate by means of freeze pulverization or mechanical pulverization.
Further, the polyethylene resin composition for rotational molding according to the invention can be obtained also by continuously carrying out a step of copolymerizing ethylene and an u-olefin having from 3 to 20 carbon atoms in the presence of a metallocene type olefin polymerization catalyst to prepare the ethylene aolefin copolymer and a step of homopolymerizing ethylene or copolymerizing ethylene and an a-olefin having from 3 to 20 carbon atoms in the presence of a metallocene type or Ziegler type olefin polymerization catalyst to prepare the ethylene homopolymer or the ethylene a-olefin copolymer and then powdering the resulting resin composition by means of freeze pulverization or mechanical pulverization. Prior to the powdering, the resin composition may be melt kneaded with additives by a kneading device.
When the ethylene a-olefin copolymer and the ethylene homopolymer or the ethylene a-olefin copolymer are both prepared by the use of a Ziegler type olefin polymerization catalyst, the polyethylene resin composition for rotational molding according to the 15 invention can be obtained by continuously carrying out a step of copolymerizing ethylene and an a-olefin having from 3 to 20 carbon atoms in the presence of a Ziegler type olefin polymerization catalyst to prepare the ethylene aolefin copolymer and a step of homopolymerizing ethylene or copolymerizing ethylene and an a-olefin having from 3 to 20 carbon atoms in the presence of a Ziegler type olefin polymeri.zation catalyst to prepare the ethylene homopolymer or the ethylene a-olefin copolymer and then powdering the resulting resin composition by means of freeze pulverization or mechanical pulverization.
Prior to the powdering, the resin composition may be melt kneaded with additives by a kneading device.
The polyethylene resin composition for rotational molding according to the invention may be obtained by continuously carrying out a step of copolymerizing ethylene and an c-olefin having from 3 to 20 carbon atoms in the presence of a Ziegler type olefin polymerization catalyst to prepare the ethylene a-olefin copolymer and a step of homopolymerizing ethylene or copolymerizing ethylene and an a-olefin having from 3 to 20 carbon atoms in the presence of a metallocene type olefin polymerization catalyst to prepare the ethylene homopolymer or the ethylene a-olefin copolymer and then powdering the resulting resin composition by means of freeze 15 pulverization or mechanical pulverization. Prior to the powdering, the resin composition may be melt kneaded with additives by a kneading device.
Rotational molded product The rotational molded product according to the invention is produced by rotational molding of the abovedescribed polyethylene resin composition for rotational molding. The polyethylene resin composition subjected to.
rotational molding is in the form of a powder, as described above.
SF-684 16 The rotational molded product of the invention can be produced by a hitherto known process. Specifically, a powder of the polyethylene resin composition for rotational molding according to the invention is placed in a mold that rotates on one axis or two axes crossing at right angles or a mold that makes rocking rotation, and the powder is distributed onto an inside surface of the mold in a closed state and fused. Then, the mold is .cooled, and a molded product formed on the inside surface of the mold is taken out. Thus, the rotational molded C- *product of the invention can be obtained.
The inside surface of the mold may have embossed patterns, or it need not have.
15 EFFECT OF THE INVENTION The polyethylene resin composition for rotational molding according to the invention comprises two kinds of specific ethylene a-olefin copolymers or comprises a specific ethylene a-olefin copolymer and ethylene homopolymer, and a blend consisting of both the (co)polymers has a specific density and a specific melt flow rate. Hence, the polyethylene resin composition has excellent rotational moldability and can provide a rotational molded product superior to the conventional 17 polyethylene molded products in the impact resistance and the environmental stress crack resistance (ESCR) The rotational molded product according to the invention is formed from the polyethylene resin composition of the invention, and hence the molded product of the invention is superior to the conventional polyethylene molded products in the impact resistance and the environmental stress crack resistance (ESCR) Accordingly, the polyethylene resin composition for rotational molding according to the invention is suitable for the manufacture of hollow molded articles and articles of complicated shapes. More specifically, the polyethylene resin composition of the invention is suitable for the manufacture of large-sized or smallsized tanks water storage tank), containers, balls, gardening goods, furniture, machine parts, hollow molded products having special sections, outdoor goods, and the e e o e like.
EXAMPLE
Embodiment of the present invention are illustrated by reference to the following examples, but is should be •I [.construed that the invention is in no way limited to those examples.
ooeo o4oo SF-684 18 The ethylene a-olefin copolymers and the ethylene homopolymer used in the examples and the comparative examples are as follows.
Ethylene homopolymer and ethylene a-olefin copolymers prepared by single-stage polymerization Ethylene 1-hexene copolymer (M-PE(1)) Catalyst: metallocene type olefin polymerization catalyst containing zirconium Density (ASTM D 1505): 0.905 g/cm 3 10 MFR (ASTM D 1238, 1900C, load of 2.16 kg): 1 min Ethylene 1-hexene copolymer (M-PE(2)) Catalyst: metallocene type olefin polymerization catalyst containing zirconium 15 Density (ASTM D 1505): 0.905 g/cm 3 MFR (ASTM D 1238, 1900C, load of 2.16 kg): 4 min Ethylene 1-butene copolymer (Z-PE(1)) Catalyst: Ziegler type olefin polymerization catalyst Density (ASTM D 1505): 0.957 g/cm 3 MFR (ASTM D 1238, 190°C, load of 2.16 kg): 8.3 min Ethylene propylene copolymer (Z-PE(2)) SF-684 19 Catalyst: Ziegler type olefin polymerization catalyst Density (ASTM D 1505): 0.966 g/cm 3 MFR (ASTM D 1238, 190 0 C, load of 2.16 kg): 12.5 min Ethylene propylene copolymer (Z-PE(3)) Catalyst: Ziegler type olefin polymerization catalyst Density (ASTM D 1505): 0.970 g/cm 3 10 MFR (ASTM D 1238, 190 0 C, load of 2.16 kg): 16 **min m n Ethylene propylene copolymer (Z-PE(4)) Catalyst: Ziegler type olefin polymerization catalyst 15 Density (ASTM D 1505): 0.965 g/cm 3 MFR (ASTM D 1238, 190°C, load of 2.16 kg): 11 min Ethylene homopolymer Catalyst: Ziegler type olefin polymerization catalyst Density (ASTM D 1505): 0.968 g/cm 3 MFR (ASTM D 1238, 190 0 C, load of 2.16 kg): 5.2 min Ethylene 4-methyl 7 l-pentene copolymer (Z-PE(6)) SF-684 Catalyst: Ziegler type olefin polymerization catalyst Density (ASTM D 1505): 0.944 g/cm 3 MFR (ASTM D 1238, 190 0 C, load of 2.16 kg): 7.1 min Example 1 parts by weight of the ethylene 1-hexene copolymer and 70 parts by weight of the ethylene 1-butene copolymer were melt kneaded S. 10 at 200 0 C by a single screw extruder having 40 mm in diameter to prepare a polyethylene resin composition.
Then, the composition was subjected to freeze pulverization to prepare a powder having a particle diameter of not more than 30 mesh. The powder was placed 15 in a mold in the form of a cylindrical container and subjected to rotational molding at a mold temperature of 270 0 C under the molding time conditions (heating time: 8 minutes, smoothing time: 2 minutes and cooling time: minutes) to obtain a molded product (cylindrical container) having a thickness of 3 mm.
A specimen was taken from the molded product and subjected to tensile test, Olsen rigidity test, Izod impact test and environmental stress crack test in accordance with the following methods. The results are set forth in Table 1.
SF-684 21 Test method Tensile test The tensile test was carried out at a tensile rate of 50 mm/min in accordance with ASTM D-638 to measure stress at yield, tensile strength at break and elongation at break.
Olsen rigidity test The Olsen rigidity test was carried out in accordance with ASTM D-747.
10 Izod impact test The Izod impact test was carried out at -200C under the notched conditions in accordance with JIS K-7110.
Environmental stress crack test The environmental stress crack test was carried out 15 at 50 0 C using a 10% Antarox (CO-630) solution in accordance with ASTM D-1698. A sample having a thickness of 3 mm was used. The values in Table 1 show breaking time (hr).
Example 2 A polyethylene resin composition was prepared in the same manner as in Example 1, except that the ethylene 1-hexene copolymer was used in an amount of parts by weight, and 60 parts by weight of the ethylene propylene copolymer was used instead of SF-684 22 parts by weight of the ethylene 1-butene copolymer (Z- PE(1)) Then, a powder having a particle diameter of not more than 30 mesh was prepared from the polyethylene resin composition in the same manner as in Example 1, and the powder was subjected to rotational molding to obtain a molded product.
A specimen was taken from the molded product and subjected to tensile test, Olsen rigidity test, Izod impact test and environmental stress crack test in accordance with the aforesaid methods. The results are set forth in Table 1.
Example 3 A polyethylene resin composition was prepared in the same manner as in Example 1, except that the ethylene 1-hexene copolymer was used in an amount of •parts by weight, and 55 parts by weight of the ethylene propylene copolymer was used instead of parts by weight of the ethylene 1-butene copolymer (Z- PE(1)) Then, a powder having a particle diameter of not more than 30 mesh was prepared from the polyethylene resin composition in the same manner as in Example 1, and SF-684 23 the powder was subjected to rotational molding to obtain a molded product.
A specimen was taken from the molded product and subjected to tensile test, Olsen rigidity test, Izod impact test and environmental stress crack test in accordance with the aforesaid methods. The results are set forth in Table 1.
Example 4 0 10 A polyethylene resin composition was prepared in the same manner as in Example 1, except that 30 parts by weight of the ethylene 1-hexene copolymer was used instead of 30 parts by weight of the ethylene 1hexene copolymer and 70 parts by weight of the 15 ethylene propylene copolymer was used instead of 70 parts by weight of the ethylene 1-butene copolymer Then, a powder having a particle diameter of not more than 30 mesh was prepared from the polyethylene resin composition in the same manner as in Example 1, and the powder was subjected to rotational molding to obtain a molded product.
A specimen was taken from the molded product and subjected to tensile test, Olsen rigidity test, Izod impact test and environmental stress crack test in SF-684 24 accordance with the aforesaid methods. The results are set forth in Table 1.
Example A polyethylene resin composition was prepared in the same manner as in Example 1, except that the ethylene 1-hexene copolymer was used in an amount of parts by weight, and 75 parts by weight of the ethylene homopolymer was used instead of 70 parts by weight of the ethylene 1-butene copolymer Then, a powder having a particle diameter of not more than 30 mesh was prepared from the polyethylene resin composition in the same manner as in Example 1, and the powder was subjected to rotational molding to obtain 15 a molded product.
A specimen was taken from the molded product and subjected to tensile test, Olsen rigidity test, Izod impact test and environmental stress crack test in accordance with the aforesaid methods. The results are set forth in Table 1.
Example 6 In one polymerization reactor, ethylene and 1-hexene were copolymerized in the presence of a metallocene type olefin polymerization catalyst containing zirconium to SF-684 prepare an ethylene 1-hexene copolymer having a density (ASTM D 1505) of 0.904 g/cm 3 and MFR (ASTM D 1238, 1900C, load of 2.16 kg) of 1 g/10 min.
Subsequently, the ethylene 1-hexene copolymer (M- PE(3)) was introduced to another polymerization reactor connected in series to the above reactor, and in this reactor, ethylene and 1-hexene were copolymerized in the presence of a metallocene type olefin polymerization catalyst containing zirconium to prepare an ethylene 1- 10 hexene copolymer having a density (ASTM D 1505) of 0.957 g/cm 3 and MFR (ASTM D 1238, 190°C, load of 2.16 kg) of 8.8 g/10 min, whereby a polyethylene resin composition having a density (ASTM D 1505) of 0.940 g/cm 3 and MFR (ASTM D 1238, 190°C, load of 2.16 kg) of 3.9 15 min was obtained. In the resin composition, the weight ratio of the ethylene 1-hexene copolymer to the ethylene 1-hexene copolymer was 30/70.
Then, a powder having a particle diameter of not more than 30 mesh was prepared from the polyethylene resin composition in the same manner as in Example 1, and the powder was subjected to rotational molding to obtain a molded product.
A specimen was taken from the molded product and subjected to tensile test, Olsen rigidity test, Izod impact test and environmental stress crack test in SF-684 26 accordance with the aforesaid methods. The results are set forth in Table 1.
Comparative Example 1 A powder having a particle diameter of not more than mesh was prepared in the same manner as in Example 1, except that the ethylene 4-methyl-l-pentene copolymer was used instead of the polyethylene resin composition obtained in Example 1. The powder was 10 subjected to rotational molding to obtain a molded product.
A specimen was taken from the molded product and subjected to tensile test, Olsen rigidity test, Izod impact test and environmental stress crack test in accordance with the aforesaid methods. The results are set forth in Table 1.
9 9* 9* 99 99 9 9 9 9 9 f t *e 0 a 999 9 O0 oo• o• SF-684 Table 1 Ex. 1 Ex. 2 Ex. 3 Ex. 4 Ex. 5 Ex. 6 Comp.
Ex. 1 Ethylene a-olefin copolymer (A) Density (g/cm 3 0.905 0.905 0.905 0.905 0.905 0.904 MFR (g/10 min) 1 1 1 4 1 1 Ethylene homopolymer or ethylene/aolefin copolymer (B) Density (g/cm 3 0.957 0.966 0.970 0.965 0.968 0.957 MFR (g/10 min) 8.3 12.5 16 11 5.2 8.8 weight ratio in resin composition 30/70 40/60 45/55 30/70 25/75 30/70 Properties of resin composition or resin Density (g/cm 3 0.940 0.940 0.940 0.945 0.951 0.940 0.944 MFR (g/10 min) 3.6 3.2 3.2 7.8 3.4 3.9 7.1 Properties of rotational molded product Tensile properties Stress at yield (MPa) 17 19 19 19 22 17 18 Tensile strength at break (MPa) 32 30 33 28 28 33 26 Elongation at break 860 750 760 900 820 890 760 Olsen rigidity (MPa) 420 430 420 490 680 420 500 Izod impact strength >690 NB >690 83 >690 >690 ESCR (hr) >600 >600 >600 93 >600 >600 16 The resin compositions of Examples 1 to and the component (B) 5 are each a melt blend of the component (A) The resin composition of Example 6 is a resin composition obtained by continuously carrying out preparation of the component and preparation of the component "NB" in the table indicates that the specimen was not broken in the impact test.
28 Throughout this specification and the claims which follow, unless the context requires otherwise, the word "comprise", and variations such as "comprises" and "comprising", will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps.
The reference to any prior art in this specification is not, and should not be taken as, an acknowledgment or any form of suggestion that that prior art forms part of the common general knowledge in Australia.
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Claims (8)
1. A polyethylene resin composition for rotational molding, comprising: an ethylene a-olefin copolymer which comprises ethylene and an a-olefin of 3 to 20 carbon atoms and which has a density (ASTM D1505) of 0.880 to 0.930 g/cm 3 and a melt flow rate (MFR) (ASTM D 1238, 190 0 C, load: 2.16 Kg) of 0.01 to 5 g/10 min, and an ethylene homopolymer which comprises ethylene or an ethylene a-olefin copolymer which comprises ethylene and an c-olefin of 3 to 20 carbon atoms, which has a density (ASTM D 1505) of 0.931 to 0.974 g/cm 3 and a melt flow rate (MFR) (ASTM D 1238, 1900, load: 2.16 kg) of 0.5 to 20 min, wherein: the weight ratio of the ethylene a-olefin o* 9 copolymer to the ethylene homopolymer or the ethylene olefin copolymer has a density (ASTM D 1505) of 0.920 to S 20 0.960 g/cm 3 and a melt flow rate (MFR) (ASTM D 1238, 190 0 C, :load: 2.16 kg) of 1 to 10 g/10 min.
2. The composition as claimed in claim 1, wherein the ethylene a-olefin copolymer the ethylene homopolymer 25 and the ethylene a-olefin copolymer are prepared by the use of a metallocene type olefin polymerization catalyst.
3. The composition as claimed in claim 1, wherein the ethylene a-olefin copolymer is prepared by the use of a metallocene type olefin polymerization catalyst, and the ethylene homopolymer and the ethylene a-olefin P;\OPERcc\48619-00 spaldoc-08/07/03 copolymer are prepared by the use of a Ziegler type olefin polymerization catalyst.
4. The composition as claimed in claim 1, wherein the ethylene c-olefin copolymer the ethylene homopolymer and the ethylene a-olefin copolymer are prepared by the use of a Ziegler type olefin polymerization catalyst.
The composition as claimed in claim 1, wherein the ethylene a-olefin copolymer is prepared by the use of a Ziegler type olefin polymerization catalyst, and the ethylene homopolymer and the ethylene a-olefin copolymer are prepared by the use of a metallocene type olefin polymerization catalyst.
6. The composition as claimed in any one of claims 1 to 5, in the form of a powder having a particle diameter of not more than 30 mesh. 20
7. A polyethylene resin composition as claimed in claim 1 substantially as hereinbefore described with reference to the examples.
8. A rotational molded product comprising the rotational 25 molding polyethylene resin composition as claimed in any one of claims 1 to 7. oe9. Dated this 8 t h day of July 2003 Mitsui Chemicals, Inc. by DAVIES COLLISON CAVE Patent Attorneys for the Applicant(s)
Applications Claiming Priority (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP20267899 | 1999-07-16 | ||
| JP11-202678 | 1999-07-16 | ||
| JP2000194925A JP2001089615A (en) | 1999-07-16 | 2000-06-23 | Rotational molding polyethylene resin composition and rotational molding product using the same composition |
| JP12-194925 | 2000-06-23 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| AU4861900A AU4861900A (en) | 2001-01-18 |
| AU764796B2 true AU764796B2 (en) | 2003-08-28 |
Family
ID=26513522
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| AU48619/00A Ceased AU764796B2 (en) | 1999-07-16 | 2000-07-14 | Polyethylene resin composition for rotational molding and rotational molded product using the composition |
Country Status (5)
| Country | Link |
|---|---|
| JP (1) | JP2001089615A (en) |
| CN (1) | CN1284822C (en) |
| AU (1) | AU764796B2 (en) |
| NZ (1) | NZ505712A (en) |
| TW (1) | TW593500B (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7230054B2 (en) | 2004-06-29 | 2007-06-12 | Equistar Chemicals, Lp | Polymer resins with improved environmental stress crack resistance |
| US8372329B1 (en) | 2004-05-28 | 2013-02-12 | Total Petrochemicals Research Feluy | Use of thermoplastic composition comprising polyether-block copolyamides as additive |
| EP2681273B1 (en) | 2011-03-04 | 2017-08-23 | Total Research & Technology Feluy | Process for preparing polyethylene blend comprising metallocene produced resins and ziegler-natta produced resins |
| US12134213B2 (en) | 2018-03-22 | 2024-11-05 | Dow Global Technologies Llc | Process for forming a rotational molded article |
Families Citing this family (22)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7943700B2 (en) | 2002-10-01 | 2011-05-17 | Exxonmobil Chemical Patents Inc. | Enhanced ESCR of HDPE resins |
| US7396881B2 (en) | 2002-10-01 | 2008-07-08 | Exxonmobil Chemical Patents Inc. | Polyethylene compositions for rotational molding |
| US7396878B2 (en) | 2002-10-01 | 2008-07-08 | Exxonmobil Chemical Patents Inc. | Polyethylene compositions for injection molding |
| CA2498087A1 (en) | 2002-10-01 | 2004-04-15 | Exxonmobil Chemical Patents Inc. | Polyethylene compositions for rotational molding |
| JP5832098B2 (en) * | 2003-02-17 | 2015-12-16 | 三井化学株式会社 | Application to ethylene polymers and molded products |
| JP4231309B2 (en) * | 2003-03-14 | 2009-02-25 | リケンテクノス株式会社 | Method for producing sol-like thermoplastic resin composition |
| EP1600477A1 (en) * | 2004-05-28 | 2005-11-30 | Total Petrochemicals Research Feluy | Use of thermoplastic composition comprising polyethylene glycol as additive |
| EP1600474A1 (en) * | 2004-05-28 | 2005-11-30 | Total Petrochemicals Research Feluy | Use of fluoropolymers for rotomolding |
| EP1600476A1 (en) * | 2004-05-28 | 2005-11-30 | Total Petrochemicals Research Feluy | Use of polyetheresters for rotomolding |
| EP1600478A1 (en) * | 2004-05-28 | 2005-11-30 | Total Petrochemicals Research Feluy | Use of thermoplastic composition comprising thermoplastic polyurethanes as additive |
| BR112012003539A2 (en) | 2009-08-28 | 2017-05-23 | Dow Global Technologies Llc | rotational molded article and process for manufacturing an article |
| CN101844654B (en) * | 2010-04-13 | 2012-01-18 | 无锡新龙科技有限公司 | Manufacturing process of storage tank with plastic steel composite structure |
| CN103665505A (en) * | 2012-08-29 | 2014-03-26 | 中国石油化工股份有限公司 | Ethylene polymer composition, ethylene polymer material and fruit milk bottle |
| CN103665528B (en) * | 2012-09-20 | 2015-12-02 | 中国石油化工股份有限公司 | Be applicable to polyolefine resin composition of rotation molding processing and preparation method thereof |
| CA2834068C (en) * | 2013-11-18 | 2020-07-28 | Nova Chemicals Corporation | Enhanced escr bimodal rotomolding resin |
| CN105131411B (en) * | 2015-08-27 | 2017-07-18 | 浙江瑞堂塑料科技有限公司 | A kind of rotation molding urea box polythene material and preparation method thereof |
| CN108794869B (en) * | 2017-04-28 | 2021-04-13 | 中国石油化工股份有限公司 | Polyolefin composition for rotational molding storage tank and preparation method thereof |
| CN111073119A (en) * | 2018-10-18 | 2020-04-28 | 中国石油化工股份有限公司 | Assistant composition, linear medium-density polyethylene composition, preparation method thereof and polyethylene rotational molding product |
| MX2022008506A (en) * | 2020-02-17 | 2022-08-08 | Nova Chem Int Sa | Rotomolding composition. |
| US11746220B2 (en) | 2020-06-12 | 2023-09-05 | Braskem S.A. | High flow rotomolding compositions, processes thereof, and articles therefrom |
| EP4477680A3 (en) * | 2020-06-30 | 2025-03-19 | Dow Global Technologies LLC | Polyethylene compositions |
| CN119431641A (en) * | 2024-12-02 | 2025-02-14 | 中国石油化工股份有限公司 | Polyethylene resin for rotational molding and preparation method and application thereof |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0272603A (en) * | 1988-09-08 | 1990-03-12 | Tamagawa Seiki Co Ltd | Core |
| JPH04120107A (en) * | 1990-09-10 | 1992-04-21 | Mitsui Petrochem Ind Ltd | Ethylene/pentene-1 copolymer for rotational molding and rotationally molded material |
| JP2000007849A (en) * | 1998-04-23 | 2000-01-11 | Mitsui Chemicals Inc | Polyethylene resin and its production |
-
2000
- 2000-06-23 JP JP2000194925A patent/JP2001089615A/en active Pending
- 2000-07-06 TW TW89113425A patent/TW593500B/en not_active IP Right Cessation
- 2000-07-12 NZ NZ50571200A patent/NZ505712A/en unknown
- 2000-07-14 AU AU48619/00A patent/AU764796B2/en not_active Ceased
- 2000-07-14 CN CN 00120777 patent/CN1284822C/en not_active Expired - Lifetime
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0272603A (en) * | 1988-09-08 | 1990-03-12 | Tamagawa Seiki Co Ltd | Core |
| JPH04120107A (en) * | 1990-09-10 | 1992-04-21 | Mitsui Petrochem Ind Ltd | Ethylene/pentene-1 copolymer for rotational molding and rotationally molded material |
| JP2000007849A (en) * | 1998-04-23 | 2000-01-11 | Mitsui Chemicals Inc | Polyethylene resin and its production |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8372329B1 (en) | 2004-05-28 | 2013-02-12 | Total Petrochemicals Research Feluy | Use of thermoplastic composition comprising polyether-block copolyamides as additive |
| US7230054B2 (en) | 2004-06-29 | 2007-06-12 | Equistar Chemicals, Lp | Polymer resins with improved environmental stress crack resistance |
| EP2681273B1 (en) | 2011-03-04 | 2017-08-23 | Total Research & Technology Feluy | Process for preparing polyethylene blend comprising metallocene produced resins and ziegler-natta produced resins |
| US12134213B2 (en) | 2018-03-22 | 2024-11-05 | Dow Global Technologies Llc | Process for forming a rotational molded article |
Also Published As
| Publication number | Publication date |
|---|---|
| CN1281003A (en) | 2001-01-24 |
| AU4861900A (en) | 2001-01-18 |
| NZ505712A (en) | 2002-02-01 |
| TW593500B (en) | 2004-06-21 |
| JP2001089615A (en) | 2001-04-03 |
| CN1284822C (en) | 2006-11-15 |
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