CA1120630A - Pipe extrusion polymeric blend - Google Patents
Pipe extrusion polymeric blendInfo
- Publication number
- CA1120630A CA1120630A CA000312081A CA312081A CA1120630A CA 1120630 A CA1120630 A CA 1120630A CA 000312081 A CA000312081 A CA 000312081A CA 312081 A CA312081 A CA 312081A CA 1120630 A CA1120630 A CA 1120630A
- Authority
- CA
- Canada
- Prior art keywords
- copolymer
- polymer blend
- ethylene
- density
- condition
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
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- Extrusion Moulding Of Plastics Or The Like (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
A polymeric blend composition suitable for both dynamic and screw extrusion said composition comprising an ethylene hexene copolymer having a density of about 0.936 to about 0.940 and a melt index of about 0.30 to about 0.45 (ASTM D 1238-65T, condition E) and a copolymer chosen from an ethylene butene copolymer having a density of about 0.940 to about 0.942 and a high load melt index of about 0 to about 2(ASTM D 1238065T, condition F) and a high load melt index of about 3 to about 5 (ASTM D 1238-65T, condition F).
A polymeric blend composition suitable for both dynamic and screw extrusion said composition comprising an ethylene hexene copolymer having a density of about 0.936 to about 0.940 and a melt index of about 0.30 to about 0.45 (ASTM D 1238-65T, condition E) and a copolymer chosen from an ethylene butene copolymer having a density of about 0.940 to about 0.942 and a high load melt index of about 0 to about 2(ASTM D 1238065T, condition F) and a high load melt index of about 3 to about 5 (ASTM D 1238-65T, condition F).
Description
~ t~ 3 PIPE EXTRUSIO~ POLYMERIC BLEND
This invention relates to the extrusion of plastic pipe. In one of its aspects this invention relates to polymers suitable for use in pipe extru-sion. In another of its aspects this invention relates to polymeric blends useful in pipe extrusion.
Polymers and polymeric blends used for pipe extrusion should, ideally, combine good flow capabilities and good performance capabilities in producing smooth extrudate. It has now been found that certain ethylene-hexene copolymers can be blended wi.h other ethylene copolymers and process aids to produce polymeric blends having desirable characteristics for pipe extrusion using either conventional extrusion or dynamic extrusion apparatus.
It is an object of this invention to provide polymeric blends useful in the extrusion of plastic pipe.
Other aspects, objects and the various advantages of this invention will become apparent upon reading this specification and the appended claims.
A polymeric blend composition suitable for use in dynamic and conventional extrusion apparatus is provided. The composition comprises from about 80 to about 15 weight percent of copolymer A, an ethylene-hexene copoly-mer of about 0.936 to about 0.940 density and a melt index of about 0.30 to about 0.45 (ASTM D 1238-65T, condition E); and about 10 to about 75 weight percent of copolymer B, a copolymer chosen from either ethylene butene copoly-mer of about 0.940 to about 0.942 density and high load melt index (HLMI) of about O to about 2 (ASTM D 1238-65T, condition F) or ethylene-hexene copolymer of about 0.942 to about 0.945 density and an HLMI of about 3 to about 5 (ASTM D 1238-65T, condition F); and about 5 to about 15 weight percent of a concentrate of copolymer A containing sufficient carbon black to produce a constant concentrate density in the range of about 1.0 to about 1.1.
In a preferred embodiment of the inYention the polymeric blend will contain, in addition to the components listed above~ an antioxidant in an amount equal to up to about 0.5 percent by weight of the polymer and a slip agent in an amount up to about 1.0 percent weight of the polymers.
Conventional extrusion of melted polymer through a screw extruder is well-known in the art. In conventional extrusion of plastic pipe, the extrudate may be forced through a die with no cooling or through a die having some cool-ing, but the cooling is only of such sufficiency that the extrudate must be sized and further cooled outside the die. In such extrusion, the extruded pipe requires support as it emerges from the die in a softened condition. In a dynamic extruder the extrusion apparatus is equipped with a die which has cooling channels so that the pipe emerges from the die in a froæen or hardened condition. The die completes the sizing of the pipe so that no external sizing operation is necessary. The polymer compositions of the present invention are useful in both types of extrusion.
The copolymers used both as copolymer A, the ethylene-hexene copoly-mer having melt index in the range measured by (ASTM D 1238-65T, condition E), and the copolymer chosen from ethylene butene copolymer and ethylene-hexene copolymer having high load melt index measured by tASTM D 1238-65T, condition F) are standard olefin copolymers which are well-known in the art. These copolymers can be prepared by methods such as those set out in U.S. 2,825,721.
The concentrate of copolymer A containing sufficient carbon black to produce a concentrate having a density in the range of about 1.0 to about 1.1 can also be prepared by well-known methods. The concentrate is made by blending the appropriate copolymer with a sufficient amount of carbon black to produce the desired density range with plasticizing, extrusion, and pellet-ing of a concentrate of the desired density.
To produce the blends useful in the process of this invention, appropriate amounts of the various components are dry blended and fed into extruder equipment either for dynamic extrusion or conventional screw extru-63C~
sion. The blend is plasticized and extruded by conventional means as taught by U.S. 3,239,881 and U.S. 3,309,436 for dynamic extrusion and by conventional extrusion as well-known in the art. Antioxidant and processing aids such as slip agents, can be added to the blend before extrusion as desired.
In the process of this invention and the compositions useful in the process, any of the well-known antioxidants useful with olefin polymers can be used. It has been found that 4,4-thiobis-(6-t-butyl-n-cresol) is particularly useful with the combination of components herein described.
Similarly, whereas slip agents normally found useful in the process-ing of extruded pipe are useful in the compositions herein described, a process-ing aid comprising two parts of Carbowax and one part glycerine has been found particularly suitable. Carbowax is polyethylene glycol sold by Union Carbide Company. The following examples are offered to describe the processing of the compositions described above into finished pipe using either dynamic extrusion or conventional screw extrusion.
Example I
A blend useful for pipe extrusion in a screw extruder was made containing 15 weight percent of an ethylene butene copolymer, density of O.940 to 0.942 and an ULMI of 1 to 2; 74.6 weight percent of an ethylene-hexene copolymer, density 0.936 to 0.940, and an MI of 0.30 to 0.45; 10 weight percent of a concentrate of the ethylene-hexene copolymer containing 25 weight percent carbon black; 0.1 weight percent of an antioxidant 4,4-thiobis-(6-t-butyl-n-cresol); and 0.3 weight percent of liquid ingredient containing five parts Carbowax sold by Union Carbide Company and two parts glycerine. The blend was fed to a 2 1~2 inch NRM extruder with a 4 inch pipe die attached.
The die had channels in both the mandrel and the die ring for circulation of cooling water for partially cooling the extrudate. Sufficient cooling was supplied to cause the extrudate to emerge f~om the die in a softened condition.
The softened extrudate was drawn down into a 3 inch sizing sleeve positioned at the entry to a cooling water tank to produce 3 inch pipe.
~z~
Example II
A blend was made containing 20 weight percent of an ethylene-hexene copolymer, density 0.942 to 0.`945 and an HLMI of 3 to 5; 69.8 weight percent of an ethylene-hexene copolymer, density 0.936 to 0.940, an MI of 0.30 to 0.45; and 10 weight percent of a concentrate of 0.936 to 0.940 hexene co-polymer containing 25 weight percent carbon black; 0.1 weight percent of the antioxidant 4,4-thiobis-(6-t-butyl-n-cresol); and 0.1 weight percent of liquid ingredient containing five parts Carbowax and two parts glycerine. The blend was fed to a 2 1/2 inch NRM extruder with a 1 1/4 inch pipe die attached.
The die had cooling channels in both the mandrel and die ring for partially cooling the extrudate. Sufficient cooling was supplied to cause the extrudate to emerge in a softened condition. The softened extrudate was drawn down into a 1 inch sizing sleeve attached in the entry of a cooling water tank to pro-duce 1 inch pipe.
Example III
Using the same blend, extruder, and pipe die as described in Example I, the die was operated as a dynamic extrusion die cooling the extru-date to the point that it emerged from the die in a frozen or hardened condi-tion and required no external sizing to produce 4 inch pipe.
This invention relates to the extrusion of plastic pipe. In one of its aspects this invention relates to polymers suitable for use in pipe extru-sion. In another of its aspects this invention relates to polymeric blends useful in pipe extrusion.
Polymers and polymeric blends used for pipe extrusion should, ideally, combine good flow capabilities and good performance capabilities in producing smooth extrudate. It has now been found that certain ethylene-hexene copolymers can be blended wi.h other ethylene copolymers and process aids to produce polymeric blends having desirable characteristics for pipe extrusion using either conventional extrusion or dynamic extrusion apparatus.
It is an object of this invention to provide polymeric blends useful in the extrusion of plastic pipe.
Other aspects, objects and the various advantages of this invention will become apparent upon reading this specification and the appended claims.
A polymeric blend composition suitable for use in dynamic and conventional extrusion apparatus is provided. The composition comprises from about 80 to about 15 weight percent of copolymer A, an ethylene-hexene copoly-mer of about 0.936 to about 0.940 density and a melt index of about 0.30 to about 0.45 (ASTM D 1238-65T, condition E); and about 10 to about 75 weight percent of copolymer B, a copolymer chosen from either ethylene butene copoly-mer of about 0.940 to about 0.942 density and high load melt index (HLMI) of about O to about 2 (ASTM D 1238-65T, condition F) or ethylene-hexene copolymer of about 0.942 to about 0.945 density and an HLMI of about 3 to about 5 (ASTM D 1238-65T, condition F); and about 5 to about 15 weight percent of a concentrate of copolymer A containing sufficient carbon black to produce a constant concentrate density in the range of about 1.0 to about 1.1.
In a preferred embodiment of the inYention the polymeric blend will contain, in addition to the components listed above~ an antioxidant in an amount equal to up to about 0.5 percent by weight of the polymer and a slip agent in an amount up to about 1.0 percent weight of the polymers.
Conventional extrusion of melted polymer through a screw extruder is well-known in the art. In conventional extrusion of plastic pipe, the extrudate may be forced through a die with no cooling or through a die having some cool-ing, but the cooling is only of such sufficiency that the extrudate must be sized and further cooled outside the die. In such extrusion, the extruded pipe requires support as it emerges from the die in a softened condition. In a dynamic extruder the extrusion apparatus is equipped with a die which has cooling channels so that the pipe emerges from the die in a froæen or hardened condition. The die completes the sizing of the pipe so that no external sizing operation is necessary. The polymer compositions of the present invention are useful in both types of extrusion.
The copolymers used both as copolymer A, the ethylene-hexene copoly-mer having melt index in the range measured by (ASTM D 1238-65T, condition E), and the copolymer chosen from ethylene butene copolymer and ethylene-hexene copolymer having high load melt index measured by tASTM D 1238-65T, condition F) are standard olefin copolymers which are well-known in the art. These copolymers can be prepared by methods such as those set out in U.S. 2,825,721.
The concentrate of copolymer A containing sufficient carbon black to produce a concentrate having a density in the range of about 1.0 to about 1.1 can also be prepared by well-known methods. The concentrate is made by blending the appropriate copolymer with a sufficient amount of carbon black to produce the desired density range with plasticizing, extrusion, and pellet-ing of a concentrate of the desired density.
To produce the blends useful in the process of this invention, appropriate amounts of the various components are dry blended and fed into extruder equipment either for dynamic extrusion or conventional screw extru-63C~
sion. The blend is plasticized and extruded by conventional means as taught by U.S. 3,239,881 and U.S. 3,309,436 for dynamic extrusion and by conventional extrusion as well-known in the art. Antioxidant and processing aids such as slip agents, can be added to the blend before extrusion as desired.
In the process of this invention and the compositions useful in the process, any of the well-known antioxidants useful with olefin polymers can be used. It has been found that 4,4-thiobis-(6-t-butyl-n-cresol) is particularly useful with the combination of components herein described.
Similarly, whereas slip agents normally found useful in the process-ing of extruded pipe are useful in the compositions herein described, a process-ing aid comprising two parts of Carbowax and one part glycerine has been found particularly suitable. Carbowax is polyethylene glycol sold by Union Carbide Company. The following examples are offered to describe the processing of the compositions described above into finished pipe using either dynamic extrusion or conventional screw extrusion.
Example I
A blend useful for pipe extrusion in a screw extruder was made containing 15 weight percent of an ethylene butene copolymer, density of O.940 to 0.942 and an ULMI of 1 to 2; 74.6 weight percent of an ethylene-hexene copolymer, density 0.936 to 0.940, and an MI of 0.30 to 0.45; 10 weight percent of a concentrate of the ethylene-hexene copolymer containing 25 weight percent carbon black; 0.1 weight percent of an antioxidant 4,4-thiobis-(6-t-butyl-n-cresol); and 0.3 weight percent of liquid ingredient containing five parts Carbowax sold by Union Carbide Company and two parts glycerine. The blend was fed to a 2 1~2 inch NRM extruder with a 4 inch pipe die attached.
The die had channels in both the mandrel and the die ring for circulation of cooling water for partially cooling the extrudate. Sufficient cooling was supplied to cause the extrudate to emerge f~om the die in a softened condition.
The softened extrudate was drawn down into a 3 inch sizing sleeve positioned at the entry to a cooling water tank to produce 3 inch pipe.
~z~
Example II
A blend was made containing 20 weight percent of an ethylene-hexene copolymer, density 0.942 to 0.`945 and an HLMI of 3 to 5; 69.8 weight percent of an ethylene-hexene copolymer, density 0.936 to 0.940, an MI of 0.30 to 0.45; and 10 weight percent of a concentrate of 0.936 to 0.940 hexene co-polymer containing 25 weight percent carbon black; 0.1 weight percent of the antioxidant 4,4-thiobis-(6-t-butyl-n-cresol); and 0.1 weight percent of liquid ingredient containing five parts Carbowax and two parts glycerine. The blend was fed to a 2 1/2 inch NRM extruder with a 1 1/4 inch pipe die attached.
The die had cooling channels in both the mandrel and die ring for partially cooling the extrudate. Sufficient cooling was supplied to cause the extrudate to emerge in a softened condition. The softened extrudate was drawn down into a 1 inch sizing sleeve attached in the entry of a cooling water tank to pro-duce 1 inch pipe.
Example III
Using the same blend, extruder, and pipe die as described in Example I, the die was operated as a dynamic extrusion die cooling the extru-date to the point that it emerged from the die in a frozen or hardened condi-tion and required no external sizing to produce 4 inch pipe.
Claims
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A polymeric blend composition suitable for both dynamic and conventional screw extrusion of plastic pipe said composition comprising from about 80 to about 15 weight percent of copolymer A, an ethylene-hexene copolymer of about 0.936 to about 0.940 density and a melt index of about 0.30 to about 0.45 (ASTM D 1238-65T, condition E); about 10 to about 75 weight percent of copolymer B, a copolymer chosen from a group consisting of ethylene butene copolymer of about 0.940 to about 0.942 density and HMLI of about O to about 2 (ASTM D 1238-65T, condition F), and ethylene-hexene copolymer of about 0.942 to about 0.945 density and HLMI
of about 3 to about 5 (ASTM D 1238-65T, condition F); and about 5 to about 15 weight percent of a concentrate of copolymer A containing sufficient carbon black to produce a concentrate of density in the range of about 1.0 to about 1.1.
2. A polymer blend composition of claim 1 wherein copolymer B is ethylene butene copolymer.
3. A polymer blend composition of claim 1 wherein copolymer B
is ethylene-hexene copolymer.
4. A polymer blend of claim 1 also containing an antioxidant.
5. A polymer blend of claim 4 also containing a slip agent.
6. A polymer blend of claim 4 wherein said antioxidant is 4,4-thiobis-(6-t-butyl-n-cresol).
7. A polymer blend of claim 5 wherein said slip agent is comprised of two parts polyethylene glycol and one part glycerine.
8. A method for producing plastic pipe comprising extruding a polymer blend composition of claim 1 using an apparatus chosen from the group of dynamic extruders and conventional screw extruders.
9. A plastic pipe produced from a polymer blend composition of
claim 1.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US84151377A | 1977-10-12 | 1977-10-12 | |
| US841,513 | 1977-10-12 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1120630A true CA1120630A (en) | 1982-03-23 |
Family
ID=25285077
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000312081A Expired CA1120630A (en) | 1977-10-12 | 1978-09-26 | Pipe extrusion polymeric blend |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1120630A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20100016481A1 (en) * | 2006-10-02 | 2010-01-21 | Borealis Technology Oy | Polyolefin composition with increased resistance to cio2-containing water |
-
1978
- 1978-09-26 CA CA000312081A patent/CA1120630A/en not_active Expired
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20100016481A1 (en) * | 2006-10-02 | 2010-01-21 | Borealis Technology Oy | Polyolefin composition with increased resistance to cio2-containing water |
| US20140109975A1 (en) * | 2006-10-02 | 2014-04-24 | Borealis Technology Oy | Polyolefin composition with increased resistance to cio2-containing water |
| US9376548B2 (en) * | 2006-10-02 | 2016-06-28 | Borealis Technology Oy | Polyolefin composition with increased resistance to ClO2-containing water |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry | ||
| MKEX | Expiry |
Effective date: 19990323 |