NZ505712A - 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 compositionInfo
- Publication number
- NZ505712A NZ505712A NZ50571200A NZ50571200A NZ505712A NZ 505712 A NZ505712 A NZ 505712A NZ 50571200 A NZ50571200 A NZ 50571200A NZ 50571200 A NZ50571200 A NZ 50571200A NZ 505712 A NZ505712 A NZ 505712A
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- New Zealand
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- ethylene
- resin composition
- copolymer
- olefin
- rotational
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Abstract
A polyethylene resin composition for rotational moulding and a rotational moulded product using a composition is provided. The composition comprises an ethylene-á-olefin copolymer (A) having a density of 0.880-0.093 g/cm3 and a melt index (MFR) of 0.01-5.0 g/10 min and an ethylene homopolymer or an ethylene-á-olefin copolymer (B) having a density of 0.931-0.974 g/cm3 and MFR of 0.5-20 g/10 min, wherein the weight gain ((A)/(B)) of component (A) to component (B) is in the range of 10/90 to 50/50, and a blend consisting of these components (A) and (B) has a density of 0.920-0.960 g/cm3 and MFR of 1-10 g/10 min. The component (A) is a copolymer prepared by the use of a metallocene type olefin polymerisation catalyst, and component (B) is a copolymer prepared by the use of a metallocene type or Ziegler type olefin polymerisation catalyst.
Description
New Zealand Paient Spedficaiion for Paient Number 505712
Patents Form No. 5
Our Ref- GL213889
Patents Act 1953
COMPLETE SPECIFICATION
POLYETHYLENE RESIN COMPOSITION FOR ROTATIONAL MOLDING AND ROTATIONAL MOLDED PRODUCT USING THE COMPOSITION
We, MITSUI CHEMICALS, INC., a legal entity of Japan, of 2-5, Kasumigaseki 3-chome, Chiyoda-ku, Tokyo 100-6070, Japan hereby declare the invention, for which we pray that a patent may be granted to us and the method by which it is to be performed, to be particularly described in and by the following statement:
IWILLLECIUAL PhC:G;T7 OF • OF NZ
PT05A81293
1 2 JUL 2000 R E C *r IV f O
(followed by page 1a)
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TTTLE
POLYETHYLENE RESIN COMPOSITION FOR ROTATIONAL MOLDING AND ROTATIONAL MOLDED PRODUCT USING THE COMPOSITION
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 10 suitable for the manufacture of hollow molded articles or 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 20 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, 25 particularly in impact resistance and environmental
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stress crack resistance (ESCR). As a rotational molding material that meets such needs, a polyethylene resin has been mainly employed.
The articles obtained by rotational molding of the 5 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.
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^, a melt index (MFR) of 1 to 20 g/10 min and a molecular 15 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 20 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 25 stress crack resistance (ESCR) is now desired.
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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 5 environmental stress crack resistance can be obtained by rotational molding of a resin composition which comprises (A) 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^ and a melt 10 flow rate (ASTM D 1238, 190°C, load of 2.16 kg) of 0.01 to 5 g/10 min and (B) 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/cm3 and a melt flow 15 rate of 0.5 to 20 g/10 min, wherein the (A)/(B) weight ratio is in the specific range and a blend consisting of the ethylene - a-olefin copolymer (A) and the ethylene homopolymer or the ethylene - a-olefin copolymer (B) has a density of 0.920 to 0.960 g/cm3 and a melt flow rate of 20 1 to 10 g/10 min. Based on the finding, the present invention has been accomplished.
OBJECT OF THE INVENTION It is an object of the present invention to provide 25 a polyethylene resin composition for rotational molding
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from 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 , or to at least provide a useful alternative composition or product.
SUMMARY OF THF, INVENTION The polyethylene resin composition for rotational molding according to the present invention is a resin
composition comprising:
(A) 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/cm3 and a melt flow rate (MFR) (ASTM D 1238, 190°C, load:
2.16 kg) of 0.01 to 5 g/10 min, and
(B) an ethylene homopolymer comprising ethylene or an ethylene - a-olefin copolymer comprising 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/cm3 and a melt flow
rate (MFR) (ASTM D 1238, 190°C, load: 2.16 kg) of 0.5 to 20 g/10 min,
wherein:
the weight ratio ((A)/(B)) of the ethylene - a-olefin copolymer (A) to the ethylene homopolymer or the
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ethylene - a-olefin copolymer (B) is in the range of 10/90 to 50/50, and a blend consisting of the ethylene - a-olefin copolymer (A) and the ethylene homopolymer or the 5 ethylene - a-olefin copolymer (B) has a density (ASTM D 1505) of 0.920 to 0.960 g/cm3 and a melt flow rate (MFR) (ASTM D 1238, 190°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 (A), the ethylene homopolymer (B) and the ethylene - a-olefin copolymer (B) ;
(1) a resin composition wherein the ethylene - a-
olefin copolymer (A), the ethylene homopolymer (B) and the ethylene - a-olefin copolymer (B) are each a (co)polymer prepared by the use of a metallocene type olefin polymerization catalyst;
(2) a resin composition wherein the ethylene - a-
olefin copolymer (A) is a copolymer prepared by the use of a metallocene type olefin polymerization catalyst, and the ethylene homopolymer (B) and the ethylene - a-olefin copolymer (B) are prepared by the use of a Ziegler type 25 olef m polymerization catalyst;
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(3) a resin composition wherein the ethylene - a-olefin copolymer (A), the ethylene homopolymer (B) and the ethylene - a-olefin copolymer (B) are prepared by the use of a Ziegler type olefin polymerization catalyst; and 5 (4) a resin composition wherein the ethylene - a-
olefin copolymer (A) is prepared by the use of a Ziegler type olefin polymerization catalyst, and the ethylene homopolymer (B) 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 (1) to (4), preferable are the resin compositions (1) and (2) 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 (B) prepared by the use of a metallocene type or Ziegler type olefin polymerization catalyst. In particular, a composition comprising the ethylene - a-olefin copolymer (A) prepared 20 by the use of a metallocene type olefin polymerization catalyst and the ethylene homopolymer or the ethylene -a-olefin copolymer (B) prepared by the use of a Ziegler type olefin polymerization catalyst is preferable.
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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 (A) and an ethylene homopolymer or an ethylene - a-olefin copolymer (B) having a density different from that of the copolymer (A), and when the 15 resin composition consists of the ethylene - a-olefin copolymer (A) and the ethylene homopolymer or the ethylene - a-olefin copolymer (B), 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 (A) for use in the invention is a copolymer of ethylene and an a-olefin of 3 to 20 carbon atoms, and has a density (ASTM D 1505) of 0.880 to 0.930 g/cm3, preferably 0.885 to 0.925 g/cm3, 25 more preferably 0.890 to 0.920 g/cm3, and a melt flow
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rate (MFR) (ASTM D 1238, 190°C, load: 2.16 kg) of 0.01 to 5 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 5 include propylene, 1-butene, 1-pentene, 2-methyl-l-butene, 3-methyl-l-butene, 1-hexene, 3-methyl-l-pentene, 4-methyl-l-pentene, 3,3-dimethyl-l-butene, 1-heptene, methyl-l-hexene, dimethyl-l-pentene, trimethyl-l-butene, ethyl-l-pentene, 1-octene, methyl-l-pentene, dimethyl-1-10 hexene, trimethyl-l-pentene, ethyl-l-hexene, methylethyl-1-pentene, diethyl-l-butene, propyl-l-pentene, 1-decene, methyl-l-nonene, dimethyl-l-octene, trimethyl-l-heptene, ethyl-l-octene, methylethyl-l-heptene, diethyl-l-hexene, 1-dodecene and 1-hexadodecene.
These a-olefins can be used singly or in combination of two or more kinds.
The ethylene - a-olefin copolymer (A) preferably used in the invention is an ethylene - 1-butene copolymer, an ethylene - 1-pentene copolymer, an ethylene - 1-hexene 20 copolymer, an ethylene - 4-methyl-l-pentene copolymer or an ethylene - 1-octene copolymer.
The ethylene - a-olefin copolymer (A) having the above properties can be prepared by copolymerizing ethylene and an a-olefin of 3 to 20 carbon atoms in the 25 presence of a conventional Ziegler type or metallocene
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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 5 copolymer (B) for use in the invention is a polymer of only ethylene or a copolymer of ethylene and an a-olefin of 3 to 20 carbon atoms, and has a density (ASTM D 1505) of 0.931 to 0.974 g/cm3, preferably 0.935 to 0.970 g/cm3, more preferably 0.938 to 0.968 g/cm3, and a melt flow 10 rate (MFR) (ASTM D 1238, 190°C, load: 2.16 kg) of 0.5 to 20 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 of 3 to 20 carbon atoms include the same a-olefins of 3 to 20 carbon atoms as 15 used for constituting the aforesaid ethylene - a-olefin copolymer (A). The a-olefins of 3 to 20 carbon atoms can be used singly or in combination of two or more kinds.
The ethylene - a-olefin copolymer (B) preferably used in the invention is an ethylene - 1-butene copolymer, 20 an ethylene - 1-pentene copolymer, an ethylene - 1-hexene copolymer, an ethylene - 4-methyl-l-pentene copolymer or an ethylene - 1-octene copolymer.
The ethylene homopolymer or the ethylene - a-olefin copolymer (B) having the above properties can be prepared 25 by homopolymerizing ethylene or copolymerizing ethylene
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and an a-olefin of 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 (B), or an ethylene homopolymer or the ethylene - a-olefin 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 (B) .
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 (A), 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-olefin copolymer (A) prepared by the use of a metallocene type olefin polymerization catalyst and the
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ethylene homopolymer (component (B)) prepared by the use of a Ziegler type olefin polymerization catalyst is preferable.
Polyethylene resin composition for rotational molding 5 The polyethylene resin composition for rotational molding according to the invention comprises the ethylene - a-olefin copolymer (A) and the ethylene homopolymer or the ethylene - a-olefin copolymer (B).
In the resin composition, the weight ratio ((A)/(B)) 10 of the ethylene - a-olefin copolymer (A) to the ethylene homopolymer or the ethylene - a-olefin copolymer (B) 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 15 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 (B) has a density (ASTM D 1505) of 0.920 to 0.960 g/cm3, preferably 0.922 to 0.958 g/cm3, more 20 preferably 0.925 to 0.955 g/cm3, particularly preferably 0.930 to 0.955 g/cm3, and a melt flow rate (MFR) (ASTM D 1238, 190°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 g/10 min. When the density of the resin composition is 25 m the above range, a rotational molded product having
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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 5 polyethylene rotational molded product having good appearance can be obtained.
Preparation of polyethylene resin composition for rotational molding
The polyethylene resin composition for rotational 10 molding according to the invention comprises the ethylene - a-olefin copolymer (A) and the ethylene homopolymer or the ethylene - a-olefin copolymer (B), as described above.
To the polyethylene resin composition, additives,
such as organic or inorganic filler, antioxidant, heat 15 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.
The polyethylene resin composition for rotational 20 molding according to the invention may be in the form of a powder or pellets, and the composition needs to be only m the form of a powder when subjected to rotational molding.
When the polyethylene resin composition for 25 rotational molding according to the invention is in the
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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 5 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. 10 The polyethylene resin composition for rotational molding according to the invention can be obtained by melt kneading the ethylene - a-olefin copolymer (A), the ethylene homopolymer or the ethylene - a-olefin copolymer (B), 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 20 rotational molding according to the invention can be obtained also by continuously carrying out a step of copolymerizing ethylene and an a-olefin of 3 to 20 carbon atoms m the presence of a metallocene type olefin polymerization catalyst_ to prepare the ethylene - a-25 olefin copolymer (A) and a step of homopolymerizing
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ethylene or copolymerizing ethylene and an a-olefin of 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 5 copolymer (B) 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 (A) and the ethylene homopolymer or the ethylene - a-olefin copolymer (B) 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 of 3 to 20 carbon atoms in the presence of a Ziegler type olefin polymerization catalyst to prepare the ethylene - a-olefin copolymer (A) and a step of homopolymerizing 20 ethylene or copolymerizing ethylene and an a-olefin of 3 to 20 carbon atoms in the presence of a Ziegler type olefin polymerization catalyst to prepare the ethylene homopolymer or the ethylene - a-olefin copolymer (B) and then powdering the resulting resin composition by means 25 of freeze pulverization or mechanical pulverization.
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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 a-olefin of 3 to 20 carbon atoms in the presence of a Ziegler type olefin polymerization catalyst to prepare the ethylene - a-olefin copolymer (A) and a step of homopolymerizing ethylene or copolymerizing ethylene and an a-olefin of 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 (B) 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.
Rotational molded product
The rotational molded product according to the invention is produced by rotational molding of the above-described polyethylene resin composition for rotational molding. The polyethylene resin composition subjected to rotational molding is in the form of a powder, as described above.
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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 5 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 10 of the mold is taken out. Thus, the rotational molded product of the invention can be obtained.
The inside surface of the mold may have embossed patterns, or it need not have.
EFFECT OF THE INVENTTON
The polyethylene resin composition for rotational molding according to the invention comprises two kinds of specific ethylene - a-olefin copolymers or ^compri^ses 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
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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 5 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 10 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 small-15 sized tanks (e.g., water storage tank), containers, balls, gardening goods, furniture, machine parts, hollow molded products having special sections, outdoor goods, and the like.
EXAMPLE
The present invention is further described with reference to the following examples, but it should be construed that the invention is in no way limited to those examples.
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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 5 prepared by single-stage polymerization
(1) Ethylene - 1-hexene copolymer (M-PE(l))
Catalyst: metallocene type olefin polymerization catalyst containing zirconium
Density (ASTM D 1505): 0.905 g/cm3 10 MFR (ASTM D 1238, 190°C, load of 2.16 kg): 1 g/10
min
(2) Ethylene - 1-hexene copolymer (M-PE(2))
Catalyst: metallocene type olefin polymerization catalyst containing zirconium 15 Density (ASTM D 1505): 0.905 g/cm3
MFR (ASTM D 1238, 190°C, load of 2.16 kg): 4 g/10
min
(3) Ethylene - 1-butene copolymer (Z-PE(l))
Catalyst: Ziegler type olefin polymerization 20 catalyst
Density (ASTM D 1505): 0.957 g/cm3
MFR (ASTM D 1238, 190°C, load of 2.16 kg): 8.3 g/10
min
(4) Ethylene - propylene copolymer (Z-PE(2))
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Catalyst: Ziegler type olefin polymerization catalyst
Density (ASTM D 1505): 0.966 g/cm3
MFR (ASTM D 1238, 190°C, load of 2.16 kg): 12.5 g/10
min
(5) Ethylene - propylene copolymer (Z-PE(3))
Catalyst: Ziegler type olefin polymerization catalyst
Density (ASTM D 1505): 0.970 g/cm3
MFR (ASTM D 1238, 190°C, load of 2.16 kg): 16 g/10
min
(6) Ethylene - propylene copolymer (Z-PE(4))
Catalyst: Ziegler type olefin polymerization catalyst
Density (ASTM D 1505): 0.965 g/cm3
MFR (ASTM D 1238, 190°C, load of 2.16 kg): 11 g/10
min
(7) Ethylene homopolymer (Z-PE(5))
Catalyst: Ziegler type olefin polymerization catalyst
Density (ASTM D 1505): 0.968 g/cm3
MFR (ASTM D 1238, 190°C, load of 2.16 kg): 5.2 g/10
min
(8) Ethylene - 4-methyl-l-pentene copolymer (Z-PE(6))
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Catalyst: Ziegler type olefin polymerization catalyst
Density (ASTM D 1505): 0.944 g/cm3
MFR (ASTM D 1238, 190°C, load of 2.16 kg): 7.1 g/10
min
Fxample 1
parts by weight of the ethylene - 1-hexene copolymer (M-PE(l)) and 70 parts by weight of the ethylene - 1-butene copolymer (Z-PE(l)) were melt kneaded 10 at 200°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 27 0°C under the molding time conditions (heating time: 8 minutes, smoothing time: 2 minutes and cooling time: 5 minutes) to obtain a molded product (cylindrical 20 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 25 set forth in Table 1.
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Test method
(1) Tensile test
The tensile test was carried out at a tensile rate of 50 mm/min in accordance with ASTM D-638 to measure 5 stress at yield, tensile strength at break and elongation at break.
(2) Olsen rigidity test
The Olsen rigidity test was carried out in accordance with ASTM D-747.
(3) Izod impact test
The Izod impact test was carried out at -20°C under the notched conditions in accordance with JIS K-7110.
(4) Environmental stress crack test
The environmental stress crack test was carried out 15 at 50°C using a 10% Antarox (C0-630) solution in accordance with ASTM D-1698. A sample having a thickness of 3 mm was used. The values in Table 1 show 50%
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 (M-PE(l)) was used in an amount of 40 parts by weight, and 60 parts by weight of the ethylene -25 propylene copolymer (Z-PE(2)) was used instead of 70
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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 5 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 10 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 (M-PE(l)) was used in an amount of 45 parts by weight, and 55 parts by weight of the ethylene -propylene copolymer (Z-PE(3)) was used instead of 70 20 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
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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 5 impact test and environmental stress crack test in accordance with the aforesaid methods. The results are set forth in Table 1.
Example 4
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 (M-PE(2)) was used instead of 30 parts by weight of the ethylene - 1-hexene copolymer (M-PE(l)), and 70 parts by weight of the 15 ethylene - propylene copolymer (Z-PE(4)) was used instead of 70 parts by weight of the ethylene - 1-butene copolymer (Z-PE(l)).
Then, a powder having a particle diameter of not more than 30 mesh was prepared from the polyethylene 20 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 25 impact test and environmental stress crack test m
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accordance with the aforesaid methods. The results are set forth in Table 1.
Example 5
A polyethylene resin composition was prepared in the same manner as in Example 1, except that the ethylene -1-hexene copolymer (M-PE(l)) was used in an amount of 25 parts by weight, and 75 parts by weight of the ethylene homopolymer (Z-PE(5)) was used instead of 70 parts by 10 weight of the ethylene - 1-butene copolymer (Z-PE(l)).
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 20 set forth in Table 1.
Example 6
In one polymerization reactor, ethylene and 1-hexene were copolymerized in the presence of a metallocene type 25 olef in polymerization catalyst containing zirconium to
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prepare an ethylene - 1-hexene copolymer (M-PE(3)) having a density (ASTM D 1505) of 0.904 g/cm3 and MFR (ASTM D 1238, 190°C, load of 2.16 kg) of 1 g/10 min.
Subsequently, the ethylene - 1-hexene copolymer (M-5 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 (M-PE(4)) having a density (ASTM D 1505) of 0.957 g/cm3 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/cm3 and MFR (ASTM D 1238, 190°C, load of 2.16 kg) of 3.9 g/10 15 min was obtained. In the resin composition, the weight ratio of the ethylene - 1-hexene copolymer (M-PE(3)) to the ethylene - 1-hexene copolymer (M-PE(4)) was 30/70.
Then, a powder having a particle diameter of not more than 30 mesh was prepared from the polyethylene 20 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 25 impact test and environmental stress crack test m
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 30 mesh was prepared in the same manner as in Example 1, except that the ethylene - 4-methyl-l-pentene copolymer (Z-PE(6)) was used instead of the polyethylene resin composition obtained in Example 1. 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.
Claims (8)
1. A polyethylene resin composition>for rotational moldingT) comprising: (A) an ethylene - a-olefin copolymer comprising 5 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/cm3 and a melt flow rate (MFR) (ASTM D 1238, 190°C, load: 2.16 kg) of 0.01 to 5 g/10 min, and (B) an ethylene homopolymer comprising ethylene or 10 an ethylene - a-olefin copolymer comprising 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/cm3 and a melt flow rate (MFR) (ASTM D 1238, 190°C, load: 2.16 kg) of 0.5 to 20 g/10 min, 15 wherein: the weight ratio ((A)/(B)) of the ethylene - a-olefin copolymer (A) to the ethylene homopolymer or the ethylene - a-olefin copolymer (B) is in the range of 10/90 to 50/50, and 20 a blend consisting of the ethylene - a-olefin copolymer (A) and the ethylene homopolymer or the ethylene - a-olefin copolymer (B) has a density (ASTM D 1505) of 0.920 to 0.960 g/cm3 and a melt flow rate (MFR) (ASTM D 1238, 190°C, load: 2.16 kg) of 1 to 10 g/10 min. 25 SF-684 29
2. The polyethylene resin composition for rotational molding as claimed in claim 1, wherein the ethylene - a-olefin copolymer (A), the ethylene homopolymer (B) and the ethylene - a-olefin copolymer (B) 5 are prepared by the use of a metallocene type olefin polymerization catalyst.
3. The polyethylene resin composition for rotational molding as claimed in claim 1, wherein the 10 ethylene - a-olefin copolymer (A) is prepared by the use of a metallocene type olefin polymerization catalyst, and the ethylene homopolymer (B) and the ethylene - a-olefin copolymer (B) are prepared by the use of a Ziegler type olefin polymerization catalyst. 15
4. The polyethylene resin composition for rotational molding as claimed in claim 1, wherein the ethylene - a-olefin copolymer (A), the ethylene homopolymer (B) and the ethylene - a-olefin copolymer (B) 20 are prepared by the use of a Ziegler type olefin polymerization catalyst.
5. The polyethylene resin composition for rotational molding as claimed in claim 1, wherein the 25 ethylene - a-olefin copolymer (A) is prepared by the use SF-684 30 of a Ziegler type olefin polymerization catalyst, and the ethylene homopolymer (B) and the ethylene - a-olefin "copolymer (B) are prepared by the use of a metallocene type olefin polymerization catalyst.
6. The polyethylene resin composition for rotational molding as claimed in any one of claims 1 to 5, wherein the powder of said polyethylene resin composition has a particle diameter of not more than 30 mesh.
7. A rotational molded product comprising the rotational molding polyethylene resin composition of any one of claims 1 to 6.
8. A polyethylene resin composition substantially as herein described with reference to any one of the Examples. 9 A rotational molded product substantially as herein described with reference to any one of the Examples. 5 10 SF-684 ABSTRACT The polyethylene resin composition for rotational molding according to the invention is a composition comprising an ethylene - a-olefin copolymer (A) having a 5 density of 0.880 to 0.930 g/cm3 and MFR of 0.01 to 5 g/10 min and an ethylene homopolymer or an ethylene - a-olefin copolymer (B) having a density of 0.931 to 0.974 g/cm3 and MFR of 0.5 to 20 g/10 min, wherein the weight ratio ((A)/(B)) of the component (A) to the component (B) is in 10 the range of 10/90 to 50/50, and a blend consisting of these components (A) and (B) has a density of 0.920 to 0.960 g/cm3 and MFR of 1 to 10 g/10 min. The component (A) is preferably a copolymer prepared by the use of a metallocene type olefin polymerization catalyst, and the 15 component (B) is preferably a (co)polymer prepared by the use of a metallocene type or Ziegler type olefin polymerization catalyst. The rotational molded product of the invention comprises the polyethylene resin composition. According to the invention, a polyethylene 20 resin composition for rotational molding which has excellent rotational moldability and is capable of producing rotational molded products superior to the conventional polyethylene rotational molded products in impact resistance and environmental stress crack SF-684 resistance, and a rotational molded product using the composition can be provided.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP20267899 | 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 |
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| Publication Number | Publication Date |
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| NZ505712A true NZ505712A (en) | 2002-02-01 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| NZ50571200A NZ505712A (en) | 1999-07-16 | 2000-07-12 | 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) |
Families Citing this family (23)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7396878B2 (en) | 2002-10-01 | 2008-07-08 | Exxonmobil Chemical Patents Inc. | Polyethylene compositions for injection molding |
| 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 |
| BR0314857A (en) | 2002-10-01 | 2005-08-02 | Exxonmobil Chemical Patentes I | Rotational Molding Polyethylene Compositions |
| 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 |
| EP1600476A1 (en) * | 2004-05-28 | 2005-11-30 | Total Petrochemicals Research Feluy | Use of polyetheresters for rotomolding |
| EP1600475A1 (en) | 2004-05-28 | 2005-11-30 | Total Petrochemicals Research Feluy | Use of Thermoplastic Composition Comprising Polyether-Block Copolyamides as Additive |
| 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 |
| EP1600478A1 (en) * | 2004-05-28 | 2005-11-30 | Total Petrochemicals Research Feluy | Use of thermoplastic composition comprising thermoplastic polyurethanes as additive |
| US7230054B2 (en) | 2004-06-29 | 2007-06-12 | Equistar Chemicals, Lp | Polymer resins with improved environmental stress crack resistance |
| MY162909A (en) | 2009-08-28 | 2017-07-31 | Univation Tech Llc | Rotational molded articles, and method of making the same |
| 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 |
| PL2681273T3 (en) | 2011-03-04 | 2018-01-31 | Total Res & Technology Feluy | Process for preparing polyethylene blend comprising metallocene produced resins and ziegler-natta produced resins |
| 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 |
| EP3768485B1 (en) * | 2018-03-22 | 2023-11-22 | Dow Global Technologies LLC | Process for forming a rotational molded article and rotational molded article |
| 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 |
| US11746220B2 (en) | 2020-06-12 | 2023-09-05 | Braskem S.A. | High flow rotomolding compositions, processes thereof, and articles therefrom |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| JP2821480B2 (en) * | 1988-09-08 | 1998-11-05 | 多摩川精機株式会社 | Rotor core |
| JP2967937B2 (en) * | 1990-09-10 | 1999-10-25 | 三井化学株式会社 | Rotational molding |
| 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
Also Published As
| Publication number | Publication date |
|---|---|
| TW593500B (en) | 2004-06-21 |
| CN1284822C (en) | 2006-11-15 |
| CN1281003A (en) | 2001-01-24 |
| AU764796B2 (en) | 2003-08-28 |
| AU4861900A (en) | 2001-01-18 |
| JP2001089615A (en) | 2001-04-03 |
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