Rotational molding and compositions therefor

• US 3,876,613 A
• Filed: 12/27/1972
• Issued: 04/08/1975
• Est. Priority Date: 12/27/1972
• Status: Expired due to Term

• Current Assignee: Donald G. Needham, George R. Hill, Robert J. Martinovich
• Original Assignee: Donald G. Needham, George R. Hill, Robert J. Martinovich
• Inventors: Needham, Donald G., Hill, George R., Martinovich, Robert J.
• Primary Examiner(s): Hoke, V. P.
• Application Number:
  US05/318,968
• Time in Patent Office: 832 Days
• Field of Search: 260/94.9GA,45.85S
• US Class Current: 524/307
• CPC Class Codes: B29C 41/003 characterised by the choice of material
• CPC Class Codes: B29C 41/04 Rotational or centrifugal casting, i.e. coating the inside of a mould by rotating the mould
• CPC Class Codes: B29K 2023/06 PE, i.e. polyethylene
• CPC Class Codes: B29K 2105/24 crosslinked or vulcanised
• CPC Class Codes: C08K 5/14 Peroxides
• CPC Class Codes: C08K 5/37 Thiols
• CPC Class Codes: C08K 5/372 Sulfides , e.g. R-(S)x-R'
• CPC Class Codes: C08L 23/04 Homopolymers or copolymers of ethene

Abstract

Polymers of ethylene are rotationally molded and crosslinked to produce molded articles having high strength utilizing compositions including an ester of thiodipropionic acid in addition to the crosslinking agent.

Claims

1. A COMPOSITION OF MATTER FORMED BY INCORPORATING INTO A SOLID POLYMER SELECTED FROM THE GROUP CONSISTING OF ETHYLENE HOMOPOLYMERS, COPOLYMERS OF ETHYLENE AND AT LEAST ONE ACYCLIC MONO-1 OLEFIN HYDROCARBON HAVING 3 TO 8 CARBON ATOMS PER MOLECULE, AND MIXTURES THEREOF, HAVING A MELT INDEX OF AT LEAST ABOUT 10, A DENSITY IN THE RANGE OF 0.920 - 0.970, AND A MOLECULAR WEIGHT DISTRIBUTION NOT GREATER THAN ABOUT 7, A. A CROSSLINKING AMOUNT OF AN ACETYLENIC DIPEROXY COMPOUND SELECTED FROM THE GROUP CONSISTING OF HEXYNES HAVING THE FORMULA

2. The composition of claim 1 wherein R.sub.1 and R.sub.2 are the same and

3. The composition of claim 2 wherein R.sub.1 and R.sub.2 are selected from the group consisting of lauryl, stearyl, myristyl, oleyl and ricinoleyl.

4. The composition of claim 1 wherein the ester of thiodipropionic acid is dilaurylthiodipropionate, the amount of the ester is 0.03-0.06 weight percent, the acetylenic diperoxide compound is 2,5-dimethyl-2,5-di(t-butylperoxy)hexyne-3 and the amount of the

5. A composition according to claim 4 wherein said solid polymer is an

6. A composition according to claim 4 wherein said solid polymer is a copolymer of ethylene and 1-butene having a density in the range of

7. A method for producing hollow articles which comprises rotationally molding a composition of matter formed by incorporating into a solid polymer selected from the group consisting of ethylene homopolymers, copolymers of ethylene and at least one acyclic mono-1 olefin hydrocarbon having 3 to 8 carbon atoms per molecule, and mixtures thereof, having a melt index of at least about 10, a density in the range of 0.920-0.970, and a molecular weight distribution not greater than about 7, a. a crosslinking amount of an acetylenic diperoxy compound selected from the group consisting of hexynes having the formula

8. The method according to claim 7 wherein R.sub.1 and R.sub.2 are the same

9. The method according to claim 8 wherein R.sub.1 and R.sub.2 are selected from the group consisting of lauryl, stearyl, myristyl, oleyl and

10. The method according to claim 7 wherein the ester of thiodipropionic acid is dilaurylthiodipropionate, the amount of the ester is 0.03- 0.06 weight percent, the acetylenic diperoxide compound is 2,5-dimethyl-2,5-di(t-butylperoxy)hexyne-3 and the amount of the

11. The method according to claim 10 wherein said solid polymer is an

12. The method according to claim 10 wherein said solid polymer is a copolymer of ethylene and 1-butene having a density in the range of 0.940-0.970.