JP7684566B2 - Method and device for estimating flow characteristics of rubber, and method for simulating flow of unvulcanized rubber - Google Patents

Description

The present invention relates to a method and device for estimating the flow characteristics of rubber, and a method for simulating the flow of unvulcanized rubber. More specifically, the present invention relates to a method and device for estimating the flow characteristics of rubber during vulcanization with greater accuracy, and a method for simulating the flow of unvulcanized rubber.

When manufacturing rubber products such as tires, a molded body made from unvulcanized rubber is vulcanized in a mold. Alternatively, rubber products can be manufactured by injecting unvulcanized rubber into a mold. The unvulcanized rubber flows inside the mold, and is shaped into the desired shape by the mold. If the unvulcanized rubber does not flow sufficiently, it may not be possible to shape it into the desired shape, which will have a significant impact on the quality of the rubber product. This flow characteristic also affects the vulcanization time, i.e., the productivity of rubber products.

The behavior of unvulcanized rubber during vulcanization is therefore simulated. For this simulation, index data showing the flow characteristics of rubber is required, and viscosity is used as a representative index data. The viscosity elements of rubber can be broadly divided into basic viscosity elements that are affected by shear rate and temperature, and thermosetting elements that are affected by thermal history (vulcanization temperature and vulcanization time). A capillary rheometer is a commonly known method for understanding basic viscosity elements. A flat-plate rotational viscometer (curastometer) is a commonly known method for understanding thermosetting elements.

When the basic viscosity element and the thermosetting element obtained by the above method are used in combination to calculate the overall viscosity and use it to simulate the behavior of vulcanized rubber, it is difficult to achieve a high enough consistency between the actual behavior of unvulcanized rubber and the simulation results. This is because the basic viscosity element and the thermosetting element are obtained by different methods (different devices), and variations (inconsistencies) occur due to the differences between the methods.

As a method for measuring the viscosity of unvulcanized rubber, a method has been proposed in which unvulcanized rubber is filled into a flow path of a certain cross-sectional shape, and the viscosity is calculated based on the detected pressure and detected flow rate in the flow path, or based on the detected pressure and the tip position and detected speed of the unvulcanized rubber (see Patent Document 1). However, this method does not grasp the basic viscosity element and the thermosetting element of the unvulcanized rubber separately. Therefore, there is room for improvement in estimating the flow characteristics of unvulcanized rubber during vulcanization with greater accuracy.

JP 2019-27959 A

The object of the present invention is to provide a method and device that can estimate the flow characteristics of rubber during vulcanization with greater accuracy, as well as a method for simulating the flow of unvulcanized rubber.

In order to achieve the above object, the rubber flow characteristic estimation method of the present invention is a rubber flow characteristic estimation method that estimates the basic viscosity element and thermosetting element of the viscosity during vulcanization of a target rubber in which a vulcanizing agent is blended with unvulcanized rubber, and is characterized in that while adjusting the heating condition for the flow path, the target rubber is caused to flow in the flow path by a flow means in a state before the start of vulcanization hardening and in a state after the start of vulcanization hardening, the basic viscosity element is estimated based on the movement speed of the flow means that causes the target rubber to flow in the state before the start of vulcanization hardening under constant temperature conditions and the pressure that the flow means receives from the target rubber, and the thermosetting element is estimated based on the change in pressure that the flow means that causes the target rubber to flow in the state after the start of vulcanization hardening under constant temperature conditions and constant movement speed conditions receives from the target rubber.

Another rubber flow characteristic estimation method of the present invention is a rubber flow characteristic estimation method that estimates the basic viscosity element and thermosetting element of the viscosity during vulcanization of a target rubber in which a vulcanizing agent is blended with unvulcanized rubber, and is characterized in that the target rubber and a comparison rubber that is blended from the target rubber without the vulcanizing agent and prepared to have the same viscosity are prepared, the target rubber and the comparison rubber are each individually flowed by a flow means in the same flow path while adjusting the heating condition for the flow path, the basic viscosity element is estimated based on the movement speed of the flow means that flows the comparison rubber or the target rubber in a state before the start of vulcanization hardening under constant temperature conditions and the pressure that the flow means receives from the flowing rubber, and the thermosetting element is estimated based on the pressure that the flow means that flows the comparison rubber receives from the comparison rubber and the pressure that the flow means that flows the target rubber in a state after the start of vulcanization hardening receives from the target rubber under constant temperature conditions and constant movement speed conditions.

The rubber flow characteristic estimation device of the present invention is a rubber flow characteristic estimation device that estimates the basic viscosity element and thermosetting element of the viscosity during vulcanization of a target rubber in which a vulcanizing agent is blended with unvulcanized rubber, and has a flow path, a heating means for adjusting the heating condition for the flow path, a flow means for flowing the target rubber in the flow path in a state before the start of vulcanization hardening and in a state after the start of vulcanization hardening, and a calculation unit, and is characterized in that the basic viscosity element is estimated by the calculation unit based on the movement speed of the flow means that flows the target rubber in a state before the start of vulcanization hardening under constant temperature conditions and the pressure that the flow means receives from the target rubber, and the thermosetting element is estimated by the calculation unit based on the change in pressure that the flow means that flows the target rubber in a state after the start of vulcanization hardening receives from the target rubber under constant temperature conditions and constant movement speed conditions.

Another rubber flow characteristic estimation device of the present invention is a rubber flow characteristic estimation device that estimates the basic viscosity element and thermosetting element of the viscosity during vulcanization of a target rubber in which a vulcanizing agent is blended with unvulcanized rubber, and has a flow path, a heating means for adjusting the heating condition for the flow path, a flow means for flowing the target rubber in the flow path in a state before the start of vulcanization hardening and in a state after the start of vulcanization hardening, and a calculation unit, and the target rubber and a comparison rubber prepared to have the same viscosity by blending the target rubber without the vulcanizing agent are each individually flowed through the same flow path by the flow means while adjusting the heating condition for the flow path. The calculation unit estimates the basic viscosity element based on the movement speed of the flow means that flows the comparative rubber or the target rubber in a state before the start of vulcanization hardening under constant temperature conditions and the pressure that the flow means receives from the flowing rubber, and the calculation unit estimates the thermosetting element based on the pressure that the flow means that flows the comparative rubber receives from the comparative rubber and the pressure that the flow means that flows the target rubber in a state after the start of vulcanization hardening receives from the target rubber under constant temperature conditions and constant movement speed conditions.

The unvulcanized rubber flow simulation method of the present invention is characterized in that the basic viscosity element and the thermosetting element estimated by the above-mentioned rubber flow property estimation method are used as the basic viscosity element and the thermosetting element of viscosity when performing a flow simulation of the target rubber, respectively.

According to the former rubber flow characteristic estimation method and device of the present invention, the shear rate dependency of viscosity of the target rubber as the basic viscosity element can be grasped based on the moving speed of the flow means that causes the target rubber to flow in the flow path in a state before the start of vulcanization hardening under constant temperature conditions, and the pressure that the flow means receives from the target rubber. In addition, the thermal history dependency of viscosity of the target rubber as the thermosetting element can be grasped based on the change in pressure that the flow means that causes the target rubber to flow in the flow path in a state after the start of vulcanization hardening receives from the target rubber under constant temperature conditions and constant moving speed conditions.

According to the latter rubber flow characteristic estimation method and device of the present invention, the target rubber and the comparative rubber are each individually flowed through the same flow path by a flow means while adjusting the heating condition for the flow path, and the shear rate dependency of the viscosity of the target rubber as the basic viscosity element can be grasped based on the movement speed of the flow means that flows the comparative rubber or the target rubber in a state before the start of vulcanization hardening under constant temperature conditions and the pressure that the flow means receives from the flowing rubber. In addition, the thermal history dependency of the viscosity of the target rubber as the thermosetting element can be grasped based on the pressure that the flow means that flows the comparative rubber receives from the comparative rubber and the pressure that the flow means that flows the target rubber in a state after the start of vulcanization hardening receives from the target rubber under constant temperature conditions and constant movement speed conditions.

In this way, according to the present invention, the basic viscosity element and the thermosetting element of the viscosity of the target rubber can be grasped by one method using the same device. Therefore, it is advantageous to prevent the problem that the calculation results vary (become inconsistent) due to the difference in the method (device) for grasping each element, as in the case where the basic viscosity element and the thermosetting element are grasped by different methods (devices). Therefore, by grasping the basic viscosity element and the thermosetting element by the present invention, it is possible to estimate the flow characteristics of the target rubber during vulcanization with higher accuracy. Therefore, according to the flow simulation method of unvulcanized rubber of the present invention, it is possible to make the behavior of the target rubber flowed in the simulation model more approximate to the behavior of the target rubber in the actual manufacturing process.

1 is an explanatory diagram illustrating a longitudinal sectional view of a rubber flow characteristic estimating device according to the present invention. FIG. 2 is a graph illustrating the change over time in the piston movement speed and the pressure that the piston receives from the target rubber in the process of vulcanization of the target rubber in FIG. 1 . FIG. 2 is a graph illustrating the relationship between the moving speed of the piston and the pressure that the piston receives from the target rubber of FIG. 1 before the target rubber starts to be vulcanized and hardened. FIG. FIG. 2 is a graph illustrating the relationship between the shear rate and viscosity of a target rubber before the start of vulcanization hardening. FIG. 4 is a graph illustrating the change in viscosity of a target rubber over time. FIG. 2 is a graph illustrating the change over time in the viscosity increase rate of a target rubber. FIG. 2 is a graph illustrating the change over time in viscosity of a comparative rubber and a target rubber. FIG. 11 is a graph illustrating the change over time in the tip position of a target rubber in a simulation. FIG. 2 is an explanatory diagram illustrating a vertical cross-sectional view of another embodiment of a rubber flow characteristic estimation device. FIG. 10 is an explanatory diagram illustrating the rubber flow characteristic estimation device of FIG. 9 in a plan view.

The rubber flow property estimation method and device, as well as the unvulcanized rubber flow simulation method of the present invention, are described below based on the embodiments shown in the figures.

The present invention estimates the flow characteristics of target rubber R1, which is unvulcanized rubber mixed with a vulcanizing agent, during the vulcanization process. In order to estimate the viscosity (shear viscosity) of target rubber R1, which is an index showing the flow characteristics, with greater accuracy, this viscosity is understood by distinguishing it into the basic viscosity element MA (shear rate dependency) and thermosetting element MB (thermal history dependency) described above. This viscosity can be expressed as the basic viscosity element MA x thermosetting element MB.

In the present invention, target rubber R1 and unvulcanized rubber R2 (hereinafter referred to as comparative rubber R2) that is compounded by excluding the vulcanizing agent from target rubber R1 may be used. Hereinafter, target rubber R1 and comparative rubber R2 will be collectively referred to as rubber R. First, an embodiment in which only target rubber R1 is used and comparative rubber R2 is not used will be described. Target rubber R1 is manufactured by compounding various compounding agents, including a vulcanizing agent, with raw rubber and kneading them.

The unvulcanized rubber flow characteristic estimation device 1 (hereinafter referred to as the estimation device 1) of the present invention shown in FIG. 1 has a flow path 4, a heating means 4a, a flow means 5 for causing the rubber R to flow through the flow path 4, and a calculation unit 8. The estimation device 1 further has a cylinder 2a that serves as a storage unit for the rubber R, a temperature sensor 6, and a control unit 7. The flow path 4 is formed in a die 3 fixed to the tip of the cylinder 2a, and the flow path 4 and the inside of the cylinder 2a are connected to each other. A computer is used as the control unit 7 and the calculation unit 8. In this embodiment, one computer is used as the control unit 7 and the calculation unit 8, but each may be separate.

The flow path 4 is not limited to being formed in the die 3, but may be, for example, a tube. The cross-sectional shape of the flow path 4 may be a polygon such as a circle, ellipse, triangle, square, or pentagon, but a circular cross section, which is generally used in actual manufacturing processes, is preferable. This flow path 4 has a constant cross-sectional shape, and its cross-sectional area is substantially constant over its entire length and extends straight. The flow path 4 may extend in a curved manner, but it is preferable that it is linear.

The heating means 4a heats the flow path 4 and can adjust the degree of heating for the flow path 4. For example, an electric heater that covers the outside of the flow path 4 is used as the heating means 4a. The heating means 4a heats the flow path 4 to a predetermined temperature that promotes the crosslinking reaction of the target rubber R1, and this predetermined temperature is, for example, any temperature between 100°C and 250°C. The degree of heating by the heating means 4a is controlled by the control unit 7.

The flow means 5 causes the rubber R to flow while it is filled in the flow path 4. In this embodiment, the flow means 5 has a piston 5a arranged inside the cylindrical cylinder 2a, and a drive mechanism 5c that moves the piston 5a in the axial direction. For example, a drive motor is used as the drive mechanism 5c. The inner circumferential surface of the cylinder 2a, which has a constant inner diameter, and the outer circumferential surface of the piston 5a, which has a constant outer diameter, face each other with almost no gap between them. The flow means 5 is controlled by the control unit 7.

The temperature sensor 6 detects the temperature of the die 3 (flow path 4) at its installation position. The data detected by the temperature sensor 6 is input to the calculation unit 8.

The calculation unit 8 compares the detection data (detected temperature) from the temperature sensor 6 with a preset target temperature and transmits the comparison result to the control unit 7. The control unit 7 controls the heating level by the heating means 4a so that the difference between the detected temperature and the target temperature is eliminated.

The calculation unit 8 receives input of the axial movement speed S of the piston 5a that is causing the rubber R to flow, and the axial pressure P that the piston 5a receives from the flowing rubber R. This movement speed S can be grasped by the control unit 7. This pressure P can be calculated using the axial pressing force F of the piston 5a against the rubber R, which can be grasped based on the magnitude of the output (motor output, etc.) of the drive mechanism 5c, or it can be detected by providing a pressure sensor.

In addition to the various data described above, known data such as the cross-sectional area of the piston 5a (the inner cross-sectional area of the cylinder 2a), the cross-sectional area of the flow path 4, and the length of the flow path 4 are input to the calculation unit 8. The calculation unit 8 performs various calculation processes using the input data.

The vulcanization hardening of the target rubber R1 is accelerated by heating it. Therefore, when the flow path 4 is heated and the target rubber R1 is caused to flow through the flow path 4 under constant temperature conditions with the movement speed S of the piston 5a being constant, as shown in the example of Figure 2, the pressure P that the piston 5a receives from the flowing target rubber R1 suddenly decreases and increases midway.

More specifically, as shown in FIG. 2, before the elapsed time from when the target rubber R1 is caused to flow in the flow path 4 exceeds tx, the pressure P is relatively small and generally constant, and after tx is exceeded, the pressure P increases rapidly. In other words, before the elapsed time tx, the target rubber R1 is in a state before the start of vulcanization hardening, so its fluidity is relatively high, and after that, the target rubber R1 is in a state after the start of vulcanization hardening, so its fluidity decreases. The present invention utilizes the characteristics of the target rubber R1 in FIG. 2.

Next, we will explain the procedure for determining the basic viscosity element MA and thermosetting element MB of the target rubber R1.

To determine the basic viscosity element MA, the target rubber R1 is caused to flow in the flow path 4 in a state before the start of vulcanization hardening. The basic viscosity element MA is estimated by calculation processing by the calculation unit 8 based on the movement speed S of the piston 5a that is causing the target rubber R1 to flow in a state before the start of vulcanization hardening under constant temperature conditions and the pressure P that the piston 5a receives from the target rubber R1.

As shown in FIG. 1, the target rubber R1 is placed in the cylinder 2a, and the temperature of the flow path 4 may be room temperature. Next, the piston 5a is moved forward in the axial direction to press the target rubber R1, and the target rubber R1 is injected from the cylinder 2a into the flow path 4. The target rubber R1 flows uninterruptedly in the cylinder 2a and the flow path 4, filling the flow path 4. Here, as shown in FIG. 3, the constant moving speed S is changed to several different speeds, and the pressure P at each moving speed S is measured.

When the calculation unit 8 calculates the viscosity η of the rubber R, the following equations (1), (2), and (3) are used.
Apparent shear stress τ = (P d) / 4L (1)
Apparent shear rate γ=4Q/(π·(d ³ /8)) (2)
Viscosity η (apparent shear viscosity) = τ / γ (3)
Here, P = 4F/π・^D2 , Q = ^πD2 /4(S/60), P is the internal pressure of the cylinder 2a (Pa), F is the pressing force (N) of the piston 5a in the axial direction against the rubber R, D is the inner diameter of the cylinder 2a (mm), d is the inner diameter of the flow path 4 (mm), L is the length of the flow path 4 (mm), Q is the volumetric flow rate ratio ( ^mm3 /sec), and S is the moving speed of the piston 5a in the axial direction (mm/min).
Incidentally, the formulas (1) to (3) are calculation formulas applied to a circular pipe flow passage, but when the cross-sectional shapes of the flow passage 4 and the cylinder 2a are other than circular, the formulas (1) to (3) are used with some modifications.

The calculation unit 8 calculates the shear rate γ and viscosity η using the pressure P measured at each moving speed S and the above-mentioned formulas (1), (2), and (3). The calculated shear rate γ and viscosity η are plotted on the graph shown in FIG. 4 to obtain data D1. This data D1 indicates the shear rate dependency of viscosity η, and therefore becomes the basic viscosity element MA. The data D1 shown in FIG. 4 changes depending on the temperature of the target rubber R1, so it is advisable to obtain it by varying the temperature of the flow path 4 (target rubber R1) to multiple values.

To grasp the thermosetting element MB, the target rubber R1 is caused to flow in the flow path 4 in a state after the start of vulcanization hardening. Then, under conditions of constant temperature and constant movement speed S of the piston 5a, the thermosetting element MB is estimated by calculation processing by the calculation unit 8 based on the change in pressure P that the piston 5a, which is causing the target rubber R1 to flow, receives from the target rubber R1.

As shown in FIG. 1, the target rubber R1 is placed in the cylinder 2a, and the flow path 4 is heated to a predetermined temperature by the heating means 4a. Next, the piston 5a is moved forward in the axial direction to press the target rubber R1, and the target rubber R1 is injected from the cylinder 2a into the flow path 4. The target rubber R1 flows uninterruptedly through the cylinder 2a and the flow path 4, filling the flow path 4. Here, the pressure P( is measured over time while maintaining a constant moving speed S (the change in pressure P over time is measured). This allows the pressure P to be measured after the elapsed time exceeds tx, as shown in FIG. 2.

By using the measured pressure P at a predetermined constant moving speed S and the above-mentioned formulas (1), (2), and (3), the calculation unit 8 calculates the viscosity η over time as shown in FIG. 5 (the change in viscosity η over time is calculated).

Data D2 is obtained by plotting the viscosity η of the data in Figure 5, with the viscosity η at the start of vulcanization hardening (tx) of the target rubber R1 as a reference of 1. Figure 5 is written with the vertical axis representing the viscosity increase ratio to the viscosity η at the start of vulcanization hardening (tx). This data D2 shows the thermal history dependency of viscosity η, and is therefore the basic viscosity element MB. Before the start of vulcanization hardening of the target rubber R1, there is no change in viscosity η due to thermal history, so data D2 is constant at the reference value of 1 before the elapsed time tx. Note that since the viscosity increase ratio does not change even if the movement speed S of the piston 5a is changed, the movement speed S can be any one condition.

The process of determining the basic viscosity element MA and the process of determining the thermosetting element MB can be performed consecutively or separately. When both processes are performed consecutively, the target rubber R1 is caused to flow by the flow means 5 in a state before the start of vulcanization curing in the flow path 4 heated to a predetermined temperature by the heating means 4a, and then the target rubber R1 is continued to be caused to flow by the flow means 5 in a state after the start of vulcanization curing in the flow path 4, so that both processes can be performed in a short time. However, since the target rubber R1 in a state before the start of vulcanization curing changes to a state after the start of vulcanization curing midway, it is necessary to perform a measurement to determine the basic viscosity element MA quickly.

When both processes are carried out separately, the target rubber R1 is flowed in flow path 4 by flow means 5 in a state before the start of vulcanization hardening, and then another target rubber R1 is flowed in this flow path 4 by flow means 5 in a state after the start of vulcanization hardening. When both processes are carried out separately, one target rubber R1 can be reliably maintained in a state before the start of vulcanization hardening, and the other target rubber R1 can be reliably maintained in a state after the start of vulcanization hardening, which is advantageous for accurately grasping the basic viscosity element MA and the thermosetting element MB.

The time (tx) when the vulcanization hardening of the target rubber R1 begins may not be clearly indicated, as shown in FIG. 5. In such a case, for example, the minimum value of viscosity η after the target rubber R1 begins to flow through flow path 4 is set as the reference value of 1 to grasp the basic viscosity element MB.

Alternatively, by using the target rubber R1 and the comparative rubber R2, it is possible to clarify the time (tx) at which the vulcanization hardening of the target rubber R1 begins. Therefore, an embodiment using the target rubber R1 and the comparative rubber R2 will be described.

In this embodiment, as a preparatory step, a target rubber R1 and a comparative rubber R2 are prepared, each having the same predetermined viscosity at a set specified temperature. This specified temperature is a temperature at which the crosslinking reaction of the target rubber R1 is not accelerated, and may be set to, for example, about 10°C to 50°C, or room temperature.

Comparative rubber R2 is manufactured by blending and kneading various compounding ingredients, excluding only the vulcanizing agent, from the compounding of target rubber R1, to a specified viscosity. Since it is not possible to make the viscosities of target rubber R1 and comparative rubber R2 exactly the same, it is sufficient that they have equivalent viscosities. Equivalent viscosity means that the viscosity (Pa·s) of comparative rubber R2 is approximately ±1% of the viscosity (Pa·s) of target rubber R1. The viscosities of target rubber R1 and comparative rubber R2 can be confirmed using a general viscometer such as a capillary rheometer.

If the compounding ratio of the vulcanizing agent in the target rubber R1 is small and its effect on viscosity can be ignored, the comparative rubber R2 is manufactured from a compounding ratio in which only the vulcanizing agent is simply removed from the compounding ratio of the target rubber R1. If the compounding ratio of the vulcanizing agent in the target rubber R1 is relatively large and its effect on viscosity cannot be ignored, for example, the compounding amounts of the remaining compounding agents in the target rubber R1 excluding the vulcanizing agent are adjusted to compensate for the change in viscosity caused by removing the vulcanizing agent from the compounding ratio of the target rubber R1. This makes the target rubber R1 and the comparative rubber R2 have the same viscosity. The only difference between the target rubber R1 and the comparative rubber R2 is essentially the presence or absence of the vulcanizing agent.

The target rubber R1, which is a plastic body, contains a vulcanizing agent, so when heated, a cross-linking reaction occurs, causing it to harden through vulcanization and change into an elastic body. The comparison rubber R2 does not contain a vulcanizing agent, so even when heated, no cross-linking reaction occurs and it does not harden through vulcanization and remains a plastic body.

In this embodiment, the target rubber R1 and the comparative rubber R2 are each individually caused to flow in the same flow path 4 by the flow means 5 while adjusting the heating condition for the flow path 4. To grasp the thermosetting element MB, the comparative rubber R2 is caused to flow in the flow path 4, and the target rubber R1 is caused to flow in the state after the start of vulcanization hardening. Then, under constant temperature conditions and constant movement speed S of the piston 5a, the thermosetting element MB is estimated by calculation processing by the calculation unit 8 based on the pressure P that the piston 5a causing the comparative rubber R2 to flow receives from the comparative rubber R2, and the pressure P that the piston 5a causing the target rubber R1 to flow in the state after the start of vulcanization hardening receives from the target rubber R1.

As in the previous embodiment, the piston 5a is maintained at a constant moving speed S for the target rubber R1 and the comparative rubber R2, and the pressure P is measured over time (the change in pressure P over time is measured). By using the measured pressure P at the predetermined constant moving speed S and the above-mentioned equations (1), (2), and (3), the calculation unit 8 calculates data n1 and n2 as the viscosity η over time shown in FIG. 7 for each of the target rubber R1 and the comparative rubber R2 (the change in viscosity η over time is calculated).

Since the comparative rubber R2 does not harden by vulcanization even when heated, the point at which data n1 and n2 diverge in Figure 7 is the vulcanization start time (tx) of the target rubber R1. By using the target rubber R1 and the comparative rubber R2 in this way, it is possible to clearly grasp the vulcanization start time (tx) of the target rubber R1. As a result, by setting the viscosity η of the comparative rubber R2 to the reference value of 1, data D2 similar to that in Figure 6 can be obtained.

The basic viscosity element MA is the same for both the target rubber R1 and the comparative rubber R2, so either rubber R1 or R2 may be used to determine the basic viscosity element MA. Therefore, in this embodiment, to determine the basic viscosity element MA, the comparative rubber R2 or the target rubber R1 is caused to flow in the flow path 4 in a state before the start of vulcanization hardening. The basic viscosity element MA is then estimated by calculation processing by the calculation unit 8 based on the movement speed S of the piston 5a that is causing the rubber R to flow under constant temperature conditions and the pressure P that the piston 5a receives from the rubber R that is being caused to flow.

As explained in the various embodiments described above, in the present invention, the basic viscosity element MA and the thermosetting element MB of the viscosity η of the target rubber R1 can be grasped by one method using the same estimation device 1. Therefore, this is advantageous in preventing the problem of the calculation results varying (becoming inconsistent) due to differences in the methods (devices) for grasping the basic viscosity element MA and the thermosetting element MB, as in the conventional case.

As a result, by grasping the basic viscosity element MA and the thermosetting element MB according to the present invention, it becomes possible to estimate the flow characteristics of the target rubber R1 during vulcanization with higher accuracy. When simulating the behavior of the target rubber R1 during the vulcanization process, the basic viscosity element MA and the thermosetting element MB calculated above are used as index data (viscosity) indicating the flow characteristics of the target rubber R1. These basic viscosity elements MA and thermosetting element MB are applied to a simulation model, and the simulation model is caused to flow in a mold by a computer to confirm its behavior. For example, as shown in FIG. 8, data Lx indicating the tip position of the target rubber R1 flowing during vulcanization can be calculated, and the tip position can be estimated with high accuracy.

Therefore, according to the unvulcanized rubber flow simulation method of the present invention, it is possible to make the behavior of the target rubber R1 flowed in the simulation model more similar to the behavior of the target rubber R1 in the actual manufacturing process. The basic viscosity element MA and thermosetting element MB can be used to simulate the behavior of unvulcanized rubber when manufacturing various rubber products such as tires, hoses, fenders, and conveyor belts, as well as the rubber components that make up these rubber products, and rubber manufacturing equipment components such as bladders.

The estimation device 1 illustrated in Figures 9 and 10 can also be used. This estimation device 1 has a container 2b, which is a cylinder with a constant cross-sectional area. The inside of this container 2b forms a flow path 4. The flow means 5 has a rotating disk 5b that rotates around the cylindrical axis of the container 2b inside the container 2b, and a drive mechanism 5c that drives the rotation of this rotating disk 5b. Therefore, this estimation device 1 has a configuration in which the die 3 and cylinder 2a of the previous embodiment described above are replaced with the container 2b, and the piston 5a is replaced with the rotating disk 5b, and is otherwise substantially the same.

In this estimation device 1, the heating condition of the flow path 4 is adjusted by the heating means 4a, while the target rubber R1 is rotated and flowed by the rotating disk 5b in the flow path 4 in the state before the start of vulcanization hardening and in the state after the start of vulcanization hardening. The calculation unit 8 estimates the basic viscosity element MA based on the rotational movement speed S of the rotating disk 5b that rotates and flows the target rubber R1 in the state before the start of vulcanization hardening under constant temperature conditions, and the pressure P in the rotational direction that the rotating disk 5b receives from the target rubber R1. Specifically, this pressure P can be measured based on the rotational resistance (torque) of the rotating rotating disk 5b.

In addition, the calculation unit 8 estimates the thermosetting element MB based on the change in pressure P that the rotating disk 5b, which rotates and flows the target rubber R1 in a state after vulcanization hardening has started, receives from the target rubber R1 under conditions of constant temperature and constant rotational movement speed S.

The procedure for grasping the basic viscosity element MA and the thermosetting element MB is substantially the same as that of the previous embodiment, except that the die 3 and cylinder 2a are replaced with a container 2b, and the piston 5a is replaced with a rotating disk 5b. In addition, the various arrangements described in the previous embodiment can also be applied to this embodiment.

1 Flow characteristic estimation device 2a Cylinder (container)
2b Container (container)
Reference Signs List 3: die 4: flow path 4a: heating means 5: flow means 5a: piston 5b: rotating disk 5c: driving mechanism 6: temperature sensor 7: control unit 8: calculation unit R1: target rubber R2: comparison rubber

Claims (9)

A method for estimating flow characteristics of rubber, which estimates a basic viscosity element and a thermosetting element of viscosity during vulcanization of a target rubber in which a vulcanizing agent is blended with unvulcanized rubber, comprising the steps of:
While adjusting the heating condition of the flow path, the target rubber is caused to flow through the flow path by a flow means in a state before the start of vulcanization hardening and in a state after the start of vulcanization hardening;
The basic viscosity element is estimated based on a moving speed of the flow means which flows the target rubber in a state before the start of vulcanization curing under a constant temperature condition and a pressure which the flow means receives from the target rubber;
A method for estimating the flow characteristics of rubber, characterized in that the thermosetting element is estimated based on changes in the pressure that the flow means, which causes the target rubber to flow in a state after the start of vulcanization curing under constant temperature conditions and constant moving speed conditions, receives from the target rubber. The method for estimating the flow characteristics of rubber according to claim 1, wherein the target rubber is caused to flow in the flow path by the flow means in a state before the start of vulcanization hardening, and then the target rubber is continued to flow in the flow path by the flow means in a state after the start of vulcanization hardening. The method for estimating the flow characteristics of rubber according to claim 1, wherein the target rubber is caused to flow in the flow path by the flow means in a state before the start of vulcanization hardening, and then another target rubber is caused to flow in the flow path by the flow means in a state after the start of vulcanization hardening. A method for estimating flow characteristics of rubber, which estimates a basic viscosity element and a thermosetting element of viscosity during vulcanization of a target rubber in which a vulcanizing agent is blended with unvulcanized rubber, comprising the steps of:
The target rubber and a comparative rubber prepared to have an equivalent viscosity by compounding the target rubber but excluding the vulcanizing agent are prepared,
The target rubber and the comparative rubber are individually flowed through the same flow path by a flow means while adjusting the heating condition of the flow path,
estimating the basic viscosity element based on the moving speed of the flow means for flowing the comparative rubber or the target rubber in a state before the start of vulcanization curing under a constant temperature condition and the pressure that the flow means receives from the flowing rubber;
A method for estimating the flow characteristics of rubber, characterized in that the thermosetting element is estimated based on the pressure that the flow means for causing the comparison rubber to flow receives from the comparison rubber under constant temperature conditions and constant moving speed conditions, and the pressure that the flow means for causing the target rubber to flow receives from the target rubber after the start of vulcanization hardening. A method for estimating the flow characteristics of rubber according to any one of claims 1 to 4, in which a cylindrical body with a constant cross-sectional area is connected to the flow path, and a piston that moves the cylindrical body in the axial direction is used as the flow means. A rubber flow characteristic estimation method according to any one of claims 1 to 4, in which the inside of a cylindrical container with a constant cross-sectional area is used as the flow path, and a rotating disk that rotates around the cylindrical axis of the container inside the container is used as the flow means. A rubber flow characteristic estimation device that estimates a basic viscosity element and a thermosetting element of viscosity during vulcanization of a target rubber in which a vulcanizing agent is blended with unvulcanized rubber, comprising:
a flow path, a heating means for adjusting a heating condition for the flow path, a flow means for flowing the target rubber through the flow path in a state before the start of vulcanization hardening and in a state after the start of vulcanization hardening, and a calculation unit,
The calculation unit estimates the basic viscosity element based on a moving speed of the flow means that flows the target rubber in a state before the start of vulcanization hardening under a constant temperature condition and a pressure that the flow means receives from the target rubber,
A rubber flow characteristic estimation device, characterized in that the thermosetting element is estimated by the calculation unit based on the change in pressure that the flow means, which causes the target rubber to flow in a state after vulcanization hardening has started under constant temperature conditions and constant moving speed conditions, receives from the target rubber. A rubber flow characteristic estimation device that estimates a basic viscosity element and a thermosetting element of viscosity during vulcanization of a target rubber in which a vulcanizing agent is blended with unvulcanized rubber, comprising:
a flow path, a heating means for adjusting a heating condition for the flow path, a flow means for flowing the target rubber through the flow path in a state before the start of vulcanization hardening and in a state after the start of vulcanization hardening, and a calculation unit,
The target rubber and a comparative rubber prepared to have an equivalent viscosity by compounding the target rubber with the vulcanizing agent removed therefrom are individually flowed in the same flow path by a flow means while adjusting the heating condition of the flow path,
The calculation unit estimates the basic viscosity element based on a moving speed of the flow means which flows the comparative rubber or the target rubber in a state before the start of vulcanization curing under a constant temperature condition and a pressure which the flow means receives from the flowing rubber,
A rubber flow characteristic estimation device characterized in that the thermosetting element is estimated by the calculation unit based on the pressure that the flow means, which is causing the comparison rubber to flow, receives from the comparison rubber under constant temperature conditions and constant moving speed conditions, and the pressure that the flow means, which is causing the target rubber to flow in a state after the start of vulcanization hardening, receives from the target rubber. A method for simulating the flow of unvulcanized rubber, in which the basic viscosity element and the thermosetting element estimated by the rubber flow characteristic estimation method according to any one of claims 1 to 6 are used as the basic viscosity element and the thermosetting element, respectively, of viscosity when performing a flow simulation of the target rubber.

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