Method for detecting shrinkage of tire components and use thereof

Abstract

This invention discloses a method for detecting the shrinkage rate of tire components and its application, relating to the field of tire technology. By using the method of this invention to measure the shrinkage rate of tire components and selecting components with a shrinkage rate ≤10% for subsequent production, the risk of large fluctuations or unqualified shrinkage rates in tire components can be effectively reduced, avoiding the problem of product failure due to tearing or punctures caused by unqualified shrinkage rates.

Description

Technical Field

[0001] This invention relates to the field of tire technology, and more specifically to a method for detecting the shrinkage rate of tire components and its application. Background Technology

[0002] In the manufacturing process of construction machinery tires, the stability of the physical properties of semi-finished components directly determines the quality and reliability of the final product. Currently, the industry generally lacks standardized testing methods for the shrinkage rate of key semi-finished tire components (such as the airtight layer). During the production process, the compatibility of components is judged solely by experience, failing to accurately identify and control this core physical property indicator, shrinkage rate.

[0003] Due to the lack of an effective testing and screening mechanism, some semi-finished parts with excessive shrinkage rates or large fluctuations are directly introduced into subsequent molding processes. During tire vulcanization and molding, these substandard parts, due to unstable internal molecular chain orientation and uneven distribution of shrinkage stress, are highly susceptible to quality defects such as tearing, holes, and interlayer delamination. This not only significantly reduces the pass rate of the tire blank but also affects the structural strength, airtightness, and wear resistance of the finished tire. Ultimately, these potential quality problems will surface during product use, causing premature damage and performance degradation. This not only reduces the user experience but also increases customer complaints and after-sales maintenance costs. In severe cases, it can even damage the product's market reputation and hinder the company's market competitiveness.

[0004] Therefore, establishing a scientific and accurate method for detecting the shrinkage rate of tire components, and effectively screening out substandard components, has become a key requirement for solving current quality pain points in the industry and improving the stability of tire production and product reliability. Summary of the Invention

[0005] The technical problem to be solved by this invention is to overcome the shortcomings of the prior art and provide a method for detecting the shrinkage rate of tire components and its application. After measuring the shrinkage rate of tire components, components with a shrinkage rate ≤10% are selected for subsequent production. This can effectively reduce the risk of large fluctuations or unqualified shrinkage rates of tire components and avoid the problem of product failure in the market due to tearing or holes caused by unqualified shrinkage rates.

[0006] The technical solution of this invention is as follows:

[0007] On one hand, the present invention provides a method for detecting the shrinkage rate of tire components, comprising the following steps:

[0008] S1 uses a pad to roll up the parts after the film is calendered, and controls the film temperature T1 before rolling to meet the requirement of room temperature < T1 ≤ 40℃; after rolling, controls the storage environment temperature T2 to meet the requirement of 18℃ < T2 < 40℃, and the storage time is 6-7h; using a pad to roll up the parts helps to eliminate or stabilize the orientation of molecular chains in the parts, and ultimately stabilizes the shrinkage rate of the parts.

[0009] S2 guides the part apart on the molding machine, cuts out part samples in the guiding direction, marks the center line on the width direction of the part sample surface, and marks several reference lines of the same length as the center line at equal intervals on both sides of the center line to provide a comparison reference for subsequent calculation of shrinkage rate;

[0010] S3. Apply talcum powder evenly to the surface of the component sample without a center line and store it in a box. Apply talcum powder to the area of ​​the box that is in contact with the talcum powder-coated surface of the component sample. Keep the component sample flat and ensure that the edges do not contact the edges of the box. The storage time is 8.5-9.5 hours.

[0011] After the S4 reaches its storage time, measure and record the length of the center line and the baseline. During the measurement process, keep the component sample flat and do not pull it to avoid deformation of the component sample during the measurement process, which would affect the measurement results.

[0012] S5 calculates the shrinkage rate of the component sample at the center line or baseline based on the measured data = (initial length of center line or baseline - length of center line or baseline after storage) / initial length of center line or baseline × 100%. Take the maximum and minimum values ​​of the calculated shrinkage rate. If the difference between the two is > 5%, repeat the above operation and re-sample and test until the difference between the two is ≤ 5%. Finally, take the maximum value as the shrinkage rate of the component sample.

[0013] Preferably, in step S1, the padding cloth is made of polypropylene.

[0014] Preferably, in step S2, after the component is guided open on the molding machine, the frontmost 5-7m is cut off before the component sample is cut.

[0015] Preferably, in step S2, the initial length of the center line and the baseline is 300-350 mm.

[0016] Preferably, in step S2, the distance between the center line and the adjacent reference line, as well as between adjacent reference lines, is 150-200 mm.

[0017] Preferably, in step S2, the number of baselines on each side of the center line is 2-4.

[0018] Preferably, in step S2, the outermost reference line is more than 50 mm away from the two edges of the component sample along its length, and the center line and reference line are more than 150 mm away from the two edges of the component sample along its width.

[0019] Preferably, in step S3, the storage temperature is 35-45℃.

[0020] On the other hand, the present invention provides an application of the above-mentioned tire component shrinkage rate detection method. When the calculated shrinkage rate of the component sample is ≤10%, it is determined to be qualified; otherwise, it is determined to be unqualified and its use is prohibited.

[0021] Compared with the prior art, the present invention has the following advantages:

[0022] 1. This invention establishes a standardized testing process by specifying key parameters such as curling temperature, storage environment, and center line and baseline marking specifications, thus avoiding errors caused by human error. At the same time, it requires that the difference between the maximum and minimum shrinkage rates be ≤5%, ensuring the stability of the test data and significantly improving the accuracy and reliability of the shrinkage rate test results.

[0023] 2. This invention screens qualified parts with a shrinkage rate of ≤10%, eliminating semi-finished products with excessive or fluctuating shrinkage rates from the source. This effectively avoids quality defects such as tearing, holes, and interlayer peeling caused by uneven shrinkage stress during the molding and vulcanization process of unqualified parts, reduces production losses such as tire blank scrap and rework, and significantly improves the yield of tire production.

[0024] 3. The components screened by the method of this invention have consistent physical property parameters, which makes the core indicators of the finished tire, such as structural strength, air tightness, and wear resistance, more stable, reducing the risk of early failure during product use, and reducing customer complaints and after-sales costs; at the same time, the standardized testing process facilitates large-scale production control, helps enterprises establish a reliable product reputation, and enhances market competitiveness. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the airtight layer sample of Embodiment 1 of the present invention.

[0026] In the figure, 1. Airtight layer sample; 2. Center line; 3. Baseline. Detailed Implementation

[0027] To enable those skilled in the art to better understand the technical solutions of this invention, the technical solutions of this invention will be clearly and completely described below in conjunction with the embodiments of this invention.

[0028] Example 1

[0029] This embodiment tests the shrinkage rate of the tire airtight layer component, including the following steps:

[0030] S1 uses polypropylene padding to roll up the parts after the film is calendered, and controls the film temperature T1 before rolling to be 30℃; after rolling, controls the storage environment temperature T2 to be 25℃, and the storage time is 7h.

[0031] S2 guides the component apart on the molding machine. After guiding, the first 5mm of the front end is cut off, and then an airtight layer sample 1 with a length of 1500mm and a width of 900mm is cut according to the guiding direction. The airtight layer sample 1 is placed on a flat operating table. A center line 2 with a length of 300mm is marked on the width direction of the surface of the airtight layer sample 1. Three reference lines 3 with the same length as the center line 2 are marked on both sides of the center line 2 at equal intervals of 200mm. From left to right, they are called left reference line 1, left reference line 2, left reference line 3, center line 2, right reference line 1, right reference line 2, and right reference line 3 (e.g., left reference line 1, left reference line 2, left reference line 3, center line 2, right reference line 1, right reference line 2, and right reference line 3). Figure 1 (as shown)

[0032] S3. Apply talcum powder evenly to the surface of the airtight layer sample 1 without center line 2, and store it in a stainless steel box. Apply talcum powder to the area of ​​the box that is in contact with the surface of the airtight layer sample 1 that is coated with talcum powder. Keep the airtight layer sample 1 flat and do not let the edges contact the edges of the box. The storage time is 9 hours and the storage temperature is 40℃.

[0033] After S4 reaches the storage time, use a tape measure to measure and record the length of center line 2 and baseline 3. During the measurement process, keep the airtight layer sample 1 flat and do not pull it. The measurement results are shown in Table 1.

[0034] S5 calculates the shrinkage rate of the airtight layer sample 1 at the centerline 2 or baseline 3 based on the measured data: (initial length of the centerline or baseline - length of the centerline or baseline after storage) / initial length of the centerline or baseline × 100%. The calculation results are shown in Table 1. The difference between the maximum shrinkage rate of 8.3% and the minimum shrinkage rate of 6% is 2.3% < 5%, therefore the shrinkage rate of the airtight layer sample 1 is 8.3%. The shrinkage rate of the airtight layer sample 1 is < 10%, therefore it is deemed qualified and can be used for tire production.

[0035] Table 1. Calculation results of the centerline and baseline lengths of the airtight layer sample before and after storage, and the shrinkage rate at various points.

[0036]

[0037] Example 2

[0038] This embodiment tests the shrinkage rate of the tire airtight layer component, including the following steps:

[0039] S1 uses polypropylene padding to roll up the parts after the film is calendered, and controls the film temperature T1 before rolling to be 35℃; after rolling, controls the storage environment temperature T2 to be 28℃, and the storage time is 6h.

[0040] S2 guides the part apart on the molding machine. After guiding it apart, the first 7m at the front end is cut off. Then, an airtight layer sample 1 with a length of 1500mm and a width of 900mm is cut off according to the guiding direction. The airtight layer sample 1 is placed on a flat operating table. A center line 2 with a length of 350mm is marked on the width direction of the surface of the airtight layer sample 1. Two reference lines 3 with the same length as the center line 2 are marked on both sides of the center line 2 at equal intervals of 150mm. From left to right, they are called the first reference line, the second reference line, the center line 2, the first reference line, and the second reference line.

[0041] S3. Apply talcum powder evenly to the surface of the airtight layer sample 1 without center line 2, and store it in a stainless steel box. Apply talcum powder to the area of ​​the box that is in contact with the surface of the airtight layer sample 1 that is coated with talcum powder. Keep the airtight layer sample 1 flat and do not let the edges contact the edges of the box. The storage time is 8.5 hours and the storage temperature is 45℃.

[0042] After S4 reaches the storage time, use a tape measure to measure and record the length of center line 2 and baseline 3. During the measurement process, keep the airtight layer sample 1 flat and do not pull it. The measurement results are shown in Table 2.

[0043] S5 calculates the shrinkage rate of the airtight layer sample 1 at the centerline 2 or baseline 3 based on the measured data: (initial length of the centerline or baseline - length of the centerline or baseline after storage) / initial length of the centerline or baseline × 100%. The calculation results are shown in Table 2. The difference between the maximum shrinkage rate of 8.6% and the minimum shrinkage rate of 7.7% is 0.9% < 5%, therefore the shrinkage rate of the airtight layer sample 1 is 8.6%. The shrinkage rate of the airtight layer sample 1 is < 10%, therefore it is deemed qualified and can be used for tire production.

[0044] Table 2. Calculation results of the centerline and baseline lengths of the airtight layer sample before and after storage, and the shrinkage rate at various points.

[0045]

[0046] Example 3

[0047] This embodiment tests the shrinkage rate of the tire airtight layer component, including the following steps:

[0048] S1 uses polypropylene padding cloth to roll up the parts after the film is calendered, and controls the film temperature T1 before rolling to be 28℃; after rolling, controls the storage environment temperature T2 to be 20℃, and the storage time is 6.5h.

[0049] S2 guides the part apart on the molding machine. After guiding it apart, the first 5m at the front end is cut off. Then, an airtight layer sample 1 with a length of 1600mm and a width of 900mm is cut off according to the guiding direction. The airtight layer sample 1 is placed on a flat operating table. A center line 2 with a length of 320mm is marked on the width direction of the surface of the airtight layer sample 1. Four reference lines 3 with the same length as the center line 2 are marked on both sides of the center line 2 at equal intervals of 180mm. From left to right, they are called the first reference line to the fourth reference line, the center line 2, and the first reference line to the fourth reference line.

[0050] S3. Apply talcum powder evenly to the surface of the airtight layer sample 1 without center line 2, and store it in a stainless steel box. Apply talcum powder to the area of ​​the box that is in contact with the surface of the airtight layer sample 1 that is coated with talcum powder. Keep the airtight layer sample 1 flat and do not let the edges contact the edges of the box. The storage time is 8.5 hours and the storage temperature is 35℃.

[0051] After S4 reaches the storage time, use a tape measure to measure and record the length of center line 2 and baseline 3. During the measurement process, keep the airtight layer sample 1 flat and do not pull it. The measurement results are shown in Table 3.

[0052] S5 calculates the shrinkage rate of the airtight layer sample 1 at the centerline 2 or baseline 3 based on the measured data: (initial length of the centerline or baseline - length of the centerline or baseline after storage) / initial length of the centerline or baseline × 100%. The calculation results are shown in Table 3. The difference between the maximum shrinkage rate of 6.7% and the minimum shrinkage rate of 5.3% is 1.4% < 5%, therefore the shrinkage rate of the airtight layer sample 1 is 6.7%. The shrinkage rate of the airtight layer sample 1 is < 10%, therefore it is deemed qualified and can be used for tire production.

[0053] Table 3. Calculation results of the centerline and baseline lengths of the airtight layer sample before and after storage, and the shrinkage rate at various points.

[0054]

[0055] Comparative Example 1

[0056] The difference from Example 1 is that in step S1, the film temperature T1 before winding is controlled at 50°C. Finally, the calculated results of the length of the centerline 2 and baseline 3 of the airtight layer sample 1 before and after storage, as well as the shrinkage rate at various points, are shown in Table 4.

[0057] Table 4. Calculation results of the centerline and baseline lengths of the airtight layer sample before and after storage, and the shrinkage rate at various points.

[0058]

[0059] As can be seen from Table 4, the shrinkage rate of the airtight layer sample 1 measured in Comparative Example 1 reached 11.7%, and it was determined to be unqualified.

[0060] Take the airtight layer samples 1 of the same batch of Examples 1-3 and Comparative Example 1 for the production of 21.00R33 tires, and observe whether there are quality defects such as tearing, holes, and interlayer peeling in the tire embryos and tires. Count the qualified rate of the airtight layer of the tire embryos and the qualified rate of the tire appearance, as shown in Table 5:

[0061] Table 5 Qualified rates of the airtight layer of tire embryos and tire appearance of tires produced from the airtight layer components of Examples 1-3 and Comparative Example 1

[0062]

[0063] As can be seen from Table 5, due to the excessively high temperature of the film before curling in Comparative Example 1, the airtight layer components shrank severely during subsequent storage and shrinkage rate detection. The shrinkage rate of the airtight layer components > 10%, and the orientation of its internal molecular chains was unstable and the shrinkage stress distribution was uneven. During the production process of tire forming and vulcanization, it was extremely easy to cause fatal defects such as component tearing, holes, and interlayer peeling due to the imbalance of shrinkage stress, which directly led to none of the airtight layers of the tire embryos made being qualified, and the qualified rate of the airtight layer of the tire embryos was 0. Defects such as tearing and holes in the airtight layer at the tire embryo stage could not be repaired in subsequent production processes, and would directly be transmitted to the finished tire, resulting in appearance defects in the finished tire, and ultimately reducing the qualified rate of the tire appearance significantly to below 70%. At the same time, it would also cause the failure of core performances such as the structural strength and airtightness of the tire, and there was a risk of product market failure.

[0064] In summary, by using the method of the present invention to measure the shrinkage rate of tire components and screening components with a shrinkage rate ≤ 10% for subsequent production, the risk of large fluctuations in the shrinkage rate of tire components or unqualified shrinkage rate can be effectively reduced, and the problem of product market failure caused by component tearing and holes due to unqualified shrinkage rate can be avoided.

Claims

1. A method for detecting the shrinkage rate of tire components, characterized in that, Includes the following steps: S1 uses a pad to roll up the parts after the film is calendered, and controls the film temperature T1 before rolling to meet the requirement of room temperature < T1 ≤ 40℃; after rolling, controls the storage environment temperature T2 to meet the requirement of 18℃ < T2 < 40℃, and the storage time is 6-7 hours. S2 guides the part apart on the molding machine, cuts the part sample according to the guiding direction, marks the center line (2) on the width direction of the part sample surface, and marks several reference lines (3) of the same length as the center line (2) at equal intervals on both sides of the center line (2). S3. Apply talcum powder evenly to the surface of the component sample without center line (2) and store it in a box. Apply talcum powder to the area of ​​the box that is in contact with the surface of the component sample that is coated with talcum powder. Keep the component sample flat and do not let the edges contact the edges of the box. The storage time is 8.5-9.5h. After S4 reaches the storage time, measure and record the length of the center line (2) and the baseline (3). During the measurement process, keep the part sample flat and do not pull it. S5 calculates the shrinkage rate of the component sample at the center line (2) or the baseline (3) based on the measured data = (initial length of the center line or baseline - length of the center line or baseline after storage) / initial length of the center line or baseline × 100%. Take the maximum and minimum values ​​of the calculated shrinkage rate. If the difference between the two is > 5%, repeat the above operation and re-sample and test until the difference between the two is ≤ 5%. Finally, take the maximum value as the shrinkage rate of the component sample.

2. The method for detecting the shrinkage rate of tire components as described in claim 1, characterized in that, In step S1, the padding cloth is made of polypropylene.

3. The method for detecting the shrinkage rate of tire components as described in claim 1, characterized in that, In step S2, after the part is guided open on the molding machine, the frontmost 5-7m is cut off before the part sample is cut.

4. The method for detecting the shrinkage rate of tire components as described in claim 1, characterized in that, In step S2, the initial lengths of the center line (2) and the baseline (3) are 300-350 mm.

5. The method for detecting the shrinkage rate of tire components as described in claim 1, characterized in that, In step S2, the distance between the center line (2) and the adjacent baseline (3) and between adjacent baselines (3) is 150-200mm.

6. The method for detecting the shrinkage rate of tire components as described in claim 1, characterized in that, In step S2, the number of baselines (3) on each side of the center line (2) is 2-4.

7. The method for detecting the shrinkage rate of tire components as described in claim 1, characterized in that, In step S2, the outermost baseline (3) is more than 50 mm away from the two edges of the part sample along the length direction, and the center line (2) and baseline (3) are ≥150 mm away from the two edges of the part sample along the width direction.

8. The method for detecting the shrinkage rate of tire components as described in claim 1, characterized in that, In step S3, the storage temperature is 35-45℃.

9. The application of the tire component shrinkage rate detection method according to any one of claims 1-8, characterized in that, If the calculated shrinkage rate of the component sample is ≤10%, it is deemed qualified; otherwise, it is deemed unqualified and its use is prohibited.

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