EP0733456A2
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System for optimizing cure and assuring quality of reversion susceptible rubber articles
Assignee: Pirelli Tyre SpA
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Filing: 1996-03-19
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Granted: —
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Expires: 2016-03-19
Abstract
Abstract A database of reversion cure constants is provided by measuring a physical property of a rubber formulation at two different temperatures as a function of time, calculating a set of cure constants for the rubber formulation which account for reversion, and storing the constants for later use either to optimize cure for a given process or of a given compound, or to assure quality of a raw compound. The invention also provides a curing press for optimizing cure including a mold, a heater, a temperature transducer, a computer and the database.
Inventors
- 👤 Giovanni Rimondi
- 👤 William James Toth
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-30 21:49
CPC Classifications
B; B29; B29C; B29C35/00; B29C35/02; B29C35/0288; B29C37/00; B29C2037/90; B29C2037/903; B29D; B29D30/00; B29D30/06; B29D30/0601; B29D30/0662; B29D2030/0675; B29K; B29K2021/00; B29L; B29L2030/00; G; G01; G01N; G01N2203/00; G01N2203/0058; G01N2203/0092; G01N33/00; G01N33/44
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
106 words
A method for creating a database of cure constants, which account for reversion, for later use to optimize cure of a rubber compound, comprising the steps of: providing a plurality of rubber samples, each sample having a particular rubber formulation; for at least two different temperatures, measuring a physical property which can be related to cure state of a sample of each different formulation as a function of time; calculating a set of cure constants for the rubber formulation which account for reversion from the physical property versus time profiles; and storing the set of cure constants on the database together with the corresponding rubber formulation.
Claim 2
Dependent Claim
50 words
The method of claim 1 wherein the calculating step comprises calculating a set of isothermal cure constants at each temperature for each sample from its physical property-time profile, expressing the isothermal constants with a formula which describes their temperature dependence, and calculating the non-isothermal cure constants for each rubber formulation.
Claim 3
Dependent Claim
15 words
The method of claim 2 wherein the measuring step comprises measuring torque with a rheometer.
Claim 4
Dependent Claim
43 words
The method of claim 3 including the step of retrieving the non-isothermal cure constants from the database for a selected rubber formulation and combining them with a temperature-time profile of a curing process to predict state of cure of the selected rubber formulation.
Claim 5
Independent Claim
79 words
A method for optimizing cure of a rubber compound, comprising the steps of: providing a database including non-isothermal cure constants for the rubber compound which account for reversion; providing a curing process for the rubber compound; determining a temperature-time profile of the rubber compound for the curing process; reducing the temperature-time profile and the non-isothermal cure constants with numerical analysis into a succession of isothermal cases; and determining whether the curing process will optimize cure for the rubber compound.
Claim 6
Dependent Claim
20 words
The method of claim 5 wherein the determining step comprises measuring the temperature-time profile during curing of the rubber compound.
Claim 7
Dependent Claim
53 words
The method of claim 6 wherein the non-isothermal cure constants are K o α and E α , K o β and E β , K o γ and E γ , Γ o e and E e , Γ o o and E o , and n o and E n .
Claim 8
Dependent Claim
35 words
The method of claim 7 wherein the curing process providing step comprises selecting a curing process, and including the step of changing the curing process when optimized cure is not achieved for the rubber compound.
Claim 9
Dependent Claim
23 words
The method of claim 8 including the step of changing a formulation of the rubber compound when an optimized cure is not achieved.
Claim 10
Independent Claim
124 words
A method for assuring the quality of manufactured rubber articles comprising the steps of: preparing a rubber sample according to a production formulation; measuring, at a given temperature and as a function of time, a physical property of the rubber sample which can be related to cure state of the article; applying a curing model which accounts for reversion to the isothermal physical property-time profile to generate a set of measured isothermal cure constants; retrieving a set of predicted cure constants for the production formulation at the given temperature from a database of predicted cure constants; and comparing the measured isothermal cure constants with the predicted cure constants to determine whether a rubber article produced with the production formulation will have an optimized cure.
Claim 11
Dependent Claim
27 words
The method of claim 10 wherein the measuring step comprises using a rheometer to take torque versus time measurements of the rubber sample at the given temperature.
Claim 12
Dependent Claim
32 words
The method of claim 11 wherein the applying step comprises calculating measured isothermal cure constants K α , K β , K γ , Γ e , Γ o and n .
Claim 13
Dependent Claim
31 words
The method of claim 12 wherein the retrieving step comprises retrieving predicted isothermal cure constants K α , K β , K γ Γ e , Γ o and n .
Claim 14
Dependent Claim
91 words
The method of claim 12 wherein the retrieving step comprises the steps of: retrieving predicted non-isothermal cure constants K o α and E α , K o β and E β , K o γ and E γ , Γ o e and E e , Γ o o and E o , and n o and E n ; and calculating predicted isothermal cure constants K α , K β , K γ , Γ e , Γ o and n from the predicted non-isothermal constants and the given temperature.
Claim 15
Dependent Claim
34 words
The method of claim 14 including the step of searching the database of predicted cure constants at the given temperature with the measured isothermal cure constants to determine a formulation of the rubber sample.
Claim 16
Dependent Claim
29 words
A method of claim 14 including the step of curing a portion of the rubber sample with a process determined to provide an optimized cure for the production formulation.
Claim 17
Dependent Claim
94 words
A curing press for manufacturing an article from a rubber formulation with an optimized cure, comprising: a mold having at least two segments; means for heating said mold; a transducer for generating a signal indicative of a temperature within said mold; and a computer for receiving and storing the temperature indicative signal as a function of time and for storing a set of non-isothermal cure constants for the rubber formulation, said computer for reducing the temperature-time profile and the cure constants to a succession of isothermal cases to determine whether the cure was optimized.
Claim 18
Dependent Claim
32 words
The curing press of claim 17 wherein the set of non-isothermal cure constants are calculated by measuring a sample of the rubber formulation with a rheometer for at least two different temperatures.
Claim 19
Dependent Claim
24 words
The curing press of claim 18 wherein said transducer is located within the mold in contact with a surface of the article being cured.
References Cited (Backward Citations)
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