TWI774987B - Inspection method and inspection device - Google Patents

Abstract

The present invention provides an inspection technique capable of detecting excess moisture after the dehydration/drying step and before molding. The crumb polymer inspection method of the present invention is characterized by continuously supplying the crumb polymer after polymerization, dehydration and drying, and detecting crumbs containing excessive moisture in the crumb polymer.

Description

Inspection method and inspection device

The present invention is a technique for checking the presence or absence of moisture in the supplied and transferred polymer in the form of crumbs.

As an example of the manufacturing process of the crumb polymer, the manufacturing process of synthetic rubber such as butadiene rubber will be briefly described.

A butadiene solution as a raw material is prepared, a catalyst is added, and it is polymerized to form a polymer solution (polymerization step). The obtained polymer solution is subjected to steam treatment to recover the polymer in the form of a scrap (desolvation step). The polymer containing water is dehydrated by an extruder, and is dried by hot air or the like to be in the form of dry crumbs (dehydration/drying step). The polymer in the form of crumbs is compressed and molded (molding step). Furthermore, generally speaking, particles with a particle size of about 3 to 10 mm generated during the production of synthetic rubber are called crumbs.

The invention of the present application relates to the molding step. The molding step will be described in more detail.

Using a press molding machine (usually referred to as a press machine, hereinafter referred to as a press machine), the semi-finished product in the form of crumbs or powder is press-molded into a press-molded product with a straight hexahedron shape (usually called a press-molded product). moldings, hereinafter referred to as moldings).

At this time, the polymer in the form of crumbs is automatically measured and adjusted within the specified weight range. It is molded into a molded product within a specified weight range, and the weight is checked, the rubber molded product is covered with a film packaging bag such as polyethylene film, polystyrene film, etc. Ship to users.

Furthermore, on the user side, the molded article is melted or dissolved, vulcanized, and processed.

As mentioned above, in the process of synthetic rubber, moisture is not necessarily used, so it is removed during the dehydration/drying step. However, water that is not completely removed in the dehydration/drying step actually remains. In moldings containing excess moisture, there is a risk of creating cosmetic defects or malfunctioning on the part of the user.

In view of this, in the previous general molding step, after the molding and before unloading, the inspector conducts a visual inspection of the appearance, thereby detecting the molding containing excessive moisture. However, the inspector was unable to detect excess moisture inside the molded part. In addition, the burden of the inspector is also greater.

In Patent Document 1, a technique is proposed in which a sample rubber can be irradiated with infrared rays through a transparent plate using an infrared-transmitting transparent plate having a smooth surface while pressing the rubber, whereby the test sample can be measured with high accuracy in a short period of time. The moisture content of the sample rubber. prior art literature Patent Literature

Patent Document 1: Japanese Patent Laid-Open No. 2004-020192

[Problems to be Solved by Invention]

According to the technique of Patent Document 1, by measuring the moisture content of the sample rubber and confirming that it is equal to or less than a specific value, it can be estimated that there is no excess moisture in the molded article to be a product.

However, the inventor of the present application, after researching the mechanism of excess water retention, believes that the regularity of whether excess water will remain is low and difficult to predict. The molded part of the product also does not contain excess moisture.

The present invention has been made in view of the above problems, and an object of the present invention is to provide an inspection technique capable of detecting excess moisture after the dehydration/drying step and before molding. [Technical means to solve problems]

The present invention to solve the above-mentioned problems is an inspection method for continuously supplying a crumb-like polymer after polymerization, dehydration and drying, and detecting crumbs containing excessive moisture in the crumb-like polymer.

By detecting crumbs containing excess moisture in crumbs prior to molding of the molded part, excess moisture contained within the previously undetectable molded part can be detected.

In the above-mentioned invention, it is preferable to measure the temperature of the above-mentioned crumb-like polymer, and to detect crumbs containing excessive moisture based on the temperature difference.

In the above invention, it is preferable to set as follows: the temperature of each measurement point is measured for the continuously supplied crumb polymer, the average temperature of a plurality of measurement points is obtained, and the measurement point whose temperature is lower than the average temperature is detected. Corresponding crumbs.

In the said invention, it is preferable to set so that the chip|tip corresponding to the measurement point whose temperature difference with respect to the said average temperature is 9.5 degreeC or more is detected.

This makes it possible to detect a low temperature portion due to the effect of vaporization of excess moisture or the effect of hard temperature rise.

In the above invention, it is preferable to set the average temperature of the polymer at the time of supplying the polymer in the form of crumbs after dehydration and drying to 40 to 70°C.

In this way, the above-mentioned effects caused by excessive moisture are easily highlighted.

In the above-mentioned invention, it is preferable to set as follows: the above-mentioned crumbs containing excessive moisture are in the form of lumps.

Crumbs that contain excess moisture tend to agglomerate. Moreover, if it is a block shape, it becomes easy to detect the influence of vaporization and temperature rise.

In the above-mentioned invention, it is preferable to set the moisture content of the crumbs containing excess moisture to 1 mass % or more.

The present invention to solve the above-mentioned problems is an inspection apparatus comprising: a supply mechanism for continuously supplying the polymer in the form of crumbs after polymerization, dehydration and drying; the temperature of the polymer; and a judging mechanism that calculates a temperature difference from the average temperature using the above-mentioned temperature measuring mechanism, and detects chips containing excess moisture based on the temperature difference.

In the above-mentioned invention, it is preferable to set as follows: the above-mentioned excessive moisture inspection means is a temperature recording camera. [Effect of invention]

The present invention can detect excess moisture after the dehydration/drying step and before molding.

~System Components~

FIG. 1 is a system configuration diagram of an embodiment of the present invention.

The system is equipped with a continuous supply mechanism, an excess moisture inspection mechanism, a molded part equivalent weight measurement mechanism, a molded part molding mechanism, a carry-out mechanism, and a control mechanism, and executes a series of actions.

The continuous feeding mechanism is, for example, the vibrating feeder 1 . The vibrating feeder 1 continuously feeds the polymer 2 in the form of crumbs after the dehydration/drying step 8 to the system.

The excess moisture inspection means is, for example, the temperature recording camera 3 . The temperature recording camera 3 is arranged on the vibrating feeder 1, and detects excess moisture by detecting the temperature not rising due to insufficiently dried crumbs (see below for details).

The equivalent weight measuring mechanism of the molded part is, for example, a measuring device 6 having a hopper. The hopper is arranged between the continuous supply mechanism and the molding device forming mechanism. The hopper has an upper hopper and a lower hopper. By controlling the action of the upper hopper and the lower hopper, and using the weighing device 6 to measure the weight of the crumb polymer stored in the hopper, the weight of the crumb polymer equivalent to the molding is measured.

The molded article molding mechanism is, for example, a press molding machine (pressing machine) 7 . A crumb-like polymer in an amount measured by a molded product equivalent weight measuring mechanism is supplied, and pressure-molded is applied to form a molded product.

The unloading mechanism is, for example, the conveyor 14 . A weight measuring device 15 is installed in the middle of the conveyor 14 .

The control device 30 inputs the excess moisture inspection information from the excess moisture inspection mechanism 3, and inputs the molded part weight information from the weight measuring device 15, and executes the division control. That is, a molded product whose excess moisture is not detected and whose weight is within the normal range is transferred to the next step (packaging step) 9 as a regular product 12, and a molded product whose excess moisture is detected or/and whose weight is outside the regular range is regarded as a regular product 12. Non-compliant products 13 are rejected and sent to another step 10 (reprocessing).

Excessive moisture is not a substantial defect, and can be reused as a material by reprocessing the crumbed polymer containing excess moisture.

~Basic concept of this application~ The invention of the present application focuses on the temperature difference caused by excess moisture. Figure 2 shows the results of a verification test as a basis for the basic concept of the present invention. The vertical axis of FIG. 2 is the moisture content (mass %) of the chips, and the horizontal axis is the value obtained by [(WP surface temperature)−(chip average temperature)]. Here, the so-called WP surface temperature refers to the measured temperature of a portion of the chips that is presumed to contain excessive moisture, and the so-called chip average temperature refers to the average temperature of a plurality of measuring points.

The average temperature of the polymer in the form of crumbs after the dehydration/drying step and then continuously fed to the molding step after polymerization is 40 to 70°C. In more detail, in the verification test conducted in winter, the average temperature of the crumb polymer was 48.8°C, and in the verification test conducted in summer, the average temperature of the crumb polymer was 60.7°C.

In addition, the average outside temperature of the verification test site was about 6°C in winter, and the average outside temperature in summer was about 26°C. The average temperature of the crumb polymer after the dehydration/drying step is affected by the outside air temperature.

Regardless of whether it is summer or winter, the temperature of the crumb polymer varies from -20°C to +15°C with the average value as the center. The moisture content of the crumb polymer at this time was investigated.

From the results in Fig. 2, the following can be seen. The moisture content is extremely low in crumbs where the WP surface temperature is near or higher than the average crumb temperature. On the other hand, in the crumbs whose WP surface temperature is lower than the average temperature, the moisture content is higher. In particular, when the temperature difference between the WP surface temperature and the average temperature of the chips is 9.5°C or more, the moisture content of the chips is very high.

In addition, the crumbs containing excessive moisture tend to be easily agglomerated. The portion of the block containing excess moisture is defined as WET POINT (WP). It is presumed that the crumbs after the dehydration/drying step have a relatively high temperature, and in crumbs containing excess moisture, the heat of the crumbs is captured when the moisture vaporizes, or the temperature becomes corresponding to the increase of the excess moisture. Difficult to ascend.

The same tendency can be seen in both summer and winter. In one example of the test, in winter, the surface temperature of the crumb is 48.8 °C, and the WP is 35.4 °C (the temperature difference between the surface temperature of the crumb and the WP is 13.4 °C), and in summer, the surface temperature of the crumb is 60.7 °C, and the WP is 47.4 °C. °C (the temperature difference between the chip surface temperature and the WP is 13.3 °C).

From this result, it can be judged that by measuring the temperature of the crumb-like polymer, crumbs containing excessive moisture can be detected, and in particular, by focusing on the temperature difference, WET POINT can be reliably detected regardless of the outside air temperature. . In particular, it is possible to detect WET POINT of chips containing 1 mass % or more of excess moisture.

~Detection of crumbs containing excess moisture (WET POINT)~ WET POINT is detected based on the temperature difference. More specifically, the average temperature of a plurality of measurement points of the chips is obtained, and the portion of the measurement point whose temperature is lower than the average temperature is set as the WET POINT, whereby the WET POINT can be detected.

WET POINT can be detected with higher accuracy by setting the measurement point portion where the difference from the above average temperature is 9.5° C. or more as WET POINT.

The average temperature of the chips can be obtained, for example, by the following method.

FIG. 3 shows an example of temperature measurement. The temperature measuring mechanism is a temperature recording camera. Able to achieve 30 frames / second camera. As the temperature recording camera 3, for example, CPA-L25B manufactured by CHINO Corporation can be used.

The crumbs are photographed and imaged using a thermographic camera, and the temperature in each image is measured in units of pixels within the image range (dashed line shown) corresponding to a specific range (eg, 600 mm x 500 mm). The average temperature of the chips can be obtained from the measured temperature of each pixel.

When obtaining the average temperature, the measurement points are preferably 100 to 100,000, more preferably 1,000 to 100,000, and particularly preferably 10,000 to 100,000. WET POINT can be detected with high accuracy.

Further, pixels whose temperature is lower than the average temperature by a predetermined value or less (eg, 9.5° C.) are extracted to detect WET POINT.

~Estimated mechanism of excess moisture production~ The prerequisite is that, by going through the dehydration/drying step, no crumbs with excess moisture are produced. Nonetheless, crumbs containing excess moisture are actually produced. Its mechanism is discussed.

In the dehydration/drying step, moisture is discharged to the outside. At this time, the small pieces are firmly adhered to the inner wall surface of the discharge portion. The small pieces absorb a part of the moisture discharged to the outside.

There is a risk that the small pieces containing moisture are peeled off at some point and mixed into the crumbs supplied to the next step (molding step).

Therefore, it is very difficult to predict the generation of crumbs containing excess moisture.

~About the crumb block~ As a feature of the crumbs, the crumbs have adhesiveness, and the crumbs are easily bonded to each other, and it is presumed that the crumbs are likely to be formed. Presumably, crumbs containing excess moisture were mixed in, thereby causing WET POINT to be generated.

On the other hand, if the excess water is concentrated and exists, the influence of vaporization and the like are likely to be prominent, and the low-temperature portion can be easily detected (see FIG. 3 ).

Therefore, the present application is suitable for the detection of WET POINT, but it is not limited to crumb blocks, and can also be applied to crumbs.

Furthermore, the particle size of the general crumbs is 3 to 10 mm. In this application, those with a particle size of 20 mm or more are referred to as crumbs.

~Effect~ In summary, excess moisture can be detected after the dehydration/drying step and before the molding is formed. As a result, excess moisture inside the molded part can also be detected.

Furthermore, since excess moisture can be detected before the molding is formed, there is also a possibility, for example, that the crumb-like polymer containing excess moisture is removed on the track that falls toward the press.

However, crumb polymers are cohesive and the particles tend to stick to each other. As a result, the particle size becomes non-uniform and unpredictable behavior. In the case of rejecting the crumb polymer containing excess moisture on the track falling toward the press, a complicated mechanism is required. On the other hand, as long as the molded part containing excess moisture is removed after the molded part is formed, it can be easily and surely removed.

According to the above, no configuration or steps other than a temperature recording camera and simple control are required. Excessive moisture can be easily and reliably detected without adding new components or steps to the existing process. It will not affect the quality of the products.

In addition, by focusing on the temperature difference, it is possible to reliably perform detection without depending on the outside air temperature.

~The object's crumb polymer~ The crumb polymer that forms the object of the molding is a vulcanizable rubber, for example, natural rubber (NR), isoprene rubber (IR), styrene butadiene rubber (SBR), butadiene rubber. (BR), chloroprene rubber (CR), butyl rubber (IIR), nitrile rubber (NBR), ethylene propylene rubber (EPM, EPDM), chlorosulfonated polyethylene rubber (CSM), acrylic rubber ( ACM), urethane rubber (U), silicone rubber (VMQ, PVMQ, FVMQ), fluorine rubber (FKM), polyvulcanized rubber (T), etc. In particular, application to butadiene rubber (BR) is preferred for the present invention. In the verification test, butadiene rubber was used.

~Summarize~ The average temperature of the polymer in the form of crumbs after the dehydration/drying step and then continuously fed to the molding step is 40 to 70°C. For example, in the verification test conducted in winter, the average temperature was 48.8°C, and in the verification test conducted in summer, the average temperature was 60.7°C. The moisture content of the crumb polymer at this time was investigated. In crumbs with temperatures around or above average, the moisture content is extremely low. On the other hand, in the crumbs whose temperature is lower than average, especially when the temperature difference from an average temperature is 9.5 degreeC or more, the moisture content is remarkably high. As an example, when the temperature of the block was measured for the chips containing excessive moisture, it was 35.4°C (a temperature difference of 13.4°C) in winter and 47.4°C (a temperature difference of 13.3°C) in summer. From this result, by measuring the temperature of the crumb-like polymer and focusing on the temperature difference, it is possible to reliably detect crumbs containing excessive moisture regardless of the outside air temperature.

1: Vibrating feeder 2: Rubber crumbs 3: Temperature recording camera 6: Metering device with hopper 7: Pressing machine (pressure forming machine) 8: Dehydration/Drying Step 9: Packaging step 10: Reprocessing steps 11: Abnormal detection signal 12: Regular product (product) 13: Non-compliant products 14: Conveyor 15: Weight measuring device 30: Control device

FIG. 1 is a system configuration diagram of an embodiment of the present invention. Figure 2 shows the results of a verification test as a basis for the basic concept of the present invention. Fig. 3 is a detection example of an embodiment of the present invention.

2: Rubber crumbs

3: Temperature recording camera

6: Metering device with hopper

7: Pressing machine (pressure forming machine)

8: Dehydration/Drying Step

9: Packaging step

10: Reprocessing steps

11: Abnormal detection signal

12: Regular product (product)

13: Non-compliant products

14: Conveyor

15: Weight measuring device

30: Control device

Claims (7)

An inspection method comprising: continuously supplying polymerized, dewatered and dried crumb-like polymer, measuring the temperature of the crumb-like polymer, and detecting the content of the crumb-like polymer based on the temperature difference Excessive moisture crumbs; among which, for the continuously supplied crumb-like polymer, the temperature of each measuring point is measured, the average temperature of a plurality of measuring points is obtained, and the measuring point whose temperature is more than 9.5°C lower than the average temperature is detected. Corresponding crumbs. The inspection method of claim 1, wherein the average temperature of the polymer when the dewatered and dried crumb-like polymer is supplied is 40 to 70°C. The inspection method of claim 1 or 2, wherein the above-mentioned crumbs containing excess moisture are in the form of lumps. The inspection method according to claim 1 or 2, wherein the moisture content of the crumbs containing excess moisture is 1% by mass or more. According to the inspection method of claim 3, the moisture content of the chips containing excessive moisture is 1 mass % or more. An inspection device characterized by comprising: a supply mechanism for continuously supplying the polymer in the form of crumbs after polymerization, dehydration and drying; A temperature measuring means for measuring the temperature of each measuring point of the crumb polymer supplied from the above-mentioned supply means; and a judging means for calculating the temperature difference from the average temperature using the above-mentioned temperature measuring means, and comparing the temperature with the temperature lower than the average temperature The crumbs corresponding to the measurement points with a temperature above 9.5°C are detected as crumbs containing excessive moisture. The inspection device according to claim 6, wherein the temperature measuring means is a temperature recording camera.

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