CA1131196A - Peroxide blends - Google Patents
Peroxide blendsInfo
- Publication number
- CA1131196A CA1131196A CA337,848A CA337848A CA1131196A CA 1131196 A CA1131196 A CA 1131196A CA 337848 A CA337848 A CA 337848A CA 1131196 A CA1131196 A CA 1131196A
- Authority
- CA
- Canada
- Prior art keywords
- peroxide
- blend
- meta
- alpha
- benzene
- 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.)
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- Compositions Of Macromolecular Compounds (AREA)
Abstract
PEROXIDE BLENDS
Abstract of the Disclosure Disclosed is a novel blend of peroxides that is liquid at room temperature. The blend consists essentially of bis(alpha-?-butylperoxyisopropyl) benzene and isopropylcumyl ?-butyl peroxide. The blend is useful in crosslinking polymers such as polyethylene.
Abstract of the Disclosure Disclosed is a novel blend of peroxides that is liquid at room temperature. The blend consists essentially of bis(alpha-?-butylperoxyisopropyl) benzene and isopropylcumyl ?-butyl peroxide. The blend is useful in crosslinking polymers such as polyethylene.
Description
This invention relates to peroxide blends for use in the crosslinking of polymers such as polyethylene, EPDM and copolymers of ethylene and vinyl acetate.
The use of peroxides for crosslinking polymers is facilitated if the crosslinking agents are in the liquid rather than the solid state. Known crosslinking agents are either solid crystalline materials having a melting point above room temperature or have been mixed with non-active materials that serve to lower the melting point of the agent to below room temperature. The inclusion of non-active materials reduces the crosslinking efficiency and it is therefore desirable to provide liquid crosslinking agents that are composed entirely of peroxides having crosslinking activity.
According to the invention there is provided a cross-linking agent that comprises a solid peroxide crosslinking agent, namely bis(alpha-t-butyl peroxyisopropyl)benzene, characterized in that to the said agent is added isopropyl-cumyl-t-butyl peroxide to provide a blend containing 75% to 90% of the latter, thereby rendering the said agent liquid at an ambient temperature of 23C.
In this specification and in the claims, all parts and percentages are by weight unless otherwise specified.
The peroxide blend of this invention consists essenti-ally of from about 25% to about 10% bis(alpha-t-butylperoxy-isopropyl) benzene and from about 75% to about 90% iso-propylcumyl t-butyl peroxide.
Preferably, the peroxide blend consists essentially of from about 25% to about 20% bis(alpha-t-butylperoxyiso-propyl) benzene and from about 75% to about 80% isopropyl-cumyl-t-butyl peroxide.
Bis-(alpha-t-butylperoxyisopropyl) benzene is well known in the art as are the methods for the preparation thereof.
This bisperoxide has the formula (I) below.
(I) CH3 - C - O - O - C ~ C - O - O - C - CH3 Specific examples of the bisperoxide are the meta and para isomers thereof. Mixtures of the meta and para isomers are commercially available and are preferred for use in this in-vention. The meta and para isomers are solid at room tem-perature as are all mixtures thereof. The meta isomer melts at about 52C., the para isomer melts at about 79C., and the eutectic mixture (80~ meta isomer) melts at about 45C.
Bis(alpha-t-butylperoxyisopropyl) benzene is a cross-linking agent for certain polymers such as polyethylene.
- See U.S. patent Re. 25,941.
Isopropylcumyl t-butyl peroxide is liquid at room tem-perature and has the formula (II) below.
(II) HC ~ C - O - O - C - CH3 ; Specific examples thereof are meta-isopropylcumyl t-butyl peroxide and para-isopropylcumyl t-butyl peroxide. Mix-tures of the meta and para isomer, a mixture of about 2 parts meta isomer and about 1 part para isomer for example, can be used in carrying out this invention. All meta and para mixtures are liquid at room temperature.
Example 1 The apparatus used in this example consisted of a 4-necked round-bottom flask equipped with a thermometer, a mecha-ical stirrer, and an ice water-cooled Friedrich con-denser with a Barrett moisture trap. Reduced pressure was read on a U-tube manometer and controlled with a twenty-turn needle valve through appropriate hose connections.
To the flask were charged 713 grams (4.0 moles) of a mixture of the meta and para isomers of ~3~196 isopropyl-alpha,-alpha-dimethylbenzyl alcohol (ratio of meta to para is about 2 to 1), 440 grams of 90% aqueous solution of t-butyl hydroperoxide (4.4 moles of hydroperoxide), and 769 grams of heptane. The resulting mixture was stirred at 30-35C. while refluxing at reduced pressure until essen-tially all water present in the hydroperoxide solution had been collected in the Barrett trap. The trap was then drained of water and p-toluenesulfonic acid monohydrate (7.6 grams, 0.04 mole) dissolved in 7 ml. water was added to the mixture in the flask. Stirring at reflux ~30-35C.) under reduced pressure was continued until no more water was being collected in the Barrett trap (about 9 hours).
At that point the reaction mixture became darker in appearance.
250 ml. of a 5% aqueous solution of NaOH was added to the reaction mixture and the thus diluted reaction mixture was transferred to a separatory funnel. The aqueous phase was removed from the funnel and the organic phase was washed four more times with 5% aqueous solution of NaOH followed by three washes of 500 ml. of distilled water each. The organic phase was dried over MgSO4, filtered, and stripped on a rotary evaporator; first at 50C. with aspirator vacuum to remove heptane and finally at 65-70C. and 0.1 Torr. The product consisted essentially of a mixture of the meta and para isomers of isopropyl cumyl t-butyl peroxide. The prod-uct weighed 940.8 grams and contained 87.2% peroxide as determined by the iodine liberation method. This represen-ted a yield of 82% based on the alcohol used. The product was a clear light yellow liquid at room temperature.
Example 2 A peroxide blend that is liquid at room temperature was prepared by dissolving 25 parts bis(alpha-t-butylperoxyiso-propyl) benzene (essentially a 2 to 1 mixture of the meta and para isomers) in 75 parts of the product of Example 1.
The isopropylcumyl t-butyl peroxide was a mixture of about
The use of peroxides for crosslinking polymers is facilitated if the crosslinking agents are in the liquid rather than the solid state. Known crosslinking agents are either solid crystalline materials having a melting point above room temperature or have been mixed with non-active materials that serve to lower the melting point of the agent to below room temperature. The inclusion of non-active materials reduces the crosslinking efficiency and it is therefore desirable to provide liquid crosslinking agents that are composed entirely of peroxides having crosslinking activity.
According to the invention there is provided a cross-linking agent that comprises a solid peroxide crosslinking agent, namely bis(alpha-t-butyl peroxyisopropyl)benzene, characterized in that to the said agent is added isopropyl-cumyl-t-butyl peroxide to provide a blend containing 75% to 90% of the latter, thereby rendering the said agent liquid at an ambient temperature of 23C.
In this specification and in the claims, all parts and percentages are by weight unless otherwise specified.
The peroxide blend of this invention consists essenti-ally of from about 25% to about 10% bis(alpha-t-butylperoxy-isopropyl) benzene and from about 75% to about 90% iso-propylcumyl t-butyl peroxide.
Preferably, the peroxide blend consists essentially of from about 25% to about 20% bis(alpha-t-butylperoxyiso-propyl) benzene and from about 75% to about 80% isopropyl-cumyl-t-butyl peroxide.
Bis-(alpha-t-butylperoxyisopropyl) benzene is well known in the art as are the methods for the preparation thereof.
This bisperoxide has the formula (I) below.
(I) CH3 - C - O - O - C ~ C - O - O - C - CH3 Specific examples of the bisperoxide are the meta and para isomers thereof. Mixtures of the meta and para isomers are commercially available and are preferred for use in this in-vention. The meta and para isomers are solid at room tem-perature as are all mixtures thereof. The meta isomer melts at about 52C., the para isomer melts at about 79C., and the eutectic mixture (80~ meta isomer) melts at about 45C.
Bis(alpha-t-butylperoxyisopropyl) benzene is a cross-linking agent for certain polymers such as polyethylene.
- See U.S. patent Re. 25,941.
Isopropylcumyl t-butyl peroxide is liquid at room tem-perature and has the formula (II) below.
(II) HC ~ C - O - O - C - CH3 ; Specific examples thereof are meta-isopropylcumyl t-butyl peroxide and para-isopropylcumyl t-butyl peroxide. Mix-tures of the meta and para isomer, a mixture of about 2 parts meta isomer and about 1 part para isomer for example, can be used in carrying out this invention. All meta and para mixtures are liquid at room temperature.
Example 1 The apparatus used in this example consisted of a 4-necked round-bottom flask equipped with a thermometer, a mecha-ical stirrer, and an ice water-cooled Friedrich con-denser with a Barrett moisture trap. Reduced pressure was read on a U-tube manometer and controlled with a twenty-turn needle valve through appropriate hose connections.
To the flask were charged 713 grams (4.0 moles) of a mixture of the meta and para isomers of ~3~196 isopropyl-alpha,-alpha-dimethylbenzyl alcohol (ratio of meta to para is about 2 to 1), 440 grams of 90% aqueous solution of t-butyl hydroperoxide (4.4 moles of hydroperoxide), and 769 grams of heptane. The resulting mixture was stirred at 30-35C. while refluxing at reduced pressure until essen-tially all water present in the hydroperoxide solution had been collected in the Barrett trap. The trap was then drained of water and p-toluenesulfonic acid monohydrate (7.6 grams, 0.04 mole) dissolved in 7 ml. water was added to the mixture in the flask. Stirring at reflux ~30-35C.) under reduced pressure was continued until no more water was being collected in the Barrett trap (about 9 hours).
At that point the reaction mixture became darker in appearance.
250 ml. of a 5% aqueous solution of NaOH was added to the reaction mixture and the thus diluted reaction mixture was transferred to a separatory funnel. The aqueous phase was removed from the funnel and the organic phase was washed four more times with 5% aqueous solution of NaOH followed by three washes of 500 ml. of distilled water each. The organic phase was dried over MgSO4, filtered, and stripped on a rotary evaporator; first at 50C. with aspirator vacuum to remove heptane and finally at 65-70C. and 0.1 Torr. The product consisted essentially of a mixture of the meta and para isomers of isopropyl cumyl t-butyl peroxide. The prod-uct weighed 940.8 grams and contained 87.2% peroxide as determined by the iodine liberation method. This represen-ted a yield of 82% based on the alcohol used. The product was a clear light yellow liquid at room temperature.
Example 2 A peroxide blend that is liquid at room temperature was prepared by dissolving 25 parts bis(alpha-t-butylperoxyiso-propyl) benzene (essentially a 2 to 1 mixture of the meta and para isomers) in 75 parts of the product of Example 1.
The isopropylcumyl t-butyl peroxide was a mixture of about
2 parts meta isomer and 1 part para isomer.
Examples 3-4 The following polyethylene compositions were prepared and cured at 360F.
Composition 3 4 Low density polyethylene - 100 100 parts Antioxidant (AgeRite 0.5 0.5 Resin D) - parts bis(alpha-t-Butylperoxy- 1.2 isopropyl)benzene - parts Example 2 peroxide blend - - 2.03 parts Cure time (min.) 20 20 Physical properties of the cured compositions are set forth below in Table I.
TABLE I
Cured Composition _ _ 100% Modulus (psi) 1095 1165 Tensile Strength (psi)27952500 Elongation, % 550 550 Shore A Hardness 96 96 Shore D Hardness 47 47 Heat Distortion % 10.6 11.3 (ASTM D2655) Bis(alpha-t-butylperoxyisopropyl) benzene is a solid at room temperature. One of the disadvantages of this peroxide is that it must be melted in order to be uniformly dispersed in polymers, such as polyethylene, prior to cure. This causes additional expense to the user and is a source of danger as there is always the possibility of overheating, particularly by unskilled personnel, which can result in rapid decomposi-tion of the peroxide and may even result in explosion.Blending of the solid peroxide with polymers, such as poly-ethylene, is not satisfactory in that it is difficult, if not impossible, to obtain uniform dispersion of the peroxide throughout the polymer. It is essential that the peroxide be uniformly dispersed in order to provide uniform curing or crosslinking of the polymer.
. .
113~96 The peroxide blend of this invention, being liquid at room temperature, is easily and readily admixed with such polymers as polyethylene to provide essentially uniform blends of polymer and peroxide without undesirable effects. The polymer-peroxide compositions, after curing, have good physical properties.
Examples 3-4 The following polyethylene compositions were prepared and cured at 360F.
Composition 3 4 Low density polyethylene - 100 100 parts Antioxidant (AgeRite 0.5 0.5 Resin D) - parts bis(alpha-t-Butylperoxy- 1.2 isopropyl)benzene - parts Example 2 peroxide blend - - 2.03 parts Cure time (min.) 20 20 Physical properties of the cured compositions are set forth below in Table I.
TABLE I
Cured Composition _ _ 100% Modulus (psi) 1095 1165 Tensile Strength (psi)27952500 Elongation, % 550 550 Shore A Hardness 96 96 Shore D Hardness 47 47 Heat Distortion % 10.6 11.3 (ASTM D2655) Bis(alpha-t-butylperoxyisopropyl) benzene is a solid at room temperature. One of the disadvantages of this peroxide is that it must be melted in order to be uniformly dispersed in polymers, such as polyethylene, prior to cure. This causes additional expense to the user and is a source of danger as there is always the possibility of overheating, particularly by unskilled personnel, which can result in rapid decomposi-tion of the peroxide and may even result in explosion.Blending of the solid peroxide with polymers, such as poly-ethylene, is not satisfactory in that it is difficult, if not impossible, to obtain uniform dispersion of the peroxide throughout the polymer. It is essential that the peroxide be uniformly dispersed in order to provide uniform curing or crosslinking of the polymer.
. .
113~96 The peroxide blend of this invention, being liquid at room temperature, is easily and readily admixed with such polymers as polyethylene to provide essentially uniform blends of polymer and peroxide without undesirable effects. The polymer-peroxide compositions, after curing, have good physical properties.
Claims (4)
1. A peroxide blend that is liquid at room temperature consisting essentially of (1) from about 25% to about 10%
bis(alpha-?-butylperoxyisopropyl) benzene and (2) from about 75% to about 90% isopropylcumyl ?-butyl peroxide.
bis(alpha-?-butylperoxyisopropyl) benzene and (2) from about 75% to about 90% isopropylcumyl ?-butyl peroxide.
2. A peroxide blend that is liquid at room temperature consisting essentially of (1) from about 25% to about 20%
bis(alpha-?-butylperoxyisopropyl) benzene and (2) from about 75% to about 80% isopropylcumyl ?-butyl peroxide.
bis(alpha-?-butylperoxyisopropyl) benzene and (2) from about 75% to about 80% isopropylcumyl ?-butyl peroxide.
3. The peroxide blend of claim 2 wherein peroxide (1) is a mixture of the meta and para isomers and peroxide (2) is a mixture of the meta and para isomers.
4. In the method of crosslinking polymers using a peroxide curing agent the improvement wherein there is employed the peroxide blend of claim 1, 2, or 3.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA337,848A CA1131196A (en) | 1979-10-17 | 1979-10-17 | Peroxide blends |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA337,848A CA1131196A (en) | 1979-10-17 | 1979-10-17 | Peroxide blends |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1131196A true CA1131196A (en) | 1982-09-07 |
Family
ID=4115370
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA337,848A Expired CA1131196A (en) | 1979-10-17 | 1979-10-17 | Peroxide blends |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1131196A (en) |
-
1979
- 1979-10-17 CA CA337,848A patent/CA1131196A/en not_active Expired
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| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |