CN105527194B - A method for detecting the processing performance of rubber used in tires - Google Patents

Abstract

The invention relates to a method for detecting the processing performance of rubber used for tires. The detection steps of the method are as follows: (1) Mooney viscosity test is carried out on the raw rubber sample using a Mooney viscometer; (2) The same kind of raw rubber sample with similar Mooney viscosity values tested in step (1) is cut Finally, put into the torque rheometer, fit the power law equation of the raw rubber sample: lgη=(A±0.03)lgγ+(B±0.06); (3) satisfy the raw rubber sample described in step (2) Power-law equation, then the rheological properties of the tire rubber are qualified. Beneficial effects: the present invention uses the torque rheometer capillary extrusion method to detect raw rubber system materials with similar Mooney viscosity values, and investigates the properties of raw rubber under different shear rates such as internal mixer mixing and extrusion in practical applications. Apparent viscosity, compared with existing methods, this method is more accurate for actual production results.

Description

A method for detecting the processing performance of rubber used in tires

technical field

The invention relates to a method for detecting rubber for tires, in particular to a method for detecting the processing performance of rubber for tires.

Background technique

In the tire industry, the index for investigating the processing performance of synthetic rubber is the Mooney viscosity value of raw rubber. However, the processing performance of the same rubber system material from different manufacturers and different batches may be different in actual applications, resulting in the quality of the compounded rubber. Unqualified phenomenon. Specifically, due to the single test condition of the Mooney viscosity value, the temperature is 100°C, the rotor speed is 2r/min, that is, the shear rate is about 1.31/s, but the temperature and shear rate in actual production are changing, and It is higher than the temperature and shear rate of the Mooney viscosity test, so the Mooney viscosity value of the material measured under a single condition cannot reflect the performance of the material during processing, and the Mooney viscosity value often appears in actual production Different similar manufacturers, or different batches of the same raw rubber material from the same manufacturer, have large differences in the Mooney viscosity of the compounded rubber materials, and there are large differences in processing performance.

Therefore, it is necessary to propose an effective technical solution to solve the above problems.

Contents of the invention

The present invention aims at the deficiencies of the above-mentioned prior art, and provides a method for detecting the processing performance of rubber for tires with high accuracy.

The technical scheme that the present invention solves the problems of the technologies described above is as follows:

A method for detecting rubber processing performance for tires, the detection steps of the method are as follows:

(1) Mooney Viscometer is used to test the raw rubber sample; the raw rubber sample is selected from different suppliers of the same synthetic rubber or different batches of products provided by the same supplier; the raw rubber At least 50 groups of samples;

(2) After cutting the same kind of raw rubber samples with similar Mooney viscosity values tested in step (1), put them into the torque rheometer;

Input the specific gravity value of the raw rubber sample on the torque rheometer, weigh the extrusion mass at each rate, record the values of apparent viscosity and shear stress, and fit according to the values of shear rate and apparent viscosity The power law equation of the raw rubber sample;

The power law equation is as follows:

lgη=(A±0.03)lgγ+(B±0.06)

In formula, η is apparent viscosity, and γ is shear rate, and A is n-1, and described n is non-Newtonian exponent, and B is 1gK, and described K is the apparent viscosity when shear rate is 0;

(3) If the power-law equation of the raw rubber sample described in step (2) is met, the rheological properties of the tire rubber are qualified; if the power-law equation of the raw rubber sample described in step (2) is not satisfied, the tire The rheological properties of rubber are unqualified.

Preferably, the torque rheometer is a single-screw extrusion, capillary die, and the specifications of the capillary die are L/D=10, L/D=20, L/D=30, L/D=40, The rotation speed of the extrusion screw is 1r/min-30r/min, the extrusion temperature is 110°C-170°C, and the holding time at each extrusion rate is 60s.

Preferably, the raw rubber sample is natural rubber or synthetic rubber; the synthetic rubber is butadiene rubber, styrene-butadiene rubber, EPDM rubber or butyl rubber.

Preferably, the styrene butadiene rubber is solution polystyrene butadiene rubber or emulsion polystyrene butadiene rubber. The solution-polystyrene butadiene rubber is non-oil-extended polystyrene-butadiene rubber or oil-extended polystyrene-butadiene rubber, and the emulsion polystyrene-butadiene rubber is non-oil-extended polystyrene-butadiene emulsion or polystyrene-butadiene oil-extended emulsion.

Preferably, the torque rheometer is a mixing type torque rheometer.

Beneficial effect:

The present invention adopts the torque rheometer capillary extrusion method to detect raw rubber system materials with similar Mooney viscosity values, and investigates the apparent viscosity of raw rubber under different shear rates such as internal mixer mixing and extrusion in practical applications , compared with existing methods, this method is more accurate to the actual production results.

For different manufacturers and different batches of the same synthetic rubber, the corresponding equation is fitted to detect the processing performance of the material in actual production. The materials satisfying the equation are considered to have similar processing performance of the compound rubber, and there is no need for subsequent processing. The process needs to be adjusted, and the materials that do not satisfy the equation, although the Mooney viscosity is similar, need to be adjusted to the appropriate process conditions in the actual processing process.

Description of drawings

Hereinafter, some specific embodiments of the present invention will be described in detail by way of illustration and not limitation with reference to the accompanying drawings. The same reference numerals in the drawings designate the same or similar parts or parts. Those skilled in the art will appreciate that the drawings are not necessarily drawn to scale. In the attached picture:

Fig. 1 is the double-logarithmic graph of the apparent viscosity and the shear rate of the non-oil-extended emulsion polystyrene butadiene rubber 1502 of Kumho Petrochemical in Example 1 of the present invention;

Fig. 2 is the double-logarithmic graph of the apparent viscosity and the shear rate of the non-oil-extended emulsion polystyrene butadiene rubber 1502 of Qilu Petrochemical in Example 2 of the present invention;

Fig. 3 is the double-logarithmic graph of the apparent viscosity and the shear rate of the non-oil-extended emulsion polystyrene butadiene rubber 1502 of Yangzi Petrochemical in Example 3 of the present invention;

Fig. 4 is the double-logarithmic graph of apparent viscosity and shear rate of the non-oil-extended emulsion polystyrene butadiene rubber 1502 of Jilin Petrochemical in Example 4 of the present invention;

Fig. 5 is the double-logarithmic graph of the apparent viscosity and the shear rate of the oil-extended polystyrene-butadiene rubber 6270M of Kumho Petrochemical in Example 5 of the present invention;

Fig. 6 is a double-logarithmic graph of apparent viscosity and shear rate of LG Chemical's oil-extended polystyrene butadiene rubber 2550 in Example 6 of the present invention.

detailed description

The invention relates to a method for detecting the processing performance of rubber for tires. The detection steps of the method are as follows:

(1) Mooney viscosity test is carried out on the raw rubber sample by Mooney viscometer; the raw rubber sample is selected from different suppliers of the same raw rubber or products of different batches provided by the same supplier; the raw rubber At least 50 groups of samples;

(2) After cutting the same kind of raw rubber samples with similar Mooney viscosity values tested in step (1) (the said similarity refers to the interval value of the standard value ± 3), put them into the torque rheometer;

Input the specific gravity value of the raw rubber sample on the torque rheometer, weigh the extrusion mass at each rate, record the values of apparent viscosity and shear stress, and fit according to the values of shear rate and apparent viscosity The power law equation of the raw rubber sample;

The power law equation is as follows:

lgη=(A±0.03)lgγ+(B±0.06)

In formula, η is apparent viscosity, and γ is shear rate, and A is n-1, and described n is non-Newtonian exponent, and B is 1gK, and described K is the apparent viscosity when shear rate is 0;

(3) If the power-law equation of the raw rubber sample described in step (2) is met, the rheological properties of the tire rubber are qualified; if the power-law equation of the raw rubber sample described in step (2) is not satisfied, the tire The rheological properties of rubber are unqualified.

As an embodiment of the present invention, the torque rheometer is a single-screw extruder and a capillary die; wherein the use of the following parameters is important for the accuracy of the detection method of the tire rubber processing performance of the present invention , specifically: the specifications of the capillary die are L/D=10, L/D=20, L/D=30, L/D=40, the rotating speed of the extrusion screw is 1r/min～30r/min, extruding The temperature is 110°C-170°C, and the holding time is 60s at each extrusion rate. The invention uses the capillary extrusion mode of the torque rheometer to measure the shear stress and apparent viscosity at different temperatures, different shear rates, and can reach 0-500S by setting the screw speed and using capillary tubes with different length-to-diameter ratios. The shear rate of ^-1 can cover the range of shear rate in the mixing and extrusion process of the internal mixer. According to a large number of experiments, the power law equation and coefficient range of different materials can be obtained to accurately predict the rubber in actual production. Processing stability.

As an embodiment of the present invention, the raw rubber sample is natural rubber or synthetic rubber; the synthetic rubber is butadiene rubber, styrene-butadiene rubber, EPDM rubber or butyl rubber. Preferably, the styrene-butadiene rubber is solution polystyrene butadiene rubber or emulsion polystyrene butadiene rubber; preferably, the solution polystyrene butadiene rubber is non-oil-extended polystyrene-butadiene rubber or oil-extended polystyrene-butadiene rubber, so The above-mentioned polystyrene-butadiene emulsion is non-oil-extended polystyrene-butadiene emulsion or polystyrene-butadiene oil-extended rubber.

Rubber for tires is a typical polymer. As the shear rate increases, the apparent viscosity of the polymer decreases. This phenomenon is called "shear-thinning". The fluid with shear thinning effect is called pseudoplastic fluid. The flow law of pseudoplastic fluid conforms to the Ostwald-de Wale power law equation (power law):

After taking the logarithm on both sides:

lgη=lgK+(n-1)lgγ

Wherein η is the apparent viscosity, γ is the shear rate, A is n-1, wherein n is the non-Newtonian index, B is lgK, and wherein K is the apparent viscosity when the shear rate is 0, which is called the viscosity constant.

By testing the rheological properties of different kinds of raw rubber, the corresponding shear rate and apparent viscosity value are obtained, and after taking the double logarithm of the two, the corresponding power law equation is fitted; the fitting result shows that the Mooney viscosity Different manufacturers with similar processing conditions and different batches of the same raw rubber satisfy the power law equation lg η=(A±0.03)lgγ+(B±0.06), and the processing performance of the raw rubber that satisfies this equation during use Stable; for materials that do not satisfy this equation, the processing parameters need to be adjusted in advance according to the actual situation. That is, the torque rheometer capillary extrusion method is used to detect raw rubber materials with similar Mooney viscosity values, and to predict the processing performance of such materials in actual production.

Different kinds of raw rubber or different batches of the same kind of raw rubber have different A values and B values, but the same kind of raw rubber materials have certain A values and B values. For all raw rubber materials: the range of A values is the standard The value of B is ± 0.03, and the range of B value is ± 0.06 of the standard value.

The Mooney viscosity of the raw rubber is tested with reference to the GB/T 1232.1 standard, and the disc shear viscometer is used for measurement. The measurement principle is: at 100°C, preheat for 1min, heat for 4min, and the rotor speed is 2r/min. The torque value, that is, the measured value of the Mooney viscosity.

The raw rubber for tires is extruded using the capillary extrusion mode of the torque rheometer, the temperature of the torque rheometer is raised to a preset temperature value, and the temperature of the screw and the extrusion die is set to 110°C to 110°C according to different rubber types. 170°C, set the extrusion rate program and time, and set the screw speed according to the reaction degree of the raw rubber type to temperature and shear force, so as to ensure that the shear rate covers the shear rate range in actual production. After the equipment is preheated and stabilized, the Cut the raw rubber into thin strips, start the test from the high aspect ratio (L/D=40) capillary die, record the mass of the extruded sample, the apparent viscosity and the value of pressure.

The test method uses a torque rheometer for testing. This equipment can be applied to rubber compound mixing and tire semi-component extrusion simulation at the same time. It has a wide range of applications and is used to guide the actual processing and production of the workshop.

In order to gain a deeper understanding of the processing performance of synthetic rubber, the Mooney viscosity value of raw rubber alone cannot fully reflect the performance of the material. Capillary rheometers can compare different structures of polymers. The molecular chain structure of the same polymer Differences, such as linearity, branch length, block structure, etc., are reflected in the capillary rheometer as differences in shear stress and apparent viscosity.

As an embodiment of the present invention, the torque rheometer is a mixing type torque rheometer, which is a multi-functional interchangeable building block torque measuring instrument, including a small closed mixer, a small screw Extruders and different types of extrusion dies. The extrusion die used in the present invention is a slit capillary die, that is, the capillary extrusion mode of the torque rheometer, which can simulate the actual processing process of the synthetic rubber and characterize the processing rheological properties of the synthetic rubber.

List the power law equation embodiment of specific raw rubber material below, to further describe the present invention, but protection scope of the present invention is not limited thereto:

Example 1:

Take Kumho Petrochemical’s non-oil-extended Emulsion Polystyrene Butadiene Rubber 1502, use a Mooney viscometer to measure the Mooney viscosity value of the raw rubber (ML1+4 100°C), then cut the raw rubber sample into strips, Variable instrument single-screw extrusion, test under the mode of capillary die, the specification of capillary die is L/D=20, L/D=30, L/D=40, set the temperature of screw and extrusion die to 150°C , the single-screw extrusion rate is 1r/min, 5r/min, 10r/min, 15r/min, 20r/min, 25r/min, 30r/min, and the retention time at each extrusion rate is 60s, input raw The specific gravity value of the glue, the extrusion mass at each rate was weighed, and the values of shear stress and apparent viscosity were recorded. According to the values of apparent viscosity and shear rate, the power law equation of the material was obtained as shown in Table 1. Fig. 1 shows the double-logarithmic curve of apparent viscosity and shear rate of Kumho Petrochemical's non-oil-extended emulsion polystyrene butadiene rubber 1502 in Example 1 of the present invention.

Example 2:

Take Qilu Petrochemical’s non-oil-extended Emulsion Polystyrene Butadiene Rubber 1502, use a Mooney viscometer to measure the Mooney viscosity value of the raw rubber (ML1+4 100°C), then cut the raw rubber sample into strips, and test it in the torque rheology The single-screw extrusion of the instrument is carried out under the mode of the capillary die. The specifications of the capillary die are L/D=20, L/D=30, and L/D=40. The temperature of the screw and the extrusion die is set at 150°C. The extrusion rate of the single screw is 1r/min, 5r/min, 10r/min, 15r/min, 20r/min, 25r/min, 30r/min, and the holding time at each extrusion rate is 60s, input raw rubber According to the specific gravity value, the extrusion mass at each rate is weighed to obtain the values of shear stress and apparent viscosity. According to the values of apparent viscosity and shear rate, the power law equation of synthetic rubber is shown in Table 1. Fig. 2 is a double-logarithmic curve of apparent viscosity and shear rate of non-oil-extended emulsion polystyrene butadiene rubber 1502 of Qilu Petrochemical in Example 2 of the present invention.

Example 3:

Take the non-oil-extended emulsion polystyrene butadiene rubber 1502 of Yangzi Petrochemical, and use the Mooney viscometer to measure the Mooney viscosity value of the raw rubber (ML1+4 100°C), and then cut the raw rubber sample into strips, and test it in torque rheology The instrument is single-screw extruded and tested under the mode of capillary die. The specifications of capillary die are L/D=20, L/D=30, L/D=40, and the temperature of screw and extrusion die is set at 150°C. The extrusion rate of the single screw is 1r/min, 5r/min, 10r/min, 15r/min, 20r/min, 25r/min, 30r/min, and the holding time at each extrusion rate is 60s, input raw rubber Weigh the extrusion mass at each rate, record the values of shear stress and apparent viscosity. According to the values of apparent viscosity and shear rate, the power law equation of the material is shown in Table 1. Fig. 3 is a double-logarithmic graph showing the apparent viscosity and shear rate of Yangzi Petrochemical's non-oil-extended emulsion polystyrene butadiene rubber 1502 in Example 3 of the present invention.

Example 4:

Take the non-oil-extended emulsion polystyrene butadiene rubber 1500E of Jilin Petrochemical Co., Ltd., and use the Mooney viscometer to measure the Mooney viscosity value of the raw rubber (ML1+4 100°C), and then cut the raw rubber sample into strips. The instrument is single-screw extrusion, and the test is carried out in the mode of capillary die. The specifications of capillary die are L/D=20, L/D=30, L/D=40, and the temperature of screw and extrusion die is set at 150°C. The extrusion rate of the single screw is 1r/min, 5r/min, 10r/min, 15r/min, 20r/min, 25r/min, 30r/min, and the retention time at each extrusion rate is 60s, input raw rubber Weigh the extrusion mass at each rate, record the values of shear stress and apparent viscosity. According to the values of apparent viscosity and shear rate, the power law equation of the material is shown in Table 1. Fig. 4 is a double-logarithmic curve of apparent viscosity and shear rate of Jilin Petrochemical's non-oil-extended emulsion polystyrene butadiene rubber 1502 in Example 4 of the present invention.

Example 5:

Take Kumho Petrochemical’s oil-soluble polystyrene-butadiene rubber 6270M, and use a Mooney viscometer to measure the Mooney viscosity value of the raw rubber (ML1+4 100°C), then cut the raw rubber sample into strips, and test it in torque rheology The single-screw extrusion of the instrument is carried out under the mode of the capillary die. The specifications of the capillary die are L/D=20, L/D=30, and L/D=40. The temperature of the screw and the extrusion die is set at 150°C. The extrusion rate of the single screw is 1r/min, 5r/min, 10r/min, 15r/min, 20r/min, 25r/min, 30r/min, and the holding time at each extrusion rate is 60s, input raw rubber Weigh the extrusion mass at each rate, record the values of shear stress and apparent viscosity. According to the values of apparent viscosity and shear rate, the power law equation of the material is shown in Table 1. Fig. 5 is a double-logarithmic graph showing the apparent viscosity and shear rate of Kumho Petrochemical's oil-extended styrene-butadiene rubber 6270M in Example 5 of the present invention.

Embodiment 6:

Take LG Chemical’s oil-extended styrene-butadiene rubber 2550, and use a Mooney viscometer to measure the Mooney viscosity value of the raw rubber (ML1+4 100°C), then cut the raw rubber sample into strips, and test it on the torque rheometer. Single-screw extrusion, test under the mode of capillary die, the specification of capillary die is L/D=20, L/D=30, L/D=40, set the temperature of screw and extrusion die at 150℃, single The extrusion rate of the screw is 1r/min, 5r/min, 10r/min, 15r/min, 20r/min, 25r/min, 30r/min, and the retention time at each extrusion rate is 60s, input raw rubber Specific gravity value, weighing the extrusion mass at each rate, recording the values of shear stress and apparent viscosity, according to the values of apparent viscosity and shear rate, the power law equation of the material is shown in Table 1. Fig. 6 is a double-logarithmic graph showing the apparent viscosity and shear rate of LG Chem's oil-extended styrene-butadiene rubber 2550 in Example 6 of the present invention.

Table 1 Comparison table of Mooney viscosity and power law equation of styrene-butadiene rubber from different manufacturers

As can be seen from Table 1, the Mooney viscosity value difference of the SBR1502 (containing 1500E) of four producers in the embodiment 1-embodiment 4 is within 5%, and the adjustment of process conditions is not carried out in the workshop use process, after After the capillary extrusion test, obtain the shear rate and the apparent viscosity value of the polymer melt, after taking double logarithm, draw lgη=(n-1) lgγ+lgK, wherein n-1=A ± 0.03 , lgK=B±0.06, according to the shear rate and apparent viscosity of SBR1502 from different manufacturers, A=-0.61, B=4.68.

The Mooney viscosity difference of these two kinds of oil-extended polystyrene-butadiene rubbers of embodiment 5 and embodiment 6 is also within 5%, which satisfies the oil-extended polystyrene-butadiene rubber (butadiene content 23.5%, oil-extended The power-law equation of 37.5phr) is lgη=(-0.80±0.03)lgγ+(4.83±0.06), and the power-law equations of Example 5 and Example 6 are within the scope of the power-law equation.

In the present invention, the specific fitting calculation process needs to be applied to Matlab or similar functional software, and the least square method is used to determine the fitting value with the smallest difference from the real value.

The present invention may be embodied in other specific forms without departing from the spirit or main characteristics of the invention. Therefore, no matter from which point of view, the above-mentioned embodiments of the present invention can only be regarded as descriptions of the present invention and cannot limit the present invention, and the claims have pointed out the scope of the present invention, and the above description does not point out the scope of the present invention. scope, therefore, within the meaning and scope equivalent to the claims of the present invention

Any changes should be considered to be included in the scope of the claims of the present invention.

Claims (5)

1. a kind of detection method of tyre rubber processing characteristics, it is characterised in that the detecting step of methods described is as follows：

(1) Mooney viscosity test is carried out using mooney's viscosimeter to rubber sample；

(2) after to rubber sample of the same race is cut similar in the Mooney viscosity value that is tested out in step (1), it is put into torque rheometer In；The rate of specific gravity of rubber sample is inputted on torque rheometer, weighs the extrusion quality under each speed, record apparent viscosity and The numerical value of shear stress, according to the numerical value of shear rate and apparent viscosity, fit the power-law equation of rubber sample；

The power-law equation is as follows：

Lg η=(A ± 0.03) lg γ+(B ± 0.06)

In formula, η is apparent viscosity, and γ is shear rate, and A n-1, the n are non-newtonian index, and B lgK, the K are shearing Apparent viscosity when speed is 0；

(3) power-law equation of step (2) the rubber sample is met, then the rheological property of the tyre rubber is qualified；It is discontented The power-law equation of sufficient step (2) the rubber sample, then the rheological property of the tyre rubber is unqualified.

2. the detection method of tyre rubber processing characteristics as claimed in claim 1, it is characterised in that the torque rheometer For Single screw extrusion, capillary die, the specification of capillary die is L/D=10, L/D=20, L/D=30, L/D=40, is squeezed The rotating speed for going out screw rod is 1r/min~30r/min, and extrusion temperature is 110 DEG C~170 DEG C, and when being kept under each rate of extrusion Between be 60s.

3. the detection method of tyre rubber processing characteristics as claimed in claim 1 or 2, it is characterised in that the rubber sample Product are natural rubber or synthetic rubber；The synthetic rubber is butadiene rubber, butadiene-styrene rubber, ethylene propylene diene rubber or butyl rubber Glue.

4. the detection method of tyre rubber processing characteristics as claimed in claim 3, it is characterised in that the butadiene-styrene rubber is Solution polymerized butadiene styrene rubber or emulsion polymerized styrene butadiene rubber；The solution polymerized butadiene styrene rubber is non-oil-filled solution polymerized butadiene styrene rubber or oil-filled solution polymerized butylbenzene Rubber, the emulsion polymerized styrene butadiene rubber are non-oil-filled emulsion polymerized styrene butadiene rubber or oil-filled emulsion polymerized styrene butadiene rubber.

5. the detection method of tyre rubber processing characteristics as claimed in claim 1 or 2, it is characterised in that the torque flow Become instrument to be kneaded type torque rheometer.