JP4546861B2 - Contact interface area evaluation method and contact interface area evaluation apparatus - Google Patents

Description

  The present invention relates to a contact interface area evaluation method and a contact interface area evaluation device, and more specifically, the contact interface area between solid objects to be contacted is measured at a molecular level with high accuracy using optical waveguide spectroscopy, and It is possible to measure the contact interface area not only in a stationary state but also in a dynamic state.

  Knowing the area of the contact interface that occurs when at least two types of solid objects come into contact is a long-standing problem in many industrial fields such as adhesion and painting. For example, an adhesive tape is often used as a process material for temporarily fixing various kinds of electronic materials and masking. However, with the miniaturization of electronic circuits, line widths are required to be precise at the molecular level. Masking materials are often used to produce thin line width circuits, but quality control of the adhesion between the masking material and the electronic substrate at the molecular level is indispensable from the viewpoint of improving product yield. It is coming.

  Further, in quality control and development of various tires, information on the contact interface area at the molecular level between the rubber material constituting the tire and the contact surface has become necessary as information directly related to safety. Furthermore, in the case of tires, it is also important to know not only in a stationary state but also a dynamic contact area at the molecular level during running, braking and driving. Furthermore, it is indispensable to know not only the dry road surface but also the contact area at the molecular level with respect to the wet road surface.

Conventionally, a method for evaluating a contact interface area between a solid phase-gas phase interface and a solid phase-liquid phase interface at a molecular level has been provided.
For example, in JP-A-5-99840 (Patent Document 1), a blister phenomenon is caused on an adhesive tape, and a change in the contact area between the adhesive tape and the glass plate is detected optically using a CCD camera. The adhesiveness between the adhesive tape and the substrate is evaluated.
Japanese Patent Application Laid-Open No. 5-41440 (Patent Document 2) also proposes a method for evaluating a contact area from electric resistance.

However, the method described in Patent Document 1 is not accurate because the apparatus is large and complex, and the measurement intensity depends on the number of pixels of the CCD camera. Further, even if the number of pixels of the CCD camera is increased, there is a problem that the S / N ratio is deteriorated and highly reliable data cannot be obtained.
In addition, the method described in Patent Document 2 has a problem in that there is a restriction that the measurement target must have conductivity.
And in these patent documents, it cannot apply to the measurement of the contact interface area at the time of dynamic behaviors, such as a movement and rotation, while the other solid is contacting with one solid. Therefore, for example, the dynamic contact area during braking and braking of the tire cannot be used for measurement.

JP-A-5-99840 JP-A-5-41440

The present invention has been made in view of the above problems, and when a solid material comes into contact with each other, the contact interface area is determined at a molecular level regardless of physical properties such as whether or not these materials have conductivity. It is an object of the present invention to provide a method and an evaluation apparatus that can evaluate with high accuracy.
Furthermore, the contact interface area between these solid objects is not limited to the case where they are brought into contact with each other in a stationary state. An object of the present invention is to make it possible to measure the contact area with the road surface during braking or the like at a molecular level with high accuracy so that the level can be evaluated.

In order to solve the above-mentioned problems, the present invention provides a contact interface area between at least two kinds of first solid objects and second solid objects having different optical refractive indexes, a first solid object serving as an optical waveguide, and the first solid object. The evaluation is performed by using an evanescent wave generated at the contact interface of the second solid object to be brought into contact with the solid object.
The solid material includes a viscoelastic body.

Specifically, in the first invention, the contact interface area between at least two types of the first solid object and the second solid object having different optical refractive indexes is determined by the first solid object serving as an optical waveguide, and the first solid object. It is evaluated using the evanescent wave generated at the contact interface of the second solid object to be contacted with
When incident light is totally reflected at the contact interface between the first solid object and the second solid object, an evanescent wave absorbing material inherent to the second solid object or an evanescent wave absorbing material added to the second solid object. The evanescent wave generated on the second solid object side is absorbed to attenuate the emitted light intensity with respect to the incident light intensity, and the emitted light intensity is detected to contact the first solid object and the second solid object. A method for evaluating a contact interface area, characterized by evaluating the interface area, is provided.

  As described above, in the present invention, the evanescent wave is used in the method for evaluating the contact interface between solids. As shown in FIG. 1, when an evanescent wave is incident on an optical waveguide 1 (first solid object) made of a prism having a high refractive index at an angle θ greater than a critical angle, the incident light R1 has a refractive index. Advancing through the optical waveguide 1 while repeating total reflection R2 at the interface 3 between the different measurement object 2 (second solid object 2) and the optical waveguide 1. At this time, light called an evanescent wave R3 oozes out from the optical waveguide 1 to the measurement object 2 at the totally reflected interface. Since the intensity of the evanescent wave R3 is weak light that exponentially attenuates with respect to the distance from the interface 3, the measurement object 2 and the optical waveguide 1 are not molecularly bonded at the interface 3. The evanescent wave R3 cannot interact with the measurement object 2, and no significant change occurs between the light intensity of the incident light R1 and the light intensity of the outgoing light R4.

  On the other hand, when the measurement object 2 and the optical waveguide 1 are molecularly bonded at the interface 3, the evanescent wave R3 interacts with the measurement object 2. For example, if the measurement object 2 made of the second solid object has an absorbing material that absorbs light of a specific wavelength included in the evanescent wave R3, light of that wavelength is absorbed by the measurement object 2. The light intensity of the outgoing light R4 at that wavelength is reduced compared to the light intensity of the incident light R1. That is, the interface area between the measurement object 2 and the optical waveguide 1 is detected by detecting the intensity of the emitted light and performing a comparison operation with the incident light intensity, for example, obtaining the absorbance from the incident light intensity and the emitted light intensity at the absorption wavelength. Can be evaluated with high accuracy. In this way, only information near the interface can be extracted by using the evanescent wave.

In the evaluation method, if the second solid object to be measured interacts with the evanescent wave and does not absorb the evanescent wave, information on the contact interface cannot be obtained, and the contact interface area is evaluated. I can't. Therefore, if the second solid material has a substance that absorbs the wavelength of the evanescent wave, it is not necessary to add the evanescent wave absorbing material. If not, an evanescent wave absorbing material is added to the second solid material. The addition of the evanescent wave absorbing material may be either a chemical method or a physical method, and is not particularly limited. The evanescent wave absorbing material may be mixed or chemically added to the composition of the second solid material, or may be added first. An evanescent wave absorbing material is applied to the surface of a two-solid material. When this coating method is employed, the contact interface area can be evaluated regardless of the properties of the second solid material.
The evanescent wave absorbing material is not particularly limited as long as it has a functional group that absorbs light from a light source. Examples of the functional group include a hydroxyl group, thionyl group, carbonyl group, ether group, benzene ring, amino group, amide group, nitro group, nitrile group, and various halogen-substituted atomic groups.

Instead of absorbing the evanescent wave and attenuating the emitted light intensity by absorption, the second invention,
Contact between the first solid object serving as an optical waveguide and the second solid object contacting the first solid object with a contact interface area between at least two types of the first solid object and the second solid object having different optical refractive indexes. Evaluates using the evanescent wave generated at the interface,
A substance that emits specific light with respect to the wavelength of the evanescent wave is added to the second solid object,
When incident light is totally reflected at the contact interface between the first solid object and the second solid object, the evanescent wave generated on the second solid object side is emitted as specific light,
There is provided a method for evaluating a contact interface area, wherein the specific light is detected from emitted light and the contact interface area between the first solid object and the second solid object is evaluated.

  The specific light is, for example, fluorescence or phosphorescence, and a substance that absorbs the wavelength of the evanescent wave and generates fluorescence or phosphorescence having a specific wavelength (λ + Δλ) different from the absorption wavelength (λ) is used. The contact interface area is evaluated by adding to a two-solid material by a known chemical method or physical method and detecting the intensity of the emitted light at this specific wavelength.

The fluorescent and phosphorescent substances are not particularly limited, and known fluorescent and phosphorescent substances can be used. Examples of known fluorescent materials include pyrazoline silicate fluorescent materials. Examples of the pyrazoline siliceous fluorescent substance include 1,5 diphenyl 3, p-dinitrophenyl pyrazoline.
In addition, fluorescent or phosphorescent substances of anthracene or inorganic metal complexes can also be used. Examples of the anthracene system include 9,10-diphenylanthracene, rubrene, 9,10-bis (phenylethynyl) anthracene, 5,12- (phenylethynyl) bisnaphthacene, and perylene. The complex center of the metal complex includes samarium, Europium, terbium and dysprosium.

A method for adding a fluorescent or phosphorescent substance is not particularly limited, and examples of the chemical method include a radical reaction and an acid-base reaction. Examples of the radical reaction include addition to an unsaturated bond such as a vinyl group, an acryloyl group, and a methacryloyl group. Examples of the acid-base reaction include a condensation reaction and an addition reaction of a group consisting of a hydroxyl group, a carboxyl group, an amino group, a vinyl group, a thiol group, an epoxy group, an isocyanate group, and an alkoxyl group.
On the other hand, examples of the physical method include a complex formation reaction.
In this way, by combining, adding, or applying a fluorescent or phosphorescent substance to the second solid material to be measured, the contact interface area can be evaluated regardless of the property of the measurement object.

  The method of evaluating the contact interface area by the method of absorbing the evanescent wave of the first invention and attenuating the emitted light intensity, and the method of absorbing the evanescent wave of the second invention and emitting it with specific light such as fluorescence and phosphorescence. Using the method for evaluating the contact interface area by the method, not only the contact interface area between a pair of solid objects in contact with each other but also the contact interface area between two or three types of solid objects is evaluated simultaneously. be able to.

That is, the second solid material is brought into contact with both surfaces of the first solid material,
Alternatively, the second solid material is brought into contact with one surface side of the first solid material and the third solid material is brought into contact with the other surface side of the first solid material,
A contact interface area between the first solid and the second solid,
Alternatively, the contact interface area between the first solid object and the second solid object and the contact interface area between the first solid object and the third solid object can be evaluated simultaneously.
As described above, when the second solid material of the same material is brought into contact with both surfaces of the first solid material and the contact interface area is evaluated on both surfaces, the measurement accuracy can be further increased.

Also, the first solid product, the second solid product, and the third solid product are laminated by bringing the third solid product into contact with the other surface of the second solid product having one surface in contact with the first solid product,
The contact interface area between the first solid object and the second solid object and the contact interface area between the second solid object and the third solid object can be simultaneously evaluated.

Specifically, for example, using the first invention method,
Contacting the second solid with one side of the first solid and contacting the third solid with the other side of the first solid;
An evanescent wave absorbing material having a different absorption wavelength is added to the second solid material and the third solid material, and light having different wavelengths absorbed by the evanescent wave absorbing material is transmitted from the light source to the first solid material. Incident,
The intensity of the emitted light having the different wavelength is detected, and the contact interface area between the first solid object and the second solid object and the contact interface area between the first solid object and the third solid object are simultaneously evaluated.

That is, the second solid object and the third solid object to be measured are brought into contact with both surfaces of the optical waveguide of the first solid object,
By absorbing evanescent waves generated on both sides of the optical waveguide at different absorption wavelengths, the output light intensity at each absorption wavelength is detected, and each contact interface area is evaluated simultaneously by comparing with the incident light intensity. it can.

In addition, when the measurement object is laminated using the first invention method as described above,
Bringing the third solid material into contact with the other surface of the second solid material having one surface in contact with the first solid material;
An evanescent wave absorbing material having a different absorption wavelength is added to the second solid material and the third solid material, and light having different wavelengths absorbed by the evanescent wave absorbing material is transmitted from the light source to the first solid material. Incident,
The intensity of the emitted light having the different wavelengths is detected, and the contact interface area between the first solid object and the second solid object and the contact interface area between the second solid object and the third solid object are simultaneously evaluated.
That is, the contact interface area between the measurement objects can also be evaluated in a state in which the measurement objects are laminated without directly contacting the first solid object to be the optical waveguide.
In this case, it is necessary to make the measurement object to be laminated as thin as possible or to increase the intensity of incident light.

Furthermore, using the first invention method in the same manner as described above, a plurality of measurement objects can be brought into contact with the optical waveguide, and their contact interface areas can be simultaneously evaluated. That is,
Contacting a third solid object in parallel with the second solid object on the same surface of the first solid object;
An evanescent wave absorbing material having a different absorption wavelength is added to the second solid material and the third solid material, and light having different wavelengths absorbed by the evanescent wave absorbing material is transmitted from the light source to the first solid material. Incident,
The intensity of the emitted light having the different wavelengths is detected, and the contact interface area between the first solid object and the second solid object and the contact interface area between the first solid object and the third solid object are simultaneously evaluated.

When the contact interface area of a plurality of measurement objects similar to the above is simultaneously evaluated using the second invention method,
Contacting the second solid with one side of the first solid and contacting the third solid with the other side of the first solid;
A substance that generates different specific light with respect to the wavelength of the evanescent wave generated in the second solid material and the third solid material is added, and the first solid material and the second solid are detected by detecting each specific light. The contact interface area between the first solid material and the third solid material is measured for evaluation.

Further, the third solid material is brought into contact with the other surface of the second solid material, which is in contact with the first solid material at one surface,
A substance that generates different specific light with respect to the wavelength of the evanescent wave generated in the second solid material and the third solid material is added, and the first solid material and the second solid are detected by detecting each specific light. The contact interface area of the object and the contact interface area of the second solid object and the third solid object are simultaneously evaluated.

  Examples of substances (second solid, third solid,...) To be measured using the evaluation method of the present invention include polymer materials, adhesives, paints, various molding materials, and the like. It is done. Among them, it can be suitably used for adhesive parts, adhesive tapes, various films for food, molded parts such as paper feed rollers used in tires and image forming apparatuses, and in which contact interface area is an important function. it can.

Moreover, the evaluation method of the contact interface area of this invention can also evaluate the contact interface area at the time of the behavior of a measuring object (2nd solid object).
That is, the evaluation can be performed by placing the first solid object to be an optical waveguide and rotating, moving, and vibrating the second solid object to be measured along the surface of the first solid object.
Even when the object to be measured rotates, moves, or vibrates on the optical waveguide in this way, an evanescent wave is generated in the contact interface area. Therefore, the first invention method, The contact interface area can be evaluated by the inventive method 2.
For example, when a pressure sensitive adhesive such as an acrylic adhesive tape is used as a measurement object and the pressure is applied to the measurement object, the adhesive is applied to the waveguide surface according to the pressure of the adhesive tape. Interfacial area can also be evaluated at the molecular level.
Further, a paper feed roller mounted on the image forming apparatus is used as a measurement target part, and the surface of the optical waveguide material is given the same property as the copy paper or the same property as the drum surface with which the paper feed roller contacts. And the evaluation of the contact interface area of the paper feed roller to the paper can be obtained with high accuracy.

The present invention is particularly applicable to the evaluation of the contact interface area with the ground contact surface during tire rotation. In that case, the second solid object to be measured is formed as a roller made of the same rubber material as the tire to form a tire sample, and the second solid object is rotated on the first solid object to rotate the tire. The ground contact area can be simulated at the molecular level.
Friction behavior due to contact between the tire and the road surface is a major factor affecting the safety and environmental load of the final product. From this point, the ground contact area of the tire is an important evaluation item not only in a stationary state but also in a dynamic state during running, braking, and driving. Therefore, by rotating a tire sample formed of a material that forms the tread portion of the tire with a motor while applying pressure to the optical waveguide and bringing it into contact, the tire and the ground contact surface during braking, driving, slipping, etc. Evaluation of the contact interface area is very important.

  Further, when the surface of the first solid object that becomes an optical waveguide to be brought into contact with the tire sample as the second solid object is in a dry state, a wet state, and an icing state, the tire rotates on the dry road surface, the wet road surface, and the icing road surface. It is also possible to simulate the ground contact area at the molecular level.

  As 3rd invention, the evaluation apparatus used for the evaluation method of the above-mentioned contact interface area is provided. The evaluation apparatus includes a light source, an optical waveguide material into which light is incident from the light source and in contact with the second solid object to be measured, a detector that detects light emitted from the optical waveguide material, Computation means is provided for calculating the ratio or / and absolute value of the contact interface area by comparing and calculating the intensity of the emitted light and the intensity of the incident light detected by the detector.

The light source is not particularly limited as long as it has an intensity capable of generating an evanescent wave and detected by a detector, but a visible or infrared laser light source, a xenon lamp, a halogen lamp, a mercury lamp, a pulse laser, or the like is preferable. Used for.
The optical waveguide material is not particularly limited as long as it is transparent to incident light, and organic or / and inorganic glass can be used. The thickness of the waveguide is preferably 10 mm to 20 mm.
The detector is not particularly limited as long as the measurement accuracy is guaranteed and suits the purpose, and a photomultiplier tube or a CCD camera is preferably used. Moreover, you may use a spectroscope, an interferometer, a filter, etc. as needed.

Furthermore, means for rotating, moving or vibrating the second solid object to be measured while sliding on the surface of the first solid object to be the optical waveguide material, and the second solid object to the first solid object It is preferable to provide means for applying a required load and bringing it into contact.
By using the above-described evaluation device, it is possible to evaluate the contact interface area with the ground contact surface in various dynamic states such as when the tire rotates, when braking, and when slipping, using the tire sample.

  Furthermore, by providing means for rotating or / and moving the first solid material that becomes the optical waveguide material, the contact interface area in a state in which the first solid material and the second solid material are moving relatively is provided. You can also evaluate. Here, moving the first solid object that is the optical waveguide material means that the first solid object and the second solid object are both moved relative to the second solid object to be measured. It may be moved, or only the first solid object may be moved. Examples of the motion mode include rotation, translation, and vibration. In order to smoothly move relative to the second solid object, for example, a method of sliding the cylindrical first solid object and the cylindrical second solid object while rotating each other, Evaluate the contact interface area in a relatively moving state by rotating in a disk shape and sliding the cylindrical second solid object on the rotating surface while sliding on the first solid object. can do. In some cases, the contact interface area under relative motion conditions can also be evaluated by translating the first solid object in a state where the second solid object is placed on the first solid object that is the optical waveguide material. Can also be done.

In the contact interface area evaluation method of the present invention, when determining the absolute value of the contact interface area, depending on the light source that enters the optical waveguide and the type of detector that detects the emitted light, for example, When infrared light is used as a light source, as a reference, liquid molecules having a basic skeleton similar to the object to be measured are coated on an optical waveguide with a known area, and the emitted light intensity at the absorption wavelength of the basic skeleton is applied. By measuring the absorbance of the sample to be measured, and then performing the same measurement on the sample to be measured later, the known area and the ratio of the absorbance of the sample to the reference can be used to determine the difference between the sample to be measured and the waveguide. It is possible to determine the absolute value of the contact interface area.
In addition, a solution of a fluorescent substance with a known concentration is applied to an optical waveguide with a known area, and a calibration curve is created from the relationship between the fluorescence intensity and the contact interface area, so that the sample to be measured is brought into contact with the optical waveguide. The absolute value of the interfacial area can also be obtained.

  As is clear from the above description, according to the present invention, when light is incident on the first solid object to be the optical waveguide and totally reflected at the contact surface with the second solid object to be brought into contact with the first solid object. The contact interface area is evaluated using an evanescent wave that oozes out to the second solid object side. In the first invention, the evanescent wave is absorbed by the evanescent wave. By detecting the emitted light from the optical waveguide, the contact interface area can be evaluated with high accuracy at the molecular level.

  Further, the contact interface area can be evaluated at a molecular level not only in a stationary state but also in a dynamic state. Therefore, it is possible to evaluate the contact interface area with the ground contact surface during rotation, braking, slipping, etc. of the tire, which is very useful for tire performance evaluation.

The principle of the evaluation method of the first invention is as described in FIG.
In the first embodiment shown in FIG. 2, the above-mentioned FIG. 1 is shown as a specific example, and the contact interface area evaluation apparatus is used to enter a thin plate-like transparent optical waveguide material 10 and the optical waveguide material 10. Light source 11, an objective lens 12 for making light from the light source 11 incident on one end side of the optical waveguide material 10 at an angle θ greater than the critical angle, and outgoing light detection arranged on the other end side of the optical waveguide material 1. CCD camera 13 is provided. In addition, a load adder 14 for applying a required pressure to the measurement object is provided above the optical waveguide 10, and an arithmetic unit 15 connected to the CCD camera 13 is provided.

  In the first embodiment, the rubber sheet 20 to be measured is brought into contact with the upper surface of the optical waveguide member 10 by applying a required pressure with the load adder 14, and the contact interface area of the rubber sheet 20 with respect to the optical waveguide member is evaluated. is doing. That is, the contact interface area between the first solid material made of the optical waveguide material 10 that becomes the first solid material and the second solid material made of the rubber sheet 20 is evaluated.

  The rubber sheet 20 to be measured includes an evanescent wave absorbing material that absorbs the evanescent wave R3 generated on the rubber sheet 20 side at the contact interface S between the optical waveguide member 10 and the rubber sheet 20. In the case where the rubber sheet 20 does not include the evanescent wave absorbing material, the evanescent wave absorbing material is blended with the composition of the rubber sheet 20 when the rubber sheet 20 is formed to form the rubber sheet 20.

The method for evaluating the contact interface area between the optical waveguide member 10 and the rubber sheet 20 is as described with reference to FIG. 1, and light is incident on the optical waveguide member 1 at an angle θ greater than the critical angle. Then, the incident light R1 travels through the optical waveguide member 10 while repeating total reflection R2 at the interface S between the rubber sheet 20 and the optical waveguide member 10 having different refractive indexes. At this time, the evanescent wave R3 exudes to the rubber sheet 20 side from the totally reflected interface S. The evanescent wave R3 is absorbed by the absorbing material of the rubber sheet 20.
At that time, since the intensity of the evanescent wave R3 is weak light that exponentially attenuates with respect to the distance from the interface S, the rubber sheet 20 and the optical waveguide member 10 are molecularly bonded at the interface S. If not, the evanescent wave R3 is not absorbed by the absorbent material of the rubber sheet 20.
That is, if the rubber sheet 20 is in contact with the optical waveguide material 10 at the molecular level at the contact interface S, the evanescent wave is absorbed by the rubber sheet 20, so that the emitted light intensity is reduced. The incident light intensity will not change.

The emitted light from the other end of the optical waveguide member 10 is photographed by a detector 13 composed of a CCD camera, the emitted light intensity is detected, and a detection signal from the detector 13 is transmitted to the computing unit 15.
The calculator 15 compares and calculates the incident light intensity and the detected emitted light intensity to determine the ratio of the contact interface area.

In the second embodiment, the contact interface area is evaluated by the method of the second invention.
A rubber sheet different from that of the first embodiment is used as an object to be measured, and a substance that generates fluorescence or phosphorescence by absorbing evanescent waves is blended in the rubber sheet. Since other configurations are the same as those of the first embodiment, illustration is omitted.
In the case of a rubber sheet that absorbs evanescent waves and generates fluorescence or phosphorescence, light that penetrates the rubber sheet side as evanescent waves can be detected by a detector as emitted light having fluorescence or phosphorescence. Therefore, the contact interface area where the rubber sheet is in contact with the optical waveguide at the molecular level can be obtained from the detected light intensity of fluorescence or phosphorescence.

FIG. 3 shows a third embodiment, in which a rubber sheet 21 is bonded to the upper surface of the optical waveguide member 10 and a resin sheet 22 is bonded to the lower surface. As in the second embodiment, the rubber is formed by the second invention method. The respective contact interface areas of the sheet 21 and the optical waveguide material 10, and the resin sheet 22 and the optical waveguide material 10 are simultaneously obtained.
The rubber sheet 21 is blended with a substance that absorbs evanescent waves and generates fluorescence, while the resin sheet 22 is blended with a substance that absorbs evanescent waves and generates phosphorescence.
In the third embodiment, similarly to the second embodiment, the light emitted from the optical waveguide member 10 is detected by a detector, and the contact interface area between the rubber sheet 21 and the optical waveguide member 10 is determined from the light intensity of the fluorescence. At the same time, the contact interface area between the resin sheet 22 and the optical waveguide member 10 can be obtained from the light intensity of phosphorescence.

Instead of using the method of the second invention, as in the first embodiment, an evanescent wave absorbing material is added to the rubber sheet and the resin sheet that are in contact with the upper and lower surfaces of the optical waveguide material, and the first invention is applied. Also by the method, the contact interface areas of the rubber sheet and the optical waveguide material, and the resin sheet and the optical waveguide material can be simultaneously obtained.
That is, the evanescent wave absorbing material added to the rubber sheet and the resin sheet has different absorption wavelengths, and the wavelength absorbed by the evanescent wave absorbing material of the rubber sheet from the light source and the evanescent wave absorbing material of the resin sheet are absorbed. Light having a different wavelength consisting of the wavelength to be incident on the optical waveguide material. By detecting the emitted light intensity of the different wavelengths with the detector, the contact interface area between the rubber sheet and the optical waveguide material and between the resin sheet and the optical waveguide material can be obtained simultaneously.
Note that the sensitivity on the detector side can be increased by bringing the same material into contact with the both surfaces of the optical waveguide material instead of bringing the same material into contact with the both surfaces of the optical waveguide material 10. .

FIG. 4 shows a fourth embodiment, in which a liquid material 23 is applied to the upper surface of the optical waveguide material 10, and a resin sheet 24 is disposed on the upper surface of the liquid material 23. The coating thickness of the liquid material 23 is made as thin as possible so that the evanescent wave oozes out.
If either the liquid material 23 or the resin sheet 24 exhibits absorption, fluorescence, or phosphorescence, the contact area of the resin sheet 24 with respect to the upper surface of the waveguide member 10 through the liquid material can be obtained. When either the liquid substance 23 or the resin sheet 24 is inactive to incident light, a substance that absorbs evanescent waves and generates fluorescence or phosphorescence may be blended.

  FIG. 5 shows a fifth embodiment, in which a rubber sheet 25 of a measurement object is disposed on the left side of the upper surface of the optical waveguide member 10, a resin sheet 26 is disposed on the right side, and two measurement objects are disposed on the optical waveguide. They are arranged in parallel on the material 10. Similar to the above-described embodiment, the contact interface S-3 between the optical waveguide material 10 and the rubber sheet 25 and the contact interface S between the optical waveguide material 10 and the resin sheet 26 using the first invention method or the second invention method. -4 can be obtained using evanescent waves.

FIG. 6 shows a sixth embodiment, in which a second solid object to be measured is a tire sample 30 and is rotated on the upper surface of the optical waveguide material 10 to obtain a contact interface area with the optical waveguide material 10 at the time of rotation. ing.
The tire sample 30 is formed in the shape of a cylindrical roller from the same composition as the tire, and the rotation support shaft 31 of the hollow portion is fixed through the rotation, so that the rotation support shaft 31 can be rotated at a required speed by a servo motor 32. Further, the tire sample 30 is pressed against the optical waveguide member 10 by applying a required pressure by the load adder 14 disposed above. That is, the tire sample 30 is rotated while applying a pressure corresponding to the contact pressure on the road surface.
In the present embodiment, in order to detect the light emitted from the other end of the optical waveguide member 10, a spectrometer 18 and a photomultiplier tube 19 connected to the spectrometer 18 are used instead of the CCD camera. .

  The tire sample 30 has an evanescent wave absorbing material. Therefore, the contact interface area of the tire sample 30 with respect to the optical waveguide member 10 corresponding to the road surface is detected by the spectroscope 18, the light intensity is increased by a photomultiplier tube, the light intensity is transmitted to the computing unit, and the emitted light Contact interface area is calculated from strength.

When the tire sample is rotated while the surface of the optical waveguide member 10 corresponding to the road surface is wetted, the contact interface area of the tire on the road surface in the rain can be simulated.
Further, when the tire sample is rotated with the surface of the optical waveguide member 10 being frozen, the contact interface area of the tire on ice can be simulated.

FIG. 7 shows a seventh embodiment, in which the optical waveguide member 10 ′ has a cylindrical shape, is horizontally disposed, and is rotated around the axis. A cylindrical solid second solid object 30 ′ is brought into contact with the upper surface of the optical waveguide member 10 ′, and the second solid object 30 ′ is also rotated around the axis to evaluate the contact interface area between the rotating bodies in line contact. is doing.
The second solid material 30 'has an evanescent wave absorbing material.
Since other configurations and operations are the same as those of the other embodiments, the description thereof is omitted.

FIG. 8 shows an eighth embodiment, in which the optical waveguide member 10 "has a disk shape, is horizontally arranged and rotated around the center. The second solid object 30 having a cylindrical shape on the upper surface of the optical waveguide member 10". And the second solid object 30 ”is rotated around the axis, and the contact interface area between the rotating disk and the rotating cylinder is evaluated.
The second solid material 30 ″ has an evanescent wave absorbing material.
Since other configurations and operations are the same as those of the other embodiments, the description thereof is omitted.

  Instead of rotating the optical waveguide material, move it in a linear direction, fix the first solid object in contact with the optical waveguide material, change the speed in the same direction, move it in the opposite direction, It can also be evaluated.

"Example"
Examples 1 to 6 in which the tire sample as the roller shown in FIG. 6 is the measurement target will be described below.
In each of Examples 1 to 6, a xenon lamp was used as the light source 11, and light was guided to the objective lens by an optical fiber. Light exiting the optical fiber passes through the objective lens and the prism (LaSF08, 633 nm n = 1.8785, manufactured by Kogyo Giken) and enters the optical waveguide member 10. The light that passed through the optical waveguide material passed through the prism and objective lens, entered the optical fiber again, and finally was detected by a CCD camera (C7473-36N manufactured by Hamamatsu Photonics) through a spectroscope connected to the optical fiber.

The roller to be measured as a tire sample 30 was made of a composition in which the following components were blended as shown in Table 1, kneaded and molded by press vulcanization at 170 ° C. for 20 minutes. The roller had a diameter of 20 mm and an axial length of 50 mm.
The various chemicals used are as follows.
Rubber: JSR SBR (styrene butadiene copolymer) 1502
Carbon Black: Show Black N220 Showa Cabot
Antiaging agent: Nouchi 6C manufactured by Ouchi Shinsei Chemical Industry
Stearic acid: Nippon Oil & Fats Stearate Sulfur: Tsurumi Chemical Powder Sulfur Vulcanization Accelerator: Ouchi Shinsei Chemical Industry Noxeller NS

As a preliminary experiment, the absorption intensity lbr of a benzene ring skeleton of 1502 cm ⁻¹ with a liquid styrene butadiene copolymer (styrene content 23.5%) applied to the surface of the optical waveguide material 11 at a thickness of 50 μm The absorption intensity was measured.

Next, a tire sample 30 made of a rubber roller having a diameter of 50 mm was placed on the optical waveguide member 10, and the following loads were sequentially applied by the load adder 14 and brought into pressure contact with the optical waveguide member 10. Further, the rotation support shaft 31 of the tire sample 30 was connected to a servo motor 32 and was driven to rotate at a rotation speed of 1200 rpm. A three-component force meter (not shown) is attached to the rotation support shaft 31 so that the force in three directions can be detected based on the axial direction.
While applying a load of 1.0 kgf in Example 1, 3.0 kgf in Example 2, and 5.0 kgf in Example 3 to the tire sample 30 while rotating at the rotational speed, The absorption intensity lbr of 1502 cm ⁻¹ was measured, and the contact interface area was evaluated by the following formula (1).

Contact interface area = cell area × absorbance of measurement object / absorbance of reference (1)
The measurement object refers to a sample tire.
The measurement was performed three times with each load applied, and the average value and standard deviation were obtained.

In Examples 4 to 6, 1 part by weight of perylene as a fluorescent material was blended and kneaded with 100 parts by weight of the rubber composition, and a roller-shaped tire sample 30 having the same shape as in Examples 1 to 3 was measured. Formed as a product.
In Examples 4 to 6, as a preliminary experiment, a solution in which acetone and rhodamine B were 100: 1 was applied to the surface of the optical waveguide member 10, and the fluorescence intensity at a wave number of 535 cm ⁻¹ was measured in advance.
Next, a load of 1.0 kgf was applied to the sample tire 30 in Example 4, 3.0 kgf in Example 5, 5.0 kgf in Example 6, and benzene at 1502 cm -1 while rotating at the rotational speed. The fluorescence intensity of the ring was measured, and the contact interface area was evaluated by the following formula (2).

  Contact interface area = cell area × fluorescence intensity of measurement object / reference fluorescence intensity (2)

Table 2 shows the measurement results of Examples 1 to 6.

As is clear from Table 2, in each of Examples 1 to 6, the contact interface area between the optical waveguide member 10 and the tire sample of the measurement object could be accurately evaluated.
In particular, when the fluorescent materials of Examples 4 to 6 were added to the sample tire of the measurement object, the standard deviation was reduced, and it was confirmed that the contact interface area could be evaluated with high accuracy.

  In the present invention, the contact interface area is an important element for maintaining the quality of adhesives, adhesive tapes, various films, polymer molding materials, tires, etc., and when these contact interface areas are evaluated at a molecular level with high accuracy. It can be used suitably.

It is explanatory drawing which shows the principle of the evaluation method of the contact interface area of this invention. It is the schematic which shows the evaluation method of the contact interface area of 1st Embodiment of this invention using the schematic of an evaluation apparatus. It is the schematic which shows 3rd Embodiment of this invention. It is the schematic which shows 4th Embodiment of this invention. It is the schematic which shows 5th Embodiment of this invention. It is the schematic which shows 6th Embodiment of this invention. It is the schematic which shows 7th Embodiment of this invention. It is the schematic which shows 8th Embodiment of this invention.

Explanation of symbols

10 Optical waveguide material (first solid material)
DESCRIPTION OF SYMBOLS 11 Light source 12 Objective lens 13 CCD camera 18 Spectrometer 19 Photomultiplier tube 20 Rubber sheet (2nd solid substance)
30 Tire sample (second solid)
R1 Incident light R2 Total reflection light R3 Evanescent wave R4 Outgoing light S (S-1, S-2 ...) Interface

Claims (11)

Contact between the first solid object serving as an optical waveguide and the second solid object contacting the first solid object with a contact interface area between at least two types of the first solid object and the second solid object having different optical refractive indexes. Evaluates using the evanescent wave generated at the interface,
When incident light is totally reflected at the contact interface between the first solid object and the second solid object, an evanescent wave absorbing material inherent to the second solid object or an evanescent wave absorbing material added to the second solid object. The evanescent wave generated on the second solid object side is absorbed to attenuate the emitted light intensity with respect to the incident light intensity, and the emitted light intensity is detected to contact the first solid object and the second solid object. A method for evaluating a contact interface area, wherein the interface area is evaluated. Contact between the first solid object serving as an optical waveguide and the second solid object contacting the first solid object with a contact interface area between at least two types of the first solid object and the second solid object having different optical refractive indexes. Evaluates using the evanescent wave generated at the interface,
A substance that emits specific light with respect to the wavelength of the evanescent wave is added to the second solid object,
When incident light is totally reflected at the contact interface between the first solid object and the second solid object, the evanescent wave generated on the second solid object side is emitted as specific light,
A method for evaluating a contact interface area, wherein the specific light is detected from emitted light, and a contact interface area between the first solid object and the second solid object is evaluated.   The specific light is fluorescence or phosphorescence, and a substance having fluorescence or phosphorescence for the wavelength of the evanescent wave is mixed with the second solid material, chemically added, or applied to the contact surface with the second solid material. The method for evaluating a contact interface area according to claim 2. Contacting the second solid object on both sides of the first solid object;
Alternatively, the second solid material is brought into contact with one surface side of the first solid material and the third solid material is brought into contact with the other surface side of the first solid material,
A contact interface area between the first solid and the second solid,
Alternatively, the contact interface area of the first solid object and the second solid object and the contact interface area of the first solid object and the third solid object are simultaneously evaluated. Evaluation methods. The third solid material is brought into contact with the other surface of the second solid material whose one surface is in contact with the first solid material, and the first solid material, the second solid material, and the third solid material are laminated,
The contact interface area between the first solid material and the second solid material and the contact interface area between the second solid material and the third solid material are simultaneously evaluated. Evaluation method of contact interface area.   The contact according to any one of claims 1 to 5, wherein the first solid object is placed and evaluated while rotating, moving, and vibrating the second solid object along a surface of the first solid object. Evaluation method of interfacial area.   The second solid object is formed as a roller made of the same rubber material as the tire to form a tire sample, the second solid object is rotated on the first solid object, and the ground contact area during tire rotation is The contact interface area evaluation method according to any one of claims 1 to 6, wherein simulation is performed at a level.   The contact surface of the first solid object to be brought into contact with the second solid object is set in a dry state, a wet state, and an icing state, and a ground contact area during tire rotation on a dry road surface, a wet road surface, and an icing road surface is simulated at a molecular level. The contact interface area evaluation method according to any one of claims 1 to 7. An evaluation apparatus for use in the method for evaluating a contact interface area according to any one of claims 1 to 8,
A light source;
A thin plate-shaped optical waveguide material in which light is incident from the light source and the second solid object to be measured is contacted;
A detector for detecting light emitted from the optical waveguide material;
A contact interface area evaluation device comprising: a calculation means for calculating a ratio or / and an absolute value of the contact interface area by comparing and calculating the intensity of the emitted light and the intensity of the incident light detected by the detector. .   Means for rotating, moving or vibrating the second solid object while being in sliding contact with the surface of the first solid object; and means for bringing the second solid object into contact with the first solid object under a required load. The apparatus for evaluating a contact interface area according to claim 9.   The apparatus for evaluating a contact interface area according to claim 9 or 10, further comprising means for rotating or / and moving the first solid object serving as the waveguide.

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