US3956253A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Polyethylene molding compounds of high-wear resistance
Assignee: Hoechst AG
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Filing: 1975-09-05
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Granted: 1976-05-11
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Expires: 1995-09-05
Abstract
Abstract A polyethylene composition of high wear resistance and a method of preparing it which comprises a polyethylene prepared according to a low pressure polymerization process and which has a molecular weight above about 1,000,000, containing an organic peroxide cross-linking agent homogeneously dispersed in the polymer, which has been pre-compressed at a high pressure, plasticized at elevated temperature and pressure and cooled.
Inventors
- 👤 Gunther Braun
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 11:15
CPC Classifications
C; C08; C08K; C08K5/00; C08K5/04; C08K5/14; C08K3/00; C08K3/34; C08K3/36; C08L; C08L23/00; C08L23/02; C08L23/04; C08L23/06; C08L2312/00
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
99 words
A method for preparing a polyethylene composition having high wear resistance which comprises homogeneously mixing a peroxide cross-linking agent with a polyethylene powder having a viscosimetrically determined molecular weight of at least 1,000,000, said cross-linking agent being present in an amount of 0.2 to 0.6% by weight pre-compressing the mixture at pressure of at least 50 kp/cm 2 to obtain a pre-compressed polyethylene mixture, plasticizing the mixtue at a temperature of at least about 200°C at a pressure of at least 50 kp/cm 2 , and cooling the plasticized mixture to obtain the polyethylene composition of high wear resistance.
Claim 2
Independent Claim
99 words
A method for preparing a polyethylene composition having high wear resistance which comprises homogeneously mixing a peroxide cross-linking agent with a polyethylene powder having a viscosimetrically determined molecular weight of at least 1,000,000, said cross-linking agent being present in an amount of 0.2 to 0.6% by weight pre-compressing the mixture at pressure of at least 50 kp/cm 2 to obtain a pre-compressed polyethylene mixture, plasticizing the mixtue at a temperature of at least about 200°C at a pressure of at least 50 kp/cm 2 , and cooling the plasticized mixture to obtain the polyethylene composition of high wear resistance.
Claim 3
Dependent Claim
21 words
The method of claim 1 in which the mixing step is further characterized by the addition of an inert carrier material.
Claim 4
Dependent Claim
37 words
The method of claim 2 in which the inert carrier material is SiO 2 and which is present in an amount of 50 to 100 percent by weight, based upon the weight of the peroxide cross-linking agent.
Claim 5
Dependent Claim
22 words
The method of claim 1 in which the plasticized mixture is cooled under a pressure of at least 100 kp/cm 2 .
Claim 6
Dependent Claim
13 words
The method of claim 1 in which the peroxide is a peroxyphthalide compound.
Claim 7
Dependent Claim
11 words
The method of claim 1 in which the peroxide is 3-phenyl-3-(t-butyl)peroxyphthalide.
Claim 8
Dependent Claim
68 words
A polyethylene composition of high wear resistance comprising a polyethylene polymer having a viscosimetrically determined molecular weight of at least 1,000,000 containing 0.2 to 0.6% by weight of a peroxide cross-linking agent, and which has been precompressed in a pressure of at least 50 kp/cm 2 , plasticized at a temperature of at least about 200°C at a pressure of at least 50 kp/cm 2 , and cooled.
Claim 9
Dependent Claim
68 words
A polyethylene composition of high wear resistance comprising a polyethylene polymer having a viscosimetrically determined molecular weight of at least 1,000,000 containing 0.2 to 0.6% by weight of a peroxide cross-linking agent, and which has been precompressed in a pressure of at least 50 kp/cm 2 , plasticized at a temperature of at least about 200°C at a pressure of at least 50 kp/cm 2 , and cooled.
Claim 10
Dependent Claim
60 words
A polyethylene composition of high wear resistance comprising a polyethylene polymer having a viscosimetrically determined molecular weight of at least 1,000,000 containing a peroxide cross-linking agent, which has been precompressed at a pressure of at least 50 kp/cm 2 , plasticized at a temperature of at least about 200°C at a pressure of at least 50 kp/cm 2 and cooled.
Claim 11
Dependent Claim
60 words
A polyethylene composition of high wear resistance comprising a polyethylene polymer having a viscosimetrically determined molecular weight of at least 1,000,000 containing a peroxide cross-linking agent, which has been precompressed at a pressure of at least 50 kp/cm 2 , plasticized at a temperature of at least about 200°C at a pressure of at least 50 kp/cm 2 and cooled.
Claim 12
Dependent Claim
22 words
The composition of claim 8 in which the peroxide is present in an amount of 0.2 to 0.6 per cent by weight.
Claim 13
Dependent Claim
15 words
The composition of claim 8 in which the peroxide cross-linking agent is a peroxyphthalide compound.
Claim 14
Dependent Claim
16 words
The composition of claim 8 is further characterized in that it contains an inert carrier material.
Claim 15
Dependent Claim
15 words
The composition of claim 11 in which the inert carrier material is SiO 2 .
Claim 16
Dependent Claim
33 words
The composition of claim 12 in which the SiO 2 is present in an amount of about 50 to 100 per cent by weight based on the weight of the peroxide cross-linking agent.
Claim 17
Dependent Claim
13 words
The composition of claim 8 in which the peroxide cross-linking agent is 3-phenyl-3-(t-butyl)peroxyphthalide.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-05-11 | 1979-11-10 | 1980-05-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-05-11 | 1983-11-10 | 1984-05-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-05-11 | 1987-11-10 | 1988-05-11 | $7700.00 | Window Closed / Lapsed |