JP5032735B2 - Method for predicting equivalent vulcanization degree and method for producing rubber product - Google Patents

Description

  The present invention relates to a technique for predicting an equivalent vulcanization degree when rubber is vulcanized and predicting a rubber blow point.

  In manufacturing thick rubber products that require vulcanization, such as tires, one method of determining the vulcanization time is to calculate the temperature distribution due to heat conduction and then calculate the vulcanization reaction rate. A technique for predicting the degree of progress of the vulcanization reaction by integration is known. As such a technique, for example, a technique disclosed in Patent Document 1 is known.

Japanese Patent Laid-Open No. 7-40355

  By the way, a tread pattern is formed by grooves and blocks on the surface of the tire. Further, the thickness in the meridional section of the tire is often not uniform. As described above, since the tire has a complicated shape, two-dimensional or three-dimensional heat conduction / vulcanization reactivity analysis is required to apply the above method. This complicates the analysis procedure when predicting the degree of progress of the vulcanization reaction, and requires skill to set boundary conditions and to model the analysis target portion. As a result, there is a problem that handling is difficult and versatility is lowered. Furthermore, when the heat conduction / vulcanization reactivity analysis is performed in two dimensions and three dimensions, the calculation amount increases accordingly. As a result, there is also a problem that it takes a lot of time until the calculation converges and the prediction result is obtained.

Accordingly, the present invention has been made in view of the above, and it is possible to easily handle the equivalent vulcanization degree at the time of prediction, and to reduce the time until obtaining the prediction result, and a method for predicting the equivalent vulcanization degree. an object of the present invention is to provide a process for the production of fine rubber products.

In order to achieve the above-mentioned object, the equivalent vulcanization degree predicting method according to the present invention is such that the computer changes the block width w and the groove depth t, which are parameters representing the shape of the surface shape of the rubber product. And obtaining a plurality of first slowest vulcanization curves corresponding to different values of the parameters w and t in the cross section including the slowest vulcanization portion of the rubber product by two-dimensional heat conduction / vulcanization reactivity analysis. In response to different values of parameters representing the dimension / thickness L of the cross section in the heat flow direction in the cross section, a plurality of second slowest additions in the cross section are obtained by one-dimensional heat conduction / vulcanization reactivity analysis. procedures and from the corresponding relationship between the plurality of first slowest vulcanization curve and the plurality of second slowest vulcanization curve, before Kipa parameters w, and t, dimensions and thickness of the cross-section for obtaining the vulcanization curve reduction represents a decrease in the amount ΔL of L Atsupa A step of obtaining an approximate function of the meter [Delta] L / t, the equivalent degree of vulcanization prediction target rubber products before Kipa parameter w, the value of the reduced thickness parameter [Delta] L / t corresponding to the value of t obtained from the approximate function, By executing the one-dimensional heat conduction / vulcanization reactivity analysis in the cross section including the slowest vulcanization portion of the rubber product subject to prediction of the equivalent vulcanization degree, using the obtained thickness reduction parameter ΔL / t A computer program describing a procedure for predicting an equivalent vulcanization degree in the latest vulcanization part of the rubber product is executed.

  This equivalent vulcanization degree prediction method can be analyzed by one-dimensional heat conduction / vulcanization reactivity analysis even for a two-dimensional shape by using an approximate function of a surface shape parameter and a thickness reduction parameter. . This facilitates the setting of boundary conditions and the creation of an analysis model, so that handling in heat conduction / vulcanization reactivity analysis can be facilitated. Moreover, since the amount of calculation can be suppressed by the analysis in one dimension, the time until obtaining the prediction result can be shortened.

Further, the following equivalent vulcanization degree prediction method according to the present invention is the equivalent vulcanization degree prediction method, wherein the equivalent vulcanization degree prediction target rubber product has a groove depth t on the surface of the target rubber product. A planar shape is extracted and converted into a thermally conductive equivalent rectangle, the long side length wl and the short side length ws are used as parameters representing the surface shape, and the long side length wl, One of the short side lengths ws is defined as a block width, and the corresponding first thickness reduction amount ΔL1 is obtained from the approximate function, then the groove depth is set to t−ΔL1, and the long side length wl, the short side The value of the second thickness reduction amount ΔL2 corresponding to the other length ws of the block width is obtained from the approximation function, and the equivalent vulcanization degree prediction target rubber is obtained using the obtained value of the second thickness reduction amount ΔL2. Perform one-dimensional heat conduction and vulcanization reactivity analysis in the cross section including the latest vulcanization part of the product Accordingly, characterized in that predicting the equivalent degree of vulcanization of the slowest pressurized 硫部 content of the rubber products.

  This equivalent vulcanization degree prediction method uses a three-dimensional rubber product as a two-dimensional shape when the parameter representing the surface shape of the rubber product is greater than or equal to a predetermined value, and uses an approximate function. Thus, it can be analyzed by one-dimensional heat conduction / vulcanization reactivity analysis. This facilitates the setting of boundary conditions and the creation of an analysis model. Therefore, even when the rubber product has a three-dimensional shape, the handling in the heat conduction / vulcanization reactivity analysis can be facilitated. Moreover, since the amount of calculation can be suppressed by the analysis in one dimension, the time until obtaining the prediction result can be shortened.

Further, the equivalent vulcanization degree prediction method according to the present invention is the same as the equivalent vulcanization degree prediction method, wherein the planar shape of the block of the surface of the equivalent vulcanization degree prediction target rubber product is extracted, and the heat conduction is extracted. Are converted into equivalent rectangles, the long side length wl and the short side length ws are used as parameters representing the surface shape, and the long / short ratio wl / ws is obtained. The long / short ratio wl / ws is a predetermined value. In the case of the following, the value of the corresponding first thickness reduction ΔL1 is obtained from the approximate function using one of the long side length wl and the short side length ws as a block width, and then the groove depth is determined. The value of the second thickness reduction amount ΔL2 corresponding to the length of the long side w1 and the other side of the short side length ws as the block width is obtained from the approximate function, and the obtained second thickness reduction amount Using the value of ΔL2, the latest vulcanized portion of the rubber product subject to prediction of the equivalent vulcanization degree is determined. A one-dimensional heat conduction / vulcanization reactivity analysis is performed within the cross section, and the cross section including the latest vulcanization portion of the rubber product for which the long / short ratio wl / ws is not less than a predetermined value and the equivalent vulcanization degree prediction target rubber product is one. In the case where the two-dimensional shape can be handled, the thickness reduction parameter ΔL / corresponding to the short side length ws as the block width is obtained without obtaining the thickness reduction parameter value corresponding to the long side length wl. The value of t is obtained from the approximate function, and the obtained value of the thickness reduction parameter ΔL / t is used to determine the one-dimensional heat conduction in the cross section including the latest vulcanization portion of the rubber product to be predicted for equivalent vulcanization degree. By performing vulcanization reactivity analysis, the equivalent vulcanization degree in the latest vulcanization part of the rubber product is predicted.

  This equivalent vulcanization degree predicting method is such that, when the parameter representing the surface shape of the rubber product is less than a predetermined value, the influence of the parameter representing the surface shape on the vulcanization time is taken into consideration. Treat the product as a two-dimensional shape. And by using an approximate function, it can be analyzed by one-dimensional heat conduction / vulcanization reactivity analysis. This facilitates the setting of boundary conditions and the creation of an analysis model. Therefore, even when the rubber product has a three-dimensional shape, the handling in the heat conduction / vulcanization reactivity analysis can be facilitated. Moreover, since the amount of calculation can be suppressed by the analysis in one dimension, the time until obtaining the prediction result can be shortened.

  A computer program for predicting an equivalent vulcanization degree according to the present invention executes the method for predicting the equivalent vulcanization degree. Thereby, the prediction method of the above-mentioned equivalent vulcanization degree is realizable using a computer.

  Also, the following rubber product manufacturing method according to the present invention predicts the equivalent vulcanization degree of the rubber product to be vulcanized by the above-mentioned equivalent vulcanization degree prediction method, and vulcanizes it from the predicted equivalent vulcanization degree. It includes a procedure for predicting a blow point of a rubber product, a procedure for starting vulcanization in a vulcanization mold, and a procedure for ending vulcanization at the predicted blow point and demolding. .

  In this rubber product manufacturing method, the equivalent vulcanization degree of the rubber product to be vulcanized is predicted by the above-described method for predicting the equivalent vulcanization degree, and the blow point of the rubber product to be vulcanized is predicted from the predicted equivalent vulcanization degree. . Thereby, since a blow point can be predicted simply and quickly, a blow point can be efficiently obtained even in a manufacturing situation where BPs of various types of tires must be managed. As a result, the production efficiency of the rubber product is improved and the yield is also improved.

The manufacturing method of the prediction method及Beauty rubber products equivalent vulcanization degree according to the present invention, it is possible to facilitate handling at the time of the prediction of equivalent degree of vulcanization, it is possible to shorten the time for obtaining a prediction result.

  Hereinafter, the present invention will be described in detail with reference to the drawings. The present invention is not limited to the best mode for carrying out the invention described below. In addition, constituent elements in the following embodiments include those that can be easily assumed by those skilled in the art or those that are substantially the same. The present invention can be suitably applied when predicting the equivalent vulcanization degree of rubber constituting a tire, and can be suitably applied to general tires regardless of whether they are pneumatic tires, passenger car tires, or heavy duty tires. Furthermore, the present invention is not limited to tires in general, and can be suitably applied to rubber products in general that require rubber vulcanization, such as conveyor belts and fenders. In the following description, a tire is used as an example of a rubber product.

  The method for predicting the equivalent vulcanization degree according to Example 1 is characterized by the following points. That is, in the cross section including the slowest vulcanization part of the rubber product, the slowest vulcanization curve obtained by one-dimensional heat conduction and vulcanization reactivity analysis and a plurality of conditions that represent the actual vulcanization of the rubber product are strictly observed. Using the fact that the latest vulcanization curve obtained by calculation is almost equivalent, an approximate function that relates the two is obtained. Then, using this approximate relationship, the equivalent vulcanization degree prediction target rubber product is analyzed by one-dimensional heat conduction / vulcanization reactivity analysis to predict the equivalent vulcanization degree, and the rubber product obtained from the prediction result is analyzed. Predict the blow point in the slowest vulcanization part.

  Before explaining the equivalent vulcanization degree prediction method according to the first embodiment, the latest vulcanization curve will be explained. When rubber products such as tires and conveyor belts are vulcanized, rubber has a poor thermal conductivity, and therefore the vulcanization tends to be slower toward the inside of the product. For this reason, the degree of vulcanization varies depending on the location of the rubber product. During the vulcanization, the slowest part of the vulcanization and the slowest degree of vulcanization (the degree of vulcanization in that part) can be defined. The slowest vulcanization curve is a function of time obtained by plotting the slowest degree of vulcanization against vulcanization time.

  At the initial stage of vulcanization, the slowest vulcanization part is all the part having a low temperature, but as the heat conduction progresses, it becomes located in a deep part of the rubber. As time further elapses, if there is a temperature difference in the mold, the slowest vulcanization portion moves to the lowest temperature portion of the mold. One of the methods for obtaining the slowest vulcanization curve is to first calculate the temperature curve (temporal change in temperature) by solving the heat conduction at various positions of the rubber product, calculate the crosslinking reaction rate according to the temperature, and equivalent Obtain the vulcanization curve that represents the degree of vulcanization, then repeat the vulcanization curve at each position of the product and enclose the lowest part of multiple vulcanization curves to obtain the slowest vulcanization curve Can do.

  A method for predicting the equivalent vulcanization degree according to the first embodiment will be described. FIG. 1 is a partial cross-sectional view showing a partial cross section including a meridian surface of a tire which is an example of a rubber product. In the tire 1 which is an example of a rubber product, the tread surface 5 is in contact with the ground. A plurality of grooves 2 and a plurality of blocks 3 are formed on the tread surface 5. A tread pattern is formed on the tread surface 5 by the plurality of grooves 2 and the plurality of blocks 3.

  FIG. 2-1 is a partial cross-sectional view in which a part of the tread surface of the tire is enlarged. The dimension of the block 3 formed in the tread surface 5 of the tire 1 is demonstrated using FIGS. The distance between the bottom 2u of the groove 2 and the top 3t of the block 3 is the block height or groove depth and is represented by t. Further, the width of the block 3 is defined as a block width and is represented by w. In FIG. 2A, the width of the block 3 in the width direction of the tire 1 (Z direction in FIG. 1) in the meridional section of the tire 1 is the block width, but if necessary, the circumferential direction of the tire 1 The width of the block 3 in FIG. The distance between the tire inner surface 4 of the tire 1 and the top 3t of the block 3 is referred to as the total thickness of the tire 1 and is represented by L. In the tire 1, the thickness direction of the tire 1 is substantially equal to the direction of the heat flow supplied from the heat source during vulcanization. Here, the block groove depth t (height t) and the block width w are parameters representing the surface shape of the rubber product. Further, the total thickness L of the tire 1 is a parameter representing the dimension of the cross section including the latest vulcanized portion of the rubber product.

  Next, the equivalent vulcanization degree, the latest vulcanization point and the blow point of rubber will be described. FIG. 2-2 is an explanatory view showing a change of the equivalent vulcanization degree with respect to time. The equivalent vulcanization degree (K) is a scale indicating the degree of progress of the vulcanization reaction of rubber, and can be obtained from the history of the temperature applied to the rubber for vulcanization, for example. The blow point (hereinafter referred to as BP) refers to the time during which rubber does not foam from the start of vulcanization to the end of vulcanization, that is, when the heating is terminated. Generally, the vulcanization time T30 when the equivalent vulcanization degree reaches 30% is defined as BP (see FIG. 2-2). In addition, even if it is the same kind of rubber product, BP changes with the compounding ratio and mixing state of rubber.

  FIG. 3 is an explanatory diagram of the latest vulcanization point of the tire. When a so-called green tire is placed in a vulcanization mold and vulcanized, a tread pattern formed on the inner surface of the vulcanization mold is transferred to the tread surface 5 side. In the vulcanization of the green tire, a heat quantity Q is applied from the tread surface 5 side and the tire inner surface 4 side to heat the green tire in the vulcanization mold. That is, in vulcanization, a heat source exists on the tread surface 5 side of the tire 1 and the tire inner surface 4 side of the tire 1.

  In general, in a rubber product that requires vulcanization, vulcanization is most difficult to proceed in the vicinity of the center between both heat sources in a portion sandwiched between the heat sources. This portion is called the latest vulcanization point, and in vulcanization of the tire 1, it is often near the middle between the tread surface 5 and the tire inner surface 4 of the tire 1. In FIG. 3, the portion indicated by Psl is the latest vulcanization point of the tire 1. BP at the latest vulcanization point is used as an index for demolding. Ideally, when the latest vulcanization point Psl reaches BP, the tire 1 is demolded from the vulcanization mold. When the heating temperature is different between heat sources as in the case of vulcanizing a tire, the latest vulcanization point often shifts to the heat source side having a lower temperature.

  The BP of a rubber product can be obtained by exact calculation using a finite element method or the like. However, in this method, the calculation procedure, setting of boundary conditions, and the like are complicated, and calculation time is also required. Further, in manufacturing a rubber product, it is only necessary to obtain BP at the latest vulcanization point. However, in strict calculation, BP in other parts is also obtained, which is not economical for calculation.

  Since the heat conduction phenomenon proceeds in a direction in which the temperature difference becomes zero, the fine temperature change in the vicinity of the tire surface layer is alleviated until reaching the inside of the tire to be vulcanized, and a slow temperature change is generated inside the tire. It is only transmitted. Further, the vulcanization reaction corresponding to the temperature change is added and accumulated. This accumulated amount corresponds to the equivalent vulcanization degree. Therefore, even if the temperature inside the tire changes slightly in response to the temperature change in the vicinity of the tire surface layer, it hardly affects the equivalent vulcanization degree.

  As a result of intensive studies, the present inventors have paid attention to this point, and the change in the equivalent vulcanization degree with respect to time at the latest vulcanization point existing inside the tire strictly takes into consideration the shape and boundary conditions of the tire surface 2 It was found that the shape approximated by one obtained by one-dimensional heat conduction / vulcanization reactivity analysis and one obtained by one-dimensional heat conduction / vulcanization reactivity analysis. From this relationship, an approximate function that correlates the two is obtained, and using this approximate relationship, one-dimensional heat conduction / vulcanization reactivity analysis is performed on the rubber product to be predicted for the equivalent vulcanization degree. Thereby, it came to complete the prediction method of the equivalent vulcanization degree which concerns on Example 1 which can obtain | require BP in the latest vulcanization point simply and rapidly. This will be described in detail next. In the following description, please refer to FIGS.

  FIG. 4A is an explanatory diagram illustrating a first slowest vulcanization curve that is strictly calculated by two-dimensional heat conduction / vulcanization reactivity analysis. The first slowest vulcanization curve is a plot of the change in the equivalent vulcanization degree K with respect to the vulcanization time T at the slowest vulcanization point of the tire. The first slowest vulcanization curves A0 to A6 are analysis results when the block width w is changed with the groove depth t being constant. The total thickness L was 20 mm. The first slowest vulcanization curve A0 is a case where the groove 2 does not exist on the tread surface 5. In this case, the groove depth t and the block width are 0, and the total thickness L is 20 mm. Here, changing w / t means changing the depth of the groove 2 formed in the tread surface 5 of the tire 1 and the width of the block 3. Therefore, when w / t is changed, it is possible to consider the influence of the tread pattern formed on the tread surface 5 of the tire 1 on the heat transfer characteristics.

FIG. 4-2 is an example of an analysis model used for two-dimensional heat conduction / vulcanization reactivity analysis. The first slowest vulcanization curves A0 to A6 shown in FIG. 4-1 are obtained by dividing the meridional section of the tire 1 with a lattice as shown in FIG. 4-2, and using a finite element method, a finite difference method, or other analysis methods. By performing a two-dimensional heat conduction and vulcanization reactivity analysis. At this time, the temperature of the tread surface 5 is θ _1, and the temperature of the tire inner surface 4 of the tire 1 is θ ₂ .

  FIG. 5A is an explanatory diagram showing a second slowest vulcanization curve analyzed by one-dimensional heat conduction / vulcanization reactivity analysis. These second slowest vulcanization curves are plots of changes in the equivalent vulcanization degree K with respect to the vulcanization time T in the slowest vulcanization portion of the tire. These second slowest vulcanization curves are the analysis results when the total thickness L is changed in a state where the groove 2 does not exist on the tread surface 5, that is, the groove depth t and the block width are set to 0. is there. The total thickness L is changed in the range of 20 mm to 13 mm. The total thickness L of the second slowest vulcanization curve B0 is 20 mm, and the second slowest vulcanization curve B0 coincides with the slowest vulcanization curve A0 shown in FIG.

FIG. 5-2 is an example of an analysis model used for one-dimensional heat conduction / vulcanization reactivity analysis. The second slowest vulcanization curve shown in FIG. 5A indicates that the temperature of the tread surface 5 is θ ₁ and the tire inner surface 4 with respect to the meridional section of the tire 1 in a state where the groove 2 does not exist on the tread surface 5. as the temperature theta _2, determined by performing a one-dimensional heat conduction vulcanization reactivity analysis. At this time, the total thickness L is changed as described above.

  In both the two-dimensional and one-dimensional heat conduction / vulcanization reactivity analyses, the activation energy, which is an index of the temperature dependence of the vulcanization reaction, was 20 kcal / mol. Here, in the range of 15 kcal / mol to 25 kcal / mol which is the activation energy in the actual rubber, the shapes of the first and second slowest vulcanization curves and their positions are compared with the state shown in FIG. And hardly change. In both two-dimensional and one-dimensional heat conduction and vulcanization reactivity analyses, if the thermal diffusivity is changed within the actual rubber range, the first and second slowest vulcanization curves move in the time axis direction. However, it moves while maintaining the relative positional relationship between the first and second slowest vulcanization curves.

Here, the equivalent degree of vulcanization K ₁ in Figure 4-1, is the equivalent degree of vulcanization K ₁ in Figure 5-1 the same value.

FIG. 6 is an explanatory diagram showing a state in which the first and second slowest vulcanization curves analyzed by two-dimensional and one-dimensional heat conduction / vulcanization reactivity analysis are overlapped. As shown in FIG. 6, the first slowest vulcanization curve obtained by changing the surface shape parameter w / t (hereinafter referred to as w / t) in the two-dimensional heat conduction / vulcanization reactivity analysis and the one-dimensional heat conduction. It can be seen that the second slowest vulcanization curve obtained by changing the total thickness L in the vulcanization reactivity analysis has substantially the same shape. The first slowest vulcanization curves A0 to A6 obtained by changing w / t by two-dimensional heat conduction / vulcanization reactivity analysis are used to calculate the total thickness L by one-dimensional heat conduction / vulcanization reactivity analysis. It can be seen that the second slowest vulcanization curves B0 and other values obtained by changing the values almost coincide with each other .

  When the vulcanization time T is further increased and the vulcanization is further advanced, the first slowest vulcanization curve obtained by the two-dimensional heat conduction / vulcanization reactivity analysis and the one-dimensional heat conduction / vulcanization are obtained. It is expected that the deviation from the second slowest vulcanization curve obtained by the sulfur reactivity analysis will increase. However, in actual vulcanization, BP is reached within several times the time when vulcanization is substantially started (intercept between the first and second latest vulcanization curves and the time axis). Therefore, in the range of time to reach BP, the first slowest vulcanization curve obtained by the two-dimensional heat conduction / vulcanization reactivity analysis and the second highest vulcanization curve obtained by the one-dimensional heat conduction / vulcanization reactivity analysis. The isomorphism with the slow vulcanization curve is sufficiently maintained.

  From the above results, the first slowest vulcanization curve obtained by changing w / t in the two-dimensional heat conduction / vulcanization reactivity analysis shows the total thickness L in the one-dimensional heat conduction / vulcanization reactivity analysis. This can be represented by the second slowest vulcanization curve obtained by changing the value. This means that the heat transfer characteristics when the tread pattern is changed are almost the same as the heat transfer characteristics when the total thickness L is obtained by one-dimensional heat conduction / vulcanization reactivity analysis. means. That is, the thickness is reduced from the total thickness L of the tire by a thickness reduction amount ΔL corresponding to w / t of the tread surface 5, and the one-dimensional heat conduction / vulcanization is performed with respect to the reduced total thickness (L−ΔL). A reactivity analysis is performed to determine the second slowest vulcanization curve. Then, the equivalent vulcanization degree can be predicted and the BP can be predicted by the second latest vulcanization curve.

FIG. 7 is an explanatory diagram showing the relationship between the thickness reduction parameter and w / t by logarithmically displaying the horizontal axis. As shown in FIG. 7, when the relationship between w / t and the thickness reduction parameter ΔL / t shown in Table 1 is plotted, the relationship shown by the thin solid line in FIG. 7 is obtained. Here, this relationship is expressed by the approximate expression (1).
ΔL / t = 0.45 × ln (w / t) −0.86 (1)

The sloped portion of the thick solid line in FIG. 7, that is, the straight line represented by the approximate expression (2), is moved so that the thinning amount ΔL becomes smaller than the straight line obtained from the relationship between ΔL / t and w / t. It is a thing. Reducing the thickness reduction ΔL means that the slowest vulcanization curve based on the one-dimensional heat conduction / vulcanization reactivity analysis moves to the right with respect to the time axis shown in FIG. This means that it takes longer time to reach the BP than the latest vulcanization curve obtained from the approximate expression (1). As a result, the BP can be predicted by obtaining the latest vulcanization curve on the safe side, that is, by suppressing the risk of vulcanization ending in a state where the BP has not been reached.
ΔL / t = 0.45 × ln (w / t) −0.75 (2)

  When w, t, L, etc. are changed within a range that can be actually used in passenger car tires and verified, the slowest vulcanization curve is obtained on the safe side according to the above approximate expression (2). Was able to predict. Note that the degree to which the approximate expression (1) is shifted to the safe side may be changed depending on the accuracy of the calculation model. In the heavy load tire, the block width w and the groove depth t, which are parameters representing the surface shape within a range that the tire can be actually adopted, and the total thickness L, which is a parameter representing the dimensions of the cross section. Etc. can be changed to obtain an approximate expression of the thickness reduction parameters ΔL / t and w / t.

  In FIG. 7, the fact that the thickness reduction parameter shown on the vertical axis is 0 means that the one-dimensional heat conduction / vulcanization reactivity analysis is executed with the total thickness L of the tire. This means that the influence of the groove 2 formed on the tread surface 5 is small enough to be ignored in terms of heat conduction and vulcanization reaction. Moreover, the thickness reduction parameter shown on the vertical axis being -1 means that no rubber is present on the groove 2. Also, performing two-dimensional heat conduction / vulcanization reactivity analysis in a state where there is no rubber on the groove 2 and the groove bottom is in contact with the heat source at the height (Lt: FIG. 2-1); It means that performing the one-dimensional heat conduction / vulcanization reactivity analysis in the state where there is no groove 2 and the thickness reduction amount ΔL = t is equivalent. Thus, the thickness reduction parameter ΔL / t is in the range from −1 to 0.

  If calculated strictly, the approximate expression (1) and the approximate expression (2) asymptotically approximate to ΔL / t = 0 or −1 by a change in w / t, but as shown in FIG. The broken line approximation can be used practically. As an approximate expression representing the relationship between w / t and ΔL / t that is a thickness reduction parameter used in this case, either of the above approximate expressions (1) or (2) may be used. Uses approximate formula (2) in consideration of safety.

When w / t is greater than the intercept between the approximate expression (2) and w / t axis at ΔL / t = 0, ΔL / t = 0, that is, there is no groove 2 and the total thickness L The equivalent vulcanization degree can be predicted by executing a one-dimensional heat conduction / vulcanization reactivity analysis. In addition, when w / t is smaller than the intercept of the approximate expression (2) at ΔL / t = −1 and the w / t axis, ΔL / t = −1, that is, there is no groove 2 and the total thickness The equivalent vulcanization degree can be predicted by executing one-dimensional heat conduction / vulcanization reactivity analysis with the length Lt. In other ranges, the equivalent vulcanization degree is predicted by obtaining the thickness reduction amount ΔL by the above approximate expression (2) and performing a one-dimensional heat conduction / vulcanization reactivity analysis with the total thickness L−ΔL. it can be.

If Example Ebamizo 2 also block width is more than about 5.5 times the groove depth t as exists, in the absence of the groove 2, and one-dimensional heat conduction, the vulcanization reaction in a state of total thickness L By performing the degree analysis, the equivalent vulcanization degree can be predicted. For example, even if the groove 2 exists, if the block width w is about 0.6 times or less the groove depth t, the one-dimensional heat conduction is performed without the groove 2 and with the total thickness Lt.・ Equivalent vulcanization degree can be predicted by executing vulcanization reactivity analysis.

Thus, in the prediction method of the equivalent degree of vulcanization according to the first embodiment, if found and block width w and groove depth t of the tire 1, it is possible to obtain a reduced Atsuryou [Delta] L. Then, by executing the one-dimensional heat conduction / vulcanization reactivity analysis in a state where the total thickness L of the tire 1 is reduced by ΔL, it is possible to easily obtain the latest vulcanization curve and predict BP. . This eliminates the need for complicated strict heat conduction / vulcanization reactivity analysis and makes it possible to easily predict BP with sufficient practical accuracy. In addition, the calculation amount can be greatly reduced by one-dimensional heat conduction / vulcanization reactivity analysis, so that the calculation time can be shortened.

  Here, in Example 1, the temperature boundary condition is constant for the sake of simplicity. However, in the exact calculation (two-dimensional heat conduction / vulcanization reactivity analysis) used in the above description, the prediction accuracy can be improved by considering the actual vulcanization and considering the temperature change. In this case, the temperature operating conditions are determined for each vulcanizer and vulcanization specification. Therefore, these temperature conditions can be compiled into a library, quoted as necessary, and applied to the calculation. preferable.

  Moreover, in Example 1, exact | strict calculation is performed on the assumption that the temperature of a vulcanization mold is constant. However, the protrusions of the vulcanization mold that bite into the rubber are not isothermal in actual vulcanization because the heat is taken away by the rubber. When the tire groove width is large (thick protrusions are thick), the temperature error of the vulcanization mold obtained by rigorous calculation is small, and when the groove width is small, the temperature error is large. The temperature difference also depends on the block width, groove depth, vulcanization mold projection material, and other conditions. If exact calculation is performed in consideration of the cause of the temperature error on the vulcanization mold side relating to such heat conduction, a more accurate functional relationship (thickness reduction) can be grasped. In addition to the calculation, an experiment relating to heat transfer may be performed using a model vulcanization mold, and the functional relationship may be corrected based on the experimental result.

  In addition, the vulcanization mold is a metal, and its thermal conductivity is about several orders of magnitude higher than that of the rubber to be vulcanized. Therefore, when the temperature of the vulcanization mold is obtained by exact calculation, it is often the case. The temperature error of the vulcanization mold is small. However, in recent years, there is a case where a metal plate having a thickness of about 1 mm to 2 mm, called a sipe, is used by fitting it to a vulcanization mold. At this time, particularly when the fitting portion is contaminated, the resistance to heat conduction is large, and the temperature error of the vulcanization mold in the exact calculation may be increased. Even in such a case, the prediction accuracy of the blow point can be improved by correcting the functional relationship (thickening rate) by calculation or actual measurement.

  Next, a series of processing procedures in the method for predicting the equivalent vulcanization degree according to the first embodiment will be described. FIG. 8 is a flowchart illustrating a series of processing procedures in the method for predicting the equivalent vulcanization degree according to the first embodiment. In the tire, the latest vulcanization point exists in the center of the portion where the groove is shallow and the block width is wide. Therefore, candidate locations (latest vulcanization portions) where the slowest vulcanization point of the tire exists are narrowed down, and the BP may be obtained by approximating one-dimensional heat conduction / vulcanization reactivity analysis for the relevant locations.

  In executing the equivalent vulcanization degree prediction method according to the first embodiment, first, the slowest vulcanization portion is selected (step S101). Specifically, attention is focused on the block having the largest outer dimension among the blocks in the CC (Center Crown) portion and the shoulder portion Sh of the tire. In addition, since heat transfer to the inside of the tire 1 becomes difficult when w / t is large, a portion satisfying at least one of the block 3 having a large width w or a groove having a small groove depth t is selected.

9A and 9B are explanatory diagrams illustrating an example of a block group formed on the tread surface of the tire. Moreover, FIG. 9-3 is explanatory drawing about conversion to the rectangle equivalent to heat conduction. FIG. 9-4 is a plan view showing the converted rectangle. As shown in Figure 9-1, in the block 3 ₁ to 3 _3, since the groove depth t ₁ of block 3 ₁ is the smallest, in the block 3 ₁ to 3 _3, block 3 ₁ portions outermost It becomes the slow vulcanization part. Also, as shown in FIG. 9B, among the blocks 3 _{1 to} 3 ₃ , the block 3 ₁ has the maximum width. Thus, among the block 3 ₁ to 3 _3, block 3 ₁ part becomes the most retarded pressurized硫部min. Based on these criteria, the candidate for the latest vulcanization part is selected.

Next, a polygon having a constant groove depth is extracted (step S102). Specifically, when viewed from the tread surface 5 side of the tire 1, extracts the planar shape of the block 3 ₁ as the slowest pressurized硫部content candidate. Thus the planar shape of the block 3 ₁ and extracted becomes polygon. The calculated block 3 ₁ of the centroid (the center of gravity), and the width FIG sincerely twice the shortest distance to the outer periphery of the block 3 _1. Next, as illustrated in FIG. 9C, the extracted planar shape of the block 3 ₁ is converted into a thermally conductive equivalent rectangle 3 ₁ ′ (step S103). For this conversion, for example, a conversion method related to solid heat conduction disclosed in Chemical Engineering Handbook 3rd edition can be used.

After the conversion, it is determined whether the length / short ratio wl / ws (see FIG. 4) of the thermally conductive equivalent rectangle 3 ₁ ′ is 4 or more (step S104). Here, the length of the long side of the rectangle 3 ₁ ′ equivalent to heat conduction is wl, and the length of the short side is ws. These are all parameters representing the surface shape of an equivalent vulcanization degree prediction target rubber product.

If the length ratio wl / ws is 4 or more (step S104; Yes), the block 3 ₁ cross section, handled as a uniform two dimensional section (step S105), the approximation to a one-dimensional heat conduction by the procedure described above Then, heat conduction / vulcanization reactivity analysis is executed (step S106). Then, the BP at the latest vulcanization point of the tire 1 is predicted from the obtained analysis result (step S107).

When the long / short ratio wl / ws is less than 4 (step S104; No), the reduction amount of the total thickness of the tire 1 is calculated (step S108). This procedure will be described. FIG. 10 is an explanatory diagram showing an example of a procedure for thickness reduction calculation. In executing this thickness reduction calculation, first, the first thickness reduction amount ΔL1 is obtained by the above approximate expression (3), for example, with the longitudinal direction wl of the thermally conductive equivalent rectangle 3 ₁ ′ as the block width w ( Step S201). Next, based on the obtained first thickness reduction amount ΔL1, the groove depth is set to t−ΔL, which is set as a new groove depth t ′. Then, using the groove depth t ′ and the transverse direction ws of the thermally conductive equivalent rectangle 3 ₁ ′ as the block width w, the second thickness reduction amount ΔL2 is obtained by the above approximate expression (3) (step S202). ).

  By using the thickness reduction amount ΔL2 obtained in this way, even when the length / short ratio wl / ws is less than 4, it can be handled as a two-dimensional cross section having a uniform cross section (step S105). In this way, by compressing the two-dimensional section to one dimension, the heat conduction in the two-dimensional section is simplified by one-dimensional calculation, and a substantially equivalent result is obtained with respect to the latest vulcanization curve. . Furthermore, the heat conduction promoting effect from the side surface of the block can be made to correspond to the decrease in the block thickness in the form of a decrease in thickness. By paying attention to the latter, the effect of the two peak widths in the case where the block shape is regarded as a rectangle is sequentially converted into a decrease in the block thickness and added to the three-dimensional block in effect. Thus, it is possible to sequentially convert 3D to 2D and further convert 2D to 1D to reflect the effect of the 3D shape as a decrease in thickness in 1D. That is, it means that even a block having a three-dimensional shape with a non-uniform cross section can be handled as a two-dimensional cross section with a uniform cross section. It has been confirmed that the corresponding one-dimensional thickness is substantially the same regardless of which of the long side and the short side of the rectangle is dimensionally compressed first. Therefore, dimension compression may be performed first on either the long side or the short side of the rectangle.

  In addition, it can also be handled as a two-dimensional cross section with a uniform cross section by comparing with the result of the three-dimensional calculation based on a more precise conversion rule according to the length ratio and the groove depth t. After obtaining the second thickness reduction amount ΔL2, heat conduction / vulcanization reactivity analysis is performed by one-dimensional heat conduction using the second thickness reduction amount ΔL2 (step S106). And BP in the slowest vulcanization part of a tire is predicted from the obtained analysis result (Step S107).

  As described above, according to the method for predicting the equivalent vulcanization degree according to the first embodiment, by using the approximate function of the surface shape parameter and the thickness reduction parameter, the one-dimensional heat conduction / vulcanization reaction is obtained even in the two-dimensional shape. It can be analyzed by degree analysis. As a result, setting of boundary conditions and creation of an analysis model are facilitated, so that handling in analysis can be facilitated. In addition, since the amount of calculation can be suppressed by analysis in one dimension, the time until obtaining the prediction result can be shortened.

  The method for predicting the equivalent vulcanization degree according to the second embodiment is substantially the same as that of the first embodiment. However, when the total thickness in the meridional section of the tire is uneven, the latest addition in the section is performed. The difference is that it includes a procedure for estimating the sulfur content. Since other configurations are the same as those of the first embodiment, description thereof is omitted. FIG. 11 is a flowchart illustrating a series of processing procedures in the method for predicting the equivalent vulcanization degree according to the second embodiment.

  For example, when the total thickness in the meridional cross section of the tire 1 changes as in the shoulder portion Sh (FIG. 1), the slowest vulcanization portion that is considered to have the slowest vulcanization point in the cross section is determined. . First, it is determined whether or not the total thickness in the meridional section of the tire 1 is equal (step S301). If equal (step S301; Yes), the one-dimensional thickness of the tire 1 is determined (step S302), and this is set as the total thickness L of the tire 1. Next, the presence / absence of a tread pattern is determined (step S303). When the tread pattern does not exist (step S303; No), the groove 2 does not exist on the tread surface 5, so that the total thickness L of the tire 1 is used as it is, and the heat conduction / heating of the one-dimensional heat conduction is performed. A sulfur reactivity analysis is executed (step S309). Based on the analysis result, the BP at the latest vulcanization point is predicted (step S310).

  When the tread pattern exists (step S303; Yes), the BP at the latest vulcanization point is predicted by the same procedure as step S101 to step S108 described in the first embodiment (step S304 to step S313). When the total thickness in the meridional section of the tire 1 is not uniform (step S301; No), the latest vulcanization position in the section is estimated (step S311). This method will be described.

  FIG. 12 is a simplified cross-sectional view simply representing a state in which the meridian cross-sectional thickness is non-uniform. The dashed-dotted line in FIG. 12 shows the direction of heat flow. As shown in FIG. 12, the shoulder portion Sh of the tire 1 has a greater total thickness in the meridional plane cross section than the CC portion. For this reason, in the meridional section of the tire 1, it is considered that the latest vulcanized portion Asl is present in the shoulder portion Sh. It is considered that the latest vulcanization point Psl exists in the latest vulcanization portion Asl.

  Based on these assumptions, the heat flow through the latest vulcanized portion Asl is adjusted by using the simplified sectional view of the meridional section of the tire as shown in FIG. Draw a line. This drawing will be described. When the thickness of the cross section is non-uniform, an equivalent thickness is obtained on the basis that the latest vulcanization curves corresponding to the cross-sectional shape substantially coincide. This procedure can use, for example, a graphical method similar to Huygens's principle that explains the refraction of light, but organizes the calculation results by the finite element method etc. and converts the functional relationship to a one-dimensional equivalent thickness (conversion Rules).

  If heat conduction is assumed to be a heat wave (thermal wave) that travels at a constant speed from the heat source, a heat wave travels equally from the planar heat source in the depth direction. Assuming that the heat source temperatures are all equal, the portion where the heat waves from the upper and lower heat sources collide is the farthest from the heat source and is considered to be the slowest vulcanization portion. When heat waves overlap each other, they interfere with each other, and the temperature rise at that portion changes the traveling direction of the overlapping heat waves and increases the traveling speed of the heat waves. Further, when the heat wave is transmitted in a convex or concave manner, the traveling speed of the heat wave is reduced or increased corresponding to the expansion or contraction of the tip of the heat wave. And the rule which makes the breadth (cross-sectional area) by progress of a heat wave constant can be applied to drawing.

  FIG. 12 is constructed in accordance with the rules for making the spread due to the progression of the heat wave constant as described above. In FIG. 12, in the vicinity of the CC portion where the tire inner surface 4 and the tread surface 5 are parallel, the heat wave from the tire inner surface 4 and the heat wave from the tread surface 5 collide at the third wave. On the other hand, in the shoulder portion Sh, the heat wave from the tire inner surface 4 and the heat wave from the tread surface 5 collide at the approximately 4.5th wave. That is, the heat from the heat source in the tire inner surface 4 and the heat source in the tread surface 5 has reached this portion.

  Thereby, the thickness of the tread surface 5 and the tire inner surface 4 corresponding to the latest vulcanized portion Asl and the latest vulcanized portion Asl can be estimated. That is, the portion where the heat wave finally collided corresponds to the estimated slowest vulcanization portion Asl. In this example, 1.5 times the thickness in the vicinity of the CC portion of the tire (4.5 / 3 = 1.5) is the thickness (equivalent thickness) corresponding to the latest vulcanized portion Asl. . The above technique is one of the techniques for making the unequal thickness portion expressed in two dimensions one-dimensional (dimensional compression). Further, the influence of the rectangular dimension of the block pattern and the groove depth may be made one-dimensional by the procedure described (Example 1).

  The estimated thickness of the tread surface 5 and the tire inner surface 4 corresponding to the latest vulcanized portion Asl is the longest heat flow line (Ln in FIG. 12). And, it is considered that the slowest vulcanization point Psl in the meridional section is present on the longest heat flow line Ln. Accordingly, it is determined that the heat flow line passes through the latest vulcanization point Psl (step S312), and the heat conduction distance passing through the latest vulcanization point is determined as Ln. The heat conduction distance passing through the latest vulcanization point can also be obtained by two-dimensional or three-dimensional heat conduction / vulcanization reactivity analysis. The heat conduction distance passing through the latest vulcanization point thus determined is determined as the one-dimensional thickness of the tire 1 when the total thickness in the meridional section is not uniform (step S302). The total thickness L of the tire 1 is assumed. Since the subsequent processing procedure is as described above, the description thereof is omitted (steps S303 to S313).

  The equivalent vulcanization degree prediction method according to the first and second embodiments can be realized by executing a computer program prepared in advance on a computer such as a personal computer or a workstation. This computer program can be distributed via a network such as the Internet. The computer program can also be executed by being recorded on a computer-readable recording medium such as a hard disk, a flexible disk (FD), a CD-ROM, an MO, and a DVD and being read from the recording medium by the computer.

  As described above, the method for predicting the equivalent vulcanization degree according to the second embodiment includes the procedure for estimating the latest vulcanization portion in the meridional section of the tire, and thus the total thickness of the tire in the section is not uniform. In addition, the latest vulcanization portion can be predicted, and the equivalent vulcanization degree can be predicted with higher accuracy.

  In Example 3, a rubber product manufacturing method including the method for predicting the equivalent vulcanization degree according to Example 1 or 2 will be described. FIG. 13 is a flowchart for explaining the procedure of the rubber product manufacturing method according to the third embodiment. In the third embodiment, a tire is described as an example of a rubber product, but it goes without saying that this rubber product manufacturing method can be applied to a conveyor belt and a fender. First, vulcanization conditions for a tire to be vulcanized are acquired (S401). Vulcanization conditions include, for example, vulcanization temperature and pressure conditions determined according to the type of rubber, the type of additive, the size of the tire, and the like.

  Next, the heating-related conditions are acquired from the vulcanization conditions, and the block width w, groove depth t, total tire thickness L, and other geometric conditions determined by the type of tire are acquired. Then, the BP in the latest vulcanization portion of the tire to be vulcanized is predicted by the equivalent vulcanization degree prediction method according to Example 1 or 2 (step S402). Thereafter, the green tire is placed in a vulcanization mold (step S403), and vulcanization is started (step S404).

  Vulcanization is started, and when the BP predicted in step S402 is reached, vulcanization is terminated (step S405) and demolded (step S406). As described above, in the tire manufacturing method according to Example 3, the BP in the latest vulcanized portion of the tire is predicted by the equivalent vulcanization degree prediction method according to Example 1 or 2, and vulcanized with the predicted BP. Exit. Thereby, since it can be simply and quickly predicted with practically sufficient accuracy, the BP can be efficiently obtained even in a manufacturing situation in which BPs of various types of tires must be managed. As a result, the mold can be removed at the optimum timing, so that the tire manufacturing efficiency is improved and the yield is also improved.

As described above, the manufacturing method of the prediction method及Beauty rubber products equivalent vulcanization degree according to the present invention is useful for vulcanization of rubber products, particularly suitable for the prediction of equivalent degree of vulcanization.

It is a fragmentary sectional view which shows a partial cross section containing the meridian surface of the tire which is an example of a rubber product. It is the partial sectional view which expanded a part of tread surface of a tire. It is explanatory drawing which shows the change with respect to time of an equivalent vulcanization | cure degree. It is explanatory drawing of the slowest vulcanization point of a tire. It is explanatory drawing which shows the 1st latest vulcanization curve calculated strictly by two-dimensional heat conduction and vulcanization reactivity analysis. It is an example of the analysis model used for two-dimensional heat conduction and vulcanization reactivity analysis. It is explanatory drawing which shows the 2nd latest vulcanization curve analyzed by the one-dimensional heat conduction and vulcanization reactivity analysis. It is an example of the analysis model used for the one-dimensional heat conduction and vulcanization reactivity analysis. It is explanatory drawing which shows the state which piled up the 1st and 2nd slowest vulcanization curves analyzed by the two-dimensional and one-dimensional heat conduction and vulcanization reactivity analysis. It is explanatory drawing which represented the relationship between the thickness reduction parameter and w / t by logarithmically displaying a horizontal axis. 3 is a flowchart showing a series of processing procedures in a method for predicting an equivalent vulcanization degree according to Embodiment 1. It is explanatory drawing which shows an example of the block group formed in the tread surface of a tire. It is explanatory drawing which shows an example of the block group formed in the tread surface of a tire. It is explanatory drawing about conversion to the rectangle equivalent in heat conduction. It is a top view which shows the rectangle after conversion. It is explanatory drawing which shows an example of the procedure of thickness reduction calculation. 6 is a flowchart showing a series of processing procedures in a method for predicting an equivalent vulcanization degree according to a second embodiment. It is a simple sectional view which expressed simply the state where the thickness of the meridional section is not uniform. It is a flowchart explaining the procedure of the manufacturing method of the rubber product which concerns on Example 3. FIG.

Explanation of symbols

1 tire 2 groove 2u bottom 3, 3 ₁ block 3t top 4 tire inner surface 5 tread surface

Claims (4)

Computer
A cross section including the latest vulcanization portion of the rubber product by two-dimensional heat conduction / vulcanization reactivity analysis by changing the block width w and the groove depth t, which are parameters representing the shape of the cross section of the surface shape of the rubber product. A plurality of first slowest vulcanization curves corresponding to different values of the parameters w and t in the interior, and corresponding to different values of parameters representing the dimension / thickness L of the section in the direction of heat flow in the section Then , a procedure for obtaining a plurality of second slowest vulcanization curves in the cross section by one-dimensional heat conduction / vulcanization reactivity analysis,
From the correspondence relationship between the plurality of second slowest vulcanization curve and the plurality of first slowest vulcanization curve, before representing Kipa parameters w, and t, the decrease ΔL of dimensions and thickness L of the cross section A procedure for obtaining an approximate function with the thickness reduction parameter ΔL / t ;
Equivalent vulcanization degree prediction target rubber products before Kipa parameter w, the value of the reduced thickness parameter [Delta] L / t corresponding to the value of t obtained from the approximate function, using the value of the reduced thickness parameter [Delta] L / t obtained Thus, by performing a one-dimensional heat conduction / vulcanization reactivity analysis in a cross section including the slowest vulcanization part of the rubber product subject to the equivalent vulcanization degree prediction, the equivalent vulcanization in the slowest vulcanization part of the rubber product is performed. A procedure for predicting the degree of sulfur;
A method for predicting an equivalent vulcanization degree, characterized in that a computer program describing the above is executed. Extract the planar shape of the block surrounded by the groove with the groove depth t on the surface of the equivalent vulcanization degree prediction target rubber product , convert it into a heat conductive equivalent rectangle, and the length wl of its long side The short side length ws is used as a parameter representing the surface shape, and one of the long side length wl and the short side length ws is used as a block width, and the corresponding first thickness reduction amount ΔL1 is the approximate function. From
Next, the groove depth is set to t−ΔL1 and the value of the corresponding second thickness reduction amount ΔL2 is determined from the approximate function using the other of the long side length wl and the short side length ws as the block width. By performing a one-dimensional heat conduction / vulcanization reactivity analysis in a cross section including the slowest vulcanization portion of the equivalent vulcanization degree prediction target rubber product using the value of the second thickness reduction amount ΔL2 , the rubber The method for predicting the equivalent vulcanization degree according to claim 1, wherein the equivalent vulcanization degree in the latest vulcanization part of the product is predicted. The planar shape of the surface block of the rubber product to be predicted for equivalent vulcanization degree is extracted, converted into a heat conductive equivalent rectangle, and the long side length wl and the short side length ws are converted into the surface shape. And a long / short ratio wl / ws,
When the long / short ratio wl / ws is equal to or less than a predetermined value, the value of the first thickness reduction amount ΔL1 corresponding to one of the long side length wl and the short side length ws as a block width is approximated. Next, the groove depth is t-ΔL1, the long side length wl, the other of the short side lengths ws is the block width, and the corresponding second thickness reduction amount ΔL2 is obtained from the approximate function. Then, using the obtained value of the second thickness reduction ΔL2, to perform a one-dimensional heat conduction and vulcanization reactivity analysis in the cross section including the slowest vulcanization portion of the equivalent vulcanization degree prediction target rubber product,
When the long / short ratio wl / ws is equal to or greater than a predetermined value and the cross section including the slowest vulcanized portion of the equivalent vulcanization degree prediction target rubber product can be handled as a uniform two-dimensional shape, the long side length wl Without obtaining the value of the thickness reduction parameter corresponding to the above , the value of the thickness reduction parameter ΔL / t corresponding to the short side length ws as the block width is obtained from the approximate function, and the obtained thickness reduction parameter ΔL / Using the value of t, by performing a one-dimensional heat conduction / vulcanization reactivity analysis in the cross section including the slowest vulcanization portion of the rubber product subject to prediction of the equivalent vulcanization degree, the slowest vulcanization of the rubber product is performed. The equivalent vulcanization degree prediction method according to claim 1, wherein the equivalent vulcanization degree in the sulfur portion is predicted. The equivalent vulcanization degree of the rubber product to be vulcanized is predicted by the equivalent vulcanization degree prediction method according to any one of claims 1 to 3, and the rubber product to be vulcanized is blown from the predicted equivalent vulcanization degree. Steps to predict points,
The procedure to start vulcanization in a vulcanization mold,
Finishing vulcanization at the predicted blow point and demolding,
A method for producing a rubber product, comprising:

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