CN113484506B - Method and equipment for measuring positive vulcanization time of white carbon black sizing material - Google Patents

Abstract

The invention relates to the application field of industries such as tires, rubber products and the like, in particular to a method for measuring the positive vulcanization time of white carbon black rubber, measuring equipment and a computer-readable carrier medium. A method for determining the positive vulcanization time of white carbon black rubber comprises the following steps: 1) Performing time scanning test on unvulcanized white carbon black reinforced sizing material in a rubber processing analyzer; 2) The time scanning range of the rubber processing analyzer is 0min to 45min; 3) According to the elastic modulus-time curve obtained by scanning, obtaining a vulcanization rate curve by first-order derivation; 4) Tangent line K1 is made at the position corresponding to the minimum value of the vulcanization rate curve, tangent line K2 is made at the vulcanization rate point corresponding to 45min, and Tk is positioned at the intersection point of K1 and K2; 5) The positive cure time Tc is calculated according to the following formula: tc=tk+0.5. The detection method is simple to operate, high in reproducibility and accurate in judgment.

Description

Method and equipment for measuring positive vulcanization time of white carbon black sizing material

Technical Field

The invention relates to the application field of industries such as tires, rubber products and the like, in particular to a method for measuring the positive vulcanization time of white carbon black rubber, measuring equipment and a computer-readable carrier medium.

Background

In the vulcanization process, the state that each physical and mechanical property of the vulcanized rubber reaches the optimal point is called positive vulcanization, and the time required for reaching positive vulcanization at a certain temperature is called positive vulcanization time. In ASTM D5289-2017 and GB/T16584-1996, a method for testing the vulcanization properties of rubber articles using a rotor-less rheometer is specified, wherein the time required for torque to reach ML+90% × (MH-ML) is taken as the positive vulcanization time to guide industrial production.

With the development of the use of white carbon black as a filler, particularly the promotion of the European Union tag method, the use amount of white carbon black in a formula is increased, but unlike a carbon black sizing material, the torque of the sizing material added with white carbon black is continuously increased along with the extension of the vulcanization time, as shown in fig. 1. This continuous rise in torque MH makes the measured time of the positive vulcanization of ML+90% × (MH-ML) inaccurate, and therefore, the performance of the cured formulation is not optimal or results in time waste, which affects the efficiency, and therefore, it is highly desirable to find a method for accurately measuring the positive vulcanization time of the white carbon black formulation.

Disclosure of Invention

In order to accurately represent the positive vulcanization time of the white carbon black sizing material, the invention provides a method for measuring the positive vulcanization time of a white carbon black formula, and the detection method is simple to operate, high in reproducibility and accurate in judgment.

In order to achieve the above purpose, the present invention adopts the following technical scheme:

a method for determining the positive vulcanization time of white carbon black rubber comprises the following steps:

1) Performing time scanning test on unvulcanized white carbon black reinforced sizing material in a rubber processing analyzer;

2) The time scanning range of the rubber processing analyzer is 0min to 45min;

3) According to the elastic modulus-time curve obtained by scanning, obtaining a vulcanization rate curve by first-order derivation;

4) Tangent line K1 is made at the position corresponding to the minimum value of the vulcanization rate curve, tangent line K2 is made at the vulcanization rate point corresponding to 45min, and Tk is positioned at the intersection point of K1 and K2;

5) The positive cure time Tc is calculated according to the following formula: tc=tk+0.5.

Preferably, the white carbon black is added in an amount of 20 parts or more based on 100 parts of the rubber matrix.

Preferably, the white carbon black includes, but is not limited to, precipitated white carbon black and fumed white carbon black.

Preferably, the rubber of the sizing material is one or a mixture of more than one of natural rubber, emulsion polymerized styrene-butadiene rubber, solution polymerized styrene-butadiene rubber and butadiene rubber.

Preferably, the rubber processing analyzer has a test frequency of 1.67Hz, a test temperature of 150-180 ℃ and a test strain of 7%. The 7% strain is 0.5 degree corresponding to the deflection angle of the rheometer, 1.67Hz is equal to the testing frequency of the rheometer, any one of the temperatures of 150-180 ℃ is selected, and the time obtained by the method is the positive vulcanization time at the temperature.

Further, the present invention also provides an assay device comprising a processor, a memory and a computer program stored on the memory and executable on the processor, the computer program when executed by the processor implementing the steps of:

1) Acquiring an elastic modulus-time curve obtained in the step 3) in the method, and obtaining a vulcanization rate curve by first-order derivation;

2) Tangent line K1 is made at the position corresponding to the minimum value of the vulcanization rate curve, tangent line K2 is made at the vulcanization rate point corresponding to 45min, and Tk is positioned at the intersection point of K1 and K2;

3) The positive cure time Tc is calculated according to the following formula: tc=tk+0.5.

Further, the present invention also provides a non-transitory computer readable carrier medium storing program instructions, the computer readable storage medium storing thereon a computer program which when executed by a processor realizes the steps of:

1) Acquiring an elastic modulus-time curve obtained in the step 3) in the method, and obtaining a vulcanization rate curve by first-order derivation;

2) Tangent line K1 is made at the position corresponding to the minimum value of the vulcanization rate curve, tangent line K2 is made at the vulcanization rate point corresponding to 45min, and Tk is positioned at the intersection point of K1 and K2;

3) The positive cure time Tc is calculated according to the following formula: tc=tk+0.5.

By adopting the technical scheme, the detection method is simple to operate, high in reproducibility and accurate in judgment.

Drawings

FIG. 1 shows the vulcanization curve (vulcanization temperature 160 ℃ C. For 15 min) of the formulation of the example.

FIG. 2 shows the vulcanization curve (vulcanization temperature 160 ℃ C. For 30 min) of the formulation of the example.

FIGS. 3 and 4 show the time for positive vulcanization obtained according to the method of the invention for the formulation of the examples.

Detailed Description

The formulation of the example was designed, in particular as follows in Table 1 (phr):

table 1 example formulation table

Raw materials	Formulation of
		Solution polymerized styrene butadiene rubber A	75.0
Solution polymerized styrene butadiene rubber B	34.5
		Carbon black N134	16.0
White carbon black	75.0
		Silane coupling agent Si69	7.5
Softening oil	10.0
		Others	25.5
Total parts by weight	243.5

Details of raw materials used in the formulation:

solution polymerized styrene butadiene rubber a, HPR850, JSR chemical product;

solution polymerized styrene-butadiene rubber B, E581, rayleigh chemical product (oil-containing styrene-butadiene rubber, rubber 25.0phr, softening oil 9.5 phr);

carbon black N134, cabot product;

white carbon black, 1165MP, soxhlet chemical products;

silane coupling agent Si69, macro-cypress chemical product;

softening oil, TDAE, hansheng chemical products;

the rest raw materials are all commercial industrial grade products.

After the formula is mixed and sulfur is added by an internal mixer, rotor-free rheometer tests are respectively carried out at 2 time points (15 min and 30 min) at the vulcanization temperature of 160 ℃, the obtained curves are shown in fig. 1 and 2, the positive vulcanization time is 9.98min and 12.22min respectively, the visible torque is continuously increased along with the time extension, and the positive vulcanization time of the rheometer tests is correspondingly prolonged.

And sampling to perform RPA2000 time scanning under the test conditions of strain 7%, frequency 1.76Hz, test temperature 160 ℃ and time scanning range 0-45min, deriving the obtained curve to obtain a vulcanization rate curve, and processing according to the method of the invention to obtain positive vulcanization time 9.04min.

The press vulcanization was performed at 160℃for 8min, 9min, 10min, 12min, and the performance test was performed, and the results are shown in Table 2.

Hardness: the hardness at room temperature was determined based on GB/T531.1-2008. The results are shown in table 2, the greater the value, the higher the hardness.

300% modulus and tensile strength, elongation at break: the 300% elongation stress measured based on GB/T528-2009 shows a "300% modulus". Further, the load at break during the same test is shown as "tensile strength", and the elongation at break is shown as "elongation at break". Each of these is shown in table 2, the larger the value, the higher the enhancement.

TABLE 2 physical Property data

Test item	160℃*8min	160℃*9min	160℃*10min	160℃*12min
					Hardness of	67	68	68	69
300% elongation/MPa	9.69	10.41	11.13	12.24
					Tensile Strength/MPa	19.79	20.93	20.65	19.87
Elongation at break/%	533.5	520.4	491.2	449.2
					Tensile product *1	10558	10892	10143	8926

*1, annotating: the tensile product is tensile strength multiplied by elongation at break, and a larger value indicates better physical properties

As can be seen from the data in table 2 above, the tensile product of the vulcanizate at 160 ℃ for 9min is the greatest, indicating that its physical properties are better and more consistent with the definition of the time being vulcanized. The vulcanization time obtained by the method is more in line with the actual situation, and the efficiency and the physical properties of vulcanized rubber are better.

The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art. The generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims (5)

1. A method for determining the positive vulcanization time of white carbon black rubber comprises the following steps:

1) Performing time scanning test on unvulcanized white carbon black reinforced sizing material in a rubber processing analyzer; the addition part of the white carbon black in the white carbon black sizing material is more than or equal to 20 parts by calculating 100 parts of the rubber matrix; the test frequency of the rubber processing analyzer is 1.67Hz, the test temperature is 150-180 ℃, and the test strain is 7%;

2) The time scanning range of the rubber processing analyzer is 0min to 45min;

3) According to the elastic modulus-time curve obtained by scanning, obtaining a vulcanization rate curve by first-order derivation;

4) Tangent line K1 is made at the position corresponding to the minimum value of the vulcanization rate curve, tangent line K2 is made at the vulcanization rate point corresponding to 45min, and Tk is positioned at the intersection point of K1 and K2;

5) The positive cure time Tc is calculated according to the following formula: tc=tk+0.5.

2. The method for determining the positive vulcanization time of white carbon compound of claim 1, wherein the white carbon comprises, but is not limited to, precipitated white carbon and fumed white carbon.

3. The method for determining the positive vulcanization time of white carbon black rubber according to claim 1, wherein the rubber of the rubber compound is one or more of natural rubber, emulsion polymerized styrene-butadiene rubber, solution polymerized styrene-butadiene rubber and butadiene rubber.

4. An assay device comprising a processor, a memory and a computer program stored on the memory and executable on the processor, the computer program when executed by the processor performing the steps of:

1) Acquiring an elastic modulus-time curve obtained in the step 3) in the method of claim 1, and obtaining a vulcanization rate curve by first-order derivation;

2) Tangent line K1 is made at the position corresponding to the minimum value of the vulcanization rate curve, tangent line K2 is made at the vulcanization rate point corresponding to 45min, and Tk is positioned at the intersection point of K1 and K2;

3) The positive cure time Tc is calculated according to the following formula: tc=tk+0.5.

5. A non-transitory computer readable carrier medium storing program instructions, characterized in that the computer readable storage medium has stored thereon a computer program which when executed by a processor realizes the steps of:

1) Acquiring an elastic modulus-time curve obtained in the step 3) in the method of claim 1, and obtaining a vulcanization rate curve by first-order derivation;

2) Tangent line K1 is made at the position corresponding to the minimum value of the vulcanization rate curve, tangent line K2 is made at the vulcanization rate point corresponding to 45min, and Tk is positioned at the intersection point of K1 and K2;

3) The positive cure time Tc is calculated according to the following formula: tc=tk+0.5.

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