阅读说明：本技术 一种轮胎低滚阻配方设计测试方法 (Tire low rolling resistance formula design testing method ) 是由 季军胜 徐檬 詹迪 于 2021-10-08 设计创作，主要内容包括：本发明公开了一种轮胎低滚阻配方设计测试方法,具体步骤包括获取轮胎制作材料；通过轮胎硫化温度数据采集方法重复采集轮胎硫化周期内的硫化温度历程数据,其中轮胎硫化温度数据采集方法包括热电偶埋线测温试验法,以及FEA有限元分析法；根据轮胎硫化周期内的温度数据进行不同阶段的低滚阻配方配制,得到优化后的轮胎胶料配方；根据优化后的轮胎胶料配方对轮胎试做成品进行轮胎成品硫化和测试,并分析测试结果。本发明通过对硫化温度历程进行温度数据采集,并对数据进行拟合后形成新硫化条件,对新的配方胶料进行硫化获取动态粘性测试参数进行评估,确定设计配方是否满足设计。能够测试结果贴近轮胎成品结果,且配方开发周期更短,成本更低。(The invention discloses a tire low rolling resistance formula design testing method, which comprises the following specific steps of obtaining a tire manufacturing material; repeatedly acquiring vulcanization temperature history data in a tire vulcanization period by a tire vulcanization temperature data acquisition method, wherein the tire vulcanization temperature data acquisition method comprises a thermocouple buried wire temperature measurement test method and an FEA finite element analysis method; preparing low rolling resistance formulas in different stages according to temperature data in a tire vulcanization period to obtain an optimized tire rubber formula; and (4) performing vulcanization and test on the finished product of the tire trial according to the optimized tire rubber formula, and analyzing the test result. According to the invention, the temperature data acquisition is carried out on the vulcanization temperature process, the new vulcanization condition is formed after the data are fitted, the vulcanization is carried out on the rubber material with the new formula to obtain the dynamic viscosity test parameters for evaluation, and whether the design formula meets the design or not is determined. The test result is close to the finished tire result, the formula development period is shorter, and the cost is lower.)

1. A tire low rolling resistance formula design testing method is characterized by comprising the following steps:

obtaining a tire manufacturing material;

repeatedly acquiring vulcanization temperature history data in a tire vulcanization period by a tire vulcanization temperature data acquisition method, wherein the tire vulcanization temperature data acquisition method comprises a thermocouple buried wire temperature measurement test method and an FEA finite element analysis method;

preparing low rolling resistance formulas in different stages according to temperature data in a tire vulcanization period to obtain an optimized tire rubber formula;

and (4) performing vulcanization and test on the finished product of the tire trial according to the optimized tire rubber formula, and analyzing the test result.

2. The method for testing the low rolling resistance formula design of the tire as claimed in claim 1, wherein the thermocouple wire embedding temperature measurement test method comprises the following specific steps:

embedding a thermocouple at a collection point during tire blank molding, wherein the collection point comprises a tire tread, a tire side, a tire shoulder, a belt ply end point, a tire liner and a triangular rubber;

and arranging the green tire embedded with the thermocouple in a vulcanizing machine, switching on a recorder, starting a vulcanization period from mold closing to natural cooling, then switching off the thermocouple, and storing temperature measurement data to finish data acquisition.

3. The method for testing a tire low rolling resistance formulation as claimed in claim 1, wherein the FEA finite element analysis method comprises the following specific steps:

firstly, acquiring thermodynamic parameters, density and vulcanization characteristics of a tire component rubber material and steel wires used by the tire component rubber material, wherein the thermodynamic parameters comprise a thermal conductivity coefficient, a specific heat capacity and activation energy;

and establishing an FEA vulcanization simulation model, and calculating the vulcanization temperature history of the part rubber material in the vulcanization period through the model to finish data acquisition.

4. The method for testing the design of the tire low rolling resistance formula according to claim 1, wherein the step of formulating the low rolling resistance formula at different stages according to the temperature data in the tire vulcanization cycle to obtain the optimized tire rubber compound formula comprises the following specific steps:

firstly, selecting, proportioning and screening materials in different systems according to performance requirements, wherein the systems comprise a crude rubber system, a reinforcing filling system, an anti-aging system, an activation system, a vulcanization system, a softening and plasticizing system and a bonding system;

in the reinforcing filling system, white carbon black is used for replacing part of carbon black, or carbon black with larger particle size is used for reducing the weight fraction of the carbon black; or

In the raw rubber system, a part of low-hysteresis synthetic rubber is used together, and the mixed synthetic rubber is butadiene rubber or solution polymerized styrene-butadiene rubber.

5. The method for designing and testing a low rolling resistance formulation of a tire as claimed in claim 1, wherein the steps of vulcanizing and testing specifically comprise:

firstly, inputting or fitting collected vulcanization temperature history data and then inputting the data into a rubber processing instrument;

taking the vulcanization temperature history data as vulcanization conditions to carry out vulcanization operation;

secondly, setting a test program, reducing the temperature in the test cavity to 60 ℃, maintaining the temperature, and testing under the condition of 5% +/-0.1% double strain amplitude with the frequency of 10 Hz;

obtaining rubber material prepared at different stages, cutting samples, placing the samples in a testing cavity for vulcanization and testing to obtain output hysteresis factors, elastic modulus, viscous modulus and loss compliance, and evaluating according to a testing result.

6. The method for testing a tire low rolling resistance formulation as defined in claim 5, wherein during dynamic deformation, the strain γ is determined₀In dynamic deformation, Δ E is directly proportional to the viscous modulus G';

stress σ when determined₀During dynamic deformation, the delta E is in direct proportion to the loss compliance J';

current definite energy gamma₀·σ₀Dynamic deformation is that Δ E is proportional to the hysteresis factor tan δ;

where Δ E is the energy loss or dynamic hysteresis, loss compliance J ═ G ″/(G "2 + G '2), and G' is the elastic modulus.

Technical Field

The invention relates to the technical field of tire and rubber processing, in particular to a tire low rolling resistance formula design testing method.

Background

When the formula with low rolling resistance is used, the processes of undersize matching, large sample trial making, tire trial making and the like are needed, and the processes can be repeated for a plurality of times according to development progress and partial effect stages. The performance of the new formula is confirmed mainly in the small matching and large sample trial-making stages, the rubber material is vulcanized into a physical property sheet of 2mm on a flat vulcanizing machine at a constant temperature for a certain time, a dynamic viscoelasticity test is carried out, and a hysteresis factor of the newly developed formula is tested to estimate the rolling resistance performance of the new formula on a finished tire product. In addition, in the tire trial phase, the rolling resistance coefficient of the tire can be directly tested to determine the rolling resistance performance reduction amplitude of the new formula. And moreover, a finished tire can be dissected to sample for a dynamic viscoelasticity test, and a hysteresis factor of a newly developed formula is tested to determine the new formula to evaluate the rolling resistance of the tire.

The defect of the prior art is that the performance of the new formula on the finished tire is evaluated by a method for testing the dynamic viscoelasticity hysteresis factor of the constant-temperature vulcanizing physical sheet of the flat vulcanizing machine in the small matching and large sample trial-making stage. The constant-temperature vulcanization of the tire by using the flat vulcanizing machine is not constant-temperature vulcanization but variable-temperature vulcanization because the tire is a thick rubber product and rubber is a poor heat conductor. Because the difference of the vulcanization temperature courses influences the vulcanization crosslinking reaction and the difference of the aggregation state of the filler, the vulcanized rubber prepared by the two vulcanization courses has larger difference of performances.

The evaluation of the development effect of the new formula by testing the rolling resistance coefficient of the tire and the hysteresis factor of the anatomical sample of the finished tire in the tire trial-making stage is lagged, if the development effect of the formula in the stage does not meet the expectation, the small-fit, large-sample trial-making and tire trial-making processes are carried out again, the development period of the formula is longer, the tire trial-making process and a series of test processes are involved, and the development cost is higher.

Disclosure of Invention

The invention aims to overcome the defects of the prior art, and in order to realize the aim, a tire low rolling resistance formula design test method is adopted to solve the problems in the background technology.

A tire low rolling resistance formula design testing method comprises the following steps:

obtaining a tire manufacturing material;

repeatedly acquiring vulcanization temperature history data in a tire vulcanization period by a tire vulcanization temperature data acquisition method, wherein the tire vulcanization temperature data acquisition method comprises a thermocouple buried wire temperature measurement test method and an FEA finite element analysis method;

preparing low rolling resistance formulas in different stages according to temperature data in a tire vulcanization period to obtain an optimized tire rubber formula;

and (4) performing vulcanization and test on the finished product of the tire trial according to the optimized tire rubber formula, and analyzing the test result.

As a further aspect of the invention: the thermocouple buried wire temperature measurement test method comprises the following specific steps:

embedding a thermocouple at a collection point during tire blank molding, wherein the collection point comprises a tire tread, a tire side, a tire shoulder, a belt ply end point, a tire liner and a triangular rubber;

and arranging the green tire embedded with the thermocouple in a vulcanizing machine, switching on a recorder, starting a vulcanization period from mold closing to natural cooling, then switching off the thermocouple, and storing temperature measurement data to finish data acquisition.

As a further aspect of the invention: the FEA finite element analysis method comprises the following specific steps:

firstly, acquiring thermodynamic parameters, density and vulcanization characteristics of a tire component rubber material and steel wires used by the tire component rubber material, wherein the thermodynamic parameters comprise a thermal conductivity coefficient, a specific heat capacity and activation energy;

and establishing an FEA vulcanization simulation model, and calculating the vulcanization temperature history of the part rubber material in the vulcanization period through the model to finish data acquisition.

As a further aspect of the invention: the specific steps of preparing the low rolling resistance formula in different stages according to the temperature data in the tire vulcanization cycle to obtain the optimized tire rubber compound formula comprise:

firstly, selecting, proportioning and screening materials in different systems according to performance requirements, wherein the systems comprise a crude rubber system, a reinforcing filling system, an anti-aging system, an activation system, a vulcanization system, a softening and plasticizing system and a bonding system;

in the reinforcing filling system, white carbon black is used for replacing part of carbon black, or carbon black with larger particle size is used for reducing the weight fraction of the carbon black; or

In the raw rubber system, a part of low-hysteresis synthetic rubber is used together, and the mixed synthetic rubber is butadiene rubber or solution polymerized styrene-butadiene rubber.

As a further aspect of the invention: the vulcanization and test comprises the following specific steps:

firstly, inputting or fitting collected vulcanization temperature history data and then inputting the data into a rubber processing instrument;

taking the vulcanization temperature history data as vulcanization conditions to carry out vulcanization operation;

secondly, setting a test program, reducing the temperature in the test cavity to 60 ℃, maintaining the temperature, and testing under the condition of 5% +/-0.1% double strain amplitude with the frequency of 10 Hz;

obtaining rubber material prepared at different stages, cutting samples, placing the samples in a testing cavity for vulcanization and testing to obtain output hysteresis factors, elastic modulus, viscous modulus and loss compliance, and evaluating according to a testing result.

As a further aspect of the invention: during dynamic deformation, when strain gamma is determined₀In dynamic deformation, Δ E is directly proportional to the viscous modulus G';

stress σ when determined₀During dynamic deformation, the delta E is in direct proportion to the loss compliance J';

current definite energy gamma₀·σ₀Dynamic deformation is that Δ E is proportional to the hysteresis factor tan δ;

where Δ E is the energy loss or dynamic hysteresis, loss compliance J ═ G ″/(G "2 + G '2), and G' is the elastic modulus.

Compared with the prior art, the invention has the following technical effects:

by adopting the technical scheme, the vulcanization temperature history of a certain part or a plurality of parts of the tire is repeatedly obtained by adopting a thermocouple buried wire temperature measurement test or an FEA finite element analysis method for a plurality of times, and the vulcanization temperature history is input or fitted into a function and input into the rubber processing instrument. And designing a tire formula, setting a vulcanization condition and testing dynamic viscoelasticity according to a rubber processing instrument inputting a vulcanization temperature history, and outputting a hysteresis factor, an elastic modulus, a viscous modulus and a loss compliance. And finally, performing performance evaluation to determine whether the formula design meets the design target. Thereby solving the defects of the existing formula design and the problems that the vulcanized rubber has larger performance difference due to the difference of the vulcanization temperature course and the like. The formula design development period is shortened, and the formula development cost is reduced.

Drawings

The following detailed description of embodiments of the invention refers to the accompanying drawings in which:

FIG. 1 is a schematic step diagram of a tire low rolling resistance formulation test method according to some embodiments disclosed herein;

FIG. 2 is a flow chart of a tire low rolling resistance formulation testing method of some embodiments disclosed herein;

FIG. 3 is a schematic diagram of thermocouple in-line thermometry testing of collected tire tread curing temperature history in accordance with certain embodiments disclosed herein;

FIG. 4 is a schematic diagram of a fitted curve and fitted equation for a temperature rise over vulcanization history of 0-1.7min for some embodiments disclosed herein;

FIG. 5 is a schematic diagram of a fitted curve and fitted equation for a temperature rise profile of 1.7-45.0min for some embodiments disclosed herein;

FIG. 6 is a graph of a fitted curve and fitted equation for a temperature rise profile of 45.0-90.0min for some examples of the disclosure herein.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Referring to fig. 1 and fig. 2, in an embodiment of the present invention, a method for testing a low rolling resistance formula of a tire includes the following specific steps:

s1, obtaining tire manufacturing materials, specifically including manufacturing materials required in different stages of small matching of tire formula development, large sample trial making, tire trial making and the like;

s2, repeatedly acquiring vulcanization temperature history data in a tire vulcanization period by a tire vulcanization temperature data acquisition method, wherein the tire vulcanization temperature data acquisition method comprises a thermocouple buried wire temperature measurement test method and an FEA finite element analysis method;

in a specific embodiment, the thermocouple buried wire temperature measurement test method comprises the following specific steps:

embedding a thermocouple at a collection point during tire blank molding, wherein the collection point comprises a tire tread, a tire side, a tire shoulder, a belt ply end point, a tire liner and a triangular rubber;

and arranging the tire blank embedded with the thermocouple in a vulcanizing machine, switching on a recorder, starting timing from the mold closing time, unloading the tire after the tire is vulcanized for one period, placing the tire blank in a tire unloading frame for naturally cooling for one vulcanization period, switching off the thermocouple, and storing temperature measurement data, namely completing data collection.

In a specific embodiment, the FEA finite element analysis method specifically includes the steps of:

firstly, acquiring thermodynamic parameters, density and vulcanization characteristics of a tire component rubber material and steel wires used by the tire component rubber material, wherein the thermodynamic parameters comprise a thermal conductivity coefficient, a specific heat capacity and activation energy;

and establishing an FEA vulcanization simulation model, and calculating the vulcanization temperature history of the part rubber material in the vulcanization period through the model to finish data acquisition.

S3, preparing low rolling resistance formulas in different stages according to temperature data in a tire vulcanization cycle to obtain an optimized tire rubber formula, and the specific steps comprise:

firstly, selecting, proportioning and screening materials in different systems according to performance requirements, wherein the systems comprise a crude rubber system, a reinforcing filling system, an anti-aging system, an activation system, a vulcanization system, a softening and plasticizing system and a bonding system, and a part of special performance requirement formulas further comprise a flame retardant system and the like;

in the reinforcing filling system, white carbon black is used for replacing part of carbon black, or carbon black with larger particle size is used for reducing the weight fraction of the carbon black; or

In the raw rubber system, a part of low-hysteresis synthetic rubber is used together, and the mixed synthetic rubber is butadiene rubber or solution polymerized styrene-butadiene rubber.

Or reinforcing a formula vulcanization system, improving the crosslinking density and the like.

Specifically, the tire formula design process can generally have the following 3 stages, small matching, large sample trial making and tire trial making. Wherein the formulation is designed mainly at the minor-fit stage according to the tire performance requirements. The formulation design process is influenced by other properties besides hysteresis performance, such as magic triangles (abrasion, rolling resistance and wet grip) of the tire formulation design, and the formulation design is a balancing process with property emphasis. For the optimized formulation scheme of small fit, a series of tests are required for performance evaluation, including but not limited to test items of tensile strength, tearing, high-temperature physical properties, aging physical properties, abrasion, fatigue and the like.

And S4, vulcanizing and testing the finished product of the tire trial product according to the optimized tire rubber formula, and analyzing the test result.

Firstly, after performance evaluation, the dynamic viscoelasticity of the new formula needs to be tested, and the influence of the new formula on the rolling resistance performance of the tire is estimated.

The vulcanization and test comprises the following specific steps:

firstly, inputting or fitting collected vulcanization temperature history data and then inputting the data into a rubber processing instrument;

taking the vulcanization temperature history data as vulcanization conditions to carry out vulcanization operation;

secondly, setting a test program, reducing the temperature in the test cavity to 60 ℃, maintaining the temperature, and testing under the condition of 5% +/-0.1% double strain amplitude with the frequency of 10 Hz;

obtaining rubber material prepared at different stages, cutting samples, placing the samples in a testing cavity for vulcanization and testing to obtain output hysteresis factors, elastic modulus, viscous modulus and loss compliance, and evaluating according to a testing result.

In a specific embodiment, the strain γ is determined during dynamic deformation₀Delta E and viscosity at dynamic deformationThe modulus of elasticity G' is directly proportional;

stress σ when determined₀During dynamic deformation, the delta E is in direct proportion to the loss compliance J';

current definite energy gamma₀·σ₀Dynamic deformation is that Δ E is proportional to the hysteresis factor tan δ;

where Δ E is the energy loss or dynamic hysteresis, loss compliance J ═ G ″/(G "2 + G '2), and G' is the elastic modulus.

S5 testing rolling resistance coefficient of finished tire and dynamic viscoelasticity testing of anatomical sampling of finished tire

Specifically, after the performance of the plant proof is confirmed by the method introduced in step S4, the tire is tried after the proof test of the preferable scheme of the formula design in step S3 is performed. After the tire is vulcanized, testing the rolling resistance coefficient of a finished tire product;

the concrete test method refers to the correlation between single-point tests and measurement results of the GB/T29040-.

And (4) confirming the actual effect of the formula on the finished product through the rolling resistance coefficient test of the finished product of the tire. The tire finished product dissection sampling test confirms the actual contribution degree of the rolling resistance of the developed component.

Example (b):

example 1:

as shown in fig. 3, first, a tire curing tread component curing temperature history is collected according to step S1;

as shown in fig. 4, 5 and 6, in order to more accurately and conveniently record the tire tread vulcanization temperature history data into the rubber processing analyzer, the temperature rise curve of fig. 1 is fitted into the following three-section curve and a corresponding fitting equation is obtained.

The compound of the formulation of example 1 was vulcanized and tested using the test method of the present invention to confirm the dynamic viscoelasticity properties of the compound as shown in the following table:

performance index	Current formulations	Preferred formulation 1	Preferred formulation 2
				Hysteresis factor Tan delta	0.16	0.126	0.134
Elastic modulus G'	4.12	4.03	3.85
				Viscous modulus G ″)	0.66	0.51	0.52
Loss compliance J ″)	0.025	0.016	0.018

According to the test results, the preferable formula 1 with a lower rolling resistance coefficient can be selected and used for tire trial production.

Comparative example 2:

in order to develop an all-steel radial tire with the rolling resistance coefficient of less than 4.0, according to the prior experience, the influence ratio of the tire crown on the rolling resistance coefficient of a finished tire product is the largest and reaches more than 40%, so that a novel low-rolling-resistance tread formula needs to be developed.

According to the prior art formulation development method, a small fit test is first performed to confirm the preferred scheme. After multiple rounds of small fit tests and the current test method in the prior art, the test results of the preferred scheme are confirmed as follows:

performance index	Current formulations	Preferred formulation 1	Preferred formulation 2
				Hysteresis factor Tan delta	0.195	0.102	0.102
Elastic modulus E'	5.08	4.64	4.42
				Viscous modulus E ″)	0.99	0.47	0.45
Loss of powerCompliance J ″)	0.037	0.010	0.010

The loss compliance is comparable as a result of the dynamic viscoelasticity test of preferred embodiment 1 and preferred embodiment 2. And performing large sample trial and tire trial, testing the rolling resistance coefficient of the finished tire product or testing the viscoelasticity test result of the tread rubber compound by dissecting and sampling the finished tire product, and continuously performing scheme optimization.

Comparative example 3:

in order to actually verify the reliability of the test method, the preferable formula 1 and the preferable formula 2 are subjected to tire trial production, the rolling resistance coefficient of a finished product and the dynamic viscoelasticity of a tire finished product anatomical sampling tread rubber compound are tested, and the test results are summarized as follows:

performance index	Current formulations	Preferred formulation 1	Preferred formulation 2
				Coefficient of rolling resistance RR	5.3	3.9	4.1
Hysteresis factor Tan delta	0.158	0.125	0.133
				Elastic modulus E'	4.22	4.14	3.94
Viscous modulus E ″)	0.67	0.52	0.52
				Loss compliance J ″)	0.024	0.015	0.017

According to the test results, the optimal formula 1 is finally selected for formula limit, i.e. mass production. Meanwhile, the feasibility and the accuracy of the formula design and the testing method for the low rolling resistance of the tire introduced by the invention are also proved.

Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents, which should be construed as being within the scope of the invention.