JPS60178010A - Vulcanizing method - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (1) Industrial Application Field The present invention relates to a method of curing or vulcanizing an article by heating.

Although the present invention has particular application in curing tires, it can also be used in other rubber products such as hoses, in which specific amounts of vulcanization can be achieved to achieve complete vulcanization without actually uncuring or over-curing. Can be used in any other product that requires heat.

(2) Prior Art Tire vulcanization typically involves a reservoir device for inflating the tire with a hot fluid medium (usually steam or boiling water) and a heated mold that receives the unvulcanized or green tire carcass. Performed in a press. The press has the effect of forming the tire into the desired final shape in a trend pattern and hardens the assembly while causing sulfurization by the heat pumped into the tire from the moult and liquid medium.

Prior art systems for controlling vulcanization began by simply holding the tire in a heated press for an empirically determined period of time. More recent techniques have been developed to calculate the "vulcanization trophic" (i.e. mid-heat),
Once the requested amount of "heating level" has been put in, the process ends. This technology is based on the process of determining the number of points at a predetermined point, which is monitored by a small temperature sensor installed inside the tire.Similarly, the temperature outside the tire only l]llI,
Iteratively calculate the median vulcanization number along the line of imagination l=, which is located at the shoulder of the tire.
1 No. 4371483 (: proposed by the specification.

The minimum vulcanization point on that line is then selected and its l1l
The press opens when the requested vulcanization level is accepted.

The traditional method of calculating the extent of vulcanization (i.e., the number of vulcanized units received) at one +7- measurement point is a fairly unreliable, accurate approximation, requiring a large amount of complex calculations. ,i
Recently, this force has been revised and can be used to simplify the i'i'l calculation for each tire in the repeated tire vulcanization process. Efforts have been made to discover algorithms for -.

Such an algorithm is described in US Pat. No. 4,371 mentioned above.
483 Bow details, 1? It is used in -C.

(3) E1 of the Invention The first object of the present invention is to control the vulcanization of products such as tires, requiring only limited computer functionality, such as can be easily performed on already available microcomputers. The object of the present invention is to provide a further improved method. The second purpose is to maintain the same tire arrangement and structure even though the working conditions change from one tire to another.
It is an object of the present invention to provide a method for accurately adjusting the vulcanization time and thereby accommodating changes in the initial temperature of the green tire and mold.

(4) Structure of the Invention In achieving these objectives, we have addressed the problem that no single identified algorithm can cope with the widely varying critical temperatures and, therefore, widely varying times required to reach complete vulcanization. borrowed money. For example, l l,
In the example of a 00-'22.5 radial truck tire,
Adjustment of the 35-60 minute vulcanization time had to be assisted by empirically varying the initial conditions in the manufacturing environment. However, if the set of values is given as a constant, so that a series of similar algorithms can be used, this algorithm can be used to modify the vulcanization process.

According to the invention, the method of vulcanizing a product to be vulcanized by heating includes placing the product in a press mold heated by a medium, heating the product to press the product and start vulcanization. It involves filling the interior of the product with a fluid medium under pressure in order to do so, and is characterized by the following steps:

(a) Monitoring the temperature of the mold 〒 Cb) Measuring the time t to reach the maximum mold temperature: (C) Monitoring the temperature TMw of the medium heating the mould.

(d> Monitor the odor of the hot fluid medium after the initial or basic vulcanization time, logec: A
1 L + A 2 L L m 3 t L
Tm + A 4T - A tL MS 5tLTMs + A6tL L (C is the pain received after the 11 stomach ffl t L from the start of vulcanization, 'AJ number A, ltL, shout/dan...dan/ A6
tL is selected from a set of constants, each set of which is applied for a given time interval during vulcanization;
The set selected for each computation is the predetermined I
Vulcanization accepted by this minimum vulcanization point for each elapsed vulcanization time for tk small vulcanization point! ``Calculating the 1i-place number repeatedly.

(e) Comparing each of the calculated vulcanization trophies to the known number of vulcanization units and the minimum vulcanization point for a complete and accurate 4JE; (f) the calculated vulcanization units; (g) Removing the product from the moult.

'>'+l M's sen) is determined by performing a detailed finite element analysis on the transverse section 1J1i of the lined product into sheets using the marker technique. Techniques in the book are, for example, techniques published in public magazines such as [Application of the finite concavity method to heat flow in com products J (GD Hynbard and GM Simpson, Bulletin "International Rubber Association" 1979φ Penis). It is. These calculations are complex and require the power of a large computer or for the product to be vulcanized.

-11 real(i) yields a set of results for which the exact 11'l is obtained by choosing separate II!j intervals and fitting the curve for these time intervals.
A j-line regression fit is achieved. A suitable interval is 5 minutes, and for this name 5 minutes, the constant cent, AltL...
A6tL is discovered. Parts of the present invention may include such intervals or, when used with 1F definite constant cents, 1
1- A good vulcanization time can be determined by a+++, which does not require a large total capacity at the press site. In fact, the cent of each constant is the total sum Wt! over the determined temperature. l
Clear calculation of i-place becomes +11 ability.

For example, for 1 minute of 6 pulses (1), it is sufficient to change the constant for each 5 minute interval.

When curing tires, what about moulding? :11
Preferably, f I^T is measured by a dedicated pair located within the body of the mold adjacent to the surface of the tire.

Furthermore, the temperature TMS of the %α body heating the mould is determined by the temperature of the steam measured at the point of entry into the mold, and the temperature TMW of the fluid in the product leaving the tire 71
Preferably, the temperature of the hot water is measured at 11 points.

Further details of the invention and in particular the deviations of the set of constants will appear from the description below. This is the product name 5P311
1 is an example of a vulcanization control method for an all-steel radial 12.00-20 truck tire manufactured by Dunlop Co., Ltd., sold under the trade name.

(5) Description of Examples First, a finite concavity analysis is performed on a cross-section of a tire using the mesh shown in the drawings. There, half of the cross-sectional view of the tire is divided into a large number of triangles 10, the apex of which is the radial A111 point. Assume that the heat flow through each pentagon is linear and that the properties of the elements are as shown in Table 1.

Table 1 Elements/Materials Thermal conductivity Thermal diffusivity Ic (W/m'C) k'(m'/'s) Tire tread/rubber 0, 25 0.131J Tomibo 6 steel wire/rubber composite 0, 37 0.121xlG-6 The initial condition is 25°c-too@ for the carcass temperature.
c. The mold temperature varied from 100"C to 150"C. The degree of vulcanization after removing from the mold is 20
Limited to minutes.

Calculations were performed for different mold patterns, surface temperatures, and internal fluid temperatures.

Many different calculations are performed and the set of constants A1tL
......Statistical analysis was performed using multiple regression procedures to yield A6tL. One set is 35-40 minutes, 40-45 minutes, 45-50 minutes respectively.
Minutes, 50-55 minutes, 55-60 minutes, for! I got p. A set of these five constants was found to cover all possible vulcanization conditions for compression based on 5 minute intervals of 1 minute.

Constants are shown in Table 2 for exemplary tires.

Table 2 Tire Size 12.00-20 Product Name Equation Constant Equation Number for SP311 Constant + 2 1 A = -0,1210x10 1 = l A = +0.1819xlO 5 A = +0.1387 6 2 A = -0 , 1138xlO+2 1 A = +0.1931xlO-' 5 A = +0.1142 6 + 2 3 A = -0,1065xlO 1 A = -0,7633xlO-2 2 A = +0.5665xlO-2 3 l A = +0.2437xlO 4 A = +0.2016xlO-' 5 A +0. 9468 6 A = -0,6398xlO"-" 2 A = +0.4921xlO-2 3 A = 0.2533xlO-' 4 l A = +0.2080x10 5 l A = +0.7989x10 46 Value 5 A = -0, 9511xlO" 1 A = +0.4147xlO" 3 l A = +0.2605xlO 4 A = +0.2131xlO-1 5 A = +0.6773xlO' 6 Calculations using the algorithm then give the vulcanization units.

Here, l 71io sulfur unit = 140” C (413,
1 minute at 15K). A suitable algorithm is shown in Table 3.

Table 3 Equation 1. 35-40 minutes: log C=All+A12tm+A13Tm+A14
"Ms + A15" MW + A16'L force equation 2, 40-
1Og for 45 minutes C=A21+A22tm+A23Tm+A24
TMS+A25TMW+A26tL Equation 3. 45-
1Og for 50 minutes C=A31+A32tnl+A33Tm+A3
4TMS+A35TMW+A36tL Equation 4. 50
-55 minutes log C=A41+A42tm+A43Tm+A44
TMS+A45TMW+A46tL Equation 5. 55-
1Og for 60 minutes C=A51+A52tm+A53Tm+A54
TMS+A55TMW+A36tL However, C=vulcanization t after 1L of time=time until the maximum mold temperature is reached T=mold surface temperature TMS"Steam temperature TMW=hot water temperature t=time from the start of vulcanization.

The finite element analysis also indicates the minimum vulcanization point for the tire concerned.

Following the induction of constants for the algorithm, the tire curing press is connected to a microcomputer equipped with thermocouple power from the press to deliver the temperatures and times required by the algorithm. Then, the required number of vulcanization units for the minimum vulcanization point for accurate vulcanization without over or under vulcanization is input as a target value, and the tire is set in the press Mj.
It will be done.

Time cycle 11 starts at 0 when the bag is inflated and the press is closed for final tire molding. The steam and hot water temperatures T and TMwS and the mold surface temperature T and time tM were monitored and after 35 minutes a first C calculation was performed using the first set of constants in the algorithm. Calculations were made every minute by a microcomputer, comparing the results of each number of vulcanization units with the target value.

At 40 minutes, the microcomputer is changed to use the second constant, and thereafter the constant is changed sequentially at every 5 minute interval.

When the calculated value of the vulcanization units introduced at the minimum vulcanization point equals or exceeds the target value, the microcomputer opens the press and begins to remove the tire and stops applying heat.

Such a method of controlling the vulcanization process has been shown to achieve controlled and precise vulcanization despite large differences in temperature in the press and initial temperature of the elements.

This method uses limited computer power on the press, resulting in cost savings, which makes it possible to successfully use it on tires ranging from other truck tires to car tires.

[Brief explanation of drawings]

The figure is an explanatory diagram showing the formation of zones in the cross section of a tire. lO・・・・・・　-mirror (Sodanu 2

Claims (6)

[Claims] (1) placing the product in a press mold heated by a medium and filling the interior of the product with a hot pressurized fluid medium to compress and heat the product to initiate vulcanization; A method for vulcanizing a product comprising the steps of (a) monitoring the temperature T of the mold, (b) measuring 1f11 t when the maximum mold temperature is reached, and (c
) monitoring the temperature value TMs of the medium heating the mold; 1) monitoring the temperature value TMs of the hot fluid medium after the initial or vulcanization time;
=A+A t+A ltL 2tL m 3tLTm+A4T +A T
+A tL MS 5tL MW 6tLtL (where C is the vulcanization received after 1L of time from the start of vulcanization, and the constant AltL ,...
A6tL is selected from a series of sets of constants, each set of which is applied for a time interval of Jj- during vulcanization, and the set selected for each calculation is equal to the calculation time tL.
cents for the previous interval. ) for a predetermined minimum cure point in the product, the number of cure units accepted by this minimum cure point for each elapsed cure time. (e) the known number of vulcanization units and the ri- of vulcanization units for a minimum vulcanization point for a complete 1F accurate vulcanization;
(f) terminating the vulcanization if the calculated mid-cure reaches the number of complete vulcanization; and (g) removing the product from the mold. a method of vulcanizing a heated vulcanized product, the method comprising: removing a heated vulcanized product; (2) The constants are determined by performing IJ finite element analysis to obtain the curve of vulcanization on the cross section of the product, selecting a series of separate time intervals and fitting the curve to each time interval. 2. A method as claimed in claim 1, in which an accurate regression fit is obtained by (3) The method according to claim 1, wherein the temperature T of the mold is determined by a thermocouple located in the mold adjacent to the surface of the product. (4) The method according to claim 1, 2-1, or 3-j, wherein the temperature TMS of the liquid that heats the mold is measured by measuring the temperature of the liquid flowing into the mold. (5) The method according to any one of claims 1 to 4, wherein the temperature TMW of the liquid in the product is measured by a thermocouple at a measuring point where the liquid covers the product. (6) The product to be vulcanized is vulcanized in the evening, the liquid for heating the mould is red air, and the liquid for cooling the tire is hot water. The method described in any one of the preceding sections.